[A case report of combined composite valve graft replacement of the aortic root and graft replacement of the abdominal aorta]

A 55-year-old man who had both aortic root aneurysm with severe aortic regurgitation and enlarging abdominal aortic aneurysm was admitted to our hospital. We employed the combined composite valve graft replacement of the aortic root and Y-graft replacement of the infrarenal abdominal aorta at one stage operation. At the operation, median sternotomy was made and the composite graft replacement of the aortic root was performed under cardiopulmonary bypass prior to the abdominal procedure. After cardiopulmonary bypass was removed, abdominal incision was made. Although ventricular arrhythmias and mild hypotension transiently occurred when the abdominal aorta was clamped, the Y-graft replacement was also completed uneventfully, and no complication occurred postoperatively. We conclude that the combined operation of the aortic root and the abdominal aorta is clinically feasible in certain situation.

[Surgical treatment of thoracoabdominal aortic aneurysms]

Between February, 1981, and April, 1989, 20 patients underwent surgical treatment of thoracoabdominal aortic aneurysms. Most of the patients were operated under temporary external bypass. For Group I and III aneurysms without reconstruction of renal arteries, a modified Crawford's graft inclusion technique was employed to shorten abdominal visceral ischemic time. This modification consists of (1) using adjuncts to perfuse the distal aorta during aortic clamp, (2) starting the first anasistomosis from the distal end of the graft, and (3) shifting the distal aortic clamp on the graft after completing the anastomosis in order to restore abdominal visceral circulation as soon as possible. For Group III and IV aneurysms with reconstruction of renal arteries as well as celiac and superior mesenteric arteries, a modified DeBakey's procedure was employed. This modification consists of (1) using the spiral opening method, (2) doing end-to-end anastomosis at the proximal aortic site, and (3) maintaining the circulation of abdominal organs and spinal cord by using adjuncts during the anastomosis of the proximal end. There were one operative death and two hospital deaths. Paraplegia developed in two cases, one of which was a ruptured case. Renal dysfunction was not found in any case. The survivors were followed from 5 to 103 months, and there was no late death. The results suggest that our modified procedures for thoracoabdominal aortic aneurysms are useful and reliable ones.

[Indication for coronary revascularization in aortic surgery]

In order to know how to treat the coronary artery disease in scheduled aortic surgery for aortic aneurysms, a prospective study started about ten years ago using routine coronary angiography (CAG). Thoracic aortic aneurysm (TAA): CAG was performed in 73 among 143 patients and 18 had significant coronary artery stenoses (CAD), 3 of whom had angina. Concomitant CABG was performed in 2 of 4 patients requiring coronary revascularization (CR) to prevent intraoperative myocardial ischemia. Complications due to CAD were experienced in the 2 patients without CR despite of angina, while patients without angina or with CR had no complication. Abdominal aortic aneurysm (AAA): Seventy six among 150 patients had CAG, and CAD was found in 38. CR was indicated to 5 of 7 patients with angina. Complications occurred in 2 patients who had not CR in spite of angina. Patients without angina had no complication.

CONCLUSION

1) Patients who had angina are at high risk for complications due to CAD. 2) Patients with angina and necessity of cardiac arrest during aneurysmectomy should have coronary revascularization prior to aneurysmectomy. 3) Patients without angina are at low risk for myocardial ischemia in the perioperative period of aortic surgery.

Multiple classes of prostaglandin F2 alpha binding sites in subpopulations of ovine luteal cells

A cryostorage procedure was developed to provide ovine luteal cells throughout the period of seasonal anestrus. Corpora lutea obtained from midluteal phase, superovulated ewes were dispersed enzymatically. Some dispersed cells were fractionated into subpopulations by elutriation. Dimethylsulfoxide (7.5% final concentration) in Hanks' buffered saline was added to cells at 4 degrees C, and dispersed cell preparations were frozen in a programmable cell freezer and stored at -196 degrees C. After recovery from cryopreservation, cell viability and prostaglandin F2 alpha (PGF2 alpha) binding characteristics of thawed cells were not different from those of corresponding fresh cells. Additionally, thawed cells retained the capacity to attach to culture dishes and retained responsiveness of progesterone secretion to prostaglandin E2 (PGE2) and ovine luteinizing hormone (LH), although rates of progesterone secretion were attenuated in thawed compared with fresh cells. The cryopreservation procedure will prove useful to relieve constraints in utilization of ovine luteal cells arising from reproductive seasonality in sheep. Cells retrieved from cryostorage were evaluated by studying PGF2 alpha binding characteristics. From saturation analyses (increasing amounts of radiolabeled PGF2 alpha) of PGF2 alpha binding to unfractionated cells, we detected a single class of high affinity binding sites (Kd = 17.4 +/- 2.3 nM) in addition to the nonspecific binding component. Using displacement analyses (constant radiolabeled PGF2 alpha and increasing amounts of unlabeled PGF2 alpha) and unfractionated cells, we detected additional binding sites of lower affinity (Kd = 409 +/- 166 nM) as well as the nonspecific binding component. Small luteal cells obtained by elutriation, which were essentially devoid of large cell contamination, had only low affinity binding sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathological studies on nephrotoxic serum nephritis accelerated with rabbit gamma-globulin in mice

