Performance of Cepheid ® Xpert MTB/RIF ® and TB-Biochip ® MDR in two regions of Russia with a high prevalence of drug-resistant tuberculosis.

The purpose of this study was to assess the performance of Cepheid® Xpert MTB/RIF® ("Xpert") and TB-Biochip® MDR ("TB-Biochip"). Sputum specimens from adults with presumptive tuberculosis (TB) were homogenized and split for: (1) direct Xpert and microscopy, and (2) concentration for Xpert, microscopy, culture [Lowenstein-Jensen (LJ) solid media and Mycobacteria Growth Indicator Tube® (MGIT)], indirect drug susceptibility testing (DST) using the absolute concentration method and MGIT, and TB-Biochip. In total, 109 of 238 (45.8 %) specimens were culture-positive for Mycobacterium tuberculosis complex (MTBC), and, of these, 67 isolates were rifampicin resistant (RIF-R) by phenotypic DST and 64/67 (95.5 %) were isoniazid resistant (INH-R). Compared to culture of the same specimen, a single direct Xpert was more sensitive for detecting MTBC [95.3 %, 95 % confidence interval (CI), 90.0-98.3 %] than direct (59.6 %, 95 % CI, 50.2-68.5 %) or concentrated smear (85.3 %, 95 % CI, 77.7-91.1 %) or LJ culture (80.8 %, 95 % CI, 72.4-87.5 %); the specificity was 86.0 % (95 % CI, 78.9-91.3 %). Compared with MGIT DST, Xpert correctly identified 98.2 % (95 % CI, 91.5-99.9 %) of RIF-R and 95.5 % (95 % CI, 85.8-99.2 %) of RIF-susceptible (RIF-S) specimens. In a subset of 104 specimens, the sensitivity of TB-Biochip for MTBC detection compared to culture was 97.3 % (95 % CI, 91.0-99.5 %); the specificity was 78.1 % (95 % CI, 61.5-89.9 %). TB-Biochip correctly identified 100 % (95 % CI, 94.2-100 %) of RIF-R, 94.7 % (95 % CI, 76.7-99.7 %) of RIF-S, 98.2 % (95 % CI, 91.4-99.9 %) of INH-R, and 78.6 % (95 % CI, 52.1-94.2 %) of INH-S specimens compared to MGIT DST. Xpert and Biochip were similar in accuracy for detecting MTBC and RIF resistance compared to conventional culture methods.

Phase transition driven discontinuity in thermodynamic size selection.

We show how an order-disorder phase transition in a two-dimensional system can discontinuously alter the shape and size of stress-stabilized self-assembled nanostructures. Low energy electron microscopy was used to study the dealloying of the Cu(111)-sqrt[3]×sqrt[3]-R30°-Bi surface alloy. The gradual expulsion of embedded bismuth from the alloy with increasing temperature induces a hard-hexagon-type order-disorder transition in the surface alloy. Our low energy electron microscopy results demonstrate how the loss of long-range order induces enormous changes in the domain patterns that the alloy forms with a Bi overlayer phase. We propose that the occurrence of phase transitions in one of the two surface phases that constitute a self-assembled domain pattern, provides a general, largely unexplored, mechanism that can be used to influence the morphological details of two-dimensional nanostructures.

Augmentation of murine natural killer activity after culture.

The augmentation of murine natural killer (NK) cell activity after culture is described. Increased NK cell activity occurred when spleen cells were cultured for 18 or 42 h at high cell density in macro culture plates at 37 degrees C. Similar results were also achieved using the same cell density when micro culture plates were employed. The simple modifications of culture conditions described in this paper should provide an excellent tool to study murine NK activity after culture. Furthermore, the micro culture system has the added advantage of enabling one to test large numbers of samples.

The effect of FK506 on canine bile flow.

