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Biomedical subjects

H Okamoto

Publications and source records attributed to H Okamoto.

At least 271 records · Page 15Linked to original sources

Anti-rheumatic compound aurothioglucose inhibits tumor necrosis factor-alpha-induced HIV-1 replication in latently infected OM10.1 and Ach2 cells.

NF-kappaB is a potent cellular activator of HIV-1 gene expression. Down-regulation of NF-kappaB activation is known to inhibit HIV replication from the latently infected cells. Gold compounds have been effectively used for many decades in the treatment of rheumatoid arthritis. We previously reported that gold compounds, especially aurothioglucose (AuTG) containing monovalent gold ion, inhibited the DNA-binding of NF-kappaB in vitro. In this report we have examined the efficacy of the gold compound AuTG as an inhibitor of HIV replication in latently infected OM10.1 and Ach2 cells. Tumor necrosis factor (TNF)-alpha-induced HIV-1 replication in OM10.1 or Ach2 cells was significantly inhibited by non-cytotoxic doses of AuTG (>10 microM in OM10.1 cells and >25 F.M in Ach2 cells), while 25 microM of the counter-anion thioglucose (TG) or gold compound containing divalent gold ion, HAuCl3, had no effect. The effect of AuTG on NF-kappaB-dependent gene expression was confirmed by a transient CAT assay. Specific staining as well as electron microscopic examinations revealed the accumulation of metal gold in the cells, supporting our previous hypothesis that gold ions could block NF-kappaB-DNA binding by a redox mechanism. These observations indicate that the monovalent gold compound AuTG is a potentially useful drug for the treatment of patients infected with HIV.

Anti-HIV Agents↗

Epidermal changes in cutaneous lesions of sarcoidosis.

The essential histologic finding of cutaneous sarcoidosis is a noncaseating epithelioid cell granuloma in the dermis or, infrequently, in the subcutaneous tissues. However, there have been cases of cutaneous sarcoidosis with clinical appearances altered by epidermal changes such as ulcers, the formation of psoriasiform or verrucous plaques, and by hypopigmentation. In this study, histologic examinations of the epidermis were performed in cutaneous lesions of 62 cases of sarcoidosis. Seventy-nine percent (49/62) showed epidermal changes including hyperkeratosis (8/49), parakeratosis (10/49), acanthosis (6/49), and epidermal atrophy (35/49). Lymphoid cells extended into the epidermis in 50 of 62 cases. The infiltration patterns were in the forms of a spongiotic reaction (21/50), lichenoid tissue reaction (9/50), and simple exocytosis without epidermal vesiculation (20/50). Immunohistochemical studies showed that the lymphoid cells in the epidermis expressed CD3, 8, 45RO, and 11a. The epidermal changes overlying the granulomatous lesions contribute to the variety of clinical manifestations and are in part associated with the pathogenesis of cutaneous sarcoidosis.

Atrophy↗

Effect of prolonged treatment with amlodipine on enhanced vascular contractility in cardiomyopathic hamsters.

This study examined the effects of prolonged treatment with amlodipine on the enhanced vascular contractions in dilated cardiomyopathic (CM) hamsters. From the ages of 5 to 20 weeks, CM hamsters (BIO 53.58) orally received amlodipine. Then we compared the contractile responses to vasoconstrictors in aortas and mesenteric arteries from CM hamsters with or without treatment with those in the arteries from controls (F1b). We also investigated the effect of amlodipine treatment on the Ca2+ sensitivity of tension in beta-escin-skinned smooth muscle of mesenteric artery. The contractile responses to phenylephrine, angiotensin II, and high K+ in both aorta and mesenteric artery were greatly enhanced in CM hamsters compared with controls. Amlodipine treatment slightly but significantly inhibited the enhanced responses in aorta but did not alter the responses in mesenteric arteries. The Ca2+ sensitivity of tension was significantly increased in CM hamster preparations, which was unaffected by amlodipine treatment. These data indicate that amlodipine treatment differentially affects the enhanced responses to vasoconstrictors between large and small blood vessels from CM hamsters. The lack of effect of amlodipine treatment on the responsiveness of CM mesenteric artery leads to the suggestion that the preventive effect of amlodipine on focal myocytolytic necrosis of cardiomyocytes, which was previously reported to be the main cause of cardiomyopathy, results from an action on cardiomyocytes.

