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Biomedical subjects

T Gordon

Publications and source records attributed to T Gordon.

At least 199 records · Page 11Linked to original sources
PubMed1984

Some difficulties inherent in the interpretation of dietary data from free-living populations.

Isocaloric adjustments of diet in metabolic experiments tend to induce negative correlations. In free-living populations, on the other hand, the absolute amounts of major nutrients consumed are positively correlated with total calorie intake and with each other. In general, these positive correlations are fairly strong. Relative amounts of nutrients consumed tend to be weakly and negatively correlated with total calories and each other. Because of these intercorrelations conclusions drawn from cross-sectional population data are ambiguous, at best, and misleading, at worst. Beyond that, the correlation between the intakes of specific nutrients with total calorie intake introduces the possibility that dietary variables may to some degree be surrogates of some nondietary variables; in particular, of physical activity. Unless the questions being asked in population studies are precisely formulated, with a careful consideration of the biological issues and the statistical limitations, biased conclusions are likely to result.

Adult↗
PubMed1984

Drinking and mortality. The Framingham Study.

Drinking and subsequent mortality were examined in a cohort of 5,209 men and women from Framingham, Massachusetts. Alcohol histories were obtained at the second biennial examination (1950-1954) from 2,106 men and 2,641 women. Of this group, 646 men and 521 women died in the next 22 years. Unlike what is reported from most other prospective studies, men who drank had lower mortality than men who did not, the lowest mortality being for light drinkers. Even men drinking 60 ounces of alcohol per month or more had no greater mortality than nondrinkers. Drinking by women was unrelated to subsequent mortality. For most alcohol-related causes, there were too few deaths to analyze. Liver cirrhosis, however, accounted for 24 deaths. Although these were related to alcohol use, more than half of the persons dying from this cause reported drinking less than 60 ounces of alcohol per month at baseline. There was, however, a very strong association of heavy alcohol consumption with stomach cancer, but not with any other cancer.

Adult↗
PubMed1984

Ozone-induced airway hyperreactivity in the guinea pig.

The predominant airway site and mechanism underlying ozone (O3)-induced respiratory hyperresponsiveness was examined in anesthetized guinea pigs and in vitro tissue preparations. Animals exposed to 1.0 or 1.2 ppm O3 (1 h) demonstrated an enhanced airway response to subcutaneous histamine compared with air-exposed animals. The anatomic site of hyperresponsiveness most likely did not involve the parenchyma, since quasi-static deflationary pulmonary compliance was decreased to a similar extent by histamine in air- and O3-preexposed animals. In contrast, the conducting airways were probably involved as changes in pulmonary resistance elicited by subcutaneous histamine were greater in O3- than in air-exposed animals. Neither atropine nor vagotomy abolished this enhanced responsiveness induced by O3. Although vagal interruption did not alter responsiveness, O3-exposed animals demonstrated greater respiratory responses to efferent electrical stimulation of the vagi than air-exposed animals. This suggests the site of hyperresponsiveness may be located distal to the site of efferent stimulation, possibly in the smooth muscle itself or in its microenvironment.

Acid-Base Equilibrium↗
PubMed1984

Tuberculous meningitis presenting as an obstructive myelopathy. Case report.

Subacute paraplegia progressing over 3 months due to spinal cord compression was the presenting symptom of tuberculous meningitis in this patient with a normal chest x-ray film and no radiological or autopsy evidence of Pott's vertebral tuberculosis. The obstructive myelopathy was the result of proliferative granulomatous meningitis. A review of the literature indicates that this is a very unusual presentation of tuberculous meningitis.

Aged↗
PubMed1983

Drinking habits and death. The Yugoslavia cardiovascular disease study.

