A new polymorphism in exon 7 of the cystic fibrosis transmembrane regulator (CFTR) gene

Here we describe a new polymorphism, located in exon 7 of the cystic fibrosis transmembrane regulator (CFTR) gene at nucleotide position 1104 (CG), detected by single-strand conformational polymorphism (SSCP) analysis.     

Synthesis and intramolecular reactions of Tyr-Gly and Tyr-Gly-Gly related 6-O-glucopyranose esters

6-O-(L-Tyrosylglycyl)- and 6-O-(L-tyrosylglycylglycyl)-D-glucopyranose were synthesized by condensation of the pentachlorophenyl esters of the respective di- and tripeptide with fully unprotected D-glucose. The intramolecular reactivity of the sugar conjugates was studied in pyridine-acetic acid and in dry methanol, at various temperatures and for various incubation times. The composition of the incubation mixtures was monitored by a reversed-phase HPLC method that permits simultaneous analysis of the disappearance of the starting material and the appearance of rearrangement and degradation products. To determine the influence of esterification of the peptide carboxy group on its amino group reactivity, parallel experiments were done in which free peptides were, under identical reaction conditions, incubated with D-glucose (molar ratios 1:1 and 1:5). Depending on the starting compound, different types of Amadori products (cyclic and bicyclic form), methyl ester of peptides, and Tyr-Gly-diketopiperazine were obtained.     

Oncogenic Ras promotes butyrate-induced apoptosis through inhibition of gelsolin expression

Activation of Ras promotes oncogenesis by altering a multiple of cellular processes, such as cell cycle progression, differentiation, and apoptosis. Oncogenic Ras can either promote or inhibit apoptosis, depending on the cell type and the nature of the apoptotic stimuli. The response of normal and transformed colonic epithelial cells to the short chain fatty acid butyrate, a physiological regulator of epithelial cell maturation, is also divergent: normal epithelial cells proliferate, and transformed cells undergo apoptosis in response to butyrate. To investigate the role of k-ras mutations in butyrate-induced apoptosis, we utilized HCT116 cells, which harbor an oncogenic k-ras mutation and two isogenic clones with targeted inactivation of the mutant k-ras allele, Hkh2, and Hke-3. We demonstrated that the targeted deletion of the mutant k-ras allele is sufficient to protect epithelial cells from butyrate-induced apoptosis. Consistent with this, we showed that apigenin, a dietary flavonoid that has been shown to inhibit Ras signaling and to reverse transformation of cancer cell lines, prevented butyrate-induced apoptosis in HCT116 cells. To investigate the mechanism whereby activated k-ras sensitizes colonic cells to butyrate, we performed a genome-wide analysis of Ras target genes in the isogenic cell lines HCT116, Hkh2, and Hke-3. The gene exhibiting the greatest down-regulation by the activating k-ras mutation was gelsolin, an actin-binding protein whose expression is frequently reduced or absent in colorectal cancer cell lines and primary tumors. We demonstrated that silencing of gelsolin expression by small interfering RNA sensitized cells to butyrate-induced apoptosis through amplification of the activation of caspase-9 and caspase-7. These data therefore demonstrate that gelsolin protects cells from butyrate-induced apoptosis and suggest that Ras promotes apoptosis, at least in part, through its ability to down-regulate the expression of gelsolin.     

Phytoseiid mites in protected crops: the effect of humidity and food availability on egg hatch and adult life span of Iphiseius degenerans, Neoseiulus cucumeris, N. californicus and Phytoseiulus persimilis (Acari: Phytoseiidae)

The effect of relative humidity on egg hatch success for Iphiseius degenerans, Neoseiulus californicus and N. cucumeris was described by a binomial model with a parallel slope. The shape of the response differed for Phytoseiulus persimilis and a model with separate parameters gave a significantly better fit. Fitted response curves showed that I. degenerans, N. cucumeris, N. californicus and P. persimilis were ranked by decreasing tolerance to low humidity, with egg mortalities of < 0.5, 3, 12 and 16% respectively at 75-80% RH at 20 degrees C. Egg stage duration for I. degenerans and N. cucumeris was unaffected over the range 60-82% RH. For N. californicus and P. persimilis egg duration was significantly longer at 60 and 70% than for either 82 or 90% RH. No effect of relative humidity was found on the mean life span of adult females when food was available continuously to the mites. N. californicus lived significantly longer (58 days after the first egg was laid) than the other species. No significant difference was observed in mean life span between adult females of I. degenerans and N. cucumeris (25 and 28 days respectively). The mean life span of adult female P. persimilis (19 days) was significantly shorter than the other species. In the absence of both food and water, the survival of adult female mites was reduced to 2-4 days. Survival time was at least doubled when free water was available in the absence of food. Mean survival of adult female mites with water but without food was 10 days for N. cucumeris, 18 days for N. californicus, 6 days for P. persimilis and 4 days for I. degenerans. Survival of adult female N. cucumeris and N. californicus was increased significantly, to 20 and 22 days respectively, when fungal hyphae were present along with water but in the absence of other food.     

Make love to forget: two cases of transient global amnesia triggered by sexual intercourse

Transient global amnesia (TGA) is characterized by a sudden onset and by a typical resolution within several hours. Several precipitating events have been proposed: physical exertion, emotional experiences, etc. The aim of this paper was to present two cases of TGA triggered by sexual intercourse and to suggest a possible mechanism for the development of TGA. In both patients, clinical examination revealed elevated blood pressure. Laboratory examinations and brain CTs were normal. EEG demonstrated diffuse dysrhythmia and slow spike-waves, respectively. SPECT revealed hypoperfusion in the left frontal and right medial temporal regions. Various explanations of the mechanism of TGA are discussed. Based on the observed hypoperfusion in the medial temporal regions, a new hypothesis is advanced, suggesting the possibility that TGA occurs due to a pathologically changed or less adaptable anterior chorioid artery, initially constricted by hypotension following a blood shift from the center towards periphery.     

