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1.
AIDS Res Ther ; 18(1): 24, 2021 04 28.
Article in English | MEDLINE | ID: mdl-33910592

ABSTRACT

BACKGROUND: The first 90 of UNAIDS 90-90-90 targets to have 90% of the people living with HIV know their status is an important entry point to the HIV treatment cascade and care continuum, but evidence shows that there is a large gap between males and females in this regard. It is therefore important to understand barriers and facilitators of achieving the first 90 target. This study examined determinants of the first 90 target among females and males in order to inform strategies aimed at improving the HIV cascade in South Africa. METHODS: The data used in the analysis were obtained from a 2017 household-based cross-sectional nationally representative survey conducted using a multi-stage stratified cluster random sampling design. A series of hierarchical multiple logistic regression models were fitted to identify the determinants of the first 90 target by gender. RESULTS: Overall, 84.8% of HIV-positive individuals aged 15 years and older were aware of their HIV status. Females were significantly more aware of their HIV status compared to males (88.7% vs 78.2%, p < 0.001). Both females aged 25 to 49 years [aOR = 3.20 (95% CI 1.35-7.57), p = 0.008], and 50 years and older [aOR = 3.19 (95% CI 1.04-9.76), p = 0.042] and males aged 25 to 49 years [aOR = 3.00 (95% CI 1.13-7.97), p = 0.028], and 50 years and older [aOR = 7.25 (95% CI 2.07-25.36), p = 0.002] were significantly more likely to know their HIV status compared to those aged 15 to 19 years. Males with tertiary education level were significantly more likely to be aware of their HIV positive status [aOR = 75.24 (95% CI 9.07-624.26), p < 0.001] compared to those with no education or with primary level education. Females with secondary [aOR = 3.28 (95% CI 1.20-8.99), p = 0.021] and matric [aOR = 4.35 (95% CI 1.54-12.37), p = 0.006] educational levels were significantly more likely to be aware of their HIV positive status, compared to those with no education or with primary level education. CONCLUSION: Significant progress has been made with regards to reaching the UNAIDS first 90 target. In this context achieving the first 90 target is feasible but there is a need for additional interventions to reach the males especially youth including those with no education or low levels of education.


Subject(s)
HIV Infections , Adolescent , Cross-Sectional Studies , Family Characteristics , Female , HIV Infections/drug therapy , HIV Infections/epidemiology , Humans , Male , Prevalence , South Africa/epidemiology
2.
S Afr Med J ; 110(9): 894-902, 2020 08 11.
Article in English | MEDLINE | ID: mdl-32880275

ABSTRACT

BACKGROUND: The COVID-19 outbreak is in an accelerating phase, and South Africa (SA) has had the highest number of documented cases during the early phase of the pandemic in sub-Saharan Africa. OBJECTIVES: To assess South Africans' understanding of and response to COVID-19 during the first week of the country's lockdown period. METHODS: An online survey was conducted in SA from 27 March to 2 April 2020. The survey was distributed widely among several websites and social media networks, including on a data-free platform. Descriptive statistics of knowledge, risk perception, access to and trust in information sources, and public and media opinions were calculated. Estimates were benchmarked to the 2019 national adult population estimates. RESULTS: Of the 55 823 participants, the majority (83.4%) correctly identified the main symptoms of COVID-19. Over 90% had correct knowledge of the incubation period, with lower rates for 18 - 29-year-olds. Knowledge of symptoms and the incubation period varied significantly by population group (p<0.001), dwelling type (p<0.001) and sex (p<0.001). A quarter (24.9%) perceived themselves as at high risk of contracting COVID-19. Risk perception varied by age, population group, employment status and dwelling type (p<0.001). The most prevalent COVID-19 information sources were government sources (72.9%), news websites/apps (56.3%), satellite television (51.6%) and local television (51.4%). CONCLUSIONS: Understanding knowledge, attitudes and behaviours of people facing the COVID-19 pandemic is crucial for guiding strategic policy. These findings provide public understanding of COVID-19 as the phases of the country-level epidemic progress, and also directly inform communication needs and gaps.


