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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Statistical analysis of a limiting dilution assay (LDA) showed that the occurrence of infectious human immunodeficiency virus type 1 (HIV-1)-harboring cells in serially diluted samples of peripheral blood mononuclear cells (PBMCs) of HIV-1-seropositive patients fits the model describing a single-hit Poisson distribution. This observation led to the discovery that there is a direct correlation (r = 0.957) between the number of HIV-1-positive cells and the time when viral culture produces 1 ng of the HIV-1 p24 gag protein per ml. Frequency estimates based on this relationship were highly accurate (P less than 0.01) within the first 15 days of viral culture, which consisted of coculture of 10(6) normal PBMCs with the equivalent number of test PBMCs. This approach was less cumbersome than LDA and was sensitive enough to detect a single infectious HIV-1-harboring cell among as many as 320,000 cells. The values obtained for 57 patients agreed well with the data in the literature and showed that the frequencies of infectious cells in PBMCs reflect the advancement in the clinical stage, being 1/38,000, 1/11,000, and 1/7,000 for asymptomatic patients (Centers for Disease Control [CDC] group II/III), patients with AIDS-related complex (CDC group IVa), and patients with AIDS (CDC group IVb/c), respectively. A nearly 10-fold disparity in mean frequencies was observed when these values were correlated with the numbers of CD4-positive cells (1/9,000, 1/1,500, and 1/300, respectively, for asymptomatic patients, patients with AIDS-related complex, and patients with AIDS). The described method provides a simple means of determining infectious HIV-1-positive cells in blood samples.
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PMID:Relationship between frequency of infectious human immunodeficiency virus type 1-harboring cells and kinetics of viral replication: a simple procedure for quantitation of infectious virus-carrying cells in blood samples. 140 Sep 50

Two patients with Di George syndrome are presented. Diagnosis was done at ages 4 months and 16 days respectively. Their main clinical symptoms were hypocalcemic convulsions, unusual facies (hyperthelorism, low set prominent ears, micrognathia, short philtrum) and cardiac malformations (vascular ring with right aortic arc, aberrant left innominated artery and ligamentum arteriosus in one of them and Tetralogy of Fallot with pulmonary valve atresia in the other). The first patient is now a 3.5 year old boy, his vascular ring was repaired and he has hypoparathyroidism but no clinical nor laboratory evidence of cellular immunodeficiency. The other patient had evidence of heart failure at her second week of life, she died at age sixteen days and, at necropsy, Fallot's tetralogy with pulmonary valve atresia, closed ductus arteriosus, histologically normal ectopic thymus and absent parathyroid glands were demonstrated. We postulate that these cases correspond to partial forms of Di George syndrome.
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PMID:[Di George syndrome]. 184 46

A case of polyarteritis nodosa (PN) in childhood involving various organs such as the gastrointestinal tract, skin, CNS, kidneys and liver with hypogammaglobulinemia is reported. This 6 month old girl was admitted to our hospital with vomiting, diarrhea, bloody stools with mucous and weight loss. For the past 5 months she had these abdominal symptoms. She was diagnosed as having PN of the Kussmaul-Maier variety on the grounds of the biopsy of skin lesion where a necrotizing vasculitis was found. Prednisolone and methylprednisolone pulse treatment were not effective in suppressing the progress of the disease. At the age of 1 year 7 month a combination therapy of prednisolone and immunosuppressants (cyclophosphamide) was started and this was found to be effective. She was discharged when she was 2 year and 2 month. The dosage of prednisolone was tapered as the activity of the PN decreased and she did well with a maintainance dosage of 9.5 mg/day. At 3 year 6 month of age she suddenly developed hypertension (the plasma renin activity was found to be 16.6 ng/m/hr. and the aldosterone 220 ng/dl). CNS involvement such as spinal cord dysfunction, left sided convulsions, cerebral hemorrhage developed 5 months later. Methylprednisolone pulse therapy was performed 3 times and 2 mg/kg/day of prednisolone was administered. In spite of this therapy she passed away with a massive cerebral hemorrhage at the age of 4 year 8 month. Unfortunately an autopsy was not performed. Results of the immunological tests proved that the hypogammaglobulinemia was a common variable immunodeficiency (CVI). It has been reported that primary immuno-deficiency syndrome is often associated with collagen disease and auto-immune disease. This lack of the defense mechanism against the virus or extra antigen could be related to the onset of collagen and auto-immune disease. As the correlation between CVI and PN has not been clarified this case is of interest as concerns the cause of PN.
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PMID:[A case of hypogammaglobulinemia associated with polyarteritis nodosa presenting a variety of symptoms in childhood]. 197 16

