Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002895 (sickle cell disease)
 11,747 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The spleen and lymph nodes are major sites of human immunodeficiency virus type 1 (HIV-1) replication, mutation, and genetic variation in vivo. If a major portion of the lymphatic tissue, such as the spleen, is removed or otherwise is unavailable for invasion by the HIV-1 virus, will the course of the infection be altered, resulting in a prolonged symptom-free interval or even increased survival? The spleen of most adults with sickle cell anemia (SS) is nonfunctional due to recurrent episodes of microinfarction. If autosplenectomized SS patients are exposed to HIV-1, they may be ideal candidates to examine the question of whether absence of splenic function at the time of infection will positively alter the course of HIV-1-related disease. All SS patients with a diagnosis of HIV-1 infection at five university sickle cell centers were included in the patient cohort. Patients in active treatment or in follow-up (group A, n = 11) underwent a series of quantitative viral studies to determine their HIV-1 viral burden. The studies included the branched-DNA signal amplification assay, quantitative DNA-polymerase chain reaction (PCR), quantitative reverse transcription (RT)-initiated-PCR, and in situ PCR. All patients who died of the complications of the acquired immunodeficiency syndrome (AIDS) or of SS, lost to follow-up, or were otherwise unavailable for study (Group B: n = 7) were included in the total patient group. None of the patients in group B underwent quantitative viral studies. In addition, a control population (group C, n = 36) of HIV-1-infected African Americans without SS, of similar age and gender to the SS patients, were compared with the study population for outcomes. In eight of 11 active patients (group A), the CD4+ T-lymphocyte counts were normal and viral burdens were low for an average of 10.25 years following diagnosis. These eight patients all from group A were the only long-term nonprogressors (44%) among a total of 18 SS patients (groups A and B). In group C (control), only five patients of 36 were long-term nonprogressors (13.9%). Five patients (28%) of the total SS group (groups A and B) succumbed to AIDS. One of the five was from Group A. The evaluation of a limited number of adult individuals suggests that a significant proportion of HIV-1-seropositive SS patients (44%) may be asymptomatic long-term nonprogressors. In these patients, the CD4+ T-lymphocyte counts remained high and their viral burdens were remarkably lower than in non-SS HIV-1-seropositive individuals. Whereas this study does not prove an "autosplenectomy" hypothesis, it suggests that in patients with both SS and HIV-1 infection, the retroviral disease may be ameliorated by host factors of which absence of splenic function prior to HIV-1 infection may be one.
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PMID:Viral burden and disease progression in HIV-1-infected patients with sickle cell anemia. 979 57

This document establishes Department of Veterans Affairs (VA) regulations to implement specific provisions of the Veterans Omnibus Health Care Act of 1976 and the Veterans' Benefits and Services Act of 1988 concerning the confidentiality of certain medical records. These regulations protect the confidentiality of VA records pertaining to drug abuse, alcoholism or alcohol abuse, infection with the human immunodeficiency virus (HIV), and sickle cell anemia.
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PMID:Confidentiality of certain medical records--VA. Final rule. 1017 36

We identified maternal demographic, behavioral, and medical history factors that predict bacteriuria (that is, symptomatic and asymptomatic urinary tract infection) at prenatal care initiation. We applied logistic regression modeling to data from all prenatal care recipients who delivered during 1990-1993 and resided in selected North Carolina counties (N = 8037), omitting those with diabetes mellitus, human immunodeficiency virus, or structural urologic abnormalities. The two strongest predictors of bacteriuria at prenatal care initiation were an antepartum urinary tract infection prior to prenatal care initiation (for whites, adjusted prevalence odds ratio (POR) = 2.5, 95% CI 0.6-9.8; for blacks, POR = 8.8, 95% CI 3.8-20.3) and a pre-pregnancy history of urinary tract infection (POR = 2.1, 95% CI 1.4-3.2). For white women only, education beyond high school and age > or =30 years were inversely associated (POR < or = 0.6). Sickle cell hemoglobin nearly doubled the prevalence odds for bacteriuria among African-Americans (POR = 1.9, 95% CI 1.0-3.5), whereas African-Americans with normal hemoglobin had reduced prevalence odds compared with whites (POR = 0.6, 95% CI 0.4-0.9). This study suggests predictors not considered before, including race controlling for sickle cell disease or trait and antepartum urinary tract infections prior to prenatal care.
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PMID:Predictors of urinary tract infection at the first prenatal visit. 1023 Aug 39

