Evaluation of Temporal Changes in Urine-based Metabolomic and Kidney Injury Markers to Detect Compound Induced Acute Kidney Tubular Toxicity in Beagle Dogs.

Urinary protein biomarkers and metabolomic markers have been leveraged to detect acute Drug Induced Kidney Injury (DIKI) in rats; however, the utility of these indicators to enable early detection of DIKI in canine models has not been well documented. Therefore, we evaluated temporal changes in biomarkers and metabolites in urine from male and female beagle dogs. Gentamicin- induced kidney lesions in male dogs were characterized by moderate to severe tubular epithelial cell degeneration/necrosis, epithelial cell regeneration and dilation; and a unique urinebased metabolomic fingerprint. These metabolite changes included time and treatment-dependent increases in lactate, taurine, glucose, lactate, alanine, and citrate as well as 9 other known metabolites. As early as 3 days post dose, gentamicin induced increases in urinary albumin, clusterin, neutrophil gelatinase associated protein (NGAL) and total protein concentrations. Urinary albumin, clusterin, and NGAL showed earlier and more robust elevations than traditional kidney safety biomarkers, blood urea nitrogen and serum creatinine. Elevations in urinary kidney injury molecule 1 (KIM-1) were less reliable for detection of gentamicin nephrotoxicity in dogs based on values generated utilizing multiple first-generation, canine-specific KIM-1 immunoassays. The metabolic fingerprint was further evaluated in male and female dogs that received Compound A which induced slightly reversible renal tubular alterations characterized as degeneration/necrosis and concurrent significant increases in urinary taurine amongst other markers. These data support further investigations to demonstrate the value of urinary metabolites, albumin, clusterin, NGAL and taurine as promising markers to enable early detection of DIKI in dogs.

Cisplatin nephrotoxicity in male beagle dogs: next-generation protein kidney safety biomarker tissue expression and related changes in urine.

This 10-day (D) study was conducted to evaluate changes in traditional and newer kidney safety biomarker expression levels in dogs. Animals received cisplatin (CDDP, 0.75 mg per kg per day) or 0.9% Saline (vehicle) for 5 days. Serum/urine samples were collected at various time points. Cage-side observations included emesis (D1-2/D4-D5/D7-9), absence of stool (D5-9/D11), soft stool (D4-7/D12), excessive salivation (D1/D3/D5-6), decreased food consumption (D5-8), decreased activity (D7-8) and/or dehydration (D7). Animals were necropsied when serum creatinine (sCr) levels measured at ≥1.9 mg dL-1, indicating significant loss of renal function; or at the end of the study (D11). When compared to controls, increases in BUN/sCr were detected on D3, D5 and/or D8. Increases in urinary total protein (Ur TP) were noted on D6. The moribund dog that was euthanized early on D7 showed insignificant increases in urinary osteopontin (Ur OPN), urinary neutrophil gelatinase-associated lipocalin (Ur NGAL), urinary clusterin (Ur CLU), sCr, serum cystatin C (sCYS C) and urinary cystatin C (Ur CYS C) on D5 when compared to controls. Insignificant increases in urinary albumin (Ur ALB) were observed from an animal that was euthanized on D7 and 1 : 2 surviving animals on D8 relative to baseline. From three dogs that were euthanized on D9, increases in Ur CLU, and/or sCYS C were noted on D8 relative to baseline. The two surviving dogs showed elevated Ur CLU and 1 : 2 surviving dogs showed elevated Ur CYS C. Decreased urinary kidney injury molecule 1 (Ur KIM-1) on D3/D5 was evident (versus baseline and controls). CDDP-induced cortico-medullary lesions were characterized as minimal to mild tubule degeneration/necrosis, dilatation, regeneration, cell alteration, intratubular casts, interstitial inflammation and vacuolization. Increased Ur OPN and Ur CLU correlated with enhanced OPN and CLU immunopositive staining in damaged cortical epithelium in the proximal tubules. Enhanced KIM-1 staining in damaged cortico-medullary tubular epithelium appeared in the absence of rises in Ur KIM-1. This study showed changes in kidney safety protein biomarkers associated with CDDP nephrotoxicity in dogs and possibly in humans.

