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Biomedical subjects

R E Gold

Publications and source records attributed to R E Gold.

At least 19 recordsLinked to original sources
PubMed1992

Exposure of applicators and residents to chlordane and heptachlor when used for subterranean termite control.

Research was conducted to assess dermal and respiratory exposure to applicators from chlordane and heptachlor used for subterranean termite control and exposure to residents of treated homes. Dermal exposure of 29 applicators was evaluated by using gauze pads attached to outer and inner clothing at selected body regions. Respiratory exposure of applicators was monitored with personnel-type air samplers worn during application periods. Air samplers were equipped with polyurethane foam plugs to trap airborne chlordane and heptachlor. Exposure of residents was measured by sampling ambient air of 19 homes treated with the termiticides. Electric air samplers equipped with foam plugs were used to monitor ambient air from the basement, the kitchen, and one bedroom at: 24 h prior to termiticide application, during application, and post-application at 24 h, 1 wk, and monthly for 6 mo. Applicator dermal exposure was estimated based on exposure rates to each body region. Respiratory exposure was estimated based on termiticide concentrations in the air and on the ventilation rate of a person doing light work. Residents' exposure was estimated based on the amount of termiticide present in ambient air. Results indicated that applicator exposure rates to chlordane and heptachlor were 2.54 and 1.88 micrograms/kg/h, respectively. Residents were exposed to less than 0.69 and 2.86 micrograms/m3 of chlordane and heptachlor, respectively. During this research, the application of termiticide containing chlordane and heptachlor posed minimal risk in terms of acute exposure to either the applicators or the residents of the treated homes.

Air Pollution, Indoor↗
PubMed1992

Inhibition of interleukin-2-stimulated enhancement of human natural killer (NK) cell activity by carbaryl, an anticholinesterase insecticide.

The potency of the anticholinesterase (antiCHE) insecticides as serine hydrolase inhibitors, and evidence for serine hydrolase activity in interleukin-2 (IL2) signalling suggest that the natural killer (NK) cell may be a target for dysregulation by antiCHE insecticides. NK cells are large granular lymphocytes (LGL) that respond to IL2 by proliferating and increasing their cytolytic efficiency. In the present study, we assessed the effects of carbaryl (CA, an antiCHE insecticide) and alpha-naphthol (NA, the major metabolite of CA) on both target cell killing per se and IL2 enhancement of target cell killing by human NK cells. Human LGL, collected from the peripheral blood of normal donors, were cultured for 4 days with human recombinant IL2 (HRIL2), then assayed by a 51Chromium (51Cr) release assay for lytic activity against human K562 cells. When added at the beginning of the culture period, CA inhibited enhancement of cytolytic efficiency in a concentration-dependent manner; at concentrations (0.5 and 5.0 microM) compatible with no cholinergic toxicity. Reduction of the effector/target cell (E/T) ratio in the 51Cr release assay markedly enhanced the observed inhibition by CA. In one experiment, inhibition increased from 6% to 20%, 17% to 35%, and 53% to 73% at 0.5, 5.0, and 50 microM CA, respectively, when E/T was reduced from 10:1 to 2.5:1. This result is consistent with reduced cytolytic efficiency of individual NK cells exposed to CA. NA had no effect at 0.5 or 5.0 microM but caused some inhibition at 50 microM. Neither CA nor NA produced LGL death. When CA or NA was added directly to the 51Cr release assay, inhibition was not observed. The mechanism of inhibition of IL2-stimulated enhancement of target cell killing is not yet known, however, the results are consistent with impairment of IL2 signalling, by CA.

Adult↗
PubMed1992

Preoperative embolization of the spleen in children with hypersplenism.

Splenomegaly associated with myelodysplastic disorders in children may be massive and can result in pancytopenia, abdominal discomfort, and respiratory distress. When these symptoms cannot be relieved by nonsurgical means, splenectomy may be indicated. Under such conditions, surgical splenectomy carries increased risks, as the thrombocytopenia is difficult to correct secondary to splenic sequestration. Additionally, the surgical anatomy is often distorted secondary to the massive spleen and dissection can be difficult. These factors can lead to uncontrollable hemorrhage. In an attempt to decrease intraoperative blood loss, the authors successfully performed preoperative splenic artery embolization in 11 of 12 children (age range, 1-11 years) with pancytopenia due to hypersplenism. Hypersplenism requiring surgical splenectomy was due to leukemia (n = 9), myelodysplastic syndrome (n = 1), immune thrombocytopenia (n = 1), and osteopetrosis (n = 1). Embolization was performed under general anesthesia, prior to surgery, with gelatin sponge particles alone, Gianturco coils alone, or a combination of polyvinyl alcohol sponge particles and Gianturco coils. Embolization allowed for safe surgical splenectomy.

Child↗
PubMed1992

Bite-count evaluation of the repellency of N,N-diethyl-3-methylbenzamide to larval Eutrombicula alfreddugesi (Acari: Trombiculidae).

