Cyclin-dependent kinase-5 prevents neuronal apoptosis through ERK-mediated upregulation of Bcl-2

Cyclin-dependent kinase-5 (Cdk5) is required for neuronal survival, but its targets in the apoptotic pathways remain unknown. Here, we show that Cdk5 kinase activity prevents neuronal apoptosis through the upregulation of Bcl-2. Treatment of SH-SY5Y cells with retinoid acid (RA) and brain-derived neurotrophic factor (BDNF) generates differentiated neuron-like cells. DNA damage triggers apoptosis in the undifferentiated cells through mitochondrial pathway; however, RA/BDNF treatment results in Bcl-2 upregulation and inhibition of the mitochondrial pathway in the differentiated cells. RA/BDNF treatment activates Cdk5-mediated PI3K/Akt and ERK pathways. Inhibition of Cdk5 inhibits PI3K/Akt and ERK phosphorylation and Bcl-2 expression, and thus sensitizes the differentiated cells to DNA-damage. Inhibition of ERK, but not PI3K/Akt, abrogates Cdk5-medidated Bcl-2 upregulation and the protection of the differentiated cells. This study suggests that ERK-mediated Bcl-2 upregulation contributes to BDNF-induced Cdk5-mediated neuronal survival.

The effects of dual blockade of the renin- angiotensin system on urinary protein and transforming growth factor-b excretion in 2 groups of patients with IgA and diabetic nephropathy

AIMS

The therapeutic benefits of dual blockade of the renin-angiotensin system (RAS) have been inconsistent on renal function and proteinuria. To know the contribution of the heterogeneity of study subjects to such inconsistency, we evaluated the effects of dual blockade of RAS in 2 groups of selected renal diseases, IgA and diabetic nephropathy. To avoid confounding by the blood pressure-reducing effects, angiotensin II receptor antagonists (ATRAs) were added on the patients with long-term, optimally controlled blood pressure taking ACE inhibitors. Twenty-four-hour urinary protein excretion rate and urinary TGF-beta1 level were measured as surrogate markers of renal injury.

METHODS

We conducted a prospective crossover trial with 14 IgA and 18 type-2-diabetic nephropathy patients showing moderate degree of proteinuria (> or = 1.0 g/day) and renal dysfunction (creatinine clearance 25 - 75/ml/min). Four to 8 mg once-daily dose of candesartan and placebo were alternatively added on ramipril dose of 5 - 7.5 mg/day for 16 weeks.

RESULTS

All baseline data except for the age factor were statistically the same between the 2 disease groups. Twenty-four-hour mean arterial blood pressures were 91.2 +/- 1.6 and 92.3 +/- 1.8 mmHg in IgA and diabetic nephropathy patients respectively at baseline (p = NS). Mean arterial pressure did not change by the addition of candesartan or placebo in both groups. The addition of candesartan (combination) reduced 24-hour urinary protein excretion rate in IgA nephropathy patients with a mean change of -12.3 +/- 4.5%, which is significantly greater compared to a mean change of -0.1 +/- 3.3% after the addition of placebo (placebo) (mean difference 12.4 +/- 5.0, 95% CI 1.2 - 23.5; p < 0.05). Urinary TGF-beta1 level was reduced considerably by the combination therapy, with a -28.9 +/- 6.0% decrease, which was significantly different to that by the placebo, with +4.3 +/- 12.4% (33.3 +/- 13.5, 3.2 - 63.3; p < 0.05). In diabetic nephropathy patients, the addition of candesartan did not reduce 24-hour urinary protein excretion rate. Mean changes of 24-hour urinary protein excretion rate were -0.8 +/- 4.7% by the combination therapy and +0.5 +/- 6.1% by placebo (mean difference 1.3 +/- 4.7, 95% CI -6.8 - 13.5; p < NS). The level of urinary TGF-beta1 was reduced by the combination therapy, with -14.3 +/- 9.5% decrease, but it did not reach statistical significance compared to placebo of +0.7 +/- 15.5% (15.0 +/- 13.5, -14.4 - 44.5; p < NS). The changes in 24-hour urinary protein excretion rate and urinary TGF-beta1 level were neither correlated with each other, nor with the change in mean arterial pressure. Significant changes in the renal function were not detected during the study period.