Drugs and toxins-associated pulmonary arterial hypertension: lessons learned and challenges ahead.

Since the identification of the link between pulmonary arterial hypertension (PAH) and exposure to certain drugs and toxins nearly fifty years ago, the expanding landscape of available pharmaceuticals and illicit drugs is further fueling this association. While some causative agents in drugs and toxins associated PAH (D&T-APAH) have been identified, little is known about the exact biology and clinical implications of the disease. In this review, we discuss the historical evidence that links PAH with exposure to anorexinogens, cocaine, and methamphetamines and concentrate on what is known about potential pathogenesis, clinical manifestations, and current management. We conclude that future research should focus on studies looking at clinical outcome and susceptibility factors.

Insulin resistance in pulmonary arterial hypertension.

Although obesity, dyslipidemia and insulin resistance (IR) are well known risk factors for systemic cardiovascular disease, their impact on pulmonary arterial hypertension (PAH) is unknown. The present authors' previous studies indicate that IR may be a risk factor for PAH. The current study has investigated the prevalence of IR in PAH and explored its relationship with disease severity. Clinical data and fasting blood samples were evaluated in 81 nondiabetic PAH females. In total, 967 National Health and Nutrition Examination Surveys (NHANES) females served as controls. The fasting triglyceride to high-density lipoprotein cholesterol ratio was used as a surrogate of insulin sensitivity. While body mass index was similar in NHANES versus PAH females (28.6 versus 28.7 kg.m(-2)), PAH females were more likely to have IR (45.7 versus 21.5%) and less likely to be insulin sensitive (IS; 43.2 versus 57.8%). PAH females mostly (82.7%) had New York Heart Association (NYHA) class II and III symptoms. Aetiology, NYHA class, 6-min walk-distance and haemodynamics did not differ between IR and IS PAH groups. However, the presence of IR and a higher NYHA class was associated with poorer 6-months event-free survival (58 versus 79%). Insulin resistance appears to be more common in pulmonary arterial hypertension females than in the general population, and may be a novel risk factor or disease modifier that might impact on survival.

Non-syndromic progressive hearing loss DFNA38 is caused by heterozygous missense mutation in the Wolfram syndrome gene WFS1.

Dominantly inherited progressive hearing loss DFNA38 is caused by heterozygosity for a novel mutation in WFS1, the gene for recessively inherited Wolfram syndrome. Wolfram syndrome is defined by juvenile diabetes mellitus and optic atrophy and may include progressive hearing loss and other neurological symptoms. Heterozygotes for other Wolfram syndrome mutations generally have normal hearing. Dominant deafness defined by DFNA38 is more severe than deafness of Wolfram syndrome patients and lacks any syndromic features. In a six-generation kindred from Newfoundland, Canada, WFS1 Ala716Thr (2146 G-->A) was shared by all deaf members of the family and was specific to deaf individuals. The causal relationship between this missense mutation and deafness was supported by two observations based on haplotype and mutation analysis of the kindred. First, a relative homozygous for the mutation was diagnosed at age 3 years with insulin-dependent diabetes mellitus, the central feature of Wolfram syndrome. Second, two relatives with normal hearing had an identical haplotype to that defining DFNA38, with the exception of the base pair at position 2146. Other rare variants of WFS1 co-inherited with deafness in the family could be excluded as disease-causing mutations on the basis of this hearing-associated haplotype. The possibility that 'mild' mutations in WFS1 might be a cause of non-syndromic deafness in the general population should be explored.

Psychophysical study of six hand movements.

This study represents a continuation of a series of psychophysical studies on repetitive motions of the wrist and hand conducted at the Liberty Mutual Research Center for Safety and Health. The purpose of the study was to quantify maximum acceptable forces of six motions performed on separate days but within the context of the same experiment. The six motions were wrist flexion with a power grip, wrist extension with a power grip, wrist flexion with a pinch grip, wrist extension with a pinch grip, ulnar deviation with a power grip, and a handgrip task (with a power grip). A psychophysical methodology was used in which the subject adjusted the resistance on the handle and the experimenter manipulated or controlled all other variables. Thirty-one subjects performed the six tasks at repetition rates of 15, 20 and 25 motions/min. Subjects performed the tasks for 7 h per day, 5 days per week, for 4 weeks. The subjects were instructed to work as if they were on an incentive basis, getting paid for the amount of work performed. Symptoms were recorded by the subjects during the last 5 min of each hour. The results revealed that maximum acceptable torques ranged from 11 to 19% of maximum isometric torque depending on frequency and motion. Maximum acceptable torques for the tasks that could be compared with previous studies showed the same patterns of response. However, the selected forces were substantially lower using the mixed protocol. A table of maximum acceptable torques and forces is presented for application in the field.

