Biomedical subjects

K Hamada

Publications and source records attributed to K Hamada.

At least 289 records · Page 16Linked to original sources

PubMed1995

[A case of sepsis due to Escherichia coli isolated from blood, transtracheal aspiration and urine].

We reported a 53-year-old female who was admitted due to partial loss of consciousness. She had been diagnosed as old pulmonary tuberculosis and diabetes mellitus. She was diagnosed as diabetic keto-acidosis on admission. We isolated Escherichia coli in the blood, transtracheal aspiration (TTA) and from the urine. We have experienced 6 cases where the same bacteria was isolated from the blood and TTA at the same time. In all 6 cases, we have found single bacteria in the blood and a few other bacteria in TTA. Blood culture is the most certain method to detect the origin of infectious diseases. But the compromised host, as in this case, has multifocal infections in many cases. In order to understand the pathological aspects of the infection, we must obtain many kinds of samples and as many as possible.

Blood↗

PubMed1995

[Determination of the neutrophil function in the respiratory infection by chemiluminescence (CL). III: Changes in neutrophil and whole blood CL after chemotherapy against the acute respiratory infection].

We measured the chemiluminescent activity (CL-index) in both the whole blood and isolated neutrophils from 12 patients with acute respiratory infection (7 cases; pneumonia, 4 cases; in the exacerbated phase, chronic lower tract infection, and one; acute bronchitis) two times per each case: before and after chemotherapy. Before the initiation of chemotherapy, neutrophil and whole blood CL was high but whole blood CL was higher. After the completion of chemotherapy, whole blood CL was decreased more significantly than neutrophil CL. There was no correlation between neutrophil CL and whole blood CL. However the neutrophil CL-index.N (neutrophil numbers x neutrophil CL-index) was correlated with the whole blood CL. Thus, we think the number of neutrophils is a critical factor for phagocytic function of neutrophils as determined by CL.

Acute Disease↗

PubMed1995

Erdheim-Chester disease and slowly progressive cerebellar dysfunction.

A 59 year old woman developed pronounced thirst, increased water intake, and increased urinary output followed by slowly progressive cerebellar symptoms. Brain MRI showed abnormal hyperintensity on T2 weighted studies in the region of both dentate nuclei without atrophy of the cerebellum or the brainstem. A 99mTC diphosphonate bone scan showed bone lesions in the distal parts of both femurs as well as distal and proximal parts of both tibias. The diagnosis of Erdheim-Chester disease was made by bone biopsy. This is the first case of Erdheim-Chester disease presenting as a slowly progressive cerebellar syndrome and diabetes insipidus, and also showing high signal lesions in deep cerebellar nuclei on MRI. Skeletal surveys are indicated for patients with otherwise unexplained slowly progressive cerebellar symptoms.

Bone Diseases↗

PubMed1995

Two novel mutations in the coding region for neurophysin-II associated with familial central diabetes insipidus.

Familial central diabetes insipidus is an autosomal dominant disease caused by a deficiency of arginine vasopressin (AVP). We previously reported three distinct mutations in the AVP gene in Japanese familial central diabetes insipidus pedigrees that result in a substitution of Ser for Gly57 in the neurophysin-II (NPII) moiety of the AVP precursor, a substitution of Thr for Ala at the COOH-terminus of the signal peptide, and a deletion of Glu47 in the NPII moiety. In this study, we analyzed the AVP gene in two pedigrees by direct sequencing of the polymerase chain reaction-amplified DNA and found two novel mutations in exon 2, which encodes the central part of the NPII moiety of the precursor. The mutation in one pedigree was a C to A transition at nucleotide position 1891, which replaces Cys67 (TGC) with stop codon (TGA). As the premature termination eliminates part of the COOH domain of the NPII moiety and the glycoprotein moiety, the conformation of the truncated protein is likely to be markedly different from that of normal precursor. In another pedigree, a G to T transversion was detected at nucleotide position 1874, which substitutes polar Trp (TGG) for hydrophobic Gly62 (GGG). It is possible that mutated NPII molecules, as a consequence of a conformational change, cannot bind AVP or self-associate to form higher oligomer complexes. Interestingly, all mutations we have identified to date, with the exception of the signal peptide mutation, are located in exon 2, suggesting the importance of the highly conserved central part of the NPII molecules and/or the NPII moiety in the precursor for AVP synthesis.

Adolescent↗

PubMed1995

Visualization of a single myelination process of an oligodendrocyte in culture by video microscopy.

