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Biomedical subjects

M Wirz

Publications and source records attributed to M Wirz.

At least 37 records · Page 2Linked to original sources
PubMed1998

Locomotor pattern in paraplegic patients: training effects and recovery of spinal cord function.

Recent studies have shown that a locomotor pattern can be induced and utilized by paraplegic patients under conditions of body unloading using a moving treadmill. The present study investigated the behaviour of the locomotor pattern and also the relationship of its development to the spontaneous recovery of spinal cord function assessed by clinical and electrophysiological (tibial nerve somatosensory evoked potentials and motor evoked potentials) examinations. The earliest time that spinal locomotor activity could be induced was when signs of spinal shock had disappeared. This activity was distinct from spinal stretch reflex activity. In complete paraplegic patients the locomotor pattern improved spontaneously without training. This was coincident with both an increase of gastrocnemius electromyographic activity during the stance phase of gait and a decrease of body unloading. These effects reached a plateau after about 5 weeks. In complete and incomplete paraplegic patients a near linear increase of gastrocnemius electromyographic activity occurred during the stance phase of a step cycle with daily locomotor training over the whole training period of 12 weeks. This was also coincident with a significant decrease of body unloading. In contrast to this, neither clinical nor electrophysiological examination scores improved after the onset of training in both patient groups. Only in incomplete paraplegic patients was there recovery, albeit statistically insignificant, of spinal cord function according to the sensory and motor scores obtained in the neurological examination during the time period before onset of training. An improvement of locomotor function by training was also seen in patients with paraplegia due to a cauda lesion. Such training effects on muscles and tendons could be separated from those on the spinal locomotor centres. The findings of this study may be relevant for the future clinical treatment of paraplegic patients.

Adolescent↗
PubMed1998

Early participation in an HIV cohort study slows disease progression and improves survival. The Swiss HIV Cohort Study.

BACKGROUND: Different levels of experience of physicians caring for patients with HIV infection have been found to be associated with differences in survival amongst their patients. We examined whether early participation in the Swiss HIV Cohort Study (SHCS), an ongoing prospective study with regular follow-up visits at specialized clinics, improved survival of HIV-infected patients. METHODS: We studied 3553 HIV-infected individuals who joined the Swiss HIV Cohort Study (SHCS) with different levels of immunosuppression: mild (CD4 count above 500 x 106 cells L-1; n x 2038); severe (100-199 cells; n = 960); and very severe (50-99 cells; n = 555). Characteristics at different CD4 cell levels were compared and Cox proportional hazards regression was used to examine the mortality experience during a total of 16 201 person-years of follow-up. RESULTS: Participants joining the cohort early with mild immunodeficiency were younger, more likely to be female, and more likely to have a history of intravenous drug use. At CD4 cell counts below 200 x 106 cells L-1, they were less likely to have a history of Pneumocystis carinii pneumonia or AIDS, more likely to be on prophylaxis against P. carinii and more likely to be on antiretroviral therapy than those joining with severe or very severe immunodeficiency. For example, at the time of the first CD4 cell count in the range of 50-99 x 106 cells L-1, 8.9, 15.0 and 21.6% of participants who joined with mild, severe and very severe immunodeficiency had suffered an episode of P. carinii pneumonia. In Cox models adjusted for CD4 cell count at entry and other relevant baseline differences, mortality was increased amongst participants who joined with severe and very severe immunodeficiency. Hazard ratios (95% confidence intervals (CI)) were 1.71 (1.21-2.42) for participants with severe immunodeficiency at entry and 2.61 (1.70-4. 01) for those with very severe immunodeficiency, compared with 1.0 for those with mild immunodeficiency at entry. CONCLUSIONS: Individuals who were seen regularly at specialized HIV units from early stages of the infection onwards were, at comparable levels of immunodeficiency, less likely to progress to AIDS, and mortality during subsequent follow-up was reduced. This is likely to be explained by better access to prophylactic regimens and antiretroviral therapy.

Adult↗
PubMed1997

Impact of new antiretroviral combination therapies in HIV infected patients in Switzerland: prospective multicentre study. Swiss HIV Cohort Study.

