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Biomedical subjects

T Baba

Publications and source records attributed to T Baba.

At least 127 records · Page 7Linked to original sources
PubMed1999

Angiotensin-converting enzyme inhibition restores hepatocyte growth factor production in patients with congestive heart failure.

Endothelium-dependent vasodilation is impaired in patients with congestive heart failure. For vascular endothelium, hepatocyte growth factor (HGF) is one of the most potent and specific growth factors, which acts protectively against endothelial dysfunction. HGF production is downregulated by angiotensin II (Ang II) in vitro. We hypothesized that HGF production is impaired as the result of increased Ang II in patients with congestive heart failure, and that if so, the impaired production should be restored with angiotensin-converting enzyme inhibitors (ACE-I). We studied 16 patients with congestive heart failure caused by previous anterior myocardial infarction in whom left ventricular ejection fraction was 35+/-8% (mean+/-SD). Before and approximately 4 weeks after the treatment with ACE-I, blood samples were collected to measure the levels of HGF, Ang II, and brain natriuretic peptide as a biochemical marker for severity of heart failure. We also studied 5 control subjects, in whom heparin increased HGF production to 48+/-5-fold. However, in patients with heart failure, HGF response to heparin was significantly attenuated (24+/-5-fold, P<0.05 vs control). Therapy with ACE-I decreased the levels of Ang II and brain natriuretic peptide and restored HGF production in response to heparin by 43+/-7-fold, comparable to the control response. In conclusion, impaired HGF production was restored after the treatment with ACE-I probably by the mechanism of Ang II suppression. This novel effect of ACE-I may contribute to the clinical improvement in patients with heart failure and thereby may have an important therapeutic implication.

Aged↗
PubMed1999

Immunocytochemical study of endocytotic structures accumulated in HeLa cells transformed with a temperature-sensitive mutant of dynamin.

Dynamin is a 100-kD GTPase, which is required for clathrin-mediated endocytosis. Recent studies have revealed that dynamin is closely involved in clathrin-coated vesicle formation. In this study we investigated the ultrastructure of endocytotic structures accumulated in HeLa cells that were transformed with a temperature-sensitive (ts) mutant of dynamin to clarify which step was blocked in dynts cells. Endocytosis of transferrin receptors was restricted at the level of surface-connected membrane structures. Tubular and vesicular membrane invaginations were accumulated in the cells' peripheral regions, suggesting that the endocytosis was blocked just before the pinching-off steps in coated vesicle formation. The "collared" tubes, which were reported to be localized in nerve terminals in shibirets1 flies and GTPgammaS-treated synaptosomes, were not observed in the dynts cells even at nonpermissive temperature. The distribution pattern of dynamin in deeply invaginated coated pits in dynts cells was similar to that in dynwt cells but not to that in dynK44A cells, which are other endocytosis-defective mutant cells. These morphological data suggest that dynts blocked the pinching-off steps in clathrin-coated vesicle formation, which may be caused by a different mechanism from that of dynK44A cells.

Cell Membrane↗
PubMed1999

Does coronary artery morphology predict favorable results of intracoronary thrombolysis in patients with unstable angina pectoris?

The efficacy of intracoronary thrombolysis (ICT) for unstable angina pectoris (UAP) has been limited, despite the similar pathogenesis between UAP and acute myocardial infarction. To ascertain the subset of UAP suitable for ICT, the clinical responses to ICT were assessed in patients with UAP. Eighty-2 patients with medically refractory angina were divided into 2 groups according to the coronary artery morphology of the culprit lesion before ICT: (1) lesions with acute cut off and/or filling defects (AC) and (2) lesions with a tapered shape (TA). The TIMI flow grade was determined from coronary angiograms before and immediately after ICT. The diameter stenosis (%DS) and minimal lumen diameter (MLD) of the culprit lesion were determined using quantitative coronary angiographic analysis before and immediately after ICT. In addition, inhospital cardiac event rates including urgent/emergency coronary angioplasty or bypass surgery, nonfatal myocardial infarction or cardiac death were compared between the 2 groups. Multivariate logistic regression analysis was performed using 13 clinical factors contributing to successful ICT. The results showed that all 3 coronary angiographic parameters (TIMI flow, %DS, and MLD) significantly improved in the AC group (p<0.01, p<0.01 and p<0.05, respectively), whereas none of these parameters improved in the TA group. The inhospital cardiac event rate after ICT was significantly higher in the TA group (76%) than in the AC group (48%; p=0.016). Odds ratio predicting successful ICT was 7.09 (p<0.01) for the AC lesion, and 2.54 (p<0.01) for new angina. In conclusion the AC lesions are more commonly associated with coronary thrombosis that responds to ICT than are the TA lesions. Thus, the coronary angiographic morphology may be an important predictor for a successful ICT in patients with medically refractory UAP.

