Search for scalar top and scalar bottom quarks in pp collisions at square root s=1.8 TeV

We have searched for direct pair production of scalar top and scalar bottom quarks in 88 pb-1 of pp collisions at sqrt[s]=1.8 TeV with the CDF detector. We looked for events with a pair of heavy flavor jets and missing energy, consistent with scalar top (bottom) quark decays to a charm (bottom) quark and a neutralino. The numbers of events that pass our selections show no significant deviation from standard model expectations. We compare our results to the next-to-leading order scalar quark production cross sections to exclude regions in scalar quark-neutralino mass parameter space.

So-called malignant and extra-ventricular neurocytomas: reality or wrong diagnosis? A critical review about two overdiagnosed cases

Central neurocytoma (CN) is described as a rare intra-ventricular benign neuronal tumor of the brain. Two primary tumors first diagnosed as malignant and extra-ventricular neurocytomas are reported here. Histologically, the tumor of the first patient, a forty-one-year-old man, consisted of monotonous cells with round nuclei, but no fibrillar background. The second tumor, in a nineteen-year-old girl, showed areas of moderately pleomorphic round cells, with numerous rosettes and ganglion cell differentiation, in an abundant fibrillary network. Both presented calcifications. Mitoses were more frequent in recurrences and spinal locations than in the primaries. All tumors stained strongly for synaptophysin, and GFAP was partly positive in the first case only. Patients received post-surgical radiotherapy and were still alive eight and six years, respectively, after initial surgery. The interpretation of atypical cases, such as ours is not easy: the diagnoses finally retained were oligodendroglioma in the first case and ganglioneuroblastoma in the second case. Furthermore, neurocytomas atypical either by their unusual topographical or histological presentation or by their poor prognosis, have been frequently entitled in this way on synaptophysin positivity. So, we were prompted to reassess the entity of CN, seventeen years after the first description, to re-appreciate the reality of anatomo-clinical variants and to discuss the value of synaptophysin positivity in these tumors. In conclusion, it seems preferable to individualize true classical CN, which has a favorable outcome, from so-called extra-ventricular, atypical and anaplastic, clinically malignant neurocytomas for which complementary treatment is required.

Cellular dumbbell schwannoma of the hypoglossal nerve presenting without hypoglossal nerve palsy

A rare case of cellular schwannoma of the hypoglossal nerve, with intraspinal extension, presenting without any recognisable impairment of the function of the hypoglossal nerve is presented.

Hereditary motor and sensory neuropathy associated with auditory neuropathy in a Gypsy family

In a Slovene Gypsy family of 19 subjects from four generations three patients with clinical characteristics compatible with hereditary motor and sensory neuropathy - Lom (HMSNL). were found They had severe distal and milder proximal muscle atrophy and weakness with areflexia of myotatic jerks. Two had facial weakness at the time when already wheelchair bound. All sensory modalities were affected distally in the limbs. Sluggish pupillary responses to light and convergence were found. They had skeletal abnormalities. One patient had polydactily on the hand. Nerve conduction studies were compatible with demyelinative polyneuropathy. Nerve biopsy showed mainly axonal loss without hypertrophic changes. Auditory neuropathy was diagnosed in all of them. None of the patients had duplication of 17p1.2-12 or point mutations in the Protein zero. Peripheral myelin protein and Connexin32 genes. Similar disorder that mapped to 8q24 was previously described in some Bulgarian and Italian Gypsy families. Members of our family may suffer from the same hereditary disease and may carry the same ancestor mutation, which was in the past spread in European Gypsy populations.

Coreceptor usage and RANTES sensitivity of non-syncytium-inducing HIV-1 isolates obtained from patients with AIDS

OBJECTIVES

The biologic phenotype of HIV-1 primary isolates obtained from approximately 50% of patients who progress to AIDS switches from non-syncytium-inducing (NSI) to syncytium-inducing (SI). We evaluated possible associations between virus coreceptor usage, sensitivity to inhibition by beta-chemokines, and disease progression of patients who continue to yield NSI isolates after developing AIDS.

STUDY DESIGN/METHODS

Sequential virus isolates were analyzed for biologic phenotype using the MT-2 cell assay, for sensitivity to beta-chemokines using RANTES inhibition, and for coreceptor usage using U87.CD4 and GHOST.CD4 cells expressing different chemokine/orphan receptors or donor peripheral blood mononuclear cells (PBMC) defective in CCR5 expression. In addition, the env V3 region was sequenced and the length of the V2 region determined.

RESULTS

All NSI isolates, regardless of patient status at time of isolation, were dependent on CCR5 expression for cell entry. Furthermore, there was no indication of broadened coreceptor usage of NSI isolates obtained from persons with late-stage AIDS. A majority of NSI isolates remained RANTES sensitive; however, virus variants with reduced sensitivity were observed. The V2 lengths and the V3 sequences exhibited no or minor changes at analysis of sequential NSI isolates.

