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Biomedical subjects

D Wagner

Publications and source records attributed to D Wagner.

At least 19 recordsLinked to original sources
PubMed1992

COP1, an Arabidopsis regulatory gene, encodes a protein with both a zinc-binding motif and a G beta homologous domain.

Plant seedling development is capable of following 1 of 2 distinct morphogenic pathways: skotomorphogenesis in darkness and photomorphogenesis in light. Dark-grown Arabidopsis seedlings with recessive mutations at the constitutively photomorphogenic (COP1) locus indicate that the wild-type COP1 protein represses photomorphogenesis in darkness and that light reverses this repressive activity. Using a T-DNA-tagged mutant, we have cloned the COP1 locus. The amino-terminal half of the encoded protein contains a conserved zinc-binding motif, whereas the carboxyl-terminal half contains a domain homologous to the WD-40 repeat motif of G beta proteins. The presence of both a putative DNA-binding motif and a G protein-related domain in a single polypeptide suggests that COP1 may be the first of a new class of regulatory molecules. This novel structure could endow COP1 with the capacity to function as a negative transcriptional regulator capable of direct interaction with components of the G protein signaling pathway.

Amino Acid Sequence↗
PubMed1992

Human papillomavirus DNA in women without and with cytological abnormalities: results of a 5-year follow-up study.

To determine the prevalence of HPV 6, 11, 16, and 18 in a population without cytological or histological abnormalities, the cervical smears of women attending three clinics in Germany were screened over the past 5 years. The filter in situ hybridization method was used throughout. A total of 20,161 smears, taken from 11,667 women, were tested. When the results of only the first examination are considered, 8.8% (950/10,778) of women with normal cytology were positive for HPV DNA. If we divide the latter into age groups, 11% (852 HPV positive/7716) were below the age of 55 years and 3.2% (98 HPV positive/3062) were above this age. When the samples from patients who had undergone at least two examinations and remained cytologically negative during the 5-year period were examined (total, 2709 women), the HPV DNA positively increased to 34.7% (640/1862) for the sexually active age groups and to 9.0% (76/847) for those above 55 years of age. This study reveals that, although papillomaviral production is most pronounced in younger women, these infections are quite common in all age groups. During the period of investigation, 19 (0.65%) patients, who were diagnosed as cytologically negative at the first examination, progressed to carcinoma in situ or invasive carcinoma. Of these, 63.2% revealed a detectable HPV infection during the study period. The progression of HPV-positive women from normal cytology to CIN or cancer occurred at an annual frequency of 0.082%. With an infected lifespan of 45 years assumed, this results in a lifetime risk of 3.7%.

Adolescent↗
PubMed1991

Human papillomavirus type 16 DNA in ocular and cervical swabs of women with genital tract condylomata.

Human papillomavirus type 16 is associated with dysplasias and carcinomas of the conjunctiva and of the uterine cervix. To explore the relationship between cervical and ocular human papillomavirus infection, we examined DNA from bilateral limbal swabs and cervical swabs from 17 women (age range, 17 to 46 years; median, 31.7 years) with biopsy-proven human papillomavirus-related cervical dysplasia who had a normal ocular surface. Using polymerase chain reaction, we identified human papillomavirus 16 DNA in one or both eyes of 13 (76.5%) patients, six (46.2%) of whom had demonstrable human papillomavirus 16 DNA in cervical swabs as well. It thus appears that human papillomavirus 16 is present in the conjunctivae of some patients with human papillomavirus-related genital warts who have no ocular manifestations of infection. Although autoinoculation of conjunctiva may be the source of some ocular human papillomavirus, data suggest that other modes of transmission to the eye also exist. Additional study of the epidemiologic characteristics of ocular human papillomavirus, a widely prevalent virus known to be associated with dysplasias/atypias and cancer, is warranted.

Adolescent↗
PubMed1991

Highly resolving two-dimensional gels for protein sequencing.

Two-dimensional (2D) PAGE, using carrier ampholytes for the first-dimension separation, has provided a tool for the simultaneous analysis of cellular proteins. To extend the utility of 2D PAGE to the preparative level, we have investigated the use of immobilized pH gradients (IPG) for the first-dimension separation. The results we have obtained indicate that as much as 1 mg of cellular protein can be loaded onto a single IPG gel without loss of resolution. Mutant polypeptides previously detected in carrier ampholyte-based 2D gels were equally detectable in IPG-based 2D gels. With IPG gels several hundred cellular polypeptides can be isolated, from as few as 10 gels, in sufficient amount for sequencing with current sequencing technology. We therefore conclude that IPG greatly enhances the prospects for the large-scale sequencing of cellular proteins for the development of 2D gel-related protein data bases and for the identification of new polypeptide gene products, with the attendant implications for a genome sequencing effort.

Amino Acid Sequence↗
PubMed1991

Development of a new in vitro model for studying implantable polyurethane calcification.

