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Biomedical subjects

A Khan

Publications and source records attributed to A Khan.

At least 559 records · Page 31Linked to original sources
PubMed1982

Preoperative chemotherapy for giant cell carcinoma of the thyroid.

Reported is the case of a 24-year-old white man with inoperable giant cell carcinoma of the thyroid who achieved tumor regression following therapy with bleomycin, Adriamycin and cisplatinum. After 2 courses of chemotherapy, the tumor was deemed operable, and the patient underwent total thyroidectomy followed by radiation to the neck and upper mediastinum without maintenance chemotherapy. Two-and-one-half years after the initial diagnosis, he developed pulmonary metastases which again responded to Adriamycin and cisplatinum therapy. The above approach suggests that inoperable thyroid carcinoma can be made operable by preoperative combination chemotherapy. This treatment program deserves further exploration for a greater number of patients.

Adult↗
PubMed1982

An unusual cause of cervical adenopathy. Extramedullary hematopoiesis.

A painless lateral neck mass in an otherwise healthy 58-year-old man is a frequent diagnostic problem. We have recently seen such a patient with a cervical neck mass whose preoperative evaluation findings were normal. Excisional biopsy revealed a lymph node exhibiting changes compatible with extramedullary hematopoiesis. This becomes an additional unusual cause of enlarged lateral neck nodes.

Biopsy↗
PubMed1982

Herpes simplex virus infection of isolated autonomic neurons in culture: viral replication and spread in a neuronal network.

Cultures of isolated neurons, derived from the superior cervical ganglion (SCG) of the newborn rat and maintained in the absence of nonneuronal cells, were infected with herpes simplex virus (HSV) type 1. By phase-contrast microscopy, including time-lapse cinematography, cytopathologic changes appeared first in neuronal cell bodies and only approximately 24 hours later were axonal abnormalities detectable. Despite low yields of viral progeny, infection spread readily within the two-dimensional network of neurons and their processes. Immunoperoxidase staining for viral antigens confirmed the replication and spread of virus and revealed that antigen extended along axons during infection. Antiviral antibody added to the overlay medium slowed but did not prevent the spread of infection, indicating that virus passed from neuron to neuron over axonal pathways. Despite alteration of neuronal macromolecular synthesis early in infection, axonal transport is apparently preserved long enough to allow propagation of virus over interconnecting neural pathways.

Animals↗
PubMed1982

An optimized scheme for measurement of the concentrations of the decay products of radon and thoron.

Radon daughter measurement methods have not previously been fully optimized in the presence of thoron daughters, the presence of which leads to an increase in the total potential alpha energy. Taking into account the fluctuations associated with flow rate and concentration as well as the statistics of decay, optimized counting schemes were determined for the daughters of radon and thoron for different sampling times over a wide range of counting intervals. The counting schemes examined were optimized for maximum precision. Counting schemes corresponding to impractically long counting intervals, and counting times which required measurements beyond an 8 hr working shift were rejected. Under these constraints the most appropriate sampling time was found to be 10 min.

Air Pollutants, Radioactive↗
PubMed1982

Monoclonal antibody against a unique antigen on human acute promyelocytic leukemia cell line (HL-60).

An IgM kappa monoclonal antibody (WI-1) reacted against HL-60 cells in indirect immunofluorescence and microcytotoxicity tests. It failed to react against 19 other cell lines representing acute myelogenous leukemia, chronic myelogenous leukemia, lymphocytic leukemias, multiple myeloma, Burkitt's lymphoma, monocytoid cells and virus induced lymphoid cell lines. Normal peripheral blood nucleated cells and bone marrow cells derived from acute granulocytic leukemia, chronic granulocytic leukemia, acute lymphocytic leukemia, and chronic lymphocytic leukemia also failed to react with WI-1. Normal peripheral blood lymphocytes, transferred with mitogens, showed no reaction against the antibody. There was some decrease in the reactivity of the cells, against WI-1, following maturation with dimethyl sulfoxide. However, a large percentage of the cells remained positive after maturation. WI-1 reacted specifically against an antigen on the HL-60 cells which had a molecular weight of about 42,000 dalton. Peripheral blood cells from one patient with acute promyelocytic leukemia failed to react with the antibody. It is possible that acute promyelocytic leukemia is an antigenically heterogeneous disease. A large population of acute promyelocytic leukemia patients needs to be tested to see if the specific antigen on HL-60 cells, detected by WI-1, is demonstrable in other patients with acute promyelocytic leukemia.

