Biomedical subjects

H Nagata

Publications and source records attributed to H Nagata.

At least 127 records · Page 7Linked to original sources

PubMed1998

[Renal damage in a chronic active hepatitis C patient receiving interferon-alpha therapy].

A 68-year-old male patient with chronic active hepatitis C was treated with interferon-alpha (IFN-alpha) for a period of 5 months. The patient responded well to the IFN therapy showing substantial improvement in liver function and disappearance of HCV-RNA. However, one year after the treatment he was found to have developed proteinuria and showed a reduction in Ccr. Renal biopsy findings were as follows: Light microscopy showed diffuse expansion of mesangial cells with a focal/local increase in cellularity accompanied by capillary loop thickening. Splitting of the basement membrane was also present. An immunofluorescent study showed that IgA was localized predominantly in the peripheral capillary wall. Electron microscopy showed that there was mesangial cell interposition between the peripheral capillary wall and endothelial cells. Furthermore, endothelial cells were expanded and numerous platelets were seen in the capillary lumen. These findings were compatible with focal MPGN accompanied by activation of endothelial cells. These histological data suggest two clinical disease entities: late-onset renal damage induced by IFN-alpha alone, and HCV-induced renal damage possibly modified by the direct effect of IFN-alpha on the endothelium. The present case suggests that IFN therapy for HCV may produce a particular type of renal damage, under the influence of either IFN or HCV infection, and/or both.

Aged↗

PubMed1998

[Clinical efficacy of MRCP for diagnosis of patients with pancreatic neoplasm].

We examined the usefulness of MRCP in pancreatic cancer compared with ERCP. Moreover, it examined in the same way in focal pancreatitis, too. We compare three findings of 1) main pancreatic duct, 2) branches of the stricture part, 3) side of tail main pancreatic duct about ERCP and MRCP. As for the branches of the stricture part, MRCP was poor compared with ERCP but as for the property of the side of the tail main pancreatic duct, MRCP excelled. The study of mass forming chronic pancreatitis was a similar result and was not the one, which excels ERCP in case of qualitative diagnosis. However, we thought that it was not invasively, suitable behind the digestive operation and digestive passage fault, in case of elapse observation and moreover that MRCP is suitable for pick up the pancreatic cancer in our clinic.

Adenocarcinoma↗

PubMed1997

Immunohistochemical studies on glutamatergic, GABAergic and glycinergic axon varicosities presynaptic to parasympathetic preganglionic neurons in the superior salivatory nucleus of the rat.

After the superior salivatory nucleus (SSN) neurons were labeled by administration of cholera toxin B subunit (CTB) or wheat germ agglutinin conjugated horseradish peroxidase (WGA-HRP) to the pterygopalatine ganglion, morphological interactions between SSN neurons and fibers afferent to SSN neurons were examined by light and electron microscopy with double-immunostaining techniques. Antibodies to either the neurotransmitters or its receptor were used to label glutamatergic, GABAergic and glycinergic synapses on these neurons. By light microscopy, SSN neurons were identified in the ipsilateral ventrolateral part of the rostral medulla oblongata, and rich distributions of glutamate- and GABA-immunoreactive (ir) axon varicosities were observed around SSN neurons. Electron microscopy revealed that dendrites of SSN neurons received asymmetric synapses from glutamate-ir axon varicosities. Somata as well as dendrites received symmetric synapses from GABA-ir varicosities, or showed immunoreactivity for glycine receptors. Quantitative analysis by electron microscopy showed that glutamate-ir axon varicosities comprised 45.3% of total axon profiles in the SSN region, while GABA-ir varicosities were 20.8% and varicosities presynaptic to glycine receptors were 19.9%. These findings suggest that glutamatergic, GABAergic and glycinergic inputs, originated from a variety of nuclei, directly affect the activity of SSN neurons, and play a role in the regulation of the pterygopalatine ganglion of the rat.

Animals↗

PubMed1997

Efficacy of a simple left atrial procedure for chronic atrial fibrillation in mitral valve operations.

