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Biomedical subjects

S Kawamoto

Publications and source records attributed to S Kawamoto.

At least 127 records · Page 7Linked to original sources
PubMed1998

Isolation of genes identified in mouse renal proximal tubule by comparing different gene expression profiles.

An expression profile is a list based on a large scale sequencing of 1000 cDNA clones, showing the expressed genes and the abundance of their transcripts in a given cell or tissue (Okubo K et al: Nature Genet 2:173, 1992). We constructed an expression profile of mouse renal proximal tubules (PT) carefully isolated by microdissection in order to characterize its gene expression. Altogether 1000 clones were analyzed; there were 646 types of transcripts in PT, among which 196 were identical or homologous to the previously reported genes. The most abundant transcript was kidney-androgen regulated protein. By comparing the expression profile of PT with those obtained from other sources, several genes were identified only in PT. They included known transcripts and transcripts that were not homologous to the known genes. Three (GS4001, 3991, and 4059) of the non-homologous genes were analyzed by Northern blotting and in situ hybridization, and GS4001 and 4059 were predominantly expressed in the kidney, whereas GS3991 was detected in the liver as well as in the kidney. The sequence analysis of the full-size cDNAs demonstrated that GS4001 was a new member of aspartic proteinases and GS4059 was a novel gene. It also revealed that GS3991 was a mouse homologue of SA gene known to be expressed in PT. The expression profile of mouse PT and its comparison with those of other tissues and cells provide an alternate way of isolating genes predominantly expressed in PT, and also provides probes to study the molecular mechanisms of gene expression in the kidney.

3T3 Cells↗
PubMed1998

Long-range effect of mutation of calcium binding aspartates [correction of asparates] on the catalytic activity of alkaline protease from Pseudomonas aeruginosa.

Apart from a catalytic domain, the alkaline protease of Pseudomonas aeruginosa has a novel parallel beta-helix domain stabilized through Ca2+ binding. In order to clarify the importance of the beta-helix structure in maturation of the enzyme, aspartic residue D-356 or D-365 in the Ca2+ binding sequence motif was replaced with L-alanine, and the catalytic activity of each mutant was assayed. These mutants did not show any proteolytic activity, although the composition of their polypeptide chains was the same as that of the wild type except for the mutated alanine residue. These results suggest that D-356 and D-365 are important in control of the beta-helix folding induced by Ca2+ binding and that incomplete beta-helix folding due to the lack of their side-chains affects the maturation of the enzyme in the long-range order.

Aspartic Acid↗
PubMed1998

High serum levels of somatomedin-C and diabetes mellitus caused by obstructive hydrocephalus: case report.

OBJECTIVE AND IMPORTANCE: This case demonstrates a relationship between hydrocephalus with a huge diverticulum of the third ventricle and high serum levels of somatomedin-C. Somatomedin-C levels become high when the secretion of growth hormone from the adenohypophysis increases, and previous reports state that hydrocephalus decreases the secretion of growth hormone. CLINICAL PRESENTATION: The patient suffered from diabetes mellitus and obesity, and serum somatomedin-C levels were high. A pituitary adenoma or ectopic growth hormone-producing tumor was suspected. Magnetic resonance imaging did not reveal either of these abnormalities but indicated hydrocephalus with a diverticulum of the third ventricle. INTERVENTION: After ventriculoperitoneal shunt placement, the blood glucose and serum somatomedin-C levels of the patient decreased toward normal. Six months later, the shunt tube became obstructed and serum somatomedin levels increased. The levels decreased again after shunt revision. CONCLUSION: To our knowledge, this is the first published report of obstructive hydrocephalus with a diverticulum of the third ventricle compressing the hypothalamus and increasing the serum levels of somatomedin-C.

Adenoma↗
PubMed1998

Comparative ribosomal protein (L11 and L30) sequence analyses of several Streptomyces spp. commonly used in genetic studies.

