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S Dube

Publications and source records attributed to S Dube.

At least 37 records · Page 2Linked to original sources
PubMed1998

Expansion of clonotypic T-cell populations in the peripheral blood of asymptomatic Gran Chaco Amerindians infected with HTLV-IIB.

Peripheral blood mononuclear cells from asymptomatic HTLV-II-infected and uninfected Gran Chaco Amerindians were analyzed using polymerase chain reaction (PCR) for expansions of T-cell receptor (TCR) V-beta gene clonotypes. Analyses were performed using primer pairs designed to identify expanded T-cell familial clonotypes based on their unique TCR beta gene rearrangements. Of the 30 HTLV-IIB-positive samples tested, five showed evidence of V-beta clonotypic T-cell expansion. Of the five expansions, two were monoclonotypic and the remaining three were oligoclonotypic. In comparison, 30 HTLV-II-negative Amerindians showed no evidence of clonotypic T-cell expansion. Amplified DNA from one of the monoclonotypic samples was subsequently cloned and sequenced and was found to have uniform variable/ diversity/joining sequences confirming its unique monoclonal T-cell expansion. This method of detecting clonal TCR beta gene rearrangements has the advantage over traditional Southern blot techniques of being more sensitive and specific even with suboptimal specimens. The prognostic significance of clonotypic T-cell expansion in a group such as the HTLV-II-infected Gran Chaco Amerindians remains to be determined.

Argentina↗
PubMed1998

Endemic infection with HTLV-IIB in Venezuelan Indians: molecular characterization.

The peripheral blood of 41 Yaruro and Guahibo Indians from Venezuela was examined for HTLV antibodies and DNA. Twenty-five samples (61%) were found to be infected with HTLV-IIB. The sensitivities of the serologic and DNA polymerase chain reaction (PCR) analyses were 80% and 96%, respectively. Epidemiologic studies supported both sexual and perinatal transmission of the virus. Sequence analyses of the HTLV-IIB strains from these Indians indicate that they are unique relative to HTLV-II detected in other groups of humans. HTLV-IIB-G2 isolated from a Guahibo Indian is the most divergent HTLV-IIB strain relative to the prototype HTLV-II NRA.

Adolescent↗
PubMed1998

Detection of human herpesvirus 8 DNA sequences in tissues and bodily fluids.

Human herpesvirus 8 (HHV-8) has been proposed as a sexually transmitted etiologic agent of Kaposi's sarcoma (KS). In this study, by use of a sensitive polymerase chain reaction assay, HHV-8 DNA was detected in the skin lesions (92%), normal skin (23%), peripheral blood mononuclear cells (PBMC) (46%), plasma (7%), saliva (37%), and semen (12%) but not stool samples from KS patients. The average number of HHV-8 copies per microgram of positive target DNA was 64, 000, 9000, 40, 33,000, and 300 for skin, PBMC, plasma, saliva, and semen samples, respectively. Only 1 non-KS donor sample, of saliva, was positive for HHV-8. Sequencing showed 5% divergence among HHV-8 strains. The data suggest that saliva may be more important than semen or stool in the sexual transmission of HHV-8. The relatively high prevalence of HHV-8 in PBMC raises the question as to why there is no evidence for bloodborne virus transmission.

DNA, Viral↗
PubMed1997

Differential expression of a novel isoform of alpha-tropomyosin in cardiac and skeletal muscle of the Mexican axolotl (Ambystoma mexicanum).

Alternative mRNA splicing is a fundamental process in eukaryotes that contributes to tissue-specific and developmentally regulated patterns of tropomyosin (TM) gene expression. Northern blot analyses suggest the presence of multiple transcripts of tropomyosin in skeletal and cardiac muscle of adult Mexican axolotls. We have cloned and sequenced two tropomyosin cDNAs designated ATmC-1 and ATmC-2 from axolotl heart tissue and one TM cDNA from skeletal muscle, designated ATmS-1. Nucleotide sequence analyses suggest that ATmC-1 and ATmC-2 are the products of the same alpha-TM gene produced via alternate splicing, whereas ATmC-1 and ATmS-1 are the identical isoforms generated from the alpha-gene. RT-PCR analysis using isoform-specific primer pairs and detector oligonucleotides suggests that ATmC-2 is expressed predominantly in adult axolotl hearts. ATmC-2 is a novel isoform, which unlike ATmC-1 and other known striated muscle isoforms expresses exon 2a instead of exon 2b.