Subject(s)
Coronavirus Infections/prevention & control , Coronavirus Infections/physiopathology , Coronavirus Infections/transmission , Health Knowledge, Attitudes, Practice , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Pneumonia, Viral/physiopathology , Pneumonia, Viral/transmission , Access to Information , Adolescent , Adult , Aged , Betacoronavirus , COVID-19 , Female , Hand Disinfection , Health Policy , Humans , Internet , Male , Mass Media , Middle Aged , Public Opinion , SARS-CoV-2 , South Africa , Surveys and Questionnaires , Trust , Young Adult
3.
S. Afr. med. j. (Online) ; 0:0(0): 1-9, 2020.
Article in English | AIM (Africa) | ID: biblio-1271067

ABSTRACT

Background. The COVID-19 outbreak is in an accelerating phase, and South Africa (SA) has had the highest number of documented cases during the early phase of the pandemic in sub-Saharan Africa.Objectives. To assess South Africans' understanding of and response to COVID-19 during the first week of the country's lockdown period.Methods. An online survey was conducted in SA from 27 March to 2 April 2020. The survey was distributed widely among several websites and social media networks, including on a data-free platform. Descriptive statistics of knowledge, risk perception, access to and trust in information sources, and public and media opinions were calculated. Estimates were benchmarked to the 2019 national adult population estimates.Results. Of the 55 823 participants, the majority (83.4%) correctly identified the main symptoms of COVID-19. Over 90% had correct knowledge of the incubation period, with lower rates for 18 - 29-year-olds. Knowledge of symptoms and the incubation period varied significantly by population group (p<0.001), dwelling type (p<0.001) and sex (p<0.001). A quarter (24.9%) perceived themselves as at high risk of contracting COVID-19. Risk perception varied by age, population group, employment status and dwelling type (p<0.001). The most prevalent COVID-19 information sources were government sources (72.9%), news websites/apps (56.3%), satellite television (51.6%) and local television (51.4%).Conclusions. Understanding knowledge, attitudes and behaviours of people facing the COVID-19 pandemic is crucial for guiding strategic policy. These findings provide public understanding of COVID-19 as the phases of the country-level epidemic progress, and also directly inform communication needs and gaps


Subject(s)
COVID-19 , Health Knowledge, Attitudes, Practice , South Africa
4.
Int J Equity Health ; 18(1): 167, 2019 10 30.
Article in English | MEDLINE | ID: mdl-31666077

ABSTRACT

BACKGROUND: In South Africa, persistence of the HIV epidemic and associated gender and racial disparities is a major concern after more than 20 years of democratic dispensation and efforts to create a more healthy and equal society. This paper profiles HIV prevalence and related factors among Black African men and women compared to other race groups in South Africa using the 2012 population-based national household HIV survey. METHODS: This secondary data analysis was based on the 2012 population-based nationally representative multi-stage stratified cluster random household sample. Bivariate and multiple logistic regression analysis were used to assess the relationship between HIV prevalence and associated factors by gender and racial profile. RESULTS: Overall HIV prevalence was significantly higher (p < 0.001) among both Black African males (16.6%; 95% CI: 15.0-18.4) and females (24.1%; 95% CI: 22.4-26.0) compared to their counterparts from other races. Among Black African males, increased risk of HIV was significantly associated with age group 25-49 years and those 50 years and older compared with young males 15-25 years. Among all males, reported condom use at last sex was significantly associated with increased risk of HIV. High socio-economic status (SES) and perceived risk of HIV were associated with a decreased risk of HIV. Among female condom use at last sex and ever testing for HIV was associated with increased prevalence of HIV only among Black African females. Lower prevalence of HIV was associated with marriage, tertiary education, high SES, having a partner five years younger, perceived risk of HIV, and awareness of HIV status among Black African females. CONCLUSION: Gender and racial disparities rooted in structural and contextual inequalities remain important factors for the maintenance of the generalized HIV epidemic in the country. HIV prevention interventions need to cut across all strata of society but also target risk factors salient for specific groups. Alleviating vulnerability to HIV along gender and racial lines should also be viewed as part of a broader public health strategy.


