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Biomedical subjects

K Witt

Publications and source records attributed to K Witt.

At least 55 records · Page 3Linked to original sources
PubMed1989

Chromosome aberration and sister chromatid exchange tests in Chinese hamster ovary cells in vitro. III. Results with 27 chemicals.

Twenty-seven chemicals previously tested in rodent carcinogenicity assays were tested for induction of chromosomal aberrations (ABS) and sister chromatid exchanges (SCE) in Chinese hamster ovary (CHO) cells as part of a larger analysis of the correlation between results of in vitro genetic toxicity assays and carcinogenicity bioassays. Chemicals were tested up to toxic doses with and without exogenous metabolic activation. Seventeen of the chemicals tested were carcinogens; only two of these were negative for both ABS and SCE. Of the eight noncarcinogens tested, four were negative for both endpoints (ABS and SCE) and four gave a positive response for at least one endpoint. Of the remaining two chemicals, one, diallyl phthalate, gave an equivocal response in the bioassay and a positive response in these CHO cell cytogenetics tests. The other chemical, 2,4-toluene diisocyanate, was tested for carcinogenicity as a mixture with the 2,6-isomer; the mixture was carcinogenic, but the cytogenetic test results for the 2,4-isomer were negative. Only six of the 27 chemicals tested produced an effect in one endpoint alone; the other 21 were either positive or negative for both ABS and SCE. Only one of the 27 chemicals tested required S9 for a positive response in the SCE test; two chemicals required S9 for a positive result in the ABS test. Experiments with unsynchronized CHO cells demonstrated that mean SCE frequency increased with increasing culture time, and this may have been a factor in the positive results obtained for five chemicals in the SCE test under conditions of delayed harvest.

Animals↗
PubMed1989

[Incidence of appendectomy and length of hospital stay in a region of West Germany].

Based on public health routine data, a study on the incidence of appendectomies was carried out in the Federal Republic of Germany. The result of 130 appendectomies per 100,000 inhabitants per annum comes very close to the findings made in England and Wales though it only represents one fifth of the figure, Lichtner and Pflanz had established for some other region about 20 years ago. Duration of hospitalization averaged 10.6 days, thus showing a reduction of 2 days compared to the earlier study. In England and Wales however, the average length of stay in hospital came up to only 5.6 days. The length of stay, standardized by age and sex, showed differences of more than 4 days on the various wards. The possible influences of institution inherent factors on the frequency of operations and on the duration of hospitalization are discussed.

Adolescent↗
PubMed1989

The long-acting somatostatin analogue SMS 201-995 causes malabsorption.

Somatostatin and its long-acting analogue SMS 201-995 (Sandostatin) have been suspected of causing steatorrhoea. The aim of this study was to examine the effect of SMS 201-995 on fat assimilation in healthy subjects, using 14C-triolein and 3H-oleic acid as tracers of dietary triglycerides and free fatty acids, respectively, and 51CrCl3 as non-absorbable marker. Six healthy male volunteers participated in the double-blinded, randomized, crossover study. In each test period either 1 ml of SMS 201-995, containing 200 micrograms, or 1 ml of isotone saline was given subcutaneously three times within 16 h. Faeces were collected for 3 days, every stool separately. The faecal 14C-triolein and 3H-oleic acid excretion was calculated from two aliquots of faeces. In addition, the mean daily faecal fat excretion was estimated. When placebo was given, the median 14C-triolein excretion was 1% (range, 0.9-1.6%), the median 3H-oleic acid excretion was 5% (range, 3-10%), and the daily faecal fat excretion was 4 g/day (range, 1-6 g/day), all within normal limits. When SMS 201-995 was given, the faecal 14C-triolein excretion increased to a median of 75% (range, 43-119%), the 3H-oleic acid excretion increased to a median of 82% (range, 46-126%), and the faecal fat excretion increased to a median of 22 g/day (range, 4-34 g/day), all clearly above normal. The faecal 14C-triolein/3H-oleic acid test showed triglycerides and free fatty acids to be equally malassimilated, which indicates malabsorption.

