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Biomedical subjects

R Nagel

Publications and source records attributed to R Nagel.

At least 91 records · Page 5Linked to original sources
PubMed1990

Toxicity of lindane, atrazine, and deltamethrin to early life stages of zebrafish (Brachydanio rerio).

Fertilized eggs of zebrafish were exposed under flow-through conditions to several concentrations of the following pesticides: lindane 40, 80, 110, 130, and 150 micrograms/liter; atrazine 300, 1300, and 9100 micrograms/liter; deltamethrin 0.5, 0.8, and 1.2 micrograms/liter. Hatching, abnormalities in development (external deformations, edema, etc.), and mortality were recorded over a period of 35 days. At the end of the experiment, the body lengths of the fish were measured. Survival of juvenile fish after 35 days was reduced by increasing concentrations of all xenobiotics tested: lindane enhanced the mortality from 110 micrograms/liter and atrazine from 1300 micrograms/liter, and deltamethrin showed an effect even at the lowest test concentration (0.5 micrograms/liter). Other parameters were affected differently: hatching rate was reduced only by deltamethrin (from 0.8 micrograms/liter): lindane caused a decrease in growth (40 micrograms/liter) but had no effect on the other parameters. Atrazine increased the number of deformations and edema (1300 micrograms/liter) but did not influence hatching rate and growth. The sensitivity of the early life stages to the pesticides was compared with acute toxicity data (LC50) of adult zebrafish. The early life stages were less sensitive to lindane (118 versus 75 micrograms/liter), whereas in the case of atrazine (1300 versus 37,000 micrograms/liter) and deltamethrin (0.5 versus 2 micrograms/liter; 0.5 micrograms/liter was the lowest concentration tested) larvae were more sensitive.

Abnormalities, Drug-Induced↗
PubMed1990

Hepatic steatosis in zebra fish (Brachydanio rerio) induced by long-term exposure to gamma-hexachlorocyclohexane.

In a full life cycle test, newly hatched eggs of zebra fish, Brachydanio rerio, were reared to sexual maturity under continuous exposure to 40, 80, 110, 130, and 150 micrograms/liter lindane, gamma-hexachlorocyclohexane. The effects of lindane were investigated by recording behavior and survival of the F0- and F1-generation as well as morphological alterations in liver ultrastructure of F0. Changes in peroxisomes were visualized by cytochemical staining for catalase activity with diaminobenzidine. Whereas behavioral changes can already be observed at 40 micrograms/liter, survival and number of eggs in F0 as well as survival and growth of F1 are unaffected by up to 80 micrograms/liter lindane. At concentrations greater than or equal to 110 micrograms/liter, survival of larvae is reduced already after 35 days, and mortality is 100% after 3 months. From 40 micrograms/liter, liver ultrastructure displays a microvesicular fatty vacuolation (steatosis) characterized by lipid deposition within the cisternae of the RER. At 40 micrograms/liter, this highly specific pathological change is accompanied by accumulation of hepatic macrovesicular triglyceride droplets, glycogen depletion, and the occurrence of club-shaped mitochondria. Additional alterations at 80 micrograms/liter comprise proliferation of SER in males and progressive fractionation of RER in females, stacking of club-shaped mitochondria, a conspicuous decrease in peroxisomal catalase activity, infiltration of macrophages into the liver parenchyma, and a significant stimulation of hepatocytic mitosis. Among several substances tested so far in zebra fish (4-nitrophenol, 4-chloroaniline 3,4-dichloroaniline, atrazine, lindane), lindane is the only compound inducing behavioral changes and hepatic steatosis in conjunction with a reduction in fertility. With regard to the relative sensitivity of the methods applied, behavioral and cytological studies appear more responsive to lindane exposure than survival studies.

Animals↗
PubMed1990

Nuclear DNA analysis: the relevance of ploidy, DNA heterogeneity and phases of the cell cycle in 329 patients with prostatic carcinoma. A study on a follow-up of eight years.