The objective of this study was to reproduce mineralization of polymeric substrate in an extracirculatory environment which would facilitate investigation of the calcification mechanism in implantable biomaterials and methods of prevention. Calcification was examined on polyurethane films incubated in metastable solutions of calcium phosphate and the role of strain, serum and polymer porosity was examined. Validation of the model was evaluated by examining the calcification of both highly calcifiable biomaterial (bioprosthetic tissue) and a non-calcifiable biomaterial (charge-modified tissue and polyurethane containing anticalcification agent). It is concluded that the developed model is adequately sensitive to diagnose biomaterials' propensity to calcify and could serve as a pre-screening method to examine calcification mechanism and methods of prevention.

Biocompatible Materials↗
PubMed1991

HMB-45 immunohistochemical staining of conjunctival melanocytic lesions.

HMB-45 is a monoclonal antibody recently described as being highly specific for melanocytic proliferations of the skin and in metastases of melanotic lesions. To determine a possible role for HMB-45 in ophthalmic pathology, 45 conjunctival lesions, including 23 melanomas, were analyzed using immunohistochemical techniques with anti-S-100 and HMB-45 as primary antibodies. Nineteen (82.6%) of the melanomas exhibited HMB-45 positivity, and 19 (82.6%) contained S-100 protein, with concordance of all but two cases. Seven cases of primary acquired melanosis were studied; one (33%) of three with atypia was HMB-45 positive, as were two (50%) of four without atypia. Among nevi, 1 (9.1%) of 11 showed faint staining with HMB-45. Fifteen conjunctival epithelial dysplasias were negative with HMB-45. At present, HMB-45 appears to offer no great advantage over S-100 protein in the analysis of conjunctival melanomas. Its role in the distinction of benign from atypical or malignant junctional melanocytic proliferations remains unclear.

Antibodies, Monoclonal↗
PubMed1991

Sinusoidal fetal heart rate pattern during labor.

Of 1280 consecutive fetuses monitored internally with a scalp electrode for at least 10 minutes during labor, 54 (4.2%) demonstrated the sinusoidal heart rate (SHR) pattern. Seven of these demonstrated the SHR pattern for more than 90 minutes. In six of these seven cases, the SHR pattern occurred during oxytocin administration. The SHR group did not differ from the 1226 fetuses not demonstrating the SHR pattern (NSHR group) in Apgar scores, incidence of other fetal heart rate abnormalities, or passage of meconium. The scalp pH was obtained from three fetuses in the SHR group and was above 7.30 in each. Alphaprodine administration during labor was associated with development of the SHR pattern, whereas other narcotic administration was not. The significance of "atypical" SHR pattern with increased amplitude is discussed, along with the need to adhere to strict definition of the SHR pattern.

Apgar Score↗
PubMed1991

[Intestinal absorption of insulin with a new telemetric shuttle in dogs].

Telemetric shuttles for the in vivo investigation of the gastrointestinal tract have been available for sometime. We describe herein the use of a new shuttle model whose original features include: a) continuous, real time transmission of its location in the small bowel and accurate measurement of the gut length, b) controlled release of 1 ml of a given substance at any chosen site, allowing detailed investigation of intestinal absorption at different levels of the small bowel under physiological conditions. Small bowel length was measured in dogs using the shuttle and was later compared to the actual small gut length measured in the same animals at laparotomy. The telemetric measurements appeared to closely match the direct operative measurements. Insulin absorption from the canine small bowel was then investigated releasing different dosages of insulin together with the pancreatic enzyme inhibitors Soybean and Aprotinine and a surfactant (5-methoxysalicylate). By adjusting the dose of insulin released, the type of adjuvant substance delivered with it and the site of release in the small bowel, we have been able to precisely define the conditions of insulin absorption. Insulin as such is exclusively absorbed in the ileum when released in doses of 500 IU or higher and mixed with aprotinine. For absorption to take place the solution delivered by the shuttle needs to have the correct pH and natremic concentration.

Animals↗
PubMed1991

Reviving the action research model: combining case and cause with dislocated workers.

Action research, a model combining research with activist goals and microlevel and macrolevel social work practice, has received little recent attention in the social work literature. This article reports on an action research project conducted by a major labor union and a university department of social work to assist dislocated workers in New England. A partnership of union-trained peer counselors and social work faculty and students combined a research study with providing direct service to displaced workers, assisting in an organizing project, and developing a policy agenda to assist low-income workers. The author suggests that an action research model can be used by social workers in a wide variety of settings and under different practice auspices.

Humans↗
PubMed1990

DNA measurements and ploidy determination of different stages in the life cycle of Sarcocystis muris.

The DNA contents of different stages within the life cycle of Sarcocystis muris were measured cytophotometrically using DNA-specific Feulgen staining. Stages of gamogony were obtained by the transfer of isolated cyst merozoites into cat kidney-cell cultures. For calculation of absolute DNA contents, the amounts of DNA in the parasites were compared with those in chicken erythrocytes, which are known. The measurements revealed that all investigated stages of S. muris contained haploid DNA except the early zygotes, which were diploid. The further development of the zygotes started with a nuclear division, resulting in two daughter nuclei that again revealed haploid DNA values. The results confirm the existence of zygotic meiosis; thus, a haplo-homophasic life cycle is proposed for the Sarcosporidia.

