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Biomedical subjects

M R Wallace

Publications and source records attributed to M R Wallace.

At least 55 records · Page 3Linked to original sources
PubMed1998

Newly described form of X-linked arthrogryposis maps to the long arm of the human X chromosome.

Arthrogryposis is a heterogeneous birth defect characterized by limitation of movement at multiple joints. One in 3,000 infants is born with arthrogryposis, and at least a third of these cases have a genetic cause. Four distinct types of X-linked arthrogryposis have been reported, and a severe lethal form recently was mapped to Xpll.3-qll.2. We now report an extended family affected with a novel variant of X-linked arthrogryposis that involves only the lower limbs. Linkage analysis with polymorphic DNA markers maps the disease locus in this unique family to the long arm of the human X chromosome between DXS1220 and DXS1205 in Xq23-27.

Alleles↗
PubMed1998

Progressive cerebral volume loss in human immunodeficiency virus infection: a longitudinal volumetric magnetic resonance imaging study. HIV Neurobehavioral Research Center Group.

OBJECTIVE: To compare rates and anatomical patterns of brain atrophy during 3 stages of human immunodeficiency virus (HIV) disease. DESIGN: Comparisons of multiple serial brain magnetic resonance images in men without HIV infection and HIV-infected men in Centers for Disease Control and Prevention (CDC, Atlanta, Ga) stages A, B, and C. SETTING: Longitudinal cohort study of the San Diego HIV Neurobehavioral Research Center, San Diego, Calif. PARTICIPANTS: Eighty-six HIV-1-positive (HIV-positive) and 23 HIV-negative men who were similar in age and risk group. The number of HIV-positive men in each CDC stage was as follows: A, 33; B, 19; C, 34. All HIV-positive men were free of clinically detectable opportunistic neurologic illness. MAIN OUTCOME MEASURES: Regional volumes of serial magnetic resonance images converted to standardized slope estimates of change in regional volumes of interest. RESULTS: Medically asymptomatic men (CDC stage A) and medically symptomatic men (CDC stage C) had more rapid loss of cortical tissues than did HIV-negative men as manifested by higher slopes (Tukey honestly significant difference test, P=.02 and P=.001, respectively) for cortical fluid volume. Accelerated ventricular volume enlargement occurred only in men with CDC stage C disease. Reduction in the volume of white matter was accelerated in participants with CDC stage C disease compared with participants with CDC stage A disease. Of the gray matter regions, only the caudate nucleus sustained accelerated volume loss during CDC stage C disease. Participants whose systemic disease progressed to a higher CDC stage had significantly accelerated ventricular volume increases and caudate atrophy. Rates of cortical and subcortical fluid volume increases and reductions in the volumes of white matter and the caudate nucleus were significantly related to the rate of decline in the CD4+ lymphocyte count. CONCLUSIONS: In the absence of cerebral opportunistic disease, HIV infection causes progressive atrophy within the gray and white matter in the brain. These changes were most severe in the most advanced stage of disease but were evident even in medically asymptomatic HIV-positive persons. Within the gray matter, the caudate nucleus exhibited progressive volume loss linked to disease stage and the rate of decline of the CD4+ cell count. Structural brain changes can begin in the early stages of HIV infection and accelerate during advanced illness.

Adult↗
PubMed1998

A novel mutation (V191G) in a German-British type 1 Gaucher disease patient. Mutations in brief no. 131. Online.

Gaucher disease results from mutations in the glucocerebrosidase gene located on human chromosome 1q21. Three clinical forms of Gaucher disease have been described: type 1, nonneuropathic; type 2, acute neuropathic; and type 3, subacute neuropathic. We have identified a novel mutation in a German-British patient with type 1 Gaucher disease which results in V191G of the glucocerebrosidase polypeptide. Because the mutation abolishes a HphI cleavage site, its presence was confirmed by HphI RFLP analysis of PCR-amplified genomic DNA. In the second allele of the patient, the mutation identified was g.5841A G(N370S). Sequence analysis of the remainder of the coding region of the gene as well as the exon-intron boundaries showed identity to normal controls. Because mutation N370S has so far been found only in type 1 Gaucher disease and postulated to result in mild clinical presentation, and since the clinical course of this patient has been relatively mild with minimal skeletal involvement, we speculate that the V191G/N370S genotype may also result in good prognosis.

