PubMed Health⌕ Search

Biomedical subjects

T Downs

Publications and source records attributed to T Downs.

27 records · Page 2Linked to original sources
PubMed1985

Production of monoclonal antibodies against parainfluenza 3 virus and their use in diagnosis by immunofluorescence.

Monoclonal antibodies were produced against parainfluenza virus type 3 (PI-3) and used to identify PI-3 clinical isolates in cell culture and PI-3 antigen in cells obtained from nasopharyngeal (NP) washes of patients. Two (2E9 and 4G5) of the three monoclonal antibodies characterized reacted by immunoblotting with a 67,000-dalton PI-3 protein, and one antibody (4E5) reacted with two viral proteins in the range of 29,000 to 31,000 daltons. The three monoclonal antibodies did not cross-react by indirect immunofluorescence (IFA) with PI-1 or PI-2 and identified by IFA 18 isolates of PI-3 in cell culture. The 2E9 antibody reacted with PI-3 antigen in cells of 8 NP wash specimens that also yielded PI-3 in cell culture. Cells from 12 specimens reactive by IFA for respiratory syncytial virus, 1 specimen yielding adenovirus in cell culture, and 5 specimens yielding influenza virus were not reactive.

Animals↗
PubMed1984

Extrahypothalamic growth-hormone-releasing factor (GRF) secretion is a rare cause of acromegaly: plasma GRF levels in 177 acromegalic patients.

To assess the frequency with which acromegaly is caused by ectopic secretion of GRF, we collected plasma samples from 177 unselected acromegalic patients. The samples together with those of three acromegalic patients with previously diagnosed tumors secreting GRF and of normal subjects were assayed in 3 independent GRF RIAs. Plasma immunoreactive GRF (IR-GRF) levels in normal subjects were either undetectable or detectable at levels up to 62.5 pg/ml. In none of the 177 specimens from acromegalic patients were IR-GRF values detectable in all assays, and in the most sensitive assay, the levels were similar to those in normal subjects, with the highest level measuring 82 pg/ml. In contrast, plasma IR-GRF found in the 3 patients with tumors that secreted GRF ranged from 2.0-24.4 ng/ml. These data suggest that extrahypothalamic GRF secretion is a rare cause of acromegaly. However, it is important that this rare cause of acromegaly be diagnosed before the patient has unnecessary surgery and/or irradiation directed at the pituitary. We recommend that plasma IR-GRF be measured in each new acromegalic patient.

Acromegaly↗
PubMedDate not supplied

Is there transplacental transfer of asbestos? A study of 40 stillborn infants.

An autopsy study was conducted to investigate whether there is transplacental transfer of asbestos in humans. The asbestos burden of lung, liver, skeletal muscle, and placenta digests of 40 stillborn infants was determined using a bleach digestion method. The fibers detected in the tissue digests were characterized as to the type of asbestos, using electron microscopy, energy-dispersive x-ray analysis, and selected-area diffraction analysis. Placental digests of 45 full-term, liveborn infants were similarly processed as controls. Low levels of small, thin, uncoated asbestos fibers were detected in the placentas and organs of 37.5% of the stillborn infants (15 of 40). The fiber sizes ranged from 0.05 to 5.0 microns in length and 0.03 to 0.3 micron in width, with a mean length of 1.15 microns and a mean width of 0.069 micron. Maximum numbers of fibers were found in the lungs (mean 235,400 fibers/g; n = 10), followed by liver (mean 212,833 fibers/g; n = 6), placenta (mean 164,500 fibers/g; n = 4), and skeletal muscle (80,000 fibers/g; n = 1). The fibers were detected at all stages of gestation and showed no association with gestational age. A significant association was found between fiber presence and working mothers, and positive but nonsignificant associations were found with maternal history of drug abuse, previous abortions, and fetal maceration. No association was found between premature rupture of membranes and fiber presence. No fibers were detected in the 45 placentas of the liveborn control infants. There was a highly significant difference in the asbestos fiber counts of the placentas of the stillborn and liveborn infants (P < .001). Our studies demonstrate the presence of short and thin asbestos fibers in stillborn infants and their positive association with working mothers.

Asbestos↗
PubMedDate not supplied

Ovine fetal-placental cocaine pharmacokinetics during continuous cocaine infusion.

OBJECTIVE: To investigate fetal-placental cocaine clearance, and to determine the fetal catecholamine and cardiovascular responses to continuous intravenous cocaine infusion in fetal sheep. METHODS: Eleven pregnant ewes and their fetuses (127 +/- 2 days' gestation; term 150 days) were chronically instrumented. Fetuses received intravenous cocaine at 0.05, 0.1, or 0.2 mg/kg/minute. Fetal cardiovascular and hematologic measurements were made before and serially for 90 minutes after initiation of the cocaine infusion. RESULTS: Steady-state fetal plasma cocaine concentrations were observed by 15 minutes of infusion and averaged 136 +/- 11, 318 +/- 65, and 610 +/- 36 ng/mL, respectively, at each dose. Fetal-placental cocaine clearance rate was independent of dose (337 +/- 39 mL/kg/minute), indicating that it is a first-order pharmacokinetic process. Fetal plasma concentration of benzoylecgonine, a principle cocaine metabolite, increased throughout the study to approximately 25% above cocaine levels by 90 minutes. There were significant increases in fetal heart rate (from 169 +/- 11 to 242 +/- 36 beats per minute), mean blood pressure (from 53 +/- 4 to 63 +/- 5 mmHg), and systolic blood pressure (from 68 +/- 2 to 80 +/- 5 mmHg), with a corresponding increase in catecholamine levels seen in the fetuses infused with 0.2 mg/kg/minute. These changes were not seen in the fetuses given lower doses of cocaine. CONCLUSION: Fetal-placental clearance of cocaine is a rapid, first-order pharmacokinetic process. During prolonged cocaine exposure, plasma benzoylecgonine concentrations accumulate significantly. Significant catecholamine and cardiovascular changes are seen in fetal sheep with a continuous infusion of cocaine at 0.2 mg/kg/minute or greater.

Animals↗