Control of hair follicle cell fate by underlying mesenchyme through a CSL–Wnt5a–FoxN1 regulatory axis

Epithelial–mesenchymal interactions are key to skin morphogenesis and homeostasis. We report that maintenance of the hair follicle keratinocyte cell fate is defective in mice with mesenchymal deletion of the CSL/RBP-Jκ gene, the effector of “canonical” Notch signaling. Hair follicle reconstitution assays demonstrate that this can be attributed to an intrinsic defect of dermal papilla cells. Similar consequences on hair follicle differentiation result from deletion of Wnt5a, a specific dermal papilla signature gene that we found to be under direct Notch/CSL control in these cells. Functional rescue experiments establish Wnt5a as an essential downstream mediator of Notch–CSL signaling, impinging on expression in the keratinocyte compartment of FoxN1, a gene with a key hair follicle regulatory function. Thus, Notch/CSL signaling plays a unique function in control of hair follicle differentiation by the underlying mesenchyme, with Wnt5a signaling and FoxN1 as mediators.     

Evaluation of SNPs in miR‐146a,miR196a2 and miR‐499 as low‐penetrance alleles in German and Italian familial breast cancer cases

Recently, the SNPs rs11614913 in hsa‐mir‐196a2 and rs3746444 in hsa‐mir‐499 were reported to be associated with increased breast cancer risk, and the SNP rs2910164 in hsa‐mir‐146a was shown to have an effect on age of breast cancer diagnosis. In order to further investigate the effect of these SNPs, we genotyped a total of 1894 breast cancer cases negative for disease‐causing mutations or unclassified variants in BRCA1 and BRCA2, and 2760 controls from Germany and Italy. We compared the genotype and allele frequencies of rs2910164, rs11614913 and rs3746444 in cases versus controls of the German and Italian series, and of the two series combined; we also investigated the effect of the three SNPs on age at breast cancer diagnosis. None of the performed analyses showed statistically significant results. In conclusion, our data suggested lack of association between SNPs rs2910164, rs11614913 and rs3746444 and breast cancer risk, or age at breast cancer onset. © 2009 Wiley‐Liss, Inc.     

Role of ADAMTSL4 mutations in FBN1 mutation‐negative ectopia lentis patients

Ectopia lentis (EL) is genetically heterogeneous with both autosomal‐dominant and ‐recessive forms. The dominant disorder can be caused by mutations in FBN1, at the milder end of the type‐1 fibrillinopathies spectrum. Recently in a consanguineous Jordanian family, recessive EL was mapped to locus 1q21 containing the ADAMTSL4 gene and a nonsense mutation was found in exon 11 (c.1785T>G, p.Y595X). In this study, 36 consecutive probands with EL who did not fulfill the Ghent criteria for MFS were screened for mutations in FBN1 and ADAMTSL4. Causative FBN1 mutations were identified in 23/36 (64%) of probands while homozygous or compound heterozygous ADAMTSL4 mutations were identified in 6/12 (50%) of the remaining probands. Where available, familial screening of these families confirmed the mutation co‐segregated with the EL phenotype. This study confirms that homozygous mutations in ADAMTSL4 are associated with autosomal‐recessive EL in British families. Furthermore; the first compound heterozygous mutation is described resulting in a PTC and a missense mutation in the PLAC (protease and lacunin) domain. The identification of a causative mutation in ADAMTSL4 may allow the exclusion of Marfan syndrome in these families and guide the clinical management, of particular relevance in young children affected by EL. © 2010 Wiley‐Liss, Inc.     

Reproducibility in the diagnosis of needle core biopsies of non‐palpable breast lesions: an international study using virtual slides published on the world‐wide web

