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Biomedical subjects

H Sakai

Publications and source records attributed to H Sakai.

At least 523 records · Page 29Linked to original sources
PubMed1996

DNA replication of IncQ broad-host-range plasmids in gram-negative bacteria.

Bacterial plasmids of Escherichia coli incompatibility group Q (IncQ) are broad-host-range plasmids that are able to proliferate in almost all Gram-negative bacteria. They are small, nonconjugative, and multicopy plasmids. They can be mobilized into many species of Gram-negative bacteria by coresident conjugative plasmids. Plasmids RSF1010, R1162, and R300B have DNAs of a size of 8.7 kb, and are best studied among IncQ plasmids. These plasmids encode by themselves three major proteins essential for the initiation of DNA replication. This makes the plasmid DNA replication less dependent on the DNA replication apparatus of host cells, and leads to promiscuity or a broad host range. Considering the biological features of these plasmids, they are potent DNA cloning vehicles. Moreover, their characteristic DNA replication mechanism that makes IncQ plasmids promiscuous is elaborate, and is an interesting object of scientific studies.

DNA Replication↗
PubMed1996

Ameloblastoma with prominent ossification in the mandible of a dog.

A rare case of ameloblastoma with prominent stromal ossification in an 8-year-old female dog was studied. A bony mass recurred rapidly in the right mandible at the first molar region. Histopathologic examination revealed the lesion to be an atypical variant of ameloblastoma. Epithelial cells showed marked cell atypia, and mitotic figures were rather common. The collagenous stroma was abundant, with prominent formation of bone trabecular rimmed by active osteoblasts. The tumor was highly proliferative and aggressive, and thought to be malignant in nature.

Ameloblastoma↗
PubMed1996

Spontaneous vascular mineralization in the brain of horses.

Cerebral vascular mineralization was found in 12 (60%) of 20 3- to 10-year-old healthy horses collected at an abattoir. It was variable in degree and occurred mostly in the pallidal arteries showing two types of lesions; small globoid bodies along capillaries, and amorphous deposits in the wall of arterioles, small- or medium-sized arteries and veins. Both types were strongly positive for periodic acid-Schiff reaction, and weakly positive for von Kossa's and Berlin blue stains. Elemental analysis of the deposit revealed the presence of large amounts of aluminum, moderate amounts of phosphorus, zinc, calcium and iron, and a small amount of sodium.

Aging↗
PubMed1996

Echinococcus multilocularis coproantigen detection in golden hamster, an alternative definitive host.

Golden hamsters as alternative definitive hosts of Echinococcus multilocularis were used for coproantigen detection by means of sandwich ELISA. The test was performed in hamsters infected with approximately 20,000, 4,000, 500, 0 (control) and 100,000 (i.e., group I, II, III, IV and V respectively) protoscoleces. Comparison of mean OD values of each group showed significant differences depending on the number of protoscoleces administered and days postinfection. There was also a relatively high statistical correlation between the number of recovered worms and ELISA OD values (correlation coefficient = 0.699, P < 0.05), although accurate comparison of worm burdens among individual animals was difficult when numbers of infecting worms fell within the same range.

Animals↗
PubMed1996

Effects of OP 2507, a stable analogue of prostaglandin I2, on carbon tetrachloride-induced liver damage in starved rats.

It has been reported that vasodilatory prostaglandins have cytoprotective effects against various types of liver damage. We investigated the effects OP 2507, a stable analogue of prostaglandin I2, on carbon tetrachloride-induced liver damage in starved rats. Intraperitoneal administration of OP 2507 at 1,500 micrograms/kg lessened both an increase in serum alanine aminotransferase activity and an inhibition of starvation ketosis, both of which were induced by carbon tetrachloride. At lower doses, however, OP 2507 not only failed to ameliorate the carbon tetrachloride-induced changes, but it actually exaggerated them. Although the deterioration of carbon tetrachloride-induced liver damage by lower doses of OP 2507 was not statistically significant, it seems possible that OP 2507 has dual effects on carbon tetrachloride-induced liver damage. While none of the three agents cimetidine, reduced glutathione and deferoxamine, prevented increase in serum alanine aminotransferase activity induced with lower dose OP 2507, allopurinol had a tendency to prevent the increase, indicating that lower doses of OP 2507 may promote a reaction catalyzed by xanthine oxidase. We propose that both the co-administration of prostaglandins and other potentially hepatotoxic drugs, and the administration of prostaglandins to patients with drug-induced liver damage should be done carefully.