CONCLUSION

Definite beneficial effects of dual blockade of RAS on proteinuria and TGF-beta1 excretion were found in IgA nephropathy patients, which was independent of blood pressure-reducing effect. With our 16-week trial, such benefits were not observed in type 2 diabetic nephropathy. The reduction in urinary TGF-beta1 level suggests that the combination therapy may provide additional renoprotection through the antisclerosing effects. Based on our results, for a proper interpretation the therapeutic effects of the combination therapy should be evaluated separately according to the underlying renal disease.

Epidemiological typing of Streptococcus pneumoniae from various sources in India & Korea using Box A PCR fingerprinting

BACKGROUND & OBJECTIVES

Epidemiological typing of Streptococcus pneumoniae is necessary to study genetic relatedness among strains. The Box A PCR assay, a good epidemiological tool for high resolution typing of pneumococcal isolates, was used for comparison of strains of S. pneumoniae from Korea, an area of high penicillin resistance and India with low resistance to penicillin.

METHODS

The pneumococcal strains from Indian and Korean sources included in the study belonged to serotypes 19F, 23F, 6A & 6B. The penicillin susceptibility of the strains was confirmed by determination of minimum inhibitory concentration values. The strains were then fingerprinted using the Box A PCR protocol and the results were further analysed by Molecular Analyst Software.

RESULTS

The Box fingerprinting technique produced sharp, clear and reproducible banding patterns for strains of S. pneumoniae included in the study. There was no similarity between Indian and Korean strains at the genetic level. Among the Korean strains with similar serotypes, the level of similarity varied. Except for one pair (serotype 23F), that showed a level of homology of about 90 per cent, almost all the others showed less than 80 per cent homology. It was also seen that there was a high percentage of homology (> 90% in nasopharyngeal isolates from India belonging to serotype 19F) between isolates from similar source. Comparison of the Indian and Korean isolates of similar serotype showed low homology, except for one cluster of two strains with serotype 6B which showed 84 per cent homology (blood isolates from India and Korea).

INTERPRETATION & CONCLUSION

Box A PCR is a highly discriminatory and useful method for typing S. pneumoniae. The results of the study have shown low levels of homology between strains from within India and also between two geographically distinct areas.

Incisional hernia after corrective omentectomy for peritoneal dialysis catheter malposition

Laparotomic correction with or without omentectomy is occasionally required for malposition of a peritoneal dialysis (PD) catheter. We reviewed the incidence of incisional hernia following laparotomic PD catheter correction with or with omentectomy. From January 1996 to December 1998, PD catheters were implanted by non open-dissection technique using a trocar in 148 patients. Laparotomy for PD catheter malposition was required in 20 of the 148 patients. Omentectomy was performed simultaneously in 11 patients. After laparotomy, the wound was closed with interrupted or continuous layered polyglycolidelactide polymer sutures. Dialysis was resumed after the third or fourth day. Incisional hernia developed in 30% (6/20) of all patients undergoing laparotomy, but in none of the patients not undergoing laparotomy. The incidence increased when omentectomy was performed [5/11 (45.5%) vs 1/9 (11.1%)]. Multiparity, female sex, and laparotomy at a later time also predisposed to development of incisional hernia. Among the patients with incisional hernia, 2 patients showed multiple recurrences and 1 patient showed later leakage; PD catheters were lost in these patients. Another 3 patients continued continuous ambulatory peritoneal dialysis (CAPD) without a recurrence. The results suggest that incisional hernia is prevalent following laparotomic PD catheter correction, especially when omentectomy is performed simultaneously. Situations that seem to increase the risk of incisional hernia--inevitably encountered during corrective laparotomic omentectomy--are discussed. An evaluation is necessary concerning whether omentectomy acts as an independent risk factor for incisional hernia, and whether incisional hernia occurs more frequently when omentectomy is performed after a period on CAPD as compared with when it is performed at the time of PD catheter implantation. Laparotomic omentectomy should be performed as a last resort for the correction of PD catheter malposition.

