Surgical management of peri-ampullary tumors: a retrospective study.

BACKGROUND/AIMS: Surgical resection still remains the best treatment for patients with periampullary tumors. This study aims to present the results of surgical treatment of this disease at our center. METHODOLOGY: Between January 1995 and December 2004, 216 periampullary tumors were treated by surgical resection. The mean age was 58 years with male to female ratio 2:1. The most common symptom was jaundice (97.7%). Abdominal pain occurred in 74% of patients. Pancreaticogastrostomy was done in 183 patients and pancreaticojejunostomy in 33 patients. RESULTS: Operative mortality occurred in 7 patients (3.2%). The median survival was 22.6 months for patients with ampullary tumors and 16.6 months for patients with pancreatic head tumors. Early operative complications occurred in 33% of patients; the most common one was wound infection (11.6%), pancreatic leak (10.6%), abdominal collection (10.6%) and delayed gastric emptying (8.8%). Factors associated with increased risk of developing complications were the type of pancreatico-enteric anastomosis (pancreatic leak was more frequent with pancraticojejunostomy), soft pancreatic texture and intraoperative blood transfusion of more than 4 units. Factors associated with better survival included tumor diameter (less than 3cm), origin (ampullary), differentiation (well differentiated) and margin status (negative resection margins). CONCLUSIONS: Postoperative complications of pancreaticoduodenectomy, especially with the adoption of pancreaticogastrostomy, occur with reasonable incidence. Survival largely depends on the origin of the tumor.

216 cases of pancreaticoduodenectomy: risk factors for postoperative complications.

BACKGROUND/AIMS: Surgical resection remains the best treatment for patients with periampullary tumors. Many series have been reported with low or zero mortality, however, high incidence of complications is the rule. This study aims to present the results of pancreaticoduodenectomy and factors predisposing to postoperative complications, especially pancreatic leak, at our center. METHODOLOGY: Between January 2000 and December 2006, 216 periampullary tumors were treated by Whipple pancreaticoduodenectomy. Pancreaticogastrostomy was done in 183 patients and pancreaticojejunostomy in 33 patients. Hospital mortality and surgical complications were recorded with special emphasis on pancreatic leak. All specimens were histologically examined for the presence and origin of malignant tissue. RESULTS: The mean age was 58 years and male to female ratio was 2:1. The commonest symptom was jaundice (97.7%) followed by abdominal pain (74%). Operative mortality in 7 patients (3.2%). 71 (33%) patients developed 1 or more complications, pancreatic leak occurred in 23 (10.6%) patients, abdominal collection in 23 patients (10.6%) and delayed gastric emptying in 19 (8.8%) patients. Factors that influenced the development of postoperative complications included type of pancreaticoenteric anastomosis, pancreatic texture and intraoperative blood transfusion of 4 or more blood units. Pancreatic leak was commoner with PJ (p=0.001), soft pancreatic texture (p=0.008), intraoperative blood transfusion of 4 or more units (p<0.0001). Periampullary adenocarcinoma was found in 204 (94.4%) patients, chronic pancreatitis in 9 (4.2%) patients, 2 patients with solid and papillary neoplasm, and 1 patient with NHL (Non-Hodgkin's Lymphoma). CONCLUSIONS: Surgery is the only hope for patients with periampullary tumors. Postoperative complications after pancreaticoduodenectomy depend largely on surgical technique and can be reduced reasonably with the adoption of pancreaticogastrostomy, which is safer and easier to learn than pancreaticojejunostomy.

Resectability and prognostic factors after resection of hilar cholangiocarcinoma.

