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Biomedical subjects

T Horiguchi

Publications and source records attributed to T Horiguchi.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Operation for left renal cell carcinoma complicated with acute pulmonary tumor embolism and cocurrent removal of tumor].

The prognosis of pulmonary tumor embolism is said to be poor and only a limited number of patients with this disease have survived. The patient was a 64-year-old male suffering from left renal cell carcinoma complicated with tumor extending from the left renal vein to the inferior vena cava. The patient underwent an operation for left renal cell carcinoma during which he developed tumor embolus to the pulmonary artery. The occurrence of the acute embolism was promptly detected and the removal of tumor was performed under cardiopulmonary bypass. The patient made good postoperative progress.

Acute Disease↗
PubMed1997

The quaternary geometry of transcription termination factor rho: assignment by chemical cross-linking.

Transcription termination factor rho from Escherichia coli is a ring-shaped homohexamer of 419 amino acid subunits and catalyzes an ATP-dependent release of nascent RNA transcripts. Previous chemical cross-linking studies suggested that the rho hexamer might have D3 symmetry with three isologous dimers as protomers. However, our recent mutational analysis of rho alongside its putative structural homology to F1-ATPase rather argued for C6 symmetry. To resolve this discrepancy, we have re-investigated the pattern of cross-linking of rho using various cross-linkers with different functional groups and spacer lengths. Upon reaction with dimethyl suberimidate followed by SDS-polyacrylamide gel electrophoresis, rho protein generated a series of cross-linked oligomers up to hexamers, of which dimers migrated as distinct doublet bands of approximately equal intensities. However, the lower band became much stronger than the upper one with dimethyl adipimidate and difluorodinitrobenzene, and vice versa with disuccinimidyl glutarate, disuccinimidyl suberate and disulfosuccinimidyl tartarate. Furthermore, the trimeric products also produced doublet bands, whose relative intensities were again variable with cross-linkers, but in an inverse correlation with those of the dimer bands. These results combined with theoretical considerations support a C6 symmetry model in which cross-linking is assumed to occur stochastically at one of two alternative sites within each subunit interface with variable relative frequencies depending on cross-linkers. The D3 symmetry is excluded, for the putative trimeric subspecies should always retain mutually equal intensities in that case. Detailed inspections of the cross-linking kinetics further revealed a moderate characteristic of C3 symmetry for the rho hexamer such that the collective as well as relative rates of cross-linking at the two available sites could fluctuate between alternating interfaces. The final model designated as C3/6 is also compatible with other functional and structural properties known for rho.

Cross-Linking Reagents↗
PubMed1997

Effects of triphenyltin chloride and five other organotin compounds on the development of imposex in the rock shell, Thais clavigera.

The imposex promotion activities of six organotin compounds--tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT), triphenyltin (TPT), diphenyltin (DPT) and monophenyltin (MPT)--were examined by injection experiments with the rock shell, Thais clavigera (Prosobranchia; Muricidae). TPT and TBT had strong effects on the development of imposex in the rock shell (p<0.001). The other organotin compounds (DBT, MBT, DPT and MPT) had no or less effects on the development of imposex in T. clavigera. The difference between the effects of TPT and TBT was statistically insignificant (p>0.01). The effects of these compounds are estimated, from the relationships between TBT or TPT concentration in tissue and mean penis length of females after injections, to be approximately the same.

Journal Article↗
PubMed1997

[A case of dyskeratosis congenita with acute interstitial pneumonia].

This is a rare case of Dyskeratosis Congenita (DC) with acute interstitial pneumonia. A 51-year-old man with DC was admitted to our hospital because of cough, sputum and fever. Chest X-ray film showed ground glass opacities in all lung fields for a while steroid's therapy proved effective, but about seven months later the patient's condition became serious. Methylprednisolone, cyclophosphamide and mechanical ventilation therapy were not effective. He died and an autopsy was performed. The lung specimen showed Organizing Diffuse Alveolar Damage, and some parts pointed to bacterial infection. But Pneumocystic carinii pneumonia and Fungal infections were not found. It is therefore necessary to conduct intensive examinations of lung involvement of patients with Dyskeratosis Congenita.

Acute Disease↗
PubMed1996

Formation of apatite-collagen complexes.

