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Biomedical subjects

H Falk

Publications and source records attributed to H Falk.

At least 127 records · Page 7Linked to original sources
PubMed1978

Development of hepatic angiosarcoma in man induced by vinyl chloride, thorotrast, and arsenic. Comparison with cases of unknown etiology.

Examples of human angiosarcoma following exposure to vinyl chloride, Thorotrast, or arsenic (medicinal and industrial) and cases, including children, of unknown etiology were studied to establish diagnostic criteria and to study their evolution. The uniform evolution suggests an environmental factor also in the cases of unknown etiology, which may be established by epidemiologic studies. A precursor stage is charaterized by areas of combined hyperlasia of hepatocytes and a variety of sinusoidal and perisinusoidal cells associated with excess of reticulin and with sinusoidal dialation. The diagnostically useful picture in silver impregnations indicated reticulum formation by the perisinusoidal cells, presumably the libocytes. The hepatocytic proliferation suggests a hepatocarcinogenic but usually not fully expressed potential. The mixed hyperplasia of the various sinusoidal cells proceeds to an overgrowth of angiosarcoma cells, presumably derived from endothelial cells. In early stages they are usually in contact with hepatocytes (intralobular growth). A trabecular arrangement results from loosening of the lobular plate arrangement by dilatation of sinusoids, leading to primary peliosis. With disappearance of the hepatocytes, various growth patterns develop, terminating in nodular, solid angiosarcoma composed of either spindle-shaped or polyhedral cells which undergo necrosis or hemorrhage (secondary peliosis). The interaction between hepatocytes and sinusoidal cells requires elucidation.

Adolescent↗
PubMed1977

Performance characteristics of rules for internal quality control: probabilities for false rejection and error detection.

When assessing the performance of an internal quality control system, it is useful to determine the probability for false rejections (pfr) and the probability for error detection (ped). These performance characteristics are estimated here by use of a computer stimulation procedure. The control rules studied include those commonly employed with Shewhart-type control charts, a cumulative sum rule, and rules applicable when a series of control measurements are treated as a single control observation. The error situations studied include an increase in random error, a systematic shift, a systematic drift, and mixtures of these. The probability for error detection is very dependent on the number of control observations and the choice of control rules. No one rule is best for detecting all errors, thus combinations of rules are desirable. Some appropriate combinations are suggested and their performance characteristics are presented.

Chemistry, Clinical↗
PubMed1977

[Clinical studies on analgesia in obstetrics using intravenous administration of droperidol and pethidin (author's transl)].

In 70 healthy women under labor, the clinical properties of the combination DHB (0,1 mg/kg) and Pethidin (0.4 mg/kg) was studied for analgesia purposes in obstetrics; on request, Pethidin was given repeatedly. The fallowing conclusions can be drawn from this study: 1. The recommended "analgesic mixture" of DHB and Pethidin i.v. in the above mentioned doses is usually without harm to mothers and fetuses or new born respectively. 2. The Pethidin dosage, used in this study, agrees with the doses, recommended in the literature (0,4 mg/kg/h). 3. There was no difference between I-para, II, III-para etc., as far as the Pethidin requirement are concerned. 4. The analgesic properties of the mixture, judged by using clinical criteria only, were not quite convincing. This may be due to an increase of the intensity of uterine contractions by the mixture itself.

Adult↗
PubMed1976

Genetic risks of vinyl chloride.

A study of pregnancy outcome among wives of workers exposed to vinyl-chloride monomer (V.C.M.) indicated that, in comparison with controls, there was a significant excess fetal loss in the group whose husbands had a primary exposure to V.C.M., whereas no differences between the groups were observed before the husband's exposures. The difference in fetal death-rates for the post-exposure comparisons was a reflection of a greater fetal loss associated with the wives younger-aged husbands. The significant excess did not seem to be the result of bias from interviewers, respondents, nor from women who had experienced chronic abortions weighting the results. These findings, in conjunction with the demonstration of a mutagenic response via microbial test systems and with observations of significant excesses of chromosomal aberrations among workers exposed to V.C.M., raise scientific and public-health concern for the possible genetic risks of V.C.M. to man.

Age Factors↗
PubMed1976

Respiratory tract illness in meat wrappers.

A questionnaire survey was done in 152 Houston supermarkets to assess the prevalence of respiratory tract symptoms in meat wrappers exposed to the thermal decomposition fumes of polyvinyl chloride (PVC) film wrap and in two supermarket control groups (checkers and meat cutters). Meat wrappers had increased respiratory tract symptoms; 12% of meat wrappers who smoked (vs 6% and 2% of controls) and 5% of meat wrappers who did not smoke (vs 0% and 0% of controls) had multiple respiratory tract symptoms. It is probable that a large number of meat wrappers have mild symptoms with some progressing to more severe respiratory impairment or clinical asthma.

Adult↗
PubMed1976

Comparative studies on the structural proteins of T3 and T7 phages.

