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Biomedical subjects

L Harris

Publications and source records attributed to L Harris.

At least 199 records · Page 11Linked to original sources
PubMed1978

The effects on polymorphonuclear leucocyte function of prednisolone and azathioprine in vivo and prednisolone, azathioprine and 6-mercaptopurine in vitro.

The effects of prednisolone azathioprine and 6-mercaptopurine on polymorphonuclear neutrophil chemotaxis, phagocytosis, and killing of Staphylococcus aureus and Candida albicans have been studied. In twenty patients with a functioning kidney graft, taking both azathioprine 2.5 mg/kg/day and prednisolone (mean dose 0.59 mg/kg/day; range 0.30-1.0 mg/kg/day), the polymorphonuclear function did not significantly differ from that in either twenty-two normal or eighteen uraemic controls. Addition of prednisolone, 1.2 X 10(-5) M, azathioprine, 2.1 X 10(-5) M, and 6-mercaptopurine, 2.1 X 10(-5) M, using each drug alone, to normal human polymorphonuclear cells in vitro did not significantly alter their function. It is concluded that prednisolone and azathioprine together in vivo and that both these drugs and 6-mercaptopurine singly in vitro have no significant deleterious effect on polymorphonuclear function and do not contribute, in this way, to the increased susceptibility of patients receiving these drugs to infection.

Adolescent↗
PubMed1978

Hematologic parameters for wild and captive nine-banded armadillos (Dasypus novemcinctus).

Hematologic parameters were determined at capture and during captivity for nine-banded armadillos. Compared to the time of capture, the mean erythrocyte counts were significantly lower after 6 months in captivity. After 1 year in captivity, the mean hematocrit was significantly higher and the mean neutrophil count in males was significantly lower. Although the number of armadillos sampled was greater than in previous research, the variation within groups was large.

Animals↗
PubMed1977

Picosecond laser study of fluorescence lifetimes in spinach chloroplast photosytem I and photosystem II preparations.

Fractions enriched in either Photosystem I or Photosystem II have been prepared from chloroplasts with digitonin. A more detailed analysis of the decay kinetics of fluorescence excited by a picosecond laser pulse has been possible compared to experiments with unfractionated systems. The Photosystem I fractions show a very short component (less than or equal to 100 ps) at room temperature which is apparently independent of pulse intensity over the range of photon densities used (5 - 10(13)--1 - 10(16) photons cm-2). The Photosystem II fraction has a short initial lifetime at room temperature which is strongly intensity-dependent approaching 500 ps at low photon densities, but decreasing to close to 150 ps at the highest photon densities. All of these room temperature decays appear to be non-exponential, and may possibly be fitted by at t1/2 expression, expected from a random diffusion of excitations via Förster energy transfer. On cooling to 77K, lifetimes of both Photosystem I and Photosytem II increase, the lengthening with Photosystem I being more striking. The Photosystem I decays become intensity dependent like the Photosystem II, and at the lowest photon densities decays which are more nearly exponential within the experimental error give initial lifetimes of about 2 ns. The non-exponential decays seen at high photon densities appear to fit a t1/2 expression.

Chloroplasts↗
PubMed1977

Effects of intravenous tetrahydrocannabinol on experimental and surgical pain. Psychological correlates of the analgesic response.

Two intravenous doses of tetrahydrocannabinol (THC) (0.022 mg/kg and 0.044 mg/kg) were compared to intravenous diazepam (0.157 mg/kg) and to placebo (Ringer's lactate) as premedication for dental extraction in 10 healthy volunteers. Pain detection and tolerance thresholds were measured and psychiatric interviews were supplemented by Minnesota Multiphasic Personality Inventories (MMPI), the Zung Depression Scale (ZDS), Beck Depression Inventories (BDI), and the State-Trait Anxiety Inventory (STAI). Pain detection thresholds were altered unpredictably with high THC doses, but analgesia as indicated by pain tolerance was less than that after diazepam and placebo. In three subjects low-dose THC (0.022 mg/kg) was a better analgesic than placebo but not diazepam. Six subjects preferred placebo to low-dose THC as an analgesic; this group experienced increases in subjective surgical pain and were submissive, rigid, and less introspective with high State Anxiety and MMPI profiles that differed from subjects whose pain was not increased. STAI following THC presaged a poor analgesic response in this group.

