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Biomedical subjects

M Weiss

Publications and source records attributed to M Weiss.

At least 865 records · Page 48Linked to original sources

Pallidal administrations of gabazine and 5-AVA affect pressure-induced behavioral disorders in rats.

The aim of this work was to study the role of pallidal GABAa and GABAb neurotransmission in the behavioral disorders induced by pressure. The effects of GABAb antagonist 5-aminovalleric acid (5-AVA) or GABAa antagonist gabazine administrations in the globus pallidus (GP) on locomotor and motor hyperactivity (LMA) and myoclonia expressions in the model of the rat submitted to 8 MPa of helium-oxygen breathing mixture were analyzed. The administration of GABAa antagonist gabazine enhances the occurrence of the epileptic seizures, slightly increases LMA but decreases myoclonia. In contrast, the administration of GABAb antagonist 5-AVA decreases both LMA and myoclonia during the compression and the beginning of the holding time at 8 MPa. These data indicate that some behavioral disorders induced by pressure are in relation with GABAergic neurotransmission and establish clearly that GABAa and GABAb receptor mediations have distinct functions in the GP of the rat.

Amino Acids, Neutral↗

QTc interval and scintigraphically assessed myocardial perfusion in newly diagnosed and long-term type 1 diabetes mellitus.

In diabetes mellitus, heart rate corrected QT interval (QTc) has been suggested to be related to ischemic heart disease and increased risk of sudden cardiac death. The aim of the study was to analyze the length of QTc interval with regard to global and regional myocardial perfusion in type 1 diabetic patients. Myocardial perfusion was investigated in 20 newly diagnosed and 40 long-term type 1 diabetic patients without clinical evidence for coronary artery disease by means of Tc-99-methoxyisobutylisonitrile (Tc-99m-MIBI)-scintigraphy (myocardial uptake (MU) score: 1-6). Five consecutive RR and QT intervals of resting electrocardiogram (ECG) tracing were measured and corrected for the previous cycle length. ECG-based cardiac autonomic neuropathy (CAN) was assessed with five cardiac reflex tests. Length of QTc interval was 423+/-29 ms in newly diagnosed and 433+/-26 ms in long-term type 1 diabetic patients. Nine (45%) newly diagnosed and 18 (45%) long-term diabetic patients demonstrated a prolonged QTc interval (>440 ms). Both newly diagnosed and long-term diabetic patients did not display significant global or regional myocardial perfusion defects (mean MU scores<3). In newly diagnosed diabetic patients, the length of QTc interval was related to global, posterior and septal Tc-99m-MIBI uptake (p<0.05, respectively). In long-term diabetic patients, the length of QTc interval was associated with apical Tc-99m-MIBI uptake (p<0.05). Two (10%) newly diagnosed and 19 (48%) long-term type 1 diabetic patients demonstrated ECG-based CAN. In long-term type 1 diabetic patients, global myocardial Tc-99m-MIBI uptake did not differ significantly between patients with and without CAN. QTc interval was not significantly different between diabetic patients with and without ECG-based CAN (433+/-19 ms vs. 428+/-17 ms). Long-term diabetic patients, of whom 10 (25%) patients had microalbuminuria and seven (18%) patients had macroalbuminuria, demonstrated an association between QTc interval and albuminuria (p<0.05). The results somewhat suggest an association between QTc interval and vascular factors in type 1 diabetes mellitus. Future investigations are required to analyze the role of QTc interval in the pathogenesis of abnormalities of myocardial perfusion.

Adult↗

Three-year follow-up on scintigraphically assessed cardiac sympathetic denervation in patients with long-term insulin-dependent (type I) diabetes mellitus.

