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Biomedical subjects

M Hayakawa

Publications and source records attributed to M Hayakawa.

At least 163 records · Page 9Linked to original sources

Inhibition of a Porphyromonas gingivalis colonizing factor between Actinomyces viscosus ATCC 19246 by monoclonal antibodies against recombinant 40-kDa outer-membrane protein.

1. Porphyromonas gingivalis, an important pathogen in human periodontal disease, aggregates with Actinomyces viscosus ATCC 19246. 2. Monoclonal antibodies (mAbs) against purified recombinant 40-kDa outer-membrane protein (r40-kDa, OMP) of P. gingivalis 381 inhibited its coaggregation with A. viscosus ATCC 19246 in a dose-dependent manner. 3. Five mAb clones against r40-kDa OMP were selected. The isotype of the five was IgG1. 4. Pg-ompA2 inhibited the coaggregation of several strains of P. gingivalis with A. viscosus ATCC 19246 cells.

Actinomyces viscosus↗

Genes of human ATP synthase: their roles in physiology and aging.

The reaction of ATP synthase (F0F1) is the final step in oxidative phosphorylation (OXPHOS). Although OXPHOS has been studied extensively in bacteria, no tissue-specific functions nor bioenergetic disease, such as mitochondrial encephalomyopathy and aging occur in these organisms. Recent developments of the Human Genome Project will become an important factor in the study of mammalian bioenergetics. To elucidate the physiological roles of human F0F1, genes encoding the subunits of F0F1 were sequenced, and their expression in human cells was analyzed. The following results were obtained: A. The roles of the residues in F0F1 are not only to transform the energy of the electrochemical potential (delta mu H+) across the membrane, but also to respond rapidly to the changes in the energy demand by regulating the intramolecular rotation of F0F1 with the delta mu H+ and the inhibitors of the ATPase. B. The roles of the control regions of the F0F1 genes, are to coordinate both mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) depending on the energy demand of the cells, especially in muscle, C. The cause of the age-dependent decline of ATP synthesis has been attributed to the accumulation of mutations in mtDNA. However, the involvement of nDNA in the decline is also important because of telomere shortening in somatic cells, and age-dependent mtDNA expression analyzed with rho degree cells (cells without mtDNA).

Aging↗

New 3-dimensional mapping device for cystoscopy.

PURPOSE: The crucial shortcoming of cystoscopy is that it does not measure the size of observed objects, and so we developed a new device that adds measurement capability to the cystoscope. MATERIALS AND METHODS: The device consists of 5 arms linked to each other by freely bending joints. Before use 1 end of the arm is fixed to the examination table and the other end is linked to the eyepiece of the cystoscope. While linked to the arms, the cystoscope can move freely in any direction. Each joint carries an accurate sensor to measure its angle. The angle measurements are calculated collectively to obtain the 3-dimensional coordinates at the tip of the cystoscope. The tip of the cystoscope can be moved to the other side of the objects to be measured, which provides a pair of 3-dimensional coordinates, because the distance between them can be calculated. RESULTS: We could calculate the distance between the bladder neck and each ureteral orifice, and the angle of the bladder neck formed with the left and right orifices in clinical cases. By continuous measurement of the location of the bladder neck and the ureteral orifice, it was clearly demonstrated that the distance between them increased as the bladder filled. CONCLUSIONS: Our computer assisted, 3-dimensional mapping device can replace unreliable cystoscopic assessment with more reliable numerical values. New diagnostic criteria based on the exact numerical values can be established with the use of this device.

Cystoscopes↗

A new genus of the order Actinomycetales, Spirilliplanes gen. nov., with description of Spirilliplanes yamanashiensis sp. nov.

Actinomycete strain YU127-1T (T = type strain), which produces zoospores, was isolated from a soil sample. The aerial mycelium of this organism at maturity forms short chains of spores. The hyphae form coils, and sporangia are not observed. Strain YU127-1T contains glutamic acid, glucosamine, glycine, alanine, and meso-diaminopimelic acid in its cell wall (wall chemotype II), 3-O-methylmannose, mannose, xylose, and glucose as whole-cell sugars, meanaquinone 10(H4), and glycolyl cell wall polysaccharides and has a guanine-plus-cytosine content of 69.0 mol%. Mycolic acids are absent. Phosphatidylinositol and phosphatidylethanolamine are diagnostic phospholipids. The chemotaxonomic data, except for the lack of arabinose in the whole-cell sugars, indicate that this strain belongs to the family Micromonosporaceae. The morphological and physiological characteristics and chemotaxonomic and phylogenetic data for this strain differ from those of the previously described actinomycetes. We therefore propose a new genus, spirilliplanes, for this organism; the type species of the genus is Spirilliplanes yamanashiensis sp. nov., and the type strain of S. yamanashiensis is strain YU127-1 (= IFO 15828).

