Extreme virilization in patients with congenital adrenal hyperplasia fails to induce descent of the ovary

The commonly held hypothesis that androgens cause testicular descent in the male [9] predicts that excess endogeous androgens in the female fetus might cause descent of the ovary. To re-evaluate this prediction from a clinical perspective, a retrospective review was made of genotypic females with congenital adrenal hyperplasia and severe virilization. Patients with maximal virilization were included, since this is the group with the earlies and highest production of adrenal androgens during fetal development. Records were reviewed of five children in whom the external genitalia were completely or almost completely masculinized, who had been regarded as males with undescended testes at birth. The position of the ovaries was determined where possible from operative or pathological reports. In four patients the ovaries had been identified at operation, and were found to be in their normal position. In none were the ovaries in or adjacent to the inguinal canal. In the most recent patient, who presented in 1979, laparotomy was not performed because of the belief that the female internal genitalia were normal. In addition, review of the literature revealed two other similar female children with maximal virilization but documented normal ovarian position. The significance of these well-known findings has been ignored in recent studies of testicular descent. Failure of endogenous androgens to affect ovarian position supports the view that initiation of gonadal descent is independent of androgens. Since Müllerian inhibiting substance is the other recognizable hormone in the fetal testis apart from testosterone, it is suggested that it may be responsible for initiating gonadal descent.     

Transplantation von Ammionmembran mit oder ohne allogener Limbustransplantation zur Rekonstruktion der kornealen Oberfläche bei Limbusinsuffizienz

Zusammenfassung Fragestellung: Stellenwert der Transplantation von Amnionmembran (AMT) zur Rekonstruktion des perilimbalen Stromas bei Patienten mit Limbusinsuffizienz (LI). Desweiteren wurde die Erfolgsrate der AMT mit oder ohne allogener Limbustransplantation (aLT) bei LI analysiert. Patienten und Methode: 47 Augen von 42 Patienten mit einer zytologisch nachgewiesenen, ?tiologisch unterschiedlichen LI wurden prospektiv untersucht. Die Patienten wurden in Abh?ngigkeit des Auspr?gungsgrades der LI in drei Gruppen eingeteilt. In Gruppe A (fokale/partielle LI, 18 Augen) wurde nur eine AMT, in Gruppe B (moderate LI, 13 Augen) eine AMT und aLT und in Gruppe C (ausgepr?gte, komplette LI, 16 Augen) eine AMT, aLT und perforierende Keratoplastik (pKP) durchgeführt. Mit Ausnahme der Gruppe A erfolgte bei allen Patienten eine systemische Behandlung mit Cyclosporin A. Ergebnisse: Alle bis auf 2 Augen, die als Grunderkrankung eine atopische Keratitis hatten, zeigten eine rasche Epithelialisierung (2–4 Wochen), eine reduzierte Entzündung, Vaskularisation und Narbenbildung im Bereich der von Amnionmembran gedeckten Oberfl?che, die sich glatt und benetzt darstellte. In einem durchschnittlichen Nachbeobachtungszeitraum von 23 Monaten erzielten 38 Augen (82.6%) eine verbesserte Sehsch?rfe. In 15 Augen wurde eine Zunahme um 6 oder mehr Sehsch?rfenstufen (SS), in 10 Augen um 4–5 SS und in 13 Augen um 1–3 SS beobachtet. In Gruppe A zeigten 16 von 18 Augen (88.9%), in Gruppe B 10 von 13 (77%) und in Gruppe C 12 von 16 Augen (75%) eine Visuszunahme. Eine Absto?ung des Hornhauttransplantates trat in 12 von 16 Augen (75%) in Gruppe C auf. Eine frühe, reversible Absto?ung des Limbustransplantates wurde in 3 von 29 (10.3%) Augen und eine rezidivierende Limbusinsuffizienz in 8 von 29 (27.6%) Augen der Gruppen B und C beobachtet. Schlu?folgerung: Bei einer fokalen LI mit oberfl?chlicher Hornhautbeteiligung ist die AMT ausreichend und somit der aLT überlegen, da hier die systemische Applikation von Cyclosporin A entf?llt. Bei einer ausgepr?gten, kompletten LI ist eine zus?tzliche aLT erforderlich und in diesen F?llen begünstigt die AMT durch Reduktion der Entzündung und Vaskularisation im perilimbalen Stroma die Prognose der LT.      

