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Biomedical subjects

A Bailey

Publications and source records attributed to A Bailey.

At least 163 records · Page 9Linked to original sources

Electromyographic activity of the nonpregnant and pregnant sheep uterus.

Myometrial electromyograms were studied in nonpregnant ewes, pregnant ewes throughout the second half of gestation, and during labor and delivery in normal spontaneous vaginal delivery and premature delivery induced by the continuous infusion of synthetic adrenocorticotropin 1-24, 1 microgram x h-1, to the fetus at 120 and 130 days' gestation. The bursts of electromyographic (EMG) activity during estrus were very similar to those seen in the pregnant ewe in the second half of gestation. In the second half of gestation, the bursts of EMG activity lasted a mean of 6.7 minutes and occurred at intervals of 54.7 minutes in utero, without an incision for fetal instrumentation, and were 7.2 minutes in duration, occurring every 46.6 minutes when the uterus had been incised. EMG activity occurred simultaneously at most recording sites within the uterus. There was no evidence to support the view that a uterine pacemaker exists with a fixed location. As delivery approached, the mean duration of each EMG burst began decreasing more than 24 hours before delivery, and the frequency of the bursts increased, demonstrating that the recording of uterine electromyograms provides a precise and sensitive method for the study of the early changes that lead to labor and delivery.

Animals↗

Relationship of cholecystokinin receptor binding to regulation of biological functions in pancreatic acini.

Cholecystokinin (CCK) was conjugated to 125I-Bolton-Hunter reagent (125I-BH-CCK), and the binding of this ligand to CCK receptors in isolated mouse pancreatic acini was correlated with the regulation by CCK of both amylase release and the transport of 2-deoxyglucose and alpha-aminoisobutyric acid. Stimulation of amylase release by CCK was biphasic. At low CCK concentrations (less than 200 pM), amylase release was progressively stimulated, whereas at higher CCK concentrations (greater than 200 pM), amylase release was progressively reduced. In contrast, stimulation of 2-[3H]deoxyglucose transport and inhibition of alpha-[3H]aminoisobutyric acid transport were monophasic, being one-half maximal at 0.85 and 0.44 nM, respectively. Under incubation conditions identical to those employed for measuring biological functions, the binding of 125I-BH-CCK to receptors in acini was rapid and reversible. Competition-inhibition curves and Scatchard plots of equilibrium binding were compatible with two orders of binding sites. Employing a computer program for analysis of multiple binding sites, a high-affinity, low-capacity binding component having a Kd of 26 pM and a lower-affinity, higher-capacity binding component having a component Kd of 2.2 nM were resolved. Regulation of 2-[3H]deoxyglucose and alpha-[3H]aminoisobutyric acid uptake appeared, therefore, to be the result of fractional occupancy of the lower-affinity CCK receptors. Regulation of amylase released was more complex and appeared to be due to the concomitant occupancy of both the high- and low-affinity CCK receptors.

Amylases↗

Serum cotinine levels in pipe smokers: evidence against nicotine as cause of coronary heart disease.

Serum levels of cotinine (a principal metabolite of nicotine) were studied in men who did not smoke (28), and in men who smoked cigarettes only (150), cigars only (70), and pipes only (56). The mean cotinine level for pipe smokers was 389 ng/ml, significantly higher than the mean level for cigarette and cigar smokers (306 and 121 ng/ml, respectively); no cotinine was detected in the serum from any of the non-smokers. Large prospective studies have shown that pipe smokers have no material excess risk of coronary heart disease but cigarette smokers do, so that our observations indicate that nicotine is unlikely to be the major cause of the excess coronary heart disease mortality in cigarette smokers.

Adult↗

The importance of tar and nicotine in determining cigarette smoking habits.

