Natural Clinopyroxene Reference Materials for in situ Sr Isotopic Analysis via LA-MC-ICP-MS.

Clinopyroxene is a major host mineral for lithophile elements in the mantle lithosphere, and therefore, its origin is vital for constraints on mantle evolution and melt generation. In situ Sr isotopic measurement of clinopyroxene has been available since the recent development of laser ablation multicollector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) in the 2000s. Therefore, there is an increasing demand for natural clinopyroxene reference materials for Sr isotope microanalysis. In this contribution, we present six natural clinopyroxene reference materials from South Africa (JJG1424) and China (YY09-47, YY09-04, YY09-24, YY12-01, and YY12-02) for Sr isotope microanalysis. The Sr content of these clinopyroxenes ranges from 50 to 340 µg g-1, which covers most natural clinopyroxene compositions. Homogeneity of these potential reference materials were investigated and evaluated in detail over a 2-year period using 193-nm nanosecond and 257-nm femtosecond laser systems coupled to either a Neptune or Neptune Plus MC-ICP-MS. Additionally, the major and trace element of these clinopyroxenes were examined by electron probe microanalyzer (EPMA) as well as solution and laser ICP-MS. The in situ 87Sr/86Sr values obtained for the six natural clinopyroxene reference materials agree well with data obtained using the thermal ionization mass spectrometer (TIMS) method. The Sr isotopic stability and homogeneity of these clinopyroxenes make them potential reference materials for in situ Sr microanalysis to correct instrumental fractionation or as quality control materials for analytical sessions. The new Sr isotope data provided here might be beneficial for microbeam analysis in the geochemical community.

Strontium isotope analyses of large herbivore habitat use in the Cape Fynbos region of South Africa.

The Cape Fynbos region of South Africa, a global biodiversity hotspot, hosted a diverse large mammal fauna till shortly after permanent European settlement (1652). How these animals survived in this exceptionally nutrient-poor environment is puzzling and it is generally believed that they restricted their movements to the more fertile shale areas. We tested the hypothesis that large herbivores avoid nutrient-poor limestone and sandstone fynbos shrublands in favour of shale-derived renosterveld vegetation using strontium (Sr) isotope analysis. If this technique could reconstruct the preferred feeding habitats of the contemporary fauna, it might also be useful for reconstructing the preferred feeding grounds of an extinct fauna. Using the assumption that small rodents have spatially restricted foraging activities, we determined the (87)Sr/(86)Sr isotope ratios of rodent teeth to establish the isotopic signal characteristic of the different geological substrates in the area. We then analysed (87)Sr/(86)Sr isotope ratios in the bones of a number of different large herbivores found in De Hoop Nature Reserve using laser ablation multi-collector inductively coupled plasma mass spectrometry. These values were compared to the bioavailable (rodent) values on the respective geological substrates. The technique identified differences in feeding substrate selection between different species and groups of the same species. The results also showed that shale renosterveld shrubland is not the exclusive source of nutrition for the large herbivores. Strikingly different isotope ratios among individuals in some populations pointed to significant dispersal events from distant sources. However, we were unable to pinpoint the exact feeding areas using Sr isotope analysis probably because some animals use a combination of substrates for feeding and because the geology of the study area is complex with graded isotope signals. We suggest that this technique is a valuable additional tool for exploring large mammal foraging behaviour on habitats associated with contrasting and less complex geology.

Mitral valve replacement at Tygerberg Hospital: a 5 year follow-up: mitral valve replacement

"This study provides 5-year follow-up data of isolated mitral valve replacements with mechanical prosthesis at a large South African tertiary hospital. It also assessed the significance of pre-operative parameters to predict mortality. This is a retrospective study of 187 patients that underwent isolated mitral valve replacement at Tygerberg Hospital from Jan 1998-Dec 2002. Twenty seven patient's data was incomplete and they were excluded from the study. All patients had rheumatic mitral valve disease and the valve lesions included mitral incompetence; mitral stenosis and mixed mitral valve disease. All patients had a mechanical prosthesis implanted (St Jude medical or Orbis bileaflet valves). The mean follow-up time was 5.41-years. The 30 day mortality was 5.62and the 5-year survival was 80. Pre-operative risk factors that significantly increased mortality were pulmonary hypertension and mitral stenosis. Valve-related complications were more common in this series compared to other First World populations but our results compare well with other Third World population groups. Valve thrombosis 4.32(0.8/yr); thromboembolism 8.71(1.61/yr); anticoagulant related haemorrhage 6.87(1.27/yr); prosthetic valve endocarditis 3.08(0.57/yr) and re-operation 8.12(1.5/yr). Conclusion: Mechanical valve replacement for mitral valve disease that requires valve replacement is still a good treatment option even in third world population groups. In our series; severe pulmonary hypertension; mitral stenosis and reoperation was statistically significantly more common in the ""non-survivors"" group."

Endoscopic urethroplasty with unseeded small intestinal submucosa collagen matrix grafts: a pilot study.