Subject(s)
HIV Infections/epidemiology , Health Surveys/statistics & numerical data , Racial Groups/statistics & numerical data , Adolescent , Adult , Cluster Analysis , Female , Humans , Male , Middle Aged , Prevalence , Risk Factors , Sex Distribution , South Africa/epidemiology , Surveys and Questionnaires , Young Adult
5.
BMC Public Health ; 18(1): 198, 2018 01 30.
Article in English | MEDLINE | ID: mdl-29378557

ABSTRACT

BACKGROUND: In South Africa, HIV is increasingly becoming a chronic disease as a result of advances in HIV treatment and prevention in the last three decades. This has changed the perception from a life threating to a potentially manageable disease. However, little is known about self-perceived health status of HIV-infected individuals. Self-rated health (SRH) has been shown to be a sensitive indicator of health-relatedchanges directly linked to HIV, but can also be influenced by differences in social and material conditions. The aim of this paper was to identify determinants of excellent/good SRH among HIV-infected individuals using socio-demographic, life style and health related data. METHODS: The study used data from the nationally representative 2012 South African population-based household survey on HIV prevalence, incidence and behaviour conducted using multi-stage stratified cluster sampling design. Bivariate and multivariate logistic regression models were used to identify determinants of SRH among HIV-infected individuals. RESULTS: Out of a total of 2632 HIV positive participants 74.1% (95% CI: 68.4-74.2) reported excellent/good SRH. Increased likelihood of reporting excellent/good SRH was significantly associated with being Black African [OR= 1.97 (95%CI: 1.12-3.46), p = 0.019] and belonging to least poor household [OR= 3.13 (95%CI: 1.26-7.78), p = 0.014]. Decreased likelihood of reporting excellent/good SRH was significantly associated with those aged 25 to 34 years [OR= 0.49 (95% CI: 0.31-0.78), p = 0.003], 35 to 44 years[OR= 0.27 (95% CI: 0.17-0.44), p < 0.001], 45 to 54 years [OR= 0.20 (95% CI: 0.12-0.34), p < 0.001], and those 55 years and older [OR= 0.15 (95% CI: 0.09-0.26), p < 0.001], hospitalization in the past twelve months [OR= 0.40 (95% CI: 0.26-0.60), p < 0.001]. CONCLUSION: To have positive health effects and improve the perceived health status for PLWH social interventions should seek to enhance to support for the elderly HIV-positive individuals, and address the challenge of socio-economic inequalities and underlying comorbid conditions resulting in hospitalization.


Subject(s)
Diagnostic Self Evaluation , HIV Infections/epidemiology , Adolescent , Adult , Age Factors , Comorbidity , Female , HIV Infections/therapy , Hospitalization/statistics & numerical data , Humans , Male , Middle Aged , Prevalence , Socioeconomic Factors , South Africa/epidemiology , Surveys and Questionnaires , Young Adult
6.
Public Health ; 143: 1-7, 2017 Feb.
Article in English | MEDLINE | ID: mdl-28159020

ABSTRACT

OBJECTIVES: In Sub-Saharan African countries, including South Africa, uptake of human immunodeficiency virus (HIV) testing among men remains a major challenge. Few studies have explored HIV testing uptake among men and factors that influence their testing behaviours. This article explores trends in HIV testing uptake and associated factors among men aged 15 years and older in South Africa using national HIV population-based household surveys conducted in 2005, 2008 and 2012. STUDY DESIGN: A multistage cross-sectional design was used in the three nationally representative household-based surveys. METHODS: P-trend Chi-squared statistic was used to analyze changes in HIV testing in relation to demographic factors, and HIV-related risk behaviours across the three surveys. Univariate and multivariate logistic regression models were used to assess the associations between ever testing for HIV, demographic factors and HIV-related risk behaviours. RESULTS: HIV testing uptake among men was 28% in 2005, 43% in 2008 and 59% in 2012. A trend was also observed in HIV testing by sociodemographic factors, but differences existed within variables. HIV testing uptake was mainly influenced by the effects of selected population characteristics. Reduced likelihood of HIV testing was significantly associated with males aged 15-24 years, Black African race group, being single and unemployed, those residing in urban informal and rural informal areas, and those men who ever had sex. CONCLUSION: The observed sociodemographic differentials suggest that an effective expansion strategy for HIV testing needs to prioritize those most unlikely to test as identified by the current findings.