Actinomyces↗

[Urinary neopterin levels in patients with genitourinary tract malignancies].

BACKGROUND: Neopterin is released from macrophages upon stimulation with gamma-interferon, secreted by activated T cell. Therefore it has been recognized as a useful indicator of the activation of the T cell-macrophage system. Increased neopterin levels are observed in patients with acute graft rejections, viral infections, auto-immune diseases and several malignancies. Urinary neopterin concentrations were determined in patients with genitourinary tract malignancies to evaluate the usefulness of neopterin as a tumor marker. METHODS: Urinary neopterin concentrations were determined by high-performance liquid chromatography in 90 patients with genitourinary tract malignancies and 28 patients with benign urological tumors and 34 healthy subjects. RESULTS: Increased urinary neopterin levels were observed in 52% of the patients with genitourinary tract malignancies and 7% with benign urological tumors. The positivity rate in patients with renal cell carcinoma (RCC), renal pelvic and ureteral tumor, bladder tumor (BT), prostatic carcinoma (PC) and testicular tumor was 68%, 80%, 47% and 30%, respectively. The difference in the urinary neopterin levels between low and high stages was highly significant (p < 0.0005) in patients with RCC (stage I-II vs. stage III-IV) and BT (T1S-1 VS. T2-4). The urinary neopterin levels were also correlated with the tumor grade in patients with RCC and PC. CONCLUSION: Our study suggests that urinary neopterin levels may supplement laboratory examinations for patients with genitourinary tract malignancies, providing useful information in evaluating the tumor stage and follow-up of the disease.

Adult↗

[Prognosis of renal cell carcinoma coexisting with renal cystic diseases--results of nation-wide survey in Japan].

OBJECTIVE: To study the outcome of the patients with renal cell carcinoma (RCC) coexisting with renal cystic disease. SUBJECTS AND METHODS: The nation-wide survey conducted in 1989 enrolled 223 patients with RCC coexisting with renal cystic disease. Of those 223, we could follow up 216 patients in the second survey in 1994. RESULTS: Renal cystic diseases coexisting with RCC included simple renal cysts in 69 cases, acquired cystic disease of the kidney (ACDK) in 61, cystic RCC in 54, multilocular renal cysts in 19, polycystic kidney in 3, miscellaneous cysts in 9, and unspecified cyst in 1. The overall 5-year survival was 84%. The mean survival of the patients without any symptoms was significantly higher than that of those with symptoms. The survival of those with ACDK was lowest, and that will cystic RCC was highest. The survival was significantly different between the two groups, however the disease specific survival excluding the effect of dialysis was not significantly different between the two groups. Regarding TNM category, those with pT1 or pT2, comprising 87% of the subjects, carried a prognosis more favorable than those with pT3 or pT4. Among those undergoing cyst puncture (47 patients), positive cytology resulted in poorer prognosis. However, there was no such difference in the prognosis between punctured group and non-punctured group. CONCLUSION: Those with RCC coexisting with renal cystic disease carried a favorable prognosis. Cyst puncture were not concluded to exert an unfavorable effect on the prognosis at least in this study.

Adult↗

[Diagnostic imaging of renal pedicle injury].

We reviewed the radiological findings of 8 patients with renal pedicle injury admitted to our emergency center from January 1986 through September 1995 and compared them with the previously reported findings. The patients included 3 with renal artery occlusion and 5 with avulsion or disruption of renal pedicle vasculature. Extended retroperitoneal hematoma such as contralateral pararenal or central parahilar hematoma was visualized in all 5 cases with avulsion or disruption of renal pedicle vasculature. Although lack of contrast enhancement of injured renal parenchyma is a hall-mark of renal pedicle injury, three cases did not demonstrate this typical finding. In these three cases, one showed partial and the others showed total enhancement of the injured renal parenchyma on contrast enhanced CT. Partial enhancement in one case was found to represent total occlusion of the main renal artery and an intact accessory polar branch on angiography. The other two cases showed total enhancement of the renal parenchyma, with renal vein perforation done and complete disruption of the main renal artery and vein in the other. The latter findings were thought to be due to the maintenance of vascular flow surrounded by hematoma. In conclusion, when central parahilar hematoma is identified, the possibility of renal pedicle injury should be considered even if the renal parenchyma is well enhanced.

Adolescent↗

Pitfalls in aneurysm surgery in acute stages.

