K-Ras gene status and expression of Ras/mitogen-activated protein kinase (MAPK) signaling molecules in ameloblastomas

BACKGROUND: To clarify the roles of rat sarcoma (Ras)/mitogen-activated protein kinase (MAPK) signaling pathway in oncogenesis and cytodifferentiation of odontogenic tumors, K-Ras gene status and expression of Ras, Raf1, MAPK/extracellular signal-regulated kinase (ERK) kinase (MEK)1, and ERK1/2 proteins were analyzed in ameloblastomas as well as in tooth germs. METHODS: Paraffin sections of 10 tooth germs and 46 benign and 6 malignant ameloblastomas were examined immunohistochemically for the expression of K-Ras, Raf1, MEK1, and ERK1/2. Frozen tissue samples of 22 benign ameloblastomas and 1 malignant (metastasizing) ameloblastoma were analyzed by direct DNA sequencing to detect K-Ras gene alteration. RESULTS: Immunohistochemical reactivity for K-Ras, Raf1, MEK1, and ERK1/2 was detected in both normal and neoplastic odontogenic epithelium, and these molecules were reactive chiefly with odontogenic epithelial cells neighboring the basement membrane. Plexiform ameloblastomas showed slightly stronger expression of these Ras/MAPK signaling molecules than follicular ameloblastomas. Keratinizing cells and granular cells showed decreased reactivity for the signaling molecules. Basal cell ameloblastomas showed slightly stronger reactivity for the signaling molecules than did the other subtypes. K-Ras immunoreactivity in malignant ameloblastomas was lower than that in dental lamina of tooth germs. Direct DNA sequencing showed a GGT to GCT point mutation at codon 12 of K-Ras gene in one ameloblastoma. Conclusion: Expression of K-Ras, Raf1, MEK1, and ERK1/2 in tooth germs and ameloblastomas suggests that Ras/MAPK signaling pathway functions to regulate cell proliferation and differentiation in both normal and neoplastic odontogenic epithelium. K-Ras gene status implied that K-Ras mutations might play a minor role in oncogenesis of odontogenic epithelium.     

Bleeding esophageal varices caused by Graves' hypervascular cervical goiter

A 65-year-old woman presented with an episode of hematemesis and a recurrent cervical goiter due to Graves' disease. The angiogram revealed bleeding esophageal varices which had developed through a drainage vein of the vascular goiter. Total thyroidectomy resulted in eradication of the esophageal varices.     

Experimental autoimmune uveoretinitis (EAU) in rats: isolation of S-antigen, EAU susceptibility of rat strains, genetic control of EAU induction, and effects of cyclophosphamide and irradiation on EAU

Highly purified S-antigen was isolated from bovine retinas by high performance liquid chromatography (HPLC), and was used to induce experimental autoimmune uveoretinitis (EAU) in various rat strains. Studies were then made of the genetic control of EAU, the effects of cyclophosphamide or irradiation on EAU, and the correlation between the EAU incidence and the serum levels of antibody to S-antigen. Lewis rats were the most susceptible to EAU followed by Wistar rats. F344 rats and BN rats were resistant to EAU. (Lewis X BN)F1 rats and (LBNF1 X Lewis) rats were susceptible to EAU, while (LBNF1 X BN) rats were resistant. These results indicate that susceptibility to EAU was inherited as an autosomal dominant trait. Treatment of rats with cyclophosphamide or irradiation (200 rad/rat) on the day before immunization markedly suppressed EAU development. On the other hand, the same dose of irradiation 7 days after the immunization did not affect the disease induction, yet the antibody levels to S-antigen were very high in the rats. In addition, BN rats resistant to EAU exhibited very high levels of antibody to S-antigen. Therefore, the antibody to S-antigen seems to play a minor role, if any, in the immunopathogenic mechanisms of EAU.     

Osteogenic sarcoma of the tibia in a patient with epidermolysis bullosa dystrophica

An osteogenic sarcoma of the tibia occurred in an eight-year-old boy with epidermolysis bullosa dystrophica hereditaria (EBDH) (Hallopeau-Siemens type). The patient had had the congenital skin disease since the time of birth. A painful swelling appeared in the proximal portion of his right tibia, which was diagnosed as osteogenic sarcoma on biopsy study. The patient died of massive pulmonary metastases and cachexia four months after the onset of the tumor. Osteogenic sarcoma in a patient with EBDH seems not to have been previously reported. EBDH has been known to be occasionally associated with squamous cell carcinoma. Whether an impairment of the patient's defense mechanism by the chronic skin disease might have enhanced the rapid progression of the associated bone malignancy is unknown.     

Spontaneous peripelvic extravasation: reports of two cases

Spontaneous peripelvic extravasation must be distinguished from spontaneous rupture of the renal pelvis in urological emergency. The literatures revealed 42 cases of peripelvic extravasation and 35 cases of rupture of the renal pelvis in Japan. Most of them were caused by urolithiasis and malignant tumors. We report 2 cases of spontaneous peripelvic extravasation caused by urolithiasis, which were successfully treated conservatively.     

