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Biomedical subjects

A H Goodman

Publications and source records attributed to A H Goodman.

At least 19 recordsLinked to original sources
PubMed2000

Why genes don't count (for racial differences in health).

There is a paradoxical relationship between "race" and genetics. Whereas genetic data were first used to prove the validity of race, since the early 1970s they have been used to illustrate the invalidity of biological races. Indeed, race does not account for human genetic variation, which is continuous, complexly structured, constantly changing, and predominantly within "races." Despite the disproof of race-as-biology, genetic variation continues to be used to explain racial differences. Such explanations require the acceptance of 2 disproved assumptions: that genetic variation explains variation in disease and that genetic variation explains racial variation in disease. While the former is a form of geneticization, the notion that genes are the primary determinants of biology and behavior, the latter represents a form of racialization, an exaggeration of the salience of race. Using race as a proxy for genetic differences limits understandings of the complex interactions among political-economic processes, lived experiences, and human biologies. By moving beyond studies of racialized genetics, we can clarify the processes by which varied and interwoven forms of racialization and racism affect individuals "under the skin."

Bias↗
PubMed1993

Response of bone and enamel formation to nutritional supplementation and morbidity among malnourished Guatemalan children.

The effects of changes in nutritional and health status upon bone and enamel development are examined in a sample of 63 rural Guatemalan children (24 females, 39 males). The number of ossified hand-wrist centers at 3 years and the number of linear enamel hypoplasias (LEH) in approximately 0-3 year zones of developing teeth were used to monitor the response of bone mineralization and enamel matrix formation to illness and nutritional supplementation. Numbers of ossified centers and LEH were compared across sex, supplementation, and morbidity groups. Enamel matrix secretion responded positively to increased supplementation. Children who received less than 34.25 kcal/day in supplement had more LEH than those who received more supplement. No differences in ossification status were found between supplementation groups. These data suggest that enamel formation may be more sensitive to changes in nutritional status than is bone mineralization. Disruptions of bone and enamel formation were both associated with frequent illness. Children who were ill more than 3.6% of the time had more LEH and fewer ossified hand-wrist centers than children who were less frequently ill. Conclusions regarding relative environmental sensitivity must take into account the specific aspects of dental and skeletal development examined.

Age Factors↗
PubMed1991

Nutritional supplementation and the development of linear enamel hypoplasias in children from Tezonteopan, Mexico.

The purpose of this study was to compare the effect of nutritional intake during tooth-crown formation on the subsequent development of linear enamel hypoplasias (LEHs) in Mexican nonsupplemented (control) adolescents (n = 42) and adolescents who had received daily nutritional supplements since birth (n = 42). The proportion of individuals with LEHs was nearly two-fold greater (74.4%; 95% CI 64.7-84.1%) in the control than in the supplemented group (39.5%; 95% CI 28.6-50.4%; chi 2 = 9.44; P = 0.001). Although the estimated peak age at formation, approximately 2-2.5 y, is similar in both groups, the proportion of early (before 1.5 y) and late (after 3.0 y) LEHs was greater in the control group. LEH was also more common in females and was associated with an increase in illness days and a decrease in growth velocity. Results of this study suggest that mild to moderate undernutrition during enamel formation is causally linked to the formation of LEHs.

Anthropometry↗
PubMed1989

Characterization of intact mesenteric lymphatic pump and its responsiveness to acute edemagenic stress.

The contractile properties of the mesenteric collecting lymphatics of the rat were analyzed under control conditions and during periods of enhanced lymph formation using in vivo microscopic techniques. Pressure and diameter were simultaneously monitored in microscopic collecting lymphatics, and lymphatic pump function was analyzed in accordance with basic principles of cardiac mechanics. The lymphatic contractile cycle was divided into two phases of systole and four phases of diastole. Under control conditions, lymphatics contracted with a frequency of 6.4 +/- 0.61 beats/min and ejected approximately 67% of their end-diastolic volume. Ten minutes after the rate of lymph formation was elevated by plasma dilution, end-diastolic diameter, contraction frequency, ejection fraction, and stroke volume increased. Pressure in the lymphatic network became less pulsatile in high lymph flow states. Contractility, an index of inotropic changes in lymphatic pump, was unaltered when lymph flow was increased by plasma dilution. Furthermore, the maximal shortening velocity of lymphatic smooth muscle did not change during periods of enhanced lymph flow. Thus it appears that passive increases in the rate of lymph formation exert few, if any, inotropic effects on the lymphatic pump. The augmented stroke volume and contraction frequency appear to result mainly from intrinsic stretch-dependent mechanisms set in motion by elevated preload. These data represent the first comprehensive characterization of both the flow-generating and muscle characteristics of intact collecting lymphatics and provide a basis for future studies on the physiological regulation of lymphatic contraction.

