PubMed HealthSearch

Biomedical subjects

A E Simjee

Publications and source records attributed to A E Simjee.

At least 55 records · Page 3Linked to original sources

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

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

Serial ultrasound in amoebic liver abscess.

Serial ultrasound examinations were conducted in 93 patients with amoebic liver abscess. The initial size of the abscesses ranged from 3 to 17 cm. The time taken for complete healing to occur varied from 10 to 300 days and correlated directly with the initial size of the abscess cavity. As healing progressed, the abscess cavity became increasingly hypoechoic and assumed a smoother margin. In uncomplicated cases, complete healing occurred and, on ultrasound, no residual lesions were seen in the liver. There were two cases each of delayed healing and recurrence of amoebic liver abscess and the value of ultrasound in these situations is discussed. Ultrasound examination of the liver appears to be very suitable for assessing satisfactory progress of healing in amoebic liver abscess.

Humans

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

The iron status of Black subjects with amoebiasis.

Hepatic iron concentrations were measured in 60 Black patients who had died of amoebiasis. There were 18 infants and young children, 30 adult males and 12 adult females. The mean hepatic iron concentration in infants was normal (0,11% dry weight), while those in adult males and females were significantly raised (0,64% and 0,30% dry weight respectively). The figures for adults are somewhat higher than those previously found in Black subjects, suggesting that iron overload is more common in patients with amoebiasis than in the general population. The relevance of these findings to the pathogenesis of amoebiasis is not clear but the relationship may well not be a direct one, since hepatic iron stores were no larger in patients with liver abscesses than in subjects without.

Adult

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

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

Clinical presentation and biochemical abnormalities in black (Zulu) patients with cirrhosis in Durban.

A retrospective was designed to analyse the mode of presentation, clinical signs and haematological and biochemical abnormalities in 225 consecutive Black (Zulu) patients who were admitted to a general medical ward between the years 1970 and 1981 and in whom cirrhosis was later diagnosed. The most common presenting complaint was swelling of the body (60% of the patients), followed by abdominal pain (32%) and episodes of bleeding, mainly from the gastrointestinal tract (19%). On examination, hepatomegaly was encountered in 66% of the patients, with moderate to massive enlargement in 40%. Ascites was detected in 56%, with tense abdominal distension in 34%. Jaundice was present in 38% and emaciation, mental disturbance and splenomegaly in over 25%. Spider naevi (found in 2 patients) and Dupuytren's contracture (found in 1) were very rare. Thrombocytopenia and a high ESR were common. Over 90% of patients had low albumin and high globulin concentrations (albumin less than 20 g/dl and globulin greater than 60 g/dl in 25%). Bilirubin and alkaline phosphatase levels and the prothrombin index were found to be within normal limits in 32%, 24% and 52% of cases respectively. Histologically the lesion was most commonly micronodular (73%) with variable deposits of fat and iron. Peritoneoscopy was the most useful special investigation in the diagnosis of cirrhosis, leading to a correct diagnosis in 77% of cases. In conclusion, the clinical signs, biochemical abnormalities and histological features suggest that the factors causing cirrhosis in the community studied are mixed; it may result from the combined effects of alcohol abuse, malnutrition and chronic viral (e.g. hepatitis B) infections.

Abdomen

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

Peritoneoscopy in the diagnosis of tuberculous peritonitis.

Seventy-four patients with tuberculous peritonitis were examined by peritoneoscopy (laparoscopy). The characteristic features were uniform miliary tubercles studding the visceral and parietal peritoneum together with numerous adhesions between bowel loops, liver capsule, and abdominal walls. Guided biopsy yielded a definitive diagnosis in 56 cases. Special precautions are urged to avoid an increased risk of complications by peritoneoscopy and biopsy in tuberculous peritonitis.

Humans

Experiences with grey scale ultrasonography in hepatic amoebiasis.

Ultrasound examination was conducted in 151 proven cases of amoebic liver abscess. In the majority of patients the lesion was solitary but 25% of patients had multiple lesions; 17% of all the abscesses were in the left lobe of the liver. Most abscesses had no, or very few internal echoes and these were either of the same density as the normal liver (15%) or less dense (84%). In all cases there were relatively fewer echoes in the lesion. Abscesses in critical areas were accurately located especially in relation to the pericardium. Other liver lesions such as hepatoma which may enter into the clinical diagnosis can be recognised. Ultrasound has particular value in accurate localisation of the lesion for aspiration, demonstration of unsuspected multiple abscesses and size estimation in serial studies of the patient under treatment. The diagnostic errors were mainly due to initial inexperience and demonstrated some of the diagnostic pitfalls. It is concluded that the introduction of this technique has proved to be of considerable value in the diagnosis and management of amoebic liver abscess in our area, where the disease is still a major clinical entity. If diagnosed early and treated adequately the condition has an excellent prognosis.

Biopsy, Needle

Cryptococcal meningitis: our experience in 24 black patients.

The records of 24 patients with cryptococcal meningitis, admitted to King Edward VIII Hospital in Durban, were reviewed. There were 21 adults and 3 children over periods of 10 and 18 years, respectively. Slightly more males were affected. The age distribution was fairly even. The common clinical presentations were headache, neck stiffness, mental changes, cranial nerve palsies and papilloedema. The diagnosis was proved by the presense of Cryptococcus neoformans in the cerebrospinal fluid (CSF) in 21 of the patients, and in pathological tissue in the remaining 3 patients. A significant percentage of patients presented with an initial polymorphonuclear leucocyte predominance in the CSF. The other CSF findings were elevated protein and low sugar levels. Tuberculosis was the common coexisting disease. We found the mortality rate of 58% to be very high and a significant number of patients died even after adequate treatment with amphotericin B either singly or in combination with 5-fluorocytosine.

Adolescent

Antibodies to Escherichia coli in chronic liver diseases.

Patients with chronic active hepatitis or alcoholic cirrhosis have serum antibodies to many more serotypes of Escherichia coli than do patients with primary biliary cirrhosis or cryptogenic cirrhosis, or normal controls. They also have antibodies against more serotypes than cirrhotic patients with a portacaval shunt. These observations suggest that factors other than shunting of blood away from the liver are responsible for the increased range of antibodies. These factors are discussed. There was no correlation between the number of serotypes to which antibodies were present and the serum immunoglobulin concentration. In three patients, each with chronic active hepatitis, the antibodies were predominantly of the IgM class, while the elevation of globulin in general was mainly due to increased IgG and IgA levels. Antibodies to Escherichia coli, therefore, probably contribute only a small part of the increased globulin levels found in patients with chronic liver disease.

Adolescent