BACKGROUND: We have devised a simple surgical procedure to be performed on the posterior wall of the left atrium for the treatment of chronic atrial fibrillation (AF) associated with mitral valve disease. The effectiveness of this procedure for serial mitral valve operations was then evaluated. We postulated that chronic AF associated with mitral valve disease could be attributable to a distended left atrium. The refractory period of the distended left atrium was significantly shorter in the left posterior atrial wall, especially at the base of the left atrial appendage and at the orifice of the left posterior pulmonary vein. We hypothesized that the left posterior atrial wall with its shorter fibrillatory cycle length would act as a driver for maintaining the AF, and therefore, surgical ablation of this critical area in the left atrium could terminate the chronic AF. METHODS: The surgical patients were divided into two groups. In group 1 (control group), 15 patients with chronic AF were operated on by the mitral valve procedure only. In group 2, 36 patients underwent this procedure in combination with a concomitant mitral valve operation. The disappearance rate of the AF was estimated by electrocardiography, and atrial function was estimated by transthoracic and transesophageal echocardiography. RESULTS: The chronic AF had been reduced significantly or eliminated at discharge in 4 of 15 patients (26.7%) in the group 1, versus 31 of 36 patients (86%) in group 2 (p < 0.05). In group 2, 29 of the 31 patients (94%) whose AF had disappeared recovered the atrial kick of their right atrium, and 21 patients (22/31; 71%) recovered the atrial kick of their left atrium. CONCLUSIONS: Surgical ablation of the posterior wall of the left atrium was effective in the treatment of chronic AF associated with mitral valve disease. This simple procedure could restore a sinus rhythm and also recovered atrial systolic function. We conclude that the left atrium may act as a driver for sustaining AF in mitral valve disease.

Aged↗

PubMed1997

Right atrial separation for chronic atrial fibrillation with atrial septal defects.

A right atrial separation procedure was performed for the ablation of atrial fibrillation during the concomitant repair of an atrial septal defect. This procedure consisted of a Y-shaped incision in the right atrium, followed by cryoablation of the tricuspid annulus and the atrial septum without any procedures performed on the left atrium. This is a simple and effective method for the elimination of chronic atrial fibrillation associated with atrial septal defects in adults.

Atrial Fibrillation↗

PubMed1997

Right atrial separation procedure for eliminating chronic atrial fibrillation associated with atrial septal defect.

Chronic atrial fibrillation (AF) had been documented in a patient with atrial septal defect for 7 years. A right atrial separation procedure was performed for ablation of chronic AF, concomitant with repair of the atrial septal defect, and followed by atrial electrophysiological mapping. A horizontal transectional incision extending to the borders of the atrial septum and the tricuspid annulus was made. Cryolesions of the atrial isthmus between the margin of the upper incision and the tricuspid valve annulus were created at -60 degrees C for 2 minutes at a time. After the operation, the patient had restored normal sinus rhythm during a subsequent follow-up period of 48 months.

Atrial Fibrillation↗

PubMed1997

Role of the carboxyl-terminal region of Porphyromonas gingivalis fimbrillin in binding to salivary proteins.

Porphyromonas gingivalis fimbriae are considered to play an important role in the adherence and colonization of the bacteria in the oral cavity. In this study, we generated and purified three carboxyl-terminal variants of recombinant fimbrillin (r-FimA 224-337, r-FimA 266-337, and r-FimA 287-337, corresponding to amino acid residues 224 to 337, 266 to 337, and 287 to 337, respectively, of the 43-kDa fimbrillin of P. gingivalis 2561). They were used as inhibitors of P. gingivalis cell binding to human salivary protein-coated hydroxyapatite (HAP) beads. All of the carboxyl-terminal region polypeptides inhibited binding in a dose-dependent manner; however, the inhibitory effect of r-FimA 287-337 was less than that of the other two polypeptides when HAP beads were coated with whole saliva or purified salivary proline-rich protein 1 (PRP1). Assays of binding of a synthetic peptide corresponding to amino acid residues 266 to 286 of P. gingivalis 2561 fimbrillin to salivary proteins showed that this peptide bound strongly to whole saliva or PRP1 but only weakly to statherin. These results suggest that the carboxyl-terminal region corresponding to amino acid residues 266 to 337 of P. gingivalis fimbrillin plays an important role in binding to salivary proteins and that the domain corresponding to amino acids 266 to 286 is likely a major binding site for PRP1s and the domain corresponding to amino acids 287 to 337 is likely a major binding site for statherin.

Adult↗

PubMed1997

Active sites of salivary proline-rich protein for binding to Porphyromonas gingivalis fimbriae.