Adult↗
PubMed1989

Ranitidine for improvement of delayed hypersensitivity response in patients with sepsis.

Twenty-five patients admitted to intensive or high-dependency surgical care units were randomized to receive ranitidine intravenously 50 mg every 6 hours for 8 days or no ranitidine. All had septicemia or intra-abdominal sepsis, with body temperature greater than or equal to 38.5 degrees C for more than 48 hours despite comprehensive medical and/or surgical treatment. Cell-mediated immunity was assessed by skin testing with seven common delayed type hypersensitivity antigens applied on days 1, 4 and 7 and all tests were read at 48 hours, i.e. on days 3, 6 and 9. The ranitidine/non-ranitidine regimen was initiated on day 1 and continued until day 9. Severity of illness was evaluated before and 3, 6 and 8 days after initiating the study, using the APACHE II scoring system. The scores before and during the study were similar in the ranitidine and non-ranitidine groups. Delayed type hypersensitivity improved in patients treated with ranitidine (p less than 0.001), but was unchanged in the untreated group (p greater than 0.7). These observations may suggest potential beneficial effects of ranitidine therapy in patients with trauma-induced immunosuppression.

Adult↗
PubMed1987

Screening for glaucomatous visual field loss with automated threshold perimetry.

We examined 27 glaucomatous eyes and 154 normal eyes with automated threshold perimetry. Previously suggested algorithms for detecting mild to moderate glaucomatous visual field loss, primarily by comparing the sensitivity of corresponding clusters of points above and below the horizontal meridian, yielded results remarkably consistent with those of our earlier series: 93% (25 of 27) of abnormal and 88% (135 of 154) of normal eyes were correctly identified. Excluding unreliable examinations increased specificity from 88% to 93%. Test duration was similar to results with the Field Analyzer's older, purportedly slower operating system.

Aged↗
PubMed1984

Transfer of matching-to-figure samples in the pigeon.

Three pigeons were trained on a modified six-key matching-to-sample procedure. The third peck on the figure-sample key (which presented a bird, hand, face, beetle, rabbit, fish, flower, or red hue, as the sample) lighted only one comparison key. Every three additional pecks on the sample lighted another comparison key, up to a maximum of five keys. Pecks on keys of matching figures produced grain. Pecks on nonmatching keys (mismatches) turned off all lights on the comparison keys and repeated the trial. Three figures were used during acquisition. The birds learned to peck each sample until the matching comparison stimulus appeared on one of three comparison stimulus keys, and then to peck that key. Later, five novel stimuli, employed as both sample and comparison stimuli, and two additional matching keys were added. Each bird showed matching transfer to the novel samples. The data suggest that the birds may have learned the concept of figure matching rather than a series of two-component chains or discrete five-key discriminations.

Journal Article↗
PubMed1980

[Bladder cancer and old age. Study of the occurrence and status of diagnosis in the GDR with respect to old age].

Bladder cancer and age. A study on the morbidity and on the state of detection and treatment with respect to age in the G.D.R. Malignant neoplasms of the urinary bladder account for about 1,400 registered new cancer cases and 1,100 deaths annually in the G.D.R. As compared with other developed industrialized countries, incidence and mortality from bladder cancer is relatively low in the G.D.R. Analysis of age-standardized incidence and mortality from 1956 to 1974 gives no clearcut evidence of an increase of bladder cancer morbidity. A regional analysis of the state of detection and treatment of bladder cancer was performed in the capital Berlin (1955-1974) and the city of Dresden (1969/70). It can be shown that there is a decrease of localized stages, of radically operated tumours and of survival rates with increasing age at time of diagnosis. In Berlin more than 30 per cent of new cases are 75 years and older. Localized stages I and II amount to nearly 50 per cent of newly registered bladder cancer cases. While mean age of patients increased in the observation period and stage distribution remained about equal, rate of radical interventions showed a slight increase reflecting a more aggressive approach to treatment. Higher survival rates can be expected in the future.