The ploidy, DNA heterogeneity and the phases of the cell cycle of the tumor were analyzed, by means of single-cell DNA cytophotometry, in 329 patients with locally advanced prostatic carcinoma to find out and establish prognostic factors apart from those already known (stage, grade). Follow-up periods ranged from 1 to 9 years. 253 (76.8%) of the 329 patients had carcinoma stage T3 Nx M0, and 76 of them (23.1%) had carcinoma stage T3/T4 N2-4 M1. 11.8% of the patients showed a cytological grade of malignancy I, while 64.3% had grade II carcinoma and 23.8% had grade III carcinoma. Single-cell DNA cytophotometry demonstrated aneuploidy rates of up to 71% and diploidy rates of up to 23.8% for the higher grades of malignancy, i.e. grades II and III, whereas the diploidy rate established for grade I was 68% and the respective aneuploidy rate was 21%. These differences are significant (p less than 0.001). There was a significant correlation between the results of DNA cytophotometry and the clinical course of the disease. Only 3 (3.7%) of the patients with diploid tumor cell nuclei developed metastases and local tumor progression within 8 years, whereas patients with aneuploid tumor cell nuclei showed metastases and local tumor progression within 8-22 months. These patients died of carcinoma after an average 18 months following primary diagnosis.

Aged↗
PubMed1990

Assessment of a brief interviewing course using the Helping Relationship Inventory: an interviewing course assessment.

A brief second year interviewing course consisting of 9 hours of small group meetings was evaluated by administering the Helping Relationship Inventory (HRI). Other studies have used the HRI to assess longer interviewing courses that included both small groups and large class lectures. The purpose of this study was to use the HRI to see if objective improvement in communication skills could be found in this relatively brief interviewing course. One hundred and nine students, representing an 80% return rate, completed all questions on the HRI pre- and post-tests. Analysis of pre- and post-test data showed that students became significantly more understanding (p less than 0.0001) and significantly less 'supportive' or pacifying (p less than 0.0001) by the end of the course. There were no differences found on pre- and post-test HRI scores comparing males (n = 71) and females (n = 38). This study demonstrates that even brief small group interviewing courses can effect a positive change in students' communication skills.

Communication↗
PubMed1990

[The value of magnetic resonance tomography in the diagnosis of renal space-occupying lesions].

41 patients (45 renal tumours) were examined by magnetic resonance imaging to assess the value of the method and its use to specify renal tumours. Histological findings were available in 38 cases. The results of MRI were compared with the CT and ultrasound diagnosis and the histological findings. In 92.1% (35/38) the CT-diagnosis agree with the histological findings, the ultrasound in 76.3% (29/38) and the MRI in 84.2% (32/38). To specify renal tumours the diagnosis by CT-scan and ultrasound is sufficient.

Adult↗
PubMed1990

[The treatment of retroperitoneal fibrosis. Report of personal experience with 17 cases].

Between 1974 and 1988 17 patients with retroperitoneal fibrosis were seen in our hospital. 9 patients received medical and surgical treatment: first ureterolysis with intraperitoneal displacement following an immunosuppressive therapy. 6 patients received only immunosuppressive therapy. 1 patient only received surgical treatment. 1 patient showed spontaneous remission. The results of our study confirm that the combined surgical and medical treatment is a good therapy of retroperitoneal fibrosis. An effective treatment with immunosuppressive drug therapy alone is possible in well-chosen patients.

Adolescent↗
PubMed1989

Students' reactions as guides to course revisions.

Items on four course changes made in response to students' evaluations of a course on interviewing were rated higher by the 3 succeeding classes of students, indicating changes improved the students' perceptions of the course.

Attitude of Health Personnel↗
PubMed1988

Tumours of the renal pelvis and ureter. Observations in 170 patients.

A study was made of 170 patients with renal pelvis or ureteric tumours, 160 of whom underwent surgery between 1948 and 1981. The most important aetiological factor was chronic phenacetin abuse: 21.7% of 83 patients with renal pelvis tumours and 11.4% of those with ureteric tumours gave a history of phenacetin abuse. The latency periods ranged from 24 to 26 years. This is the first report of a relationship between abuse of analgesics and urothelial tumours from the Federal Republic of Germany.

Adolescent↗
PubMed1988

Prognostic relevance of ploidy and proliferative activity of renal cell carcinoma.

In 112 patients with renal cell carcinoma, the ploidy, DNA heterogeneity and the phases of the cell cycle occurring in the tumors were determined by means of single-cell DNA cytophotometry, in order to establish further prognostic factors in addition to the ones known so far (stage/grade). Patients with aneuploid tumors or tumors with more than one DNA frequency peak were found to have lymph node metastases intraoperatively and died earlier than patients with diploid tumors. Patients who had tumors with low proliferative activity survived longer than patients with highly proliferative tumor activity (p = 0.001).

Adult↗
PubMed1988

Treatment of locally advanced prostatic carcinoma with LHRH analogues: cytological, DNA-cytophotometrical, and clinical results.

