Cellular transplantation of nephrons

Cellular transplantation of nephrons. Embryonic renal cellular primordia transplanted into animal hosts undergo nephrogenesis in situ, become vascularized by blood vessels of host origin, exhibit excretory function, and support life in otherwise anephric hosts. Renal primordia can be transplanted across isogeneic, allogeneic, and both concordant (rat to mouse) and highly disparate (pig to rodent) xenogeneic barriers. Here I review studies exploring the therapeutic potential for renal organogenesis posttransplantation of cellular kidney primordia.     

Renal organogenesis from transplanted metanephric primordia

One novel solution to the shortage of human organs available for transplantation envisions growing new organs in situ via xenotransplantation of developing primordia from animal embryos. It has been shown that renal primordia (metanephroi) transplanted into animal hosts undergo organogenesis in situ, become vascularized by blood vessels of host origin, and exhibit excretory function. Metanephroi can be stored for up to 3 d in vitro before transplantation with no impairment in growth or function post-implantation. Metanephroi can be transplanted across both concordant (rat to mouse) and highly disparate (pig to rodent) xenogeneic barriers. This is a review of studies exploring the therapeutic potential for renal organogenesis posttransplantation of kidney primordia.     

Regional block and DVT prophylaxis

The last few years have seen increasing concerns among anaesthetistsabout the risks of pharmacological prophylaxis for thromboembolicdisease. Increased bleeding during or after surgery is one concern,but of greater significance is the possibility of an increasedpredisposition to haematoma formation when regional block isused. Most of the recent consideration of this problem has beenin relation to vertebral canal haematoma formation after centralnerve block. Some thought must be given also to the possibilityof haematoma formation after peripheral techniques when thetarget nerve is deeply placed so that pressure cannot be usedto control bleeding after needle insertion. However, this reviewwill be focused on vertebral canal haematoma.     

Clindamycin treatment of invasive infections caused by community-acquired,methicillin-resistant and methicillin-susceptible Staphylococcus aureus in children

BACKGROUND: Community-acquired, methicillin-resistant Staphylococcus aureus (CA-MRSA) is an established pathogen in several areas of the United States, but experience with clindamycin for the treatment of invasive MRSA infections is limited. We compared the outcome of therapy for MRSA with that of methicillin-susceptible (MSSA) invasive infections in children treated with clindamycin, vancomycin or beta-lactam antibiotics. METHODS: The demographics, hospital course and outcome of children at Texas Children's Hospital between February and November 2000 and between August 2001 and August 2002 with invasive S. aureus infections were reviewed from medical records in this retrospective study. RESULTS: CA-MRSA and community-acquired methicillin-susceptible S. aureus (MSSA) caused invasive infections in 46 and 53 children, respectively. The median ages (range) of the children were: MRSA, 3.5 years (2 months to 18.6 years); MSSA, 4.8 years (3 months to 19.8 years). The sites of infection for MRSA vs. MSSA isolates, respectively, were: bacteremia, 3 vs. 6; osteomyelitis, 14 vs. 14; septic arthritis, 5 vs. 7; pneumonia, 11 vs. 3; lymphadenitis, 7 vs. 14; other, 5 vs. 8. Among MRSA patients 39 (20 received clindamycin only, 18 had vancomycin initially and 8 were treated with a beta-lactam initially) received clindamycin and 6 received vancomycin as primary therapy. Among MSSA patients, clindamycin, nafcillin or other beta-lactam antibiotics were used in 24, 18 and 9, respectively. The median number of febrile days was 3 (0 to 14) and 2 (0 to 6) for MRSA and MSSA patients, respectively (P = 0.07). The median number of days with positive blood cultures was 2 for the MRSA (n = 16) and 1 for the MSSA (n = 18) patients (P = 0.04). CONCLUSION: Clindamycin was effective in treating children with invasive infections caused by susceptible CA-MRSA isolates.     