CONCLUSIONS

Our data suggest that NSI isolates obtained from AIDS patients remain CCR5 dependent (ie, R5) and, in many cases, also remain sensitive to RANTES inhibition. However, virus variants with decreased sensitivity to RANTES inhibition may evolve during disease progression, not only as a result of a switch from NSI to SI but also in patients who develop AIDS while continuing to maintain R5 isolates.

Hereditary auditory, vestibular, motor, and sensory neuropathy in a Slovenian Roma (Gypsy) kindred

Members of a Roma (Gypsy) family with hereditary motor and sensory peripheral neuropathy (HMSN) and concomitant auditory and vestibular cranial neuropathies were identified in Kocevje, Slovenia. The illness begins in childhood with a severe and progressive motor disability and the deafness is delayed until the second decade. There are no symptoms of vestibular dysfunction. The family structure is consistent with an autosomal recessive pattern of inheritance and the genetic locus for the disorder is linked to the same region of chromosome 8q24 as other Roma families with HMSN and deafness from Lom, Bulgaria (HMSN-Lom). The present study shows that the deafness is caused by a neuropathy of the auditory nerve with preserved measures of cochlear outer hair cell function (otoacoustic emissions and cochlear microphonics) but absent neural components of auditory brainstem potentials. The hearing loss affects speech comprehension out of proportion to the pure tone loss. Vestibular testing showed absence of caloric responses. Physiological and neuropathological studies of peripheral nerves were compatible with the nerve disorder contemporaneously affecting Schwann cells and axons resulting in both slowed nerve conduction and axonal loss. Genetic linkage studies suggest a refinement of the 8q24 critical region containing the HMSN-Lom locus that affects peripheral motor and sensory nerves as well as the cranial auditory and vestibular nerves.

Estrus cycle and gastric lesions in individual- and group-stressed female rats

The aim of the present study was to analyze the influence of the estrus cycle on the development of cold restraint-induced gastric lesions in single- and group-stressed female rats. Therefore, adult female Wistar rats, in different phases of the estrus cycle (proestrus, estrus, metestrus and diestrus), were restrained individually or in groups (two, three, six or nine rats) and exposed to a temperature of 4 degrees C for 2 h. The comparison between stressed female rats in different phases of the estrus cycle indicated that gastric pathology was significantly higher in estrus phase as compared to the other phases of the estrus cycle. The intensity of stress-induced gastric pathology was either not changed (estrus), moderately decreased (proestrus and metestrus) or highly decreased (diestrus) by increasing the number of concomitantly exposed rats to cold restraint. The vulnerability to cold restraint-induced stress ulcer rose as followed: proestrus < metestrus < diestrus < estrus. It could be concluded that female rats are more vulnerable to cold restraint-induced stress ulcer in estrus period and that in this phase, social interaction did not made any significant influence on the stress induced gastric lesions.

Disease modifying and immunomodulatory effects of high dose 1 alpha (OH) D3 in rheumatoid arthritis patients

OBJECTIVE

Vitamin D analogues such as 1 alpha (OH) D3 (alphacalcidiol) have a possible physiological paracrine effect on cell proliferation and differentiation. Experimentally established possibilities to prevent autoimmune diseases suggest that alphacalcidiol may have therapeutic value as an immunomodulatory agent in patients with rheumatoid arthritis.

METHODS

We organized a 3-month open-label trial on 19 patients being treated with standard DMARD therapy for acute RA. They were divided into 2 subgroups, those with highly active RA and those with moderately active RA. Their regular drug regimen was maintained during the trial and oral alphacalcidiol 2 micrograms/day was added. Therapy results were evaluated by ESR, CRP, morning stiffness, the Richie index, and the Lee index. Immunomodulatory effects were investigated by measuring lymphocyte proliferation and apoptosis both in the patients and in vitro in 10 nM alphacalcidiol-supplemented culture medium.

RESULTS

After 3 months, high dose oral alphacalcidiol therapy showed a positive effect on disease activity in 89% of the patients (45% or 9 pts. with complete remission and 44% or 8 pts. with a satisfactory effect). Only two patients (11%) showed no improvement, but no new symptoms occurred. No side effects were observed.

CONCLUSION

These results suggest that alphacalcidiol is a powerful immunomodulatory agent with fairly low hypercalcemic activity. Clinical improvement was strongly correlated with the immunomodulating potential of this agent. We noticed dual effects on lymphocyte proliferation and apoptosis according to the prior cell activation state. Alphacalcidiol could therefore possibly be used as an adjunct therapy with DMARDs in patients with rheumatoid arthritis.

Classification of tetraplegics through automatic movement evaluation

The general problem of classification of functional movements in humans with spinal cord injuries requires the following questions to be answered: what are the essential kinematic parameters that we have to observe during the movement? Is it possible to estimate preserved motor skills based on kinematics? Which computational method for identification is suited to geometric feature analysis? To answer these questions we have developed the methodology which has two phases: (1) recordings of a series of specified arm movements; and (2) custom made software for graphical presentation of arm movements and the design of wavelet and neural networks for movement classification. The proposed protocol is automated and both graphical presentation and neural networks allow easy interpretation of the instrumented assessment to accomplish automatic classification of arm movements in tetraplegics. The protocol was evaluated on 16 spinal cord injury (SCI) patients and seven healthy control subjects for three different arm movements. The classification rate yielded results in the range 46-100% for movement trials that were tested. The application of neural networks for classification of arm movements is completed with results using different neural networks: backpropagation, radial basis, recurrent (Elman), self-organizing and Learning Vector Quantization (LVQ).

