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Biomedical subjects

B Krebs

Publications and source records attributed to B Krebs.

At least 91 records · Page 5Linked to original sources
PubMed1986

Ovarian function during aflatoxin B1-induced hepatocarcinogenesis in the rat.

Study of the endocrine status, which is often disturbed during hepatocarcinogenesis, is particularly valuable because gonadal function and hormone production regulate hepatic metabolism of the carcinogen. Sex steroids can even promote carcinogenesis. After aflatoxin B1 induction of liver carcinogenesis in adult female Sprague Dawley rats, livers were examined by histology, fluorescence microscopy of the carcinogen and its metabolites, and alphafetoprotein (AFP) assays. Ovarian activity was assessed, and both progesterone and estradiol levels were determined. Administration of a diet containing 10.32% total protein plus 2 ppm aflatoxin B1 was observed to prevent development of liver tumors during the 300 day study period. This finding is especially interesting for the study of populations suffering from malnutrition and exposed to dietary carcinogens. Under study conditions, aflatoxin B1 did not cause elevation of AFP levels, as occurs with other hepatotoxic substances. This absence of a rise in AFP despite liver alterations explains the surprising lack of ovarian modifications. In other experiments, AFP has been shown to cause genital function blockade which leads to reduced levels of hormonal promoters, for example during N2 fluorenylacetamide carcinogenesis. The endocrine reaction implicated in the development of tumors during carcinogenesis thus appears closely related to the nature of the carcinogen, AFP production, and the composition of the diet.

2-Acetylaminofluorene↗
PubMed1986

[Comparative study of 3 markers in ovarian cancer: CA 125, CA 19,9 and CEA].

CA 125 is today the best tumour marker to follow up the evolution of epithelial cancers of the ovary where it is elevated in about 80% of cases (as compared with a positive finding in only 20% for CEA and CA 19,9): it is no use as a screening test, it does reflect the quality of the first debulking operation, it makes it possible to follow the clinical evolution of the disease and thus to modify the adjuvant treatment, it helps to indicate whether a second look operation should be carried out; but it does not dispense altogether with the second look operation because even when CA 125 returns to normal the disease is sometimes still not eradicated, finally, it gives an opportunity to look early for any recurrences.

Antigens, Neoplasm↗
PubMed1985

Antibiotic prophylaxis in lower limb amputation.

We have prospectively studied the effect of 1-day prophylactic antibiotic therapy in lower-limb amputation for ischaemia. Twenty-seven patients were treated with Meticillin 1 g X 4 intravenously on the day of operation; 23 control patients did not receive any antibiotics. Eight patients in the control group had postoperative wound infections compared to none in the Meticillin group. Seven patients were re-amputated because of infection. Preoperatively, Staphylococcus aureus was isolated in 5/8 of the patients in the Meticillin and 6/8 in the control group. In the postoperatively infected stumps, S. aureus occurred in 6/8 of the patients in the control group, and one patient developed gas gangrene.

Aged↗
PubMed1984

High-performance liquid chromatographic investigations on the time-dependent reaction of cis-Pt(NH3)2Cl2, Pt(en)Cl2 and Pt(pn)Cl2 with RNA fragments.

The reaction of three platinum compounds, Pt(NH3)2Cl2, Pt(en)Cl2 and Pt(pn)Cl2 with nucleic acid fragments (Ade, Gua; GpG, GpA and ApA), both reactants (1:1, 1 X 10(-2) M; 1 X 10(-3) M) being dissolved in water, has been studied. UV measurements have been used to characterize the products. Kinetics and adduct formation in the nucleoside-Pt compound system were studied by reversed-phase high-performance liquid chromatography [gradient 0-30% methanol in 30 min, ammonium acetate buffer (0.1 M) at pH 4.25] at fixed intervals of time and the product formation was examined by measuring the peak heights. After 10 h, the reaction was complete for guanosine and showed a steady state for adenosine. The increasing lipophilicity in the sequence of the platinum compounds resulted in a shift to longer retention times.

Adenosine↗
PubMed1984

Non-painful phantom limb phenomena in amputees: incidence, clinical characteristics and temporal course.

58 patients undergoing limb amputation mainly because of peripheral vascular disease were interviewed by means of a standard questionnaire and examined 8 days, 6 months and 2 years after limb amputation regarding non-painful phantom limb phenomena. During the follow-up period, 41% of patients died. The incidence of phantom limb 8 days, 6 months and 2 years after limb loss was 84%, 90% and 71%, respectively. Phantom limb phenomena changed within the first half year after amputation from a mainly proximal and distal distribution to a mainly distal localized sensation. While approximately 3/4 of patients with phantom limb had kinaesthetic sensations in the limb (i.e. feeling of length, volume or other spatial sensation) during the first 6 months after amputation, less than 50% of patients had this later in the course; 30% of patients noticed a clear shortening of the phantom limb during the follow-up period. While the incidence of phantom limb did not decrease during the follow-up period, both the duration and frequency of phantom limb phenomena declined significantly. The distribution of non-painful and painful phantom limb did not differ significantly from each other. The present findings suggest that mechanisms both in periphery, spinal cord and brain participate in generating the phantom limb percept.

Adult↗
PubMed1984

Simultaneous dorsal dislocation of both interphalangeal joints in a finger.

