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Biomedical subjects

D Kobayashi

Publications and source records attributed to D Kobayashi.

At least 91 records · Page 5Linked to original sources
PubMed1994

Analysis of the combined effect of 1-menthol and ethanol as skin permeation enhancers based on a two-layer skin model.

The combined effects of 1-menthol and ethanol as a skin permeation enhancer were evaluated with two equations describing the permeability coefficient through full-thickness skin (PFT) and the full-thickness skin/vehicle concentration ratio (CFT/CV) of drugs as a function of their octanol/vehicle partition coefficient (KOV). A two-layer model was applied for skin, which consists of a stratum corneum (SC) with lipid and porous pathways and a viable epidermis and dermis (ED). The two equations contain one variable (KOV) and nine coefficients, six of which (three diffusion coefficients, the porosity of the SC, and two terms of the linear free energy relationship) were considered different, dependent on the drug vehicle. In vitro permeation of four drugs (morphine hydrochloride, atenolol, nifedipine, and vinpocetine) was determined using excised hairless rat skin and four aqueous vehicles (water, 5% 1-menthol, 40% ethanol, and 5% 1-menthol-40% ethanol) to measure each PFT. Drug concentrations in full-thickness skin were also measured to obtain CFT/CV. A nonlinear least-squares method was employed to determine six coefficients using the two equations and experimentally obtained PFT and CFT/CV. The addition of 1-menthol to water and 40% ethanol increased the diffusion coefficient of drugs in lipid and pore pathways of SC, whereas the addition of ethanol to water and 5% 1-menthol increased the drug solubility in the vehicle, decreased the skin polarity, and increased the contribution of the pore pathway to whole-skin permeation.

Animals↗
PubMed1994

Induction of synthesis of heat shock protein 72 in tumor necrosis factor gene-transduced cells.

Heat shock protein (HSP) and endogenous tumor necrosis factor (enTNF) both act as resistance factors against the cytotoxicity of various cellular stresses. To clarify the relationship between these two stress response systems, we investigated whether or not enTNF is capable of inducing HSP72. Without heating, no difference was found in HSP72 synthesis between enTNF-nonexpressing L-M cells and cells expressing L-R or L-M (pcDV-TNF). After initiation of heat treatment, however, a remarkable increase in HSP72 synthesis was noted in enTNF-expressing cells compared to enTNF-nonexpressing L-M cells. These findings indicated that enTNF augments heat-inducible HSP72 synthesis.

Animals↗
PubMed1993

Feasibility of use of several cardiovascular agents in transdermal therapeutic systems with l-menthol-ethanol system on hairless rat and human skin.

Effect of the simultaneous use of l-menthol and ethanol on the skin permeation of six potent cardiovascular agents: nicardipine hydrochloride, atenolol, captopril, nifedipine, vinpocetine and nilvadipine (in hydrophilic order) was investigated to evaluate the feasibility of their use in a transdermal therapeutic system (TTS). In vitro diffusion experiments were carried out using excised hairless rat and human skin, and the application area of TTS required for the minimum therapeutic effect was estimated by a simple pharmacokinetic calculation. Marked enhancing effect by the l-menthol-ethanol system was found independent of drug lipophilicity, but the mode of action was dependent on the lipophilicity of the drug. The action of the system on lipophilic drugs (nifedipine, vinpocetine and nilvadipine) was mainly due to their increase in solubility in the system, while that on hydrophilic (or water soluble) drugs (nicardipine hydrochloride, atenolol and captopril) was the result of increase in their skin permeability coefficient. This enhancing effect was adequate to assure their minimum effective concentration (MEC) in human. The area of application of a drug to maintain the MEC was calculated to be 0.15 cm2 for hydrophilic or water soluble drugs and 3.7-13 cm2 for lipophilic drugs.

Administration, Cutaneous↗
PubMed1993

Rupture of a giant renal artery aneurysm: report of a case.

We report a case of rupture of giant renal artery aneurysm (10 cm diameter) with lower abdominal discomfort and a syncopal attack. The patient was successfully treated by nephrectomy. Rupture of a giant renal artery aneurysm is lethal in most cases and prompt diagnosis is indispensable. As preoperative diagnosis, ultrasonography was useful as it showed the blood flow in the renal artery aneurysm in real-time. CT scan was also useful in determining accurately the size of the aneurysm and extension of hematoma in its surroundings.

Aneurysm, Ruptured↗
PubMed1993

[A case of renal cell carcinoma extending into renal vein in an 18-year-old male].

An 18-year-old male was admitted to our hospital because of massive gross hematuria. Ultrasound and computerized tomographic (CT) scan revealed a solid left intrarenal mass with renal pelvic invasion and tumor thrombus in the left renal vein. Radical nephrectomy with intravenous tumor thrombectomy was performed. The left kidney weighted 354 g. Histological diagnosis was renal cell carcinoma of the kidney. He received prophylactic injections of interferon-alpha at a daily dose of 3 million units 3 times a week for 3 months.

Adolescent↗
PubMed1992

Ventilatory effects of dexmedetomidine, atipamezole, and isoflurane in dogs.

