TGF-ß1 Improves Biomechanical Strength by Extracellular Matrix Accumulation Without Increasing the Number of Tenogenic Lineage Cells in a Rat Rotator Cuff Repair Model.

BACKGROUND: Transforming growth factor ß1 (TGF-ß1) positively regulates the tenogenic marker genes scleraxis ( Scx) and tenomodulin ( Tnmd) in mesenchymal progenitors in vitro. However, little is known about the effect of TGF-ß1 on the expression of tenogenic markers during rotator cuff (RC) healing in rats. HYPOTHESIS: TGF-ß1 improves the biomechanical properties and histological maturity of reparative tissue in a rat RC repair model by stimulating the growth of tenogenic cells. STUDY DESIGN: Controlled laboratory study. METHODS: Adult male Sprague-Dawley rats (N = 180) underwent unilateral supraspinatus tendon-to-bone surgical repair and were randomly treated with a gelatin hydrogel presoaked in TGF-ß1 (100 ng) or phosphate-buffered saline. The effects of TGF-ß1 on RC healing were investigated at 2, 4, 6, 8, and 12 weeks postoperatively by immunostaining for proliferating cell nuclear antigen, by real-time reverse transcription polymerase chain reaction and in situ hybridization or immunostaining for enthesis-related markers (SRY-box containing gene 9 [ Sox9], Scx, and Tnmd), and by real-time reverse transcription polymerase chain reaction and immunostaining for type I and III collagen. At 6 and 12 weeks postoperatively, biomechanical testing, micro-computed tomography, and biochemical analysis were also performed. At 2 and 4 weeks postoperatively, mesenchymal stem cell-related markers, phospho-Smad2, and matrix metalloproteinase 9 (MMP-9) and MMP-13 were assessed by immunostaining. RESULTS: The TGF-ß1-treated group had significantly higher ultimate load to failure and tissue volume at 6 and 12 weeks postoperatively and a higher collagen content at 12 weeks compared with the saline group. Tendon-related gene expression, histological maturity, cell proliferation, and mesenchymal stem cell-related marker immunoreactivity were not affected by exogenously administrated TGF-ß1 at all time points. In the TGF-ß1-treated group, the percentage of phospho-Smad2-positive cells within the healing tissue increased, whereas the expression of MMP-9 and MMP-13 significantly decreased at 2 and 4 weeks postoperatively. CONCLUSION: TGF-ß1 enhances formation of tough fibrous tissues at the healing site by inhibiting MMP-9 and MMP-13 expression to increase collagen accumulation but without the growth of tenogenic lineage cells. CLINICAL RELEVANCE: These findings suggest that TGF-ß1 could be used for enhancing biomechanical strength after RC surgical repair.

Enhancement of rotator cuff tendon-bone healing with fibroblast growth factor 2 impregnated in gelatin hydrogel sheets in a rabbit model.

BACKGROUND: Application of fibroblast growth factor 2 (FGF-2) may improve the healing response after rotator cuff (RC) surgical repair. This study aimed to determine whether FGF-2-impregnated gelatin hydrogel sheet (GHS) incorporation into the bony trough on the greater tuberosity facilitates healing after RC surgical repair in rabbits. METHODS: We assigned 120 adult male Japanese white rabbits treated with unilateral surgery for supraspinatus tendon repair into the following groups: suture-only group (suture); suture and GHS with phosphate-buffered saline (carrier); suture and GHS with 3 µg of FGF-2 (F3); and suture and GHS with 30 µg of FGF-2 (F30). The effect of FGF-2 was assessed using histologic, biomechanical, and microcomputed tomography evaluations at 2, 6, and 12 weeks. RESULTS: At 12 weeks, loose fibrovascular tissues emerged at the repair site in the suture and carrier groups and dense tendon-like tissues in the F3 and F30 groups, which demonstrated significantly higher ultimate load-to-failure and stress-to-failure at 12 weeks than that in the suture and carrier groups. Microcomputed tomography imaging showed ectopic calcification formation in some specimens from each group. Appearances or frequencies were similar among groups. The histologic and biomechanical effects of FGF-2 on RC healing were obvious at ≥6 weeks postoperatively. CONCLUSION: FGF-2-impregnated GHS incorporation into the bony trough on the greater tuberosity before RC surgical repair is feasible and results in histologic and biomechanical improvements during RC healing in rabbits. No detrimental effect on ectopic calcification was observed.

Neuropeptide glutamic acid-isoleucine (NEI)-induced paradoxical sleep in rats.