While the primary immunosuppressive agents utilized in solid-organ transplantation are steroids and cyclosporine, the more recently introduced agent FK506 is assuming a progressively more important role as an immunosuppressant, particularly in liver transplantation. While the effect of cyclosporine on rat and canine bile flow has been well evaluated, no information is available regarding the effect of FK506 on bile flow. Dogs with chronic biliary fistulas were utilized, enabling unanesthetized animals to be studied. FK506 was administered intravenously in varying doses, and bile volume, bile salts, and bile electrolytes were measured. FK506 produced dose-related increases in bile volume and bile chloride concentration and output, with 8 micrograms/kg-1hr-1 being the maximal dose. To ascertain that the response was not osmotic in association with FK506 secretion in bile, 500 micrograms/kg-1hr-1 FK506 was administered, which did not produce a choleresis significantly greater than 8 micrograms/kg-1hr-1. FK506 was subsequently administered orally in daily dose of 0.15 mg/kg-1 for two weeks. Oral FK506 did not consistently increase bile flow, as evaluated by a bile salt dose-response curve (9, 18, 36 mumol/min sodium taurocholate) but did significantly increase bile chloride secretion. Two weeks of oral administration of FK506 in therapeutic doses did not significantly alter serum bile salt concentrations. The results of this study indicate that intravenous FK506 produces a chloride-rich choleresis in dogs.

Evidence that 3,3',5-triiodothyronine is concentrated in and delivered from the locus coeruleus to its noradrenergic targets via anterograde axonal transport.

Recent immunohistochemical studies of rat brain triiodothyronine reveal heaviest localization in locus coeruleus perikarya. The cellular distribution is similar to that observed in concomitant studies of tyrosine hydroxylase immunohistochemistry: heavy clumps of immunoreactive triiodothyronine are distributed within locus coeruleus cytosol and in cell processes, leaving cell nuclei unstained. At the same time, in locus coeruleus targets, cell nuclei as well as surrounding neuropil are prominently triiodothyronine labeled. These observations, combined with diverse evidence linking thyroid hormone with norepinephrine at many levels of physiological and pathophysiological function, led to the hypothesis that the locus coeruleus binds and accumulates triiodothyronine and delivers the hormone via anterograde axonal transport to postsynaptic locus coeruleus targets, where nuclear triiodothyronine receptors are densely concentrated. Furthermore, the hypothesis predicts that destruction of locus coeruleus nerve terminals would interrupt this neural route of triiodothyronine delivery and prevent or reduce triiodothyronine labeling of nuclear receptors in noradrenergic target cells. To test this formulation, we gave the specific locus coeruleus lesioning agent, N-(2-chloroethyl)-N-2-bromobenzylamine hydrochloride (DSP-4), to adult male rats and examined their brains three, five and seven days thereafter by triiodothyronine and, in alternate sections, tyrosine hydroxylase immunohistochemistry. Treatment with DSP-4 resulted in specific and selective reduction in tyrosine hydroxylase and triiodothyronine immunohistochemical labeling in cell nuclei and in nerve cell processes within the neuropil of the hippocampus and cerebral cortex at all time periods examined. The results demonstrate that full occupancy of locus coeruleus target cells by triiodothyronine requires the presence of intact locus coeruleus projections and supports the proposal that, like norepinephrine, triiodothyronine delivery to noradrenergic targets occurs through delivery by locus coeruleus terminals. These findings provide strong support for earlier proposals that triiodothyronine functions as a co-transmitter with norepinephrine in addition to or as part of its genomic role in the cells receiving noradrenergic innervation.

Incidence of nocturnal desaturation while breathing oxygen in COPD patients undergoing long-term oxygen therapy.

