10 resultados para white spot syndrome virus

em DigitalCommons@The Texas Medical Center


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Mother to child transmission of human immunodeficiency virus (HIV) has decreased dramatically in the United States since the mid-1990s. Without antiretroviral therapy the risk of perinatal infection is as high as 25%; with treatment the risk drops to <1-2%. However, state surveillance data show a recent rise in the percentage of babies being born with HIV in Texas. No studies of perinatal HIV transmission in Texas have focused on the individual cases and identified what social/institutional barriers stood in the way of the index woman, her support system and her health providers in negotiating access to prenatal care and HIV treatment.^ The Texas Department of State Health Services identifies the babies born in Texas with HIV infection. This two year study will use mixed methods to identify barriers to the diagnosis and treatment of maternal HIV. In-depth interviews and chart reviews will be used to conduct the study. The abstracted medical record will give us demographic data and details of the timing of testing and treatment; interviews will provide information as to the individual and environmental factors that may have delayed testing and treatment. Little research has been done to assess the factors contributing to late prenatal HIV diagnosis and care in Texas and the interventions identified by mothers of affected babies that might overcome these obstacles.^ Conclusions from this study will guide the development of interventions to better educate the public, reduce structural barriers common to the underserved, and/or educate health care professionals. The study will also serve as a model for other states to undertake evaluation of their cases of perinatal infection. ^

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Cytotoxic T lymphocytes (CTLs) play an important role in the suppression of initial viremia after acute infection with the human immunodeficiency virus (HIV), the causative agent of acquired immune deficiency syndrome (AIDS). Most HIV-infected individuals attain a high titer of anti-HIV antibodies within weeks of infection; however this antibody-mediated immune response appears not to be protective. In addition, anti-HIV antibodies can be detrimental to the immune response to HIV through enhancement of infection and participating in autoimmune reactions as a result of HIV protein mimicry of self antigens. Thus induction and maintenance of a strong HIV-specific CTL immune response in the absence of anti-HIV antibodies has been proposed to be the most effective means of controlling of HIV infection. Immunization with synthetic peptides representing HIV-specific CTL epitopes provides a way to induce specific CTL responses, while avoiding stimulation of anti-HIV antibody. This dissertation examines the capacity of synthetic peptides from the V3 loop region of the gp120 envelope protein from several different strain of HIV-1 to induce HIV-specific, MHC-restricted CD8$\sp+$ CTL response in vivo in a mouse model. Seven synthetic peptides representative of sequences found throughout North America, Europe, and Central Africa have been shown to prime CTLs in vivo. In the case of the MN strain of HIV-1, a 13 amino acid sequence defining the epitope is most efficient for optimal induction of specific CTL, whereas eight to nine amino acid sequences that could define the epitope were not immunogenic. In addition, synthesis of peptides with specific amino acid substitutions that are important for either MHC binding or T cell receptor recognition resulted in peptides that exhibited increased immunogenicity and induced CTLs that displayed altered specificity. V3 loop peptides from HIV-1 MN, SC, and Z321 induced a CTL population that was broadly cross-reactive against strains of HIV-1 found throughout the world. This research confirms the potential efficacy of using synthetic peptides for in vivo immunization to induce HIV-specific CTL-mediated responses and provides a basis for further research into development of synthetic peptide-based vaccines. ^

