Seroprevalence of hepatitis E virus in dromedary camels, Bedouins, Muslim Arabs and Jews in Israel, 2009-2017.

Hepatitis E virus (HEV) is an emerging cause of viral hepatitis worldwide. Recently, HEV-7 has been shown to infect camels and humans. We studied HEV seroprevalence in dromedary camels and among Bedouins, Arabs (Muslims, none-Bedouins) and Jews and assessed factors associated with anti-HEV seropositivity. Serum samples from dromedary camels (n = 86) were used to determine camel anti-HEV IgG and HEV RNA positivity. Human samples collected between 2009 and 2016 from >20 years old Bedouins (n = 305), non-Bedouin Arabs (n = 320) and Jews (n = 195), were randomly selected using an age-stratified sampling design. Human HEV IgG levels were determined using Wantai IgG ELISA assay. Of the samples obtained from camels, 68.6% were anti-HEV positive. Among the human populations, Bedouins and non-Bedouin Arabs had a significantly higher prevalence of HEV antibodies (21.6% and 15.0%, respectively) compared with the Jewish population (3.1%). Seropositivity increased significantly with age in all human populations, reaching 47.6% and 34.8% among ⩾40 years old, in Bedouins and non-Bedouin Arabs, respectively. The high seropositivity in camels and in ⩾40 years old Bedouins and non-Bedouin Arabs suggests that HEV is endemic in Israel. The low HEV seroprevalence in Jews could be attributed to higher socio-economic status.

The value of postoperative anticoagulants to improve flap survival in the free radial forearm flap: a systematic review and retrospective multicentre analysis.

BACKGROUND: Free radial forearm flap (FRFF) reconstruction is a valuable technique in head and neck surgery, which allows closure of large defects while striving to maintain functionality. Anticoagulative drugs are often administered to improve flap survival, although evidence regarding effectiveness is lacking. OBJECTIVE OF REVIEW: To investigate the effectiveness of postoperative anticoagulants to improve survival of the FRFF in head and neck reconstruction. TYPE OF REVIEW: Systematic review and multicentre, individual patient data meta-analysis. SEARCH STRATEGY: MEDLINE, EMBASE, Web of Science and CINAHL were searched for synonyms of 'anticoagulants' and 'free flap reconstruction'. EVALUATION METHOD: Studies were critically appraised for directness of evidence and risk of bias. Authors of the highest quality publications were invited to submit their original data for meta-analysis. RESULTS: Five studies were of adequate quality, and data from four studies (80%) were available for meta-analysis, describing 759 FRFF procedures. Anticoagulants used were as follows: aspirin (12%), low molecular weight dextran (18.3%), unfractioned heparin (28.1%), low molecular weight heparin (49%) and prostaglandin-E1 (2.1%). Thirty-one per cent did not receive anticoagulants. Flap failure occurred in 40 of 759 patients (5.3%) On univariate analysis, use of unfractioned heparin was associated with a higher rate of flap failure. However, these regimens were often administered to patients who had revision surgery of the anastomosis. In multivariate logistic regression analysis, anticoagulant use was not associated with improved flap survival or flap-related complications. CONCLUSIONS: The studied anticoagulative drugs did not improve FRFF survival or lower the rate of flap-related complications. In addition, some anticoagulants may cause systemic complications.

Enhanced characterization of serum autoantibody reactivity following HSP 60 immunization in a rat model of experimental autoimmune glaucoma.

