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Biomedical subjects

B R Visscher

Publications and source records attributed to B R Visscher.

At least 55 records · Page 3Linked to original sources
PubMed1984

Multiple sclerosis and age at exposure to childhood diseases and animals: cases and their friends.

Eighty-eight multiple sclerosis case-friend pairs were interviewed by telephone to elicit information about early-life exposures. Available mothers were also interviewed. Risk factors included childhood diseases, exposures to animals, and residence. We found a positive association between MS and having measles at a later than usual age. Analysis of the data in the literature showed that this was the third statistically significant association between MS and later age for measles. This is consistent with the hypothesis that the pathogenesis of MS includes an age-dependent host response to measles.

Adult↗
PubMed1984

Multiple sclerosis.

The cause of multiple sclerosis is unknown but seems to be multifactorial. Susceptibility or resistance may be genetically determined; something in the environment interacts with the human host at the proper age to cause biochemical and structural lesions in the central nervous system. The systemic immune response and the response of the central nervous system become involved. Although multiple sclerosis cannot yet be cured, many clues are leading to an effective palliative therapy. Suppression or modulation of the immune responses may be the key to developing that treatment. If the environmental agent is one or several viruses, then antiviral regimens will be appropriate. Research must therefore continue at both basic science and clinical levels.

Adrenocorticotropic Hormone↗
PubMed1983

Relation between sexual practices and T-cell subsets in homosexually active men.

27% of 89 young, non-ill, homosexually active men in Los Angeles had a Leu-3(OKT4)/Leu-2(OKT8) ratio less than or equal to 0 . 8. The low ratio was due to a significantly raised mean number of Leu-2 cells, whereas individuals with acquired immune deficiency syndrome had a decrease in both Leu-3 and Leu-2 cells. The term "acquired immune augmentation" may be appropriate for those with a low ratio due to raised numbers of Leu-2 cells. Those practising passive (receptive) anal intercourse had a significantly higher mean number of Leu-2 cells than did those practising only active (insertive) anal intercourse or no anal intercourse. The results of this study suggest that two distinct conditions occur in homosexually active men. Whether acquired immune augmentation is a precursor of the rarer acquired immune deficiency syndrome or is an unrelated disorder needs to be determined. In this study passive anal intercourse was associated with acquired immune augmentation.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Underlying cause of death as recorded for multiple sclerosis patients: associated factors.

The coding of multiple sclerosis (MS) as underlying cause of death (UCD) on the death certificate provides an important epidemiologic resource for both descriptive and analytic studies. However, not all deaths among MS patients will be so coded. We investigated the effect on estimated occurrence of MS and on characteristics of MS patients when only UCD codes are used to identify cases. Of 2329 MS patients living in Los Angeles County (California) or King/Pierce Counties (Washington) in 1970, 438 had died by 1980. Only 53% of the deaths were coded to MS; 47% were attributed to other causes. Based on our comparisons, the use of only MS-coded deaths to describe decedents would: underestimate the age at MS onset; overestimate the female:male ratio; underestimate age at death; and underestimate duration of MS. Also, the percentage of MS-coded deaths decreased with lengthening duration of follow-up of these prevalent cases. The effect of using only UCD codes to report characteristics of decedents with other chronic diseases may well be similar.

Adult↗
PubMed1982

Factors associated with a malignant or benign course of multiple sclerosis.

Eight hundred thirty-four patients with multiple sclerosis (MS) in King and Pierce Counties, Washington, and in Los Angeles County, California, with symptomatic onset between 1960 and 1969 were followed up for disability status in 1980. A higher proportion of the 375 patients who were not walking or deceased in 1980 had a late age of onset, resided in Los Angeles County, had motor or coordination symptoms at onset, and reported adverse responses to heat exposure and favorable responses to cold exposure, whereas a higher proportion of the 299 patients still walking without aids had early onset age and vision, speech, or sensory symptoms, or all three, at onset. The results suggest (1) that both host factors (age at first manifestation of symptoms and types of symptoms at onset) and environmental factors (place of residence and exposure to heat and cold) are determinants of disease course and (2) that most patients with MS should avoid exposure to heat.

Adult↗
PubMed1982

Factors associated with a rapid course of multiple sclerosis.