Cigarette consumption and inhaling, assessed using carboxyhaemoglobin levels, were studied in 1786 men to investigate the importance of tar and nicotine as determinants of smoking habits. No prior warning was given that smoking habits would be studied. Neither nicotine nor tar yields materially influenced the number of cigarettes smoked a day. Both nicotine and tar yields were negatively associated with inhaling (p less than 0.001) but after allowing for either of the two yields the effect of the other on inhaling was no longer statistically significant. There was, therefore, no indication as to whether nicotine or tar was the more important determinant of smoking habit.

Carbon Monoxide↗

Carbon monoxide in breath in relation to smoking and carboxyhaemoglobin levels.

Carboxyhaemoglobin (COHb) levels were studied in 11 249 men. The distribution among the 2613 men who smoked cigarettes was well separated from that in 6641 non-smokers (including ex-smokers). The distribution for 2005 cigar and pipe smokers was intermediate, though some of the highest COHb levels occurred in cigar smokers. Using a COHb cut-off level of 2%, 81% of cigarette smokers, 35% of cigar and pipe smokers, and 1.0% of non-smokers had raised COHb levels. In a subsidiary experiment alveolar air samples were collected from 162 smokers and 25 non-smokers using a simple breath sampling technique. Carbon monoxide concentrations in alveolar breath were highly correlated with COHb levels (r = 0.97) indicating that COHb levels can be estimated reliably by measuring the concentration of carbon monoxide in breath. Alveolar carbon monoxide measurement is thus a simple method of estimating whether a person is likely to be a smoker.

Adult↗

THe relationship between myometrial activity and sleep state and breathing in fetal sheep throughout the last third of gestation.

Between 106 and 144 days' gestation, periods of uterine electromyographic (EMG) activity and associated increases in uterine tone (contractures) were accompanied by a change in fetal ocular activity in 294 (63%) of 467 cases. In 260 (88.4%) of the changes, there was a switch fromm the active to nonactive state. The incidence of this change was significantly greater (p < 0.01) than the switch from the nonactive to the active state. The fetal electrocorticogram changed state in 34 (74%) of 46 contractures, the change being from low-amplitude to high-amplitude activity in 28 (82%) of the cases. This difference was significant (p < 0.01). Fetal breathing movements (FBM), as indicated by activity of the posterior cricoarytenoid muscle, changed in 134 (55%) of 243 contractures, the change being from active to the quiescent state in 115 (85%) of contractures. Diaphragmatic activity changed in 11 (61%) of 183 contractures, with a change from activity to quiescence occurring in 100 instances (90%). Changes in tracheal pressure were associated with an altered state of FBM in 190 (61%) of 314 contractures, and the change was from the presence of FBM to absence of them in 178 (94%) of the changes. In all three of these indicators of FBM, the change from breathing activity to quiescence was statistically significant (p < 0.01).

Animals↗

Low serum-vitamin-A and subsequent risk of cancer. Preliminary results of a prospective study.

In a prospective study of about 16 000 men, serum samples were collected and stored. Vitamin-A (retinol) levels were later measured in the stored samples from the 86 men who were subsequently notified as having developed cancer and in the stored samples from 172 controls who did not develop cancer. Low retinol levels were associated with an increased risk of cancer. The association was independent of age, smoking habits, and serum-cholesterol level aand was greatest for men who developed lung cancer (mean retinol level 187 i.u./dl compared with 229 i.u./dl for the controls, p < 0.005). The risk of cancer at any site for men with retinol levels in the lowest quintile was 2.2 times greater than the risk for men with levels in the highest quintile (p < 0.025). These results suggest that measures taken to increase serum-retinol levels in man may lead to a reduction in cancer risk.

Adult↗

Angioneurotic oedema and urticaria following hydrocortisone--a further case.

It is still not commonly realized that immediate hypersensitivity reactions to hydrocortisone can occur. A rare case is reported which illustrates the need for caution when using this drug in atopic subjects. Ideally, parenteral hydrocortisone should only be used where facilities for resuscitation are available.

Adult↗

Inhaling habits among smokers of different types of cigarette.

