In vitro erythrocytic membrane effects of dibenzyl trisulfide, a secondary metabolite of Petiveria alliacea.

We investigated the in vitro effect of dibenzyl trisulfide (DTS), a secondary metabolite of Petiveria alliacea, on erythrocyte elasticity, relaxation time and membrane morphology. Blood samples from 8 volunteers with hemoglobin AA were exposed to 100, 200, 400, 800 and 1000 ng/ml of DTS respectively and the elasticity and relaxation time measured. There were statistically significant, dose-dependent increases in elasticity and relaxation times. The changes in membrane morphology observed also increased with increased concentration of DTS. This suggests that DTS interaction with membrane protein resulted in increased elasticity, relaxation time and deformation of the erythrocyte membrane.

Can we influence medical students' approaches to learning?

Students use three approaches to learning and studying: deep, surface and strategic. These are influenced by the learning environment. In response to the General Medical Council's report 'Tomorrow's Doctors', the second year of the medical course at the University of Edinburgh was changed to promote deep learning, with learning objectives constructed according to the SOLO taxonomy, learning methods such as problem-based learning and constructively aligned written assignments and examinations. The Approaches to Study Skills Inventory for Students (ASSIST) was used to evaluate the effect of these changes. Scores were highest for deep approaches and lowest for surface approaches and showed almost no change during the course. There are various possible explanations. The students already scored highly on deep approaches at the beginning of Year 2 and it may be difficult to increase the deep scores further, particularly over the relatively short period of the study. Alternatively, the effect of the changes in learning environment may not be strong enough to change entrenched approaches which have hitherto been successful.

Medical student appraisal of interactive computer-assisted learning programs embedded in a general pathology course.

Computer-assisted learning programs (CALs) were embedded in a course on general pathology for medical students at the University of Edinburgh Medical School. Students' reactions to the programs were evaluated. Students completed written questionnaires and were interviewed and observed as they used the CALs. Students liked the CALs and felt that they were integrated with other parts of their teaching and aided them in understanding the subject material. Different question styles were variably appreciated. The most useful aspects of the CALs were the interactive parts (questions and answers), summaries, pictures, learning at the individual's own pace, and question practice, especially with MCQs. Students found the CALs an effective learning tool, particularly when linked with other course components as a complement to, rather than a replacement for, other learning methods.

Effect of using templates on the information included in histopathology reports on specimens of uterine cervix taken by loop excision of the transformation zone.

AIM: To determine the change in information relayed from histopathologists to clinicians by using templates for reporting specimens of uterine cervix sampled by loop excision of the transformation zone (LETZ). METHODS: Minimum datasets for the information required from LETZ specimens received from the colposcopy clinic, Royal Infirmary, Edinburgh, were incorporated into templates on the clinical service computer (Pinnacle) of the pathology department, University of Edinburgh. Pathologists completed hard copy versions, which were transcribed into the computer templates for report generation. The effect of the changes on the quality of the pathology reports was studied. The number of cases in which each item in the dataset received comment in template generated reports was compared with that in traditional prose reports compiled before the use of the templates and in prose reports issued after the introduction of the templates. Questionnaire studies were undertaken of clinicians' and pathologists' opinions of the template reports. RESULTS: In the template reports nearly all items received comment in almost 100% of cases. In the prose reports issued both before and after the templates were in use, most items were mentioned in a significantly lower proportion of cases. Clinicians thought the template reports were clearer and the information could be more readily assimilated than from the prose versions. CONCLUSIONS: The use of template reports in these types of specimen allowed more consistent and detailed information transfer. The change appeared to result from the use of the templates rather than from increased awareness of the items to be reported.

Role of epidermal growth factor and transforming growth factor alpha in the developing stomach.

AIMS: To determine whether epidermal growth factor (EGF) or the related transforming growth factor alpha (TGF alpha) may have a role in the developing human stomach; to substantiate the presence of EGF in human liquor in the non-stressed infant and whether EGF in amniotic fluid is maternally or fetally derived. METHODS: The temporal expression and localisation of EGF, TGF alpha, and their receptors during fetal and neonatal life were examined in 20 fetal and five infant stomachs. Simultaneously, samples of amniotic fluid and fetal urine from 10 newborn infants were collected and assayed for EGF by radioimmunoassay. RESULTS: EGF immunoreactivity was not noted in any of the specimens examined. In contrast, TGF alpha immunoreactivity was shown in mucous cells from 18 weeks of gestation onwards. EGF receptor immunoreactivity was seen on superficial mucous cells in gastric mucosa from 18 weeks of gestation onwards. The median concentration of EGF was 30 and 8.5 pg/ml in amniotic fluid and fetal urine, respectively, suggesting that EGF is not produced by the fetus. CONCLUSIONS: This study adds weight to the hypothesis that swallowed EGF, probably produced by the amniotic membranes, and locally produced TGF alpha, may have a role in the growth and maturation of the human stomach.

Scanning electron microscopy of the jejunum in children with protein-energy malnutrition.

