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Biomedical subjects

C H Kallman

Publications and source records attributed to C H Kallman.

At least 37 records · Page 2Linked to original sources
PubMed1982

Nifedipine in unstable angina: a double-blind, randomized trial.

We assessed the efficacy of adding nifedipine to the conventional treatment of unstable angina in 138 patients in a prospective, double-blind, randomized, placebo-controlled trial. There was no difference between the two groups in the dose of conventional antianginal medication or in age, prior myocardial infarction, ejection fraction, or other risk factors. Failure of medical treatment (defined as sudden death, myocardial infarction, or bypass surgery within four months) occurred in 43 of 70 patients given placebo and in 30 of 68 given nifedipine. Kaplan-Meier survival-curve analysis of the number and time dependence of treatment failures demonstrated a benefit of nifedipine over placebo (P = 0.03). The benefit was particularly marked in patients with ST-segment elevation during angina (P = 0.02). Side effects (transient hypotension or diarrhea) required withdrawal of the drug from four patients given nifedipine and from one given placebo. We conclude that the addition of nifedipine to conventional therapy is safe and effective in unstable angina.

Adult↗
PubMed1982

Carotid sinus baroreceptor reflex control of respiration.

We have studied the effect of the carotid sinus baroreceptor reflex on respiration in 10 vagotomized, spontaneously breathing, pentobarbital anesthetized dogs. The carotid body chemoreceptor reflex response was eliminated by surgically excluding the carotid bodies from the carotid sinus baroreceptor area. Steady state frequency, tidal volume, and minute ventilation were measured after 25 mm Hg step changes in intrasinus pressure between 50 and 200 mm Hg. Over this range, the step decreases in intrasinus pressure caused concomitant increases in mean arterial pressure from 86 to 182 mm Hg. All of the respiratory response curves were sigmoidal in shape. Decreasing intrasinus pressure from 200 to 50 mm Hg caused respiratory frequency to increase from 4.8 to 9.7/min, and tidal volume to decrease from 704 to 515 ml. The calculated total ventilation, however, increased from 3180 to 4530 ml/min. The time of inspiration decreased from 3.7 to 2.4 seconds, and the time of expiration decreased from 9.8 to 4.1 seconds. These ventilatory responses are shown to be baroreceptor reflex mediated, and not secondary to changes in arterial pressure. These findings indicate that not only does the carotid sinus baroreceptor reflex control arterial pressure, but it also simultaneously influences ventilation, through changes in both respiratory frequency and tidal volume.

Animals↗
PubMed1982

Early discharge following acute myocardial infarction. Long-term follow-up of randomized patients.

Long-term follow-up was obtained on 138 patients who participated in a prospective, randomized study comparing two weeks with three weeks of hospitalization following uncomplicated acute myocardial infarction. Follow-up information was available on 123 (89%) of all randomized patients. The mean follow-up period was 35 months for those patients who died and 99 months for those who survived. No differences were found between the two groups with respect to survival, cardiac-related deaths, frequency or severity of angina pectoris, subsequent myocardial infarction, incidence of congestive heart failure, number of ventricular aneurysms, or subsequent medical therapy. A significantly greater number of survivors in both groups stopped smoking and had a normal initial heart size than those who died. This long-term follow-up study further supports the conclusions of earlier short-term studies that two weeks of hospitalization is safe in patients with uncomplicated acute myocardial infarction.

Adult↗
PubMed1981

Determinants of growth among poor children: nutrient intake-achieved growth relationships.