Subject(s)
HIV Infections/diagnosis , Mass Screening/statistics & numerical data , Mass Screening/trends , Adolescent , Adult , Cross-Sectional Studies , Health Care Surveys , Humans , Male , Middle Aged , Socioeconomic Factors , South Africa/epidemiology , Young Adult
7.
Int J STD AIDS ; 22(11): 674-9, 2011 Nov.
Article in English | MEDLINE | ID: mdl-22096055

ABSTRACT

We examined the relationship between HIV prevention beliefs related to male circumcision and sexual behaviour/sexually transmitted infection (STI) acquisition among traditionally circumcised men in Cape Town, South Africa. HIV-negative men (n = 304), circumcised for cultural/religious reasons, attending a health clinic in Cape Town, South Africa, completed cross-sectional surveys. Generalized linear models were used to analyse the relationships between unprotected vaginal sex acts, number of female sexual partners, STI diagnoses and male circumcision-related beliefs and risk perceptions. Men who were aware that circumcision offers protection against HIV (relative risk [RR] = 1.19, 95% confidence interval [CI] = 1.06-1.32, P < 0.01), endorsed risk compensation related to male circumcision (RR = 1.15, 95% CI = 1.11-1.12, P < 0.01) and perceived lower risk of HIV infection when circumcised (RR = 1.08, 95% CI = 1.04-1.12, P < 0.01) were more likely to report unprotected vaginal sex acts. Similar patterns were also identified when predicting number of female sexual partners. Men who were more likely to endorse risk compensation related to male circumcision were also more likely to be diagnosed with a chronic STI (odds ratio [OR] = 1.64, 95% CI = 1.06-2.53, P < 0.05). Our findings suggest that we must not overlook the effects of beliefs towards male circumcision for HIV prevention among men traditionally circumcised; doing so may undermine current efforts to reduce HIV transmission through male circumcision.


Subject(s)
Circumcision, Male/statistics & numerical data , HIV Infections/epidemiology , HIV Infections/prevention & control , Health Knowledge, Attitudes, Practice , Risk-Taking , Sexual Behavior/statistics & numerical data , Adult , Cross-Sectional Studies , Female , Humans , Male , South Africa/epidemiology
8.
Sex Transm Infect ; 85(6): 411-5, 2009 Oct.
Article in English | MEDLINE | ID: mdl-19429569

ABSTRACT

BACKGROUND: Anal intercourse is an efficient mode of HIV transmission and may play a role in the heterosexual HIV epidemics of southern Africa. However, little information is available on the anal sex practices of heterosexual individuals in South Africa. PURPOSE: To examine the occurrence of anal intercourse in samples drawn from community and clinic settings. METHODS: Anonymous surveys collected from convenience samples of 2593 men and 1818 women in two townships and one large city sexually transmitted infection (STI) clinic in Cape Town. Measures included demographics, HIV risk history, substance use and 3-month retrospective sexual behaviour. RESULTS: A total of 14% (n = 360) men and 10% (n = 172) women reported engaging in anal intercourse in the past 3 months. Men used condoms during 67% and women 50% of anal intercourse occasions. Anal intercourse was associated with younger age, being unmarried, having a history of STI, exchanging sex, using substances, having been tested for HIV and testing HIV positive. CONCLUSIONS: Anal intercourse is reported relatively less frequently than unprotected vaginal intercourse among heterosexual individuals. The low prevalence of anal intercourse among heterosexual individuals may be offset by its greater efficiency for transmitting HIV. Anal sex should be discussed in heterosexual HIV prevention programming.


Subject(s)
Sexual Behavior/statistics & numerical data , Adolescent , Adult , Ambulatory Care Facilities , Condoms/statistics & numerical data , Female , HIV Infections/epidemiology , HIV Infections/transmission , Heterosexuality/statistics & numerical data , Humans , Male , Risk Factors , Self Disclosure , Sexually Transmitted Diseases/epidemiology , South Africa/epidemiology , Urban Health , Young Adult
9.
SAHARA J ; 2(2): 267-76, 2005 Jul.
Article in English | MEDLINE | ID: mdl-17601009

ABSTRACT

South Africa urgently needs HIV prevention interventions that can be disseminated for use in clinical and community settings. A brief theory-based HIV risk reduction counselling intervention originally developed in the USA has recently been adapted for use in a South African sexually transmitted infection clinic. The 60-minute risk reduction counselling intervention was grounded in the Information-Motivation-Behavioural Skills (IMB) model of HIV preventive behaviour change, adapted through a series of interdisciplinary collaborative workshops. This paper reports the process of developing and culturally adapting the brief risk reduction counselling intervention. The processes used for adapting the HIV risk reduction counselling for South Africa provides a potential model for conducting technology transfer activities with other HIV prevention interventions. Several lessons learned from this process may help guide future efforts to transfer HIV prevention technologies.


