Effects of crocetin on pulmonary gas exchange in foxhounds during hypoxic exercise.

The carotenoid compound crocetin has been hypothesized to enhance the diffusion of O(2) through plasma, and observations in the rat and rabbit have revealed improvement in arterial PO(2) when crocetin is given. To determine whether crocetin enhances diffusion of O(2) between alveolar gas and the red blood cell in the pulmonary capillary in vivo, five foxhounds, two previously subjected to sham and three to actual lobectomy or pneumonectomy, were studied while breathing 14% O(2) at rest and during moderate and heavy exercise before and within 10 min after injection of a single dose of crocetin as the trans isomer of sodium crocetinate (TSC) at 100 microg/kg iv. This dose is equivalent to that used in previous studies and would yield an initial plasma concentration of 0.7-1.0 microg/ml. Ventilation-perfusion inequality and pulmonary diffusion limitation were assessed by the multiple inert gas elimination technique in concert with conventional measurements of arterial and mixed venous O(2) and CO(2). TSC had no effect on ventilation, cardiac output, O(2) consumption, arterial PO(2)/saturation, or pulmonary O(2) diffusing capacity. There were minor reductions in ventilation-perfusion mismatching (logarithm of the standard deviation of perfusion fell from 0.48 to 0.43, P = 0.001) and in CO(2) output and respiratory exchange ratio (P = 0.05), which may have been due to TSC or to persisting effects of the first exercise bout. Spectrophotometry revealed that TSC disappeared from plasma with a half time of approximately 10 min. We conclude that, in this model of extensive pulmonary O(2) diffusion limitation, TSC as given has no effect on O(2) exchange or transport. Whether the original hypothesis is invalid, the dose of TSC was too low, or plasma diffusion of O(2) is not rate limiting without TSC cannot be discerned from the present study.

The organization of the gamma-glutamyl transferase genes and other low copy repeats in human chromosome 22q11.

A clone map consisting of YACs, cosmids, and fosmids has been constructed covering low copy repeat regions of human chromosome 22q11. A combination of clone restriction digest analysis, single-copy landmark content analysis, HindIII-Sau3AI fingerprinting, and sequencing of PCR products derived from clones was required to resolve the map in this region. Seven repeat-containing contigs were placed in 22q11, five containing gamma-glutamyl transferase (GGT) sequences described previously. In one case, a single interval at the resolution of the YAC map was shown to contain at least three GGT sequences after higher resolution mapping. The sequence information was used to design a rapid PCR/restriction digest technique that distinguishes the GGT loci placed in the YAC map. This approach has allowed us to resolve the previous cDNA and mapping information relating to GGT and link it to the physical map of 22q11.

Utility of leg ultrasonography in suspected symptomatic isolated calf deep venous thrombosis.

PURPOSE: To evaluate the utility of duplex ultrasonography in patients with suspected symptomatic, isolated calf deep venous thrombosis. PATIENTS AND METHODS: Thirty patients with clinically suspected isolated calf deep venous thrombosis were examined with both duplex ultrasonography and contrast venography and the results were compared. RESULTS: Venography detected 7 cases of isolated calf deep venous thrombosis, all of which were also detected by ultrasonography. Ultrasound identified an additional 3 cases of soleal vein thrombosis, but venography did not visualize these veins. Of the 20 negative ultrasound studies, 11 were technically inadequate; however, no false-negative ultrasound studies were noted. CONCLUSIONS: Compression ultrasonography may be reliable for the evaluation of patients with suspected symptomatic infrapopliteal deep venous thrombosis. Its apparent superiority to contrast venography in visualizing muscular calf veins warrants further study; however, the high rate of technical inadequacy in ultrasound studies observed here, if confirmed in larger studies, may limit the usefulness of ultrasound in this setting.

Medical waste. The growing issues of management and disposal.

When addressing the impact of medical waste management and regulatory controls on the health care industry, it is important to remember that as long as modern medicine continues to maintain and sustain its current quality of life and wellness standards, industry will continue to generate various byproducts that have adverse effects on both people and the environment. It is important, therefore, to carefully evaluate the impact of societal demands. Unless government, industry, environmental groups, and health care providers abandon their current adversarial relationships and work together to solve shared problems, there will be no improvement in the growing problem of medical waste. The long-term solutions to today's growing waste problems depend to a great extent on human factors and the willingness of industry, medical community, and governmental bodies to cooperate with each other, recognizing the cause-effect relationship of a continued demand for disposable products. There are many pieces to the waste management puzzle. Obviously, surgeons cannot perform surgery without exposure to blood, tissue or body fluids, and nurses cannot maintain asepsis without sterile products. Because the health care team cannot totally eliminate the source of medical waste, they must learn to more effectively manage and control it. Health care professionals must encourage industry and government to work together to develop standards for products and materials used as barriers and use more biodegradable materials. Health care facilities must learn to minimize the amount of medical waste designated as regulated or infectious. Segregating potentially infectious material from clean waste at the point of generation may reduce both volume and cost.