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Biomedical subjects

I Kiss

Publications and source records attributed to I Kiss.

At least 145 records · Page 8Linked to original sources
PubMed1989

Effects of precocene analogs on the nematode Caenorhabditis remanei (var. Bangaloreiensis). I. Structure/activity relations.

Precocenes (PI and PII) and 114 of their analogs (PAs) were synthetized and tested on C. remanei embryos for their precocene-like (P-like) activities resulting in unusual development at sublethal doses. The P-like activity was quantitated by plotting the probit of the percentage of the developmentally affected survivors against the (log) dose to obtain the EC plot and the half effective concentration (EC50). All five PAs (PI, PII, 7-ethoxy-PII, 7-(prop-2-ynyloxy)-PI, and 6-methoxy-7-(prop-2-ynyloxy)-PII) which exert both antiallatal activity in insects and P-like activity in nematodes are 7-alkoxy-substituted 2,2-dimethylchromenes. Both activities can be enhanced by an additional 6-MeO-substitution or by an asymmetric 6,7-dialkoxy-substitution, on condition that R-7 is longer than R-6. There are many more similarities than dissimilarities in the structural requirements needed for antiallatal and P-like activities. All but three nonantiallatal PAs effective in nematodes are 7-prop-2-ynyloxy-subsituted; two are symmetrically 6,7-disubstituted, and one is heterosubstituted (thio-PI). All PAs with antiallatal but without P-like activity are 7-monosubstituted with a relatively long alkoxy group. Certain substitutions favor antiallatal activity and others P-like activity. The severe nematocidal effect of 6,7-methylenedioxy-2,2-dimethylchromene (inert in insects) is not accompanied by P-like activity. The present findings lend some indirect support to the supposition that JH-producing cells and/or JH-dependent function(s) might exist in the nematodes.

Animals↗
PubMed1989

Improved artifact rejection and isolation of compound action potentials by means of digital subtraction.

When recording compound action potentials (CAPs) elicited by stimulating near the recording site, it may prove difficult to distinguish the CAP from the shock artifact because of their overlap in time. This problem is compounded when a pair of stimulation pulses is delivered because the CAP elicited by the test pulse (T pulse) may be partially superimposed on the artifact and response elicited by the conditioning pulse (C pulse) as well as on the T pulse artifact. Methods based on digital subtraction were used to address these problems. A record was obtained with the C-T interval adjusted to be slightly less than the absolute refractory period so that the T pulse would fail to elicit a CAP. A record consisting of a C pulse artifact and response was subtracted from this record to yield a 'pure' shock artifact. In principle, subtracting this 'artifact-only' record from records obtained with single pulses removes the shock artifact and yields a 'pure' response. An extension of this method was used to isolate T pulse responses from the C pulse artifact, C pulse response, and T pulse artifact. These methods proved effective in improving the isolation of the CAPs of interest from other features of the raw records. Limitations of the techniques and their complementarity with other methods of artifact reduction are discussed.

Action Potentials↗
PubMed1989

Retrospective analysis of clinical data of normotensive and hypertensive pregnant women and their newborns.

The medical history of 256 hypertensive and 263 normotensive pregnant women was analysed retrospectively. There was a negative correlation (P less than 0.01) between the maximal pretreatment diastolic blood pressure and the birth weight of newborns in the hypertensive group. The prevalence of a hypertensive family history, pyelonephritis, proteinuria, delivery by Caesarean section, fetal asphyxia during delivery and death of the newborn during delivery was significantly higher in the hypertensive group than in the normotensive one. The gestational age at delivery was shorter and the birth weight of the newborn was lower in the hypertensive women than in the normotensive women.

Antihypertensive Agents↗
PubMed1989

Influence of anesthetics--nitrous oxide in particular--on electromyographic response evoked by transcranial electrical stimulation of the cortex.

The influence of anesthetics usually used for neuroleptic anesthesia--nitrous oxide, fetanyl, flunitrazepam, and thiopental sodium--on motor evoked potentials (MEP) was examined in 15 patients during neurosurgical operations on the spinal cord, in 16 patients in traumatic coma, and in 6 healthy volunteers. MEP were recorded from the contralateral thenar and anterior tibial muscles in response to single transcranial electrical stimuli on the motor cortex. Intraoperatively, during neuroleptic anesthesia we found the amplitudes to be reduced to an average of 11% of the preoperative baselines for the thenar potentials, and to 7% of the preoperative baselines for the anterior tibial muscle potentials, despite a maximum stimulus strength of 750 V. A similar reduction of MEP amplitudes was observed in 6 volunteers during breathing of an oxygen/nitrous oxide mixture (34%/66%), whereas fentanyl, flunitrazepam, and thiopental had only a minor effect on MEP. We conclude that with respect to anesthesia-related suppression of amplitudes, an average of 5 to 15 electromyographic responses should be evaluated for intraoperative monitoring of MEP using the technique described here.

