Comparison of in vivo efficacy of hypoxic cytotoxin tirapazamine and hypoxic cell radiosensitizer KU-2285 in combination with single and fractionated irradiation

Development of strategies to eradicate radioresistant hypoxic cells would be of great benefit for clinical radiotherapy. In the present study, the in vivo effects of a promising hypoxic cytotoxin, tirapazamine (3-amino-1,2,4-benzotriazine 1,4-di-N-oxide), were examined in comparison with those of KU-2285, one of the best hypoxic cell radiosensitizers, in combination with both single and fractionated irradiation. The tumor response was assessed by the standard in vivo-in vitro clonogenic assay using SCCVII tumors in C3H mice and EMT-6/KU tumors in Balb/c mice with different characteristics of tumor hypoxia. With single-dose irradiation (18 Gy), both tirapazamine and KU-2285 showed significant enhancement of cell killing in a dose-dependent manner, but tirapazamine was more effective for SCCVII tumors with acutely hypoxic cells, while KU-2285 was more effective for EMT-6/KU tumors predominantly with chronically hypoxic cells. In fractionated irradiation regimens (4 fractions of 5 Gy at 12 h intervals), tirapazamine showed more marked combined effects at 10 and 20 mg/kg than KU2285 at 100-200 mg/kg in both SCCVII and EMT-6/KU tumors. We concluded that the effectiveness of KU-2285 and tirapazamine was correlated with the nature of tumor hypoxia with single-dose irradiation, whereas tirapazamine appeared more potent than KU-2285 with fractionated irradiation. These findings suggest the potential usefulness of tirapazamine in clinical fractionated radiotherapy.

Pravastatin prevents the progression of accelerated coronary artery disease after heart transplantation in a rabbit model

This study was designed to investigate the effects of pravastatin (Pr) on accelerated coronary arteriosclerosis in transplanted hearts. The rabbit hearts were transplanted to the recipients' neck heterotopically, and received FK506. The rabbits in group 1 were fed a normal diet (ND), and cholesterol-rich diet (CD) in group 2 and 3. Pr (10 mg/kg) was given to group 3. They were sacrificed at 4 weeks and the severity of myocardial rejection and arterio-sclerosis was assessed and scored histologically. The serum lipid levels were significantly elevated by a CD. However, addition of Pr had no effect on the levels of LDL and total cholesterol (TC). There was no significant difference in myocardial rejection in each group. Transplanted hearts in group 2 showed more severe arteriosclerotic lesions than those in group 1. Pr treatment in group 3 diminished the severity of coronary arteriosclerosis. Pr may prevent the accelerated coronary arteriosclerosis after heart transplantation without significant changes in TC and LDL.

Acute and subacute inhalation toxicity of dichlorosilane in male ICR mice

Using male ICR mice, the LC50 and acute and subacute inhalation toxicity of dichlorosilane (SiH2Cl2, DCS) and the fate of DCS released into the air were investigated. DCS resolved and minute particles including silicon and chloride were observed, when DCS was released into the air. Most particles were under 1 micron in diameter. The LC50 of DCS at 4-h exposure was 144 ppm (nominal concentration). In the acute inhalation study, ten mice in each group were exposed to 64 ppm (nominal concentration) DCS for 1, 2, 4 or 8 h. Body weight loss, wheezing and piloerection were observed in mice exposed for 2 h or more. Histopathologically, injury to the nasal mucosa and trachea were observed in all exposed mice. Mice exposed to 32 ppm (nominal concentration) DCS for 2 or 4 weeks also exhibited depression of body weight gain, wheezing and piloerection. Squamous metaplasia of the nasal mucosa and tracheal epithelium was observed in both 2- and 4-week exposure groups. Exposure to DCS was irritant or corrosive to the respiratory tract with both acute and subacute inhalation. Apart from silane (SiH4), toxic effects of DCS seem to be characterized by chloride compounds derived from DCS.

