Search PubMed⌕ Search

Biomedical subjects

C M Poser

Publications and source records attributed to C M Poser.

At least 19 recordsLinked to original sources
PubMed1992

Improvement in motor evoked potentials and clinical course post-steroid therapy in multiple sclerosis.

Motor evoked potentials (MEP) were recorded in 23 patients with definite relapsing multiple sclerosis before and after treatment with a short course of high dose of methylprednisolone. MEP were performed together with clinical examination just before treatment, and 6 and 60 days later. The following results were observed: (1) a statistically significant relationship between the corticospinal deficit and the alteration in MEP, (2) a significant improvement in latency of MEP by day 6, (3) a significant correlation between the change in the Kurtzke disability scale rating and the improvement in MEP. The results provide further evidence for the possible effectiveness of short courses of high dose corticosteroids in the treatment of relapses of multiple sclerosis and the usefulness of MEP in its assessment.

Adult↗
PubMed1992

The epidemiology of multiple sclerosis: the Iceland model. Onset-adjusted prevalence rate and other methodological considerations.

The epidemiology of multiple sclerosis (MS) is characterized by the fact that there is an uneven distribution of the disease throughout the world. The two most commonly used indices of its frequency are the incidence and prevalence rates. The incidence rate reflects, to a great extent, the influence of environmental factors in triggering the clinical manifestations of the disease, if it is based upon the actual date of the initiation of symptoms, rather than the date of diagnosis. The prevalence rate is currently based on the date of diagnosis and includes all MS patients who are alive on a particular date, without regard to their ethnic origin, the site and the duration of residence or any other factors that may have influenced the acquisition of the disease. We propose that in order to make the concept of the prevalence rate possibly more meaningful, the term should refer, retrospectively, to all patients whose symptoms eventually led to the diagnosis of MS, even though the diagnosis was not yet established on an earlier prevalence day. In addition, only patients of the same ethnic background who have spent their prepuberal years in the geographical area under study should be included. We are calling this measure the onset-adjusted prevalence rate. Another problem encountered in epidemiological studies of MS relates to the common practice of adjusting prevalence data obtained for age and sex in one area to what is referred to as a "standard" American (or world) population, groups of great ethnic and age diversity. It is also curious that in many studies the bases for comparison of populations are census data obtained many years previously. We suggest that age and sex adjustment should be applied only to similar ethnic groups born and raised under different environmental conditions. We believe that data obtained by calculating an onset-adjusted prevalence rate restricted to a homogeneous group of patients sharing the same environment during the prepuberal years may provide valuable etiological clues.

Age Factors↗
PubMed1992

Multiple sclerosis. Observations and reflections--a personal memoir.

The pathogenesis of MS has become better understood as a result of recent advances in several areas, particularly in epidemiology and neuro-imaging. A number of epidemiologically based conclusions need to be revised, most importantly the putative direct relationship between prevalence and latitude, and the concept that epidemics of MS have occurred in some parts of the world. It is now clear that genetic factors play a much more important role in the genesis of the disease than environmental factors, although the latter cannot be ignored. The existence of a genetic susceptibility, coupled with either protective or enhancing factors, which may be genetic or environmental, is recognized as being most important in individuals of northern European origin. Much evidence suggests that the disease is initiated by a viral illness (or possibly a vaccination) at some time before puberty. This first antigenic challenge results in the development of what is called the "MS trait", a systemic condition that may never develop into the actual disease and may be observed as well in the unaffected siblings of MS patients. The trait is almost certainly a manifestation of an alteration of the immune system; its most important effect is to render the blood-brain barrier more vulnerable to a variety of agents that will increase its permeability. In order for MS to involve the central nervous system, loss of integrity of the blood-brain barrier is an obligatory step, an observation which has now been amply confirmed by neuroimaging studies. This effect upon the blood-brain barrier appears to be non-specific, since it may result from such diverse causes as a viral infection, a vaccination, or mild trauma. Edema and inflammation follow, but myelinoclasia is not always a consequence; thus plaque formation may not occur and the initial lesion of MS may disappear without leaving a trace. The actual mechanism of myelinoclasia, and the role played in it by lymphocytes, remain unknown. Although the disease does affect the central nervous system, it may remain asymptomatic for a long time after the actual plaque is formed, even for the person's entire life.

Blood-Brain Barrier↗
PubMed1990

Epidemiology of multiple sclerosis in Arabs in Kuwait: a comparative study between Kuwaitis and Palestinians.

On December 31, 1988 there were 201 registered multiple sclerosis patients in Kuwait, an overall prevalence rate (PR) of 10.2 per 100,000; among them were 186 Arabs, of whom 72 were Palestinians and 51 Kuwaitis. Comparison of these two subgroups, who had a similar age distribution revealed that the disease was 2 1/2 times more frequent among Palestinians (PR 23.8/100,000) than among Kuwaitis (PR 9.5/100,000). Palestinians also showed significant differences from Kuwaitis in eye color, blood group distribution and HLA-DR and HLA-DQW epitopes frequency. This suggests that genetic rather than environmental factors might be the underlying cause for the high susceptibility to develop MS among Arabs originating from the Eastern Mediterranean basin.

Adult↗
PubMed1990

Notes on the pathogenesis of subacute sclerosing panencephalitis.

