Correlation of coronary artery calcification with pre-hemodialysis bicarbonate levels in patients on hemodialysis

Coronary artery calcification (CAC) leads to a significant increase in cardiovascular morbidity and mortality in hemodialysis (HD) patients. Metabolic acidosis, which is common in HD patients, promotes bone resorption in human and animals as a result of buffer function of bone, and calcium and phosphate elute from bone into blood stream. However, the effect of acidosis on CAC in HD patients has never been precisely investigated. This is a cross-sectional observational study performed in a single center. One hundred and seven prevalent HD patients (35 women and 72 men) underwent electron-beam computed tomography (EBCT) to evaluate CAC score (CACS), and then we evaluated associated factors of CACS with clinical and laboratory parameters including pre-HD pH and bicarbonate levels. Pre-HD pH and bicarbonate levels were 7.35 ± 0.04, and 17.6 ± 1.8 mmol/L, respectively. The pre-HD pH had no significant correlation to CACS (r = -0.025, P = 0.81). CACS was significantly negatively correlated with pre-HD bicarbonate levels (r = -0.329, P = 0.0009) and serum albumin levels (r = -0.298, P = 0.0467), while it was positively correlated with age (r = 0.319, P = 0.0008) and HD duration (r = 0.385, P = 0.0004). Serum levels of calcium, phosphorus, intact parathyroid hormone, and use of phosphorus binders were not related to CACS. Multivariate analysis indicated that plasma pre-HD bicarbonate level was independently associated with CACS. The present study showed that blood levels of pre-HD bicarbonate were significantly associated with CAC in HD patients. Further studies are needed to confirm these results and to determine whether correction of metabolic acidosis prevents the development of CAC, one of the features of accelerated atherosclerosis in HD patients.

A novel mechanism in maggot debridement therapy: protease in excretion/secretion promotes hepatocyte growth factor production

Maggot debridement therapy (MDT) is effective for treating intractable wounds, but its precise molecular mechanism, including the association between MDT and growth factors, remains unknown. We administered MDT to nine patients (66.3 ± 11.8 yr, 5 male and 4 female) with intractable wounds of lower extremities because they did not respond to conventional therapies. Significant increases of hepatocyte growth factor (HGF) levels were observed in femoral vein blood during 48 h of MDT (P < 0.05), but no significant change was found for vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), transforming growth factor-β1 (TGF-β1), or tumor necrosis factor-α (TNF-α). We conducted NIH-3T3 cell stimulation assay to evaluate the relation between HGF and protease activity in excretion/secretion (ES) derived from maggots. Compared with the control group, HGF was significantly higher in the 0.05 μg/ml ES group (P < 0.01). Furthermore, protease inhibitors suppressed the increase of HGF (P < 0.05). The HGF expression was increased in proportion to the ES protein concentration of 0.025 to 0.5 μg/ml. In fact, ES showed stronger capability of promoting HGF production and less cytotoxicity than chymotrypsin or bromelain. HGF is an important factor involved in cutaneous wound healing. Therefore, these results suggest that formation of healthy granulation tissue observed during MDT results from the increased HGF. Further investigation to identify molecules enhancing HGF expression by MDT will contribute greatly to drug target discovery for intractable wound healing therapy.

Compensation for obesity-induced insulin resistance in dogs: assessment of the effects of leptin, adiponectin, and glucagon-like peptide-1 using path analysis

The hormonal mediators of obesity-induced insulin resistance and compensatory hyperinsulinemia in dogs have not been identified. Plasma samples were obtained after a 24-h fast from 104 client-owned lean, overweight, and obese dogs. Plasma glucose and insulin concentrations were used to calculate insulin sensitivity and β-cell function with the use of the homeostasis model assessment (HOMA(insulin sensitivity) and HOMA(β-cell function), respectively). Path analysis with multivariable linear regression was used to identify whether fasting plasma leptin, adiponectin, or glucagon-like peptide-1 concentrations were associated with adiposity, insulin sensitivity, and basal insulin secretion. None of the dogs were hyperglycemic. In the final path model, adiposity was positively associated with leptin (P < 0.01) and glucagon-like peptide-1 (P = 0.04) concentrations. No significant total effect of adiposity on adiponectin in dogs (P = 0.24) was observed. If there is a direct effect of leptin on adiponectin, then our results indicate that this is a positive relationship, which at least partly counters a negative direct relationship between adiposity and adiponectin. Fasting plasma leptin concentration was directly negatively associated with fasting insulin sensitivity (P = 0.01) and positively associated with β-cell function (P < 0.01), but no direct association was observed between adiponectin concentration and either insulin sensitivity or β-cell function (P = 0.42 and 0.11, respectively). We conclude that dogs compensate effectively for obesity-induced insulin resistance. Fasting plasma leptin concentrations appear to be associated with obesity-associated changes in insulin sensitivity and compensatory hyperinsulinemia in naturally occurring obese dogs. Adiponectin does not appear to be involved in the pathophysiology of obesity-associated changes in insulin sensitivity.