The leukotriene B4 receptor functions as a novel type of coreceptor mediating entry of primary HIV-1 isolates into CD4-positive cells

The recently cloned human chemoattractant receptor-like (CMKRL)1, which is expressed in vivo in CD4-positive immune cells, has structural homology with the two chemokine receptors C-C chemokine receptor (CCR)5 and C-X-C chemokine receptor (CXCR)4, which serve as the major coreceptors necessary for fusion of the HIV-1 envelope with target cells. In view of the structural similarity, CMKRL1 was tested for its possible function as another HIV-1 coreceptor after stable expression in murine fibroblasts bearing the human CD4 receptor. The cells were infected with 10 primary clinical isolates of HIV-1, and entry was monitored by semiquantitative PCR of viral DNA. The efficiency of the entry was compared with the entry taking place in CD4-positive cells expressing either CCR5 or CXCR4. Seven of the isolates used CMKRL1 for viral entry; they were mainly of the syncytium-inducing phenotype and also used CXCR4. Entry efficiency was higher with CMKRL1 than with CXCR4 for more than half of these isolates. Three of the ten isolates did not use CMKRL1; instead, entry was mediated by both CCR5 and CXCR4. The experiments thus indicate that CMKRL1 functions as a coreceptor for the entry of HIV-1 into CD4-positive cells. In the course of this study, leukotriene B4 was shown to be the natural ligand for this receptor (now designated BLTR), which therefore represents a novel type of HIV-1 coreceptor along with the previously identified chemokine receptors. BLTR belongs to the same general chemoattractant receptor family as the chemokine receptors but is structurally more distant from them than are any of the previously described HIV-1 coreceptors.

Gp120 sequence variation in brain and in T-lymphocyte human immunodeficiency virus type 1 primary isolates

OBJECTIVE

We sought to identify genetic determinants within human immunodeficiency virus type 1 (HIV-1) gp120 that differentiate viral species in brain from those in lymphocytes.

STUDY DESIGN/METHODS

Polymerase chain reaction (PCR) was used to amplify gp120 genes from paired brain and T-cell isolates from two infants and two adults with dementia. Amplimers were molecularly cloned and sequenced.

RESULTS

The degrees of amino acid divergence between brain and T-cell clones for the two adults were 7.7% and 8.6% and, for the two infants, 2.4% and 2.7%. For one adult and one infant, divergence was greater among brain cell clones than T-cell clones. In the adults, a 3-amino acid insertion, located similarly within V4 and encoding asparagine residues, was identified in the T-cell clones.

CONCLUSIONS

HIV-1 genetic variation within brain cells is not necessarily restricted compared with that in blood lymphocytes. The species in brain cells can be distinguished from those in lymphocytes by determinants within V4. These differences suggest that immune-mediated selection ongoing within lymphoid cell compartments may not occur within brain.

Sensitivity to inhibition by beta-chemokines correlates with biological phenotypes of primary HIV-1 isolates

Primary HIV-1 isolates were evaluated for their sensitivity to inhibition by beta-chemokines RANTES (regulated upon activation, normal T-cell expressed and secreted), macrophage inflammatory protein 1 alpha (MIP-1 alpha), and MIP-1 beta. Virus isolates of both nonsyncytium-inducing (NSI) and syncytium-inducing (SI) biological phenotypes recovered from patients at various stages of HIV-1 infection were assessed, and the results indicated that only the isolates with the NSI phenotype were substantially inhibited by the beta-chemokines. More important to note, these data demonstrate that resistance to inhibition by beta-chemokines RANTES, MIP-1 alpha, and MIP-1 beta is not restricted to T cell line-adapted SI isolates but is also a consistent property among primary SI isolates. Analysis of isolates obtained sequentially from infected individuals in whom viruses shifted from NSI to SI phenotype during clinical progression exhibited a parallel loss of sensitivity to beta-chemokines. Loss of virus sensitivity to inhibition by beta-chemokines RANTES, MIP-1 alpha, and MIP-1 beta was furthermore associated with changes in the third variable (V3) region amino acid residues previously described to correlate with a shift of virus phenotype from NSI to SI. Of interest, an intermediate V3 genotype correlated with a partial inhibition by the beta-chemokines. In addition, we also identified viruses sensitive to RANTES, MIP-1 alpha, and MIP-1 beta of NSI phenotype that were isolated from individuals with AIDS manifestations, indicating that loss of sensitivity to beta-chemokine inhibition and shift in viral phenotype are not necessarily prerequisites for the pathogenesis of HIV-1 infection.