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Biomedical subjects

S Sherman

Publications and source records attributed to S Sherman.

At least 145 records · Page 8Linked to original sources
PubMed1994

Familial split hand/split foot long bone deficiency does not segregate with markers linked to the SHFD1 locus in 7q21.3-q22.1.

Ectrodactyly (split hand/split foot, SHSF) is characterized by the absence of middle rays of the hand or the foot. Cytogenetic analyses of some of the cases have indicated an association between chromosomal rearrangements involving 7q21.3-q22 and ectrodactyly. Based on these observations, an autosomal dominant form of ectrodactyly is assumed to reside in this region and the locus has been designated SHFD1 (split hand/split foot disorder). Here we report a large family where split hand/split foot long bone deficiency (SHFLD) segregates in an autosomal dominant mode. Linkage analysis, using microsatellite markers located in 7q21-q22, excludes this region from containing the gene responsible for SHFLD in this family. These results would appear to indicate genetic heterogeneity exists in autosomal dominant SHSF.

Abnormalities, Multiple↗
PubMed1994

Intravenous cholangiography with helical CT: comparison with endoscopic retrograde cholangiography.

PURPOSE: To determine whether helical computed tomography (CT) performed during intravenous cholangiography can provide useful images of the biliary tree and to compare this technique with endoscopic retrograde cholangiography (ERC). MATERIALS AND METHODS: Eighteen adult patients with clinically suspected biliary disease who were referred for ERC were first examined with helical CT cholangiography performed 75 minutes after intravenous infusion of 100 mL of 10.3% iodipamide meglumine. RESULTS: Helical CT cholangiography revealed good opacification of the biliary tree in 13 of 14 patients with serum bilirubin levels less than 2 mg/dL (34 mumol/L) and poor opacification in three of four patients with levels greater than 2 mg/dL. In six of seven patients with choledocholithiasis, the diagnosis was made by means of helical CT cholangiography. CONCLUSION: Helical CT cholangiography may be a clinically useful method for visualization of the biliary tree in some patients with suspected biliary disease with normal bilirubin levels and in patients in whom attempts at ERC fail.

Adult↗
PubMed1994

Clostridium perfringens type A enterotoxin induces tissue damage and fluid accumulation in rabbit ileum.

Rabbit ileal loops were treated with purified Clostridium perfringens enterotoxin (CPE) to compare the onset of toxin-induced tissue damage with the onset of fluid transport changes (i.e. diarrhoea). Mild changes in fluid transport were detectable after 15 minutes of toxin treatment and then increased progressively with time. Histopathologic studies on toxin-treated ileal loops and measurement of toxin-treated loop fluid protein contents (an indirect marker for tissue damage) both indicated that detectable CPE-induced tissue damage also occurred within 15 minutes of toxin treatment and then progressively increased for at least the first 30 minutes of CPE treatment. Luminal fluid from CPE-treated loops contained elevated Ca2+ levels compared to control luminal fluid, but these elevated Ca2+ levels were not required to initiate in vivo CPE pathophysiologic effects. Since the onsets and severity of tissue damage and fluid transport changes coincided for at least the first 30 minutes of CPE treatment in our study, these results are consistent with CPE-induced tissue damage having a role in the initiation and extent of diarrhoea occurring during C. perfringens type A food poisoning.

Animals↗
PubMed1994

Wire-guided sphincterotomy.

Guidewire-assisted techniques have acquired an important role in endoscopic interventions in the pancreaticobiliary tree. The wire-guided sphincterotome allows the endoscopist to maintain direct access to the biliary tree before or after the sphincterotomy. It has the additional advantages of allowing for more expeditious placement of accessories and being useful in combined percutaneous-endoscopic procedures. There are two basic designs of wire-guided sphincterotomes. The single-channel model has a single lumen for both the cutting wire and guidewire and requires guidewire removal before the application of power. The double-channel model has two separate lumens for the guidewire and stainless steel cutting wire. In vitro data suggest that significant capacitive coupling currents (or short circuits) may occur on the standard Teflon-coated guidewire when used with a double lumen sphincterotome, resulting in electrosurgical burns. Thus, the manufacturers of the double-lumen models recommend removing the Teflon-coated wire before performing sphincterotomy. Although limited data in humans have been published, it appears that wire-guided sphincterotomy and standard sphincterotomy have similar complication rates. More safety information in humans is awaited.

Humans↗
PubMed1994

Endoscopic measurement of pancreatic blood flow.