In a prospective study of more than 10000 Yugoslav men it was found that consumption of alcoholic beverages was inversely related to non-sudden death from coronary heart disease (CHD) and positively related to death from trauma. The consequence was an apparently U-shaped relation between alcohol consumption and death, the lowest mortality being among moderate drinkers. Excess mortality from trauma was evident only among men under 55 and only for those who reported at entry to the study that they had been drunk during the preceding week. Alcohol consumption as reported at entry was unrelated to subsequent mortality from liver cirrhosis or any form of cancer. An enlarged liver, however, was associated with higher death rates for liver cirrhosis. This raises the possibility that some of the men were heavy drinkers preceding their entry to the study but were no longer drinking heavily at the time of entry. Enlarged liver, however, was also related to hypertension and to chronic obstructive pulmonary disease and thus was not a specific indicator of alcohol abuse in this population. Recent drunkenness but not frequency of drinking was related to death from trauma and liver cirrhosis and to sudden CHD death. In short, both the pattern of drinking and the usual level of alcohol consumption appear to be related to mortality in this population.

Adult↗
PubMed1983

Drinking and its relation to smoking, BP, blood lipids, and uric acid. The Framingham study.

Drinking habits and other characteristics were observed for 20 years in a cohort of 5,209 Framingham, Mass, men and women. During this period the average amount of alcohol consumed rose 63%. The percent increase was greater for women than men and greater for younger persons than older. Serum uric acid and phospholipid concentrations were higher at higher levels of alcohol consumption. Lipoprotein levels of 0 to 12 and 100 to 400 Svedberg units were positively associated with alcohol consumption in men but negatively associated with alcohol consumption in women. Blood pressure was higher in nondrinkers than light drinkers, but among drinkers BPs were higher at higher consumption levels. While cigarette smokers had lower BPs than nonsmokers, this seemed to be due to their lower weight. Persons who increased their alcohol consumption during follow-up had a small mean increase in serum phospholipid and uric acid levels, BP, and weight relative to the average changes for these variables.

Adult↗
PubMed1982

Temperature dependence of mammalian muscle contractions and ATPase activities.

Isolated rat and mouse extensor digitorum longus (EDL) and soleus muscles were studied under isometric and isotonic conditions at temperatures from approximately 8 degrees -38 degrees C. The rate constant for the exponential rise of tension during an isometric tetanus had a Q10 of approximately 2.5 for all muscles (corresponding to an enthalpy of activation, delta H = 66 kJ/mol, if the rate was determined by a single chemical reaction). The half-contraction time, contraction time, and maximum rate of rise for tension in an isometric twitch and the maximum shortening velocity in an isotonic contraction all had a similar temperature dependence (i.e., delta H approximately 66 kJ/mol). The Mg++ ATPase rates of myofibrils prepared from rat EDL and soleus muscles had a steeper temperature dependence (delta H = 130 kJ/mol), but absolute rates at 20 degrees C were lower than the rate of rise of tension. This suggests that the Mg++ ATPase cycle rate is not limiting for force generation. A substantial fraction of cross-bridges may exist in a resting state that converts to the force-producing state at a rate faster than required to complete the cycle and repopulate the resting state. The temperature dependence for the rate constant of the exponential decay of tension during an isometric twitch or short tetanus (and the half-fall time of a twitch) had a break point at approximately 20 degrees C, with apparent enthalpy values of delta H = 117 kJ/mol below 20 degrees C and delta H = 70 kJ/mol above 20 degrees C. The break point and the values of delta H at high and low temperatures agree closely with published values for the delta H of the sarcoplasmic reticulum (SR) Ca++ ATPase. Thus, the temperature dependence for the relaxation rate of a twitch or a short tetanus is consistent with that for the reabsorption rate of Ca++ into the SR.

Adenosine Triphosphatases↗
PubMed1982

Drinking habits and other characteristics: the Yugoslavia Cardiovascular Disease Study.