In order to characterize nephrotoxic serum nephritis accelerated with rabbit gamma-globulin in mice, histopathological studies were carried out 15 days after NTS injection, the time when increases in urinary protein and serum cholesterol and a decrease in serum albumin were apparent. Characteristic changes were widespread thickening of glomerular capillary walls and widening of mesangial areas, owing to deposits of mesangial matrixlike substances. The mesangial interposition into subendothelial areas and the resultant narrowing of the capillary lumen were shown ultrastructurally. In severely affected glomeruli, a hyaline nodular lesion was observed. Visceral epithelial cells demonstrated fusion of the foot processes, microvilli formation, occasional proliferation, and enlargement. Parietal epithelial cells proliferated, forming a cellular crescent. Based on these characteristics, it appears this nephritic model shares a common pathology with human membranoproliferative glomerulonephritis type 1 and crescentic glomerulonephritis and can be considered an appropriate model for producing severe nephritis for short periods.

[Clinical usefulness of intraoperative color Doppler sonography in the operation of the dissecting aortic aneurysm]

Dissecting aneurysm of the aorta is a serious disease with a complex and wide range of morphology. Preoperative examinations such as echo, CT, and angiography, etc, have the limits in their respective capabilities and it is not always easy to say that the morphology is sufficiently elucidated. We have investigated clinical usefulness of this method in DAA under operation. In 10 cases of DAA, We were able to easily see the stereoscopic general image of the aorta including the bloodstream by the use of Doppler's tomography. During the operation of DAA, Doppler's tomography was very useful in determining detailed surgical procedure as well as in judging effects of the operation. In conclusion, intraoperative color doppler sonography is a valuable new tool to provide information which may significantly improve the surgical result in aortic dissection.

Structural requirements for prostaglandin analog interaction with the ovine corpus luteum prostaglandin F2 alpha receptor. Implications for development of a photoaffinity probe

The capacity of structurally modified analogs of prostaglandin F2 alpha (PGF2 alpha) to inhibit binding of [3H]PGF2 alpha to receptors on ovine luteal cells was evaluated by radioreceptor assay using dispersed, viable, ovine luteal cells. Binding assays were conducted at pH 5.75, since binding to both high (Kd 17.4 +/- 2.3 nM) and low (Kd 409 +/- 166 nM) affinity sites was enhanced markedly at reduced pH. The capability to compete with [3H]PGF2 alpha for binding was evaluated for different prostaglandin analogs having modifications in the C-8 "upper" side-chain, in the cyclopentane ring, or in the C-12 "lower" side-chain. Prostaglandin J2 was a surprisingly potent competitor for binding to the PGF2 alpha receptor. Several phenyl-substituted analogs exhibited receptor-binding potency greater than or equal to native PGF2 alpha, while most other analogs had reduced capacity to compete with native PGF2 alpha for binding. Several 17-azidophenol PGF2 alpha analogs were synthesized and tested, but analogs having hydroxyl groups on the aryl ring had low affinity for receptors. However, 17-(4-azidophenyl)-18,19,20-trinor-PGF2 alpha as well as 17-(3-iodo-4-azidophenyl)-18,19,20-trinor-PGF2 alpha exhibited binding affinities that were approximately 10% of native PGF2 alpha, and the radioiodinated analogs of PGF2 alpha may be useful as probes of the PGF2 alpha receptor.