Zito F A, Verderio P, Simone G, Angione V, Apicella P, Bianchi S, Conde A F, Hameed O, Ibarra J, Leong A, Pennelli N, Pezzica E, Vezzosi V, Ventrella V, Pizzamiglio S, Paradiso A & Ellis I
(2010) Histopathology 56, 720–726
Reproducibility in the diagnosis of needle core biopsies of non‐palpable breast lesions: an international study using virtual slides published on the world‐wide web Aims: To conduct an internet‐based study using virtual slides (VS) of sterotactic core biopsy specimens of non‐palpable breast lesions in order to evaluate interobserver reproducibility between pathologists. Methods and results: A total of 18 breast lesions, determined to be histologically complex by two pathologists, were selected. Digitized VSs were then created using QuickTime Virtual Reality technology (Apple, Cupertino, CA, USA) and posted on the world‐wide web. In all, 10 pathologists completed the evaluations of 18 VSs using the five diagnostic categories (B1–B5) from the European guidelines for quality assurance in breast cancer screening and diagnosis. Their results were compared with those of every other participating pathologist, and were then individually compared with the results of a highly experienced breast pathologist (referee). Of the 18 cases, 10 (56%) were classified by the referee as borderline (B3 and B4). Comparisons with reference values showed a less than satisfactory level of reproducibility (median κ_w = 0.60). As regards interobserver reproducibility, results showed that, in general, the level of agreement was not satisfactory (median κ_w = 0.53). Conclusions: Overall, the findings are comparable to those quality control studies using circulating slides when analysis is done on borderline cases.     

Congenital infection with human herpesvirus 6 variant B associated with neonatal seizures and poor neurological outcome

Human herpesvirus 6 (HHV 6) has neurotropic and neuroinvasive properties. The virus has been found in the cerebrospinal fluid of many children with aseptic meningoencephalitis. Intrauterine transmission has been documented by HHV 6 DNA detection in cord blood specimens of apparently healthy newborns and in fetuses following spontaneous abortions. A patient is described with early neonatal afebrile seizures resulting from a congenital HHV 6 variant B infection disclosed by repeated detection of viral genome by polymerase chain reaction (PCR) in cerebrospinal fluid in the first days of life. At follow-up, magnetic resonance imaging (MRI) studies disclosed hyperintensities in the periventricular white matter and basal ganglia, associated with cerebral atrophy. Further follow-up at 18 months revealed poor neurological outcome with mild neurodevelopmental retardation, strabismus and hypertonia of legs. This report provides evidence of neurological involvement after HHV 6 vertical transmission, and the association with neurological sequelae.     

Polyomavirus BK DNA quantification assay to evaluate viral load in renal transplant recipients.

BACKGROUND: Several studies have disclosed a correlation between polyomavirus BK (BKV) and interstitial nephritis in renal transplant recipients and its quantification in urine and serum is therefore required to assess the role of BKV infection in nephropathy. OBJECTIVE: This paper describes a urine and serum BKV-DNA quantification protocol devised to evaluate the viral load. STUDY DESIGN: Screening of samples containing > or =10(3)/ml viral genome copies by a semi-quantitative polymerase chain reaction (PCR) assay is followed by precise quantification of the samples containing a high number of viral genomes in a quantitative-competitive (QC)-PCR assay. Generation of the competitor construct relied on the different sizes of wild-type and competitor amplicons. RESULTS AND CONCLUSIONS: Screening by semi-quantitative PCR selects samples with a high number of viral genomes for use in the more labor-intensive and -expensive QC-PCR assay and thus provides a handy means for quantitative DNA analysis of large numbers of samples. The results obtained in BKV-DNA quantification in urine and serum samples from 51 renal transplant recipients (22 on treatment with tacrolimus (FK506) and 29 on cyclosporine A (Cy A)) are interesting: BKV-DNA findings (43.1%) in urine samples are in agreement with the BKV urinary shedding reported in literature (5-45%). With regard to immunosuppressive treatment, the percentage of activation of the infection (revealed by BKV-DNA detection in urine samples) in the two groups of therapy is similar (40.9% vs 44.8%). The observation that the viral load in urine is dissociated with that of serum suggests that both parameters should be investigated in evaluation of the pathogenetic role of BKV reactivation in renal transplant recipients. Moreover, our BKV-DNA quantification protocol could be used to monitor viral load in urine and serum samples from renal transplant recipients so as to detect those at risk of nephropathy and monitor their response to immunosuppression reduction therapy if it occurs.     