Seven-day individual weighed dietary intakes and anthropometric measurements were determined in 123 children, 2 to 19 yr of age, from 26 poor families in Lima: each included one child who had been malnourished, six were adopting families. Heights and weights were converted to "ages" based on Boston reference data and local data, then to "quotients" as percentages of actual ages. Mineral and vitamin intakes were expressed as amounts per day and per 1000 kcal, calories and protein as percentages of FAO/WHO recommendations for age and height age and of modified recommendations based on size of Peruvian children. Regression analyses identified common sources of nutrients and greater dependence of intakes on body size than on age. Analysis of covariance for sex identified different nutrient-growth correlations. Polynomial regression analysis identified percentage protein from animal sources and percentage fat calories as having significant quadratic as well as linear correlations with achieved growth. In males, multiple regression analysis identified percentage protein from animal sources and beta-carotene intakes as strongly associated with achieved height and weight, and percentage fat calories as strongly associated with weight quotient/height quotient ratios. In females the correlations were not as strong, possibly because a significant percentage had reached the menarche some time before the survey and were probably no longer growing. Nevertheless, calorie intake, as a percentage of the recommendation for height age, was prominent in the regressions for height quotient and percentage fat calories in that for weight quotient. The very strong association of animal protein intake with male height, despite seemingly generous total protein intakes, is difficult to reconcile with current recommendations. The possible role of vitamin A (as beta-carotene) has potentially important implications for food policies.

Adolescent↗
PubMed1981

Determinants of growth among poor children: relation of nutrient intakes to expenditure for food.

The growth status and the nutrient intakes of 123 children from 26 urban poor families in Peru were related to per capita expenditure for food. Children from six better off families were taller and heavier (p less than 0.001), with no difference in weight for height. They had significantly higher calorie and total protein intakes (as percentage of recommended) and higher intakes of animal protein, fat, calcium, carotene, riboflavin, and vitamin C. When macronutrient intakes were expressed as percentages of recommended calorie intakes, correcting for age and relative size, all of the increase in total protein intake was due to animal protein, vegetable protein remaining constant. Almost all of the increase in adequacy of total calories was due to increasing fat intakes, relatively much less to carbohydrate, and this only among the poor families. In this population, as more money becomes available to purchase food, there is an increase in animal protein and fat intakes, over an almost constant vegetable protein and carbohydrate intake. There is a simultaneous increase in consumption of fruits and vegetables, accounting for increases in the carotene and vitamin C intakes.

Adolescent↗
PubMed1981

Effects of nitroglycerin on regional myocardial ischemia induced by atrial pacing in dogs.

The exact mechanism or mechanisms by which nitroglycerin exerts its beneficial effect on pacing-induced regional myocardial ischemia has not been ellucidated previously. In an open-chest, anesthetized canine preparation a fixed, flow limiting stenosis was applied to the left anterior descending (LAD) coronary artery and heart rate was increased by atrial pacing. Mass spectrometry was used to measure myocardial oxygen (PmO2) and carbon dioxide (PmCO2) tensions. Myocardial blood flow was measured by the radioactive microsphere technique. Application of the stenosis resulted in regional decreases in PmO2 and increases in PmCO2 of greater magnitude in the subendocardial than in the subepicardial layer. Atrial pacing resulted in a further decrease in PmO2 and increase in PmCO2 as well as a reduction in subendocardial blood flow. Nitroglycerin (TNG) infusion reduced mean arterial pressure 20 mm Hg, resulting in a 14 mm Hg reduction in PmCO2 in the more ischemic subendocardial layer (P less than 0.05). Myocardial blood flow decreased in all regions; however, the magnitude of this decrease was less in the ischemic region. Addition of aortic constriction abolished both the afterload and preload lowering effects of nitroglycerin but improved ischemic zone blood flow. These data demonstrate that nitroglycerin reduces the severity of pacing-induced regional myocardial ischemia primarily by reducing the determinants of myocardial oxygen demand. We found that when these effects are counteracted, improvement in myocardial oxygen supply becomes the dominant mechanism.

Animals↗
PubMed1981

The effect of right ventricular filling on the pressure-volume relationship of ejecting canine left ventricle.

