Formation of lead-induced inclusion bodies in primary rat kidney epithelial cell cultures: Effect of actinomycin D and cycloheximide

Cells were isolated from adult rat kidney by mild trypsin digestion and maintained in Eagles MEM-d-valine medium for 3 days to form a monolayer primary culture of epithelial cells. When these cells in monolayer were exposed to a medium containing lead nitrate (4.5 × 10^?4m) complexed with glutamic acid (5 × 10^?4m), inclusion bodies with characteristic ultrastructure were detected morphologically in the cytoplasm within 4 hr. At 24 hr after lead exposure the inclusion bodies were localized mainly in the nucleus. Addition of actinomycin D (0.05 and 5 μg/ml) or cycloheximide (5 and 10 μg/ml) directly to cultures prior to lead exposure resulted in the absence of inclusion bodies at high concentrations and in fewer inclusions at low concentrations. These inhibitors did not affect the uptake of lead by the cell; but they markedly inhibited incorporation of [³H]leucine into cellular proteins. The initial appearance of inclusion bodies in cytoplasm after lead exposure, its subsequent relocalization in the nucleus and the effect of inhibitors in these processes were also confirmed by quantitation of inclusion bodies ultrastructurally in randomly selected cells in each experiment. These results indicate that active protein synthesis is required for the formation of lead-induced inclusion bodies.     

Renal metallothionein metabolism after a reduction of renal mass. II. Effect of zinc pretreatment on the renal toxicity and intrarenal accumulation of inorganic mercury.

In the present study we examined the effects of zinc pretreatment (to induce the renal synthesis of metallothionein) on the renal accumulation and intrarenal distribution of inorganic mercury in uninephrectomized (NPX) and sham-operated (SO) rats 24 h after the animals were given a 0.75, 1.0 or 1.5 mumol/kg intravenous (i.v.) dose of inorganic mercury. We also examined the effects of zinc pretreatment on the nephropathy induced by the three doses of inorganic mercury. Zinc was administered at a dose of 306 mumol/kg (20 mg/kg) subcutaneously (s.c.) in the form of zinc sulfate once daily for 2 consecutive days prior to the administration of inorganic mercury. Following zinc pretreatment, the renal accumulation of injected inorganic mercury increased in both NPX and SO rats treated with the three doses of inorganic mercury, but the increase was significantly greater in the NPX rats. The enhanced accumulation of mercury was associated with an altered pattern in the intrarenal distribution of mercury, particularly in the NPX rats. The increased renal accumulation of mercury in both the NPX and SO rats was due primarily to its increase in the renal cortex. We have recently found that the synthesis of metallothionein in the renal cortex increases in NPX and SO rats given zinc. Therefore, it appears that there is a relationship between the content of preinduced cellular metallothionein in the cortex and the content of mercury that accumulates in the cortex. Zinc pretreatment also prevented the nephropathy induced by the three doses of inorganic mercury from occurring in both the NPX and SO rats. We propose that some of the protection may be related to the altered intrarenal accumulation and distribution of mercury that occurs after pretreatment with zinc. Hepatic accumulation of mercury also increased in both groups of rats, but the increase again was significantly greater in the NPX rats. Our findings show clearly that a significant reduction in renal mass alters the hepatic and renal accumulation of mercury when zinc pretreatment is used to induce the renal and hepatic synthesis of metallothionein. In addition, our findings show that zinc pretreatment protects both normal and remnant kidneys in rats from the nephrotoxic effects of inorganic mercury.     

Effect of acute injections of ethanol on lipid and protein-bound sialic acid in mice of different ages

Mice of different age groups (weanling, young adult and aged) were tested for changes in brain lipid- and protein-bound sialic acid (SA) 2 h after ethanol (2 g/kg, i.p.), either as a single dose or after binge dosing of five repeated doses of ethanol spaced 2 h apart. The results clarify our earlier demonstrations that acute ethanol can reduce whole brain SA. Ethanol generally decreased SA of both gangliosidic and glycoprotein origin, with the effect varying with number of doses and mouse age. Single-dose ethanol decreased both lipid-bound and protein-bound SA in young adults and decreased lipid-bound SA in aged mice. There was no effect on lipid-bound SA in weanlings, but weanlings did have a 72% decline in protein-bound SA. Repeated injections in young adults did not cause the SA decrease seen with acute injection. In both weanling and aged mice, however, repeated injections did cause large decreases in both lipid- and protein-bound SA. Small, but statistically significant, changes also occurred in free SA. Ethanol increased free SA in singly-dosed young adults and in multiply-dosed aged adults, while causing a distinct decrease in singly-dosed weanlings.     

