Pilot study of prescription-event monitoring in Japan comparing troglitazone with alternative oral hypoglycemics.

OBJECTIVE: To examine adverse events reported in a pilot study of the prescription-event monitoring in Japan (J-PEM) scheme, comparing troglitazone with other oral hypoglycemics. METHODS: We used a cohort study with a concurrent control in which information was gathered from both doctors and pharmacists. Crude event rates were calculated and compared between troglitazone (T) and alternative oral hypoglycemics (control drugs, C) using the likelihood ratio test. When the difference was statistically significant, possible confounding mechanisms were examined using Poisson regression analysis. RESULTS: Of 3,115 patient codes registered, pharmacists were sent 2,078 questionnaires and returned 1,814 (87%), while doctors were sent 1,858 questionnaires and returned 671 (36%). The difference in crude rates was statistically significant in 11 events (seven where T > C and four where C > T) reported by pharmacists and ten events (three where T > C and seven where C > T) reported by doctors. Among those, in two events, "weight increased" (T > C) and "abnormal hepatic function" (T > C), significant differences were observed in data from both doctors and pharmacists. Regression analysis revealed that the difference in crude rates for "nausea" (T > C) was possibly due to an uneven distribution of genders and that for "weight increased" (T >C) was possibly due to an uneven distribution of compliance. Patients with hepatic function abnormalities associated with troglitazone could be divided into two subtypes: one with a slight increase in serum lactate dehydrogenase concentration only and the other with elevated serum alanine aminotransferase. CONCLUSIONS: Comparison of the event rates between troglitazone and control drugs, followed by regression analysis, revealed several features of adverse events associated with drugs, including possible confounding mechanisms. Troglitazone-induced hepatic function abnormalities may be divided into two subtypes.

Drug use investigation (DUI) and prescription-event monitoring in Japan (J-PEM).

OBJECTIVE: To present ethical issues and relevant problems in observational studies of drug safety in Japan. METHODS: The Pharmaceutical Affairs Law, associated ordinances, and notifications relevant to Drug Use Investigations (DUIs), and published documents for two pilot studies of prescription-event monitoring in Japan (J-PEM) were examined, particularly with regard to the protection of privacy. Information relevant to the proposed legislation intended to protect personal information and proposed guidelines on ethical issues in epidemiological studies were also collected. RESULTS AND CONCLUSION: The formal studies inaugurated as the 'side-effect investigations' in the late 1960s and replaced by those of the DUI in 1980 have been conducted by drug manufacturers, in accordance with the Pharmaceutical Affairs Law. The first pilot study of J-PEM was started in 1997 and the second one is currently operated under a Health Sciences Research grant, supported by the Ministry of Health and Welfare. Those observational studies have been conducted while maintaining the confidentiality of personal data, but without requiring either approval by institutional ethics boards or informed consent from patients. However, according to the Pharmaceutical Affairs Law, those involved in postmarketing surveillance studies must protect the privacy of study subjects and those who break this rule may be subject to penalties. Ethical issues associated with pharmacoepidemiological studies will be clearly determined in Japan before the end of 2001 when the law designed to protect personal information will be introduced and official guidelines on ethical issues in epidemiological studies will have come into effect.

Transcriptional inhibition of the operon for the spermidine uptake system by the substrate-binding protein PotD.

Inhibition of spermidine uptake in Escherichia coli, which occurs in the presence of accumulated polyamines, has been studied using the spermidine uptake operon consisting of the potA, -B, -C, and -D genes. Transcription of the potABCD operon was inhibited by PotD, a spermidine-binding protein usually found in the periplasm, and the inhibitory effect of PotD was increased by spermidine. Transcription was not affected by bovine serum albumin, PotA, or PotF, suggesting that the effects of PotD are specific to the PotD protein. In the presence of 8 mM spermidine, a 50% inhibition of transcription was observed with a molar ratio of approximately 1:500 of template DNA:PotD. It was found that PotD bound to regions -258 to -209 nucleotides upstream and +66 to +135 nucleotides downstream of the ATG initiation codon of the potA gene. Binding of PotD to the downstream site was stimulated by spermidine. Overexpression of PotD in Escherichia coli DH5alpha inhibited the uptake of spermidine, the synthesis of PotABCD mRNA, and expression of a lacZ reporter gene fused downstream of a potA gene containing the PotD binding sites. In cells overexpressing PotD, a large amount of PotD existed as PotD precursor in spheroplasts. Our results indicate that PotD precursor can also inhibit spermidine transport. The amino acid residues in PotD that are involved in its interaction with the potABCD operon were determined using mutated PotD proteins. Thr-35 and Ser-85 of PotD were found to be important for this interaction. These results suggest that transcription of the spermidine transport (potABCD) operon is inhibited in vivo by PotD precursor rather than PotD through its binding to two regions close to the transcriptional initiation site of the operon.