Effects of ATP on TTX-sensitive and TTX-resistant sodium currents in rat sensory neurons

Differential effects of ATP on tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant (TTX-R) sodium currents in rat dorsal root ganglion neurons were studied using the whole-cell variation of path-clamp technique. Currents were evoked by step depolarizations to 0 mV from a holding potential of -80 mV. ATP suppressed TTX-S sodium currents while it increased TTX-R sodium currents. The effects were concentration-dependent and were reversible upon washout with ATP-free external solution. ATP-gamma-S, a hydrolysis-resistant ATP analog, also affected two types of sodium currents similarly to ATP, excluding the possibility that the effects were caused by the products of ATP hydrolysis, namely adenosine. ATP by modulating sodium currents may exert profound effects on the transmission of sensory information such as nociception.

Pseudomonas aeruginosa as a potential cause of antibiotic-associated diarrhea

Although Pseudomonas aeruginosa is not generally considered as a cause of antibiotic-associated diarrhea, several cases of diarrhea caused by P. aeruginosa have been reported. We experienced seven cases of nosocomial diarrhea presumably caused by P. aeruginosa, which was the predominant organism isolated from stool cultures. Clostridium difficile toxin was also positive in one patient. No other potential or recognized enteropathogens were identified from stools. All patients had underlying diseases and had been receiving antibiotics before the diarrheal onset. All of the seven P. aeruginosa isolates were resistant to previously given antibiotics. Diarrhea stopped three days after withdrawal of probable offending antibiotics without specific treatment in two patients. The other five patients having continuous diarrhea despite withdrawal of probable offending antibiotics, were successfully treated with antipseudomonal agents. The median duration of diarrhea after the initiation of treatment was 6.3 days. These data suggest that P. aeruginosa can be a potential cause of antibiotic-associated diarrhea. Further investigations are warranted to evaluate the possible etiologic role of P. aeruginosa in antibiotic-associated diarrhea.

Fatal pulmonary-renal syndrome manifested with immune complex crescentic glomerulonephritis in a patient with MPO-ANCA seropositivity

Recent reports have indicated that a significant number of immune complex glomerulonephritis (GN) cases are associated with antineutrophilic cytoplasmic antibody (ANCA). However, most of the reported cases were associated with underlying primary glomerular diseases. When primary glomerular diseases were not found, immune deposits tended to be non-specific and the level of ANCA is usually borderline. We report here upon a case of life-threatening pulmonary-renal syndrome manifested simultaneously with immune complex GN and myeloperoxidase (MPO)-ANCA seropositivity. A 29- year-old man was admitted with pulmonary hemorrhage and rapidly progressing renal dysfunction. On admission, ANCA revealed perinuclear staining with a titer of 1:160. The MPO-ANCA level was 59 IU by ELISA. Other serologic markers including ANA, anti-DS-DNA and anti-GBM Ab were negative. Renal biopsy showed cellular crescents in eight of 18 glomeruli. Immunofluorescence staining showed strong granular deposits of C3, C1q, IgG and IgM in the capillary loop and the mesangium. Electron microscopy showed multifocal electron dense deposits scattered in the mesangium, paramesangium, and the subendothelial and subepithelial areas. The patient initially responded to steroid and cyclophosphamide. MPO-ANCA decreased to less than 10 IU. Twenty three days after hospital discharge, the patient was re-admitted urgently with fever, generalized papulonodular skin lesions, and a recurrence of massive pulmonary hemorrhage and renal dysfunction. He died from uncontrolled pulmonary hemorrhage and respiratory insufficiency. P-ANCA titer and MPO-ANCA level at the second admission were 1:320 and 82 U/ml respectively. Interestingly, relapse was shown to be triggered by varicella zoster infection.