Porphyromonas gingivalis fimbriae specifically bind salivary acidic proline-rich protein 1 (PRP1) through protein-protein interactions. The binding domains of fimbrillin (a subunit of fimbriae) for PRP1 were analyzed previously (A. Amano, A. Sharma, J.-Y. Lee, H. T. Sojar, P. A. Raj, and R. J. Genco, Infect. Immun. 64:1631-1637, 1996). In this study, we investigated the sites of binding of the PRP1 molecules to the fimbriae. PRP1 (amino acid residues 1 to 150) was proteolysed to three fragments (residues 1 to 74 [fragment 1-74], 75 to 129, and 130 to 150). 125I-labeled fimbriae clearly bound fragments 75-129 and 130-150, immobilized on a polyvinylidene difluoride membrane; both fragments also inhibited whole-cell binding to PRP1-coated hydroxyapatite (HAP) beads by 50 and 83%, respectively. However, the N-terminal fragment failed to show any effect. Analogous peptides corresponding to residues 75 to 89, 90 to 106, 107 to 120, 121 to 129, and 130 to 150 of PRP1 were synthesized. The fimbriae significantly bound peptide 130-150, immobilized on 96-well plates, and the peptide also inhibited binding of 125I-labeled fimbriae to PRP1-coated HAP beads by almost 100%. Peptides 75-89, 90-106, and 121-129, immobilized on plates, showed considerable ability to bind fimbriae. For further analysis of active sites in residues 130 to 150, synthetic peptides corresponding to residues 130 to 137, 138 to 145, and 146 to 150 were prepared. Peptide 138-145 (GRPQGPPQ) inhibited fimbrial binding to PRP1-coated HAP beads by 97%. This amino acid sequence was shared in the alignment of residues 75 to 89, 90 to 106, and 107 to 120. Six synthetic peptides were prepared by serial deletions of individual residues from the N and C termini of peptide GRPQGPPQ. Peptide PQGPPQ was as inhibitory as peptide GRPQGPPQ. Further deletions of the dipeptide Pro-Gln from the N and C termini of peptide PQGPPQ resulted in significant loss of the inhibitory effect. These results strongly suggest that PQGPPQ is the minimal active segment for binding to P. gingivalis fimbriae and that the moiety of the Pro-Gln dipeptide plays a critical role in expressing binding ability.

Bacterial Adhesion↗

PubMed1997

Prophyromonas gingivalis fimbriae mediate coaggregation with Streptococcus oralis through specific domains.

Fimbriae are major adhesive components on the cell surface of Prophyromonas gingivalis. In this study, we evaluated the role of fimbriae in coaggregation with Streptococcus oralis. Fimbriae purified from P. gingivalis competitively inhibited the coaggregation by 100% at a concentration of 50 micrograms/mL. On the other hand, the same amount of lipopolysaccharide isolated from P. gingivalis was inhibited by only 25% of the level of the fimbriae. A fimA-inactivated mutant of P. gingivalis failed to show distinct coaggregation activity. Fimbriae added to a solution of various strains of streptococci caused their self-aggregation at a concentration of 10 to 30 micrograms/mL. The self-aggregation induced by fimbriae was inhibited by lambda-arginine (20 to 40 mM/L). Iodinated fimbriae reacted with S. oralis cells immobilized on the nitrocellulose membrane, and 100 degrees C heating of the cells diminished the binding abilities. Recombinant fimbrillin (r-Fim, corresponding to whole residues 1 to 337 of native fimbrillin) of P. gingivalis also showed 100% inhibition of the coaggregation. The r-Fim variant (residues 1 to 286) lacking the C-terminal 51 residues was as inhibitory as r-Fim. However, the variant (residues 1 to 265) without the C-terminal 72 residues lost 77% of the inhibitory activity. These findings suggested that residues 266 to 286 contain a domain involved in the coaggregation of P. gingivalis with S. oralis. Inhibition by three polypeptides corresponding to residues 266 to 286, 266 to 337, and 287 to 337 was studied. Peptides 266 to 286 and 266 to 337 inhibited by 96 and 100%, respectively, at a concentration of 1.5 nmol/mL. Peptide 287 to 337 also showed a significant inhibitory effect but to a slightly lesser extent than that of peptide 266 to 286. P. gingivalis fimbriae appear to be involved in coaggregation with streptococci, probably through an adhesive protein molecule(s) of the latter, and the fimbriae possess several domains in the C-terminal residues 266 to 337 for interaction with S. oralis.

Bacterial Adhesion↗

PubMed1997

[Interrelations of the calcium concentration in breast milk with maternal intake of cow's milk and milk products, bone resorption and bone mineral density during lactation].