Two cases of postoperative erythroderma

Postoperative erythroderma is a rare disease of which the clinical course is almost always fatal. It is characterized by fever, skin rash, hepatic dysfunction and leukopenia, and many of the cases occur after cardiovascular surgery. We have experienced two cases of this disease which are suspected to be related to a large amount of blood transfusion. In the second case, we observed genetical mismatch of the HLA typing between the patient and his family members. This observation strongly suggests the possibility that postoperative erythroderma is a form of graft-versus-host (GVH) reaction induced by transfused lymphocytes. The reason why the patient's immunity is so suppressed as to cause GVH reaction is still unknown. Cardiopulmonary bypass and a large amount of fresh blood transfusion are suspected for immune suppression. The fact that postoperative erythroderma occurs almost exclusively in the Japanese cannot be fairly explained, either. Racial homogeneity in Japan might cause immune tolerance in blood transfusion.

[A case of hepatocellular carcinoma with a duodenal invasion from metastatic lymph node]

A 64-year-old male, who had been diagnosed as having hepatocellular carcinoma, was admitted to hospital and underwent transcatheter arterial infusion therapy. CT and US examinations revealed a large tumor with air in its center. Barium meal examination of the duodenum showed a large filling defect with a central excavation. At endoscopic examination, a dark reddish tumor was seen protruding into the duodenal lumen. A biopsy specimen from this tumor revealed a hepatocellular carcinoma. The patient subsequently died of hepatic coma following gastrointestinal bleeding. An autopsy revealed that metastatic lymph nodes had infiltrated into the adjacent duodenum. Nine previous cases of duodenal metastasis from a hepatocellular carcinoma have been reported in the Japanese literature.

Release of nucleosomes from nuclei by bleomycin-induced DNA strand scission

Mononucleosomes were released from both isolated mammalian (hog thyroid) and protozoan (Tetrahymena) nuclei by the bleomycin-induced DNA-strand breaking reaction. Trout sperm nuclei, on the other hand, were protected from the bleomycin-mediated DNA degradation. The mononucleosomes released from the bleomycin-treated nuclei contained the core histones H2A, H2B, H3, and H4; while HMG1 and HMG2 proteins, in addition to the core histones, were detected in the mononucleosomes obtained by micrococcal nuclease digestion of nuclei. HMGs, but not H1 histone, were dissociated into the supernatant by cleavage of chromatin DNA with bleomycin, whereas both HMGs and H1 were found in that fraction by digestion of nuclei with micrococcal nuclease. HMG1 and HMG2 were exclusively dissociated from chromatin with 1 mM bleomycin under the solvent condition where the DNA strand-breaking activity of the drug is repressed. These observations suggest the possibility that bleomycin preferentially binds to linker DNA regions not occupied by H1 histone in chromatin and exclusively dissociates HMG proteins and breaks the DNA strand. The results of the effects on bleomycin-induced DNA cleavage of nuclei of various drugs including polyamines, chelating agents, intercalating antibiotics such as mitomycin C or adriamycin, and radical scavengers are also presented.

[Aneurysm of the left sinus of Valsalva producing obstruction of the left main coronary artery and aortic regurgitation]

A 50-year-old male was admitted with dyspnea on exertion and palpitation. On physical examination, a grade 2/6 aortic regurgitant murmur was heard at the left sternal border. A chest roentogenogram showed an oval shadow on the left cardiac border. Digital subtraction angiogram, aortogram and coronary arteriogram revealed an unruptured-large aneurysm of the left sinus of Valsalva, which compressed the left main coronary artery and produced aortic regurgitation. Surgical correction consisted of obliteration of the orifice of the aneursym with woven Dacron graft patch, aortic valve replacement using SJM23A, and a saphenous vein bypass from the ascending aorta to the left anterior descending coronary artery. Postoperative studies showed complete obliteration of the orifice of the aneurysm, a patent aorto-coronary bypass graft and no perivalvular leakage. This aneurysm was considered congenital in origin, because of no inflammatory and infectious evidence, negative serologic test for syphilis and no aneurysmal dilatation of the ascending aorta.

[The prognosis and the surgical indications of DeBakey type III dissecting aortic aneurysm]