Involvement of oxidative stress in ascorbate-induced proapoptotic death of PC12 cells

Ascorbate is a reducing agent, but it is also known to oxidize cellular components under specific conditions. The mechanism of this oxidative action, however, is not well established. Ascorbate treatment increased lipid peroxide content in PC12 cells, but did not increase quantities of lipid peroxide when homogenates of PC12 cells were treated with ascorbate, suggesting that cellular integrity is required for ascorbate to generate lipid peroxidation. However, dehydroascorbate increased lipid peroxide production in both intact PC12 cells and the cell homogenates. These differential effects of ascorbate and dehydroascorbate on intact cells versus homogenates suggest that the dehydroascorbate in cytosol induces an oxidative stress. Ascorbate in culture medium is rapidly oxidized to dehydroascorbate, which is transported into cells by a glucose transporter (GLUT). The GLUT antagonists wortmannin and cytochalasin B, or a high concentration of glucose, blocked (14)C uptake (from ascorbate) in a time-dependent manner and suppressed lipid peroxide production in PC12 cells. These observations support the concept that ascorbate is oxidized to dehydroascorbate, which is transported into cells via GLUT. The dehydroascorbate induces oxidative stress. The oxidative stress triggered apoptosis according to ceramide production, caspase-3 activation, and TUNEL. We have concluded that ascorbate is taken up after oxidation to dehydroascorbate via a "dehydroascorbate transporter" (GLUT), and the dehydroascorbate generates an oxidative stress which triggers apoptosis. These studies have significant implications for conditions under which a high concentration of ascorbate in a tissue is released during a period of hypoxia (e.g., stroke) and taken up during a reperfusion period as dehydroascorbate. Inhibiting uptake of dehydroascorbate may offer novel therapeutic strategies to alleviate brain damage during a reperfusion period.

Carriage of antibiotic-resistant pneumococci among Asian children: a multinational surveillance by the Asian Network for Surveillance of Resistant Pathogens (ANSORP)

To investigate the nasal carriage of antibiotic-resistant pneumococci by children, anterior nasal swabs were done for 4963 children <5 years old in 11 countries in Asia and the Middle East. In total, 1105 pneumococci isolates (carriage rate, 22.3%) were collected, 35.8% of which were found to be nonsusceptible to penicillin. Prevalence of penicillin nonsusceptibility was highest in Taiwan (91.3%), followed by Korea (85.8%), Sri Lanka (76.5%), and Vietnam (70.4%). Penicillin resistance was related to residence in urban areas, enrollment in day care, and a history of otitis media. The most common serogroups were 6 (21.5%), 23 (16.5%), and 19 (15.7%). The most common clone, as assessed by pulsed-field gel electrophoresis, was identical to the Spanish 23F clone and to strains of invasive isolates from adult patients. Data in this study documented the high rate of penicillin or multidrug resistance among isolates of pneumococci carried nasally in children in Asia and the Middle East and showed that this is due to the spread of a few predominant clones in the region.

Peripheral blood mitochondrial DNA content is inversely correlated with insulin secretion during hyperglycemic clamp studies in healthy young men

Abnormalities in mitochondrial DNA(mtDNA) have been implicated in the pathogenesis of diabetes mellitus. We recently reported that decreased mtDNA content precedes the development of diabetes mellitus and is associated with parameters of insulin resistance. In this study, we examined whether there is any relation between mtDNA content and insulin secretion. We compared the mtDNA content of peripheral blood leukocytes with the parameters of insulin secretion measured by hyperglycemic clamp in a group of healthy young men. There were statistically significant correlations between mtDNA content in peripheral blood and fasting plasma insulin (r=-0.43, P<0.05) and C-peptide levels (r=-0.44, P<0.05). MtDNA content also correlated negatively with acute insulin response(r=-0.48, P<0.05), late insulin response (r=-0.50, P<0.05) during hyperglycemic clamp and insulin secretion after glucagon stimulation (r=-0.60, P<0.01). mtDNA content in peripheral blood correlated negatively with homeostasis model (HOMA) insulin resistance (r=-0.45, P<0.05) although it did not correlate with the insulin insensitivity index (M/I) during hyperglycemic clamp. In summary, the mtDNA content of peripheral blood correlated negatively with indices of insulin resistance and insulin secretion in healthy young men. The compensatory response of pancreas beta cells to insulin resistance might contribute in part to increased insulin secretion in these subjects.