PURPOSE: Antibodies against heat shock proteins have been identified in sera of human glaucoma patients in several studies and immunization with heat shock protein 60 (HSP 60) causes retinal ganglion cell (RGC) loss in an animal model of experimental autoimmune glaucoma. The aim of this study was to observe the time course of increased anti-retina antibody appearance in the serum and characterize the identification of prominent autoantibodies that accompany HSP 60 immunization in a rat model of experimental autoimmune glaucoma. METHODS: Eight weeks after immunization with HSP 60 retinal flatmounts were prepared and RGCs were counted in eight predefined areas and compared to controls. Serum collected before, as well as four and eight weeks after, immunization was used to detect antibody patterns against bovine retinal antigens using Western blotting techniques. These patterns were analyzed by multivariate statistical methods. Autoantibodies that were prominently increased were further identified through mass spectrometry. Intraocular pressure was measured throughout the study. RESULTS: After eight weeks, animals immunized with HSP 60 showed significant RGC loss of retinal flatmounts (P = 0.02), which was intraocular pressure independent. Early changes in antibody profiles, many of them significant upregulations, were detected. Antigens with significantly upregulated antibody reactivity after four weeks were identified as histone H2B type 1, S-arrestin, glial fibrillary acidic protein, vimentin, and heat shock protein 60. These upregulated autoantibodies returned to normal levels four weeks following their initial upregulation. Antibodies against retinaldehyde binding protein 1 on the other hand became upregulated after eight weeks. CONCLUSION: This is the first study to identify the appearance and disappearance of retinal autoantibodies in the serum of rats at several time-points following their initial upregulation in response to HSP 60 immunization in a model of experimental autoimmune glaucoma.

Functional characterization of a human aquaporin 0 mutation that leads to a congenital dominant lens cataract.

The aquaporin (AQP) transmembrane proteins facilitate the movement of water across the plasma membrane. In the lens, AQP0 is expressed in fiber cells and AQP1 in the epithelium. Recently, two individuals were identified with congenital polymorphic autosomal dominant cataract, due to a single nucleotide base deletion mutation in the lens AQP0. The deletion modified the reading frame resulting in the addition of a premature stop codon. In the present study, we examined the water permeability properties, trafficking and dominant negative effects as well as cytotoxicity due to the mutant AQP0 (Delta213-AQP0) protein. The membrane water permeability (P(w)) of Delta213-AQP0 expressing oocytes (14+/-1 microm/s) was significantly lower than those expressing WT-AQP0 (25+/-3 microm/s). P(w) of water injected control oocytes was 13+/-2 microm/s. Co-expression of WT-AQP0 with Delta213-AQP0 significantly lowered the P(w) (18+/-3 microm/s) compared to WT-AQP0. With or without the EGFP tag, WT-AQP0 protein localized in the plasma membranes of oocytes and cultured cells whereas Delta213-AQP0 was retained in the ER. Forster Resonance Energy Transfer (FRET) showed that WT-AQP0 partly localized with the co-expressed Delta213-AQP0. Co-localization studies suggest that the mutant AQP0 gained its dominant function by trapping the WT-AQP0 in the ER through hetero-oligomerization. Incubating the cells with chemical chaperones, namely, TMAO and DMSO, did not correct the folding/trafficking defects. Cell death in the Delta213-AQP0 expressing cells was due to necrosis caused by the accumulation of Delta213-AQP0 protein in the ER in cytotoxic proportions. The data show that replacement of the distal end of the 6th TM domain and the C-terminal domain of AQP0 due to the deletion mutation resulted in the impairment of cell membrane P(w), localization of the mutant protein in the ER without trafficking to the plasma membrane, and cytotoxicity due to the accumulation of the mutant protein. Cataracts in patients with this mutation might have resulted from the above mentioned consequences.

Radial forearm osteocutaneous free flap in maxillofacial and oromandibular reconstructions.