An apatite-collagen complex was prepared in calcium beta-glycerophosphate solutions at pH 9.0 and 37 degrees C with the purpose of developing new bone substitutes that more closely resemble bone than currently available materials. Reconstituted type I collagen as well as sheet collagen were crosslinked in the presence of alkaline phosphatase and egg-yolk phosvitin. The crosslinked collagens were immersed in daily-renewed calcium beta-glycerophosphate solutions for 2 and 4 weeks to induce the deposition of apatite on the collagen fibers. After 2 weeks of reaction, for example, apatites deposited approximately two times the crosslinked collagen in weight. With reconstituted collagen, the complex showed some elasticity but no apatite was visually observed to detach under deformation with fingers and forceps. The complex, moreover, did not disintegrate when immersed in saline or animal blood. Nevertheless, the complex resorbed with no evidence of cytotoxicity when implanted in muscle tissues. These findings suggest that the apatite-collagen complex prepared would be useful as bone substitutes, especially for periodontal osseous lesion repair and alveolar ridge augmentation.

Alkaline Phosphatase↗
PubMed1996

Dibutyryl cAMP improves systemic vasoconstriction caused by endotoxin in dogs.

We studied whether dibutyryl cyclic adenosine monophosphate (DbcAMP), which freely penetrates into the cells, improves systemic vasoconstriction caused by endotoxin in dogs. Thirteen anesthetized dogs were randomized into three groups. The endotoxin (ETX) group (n = 5) received only Escherichia coli endotoxin (3 mg.kg-1, intravenously). The ETX + DbcAMP group (n =5) received DbcAMP (6 mg.kg-1, intravenously) 30 min before the administration of endotoxin. The DbcAMP group received the same dose of DbcAMP 30 min after administration of saline. In the ETX group, systemic blood pressure and cardiac index significantly decreased, and systemic vascular resistance significantly increased, while in the ETX + DbcAMP group, increases in systemic and pulmonary vascular resistances after the administration of endotoxin were attenuated. DbcAMP did not cause hemodynamic changes in normal dogs. Plasma concentrations in thromboxane B2 in the ETX group were higher than in the ETX + DbcAMP group. Also, the change in plasma cyclic AMP concentrations showed a good logarithmic correlation with the change in plasma thromboxane B2 concentrations after the administration of endotoxin (r = .908, log (delta T x B2) = -.002* (delta cAMP) + 3.786). We conclude that DbcAMP improves systemic vasoconstriction caused by endotoxin in dogs. The beneficial mechanism of DbcAMP on systemic vasoconstriction after the administration of endotoxin may be partially due to inhibition of thromboxane B2.

Animals↗
PubMed1996

Pulmonary responses to heparin-protamine complexes: the effects of age and species.

To test the hypothesis that heparin-protamine complexes (H-P complexes) react with pulmonary intravascular macrophages, we studied the difference in the pulmonary reaction to H-P complexes between goats and rabbits and among different-aged goats. The increases in pulmonary arterial pressure (Ppa) and plasma thromboxane levels (Tx) after injection of H-P complexes (1.2 ml/kg) in goats (delta Ppa = 17 +/- 7.0 mmHg, delta Tx = 17.3 +/- 10.1 ng/ml) were significantly greater than in rabbits (delta Ppa = 0.50 +/- 1.0 mmHg, delta Tx = -0.01 +/- 0.17 ng/ml), the increase in Ppa in adult goats (> 150 days old; delta Ppa = 17 +/- 7.0 mmHg) was about sixfold higher than in newborn goats (1-3 days old; delta Ppa = 2.8 +/- 4.0 mmHg), and the increase in Tx in adult goats (delta Tx = 17.3 +/- 10.1 ng/ml) was significantly greater than those in newborn and young (19 days old) goats (delta Tx = 0.69 +/- 0.48 and 3.60 +/- 0.36 ng/ml, respectively). The pulmonary hemodynamic reaction to H-P complexes is consistent with the concept that the H-P complexes react with pulmonary intravascular macrophages.

Aging↗
PubMed1996

[Middle lobe syndrome--incidence and relationship to atypical mycobacterial pulmonary disease].

We evaluated the incidence of middle lobe syndrome in the Haibara area, and its relationship to atypical mycobacterial infection. Of the 30,588 persons who underwent annual mini-chest roentgenography in 1992 or 1993 or both, 51 (0.17%) had middle lobe syndrome, diagnosed from posteroanterior and lateral chest X-ray films. The incidence was significantly higher in persons over 50 years old than in persons under 50 years old (0.26% vs 0.02%: p < 0.001), and was higher in femals than in males (0.20% vs 0.11%: p = 0.527). Of 16 patients examined by bronchoscopy and computed tomography, 7 showed evidence of cylindrical bronchiectasis, and four had mycobacterium avium complex pulmonary disease presenting as middle lobe syndrome. All four were women who were 51 years of age or older and none had predisposing pulmonary disorders. Computed tomography showed multiple nodular shadows with or without bronchiectasis located in the middle lobe or the lingula. Cavitary lesions were not seen. These results indicate that middle lobe syndrome is not rare, and that infection with mycobacterium avium complex should be considered when multiple nodular shadows are seen in the middle lobe or the lingula.