Scintigraphy using I-123-metaiodobenzylguanidine (I-123-MIBG) and Tc-99m-methoxyisobutylisonitrile (Tc-99m-MIBI) allows assessment of the cardiac sympathetic innervation and the myocardial perfusion. To investigate the natural history of cardiac sympathetic denervation in long-term diabetic patients without myocardial perfusion defects, global and regional I-123-MIBG and Tc-99m-MIBI uptake was determined (score 1-6; 1 = normal uptake, 6 = no uptake) in 22 patients with insulin-dependent (type I) diabetes mellitus (IDDM) at 3-year follow-up. All patients were treated with intensive insulin therapy and HbA1c was 8.0% +/- 1.0% at entry compared with 7.9% +/- 1.1% at follow-up. Cardiac sympathetic denervation (I-123-MIBG uptake score > 2), initially observed in 18 patients, was detectable in 21 patients at follow-up. The global myocardial I-123-MIBG uptake score deteriorated in eight patients, remained unchanged in 11 and improved in three patients. The changes in mean global I-123-MIBG uptake score (3.5 +/- 1.0 versus 3.8 +/- 0.8) were not significant. Reduction of the anterior, lateral, posterior, septal, and apical I-123-MIBG uptake did not progress significantly during follow-up. The mean uptake score of the posterior myocardial region (4.7 +/- 0.8) was smaller than the uptake score of the anterior (3.0 +/- 1.1, p = 0.001), lateral (3.2 +/- 0.9, p < 0.001) and septal (4.1 +/- 1.1, p < 0.05) myocardial regions. At follow-up, moderate myocardial perfusion defects (global Tc-99m-MIBI uptake score = 3) were detectable in four patients. Our study demonstrates that scintigraphically assessed cardiac sympathetic denervation does neither significantly regress nor progress on the average in a group of long-term IDDM patients during a 3-year follow-up. Thus, it is concluded that cardiac sympathetic abnormalities are a persistent, yet frequent phenomenon in long-term IDDM patients.

3-Iodobenzylguanidine↗

[Tumoral calcinosis of the ischium].

The authors report on a case of tumoral calcinosis of the ischium in a 63 year old female. A general review of the literature on pathogenesis, histological characteristics and the way of treatment is given and the prognosis of tumoral calcinosis pointed out.

Bone Neoplasms↗

Vancomycin-resistant-enterococci--colonization of 24 patients on a pediatric oncology unit.

BACKGROUND: Colonization with multidrug-resistant vancomycin-resistant-enterococci (VRE) could become a serious problem, since there is no proven therapy in case of an infection or in case of transfer of glycopeptid-resistance to other organisms. PATIENTS: Description of 24 from 48 pediatric oncology patients with VRE-colonization. METHODS: Stool samples were taken from all patients of our pediatric oncology unit from March 1996 until June 1997. Barrier isolation was introduced in May 1996, a prudent use of glycopeptid antibiotica in July 1996. RESULTS: 193 stool sample examinations demonstrated that 24 (50%) of the 48 patients were colonized with VRE. 11 (46%) of these 24 patients were VRE-carriers at the time of their first examination; 9 (37%) patients acquired VRE during their therapy and 4 (17%) patients had come from other hospitals and already were VRE-positive when they entered our unit. In March 1997, one year after the outbreak only four patients still were VRE-positive, in June 1997 all of them were VRE-negative. The average time of colonization was 12.5 weeks. 17 (70%) of the 24 colonized patients had received glycopeptide antibiotics, 16 of them within two months before the appearance of VRE in their stool. Five colonized patients died, four of them because of their oncological illness, one because of a sepsis without proof of VRE in his blood. In the end none of our patients suffered from a VRE-infection, and besides that, the transfer of glycopeptid-resistance to other organisms was not observed. CONCLUSION: With barrier isolation and a very restrictive use of glycopeptid-antibiotica, colonization can be decreased and even stopped. Inspite of the high number of colonized patients no VRE-infectious disease occurred.

Adolescent↗

[Albinism, thrombopathy, ceroid storage disease--Hermansky-Pudlak syndrome. Overview and description with immunodeficiency].

The Hermansky-Pudlak Syndrome (HPS) is a rare autosomal recessively inherited triad of oculocutaneous albinism hemorrhagic diathesis and accumulation of ceroid in tissues. This article comprising the published reports of 232 patients is extended by the personal observation of a 7-year-old boy with HPS and immune deficiency due to a reduced activity of "natural killer" cells. In most cases the syndrome belongs to a form of tyrosinase-positive albinism with great clinical variability. The prolonged bleeding time is due to the lack of storage organelles (dense bodies) in thrombocytes. The most frequent complication of ceroid storage is fibrotic, restrictive lung disease. So far no curative therapy exists; the nature of the defect is still unknown.

