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Biomedical subjects

M E Thomas

Publications and source records attributed to M E Thomas.

At least 55 records · Page 3Linked to original sources
PubMed1980

Human lymphocyte markers defined by antibodies derived from somatic cell hybrids. II. A hybridoma secreting antibody against an antigen expressed by human B and null lymphocytes.

A hybridoma (FMC4) has been derived which secretes antibody showing selective reaction with human B lymphocytes, monocytes and some null lymphocytes. Few, if any, T lymphocytes in normal blood are stained, although stimulation of lymphocytes with PHA leads to an increase in the proportion of cells reacting with the hybridoma antibody. The antibody reacts with B and null lymphoblastoid cell lines but not with T cell lines. B chronic lymphocytic leukaemia (CLL) cells but not T-CLLs are stained and null-type acute lymphoblastic leukaemia (ALL) cells but not T-type ALL also react. Normal blood myeloid cells do not react with FMC4 supernatant whilst some myeloid leukaemias do. The expression of the antigen reacting with FMC4 supernatant suggests that FMC4 may secrete an antibody against the human equivalent of the Ia antigen.

Antibodies↗
PubMed1978

Humoral and cell-mediated immunity to Histoplasma capsulatum during experimental infection in neotropical bats (Artibeus lituratus).

The humoral and cell-mediated immune responses of the large, frugivorus bat, Artibeus lituratus, were studied following intraperitoneal injection of 10 or 10(4) viable mycelial particles of Histoplasma capsulatum. Most bats had both cultural and histologic evidence of disease at autopsy. Utilizing a technique designed to measure the volume of footpad swelling in hypersensitive bats a significant degree of delayed hypersensitivity to histoplasmin was evident in both groups 4 to 6 wk after infection. Precipitating antibodies first appeared in the serum 3 wk after infection, but only in the animals infected with 10(4) viable organisms. Both the double diffusion and counterimmunoelectrophoresis techniques for antibody gave identical results. These findings suggest that A. lituratus is very susceptible to infection with H. capsulatum, and that a mild infection will stimulate delayed hypersensitivity to the organism but only low levels of antibody. The footpad test utilized in this study may be a sensitive and practical method for detecting natural infection in bats.

Animals↗
PubMed1975

Diarrhoea in general practice: a sixteen-year report of investigations in a microbiology laboratory, with epidemiological assessment.

Results are presented of the laboratory examination of faeces specimens from 20,273 patients with acute diarrhoea. These were household index cases seen in general practice in a London borough during the years 1953-68. An annual average of about 2 per cent of households in the area were affected, but there was considerable fluctuation with year and season. Half the patients were children although only one-fifth of the population at risk was under 15 years of age. The greatest incidence of diarrhoea was among children under 5 years old. Male children, but female adults predominated. Specimens were sent for laboratory diagnosis at the discretion of the general practitioner. The laboratory found some abnormality in nearly a third and there were indications that transmissible infection was involved in about one-fifth of patients. The most common diagnosis was Sonne dysentery (9 per cent) which came in epidemic waves and made its greatest impact among young school children. Microscopy was useful, and giardiasis was diagnosed in 1-4 per cent of index patients. Other parasites were less commonly found. Fatty globules characteristic of an infectious condition we have called 'fatty diarrhoea' were frequently observed by microscopy in stools from young children and occasionally from older persons. Blood or pus cells were seen in less than half the shigella and salmonella infections and in a much smaller proportion of the remainder. A test for occult blood performed on specimens from all patients of 40 years or older was positive, in the absence of visible red cells, in a tenth of these cases. Other studies on the bacteriology of diarrhoea in general practice are referred to and some epidemiological comparisons made. The possible place of unidentified infective agents in the aetiology of undiagnosed diarrhoeas and of 'fatty diarrhoea' is discussed.

Adolescent↗
PubMed1973

Dysentery in general practice: a study of cases and their contacts in Enfield and an epidemiological comparison with salmonellosis.

During a laboratory study of diarrhoea in a large urban area during the years 1953-68, 5319 Sonne dysentery infections in 2620 households and six cases of Flexner dysentery in five households were confirmed. The annual incidence per 10,000 population fluctuated between 2 and 31 with an average of 12.Shigella sonnei was found in 10% of new cases of diarrhoea investigated. Plural infections were found in 58% of the households studied and 30% of all contacts examined were shown to be infected. Among these contacts the infection rate was higher for children (42%) than adults (20%), and higher for adult females (24%) than males (16%). The duration of infection was under 2 weeks in nearly half the index cases followed up and longer than 2 months in only 3%. Intermittent excretion was observed in 15%. Repeated Sonne dysentery infection and illness was observed after intervals as short as 5 months. Antibiotic sensitivity was recorded after 1955 and colicine typing after 1960. Changes in antibiotic sensitivity were noted. Children of primary-school age were most susceptible to Sonne dysentery, but symptoms in ill cases were as severe in adults as in children. During years of high incidence cases were concentrated within a small number of primary schools.Sh. sonnei infections were compared with salmonella infections studied concurrently. Sonne dysentery was a winter disease and most cases were under 11 years old, and case-to-case infection was the usual means of spread. Salmonellosis was prevalent in summer and affected nearly as many adults as children, often persons sharing an article of food. It was more prolonged and severe than Sonne dysentery, but less infectious. In all these respects S. typhimurium occupied an intermediate place between Sonne dysentery and ;other salmonellas'.

