Study on the possible role of heat shock proteins in host resistance to Trichinella spiralis infection in experimental animals

The expression of heat shock proteins (HSPs) and their immunogenic role in host parasite relationship has been studied in T. spiralis infection in mice. Two groups of infective stage larvae were incubated at 37 degrees C or at 43 degrees C for 3 hours in a nutrient medium. Crude somatic extracts and excretory/secretory (E/S) products were obtained. Quantitative estimation and in vitro translation of mRNA were carried out. Crude somatic extracts, E/S products and in vitro translated proteins were all subjected to SDS-PAGE and immunoelectrophoresis against a monoclonal antibody to HSP70. They were further used to immunize mice which were then infected with T. spiralis. The degree of immunization was assessed by counting adult worms, muscle larvae and estimating total gamma globulins of mice. SDS-PAGE revealed intense peaks of 71 KDa and 81 KDa in all proteins obtained from heat shocked larvae. These proteins have been proved to involve HSP70 as manifested by their strong reactivity with anti-HSP70. In vitro translated products of heat shocked larvae (at 43 degrees C) proved to be strongly immunogenic as evidenced by the lower adult worm, muscle larval counts and higher total gamma globulins in sera of mice in comparison with the control non immunized group as well as to other larval antigens incubated at 37 degrees C. So, exposure to heat, can induce the synthesis of heat shock proteins which can defend the organism against environmental stress. Meanwhile, these heat shock proteins can render the host more refractory to reinfection.

The role of Fas system [Fas-FasL] as an inducer of apoptosis in cutaneous leishmaniasis: a combined human and experimental study

Cutaneous leishmanial lesions as well as serum samples from both infected human and Swiss-albino mice were used to investigate the role of Fas system (Fas-FasL) as an inducer of apoptosis and other leishmanicidal cytokines in the disease development in cutaneous leishmaniasis. Soluble Fas was estimated by ELISA, other leishmanicidal cytokines were detected by PAP technique and tissue Fas by RT-PCR. Results showed a significant increase in interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha), nitric oxide (NO) and soluble Fas in both infected human and mice. As regards the tissue Fas, there was marked expression in human samples while in murine samples, the expression was reduced in chronic infected mice than in the late acute infected animals which can explain the progression of the lesion in the animals. This study confirms the role of Fas system as an inducer of apoptosis.

Morphometric and histochemical study of the adrenal cortex in experimental schistosomiasis mansoni

In this study, 45 mice were used, 30 mice of them were injected subcutaneously with 80-100 schistosoma mansoni cercariae and 15 mice remained uninfected and served as a control group. Infected mice were killed at 8 and 12 weeks post-infection while control mice were killed at one time. Paraffin sections were made from adrenal cortex and liver. The thickness and cellularity of zonae glomerulosa and fasciculata as well as the serum cortisol level were determined. In the infected group of mice, the zona glomerulosa and fasciculata increased in the thickness and cellularity and the serum cortisol level increased with the progression of infection as compared with the control uninfected group. Bilharzial liver granulomas were profound in the infected group at 12 weeks post-infection which coincided with the time of suprarenal hyperactivity.

The pathogenesis of arthropathy in experimental Schistosomiasis mansoni

The pathogenesis of arthropathy in experimental schistosomiasis mansoni was studied. 70 Swiss albino mice were used, 14 served as control while 56 were subcutaneously infected with 80-100 Schistosoma mansoni cercariae/mouse. Mice were sacrificed at 8, 10, 12, 14, 16, 18 and 20 weeks postinfection (p.i.). Shoulder and knee joints were taken and processed for H & E stain and immunoperoxidase stain. As regards histopathological examination, 75% of infected mice showed marked pathological joint changes, with no Schistosoma ova could be detected in all examined sections. These changes appeared at the 12th week (p.i) and became more severe with the chronicity of infection. Immunohistochemical examination of the infected joints, revealed 75% positivity of schistosomal antigen deposition with mild to moderate expression (in early and late stages of infection respectively). The detection of schistosomal antigen in joints of infected mice which coincided with the histopathological affection, can be considered as the aetiological agent in induction of schistosomal arthropathy. Hence, the term reactive schistosomal arthropathy can be changed into schistosomal arthritis.

