Impact of the Lumbar Arteries on Aneurysm Diameter and Type 2 Endoleak after Endovascular Aneurysm Repair.

BACKGROUND: Prophylactic embolization of the inferior mesenteric artery (IMA) during endovascular aneurysm repair (EVAR) is recommended to prevent type 2 endoleak (T2EL). However, the impact of patent lumbar arteries (LAs) on T2ELs and aneurysm diameter has not been elucidated. METHODS: Fifty-seven consecutive patients who underwent EVAR at our institution between January 2013 and September 2022 and whose IMA had been occluded preoperatively or newly occluded postoperatively were included in the study. Predictive factors for aneurysm sac enlargement, sac shrinkage, and T2EL were investigated. RESULTS: T2ELs occurred in 22.8% of the patients. The 4-year cumulative incidence rates of sac enlargement and shrinkage were 6.7% and 64.6%, respectively. The number of postoperative patent LAs was identified as a risk factor for T2ELs (95% confidence interval [CI]: 1.54-12.7, P = 0.0065). The number of postoperative patent LAs was found to be a significant predictor of sac enlargement (adjusted hazard ratio [AHR] 3.15, 95% CI: 1.43-6.96, P = 0.0045) and shrinkage (AHR 0.63, 95% CI: 0.43-0.91, P = 0.014). CONCLUSIONS: The current study demonstrated that the number of postoperative patent LAs had a significant impact on the development of T2ELs and the change in aneurysm diameter in patients in whom the IMA was occluded after EVAR.

Inhaled nitric oxide improves pulmonary hypertension and organ functions after adult heart valve surgeries.

OBJECTIVES: Pulmonary hypertension during cardiac surgery is associated with increased morbidity and mortality. Inhaled nitric oxide serves as a selective pulmonary vasodilator and has other potential extrapulmonary protective roles. Its effects on pulmonary hypertension and organ functions after adult valve surgeries were evaluated. METHODS: From April 2017 to March 2000, 30 patients received inhaled nitric oxide therapy for pulmonary hypertension during weaning from cardiopulmonary bypass in valvular surgery (iNO group). The group was compared with a control group of 65 patients who developed pulmonary hypertension during weaning from cardiopulmonary bypass in valvular surgery and received conventional therapy from April 2014 to March 2017. Intraoperative hemodynamic changes and postoperative Sequential Organ Failure Assessment (SOFA) score were evaluated. RESULTS: The inhalation of nitric oxide lowered the pulmonary-to-systemic pressure ratio (Pp/Ps) (p < 0.0001) in the iNO group, and this ratio after the inhalation was significantly lower than that in the control group (p = 0.015). Moreover, norepinephrine requirement was lower in the iNO group than in the control group (p = 0.0060). The SOFA total scores, respiratory scores, coagulation scores, and the increase of renal scores within postoperative 2 days were lower in the iNO group than in the control group (p < 0.0001, p = 0.0002, p = 0.0013, and p = 0.037). CONCLUSIONS: Inhaled nitric oxide therapy ameliorated pulmonary hypertension and improved postoperative respiratory, coagulation, and renal functions in adult valve surgeries.

The provisional extension to induce complete attachment technique is associated with abdominal aortic remodeling and reduces aorta-related adverse events after aortic dissection.

OBJECTIVE: This study evaluated the efficacy of the provisional extension to induce complete attachment (PETTICOAT) technique for type B and postoperative residual type B aortic dissections compared with the conventional thoracic endovascular aortic repair (TEVAR) technique. METHODS: In this retrospective study, we compared sequential aortic morphologic changes in consecutive patients with type B and postoperative residual type B aortic dissections treated with the PETTICOAT technique between January 2016 and December 2017 with patients treated with the conventional TEVAR between January 2013 and December 2015. Outcomes included aortic remodeling and aorta-related adverse events for 2 years postoperatively. RESULTS: Forty-eight patients were included in this study (24 in the PETTICOAT group, 24 patients in the conventional TEVAR group). Although both groups showed aortic remodeling in the descending thoracic aorta, the PETTICOAT group developed significantly better aortic remodeling in the abdominal aorta compared with the conventional TEVAR group during the observation period. The PETTICOAT group had significantly fewer aorta-related adverse events compared with the conventional TEVAR group (8% vs 54%; P < .001). Aorta-related adverse events more commonly occurred in the poor remodeling group compared with in the good remodeling group (P = .001; hazard ratio, 8.32; 95% confidence interval, 2.26-30.64). CONCLUSIONS: This study suggests that the PETTICOAT technique for aortic dissection may promote aortic remodeling and decrease the incidence of aorta-related adverse events. Additional studies are required to confirm these preliminary findings.