Adult↗
PubMed1996

[Swyer-James syndrome with unilateral pulmonary edema].

A 64-year-old man with ischemic heart disease was admitted to our hospital because of dyspnea. A chest X-ray film showed a butterfly shadow in the right lung. A chest X-ray film obtained before the patient had respiratory symptoms showed hyperlucency of the left lung. CT scans obtained at maximal inspiration and expiration revealed air trapping. Pulmonary arteriography showed that the left pulmonary artery and its branches were very small. Cardiac catheterization showed poor cardiac function. Swyer-James syndrome should be included in the differential diagnosis of patients with unilateral pulmonary edema.

Bronchial Diseases↗
PubMed1996

-A successful case of hypertrophic cranial pachymeningitis treated by optic nerve decompression.

A successful direct operation in a case of hypertrophic cranial pachymeningitis (HCP) is described. A 51-year-old male was admitted with right visual disturbance. CT scanning revealed a mass lesion in the right middle cranial fossa extending into the right orbita. From MRI it was ascertained that this mass lesion consisted of thickening of the skull base dura. The effect of steroids was transient and his visual disturbance was rapidly increasing. A direct operation was performed consisting of partial dissection of the thickening dura and decompression of the right optic nerve. Histological diagnosis showed HCP. After surgery his symptoms dramatically improved. The etiology, natural course and treatment of HCP are well reported in the literature. in the present case the etiology was not clear, but there was a possible relationship with intraorbital pseudotumor or multifocal fibrosclerosis. The reported occasional transitory effect of steroids on HCP and a poor prognosis for visual acuity are common traits in these patients. The authors thus feel that a direct operation should be immediately carried out when the effect of steroids on visual disturbances associated with HCP is judged transient.

Humans↗
PubMed1996

[Bronchiolitis obliterans preceding rheumatoid arthritis: effect of clarithromycin].

A 62-year-old man was referred to our department because of exertional dyspnea and a 6-year history of coughing and sputum production. He had never smoked, and had had an operation for chronic paranasal sinusitis. Coarse crackles and rhonchi were audible over both lower lung fields. The cold hemagglutinin titers were high. pulmonary function tests showed airflow obstruction, and a sputum culture revealed Hemophilus influenzae A chest X-ray film and a CT scan showed diffuse micronodular shadows in the centrilobular regions, mild ectasis of bronchioles mainly in the lower lung fields, and mild hyperinflation. A specimen of lung tissue was obtained by thoracoscopic biopsy, and histologic examination showed bronchiolitis obliterans, with bronchiolar narrowing or obliteration due to submucosal fibrosis and inflammation. Rheumatoid arthritis was diagnosed 14 months after the operation. The patient was treated with clarithromycin for 3 years. Respiratory symptoms were relieved and pulmonary function gradually improved.

Anti-Bacterial Agents↗
PubMed1996

[Fulminant interstitial pneumonia associated with polyarteritis nodosa].

A 54-year-old man was referred to our hospital because of fever, abdominal pain, hematemesis, and dyspnea on exertion. Laboratory examination on admission revealed elevations of WBC count and CRP. a low serum complement level, hypoxemia, and microhematuria. A chest X-ray film and a CT scan showed bilateral interstitial pneumonia and cardiomegaly. Angiography showed microaneurysms in peripheral branches of the superior mesenteric artery, the hepatic artery, and the right renal artery. Examination of a specimen of the right quadriceps muscle revealed arteritis with fibrinoid necrosis in a small artery, which was consistent with polyarteritis nodosa (PN). A specimen obtained by transbronchial lung biopsy before treatment showed interstitial mononuclear cell infiltration and edema. PN with interstitial pneumonia was diagnosed and the patient was treated with 1 g of methylprednisolone for 3 days, followed by 60 mg of prednisolone and 100 mg of cyclophosphamide daily. The interstitial pneumonia progressed. Despite a second trial of steroid pulse therapy in addition to mechanical ventilation and various kinds of antibiotics, the patient died of respiratory failure on the 35th hospital day. A specimen obtained by transbronchial lung biopsy 3 days before death revealed proliferation of fibroblasts, mononuclear cell infiltration in the interstitium, and hyaline membrane formation in air spaces. No evidence of infection was found. Interstitial pneumonia associated with PN had been considered to be quite rare, but recently some cases resembling the present case have been reported. We believe that interstitial pneumonia associated with PN might not be rare, and the present case shows that it can be fulminant.

Humans↗
PubMed1995

Structural and functional dissections of transcription termination factor rho by random mutagenesis.