STUDY OBJECTIVE: It is suggested that oxygen flow be increased by 1 L/min during sleep in COPD patients undergoing long-term oxygen therapy (LTOT) in order to avoid nocturnal desaturations. The purpose of this study was to investigate the occurrence of nocturnal desaturations while breathing oxygen in COPD patients receiving LTOT. SETTING: Inpatient/university hospital. PATIENTS: We studied 82 consecutive COPD patients. Their functional characteristics were as follows (mean +/- SD): FVC, 2.15 +/- 0.69 L; FEV(1), 0.87 +/- 0.33 L; PaO(2), 51.6 +/- 5 mm Hg; and PaCO(2), 47 +/- 8 mm Hg. MEASUREMENTS: Overnight pulse oximetry (PO) was performed twice: (1) while breathing air and (2) while breathing supplemental oxygen assuring satisfactory diurnal resting oxygenation (mean PaO(2) during oxygen breathing, 67 +/- 6 mm Hg; mean arterial oxygen saturation [SaO(2)] during oxygen breathing, 93%). RESULTS: PO performed while patients were breathing air showed a mean overnight SaO(2) of 82.7 +/- 6.7%. Patients spent 90% of the recording time with an SaO(2) of < 90%. While breathing oxygen, 43 patients (52.4%) remained well oxygenated. Their mean overnight SaO(2) while breathing oxygen was 94.4 +/- 2.1%, and time spent with saturation < 90% was 6.9 +/- 8.6%. Thirty-nine patients (47.6%) spent > 30% of the night with an SaO(2) of < 90% while breathing supplemental oxygen. Their mean overnight SaO(2) while breathing oxygen was 87.1 +/- 4.5%, and time spent with an SaO(2) of < 90% was 66.1 +/- 24.7% of the recording time. Comparison of ventilatory variables and daytime blood gases between both groups revealed statistically significantly higher PaCO(2) on air (p < 0.001) and on oxygen (p < 0. 05), and lower PaO(2) on oxygen (p < 0.05) in the group of patients demonstrating significant nocturnal desaturation. CONCLUSIONS: We conclude that about half of COPD patients undergoing LTOT need increased oxygen flow during sleep. Patients with both hypercapnia (PaCO(2) > or = 45 mm Hg) and PaO(2) < 65 mm Hg while breathing oxygen are most likely to desaturate during sleep.

The effect of vagotomy on the canine enterogastrone mechanism.

The effect of truncal vagotomy on the enterogastrone mechanism was evaluated in dogs with Heidenhain pouches and gastric and pancreatic fistulas. During continuous infusion of pentagastrin, 8 microg-Kg.-hr., HCl was infused into the duodenum in doses of 12, 18, and 24 mEq. per hour before and one month following transthoracic vagotomy. The effect of vagotomy on the inhibition of pentagastrin-stimulated Heidenhain pouch hydrogen ion output produced by the endogenous release of duodenal hormones was evaluated. The results indicate that there was no difference in the degree of inhibition produced by 12 and 18 mEq. intraduodenal HCl before and after vagotomy. When 24 mEq. per hour HCl was infused, the percent inhibition was significantly greater after vagotomy compared to values before vagotomy. The D50 of intraduodenal acid for inhibition of Heidenhain pouch hydrogen ion output was not altered by vagotomy, whereas the calculated maximal response (inhibition) was increased after vagotomy. Pancreatic volume was greater after vagotomy when compared to values before vagotomy, when 24 mEq. of HCl per hour was infused into the duodenum. These data suggest that vagotomy does not impair the effectiveness of the enterogastrone mechanism and at high doses of intraduodenal acid may augment it.

Significance of the in-training examination in a surgical residency program.

The exact role that the American Board of Surgery In-Training Examination plays in resident evaluation remains poorly defined. We have required that all residents take the In-Training Examination annually. An analysis was performed of the results of the In-Training Examination and the Qualifying Examination of the American Board of Surgery for 16 residents who completed their residencies between July 1976 and July 1981. Twelve graduates passed their initial Qualifying Examinations with a mean +/- 1 SEM score of 81 +/- 2. Four graduates failed with a score of 70 +/- 0.3. Corresponding scores on their final In-Training Examinations were 42 +/- 9 and 11 +/- 6 (p less than 0.001). Each year the In-Training Examination Scores obtained by the residents who passed the Qualifying Examination were significantly higher than were those scores obtained by the graduates who failed. Linear regression analysis identified a significant correlation between the graduates' initial (r = 0.676) and final (r = 0.760) In-Training Examination scores and the Qualifying Examination score. In our resident training program, In-Training Examination results correlated well with Qualifying Examination results and may be used as an objective determinant for remedial measures and resident retentions. These data should be developed on a national level. While Board certification was or likely will be accomplished by all our residents, our goal is to strengthen the academic characteristics of the training program to produce uniform success on the initial Qualifying Examination.