Following simultaneous dorsal dislocation of both interphalangeal joints of a finger, attention must be paid to the risk of a long period of recovery because of the severity of the lesion. Approximately one year after such an accident to a footballer arthrodesis was performed on the proximal interphalangeal joint, as the patient was still suffering from constant pain in the finger.

Adult↗
PubMed1984

[Alpha-fetoprotein and blockade of the sexual cycle].

During chemical hepatocarcinogenesis by N-2 fluorenylacetamide in adult female Rats, vaginal cycle alterations were observed after 30 days of carcinogenic diet, and a blocking at the metestrus stage appeared from the 70th day. This may be explained by the very low serum progesterone level prevailing after the 50th day. An important drop in ovary weight was also noticed; together with the blocking of follicular maturation and ovulation leading to a marked follicular atresia. Simultaneously, alpha-fetoprotein (AFP) seems to interact in the lowering of progesterone level, and AFP was found ten times higher in the serum of treated animals than in controls. AFP was localized in degenerative oocyte cytoplasm by immunofluorescence in the treated animals, but not in the controls. In conclusion, a blocking role of AFP on genital cycles and a relationship between AFP and follicular atresia are suggested.

2-Acetylaminofluorene↗
PubMed1983

Blood flow in the juvenile hip in relation to changes of the intraarticular pressure. An experimental investigation in dogs.

The blood flow in the hip joint of puppies was studied by means of the microsphere technique. The flow was determined before, during and after intraarticular pressure increase. A venous tamponade of 50 mmHg resulted in a significantly reduced flow in the femoral head and after an arterial tamponade of 150 mmHg the flow almost ceased. The proximal femoral metaphysis, the acetabulum and the hip joint capsule, on the contrary, showed varying degrees of flow increase. It is suggested that the significantly increased blood flow in the hip joint capsule during the intraarticular pressure increase of 50 mmHg and 150 mmHg is caused by an autoregulatory mechanism tending to restore the blood flow in the suffering femoral head. The demonstrated disturbance of the circulation in the juvenile femoral head after venous tamponade supports the theory that synovitis may be the basic mechanism in the production of Calvé-Legg-Perthes' disease.

Acetabulum↗
PubMed1983

[Methodological error in clinical lysozyme determinations].

In 152 sera and 40 synovial fluids of 192 patients from 3 different diagnostic groups the level of muramidase was studied comparatively with the lysoplate method. Despite the similar correlations of mean values and standard deviations of the results in the single groups, en detail these are significantly different. With an increasing mean value of 1 U (mg/l) the standard deviation is elevated by 0.1-0.25 U, for an elevation of s by 1 U mean varied between 3.8 and 9.7 U. This might be of interest for the clinical interpretation esp. of low muramidase values.

Humans↗
PubMed1982

Influence of the hip joint position on the intraosseous pressures in the juxta-articular bones. An experimental investigation in dogs.

In 6 mongrel dogs (eleven hips) the intraosseous pressure was measured in the femoral head as well as acetabulum in various hip joint positions. The control position for the measurements was 90 degrees flexion in which the pressures were found low and stable. The intraosseous pressure in both locations were subjected to consistent pronounced variations when the joint position was altered. In the femoral head, significant pressure increases (p less than or equal to 0.01) were found in maximal extension, maximal flexion, maximal adduction, 90 degrees external rotation, 45 degrees internal rotation, and maximal internal rotation. The pressure in acetabulum rose significantly in maximum flexion, 45 degrees internal rotation, and maximum internal rotation, whereas the pressure increase in maximal extension and maximum adduction was consistent but not significant. The pressure increase is most probably caused by inhibition of the venous drainage changing the bone hemodynamics in the juxta-articular bones. A complete obstruction of venous drainage was not observed since the intraosseous pressure in none of the measurements reached the level of the arterial pressure.

Acetabulum↗
PubMed1982

Intra-articular fractures of the distal tibia.

In a study of 23 intra-articular fractures of the distal tibia of which 18 were re-examined after an average follow-up period of 5.4 years, two major fracture patterns were identified: type A, a rotational pattern, caused by low energy trauma and type B, a compressive fracture pattern caused by high energy trauma. Type B fractures could be divided into three subgroups: 1) An isolated fracture of the anterior or posterior margin of the distal tibia, 2) an extra-articular comminuted fracture with extension into the ankle joint and 3) a comminuted intra-articular fracture. When the initial displacement and comminution were severe or the reduction was not complete, the final results of the comminuted intra-articular fractures were not acceptable. The incidence of osteoarthritis was highest in the group of comminuted intra-articular fractures. The extra-articular comminuted fractures seemed to have a better prognosis as indicated by the final clinical results, including the occurrence of osteoarthritis. It is clear from this study that comminuted intra-articular fractures should not be treated by primary operation. All fractures treated non-operatively had acceptable final clinical results.

Adult↗
PubMed1982

Role of alpha-fetoprotein (AFP) in the regulation of ovarian activity during hepatocarcinogenesis and post-natal development.

N-fluorenylacetamide produces an augmentation of serum AFP which is accompanied by a drastic decrease of ovarian activity. A passive augmentation of the AFP level of adult rats, produced by injection of this protein provokes the same phenomenon: i.e. a decrease of follicular maturation, a decrease number of corpora lutea and finally a drop in the plasma progesterone level. The study of ovarian post-natal development shows that ovarian maturity occurs on the 35th day of life when AFP level reaches its adult serum concentration. These facts support the hypothesis that AFP plays a role in the regulation of ovaries during the sexual maturation of the female rat.

Animals↗