OBJECTIVES: To examine trends in disease progression and survival among patients enrolled in the Swiss HIV cohort study during 1988-96 and to assess the influence of new antiretroviral combination therapies. DESIGN: Prospective multicentre study, with follow up visits planned at six monthly intervals. SETTING: Seven HIV units at university centres and cantonal hospitals in Switzerland. PATIENTS: 3785 men (mean age 35.0 years) and 1391 women (30.3 years) infected with HIV. 2023 participants had a history of intravenous drug misuse; 1764 were men who had sex with men; 1261 were infected heterosexually; and 164 had other or unknown modes of transmission. 601 participants had had an AIDS defining illness. RESULTS: During more than 15,000 years of follow up, there were 1456 first AIDS defining diagnoses and 1903 deaths. Compared with those enrolled during 1988-90, the risk of progression to a first AIDS diagnosis was reduced by 18% (relative risk 0.82 (95% confidence interval 0.73 to 0.93)) among participants enrolled in 1991-2, by 23% (0.77 (0.65 to 0.91)) among those enrolled in 1993-4, and by 73% (0.27 (0.18 to 0.39)) among those enrolled in 1995-6. Mortality was reduced by 19% (0.81 (0.73 to 0.90)), 26% (0.74 (0.63 to 0.87)), and 62% (0.38 (0.25 to 0.97)) respectively. Compared with no antiretroviral treatment, the risk of an initial AIDS diagnosis after CD4 lymphocyte counts fell to < 200 cells x 10(6)/1 was reduced by 16% (0.84 (0.73 to 0.97)) with monotherapy, 24% (0.76 (0.63 to 0.91)) with dual therapy, and 42% (0.58 (0.37 to 0.92)) with triple therapy. Mortality was reduced by 23% (0.77 (0.68 to 0.88)), 31% (0.69 (0.60 to 0.80)), and 65% (0.35 (0.20 to 0.60)) respectively. CONCLUSIONS: The introduction of antiretroviral combination therapies outside the selected patient groups included in clinical trials has led to comparable reductions in disease progression and mortality.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Locomotion in patients with spinal cord injuries.

Following central motor lesions, two forms of reorganization can be observed that lead to improved mobility: (1) the development of increased muscle tone and (2) the activation of spinal locomotor centers induced by specific treadmill training. Tension development is different from normal during spastic gait and appears to be independent of exaggerated monosynaptic stretch reflexes. Exaggerated stretch reflexes are associated with an absence or reduction of functionally essential polysynaptic reflexes. Based on observations of the locomotor capacity of the spinal cat, recent studies have indicated that spinal locomotor centers can be activated and trained in patients with complete or incomplete paraplegia when the body is partially unloaded. The level of electromyographic activity in the gastrocnemius muscle, however, is considerably lower in patients with central motor lesions than in persons without neurological impairments. During the course of a daily locomotor training program, the amplitude of gastrocnemius muscle electromyographic activity increases during the stance phase and inappropriate tibialis anterior muscle activity decreases. Such training programs can improve the ability of patients with incomplete paraplegia to walk on stationary surfaces. This article reviews the pathophysiology and functional importance of increased muscle tone and the effects of treadmill training on the locomotor pattern underlying new attempts to improve the mobility of patients with paraplegia.

Animals↗
PubMed1995

Immunity to diphtheria in the 4-70 year age group in Italy.

Diphtheria antibody level in serum samples obtained from 270 subjects aged 4-70 was measured by in vitro seroneutralization test on Vero cells. Of the studied population, 27.8% had an antibody titre below the protective level (< 0.01 IU/ml). The prevalence of susceptible subjects showed a significant age-related increase (p < 0.01), with the highest value (53.8%) in the 31-40 age group. Mean antibody titre was maximum in individuals aged 13-14, then decreased reaching the minimum level in the 41-50 age group. These data suggest that in individuals aged 30-50, diphtheria immunity is not satisfactory, both for prevalence of immune subjects and for antibody levels. Therefore, a revaccination of adults with reduced doses of diphtheria toxoid may be advisable.

Adolescent↗
PubMed1994

Detection of anti-HCV antibodies in immunoglobulin preparations by recombinant immunoblot assay.

The presence of anti-HCV antibodies in immunoglobulin preparations was investigated by recombinant immunoblot assay (RIBA) and enzyme immunoassay (EIA). While EIA was found to be suitable for detecting anti-HCV antibodies in immunoglobulin preparations, the RIBA could not be used without modifying the standard procedure developed for use with human sera. The two modifications were: (1) incubation with the anti-human IgG conjugate in a single test tube for each strip, instead of in a common vessel; (2) removal of the conjugate after 15 min and its replacement with fresh conjugate for a second 15 min incubation period. Thirty-six immunoglobulin preparations were tested using this modified procedure. Twenty-nine out of 31 (93.5%) preparations received in 1992 were anti-HCV positive, whereas the five immunoglobulin preparations received in 1993 were negative. These results were compared with those obtained on the same samples with the EIA. The percentage of samples positive with EIA was 74.2%. The difference between the results obtained with modified RIBA and EIA was statistically significant (P < 0.05).

Hepatitis Antibodies↗
PubMed1993

Tetanus immunity among Italians born after the introduction of mandatory vaccination of children.

In Italy systematic mandatory tetanus immunization of children started in 1968. In a national sample of 241 young males born after 1968 the prevalence of non-immune subjects was 11.2% (5.5% in the North-Centre, 15.9% in the South-Islands; p < 0.02). Comparing these data with the corresponding figure obtained in a previous study of subjects born before 1968 a significant decrease (11.2% versus 32.6%; p < 0.01) is observed. The prevalence of non-immune subjects born after 1968 is significantly (p < 0.01) lower than that observed in subjects born before 1968 by geographical area as well as by area (urban/rural) of residence. These findings indicate that the introduction of compulsory tetanus vaccination for all newborns has favourably affected the immune status of younger Italian men. However, more efforts should still be addressed to decrease regional inequalities in the delivery of health care.

