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Biomedical subjects

T Baba

Publications and source records attributed to T Baba.

At least 217 records · Page 12Linked to original sources
PubMed1996

A 718-kb DNA sequence of the Escherichia coli K-12 genome corresponding to the 12.7-28.0 min region on the linkage map.

The 718,122 base pair sequence of the Escherichia coli K-12 genome corresponding to the region from 12.7 to 28.0 minutes on the genetic map is described. This region contains at least 681 potential open reading frames, of which 277 (41%) have been previously identified, 147 (22%) are homologous to other known genes, 139 (20%) are identical or similar to the hypothetical genes registered in databases, and the remaining 118 (17%) do not show a significant similarity to any other gene. In this region, we assigned a cluster of cit genes encoding multienzyme citrate lyase, two clusters of fimbrial genes and a set of lysogenic phage genes encoding integrase, excisionase and repressor in the e14 genetic element. In addition, a new valine tRNA gene, designated valZ, and a family of long directly repeated sequences, LDR-A, -B and -C, were found.

DNA, Bacterial↗
PubMed1996

Boar proacrosin expressed in spermatids of transgenic mice does not reach the acrosome and disrupts spermatogenesis.

Transgenic mice that express boar proacrosin were produced to examine mechanisms for targeting hydrolytic enzymes to the acrosome. A 2.3 kb transgene was constructed by ligating the cDNA for boar preproacrosin with the mouse protamine 2 promoter region. Six founder mice that incorporated the transgene were identified by polymerase chain reaction and Southern blot analysis. Northern blots indicated that the two male founders (Ac.2 and Ac.5) and male progeny from three female founders (Ac.3, Ac.4, Ac.6) expressed the transgene mRNA in testis, but not in somatic tissues. In these transgenic animals boar proacrosin was detected by immunohistochemistry in condensing spermatids, but was not localized in the acrosome. This acrosomal targeting defect of the transgene product may result from its delayed expression during the later steps of haploid differentiation. Furthermore, both male founders and all Ac.4 and Ac.6 males were infertile, as determined by multiple matings for at least 2 months. Ac.3 males were either infertile or rarely transmitted the transgene to their offspring. The infertile males mated, produced copulatory plugs, and had seminal vesicle weights and testosterone levels within the normal range. However, they produced significantly fewer spermatozoa and had lower testis weights than controls. Although the mitotic and meiotic phases of spermatogenesis appeared normal by histological criteria, condensing spermatids were missing from most tubules, and multinucleated cells were present in the lumen of seminiferous tubules and in the epididymis. We hypothesize that boar proacrosin which fails to reach the acrosome is activated in these transgenic mice, and that its proteolytic activity disrupts spermatogenesis during spermatid formation.

Acrosin↗
PubMed1996

Determination of enamel protein synthesized by recombined mouse molar tooth germs in organ culture.

Epithelial-mesenchymal interaction is a prerequisite for tooth morphogenesis. To study this interaction, inner enamel epithelium and dental papilla mesenchyme of molar tooth germs from a 16.5-day mouse embryo were dissociated enzymatically and cultured alone or after recombination. Characteristic matrix protein synthesized and secreted by recombined tooth germ was determined quantitatively by enzyme-linked immunosorbent assay. The protein was detected in the culture of recombined tooth germ but not of dissociated enamel epithelium alone. The amount of enamel protein increased until 8 days in culture. Morphological differentiation of the recombined epithelial rudiment into ameloblasts and enamel protein production were confirmed.

Ameloblasts↗
PubMed1996

An acetophenone glycoside from Exacum affine.

A new acetophenone glycoside, affinoside, was isolated from the aerial parts of Exacum affine and its structure was determined as 2-O-primeverosylpaenol. The known glucosides, gentiopicroside, 2'-O-E/Z-p-coumaroylloganin and glucopaeonol, were also identified.