Identification of the coding region of Saccharomyces cerevisiae chromosome VI using the computer program GenMark

We searched the nucleotide sequence of budding yeast Saccharomyces cerevisiae chromosome VI (270 kb) for candidate coding regions, using the computer program GenMark. One hundred and twenty-nine putative genes were identified, which is almost the same as the number of ORFs on this chromosome. Nineteen new putative genes were identified through the GenMark analysis. Most large ORFs were also correctly identified (87% of the predicted putative genes identified by the GenMark (110 of 127) matched the reported ORFs). The new coding regions were mostly small but they were distinguished from the more than 2000 ORFs identified by Genetyx. GenMark did not predict 17 ORFs that were over 300 bp long. As these ORFs include known genes, their sequence context may differ somewhat from that of typical yeast genes. These analyses revealed the high potential of GenMark to identify putative genes from numerous short ORFs and will produce information on the likelihood of their being actual genes.

Cloning and sequencing of the chaperonin-encoding Cctd gene from Fugu rubripes rubripes

CCT, a chaperonin containing t-complex polypeptide 1 (TCP-1), is a cytosolic molecular chaperone involved in the folding of proteins. We have isolated the Cctd gene from a Fugu rubripes rubripes (Frr) genomic library using a rat Ccta cDNA as a probe, and cloned its cDNA by reverse transcription-polymerase chain reaction (RT-PCR) using a pair of oligodeoxyribonucleotides corresponding to the 5' and 3' non-coding regions of Frr Cctd. Cctd spans a region of 4.7 kb and consists of at least 13 exons with small introns of about 144 bp on average. The Cctd cDNA sequence revealed a deduced polypeptide of 536 amino acids sharing a high degree of homology with that of the mouse Cctd cDNA (88%). Cctd is present as a single-copy gene, as shown by genomic Southern blot analysis, and can be used for evolutionary and classification analyses of Fugu species.

[A case of Behçet's disease associated with aortic regurgitation and nephrotic syndrome]

A 50-year-old housewife with a main complaint of dyspnea was admitted to our hospital in September, 1992. In 1975, the patient developed aphthous stomatitis, genital aphthous ulcers, uveitis and erythema nodosum appeared and diagnosed as having Behcet's disease at Department of Dermatology of our hospital. Aortic regurgitation was pointed out in 1984. Hyperlipidemia appeared in January and Oral prednisolone was started in May, 1985. From April in 1987, proteinuria appeared. From January, 1988, urinal protein was greater than 300 mg/dl. Orthopnea appeared in July, 1992. Physical examinations revealed systolic and diastolic murmur and pretibial edema. Laboratory findings showed proteinuria (3.8 g/day) and hypoproteinemia (serum total protein 5.1 g/dl, serum albumin 3.1 g/dl). Microscopic findings of renal biopsy revealed mesangial proliferative glomerulonephritis and arteriosclerosis. Immunofluorescent studies demonstrated deposits of Apo B in the basement membrane and the mesangium. She was discharged from our hospital as proteinuria was decreased after a combination treatment with camostat mesilate 600 mg and SAIREITO 9.0 g. This patient developed nephrotic syndrome, which was caused by hypertension and hyperlipidemia in addition to Behcet's disease. This case is noteworthy because Behcet's disease is rarely complicated with nephrotic syndrome.

Sequencing of an 18.8 kb fragment from Saccharomyces cerevisiae chromosome VI

The nucleotide sequence of lambda phage clone 4121, which contains the 18.8 kb fragment of Saccharomyces cerevisiae chromosome VI left arm, was determined. This sequence had seven open reading frames (ORFs), four of which were identical to known genes (ACT1, YPT1, TUB2 and RPO41). Another three ORFs (4121orfR003, 4121orfR004 and 4121orfRN001) were highly homologous to FET3 multi-copper oxidase, glucose transport protein, and hypothetical protein of YIL106w on chromosome IX, respectively. 4121orfRN01 is suggested to contain an intron.

Clinical evaluation of the efficacy of EDTA solution as an endodontic irrigant

The effect of eliminating the smear layer by means of 15% EDTA solution as a root canal irrigant was studied in 189 single-rooted infected teeth. Each tooth was treated at two appointments, and the root canal bacteriological examination was studied on the first (pretreatment, and after enlargement and irrigation) and second (pretreatment) visits. The root canals were irrigated with 15% EDTA solution with ultrasonics agitation. No antibacterial intracanal medications were used between the appointment. When 15% EDTA solution was used, no bacteria could be recovered from 93 of 129 root canals at the sampling stage on second visit. No bacteria were found in 21 of 60 root canals when saline solution was used as an irrigant. These results suggest that 15% EDTA solution is more effective than saline solution as a root canal irrigant.

