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Biomedical subjects

M J Anderson

Publications and source records attributed to M J Anderson.

At least 91 records · Page 5Linked to original sources

The biochemical composition of hemodynamically stressed vascular tissue: the insoluble elastin of experimental arteriovenous fistulae.

Arteriovenous fistulae between the external jugular vein and the common carotid artery were surgically fashioned in eight sheep. The altered hemodynamics produced morphological changes similar to those observed in human atherosclerosis. The elastica is a major mural component and undergoes considerable structural variation during lesion development. The most significant biochemical changes in the elastin occur in the experimental vein region. These include a quantitative loss particularly in the midregion of the vein and a decrease in the concentration of up to 20% of the crosslinks (desmosine and isodesmosine). There is an increase in the cholesterol content of the elastin purified from both experimental artery and vein. The bound phospholipid was higher in the experimental artery and in the dilated experimental vein. There was a significant time-dependent loss of elastin in the stressed venous tissue.

Amino Acids↗

Concurrent outbreaks of influenza and parvovirus B19 in a boys' boarding school.

In the spring term of 1985 there was a protracted outbreak of upper respiratory tract febrile illness consistent with a clinical diagnosis of influenza in a boys' boarding school, which lasted from 23 January to 29 March. Although influenza virus infection was confirmed in 89% of cases in the first half of the term, 53% of the cases which occurred in the second half of the term had no evidence of infection with influenza virus. Between 5 February and 31 March 28 boys presented with skin rashes consistent with a clinical diagnosis of erythema infectiosum; 68% of these were associated with parvovirus B19. Investigation of the cases of clinical influenza with no identified respiratory pathogen revealed a 58% infection rate with B19. B19 DNA was identified in either throat swabs or acute stage bloods of nine pupils with influenza-like symptoms. Cohort studies revealed that 44% of pupils aged 15-16 years were immune before the outbreak compared with only 17% of pupils aged 11-12 years. Infection in the younger group was common and was associated with influenza-like illnesses as well as rashes. Forty-eight per cent of those who did not report any symptoms were also infected with B19.

Adolescent↗

Fetal pathology in human parvovirus B19 infection.

In a current Netherlands study on the effects on mother and child of infection with the human parvovirus B19 during pregnancy, 10 pregnancies have been reported. Three of them ended before term: two in fetal death and one by elective abortion. In two of these fetuses B19 infection in cells other than those of the erythroid series was demonstrated, and in the one terminated, ocular malformation and extensive inflammatory reactions in all fetal and placental tissues were found. The presence of B19 DNA was demonstrated by dot hybridization in placental and fetal tissues. In the third no gross fetal abnormalities were found, although B19 DNA was detected in several fetal tissues by in-situ hybridization. Of the remaining seven pregnancies, six ended at term in the birth of apparently healthy babies. The other child was born near term with a low birthweight and multiple congenital malformations, but with no proof of intrauterine B19 infection. It is concluded that B19 infection in pregnancy can interfere with organ development and may lead to intrauterine fetal death.

Abortion, Induced↗

Anti-DNA and antilymphocyte antibodies during acute infection with human parvovirus B19.

Sera from patients in the acute and recovery stages of parvovirus B19 infection, and from individuals with no detectable antiparvovirus antibody were examined for the presence of anti-DNA and antilymphocyte antibodies. Sixty-eight percent of individuals recently recovered from parvovirus infection had elevated levels of antidouble stranded (ds) and antisingle stranded (ss) DNA antibodies. In addition, a cytotoxic IgM antilymphocyte antibody was detected in more than 88% of these same sera. Serial specimens from volunteers experimentally infected with parvovirus B19 were also tested for these autoantibodies and it was determined that the presence of antilymphocyte IgM was dependent on the stage of infection. The antilymphocyte IgM was occasionally detectable in sera containing rubella specific IgM (11%) or varicella zoster specific IgM (25%). However, in contrast to B19 infection, these antibodies were not cytotoxic. From the results of our study, we propose that parvovirus infection of hematologically normal individuals may be accompanied by a transient, subclinical autoimmune state.

Antilymphocyte Serum↗

A prospective study of acute idiopathic neuropathy. II. Antecedent events.

The incidence of antecedent events and serological evidence of preceding infection were studied in 100 patients with acute idiopathic neuropathy and age and sex matched control subjects in South-East England. Symptoms of respiratory infections occurred within one month before onset of neuropathic symptoms in 38% of patients and 12% of controls (p less than 0.001) and symptoms of gastrointestinal infections in 17% of patients and 3% of controls (p less than 0.005). Immunisations, insect bites and animal contact were equally common in the patient and control subjects. Eight per cent of patients had undergone an operation within the preceding 3 months. Six per cent of patients had co-existing "autoimmune" diseases. Serological evidence of recent infection was identified in 31% of patients. Campylobacter jejuni (14%) and cytomegalovirus (11%) were both significantly more frequently demonstrated in patients than controls. Serological evidence of recent infection with mycoplasma (1%), Epstein Barr virus (1-2%) and parvovirus B19 (4%) was also identified in the patients but not more frequently than in the controls. Possible explanations for the association of these agents with acute idiopathic neuropathy include possession of antigens shared with myelin and inhibition of suppressor mechanisms.

