A prospective, case controlled study of the natural history of diabetic retinopathy and maculopathy after uncomplicated phacoemulsification cataract surgery in patients with type 2 diabetes

AIM: To determine if uncomplicated phacoemulsification cataract surgery is associated with an accelerated rate of progression of diabetic retinopathy or maculopathy postoperatively. METHODS: A prospective trial of 50 type 2 diabetics undergoing monocular phacoemulsification cataract surgery by a single consultant surgeon. The grade of diabetic retinopathy and diabetic maculopathy in the operated and non-operated fellow eye was assessed preoperatively and for 12 months postoperatively. RESULTS: Overall, retinopathy progression was observed in 11 patients. In seven the retinopathy progressed in both eyes, in three it progressed in the operated eye alone, and in one it progressed in the fellow eye alone. Macular oedema was observed in 13 eyes postoperatively. Four had transient pseudophakic cystoid macular oedema and nine true diabetic maculopathy. Where maculopathy progressed it did so symmetrically in five patients, it progressed in the operated eye alone in four patients, and the fellow eye alone in two patients. There was no significant difference in the number of operated and fellow eyes whose retinopathy or maculopathy progressed postoperatively. In both the operated (OE) and non-operated (NoE) eyes retinopathy progression was associated with a higher mean HbA(1)C (OE p=0.003; NoE p=0.001) and insulin treatment (OE p=0.008, NoE p=0.04). CONCLUSION: Uncomplicated phacoemulsification cataract surgery does not cause acceleration of diabetic retinopathy postoperatively and any progression that is observed probably represents the natural history of the disease. Although macular oedema is common after cataract surgery it may follow a benign course and in many patients the development of clinically significant macular oedema postoperatively probably represents natural disease progression rather than being a direct effect of surgery.     

Relation between acute hypoxia and activation of coagulation in human beings

The risk of venous thrombosis may be increased during aeroplane flights, which may, partly, relate to activation of coagulation by hypoxia that is caused by the reduction of pressure in the aircraft cabin. To find out whether hypoxia activates coagulation, we exposed eight healthy human participants to 8 h of isocapnic hypoxia and 8 h of air as a control. Venous blood was sampled before and after the exposure and analysed for markers of activated coagulation. There were no significant changes. We conclude that hypoxia has no major effect on coagulation in the general population.     

Improving the quality of kidneys from non-heart-beating donors,using streptokinase: an animal model

BACKGROUND: Non-heart-beating donors (NHBD) offer a promising potential to increase the cadaveric organ donor pool, especially for kidneys. However, almost half of NHBD kidneys are discarded after viability assessment. This wastage is costly in both human and monetary terms. Intravascular thrombosis at the time of donor death is an event leading to failure in the viability assessment. We have developed an animal model to investigate the effects of the addition of streptokinase to the in situ flush medium before transplant in an attempt to redress the situation. METHODS: Two groups of eight healthy young Landrace Yorkshire white pigs were entered into the study. Both groups were subjected to approximately 70 min warm ischemia. Both groups received an intravascular flush with 4 L of Marshall's solution with heparin (1000 IU/L); one group of pigs also had streptokinase (1.5 MIU/L) added. After donor nephrectomy, all kidneys were machine perfused for 4 hr. Data on perfusion characteristics were taken and samples of kidney effluent were assayed for tissue damage biomarkers, glutathione S-transferase (GST) and alanine aminopeptidase (Ala-AP). Wedge sections of porcine kidneys were taken at the end of perfusion, for histological analysis. RESULTS: Data on machine perfusion parameters (temperature, mean pressure index, resistance) indicate better cooling, lower resistance, and lower mean pressure index in the streptokinase-treated group of pigs. GST and Ala-AP levels were increased in the nonstreptokinase group perfusates. Histopathological analysis of porcine kidneys indicated more ischemic injury and tissue damage in the nonstreptokinase group. CONCLUSION: The use of streptokinase in this porcine NHBD model conferred benefits to donor kidneys when assessed by machine perfusion. Markers of biochemical injury indicated that less renal tissue damage occurred with the incorporation of streptokinase in the in situ flush medium.     

