Snapshots of nascent RNA reveal cell- and stimulus-specific responses to acute kidney injury

The current strategy to detect acute injury of kidney tubular cells relies on changes in serum levels of creatinine. Yet serum creatinine (sCr) is a marker of both functional and pathological processes and does not adequately assay tubular injury. In addition, sCr may require days to reach diagnostic thresholds, yet tubular cells respond with programs of damage and repair within minutes or hours. To detect acute responses to clinically relevant stimuli, we created mice expressing Rosa26-floxed-stop uracil phosphoribosyltransferase (Uprt) and inoculated 4-thiouracil (4-TU) to tag nascent RNA at selected time points. Cre-driven 4-TU-tagged RNA was isolated from intact kidneys and demonstrated that volume depletion and ischemia induced different genetic programs in collecting ducts and intercalated cells. Even lineage-related cell types expressed different genes in response to the 2 stressors. TU tagging also demonstrated the transient nature of the responses. Because we placed Uprt in the ubiquitously active Rosa26 locus, nascent RNAs from many cell types can be tagged in vivo and their roles interrogated under various conditions. In short, 4-TU labeling identifies stimulus-specific, cell-specific, and time-dependent acute responses that are otherwise difficult to detect with other technologies and are entirely obscured when sCr is the sole metric of kidney damage.

Unique Transcriptional Programs Identify Subtypes of AKI

Two metrics, a rise in serum creatinine concentration and a decrease in urine output, are considered tantamount to the injury of the kidney tubule and the epithelial cells thereof (AKI). Yet neither criterion emphasizes the etiology or the pathogenetic heterogeneity of acute decreases in kidney excretory function. In fact, whether decreased excretory function due to contraction of the extracellular fluid volume (vAKI) or due to intrinsic kidney injury (iAKI) actually share pathogenesis and should be aggregated in the same diagnostic group remains an open question. To examine this possibility, we created mouse models of iAKI and vAKI that induced a similar increase in serum creatinine concentration. Using laser microdissection to isolate specific domains of the kidney, followed by RNA sequencing, we found that thousands of genes responded specifically to iAKI or to vAKI, but very few responded to both stimuli. In fact, the activated gene sets comprised different, functionally unrelated signal transduction pathways and were expressed in different regions of the kidney. Moreover, we identified distinctive gene expression patterns in human urine as potential biomarkers of either iAKI or vAKI, but not both. Hence, iAKI and vAKI are biologically unrelated, suggesting that molecular analysis should clarify our current definitions of acute changes in kidney excretory function.

Comparison of shear bond strength of aesthetic restorative materials

Aim:

The present study was conducted to determine and compare the shear bond strengths of Conventional glass ionomer; Resin-modified glass ionomer; Polyacid-modified composite and Composite Resin, and to assess and determine the mode of failure (adhesive, cohesive, mixed).

Materials and Methods:

Occlusal dentin of 40 extracted human teeth were randomly divided into four groups of ten teeth, each based on the restorative materials tested as follows: Group I: Conventional Glass Ionomer Cement (Control); Group II: Resin-modified Glass Ionomer Cement; Group III: Polyacid-modified Composite Resin; Group IV: Hybrid Composite Resin. The bonded materials were subjected to shear bond strength (SBS) testing in a Instron Universal Testing Machine (UTM) at a crosshead speed of 0.5 mm/min. The bond failure location was examined by the use of a stereomicroscope at 10× magnification. The mean SBS of Groups I–IV obtained was 3.81, 9.71, 11.96 and 18.16 MPa, respectively. Comparison of mean shear bond strengths of all groups was done by one way ANOVA test and comparison of means in between groups by the Student's t test.

Conclusion:

It is concluded that the compomer restorative materials show higher shear bond strength than conventional glass-ionomer and resin-modified glass-ionomer, but less than composite resin.

Chronic toxicity/carcinogenicity study of carmine of cochineal in the rat

Carmine was fed continuously to groups of 54 males and 54 females at dietary levels providing 50, 150 or 500 mg/kg body weight/day for up to 109 wk. As a control, groups of 90 males and 90 females were fed the basal diet for the same period. The rats were derived from parents fed the same dietary levels for 60 days before mating and throughout pregnancy and were thus potentially exposed in utero. There were no adverse effects upon survival, growth or intakes of food and water. No changes associated with treatment were found during the periodic measurement of haematology or renal function, or in the serum chemistry or organ weights at the end of the study. Tumour incidence was not affected, and variations in the distribution of the non-tumour pathology were not considered to be due to treatment. It was concluded that carmine administered to rats in utero and for up to 109 wk is not carcinogenic and that the no-untoward-effect level is 500 mg carmine/kg body weight/day.

