A systems approach to cardiovascular disease research

Research in cardiovascular disease is fragmented and difficulties arise in communication between workers in different disciplines. There is no shortage of facts but rather a deficiency in concepts which can accommodate the facts. Systems analysis is suggested as a way to develop a conceptual framework for the assimilation of existing and new information, and to give a basis for decisions about priorities in research. A model of mechanisms in cardiovascular disease is presented to illustrate the approach.

Acute spinal epidural hematoma secondary to aspirin-induced prolonged bleeding

A case of acute and spontaneous spinal epidural hemorrhage is described in which there was no history or evidence of trauma, conventional anticoagulant therapy, hemophilia or vascular anomalies. A recent history of excessive ingestion of an aspirin-containing medication was obtained and the clinical and laboratory picture of an aspirin-induced bleeding disorder was documented. We have discussed the mechanism and hematological considerations of the syndrome of aspirin induced bleeding.

Human fallopian tubes in organ culture: preparation, maintenance, and quantitation of damage by pathogenic microorganisms

An experimental organ culture model has been developed in which rates of damage to fallopian tube mucosa by agents of sexually transmitted diseases can be quantitated. This required assessment of the effect on organ cultures of such variables as the anatomic area of the fallopian tube employed, endocrinological status of the donor, and composition of media. Organ cultures established from the ampulla of tubes of nonpregnant, premenopausal women and maintained with Eagle minimal essential medium containing 0.05 M N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid buffer were most suitable for quantitative studies. Various means of quantitating damage to fallopian tube mucosa were evaluated. Of these, sequential estimations of ciliary vigor and percentage of the periphery of fallopian tube pieces with active cilia proved the most successful. To assess the specificity of the model, fallopian tube organ cultures were infected with Neisseria gonorrhoeae or N. pharyngis, a commensal Neisseria. Damage by N. gonorrhoeae was significantly greater than that by N. pharyngis at each period of observation (P less than 0.001), suggesting that, by using the model, differences in virulence can be determined in vitro that reflect differences in virulence for humans. This model is a potentially valuable tool for studying the interaction of human genital mucosa with known or suspected agents of sexually transmitted diseases.

An international haematological survey

Haematological surveys of adult population samples were conducted simultaneously in 12 countries, all but one of which are in Europe. Haematological estimations on samples from nine of the countries were made in one central laboratory. Differences between countries in the mean levels of haemoglobin (and haematocrit and red cell count) were found to be relatively small, and the prevalence of levels below the arbitrary WHO levels for anaemia were, on the whole, low. In males, the evidence suggests a fall in haemoglobin level throughout adult life, which increases slightly in advanced age. In females, there is no evidence of any important relationship between age and haemoglobin level.