Alanine Transaminase↗
PubMed1996

Intraglomerular C3 synthesis in human kidney detected by in situ hybridization.

Complements 3 and 4 are known to be synthesized in diseased renal tissue and the mRNA of these complements has been demonstrated, using polymerase chain reaction, in renal biopsies from nephritic patients. However, the types of cells producing the complements in intact renal tissue have not been defined. To identify the renal cellular components involved in complement synthesis, we analyzed the expression of C3 mRNA in renal tissues from patients with immune-complex glomerulonephritis by a high-resolution in situ hybridization using digoxigenin-labeled oligonucleotide. Renal tissues from 15 patients with immunoglobulin (Ig) A nephropathy (IgAN), five with lupus nephritis (LN), and five with minimal change nephrotic syndrome (MCNS) were examined. Uninvolved portions of surgically removed kidney with tumors served as normal controls. C3 mRNA was detected in mesangial cells, glomerular epithelial cells, and Bowman's capsule in IgAN and LN. In the interstitium, some tubules and some infiltrating mononuclear cells were positively stained for C3 mRNA. C3 mRNA was not detected in MCNS and control tissues. Our results confirm that the glomerular resident cells can synthesize C3 in immune-mediated glomerulonephritis and suggest that locally synthesized complement may be involved in tissue injury in glomerulonephritis.

Biopsy↗
PubMed1996

Endogenous arachidonic acid inhibits hypotonically-activated Cl- channels in isolated rat hepatocytes.

Properties of hypotonically-activated Cl- channels in isolated rat hepatocytes were studied by the patch-clamp whole-cell technique. Hypotonic stress (140-150 mosmol kg 1 H2O) induced a hyperpolarization of the membrane of hepatocytes in the presence of an inwardly oriented Cl gradient, but had no effect on the membrane potential in the absence of Cl. An increase in the hypotonically-induced conductance was significantly inhibited by 4-acetamido-4'-isothiocyanatostilbene-2, 2'-disulfonic acid (SITS; 50 microM), but not by Ba2+ (1 mM). Pre-incubation with arachidonic acid (20 microM) significantly inhibited the hypotonically-activated conductance. The combined application of a cyclo-oxygenase inhibitor, indomethacin (50 microM) and a lipoxygenase inhibitor, esculetin (100 microM) also inhibited the conductance, whereas quinacrine (200 microM), a phospholipase A2 inhibitor, significantly induced a large steady conductance. Outward Cl- currents, but not cationic currents, were elicited by the hypotonic stress. The current did not show any rapid time-dependent inactivation during the voltage clamp of 0.1 s. The combined application of arachidonic acid, indomethacin and esculetin inhibited the hypotonically-activated Cl- currents. The present study has shown that the Cl- channel is activated by exposure to hypotonic stress and closed by an increase in arachidonic acid concentration in isolated rat hepatocytes.

Animals↗
PubMed1996

Inhibition of oxidation of low density lipoprotein by vitamin E and related compounds.

The oxidation of low density lipoprotein (LDL) was carried out aiming specifically at elucidating the anti-oxidant action of alpha-tocopherol. Lipophilic and hydrophilic azo compounds and copper induced the oxidation of LDL similarly to give cholesterol ester and phosphatidylcholine hydroperoxides as major products. The antioxidant potency of alpha-tocopherol in LDL was much poorer than in homogeneous solution. Doxyl stearic acids were used as spin probe and incorporated in LDL. The rate of reduction of doxyl nitroxide in LDL by ascorbate decreased with increasing distance from the LDL surface. From the competition between the spin probe and alpha-tocopherol in scavenging radical, it was found that the efficacy of radical scavenging by alpha-tocopherol became smaller as the radical went deeper into the interior of LDL. On the other hand, 2,2,5,7,8-pentamethyl-6-chromal spared the spin label regardless of the position of nitroxide. The antioxidant activity of chromanols against LDL oxidation increased with decreasing length of isoprenoid side chain at the 2-position. All these results were interpreted by location and low mobility of alpha-tocopherol in LDL. The tocopherol mediated propagation was observed notably at low rate of radical flux, but this was suppressed by reductant such as ascorbic acid and ubiquinol.