Actin Cytoskeleton↗

Ultrasonographic evidence of association of polyps and stones with gallbladder cancer.

OBJECTIVE: The purpose of this study was to evaluate the level of gallbladder cancer risk associated with polyps and stones of the gallbladder by ultrasound examinations. METHODS: We investigated abdominal ultrasonographic findings for gallstones and polyps of the gallbladder and the relationship of these findings to malignancy in 194,767 asymptomatic participants in health screening examinations. RESULTS: Gallstones were detected in 7,985 participants (4.1%), at a prevalence of 5.3% in male and 4.5% in female participants. The prevalence was highest in the participants' seventh decade, followed by the sixth and the fifth decades, in both male and female participants. Polyps were found in 10,926 (5.6%), at a prevalence of 6.9% in the male and 4.5% in the female participants. In the male participants, prevalence was highest in the fourth decade, followed by the third and the fifth decades, whereas in the female participants it was highest in the fifth decade, followed by the fourth and third. High prevalence of polyps > or = 10 mm in diameter was found in the fifth to seventh decades in both sexes. Nineteen participants (0.01%) were diagnosed as having gallbladder cancer, and many of them were in the sixth or seventh decade in both sexes. Patients with stones showed a higher prevalence of gallbladder cancer. This difference was shown to be statistically significant by age-adjusted analysis (p < 0.01). The age distribution of the participants with polyps > or = 10 mm in diameter was correlated with that of patients diagnosed with gallbladder cancer. Furthermore, polyp incidence was significantly related to cancer by statistical analysis (p < 0.01). CONCLUSION: These results suggest an association between gallstone or polyp of the gallbladder and increased risk of malignancy, implying that an etiological association may also exist.

Adult↗

Quasispecies of TT virus (TTV) with sequence divergence in hypervariable regions of the capsid protein in chronic TTV infection.

Three hypervariable regions were identified in a central portion of open reading frame 1 of TT virus DNA, which codes for a putative capsid protein of 770 amino acids. TT virus circulates as quasispecies, with many amino acid substitutions in hypervariable regions, to evade immune surveillance of the hosts and to establish a persistent infection.

Acute Disease↗

Beneficial effect of myocardial angiogenesis on cardiac remodeling process by amlodipine and MCI-154.

The present study examined the effect of long-term treatment with amlodipine and MCI-154 (a Ca2+ sensitizer) on progressive cardiac dysfunction and microvasculature in the dilated cardiomyopathic (DCM) hamster heart. After treatment of DCM hamsters (Bio 53.58) with amlodipine or MCI-154 for 15 wk from the age of 5 wk, amlodipine and MCI-154 were found to cause an increase in left ventricular percent fractional shortening and decreases in left ventricular diastolic dimension and isovolumic relaxation time in echocardiograms (P < 0.01). A hemodynamic study showed that the diastolic time constant decreased in the amlodipine-treatment group (P < 0.05). In a morphometric study employing a double-staining method that discriminated arteriolar and venular capillaries, amlodipine and MCI-154 caused increases in total capillary density (P < 0.05) and the proportion of venular capillaries (P < 0.05). Moreover, Northern blot analysis showed that the expression of mRNA for vascular endothelial growth factor was significantly increased by amlodipine and MCI-154. They preserve coronary microvasculature in the DCM hamster and might induce angiogenesis of small vessels, thereby contributing to preservation of cardiac systolic and diastolic function.