OBJECTIVES/HYPOTHESIS: The radial forearm osteocutaneous free flap is an excellent reconstructive modality for oromandibular and maxillofacial reconstruction in certain well-defined circumstances. The initial concern over donor site morbidity and the ability of the bone to reconstruct mandibular defects have led to only a few published series. STUDY DESIGN: Retrospective study of the experience of two tertiary medical centers with radial forearm osteocutaneous free flap. METHODS: Retrospectively, 52 patients were studied who underwent radial forearm osteocutaneous free flap reconstruction for cancer (49 cases) and trauma (3 cases). Bone length and skin paddle harvested, general morbidity (hematoma, wound infection, and dehiscence), recipient site morbidity (nonunion of neomandible, flap failure, and bone or plate exposure), and donor site morbidity (radius bone fracture, plate exposure, and skin graft failure) were reviewed. RESULTS: The average skin paddle size was 55.1 cm (range, 15-112 cm). The average radius bone harvest length was 6.3 cm (range, 2.5-11 cm). Donor site complications included tendon exposure (3 cases), radius bone fracture (1 case), and exposure of the plate (0). Recipient site complications included nonunion of the mandible (4), exposed mandible (1), exposed mandibular plates (2), exposed maxillary plates or bone (0), venous compromise (1), and flap failure (1). Two patients had perioperative deaths. CONCLUSION: Radial forearm osteocutaneous free flap is a valuable and viable option for oromandibular and maxillofacial reconstruction.

Alterations in the morphology of lamina cribrosa pores in glaucomatous eyes.

AIMS: To determine alterations which occur in the size and shape of lamina cribrosa (LC) pores in glaucomatous eyes over a period of time. METHODS: Baseline and follow up optic disc photographs were retrospectively studied in 39 eyes of 39 patients with glaucoma. Only eyes with a vertical cup to disc ratio equal to or greater than 0.6 were included in the study. In addition, all selected eyes had to have serial optic disc photographs obtained at least 3 years apart allowing clear visualisation of LC surface. The association of the alterations in LC surface morphology with patient specific and eye specific characteristics was statistically analysed. RESULTS: During a mean study period of 3.90 (SD 0.7) years, individual pore size (mean pore area to disc area ratio) exhibited a significant decrease between baseline and follow up measurements of each eye (p<0.0001). However, during the study period, total pore area to disc area ratio did not change (p>0.05), and the change in pore shape in some eyes (from circular to more oval and elongated) was statistically insignificant (p = 0.12). Although a relation was detectable between the optic disc and lamina cribrosa parameters at a given time, which reflects cumulative effects, during the study period, there was no significant association between the changes of the LC parameters and neural tissue damage. The rate and the magnitude of the changes in individual pore size during the study period were not significantly different among the eyes exhibiting progressive neural rim damage and those staying stable (p>0.05). CONCLUSION: These findings demonstrate that the LC surface morphology exhibits changes along with the glaucomatous optic disc damage. However, the clinical appearance of LC surface in glaucomatous eyes may continue to change, even when the neural rim damage is clinically stable. These findings are probably associated with the chronic cellular events of tissue remodelling that occur in the glaucomatous optic nerve head.

Intestinal obstruction from midgut volvulus after laparoscopic appendectomy.

We present the case of a 30-year-old man who developed a small bowel obstruction from an acute midgut volvulus 8 days after undergoing a laparoscopic appendectomy. There was no evidence of congenital malrotation or midgut volvulus on the initial computed tomography (CT) scan or at laparoscopy. Subsequently, a midgut volvulus developed in the absence of congenital malrotation.

The mucosal invasion model: a novel in vitro model for evaluating the invasive behavior of mucocutaneous malignancies.

BACKGROUND: Prevention of regional and metastatic spread of cutaneous malignancies requires understanding the physiologic mechanism of tumor cell invasion. In vitro models are convenient for studying the in vitro invasive phenotype of normal cells, tumor cell lines, or genetically altered cells in a 3-dimensional matrix, but they should attempt to recapitulate the complex in vivo submucosal environment. A new acellular extracellular matrix, porcine submucosal matrix (PSM), is thought to accurately recapitulate the submucosal matrix. A novel in vitro model using PSM to assess mucocutaneous tumor cell invasion was studied. METHODS: The morphologic characteristics, growth, and invasive behavior of human head and neck squamous cell carcinoma (UM-SCC-1, UM-SCC-5, UM-SCC-17B, and OSC-19) cell lines were assessed on the PSM gel and compared with commonly used in vitro invasion models (type I collagen and Matrigel matrices). The invasive phenotype of canine kidney cells was also assessed on each matrix, because this cell line is known to demonstrate a characteristic in vitro invasive phenotype. RESULTS: The PSM-supported head and neck squamous cell carcinoma tumor cell line growth and single cell invasion were seen under stimulated conditions, similar to type I collagen gels. The invasive phenotype of canine kidney cells behaved similarly on PSM and collagen. Matrigel did not support growth well, and invasion occurred only superficially in isolated areas. CONCLUSION: The PSM is a good in vitro model for assessment of pharmacologic and genetic manipulations of head and neck squamous cell carcinoma tumor cell lines and has several advantages over other commonly used matrices.