The impact of the migrant mine labor system in South Africa on transmission of human immunodeficiency virus (HIV) was assessed by reviewing the literature on epidemiology of sexually transmitted diseases (STDs) and HIV, and interviewing at length 20 male miners and 24 women supporting themselves near the mines as prostitutes or mistresses. Interview subjects were selected by "strategic informant snowball sampling," a type of purpose sampling used in anthropological studies, best for collecting descriptive data. Interviews focused on familial, marital, sexual experiences and perceptions of migrant mine workers and their wives and female partners. While official reports from mine management states that there is little likelihood that HIV will spread among migrant workers and their contracts, STD morbidity rates in these groups have almost doubled between the mid-1970s and mid-1980s, and reports of HIV infection are high in some areas, notably Malawi and Botswana. The HIV prevalence among Malawian migrants rose from 3.8% in 1986 to 21% in 1989, with an African pattern of transmission. The migrant labor system is based on "hostels" where male mine workers live in barracks for long periods or indefinitely, separated from wives and families. Men pass the time drinking and seeking female companionship and sex, either as long-term sexual partners, casual short-term partners, or cash clients. The system takes a toll on marriages, with high rates of divorce and abandonment, leaving many women, who are then rejected by their families, with prostitution as their only subsistence option. People viewed AIDS education messages from mine management with suspicion, often blamed AIDS on the mines or other ethnic groups, and neither sex used or expressed interest in using condoms. Thus this population fits the description in the epidemiology of STDs of a high-risk core group with multiple partners and frequent partner change, and the mobility to be major carriers to urban, suburban and rural areas. It is suggested that AIDS education be initiated by empathetic groups such as trade unions and the African National Congress, by prevent suspicion of racism or genocide as motivation for the campaign.
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PMID:Human immunodeficiency virus and migrant labor in South Africa. 200 69

There have been urgent demands for knowledge about the epidemic of the acquired immunodeficiency syndrome (AIDS) in Australia. Accurate predictions are important for efficient allocation and planning of limited health-care resources. Ideal data for this purpose would be reliable knowledge of the past and present incidence of human immunodeficiency virus (HIV) infection. However, since the incidence of the infection is unknown predictions can only be based on historical data of the incidence of AIDS. In this article, we show the limitations of such predictions by examining a broad range of mathematical models that successfully track the observed data (1187 cases diagnosed to December 31, 1988). In addition, we describe a simple method for prediction in subgroups where the numbers of cases observed so far are small. Four models representing different forms of departure from the simple exponential model provide the best fits to the Australian AIDS data. Regional variability and a possible effect resulting from the introduction of zidovudine were incorporated into the models. Significant regional variability in the course of the epidemic was observed between New South Wales, Victoria and the rest of the country. For Australia as a whole, the doubling time changed from less than one year before mid 1987 to more than two years after this time. Model fits were improved by fitting the models to just the four years of data from 1985. The models give comparable predictions for the first year (1989) of around 600 new cases. However, by 1993 the predictions vary considerably, ranging from 500 to 2300 new cases. It is predicted that between 3100 and 6700 cases are likely to be diagnosed in Australia between 1989 and 1993. The results from the subgroup prediction demonstrate that when the observed number of cases is small, then the range of predictions for a future time interval is very wide. For reliable long-term predictions that are necessary for public health planning, basic information on the past and present incidence of HIV infection is urgently needed.
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PMID:Predicting the course of AIDS in Australia. 221 8

Evolution of viral genes is characterized by enormously high speed compared with that of nuclear genes of eukaryotic organisms. In this paper, the evolutionary rates and patterns of base substitutions are examined for retroviral oncogenes, human immunodeficiency viruses (HIV), hepatitis B viruses (HBV), and influenza A viruses. Our results show that the evolutionary process of these viral genes can readily be explained by the neutral theory of molecular evolution. In particular, the neutral theory is supported by our observation that synonymous substitutions always much predominate over nonsynonymous substitutions, even though the substitution rate varies considerably among the viruses. Furthermore, the exact correspondence between the high rates of evolutionary base substitutions and the high rates of production of mutants in RNA viruses fits very nicely to the prediction of the theory. The linear relationship between substitution numbers and time was examined to evaluate the clock-like property of viral evolution. The clock appears to be quite accurate in the influenza A viruses in man.
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PMID:Molecular clock of viral evolution, and the neutral theory. 226 2

Di George syndrome is caused by anomalous development of the organs arising from the third and fourth pharyngeal pouches and results in congenital aplasia of the thymus, aplasia or hypoplasia of the parathyroid glands and cardiovascular malformations. Clinically, affected children show hypoparathyroidism and, because of depressed cell-mediated immunity, serious bacterial, viral and fungal infections. We present an infant, aged 6 weeks, with convulsions due to hypocalcemia, in which cell-mediated immunodeficiency was detected. Additionally diagnostic and therapeutic possibilities in DiGeorge syndrome are shown.
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PMID:[DiGeorge syndrome--significance of early diagnosis in cellular immunodeficiency]. 387 89