Adiposity and adiponectin in dogs: investigation of causes of discrepant results between two studies

Although one study showed lower adiponectin concentrations in obese dogs, other recent studies indicate that adiponectin might not be decreased in obese dogs, raising the possibility that the physiology of adiponectin is different in dogs than in humans. The aim of this study was to investigate possible causes of the discrepancy between the two largest studies to date that assessed the association between adiposity and adiponectin concentration in dogs, including the validity of the assay, laboratory error, and the effects of breed, sex, and neuter status on the relationship between adiposity and adiponectin concentrations. Adiponectin concentrations measured with a previously validated adiponectin ELISA were compared with those estimated by Western blotting analysis of reduced and denatured plasma samples. The possibility of laboratory error and the effect of EDTA anticoagulant and aprotinin were tested. Adiponectin concentration was measured by ELISA in 20 lean dogs (10 male and 10 female, 5 neutered in each sex). There was close correlation between adiponectin concentrations measured by ELISA and those estimated by Western blotting analysis (r = 0.90; P < 0.001). There was no substantial effect of EDTA, aprotinin, or laboratory error on the results. There was confounding by neuter status of the relationship between adiposity and adiponectin concentrations, but adiponectin concentrations were not significantly lower in male than in female lean dogs (females, 36 mg/L; males, 26 mg/L; P > 0.20) and were not significantly lower in intact than in neutered lean male dogs (intact, 28 mg/L; neutered, 23 mg/L; P = 0.49). We conclude that the adiponectin ELISA previously validated for use in dogs appears to be suitable for determination of canine adiponectin concentrations and that testosterone does not appear to have a strong effect on plasma adiponectin concentrations in dogs. Obesity might decrease adiponectin concentrations in intact but not in neutered dogs.

Formation Of Hydrogen Molecules In Crystalline Silicon Treated With Atomic Hydrogen

Hydrogen molecules have been formed in crystalline silicon at various temperatures by a hydrogen-atom remote treatment. The Raman spectrum of the vibrational lines of hydrogen molecules in crystalline silicon is detected for silicon samples treated at temperatures between 250 and 500° C. The maximum production is obtained at 400° C. The Raman spectrum of hydrogen molecules in silicon observed at room temperature exhibits a frequency shift of around 4158 cm−1 and a very broad half-width of approximately 34 cm−1. Isotope shift also can be observed at around 2990 cm−1 in silicon treated with deuterium atoms at 400° C. The frequency shifts of the observed lines are in close agreement with those reported for molecular hydrogen and deuterium in gas, liquid, and solid phases. We discuss a model for the hydrogen molecule configuration and rule out the possibility of high-pressure hydrogen molecular gas in microvoids in crystalline silicon. These results indicate that hydrogen molecules exist at the tetrahedral interstitial sites in crystalline silicon.

Coherent optical phonons of ZnO under near resonant photoexcitation

Ultrafast electron-phonon coupling dynamics in ZnO are investigated by degenerate pump-probe reflectivity measurements using near resonant 400 nm light. Because of the below-gap excitation, photocarriers are excited primarily from deep levels of intrinsic point defects. At least six coherent phonon modes, including two E(2) modes and their combination, longitudinal optical (LO) mode and its overtone (2LO), are observed. Unlike the previous resonant Raman studies using 325 nm light, the intensity of the polar LO phonons is only moderately enhanced by the Fröhlich interaction. The non-polar E(2) phonons decay considerably faster than under visible excitation, indicative of strong deformation potential interaction with photocarriers. The overdamped oscillation centered at around 20 THz is tentatively attributed to the upper branch of the plasmon-phonon coupled mode. The pump-polarization dependence of the phonon amplitudes is consistent with the impulsive Raman generation.

