Neuroradiology and clinical aspects of Usher syndrome

We describe the neurological evaluation and MRI analysis of 30 patients, belonging to 16 families with Usher syndrome (US) type I and type II (US1 and US2). In addition to the classic visual and audiological abnormalities seen in these patients, we observed abnormal gait in 88.9% of US1 and in 66.7% of US2 patients and abnormal coordination in 33.4% of US1, and in 58.3% of US2. Borderline mental retardation, depression or bipolar affective disorder were observed in 16.7% of US1 and 33.3% of US2 patients. MRI analysis showed cerebellar abnormalities in 50% of US 1 and 75% of US2 patients, but no clear correlation was observed between structural abnormalities and clinical findings. A pattern for the MRI classification of US patients is suggested.     

Impact of Breast Density on Computer-Aided Detection in Full-Field Digital Mammography

The goal of this study was to evaluate the performance of a computer-aided detection (CAD) system in full-field digital mammography (Senographe 2000D, General Electric, Buc, France) in finding out carcinomas depending on the parenchymal density. A total of 226 mediolateral oblique (MLO) and 186 craniocaudal (CC) mammographic views of histologically proven cancers were retrospectively evaluated with a digital CAD system (ImageChecker V2.3 R2 Technology, Los Altos, CA, USA). Malignant tumors were detected correctly by CAD in MLO view in 84.85% in breasts with parenchymal tissue density of the American College of Radiology (ACR) type 1, in 70.33% of the ACR type 2, in 68.12% of the ACR type 3, and in 69.70% of the ACR type 4. For the CC view, similar results were found according to the ACR types. Using the chi-square and McNemar tests, there was no statistical significance. However, a trend of better detection could be seen with decreasing ACR type. In conclusion, there seems to be a tendency for breast tissue density to affect the detection rate of breast cancer when using the CAD system.     

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.     

Brucella lumazine synthase elicits a mixed Th1-Th2 immune response and reduces infection in mice challenged with Brucella abortus 544 independently of the adjuvant formulation used

The immunogenicity and protective efficacy of recombinant lumazine synthase from Brucella spp. (rBLS) administered with different adjuvants was evaluated in mice. Mice were immunized with rBLS in the absence or the presence of aluminum hydroxide gel (BLS-Al), monophosphoryl lipid A (BLS-MPA), or incomplete Freund's adjuvant (BLS-IFA). rBLS per se induced a vigorous immunoglobulin G (IgG) response, with high titers of IgG1 as well as IgG2. All the adjuvants increased this response; the BLS-IFA formulation was the most effective at inducing BLS-specific IgG antibodies. In addition, after in vitro stimulation with rBLS, spleen cells from BLS-IFA-, BLS-Al-, or BLS-MPA-immunized mice proliferated and produced interleukin-2 (IL-2), gamma interferon (IFN-gamma), IL-10, and IL-4, suggesting the induction of a mixed Th1-Th2 response. Immunization with rBLS protected mice against challenge with B. abortus 544. The levels of protection in the spleen were similar for all adjuvants, but only BLS-Al and BLS-IFA were effective in the liver. Our results indicate that BLS might be a useful candidate for the development of subunit vaccines against brucellosis, since it elicits antigen-specific cellular responses, with production of IFN-gamma and protection, independently of the adjuvant formulation used.     

Psychopathological traits and 5-HT2A receptor promoter polymorphism (-1438 G/A) in patients suffering from Anorexia Nervosa and Bulimia Nervosa

Various studies have evaluated the possible role of the -1438G/A polymorphism within the 5-HT2A receptor gene in the susceptibility to Eating Disorders (EDs). One hundred and forty-eight ED patients (EDp) and 89 control subjects were interviewed by means of the Eating Disorder Examination (EDE) and analyzed for distribution of the -1438G/A polymorphism. Patients with the AA genotype suffering from Anorexia Nervosa and Bulimia Nervosa showed higher Weight and Shape Concern (P = 0.003 and P = 0.010, respectively) scores and greater overall severity of the ED psychopathology (EDE total score) (P = 0.012). The obtained preliminary data suggest the use of dimensional psychopathological measures in ED genetic studies.     

Blockade of pulmonary stretch receptors reinforces diaphragmatic activity during high-frequency oscillatory ventilation

During apneic periods elicited by high-frequency oscillatory ventilation (HFOV) a tonic diaphragmatic activity was observed, contrasting with the absence of diaphragmatic activity during apnea induced by lung inflation. To clarify the mechanism underlying the persistence of the diaphragmatic activity during HFOV-induced arrest of breathing the reflex responses to short periods of HFOV, and to periods of lung inflation with airway pressure (P _aw) equal to the meanP _aw and/or to maximalP _aw during HFOV were examined both before and after the blockade of slowly adapting stretch receptors (SR) by inhalation of sulphur dioxide (SO₂) in anaesthetized rabbits. In animals with intact SR, the HFOV-induced reflex apnea lasted longer than that induced by lung inflation, the associated diaphragmatic activity being in the most cases higher than the diaphragmatic activity during quiet expiration; inflation, however, completely inhibited diaphragmatic activity. After blockade of SR, spontaneous breathing continued during periods of lung inflation, i.e., the Hering-Breuer inflation reflex was abolished, whereas HFOV still led to a cessation of spontaneous breathing, the associated diaphragmatic activity even exceeding the level observed during quiet inspiration. From these results we conclude that only one part of the reflex response to HFOV is due to SR-stimulation and that in addition other vagal pulmonary receptors (irritant-and/or C-fibre-receptors) are involved. The stimulation of the latter counterbalances the concomitant stimulation of SR, giving rise to the tonic activity of the diaphragm.     