Animals↗
PubMed1981

Benzodiazepine dependence: a general practice survey.

This study aims to evaluate the dependence potential of benzodiazepines in general practice. Amongst a sample of 1079 current general practice patients 87 (8.1 percent) were using benzodiazepines. Most of the users were middle to old age females and had chronic physical illnesses. The drug history was extensive (mean--3 years 7 months) and about 39 percent (34/87) of users were currently on a higher dose than the first prescribed dose. Interview of a selected group (40) of benzodiazepine users showed 75 percent (30/40) to be from a lower socio-economic class and 17 percent (7/40) of these reported past experiences consisting of withdrawal phenomena of varying severity. Benzodiazepines appear to have replaced barbiturates in the general practice setting.

Adolescent↗
PubMed1981

The effect of cholesterol on the phase structure of glucolipids from Acholeplasma laidlawii membranes.

1. The packing properties in lipid mixtures containing cholesterol and membrane glucolipids from Acholeplasma laidlawii are modified by varying the amounts of cholesterol, diacylmonoglucosylglycerol and diacyldiglucosylglycerol in the mixtures as well as the temperature and the degree of acyl chain unsaturation. These changes affect both the proportions of different lipids having dissimilar molecular geometries and the geometry of the lipid molecules themselves. 2. All mixtures containing glucolipids with equal amounts of palmitoyl and oleoyl chains formed a lamellar liquid-crystalline phase in the growth temperature range of A. laidlawii, while a reversed cubic liquid-crystalline phase dominated in mixtures containing dioleoyl glucolipids. These lipids formed a reversed hexagonal phase together with 27% cholesterol. Mixtures with lipid compositions occurring in the membranes of living Acholeplasma cells formed a lamellar liquid-crystalline phase. 3. Large amounts of cholesterol and diacylmonoglucosylglycerol, high temperatures and a high degree of cis unsaturation favoured the formation of cubic or hexagonal liquid-crystalline phase structures of the investigated lipid mixtures. Diacylmonoglucosylglycerol and cholesterol are both wedge-shaped. Temperature and cis unsaturation accentuate the wedge-shape properties of the glucolipid molecules. 4. The changes in the lipid composition of A. laidlawii membranes as a response to cholesterol incorporation can be explained by the geometry and packing characteristics of the sterol molecule and the concept of 'fluidity' does not need to be involved.

Acholeplasma laidlawii↗
PubMed1981

Resistance of peripheral autonomic neurons to in vivo productive infection by herpes simplex virus mutants deficient in thymidine kinase activity.

We used a model involving acute and latent herpes simplex virus (HSV) infections of mouse superior cervical ganglia to assess in vivo neuronal infections with two thymidine kinase-deficient (TK-) mutants of HSV type 1. Despite replication of the TK- HSV strains at the site of inoculation in the eyes, little if any viral replication occurred in the superior cervical ganglia, as assessed by the viral titers of ganglion homogenates, viral antigens in tissue sections, and histopathological evidence of cytopathology or inflammation. Cyclophosphamide-induced immunosuppression and treatment with 6-hydroxydopamine, which enhanced productive infections of superior cervical ganglia with TK+ HSV did not induce TK- HSV ganglionic infections. Latent TK- HSV infections were not detected by cocultivation of ganglion explants. Efforts to infect ganglia in culture after they were removed from animals indicated that superior cervical ganglia, and particularly their neuronal elements, resisted productive TK- HSV infection. These results supported the hypothesis that viral thymidine kinase facilitates acute and reactivated productive HSV infections of neurons.

Animals↗
PubMed1981

Transfer factor in the treatment of herpes simplex types 1 and 2.

Transfer factor potentiates cellular immunity and induces interferon. It was because of these properties that transfer factor was tried in 17 patients with recurrent herpes simplex types 1 and 2. Transfer factor was administered in doses ranging from 5 to 10 U/m2 i. m. The interval between injections varied from 1 week to 3 months. 16 patients could be evaluated clinically in whom the recurrence rate decreased from 10.7 +/- 6.1 to 2.1 +/- 2.5 (mean SD). The reduction was statistically significant. 8 patients were completely free of disease while the other 8 had reduced number of episodes during the period of observation, 7 patients had abnormal T cell function as reflected by the low number of T cells or low lymphocyte transformation. Statistically significant improvement in the T cell function was observed. Delayed hypersensitivity skin test reactions also improved significantly.