Hypothalamic origin of reproductive failure in chronic experimental toxoplasmosis

Laboratory bred female mice were used to study the effect of chronic toxoplasmosis on reproductive performance. The animals were infected with small dose (3 x 10(3)) tachyzoites of Toxoplasma parasites. The female mice were mixed with normal males for one week, then separated to monitor their reproductive performance one and two months post infection (p.i). Mice bred one month p.i. showed reproductive failure with one of twenty females delivered two sick newborns. The others did not complete pregnancy and faetal wastage occurred. Mice bred two months p.i. were infertile. Histopathological examination of the ovaries revealed impaired folliculogenesis and atropic degeneration. Coronal sections of cerebrum showed widespread vasculitis, focal disruption of the ependymal cells lining both the lateral and third ventricles. The supraoptic and paraventricular hypothalamic nuclei were deformed and showed pyknotic neurons. Immunoperoxidase staining was used to detect IgG and IgM deposits in brain tissue. IgG deposits were found on the vicinity of Toxoplasma cysts and focally in the paraventricular zone. So, the reproductive failure of infected mice was due to hypogonadotrophic hypogonadism secondary to hypothalamic dysfunction as a result of chronic toxoplasmosis.

Lymphocyte subpopulations in the mammary gland of the goat

Mammary glands of pregnant, lactating and resting goats were studied by immunohistochemistry for lymphocyte subpopulations using a panel of monoclonal antibodies. All T lymphocyte subpopulations that may have a role in the immune response, CD2+, CD4+, CD8+ and gamma delta T cells and subsets, were present in the mammary gland and were noted to increase in number progressively during pregnancy, decrease significantly during lactation, and then moderately increase during the resting period. CD4+ cells, the predominant cell type in the mammary gland, were located mainly in the connective tissue, whereas CD2+, CD8+ and TcR1-N24+ cells were predominant in the intraepithelial areas. TcR1-N6+ cells were detected almost exclusively during pregnancy, being localized mainly in the connective tissue. Their proportion decreased markedly following parturition. Very few WC1-N3+ and -N4+ cells were detected in the mammary gland. It is suggested that the majority of gamma delta T lymphocytes in the mammary gland of the goat are CD2+ CD8+ WCl-, a distinctive subset from that of the WCl+ subset in peripheral blood.

Poliomyelitis in Malaysia: two confirmed cases after 6 years without polio

Poliomyelitis in Malaysia has not been reported since 1986. We report two cases of poliomyelitis in non-immunized children whose parents, though relatively educated, opted not to vaccinate their children for socio-cultural reasons. This recent trend may interfere with our attempts to eradicate poliomyelitis globally by the year 2000. The clinical features, pathophysiology and differential diagnosis are discussed.

Axillofemoral and femorofemoral grafts: a 6-year experience with emphasis on the relationship of peroperative flow measurement to graft survival

Over a 6-year period 64 axillofemoral bypass and femorofemoral crossover grafts have been performed in 58 patients, most of whom were considered unfit for intra-abdominal surgery. Indications were peripheral ischaemia in 78 per cent and disabling claudication in 22 per cent. The limb salvage rate at 3 years was 75 per cent. No claudicants lost limbs, but only one-third of patients presenting with forefoot gangrene or ulceration avoided amputation. Most patients presenting with ischaemic symptoms at rest had associated femoropopliteal and distal disease, confirmed by the ankle pressure index measurements, and this influenced graft patency. Although the cumulative patency at 3 years for all grafts combined was 57 per cent with similar patencies for both the axillofemoral and femorofemoral grafts, early occlusion was more common in axillofemoral grafts and this may be reduced in bifemoral grafts by the increased flow rate in the vertical limbs. Peroperative electromagnetic flowmeter measurements were made after reconstruction on 55 femoral arteries in 46 of the patients and graft flow velocities were derived from these measurements. Comparison between velocities from those grafts remaining patent and those subsequently occluding showed a high incidence of occlusion in grafts with a maximal velocity after distal vasodilatation of less than 8 cm/s. Graft occlusion after the first postoperative month was more commonly associated with other factors such as continued smoking, severity of distal disease and perigraft infection.