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K Hamaguchi

Publications and source records attributed to K Hamaguchi.

At least 127 records · Page 7Linked to original sources
PubMed1991

Structure of the active 27-residue fragment of human calpastatin.

A synthetic 27-residue peptide corresponding to exon 1B of the endogenous inhibitor calpastatin contains a well-conserved region and has an ability to inhibit the cysteine endopeptidase calpain specifically. We examined the solution structure of this peptide in DMSO-d6 by two-dimensional 1H NMR spectroscopy. Although regular secondary structures such as alpha-helix and beta-sheet were not found, the region from Ile18 to Arg23 formed a well-defined structure with a type I beta-turn. This region coincided well with the highly conserved region of calpastatin. The result strongly suggests that this turn structure is essential for the inhibitory activity of calpastatin.

Amino Acid Sequence↗
PubMed1991

Conformation and disulfide bond formation of the constant fragment of an immunoglobulin light chain: effect of truncation at the C-terminal region.

Constant fragments with different carboxyl terminals, CL(109-211), CL(109-207), and CL-(109-200), were prepared by limited carboxypeptidase P or Y proteolysis of the constant fragment, CL-(109-214), of a type lambda immunoglobulin light chain, and their conformations and stabilities, and formation of the disulfide bond from the reduced fragments, were studied. No change in conformation or stability was observed on removal of three residues from the C-terminal end. Removal of seven or more residues from the C-terminal end destabilized the CL fragment. The rate of disulfide bond formation from reduced CL(109-207) was about 7 times faster than that for CL(109-214). These findings suggest that elongation of the polypeptide chain at least beyond the 207th residue is necessary for folding of the CL fragment into a definite conformation.

Amino Acid Sequence↗
PubMed1991

Use of fluorescence energy transfer to characterize the compactness of the constant fragment of an immunoglobulin light chain in the early stage of folding.

The CL fragment of a type-kappa immunoglobulin light chain in which the C-terminal cysteine residue was modified with N-(iodoacetyl)-N'-(5-sulfo-1-naphthyl)ethylenediamine (CL-AEDANS fragment) was prepared. This fragment has only one tryptophan residue at position 148. The compactness of the fragment whose intrachain disulfide bond was reduced in order for the tryptophan residue to fluoresce (reduced CL-AEDANS fragment) was studied in the early stages of refolding from 4 M guanidine hydrochloride by fluorescence energy transfer from Trp 148 to the AEDANS group. The AEDANS group attached to the SH group of a cysteine scarcely fluoresced when excited at 295 nm. For the reduced CL-AEDANS fragment, the fluorescence emission band of the Trp residue overlapped with the absorption band of the AEDANS group, and the fluorescence energy transfer was observed between Trp 148 and the AEDANS group in the absence of guanidine hydrochloride. In 4 M guanidine hydrochloride, the distance between the donor and the acceptor was larger, and the efficiency of the energy transfer became lower. The distance between Trp 148 and the AEDANS group for the intact protein estimated by using the energy-transfer data was in good agreement with that obtained by X-ray crystallographic analysis. By the use of fluorescence energy transfer, tryptophyl fluorescence, and circular dichroism at 218 nm, the kinetics of unfolding and refolding of the reduced fragment were studied. These three methods gave the same unfolding kinetic pattern. However, the refolding kinetics measured by fluorescence energy transfer were different from those measured by tryptophyl fluorescence and circular dichroism, the latter two giving the same kinetic pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Circular Dichroism↗
PubMed1991

Activated T lymphocyte subsets in experimental allergic neuritis.

Changes in activated T cell subsets in peripheral blood were examined during the course of experimental allergic neuritis (EAN), using two-color immunofluorescence flow cytometry. Both CD4+ and CD8+ activated T cells decreased transiently before the onset of clinical signs, and increased just around the time of onset of the disease. In contrast, during the recovery phase, the numbers of CD4+ activated T cells returned to the normal range, whereas CD8+ activated T cells continued to increase. These findings imply that activation of CD4+ helper/inducer cells contributes mainly to the evolution of EAN, and that of CD8+ suppressor cells are necessary for recovery.

Animals↗
PubMed1991

Study of lupus nephritis in males.