Neuropeptideglutamic acid-isoleucine (NEI) as well as melanin concentrating hormone (MCH) is cleaved from the 165 amino acid protein, prepro-melanin concentrating hormone (prepro-MCH). Among many physiological roles of MCH, we demonstrated that intracerebroventricular (icv) injection of MCH induced increases in REM sleep episodes as well as in non REM sleep episodes. However, there are no studies on the effect of NEI on the sleep-wake cycle. As for the sites of action of MCH for induction of REM sleep, the ventrolateral periaqueductal gray (vlPAG) has been reported to be one of its site of action. Although MCH neurons contain NEI, GABA, MCH, and other neuropeptides, we do not know which transmitter(s) might induce REM sleep by acting on the vlPAG. Thus, we first examined the effect of icv injection of NEI on the sleep-wake cycle, and investigated how microinjection of either NEI, MCH, or GABA into the vlPAG affected REM sleep in rats. Icv injection of NEI (0.61µg/5µl: n=7) significantly increased the time spent in REM episodes compared to control (saline: 5µl; n=6). Microinjection of either NEI (61ng/0.2µl: n=7), MCH (100ng/0.2µl: n=6) or GABA (250mM/0.2µl: n=7) into the vlPAG significantly increased the time spent in REM episodes and the AUC. Precise hourly analysis of REM sleep also revealed that after those microinjections, NEI and MCH increased REM episodes at the latter phase, compared to GABA which increased REM episodes at the earlier phase. This result suggests that NEI and MCH may induce sustained REM sleep, while GABA may initiate REM sleep. In conclusion, our findings demonstrate that NEI, a cleaved peptide from the same precursor, prepro-MCH, as MCH, induce REM sleep at least in part through acting on the vlPAG.

A Novel and Multidisciplinary Strategy for Cesarean Delivery With Placenta Percreta: Intraoperative Embolization in a Hybrid Suite.

Cesarean deliveries in patients with placenta accreta often are accompanied by life-threatening bleeding and sometimes death. A novel, multidisciplinary approach that uses uterine embolization after cesarean delivery recently has been advocated; however, embolization in the radiology department requires transfer of postoperative patients, which could increase maternal mortality and morbidity. In a case of severe placenta accreta, we planned a stepwise treatment, including cesarean delivery without separation of the placenta followed by intraoperative uterine arterial embolization in a hybrid operating room, followed by hysterectomy a few weeks after cesarean delivery. With no postpartum bleeding, complete hysterectomy was performed uneventfully 25 days later.

FGF-2 Stimulates the Growth of Tenogenic Progenitor Cells to Facilitate the Generation of Tenomodulin-Positive Tenocytes in a Rat Rotator Cuff Healing Model.

BACKGROUND: Fibroblast growth factor (FGF)-2 has the potential to enhance tendon-to-bone healing after rotator cuff (RC) injury. HYPOTHESIS: FGF-2 stimulates tenogenic differentiation of progenitors to improve the biomechanical strength and histological appearance of repaired RCs in rats. STUDY DESIGN: Controlled laboratory study. METHODS: Adult male Sprague-Dawley rats (N = 156) underwent unilateral surgery to repair the supraspinatus tendon to insertion sites. The FGF-2-treated group (gelatin hydrogel containing 5 µg of FGF-2) and a control group (gelatin hydrogel only) were compared to investigate the effects of FGF-2 at 2, 4, 6, 8, and 12 weeks postoperatively. Biomechanical testing was performed at 6 and 12 weeks. Semiquantitative histological analysis and immunohistochemical analysis for the proliferating cell nuclear antigen (PCNA) were performed, and the expression of tendon-related markers, including Scleraxis (Scx) and Tenomodulin (Tnmd), was monitored by real-time reverse transcription polymerase chain reaction (RT-PCR) and in situ hybridization. SRY-box containing gene 9 (Sox9) expression was monitored by RT-PCR and immunohistochemical analysis. At 2 and 4 weeks, immunohistochemical analysis for mesenchymal stem cell (MSC) markers was also performed. RESULTS: The FGF-2-treated group demonstrated a significant improvement in mechanical strength at 6 and 12 weeks and significantly higher histological scores than the control group at ≥4 weeks. The average incidence of PCNA-positive cells was significantly higher at 2 and 4 weeks, and more cells expressing MSC markers were detected at the insertion site in the FGF-2-treated group. The expression level of Scx increased significantly in the FGF-2-treated group from 4 to 8 weeks, while the Tnmd level increased significantly from 4 to 12 weeks postoperatively. The localization of Tnmd overlapped with the locations of reparative tissues accompanying collagen fibers with an aligned orientation. Sox9 expression was significantly upregulated at 4 weeks in the FGF-2-treated group. CONCLUSION: FGF-2 promotes growth of the tenogenic progenitor cells, which participate in tendon-to-bone healing, resulting in biomechanical and histological improvement of the repaired RC. CLINICAL RELEVANCE: These findings provide clues regarding the clinical development of regenerative repair strategies for RC injury.