Samples of jejunum from seven children dying from severe oedematous malnutrition were fixed with intralumenal glutaraldehyde in combination with external immersion, using a rapid autopsy protocol. Selected areas were post-fixed in osmium tetroxide, dehydrated with an ethanol series and critical point dried. After mounting on aluminium stubs, specimens were sputter-coated with a thin layer of gold and palladium. Scanning electron microscopy showed patterns ranging from subtotal villous atrophy, through partial villous atrophy with low ridges, to longer, taller ridges with cerebriform convolutions. In one case, villous height had been interpreted as normal on light microscopy. The scanning electron microscope revealed that the mucosa in this case was composed of ridges and leaf forms. Processing for scanning electron microscopy is simple. The specimens can be viewed and photographed in a relatively short time. In addition, the three-dimensional record provides clarification of ambiguities which often arise from routine histological sections.

Scanning electron microscopy of the jejunum in children with protein-energy malnutrition

Samples of jejunum from seven children dying from severe oedematous malnutrition were fixed with intralumenal glutaraldehyde in combination with external immersion, using a rapid autopsy protocol. Selected areas were post-fixed in osmium tetroxide, dehydrated with an ethanol series and critical point dried. After mounting on aluminium stubs, specimens were sputter-coated with a thin layer of gold and palladium. Scanning electron microscopy showed patterns ranging from subtotal villous atrophy, through partial villous atrophy with low ridges, to longer, taller ridges with cerebriform convolutions. In one case, villous height had been interpreted as normal on light microscopy. The scanning electron microscope revealed that the mucosa in this case was composed of ridges and leaf forms. Processing for scanning electron microscopy is simple. The specimens can be viewed and photographed in a relatively short time. In addition, the three-dimensional record provides clarification of ambiguities which often arise from routine histological sections. (AU)

Scanning electron microscopy of the jejunum in children with protein-energy malnutrition

Samples of jejunum from seven children dying from severe oedematous malnutrition were fixed with intralumenal glutaraldehyde in combination with external immersion, using a rapid autopsy protocol. Selected areas were post-fixed in osmium tetroxide, dehydrated with an ethanol series and critical point dried. After mounting on aluminium stubs, specimens were sputter-coated with a thin layer of gold and palladium. Scanning electron microscopy showed patterns ranging from subtotal villous atrophy, through partial villous atrophy with low ridges, to longer, taller ridges with cerebriform convolutions. In one case, villous height had been interpreted as normal on light microscopy. The scanning electron microscope revealed that the mucosa in this case was composed of ridges and leaf forms. Processing for scanning electron microscopy is simple. The specimens can be viewed and photographed in a relatively short time. In addition, the three-dimensional record provides clarification of ambiguities which often arise from routine histological sections.

Electron microscopy in Jamaica: applications and techniques.

Although the electron microscope was developed about 60 years ago in Germany, its arrival and subsequent use in Jamaica are of considerably more recent date. In this paper, the principles of scanning and transmission electron microscopy (SEM & TEM) are briefly explained, and examples are given of the research done with the electron microscopes at the University of the West Indies (UWI), Mona Campus, Jamaica, especially over the last three years. Detailed descriptions of specimen preparation are provided for both SEM and TEM and particular emphasis is placed on the methodology used in our laboratory, as it sometimes differs from the routine followed in electron microscopy units of temperate countries.

Electron microscopy in Jamaica: applications and techniques

Although the electron microscope was developed about 60 years ago in Germany, its arrival and subsequent use in Jamaica are of considerably more recent date. In this paper, the principles of scanning and transmission electron microscopy (SEM & TEM) are briefly explained, and examples are given of the research done with the electron microscopes at the University of the West Indies (UWI), Mona Campus, Jamaica, especially over the last three years. Detailed descriptions of specimen preparation are provided for both SEM and TEM and particular emphasis is placed on the methodology used in our laboratory, as it sometimes differs from the routine followed in electron microscopy units of temperate countries. (AU)

Electron microscopy in Jamaica: applications and techniques

Although the electron microscope was developed about 60 years ago in Germany, its arrival and subsequent use in Jamaica are of considerably more recent date. In this paper, the principles of scanning and transmission electron microscopy (SEM & TEM) are briefly explained, and examples are given of the research done with the electron microscopes at the University of the West Indies (UWI), Mona Campus, Jamaica, especially over the last three years. Detailed descriptions of specimen preparation are provided for both SEM and TEM and particular emphasis is placed on the methodology used in our laboratory, as it sometimes differs from the routine followed in electron microscopy units of temperate countries.

Cutaneous T-cell lymphoma presenting as papuloerythroderma--a case and review of the literature.

Papuloerythroderma has been described as a distinct clinical entity. It is characterized by pruritus, red flat-topped papules with skin crease sparing, blood eosinophilia and lymphopenia. It has been described almost exclusively in elderly men. We report a case of cutaneous T-cell lymphoma which, at presentation, was indistinguishable from papuloerythroderma, in a 79-year-old male. An excellent clinical response to low dose oral corticosteroids and photochemotherapy was observed. There have only been two previous reports linking papuloerythroderma with T-cell lymphoma. This patient is in keeping with the two previously reported cases and would support the view that papuloerythroderma may predispose to, or in fact represent, an early form of cutaneous T-cell lymphoma.

