Effects of calpain inhibitor I on multiple organ failure induced by zymosan in the rat

OBJECTIVE: Zymosan enhances the formation of reactive oxygen species, which contributes to the pathophysiology of multiple organ failure. We investigated the effects of calpain inhibitor I (5, 10, or 20 mg/kg) on the multiple organ failure caused by zymosan (500 mg/kg, administered intraperitoneally as a suspension in saline) in rats. SETTING: University research laboratory. SUBJECTS: Male Sprague-Dawley rats.INTERVENTIONS Multiple organ failure in rats was assessed 18 hrs after administration of zymosan and/or calpain inhibitor I and was monitored for 12 days (for loss of body weight and mortality rate). MEASUREMENT AND MAIN RESULTS: Treatment of rats with calpain inhibitor I (5, 10, or 20 mg/kg intraperitoneally, 1 and 6 hrs after zymosan) attenuated the peritoneal exudation and the migration of polymorphonuclear cells caused by zymosan in a dose-dependent fashion. Calpain inhibitor I also attenuated the lung, liver, and intestinal injury (histology) as well as the increase in myeloperoxidase activity and malondialdehyde concentrations caused by zymosan in the lung, liver, and intestine. Immunohistochemical analysis for nitrotyrosine and for poly(adenosine-disphosphate-ribose) revealed positive staining in lung, liver, and intestine from zymosan-treated rats. The degree of staining for nitrotyrosine and poly(adenosine-disphosphate-ribose) was reduced markedly in tissue sections obtained from zymosan-treated rats administered calpain inhibitor I (20 mg/kg intraperitoneally). Furthermore, treatment of rats with calpain inhibitor I significantly reduced the expression of inducible nitric oxide synthase and cyclooxygenase-2 in lung, liver, and intestine. CONCLUSION: This study provides the first evidence that calpain inhibitor I attenuates the degree of zymosan-induced multiple organ failure in the rat.     

Phenytoin, renal function and renin release

Phenytoin (DPH), a widely used anticonvulsant, has been shown to effect membrane transport in a wide variety of tissues. After injection, DPH is known to accumulate in high concentration in the kidney, however the renal effects of this drug have not been investigated. Therefore, these studies were designed to elucidate the effect of DPH on renal function and renin release. Dogs were anesthetized and had renal venous, aortic, brachial and ureteral catheters placed. During each of three successive experimental clearance periods, either saline, propylene glycol vehicle (V) or V + DPH (0.18 mg/kg/min) was infused via a 23-gauge needle in the left renal artery. In five dogs (Group I), the sequences of infusion was saline, (V) and (V). Five animals (Group II) differed only in that V was infused during all three periods. Seven animals (Group III) underwent sequential infusions of V, V + DPH, and V. Infusion of V alone resulted in a significant increase in systemic blood pressure from 120 to 135 mm Hg (P < .05). Significant increases after V infusion were found in urine volume (0.45 to 0.87 ml/min) (P < .05) and osmolar clearance (1.23 to 1.83 ml/min). Infusion of DPH produced a 22% increase in renal blood flow from 238 to 291 ml/min (P < .05) and a fall in renal vascular resistance from 0.51 to 0.41 mm Hg/ml/min (P < .05). Significant increases were also seen in urine volume from 0.87 to 1.58 ml/min (P < .05), urine sodium excretion (157 to 269 microEq/min) (P < .05) and osmolar clearance (1.54 to 2.62 ml/min) (P < .05). Renal renin secretion rate was unchanged in Group I and II animals but DPH infusion resulted in a 7-fold increase in renin secretion from 21 to 151 ng A-I/hr x min (P < .05). We conclude that intrarenal arterial infusion of DPH results in renal vasodilation, diuresis and natriuresis. Furthermore, this agent also stimulates renin release which may be the result of its effect on membrane transport.     