Full PETTICOAT in acute type B aortic dissection with patent false lumen may offer positive remodeling for the distal aorta.

OBJECTIVE: The provisional extension to induce complete attachment (PETTICOAT) technique is a unique thoracic endovascular aortic repair (TEVAR) for aortic dissection, which consists of proximal descending aortic endografting plus distal bare-metal stenting. This study aimed to investigate the efficacy of the PETTICOAT technique in patients with acute-sub-acute complicated type B aortic dissections. In particular, we compared the remodeling effect of full PETTICOAT covering down to the abdominal aorta with that of simple entry closure. METHODS: In this retrospective pre-post study, we compared the clinical course of consecutive patients undergoing TEVAR with the PETTICOAT technique in which proximal entry tear was excluded with a covered stent, and extension bare stents were placed down to the abdominal segment for acute-sub-acute complicated type B aortic dissections, between 2015 and 2017, with a control group treated with TEVAR with entry closure between 2011 and 2015. Outcomes included the aortic remodeling rate and the aortic diameter up to 1 year after surgery. RESULTS: Subjects consisted of 47 patients (21 in full PETTICOAT group, 26 in the simple entry closure group). The remodeling rate of the abdominal aorta in the full PETTICOAT group was significantly higher than in the simple entry closure group (p < 0.05), while that of the thoracic aorta was comparable between the two groups. CONCLUSIONS: This study suggests that the full PETTICOAT technique achieves better aortic remodeling compared to entry closure alone, and might lead to less reintervention.

Outflow of N-butyl-2-cyanoacrylate into the Pancreatic Duct: Transcatheter Arterial Embolization for Hemosuccus Pancreaticus.

A 54-year-old Japanese woman, hospitalized for recurrent chronic alcoholic pancreatitis, manifested bloody stools. An esophagogastroduodenoscopy revealed active bleeding from the papilla of Vater. Contrast-enhanced computed tomography (CECT) revealed a pseudoaneurysm in the pancreatic pseudocyst (hemosuccus pancreaticus). Angiography demonstrated pseudoaneurysm of the dorsal pancreatic artery branch. We selected N-butyl-2-cyanoacrylate (NBCA) as an embolus material because of the existing coagulopathy and difficulty in selecting the arterial branch. The administered NBCA outflowed into the pancreatic duct over the pseudoaneurysm. However, transcatheter arterial embolization (TAE) was successful, and no complication or rebleeding was observed after TAE. CECT showed NBCA cast in the pancreatic duct; however, the chronic pancreatitis improved. NBCA may be used to regulate hemosuccus pancreaticus in emergency settings; however, interventional radiologists must carefully consider the complications caused by NBCA.

Hypertrophic obstructive cardiomyopathy and mitral regurgitation in Libman-Sacks endocarditis.

Hypertrophic obstructive cardiomyopathy in Libman-Sacks endocarditis is quite rare and the correct etiological relationship between them is unknown. Some changes may cause a secondary disorganization of the ordinary muscle structure, making a disarray pattern with irregular interwoven myocyte fibers. This case report describes one of the first cases of ventricular septal myectomy and mitral valve replacement for hypertrophic obstructive cardiomyopathy and mitral valve regurgitation associated with Libman-Sacks endocarditis.

Transcatheter arterial embolization for initial hemostasis in a hemodynamically unstable patient with mesenteric hemorrhage: A case report.

