Evaluation of clinical skills for first-year surgical residents using orientation programme and objective structured clinical evaluation as a tool of assessment.

BACKGROUND: Postgraduate specialities require a combination of knowledge and clinical skills. The internship year is less structured. Clinical and practical skills that are picked up during training are not well regulated and the impact is not assessed. In this study, we assessed knowledge and skills using objective structured clinical examination (OSCE). AIM: To evaluate the clinical skills of new first-year surgical residents using orientation programme and OSCE as a tool for assessment. SETTINGS AND DESIGN: Observational study. MATERIALS AND METHODS: Twenty new first-year surgical residents (10 each in 2008 and 2009) participated in a detailed structured orientation programme conducted over a period of 7 days. Clinically important topics and skills expected at this level (e.g., suturing, wound care etc.) were covered. The programme was preceded by an OSCE to test pre-programme knowledge (the "pre-test"). The questions were validated by senior department staff. A post-programme OSCE (the "post-test") helped to evaluate the change in clinical skill level brought about by the orientation programme. STATISTICAL ANALYSIS: Wilcoxson matched-pairs signed-ranks test. RESULTS: Passing performance was achieved by all participants in both pre- and post-tests. Following the orientation programme, significant improvement was seen in tasks testing the psychomotor and cognitive domains. (P = 0.0001 and P = 0.0401, respectively). Overall reliability of the OSCE was found to be 0.7026 (Cronbach's coefficient alpha). CONCLUSIONS: This study highlighted the lacunae in current internship training, especially for skill-based tasks. There is a need for universal inclusion of structured orientation programmes in the training of first-year residents. OSCE is a reliable, valid and effective method for the assessment of clinical skills.

UDP-glucuronosyltransferases in human intestinal mucosa.

While UDP-glucuronosyltransferases (UGTs) are known to be expressed at high levels in human liver, relatively little is known about extrahepatic expression. In the present study, UGT2B family isoforms involved in the glucuronidation of steroid hormones and bile acids have been characterized in microsomes prepared from jejunum, ileum and colon from six human subjects. Glucuronidation of androsterone and testosterone was highly significant and increased from proximal to distal intestine. In contrast, hyodeoxycholic acid was glucuronidated at a low level in jejunum and ileum and activity was barely detectable in colon. No significant glucuronidation of lithocholic acid was found. Small phenols were glucuronidated with much lower activity than found in liver. High levels of UGT protein were detected with polyclonal anti-rat androsterone- and testosterone-UGT antibodies, whereas UGT2B4, a major hepatic hyodeoxycholic acid-specific UGT, was undetectable using a highly specific anti-human UGT2B4 antibody. Screening for RNA expression by RT-PCR confirmed the absence of UGT2B4 and UGT1A6 and showed expression of UGT2B7, a hepatic isoform shown to glucuronidate androsterone, in all intestinal segments. To our knowledge, the presence of functional androsterone and testosterone directed isoforms in human intestine is a novel finding which supports the idea that the intestinal tract functions as a steroid-metabolizing organ and plays a significant role in steroid hormone biotransformation.

Identification of human hepatocyte protein(s), which binds specifically to the recombinant envelope-2/non-structural-1 protein of hepatitis C virus.

Hepatitis C virus (HCV), which is the major pathogen responsible for human chronic liver disease, has special tropism for hepatocytes. Although, low-density lipoprotein receptor, CD81 and negatively charged glycosaminoglycans have been proposed as candidate receptors for HCV, no confirmed receptor(s) on the hepatocytes have been identified to date. It is also suggested that additional, yet unidentified, cellular proteins may be involved in the host-viral interaction. Therefore, this study was conducted with the main aim to identify hepatocyte protein(s) that may have affinity for the HCV structural protein, envelope-2/non-structural-1 (E2/NS1) protein. For the binding studies, hepatocytes were isolated from fresh normal human liver tissues. The hepatocyte proteins on the nitrocellulose paper were reacted with recombinant E2/NS1 protein and anti-E2 (rabbit). In another approach, to rule out the possibility of binding of rec-E2/NS1 with the hepatocyte cytoplasmic proteins, hepatocyte plasma membrane proteins were passed through CNBr-activated and recombinant E2/NS1 bound sepharose-4B column. The recombinant E2/NS1 binding hepatocyte plasma membrane protein(s) were eluted and were then analyzed. Altogether, our data suggest that E2/NS1 protein of HCV binds to two hepatocyte proteins of molecular weights 25-28 kDa and 59-60 kDa. These results indicate the possible role of the above proteins (25-28 kDa and 59-60 kDa) in the viral binding to the hepatocytes.

PCB congener profile in the serum of humans consuming Great Lakes fish.