Small cytoplasmic RNA (scRNA) gene from Clostridium perfringens can replace the gene for the Bacillus subtilis scRNA in both growth and sporulation

Small cytoplasmic RNA (scRNA) is a member of an evolutionarily conserved signal-recognition-particle-like RNA family. Using a DNA fragment of Bacillus subtilis scRNA gene as a probe, we cloned and characterized a Clostridium perfringens gene encoding the scRNA. Mapping the 5' and 3' ends of scRNA revealed that C. perfringens scRNA consists of 269 nucleotides: the sequence has about 70% primary sequence homology with B. subtilis scRNA. The predicted secondary structure appeared to be similar to that of B. subtilis scRNA, indicating that there are domains I and II in C. perfringens scRNA, in addition to domain IV. Functional analysis showed that C. perfringens scRNA could compensate for vegetative growth and allow the formation of heat-resistant spores in an scRNA-depleted B. subtilis strain, whereas Escherichia coli 4.5S RNA could not maintain sporulation. Since both E. coli 4.5S RNA and C. perfringens scRNA have the same binding specificity to B. subtilis Ffh protein, the difference in complementation activity reflects the function of domains I and II.

[A case of severe sarin poisoning in the sarin attack in Matsumoto--one-year follow-up of clinical findings, and laboratory data]

A patient severely poisoned with sarin in the Sarin Attack in Matsumoto is described. A 19-year-old man was exposed to sarin at 23:00 on 27 June, 1994. At 1:00 of the following day, a rescue team found and brought him to the hospital. His blood pressure was 150-80mmHg and the heart rate was 120/min with frequent premature ventricular contractions (PVC). His respiration was shallow and copious salivation and excretion from the respiratory tract were observed. Consciousness disturbance, generalized convulsion, severe miosis and fasciculation of tongue, facial muscle and extremities were also marked. Serum cholinesterase was 21 U/l (normal 109-249) and acetylcholinesterase in erythrocyte (E-AchE) was 0.1U/l (normal 1.2-2.0). Electroencephalogram (EEG) 30 hours after exposure showed polispike and wave complexes. Ventilatory assistance, forced urination and injection of diazepam and atropin improved his general condition and he was discharged 18 days after exposure. Three months after exposure, E-AchE was normalized and there was no complaint. But one year after exposure, EEG showed epilecpic discharges during sleep, and Holter electrocardiogram showed frequent PVC. As no clinical cases of severe sarin poisoning like this patient was reported, a longterm follow-up of this patient is very important.

Inhibition of aldosterone turn-off phenomenon following chronic adrenocorticotropin treatment with in vivo administration of antiglucocorticoid and antioxidants in rats

Chronic adrenocorticotropin (ACTH) treatment in rats leads to a fall in aldosterone secretion (aldosterone turn-off or "aldosterone escape" phenomenon) with a concomitant rise in corticosterone. To elucidate whether ACTH-induced aldosterone suppression is mediated by steroid type II receptor or related to a free-radical effect by over-synthesized corticosterone, we examined the effects of a glucocorticoid antagonist, RU486, and antioxidants dimethyl sulfoxide (DMSO) and vitamin E, on the aldosterone turn-off phenomenon in rats. Each rat received daily for 5 days a different dose of ACTH-Z (5, 10, 20 or 40 micrograms/100 g body weight) 1 mg RU486/100 g body weight, 100 microliters (1.3 mmol) DMSO/100 g body weight or 2 mg vitamin E/100 g body weight with subcutaneous injection. Plasma steroid levels and in vitro release of steroids from the adrenal capsule were measured. The ACTH-Z treatment caused a dose-dependent increase in corticosterone and a decrease in aldosterone in both plasma and adrenal capsule experiments, as well as an increase in adrenal weights. For the following study 5 micrograms/100 g body weight of ACTH-Z was used. Administration of RU486 alone caused no change in plasma aldosterone level compared to controls, even though the steroid type II receptor was blocked, as evidenced by significant increases in plasma ACTH and corticosterone levels. Concomitant administration of RU486 and ACTH-Z increased both plasma corticosterone and aldosterone levels (p < 0.01) but decreased adrenal capsule corticosterone production (p < 0.05) compared to the rats treated with ACTH-Z alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Prolonged repolarization during hypoxemia in epicardial electrogram: difference from ischemia and a competitive action of cyclic AMP