Local Application of Gelatin Hydrogel Sheets Impregnated With Platelet-Derived Growth Factor BB Promotes Tendon-to-Bone Healing After Rotator Cuff Repair in Rats.

PURPOSE: To determine whether the local application of platelet-derived growth factor BB (PDGF-BB) in hydrogel sheets would promote healing and improve histologic characteristics and biomechanical strength after rotator cuff (RC) repair in rats. METHODS: To assess the effect of PDGF-BB on tendon-to-bone healing we divided 36 adult male Sprague-Dawley rats treated with bilateral surgery to repair the supraspinatus tendon at its insertion site into 3 groups: group 1 = suture-only group; group 2 = suture and gelatin hydrogel sheets impregnated with phosphate-buffered saline (PBS); and group 3 = suture and gelatin hydrogel sheets impregnated with PDGF-BB (0.5 µg). Semiquantitative histologic evaluation was carried out 2, 6, and 12 weeks later; cell proliferation was assessed 2 and 6 weeks postoperatively by immunostaining for proliferating cell nuclear antigen (PCNA), and biomechanical testing, including ultimate load to failure, stiffness, and ultimate stress to failure, was performed 12 weeks after the operation. RESULTS: At 2 weeks, the average percentage of PCNA-positive cells at the insertion site was significantly higher in group 3 (40.5% ± 2.4%) than in group 1 (32.1% ± 6.9%; P = .03) and group 2 (31.9% ± 3.7%; P = .02). At 2 and 6 weeks, the histologic scores were similar among the 3 groups. At 12 weeks, the histologic score was significantly higher in group 3 (10.3 ± 0.8) than in group 1 (8.5 ± 0.5; P = .002) or group 2 (8.8 ± 0.8; P = .009), whereas ultimate load to failure, stiffness, and ultimate load to stress (normal control population, 44.73 ± 9.75 N, 27.59 ± 4.32 N/mm, and 21.33 ± 4.65 N/mm(2), respectively) were significantly higher in group 3 (28.28 ± 6.28 N, 11.05 ± 2.37 N/mm, and 7.99 ± 2.13 N/mm(2), respectively) than in group 1 (10.44 ± 1.98 N, 4.74 ± 1.31 N/mm, and 3.28 ± 1.27 N/mm(2), respectively; all P < .001) or group 2 (11.85 ± 2.89 N, 5.86 ± 1.75 N/mm, and 3.31 ± 0.80 N/mm(2), respectively; all P < .001). CONCLUSIONS: The placement of a PDGF-BB-impregnated hydrogel sheet just lateral to a transected and acutely reattached supraspinatus tendon produced significantly more PCNA-positive cells at 2 weeks and greater collagen fiber orientation, ultimate failure loads, stiffness, and stress to failure at 12 weeks than did a PBS-impregnated hydrogel sheet. No differences in vascularity or cellularity were observed. CLINICAL RELEVANCE: The local application of PDGF-BB-impregnated gelatin hydrogel may help to promote tendon-to-bone healing after RC repair in humans.

Effect of Postoperative Passive Motion on Rotator Cuff Reconstruction With Acellular Dermal Matrix Grafts in a Rat Model.