Serum biological antioxidant potential predicts the prognosis of hemodialysis patients

BACKGROUND

It is well known that oxidative stress is enhanced in patients with end-stage renal disease. However, little is known about the relationship between serum antioxidant capacity and clinical outcome in hemodialysis (HD) patients.

METHODS

We examined the relationship between serum biomarkers of oxidative stress and clinical outcomes including all-cause mortality, hospitalization rate and incidence of cardiovascular events in HD patients. As biomarkers of oxidative stress, we measured serum levels of coenzyme Q10 (CoQ10) and biological antioxidant potential (BAP).

RESULTS

108 patients were observed for 30 months as the follow-up periods. The survival group (n = 83) showed significantly higher BAP values compared with those in death groups (n = 25; p < 0.05). When serum BAP levels were divided into two groups by their median value, the group with higher BAP values had a better survival rate than that with lower BAP values on the Kaplan-Meier survival analysis (p = 0.05). Although serum levels of CoQ10 did not show any association with clinical outcomes, lower BAP was selected as an independent risk factor for all-cause mortality as well as the absence of angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers therapy by age-adjusted Cox regression analysis.

CONCLUSIONS

This study indicated that BAP could predict the prognosis of HD patients.

Clinicopathological characteristics of patients with IgG4-related tubulointerstitial nephritis

IgG4-related disease is a recently recognized multi-organ disorder characterized by high levels of serum IgG4 and dense infiltration of IgG4-positive cells into several organs. Although the pancreas was the first organ recognized to be affected by IgG4-related disorder in the syndrome of autoimmune pancreatitis, we present here clinico-pathological features of 23 patients diagnosed as having renal parenchymal lesions. These injuries were associated with a high level of serum IgG4 and abundant IgG4-positive plasma cell infiltration into the renal interstitium with fibrosis. In all patients, tubulointerstitial nephritis was the major finding. Although 14 of the 23 patients did not have any pancreatic lesions, their clinicopathological features were quite uniform and similar to those shown in autoimmune pancreatitis. These included predominance in middle-aged to elderly men, frequent association with IgG4-related conditions in other organs, high levels of serum IgG and IgG4, a high frequency of hypocomplementemia, a high serum IgE level, a patchy and diffuse lesion distribution, a swirling fibrosis in the renal pathology, and a good response to corticosteroids. Thus, we suggest that renal parenchymal lesions actually develop in association with IgG4-related disease, for which we propose the term 'IgG4-related tubulointerstitial nephritis.'

Differences in associated factors between aortic and mitral valve calcification in hemodialysis

Increased prevalence of aortic and mitral valve calcification has been reported in patients on hemodialysis, but it remains unknown whether aortic and mitral valve calcification arise from similar pathogenesis. We detected heart valve calcification using two-dimensional echocardiography, and we related valve calcification to various clinical parameters in patients treated with hemodialysis three times a week for more than 1 year. In 112 patients (77 men and 35 women, age 67+/-10 years, duration on hemodialysis 95+/-67 months), aortic and mitral valve calcification were observed in 84 (75.0%) and 58 (51.7%) patients, respectively. Aortic valve calcification was associated with increased age, higher serum calcium, lower serum albumin, lower total cholesterol and higher high-sensitivity C-reactive protein. Multivariate analysis showed that increased age and higher serum calcium were independently associated with aortic valve calcification. Conversely, mitral valve calcification was associated with increased age, higher high-sensitivity C-reactive protein and higher serum beta(2)-microglobulin, but not with higher serum calcium. In multivariate analysis, increased age and higher serum beta(2)-microglobulin were independently associated with mitral valve calcification. Serum beta(2)-microglobulin was associated with longer duration on hemodialysis, malnutrition inflammation (lower serum albumin and higher high-sensitivity C-reactive protein) and dyslipidemia. Considering the results in previous studies showing that the distribution of beta(2)-microglobulin amyloid deposition was consistent with that of tissue calcification in patients on hemodialysis, beta(2)-microglobulin may have pathogenic roles in valve calcification.