A cohort of 886 cases of multiple sclerosis (MS) who had onset between Jan 1, 1960, and Dec 31, 1969, and who were resident in 1970 in either a low-prevalence area (Los Angeles County, California, 560 cases) or in a high-prevalence area (King and Pierce Counties, Washington, 326 cases) were followed up for changes in disability status through Dec 31, 1979. Cases had to meet the modified Schumacher criteria for definite/probable MS and to have had a diagnosis of MS or equivalent by a physician. Onset year of disease was determined by onset of the earliest reported symptom. Disability status was determined at intake by an interviewer-administered questionnaire and in subsequent years by an annual mailed questionnaire (self-reported disability status). Progression to a nonambulatory status or death was significantly greater among (1) patients with an older age at onset, (2) patients with a rapid early course, (3) males, and (4) residents of Los Angeles County.

Adult↗
PubMed1981

Mortality in persons with multiple sclerosis in the Seattle and Los Angeles areas.

Case-mortality and survival rates of more than 2,000 prevalent cases of multiple sclerosis (MS) residing in either Los Angeles County, California, or King and Pierce Counties, Washington, and followed up for 105 months, are reported. Case-mortality at the end 105 months was 16.9% of the total group. All age and sex groups had a lower survival rate than the US general population; this difference was especially pronounced in the high-disability groups. There was a trend toward higher case-mortality in high-disability Los Angeles County patients when compared with high-disability patients from King and Pierce Counties.

Adolescent↗
PubMed1981

Relationship between measles HI titers and an MS susceptibility gene.

Recently published studies of formal linkage analyses strongly suggest that a multiple sclerosis susceptibility (MSS) gene is linked to the HLA region of the sixth chromosome. The objective of this analysis was to investigate whether or not the gene has any demonstrable relationship to the immune status with regard to measles within members of multiple-case MS families. Family members were HLA-typed, and levels of antibodies to measles were determined using the hemagglutination inhibition assay. Since a specific, HLA-defined haplotype within each family is presumably a marker for the MSS gene, family members were characterized as either carrying [(+) controls] or not carrying [(-) controls] the MSS gene by the presence of this specific haplotype. Twenty families were entered into the analyses. Results revealed that the mean titer to measles was not different between (+) and (-) controls, and that MS cases had significantly higher titers than both control groups combined.

Age Factors↗
PubMed1981

Two populations with multiple sclerosis. Clinical and demographic characteristics.

Cross-sectional data from 1,793 cases of definite or probable multiple sclerosis (MS) identified in an extensive population survey in King and Pierce (K-P) Counties, Washington and Los Angeles (LA) County, California, were analyzed. Compared to the U.S. population as a whole, patients were more likely to be divorced and to have more years of schooling. The prevalence of MS was higher for females, and for northern-born, regardless of sex. Reconstructed age-, sex-specific incidence rate estimates for natives of the two areas showed a much higher peak annual incidence occurring in an older age group in K-P than in LA. Earliest symptoms in both areas were numbness in the legs, double vision, and loss of vision in one or both eyes. Weakness in arms, speech difficulties, and urinary incontinence tended to be late symptoms. The overall assessment of disability levels showed more than half of the patients to be fully ambulatory at the time of the first interview, with a somewhat higher proportion of each sex severely disabled in California. The ages of onset tended to be younger in LA than in K-P. The earlier onset of disease and the higher proportion of patients with high disability in Los Angeles County suggest that the course of disease is more malignant in this low-prevalence area.

Adolescent↗
PubMed1981

Similar levels of immune complexes in cases of multiple sclerosis and their unaffected relatives.

To investigate the possible effect of the hypothetical multiple sclerosis susceptibility (MSS) gene on circulating immune complexes, we employed a sensitive assay to test for the presence of immune complexes in sera of MS patients and unaffected relatives classified by the presence/absence of HLA-defined markers for the MSS gene. We found no significant differences between cases and relatives. The results suggest that elevated immune complex levels in MS patients' sera reported by others may not be unique to MS cases, but may represent instead a familial phenomenon. We also report a possible association between the A3 + B7 haplotype and increased immune complexes.

Antigen-Antibody Complex↗
PubMed1981

Multiple sclerosis and multiple moves: an etiologic hypothesis.

A case-control study of the number of childhood changes in residence of multiple sclerosis patients showed that cases had made significantly more moves than had controls. This difference may reflect a greater opportunity for exposure to a rare environmental agent or to multiple closely related agents.