Congenital cardiac defects in calves

In a 14-year study of calves with cardiac defects, 36 had 78 congenital cardiac defects: ectopia cordia cervicalis (n = 10 defects), common aortic trunk (n = 3 defects), dextraposed aorta (n = 8 defects), duplicated major trunks (n = 1 defect), hypoplastic aorta (n = 2 defects), interventricular septal defect (n = 11), interatrial septal defect (n = 2), left ventricular hypoplasia (n = 10), patent ductus arteriosus (n = 5), patent foramen ovale (n = 5), right ventricular hypoplasia (n = 10), cor triloculare biatriatum (n = 1), endocardial fibroelastosis with calcification (n = 3), and valvular hematomas (n = 7). All septal defects were high in location and ranged from 5 to 35 mm in diameter. One calf with a septal defect also had bilateral microphthalmia.

Short-term-toxicity of 4-methyl-1-phenylpentan-2-ol in rats

Groups of 15 male and 15 female rats were given diets to provide intakes of 0 (control), 10, 40 or 160 mg 4-methyl-1-phenylpentan-2-ol/kg/day for 13 wk. No effects attributable to treatment were seen in the 10-mg/kg/day dose group. At 40 mg/kg/day the only finding was a decrease in serum glucose in males. This was of questionable toxicological significance. At 160 mg/kg/day a reduction in weight gain, probably due to unpalatability, a mild proteinuria in the females, an increased relative liver weight in males, increased caecal weights, a reduction in serum glucose and a lower reticulocyte count were recorded. No changes were observed in the histopathological examination. The no-untoward-effect level established in this study was 10 mg/kg/day.

Hydatidiform moles in Holstein cattle

Two hydatidiform moles from Holstein cattle are reported. One was observed after the birth of a healthy calf and the second following abortion of a fetus with osteopetrosis.

Effects of intratesticular aflatoxin B1 on rat testes and blood estrogens

An investigation of the effects of aflatoxin B1 on rat testes and plasma estrogens is reported. A normal saline-suspended aflatoxin B1 was injected into right testes of mature Sprague-Dawley rats at doses of 0, 5, 10, 25 or 50 micrograms. Effects were evaluated by histopathological alterations of the testes and by levels of plasma estrogens estimated by a modified Dextron-Charcoal radioimmune assay. Significant gross lesions were present in testes injected with the 50 microgram dose. There was a 50% reduction in size and weight as compared to the left testis. Histological changes were dose-dependent, with minimal or no changes at 5 micrograms and maximal effects at 50 micrograms. The lesions varied from mild testicular degeneration to complete disappearance of cellular components. Interstitial cell proliferation, occasional calcification of seminiferous tubules, and absence of spermatogenesis and spermatozoa were extreme toxic effects. Estrogen concentrations in injected rats were reduced compared to those of control and normal rats. This study suggested that following intratesticular aflatoxin B1 exerts a direct toxic effect on testes with a reduction in plasma estrogen levels.

Renal oxalosis in neonatal calves

Kidney tissures were collected from 142 calves during a study of pre- and perinatal mortality. Fifty-six calves had oxalate crystals in their renal tissue. Thirty-four of the 56 had either single or multiple congenital defects, mostly of the skeleton. Twenty-two of the 56 died of causes other than congenital defects. The renal oxalosis was more pronounced in those calves affected with congenital anomalies.

Influence of dietary protein on the effect of coumaphos and triflupromazine interaction in sheep

Coumaphos (8 or 15 mg/kg of body weight), triflupromazine HCl (1.1 mg/kg of body weight), or isotonic saline solution were given to 8 groups of sheep (5 per group) fed a low-or normal-dietary protein ration. One set of clinical signs, mortality rate, mean survival time, necropsy lesions, and plasma and erythrocyte cholinesterase (ChE) activity were monitored for each group. Observations suggested potentiation effect between the administered compounds. Inhibition of ChE activity was enhanced in groups given both drugs. Feeding of low-dietary protein ration adversely affected the development of clinical signs, mortality rate, mean survival time, and ChE activity. Recovery of ChE activity of triflupromazine HCl-treated animals was faster than in their respective controls, and sheep fed normal-dietary protein ration had faster ChE recovery than those fed the low-dietary protein ration. Inhibition of erythrocyte ChE found was a better index of organophosphorus toxicosis than that of plasma ChE.