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Biomedical subjects

S E Wilson

Publications and source records attributed to S E Wilson.

At least 19 recordsLinked to original sources
PubMed1992

Guidelines for surgical residents' working hours. Intent vs reality.

To comply with voluntary California medical school guidelines, our general surgery residency program reduced in-house call to 1 in 4 nights, and scheduled a 72-hour work-week. We assessed the effectiveness of these changes by prospectively surveying the actual working hours of surgical house staff through completion of a daily schedule for 1 month. Actual in-hospital hours averaged 98 per week, significantly exceeding the scheduled hours, and were greater for interns (100 hours) and junior residents (97 hours) than for chief residents (95 hours). Twenty hours (22%) of nonconference waking hours were spent on so-called scut work. Significant reduction of intern work hours could be accomplished by expansion of ancillary care, allowing more time for direct patient care. The effect on senior house staff hours would be less dramatic but might be sufficient to bring hours into compliance with proposed limits.

General Surgery↗
PubMed1992

Unexpected, late cardiovascular effects of surgery for peripheral artery disease. Veterans Affairs Cooperative Study 199.

In reviewing late morbidity of a multicenter clinical trial comparing balloon angioplasty (percutaneous transluminal angioplasty) with bypass surgery for lower-extremity ischemia, an unexpectedly high incidence of adverse systemic events in surgical patients was uncovered. The study was prospective and randomized, and included a total of 263 patients, with follow-up from 2 to 6 years. When end points of related deaths, amputations, and intervention failures were summed, surgery was favored over percutaneous transluminal angioplasty at 4 years. Progression of cardiac and renal dysfunction and mortality differed between groups. A total of 42 deaths were in the group who underwent surgery and 27 in those who underwent percutaneous transluminal angioplasty. The percentage difference in death rate between the two groups increased each year to reach 10% at 5 years. A significant difference in renal function was noted in nine patients who underwent surgery and zero who underwent percutaneous transluminal angioplasty. Myocardial infarctions were greater on follow-up of surgical patients. After 6 years, congestive heart failure had occurred in 19 patients who underwent surgery and eight who underwent percutaneous transluminal angioplasty. The trends in this study of patients with only moderately severe peripheral arterial disease suggest an increased rate of deterioration of cardiac and renal function in patients who have arterial operations. In surgical patients, mortality was 13.1% per year, whereas it was 8.4% for patients treated with percutaneous transluminal angioplasty. Future intervention studies should include long-term follow-up of such cardiovascular events.

Amputation, Surgical↗
PubMed1992

The effect of fibrin glue on intraperitoneal contamination in rats treated with systemic antibiotics.

Intraperitoneal fibrin sealant lowers septic mortality in a rat model of peritoneal contamination (2 x 10(6) organism inoculum) at the cost of increased late intraabdominal abscesses. This study utilized parenteral antimicrobials to determine if the protective effect of intraperitoneal fibrin could be achieved without increasing the late abscess formation rate. One hundred and fifty-five rats were divided into four groups. Gelatin capsules containing various dilutions of feces (10(10) CFU/ml) and barium sulfate were placed into the abdomen in all groups. Group I controls had no antibiotics or fibrin. In group II, the capsule was surrounded by a solution of cryoprecipitate, thrombin, and calcium (fibrin "glue"). Groups III (no fibrin, antibiotics) and IV (fibrin, antibiotics) received a broad-spectrum cephalosporin intramuscularly postoperatively and then daily. Surviving rats were sacrificed on the tenth postoperative day. At a moderate volume of fecal inoculum (0.3 ml), fibrin reduced mortality from 100% in the control group to 0% in treated animals (P less than 0.001) that did not receive antibiotics. Abscesses formed in 10% of the surviving fibrin-treated rats which were implanted with 0.1 ml of inoculum. In the 0.2 and 0.3 ml inoculum groups substantially more abscesses occurred (75 and 70%, respectively). The protective effect of fibrin was not manifested in the antibiotic-treated rats since no deaths occurred in either group. At higher and lower inoculum doses, no significant differences between fibrin and control groups were observed in mortality or abscess formation, whether or not antibiotics were given.(ABSTRACT TRUNCATED AT 250 WORDS)

Abscess↗
PubMed1992

New estimates of the direct costs of traumatic spinal cord injuries: results of a nationwide survey.

