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Biomedical subjects

S Shah

Publications and source records attributed to S Shah.

At least 415 records · Page 23Linked to original sources
PubMed1982

Factors influencing the water proton relaxation in nuclear fractions from tissues of normal and tumor-bearing animals.

Water proton spin-lattice relaxation times (T1) were measured in nuclear fractions from liver, kidney, and spleen tissues from normal and tumor-bearing animals (TBA) at two frequencies. At 9 MHz, the T1 values for TBA nuclear fractions are less than those for normal nuclear fractions, contrary to observations at the cellular level. Trace metal ion concentration and nucleic acid content estimated for these nuclear fractions suggest that the DNA-metal ion interaction might be responsible for the observed differences in the T1 of nuclear fractions at low frequencies.

Animals↗
PubMed1981

Effects of dihydrocodeine, alcohol, and caffeine on breathlessness and exercise tolerance in patients with chronic obstructive lung disease and normal blood gases.

We measured breathlessness and exercise tolerance in 12 patients with chronic airways obstruction, moderate or severe breathlessness, and low or normal arterial carbon dioxide tension, after the patients received dihydrocodeine, alcohol, caffeine, or placebo (through double-blind administration). Forty-five minutes after ingestion, dihydrocodeine had reduced breathlessness by 20 per cent and increased exercise tolerance by 18 per cent, with a reduction in ventilation and oxygen consumption at submaximal work loads but with no change in spirometric volumes. Oxygen also reduced breathlessness and provided additional benefit to that achieved with dihydrocodeine (at three hours after ingestion) when the two were given together: the reduction of breathlessness was 18 per cent with dihydrocodeine; 22 per cent with oxygen; and 32 per cent with dihydrocodeine plus oxygen. Alcohol increased forced vital capacity by 9 per cent, and exercise tolerance by 7 per cent. Caffeine had no deleterious effect on breathlessness or exercise tolerance, despite increasing ventilation during rest and exercise. We conclude that opiates may be valuable for the treatment of breathlessness in selected patients; further evaluation is needed, particularly of the long-term benefits and safety.

Alcoholic Beverages↗
PubMed1981

Inhibition of cell division by interferons: Changes in the transport and intracellular metabolism of thymidine in human lymphoblastoid (Daudi) cells.

The Daudi line of human lymphoblastoid cells shows a high sensitivity towards growth inhibition by human interferons. In cells pretreated with 70 reference units/ml of an interferon preparation for 48 h, the incorporation of exogenous [3H]thymidine into DNA is inhibited by as much as 85%. We are investigating the extent to which this effect reflects a true inhibition of the rate of DNA synthesis or whether it may be caused by changes in the metabolic utilization of exogenous thymidine by the cells. Interferon treatment results in a 30% inhibition of the rate of membrane transport and a 60% decrease in the rate of phosphorylation of [3H]thymidine in vivo. The latter effect is due to a decrease in V of thymidine kinase without any change in the value of Km for this enzyme. In addition to these changes, incorporation of [3H]uridine into DNA, which occurs as a result of the intracellular conversion of this precursor into thymidine nucleotides, is also inhibited by 75%, whereas RNA labelling by [3H]uridine is decreased by only 15% in interferon-treated cells. Thus several different metabolic events associated with thymidine nucleotide metabolism and DNA synthesis in Daudi cells are disrupted by interferon treatment.

Adolescent↗
PubMed1981

Cross-sectional echocardiographic visualization of abnormal systolic motion of the left ventricle in mitral valve prolapse.

In 11 of 34 patients with typical mitral valve prolapse on the M-mode echocardiogram, cross-sectional echocardiography in the apical four-chamber view revealed a characteristic abnormality not previously described. In mid- to late-systole the ventricular septum contracted vigorously, forming a bend or sharp convexity toward the left ventricle, while motion of the posterolateral basal left ventricle was diminished and delayed. This finding was not encountered in 35 other patients with innocent systolic murmurs, or in 15 patients with mitral regurgitation of etiologies other than mitral valve prolapse. This abnormal pattern of left ventricular contraction on cross-sectional echocardiography occurred with equal frequency in patients with holosystolic and late-systolic prolapse; it was seen more frequently in patients with severe prolapse than in those with mild to moderate prolapse.

Adult↗
PubMed1981

Role of serotonin in the nicotine-induced depression of the brainstem auditory evoked response.

We have examined the role of serotonergic and/or dopaminergic mechanism in the mediation of the nicotine-induced depression of brainstem auditory evoked responses (BAER) to auditory stimuli. Nicotine produced dose- and time-dependent decreases in BAER amplitude. Administration of serotonin-depleting drugs (reserpine or p-chlorophenylalanine (PCPA), prevented this decrease. Administration of catecholamine-depleting drugs (alpha-methyl-p-tyrosine, disulfiram or Dopa), on the other hand, had no effect. These data thus suggest a role for serotonergic mechanisms in the mediation of nicotine-induced depression of the brainstem auditory pathway.

Animals↗
PubMed1980

Spontaneous splenic rupture in plasma cell leukemia.

A case of plasma cell leukemia complicated by spontaneous rupture of the spleen is presented. Plasma cell leukemia occurs in less than 2% of patients with myeloma and is associated with an increased incidence of splenomegaly due to infiltration by malignant plasmacytes. Sontaneous splenic rupture is known to occur in patients with acute and chronic leukemia, but has been reported only once previously in a patient with plasma cell leukemia. Etiologic factors and the need for prompt diagnosis and management are discussed.

