A comparative laboratory diagnosis of malaria: microscopy versus rapid diagnostic test kits

Objective

To compare the two methods of rapid diagnostic tests (RDTs) and microscopy in the diagnosis of malaria.

Methods

RDTs and microscopy were carried out to diagnose malaria. Percentage malaria parasitaemia was calculated on thin films and all non-acute cases of plasmodiasis with less than 0.001% malaria parasitaemia were regarded as negative. Results were simply presented as percentage positive of the total number of patients under study. The results of RDTs were compared to those of microscopy while those of RDTs based on antigen were compared to those of RDTs based on antibody. Patients'' follow-up was made for all cases.

Results

All the 200 patients under present study tested positive to RDTs based on malaria antibodies (serum) method (100%). 128 out of 200 tested positive to RDTs based on malaria antigen (whole blood) method (64%), while 118 out of 200 patients under present study tested positive to visual microscopy of Lieshman and diluted Giemsa (59%). All patients that tested positive to microscopy also tested positive to RDTs based on antigen. All patients on the second day of follow-up were non-febrile and had antimalaria drugs.

Conclusions

We conclude based on the present study that the RDTs based on malaria antigen (whole blood) method is as specific as the traditional microscopy and even appears more sensitive than microscopy. The RDTs based on antibody (serum) method is unspecific thus it should not be encouraged. It is most likely that Africa being an endemic region, formation of certain levels of malaria antibody may not be uncommon. The present study also supports the opinion that a good number of febrile cases is not due to malaria. We support WHO''s report on cost effectiveness of RDTs but, recommend that only the antigen based method should possibly, be adopted in Africa and other malaria endemic regions of the world.     

BIOLOGIC CHARACTERISTICS OF CULTURED HUMAN VITILIGO MELANOCYTES

Background. Vitiligo is a pigmentary disorder of unknown cause characterized by depigmented patches due to destruction of melanocytes. Recently, the inherent cellular defect theory has been discussed. To investigate the biologic characteristics of cultured melanocytes from normal and vitiligo subjects, this study had the purpose to examine the functional and ultrastructural characteristics of these melanocytes and to observe the morphologic and functional changes of melanocytes in response to ultraviolet B irradiation. Methods. Melanocytes were isolated and cultured from foreskin and arm skin of normal and vitiligo subjects. The DNA synthesis, tyrosinase activity assay, transmission and scanning electron microscopic examination, and the effects of ultraviolet B(uvB)-irradiation on cultured melanocytes were studied. Results. Vitiligo melanocytes showed no significant differences in DNA synthesis and tyrosinase activity compared with normal melanocytes, but the vitiligo melanocytes contained dilated and/or circular rough endoplasmic reticulum (RER) on transmission electron microscopic examination. Exposure of the cultured melanocytes to UVB resulted in increased protein synthesis and tyrosinase activity. Morphologic alterations and changes in DNA synthesis were also noted. Compared with normal melanocytes, the responses of vitiligo melanocyte to UVB showed no significant difference. Conclusions. Normal and vitiligo melanocytes showed similar biologic characteristics except in the changes of RERS in the vitiligo melanocytes. The ultrastructural aberrations in vitiligo subjects do not seem to be directly related to the biologic characteristics and the responses to UVB irradiation in vitiligo melanocytes.     

PERIPHERAL BLOOD LYMPHOCYTE IMBALANCE IN KOREANS WITH ACTIVE VITILIGO

Background. An immune-mediated destruction of melanocytes is the most popular current theory of vitiligo. There have been a few published reports on the assessment of lymphocyte population in vitiligo, and they showed mixed results. The purpose of our investigation was to assess peripheral lymphocyte subpopulations in Koreans with actively spreading vitiligo. Methods. Fifty patients with actively spreading vitiligo and 30 normal persons were studied for peripheral blood lymphocyte imbalance using flow cytometry. The percentages of total T-lymphocytes, B-lymphocytes, helper T cells, suppressor T cells, and natural killer cells were evaluated with the use of CD3, CD19, CD4, CD8, and CD16 monoclonal antibodies, respectively. Results. The mean value of helper T cells showed a significant difference between the two groups with the value being 38.2% in patients and 43.5% in control subjects. Seventeen of the 50 patients showed reversed helper/suppressor T cell ratio, whereas only 1 of 30 control subjects showed reversed ratio. There was a statistically significant difference in the mean percentage of helper T cells and suppressor T cells between generalized vitiligo patients and control subjects. The percentage of B cells in patients with recent onset less than 1 year was higher than control subjects and patients with late onset. The mean percentage of natural killer cells was increased significantly in patients with negative autoantibody test. Conclusions. The present data show that immunologic abnormalities, both cellular and humoral, are involved in the pathogenesis of vitiligo.     

