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Biomedical subjects

A Khan

Publications and source records attributed to A Khan.

At least 541 records · Page 30Linked to original sources
PubMed1984

Carcinogenic and toxicologic effects of inhaled ethylene oxide and propylene oxide in F344 rats.

The chronic inhalation toxicity and carcinogenicity of ethylene oxide (EO) and propylene oxide (PO) were evaluated in a 2-year inhalation bioassay. Five groups of male weanling Fischer 344 rats, 80 per group, were exposed at 0 ppm (shared control; filtered air), 50 ppm EO, 100 ppm EO, 100 ppm PO, or 300 ppm PO (7 hr/day, 5 days/week) for 104 weeks. Body weights from rats exposed to EO and PO at all exposure concentrations were significantly reduced compared to controls. A statistically significant increase in mortality was observed in all groups of exposed rats compared to controls. Skeletal muscle atrophy in the absence of any sciatic nerve neuropathology was found in rats exposed at 100 ppm EO and 300 ppm PO. Statistically significant associations between EO exposure and an increased incidence of the following rat neoplasms were observed: mononuclear cell leukemia, peritoneal mesothelioma, and mixed cell brain glioma. Among rats exposed to PO there was a dose-dependent increase in the incidence of complex epithelial hyperplasia in the nasal passages, and two adenomas were detected in the nasal passages of rats exposed at 300 ppm PO. The incidence of adrenal pheochromocytomas was elevated in both PO exposure groups, but not in a dose-related manner. All rat groups were affected by an outbreak of Mycoplasma pulmonis infection which occurred about 16 months into the study. This infection alone and in combination with the epoxide exposures affected the survival of rats in this study, and influenced the development of the proliferative lesions in the nasal mucosa of the PO-exposed rats. No treatment-related changes in any clinical chemistry or urinalysis indices were detected. PO exposure did not increase the incidence of the three neoplasms associated with EO exposure; however, adrenal pheochromocytomas and proliferative lesions of the nasal cavity were increased in rats exposed to PO.

Animals↗
PubMed1984

Delusional depression. Phenomenology, Neuroendocrine function, and tricyclic antidepressant response.

The authors studied clinical variables, family history, cortisol secretion, and 4-week tricyclic antidepressant response in 13 delusional and 12 non-delusional, hospitalized depressives. Comparison in these parameters between the two groups revealed more family history of depression but less of alcoholism, greater frequency of cortisol hypersecretion, and poorer response to tricyclics in the delusional group. This lack of complete response was found despite full remission of delusions in 84.6% of the delusional subjects. The clinical and theoretical implications of these findings are discussed.

Adult↗
PubMed1984

Electrets for passive radon daughter dosimetry.

Electrets are demonstrated to collect radon-daughter aerosols with efficiencies which are similar to the efficiencies of aluminum discs held at a potential equal to the surface potential of the electrets. The properties of the electrets are suitable for incorporation of an electret into a radon-daughter dosimeter as the passive collecting element.

Aerosols↗
PubMed1984

Dexamethasone suppression test in recently detoxified alcoholics: clinical implications.

An overnight dexamethasone suppression test (DST) was performed on 66 nondepressed primary alcoholics, a mean of 20.79 +/- 11.5 days after last alcohol intake. The Beck Depression Inventory (BDI) was given concurrently. Only 6% of the subjects were nonsuppressors. There was no correlation between cortisol levels at 17 and 24 hours postdexamethasone and the age of the subjects or duration of abstinence. There was a low level correlation between cortisol values at 24 hours and the BDI scores. Review of published data indicates that the DST may be abnormal in alcoholics in the first 2 weeks of abstinence, probably a result of abnormal liver function and withdrawal phenomena. DST response of alcoholics resembles that of normal controls after more than 2 weeks of abstinence. Alcoholics with clinical features of depression and an abnormal DST after 2 weeks of abstinence may be candidates for antidepressant therapy or electroconvulsive therapy.

Adult↗
PubMed1984

Sinus histiocytosis presenting as a mediastinal mass.

A 32-year-old man with a ten-year history of bilateral cervical adenopathy, parotid gland swelling, and a posterior mediastinal mass, presented with headaches. A CAT scan of the head revealed a suprasellar mass. Craniotomy and biopsy of this lesion led to a diagnosis of sinus histiocytosis.

