Search PubMed⌕ Search

Biomedical subjects

K Hoffmann

Publications and source records attributed to K Hoffmann.

At least 253 records · Page 14Linked to original sources
PubMed1991

Statistical evaluation of the evidential value of human hairs possibly coming from multiple sources.

A concept of the mathematical evaluation of human hair evidence is derived. This concept can be realized in a special computer program, the output of which is an incrimination probability. The problems of not knowing the true number of sources and the correct partition of hairs corresponding to their sources are solved from the point of view of avoiding an unjustified incrimination.

Forensic Medicine↗
PubMed1990

Long-term effects of acetazolamide and sodium chloride loading on cisplatin nephrotoxicity in the rat.

The protective effect of acetazolamide or sodium chloride loading on cisplatin nephrotoxicity was investigated in rats. After a single dose of cisplatin (5 mg kg-1 i.p.) kidney function was studied after 5, 28 and 84 days. Acetazolamide (75 mg kg-1 i.p.) was administered as a single dose prior (30 min) to the cisplatin injection. By the time of cisplatin administration, the rats were sodium depleted except the sodium-loaded group. Five days after the cisplatin administration all rats received a regular rat chow for the rest of the experiment. Cisplatin alone caused renal failure that could be observed for up to 12 weeks (ClCr 0.32 +/- 0.13 vs. 0.62 +/- 0.06 ml min-1 x 100 g BW-1) with polyuria (UVol 41.2 +/- 4.5 vs. 18.4 +/- 4.6 ml 24 h-1). Pretreatment with acetazolamide was the most protective manoeuvre tested. Five days after cisplatin, kidney function was significantly better than in rats treated with cisplatin alone (ClCr 0.21 +/- 0.06 vs. 0.03 +/- 0.01 ml min-1 x 100 g BW-1), after 28 days the only sign of nephrotoxicity was polyuria (UVol 28.9 +/- 3.7 vs. 19.0 +/- 2.6 ml 24 h-1) after 84 days no differences could be observed at all. Sodium chloride loading was less protective on cisplatin nephrotoxicity. Impaired renal function could still be observed after 12 weeks (ClCr 0.41 +/- 0.05 vs. 0.62 +/- 0.06 ml min-1 x 100 g BW-1) with no difference in comparison with the rats treated with cisplatin alone. However, since 12 rats died in the group having received cisplatin alone and only one rat in the high-salt group, sodium chloride loading is regarded as being advantageous over sodium depletion on cisplatin nephrotoxicity.

Acetazolamide↗
PubMed1990

Distribution pattern of testicular sulphydryloxidase immuno-activity in the djungarian hamster (Phodopus sungorus) during photoperiodically induced involution and recrudescence.

The distribution pattern of testicular sulphydryloxidase (SOx) immuno-activity was investigated in the djungarian hamster during photoperiodically induced testicular involution and recrudescence. SOx immuno-activity, indicating functional integrity of labelled cells, did not change in pachytene spermatocytes and spermatids as long as these cells were present in the seminiferous epithelium. Its disappearance coincided with the degeneration of spermatocytes in phases IV and V of involution and reappeared during recrudescence, when the first spermatogenic wave had reached the pachytene stage. In tubules at phase VI of involution (showing maximal regression), the apical cytoplasm of Sertoli cells showed immuno-activity. This immuno-activity disappeared during recrudescence prior to the differentiation of pachytene spermatocytes. Changes in SOx immuno-activity resembled those of lactate dehydrogenase-X (LDH-X) in photo-inhibited testes or during puberty, indicating a close functional relationship which still remains to be elucidated. The data suggest that the hamster exposed to different photoperiods can be used as a suitable model to study the relationship between testicular morphology and function in different states of gonadal activity.

Animals↗
PubMed1990

[Use of DNA polymorphism in forensic paternity evaluation].

Problematical paternity cases were additionally subjected to DNA-polymorphism analysis. 5 cases are reported, focusing on problems due to, 'silent' allele transmittance, relatively low probability for paternity, obvious occurrence of the extremely rare Rh gene complex CWc, involvement of brothers as putative fathers, non-paternity of a man although his W-value was 99.975%. The aim of this paper is to demonstrate the need for DNA-polymorphism analysis, if conventional blood group tests do not lead to a clear-cut decision. Extended typing of conventional blood group polymorphisms (except HLA) cannot compete with highly polymorphic DNA loci.

Adult↗
PubMed1990

[1989 Bochum health education program for malignant melanoma].

