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Biomedical subjects

K Miller

Publications and source records attributed to K Miller.

At least 289 records · Page 16Linked to original sources
PubMed1996

Successful transplantation of human hepatoblastoma into immunodeficient mice.

Six hepatoblastomas (HBs) from pediatric patients were transplanted into immunodeficient NMRI nu/nu mice. Cells from two fetal HBs did not develop tumors. In contrast, xenografts derived from three nonpretreated HBs and one HB after three courses of chemotherapy, all comprising embryonal cells, showed growth after 8 to 10 weeks. The take rates of HB varied from 60% to 90% (mean, 80%). Histologically, they resembled their originals in the pattern of fetal and embryonal differentiated areas and contained hematopoietic foci. The tumors produced high levels of alpha-feto-protein in the patients and the animals. In contrast to the patients, tumor-bearing mice did not display elevated platelet counts. During serial grafting, growth rates of the tumors gradually increased, and hematopoiesis was no longer detectable; however, histologically, a dedifferentiation could not be clearly identified. The addition of viable human or murine fibroblasts to inoculated cells of three nude mouse HBs resulted in a significant increase in the growth rate of all tumors and reappearance of hematopoiesis in three of the examined 10 xenografts of one HB. The authors conclude that HB xenografts in immunodeficient mice are a feasible in vivo model for studies of the biological behavior of this tumor.

Animals↗
PubMed1996

Population and women's reproductive health: an international perspective.

This paper gives a brief overview of current world population or demographic issues, followed by a discussion of the ICPD proceedings and various notable aspects of the ICPD Programme of Action. It then focuses on six of the most pressing reproductive health concerns facing women today: gender inequalities, access to contraceptive services, sexually transmitted diseases (including HIV), maternal mortality, unsafe abortion, and adolescent pregnancy. Because the ICPD Programme of Action is intended to have far-reaching consequences for each of these issues, it is taken as a focal point of analysis.

Abortion, Legal↗
PubMed1996

Transplantation in autosomal dominant polycystic kidney disease without nephrectomy.

Some transplantation centers still suggest nephrectomy in patients with autosomal dominant polycystic kidney disease (ADPKD) before kidney transplantation at least in selected cases. We wanted to learn whether prior nephrectomy is beneficial. The outcome of kidney transplantation in 47 consecutive ADPKD patients without prior nephrectomy was compared with that in matched controls with respect to complications of ADPKD. Although ADPKD patients were older than controls (mean, 50.1 vs. 40.3 years), there was no statistically significant difference in 1- and 5-year allograft survival between ADPKD patients and controls: 76.6 and 68.0%, respectively, in ADPKD patients, and 83.9 and 56.3% in controls. After a mean follow-up of 66.5 months 3 patients with ADPKD had cyst infections and were managed with antibiotics. Two patients had episodes of hematuria; neither required invasive therapy. There was no renal malignancy and clinical sign of urolithiasis in any patient. No posttransplantation nephrectomy was required. With only few indications remaining, there is no rationale for routine pretransplantation nephrectomy in patients with ADPKD.

Adult↗
PubMed1996

Ultrasound and soft-tissue radiography to monitor local interferon-alpha 2B treatment in Peyronie's disease.

PURPOSE: We attempted to assess objectively the response of Peyronie's disease plaques to local interferon-alpha 2B. MATERIAL AND METHODS: Twenty patients were treated with 5 local injections of 1 million units of IFN-alpha 2B into a single designated plaque. Before treatment, and 4 weeks and 6 months after treatment, the plaques were examined ultrasonographically. Each time, a histogram profile was performed. All patients also underwent soft-tissue radiography in 2 planes using the mammography technique before and 6 months after treatment. RESULTS: We found that with ultrasonography the plaques could be classified into 3 groups depending on degree of calcification, from nil to complete. Radiography detected calcifications better than ultrasonography but failed to detect plaques without calcification. The degree of calcification was negatively correlated with the response to treatment, since noncalcified plaques responded best, while fully calcified plaques failed to respond. CONCLUSION: In Peyronie's disease, ultrasonography is an important tool for non-invasive monitoring treatment response and for preselecting patients for medical treatment.

Follow-Up Studies↗
PubMed1996

Adjustments and Leak Detection of the Adjustable Silicone Gastric Band (ASGB) and Lap-Bandtrade mark Adjustable Gastric Band (LAGB) System.