Based on the notion that reductions in pancreatic blood flow may play a role in the pathophysiology of chronic pancreatitis, a method for measuring pancreatic blood flow, using H2 gas clearance with a ductal electrode, was developed. Preliminary animal experiments using this methodology suggest that the fibrotic pancreas behaves like a closed compartment. The scarring results in ductal and interstitial hypertension, which decreases pancreatic blood flow. This reduction in blood flow may be important in both the pathogenesis of the disease as well as the etiology of the pain. Preliminary human studies, measuring pancreatic blood flow with an H2 electrode placed endoscopically, support these findings. Further studies will be necessary to confirm this novel hypothesis.

Animals↗
PubMed1993

Concordance and recessive inheritance of Leber congenital amaurosis.

Pedigrees were obtained on 43 patients with confirmed Leber congenital amaurosis, a rare form of blindness caused by congenital dysfunction of the retina. All of the pedigrees were consistent with autosomal recessive inheritance and the segregation frequency using classical segregation analysis was 0.24 +/- 0.07. Six of the 7 affected sib pairs were concordant in regards to systemic abnormalities. Despite previous reports that Leber congenital amaurosis can be inherited either as an autosomal dominant or recessive condition, our findings support only an autosomal recessive inheritance of this disorder.

Adolescent↗
PubMed1993

1H NMR-based determination of the three-dimensional structure of the human plasma fibronectin fragment containing inter-chain disulfide bonds.

Human plasma fibronectin is a plasma glycoprotein that plays an important role in many biological processes. It consists of two identical 230-250-kDa subunits that are joined by two disulfide bonds near their carboxyl termini. Each subunit contains various binding domains composed of three types of homologous repeats. Recent work has determined the three-dimensional structures of various repeat fragments, but little is known about the three-dimensional structure of the carboxyl-terminal region. A recent NMR study of a plasmin-digested carboxyl-terminal inter-chain disulfide-linked heptapeptide dimer has proposed that the two subunits are arranged in an antiparallel fashion (An et al. (1992) Biochemistry 31, 9927-9933). We have now determined the three-dimensional structure for a substantial portion of a trypsin-digested interchain disulfide-linked 52-residue (6 kDa) fragment of the carboxyl-terminal of human plasma fibronectin (which includes the above-mentioned heptapeptide dimer) using two-dimensional NMR methods and a new strategy for NMR-based protein structure determination. The NMR data requires that the two chains in the dimer be linked in a symmetric, antiparallel arrangement. The resulting monomer conformation consists of two twisted or coiled segments, Thr3-Asn6 and Ile9-Phe12, connected by the Cys7-Pro8 residues in extended conformations, with the two monomer chains cross-linked at residues Cys7 and Cys11. The conformation of the heptapeptide dimer region differs substantially from the conformation proposed by An et al.

Amino Acid Sequence↗
PubMed1993

Trisomy in humans: incidence, origin and etiology.

Molecular studies conducted over the past year have demonstrated the importance of aberrant genetic recombination in the etiology of several human trisomies, and have begun to shed light on the basis of the association between advancing maternal age and trisomy. Preliminary studies of gametes using fluorescence in situ hybridization indicate that this will be a useful approach in the analysis of human non-disjunction.

Animals↗
PubMed1993

Prospective evaluation of endoscopic ultrasonography and endoscopic retrograde cholangiopancreatography in patients with chronic abdominal pain of suspected pancreatic origin.

Twenty asymptomatic paid volunteers (13 females, 7 males, mean age 34 years, range 21-52 years), underwent endoscopic ultrasonography (EUS) to assess variation in the appearance of ductular and parenchymal features of the pancreas. Following this investigation, 69 patients with chronic abdominal pain of suspected pancreaticobiliary origin were evaluated with EUS followed by endoscopic retrograde cholangiopancreatography (ERCP) and in 16 patients secretin stimulated intraductal pure pancreatic juice (PPJ) collection. Thirty patients were found to have chronic pancreatitis based on clinical, ERCP and/or PPJ data, and EUS was abnormal in 24 of these individuals. All of the 19 patients with abnormal pancreatograms also had an abnormal EUS. Twenty-two of the 30 patients with chronic pancreatitis had early disease (no or minimal changes on ERCP). In this subgroup of patients, the sensitivity of EUS was 86% versus 50% for ERCP (p = 0.01). For all patients, the sensitivity, specificity and accuracy of EUS in diagnosing chronic pancreatitis was 80%, 86% and 84% respectively. Using logistic regression analysis eight EUS features were found to be indicative of chronic pancreatitis including echogenic foci within the gland, focal regions of reduced echogenicity within the gland, increased thickness/echogenicity of the main pancreatic duct (MPD) wall, accentuation of the gland's lobular pattern, cysts, an irregular contour or dilation of the MPD and side branch dilation (p < or = 0.05). Generation of a receiver operating characteristic curve to assess the sensitivity and specificity of EUS in diagnosing chronic pancreatitis based on the number of abnormal findings demonstrated that sensitivity and specificity were optimal when three or more abnormal parenchymal and/or ductular features were found. These results suggest that EUS can play an adjunctive role to ERCP and PPJ in the diagnosis of early chronic pancreatitis.

