PubMed Health⌕ Search

Biomedical subjects

V T Farewell

Publications and source records attributed to V T Farewell.

17 recordsLinked to original sources
PubMed1992

Using serial observations to identify predictors of progression to AIDS in the Toronto Sexual Contact Study.

The Toronto Sexual Contact Study comprises a cohort of 249 male sexual contacts of men with HIV disease which has been followed every 3 months for almost 5 years. On enrollment 143 were seropositive and 16 seroconverted during the follow-up period. By 31 December 1989, 41 of the 159 seropositive cohort members had developed AIDS. Using Cox relative risk regression models, we investigated the association of a number of laboratory and clinical variables and progression to AIDS. Fixed covariate models examined laboratory variables from the enrollment visit of cohort members, with time calculated from this date. In models assessing time dependent covariates, time was calculated from the estimated date of HIV infection. In the univariate models of either fixed or time dependent covariates, many variables were significantly associated with risk of progression to AIDS (T4 cell count, T4/T8 ratio, blastogenic responses to phytohemagglutinin, concanavalin A, and pokeweed mitogen, serum IgA, appearance of p24 antigen, and the development of oral hairy leukoplakia, thrush, or herpes zoster). Appearance of persistent generalized lymphadenopathy was not associated with increased risk of progression. In the multivariate model which evaluated fixed laboratory covariates, T4/T8 ratio, IgA level, and PHA response at enrollment were significantly associated with elevated risk.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS Serodiagnosis↗
PubMed1992

The probability of progression to AIDS in a cohort of male sexual contacts of men with HIV disease.

In a cohort of 249 male sexual contacts of men with AIDS or an AIDS-related condition (ARC), 143 cohort members were seropositive on enrollment and 16 seroconverted during follow-up. A logistic Weibull mixture model was used to estimate the probability of progression to AIDS after HIV infection when infection was assumed to occur during the period of sexual contact with the primary case. Forty cohort members developed AIDS while under study. It appears that at least 50% of men with HIV disease will progress to AIDS and that the best estimate of this probability lies anywhere in the interval 70% to 100%.

Acquired Immunodeficiency Syndrome↗
PubMed1992

HLA alleles in systemic sclerosis: association with pulmonary hypertension and outcome.

HLA antigen distribution was studied in 126 patients with systemic sclerosis (SSc) followed prospectively and compared to that of 325 healthy controls. The frequencies of HLA antigens DR3, DR5 and DRw52 were increased in patients with diffuse skin involvement (P = 0.02, 0.05, 0.03). The presence of DRw52 (relative risk [RR] much much greater than 1) and DRw6 (RR = 54.5) was associated with significantly increased risks of a fatal disease outcome with pulmonary hypertension (PHT). In the absence of PHT, DRw252 was inversely associated with the risk of death. These findings indicate an adverse prognosis in SSc when PHT is present in association with DRw52.

HLA Antigens↗
PubMed1992

Followup in psoriatic arthritis: relationship to disease characteristics.

We investigated whether patient disease characteristics can explain differences in patients registered at the psoriatic arthritis clinic before 1987 who were seen regularly (139, "regular") to those who had not been seen for 2 years before 1989 (165, "inactive"). Despite a higher percentage of women in the regular group (p = 0.0058), logistic regression analysis identified no significant differences in disease severity or treatment at the first or last assessment before 1987. A followup study in 1989 revealed that of the 165 inactive patients, 20 had died and 64 had moved away. Of the 81 remaining patients, 18 were not interested, 18 were seeing other physicians, and 45 returned for followup. The latter 45 patients were compared to 85 of the regular patients who were seen during the same period. Both groups demonstrated similar disease attributes at first and last assessments before 1987. At their 1989 assessments, the same degree of disease progression was noted in both groups. Thus, loss to to followup appears to be random, and should not influence further studies of these patients.

Adult↗
PubMed1992

Chloroquine therapy in psoriatic arthritis.