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Primate immunodeficiency viruses, or lentiviruses (HIV-1, HIV-2, and SIV), and hepatitis delta virus (HDV) are RNA viruses characterized by rapid evolution. Infection by primate immunodeficiency viruses usually results in the development of acquired immunodeficiency syndrome (AIDS) in humans and AIDS-like illnesses in Asian macaques. Similarly, hepatitis delta virus infection causes hepatitis and liver cancer in humans. These viruses are heterogeneous within an infected patient and among individuals. Substitution rates in the virus genomes are high and vary in different lineages and among sites. Methods of phylogenetic analysis were applied to study the evolution of primate lentiviruses and the hepatitis delta virus. The following results have been obtained: (1) The substitution rate varies among sites of primate lentivirus genes according to the two parameter gamma distribution, with the shape parameter $\alpha$ being close to 1. (2) Primate immunodeficiency viruses fall into species-specific lineages. Therefore, viral transmissions across primate species are not as frequent as suggested by previous authors. (3) Primate lentiviruses have acquired or lost their pathogenicity several times in the course of evolution. (4) Evidence was provided for multiple infections of a North American patient by distinct HIV-1 strains of the B subtype. (5) Computer simulations indicate that the probability of committing an error in testing HIV transmission depends on the number of virus sequences and their length, the divergence times among sequences, and the model of nucleotide substitution. (6) For future investigations of HIV-1 transmissions, using longer virus sequences and avoiding the use of distant outgroups is recommended. (7) Hepatitis delta virus strains are usually related according to the geographic region of isolation. (8) Evolution of HDV is characterized by the rate of synonymous substitution being lower than the nonsynonymous substitution rate and the rate of evolution of the noncoding region. (9) There is a strong preference for G and C nucleotides at the third codon positions of the HDV coding region. ^

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Background. Increased incidence of cancer is documented in immunosuppressed transplant patients. Likewise, as survival increases for persons infected with the Human Immunodeficiency Virus (HIV), we expect their incidence of cancer to increase. The objective of this study was to examine the current gender specific spectrum of cancer in an HIV infected cohort (especially malignancies not currently associated with Acquired Immunodeficiency Syndrome (AIDS)) in relation to the general population.^ Methods. Cancer incidence data was collected for residents of Harris County, Texas who were diagnosed with a malignancy between 1975 and 1994. This data was linked to HIV/AIDS registry data to identify malignancies in an HIV infected cohort of 14,986 persons. A standardized incidence ratio (SIR) analysis was used to compare incidence of cancer in this cohort to that in the general population. Risk factors such as mode of HIV infection, age, race and gender, were evaluated for contribution to the development of cancer within the HIV cohort, using Cox regression techniques.^ Findings. Of those in the HIV infected cohort, 2289 persons (15%) were identified as having one or more malignancies. The linkage identified 29.5% of these malignancies (males 28.7% females 60.9%). HIV infected men and women had incidences of cancer that were 16.7 (16.1, 17.3) and 2.9 (2.3, 3.7) times that expected for the general population of Harris County, Texas, adjusting for age. Significant SIR's were observed for the AIDS-defining malignancies of Kaposi's sarcoma, non-Hodgkin's lymphoma, primary lymphoma of the brain and cancer of the cervix. Additionally, significant SIR's for non-melanotic skin cancer in males, 6.9 (4.8, 9.5) and colon cancer in females, 4.0 (1.1, 10.2) were detected. Among the HIV infected cohort, race/ethnicity of White (relative risk 2.4 with 95% confidence intervals 2.0, 2.8) or Spanish Surname, 2.2 (1.9, 2.7) and an infection route of male to male sex, with, 3.0 (1.9, 4.9) or without, 3.4 (2.1, 5.5) intravenous drug use, increased the risk of having a diagnosis of an incident cancer.^ Interpretation. There appears to be an increased risk of developing cancer if infected with the HIV. In addition to the malignancies routinely associated with HIV infection, there appears to be an increased risk of being diagnosed with non-melanotic skin cancer in males and colon cancer in females. ^