The effects of regional hypoxemia and ischemia on epicardial electrogram were studied in anesthetized, open-chest dogs. The left circumflex artery (LCx) was cannulated and perfused with either arterial blood or hypoxic solution. A contact electrode for recording monophasic action potential (MAP) was applied to the epicardial site of the LCx area. Epicardial electrograms and MAP in the LCx perfusion territory were recorded 1) just before and at the end of a 2-min coronary occlusion (ischemia) and 2) just before and at the end of a 2-min perfusion of hypoxic solution (hypoxemia). The activation-recovery interval (ARI), defined as an interval from the minimum derivative of the QRS complex to the maximum derivative of the T-wave in the unipolar electrogram, changed linearly with MAP duration during above interventions. The ARI decreased by 29% from 189 +/- 14 to 134 +/- 30 ms during ischemia (p < .001), and it increased by 39% from 183 +/- 11 to 254 +/- 31 ms during hypoxemia (p < .001). Hypoxemia produced a giant negative T-wave whose pattern was not modified by pretreatments with autonomic nerve blockers (propranolol and atropine), a Ca2+ channel blocker (verapamil), an ATP-sensitive K+ channel (KATP blocker (5-hydroxydecanoate or transient outward K+ current (I(to) blocker (4-aminopyridine). Isoproterenol, forskolin or aminophylline inhibited both the appearances of giant negative T and the ARI prolongation. Accordingly, unlike ischemia, hypoxemia prolongs repolarization process and this prolongation is inhibited by the augmentation of intracellular cyclic AMP.

Atlanto-occipital hypermobility in subjects with Down's syndrome

STUDY DESIGN

The upper cervical spines of 57 subjects with Down's syndrome were retrospectively examined, with special attention to atlanto-occipital mobility.

OBJECTIVE

To examine the magnitude of atlanto-occipital mobility and its clinical significance in subjects with Down's syndrome.

SUMMARY OF BACKGROUND DATA

Atlanto-occipital translation of more than 1 mm in adults implies instability. However, the normal value in children with Down's syndrome has not been established, and the value in Down's syndrome has not been evaluated based on a comparison between subjects with Down's syndrome and control subjects.

METHODS

Measurements were made by Wiesel and Rothman's method in 38 subjects with Down's syndrome and 34 control subjects.

RESULTS

Atlanto-occipital translation in the Down's syndrome group ranged from 0-6.4 mm (mean, 2.3 mm), whereas in the control group it ranged from 0-2.1 mm (mean, 0.61 mm). The difference was statistically significant. Of the 38 subjects with Down's syndrome, 37 were asymptomatic.

CONCLUSION

The magnitude of atlanto-occipital translation, as expected, apparently was greater in subjects with Down's syndrome than in control subjects. Although the possibility of neurologic complications should be considered whenever unusually high atlanto-occipital mobility is seen, a majority of the subjects with Down's syndrome were asymptomatic.

Capillaries with fenestrae in the rat soleus muscle after experimental limb immobilization

Capillaries in the rat soleus muscle were examined by electron microscopy 4 weeks after limb immobilization and compared to those in untreated muscle. Immobilized muscles showed degenerative changes such as dissolution of sarcomeres, vacuoles, and a small increase in connective tissues, including collagen fibers, around muscle fibers. Eight percent of the capillaries in these muscles were found to have fenestrae. The non-nuclear portions of the endothelial cells were extremely thin and were perforated by several fenestrae which were bridged by a single-layered diaphragm. The untreated muscles contained only continuous capillaries. These findings suggest that the occurrence of capillaries with fenestrae in the immobilized muscle may be a result of structural changes in the muscle.