Dexmedetomidine (DMED) is a novel alpha 2 adrenergic agonist that has been shown to have potent analgesic and anesthetic sparing effects. This study was designed to investigate the effects of DMED, both alone and combined with isoflurane, on resting ventilation, the hypercapnic response, and the hypoxic response in dogs. When given alone, 1 microgram/kg decreased resting ventilation by 22% but at larger doses (10, 20, and 100 micrograms/kg) resting ventilation increased, doubling at 100 micrograms/kg. Doses of 10 micrograms/kg and greater caused a maximum depression of 60% in the slope of the hypercapnic response, but no dose had a significant effect on the hypoxic ventilatory response. A dose of 3 micrograms/kg of DMED reduced isoflurane MAC from 1.3% to 0.37%, and the ventilatory effects of this 1 MAC combination were intermediate between the awake values and those of isoflurane-anesthetized (1.3%) dogs. Atipamezole is a specific centrally acting alpha 2 receptor antagonist and when given with DMED in isoflurane-anesthetized dogs prevented the ventilatory depression. However, atipamezole alone also ventilatory stimulating effects, which may indicate tonic alpha 2 adrenergic activity. The ventilatory depression caused by DMED, either alone or combined with isoflurane, at doses that significantly reduce anesthetic requirements are relatively mild.

Adrenergic alpha-Agonists↗
PubMed1992

[Clinical effect of Cernilton in chronic prostatitis].

Twenty-five patients with chronic prostatitis were given Cernilton tablets. Improvement of subjective symptoms and objective findings was noted in 96.0% and 76.0% of the cases. Sonographic findings in the prostate showed 33-100% improvement in four objective items. No side effects were observed in any case after Cernilton medication. Cernilton was judged to be an effective drug for chronic prostatitis.

Administration, Oral↗
PubMed1991

[Voiding disturbance in elderly males examined by prostate mass screening. Gunma Urological Oncology Study Group].

Information about voiding disturbance was obtained from 34,140 elderly males in Gunma Aged Club Association (Q group) through a questionnaire and from 8,129 males by prostate mass screening for prostate disease (MS group) as to: (1) the characteristics of the subjects examined by the mass screening, (2) the relationship between the voiding disturbance and aging and (3) the frequency of voiding disturbance in the normal elderly males. In MS group, the percentage of young subjects, especially less than 60 years old, who complained voiding disturbance was higher than the expected percentage on the assumption that it increases with aging. The percentage of voiding disturbance in these young subjects was also higher than that of males in the same decade in Q group. In their past and present history, the percentage of benign prostatic hypertrophy (BPH) in these young subjects was higher than the expected percentage on the assumption that the incidence of BPH increases with aging. Judging from these results, it was estimated that they were not satisfied with the medical care by which they were treated or were being treated, and they received this mass screening to obtain consultation for their complains. Loss of the force was related with the prostate size estimated by digital rectal examination but not with aging. However, nocturia was well related with aging but not with the prostate size. Hesitancy, strain and dribbling were not apparently related with either the prostate size or aging. It was demonstrated that frequency of nocturia was 0 to 1 in less than 60 years old normal males, 0 to 2 in 60 to 79 years old ones and 0 to 3 in over 80 years old ones. The other symptoms studied in each decade were also analyzed and discussed.

Aged↗
PubMed1990

Postoperative lumbar spinal instability occurring or progressing secondary to laminectomy.

The manifestations and pathomechanism of postoperative lumbar spinal instability, occurring or progressing secondary to laminectomy, was clarified by means of functional radiographic analysis in a series of 46 patients over 40 years of age. The relation between instability and the clinical symptoms also is discussed. In patients under 60 years of age, instability at the operated level tended to appear in cases of wide laminectomy more often than in cases of partial laminectomy. Occurrence or progress of instability seems to be promoted by resection of the posterior spinal elements rather than the disc. It is further considered that the postoperative aggravation of clinical symptoms may be influenced not only by instability, but also by the other factors.

Age Factors↗
PubMed1988

Improved broad-host-range plasmids for DNA cloning in gram-negative bacteria.

Improved broad-host-range plasmid vectors were constructed based on existing plasmids RSF1010 and RK404. The new plasmids pDSK509, pDSK519, and pRK415, have several additional cloning sites and improved antibiotic-resistance genes which facilitate subcloning and mobilization into various Gram-negative bacteria. Several new polylinker sites were added to the Escherichia coli plasmids pUC118 and pUC119, resulting in the new plasmids, pUC128 and pUC129. These plasmids facilitate the transfer of cloned DNA fragments to the broad-host-range vectors. Finally, the broad-host-range cosmid cloning vector pLAFR3 was improved by the addition of a double cos casette to generate the new plasmid, pLAFR5. This latter cosmid simplifies vector preparation and has permitted the rapid cloning of genomic DNA fragments generated with Sau3A. The resulting clones may be introduced into other Gram-negative bacteria by conjugation.

Amino Acid Sequence↗
PubMed1982

Antifungal action of amphotericin B in combination with other polyene or imidazole antibiotics.