Female↗
PubMed1980

Ampullary carcinoma associated with multiple duodenal villous adenomas.

A 39-year old Asian with multiple duodenal villous adenomas and an adenocarcinoma arising from one of these tumors is described. The rarity of villous adenomas at this site is stressed and their tendency to undergo malignant change reviewed. Immunoperoxidase studies using carcinoembryonic antigen (CEA) antiserum were positive in high dilutions (1 in 8,000) in the carcinoma and the largest adenoma. This stain would appear to show functional malignancy before histological evidence of malignancy is found.

Adenocarcinoma↗
PubMed1979

Histopathological evidence in support of the association of elevated proton spin-lattice relaxation times with the malignant state.

The pulsed nuclear magnetic resonance technique was explored for its potential diagnostic value in human cancer. Measurements of proton spin-lattice relaxation times (T1) of cellular water protons of normal and malignant esophageal tissues showed elevated T1 values in the latter. In some cases, tissues which appeared normal on gross examination assumed as uninvolved tissues had T1 values higher than the other grossly uninvolved tissues and often closer to the T1 of the corresponding tumor tissue. A histopathological study of the assumed uninvolved areas also studied for the T1 values was therefore undertaken. A preliminary study demonstrated the presence of malignant cell groups or clusters in some of the uninvolved samples with higher T1 compared to the true uninvolved tissues, which had a normal histological picture and low T1 values. This observation has brought out the importance of histopathological studies in addition to relaxation studies to comprehend contributory factors to relaxation. Secondly, it lends support to the thesis of elevated T1 values being characteristics of the malignant state.

Biopsy↗
PubMed1979

Pulmonary toxicity from carmustine (BCNU): a case report.

A patient who had a pneumonectomy for lung carcinoma was treated with carmustine when brain metastases developed. His pulmonary function was mildly compromised prior to the pneumonectomy by many years of smoking. After six months of carmustine therapy [total dose: 2,250 mg (1,200 mg/m2)] he developed interstitial pulmonary fibrosis with histologic changes consistent with drug toxicity. With seven previously reported cases of this drug-effect and the addition of our case, carmustine must be added to the list of cancer chemotherapeutic agents that can cause pulmonary toxicity.

Autopsy↗
PubMed1979

Angiomatous lymphoid hamartoma or pseudolymphoma of pelvic retroperitoneum: clinical significance and evaluation of pelvic ureter.

Angiomatous lymphoid hamartomas or pseudolymphomas have been reported most commonly within the chest and usually are mistaken for thymic tumors of lymphomatous tissue. Pelvic retroperitoneal location, to our knowledge, has been described only on three occasions. Only a high index of suspicion can make one recognize this rare lesion and save unnecessary radical surgery and/or radiation therapy. Removal of the mass led to dissappearance of associated systemic manifestations in many of the patients.

Adult↗
PubMed1979

Pulsed nuclear magnetic resonance studies on nuclear fractions of normal and malignant tissues.

Nuclear fractions isolated from normal liver tissues and an experimental tumor--mouse fibrosarcoma (MFS)--were studied by pulsed NMR. Findings were: (1) T1 values of nuclear fractions are higher than those of the tissues or origin. (2) T1 values of nuclear fractions isolated from liver of tumor-bearers are higher than T1 values of nuclear fractions of normal liver. (3) T1 values of nuclear fractions of MFS tumor are higher than nuclear fractions of liver of tumor-bearing mice. Comparison of T1 values of the nuclear fractions shows a hierarchy of T1 from liver to MFS.

Animals↗
PubMed1978

Mechanism of antihypertensive effect of thiazide diuretics.

Hemodynamic studies were carried out before and during 8 weeks of treatment with hydrochlorothiazide 50 mg. twice daily in 11 hypertensive patients. Forty-eight hours after beginning treatment there was a significant reduction in blood pressure, cardiac output, plasma volume, and extracellular fluid volume (thiocyanate space) while total peripheral resistance increased. After 6 and 8 weeks of treatment, the blood pressure and the plasma and extracellular volumes remained reduced. However, total peripheral resistance fell while cardiac output rose to control levels. These results were consistent with the "reverse autoregulation" theory of the action of the thiazides as proposed by Tobian. The present evidence discussed below makes it appear unlikely that the thiazides have an important direct vasodilator effect.

Antihypertensive Agents↗
PubMed1978

When "lymphoma" is not lymphoma: diagnosing immunoblastic lymphadenopathy.

Immunoblastic lymphadenopathy, a newly described disease, is clinically similar to lymphoma but has a specific histologic picture. It usually does not have malignant potential and is best treated initially by corticosteroid in high doses. Chemotherapy is used when corticosteroid fails or when malignant conversion occurs.

Adult↗
PubMed1978

Lymphoma of the prostate presenting as benign prostatic hypertrophy.

A case of lymphocytic lymphoma involving the prostate is reported. Lymphomatous infiltration of the prostate had been mentioned infrequently in the literature, so that the incidence, prognosis, and treatment are not well known. Lymphomatous or leukemic infiltrate should be considered as a causative agent of prostatism, particularly in patients with hematologic abnormalities where chemotherapy may relieve the symptoms.

Aged↗