The effectiveness of Hibiscus sabdariffa L. (HS) in the treatment of risk factors associated with cardiovascular disease is assessed in this review by taking a comprehensive approach to interpreting the randomized clinical trial (RCT) results in the context of the available ethnomedical, phytochemical, pharmacological, and safety and toxicity information. HS decoctions and infusions of calyxes, and on occasion leaves, are used in at least 10 countries worldwide in the treatment of hypertension and hyperlipidemia with no reported adverse events or side effects. HS extracts have a low degree of toxicity with a LD50 ranging from 2,000 to over 5,000 mg/kg/day. There is no evidence of hepatic or renal toxicity as the result of HS extract consumption, except for possible adverse hepatic effects at high doses. There is evidence that HS acts as a diuretic, however in most cases the extract did not significantly influence electrolyte levels. Animal studies have consistently shown that consumption of HS extract reduces blood pressure in a dose dependent manner. In RCTs, the daily consumption of a tea or extract produced from HS calyxes significantly lowered systolic blood pressure (SBP) and diastolic blood pressure (DBP) in adults with pre to moderate essential hypertension and type 2 diabetes. In addition, HS tea was as effective at lowering blood pressure as the commonly used blood pressure medication Captropril, but less effective than Lisinopril. Total cholesterol, low-density lipoprotein cholesterol (LDL-C), and triglycerides were lowered in the majority of normolipidemic, hypolipidemic, and diabetic animal models, whereas high-density lipoprotein cholesterol (HDL-C) was generally not affected by the consumption of HS extract. Over half of the RCTs showed that daily consumption of HS tea or extracts had favorable influence on lipid profiles including reduced total cholesterol, LDL-C, triglycerides, as well as increased HDL-C. Anthocyanins found in abundance in HS calyxes are generally considered the phytochemicals responsible for the antihypertensive and hypocholesterolemic effects, however evidence has also been provided for the role of polyphenols and hibiscus acid. A number of potential mechanisms have been proposed to explain the hypotensive and anticholesterol effects, but the most common explanation is the antioxidant effects of the anthocyanins inhibition of LDL-C oxidation, which impedes atherosclerosis, an important cardiovascular risk factor. This comprehensive body of evidence suggests that extracts of HS are promising as a treatment of hypertension and hyperlipidemia, however more high quality animal and human studies informed by actual therapeutic practices are needed to provide recommendations for use that have the potential for widespread public health benefit.
In March 2000, an approximately 30-yr-old, male coastal mountain kingsnake (Lampropeltis zonata multifasciata) presented with disequilibrium and unresponsiveness to stimuli that ultimately lead to euthanasia. Histologically, there were foci of gliosis primarily within the caudal cerebrum, brainstem, and cervical spinal cord. Several glial cells and endothelial cells contained magenta, intranuclear inclusion bodies. Electron microscopy of the inclusions revealed paracrystalline arrays of 79-82 nm, viral-like particles. DNA in situ hybridization of sections of formalin-fixed brain using a mixture of two digoxigenin-end-labeled, adenovirus specific, oligonucleotide probes at low and high stringency was positive for adenovirus.
The Los Angeles Zoo has maintained and managed six different species of forest duikers since 1975. Over the years we have achieved relative success with the majority of these species. The maintenance and breeding of duikers has proved to be difficult at best. The major problems that we have experienced concern diet, stress-related medical conditions, neonatal mortality, and postanesthetic pneumonia. As concentrate selectors, duikers have a diet relatively low in fiber, a well-developed ability to forage selectively, a rumen bypass that is functionally important, a rapid passage and high fermentation rate for starch, and frequently encountered toxins. From an examination of the captive diet of duikers it is evident that the domestic fruits fed to duikers in captivity are not well suited for them. Duikers are highly susceptible to the slightest amount of stress. The group size in which duikers are managed has proved to be critical in the successful management of these species. In our earlier years of duiker management we often kept five or more animals together in a single exhibit. This would at times result in stress-related jaw abscesses. Our group size has since been reduced to no more than three animals in any one exhibit. Since 1977, the Los Angeles Zoo has had 92 duiker births. The survival rate past 6 months of age has been 61%. Of the 36 neonatal deaths, 42% were stillborn or died within a few hours of birth. Hypothermia and maternal neglect have been linked to infant mortality. Duikers are also easily prone to capture myopathy and regurgitation during anesthesia or capture, which can often lead to aspiration pneumonia. If at all possible, the capture and restraint of a duiker should be avoided. However, there are times when the capture or restraint (chemically or manually) of a duiker is required.
In March 2000, professionals from various duiker‐holding institutions conducted a workshop at the Wildlife Conservation Society’s Wildlife Survival Center (WCS/WSC) on St. Catherine’s Island entitled Husbandry, Nutrition, and Health of Captive Duikers. The product of this workshop was a suite of monographs, one of which dealt with veterinary issues and took the form of a series of veterinary guidelines. These guidelines are based on the general disease and management concerns of neonatal and adult duikers, and include: 1) preventive medicine recommendations with preshipment, quarantine, and routine physical examination protocols; 2) restraint and anesthesia recommendations; 3) a necropsy protocol; and 4) a summary of medical informational needs. The main intent of these protocols is to outline minimum standards of veterinary care and inquiry for duiker species in captivity. Eventually, this will result in the establishment of a consistent and comprehensive data base, from which future individuals will greatly benefit in the form of improved husbandry, nutrition, and medicine. Zoo Biol 21:197–207, 2002. © 2002 Wiley‐Liss, Inc.
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