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Biomedical subjects

S Whitehead

Publications and source records attributed to S Whitehead.

11 recordsLinked to original sources
PubMed1990

Stage-dependent effect of deferoxamine on growth of Plasmodium falciparum in vitro.

Deferoxamine (DF) has antimalarial activity that can be demonstrated in vitro and in vivo. This study is designed to examine the speed of onset and stage dependency of growth inhibition by DF and to determine whether its antimalarial activity is cytostatic or cytocidal. Growth inhibition was assessed by suppression of hypoxanthine incorporation and differences in morphologic appearance between treated and control parasites. Using synchronized in vitro cultures of Plasmodium falciparum, growth inhibition by DF was detected within a single parasite cycle. Ring and nonpigmented trophozoite stages were sensitive to the inhibitory effect of DF but cytostatic antimalarial activity was suggested by evidence of parasite recovery in later cycles. However, profound growth inhibition, with no evidence of subsequent recovery, occurred when pigmented trophozoites and early schizonts were exposed to DF. At this stage in parasite development, the activity of DF was cytocidal and furthermore, the critical period of exposure may be as short as 6 hours. These observations suggest that iron chelators may have a role in the treatment of clinical malaria.

Animals↗
PubMed1987

Not tarsal tunnel syndrome: a malignant "Triton" tumour of the tibial nerve.

A 23 year old male patient presented with a venous thrombosis in the right calf. This was followed by symptoms, signs and electromyographic findings suggestive of a tarsal tunnel syndrome. Symptoms were briefly relieved by surgical division of the flexor retinaculum. Subsequently, patient developed swelling in the calf and was found to have a malignant ("Triton") tumour of the tibial nerve and required above knee amputation. In the absence of obvious foot or ankle deformity, caution should be exercised in making the diagnosis of tarsal tunnel syndrome.

Adult↗
PubMed1986

Pure red cell aplasia and thymoma: demonstration of persisting inhibition of erythropoiesis after thymectomy and resolution after immune suppressive treatment.

A 61 year-old woman presented with general malaise, hair loss, pure red cell aplasia (PRCA) and thymoma: no growth of erythropoietic colonies in vitro (BFU-E) was observed in the presence of her own serum. The thymoma was removed: after the operation no improvement of her anaemic condition was observed and colony growth was very poor, although T-depleted narrow preparations showed a modest BFU-E formation in autologous serum. Following treatment with azathioprine, a complete recovery was seen, associated with normal BFU-E formation in vitro. This observation suggests that a complex inhibition of erythropoiesis may operate in PRCA involving both humoral and cellular factors; thymectomy alone may not be sufficient to restore haemopoiesis, but has to be followed by immune suppressive treatment.

Antibody Formation↗
PubMed1977

Abnormalities of the local immune system in intestinal neoplasia: a morphological study.

In colonic adenocarcinomata abnormalities have been noted in all morphological aspects of the local immune system of the bowel; thus, in such tumours there is a defective production of secretory IgA, a diminished content of secretory component (SC) and a marked decrease in intraepithelial lymphocytes. By contrast, no such abnormalities were noted in the non-neoplastic areas of the bowel, either immediately adjacent to, or some distance from, the carcinoma. These findings suggest that there is not usually any generalised morphological abnormality of the local immune systems in intestinal neoplasia and that the immunological abnormalities noted within the tumour are a result of the changed nature of the epithelium, thus altering, or interfering with, the normal interactions between epithelial and lymphoid tissue in the gut.

Adenocarcinoma↗