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Biomedical subjects

R L Allen

Publications and source records attributed to R L Allen.

66 records · Page 4Linked to original sources
PubMed1983

Freeze-dissection analysis of 133Xe distribution to measure regional renal blood flow.

To verify the freeze-dissection technique for measuring renal blood flow (RBF) distribution in anesthetized dogs we compared the sum of all compartment flow rates with total RBF, compared compartment flow distribution with intercepts, and determined recirculated 133Xe. By dissection, we found that the cortex, delineated by its granular brownish red appearance, comprised 69%, whereas the outer medulla (the reddish portion) was 18% of the total kidney weight. Average cortical flow was 3.77 ml X g-1 X min-1 and the y-intercept for 133Xe washout was 85% of the initial radioactivity distribution. Outer medullary flow was 2.01 ml X g-1 X min-1 with a y-intercept of 13%. In a 100-g kidney, total cortical flow would be 259.8 ml/min (3.77 ml X g-1 X min-1 X 68.9 g) and total outer medullary flow would be 36.0 ml/min. These calculations indicate that 86% of the total flow is distributed to the cortex and 13% to the outer medulla, as the intercept-calculated percentages indicated. Summing whole cortical and medullary flows results in a flow that agrees with the electromagnetically measured flow of 292 ml/min for a 100-g kidney.

Animals↗
PubMed1982

The ability of fetal calf serum, new-born calf serum and normal steer serum to promote the in vitro development of bovine morulae.

The objective of this study was to compare fetal calf serum, new-born calf serum and normal steer serum as medium supplements in the development of bovine morulae in vitro . Bovine morulae were cultured in Hams F-10 tissue culture medium (HF-10) supplemented with 5% or 10% (v/v) fetal calf serum (FCS), new-born calf serum (NBCS) or normal steer serum (NSS). Embryos were recovered at slaughter from mixed bred donor cows of mixed breeding following estrus synchronization with prostaglandin and superovulation with follicle stimulating hormone. A total of 88 morulae were recovered, washed in HF-10 + 1% Bovine Serum Albumin and randomly assigned to treatments. Embryos were cultured in microdrops of medium under paraffin oil at 37 degrees C in a 5% CO(2) humidified atmosphere. Observations for stage of development were made every 24 hours. In vitro development was analyzed by assigning to each embryo a value of 0-5 based on the most advanced stage reached (0= no development, 5= development to a hatched blastocyst). Analysis of variance of these data revealed a significant treatment effect (P<.001) while no level effect or treatment x level interaction was apparent. Comparison of treatment means by Duncans new mulitple range test showed that NSS was superior to NBCS (P<.05) which was in turn superior to FCS (P<.05) as supplements of HF-10 in promoting the in vitro development of bovine morulae.

Journal Article↗
PubMed1982

Induction of estrus and superovulation in seasonally anestrous ewes.

The induction of estrus in 17 previously cycling nulliparous ewes, 9 to 10 months of age, was attempted with Medroxyprogesterone acetate (MAP) pessaries during the early anestrous period (March-April). Ewes were verified to be anestrous by the lack of estrous behavior in the presence of a vasectomized ram and by a radioimmunoassay for serum progesterone in two samples taken 7 days apart showing less than 1 ng/ml serum progesterone. Superovulation was attempted with injections of either FSH or FSH + LH. MAP vaginal pessaries remained in place for a period of 12 days and FSH was administered to all ewes (IM) at 12 hr intervals over a 3 day period; 5 mg was injected twice on day 11 after pessary insertion, followed by 4 and 3 mg injections twice daily on each succeeding day, for a total of 24 mg per ewe. Nine ewes were given 25 mg LH (IV) within 8 hrs after the onset of behavioral estrus in addition to FSH. Ewes were hand-mated to several rams at 12 hr intervals throughout the estrus period. Ovulation and fertilization rates were recorded for each ewe following midline laparotomy and embryo collection. All ewes were in estrus between 36 and 48 hrs after removal of the MAP pessaries. In ewes injected with FSH only, 8 of 8 ovulated with a mean ovulation rate of 6.0 +/- 4.4 and a fertilization rate of 70%. Nine of 9 ewes receiving both FSH + LH ovulated with a mean ovulation rate of 13.9 +/- 13.1 and a fertilization rate of 72%. Statistical analysis by Students t-test resulted in differences in number of ova recovered (P<.05) between FSH only and FSH + LH treated ewes and a trend towards increased ovulation rate in FSH + LH treated ewes. These results show that early seasonally anestrous ewes can be successfully induced and synchronized for estrus with MAP pessaries and the number of ova recovered is increased with the inclusion of LH in the superovulation regime.