We described the initial events in the interaction between an oligodendrocyte process and an axon in culture utilizing video time-lapse microscopy. Myelination of an axon by the lamellipodium of an oligodendrocyte was achieved in several steps of cellular process development and coordinated interaction between axon and oligodendrocyte. The initial stage of contact included the formation of a lamellipodium process at the end of an oligodendrocyte process. It appeared that this process contacted the axon several times and was then retracted, and that the filopodia and lamellipodium underwent morphological changes prior to the onset of the myelination. In the second stage, the lamellipodium appeared to thicken and anchor to the axon. Finally, when rippling of the lamellipodial ruffling occurred, the angle between the anchoring filopodium and the axon changed depending on the direction of lamellipodial movement, and the lamellipodium, which was folded in layers, wrapped around the axon like a transverse wave in one motion as observed on the video screen. Thereafter, the lamellipodium assumed a "bursting" form within minutes in real time. This is the first comprehensive overview of how an oligodendrocyte plasma membrane wraps around an axon to form myelin.

Animals↗

PubMed1995

[Diagnostic value of tissue polypeptide antigen in pleural effusions with malignant pleural mesothelioma].

There are no known tumor makers of malignant pleural mesothelioma. We measured the concentration of TPA in the pleural effusions from patients with malignant pleural mesothelioma and from patients with other pleural diseases, evaluate its clinical usefulness. The concentration of TPA was more than 7,000 U/l (mean: 18,600 +/- 9,867 U/l, n = 5) in all patients with malignant pleural mesothelioma, but it was less than 4,000 U/l in those with benign asbestos pleurisy and other benign pleural effusion (benign asbestos pleurisy 1,598 +/- 570, n = 5: p < 0.01, tuberculous pleurisy 1.37 +/- 759, n = 11: p < 0.01, others 2,497 +/- 2,152 n = 3: p < 0.05). The concentration of TPA in the pleural effusions was not significantly different between malignant pleural mesothelioma and lung cancer (12,287 +/- 17,070 U/l). However, in all patients with lung cancer and high TPA concentrations, cytologically malignant cells were detected in the pleural effusions. TPA was high in all five patients with malignant pleural mesothelioma, but cytologically malignant cells were detected in only one patient. Only in malignant pleural mesothelioma (not in other benign disease or in lung cancer) was the concentration of TPA more than 4,000 U/l, and no evidence of malignancy was obtained by cytological methods. These findings suggest that assessing TPA in the pleural effusion might contribute to the diagnosis of malignant pleural mesothelioma.

Adult↗

PubMed1995

[A case of varicella pneumonia in an adult with moss-like substance in the bronchial mucosa].

A 33-year-old man complained of fever, cough and eruptions, and was admitted to our hospital. Chest X-ray films showed diffuse small nodular shadows. A moss-like substance in the bronchial mucosa was seen bronchoscopically. Transbronchial lung biopsy specimen showed infiltration of lymphocytes in the alveolar septa and peribronchiolar area. Transbronchial biopsy specimen of the bronchial lesion showed epithelial hyperplasia and necrosis. Immunohistochemical staining revealed VZV antigen.

Adult↗

PubMed1995

[A case of tuberculosis of the breast--review of the literature published during the last 10 years in Japan].

A 58-year-old woman, not having any history of pulmonary tuberculosis, was admitted to our hospital to examine a tender lump in her right breast. A breast echogram disclosed a well-defined hypoechoic mass lesion, indicating a pyogenic breast abscess. The patient underwent incision, drainage and resection of the tumor under local anesthesia. Histological findings of the resected tumor revealed epitheloid cell granulomas with caseous necrosis in mammary glands, suggesting tuberculosis of the breast. After operation, treatment with isoniazid, rifampisin and ethambutol hydrochloride was begun. After one year, she had complete healing without any indication of recurrence. During the last 10 years, 12 cases of tuberculosis of the breast have been reported. Their ages ranged from 28 to 84 years with an average of 42.8 years. Only one cases had a past history of tuberculosis and in the other cases tuberculosis of the breast was considered to be a primary disease. Axillary lymph-nodes involvement and formation of pyogenic breast abscess occurred in each 7 cases. Acid-fast bacilli were demonstrated in 25% of the reported cases. The histological findings of resected specimens and punch biopsy revealed epitheloid cell granulomas with caseous necrosis in 11 of 12 cases. Seven of 11 cases were treated with combination of surgery and antituberculous chemotherapy.

Biopsy↗

PubMed1995

[A case of desmoplastic malignant mesothelioma].

