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Biomedical subjects

N Schmidt

Publications and source records attributed to N Schmidt.

At least 19 recordsLinked to original sources
PubMed1992

Stereoselective determination of the enantiomers of methadone in plasma using high-performance liquid chromatography.

An enantioselective high-performance liquid chromatographic assay for the quantification of methadone in human and beagle plasma is described. The procedure involves extraction of methadone from alkalized plasma into hexane-isoamyl alcohol (99:1, v/v). Stereoselective separation was achieved with a silica column with covalently bound alpha 1-acid glycoprotein (Chiral-AGP) without any derivatization procedure. The detection wavelength was set at 215 nm. Using an internal standard provided reliable control of the extraction procedure as well as quantification of the enantiomers of methadone. The limit of quantification was found to be 2.5 ng/ml. The method was demonstrated to be sufficiently sensitive for stereoselective pharmacokinetic studies of methadone.

Adult↗
PubMed1992

Subjective and objective effects of intravaginal electrical myostimulation and biofeedback in patients with genuine stress urinary incontinence.

A group of 36 patients (18 premenopausal and 18 postmenopausal), all suffering from genuine stress urinary incontinence, underwent conservative treatment with 6 sessions of intravaginal electromyostimulation followed by 6 sessions of biofeedback; 89% of patients reported an improvement, 5.5% considered themselves cured and 5.5% reported no change. Intravaginal pressure measured before and after therapy increased by an average of 11 cm H2O in premenopausal patients and 17 cm H2O in the postmenopausal group. Intravaginal pressure increased in all patients and, according to maximal urethral closure pressure, this increasing intravaginal pressure was observed even in patients with low pressure urethras. The urodynamic factors studied were functional length, maximum urethral closing pressure and pressure transmission, together with urethral surface at rest and during stress, and residual surface. No significant changes were noted before and after treatment. The excellent subjective results contrast with the absence of improvement in these values.

Adult↗
PubMed1992

Pancreatic duct obstruction treated with percutaneous antegrade insertion of a metal stent: report of two cases.

Expanding metal stents were used to treat symptomatic pancreatic duct obstruction in two patients with chronic pancreatitis. Both patients initially underwent percutaneous external pancreatic duct drainage and then had metal stents inserted for internal drainage. Both patients remained asymptomatic, and the stents were patent during short-term follow-up periods of 6 and 9 months, respectively. Percutaneous insertion of metal stents, which can be performed to treat pancreatic duct obstruction after a trial of external drainage has been shown to relieve the patient's symptoms, should be considered as an alternative to endoscopic stent placement or surgical drainage.

Aged↗
PubMed1991

Efficient management of adrenal tumors.

A retrospective analysis was carried out on 121 patients with primary adrenal tumors operated on at 2 Vancouver hospitals between the years 1970 and 1990. The purpose of the study was to identify discriminating factors between the various diagnoses in order to minimize both the time and the cost of the investigative process. There were 57 cortical adenomas, 35 pheochromocytomas, 15 carcinomas, 8 cases of cortical hyperplasia, and 6 miscellaneous tumors. The mean time from the onset of symptoms to diagnosis of those patients presenting with an identifiable syndrome was 48.3 months. Those with a hypertensive syndrome presented significantly later than those with Cushing's syndrome (57.7 months versus 22.8 months, p less than 0.01). There was a significant delay in diagnosis in those patients with hypertension on the basis of an aldosteronoma as compared with those with hypertension secondary to a pheochromocytoma (75.4 months versus 36.1 months, p = 0.02). Cortical carcinomas were significantly larger than benign cortical tumors (12.7 cm versus 5.5 cm). No malignant neoplasm measured less than 5 cm in diameter. Diagnostic sensitivity for intravenous pyelogram (IVP) was 59%, for ultrasound 71%, for venography 50%, for meta-iodobenzylguanidine (MIGB) (pheochromocytoma only) 80%, and for angiography 70%. However, for those patients with adrenal carcinomas, angiography was positive in 100% of cases. Computed tomography (CT) was the most sensitive localizing investigation with a sensitivity of 98%. While other localizing techniques were less sensitive than CT, they may still play a useful role in selected situations. Factors causing delay in diagnosis and the role of the various imaging modalities are discussed.

Adenoma↗
PubMed1991

Effect of occluding the urethra while recording urethral stress profile.

