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Volume 114, Issue 4
Displaying 1-7 of 7 articles from this issue
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Shougo TAKEUCHI, Takeshi OSUGI1999 Volume 114 Issue 4 Pages 205-211
Published: 1999
Released on J-STAGE: September 07, 2011
JOURNAL FREE ACCESSNevirapine (NVP) is a potent noncompetitive inhibitor of the reverse transcriptase enzyme, which is necessary for HIV replication. NVP selectively inhibits HIV-1 but not HIV-2 and any of the human DNA polymerases. NVP is active against ZDV-resistant HIV-1 and synergistic with nonnucleoside reverse transcriptase inhibitors. NVP has a favorable pharmacokinetic profile, becomes widely distributed throughout body tissues including the central nervous system, and is active in the adult at an oral dose of 200 mg administered twice daily after a 2 week lead-in dose of 200 mg/day due to its long elimination half life. Although the currently used protease inhibitors (PIs) may undergo more rapid rates of metabolism because NVP induces CYP3A, No dosage adjustments are required when NVP is taken in combination with PIs so far. When administered in triple combinations with antiretroviral agents, the antiviral effect of NVP has been profound and sustained in HIV-infected patients, particularly in naive patients to antiretroviral therapy. Resistance to NVP is rapid when given as monotherapy, but this is altered and made less clinically relevant when NVP is administered as a triple combination. NVP has a safety profile that does not overlap with other antiretroviral therapies, the most common treatment-limiting reaction being rash. It seems that NVP would be a very useful option in combination with antiretroviral agents.View full abstractDownload PDF (3865K) -
Masayuki OMOTE1999 Volume 114 Issue 4 Pages 213-218
Published: 1999
Released on J-STAGE: September 07, 2011
JOURNAL FREE ACCESSPenile erection follows relaxation of the corpus cavernosum in which nitric oxide (NO) released during sexual stimulation from non-adrenergic non-cholinergic nerve endings and from endothelial cells of the corpus cavernosum plays a crucial role. Sildenafil (VIAGRA™) selectively inhibited phosphodiesterase type 5 (PDE5) activity in the human corpus cavernosum and increased cGMP concentrations in the rabbit cavernosum in the presence of NO. Sildenafil enhanced the NO-dependent relaxation of the isolated human corpus cavernosum and the intracavernosal pressure in the anesthetized dog without affecting systemic blood pressure and heart rate. In the patients with erectile dysfunction, an orally administered sildenafil enhanced the penile rigidity during visual sexual stimulation. Sildenafil did not affect the phenylephrineinduced contraction of the isolated rabbit aorta, but enhanced the relaxant effect of glyceryl trinitrate. The pharmacodynamic interaction with glyceryl trinitrate was also observed in human studies where sildenafil potentiated the hypotensive effect of the nitrate. These results indicate that sildenafil, which enhances the physiological process of penile erection during sexual arousal, is a novel orally effective treatment for erectile dysfunction. It should be noted, however, that sildenafil enhanced the hypotensive effect of glyceryl trinitrate, as a result of inhibition of PDE5 in vascular smooth muscle. Therefore, administration of sildenafil to patients who are using nitrates and NO donors is contraindicated.View full abstractDownload PDF (1531K) -
Toshihide YOKOYAMA1999 Volume 114 Issue 4 Pages 219-226
Published: 1999
Released on J-STAGE: September 07, 2011
JOURNAL FREE ACCESSTropisetron is used as an anti-emetic agent against chemotherapy-induced nausea and vomiting. Tropisetron shows strong 5-HT3 antagonist and weak 5-HT4 antagonist activities in vitro. In the various animal models of vomiting including chemotherapy-or radiotherapy-induced emesis in the dog and ferret, tropisetron is reported to inhibit the emetic episodes. The potent anti-emetic activity of oral tropisetron rather than the i.p. administered drug suggests that it can act directly from the intestinal lumen as well as from the blood stream after its absorption. Moreover, the anti-emetic activity of tropisetron may involve the 5-HT4-receptor mechanism in addition to the 5-HT3-receptor mechanism. Tropisetron has several pharmacological activities other than anti-emesis such as the stimulation of the gastric emptying and the inhibition of the diarrhea, visceral pain and anxiety. These effects of tropisetron may contribute to the high clinical efficacy of tropisetron against chemotherapy-induced emesis.View full abstractDownload PDF (3263K) -
Yasuyuki FURUKAWA1999 Volume 114 Issue 4 Pages 227-231
Published: 1999
Released on J-STAGE: September 07, 2011
JOURNAL FREE ACCESSThe site of impulse origin in the right atrium is generally considered to be a single static locus within the sinoatrial (SA) node. However, it has been recognized that the pacemaker site may shift as a consequence of changes in physiological and pathological conditions. To determine the role of the atrial pacemaker complex including the superior pacemaker site, SA node and inferior pacemaker site quantitatively, we investigated atrial rate and the earliest activation region (EAR) from the isochronal activation sequence map by 48 unipolar electrodes and the mapping system. The epicardial activation sequence of the right atrium including the SA node region was obtained from the 48 electrodes, which were fixed to two flexible templatesmade of soft plastic plates. Using the mapping system, we found that (1) the EAR was shifted by the sympathetic or parasympathetic neural activity, (2) parasympathetic activity predominates over the sympathetic activity not only on heart rate, but also on the location of the EAR, and (3) the role of the inward Ca2+ current, hyperpolarization inward current and delayed rectifier K+ current, of the pacemaker cells distributed in the atrial pacemaker complex is different in the dog heart in situ.View full abstractDownload PDF (4933K) -
Youichi FUKUDA, Miwa SAWATA, Masataka WASHIZUKA, Raita HIGASHINO, Yosh ...1999 Volume 114 Issue 4 Pages 233-238
Published: 1999
Released on J-STAGE: September 07, 2011
JOURNAL FREE ACCESSThe effect of liver hydrolysate (LH) derived from bovine liver on rat liver regeneration after partial hepatectomy (PH) were investigated. Oral administration of LH increased rat liver weight dose-dependently at 24 h after PH. Hepatic ornithine decarboxylase (ODC) activity and proliferating cell nuclear antigen (PCNA) labeling index were measured in regenerating rat liver as markers of cell proliferation. ODC activities at 4 and 24 h after PH were significantly increased by LH administration. PCNA labeling index at 24 h after PH were also increased by LH administration. These results suggest that LH stimulates liver regeneration in partially hepatectomized rats.View full abstractDownload PDF (9310K) -
1999 Volume 114 Issue 4 Pages b49-b61
Published: 1999
Released on J-STAGE: September 07, 2011
JOURNAL FREE ACCESSDownload PDF (3271K) -
1999 Volume 114 Issue 4 Pages b62-b81
Published: 1999
Released on J-STAGE: September 07, 2011
JOURNAL FREE ACCESSDownload PDF (5133K)
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