Comparative histochemical observations on the contributions of the acrosomal vesicle and granule to the acrosomal cap in the spermatozoa of mammals

Summary By applying the periodic acid-Schiff technique to frozen sections of material fixed in weak Bouin's solution and extracted with hot pyridine, the contributions of the acrosomal vesicle and granule to the acrosomal cap have been observed in the maturing spermatozoa of the American opossum, guinea pig, rabbit, marmoset and chimpanzee. In the spermatids of the opossum, the acrosomal granule is not developed and the thin, homogeneous carbohydrate layer of the acrosomal cap is derived from the concentrated material of the acrosomal vacuole. In the guinea pig, both the acrosomal vesicle and granule make the greatest contributions to the carbohydrates of the acrosomal cap; these continue to maintain their identity in the head of mature sperm. In the rabbit, marmoset and chimpanzee, the carbohydrate material of acrosomal vesicle origin is less developed and constitutes a thin layer in the lateral portions of the acrosomal cap; the carbohydrate material in its anterior portions is mainly derived from the acrosomal granule which becomes flattened; there is also a slight thickening of the intermediate layer of the acrosomal cap in this region. The distinction between the carbohydrate contributions from the acrosomal vesicle and granule disappears in the fully formed acrosomal cap which shows a homogeneously PAS-positive intermediate layer. In the chimpanzee, the acrosomal vesicle makes a relatively very small contribution to the carbohydrate layer of the acrosomal cap which is mainly formed by spreading of material from the acrosomal granule.     

Evaluation of the prevalence and economic burden of adverse drug reactions presenting to the medical emergency department of a tertiary referral centre: a prospective study

Background  

Adverse drug reactions (ADRs) are now recognized as an important cause of hospital admissions, with a proportion ranging from 0.9–7.9%. They also constitute a significant economic burden. We thus aimed at determining the prevalence and the economic burden of ADRs presenting to Medical Emergency Department (ED) of a tertiary referral center in India     

Osteoarthritis and nutrition. From nutraceuticals to functional foods: a systematic review of the scientific evidence

The scientific and medical community remains skeptical regarding the efficacy of nutrition for osteoarthritis despite their broad acceptation by patients. In this context, this paper systematically reviews human clinical trials evaluating the effects of nutritional compounds on osteoarthritis. We searched the Medline, Embase, and Biosis databases from their inception to September 2005 using the terms random, double-blind method, trial, study, placebo, and osteoarthritis. We selected all peer-reviewed articles reporting the results of randomised human clinical trials (RCTs) in osteoarthritis that investigated the effects of oral interventions based on natural molecules. Studies on glucosamine and chondroitin sulfate were excluded. The quality of the RCTs was assessed with an osteoarthritic-specific standardised set of 12 criteria and a validated instrument. A best-evidence synthesis was used to categorise the scientific evidence behind each nutritional compound as good, moderate, or limited. A summary of the most relevant in vitro and animal studies is used to shed light on the potential mechanisms of action. Inclusion criteria were met by 53 RCTs out of the 2,026 identified studies. Good evidence was found for avocado soybean unsaponifiables. Moderate evidence was found for methylsulfonylmethane and SKI306X, a cocktail of plant extracts. Limited evidence was found for the Chinese plant extract Duhuo Jisheng Wan, cetyl myristoleate, lipids from green-lipped mussels, and plant extracts from Harpagophytum procumbens. Overall, scientific evidence exists for some specific nutritional interventions to provide symptom relief to osteoarthritic patients. It remains to be investigated whether nutritional compounds can have structure-modifying effects.     

Beneficial effect of fluorocarbon emulsion media on the function of neuromuscular preparations in vitro

The effects of liquid fluorocarbons as bathing media were determined by use of in vitro neuromuscular preparations. Rat hemidiaphragms were bathed in either oxygenated fluorocarbon (FC) emulsion or standard oxygenated Krebs solution. Contractile force in response to simple supramaximal nerve stimuli as well as to high frequency stimulation was greater, while twitch:tetanus ratio was smaller in FC emulsion. With such medium, post-tetanic potentiation of contraction was also more consistently observed. Indirectly stimulated diaphragms survived longer in FC emulsion. After cessation of oxygenation, oxygen tension (ρO(2)) of the medium declined more rapidly with Krebs than with FC emulsion; ρO(2) directly correlated with force of contraction. Similarly, in the chick biventer cervicis preparation, FC emulsion enhanced nerve-stimulated force of contraction; returning the preparation to standard Krebs solution reversed this phenomenon. Dose-resonse curves of muscle contraction in response to acetycholine and KCl administration were shifted upward during FC emulsion superfusion. Frequency of miniature endplate potentials was lower in FC emulsion than that observed in Krebs solution, measured from the same cell of the rat diaphragm. Resting membrane potentials were also greater in muscle cells sampled from FC emulsion-bathed preparations. These data suggest that FC emulsion is superior to standard Krebs solution as a bathing medium for in vitro neuromuscular preparations by virtue of the high solubility of oxygen in it.