Pneumonia causes about three million deaths a year in young children, nearly all of which are in developing countries. Streptococcus pneumoniae (the pneumococcus) is the most important bacterial cause of pneumonia in young children and so is likely to be responsible for a high proportion of these deaths. The pneumococcus is also responsible for a substantial proportion of the 100,000-500,000 deaths that occur from meningitis in children each year. The incidence of invasive pneumococcal disease in children in the developing world is several times higher than in industrialized countries. This discrepancy may, in part, be due to socio-economic differences but genetic factors may also play a role. Children with sickle cell disease have a substantially increased risk of invasive pneumococcal infection and a search is being made for other possible genetic risk factors. Infection with human immunodeficiency virus (HIV) also predisposes to invasive pneumococcal disease and so the incidence of this disease in young children is expected to rise as increasing numbers of African and Asian children are born with a perinatally acquired HIV infection. Until recently, pneumococcal infections could be treated effectively with penicillin, a cheap and safe antibiotic. However, pneumococci that are resistant to penicillin are becoming prevalent in many countries, necessitating a change to more costly antibiotics which may be beyond the reach of the health services of poor, developing countries. The spread of antibiotic resistance has provided an added stimulus to the development of vaccines that might be able to prevent pneumococcal disease in infants. Recently developed polysaccharide-protein conjugate vaccines show promise and are now undergoing field trials. How deployment of these vaccines will influence the balance between invasive pneumococcal infections and asymptomatic nasopharyngeal carriage of pneumococci is uncertain.
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PMID:The epidemiology of pneumococcal infection in children in the developing world. 1036 3

The results of more than three decades of work indicate that zinc deficiency rapidly diminishes antibody- and cell-mediated responses in both humans and animals. The moderate deficiencies in zinc noted in sickle cell anemia, renal disease, chronic gastrointestinal disorders and acrodermatitis enteropathica; subjects with human immunodeficiency virus; children with diarrhea; and elderly persons can greatly alter host defense systems, leading to increases in opportunistic infections and mortality rates. Conversely, short periods of zinc supplementation substantially improve immune defense in individuals with these diseases. Mouse models demonstrate that 30 d of suboptimal intake of zinc can lead to 30-80% losses in defense capacity. Collectively, the data clearly demonstrate that immune integrity is tightly linked to zinc status. Lymphopenia and thymic atrophy, which were the early hallmarks of zinc deficiency, are now known to be due to high losses of precursor T and B cells in the bone marrow. This ultimately leads to lymphopenia or a failure to replenish the lymphocytic system. Glucocorticoid-mediated apoptosis induced by zinc deficiency causes down-regulation of lymphopoiesis. Indeed, zinc itself can modulate death processes in precursor lymphocytes. Finally, there is substantial evidence that zinc supplementation may well reduce the impact of many of the aforementioned diseases by preventing the dismantling of the immune system. The latter represents an important area for research.
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PMID:The dynamic link between the integrity of the immune system and zinc status. 1080 51

Hydroxyurea has been extensively used in medical practice, mainly for treating chronic myelogenous leukemia, sickle cell anemia, and other diseases. In light of its ability to inhibit DNA synthesis and to induce cell cycle arrest through inhibition of ribonucleotide reductase, the effects of hydroxyurea on replication of human immunodeficiency virus type 1 (HIV-1) have been investigated. In vitro hydroxyurea has been shown to block HIV-1 reverse transcription and/or replication in quiescent peripheral blood mononuclear cells (PBMC) and macrophages. Hydroxyurea was also found to be synergistic with the nucleoside reverse transcriptase inhibitor didanosine and to inhibit HIV-1 replication in activated PBMC; this inhibition may be due to a reduction in deoxynucleoside triphosphate pool sizes. Finally, hydroxyurea has been shown to sensitize didanosine-resistant mutants. Hydroxyurea may therefore be useful for limiting the spread of didanosine-resistant HIV-1 variants. The favorable toxicity profile of hydroxyurea and the lack of significant overlapping toxicities with some of the nucleoside reverse transcriptase inhibitors, as well as their distinct mechanisms of action, have provided further rationale for use of these agents in combination therapies.
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PMID:Rationale for the use of hydroxyurea as an anti-human immunodeficiency virus drug. 1086 Sep 5

Heptavalent pneumococcal conjugate vaccine (PCV7) is recommended for universal use in children 23 months and younger, to be given concurrently with other recommended childhood vaccines at 2, 4, 6, and 12 to 15 months of age. For children 7 to 23 months old who have not received previous doses of PCV7, administration of a reduced number of doses is recommended. Two doses of PCV7 are recommended for children 24 to 59 months old at high risk of invasive pneumococcal infection-including children with functional, anatomic, or congenital asplenia; infection with human immunodeficiency virus; and other predisposing conditions-who have not been immunized previously with PCV7. Recommendations have been made for use of 23-valent pneumococcal polysaccharide (23PS) vaccine in high-risk children to expand serotype coverage. High-risk children should be given vaccines at the earliest possible opportunity. Use of antibiotic prophylaxis in children younger than 5 years with functional or anatomic asplenia, including children with sickle cell disease, continues to be recommended. Children who have not experienced invasive pneumococcal infection and have received recommended pneumococcal immunizations may discontinue prophylaxis after 5 years of age. The safety and efficacy of PCV7 and 23PS in children 24 months or older at moderate or lower risk of invasive pneumococcal infection remain under investigation. Current US Food and Drug Administration indications are for administration of PCV7 only to children younger than 24 months. Data are insufficient to recommend routine administration of PCV7 for children at moderate risk of pneumococcal invasive infection, including all children 24 to 35 months old, children 36 to 59 months old who attend out-of-home care, and children 36 to 59 months old who are of Native American (American Indian and Alaska Native) or African American descent. However, all children 24 to 59 months old, regardless of whether they are at low or moderate risk, may benefit from the administration of pneumococcal immunizations. Therefore, a single dose of PCV7 or 23PS vaccine may be given to children 24 months or older. The 23PS is an acceptable alternative to PCV7, although an enhanced immune response and probable reduction of nasopharyngeal carriage favor the use of PCV7 whenever possible.
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PMID:American Academy of Pediatrics. Committee on Infectious Diseases. Policy statement: recommendations for the prevention of pneumococcal infections, including the use of pneumococcal conjugate vaccine (Prevnar), pneumococcal polysaccharide vaccine, and antibiotic prophylaxis. 1092 Jan 69