BACKGROUND: Although postoperative rehabilitation is critical for rotator cuff tendon-to-bone healing and shoulder function recovery, no standardized protocol has been established. HYPOTHESIS: Postoperative immediate passive motion is detrimental to tendon-to-bone remodeling and tendon maturation after rotator cuff acellular dermal matrix (ADM) grafting, although postoperative delayed passive motion does no harm. STUDY DESIGN: Controlled laboratory study. METHODS: Male Sprague-Dawley rats underwent rotator cuff reconstruction with ADM grafts. Their shoulders were immobilized for 2 weeks thereafter. The rats were assigned to 3 different rehabilitation protocols: (1) immobilization without passive motion (nonpassive motion [N-PM], controls), (2) immobilization with immediate passive motion (I-PM), and (3) immobilization with delayed passive motion (D-PM). Specimens obtained 2, 6, and 12 weeks postoperatively were analyzed histologically, and semiquantitative histomorphological measurements of collagen organization, vascularity, and cellularity were obtained; the area of interest was divided into 2 zones, the midsubstance of the graft and the graft-bone interface. Another set of samples taken at 12 weeks was subjected to biomechanical analysis. RESULTS: At 2 weeks, there was no significant difference among the groups in terms of semiquantitative histomorphological measurements of collagen organization, vascularity, and cellularity. At 6 weeks, collagen organization at the insertion site was significantly poorer in I-PM than in N-PM and D-PM rats (P = .0095). At 12 weeks, collagen organization at the insertion site and midsubstance of ADM grafts was also significantly poorer in I-PM rats (P = .0125 and P = .0018, respectively), and ultimate load-to-failure was lower in this group (P = .0043). CONCLUSION: While postoperative immediate passive motion was detrimental to remodeled tendon-to-bone healing and to the tendon maturation of ADM grafts placed in the rotator cuff tendon defects, delayed passive motion did no harm. CLINICAL RELEVANCE: For patients with 6-week immobilization after rotator cuff reconstruction, we recommend that early passive motion be started no sooner than 3 weeks after surgery. Immediate early passive motion should be avoided.

Clonidine induces sedation through acting on the perifornical area and the locus coeruleus in rats.

BACKGROUND: The main target site of action for the sedative clonidine (CLO), an α2 adrenoceptor agonist, has been considered to be the locus coeruleus (LC). However, previous reports suggest other sites of action of CLO than the LC. Our previous studies suggested that the neuronal activities in the perifornical area (Pef) could influence the sedative or the anesthetic level induced by anesthetics. Therefore, we examined whether microinjection of CLO into the Pef might induce sedation in rats. MATERIALS AND METHODS: Fifty-five Wistar rats were used. The cortical norepinephrine (NE) and acetylcholine (ACh) effluxes were detected using microdialysis and measured by high-performance liquid chromatography in samples collected every 20 minutes. First, we injected CLO (100, 300, and 1000 µg/kg cumulative doses) intraperitoneally (IP) and observed the changes in NE or ACh efflux. Second, we injected CLO (4.8 µg in 0.2 µL) or saline (0.2 µL) into the LC or the Pef and observed the changes in NE or ACh efflux for 2 hours. Finally, a sedative/anesthetic score was obtained after IP, LC or Pef microinjection of CLO. RESULTS: IP injection of CLO induced sedation and resulted in a dose-dependent attenuation of the cortical effluxes of both NE and ACh (P<0.001). Microinjection of CLO either into the LC or the Pef induced sedation and significantly decreased the cortical NE efflux (P<0.001). Cortical ACh efflux was significantly reduced by microinjection of CLO into the Pef but not by microinjection into the LC (P<0.05). CONCLUSION: The Pef and the LC are responsible for the sedative action of CLO in rats.

Effect of immobilization on rotator cuff reconstruction with acellular dermal matrix grafts in an animal model.

INTRODUCTION: Using a rat model we determined whether immobilization improves tendon-to-bone healing and tendon maturation after rotator cuff reconstruction with acellular dermal matrix (ADM) grafts. METHODS: Sprague-Dawley rats were randomly assigned to 3 equal groups. All rats were subjected to rotator cuff reconstruction and their shoulder was not immobilized (N-IM controls) or immobilized for 2- or 6 weeks immediately thereafter (2- and 6-IM groups, respectively). After detaching the rotator cuff including the full-thickness supraspinatus tendon at its insertion on the greater tuberosity, a defect was created. ADM patches were used for rotator cuff reconstruction. Specimens obtained 2, 6, and 12 weeks after surgery were subjected to semiquantitative histomorphological measurements to assess cellularity, vascularity, and collagen organization. In addition, specimens at 12 weeks were submitted for biomechanical analysis. RESULTS: Cell density decreased over time in all 3 groups; there was no significant difference among the groups at 2 weeks. However, the 6-IM group harbored more cells in the tendon-to-bone interface than the 2-IM group at 6 weeks and the N-IM group at 12 weeks. Vascularity in the interface decreased over time in the N-IM and 2-IM groups but not the 6-IM rats. At 6 and 12 weeks, the 2-IM group manifested better collagen organization than the other groups. The 2-IM group exhibited higher ultimate load-to-failure than the other groups. Stiffness was similar in the 3 groups. CONCLUSION: Remodeling of ADM grafts placed in rat rotator cuff defects was promoted by 2- but not 6-week immobilization.

Melanin concentrating hormone induces hippocampal acetylcholine release via the medial septum in rats.

