Red tides in the Gulf of Mexico: Where, when, and why?

[1] Independent data from the Gulf of Mexico are used to develop and test the hypothesis that the same sequence of physical and ecological events each year allows the toxic dinoflagellate Karenia brevis to become dominant. A phosphorus-rich nutrient supply initiates phytoplankton succession, once deposition events of Saharan iron-rich dust allow Trichodesmium blooms to utilize ubiquitous dissolved nitrogen gas within otherwise nitrogen-poor sea water. They and the co-occurring K. brevis are positioned within the bottom Ekman layers, as a consequence of their similar diel vertical migration patterns on the middle shelf. Upon onshore upwelling of these near-bottom seed populations to CDOM-rich surface waters of coastal regions, light-inhibition of the small red tide of ~1 ug chl l(-1) of ichthytoxic K. brevis is alleviated. Thence, dead fish serve as a supplementary nutrient source, yielding large, self-shaded red tides of ~10 ug chl l(-1). The source of phosphorus is mainly of fossil origin off west Florida, where past nutrient additions from the eutrophied Lake Okeechobee had minimal impact. In contrast, the P-sources are of mainly anthropogenic origin off Texas, since both the nutrient loadings of Mississippi River and the spatial extent of the downstream red tides have increased over the last 100 years. During the past century and particularly within the last decade, previously cryptic Karenia spp. have caused toxic red tides in similar coastal habitats of other western boundary currents off Japan, China, New Zealand, Australia, and South Africa, downstream of the Gobi, Simpson, Great Western, and Kalahari Deserts, in a global response to both desertification and eutrophication.

Improved haemodynamic stability with administration of aprotinin during orthotopic liver transplantation.

In a placebo-controlled, double-blind study, we have investigated the hypothesis that patients for orthotopic liver transplantation (OLT) treated with high-dose aprotinin (serum concentrations > or = 200 kiu ml-1) show greater haemodynamic stability on graft reperfusion. We studied 55 adult patients presenting for OLT, and 52 were included in the analysis. The treatment and placebo groups were similar in patient characteristics. The anaesthetic regimen used was standardized, and veno-venous bypass were used in all patients. Cardiac output measurements and haemodynamic profiles were recorded at intervals throughout anaesthesia and surgery. Arterial and mixed venous oxygen saturations were measured by co-oximetry. Derived variables were measured using standard formulae. Aprotinin treated patients had greater values for systemic vascular resistance on reperfusion, with a lesser cardiac index and calculated oxygen delivery. Oxygen consumption, however, was significantly greater, despite reduced delivery.

Preliminary results of skin cancer screening in West Virginia.

Although skin cancer screening is theoretically of value, its effectiveness has not been firmly established because few studies have systematically followed persons with a positive screen to obtain pathologically confirmed diagnoses. From the 799 persons screened at Charleston Area Medical Center in 1988 and 1989, 153 screenees with suspected skin cancer, dysplastic nevi, and congenital nevi were followed to determine their final diagnosis. Follow-up was done by letter and telephone calls to both the individuals who screened positive and their treating physicians. Eighty-four (54 percent) then sought medical attention as a result of letters and calls. Thirty-one basal cell carcinomas, three squamous cell carcinomas, three dysplastic nevi, two melanomas, and one congenital nevus were pathologically confirmed. The predictive value positive of the screenings was 32 percent to 60 percent for non-melanoma skin cancer, 9 percent to 25 percent for dysplastic nevi, and 15 percent for melanoma. This study suggests that post-screening follow-up of those with suspected premalignant and malignant skin lesions is feasible and should be encouraged so that more definitive evaluation and treatment can potentially be performed and skin cancer screenings more accurately assessed.

Erythema gyratum repens with associated squamous cell carcinoma of the lung.

A 63-year-old man with erythema gyratum repens (EGR) was found to have an underlying squamous cell carcinoma of the lung. Neither radiation nor chemotherapy had any effect on the extensive eruption. EGR is the most distinctive of the figurate erythemas, and continues to be one of the most consistent cutaneous signs of an associated visceral malignancy.

Laser surgery for blue rubber bleb nevus.

A 21-year-old man has had extensive cutaneous and visceral manifestations of the blue rubber bleb nevus syndrome since birth. Surgical therapy with the carbon dioxide laser was successful in removing 225 skin hemangiomas without recurrences or complications such as hemorrhage and infection. The cosmetic and follow-up results have been excellent.