Albinism, Oculocutaneous↗

[Dyskeratosis congenita. Genetic hematologic-immunologic systemic disease with pancytopenia].

Dyskeratosis congenita (DC) is a rare, predominantly X-linked multisystemic disorder. It shows a wide spectrum of clinical manifestations and typically presents with dermatological symptoms within the first decade. This review of the literature points out the importance of haematological and immunological changes defining course and prognosis of disease. Pancytopenia, humoral and cellular disorders of immune function may lead to severe infections, which present the main cause of death. The pathogenesis of DC is still unclear, no causative therapy is available. Recent reports suggest a beneficial effect of haemato-poietic growth factors (G-CSF, GM-CSF) in patients with DC and neutropenia.

Child↗

Gastrointestinal anastomosis with histoacryl glue in rats.

Technical difficulties in creating gastrointestinal anastomosis in infants and young children, because of the small lumen, are well known and may be complicated by a narrow passage, anastomotic obstruction, gastric stasis, recurrent vomiting, and failure to gain weight. The search for alternative easier technique was the basis for this study. The primary aim was to evaluate the safety of anastomosis between the stomach and a loop of the jejunum performed by using the tissue adhesive Histoacryl glue in comparison with the same anastomosis performed conventionally with absorbable sutures. We compared the results of gastrojejunal anastomosis in rats using either Histoacryl (n-butyl cyanoacrylate) glue or continuous, absorbable sutures. Sixty-four Sprague-Dawley rats were divided into 4 groups of 16 rats each. Gastroenterostomy was performed with either type of anastomosis with and without truncal vagotomy. The criteria ofgastroenterostomy investigated included anastomotic leakage, stricture formation, adhesion formation, and histological examination. The pH of gastric secretion was measured with intact gastric innervation and after vagotmy in all rats. The time to complete each type of anastomosis was measured in minutes. Anastomotic stricture, leak, peritonitis, and death happened in three rats in each group with intact vagal innervation, in two rats after vagotomy and anastomosis with Histoacryl, and in one rat after vagotomy and anastomosis with sutures. The results showed no statistically significant differences between the various groups, except the shorter time for performing the glued anastomosis (5-7 min) compared to the conventional anastomosis (16-21 min). In conclusion, gastroenterostomy with Histoacryl in rats appears to be as safe as conventional suture anastomosis, saves operating time, and is not affected by gastric acidity.

Adhesives↗

Clinical practice improvement: management of the patient with chronic asthma.

Clinical practice improvement (CPI) includes research on practice patterns, access, utilization of resources, and patient perceptions of outcomes; development of practice guidelines; and education of both patients and providers. Using the CPI format, a team of healthcare professionals selected the management of the asthma patient as a project. The team's goals were to evaluate current practice patterns, review and recommend practice guidelines, recommend indicators to monitor patient outcomes and changes in practice patterns, and provide recommendations for implementing educational activities. A survey mailed to primary care physicians and selected specialists (allergists and pulmonologists) was used to determine present methods of managing asthma. A patient outcomes survey tool was piloted as part of the CPI process. The pilot indicated that this tool was appropriate for use in physician offices for both longitudinal and aggregate analysis of asthma patient outcomes. Patient and provider educational materials were developed and disseminated to providers.

Adolescent↗

Dramaturgical study of meetings between general practitioners and representatives of pharmaceutical companies; Commentary: dramaturgical model gives valuable insight.