The morphology of immune reactions in normal, thymectomized and reconstituted mice: I. The response to sheep erythrocytes

The response to sheep red blood cells has been studied in the lymph nodes draining their site of injection in normal mice, and in thymectomized, irradiated, bone-marrow injected mice with and without a reconstituting thymus graft. By using a chromosome marker to differentiate between cells derived from the bone-marrow and thymus graft it has proved possible to show that the immune response should be thought of in terms of at least two cell populations. Cells of thymic origin are stimulated to mitotic activity in the interfollicular cortex, and their activity precedes both antibody production and morphological signs of activity in the follicular regions. Mitotic divisions of cells of bone-marrow origin reached a peak a day later than did the thymic cells and their activity was sustained. Follicular enlargement and germinal centre production were coincident in time both with antibody production and bone-marrow cell mitotic activity. Lymph nodes of animals lacking a thymic influence showed only minor changes after antigenic stimulation and these were restricted to the follicular regions. There appeared to be only a small quantitative difference between the responses of normal and of reconstituted animals.     

Five-test simple scheme for species-level identification of clinically significant coagulase-negative staphylococci

A working scheme developed in our laboratory for identification (by species group and species) of coagulase-negative staphylococci (CNS) was evaluated with 201 consecutive isolates and then validated by using the reference method of Kloos and Schleifer (W. E. Kloos and K. H. Schleifer, J. Clin. Microbiol. 1:82-88, 1975). This five-test simple scheme (referred to here as the simple scheme) combines the novobiocin susceptibility test with tests for urease, pyrrolidonyl arylamidase, ornithine decarboxylase, and aerobic acid from mannose. The addition of one or two tests within a particular species group could then positively identify the isolate. Two commercial systems, Staph-Zym (Rosco) and API-Staph (bioMérieux), along with results obtained by using Rosco diagnostic tablets (nongrowth tests), were also compared with the reference method. One isolate could not be identified even by the reference method. Of the remaining 200 strains, 191 (95.5%) strains were correctly identified with Staph-Zym and 171 strains (85.5%) were correctly identified with API-Staph. The most frequent clinical CNS species isolated were Staphylococcus epidermidis (50.5%), S. haemolyticus (18.5%), S. saprophyticus subsp. saprophyticus (16.0%), S. lugdunensis (6.0%), and S. warneri (2.5%). The simple scheme validated with the reference method has demonstrated an excellent correlation in the identification of the three most frequent species isolated: S. epidermidis, S. haemolyticus, and S. saprophyticus subsp. saprophyticus. With the simple scheme, identification of CNS was possible within 24 h after the enzymatic tests were used, whereas up to 72 h is necessary for the growth tests. This methodology would be very useful in any clinical microbiology laboratory for the presumptive identification of CNS species groups and species.     

Polymorphic nucleotide within the promoter of nitrate reductase (NarGHJI) is specific for Mycobacterium tuberculosis

Mycobacterium tuberculosis rapidly reduces nitrate, leading to the accumulation of nitrite. This characteristic served for the past 40 years to differentiate M. tuberculosis from other members of the Mycobacterium tuberculosis complex (MTBC), such as Mycobacterium bovis (non-BCG [referred to here as simply "M. bovis"]), Mycobacterium bovis BCG, Mycobacterium africanum, or Mycobacterium microti. Here, a narG deletion in M. tuberculosis showed that rapid nitrite accumulation of M. tuberculosis is mediated by narGHJI. Analysis of narG mutants of M. bovis and M. bovis BCG showed that, as in M. tuberculosis, nitrite accumulation was mediated by narGHJI, and no other nitrate reductase was involved. However, in contrast to M. tuberculosis, accumulation was delayed for several days. Comparison of the narGHJI promoter revealed that, at nucleotide -215 prior to the start codon of narG, M. tuberculosis carried a thymine residue, whereas the bovine mycobacteria carried a cytosine residue. Using LightCycler technology we examined 62 strains of M. tuberculosis, M. bovis, M. bovis BCG, M. microti, and M. africanum and demonstrated that this single nucleotide polymorphism was specific for M. tuberculosis. For further differentiation within the MTBC, we included, by using LightCycler technology, the previously described analysis of oxyR polymorphism, which is specific for the bovine mycobacteria, and the RD1 polymorphism, which is specific for M. bovis BCG. Based on these results, we suggest a LightCycler format for rapid and unambiguous diagnosis of M. tuberculosis, M. bovis, and M. bovis BCG.