Animals↗
PubMed1990

Characterization of Listeria monocytogenes isolates by Southern blot hybridization.

A synthetic deoxyribonucleotide probe for virulent Listeria monocytogenes, designated ADO7, was evaluated for its ability to identify restriction fragments of L. monocytogenes with nucleic acid sequences homologous with the beta-hemolysin gene by Southern blot hybridization of clinical and food isolates. The synthetic probe hybridized with three restriction fragments (approximately 1.1, 0.86, and 0.76 kb) of the serotype 1/2A isolates. Southern blot hybridization of the serogroup 4B isolates indicated that the nucleic acid sequences homologous with the beta-hemolysin gene probe were limited to a single restriction fragment of approximately 1 kb.

Animals↗
PubMed1990

Androgen dependence and tissue specificity of renin messenger RNA expression in mice.

Testosterone, a steroid hormone which increases blood pressure by hitherto unknown mechanisms, is known to induce renin synthesis in the submandibular gland (SMG) of mice. Since renin as well as all other components of the renin-angiotensin system are present in organs important for cardiovascular control, e.g. the kidney, heart, adrenal gland and brain, it is of interest to study the effect of testosterone on renin gene expression in these organs. Renin messenger (m) RNA concentrations were measured by a solution hybridization assay using a 32P-labeled mouse SMG renin complementary (c) RNA as a radioactive probe (detection limit: 1 pg renin mRNA). Measurements were performed after 2 h and after 2, 7, 14 and 21 days of dihydrotestosterone (DHT) treatment in female NMRI mice. Renin mRNA concentration (values are expressed as pg renin mRNA/ micrograms total RNA) in the SMG was significantly increased after 7 days (108 +/- 22 in controls versus 630 +/- 101 in DHT-treated mice), after 14 days (83 +/- 15 in controls versus 743 +/- 83 in DHT-treated mice) and after 21 days (107 +/- 30 in controls versus 579 +/- 76 in DHT-treated mice), but did not reach levels found in untreated male NMRI mice (1021 +/- 84). In the kidney, a decrease was observed within 21 days, from 43 +/- 4 and 40 +/- 4 to 29 +/- 2 and 22 +/- 1.7 pg/micrograms in controls and DHT-treated groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
PubMed1990

Energy expenditure and subsequent nutrient intakes in overfed young men.

We investigated the mechanisms of body weight regulation in young men of normal body weight leading unrestricted lives. Changes in total and resting energy expenditure, body composition, and subsequent voluntary nutrient intakes in response to overeating by 4,230 +/- 115 (SE) kJ/day (1,011 +/- 27 kcal/day) for 21 days were measured in seven subjects consuming a typical diet. On average, 85-90% of the excess energy intake was deposited (with 87% of this amount in fat and 13% in protein on average). There was no detectable difference between individuals in susceptibility to energy deposition. The resting metabolic rate, averaged for fasting and fed states, increased during overfeeding (mean +/- SE, 628 +/- 197 kJ/day, P less than 0.01), but at least some of this amount was obligatory expenditure associated with nutrient assimilation. No significant increase in energy expenditure for physical activity or thermoregulation resulted from overfeeding. Thus energy expenditure did not substantially adapt to increased energy intake. However, significant decreases in voluntary energy intake (1,991 +/- 824 kJ/day, P less than 0.05) and fat intake (48 +/- 11 g/day, P less than 0.01) followed overeating, indicating that adaptive changes in nutrient intakes can contribute significantly to body weight regulation after overeating.

Adult↗
PubMed1989

The calcium requirement for stability and enzymatic activity of two isoforms of barley aleurone alpha-amylase.

alpha-Amylases (EC 3.2.1.1) secreted by the aleurone layer of barley grains are Ca2+-containing metalloenzymes. We studied the effect of Ca2+ on the activity and structure of the two major groups of aleurone alpha-amylase by incubating affinity purified enzyme in solutions containing Ca2+ from pCa 4 to 7. Both groups of isoforms required one atom of Ca2+/molecule of enzyme as determined by isotope exchange, but the two groups differed by more than 10-fold in their affinity for Ca2+. Both groups of alpha-amylase were irreversibly inactivated by incubation in low Ca2+ (pCa 7). This inactivation was not due to changes in primary structure, as measured by molecular weight, but appeared to be the result of changes in secondary and tertiary structure as indicated by circular dichroism spectra, serology, lability in the presence of protease, and fluorescence spectra. Analysis of the predicted secondary structure of barley aleurone alpha-amylase indicates that the Ca2+-binding region of barley amylases is structurally similar to that of mammalian alpha-amylases. Our data indicate that micromolar levels of Ca2+ are required to stabilize the structure of barley alpha-amylases in the endoplasmic reticulum of the aleurone layer where these enzymes are synthesized.

Calcimycin↗