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Purpose. We performed a case-comparison study to describe the characteristics of LUS tumors and their association with risk factors for endometrial cancer. ^ Patients and Methods. From January 1996 through October 2007, 3,892 women were identified with a diagnosis of primary endometrial carcinoma or primary cervical adenocarcinoma. Pathology records from the 1,009 women who had a hysterectomy were reviewed. Subjects were included in the LUS group only if the tumor was clearly originating from the area between the lower corpus and upper cervix in the hysterectomy specimen. The LUS group was compared to all patients with endometrial corpus carcinoma who underwent hysterectomy at our institution in a 12-month period randomly selected from the study period. Risk factors for endometrial carcinoma such as body mass index (BMI) and Lynch Syndrome were assessed. Expression of estrogen receptor (ER), vimentin, carcinoembryonic antigen (CEA), p16, and human papilloma virus DNA (HPV DNA) was assessed; this panel is known to be effective in distinguishing adenocarcinomas of endometrial versus endocervical origin. Fisher's Exact, Chi-square, Mann-Whitney, and Student's t-tests were utilized for statistical analysis. ^ Results. Thirty-five of 1,009 women had endometrial carcinoma of the LUS (3.5%; 95% CI: 2–4%). Compared to patients with corpus tumors, LUS patients were younger (54.2 vs. 62.9 years, P = .001), had higher stage (P < .001), and more invasive tumors (P = .001). Preoperative diagnosis of the LUS tumors more frequently included the possibility of endocervical adenocarcinoma ( P < .001), leading to preoperative radiation therapy in 4 patients. Median BMI was similar in the LUS and corpus groups. Seventy-three percent of the available LUS tumors had a similar immunohistochemical expression pattern to conventional endometrioid adenocarcinoma. Because of the young median age for the LUS group, we performed immunohistochemistry for Lynch syndrome-associated DNA mismatch repair proteins MLH1, MSH2, MSH6, and PMS2. Microsatellite instability testing (MSI) and MLH1 promoter hypermethylation were performed when indicated. Thirty-six percent of the LUS tumors were MSI-high. Ten of thirty-five (29%) women with LUS tumors were either confirmed to have Lynch Syndrome or were strongly suspected to have Lynch Syndrome based on tissue-based molecular assays (95% CI, 16 to 45%). ^ Conclusions. Endometrial carcinoma arising in the LUS is a clinical and pathologic entity which can be diagnostically confused with cervical adenocarcinoma. In general, LUS tumors can be correctly identified as being endometrial carcinoma using the immunohistochemical panel noted above. The prevalence of Lynch Syndrome in patients with LUS tumors is much greater than that of the general endometrial cancer population (1.8%) or in endometrial cancer patients younger than 50 years of age (8–9%). Based on our results, the possibility of Lynch Syndrome should be considered in women with LUS tumors. ^

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Little is known about epidemiological markers that are associated with survival of patients with myelodysplastic syndromes (MDS). We conducted a secondary case-based analysis of 465 de novo MDS patients from the University of Texas MD Anderson Cancer Center (UTMDACC). We investigated the association between demographic as well as occupational exposure markers and survival while incorporating known clinical markers of prognosis. In our patient population, 60.6% were men and the majority were white (93.1%). The distribution of MDS subtypes by the French–American–British (FAB) classification was 81 (19%) refractory anemia (RA), 46 (9.9%) refractory anemia with ringed sideroblasts (RARS), 57 (12.3%) chronic myelomonocytic leukemia (CMML), 173 (37.2%) RA with excess blasts (RAEB), and 86 (18.5%) RAEB in transformation (RAEBT). We found that those older at diagnosis (> 60 years of age) (HR = 1.68, CI = 1.26-2.25) were at a higher risk of dying compared to younger patients. Similarly, high pack years of smoking (>= 30 pack years of smoking) (HR = 1.34, CI = 1.02-1.74), and agricultural chemical exposure (HR = 1.61, CI = 1.05-2.46) were significantly associated with overall lower survival when compared to patients with none or medium exposures. Among clinical markers, greater than 5% bone marrow blasts (HR = 1.81 CI = 1.27-2.56), poor cytogenetics (HR = 3.20, CI = 2.37-4.33)), and platelet cytopenias (<100000/ul) (HR = 1.46, CI = 1.11-1.92) were also significantly associated with overall MDS survival.^ The identification of epidemiological markers could help physicians stratify patients and customize treatment strategies to improve the outcome of MDS based on patient lifestyle information such as smoking exposure and agrochemical exposure. We hope that this study highlights the impact of these exposures in MDS prognosis.^