Adolescent↗

Some effects of water quality on the performance of high yielding cows in an arid climate.

The water from wells in Saudi Arabia is often high in mineral content. The cows in this study had been receiving water containing between 4000 and 5000 ppm total dissolved solids. Four groups of 16 cows were calved down and milked under similar conditions in the hot summer months. Two of the groups were given normal well water and the other two groups received water after desalination in a reverse osmosis plant. One group on each type of water also had their water cooled. The groups of cows receiving treated water drank more water, consumed more concentrate and produced significantly more milk than the groups given normal well water. A similar effect on feed intake and milk production was seen when treated water was given to a 1000-cow unit with a similar number of control cows.

Animals↗

Explant cultures of teleost spinal cord: source of neurite outgrowth.

The source of neurite outgrowth in explant cultures of normal adult Apteronotus spinal cord was examined. Explants which contained the central region of spinal cord, including ependyma, showed neurite outgrowth in culture. Explants which did not contain ependyma showed no neurite outgrowth. It is concluded that the ependymal region is necessary for neurite outgrowth in these cultures of adult teleost spinal cord. In addition, our failure to observe axon outgrowth clearly attributable to fluorescently back-labeled electromotor neurons in these cultures suggests that the exuberant neurite outgrowth in vitro is most probably due to cells other than the electromotor neurons. This explant culture system provides a unique opportunity to study neuronal differentiation, regeneration, and neurogenesis in vitro.

Animals↗

Human parvovirus infections.

Discovered by chance in 1974, the human serum parvovirus B19 is at present the only recognized, autonomous, pathogenic human parvovirus. For some years following its discovery, B19 was not associated with any defined clinical syndrome; although a high titre viraemia was often noted in infected individuals they were largely asymptomatic. In 1980 the causal association between B19 infection and aplastic crisis in chronic haemolytic anaemia began to emerge with the discovery of B19 as the agent responsible for aplastic crisis in sickle cell anaemia. This fulfilled the expectation of a disease of tissue comprising a large proportion of dividing cells, namely the erythropoietic elements of the bone marrow, anticipated in autonomous parvovirus infection where viral replication is confined to dividing cells. More recently, erythema infectiosum, an illness sharing many of the clinical features of rubella, has been found to be the common result of B19 infection, although a spectrum of disease is now emerging. Much effort is currently directed toward the elucidation of the effects of maternal B19 infection on the developing fetus.

Anemia, Hemolytic↗

Molecular differentiation of neurons from ependyma-derived cells in tissue cultures of regenerating teleost spinal cord.

Cells cultured from the caudalmost area of regenerating teleost spinal cord differ both morphologically and in terms of molecular architecture from those of more rostral (more fully differentiated) areas of the cord. The caudalmost regenerating cord consists of an ependymal tube. Cells from this region have flattened or partially flattened cell somas and short spike projections in vitro; they do not exhibit the rounded cell somas nor the long, thin, branching neurites typical of differentiated neurons. A series of cultures taken from different areas along the length of regenerating spinal cord were examined for molecular differentiation by staining with a monoclonal antibody against non-phosphorylated neurofilament protein (SMI 32). None of the cells from the caudalmost culture of the regenerating spinal cord stained with antibody SMI 32. In cultures of more rostral regenerated cord, the cells with neuronal morphology do stain positively with the anti-neurofilament antibody. This result suggests that the cells in the cultures of caudalmost cord represent relatively undifferentiated ependymal cells, or ependyma-derived cells, which later differentiate into neurons and glia in the regenerating spinal cord.

Animals↗

Parvovirus infection in hospital practice.

Eleven cases of human parvovirus (HPV) infection were diagnosed on the basis of positive IgM serology over a 9-month period in two London hospitals. These cases accounted for almost 30% of viral illness in which HPV serology had been requested. Ten of the cases presented with joint symptoms and/or rash and one case presented with evidence of a severe autoimmune haemolytic anaemia. Six patients had lymphadenopathy. Clinical and laboratory features of the cases are presented. HPV DNA was sought but not found in synovial fluid from one patient.

Antibodies, Viral↗

Parvovirus associated aplastic crisis in homozygous sickle cell disease.

Aplastic crises in homozygous sickle cell disease in Jamaica predominantly affect children and occur in epidemics. Of 67 cases in a cohort study of 314 children with homozygous sickle cell disease, 62 were attributable to human parvovirus infection. Affected children were aged 0.5-12.5 years, and the incidence rose to 28% by 10 years. No recurrences were seen. Symptoms and signs on presentation were attributable to the viraemia and acute anaemia. Asymptomatic thrombocytopenia was common. Blood transfusion was given in 54 cases (87%). Thirty eight children (61%) were admitted to hospital, 16 of whom were extremely ill on presentation and one of whom died soon after admission. Twenty four (39%) were managed as outpatients, 16 of whom were transfused. Parvovirus associated aplastic crisis is a self limited condition with excellent prognosis if diagnosed promptly and managed appropriately.

Anemia, Aplastic↗