Ion and water distribution in pig lenses incubated at 0 degree C to disable ion transport pumps.

This study was designed to test how extended exposure of lenses to sera with different ionic strengths influences the distribution of ions and water in the lens. Pig lenses were incubated in cold sera (0 degree C), which were adjusted to variable concentrations of NaCl, and their K+, Na+, Cl-, and water contents were measured. Incubation at 0 degree C inhibits active transport processes and thereby allows equilibration of the mobile ions and water. The hypothesis was that lens water content (volume) would follow the ion-induced protein changes predicted by a model derived from previous osmotic studies on proteins. As expected, exposure of the lens to cold caused a gain of sodium and a partial loss of potassium. However, the potassium concentration in the lens remained several fold higher than that in the bathing solution (about 41 vs. 1.8-4.6 mM/kg H2O), indicating that a portion of the potassium within the cold-exposed lens was not free to diffuse. That the water content of the lens showed a negative rather than a positive relationship with the concentration of NaCl within the lens was explained by the idea that an increase in NaCl within the lens (up to at least 250 mM/kg H2O) causes a decrease in the osmotically unresponsive water volume associated with lens proteins.     

The potential value of CA125 as a tumour marker in small volume, non-evaluable epithelial ovarian cancer.

Seventy four consecutive patients with epithelial ovarian cancer have been followed up longitudinally with serial serum CA125 for up to 48 months. From this database, the CA125 changes in small volume disease have been evaluated. For long term complete responders (n = 12), the mean plateau level of CA125 was 7.2 U/ml (95% confidence interval; 5.6 to 9.2 U/ml). The natural half-life of CA125 at 5.1 days (range 3.8 to 7 days) was calculated from five patients with Stage I and II disease who underwent complete surgical excision. A mean lead time of 99 days (range 14 to 255 days) was demonstrated between marker detection of disease progression and clinically apparent progressive disease in 12 out of 13 patients (92%) who relapsed after chemotherapy induced complete remission. The threshold of tumour volume detection with CA125 is unlikely to be determined by an arbitrary cut-off level. The kinetics of CA125 provide more useful information and the potential to define complete response or indeed cure with CA125 parameters requires further investigation.     

Sexual health education interventions for young people: a methodological review.

OBJECTIVES--To locate reports of sexual health education interventions for young people, assess the methodological quality of evaluations, identify the subgroup with a methodologically sound design, and assess the evidence with respect to the effectiveness of different approaches to promoting young people''s sexual health. DESIGN--Survey of reports in English by means of electronic databases and hand searches for relevant studies conducted in the developed world since 1982. Papers were reviewed for eight methodological qualities. The evidence on effectiveness generated by studies meeting four core criteria was assessed. Judgments on effectiveness by reviewers and authors were compared. PAPERS--270 papers reporting sexual health interventions. MAIN OUTCOME MEASURE--The methodological quality of evaluations. RESULTS--73 reports of evaluations of sexual health interventions examining the effectiveness of these interventions in changing knowledge, attitudes, or behavioural outcomes were identified, of which 65 were separate outcome evaluations. Of these studies, 45 (69%) lacked random control groups, 44 (68%) failed to present preintervention and 38 (59%) postintervention data, and 26 (40%) omitted to discuss the relevance of loss of data caused by drop outs. Only 12 (18%) of the 65 outcome evaluations were judged to be methodologically sound. Academic reviewers were more likely than authors to judge studies as unclear because of design faults. Only two of the sound evaluations recorded interventions which were effective in showing an impact on young people''s sexual behaviour. CONCLUSIONS--The design of evaluations in sexual health intervention needs to be improved so that reliable evidence of the effectiveness of different approaches to promoting young people''s sexual health may be generated.     

Right atrial dilatation increases inositol-(1,4,5)trisphosphate accumulation. Implications for the control of atrial natriuretic peptide release

Stretching the right atrium of isolated perfused [3H]inositol-labelled rat hearts was shown to stimulate the phosphatidyl-inositol turnover pathway as demonstrated by the accumulation of [3H]inositol-(1,4,5)trisphosphate and its degradation products. Stimulation was detectable after 1 min with larger increases observed after 10 or 20 min. These findings demonstrate that the myocardium can respond to dilatation by an activation of the phosphatidylinositol turnover pathway. Such a mechanism has implications for the release of atrial natriuretic peptide following right atrial distention.