Larvae of the pest chigger mite Eutrombicula alfreddugesi Oudemans, 1910, exhibited a low repellent threshold for N,N-diethyl-3-methylbenzamide (deet) in a field setting. Use of a deet-based repellent significantly reduced chigger mite infestation. Efficacy of aerosol formulations was significantly diminished with 9% (AI) deet. E. alfreddugesi utilized both direct and indirect paths to infest the human body. Direct infestation led to the highest body region bite counts. Distribution of E. alfreddugesi bites over 15 regions of the human body fell into three zones of decreasing parasitism: the ankle/calf region (accessed through direct infestation); the groin, chest, back, armpits, and feet (accessed through indirect infestation); and the thighs, arms, buttocks, head, and neck, which were infrequently attacked or were unavailable to E. alfreddugesi.

Animals↗
PubMed1991

Modulation of interleukin-2-driven proliferation of human large granular lymphocytes by carbaryl, an anticholinesterase insecticide.

Studies in other laboratories have provided evidence that the interleukin-2 (IL2) signaling pathway in lymphocytes includes essential, serine proteases. Since the anticholinesterase (antiCHE) insecticides are potent serine hydrolase (esterase and protease) inhibitors, we assessed the ability of carbaryl (CA, a widely used antiCHE insecticide) and alpha-naphthol (NA, a major metabolite of carbaryl) to modulate IL2-driven proliferation of large granular lymphocytes (LGL) purified from human peripheral blood. These cells express nearly all of the natural killer (NK) activity of human peripheral blood. NK cells are normal lymphocytes that respond to IL2 by proliferating and increasing their tumoricidal activity on a per cell basis. Cultures of purified LGL, initiated in the presence of human recombinant IL2, were harvested on culture Day 4, then proliferation was measured as [3H]thymidine incorporation. When added only at the time cultures were initiated. CA inhibited incorporation 10-32%, 35-53%, and 54-57% at 0.5, 5.0, and 50 microM, respectively. In contrast, NA had no effect at 0.5 and 5.0 microM, but was inhibitory (16-17%) at 50 microM. Reexposure to CA or NA, during the incorporation assay, had little effect on the observed inhibition profiles. Chemically induced changes in cell number during an 8-day culture period reflect the chemically induced changes in [3H]thymidine incorporation. Neither CA nor NA produced cell death. Quantitation of both CA and NA by HPLC indicated a rapid loss of CA (ca. 95% in 24 hr) and a much slower loss of NA from the culture medium. CA inhibited human LGL proliferation at concentrations producing little or no inhibition of serum CHE, an indicator of exposure to antiCHE insecticides.

Adult↗
PubMed1991

Polysplenia syndrome in the asymptomatic adult: computed tomography evaluation.

Although the majority of patients with polysplenia syndrome will present during infancy or childhood with congenital heart disease, 5% to 10% will have no cardiac disease; and the associated abnormalities may not be discovered until adulthood. Physicians should be familiar with the chest and abdominal radiographic findings so as not to confuse this syndrome with other, more common pathologic conditions in asymptomatic adult patients.

Azygos Vein↗
PubMed1989

Laundry parameters as factors in lowering methyl parathion residue in cotton/polyester fabrics.

Cotton/polyester fabrics were contaminated with a 1.25% solution of methyl parathion (MeP) emulsifiable concentrate formulation, then laboratory laundered. The laundering variables were detergent type, concentration, water volume, and mechanical agitation. Specimens were unfinished (UN) and soil repellent finished (SR) fabrics. Heavy duty liquid and phosphate-built powdered detergents were equally effective when used in combination with a prewash product. A negative linear relationship between detergent concentration and MeP residue remaining after laundering was established. An interaction between detergent concentration and fabric finish was observed. Soil repellent finished fabrics required detergent concentrations above the recommended amount for more efficient soil removal. A negative linear relationship between water volume and after-laundering residue was observed. Water volume played a more significant role in pesticide removal than agitation during laundering.

Chromatography, Gas↗
PubMed1989

Silent deep vein thrombosis in immobilized multiple trauma patients.

Although few trauma patients sustain fatal pulmonary embolism, a large population is at risk from nonfatal embolism due to unrecognized deep vein thrombosis (DVT). Thirty-eight of 39 immobilized trauma patients at bed rest for 10 days or longer had venographic study of their lower extremities to evaluate for the presence of silent DVT. Sixty percent of patients had silent DVT, with thrombi extending above the knee in half the patients with clot. DVT was documented in 67 percent of patients with major lower extremity fractures and 59 percent of patients without major fractures. DVT increased with increasing age but not with injury severity score.

Adult↗
PubMed1989

Auditory thresholds in the American cockroach (Orthoptera: Blattidae): estimates using single-unit and compound-action potential recordings.

Recent commercial suggestions that insect populations can be controlled through the use of ultrasound raises the question of whether or not certain insects have receptors that are sensitive to high-frequency sound. Single neural unit discharges and compound-action potentials were recorded from the ventral nerve cord in the American cockroach, Periplaneta americana L., to constant rise time tone pulses from 100 to 40,000 hertz (Hz). Unit responses and compound-action potentials show that the cockroach is insensitive to sound above approximately 3,000 Hz. Data relating latency of the response to intensity of the stimulus suggest that the cockroach cercal system operates on the principle of energy envelope detection. Decreases in latency likely occur primarily as a result of increases in the rate of membrane depolarization in cercal dendrites.

Action Potentials↗