Chromosomes, Human, Pair 1↗
PubMed1998

Once weekly azithromycin therapy for prevention of Mycobacterium avium complex infection in patients with AIDS: a randomized, double-blind, placebo-controlled multicenter trial.

We conducted a randomized, double-blind, placebo-controlled multicenter trial of azithromycin (1,200 mg once weekly) for the prevention of Mycobacterium avium complex (MAC) infection in patients with AIDS and a CD4 cell count of < 100/mm3. In an intent-to-treat analysis through the end of therapy plus 30 days, nine (10.6%) of 85 azithromycin recipients and 22 (24.7%) of 89 placebo recipients developed MAC infection (hazard ratio, 0.34; P = .004). There was no difference in the ranges of minimal inhibitory concentrations of either clarithromycin or azithromycin for the five breakthrough (first) MAC isolates from the azithromycin group and the 18 breakthrough MAC isolates from the placebo group. Of the 76 patients who died during the study, four (10.5%) of 38 azithromycin recipients and 12 (31.6%) of 38 placebo recipients had a MAC infection followed by death (P = .025). For deaths due to all causes, there was no difference in time to death or number of deaths between the two groups. Episodes of non-MAC bacterial infection per 100 patient years occurred in 43 azithromycin recipients and 88 placebo recipients (relative risk, 0.49; 95% confidence interval, 0.33-0.73). The most common toxic effect noted during the study was gastrointestinal, reported by 78.9% of azithromycin recipients and 27.5% of placebo recipients. Azithromycin given once weekly is safe and effective in preventing disseminated MAC infection, death due to MAC infection, and respiratory tract infections in patients with AIDS and CD4 cell counts of < 100/mm3.

AIDS-Related Opportunistic Infections↗
PubMed1998

Atypical Pneumocystis carinii infection in AIDS: massive cervical lymphadenitis and fever of unknown origin.

Pulmonary Pneumocystis carinii infections are relatively common in patients with the acquired immunodeficiency syndrome (AIDS). Extrapulmonary pneumocystis is a less common manifestation, particularly when it occurs without concurrent Pneumocystis carinii pneumonia. Disseminated pneumocystis is most commonly found in lymph nodes, the liver, and the spleen and may result in nonspecific debilitating illness, which is often overlooked in the absence of pulmonary symptoms. We present the case of an AIDS patient who had massive cervical pneumocystis lymphadenitis and minimal pulmonary infiltrates of undetermined etiology and a clinical picture of severe wasting and fever of unknown origin.

AIDS-Related Opportunistic Infections↗
PubMed1998

In vitro p24 antigen-stimulated lymphocyte proliferation and beta-chemokine production in human immunodeficiency virus type 1 (HIV-1)-seropositive subjects after immunization with an inactivated gp120-depleted HIV-1 immunogen (Remune).

We examined the effect of immune stimulation by a human immunodeficiency virus type 1 (HIV-1) immunogen (Remune) compared to a non-HIV vaccine (influenza) on HIV-1-specific immune responses in HIV-1-seropositive subjects. HIV-1 p24 antigen-stimulated lymphocyte proliferation was not augmented after immunization with the influenza vaccine. In contrast, subjects increased their lymphocyte proliferative responses to p24 antigen after one immunization with HIV-1 immunogen (Remune) (gp120-depleted inactivated HIV-1 in incomplete Freund's adjuvant). Furthermore, p24 antigen-stimulated beta-chemokine production (RANTES, MIP-1alpha, MIP-1beta) was also augmented after immunization with the HIV-1 immunogen but not influenza vaccine. Taken together, these results suggest that in this cohort, HIV-specific immune responses to p24 antigen can be augmented after immunization with an HIV-1 immunogen. The ability to upregulate immune responses to the more conserved core proteins may have important implications in the development of immunotherapeutic interventions for HIV-1 infection.