Adolescent↗
PubMed1981

Changes in immune response during responses in MS patients.

Changes in clinical status and in two measures of immune function were followed for 21 months (median) in 106 multiple sclerosis (MS) patients and cohabitant controls. Antibody titers to measles, cytomegalovirus, and herpesvirus 1 and 2, and leukocyte migration inhibition indexes (LMIs) to measles and streptokinase/streptodornase (SKSD) were measured at 3- to 6-month intervals and at time of exacerbation in the index case. There were 36 exacerbations in 25 patients. Mean baseline antibody titers and LMI to measles were higher in cases than in controls. No consistent changes occurred in antibody titers to any of the viruses, non in LMI to SKSD. LMIs to measles were lower in most MS patients during exacerbations than before or after exacerbations. This apparent improvement in cell-mediated immune response to measles only during exacerbations may reflect aberrant immune regulation in MS patients, response to recrudescence of a latent agent, or some other phenomenon as yet undefined.

Antibody Formation↗
PubMed1981

Measles antibody titers in multiple sclerosis patients and HLA-matched and unmatched siblings.

Antibody titers to measles, cytomegalovirus, and herpesviruses 1 and 2 were compared for siblings of multiple sclerosis (MS) patients sharing two, one, and no histocompatibility antigen haplotypes with the case. Significant differences were observed only for measles. Titers were significantly lower in siblings sharing no haplotypes with the case. Within case-sibling pairs, the presence of HLA-A-A3 and/or B7 affected measles antibody titers more than the presence of MS. These findings suggest that the immune response to measles in these sibships is influenced by the presence of HLA-A-A3 and/or B7 as well as another familial factor.

Adult↗
PubMed1980

Genetic susceptibility to multiple sclerosis: a linkage analysis with age-of-onset corrections.

To test the hypothesis that a multiple sclerosis susceptibility (MSS) gene is linked to the HLA loci, formal linkage analysis was conducted on 40 multiplex families, 20 each from the Seattle and Los Angeles areas. The computer program LIPED was utilized. A dominant model of inheritance was assumed. Penetrance values of 0.05, 0.35, and 0.67 were entered into the analyses, and an age-of-onset correction was incorporated. The resulting lod scores were supportive of linkage at the lower penetrance levels. The maximum lod score, 2.411, at an estimated recombination fraction of 0.10 in both males and females, was generated at a penetrance value of 0.05. With a penetrance value of 0.67, the lod scores did not support linkage. Under an autosomal dominant model of inheritance, the results were supportive of linkage when the presumed penetrance of the MSS gene is low. The results also confirmed the importance of incorporating an age-of-onset correction into linkage analyses.

Age Factors↗
PubMed1979

Genetic susceptibility to multiple sclerosis.

Previous studies of histocompatibility (HLA) types in multiple sclerosis (MS) families did not provide convincing proof of an HLA-linked susceptibility factor. In 12 families we studied, all MS cases in each family shared at least one chromosome. The probability of this occurring in the absence of genetic linkage is approximately 0.001. The estimated penetrance is 5 percent, implying that the genetic susceptibility factor may be a necessary but not a sufficient cause of MS. Additional studies are needed to identify other differences between affected and unaffected susceptible individuals.

Female↗
PubMed1979

HLA types and immunity in multiple sclerosis.

HLA types and levels of humoral and cell-mediated immune responses to several antigens were studied in a large group of patients with multiple sclerosis, and in controls. Patients were more likely than controls to have the DRw2 antigen. They had higher mean antibody titers to measles but not to cytomegalovirus, herpes 1, or herpes 2, and had less competent cell-mediated responses. Antibody titers to measles were lower and cell-mediated immune responses were more effective in patients with the DRw2 antigen in patients than in patients without it. This apparent specificity for measles suggests that the etiology of multiple sclerosis is related to the immune response to measles or related viruses.

Antibodies, Viral↗
PubMed1979

Multiple sclerosis and housedogs: a case-control study.

A case-control study was conducted to examine the possible association between ownership of housedogs early in life and later development of multiple sclerosis (MS). Sixty MS patients were compared with 60 neighborhood controls matched for age, sex, and race. There was no significant difference between cases and matched controls in housedog ownership, duration of ownership, or age at first exposure to housedogs over the interval from birth to 19 years of age.

Adolescent↗