The State of Michigan has a long history of research into human exposure to environmental contaminants through consumption of recreationally caught fish. A large cohort of Lake Michigan residents who eat fish (fish-eaters) and those who do not eat fish (nonfish-eaters) established in 1980 served as the basis for the congener-specific polychlorinated biphenyl (PCB) exposure evaluation reported here. In this paper we present the serum PCB congener profile for a subset of this cohort who were over 50 years of age. Serum samples were collected in 1993-1995 and were evaluated by a dual column capillary column gas chromatography procedure capable of detecting over 90 PCB congeners. This evaluation demonstrated significant PCB exposure in the fish-eaters (mean serum PCB of 14.26 ppb; n = 101). This elevated exposure allowed the establishment of a detailed profile of the PCB congeners found in humans exposed by this route. Twenty-two congeners of varying concentrations were the most prevalent and constituted over 95% of the total PCB present in most subjects. Four congeners, 138/163 (2,2',3,4,4',5-PCB/2,3,3',4', 5,6-PCB), 180 (2,2',3,4,4',5,5'-PCB), and 153 (2,2',4,4',5,5'-PCB), accounted for 55-64% of the total PCB load. Other congeners, some of toxicologic significance, were also detected by this analytical protocol. Nonfish-eaters had lower total serum PCB levels (mean = 4. 56; n = 78), but the same general pattern of PCB congeners was present. It was demonstrated that careful selection of a subset of prevalent PCB congeners could provide a cost-effective assessment of exposure without losing critical scientific information.

Generation of reactive metabolites during spontaneous degradation of atracurium in vitro.

The hypothesis was tested in vitro that the spontaneous degradation of atracurium leads to formation of electrophilic metabolites. Variable amounts of atracurium were incubated in saline (0.9% NaCl) for 120 minutes at pH 8.0 and 37 degrees C. Subsequently, cysteine was added to the incubation solutions and the incubation was continued at pH 7.4 and 37 degrees C. Frequent determination of the mercapto groups of cysteine revealed a progressive diminution of the mercapto groups remaining in the incubation solutions. The consumption of sulfhydryl groups was maximal at 20 minutes after the addition of cysteine and amounted to approximately twice the molar amount of atracurium. Kinetic analysis indicated that one mercapto group was consumed almost instantly, whereas the consumption of the other proceeded with a half-life of 4 minutes. No consumption of mercapto groups was observed when laudanosine was incubated with cysteine. Incubation of atracurium or of its degradation products with carboxylesterase markedly reduced the amount of reactive metabolites present in the incubation solutions. The results are compatible with the working hypothesis that spontaneous degradation of atracurium via Hofmann elimination results in generation of two equivalents of reactive electrophilic esters, probably acrylates. We propose that in vivo the portion of the aliphatic chain in the atracurium molecule that is converted to acrylates by Hofmann elimination may be eliminated in part in urine as a conjugate of mercapturic acid.

Retroperitoneal teratoma presenting as acute abdomen in an elderly person.

A 56-year-old man presented with acute abdomen. Clinically, he was diagnosed as having perigastric abscess. On exploration, a retroperitoneal cystic teratoma was encountered. Postoperatively, he recovered uneventfully and has no residual disease two years later.

Expression and purification of E2/NS1 protein of hepatitis C virus and detection of anti-E2/NS1 antibodies in chronic liver disease patients.

Glycoproteins on the surface of viral particles present the main target of neutralizing antibodies. The structural proteins of most Flaviviruses are known to elicit neutralizing antibodies and, thus, to help in both the natural resolution of the infection and the protection from challenge with homologous hepatitis C virus (HCV). Because such antigens are associated with the viral clearance in both humans and chimpanzees, we aimed to express the E2/NS1 protein of HCV and to study the role of anti-E2/NS1 antibodies in the natural resolution of HCV infection. The prevalence of anti-E2/NS1 antibodies to recombinant E2/NS1 protein was seen by Western blot in chronic liver disease patients (15 chronic hepatitis and 12 cirrhotic patients), who were positive for anti-HCV and negative for HBV infection. The study also included 2 negative controls (positive for HBV infection and negative for anti-HCV antibodies) and 2 healthy controls (negative for both HBV and HCV infection). Anti-E2/NS1 was present in 20% of the chronic hepatitis and 16% of the cirrhosis patients. None of the controls were positive for anti-E2/NS1 antibodies. Serum samples positive for anti-E2/NS1 antibodies were also positive for HCV RNA by RT/PCR. Accordingly, the presence of anti-E2/NS1 may have very little or no role in the natural resolution of HCV infection.

Inactivation of atracurium in human and rat plasma.