New estimates of the direct costs of traumatic spinal cord injuries (SCI) are obtained from a comprehensive survey of the US SCI population. These direct costs, defined as the value (in 1988 dollars) of resources used specifically to treat or to adapt to the SCI condition, represent the average experience of the US SCI population. Responses to a detailed questionnaire administered to a sample of traumatic SCI persons in the United States provide the primary source of data for this study. Analysis of this survey data indicates that more recently injured SCI persons (ie those injured since 1970) spent an average of 171 days in a hospital over the first 2 years post injury. Initial hospital expenses will average $95,203. Home modification costs in excess of $8,000 can also be expected. After recovery and rehabilitation, a SCI person will pay, on average, $2,958 per year in hospital expenses and $4,908 per year for other medical services, supplies and adaptive equipment. Personal assistance costs and costs of institutional care will average $6,269 per year. These cost estimates represent the incremental costs of SCI, ie they exclude any costs that would have been incurred in the absence of SCI.

Adolescent↗
PubMed1992

Modified polytetrafluoroethylene: indium 111-labeled platelet deposition on carbon-lined and high-porosity polytetrafluoroethylene grafts.

Platelet accumulation on carbon-lined (CL) and high-porosity (HP) polytetrafluoroethylene (PTFE) grafts was investigated in vivo. In experiment 1, 20 CL grafts and 20 control PTFE grafts, each 5 cm in length and 4 mm in diameter, were interposed into both carotid and femoral arteries of 10 dogs. In experiment 2, 12 HP grafts (90 microns mean internodal distance) and 12 control PTFE grafts were implanted in six dogs. Indium 111-labeled platelets were injected intravenously and the grafts were retrieved 48 hours later. Radioactivity of the grafts and a control segment of the carotid artery was counted. A graft platelet accumulation index (GPAI) was calculated as the ratio of emission from the graft compared to that from the control segment. The GPAI of the CL graft was significantly less than the GPAI of the control graft in both the carotid (control 29.7 +/- 5.46, CL 22.3 +/- 6.55; n = 9 [p < 0.05]) and the femoral arteries (control 30.7 +/- 9.65, CL 22.0 +/- 6.59; n = 9 [p < 0.05]). There was no significant difference in GPAI between the control and HP grafts in the carotid arteries (control 30.6 +/- 11.8, HP 31.5 +/- 9.71; n = 6) and in the femoral arteries (control 31.5 +/- 7.88, HP 34.0 +/- 4.97; n = 6). Carbon lining decreases platelet accumulation on PTFE grafts in the early postoperative period, and HP grafts do not exhibit increased platelet uptake.

Animals↗
PubMed1992

Accuracy and precision of the corneal analysis system and the topographic modeling system.

Two computer-assisted topographic analysis systems were evaluated with calibrated spherical surfaces and normal human corneas. The Topographic Modeling System-1 (TMS-1) was found to be statistically more accurate in determining the power of calibrated spheres near the apex and at 1 mm from the apex than the Corneal Analysis System (CAS). The CAS, however, was statistically more accurate at 3 mm from the apex with each calibrated sphere. The small differences in accuracy between the two instruments, however, are unlikely to be of clinical significance. The topographic patterns on color-coded maps from 22 normal corneas of 11 subjects were similar with the two instruments. Simulated keratometry values with the CAS more accurately identified the keratometer-determined major cylinder axis compared with the TMS-1. Conversely, the TMS-1 was more accurate than the CAS at determining the level of corneal astigmatism.

Astigmatism↗
PubMed1992

Two-dimensional gel electrophoretic comparison of endothelial cell-Descemet's membrane proteins in Fuchs' dystrophy and normal corneas.

Two-dimensional polyacrylamide gel electrophoresis was used to compare the proteins isolated from the combined corneal endothelial cell-Descemet's membrane complex of three pairs of corneas with Fuchs' dystrophy with three pairs of normal corneas. Normal or Fuchs' dystrophy endothelium and Descemet's membrane was documented by pathologic analysis of each cornea. Proteins were separated by isoelectric point in the first dimension and molecular weight in the second dimension. Over 300 proteins were resolved from each sample, and similar patterns were noted in both groups. No consistent differences were detected between the corneas with Fuchs' dystrophy and the normal corneas. Allelic variations of some proteins were detected in both groups.

Cornea↗
PubMed1992

Subcapsular hematoma as a predictor of delayed splenic rupture.

