Catalytic properties of rabbit kidney fatty acid omega-hydroxylase cytochrome P-450ka2 (CYP4A7).

We have examined in detail the substrate specificity of a rabbit kidney fatty acid omega-hydroxylase, designated cytochrome P-450ka2 (CYP4A7). The hydroxylation products were identified as omega- and (omega - 1)-hydroxy fatty acids mainly using gas chromatography-electron impact mass spectrometry. [1] Straight-chain saturated fatty acids ranging from 10 to 19 carbons were effectively hydroxylated at the omega- and (omega - 1)-position. The ratios of omega- to (omega - 1)-hydroxylation activity decreased with increasing the carbon chain length of fatty acids. [2] Both isomyristate and anteisomyristate, and isopalmitate were hydroxylated several fold more rapidly than myristate and palmitate, respectively, with iso-branched chain fatty acids being hydroxylated at the omega-position solely. [3] Both palmitoleate and palmitoelaidate, and both oleate and elaidate were hydroxylated much more rapidly than palmitate and stearate, respectively. [4] Linoleate, gamma-linolenate, and arachidonate were also excellent substrates for this enzyme. [5] Prostaglandin (PG) A1 and PGA2 were efficiently hydroxylated at the omega-position solely, with PGE1 and PGE2 being much less active. [6] Arachidonic acid not only showed a Km value significantly lower than those for lauric acid, gamma-linolenic acid and PGA1, but also it is a potent competitor for lauric acid and PGA1, showing a very high affinity for the enzyme. It is possible that arachidonic acid is the physiological substrate for kidney P-450ka2.

Protection by oral pretreatment with taurine against the negative inotropic effects of low-calcium medium on isolated perfused chick heart.

Chicks were given taurine by mouth using a cannula pushed down into the oesophagus. This treatment had protected the heart, when subsequently removed, against the decline of contractile force in the perfused heart brought about by low-calcium media. A small but statistically significant increase in taurine concentration occurred in the ventricular tissue of such pretreated hearts. In contrast, pretreatment with taurine did not affect ventricular calcium level. Addition of taurine (3 to 100 mmol . litre-1) into the perfusing solution did not alter the cyclic AMP level in the control perfused hearts, and failed to induce slow channel action potentials in hearts whose fast Na+ channels had been inactivated by high K+ (25 mmol . litre-1). However, taurine perfusion produced a significant positive inotropic action which became stable after 5 to 10 min of exposure.

Mechanism of the protective action of taurine against isoprenaline induced myocardial damage.

The effect of the sulphur amino acid, taurine, on the biochemical changes induced by a toxic dose of isoprenaline was examined in chick hearts. Isoprenaline treatment (80 and 240 mg.kg-1 subcutaneously twice a day for four days) caused a dose dependent increase in heart to body weight ratio. Isoprenaline administration induced a substantial accumulation of calcium and caused a profound decrease of adenosine triphosphate content and creatine phosphokinase activity in the myocardium. A pronounced increase in lipoperoxide and decrease in phospholipid and reduced glutathione concentrations were also seen. Oral administration of taurine (200 mg.kg-1 for seven days) partially protected against these changes induced by isoprenaline. It is suggested that the beneficial effect of taurine may be due in part to inhibition of lipoperoxide formation and calcium accumulation and to protection against the deterioration of membrane phospholipids.

Acute haemodynamic effect of taurine on hearts in vivo with normal and depressed myocardial function.

The acute haemodynamic effects of taurine were studied in normal and in beta blocker (propranolol) or calcium antagonist (diltiazem) treated rabbits and in rabbits with experimentally produced chronic aortic regurgitation. The administration of taurine (25 mg.kg-1) did not affect heart rate and left ventricular end diastolic pressure but produced significant increases in left ventricular dP/dtmax, cardiac output, and left ventricular systolic pressure in control hearts, indicating that intravascularly administered taurine substantially increased cardiac performance. In propranolol (1 mg.kg-1) treated rabbits taurine significantly improved left ventricular dP/dtmax and cardiac output, which were previously depressed by propranolol. Taurine had the same effect on diltiazem (1 mg.kg-1) treated rabbits. In rabbits with aortic regurgitation a bolus injection of taurine improved cardiac performance. Continuous infusion of taurine (100 mg.h-1) also produced a significant increase in left ventricular dP/dtmax. These results suggest that taurine has a unique action as an inotropic agent and that it may be useful in the treatment of patients with congestive heart failure.