Adolescent↗
PubMed1977

Regional hyperplastic lymph nodes in breast cancer: the role of lymphocytes and nodal macrophages. An immunological study with a five-year follow-up.

Five stage I and stage II breast cancer patients with sinus histiocytosis in two or more enlarged regional lymph nodes were studied. Peripheral lymphocytes, serum, and nodal lymphocytes were tested in vitro for cytotoxicity against autologous normal and tumor cells. Nodal macrophages were incubated with autologous peripheral lymphocytes and these "activated" lymphocytes then were tested in vitro for cytotoxicity against autologous normal and tumor cells. Peripheral lymphocytes (L) were not cytotoxic to autologous tumor (T) cells at 25:1 L/T ratios. Nodal lymphocytes were specifically cytotoxic to autologous tumor cells. Macrophages from hyperplastic regional lymph nodes transferred tumor specific inmunity to peripheral lymphocytes. Macrophages from small, nonhyperplastic regional lymph nodes did not transfer tumor specific immunity. With the advent of adjuvant chemotherapy and its attack on systemic immunity, a quantitative, immunopathological classification of breast cancer patients is needed in order to properly select patients for further therapy.

Adenocarcinoma, Scirrhous↗
PubMed1976

Fluorescence lifetimes of Chlorella pyrenoidosa.

The flucrescence decay of Chlorella pyrenoidosa has been investigated under a variety of conditions in the picosecond and nanosecond time regions. Most of the fluorescence is accounted for by an expression of the form I(t) = I0exp-(At+Bt1/2) though an additional exponential term is required to include a weak component of lifetime 32 ps observable only at the higher pulse intensities. This interpretation reconciles earlier and apparently conflicting data. The weak 32 ps component may be associated with Photosystem I, although the possibility that it is an artefact of the high intensity pulses used cannot be excluded at present. The main fluorescence, described by the equation above is attributed to the antenna chlorophyll and is of the form which would be expected from a single light harvesting array with trapping at randomly distributed sites.

Chlorella↗
PubMed1976

Some problems of therapeutic trials in hypertension.

It is strongly recommended that a scientific protocol for controlled therapeutic trials in hypertension should include, inter alia, the following: 1. A definition of the level(s) of blood pressure which indicate hypertension (systolic and/or diastolic), preferably related to age and sex. 2. The criteria for defining the type of hypertension (e.g., essential, renovascular, etc.). 3. A statement relative to which diastolic level is to be recorded: phase IV ("muffling") and/or phase V ("disappearance"). 4. Information on the sizes of sphygmomanometer cuffs to be used. 5. A statement of which arm is to be used (throughout the study). 6. A statement of postures in which blood pressure is to be measured (supine, sitting, standing). 7. Information on the conditions under which pressures are to be recorded (e.g., "casual," "near-basal," etc.) and the duration of rest before recording. 8. Details of the times of day at which measurements are to be taken.9. A statement on the method of establishing baseline readings (e.g., mean of three successive readings) and the acceptable degree of variability (e.g., +/- 10 mm Hg). 10. A definition of "endpoints" (e.g., diastolic pressure less than upper limit of normal; reduction in diastolic pressure greater than 10 mm Hg).

Antihypertensive Agents↗
PubMed1976

Trace mineral deficiencies in rats caused by feeding rapeseed flours during growth, gestation and lactation.

The present study determined the effect of duration of feeding and dietary levels of rapeseed flours on growth, outcome of gestation and lactation and blood trace element content of rats. In the first two experiments, female rats were fed either casein or rapeseed flour diets during gestation and lactation, or prior to and during gestation. In the last two experiments, weanling male rats were fed for 4 weeks either casein or rapeseed flour diets with or without added zinc. Feeding rapeseed flours prior to and/or during gestation caused a reduction in weight gains and food consumption but did not affect the number or weight of the pups born. Plasma zinc levels were low in the mother rats at parturition and plasma zinc and iron levels were low in weanling rats after 4 weeks of feeding the rapeseed diets. Adding 300 ppm zinc to the diet prevented the decrease in food consumption, weight gains and plasma zinc levels in the weanling rats. It is concluded that the recommended levels of trace elements in the rat diet are inadequate for the purpose of bioassay and toxicological evaluation or rapeseed preparations. In order that the nutritional potenital of new protein sources be correctly evaluated, guidelines for adequacy of mineral in such diets should be determined.

Animals↗