Ambystoma↗
PubMed1997

Comparative performances of enzyme-linked immunosorbent, western blot, and polymerase chain reaction assays for human T-lymphotropic virus type II infection that is endemic among Indians of the Gran Chaco region of South America.

BACKGROUND: Human T-cell lymphoma/leukemia viruses types I and II (HTLV-I and HTLV-II) are related exogenous human retroviruses. The former is definitely pathogenic while disease association with the latter is unclear. There are two subtypes of HTLV-II, A and B. Currently, enzyme-linked immunosorbent assays (ELISAs) based on HTLV-I antigens are used to screen for the presence of HTLV-I and -II antibodies. Confirmation and subtyping are accomplished by Western blot (WB) or ELISAs based on HTLV-I whole viral antigens and/or HTLV-I and HTLV-IIA peptides. The sensitivity and specificity of these serologic assays were compared to those of HTLV-I and-II-specific polymerase chain reaction (PCR) assays in tests on samples from Indians from South America in whom the HTLV-IIB subtype is endemic. STUDY DESIGN AND METHODS: Sera from 246 Gran Chaco Indians were evaluated for HTLV antibodies with the use of four ELISAs (Retrotek HTLV-I; Cambridge Biotech rgp21 enhanced HTLV-I/II; Vironostika HTLV-I/II; and Select HTLV-I/II), and a WB assay. Peripheral blood leukocyte DNA from each Indian was analyzed for HTLV-I or HTLV-II pol DNA via PCR. Fifteen of the PCR-positive samples were further subtyped via cloning and sequencing and/or oligomer restriction. RESULTS: Ninety-seven samples (39%) were positive for HTLV-II by serologic and/or PCR assays. All 15 positive DNA samples that were further analyzed were of the HTLV-IIB subtype and were clustered as a highly conserved phylogenetic group. Comparative analyses indicate that the sensitivity and specificity of the various assays were: PCR, 97 and 100 percent; Retrotek, 70 and 91 percent; Cambridge Biotech, 74 and 96 percent; Vironostika, 73 and 99 percent; Select 72 and 98 percent; and WB, 70 and 100 percent. CONCLUSION: The sensitivities of the tested HTLV serologic assays were comparable. However, the specificity of the Retrotek ELISA was significantly lower than that of the others. When positive, the subtyping assays were very specific. However, PCR assays would seem preferable or to be a necessary adjunct for the sensitive detection of HTLV-IIB infection.

Adolescent↗
PubMed1997

Degenerate and specific PCR assays for the detection of bovine leukaemia virus and primate T cell leukaemia/lymphoma virus pol DNA and RNA: phylogenetic comparisons of amplified sequences from cattle and primates from around the world.

Degenerate and specific PCR assays were developed for bovine leukaemia virus (BLV) and/or primate T cell leukaemia/lymphoma viruses (PTLV). The degenerate assays detected all major variants of the BLV/PTLV genus at a sensitivity of 10-100 copies of input DNA; the specific systems detected 1-10 copies of input target. Sensitivity was 100% in specific DNA-PCR assays done on peripheral blood from seropositive BLV-infected cattle and HTLV-I- or HTLV-II-infected humans, and 62% in RNA/DNA-PCR assays on sera from BLV seropositive cattle. The pol fragments from 21 different BLV strains, isolated from cattle in North and Central America, were cloned and sequenced, and compared to other published BLV and PTLV pol sequences. BLV and PTLV sequences differed by 42%. Sequence divergence was up to 6% among the BLV strains, and up to 36% among the PTLV strains (with PTLV-I and PTLV-II differing among themselves by 15% and 8%, respectively). Some cows were infected with several BLV strains. Among retroviruses, BLV and PTLV sequences formed a distinct clade. The data support the interpretation that BLV and PTLV evolved from a common ancestor many millennia ago, and some considerable time before the PTLV-I and PTLV-II strains diverged from each other. The dissemination of the BLV strains studied probably resulted from the export of European cattle throughout the world over the last 500 years. The relatively similar mutation rates of BLV and PTLV, after their various points of divergence, suggest that there could be a much wider genetic range of BLV than has currently been defined.

Amino Acid Sequence↗
PubMed1997

Cerebral malaria.

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Antimalarials↗
PubMed1996

Endemic infection with human T cell leukemia/lymphoma virus type IIB in Argentinean and Paraguayan Indians: epidemiology and molecular characterization.