Amlodipine↗

A novel unenveloped DNA virus (TT virus) associated with acute and chronic non-A to G hepatitis.

In 1997, a novel DNA virus was isolated from the serum of a patient with posttransfusion hepatitis of unknown etiology in Japan, and it was named TT virus (TTV) after the initials of the index patient. TTV is a nonenveloped, single-stranded and circular DNA virus, and its entire sequence of approximately 3.9 kb has been determined. For being a DNA virus, TTV has a wide range of sequence divergence, allowing the classification into at least 16 genotypes separated by a sequence difference of >30% from one another. The nucleotide sequence of the noncoding region of the TTV genome is conserved, whereas that of the coding region is highly variable. TTV strains with extremely high sequence divergence are common in the same individuals, thereby indicating a mixed infection of TTV strains of different genotypes. An association is found between hepatitis of unknown etiology and the TTV genotypes which are detectable by PCR with primers deduced from the N22 region (genotype 1) in the open reading frame 1 encoding the capsid protein. It would be important to select the primers for specific detection of the TTV genotypes associated with clinical diseases, to further evaluate the capacity of TTV to induce acute and chronic liver disease as well as extrahepatic manifestations.

Base Sequence↗

Amelioration of vasospasm after subarachnoid hemorrhage in transgenic mice overexpressing CuZn-superoxide dismutase.

BACKGROUND AND PURPOSE: To clarify the effect of superoxide dismutase (SOD) on vasospasm after subarachnoid hemorrhage (SAH), we investigated sequential changes in arterial diameter after SAH in transgenic mice overexpressing CuZn-SOD (SOD-1). METHODS: SOD-transgenic mice and nontransgenic littermates (35 to 40 g) were subjected to SAH produced by endovascular perforation of left anterior cerebral artery. At 4 hours and 1, 3, 7, and 14 days after SAH, the mice were perfused with 10% formalin and consequently with a mixture of carbon black and 10% gelatin to cast all vessels. Vasospasm was evaluated by measuring the diameter of the left middle cerebral artery (MCA) with a microscope. RESULTS: In nontransgenic mice, the diameter of the MCA on day 3 after SAH (110.5+/-20.5 microm [mean+/-SD]; n=16) was significantly reduced compared with that without SAH (138.5+/-14.5 microm; n=12) (P<0.01). Moreover, on day 3 after SAH, the diameter of the MCA in SOD-transgenic mice (127. 9+/-20.2 microm; n=20) was significantly larger than that in nontransgenic mice (110.5+/-20.5 microm; n=16) (P<0.05). CONCLUSIONS: These results suggest that SOD is effective on the amelioration of vasospasm after SAH and that oxygen free radicals, particularly superoxide, play an important role in the pathogenesis of vasospasm after SAH.

Animals↗

Fibromuscular dysplasia involving coronary arteries--a case report.

The authors report a young patient with fibromuscular dysplasia involving multivessels including coronary arteries. If young patients have chest pain on effort, fibromuscular dysplasia of coronary arteries must be considered. As fibromuscular dysplasia is a chronic progressive disease and some cases progress rapidly in a few months, careful follow-up and comprehensive medical management may be necessary in such patients.

Adult↗

Direct amplification of Escherichia coli O157 vero toxin genes from human faeces by the polymerase chain reaction.

Direct amplification of DNA from clinical specimens, such as blood and faeces, by polymerase chain reaction (PCR) is most often hindered by endogenous inhibitory substances, including haemoglobin and bile acids. We tested whether Ampdirect A (Shimadzu), a novel reagent cocktail that has been shown to suppress the inhibitors in blood, is also useful for faecal samples, and found that the vero toxin genes (VT1 and VT2) of Escherichia coli O157 could be efficiently amplified from the supernatant of boiled faeces by PCR in the presence of this cocktail without prior extraction of DNA. We compared the efficiency of amplification with and without the cocktail, using the supernatant of boiled normal faeces supplemented with E. coli O157. PCR without the cocktail failed to amplify the vero toxin genes from the supernatant diluted < 6400-fold or containing > 0.02% (final concentration) of boiled faeces. By contrast, PCR with Ampdirect A amplified the toxin genes in the mixture containing as much boiled faeces as 0.5% and as few E. coli as 4 to 8 colony-forming units (CFU). The minimum limit for E. coli O157 detection by this method was estimated to be about 10(4) CFU/g faeces. The results obtained by this direct method agreed well with those obtained by the indirect method using DNA pre-extracted from patients' faeces (the detection limit being 10(3) CFU/g faeces).