Clinical and pathological findings were studied in 23 male patients with lupus nephritis who were followed up for a period of 41 +/- 36 months after renal biopsy. Age at renal biopsy was 31 +/- 14 years and 19 patients (83 per cent) were between 15 and 50 years old. C3 and C4 levels were below normal in 23 (100 per cent) and 16 (70 per cent) respectively, CH50 was less than 25 u/ml in 67 per cent, and antinuclear and anti-DNA antibodies were found in 87 per cent and 82 per cent respectively. Serum albumin level increased from 2.9 +/- 0.8 g/dl to 3.7 +/- 0.8 g/dl during the follow up period (p less than 0.01), while urinary protein decreased from 2.0 +/- 2.3 g/day to 1.4 +/- 2.5 g/day. There was a significant improvement in the degree of haematuria (p less than 0.01), but serum creatinine levels showed no change (mean 1.5 mg/ml). Active proliferative lupus nephritis of moderate or severe degree was observed in 65 per cent of patients at the initial biopsy. A trend to regression in this activity was seen in most serial biopsies, but the chronicity index showed a slight increase. These data demonstrate that systemic lupus erythematosus in males, in comparison to our previous report of the disease in female patients, is accompanied by more active nephritis, but that it follows a benign course with therapy.

Adolescent↗
PubMed1991

NIT-1, a pancreatic beta-cell line established from a transgenic NOD/Lt mouse.

NOD/Lt mice harboring a hybrid rat insulin-promoter/SV40 large T-antigen gene spontaneously develop beta-cell adenomas. NIT-1 is a pancreatic beta-cell line established from one of these transgenic mice. Immunocytochemical staining of passage 18 cells showed most contained insulin, with less than 5% containing glucagon, and none containing pancreatic polypeptide or somatostatin. Glucagon content radioimmunoassayed in cell extracts was only 0.27% of the insulin content. Two-hour insulin secretion at 16.5 mM glucose was 638 ng/10(6) cells (41% of intracellular content) compared to only 1.3 ng glucagon (32% of intracellular content). Stimulated insulin secretion was consistently observed in response to 11 and 16.5 mM glucose between passages 11 and 19. At passage 19, both theophylline and tolbutamide stimulated insulin secretion at 5.5 mM glucose. Northern-blot analysis confirmed high levels of insulin mRNA but only trace glucagon mRNA and undetectable somatostatin mRNA. Interferon-gamma (IFN-gamma)-induced MHC class I RNA expression was correlated with markedly increased antigen expression at the cell surface. Similarly, a MHC-linked "occult" class I-like antigen detected by Cr release assay only after exposure of standard NOD/Lt islet cells to IFN-gamma was strongly induced by IFN-gamma in NIT-1 cells. Cell surface MHC class II antigen was not constitutively expressed on NIT-1 cells and could not be detected after IFN-gamma incubation, despite demonstration of IFN-gamma-induced Aa, Ab, and Li invariant-chain RNA transcripts. Similarly IFN-gamma induction of intercellular adhesion molecule 1 (Icam-1) transcripts was not accompanied by demonstrable cell surface expression of ICAM-1 antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1991

Long-term results of immunochemotherapy for advanced ovarian cancer.

Fifty-one patients with stage III and IV ovarian adenocarcinoma underwent initial cytoreductive surgery at Kurume University Hospital between January 1982 and October 1985. They were assigned postoperatively by randomized trials to immunochemotherapy or chemotherapy alone. Of all 51 patients, long-term results of immunochemotherapy for 43 patients were evaluated versus radicality of initial cytoreductive surgery. As a result, the group of patients treated with immunochemotherapy tended to have a better prognosis than the group of patients treated with chemotherapy alone, whereas no statistical difference was observed between the two groups. Moreover, no significant difference was observed in the monitoring of OKT 4/8 ratio between the two groups. However, immunochemotherapy produced a favorable prognosis in the patients with residual disease of greater than 2 cm in diameter at initial surgery. In conclusion, these data suggested that immunochemotherapy may have some impact on survival of patients with ovarian adenocarcinoma.

Adenocarcinoma↗
PubMed1991

[An autopsy case of Gerstmann-Sträusser-Scheinker's disease with spastic paraplegia as its principal feature].

A 38-year-old woman developed slowly progressive gait disturbance. At age 39 years she was admitted to our department because she could not walk without assistance. On neurological examination she was alert with normal mental functions. Horizontal nystagmus on both sides, minimal clumsiness in the left upper extremity on the finger-to-nose test and moderate degree of spasticity in bilateral lower extremities without evident motor weakness were present. The gait was spastic with small steps on a wide base. There was no sensory abnormalities. The deep tendon reflexes were hyperactive on both sides, on the lower extremities, with positive Babinski's sign. The sphincter functions were intact. During the following 5 years she gradually deteriorated and pseudobulbar palsy, emotional incontinence and the progressive dementia appeared in addition to severe spastic paraplegia. At age 45 years she was admitted to our nursing home and she died 3 months later, of pneumonia, on 6 years after the onset of her illness. Two elder sisters of her 7 siblings had the similar neurologic illness. The brain weighed 1,060 g. There was mild atrophy of cerebrum, cerebellum and brainstem. There were neuronal loss and gliosis in layers IV-VI of cerebral cortex with no evidence of the spongy state. Cerebellar cortex, cerebellar peduncles and spinocerebellar tracts were preserved. There was marked degeneration of corticospinal tract from cerebral peduncle to lateral funiculus of lumbar spinal cord. The most prominent feature was appearance of numerous multicentric amyloid plaques, which were marked in layers I-III of cerebral cortex and to a lesser extent in corpus striatum, hippocampus and the white matters of cerebrum and cerebellum.(ABSTRACT TRUNCATED AT 250 WORDS)

Amyloid↗
PubMed1991

[A case of adrenoleukodystrophy presenting large lesion of the cerebellar white matter and dentate nuclei on brain CT and MRI].

