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H L Thron

Publications and source records attributed to H L Thron.

At least 19 recordsLinked to original sources
PubMed1985

Comparing the effects of perinatal and later childhood lead exposure on neuropsychological outcome.

Blood lead values (PbB) from cord blood and maternal samples as well as present PbB from venous blood samples were available for 114 six- to seven-year-old children living in or near the city of Nordenham (FRG). These children represented 30% of all children born between July 1975 and August 1976 in the district hospital (N = 383). The range of cord blood PbB was 4-31 micrograms/100 ml (mean = 8.2 micrograms/100 ml) and of maternal PbB was 4-30 micrograms/100 ml (mean = 9.3 micrograms/100 ml), whereas the range for present PbB was 3.9-22.8 micrograms/100 ml (mean = 8.2 micrograms/100 ml). The degree of correlation between maternal and cord blood PbB was 0.79, despite the poor technical quality of many cord blood samples as compared to maternal blood samples (less coagulation). These children were given a battery of neurophysiological and neuropsychological tests. The present report is restricted to psychological performance measures. The test battery covered intelligence (reduced Wechsler Intelligence Scale for Children), visual-motor performance (Bender Test, GFT), serial reaction performance (Wiener Reaction Device), and cued as well as choice reaction times. After correction for confounding by means of stepwise multiple-regression analysis, few significant associations between blood lead levels and performance deficit occurred. In general the degree of association was somewhat stronger for present PbB than for perinatal PbB: With increasing present PbB there was a borderline drop of performance IQ (P less than 0.1), as well as a significant disruption of serial reactions, which was more pronounced for the difficult (P less than 0.01) than for the easier version of the Wiener Device (P less than 0.05). A similar but less pronounced pattern of associations was observed for maternal PbB but not for cord blood PbB. Some influence of perinatal lead exposure on later performance can, thus, still be detected if, in addition to cord blood PbB, maternal PbB is taken into account as well.

Child↗
PubMed1981

Histological examination of the rat after long-term exposure to subtoxic automotive exhaust gas.

Regarding the potential impact of traffic-born air pollutants on public health, in recent years attention has increasingly been focused on the possible effects on the cardiovascular system. In order to investigate this problem further, the influence of long-term exhaust gas exposure on rats has been studied. One hundred Wistar rats of either sex were exposed 5 X 8 h/week up to 28 months to an atmosphere polluted by the emissions of an idling Otto engine, CO concentrations held constant at 90 ppm. A second group (50 rats) was exposed to 250 ppm for 6 months. Blood parameters and body weight were controlled. Specimens of CNS, heart, vessels, kidney etc. were investigated light microscopically. Focal necroses of the myocardium with inflammatory reactions as well as interstitial fibrosis were found in the heart muscle of the 90 ppm group. In the 250 ppm group endothelial proliferations, edema of the intima and deposits of proteoglycanes in the media were observed. We conclude that subtoxic concentrations of CO which only lead to slight morphologic changes may aggravate preexisting lesions caused by high risk conditions, e.g., hypertension or hypercholesteremia.

Animals↗
PubMed1976

[Central venous pressure and blood circulation in orthostatic by changes of the total blood volume in postoperative patients (author's transl)].

In 13 postoperative patients (1st to 9th day) of both sexes, aged 32 to 74, we studied whether an additional volume of 500 ml Haemaccel might demonstrate-as in earlier test series--a correlation between CVP measured in the horizontal position and changes of CVP and Pa measured at atrial level in a partly upright position (tilting angle 45 degrees and 60 degrees of the revolving bed). After volume administration (average: 8.13 ml/kg body weight) and raising of CVP in the horizontal by 3.42 cm H2O corresponding to an E'-value of 0.42 cm H2O/ml/kg body weight, we noticed a significant reduction of the decrease due to orthostasis as well of Pa at heart level as of the "shock index"; at the same time, however, the extent of the CVP decrease registered for all patients increased significantly regardless of tilting angle. Therefore, a correlation between the intravasal filling state and the reaction of orthostatic CVP and Pa may be assumed. In conclusion, the explanation for these results and the relation between the venous filling volume and some pathophysiological functions at the right heart are discussed.

Adult↗
PubMed1975

[Central venous pressure and orthostasis in the postoperative period (author's transl)].

In 18 postoperative patients (1st to 10th day) of both sexes, aged 26 to 74, the relation was studied between the CVP and arterial BP measured in the horizontal and in a partly upright position (45 and 60 degrees respectively). Patients with higher CVPs in the horizontal position generally showed a lesser orthostatic drop of the BP. The fall of CVP which we observed simultaneously in all patients was, however, significantly more marked in the patients with the higher horizontal CVP values, irrespective of the angle of inclination. The cause of these findings appears to be the dependence of the venous hydrostatic indifference point upon the intravascular volume.

Adult↗