Surgical treatment of mesenteric injuries is necessary to control hemorrhage, manage bowel injuries, and evaluate bowel perfusion. It has recently been suggested that some patients can be managed with transcatheter arterial embolization (TAE) for initial hemostasis. We present a hemodynamically unstable patient who was initially managed by TAE for traumatic mesenteric hemorrhage. A 60-year-old man was injured in a motor vehicle accident and transported to our facility. On arrival, the patient was hemodynamically stable, and had abdominal pain. Physical examination revealed a seatbelt sign on the lower abdomen. A contrast-enhanced computed tomography (CT) scan showed intra-abdominal hemorrhage, mesenteric hematoma, and a giant-pseudoaneurysm, but no intra-abdominal free air or changes in the appearance of the bowel wall. After the CT scan, his vital signs deteriorated and surgical intervention was considered, but TAE was performed to control the hemorrhage. After TAE, the patient was hemodynamically stable and had no abdominal tenderness. A follow-up CT scan was performed 2 days later which showed partial necrosis of the transverse colon and some free air. Resection of the injured transverse colon with primary anastomosis was performed. The patient improved and was discharged 35 days after injury. TAE can be effective as the initial hemostatic procedure in patients with traumatic mesenteric hemorrhage.

Atraumatic splenic rupture in a peritoneal dialysis patient.

Splenic hemorrhage is a potentially life-threatening complication usually occurring after blunt trauma to the abdomen. Atraumatic splenic rupture (ASR) is an uncommon condition, and mostly results from pathology affecting the spleen, such as tumor infiltration or infection. Here, we report a case of atraumatic rupture of a normal spleen in a patient undergoing peritoneal dialysis, and review similar cases in the literature. The case involved a 58-year-old man with nephrotic syndrome who had been undergoing peritoneal dialysis for 1 year. He presented to the hospital with abdominal pain, nausea, and blood-stained dialysate. Laboratory data revealed severe anemia, with a hemoglobin of 4.3 g/dL. An abdominal computed tomography (CT) scan demonstrated a high-density area around the spleen and malposition of the catheter. Laparoscopy revealed large amounts of coagulated blood surrounding the spleen. The patient was diagnosed with atraumatic splenic bleeding. He improved with bed rest and blood transfusion, and could continue with peritoneal dialysis. It was considered that the etiology of bleeding was directly from the spleen. However, due to the temporary malposition of the peritoneal catheter, catheter-induced splenic trauma could not be ruled out. ASR is a rare entity that needs a high index of suspicion for diagnosis. Using CT scanning and peritoneal fluid analysis, these modalities may assist in the diagnosis. Emergency intervention is required upon definitive diagnosis. Increased awareness of ASR can enhance the early diagnosis and effective treatment.

Stepwise Total Aortic Repairs With Fenestrated Endografts in a Patient With Loeys-Dietz Syndrome.

Loeys-Dietz syndrome (LDS) is a rare connective tissue disorder (CTD) caused by mutations in the gene encoding transforming growth factor-ß receptors Ⅰ and Ⅱ. Patients with LDS manifest spontaneous aneurysms and dissections of the aorta and peripheral artery. We report a successful treatment with a hybrid endovascular repair for a rapidly expanding thoracoabdominal aneurysm in a 41-year-old woman affected by LDS. To overcome the difficulties of anatomical and surgical repair, we applied an original strategy using surgeon-modified fenestrated endografts.

A multi-institutional survey of interventional radiology for type II endoleaks after endovascular aortic repair: questionnaire results from the Japanese Society of Endoluminal Metallic Stents and Grafts in Japan.