A comparison of the coat protein patterns of the wild types of the related phages T3 and T7 on SDS polyacrylamide gel electrophoresis was carried out. After infection of the nonpermissive host with T7 amber mutants in genes 7, 11, 12, 13 or 17 and T3 amber mutants in genes 11, 12, 13 and 17 respectively, noninfectious, DNA containing particles were produced. The protein pattern, as well as electron microscopy of defective particles of T3 and T7 led to the conclusion that the proteins specified by genes 11, 12, 13 and 17 are tail proteins whereas the proteins coded by genes 7, 8, 10, 14, 15 and 16 enter the head structure. The "serum blocking protein" (gene 17 product) seems to play a different role in the assembly of T3 and T7 tails, since T3 particles defective in gene 17 did not show any tail structure connected with the head whereas T7 particles defective in gene 17 had a tail which looked different from that of the wildtype. Treatment of wildtype particles with ammonium nitrate or sodium pyrophosphate led to morphologically abberrant forms which had partially or completely lost the hexagonal head structure. After treatment with ammonium nitrate ball-like structures were obtained, both for T3 and T7. However, in the case of T3 these abberrant forms contained the proteins specified by genes 7, 8 and 10 whereas those derived from T7 contained only the proteins specified by genes 8 and 10. Sodium pyrophosphate treatment of T3 and T7 wildtype particles led to a release of the phage tails. The isolated tails were examined by electron microscopy thus revealing for the first time a detailed substructure of the T3 and T7 phage tails. In order to find out more about the tail proteins, absorption experiments with isolated bacterial cell walls were carried out.

Adsorption↗
PubMed1976

Vinyl chloride-associated liver disease.

Although polyvinyl chloride has been produced from vinyl chlride monomer for more than 40 years, recognition of toxicity among vinyl chloride polymerization workers is more recent. In the mid 1960s, workers involved in cleaning polymerization tanks were found to have acro-osteolysis. In 1974, the same population of workers was found to be at risk for an unusual type of hepatic fibrosis and angiosarcoma of the liver. We describe two cases of vinyl chloride-associated liver injury, one of hepatic fibrosis and one of angiosarcoma. Histologic features of these lesions are similar to the hepatic fibrosis and angiosarcomas resulting from chronic exposure to inorganic arsenicals. Preliminary studies suggest that the toxicity of vinyl chloride may result from formation, during high-dose exposure, of active metabolites by mixed function oxidases of the liver. Epidemiologic studies indicate an increased incidence not only of liver disease, but also of cancers of the brain, lung, and possibly other organs.

Adult↗
PubMed1975

Acute nonlymphocytic leukemia. An adult cluster.

Between 1970 and 1973, seven cases of acute nonlymphocytic leukemia were diagnosed in the village of Elmwood, Wis, and the surrounding area. The patients ranged in age from 14 to 97 years. Interpersonal relationships were noted among all patients in the group. This cluster of cases represents a greater than 20-fold increase in the expected incidence of this disease for this population. Morphologic similarities in the blast cells were seen in all cases. This cluster of cases may bear a relationship to bovine leukemia since the town was located in dairy farming country and because a number of the patients had either worked at or lived near the town creamery.

Acute Disease↗
PubMed1975

Characteristics of cases of angiosarcoma of the liver among vinyl chloride workers in the United States.

A total of 13 cases of ASL have been documented to date among VC workers in four different plants in the United States. In this particular industrial population, this number of cases represents at least a 400-fold increase over expected incidence for this extremely rare tumor. The first case occurred in 1961. Average age at diagnosis is 48.2 years. Average length of time between initial VC work and diagnosis has been 20.3 years. A detailed review of 7 cases associated with one plant revealed that clinical features varied from little or no overt illness prior to diagnosis to advanced liver disease with portal hypertension and marked splenomegaly. Portal fibrosis was present in all 7 of these ASL cases as well as in 4 additional cases with non-malignant liver disease among VC workers at the same plant. These findings suggest that exposure to VCM in industrial settings can produce hepatic fibrosis with angiosarcoma as a late manifestation. Conventional liver function tests may not be sensitive indicators of such liver impairment, at least in its early stages.

Adult↗
PubMed1975

Vinyl-chloride-induced liver disease. From idiopathic portal hypertension (Banti's syndrome) to Angiosarcomas.

Histologic examination of liver tissue (eight autopsy and 18 biopsy specimens) and five spleens from 20 workers with vinyl chloride polymerization showed hepatic angiosarcomas in 15. In addition, a peculiar pattern of progressive portal-tract, inconspicuous intralobular and conspicuous capsular fibrosis was observed in the five workers without angiosarconma, in all the seven patients with angiosarcoma from whom tumor-free portions of the liver were available, and in two tumor-free biopsies from patients subsequently found to have angiosarcoma. The fibrosis was accompanied by splenomegaly. Hypertrophy and hyperplasia of both hepatocytes and hepatic and splenic mesenchymal cells were also seen. The histologic similarity to chronic inorganic arsenical poisoning, in which angiosarcomas also occur, and to idiopathic portal hypertension (Banti's syndrome) suggests that the latter syndrome at times results from unknown toxic, possible environmental, chemicals.

Autopsy↗