Amidines↗
PubMed1996

[Photodynamic therapy for multiple primary lung cancer].

In recent years, multiple primary lung cancers have been reported with greater frequency, partly as a result of technologic advances in the detection of lung cancer and therapeutic achievements in its management. As for the treatment of multiple primary lung cancer, operative excision is usually difficult for all lesions due to problems of pulmonary function. PDT is a good therapeutic modality in the treatment of multiple primary lung cancer, especially central type lung cancer, for preservation of lung function. Since 1980, 27 patients of multiple primary lung cancers have been treated with PDT at Tokyo Medical College. Fourteen of these 27 patients were synchronous with the rest, metachronous. Seven of 27 patients with multiple tumors had early-stage lesions and were treated with endoscopic PDT alone. In other 20 cases, PDT was used to treat accessible early-stage foci although operative excision was required for advanced lesions. Mean survival after PDT, alone or in combination with surgery, was 52 months (range, 5 to 162 months) and 16 patients remain alive to date. PDT is useful in extending the therapeutic options for, and improving the prognosis of patients with, multiple primary bronchogenic carcinomas.

Adenocarcinoma↗
PubMed1996

Monocyte superoxide generation and its IgA-receptor in IgA nephropathy.

Recent studies indicated that polymorphonuclear leukocytes (PMNL) were primed to produce superoxide (O2-) in various types of glomerulonephritis with a particular importance in IgA nephropathy (IgAN). In this study, we have examined O2- production and receptor expression for the Fc portion of IgA (Fc alpha R) in monocytes to evaluate their incorporation in IgAN, since infiltration of these cells in the glomeruli are more commonly observed than that of PMNL. Similar to PMNL, monocytes obtained from IgA nephropathy (IgAN) seemed to be primed both non-specifically and specifically, as increased O2- generation was observed to N-formyl methionyl leucyl phenylalanine (FMLP) and phorbol myristate acetate (PMA), as well as IgA aggregates stimulants, respectively. Monocytes O2- generation to IgA aggregates was comparatively higher in amount than in PMNL, and showed a correlation with the severity of proteinuria in IgAN patients. Flow cytometric assessment showed an increased expression of Fc alpha R on circulating monocytes in IgAN patients which showed a linear correlation with the amount of IgA-induced O2- generation. Comparing with the previous literature on PMNL, inflammation-related substances such as cytokines/immune complexes, particularly IgA immune complexes which present in the circulation of IgAN, can prime the phagocytic cells in the circulation for a burst of O2- generation to a second stimulus. The increased expression of Fc alpha R appears to be associated with the increase in priming and the degree of priming can be reflected in the severity of proteinuria/hematuria, although it can not be defined as a cause or consequence of this disease.

Adult↗
PubMed1996

[Anterior chamber dimensions in patients with angle-closure glaucoma measured by an anterior eye segment analysis system].

The corneal curvatures, iridocorneal angles, anterior chamber depths, and anterior chamber volumes in 26 (5 male and 21 female) patients with primary angle-closure glaucoma were measured using an anterior eye segment analysis system (EAS-1000, Nidek). The radius of corneal curvature was 7.65 +/- 0.25 mm (mean +/- standard deviation), significantly smaller than age-matched controls, and the iridocorneal angles ranged between 19 and 21 degrees. The anterior chamber depth and volume of angle-closure glaucoma eyes did not correlate with age; the depth averaged 1.90 +/- 0.41 mm, and the volume averaged 83.3 +/- 28.4 microliters.

Aged↗
PubMed1996

[Familial amyotrophic lateral sclerosis showing variable clinical courses with (Leu84-->Val) mutation of Cu/Zn superoxide dismutase].

A family with autosomal-dominant amyotrophic lateral sclerosis with histopathological confirmation on autopsy was described. A 42-year-old female proband showed the signs and symptoms only in the lower limbs characteristic of lower motor neuron involvement at the onset. ALS had been diagnosed in other five members in three generations of her family. The mean +/- SD age of onset of the disease was 42.5 +/- 9.3 years with a range of 30 to 51 years. The mean +/- SD duration of the disease (n = 5, excluding the proband) was 56 +/- 70 months with a range of 7 to 180 months. Molecular genetic studies showed a T-to-G transversion that results in the substitution of valine for leucine84 in exon 4 of the Cu/Zn superoxide dismutase (SOD) gene on chromosome 21 in a proband. This mutation is identical to that found in the Japanese family with autosomal-dominant ALS characterized by short duration of the disease, within 1.5 years, in all the affected family members. Therefore, the clinical phenotype, especially the duration of the disease seems to be highly variable even in the families with the identical mutation of the Cu/Zn SOD gene.

