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Biomedical subjects

T Gordon

Publications and source records attributed to T Gordon.

At least 217 records · Page 12Linked to original sources
PubMed1981

Comparison of methods for diagnosing angina pectoris: the Honolulu heart study.

Data from the Honolulu Heart Study suggest that the examining physician's clinical diagnosis, based on questioning the subject about chest pain, was more sensitive than the Rose questionnaire in detecting angina pectoris in a population of Japanese men. The 2 methods appear equally specific for coronary heart disease.

Aged↗
PubMed1981

Serum cholesterol and mortality: the Yugoslavia Cardiovascular Disease Study.

The relationship of level of baseline serum cholesterol to the seven-year incidence of death from all causes and from specific causes was examined in a cohort of 11,121 Yugoslav males aged 35--62 years at the time of their initial examination (1964--1965). Serum cholesterol was negatively related to mortality, i.e., those with a lower cholesterol experienced a higher mortality than those with a higher cholesterol. The negative relationship was significant (as assessed by logistic regression) and remained significant after adjusting for obesity, systolic blood pressure, cigarette smoking, age, history of intestinal parasitism, and socioeconomic status (as measured by years of education). The negative association of serum cholesterol and subsequent mortality appeared to be due to the relationship of cholesterol to deaths due to cancer and to deaths due to respiratory disease (tuberculosis and cor pulmonale). The cancer death-serum cholesterol relationship was not statistically significant but the respiratory disease death-serum cholesterol relationship was. Serum cholesterol, as expected, was positively related to the incidence of coronary heart disease death.

Adult↗
PubMed1981

The influence of innervation on differentiating tonic and twitch muscle fibres of the chicken.

1. The anterior (ALD) and posterior (PLD) latissimus dorsi muscles of adult chickens were denervated by section of their motor nerves. Four weeks later the contractile and membrane properties of these muscles were studied in vitro at room temperature.2. Although the time course of the PLD muscle twitch was slightly prolonged, the qualitative difference in contractile characteristics of the slow ALD and the fast PLD muscles was maintained after denervation.3. The difference in the passive membrane characteristics of the ALD and PLD muscle fibres was not lost after denervation, although the membrane resistance (R(m)) and space constant (lambda) of the denervated muscles fell. The membrane resistance, space (lambda) and time (tau(m)) constants of the ALD muscle remained significantly greater than for the PLD muscle fibres. The absolute values of tau(m) in both muscles increased, implying that in the case of the ALD the membrane capacitance (C(m)) was increased above normal after denervation. This is discussed in terms of the ultrastructural changes in this muscle after denervation.4. The ALD muscle was cut into small pieces and replaced in the bed of the PLD muscle, which in turn was minced and placed into the bed of the ALD muscle. These muscles regenerated and became reinnervated by the PLD and ALD nerves respectively. They aligned themselves in the muscle bed and adopted the former shape of the muscle that they replaced. The passive cable properties of the regenerated ALD muscle fibres innervated by the PLD nerve resembled the control PLD fibres and the regenerated PLD fibres reinnervated by the ALD nerve resembled those of the control ALD. Regenerated ALD and PLD reinnervated by their own nerves had contractile and membrane properties similar to those of control muscles.5. The results show that the fundamental differences, between slow and fast muscles once established, persist even when they are deprived of their innervation. The properties of developing muscle fibres however are determined by the motor nerves even in the adult animal.

Animals↗
PubMed1981

Classifying sensory patterns and their effects on locomotion and tremor.

Methods are described for analyzing the patterns of sensory activity in peripheral nerves during unrestrained behaviour. In locomotion, nerves supplying ankle extensors and flexors typically show two bursts of sensory activity per step cycle. Variations in sensory input may be important in modulating the ongoing oscillation. Altered sensory input may also change the phase of an ongoing oscillation (as in human essential tremor) or may only have a transient reflex effect (as in Parkinsonian tremor). Various types of interactions can be analyzed using a model of the peripheral neuromuscular system and its central connections. In general, the following categories are suggested for sensory actions on neural oscillations: (1) modulation of (a) the amplitude or (b) the frequency; (2) resetting (i.e., a maintained change in the timing of an oscillation without changes in frequency); (3) repatterning an oscillation (a) over several cycles (e.g., gait changes in locomotion) or (b) within a cycle or two (e.g., the stumble corrective reaction); and (4) gating an oscillation on or off.

Animals↗
PubMed1981

Diet and its relation to coronary heart disease and death in three populations.

