Impaired response to insulin associated with protein kinase C in chronic fructose-induced hypertension

A fructose-enriched diet induces an increase in blood pressure associated with metabolic alterations in rats. Our hypothesis was that an increase in protein kinase C (PKC) activation, reported in the acute period of fructose overload, and an impaired vessel's response to vasoactive substances contribute to maintain elevated blood pressure levels in the chronic period. The aims of this study were to investigate in this animal model of hypertension: (1) if the increase in PKC activation was also found in the chronic stage; (2) the involvement of nitric oxide and insulin in the vessel's response; and plasma atrial natriuretic factor and nitrites/nitrates (nitric oxide metabolites) behavior. We evaluated the effects of: PKC-stimulator 12,13-phorbol dibutyrate, phenylephrine, insulin, nitric oxide synthase-inhibitor NG-nitro-L-arginine methyl esther (L-NAME) and PKC-inhibitor Calphostin C on aortic rings responses of Sprague-Dawley rats: fructose-fed and control. The fructose-fed group showed higher contractility to 12,13-phorbol dibutyrate than the control group in aortic rings pre-incubated with insulin, and this difference disappeared with L-NAME. The response to phenylephrine in rings pre-incubated with Calphostin C was decreased in the fructose-fed group and increased with Calphostin C plus L-NAME. Fructose-fed rats showed higher levels of plasma atrial natriuretic factor and nitrites/nitrates than controls. In conclusion, chronic fructose feeding seems to develop an impaired response to insulin, dependent on nitric oxide, suggesting a PKC alteration. Vasorelaxant agents, such as atrial natriuretic factor and nitric oxide, would behave as compensatory mechanisms in response to high blood pressure.

Detecting ligand binding to a small RNA target via saturation transfer difference NMR experiments in D(2)O and H(2)O

A small RNA motif is used as a target for ligand-based NMR-screening by saturation transfer difference (STD) NMR experiments. The prerequisites for using a small RNA target in STD experiments, such as saturation time, frequency, and pulses, are discussed. We also show that it is of advantage to use D2O as solvent instead of H2O due to the reduced R1 relaxation rate in D2O. The 27-nucleotide model of the ribosomal A-site was known to bind the aminoglycoside paromomycin with high affinity. This binding interaction could be detected easily, proving the effectiveness of STD NMR experiments as a screening tool for RNA-ligand interactions.

Clinical neurokinesiology of spastic gait

Locomotor control requires a spatiotemporal coordination of passive and active forces across the movement system. Both anticipatory and reactive strategies operate in locomotor control. Mammalian locomotion is based on a rhythmic, "pacemaker" activity of spinal stepping generators. Reflex modification of the gait cycle is task-, context- and especially phase-dependent. In spasticity, together with disturbed supraspinal control, the phase-dependent reflex modulation of the gait cycle is severely impaired and there is altered modulation and timing of muscle activation and relaxation during voluntary movement. There is also a poor correlation between EMG activity and tension development in the spastic muscle. The tension increases without sufficient muscle activation and disconnection and dyscoordination between muscle activation, tension development and motor performance develops. The pattern of muscle activation and the development of increased muscle tone in patients with spasticity may be dramatically different in active movement from that observed in clinical testing of the passive muscles. Strategies used in the functional treatment of spasticity should be aimed at training and activating residual motor function, suppression of pathological and unfavourable movement and postural patterns and preventing secondary complications. In the 1990s a number of new specific instrumental methods and technical equipment supporting gait rehabilitation in patients with CNS lesions were developed: rhythmic auditory stimulation and other types of rhythmic stimulation, partial body support, usually with treadmill walking, complex orthotic support of bipedal locomotion, multichannel functional electrical stimulation, usually with programmable computer control, and advanced gait trainers. In therapy of spastic gait, the functional goals should be clearly determined from the kinesiological point of view of the impairment, and the impact on disability and handicap should be considered and a multidisciplinary approach is essential. (Ref. 139.)