Since the dawn of aneurysm surgery, many aneurysms present a more complex challenge. Large size, intimacy with critical perforator branches, deep location, atherosclerotic walls, ruptured aneurysms in the elderly and incorporation of afferent or efferent arteries in the dome represent factors that singly or in combination preclude safe clipping while high pressure circulation continues in the aneurysm. Despite the relative frequency of many class of aneurysms, there remains in the neurosurgical community some degree of confusion regarding the detailed anatomic features and the technical aspects of the treatment of these lesions in the acute stage. In our study of 1,433 cases, we have enumerated four aspects of the pitfalls in aneurysm surgery which should be considered when planning the operative approach to these lesions. These four aspects will be reviewed in relation to the aneurysm surgery: (1) inadequate pre-operative planning; (2) inappropriate response to unexpected premature rupture; (3) poor clipping techniques and clip selection; (4) unintentional occlusion or injury of perforating branches. This discussion will simply elaborate our own conceptual and microsurgical technical approach in dissecting the aneurysms. Minimal retraction was used during the whole surgical procedure. The intracranial brain tension was reduced through a ventricular tap for hydrocephalus or evacuation of hematoma prior to aneurysm surgery. A venous pathway was established for blood circulation. Sharp dissection, using our newly designed jet irrigation bipolar suction method was employed. Regarding the clipping of the aneurysm, we used the tentative clipping and the dome coagulation method thereby preventing the ischemic changes and shortening of the entire clipping procedure. Although the strategies, discussed represent simply our approach to this problem, the principles included have proven quite successful and have allowed safe and definitive treatment in the overwhelming majority of patients and also options to overcome the pitfalls in aneurysm surgery.

Acute Disease↗

[(Neurological CPC-59). A 65-year-old man with a history of gastric cancer who presented progressive loss of vision, memory loss and consciousness disturbance].

We report a 65-year-old man with progressive loss of vision and consciousness disturbance. The patient was well until his age of 63 when he was found to have a gastric cancer. He was treated by the tumor resection and chemotherapy; he was apparently well, but hepatic metastases were found in the next year (1996). In June, 1996, he noted an onset of blurred vision more on the left. He was admitted to the ophthalmology service of our hospital on July 14, 1996. His vision was 0.8 on the right and 0.15 on the left. He was treated with oral prednisolone with slight improvement. He was also found to have IgM kappa-type monoclonal gammopathy; Bence-Jones protein was positive and a bone marrow aspiration revealed that approximately 10% of bone marrow cells were atypical plasma cells. His vision had progressively got worse and he became blind by the end of October 1996. A chest X-ray and cranial CT scan revealed multiple abnormal nodular densities. In the middle of November 1996, he became confused, disoriented and agitated. His mental symptoms had progressively became worse, and a neurologic consultation was asked on December 10, 1996. Neurologic examination revealed that he was somnolent with decreased attention to his surroundings. He showed marked disorientation and memory loss. Higher cerebral functions appeared intact. He was able to recognize only light and dark. Pupils were moderately dilated with very sluggish light reflex remained. Vertical gaze was moderately restricted and horizontal nystagmus was noted upon left and right lateral gaze. The remaining of the neurologic examination were unremarkable. General physical examination revealed hepatosplenomegaly; the liver was palpable by 3 cm below the right costal margin. Laboratory examination revealed anemia (Hb10.1 g/dl) and thrombocytopenia (43,000/microliter). A cranial CT scan and MRI revealed a mass lesion in involving the chiasmatic and bilateral hypothalamic areas. The tumor showed intense homogeneous enhancement after Gd-DTPA infusion. The patient was treated with dexamethasone and radiation. After 9 Gray radiation, he showed deterioration in the sensorium; a cranial CT scan revealed a hydrocephalus of the right ventricle with the midline shift towards left. The radiation was discontinued. The subsequent clinical course was complicated by aspiration pneumonia and thrombocytopenia. He expired on January 4, 1997. The patient was discussed in a neurological CPC and the chief discussant arrived at the conclusion that the patient had systemic malignant lymphoma with metastasis to the brain judging from the characteristics of MRI and CT findings. Opinions were divided between malignant lymphoma and metastatic brain tumor. Post-mortem examination revealed plasmacytoid lymphocytic infiltration in the bone marrow. Immunologically, these cells were positive for IgM and kappa-type light chain. These plasmacytic infiltrations were seen in the lungs and lymph nodes. These findings were consistent with the diagnosis of Waldenström's macroglobulinemia. In the liver metastatic cancer tissues were seen; microscopic pictures were essentially similar to those of resected gastric cancer. No local recidive was noted in the stomach. In the central nervous system, a necrotic tissue was involving the hypothalamic area bilaterally; no clear neoplastic cells were found, however, lymphocytic and plasmacytic infiltrations were seen in the perivascular space. In the optic nerves, loss of myelin and axons were seen. These findings most likely mass formation from macroglobulinemia which underwent necrotic change after radiation. Mass formation in the brain is rare for Waldenström's macroglobulinemia, although it has been reported. The relation between gastric cancer and macroglobulinemia in this patient is unclear.