In order to determine the indications of operation for dissecting aortic aneurysm of DeBakey type III, therapeutic results obtained from 60 cases (11 with type IIIa and 49 with type IIIb) treated at our department during the 19-year period until the end of 1984 were analyzed as well as their distant prognosis. Since 12 cases (20%), who visited our department during the acute phase, were all abated to the subacute phase by hypotensive treatment, and since only one of the 12 cases died from pneumonia 5 weeks after the onset, it was thought that the operation during the acute phase is in most cases not necessary. We applied operation when there was a large false lumen, a regional protrusion, rupture or impending rupture. Out of the 60 cases, 25 (42%; 7 with type IIIa and 18 with type IIIb) underwent operation, and 3 of them (12%), including one ruptured case during the chronic phase, died due to the operation. Among cases with type IIIa, a non-operated case died of a related cause (rupture) during distant period, but none of operated cases died. Among discharged cases with type IIIb, 4 of 16 operated cases (25%) died of related causes during distant periods. This mortality did not differ from that of non-operated cases; namely, 8 of 30 non-operated cases died (27%). A 5-year survival rate was also identical between the non-operated and operated cases with type IIIb; namely, about 50% in the 2 groups.(ABSTRACT TRUNCATED AT 250 WORDS)

A clinical study of cerebral circulation during extracorporeal circulation

The objective of this study is to clarify the relationship of cerebral blood flow to extracorporeal circulation flow and mean arterial pressure during nonpulsatile extracorporeal circulation under moderate hypothermia. Cerebral blood flow was determined by an argon saturation and desaturation method after that of Pevsner and colleagues with a mass spectrometer in 21 adult patients undergoing cardiac operations. Cerebral blood flow was 25, 33, 35, and 42 ml/100 gm/min, ranging from 19 to 50 ml/100 gm/min, at extracorporeal circulation flow rates of 40, 50, 60, and 70 ml/kg/min, respectively. Cerebral blood flow increased proportionally to extracorporeal circulation flow. Cerebral blood flow scattered almost transversely to mean arterial pressure and was 31 ml/100 gm/min in a hypotensive group (mean arterial pressure 34 to 50 mm Hg) and 34 ml/100 gm/min in another group (mean arterial pressure 51 to 94 mm Hg). Mean arterial pressure did not significantly influence cerebral blood flow. Cerebral oxygen consumption did not remarkably decrease and remained in the reasonable range when cerebral blood flow was 23 to 40 ml/100 gm/min. Subsequently, we assumed that the average cerebral blood flow value of 25 ml/100 gm/min at an extracorporeal circulation flow rate of 40 ml/kg/min also would be in the safe range. All of the patients are living without cerebral complications. We conclude that (1) cerebral blood flow was extracorporeal circulation flow dependent and (2) cerebral blood flow in the safe range was maintained even in the hypotensive range, provided the extracorporeal circulation flow rate was 40 ml/kg/min or higher.

Prostaglandin photoaffinity probes: synthesis and biological activity of azide-substituted 16-phenoxy- and 17-phenyl-PGF2 alpha prostaglandins

The development of a prostaglandin PGF2 alpha photoaffinity probe led to the synthesis and biological evaluation of azide-substituted 17-phenyl-18,19,20-trinorprostaglandin F2 alpha and 16-phenoxy-17,18,19,20-tetranorprostaglandin F2 alpha derivatives. Two approaches for the preparation of iodinated versions of these prostaglandins were evaluated: (1) iodination of a phenyl azide bearing an activating hydroxyl group and (2) iodination of an aniline precursor to the phenyl azide group and subsequent conversion of the aniline to the phenyl azide. In the first approach, 17-(4-azido-2-hydroxyphenyl)-18,19,20-trinorprostaglandin F2 alpha, 16-(5-azido-3-hydroxyphenoxy)-17,18,19,20-tetranorprostaglandin F2 alpha, and 16-(4-azido-2-hydroxyphenoxy)-17,18,19,20-tetranorprostaglandin F2 alpha were prepared by using the Corey synthesis, but were biologically inactive presumably as a result of the hydrophilic phenolic hydroxyl group. In the second approach, the iodination of a 17-(4-aminophenyl)-18,19,20-trinorprostaglandin F2 alpha derivative delivered 17-(4-azido-3-iodophenyl)-18,19,20-trinorprostaglandin F2 alpha, which exhibited competitive binding with natural [3H]PGF2 alpha to ovine luteal cells and to plasma membranes of bovine corpora lutea. [125I]-17-(4-Azido-3-iodophenyl)-18,19,20-trinorprostaglandin F2 alpha was utilized in a preliminary photoaffinity cross-linking experiment.

A functioning intrapericardial paraganglioma (pheochromocytoma)

A patient with a functioning intrapericardial paraganglioma (pheochromocytoma) that was located at the root of the aorta overlying the right coronary artery and adherent to the right ventricular wall is reported. The tumour was successfully removed under total cardiopulmonary bypass without inducing cardiac arrest.