The contribution of enzyme-catalyzed hydrolysis to inactivation of atracurium in human and rat plasma was determined in vitro by inhibiting the enzyme carboxylesterase with triorthotolyl phosphate. The inhibitor was removed by centrifugation and aspiration. Atracurium was then added to both the control and the inhibited plasma samples, and all samples were incubated at 37 degrees C for 45 min. The amount of atracurium present in aliquots of plasma was determined using a bioassay technique in anesthetized rats. Inactivation of atracurium proceeded rapidly in control rat plasma but was markedly slowed in samples treated with the inhibitor of carboxylesterase. In contrast, the inactivation was slow in control human plasma, and inhibition of carboxylesterase produced only marginal, if any, effects. We conclude that the inactivation of atracurium proceeds, in part, by enzyme-catalyzed ester hydrolysis. In species with high enzyme activity in plasma, e.g., the rat, enzyme-catalyzed hydrolysis is clearly evident. In humans, the level of enzyme activity is low and the contribution of enzyme-catalyzed inactivation is less manifest. By exclusion, Hofmann elimination or other reactions probably represent the major inactivation pathway in humans.

Circumcaval ureter.

We report a case of circumcaval ureter diagnosed preoperatively by 'fish-hook' appearance on intravenous pyelogram. At surgery, patient was treated by 'Anderson Hones' pyeloplasty leaving the retrocaval segment in-situ.

Anatomy of the human lumbar epidural space: new insights using CT-epidurography.

The anatomy of the lumbar epidural space was demonstrated in 40 patients by computed tomography (CT) examinations performed after epidural injection of noninonic radiographic contrast material into the sacral caudal canal via percutaneous catheter. Radiologic evaluation of the epidural space was performed to evaluate possible disc herniation or other pathologic encroachments on the epidural space. In all 40 patients, the examinations showed the posterior epidural space to be divided by the plica mediana dorsalis and an additional transverse connective tissue plane not previously described. The compartmentalized nature of the space may be, at times, responsible for entrapment and coiling of epidural catheters, despite satisfactory technical performance of catheterization for epidural anesthesia. Thirty-one of 40 patients demonstrated a greater amount of fatty tissue within the junctions of the posterior midline epidural connective tissue structures, producing a bulky triangular-shaped structure which might be an impediment to catheterization. The divisions of the anterior and posterior epidural spaces are seen to be more complex than previously described.

Reactivity and toxicity of atracurium and its metabolites in vitro.

Cytotoxicity of atracurium and of its metabolites was tested in vitro. Exposure of isolated rat hepatocytes to atracurium produced cellular damage evidenced by extrusion of an intracellular enzyme, lactate dehydrogenase (LDH), into the incubation medium. Leakage of LDH was directly related to the concentration of atracurium in the medium (250 to 800 microM). If the spontaneous degradation of atracurium (presumably via Hofmann elimination) was first carried out in vitro and the degradation products subsequently added to the isolated hepatocytes, the leakage of LDH was also dose-dependent but larger than that observed after the addition of the parent drug. When l-cysteine was admixed to the products of the spontaneous degradation of atracurium prior to their addition to the liver cells, no leakage of LDH was observed. The results are compatible with the working hypothesis that atracurium itself and, even more so, acrylates formed in Hofmann elimination of atracurium, are reactive toward nucleophiles and damage the cells by alkylating nucleophiles present in cellular membranes. Antecedent covalent binding of acrylates to the nucleophile cysteine, i.e., the formation of acrylate-cysteine adducts, saturated the reactive capacity of acrylates for nucleophiles and thus prevented the reactive metabolites from alkylating the endogenous nucleophiles. Possible clinical consequences resulting from in vivo generation of reactive metabolites are not clear at the present time but are projected to be related to (a) the dose of atracurium administered, (b) the amount of acrylates generated, (c) the functional importance of the endogenous nucleophiles alkylated, and (d) the pathway and the speed of detoxification of atracurium and its metabolites.

A systematic approach to the validation of process control parameters for monoclonal antibody production in fed-batch culture of a murine myeloma.

A systematic approach to the validation of control ranges of control parameters for a cell culture process producing a monoclonal antibody is described. Specifically, the structure and functional activity of a monoclonal IgG1 antibody produced at the outer limits of numerical ranges of fed-batch culture control parameters such as pH and temperature were examined, with the aim of providing assurance that antibody produced under varying culture conditions was of consistent quality based on a carefully defined set of specifications. An experimental design was created using a half-fractional factorial design for fed-batch culture incorporating half of the thirty two possible combinations of five selected control parameters at high and low levels. Statistical analysis of all data gathered from the study allowed an assessment of the effects of the process control parameters at either high or low outer limits on fed-batch culture response variables such as growth rate and specific antibody productivity. Measured values for the responses of growth rate and specific antibody productivity throughout this study ranged from 0.22-0.44 d(-1) and 6.4-32 microg monoclonal antibody/10(6) cells/d respectively. Analytical characterisation of monoclonal antibody purified from each fed-batch culture considered the purity, structure and biological activity of the glycoprotein. All antibody preparations were identical to each other and to the current antibody reference standard or control. Glycosylation analysis of certain samples from the study demonstrated that the distribution of glycoforms of the antibody was not affected by the varying process control conditions of the fed-batch cultures.