Adolescent↗
PubMed1973

Sonne dysentery in day schools and nurseries: an eighteen-year study in Edmonton.

A study of Sonne dysentery infections in 19 primary and 11 secondary day-schools and 4 day-nurseries has been made over a period of 18 years in an urban area. Measures were taken throughout to try to prevent and control outbreaks. Sonne dysentery was not endemic in the school population and, even at times of high incidence, epidemics were localized within a few of the primary schools, usually in the spring or autumn terms. Incidence rates of Sonne dysentery were highest in primary schools with large infant departments and in nurseries. Secondary schools entirely escaped outbreaks.The co-operation of head teachers was engaged for all precautionary measures in schools. A policy of immediate exclusion of suspected and infected children was useful in preventing and controlling school epidemics of dysentery. Toilet hygiene was often poor in schools with outbreaks, and this was found to be a profitable field for applying control measures. Infected kitchen workers were only occasionally involved.Recommendations are given in the light of this study, and some reference is made to the more difficult problem posed by dysentery outbreaks in day-nurseries, where temporary closure may be the best policy. It is important that responsibility for infectious disease control in schools be clearly delineated in the reorganized health services of 1974. Teachers can play an important part in limiting infection.

Adolescent↗
PubMed1972

Contamination of an operating theatre by gram-negative bacteria. Examination of water supplies, cleaning methods and wound infections.

This paper describes a search for Gram-negative bacteria in an operating theatre and the steps taken to reduce the level of environmental contamination.A high rate of infection in clean wounds prompted a bacteriological survey. Potential sources of infection found, and the measures employed are described in the hope that others may be encouraged to examine familiar equipment critically and to improve hygiene even in old premises.The choice, design, use and care of cleaning and sterilizing equipment were open to criticism. In particular, a currently popular floor-scrubbing machine provided a breeding ground for Pseudomonas aeruginosa and was distributing it in the theatre environment.

Humans↗
PubMed1972

An epidemiological study of strains of Shigella sonnei from two related outbreaks.

During the winter of 1967-8 Sonne dysentery affected neighbouring North London primary schools. This was not simply due to cross-infection between the two schools, for two different, unusual strains of Sh. sonnei were distinguished. One was a novel kanamycin-resistant colicine type 7 strain, and as far as we know this was the first school outbreak due to such a strain to be documented. The other strain was kanamycin-sensitive and of colicine type 0 with a rare specific requirement for aspartic acid. There was some evidence to suggest that the kanamycin-resistant strain was more infective for adults and possibly more pathogenic than the kanamycin-sensitive.Studies on the transfer of drug resistance and of colicinogeny revealed that the factor determining colicine type 7 was carried on a transmissible plasmid, a new observation. Various drug resistances were also transmissible experimentally, and some were spontaneously unstable. Non-transferable ampicillin-resistance in the colicine type 7 strain and aspartic acid dependence in the colicine type 0 strain enabled all but one of the isolates to be classified into two distinct lines. No common ancestor was found and it was concluded that although occurring together they must have arisen from separate sources.

Adult↗
PubMed1971

Metabolic responses to oral glucose in the Kalahari Bushmen.

The plasma glucose, immunoreactive insulin, and growth hormone levels after a 50-g oral glucose load have been measured in 15 adult Bushmen subjects living in the Kalahari region of Southern Africa. Compared with 10 non-obese white controls, they showed relative glucose intolerance and significantly impaired insulin secretion. Growth hormone responses showed no significant differences between the two groups. Factors such as inadequate or unusual nutrition and stress do not appear to account completely for the abnormalities in carbohydrate metabolism observed in the Bushmen. Of interest are the clinical and hormonal similarities that seem to exist between the Bushmen and the Central African Pygmies.

Adolescent↗
PubMed1970

Salmonellosis in general practice. Observations of cases and their household in Enfield.

Nine hundred and seventeen Salmonella infections in 580 households were confirmed during a laboratory study of diarrhoea in general practices in a large urban area during the years 1953-68. This was an annual incidence of about 2/10,000 population. Salmonellas were found in nearly 2% of new cases of diarrhoea investigated. Plural infections were found in 36% of the households studied and 18% of all contacts examined were shown to be infected. Among these contacts the infection rate was higher for children (24%) than for adults (16%). The duration of infection was longer than 2 months in nearly a quarter of the cases followed up, and intermittent excretion was observed in one-fifth. The commonest serotype was Salmonella typhimurium, but its incidence in the district declined especially after 1964. S. typhimurium infection provoked a severer enteritis but less general symptoms than did other salmonellas. Children were more susceptible than adults to salmonella infection, to illness and to prolonged excretion, but symptoms in index cases were as severe in adults as in children.

Adolescent↗