Human T cell leukemia/lymphoma virus (HTLV-II) type II infection was detected by polymerase chain reaction or serologic analyses (or both) in 22% of 697 Indians of six different ethnic back-grounds inhabiting the Argentinean and Paraguayan Gran Chaco. None was infected with HTLV-I. The prevalence of HTLV-II increased with age (14% in those < 13 years and 23% in those > or = 13 years). HTLV-II infection was found in all 20 Gran Chaco communities studied, but marked differences (44%-4%) in the rate of infection were observed even in communities separated by only a few miles. These variations correlated closely with ethnicity. In the high-incidence communities, infection clustered within families, with evidence for both sexual and perinatal transmission, primarily via breast-feeding. By contrast, only 2% of 94 Mapuche Indians from southern Argentina were positive for HTLV-II. Analyses of pol and long terminal repeat sequences from 15 Gran Chaco HTLV-II strains indicated that they constitute a highly conserved branch of the HTLV-IIB substrain.

Adolescent↗
PubMed1995

A rapid and sensitive method of identification of HTLV-II subtypes.

There are 2 subtypes of human T-cell lymphoma/leukemia virus type II (HTLV-II), A and B. HTLV-II is increasingly associated with rare forms of lymphocytic neoplasia and a neurodegenerative disorder, characterized by hyperspasticity and ataxia. We have used PCR to amplify, clone and sequence 140 bp of the pol gene from many isolates of HTLV-IIA and HTLV-IIB from around the world. Analysis of these and other published sequence established that all HTLV-IIA sequences contained a unique Hinf I site and all HTLV-IIB sequences a unique Mse I site. A rapid and specific oligomer restriction (OR) assay was developed utilizing the primer pair SK110/SK111 and subsequent digestion with these enzymes. Concordance between sequenced and OR-based subtyping of DNA amplified by PCR was absolute among 22 HTLV-II isolates tested. Further OR or sequence analyses on an additional 30 other isolates indicated that the majority of North American non-indian HTLV-II isolates were subtype A, while all Paleo-Amerindian samples, including those from the Seminole of Florida; the Guaymi from Panama; and the Toba, Chorote, Wichi, and Chulupe of Argentina, belonged to subtype B. The SK110/SK111 PCR-OR format should facilitate molecular epidemiology studies of HTLV-II infection and allow for subtype stratification in assessing the sensitivity and specificity of HTLV detection formats and HTLV-II disease association.

Argentina↗
PubMed1995

Child sexual abuse in Matabeleland, Zimbabwe.

The extent, nature, causes and consequences of child sexual abuse in Matabeleland. Zimbabwe, are explored by an intersectoral working group consisting of health, legal and AIDS prevention workers who were struck in the course of their work by the regularity with which they saw sexually abused children infected with HIV and STDs. Methods used in this study are record review, focus group discussions, structured and in-depth interviews. Child sexual abuse cases form between 40-60% of the rape cases brought to the attention of hospitals, police and court and many more are believed to remain unreported. Half of the sexual abuse in children is detected through STDs and some have HIV. The majority of offenders are mature men known to the child. Factors influencing child sexual abuse are male dominance in society, men's professed inability to control sexual desire, and magic beliefs. Victims are traumatized by the abuse itself as well as by subsequent problems in family, health and in court. Since child sexual abuse may endanger the life and well-being of the child, it is a serious problem that requires urgent action.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Regulation of coronary diameter by myogenic mechanisms in arterial microvessels greater than 100 microns in diameter.

We performed the present study to determine the quantitative significance of transient and steady-state myogenic responses in isolated coronary resistance vessels greater than 100 microns in diameter. Small coronary arteries were isolated from freshly excised porcine hearts (n = 14) and were studied under static conditions in a superfused vessel chamber that allowed internal diameter to be assessed continuously using video microscopic techniques. At a mean distending pressure of 50 mmHg, the passive diameter of resistance arteries following sodium nitroprusside averaged 181 +/- 10 (SE) microns. Upon heating, vessels developed spontaneous tone and constricted to 72 +/- 3% of their maximum diameter. After a 30-mmHg step change in coronary pressure from 50 to 80 mmHg, there was an initial dilation from 131 +/- 9 to 149 +/- 11 microns, followed by myogenic constriction that returned diameter to the initial value over a period of several minutes (134 +/- 10 microns, P = NS). Directionally opposite peak transients were observed during reductions in pressure. Steady-state diameter remained relatively constant over a pressure range from 100 to 20 mmHg. Although these data demonstrate that myogenic responses are present in resistance arteries that are greater than 100 microns in diameter, their contribution to steady-state coronary resistance changes as pressure is varied is small. This suggests that additional mechanisms contribute to the phenomenon of coronary autoregulation in this class of resistance vessel.