Regulation of cyclooxygenase activity and progesterone production in the rat corpus luteum by inducible nitric oxide synthase

This study explores interactions between the nitric oxide synthase (NOS) and the cyclooxygenase (COX) pathways in the regulation of progesterone production in early corpus luteum cells of rats. Nitric oxide (NO), prostaglandin E (PGE) and progesterone production was analysed in luteal cells of the rat corpus luteum exposed to inhibitors of non-specific NOS, inhibitors of inducible NOS (iNOS) and inhibitors of COX. Equine chorionic gonadotrophin (eCG)/hCG-primed rat corpus luteum cells produced NO, PGE and progesterone in a linear manner during 66 h of culture. Exposure of the cells to the non-specific NOS inhibitor, N(omega)-nitro-L-arginine (0.15 mmol l(-1)) for 48 h reduced NO, PGE and progesterone production to 21, 32 and 60% of that of the controls, respectively (P < 0.05 to P < 0.01). Another non-specific NOS inhibitor, N(omega)-methyl-L-arginine, produced similar inhibitions. Exposure of the cultured cells to S-ethylisothiourea (1 mmol l(-1)), a selective inhibitor of iNOS, suppressed the production of NO by 63%, PGE by 69% and progesterone by 48%. These findings indicate that production of PGE is regulated partly by iNOS, and that progesterone is probably regulated indirectly by the secondary changes in PGE. The addition of arachidonic acid to N(omega)-methyl-L-arginine-treated cells resulted in a significant increase in PGE and progesterone production (273 and 186%, respectively) without stimulating NO production. In contrast to the regulation exerted by the NO system on COX activity, the COX system does not modulate NO production in this model. This notion stems from the observation that the COX inhibitors acetylsalicylic acid (5 mmol l(-1)) and indomethacin (5 micromol l(-1)) suppressed PGE by 86 and 89%, respectively, and progesterone by 34 and 57%, respectively, but failed to inhibit NO production. The results from the present study indicate that iNOS-mediated NO production is involved in stimulating PGE synthesis in rat luteal cells, which may upregulate progesterone production.

Molecular and functional aspects of anionic channels activated during regulatory volume decrease in mammalian cells

The ability of cells to readjust their volume after swelling, a phenomenon known as regulatory volume decrease (RVD), is a fundamental biological achievement guaranteeing survival and function of cells under osmotic stress. This article reviews the mechanisms of RVD in mammalian cells with special emphasis on the activation of ion channels during RVD.

Treatment of cluster headache with topiramate: effects and side-effects in five patients

We report on clinical experience with topiramate in the prophylactic treatment of three patients with chronic and two patients with episodic, otherwise therapy-resistant, cluster headache. Patients were treated with daily doses of 75-200 mg topiramate. Topiramate was effective in three patients but proved ineffective and also caused intolerable side-effects in two patients. Topiramate may have prophylactic properties for treating cluster headache at lower doses than needed in epilepsy therapy, but its clinical value is limited due to central nervous system side-effects.

[Idiopathic eosinophilia with ascites (case report)]

Hypereosinophilia can present a diagnostic problem if initial diagnostic procedures (medical history, physical examination and basic laboratory exams) fail to reveal the cause. Persistent finding of hypereosinophilia in such patients demands diagnostic intervention in order to rule out neoplastic and lymphoproliferative diseases, chronic inflammatory diseases of respiratory and gastrointestinal system and skin, and other inflammatory and postinflammatory conditions. If these disorders are ruled out, consideration should also be given to the diagnosis of primary hypereosinophilia, including idiopathic hypereosinophilic syndrome. The paper presents a patient with significant elevation of absolute and relative numbers of eosinophils in whom the only physical pathologic finding was eosinophilic ascites. Extensive diagnostic investigation did not prove secondary character of abnormalities, and since all pathologic findings receded during 7-month observation without treatment, the conclusion was that the disorder was benign.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy: decrease in regional cerebral blood volume in hyperintense subcortical lesions inversely correlates with disability and cognitive performance

BACKGROUND AND PURPOSE

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an arteriopathic syndrome related to a genetic defect on chromosome 19. Characteristic changes in CADASIL can be observed onT2-weighted MR images in the subcortical white matter. The purpose of this study was to measure changes of regional cerebral blood volume (rCBV) with dynamic contrast-enhanced MR imaging and to correlate the changes to disability and cognitive performance.