Adult↗
PubMed1984

Oblique hilar tomography and mediastinoscopy. A correlative prospective study in 100 patients with bronchogenic carcinoma.

One hundred patients with bronchogenic carcinoma had oblique hilar tomography preoperatively to evaluate the pulmonary hila. Subsequently, all of these patients underwent mediastinoscopy or thoracotomy or both. Hilar and mediastinal nodes were evaluated for the presence of metastasis. These findings were then correlated with the radiographic findings of oblique hilar tomography. We found oblique hilar tomography to be a useful method of selecting patients for mediastinoscopy. The negative predictive value of oblique hilar tomography for mediastinal involvement was 95 percent, while the positive predictive value was 75 percent. Thus, patients with negative findings on oblique hilar tomography need not undergo mediastinoscopic examination prior to thoracotomy.

Adult↗
PubMed1984

Stimulation of natural killer cells in two random-bred strains of athymic rats by interferon-inducing pyrimidinone.

We tested the effect of 2-amino-5-bromo-6 phenyl-4 pyrimidinol (ABPP), an interferon (IFN) inducer, on NK cell cytotoxicity in various tissues of athymic and euthymic rats. Significant augmentation of NK cell cytotoxicity was observed in SP, PB, PE, lung, and liver of adult rats. Cytotoxic potential was also induced by ABPP in young rats, not exhibiting cytotoxicity before the treatment. Cytotoxic cells were detected in nylon wool-filtered fraction, and were not removed by carbonyl iron treatment. Separation on Percoll gradient indicated that ABPP-stimulated cytotoxic SPC resided in LGL-enriched fractions and some of them exhibited less dense characteristics than SPC from untreated rats. The ABPP-mediated cytotoxicity was thymus-independent; both athymic and euthymic rats were equally augmented. The observation that only tissues displaying NK cell augmentation produced significant levels of IFN suggest possible involvement of IFN in ABPP-mediated augmentation.

Animals↗
PubMed1984

Osteoporosis relative to head and neck.

Osteoporosis generally represents changes in the skeletal mass encountered in various groups of disorders. In the head and neck region, however, the term has been used to describe radiologic findings which would be better described in relation to each specific disease entity. A brief review of these diseases is presented. This review led to the conclusion that perhaps the term osteoporosis should be replaced by another suitable and more specific term for these bony changes.

Cushing Syndrome↗
PubMed1984

The dexamethasone suppression test: interaction of diagnosis, sex, and age in psychiatric inpatients.

A group of 277 semiconsecutive psychiatric inpatients manifesting a depressive affect underwent an overnight 1 mg dexamethasone suppression test (DST) and a semistructured diagnostic interview according to DSM-III criteria. For major depressive syndromes (major depression with and without psychosis, bipolar depressed) the sensitivity of the DST was 63.9%, specificity 73.0%, and diagnostic confidence 72.3%. Additionally, a significant interaction between age and baseline cortisol values and nonsuppression rates was found in depressed males but not in nondepressed males nor in depressed and nondepressed females. The authors discuss the implications of these findings.

Adolescent↗
PubMed1984

Monoclonal antibody (WI-2) reactive against human transformed and leukemic cells.

A monoclonal antibody (WI-2) was produced against HL-60 cells. This antibody was IgM Kappa and reacted with human cell lines derived from fibroblasts and from hemopoetic, lymphoid, and neoplastic tissues. It also reacted with lymphocytes transformed by mitogens. WI-2 lacked reactivity against normal human RBC's, mature granulocytes, and T and B lymphocytes. The target antigen for WI-2 had a molecular weight of 43,000 daltons. Specimens from patients with leukemia were tested with WI-2. The number of immature cells was compared with the number of WI-2 reactive cells in the peripheral blood and bone marrow and subjected to linear regression analysis. There was a highly significant (p less than 0.001) correlation between the two parameters. The antibody may be useful in monitoring the progress of the patients and in detecting early relapse in leukemia.

Animals↗
PubMed1983

Use of heart cell cultures as a tool for the evaluation of halothane arrhythmia.