The relation between pain intensity, disability, and the episodic nature of chronic and recurrent low back pain.

STUDY DESIGN: An observational study on the course of chronic and recurrent low back pain and its relation to disability and medication use performed on the basis of daily diary recording. OBJECTIVES: To provide a description of daily pain reporting by individuals with self-reported chronic and recurrent low back pain, to study how the intensity and episodic nature of low back pain is related to disability and medication use, and to classify subjects according to Von Korff's categories of chronic low back pain. SUMMARY OF BACKGROUND DATA: The natural history of low back pain has been described, and some classification schemes have been proposed, but little has been reported on pain characteristics and their relation to self-report of disability. METHODS: Daily self-reports of pain intensity, social and work disability, and medication use were collected from 94 participants with self-reported chronic or recurrent low back pain over a 6-month period. A metric for describing the episodic nature of chronic low back pain was developed. RESULTS: A significant effect of pain intensity on disability was found. During an episode, participants had significantly greater disability and medication use. Work-related disability and medication use was significantly greater in the latter half of an episode. CONCLUSIONS: Pain intensity can affect disability, but the episodic nature of low back pain also affects the ability to function in both work and personal life. Intermittent increases in pain can markedly alter disability. Chronic low back pain should not be treated as a static phenomenon.

Future directions of psychophysical studies.

Psychophysics is a very old branch of psychology that is concerned with the relationship between physical stimuli that occur in the "outside world", and the sensations they produce in the body's "inside world". According to modern psychophysical theory, the strength of a sensation is directly related to the intensity of its physical stimulus by means of a power function. The history and development of psychophysics is briefly reviewed, and the application of psychophysics to manual handling tasks and repetitive hand and wrist motion is described. The advantages and disadvantages of psychophysics are discussed. The following 4 directions for future research are suggested: further validation of the data, expansion into other areas of concern (eg, other body parts, jobs, and postures), broadening of the subject base by including symptomatic subjects, and greater inclusion of psychophysical measures (eg, pain, fatigue, and discomfort) in studies of musculoskeletal disorders.

The reduction of chronic nonspecific low back pain through the control of early morning lumbar flexion. A randomized controlled trial.

STUDY DESIGN: Eighteen-month, randomized controlled trial with partial crossover. OBJECTIVES: To test the hypothesis that the control of lumbar flexion in the early morning will significantly reduce chronic, nonspecific low back pain. SUMMARY OF BACKGROUND DATA: Previous studies have indicated an increased risk of low back pain with bending forward in the early morning, primarily because of increased fluid content in the intervertebral discs at that time. METHODS: After 6 months of recording baseline data, 85 subjects with persistent or recurring low back pain were randomly assigned to treatment and control groups. The treatment group received instruction in the control of early morning lumbar flexion. The control group received a sham treatment of six exercises shown to be ineffective in reducing low back pain. Six months later, the control group received the experimental treatment, Diaries were used to record daily levels of pain intensity, disability, impairment, and medication usage. RESULTS: Significant reductions in pain intensity (P < 0.01) were recorded for the treatment group, but not for the control group (point estimate, 33%; 95% confidence interval, 11-55%). After receiving the experimental treatment, the control group responded with similar reductions (P < 0.05). Significant reductions also were observed in total days in pain, disability, impairment, and medication usage. CONCLUSIONS: Controlling lumbar flexion in the early morning is a form of self-care with potential for reducing pain and costs associated with chronic, nonspecific low back pain.

Meteorological conditions and self-report of low back pain.