Animals↗
PubMed1995

Monoamine oxidase inhibitor dietary restrictions: what are we asking patients to give up?

BACKGROUND: Though the list of possible indications for monoamine oxidase inhibitors (MAOIs) continues to expand, many psychiatrists remain hesitant about prescribing MAOIs, citing concerns about dietary prohibitions and hypertensive reactions. Data about psychiatric patients' frequency of consumption of foods, beverages, and medications prohibited during MAOI use are lacking. METHOD: We conducted a survey of 139 psychiatric patients admitted to either an inpatient unit specializing in the treatment of mood disorders or an outpatient anxiety disorders clinic specializing in the treatment of social phobia. At inclusion, patients were not being treated with MAOIs, although they might have received such treatment afterward. All patients completed a self-report questionnaire created for this study to ascertain their consumption of food, beverage, and medication items frequently found on MAOI diet lists. Demographic and diagnostic information was also recorded. RESULTS: The most frequently used high-risk items were the hard cheeses. Ninety percent of patients reported daily or weekly consumption of some food containing cheese, while less than 1% of patients reported never eating hard cheese. Yeast products, dry sausage, corned beef, broad beans, sauerkraut, and beer were used at least monthly by more than 50% of patients. Of the intermediate-risk foods, chocolate was the most frequently consumed, with almost 30% of the patients eating some chocolate daily. Over 40% of patients reported using over-the-counter cold preparations on a monthly basis. CONCLUSION: A wide variety of tyramine-containing foods and contraindicated medications were commonly used by our patients prior to evaluation for possible MAOI pharmacotherapy. The number and diversity of frequently consumed items do not support recommendations to reduce the breadth of restrictions in MAOI diets. Individually targeted dietary assessment and education are recommended to reduce the risks of prescribing MAOIs.

Adult↗
PubMed1994

Seroepidemiologic, molecular, and phylogenetic analyses of simian T-cell leukemia viruses (STLV-I) from various naturally infected monkey species from central and western Africa.

A study of simian T-cell lymphoma/leukemia virus infection, conducted on 747 nonhuman primates belonging to 14 different species in Central and Western Africa, indicated that 4 species (Cercopithecus aethiops, Erythrocebus patas, Papio doguera, and Cercopithecus mona pogonias) had a high prevalence of seropositivity to simian T-cell lymphoma/leukemia virus type I (STLV-I). The other nonhuman primate species, however, had negative or low levels of anti-HTLV-I antibodies. STLV-I pol and env DNA was detected in 12 of 12 different animals among the seropositive species. However, STLV-I pX DNA could be detected in only 10 of 12 animals. Comparative phylogenetic analyses based on 140 bp sequence of the pol gene indicate that these STLV-I isolates were 0-9% divergent from each other and were 3.5-7% divergent from the prototype related human retrovirus HTLV-I (ATK). The West African STLV-I isolates formed a unique phylogenetic cluster as did most of the Central African STLV-I isolates, save for STLV-I (Tan 90). The phylogenetic data indicate that cross species transmission of HTLV-I and STLV-I continued to occur long after their ancestral strain separated from the progenitor to HTLV-II. Comparative amino acid analyses indicated that there was marked conservation of the TAX protein regardless of host species, while the pol and REX proteins exhibited increasing levels of diversity.

Africa, Central↗
PubMed1994

Serological and nucleic acid analyses for HIV and HTLV infection on archival human plasma samples from Zaire.

In order to better understand the genomic diversity and molecular phylogeny of the human retroviruses, the plasmas from 250 Zairean patients collected in 1969 were tested for antibodies to human T-cell lymphoma and human immunodeficiency viruses (HTLV or HIV) using ELISA and confirmatory Western blots and for viral nucleic acids by reverse transcriptase-directed PCR (RT-PCR). Interestingly, none of the patients was confirmed positive for HIV, even though this region is now endemic for HIV-1. However, 74 (30%) and 3 (1%) of the samples were positive for antibodies to HTLV-I and II, respectively. Forty-four of 74 (59%) Western blot-positive Zairean samples were RT-PCR positive for HTLV-I, while 1 of 3 (33%) of HTLV-II-seropositive samples was RT-PCR positive. On the contrary, none of the Western blot-negative or indeterminate samples were RT-PCR positive for either HTLV-I or HTLV-II. We have cloned and sequenced 140 bp of the pol gene flanked by SK110/SK111 from 8 HTLV-I- and 1 HTLV-II-positive archival samples from Zaire. The HTLV-I isolates from Zaire cluster together as a phylogenetic group, diverging from the prototype Japanese HTLV-I (ATK) by a range of 1.4 to 3.6%. Their close homology to some African STLV-I isolates suggests relatively recent interspecies transmission. The Zairean HTLV-II isolate is closely grouped with the HTLV-II substrain of isolates found in Paleo-Amerindians of the New World, making it unlikely that it represents an endemic African strain.