A 43-year-old man was admitted to Nara Medical University Hospital because of right-sided chest pain. Computed tomographic examination revealed a right pleural effusion and diffuse pleural thickening. Malignant mesothelioma was diagnosed from the results of a percutaneous pleural biopsy, and the patient then underwent right pleuro-pneumonectomy. The resected specimen was examined by light and electron microscopy, which revealed scattered sarcoma-like malignant cells with some epithelial differentiation, in abundant extracellular collagen with storiform derangement. Therefore, desmoplastic malignant mesothelioma (mixed type) was diagnosed. This is a rare histological subgroup of malignant mesotheliomas. The patient died 2 months after the operation, due to multiple and rapidly growing metastases. After lung tissue was dissolved, ferruginous (asbestos) bodies were counted, and the results were consistent with occupational exposure to asbestos (413 asbestos bodies per 5 g of lung tissue).

Adult↗

PubMed1995

Role of histamine H3 receptor on hypoxia-reoxygenation-induced cardiac dysfunction in guinea pigs.

Hypoxia elicited a remarkable decrease in contractility and heart rate in isolated right atria from guinea pigs, a decrease which recovered partially during reoxygenation. Histamine content increased during hypoxia and decreased during reoxygenation. However, hypoxia induced a marked degranulation of mast cells. Pretreatment with alpha-methylhistamine (100-300 nM) recuperated control level contractility and heart rate, and prevented the hypoxia-reoxygenation-induced leakage of creatine phosphokinase (CPK). On the other hand, pretreatment with thioperamide (100-300 nM) decreased contractility and heart rate dose-dependently, and prevented recovery during reoxygenation. These data shows that cardiac histamine may play an important role in the protection against hypoxia-reoxygenation injury through the H3 receptor.

Adenosine Triphosphate↗

PubMed1995

Quantitative autoradiography of alpha 1 adrenoceptors with [3H]tamsulosin in human hypertrophied prostate using computerized image analysis.

Fourteen specimens of human hypertrophied prostate were evaluated for the distribution of alpha 1 adrenoceptors using autoradiography with a computerized image analysis system. The hypertrophied prostatic specimens, obtained at open prostatectomy, were dissected vertically to the urethra, and sectioned at 10 microns. They were immersed in 1 nM of specific alpha 1 ligand, [3H]tamsulosin chloride ([3H]tamsulosin) and exposed to autoradiographic film. The images were analysed by a computerized image analysis system. The total binding of [3H]tamsulosin in the whole section (n = 14) was 0.82 +/- 0.21 (mean +/- SE) nCi mg-1. The autographic data were correlated with data obtained in a membrane-binding assay. The prostatic tissue studied was divided into urethral, glandular and stromal zones, the latter two zones being further divided into the inner and outer areas. The total binding of [3H]tamsulosin in the urethral zone (n = 7) was 0.65 +/- 0.32 nCi mg-1. The glandular zone contained significantly more abundant alpha 1 adrenoceptors than the stromal zone and their densities (glandular vs stromal) were 1.15 +/- 0.19 nCi mg-1 (n = 14) vs 0.72 +/- 0.15 nCi mg-1 (n = 14), respectively (p < 0.05). The data from the whole section were not affected by prostatic weight. This method described enabled the distribution of the receptors in different sites to be evaluated both morphologically and quantitatively.

Adrenergic alpha-Antagonists↗

PubMed1994

Biphasic and differential expression of cytosolic glutamine synthetase genes of radish during seed germination and senescence of cotyledons.

Three structurally distinct cDNA clones for cytosolic glutamine synthetase (GS1) were isolated from libraries prepared from senescing radish cotyledons. Northern blot analysis showed that transcripts from two of the three genes encoding GS1, Gln1;1 and Gln1;3, accumulated in the cotyledons during both dark-induced and natural senescence. Transcripts from the last gene, Gln1;2, remained at a low level during both processes. Transcripts from all three Gln1 genes accumulated in cotyledons of germinating seeds. We infer from these findings that GS1 enzymes function in both germination and senescence to convert ammonium to glutamine to remobilize nitrogen from source to sink organs. We have also examined the pattern of expression of these genes in different tissues. All three genes are expressed in roots. A large amount of transcripts from Gln1;1 accumulated in hypocotyls. Whereas none were transcribed in flowers. During dark-induced senescence of cotyledons, application of inorganic nitrogen delayed chlorophyll degradation. Inorganic nitrogen enhanced the accumulation of Gln1;1 transcripts, but decreased those of Gln1;3. In contrast, application of glutamine promoted yellowing of cotyledons during the dark treatment, and slightly increased the amounts of transcripts from Gln1;3 but decreased those of Gln1;1. Transcription of the three Gln1 genes appears, therefore, to be differentially regulated in radish cotyledons during senescence and germination.