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We conducted a nested case-control study to determine the significant risk factors for developing encephalitis from West Nile virus (WNV) infection. The purpose of this research project was to expand the previously published Houston study of 2002–2004 patients to include data on Houston patients from four additional years (2005–2008) to determine if there were any differences in risk factors shown to be associated with developing the more severe outcomes of WNV infection, encephalitis and death, by having this larger sample size. A re-analysis of the risk factors for encephalitis and death was conducted on all of the patients from 2002–2008 and was the focus of this proposed research. This analysis allowed for the determination to be made that there are differences in the outcome in the risk factors for encephalitis and death with an increased sample size. Retrospective medical chart reviews were completed for the 265 confirmed WNV hospitalized patients; 153 patients had encephalitis (WNE), 112 had either viral syndrome with fever (WNF) or meningitis (WNM); a total of 22 patients died. Univariate logistic regression analyses on demographic, comorbidities, and social risk factors was conducted in a similar manner as in the previously conducted study to determine the risk factors for developing encephalitis from WNV. A multivariate model was developed by using model building strategies for the multivariate logistic regression analysis. The hypothesis of this study was that there would be additional risk factors shown to be significant with the increase in sample size of the dataset. This analysis with a greater sample size and increased power supports the hypothesis in that there were additional risk factors shown to be statistically associated with the more severe outcomes of WNV infection (WNE or death). Based on univariate logistic regression results, these data showed that even though age of 20–44 years was statistically significant as a protecting effect for developing WNE in the original study, the expanded sample lacked significance. This study showed a significant WNE risk factor to be chronic alcohol abuse, when it was not significant in the original analysis. Other WNE risk factors identified in this analysis that showed to be significant but were not significant in the original analysis were cancer not in remission > 5 years, history of stroke, and chronic renal disease. When comparing the two analyses with death as an outcome, two risk factors that were shown to be significant in the original analysis but not in the expanded dataset analysis were diabetes mellitus and immunosuppression. Three risk factors shown to be significant in this expanded analysis but were not significant in the original study were illicit drug use, heroin or opiate use, and injection drug use. However, with the multiple logistic regression models, the same independent risk factors for developing encephalitis of age and history of hypertension including drug induced hypertension were consistent in both studies.^

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Li-Fraumeni syndrome (LFS) is characterized by a variety of neoplasms occurring at a young age with an apparent autosomal dominant transmission. Individuals in pedigrees with LFS have high incidence of second malignancies. Recently LFS has been found to be associated with germline mutations of a tumor-suppressor gene, p53. Because LFS is rare and indeed not a clear-cut disease, it is not known whether all cases of LFS are attributable to p53 germline mutations and how p53 plays in cancer occurrence in such cancer syndrome families. In the present study, DNAs from constitutive cells of two-hundred and thirty-three family members from ten extended pedigrees were screened for p53 mutations. Six out of the ten LFS families had germline mutations at the p53 locus, including point and deletion mutations. In these six families, 55 out of 146 members were carriers of p53 mutations. Except one, all mutations occurred in exons 5 to 8 (i.e., the "hot spot" region) of the p53 gene. The age-specific penetrance of cancer was estimated after the genotype for each family member at risk was determined. The penetrance was 0.15, 0.29, 0.35, 0.77, and 0.91 by 20, 30, 40, 50 and 60 year-old, respectively, in male carriers; 0.19, 0.44, 0.76, and 0.90 by 20, 30, 40, and 50 year-old, respectively, in female carriers. These results indicated that one cannot escape from tumorigenesis if one inherits a p53 mutant allele; at least ninety percent of p53 carriers will develop cancer by the age of 60. To evaluate the possible bias due to the unexamined blood-relatives in LFS families, I performed a simulation analysis in which a p53 genotype was assigned to each unexamined person based on his cancer status and liability to cancer. The results showed that the penetrance estimates were not biased by the unexamined relatives. I also determined the sex, site, and age-specific penetrance of breast cancer in female carriers and lung cancer in male carriers. The penetrance of breast cancer in female carriers was 0.81 by age 45; the penetrance of lung cancer in male carriers was 0.78 by age 60, indicating that p53 play a key role for tumorigenesis in common cancers. ^