Patients review: drug-induced movement disorders

Objective of this paper is to review drug-induced movement disorders (D-IMD) treated patients on Department of Neurology in University Hospital Osijek. We reviewed patients treated during 10 years period (from 1992 to 2002). Analysed group consisted of 14 patients. Reasons for hospitalisation were swallowing problems in 6 patients, neuroleptic malignant syndrome (NMS) in 3 patients, stroke in 2 patients, bolus choking in 2 patients, and speech disturbance in 1 patient. Working diagnosis for most of our patients was neurological disease, yet only later D-IMD diagnosis was established excluding primary neurological disease, or as associated disease to basic neurological disorder. Nine patients have diagnosed as Parkinson syndrome, 3 patients as NMS, and 4 as orolingual dyskinesia, either autonomously, or in combination with Parkinson syndrome. D-IMD was most frequently caused by neuroleptics. Thus the small number of patients hospitalised regarding this syndrome on Department of Neurology.     

ULTRASTRUCTURE OF THE SECONDARY PHLOEM OF TILIA AMERICANA

Summer and winter (July and January) samples of secondary phloem of Tilia americana were studied with the electron microscope. Parenchyma cells contain: nuclei, endoplasmic reticulum, ribosomes, plastids, mitochondria and occasional dictyosomes. Well-defined tonoplasts separate vacuoles from cytoplasmic ground substance. Vacuoles often contain tannins. Lipid droplets are common in cytoplasm. Endoplasmic reticulum–connected plasmodesmata are aggregated in primary pit fields. Companion cells differ from parenchyma cells in having numerous sieve-element connections, possibly slime, and in lacking plastids. Mature, enucleate sieve elements possess 1–4 extruded nucleoli. Numerous vesicles occupy a mostly parietal position in association with plasmalemma. The mature sieve element lacks endoplasmic reticulum, organelles (except for few mitochondria) and tonoplast. In OsO_4– and glutaraldehyde-fixed elements, slime has a fine, fibrillar appearance. Normally, these fine fibrils are organized into coarser ones which form strands that traverse the cell and the plasmalemma-lined pores of sieve plates and lateral sieve areas.     

Hepatoprotective effects of melatonin against pronecrotic cellular events in streptozotocin-induced diabetic rats

Oxidative stress-mediated damage to liver tissue underlies the pathological alterations in liver morphology and function that are observed in diabetes. We examined the effects of the antioxidant action of melatonin against necrosis-inducing DNA damage in hepatocytes of streptozotocin (STZ)-induced diabetic rats. Daily administration of melatonin (0.2 mg/kg) was initiated 3 days before diabetes induction and maintained for 4 weeks. Melatonin-treated diabetic rats exhibited improved markers of liver injury (P?<?0.05), alkaline phosphatase, and alanine and aspartate aminotransferases. Melatonin prevented the diabetes-related morphological deterioration of hepatocytes, DNA damage (P?<?0.05), and hepatocellular necrosis. The improvement was due to containment of the pronecrotic oxygen radical load, observed as inhibition (P?<?0.05) of the diabetes-induced rise in lipid peroxidation and hydrogen peroxide increase in the liver. This was accompanied by improved necrotic markers of cellular damage: a significant reduction in cleavage of the DNA repair enzyme poly(ADP-ribose) polymerase 1 (PARP-1) into necrotic 55- and 62-kDa fragments, and inhibition of nucleus-to-cytoplasm translocation and accumulation in the serum of the high-mobility group box 1 (HMGB1) protein. We conclude that melatonin is hepatoprotective in diabetes. It reduces extensive DNA damage and resulting necrotic processes. Melatonin application could thus present a viable therapeutic option in the management of diabetes-induced liver injury.     

Microsatellite inferred genetic diversity and structure of Western Balkan grapevines (Vitis vinifera L.)

A collection of 196 grapevine samples from five countries of the Western Balkan region, representing local and traditional cultivars, was genotyped with 22 SSR markers. Identity analysis revealed 125 unique genotypes, which were further used for diversity assessment. The average number of alleles per locus detected was 11?±?3.53, ranging from 6 to 21. The low cumulative probability of identical genotypes (2.96?×?10^?20) shown in this study implies an even distribution of alleles within the analyzed set of grapevines and a sufficient number of loci. On the basis of the discriminatory power of each SSR, a set of five markers (VVMD5, VVMD7, VVMD28, VChr3a, and VChr8b) was determined as sufficient for high-throughput discrimination of the target cultivars. The maximum discriminating power was evidenced for loci VVMD28 and Vchr8b (0.96, 0.94, respectively). A core collection covering the entire genetic diversity resulted in a set of 60 genotypes representing approximately 50 % of the samples from each country. Structure clustering of Balkan and West European cultivars resulted in four well distinct groups identified according to the classification of Negrul (1946). The lowest level of admixed genotypes was assigned for grapevines from Bosnia and Herzegovina (61 %) and the highest for Serbian (87 %) grapevines. In terms of grape use, the wine cultivars were divided into three groups and the fourth group was intermixed, with half wine and half table grapes. The highest Nei’s genetic distance (0.22) was discovered between Slovenian and Macedonian cultivars, while the lowest (0.09) was between Slovenian and Serbian cultivars. Macedonian cultivars were genetically most distant from the others (0.17). A similar pattern of differentiation among populations is seen with distance-based clustering. Analysis of molecular variance revealed only 1 % of genetic variation among groups of different origin, while the variation among individuals within geographical groups and within individuals explained 13 and 86 % of the total variation, respectively.