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Biomedical subjects

M D Smith

Publications and source records attributed to M D Smith.

At least 523 records · Page 29Linked to original sources
PubMed1980

Comparison of the effects of vitamin D metabolites on collagen synthesis and resportion of fetal rat bone in organ culture.

We compared the effects of four vitamin D metabolites, 1 alpha,25 dihydroxy vitamin D3 (1 alpha,25(OH)2D3), 1 alpha hydroxy vitamin D3 (1 alpha OH D3), 25 hydroxy vitamin D3 (25 OH D3), and 24R,25 dihydroxy vitamin D (24R,25(OH)sD3) on resorption and collagen synthesis in fetal rat bone maintained in organ culture. Resorption was quantitated by measuring the release of previously incorporated 45Ca from long bone shafts of 19-day fetal rats, and collagen synthesis was assessed by measuring the incorporation of 3H-proline into collagenase digestible protein (CDP) in calvaria from 21-day fetal rats. All four compounds stimulated bone resorption and inhibited collagen synthesis, but 1 alpha,25(OH)2D3 was approximately 1000 times more potent in both organ culture systems. Although the differences were small among the other three compounds, the order of potency was 1 alpha OH d3 > 25 OH D3 greater than or equal to 24R,25(OH)2D3. These results suggest that the receptor for 1 alpha 25(OH)2D3 in both bone resorbing and bone forming cells has similar affinities for several vitamin D metabolites.

Animals↗
PubMed1980

Memory and problem-solving in aphasia.

In a series of experiments, aphasic adults and normal control subjects were presented with problems involving the principle of transitive inference. The design of the problems permitted selective consideration of the subject's logical, as opposed to grammatical, ability and further permitted separate consideration of logical ability and memory. The results of this experimental series showed that, in general, these aphasic patients were capable of successful inferential behavior. In conclusion, the data are interpreted to suggest that certain constraints on intelligence in aphasia occur as a result of defective memory, not defective logical ability.

Adult↗
PubMed1980

Mechanism of interferon action: simian virus 40-specific early polypeptides synthesized in untreated and interferon-treated monkey kidney cells.

The effect of interferon treatment on proteins synthesized in simian virus 40 (SV40)-infected cells in the presence of cytosine arabinoside was investigated. The following results were obtained: (i) In addition to previously described large tumor (T) antigen (94 kilodaltons) and small tumor (t) antigen (19 kilodaltons), a 62-kilodalton polypeptide was immunoprecipitated by SV40 anti-T antiserum from extracts of infected CV-1 and BSC-1 monkey kidney cells and transformed SV3T3 mouse cells. The 94-, 62-, and 19-kilodalton polypeptides were not precipitated with normal serum from extracts of infected cells, and they were not present in extracts of uninfected cells. (ii) The de novo synthesis of the 94-, 62-, and 19-kilodalton tumor antigens was inhibited in CV-1 and BSC-1 cells treated with interferon before infection; total cellular protein synthesis was not significantly affected by interferon treatment. The relative interferon sensitivity of the three polypeptides in lytically infected monkey cells was comparable; by contrast, interferon did not affect their synthesis in transformed mouse cells. (iii) The 62-kilodalton polypeptide was detected in monkey cells infected with the following strains of SV40: tsA30 at both 33 degrees C and 41 degrees C; wt 708, the parent of tsA30; dI 884; and wt 830, the parent of dI 884. The amount of the 62-kilodalton species relative to T antigen was significantly greater in tsA30-infected cells as compared to cells infected with other SV40 strains. (iv) T, t, and 62-kilodalton polypeptides were readily labeled with [(35)S]methionine during a 10-min pulse; in a subsequent chase, the (35)S-labeled 94-kilodalton T antigen was apparently converted to 89- and 84-kilodalton polypeptides but not to either the 62-kilodalton polypeptide species or t antigen. (v) Partial peptide maps suggest that the 62-kilodalton polypeptide and T antigen are closely related. (vi) In addition to the above described 62-kilodalton polypeptide, a 54-kilodalton polypeptide was also detected. However, the 54-kilodalton species appears to be of cellular origin because it was immunoprecipitated with both normal and anti-T antiserum from uninfected and lytically infected cells and from virally transformed cells.

Animals↗
PubMed1980

Platelet monoamine oxidase and plasma amine oxidase in psychiatric patients.

Platelet monoamine oxidase (MAO) and plasma amine oxidase (PAO) activities were determined in 70 normal controls and 76 psychiatric patients. Platelet MAO activity did not differ between the normal controls and patients diagnosed as schizophrenic or primary affective illness, although there was a strong trend for chronic schizophrenics to have lower MAO activity. Schizophrenic patients with Schneiderian-type hallucinatiions had significantly lower MAO activity than normal controls or schizophrenic patients who did not hallucinate. There was no relationship between hallucinations and platelet MAO activity in patients with affective psychoses. Paranoid schizophrenics did not have significantly different MAO activity from nonparanoid schizophrenics. PAO activity was generally lower in all diagnostic groups than in normal controls, but the results were statistically significant only for acute schizophrenics.

Affective Disorders, Psychotic↗
PubMed1980

Characteristics of death education curricula in American medical schools.

To determine the content, structure, objectives, and organization of death education curricula in American medical schools, a cross-sectional survey was developed. The data, representing 100% of the population, demonstrated that such curricula expanded markedly during the past decade. The developmental stimuli for death education, sources of funding, and objectives of death education curricula were relatively consistent across respondents. Conversely, course content, faculty and patient roles, learning resources, and involvement in curriculum research did not evidence a systematic development. The results of the study suggest the need for a further investigation of the clinical implications of death education.