METHODS

We obtained rCBV measurements of 24 individuals with proven CADASIL on a 1.5-T MR imaging unit. A susceptibility-weighted MR imaging sequence was used for bolus tracking. Principles of the indicator dilution theory were applied to estimate values of absolute rCBV (mL/100 g). Disability was determined by using the Rankin scale, and overall cognitive performance was assessed by using the Mini-Mental State Examination.

RESULTS

The mean rCBV in the subcortical white matter that was hyperintense on the T2-weighted images (2.7 +/- 0.8 mL/100 g) was significantly lower than the rCBV in the white matter that appeared normal on the T2-weighted images (4.4 +/- 1.3 mL/100 g) (P <.05). The mean rCBV in the gray matter was within the normal range (8.3 +/- 1.7 mL/100 g). Both cognitive impairment and disability negatively correlated with rCBV in the subcortical white matter that was hyperintense (P <.05) but not with rCBV in the normal appearing white matter. rCBV did not correlate with age.

CONCLUSION

rCBV measured in the hyperintense subcortical white matter in individuals with CADASIL was decreased and inversely correlated with disability and cognitive impairment.

Group epitope mapping by saturation transfer difference NMR to identify segments of a ligand in direct contact with a protein receptor

A protocol based on saturation transfer difference (STD) NMR spectra was developed to characterize the binding interactions at an atom level, termed group epitope mapping (GEM). As an example we chose the well-studied system of galactose binding to the 120-kDa lectin Ricinus communis agglutinin I (RCA(120)). As ligands we used methyl beta-D-galactoside and a biantennary decasaccharide. Analysis of the saturation transfer effects of methyl beta-D-galactoside showed that the H2, H3, and H4 protons are saturated to the highest degree, giving evidence of their close proximity to protons of the RCA(120) lectin. The direct interaction of the lectin with this region of the galactose is in excellent agreement with results obtained from the analysis of the binding specificities of many chemically modified galactose derivatives (Bhattacharyya, L.; Brewer, C. F. Eur. J. Biochem. 1988, 176, 207-212). This new NMR technique can identify the binding epitope of even complex ligands very quickly, which is a great improvement over time-consuming chemical modifications. Efficient GEM benefits from a relatively high off rate of the ligand and a large excess of the ligand over the receptor. Even for a ligand like the biantennary decasaccharide with micromolar binding affinity, the binding epitopes could easily be mapped to the terminal beta-D-Gal-(1-4)-beta-D-GlcNAc (beta-D-GlcNAc = N-acetyl-D-glucosamine) residues located at the nonreducing end of the two carbohydrate chains. The binding contribution of the terminal galactose residue is stronger than those of the penultimate GlcNAc residues. We could show that the GlcNAc residues bind "edge-on" with the region from H2 to H4, making contact with the protein. Analysis of STD NMR experiments performed under competitive conditions proved that the two saccharides studied bind at the same receptor site, thereby ruling out unspecific binding.

Structure and function of the ion channel ICln

Normal function of organs and cells is tightly linked to the cytoarchitecture. Control of the cell volume is therefore vital for the organism. A widely established strategy of cells to counteract swelling is the activation of chloride and potassium channels, which leads to a net efflux of salt followed by water - a process termed regulatory volume decrease. Since there is evidence for swelling-dependent chloride channels (IClswell) being activated also during pathological processes, the identification of the molecular entity underlying IClswell is of utmost importance. Several proteins are discussed as the channel forming IClswell, i.e. phospholemman, p-glycoprotein, CLC-3 and ICln. In this review we would like to focus on the properties of ICln, a protein cloned from a Madin Darby canine kidney (MDCK) cell library whose expression in Xenopus laevis oocytes resulted in a nucleotide sensitive outwardly rectifying chloride current closely resembling the biophysical properties of IClswell.

[Rehabilitation of patients with multiple sclerosis]

BACKGROUND

During the last decades a significant progress in rehabilitation of patients with multiple sclerosis (MS) has been achieved. This pilot study aims to study effect of weeks-lasting rehabilitation programme of MS patients in conditions of non-profiled inpatient rehabilitation unit.