Amino Acid Sequence↗

PubMed1994

How do oligodendrocytes ensheath and myelinate nerve fibers?

Oligodendrocyte precursor cells were cultured from newborn rat brain and studied their differentiation and proliferation. They have identified type-1, type-2, and type-3 oligodendrocytes based on the expression of characteristic marker molecules that frequently used to stage oligodendrocyte development. The type-3 oligodendrocytes were observed to send but tentative that locate axons prior to myelination. These processes terminate in lamellipodia, which eventually enwrap the axon and begin the myelination process with several steps. At the first stage, ruffling is immediately induced at the lamellipodia with filopodia made of oligodendrocyte processes, and the axon is contacted several times; then process retraction occurs to reform the filopodial and lamellipodial parts prior to the onset of the myelination. Second, after filopodial movements and lamellipodial ruffling occur again, their morphology is dramatically changed to become three thick filopodia that anchor to the axon. Finally, lamellipodial ruffling parts ripple, the angle between the position of the resting filopodium and the axon change, depending on the start of axonal movement, and the lamellipodia turn around the axon like a transverse wave with one stroke of the brush, as observed on the video screen, and their rolling membrane changes to the bursting form within minutes in real time.

Animals↗

PubMed1994

Effect of anti-inflammatory agent etodolac on antigen-induced contractions of the trachea and lung parenchyma of guinea pigs.

Etodolac, which inhibits the activity of cyclooxygenase, did not affect antigen-induced contractions of the trachea and lung parenchyma of guinea pigs. Indomethacin tended to enhance antigen-induced contractions of the trachea and significantly enhanced contractions of the lung parenchyma. The inhibitory activity of AA-861, a 5-lipoxygenase inhibitor, in antigen-induced contractions of the trachea and lung parenchyma was more potent than that of ozagrel, a thromboxane A2 (TXA2) inhibitor. Thus, lipoxygenase products played a more important role than TXA2 in antigen-induced contractions of the trachea and lung parenchyma. These results suggest that the enhancement of antigen-induced contractions by indomethacin might be due to an increase in anaphylactic release of lipoxygenase products through the inhibition of cyclooxygenase. Since etodolac did not enhance antigen-induced contractions, we attempted to determine whether or not etodolac inhibits 5-lipoxygenase. Etodolac was found to have no effect on 5-lipoxygenase activity. Therefore, the low adverse effect of etodolac on antigen-induced contractions of the airway may be due to its weak inhibition of cyclooxygenase in the airway. These results suggest that etodolac would have only a very slight, if any, adverse effect on the airway in patients with asthma.

Animals↗

PubMed1994

Physiological expression of the 2',5'-oligoadenylate synthetase gene in mouse intestine.

2',5'-Oligoadenylate synthetase (2-5A synthetase) is an enzyme induced by interferon (IFN) that is considered to play an important role in IFN action. The normal mouse, not treated exogenously with any IFN or IFN inducers, has been shown to have an enhanced level of 2-5A synthetase activity, which is distributed among several lymphoid tissues. In the present report, we investigated the expression of the 42-kD 2-5A synthetase mRNA in the organs of normal mice using RNA blot hybridization and reverse transcriptase polymerase chain reaction (RT-PCR). Among the organs tested, intestinal tissues had the highest levels of this mRNA. Furthermore, the 42-kD 2-5A synthetase mRNA was expressed in intestines from germ-free mice and fetuses. Immunoblotting analysis using a monoclonal antibody against the 42-kD 2-5A synthetase revealed that the 42-kD enzyme as well as a cross-reactive protein of 30 kD were produced in the organs of the normal mouse.

2',5'-Oligoadenylate Synthetase↗

PubMed1994

Mucosa-specific DNA adducts in human small intestine: a comparison with the colon.