A-425619 [1-isoquinolin-5-yl-3-(4-trifluoromethyl-benzyl)-urea], a novel and selective transient receptor potential type V1 receptor antagonist, blocks channel activation by vanilloids, heat, and acid

The vanilloid receptor transient receptor potential type V1 (TRPV1) integrates responses to multiple stimuli, such as capsaicin, acid, heat, and endovanilloids and plays an important role in the transmission of inflammatory pain. Here, we report the identification and in vitro characterization of A-425619 [1-isoquinolin-5-yl-3-(4-trifluoromethyl-benzyl)-urea], a novel, potent, and selective TRPV1 antagonist. A-425619 was found to potently block capsaicin-evoked increases in intracellular calcium concentrations in HEK293 cells expressing recombinant human TRPV1 receptors (IC50 = 5 nM). A-425619 showed similar potency (IC50 = 3-4 nM) to block TRPV1 receptor activation by anandamide and N-arachidonoyl-dopamine. Electrophysiological experiments showed that A-425619 also potently blocked the activation of native TRPV1 channels in rat dorsal root ganglion neurons (IC50 = 9 nM). When compared with other known TRPV1 antagonists, A-425619 exhibited superior potency in blocking both naive and phorbol ester-sensitized TRPV1 receptors. Like capsazepine, A-425619 demonstrated competitive antagonism (pA2 = 2.5 nM) of capsaicin-evoked calcium flux. Moreover, A-425619 was 25- to 50-fold more potent than capsazepine in blocking TRPV1 activation. A-425619 showed no significant interaction with a wide range of receptors, enzymes, and ion channels, indicating a high degree of selectivity for TRPV1 receptors. These data show that A-425619 is a structurally novel, potent, and selective TRPV1 antagonist.     

Child abuse: approach and management

Child abuse is a common diagnosis in the United States and should be considered any time neglect or emotional, physical, or sexual abuse is a possibility. Although home visitation programs have been effective in preventing child maltreatment, much of the approach to and management of child abuse is directed by expert opinion or legal mandate. Any suspicion of abuse must be reported to Child Protective Services. A multidisciplinary approach is recommended to adequately evaluate and treat child abuse victims; however, the responsibility often lies with the family physician to recognize and treat these cases at first presentation to prevent significant morbidity and mortality.     

Age at Regular Drinking,Clinical Course,and Heritability of Alcohol Dependence in the San Francisco Family Study: A Gender Analysis

We examined gender differences in age of onset, clinical course, and heritability of alcohol dependence in 2,524 adults participating in the University of California San Francisco (UCSF) family study of alcoholism. Men were significantly more likely than women to have initiated regular drinking during adolescence. Onset of regular drinking was not found to be heritable but was found to be significantly associated with a shorter time to onset of alcohol dependence. A high degree of similarity in the sequence of alcohol‐related life events was found between men and women, however, men experienced alcohol dependence symptoms at a younger age and women had a more rapid clinical course. Women were found to have a higher heritability estimate for alcohol dependence (h²= .46) than men (h²= .32). These findings suggest that environmental factors influencing the initiation of regular drinking rather than genetic factors associated with dependence may in part underlie some of the gender differences seen in the prevalence of alcohol dependence in this population. (Am J Addict 2010;00:1–10)     

Epidemiology and outcomes of peritonitis in children on peritoneal dialysis in Australasia

Peritonitis is a common complication and major cause of morbidity in children on peritoneal dialysis. In this retrospective longitudinal study, we analysed data retrieved from the Australian and New Zealand Dialysis and Transplant Registry (ANZDATA) on 167 patients aged less than 18 years of age who were treated with peritoneal dialysis during the period from October 2003 to December 2007. During this period there were 100 episodes of peritonitis in 57 patients (0.71 episodes/patient-year), with Gram-positive organisms most commonly isolated (44%). Peritonitis occurred frequently in the first 6 months after starting dialysis, with survival analysis showing peritonitis-free survival rates of 72%, 56% and 36% at 6 months, 1 year and 2 years respectively. Age was a weak predictor of peritonitis on univariate analysis, but previous peritonitis was the only significant predictor in a multivariate Cox proportional hazards model (adjusted hazard ratio 2.02; 95% CI: 1.20 to 3.40, p = 0.008). Peritonitis episodes infrequently resulted in relapse (5%), recurrence (7%) or the need for either temporary or permanent haemodialysis (5% and 7% respectively) and there were no patient deaths directly attributable to peritonitis. Compared with single organism peritonitis, polymicrobial peritonitis was not associated with any statistically significant differences in outcome. Further prospective studies are required to determine the most appropriate prophylactic measures and antibiotic regimens for use in pediatric patients.     