Taurine modulates ion influx through cardiac Ca2+ channels.

The effects of taurine on the inward Ca2+ current (ICa) were investigated by means of the whole-cell voltage-clamp technique in isolated single guinea pig ventricular myocytes. ICa were elicited by 200-ms test pulses from a conditioning holding potential of -45 mV to various test potentials at a rate of 0.5 Hz. Taurine (10-20 mM) had different effects on ICa, depending on the extracellular Ca2+ concentration [( Ca]o). A small stimulatory effect of taurine was found in low [Ca]o (0.8 mM), and a small inhibitory effect was found in high [Ca]o (3.6 mM). Taurine had no significant effect on ICa in normal [Ca]o (1.8 mM). Such dual effects on ICa may explain the various effects reported for taurine especially its dual inotropic actions on cardiac muscle depending upon [Ca]o. Thus, taurine acts in a manner to keep ICa relatively constant. Taurine increased the resting potential irrespective of [Ca]o, suggesting that, in addition, taurine increased K+ conductance and/or ion exchange systems such as the Na/Ca and Na/K exchange.

Isolation of a new form of cytochrome P-450 with prostaglandin A and fatty acid omega-hydroxylase activities from rabbit kidney cortex microsomes.

Two different forms of cytochrome P-450, highly active in the omega-hydroxylation of prostaglandin A, and the omega- and (omega-1)-hydroxylation of fatty acids (P-450ka-1 and P-450ka-2), have been purified from kidney cortex microsomes of rabbits treated with di(2-ethylhexyl)-phthalate. On the basis of the peptide map patterns and NH2-terminal amino acid sequence, P-450ka-1 was determined to be a new form of omega-hydroxylase cytochrome P-450, whereas P-450ka-2 is identical to P-450ka reported earlier. The first 20 NH2-terminal amino acid sequence (ALNPTRLPGSLSGLLQVAGL) and (ALSPTRLPGSFSGFLQAAGL) of P-450ka-1 and P-450ka-2 showed 90 and 80% homology with that of the lung prostaglandin omega-hydroxylase, respectively, suggesting that these three cytochromes P-450 are members of the same omega-hydroxylase cytochrome P-450 gene family.

Therapy of congestive heart failure with orally administered taurine.

The clinical efficacy of 2 gm BID of oral taurine (2-aminoethane sulfonic acid) was studied in 24 patients with congestive heart failure (CHF). We expressed the severity of CHF by a score based on clinical signs and symptoms and on roentgenographic data. The maximum possible score, corresponding to the worst CHF, was 23 points. How much the 24 patients improved after receiving taurine for four or eight weeks was estimated by the difference between their pretreatment and posttreatment scores. In 19 of the 24 patients, taurine was effective. In the group as a whole, mean (+/- SEM) scores fell significantly, from 7.3 +/- 0.6 before treatment to 4.4 +/- 0.5 after treatment. Thirteen of the 15 patients who were designated as New York Heart Association (NYHA) functional class III or IV before receiving taurine could be designated as class II after they completed the study. This pilot study should prompt further investigation into the possible use of taurine in the treatment of patients with CHF.

Kainic acid-induced substantia nigra seizure in rats: behavior, EEG and metabolism.

RATIONALE: In order to clarify the role of substantia nigra pars reticulata (SNr) upon the development of epileptic seizure, kainic acid (KA) was injected into a unilateral SNr. MATERIALS AND METHODS: Wistar rats weighing 250-350 g were used. A stainless-steel cannula and depth electrode were inserted stereotaxically into the left substantia nigra pars reticulata (SNr). At 7 days after surgery, 1.0 microg of KA was injected into the left SNr. Experiment 1: In eight rats, behavior and electroencephalograms (EEG) were continuously recorded for about 30 h, and intermittently monitored following 1 month. Experiment 2: Two hours after KA injection into SNr, rats demonstrated status epilepticus. Then, 100 microCi/kg of [(14)C]2-deoxyglucose (2-DG) was intravenously injected in seven rats, and the rats were processed for autoradiographic study. RESULTS: Changes in behavior and EEG: On EEG, a secondary generalized seizure status was observed at about 70 min after KA injection. In video, limbic seizure manifestations such as salivation were observed as a initial symptom and followed by rolling and generalized tonic seizures. [(14)C]deoxyglucose autoradiographic study demonstrated increased local cerebral glucose metabolism in the medial and lateral septal nucleus, substantia nigra, hippocampus, parietal cortex, piriform cortex, medial and lateral geniculate nucleus, anterodorsal, lateral and ventral nucleus of the thalamus, amygdala and midbrain reticular formation. SUMMARY: The result suggested that the substantia nigra played an important role in the secondary generalization in the substantia nigra seizure model due to the decreased function of the GABAergic projection system induced by an excessive epileptic excitation of SNr.