Acute shifts in the pressure-volume relationship of the left ventricle occur under several conditions. One potential mechanism for this phenomenon is ventricular interdependence, that is, the influence of right ventricular filling on the left ventricle. This mechanism was studied in an isolated cross-circulated ejecting canine heart preparation with balloons sewn into both right and left ventricles and connected to volumetric chambers allowing continuous and accurate simultaneous measurement of right and left ventricular pressures and volume. Sets of left ventricular pressure-volume loops were obtained under a variety of right ventricular volumes. Experiments were repeated with and without the pericardium. Both diastole and systole were studied. We show that in the pericardium-free heart working over a normal range of volumes, the right ventricle exerts little influence on left ventricular pressure. With the pericardium present, there is a small but significant effect of right ventricular volume on left ventricular pressure during systole and diastole. Over a wider range of volumes imposed in the arrested heart, the right ventricle does influence left ventricular pressure even without the pericardium. Thus we have demonstrated that ventricular interdependence is not likely to lead to large acute pressure-volume shifts, either during diastole or systole, except in the presence of considerably above normal right ventricular volumes.

Animals↗
PubMed1980

The development of catecholaminergic innervation in chick spinal cord.

This combined biochemical and histofluorescent study of the embryonic chick was designed to investigate the temporal and spatial development of noradrenergic pathways in the spinal cord. The sequence of catecholaminergic innervation was analyzed by measuring the specific uptake of [3H]norepinephrine, the levels of endogenous norepinephrine, and the distribution of catecholamine histofluorescence. Uptake studies showed early axons present in all levels of spinal cord by 10 days incubation with subsequent increases of uptake activity appearing in a rostrocaudal fashion. Endogenous norepinephrine values were low until day 14, at which time transmitter levels began to increase, approaching hatched values on incubation day 17. Morphologic studies demonstrated catecholaminergic terminals first in the intermediate gray matter and later concentrated in the ventral and dorsal horns. These observations were interpreted to indicate that: (1) noradrenergic axons are an early descending supraspinal pathway; (2) arborization of this system occurs in a rostral-caudal sequence; and (3) monoaminergic uptake mechanisms develop prior to and independent of neurotransmitter synthesis and storage. The development of this noradrenergic system parallels alteration in spinal cord physiology and refinements in the motility of the embryo.

Animals↗
PubMed1980

Urban-rural differences in the growth of Peruvian children.

The growth characteristics of children from four villages in northern Peru were compared with those of poor urban children in the capital city, in whom short stature but generally satisfactory weight for height relationships after infancy had been demonstrated. Height for age and weight for age fell more rapidly during infancy in the rural than in the urban children of both sexes. Rural girls caught up with the urban girls in height during childhood but did not match them in weight until late adolescence. Their weight to height ratios were consistently lower after 1 year of age, most strikingly between 2 and 5 years of age, and did not approach or match those of the urban girls until adolescence. Rural boys did not catch up with the urban boys in height or weight (differences in height were not statistically significant between 6 and 10 years, however) and their ratios remained consistently lower until late adolescence, most strikingly in early childhood and during puberty. Such urban-rural and sex differences, if typical and current, might well call for very different remedial measures at different ages in each of the populations.

Adolescent↗
PubMed1979

Growth standards for poor urban children in nutrition studies.

In order to estimate the importance of a variety of environmental and dietary factors as determinants of growth in a group of 123 poor Peruvian urban children between 2 and 19 years old, we found it necessary to express anthropometric measurements in units that were not age- or sex-dependent. Height quotient and weight quotient for each child were calculated from height and weight ages derived from the 50th percentile of the Boston reference data for the appropriate sex. Only 5% of the children had heights above the Boston 50th percentile (height quotient greater than 100) and 18% had weights above the 50th percentile (weight quotient greater than 100), but 88% had weights that were appropriate or excessive for height (weight/height quotient greater than or equal to 1.00). Some CATch-up" gains in relative height and weight were apparent in preschool children but more impressive gains in both linear and ponderal growth, relative to the Boston data, were evident between 8 and 13.5 years in girls and 10 and 17 years in boys. When the same quotients were calculated for a much larger sample from the same socioceonomic level it seemed likely that this last peak was due to earlier puberty and sexual maturation, and that quotients derived from the Boston data would have different meanings at different ages, making them inappropriate for further statistical analysis. New quotients for the study population, derived from the larger Peruvian group, did not have sex- or age-dependent trends. Racial and regional differences in patterns of growth must be taken into account in the interpretation of anthropometric and nutritional data.