Sirolimus is Associated With Impaired Hematopoiesis in Heart Transplant Patients? A Retrospective Analysis

Background

Proliferation signal inhibitors may adversely impact bone marrow function. We sought to describe the impact of sirolimus on hemoglobin and erythropoiesis in heart transplant recipients.

Methods

We have conducted a single-center, retrospective analysis of all heart transplant patients treated with sirolimus. We measured serum hemoglobin (Hb) at baseline and at 3 months to determine the prevalence of anemia and change in Hb after sirolimus initiation. We also characterized hematologic profile of patients to gain insights into the effects of sirolimus on erythropoiesis.

Results

There were 84 patients included in the study. The prevalence of anemia increased from 71% to 75% after sirolimus initiation. Anemic patients were more likely to be male (P = .026) and have worse renal function (glomerular filtration rate 49 ± 27 vs 70 ± 42 mL/min; P = .012). A ≥20 g/L drop in Hb was observed in 25% of the overall cohort. Patients investigated for anemia (n = 67) had a low Hb (111 ± 24 g/L), normal mean corpuscular volume (87 ± 47 FL), and low serum iron levels (10 ± 5 μmol/L) and transferrin saturation (0.22 ± 0.12). Serum ferritin was variable (263 ± 370 μg/L). Bone marrow evaluation in 19 patients revealed adequate marrow iron stores in all cases.

Conclusion

Anemia is prevalent in heart transplant patients treated with sirolimus and increases over time. Patients have a characteristic hematologic profile suggestive of anemia of chronic disease and functional iron deficiency.     

Non-clinical safety and pharmacokinetic evaluations of propylene glycol aerosol in Sprague-Dawley rats and Beagle dogs

Aerosolized propylene glycol (PG) was generated as log-normally distributed particulate clouds in different concentrations using a novel capillary aerosol generator (CAG) and evaluated in a battery of non-clinical studies intended to assess its potential inhalation and systemic toxicity in 2 species before ICH-compliant "first-time-in-man" studies. Exposures were nose-only in rats, and via face mask with oropharyngeal tube in dogs. The CAG-generated PG aerosol had a mass median aerodynamic diameter (MMAD) of 2.29μm, with a 1.56 geometric standard deviation (GSD) in the rat studies, and a MMAD of 1.34μm (1.45 GSD) in the dog studies, consistent with expected particle size exposures in man. International Congress on Harmonization (ICH) Guidelines were followed, which recommend preliminary non-clinical safety studies using the vehicle and device (CAG-PG) prior to the first human exposure including safety pharmacology, pharmacokinetic (PK) studies, single dose toxicity studies, and repeated dose toxicity studies in two species. In the rat, the only biologically relevant findings included clinical signs of ocular and nasal irritation indicated by minor bleeding around the eyes and nose, and minimal laryngeal squamous metaplasia. This finding is commonly observed in inhalation studies in the rat, and likely related to the unique sensitivity of the tissue, as well as the circuitous airflow pathway through the larynx which increases particle deposition. In the female Beagle dog, treatment-related decreases in hemoglobin, red blood cells and hematocrit were observed in the two highest exposure groups, equivalent to approximately 18 and 60mg/kg/day. In male dogs from the high dose group, similar small decreases, albeit, non-statistically significant decreases were observed in these hematological markers as well. PK studies in rats and dogs showed that the absorption of PG following pulmonary inhalation exposure occurs rapidly, and equilibrium between lung tissue and plasma is achieved quickly. With daily inhalations of PG aerosols, there is evidence of minor tissue accumulation of PG in each species. Inhalation exposure to CAG-generated PG aerosols achieved PG concentrations in the systemic circulation that were similar to those attained via the oral route. Systemic elimination of PG appears to be saturable, presumably via hepatic metabolism. PG elimination in the high dose groups for both species showed terminal plasma and lung concentration-time profiles suggesting a zero-order elimination process. There was no apparent tissue toxicity of the lung, liver and kidney in these studies. Under the conditions of these studies, the NOEL for the rat was determined to be 20mg/kg/day for the 28-day study. In the Beagle dog, the NOEL was approximately 6.05mg/kg/day for the 28-day study. Overall, these studies allowed us to conclude that PG aerosol generated with the capillary aerosol generator could be administered safely in man, with an adequate margin of safety needed to conduct "first-time-in-man" human exposure studies.