Acetophenones↗
PubMed1996

Inhibition of cytotoxic activity of carp lymphocytes (Cyprinus carpio) by anti-thymocyte monoclonal antibodies.

A series of monoclonal antibodies (mAbs) were developed against carp thymocytes and carp immunoglobulin (IgM). Anti-thymocyte mAbs reacted with thymocytes, head kidney lymphocytes (HKL) as well as peripheral blood lymphocytes (PBL) at various proportions. Anti-IgM antibody reacted with HKL and PBL but not with thymocytes. PBL from carp immunized with xenogeneic mouse myeloma cells exhibited cytotoxic activity against target cells but PBL from unimmunized fish showed weak cytotoxicity. Treatment of PBL with anti-thymocyte mAbs and guinea pig complement suppressed the cytotoxic activity dose dependently; however, anti-IgM mAb did not. These results indicate the cytotoxic cells in PBL possess cell surface antigens common to thymocytes.

Animals↗
PubMed1996

The study of ultraviolet B-induced apoptosis in cultured mouse keratinocytes and in mouse skin.

The responsibility of ultraviolet B (UVB) radiation for the induction of apoptosis in epidermal cells in vitro and in vivo was examined. Using cultured mouse keratinocytes, PAM212 cells, the morphological development of apoptotic cells (AC) after UVB irradiation was observed, and their DNA status was also examined. In addition, histochemical analysis was performed to establish whether the UVB-mediated sunburn cells (SBC) were AC or not. The cultured cells exposed to UVB showed the morphological characteristics of AC, and the electrophoresis of DNA isolated from these cells showed characteristic fragmentation, i.e. 'DNA ladder'. DNA fragmentation was detectable with UVB doses of more than 50 mJ/cm2, and it appeared 12 h after irradiation, indicating endonuclease-mediated DNA damage. In vivo experimentation using the TdT-mediated dUTP-biotin nick end labeling method (TUNEL) for detection of AC showed scattered positive cells in the basal layer of the UVB-irradiated mouse ear skin. The distributed pattern of the TUNEL-positive cells was similar to that of SBCs. These findings suggest that UVB is a causative factor of apoptosis in the epidermal cells, and that SBC is formed as a result of the apoptosis.

Animals↗
PubMed1996

Cell biology of kidney glomerulus.

It has been accepted that some artifacts are inevitably produced by the conventional preparation steps for electron microscopy, including fixation, dehydration, embedding, ultrathin sectioning, and staining. Therefore, conventional ultrastructural findings on kidney glomeruli are hardly thought to be correlated with the physiological functions of kidneys in vivo. In this chapter, two preparation techniques, the quick-freezing and deep-etching (QF-DE) method or the quick-freezing and freeze-substitution (QF-FS) method, are presented and shown to be useful for clarifying the ultrastructures of kidney glomeruli more closely to structures in vivo with fewer artifacts. Moreover, the ultrastructures of glomerular capillary loops have been demonstrated by a new "in vivo cryotechnique," that shows that hemodynamic factors should be considered in the morphological study of glomerular functions.

Animals↗
PubMed1996

A case of von Recklinghausen's disease with bilateral pheochromocytoma-malignant peripheral nerve sheath tumors of the adrenal and gastrointestinal autonomic nerve tumors.

A 48-year-old man with neurofibromatosis type 1 presented with chest pain, paroxysmal hypertension, tachycardia, and progressive respiratory insufficiency. Clinical investigation displayed calcified tumors in the anterior mediastinum and pararenal region. Histological examination at autopsy revealed composite tumors consisting of pheochromocytoma and malignant peripheral nerve sheath tumor (MPNST) at two sites: the left adrenal gland and the region surrounding the inferior vena cava, probably corresponding to the right adrenal gland. The MPNST component showed a varied histological appearance, including hyalinized bands with polygonal cells, a cartilaginous and myxoid stroma, a hemangiopericytomatous architecture, and a fibrosarcomatous structure, which suggested osteosarcoma, chondrosarcoma, angiosarcoma, and fibrosarcoma, respectively. In addition, based on the ultrastructural findings, the gastrointestinal tract was involved with mesenchymal tumors showing neurogenic differentiation. These lesions suggest the divergent cellular differentiation of neural crest-derived cells to mesenchymal elements as well as neuroectodermal neoplasms.