Cross-Sectional Studies↗
PubMed1980

Improved method for conjugative transfer by filter mating of Streptococcus pneumoniae.

The frequency of conjugation during filter mating of pneumococcus was increased 10- to 100-fold when the filter was embedded in agar during incubation instead of being on the surface. The major effect was not due to protection from oxygen. The factor of increase was similar for transfer of plasmids and of chromosomal insertions of drug resistance elements.

Agar↗
PubMed1980

Henoch-Schönlein purpura: report of case.

A case of Henoch-Schönlein purpura in a man has been presented. The patient was a typical candidate for the disease, with a history of major allergies and antecedent events of an upper respiratory infection and ingestion of at least two drugs previously implicated as etiologic agents. However, no specific allergen was identified and tests to verify it as an example of a circulating immune complex disease were not successful. The patient had many of the commonly found symptoms of HSP and additionally had the rare complications of both genital involvement and intraoral lesions. The disease ran its course in approximately eight weeks; there is little reason to believe that the patient will have a recurrence.

Humans↗
PubMed1980

The detection of circulating immune complexes in renal transplant patients.

The Raji cell assay and radiolabelled Clq binding method were used to detect circulating immune complexes in the sera of renal transplant patients. Complexes were found in seven of twelve patients using the Raji cell assay; only one serum sample was positive by the Clq method. In five patients the complexes were detected prior to the clinical diagnosis of rejection and in those in whom treatment reversed the rejection the complexes rapidly disappeared. The presence of complexes correlated with a vascular type of rejection characterised by fibrin deposits in the glomeruli in the absence of immunoglobulin or C3 deposits. In two patients, in whom anti red cell antibodies were present, irreversible rejection occurred without the presence of detectable complexes in the sera.

Adult↗
PubMed1979

High-performance liquid chromatographic determination of hydrocortisone and methylprednisolone and their hemisuccinate esters in human serum.

A high-performance liquid chromatographic method is described for the simultaneous determination of methylprednisolone (MP) and methylprednisolone hemisuccinate (MPHS), or hydrocortisone (HC) and hydrocortisone hemisuccinate (HCHS) in human serum. Reversed-phase liquid chromatography was performed on a microparticulate C18 column (Spherisorb, 5 micron) using a mobile phase of 2% glacial acetic acid, 30--35% acetonitrile, 70--65% water with ultraviolet detection (254 nm). The method uses 17 alpha-hydroxyprogesterone as the internal standard for the determination of methylprednisolone and its hemisuccinate ester, or 11-deoxy-17-hydroxycorticosterone as the internal standard for the determination of hydrocortisone and its hemisuccinate ester. The sensitivity is 0.03 microgram/ml for HC, 0.07 microgram/ml for MP, 0.04 microgram/ml for MPHS, and 0.10 microgram/ml for HCHS, with a detection limit of 0.02 microgram/ml for all four steroids. Calibration curves are linear up to 3 micrograms/ml for MP or MPHS (as equivalent MP) and up to 4 micrograms/ml for HC and 7 micrograms/ml (as equivalent HC) for HCHS. The pooled relative standard deviation for replicate for each steroid is less than 7%. Plasma concentration--time curves are reported for MP and MPHS or HC and HCHS of two human subjects following intramuscular administration of 125 mg of methylprednisolone sodium succinate for injection, U.S.P., or 250 mg of hydrocortisone sodium succinate for injection, U.S.P.

Chromatography, High Pressure Liquid↗
PubMed1979

Pedunculated pharyngeal lesions.

Dentists enjoy a unique position in the health care field because they examine and treat more intraoral disease than any other specialty. It is, therefore, the responsibility of the dentist to examine the entire oral cavity and not just the teeth. Thorough intraoral examination may reveal undiagnosed pathological lesions which arise outside the oral cavity but are pedunculated and present in the mouth or oropharynx. The article presents three cases of such lesions which are potentially life threatening but may be cured if detected and treated early.

Adenocarcinoma↗
PubMed1979

Circulating immune complexes and C3d in human parasitosis.

Using the Raji cell radioimmune assay, we found low levels of circulating immune complexes (IC) in a small percentage of patients with schistosomiasis and filariasis. C3d levels, measured by immunoprecipitation, were elevated in a large number of these patients, whereas complement levels were within normal limits. Proteinuria was not found in any of the 55 patients studied. Circulating IC or elevated C3d levels were not found in any of the 19 patients with hydatidosis. The increased C3d levels, apparently not related to circulating IC, may be due to direct complement activation by parasite antigens or to sequestered IC. The latter hypothesis appears more attractive because the highest levels of C3d were found in schistosomiasis whereas schistosome antigens were unable to activate complement in vitro.

Antigen-Antibody Complex↗
PubMed1979

A plasmid in Streptococcus pneumoniae.

Plasmid deoxyribonucleic acid has been detected in three related laboratory strains of Streptococcus pneumoniae. Strains D39S, R36, and R36NC each contain a minimum of two copies per cell of a 2.0-megadalton plasmid (pDP1). A plasmid twice as large as this smaller one is also present in much lower quantity in these strains, but neither plasmid is present in four strains related to these or in a drug-resistant clinical isolate from Paris. The plasmid yield was not amplified in the presence of chloramphenicol. No phenotype has been correlated with the presence of pDP1, which has existed in strains carried for many years in laboratory collections.

Anti-Bacterial Agents↗