AIDS Vaccines↗
PubMed1998

Constitutional and mosaic large NF1 gene deletions in neurofibromatosis type 1.

A set of neurofibromatosis type 1 (NF1) patients was screened for large NF1 gene deletions by comparing patient and parent genotypes at 10 intragenic polymorphic loci. Of 67 patient/parent sets (47 new mutation patients and 20 familial cases), five (7.5%) showed loss of heterozygosity (LOH), indicative of NF1 gene deletion. These five patients did not have severe NF1 manifestations, mental retardation, or dysmorphic features, in contrast to previous reports of large NF1 deletions. All five deletions were de novo and occurred on the maternal chromosome. However, two patients showed partial LOH, consistent with somatic mosaicism for the deletion, suggesting that mosaicism may be more frequent in NF1 than previously recognised (and may have bearing on clinical severity). We suggest that large NF1 deletions (1) are not always associated with unusual clinical features, (2) tend to occur more frequently on maternal alleles, and (3) are an important mechanism for constitutional and somatic mutations in NF1 patients.

Adult↗
PubMed1997

Reliability of a history of previous varicella infection in adults.

CONTEXT: Apparent second episodes of varicella are reported in immunocompetent hosts, but laboratory confirmation of prior immune status has rarely been possible. OBJECTIVE: To evaluate adult patients with varicella who claimed to have had previous varicella to determine whether they had true second episodes or primary cases with inaccurate clinical histories. DESIGN: Adult subjects with varicella who enrolled in an antiviral treatment trial were interviewed about a history of varicella. The clinical course of varicella was documented prospectively in all subjects. Serum samples that predated the acute illness were obtained from the US Navy's central serum storage facility for subjects who reported a previous episode of varicella. These stored samples were tested in parallel by enzyme-linked immunosorbent assay, latex agglutination, and Western blot for IgG antibodies to varicella-zoster virus (VZV). PARTICIPANTS: Twenty military personnel with varicella and a history of the disease. SETTING: A military hospital in San Diego, Calif. MAIN OUTCOME MEASURE: Presence or absence of antibodies to VZV. RESULTS: Twenty (10.8%) of 184 adults with serologically confirmed acute varicella reported a prior history of varicella. The clinical course of these 20 patients did not differ from those with no history of varicella. Serum samples that had been collected a mean of 12.4 months (median, 12 months; range, 3 days to 34 months) before the incident episode were available for 19 subjects. All 19 serum samples lacked IgG antibodies to VZV. CONCLUSION: A history of previous varicella infection in adults with varicella may not be reliable. True second episodes of varicella are probably rare in immunocompetent adults.

Adult↗
PubMed1997

Effect of immunization with an inactivated gp120-depleted HIV-1 immunogen on beta-chemokine and cytokine production in subjects with HIV-1 infection.

OBJECTIVE: To measure beta-chemokine and cytokine production in HIV-1-infected subjects undergoing treatment with HIV-1 immunogen (REMUNE). DESIGN: Open label treatment study. METHODS: beta-Chemokine and cytokine production in peripheral blood mononuclear cell (PBMC) culture. RESULTS: Interferon-gamma production (p = 0.04) and lymphocyte proliferation (p = 0.001) to HIV-1 antigen-stimulated PBMCs increased after immunization with the HIV-1 immunogen. A correlation was demonstrated after immunization between HIV-1 antigen-stimulated lymphocyte proliferation and interferon-gamma levels (r = 0.53, p = 0.04). No significant change after immunization was seen for interleukin-4 production. A significant increase in mean levels of HIV-1 antigen-stimulated RANTES (i.e., regulated upon, activation normal T-cell expressed and secreted), was evident 1 month after immunization (p = 0.002) and remained elevated 3 months after immunization. RANTES production was decreased in CD8-depleted PBMC cultures. Mean serum HIV-1 RNA copy numbers and CD4 cell counts remained stable after immunization (p > 0.5). A correlation was demonstrated between HIV-1 antigen-stimulated interferon-gamma and RANTES production (r = 0.54, p = 0.002). CONCLUSIONS: This report describes an augmentation of beta-chemokines and TH1-type cytokines from PBMCs after immunization with the HIV-1 immunogen.

