The effect of estrogens and dietary calcium deficiency on the extracellular matrix of articular cartilage in G?ttingen miniature pigs.

Clinical observations have suggested that estrogens are involved in the pathogenesis of postmenopausal osteoarthritis (OA). However, positive and negative associations between the incidence of OA and serum estrogen concentrations have been reported. In contrast to this, osteoporosis is regarded as a disease with a strong estrogen-dependent component. Moreover, there is an interaction between estrogen and calcium deficiency: calcium supplementation potentiates the effect of estrogen therapy. The present study was designed to investigate how estrogen deficiency affects the articular cartilage depending on calcium supply. The distribution of different types of glycosaminoglycans and collagens can be used as an indicator for extracellular matrix changes induced by estrogen deficiency. Different levels of dietary calcium were therefore fed to intact and ovariectomized G?ttingen miniature pigs for one year before articular cartilage was harvested. The histochemical staining for heavy sulfated glycosaminoglycans in the extracellular matrix of ovariectomized miniature pigs, especially of those fed with a low calcium diet, was stronger in comparison to intact animals. In intact animals type II-collagen was immunodetected in all zones of unmineralized and mineralized articular cartilage, while immunostaining for this protein was negative to weak in the deep radiated fiber zone of ovariectomized minipigs. These results suggest that the synthesis of heavy sulfated glycosaminoglycans and immunohistochemically detectable type II-collagen is possibly influenced by estrogen deficiency. In conclusion, under estrogen deficiency, the extracellular matrix of articular cartilage underwent similar changes to those observed in physiologically aging cartilage where keratan sulfate is increased as a heavy sulfated glycosaminoglycan.     

An analytical solution for the SSFP signal in MRI.

Among previous analyses of the steady-state free-precession (SSFP) signal in rapid MRI, one treatment resulted in equations that require the evaluation of infinite binomial series. Here, an analytical solution is derived by a transformation into the power series expansion of the derivative of the inverse sine function, which is essentially a root. The treatment is extended to include higher-order signals. The results demonstrate the identity of the vastly different equations for the SSFP signals reported so far. Applications consist of the derivation of closed expressions for the signal in echo-shifted MRI and a corresponding analysis of TrueFISP sequences.     

Pränatale Diagnostik von Hämoglobinopathien im ersten Trimenon

Ohne Zusammenfassung     

Management of sacral and perineal defects following abdominoperineal resection and radiation with transpelvic muscle flaps

PURPOSES: In this study we present our experience with treating persistent sacral and perineal defects secondary to radiation and abdominoperineal resection with or without sacrectomy. METHODS: Fifteen consecutive patients were treated with an inferiorly based transpelvic rectus abdominis muscle or musculocutaneous flap. RESULTS: Fourteen of the 15 patients achieved healing, and 7 patients had no complications. The remaining eight patients required one or more operative debridements and/or prolonged wound care to accomplish a healed wound. Our technique for the dissection and insetting of the transpelvic muscle flap is presented. CONCLUSION: The difficult postirradiated perineal and sacral wounds can be healed with persistent surgical attention to adequate debridement, control of infections, and a well-vascularized muscle flap. The most satisfying aspects for patients are the discontinuance of foul-smelling discharge, discontinuation of multiple, daily dressing changes, and reduction in the degree of chronic pain.Read at the meeting of the Midwestern Association of Plastic Surgeons, Bismarck, North Dakota, June 15 to 18, 1992.     

Novel pluripotential neural progenitor lines exhibiting rapid controlled differentiation to neurotransmitter receptor‐expressing neurons and glia

The immortalization of progenitor cells from embryonic murine hippocampus using oncogene‐carrying retroviral vectors is described. Use of a vector encoding the oncogene v‐myc results in lines of nestin‐positive progenitor cells. Limited differentiation ensues if the cells are cultured in the presence of dibutyryl cyclic adenosine monophosphate. In contrast, use of a vector in which the extracellular portion of the epidermal growth factor (EGF) receptor is fused to the neu tyrosine kinase generates lines of pluripotential nestin‐positive progenitor cells, which differentiate upon withdrawal of EGF into neurons and glia. Differentiated neurons expressing action potentials and neurotransmitter receptors make up a high proportion of the cells. These cell lines are useful tools to investigate the characteristics of differentiating neurons and glia, as well as to screen neuroactive drugs. This work has been reported in preliminary form as an abstract (1996 Society for Neuroscience Abstract, #606.20, p. 1537).     