Mast cell density and PGP 9.5-immunostained nerves in angioleiomyoma: their relationship to painful symptoms.

Angioleiomyoma is frequently painful and the cause of the pain is unknown. The purpose of this study was to compare the mast cell population and innervation of painful and painless angioleiomyomas. Twenty-four cases of angioleiomyoma were examined; 16 painful and 8 painless cases. Pinacyanol erythrosinate and antibodies to protein gene product (PGP) 9.5 were used to demonstrate mast cells and nerves respectively. PGP 9.5-immunoreactive nerve fibres were found in most of the painful (13/16 cases) and painless lesions (5/8). Mast cells were not seen in half of the painful lesions but were seen in most of the painless lesions (7/8). The median mast cell density was 1.1 cells/mm2 for the painful lesions and 21.9 cells/mm2 for the painless lesions (P = 0.048, Mann-Whitney test). The lower mast cell density in the painful lesions may reflect increased mast cell degranulation. It is proposed that neural and vascular events, similar to those occurring in the triple response to mild cutaneous injury, may produce pain in angioleiomyoma and other painful skin tumours.

Combined proliferating cell nuclear antigen and morphometric analysis in the diagnosis of cutaneous lymphoid infiltrates.

AIMS: To evaluate the use of morphometry in the diagnosis of benign and malignant cutaneous lymphoid infiltrates; and to determine whether the sensitivity of detection of cutaneous T cell lymphoma (CTCL) could be improved by selectively measuring cells expressing proliferating cell nuclear antigen (PCNA). METHODS: 44 archival biopsy specimens were studied. These included cases of CTCL, non-specific chronic dermatitis, lichen planus and lupus erythematosus. PCNA was identified using a standard immunohistological technique. Reactive cells were identified using automatic colour discrimination, and the size and shape were determined interactively. Similar measurements were made on the total dermal lymphocyte population. RESULTS: There was no significant difference between the proportions of PCNA reactive cells in any of the diseases studied. The PCNA positive lymphocytes in CTCL were larger than those in lupus erythematosus and lichen planus and were more irregular in shape than those in chronic dermatitis. Differences were also seen in the total lymphocyte population. Plotting cell size and shape(fcircle) for PCNA cells together allowed CTCL to be differentiated from the inflammatory disorders with a sensitivity of 80% and a specificity of 93%. This was better than could be achieved using measurements made on the total cell population. CONCLUSIONS: This technique can be partly automated and could be useful in the differential diagnosis of cutaneous lymphoid infiltrates. The result are also of some interest in the further understanding of patterns of cell proliferation in skin associated lymphoid tissue.

Cephalic structures in the nemertine Parborlasia corrugatus-Are they really eyes?

The opinion as to whether tiny, approximately 0.1 mm large spots around the innermost margin of the cephalic slits in the Antarctic nemertine worm Parborlasia corrugatus represent photoreceptors or not has fluctuated over the years. This first electron microscope study of the enigmatic spots fails to detect any screening pigment granules, rhabdomeres, or lamellae, but reveals that the structure in question is principally made up of two types of cell, characterized by vesicular and vacuolar material of approximately 80 nm and 0.3 mum in diameter, respectively. Filamentous connective tissue strands with gaps for axons surrounds the 'eye-spot' and it is suggested that either exposure to the bright Antarctic summer light has led to a total disintegration of all visual membranes or these structures do not represent eyes at all.

Diagnosis of the acute ischaemic heart by ion elution from myocardium.

The post-mortem diagnosis of acute myocardial ischaemia may be difficult to establish in the absence of morphological changes in the myocardium or recent coronary thrombosis. Ischaemic cell injury leads to potassium (K) efflux and sodium (Na) influx and, if the blood is still circulating, the K:Na ratio of the tissue falls. In this study, the K:Na ratio was measured by eluting the ions from samples of myocardium and assaying the eluate. The method yields similar results to those obtained by a previous method, in which myocardial samples were homogenized. The K:Na ratios on samples of horizontal slices through the heart were plotted on maps of the slices. A low K:Na ratio corresponded to, but extended beyond, areas where there was morphological evidence of ischaemia. The method is simple and may be of use in routine practice.

Immunohistochemical and other features of breast carcinomas presenting clinically compared with those detected by cancer screening.

Features of 111 mammary carcinomas derived from breast cancer screening were compared with those of 69 carcinomas presenting 'clinically'. Screen detected cancers were smaller, had less likelihood of nodal metastases, included a higher proportion of in situ tumours and if invasive, tended to be of lower grade. Using immunohistochemical methods, the expression of c-erbB-2 oncoprotein, epidermal growth factor receptor (EGFR) and cathepsin D were compared in the two groups. A similar proportion of screened and unscreened tumours expressed c-erbB-2 oncoprotein and EGFR but expression of the oestrogen regulated protein cathepsin D was significantly more frequent in the screened group (P less than 0.05). Although a relatively small series, the results suggest a biological difference between 'screened' and 'clinical' tumours.