Transcription termination factor rho from Escherichia coli is a homohexamer of 419 amino acid subunits and catalyzes an ATP-dependent release of nascent RNA transcripts. A rho monomer has three distinct domains functioning independently at the first approximation: the amino-terminal one quarter containing a primary RNA-binding site, the central 270-amino acids region constituting an ATP-binding domain with homologies to F1-ATPase, and the carboxy-terminal remainder with unknown function(s). To further delineate the structural and functional organizations of rho protein, we undertook its random mutagenesis using error-prone polymerase chain reactions with the carboxy-terminal 100-amino acid region chosen as the initial target. From 14 mutants identified, rho protein was purified and characterized in vitro. Of these, 11 mutants are defective in termination in vivo and show decreased activities in various partial functions examined: ATP binding; RNA binding; and ATPase activities dependent on three cofactors with decreasing efficacies, poly(C), lambda cro RNA and poly(U). A few of them are also affected in the putative secondary RNA-binding site that is functionally coupled to ATP hydrolysis. By contrast, the three other mutants are hyperactive in termination, poly(U)-dependent ATPase activity, and RNA interaction at the primary site. In these properties, the hyper-terminating mutants strikingly resemble the "super rho" mutant formerly found in the amino-terminal domain. Taken together, these findings indicate that the carboxy-terminal region plays a pivotal role in functionally coupling the RNA and ATP-binding domains, plausibly by acting as an interface for their interaction within or across individual subunits. In light of the reported X-ray crystallographic structure of F1-ATPase, we propose a model for the tertiary and quaternary structure of rho that is consistent with the observed mutational effects as well as a number of structural and functional properties characteristic of rho.

Adenosine Triphosphate↗
PubMed1995

Rescue of Schizosaccharomyces pombe from camptothecin-mediated death by a DNA topoisomerase I inhibitor, TAN-1518 A.

TAN-1518 A is a cytotoxic agent with suppressive activity against Meth A fibrosarcoma in vivo. This compound inhibits calf thymus DNA topoisomerase I (Topo I) but does not stimulate cleavable complex formation in the nuclei of Chinese hamster ovary (CHO)-K1 cells, suggesting that it inhibits Topo I in a manner different from that of camptothecin (CPT). To clarify the mode of action of TAN-1518 A, we examined its effects on the eukaryotic microorganism Schizosaccharomyces pombe (S. pombe), which does not require Topo I as an essential factor for growth. TAN-1518 A inhibited purified S. pombe Topo I as potently as did CPT. TAN-1518 A, unlike CPT, did not stimulate Topo I-induced DNA cleavage; instead, it inhibited CPT-induced cleavable complex formation. We constructed a S. pombe strain, IR9, that produced excess Topo I. IR9 was hypersensitive to CPT, but its growth was not affected by TAN-1518 A. The CPT-mediated death of IR9 cells was reduced dramatically in the presence of TAN-1518 A. These findings clearly demonstrate that TAN-1518 A is a specific inhibitor of Topo I in eukaryotic cells and also suggest that this agent inhibits some earlier step(s) that occurs before the formation of cleavable complex on DNA strands in the catalytic cycle of this enzyme.

Base Sequence↗
PubMed1995

Heparin-protamine complexes cause pulmonary hypertension in goats.

BACKGROUND: Protamine reversal of heparin-induced anticoagulation causes thromboxane release followed by pulmonary vasoconstriction in sheep and pigs. The aim of this study was to determine whether heparin-protamine (H-P) complexes are causative agents of thromboxane release followed by pulmonary hypertension associated with protamine reversal of heparin. METHODS: We separated H-P complexes and non-heparin-protamine (non-H-P) complexes from heparinized defibrinated human plasma neutralized with protamine by chromatography and studied the changes in hemodynamics, airway pressure, and thromboxane B2 concentration after injection of H-P complexes or non-H-P complexes into seven goats. In addition, we studied whether these pulmonary responses were blocked in goats pretreated with cyclooxgenase inhibitor (Indomethacin, n = 5) or thromboxane synthetase inhibitor (OKY-046, n = 5). RESULTS: A very small dose of H-P complexes increased pulmonary arterial and peak airway pressures and was followed by thromboxane B2 release (from 12 [5.5-23] to 28 [16-44] mmHg, from 9.0 [7.5-15] to 12 [8-19] cmH2O, and from 0.85 [0.34-3.2] to 16.4 [1.4-39.3] ng.ml-1, respectively). On the other hand, animals that received non-H-P complexes showed no significant changes. Indomethacin totally blocked and OKY-046 partially blocked the increases in pulmonary arterial pressure and thromboxane B2 concentration. CONCLUSIONS: H-P complexes play a major role in pulmonary hypertension after protamine reversal of heparin, and thromboxane A2 is a main mediator of the pulmonary hypertensive response to H-P complexes in goats.

Animals↗