The correlation between clinical and tonometric incontinence is frequently poor, with urethral profile results that do not correspond to clinical reality. Among potential causal factors, we have attempted to determine the importance of the absorption of kinetic energy from the mass of urine driven against the urethral captor (the hydraulic ram effect). Twenty patients (average age 50 +/- 10 years, para 2) suffering from genuine stress urinary incontinence, underwent urodynamic investigation with a constant air-flow pneumatic catheter equipped with two captors separated by an inflatable cuff located just above the urethral captor to block the inrush of urine into the urethra. After cystometric examination had excluded an unstable bladder, two urethral profiles were registered successively, first with cuff deflated, and then with cuff inflated. The values for urethral functional length (FL) and transmission factor (TF) show no significant changes. The values for the maximal urethral closing pressure (MUCP) were significantly lower in the second profile (cuff inflated) in 18 of 20 cases (average decrease 7 cm H2O), which corresponds to 14 percent of the average MUCP measured during the first profile (cuff deflated). The depression quotient increased from an average 0.80 to 1.05 from first to second profile. This study allows quantification of the urethral "hydraulic ram effect" which modifies determination of the MUCP during registration of urinary stress profile.

Female↗
PubMed1990

Biliary colic.

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Cholecystectomy↗
PubMed1990

[Recurrent hematemesis caused by paraprosthetic aorto-digestive fistula].

The authors report the observation of a paraprosthetic fistula revealed by three episodes of digestive haemorrhage, illustrating the diagnostic and therapeutic difficulties brought about by the erosion of the duodenum by a sub-renal aortic prosthesis. A review of the literature confirms the rarity and the gravity of this pathology, and underlines the per-operative preventive measures.

Aortic Aneurysm↗
PubMed1989

Toxicity of metallic ions and oxides to rabbit alveolar macrophages.

The effects of soluble compounds and oxides of As, Cd, Cu, Hg, Ni, Pb, Sb, Sn, V, and Zn on oxidative metabolism and membrane integrity of rabbit alveolar macrophages were studied by 24-hr in vitro exposure. Oxidative metabolism induced by phagocytosis of opsonized zymosan was measured by H2O2 and O2- release and by chemiluminescence in the presence of luminol. Membrane integrity was estimated by extracellular LDH activity. Metallic ions and oxides inhibited the release of active oxygen species. Cd(II), As(III), and V(V) were the most toxic elements as measured by all investigated parameters. Cu(II) decreased O2- release and chemiluminescence effectively but H2O2 release and membrane integrity less. Chemiluminescence was decreased strongly by Hg(II) while O2- and H2O2 release were depressed moderately. Zn(II) and Sb(III) compounds caused medium toxicity and the tested Sn, Ni, and Pb compounds showed only faint toxic effects.

Animals↗
PubMed1989

Perceptions of South Dakota adults concerning selected adolescent health problems.

A telephone survey was conducted of a random sample of 1,015 South Dakota households to assess adults' perceptions of whether alcohol and drug abuse, teen pregnancy, and suicide attempts are problems in their community, and across the state, among seventh through twelfth grade adolescents. A majority of the respondents indicated that alcohol and drug abuse, and teen pregnancy are a problem for adolescents in their community and across the state. Regarding suicide attempts among adolescents, over a quarter of the respondents indicated that they are a problem in their community, and one half of the respondents indicated that they are a problem across the state. Alcohol and drug abuse, teen pregnancy, and suicide attempts are more likely to be reported as being a problem across the state than in the local community. Respondents overwhelmingly agreed that health education programs in schools can help prevent alcohol and drug abuse, teen pregnancy, and suicide attempts among seventh through twelfth graders.

Adolescent↗
PubMed1989

[Tissue effects of extracorporeal lithotripsy on a model of experimental biliary calculi in dogs].

Extracorporeal shock waves represent a new method to treat gallstones. This study was designed to evaluate: 1) the effectiveness of a recently available lithotripter (EDAP LT 01) for gallstone fragmentation; 2) adverse tissue reactions after treatment; 3) the optimum conditions for use of this apparatus in man. A human cholesterol stone was surgically implanted into the gallbladder of ten 20-25 kg mongrel dogs. One dog was used as a control. The other nine animals were divided into three groups (A, B and C). Two 60 min sessions of lithotripsy were carried out twice a week. Sonographic and CT examinations were performed 9 and 16 days after operation. The animals were killed 21 days after operation. Satisfactory fragmentation was obtained in 4 of the 9 animals, and in 2 dogs no stone fragments were detected. Fragments were found in the common bile duct in 5 dogs. In 2 animals a pathologic aspect of the papilla of Vater was observed. Marked hematoma was observed in the animals treated at 5 and 10 pulses/sec. In 5 cases, hematoma was observed in the gallbladder and in one case the gallbladder was ruptured. Hematoma was also noted in the hepatic vascular bed in 3 animals. Except for microscopic hemorrhagic lesions observed at the base of the right lung, no lesions were detected in any other organ. Shock waves produced by the EDAP LT 01 are effective for fragmentation of gallstones. However, in view of the tissue reactions observed at the higher pulse rates, the pulse rate should not exceed 2.5 pulses/s for use in man.

Animals↗
PubMed1989

An adrenalin rush.

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Adrenal Gland Neoplasms↗