Biomedical subjects

S T Lu

Publications and source records attributed to S T Lu.

At least 55 records · Page 3Linked to original sources

PubMed1980

Delineating acute neuroendocrine responses in microwave-exposed rats.

One hundred and eighteen male rats (Long-Evans) were acclimated to experimental procedures (i.e., handling, transferring from and back to "home" cage, body weight and colonic temperature determinations) for 2 wk and then subjected to cage confinement for 3 days before microwave (MW) exposure to 2,450 MHz for 1-, h, at 1-70 mW.cm-2 or sham exposure at ambient temperature of 24 +/- 1 degree C. Colonic temperature increased after exposure to power densities greater than or equal to 20 mW.cm-2 and was the most sensitive parameter measured. Inverse relationships between corticosterone and thyrotropin or growth hormone were noted after exposure for 1 h at 50 mW.cm-2 and above. Pituitary-thyroid function was inhibited after exposure to 20 mW.cm-2 for 2-8 h. Changes in other hormones were transient or inconsistent. Corticosterone, thyrotropin, and growth hormone levels could be correlated with power density or colonic temperature in rats exposed to MW for 1 h; corticosterone and thyrotropin levles correlated with colonic temperatures in shams. Body temperature influences adenohypophysial hormones in studies of MW biological effects.

Animals↗

PubMed1980

The granulomatous response of leprosy patients to lepromin and killed BCG.

The volunteers studied included 6 tuberculoid and 11 lepromatous leprosy patients (Ridley and Jopling). Each received intradermally 0.1 ml of lepromin (Wade method) and 0.1 ml of autoclaved BCG (grown on Dubos medium) at 2 separate sites on the left upper arm. Observations were made at weekly intervals, and biopsy specimens were taken at the fourth wk. Within 3 to 4 wk all 6 tuberculoid patients responded to lepromin with typical granulomas (5 of which measured 5 mm or more in diameter) composed of epithelioid cells, lymphocytes and giant cells. In contrast, 8 of the 11 lepromatous patients remained negative; the other 3 developed tiny papules less than 3 mm in diameter which disappeared after 2 wk. Biopsy specimens taken from injection sities at the fourth wk showed essentially normal histology. All 1 patients developed typical granulomas to heat-killed BCG (non were less than 5 mm in diameter and most were larger) consisting of epithelioid cells, many lymphocytes and a few giant cells. The reaction in tuberculoid leprosy was stronger than that in lepromatous leprosy and the reaction to BCG in tuberculoid leprosy was stronger than that to lepromin, but the differences were not very remarkable.

Adult↗

PubMed1979

Microwaves: effect on thermoregulatory behavior in rats.

Rats, with their fur clipped, pressed a lever to turn on an infrared lamp while in a cold chamber. When they were exposed to continuous-wave microwaves at 2450 megahertz for 15-minute periods, the rate at which they turned on the infrared lamp decreased as a function of the microwave power density, which ranged between 5 and 20 milliwatts per square centimeter. This result indicates that behaviorally significant levels of heating may occur at an exposure duration and intensities that do not produce measurable changes in many other behavioral measures or in colonic temperature. Further study of how microwaves affect thermoregulatory behavior may help us understand such phenomena as the reported "nonthermal" behavioral effects of microwaves.

Animals↗

PubMed1978

Studies of the lymphatic drainage of dog lungs.

The lymphatic system of the lungs has proved difficult to study and characterize because it is technically complex to investigate, its properties are difficult to quantitate, and anatomically it is extraordinarily variable. This study was part of a more comprehensive effort to understand the nature of lymphatic permeation by extrinsic materials (e.g., dusts) arising from alveolar deposition, and had three main objectives; (1) to develop a reliable surgical approach for the collection of lymph from the right duct; (2) to investigate some of the inconsistencies in lymphatic structure and function, especially the relationship of the right lymph duct (RLD) and thoracic lymph duct (TLD) outflows to the pulmonic lymph; and (3) to begin a systematic investigation of lymphatic uptake of administered materials by varying their physicochemical parameters. Ultimately, we utilized a modification of the surgical approach of Meyer, which we believe is less prone to blood contamination than the venous-sac procedure of Leeds and Uhley and provides purer pulmonic lymph. By this means we obtained average RLD flow rates of 4.5 ml/h or 0.35 ml/h . kg body weight in 24 dogs, which are comparable to those in the recent literature. For demarcation of the pulmonic drainage in relation to the RLD and TLD, we found in 13 dogs that 75% or more of the lung lymph returned to the venous circulation through the RLD, wheras less than 3% of the thoracic lymph entered the RLD. Radioactive tracers were administered by intralymphatic, intrabronchial, inhalation, and intravenous routes to obtain these findings and the uptake data. Lymphatic uptake values for iron, cadmium, and lead were obtained principally after intrabronchial administration. The uptake data, while preliminary, indicate that both the chemical species and their physical states are important in affecting alveolar permeation into the pulmonic lymph. Evidence for varying lymphatic roles in the alveolar retention of these heavy metals is also presented.

Animals↗

PubMed1977