The taxonomic relationships among nine strains of Streptomyces, which have been commonly used for genetic studies, were examined by sequence analysis of their ribosomal L11(= rplK) protein genes. Phylogenetic relationships among these organisms derived from similarity sequence analysis of the rplK genes were in good agreement with those derived from the analysis of the deduced L11 protein amino acid sequence itself, indicating complete sequence homology among Streptomyces coelicolor A3(2), 'Streptomyces lividans 66' and Streptomyces violaceoruber JCM 4423. S. coelicolor A3(2) related (in the order of closer relatedness) to Streptomyces antibioticus ATCC 14888, Streptomyces griseus IFO 13189, Streptomyces lavendulae MA 406 A-1 and Streptomyces virginiae MAFF 6014. Sequence analysis of the 26 N-terminal amino acid residues of ribosomal L30 proteins also resulted in similar phylogenetic relationships, except that S. griseus, S. lavendulae and S. virginiae were not differentiated from each other using this method. These findings concerning the phylogenetic relationship therefore confirm the previous conclusion that S. coelicolor A3(2), 'S. lividans 66' and S. violaceoruber should be recognized as a single taxon at the species level.

Amino Acid Sequence↗
PubMed1998

Differential gene expression of TGF-beta isoforms and TGF-beta receptors during the first trimester of pregnancy at the human maternal-fetal interface.

PROBLEM: The transforming growth factor (TGF)-beta s are multifunctional cytokines, and they play a role in the controlled growth of trophoblasts. Moreover they are thought to be important in maternal-fetal interaction during early gestation. METHOD OF STUDY: Human decidual and villous tissues in the first trimester were Northern blotted and amplified by reverse transcription-polymerase chain reaction to measure the expression of TGF-beta 1, -beta 2, and -beta 3 and their receptors, types I and II, at the first trimester of pregnancy. In addition, their cell-specific expression at the maternal-fetal interface was determined by in situ hybridization. RESULTS: Each isoform of TGF-beta was expressed in both decidual and villous tissues. Because most TGF-beta 1 gene expression was found in villous tissues, TGF-beta 2 mRNA was expressed preferentially in the decidual tissues. TGF-beta 3 transcripts were expressed in the nonpregnant endometrium. CONCLUSIONS: The results suggest that each isoform of TGF-beta plays some specific role in decidualization and placentation. Furthermore, it is predicted that they regulate the maternal-fetal interaction at early gestation.

Blotting, Northern↗
PubMed1998

Induction of systemic and mucosal immune responses to human immunodeficiency virus type 1 by a DNA vaccine formulated with QS-21 saponin adjuvant via intramuscular and intranasal routes.

Induction of mucosal and cell-mediated immunity is critical for development of an effective vaccine against human immunodeficiency virus (HIV). We compared intramuscular and intranasal immunizations with a DNA vaccine encoding env of HIV-1 and evaluated the QS-21 saponin adjuvant for augmentation of the systemic and mucosal immune responses to HIV-1 in a murine model. Vaccination via the two routes elicited comparable systemic immune responses, and QS-21 consistently enhanced antigen-specific serum immunoglobulin G2a (IgG2a) production, delayed-type hypersensitivity reaction, and cytolytic activity of splenocytes. Intestinal secretory IgA production and cytolytic activity of the mesenteric lymph node cells are preferentially elicited by intranasal immunization, and QS-21 augmented these activities as well. This adjuvant augmented production of interleukin-2 (IL-2) and gamma interferon (IFN-gamma) associated with decrease in IL-4 synthesis by antigen-restimulated splenocytes. The serum immunoglobulin subtype profile showed a dominant IgG2a response and less strong IgG1 and IgE production in a QS-21 dose-dependent manner. As expected, enhancements of humoral and cell-mediated immune responses by QS-21 were abrogated by treatment with anti-IL-2 and anti-IFN-gamma monoclonal antibodies. These results suggest that the intranasal route of DNA immunization is more efficient than the intramuscular route in inducing mucosal immunity mediated by sIgA and mesenteric lymphocytes. Furthermore, QS-21 is able to act as a mucosal adjuvant in DNA vaccination and demonstrates its immunomodulatory property via stimulation of the Th1 subset. This study emphasizes the importance of the route of immunization and the use of an adjuvant for effective DNA vaccination against HIV-1.

Adjuvants, Immunologic↗
PubMed1998

Control of epilepsy associated with cerebral arteriovenous malformations after radiosurgery.