Among various actions of melanin concentrating hormone (MCH), its memory function has been focused in animal studies. Although MCH neurons project to various areas in the brain, one main target site of MCH is hippocampal formation for memory consolidation. Recent immunohistochemical study shows that MCH neurons directly project to the hippocampal formation and may indirectly affect the hippocampus through the medial septum nucleus (MS). It has been reported that sleep is necessary for memory and that hippocampal acetylcholine (ACh) release is indispensable for memory consolidation. However, there is no report how MCH actually influences the hippocampal ACh effluxes in accordance with the sleep-wake cycle changes. Thus, we investigated the modulatory function of intracerebroventricular (icv) injection of MCH on the sleep-wake cycle and ACh release using microdialysis techniques. Icv injection of MCH significantly increased the rapid eye movement (REM) and non-REM episode time and the hippocampal, not cortical, ACh effluxes. There was a significant correlation between REM episode time and hippocampal ACh effluxes, but not between REM episode time and cortical ACh effluxes. Microinjection of MCH into the MS increased the hippocampal ACh effluxes with no influence on the REM episode time. It appears that the effect sites of icv MCH for prolongation of REM episode time may be other neuronal areas than the cholinergic neurons in the MS. We conclude that MCH actually increases the hippocampal ACh release at least in part through the MS in rats.

Papillary muscle sandwich plasty for the treatment of functional mitral valve regurgitation.

We evaluated the availability of original "sandwich plasty" for the treatment of functional mitral regurgitation (FMR) associated with ischemic heart disease (IHD) and aortic valve disease (AVD). Forty-three patients were reviewed, including 27 IHD patients and 16 AVD patients. Preoperatively severe FMR was detected in 14 patients, moderate FMR in 26, and mild FMR in 3. The papillary muscle heads of anterior leaflets and posterior leaflets were approximated using Teflon-pledgeted 3-0 Ticron sutures at anterolateral and posteromedial commissural portions. After surgery, residual moderate FMR was observed in 1 patient and mild FMR in 3 patients. Tenting height of the mitral valve significantly decreased. FMR free rates 2 years after surgery were 93% among IHD patients and 83% in AVD patients. "Sandwich plasty" was simple and effective for the treatment of functional FMR caused by tethering effects due to left ventricular dilatation.

Calcium-induced calcium release from the sarcoplasmic reticulum can be evaluated with a half-logistic function model in aequorin-injected cardiac muscles.

PURPOSE: Release of calcium (Ca(2+)) from the sarcoplasmic reticulum (SR) induced by Ca(2+) influx through voltage-dependent sarcolemmal L-type Ca(2+) channels (CICR) in cardiac muscle cells has been implicated as a potential target contributing to anesthetic-induced myocardial depression. In an earlier study, we found that (1) a half-logistic (h-L) function, which represents a half-curve of a sigmoid logistic function with a boundary at the inflection point, curve-fits the first half of the ascending phases of the isometric myocardial tension and isovolumic left ventricular (LV) pressure waveforms better than a mono-exponential (m-E) function and (2) the h-L time constants are useful as inotropic indices. We report here our investigation of the potential application of an h-L function to the analysis of the first half of the ascending phase of the Ca(2+) transient curve (faCaT) that precedes and initiates myocardial contraction and the increase in LV pressure. METHODS: Ca(2+) transients (CaT) were measured using the Ca(2+)-sensitive photoprotein aequorin, which was microinjected into seven isolated rabbit right ventricular and 15 isolated mouse LV papillary muscles. The faCaT data from the beginning of twitch stimulation to the maximum of the first-order time derivative of Ca(2+) concentration (dCa/dt(max)) was curve-fitted by the least-squares method using h-L and m-E function equations. RESULTS: The mean correlation coefficient (r) values of the h-L and m-E curve-fits for the faCaTs were 0.9740 and 0.9654 (P < 0.05) in the rabbit and 0.9895 and 0.9812 (P < 0.0001) in the mouse. CONCLUSION: The h-L curves tracked the amplitudes and time courses of the faCaTs in cardiac muscles more accurately than m-E functions. Based on this result, we suggest that the h-L time constant may be a more reliable index than the m-E time constant for evaluating the rate of CICR from the SR in myocardial Ca(2+) handling. The h-L approach may provide a more useful model for the study of CICR during the contraction process induced by anesthetic agents.

[Femoral and sciatic nerve blocks for open reduction and internal fixation of a femoral condylar fracture in a patient with post-polio syndrome].