OBJECTIVES: To examine the interaction between general practitioners and pharmaceutical company representatives. DESIGN: Qualitative study of 13 consecutive meetings between general practitioner and pharmaceutical representatives. A dramaturgical model was used to inform analysis of the transcribed verbal interactions. SETTING: Practice in south west England. PARTICIPANTS: 13 pharmaceutical company representatives and one general practitioner. RESULTS: The encounters were acted out in six scenes. Scene 1 was initiated by the pharmaceutical representative, who acknowledged the relative status of the two players. Scene 2 provided the opportunity for the representative to check the general practitioner's knowledge about the product. Scene 3 was used to propose clinical and cost benefits associated with the product. During scene 4, the general practitioner took centre stage and challenged aspects of this information. Scene 5 involved a recovery strategy as the representative fought to regain equilibrium. In the final scene, the representative tried to ensure future contacts. CONCLUSION: Encounters between general practitioners and pharmaceutical representatives follow a consistent format that is implicitly understood by each player. It is naive to suppose that pharmaceutical representatives are passive resources for drug information. General practitioners might benefit from someone who can provide unbiased information about prescribing in a manner that is supportive and sympathetic to the demands of practice. What is already known on this topic Pharmaceutical representatives influence physicians' prescribing in ways that are often unacknowledged by the physicians themselves Meetings with pharmaceutical representatives are associated with increased prescribing costs and less rational prescribing What this study adds Meetings between pharmaceutical representatives and general practitioners follow a consistent format that is implicitly understood by each player General practitioners may cooperate because representatives make them feel valued

Drug Industry↗

Pressor responses of rat isolated tail arteries to contractile stimulation after methylene blue treatment: effect of adventitial versus intimal entry.

To test the hypothesis that drug entry site (intimal vs. adventitial surface) may be an important determinant of methylene blue (MB) action on vascular reactivity to contractile stimulation, we used preparations of rat isolated tail arteries perfused at constant flow (2 ml/min). Perfusion pressure changes reflecting vascular responses to cumulative addition of phenylephrine (PE) or dopamine (DOP) were recorded before and after MB addition (2.5 x 10(-4) M final concentration) at the intimal or adventitial surface. Intraluminal addition of MB resulted in strong potentiation of subsequent responses to intimal contractile stimulation using PE or DOP. This effect was not observed when MB was added at the adventitial surface. These results suggest that drug entry site is an important determinant of MB action on vascular responsiveness in the rat tail artery and might account for the divergent results in the literature on the vascular action of MB.

Animals↗

An evaluation of postoperative follow-up tests in colon cancer patients treated for cure.

BACKGROUND: Currently patients with colon cancer who are potentially cured by surgery are followed periodically with physical examinations, blood tests and imaging studies to detect tumor recurrence early, on the presumption that intervention can effect outcome. There is little information to indicate whether frequent visits to the doctor's office or frequent testing improves survival or quality of life. METHODS: Ninety-eight patients with resected stage B2, B3 or C (modified Astler-Coller) colon cancer who developed recurrent disease while enrolled in prospective adjuvant trials at Mayo Clinic sponsored by the North Central Cancer Treatment Group were studied to evaluate the utility of follow-up tests to detect the first recurrence of colon cancer and the outcome following various interventions for these recurrences. These patients had a history, physical examination, complete blood count, chemistry panel and chest x-ray approximately every 3-4 months in the 1st year and then every 6-12 months thereafter for a total of 5 years. Bowel evaluation was done at 6 months, 12 months and annually thereafter. In addition, a minority of patients had carcinoembryonic antigen (CEA) testing, and radioisotope liver scans at various intervals. RESULTS: Symptoms signaled the diagnosis of recurrent disease in 55 patients, physical examination in 4 patients, and abnormalities in chest x-ray in 18 patients. An elevated CEA was the initial abnormal test in 5 patients, abnormal liver scans in 5 patients, elevated liver function tests in 6 patients and laparotomy for other reasons in 2 patients. Hemoglobin, barium enema, and fecal blood testing were useful in 1 patient each. Thirty-one percent of recurrences were diagnosed between scheduled visits. In our series, histories, physical examinations, and chest x-rays led to the detection of 79% of the recurrences while liver function tests, liver scans and CEAs led to the detection of 16% of recurrences. Sixteen patients underwent resection for cure for their first recurrence; the diagnosis of recurrence was signaled by symptoms in 6 patients, chest x-ray in 6 patients and abnormal liver function tests, CEA, hemoglobin, and laparotomy for colostomy closure in 1 patient each. CONCLUSIONS: The majority of tumor recurrences were detected by symptoms, physical examinations and chest x-rays. Testing for asymptomatic tumor recurrences during the 1st follow-up year is likely to be much less fruitful for detecting resectable recurrences than testing patients in the 2nd through 4th follow-up years. Patients who had a disease recurrence in the 1st postoperative year were less likely to be candidates for curative intent surgery. Lower tumor grade at initial diagnosis correlated both with likelihood of undergoing secondary surgical resection and the chance of doing well following this. These data may be helpful for defining more appropriate follow-up test for detection of tumor recurrence in patients with resected colon cancer.

