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H Habs

Publications and source records attributed to H Habs.

At least 19 recordsLinked to original sources
PubMed1985

[The future of hygiene in a world of technology--hygiene and historicism].

Stimulated by "historicism", a term coined by Karl Popper, statements uttered by the philosophers Heidegger, Jaspers and Guardini are analysed to see whether historical forecasts are possible which justify a gloomy outlook of the world's future, such as is presently spreading as a result of the concern about an excessive invasion of our life by technology. Man has liberated himself from his original dependence on the natural forces of his environment thanks to the technology he has developed. He has severed his ties with this environment, but must not be overwhelmed by technocracy. Also, we hygienists, should allow for the historical development of our natural and social environment, in addition to the results of laboratory analyses and field studies.

Forecasting↗
PubMed1984

Negative dose-response study for carcinogenicity of orally administered rutin sulfate in Sprague-Dawley rats.

Rutin is a ubiquitous naturally occurring flavonoid, which is used in a number of drugs. It was tested for carcinogenicity in Sprague--Dawley rats as a water-soluble mixture of sodium salts of sulfuric acid esters. Over 2 years, doses ranging from 10 to 500 mg/kg body wt of rutin sulfate (expanding factor 2.66) were administered by gavage 3 times a week to 4 groups of rats comprising 12 males and 12 females each. A control group was treated with tap water. Age-adjusted analysis of tumor rates did not provide any evidence for rutin sulfate to be carcinogenic under the conditions of this bioassay.

Administration, Oral↗
PubMed1983

Combined effects of fast-neutron irradiation and subcutaneously applied carbon tetrachloride or chloroform in C57Bl6 mice.

Male and female C57Bl6 mice received a single whole-body dose of irradiation with 170 rad or 330 rad of fast neutrons. Nine weeks later they were given a single subcutaneous injection of carbon tetrachloride or chloroform. Chloroform did not influence the occurrence of tumours, but carbon tetrachloride markedly increased the incidence of radiation-induced liver carcinomas.

Animals↗
PubMed1983

Fluoro-substituted N-nitrosamines. 6. carcinogenicity of N-nitroso-(2,2,2-trifluoroethyl)-ethylamine in rats.

N-Nitroso-(2,2,2-trifluoroethyl)ethylamine (F-3-NDEA) was tested for carcinogenic activity in male Sprague-Dawley rats at 4 dose levels. The compound was given by gavage twice weekly. Treatment related tumors were observed in all experimental groups and appropriate dose-response relations were seen. The main tumor localisations were the esophagus and the nasal cavity. F-3-NDEA therefore is carcinogenic in rats after oral administration, a biological effect to be expected since it had been shown earlier that this compound is enzymatically activated by dealkylation and is weakly mutagenic in bacterial assay systems. A change in organotropism is observed when comparing carcinogenicity of F-3-NDEA with the predominantly hepatocarcinogenic activity of parent N-nitrosodiethylamine.

Animals↗
PubMed1983

Influence of a non-synthetic diet with a high fat content on the local occurrence of colonic carcinomas induced by N-nitroso-acetoxymethylmethylamine (AMMN) in Sprague-Dawley Rats.

Low doses (0.1 mg/animal administered fortnightly for 48 weeks) of the local carcinogen N-nitrosoacetoxymethylmethylamine (acetoxymethylmethylnitrosamine, AMMN) were administered intrarectally to Sprague-Dawley rats fed a standard diet (Altromin pellets) and resulted in a 22% incidence of colonic cancer. When the carcinogen was administered to rats kept on a nonsynthetic diet with a high fat content for their entire life-time, the colonic cancer risk was identical. The results demonstrate that an unbalanced high-fat diet need not necessarily increase the colonic cancer risk caused by a chemical carcinogen.

Animals↗
PubMed1982

Fluoro-substituted N-nitrosamines. 5. Carcinogenicity of n-nitroso-bis-(4,4,4-trifluoro-n-butyl)amine in rats.

N-Nitroso-bis-(4,4,4-trifluoro-n-butyl)amine (F-6-NDBA) has been synthesized as a derivative of the rat urinary bladder carcinogen N-nitrosodibutylamine (NDBA). Its chronic administration by gavage to Sprague-Dawley rats induced a significant incidence of malignant tumors of the liver and the lungs. Tumors in the liver were diagnosed as multifocal hepatocellular carcinomas and those of the lungs were mainly squamous cell carcinomas. No tumors were observed in the urinary bladder. This confirms earlier results from metabolism and animal carcinogenicity experiments indicating the importance of metabolic oxidation at the terminal carbon atom of NDBA for its organ-specific effects. This metabolic omega-oxidation is blocked in F-6-NDBA.