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The study focused on the relationship between antisocial personality syndrome in boys ages 8-15 and parental alcohol/drug dependency. The population studied was case records of 101 boys coming to a private psychiatrist from 1966 through 1979. The boys were predominantly white and from middle to upper income families.^ A boy was determined to have antisocial personality syndrome if he exhibited antisocial behaviors in four or five major categories, did not exhibit a brain syndrome, and did not exhibit a thought disorder. The five major behavior categories were: (1) self-control (i.e., temper tantrums or hyperactivity), (2) behavior at home (i.e., disobedience or lying), (3) behavior at school (i.e., truancy or cheating), (4) behavior toward peers (i.e., bullying, fighting, or tattling), and (5) behavior against property (i.e., destructiveness or stealing). A boy was determined to be a control if he exhibited antisocial behaviors in two or less behavior categories.^ A parent was determined to have alcohol/drug dependency if s/he exhibited a score above the established threshold (1) for the MacAndrew Alcoholism Scale (28 or above), and (2) for the Holmes Alcoholism Scale (35 or above) which are used with the MMPI. A parent was classified not alcohol/drug dependent if s/he had scores below set thresholds (22 on the MacAndrew Alcoholism Scale and 28 on the Holmes Alcoholism Scale).^ For the final sample (N = 10), there was no reason to believe a relationship exists between antisocial personality syndrome in boys ages 8-15 and parental alcohol/drug dependency (Fisher's Exact Test {FET} P = 1.0). The small sample size primarily occurred as a result of 88.12% of the parents being classified in a questionable category in terms of alcohol/drug dependency.^ The sample was suggestive of a relationship between the fathers' Psychopathic Deviate (Pd) Scale scores as a measure of antisocial tendencies and the boy having antisocial personality syndrome (N = 75; P = .12). There was no evidence of such a relationship for mothers (N = 75; P = .97). ^

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For adolescents, unprotected sexual intercourse is the primary cause of sexually transmitted disease (STD), including Human Immunodeficiency Virus (HIV) infection (virus which causes Acquired Immunodeficiency Syndrome (AIDS)), and pregnancy. Although many studies on adolescent sexual behavior have addressed racial/ethnic differences, few studies have examined the relation between race/ethnicity while controlling for other sociocultural and psychosocial variables. The purpose of this study is to examine the relationship between racial/ethnic categories and selected sociocultural and psychosocial variables, with reported adolescent sexual risk-taking and preventive behavior.^ A self-administered questionnaire was used to collect information from 3132 students in a Texas school district (Section 3.5.2). The instrument contained approximately 100 questions on demographic characteristics, sexual behavior, and psychosocial determinants of sexual behavior. Based on the findings of this study, the following major conclusions are made: (1) There are differences in reported sexual risk-taking and preventive behavior among Black, Hispanic and White adolescents in this study. The stratified analysis by gender further suggests significant gender differences in reported sexual behavior among the three racial/ethnic groups. (2) Gender, living arrangement, academic grades, and language spoken at home modified the association between reported sexual risk-taking and preventive behavior and race/ethnicity in this study. This suggests that these sociocultural variables should be considered in future research and practice involving multicultural populations. (3) There are differences in selected psychosocial determinants among the three racial/ethnic groups and between males and females. These differences were consistent with the reported sexual risk-taking and preventive behaviors among race/ethnicity and gender for adolescents in this study. The findings support the consideration of psychosocial determinants in research and interventions addressing adolescent sexual behavior among different racial/ethnic groups.^ Based on the results of this study, two recommendations for practice are made. First, health professionals developing interventions for adolescents from different cultural backgrounds and gender need to be familiar with the specific sociocultural and psychosocial factors which will reduce risky sexual behavior, and promote protective behavior. Second, the need for immediate, realistic, and continuous HIV/STD and pregnancy prevention programs for children and adolescents should be considered. ^