Takashi Ishihara

Serum growth hormone-binding protein, insulin-like growth factor-I, and growth hormone in patients with liver cirrhosis.

We determined serum growth hormone-binding protein (GHBP), insulin-like growth factor-I (IGF-I), and growth hormone (GH) levels in patients with cirrhosis and in age-matched control subjects, and investigated their relationships. Serum GHBP levels in cirrhotic patients (14.6% +/- 3.9%) (means +/- SD) were significantly lower than those in normal subjects (20.4% +/- 4.7%). GHBP levels had positive correlations with cholinesterase (r = .58, P less than .001) and Normotest (r = .66, P less than .001), both of which represent liver function in cirrhotic patients. Basal GH levels in cirrhotic patients (range, 0.35 to 13.0 micrograms/L; median, 3.9 micrograms/L) were significantly higher than those in normal subjects (0.015 to 6.0 micrograms/L; 0.19 microgram/L). GHBP levels in cirrhotic patients correlated positively with IGF-I levels (r = .39, P less than .01), and negatively with GH levels (r = -.33, P less than .01). These results may indicate that the serum GHBP level reflects the number of hepatic GH receptors, and that the high basal GH level observed in cirrhotic patients is, at least in part, attributable to decreased clearance of GH by these receptors.

A convenient synthesis of 2,2-difluoro enol silyl ethers from chlorodifluoromethyl ketones

Abstract Various chlorodifluoromethyl ketones can be converted to the corresponding 2,2-difluoro enol silyl ethers in good yields, by the action of zinc dust and chlorotrimethylsilane in dry acetonitrile at 60°C.

Zinc-copper(I) chloride or -silver(I) acetate promoted aldol reaction of chlorodifluoromethyl ketones with carbonyl compounds. A general and effective route to α,α-difuluoro-β-hydroxy ketones

Abstract Chlorodifluoromethyl ketones efficiently underwent the aldol reaction with a variety of aldehydes or ketones in the presence of zinc, a catalytic amount of copper(I) chloride or silver(I) acetate and molecular sieves to give the corresponding α,α-difluoro-β-hydroxy ketones in good to excellent yields.

Macroprolactinaemia: prevalence and aetiologies in a large group of hospital workers

Objectiveu2002 Macroprolactinaemia is one of the causes of hyperprolactinaemia and often leads to misdiagnosis and inappropriate treatment, but the aetiologies are unclear. The objective of the study was to determine the prevalence of macroprolactinaemia in a healthy population and to investigate the mechanisms underlying the development of macroprolactin.

Organocuprate-induced substitution of the enol oxygen moiety in 2,2-difluoro enol phosphates with allyl halides: a novel route to gem-diffluoroolefins from chlorodifluoromethyl ketones☆

Abstract 2,2-Difluoro-1-arylethenyl diphenyl phosphates, prepared from chloro-difluoromethyl ketones and diphenyl phosphite, reacted with dibutylcopperlithium and successively with various allyl halides to give allylated gem -difluoroolefins in moderate to excellent yields.

Novel synthesis of F-1-alkene-1-phosphonate derivatives from F-alkanoyl chlorides and their efficient use for preparing fluoro-ga,β-enones

Abstract ( Z )-1-[(diethoxyphosphinyl)oxy]- F -1-alkene-1-phosphonates were synthesized in good yields from F -alkanoyl chlorides and triethyl phosphite, and were proved to be useful precursors for the preparation of fluoro-α,β-enones.

Addition reactions of F-alkyl iodides to carbon-carbon double bonds promoted by metallic tin(0)-metal salt systems

Abstract F -alkyl iodides readily reacted with a variety of alkenes in methanol at room temperature under the influence of metallic tin(0)-silver(I) acetate of metallic tin(0)-copper(I) chloride to afford the corresponding addition products, F - alkylated iodides, in good to excellent yields. This addition reaction was also promoted by the use of a metallic tin(0)- aluminium(0) reagent, though gentle heating was necessary for allowing the reaction to proceed.

Regiospecific α-hexafluoroisopropylidenation of ketones using hexafluoroacetone

Abstract Hexafluoroacetone (HFA) reacted regiospecifically with various enol silyl ethers at −30 to −35°C in the presence of a Lewis acid to give HFA aldols, or α-bis(trifluoromethyl)hydroxymethyl carbonyl compounds, in good yields. The reaction of HFA with dienol silyl ethers, on the other hand, cleanly proceeded even in the absence of a Lewis acid to provide [4+2]cycloadducts, or bistrifluoromethylated tetrahydropyran-4-one derivatives, quantitatively. The former HFA aldols were converted in excellent yields into α-hexafluoroisopropylidene ketones by the action of methyl chlorosulfite and pyridine.

Anti‐prolactin (PRL) autoantibodies suppress PRL bioactivity in patients with macroprolactinaemia

Objectiveu2002 Macroprolactinaemia, mainly caused by anti‐prolactin (PRL) autoantibodies, is frequently found in patients with hyperprolactinaemia. Characteristically, these patients lack clinical symptoms of hyperprolactinaemia, but the serum bioactive PRL concentrations in vitro measured by the Nb2 bioassay are usually high. In this study, we investigated the causes of the discrepancy and the true biological features of macroprolactin.

Zinc-copper(I) chloride or -silver acetate promoted coupling reaction of 2-[(Trimethylsilyl)methyl]-3-chloro-3,3-difluoropropene with carbonyl compounds. Highly efficient access to 2,2-difluoro homoallyl alcohols

Abstract 2-[(Trimethylsilyl)methyl]-3-chloro-3,3-difluoropropene, readily prepared in two steps from methyl chlorodifluoroacetate and (trimethylsilyl)methylmagnesium chloride, is reduced to couple regioselectivity with a variety of carbonyl compounds in the presence of zinc-copper(I) chloride or -silver acetate to give 2,2-difluoro-3-[(trimethylsilyl)methyl]-3-buten-1-ol derivatives in good to excellent yields.