Postoperative antibiotic use of septoplasty: a survey of practice habits of the membership of the American Rhinologic Society.

Prophylactic antibiotics are used routinely in otolaryngology. Little objective data exist concerning their use in sinonasal procedures. We wished to determine the practice patterns of otolaryngologists regarding prophylactic antibiotics for septoplasty patients. A survey of 743 (60.3% responded) members of the American Rhinologic Society was used to get information about their practice habits and rationale for using antibiotics after septoplasty. Sixty-six percent of respondents routinely used antibiotics. Postoperative infection and toxic shock syndrome (TSS) were the primary indications. Forty-four percent of respondents used some form of packing and 38% used a splint. There was no relationship between the annual number of procedures and the reasons for using antibiotics. Doctors who performed more than 50 cases a year were less likely to use packing or splints (p < 0.001). Older surgeons used less younger surgeons a packing/splints (p < 0.001). Respondents who used packing/ splints were more likely to use antibiotics (p = 0.008). Older respondents used packing whereas younger respondents used splints (p = 0.002). The rationale for antibiotics varied by age; re more concerned with TSS and older physicians were more concerned with infection (p = 0.005). This survey shows great variability in the usage and rationale for antibiotics after septoplasty.

Emerging perceptions of facial plastic surgery among medical students.

OBJECTIVE: The purpose of this study was to examine the perceptions of medical students regarding facial aesthetic surgery and those specialists most likely to perform aesthetic or reconstructive facial surgery. METHODS: A survey was designed based on a review of the literature to assess the desirable characteristics and the perceived role of the facial plastic and reconstructive surgeon (FPRS). The surveys were distributed to 2 populations: medical students from 4 medical schools and members of the general public. RESULTS: A total of 339 surveys were collected, 217 from medical students and 122 from the general public. Medical students and the public had similar responses. The results demonstrated that respondents preferred a male plastic surgeon from the ages of 41 to 50 years old and would look to their family doctor for a recommendation. Facial aesthetic and reconstructive surgery was considered the domain of maxillofacial and general plastic surgeons, not the FPRS. CONCLUSION: Integration of the FPRS into the medical school curriculum may help to improve the perceived role of the specialty within the medical community. It is important for the specialty to communicate to aspiring physicians the dedicated training of an otolaryngologist specializing in FPRS.

Fluid transport by human nonpigmented ciliary epithelial layers in culture: a homeostatic role for aquaporin-1.

We report for the first time that cultured nonpigmented human ciliary epithelial (NPE) cell layers transport fluid. Cells were grown to confluence on permeable membrane inserts, and fluid transport across the resulting cell layers was determined by volume clamp at 37 degrees C. These cell layers translocated fluid from the apical to the basal side at a steady rate of 3.6 microl x h(-1) x cm(-2) (n = 4) for 8 h. This fluid movement was independent of hydrostatic pressure and was completely inhibited by 1 mM ouabain, suggesting it arose from fluid transport. Mercuric chloride, a nonspecific but potent blocker of Hg(2+)-sensitive aquaporins, and aquaporin-1 antisense oligonucleotides both partially inhibited fluid transport across the cell layers, which suggests that water channels have a role in NPE cell homeostasis. In addition, these results suggest that of the two ciliary epithelial layers in tandem, the NPE layer by itself can transport fluid. This cultured layer, therefore, constitutes an interesting model that may be useful for physiological and pharmacological characterization of ciliary epithelial fluid secretion.