BACKGROUND/AIMS: Hilar cholangiocarcinoma, still a challenging problem for surgeons and resectional surgery, is the treatment of choice for long-term survival. In this study we tried to evaluate different prognostic factors after resection. METHODOLOGY: From January 1995 to October 2004, 440 patients with hilar cholangiocarcinoma were admitted to the Gastroenterology Surgical Center, Mansoura University, Egypt. Of these patients 73 underwent potentially curative resection giving respectability rate of 17%, and the remaining 367 patients underwent non-surgical treatment because of advanced disease, advanced cirrhosis and poor general condition. Of the 73 patients, 35 (48%) underwent localized hepatic resection and 38 (52%) patients underwent major hepatic resection. Various prognostic factors for survival were evaluated by univariate and multivariate analysis. RESULTS: Hospital mortality occurred in 8 (11%) patients. The most common postoperative complications were: bile leak, liver cell failure and wound infection 23.2%, 17.8% and 9.5% respectively. The survival rates at 1, 2, 3, 4, and 5 years were 79%, 32.6, 18.5, 137% and 13% respectively. The result of univariate analysis revealed that radicality of resection, lymph nodes status, tumor differentiation, modified Bismuth staging, underlying liver pathology, HCV viral infection, blood transfusion, preoperative serum bilirubin <10mg and CA19-9 are dependent prognostic factors. By multivariate Cox analysis radicality of resection, lymph nodes status, serum bilirubin below 10mg/dL level of CA19-9 and hepatitis viral infection were independent predictor factors. CONCLUSIONS: From this study we found that aggressive surgical procedure to obtain curative resection with preoperative serum bilirubin below 10mg and HCV infective negative especially in noncirrhotic liver may bring a better prognosis in hilar cholangiocarcinoma.

Hepatic resection in cirrhotic liver for treatment of hepatocellular carcinoma in Egyptian patients. Experience with 140 cases in a single center.

BACKGROUND/AIMS: In many centers hepatic resection is still the treatment of choice for hepatocellular carcinoma in cirrhotic liver. Several factors affect the prognosis; one of them is the extent of resection. This study retrospectively evaluates outcome after different types of hepatic resection in cirrhotic liver. METHODOLOGY: Hepatectomy was performed in 245 patients. From them, 140 patients were subjected to hepatic resection for hepatocellular carcinoma in cirrhotic liver. According to the type of resection the patients were divided into three groups (A, B and C), major resection (group A) in 79 (56.3%), segmental resection (group B) 31 (22.1%) and localized resection (group C) in 30 (21.4%). Early postoperative mortality and morbidity as well as long-term survival and recurrence were assessed. RESULTS: The overall hospital mortality rate was (8.6%) with total complications 26%, recurrence rate 32.8% and median survival was 24 months (3-120). Group A showed high incidence rate of hospital mortality, total complications and hepatic cell failure than the other two types (p>0.05). On the other hand, group C patients showed high incidence of wound infection and recurrence rate after hepatic resection than the other two types (p>0.05). At the end of the study, the median survival was 18 months (4-120), 24 months (3-48) and 24 months (3-120) for the three groups respectively without significant difference. The overall 5-year survival rate was 20%, 0% and 15.3% for the three groups respectively (p>0.05). CONCLUSIONS: Although major liver resection in cirrhotic liver has high incidence of early mortality and morbidity, it gives low incidence of recurrence and better survival in comparison with segmental and localized resection. However it has to be reserved for large tumor in good liver and early cirrhosis.

Some risk factors for hypertension in the United Arab Emirates.

A case-control study evaluated the relationship between hypertension and socioeconomic and lifestyle factors in Al-Ain city. The survey included 426 hypertensive adults aged 20-65 years attending urban and semi-urban clinics and a randomly selected sample of 436 normotensive controls. Hypertension among cases was higher for men, age 40-49 years, non-UAE nationals, urban living, currently married, having children, illiterate, administrative/professional job, living in traditional house and low income. There were significant differences between cases and controls with regard to obesity, raised cholesterol level, low physical activity and family history of heart disease, kidney disease or diabetes. Multivariate logistic regression analysis revealed that obesity, medium/high income, history of diabetes, low physical activity and having 3+ children were significantly associated with hypertension.

Some risk factors for hypertension in the United Arab Emirates

A case-control study evaluated the relationship between hypertension and socioeconomic and lifestyle factors in Al-Ain city.The survey included 426 hypertensive adults aged 20-65 years attending urban and semi-urban clinics and a randomly selected sample of 436 normotensive controls. Hypertension among cases was higher for men, age 40-49 years, non-UAE nationals, urban living, currently married, having children, illiterate, administrative/professional job, living in traditional house and low income. There were significant differences between cases and controls with regard to obesity, raised cholesterol level, low physical activity and family history of heart disease, kidney disease or diabetes. Multivariate logistic regression analysis revealed that obesity, medium/high income, history of diabetes, low physical activity and having 3+ children were significantly associated with hypertension

Studies of methyl 2-nitroimidazole-1-acetohydroxamate (KIN-804) 1: effect on free radical scavenging system in mice bearing Ehrlich ascites carcinoma.