Comparative evaluation of synthetic meshes used for abdominal wall replacement.

The lack of adequate fascia for closure of large hernias and traumatic abdominal wall defects has led to a search for suitable fascial substitutes. In this study closure of rabbit abdominal wall defects with knitted polypropylene, knitted polytetrafluoroethylene (PTFE), and molded polyglactin mesh was evaluated for bursting strength, fibrous tissue incorporation, and inflammatory reaction. Full-thickness, inch-square defects in the abdominal walls of rabbits were closed with use of the synthetic meshes, and similar defects in the contralateral abdominal walls were closed with a vascularized flap of external oblique fascia (control flaps). The animals were sacrificed at 3 and 12 weeks, the abdominal walls were removed, and the bursting strength of the grafts and control flaps was determined with a tissue tensometer. Polypropylene and PTFE meshes were similar in bursting strength and not greatly different from controls at 3 and 12 weeks. At 3 weeks polyglactin mesh had a bursting strength comparable to that of control flaps but at 12 weeks was significantly weaker. Fibrous tissue incorporation within the mesh fibers was better with PTFE mesh than with polypropylene mesh. Adequate fibrous tissue incorporation into polyglactin mesh before hydrolysis did not occur, making it an unsatisfactory material for use for permanent abdominal wall replacement.

The effects of reversal of jejunoileal bypass operations on hepatic triglyceride content and hepatic morphology.

Obesity is associated with significant hepatic steatosis, inflammation, and cirrhosis. These changes may be accentuated by jejunoileal bypass operations. This study is intended to determine if reconstruction of jejunoileal bypass operations alters hepatic triglyceride content and hepatic morphology. Eighty-eight +/- 27 months after jejunoileal bypass, 26 patients underwent reconstruction for a variety of complications of the operation, including five patients with cirrhosis. At the time of reconstruction, hepatic triglyceride content was 132 +/- 13 mg/100 mg protein. After reconstruction, hepatic triglyceride content increased to 205 +/- 32 mg/100 mg protein in patients whose body weight increased and decreased to 84 +/- 6 mg/100 mg protein in patients whose body weight decreased. After reconstruction, hepatic inflammation decreased in 20 patients and hepatic fibrosis decreased in 17. These changes were not related to body weight changes. In five patients with cirrhosis at the time of reconstruction, one died of liver failure and hepatic morphologic findings improved in four after reconstruction of jejunoileal bypass operations. The results of this study suggest that reconstruction of jejunoileal bypass operations with weight loss or maintenance of body weight after reconstruction is associated with decreased fat in the liver. Approximately 65% of the patients will have improvement in hepatic morphologic parameters after reconstruction. Inflammation will be more greatly benefited than will fibrosis. In some patients, hepatic histologic abnormalities are unchanged or will progress despite reconstruction of jejunoileal bypass operations.

The role of prostaglandins in feline experimental cholecystitis.

The arachidonic acid metabolites are recognized as important biochemical mediators of inflammation in a wide variety of disease processes. Also the ability to change prostaglandin formation by inhibition of prostaglandin synthetase activity with aspirin and other nonsteroidal anti-inflammatory agents is important in the treatment of many diseases with an inflammatory component. Although gallbladder disease is primarily related to the development of cholesterol stones, inflammation is an important contributor to the subsequent symptoms and accompanying illness. This research evaluates the formation of prostaglandins E and F by gallbladder tissue. Gallbladder mucosal cells and muscle tissue were maintained in tissue culture medium. Production of prostaglandins E and F was determined by quantitation by radioimmunoassay of these substances in culture media and mucosal cell and muscle tissue homogenates. Prostaglandin production by normal gallbladder tissue in a variety of species including man was consistently demonstrated in the nanogram per milligram mucosal cell or muscle tissue protein range. In cats, inflammation was produced by placing a 4% carrageenan-soaked sponge in the gallbladder, and prostaglandin synthetase inhibition was produced by indomethacin administration. The feline gallbladder increased prostaglandin F production in inflamed gallbladder mucosal cells and E production by inflamed gallbladder muscle tissue, and indomethacin inhibited these increases. A positive, significant correlation existed between the increased prostaglandin E and prostaglandin F production by inflamed gallbladder tissue and the amount of inflammation present as determined by a histologic score. The histologic score of the amount of gallbladder inflammation present was decreased significantly by indomethacin when compared with inflamed gallbladders from cats not receiving indomethacin. Prostaglandins may play a role in the inflammatory processes occurring in acute cholecystitis.