Inhaling habits were studied in 1316 men who freely smoked their usual brands of cigarette. An index of inhaling was calculated for each person by dividing the estimated increase in carboxyhaemoglobin level from a standard number of cigarettes by the carbon monoxide yield of the cigarette smoked. Smokers of ventilated filter cigarettes inhaled 82% more than smokers of plain cigarettes (p less than 0.001) and those who smoked unventilated filter cigarettes inhaled 36% more (p less than 0.001). Cigarette consumption was similar among smokers of each type of cigarette. Assuming that the intake of tar and nicotine is proportional to the inhaling index, the intake in either group of filter cigarette smokers would have been less than that in plain cigarette smokers. Among smokers of unventilated cigarettes, however, the intake would not have been much less.

Adult↗

High-density lipoprotein and coronary risk factors in normal men.

Serum high-density-lipoprotein cholesterol (H.D.L.) was measured in 2568 men attending a screening centre and registered with a medical practitioner in Great Britain. Serum-total-cholesterol (T.C.), serum-triglyceride, serum-glucose, systolic and diastolic blood-pressures, electrocardiogram, chest X-ray, height, weight, cigarette and alcohol history, and a brief assessment of physical activity were also recorded. H.D.L. was inversely related to cigarette-smoking, relative weight, and serum-triglyceride level, and directly related to physical activity, total-cholesterol level, and alcohol consumption. The ratio of H.D.L. to T.C. (H.D.L./T.C.) showed similar significant relationships to the above variables (except that the ratio was negatively correlated with T.C.). In addition the ratio was inversely related to age. These relationships were independent of the other measured variables. Both the H.D.L. and H.D.L./T.C. were inversely related to coronary risk rating. It is suggested that, despite methodological problems, H.D.L. is a useful biochemical measurement to add to a coronary risk profile.

Adult↗

Executive screening.

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Ambulatory Care Facilities↗

Plasma, apolipoprotein, A-I and A-II levels in hyperlipidemia.

Some of the component moieties of high density lipoproteins (HDL) were analyzed in normal subjects and in patients with hyperlipidemia. Apoproteins A-I and A-II were quantified by radioimmunoassay, HDL cholesterol and triglycerides were assessed on heparin-MnCl2 supernates of fasting plasmas. We found that HDL is enriched in triglycerides in all forms of hyperlipidemia, while the proportion of ApoA-II is unaltered and the proportion of ApoA-I is decreased. Thus, the composition of HDL is altered in hupertirglyceridemia. The molecular associations of ApoA-I and ApoA-II in plasma were also examined by assaying the apoprotein contents of plasma fractions prepared by ultracentrifugation and by gel filtration column chromatograpy. The ApoA-I contents of d smaller than 1.063 fraction increased in hyperlipidemia from smaller than 0.5% to approximately 2%, but the ApoA-I contents of the d greater than 1.21 fraction remained at less than 12% of total plasmas with triglyceride levels smaller than 1500 mg/dl. d greater than 1.21 ApoA-I rose to 23% in one plasma with a triglyceride level of greater than 1700 mg/dl. On column chromatography, ApoA-I eluted with the lipoproteins and also in a fraction whose molecular weight (MW) appeared to be approximately 50,000 daltons. The proportion of plasma ApoA-I which eluted in the 50,000 MW peak was positively correlated with plasma triglyceride levels, but at triglyceride levels of less than 1500 mg/dl, less than 20% of ApoA-I was in the 50,000 MW peak. Between levels of approximately 2000 and 12,000 mg/dl, the percentage "50,000 M.W. ApoA-1" was 20-25%. The ApoA-II contents of d smaller than 1.063 fractions were also increased in hyperlipidemia, but greater than 95% of ApoA-II was found in the HDL fractions in both normal and hyperlipidemic plasma both by column chromatography and ultracentrifugation. Thus, the molecular association of ApoA-I appears to be altered in hyperlipidemia.

Apolipoproteins↗