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.     

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.      

Preliminary observations on polar body extrusion and pronuclear formation in human oocytes using time-lapse video cinematography

In this study, we have used time-lapse video cinematography to study fertilization in 50 human oocytes that had undergone intracytoplasmic sperm injection (ICSI). Time-lapse recording commenced shortly after ICSI and proceeded for 17-20 h. Oocytes were cultured in an environmental chamber which was maintained under standard culture conditions. Overall, 38 oocytes (76%) were fertilized normally, and the fertilization rate and embryo quality were not significantly different from 487 sibling oocytes cultured in a conventional incubator. Normal fertilization followed a defined course of events, although the timing of these events varied markedly between oocytes. In 35 of the 38 fertilized oocytes (92%), there were circular waves of granulation within the ooplasm which had a periodicity of 20-53 min. The sperm head decondensed during this granulation phase. The second polar body was then extruded, and this was followed by the central formation of the male pronucleus. The female pronucleus formed in the cytoplasm adjacent to the second polar body at the same time as, or slightly after, the male pronucleus, and was subsequently drawn towards the male pronucleus until the two abutted. Both pronuclei then increased in size, the nucleoli moved around within the pronuclei and some nucleoli coalesced. During pronuclear growth, the organelles contracted from the cortex towards the centre of the oocyte, leaving a clear cortical zone. The oocyte decreased in diameter from 112 to 106 microm (P < 0.0001) during the course of the observation period. The female pronucleus was significantly smaller in diameter than the male pronucleus (24.1 and 22.4 microm respectively, P = 0.008) and contained fewer nucleoli (4.2 and 7.0 respectively, P < 0.0001). After time-lapse recording, oocytes were cultured for 48 h prior to embryo transfer or cryopreservation. Embryo quality was related to fertilization events and periodicity of the cytoplasmic wave, and it was found that good quality embryos arose from oocytes that had more uniform timing from injection to pronuclear abuttal and tended to have a longer cytoplasmic wave. In conclusion, we have shown that time-lapse video cinematography is an excellent tool for studying fertilization and early embryo development, and have demonstrated that human fertilization comprises numerous complex dynamic events.      

Changes of ovarian microvasculature in hCG stimulated rabbits. A scanning electron microscopic study of corrosion casts

The microvasculature of the ovarian cortex was studied by means of scanning electron microscopy of vascular corrosion casts in estrous and hCG stimulated rabbits in order to establish a better understanding of the structural as well as functional vascular changes which accompany the evolution of the luteofollicular complex. According to the various shape and size seven different morphological types of vascular plexuses corresponding respectively to antral follicles (Types 1-2), atretic follicles (Types 3-4), periovulatory follicles (Type 5), growing pseudopregnant corpora lutea (Type 6) and regressing pseudopregnant corpora lutea (Type 7) were identified. Growing to mature cycling type follicles (Types 1-2) showed a gradual enlargement and proliferation of the theca capillaries. These changes, associated with capillary hyper-permeabilization were observed in ovulatory and post-ovulatory follicles (Types 5), after hCG stimulation. The corpus luteum formation (Types 6) was accompanied by additional capillary dilatation, diffuse angiogenetic sprouts and organization of a more conspicuous venous drainage. The regression of the corpus luteum (Type 7) was characterized by the appearance of avascular areas within the glandular tissue and by regression of vascular dilatation. The atretic follicle (Types 3-4) wall showed large interruptions (avascular areas) and focal invasion of the central cavity by newly formed capillaries randomly arranged. The hCG stimulation did not affect consistently the atretic follicle microvasculature. The present observation shows that both thecal capillary vasodilatation and angiogenetic processes support the gradual increase of ovarian blood flow during follicle growth and corpora lutea formation and that microvascular changes of atretic follicles are possibly related to a type of inflammatory reaction since they seem to be a consequence rather than a primary cause of atresia.     

Overview and update on molecular testing in non-small cell lung carcinoma utilizing endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) samples

Lung carcinoma remains one of the most frequent and aggressive human neoplasms. Fortunately, in the last decades, the increasing knowledge of the molecular mechanisms leading to cancer development has allowed the use of targeted therapies with improvement of prognosis in many patients. Clinical management has also changed after the introduction of endobronchialultrasonographic bronchoscopy that allows a conservative staging of lung tumors, avoiding the need of mediastinoscopy for lymph node staging. Lung pathologists and cytopathologists are facing the challenge of giving the more comprehensive prognostic and predictive information with ever smaller tissue or cytological samples. The aim of this review is to summarize the molecular testing for non-small cell lung carcinoma and how pathologists can contribute to the patient's outcome with a conscious management of biological samples.     

Hemodynamic changes during continuous infusion with dobutamine in candidates for lung transplantation. Lung Transplantation Group

BACKGROUND: The aim of this study is to analyze the effects of dobutamine (DBT) on pulmonary and systemic hemodynamics and oxygenation in lung transplant candidates. METHODS: Forty-five patients (21M, 24F) to be introduced in waiting list for lung transplantation were studied (14 pulmonary fibrosis, 15 COPD, and 16 cystic fibrosis). They were studied awake, while spontaneously breathing in two different phases: baseline--O2 100%; DBT phase--O2 100% after 10 minutes of DBT continuous infusion (10 mcg/Kg/min). Blood gas samples and hemodynamic data were collected during right heart catheterization. Data were statistically analyzed with Student's "t" test and values for p < 0.05 were considered as significant. RESULTS: During DBT phase, a significant increase of cardiac output with a decreasing in systemic and pulmonary vascular resistance was observed. Since the fall in pulmonary vascular resistance (PVRI) was not proportional to the increase of cardiac output, mean pulmonary artery pressure and transpulmonary gradient increased. The prevalent role of vascular recruitment as mechanism in PVRI reduction during DBT is supported by the concomitant fall in PaO2/FiO2. This strongly suggests a worsening of regional Va/Qc due to an increased perfusion of poorly ventilated areas. CONCLUSIONS: DBT reduces PVRI through a recruitment of vessels due to an increase of pulmonary flow. Dobutamine has a favorable hemodynamic effect in mild-to-moderate pulmonary hypertension in lung transplant candidates.     

Obesity Surgery Poly-parametric Patient Auto-evaluation

A simple auto-evaluation sheet is presented for the proper assessment of the patient's condition after surgery. Stress is put not only on weight loss, but on other important factors as well.