BACKGROUND: The detection of a leakage in the system of the adjustable silicone gastric band (ASGB) may be difficult. Gastrografin injection into the port should be avoided because it acts like a glue and blocks the system. METHODS: A syringe containing saline and a syringe containing Thallium-201 chloride is connected to the 4-way stopcock which is connected to the needle. The needle is pushed into the port. The position is confirmed by injection and aspiration of saline. 2 ml of TL-201 chloride (74 MBp) is injected to locate the leakage in the system with planar images with a gamma camera (Elscint SP 6), 30 min, 2, 3, and 24 h after injection. RESULTS: The original ASGB was provided with an injection reservoir which, in our series, was found to be leaking in four cases (3%). CONCLUSIONS: Our technique for adjustment and leak detection appears to be simple and effective. Band-related problems such as reservoir leak should disappear with improvement of the material.

Journal Article↗
PubMed1996

Human kidney 11 beta-hydroxysteroid dehydrogenase: regulation by adrenocorticotropin?

In ectopic adrenocorticotropin (ACTH) syndrome (EAS) with higher ACTH levels than in pituitary Cushing's syndrome and during ACTH infusion, the ratio of cortisol to cortisone in plasma and urine is increased, suggesting inhibition of renal 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) by ACTH or by ACTH-dependent steroids. Measuring the conversion of cortisol to cortisone by human kidney slices under different conditions, we tested the possibility of 11 beta-HSD regulation by ACTH and corticosteroids. Slices prepared from unaffected parts of kidneys removed because of renal cell carcinoma were incubated with unlabeled or labeled cortisol, and cortisol and cortisone were quantitated after HPLC separation by UV or radioactive detection. The 11 beta HSD activity was not influenced by incubation with increasing concentrations (10(-12)-10(-9) mol/l) of ACTH (1-24 or 1-39) for 1 h. Among 12 ACTH-dependent steroids tested (10(-9)-10(-6) mol/l), only corticosterone (IC50 = 2 x 10(-7) mol/l), 18-OH-corticosterone and 11 beta-OH-androstenedione showed a significant dose-dependent inhibition of 11 beta-HSD activity. The percentage conversion rate of cortisol to cortisone was concentration dependent over the whole range of cortisol concentrations tested (10(-8) - 10(-5) mol/l. A direct inhibitory effect of ACTH on 11 beta-HSD is, therefore, unlikely. The only steroids inhibiting the conversion of cortisol to cortisone are natural substrates for 11 beta-HSD. Kinetic studies show a saturation of the enzyme at high cortisol concentrations. Thus, the reduced percentage renal cortisol inactivation in EAS seems to be due mainly to overload of the enzyme with endogenous substrates (cortisol, corticosterone and others) rather than to direct inhibition of 11 beta-HSD by ACTH or ACTH-dependent steroids, not being substrates of 11 beta-HSD.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1996

[Traveling on the data highway--online information for urologists].

Global exchange of information is one of the major sources of scientific progress in medicine. Electronic media have recently supplemented the standard methods of scientific communication such as congresses, books and journals. Currently, 30 million computers are part of the world-wide, exponentially growing network, the ""information superhighway''. Numerous resources offered by the network are becoming increasingly useful in clinical medicine. In Germany, three major networks are currently available: T-Online/Datex-J, Compuserve and Internet. The majority of information relevant to urologists can be found in the Internet. This information includes medical journals that can either partly or completely be read online, online library catalogs, scientific images (pathology and radiology), and databases on urologic oncology and basic research in urology. Even outside academic institutions access to the "information superhighway" is easily available. Currently, the "information superhighway" constitutes a new source of database-type information; in the near future, medical education, clinical consultation and worldwide cooperation in clinical studies will be new fields of scientific communication employing worldwide computer networks.

Forecasting↗
PubMed1996

[Laparoscopic operations in urologic clinics--results of a survey].

This paper summarizes the results of a questionnaire initiated in August 1995 by the Arbeitskreis "Minimal invasive Urologie" of the Deutsche Gesellschaft für Urologie. We received 235 answers from a total of 380 departments, which were queried by fax. Laparoscopic surgery is currently performed in 36% of all answering departments and in 75% of all university divisions. However, only 5% of the departments do more than 30 procedures per year. The most frequent indications are cryptorchisdim in 24%, pelvic lymph node dissection in 20%, lymphoceles in 16%, renal cyst resection in 15%, varicocelectomy in 14%, and laparoscopic nephrectomy in 11% (30% of all laparoscopically active units). Since laparoscopy in urology does not have an indication for a high number of patients (and departments), knowledge about how to use this minimally invasive technique will be further concentrated in already existing centers, as this guarantees sufficient frequency of its use and expertise.