Bacterial Toxins↗

Expression of REG protein during cell growth and differentiation of two human colon carcinoma cell lines.

We localized REG protein in Paneth cells and nonmature columnar cells of the human small intestinal crypts and speculated that this protein was associated with growth and/or differentiation. The aim of this study was to determine whether REG protein is present in two human colon cancer cell lines that exhibit enterocytic differentiation after confluence and to investigate changes in the level of its expression during growth and differentiation. Results were compared to those obtained on cells that remain undifferentiated. Western immunoblotting and immunofluorescence demonstrated the presence of REG protein in the three cell lines. With the antisera against human REG protein, the staining was diffusely spread throughout the cytoplasm at Day 2, and after Days 3-4 it appeared to have migrated to cell boundaries. After confluence, we observed only a punctate staining array along cell boundaries, which disappeared at Day 15. REG mRNA expression was demonstrated by RTPCR and REG mRNA hybridization until Day 13, but not after, in the three cell types. REG protein may be involved in cellular junctions. Its presence appears to be associated with the cell growth period and the protein must be downregulated when growth is achieved and differentiation is induced.

Blotting, Western↗

Phase II study of area under the plasma-concentration-versus-time curve-based carboplatin plus standard-dose intravenous etoposide in elderly patients with small-cell lung cancer.

PURPOSE: The target area under the plasma-concentration-versus-time curve (AUC)-based dosing of carboplatin using Calvert's formula is expected to result in more acceptable toxicity and greater efficacy in elderly patients with small-cell lung cancer (SCLC) than the body surface area-based dosing strategy. This phase II study was designed to determine the toxicity and efficacy of carboplatin based on Calvert's formula plus the standard dose of intravenous etoposide for elderly patients with SCLC. PATIENTS AND METHODS: Carboplatin, dosed to a target AUC of 5 x (24-hour creatinine clearance + 25), was given intravenously on day 1 and etoposide 100 mg/m(2) was given intravenously on days 1, 2, and 3. Patients aged >/= 70 years old with a performance status of 0 to 2 were eligible. RESULTS: Thirty-six patients were enrolled onto the study. The patient characteristics were as follows: median age, 73 years; limited disease (LD), 16 patients; and extensive disease (ED), 20 patients. Grades 3 and 4 leukopenia occurred in 57% and 3% of patients, and grades 3 and 4 thrombocytopenia occurred in 40% and 11% of patients, respectively. There was one treatment-related death due to hemoptysis. Other toxicities were relatively mild. There were two complete responses and 25 partial responses, for a response rate of 75%. The median survival time was 10.8 months (LD, 11.6 months; ED, 10.1 months), and the 1-year survival rate was 47%. CONCLUSION: This carboplatin/etoposide combination chemotherapy is an active and relatively nontoxic regimen in elderly patients with SCLC, which suggests that the combination may be suitable for randomized controlled trials.

Aged↗

F-spondin and mindin: two structurally and functionally related genes expressed in the hippocampus that promote outgrowth of embryonic hippocampal neurons.