Our aim was to examine the efficacy of chloroquine in psoriatic arthritis (PsA) and to assess whether chloroquine therapy exacerbated psoriasis. Thirty-two patients had been given chloroquine therapy while attending the University of Toronto Psoriatic Arthritis Clinic. Twenty-four patients continued therapy for at least 6 months, and 18, or 75%, demonstrated > 30% reduction in the actively inflamed joint count. Moreover, there was a significant decrease in the number of actively inflamed joints. A control group, consisting of 24 patients taking no remittive agents, seen during the same period of time, was identified. Only 14, or 58%, of these patients had a > 30% reduction in inflamed joint count over a 6-month period. This pattern was not significantly different (p = 0.19) from the chloroquine treated group. Of the 32 patients who had been given chloroquine, a total of 6 had an exacerbation of psoriasis, only 1 discontinued therapy. There was no case of exfoliative dermatitis. Six of the 24 control patients had an exacerbation of psoriasis. Our experience suggests that chloroquine may be an effective treatment in PsA, and that it does not exacerbate psoriasis. A prospective, randomized, double blind, controlled trial of antimalarial therapy in PsA is warranted.

Administration, Oral↗
PubMed1992

The utility of the arthritis impact measurement scales for patients with psoriatic arthritis.

The Arthritis Impact Measurement Scales (AIMS) consists of 9 scales that measure physical function, pain and psychosocial function. It has been validated for use in various forms of arthritis, but not in psoriatic arthritis (PsA). The AIMS was administered to 145 patients attending our PsA clinic. We carried out simultaneous assessment of clinical measures of function, measures of disease activity, and measures of disease severity. Most scales of physical function were moderately to highly correlated with clinical measures of function (r = 0.33-0.57; p = 0.0001), measures of disease activity (r = 0.24-0.53, p = 0.003-0.0001), and measures of disease severity (r = 0.23-0.6; p = 0.02-0.0001). The pain scale was highly correlated with clinical measures of function and measures of disease activity (r = 0.38-0.58; p = 0.0001) but not with measures of disease severity. Of the psychosocial scales, the depression scale was moderately correlated with clinical measures of function (r = 0.27-0.3; p = 0.001-0.0001). Our data suggest that the physical function and pain scales are good indicators of overall function and disease activity and are valid for use in PsA.

Activities of Daily Living↗
PubMed1992

Psoriatic spondyloarthropathy in men and women: a clinical, radiographic, and HLA study.

Psoriatic spondyloarthropathy as defined by the presence of inflammatory back pain and stiffness, sacroiliitis on physical examination, radiographic evidence of grade greater than or equal to 2 sacroiliitis, and classical or paramarginal syndesmophytes on spinal radiographs was identified in 82 women and 112 men followed at the Psoriatic Arthritis Clinic according to a standard protocol. A logistic regression analysis was performed to look for variables which discriminate between men and women with this condition. No differences in type of peripheral arthritis, degree of damage, or medication were noted between the two groups. However, there was some evidence for more advanced spondyloarthropathy in men. There were no differences in the frequency of HLA B27 or any of the psoriatic arthritis-related HLA antigens. Thus, there may be gender-related differences in the expression of psoriatic spondyloarthropathy, which are unrelated to HLA antigens.

Adult↗
PubMed1991

Kidney biopsy in systemic lupus erythematosus. II. Survival analyses according to biopsy results.

Renal biopsy specimens from 123 patients with systemic lupus erythematosus (SLE) seen between 1970 and 1984 were assessed according to the World Health Organization classification and according to the presence of proliferative, active, or chronic renal lesions. Survival analysis was used to study the determinants of mortality. Survival rates were higher for patients with minimal lesions, intermediate for patients with focal or diffuse proliferative nephritis, and low for patients with glomerular sclerosis. The presence of proliferative and chronic lesions was associated with a higher risk of dying. Renal biopsy results are helpful in predicting prognosis for all-cause mortality in patients with SLE.