Animals↗
PubMed1982

[Not Available].

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Greece, Ancient↗
PubMed1982

[Immunological concepts in Thucydides' works].

In the second volume of his History of the Peloponnese War, Thukydides described the course and the clinical picture of the so-called Attican Pest. It is demonstrated, by an analysis of the text of chapter 51, that Thukydides had recognized the difference between resistance and acquired specific immunity.

Allergy and Immunology↗
PubMed1982

Carcinogenicity of N-nitrosodiethanolamine in rats at five different dose levels.

N-nitrosodiethanolamine, an N-nitroso compound of environmental significance, has been tested for carcinogenicity in male Sprague-Dawley rats at five different dose levels. Administration p.o. in the drinking water of 1.5, 6, 25, 100, or 400 mg N-nitrosodiethanolamine per kg per day was tolerated well. Median total doses administered were between 0.86 g/kg body weight at the highest and 100.3 g/kg body weight at the lowest dose level. Treatment-related tumors were observed in the liver and the nasal cavity. The induction of hepatocellular carcinomas was clearly dose related, low doses also inducing benign lesions. Other liver tumors were of mesenchymal and ductal origin and nasal cavity neoplasms were diagnosed as squamous-cell carcinomas and neuroepitheliomas of the olfactory epithelium. Statistical evaluation of the 1.5-mg/kg dose regimen clearly indicates that even such low doses are carcinogenic. This potent carcinogenic activity is surprising since a high percentage (60 to 90%) of an administered dose of N-nitrosodiethanolamine is excreted unchanged in the urine. Thus, we propose that an as yet unidentified metabolite may possess high carcinogenic potential.

Adenocarcinoma↗
PubMed1982

No evidence of carcinogenicity of N-nitrosocimetidine in rats.

Cimetidine is a histamine H2-antagonist. Since in vitro formed N-nitrosocimetidine (NC) has been shown to be genotoxic, we investigated it for carcinogenicity. Two groups of 40 Sprague-Dawley rats each received 500 and 50 mg/kg NC, respectively, by gavage twice weekly for one year with subsequent lifetime follow-up. An additional 40 rats were given the structurally related carcinogen methylnitro-nitrosoguanidine (MNNG) orally at weekly doses of 80 mg/kg for 3 months. 100 animals served as untreated controls. MNNG-treated rats died with carcinomas of the forestomach (median induction time: 226 days). No evidently treatment-related tumors were seen in animals receiving NC. The median survival time in both NC-treated groups was reduced (400 and 393 vs. 630 days in the control). No evidence of carcinogenicity of NC was seen in this bioassay. It is concluded that NC is not carcinogenic, or at least significantly less so than MNNG.

Animals↗
PubMed1982

Carcinogenic and mutagenic activity of an alkaloidal extract of Senecio nemorensis ssp. fuchsii.

The alkaloidal residue obtained after extraction of dried and pulverized Senecio nemorensis ssp. fuchsii contains two pyrrolizidine alkaloids, i.e. fuchsisenecionine and senecionine. In a chronic experiment doses of 8 mg/kg and 40 mg/kg b.w. of the alkaloidal extract were given five times a week by gavage to male and female Sprague-Dawley rats. The study was terminated after 114 weeks. Repeated serum analysis demonstrated a dose-related elevation of serum glutamic oxalacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT) and alkaline phosphatase (AP). Beside its hepatotoxic effect, the treatment proved to be hepatocarcinogenic, showing female rats to be more sensitive than males. Tumors diagnosed were of hepatocellular and angiogenic origin. In age-adjusted analysis the occurrence of these neoplasms revealed a clear dose-related trend (p less than 0.00005). In the in-vitro mutagenicity test system with V 79 Chinese hamster cells, the alkaloidal extract exerted a weak but dose-related mutagenic activity. Under the conditions used the alkaloidal extract of Senecio nemorensis ssp. fuchsii is a genotoxic carcinogen.

Alkaline Phosphatase↗
PubMed1981

Effect of the pretreatment with disulfiram on the toxicity and antitumor activity of 1-(2-hydroxyethyl)-3-(2-chloroethyl)-3-nitrosourea in Sprague--Dawley rats.