Extracellular matrix (ECM) proteins play an important role in early cortical development, specifically in the formation of neural connections and in controlling the cyto-architecture of the central nervous system. F-spondin and Mindin are a family of matrix-attached adhesion molecules that share structural similarities and overlapping domains of expression. Genes for both proteins contain a thrombospondin type I repeat(s) at the C terminus and an FS1-FS2 (spondin) domain. Both the vertebrate F-spondin and the zebrafish mindins are expressed on the embryonic floor plate. In the current study we have cloned the rat homologue of mindin and studied its expression and activity together with F-spondin in the developing rodent brain. The two genes are abundantly expressed in the developing hippocampus. In vitro studies indicate that both F-spondin and Mindin promote adhesion and outgrowth of hippocampal embryonic neurons. We have also demonstrated that the two proteins bind to a putative receptor(s) expressed on both hippocampal and sensory neurons.

Amino Acid Sequence↗

Lactose as a low molecular weight carrier of solid dispersions for carbamazepine and ethenzamide.

Solid dispersions of carbamazepine or ethenzamide were prepared by melting and rapid cooling with liquid nitrogen using lactose as a carrier. The physical characteristics of these solid dispersions were investigated by powder X-ray diffraction, differential scanning calorimetry, and dissolution rate analysis. The degree of crystallinity of the drugs in solid dispersions decreased with decreases in the molar ratio of the drugs to lactose. Fourier-transform infrared (FT-IR) analysis demonstrated the presence of intermolecular hydrogen bonds between the primary amide group of carbamazepine and lactose. Dissolution studies indicated that the dissolution rate was markedly increased in solid dispersions compared with physical mixtures and pure drugs. These results indicated that lactose is useful as a carrier for the production of solid dispersions of drugs having a primary amide group in their structures.

Calorimetry, Differential Scanning↗

Synthesis of some pseudo-peptide analogs of thiol proteinase inhibitors.

Some pseudo-peptide analogs of thiol proteinase inhibitors were synthesized by a conventional solution method. Among them, Suc-Ala-Val-Val-Ala-psi-(CH2-NH)-Ala-pNA (peptide 1) and Suc-Ala-Val-Val-psi-(CH2-NH)-Ala-Ala-pNA (peptide 2) showed a stronger inhibitory activity compared with parent peptide such as Suc-Ala-Val-Val-Ala-Ala-pNA. In particular, peptide 2 was about 10-fold as active as the parent peptide (IC50 = 8 microM). Inserting psi-(CH2-NH) possibly makes the inhibitor less susceptible to papain and, as a result, produces more potent inhibition.

Buffers↗

["The CD38-cyclic ADP-ribose signal system": molecular mechanism and biological significance].

Glucose induces an increase in the intracellular Ca2+ concentration in pancreatic beta-cells to secrete insulin. CD38 exists in beta-cells and has both ADP-ribosyl cyclase, which catalyzes the formation of cyclic ADP-ribose (cADPR) from NAD+, and cADPR hydrolase, which converts cADPR to ADP-ribose. ATP, produced by glucose metabolism, competes with cADPR for the binding site, Lys-129, of CD38, resulting in the inhibition of the hydrolysis of cADPR and thereby causing cADPR accumulation in beta-cells. cADPR then binds to FK506-binding protein 12.6 (FKBP 12.6) in the islet type of the ryanodine receptor (RyR), dissociating the binding protein from RyR to induce the release of Ca2+ from the endoplasmic reticulum. Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) phosphorylates RyR to sensitize and activate the Ca2+ channel. Ca2+, released from the RyR, further activates CaM kinase II and amplifies this process. Thus, cADPR acts as a second messenger for Ca2+ mobilization to secrete insulin. The novel mechanism of insulin secretion described above is different from the conventional hypothesis in which Ca2+ influx from extracellular sources plays a role in insulin secretion by glucose. Furthermore, many physiological and pathological phenomena in various tissues and cells such as cardiac muscles, cerebellum, neuronal cells, pancreatic acinar cells, alveolar macrophages and immune B-cells become understandable in terms of "the CD38-cADPR signaling system" that sometimes acts in cooperation with other signal systems.

ADP-ribosyl Cyclase↗