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Biomedical subjects

M Sheehan

Publications and source records attributed to M Sheehan.

12 recordsLinked to original sources
PubMed1992

Permanent iodine-125 implant and external beam radiation therapy for the treatment of malignant brain tumors.

Survival data of 114 patients treated for malignant brain tumors with 125I interstitial radiation therapy at Henry Ford Hospital, Detroit, Mich. (1986-1990), are presented. The first 64 patients were treated with temporary 125I implants with a total prescribed dose of 60 Gy at a dose rate of 40 cGy/h. In order to reduce the risk of injury to the surrounding normal tissue associated with high-dose brachytherapy, a new approach was initiated using permanent implants with a lower dose rate; 50 patients were treated after surgical resection with permanent implantation of 125I seeds at a lower dose rate of 4-7 cGy/h, with a total dose of 10,000-12,000 cGy, and concurrent external radiation therapy of 5,000 cGy. The rationale of this protocol was to increase the effectiveness of the low-dose-rate implant by a concurrent 'daily' boost of external radiation, thus inhibiting the proliferation of tumor cells during the protracted low-dose radiation treatment. Survival was compared between groups with permanent and temporary implants in terms of effectiveness in tumor control as well as impact on clinical condition. Low-dose-rate implant with concurrent external radiation therapy seems to offer the best chance for long-term survival without deterioration in the clinical condition.

Adult↗
PubMed1979

Predictive values of various liver function tests with respect to the diagnosis of liver disease.

A prospective study of 181 patients suspected of having liver disease was carried out to determine the relative efficiencies of serum bilirubin (total and direct), alkaline phosphatase (AP), gamma glutamyl transferase (GGT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) with respect to diagnosis. Liver biopsies, liver scans, abdominal ultrasound, and clinical parameters were also tabulated and used independently to evaluate the patient's hepatic status and to determine the final diagnoses in each case. From the results of these tests for the 60 patients who were diagnosed as having liver disease, and the 87 patients who were felt to be free of liver disease, predictive values of the above tests were established. Data from this study suggests that while direct bilirubin is the most specific test, GGT is the most sensitive and has the fewest false negatives in the diagnosis of liver disease.

Alanine Transaminase↗
PubMed1978

Meconium aspiration syndrome. Neonatal and follow-up study.

One year's experience with MAS in a neonatal intensive-care unit is analyzed with follow-up information. Seventeen patients or 3.7% of all admissions had MAS. Four patients (23.5%) died of acute respiratory failure. Two patients with MAS and persistence of the fetal circulation required cardiac catheterization to exclude cyanotic congenital heart disease. No survivors had persistent chronic lung disease. However, two of three patients with MAS and seizures had significant psychomotor retardation at follow-up examination.

Amniotic Fluid↗
PubMed1977

Combined thin-layer and gas-liquid chromatographic identification of tricyclic antidepressants in urine.

A combined thin-layer and gas-liquid chromatographic (TLC-GLC) procedure for determination of tricyclic antidepressant drugs in urine is described. GLC on 1.5% OV-17 was utilized to analyzed basic urine extracts directly for the tricyclics and to confirm the identity of spots extracted from thin-layer chromatograms, and TLC was used to confirm the results of these GLC screens. Lower limits of sensitivity for the thin-layer spot extraction procedure were found to range from 2 mug/ml for amitriptyline and imipramine to 10 mug/ml for desipramine and nortriptyline. Turn-around-times for the GLC tricyclic screens were usually less than 1 h. The finding that nortriptyline and desipramine were chemically altered under various extraction conditions was used as a means of confirming the identity of these drugs, and the identity of these chemically altered derivatives was discussed with reference to their low resolution mass spectra.

Adolescent↗
PubMed1977

Gas-chromatographic/mass-spectrometric determination of theophylline in whole blood.

We describe a combined gas-chromatographic mass-spectrometric method for determination of theophylline in whole blood. With use of a probability-based matching approach, the extensive gas-chromatographic interference did not affect mass-spectrometric quantitation of theophylline. Concentrations expected and found were linearly related from 1 to 60 mg/liter; the run-to-run coefficient of variation was less than 8%, within-run less than 6%. Some other xan-thines and drugs frequently co-administered with theophylline did not affect results. Only 0.2 ml of blood is required, which makes the procedure useful for monitoring theophylline in newborns and pediatric populations.

Chromatography, Gas↗
PubMed1976

Rapid gas chromatographic determination of underivatized theophylline in whole blood.

A rapid gas chromatographic method for the determination of underivatized theophylline in whole blood is described. Theophylline is extracted from acidified blood and chromatographed directly using cyheptamide as an internal standard. Concentrations of the drug down to 2 mug/ml in blood could be determined with recoveries ranging from 90 to 110%.

Chemical Phenomena↗
PubMed1975

GLC determination of underivatized carbamazepine in whole blood.

This report describes a rapid GLC assay for carbamazepine in blood. Carbamazepine is chromatographed directly using phenyl methyl silicone gum as the stationary phase. The calibration curve is linear up to 50 mug/ml, with a lower limit of sensitivity of 1 mug/ml. Other anticonvulsants may be measured simultaneously, and the procedure works equally well with plasma or blood.

Carbamazepine↗
PubMedDate not supplied

Mortality among drug addicts in Greater London.

During January 1970 to December 1974, 134 deaths in people aged 10-50 years investigated by coroners in Greater London were recorded as being due to drug addiction. Over three-quarters of the addicts were under 30, and 105 (78%) were male; 55 (41%) were unknown to the Home Office. Barbiturate overdose accounted for over half of the deaths, though two-thirds of these were in people registered as addicts to notifiable drugs. Since the Home Office index is concerned with addiction to one class of drugs only, it fails to reflect accurately the prevalence of all serious forms of addiction. Owing to the continuous change in drug-taking behaviour, however, probably no one method of assessment can provide a complete picture, and thus complementary research methods are essential.

Adolescent↗