β3-Adrenoceptor agonist AJ-9677 reduces body fat in obese beagles

A selective beta3-adrenoceptor agonist, AJ-9677, was reported to ameliorate obesity and insulin resistance in KK-Ay mice. We examined the acute and chronic effects of AJ-9677 on obese dogs. Oral administration of AJ-9677 (0.01 or 0.1 mg/kg) to overnight fasted obese beagles produced a dose-dependent rise in the plasma levels of non-esterified fatty acids and insulin in 1h, followed by a gradual drop of the plasma glucose level. It produced no apparent abnormal behaviors, but easily detectable cutaneous flushing. Daily treatment of AJ-9677 at a lower dose (0.01 mg/kg) for three weeks produced no notable change in body weight, but at a higher dose (0.1 mg/kg) it reduced the body weight compared to a placebo treatment after seven weeks. Computed tomographic examinations revealed a remarkable reduction of body fat after the AJ treatment, being consistent with the histological observations that the adipose tissue of AJ-9677-treated dogs consisted of smaller and some multilocular adipocytes. The plasma levels of leptin and adiponectin were decreased and increased, respectively, after the AJ treatment, reflecting the reduction of adiposity. It was concluded that AJ-9677 is useful for the treatment of obesity in the dog.

Plasma leptin concentration in dogs: effects of body condition score, age, gender and breeds

Leptin is a cytokine produced by adipocytes, and plays a key role in the regulation of energy balance. In the present study, we measured plasma leptin concentrations of 166 normal and obese dogs visiting veterinary practices, and clarified the influence of age, gender and breed on plasma leptin levels in dogs. Leptin levels were higher in the dogs with higher body condition scores. There was no noticeable influence of age, gender and breed, but those in optimal puppies and obese Miniature Dachshund tended to be lower than those in corresponding groups. We conclude that plasma leptin is a reliable marker of adiposity in dogs regardless of age, gender and breed variations, and thereby useful as a blood biochemistry test for health examinations and treatment of obesity.

Canine adiponectin: cDNA structure, mRNA expression in adipose tissues and reduced plasma levels in obesity

Adiponectin is a protein synthesized and secreted by adipocytes. Decreased adiponectin is responsible for insulin resistance and atherosclerosis associated with human obesity. We obtained a cDNA clone corresponding to canine adiponectin, whose nucleotide and deduced amino acid sequences were highly identical to those of other species. Adiponectin mRNA was detected in adipose tissues, but not in other tissues, of dogs. When 22 adult beagles were given a high-energy diet for 14 weeks, they became obese, showing heavier body weights, higher plasma leptin concentrations, but lower plasma adiponectin concentrations. The adiponectin concentrations of plasma samples collected from 71 dogs visiting veterinary practices were negatively correlated to plasma leptin concentrations, being lower in obese than non-obese dogs. These results are compatible with those reported in other species, and suggest that adiponectin is an index of adiposity and a target molecule for studies on diseases associated with obesity in dogs.

Diurnal variations of serum leptin in dogs: effects of fasting and re-feeding

Leptin is a protein synthesized and secreted primarily by adipocytes, and plays a key role in the regulation of energy balance. We have reported that serum leptin is elevated in obese dogs. In the present study, we examined diurnal variations of serum leptin in the dog, with special references to feeding and fasting cycles. Four male beagles were accustomed to feed once a day at 10:00 h, and blood samples were taken every 3 h for 24-36 h. Serum leptin concentration showed clear diurnal variations, being lowest before food intake (2.3+/-0.5 ng/mL) at 09:00 h, and highest (10.5+/-2.4 ng/mL) at 18:00 h. Such diurnal variations disappeared when the dogs were fasted. Serum insulin also showed diurnal variation with higher levels at 12:00-15:00 h. When insulin or glucose was injected in the fasted dogs to mimic the post-prandial insulin rise, serum leptin concentration was significantly increased in 4-8 h, but in both cases to a lesser extents than those after food intake. The results indicate that serum leptin concentrations change diurnally in association with feeding-fasting cycles in the dog, partially due to changes in insulin secretion.

Observation of an amplitude collapse and revival of chirped coherent phonons in bismuth

We have studied the A(1g) coherent phonons in bismuth generated by high fluence ultrashort laser pulses. We observed that the nonlinear regime, where the phonons' oscillation parameters depend on fluence, consists of subregimes with distinct dynamics. Just after entering the nonlinear regime, the phonons become chirped. Increasing the fluence further leads to the emergence of a collapse and revival, which next turns into multiple collapses and revivals. This is explained by the dynamics of a wave packet in an anharmonic potential, where the packet periodically breaks up and reconstitutes in its original form, giving convincing evidence that the phonons are in a quantum state, with no classical analog.