Aged↗
PubMed1999

Neurally mediated syncope and arrhythmias: a study of syncopal patients using the head-up tilt test.

Understanding the causes of syncope in patients with arrhythmia is important in determining the therapeutic interventions. Neurally mediated syncope (NMS) was evaluated in 55 patients with various arrhythmias. The head-up tilt test with or without isoproterenol infusion induced NMS in 41 (74%) patients. When these patients was categorized into 3 types, depending on the development of syncope, vasodilatation was significant in a majority of patients. In 46% of patients with tachyarrythmias, NMS was accompanied by an increase in extrasystole. It was concluded that the evaluation of vasodilatation is important for the preventive strategy of NMS in patients with arrhythmias and that NMS may induce arrhythmias.

Arrhythmias, Cardiac↗
PubMed1999

MR imaging of squamous cell carcinoma of the floor of the mouth. Appearance of the sublingual and submandibular glands.

PURPOSE: To determine the diagnostic value of MR imaging for tumors of the floor of the mouth and the effects of the tumors on the sublingual and submandibular glands. MATERIAL AND METHODS: Thirty-seven patients with proven squamous cell carcinoma of the floor of the mouth underwent MR imaging, including unenhanced T1-weighted, T2-weighted, dynamic, and contrast-enhanced T1-weighted images. The appearance of the tumor and the sublingual and submandibular glands was assessed qualitatively and quantitatively. RESULTS: All tumors demonstrated replacement of the normal signal intensity in the adjacent sublingual gland. Twenty-one patients (57%) had abnormal signal intensity of the submandibular gland without tumor invasion, presumably secondary to submandibular duct obstruction by the tumor. Unenhanced T1-weighted images provided high contrast between tumor and sublingual gland. Tumors limited within the gland were well detected on unenhanced T1-weighted images. Large tumors extending beyond the gland were well delineated on dynamic images, but no better than on T2-weighted images. CONCLUSION: At MR imaging for tumor of the floor of the mouth, one must carefully evaluate the appearance of the sublingual and submandibular glands. Contrast-enhanced studies are unnecessary when the tumor is limited within the sublingual gland on precontrast MR images.

Adult↗
PubMed1998

Characterization of alkaline phosphatase genes expressed in seminoma by cDNA cloning.

Two members of a placental alkaline phosphatase (PLAP) family, PLAP and PLAP-like or germ cell alkaline phosphatase, are aberrantly expressed in tumors of ecotropic origin. To characterize alkaline phosphatase induced in seminoma, alkaline phosphatase cDNA clones were isolated from a cDNA library constructed from seminoma cells and characterized by nucleotide sequence determination. Thus, isolated cDNA clones were classified into two types, germ cell alkaline phosphatase (PLAP-like) and liver/bone/kidney-type alkaline phosphatase (L/B/K AP). These results suggest that other than the PLAP family members, the expression of L/B/K AP is enhanced in seminoma and can serve as a tumor marker in seminoma.

Alkaline Phosphatase↗
PubMed1998

Ophthalmological findings in patients with Takayasu disease.

We examined 65 (61 female and 4 male) Takayasu patients. Patient age ranged from 17 to 78 years old (mean 50.2); age of onset was from 11 to 60 years old (mean 32.8); and duration from onset to referral ranged from 1 month to 43 years (mean 16.8 years). Routine ophthalmological examinations were performed. Fluorescein angiography, kinetic perimetry by Goldmann perimetry, static perimetry by Octopus 1-2-3, electroretinography (ERG), and measurements of central retinal arterial pressure were also performed, as appropriate. Major causes of impaired visual acuity (less than 16/20) were cataract. A few patients had low visual acuity caused by Takayasu disease itself. On the other hand, although not many complained of visual disturbance, about 35% of patients had subnormal visual functions. Because the visual deterioration may be based on ocular hypoperfusion, which may subsequently lead to more serious changes, regular ophthalmological examination for every Takayasu disease patient is recommended.

Adolescent↗
PubMed1998

Targeting of muralytic enzymes to the cell division site of Gram-positive bacteria: repeat domains direct autolysin to the equatorial surface ring of Staphylococcus aureus.