The role of NGF signaling in human limbal epithelium expanded by amniotic membrane culture

PURPOSE: Amniotic membrane (AM) transplantation facilitates rapid epithelialization in severe neurotrophic corneal ulcers. To elucidate its action mechanism, we investigated the expression of ligands and receptors of the neurotrophin family by human limbal epithelial (HLE) cells expanded on AM cultures. METHODS: Expression of nerve growth factor (NGF); neurotrophins (NT)3 and NT4; brain-derived neurotrophic factor (BDNF); tyrosine kinase-transducing receptors TrkA, TrkB, and TrkC; and a pan-NT low-affinity receptor (p75(NTR)) was examined by immunostaining in the normal human corneolimbus, HLE grown on intact epithelially denuded AM, and stratified HLE, after subcutaneous implantation in NIH-bg-nu-xid BR mice. NGF protein level was assayed by an ELISA in extracts of intact and epithelially denuded AM. K252a, a specific inhibitor of TrkA autophosphorylation, was added to test whether it would inhibit HLE expansion on AM culture. RESULTS: Strong positive TrkA staining was confined to the basal epithelial cell layer of normal corneal and limbal epithelia, with the highest intensity noted in the limbus. TrkA staining was also strongly positive in the basal layer of HLE cells cultured on intact and epithelially denuded AM and in basal and some suprabasal layers of stratified HLE transplanted in nude mice. Positive staining of p75(NTR) was noted in the full-thickness of the corneal epithelium but was limited to the superficial layers of the limbus and in HLE cells cultured on intact and epithelially denuded AM, but was weak in HLE transplanted to nude mice. Weak staining of NT3 and TrkC was noted in the suprabasal layers of corneal and limbal epithelia but was negative in the stratified HLE in nude mice. Negative staining of NGF, NT4, BDNF, and TrkB was noted in all specimens tested. The NGF protein level was readily measured as 35.6 +/- 9.1 and 41 +/- 12.5 pg/mg protein in the homogenate of the intact and epithelially denuded AM, respectively (P = 0.0256). K252a significantly inhibited the HLE outgrowth on intact AM culture (P = 0.024). CONCLUSIONS: The strong expression of TrkA but not p75(NTR) in the limbal basal epithelial cells in vivo suggests that NGF signaling favors limbal epithelial stem cell survival. Such a phenotype is preserved in HLE cells on AM. Blocking NGF signaling significantly retarded HLE expansion on AM, supporting the notion that NGF is important in expansion of limbal epithelial progenitor cells. Furthermore, a high and therapeutic level of NGF was present in AM. Collectively, these findings indicate that denervated neurotrophic ulcers are associated with poor epithelial stem cell function at the limbus. Future studies are needed to determine whether AM transplantation to heal such ulcers may include the promotion of nerve regeneration and survival of epithelial progenitor cells.     

Expansion of conjunctival epithelial progenitor cells on amniotic membrane

Amniotic membrane (AM) reconstructed human conjunctival surfaces recover a goblet cell density higher than normal. Cultured rabbit conjunctival epithelial cells (RCE) on AM preferentially exhibit non-goblet epithelial differentiation. It was thus wondered if conjunctival progenitor cells that might have been preserved during ex vivo expansion on AM can still differentiate into conjunctival non-goblet epithelial and goblet cells under the influence of mesenchymal cells. Fourteen day old AM cultures of RCE were subcutaneously implanted in Balb/c athymic mice for 11 days and processed for PAS staining and immunostaining with monoclonal antibodies to conjunctival goblet cell mucin (MUC5AC, AM3), glycocalyx (AMEM2), cornea specific cytokeratins K3 (AE5) and K12 (AK2) and basal cell specific cytokeratin K14. Cell cycle kinetics were measured by BrdU labelling for 1 or 7 days. The 7 day labelled RCE were chased for 14 days in the same primary culture. After subcutaneous implantation, conjunctival non-goblet epithelial cells increased stratification and formed occasional cysts. The resultant epithelial phenotype was conjunctival with many PAS-positive, MUC5AC-positive, and AM3-positive goblet cells, AMEM2-positive suprabasal and superficial cells, and K14-positive basal cells, but was not corneal (negative to AE5 and AK2 staining). Twenty four hr BrdU labelling showed a labelling index of 42.5%. A higher labelling index or 69% was noted after continuous BrdU labelling for 7 days. A large number of label retaining basal cells with a labelling index of 84% were noted following 14 days of chase. Conjunctival epithelial progenitor cells for goblet and non-goblet cell differentiation are preserved by AM in vitro as evidenced by being able to differentiate into goblet cells in a permissive stromal environment, and being slow-cycling, and label retaining. This information is useful for future ex vivo expansion of conjunctival epithelial stem cells for conjunctival surface reconstruction.     