Evidence for immunosuppression by high-dose gammaglobulin

High-dose immunoglobulin therapy, which is useful for the treatment of idiopathic thrombocytopenic purpura, autoimmune neutropenia, childhood epilepsy, and Kawasaki disease is postulated here to act by immunosuppressing the patients. Evidence provided here shows that the immunoglobulin inhibits phytohemagglutinin (PHA) stimulation, mixed lymphocyte culture (MLC) response, natural killer assay, antibody-dependent cell-mediated cytotoxicity, and cell-mediated lympholysis. These assays were all inhibited by IgG concentrations that exceeded normal levels by 1.5-2 times. It is also shown that Fc fragments were 100-1000 times more effective than intact IgG in inhibiting the PHA and MLC responses. Thus, it is likely that the Fc portion of immunoglobulin functions as an inhibitor of cellular immunity.

DNA strand scission by enzymatically reduced mitomycin C: evidence for participation of the hydroxyl radical in the DNA damage

Phage DNA, as well as plasmid and mammalian DNA's, were exposed to a superoxide and hydroxyl radical-generating system containing NADPH-cytochrome P-450 reductase and mitomycin C, both with and without added Fe3+-ADP, in phosphate buffer at pH 7.5. The generation of superoxide (O2-.) and hydroxyl (.OH) radicals in the system was demonstrated by using ESR spectrometry with N-tert -butyl-alpha-phenylnitrone (PBN) as a spin trapping agent. Only the lambda DNA isolated after exposure to the O2-./.OH-generating system containing many lower molecular weight DNA fragments indicating DNA strand breaks. This breakage was completely inhibited by a .OH radical scavenger (sodium benzoate) and by catalase, but only slightly by superoxide dismutase. Thyroid and plasmid DNA's were both cleaved when exposed to the O2-./.OH-generating systems. It is suggested that the mechanism of DNA scission by mitomycin C described here closely resembles that induced by the anthracycline drugs.

Fluorine-containing amino acids and their derivatives. 4. Synthesis and antibacterial activity of threo and erythro 1-fluorodehydroxylated chloramphenicol analogues

Both threo and erythro 1-fluorodehydroxylated chloramphenicol analogues were synthesized and tested for antimicrobial activity. None showed antibacterial or antifungal activity, clearly demonstrating that substitution of the secondary hydroxyl group with fluorine abolishes the antibacterial activity of the parent compound, chloramphenicol. This finding sharply contrasts with that of previous workers, in which fluorination of the 3-hydroxyl group enhanced antibacterial activity against many chloramphenicol-resistant strains.

Carcinogenic activities of hydroxymethyl derivatives of 4-(dimethylamino)azobenzene in the liver of rats, mice, and hamsters

The carcinogenic activity of 3'-hydroxymethyl-N,N-dimethyl-4-aminoazobenzene (3'-CH2OH-DAB) was studied in Sprague-Dawley rats of both sexes, male ddy mice, and male Syrian golden hamsters. The activity of 2'-CH2OH-DAB and 4'-CH2OH-DAB was studied in male Sprague-Dawley rats. Azo dyes were given in the diet at a concentration of 0.064% for 3 months followed by a stock diet for 1 month; animals were sacrificed 4 months after beginning of the experiment. Liver hyperplastic nodules developed in all 8 male rats (100%) and in all 10 female rats (100%) which received 3'-CH2OH-DAB and in 7 out of 12 male rats (58%) which received 2'-CH2OH-DAB. Hepatocellular carcinomas were produced in 1 out of 8 male rats (13%) and in 1 out of 10 female rats (10%) receiving 3'-CH2OH-DAB. No hepatic lesions were observed in rats receiving 4'-CH2OH-DAB and in mice and hamsters receiving 3'-CH2OH-DAB. These results indicate that a carcinogenic effect of 3'-CH2OH-DAB and 2'-CH2OH-DAB could be detected in rats.

Normalized natural killer (NK) cell activity in long-term remission of acute leukaemia

NK cell activity was studied in 28 cases of acute leukaemia in remission. It was found that patients in long-term remission for 5 years or more had normal NK cell activity but those in remission for less than 5 years had significantly lowered activity. This suggests that patients with acute leukaemia had not been constitutionally deficient in NK cell activity. Low activity was augmented but not fully restored by interferon pretreatment in vitro. Therefore, the low NK cell activity observed during remission is not solely attributable to inadequate secretion of interferon in the host. It is suggested that the production of NK cells in bone marrow is impaired, or the function of NK cells is suppressed, by the leukaemia itself or by chemotherapeutic agents. Increased consumption of NK cells is also a possibility.