The post polio symdrome (PPS) refers to the development of delayed neuromuscular symptoms among survivors, years after the initial presentation of acute poliomyelitis. The symptoms of PPS vary widely and include flaccid palsy, muscle weakness, scoliosis, osteoarthritis, gait disturbance, sleep apnea syndrome (SAS), dysphagia, chronic lung dysfunction, and others. We report the successful combination of peripheral nerve blocks, femoral and sciatic nerve blocks, for surgery on the lower extremity in a patient with PPS. A 51-year-old man with continuous positive airway pressure therapy for restrictive ventilatory impairment due to scoliosis and SAS as part of the PPS was scheduled for open reduction and internal fixation (OR-IF) for a right femoral condylar fracture. Respiratory function tests demonstrated a vital capacity (VC) 1.41l (41% predicted). Arterial blood gas analysis on room air was; pH 7.376, PaCO2 55.0 mmHg, and PaO2 77.9 mmHg. With the patient in the supine position, ultrasound-guided right femoral nerve block in the infra-inguinal region was performed using 1.5% mepivacaine 10 ml and 0.75% ropivacaine 5 ml, followed by sciatic nerve block in the popliteal fossa using 1.5% mepivacaine 8 ml and 0.75% ropivacaine 4 ml in the prone position. OR-IF of the fractured femoral condyle was then successfully performed with propofol under spontaneous ventilation. Postoperatively, there were no adverse events; respiratory function was adequate, and his pain was within manageable bounds. Femoral and sciatic nerve blocks are safe and effective anesthetic methods for lower extremity surgery in patients with restrictive ventilatory impairment and hypercapnia due to scoliosis and SAS as PPS.

[Experience of participating in the 14th Nepal Cleft Lip and Palate Surgery Project].

Adventist Development and Relief Agency (ADRA) Japan, a non governmental organization (NGO), following an official request of Federal Democratic Republic of Nepal Government has organized Nepal Cleft Lip and Palate Surgery Project since 1995. We participated in the 14th Project as one of the anesthesiologists from 7th to 22nd November 2009 and performed general anesthesia with a Nepalese anesthetist without a medical license in Sheer Memorial Hospital. Use of unfamiliar anesthetic medications and limited medical devices made us understand the difficulty of anesthetic management. This valuable anesthetic experience will be useful for us in general anesthetic management in the future.

[Effect sites of anesthetics in the central nervous system network--looking into the mechanisms for natural sleep and anesthesia].

We showed the effect sites of anesthetics in the central nervous system (CNS) network. The thalamus is a key factor for loss of consciousness during natural sleep and anesthesia. Although the linkages among neurons within the CNS network in natural sleep are complicated, but sophisticated, the sleep mechanism has been gradually unraveled. Anesthesia disrupts the link-ages between cortical and thalamic neurons and among the cortical neurons, and thus it loses the integration of information derived from the arousal and sleep nuclei. It has been considered that anesthesia does not share the common pathway as natural sleep at the level of unconsciousness, because anesthetics have multiple effect sites within CNS network and may induce disintegration among neurons. Recent literatures have shown that the effects of anesthetics are specific rather than global in the brain. It is interesting to note that thalamic injection of anti-potassium channel materials restored consciousness during inhalation anesthesia, and that the sedative components of certain intravenous anesthesia may share the same pathway as natural sleep. To explore the sensitivity and susceptibility loci for anesthetics in the thalamocortical neurons as well as arousal and sleep nuclei within CNS network may be an important task for future study.

Microinjection of propofol into the perifornical area induces sedation with decreasing cortical acetylcholine release in rats.

