The in vitro pharmacological profile of KR31080, a nonpeptide AT1 receptor antagonist

Summary— KR31080 (2-butyl-5-methyl-6-(1-oxopyridin-2-yl)-3-[[2'-(1H-tetrazol-5-yl) biphenyl-4-yl]methyl]-3H-imidazo[4,5-b] pyridine) is a potent inhibitor of angiotensin type 1 (AT₁) receptors in rabbit aorta and human recombinant AT₁ receptors. In the isolated rabbit thoracic aorta, KR31080 caused a nonparallel shift to the right of the concentration-response curves to angiotensin II (All) with decreased maximal response (pD'₂ = 10.1 ± 0.1), but had no effect on the contractile response induced by norepinephrine. KR31080 inhibited specific [¹²⁵I]AII binding to rabbit aortic membranes (AT, receptors) and [¹²⁵I][Sar¹, Ile⁸]AII binding to human recombinant AT₁ receptors in a concentration-dependent manner with IC₅₀ values of 0.84 ± 0.08 nM and 1.92 ± 0.15 nM, respectively, but did not inhibit specific [¹²⁵I)AII binding to bovine cerebellum membranes (ÀT₂ receptors). In the Scatchard analysis, KR31080 interacted with rabbit aortic AT₁ receptors in a competitive manner, similar to losartan. These results demonstrate that KR31080 is a potent and AT₁ selective angiotensin receptor antagonist which exerts a competitive antagonism in the [¹²⁵I]AII binding assay and insurmountable AT₁ receptor antagonism in the functional study.     

Phase II trial of 10 deaza-aminopterin in patients with bladder cancer

Summary Deaza-aminopterin is a folate analog which is transported more rapidly than methotrexate into cells and appears to be more active than methotrexate against human and animal tumor in vitro. Fifteen patients with advanced urothelial tract cancer were given deaza-aminopterin 30–37.5 mg/m² IV QW. In responding patients drug was given QOW after 4–6 consecutive doses. Doses were escalated or de-escalated by 7.5 mg/m² depending on toxicity. Twelve patients had received prior chemotherapy which included methotrexate in nine. Three patients achieved a partial remission lasting 1, 3, and 3 months respectively: all responders had previously failed methotrexate after an initial response to a methotrexate containing regimen. None of the six patients who were methotrexate naive responded to deaza-aminopterin; 3 subsequently received methotrexate without response. Mild mucositis was universal and in 5 was severe. Six patients had an increase in liver transaminases probably secondary to anti-folate hepatotoxicity. Other toxicities included diarrhea, nausea, skin rash and fever. Further studies are needed to define the precise efficacy of deaza-aminopterin in patients with urothelial tract cancers.     

Phase II trial of Didemnin B in patients with advanced renal cell carcinoma

Summary Twenty-three patients with advanced renal cell cancer were treated with Didemnin B. One partial response was achieved (5%) in 21 evaluable patients. An allergic reaction was noted in four patients including one patient with anaphylaxis. Didemnin B is not recommended in the treatment of renal cell carcinoma.     

Ictal and Interictal Electrographic Seizure Durations in Preterm and Term Neonates

Summary: The effect of gestational age on neonatal ictal and interictal durations has not been investigated. Sixty-eight neonates with 644 electrographic seizures were identified retrospectively. Thirty-five full-term (FT) neonates were compared with 33 preterm (PT) neonates. Eighteen older preterm infants (OPT) [>31 weeks estimated gestational age (EGA)] were also compared with 15 young preterm infants (YPT) of ≤31 weeks EGA. Ictal/ interictal durations were calculated for the total cohort with and without status epilepticus (SE). Statistical analyses were two-tailed t tests, chi-square calculations, and one-way analysis of variance (ANOVA) with Duncan's multiple-range test. Eleven of 35 (33%) FT had SE as compared with 3 of 33 (9%) PT (chi-square = 7.8, p < 0.05). The mean ictal duration was 14.2 min for FT infants as compared with 3.1 min for PT infants (p < 0.01); only borderline differences were noted after those with SE were excluded. Interictal durations were longer for OPT than YPT (p < 0.05). By ANOVA and Duncan's multiple-range tests, group differences included longer mean ictal durations for FT infants as compared with OPT infants (p = 0.06, ANOVA; p < 0.05, Duncan's), and longer mean interictal durations for FT infants versus OPT and OPT versus YPT (p = 0.02, ANOVA; p < 0.05, Duncan's). More developed neuronal networks result in longer ictal durations in FT than in PT neonates, including FT infants with SE. Inhibitory networks responsible for longer interictal periods are more dominant in OPT infants than in YPT infants, reflecting maturational changes that suppress seizure activity during the latter part of the third trimester before the infant reaches an FT corrected age.     