Adenocarcinoma↗

Three-dimensional reconstruction of intravascular ultrasound images of coronary stents using an ECG-gated pull-back device.

Three-dimensional reconstruction (3D-R) of intravascular ultrasound (IVUS) images is not yet satisfactory because of artifacts caused by cardiac movement. This problem can be overcome with a new device, an electrocardiographic (ECG)-gated pull-back system. Using this device a catheter is pulled back stepwise gated by the ECG, and IVUS dynamic images of an entire cardiac cycle are acquired at each step. We performed 3D-R of IVUS images of stents using this new device in six patients with Palmaz-Schatz coronary stent implantation. We obtained precise 3D images in all cases, and stent structure was visualized in detail. In conclusion, use of an ECG-gated pull-back device enables precise 3D-R of IVUS images and provides useful information on the coronary artery.

Aged↗

Molecular cloning and characterization of the gene encoding 53 kD outer membrane protein of Porphyromonas gingivalis.

The pga53 gene which encoded the antigenic 53 kD outer membrane protein (Ag53) was isolated from a genomic DNA library of Porphyromonas gingivalis FDC381 by using an Ag53-immunized rabbit serum. Determination of its complete nucleotide sequence revealed that the precursor of Ag53 had a 50 amino-acid putative signal sequence and the mature protein of 448 amino acids. The deduced amino acid sequence after a 50 amino-acid putative signal sequence was in complete agreement with the first 20 N-terminal amino acids of purified Ag53. Analysis of the deduced amino acid sequence revealed the presence of a highly hydrophilic proline-rich region at the C-terminal of Ag53. The deduced amino acid sequence showed 29.9% homology with that of a 72 kD cell-surface protein in P. gingivalis. Southern hybridization revealed that pga53 was specific to several P. gingivalis strains and that P. gingivalis strains which did not possess Ag53 had genes homologous to pga53.

Amino Acid Sequence↗

Age-related extensive fragmentation of mitochondrial DNA into minicircles.

In normal human hearts, a progressive age-related fragmentation of mitochondrial (mt) DNA into various-sized deleted (delta) mtDNA up to 358 types was documented by a novel total-detection system for deletions. The delta mtDNA lacking replication origin(s), minicircles, accumulated up to 280 types out of the 358, suggesting a yet unknown replication mechanism in human. Wild-type mtDNA decreased linearly down to 11% of the total with age negatively correlated with delta mtDNA and oxidized nucleoside, 8-hydroxydeoxyguanosine. A remarkable mirror image observed in delta mtDNA size distribution as well implies that random hydroxyl-radical attacks resulted in double-strand break and rejoining of mtDNA as a preferable mechanism to form various delta mtDNA of closed circular duplex. These facts support the 'redox mechanism of aging.'

Adolescent↗

Accumulation of deletions and point mutations in mitochondrial genome in degenerative diseases.

Accumulation of various mutations in the mitochondrial genome is proposed as an important contributor to aging and degenerative diseases. Extensive fragmentation of mtDNA was detected in association with increased 8-hydroxydeoxyguanosine content in the heart mitochondrial DNA (mtDNA) from a patient with premature aging and mitochondrial cardiomyopathy, who carried a mutation within the mitochondrial tRNA(Asp) gene. This result suggests that damage to mtDNA by hydroxyl radical and accumulation of deleted mtDNA can be accelerated by a specific mitochondrial genotype. Similarly, extensive fragmentation of mtDNA was also detected in cultured cells exposed to a high oxygen concentration atmosphere, implying that mtDNA is vulnerable to reactive oxygen species. To clarify the role of point mutations accumulated in mtDNA, we examined the sequence heterogeneity of mtDNA in the skeletal muscle of a MELAS patient who carried a mutation within the mitochondrial tRNA(leu)(UUR) gene. The analysis revealed that the frequency of mutant clones in the MELAS muscle was significantly higher than those in an age-matched control muscle and a control placenta. Some of these nucleotide substitutions were missense and nonsense mutations, which potentially have deleterious effects on the mitochondrial function. The frequency of nucleotide substitutions in the striatum of three patients with Parkinson's disease was also significantly higher than that in control tissues. We also observed increased protein modification by 4-hydroxy-2-nonenal, a lipid peroxidation by-product, in Parkinson's disease. These results suggests that a vicious cycle contributes to the progression of degenerative process. In this cycle, first a primary mitochondrial mutation(s) induces a mitochondrial respiratory defect, which increases the leakage of reactive oxygen species (ROS) from the respiratory chain. Then the ROS would trigger accumulation of secondary mtDNA mutations in postmitotic cells, leading to further aggravation of mitochondrial respiratory defects and increased production of ROS and lipid peroxides from mitochondria, and thus resulting in degeneration of cellular components.

Aged↗