STUDY DESIGN: Six months of daily low back pain ratings for 94 individuals were tested for the influence of prevailing weather conditions during the spring, summer, and fall seasons. Intergroup differences were tested for study participants who reported weather sensitivity and for those who did not. OBJECTIVES: To investigate the relation between pain ratings and prevailing weather conditions in a population with chronic or recurrent low back pain. SUMMARY OF BACKGROUND DATA: Weather conditions have been reported to influence pain perception in some disease states, including low back pain. Investigations of this relation in chronic or recurrent low back pain have involved varied methodologies, and conflicting results have been reported. METHODS: The effects of eight weather variables reported to influence musculoskeletal pain were tested on daily pain ratings. A post hoc weather sensitivity questionnaire was used to disperse 73 individuals into groups based on perceived weather sensitivity, and group differences were tested. RESULTS: Significant effects on pain scores were found, most notably for temperature and vapor pressure. The magnitude of the effects were small compared with autocorrelation of an individual's own pain scores. Significant differences were found between the group of individuals who were insensitive to weather conditions and that of individuals with perceived sensitivity to cold temperatures. No significant intergroup differences were found for damp, rainy conditions or changes in barometric pressure. CONCLUSIONS: Weather conditions may influence subjective reporting of low back pain significantly. Although the effects are small in magnitude, they should be considered in clinical treatment of the patient with chronic, nonspecific low back pain. Pain scores may demonstrate greater interaction with certain weather conditions in individuals perceiving sensitivity to those conditions.

Five spontaneous deaths associated with Clostridium difficile in a colony of cotton-top tamarins (Saguinus oedipus).

Clostridium difficile toxin was detected in the feces of five cotton-top tamarins (Saguinus oedipus) that died spontaneously over a period of 10 weeks. Deaths occurred subsequent to antibiotic therapy for infectious diarrhea associated with Campylobacter spp. Relevant clinical signs of disease prior to death included weight loss, watery diarrhea, hematochezia, weakness, and sudden collapse. On histologic examination of the colon at necropsy, pseudomembranous colitis was evident in two cases, a lesion consistent with C. difficile lesions in humans. This finding prompted submission of feces for C. difficile toxin analysis from these five cases. Four of the tamarins were from a single room, and the fifth was housed nearby. The proximity of the cases raises the possibility of environmental contamination by resistant C. difficile spores or fecal spread of the organism as reported in hospitals, day-care centers, and nurseries. The relative importance of C. difficile and its potential role as an unrecognized cause of enteric disease secondary to antibiotic therapy in nonhuman primates is discussed.

Challenges in assessing risk factors in epidemiologic studies on back disorders.

In epidemiologic studies on musculoskeletal disorders, some risk factors, especially physical load, cannot be determined independently from the worker. Posture, movement and external load are the result both of physical work requirements forced on the worker and of the worker's capacity to adopt particular techniques. Risk factors are also adjusted in relation to the worker's health. This paper presents a dynamic model that links exposure to risk factors for back pain and disability. Its aim is to help identify core elements in exposure assessment strategies for epidemiologic studies on back disorders. In this dynamic model, risk factors are determined relative to health status in order to distinguish between etiological and prognostic factors. Measurement techniques for various risk factors are classified into self-reports, observations, and direct instrumentation. Features of commonly used techniques are discussed with respect to feasibility, accuracy, and precision. In addition, consideration is given to the optimum allocation of measurements taking into account the effects of random and systematic variation in exposure due to tasks, workplaces, and workers.

Maximum acceptable forces for repetitive ulnar deviation of the wrist.

The purpose of this experiment was to quantify maximum acceptable forces for ulnar deviation motions of the wrist at various repetition rates. Subjects grasped a handle with a power grip and moved it through a 1.40 rad (80 degrees) ulnar deviation wrist motion (similar to a knife cutting task). A psychophysical methodology was used in which the subject adjusted the resistance on the handle and the experiment manipulated or controlled all other variables. Two series of experiments were conducted. Thirteen subjects completed the first series, which investigated repetition rates of 15 and 20 motions per minute. Eleven subjects completed the second series, which investigated 15, 20, and 25 motions per minute. Subjects performed for 7 hours per day, 5 days per week, for 4 weeks in the first series and 5 weeks in the second series. The subjects were instructed to work as if they were on an incentive basis, getting paid for the amount of work they performed. Symptoms were recorded by the subjects during the last 5 minutes of each hour. The results are presented and compared with maximum acceptable forces for wrist flexion and extension.