Phenotypic comparison of two Scottish families with mutations in different genes causing autosomal dominant nocturnal frontal lobe epilepsy

PURPOSE: Mutations in genes coding for the alpha 4 and beta 2 subunits of the neuronal nicotinic acetylcholine receptor receptor (CHRN) are known to cause autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE). Here we examined the phenotypes in two families, from the same ethnic and geographic backgrounds, with ADNFLE as a result of mutations in these two different subunits of CHRN. METHODS: All affected family members underwent a detailed clinical evaluation and review of available EEG, neuroimaging, and videotapes of seizures. The molecular study of family D is reported here; family S has a previously reported mutation in the beta 2 subunit of CHRN. RESULTS: A total of 16 individuals with ADNFLE were identified in the two families. In both families, seizure semiology, age at seizure onset, and the natural history of the seizure disorder was similar. Intrafamilial variation in terms of severity of epilepsy syndrome was present in both families. A significant number of individuals from each family had a history of psychological problems. The molecular study of family D revealed a Ser248Phe mutation in the alpha 4 subunit of CHRN. CONCLUSIONS: The epilepsy phenotype is not distinguishable in the two families who have ADNFLE as a result of mutations in genes coding for different CHRN subunits. This is likely to be due to the similar functional consequences of each mutation on the CHRN receptor.     

Major vault protein, a marker of drug resistance, is upregulated in refractory epilepsy

PURPOSE: The molecular basis of drug resistance in epilepsy is being explored. Two proteins associated with drug resistance in cancer, P-glycoprotein and multidrug resistance-associated protein 1, are upregulated in human epileptogenic pathologies. Other proteins associated with resistance in cancer include major vault protein (MVP) and breast cancer resistance protein (BCRP). We hypothesized that these proteins would also be upregulated in human epileptogenic pathologies. METHODS: Hippocampal sclerosis (HS), focal cortical dysplasia (FCD), and dysembryoplastic neuroepithelial tumor (DNT) were studied by using immunohistochemistry for MVP and BCRP. Nonepileptogenic control and histologically normal brain adjacent to epileptogenic tissue were used for comparison. RESULTS: MVP and BCRP were expressed ubiquitously in brain capillary endothelium. Ectopic upregulation of MVP was seen in hilar neurons in HS, dysplastic neurons in FCD, and lesional neurons in DNT. Only in HS cases were rare extralesional neurons immunoreactive. Glial upregulation was not seen. There was no qualitative upregulation of BCRP. CONCLUSIONS: These results show that more than one resistance protein may be upregulated in a given epileptogenic pathology and may contribute to drug resistance. Determination of the types, amounts, and distribution of such proteins will be necessary for rational treatment for drug resistance in epilepsy.     

Perpest model,a case-based reasoning approach to predict ecological risks of pesticides

The PERPEST model is a model that predicts the ecological risks of pesticides in freshwater ecosystems. This model simultaneously predicts the effects of a particular concentration of a pesticide on various (community) endpoints. In contrast to most effect models, PERPEST is based on empirical data extracted from the literature. This model is based on case-based reasoning, a technique that solves new problems (e.g., what is the effect of pesticide A?) by using past experience (e.g., published microcosm experiments). The database containing the past experience has been constructed by performing a review of freshwater model ecosystem studies. This review assessed the effects on various endpoints (e.g., community metabolism, phytoplankton, and macroinvertebrates) and classified them according to their magnitude and duration. The PERPEST model searches for analogous situations in the database, based on relevant (toxicity) characteristics of the compound. This allows the model to predict effects of pesticides for which no effects on a semifield scale have been published. The PERPEST model results in a prediction showing the probability of classes of effects (no, slight, or clear effects, plus an optional indication of recovery) on the various grouped endpoints. This paper discusses the scientific background of the model as well as its strengths, limitations, and possible applications.     

No evidence for association of ataxia-telangiectasia mutated gene T2119C and C3161G amino acid substitution variants with risk of breast cancer

Background  

There is evidence that certain mutations in the double-strand break repair pathway ataxia-telangiectasia mutated gene act in a dominant-negative manner to increase the risk of breast cancer. There are also some reports to suggest that the amino acid substitution variants T2119C Ser707Pro and C3161G Pro1054Arg may be associated with breast cancer risk. We investigate the breast cancer risk associated with these two nonconservative amino acid substitution variants using a large Australian population-based case–control study.