[Etiology of stomach carcinoma--opinions and facts--yesterday and today]. / Atiologie des Magenkarzinoms--Meinungen und Fakten--Gestern und Heute.

Recent research demonstrated that views on the etiology of gastric cancer, which had been considered true over decades do not correspond with the real situation. Therefore, efforts for primary prevention of gastric cancer could not be successful. The bacteria Helicobacter pylori is considered today to be an important but not the only etiologic factor of this disease. Eradication of this bacteria decreases the risk of gastric cancer.

Acute inhalation toxicity testing: considerations of technical and regulatory aspects.

The EU regulatory statute for the acute hazard identification of chemicals requires selection of the two most appropriate routes of administration. Testing employing the oral route is mandatory, whereas selection of the dermal or inhalation route requires expert judgement, i.e. considerations of structural alerts with regard to the inherent acute inhalation toxicity as well as the likelihood of dermal and inhalation exposure, respectively. Currently, testing of chemicals requires acute inhalation exposure of 4-h and 1-h durations according the EU classification and labelling and UN Transport Guidelines, respectively. The analysis made revealed that 1-h exposures appear to add little knowledge in addition to existing 4-h LC50 values and a default value of 4 should be used for conversion of 4-h to 1-h LC50 values, independently of the physical state of the chemical. Therefore, also the unit of concentration of exposure atmospheres should be independent of nominal features of the test substance. Hence, the preferred dose metric is mass (mg/liter air) rather than volume (ppm). Taking into account the overall variability of acute toxicity data the recommendations given are classification into the following groups of 4-h LC50 values: < or = 0.05, > 0.05-0.2, > 0.2-1, > 1-5 and > 5.0 mg/l. No distinction should be made concerning vapours and aerosols with regard to units and conversion factors from 4-h to 1-h LC50 values and the default factor of 4 appears to be most suitable. Further differentiation of classification is not indicated due to technical variability of acute inhalation testing and resolution of the acute bioassay.

Endogenous nitrate synthesis in selected infectious diseases and ulcerative colitis.

Investigations into acute and chronic diarrheal patients confirmed the results of animal experiments on the role of cytotoxic activated macrophages in endogenous formation of nitrates. Because a number of inflammatory diseases did not cause a nitrate release in urine, blood, and saliva, the general importance of nitrates to characterize the initiation and course of inflammations must be questioned.

[Nitrate and nitrite concentrations in gastric juice with regard to the physiologic condition of the gastric mucosa]. / Nitrat- und Nitritkonzentrationen im Magensaft unter Berücksichtigung des physiologischen Zustandes der Magenschleimhaut.

In a random sample comprising 101 test persons (35 without and 66 with gastric disorders) nitrate and nitrite concentrations in gastric juice were determined. It was shown that parameters like pH, physiological stage of gastric mucosa, concentrations of bacteria and fungi in gastric juice or nitrate and nitrite concentrations, fungi and bacteria in saliva do not sufficiently characterize the dynamics of nitrate and nitrite in human stomach.

Elevated endogenous nitrate synthesis associated with giardiasis.

Mean nitrate content in the morning urine of 117 patients with giardiasis comprises 155.3 mg/l, which exceeds about 4 fold the normal value. Maximum concentrations of 1000 mg/l were observed. Under treatment with metronidazol (Vagimid) nitrate content at first increased and then restored to normal. Endogenously synthesized nitrate with giardiasis 3-4 fold exceeds the daily nitrate intake by food and, therefore, plays an important role in total nitrate load of the patients.

[Results of clinical and epidemiologic studies of the nitrate problem]. / Ergebnisse klinischer und epidemiologischer Untersuchungen zum Nitratproblem.

Small differences in nitrate intake with the drinking water are not reflected in nitrate contents of saliva and urine of test persons. A correlation of nitrate concentration in body fluids and cancer incidence can be expected hardly. Inflammatory diseases of the gut are frequently accompanied by enhanced endogenous nitrate synthesis and have an essential influence on total nitrate load of the human organism. Nitrate contents in saliva and/or urine are not general indicators of inflammatory processes. As the role of the nitrate ion in humans is not yet understood, the claim remains for a nitrate intake being as low as possible.

