石杉碱甲类似物的研究II.N-甲基吡啶酮石杉碱甲类似物的合成

石杉碱甲(1)是从中草药石杉属植物千层塔(Lycopodium serratum Thunb.)中分得的一种高效可逆的乙酰胆碱酯酶抑制剂,临床试验证实它对早老性痴呆症有显著疗效。本文报道N-甲基吡啶酮石杉碱甲类似物2和3的合成。2-甲氧基-5-甲氧羰基-11-亚甲基-5,9-甲撑环辛-7-烯并吡啶(9)在乙腈中用三甲基氯硅烷和碘化钠选择性脱保护以定量的产率得吡啶酮10,再用甲醇钠和碘甲烷甲基化得N-甲基吡啶酮11,11经碱性水解,Curtius重排和氨基的脱保护得N-甲基吡啶酮石杉碱甲类似物2。通过类似的途径从中间体2-甲氧基-5-甲氧羰基-7-甲基-11-酮-5,9-甲撑环辛-7-烯并吡啶(14)合成了类似物3。类似物2和3的乙酰胆碱酯酶抑制活性均低于天然石杉碱甲。     

Coeliac haemodynamic effects of endothelin-1, endothelin-3, proendothelin-1 [1-38] and proendothelin-3 [1-41] in conscious rats.

1. Conscious, chronically-instrumented, Long Evans rats were given bolus doses of endothelin-1, endothelin-3 (both at 0.01 and 0.1 nmol kg-1), proendothelin-1 [1-38] and proendothelin-3 [1-41] (both 0.1 and 1 nmol kg-1) in order to compare their effects on coeliac haemodynamics, because it has been reported that, in conscious dogs, endothelin-1 has paradoxical, prolonged hyperaemic vasodilator effects in this vascular bed. Measurements were made also of mesenteric and hindquarters haemodynamics for comparison. In a separate experiment, endothelin-1 (0.1 nmol kg-1) was given before and 20 min after the onset of an infusion of mecamylamine (50 mumol kg h-1) to ensure that the responses measured were not confounded by rapid reflex changes in autonomic activity. 2. None of the peptides caused any increases in coeliac flow or any sustained rises in coeliac vascular conductance, although such changes were clear-cut in the hindquarters vascular bed following the higher dose of endothelin-1 and endothelin-3. In animals treated with mecamylamine the regional haemodynamic effects of the higher dose endothelin-1 were not different from those in animals with intact baroreflexes. 3. Although the lower dose of both endothelin-1 and endothelin-3 caused less marked coeliac, than mesenteric vasoconstriction, this difference was not apparent with the higher dose of the peptides, or with proendothelin-1 [1-38]. However, proendothelin-3 [1-41] had less marked coeliac and hindquarters vasoconstrictor effects than proendothelin-1 [1-38], in spite of both peptides causing similar changes in mesenteric haemodynamics.(ABSTRACT TRUNCATED AT 250 WORDS)     

p53 mutation and protein accumulation during multistage human esophageal carcinogenesis.

Preinvasive lesions of squamous cell carcinoma are well defined morphologically and provide a model for multistage carcinogenesis. Since alterations in the p53 tumor suppressor gene occur frequently in invasive esophageal squamous cell carcinoma, we examined a set of preinvasive lesions to investigate the timing of p53 mutation. Surgically resected tissues from nine patients with esophageal squamous cell carcinoma contained precursor lesions which had not yet invaded normal tissues. Immunohistochemistry showed high levels of p53 protein in both preinvasive lesions and invasive carcinomas in six cases; sequence analysis of all invasive tumors identified p53 missense mutations in two cases. Preinvasive lesions from both tumors with mutations plus one wild-type tumor were microdissected and sequenced. In one patient there were different mutations in the invasive carcinoma (codon 282, CGGarg > TGGtrp) and a preinvasive lesion (codon 272, GTGval > T/GTGleu/val). In a second case, an invasive carcinoma had a mutation in codon 175 (CGCarg > CAChis), and adjacent preinvasive lesions contained a wild-type sequence. A carcinoma and preinvasive lesion from the third case contained high levels of protein and a wild-type DNA sequence. Therefore, p53 mutation may precede invasion in esophageal carcinogenesis, and multifocal esophageal neoplasms may arise from independent clones of transformed cells. The timing of p53 protein accumulation is favorable for an intermediate biomarker in multistage esophageal carcinogenesis.     