Pretreatment with disulfiram (DSF, 1000 mg/kg p.o.) 2 h prior to intraperitoneal injection of 1-(2-hydroxyethyl)3-(2-chloroethyl)-3-nitrosourea (HECNU, NSC 29485) reduced the acute toxicity of HECNU by 50% in Sprague--Dawley rats. Thereafter the effect of this additional treatment on the chemotherapeutic activity of HECNU was investigated. After intraperitoneal transplantation of Yoshida sarcoma ascites cells untreated rats had a median survival time of 8 days. The therapeutic response to a single application of HECNU alone or of DSF followed by HECNU was compared. HECNU was injected intravenously at logarithmically increasing doses from 15 to 61.8 mg/kg. The maximum survival time was increased to about 14 days in rats treated with HECNU. Pretreatment with DSF (1000 mg/kg) resulted in identical or slightly higher life expectancies; it thus reduced the toxic side effects of HECNU without inhibiting its antitumor potency.

Animals↗
PubMed1981

[An approach to bacteriological taxonomy by application of Immanuel Kant's transcendental dialectics (author's transl)].

After having altered the name of International Committee for Bacteriological Nomenclature in International Committee on Systematic Bacteriology in 1970, the latter will also have to reflect upon the objects of taxonomy. An approach thereto is recognizable in the revision of the International Code of Nomenclature of Bacteria in 1975. Considerations are being made whether a classification of bacteria does justice to the laws of homogenicity, specification and continuity as laid down by Kant in his transcendental dialectic. Most important of all are definition and determination of the taxon species. As far as contents go the latter is not possible from the biological point of view but applicable to its range in application of the regulations of the code. Within the priorities of taxa the species adopts a preferential position because conceptions of applied bacteriology are contained therein. The variety of infra-subspecific subdivisions is taken into consideration; as far as the formae speciales are concerned considerations as made with regard to species apply.

Bacteria↗
PubMed1980

Effect of the intermittent administration of N-nitrosopyrrolidine (NPYR) on the tumor incidence in Sprague-Dawley rats.

N-Nitrosopyrrolidine (NPYR) was administered orally to 320 Sprague-Dawley rats. An additional group of 80 rats served as an untreated control. There were four experimental groups in which the effects of different periods of dosing and varied intervals without treatment were compared. The total dose for all the groups was constant and was 792 mg/kg body weight. The schedules of carcinogen application had a significant effect on the observed cancer risk. The different tumor indicences in the individual groups could not be attributed to differences in the survival pattern, but were related to the changes in the different treatment schedules.

Animals↗
PubMed1980

Influence of thioctic acid (alpha-lipoic acid) on N-nitroso-diethylamine-induced carcinogenesis in male sprague-dawley rats.

Male Sprague-Dawley rats received 10 mg/kg body weight of N-nitroso-diethylamine by gavage twice weekly for life (group 1). An additional daily application of thioctic acid (alpha-lipoic acid) in drinking water (45 mg/kg body weight/day) (group 2) and 180 mg/kg body weight/day (group 3) did not significantly influence tumor frequencies, induction times and histology of the induced liver and esophageal tumors. A postulated enhancing mechanism on tumor development due to thioctic acid treatment could not be demonstrated.

Animals↗
PubMed1979

[Nosology, epidemiology and bacteriological taxonomy: salmonella infections as an example (author's transl)].

Salmonella infections are discussed as an example of the interdependence of the classification of infectious diseases on the one hand and the taxonomy of bacteria on the other. The term paratyphoid was first created as a name for a disease but was later turned into a common name for the cause and then refined into a specific epitheton of a species of bacteria. It was difficult to create terms for pathology as long as a reliable differentiation of related species of bacteria was not possible, so both a typhoid and an enteric form of paratyphoid fever were referred to, superimposing the clinical differentiation of typhoid fevers and food poisoning (enteritis infectiosa). Epidemiology and bacteriology cannot expect their classifications to determine the classification of bacteria on the level of genus and subgenus, but systematic bacteriology should not conserve or create species and subspecies that are unnecessary for applied medical bacteriology. The needs of epidemiology usually require identification and determination of serovar, biovar and phagovar of the individual strain, but for pathology it is important to classify series of strains on the basis of certain combinations of serovars, biovars, and phagovars as special forms.

Humans↗