Detection of human immunodeficiency virus type 1 (HIV-1) in heel prick blood on filter paper from children born to HIV-1-seropositive mothers.

The human immunodeficiency virus type 1 (HIV-1) DNA PCR results of 94 dried blood spot (DBS) samples on filter paper and corresponding venous blood in EDTA obtained from infants born to HIV-1-seropositive mothers were compared. In addition, the results of HIV-1 DNA PCR on DBS and the HIV-1 RNA PCR from plasma of 70 paired samples were compared. A 100% specificity and a 95% sensitivity for HIV-1 DNA PCR on DBS compared with results for venous blood were observed for the 94 paired samples. The results of the DBS HIV-1 DNA PCR and HIV-1 RNA PCR of 70 corresponding plasma samples correlated perfectly (100%). The DBS HIV-1 DNA PCR method proved reliable for HIV-1 detection.     

Histological and ultrastructural appearance of the hydroxyapatite-bone interface

This article describes the histological and ultrastructural appearance of the interface created in the implantation bed, between bone tissue and implants made of dense sintered hydroxyapatite (HA). Biopsies from dog subjects included: a) loaded permucosal dental implants for tooth substitution, b) subperiosteally placed implants for alveolar bone correction, c) endosseously placed dental root implants to retain ridge form following extraction. The light and electron microscopical results show extensive bone apposition on the osseous sides of the implant surfaces. There is an intimate, direct bone contact without any visible interruption. The bone is of normal lamellar type and continuously connected with the trabecular bone. Bone has grown into the finest surface irregularities of the implant. Collagen fibers of the calcified bone matrix are observed within a distance less than 500 A from the implant surface. The thin (20-100 A) electron dense layer at the bone-implant interface resembled the lamina limitans of organic bone matrix, also seen at the inner walls of the osteocytes lacunes. Deposition of bone gives rise to a biologically stable bone-implant interface, without disturbance of the physiological bone turnover. This is seen as very favorable for desired long term fixation of implant to bone.     

Borrelia burgdorferi sensu lato infection in larval Ixodes ricinus (Acari: Ixodidae) feeding on blackbirds in northwestern Italy

Birds belonging to 59 species (n = 1,206) were live captured in Piemonte, northwestern Italy, in 2001. Ixodes ricinus (L.) larvae were collected from 59 birds belonging to nine species, and nymphs were recovered on 79 birds belonging to 10 species. Eurasian blackbirds, Turdus merula L., had significantly higher levels of infestation by ticks than other passerine species. Larval I. ricinus of blackbirds peaked in summer, when prevalence was 39% (95% confidence interval 24.2-55.5) and mean number of ticks per host was 3.3 (1.6-7.2), whereas nymphs peaked in spring, when prevalence was 72.2% (54.8-85.8) and mean number of ticks per host was 6.9 (4.4-10.7). Immature I. ricinus were coincidentally aggregated on blackbirds, with 15 blackbirds feeding 67.4% of nymphs and 40.3% of larvae, and coinfestation by both stages was relatively high in summer: Kappa = 0.64 (0.40-0.88). Borrelia burgdorferi sensu lato was identified by polymerase chain reaction (PCR) in 58.3% (35.9-78.5) of larvae with engorgement ratio > or = 3 that were collected from blackbirds. Larvae that were collected from other passerine species gave negative PCR results. Sixteen of 21 PCR-positive samples belonged to B. garinii (76.2%), and five (23.8%) were Borrelia valaisiana. Results of this study suggest that blackbirds play an important role as hosts for immature I. ricinus and as reservoir of Borrelia garinii in northwestern Italy.     

Allergy to cooked white potatoes in infants and young children: A cause of severe,chronic allergic disease

BACKGROUND: Cases of allergy to cooked potato in children have been reported, some with immediate and others with late reactions. The clinical effects of chronic allergic reactions to potato and the effectiveness of diet on such reactions have not been described previously. OBJECTIVE: We sought to evaluate the importance of cooked potato as an allergenic food in individual cases of atopy in children. METHODS: Eight atopic children were selected on the basis of suspicion of allergy to cooked potatoes: all had potato-specific IgE, 2 of 8 had experienced immediate allergic reactions, and 6 of 8 had eczema that improved with a potato-elimination diet (decrease in severity scoring of atopic dermatis [SCORAD] index of >50%). The patients were evaluated by using skin prick tests with homemade cooked and noncooked potato extracts and with a commercial extract and by using IgE immunoblots from SDS-PAGE patterns of potato extract. Seven patients were challenged with cooked potato. The control group consisted of 9 age-matched atopic children, 8 of them with eczema. RESULTS: The mean SCORAD index decreased from 43.3 before to 11.5 after elimination of potato from the diet. Potato CAP values ranged from 3.71 to greater than 100 kUa/L. Potato challenge results were positive in 7 of 7 patients. Skin prick test responses were positive for cooked potato extracts in 7 of 7 patients, for noncooked extracts in 7 of 7 patients, and for the commercial extract in 8 of 8 patients compared with in 0 of 9, 1 of 9, and 1 of 9 subjects in the control group, respectively. During immunoblotting, 8 of 8 patient sera recognized one or more protein bands compared with 0 of 9 control subject sera. CONCLUSION: Allergy to cooked potatoes is a cause of severe allergic disease, with immediate reactions and eczema in some atopic infants and young children.     

