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Biomedical subjects

H Davis

Publications and source records attributed to H Davis.

At least 199 records · Page 11Linked to original sources
PubMed1979

Diet-related toxemia in pregnancy. I. Fat, fatty acids, and cholesterol.

Toxemia in pregnancy (preeclampsia)is characteristerized by a combination of at least two of the following clinical symptoms: hypertension, edema, and proteinuria. In three successive trials over three consecutive years, the dietary intake of a selected number of young pregnant women attending a Maternal and Infant Care Program at Tuskegee Institute were evaluated for total lipids, individual fatty acids, and cholesterol. Women with toxemia or with any of the individual symptoms were identified and women without toxemia or these symptoms served as controls. Results were variable from repetition to repetition in all but the toxemia group and the edema group. The consumption of total lipids and cholesterol was significantly greater in all three trials by both the toxemia and edema groups. Also, total saturated, monounsaturated, and polyunsaturated fatty acids were eaten in greater amounts. The greatest differences were in palmitic acid, stearic acid, oleic acid, and linoleic acid. The proportion of unsaturated fatty acids consumed in all groups was very low. All differences could be attributed primarily to breakfast and dinner meals and were found in the milk, meat, and egg food groups. Although satistical correlations were found between lipid intake and toxemia of pregnancy any specific relationship between the two is still unclear.

Adolescent↗
PubMed1977

Cardiac Death in the first 6 months after myocardial infarction: potential for mortality reduction in the early posthospital period.

In a prospective postmyocardial infarction study of 759 patients aged less than 66 years, 42 posthospital cardiac deaths (42 of 759; 6 percent) occurred during a 6 month follow-up period. The average age of those who died was 53.5 +/- 8.8 (+/- standard error) years, and postmortem examination was obtainedon 36 percent. Almost 60 percent of the 6 month posthospital mortality occurred within 2 months after hospital discharge. Fifty-five percent of the cardiac deaths occurred either outside th ehospital or within hospital emergency departments, and 62 percent of the deaths were sudden (within 12 hours) or unwitnessed. The suspected mechanism of cardiac death was a primary arrhythmia in 62 percent, and a definite or probable myocardial infarction was diagnosed in only 41 percent. Use of digitalis and diuretic and antiarrhythmic agents was significantly (P is less than 0.025) greater in this group during the week before death than in a comparison survivor group; no difference in use of propranolol or tranquilizers was noted between the two groups. Fifty percent of the group that died had two or more of the following factors: death outside the hospital, sudden death, primary arrhythmic death. These findings indicate that a considerable potential exists for reducing cardiac death in the early posthospital phase of myocardial infarction.

Adult↗
PubMed1977

A phase III study comparing the clinical utility of four regimens of 5-fluorouracil: a preliminary report.

A clinical trial involving 462 colon, rectum, and breast cancer patients randomized among four different dosage regimens of 5-FU (an intravenous loading course, a weekly intravenous schedule, a nontoxic schedule, and an oral schedule) has shown a significantly better response among colon-rectum cancer patients for the intravenous loading course. In addition, duration of response and time to progression are also significantly better. Overall survival is approaching significance for the colon rectum group (p value .082). In contrast, breast cancer patients show little difference between treatments. Toxicity is somewhat higher for the loading course.

Administration, Oral↗
PubMed1976

Effects of aprotinin on organ cultures of the rat's kidney.

Fragments of adult renal tissue were maintained as organ cultures for 7 days in HEPES-buffered medium 199, supplemented with 10% calf serum and antibiotics. Addition of aprotinin (10,000 kallikrein inhibitor units per ml) to the medium resulted in improved survival of the cells of the glomeruli and tubules and preserved the integrity of the glomerular, capsular and tubular basement membranes. Optimal results were obtained when aprotinin was present throughout the period of culturing. Inclusion of aprotinin in the medium for only the first 3 days in vitro slightly increased the numbers of surviving glomerular and tubular cells, but also promoted the growth of connective tissue in the explants and was detrimental to the basement membranes of the tubules. It is suggested that both the antiproteolytic and the carbohydrate-binding properties of aprotinin are involved in the mediation of the observed effects.

Animals↗
PubMed1976

Prospective evaluation of treatment of Hemophilus influenzae meningitis.

Fifty children with Hemophilus influenzae meningitis have been enrolled in a prospective study. Patients were randomly assigned chloramphenicol or ampicillin treatment; there were no significant differences between groups in other respects. Countercurrent immunoelectrophoresis proved to be a valuable tool for rapid diagnosis of the causative agent even in pretreated patients. Increasing quantities of capsular polyribosephosphate antigen detected in the initial cerebrospinal fluid correlated significantly (r=0.62419; p less than 0.01) with early and late sequelae of meningitis. None of the patients died. Severe and persistent neurologic or intellectual deficits were noted in four (8%) of the children, and an additional 14 (28%) had IQ scores between 70 and 90. The presence of bactericidal antibody in serum was not protective. Anti-PRP antibody generally was not present in acute serum specimens and irrespective of the quantity of antigenic stimulus provided by the disease was nondetectable in 21 of 24 children less than 17 months of age following recovery.