Adolescent↗
PubMed1979

Absence of increasing incidence of meningitis caused by Haemophilus influenza type b.

An epidemiologic survey of meningitis caused by Haemophilus influenzae type b in children aged zero to four years during an 11-year period (January 1965-December 1975) was conducted in the Baltimore, Maryland, metropolitan area to examine recent trends in the incidence of this disease. Cases of H. influenzae meningitis were identified at all 19 hospitals in the city and county of Baltimore and all 41 hospitals in the surrounding area. The population at risk (age, zero to four years) was estimated using yearly birth rates provided by the state of Maryland and U.S. Census information for 1960 and 1970. Yearly age-adjusted incidence was calculated; in contrast to previous studies, there was no significant increase in the annual incidence (range, 12-27; mean, 19.3/100,000 population at risk). Previous reports of recent increases in the incidence of meningitis caused by H. influenzae type b may be due to differences in study techniques.

Black People↗
PubMed1979

The effects of L-dopa on in vitro and in vivo calcitonin release from medullary thyroid carcinoma.

The in vivo and in vitro effects of the dopamine precursor L-dopa on basal and stimulated calcitonin release from medullary thyroid carcinoma have been studied. In six studies of five patients, including 7- to 8-h control and test periods, oral L-dopa depressed basal calcitonin secretion by an average of 35%; the peak effects occurred within 30 min of drug administration and lasted for as long as 4 h. In seven of eight patients with medullary thyroid carcinoma (three infused with calcium and five with pentagastrin), L-dopa inhibited to varying degrees peak levels of stimulated calcitonin release and total calcitonin secretion; basal calcitonin levels, where directly tested, also again generally fell after L-dopa by an average of 50%. In a short term organ culture system using medullary thyroid carcinoma tissues, calcitonin secretion into the medium was linear with time for 2 h and could be stimulated by dibutyryl cAMP and pentagastrin. L-Dopa, in concentrations from 0.5--3.0 mM, inhibited basal calcitonin secretion (ranging from 25--55%). Addition of the L-dopa decarboxylase inhibitor, alpha-methyldopa, abolished the inhibitory effects of L-dopa. Another L-dopa decarboxylase inhibitor, carbidopa, stimulated calcitonin secretion in vitro; this effect may be independent of the L-dopa decarboxylase-inhibiting properties of this drug since alpha-methyldopa alone did not stimulate calcitonin secretion. It is concluded that the amine precursor L-dopa inhibits calcitonin release in patients with medullary thyroid carcinoma; the in vitro studies suggest that a portion of this effect may involve direct metabolism of L-dopa to dopamine in the tumor tissue itself. The importance of considering the uptake of amine precursors and the subsequent metabolism of these compounds as a modulating site for peptide hormone release from peripheral endocrine tissues is stressed.

Calcitonin↗
PubMed1975

Long-time observations on the Blalock-Taussig operation VIII. 20 to 28 year follow-up on patients with a tetralogy of Fallot.

This study extends our previous observation on patients with a tetralogy of Fallot, operated on by the late Dr; Alfred Blalock and his associates between 1945 and 1951, from a 15 year follow-up to 20 years and assesses the final status of these patients 20 to 28 years after their first operation. This study is mainly concerned with the 432 patients known to be alive at the beginning of the 15th postoperative year. At the beginning of the 20th year, 376 patients were alive, 24 had died, 32 had been lost to follow-up. Review of the final status of those 432 patients showed that 169 had no further cardiac surgery after their initial operation, 36 had further palliative surgery, and 227 had total correction. Thirty-seven percent of the first group, and 79.3% of those with total correction were doing well. These two groups, however, are not comparable. Approximately 250 patients have married; 161 have one or more children. Thirty-five percent have graduated from college and 68.7% are earning substantial incomes. The high scholastic achievement of many of these patients is strong evidence that low oxygen saturation of arterial blood is not a prime cause of mental retardation. The occupations of the patients indicate that the quality of their lives is extremely good and that a cardiac handicap in childhood does not preclude success in adult life. Approximately 69% of these patients have repaid in taxes the cost to society of their rehabilitation.

Educational Status↗