PURPOSE: We evaluated small intestinal submucosa (SIS) as a substitute for skin in endoscopic urethroplasty performed as treatment for inflammatory and iatrogenic strictures of the male bulbar urethra, and in the early treatment of bulbomembranous urethral injuries associated with recent pelvic fractures. Tissue integration and epithelialization of SIS in endoscopic urethroplasty were assessed, as was the long-term maintenance of urethral patency following this treatment. MATERIALS AND METHODS: Nine patients with bulbar urethral strictures defined by urethrography were enrolled in the study. Following optical urethrotomy the SIS grafts were tubularized over a purpose specific graft carrying balloon device and secured into the opened urethra as described for endoscopic urethroplasty. Patients were followed with urethroscopy and urethrography at regular intervals as per protocol or when symptoms arose. Failure was defined as the need for any further intervention. RESULTS: Two patients with short inflammatory strictures maintained urethral patency without any intervention at 1 and 2 years, respectively. Stricture recurrence developed in 6 patients within 3 months of surgery. Of these, 3 have undergone subsequent open urethroplasty, 2 are currently awaiting urethroplasty and 1 is maintaining urethral patency with regular self-dilatation. One patient was lost to followup. CONCLUSIONS: Endoscopic urethroplasty with unseeded SIS grafts was unsuccessful in this study.

Reduction of postischemic contractile dysfunction of the isolated rat heart by sevoflurane: comparison with halothane.

Our aims were to evaluate the effect of sevoflurane on postcardioplegic functional recovery of the isolated rat heart including the role of the adenosine triphosphate regulated potassium (K(ATP)) channels and to compare the cardioprotective effects of equipotent concentrations of halothane and sevoflurane. Isolated perfused rat hearts were subjected to 45 or 60 min normothermic cardioplegic arrest and 30 min reperfusion. Sevoflurane (0.9% and 1. 7%), halothane (0.4% and 0.8%), or sevoflurane (0.9%) plus glibenclamide (10 microM) (a K(ATP) channel blocker) were administered at different time intervals. Measurements of mechanical activity were made before and after arrest. Function during reperfusion after cardioplegic arrest was significantly depressed in both untreated and treated hearts. However, sevoflurane administered both before and after arrest, or before only, significantly improved functional recovery after 45 min of cardioplegia. This protective effect was abolished by simultaneous administration of glibenclamide, suggesting a role of the K(ATP) channel. Sevoflurane was as effective as halothane in improving postcardioplegic functional performance. After 45 min of arrest, hearts exposed to either anesthetic at both concentrations had a significantly higher work performance on discontinuation of their administration than untreated controls. After 60 min of arrest, neither anesthetic elicited protection.

Tramadol today.

Tramadol is a unique analgesic offering moderate, dose-related pain relief through its action at multiple sites. In contrast to pure opioid agonists, it has a low risk of respiratory depression, tolerance and dependence. Troublesome side-effects have been reported, but tramadol has been established as an adjunct to non-steroidal anti-inflammatory drugs in the treatment of moderate postoperative pain and to abolish shivering. It may have advantages in paediatric and day-case surgery and as an adjunct in local anaesthetic techniques. This review provides an evidence-based account of the role of tramadol in modern practice.

Topical vasoactive cream in the treatment of erectile failure: a prospective, randomized placebo-controlled trial.

OBJECTIVE: To repeat a previous study on the use of a topical treatment for erectile failure using a vasoactive cream. PATIENTS AND METHODS: Fourteen patients with erectile failure who had previously responded to intracorporeal injection therapy were enrolled in a randomized placebo-controlled trial. They were given two topical applications, comprising either a cream containing aminophylline, isosorbide dinitrate and co-dergocrine mesylate, or a placebo cream of similar appearance containing no pharmacologically active ingredients. Each patient received 16 applications, eight of the active cream and eight placebo. The creams were applied alternatively on successive occasions and the results recorded. RESULTS: The active cream, applied on 77 occasions, resulted in three good and 13 partial erections. The placebo cream, applied on 76 occasions, yielded four good and 13 partial erections. CONCLUSIONS: We were unable to reproduce the successful results reported by others; in the present study the active cream performed no better than placebo.

Survey of the health and nutrition status of a squatter community in Khayelitsha.

The findings of a nutrition and health survey in Site B, a squatter area in Khayelitsha close to Cape Town, are reported. Of the children under 6 years, 16.8% were found to be under weight for age, 23.5% were stunted and 2.5% wasted, indicating a serious nutritional crisis in this community. Children with a low-birth-weight had a 3 times greater risk of being under weight for age and a 2 times greater risk of being stunted than children with birth-weights greater than 2,500 g. Of the children born outside Cape Town, 21.9% were under weight for age compared with 13.5% of children born in Cape Town. Of the pre-school children, 4.2% had completed or were on antituberculosis treatment compared with 2% of the children in the age group 6-18 years and 3.2% of adults. Sixty per cent of the pre-school children with tuberculosis were under weight for age. Half the adult population was fully employed, and 22% of households had no wage earners. Assuming literacy after 4 years of schooling, 76% of the adults were literate, but only 2.5% had completed Standard 10. Women were generally better qualified than men.