The incidence rate of all skin cancer forms has been increasing during the last few decades. The incidence of malignant melanoma is important due to its very high malignancy and its growing spread especially among young patients. Malignant melanoma is mainly observed on the external skin and is therefore well suited for screening methods. During a campaign in the city of Bochum, 1226 patients were examined. A total of 9 malignant melanomas and 10 basal cell carcinomas were discovered. The statistical data show that most of the patients could be motivated to participate by regional media and not by supraregional media. The wide acceptance of our prevention week shows that prevention campaigns are feasible, important and necessary.

Adolescent↗
PubMed1990

[Digital 20 MHz sonography of basalioma in the B-scan].

Digital 20 MHz b-scan sonography is a new non-invasive tool in dermatological routine diagnostics. The 20-MHz linear scanner employed in this study has a signal penetration of 7 mm, a lateral resolution of 200 microns and an axial resolution of 80 microns. Seventy-five basal cell carcinomas were examined by ultrasound. An exact correlation of histological slides and sonographic images allowed us to explain the sonographic phenomena of basal cell carcinoma (BC). BCs exhibit a well-defined area with poor echoes; they sometimes even show a total loss of reflection. In the tumor parenchyma inhomogenously distributed internal echos were found. Below the tumor post-tumoral enhancement of the signal reflection is common (depending on the type of BC -up to 70%). Our results prove that digital 20 MHz ultrasonic imaging systems are well suited for studying the extension, thickness and tissue texture of basal cell carcinoma.

Adult↗
PubMed1990

Fenestrated capillaries in the ventral sebaceous gland of the Djungarian hamster, Phodopus sungorus.

The ventral sebaceous gland of the Djungarian hamster is a macroscopically visible organ situated in the midventral area of the abdominal wall. It consists of densely packed acini arranged in lobules with common excretory ducts. The rich vascular network of the gland is characterized by fenestrated capillaries. Fenestrated endothelium has not yet been reported as a characteristic and regular finding within sebaceous glands. Results are discussed with regard to proliferation rate of sebocytes and the demand of fluid and nutrient supply.

Animals↗
PubMed1990

[Serologic studies in the diagnosis of pneumonia].

The importance of serological determination procedures for the diagnosis of pathogens was investigated in 207 episodes of pneumonia. The pathogenic organisms were detected in 138 cases; in 40 cases serological analysis helped to establish the diagnosis, while in 11 cases of pneumonia, the diagnosis was possible only with serology. The organisms most commonly found by serological investigations were Cytomegalovirus (n = 10), Aspergillus fumigatus (n = 7), and the influenza B virus (n = 7). Multiple infections, usually triggered by bacterial pathogens, were found in 48% of the cases of pneumonia with serological evidence of pathogens. In 71 episodes of pneumonia, the patients were immunosuppressed; in 11 cases, the causative organism was detected serologically.

Adult↗
PubMed1990

[Pneumonia in patients with and without immunosuppression--value of bronchoscopic biopsy technics for the detection of pathogens].

Bronchoscopic diagnosis was performed in 91 patients with 100 episodes of fresh pneumonia. In already existing immunosuppression (n = 51, Group A) pathogens were most frequently identified via bronchoalveolar lavage (70%); in patients without immunosuppression (n = 49, Group B) the identification quota in respect of the central bronchial secretion (53%) and bronchoalveolar lavage (47%) were comparable. In Group A the most frequently occurring pathogens were Pneumocysti carinii (n = 18) and Aspergillus fumigatus (n = 7), in Group B Streptococcus pneumoniae (n = 8) and Staphylococcus aureus (n = 7).

Adult↗
PubMed1989

[Digital 20 mhz sonography of the skin in preoperative diagnosis].

B-scan 20 MHz ultrasonography is a new non-invasive technique to study the skin architecture. In a study on 236 patients, we showed that ultrasonic investigations can provide an efficient means to determine the thickness and extension of tumors. In addition, ultrasound may help make the differential diagnosis. This method is particularly accurate in the measurement of tumor thickness of malignant melanomas and the determination of depth and width of basal cell carcinomas. Furthermore, b-scan ultrasound offers additional criteria for the differential diagnosis of pigmented skin lesions. We believe, therefore, that high frequency ultrasound in vivo can definitely improve surgical planning.

Basal Cell Carcinoma↗
PubMed1989

[Cryosurgery of basalioma. Results of a retrospective study. Histologic study of the cryogenic lesion].