The interrelations of the calcium (Ca) concentration in breast milk with maternal intake of cow's milk and milk products, 24-hour urinary hydroxyproline and Ca concentrations adjusted by creatinine (H.P/Cre, Ca/Cre) and bone mineral density measured by ultrasonic bone densitometry were examined to study the mechanism regulating the calcium concentration in breast milk. Subjects were 105 lactating women, aged 21 to 42 years, at 21.590 days postpartum. 1) The geometric means (logarithmically transformed calculated M +/- SD) of H.P/Cre were 40.7 (31-61) and 36.3 (28-47) mg/g in women lactating less than 150 days and 150 days or more, respectively. These values indicated increased bone resorption. 2) Intake of cow's milk and milk products significantly negatively correlated with urinary H.P/Cre. For women consuming less than 100ml per day of cow's milk, a significant positive correlation was found between the urinary H.P/Cre and Ca concentration in breast milk. These results suggest that the extent of bone resorption depends on maternal Ca intake and the Ca transfer from maternal bone to breast milk in women with a low Ca intake. 3) For women with a cow's milk intake of less than 100ml per day, a significant positive correlation was found between the Ca concentration in breast milk and bone mineral density, indicating that women with bone mineral loss are not able to compensate for the low Ca level in breast milk. 4) Urinary Ca/Cre significantly negatively affected the Ca concentration in breast milk. This result indicates that some amount of Ca in breast milk is due to renal conservation.

Adult↗

PubMed1997

Pyogenic clavicular osteomyelitis associated with disseminated intravascular coagulation and acute renal failure in a patient with non-insulin-dependent diabetes mellitus.

Pyogenic osteomyelitis is often accompanied by diabetes, but the disease in the clavicula has rarely been reported. We describe an unusual case of a 53-year-old man with poorly controlled non-insulin-dependent diabetes mellitus who presented with pyogenic clavicular osteomyelitis and developed DIC and acute renal failure. A 67Ga scintigram revealed an abnormal accumulation of the isotope in the right clavicula, where magnetic resonance imaging (MRI) showed inflammatory changes. This suggests that a 67Ga scintigram and MRI are of clinical value for the early diagnosis of the disease. Antibiotic chemotherapy with gamma-globulin and gebexate mesilate, and hemodialysis almost cured his serious condition.

Acute Kidney Injury↗

PubMed1997

[Ataxic neuropathy in the elderly--clinicopathological study of six cases].

The combination of ataxia with peripheral neuropathy (ataxic neuropathy) is rare. Six elderly patients with peripheral neuropathy who developed ataxia were studied. Of the peripheral neuropathies, ataxic neuropathy was significantly more frequent in patients aged more than 65 years compared with younger patients. Ataxic neuropathy was associated with carcinoma (2 cases), Sjögren's syndrome (1 case), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP, 1 case) and chronic idiopathic ataxic neuropathy (2 cases). The two cases of carcinomatous neuropathy initially showed ataxia, which preceded detection of the carcinomatous lesions in the lung by approximately 1 year. The study cases had many clinical features in common. In the nerve conduction study, sural nerve action potential could not be measured in five of the cases; sural nerve biopsy revealed a decreased density of myelinated fibers in all cases. In particular, the large myelinated fibers were markedly decreased. These findings were common, regardless of the underlying disease, except in the case of CIDP in which there was only a slight decrease in the number of large myelinated fibers. Differential diagnosis based on the clinicopathological features was difficult. Therefore, in cases of ataxic neuropathy, systemic evaluation is necessary to rule out the possibility of carcinoma or various systemic diseases, especially in elderly patients.

Age Factors↗

PubMed1997

Lymphostin (LK6-A), a novel immunosuppressant from Streptomyces sp. KY11783: taxonomy of the producing organism, fermentation, isolation and biological activities.

In the course of screening for inhibitors of the lymphocyte kinase, Lck (p56lck), aiming at novel immunosuppressants, we isolated a novel alkaloid, lymphostin (LK6-A), from the culture broth of Streptomyces sp. KY11783. Lymphostin was produced in a fermentation medium supplemented with a highly porous polymer resin, which prevented the degradation of this compound in the culture broth. Lymphostin inhibited the kinase activity of Lck with an IC50 value of 0.05 microM, and exhibited potent inhibitory activity against the mixed lymphocyte reaction (MLR) with an IC50 value of 0.009 microM.

Chromatography, High Pressure Liquid↗

PubMed1997

Lymphostin (LK6-A), a novel immunosuppressant from Streptomyces sp. KY11783: structural elucidation.

Lymphostin (LK6-A), a novel immunosuppressant, was isolated from the culture broth of Streptomyces sp. KY11783. Lymphostin showed potent inhibitory activity against the lymphocyte kinase, Lck (p56lck). The structure of lymphostin was determined by spectroscopic methods to be a novel tricyclic aromatic alkaloid. A key feature of the structure is the pyrrolo[4,3,2-de]quinoline moiety which is rare among natural products.