Clinical results of cardiopulmonary bypass with selective cerebral perfusion for aneurysm of the ascending aorta and the aortic arch

The purpose of this report is to describe our experience using cardiopulmonary bypass with selective cerebral perfusion in 10 patients whose aneurysms required cross-clamping the aorta and brachiocephalic vessels. Cerebral perfusion was carried out with individual roller pumps. Flow rate was 11.2 +/- 4.8 ml per kilogram of body weight per minute to the right axillary artery, 8.5 +/- 1.0 to the right common carotid artery, 7.0 +/- 2.0 to the left common carotid artery, and 3.9 to the left subclavian artery. All the patients came off bypass smoothly, and only 3 required small amounts of inotropic agents postoperatively. One patient with mycotic aneurysm died in the fourth postoperative week of massive bleeding due to disruption of the suture line. No cerebral complications were experienced. The operative results of this series suggest the usefulness of cardiopulmonary bypass with selective cerebral perfusion, and reasonably favorable outlook for patients with aneurysm involving the aortic arch and the ascending aorta.

[Experimental studies on iron deficiency anemia in pregnant rat and its feto-maternal influence (author's transl)]

The purpose for this experiment is to know the influence on fetus of the iron deficient pregnant rat, fed with iron deficient diet. On day 21st of gestation in normal pregnant rat, RBC, Ht and non-hemin iron of maternal liver are significantly lower than those of non-pregnant, but in iron deficient pregnant, those indexes as well as Hb are slightly but further decreased. We studied ferrokinetics with 59Fe specific binding transferrin by 59Fe-NTAmethod. Plasma iron disappearance rate T (1/2) was 97 minutes in non-pregnant, 25 minutes in normal pregnant and 22 minutes in iron deficient pregnant rat. It is significantly faster in pregnant than non-pregnant rat, but there was little difference between normal and iron-deficient pregnant rat. The mean body weight of fetuses was 4.5g in iron deficient pregnancies against significantly higher 5.2g in normal pregnancies. Hb and non-hemin iron of fetal liver were significantly decreased in iron deficient group. These result suggest that maternal iron utilization must be maintained at minimum level, so that supply of iron to fetus can be kept at maximum level. When pregnant rat is fed with iron deficient diet, there are some adverse influences on fetus, especially of intrauterine fetal growth retardation.

Tumorigenicity of 3'-hydroxymethyl, 3'-formyl, and 3'-carboxy derivatives of 4-(dimethylamino)azobenzene in rat liver

Male Sprague-Dawley rats were fed a cube diet containing 2.51 mmol/kg of 3'-methyl-4-(dimethylamino)azobenzene (3'-Me-DAB), 3'-CH2OH-DAB, 3'-CHO-DAB, or 3'-COOH-DAB (at a level equivalent to 0.06% 3'-Me-DAB in the diet) for a period of 1 to 3 months. Almost all the livers of rats given 3'-CH2OH-DAB for a period of 2 to 3 months or 3'-Me-DAB for 3 months showed marked cirrhosis macroscopically. The common histological findings were cholangiofibrosis with or without markedly atypical bile ducts. Moreover, one hepatocellular carcinoma was found in the liver of a rat given 3'-Me-DAB and one in the liver of a rat given 3'-CH2OH-DAB for 3 months. On the other hand, 3'CHO-DAB and 3'-COOH-DAB did not induce these changes (including neoplastic nodules) at all. Consequently, 3'-CH2OH-DAB, like 3'-Me-DAB, was found to be a hepatocarcinogen.

Carcinogenicity of 3'-hydroxymethyl-N,N-dimethyl-4-aminoazobenzene in rat liver

Male Sprague-Dawley rats were fed a cube diet containing 2.51 mmol/kg 3'-hydroxymethyl-N,N-dimethyl-4-aminoazobenzene (3'-CH2OH-DAB) for a period of 1 or 3 months. (This is the molar equivalent of 0.06% 3'-Me-DAB in the diet). The oral administration of 3'-CH2OH-DAB for 3 months resulted in a high incidence of liver tumors at 6 months and the 1 month feeding also caused the development of liver tumors. Histologically, the tumors were cholangiocellular carcinomas and hepatocellular carcinomas. The development of tumors in other sites was not seen. Consequently, 3'-CH2OH-DAB, a recently identified metabolite of 3'-Me-DAB, is a potent hepatocarcinogen.