Adrenal Gland Neoplasms↗
PubMed1996

Successful treatment of mucosal melanosis of the lip with normal pulsed ruby laser.

Melanosis of the lip is not rare in Orientals. Although it causes cosmetic problems, treatment of this pigmentary disorder is often neglected because a satisfactory tool for complete removal of mucosal melanosis has not yet been developed. The pulsed ruby laser, which has a wavelength of 694 nm and a short pulse duration of 1-2 msec, selectively damages pigmented cells in the skin. In this study, six Japanese patients with labial melanosis, manifested as labial lentigo and Peutz-Jeghers syndrome, were successfully treated with the pulsed ruby laser. The therapy achieved rapid results without producing changes in mucosal texture or recurrence after operation.

Adolescent↗
PubMed1996

Synthesis and cytotoxic activity of dextran carrying cis-dichloro(cyclohexane-trans-l-1,2-diamine)platinum(II) complex.

cis-Dichloro(cyclohexane-trans-l-1,2-diamine)platinum(II) (Dach-Pt(chlorato)), is a platinum complex which is expected to exhibit higher antitumor activity than, and show no cross resistance with, cisplatin. However, its strong side-effects and low water-solubility have also been cited. We report that polymer/antitumor drug conjugates shows reduced side-effects and high antitumor activity. In order to provide a macromolecular prodrug of Dach-Pt having reduced side-effects and high water-solubility, we synthesized polymer conjugates of Dach-Pt and dextran derivatives having carboxylic acid groups, oxidized-dextran (OX-Dex)/Dach-Pt conjugate, and carboxymethyl-dextran(CM-Dex)/Dach-Pt conjugate. The cytotoxic activities of the conjugates were investigated against p388D1 lymphocytic leukemia cells in vitro. The OX-Dex/Dach-Pt conjugate showed almost the same level of cytotoxic activity as free Dach-Pt(chlorato). Although the cytotoxic activity of free Dach-Pt(chlorato) was decreased by incubation in medium with serum, the OX-Dex/Dach-Pt conjugate kept its cytotoxic activity in higher level after 24 h incubation in medium with serum. These results suggested that the stability of Dach-Pt molecule in the medium was increased and cytotoxic activity of Dach-Pt was not decreased by fixing to OX-Dex.

Animals↗
PubMed1996

Dipyridamole suppresses catecholamine- and Ca++ influx-sensitive ventricular arrhythmias.

To study the mechanism of ventricular arrhythmias, the effect of dipyridamole (DIP; 300 mg/day), an adenosine transport inhibitor, on ventricular premature contractions (VPCs) was assessed in 12 patients who showed VPCs (21312 +/- 12314/day) on Holter ECG in a controlled setting. The effects were compared with those of verapamil (240 mg/day) and bisoprolol (5 mg/day). DIP suppressed more than one-half the VPCs in 5 patients. The mean degree of reduction in these DIP-responders was 75 +/- 18%. Both verapamil and bisoprolol inhibited VPCs in all of the DIP-responders (verapamil: 71 +/- 15%, bisoprolol: 88 +/- 16%). Two of the 5 DIP-responders had sustained ventricular tachycardias (VT) that were terminated by intravenous DIP, ATP, acetylcholine, verapamil, and propranolol. In contrast, verapamil did not inhibit VPCs in any of the DIP-nonresponders. Bisoprolol also did not suppress VPCs in 3 of 6 DIP-non responders. heart rate was unaffected by DIP, but was suppressed by both verapamil and bisoprolol. In addition, DIP increased the serum concentration of adenosine (control 16.3 +/- 17.1 vs 22.3 +/- 19.0 pmol/ml after DIP, p < 0.05). The inhibitory effect of DIP may involve suppression of Ca+2 current through an extracellular increase in adenosine.