The effect of cholecystokinin-receptor antagonists on cholecystokinin-stimulated bile flow in dogs.

Cholecystokinin is a choleretic in dogs. Some of the effects of cholecystokinin in stimulating bile flow in dogs are produced by cholecystokinin stimulating the release of other choleretic hormones such as insulin and glucagon. The purpose of this study was to determine the effects of cholecystokinin receptor antagonists on canine hepatic bile flow and insulin and glucagon release from the pancreas. Cholecystokinin octapeptide (CCK-8) and intraduodenal fat were administered to dogs that had undergone cholecystectomy with chronic biliary fistulas with and without the administration of cholecystokinin receptor antagonists. Bile secretion and systemic venous insulin, glucagon, and cholecystokinin levels were measured. The cholecystokinin receptor antagonists benzotript and CR 1409 had no effect on bile flow or hormone levels when administered without cholecystokinin, whereas proglumide produced a large increase in bile flow without altering hormone levels. The response produced by proglumide may be the result of an osmotic effect produced by the substance being secreted in bile and its stimulating bile salt secretion in bile. CCK-8 and intraduodenal fat increased bile flow, bile chloride secretion, and cholecystokinin, insulin, and glucagon concentrations in venous blood. The cholecystokinin receptor antagonists benzotript and CR 1409 significantly decreased the bile flow and insulin and glucagon changes produced by exogenous CCK-8. The effect of intraduodenal fat on bile flow was not inhibited by the cholecystokinin receptor antagonists, whereas the increased insulin and glucagon levels were decreased significantly. Intraduodenal fat may release other choleretic hormones not affected by cholecystokinin receptor antagonists. The choleresis produced by exogenous CCK-8 is inhibited by cholecystokinin receptor antagonists, perhaps by inhibiting the release of the choleretic hormones insulin and glucagon.

The effect of electrical vagal stimulation on canine pancreatic exocrine function.

The effect of electrical vagal stimulation on canine pancreatic exocrine function was studied in conscious dogs by stimulating intact thoracic vagus nerves, the distal ends of cut vagus nerves in animals with intact gastric denervation, and the distal ends of cut vagus nerves in dogs whose stomachs had been previously selectively denervated. The effectiveness of the stimulus was confirmed by monitoring gastric hydrogen ion output. The results indicate that stimulation of intact nerves produced minimal alteration in pancreatic output and bicarbonate and protein secretion while significantly increasing gastric fistula hydrogen ion output. Stimulation of the distal ends (efferent fibers) of cut vagus nerves in dogs with intact gastric innervation significantly increased the volume and protein output of the pancreas and the acid output of the stomach. Stimulation of the distal ends of cut right and both vagus nerves in dogs whose stomach had been denervated previously, again, significantly increased the volume and protein output of the pancreas without stimulation of stomach hydrogen ion output. The data presented in this study suggest that the canine pancreas is innervated directly by vagal fibers, which when stimulated produce an increase in protein (enzyme) output and volume of secretion. Maintenance of the pancreatic response following denervation of the stomach suggests that the response is primarily the result of direct vagal innervation and is not produced by gastrin released from the antrum.

Evaluations of surgery resident performance correlate with success in board examinations.