Attitudes towards new HIV biomedical prevention technologies among a cohort of HIV‐negative gay men in Sydney,Australia

Objectives

The aim of the study was to explore the awareness of rectal microbicides, the use of pre‐exposure prophylaxis (PREP) and the willingness to participate in biomedical HIV prevention trials in a cohort of HIV‐negative gay men.

Methods

In a community‐based cohort study, HIV‐negative homosexually active men in Sydney, Australia were questioned about awareness of rectal microbicides, use of PREP, and willingness to participate in trials of such products. Predictors of awareness and willingness to participate were analysed by logistic regression. Use of PREP was examined prospectively.

Results

Overall, 14% had heard of rectal microbicides. Older (P=0.05) and university‐educated men (P=0.001) were more likely to have knowledge of rectal microbicides. Almost one‐quarter (24%) of men reported that they were likely/very likely to participate in rectal microbicide trials. Among those men with definite opinions on participation, awareness of rectal microbicides was significantly associated with unwillingness to participate [odds ratio (OR) 0.78, 95% confidence interval (CI) 0.65–0.93, P=0.007]. Willingness to participate in trials using antiretroviral drugs (ARVs) to prevent HIV infection was reported by 43% of men, and was higher among those who reported unprotected anal intercourse (UAI) with HIV‐positive partners (OR 1.88, 95% CI 0.99–3.56). There was no evidence of current PREP use.

Conclusions

This study demonstrates that Australian gay men have had little experience with PREP use and rectal microbicides. About half would be willing to consider participation in trials using ARVs to prevent HIV infection. Extensive community education and consultation would be required before PREP or rectal microbicides could be trialled in populations of gay Australian men.

     

The Maastricht social participation profile: development and clinimetric properties in older adults with a chronic physical illness

Purpose  

To develop and test the Maastricht Social Participation Profile (MSPP), an instrument measuring the actual social participation by older adults with a chronic physical illness, in accordance with their own definition of social participation.     

A procedure for removing high titer antibodies by extracorporeal protein-A-sepharose adsorption in hemophilia: substitution therapy and surgery in a patient with hemophilia B and antibodies

A 37-yr-old hemophiliac with factor IX antibody in high titer required operation for a pseudotumor growing invasively into the bone in his left elbow. Exchange plasma-pheresis was not feasible, mainly because of possible stimulation of factor IX inhibitor. In addition, the patient had antibodies against tissue antigens. The factor IX antibodies were of IgG type and adsorbable to protein-A-agarose. The antibodies were removed by extracorporeal adsorption of the plasma (separated intermittently in a cell centrifuge) to sterile protein-A- Sepharose in columns, operated by a computer. The treated plasma was retransfused. In this manner, a total of 6000 ml of plasma was depleted of antibodies, and the antibody titer, as well as the total immunoglobulin content, decreased to one-fifth of the original values. The remaining antibodies were neutralized by infusion of factor IX concentrate. Conventional substitution therapy, in combination with immunosuppression, was then possible. The operation was performed without complications. No signs of hemolysis, complement activation, or activation of the coagulation system occurred. In principle, the same form of treatment can be used in patients with other forms of antibodies.     

Surgical Division of an Accessory Atrioventricular Connection in the Posterior Septal Region Following Ventricular Fibrillation in the Wolff-Parkinson-White Syndrome*

Summary: Surgical division of an accessory atrioventricular connection in the posterior septal region following ventricular fibrillation in; the Wolff-Parkinson-White syndrome. N. Sadick,;D. K. Baird and J. B. Uther, Aust. N.Z. J. Med., 1978, 8 , pp. 652–655. A young man presented with atrial fibrillation and a rapid ventricular response which degenerated into ventricular fibrillation. Electrophysiological study demonstrated an accessory atrioventricular connection in the posterior septal region. This was sectioned to prevent recurrence of his arrhythmia. Post-operative electrophysiological study demonstrated that the surgical section was successful.