Improvement of bioavailability of the HIV protease inhibitor SC-52151 in the beagle dog by coadministration of the CYP3A4 inhibitor, ketoconazole.

1. SC-52151, an HIV protease inhibitor, is mainly metabolized by CYP3A4 and is poorly bioavailable after oral administration. After i.v. administration of SC-52151 to the female beagle dog (2.5 mg/kg), SC-52151 was rapidly eliminated in plasma with an elimination half-life of about 1 h, a plasma clearance of 44 ml/min/kg and an apparent steady-state volume distribution of 2.2 litre/kg. The high value of plasma clearance of SC-52151 suggests an extensive hepatic first-pass metabolism since SC-52151 is highly protein bound and does not partition itself into red blood cells. 2. The extensive hepatic first-pass metabolism was reduced by coadministration of a CYP3A4 inhibitor, ketoconazole. 3. Dogs were dosed daily with ketoconazole at dose of 100 mg ketoconazole per dog (approximately 10 mg/kg) for 5 days prior to the initiation of coadministration of SC-52151 for 15 days. The doses used for SC-52151 was 0, 60 and 120 mg SC-52151/kg/day (divided t.i.d., 8-h dosing interval). Coadministration of ketoconazole improved the bioavailability of SC-52151 from 4.1 to 9.6% and also improved the Cmax of SC-52151 from 0.41 to 0.83 microgram/ml. 4. Although the absolute bioavailability of SC-52151 was still low (approximately 10%), the Cmax and AUC achieved in this study were satisfactory for conducting chronic toxicology studies. No toxicity associated with the coadministration of ketoconazole was evident. Results from this study suggest that coadministration of ketoconazole might be a practical approach to increase the exposure of SC-52151 in both preclinical and clinical studies.

A single metric for quantifying biomechanical stress in repetitive motions and exertions.

The relative effects of repetition, force and posture were studied in order to investigate how continuous biomechanical measurements can be combined into a single metric corresponding to subjective discomfort. A full factorial experiment was conducted involving repetitive wrist flexion from a neutral posture to a given angle against a controlled force. Seven subjects performed the task using two paces (20 and 4 motions/min), two force levels (15 and 45 N) and two angles (15 and 45 degrees) for 1 h each. Discomfort was reported on a 10 cm visual analogue scale anchored between 'no discomfort' and 'very high discomfort'. Repeated measures analysis of variance showed that all main effects were statistically significant (p < 0.05) and no significant interactions were observed. A linear regression model was fitted to the data and used for generating frequency weighted digital filters that shape continuous recordings of repetitive motions and exertions into an output proportional to relative discomfort. The resulting high-pass digital filter had a 22 dB/decade attenuation slope. A simulated industrial task used for validating the model involved repetitively transferring pegs across a horizontal bar and inserting them into holes against a controlled resistance. Angular wrist data were recorded using an electrogoniometer and filtered. Six subjects performed the task of the three conditions consisting of (1) 15 wrist flexion, 15 N resistance and 6 motions min, (2) 15 wrist flexion. 45 N resistance and 12 motions/min, and (3) 45 degrees wrist flexion, 45 N resistance and 15 motions/min. Subjective discomfort was reported after performing the task for 1 h. Pearson correlations between subjective discomfort ratings and the integrated filtered biomechanical data for individual subjects ranged from 0.90 to 1.00. The pooled correlation across subjects was 0.67. This approach may be useful for physical stress exposure assessment and for design of tasks involving repetitive motions and exertions.

Pathology of perbutylated-N-butyl-1-deoxynojiromycin (an alpha-glucosidase-1 inhibitor) in Sprague-Dawley rats.