Baseline 24-hour dietary recalls from 16,349 men ages 45-64 years who had no evidence of coronary heart disease (CHD) were obtained in three prospective studies: the Framingham Study (859 men), the Honolulu Heart Study (7272 men) and the Puerto Rico Heart Health Program (8218 men). These men were followed for up to 6 years for the first appearance of CHD or death. Men who had a greater caloric intake or a greater caloric intake per kilogram of body weight were less likely to develop CHD manifest as myocardial infarction (MI) or CHD death, even though men of greater weight were more likely to develop CHD. This may reflect the benefit of greater physical activity. Men who consumed more alcohol were less likely to develop CHD, but more likely to die of causes other than CHD, particularly in the Honolulu study. In the Honolulu and Puerto Rico studies, but not in the Framingham study, men who consumed more starch were less likely to develop MI or CHD death. There was an inverse relation between starch intake and serum cholesterol, but it was too weak to explain fully the inverse starch-CHD association. There was also no evidence that the inverse relation between starch intake and incidence of CHD in the Honolulu and Puerto Rico studies was an indirect result of differences in fat intake. While the findings suggest additional areas for research, none of them would lead to an alteration of currently recommended preventive diets that emphasize lowering fat intake, because in isocaloric diets the logical way to balance a decreased fat intake is to increase the consumption of foods containing starch.

Adult↗
PubMed1981

Alcohol and high-density lipoprotein cholesterol.

Associations between alcohol intake and levels of high-density lipoprotein (HDL) cholesterol were examined in 2473 men and 1530 women seen as part of the random sample at visit 2 of the Lipid Research Clinics Prevalence Study. More men than women reported alcohol intake. The alcoholic beverage preference differed by age and sex. The levels of HDL cholesterol were higher in drinkers than in nondrinkers. The statistically significant associations varied somewhat by age; however, the average correlation coefficient was 0.21 for men and 0.25 for women. HDL cholesterol levels were lower in those who reported never drinking alcohol than in occasional drinkers.

Adult↗
PubMed1981

Lipoproteins, cardiovascular disease, and death. The Framingham study.

Based on six years of follow-up evaluations of the Framingham, Mass, men and women aged 49 to 82 years, it was found that a low-density lipoprotein (LDL) cholesterol concentration was associated with a low incidence of coronary heart disease (CHD) risk but with a statistically significant excess of stroke incidence in women and of deaths from non-CHD causes in both sexes. There was no suggestion that an elevated HDL cholesterol level was associated with an excess incidence of any of the cardiovascular end points considered or of death. An inverse relation of high-density lipoprotein (HDL) cholesterol level with CHD and its major consequences, CHD death and congestive heart failure, was observed. Triglyceride determinations seem to add little information respecting cardiovascular risk to that elicited from HDL and LDL cholesterol and other known cardiovascular risk factors. While the relation of HDL and LDL cholesterol with CHD is paralleled by findings from a variety of sources, the inverse relation of LDL cholesterol with stroke in women and with death from non-CHD causes requires additional confirmation and exploration.

Aged↗
PubMed1980

Body build and mortality. The Framingham study.

Results of the Framingham study are compared with those of the 1959 Build and Blood Pressure Study (BBPS) using the same definitions of body build and using similar follow-up periods for mortality. Findings of the Framingham study do not accord with the insurance experience of that comprises the BBPS. With minor exceptions the insurance experience demonstrates that the greater the relative weight, the greater the risk of death. The unselected population sample of the Framingham study shows minimum mortality around the average weight with increased mortality for persons weighing less or more than average. The higher proportion of lean persons who smoke does not account for the excess mortality in the leanest group. These study differences raise questions on the current standards of ideal weight used for the American population.

Blood Pressure↗
PubMed1980

Frequency of alcohol consumption and morbidity and mortality: The Yugoslavia Cardiovascular Disease Study.

The association of frequency of alcohol consumption with the seven-year incidence of coronary heart-disease and with mortality both from all causes and from specific causes was examined in a cohort of 11 121 Yugoslav males aged 35-62 at the time of their initial examination. Consumption of alcohol seemed to be inversely related to incidence of coronary heart-disease morbidity and mortality, but not to risk of dying. Those consuming alcoholic beverages most frequently were at increased risk of death from stroke and accidents or violence. The frequency of alcohol consumption was associated with high blood-pressure and serum cholesterol levels. The associations with coronary heart disease and death from all causes could not be fully explained by these covariates.

Accidents↗
PubMed1980

Alcohol and mortality: the Honolulu Heart Study.

It has been shown previously that coronary heart disease was less likely to develop in Japanese men in Honolulu who drank alcoholic beverages than in those who abstained, and that the more they drank (up to about 60 ml/day of ethanol) the lower the risk. In this report on the same men, it is shown that the same sort of relation holds for mortality from coronary heart disease but that the reverse is true for death from cancer and from stroke. Men who drank were more likely to die from these causes than those who abstained, and the more they drank the greater the risk of death. Men who drank relatively large amounts were more likely to die from cirrhosis of the liver than other men. The resultant curve for total mortality is u-shaped, the lowest risk being for men who consumed from 1 to 10 ml/day of ethanol. Even at that low level of consumption, however, the risk of death from cancer or stroke was greater than it was for nondrinkers. In short, for this population of Japanese men, alcohol consumption appears to have some benefits and some hazards with regard to mortality, and the benefit or hazard depends on which cause of death is being considered.