Cryosurgery is considered an alternative method in the treatment of basal cell carcinomas of the face and usually leads to excellent functional and cosmetic results. This technique can be modified depending on the number of freeze-thaw cycles. According to our experiences (220 cases), a single freeze-thaw cycle is indicated for those basal cell carcinomas which do not go beyond the middle dermis; these cases were characterized by fast wound healing and a very satisfying cosmetic outcome. Invasion of the lower dermis as well as basal cell carcinomas in skin folds require repeated freeze-thaw cycles. The specific mode of cryosurgical treatment, therefore, has to be differentiated depending on the site of the tumor and its depth of invasion.

Basal Cell Carcinoma↗
PubMed1989

Photoperiodic influence on the innervation of the ductus epididymidis and ductus deferens of the Djungarian hamster, Phodopus sungorus: electron-microscopic and biochemical results.

The influence of long (light:dark 16:8) and short (light:dark 8:16) photoperiods on the autonomic innervation of the ductus epididymidis and the ductus deferens of Phodopus sungorus was studied using electron microscopy with morphometric analyses, and biochemical methods. At short photoperiods, only the large smooth muscle cells in the ductus deferens became atrophic, the number of mainly adrenergic varicosities in the smooth muscle layer decreased, and the mean distance between varicosity and smooth muscle cells increased. The content of noradrenaline was determined by high-performance liquid chromatography with electrochemical detection. For the ductus deferens, the noradrenaline content was reduced at LD 8:16 to less than 10% of the initial value. Short photoperiods are proposed to influence only the adrenergic innervation of the large smooth muscle cells of the ductus deferens. These cells are believed to exert a trophic influence on their nerves.

Adrenergic Fibers↗
PubMed1989

Ultrastructural localization of thyrotropin (TSH)-like immunoreactivity in specific secretory cells of the hypophyseal pars tuberalis in the Djungarian hamster, Phodopus sungorus.

Specific secretory cells in the hypophyseal pars tuberalis of Djungarian hamsters maintained under different photoperiods were investigated immunocytochemically by means of the colloidal gold technique using antibodies against rat thyrotropin (TSH). Secretory cells of animals kept under long photoperiods (LD16:8) showed positive staining of secretory granules (diameters 90-130 nm), whereas other intracellular structures were free of immunoreactivity. In animals kept under short photoperiods (LD8:16) secretory cells displayed increased numbers of secretory granules, but these organelles were devoid of immunoreactivity. In contrast, immunoreactivity of thyrotropes in the pars distalis did not differ between the two groups of animals investigated. The present results confirm earlier light-microscopical studies that in the pars tuberalis specific secretory, cells show TSH-like immunoreactivity; however, they differ in their reactivity pattern from classical thyrotropes in the pars distalis.

Animals↗
PubMed1989

Differential effects of follicle-stimulating hormone and luteinizing hormone on Leydig cell function and restoration of spermatogenesis in hypophysectomized and photoinhibited Djungarian hamsters (Phodopus sungorus).

Effects of pure human follicle-stimulating hormone (hFSH) and ovine luteinizing hormone (oLH) on testicular function were investigated in long-term hypophysectomized or photoinhibited Djungarian hamsters. hFSH (5 IU) or oLH (5 micrograms) or a combination of FSH and LH (5 IU and 5 micrograms, respectively) were injected s.c. twice daily for 7 days to hypophysectomized and photoinhibited hamsters. Other photoinhibited hamsters were treated for 14 and 21 days with FSH and LH (3 IU and 3 micrograms, respectively) in a similar way. LH alone had little, if any, effect on testicular weights; FSH, when injected alone or in combination with LH (FSH/LH), caused a significant increase in testes weights at each time point. On the other hand, LH or FSH/LH, but not FSH alone, caused a significant increase in the accessory organ weights. FSH had no effect on intratesticular testosterone (T) or on 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) activity but enhanced the in vitro response of interstitial cells to hCG. LH and FSH/LH had pronounced effects on intratesticular T, 3 beta-HSD activity, and in vitro response of interstitial cells to human chorionic gonadotropin. Treatment with FSH or FSH/LH caused regrowth of the testis and restoration of tubular lumen and tubular diameter and restored complete spermatogenesis. However, LH had little effect on spermatogenesis in spite of increased intratesticular and peripheral T levels. These results indicate that although LH can cause a full redifferentiation of Leydig cells in photoinhibited hamsters, it has only minor effects on tubular function. On the other hand, FSH alone induces full restoration of tubular function in these animals and has no direct effect on Leydig cell steroidogenesis, but may enhance the Leydig cell responsiveness to LH.

3-Hydroxysteroid Dehydrogenases↗