Journal Article↗
PubMed1981

Immunosuppression in the mouse by porcine uterine secretory protein.

Experiments were performed to determine whether uterine secretory proteins (PAP) of the pig affect T cell or B cell functions in vivo. T cell functions examined were E-rosette formation (ERF) and cutaneous reactivity (to phytohemagglutinin) in mature BALB/c females. Two ERF experiments of identical design were performed using five groups of ten mice each. Each mouse was presensitized with sheep erythrocytes (SRBC) designated as day 0; and the various groups were treated with saline, pig serum (PS), or PAP at different times. For cutaneous reactivity, the area of erythema at the sensitization site (pinna of ear) was measured, and three groups of 11 mice were used. These groups also received either PS or PAP. B cell function was examined by measurements of hemagglutination titers to SRBC sensitization in BALB/c females treated in two experiments similar to the ERF. T cell functions examined were highly suppressed (p less than 0.01) by PAP given hours, not days, prior to the measurement. The B cell function examined was not affected by PAP.

Animals↗
PubMed1981

The aging eye.

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Aged↗
PubMed1979

The effects of platinum complexes on seven enzymes.

The effects of K2PtCl4, cis-Pt(NH3)2Cl2, and trans-Pt(NH3)2Cl2 on the activities of glyceraldehyde-3-phosphate dehydrogenase, glucose-6-phosphate dehydrogenase, dihydrofolate reductase, fructose-1,6-bisphosphate aldolase, catalase, tyrosinase, and peroxidase have been investigated. All of the enzymes which are thought to have essential sulfhydryl groups (glyceraldehyde-3-phosphate dehydrogenase, aldolase, and glucose-6-phosphate dehydrogenase) were significantly inhibited by K2PtCl4. The other four enzymes studied are not known to have essential sulfhydryl groups, and were not significantly affected by the Pt compounds under the conditions employed. Glyceraldehyde-3-phosphate dehydrogenase was the only enzyme inhibited by all three Pt compounds tested, with K2PtCl4 being the most effective and cis-Pt(NH3)2Cl2 the least effective inhibitor. Semilogarithmic plots of residual activity versus inhibition time indicated that the inhibition reactions were not simple first-order processes, except for the inhibition of glucose-6-phosphate dehydrogenase by K2PtCl4 which appeared to be first-order with respect to enzyme concentration.

Catalase↗
PubMedDate not supplied

How much stress is too much?

"There is no question that a certain amount of stress is good," says one of the chief executives quoted in this article. "If I have a particularly easy week, I can feel an ache or pain, but if I get really busy, I feel really much better." But when managers feel themselves under too much stress, the executive adds pessimistically, then "not only will they burn out in time, but they get erratic and their judgment goes all to hell." These insights reflect one of the authors' main themes: medical research finds stress productive up to a point (which of course varies with the manager), but beyond that point it can be disastrous. The trouble in corporate life seems to be that leaders appreciate the first part of the relationship but not the second. As a consequence, both individiuals and organizations suffer--and suffer greatly. This penalty is unnecessary, the authors believe, because a newly tested, proved, and relatively simple approach to managing stress is available to any corporation that wants to use it.

Administrative Personnel↗
PubMedDate not supplied

External and middle ear trauma resulting from ear impressions.

When taking an impression of the external ear canal and ear, the audiologist is engaged in an invasive procedure whereby a foreign body is first placed into the ear canal and then removed. There is always an element of risk for significant medical problems when a clinician is performing an invasive procedure. Although some minor patient discomfort and, at times, some slight trauma to the ear canal occur when taking ear impressions, the incidence of significant trauma to the external or middle ear appears to be low. The purpose of this report is to provide some illustrative cases of significant external and middle ear trauma as a result of taking impressions of the external ear. Audiologists are advised to develop and implement an appropriate risk management program for taking ear impressions to reduce the potential risks associated with this procedure to their patients and to their practices.

Aged↗