The presence of several covalent DNA adducts in the human colon was demonstrated by 32P-postlabeling in a previous study. We demonstrated that DNA of all the colonic mucosa tested were selectively adducted by a single genotoxic agent and this modification was completely absent in the DNA of muscular layers. In this study, the DNA adducts of the small intestine are compared with those of the colon to understand the role of mucosa-specific DNA adduct (MSA) in intestinal carcinogenesis. The mucosal DNA of the small intestine from 19 adults undergoing surgery due to gastric carcinoma (seven cases), pancreatic carcinoma (four cases), colon carcinoma (four cases), small intestinal tumor (two cases), intestinal trauma (one case) and ectopic pancreas (one cases) were analyzed. The mucosa-adjacent muscular layer DNA of the corresponding samples was examined as a control. Several common DNA adducts were observed in both mucosal and muscular layers of all the adults. Besides these common background DNA adducts, two MSAs (Si1, Si2) were detected in most of the adults as in colon cases. Si1 was present in all adults examined (19/19 cases) at a level of 0.04-0.22 adducts/10(8) nucleotides (average 0.09) and Si2 was found in 13/19 patients at a level of 0.03-0.08 adducts/10(8) nucleotides (average 0.05). Si2 was the same adduct detected in the adult colonic mucosa. However, they were absent in the adjacent muscular layer as well as in the neonatal intestine tested as a control. The total level of the mucosa-specific DNA adducts of the small intestine was approximately 28-fold lower than that of the colon. Considering that the incidence of cancer in the small intestine is rather lower than that in the colon, these results may be relevant to the development of human intestinal cancer.

Aged↗

PubMed1994

Presence of mucosa-specific DNA adduct in human colon: possible implication for colorectal cancer.

DNA of normal mucosa and the adjacent muscular layer from 18 adults suffering from colorectal neoplasms was examined by 32P-post-labeling analysis in order to estimate the exposure of the human colon and rectum to environmental carcinogens. Colorectal DNA samples obtained from six newborns were also examined as a normal control because they were presumed to have been minimally exposed to environmental carcinogens. One common mucosa-specific DNA adduct was found in the normal colorectal wall in all adults at the level of 0.10-34.13 adducts/10(8) nucleotides (mean +/- SD: 3.64 +/- 7.92 adducts/10(8) nucleotides), however, these were absent from the newborns' colons. Although several common spots were present in the mucosa, muscular layer and newborn tissues, there was no muscular layer-specific DNA adduct. The relationship between the levels of the mucosa-specific DNA adduct in the non-cancerous part and the histological degree of malignancy was not significant. The presence of this mucosa-specific DNA adduct in adult colon suggests that the human colon is commonly exposed mainly to one environmental carcinogen. This carcinogen is supposed to originate from foods, because the incidence of colorectal carcinoma is closely linked to dietary habits and the mucosa-specific DNA adduct was not present in newborns who had never ingested food. The incidence of adult colonic cancer originating from its mucosa is high, while cases of muscular origin or in newborn colon are rare. Therefore, the mucosa-specific DNA adduct is presumably responsible for the development of colonic cancer of epithelial origin.

Adenocarcinoma↗

PubMed1994

In vitro formation of DNA adducts with bile acids.

The in vitro experiment was carried out following 32P-postlabeling analysis to determine the DNA-reactive bile acids present in the human body. The unconjugated and conjugated forms of cholic (CA), chenodeoxycholic (CDCA), deoxycholic (DCA) and lithocholic acid (LCA) were added to calf thymus DNA followed by 1 h of incubation at 37 degrees C. After the incubation the mixture was analyzed by the nuclease P1 modification of 32P-postlabeling. Among the 12 bile acids tested, our results showed that unconjugated CDCA and LCA and the glycine and taurine conjugates of LCA (g-LCA, t-LCA) were able to bind covalently with naked DNA in vitro without intervention of any catalyst. It was also shown that bile acid alone did not give any spot on TLC. These binding reactions depended on the bile acid concentration in a linear manner. The data on the extent of binding at a concentration of 0.1 mg/ml showed values of 28.5 (t-LCA), 23.7 (g-LCA), 3.47 (LCA) and 1.32 (CDCA) adducts per 10(8) nucleotides. These reactive bile acids were also incubated with COLO 205 human colon carcinoma cells and Hep G2 human hepatocellular carcinoma cells for 24 h, but no specific DNA adduct was formed. Further, when LCA or CDCA was administered into male Fischer 344 rats by gavage at a dose of 10 mg/rat every 8 h for 3 days, no specific DNA adduct was detected in their liver or colon. Covalent DNA adducts are believed to cause alteration of the primary structure of genes, which is potentially linked to carcinogenesis. Though our preliminary data failed to detect any bile acid-related DNA adducts in the cultured cells or in rats, the results may provide a basis for assuming some of these bile acids to be potential initiators of colon cancer.

Animals↗