Adult↗
PubMed1990

Cofactors of progression to acquired immunodeficiency syndrome in a cohort of male sexual contacts of men with human immunodeficiency virus disease.

In a cohort of 249 male sexual contacts of men with acquired immunodeficiency syndrome (AIDS) or an AIDS-related condition in Toronto, Ontario, Canada, 143 cohort members were seropositive on enrollment and 16 seroconverted between initial recruitment in July 1984 to July 1985 and December 1988. Data on age, smoking and drinking status, recreational drug use, and history of sexually transmitted diseases and other diseases were obtained from interviews at induction and during follow-up on the cohort members every 3 months. Cox relative risk regression models, in which time was calculated from estimated date of human immunodeficiency virus (HIV) infection for seroprevalent cohort members and from 90 days prior to the first positive test for seroconverters, examined the potential effect of use of a variety of recreational drugs and the occurrence of selected infections on the risk of development of AIDS. Thirty-five cohort members developed AIDS while under study. No significant association with risk of progression to AIDS was noted for use of various recreational drugs (singly or in combination), history of specific infections, age at enrollment, or smoking and drinking status at enrollment. Only estimated duration of HIV infection appeared to be associated with increasing risk of development of AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Regression modelling of HLA haplotype sharing in affected siblings.

A link between the HLA system and disease susceptibility can be assessed through the observation of families containing two or more affected siblings. Departures from Mendelian inheritance of the parental haplotypes among the affected siblings are an indication of such a relationship. Other variables, such as environmental factors, may also be related to disease susceptibility. An approach to examining the degree of haplotype sharing and the effect of other variables of interest on observed sharing is presented and two examples analyzed.

Biometry↗
PubMed1986

Marrow transplantation for severe aplastic anemia. Long-term outcome in fifty "untransfused" patients.

Fifty patients with severe aplastic anemia had no transfusions of blood products until just before marrow transplantation from HLA-identical family members. Of the 50, 42 are still alive 1 to 12 years after transplantation (median, 7 years). By actuarial standards, the 10-year probability of survival is 82%. Of the 42 surviving patients, 37 have Karnofsky performance status scores of 100% and 5 with chronic graft-versus-host disease have scores ranging from 50% to 90% (median, 80%). The 8 deaths were caused by early infection in 1, graft rejection in 1, acute graft-versus-host disease in 3, and chronic graft-versus-host disease in 3. All deaths occurred within two years after transplantation. The incidence of graft failure was 10%. Acute graft-versus-host disease developed in 14 of 44 patients at risk and chronic graft-versus-host disease, in 15 of 41. Risk factors for development of chronic graft-versus-host disease included increased age (p = 0.008) and presence of acute graft-versus-host disease (p = 0.001). The only factor associated with increased risk of death was development of acute graft-versus-host disease (p = 0.05). Results of this study extend our previous finding that patients with severe aplastic anemia who have transplants before the onset of transfusion-induced sensitization have an excellent probability of long-term survival and a normal life.

Acute Disease↗
PubMed1985

Anaplastic Wilms' tumor: clinical and pathologic studies.

A review of almost 1,200 children participating in the first and second National Wilms' Tumor Study (NWTS-1 and -2) has demonstrated a number of significant differences in the clinical presentation and response to therapy of anaplastic and nonanaplastic Wilms' tumor. Compared to their counterparts, children with anaplastic Wilms' tumor were generally one to two years older at diagnosis, more were non-white, and more had lymph node metastases at diagnosis. Consistent with previous studies, children with anaplastic Wilms' tumor survived for a significantly shorter time than those with non-anaplastic Wilms' tumor. A hopeful outlook, however, was suggested by the NWTS-2 experience since the more aggressive chemotherapies used in this study appear to have substantially improved the survival of patients with diffusely anaplastic tumors. Also, the survival of NWTS-2 patients with anaplastic Wilms' tumor was determined in part by clinicopathologic stage. It may be possible therefore to refine therapy according to stage so as to provide children with localized disease a chance for cure with fewer untoward treatment-related sequelae.