Abdominal Pain↗
PubMed1993

Endoscopic management of biliary fistulas complicating liver transplantation and other hepatobiliary operations.

OBJECTIVE: This study was undertaken to prospectively evaluate the efficacy and safety of endoscopic management of biliary fistulas complicating liver transplantation and other hepatobiliary operations. SUMMARY BACKGROUND DATA: Surgical therapy has been the traditional approach to large or unresolving biliary fistulas complicating liver transplantation. Although endoscopic management is rapidly becoming an acceptable alternative to surgery for the treatment of biliary fistulas complicating non-liver transplant hepatobiliary operations, it has received limited attention in the liver transplant setting. METHODS: During a 15-month period, 146 adults underwent liver transplantation with biliary reconstruction by end-to-end choledochocholedochostomy over a T-tube. Inadvertent T-tube migration or intentional T-tube removal resulted in bile peritonitis in 18 patients. The patients were treated with a nasobiliary tube (n = 13), internal stent plus endoscopic sphincterotomy (n = 3), or internal stent alone (n = 2). Thirteen patients had a biliary fistula after other hepatobiliary operations and underwent endoscopic therapy during a similar period. All 13 had an endoscopic sphincterotomy with removal of obstructing stones when present (n = 6). Twelve patients also had stents placed. All patients were prospectively followed after hospital discharge and assessed for recurrent symptoms suggestive of biliary tract disease and procedure-related complications. RESULTS: Endoscopic retrograde cholangiopancreatography (ERCP) identified a biliary fistula at the T-tube insertion site into the bile duct in all 18 liver transplant patients. Seventeen patients had resolution of their symptoms within 12 hours of therapy. The fistula sealed in 94.4%. In the other hepatobiliary operation group, ERCP demonstrated contrast extravasation from the biliary tree in 12 of 13. The biliary fistula closure rate was 92.3%. The endoscopic complication rate for the two groups was 3.2%. During a mean follow-up of 9 months, recurrent biliary tract complications occurred in 11.1% of the liver transplant group and 0% in the other hepatobiliary operation group (p > 0.05). The 30-day mortality rate was 0%. CONCLUSIONS: The results of this study support the application of endoscopic management of biliary fistulas complicating orthotopic liver transplantation and other hepatobiliary operations. This approach was relatively safe and obviated the need for surgical intervention.

Adolescent↗
PubMed1993

Racial differences in the relationship between blood pressure and risk of retinopathy among individuals with NIDDM.

OBJECTIVE: To assess whether the prevalence of retinopathy differs between blacks and whites with diabetes and to examine differences between blacks and whites in the relationship between risk factors for and prevalence of retinopathy. Population data suggest diabetic retinopathy is either more prevalent or more severe in blacks than in whites. RESEARCH DESIGN AND METHODS: We analyzed data from a screening study for retinopathy among patients with diabetes, conducted in Maryland from 1986-1990. RESULTS: After adjusting for age, duration of diabetes, type of treatment for diabetes, and presence or absence of high blood pressure, black men with NIDDM were approximately 23% more likely to have retinopathy than other race-sex groups (not statistically significant). We also found a different relationship between systolic blood pressure and retinopathy prevalence in blacks than in whites among individuals with NIDDM. Among blacks, the risk increased as systolic blood pressure increased, even within the normal range, and reached statistical significance at > 150 mmHg. Among whites, the risk was increased only among those with high systolic blood pressure (> 140 mmHg) and did not reach statistical significance. CONCLUSIONS: Our data are consistent with the hypothesis that differences exist between blacks and whites in risk of diabetic retinopathy, and that the effect of blood pressure on risk of retinopathy differs between blacks and whites.

Adult↗
PubMed1993

Endoscopic therapy of pancreatic disease.

Endoscopic management of a variety of benign and malignant biliary tract diseases is now a well-established alternative to surgery. Similar techniques are beginning to be applied to the pancreas. Endoscopic therapy is now being utilized in the setting of acute pancreatitis, chronic pancreatitis, complications of pancreatitis, and pancreas divisum. In this review, we will analyze the current state of the art of these exciting new applications of endoscopy. Selection of appropriate candidates for the various treatment modalities appears important for optimal results of therapy. However, definite recommendations are difficult to make because there are few controlled studies, follow-up in most series is brief, and there are no comparison studies of endoscopic versus surgical therapy. At present, conservatism is the appropriate general rule in these therapeutic endeavors.

Acute Disease↗