In two large general populations of Yugoslav men from Tuzia, Bosnia, and Remetinec, Croatia, examined in 1964-1965, it was found that a greater alcohol consumption was accompanied by higher blood pressures, higher pulse rates, and higher concentrations of serum cholesterol and hematocrit. A greater consumption was also associated with an enlarged liver, as well as a higher prevalence rate of chronic bronchitis and thrombophlebitis. All these were statistically significant even after allowing for differences in cigarette smoking and demographic characteristics. Pulse rate, liver size, and varices appear to be specifically associated with a history of episodes of drunkenness. There were significant differences in drinking habits by place of residence, religious background, years of schooling, and kind of work. These were allowed for in evaluating the relationship of drinking to other characteristics. Two anomalous findings were low prevalence rates for diabetes and gastritis among those drinking most frequently.

Adult↗
PubMed1982

Drinking habits and coronary heart disease: the Yugoslavia cardiovascular disease study.

In a prospective study of more than 10,000 Yugoslav men residing in Bosnia and Croatia, who were first examined in 1964--1965, consumption of alcoholic beverages was related inversely to the subsequent appearance of coronary heart disease clinically manifest as myocardial infarction or nonsudden coronary heart disease death. Consumption of alcoholic beverages was not so related to sudden cardiac death. Men who drank most frequently had half the subsequent incidence of overall coronary heart disease as men who seldom or never drank. This finding was true for urban residents only. Serum cholesterol and Quetelet index were also related to coronary heart disease in urban areas but not in rural areas. The inverse relation of alcohol consumption to coronary heart disease incidence was statistically significant even after taking into account differences in blood pressure, serum cholesterol levels, cigarette smoking and other variables. The apparent absence of protection against sudden death may be due to chance or it may reflect the deleterious effects of high alcohol consumption on the myocardial cells and increased vulnerability to lethal arrhythmias in an especially lean population. There is, in fact, a specific association of recent drunkenness with sudden death in this population. Conceivably, the acute effect of heavy drinking may be a dominant factor in the incidence of sudden death for this population.

Adult↗
PubMed1982

Time course and extent of recovery in reinnervated motor units of cat triceps surae muscles.

1. Nerve and muscle properties were studied in single motor units of triceps surae muscles in the cat using chronic recording techniques and intramuscular microstimulation. Recordings were made before and at intervals up to 18 months after a nerve was sectioned and sutured either to its distal stump (nerve-nerve suture) or to a muscle directly (nerve-muscle suture). Thus, each nerve and muscle served as its own control for recovery after reinnervation.2. Following a delay all muscles recovered their preoperative tension after nerve-nerve suture with a single exponential having a time constant of 1-2 months. Only half the muscles recovered their preoperative tensions after nerve-muscle sutures. Muscles which did not recover fully also had a slower time course of recovery.3. The estimated number of motor units did not increase significantly later than 2 months after nerve section and suture. Further recovery of muscle tension is due to increased unit tension, rather than increasing numbers of reinnervated motor units. Unit tension recovered completely in all muscles, but did not become enlarged, even when muscles apparently remained partially denervated.4. The latency of compound nerve potentials often recovered completely, although the amplitude of the potential remained depressed. Single motor axonal potentials recovered to control levels after reinnervation of muscle with a time constant similar to that for the recovery of motor unit tension. Therefore, two distinct populations of motor axons contribute to the compound potential: reinnervating axons whose size recovers fully, and disconnected axons which remain atrophic. Incomplete recovery of the compound potential amplitude mainly results from a failure of all axons to remake peripheral connexions.5. Thus, formation of functional nerve-muscle connexions completely reverses the effects of axotomy on nerve and muscle. Reinnervated motor units recovered their preoperative size, whether or not much of the muscle remained denervated.

Action Potentials↗
PubMed1981

Studies on the morphology of human uric acid stones.

Human uric acid acid renal stones are easily distinguished from other urinary calculi by their globular or spherical shape, their colour and their hardness. Investigations of uric acid crystals grown in the presence of a variety of pigments indicate that a disordered layer structure of the uric acid dihydrate is responsible for the colour of such crystals, caused by the inclusion of pigment molecules into the crystal lattice. This in turn may help to explain the other special properties of uric acid stones.

Crystallography↗