Immunohistochemical expression of MAM-3 and MAM-6 antigens in salivary gland tumours

Summary MAM-3 and MAM-6 antigens of human milk fat globule membrane were detected immunohistochemically in 93 cases of salivary gland tumours as well as in normal glands. The antigens were visualized in 10% formalin-fixed paraffin sections. MAM-3 (MoAbs 115G3, 67D11) antigen was distributed in intercalated and striated duct cells of the normal salivary glands, and in luminal tumour cells and squamous metaplastic cells of pleomorphic adenomas. In pleomorphic adenomas the frequency of positive staining with MoAb 67D11 (54/67; 80.6%) was higher than that with MoAb 115G3 (36/67; 53.7%). MAM-6 (MoAbs 115D8, 115F5) antigen was expressed in luminal and lateral borders of serous acinar cells and ductal of the normal glands, and also in luminal borders of tubulo-ductal and glandular structures of salivary gland tumours. Ductal basal cells were characterized by existence of positive staining for MAM-6 antigen, in adenolymphomas MAM-6 antigen was restricted to the basal tumour cells. Some mucous cells of mucoepidermoid tumours were stained specifically with MoAb 115G3, and epidermoid cells of mucoepidermoid carcinomas manifested MAM-6 antigen staining. Immunohistochemical localization of MAM-6 antigen resembled that of epithelial membrane antigen (EMA) detected with MoAb.     

Identification of mutations in the Bruton's tyrosine kinase gene,including a novel genomic rearrangements resulting in large deletion,in Korean X-linked agammaglobulinemia patients

Mutations in the Bruton's tyrosine kinase (BTK) gene are responsible for X-linked agammaglobulinemia (XLA). We identified BTK mutations in six patients with presumed XLA from unrelated Korean families. Four out of six mutations were novel: two missense mutations (P565T, C154Y), a point mutation in a splicing donor site (IVS11+1G>A), and a large deletion (a 6.1-kb deletion including BTK exons 11–18). The large deletion, identified by long-distance PCR, revealed Alu-Alu mediated recombination extended from an Alu sequence in intron 10 to another Alu sequence in intron 18, spanning a distance of 6.1 kb. The two known mutations consisted of one missense (G462D) mutation, and a point mutation in a splicing acceptor site (IVS7−9A>G). This study suggests that large genomic rearrangements involving Alu repeats are few but an important component of the spectrum of BTK mutations.     

Chronic unpredictable stress causes attenuation of serotonin responses in cornu ammonis 1 pyramidal neurons

In the present study, serotonin (5-HT) responses of hippocampal pyramidal cornu ammonis 1 (CA1) neurons were studied in rats subjected twice daily for 21 days to unpredictable stressors. In hippocampal tissue from thus stressed rats mRNA expression of the 5-HT(1A) receptor and mineralo- as well as glucocorticoid receptors were examined with in situ hybridization. On average, stressed rats displayed increased adrenal weight and attenuated body weight gain compared with controls, supporting that the animals had experienced increased corticosterone levels due to the stress exposure. One day after the last stressor, under conditions that corticosterone levels were low (predominant mineralocorticoid receptor activation), the 5-HT(1A) receptor mediated hyperpolarization of CA1 neurons in response to 10 microM 5-HT was significantly reduced compared with controls. Basal membrane properties of CA1 cells in stressed rats were comparable to those of controls. The 5-HT(1A) receptor mRNA expression was not changed after chronic stress exposure, in any of the hippocampal areas. A small but significant increase in mineralocorticoid receptor mRNA expression was observed after stress in the dentate gyrus, while glucocorticoid receptor expression was unchanged. The data indicate that unpredictable stress exposure for 3 weeks results in suppression of 5-HT(1A) receptor-mediated responses, possibly due to posttranslational modification of the receptor.     

Genetic relationship between Streptococcus pneumoniae isolates from nasopharyngeal and cerebrospinal fluid of two infants with Pneumococcal Meningitis

The molecular epidemiology of Streptococcus pneumoniae isolates from carriage and cerebrospinal fluid (CSF) concurrently recovered from the same individual has not yet been reported. By using pulsed-field gel electrophoresis, we demonstrated the genetic linkage among strains from CSF and nasopharynges of two children with pneumococcal meningitis.     

Performance of a commercial, type-specific enzyme-linked immunosorbent assay for detection of herpes simplex virus type 2-specific antibodies in Ugandans

Two hundred forty-eight human immunodeficiency virus (HIV)-positive and 496 HIV-negative subjects in Uganda were tested by HerpeSelect herpes simplex virus type 2 enzyme-linked immunosorbent assay (ELISA) and Western blotting to optimize the ELISA for use in this population. A higher index cutoff value was required for optimal sensitivity and specificity, and overall performance of the assay was not affected by HIV status.     

Co‐occurring medical conditions in adults with Down syndrome: A systematic review toward the development of health care guidelines. Part II

Adults with Down syndrome (DS) represent a unique population who are in need of clinical guidelines to address their medical care. Many of these conditions are of public health importance with the potential to develop screening recommendations to improve clinical care for this population. Our workgroup previously identified and prioritized co‐occurring medical conditions in adults with DS. In this study, we again performed detailed literature searches on an additional six medical conditions of clinical importance. A series of key questions (KQ) were formulated a priori to guide the literature search strategy. Our KQs focused on disease prevalence, severity, risk‐factors, methodologies for screening/evaluation, impact on morbidity, and potential costs/benefits. The available evidence was extracted, evaluated and graded on quality. The number of participants and the design of clinical studies varied by condition and were often inadequate for answering most of the KQ. Based upon our review, we provide a summary of the findings on hip dysplasia, menopause, acquired cardiac valve disease, type 2 diabetes mellitus, hematologic disorders, and dysphagia. Minimal evidence demonstrates significant gaps in our clinical knowledge that compromises clinical decision‐making and management of these medically complex individuals. The creation of evidence‐based clinical guidance for this population will not be possible until these gaps are addressed.     