PURPOSE: To investigate the current status of interventional radiology (IR) procedures for a type II endoleak (T2EL) in Japan, and to identify the technical aspects that affect treatment results. MATERIALS AND METHODS: A retrospective survey was conducted by distributing questionnaires to 25 institutions. The eligibility criteria were endovascular aortic repair (EVAR) performed using commercial stent grafts and IR performed for T2EL between January 2007 and December 2013. Technical success was defined as disappearance of the EL on digital subtraction angiography immediately after embolization, and imaging success was defined as no EL on contrast-enhanced computed tomography within 6 months. Statistical comparisons of the number of involved branches, embolization level, embolic material, and changes in aneurysm size were made between the imaging success and imaging failure groups. The technical and imaging success rates were also compared between the initial therapy and repeat groups. RESULTS: A total of 166 cases were investigated. Initial therapy was performed in 147 cases (88.6 %), with repeat therapy in 19 cases (11.4 %). Transcatheter arterial embolization (TAE) was used most frequently, in 161 cases (97 %), with direct puncture (DP) used in 5 cases (3 %). Both coil embolization for the branches and NBCA embolization for the sac were frequently chosen. The technical success rate was 83.2 % (TAE group), and the imaging success rate was 46.5 % (TAE + DP groups). Branch + sac embolization was performed more frequently in the imaging success group. There was no significant difference in the number of involved branches or embolic material between the imaging success and imaging failure groups. Enlargement of the aneurysm was more frequently seen in the imaging failure group. There were no significant differences in the technical success and imaging success rates between the initial therapy and repeat groups. CONCLUSION: This is the first report of a multi-institutional questionnaire survey of IR procedures for T2EL after EVAR in Japan that was conducted to determine the current status. Enlargement of aneurysm size after embolization was more frequently seen in the imaging failure group. It is important to embolize both branch and sac to achieve imaging success, regardless of embolic material. Long-term outcomes need to be investigated.

Early CT signs in out-of-hospital cardiac arrest survivors: Temporal profile and prognostic significance.

AIM: Although computed tomography (CT) signs of ischaemia, including loss of boundary (LOB) between grey matter and white matter and cortical sulcal effacement, in cardiac arrest (CA) survivors are known, their temporal profile and prognostic significance remains unclear; their clarification is necessary. METHODS: Brain CT scans were obtained immediately after resuscitation in 75 non-traumatic CA survivors in a prospective fashion. They were divided into two groups according to the CA-return of spontaneous circulation (ROSC) interval: < or =20 min vs. >20 min. The incidence of the CT signs and predictability of these signs for outcome, assessed 6 months after CA, was evaluated and compared. RESULTS: The incidence of the positive LOB sign was 24% in the < or =20-min group and 83% in the >20-min group, and the difference was statistically significant (p<0.001). The interval of 20 min seemed to be the time window for the LOB development. The incidence of the positive sulcal effacement sign was 0% in the < or =20 min group and 34% in the >20-min group, and the difference was statistically significant (p=0.004). A positive LOB sign was predictive of unfavourable outcome with an 81% sensitivity and 92% specificity. A positive sulcal effacement sign was predictive of unfavourable outcome with a 32% sensitivity and 100% specificity. CONCLUSION: A time window may exist for ischaemic CT signs in CA survivors. The LOB sign may develop when the CA-ROSC interval exceeds 20 min, whereas the sulcal effacement sign may develop later. However, their temporal profile and outcome predictability should be verified by multicentre studies.

Recent independent evolution of msp1 polymorphism in Plasmodium vivax and related simian malaria parasites.

The Plasmodium MSP-1 is a promising malaria vaccine candidate. However, the highly polymorphic nature of the MSP-1 gene (msp1) presents a potential obstacle for effective vaccine development. To investigate the evolutionary history of msp1 polymorphism in P. vivax, we construct phylogenetic trees of msp1 from P. vivax and related monkey malaria parasite species. All P. vivax msp1 alleles cluster in the P. vivax lineage and are not distributed among other species. Similarly, all P. cynomolgi msp1 alleles cluster in the P. cynomolgi lineage. This suggests that, in contrast to presumed ancient origin of P. falciparum msp1 polymorphism, the origin of P. vivax msp1 polymorphism is relatively recent. We observed positive selection in the P. vivax lineage but not in P. cynomolgi. Also, positive selection acts on different regions of msp1 in P. vivax and P. falciparum. This study shows that the evolutionary history of msp1 differs greatly among parasite lineages.

Role of asymmetrical dimethylarginine in renal microvascular endothelial dysfunction in chronic renal failure with hypertension.