Over the past 46 months at a level I trauma center, 966 computed tomography (CT) scans were performed for blunt abdominal trauma. Eighty-three (8.6%) demonstrated splenic injury, and 31 (3.2%) of these showed a subcapsular hematoma with or without associated parenchymal damage. Of the 31 patients, 23 were managed conservatively, based initially upon surgeons' preference (14 patients) and after March 1990 to conform to the authors' splenic trauma protocol (nine patients). The eight patients operated upon were hemodynamically stable and all underwent splenectomy. Subcapsular hematoma, as diagnosed by preoperative CT scan, was confirmed in each of the eight celiotomies. Parenchymal involvement, which had also been identified in these eight patients by CT, was evident at operation in all, and hilar involvement occurred in three. None of the 23 observed patients developed delayed splenic rupture. All were discharged home with outpatient follow-up in surgical clinic to at least 1 month without further complication. The authors came to the following conclusions: 1) Subcapsular hematoma is neither a predictor for delayed splenic rupture, nor by itself an indication for operative management of the injured spleen in the hemodynamically stable patient; 2) Degree of parenchymal injury based on CT morphology, specifically hilar involvement, signifies the need for laparotomy with splenectomy; 3) Splenorrhaphy has a reduced role in splenic trauma because most injuries now operated upon are severe.

Blood Transfusion↗
PubMed1992

Contact lens manipulation of corneal topography after penetrating keratoplasty: a preliminary study.

We conducted a preliminary retrospective study of five eyes that had undergone penetrating keratoplasty (PK) to determine if rigid gas permeable (RGP) contact lenses could be used as splints or molds to improve postoperative corneal topography. RGP lenses were fit 3-6 months (mean: 4.1 months) after PK and 3-4 months (mean: 1.8 months) after removal of the 10-0 nylon suture. Lenses were fit to attain a contact lens resting position centered on the corneal graft. After 4 to 8 months (mean: 6.2 months) of contact lens wear, analysis of corneal topography showed a decrease in simulated keratometry cylinder from 4.7 +/- 0.6 D (mean +/- 1 standard deviation) to 1.8 +/- 0.8 D (P = 0.02) and an improvement in anterior corneal surface regularity (surface regularity index: initial = 1.40 +/- 0.2; final = 1.0 +/- 0.2; P = 0.04). Three eyes were fit with a well-centered RGP lens; two eyes were fit with lenses that rode off-center. Increased irregular astigmatism in the two eyes with decentered contact lenses suggests the importance of centering RGP lenses with respect to corneal grafts. The best corrected spectacle visual acuity either improved or remained unchanged in four of five eyes after contact lens wear. One eye demonstrated a decrease in best corrected spectacle acuity by one Snellen line after 3 months of lens wear. Further clinical studies are needed to determine the potential of postoperative use of RGP lenses to improve corneal surface regularity, to decrease astigmatism, and to optimize visual results.

Astigmatism↗
PubMed1992

Laser-assisted balloon angioplasty.

At present, the precise applications and indications for laser angioplasty are poorly defined. The method offers a new and effective technique for transluminal recanalization of occluded arterial segments. By creating a lumen to allow the passage of a guidewire across a segment of occluded vessel without creating a dissection, laser angioplasty provides a valuable adjunct to the technology of percutaneous transluminal angioplasty. Laser techniques are being investigated extensively in surgical patients and, although the long-term patency rates are disappointing at present, the technique shows promise as an alternative to bypass operations in poor-risk patients or those with unfavorable surgical anatomy. Improved results of this minimally invasive technique in recanalizing stenoses and short lesions may ultimately redefine the criteria for intervention in this group of patients. We are optimistic that the technique will be developed to offer the vascular surgeon a new modality for treating a larger segment of the patient population suffering from occlusive peripheral vascular disease.

Angioplasty, Laser↗
PubMed1992

EGF, EGF receptor, basic FGF, TGF beta-1, and IL-1 alpha mRNA in human corneal epithelial cells and stromal fibroblasts.

We sought to determine whether human corneal epithelial cells and stromal fibroblasts synthesize messenger RNAs (mRNA) coding for epidermal growth factor (EGF), EGF receptor, basic fibroblast growth factor (basic FGF), transforming growth factor-beta 1 (TGF-beta 1), and interleukin-1 alpha (IL-1 alpha). Total cellular RNA was extracted from cultured stromal fibroblasts and ex vivo and cultured corneal epithelial cells. Oligo dt-primed complementary DNA (cDNA) was synthesized from each RNA sample. The polymerase chain reaction (PCR) was used to amplify sequences for EGF, EGF receptor, basic FGF, TGF-beta 1, IL-1 alpha, and beta actin from cDNA samples from each cell type. Southern blots of the PCR products were probed with oligonucleotides complementary to internal sequences within each of the amplified products. The amplification products were shown to be specific. For each modulator, the amplification product of the expected size was identified with at least one specific, alternative amplification product. The alternative splicing products suggest that there may be alternative mRNA splicing for each of the modulators studied. Differences were noted in the IL-1 alpha specific amplification products in stromal fibroblasts compared to corneal epithelial cells. EGF and EGF receptor mRNA production in human corneal epithelial cells and stromal fibroblasts suggest an autocrine role for EGF in the physiology of each of these cell types.