Animals↗
PubMed1989

Dental enamel hypoplasias in prehistoric populations.

Recent years have witnessed an impressive increase in research on enamel hypoplasias in archaeological populations. By reviewing a series of studies of enamel hypoplasias at Dickson Mounds, Illinois, North America (950-1300 A.D.), a prehistoric site involved in the transition from gathering-hunting to agriculture, this paper provides an illustration of this type of research. The location of linear hypoplasias on labial tooth surfaces of 111 adults was studied with a thin-tipped caliper, and this location was converted to an age at development. Most defects developed between two and four years of developmental age. Hypoplasias increased in prevalence from 45% in the pre-agriculture group to 80% in the agricultural group (p less than 0.01). The transition to agriculture occurred at a cost to infant and childhood health. Defects are associated with decreased longevity. Individuals with defects have a life expectancy of nearly ten years fewer than those without defects, suggesting that the development of a defect marks a significant and lasting health event. Enamel hypoplasias occur most frequently on anterior teeth, polar teeth in developmental fields, and the middle developmental thirds of teeth. Analysis of these data suggests that enamel may be differentially susceptible to growth disruption and that susceptibility varies both within and among teeth. The study of enamel defects at Dickson provides insights into the health and nutritional consequences of the economic change from hunting and gathering to agriculture. More generally, with the availability of teeth from genetically homogeneous populations, studies of enamel hypoplasias in prehistory should provide a useful complement to research on this condition in contemporary peoples.

Dental Enamel Hypoplasia↗
PubMed1988

Balloon dilatation of stenotic right ventricle-to-pulmonary artery conduits.

In seven children with obstructed right ventricle-to-pulmonary artery conduits, balloon dilatation (BD) was performed 10-58 months after insertion of the conduit. Average valve gradient was reduced from 69 to 32 mmHg. Obstruction at the conduit-branch pulmonary artery connection became apparent after dilatation of the valve; these distal stenoses also were dilated. It is concluded that the useful lifetime of a right ventricle (RV) to pulmonary artery (PA) conduit may be extended by BD of an obstructed biological valve and/or BD of a stenotic conduit-pulmonary artery anastomosis.

California↗
PubMed1988

Infestation in the dog by the paralysis tick, Ixodes holocyclus. 4. Cardiovascular effects.

To determine the extent and significance of changes in heart rate and rhythm noticed previously in dogs paralysed with Ixodes holocyclus, two studies were undertaken. In one the electrocardiogram was recorded at stages throughout the disease and the traces analysed for changes, while in the second a detailed study of the effect of Ixodes holocyclus on the cardiovascular system was undertaken. The electrocardiographic changes were extremely variable between stages and between dogs. Generally, if a dysrhythmia occurred in stages 1, 2 or 3 it tended to be sinus tachycardia, ventricular tachycardia or sinus arrest. In stage 4 sinus arrest, sinus bradycardia, or sinus or ventricular tachycardia were the prominent dysrhythmias, whereas in stage 5 sinus bradycardia predominated. Cardiovascular measurements indicated an increase in peripheral vascular resistance leading to a significant elevation in mean arterial pressure at all stages of the disease. Cardiac output was decreased significantly only at stage 2, although it was below the control measurements at all stages. Pulmonary arterial pressure was significantly elevated at stages 2, 3 and 4 due most probably to an increase in pulmonary vascular resistance. Myocardial contractility was not significantly changed throughout the disease. The changes observed in the electrocardiogram and the cardiovascular system in stages 1, 2 and 3 are unlikely to be due to hypoxia and could represent dysfunction of the autonomic nervous system. During stages 4 and 5 oxygen levels were below normal and the bradycardia seen terminally is almost certainly due to hypoxaemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Experience with Damus procedure.