OBJECTIVE: To investigate the effect of radiosurgery for symptomatic epilepsy associated with cerebral arteriovenous malformations (AVMs). METHODS: Thirty five patients with unruptured epileptogenic AVMs were studied with a mean follow up of 43.0 months. The duration of epilepsy before radiosurgery ranged from 2 months to 21 years (mean 2.8 years). Fifteen patients showed partial seizures; eight of these had associated secondary generalisation. The remaining 20 patients showed only generalised seizures without preceding focal seizures. RESULTS: At the final follow up examination, 28 patients remained seizure free, whereas seizures continued in seven. Variables significantly associated with continuity of seizures after radiosurgery were the number of seizures before therapy (p<0.01) and duration of epilepsy (p<0.05). According to Engel's classification, the 10 patients with intractable seizures before treatment included five with grade I, four with grade III, and one with grade IV. The frequency of seizures began to decrease several months after radiosurgery; much shorter than the time required for morphological change in the AVMs. CONCLUSIONS: Radiosurgery seems to be beneficial for seizure control in patients with unruptured epileptogenic AVM.

Adolescent↗
PubMed1998

Subdural empyema caused by hematogenous dissemination from an abscess in thigh to a preexisting chronic subdural hematoma--case report.

A 63-year-old male with a preexisting chronic subdural hematoma presented with progressive confusion and left hemiparesis as well as high fever. Subdural empyema was strongly suspected. At surgery, the empyema was encapsulated by definite inner and outer membranes. Cultures isolated from the subdural fluid and from an abscess of his left thigh yielded methicillin-resistant Staphylococcus aureus. A pulsed-field gel electrophoresis showed these two strains were genetically identical. Hematogenous infection of a preexisting subdural hematoma is an extremely rare cause of subdural empyema.

Abscess↗
PubMed1998

Arteriovenous malformations in the basal ganglia and thalamus: management and results in 101 cases.

OBJECT: Because arteriovenous malformations (AVMs) in the basal ganglia and thalamus are difficult to treat, the authors conducted a retrospective study to determine the best management strategy for these lesions. METHODS: The authors reviewed the management and outcome in 101 patients with AVMs treated between 1971 and 1995. In 15 conservatively treated patients, hemorrhage occurred in 71.4% (annual rate 11.4%), and the morbidity and mortality rates were 7.1% and 42.9%, respectively, during a mean follow-up period of 6.6 years. Total microsurgical resection was performed in 15 patients with no mortality resulting, but motor function deteriorated permanently in three of them (20%). Postoperative morbidity correlated well with the location of the AVM and with preoperative motor function. In cases of lenticular AVMs without motor weakness, a postoperative decrease in motor function was significantly more common than in the remaining patients. In patients with motor weakness before surgery, AVMs in the thalamus or caudate nucleus were successfully resected. Among 66 patients treated with gamma knife radiosurgery, three had permanent radiation-induced neurological deficits, and three others experienced bleeding (new bleeding in one case and rebleeding in two). The treatment-associated morbidity rate was 6.7%, and the actuarial rate of complete obliteration was 85.7% at 2.5 years. In five patients treated with embolization alone, the morbidity and mortality rates associated with the procedure or bleeding were 40% and 20%, respectively. The morbidity and mortality rates in the pre-gamma knife era were 22.2% and 22.2%, whereas those for the post-gamma knife era are currently 10.4% and 1.5%, respectively. CONCLUSIONS: These results indicate that conservatively treated AVMs are more likely to bleed and thus produce a high incidence of patient mortality. Multimodal treatment including radiosurgery, microsurgery, and embolization improved clinical outcomes by making it possible to treat difficult cases successfully.

Adolescent↗
PubMed1998

[A case of pulmonary sarcoidosis with multiple cavitation and pneumothorax].

We describe a rare case of pulmonary sarcoidosis with multiple cavitation and pneumothorax. A 32-year-old woman was admitted to our hospital with a dry cough and an interstitial shadow with dense infiltrates in both upper lungs and cavitation in the right upper lung on chest roentgenogram and CT. Laboratory tests revealed an elevated level of serum lysozyme. BAL fluid demonstrated a high proportion of lymphocytes with an increased CD4/CD8 ratio, compatible with sarcoidosis. Transbronchial lung and skin biopsies showed evidence of noncaseating epithelioid-cell granuloma, and a diagnosis of sarcoidosis was made. Although pneumothorax appeared in the left lung on chest roentgenogram during clinical observation conservative treatment without corticosteroids or any other therapy for a follow-up period of 3 years resulted in improvement of her clinical condition and abnormal X-ray findings.