Adolescent↗
PubMed1992

Single dose cephalosporin prophylaxis in high-risk patients undergoing surgical treatment of the biliary tract.

During June 1985 through October 1986, 292 patients considered to be at high risk for having postoperative complications develop underwent cholecystectomy and were evaluated in a multicenter, randomized, prospective, double-blind study. Risk factors included age greater than 70 years, acute cholecystitis within the previous six months, obstructive jaundice, obesity and diabetes mellitus. One gram of cefamandole was administered intravenously to 144 patients and 148 patients received 1 gram of cefotaxime intravenously 30 minutes prior to skin incision. Culture-proved bactibilia was found in 55 patients and 11 of the patients had choledocholithiasis. Of the risk factors considered to place patients at high risk for postoperative infectious complications, obesity and acute cholecystitis proved to be the more common. However, age greater than 70 years, diabetes mellitus and obstructive jaundice were more significant risk factors predisposing to bactibilia. The most common organisms isolated from the bile and gallbladder intraoperatively were Staphylococcus, Streptococcus and Klebsiella species along with enterococcus, Escherichia coli and diphtheroids. Clinically significant postoperative infections occurred in eight patients, including six patients in the cefamandole group and two patients in the cefotaxime group. Antibiotic concentrations were measured in the serum, muscle, subcutaneous fat, gallbladder and bile, with cefamandole showing statistically significant greater concentrations in bile, gallbladder and muscle tissue. There was no statistical significance between the postoperative infection rates, total period of hospitalization or total hospital charges for each group. Therefore, there is no significant advantage between a single prophylactic dose of cefamandole versus cefotaxime for high-risk patients undergoing biliary tract operation.

Adolescent↗
PubMed1992

EGF, basic FGF, and TGF beta-1 messenger RNA production in rabbit corneal epithelial cells.

The polymerase chain reaction (PCR) was used to demonstrate that rabbit corneal epithelial cells produce messenger RNAs coding for epidermal growth factor (EGF), basic fibroblast growth factor (FGFb), and transforming growth factor beta-1 (TGF beta 1) ex vivo and in primary culture. EGF, FGFb, and TGF beta 1 mRNAs were detected in central and peripheral ex vivo epithelial tissue in wounded and unwounded rabbit corneas. Southern blots of the PCR products were probed with oligonucleotides to demonstrate that the appropriately sized amplification products were specific. These results suggest that corneal epithelial cells produce growth factors that may have autocrine or paracrine effects on epithelial cells, and possibly other cells of the cornea. The functions, if any, performed by these growth factors in corneal epithelial wound healing are yet to be elucidated.

Animals↗
PubMed1991

The yeast GLC7 gene required for glycogen accumulation encodes a type 1 protein phosphatase.

The glc7 mutant of the yeast Saccharomyces cerevisiae does not accumulate glycogen due to a defect in glycogen synthase activation (Peng, Z., Trumbly, R. J., and Reimann, E.M. (1990) J. Biol. Chem. 265, 13871-13877) whereas wild-type strains accumulate glycogen as the cell cultures approach stationary phase. We isolated the GLC7 gene by complementation of the defect in glycogen accumulation and found that the GLC7 gene is the same as the DIS2S1 gene (Ohkura, H., Kinoshita, N., Miyatani, S., Toda, T., and Yanagida, M. (1989) Cell 57, 997-1007). The protein product predicted by the GLC7 DNA sequence has a sequence that is 81% identical with rabbit protein phosphatase 1 catalytic subunit. Protein phosphatase 1 activity was greatly diminished in extracts from glc7 mutant cells. Two forms of protein phosphatase 1 were identified after chromatography of extracts on DEAE-cellulose. Both forms were diminished in the glc7 mutant and were partly restored by transformation with a plasmid carrying the GLC7 gene. Southern blots indicate the presence of a single copy of GLC7 in S. cerevisiae, and gene disruption experiments showed that the GLC7 gene is essential for cell viability. The GLC7 mRNA was identified as a 1.4-kilobase RNA that increases 4-fold at the end of exponential growth in wild-type cells, suggesting that activation of glycogen synthase is mediated by increased expression of protein phosphatase 1 as cells reach stationary phase.