Age Factors↗
PubMed1979

[An attempt to analyze the state of gastric cancer control in the German Democratic Republic (author's transl)].

Starting from the records of the county cancer control offices, an attempt is made to analyze the quality of detection and treatment of gastric cancer in the G.D.R. Possibilities and results of curative treatment strongly depend upon the extent of the disease and the age of the patient at the time of diagnosis. During the period of observation (Berlin 1955--1974, county Königs Wusterhausen 1960--1974), the proportion of elderly patients (65-yrs.) increased, stage distribution remained about the same, the rate of curative operations increased a little. When comparing the situation in the capital Berlin with the district Erfurt, the city of Dresden and the rural county Königs Wusterhausen, it can be demonstrated that the quality of diagnosis and treatment in Berlin is somewhat better then in the other teritories.

Adult↗
PubMed1979

[Breast cancer detection and treatment (author's transl)].

The records of the district offices for cancer control in Berlin and Königs Wusterhausen were used in order to analyse changes in the detection and management of female breast cancer between 1955 and 1974. The proportion of new cases younger than 45 years has increased from 8 percent to about 13 percent. Since 1970 there has been an increase in stage I and a decrease of stage IV. From 1960 to 1969 only 71 percent of all patients were radically operated upon, but in 1973/74 the proportion rose to nearly 75 percent. The tendency to extend the indication for radical surgery affects elderly women (65 to 74 years) more than younger patients. Survival rate depends on clinical stage, age and mode of treatment. It can be expected that the survival rate will increase with more radical surgery.

Adult↗
PubMed1976

Resistance of Neisseria gonorrhoeae grown in vivo to ingestion and digestion by phagocytes of human blood.

Attempts to study quantitatively the phagocytosis of gonococci from urethral pus failed because of the small numbers of organisms and technical difficulties. However, gonococci from chambers implanted subcutaneously in guinea pigs, which were similar to gonococci from urethral pus in their resistance to killing by human serum, were obtained in sufficient quantities for comparison in phagocytosis tests with the in vitro grown strains from which they were derived. Microscopic and viable counts of gonococci in phagocytes showed that in vivo grown organisms (strain BSV) were readily phagocytosed by human polymorphonuclear phagocytes. There was little difference betweee to ingestion. There was, however, a marked difference in the intracellular survival of strains BSV and BS during the first hour of phagocytosis. Whereas BSV organisms survived well, many BS organisms were killed. Subsequently, strain BSV and the survivors of the strain BS inoculum responded similarly to the intracellular bactericidins. These results were supported by electron microscopy of infected phagocytes. Resistance of gonococci in vivo to ingestion and digestion by human phagocytes seem to be important facets of the pathogenesis of gonorrhoea.

Humans↗
PubMed1976

Resistance of Neisseria gonorrhoeae to ingestion and digestion by phagocytes of human buffy coat.

In tests in vitro with the phagocytes of human buffy coat, a recent isolate of Neisseria gonorrhoeae, which was pilated, formed small colonies and resembled the virulent Kellogg type 2 (strain BS), resisted ingestion more than did another isolate (strain AL), which was non-pilated, formed large colonies and resembled the avirulent Kellogg type 4. Some members of both strains survived for significant periods within the phagocytes in test conditions that tended to minimise rather than maximise such survival; and strain BS had a greater capacity for intracellular survival than strain AL, with some of its members surviving for at least 8 h. Resistance to phagocytic ingestion is one important invasive mechanism of gonococci, and resistance to phagocytic digestion may also play a role in pathogenicity.

Cell Count↗
PubMed1976

[Malignant neoplasms of the stomach in Berlin, capital of the G.D.R. - An analysis of the state of diagnosis and treatment].