Carbon Isotopes↗

PubMed1997

Constitutive mRNA and immunoreactivity for IL-2 in human nasal mucosa.

BACKGROUND: The nasal mucosa is the initial site in the upper airway of host defence against antigenic challenge in the form of airborne allergens, irritants, toxins and infectious agents, and yet little is known about nasal mucosal cytokine expression and function. We hypothesized that IL-2 might play a role in immunocompetence of the upper airway. METHODS: IL-2 immunoreactivity was measured by ELISA in nasal secretions and by Western blot. Immunohistochemistry and electron microscopy were performed on turbinated tissue. mRNA for IL-2 was evaluated by RTPCR and Southern hybridization. RESULTS: IL-2 immunoreactivity was demonstrated by Western blot and quantitated by an enzyme immunoassay. Immunohistochemical and electron microscopy analysis of turbinate tissue revealed interstitial staining for IL-2. By RTPCR, IL-2 message was evident in 5/5 atopics and 5/5 non-atopics. IL-2 message was expressed in all subjects by Southern hybridization to an internal probe after PCR. CONCLUSION: This study has demonstrated constitutive expression of IL-2 protein and mRNA in the upper airway of healthy individuals. The further characterization of cytokines in the upper airway could provide useful insights into immune regulation at the mucosal level.

Base Sequence↗

PubMed1997

[Effects of TNM extension and histopathological type of the tumor on long-term survival rates of parotid and submandibular gland cancer].

The effects of TNM extension and histopathological type of the tumor on 5 and 10-year survival rates were analysed in 1,147 cases of parotid cancer and 271 cases of submandibular gland cancer which had been registered from 152 institutes throughout Japan since 1978. Advance of stage decreased the prognosis significantly, and the decrease was more pronounced in submandibular gland cancer. Facial paralysis also decreased the prognosis of parotid cancer significantly. The prognosis was also affected significantly by the histopathological type of the tumor. The 5-year survival rates of adenocarcinoma, epidermoid carcinoma and undifferentiated carcinoma were only about 30% in parotid cancer and about 20% in submandibular gland cancer. In treatment of salivary gland cancer, the therapeutic approach should be individualized in accordance with the tumor extension and its histopathological type. Improvement of accuracy in preoperative diagnosis of salivary gland cancer is of the utmost importance.

Adenocarcinoma↗

PubMed1997

Nucleotide and amino acid sequence variations in the L1 open reading frame of human papillomavirus type 6.

Human papillomavirus (HPV) type 6 induces benign tumors such as condyloma acuminata and laryngeal papilloma. The HPV-6 DNA has been thought to be a heterogeneous group of subtypes and variant-types. To examine sequence variations of the HPV-6 L1 ORF, we analyzed by single-strand conformation polymorphism (SSCP) and by DNA sequencing 21 specimens from condyloma acuminata and laryngeal papilloma that harbor HPV-6 DNA. PCR products of HPV-6 DNA were digested with 6 restriction enzymes yielding 8 fragments, which were then analyzed by SSCP. The resolution patterns showed that the L1 coding sequences were separated into three SSCP groups, I, II, and III, and two minor groups, (I) and (III). By sequencing the five representatives of each SSCP group and by comparing these sequences with those of HPV-6a [Hofmann et al., 1995] and HPV-6b [Schwarz et al., 1983], we identified base substitutions at 20 positions in the L1 coding region and an amino acid substitution in one case.

Adolescent↗

PubMed1997

[Embolization for massive retroperitoneal hemorrhage from adrenal pheochromocytoma: a case report].

A 68-year-old woman was found crouching in the kitchen with severe upper abdominal pain. She entered a state of shock at our emergency clinic. Abdominal computed tomography (CT) scan demonstrated a 3 cm cystic mass dorsal to the pancreas tail accompanied with a hematoma. On angiography, a bleeding from the left middle adrenal artery was identified and embolized for hemostasis. An operation was performed 3.5 months after embolization. Preoperative evaluation showed the tumor to be endocrinologically inactive. Metoclopramide stimulation test was negative, too. Left adrenalectomy was performed uneventfully without intraoperative increase in blood pressure. However, histopathological diagnosis was pheochromocytoma. Transarterial embolization is an effective treatment for adrenal bleeding. In our case, however, embolization might have caused the tumor to be falsely "endocrinologically inactive".

Adrenal Gland Neoplasms↗