Methyl 2-nitroimidazole-1-acetohydroxamate (KIN-804) is a 2-nitroimidazole derivative containing a hydroxamate side chain designed to enhance the radiosensitization response of hypoxic cells. The possible sensitization of tumor tissue by KIN-804 can be evaluated through investigation of the levels of the free radical scavengers; namely, glutathione (GSH) and its complex enzyme system including glutathione reductase (GR) and glutathione peroxidase (GSH-Px), as well as glucose-6-phosphate dehydrogenase (G-6-PD). Female albino mice were inoculated with Ehrlich carcinoma in the thigh. Administration of KIN-804 (i.p. 80 mg/kg body weight) was carried out 20 min before localized irradiation of 10 Gy. The data revealed that KIN-804 administration, followed or not by gamma irradiation, resulted in a significant decrease in GSH content in tumor tissues associated with inhibition in GR and G-6-PD activities. Blood GSH-Px was enhanced in tumor inoculated mice and the administration of KIN-804 returned it to the normal value. These changes were more noticeable in tumor bearing mice exposed to both KIN-804 and irradiation.

Studies of methyl 2-nitroimidazole-1-acetohydroxamate (KIN-804) 2: effect on certain antioxidant enzyme systems in mice bearing Ehrlich ascites carcinoma.

In order to decrease toxicity and/or increase radiosensitizing activity, a new 2-nitroimidazole derivative, methyl 2-nitroimidazole-1-acetohydroxamate (KIN-804), was synthesized to solve the problem of tumor hypoxia. Evaluation of the efficiency of KIN-804 was carried out through studying the antioxidant enzyme system: The superoxide dismutase (SOD), catalase and lipid peroxide levels provide a rough index of the balance between free radical generation and scavenging. Female albino mice were inoculated with Ehrlich ascites carcinoma (EAC) in the thigh. The administration of KIN-804 (i.p. 80 mg/kg body weight) was carried out 20 min before localized irradiation of 10 Gy. In general, the data revealed that KIN-804 administration, followed or not by gamma irradiation, exerted significant inhibition of SOD and catalase activities accompanied by a significant increase in lipid peroxide level in tumor-bearing mice.

Surgical treatment of hepatic hydatid cysts.

BACKGROUND/AIMS: The purpose of this study was to evaluate open surgery as a treatment for hydatid liver cysts in our locality. METHODOLOGY: Between February 1987 and September 1996, 20 patients with hepatic hydatid cysts were surgically treated. The patients were assessed by clinical examination, serologic tests, abdominal ultrasound, and computed tomography. RESULTS: Right hypochondrial pain was the most common presenting symptom (95%). The most common pathology was a solitary right lobe cyst (40%), and involvement of both the right and left liver lobes occurred in 35% of the patients. Associated visceral (splenic) cysts were diagnosed in 2 patients (10%). Intraoperatively, a cystobiliary fistula was found in 2 patients (10%). An endocystectomy was performed on 12 patients, a pericystectomy on 6 patients, and a segmental hepatic resection on 2 patients. No operative mortality was reported. The mean hospital stay was 10 +/- 5 days. Biliary leakage occurred in 2 patients (10%), a liver abscess occurred in one patient (5%), and right subphrenic collection occurred in 1 patient (5%). Recurrence was detected in 2 patients (10%). CONCLUSIONS: Surgery is still the treatment of choice for hydatid liver cysts. However, advances in pre- and intraoperative imaging techniques, together with pre- and postoperative chemotherapy (benzimidazole compounds) may offer a prospect of reducing or preventing recurrence.

Identification of a previously unknown compound as 2'-deoxycytidine found in the plasma of breast cancer patients under combined chemotherapy.