Adolescent↗
PubMed1976

The early posthospital phase of myocardial infarction. Prognostic stratification.

Prognostic stratification was carried out on 518 patients less than or equal to 65 years of age who were discharged from the hospital following a definite or probable acute myocardial infarction and followed for four months. The total population was made up of 272 patients hospitalzed in 1973 and 246 patients hospitalized in 1974; one hundred and forty-two variables were collected on each patient. The clinical characteristics of the 1973 and 1974 populations were remarkably similar, and both groups had a four-month posthospital cardiac mortality rate of 4%. Two prognostic stratification schemes were developed on the 1973 population which identified low and high risk groups with meaningfully different four-month cardiac death rates. Both stratification schemes were tested on the 1974 population, and one of the two schemes was validated as identifying a significantly increased cardiac mortality rate in the high as opposed to the low risk group. The four-month posthospital cardiac mortality rate was 3% in the low and 14% in the high risk group (Z = 2.70, P less than 0.003). The high risk group was characterized by two or more of the following characteristics: 1) history of angina at ordinary levels of activity or at rest; 2) CCU hypotension and/or congestive heart failure; 3) ventricular premature beat frequency greater than or equal to 20/hr on a six-hour electrocardiographic tape recording. The low risk group had none or only one of the above characteristcis. The prognostic power of this stratification scheme is such that sixteen percent of the posthospital population can be identified as high risk, and this subgroup contains forty-six percent of the patients who die of cardiac cause in the four-month posthospital interval.

Aged↗
PubMed1976

Effects of signals preceding and following shock on baseline responding during a conditioned-suppression procedure.

Long-Evans rats were exposed to a succession of conditioned-suppression procedures involving pairings of (1) signal-shock, (2) shock-signal, and (3) a signal-shock-signal sequence in which first and second signals were at first physically identical. Traditional suppression of food-reinforced responding was obtained under the signal-shock arrangement, and exposure to the shock-signal sequence resulted in conditioned enhancement of responding during the signal. The signal-shock-signal condition reliably suppressed responding during the first signal, but produced no differential effect on response rate during the second signal. Baseline responding was least changed from preshock rates under the signal-shock-signal procedure, but baseline rate was considerably reduced under the signal-shock and shock-signal arrangements, the latter yielding most substantial reductions. A second experiment indicated that the magnitude and direction of changes in baseline responding reported in Experiment I were not confined to cases in which the first and second signals in the signal-shock-signal arrangement were physically identical. It is suggested that the major effects of the conditioned-suppression procedure on response rate might not be confined to presentations of the signal.

Journal Article↗
PubMed1975

The skin in magnesium-deficient rats.

The cutaneous vasodilatation occuring in the early stages of dietary deficiency of magnesium has been investigated in rats. While the time of onset of erythema varies in proportion to the weight of the animal, the duration is not related to weight. In severe states of vasodilatation, the skin is thickened and infiltrated with mononuclear cells, apparently derived from the blood. Intact sympathetic and sensory innervation are not necessary for the development of vasodilatation in the skin. Neither can the genesis of the erythema be attributed to degranulation of mast cells. From consideration of this and other investigations, it is concluded that the cutaneous abnormalities of magnesium-deficient rats cannot be due directly to hypomagnesaemia.

Animals↗
PubMed1975

Action of aprotinin on the survival of adult cerebellar neurons in organ culture.

Fragments of cerebellar cortex taken from adult rats were maintained for 7 days in organ culture. Inclusion in the medium of aprotinin, a polypeptide proteinase-inhibitor which also has carbohydrate-binding properties, was beneficial to the survival of neurons in the molecular layer, Purkinje cells and axons. This effect of aprotinin was mediated during the first 3 days in vitro. In a discussion of the various actions of aprotinin, it is concluded that the principal effect of the polypeptide on cultured central nervous tissue is to inhibit neuronal lysosomal proteinases activated by the trauma of explantation.

Animals↗
PubMed1975

Audiometric comparison of the middle and late components of the adult auditory evoked potentials awake and asleep.

The middle and the late components of auditory evoked potentials were alternately recorded in sequential sets from 28 adults, both awake and asleep. Sleep was induced by secobarbital and was monitored for depth. 1000 c/sec tone pips in one laboratory or filtered clicks in the other were delivered at 10, 20 or 30 dB sensation level. Control collections without stimulation were included. For the middle responses a single simple scoring template and one set of voltage criteria could be used for all stages of waking and sleeping. For late responses different templates and voltage criteria were needed. Estimates of the threshold of detection of the evoked potentials were based on the percentage of clearly positive responses was often not attained at 30 dB SL, i.e., the threshold was indeterminate. In light sleep and awake the middle responses of most subjects gave thresholds more sensitive than the late by 10-15 dB and also fewer indeterminate trials. The results in our two laboratories agreed closely in spite of differences in equipment and details of procedure. The relatively low thresholds of the middle responses (median 17.5 dB SL awake and 15 dB SL in light sleep) suggest that the middle responses must be considered seriously for use in clinical electric response audiometry, even though one of the 28 subjects failed to yield any identifiable middle responses.

Adult↗