Use of the radial forearm free tissue flap to treat persistent stricture after esophagogastrectomy.

BACKGROUND: Persistent stricturing or anastomotic leakage at the cervical esophagogastric anastomosis can be a troublesome complication of gastric pull-up procedures. When the stricture is the result of ischemia of the stomach, the strictures are long and often not responsive to dilatation and require large operations such as jejunal interposition or replacement with colonic pull-up. In this report we describe the use of a radial forearm flap to patch strictures. METHODS: The radial forearm flap is a fascia cutaneous flap taken from the forearm and based on the radial artery and its venae comitantes. The advantages of this flap are that it is thin and pliable, conforms easily, has excellent reliability due to the size of the feeding vessels, and has a relatively long pedicle. The vascular anastomosis can be made to several arteries and veins within the neck. The epithelial component can be made in sizes up to 10 by 20 cm. RESULTS: We have used the radial forearm flap to patch strictures in 6 patients with persistent complex strictures in the cervical region after esophagectomy. Results were excellent in 4 patients (able to eat liquids and solids without problems) and good in 1 patient (liquids okay, some problem with solids), and 1 patient died postoperatively. Follow-up is 4 months to 7 years. CONCLUSIONS: The radial forearm flap is an excellent option for handling persistent stricture after esophagogastrectomy. In many instances, this flap can be used in lieu of a jejunal interposition flap and obviates a laparotomy to harvest jejunum. The flap fits easily into the neck and conforms to the space.

Tracheoesophageal puncture in the office setting with local anesthesia.

Tracheoesophageal puncture (TEP) with voice prosthesis placement is currently the method of choice for vocal rehabilitation of patients who have undergone total laryngectomy. Occasionally, secondary TEP needs to be performed. We have used a TEP technique that is performed in the clinic setting with local anesthesia and no sedation. The purpose of this study was to review our technique and experience and to evaluate results, complications, and patients' acceptance of the procedure. We performed a retrospective chart review of the records of 14 patients who had undergone total laryngectomy and secondary TEP placement in the clinic setting. The procedure was well tolerated. The voice results were fair to good in 11 of 12 patients. There was 1 complication, a false passage between the trachea and the esophagus. Voicing was immediate in 12 of the 14 cases. We conclude that TEP can be performed in the office setting with local anesthesia. The voice results are excellent, and the procedure is well tolerated by the patient. Proper patient selection and regular follow-up by a speech-language pathologist are important.

TNF-alpha and TNF-alpha receptor-1 in the retina of normal and glaucomatous eyes.

PURPOSE: To determine the expression and localization of tumor necrosis factor (TNF)-alpha and TNF-alpha receptor-1 in the retina of normal and glaucomatous eyes. METHODS: Using immunohistochemistry and in situ hybridization, retinal expression and localization of TNF-alpha and TNF-alpha receptor-1 were studied in retina sections from 20 eyes of donors with glaucoma, and 20 eyes of age-matched normal donors. RESULTS: According to immunohistochemistry, the intensity of the immunostaining and the number of labeled cells for TNF-alpha or its receptor were greater in retina sections of glaucomatous eyes than in control eyes of age-matched normal donors. In situ hybridization showed that mRNA signals for TNF-alpha or TNF-alpha receptor-1 were similarly more intense in glaucomatous eyes than in age-matched control eyes. Both protein and mRNA of TNF-alpha or TNF-alpha receptor-1 were predominantly localized to the inner retinal layers. Double-immunofluorescence labeling demonstrated that retinal immunostaining for TNF-alpha was predominantly positive in the glial cells, whereas immunostaining for TNF-alpha receptor-1 was mainly positive in the retinal ganglion cells. CONCLUSIONS: Upregulation of TNF-alpha and its receptor-1 in glaucomatous retina suggest that TNF-alpha-mediated cell death is involved in the neurodegeneration process of glaucoma.