BACKGROUND: Among many neurotransmitter systems in the central nervous system, the cholinergic system has been shown to contribute to propofol's sedative/anesthetic effects, because it has been shown that cholinesterase inhibitor reverses the level of propofol-induced unconsciousness in humans. It has been reported that intraperitoneal injection of propofol induced sedative/anesthetic actions and decreased the release of acetylcholine (Ach) from the rat cortex. However, the sites of action of propofol in the cholinergic pathway and its related pathways remain unresolved. We studied whether microinjection of propofol into the nuclei in the cholinergic pathway and its related pathways may induce sedation and decrease Ach from the cortex. METHODS: Thirty-seven male Wistar rats weighing 270 to 320 g were used. Almost 5 days before the experiments, 23 rats anesthetized with pentobarbital (50 mg/kg) were outfitted with an electroencephalogram (EEG) socket, a microdialysis cannula in the cortex, and an intraperitoneal tube or a microinjection tube into the basal forebrain (BF), the perifornical area (Pef), or the striatum. The Ach effluxes in the somatosensory cortex were detected using in vivo intracerebral microdialysis in freely moving rats. Once basal levels of Ach were stabilized, samples were collected every 20 minutes and measured by high-performance liquid chromatography. In the intraperitoneal group, propofol was cumulatively administered (10, 30, and 100 mg/kg) into the peritoneal cavity. In the microinjection groups, propofol (40 ng in 0.2 microL) was administered into the BF, the Pef, or the striatum (control), and the cortical changes in Ach efflux and EEG were observed for 2 hours. In another 14 rats, the sedative/anesthetic score was obtained after intraperitoneal, Pef, or striatal injection of propofol. The placement of the tip of the microdialysis probe and the microinjection tube was confirmed by histological examination. RESULTS: Intraperitoneal injection of propofol dose-dependently decreased the Ach efflux and induced light sedative to moderate anesthetic states. Loss of righting reflex was observed with significant increases in the relative alpha-power band at 100 mg/kg propofol. Microinjection of propofol into the BF significantly decreased the cortical Ach efflux to -40.2% + or - 19.9% at 40 to 60 minutes. However, there was no difference in the total Ach efflux for 2 hours between BF and control groups. In contrast, microinjection of propofol into the Pef immediately decreased the Ach efflux at 0 to 20 min and maximally to -59.3 + or - 20.4 at 100 to 120 minutes. The total Ach efflux in the Pef microinjection group was significantly less than that in the control group. The same dose of propofol injected into the Pef induced light to deep sedation. There was no significant change in the relative EEG power band between BF or Pef and control groups. CONCLUSION: The nuclei in the Pef are, at least in part, responsible for the sedative action of propofol in rats.

The effects of fibroblast growth factor-2 on rotator cuff reconstruction with acellular dermal matrix grafts.

PURPOSE: Our purpose was to determine whether the local application of fibroblast growth factor (FGF) 2 accelerates regeneration and remodeling of rotator cuff tendon defects reconstructed with acellular dermal matrix (ADM) grafts in rats. METHODS: Thirty adult male Sprague-Dawley rats were divided into equal groups undergoing FGF-treated and FGF-untreated repairs. All rats underwent placement of an ADM graft for the supraspinatus defect (3 x 5 mm). FGF-2 (100 microg/kg) in a fibrin sealant was applied to both shoulders in the FGF-treated group, whereas only fibrin sealant was applied in untreated group. At 2, 6, and 12 weeks after surgery, 5 rats (10 shoulders) in each group were sacrificed for histologic analysis (3 shoulders) and biomechanical testing (7 shoulders). The controls were 5 unoperated rats (3 histologic and 7 biomechanical control specimens). RESULTS: Unoperated control tendons inserted into the bone by direct insertion; there was a zone of fibrocartilage between the tendon and bone. At 2 weeks, the FGF-treated group had tendon maturing scores similar to those in the untreated group (P > .05). At 6 and 12 weeks, the FGF-treated group had significantly higher scores (P < .05). At 2 weeks, specimens in both the treated and untreated groups exhibited similar strength; the ultimate tensile failure load was 6.0 +/- 4.0 N and 5.8 +/- 2.0 N, respectively (P > .05). At 6 weeks, the FGF-treated specimens were stronger, with an ultimate tensile failure load of 10.2 +/- 3.1 N compared with 7.2 +/- 2.2 N in the untreated group (P = .02). At 12 weeks, the FGF-treated specimens were stronger, with an ultimate tensile failure load of 15.9 +/- 1.6 N compared with 13.2 +/- 2.0 N in the untreated group (P = .0072), and there were no significant differences in strength compared with the controls (17.8 +/- 2.6 N) (P > .05). CONCLUSIONS: The remodeling of ADM grafts placed in rat rotator cuff tendon defects was accelerated by the local administration of FGF-2. CLINICAL RELEVANCE: The application of FGF-2 may result in improved histologic characteristics and biomechanical strength in ADM graft constructs in humans.

The effect of a local application of fibroblast growth factor-2 on tendon-to-bone remodeling in rats with acute injury and repair of the supraspinatus tendon.