Complications of biliary surgery

Procedures on the gallbladder and extrahepatic biliary tract were the most frequently performed operations in a series of 1500 consecutive abdominal operations done in community hospitals. The operative mortality rate for elective cholecystectomy was 0.3 per cent. The complication rate was 21.4 per cent for cholecystectomy. Patients requiring emergency cholecystectomy had significantly more urinary tract and intra-abdominal problems than those patients who underwent surgery electively. Operative cholangiography was performed during 20.3 per cent of the elective cholecystectomies. There were no biliary tract complications among the cholecystectomy patients who had cholangiography. When this study was not performed, 1.5 per cent of the patients had postoperative bile duct problems. Older surgeons (greater than 60 years of age) and high volume surgeons (greater than 300 cases/year) were significantly less likely to employ cholangiography. The mortality rate for elective common duct exploration was 4.4 per cent, with a complication rate of 60 per cent. There was a 13.3 per cent incidence of retained stones after choledochotomy, though this problem was readily managed by percutaneous extraction through the T-tube tract. Complex biliary tract procedures were performed electively without mortality, though the complication rate for these procedures was 35.3 per cent. Two-thirds of the patients undergoing complex biliary tract operations on an emergency basis died. Board certified general surgeons had the same mortality and complication rates for cholecystectomy as well as common bile duct exploration. Noncertified surgeons had significantly more intraabdominal complications after complex biliary tract procedures compared to their board certified colleagues.     

LIPOPROTEIN(α) IN HEALTH AND DISEASE

SUMMARY Elevated plasma levels of Lp(a) do seem to influence the progression of atherosclerosis. Evidence is emerging that certain apo(a) isoforms may be more atherogenic than others, and in transgenic mice free apo(a) has been shown to be associated with accelerated atherosclerosis. Currently it is not known whether treating elevated Lp(a) levels will reduce progression of atherosclerosis and, as therapeutic options are limited, mass screening of Lp(a) levels in populations is not indicated. The presence of raised Lp(a) levels, however, warrants aggressive treatment to reduce other cardiovascular risk factors. Continuing research to investigate the relationship of the apo(a) gene to other genes, including the plasminogen gene and apo(a)-related genes, will add further information pertaining to the evolution, function, regulation and clinical implications of Lp(a).     

Detection of chromosomes and estimation of aneuploidy in human spermatozoa using fluorescence in-situ hybridization

The development and application of fluorescence in-situ hybridization (FISH) has opened the way for comprehensive studies on numerical chromosome abnormalities in human spermatozoa. FISH can be rapidly applied to large numbers of spermatozoa and thus overcomes the major limitation of karyotyping spermatozoa after penetration of zona-free hamster oocytes. The simultaneous hybridization of two or more chromosome-specific probes to spermatozoa and subsequent detection of the bound probes using different fluorescent detection systems enables two or more chromosomes to be localized simultaneously in the same spermatozoon and provides a technique for undertaking reasonable estimates of aneuploidy. The most commonly used probes are those which bind to the centromeric region of specific chromosomes. Most studies to date have concentrated on estimating aneuploidy in spermatozoa from normospermic men, although reports are beginning to appear on aneuploidy in spermatozoa from subfertile and infertile men. Multi- probe FISH studies have generally reported disomy (hyperhaploidy) estimates of 0.05-0.2% per chromosome. There is preliminary evidence that some chromosomes such as X, Y and 21 are predisposed towards higher rates of non-disjunction during spermatogenesis. There are also suggestions of inter-donor variability in aneuploidy frequencies for specific chromosomes, although this requires confirmation in larger studies. While FISH is clearly a powerful technique that has many applications in reproductive medicine, it must also be realized that it does have limitations and the technology itself is still evolving and has yet to be fully validated on spermatozoa.      

Sequencing of the alpha-synuclein gene in a large series of cases of familial Parkinson's disease fails to reveal any further mutations. The European Consortium on Genetic Susceptibility in Parkinson's Disease (GSPD)

A mutation in exon 4 of the human alpha-synuclein gene was reported recently in four families with autosomal dominant Parkinson's disease (PD). In order to examine whether mutations in this exon or elsewhere in the gene are common in familial PD, all seven exons of the alpha- synuclein gene were amplified by PCR from index cases of 30 European and American Caucasian kindreds affected with autosomal dominant PD. Each product was sequenced directly and examined for mutations in the open reading frame. No mutations were found in any of the samples examined. We conclude that the A53T change described in the alpha- synuclein gene is a rare cause of PD or may even be a rare variant. Mutations in the regulatory or intronic regions of the gene were not excluded by this study.