Dentists' opinions of their dental education; results of a survey of dentists who studied in Amsterdam between the years 1982-1990

Four hundred and fifty dental graduates from the Free University (VU), the University of Amsterdam (UvA) or the Academic Center for Dentistry Amsterdam (ACTA) between 1982 and 1990 were asked by questionnaire to give their opinion about the undergraduate dental training they received. Most respondents felt that their undergraduate education prepared them reasonably well for general practice. Yet imperfections in the education were noticed. These imperfections show resemblance to conclusions from similar surveys in other countries.     

C-13-NMR-spektroskopische untersuchungen an polymerhomologen reihen von α,1→6- und α,1→4-glucanen

The ¹³C-NMR spectra of malto- and isomalto-oligosaccharides, amylose and dextrane were analysed. It was observed that in both series of oligosaccharides and polysaccharides the resonances of the central glucose units are independent of the chain length with the exception of the C-atoms 1 and 4 of amylose which show deviations of 0,4 and 0,5 ppm. These small effects can possibly be explained by a definite polysaccharide chain conformation in solution.     

Different ocular abnormalities in individuals of a three-generation family caused by a new nonsense mutation in the PST domain of the PAX6 gene. Mutations in brief no. 189. Online

PAX6 is a candidate gene for familial aniridia. We have carried out a mutational analysis of the PAX6 gene in a three-generation family from Germany, containing 5 individuals affected with ocular abnormalities. In all affected individuals, a heterozygous mutation was detected in the PAX6 gene, exchanging tyrosine 369 by a stop codon. The mutation is located in the 3' moiety of the PST domain, at the C terminus of the PAX6 protein. In the affected family members, the same heterozygous mutation leads to distinct phenotypes of varying severity. Most notably, no aniridia was observed in one of the family members carrying the mutation, although other ocular abnormalities (underdeveloped iris and cataracts) were present. We discuss the possibility that small C terminal truncations of the PAX6 protein might lead to less severe or more divergent phenotypes than trancations at internal positions.     

Blinded, Externally Controlled Multicenter Evaluation of Light Microscopy and PCR for Detection of Microsporidia in Stool Specimens

The quality parameters for the detection of microsporidia in identical sets of 50 stool samples were determined for six laboratories where technicians used light microscopy and for six laboratories where technicians used PCR. The average overall sensitivities were 67% (89% for patient samples only) for the PCR laboratories and 54% (80% for patient samples only) for the light microscopy laboratories. Specificities were 98 and 95%, respectively. Differences in results were most apparent between the individual laboratories rather than between the two major methods used.     

20q13.2 Amplification in intraductal hyperplasia adjacent to in situ and invasive ductal carcinoma of the breast

The 20q13 region harboring recently described putative oncogenes is frequently amplified in invasive ductal carcinoma (IDC). The aim of this study was to examine the 20q13 copy number in intraduct hyperplasia (IH), atypical duct hyperplasia (ADH), and ductal carcinoma in situ (DCIS) adjacent to IDC. In 5 patients, comparative genomic hybridization (CGH) after laser microdissection revealed 20q13 amplification in four of five cases of IH, in all of three cases of IH with atypia, all five of DCIS, and all five of IDC. Fluorescence in situ hybridization (FISH) confirmed the amplification at 20q13.2 in IH in the two specimens analyzed. The amplification rate, however, was higher in DCIS and IDC. In phenotypically normal ductal epithelium normal values were found for 20q13 copy number by FISH (n=2) and CGH (n=5). Although the number of cases presented here is small, our results suggest that mutations in the 20q13.2 region in IH may be associated with accelerated proliferation and hyperplasia of the ductal epithelium. Progression to DCIS and ICD is accompanied by a further increase in the 20q13.2 copy number. Received: 17 March 1999 / Accepted: 22 June 1999