Adult↗
PubMed1996

Selective slow pathway ablation in atrioventricular nodal reentrant tachycardia--comparison of different methods and the site of slow pathway ablation.

The optimum potential of the slow pathway (SP) was investigated by determining the effectiveness and safety of high-radiofrequency catheter ablation to treat atrioventricular nodal reentrant tachycardia (AVNRT). The subjects consisted of 29 patients with AVNRT (11 men, with a mean age of 54 +/- 15 years). Three ablation methods were used: a) Method A used the earliest atrial activation site, which is retrograde to the slow pathway, b) Method SP used the SP potential, and c) Method SW, in which ablation was performed stepwise starting from the coronary sinus and moving toward the recording site of the His bundle potential. Five, 20, and 4 patients underwent Methods A, SP, and SW, respectively. The fewest number of applications was needed with Method SP (11 +/- 9, 6 +/- 4, and 13 +/- 9), and the delivered energy was also lowest with Method SP (9151 +/- 6119, 3712 +/- 2168, and 12183 +/- 4090 J, with Methods A, SP, and SW, respectively). In Method SP, the interval between the atrium and SP was significantly longer at sites which cured tachycardia, than at sites at which ablation was ineffective (88 +/- 26 vs 66 +/- 22 msec, p < 0.05). The SP potential showed a humped shape in 18 of 20 patients. Method SP was the most efficient ablation method for treating AVNRT.

Adult↗
PubMed1996

Detection of Salmonella DNA in chicken embryos and environmental samples by polymerase chain reaction.

By polymerase chain reaction (PCR) using a pair of primers specific for Salmonella phoE gene a 365-bp specific gene fragment could be amplified from yolk of infertile eggs and dead-in-shell chicken embryos, and from environmental samples. Out of 45 dead-in-shell embryo samples, 20 (44.4%) were found positive for Salmonella DNA by PCR compared to 11 (24.4%) by bacteria isolation. Salmonella DNA could also be detected from infertile eggs, chicken faeces, floor litter and chick fluff, which incidence was higher than that by bacteria isolation.

Animals↗
PubMed1996

Is ACE gene polymorphism a useful marker for diabetic albuminuria in Japanese NIDDM patients?

OBJECTIVE: We studied the relationship between an insertion/deletion (I/D) polymorphism in the ACE gene and albuminuria/proteinuria in Japanese NIDDM patients. RESEARCH DESIGN AND METHODS: A total of 142 Japanese NIDDM patients (89 men, 53 women) with a known diabetes duration of 14 +/- 5 (mean +/- SD) years and an age of 56 +/- 6 years were divided into three groups according to the stage of nephropathy: 41 patients with normoalbuminuria, 47 patients with microalbuminuria, and 54 with overt proteinuria. The three groups were similar in age, diabetes duration, and recent HbAic level. RESULTS: The distribution of DD, ID, and II genotypes of the ACE gene did not differ among the three groups (10, 46, and 44% in the normoalbuminuric patients; 13, 53, and 34% in the microalbuminuric patients; and 15, 46, and 39% in the proteinuric patients, respectively). Meanwhile, the frequency of the D allele in the proteinuric male patients was slightly higher than in the normoalbuminuric male patients (45 vs. 27%, chi 2 = 3.9, P < 0.05), while the D allele frequency was nonsignificantly lower in the proteinuric female patients than in the normoalbuminuric female patients. CONCLUSION: These results did not support the hypothesis that the genotype of the ACE gene would be a clinically useful genetic marker for predicting the development of nephropathy in Japanese NIDDM patients. However, the role of D allele of ACE gene in the progression of nephropathy in male patients remains to be seen.

Albuminuria↗