Adult↗
PubMed1996

[Late-onset adrenomyeloneuropathy perplexed with spondylosis. A case report].

We reported a 60-year-old man with late-onset adrenomyeloneuropathy (AMN). He had been well until 10 years before entry, when he noticed numbness in the legs with gait difficulty; symptoms worsened gradually with additional urinary disturbance. Transient improvement occurred after cervical and lumbar spinal operation under the diagnosis of spinal spondylosis, while his spastic gait got worse. Neurological examination on admission disclosed bilateral horizontal nystagmus, ataxic and spastic gait, increased patellar tendon reflexes, Chaddock sign, and impaired deep sense in the lower limbs with positive Romberg sign. Abnormal laboratory data included hypofunction of the adrenal cortex and elevated saturated very long chain fatty acids (VLCFAs). Serum cholestanol level was normal and anti-HTLV-1 antibody was negative. T2-weighted MRI showed a high signal intensity lesion in the occipital white matter along the optic radiation. Electrophysiological tests suggested a brainstem lesion on auditory brainstem response, thoracic or lumbar lesion on somatosensory evoked potential, and peripheral neuropathy on nerve conduction study. In the present case, it should be emphasized that the determination of serum VLCFAs unveiled the diagnosis of AMN in old patients with spinal spondylosis or without apparent clinical symptoms of adrenocortical insufficiency.

Adrenoleukodystrophy↗
PubMed1996

Molecular analysis of glomerular diseases in renal biopsies: initial results of a collaborative international study. The International Study Group for Molecular Study of Kidney Biopsies.

An accurate assessment of which patient with glomerular disease will progress to end-stage renal failure would be an important addition to establishing prognosis and evaluating therapeutic strategies. We previously found the development of glomerular scarring in animal models was preceded by an increase in glomerular type IV collagen mRNAs and that the level of scarring predicted the rate of progression. The purpose of this study was to determine whether these findings apply to human glomerular diseases using microdissected glomeruli and assessment of mRNA by competitive PCR. After showing that the levels of type IV collagen mRNAs were elevated in sclerotic glomeruli isolated from nephrectomies, we undertook this preliminary cross-sectional study of type IV collagen subchain mRNAs in renal biopsies in two of the leading causes of glomerulosclerosis, diabetic nephropathy, and membranous glomerulopathy. We found that glomerular type IV collagen mRNA levels were altered in disease-specific ways. The relative levels of the individual alpha-chains of type IV collagen depended on the anatomic site of the glomerular lesions. The alpha 2 type IV/alpha 3 type IV collagen mRNA ratio was high in diabetes mellitus, but not in membranous glomerulopathy. These data, coupled with those obtained from experimental animals, suggest that a dysregulation of basement collagen synthesis underlies progressive glomerular scarring. If these conclusions are verified in prospective studies it will be feasible to assess the risk of developing progressive glomerulosclerosis in the individual patient and to quantitatively assess therapeutic responses in a timely manner.

Aged↗
PubMed1996

[Surgical treatment of pericostal tuberculosis].

The following two points must be considered on treating pericostal tuberculosis: the first is the appropriate time to treat pericostal tuberculosis surgically when the medical therapy fails to induce a remission, and the second is how to prevent postoperative relapse. In the present study, we investigated these two points by examining seven patients who underwent surgery at the department of thoracic surgery (Osaka Red Cross Hospital), during a 10 years period from January 1985 to December 1994. Antituberculotics were administered to these patients for an average of 3.9 months before surgery, but in vain. Therefore, they were surgically treated. In all cases, the incision was closed at once, and there were no severe complications. The signs and symptoms disappeared soon after surgery. It has been reported that the medical treatment leads to recovery or tendency to recovery within three months of drug administration. The conditions of pericostal tuberculosis patients during this period can be used as indicators to decide whether or not to carry out surgical treatment. Also, by active excision of the rib and tumor as one mass, and by administering antituberculotic for 13.1 months after surgery, no relapse took place during the follow-up period (average 37.4 months). And the postoperative respiratory functions did not decrease compared to those before surgery.

Adult↗