Anaplasia↗
PubMed1978

Protective environment for marrow transplant recipients: a prospective study.

Laminar air flow isolation and decontamination procedures were evaluated in a prospective randomized study in patients with aplastic anemia or acute leukemia undergoing marrow transplantation from HLA-matched siblings. Patients transplanted in the laminar air flow group had significantly less septicemia and major local infections than did patients in the control group. Nineteen of 46 laminar air flow patients and six of 44 control patients are alive at present. In patients with aplastic anemia the survival was 13 of 17 in the laminar air flow group compared with four of 17 in the control group. In patients with acute leukemia the survival was six of 29 in the laminar air flow group versus two of 27 in the control group. These differences were not statistically significant. Death in both the laminar air flow and control groups was predominantly due to interstitial pneumonitis or recurrent leukemia, which were unaffected by isolation and decontamination.

Acute Disease↗
PubMed1978

The analysis of failure times in the presence of competing risks.

Distinct problems in the analysis of failure times with competing causes of failure include the estimation of treatment or exposure effects on specific failure types, the study of interrelations among failure types, and the estimation of failure rates for some causes given the removal of certain other failure types. The usual formation of these problems is in terms of conceptual or latent failure times for each failure type. This approach is criticized on the basis of unwarranted assumptions, lack of physical interpretation and identifiability problems. An alternative approach utilizing cause-specific hazard functions for observable quantities, including time-dependent covariates, is proposed. Cause-specific hazard functions are shown to be the basic estimable quantities in the competing risks framework. A method, involving the estimation of parameters that relate time-dependent risk indicators for some causes to cause-specific hazard functions for other causes, is proposed for the study of interrelations among failure types. Further, it is argued that the problem of estimation of failure rates under the removal of certain causes is not well posed until a mechanism for cause removal is specified. Following such a specification, one will sometimes be in a position to make sensible extrapolations from available data to situations involving cause removal. A clinical program in bone marrow transplantation for leukemia provides a setting for discussion and illustration of each of these ideas. Failure due to censoring in a survivorship study leads to further discussion.

Bone Marrow Transplantation↗
PubMed1977

The combined effect of breast cancer risk factors.

An extension of the logistic model (Cox, 1970) is applied to the prospective study of breast cancer in Guernsey (Bulbrook and Hayward, 1967). Four important risk factors, age at menarche, family history, age at first birth and etiocholanolone excretion, are identified and shown to have additive effects on a logistic scale for the probability of developing breast cancer. The feasibility of screening a high risk group of women is considered and shown unlikely to be of practical value.

Adult↗
PubMedDate not supplied

Sexual behaviour changes in a cohort of male sexual contacts of men with HIV disease: a three-year overview.

We describe the sexual behaviour reported by 240 seronegative and seropositive homosexual men over a 3-year period. Sexual partners of men with HIV disease were recruited into a prospective study between July 1984 and July 1985 and were monitored every 3 months thereafter. Data on sexual activities were collected through interviewer-administered questionnaires. The cohort experienced a reduction in both the number of sexual partners and the volume of sexual activity. Reductions in the number of partners were early and dramatic. Changes in sexual activities were gradual and consistent in trend. The greatest reduction occurred in high risk activities (receptive and insertive anal intercourse). After 3 years of follow-up, only 10% of the men continue to be exposed to semen through unprotected receptive anal intercourse and 18% through unprotected receptive oral-genital sex. The proportion of men engaging in oral-genital contact and masturbation remained stable over the 3 years. Once informed of their serostatus, both seropositive and seronegative men reduced their high risk behaviour. The decline in rates of STDs and seroconversion confirmed that this cohort had indeed reduced their high risk behaviour.

Cohort Studies↗