Adult↗
PubMed1998

[Clear cell ependymoma--a case report].

A case of intraaxial clear cell ependymoma is reported. A 46-year-old man complained of right hemiparesis. CT scan showed a mass lesion on the median plane with a huge cyst in the left frontal lobe. MRI showed an iso-low intensity mass by T1-weighted image. The tumor was heterogeneously enhanced by Gd-DTPA and the wall was enhanced as well. Angiogram revealed a tumor stain from the right internal carotid artery. The main mass of the tumor was totally removed but the cystic wall was left removed. Histopathological examination revealed clear cell ependymoma. Immunohistochemical examination revealed that, although vimentin and NSE were positive, GFAP, synaptophysin and S-100 were negative. Ultrastructual examination revealed cilia, microvilli and desmosomal junctions. The patient fully recovered after operation and showed no sign of recurrence after an year of follow-up. Clear cell ependymoma is a rare variant of ependymoma. Ultrastructual examination was more useful than immunohistochemical examination for diagnosis.

Brain Neoplasms↗
PubMed1998

Isolation and characterization of human cathepsin V: a major proteinase in corneal epithelium.

PURPOSE: To isolate and characterize a novel cathepsin gene, as part of the systematic isolation of genes uniquely active in corneal epithelium. METHODS: For the isolation of a full-length cDNA clone, a probe was selected from a set of expressed sequence tag clones classified as unique to corneal epithelium. Inserted cDNA was introduced into insect cells using a baculovirus expression system, and the secretion of recombinant protein was identified using antisera against a synthetic peptide. Proteolytic activity was determined using bovine serum albumin (BSA) as substrate. The expressions of the novel cathepsin in human cornea and other tissues were examined by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The full-length cDNA clone encoded a peptide of 334 amino acids with 82% identity with bovine cathepsin L and 77% identity with human cathepsin L when aligned. The recombinant protein produced in the baculovirus expression system cleaves BSA, and its activity was inhibited by the cysteine proteinase inhibitors E-64 and leupeptin, but not by pepstatin A, phenylmethylsulfonyl fluoride, and EDTA. By RT-PCR, a low level of expression was observed in some other epithelial tissues of ectodermal origin, but only in cornea was it higher than cathepsin L, which is known to be a general lysosomal cathepsin. Cathepsin V protein was detected in human corneal epithelium by western blot analysis, but not in tear fluid. CONCLUSIONS: The amino acid homology and proteolytic activity of the recombinant protein indicate that the novel gene is a new member of the cathepsins that have features of cysteine proteinase. Its uniquely high expression in corneal epithelium strongly implies an important role in corneal physiology.

Amino Acid Sequence↗
PubMed1998

[SLE with interstitial pneumonia during cyclophosphamide pulse therapy].

A 49 year-old man was admitted for edema and renal impairment due to SLE. Since he did not improve with predonisolone and methylprednisolone pulse therapy, cyclophosphamide pulse therapy (300 mg div.) was administered. The patient subsequently developed a fever, dyspnea and cough, and interstitial regions of the lungs exhibited shadows on X-ray and CT. The patient also suffered hypoxemia and poor lung function. Since several culture tests and viral antibody tests were negative for infection, antibiotics were not effective, and TBLB indicated interstitial pneumonia, which we speculated was induced by cyclophosphamide. However, this was such a severe case of interstitial pneumonia that it could not be cured merely by discontinuing the cyclophosphamide, but it did improve immediately after starting methylprednisolone pulse therapy. The incidence of cyclophosphamide-induced interstitial pneumonia is very low, but the mortality rate is high. Since cyclophosphamide pulse therapy is often used to treat SLE, attention should be focused on the incidence of interstitial pneumonia.

Cyclophosphamide↗
PubMed1997

Molecular cloning and expression of a novel human aquaporin from adipose tissue with glycerol permeability.

