Epidemiology of urolithiasis with emphasis on ultrasound detection: a retrospective analysis of 5371 cases in Saudi Arabia.

This retrospective study was conducted to determine the prevalence of urinary calculi in the indigenous population of Saudi Arabia and compare it with expatriates of different nationalities working in Saudi Arabia with emphasis on the anatomic location of the calculi and the role of ultrasound in the detection and management. The study included 5371 patients (both sexes, mean age 36.6 years) examined by us from September 2004 to February 2008. The patients hailed from 30 countries, which included Bangladesh (42.3%), Pakistan (18.3%), Yemen (17.5%), India (6.5%), Sudan (3.4%), Saudi Arabia (2.8%), Egypt (2.3%) and Eritrea (1.7%). All patients were referred for abdominal/renal ultrasonography. Urinary calculi were detected in 1029 patients. The distribution of calculi was as follows: Renal 73.3%, pelviureteric junction 2.3%, proximal, middle and distal thirds of the ureter 13%, vesicouretic junction 9.8%, vesical 1.1% and urethral 0.5%. The prevalence of urinary calculi according to ethnic origin in descending order of frequency was Egyptians (29.5%), Pakistani (24.9%), Indian (23.3%),Yemeni (20.5%), Sudanese (17.6%), Bangladeshi (16.2%), Eritrean (15.4%) and Saudi Arabian (7.4%). Urinary calculi were found in 19.1% of the studied population. Approximately three-quarters of the calculi were located within the kidney. The nationalities with the highest prevalences were Egyptian, Pakistani and Indian.

Two future generations of blood substitutes based on polyhemoglobin-SOD-catalase and nanoencapsulation.

This paper discusses our research on two new generation blood substitutes. One is based on the crosslinking of hemoglobin, superoxide dismutase(SOD) and catalase (CAT) to form polyhemoglobin-SOD-CAT. This is being investigated for use in conditions with potential problems related to ischemia-reperfusion injuries as in severe hemorrhagic shock, stroke and other conditions. The second one is based on biodegradable polymeric nanocapsules containing hemoglobin and enzymes. In this form, the hemoglobin and enzymes are separated from the external environment. Furthermore, modifications of the polymeric membrane can result in increase in circulation time.

Proposed model for interaction between residents and residency training programs, and pharmaceutical industry.

Medical residents in training are as much targets of pharmaceutical-industry marketing as are physicians in practice. This interaction is often subtle and takes the form of sponsorship of meals at academic events, support for conference travel, books, and items such as pens and notepads. Most residency programs direct little time towards training in ethics and the critical analysis of pharmaceutical-industry marketing. We propose a model for the relationship between residents and residency programs, and the pharmaceutical industry that addresses the need for such interaction to be viewed in light of the patient-centered ethic of professional conduct and the ideal of unbiased medical practice. A committee of residents at different levels of training and two staff physicians received the mandate to examine this issue. The committee developed a set of guidelines and a proposed schema for the handling of funds from pharmaceutical companies (still not implemented). Each residency program would develop a common fund for money donated by pharmaceutical companies. This fund would be administered by a committee with defined priorities. The presence of residents on this committee under staff preceptorship would serve as a springboard for education on the subject. Guidelines for acknowledgement of sponsorship, solicitation of funds, gifts for care of patients, ongoing education, and the wider applicability of these proposals were also developed. Residents' interaction with the pharmaceutical industry during training could have lifelong influence on medical practice. We hope that our model will promote critical appraisal of the potential risks and benefits of this interaction.

Crosslinked hemoglobin-superoxide dismutase-catalase scavenges free radicals in a rat model of intestinal ischemia-reperfusion injury.

An in vivo rat model of isolated intestinal ischemia-perfusion was developed. This is used to compare the effects of crosslinked hemoglobin (PolyHb) versus crosslinked hemolobin-superoxide dismutase-catalase (PolyHb-SOD-CAT) on free radical generation in ischemia-reperfusion. Fasted, anesthetized male Sprague Dawley rats underwent midline laparotomy with cannulation of the abdominal aorta and inferior vena cava. Ligation was carried out at the renal pedicles bilaterally and the aorta and vena cava proximally at the diaphragm and distally above the femoral bifurcation. The system was flushed of blood with 20 ml of lactated Ringer's solution. The portal vein was then cannulated with distal clamping at the porta hepatis so that isolated intestinal perfusion could be achieved with the aorta as the inlet and the portal vein as the outlet. Following a 90 minute ischemic time, perfusates containing modified hemoglobin (5 g/dl) and 4-hydroxybenzoate (5 mM) were infused at 0.8 ml/min for 10 min. Portal vein effluent samples were collected at 2.5 minute intervals. Hydroxyl radical generation was assessed by an aromatic hydroxylation technique with 4-hydroxybenzoate (4HB). Reaction of hydroxyl radical with 4HB produces 3,4 dihydroxybenzoate (3,4 DHBA). In the PolyHb group, the levels of 3,4-DHBA increased 10.75-13.58 x-fold above pre-perfusion values compared to 2.25-3.75 x-fold in PolyHb-SOD-CAT group. This indicates that PolyHb-SOD-CAT is effective in reducing in vivo hydroxyl radical generation following reperfusion. Since free radicals may play a major role in the pathogenesis of ischemia-reperfusion injury, this suggests a role for PolyHb-SOD-CAT as a possible protective perfusate in intestinal reperfusion injury.