Chronic ethanol modulates delta and mu-opioid receptor expression in rat CNS: immunohistochemical analysis with quantitiative confocal microscopy.

Ethanol consumption affects levels of endogenous opioids as well as opioid receptors in both animals and humans. We studied the expression of delta (delta) and mu (mu) opioid receptors (ORs) in brain sections of adult male Sprague-Dawley rats after 2 weeks of consuming ethanol in a liquid diet, with comparisons to sections from pair-fed control animals. Immunohistochemical staining for the ORs, using selective antibodies, and quantitation of confocal images, revealed increased expression of delta-ORs in hippocampal CA1 of the chronic ethanol-treated rats. In contrast, mu-ORs decreased in their expression after ethanol treatment in multiple brain areas, including cortex, hippocampus, midbrain colliculi, striatum and nucleus accumbens. The alterations in immunoreactive OR expression may be related to reduced functional coupling of the ORs to G-proteins, as found in prior studies in several brain regions, using the same chronic ethanol diet protocol. Changes in OR expression and functional coupling in the CNS may be factors in ongoing ethanol consumption and tolerance.

Inducible expression of herpes simplex virus thymidine kinase increases sensitivity to ganciclovir but does not enhance bystander effect in breast cancer cells.

Delivery of cancer chemotherapy directly to the cancer cell has great appeal. Previous studies using adenoviral transfer of the herpes simplex virus thymidine kinase (HSV-tk) gene followed by ganciclovir (GCV) in an ascites model of breast cancer was successful in reducing tumor burden and prolonging life. However, increasing the viral dose resulted in increased toxicity and host mortality emphasizing the need for an improved therapeutic ratio. To test the hypothesis that enhancement of HSV-tk gene expression would lead to increased sensitivity to GCV and improved bystander effect, we created breast cancer cells expressing HSV-tk under the control of the inducible tetracycline promoter. Using this system, we could inducibly increase gene expression and biochemical activation of HSV-tk. These increased levels of HSV-tk decreased the IC50 to GCV nearly 50-fold. However, the bystander effect was not enhanced by increasing HSV-tk gene expression. We conclude that increased HSV-tk gene expression improves sensitivity to CCV. However, additional measures, such as increased gap junction communication, will likely be needed to enhance the bystander effect and the therapeutic efficacy of this strategy.

Hypercalciuria and recurrent urinary tract infection in Venezuelan children.

Recurrent urinary tract infection (UTI) has not been widely recognized as a clinical manifestation of hypercalciuria in children. We studied 59 children with two or more episodes of UTI, a normal urinary tract, and with hypercalciuria. Clinical manifestations were fever, dysuria, straining with micturition, hematuria, polyuria, abdominal pain, and failure to thrive. Urinary calcium/creatinine ratio was 0.36+/-0.15 mg/mg. Renal function studies included serum bicarbonate (21+/-3 mmol/l), urinary/blood PCO2 difference (11+/-11 mmHg), urinary net acid excretion (63+/-3 micromol/min per 1.73 m2), uric acid fractional excretion (13%+/-12%), and maximal urinary osmolality (920+/-236 mosmol/kg). Treatment included promotion of fluid intake, avoiding excessive salt and protein, and keeping dietary calcium between 900 and 1,200 mg/day. Potassium citrate or hydrochlorothiazide were indicated if hypercalciuria persisted. With this treatment, in 95% of the children, no further episodes of UTI occurred once normocalciuria was achieved. It is possible that hypercalciuria may play a predisposing role for recurrent UTI in children by promoting the formation of microcrystals which damage the uroepithelium. We advocate the investigation of urinary calcium excretion in children with recurrent UTI and a normal urinary tract.

Evidence that tumor necrosis factor plays a pathogenetic role in the paraneoplastic syndromes of cachexia, hypercalcemia, and leukocytosis in a human tumor in nude mice.

Recently, we have established a human squamous cell carcinoma of the maxilla (called MH-85) associated with hypercalcemia, leukocytosis, and cachexia in culture. MH-85 tumor cells caused the same paraneoplastic syndromes in tumor-bearing nude mice. We found that there was a sixfold increase in splenic size in MH-85 tumor-bearing mice. This increase paralleled tumor growth and was reversed by surgical removal of the tumor. Splenectomy in nude mice 1 wk before or 6 wk after tumor inoculation resulted in a decrease in tumor growth, and impairment of hypercalcemia, leukocytosis, and cachexia. In MH-85 tumor-bearing animals that had been pretreated by splenectomy, intravenous injection of fresh normal spleen cells caused an immediate reversal of leukocytosis, hypercalcemia, and cachexia. Since the presence of cachexia in both the patient and the mice carrying the tumor suggested tumor necrosis factor (TNF) may be overproduced, we injected polyclonal neutralizing antibodies raised against murine TNF into tumor-bearing mice. There was a rapid and reproducible decrease in blood ionized calcium, accompanied by suppression of osteoclast activity. No changes in blood ionized calcium were seen in mice injected with normal immune sera. In addition, there was an increase in body weight and decrease in white cell count. Plasma immunoreactive TNF was increased almost fourfold in tumor-bearing nude mice compared with control nude mice. Although TNF activity was undetectable in MH-85 culture supernatants, cells of the macrophage lineage, including spleen cells, released increased amounts of TNF when cultured with MH-85 tumor-conditioned media. These results suggest that splenic cytokines such as TNF may influence the development of the paraneoplastic syndromes of hypercalcemia, leukocytosis, and cachexia in these animals, as well as tumor growth. They also show that paraneoplastic syndromes may be due to factors produced by normal host cells stimulated by the presence of the tumor.

Occurrence of hypercalcemia and leukocytosis with cachexia in a human squamous cell carcinoma of the maxilla in athymic nude mice: a novel experimental model of three concomitant paraneoplastic syndromes.

Hypercalcemia and leukocytosis may occur in conjunction as paraneoplastic syndromes associated with malignant disease. Here we describe a human squamous cell carcinoma of the maxilla that was associated with hypercalcemia and leukocytosis, and also cachexia. The primary tumor was surgically removed and established in permanent cell culture. When either primary tumors or cultured tumor cells were inoculated into nude mice, the nude mice developed the same paraneoplastic syndromes as those which occurred in the patient from whom the tumor was originally derived. The plasma calcium was increased two and one-half-fold and the WBC count 30-fold, and the body weight was decreased by 45% in tumor-bearing animals. Each of these paraneoplastic syndromes was alleviated by surgical excision of the tumor, indicating that the paraneoplastic syndromes were due to a factor or factors produced by the primary tumor. The development of each of these paraneoplastic syndromes in nude mice correlated positively with the other two syndromes. We examined the organs of tumor-bearing mice and found striking histopathologic abnormalities in the bones, spleen, and liver, but no infiltration with tumor cells. The bones showed marked evidence of osteoclastic bone resorption. This model of a human tumor associated with the hypercalcemia-leukocytosis paraneoplastic syndrome, together with cachexia, should make it possible to determine the mechanisms responsible for these paraneoplastic syndromes and their relationship to each other.