CD4 Lymphocyte Count↗
PubMed1997

Physical mapping of the chromosome 7 breakpoint region in an SLOS patient with t(7;20) (q32.1;q13.2).

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disorder characterized by multiple congenital anomalies and mental retardation. SLOS has an associated defect in cholesterol biosynthesis, but the molecular genetic basis of this condition has not yet been elucidated. Previously our group reported a patient with a de novo balanced translocation [t(7;20)(q32.1;q13.2)] fitting the clinical and biochemical profile of SLOS. Employing fluorescence in situ hybridization (FISH), a 1.8 Mb chromosome 7-specific yeast artificial chromosome (YAC) was identified which spanned the translocation breakpoint in the reported patient. The following is an update of the on-going pursuit to physically and genetically map the region further, as well as the establishment of candidate genes in the 7q32.1 breakpoint region.

Chromosome Mapping↗
PubMed1997

Neurocognitive impairment is an independent risk factor for death in HIV infection. San Diego HIV Neurobehavioral Research Center Group.

OBJECTIVE: To determine if mortality is increased in individuals with human immunodeficiency virus type 1 (HIV-1)-associated neurocognitive disorders less severe than frank dementia. DESIGN: A prospective cohort study; median duration of follow-up was 2.4 years. Kaplan-Meier analysis and Cox proportional hazards models were used to compare survival times according to neurocognitive classification. SETTING: University-based research unit. PARTICIPANTS: A volunteer sample of 414 individuals seropositive for HIV-1. Subjects were classified at their baseline evaluation as neuropsychologically (NP) normal or abnormal (impaired in > or = 2 NP test domains). A subgroup of NP abnormal subjects met operational criteria for HIV-associated minor cognitive motor disorder; the remaining subjects were designated NP impaired. Subjects with frank dementia were excluded. MAIN OUTCOME MEASURE: Mortality. RESULTS: At the baseline evaluation, 256 (62%) of 414 subjects were designated normal; 109 (26%). NP impaired; and 49 (12%), minor cognitive motor disorder. One hundred six participants (26%) died during follow-up. Compared with the NP normal group, the unadjusted relative risk (RR) of death for all NP abnormal subjects (minor cognitive motor disorder and NP impaired) was significantly increased (RR, 1.7; 95% confidence interval [CI], 1.2-2.6; P < .005). After adjusting for concurrently measured predictors of survival (CD4 lymphocyte counts, Centers for Disease Control and Prevention HIV disease classification, hemoglobin concentration, and serum beta 2-microglobulin) in proportional hazards models, mortality for all NP abnormal subjects remained elevated (RR, 1.8; 95% CI, 1.2-2.8; P < .01). The elevation in mortality risk for subjects with minor cognitive motor disorder was statistically significant (RR, 2.2; 95% CI, 1.2-3.8; P < .01); for NP impaired subjects it was marginally significant (RR, 1.6; 95% CI, 1.0-2.8; P = .06). CONCLUSIONS: The HIV-infected individuals with NP impairment had a higher risk of dying than those without impairment. This was particularly true for those meeting syndromic diagnostic criteria.

Adult↗
PubMed1997

NF1 mutation analysis using a combined heteroduplex/SSCP approach.