Protective effect of taurine against decline of cardiac slow action potentials during hypoxia.

The effect of taurine on cardiac slow action potentials (APs) during hypoxic superfusion was studied in isolated guinea-pig papillary muscles. Ca2+-dependent slow APs were induced by isoproterenol (10(-6) M) in preparations which were voltage-inactivated by high (25 mM) K+. Although taurine had no effect on the slow AP parameters during normoxia, taurine (10 mM) superfusion significantly protected against the decline of slow APs produced by hypoxia. Taurine also restored slow APs that had been previously abolished by hypoxia. Therefore, taurine exposure may protect the Ca2+ slow channels which are inhibited or blocked by hypoxic conditions.

Trapidil stimulation of slow Ca2+ current in cardiac muscle.

The effect of trapidil, a coronary vasodilator and positive inotropic agent (associated with elevated tissue cyclic AMP levels due to phosphodiesterase inhibition), was examined on the electrophysiological properties of cardiac muscle. Specifically, the trapidil was tested for its ability to induce slow action potentials (APs), and to affect the maximum upstroke velocity (+Vmax) of the slow APs in the ventricular myocardial cells of isolated perfused chick hearts. The effect of trapidil on the contractions accompanying the slow APs and on the tissue cyclic AMP levels was also examined. To study the slow channels exclusively, the fast Na+ channels were voltage-inactivated by elevated (25 mM) K+. In this condition of functional removal of the fast channels, the hearts could not be excited even by intense electrical stimulation. It was found that trapidil (10(-4)--10(-3) M) induced slow APs accompanied by contractions. Elevation of the trapidil concentration produced dose-dependent increases in +Vmax, dT/dt (first derivative of developed tension) and cyclic AMP. These effects of trapidil were not affected by propranolol, suggesting that they were not mediated by beta-adrenergic receptors. These results support the hypothesis that intracellular cyclic AMP levels regulate the number of available slow channels, thereby controlling contractile force in the heart muscle via the Ca2+ influx mediated by slow channels.

Mechanism of direct cardiostimulating actions of hydralazine.

The vasodilator, hydralazine, was reported to also exert a direct positive inotropic effect on the myocardium at high concentrations. In the present study we investigated the mechanism of this positive inotropic action by using the ventricular myocardium of isolated perfused chick hearts. Hydralazine (10(-3) M) enhanced contractile force and heart rate, and elevated the myocardial cyclic AMP level. To study the Ca2+-dependent slow action potentials, the fast N+ channels were voltage-inactivated with elevated K+ (25 mM), resulting in a loss of electrical excitability. Hydralazine (10(-4) M) rapidly (less than 3 min) allowed the generation of slow action potentials and accompanying contractions by electrical stimulation. These effects of hydralazine were only partially prevented by propranolol. The results suggest that the increase of myocardial contractility produced by hydralazine is the result, at least in part, of a direct effect on the myocardium to increase Ca2+ inflow. The increased Ca2+ influx and inward slow current is due partly to activation of beta-adrenoceptors, with resultant elevation of cyclic AMP, and partly to another mechanism.

Plasma endothelin levels during myocardial ischemia and reperfusion.

Endothelin, an endothelium-derived vasoconstrictive peptide, has a strong potency of coronary artery constriction. However, the role of endogeneous endothelin under pathophysiological conditions has not yet been known. In this study, we examined plasma endothelin concentration in dogs with myocardial ischemia and reperfusion. Anesthetized open-chest dogs underwent either 45 minutes occlusion of the left anterior descending coronary artery followed by 3 hours reperfusion, or 4-10 hours of continuous occlusion. Plasma concentration of endothelin from the central vein was measured by the highly sensitive enzyme-immunoassay. Plasma endothelin concentration increased 2.2-fold with the peak level at 60 minutes after release of the ligated artery, but occlusion per se caused no remarkable change. These data suggest that reperfusion of the occluded artery might be needed to increase the plasma concentration of endothelin in case of myocardial infarction.

Taurine's possible protective role in age-dependent response to calcium paradox.