Antibodies, Viral↗
PubMed1993

Sequence analysis of an immunogenic and neutralizing domain of the human T-cell lymphoma/leukemia virus type I gp46 surface membrane protein among various primate T-cell lymphoma/leukemia virus isolates including those from a patient with both HTLV-I-associated myelopathy and adult T-cell leukemia.

Human T-cell lymphoma/leukemia virus type I (HTLV-I) causes adult T-cell leukemia/lymphoma and HTLV-I-associated myelopathy. Specific regions within the outer envelope proteins of other retroviruses, e.g., human immunodeficiency virus type 1, are highly immunogenic and, because of the selective pressure of the host immune system, quite variable. Mutations in the external envelope protein gene of murine retroviruses and human immunodeficiency virus type 1 influence cellular tropism and disease pathogenesis. By contrast, no disease-specific viral mutations have been identified in HTLV-I-infected patients. However, all isolates studied thus far have originated from leukemic cell lines, peripheral blood mononuclear cells, or cerebrospinal fluid lymphocytes from patients with HTLV-I-associated myelopathy and adult T-cell leukemia/lymphoma and, therefore, may not truly reflect tissue-associated variation. The midregion of the HTLV-I gp46 external envelope glycoprotein (amino acids 190-209) induces an antibody response in 90% of infected individuals, and a hexapeptide in this region (amino acids 191-196) elicits antibodies in rabbits which inhibit syncytia formation and infection of target lymphocytes. Because of the above, we expected the neutralizing domain of the gp46 env gene of HTLV-I to possess disease or organ-associated mutations selected by the infected host's immune system. Hence, we amplified, cloned, and sequenced HTLV-I DNA directly from in vivo central nervous system, spleen, and kidney specimens, and a leukemic cell line from a patient (M. J.) with both HTLV-I-associated myelopathy and adult T-cell leukemia/lymphoma to discern the possibility of tissue- and/or disease-specific variants. In addition, we sequenced several HTLV-I isolates from different regions of the world, including Papua New Guinea, Bellona, and Liberia, and compared them to other previously published HTLV-I and related retroviral sequences. The 239-base pair sequence corresponding to amino acids 178 to 256 in gp46 displayed minor tissue-specific variation in clones derived from central nervous system tissues from patient M. J., but overall was highly conserved at both the DNA and amino acid levels. Variation was observed in this region among the other HTLV-I, simian T-cell lymphoma virus type I, and HTLV-II isolates in a pattern that was consistent with their known phylogenetic relationship. No consistent disease-related changes were observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1993

High rate of infection with the human T-cell leukemia retrovirus type II in four Indian populations of Argentina.

Sera from 215 non-drug-injecting Toba and Mataco-Mataguayo pure Indians belonging to four communities in northern Argentina were examined using assays that allow differentiation between reactivities due to type-specific antigens of the human T-cell leukemia/lymphoma virus (HTLV). Three of these populations have very little contact with non-Indian groups and reside in remote, isolated areas. HTLV-II type-specific seroreactivity was present in 24 (13.7%) of the 175 Indians older than 13 years of age and in none of the 40 who were of younger ages. None of the Indians had antibodies reacting with HTLV-I type-specific antigen. Seroreactivity was more prevalent and appeared at younger ages in females than in males. The majority of the HTLV-II-seropositive Indians belonged to the more isolated communities. The seroprevalences among the Tobas and Mataco-Mataguayo Indians were comparable. With the exception of a Toba who was positive in a test for Treponema pallidum, no serological evidence of sexually transmitted infections with this spirochete, hepatitis B virus, hepatitis C virus, and human immunodeficiency virus was found among the Indians tested. None of the 55 non-Indian people tested in the region showed HTLV-II type-specific seroreactivity. PCR analysis of DNA isolated from peripheral blood lymphocytes of seropositive Indians confirmed that the virus present in these populations is HTLV-II. Sequence analysis of PCR-amplified genomic segments showed that the virus belongs to the HTLV-II subtype which has been found to be endemic in other Paleo-American Indians.

Adolescent↗