Staphylococcus aureus secretes autolysin (Atl) to complete cell division by hydrolyzing its thick cell wall layer at a designated site, known as the equatorial surface ring. Secreted pro-Atl (1256 amino acids) is cleaved at residues 198 and 775 to generate a pro-peptide, amidase and glucosaminidase, respectively. Here we examined the mechanism that directs amidase and glucosaminidase to the cell division site on the staphylococcal surface. Targeting of pro-Atl to the cell surface occurred prior to its proteolytic processing. Three repeat domains (R1, R2 and R3) located at the center of pro-Atl are necessary and sufficient for the targeting of reporter proteins to the equatorial surface ring. Pro-Atl cleavage at residue 775 separates the polypeptide such that R1 and R2 are linked to the C-terminus of amidase, whereas R3 is located at the N-terminus of glucosaminidase. Thus, it appears that the repeat domains direct pro-Atl, amidase and glucosaminidase to a specific receptor at the equatorial surface ring of staphylococci, thereby allowing localized peptidoglycan hydrolysis and separation of the dividing cells.

Base Sequence↗
PubMed1998

Optimal image resolution for digital storage of radiotherapy-planning images.

PURPOSE: To evaluate the quality of digitized radiation-planning images at different resolution and to determine the optimal resolution for digital storage. METHODS AND MATERIALS: Twenty-five planning films were scanned and digitized using a film scanner at a resolution of 72 dots per inch (dpi) with 8-bit depth. The resolution of scanned images was reduced to 48, 36, 24, and 18 dpi using computer software. Image qualities of these five images (72, 48, 36, 24, and 18 dpi) were evaluated and given scores (4 = excellent; 3 = good; 2 = fair; and 1 = poor) by three radiation oncologists. An image data compression algorithm by the Joint Photographic Experts Group (JPEG) (not reversible and some information will be lost) was also evaluated. RESULTS: The scores of digitized images with 72, 48, 36, 24, and 17 dpi resolution were 3.8 +/- 0.3, 3.5 +/- 0.3, 3.3 +/- 0.5, 2.7 +/- 0.5, and 1.6 +/- 0.3, respectively. The quality of 36-dpi images were definitely worse compared to 72-dpi images, but were good enough as planning films. Digitized planning images with 72- and 36-dpi resolution requires about 800 and 200 KBytes, respectively. The JPEG compression algorithm produces little degradation in 36-dpi images at compression ratios of 5:1. CONCLUSION: The quality of digitized images with 36-dpi resolution was good enough as radiation-planning images and required 200 KBytes/image.

Humans↗
PubMed1998

Three-dimensional ultrastructure of apoptotic nuclei in rat prostatic epithelial cells revealed by a quick-freezing and deep-etching method.

BACKGROUND: To clarify intranuclear apoptotic changes, we have investigated chromatin organization in apoptotic nuclei of castrated rat prostatic cells by a quick-freezing and deep-etching (QF-DE) method. METHODS: The ventral prostates taken from intact and castrated adult male rats were investigated by light microscopy, in situ end-labeling (ISEL) technique, conventional electron microscopy, and the QF-DE method. RESULTS: In control nuclei, the chromatin fibers were uniformly distributed and formed a network structure. In apoptotic nuclei, destruction of such chromatin networks was detected, which was clearly seen by the QF-DE method. Although it first appeared spotty in the apoptotic nucleus, definite destruction of the intranuclear network occurred in the nuclear center at later stages, and broken fibrous structures were condensed along the nuclear margin. The ISEL technique was applied to the QF-DE method. Localization of damaged DNA fragments could three-dimensionally be detected on replica membranes. CONCLUSIONS: Intranuclear chromatin organization in apoptotic cell death of rat prostates was observed by the QF-DE method. We could examine early-stage apoptotic nuclei at an electron microscopic level, which would not be clarified by other conventional methods.

Animals↗
PubMed1998

Two novel testicular serine proteases, TESP1 and TESP2, are present in the mouse sperm acrosome.