A 17-year-old male was admitted to our hospital complaining of slowly progressive gait disturbance. His initial symptoms were behavioral change and mental deterioration starting at age 16. One year later, unstable gait and speech disturbance appeared. On admission, neurological findings included slight dementia, visual loss, scanning speech, dysdiadochkinesis, pathological reflexes, spastic and ataxic gait. Brain CT scan showed symmetrical low density areas in the dentate nuclei and cerebellar white matter, atrophy of the brain stem and cerebellum, and dilatation of the fourth ventricle. These findings were also confirmed by MRI. One year after admission, atrophy of the frontal, temporal, parietal lobes was noted by CT scan and MRI. The cervical and thoracic cord was observed to be atrophic by MRI. Motor nerve conduction study showed decreased velocity, suggesting the presence of peripheral neuropathy. Fatty acids analysis of plasma sphingomyelin revealed marked increased in very long chain fatty acids, which was compatible with a diagnosis of adrenoleukodystrophy (ALD). However, the term "adrenoleukomyeloneuropathy (ALMN)" was considered more preferable, since the spinal cord and peripheral nerves were involved in this case. Prominent changes in the cerebellar white matter and dentate nuclei at early stage on CT and MRI were not described in the previous publications. Our paper, hence, may be the first one to report such findings and may contribute to early recognition of ALD or ALMN.

Adolescent↗
PubMed1991

[Central acetylcholine receptor function in patients with myasthenia gravis].

There are some reports on central nervous system involvements in patients with myasthenia gravis, such as abnormal EEG, and memory disturbance. Myasthenia gravis is considered to be an autoimmune disease with antibodies against the skeletal nicotinic acetylcholine receptor (n-AChR). ACh is a neurotransmitter in osmoregulation. Neuronal n-AChR plays an important role in this regulation. In order to investigate the function of neuronal n-AChR in patients with myasthenia gravis, we performed a 5% hypertonic saline infusion test on 9 patients and 9 healthy volunteers. We also carried out an orthostatic stress test (50 degree passive head-up tilt) on 6 patients with myasthenia gravis and 5 healthy controls to evaluate arginine-vasopressin (AVP) release via baroreceptors. Three of the 9 MG patients showed exaggerated plasma AVP secretion, and one revealed a blunt response to hypertonic stimulation. Both patients and controls did not differ significantly in terms of plasma AVP response to orthostatic stress. To conclude, we suggest the possibility that function of neuronal n-AChR in the central nervous system is impaired in patients with myasthenia gravis.

Adult↗
PubMed1990

Flow cytometric analysis of nuclear DNA content in patients with recurrent epithelial ovarian cancer.

Numerous reports have recently indicated that the DNA content of various malignant tumors can be of great value in predicting biological behavior and prognosis of the tumors. This study was undertaken to determine the nuclear DNA content in the primary and recurrent ovarian carcinoma of the same 20 consecutive patients by flow cytometry, and the results on clinical outcome was examined. The tissue samples of the recurrent tumors were obtained at second-look laparotomy. Of the primary tumors, 12 were diploid, 4 were pure aneuploid, and 4 were "mosaic", while of the recurrent tumors, 17 were diploid and 3 showed pure aneuploid. No significant difference of the DNA index at recurrence was observed. DNA ploidy was preserved in 12 out of 20 patients at recurrence. The time to recurrence after the initial treatment showed no significant difference versus DNA ploidy and change of ploidy. The sites and status of recurrence differed by DNA ploidy. At recurrence, the patients with DNA diploidy had a tendency to survive longer than those with DNA aneuploidy. The determination of DNA ploidy at recurrence may be useful as a variable parameter in predicting the survival of patients with ovarian carcinomas.

DNA, Neoplasm↗
PubMed1990

[Platinum-based combination chemotherapy for malignant mixed mesodermal tumor of the ovary: a case report].