In a systematic analysis of genes expressed in human adipose tissue, we detected a novel gene that is expressed uniquely in adipose tissue. The sequence showed that it encodes a 342-amino-acid protein containing six putative transmembrane domains, and is a new member of the aquaporin family of water-selective membrane channels. We named this gene aquaporin 9. It features a cyclic-AMP protein kinase phosphorylation consensus site in the NH3-terminal domain. Expression of the cRNA in Xenopus oocytes yielded a 7-fold increase in osmotic water permeability blocked by 0.3 mM HgCl2, and also facilitated the uptake of glycerol. Northern blot analysis demonstrated that the mRNA is abundant in adipose tissue, but not in other tissues. Thus, this gene product may participate in glycerol transport in adipocytes.

Adipose Tissue↗
PubMed1997

Cationic liposomes are a strong adjuvant for a DNA vaccine of human immunodeficiency virus type 1.

Liposomes have been widely used to enhance the immune response. In the present investigation, we studied their in vivo immunomodulation of an HIV-1-specific DNA vaccine candidate (pCMV160/REV) constructed with the cytomegalovirus (CMV) promoter-conjugated HIV-1 env and rev DNA plasmids. By immunizing with pCMV160/REV and cationic liposomes through various routes (intramuscular, intraperitoneal, subcutaneous, intradermal, and intranasal), we induced higher levels of both antibody production and delayed-type hypersensitivity (DTH) than by using DNA vaccine alone. The HIV-1-specific cytotoxic T lymphocyte (CTL) activity was observed to be stronger on immunization with the DNA vaccine and cationic liposome combination. The intramuscular, intraperitoneal, and intranasal inoculation routes were more effective in inducing strong DTH and antibody responses than the subcutaneous and intradermal routes. Taken together, these results suggest that cationic liposomes can be highly effective when used with DNA vaccines and administered by various routes.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Cloning of a cDNA encoding a novel sugar transporter expressed in the neonatal mouse hippocampus.

While analyzing active genes in the neonatal mouse hippocampus, we observed several novel genes that were abundantly expressed in this tissue. We report here cloning and sequencing of one of these transcripts, HiAT1 (Hippocampus Abundant Gene Transcript 1). The mRNA was 2.7 Kb in length, and the deduced amino acid sequence consisted of 490 amino acids with characteristics typical of members of the sugar transporter family. However, its overall sequence homology to known transporter cDNAs was only about 30%, suggesting strongly that it represents a novel sugar transporter gene. Northern hybridization analyses showed this transcript is detected in adult and embryonic brains, as well as in other tissues.

Amino Acid Sequence↗
PubMed1997

Bidirectional regulation of telomerase activity in a subline derived from human lung adenocarcinoma.

Telomerase is active in germline cells and tumor cells, but is either not expressed or is repressed in a majority of somatic cells. The regulation mechanism of telomerase activity has lately drawn considerable attention for the possible use of telomerase inhibitors for anti-cancer therapy. We analyzed the regulation mechanism of telomerase activity in the human lung adenocarcinoma cell line A549 and its subline A5DC7 which shows impaired tumor phenotypes. Although A549 and A5DC7 cells have similar growth potentials, when cultured in medium supplemented with 5% fetal bovine serum A5DC7 cells demonstrated a remarkable negative regulation of telomerase activity and telomere shortening. After the long-term culture, A5DC7 cells showed a large senescent cell-like morphology, arrested growth at the 106 population doubling level and entered senescence which was demonstrated by expression of the beta-galactosidase senescence marker. When the serum concentration was raised from 5% to 10% for the senescent A5DC7 cells, telomerase reactivation and telomere lengthening occurred as well as resumption of proliferation. These results demonstrate that the growth arrest seen in senescent A5DC7 cells is reversible and that telomerase activity is also bi-directionally regulated in A5DC7 cells, an event which could not be observed in normal senescent cells. This indicates that stringent telomerase repression and complete growth arrest concomitant with cellular senescence is collapsed in senescent A5DC7 cells in response to exogenous signals. Our study suggests that cellular senescence progresses and/or is regulated at multiple levels.

Adenocarcinoma↗