In an attempt to find an end-point for cancer chemotherapy, this study was designed to measure the adenine compounds in the plasma of breast cancer patients using HPLC with a selective reagent for adenine bases. The patients were treated by chemotherapy using cyclophosphamide, methotrexate and 5-fluorouracil. Blood was collected in tubes containing EDTA, the plasma separated by centrifugation and analysed by HPLC. An early peak due to the fluorescent derivative of an unknown compound reacted with bromoacetoaldehyde and its concentration appeared proportional to the chemotherapeutic courses of treatment. The compound in its native state without fluorescent derivatization was efficiently purified by using columns of DEAE- and CM-Sephadex. Its UV spectrum revealed maxima at 271, 280 and 272 nm in solutions of pH 7, pH 3 and pH 12, respectively. The electrophoretograms showed that it was neutral, positively and negatively charged at pH 7, pH 3 and pH 12, respectively. Thin-layer chromatograms showed that it had the same Rf as 2'-deoxycytidine (dCyd) which was confirmed by a positive reaction for deoxyribose. It was concluded that bromoacetoaldehyde formed a weakly fluorescent product with dCyd which gave rise to the early peak in the anion exchange chromatograms. From the calculation of the recovery obtained by the purification process, the cancer patients undertaking more than 12 courses had a dCyd level of approximately 20 mM while the corresponding figure in normal volunteers was less than 1 mM. These results may be useful in assessing the status of the cancer patients.

Sulfotransferase-mediated DNA binding of N-hydroxyarylamines(amide) in liver cytosols from human and experimental animals.

Characteristics of cytosolic sulfotransferase-mediated binding of carcinogenic N-hydroxyarylamines(amide) have been investigated and compared among experimental animal species and humans in vitro. Human cytosols exhibited significant sulfating activities towards 2-hydroxyamino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (N-hydroxy-Glu-P-1), N-hydroxy-2-aminofluorene (N-hydroxy-AAF) and N-hydroxy-2-acetylaminofluorene (N-hydroxy-AAF), but had no detectable activity toward 2-hydroxyamino-3-methyl-imidazo[4,5-f]quinoline (N-hydroxy-IQ). Although the extent of the covalent binding of these N-hydroxyarylamines(amide) differed significantly among individuals, clear correlations were observed among the sulfation of N-hydroxyarylamines (amide) and also with p-nitrophenol sulfation. Hepatic cytosols from mouse, rat, guinea-pig, hamster, rabbit, dog and monkey also mediated the binding of N-hydroxy-Glu-P-1, N-hydroxy-AF and N-hydroxy-AAF, while only rat cytosols showed detectable DNA binding of N-hydroxy-IQ. Among the species examined, rat showed the highest capability for activating these N-hydroxyarylamines(amides). Significant sex-related differences were detected in rat, dog and monkey for all substrates examined, except N-hydroxy-IQ. Clear correlations were observed in the animal species between N-hydroxyarylamines(amide), but not with p-nitrophenol. Using an ion-exchange chromatographic system, sulfating activity of p-nitrophenol in human livers was separated into two fractions and the PAPS-dependent DNA binding of N-hydroxy-AF was supported mainly by the later fraction. On Western blots, an immunoreactive protein was detected in these fractions using an antibody raised against rat hepatic N-hydroxy-AAF sulfotransferase. The band was also detected in human hepatic cytosols with considerable individual variation in their amounts. These results indicate the involvement of a closely related form(s) of sulfotransferase in the PAPS-mediated activation of N-hydroxyarylamines(amide) in human as well as in the experimental animal species.

An arylamine acetyltransferase (AT-I) from Syrian golden hamster liver: cloning, complete nucleotide sequence, and expression in mammalian cells.

