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Biomedical subjects

M Smith

Publications and source records attributed to M Smith.

At least 829 records · Page 46Linked to original sources
PubMed1991

Depressed subjects unwittingly overreport poor social adjustment which they reappraise when recovered.

Potential biases due to acute depressive symptomatology on raters' assessments of social maladjustment derived from patients' reports were assessed in 25 patients responding to pharmacotherapy during medium-term hospitalization. Patients were questioned on two separate occasions about their social maladjustment covering the exact same period (the 4 months preceding hospitalization): the first was during the acute illness phase, and the second a mean of 20.5 days later, when symptoms remitted. In the second report, composite scores for all fields as a whole showed significantly fewer reports of social impairment than did the first. Significant differences from the first to the second evaluation concerning both subjective distress and observable behavior were found in four and three, respectively, of the five "fields" of social adjustment. Although subjective distress was most modified by remission of acute symptoms, even supposedly objective, observable disturbances were significantly affected. These results indicate that acutely depressed patients overreport social maladjustment, which they then more accurately reappraise when symptoms remit. Patients are completely unaware of both the initial bias and of the reappraisal.

Acute Disease↗
PubMed1991

Process, costs, and outcomes of community-based prenatal care for adolescents.

An evaluation of a community-based prenatal care program for teens compared 180 adolescent clients with a sample of adolescents matched on age and year of delivery who received care through a traditional prenatal care program at a university medical center. Evaluation criteria describing the process of receiving care were the mean number of prenatal visits, nonscheduled outpatient visits, nonstress tests, ultrasounds, and inpatient days during pregnancy. The two programs were significantly different as measured by these criteria. Outcome criteria included gestational age, birthweight, the percentage of infants requiring neonatal intensive care, and the percentage of clients with maternal complications. A multivariate analysis showed no statistically significant differences in these outcomes. The average cost of resources consumed during prenatal care for the study group was 41% that of controls.

Adolescent↗
PubMed1991

A comparison of serum and saliva paracetamol concentrations.

The relationship between serum and saliva paracetamol concentrations was investigated in twenty healthy volunteers. The plasma and saliva drug concentrations showed a significant correlation (r = 0.67). However the agreement between the two methods of measurement was poor with limits of agreement of -15.3 mg l-1 to +15.9 mg l-1 with mean sample values of 19.2 and 19.5 mg l-1 for plasma and saliva, respectively.

Acetaminophen↗
PubMed1991

Characterization of a short, cis-acting DNA sequence which conveys cell cycle stage-dependent transcription in Saccharomyces cerevisiae.

Comparison of the 5'-flanking regions of several cell cycle-regulated DNA replication genes of Saccharomyces cerevisiae has revealed the presence of a common sequence, 5'-ACGCGT-3', which is upstream and proximal to mapped transcription initiation sites. This sequence, which is the cleavage site for the restriction endonuclease MluI, is present twice in the upstream region of the yeast thymidylate synthase gene TMP1. Previous studies have implicated these MluI sites as critical components in the cell cycle-dependent transcription of TMP1. In this study, we examined more closely the importance of the ACGCGT sequences for the transcription of this gene. Using site-directed mutagenesis in combination with deletion analysis and subcloning experiments, we found that (i) while both of the TMP1 MluI sites contribute to the total transcription of this gene, the distal site is predominant and (ii) the 9-bp sequence ACGCGTTAA encompassing the distal MluI site exhibits properties of a cell cycle-stage dependent upstream activation sequence element. The results of this study support the notion that the ACGCGT sequence is an integral component of a transcription system which coordinates the cell cycle-dependent expression of DNA replication genes in S. cerevisiae.

Base Sequence↗
PubMed1991

Depletion of c-myc with specific antisense sequences reverses the transformed phenotype in ras oncogene-transformed NIH 3T3 cells.

ras oncogene-transformed NIH 3T3 cells expressing glucocorticoid-inducible antisense c-myc cDNA transcripts at levels sufficient to deplete c-myc protein lost their transformed morphology and the ability to grow in soft agar; their ability to form tumors in nude mice was also impaired. These changes were dependent on the continuous expression of the antisense sequences. No major effects on plating efficiencies, growth rates in monolayer culture, or immortalization were observed in the revertant cells, indicating that the observed effects were not a toxic consequence of c-myc protein depletion. Transfection with the same vector expressing c-myc in the sense orientation or other control vectors had no effect on transformation. These results suggest that a certain minimum level of expression of c-myc is required for the maintenance of ras transformation in NIH 3T3 cells.

Animals↗
PubMed1991

Quasi-simultaneous measurement of ionized calcium and alpha-granule release in individual platelets.

