Directed sampling for electrolyte analysis and water content of micro-punch samples shows large differences between normal and ischemic rat brain cortex

Changes in sodium, potassium, and water content in brain tissue are important in the progression of pathology that follows ischemic stroke. Determining these parameters regionally in rodent models of experimental ischemia has been limited because typical tissue weights of more than 35 mg are too large. Identifying ischemic tissue to direct tissue sampling towards ischemic cortex is also represents a difficult generally unresolved area. We suggest that larger differences between normal and ischemic cortex of sodium, potassium, and water content than previously observed can be obtained from directed sampling of 2-mg brain tissue in a model of focal cerebral ischemia. In five rats, the middle cerebral artery and both common carotid arteries were occluded for 4.9+/-0.13 h (mean+/-SEM). Punch-sampling of 1-mm diameter tissue cores for water content (H(2)O%) by the wet-dry method, and [Na(+)] and [K(+)] by flame photometry, was guided by the observation of a subtle change in the surface reflectivity of ischemic cortex of quickly dried, 20-microm frozen brain sections, that was confirmed by MAP2 immunohistochemistry. The ratio of the lesion areas as determined by the reflective change and MAP2 immunoreactivity was 0.96+/-0.03 (n=5). In ischemic cortex H(2)O% was 79.9%+/-0.8%, [Na(+)] was 550+/-25 mEq/kg dry-weight, and [K(+)] 94.2+/-19.2 mEq/kg dry-weight (n=5), all significantly different from the values in border zone cortex, and in cortex contralateral to ischemic cortex and border zone (for all samples n=60, mean wet weight 2.037+/-0.046 mg). Differences between ischemic and normal cortex were 5.4+/-1.1%, 317+/-21 mEq/kg dry-weight, -304+/-27 mEq/kg dry-weight (n=5) for H(2)O%, [Na(+)], and [K(+)]. These differences between ischemic and normal cortex are 1.4-2.5, 1-3.11, and 1.4-3.5 times greater, respectively, than previous results obtained using samples weighing 35 mg or more. These results extend the association of sodium and potassium with ischemic brain edema in the rodent model, and show that these classical measurements can keep pace with the regionality of histochemical and morphological methods.     

Selective intraoperative cholangiography during laparoscopic cholecystectomy: how selective?

The necessity for intraoperative cholangiography during laparoscopic cholecystectomy has been debated for some time. Numerous retrospective studies favor selective intraoperative cholangiography. Surgeons in favor of the selective policy differ in their personal selective criteria. The aim of this prospective study was to evaluate whether intraoperative cholangiography can be safely omitted during laparoscopic cholecystectomy on all patients who fit a standard set of criteria: normal liver function tests, common bile duct diameter less than 10 mm, and no history of gallstone pancreatitis or jaundice. We undertook a prospective study on 155 consecutive patients treated in a county teaching hospital with symptomatic gallbladder disease who met the above standard set of criteria. One hundred and fifty-five patients meeting these criteria underwent laparoscopic cholecystectomy during a 2-year period from February 1996 through February 1998. Data analyzed included patient history, laboratory and ultrasound findings, operative results, postoperative stay, and intraoperative and postoperative complications. The patients were followed by periodic interviews, physical examination, liver function tests, and/or biliary ultrasound for up to 3 1/2 years with a mean follow-up of 26 months for retained common bile duct stones. Intraoperative cholangiography was performed in only one of the 155 patients studied to confirm common bile duct injury. There were four postoperative complications (2.6%) and one common bile injury (0.6%). Postoperative stay averaged one day. No patients, by history, biliary ultrasound, liver function tests or endoscopy, were found to have retained common bile duct stones during the follow-up period. Our study shows that intraoperative cholangiography is not necessary for patients undergoing laparoscopic cholecystectomy who have normal liver functions tests, common bile duct diameter less than 10 mm, and no history of gallstone pancreatitis or jaundice.     

Cost savings associated with changes in routine laboratory tests ordered for victims of trauma

Not all trauma victims evaluated by the trauma service require a full complement of laboratory tests upon admission. This study set out to determine the cost savings and safety of limited laboratory testing of trauma victims. Before 1998, our admission trauma protocol included 11 laboratory tests for all trauma victims. In 1998, we created two categories: Trauma Blue--severe injury likely (Glasgow Coma Score <13; systolic blood pressure <100 mm Hg at any time; significant head, chest, abdominal, or proximal long bone injury; or clinical suspicion of need for operative or intensive care unit management) and Trauma Yellow--severe injury unlikely. The triage decision was made by the team leader or attending physician. Trauma Blue laboratory tests included an arterial blood gas, blood alcohol, type and screen or crossmatch, and urine dipstick. All patients who did not meet Trauma Blue criteria were entered in the Trauma Yellow group. There were only two tests for the Trauma Yellow group, a venous blood gas and blood alcohol. All arterial and venous blood gases measured pH, pO2, pCO2, HCO3, base deficit, hemoglobin, sodium, potassium, and ionized calcium. Other laboratory tests were done if requested by the trauma team leader or attending physician. All trauma admissions for a 3-month period were entered into this prospective study. The admitting trauma surgeon was surveyed after each admission to evaluate any problems in patient care. The test group was compared with a historical control of 100 consecutive patients under the original laboratory trauma protocol. One hundred and forty-eight (148) patients were entered into the study. Average laboratory cost per patient was $29.82 less with the study protocol. No patient care problem was identified. A cost savings of $29.82 per patient or $20,000.00 a year was realized for our institution, with no change in the quality of patient care. Trauma protocols designed to reflect a patient's potential for serious injury can result in a significant cost savings while preserving patient safety.     