To identify a novel candidate(s) for acrosomal proteins that act on the sperm/egg interaction, a DNA fragment was PCR-amplified from a cDNA library of acrosin-deficient mouse testis and then used as a probe to screen a mouse testis cDNA library. Complementary DNA clones encoding each of two similar but different serine proteases, TESP1 and TESP2, have been identified. The nucleotide sequences of these clones indicate that mouse TESP1 and TESP2 are initially synthesized as preproproteins of 367 and 366 amino acids, respectively. Comparison of the two TESP sequences with those of typical serine proteases suggests that each TESP zymogen is probably converted into a two-chain mature enzyme consisting of light and heavy chains covalently linked by a single pre-existing disulfide bond. The conversion may be accomplished by another protease(s) with a trypsin-like cleavage specificity, since it is unlikely that the mature TESP1 and TESP2 are capable of splitting the Lys-Ile bond between the light and heavy chains. Northern blot analysis of total cellular RNA demonstrates that the TESP1 and TESP2 genes are expressed only in the testis, and the transcripts are abundantly present in the haploid round spermatids. Moreover, immunocytochemical analysis of mouse cauda epididymal sperm using affinity-purified antibodies reveals that these two TESPs are both localized in the sperm acrosome and are released during the acrosome reaction induced by calcium ionophore A23187. These findings provide additional clues for elucidating the mechanisms involved in the sperm/egg interactions, including penetration of the zona pellucida by sperm.

Acrosome↗
PubMed1998

Acrosin accelerates the dispersal of sperm acrosomal proteins during acrosome reaction.

Using homologous recombination, we have previously produced male mice carrying a disruptive mutation (Acr-/-) in the acrosin gene. Although Acr-/- mouse sperm lacking the acrosin protease activity still penetrated the zona pellucida and fertilized the egg, the mutant sperm exhibited a delay in penetration of the zona pellucida solely at the early stages after insemination. To further elucidate the role of acrosin in fertilization, we have examined the involvement of acrosin in the acrosome reaction of sperm using the Acr-/- mutant mice. When the ability of sperm to adhere (attach) and bind to the zona pellucida of cumulus-free eggs was assessed in vitro, no significant difference was observed among Acr+/+, Acr+/-, and Acr-/- mouse sperm. Immunocytochemical analysis demonstrated that the release of several acrosomal proteins from the acrosome of Acr-/- mouse sperm was significantly delayed during the calcium ionophore- and solubilized zona pellucida-induced acrosome reaction, despite normal membrane vesiculation. These data indicate that the delayed sperm penetration of the zona pellucida in the Acr-/- mouse results from the altered rate of protein dispersal from the acrosome and provide the first evidence that the major role of acrosin is to accelerate the dispersal of acrosomal components during acrosome reaction.

Acrosin↗
PubMed1998

Cloning and characterization of a cDNA fragment coding beta-casein-like protein preferentially expressed in cervical adenocarcinoma cell line CAC-1.

We generated new murine monoclonal antibodies against bovine beta-casein. One of eight new monoclonal antibodies generated, 12G2, specifically reacted not only with beta-casein, but also with human cervical adenocarcinoma cell line CAC-1. To identify the gene encoding the putative protein (BCLP) defined by monoclonal antibody (mAb) 12G2, a complementary DNA library was constructed. We obtained the inserted cDNA fragment that showed high homology to reported DNA sequences of unknown function in normal human placenta. We think that BCLP was overexpressed or changed its structure by carcinogenesis.

Adenocarcinoma↗
PubMed1998

Elevation of serum human hepatocyte growth factor (HGF) level in patients with pneumonectomy during a perioperative period.

OBJECTIVE: Proliferation of alveolar type II cells is thought to be critical for the restoration of lung function after diffuse alveolar damage or pneumonectomy. However, the factors that regulate alveolar type II cell proliferation, and the mechanism that brings about compensatory lung growth are not well understood. Hepatocyte growth factor (HGF) has been shown to have hepatotrophic and nephrotrophic functions for regeneration of the liver and kidney. We have attempted to investigate the involvement of HGF in lung regeneration after lung resection. DESIGN: A prospective, controlled study. SETTING: Adult surgical patients in a university hospital. PATIENTS AND MEASUREMENTS: We measured serum HGF levels in eight patients undergoing major lung resection, and in five patients undergoing mastectomy as controls, by using radioimmunoassay and an enzyme-linked immunosorbent assay. RESULTS: In all cases of pneumonectomy, the serum HGF levels increased 3- to 5-fold at 1-3 days (with a peak at 3 days) after operation, and then decreased to nearly basal levels in 2 weeks. However, these levels in patients undergoing mastectomy did not change much over the first 2 weeks, postoperatively. CONCLUSIONS: Serum HGF levels increased in patients after major lung resection, which suggests that HGF might play an important role in lung regeneration or compensatory lung growth in humans.

Analysis of Variance↗