Malignant mixed mesodermal tumor (MMMT) of the ovary is a rare neoplasm with a dismal prognosis and therapeutic modalities remain an enigma. The present paper describes our experience with an impressive response utilizing a cis-platinum based combination chemotherapy in a 56-year-old female with this disease and a review of the literature. The patient was treated with PAIE therapy following a cytoreductive surgery. Two further courses of a single-agent chemotherapy of cis-platinum were given. A PR was obtained after completion of the third course and tumor markers showed a prompt fall with a tumor response. Nevertheless, no further therapy was performed because of her refusal. She expired 5 months after diagnosis because of tumor progression.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Chemical modification of tryptophan residues and stability changes in proteins.

The role of tryptophan residues in the stability of proteins was studied by ozone oxidation, which causes a small change in the tryptophan side chain. Trp 187 of the constant fragment of a type lambda immunoglobulin light chain, Trp 59 of ribonuclease T1, and Trp 62 of hen egg white lysozyme were oxidized specifically by ozone to N'-formylkynurenine or kynurenine. Judging from their circular dichroic and fluorescence spectra, these modified proteins were found to be the same as those of the respective intact proteins. However, even the slight modification of a single tryptophan residue produced a large decrease in the stability of these proteins to guanidine hydrochloride and heat. The smaller the extent of exposure of the tryptophan residue, the greater the effect of the modification on the stability. The formal kinetic mechanism of unfolding and refolding by guanidine hydrochloride of the CL fragment was not altered by tryptophan oxidation, but the rate constants for unfolding and refolding changed. The thermal unfolding transitions were analyzed to obtain the thermodynamic parameters. The enthalpy and entropy changes for the modified proteins were larger than the respective values for the intact proteins.

Animals↗
PubMed1990

Conformations of isolated fragments of pancreatic polypeptide.

In spite of its short polypeptide chain, the pancreatic polypeptide molecule consists of a polyproline II type helix and alpha-helix. To understand the stability and formation of the alpha-helical region, we prepared some peptide fragments including the helical segment of chicken pancreatic polypeptide and studied their conformations by circular dichroism (CD). PP7-36 (a peptide fragment corresponding to residues 7-36 of chicken pancreatic polypeptide) showed a CD spectrum characteristic of the helix at pH 4.6 and at peptide concentrations as low as 1 microM. PP11-36 was able to form a helical conformation only at high peptide concentrations and not at concentrations lower than 10 microM. However, acetyl PP11-36 (in which the alpha-amino group is acetylated so that no positive charge exists at the N terminus) was able to form the helical conformation at pH 4.6 and at the peptide concentrations where PP11-36 could not. Succinyl PP12-36 (in which the alpha-amino group is succinylated to introduce a negative charge) was also able to form the helical conformation. The CD spectra of PP12-36 and PP13-36 were not characteristic of the helical conformation at all the pH values and peptide concentrations studied. Acetyl PP13-36, which has no charge at the N terminus, did not form the helix. On the other hand, succinyl PP13-36, which has a negative charge at the N-terminal end, did form the helix at pH 4.6. These findings indicate that the presence of the negative charge of carboxylate at the N-terminal region of a peptide fragment is important for helix formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Acylation↗
PubMed1990

Global fluctuations of the immunoglobulin domains under physiological conditions.

Hydrogen-exchange rates of the indole NH proton of a tryptophan residue, buried fully in the interior of each of the constant (CL) and variable (VL) fragments of a type-kappa-immunoglobulin light chain, were studied at various pH values and at 25 degrees C under 1H-nuclear magnetic resonance. The activation energies for the exchange reactions were determined also and compared with those for the unfolding reactions of these fragments induced by guanidine hydrochloride. The pH profiles of the exchange rates of the CL(kappa) and VL(kappa) fragments were very similar to that for a CL (lambda) fragment reported previously. It was found that the CL (kappa) and VL (kappa) fragments as well as the CL (lambda) fragment undergo a global unfolding transition with a conformation very similar to that of the fully unfolded state induced by guanidine hydrochloride even under physiological conditions.

Bence Jones Protein↗
PubMed1990

Cause of death among patients with Parkinson's disease: a rare mortality due to cerebral haemorrhage.

Causes of death, with special reference to cerebral haemorrhage, among 240 patients with pathologically verified Parkinson's disease were investigated using the Annuals of the Pathological Autopsy Cases in Japan from 1981 to 1985. The leading causes of death were pneumonia and bronchitis (44.1%), malignant neoplasms (11.6%), heart diseases (4.1%), cerebral infarction (3.7%) and septicaemia (3.3%). Cerebral haemorrhage was the 11th most frequent cause of death, accounting for only 0.8% of deaths among the patients, whereas it was the 5th most common cause of death among the Japanese general population in 1985. The low incidence of cerebral haemorrhage as a cause of death in patients with Parkinson's disease may reflect the hypotensive effect of levodopa and a hypotensive mechanism due to reduced noradrenaline levels in the parkinsonian brain.

Aged↗