A cDNA clone (designated hamAT101) encoding an arylamine acetyltransferase, AT-1, was isolated from a hamster liver lambda gt11 cDNA library using a specific polyclonal antibody raised against AT-1. The cloned cDNA insert consisted of 1181 nucleotides, including an open reading frame of 870 nucleotides encoding 290 amino acid (Mr 33,503). The isolated cDNA displayed high sequence similarity to those of chicken, rabbit, and human acetyltransferases. In Northern blots, the hamAT101 cDNA probe hybridized to an RNA band of 18S in the livers of both slow and rapid acetylator phenotypes. To confirm that hamAT101 cDNA encodes the monomorphic but not the polymorphic protein, the isolated cDNA was expressed in monkey kidney cells (COS-1 cells) using the vector p91023(B). A protein with a molecular weight similar to that of AT-1 was detected upon Western blotting in the 9000 x g supernatant from the transfected cells. The activity toward four different substrates of the 9000 x g supernatant was also examined. In agreement with the results of purified AT-1, the cDNA-expressed protein exhibited a high capacity for N-acetylation of 4-aminoazobenzene and 2-aminofluorene, and O-acetylation of 2-hydroxyamino-6-methyldipyrido [1,2-a:3',2'-d] imidazole, whereas no activity was found for the N-acetylation of p-aminobenzoic acid. These results, in addition to the RNA blot hybridization, indicate that hamAT101 encodes the hamster acetyltransferase AT-1.

Monomorphic and polymorphic isozymes of arylamine N-acetyltransferases in hamster liver: purification of the isozymes and genetic basis of N-acetylation polymorphism.

Two forms of cytosolic acetyltransferases, AT-I and AT-II, have been purified from hamster livers, and a comparison made of their chemical and catalytic properties and genetically expressed difference. Homogeneous AT-I and AT-II were 31 and 30 kd respectively on SDS-PAGE and catalyzed efficiently various N- and O-acetylations in their reconstitution systems. AT-I used both acetyl CoA and arylhydroxamic acids as acetyl donors, while AT-II did not utilize arylhydroxamic acids as acetyl donors. In the reconstitution system, purified AT-I, but not AT-II, catalyzed acetyl CoA-dependent O-acetylation of 2-N-hydroxyamino-6-methyldipyrido[1,2-alpha:3', 2'-d]imidazole (N-OH-Glu-P-1) and arylhydroxamic acid-dependent N-acetylation of 4-aminoazobenzene (AAB). On the other hand purified AT-II showed high activities of acetyl CoA-dependent N-acetylation of 2-aminofluorene (AF) and p-aminobenzoic acid (PABA). Polyclonal antibodies raised against AT-I inhibited cytosolic acetylations of N-OH-Glu-P-1 and AAB, and to a lesser extent of AF, while PABA N-acetylation was only marginally inhibited. Using Western blots, both AT-I and AT-II were recognized by the antibodies. AT-I was detectable in all the livers examined, and the content did not differ among the individuals (monomorphic distribution). In contrast, AT-II was distributed polymorphically, and the trimodal distribution of AT-II (high, intermediate and low) was correlated with the phenotype identified by cytosolic N-acetylations of AF and PABA (rapid, intermediate and slow). In addition, cross-mating experiments with intra- and inter-phenotype animals confirmed that hepatic AT-II isozyme is inherited by a Mendelian co-dominant trait. These results indicate that the polymorphic appearance of an acetyltransferase, AT-II, is responsible for the N-acetylation polymorphism in individual hamsters.

Enhancement by cysteinyl thiols of acetyltransferase-mediated, but not of sulfotransferase-mediated, binding of a pyrolysate-derived N-hydroxyarylamine, 2-hydroxyamino-6-methyldipyrido[1,2-a:3',2'-d]imidazole, to DNA.

The effect of thiols on the activation of a pyrolysate-derived N-hydroxyarylamine, 2-hydroxyamino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (N-hydroxy-Glu-P-1), was studied in vitro. In hepatic cytosol of rats, [3H]-N-hydroxy-Glu-P-1 bound covalently to calf thymus DNA in the presence of acetyl CoA or 3'-phosphoadenosine-5'-phosphosulfate (PAPS). The extent of the binding of N-hydroxy-Glu-P-1 in a PAPS-dependent system was decreased by the addition of 10 mM glutathione, N-acetyl-L-cysteine, 2-mercaptoethanol or dithiothreitol. However, acetyl CoA-dependent binding of N-hydroxy-Glu-P-1 was stimulated by the addition of 10 mM N-acetyl-L-cysteine (3 fold), L-cysteine (2 fold) or glutathione (1.2 fold), but not 10 mM 2-mercaptoethanol or L-methionine. After hydrolysis of the modified DNA, no difference was detected in the physicochemical properties of the nucleoside adduct formed in the acetyl CoA-supported system with and without thiols. These results indicate that thiols with a cysteine residue are able to affect the activation of carcinogenic heterocyclic arylamines selectively by the modulation of the acetyltransferase-mediated, but not the sulfotransferase-mediated, pathway.