Sixteen patients with complex cyanotic congenital heart disease underwent an operation involving the use of the aorta and the main pulmonary artery as the egress for systemic arterial blood flow (the Damus-Kaye-Stansell operation, modified as discussed). The indication for this approach was either preoperative aortic outlet obstruction or likelihood that the repair would produce such obstruction. A modification of the original technique is introduced that involves transection of both great arteries, anastomosis of the contiguous aortic and pulmonic walls, and connection of the distal aorta to the perimeter of the new (bivalved) great artery. Eleven of the 16 patients survived operation: six of six who underwent a concurrent Fontan operation, four of six who underwent a concurrent right-ventricle-to-pulmonary-artery-conduit procedure, and one of four who underwent a concurrent systemic-pulmonary shunt procedure. Postoperative status in the 11 survivors is good: one patient has a gradient from the left ventricle to the aorta, 10 of 11 have little or no aortic regurgitation, and the remaining patients have a normal physiological status. We conclude that the Damus procedure is a useful addition to the surgical armamentarium for treatment of certain types of cyanotic congenital heart disease.

Angiography↗
PubMed1988

Inotropic activity of digitoxigenin glucoside and related glycosides.

The cardiovascular effects of digitoxigenin glucoside and two derivatives, digitoxigenin glucoside tetraacetate and 4',6'-isopropylidene digitoxigenin glucoside were studied in pentobarbital-anaesthetized dogs. Digoxin (0.112 mumol/kg) and digitoxigenin glucoside (0.056 mumol/kg) produced similar increases in myocardial contractility, although digitoxigenin glucoside was faster in onset of action and had a shorter duration of action. Digitoxigenin glucoside caused a significantly greater increase in blood pressure than digoxin. Digitoxigenin glucoside tetraacetate (0.056 mumol/kg) and isopropylidene digitoxigenin glucoside (0.112 mumol/kg) also increased myocardial contractility. Time to peak effect and duration of action were similar to those of digitoxigenin glucoside. The tetraacetate derivative of digitoxigenin glucoside was less hypertensive than the parent compound. The results suggest that the rapid onset and short duration of effect are a function of the glucose moiety. The rapid onset and, what appears to be, a reduced tendency to accumulate may confer clinical potential for these analogues.

Animals↗
PubMed1987

Prevalence and age at development of enamel hypoplasias in Mexican children.

Enamel hypoplasias, deficiencies in enamel thickness resulting from disturbances during the secretory phase of enamel development, are generally believed to result from nonspecific metabolic and nutritional disruptions. However, data are scare on the prevalence and chronological distributions. of hypoplasias in populations experiencing mild to moderate malnutrition. The purpose of this article is to present baseline data on the prevalences and chronological distributions of enamel hypoplasias, by sex and for all deciduous and permanent anterior teeth, in 300 5 to 15-year-old rural Mexican children. Identification of hypoplasias was aided by comparison to a published standard (Federation Dentaire Internationale: Int. Dent. J. 32(2):159-167, 1982). The location of defects, by transverse sixths of tooth crowns, was used to construct distributions of defects by age at development. One or more hypoplasias were detected in 46.7% (95% CI = 40.9-52.5%) of children. Among the unworn and completely erupted teeth, the highest prevalence of defects was found on the permanent maxillary central incisors (44.4% with one or more hypoplasias), followed by the permanent maxillary canine (28.0%) and the remaining permanent teeth (26.2 to 22.2%) Only 6.1% of the completely erupted and unworn deciduous teeth were hypoplastic. The prevalence of enamel defects on the permanent teeth was up to tenfold greater than that found in studies of less marginal populations that used the FDI method. The prevalence of defects in transverse zones suggests a peak frequency of hypoplasias during the second and third years for the permanent teeth, corresponding to the age at weaning in this group. In the deciduous teeth, a smaller peak occurs between 30 and 40 weeks post gestation. The frequency of defects after three years of age is slightly higher in females than males, suggesting a sex difference in access to critical resources.