Molecular typing of methicillin-resistant Staphylococcus aureus by pulsed-field gel electrophoresis: comparison of results obtained in a multilaboratory effort using identical protocols and MRSA strains

Pulsed-field gel electrophoresis (PFGE) has become the gold standard of molecular methods in epidemiological investigations. In spite of its high resolving power, use of the method has been hampered by inadequate laboratory-to-laboratory reproducibility. In the project described here we have addressed this problem by organizing a multilaboratory effort in which the same bacterial strains (subtype variants of the Iberian and Brazilian methicillin-resistant Staphylococcus aureus--MRSA--clones) were analyzed by twenty investigators in thirteen different laboratories according to an indentical protocol, which is reproduced here in detail. PFGE patterns obtained were analyzed at a central laboratory in order to identify specific technical problems that produced substandard macrorestriction patterns. The results including the specific technical problems and their most likely causes are described in this communication. Also listed are seven major epidemic clones of MRSA which have been characterized by molecular fingerprinting techniques and the prototypes of which have been deposited at the American Type Culture Collection, from where they will be available for interested investigators for the purpose of typing MRSA isolates. It is hoped that this communication will contribute to the improvement of the reproducibility and technical/aesthetic quality of PFGE analysis.

A co-operative study: clinical characteristics of 334 Korean patients with moyamoya disease treated at neurosurgical institutes (1976-1994). The Korean Society for Cerebrovascular Disease

A co-operative study was conducted to determine the clinical characteristics of patients with moyamoya disease who were diagnosed and treated at neurosurgical institutes in Korea before 1995. Twenty-six hospitals contributed 505 cases and among them, the clinical characteristics of 334 patients with definite moyamoya disease were evaluated. The number of patients began to increase from the late 1980s, and after that approximately 20 patients were treated each year. There were two age peaks: from six to 15 and from 31 to 40 years of age. Haemorrhagic manifestations occurred in approximately 43% of the patients. The major clinical manifestations were haemorrhage in adults (62.4%) and ischaemia in children (61.2%). Overall 54.5% of the patients experienced decreased consciousness levels, mainly due to intracranial haemorrhage or cerebral infarction. In the patients with ischemic manifestations, the adult patients were more likely to have cerebral infarction than the pediatric patients (80% vs. 39%) and the pediatric patients were more likely to have TIA (61% vs. 25%). Thirty eight percent of the patients underwent bypass surgery and 53% of these procedures were performed bilaterally. Treatment policies, including indications for bypass surgery and commonly used drugs, were somewhat different according to the institution. Overall favorable outcome was 73%, and the most significant factor affecting poor outcome was haemorrhagic manifestation. This article describes the characteristics of 334 patients with moyamoya disease, who were diagnosed and treated at neurosurgical institutes in Korea before 1995.

Effects of fetal bovine serum on ferrous ion-induced oxidative stress in pheochromocytoma (PC12) cells

Ferrous ion (Fe2+) has been considered to be a cause of neuronal oxidative injury. Since body fluids contain protein and serum is an essential component of tissue culture medium, we have examined the role of serum protein on Fe2+-mediated oxidative stress using PC12 cells and rat cerebral cortices. Fe2+ or the combination of ascorbate and Fe2+ increased concentrations of thiobarbituric acid reactive substances (TBARS) in PC12 cells and cerebrocortical homogenates in medium (RPMI 1640), but did not increase TBARS when the medium was supplemented with 10% fetal bovine serum. Treatment with ascorbate/Fe2+ in serum-free medium reduced endogenous glutathione (GSH) concentration in PC12 cells. However, the medium supplemented with serum did not reduce GSH concentrations. PC12 cell death induced by ascorbate/Fe2+ was alleviated by increasing serum or bovine albumin concentrations in the medium. These observations indicated that oxidative injury caused by the transition metal ion could be lessened by adding fetal bovine serum to culture medium.