BACKGROUND: American Board of Surgery (ABS) In-Training Examination (ABSITE) scores correlate with future examination scores, but faculty evaluations of resident skill have not been shown to predict future performance. METHODS: Objective and subjective evaluations during the past 15 years in our columnar university surgical residency were reviewed to assess their ability to predict success on the qualifying (written) and oral (certifying) examinations offered by the ABS. RESULTS: The ABSITE scores correlated with success on the qualifying examination (multiple R2 = 0.473). Subjective assessments of resident knowledge at any level did not correlate with ABSITE or qualifying scores, but above average scores did predict success on the certifying examination (chi 2, p < 0.005). Chief-year ABSITE total percentile score and score of first qualifying examination also predicted success on the certifying examination. The attrition rate in our nonpyramidal program was 23%, of which more than one half were voluntary. One of 11 residents leaving the program has subsequently attained ABS certification. CONCLUSIONS: This study shows that faculty's subjective evaluations predicted resident success on the ABS certifying examination and also endorses the ABS oral examination as an effective measure of the candidate's ability to communicate surgical knowledge.

Comparison of minimally invasive methods of parietal cell vagotomy in a porcine model.

BACKGROUND: Parietal cell vagotomy (PCV) is an accepted therapy for peptic ulcer disease. Traditional operative PCV results may be obtained laparoscopically or endoscopically. The purpose of this study was to quantitatively evaluate newer methods of PCV. METHODS: Variations in PCV, gastroscopic chemoneurolysis and laparoscopic photoneurolysis, were evaluated in 20 to 25 kg pigs. Traditional operative PCV was performed by laparotomy and served as the operative control. With a posterior truncal vagotomy, a PCV was performed laparoscopically by an anterior seromyotomy with either operative division of the neurovascular bundles with titanium clips or with a defocused CO2 laser. Transesophageal gastroscopic PCV was performed by transmucosal injections of the chemoneurolytic agents, 0.75% cobaltous chloride or 0.1% benzalkonium chloride. Adequacy of PCV at the time of operation was assessed by endoscopic Congo red testing. Two weeks later, repeat Congo red testing was performed by open gastrotomy. Quantitation of completeness of PCV and statistical comparison was determined by photographing the pentagastrin-stimulated gastric mucosa 5 minutes after Congo red application and subsequent comparison of innervated area versus total gastric mucosal area by a computer-driven digitized area-calculation program. RESULTS: All PCV techniques studied produced significant acid-secretory reduction, and both laparoscopic and gastroscopic PCV denervated the parietal cells in a manner comparable with operative PCV. Laser photoneurolysis could only be accomplished by producing full-thickness necrosis of the gastric wall. Submucosal injection of cobaltous chloride produced granulomatous nodules with foreign body crystals. Unlike operative and laparoscopic PCV, transmucosal gastroscopic benzalkonium PCV did not produce gross gastroparesis. CONCLUSIONS: All evaluated laparoscopic and endoscopic PCV techniques effectively denervated the parietal cells of the porcine stomach when evaluated at 2 weeks after treatment. Gastroscopic submucosal injection of benzalkonium chloride produced effective denervation with no evident histologic tissue changes and suggestive evidence of normal gastric emptying. Further evaluation with more extended periods of observation of these new techniques of performing PCV appear warranted.

Evaluation of intragastric pH in acutely ill patients.

The effect of various modalities on maintaining a high intragastric pH in acutely ill patients was evaluated. Twelve patients with one or more organ system failures had the effect of nasogastric suction, intragastric antacid instillation, and intravenous cimetidine administration on intragastric pH determined by an indwelling, intragastric pH probe. Each therapeutic modality was administered for 12 hours and the order of performance randomized. Nasogastric suction was associated with a constant intragastric pH of less than 2.0. Mean intragastric pH with cimetidine administration was significantly higher than with antacid administration and consistently greater than 5.0. If low intragastric pH represents susceptibility to acute mucosal lesions, cimetidine therapy was more effective than antacids in the doses and frequency of administration used in this study in maintaining a high intragastric pH, and it may be effective in preventing stress ulcer formation.

Segmental hepatic resection utilizing the ultrasonic dissector.