The relationship between the Bayley Scales of Infant Development and preschool gross motor and cognitive performance

Early identification of disabilities enables early intervention by occupational therapists and other health professionals. Because the number of children who can be seen in therapy is limited, it is important to be able to identify those infants most likely to have deficits at a later age. Therefore, it is necessary to study and understand the relationship between infants' scores on early developmental assessments and later developmental outcomes. The purpose of this study was to determine the extent to which scores on the Bayley Scales of Infant Development (BSID) during the first 2 years of life are related to motor and cognitive performance at 4 1/2 years for a sample of children identified at birth as biologically high risk. This retrospective study involved 70 children who were evaluated at corrected ages of 4 months, 1 year, 2 years, and 4 1/2 years. The 4-month BSID Mental and Motor Scale scores did not relate significantly to later cognitive motor performance. In contrast, the 12-month BSID Mental Scale scores related significantly to preschool scores on both the motor and cognitive measures. However, the 24-month BSID Mental Scale scores related significantly only to scores on the preschool cognitive measures. Though significant, these correlation coefficients had small magnitudes. Thus, therapists should be cautious about using BSID testing at 4 months, 1 year, and 2 years when attempting to predict later preschool performance.     

Inhibition of the haemodynamic effects of angiotensin II in conscious rats by AT2-receptor antagonists given after the AT1-receptor antagonist, EXP 3174.

1. Conscious, Long Evans rats (n = 10), chronically instrumented for the measurement of regional haemodynamics, were studied on 3 consecutive experimental days to assess responses to angiotensin II (AII) (125 pmol kg-1, i.v.) and noradrenaline (1 nmol kg-1, i.v.) in the absence and presence of the AT2-receptor antagonist, PD 123319 (10 mg kg-1, i.v.) (day 1), the AT1-receptor antagonist, EXP 3174 (1 mg kg-1, i.v.) (day 2), and PD 123319 (10 mg kg-1, i.v.) given 24 h after EXP 3174 (day 3). 2. In naive rats (day 1), PD 123319 did not antagonize the haemodynamic effects of AII or noradrenaline. EXP 3174 (day 2) caused a marked, prolonged blockade of the haemodynamic effects of AII but not those of noradrenaline. Twenty four h after administration of EXP 3174 (day 3) there was still significant attenuation of the haemodynamic effects of AII. However, administration of PD 123319 at this time caused a further inhibition (lasting 1 h) of the effects of AII but not those of noradrenaline. 3. An identical 3 day protocol was used in a separate group of rats (n = 6) in which the AT2-receptor antagonist, PD 123177, was given instead of PD 123319, and the results were essentially the same, i.e., PD 123177 significantly attenuated the haemodynamic effects of AII but only when given 24 h after EXP 3174.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparative study of roles of the lobus parolfactorius and intermediate medial hyperstriatum ventrale in memory formation in the chick brain.

Two discrete areas of the chick brain, the intermediate medial hyperstriatum ventrale (IMHV) and lobus parolfactorius (LPO), were found to have different functions during the formation of memory for a 1-trial peck-avoidance paradigm. Glutamate, ouabain, and emetine, known to disrupt short-, intermediate-, and long-term memory when injected into the IMHV, were injected into the cerebellum and LPO. All amnestic agents investigated produced amnesia when injected into the IMHV; only one of these agents produced amnesia when injected into the LPO, and none of the agents produced amnesia when injected into the cerebellum. The chick brain was also found to exhibit hemispheric asymmetries: The left IMHV and LPO were more sensitive to the amnestic agents than their corresponding right structure. From these data, hypotheses for the roles of these structures during memory are proposed.