Subject(s)
Counseling , HIV Infections/prevention & control , Health Education , Risk Reduction Behavior , Ambulatory Care Facilities , Humans , International Cooperation , Motivation , South Africa , United States
10.
Water Sci Technol ; 43(7): 239-46, 2001.
Article in English | MEDLINE | ID: mdl-11385853

ABSTRACT

The use of an objective function based on fuzzy ecological effect expectation in a genetic optimisation algorithm to obtain site or situation specific stressor attenuation values for the management of diverse stressors emanating from several sources is investigated. The approach is based on the premise that both regulator and regulatee are able to formulate their goals in fuzzy terms. In the case of the regulator the goals will be formulated in terms of acceptability of levels of ecological concern (a fuzzy analogy to ecological risk). In the case of the regulatee it will be formulated in terms of acceptability of the level of attenuation, which is also the control variable. A hypothetical catchment is used to illustrate the principle.


Subject(s)
Computer Simulation , Ecosystem , Environmental Monitoring/methods , Fresh Water/analysis , Algorithms , Environment , South Africa , Water Pollutants, Chemical/analysis
12.
Ecotoxicol Environ Saf ; 31(2): 164-72, 1995 Jul.
Article in English | MEDLINE | ID: mdl-8521783

ABSTRACT

Queletox, containing fenthion as active ingredient, is the avicide formulation used in South Africa to control red-billed finches (Quelea quelea). Control measures involve night spraying of roosting areas with a light aircraft. Since roosting areas often include reedbeds along riversides and on islands, proper control is difficult without exposing the aquatic environment to some risk of contamination. This study tested the acute effects of fenthion, in association with the queletox formulation, on the cladocerans Daphnia pulex and Ceriodaphnia dubia and the fish species Poecilia reticulata, Tilapia rendalli, Cyprinus carpio, and Oreochromis mossambicus. The chronic effects of fenthion on D. pulex were evaluated in a 14-day reproduction test. Mean 48-hr LC50 values estimated for D. pulex and C. dubia were 1.30 and 1.72 micrograms liter-1 respectively. For the fish estimated 96-hr LC50 values were as follows: 2.12 (P. reticulata), 2.53 (C. carpio), 2.92 (T. rendalli) and 1.71 micrograms liter-1 (O. mossambicus). In the chronic test reproduction of the exposed population was stimulated at the lowest two fenthion concentrations (0.1 and 0.6 ng liter-1), while a reproductive impairment was recorded at concentrations varying from 1 to 10 ng liter-1. Concentrations of fenthion measured in dams after spraying are given to indicate the levels of contamination that may occur. QSAR was used to estimate the toxicity of some fenthion metabolites. The results of this study reveal that fenthion, at the concentrations occurring in the environment after aerial spraying, can have marked effects on the survival and reproduction of D. pulex for long periods after spraying.


Subject(s)
Fenthion/toxicity , Insecticides/toxicity , Water Pollutants, Chemical/toxicity , Animals , Carps/metabolism , Chromatography, Gas , Daphnia/drug effects , Dose-Response Relationship, Drug , Female , Fresh Water/chemistry , Insecticides/analysis , South Africa , Species Specificity , Tilapia/metabolism , Tissue Distribution , Water Pollutants, Chemical/analysis
13.
Clin Chim Acta ; 230(1): 1-8, 1994 Oct 14.
Article in English | MEDLINE | ID: mdl-7850987

ABSTRACT

Two patients, diagnosed with 3-methylglutaconic aciduria, who presented with diverse clinical and metabolic manifestations, were studied. Glycine conjugation as a possible detoxification mechanism in these two patients yielded negative results. Carnitine conjugates were however detected. 3-Methylglutarylcarnitine was observed in the urine of both patients, while one of the patients excreted detectable quantities of 3-methylglutaconylcarnitine, a previously unknown metabolite. The presence of this metabolite in urine samples from one patient and the apparent correlation between administered carnitine and the conjugate excretion profile seems to indicate that carnitine may play an important role in future therapeutic programmes.


