Biomedical subjects
Publications and source records attributed to D Wagner.
The best quality control in the examination of the alloimmunization of blood preparations is not the counting of leukocytes but the direct determination of the antigenicity by means of MAIPA. The results show a number of preparations containing about 50 p.c. of HLA antigenicity after filtration.
Stable isotope labeling in therapeutic and subtherapeutic quantities of drug (15N2(13)C-phenobarbital) can be quantitated in biological matrices (urine) and high performance liquid chromatography (HPLC) peaks from urine using continuous-flow isotope-ratio mass spectrometry (CF-IRMS). Standard curves for 15N2(13)C-phenobarbital were reproducible and linear (R2 > 0.985) over the ranges of 3-100 micrograms/ml for whole urine (15N2 or 13C labeling) and 0.1-8.0 micrograms/mL for HPLC peaks derived from urine (15N2 labeling). The lower limit of quantitation values for urine drug concentration was 0.46-2.62 micrograms/mL in whole urine and 0.10-0.70 micrograms/mL in HPLC peaks. Validation samples quantitated with these standard curves yielded close to expected values. These data suggest stable isotope labeling and CF-IRMS may be used as an alternative to 14C labeling and radioactivity counting methods in mass balance/metabolite identification and other biomedical studies.
Explore the source record for details and available documents.
BACKGROUND: Peptide YY (PYY) given intravenously was shown to inhibit pancreatic exocrine secretion both in the dog and the rat. However, a possible physiological role of PYY on the pancreatic secretion has not been clarified. The present study was undertaken to investigate its physiological role on the exocrine pancreas. METHODS: In conscious rats, plasma PYY was determined in response to oral ingestion of a 6-mL meal and intravenous infusion of PYY; small intestinal transit time was measured by phenol red as a nonabsorbable marker, and pancreatic secretory studies were performed in rats with pancreatic fistulas and jugular vein catheters. RESULTS: Oral ingestion of the meal (containing phenol red, 1.6 mg/100 mL) significantly increased plasma PYY within 30 minutes. During this period, most (97%) of the phenol red was detected in the proximal two-thirds of the small intestine. Intravenous infusion of PYY in 25, 50, and 100 pmol.kg-1 x h-1 produced a dose-dependent increase in plasma PYY. The dose of PYY that simulated the peak postprandial level was 50 pmol.kg-1 x h-1, and this dose of PYY significantly inhibited the pancreatic secretion stimulated by physiological doses of secretin and cholecystokinin-8 (CCK-8). After the meal, pancreatic secretion of bicarbonate and protein significantly increased in rats pretreated with normal rabbit serum, whereas this increase was significantly augmented in rats pretreated with an anti-PYY serum because the postprandial increase in plasma PYY was abolished. CONCLUSIONS: PYY plays a regulatory role in the postprandial pancreatic exocrine secretion in rats.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
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.
Some 86 heart transplant recipients under immunosuppressive therapy were vaccinated against hepatitis B using the vaccine Gen H-B-Vax-D, but 95.3% failed to develop protective levels of HBs-specific antibody (more than 10 U/l) after the third vaccination.
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%.
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.
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.
Explore the source record for details and available documents.
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.
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.
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.
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.
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.