When hearts were reperfused with Ca++ after a short period of Ca++-free perfusion, irreversible loss of electrical and mechanical activity was observed. This phenomenon, first described by Zimmerman and Hulsmann, was termed the "calcium paradox". Chizzonite and Zak recently reported that rat hearts exhibited an age-dependent response in a calcium paradox model. The taurine (2-aminoethanesulfonic acid) content of hearts in the newborn animal is high, and decreases rapidly during the first few days of life. The present experiments were performed to test whether the myocardial taurine content was closely linked to an age-dependent response in the calcium paradox model, using post-hatched chicks. The mechanical dysfunction of the heart was much more severe in 9-day-old post-hatched chicks than in 2-day-old chicks when the hearts were subjected to the calcium paradox. Myocardial taurine content was lower in the 9-day-old chicks than in the 2-day-old chicks. The age-related response to the calcium paradox was partially protected by oral pretreatment with taurine, and there was a small increase in myocardial taurine level. It is proposed that myocardial taurine is one factor in the protection against the calcium paradox phenomenon.

Locoregional immunotherapy of malignant ascites by intraperitoneal administration of OK-432 plus IL-2 in gastric cancer patients.

The clinical efficacy of intraperitoneal administration of OK-432 plus interleukin-2 (IL-2) for treating malignant ascites was evaluated in gastric cancer patients. Ten KE of OK-432 and 200,000 Jurkat units of IL-2 were intraperitoneally administered in tandem in the order given on alternate days at paracentesis. Of the 22 evaluable patients, 18 (81%) developed complete or partial responses, showing a cytologic disappearance of cancer cells and decrease of ascites. More than 50% of the patients obtained positive responses within 2 weeks after the initial administration of the drugs. Improvements of performance status and clinical symptoms such as abdominal fullness, followed by restoration of oral food intake and prolongation of survival time were observed in responders treated with OK-432 plus IL-2. Flow cytometric analysis demonstrated a predominant increase of the CD3+CD4+ cells, especially of the CD4+CD45RA- subset in the peritoneal cavity of the responders. Cytotoxicity assay after negative selection of the CD4+ cells with the antibody and complement revealed that the CD4+ subset possessed cytotoxic activity against autologous tumor cells. The results suggest that intraperitoneal administration of OK-432 plus IL-2 may not be only a practical but also an effective protocol for treating malignant ascites in gastric cancer patients.

Effects of methyl linoleate hydroperoxide and hydrogen peroxide on N-nitrosation of dimethylamine.

The effects of methyl linoleate hydroperoxide and hydrogen peroxide on the N-nitrosation of dimethylamine were investigated. Hydrogen peroxide inhibited the formation of N-nitrosodimethylamine by the reaction of dimethylamine and nitrite in citrate buffer (pH 3-5). The inhibitory effect was due to the loss of available nitrite by quantitative conversion into nitrate. The formation of N-nitrosodimethylamine from the reaction of dimethylamine and nitrous acid in chloroform was effectively inhibited by methyl linoleate hydroperoxide. The inhibitory effect of the hydroperoxide was much greater than that of methyl linoleate. The loss of nitrous acid from the reaction mixture was due to the conversion of nitrous acid into nitric acid and the formation of two adducts, both of which contained nitrogen and had peroxide and carbonyl or carbonyl-liberating functions. It is suggested that unsaturated fatty acids and lipid hydroperoxides are effective inhibitors of nitrosamine formation.

Therapeutic effect of taurine in congestive heart failure: a double-blind crossover trial.

In a double-blind, randomized, crossover, placebo-controlled study, we investigated the effects of adding taurine to the conventional treatment in 14 patients with congestive heart failure for a 4-week period. Compared with placebo, taurine significantly improved the New York Heart Association functional class (p less than 0.02), pulmonary crackles (p less than 0.02), and chest film abnormalities (p less than 0.01). A benefit of taurine over placebo was demonstrated when an overall treatment response for each patient was evaluated on the basis of clinical examination (p less than 0.05). No patient worsened during taurine administration, but four patients did during placebo. Pre-ejection period (corrected for heart rate) decreased from 148 +/- 14 ms before taurine treatment to 137 +/- 12 ms after taurine (p less than 0.001), and the quotient pre-ejection period/left ventricular ejection time decreased from 47 +/- 9 to 42 +/- 8% (p less than 0.001). Side effects did not occur in the patients during taurine. The results indicate that addition of taurine to conventional therapy is safe and effective for the treatment of patients with congestive heart failure.