Evidence for involvement of a tumor suppressor gene on 1p in malignant peripheral nerve sheath tumors

Malignant peripheral nerve sheath tumors (MPNST) are rare soft-tissue malignancies. The genetic basis of these tumors is still poorly understood. Cytogenetic analyses predominantly revealed complex karyotypes, precluding the identification of recurrent chromosomal changes. We report loss of 1p material in a near-diploid karyotype with few or no additional structural chromosome changes in two sporadic cases of MPNST, indicating an important role of 1p loss in MPNST development. In one of these two tumors, a distal 1p deletion (1p31.2 approximately pter) was detected suggesting involvement of a tumor suppressor gene located within this distal region of 1p. Further evidence for recurrent 1p loss in MPNST was obtained by interphase fluorescence in situ hybridization, which showed loss of 1p material in 3 out of 13 tumors. These findings together with data from the literature suggest that loss of a tumor suppressor gene located within distal 1p is implicated in the pathogenesis of MPNST.     

Regulation of gelatinase B in human monocytic and endothelial cells by PECAM-1 ligation and its modulation by interferon-beta.

Platelet endothelial cell adhesion molecule-1 (PECAM-1 or CD31) and gelatinase B are coexpressed at sites of inflammation, where an intense interaction occurs between leukocytes and endothelial cells. To investigate whether a functional link exists between PECAM-1 activation and gelatinase B production, the regulatory role of PECAM-1, IFN-gamma, IFN-beta, LPS, and PMA on the production of gelatinase B (MMP-9) was studied in vitro in normal human umbilical vein endothelial cells (HUVECs), human peripheral blood mononuclear cells (PBMCs), and in a human monocytic leukemia cell line. In THP-1 cells, progelatinase B levels were slightly up-regulated by immobilized PECAM-1-specific monoclonal antibody (mAb) and soluble recombinant PECAM-1 when compared with strong induction by LPS and PMA. IFN-beta inhibited the induced and basal gelatinase B production but had no modulating effect on the expression of PECAM-1. HUVECs mainly produced progelatinase A (proMMP-2). Treatment with LPS and triggering of the endothelial cells with PECAM-1 mAb or recombinant PECAM-1 had no effect on gelatinase A or B production, whereas PMA stimulated the production of progelatinase B. IFN-beta significantly up-regulated the expression of PECAM-1 in HUVECs but did not affect gelatinase secretion. Finally, in PBMCs, progelatinase B production was increased by soluble PECAM-1 mAb, recombinant PECAM-1, LPS, and PMA, whereas IFN-beta reduced gelatinase B secretion. IFN-beta did not alter PECAM-1 expression on PBMCs. Thus, PECAM-1 and gelatinase B are differently regulated in leukocytes and endothelial cells.     

Solubilization and immunological identification of presynaptic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors in the rat hippocampus

Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors have been identified mostly as postsynaptic receptors mediating fast glutamatergic synaptic transmission. However, neurochemical studies based on the modulation of neurotransmitter release have suggested the existence of presynaptic AMPA receptors. We have used a recently described technique that allows a high-purity fractionation of the pre- and postsynaptic proteins of synaptic junctions to evaluate the distribution of the different AMPA receptor subunits in rat hippocampal synapses. Surprisingly, we found very high levels of GluR1- and GluR2/3-like immunoreactivity in the presynaptic fraction, but also in the postsynaptic and extrasynaptic fractions. GluR4-like immunoreactivity was much less abundant but was still detected, predominantly in the postsynaptic fraction. This methodology appears to be far more sensitive than the classical immunogold electron microscopy to determine the localization of synaptic receptors.     

Impairment of a cortical event-related desynchronisation during a bimanual load-lifting task in children with autistic disorder

In autism, the abilities of communication are affected, associated with abnormalities of cognitive, sensorial and motor development. In a previous study based on a load-lifting task, we showed impairment of anticipation in children with autism as evidenced by kinematics and eletromyographic recordings [Neurosci. Lett. 348 (2003) 17]. In the present study, we assessed the cortical counterparts of the use of anticipatory postural adjustments in a group of control children and in a group of children with autism. The tasks required maintaining a stable forearm position despite imposed or voluntary lifting of an object placed either on the controlateral forearm or on a support. We investigated the differences between the two groups of children on the Event-Related Desynchronisation (ERD) which precedes movement onset in adults [Electroencephalogr. Clin. Neurophysiol. 46 (1979) 138]. Electroencephalogram (EEG) power evolution of a 6-8-Hz frequency band was averaged before and after imposed or voluntary movement onset. EEG reactivity of control and autistic children did not differ during the imposed unloading condition, but significant differences appeared in the voluntary unloading situations. Before lifting the object, control children showed an ERD above the left motor areas. An ERD also occurred above the right motor areas when the object was placed on their forearm. This indicates that the ERD can also translate the use of anticipatory postural adjustments. By contrast, children with autism did not show an ERD in the two voluntary situations. This suggests a central deficit of anticipation in both postural and motor control in children with autism.