Decrease in the metabolic activating capacities of arylamines in livers bearing hyperplastic nodules: association with the selective changes in hepatic P-450 isozymes.

The mechanism of the alteration in carcinogenic arylamine-activating capacities in livers bearing pre-neoplastic (or hyperplastic) nodules induced by the Solt-Farber protocol was investigated in relation to the changes in hepatic cytochrome P-450 isozymes. In the Salmonella mutagenesis test, the numbers of revertants induced with 2-amino-3-methylimidazo[4,5-f]quinoline and 2-aminofluorene were significantly lower in the presence of microsomes of nodule-bearing livers than of control livers. A similar tendency was also observed with another heterocyclic arylamine, 2-amino-6-methyldipyrido-[1,2-a:3',2'-d]imidazole. In Western blots using specific antibodies against 5 different forms of cytochrome P-450, hepatic contents of P-450-male (a main constitutive form) and P-450b (a main phenobarbital-inducible form) were decreased in the livers with hyperplastic nodules to 63% and 35% of the corresponding controls, while no significant decrease was observed in the contents of P-448-H (a main 3-methylcholanthrene-inducible form), P-450(6 beta-1) (testosterone 6 beta-hydroxylase) and P-450e (a phenobarbital-inducible form). In accordance with the reduction in P-450-male, capacities for microsomal 16 alpha- and 2 alpha-hydroxylations, but not 6 beta-hydroxylation, of testosterone were decreased in the livers with hyperplastic nodules. Although P-448-H has higher capacities for the activation of arylamines than does P-450-male, the hepatic content of P-450-male is more than ten-fold higher than that of P-448-H in both normal and nodule-bearing livers. These results indicate that the selective decrease in hepatic content of P-450-male is likely to be a main cause of the decrease in arylamine metabolic activating capacities in livers with hyperplastic nodules.

Acetyltransferase and sulfotransferase which activate mutagens and carcinogens through O-esterification mechanisms.

The regulatory mechanism of acetyltransferase and sulfotransferase, which are involved in the activation of carcinogenic arylamines and their N-hydroxy derivatives, has been studied. Cytosolic N-acetylation of 2-aminofluorene (2-AF) in hamster liver and skin showed tri-modal distribution in the presence of acetyl CoA, whereas no clear segregation was detected in the N-hydroxyarylacetamide-supported N-acetylation and acetyl CoA-dependent O-acetylation of N-hydroxy-Glu-P-1. From hamster livers, two forms of acetyltransferase, AT-I and AT-II, were purified and characterized to have different catalytic and chemical properties. AT-I was detectable in all the hamsters examined, but AT-II was detected only in the animals showing high rates of 2-AF N-acetylation. Cross-matings of the intra- and inter-phenotypes of three different acetylators (rapid, intermediate, and slow) indicate the genetic inheritance of the arylamine N-acetylation, which follows a Mendelian co-dominant trait. Cytosolic sulfotransferase catalyzes the activation of N-hydroxyarylamines and N-hydroxyarylacetamides through the enzymatic O-sulfonylation. The reaction often shows a sex-related difference in rats. Among three sulfotransferases isolated (HAST I, II, and PST I), the level of HASTs was correlated with the 3'-phosphoadenosine 5'-phosphosulfate (PAPS)-dependent activating capacity of N-hydroxy-2-acetylaminofluorene (N-hydroxy-AAF) in rat livers. In addition, hepatic content of HASTs was decreased by hypophysectomy and restored by the intermittent administration of growth hormone, which mimics the male secretory profile. These results indicate that the sex-related difference in secretory profile of pituitary growth hormone is a major determinant of the male-dominant sulfation in this species.(ABSTRACT TRUNCATED AT 250 WORDS)

Enzymatic acetylation and sulfation of N-hydroxyarylamines in bacteria and rat livers.