[Ruptured persistent primitive hypoglossal artery aneurysm: case report].

Persistent primitive hypoglossal artery is less common than persistent primitive trigeminal artery. About one hundred examples of such hypoglossal arteries have been demonstrated by angiography. The origin of persistent primitive hypoglossal artery is the cervical segment of the internal carotid artery, usually at the level of the first to second cervical vertebrae. The artery then enters, with varying degrees of tortuosity, the anterior condyloid (hypoglossal) canal and joints the basilar artery immediately above its lower end. When enlargement of this canal is identified, the presence of a persistent primitive hypoglossal artery should be strongly suspected. The homolateral vertebral artery is frequently hypoplasia. A 66-year-old man was brought to our hospital due to faintness. CT showed thick subarachnoid hemorrhage. Angiography showed that a persistent primitive hypoglossal artery aneurysm was present, but the posterior communicating artery was absent. Right vertebral angiography showed extravasation due to re-rupture of the aneurysm. An operation was performed at day 0 using the left transcondylar approach despite deterioration of SAH grading. Intraoperative re-rupturing occurred and the lower cranial nerves clustered around the aneurysm, so the aneurysm was partially clipped on the dome. The second angiography was carried out at day 10, and there was no vasospasm. Palsy of the lower cranial nerves appeared transiently. A ventricle-peritoneum shunt was required due to normal pressure hydrocephalus, but the patient was discharged with no neurological deficits.

[A case of Jefferson fracture treated with the Sof'wire cable system method of fixation].

Jefferson fracture is a very rare disease which occurs in only 2-13% of all cervical spinal fracture cases and in only 1.3% of total spinal fracture cases. A combination of an atlas-axis fracture occurs relatively frequently and with a higher incidence of neurological morbidity than isolated fractures. However, a Jefferson fracture, which is an isolated C-1 fracture, occurs very rarely. A 58-year-old woman was involved in a traffic accident and admitted to our hospital. She had a large scalp laceration in the parietal region and complained of nuchal pain. Neurological examination revealed nothing abnormal. A cervical x-p (lateral view) revealed no abnormal findings, but an open-mouth view revealed an 8 mm displacement (in total) in the lateral mass of the atlas. A cervical CT revealed a Jefferson fracture. Crutchfield traction was performed for 9 days followed by external immobilization with a halo-vest to allow the patient to be ambulatory quickly. A posterior occipitocervical fusion was performed with an iliac bone autograft using the Sof'wire Cable system for late cervical stability and reducing the period of rigid external immobilization. The postoperative state was uneventful. The halo-vest was removed 10 weeks after surgery. An x-p obtained 3 months postoperatively showed good stability of the cervical spine. The Sof'wire Cable system proved to be very useful.

[Case report: a foreign body (gauze) in the bladder].

A case of bladder tamponade caused by a foreign body (gauze) in the bladder of a 24-year-old man is reported. He had been treated with the Lambotte wire and screw to repair his pubic bone fracture caused by a traffic accident. About one year later, the wire and screw were removed from the patient. However, he suffered from gross hematuria and bladder tamponade on the 11th day after the 2nd operation, and he was transferred to our outpatient department on emergency. Further urological examinations were done for this case. The patient was diagnosed as having bladder tamponade caused by a foreign body, a gauze, in the bladder. Among these examinations NMR-CT gave us the most interesting and useful findings. NMR-CT showed that the gauze penetrated the bladder wall.

[Loco-regional cancer therapy for hepatic metastasis].

UNLABELLED: We undertook a clinical evaluation of chemotherapy for hepatic metastasis of gastric, colorectal and breast cancer. Between 1980 and 1989, chemotherapy for hepatic metastasis of gastric cancer was performed in 96 cases. Between 1973 and 1989, chemotherapy for hepatic metastasis of colorectal cancer and breast cancer was performed in 40 and 14 cases. RESULTS: (1) In hepatic metastasis of gastric cancer, the 50% survival period was 149 days in local injection therapy, 132 days in arterial infusion therapy and 117 days with no chemotherapy. There was no significant difference in the survival period in gastric cancer. (2) In hepatic metastasis of colorectal cancer, the 50% survival period was 445 days in arterial infusion therapy, 206 days in local injection therapy and 96 days with no chemotherapy. The survival period with hepatic metastasis of colorectal cancer that had undergone chemotherapy was longer than for no chemotherapy. (3) In hepatic metastasis of breast cancer, arterial infusion therapy was more effective, and the survival period was prolonged significantly.