METHODS AND RESULTS

The rehabilitation program of 25 hospitalised patients was mostly aimed at complex kinesitherapy and physical therapy, partly also at ergotherapy and orthetics. Functional status of patients was evaluated at the beginning of the hospital stay and before dismission. Spasticity of lower limbs was scored using Global Assessment of Spasticity Scale (GSA) and modified Ashwort's scale. Motor subscore of Functional Independence Measure (FIM) was used to assess the patient's disability. In interval of 5 to 6 months a questionnaire was distributed among the patients to evaluate the rehabilitation stay. During the rehabilitation none of the studied patients got worse. At the beginning of hospitalisation average EDSS was 6.7 (median 6.5) +/- 1.0, before the demission it was 6.5 (6.5) +/- 0.9. Among the parameters studied statistically significant improvement came in the modified Ashwort's scale (from 2.5 +/- 0.8 to 1.8 +/- 0.6) and in the motor subscore of Functional Independence Measure (from 59 +/- 15 to 64 +/- 14). No statistically significant difference was found when the Global Assessment of Spasticity Scale was used--the improvement score of the group was 1.0 +/- 0.7. Not all of questionnaires returned. The results obtained from responders showed positive evaluation of the rehabilitation program, which lasted for several months.

CONCLUSION

Results of the study correspond to the literary data both in immediate effects of the treatment and in its persistence after dismission. As important reveals the fact that most of the patients has primary or secondary progressive MS. It can be reasonably presumed that further improvement of the rehabilitation of patients with neurological diseases could be achieved in specialised neurorehabilitation centres.

[Sciatic paralysis after a buttock intramuscular injection in children: an ongoing risk factor]

Intramuscular injections are regularly recommended for the administration of certain drugs in children. This article underlines the fact that buttock intramuscular injection risks injury to the sciatic nerve, which may lead to lower limb palsy, most often presenting as paralytic drop foot. This condition rarely results from direct traumatic lesion of the sciatic nerve, but usually from the caustic effect of the injected drug. It may occur in older children and adolescents, as well as in infants and younger children. Therefore, the buttocks should not be used as an intramuscular injection site in children whatever their age. In the case of sciatic nerve injury following intramuscular injection, extrafascicular neurolysis may prevent the occurrence of paralysis.

The MetaFam Server: a comprehensive protein family resource

MetaFam is a comprehensive relational database of protein family information. This web-accessible resource integrates data from several primary sequence and secondary protein family databases. By pooling together the information from these disparate sources, MetaFam is able to provide the most complete protein family sets available. Users are able to explore the interrelationships among these primary and secondary databases using a powerful graphical visualization tool, MetaFamView. Additionally, users can identify corresponding sequence entries among the sequence databases, obtain a quick summary of corresponding families (and their sequence members) among the family databases, and even attempt to classify their own unassigned sequences. Hypertext links to the appropriate source databases are provided at every level of navigation. Global family database statistics and information are also provided. Public access to the data is available at http://metafam.ahc.umn.edu/.

[Hospitalization for systemic connective tissue diseases in Croatia in 1997: examples of the use of hospital morbidity registery data bases]

By using the explanatory analysis methods, we examined a possible model for the utilization of the Croatian Hospital Morbidity Register data for decision making in the managerial process for national health system development. To build a draft informational model, data were selected on 843 cases hospitalized in 1997 for diseases M30-M36 (ICD-10) in 45 health institutions. This was used as an index of the diagnostically/therapeutically most demanding group of rheumatic autoimmune diseases. Treatment standards were established for our health system for the patients having an M30-M36 disease by classifying Croatia's health institutions into four clusters by intensity of hospitalization, and by analyzing demographic characteristics and the length of stay by disease entity. These standards could represent a good informational base for forming consensus group panels to deal with inpatient treatment problems of patients with systemic connective tissue diseases.

Unit-independent reporting of laboratory test results

A variety of laboratory measurement units, assay systems, and reference values are presently being used in different clinical environments. There is therefore a challenge in provision of tools for presentation of laboratory data in harmonized forms that reduce the information load and reinforce clinical perception of test results. This paper describes the use of standard deviation (SD) units and logarithmic time graphical displays to improve presentation of laboratory test results. The SD concept employs strength of the change from normality as a diagnostic indicator, and the logarithmic time scale enables long-term overview of patient results. The suggested format is expected to promote effective transfer of test result information between laboratories, clinicians and hospitals.