In the original description by van Bogaert and De Busscher of subacute sclerosing leukoencephalitis (SSLE), great emphasis was placed upon the involvement of the white matter, a feature that, in addition to the absence of inclusion bodies, differentiated it from subacute inclusion body encephalitis (SIBE) of Dawson. Subsequently, the common features, primarily clinical, electroencephalographic and immunological led to the consolidation of both into the entity known as subacute sclerosing panencephalitis (SSPE). The white matter lesions of SSLE are identical to those that are seen in progressive rubella encephalitis, subacute AIDS encephalomyelitis, tropical spinal paraparesis due to HTLV-1, and visna of Icelandic sheep, but, more importantly, are characterized by the perivascular edema, inflammation and demyelination known in acute, immune-mediated post-infectious and post-vaccinal acute disseminated encephalomyelitis (ADEM). Furthermore, in SSLE and in the other conditions resulting from a persistent viral infection, deposits of immune complexes can be demonstrated in the walls of small cerebral blood vessels. There is therefore strong evidence to suggest that in SSLE as well as in the other persistent viral infections, in addition to the actual invasion by the virus, there is a contemporaneous immune-mediated response to this virus which is responsible for most, perhaps even all of the disseminated, extensive demyelination observed in these conditions. It is also suggested that SSLE and SIBE, sharing a common etiology, may represent two different phenotypic expressions of the same process.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1990

Multiple sclerosis or HTLV-I myelitis?

Several authors have demonstrated the presence of antibodies against the HTLV-I retrovirus in patients with MS. Considerable controversy exists regarding the etiologic significance, if any, of this finding, but the presence of these antibodies in the blood or CSF of MS patients has led to reconsideration of that diagnosis in certain cases. It is recommended that, before the diagnosis of MS is changed to that of HTLV-I-associated chronic myelitis, at least 2 of the following abnormalities be present: (1) clinical or electrophysiologic involvement of peripheral nerve or muscle; (2) the presence of oligoclonal bands in the serum; (3) the presence in blood or CSF of lymphocytes with multilobed nuclei; (4) a positive serologic test for syphilis; (5) the presence of a sicca syndrome; and (6) the presence of pulmonary lymphocytic alveolitis.

Deltaretrovirus Antibodies↗
PubMed1989

Magnetic resonance imaging in asymptomatic disseminated vasculomyelinopathy.

Two cases of disseminated vasculomyelinopathy (one of acute disseminated encephalomyelitis (ADEM), the other of acute transverse myelitis), are reported because of the persistence, 3 years and 5 months respectively, of abnormalities of magnetic resonance imaging (MRI). These abnormalities remained although in the first case the disease had been essentially asymptomatic from the onset except for one seizure, the patient remaining neurologically intact, whereas in the second case, the patient had made a complete recovery from very serious neurologic dysfunction. The first case illustrates the fact that ADEM may rarely occur without any symptoms, even in the presence of severe imaging abnormalities in both CT and MRI. Neither the persistence of a blood-brain barrier permeability alteration nor gliosis can satisfactorily explain the MRI changes, and thus the pathological significance of areas of increased signal intensity in MRI remains poorly understood and a matter of uncertainty. This report emphasizes the futility of attempting to correlate any kind of clinical observation, laboratory parameter, or effect of therapeutic regimens with changes, or lack thereof, in the MRI in multiple sclerosis and disseminated vasculomyelinopathy.

Adolescent↗
PubMed1988

Analysis of the 'epidemic' of multiple sclerosis in the Faroe Islands. I. Clinical and epidemiological aspects.

The claim has been made that British troops introduced multiple sclerosis (MS), a transmissible disease, into the Faroe Islands during World War II, causing a three-tier epidemic which resulted in the appearance of 32 cases from 1943 until 1973. Assumptions underlying this hypothesis include the belief that the disease was absent from the Faroe Islands before 1940, the view that ascertainment of cases was complete and that Faroese patients who had either been born in Denmark or had been away from the Islands for 3 or more years before the onset of the disease had to be excluded. All the calculations were based on the presumed date of appearance of the first symptoms of MS. We reject the hypotheses of an epidemic and of the transmissibility of MS for several reasons. The most important one is that the date of onset of illness bears no relationship to the probable date of acquisition, which is widely believed to occur between the ages of 5 and 15 years. The criteria for exclusion of cases are arbitrary and instead of the accepted 32 cases, we believe that 42 cases should be counted in all analyses, including at least 2 with onset of illness before 1940. Only 15 of these 42 were in the age range 5-14 years during the British occupation. We cannot accept the statement that the disease was unknown in the Faroes before 1940 and believe that case ascertainment was incomplete in the Islands, which share close geographic, ethnic, and environmental similarities with other North Sea countries of high MS incidence. The theory of transmission is unconvincing and the characteristics of the putative agent unrealistic. The extremely high incidence of disease, which has statistical significance, is based on a very small number of cases in a very small population, and is of very doubtful biological significance.

Adolescent↗
PubMed1988

Analysis of the 'epidemic' of multiple sclerosis in the Faroe Islands. II. Biostatistical aspects.

A series of biostatistical tests were applied to the data upon which the Faroe epidemic hypothesis was constructed. Temporal, cluster analysis using three commonly applied methods were unsuitable because of the very small size of the sample (32 cases of MS). Methods to detect non-random clusters of disease identified a cluster of 16 cases with date of onset between 1941-1950 (p less than 0.05). However, when 1 questionable case of MS was excluded, the resulting cluster did not support the epidemic hypothesis. The overlapping 95% confidence limits of 5- and 10-year based incidence rates of MS, by date of onset (Poisson distribution) argues against the presence of an epidemic. Analysis of the exposure data, i.e. contacts between the Faroese and the British troops, yielded only borderline statistical significance but changing a single case of MS from the exposed to the unexposed category failed to support the exposure theory. All calculations were also carried out using the probable date of acquisition of the disease, between the ages of 5 and 14 years; these also failed to substantiate the hypotheses of epidemic and transmissibility. Since the validity of statistical analysis to test for the presence of epidemics with small sample sizes is not well established, the lack of concordance between the results of the various approaches leads to the conclusion that there was no epidemic of MS in the Faroes.

Adolescent↗