Subject(s)
Acidosis/urine , Carnitine/analogs & derivatives , Glutarates/urine , Acidosis/drug therapy , Carnitine/therapeutic use , Carnitine/urine , Chromatography, Gas , Female , Fibroblasts/enzymology , Fibroblasts/metabolism , Glycine/analogs & derivatives , Glycine/urine , Humans , Hydro-Lyases/metabolism , Infant , Male , Spectrometry, Mass, Fast Atom Bombardment
14.
J Exp Med ; 154(5): 1332-41, 1981 Nov 01.
Article in English | MEDLINE | ID: mdl-6795300

ABSTRACT

Rat skin that survives for long periods of time on immunosuppressed mice becomes resistant to anti-graft serum and remains so for as long as it survives. When long-standing grafts are removed and placed on new immunosuppressed mice, they remain resistant to antiserum for as long as they survive. The acquired resistance to antiserum seems, therefore, to be due to changes in the grafts rather than to changes in their hosts. Furthermore, it was found that the acquisition of resistance is correlated with replacement of graft endothelium by host cells, as demonstrated by the use of immunofluorescent techniques in conjunction with mouse anti-rat serum and rat anti-mouse serum. Evidently, humoral antibodies are able to cause acute damage to skin grafts, and presumably to grafts to other organized tissues, only if they react with antigens of graft endothelium. Long-term grafts that are retransplanted to their original donors or to rats syngeneic with those donors are in most cases rejected, whereas 14-d-old grafts similarly regrafted are in no case rejected. Apparently, the responses of the secondary recipients to the mouse endothelial antigens in long-term grafts lead to destruction of the entire grafts. When long-standing rat skin xenografts are removed and placed on untreated mice syngeneic with the primary hosts, they are in every case rejected, although they survive slightly longer than skin taken directly from rat donors. Rejection is accompanied by a mononuclear infiltrate and is qualitatively indistinguishable from the rejection of freshly prepared rat skin. Clearly, sensitized cells are more efficient than humoral antibody in destroying grafted tissues.


Subject(s)
Skin Transplantation , Transplantation, Heterologous , Animals , Complement C3 , Graft Rejection , Graft Survival , Immune Sera/pharmacology , Immunoglobulins/administration & dosage , Immunosuppression Therapy , Long-Term Care , Mice , Mice, Inbred A , Rabbits , Rats , Rats, Inbred BN , Rats, Inbred F344 , Rats, Inbred Lew , Skin/blood supply
15.
J Exp Med ; 154(5): 1319-31, 1981 Nov 01.
Article in English | MEDLINE | ID: mdl-7028911

ABSTRACT

Rat skin grafted onto immunosuppressed mice is resistant to mouse anti-rat serum during the first 7-10 d after transplantation. It gradually acquires susceptibility, reaching a peak of sensitivity at 14-16 d after grafting. The grafts remain sensitive to antiserum, though at decreasing levels for an additional 3 wk, and grafts that persist beyond that time are resistant to antiserum for as long as they survive. In the study reported here, it is shown that the initial period of resistance to antiserum is due to factors acting locally within the graft and is entirely uninfluenced by the regimen of immunosuppression or the protective dressings that are used. After administration of antiserum, deposits of the injected immunoglobulin and of endogenous C3 are found on the luminal surfaces of graft vessels, although no significant tissue damage is observed. Rat skin that has become highly sensitive to antiserum 14-16 d after transplantation loses that sensitivity if it is regrafted to a new recipient, and then regains it 8-10 d later. Thus, the resistance of freshly grafted skin to antisera is associated with the process of healing into place, a conclusion that is supported by the observation that the intracutaneous administration of antisera to rats causes intense local inflammation and necrosis. The skin is therefore sensitive just before it is removed for grafting, but temporarily loses sensitivity thereafter. Resistance to antiserum during the first 3 or 4 d after transplantation is probably attributable to the fact that at that time grafts are vascularized poorly if at all. The state of resistance extends for several days after vascularization of the graft takes place and is then only gradually lost, a phenomenon that seems to be associated with the resistance of newly formed and regenerating blood vessels to vasoactive substances. This view is in accord with and, indeed, supports the idea that the induction of vascular injury is an essential step in antisera-mediated damage to tissue grafts.