Blotting, Southern↗
PubMed1991

Identification of a glycogen synthase phosphatase from yeast Saccharomyces cerevisiae as protein phosphatase 2A.

A glycogen synthase phosphatase was purified from the yeast Saccharomyces cerevisiae. The purified yeast phosphatase displayed one major protein band which coincided with phosphatase activity on nondenaturing polyacrylamide gel electrophoresis. This phosphatase had a molecular mass of about 160,000 Da determined by gel filtration and was comprised of three subunits, termed A, B, and C. The subunit molecular weights estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were 60,000 (A), 53,000 (B), and 37,000 (C), indicating that this yeast glycogen synthase phosphatase is a heterotrimer. On ethanol treatment, the enzyme was dissociated to an active species with a molecular weight of 37,000 estimated by gel filtration. The yeast phosphatase dephosphorylated yeast glycogen synthase, rabbit muscle glycogen phosphorylase, casein, and the alpha subunit of rabbit muscle phosphorylase kinase, was not sensitive to heat-stable protein phosphatase inhibitor 2, and was inhibited 90% by 1 nM okadaic acid. Dephosphorylation of glycogen synthase, phosphorylase, and phosphorylase kinase by this yeast enzyme could be stimulated by histone H1 and polylysines. Divalent cations (Mg2+ and Ca2+) and chelators (EDTA and EGTA) had no effect on dephosphorylation of glycogen synthase or phosphorylase while Mn2+ stimulated enzyme activity by approximately 50%. The specific activity and kinetics for phosphorylase resembled those of mammalian phosphatase 2A. An antibody against a synthetic peptide corresponding to the carboxyl terminus of the catalytic subunit of rabbit skeletal muscle protein phosphatase 2A reacted with subunit C of purified yeast phosphatase on immunoblots, whereas the analogous peptide antibody against phosphatase 1 did not. These data show that this yeast glycogen synthase phosphatase has structural and catalytic similarity to protein phosphatase 2A found in mammalian tissues.

Chromatography, Affinity↗
PubMed1991

Epidermal growth factor messenger RNA production in human lacrimal gland.

Experimental models and clinical investigations have suggested that epidermal growth factor (EGF) may have a role in corneal wound healing. It has been identified as a normal component of human tears. Rabbit and mouse lacrimal glands have recently been shown to synthesize EGF messenger RNA (mRNA). The purpose of the present study was to determine whether the human lacrimal gland synthesizes EGF mRNA. Total cellular RNA was isolated from pathologic specimens of normal human lacrimal glands from two individuals. Reverse transcriptase was used to generate complementary DNA (cDNA) using a human EGF-specific mRNA primer. Amplification of EGF-related cDNA sequences was performed with the polymerase chain reaction (PCR) and human EGF-derived up- and downstream primers. The PCR products from both lacrimal glands contained an amplified product of the expected length of approximately 410 base pairs. The PCR-generated fragment was verified as an EGF-related amplification product with Southern blotting using a synthetic oligonucleotide probe derived from the mature coding sequence of EGF. These results conclusively demonstrate that the human lacrimal gland synthesizes EGF and suggest that the lacrimal gland could have a regulatory role in maintaining the ocular surface and possibly regulating corneal wound healing through the secretion of EGF.

Base Sequence↗
PubMed1991

In vivo study of an elastomer end-coated polytetrafluoroethylene vascular prosthesis.

Polyurethane end-coated polytetrafluoroethylene (PTFE) grafts (elastomer PTFE grafts) were implanted in 12 female adult mongrel dogs to assess patency, intimalization, tissue incorporation, and technical suitability of the material as a vascular graft. Each dog had bilateral aortoiliac grafts placed, one a standard PTFE and the other an elastomer PTFE graft. The length of the grafts was 7-8 cm and the diameter was 6 mm. The grafts were harvested at intervals to 120 days postoperatively. The elastomer PTFE grafts showed superior longitudinal elasticity, retention of shape, and no graft tearing with suture tension; however, no significant difference in bleeding was noted at the anastomoses between the standard and elastomer PTFE grafts. Satisfactory patency was obtained with both standard (8/10) and elastomer PTFE grafts (9/10) at 90-120 days. No significant difference in the thickness of intima and the length of pannus ingrowth was noted between the standard and elastomer PTFE grafts. No outer tissue incorporation was seen at the elastomer-treated graft segments as opposed to the well-incorporated untreated segments. In conclusion, elastomer end-coating of a PTFE vascular prosthesis provided excellent handling characteristics without detracting from patency; however, the lack of outer tissue incorporation may be a potential disadvantage in its clinical use.

Anastomosis, Surgical↗