We examined whether endothelial function of the renal microcirculation was impaired in a model of chronic renal failure (CRF), and further assessed the role of asymmetrical dimethylarginine (ADMA) and its degrading enzyme, dimethylarginine dimethylaminohydrolase (DDAH), in mediating the deranged nitric oxide (NO) synthesis in CRF. CRF was established in male mongrel dogs by subtotal nephrectomy, and the animals were used in experiments after a period of 4 weeks. The endothelial function of the renal afferent and efferent arterioles was evaluated according to the response to acetylcholine, using an intravital needle-lens charge-coupled device camera. Intrarenal arterial infusion of acetylcholine (0.01 microg/kg/min) elicited 22+/-2% and 20+/-2% dilation of the afferent and efferent arterioles in normal dogs. In dogs with CRF, this vasodilation was attenuated (afferent, 12+/-2%; efferent, 11+/-1%), and the attenuation paralleled the diminished increments in urinary nitrite+nitrate excretion. In the animals with CRF, plasma concentrations of homocysteine (12.2+/-0.7 vs. 6.8+/-0.4 micromol/l) and ADMA were elevated (2.60+/-0.13 vs. 1.50+/-0.08 micromol/l). The inhibition of S-adenosylmethionine-dependent protein arginine N-methyltransferase by adenosine dialdehyde decreased plasma ADMA levels, and improved the acetylcholine-induced changes in urinary nitrite+nitrate excretion and arteriolar vasodilation. Acute methionine loading impaired the acetylcholine-induced renal arteriolar vasodilation in CRF, but not normal dogs, and the impairment in CRF dogs coincided with the changes in plasma ADMA levels. Real-time polymerase chain reaction revealed downregulation of the mRNA expression of DDAH-II in the dogs with CRF. Collectively, these results provide direct in vivo evidence of endothelial dysfunction in canine CRF kidneys. The endothelial dysfunction was attributed to the inhibition of the NO production by elevated ADMA, which involved the downregulation of DDAH-II. The deranged NO metabolic pathway including ADMA and DDAH is a novel mechanism for the aggravation of renal function.

Cervical peridural calcification in patients undergoing long-term hemodialysis. Report of two cases.

The authors report on two patients undergoing long-term hemodialysis in whom cervical myelopathy was caused by calcification related to the cervical dural sac. The lesions were demonstrated on plain computerized tomography (CT) scans as dotted curvilinear bands outlining the dural sacs in almost the whole of their cervical spines. During posterior decompressive surgery in both cases, the CT scanning--documented curvilinear bands were identified as calcified plaques infiltrating the fibrous membranes beneath the ligamenta flava, constricting the cervical dural tube. In each case, the spinal cord could not be decompressed by merely enlarging the osseous spinal canal; rather, it required removal of the calcified membrane from the posterior surface of the dura. Based on the operative findings, the lesion should be described as cervical peridural calcification.

Role of endothelium-derived hyperpolarizing factor in ACE inhibitor-induced renal vasodilation in vivo.

Although the angiotensin-converting enzyme (ACE) inhibitor-induced bradykinin enhances nitric oxide (NO) release, bradykinin may also stimulate the production of an additional vasodilator, endothelium-derived hyperpolarizing factor (EDHF). This study examined the role of EDHF in mediating the NO-independent action of ACE inhibitors in canine renal microcirculation in vivo. We used intravital CCD camera videomicroscopy that allowed direct visualization of renal microcirculation in superficial and juxtamedullary nephrons in an in vivo, in situ, and relatively intact setting. In the presence of E4177 (an angiotensin receptor blocker), cilazaprilat (30 microg/kg) had no effect on diameter of superficial afferent arterioles (Aff), but it increased renal contents of bradykinin and nitrate plus nitrite, and it elicited dilation of juxtamedullary Aff (from 24.0+/-0.2 to 28.2+/-0.8 microm), juxtamedullary efferent arterioles (Eff) (from 24.2+/-0.2 to 28.0+/-0.8 microm), and superficial Eff (from 18.2+/-0.2 to 19.7+/-0.2 microm). These changes in diameters were prevented by N(alpha)-adamantaneacetyl-d-Arg-[Hyp(3),Thi(5,8),D-Phe(7)]bradykinin, a bradykinin receptor antagonist. The pretreatment with nitro-l-arginine methylester (l-NAME) plus E4177 eliminated the dilator response of juxtamedullary/superficial Eff and the increase in renal nitrate plus nitrite levels induced by cilazaprilat. In contrast, in the presence of E4177+l-NAME, cilazaprilat still caused 8%+/-3% dilation of juxtamedullary Aff, which was completely eliminated by proadifen, a cytochrome-P450 and K(Ca) channel blocker. Collectively, the ACE inhibitor exerts multiple vasodilator mechanisms, including the inhibition of angiotensin II formation; blockade of angiotensin II activity appears to be a dominant mechanism in superficial Aff, whereas the bradykinin-induced NO acts on superficial Eff and juxtamedullary Aff/Eff. Furthermore, a putative EDHF is an additional mechanism for the ACE inhibitor-induced vasodilation of juxtamedullary Aff in vivo.