Exogenous metallothionein and renal toxicity of cadmium and mercury in rats.

The relative tissue distribution and toxicity of cadmium (Cd) and mercury (Hg) in the liver and kidneys of rats when the metals are administered as either inorganic salts or complexed with MT were studied. Male Sprague-Dawley rats were injected (i.v.) with Cd or Hg inorganic salt of chloride or in a complex of MT at a dose of 0.3 mg/kg body weight. The concentration of MT and metals in plasma and urine was monitored for 7 days, at the end of which the rats were killed. Injection of both HgCl2 and Hg-MT induced the synthesis of MT only in the kidney but not in the liver, whereas CdCl2 and Cd-MT injections induced MT synthesis in both liver and kidney, respectively. Plasma MT levels increased 3 days after CdCl2 but not after HgCl2 injection, suggesting that hepatic MT may be an important source of plasma MT under our experimental conditions. Renal toxicity was observed morphologically and by an increase in blood urea nitrogen, plasma creatinine, proteinuria in rats injected with Cd-MT and both forms of Hg. Urinary MT excretion was significantly elevated in Cd-MT injected rats compared with those injected with CdCl2. However, HgCl2 and Hg-MT injected rats showed no significant difference in urinary MT excretion. The magnitude in the renal accumulation of Hg is similar after the administration of Hg-MT or HgCl2, but our findings suggest that the site of epithelial injury may be different. Injury effects of Hg-MT localized mainly in the terminal portions of the proximal convoluted tubule and the initial portions of the proximal straight tubule whereas inorganic Hg caused necrosis in pars recta segments of the proximal tubule.     

Calcified left ventricular aneurysm

A 11 year old Indian boy presented with a calcified left ventricular aneurysm of unknown aetiology. The clinical, radiological and angiographic features are described. Successful surgical correction was carried out. A review of the English literature on this subject revealed that calcified cardiac aneurysm is exceedingly rare in children, only six cases having been reported to date.     

The effect of glucocorticosteroids on in vitro motility of the ureter of the sheep.

1. The effects of three glucocorticosteroids, hydrocortisone, methylprednisolone and dexamethasone, as well as two non-steroidal anti-inflammatory agents (NSAIDs) indomethacin and diclofenac sodium were tested in vitro on the spontaneously rhythmic contracting ureteral preparation of the sheep. 2. The NSAIDs and the steroids methylprednisolone (10(-7)-10(-4) M) and dexamethasone (10(-8) - 10(-4) M), dose-dependently inhibited ureteral motility. Hydrocortisone caused a cessation of spontaneous contractions only at the high concentration of 10(-4) M. 3. Pretreatment of ureteral strips with the protein synthesis inhibitor cycloheximide (10(-6) M) abolished the inhibitory action of the corticosteroids on peristalsis, consistent with the suggestion that the action of steroids on the ureter is mediated via the synthesis of the anti-phospholipase protein, lipocortin. 4. The potency of the steroids in descending order was found to be dexamethasone greater than methylprednisolone greater than hydrocortisone.     

Advanced gastric leiomyosarcoma

This is a retrospective review of twenty-two patients surgically treated for leiomyosarcoma. All but two patients had an advanced tumor of at least 8 cm size or involving contiguous structures. The most commonly performed operation was subtotal gastrectomy. The gastric resection required en bloc resection of contiguous structures in 10 patients. Fifteen patients with curative resection had a three year survival of 58 per cent. The overall group had a three year survival of 35 per cent. Advanced gastric leiomyosarcomas present a surgical challenge to complete resection, but when the procedure is accomplished the patient has a reasonable curative potential.