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Biomedical subjects

T F Jackson

Publications and source records attributed to T F Jackson.

At least 55 records · Page 3Linked to original sources
PubMed1985

Seroepidemiological study of antibody responses to the zymodemes of Entamoeba histolytica.

In 303 apparently healthy subjects and 54 patients with confirmed invasive amoebiasis amoebae were isolated where possible, and Entamoeba histolytica was classified into its various zymodems. 20% of the healthy subjects were antibody-positive; 17 healthy subjects proved to be symptomless carriers of pathogenic zymodemes and, like patients with invasive disease, all these were seropositive. Furthermore, of subjects infected with pathogenic zymodemes 94-100% were strongly seropositive, compared with 2-4% of subjects with non-pathogenic zymodemes. Pathogenic zymodemes are therefore believed to be in constant contact with the host's tissues, even in symptom-free individuals; the presence of these potentially invasive organisms is thought to be directly related to the seropositivity in a given population, and seroepidemiological surveys would therefore provide information only on the distribution of this form of the parasite. Quantitative serological data constitute valuable information on the endemicity of an area, and the results will gain reliability from use of two complementary tests instead of one.

Antibody Formation↗
PubMed1985

Frequency distribution of Entamoeba histolytica zymodemes in a rural South African population.

To determine the prevalence of Entamoeba histolytica and its zymodeme distribution pattern, isoenzyme electrophoresis was performed on isolates of the parasite from 1381 individuals of the population of a semirural endemic area south of Durban. About 10% of the population was found to harbour E histolytica. The zymodeme distribution was similar to that described in other surveys but two new zymodemes were observed, a non-pathogenic zymodeme XIX and a pathogenic zymodeme XX. Non-pathogenic zymodemes were more frequent in females than in males. In apparently healthy individuals there was a 1% prevalence of pathogenic E histolytica; the distribution was the same in males and females even though invasive amoebiasis was far more common in males. Symptoms of amoebic colitis subsequently developed in only 2 of the 14 symptomless individuals from whom pathogenic zymodemes of E histolytica were isolated.

Adolescent↗
PubMed1985

Cell-mediated immunity in hepatic amoebiasis.

Cell-mediated immunity (CMI) was measured by blastic transformation of peripheral blood lymphocytes in 26 patients with amoebic liver abscess (ALA) and matched control subjects with no demonstrable clinical amoebiasis. During active disease, the mean mitogenic response, measured by the stimulation index of the patients' lymphocytes to Entamoeba histolytica antigen, was increased (mean +/- SD: 25.98 +/- 46.62 compared with 11.27 +/- 21.39), whereas that to phytohaemagglutinin (PHA) was reduced (54.80 +/- 56.26 compared with 111.70 +/- 70.61). Both these results were statistically significant (P less than 0.01); they do not, however, appear to be due to a quantitative defect in T-cell numbers, as both total peripheral lymphocytes (3332 +/- 1450 cells/microliters compared with 2447 +/- 531 cells/microliters) and T-cells (2652 +/- 1128 cells/microliters compared with 1908 +/- 386 cells/microliters) were significantly elevated in the patients (P less than 0.01). When these tests were repeated two months later in 12 cured patients they were found to be comparable to those of the control subjects. The results indicate that there is a transient cellular sensitization to amoebic antigen together with an increase in T-lymphocytes and an impairment of the mitogenic response of lymphocytes to PHA. The significance of these findings is discussed.

Adolescent↗
PubMed1984

Concomitant and secondary bacterial infection of the pus in hepatic amoebiasis.

In a series of 48 consecutive patients with clinically diagnosed uncomplicated amoebic liver abscess (ALA), the pus obtained by closed drainage of the abscess was bacteriologically sterile. Secondary bacterial infection of the ALA as a direct result of the aspiration procedure occurred in only 1 patient, the causative organism being Escherichia coli. Entamoeba histolytica was identified in a total of 39 cases (81%) by means of direct microscopy of the pus as well as culture methods.

Amebiasis↗
PubMed1984

Computer literacy in today's medical center environment.

The need for computer literacy is becoming increasingly important across the broad scope of the American work scene. At the Wilford Hall USAF Medical Center (WHMC) numerous computer systems have been introduced into the operational environment. Training for these systems has been restricted primarily to transaction processing and routine report generation for those actually involved as users of these systems. WHMC has developed and implemented a broad computer literacy program designed generally to raise the computer literacy of the overall staff, and specifically to inform executive and middle management of the general capabilities of the computer systems. The program consists of a brown-bag lunchtime videotape theater on a series of computer-related subjects as well as formal classes developed in a modular format. Each formal class is tailored to the specific needs of the target executive or middle-management group.

Administrative Personnel↗
PubMed1984

Serological differentiation between past and present infection in hepatic amoebiasis.

The indirect fluorescent antibody (IFA) test and the amoebic gel diffusion (AGD) test were assessed as tools for differentiating between past and present infection in invasive amoebiasis; in the case of the IFA test the Entamoeba histolytica-specific IgG and IgM were monitored. In a pilot study in which sera from 56 patients with suspected invasive amoebiasis were tested the IgM was positive in 40% of confirmed intestinal and 83% of confirmed hepatic cases, the IgG and AGD were positive in all confirmed cases. A subsequent study was then carried out, in which the tests were used to monitor longitudinally antibody levels of patients with confirmed amoebic liver abscess, from the time of admission to hospital, to one year after successful treatment. The specific IgM levels became negative sooner than the IgG or AGD, with more than half the subjects giving negative results at six months and all cases becoming negative 46 weeks after treatment. The results of this study suggest that the presence of specific IgM, together with specific IgG and a strongly positive AGD test, is indicative of an active infection; conversely, when the IgM is negative, while the other tests are positive, active disease was usually absent.