Clinical factors associated with progression of glaucomatous optic disc damage in treated patients.

BACKGROUND: Reducing intraocular pressure (IOP) in glaucomatous eyes does not always prevent disease progression. OBJECTIVE: To determine the clinical factors associated with progressive optic disc damage in glaucomatous eyes receiving treatment to reduce IOP. METHODS: Baseline and follow-up optic disc photographs as well as demographic and clinical data were retrospectively studied in 186 eyes of 93 patients with primary open-angle glaucoma, and in 138 eyes of 69 patients with normal-pressure glaucoma. The patients with primary open-angle glaucoma were included in the study only if their treated IOPs during a follow-up period of 5 years were less than 21 mm Hg. The patients with normal-pressure glaucoma were included only if their IOPs were reduced by at least 20% during the follow-up period. The association of progressive optic disc damage with patient- and eye-specific characteristics was examined using multivariate analysis. RESULTS: During the 5-year study period, 141 (43.5%) of the 324 eyes exhibited progressive optic disc damage defined by at least a 5% decrease in the neural rim area-to-disc area ratio. Using multivariate analysis, the following were found to be strongly associated with progressive neural rim damage: a baseline smaller neural rim area-disc area ratio (P<.001); a baseline larger zone beta area-disc area ratio (P =.04); a baseline larger parapapillary atrophy length-disc circumference ratio (P =.05); a diagnosis of normal-pressure glaucoma (P =.01); and combined medical and surgical treatment prior to the study period (P =.01). CONCLUSIONS: Clinical factors other than IOP may be important indicators of subsequent progression of glaucomatous optic disc damage. Our findings suggest that eyes with advanced glaucomatous optic disc damage and normal-pressure glaucoma are more likely to progress despite receiving treatment to reduce IOP.

Serum autoantibody against glutathione S-transferase in patients with glaucoma.

PURPOSE: To identify retinal proteins that are the targets of serum autoantibodies in patients with glaucoma. METHODS: To identify retinal antigens that are recognized by the sera of patients with glaucoma, immunoreactive bands were separated, by using two-dimensional gel electrophoresis of the bovine retinal soluble fraction. A 29-kDa band was then selected for further analysis. Tryptic peptides of the 29-kDa band were analyzed using electrospray mass spectrometry to identify the protein. After protein identification, immunoreactivity against this newly identified protein was studied by Western blot analysis using sera from 65 patients with glaucoma (25 with primary open-angle glaucoma [POAG]; 40 with normal-pressure glaucoma [NPG]) and 25 age-matched healthy subjects. In addition, serum antibody titers were compared in these groups, by using a specific enzyme-linked immunosorbent assay (ELISA). RESULTS: The 29-kDa band was identified as glutathione S-transferase (GST). Western blot analysis revealed that serum antibodies against GST antigen were recognized in 34 (52%) of 65 patients with glaucoma (22 of NPG and 12 of POAG) and 5 (20%) of 25 age-matched control subjects (chi(2) test, P < 0.05). By ELISA, it was also found that patients with glaucoma had higher titers of anti-GST antibody, compared with the control group (Mann-Whitney test; NPG versus control, P = 0.013; POAG versus control, P = 0.0006). CONCLUSIONS: These findings indicate that GST is one of the retinal antigens targeted by the serum antibodies detected in some patients with glaucoma.

A prospective comparison of scalpel versus bipolar scissors in the elevation of radial forearm fasciocutaneous free flaps.