From June 1, 1981 to December 31, 1985, 122 patients aged 54 to 83 years, with locally advanced prostatic carcinoma, were treated with buserelin. Nineteen of the patients received combined therapy with buserelin and androcur for the first 3 months. To control the response of the primary tumor to therapy, fine-needle aspiration biopsy of the prostate was made in all patients at 3-month intervals. Fifty-eight (76.3%) of 76 patients with locally advanced prostatic carcinoma, with or without bone metastases, who underwent buserelin therapy for periods of 12-54 months showed good to satisfactory regression grades in the primary tumor. Eighteen patients (23.7%) showed poor regression or none, established by cytological findings and the measure of DNA by means of single cell-scanning cytophotometry. In three of the 58 patients, tumor progression or bone metastases occurred despite favorable regression grade; these were the only cases in which there was a discrepancy between the clinical course of the disease and the grade of regression in the primary tumor. According to TNM classification, 68 of the 78 patients treated for 12-54 months were in stage T3 NX M0; eight were in stage T3/T4 NX M1. On the basis of our long-term studies, it can be stated that buserelin therapy induces positive therapy response in more than 75% of locally advanced, inoperable, primary prostatic carcinoma. The clinical castration caused by buserelin through selective suppression of gonadotrophic secretion in the pituitary gland is, as the term implies, no more effective than surgical castration. However, the gonadotrophin suppression induced by buserelin is reversible and spares the patient the psychic stress of orchiectomy. This is a decisive advantage in light of the fact that in 20-40% of patients with locally advanced primary prostatic carcinoma, the primary tumor is hormone-refractory, and surgical castration would prove unnecessary after all.

Aged↗
PubMed1987

Endoscopic intubated ureterotomy.

On the basis of our experience with 9 cases, endoscopic ureterotomy for ureteral stenoses represents an alternative to open reconstructive surgery. In cases of acquired ureteral stenoses, the transurethroureteral access appears to be the method of choice. In contrast to open surgery, particularly after previous operations, surgical trauma is minimal. A primary attempt at ureteroscopic ureterotomy is warranted, since it does not appear to pose any problems for open surgery should this prove necessary later.

Adult↗
PubMed1987

The metabolism of phenol and substituted phenols in zebra fish.

1. The metabolism of five phenols in zebra fish was studied after uptake from the medium. The results showed no qualitative differences to other Cyprinid fish species, only the oxidation rate seemed to be lower. 2. Phenyl glucuronide, phenyl sulphate, and quinol sulphate were identified as metabolites of phenol. 3. Identified metabolites of 2-cresol were 2-cresyl glucuronide, 2-cresyl sulphate, and 2-hydroxybenzoic acid in trace amounts. 4. Only the glucuronide and sulphate conjugates were detected as metabolites of 4-nitrophenol, 4-chlorophenol, and pentachlorophenol.

Animals↗
PubMed1985

Immunohistochemical and radioimmunological determination of beta-HCG and pregnancy-specific beta 1-protein in seminomas.

38 pure and 11 mixed seminomas were studied with the peroxidase-anti-peroxidase method for the presence of chorionic gonadotropin (beta-HCG) and pregnancy-specific beta 1-glycoprotein (SP1). HCG was found in 8 of 49 cases, SP1 in 5 of 49 cases in syncytial and mononuclear giant cells. The 5 pure seminomas with positive tumor markers appear to have no worse prognosis than pure seminomas without HCG or SP1 production. None of the seminomas was found to contain carcinoembryonic antigen or alpha-fetoprotein.

Chorionic Gonadotropin↗
PubMed1985

Immunohistochemical demonstration of tumor-associated antigens in prostatic carcinomas of various histological differentiations.

Prostate acid phosphatase (PAP), prostate-specific antigen (PSA), carcinoembryonic antigen (CEA) and keratin were determined immunohistochemically in paraffin sections from 64 prostatic carcinomas fixed in formalin according to the conventional method. The results obtained with PSA led to the correct diagnosis of prostatic carcinoma in 90.7% of the cases. 80.3% of the diagnoses obtained with PAP were correct. The intensity of the staining of the marker decreased with increasing differentiation. 3 utricular carcinomas were positive for PAP and PSA. CEA and keratin may be considered unspecific tumor markers only. However, metaplastic squamous epithelium from poorly differentiated carcinomas was always positive for keratin. PAP and PSA are also suitable for differentiating between tumors of prostatic and nonprostatic origin and could thus be successfully used to determine immunohistochemically the histogenesis of 15 invasive, poorly differentiated carcinomas of the prostate and bladder. PSA again proved to be a more specific epithelial marker than PAP.

Acid Phosphatase↗