Perbutylated-N-butyl-1-deoxynojiromycin (p-N-butyl-DNJ, SC-49483), an alpha-glucosidase-1 inhibitor, is a candidate anti-HIV agent targeted against viral glycoprotein processing in host cell endoplasmic reticulum. The potential toxicity of this compound was evaluated in Sprague-Dawley rats after 4, 13, or 26 wk of oral administration at doses ranging from 300 to 3,670 mg/kg/day. In these studies, the target organs of p-N-butyl-DNJ effects were thyroid gland, salivary gland, stomach, and pancreas. The most prominent histologic change in these organs was the presence of clear or lightly eosinophilic vacuoles in the cytoplasm of thyroid follicular cells, gastric chief cells, salivary gland acinar cells, and exocrine pancreatic acinar cells. Ultrastructurally, these vacuoles were consistent with dilated rough endoplasmic reticulum, which sometimes contained homogeneously stained, moderately electron-dense material. The vacuoles in thyroid follicular cells contained pale eosinophilic colloidlike material consistent with accumulated thyroglobulin, as shown by immunohistochemical staining methods. The biological functions of these organs were not adversely affected as evidenced by the absence of clinical signs and the results of selected hormonal analyses. The morphologic changes were completely reversed after a 4-wk recovery period. The incidence and severity of histologic changes were decreased after 13 and 26 wk of treatment compared to 4 wk of treatment, indicating an attenuation of the host response or adaptation to the prolonged p-N-butyl-DNJ administration. We believe that morphologic changes in thyroid follicular cells, salivary gland acinar cells, pancreatic acinar cells, and gastric chief cells were the result of nonspecific inhibition of host alpha-glucosidase(s) by p-N-butyl-DNJ, causing clinically silent perturbation in host cell glycoprotein processing and/or glycoprotein transport.

Recombinant human interleukin-3 induces extramedullary hematopoiesis at subcutaneous injection sites in cynomolgus monkeys.

Parenteral administration of recombinant hematopoietic growth factors has been sporadically associated with cutaneous complications, including injection site reactions in humans and nonhuman primates. In this study, subcutaneous injection sites were evaluated from 12 cynomolgus monkeys administered a recombinant human interleukin-3 (rhIL-3) at dose levels of 0, 70, or 700 micrograms/kg daily for 18 days. Monkeys administered rhIL-3 developed small (0.5-1-cm-diameter), firm nodules at the subcutaneous injection sites. Histologically, these nodules from 4 of 8 rhIL-3-treated monkeys contained trilineage extramedullary hematopoiesis (EMH) represented by precursors of myeloid, erythroid, and megakaryocytic series cells. The lineage of hematopoietic cells was confirmed by histochemical and immunohistochemical methods. Hematopoietic cells of myeloid and megakaryocytic lineages were more common than erythroid cells. Of myeloid cells, immature eosinophils were more common, which usually formed small sheets or clusters in the panniculus and deep dermis. This report describes, for the first time, the occurrence of cutaneous EMH at the injection sites of recombinant hematopoietic growth factors, which should be differentiated from inflammation. We believe the cutaneous EMH was the exaggerated pharmacologic effect of rhIL-3.

Psychophysical studies of repetitive wrist flexion and extension.

The purpose of this experiment was to investigate the feasibility of using psychophysical methods to determine maximum acceptable forces for various types and frequencies of repetitive wrist motion. Four adjustable work stations were built to simulate repetitive wrist flexion with a power grip, wrist flexion with a pinch grip, and wrist extension with a power grip. The study consisted of two separate experiments. Subjects worked for two days per week during the first experiment, and five days per week during the second experiment. Fifteen women completed the first experiment, working seven hours each day, two days per week, for 20 days. Repetition rates of 2, 5, 10, 15 and 20 motions per minute were used with each flexion and extension task. Maximum acceptable torques were determined for the various motions, grips, and repetition rates without dramatic changes in wrist strength, tactile sensitivity, or number of symptoms. Fourteen different women completed the second experiment, performing a wrist flexion motion (power grip) fifteen times per minute, seven hours per day, five days per week, for 23 days. There were no significant differences in maximum acceptable torque from day to day. However, the average maximum acceptable torque for a five days per week exposure was 36.3% lower than for the same task performed two days per week. Assuming that maximum acceptable torques decrease 36.3% for other repetition rates and motions, tables of maximum acceptable force were developed for female wrist flexion (power grip), female wrist flexion (pinch grip), and female wrist extension (power grip).