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Biomedical subjects

I Kiss

Publications and source records attributed to I Kiss.

At least 199 records · Page 11Linked to original sources
PubMed1981

[Perioperative opiate analgesia (author's transl)].

22 patients undergoing gynaecological surgery were given general anaesthesia supplemented by epidural morphine during and after the operation. The fentanyl requirements during the operation were significantly lower than they were in a control group and postoperative administration of analgesics could be dispensed with. The method is particularly suitable for patients at risk because less anaesthetic agents are needed. Postoperative epidural opiate analgesia is also useful after epidural anaesthesia; doses of 3.0 mg of morphine produced no side-effects except pruritus.

Anesthesia, Epidural↗
PubMed1980

RNA-polymerase binding at the promoters of the rRNA genes of Escherichia coli.

The promoter region of two bacterial rRNA genes was investigated by electron-microscopic analysis of polymerase binding, transcription initiation and nitrocellulose filtration of RNA-polymerase-DNA complexes, using restriction endonuclease generated fragments of recombinant plasmids and a transducing phage. The following observations have been made: 1. Two transcription initiation sites have been located approximately 200 and 300 base pairs upstream from the beginning of the sequence coding for mature 16 S rRNA. 2. Polymerase binding at these sites can be observed electronmicroscopically and a 360 base-pair fragment containing these sites binds to nitrocellulose in the presence of RNA-polymerase. This complex dissociates even at moderately high (0.1-0.2 M) salt concentrations. Although transcription initiation is reported to be more frequent at the first of these sites, the binding is much stronger at the second site. 3. In the case of the rrnD gene, BamHI cleaves a few base pairs upstream from the first transcription start site. This cleavage destroys polymerase binding at this site but does not influence binding at the second site. 4. At higher polymerase/DNA ratio four weak but distinct and regularly spaced binding sites can be observed preceding the two initiation sites at approximately 1000, 820, 640 and 440 base pairs before the mature 16 S rRNA sequence. 5. An extremely strong binding site is located about 1300 base pairs upstream from the beginning of the 16 S rRNA sequence. Very little (if any) initiation occurs at this site. The possibility is discussed that the noninitiating binding sites preceding the two transcription start points might functionally belong to the promoter region.

Binding Sites↗
PubMed1979

Functional characteristics of an identified pair of neurones in the CNS of the pond snail (Lymnaea stagnalis L.).

The properties of 2 giant electrically coupled neurones (A10 and P1) identified in the visceral and right parietal ganglia of Lymnaea stagnalis were examined. The active and passive electrical parameters of the neurones, as well as the junction between them were measured. The main peripheral and interneuronal connections of the neurones were demonstrated using both electrophysiological and morphological methods. It is shown that the coupled cells are not neurones of the same function, but they are asymmetrical ones. This finding is supported by the following results: (1) the axonal pathways of neurones A10 and P1 are different; (2) there are significant differences in their afferent and efferent connections; (3) though the electrical junction between them is bidirectional, the junctional electrical characteristics prefer P1-A10 transmission. According to the electron microscopic results both neurones are possible neurosecretory cells. The differences demonstrated between the 2 giant neurones may have significance concerning their role in a special neuronal network.

Action Potentials↗
PubMed1979

Electronic transmission between giant neurones identified in the CNS or Lymnaea stagnalis.

In the CNS of Lymnaea stagnalis it was verified for two paired cells (A11--A11' and P1--A10) that the interneuronal connection is realized by electronic transmission. The evidences of electrical coupling: 1:1 synchronity of spontaneous activities; the delay of transmission is less than that in the case of a chemical synapse; any neurone can drive the firing of its own coupled pair; the transmission is bidirectional both for depolarization and hyperpolarization. The active and passive electrical constants of the electrical junctions were estimated. The coupling coefficients appeared to be relatively large. The coupling coefficient and the junctional resistance depend on the stimulating current to a high degree. The value of capacity of junction exceeds that of soma, or is equal to it, and is a function of the stimulating current, so the characteristics of the transmission are determined by a variable impedance, rather than by a simple ohmic resistance. The morphological properties of the junctions were examined with light microscope using intracellular CoCl2 staining. It is suggested that cell A11' may be derived from an anomalous duplication of cell A11. The morphological and functional differences between the two paired cells examined are reflected in the detailed properties of the junctions. These differences between the two paired cells examined are reflected in the detailed properties of the junctions. These differences may have a significance concerning the role of the paired cells in the neuronal network.

Animals↗
PubMed1979

The passive electrical characteristics of giant neurones identified in the central nervous system of Lymnaea stagnalis.

The passive electrical characteristics of four giant neurones in the CNS of Lymnaea stagnalis were studied. The parameters were calculated on the basis of potential transients evoked by hyperpolarizing square impulses. The examined neurones can be classified in two groups, which show significant differences considering the time constant and membrane resistance. This classification is in correlation with the functional properties of the cells. The differences in the passive electrical characteristics of the giant neurones were compared to some data obtained by using voltage clamp method. The role of these parameters in the generation of the single spike and the rhythmic discharge is discussed.

Action Potentials↗
PubMed1978

In vitro transscription of ribosomal RNA on phage lambdarifd 18 DNA.