Linkage mapping of a nonspecific form of X-linked mental retardation (MRX53) in a large Pakistani family

Nonspecific X-linked mental retardation is a nonprogressive, genetically heterogeneous condition that affects cognitive function in the absence of other distinctive clinical manifestations. We report here linkage data on a large Pakistani family affected by a form of X-linked nonspecific mental retardation. X chromosome genotyping of family members and linkage analysis allowed the identification of a new disease locus, MRX53. The defined critical region spans approximately 15 cM between DXS1210 and DXS1047 in Xq22.2-26. A LOD score value of 3.34 at no recombination was obtained with markers DXS1072 and DXS8081.     

Fifteen years experience with an in-vitro fertilization surrogate gestational pregnancy programme

The purpose of our study was to review and evaluate retrospectively the experience of an in-vitro fertilization (IVF) surrogate gestational programme in a tertiary care and academic centre. In a 15 year period from 1984 to 1999, a total of 180 cycles of IVF surrogate gestational pregnancy was started in 112 couples. On average, the women were 34.4 +/- 4.4 years of age, had 11.1 +/- 0.72 oocytes obtained per retrieval, 7.1 +/- 0.5 oocytes fertilized and 5. 8 +/- 0.4 embryos subsequently cleaved. Sixteen cycles (8.9%) were cancelled due to poor stimulation. Except for six cycles (3.3%) where there were no embryos available, an average of 3.2 +/- 0.1 embryos was transferred to each individual recipient. The overall pregnancy rate per cycle after IVF surrogacy was 24% (38 of 158), with a clinical pregnancy rate of 19% (30 of 158), and a live birth rate of 15.8% (25 of 158). When compared to patients who underwent a hysterectomy, individuals with congenital absence of the uterus had significantly more oocytes retrieved (P < 0.006), fertilized, cleaved and more embryos available for transfer despite being of comparable age. IVF surrogate gestation is an established, yet still controversial, approach to the care of infertile couples. Take-home baby rates are comparable to conventional IVF over the same 15 year span in our programme. Patients with congenital absence of the uterus responded to ovulation induction better than patients who underwent a hysterectomy, perhaps due in part to ovarian compromise from previous surgical procedures.     

Cloning and functional characterization of a novel connexin expressed in somites of Xenopus laevis.

Connexin-containing gap junctions play an essential role in vertebrate development. More than 20 connexin isoforms have been identified in mammals. However, the number identified in Xenopus trails with only six isoforms described. Here, identification of a new connexin isoform from Xenopus laevis is described. Connexin40.4 was found by screening expressed sequence tag databases and carrying out polymerase chain reaction on genomic DNA. This new connexin has limited amino acid identity with mammalian (<50%) connexins, but conservation is higher (approximately 62%) with fish. During Xenopus laevis development, connexin40.4 was first expressed after the mid-blastula transition. There was prominent expression in the presomitic paraxial mesoderm and later in the developing somites. In adult frogs, expression was detected in kidney and stomach as well as in brain, heart, and skeletal muscle. Ectopic expression of connexin40.4 in HEK293 cells, resulted in formation of gap junction like structures at the cell interfaces. Similar ectopic expression in neural N2A cells resulted in functional electrical coupling, displaying mild, asymmetric voltage dependence. We thus cloned a novel connexin from Xenopus laevis, strongly expressed in developing somites, with no apparent orthologue in mammals.     

L1 knockout mice show dilated ventricles, vermis hypoplasia and impaired exploration patterns

L1 is a neural cell adhesion molecule mainly involved in axon guidance and neuronal migration during brain development. Mutations in the human L1 gene give rise to a complex clinical picture, with mental retardation, neurologic abnormalities and a variable degree of hydrocephalus. Recently, a transgenic mouse model with a targeted null mutation in the L1 gene was generated. These knockout (KO) mice show hypoplasia of the corticospinal tract. Here we have performed further studies of these KO mice including magnetic resonance imaging of the brain, neuropathological analysis and behavioral testing. The ventricular system was shown to be abnormal with dilatation of the lateral ventricles and the 4th ventricle, and an altered shape of the Sylvius aqueduct. Additionally, the cerebellar vermis of the KO mice is hypoplastic. Their exploratory behavior is characterized by stereotype peripheral circling reminiscent of that of rodents with induced cerebellar lesions.      

Prevalence of thermotolerant Campylobacter in pheasants (Phasianus colchicus)

The present study was undertaken with the aim to evaluate the prevalence of thermotolerant Campylobacter spp. in living pheasants in Italy. To achieve this goal, a total of 240 living pheasants, equally shared between female and male birds, were examined. Thermotolerant Campylobacter spp. was isolated in 104 out of 204 (43.3%) living pheasants analysed. Campylobacter coli (100%) and Campylobacter jejuni (13.5%) were identified by polymerase chain reaction. Adult pheasants showed a significantly higher prevalence value (P < 0.05) than younger pheasants.