Transient increase of cyclic AMP induced by glutamate in cultured neurons from rat spinal cord

We demonstrated that glutamate increased the cyclic AMP level in cultured neurons from rat spinal cord. A bath application of glutamate (300 microM) elicited a rapid increase of the cyclic AMP concentration reaching a level three times as high as the basal level in approximately 3 min, and its content then decreased to the control level in 15 min. The increase was not observed in a Ca(2+)-free medium and was inhibited by an antagonist of NMDA receptors or a voltage-sensitive Ca2+ channel blocker. Preincubation with W7 also inhibited the glutamate-evoked cyclic AMP increase. NMDA, aspartate, and high-K+ conditions also induced a cyclic AMP increase; however, a decreasing phase did not follow. The decreasing phase was observed when (2S,1'S,2'S)-2-(carboxycyclopropyl)-glycine, a potent agonist for metabotropic glutamate receptors, was combined with NMDA. These results suggest that the cyclic AMP increase is mediated by a Ca2+ influx via both NMDA receptors and voltage-sensitive Ca2+ channels followed by an activation of the Ca2+/calmodulin system, and the decreasing phase observed in the case of glutamate exposure is due to the activation of the metabotropic glutamate receptors.

[Surgical repair of ventricular septal perforation following acute myocardial infarction in an 86-year-old man]

We reported on an 86-year-old man who underwent successful repair of ventricular septal perforation (VSP). He was admitted to our hospital with acute inferior myocardial infarction (MI). Color Doppler echocardiogram showed the VSP located in posterior ventricular septum and right heart catheterization revealed a Qp/Qs of 2.1. His hemodynamic condition worsened, necessitating initiation of intraaortic balloon pumping 11 days after the onset of MI. Surgical repair of the VSP was performed on that day. A posterior ventricular septal defect was repaired using the method advocated by Daggett: the ventricular septal defect was closed with a Teflon felt patch, and left ventricular free wall was closed with an artificial graft. The postoperative course was uneventful, and the patient is doing well at one year after operation. He was, to the best of our knowledge, the eldest patient to undergo successful operation for VSP in Japan.

GAPO syndrome: report on the first case in Japan

We studied a 3.5-year-old Japanese boy with growth retardation, alopecia, pseudoanodontia, and bilateral papilledema. He was born of nonconsanguineous parents, but his paternal grandparents were related. From his characteristic physical manifestations, we diagnosed him as the first known case of GAPO syndrome in Japan and perhaps in the Mongoloid race. Our case had prominent dilatation of scalp veins and an audible intracranial bruit. Cranial angiography documented a narrowing of the sigmoid sinuses, with no flow to either jugular vein. We discuss here the relationships between optic atrophy and intracranial vascular changes in this syndrome.

[Efficacy of simultaneous function and perfusion imaging on 99mTc-tetrofosmin myocardial scintigraphy]

The aim of this study was to determine whether the diagnosis for coronary artery disease (CAD) with 99mTc-tetrofosmin (Tf) myocardial scintigraphy was improved by the combination of function image and perfusion image as compared with perfusion alone. Tf myocardial scintigraphy was performed with one-day protocol (stress/rest) in 51 patients (CAD: 32, Non-CAD: 19) without previous myocardial infarction. Function image was obtained by first pass method, and perfusion image by SPECT. Number of diseased vessels was 14 in right coronary artery (RCA), 18 in left anterior descending (LAD), and 12 in left circumflex (LCX). Ischemia was diagnosed by 2 different parameters 1) perfusion image alone, 2) combination of perfusion image and regional ejection fraction (rEF). On perfusion image, accuracy was 53%, 94% and 86% in RCA, LAD, and LCX respectively. On perfusion + rEF, accuracy was 76%, 90% and 84% in RCA, LAD, and LCX respectively. Specificity in RCA was 45% on perfusion, 84% on perfusion + rEF. Sensitivity in RCA was 77% on perfusion, 54% on perfusion + rEF. LAD and LCX did not change by the addition of function image. By addition of function image, accuracy and specificity of diagnosis in area of RCA improved significantly (p < 0.01). Thus the addition of function image in Tf myocardial scintigraphy would be useful to improve the diagnosis, especially in region of RCA.