Subject(s)
Skin Transplantation , Animals , Bandages , Complement C3 , Graft Survival , Immune Sera/administration & dosage , Immune Sera/pharmacology , Immunoglobulins , Immunosuppression Therapy , Inflammation/immunology , Injections, Subcutaneous , Mice , Mice, Inbred Strains , Rabbits , Rats , Rats, Inbred BN , Rats, Inbred Lew , Skin/blood supply , Time Factors
18.
J Immunol ; 114(3): 933-8, 1975 Mar.
Article in English | MEDLINE | ID: mdl-1089727

ABSTRACT

Rat skin transplanted to mice or to allogeneic rats can be acutely and severely damaged by injecting the graft recipients with alloimmune serum of appropriate specificity. This susceptibility of rat skin to alloantisera has been obscured in previous studies by the fact that the extent of serum-mediated damage that occurs is decisively influenced by the interval of time between placement of the grafts and the injection of antiserum. Grafts are resistant to damage during the 1st week after transplantation; they rapidly develop sensitivity during the 2nd week, reaching a peak at 14 to 16 days; and during the next few weeks the sensitivity is lost. Grafts surviving beyond 35 to 40 days become totally resistant to antisera. LBNF1 GRAFTS Are more resistant than Le or BN grafts to BN anti-Le serum or Le anti-BN serum, respectively. However, combinations of the two sera can act synergistically to destroy LBN skin that has been grafted to immunosuppressed mice. This form of serum-mediated tissue damage is thought not to play a significant role in skin graft rejection in the usual circumstances of transplantation since cell mediated immunity is well developed before the acquisition by the grafts of sensitivity to humoral agents. Furthermore, antisera from animals that have rejected a single graft have little or no destructive potential, and hyperimmune animals reject skin very shortly after grafting, often before the grafts have become vascularized and hence before they are sensitive to antiserum.


Subject(s)
Graft Rejection , Immune Sera , Skin Transplantation , Transplantation, Heterologous , Animals , Cytotoxicity Tests, Immunologic , Isoantibodies , Male , Mice , Rabbits/immunology , Rats , Rats, Inbred BN , Rats, Inbred Lew , Skin/pathology , Thymectomy , Thymus Gland/immunology , Time Factors
19.
J Exp Med ; 137(4): 893-910, 1973 Apr 01.
Article in English | MEDLINE | ID: mdl-4120896

ABSTRACT

A study has been made of the roles played by complement and polymorphonuclear leukocytes (PMN) in the acute destruction of xenografts of rat skin that follows injection of their hosts with antisera specifically reactive with graft antigens. The rat skin was grafted onto mice whose immune responses were suppressed by removal of the thymus and a brief course of treatment with rabbit antimouse lymphocyte serum. At about 2 wk after grafting the mice were injected intravenously or intraperitoneally with mouse antirat serum (MARS). This time interval was chosen because it avoided the complications that might be associated with either the process of healing in or with incipient rejection. Signs of graft damage were evident as early as 10 min after the injection of MARS, and in most animals so injected the grafts were completely destroyed within 24-48 h. The role of complement (C) in this acute destructive process is indicated by the results of three lines of experimentation. (a) Non-C-fixing antibodies or antibody fragments failed to cause damage to the grafts. Indeed, both chicken antirat serum and F(ab')(2) fragments from rabbit antirat serum completely protected the grafts against the effects of MARS that was administered 24 h later. (b) When mice were depleted of hemolytic C by treatment with cobra venom factor or heat-aggregated gamma globulin, the damage caused by MARS was greatly reduced or completely inhibited. (c) In mice with a genetically determined absence of C5 much greater quantities of MARS were required to cause graft damage; the tempo of the destructive process was consistently slower; and a greater number of grafts recovered from the initial inflammatory process than was the case for animals with an intact complement system. The participation of PMN in serum-mediated destruction of grafts was initially suggested by the results of microscope examination of fixed tissues. The essential role of these cells in the process is indicated by the failure of MARS to cause tissue damage in mice whose circulating PMN have been reduced to very low levels by treatment with nitrogen mustard or more specifically with an anti-PMN serum. The absence of tissue damage when circulating PMN are reduced but C levels are normal suggests that C-mediated cytolysis is unimportant in graft destruction and that the role of C lies in its ability to generate chemotactic factors. The latter may then attract the PMN that provide mediators of tissue damage.


Subject(s)
Antibodies , Complement System Proteins , Graft Rejection , Leukocytes/immunology , Skin Transplantation , Transplantation, Heterologous , Animals , Antilymphocyte Serum , Chickens/immunology , Cytotoxicity Tests, Immunologic , Female , Hemolysis , Immune Sera , Immunoglobulin G , Immunosuppression Therapy , Male , Mice , Mice, Inbred Strains , Pepsin A/pharmacology , Rats , Rats, Inbred BN , Rats, Inbred Lew , Rats, Inbred Strains , Snakes , Thymectomy , Venoms , gamma-Globulins
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