In Berlin, capital of the German Democratic Republic, 7,386 new cases of gastric cancer (ICD 151) were registered in the period from 1955 to 1969 and in year 1973. 52 percent of patients were male. Percentage of cases 75 years old and more, increased from 21% (1955-1959) to 36% (1965-1969). There were only slight changes in incidence. About 30% of cases were in the operable stages I and II. With rising age, the proportion of the advanced stages III and IV increases. No real progress as made in early diagnosis of stomach cancer as measured by stage distribution during observation period. Patient's delay from first symptom to first visit was shorter than one month in 40%, physician's delay from first visit to correct diagnosis was shorter than one month in 54%. 15% of patients were treated within one month after first symptom and 47% within three months. There was no correlation between duration of history and percentage of early stages. When observation periods 1955 to 1959, 1960-1964, 1965-1969 and 1973 are compared, we find an increase in old patients (75+ years), a decrease of localized stages I + II, and a decrease in resection rate. Therefore, a decrease in survival rates is to be expected. Crude 5-year survival rate was 6.4% (1955-1959) and 6.2% (1960-1964). When we compare data from Berlin with observations in the Region of Erfurt and in Birmingham Region, the situation of detection and treatment of stomach cancer in Berlin seems to be somewhat better. Finally, some suggestions for the improvement of control of stomach cancer are made.

Adult↗
PubMed1976

[Bronchial cancer in Berlin, capital of the G.D.R. 2. communication. lung cancer detection between 1955 and 1973 (author's transl)].

In Berlin, capital of the G.D.R., more than 8,600 cases of bronchial cancer were observed in the period 1955 to 1969 and in 1973/4. Number of cases has increased from one 5-years period to the following period. Incidence of lung cancer in men increased especially in higher age groups whereas in female a rising incidence can be seen in all age groups. Duration of history is no good measure of health behaviour and of diagnostic quality. Distribution of clinical stages gives reliable information on the situation of detection. With rising age, the proportion of advanced stages increases. Stage distribution has not changed during the observation period and no measurable progress towards earlier detection of lung cancer has been achieved. In the same time, proportion of elderly lung cancer patients rose considerably and the chances of radical surgical treatment grew worse. Nevertheless the resection rate has increased. It seems that the quality of specialized surgical care has made some progress. Some conclusions can be drawn for cancer control: Prophylactic examinations are to be concentrated on high risk groups. Patients with suspicion of lung cancer shall be admitted to the specialist without delay. Development of nonsurgical methods of therapy for cancer of the lung is an important goal.

Adult↗
PubMed1975

Penetration of penicillin into human phagocytes containing gonococci.

Human phagocytes that had ingested gonococci were incubated with increasing concentrations of penicillin in fresh human serum. Viable counts on phagocyte deposits before and after incubation indicated penicillin penetration at high concentrations but not at lower concentrations which were sufficient to kill extracellular organisms. With lower concentrations significant intracellular survival of gonococci occurred.

Gonorrhea↗
PubMed1975

[Malignant neoplasms of colon and rectum in Berlin, capital of the G.D.R., 1960--1969 (author's transl)].

The situation of detection and treatment of colonic and rectal cancer in the capital of the G.D.R. Berlin is described for the period 1960--1969 and analyzed in comparison to other periods and regions. This study is based on the regional cancer registry and therefore free of the selection bias in clinical statistics. In the ten year period, 3855 new cases were registered (colon 2158, rectum 1697). The proportion of old patients is high, 66 percent were 65 years and older, 28% 75 and more years old. About 41% of patients seek medical advice within four weeks after first symptoms and about 60 percent of cancers were treated within one month after first consultation. The locaized stages I and II amounted to 46 percent of cases. There was only loose relation between duration of history and stage of disease. In nearly 39% of cases radical operation was performed and 27% were not treated by surgery. 5-year survival rates of colonic and rectal cancer in the period 1960--1964 amounted to 12% for all stages irrespeitive of method of treatment and 31% for patients after radical surgery. Survival rates depend on stage, on mode of treatment and on age. In the period from 1955 to 1973, proportion of old patients increased, distribution of stages remained nearly constant but proportion of cases radically operated on increased by 3%. Comparison of the regions of Berlin and Erfurt showed only small differences. Compared with international reports, survival rate is very low in Berlin, presumably due to complete registration of new cases and high number of very old people with colonic and rectal cancer.

Adult↗