[Nitrate and nitrite in the urine, saliva and blood of urologic patients]. / Nitrat und Nitrit in Urin, Speichel und Blut urologischer Patienten.

Nitrate and nitrite contents were determined in urine, saliva, and blood of 298 patients suffering from urological diseases. Crude values of nitrate and nitrite in morning urine without any correction due to density and creatinine are sufficient for epidemiological purposes. Significant correlations exist with vegetables intake and bacteriuria, but not with age, sex, disease, smoking, and medicaments. Neither nitrate nor nitrite may be considered to be general indicators of inflammatory processes in the urogenital tract. According to recent investigations nitrite formation during bacterial infections must be seen in connection with simultaneously occurring macrophage activation, as the latter one is catalyzing the formation of carcinogenic N-nitroso compounds from nitrite and secondary amines.

[Nitrate and nitrite content of the saliva, urine, blood and cerebrospinal fluid in patients at an infection clinic]. / Nitrat- und Nitritgehalt in Speichel, Urin, Blut und Liquor von Patienten einer Infektionsklinik.

In 254 patients of a ward for infectious diseases the authors demonstrated that inflammatory diseases are frequently accompanied by an increase in nitrate content of the blood, urine and saliva. This effect is especially evident in gastrointestinal disorders. Correlations of nitrate with indicators of the inflammatory process are, if at all, very weak. The endogenous synthesis of nitrate may be of importance for the total nitrate load to the organism especially in children or patients with long-lasting inflammatory disease.

[Current aspects of giardiasis]. / Aktuelle Aspekte der Giardiose.

Modern epidemiological, clinical, diagnostic and therapeutic aspects of giardiasis are described.

[Pilot study of the nitrate, nitrite and bacterial content of human saliva as a function of environmental factors]. / Pilotstudie über den Nitrat-, Nitrit- und Bakteriengehalt des menschlichen Speichels in Abhängigkeit von Umweltfaktoren.

In a random sample comprising 160 test persons nitrate (12.4 +/- 7.6 mg/l) and nitrite (5.7 +/- 4.0 mg/l) concentrations as well as bacteria counts in saliva were determined. No dependence of the values from age and sex could be detected, whereas smokers have lower concentrations of both nitrate and nitrite. Persons suffering from inflammatory diseases did not have enhanced nitrate concentrations. Role of bacteria for nitrite production is confirmed. Patients, regularly taking nitro-remedies, showed enhanced NO3--(25.8 mg/l) and NO2--(8.4 mg/l)-values.

The utilization of nitrate and nitrite by Streptococcus salivarius in the saliva.

Streptococcus salivarius BU 104 utilizes nitrate and nitrite only under anaerobic conditions and thus adds to the nitrite exposure of the human organism.

Statistical investigations into the measured DALA--discharge in the urine of infants.

Using a sample of the size 353 on day-nursery children, the authors show that the DALA-U increase, which is due to the absorption of lead and other substances, does not display any age or sex dependence. A dependence upon the day nursery's location is assumed. The authors elaborate on the statistical problems (normal distribution) and the boundary value problems associated with the various DALA-U values measured. Large sample sizes are required to find a final clarification of the relationships.

[Profile of polycyclic aromatic hydrocarbons in the waters of the Estonian SSR]. / Profile polyzyklischer aromatischer Kohlenwasserstoffe in Gewässern der Estnischen SSR.

The profiles of various polynuclear aromatic hydrocarbons (PAH) in water and bottom sediments of some rivers of the Estonian SSR and bays of the Baltic Sea, as well as algae gathered from the latter waterbody, have been studied. These data were compared with profiles in oil-shale emissions, sewage and automobile exhaust gases. No distinct differences of the emission profiles could be detected and therefore it seems to be impossible to fix the main source of the PAH pollution of the waterbodies.

[Determination of 3,4-benzopyrene-content in seeds before and after germination (author's transl)]. / Bestimmung des 3,4-Benzpyrengehaltes in Pflanzensamen vor und nach der Keimung

The content of 3,4-benzopyrene in various seeds before and after germination in different nutritive solutions is determined. The hygienic meaning of the results is discussed.