The experimental evidence available for animal and plant RNA viruses, as well as other RNA genetic elements (viroids, satellites, retroelements, etc.), reinforces the view that many different types of genetic alterations may occur during RNA genome replication. This is fundamentally because of infidelity of genome replication and large population sizes. Homologous and heterologous recombination, as well as gene reassortments occur frequently during replication of retroviruses and most riboviruses, especially those that use enzymes with limited processivity. Following the generation of variant genomes, selection, which is dependent on environmental parameters in ways that are poorly understood, sorts out those genome fits enough to generate viable quasispecies. Chance events can also be destabilizing, as illustrated by recent results on fitness loss and other phenotypic changes accompanying bottleneck transmission. Variation, selection, and random sampling of genomes occur continuously and unavoidably during virus evolution. Evolution of RNA viruses is largely unpredictable because of the stochastic nature of mutation and recombination events, as well as the subtle effects of chance transmission events and host/environmental factors. Among environmental factors, alterations resulting from human intervention (deforestation, agricultural activities, global climatic changes, etc.) may alter dispersal patterns and provide new adaptive possibilities to viral quasispecies. Current understanding of RNA virus evolution suggests several strategies to control and diagnose viral diseases. The new generation of chemically defined vaccines and diagnostic reagents (monoclonal antibodies, peptide antigens, oligonucleotides for polymerase chain reaction amplification, etc.) may be adequate to prevent disease and detect some or even most of the circulating quasispecies of any given RNA pathogen. However, the dynamics of viral quasispecies mandate careful consideration of those reagents to be incorporated into diagnostic kits. Broadening diagnosis without jeopardizing specificity of detection will be challenging. There is a finite probability (impossible to quantify at present) that a defined vaccine may promote selection of escape mutants or a particular diagnostic kit may fail to detect a viral pathogen. Of particular concern are the potential long-term effects of weak selective pressures that may initially go unnoticed. Variant viruses resulting from evolutionary pressure imposed by vaccines or drugs may insidiously and gradually replace previous quasispecies. The great potential for variation and phenotypic diversity of some important RNA virus pathogens (human immunodeficiency virus, the hepatitis viruses, the newly recognized human hantaviruses, etc.) has become clear. Prevention and therapy should rely on multicomponent vaccines and antiviral agents to address the complexity of RNA quasispecies mutant spectra.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:RNA virus quasispecies: significance for viral disease and epidemiology. 782 89

The objective of this study was to investigate heterogeneity in incubation distributions in different cohorts and to assess the sensitivity of back-calculated infection rates to different assumptions about incubation times from human immunodeficiency virus (HIV) infection to AIDS diagnosis. Incubation distributions were estimated by using data from three different cohort studies. These and one other published incubation model were used as inputs for a back-calculation procedure that reconstructed smooth HIV-infection rates from AIDS incidence among adults in the United States, allowing for changes over time in incubation. Incubation estimates from the different cohorts differed substantially. The cumulative HIV incidence estimates that result from using the different incubations are very different, but the back-calculated models all produce good fits to the observed diagnosis counts. We conclude that systematic differences in incubation times of different groups add substantially to the uncertainty inherent in using the back-calculation method to reconstruct HIV epidemics and project future numbers of AIDS cases.
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PMID:Different AIDS incubation periods and their impacts on reconstructing human immunodeficiency virus epidemics and projecting AIDS incidence. 846 Jan 23

In this study we estimated past human immunodeficiency virus (HIV) incidence in 19 nations in the primarily English-speaking Caribbean and projected the course of the epidemic to the year 1999. We compared the results obtained from several different models of HIV incidence and different assumed incubation distributions. Linear and nonlinear optimization methods were used to fit several models (power, logistic, spline, and step) to adult (age 15 years or older) AIDS incidence data derived from our existing surveillance system. All four models tested gave good fits to the data, with estimates of cumulative HIV incidence in 1993 ranging from 16,504 to 21,732. An increase in the assumed median of the AIDS incubation distribution by one year increased the estimates of current cumulative adult HIV incidence by approximately 12%; these estimates varied by as much as 6% between models. An adjustment of the data for possible reporting delay increased the estimates by approximately 7% and for underreporting by 25%. Despite their sensitivity to underlying assumptions, back-projection estimates provide useful insights into the patterns of HIV and AIDS incidence. The models indicate that HIV and AIDS incidences in the English-speaking Caribbean have been rising steadily, with adult HIV prevalence in the general population still less than 1%.
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PMID:Back-projection and sensitivity analysis of the HIV-AIDS epidemic in the Caribbean. 852 35


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