Adolescent↗
PubMed1986

CCD line-scan image sensor for the measurement of red cell velocity in microvessels.

A device for measuring red cell velocities in transilluminated microvessels has been developed using a 256 element charge-coupled device (CCD) line scan sensor. An image of the moving red cells is focussed on the device so that it senses optical data along the flow axis. Paired sets of data, separated by a fixed time interval, are sampled by an A/D converter operating at 1 MHz, and transferred to a dedicated microcomputer employing the MC68000 (Motorola Inc.) microprocessor. Velocity is computed from the detected spatial shift occurring in the time between data sets. The computed velocity is converted to an analogue voltage. Calibration is linear, the system is direction-sensitive and it can detect zero motion.

Animals↗
PubMed1986

Comparison of the cardiac effects of beta-adrenoreceptor agonists in anaesthetised and conscious dogs.

The cardiovascular effects of some beta-adrenoreceptor agonists on heart rate, blood pressure and myocardial contractility (maximum rate of change of left ventricular pressure/integrated isometric tension) were measured in pentobarbitone-anaesthetised and conscious, instrumented greyhounds. In anaesthetised dogs isoprenaline increased heart rate and myocardial contractility and reduced blood pressure. Prenalterol and RO 363, in equiactive inotropic doses, induced greater increases in heart rate than isoprenaline if blood pressure fell by less than 25 mmHg. Salbutamol had hypotensive activity at all doses and appeared to be a relatively selective inotrope. None of the agonists caused blood pressure to fall in the conscious dogs. Prenalterol and RO 363 were more effective inotropic stimulants, producing smaller increases in heart rate and more pronounced increases in myocardial contractility. Salbutamol, however, elicited greater increases in heart rate in the conscious animals and the inotropic selectivity demonstrated in the anaesthetised animals was lost. The direct effects of the beta-adrenoreceptor agonists, without modification by reflexes could be observed in the anaesthetised animals. The differences in the actions of the agonists in the conscious animals appear to be attributable to the state of the baroreceptor reflex control system and the relatively enhanced responsiveness of the heart.

Albuterol↗
PubMed1986

An assessment of the effects of minor childhood illness on growth in height and weight.

The effects of common illnesses on the growth of otherwise healthy and well-nourished children living in developed nations have long been assumed to be of negligible consequence. Verifying this assumption is difficult, however, due to the complexity of synergistic relationships between growth variables and the general paucity of appropriate data bases. The present research readdresses this question using a large well-documented longitudinal sample from Colorado. Results of this analysis for associations between illness and growth variables indicate greater stress due to illness during early childhood and greater stress among boys than girls. The results also support the contention, however, that episodes of common childhood illness have neither a major impact on growth nor a lasting effect on long-term growth potential in a well-nourished population living in a developed nation.

Body Height↗
PubMed1985

Inotropic selectivity of salbutamol and terbutaline in anaesthetised, areflexic dogs.

The cardiovascular effects of the selective beta 2-adrenoceptor agonists salbutamol and terbutaline have been evaluated in anaesthetised, areflexic dogs. The preparation was designed to reduce the effects of changes in cardiac function mediated via reflex responses to changes in blood pressure. The effects of the selective beta 2-adrenoceptor agonists on heart rate, hindlimb blood flow, left ventricular pressure, max dP/dt and (dP/dt)/IIT (integrated isometric tension) were compared to those of isoprenaline, while blood pressure was held constant. All three drugs produced dose-dependent increases in heart rate, myocardial contractility and iliac blood flow. When equiactive inotropic doses of isoprenaline and salbutamol were compared, salbutamol produced a significantly lower chronotropic effect. A similar inotropic selectivity was found when terbutaline was compared to isoprenaline. beta 2-Adrenoceptor blockade abolished this selectivity. It is concluded that, in the absence of autonomic reflex activity, the beta 2-selective adrenoceptor agonists are relatively selective inotropic stimulants.

Albuterol↗