The effects of various combinations of epinephrine-halothane and epinephrine-enflurane were tested on beating myocardial muscle cells cultured from 2- to 3-day-old rats. A series of culture plates containing myocytes were exposed to 0.5, 1.0, 1.5, and 2% halothane. At each halothane concentration, 9 ng of epinephrine was added, and the rate of contraction and rhythm of myocytes were observed. With increasing halothane concentrations, a significant and progressive increase in the percentage of plates demonstrating arrhythmia was observed. In a separate series of experiments, doses of epinephrine were added following exposure to 1.5% halothane. As the dose of epinephrine was increased progressively more plates displayed arrhythmia. In addition, culture plates were exposed to enflurane (3 and 6%), and epinephrine was added to each plate. No arrhythmia was observed in any of the 3% enflurane exposed plates. However at 6%, 100% of the plates displayed arrhythmia. In another series of experiments the efficaciousness of quinidine, procaine amide, lidocaine, propranolol, and verapamil in converting cell culture arrhythmia to normal rhythm following epinephrine and halothane was tested. Quinidine converted 96% of all arrhythmic plates to normal rhythm, procaine amide 80%, lidocaine 50%, and propranolol 10%. Verapamil failed to convert any arrhythmic plates to normal rhythm. It was concluded from this study that halothane directly "sensitizes" heart cells in tissue culture, and that the "sensitization" process is a linear, dose-dependent phenomenon.

Action Potentials↗
PubMed1983

A nontoxic adjuvant treatment for advanced head and neck cancer.

A variety of adjuvant chemotherapy programs have been described for advanced head and neck cancer. The protocol described herein is nontoxic and particularly appropriate for patients with advanced tumors who cannot, because of severe pulmonary disease, tolerate bleomycin sulfate. Eighty percent of patients treated with this combination responded with more than 50% tumor shrinkage. Chemotherapy was followed by either surgery, radiation therapy, or both. Long-term control with this combined modality therapy was better in oral cavity and oropharyngeal lesions than in tumors from the hypopharynx.

Aged↗
PubMed1983

Mouse monoclonal antibody (WI-MN-1) against malignant melanoma.

A mouse monoclonal antibody, WI-MN-1, was raised against G-361 melanoma cell line. Reactivity of this antibody was characterized by indirect immunofluorescence against 22 cell lines and normal and neoplastic human tissues. Positive reactions were seen against three melanoma cell lines (G-361, HT-144, and MeWo). It also reacted against an epidermoid carcinoma cell line (Hep-2) and amnion cells (WISH). The antibody failed to react against cell lines derived from granulocytic leukemias, lymphocytic leukemias, Burkitt's lymphoma, carcinoma of the lung, carcinoma of the cervix, carcinoma of the colon, carcinoma of the breast, astrocytoma, and a human monocytoid cell line. Mouse melanoma and mouse fibroblast cell lines were also nonreactive. Similarly, there was no reaction against human peripheral blood, bone marrow, spleen, lymph node, thymus, breast, lung, stomach, heart, brain, kidney, liver, skin, or testis. The antibody was also tested by indirect immunofluorescence against 17 samples of metastatic malignant melanoma which were removed from 13 patients. WI-MN-1 gave positive reaction against 16 of these specimens, and it reacted with the cryostat section in the immunoperoxidase test, delineating neoplastic melanoma from the normal brain tissue. The antibody precipitated Mr 105,000 and 38,000 antigens from biosynthetically labeled G-361 cells. It was suggested that WI-MN-1 was a useful addition to the panel of monoclonal antibodies against melanoma-associated antigens.

Animals↗
PubMed1983

Monoclonal antibody against myeloid leukemia cell line (KG-1).

A murine monoclonal antibody (WI-5) was produced against a myeloid leukemia cell line (KG-1). The antibody was immunoglobulin G3K. It reacted only against KG-1 cells and failed to react against 33 other cell lines representing fibroblasts, solid tumors, and cells of myeloid and lymphatic origin. It also showed no reaction against normal red blood cells, granulocytes, platelets, monocytes, and T- and B-lymphocytes. Similarly, there was no reaction against lymphocytes transformed by mitogens. Peripheral blood and bone marrow samples from acute granulocytic and acute lymphocytic leukemia, chronic granulocytic leukemia, chronic granulocytic leukemia in blastic crisis, and chronic lymphocytic leukemia failed to react with WI-5. It was suggested that WI-5 detected a unique antigen on KG-1 cells.

Antibodies, Monoclonal↗