METHODS: We investigated the effect of application of fibroblast growth factor (FGF)-2 on the tendon-to-bone remodeling of repaired supraspinatus tendon in rats subjected to bilateral detachment. FGF-2 (100 mg/kg) in a fibrin sealant or sealant alone was applied on the right and left shoulders, respectively. Twelve animals each at 2, 4, and 6 weeks after surgery were sacrificed for histological analysis (n = 5) and biomechanical Q1 testing (n = 7). RESULTS: Histologically, at 2 weeks, FGF-treated specimens had significantly higher tendon-to-bone insertion maturing scores then untreated specimens (P < .002). At 4 and 6 weeks, the scores of FGF-treated and untreated specimens were similar (P > .05). Biomechanically, FGF-treated specimens were stronger at 2 weeks (P = .001); at 4 and 6 weeks, both specimens exhibited similar strength (P > .05). CONCLUSIONS: The initial tendon-to-bone remodeling was accelerated by a local application of FGF-2. This may represent a clinically important improvement in rotator cuff repair.

Differential responses of porcine anterior spinal and middle cerebral arteries to carbon dioxide and pH.

OBJECTIVE: Dysfunction of the anterior spinal arteries (ASAs) may induce paresis or paraplegia after thoracoabdominal aortic aneurysm or spine surgery. However, there have been no reports of the effects of CO2 and pH on ASAs. Information on these effects on ASAs might contribute to the perioperative management or critical care of spinal cord function. Thus, we investigated the effects of CO2 and pH on the vasomotor tone of ASAs and the third branch of the middle cerebral artery (bMCA). DESIGN: Prospective study of the effects of CO2 and pH on vasomotor response of porcine ASA and bMCA in vitro. SETTING: University laboratories. SUBJECTS: Porcine heads and spinal cords obtained from a slaughterhouse. INTERVENTION: ASAs and bMCAs were isolated, and changes in the intraluminal region of these pressurized arteries ( approximately 80 mm Hg) were observed for 30 minutes after perfusion with a solution saturated with various concentrations of CO2 and pH. MEASUREMENTS AND MAIN RESULTS: Respiratory acidosis (pH/Pco2 approximately 7.10-7.15/ approximately 60-80 mm Hg) constricted the ASAs, followed by a partial but gradual decrease in tone, whereas the bMCAs were exclusively dilated. The respiratory alkalosis (pH/Pco2 approximately 7.60/ approximately 20 mm Hg) did not influence ASA tone. Vasoconstriction of the ASAs induced by respiratory acidosis was abolished by removal of the endothelium, but not by N-nitro-L-arginine (1 microM). Respiratory acidosis dilated the ASAs in all preparations treated with ONO-3708 (1 microM), a specific thromboxane A2 receptor antagonist, and OKY-046 (1 microM), a specific thromboxane synthase inhibitor. Metabolic acidosis (pH/Pco2 approximately 7.10/ approximately 40 mm Hg) caused dilation of both bMCAs and ASAs, which was abolished by glibenclamide (1 microM). CONCLUSIONS: CO2-induced endothelium-dependent constriction in porcine ASAs through releasing thromboxane A2-like substance(s). Thus, hypercarbia might not be favorable for the perioperative or critical care management of spinal cord function during thoracoabdominal aortic aneurysm and spine surgery.

A new approach for observing cerebral cisterns and ventricles via a percutaneous lumbosacral route by using fine, flexible fiberscopes.

OBJECT: To establish a new method for the diagnosis of central nervous system diseases, the authors visualized the cerebral cisterns and ventricles via a percutaneous lumbosacral route by using newly developed fine, flexible fiberscopes. METHODS: Fine, flexible fiberscopes, 0.9 and 1.4 mm in diameter, were introduced up to the cerebral cisterns and ventricles through a percutaneous lumbosacral route in awake patients with chronic headache and/or neck pain or those undergoing spinal surgery and in whom MR imaging did not disclose any particular abnormalities in the brain. A lumbosacral subarachnoid puncture was made with a modified method of a continuous epidural block. RESULTS: In 25 of 31 patients tested, the cerebellomedullary and/or pontine/interpeduncular cisterns were easily and safely reached, and the brainstem structures were visualized. Advancement of the fiberscope beyond the spinal level was abandoned in 6 patients with adhesive spinal arachnoiditis, because the fiberscopes encountered resistance seemingly caused by arachnoid adhesions. Further advancement of the fiberscopes up to the fourth and third ventricles was successfully achieved in 2 patients. A number of arachnoid filaments were found in the cerebellomedullary cistern in 4 patients: 2 with chronic spinal arachnoiditis, 1 with a spinal arachnoid cyst, and 1 with posttraumatic pain syndrome. None of the patients reported pain or any major complication except a postspinal headache and light fever, which were encountered in 4 and 1 patient, respectively. CONCLUSIONS: The approach to the supraspinal structures via the lumbosacral route by using a fine, flexible fiberscope may provide a new, minimally invasive, and safe way to observe the cerebral cisterns and/or brainstem regions.