Adult↗
PubMed1989

A parieto-occipital generator for P300: evidence from human intracranial recordings.

Auditory event-related potentials (ERPs) were recorded simultaneously from the scalp and from bilateral intracranial sites within the frontal and temporal lobes, as well as from intracortical sites in the parieto-occipital region in a subject undergoing evaluation for surgical treatment of medically intractable epilepsy. Scalp ERP morphology was entirely normal. Large amplitude ERPs could be recorded from all intracranial sites. Furthermore, polarity inversions of ERP components with latencies similar to that of the scalp P300 were recorded in both temporal lobes and from the parieto-occipital region. These findings are consistent with suggestions that multiple intracranial generators, including extratemporal ones, give rise to the scalp-recorded P300. These data also provide a basis for a conceptual link between hypotheses concerning the neural substrate of attention and the psychological correlates of the P300.

Adult↗
PubMed1989

Protein kinase C in larval brain of wild-type and dunce memory-mutant Drosophila.

Protein kinase C activity has been measured in extracts of larval brain of Drosophila melanogaster, with the synthetic nonapeptide substrate Ala-Ala-Ala-Ser-Phe-Lys-Ala-Lys-Lys-amide. Protein kinase C activity in such extracts is abolished in a Ca2+-dependent manner at 18 degrees C, and partly converted to a form independent of effectors. The decay of protein kinase C activity can be prevented by leupeptin or a crude calpastatin preparation isolated from fly heads, indicating the presence of the Ca2+-dependent neutral protease, calpain, in larval brains. The total protein kinase C levels were nearly the same in wild type and three different dunce "memory-mutant" strains. In contrast, the soluble/particulate activity ratios were different: wild-type, 0.91; dunce M11, 0.46; dunce M11/Df(1)dm75e19, 1.23; dunce2, 0.88. These data suggest that the membrane adherence of protein kinase C in larval brain is governed by the actor of genes other than dunce.

Animals↗
PubMed1989

The antiallatal effects on locusts and lethal effects on nematodes of synthetic precocene-1 derivatives differing at the carbon 7 position.

Fourteen precocene-1 (P1) derivatives differing at C-7 were synthetized and tested for their antiallatal activities on Locusta migratoria (in vitro and in vivo) and nematocidal effects on Caenorhaditis elegans. An outstanding antiallatal effect was produced by 7-propargyloxy-P1 in vitro. It caused an elevated rate of mortality when applied in vivo to locusts or nematodes. The antiallatal effect of 7-cyclopentyloxy-P1 was not accompanied by toxicity. Aralkyloxy substitution at C-7 eliminated the precocene activity.

Animals↗
PubMed1989

Determination and kinetics of antibody response to Candida albicans in ulcerative colitis.

Levels of antibody against the mannan component of Candida albicans cell wall were determined and followed in 57 ulcerative colitis patients. The appearance of higher titers suggests an intermittent (benign) clinical course of the disease. Lower titer values at repeated checks are associated with a continuous (severe) clinical course. Our data suggest that Candida albicans antibody titer values may be used as an indicator of the clinical outcome of ulcerative colitis.

Adult↗
PubMed1989

[A bone cement containing methotrexate in an experiment and in clinical practice].

The authors submit their initial experience with the use of bone cement with methotrexate in the treatment of primary and secondary malignities of bones. As a basis they use the analogy of using bone cement with gentamycin the molecular structure of which is similar to that of methtrexate. In the experimental part of the work in vitro evidence was provided of methotrexate stability when exposed to heat or oxidation; and the kinetics of its release from pores of bone cement were revealed. In experimental dogs the effect of cement with methotrexate on neighbouring bone was investigated in the early period in the immediate vicinity necrosis of the trabeculae was found, during the late period healing processes. The clinical use of bone cement with methotrexate was started in 1986. In 17 surviving patients only in one case local progression of a tumour in the vicinity of cement with methotrexate was found. The aim of the work is to find a possible local treatment of bone malignities, in particular metastatic ones, which will be not only an emergency solution but will extend our therapeutic possibilities.

Animals↗
PubMed1988

Drosophila homolog of the murine Int-1 protooncogene.