In vitro transcription of ribosomal RNA was studied on the DNA of the transducing bacteriphage lambdarifd 18, which carries an rRNA transcription unit from Escherichia coli. rRNA synthesis was preferential at all polymerase/DNA ratios tested, and at the optimal 0.3 weight ratio nearly 60% of the transcript was rRNA. At this ratio the principal product of transcription comigrated in acrylamide-agarose electrophoresis with authentic 30-S rRNA precursor synthesized in vivo. In the presence of rifampicin more than one equivalent of rRNA was synthesized, thus suggesting the existence of two initiation sites for rRNA on the phage DNA. Similar results were obtained on E. coli DNA. Preincubation with heparin virtually eliminated the transcription of rRNA, in sharp contrast with the results of similar experiments on bacterial DNA where rRNA genes were transcribed 4--5 times in the presence of heparin. The possible explanation of this difference between rRNA promotors on the phage and the bacterial DNA are discussed.

Coliphages↗
PubMed1978

Cloning of an E. coli ribosomal RNA gene and its promoter region from lambdarifd18.

The DNA of the specialized transducing phage lambdarifd18, which carries a bacterial rRNA transcription unit, was digested with restriction enzymes EcoRI and/or BamHI. Attempts were made to clone fragments containing the presumed rRNA promoter region or the entire rRNA gene in RSF2124 or pBR313 plasmid vectors with the following results: (1) We failed to clone an EcoRI fragment with the rRNA promoter region in plasmid RSF2124. (2) A smaller EcoRI-BamHI fragment with the rRNA promoter was also unclonable by itself, but one recombinant was found containing this fragment together with another large (7 Mdaltons) fragment, derived from phage lambda. The presence of this large fragment proved to be essential. The identity of these DNA fragments in the recombinant clone was confirmed by redigestion with several restriction enzymes, hybridization with rRNA, and in vitro transcription experiments, which showed preferential rRNA transcription. (3) A BamHI fragment encompassing the entire rRNA gene was easily cloned. Such stable clones carried a doubled number of rRNA genes. In vitro transcription using the recombinant plasmid resulted in 70% rRNA transcription. These recombinant clones allow the easy purification of the relevant DNA fragments for further investigation including sequencing.

Chromosome Mapping↗
PubMed1978

Relation between radiation resistance and salt sensitivity of spores of five strains of Clostridium botulinum types A, B, and E.

The NaCl tolerance of different strains of Clostridium botulinum varies over a wide range, and the patterns of NaCl inhibition differ distinctly and characteristically from strain to strain. The more radiation-resistant strains, such as 33A, 62A, and 7272A, are more resistant to NaCl, whereas the more radiation-sensitive strains, such as 51B and 1304E, are more sensitive to NaCl. This rule appears to hold irrespective of whether the spores were unirradiated controls or whether they were radiation damaged prior to exposure to NaCl in the recovery media. The data seem to indicate that radiation doses in the shoulder portion of the radiation survival curves did not noticeably sensitive the spores to NaCl, whereas radiation doses in the exponential-decline portion of the survival curve invariably produced a distinct sensitization. Thus, strains 33A and 62A were not sensitized to NaCl by 0.3 to 0.4 Mrad, i.e., in the shoulder portion of the survival curve. Radiation-sensitive strain 51B, which shows no distinct shoulder in its survival curve, was sensitized to NaCl by 0.1 Mrad, the lowest radiation dose employed in this study. These observations seem to suggest a possible relationship between deoxyribonucleic acid repair capacity and salt tolerance.

Cesium Radioisotopes↗
PubMed1977

Cytological investigation of biopsy performed in sarcoidosis.

One of the most frequent appearance of sarcoidosis is the enlargement of mediastinal lymph-nodes. The clinical picture first of all must be distinguished from the malignant processes and seldom from lymph-node tuberculosis. At our clinic material was obtained for cytological examination in two ways: through mediastinoscopy in the course of which we had opportunity of histological evaluation too and by means of transbronchial thin-needle puncture respectively and only cytological examination was performed with this material. We carried out investigations in 155 patients sent to our clinic on account of the suspicion of sarcoidosis. According to the course of disease or rather other examinations 123 out of 155 patients suffered from sarcoidosis and in 112 of these cases that is in 91% the diagnosis was verified by the help of cytological examination. In the smears epithelioid cell groups were generally found in large number but Langhans' giant cells could be produced only in 21 cases. In 70 of 123 patients mediastinoscopy and in 53 transbronchial thin-needle biopsy was accomplished. Through cytological investigation of material obtained mediastinoscopically we attained nearly 100% positivity rate and 80% by the help of thin-needle biopsy. Although forasmuch as the transbronchial puncture does not need special intervention because it can be carried out in the course of routine bronchoscopy we think the application of the procedure reasonable not only in finding metastasis if it involves the hypertrophy of mediastinal lymph-nodes. In this way we spare the patient from further examinations. The cytological finding, of course, must be always fitted in clinical picture but on the basis of our experience the close cooperation between the clinician and cytologist assures the avoidance of wrong diagnosis.

Biopsy, Needle↗
PubMed1977

Electron microscopic investigation of a giant neuron identified in the right parietal ganglion of Lymnaea stagnalis (L).

The ultrastructure of a giant neuron (GRP1) identified in the right parietal ganglion of Lymnaea stagnalis was examined. The results suggest that GRP1 is a neurosecretory cell. The perikaryon is characterized by many neurosecretory-like granules of variable electron density. The average diameter (longer axis) of the granules was 1850 A. Furthermore highly-developed rough endoplasmic reticulum and Golgi complex were observed in the cytoplasm. Synapse-like structures were often found on the somatic membrane, but typical, true synaptic endings were not seen.

Animals↗