Neurofibromatosis type 1 (NF1) is a common autosomal dominant disorder characterized predominantly by neurofibromas, café-au-lait spots, and Lisch nodules. The disease is caused by disruptive mutations of the large NF1 gene, with half of cases caused by new mutation. Less than 100 constitutional mutations have thus far been published, ranging from very large deletions to point mutations. We have pursued NF1 mutation analysis by heteroduplex analysis (HDA) and single-strand conformational polymorphism analysis (SSCP) of individual exons. We streamlined these techniques to eliminate the use of radioactivity, to apply both methods to the same PCR product, and to multiplex samples in gels. Applied simultaneously to a set of 67 unrelated NF1 patients, HDA and SSCP have thus far identified 26 mutations and/or variants in 45 of the 59 exons tested. Disease-causing mutations were found in 19% (13/67) of cases studied. Both techniques detected a variety of mutations including splice mutations, insertions, deletions, and point changes, with some overlap in the ability of each method to detect variants.

Base Sequence↗
PubMed1997

Cerebrospinal fluid human immunodeficiency virus type 1 RNA levels are elevated in neurocognitively impaired individuals with acquired immunodeficiency syndrome. HIV Neurobehavioral Research Center Group.

To determine whether cerebrospinal fluid (CSF) viral burden measurements can assist in the evaluation of human immunodeficiency virus (HIV)-associated neurocognitive disorders, we quantified HIV type 1 (HIV-1) RNA in CSF. Because previous findings suggested that disease stage, lymphocytic pleocytosis, and HIV-1 RNA levels in plasma may influence CSF viral burden, these variables were examined as potential modifying factors. HIV-1 RNA levels were quantified by using a reverse transcriptase-polymerase chain reaction assay. Performance on a comprehensive neuropsychological (NP) battery was noted in 97 prospectively enrolled, HIV-infected subjects. Among subjects with acquired immunodeficiency syndrome (AIDS) (<200 CD4+ lymphocytes), NP impairment was associated with significantly higher CSF RNA levels (3.1 vs 1.8 log10 copies/ml; p = 0.02); most impaired subjects met criteria for HIV-associated dementia or minor cognitive-motor disorder. In subjects without AIDS, CSF RNA and NP impairment were unrelated. Before AIDS, CSF RNA was strongly correlated to plasma RNA and to pleocytosis, but in AIDS, CSF and plasma RNA were independent. In conclusion, we found elevated CSF HIV-1 RNA levels in NP impaired subjects with AIDS. Before AIDS, systemic viral replication, possibly through CD4+ mononuclear cell trafficking, may govern virus levels in CSF, whereas in AIDS, CD4 cell depletion may unmask a correlation between increased productive central nervous system HIV infection and clinical neurocognitive disorders.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Cross-clade immune responses after immunization with a whole-killed gp120-depleted human immunodeficiency virus type-1 immunogen in incomplete Freund's adjuvant (HIV-1 immunogen, REMUNE) in human immunodeficiency virus type-1 seropositive subjects.

Lymphocyte proliferation responses to gp120-depleted HZ321 virus (clade A) antigen were compared to BAL human immunodeficiency virus (HIV) virus antigen (clade B) responses, clade E HIV virus antigen responses, and purified native p24 antigen responses in 15 human immunodeficiency virus type-1 (HIV-1) seropositive subjects immunized with a whole-killed inactivated gp120-depleted HIV-1 antigen in Incomplete Freund's adjuvant (HIV-1 immunogen, REMUNE). A significant increase in lymphocyte proliferation to HZ321 antigen was observed after immunization with the HIV-1 immunogen (p = 0.02). A strong association was demonstrated between the HIV-1 immunizing antigen, HZ321, and native p24 antigen responses (r = 0.80, p < 0.0001). Furthermore, a strong association in terms of proliferative responses was demonstrated between HZ321 virus (clade A) responses and BAL virus (clade B) (r = 0.95, p < 0.0001) and clade E virus antigen (r = 0.92, p < 0.0001). Proliferative responses to HIV antigens also correlated with baseline CD4 counts. Taken together, these results support the specificity of immune responses induced by REMUNE (HIV-1 immunogen). The development of cross-reactive immune responses between clades and to the more conserved epitopes of the virus have implications in the development of therapeutic and prophylactic HIV vaccines.

AIDS Vaccines↗