OBJECTIVES/HYPOTHESIS: The radial forearm fasciocutaneous free flap has become the workhorse for reconstruction of head and neck ablative defects. A location distal to the head and neck allows this flap to be elevated concurrent with the ablation. Most commonly, the flap is elevated under tourniquet control. This involves a primary ischemic insult with a certain amount of hemorrhage after the tourniquet is released. Bipolar scissors are a new method of dissection. They may allow for a speedier dissection with a concomitant decrease in ischemic time. Their hemostatic properties may control hemorrhage after use of the tourniquet. STUDY DESIGN: A prospective study of patients undergoing radial forearm free flaps over a 12-month period at a tertiary care referral center was undertaken. RESULTS: Forty patients were entered into the study, flaps were elevated with scalpel (20) and with bipolar scissors (20). Mean time under tourniquet was 39 minutes (range, 30-56 min) with scalpel compared with 27 minutes (range, 21-31 min) with bipolar scissors (P <.001). Total mean time of elevation (including control of hemostasis and pedicle dissection) for scalpel elevation was 50 minutes (range, 35-61 min) compared with 32 minutes (range, 20-41 min) for bipolar scissors elevation (P <.001). Mean blood loss was 46 mL (range, 15-110 mL) in the scalpel elevation group compared with 14 mL (range, 0-50 mL) in the bipolar scissors elevation group (P <.001). Complications at the donor site were equal between groups. CONCLUSIONS: Bipolar scissors are a safe, efficient method for elevating radial forearm free flaps.

Effect of anemia on the fasciocutaneous flap survival in a rat model.

OBJECTIVE/HYPOTHESIS: Ablative surgery for head and neck cancer that creates large composite defects often results in a significant decrease in the hematocrit level. These defects are best reconstructed with a microvascular free tissue transfer. Effect of the decreased hematocrit on microvascular flap survival is controversial. The purpose of this study was to assess the effect of isovolemic anemia on flap survival in a rat model. STUDY DESIGN: Prospective analysis. METHODS: Ninety rats were used (30 control and 60 experimental animals). Experimental animals were rendered anemic by blood draw and volume resuscitated with either a colloid (30 animals) or crystalloid (30 animals) solution. In all animals a ventral fasciocutaneous flap was raised. A vascular clamp was applied to the arteriovenous pedicle, and different ischemic times were allowed to elapse before clamp removal. Flap survival was assessed at 5 days. Probit analysis was performed for the three animal groups. RESULTS: A significantly increased probability of the flap survival was found in the anemic animals compared with the control group (P < or = .05). No difference was found between the colloid and crystalloid resuscitation groups. CONCLUSIONS: A decreased hematocrit level increases fasciocutaneous flap tolerance to ischemia and significantly increases the primary ischemic time in the ventral flap clamp model in rats. Fluid replacement with either crystalloid or colloid produces identical results.

In vitro evaluation of reactive astrocyte migration, a component of tissue remodeling in glaucomatous optic nerve head.

In order to improve understanding of remodeling events in the glaucomatous optic nerve head, the migration of optic nerve head astrocytes was studied in vitro. Since elevated intraocular pressure is an important stress factor identified in glaucomatous eyes, optic nerve head astrocytes were incubated under physical stress created by elevated hydrostatic pressure. In addition, they were incubated in the presence of a chemical stimulus, lipolysaccharide (LPS). Migration of reactivated astrocytes in the presence of these stressors was examined using chambers in which cell migration through extracellular matrix-coated pores is only possible following proteolytic digestion of the matrix. We observed that the migratory ability of optic nerve head astrocytes was approximately 4-6 times greater following exposure to elevated hydrostatic pressure or LPS for up to 48 h. Phosphoinositide 3-kinase, protein kinase C, and tyrosine kinase were found to be involved in the signal transduction for activated migration of optic nerve head astrocytes in response to elevated hydrostatic pressure or LPS. In addition, we observed that the stress-induced migration of optic nerve head astrocytes, which is accompanied by proteolytic degradation, resulted in the formation of culture cavities containing mucopolysaccharides. These in vitro findings provide a clearer understanding of the pathophysiologic mechanisms of characteristic tissue remodeling events that occur, in vivo, in the glaucomatous optic nerve head.