Neurotoxicity of acromelic acid in cultured neurons from rat spinal cord

Acromelic acid A, which contains the kainic acid structure in its molecule, is known to cause selective damage of interneurons in the rat lower spinal cord. In the present study, the potent neurotoxicity of acromelic acid A was demonstrated in cultured rat spinal neurons in terms of the activity of lactate dehydrogenase that was released from degenerated neurons into the culture medium. Acromelic acid A increased the lactate dehydrogenase activity in time- and concentration-dependent manners, and its EC50 was about 2.5 microM, which was much lower than that of kainic acid (70 microM) and (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (EC50; 11 microM). The maximum level of lactate dehydrogenase released by acromelic acid A was quite similar to that by kainic acid, but was about twice the level produced by (RS)-alpha-3-hydroxy-5-methyl-4-isoxazolepropionic acid. Exposure to acromelic acid A caused release of L-glutamate from the cells into the medium; however, the concentration of L-glutamate released was far below the level for inducing the neurotoxic effects. The neurotoxicity of 10 microM acromelic acid A was almost completely inhibited by 30 microM 6-nitro-7-sulphamoylbenzo(F)quinoxaline-2,3-dione and 6-cyano-7-nitroquinoxaline-2,3-dione, potent antagonists for non-N-methyl-D-aspartate receptors, but was partly (35%) reduced by 30 microM dizocilpine maleate. In cultured hippocampal neurons, the toxicity of acromelic acid A was significantly less effective (EC50: 18 microM) than that in spinal neurons, whereas the toxicity of kainic acid was almost the same in both neurons. These results suggest that acromelic acid A directly activates non-N-methyl-D-aspartate receptors on the cultured spinal neurons to induce neuronal death. A new type of non-N-methyl-D-aspartate receptors which is specific to acromelic acid A is suggested to be present at least in spinal neurons.

Pharmacokinetics of wood creosote: glucuronic acid and sulfate conjugation of phenolic compounds

Wood creosote, principally a mixture of non-, alkyl- and/or alkoxy-substituted phenolic compounds, was orally administered to adult male volunteers to determine its metabolites and pharmacokinetic parameters. After a 133-mg single dose, its major constituents (i.e. phenol 15 mg, guaiacol 32 mg, p-cresol 18 mg and creosol 24 mg) were found in peripheral venous blood and urine, mostly as glucuronic acid and, except for creosol, as sulfate conjugates. Low concentrations of unconjugated phenols were also detected. The metabolites in the serum started to increase 15 min after the dose, and they reached their maximum concentrations 30 min after administration. The maximum concentrations of glucuronides were 0.18 +/- 0.07, 0.91 +/- 0.38, 0.33 +/- 0.18 and 0.47 +/- 0.23 mg/l; those of sulfates were 0.16 +/- 0.06, 0.22 +/- 0.09, 0.17 +/- 0.07 and < 0.04 mg/l for phenol, guaiacol, p-cresol and creosol, respectively. The 24-hour urinary recoveries of the sum of each compound and its metabolites were 75 +/- 35, 45 +/- 36, 103 +/- 51 and 74 +/- 36%, in the above order. The presence of guaiacol glucuronide in blood and urine was directly verified by its isolation and structure analyses.

[Study on therapeutics adopted after occlusion of intraarterial reservoir in patients with liver tumor]

Over the last 5 years, we experienced thirty-nine patients with liver tumors undergoing implantation of an intraarterial reservoir through the gastroduodenal artery. Nine of the 39 patients had hepatocellular carcinomas, while the rest had metastatic liver tumors. In 32 patients, intraarterial chemotherapy via an implanted reservoir was discontinued either because of death in 20 patients with an average survival period of 11.7 months or because of occlusion of an intraarterial line in 12 patients with an average treatment period of 20.2 months. Regarding treatment modalities adopted for intraarterial therapy, transcatheter arterial embolization, surgical resection, microwave tumor coagulation, ethanol injection therapy, and a subselective intraarterial chemotherapy were performed in 3 patients with hepatocellular carcinomas. All of them survived more than 2 years after disuse of the reservoir. Out of 5 patients with metastatic liver tumors of colorectal cancer, one patient underwent additional surgical resection, two patients had no therapy who survived only two or three months, and two patients were still alive without additional therapies. Of four patients with metastatic liver tumors, 3 from breast cancer and one from leiomyosarcoma of stomach were treated with systemic chemotherapy or subselective intraarterial chemotherapy combined with radiation therapy. The average survival period of these 12 patients was 16.2 months, and 7 of them are still alive.