Dysentery, Amebic↗
PubMed1983

False-positive reactions in the serological diagnosis of schistosomiasis.

Stool and urine samples from children living in an area in the Western Transvaal in which human schistosomiasis was not endemic were examined for parasites and the indirect fluorescent antibody test was performed on their sera. Since none of these children passed any schistosome ova in their excreta but approximately half of them had a positive serological reaction they must have been infected with either Schistosoma mattheei, which is common in snails and cattle in the area, or avian schistosomes. In view of the occurrence of such 'false-positive' results, general practitioners are advised not to rely too heavily on serological tests in the diagnosis of schistosomiasis.

Adolescent↗
PubMed1983

Application of the leucocyte adherence inhibition test to the assessment of cell mediated immunity in invasive amoebiasis.

The leucocyte adherence inhibition (LAI) test was assessed as a means for measuring specific cell mediated immunity (CMI) in invasive amoebiasis. The LAI test and the amoebic gel diffusion (AGD) test were performed on 20 patients admitted to hospital with amoebic liver abscess (ALA) and 24 control subjects with no demonstrable clinical amoebiasis. The AGD results were acceptable for such a study in an endemic area as all the proven ALA subjects gave positive responses while all except one of the controls gave a negative reaction. A percentage adherence in the LAI test of more than 80% was considered to be negative and the mean percentage adherence of leucocytes for the control subjects was found to be 86.0 +/- 4.9 while that for the experimental group was found to be 76.1 +/- 15.4; the difference between these groups is statistically significant. It was noticed that the LAI test response was possibly linked with severity of disease in the ALA subjects. The LAI test has been found to be a relatively rapid test of specific CMI and although fastidious, it does not require the use of radio-isotopes.

Female↗
PubMed1983

Getting there.

Explore the source record for details and available documents.

Computers↗
PubMed1983

A comparative scanning electron microscope study of the teguments of adult male. Schistosoma mansoni, S. margrebowiei and S. leiperi.

Scanning electron microscopy was used in a comparative study of the teguments of adult male Schistosoma mansoni, S. leiperi and S. margrebowiei. The dorsal surface of the teguments of S. leiperi and S. margrebowiei exhibited less spination than that of S. mansoni. The tubercles of S. margrebowiei varied from ellipsoidal to hemispherical while those of S. mansoni were consistently ellipsoidal and divisible morphologically into two types. The dorsal surface of the neck of S. mansoni is traversed by four longitudinal rows of sensory receptors while 2 rows of small tubercles with associated sensory receptors extended along the lateral margin of the neck of S. leiperi.

Animals↗
PubMed1982

Biochemical homogeneity of Entamoeba histolytica isolates, especially those from liver abscess.

The electrophoretic mobility patterns of four enzymes from trophozoites of Entamoeba histolytica were examined to determine the zymodeme of the amoebae populations involved. E. histolytica populations from aspirated liver pus belonged exclusively to types II and XI of eighteen zymodemes. E. histolytica from cases of amoebic dysentery--i.e., those patients presenting with intestinal ulceration and/or with haematophagous trophozoites in the faeces--also belonged to zymodemes II and XI. However, symptom-free cyst passers harboured E. histolytica belonging to one of several zymodemes none of which corresponded wth the zymodemes of the patients with liver abscesses or amoebic dysentery.

Dysentery, Amebic↗
PubMed1982

A zymodeme study of Entamoeba histolytica in a group of South African schoolchildren.

Using a biphasic culture medium, stocks of intestinal amoebae were isolated from a group of children attending school in Durban, South Africa. These were compared with stocks collected in other areas of the world already characterized using the electrophoretic patterns of four enzymes: glucose phosphate isomerase (GPI), phosphoglucomutase (PGM) L-malate: NADP+ oxido-reductase (oxalacetate-decarboxylating) (ME) and hexokinase (HK). 33% of 94 samples grew Entamoeba histolytica, only one of which gave a pattern indicative of a pathogenic stock. Entamoeba hartmanni, Dientamoeba fragilis and Entamoeba coli were also grown from some samples, increasing the total positive samples for all species isolated to 40%.

Adolescent↗
PubMed1980

Schistosoma haematobium egg output and an evaluation of the indirect fluorescent antibody technique.

Results of the indirect immunofluorescent antibody test (IFAT) and output of Schistosoma haematobium eggs have been compared in 112 selected Black schoolchildren living in an endemic schistosomiasis area. The helminth filter was used for the determination of levels of infection. The degree of correlation between the IFAT and egg output improved considerably when multiple urine examinations were performed. There were a number of false-positive results, all associated with low titres; the possible reasons for their occurrence are discussed.

Adolescent↗
PubMed1976

A demonstration of the presence of anti-snail antibodies in individuals infected with Schistosoma haematobium.

An extract of the snail Bulinus (Physopsis) africanus, the intermediate host of Schistosoma haematobium, was used as the antigen in haemagglutination tests in a survey of the prevalence of anti-snail antibodies in various population groups. It was found that sera from known bilharzia-infected individuals and randomly selected individuals from bilharzia endemic areas had significantly higher incidences as well as higher titres of antibodies to this snail antigen than non-infected individuals and individuals from non-endemic areas.

Adult↗
PubMed1976

Intermediate host antigens associated with the cercariae of Schistosoma haematobium.

Bulinus (Physopsis) africanus antigens were shown to be associated with the cercarial glycocalyx of Schistosoma haematobium using immunofluorescence and the Cercarienhüllen Reaktion. It is proposed that this snail antigen may sensitise the definitive host and that resistance to further invasion by cercariae could be induced in this manner.

Animals↗