The basis of tear ferning

Fern-like crystallisation occurs in many body fluids when sampled and dried, including the tears. Tear ferning has been proposed as a diagnostic test of keratoconjunctivitis sicca (KCS), but the mechanism of reduced ferning in the dry eye is poorly understood. By microscopic examination of tear ferns and review of gynaecological and crystallographic literature, we seek an explanation for the reduced tear ferning in KCS. The physico-chemical variables controlling the crystal ‘habit’ (viscosity, osmolality, protein content, and mucous quality or quantity) are examined to ascertain which might be responsible for the decreased ferning of dry eye tear samples. We hypothesise that a shift in the salt-to-macromolecule ratio, increased lipid contamination of mucus and altered tear rheology are the features of dry eye which best explain the altered ferning patterns in this condition.     

Neonatal striatal grafts prevent lethal syndrome produced by bilateral intrastriatal injection of kainic acid

It is reported that unilateral grafts of neonatal striatal tissue protect the recipient from the lethal aphagia and adipsia produced by bilateral intrastriatal injection of 10 nmol of kainic acid in rats. It is shown that neither adult striatum nor neonatal tissue from other sites have the same lifesaving effect and that the salutary effect of the graft is dependent upon graft survival. Grafts from a histoincompatible donor are apparently rejected, leading to the death of the recipient. Cyclosporine inhibits rejection thereby enabling recipient survival. It is postulated that the graft exerts a neurohumoral influence that protects the striatum from the toxic effect of kainate.     

A retrograde fluorescent-labeling study of direct relationship between the limbic (anterodorsal and anteroventral thalamic nuclei) and the visual system in the albino rat

Injecting different fluorescent tracers into the right anterodorsal (AD)/anteroventral (AV) or AD/AV and the primary visual nuclei of dorsal lateral geniculate (dLGN) or superior colliculus (SC), a direct projection from the left retina to these anterior thalamic nuclei was ascertained in the central part of ventro-nasal retinal quadrant. Single-labeled cells were of small type. No double-labeled cells were demonstrated.     

Herpes simplex virus and human papillomavirus infection in cervical disease in Argentine women.

The aim of the present study was to determine that prevalence of herpes simplex virus (HSV) type 1 and 2 in cervical samples from Argentine women and to assess the role of HSV-2 in cervical cancer. A sample of 79 normal and 200 neoplastic cervical tissues (35 invasive cervical carcinomas, 75 high-grade squamous intraepithelial lesions, 79 low-grade squamous intraepithelial lesions and 11 abnormal squamous cells of undermined significance) was analyzed for herpes simplex and human papillomavirus DNA using the polymerase chain reaction method. Viral genotyping was performed by single strand conformation polymorphisms and restriction fragment length polymorphisms. The overall prevalence of HSV was 21.5% in controls and 29% in cases. Among women with normal cytology, herpes simplex prevalence in HPV positive (20.8%) women was approximately the same as in negative (21.8%) women. HPV- and age- adjusted ORs of high-grade squamous intraepithelial lesions and invasive cervical carcinomas for HSV-2 were 1.4 (p = 0.6) and 1.6 (p = 0.5), respectively. The obtained results indicated that herpes simplex virus may not be involved in cervical cancer development. Future investigations are needed to provided conclusive evidence on the role of this pathogen in cervical cancer.     

Dietitians' role in decisions to withhold nutrition and hydration

Decisions to limit nutrition and hydration in irreversibly or terminally ill patients are becoming more frequent in both hospitals and home-care settings. Although clear-cut principles or rules are not always possible, appropriate decisions about any form of life-sustaining treatment, nutrition and hydration included, require conducting a productive moral conversation within the medical management team and/or the institutional ethics committee. In this article, we discuss how dietitians can participate in these medical decisions.