Cross-Sectional Studies↗
PubMed1996

Constitutive expression of fibroblast growth factor-4 does not alter the growth or the differentiation of embryonal carcinoma cells.

Previous studies have demonstrated that embryonal carcinoma (EC) cells express both fibroblast growth factor-4 (FGF-4) and FGF receptors. It has also been established that differentiation of EC cells represses the expression of the FGF-4 gene. Currently, the role of FGF-4 in the growth and differentiation of EC cells is unclear. In this study, we examined whether the differentiation of EC cells requires the repression of FGF-4 expression. To address this and related questions, F9 EC cells were transfected with an expression vector that uses the human beta-actin promoter to drive the constitutive expression of recombinant FGF-4. Unlike their untransfected counterparts, F9 EC cells transfected with this plasmid continue to produce recombinant FGF-4 after they differentiate. However, constitutive expression of this growth factor does not block morphological differentiation of the cells, nor does it alter the expression of six genes regulated by the differentiation of EC cells. Constitutive expression of recombinant FGF-4 also did not noticeably alter the growth of the transfected F9 EC cells before or after differentiation. Furthermore, unlike immortalized fibroblasts, which are known to grow in soft agar after transfection with FGF-4 expression plasmids, continued expression of recombinant FGF-4 activity did not enhance the ability of the EC-derived differentiated cells to form colonies in soft agar. These findings argue that continuous expression of recombinant FGF-4 activity does not block the differentiation of EC cells and that repression of the FGF-4 gene after EC cells differentiate does not appear, on its own, to be responsible for the loss of tumorigenicity that accompanies the differentiation of EC cells.

Actins↗
PubMed1996

Proliferation kinetics of chorionic villi in chromosomally normal and abnormal spontaneous abortions analyzed by premature chromosome condensation and northern blot.

The activity of cell proliferation in human chorionic villi (CV) obtained from early spontaneous abortions (SAB) and from elective abortions (EAB) was determined by means of premature chromosome condensation (PCC), and by Northern blot analysis of expression of proliferation antigens Ki67 and PCNA. The rate of chromosome aberrations among the SABs was 57%, while the EABs, taken as controls, were shown to be chromosomally normal. PCCs were induced by fusion of the chorionic interphase cells with mitotic Chinese hamster ovary (CHO) cells. To analyze the proliferation stages of the chorionic G1-interphases, the potential proliferation index (PPI) was ascertained. The PPI values found in SABs ranged from 36% to 97% as described for intensely proliferating tissues. They did not differ from the values found in the controls (34-90%), indicating maintenance of proliferation activity of CV cells even after death of the embryo in missed abortions. No significant PPI differences were observed between the abortion groups with different cytogenetic results. The expression of proliferation associated antigens Ki67 and PCNA showed no significant differences between mean values of the total of SABs and of the controls. However, the comparison of mean values of chromosomally abnormal with chromosomally normal SABs revealed a significantly reduced Ki67 activity in the SABs with chromosome aberrations. A similar results was obtained when comparing mean values of Ki67 and PCNA expression from trisomic SABs with those of the controls. By further subdivision of chromosome aberrations a decrease for the expression of both antigens in chorionic villi from early lethal trisomies, and a significantly increased Ki67- and PCNA-expression in triploidies became evident.

Abortion, Induced↗
PubMed1996

HIV risk behaviors among Dominican brothel and street prostitutes in New York City.

Latina women are overrepresented among AIDS cases in the United States. To assist in developing appropriate prevention and intervention programs, information regarding HIV risk behaviors is needed on the many diverse Latina subgroups. This study examined sociodemographic characteristics and HIV risk behaviors of Dominican female prostitutes, comparing those who worked primarily in brothels with those who were street workers. A total of 77 Dominican prostitutes (54 brothel; 23 street) were recruited in New York City to participate in a structured interview and were offered HIV testing. Ethnographic interviews were conducted with a subscale. Results indicated that there were many significant differences in demographics and risk behaviors between the two groups, and those working in brothels engaged in lower levels of risk behaviors. In addition, those working in brothels had closer ties to the Dominican and Spanish cultures. Implications for AIDS prevention efforts are discussed.

AIDS Serodiagnosis↗