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Biomedical subjects

N Schmidt

Publications and source records attributed to N Schmidt.

At least 55 records · Page 3Linked to original sources
PubMed1993

Diagnosis and management of stage IE and stage IIE gastric lymphomas.

We performed a retrospective study involving 56 patients with stage IE or stage IIE gastric lymphomas treated between January 1980 and January 1990. Endoscopy had a sensitivity of 98% compared with 83% for radiographic contrast studies. The data were analyzed with respect to 10 prognostic factors. Age greater than 65 years and an elevated lactate dehydrogenase level were associated with a significantly lower 5-year survival rate (each p = 0.001). Those patients having had gastric resection with grossly negative margins demonstrated improved survival compared with those patients who did not have complete resection (67% versus 29%). The use or omission of radiotherapy had no effect on survivorship (51% versus 55%). Neither tumor size, stage, sex, site of extragastric involvement, time from onset of symptoms to diagnosis, nor microscopic resection margins influenced survival. We conclude that endoscopy with biopsy is the diagnostic procedure of choice for gastric lymphoma. Gastric resection still plays an important role in the management of stage IE and stage IIE gastric lymphomas, whereas chemotherapy remains the mainstay of therapy. The role of radiotherapy remains undefined.

Aged↗
PubMed1993

Rapid determination of methadone in plasma, cerebrospinal fluid, and urine by gas chromatography and its application to routine drug monitoring.

Determination of methadone (MET) in biological fluids can serve to adjust dosages in patients suffering from cancer pain or participating in methadone maintenance programs. We developed a gas chromatographic assay using nitrogen-phosphorus detection. The method involves a single-step extraction from alkalized plasma, cerebrospinal fluid, or urine into n-hexane/isoamyl-alcohol (99/1, v/v). Dextropropoxyphene was used as internal standard. Separation was achieved with a silica SE-52-CB column (13 m x 0.25-mm I.D.). The method was validated for the determination of MET in plasma, urine, and cerebrospinal fluid with a quantification limit of 0.5 ng/mL. The coefficients of variation for within-day and between-day precision were within 10.2 and 14.1%, respectively. Approximately 100 samples can be analyzed by one person in the course of a working day, making the method applicable to routine drug monitoring. The method was demonstrated to be sensitive and accurate for pharmacokinetic studies in plasma, urine, or cerebrospinal fluid.

Chromatography, Gas↗
PubMed1993

Birth trauma: its effect on the urine continence mechanisms.

Birth trauma is the most important etiological factor in the genesis of stress urinary incontinence in women (SUI). There is a high incidence of SUI during pregnancy, and after delivery SUI persists in a small percentage of women (2-3%). Almost all studies on perineal muscle function reveal decreasing intravaginal pressures in the days after delivery which rarely return to predelivery levels. A few urodynamics studies have demonstrated reduced urethral closure pressures and functional length after vaginal delivery, but the importance of such findings in the genesis of SUI is controversial. Better consensus has been found when pelvic floor neurophysiology was carried out: there is electromyographic evidence of a denervation-reinnervation pattern in the striated urethral sphincter muscle and occasionally prolonged pudendal conduction times when the pudendal nerves are directly stimulated. Histomorphologic studies of the pelvic floor have demonstrated that, in some women, abnormal collagen types are responsible for vaginal prolapse and accompanying SUI. Finally, the great importance of perineal reeducation by electromyostimulation and biofeedback in patients with traumatic pelvic floor pathology may be emphasized, but the importance of its role in the prevention of late SUI development remains to be established by more prospective studies.

Adult↗
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.

Explore the source record for details and available documents.

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↗