Acid–base balance at exercise in normoxia and in chronic hypoxia. Revisiting the "lactate paradox"

Transitions between rest and work, in either direction, and heavy exercise loads are characterized by changes of muscle pH depending on the buffer power and capacity of the tissues and on the metabolic processes involved. Among the latter, in chronological sequence: (1). aerobic glycolysis generates sizeable amounts of lactate and H(+) by way of the recently described, extremely fast (20-100 ms) "glycogen shunt" and of the excess of glycolytic pyruvate supply; (2). hydrolysis of phosphocreatine, tightly coupled with that of ATP in the Lohmann reaction, is known to consume protons, a process undergoing reversal during recovery; (3). anaerobic glycolysis sustaining ATP production in supramaximal exercise as well as in conditions of hypoxia and ischemia, is responsible for the accumulation of large amounts of lactic acid (up to 1 mol for the whole body). The handling of metabolic acids, i.e., acid-base regulation, occurs both in blood and in tissues, mainly in muscles which are the main producers and consumers of lactic acid. The role of both blood and muscle bicarbonate and non-bicarbonate buffers as well as that of lactate/H(+) cotransport mechanisms is analyzed in relation to acid-base homeostasis in the course of exercise. A section of the review deals with the analysis of the acid-base state of humans exposed to chronic hypoxia. Particular emphasis is put on anaerobic glycolysis. In this context, the so-called lactate paradox is revisited and interpreted on the basis of the most recent findings on exercise at altitude.     

Effects of 17-day spaceflight on electrically evoked torque and cross-sectional area of the human triceps surae

The effects of spaceflight on triceps surae muscle torque and cross-sectional area (CSA) were investigated on four astronauts using electrically evoked contractions to by-pass neural control. Muscle twitch characteristics, ankle joint angle–twitch torque relation, frequency–torque relation, tetanic torque and fatigability were assessed before, during and after a 17-day Space Shuttle flight (STS-78). Muscle plus bone cross-sectional area (CSAm+b) was evaluated before and after the flight. Whereas no changes in muscle function were observed during the flight, marked alterations were found during the recovery period. Peak twitch (PTw) and tetanic torques at 50 Hz (PT₅₀) continued to fall up to the 8th recovery day (R+8) on which losses in PTw and PT₅₀ were 24.4% (P<0.01) and 22.0% (P<0.01), respectively. The decline in PTw was not joint-angle-specific. Post-flight, especially on R+8, torque decreased at all stimulation frequencies (1, 20, 30 and 50 Hz); however the shape of the frequency–torque curve, normalised for PT₅₀, was not modified. Similarly, no changes in twitch kinetics were observed. Post- flight, an 8% (P<0.01) reduction in CSAm+b was found on R+2. Normalisation of PT₅₀ values for CSAm+b showed a progressive loss in specific torque (PT₅₀/CSAm+b), which was maximal on R+2 (19.5%, P<0.05). Also, fatigability during 2-min intermittent stimulation at 20 Hz increased throughout recovery, reaching a nadir of 16.4% (P<0.01) on R+15. In conclusion, 17 days of spaceflight resulted in significant changes in muscle function during the recovery phase, but not in microgravity. The disproportionate loss of torque compared with that of muscle size suggests the presence of muscle damage due to reloading in 1 g.     

Genotype-phenotype relationship in human ATP6i-dependent autosomal recessive osteopetrosis

Autosomal-recessive osteopetrosis is a severe genetic disease caused by osteoclast failure. Approximately 50% of the patients harbor mutations of the ATP6i gene, encoding for the osteoclast-specific a3 subunit of V-ATPase. We found inactivating ATP6i mutations in four patients, and three of these were novel. Patients shared macrocephaly, growth retardation and optic nerve alteration, osteosclerotic and endobone patterns, and high alkaline phosphatase and parathyroid hormone levels. Bone biopsies revealed primary spongiosa lined with active osteoblasts and high numbers of tartrate-resistant acid phosphatase (TRAP)-positive, a3 subunit-negative, morphologically unremarkable osteoclasts, some of which located in shallow Howship lacunae. Scarce hematopoietic cells and abundant fibrous tissue containing TRAP-positive putative osteoclast precursors were noted. In vitro osteoclasts were a3-negative, morphologically normal, with prominent clear zones and actin rings, and TRAP activity more elevated than in control patients. Podosomes, alphaVbeta3 receptor, c-Src, and PYK2 were unremarkable. Consistent with the finding in the bone biopsies, these cells excavated pits faintly stained with toluidine blue, indicating inefficient bone resorption. Bone marrow transplantation was successful in all patients, and posttransplant osteoclasts showed rescue of a3 subunit immunoreactivity.