We compared the in vitro antifungal action of amphotericin B (AmB) used alone or in combination with a second polyene antibiotic or with miconazole or ketoconazole. When AmB was used in combination with either filipin or Etruscomycin (Farmitalia, Milan, Italy), antagonism or potentiation of the antifungal effect against Candida albicans resulted. Addition of AmB to Etruscomycin- or filipin-treated cultures resulted in antagonism. In contrast, potentiation occurred when Etruscomycin or filipin was added to cultures treated with AmB. The outcome of incubating C. albicans with combinations of AmB and either miconazole or ketoconazole depended on the duration of exposure of the cells to the drugs. Short-term incubations resulted in antagonism, whereas potentiation of antifungal effects occurred after prolonged exposure of cells to the antibiotics. In addition, supplementation of cultures with serum protein-potentiated AmB induced k+ leakage at low protein concentrations and inhibited K+ leakage at high protein concentrations.

Amphotericin B↗
PubMedDate not supplied

Heat-induced apoptosis via caspase-3 activation in tumour cells carrying mutant p53.

Apoptosis plays an important role in heat-induced cell death. However, the mechanism of heat-induced apoptosis has not yet been elucidated. In the present study, the signal transduction pathway underlying heat-induced apoptosis was investigated in heat-resistant HeLa cells carrying mutant p53 gene and heat sensitive HeLa cells that had been transduced with an antisense TNF gene. Induction of mutant p53, but not p21/WAF-1, was observed after heat treatment of both the resistant and sensitive cells. Heat-induced cytotoxicity was not inhibited in either cells with interleukin-1beta-converting enzyme (ICE: caspase-1) like protease inhibitor Ac-YVAD-CHO. In contrast, there was 48% and 63% inhibition of cytotoxicity in HeLa and transfectants, respectively, with a caspase-3 inhibitor (Ac-DEVD-CHO). Heat-induced apoptosis was also prevented by administration of Ac-DEVD-CHO in both cells. In addition, an augmentation of heat-induced cytotoxicity in transfectants was almost completely inhibited by Ac-DEVD-CHO. Further, caspase-3 mRNA expression was increased remarkably in heat-treated HeLa cells and transfectants. Taken together, these results suggest that activation of caspase-3 is involved in the signal transduction pathway of heat-induced apoptosis of the tumour cells carrying mutant p53.

Base Sequence↗
PubMedDate not supplied

Endogenous tumor necrosis factor functions as a resistant factor against hyperthermic cytotoxicity in pancreatic carcinoma cells via enhancement of the heart shock element-binding activity of heart shock factor 1.

To elucidate the relationship between two distinct resistant factors, endogenous tumor necrosis factor (enTNF) and heat shock proteins (HSPs), against hyperthermia, we assessed whether enTNF enhances HSP72 expression. Although there was a variability in the sensitivity of pancreatic carcinoma cell lines to heat, enTNF and HSP72 expression as well as MnSOD activity correlated positively with heat resistance. When MIAPaCa-2 pancreatic carcinoma cells, which had the lowest enTNF expression and highest heat sensitivity, were transfected with a nonsecretory-human TNF gene (pTNF delta pro), intracellular manganous superoxide dismutase (MnSOD) activity, HSP72 expression, and heat resistance were significantly increased. Furthermore, in these cells, enTNF expression correlated with the binding activity of heat shock factor 1 (HSF 1) to an oligonucleotide containing the human heat shock element. These results indicate that enTNF participates in the intrinsic resistance against heat via induction of MnSOD, enhances HSF1-binding activity, and augments of HSP72 expression. Therefore, inhibition of enTNF expression in pancreatic carcinoma cells would improve the efficacy of hyperthermia for pancreatic carcinoma.

DNA-Binding Proteins↗
PubMedDate not supplied

Protein kinase C inhibitors augment tumor-necrosis-factor-induced apoptosis in normal human diploid cells.

In this report we show augmentation of tumor necrosis factor (TNF)-induced apoptosis by protein kinase C (PKC) inhibitors in human embryonic lung fibroblast (HEL) cells. Staurosporine (STS) reportedly potentiates TNF-mediated cytotoxicity in cancer cell lines via inhibition of PKC. We investigated whether STS or another potent PKC inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H7), augmented TNF-induced apoptosis in normal human diploid cells and examined the effects of the PKC inhibitors on the expression of endogenous TNF (enTNF) and manganous superoxide dismutase (MnSOD) as possible cell resistance factors opposing TNF-induced apoptosis. Both PKC inhibitors augmented TNF-mediated DNA fragmentation in HEL cells, which are normally TNF resistant and constitutively express high amounts of enTNF and MnSOD activity. Neither the number nor the affinity of TNF receptors were altered by STS and H7. The expression of enTNF and MnSOD was suppressed by the presence of STS or H7 along with TNF. The results indicate that PKC inhibitors augment TNF-induced apoptosis not only in tumor cells but also in normal cells by inhibitory effects on cellular resistance factors such as enTNF and MnSOD.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