Aged↗
PubMed1980

Effect of ozone on respiratory response of guinea pigs to histamine.

The effect of preexposure to ozone on the respiratory response to histamine was studied. The Amdur-Mead technique was used to measure respiratory mechanics in Charles River Hartley guinea pigs. Groups of animals were exposed for 1 h to filtered control air or ozone. Control measurements were made 1 1/2 h after exposure, followed by sc injection of 0.125 mg/kg histamine dihydrochloride. Respiratory measurements were continued at 2-min intervals for 16 min, at which time resistance and compliance had returned to control values. The 2-h interval between exposure and injection and the 0.125 mg/kg histamine were the optimum time interval and dose, respectively, as determined by appropriate time-response and dose-response studies. Although control values did not differ between air-exposed and ozone-exposed animals, animals preexposed to 0.1, 0.2, 0.4, and 0.8 ppm ozone had increases in resistance of 111, 110, 93, and 97% after histamine administration, compared to the air-exposed animals, which had increases of 86, 86, 67, and 46%, respectively. Whereas the only significant difference in resistance between air and ozone animals was at the 0.8-ppm level (p less than 0.05), significant differences in compliance changes were found at all levels of ozone exposure. Ozone animals had compliance decreases of 40, 45, 46, and 46% after histamine injection, while their respective air controls decreased 24, 24, 27, and 31%. Exposures to ozone of 0.2 ppm for 4 h and 0.4 ppm for 2 h provided doses equal to that of 0.8 ppm for 1 h, yet no significant dose-time relationship was found. Lingering sensitivity to pharmacologically active agents is a subtle but important manifestation of ozone toxicity.

Airway Resistance↗
PubMed1980

Long-term effects of axotomy on neural activity during cat locomotion.

1. Neural activity was recorded from cats during locomotion on a treadmill using electrodes in Silastic cuffs placed around the sciatic nerve and the lateral gastrocnemius-soleus, medial gastrocnemius, common peroneal and tibial nerve branches. Each branch gave characteristic patterns of activity which were studied before and after it was cut distal to the recording cuffs. Sensory and motor components were separated and measured using cross-correlation techniques. The amplitude of the cross-correlation peaks was compared with the amplitude of compound action potentials evoked by electrical stimulation and recorded from the same sites in the anaesthetized animal. 2. Sensory activity declined rapidly following axotomy and did not recover unless reinnervation occurred. Sensory activity even 5 months after nerve section and resuture had recovered to only a fraction of the control values. This reduction is attributed to a decline in the evoked compound potentials and to many fibres being unsuccessful in regenerating to appropriate sensory organs. 3. Motor activity declined more than could be accounted for by a decline in evoked potentials over the first month after axotomy. The extra reduction represents a decline in the number of impulses generated by alpha-motoneurones after axotomy. If regeneration was permitted, motor activity recovered to higher levels than did the evoked potentials for the whole nerve. Even if regeneration was prevented by nerve ligation, motoneurones continued to generate activity at a stable level over a period of months during which whole nerve compound potentials continued to decline. 4. The modulation of motor activity in ligated nerves during the step cycle was still appropriate to the required movement. Thus, activity recorded from severed nerves in human amputees may be useful in controlling powered artificial limbs. The persistence of motor activity may be responsible for the lesser degree of atrophy found in motor fibres than in sensory fibres following ligation (Hoffer, Stein & Gordon, 1979b).

Action Potentials↗
PubMed1980

Labile hypertension: a faulty concept? The Framingham study.

Labile blood pressure elevation is believed to have less clinical significance than "fixed hypertension." This assertion was examined in the Framingham cohort of 5209 men and women followed for 20 years for the development of cardiovascular events in relation to three routinely measured blood pressures at each of 10 biennial examinations. Variability of pressure judged from the standard deviation about the mean of three pressures was not a consistent characteristic of subjects from one examination to the next (r = 0.07). Higher pressures were more labile than low ones, so that "fixed hypertensives" actually had more labile pressures than did so-called labile hypertensives. Lability, also increased with age. Labile hypertension, determined during a 1-hour period of observation, adds nothing to the ability of the mean blood pressure to predict cardiovascular disease. The mean, minimum and maximum of three pressures measured during an examination were equally efficient predictors of cardiovascular disease. In multivariate analysis, for any given average pressure, risk of cardiovascular events was unaffected by the degree of variability of the pressure. It is recommended that the average of a series of pressures be used to determine risk, preferably over more than one examination.

Adult↗