Adolescent↗
PubMed1992

Tetanus immunity in a partially vaccinated population of children in a district of Naples (Secondigliano).

A general opinion is that compliance with the compulsory immunization programme of children is excellent in Italy. We have studied antitetanus immunity in relation to vaccination history in a sample of 444 school children born between 1977 and 1981 in a district of Naples. Information on vaccination history was collected by interviewing the parents and validated using the official vaccination certificates. Titration of antibodies against tetanus was carried out by the immunoenzymatic method. 0.9% of our study subjects had not been vaccinated at all and only 21.2% had received 4 vaccine doses. In 18 children the presence of antitetanus antibodies was not detected; 14 of them had received one or more doses of vaccine. The lack of compliance with the vaccination programme was associated with a remarkable delay in administering the tetanus vaccine. In the population reported here, the percentage of subjects only partially covered is higher than that found in other regions of Italy.

Child↗
PubMed1991

Detection of anti-HIV antibodies in immunoglobulin preparations: the significance of antibodies to the HIV-envelope.

Four hundred and sixty-eight immunoglobulin preparations, produced between 1969 and 1989, were examined for anti-HIV antibodies by means of two competitive immunoenzymatic assays and the Western blot test. This study refers the results obtained by the three different methods. Such results show that the detection of anti-HIV antibodies in immunoglobulins may be performed on a routine basis using commercial kits intended for human sera. The meaning of the test and the role of antibodies against the HIV envelope proteins are emphasized.

Blotting, Western↗
PubMed1987

Year of birth, sex and residence, as "determinants" of tetanus incidence and immunity in Italy.

Regional results of a seroepidemiological study and official notification data are evaluated to describe the situation of tetanus in Italy. Tetanus incidence has been decreasing during the past years. Vaccination has been the principal means of tetanus prevention. Trend analyses for sex- and age-specific rates suggest a change of exposure, presumably linked to the transformation of the Italian society after the World War II, a higher incidence among the elderly as a function of poor coverage and vanishing immunity. Regional data show remarkable variability in prevalence of susceptible population. Reported rates by region are different. Different degrees of regional underreporting in case notification is suggested.

Adolescent↗
PubMed1987

Immunity to tetanus among Italians born between 1956 and 1963.

Systematic mandatory immunization of children against tetanus begun in Italy in 1968. Preceding birth cohorts, accounting for almost 80% of present Italian population, were poorly immune or totally non-immune; around 90% of cases of tetanus occurring in Italy in recent years are observed among them. In a national sample of 4770 young males born between 1956 and 1963, about one third was not protected. Prevalence of non-immune subjects was greater in the Southern Regions and the Islands, in rural areas, among the unemployed, among the older birth cohorts.

Adolescent↗
PubMed1987

Prevalence of hyperimmunization against tetanus in a national sample of 18-26 year old immune subjects in Italy.

Prevalence of tetanus hyperimmunization was estimated among 3217 immune subjects to be approximately equal to 11%. Hyperimmunization was associated with age, area of residence and health care availability. Indiscriminate administration of booster doses of tetanus vaccine could result in some areas in unnecessary revaccinations and possibly hypersensitivity reactions. The immunization policy regarding booster doses should be based on factual evidence and not on rigid recommendations.

Adolescent↗
PubMed1984

A purified polysaccharide isolated from Candida albicans induces antibody response in vitro by human peripheral blood lymphocytes and discriminates between sera from normal and Candida albicans-infected individuals.

A purified polysaccharide extracted from Candida albicans (MPPS), stimulates in vitro synthesis of specific antibodies by human peripheral blood lymphocytes. These antibodies can be detected by a sensitive enzyme-linked immunoassay. The same assay can be applied to the quantitation of anti-candida antibodies in serum. Statistically significant differences were found between sera of normal and candida-infected individuals.

Adult↗
PubMedDate not supplied

Prevalence of hyperimmunization against tetanus in Italians born after the introduction of mandatory vaccination of children with tetanus toxoid in 1968.

Systematic mandatory immunization of children against tetanus was started in Italy in 1968. Prevalence of tetanus hyperimmunization (> 5 IU/ml) was assessed among 214 immune subjects born after 1968 and found to be 17.3%. This figure is significantly higher (p < 0.01) than the 10.8% found in a previous study of subjects born before 1968. This increase is statistically significant in the Center (p < 0.01) and in the South (p < 0.05) of Italy, but not in the North. Hyperimmunization is not associated with family size (odds ratio 2.16; C. I. 95% = 0.5-7.6) or the father's years of education (odds ratio 1.83; C. I. 95% = 0.6-5.3). No difference was found between urban and rural areas of residence. Indiscriminate administration of booster doses of tetanus vaccine in hyperimmune subjects in some areas could result in unnecessary vaccinations, which can cause hypersensitivity reactions.

Adolescent↗