Electrochemical lesions in the rat liver support its potential for treatment of liver tumors

BACKGROUND: An effective therapy is needed for patients with surgically unresectable liver tumors who have very limited life expectancy. One possible treatment is electrochemical tumor necrosis. This study investigated the natural history of electrochemical lesions in the normal rat liver. MATERIALS AND METHODS: A direct current generator, connected to platinum electrodes, was used to create controlled areas of liver necrosis. Animals were sacrificed 2 days, 2 weeks, 2 months, and 6 months after treatment and the macroscopic and histological appearance of the necrotic lesions was followed. RESULTS: No animal died as a result of electrolysis; postoperatively, all gained weight normally. Liver enzymes were significantly (P < 0.001) elevated after treatment, but returned to normal after a week. Two days after electrolysis, histology confirmed an ellipsoidal area of coagulative necrosis at the site of the electrode tip and commonly a segment of peripheral necrosis. After 2 weeks there was histological evidence of healing. By 6 months, very little necrotic tissue remained within a small fibrous scar. CONCLUSIONS: Electrolysis is a safe method for creating defined areas of liver necrosis that heal well with no associated mortality. This study supports the potential of electrolysis for treating patients with unresectable liver tumors.     

Vascular endothelial growth factor and basic fibroblast growth factor in children with cyanotic congenital heart disease

OBJECTIVE: Vascular endothelial growth factor and basic fibroblast growth factor are potent stimulators of angiogenesis. Children with cyanotic congenital heart disease often experience the development of widespread formation of collateral blood vessels, which may represent a form of abnormal angiogenesis. We undertook the present study to determine whether children with cyanotic congenital heart disease have elevated serum levels of vascular endothelial growth factor and basic fibroblast growth factor. METHODS: Serum was obtained from 22 children with cyanotic congenital heart disease and 19 children with acyanotic heart disease during cardiac catheterization. Samples were taken from the superior vena cava, inferior vena cava, and a systemic artery. Vascular endothelial growth factor and basic fibroblast growth factor levels were measured in the serum from each of these sites by enzyme-linked immunosorbent assay. RESULTS: Vascular endothelial growth factor was significantly elevated in the superior vena cava (P =.04) and systemic artery (P =.02) but not in the inferior vena cava (P =.2) of children with cyanotic congenital heart disease compared to children with acyanotic heart disease. The mean vascular endothelial growth factor level, determined by averaging the means of all 3 sites, was also significantly elevated (P =.03). Basic fibroblast growth factor was only significantly elevated in the systemic artery (P =.02). CONCLUSION: Children with cyanotic congenital heart disease have elevated systemic levels of vascular endothelial growth factor. These findings suggest that the widespread formation of collateral vessels in these children may be mediated by vascular endothelial growth factor.     

Beacon: a novel gene involved in the regulation of energy balance

The hypothalamus plays a major role in the control of energy balance via the coordination of several neuropeptides and their receptors. We used a unique polygenic animal model of obesity, Psammomys obesus, and performed differential display polymerase chain reaction on hypothalamic mRNA samples to identify novel genes involved in obesity. In this study, we describe a novel gene that encodes a small protein we have termed "beacon." Beacon mRNA gene expression in the hypothalamus was positively correlated with percentage of body fat. Intracerebroventricular infusion of beacon resulted in a dose-dependent increase in food intake and body weight and an increase in hypothalamic expression of neuropeptide Y (NPY). Simultaneous infusion of beacon and NPY significantly potentiated the orexigenic response and resulted in rapid body weight gain. These data suggest a role for beacon in the regulation of energy balance and body weight homeostasis that may be mediated, at least in part, through the NPY pathway.     

Practices in public health finance: an investigation of jurisdiction funding patterns and performance.

A field of study for public health finance has never been adequately developed. Consequently, very little is known about the relationships, types, and amount of finances that fund the public health system in America. This research was undertaken to build on the sparse knowledge of public health finance by examining the value of performance measurement systems to financial analysis. A correlational study was conducted to examine the associations between public health system performance of the 10 essential public health services and funding patterns of 50 local health departments in a large state. The specific objectives were to investigate if different levels and types of revenues, expenditures, and other demographic variables in a jurisdiction are correlated to performance. Pearson correlation analysis did not conclusively show strong associations; however, statistically significant positive associations primarily between higher levels of performance and jurisdiction taxes per capita were found.     

Predictors of success in macular hole surgery with emphasis on the internal limiting membrane (ILM) and ILM peeling.

BACKGROUND AND OBJECTIVE: To study the predictors of success in macular hole surgery. PATIENTS AND METHODS: Twenty-two eyes of 21 patients underwent macular hole surgery. The hole closure rate and the visual improvement were studied based on the preoperative visual acuity, stage and duration of the macular hole, the type of intravitreal tamponade used, and internal limiting membrane peeling. The internal limiting membrane was peeled only when it was clinically prominent. RESULTS: Macular holes were closed in 19 of the 22 eyes and visual improvement of 2 lines or more was achieved in 17 eyes. Preoperative visual acuity, duration of the macular hole, type of intraocular tamponade used, and internal limiting membrane peeling did not affect the outcome. A final visual acuity of 20/70 or better was more common after surgery for stage 2 holes (P = .019). CONCLUSION: The best predictor of outcome was the stage of the hole, with best results obtained in stage 2 holes.