Long-term renal function in kidneys from non-heart-beating donors: A single-center experience

BACKGROUND: Cadaveric kidneys from brain-stem-dead donors continue to be limited because the number of donors has reached a plateau. Wide recruitment of non-heart-beating donors (NHBD) could significantly increase the donor pool. NHBD renal transplants are underused because of the concern of poor quality graft function from such donors. In response to this perception, we reviewed 46 NHBD renal transplants performed in our center since 1998. METHODS: All NHBD kidneys were machine-perfused using the Newcastle continuous-hypothermic pulsatile preservation system before transplantation. A control heart-beating-donor (HBD) group was taken as the next consecutive HBD renal transplant to the NHBD transplant. The outcome and quality of function of the groups of renal transplants were analyzed for short-term and long-term performance. RESULTS: The renal transplant patients were matched for donor and recipient factors. Survival rates for allografts and patients were similar for 1 to 3 years. There was an increased incidence of delayed graft function in the NHBD renal transplants in the perioperative period. The creatinine clearance was 22.8+/-2.3 mL/minute for NHBD patients and 44.4+/-2.9 mL/minute for HBD patients at the time of discharge from hospital. This difference equalized after 3 months and the creatinine clearance for NHBD was 44.2+/-2.4 mL/minute and for HBD 49.2+/-3.4 mL/minute. CONCLUSIONS: Our results for NHBD renal transplants confirm that such grafts suffer primary warm ischemic injury, shown by the increased incidence of acute tubular necrosis and consequent delayed graft function. This produced poor renal function at the time of hospital discharge. After 3 months, the renal function of NHBD cases improved to the level seen in HBD patients.     

Five years of family health care in São José

In 1994, the Federal Government of Brazil enacted legislation to share the costs with municipalities of establishing or remodelling up to 20 000 health clinics, covering a population of 69 million people. S?o José clinic was established with family physicians in 1993 in a community of 3000 in the City of Curitiba. The clinic was functioning by 1995 when the Canadian four principles of Family Medicine were introduced to clinic staff. The impact of the clinic's work has measured improvements in perinatal mortality and child nutrition, reduced hepatitis A infection and produced dramatic improvements in delivery of preventive services. The presence of the clinic has empowered a poor community to demand improved municipal services that have helped to improve overall health. The introduction of Family Health Clinics in Brazil, and assistance provided by Canada, has achieved the objectives of the national Government in one sample site.     

Clinical and public health implications of macrolide-resistant Streptococcus pneumoniae

Macrolide resistance among Streptococcus pneumoniae is a growing global concern, although its specific impact on public health is not currently well defined. A Consensus Working Group was convened in March 2001 to address whether credible, scientific data substantiate macrolide resistance in S. pneumoniae as: (i) producing significant morbidity; (ii) creating attendant health and economic burdens; (iii) constituting a public health threat; and (iv) warranting intervention, including development of new antibiotics with efficacy against these strains. Despite the limitations of available clinical data, concern about the possibility of treatment failure with macrolides is being expressed in clinical practice and in formal treatment guidelines, threatening the important role of these agents in the treatment of respiratory tract infections. Further studies are required to monitor and control macrolide resistance and evaluate settings in which macrolide treatment failures are occurring, and new therapeutic interventions are needed.     

Herbivory,plant resistance,and climate in the tree ring record: interactions distort climatic reconstructions

To understand climate change, dendrochronologists have used tree ring analyses to reconstruct past climates, as well as ecological processes such as herbivore population dynamics. Such reconstructions, however, have been hindered by a lack of experiments that separate the influences of confounding impacts on tree rings, such as herbivores and the interactions of multiple factors. Our long-term experiments with scale insects on resistant and susceptible pines demonstrate three major points that are important to the application of this commonly used tool. (i) Herbivory reduced tree ring growth by 25-35%. (ii) The impact on ring growth distorted climate reconstruction, resulting in the overestimation of past moisture levels by more than 2-fold. Our data suggest that, if distortion because of herbivory has been a problem in previous reconstructions, estimates of the magnitude of recent climate changes are likely to be conservative. (iii) Our studies support a detectible plant resistance x herbivore x climate interaction in the tree ring record. Because resistance and susceptibility to herbivory are known to be genetically based in many systems, the potential exists to incorporate plant genetics into the field of dendrochronology, where it may be used to screen distortions from the tree ring record.     

Activation of glial cells by human coronavirus OC43 infection

Multiple sclerosis (MS) is an immune-mediated demyelinating disease that could be triggered by a viral infection. Coronaviruses induce an MS-like disease in rodents, are neuroinvasive in humans and can infect primary cultures of human astrocytes and microglia. Infection of the human astrocytic cell line U-373MG by the OC43 strain of human coronavirus caused an upregulation of IL-6, TNF-alpha, and MCP-1 mRNA expression. This virus also modulated the activity of matrix metalloproteinases-2 and -9 and augmented nitric oxide production in both U-373MG cells and the human microglial cell line CHME-5. Thus, a coronaviral infection of glial cells could lead to the production of inflammatory molecules that have been associated with central nervous system pathologies such as MS.