The cytotoxicity of hydroxyurea (HU), currently used to combat various cancers, sickle cell anemia and human immunodeficiency infection, was assessed by exposing decidualized and pregnant uteri of Sprague-Dawley rats to this drug. Consecutive daily doses of HU (500 mg/kg(-1)) for 4 days were injected subcutaneously during decidualization when proliferation of the deciduoma was biochemically analyzed on pseudopregnancy day 9, or injected intraperitoneally during pregnancy when uterine developmental processes were evaluated on gestation day 16. Hydroxyurea displayed prominent antiproliferative effects on decidual growth. These actions were comparable to significantly impaired (P<0.001) developmental responses (increases in post-implantation losses, in resorbed fetuses and in reduced fetal and placental weights) during pregnancy. The cellular components inhibited by HU were DNA, protein, nitric oxide synthase, a matrix metalloproteinase and decidual prolactin-related protein mRNA (P<0.05). Steroid-related endocrine events (serum progesterone concentrations, estrogen receptor and mRNA levels) were unaffected by HU, implying direct cellular action by the drug. Interestingly, endometrial alkaline phosphatase bioactivity was enhanced by HU (P<0.05). Subsequently, the reproductive toxicity of HU was apparently related to mitogenic and differentiation-induced endometrial cellular activities.
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PMID:Hydroxyurea inhibition of cellular and developmental activities in the decidualized and pregnant uteri of rats. 1113 71

Homozygous sickle cell disease (SCD) has a wide spectrum of clinical manifestations which varies from an almost asymptomatic condition to severe illness, despite the fact that all subjects with this disease have the same base change in their DNA. The source of this variation is partly environmental, but a large part of this variability can derive from the presence of genetic modulators which are not fully understood. It was postulated that some degree of immunodeficiency should be associated with this condition, but no deficiency, directly related to a given component of the immune system, was observed that could explain the high levels of recurrent infections presented by sickle cell disease patients. Reviewing data from the literature we suggest that the influence of the immune system in the variation of clinical manifestations presented by SCD patients is not related with any immunodeficiency but is rather the result of a chronic inflammatory condition.
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PMID:Sickle cell disease: a chronic inflammatory condition. 1142 23

For various ethnic and socioeconomic reasons the pattern of renal disease in the inner city displays distinctive features. Hypertension is frequent, often intractable, and generally conditioned by salt sensitivity and a high sodium intake. Chronic hypertensive nephrosclerosis, found predominantly in African Americans, comprises marked cardiomegaly, renal shrinkage, and hypertensive retinopathy. It has been overdiagnosed in the past, but actually accounts for less than 20% of end-stage renal disease (ESRD) in African Americans. Malignant hypertension, less frequent nowadays, may cause renal shutdown, which is reversible in a few cases; the heart and kidneys are often of normal size. Idiopathic focal segmental glomerulosclerosis is the most common cause of the primary nephrotic syndrome in blacks, but its incidence has also been rising in whites and Hispanics; it does not respond well to treatment, and almost one half of the patients develop ESRD within 10 years. Systemic lupus erythematosus is also more common in African Americans, in whom the severe proliferative forms of lupus nephritis pursue a more virulent course: one half of such patients develop ESRD in 5 years. Cocaine, the use of which has assumed epidemic proportions, may cause accelerated hypertension, acute renal failure from rhabdomyolysis, and progression of preexisting renal disease. Heroin nephropathy has all but disappeared and has been replaced by human immunodeficiency virus (HIV) nephropathy. The prognosis of HIV-infected patients maintained by dialysis has greatly improved. Sickle glomerulopathy, consisting of mesangial expansion, basement membrane duplication, and the absence of immune deposits, may cause the nephrotic syndrome in 4% of patients with severe sickle cell anemia, heralding death within 2 years in one half of patients and ESRD in two thirds; survival has not improved with dialysis. Diabetes is now the most common cause of ESRD. Familial aggregation of ESRD is frequently encountered. Interventions useful in the general population, such as vascular bypass procedures, should be undertaken with great caution and restraint in dialysis patients.
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PMID:Renal disease in the inner city. 1145 21


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