Role of a critical pathway for door-to-CT-completion interval in the management of acute ischemic stroke patients in the emergency room.

OBJECTIVE: Door-to-CT-completion interval (DCI) for acute ischemic stroke patients is one of the clinical indicators of quality assurance in an emergency room (ER). The aim was to clarify whether the critical pathway improves the DCI for acute stroke patients in the ER. METHODS: The pathway describes each step in patient evaluation in sequence from the patient's arrival in the ER until the brain CT is completed. Whether to use the pathway when evaluating individual patients is left to the discretion of the physician. After excluding 8 cases with insufficient data, 52 cases diagnosed with acute stroke (29 males, 69.9 +/- 12.4 y/o) in the ER between January and February 2003 were retrospectively identified. A logistic regression analysis was used to assess the impact of application of the pathway on achievement of an acceptable DCI (<25 min). RESULTS: The pathway was applied in 21.2% of the cases included in the study, and the median DCI was reduced from 48 minutes to 22 minutes as a result (P=0.02). Comparing them with the DCI, the probability values for ambulance use, consciousness disturbance, history of stroke, and application of the pathway in univariate analyses were less than 0.10. These variables were entered into the logistic analysis, which that indicated application of the pathway was the strongest variable related to acceptable DCI (OR: 10.92, 95% CI: 1.22 to 97.96). CONCLUSION: Application of the pathway was associated with an improvement of the DCI. Use of the pathway will improve the quality of the process of care in the ER.

Expression of heat shock protein 72 in rat quadriceps muscles following anterior cruciate ligament resection.

This study investigated the expression of heat shock protein 72 (HSP 72) in quadriceps femoris muscle following anterior cruciate ligament (ACL) resection and running training in rats. A group of 15 Wistar strain male rats (10 weeks old) were divided into three groups: sham-operated (S), ACL resection (A), and running training following ACL resection (R). In the A and R groups, the ACL of the right knee was resected using microsurgical techniques. Rats in the R group were subjected to running training for 9 weeks on a motor-driven treadmill for rodents 1 week after ACL resection. At 10 weeks after ACL resection, glycerinated single fibers were prepared from vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), and semimembranosus (SM) muscles. To determine the levels of HSP72 (HSP-inducible) in each muscle, we used the Western blotting technique. HSP72 expression in VL and VM increased following ACL resection ( P < 0.05) but not in RF or SM. Exercise training caused an elevation in HSP72 expression in VL and VM. There were no significant changes in HSP72 expression in RF or SM following exercise training. These results suggest that some stress would be generated by ACL resection in VM and VL and might cause atrophy in VM and VL.

[Is intravenous contrast enhancement effective in improving CT diagnosis of hepatic disease?].