Hepatic resection continues to become a more widely accepted therapeutic modality, with increased use as improved imaging modalities more precisely define the nature and extent of various liver abnormalities. The surgical anatomy of the liver indicates that there are eight segments with single or multiple segmental resections able to be performed. The use of the ultrasonic dissector facilitates the performance of transparenchymatous segmental resection without obtaining vascular inflow or outflow control. This report describes the segmental anatomy of the liver and the use of the ultrasonic dissector. Thirteen patients have undergone segmental hepatic resection with the ultrasonic dissector. Five patients had cirrhosis. Mean +/- 1 SD operative time required for segmental resection was 128 +/- 57 minutes, and blood loss was 830 +/- 623 mL. Utilization of the ultrasonic dissector to perform segmental hepatic resection may increase our versatility in the management of various hepatic and biliary tract diseases.

Comparative evaluation of educational methods in surgical resident education.

OBJECTIVE: To determine the influence of study methods on American Board of Surgery (ABS) examination performance. DESIGN: Performance on ABS examinations by and faculty evaluations of 54 categorical surgical residents from 1976 to 1992 were correlated with the residents' use of commonly available educational methods (textbooks, Selected Readings in General Surgery, grand rounds, preceptor guidance, clinical surgery review courses, surgical science review courses, Surgical Education and Self-Assessment Program [SESAP], and continuing medical education lectures) in early, late, and after residency. SETTING: An average-sized midwestern US university surgical residency. RESULTS: Residents who consistently scored above the 33rd percentile on ABS examinations had used texts early, Selected Readings later, and SESAP after residency more frequently than those with ABS In-Training Examination scores in the lower one third. Selected Readings and clinical review courses were associated with significant increases in ABS percentile scores when used in late or after residency and, along with SESAP, were used when residents improved their low ABS In-Training Examination scores. CONCLUSIONS: Independent study methods are the most effective pathway to successful ABS examination performance. Formal surgical review courses may help improve the ABS examination scores of residents at a higher risk of failure.

Evaluation of various techniques to monitor intragastric pH.

Recent reports emphasized the importance of maintenance of a high intragastric pH to prevent gastric mucosal bleeding in acutely ill patients. In this study gastric fluid pH determinations were compared with determinations obtained using an intragastric pH electrode. There was poor correlation between pH determinations obtained by a bare intragastric electrode in contact with the mucosa and pH determinations on fluid aspirated from the stomach. During cimetidine administration mucosal and fluid determinations correlated well, whereas during antacid administrations correlated well, whereas during antacid administration mucosal pH was significantly lower than gastric fluid pH. These results suggest that during antacid administration pH determinations on gastric contents with pH paper may not accurately reflect the pH at the mucosal surface.

Prognostic value of the monoethylglycinexylidide liver function test in assessing donor liver suitability.

BACKGROUND: Liver graft assessment prior to transplantation continues to be controversial. Various donor organ parameters must be evaluated to ensure that the transplanted organ will function and that the number of organs discarded will be minimized. Recent attempts to quantify liver function have utilized the metabolism of lidocaine to monoethylglycinexylidide (MEGX), and the MEGX test has been employed to evaluate the functional characteristics of donor livers prior to transplantation, with conflicting results. OBJECTIVE: To ascertain the role of quantitating the metabolic rate of lidocaine in predicting the results of liver transplantation. METHODS: Consecutive liver donors (N = 37) underwent quantitation of the amount of lidocaine converted to MEGX at 15 minutes. The donor patients were divided arbitrarily into efficient and poor lidocaine metabolizers, and the results of liver transplantation were evaluated. RESULTS: Patients who received livers that produced MEGX values of 80 ng/mL or less in 15 minutes had no definable alteration in transplantation outcome compared with patients who received livers that were more efficient lidocaine metabolizers. In a collected series, 46 patients who received livers that produced MEGX values of 80 ng/mL or less had a 1-month graft survival rate of 89% (41/46), while 74 patients who received livers that produced MEGX values greater than 80 ng/mL had a 1-month graft survival rate of 86% (64/74). CONCLUSIONS: The MEGX test had no practical utility in predicting liver graft functional status.