Oxidative stress induced by ascorbate causes neuronal damage in an in vitro system

Of particular physiological interest, ascorbate, the ionized form of ascorbic acid, possesses strong reducing properties. However, it has been shown to induce oxidative stress and lead to apoptosis under certain experimental conditions. Ascorbate in the brain is released during hypoxia, including stroke, and is subsequently oxidized in plasma. The oxidized product (dehydroascorbate) is transported into neurons via a glucose transporter (GLUT) during a reperfusion period. The dehydroascorbate taken up by cells is reduced to ascorbate by both enzymatic and non-enzymatic processes, and the ascorbate is stored in cells. This reduction process causes an oxidative stress, due to coupling of redox reactions, which can induce cellular damage and trigger apoptosis. Ascorbate treatment decreased cellular glutathione (GSH) content, and increased the rates of lipid peroxide production in rat cortical slices. Wortmannin, a specific inhibitor of phosphatidylinositol (PI)-3-kinase (a key enzyme in GLUT translocation), prevented the ascorbate induced-decrease of GSH content, and suppressed ascorbate-induced lipid peroxide production. However, wortmannin was ineffective in reducing hydrogen peroxide (H(2)O(2))-induced oxidative stress. The oxidative stress caused ceramide accumulation, which was proportionally changed with lipid peroxides when the cortical slices were treated with ascorbate. These differential effects support the hypothesis that GLUT efficiently transports the dehydroascorbate into neurons, causing oxidative stress.

Enhanced level of n-3 fatty acid in membrane phospholipids induces lipid peroxidation in rats fed dietary docosahexaenoic acid oil

The effect of dietary docosahexaenoic acid (DHA, 22:6n-3) oil with different lipid types on lipid peroxidation was studied in rats. Each group of male Sprague-Dawley rats was pair fed 15% (w/w) of either DHA-triglycerides (DHA-TG), DHA-ethyl esters (DHA-EE) or DHA-phospholipids (DHA-PL) for up to 3 weeks. The palm oil (supplemented with 20% soybean oil) diet without DHA was fed as the control. Dietary DHA oils lowered plasma triglyceride concentrations in rats fed DHA-TG (by 30%), DHA-EE (by 45%) and DHA-PL (by 27%), compared to control. The incorporation of dietary DHA into plasma and liver phospholipids was more pronounced in the DHA-TG and DHA-EE group than in the DHA-PL group. However, DHA oil intake negatively influenced lipid peroxidation in both plasma and liver. Phospholipid peroxidation in plasma and liver was significantly higher than control in rats fed DHA-TG or DHA-EE, but not DHA-PL. These results are consistent with increased thiobarbituric acid reactive substances (TBARS) and decreased alpha-tocopherol levels in plasma and liver. In addition, liver microsomes from rats of each group were exposed to a mixture of chelated iron (Fe(3+)/ADP) and NADPH to determine the rate of peroxidative damage. During NADPH-dependent peroxidation of microsomes, the accumulation of phospholipid hydroperoxides, as well as TBARS, were elevated and alpha-tocopherol levels were significantly exhausted in DHA-TG and DHA-EE groups. During microsomal lipid peroxidation, there was a greater loss of n-3 fatty acids (mainly DHA) than of n-6 fatty acids, including arachidonic acid (20:4n-6). These results indicate that polyunsaturation of n-3 fatty acids is the most important target for lipid peroxidation. This suggests that the ingestion of large amounts of DHA oil enhances lipid peroxidation in the target membranes where greater amounts of n-3 fatty acids are incorporated, thereby increasing the peroxidizability and possibly accelerating the atherosclerotic process.