The effect of alpha-thrombin and ADP on calcium mobilization and alpha-granule release in individual platelets was investigated by flow cytometry. alpha-Thrombin (4.5 nM) caused a uniform rise of free cytosolic calcium ([Ca2+]i) among indo-1-loaded human platelets. Despite the uniformity of this effect, approximately 20% of the cells failed to secrete alpha-granule content, as shown by binding of fluorescein isothiocyanate (FITC)-conjugated S12 monoclonal antibody. ADP (10 microM) caused a similar brisk and uniform rise of calcium but did not increase S12 binding to any platelets. On the other hand, with alpha-thrombin (0.5 nM), calcium mobilization was heterogeneous and paralleled granule release. [Ca2+]i increased rapidly in some platelets, while only slowly in others. When an electronic gate was set according to FITC-S12 fluorescence, cells with a greater secretory response proved to be those with a higher calcium level. With both alpha-thrombin and ADP, chelation of external calcium by EGTA (2 mM) reduced calcium response of individual cells. NiCl2 (1 mM) also inhibited calcium rise of individual platelets to the same extent as EGTA (2 mM) in spite of the presence of 1 mM CaCl2 in the extracellular media. The effects of EGTA and NiCl2 were not limited to a particular subpopulation of cells. These data suggest that the putative Ni2(+)-inhibitable divalent cation channel(s) may be responsible for the increased influx of calcium that occurs during platelet activation by alpha-thrombin and ADP. It appears that these calcium channels contribute to the elevation of [Ca2+]i among virtually all the platelets.

Adenosine Diphosphate↗
PubMed1991

Calcium mobilization and glycoprotein IIb-IIIa complex ligands in epinephrine-stimulated platelets.

In the presence of extracellular Ca2+, epinephrine induces a rise in cytoplasmic Ca2+ ([Ca2+]i) that is associated with fibrinogen binding to the platelet surface, platelet aggregation, and enhancement of the thrombin-stimulated [Ca2+]i rise and protein phosphorylation. Whether the [Ca2+]i rise induced by epinephrine results from Ca2+ entry associated with fibrinogen binding to its receptor on the platelet surface, the glycoprotein (gp) IIb-IIIa complex, is unknown. To determine the importance of the occupancy of the gp IIb-IIIa receptor on platelet function after epinephrine administration, we studied the effects of two monoclonal antibodies (M-148 and 7E3) and two synthetic peptide analogues to fibrinogen (synthetic tetrapeptides Arg-Gly-Asp-Ser (RGDS) and dodecapeptide His-His-Leu-Gly-Gly-Ala-Lys-Gln-Ala-Gly-Asp-Val [gamma-(400-411)]), all of which bind to gp IIb-IIIa and inhibit fibrinogen binding and platelet aggregation on the epinephrine-induced rise in [Ca2+]i and enhancement of thrombin's phosphorylation of the 47-kDa substrate of protein kinase C (p47). None of the gp IIb-IIIa ligands significantly enhanced or inhibited the epinephrine-induced [Ca2+]i rise or its augmentation of p47 phosphorylation after thrombin administration; however, the synergistic [Ca2+]i rise that follows addition of both epinephrine and thrombin was reduced by both antibodies and both peptides. Thus ligand binding of gp IIb-IIIa does not influence the epinephrine-induced [Ca2+]i rise or its promotion of protein kinase C activation by thrombin; these events can be dissociated from the synergistic [Ca2+]i rise.

Antibodies, Monoclonal↗
PubMed1991

Bilirubin as an antioxidant: effect on group B streptococci-induced pulmonary hypertension in infant piglets.

Bilirubin scavenges toxic oxygen radicals in vitro, but it is not known whether this potential salutary effect can be extended to the intact animal. Accordingly, the present experiments tested the hypothesis that bilirubin protects against oxygen radical-dependent pulmonary hypertension and arterial hypoxemia in piglets infected with group B streptococci (GBS). Piglets ranging in age and weight from 7 to 14 days and 1.5 to 2.0 kg, respectively, were infused for 60 min with 108 cfu GBS/kg/min. One group of 7 animals was pretreated with a bolus infusion of 15 mg/kg of bilirubin followed by a continuous bilirubin infusion. A second group of 7 animals was given the vehicle. While plasma bilirubin levels in control animals were negligible, administration of exogenous bilirubin was associated with plasma levels of 13.0 +/- 0.74 mg%. Piglets treated with exogenous bilirubin exhibited GBS-induced increases in pulmonary arterial pressure and decreases in PaO2 of 16.1 +/- 2.0 and 46.5 +/- 4.3 torr, respectively. In control animals, GBS increased pulmonary arterial pressure and decreased PaO2 by 17.5 +/- 1.6 and 47.9 +/- 3.2 torr, respectively. Neither the peak changes in pulmonary arterial pressure or PaO2 nor the time courses of these alterations differed between treatment groups. These observations indicate that bilirubin fails to prevent GBS-induced pulmonary hypertension and arterial hypoxemia in infant piglets and suggests that in this particular model bilirubin does not exhibit appreciable oxygen radical scavenging activity.

Animals↗
PubMed1991

Computer-assisted instruction in otolaryngology: the use of a database for examination review.

A database of questions and answers has been developed to assist residents in reviewing current topics in otolaryngology-head and neck surgery. Each question/item has an associated answer, general category, specific category, and reference that allows cross-referencing on the computer system. The user can search the database for categories of interest and obtain a specific subset of questions. This allows an efficient means of knowledge acquisition and review for Board examinations. Additional data entry is also facilitated to expand the database as desired. Currently there are more than 2300 items in the database.

Computer-Assisted Instruction↗