In mammalian hepatic cytosol both acetyltransferase and sulfotransferase are involved in the activation of N-hydroxy derivatives of arylamines and arylamides. The role of acetyltransferase is also shown in Salmonella, whereas no rigid evidence is provided on the role of sulfotransferase in Salmonella. In Ames mutagenesis test without S9-mix, the number of revertants of Salmonella typhimurium TA98 induced was 10-fold higher with 2-hydroxyamino-3-methylimidazo[4,5-f] quinoline (N-hydroxy-IQ) than with 2-hydroxyamino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (N-hydroxy-Glu-P-1). The extents of the binding to calf thymus DNA of N-hydroxy-Glu-P-1 were, however, 3.9 to 8.6-fold higher than that of N-hydroxy-IQ in both acetyl CoA- and PAPS-fortified rat hepatic cytosol systems. To understand the mechanism causing the apparent discrepancy between the results of the mutation and DNA binding, the activating capacities of cytosols of S. typhimurium TA98 and TA98/1,8-DNP6 strains on the binding of N-hydroxy-Glu-P-1 and N-hydroxy-IQ have been examined in comparison with those of rat livers. Although both N-hydroxyarylamines were activated by hepatic cytosols in the presence of PAPS, no significant DNA binding of these N-hydroxyarylamines was detected in the presence of PAPS and either one of the two strains of bacterial cytosols. In addition, both cytosols of TA98 and TA98/1,8-DNP6 strains showed no measurable activity on the sulfation of p-nitrophenol, suggesting no capacity for sulfotransferase-mediated activation of N-hydroxyarylamines in Salmonella. On the contrary, the extents of the acetyl CoA-dependent binding of N-hydroxy-IQ in cytosols of TA98, but not of TA98/1,8-DNP6, were respectively 6- and 9-fold higher than those in hepatic cytosols of male and female rats, although the extents of the binding of N-hydroxy-Glu-P-1 were rather higher in hepatic than in bacterial cytosols. In addition, the covalent binding of N-hydroxy-2-acetylaminofluorene to DNA was detected in hepatic, but not in bacterial cytosols, although the binding of N-hydroxy-2-aminofluorene was detectable in both hepatic and bacterial cytosols in the presence of acetyl CoA. These results indicate that the metabolic activating capacities of Salmonella and rat liver cytosols differ qualitatively, and the difference in the substrate specificity of acetyltransferase between Salmonella and rat livers may be involved, in part, in the difference of their DNA damage in bacteria and mammals.

Regulation of hepatic cortisol sulfotransferase in rats by pituitary growth hormone.

Cytosolic sulfating activities of 4-pregnen-11 beta, 17 alpha, 21-triol-3,20-dione (cortisol) to the 21-sulfate were 4 to 5 times higher in livers of female than male adult rats. The activity was decreased by administration of testosterone propionate (TP) to ovariectomized, but not to intact, female rats. In male rats, the rate of cortisol sulfation was elevated by neonatal castration and was restored in part by the administration of TP to the castrated rats. In addition, the sulfating activity in adult male rats was increased by the treatment with estradiol benzoate. Hypophysectomy almost completely decreased cytosolic cortisol-sulfating activity in male rats. The activity in hypophysectomized male rats was not increased by the treatment with hydrocortisone, TP, estradiol benzoate, or somatomedin C but was restored by the intermittent injection of human growth hormone (hGH). Further, the continuous infusion of hGH, to mimic the female secretory pattern, increased more efficiently the rate of cortisol sulfation. Hypophysectomy of female rats also decreased, but not completely, the sulfating activity. Treatment of female hypophysectomized rats intermittently with hGH had no appreciable effect, but the continuous infusion increased the activity effectively. The involvement of pituitary growth hormone in the hepatic cortisol sulfation was also supported by the experiment using neonatally glutamate-treated rats and by the observation of developmental changes in the cortisol-sulfating activity. These results indicate that pituitary growth hormone is one of the major factors regulating hepatic levels of cortisol sulfation in rats and that the higher activity in the female than the male is due mainly to the difference in the secretory pattern of growth hormone in the adult animals.