Association of serum bilirubin concentration with risk of coronary artery disease

BACKGROUND

Lipid oxidation and formation of oxygen radicals are important elements of arterial plaque formation and atherosclerosis, and are involved in the pathophysiology of coronary artery disease (CAD). Because bilirubin has antioxidant properties, it has been suggested that it may have a protective role in the atherosclerotic process.

APPROACH

This review examines in vitro and in vivo studies indicating that bilirubin inhibits lipid oxidation and oxygen radical formation. Experimental and epidemiological evidence is presented that suggests that bilirubin may serve as a physiological antioxidant providing protection against atherosclerosis and CAD. Special attention is focused on studies that noted an inverse relationship between plasma bilirubin concentration and cardiovascular morbidity.

CONTENT

Serum bilirubin concentrations in the upper portion of the reference interval reportedly reduce atherogenic risk and provide protection against CAD. In contrast, serum bilirubin concentrations in the lower portion of the reference interval may be associated with increased risk of ischemic heart disease.

SUMMARY

Taken together, the evidence presented in this review supports the concept that bilirubin, via its antioxidant potential, has antiatherogenic properties and that an inverse relationship exists between circulating bilirubin concentrations and risk of CAD.

BiP and PDI cooperate in the oxidative folding of antibodies in vitro

Immunoglobulin heavy chain binding protein (BiP), a member of the Hsp70 chaperone family, and the oxidoreductase protein-disulfide isomerase (PDI) play an important role in the folding and oxidation of proteins in the endoplasmic reticulum. However, it was not clear whether both cooperate in this process. We show here that BiP and PDI act synergistically in the in vitro folding of the denatured and reduced Fab fragment. Several ATP-dependent cycles of binding, release, and rebinding of the unfolded antibody chains by BiP are required for efficient reactivation. Our data suggest that in the absence of BiP unfolded antibody chains collapse rapidly upon refolding, rendering cysteine side chains inaccessible for PDI. BiP binds the unfolded polypeptide chains and keeps them in a conformation in which the cysteine residues are accessible for PDI. These findings support the idea of a network of folding helper proteins in the endoplasmic reticulum, which makes this organelle a dedicated protein-processing compartment.

Genotype determination at the survival motor neuron locus in a normal population and SMA carriers using competitive PCR and primer extension

Precise quantitation of SMN1 copy number is of great interest in many clinical applications such as direct detection of SMA carriers or detection of an SMA-affected patient with a hemizygous deletion of the SMN1 gene. We describe a method that combines two independent nonradioactive PCR assays: determination of the relative ratio of the SMN1 and SMN2 genes using a primer extension assay and of the total SMN copy number using competitive PCR. Consistency of the results of two independent approaches ensures the reliability of the deduced genotype and thus avoids false interpretation of borderline results that can occur in quantitative assays. In all, 135 subjects were tested, including 91 normal controls and 44 SMA-affected children or SMA carriers. Two main genotypes were observed in controls: 2T/2C (45%) and 2T/1C (32%). A wide variability at the SMN locus is observed with nine different genotypes and up to six SMN genes. SMA carriers showed three frequent genotypes, 1T/2C (50%), 1T/3C (29%), and 1T/1C (18%). Normal chromosomes with two SMN1 genes per chromosome are not infrequent and thus, about 3% of SMA carriers are not detected using SMN1 copy number quantitation. Finally, as this method does not detect point mutations (4% of SMN1 gene mutations), reliability ranges from 93% to 100% depending on data available from the propositus.

Synthesis and cytotoxicity of gossypol related compounds

Gossypol, gossypolone, reduced gossypol and new Schiff's bases of racemic gossypol and gossypolone were extracted or synthesized. Their cytotoxic activities on KB human cancer cells were determined. Gossypolone and the ethylamine derivative of gossypolone were the most active compounds (IC(50) in the micromolar range in both cases). The cytotoxicity of gossypol and gossypolone was increased when the tests were performed in the absence of serum and decreased when catalase as well as mannitol were added to the culture medium.