PURPOSE: The purpose of this study was to evaluate the effectiveness of contrast enhancement in the diagnosis of hepatic disease. MATERIALS AND METHODS: 2761 cases involving CT of the liver and abdomen were analyzed using logistic analysis. CT was either helical-CT (SDCT) or multi-detector CT (MDCT), with power injector. RESULTS: Contrast enhancement use was 92% in liver disease and 95% in tumor cases. A typical case involved a 66-year-old man given 2-4 ml/sec of contrast material using dual injection. CT imaging was done in the equilibrium stage. The use of contrast material was effective for the diagnosis of liver tumor except in the qualitative diagnosis of hepatocellular carcinoma with SDCT where the odds ratio was 0.084. CONCLUSION: Intravenous contrast enhancement was effective for the CT diagnosis of hepatic tumor. Dynamic CT was effective using MDCT, and dual injection of contrast material was also valid for SDCT. Multiphasic studies were needed for detecting liver tumors not only on MDCT but also on SDCT. CT imaging during the equilibrium phase alone is inadequate to document diagnosis of metastatic liver tumors. The addition of various phasic contrast materials during CT was effective in evaluating liver tumors that showed angiogenesis.

Profiles of connectin (titin) in atrophied soleus muscle induced by unloading of rats.

Responses of the properties of connectin molecules in the slow-twitch soleus (Sol) and fast-twitch extensor digitorum longus muscles of rats to 3 days of unloading with or without 3-day reloading were investigated. The wet weight (relative to body wt) of Sol, not of extensor digitorum longus, in the unloaded group was significantly less than in the age-matched control (P < 0.05). Immunoelectron microscopic analyses showed that a monoclonal antibody against connectin (SM1) bound to the I-band region close to the edge of the A band at resting length and moved reversibly away from the Z line as the muscle fibers were stretched. In Sol, the displacement of the SM1-bound dense spots in response to stretching decreased after hindlimb suspension. There were no changes in the molecular weights and the percent distributions of alpha- and beta-connectin in both muscles after hindlimb suspension. A significant increment of percent beta-connectin in Sol was observed after 3 days of reloading after hindlimb suspension (P < 0.05). It is suggested that the elasticity of connectin filaments in the I-band region of the atrophied Sol fibers was reduced relative to that of the control fibers. The lack of the elasticity in atrophied muscle fibers may cause a decrease in contractile function.

Role of nitric oxide and prostaglandin E2 in acute renal hypoperfusion.

Although acute renal ischaemia alters the production of various paracrines, there has been little investigation examining the role of intrarenal vasoactive substances. In the present study, we investigated the role of intrarenal nitric oxide and prostaglandins in modulating the acute renal hypoperfusion-induced alterations in renal function. After a 90% clipping of the left renal artery for 60 min, the clip was released, and the renal haemodynamics and sodium excretion were evaluated in both clipped and non-clipped kidneys of anaesthetized dogs. Furthermore, the changes in renal contents of nitrate/nitrite (NOx) and prostaglandin E2 (PGE2) were assessed by using the renal microdialysis technique. The release of the clipping elicited a gradual recovery of renal plasma flow and glomerular filtration rate, and a sustained increase in fractional sodium excretion (FENa) in the clipped kidney. Renal interstitial NOx was reduced in both the cortex (from 8.2 +/- 1.1 to 2.5 +/- 0.3 micromol/L, P < 0.01) and medulla (from 10.1 +/- 0.9 to 3.1 +/- 0.2 micromol/L, P < 0.01), but the levels gradually elevated after declamping. The treatment with nitro-l-arginine methylester only modestly impaired the recovery of renal plasma flow (RPF; at hour 4) and glomerular filtration rate (GFR; at hours 3 and 4 after declamping), without affecting FENa. Conversely, the renal PGE2 levels increased prominently upon the onset of ischaemia (medulla, from 149 +/- 19 to 378 +/- 39 pg/mL, P < 0.01; cortex, from 107 +/- 13 to 302 +/- 34 pg/mL, P < 0.01). Furthermore, the pretreatment with a non-specific cyclo-oxygenase (COX) inhibitor, sulpyrine, and a COX-2-specific inhibitor, NS398, prominently inhibited the increases in FENa induced by the acute renal arterial clipping in a similar manner. In conclusion, in acute renal hypoperfusion, nitric oxide (NO) plays a permissive role in the recovery of the renal haemodynamics. In contrast, sustained increases in renal PGE2 in both clipped and non-clipped kidneys indicate that the COX-2-mediated PGE2 contributes importantly to the failure of the sodium reabsorption in response to acute renal hypoperfusion.