Female↗
PubMed1981

Osteoid osteomas and osteoblastomas of the spine.

Benign osteoblastic lesions are rare bone tumors and they are usually divided into osteoid osteomas and benign osteoblastomas based on their biological behavior. Both lesions are prevalent in the spine, with the lamina and pedicle being involved frequently. Long diagnostic delays are frequent. Pain, the most prominent symptom, is often nocturnal and is relieved by aspirin in 30 to 40% of patients. Radicular pain occurs in 50% of the patients. The most common physical finding is tenderness in the vicinity of the lesion. Neurological abnormalities are more frequent in patients with osteoblastomas, which frequently extend into the neural canal. Tomograms are invaluable in most patients in whom plain films are normal. The bone scan is one of the most important diagnostic studies and provides an excellent means of accurately demonstrates the location and extent of the tumor. Permanent relief of pain and neurological recovery is dependent primarily on total removal of the lesion.

Adolescent↗
PubMed1981

Total myelography with metrizamide through the lumbar route.

Myelography of the entire spinal cord was performed in 64 consecutive patients using metrizamide via lumbar puncture. Adequate to good opacification of the cervical and thoracic subarachnoid space was obtained in 63 patients. The technical factors responsible for this success rate are patient cooperation, high iodine concentration, high iodine concentration (250 mg/ml), slow injection rate, delayed removal of the needle, minimal patient motion, and rapid performance. Side effects were minor and no more frequent than with lumbar metrizamide myelography alone. Adequate hydration before and after and upright position after seem to be important in minimizing adverse effects.

Adolescent↗
PubMed1981

Conjoined lumbosacral nerve roots. Management of herniated discs and lateral recess stenosis in patients with this anomaly.

Anomalous L-5 and S-1 nerve roots occur infrequently. If not properly recognized, surgery for entrapment disorders may result in serious neural injury because of an improper surgical approach in exposure and in removing the underlying herniated discs. The diagnosis has been made preoperatively since the introduction of water-soluble myelography because of improved filling of the nerve roots. A herniated disc beneath the bifid root causes extreme pain and disability with marked signs of entrapment because of firm fixation of the conjoined root in the lateral recess between the two pedicles. An underlying herniated disc may not be recognized because of the unique anatomical changes. To properly identify the nature of the lesion, wide exposure by hemilaminectomy is preferred, with unroofing of the lateral recesses and wide foraminal decompression. Eight such patients are reported: seven had herniated discs, and one had lateral recess stenosis with superior facet entrapment. With adequate decompression, all patients made a rapid, uneventful recovery.

Adult↗
PubMed1980

Benzodiazepine withdrawal syndromes.

We report eight cases of benzodiazepine withdrawal syndromes seen in a general psychiatric hospital. These consisted of acute organic brain syndrome, grand mal convulsions and abstinence syndromes. All of the cases were using benzodiazepines in prescribed therapeutic doses. These problems appear to be more common than are generally acknowledged.

Adult↗
PubMed1980

Effect of sample pretreatment on sorption of acetophenone by soils and sediments.

The effect of several sample pretreatment storage techniques, the effect of degree of grinding, and the effect or organic matter removal on the sorption of acetophenone was examined. No significant difference in the sorption of acetopheonone was observed when air-dried, freeze-dried, oven-dried, frozen, or samples kept at 2 degrees C (fresh) were compared. All pretreatment storage techniques resulted in linear sorption isotherms and gave good fits to the modified Freundlich equation (Cs = Kp . Cw). No significant differences in sorption constants (Kp) were observed for samples with a 2 mm maximum diameter when compared to samples ground to 0.6 mm maximum diameter or 0.25 mm maximum diameter. Organic matter removal resulted in decreased Kp values for samples containing more than 1% organic carbon initially but increased Kp values for samples containing less than 1% organic carbon before removal. Expandable 2:1 clay mineral content was significantly correlated with adsorption of acetophenone after organic matter removal.

Acetophenones↗