Renal Effects of Multiple Infusion of Pyridoxalated-Hemoglobin-Polyoxyethylene Conjugate (PHP) Solution in Dogs

Abstract: Pyridoxalated-hemoglobin-polyoxyethylene conjugate (PHP), which is made from out-dated human red blood cells by two major chemical modifications, namely pyridoxalation and conjugation with polyoxyethylene (POE), is currently under development as a physiological oxygen carrier. This study assessed the effects of PHP-88 solution, which contains 8% (wt/vol) each of hemoglobin (Hb) and maltose, on renal function when it was infused 3 times every other day into the intact circulation of 8 dogs (5 dogs for the PHP group and 3 for the control group; 20 ml/kg for the first infusion, and 10 ml/kg each for the second and third infusions, at the rate of 2.5 ml/h/kg). Serial determinations of glomerular filtration rate (GFR) and renal plasma flow (RPF) were carried out pre- and postinfusion for up to 3 months along with measurements of blood and urine analyses, urine output rate, fractional excretion of sodium (FES), and free water clearance (C_H2O). The results showed that plasma colloid osmotic pressure (COP) elevated an average of 3.3 mm Hg (p = 0.0085), and GFR and RPF tended to increase by 13% (NS) and 38% (NS), respectively, immediately after the third infusion with PHP solution. Urine output rate increased during and after the infusion, and FES and C_H2O also increased for 24 h after the infusion in both groups. Blood urea nitrogen, serum creatinine, and serum Na⁺ concentrations were not affected greatly by the infusions, but hematocrit was decreased by 8% in the PHP group, indicating approximately a 42% expansion of plasma volume. These changes were observed to return to their preinfusion levels by 1 week postinfusion. Renal histology of the PHP group obtained at 2 weeks postinfusion revealed vacuole formation in the proximal tubules which was not associated with any pathologic changes indicative of cell death or regeneration. In 4 out of 5 dogs at 3 months postinfusion (necropsy), the vacuoles were not present. Though urinary N-acetyl β-glucosaminidase (NAG) activity had significantly increased after infusion, it returned to the preinfusion level by 1 month postinfusion. No detrimental effect of vacuoles on the assessed renal tubular functions was confirmed in the present study. The result demonstrated that multiple infusions of PHP solutions were well tolerated in normal dogs, and the observed effects were conceived predominantly attributable to the physiological response of the kidneys to an oncotic load into the circulation, which produced plasma volume expansion.     

Production of murine hybrid-hybridomas secreting bispecific monoclonal antibodies for use in urease-based immunoassays

To produce bispecific antibodies (BiAbs) for enzyme immunoassay (EIA) to replace antibody-enzyme conjugates, we developed a panel of 8-azaguanine/ouabain-resistant anti-urease variant hybridoma cell lines for use in hybridoma-hybridoma fusions. These variants represent mouse immunoglobulin subclasses IgM, IgG1, IgG2a, and IgG2b and have growth rates equal to those of the parental hybridomas. We fused an anti-urease-secreting variant hybridoma with an anti-human choriogonadotropin (hCG)-secreting hybridoma (both of IgG1 subclass) and selected the desired product with growth media containing hypoxanthine-aminopterin-thymidine (HAT) and ouabain. Over 95% of the resulting hybrids secreted anti-urease, and 60% of these secreted anti-hCG. The bispecific nature of secreted antibodies was demonstrated in a simultaneous EIA where BiAbs, hCG, and urease (EC 3.5.1.5) were incubated together in anti-hCG-coated microwells. As little as 25 int. units of hCG per liter could be reliably detected, which is equivalent to that for antibody-enzyme conjugates in EIA.     

Effect of a histidine-excess diet on a tetrahydrofolylpolyglutamate pattern in rat liver

The effect of a histidine-excess diet on the hepatic folylpolyglutamate pattern in rat was studied. Rats were fed ad libitum 9.7% casein basal diets with 0.6% methionine (controls) or the basal diets with 3.5% histidine. The average daily weight gain and the food intake in histidine-supplemented rats (His-rats) did not significantly differ from controls. The liver weight in His-rats, however, was 50% higher than controls. Hepatic methyltetrahydropteroylpentaglutamate (CH3-H4PteGlu5), and tetrahydropteroylmonoglutamate concentrations in His-rats was 5.7- and 2-fold higher than controls, respectively. The tetrahydropteroylpentaglutamate (H4PteGlu5) concentration in the His-rats was 74% lower than controls. Considering the homeostasis of folate cofactors in tissues, these results suggest that the hepatic regeneration systems for H4PteGlu5 in His-rats might be repressed and an apparent methylfolate trap might be attained rather on a pteroylpentaglutamate level than a monoglutamate level, and that the activity for catabolizing the excess histidine might exceed the regenerating activity for folate cofactors.