The influence of seasonal factors on the incidence of peritonitis in continuous ambulatory peritoneal dialysis in the temperate zone

Many factors contribute to the development of continuous ambulatory peritoneal dialysis (CAPD) peritonitis. The role of climate in CAPD peritonitis has received relatively little attention. We retrospectively analyzed the incidence of CAPD peritonitis according to temperature and relative humidity. Data from 80 patients were examined. The monthly mean temperature and relative humidity during study period varied between -3.4 degrees C and 25.4 degrees C and between 61% and 81%, respectively. In 1123 patient-months, 53 cases of peritonitis occurred. The occurrence of peritonitis paralleled temperature and relative humidity, being the highest (0.180 episodes/patient-month) in July (mean temperature, 24.6 degrees C; relative humidity, 81%) and lowest (0.013 episodes/patient-month) in November (mean temperature, 6.6 degrees C; relative humidity, 66%). Significant correlations were seen between the monthly frequency of CAPD peritonitis and temperature (r = 0.53, p < 0.05) and relative humidity (r = 0.59, p < 0.05). The incidence was higher in the warm season (months with a mean temperature > or = 15 degrees C, that is, May-September) than in the cold season (months with a mean temperature < 15 degrees C, that is, October-April), at 0.074 episodes/patient-month versus 0.024 episodes/patient-month, p < 0.05. We also found a tendency for gram-negative peritonitis to occur uniformly throughout the year, but for gram-positive peritonitis to increase during hot and humid months, especially the rainy month of July. Gram-positive organisms caused 50% of peritonitis from March to August, but just 17.7% from September to February. Gram-negative organisms caused 7.3% and 29.4% of peritonitis during the same periods (p < 0.05). The results indicate a clear seasonal change in the rate of CAPD peritonitis and in the causative micro-organisms. The observation that CAPD peritonitis increases in the season of high temperature and high humidity suggests the influence of climate on CAPD peritonitis in the temperate zone.

Graded unilateral cervical spinal cord injury in the rat: evaluation of forelimb recovery and histological effects

The purpose of this study was to develop a model of unilateral cervical (C4-C5) spinal cord contusion injury in the rat and to characterize the functional and histological consequences following three injury levels using a new weight-drop spinal cord injury device. We evaluated forepaw/forelimb and hindlimb functions by: (1) a horizontal ladder beam measuring paw misplacements and slips; and (2) the forelimb preference test which measures the forelimb used for pushing off to rear, for support, and to land on after rearing. Rats with a mild spinal cord injury displayed primarily a forepaw deficit (forepaw misplacements) for 8 weeks after injury. Paw preference also improved after injury, but failed to reach control levels even after 12 weeks. These rats had damage primarily to the rubrospinal, spinocervicothalamic, and the uncrossed lateral corticospinal tracts in the dorsolateral funiculus a well as some loss of the lateral spinothalamic tracts in the lateral funiculus. Rats with a moderate injury had a prominent forepaw deficit still evident at 12 weeks after injury as well as a mild but not significant hindlimb deficit. Paw preference improved slightly 12 weeks. There was a larger lesion in the dorsolateral and lateral funiculi than in mildly injured rats which extended into the ventrolateral funiculi. There was a significant loss of gray matter compared to rats with a mild injury. Rats with a severe injury displayed significant forelimb and hindlimb deficits throughout the 12 week testing period compared to rats with a mild or moderate injury, and also had a more severe paw preference bias (90%). The lesion encompassed the entire dorsolateral, lateral and ventrolateral funiculi with some disruption of the ventral funiculus. There was more significant gray matter necrosis compared to rats with either a mild or moderate injury. Thus, the spinal cord injury device we used may be useful for studying graded cervical spinal cord injury in rats and potential treatments or interventions, because both the behavioral and histological effects are reproducible and consistent.

Enhanced neutrophil functions by recombinant human granulocyte colony-stimulating factor in diabetic patients with foot infections in vitro

This study was performed to evaluate the effect of granulocyte-colony stimulating factor on neutrophil functions in diabetic patients with active foot infections in vitro. Twelve diabetic patients with foot infections and 12 normal volunteers were enrolled. Neutrophils from peripheral blood were incubated with granulocyte colony-stimulating factor (G-CSF, 50 ng/mL) for 20 min. Superoxide production of neutrophils was measured by the reduction of ferricytochrome C. Neutrophil phagocytosis was assayed using Staphylococcus aureus and the weighted phagocytic index was calculated. Superoxide production of neutrophils in diabetic patients with foot infections was 7.7 (unit: nmol/2 x 10(5) cells/60 min), which was significantly lower than that in controls (12.0) (p<0.05). G-CSF increased neutrophil superoxide production to 12.1 in diabetic patients with foot infections and to 19.8 in controls (p<0.05 for each). Weighted phagocytic index in diabetic patients with foot infections was 0.77, which was not significantly different from that of the controls (0.69). Weighted phagocytic index was increased significantly by G-CSF to 0.88 in diabetic patients with foot infections and to 0.79 in controls (p<0.05 for each). In conclusion, G-CSF significantly enhanced neutrophil functions in diabetic patients with foot infections in vitro.