Involvement of glutamate in ischemic neurodegeneration in isolated retina

Retinal ischemia, a major cause of visual loss, is believed to result from overexcitation of glutamate receptors. However, under euglycemic and normoxic conditions, exogenously applied glutamate is not neurotoxic in the retina. Under such conditions, exogenous glutamate typically causes glia swelling and requires very high concentrations to produce neurotoxicity. To determine whether ischemic conditions enhance the neurotoxicity of endogenous and exogenous glutamate, we examined the effects of simulated ischemia (deprivation of both glucose and oxygen) on retinal morphology and lactate dehydrogenase (LDH) release. In an ex vivo rat retinal preparation, glutamate was administered during simulated ischemia in the presence of riluzole, an inhibitor of glutamate release. Deprivation of both glucose and oxygen for 60 min at 30 degrees C produced severe acute neurodegeneration. This neurodegeneration, characterized by bull's eye formation in the inner nuclear layer and spongy appearance in the inner plexiform layer, was prevented by the combination of MK-801 and DNQX, antagonists of N-methyl-D-aspartate (NMDA) and non-NMDA receptors, indicating that the damage results from activation of both glutamate receptors. We also found that administration of glutamate pyruvate transaminase (alanine aminotransaminase) with pyruvate diminished the neurodegeneration during simulated ischemia. Furthermore, riluzole, an inhibitor of glutamate release, attenuated the neurodegeneration, suggesting the importance of endogenous glutamate in ischemic damage. In the presence of riluzole and simulated ischemia, exogenously applied glutamate failed to cause Müller cell swelling but was extremely neurotoxic. These results suggest that simulated ischemia enhances glutamate-mediated neurotoxicity in part by depressing glutamate uptake. When glutamate transport is impaired, sub-millimolar glutamate concentrations become profoundly neurotoxic.     

Patent ductus arteriousus in the premature neonate: current concepts in pharmacological management

In utero, the ductus arteriosus shunts deoxygenated blood away from the pulmonary artery and towards the placental circulation where foetal gas exchange occurs. As a result of an intricately intertwined network of both physiological and biochemical changes, this vessel constricts rapidly after birth. Deoxygenated blood is diverted away from the placenta and through the lungs now vital for gas exchange. Premature closure of the ductus in utero can cause pulmonary hypertension and even death. Conversely, failure to close after birth can exacerbate respiratory distress, precipitate congestive heart failure and increase the risk of subsequent intestinal ischaemia leading to necrotising enterocolitis, bronchopulmonary dysplasia, renal hypoperfusion and/or cerebral ischaemia. In this review we summarise current knowledge of the delicately orchestrated control of the ductus arteriosus, focusing on the role of cyclo-oxygenase isoforms on prostaglandin production, on the interaction between prostaglandins and oxygen, and on the effects of these on ductal patency. We also seek to describe some of the standard and nonstandard therapeutic approaches available to the clinician when natural closure fails, reviewing alternative protocols for indomethacin administration and comparing indomethacin treatment with newer approaches such as ibuprofen. In summary, we will follow the course of this unique blood vessel as it is transformed over several hours from an organ absolutely vital to survival into programmed obsolescence.     

Prevalence of risk factors for cardiovascular disease in Canadians 55 to 74 years of age: results from the Canadian Heart Health Surveys, 1986-1992

BACKGROUND: By 2016, the proportion of Canadians older than 65 years of age will increase to 16%, and there will be an increase in the absolute number of cases of cardiovascular disease in older Canadians. The Canadian Heart Health Surveys database provides information about this population upon which health policy related to cardiovascular disease can be based. This paper presents for the first time population-based data on the risk factors for cardiovascular disease in older Canadians. METHODS: Canadians from all 10 provinces participated in surveys of cardiovascular risk factors; health insurance registries were used as sampling frames. In each province, probability samples of 2200 adults 18 to 74 years old not living in institutions, on reserves or in military camps were asked to participate in interviews and to undergo testing at clinics for major risk factors for cardiovascular disease. RESULTS: A total of 2739 men (response rate 70%) and 2617 women (response rate 66%) aged 55 to 74 years participated in the survey and also provided follow-up clinical measurements at the clinic. Overall, 52% of participants were hypertensive, 26% had isolated systolic hypertension, and 30% had a total blood cholesterol level of 6.2 mmol/L or greater. Rates of current smoking were lower in women than men (17% v. 22%). Overall, 87% of men and 78% of women who were current smokers smoked at least 10 cigarettes per day. Only slightly more than half of participants exercised at least once a week for at least 15 minutes, and almost half had a body mass index of 27 or greater. In only 4% was no major risk factor for cardiovascular disease detected. INTERPRETATION: Significant numbers of older Canadians have one or more major risk factors for cardiovascular disease. Many of these risk factors are amenable to modification.     

口服Carvedilol治疗心力衰竭多中心研究(MOCHA)

标题　Ｃａｒｖｅｄｉｌｏｌ对慢性心力衰竭患者左心室功能的改善和存活的提高呈剂量相关性作者　ＢｒｉｓｔｏｗＭＲ，ＧｉｌｂｅｒｔＥＭ，ＡｂｒａｈａｍＷＴ，等　　Ｃｉｒｃｕｌａｔｉｏｎ１９９６，９４：２８０７～２８１６　　研究疾病：充血性心力衰竭。目的：对Ｃａｒｖｅｄｉｌｏｌ治疗慢性心力衰竭患者剂量－疗效特征进行评价。　　设计：随机、双盲、安慰剂对照的多中心研究，剂量效应关系研究。病人资料：共３４５名心力衰竭患者，年龄１８～８５岁，左室射血分数≤０－３５，心力衰竭症状时间≥３月，研究前所有患者必须用利…