Adult↗

Postprandial hyperinsulinemia in patients with mild essential hypertension.

Glucose tolerance tests and diurnal profiles of glucose, insulin, free fatty acids, serum triglycerides, total and high-density lipoprotein cholesterol levels were performed in 8 male patients with mild essential hypertension as well as in 20 normotensive subjects. Although glucose tolerance and postprandial glucose levels appeared equal in both groups, the insulin response after a glucose load and after each meal was significantly increased in hypertensive subjects as compared with the controls (p less than 0.01). The levels of free fatty acids were higher in the postabsorptive phase of patients with hypertension in comparison to normotensive subjects, but decreased markedly when plasma insulin levels rose after meals. In both subject groups serum triglyceride levels showed the typical postprandial increase. Total and high-density lipoprotein cholesterol levels showed neither diurnal variations nor differences between hypertensive subjects and normotensive controls. Postprandial hyperinsulinemia in patients with mild essential hypertension possibly may provoke lipid accumulation in the arterial wall and therefore may be a relevant risk factor for atherosclerosis in these subjects.

Adult↗

Glutamine supplementation in low-birth-weight infants: mechanisms of action.

Very low-birth-weight infants have minimal endogenous nutritional reserves and are at high risk for stresses that induce further breakdown of these diminished reserves. They frequently receive very little glutamine because enteral feedings are often delayed and glutamine is not included in parenteral nutrition. Here we describe studies of glutamine supplementation in very low-birth-weight infants and discuss potential mechanisms for the beneficial effects.

Cross Infection↗

Emergence of highly antibiotic-resistant Pseudomonas aeruginosa in relation to duration of empirical antipseudomonal antibiotic treatment.

OBJECTIVE: This study examines antibiotic resistance in Pseudomonas aeruginosa in hospitalized patients in relation to prior empirical antibiotic therapy. DESIGN: Two retrospective case analyses comparing patients who manifested P aeruginosa with differing patterns of antibiotic resistance. SETTING AND PARTICIPANTS: Patients acquiring P aeruginosa in a community hospital. MEASURES: Patients were compared on duration of hospitalization and days and doses of antibiotics prior to recovery of P aeruginosa. Patients were grouped, based on susceptibility patterns of their P aeruginosa isolates classified as follows: (1) fully susceptible (susceptible to all classes of antipseudomonal antibiotics [SPA]), (2) multidrug-resistant (resistant to two classes of antipseudomonal antibiotics [MDRPA]), or (3) highly drug-resistant (resistant to > or = 6 classes of antipseudomonal antibiotics [HRPA]). To control for duration of hospitalization, antibiotic treatments of HRPA and SPA patients were compared during the first 21 days of care. RESULTS: Prior to recovery of HRPA, six HRPA patients received greater amounts of antibiotics, both antipseudomonal and non-antipseudomonal, than did six SPA patients prior to recovery of SPA. For 14 patients with hospital-acquired SPA who later manifested MDRPA, duration and dosage of antipseudomonal antibiotics, but not all antibiotics, were significantly higher for the SPA-to-MDRPA interval than for the preceding admission-to-SPA interval. The median duration of antipseudomonal antibiotic treatment prior to the recovery of P aeruginosa was 0 days for SPA, 11 days for MDRPA, and 24 days for HRPA. CONCLUSION: Duration of empirical antipseudomonal antibiotic treatment influences selection of resistant strains of P aeruginosa; the longer the duration, the broader the pattern of resistance.

Adult↗