Effect of iron and ascorbate on cyclosporine-induced oxidative damage of kidney mitochondria and microsomes

The stimulatory effect of iron and ascorbate on the damaging action of cyclosporine in kidney mitochondria, microsomes and epithelial cells was examined. Cyclosporine induced malondialdehyde formation and hydrogen peroxide production in mitochondria and attenuated the activity of MnSOD and glutathione peroxidase. The damaging effect of cyclosporine (50 microM) plus Fe2+(20 microM) on mitochondrial and microsomal lipids and proteins as well as mitochondrial thiols was greater than the summation of the oxidizing action of cyclosporine alone and Fe2+ alone. As for tissue components, iron enhanced cyclosporine-induced viability loss in kidney epithelial cells. Fe2+, EDTA and H2O2- induced 2-alpha deoxyribose degradation was attenuated by 10 mM DMSO and 200 microM DTPA but not affected by 200 microM cyclosporine. The addition of Fe2+ caused a change in the absorbance spectrum of cyclosporine in the wavelength range 230-350 nm. The simultaneous addition of cyclosporine (50 microM) and ascorbate (100 microM) showed the enhanced peroxidative effect on mitochondrial and microsomal lipids, which was inhibited by DTPA and EDTA (1 mM). Similar to iron, ascorbate enhanced cyclosporine-induced cell viability loss. The results show that iron and ascorbate promote the damaging action of cyclosporine in kidney cortex mitochondria and microsomes and in kidney epithelial cells, which may contribute to the enhancement of cyclosporine-induced nephrotoxicity.

Assessment of total body water from anthropometry-based equations using bioelectrical impedance as reference in Korean adult control and haemodialysis subjects

BACKGROUND

Several indirect prediction equations to estimate total body water (TBW) with simple demographic and anthropometric data are commonly used by researchers and dialysis units. These equations are largely based on observations in subjects of the Western hemisphere. The purpose of this study was to investigate the possible application of anthropometry-based TBW equations to a Korean adult control population and maintenance haemodialysis (HD) patients using multifrequency bioelectrical impedance analysis (BIA) as reference.

METHODS

We performed BIA and anthropometric measurements in 67 healthy adults and 101 HD patients. Four anthropometry-based equations were used: 58% of actual body weight (TBW-58), the Watson formula (TBW-W), the Hume formula (TBW-H), and the Chertow formula (TBW-C). Multifrequency BIA was performed at fasting state in controls and after HD.

RESULTS

TBW-BIA was 34.6+/-6.9 l in control and 29.9+/-5.1 l in HD patients. TBW-58 and TBW-C gave significantly greater TBWs than TBW-BIA in both control and HD subjects. The correlation coefficients of TBW-BIA with calculated TBWs were lowest in TBW-58 (0.754 in control and 0.856 in HD subjects), and highest in TBW-C (0.944 in control and 0.916 in HD subjects). Mean prediction error was greatest in the Chertow formula for control and HD patients. Mean prediction error, limits of agreement, and root mean square error were lowest between TBW-BIA and TBW-H in control and between TBW-BIA and TBW-W in HD subjects. The correlation coefficient in the Bland-Altman plot was closer to zero and parallel with TBW-W than TBW-H in control and HD subjects.

CONCLUSION

Currently available TBW equations overestimate TBW in both Korean normal control subjects and HD patients. Among them, the Watson formula appears to be the closest to TBW and to have the least bias. Based on this analysis, it is reasonable to use the Watson formula for the calculation of TBW in Korean adult control and HD subjects until an Asian-based TBW equation is available.