We have isolated phage clones from Drosophila melanogaster genomic and cDNA libraries containing a sequence homologous to the murine Int-1 protooncogene. The Drosophila gene is represented by a single locus at position 28A1-2 on chromosome 2. The gene is expressed as a 2.9-kilobase-long polyadenylylated mRNA in embryo, larval, and pupal stages. It is hardly detectable in adult flies. The longest open reading frame of the cDNA clone corresponds to a protein 469 amino acids long. Alignment of the predicted amino acid sequences shows that the Drosophila protein is 86 amino acids longer than its murine counterpart. In spite of the difference in length, the two proteins are highly conserved with an overall sequence homology of 54%. Both Drosophila and murine Int-1 proteins begin with a hydrophobic leader sequence and contain cysteine residues and sites for glycosylation (four in the murine protein and one in the Drosophila protein) in conserved positions, suggesting that they play important functional roles.

Amino Acid Sequence↗
PubMed1988

Interactions and developmental effects of mutations in the Broad-Complex of Drosophila melanogaster.

The 2B5 region on the X chromosome of Drosophila melanogaster forms an early ecdysone puff at the end of the third larval instar. The region contains a complex genetic locus, the Broad-Complex (BR-C) composed of four groups of fully complementing (br, rbp, l(1)2Bc, and l(1)2Bd) alleles, and classes of noncomplementing (npr 1) and partially noncomplementing l(1)2Bab alleles. BR-C mutants prevent metamorphosis, including the morphogenesis of imaginal discs. Results are presented that indicate that the BR-C contains two major functional domains. One, the br domain is primarily, if not exclusively, involved in the elongation and eversion of appendages by imaginal discs. The second, the l(1)2Bc domain, is primarily involved in the fusion of discs to form a continuous adult epidermis. Nonetheless, the two domains may encode products with related functions because in some situations mutants in both domains appear to affect similar developmental processes.

Alleles↗
PubMed1988

Interaction of the Stubble-stubbloid locus and the Broad-complex of Drosophila melanogaster.

The 2B5 region on the X chromosome of Drosophila melanogaster forms an early ecdysone puff at the end of the third instar. The region is coextensive with a complex genetic locus, the Broad-Complex (BR-C). The BR-C is a regulatory gene that contains two major functional domains, the br domain and the l(1)2Bc domain. BR-C mutants prevent metamorphosis, including morphogenesis of imaginal discs; br mutants prevent elongation and eversion of appendages and l(1)2Bc mutants prevent fusion of the discs. The Stubble-stubbloid (Sb-sbd) locus at 89B9-10 is best known for the effects of its mutants on bristle structure. Mutants of the BR-C and the Sb-sbd locus interact to produce severe malformation of appendages. Viable heteroallelic and homoallelic combinations of Sb-sbd mutants, including loss-of-function mutants, affect the elongation of imaginal disc appendages. Thus, the Sb-sbd+ product is essential for normal appendage elongation. Sb-sbd mutants, however, do not affect eversion or fusion of discs. Correspondingly, only BR-C mutants deficient in br function interact with Sb-sbd mutants. The interaction occurs in deficiency heterozygotes using single, wild-type doses of the BR-C, of the Sb-sbd locus, or of both loci. These last results are formally consistent with the possibility that the BR-C acts as a positive regulator of the Sb-sbd locus. The data do not exclude other possible nonregulatory interactions between the two loci, e.g., interactions between the products of both genes.

Alleles↗
PubMed1988

Clinical studies with captopril treatment of hypertensive patients.

Haemodynamic and humoral effects of captopril were studied in patients with essential and renovascular hypertension. Captopril decreased significantly both systolic and diastolic blood pressure and moderately, it reduced also the heart rate. On the basis of the haemodynamic effects our patients could be divided into two groups: in patients where the total peripheral resistance (TPR) exceeded 2000 dyn x sec x cm-5 during rest, captopril exerted its hypotensive effect by decreasing TPR. In patients in whom TPR was lower, the hypotensive action could be attributed to the reduction of cardiac output (CO). Captopril increased plasma renin activity, and decreased the activity of angiotensin converting enzyme (ACE) in the plasma. In acute study captopril did not influence plasma noradrenaline level but increased it during long-term administration. It did not affect dopamine or adrenaline levels. Captopril had no effect on plasma beta-endorphin concentration, moreover, the opiate antagonist, naloxone, failed to antagonize its antihypertensive effect. Comparing the acute effects of Capoten (Squibb, USA) and Tensiomin (EGIS, HUNGARY) no significant differences were found.

Biomechanical Phenomena↗