Carcinogenic activity of endogenously synthesized N-nitrosobis(2-hydroxypropyl)amine in rats administered bis(2-hydroxypropyl)amine and sodium nitrite

The carcinogenic activity of endogenously synthesized N-nitrosobis(2-hydroxypropyl)amine(BHP) was investigated in male Wistar rats administered bis(2-hydroxypropyl)amine(BHPA) mixed in powder diet at a concentration of 1%, and sodiumnitrite (SN) dissolved in distilled water at concentrationsof 0.15 and 0.3%, for 94 weeks. Urinary excretion of BHP wasdetected in rats given 1% BHPA and 0.3% SN but not in the groupsreceiving either of these precursors alone. Nasal cavity, lung,esophagus, liver and urinary bladder tumors were found in animalstreated with combinations of 1% BHPA and 0.15 or 0.3% SN, suggestingthat the target organs of the endogenously synthesized BHP aresimilar to those affected when the carcinogen is administeredexogenously. The incidences of nasal cavity and lung tumorsreached 74 and 58% in rats given 1% BHPA and 0.3% SN, respectively.Tumors at sites other than target organs were only found atlevels similar to those previously reported for spontaneoustumors in male Wistars. The present results clearly indicatedthe tumor inducibility of a nhrosatable amine, BHA, throughan endogenous nitrosation by feeding to rats in conjunctionwith nitrite, and provide further suggestive evidence that endogenousnitrosations of environmental nitrosatable amines can be a potentialrisk factor in human cancer development.     

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.     

LONG‐TERM OUTCOME OF ENDOSCOPIC BALLOON DILATION IN OBSTRUCTIVE GASTROINTESTINAL CROHN's DISEASE

Background: Gastrointestinal strictures are the most often and serious complication in Crohn's disease. Because of the frequent postoperative recurrence in Crohn's disease, endoscopic therapy of gastrointestinal stricture is one of the best therapeutic options. Method: The present study sets out the results from a prospective study of endoscopic dilation therapy on 48 Crohn's disease patients with severe gastrointestinal stenoses. All patients who could not undergo endoscopic balloon dilation therapy (EBD) were operated on. Results: Long‐term success was attained in 32 of the 48 patients; cumulative avoidance of surgery after EBD was 86% at one year and 71% at three. Second, the most hazardous factor was recurrent inflammation causing restenosis. Patients who had strictures with oral luminal dilatation and patients with frequent recurrence had a tendency to be operated on. As a complication, perforation occurred in two cases (3.3%). Conclusions: EBD therapy for Crohn's stricture in the gastrointestinal tract is recommended before surgical intervention.     

Adenoid cystic carcinoma of the trachea and main-stem bronchus. A clinical, histopathologic, and immunohistochemical study

Twelve cases of adenoid cystic carcinoma of the trachea and main-stem bronchus were histologically analyzed, and the results were examined with reference to the growth pattern of the tumor and the prognosis. The tumors were histologically classified into tubular, cribriform, and solid subtypes. Three histologic grades were established: grade I, tumors with tubular and cribriform subtypes but without solid subtype; grade II, tumors with tubular and cribriform subtypes in which the solid subtype comprised less than 20% of the area; grade III, tumors in which the solid subtype comprised more than 20% of the area. Three gross infiltrating types were established: type I, entirely intraluminal; type II, predominantly intraluminal; type III, predominantly extraluminal. In most cases histologic grade correlated with gross tumor type; that is, grades, I, II, and III were grossly types I, II, and III, respectively. The tumors infiltrating along the tracheobronchial wall were of the tubular or cribriform subtype, but not of the solid subtype. In two patients who died of distant metastasis, the histologic studies revealed the solid subtype. Immunohistochemical analysis demonstrated that the tubular subtype was the most differentiated form and the solid subtype, the most undifferentiated form. The histologic subtype of adenoid cystic carcinoma of the tracheobronchial tree was an important factor in the growth pattern of the tumor and the prognosis.     

Gallium scintigraphy in patients with adult T-cell leukemia lymphoma

Gallium scintigraphy was evaluated in 25 patients with adult T-cell leukemia lymphoma (ATLL). Anterior and posterior images were obtained at 72 h after administration of 3 mCi ⁶⁷Ga-citrate using a gamma camera (Maxi-Camera 400T, General Electric Co.) with a medium energy standard parallel hole collimator. Abnormally high accumulations were observed in 17 out of 25 cases (superficial lymph node, 8; hilar and mediastinal lymph node, 7; paraaortic lymph node, 2; lung, 9; liver, 1; bone, 1). There were 10 malignant lesions detected by ⁶⁷Ga scintigraphy in 9 out of 17 cases (superficial lymph node, 1; hilar and mediastinal lymph node, 6; paraaortic lymph node, 1; liver, 1; bone, 1). White blood cell count and serum LDH levels were raised in patients with abnormally high accumulations of ⁶⁷Ga. In conclusion, ⁶⁷Ga scintigraphy seemed to be a useful examination to detect malignant lesions in patients with ATLL.     

CROMAKALIM SUPPRESSES HYPERTONIC SALINE-INDUCED RENAL VASOCONSTRICTION IN ANAESTHETIZED DOGS

1. Intrarenal arterial infusion of hypertonic saline (HS) transiently increased and then gradually reduced renal blood flow (RBF) in anaesthetized dogs. Glomerular filtration rate (GFR) but not filtration fraction decreased at the end of the infusion. 2. In the presence of a potassium channel opener cromakalim (0.3 μg/kg per min), HS infusion failed to reduce RBF; the initial increase in RBF was maintained throughout the infusion. Since cromakalim also prevented the decrease in GFR, HS infusion lowered filtration fraction. 3. The results suggest that cromakalim inhibits both pre-and postglomerular vasoconstriction induced by HS infusion.     

Reversal of alpha-methyltyrosine-induced hypoactivity by 6-(R)-5,6,7,8-tetrahydro-L-erythrobiopterin (R-THBP) in mice.

The effects of peripheral administration of 6-(R)-5,6,7,8-tetrahydro-L-erythrobiopterin dihydrochloride (R-THBP), a natural cofactor for tyrosine and tryptophan hydroxylases, were investigated in mice treated with a competitive inhibitor of tyrosine hydroxylase, alpha-methyltyrosine (alpha-MT). A subcutaneous dose of 250 mg/kg of alpha-MT decreased markedly both ambulatory activity and cerebral contents of norepinephrine, dopamine and their metabolites in mice. An intraperitoneal dose of 100 mg/kg of R-THBP, which did not alter ambulatory activities in normal mice, improved the hypoactivity in alpha-MT-treated mice. Moreover, R-THBP at intraperitoneal doses of 60 and 100 mg/kg inhibited the impairment of cerebral catecholamine metabolism induced by alpha-MT in mice. We suggest that the reversal of the alpha-MT effects by R-THBP might be due to reactivation of tyrosine hydroxylase in the central nervous system.