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Biomedical subjects

L Kiss

Publications and source records attributed to L Kiss.

At least 19 recordsLinked to original sources
PubMed1991

Stochastic resonance in a single neuron model: theory and analog simulation.

Here, we consider a noisy, bistable, single neuron model in the presence of periodic external modulation. The modulation induces a correlated switching between states driven by the noise. The information flow through the system, from the modulation, or signal, to the output switching events, leads to a succession of strong peaks in the power spectrum. The signal-to-noise ratio (SNR) obtained from this power spectrum is a measure of the information content in the neuron response. With increasing noise intensity, the SNR passes through a maximum: an effect which has been called stochastic resonance, and which was first advanced as a possible explanation of the observed periodicity in the recurrences of the Earth's ice ages. We treat the problem within the framework of a recently developed approximate theory, valid in the limits of weak noise intensity, weak periodic forcing and low forcing frequency, for both additive and multiplicative noise. Moreover, we have constructed an analog simulator of the neuron which demonstrates the stochastic resonance effect, and with which we have measured the SNRs for comparison with the theoretical results. Our model should be of interest in situations where a single inherently noisy neuron is the receptor of a periodic signal, which is itself noisy, either from the network or from an external source.

Animals↗
PubMed1991

[Urinary N-acetyl-beta-D-glucosaminidase activity in healthy, polycythemic and hypoxic newborn infants].

Urinary N-acetyl-beta-D-glucosaminidase (NAG) activity was assayed in 20 polycythemic newborns and prematures, together with 50 prematures suffering from hypoxia on the 1st, 2nd, 4th, 14th, and 28th day after birth. The enzyme was also assayed in 101 healthy newborns which provided normal reference values. NAG activity was factored by the creatinine concentration to given an index. There were significant difference in the NAG indices either between full-term and preterm babies or between appropriate for gestational age (AGA) and small for gestational age (SGA) neonates of the normal group. However, NAG excretion on the first day of life was significantly raised in the case of polycythemic newborns. Following partial plasma exchange, on the 14th day the NAG activity returned to the normal range. NAG activities of premature babies suffering from idiopathic respiratory distress syndrome (IRDS) were significantly elevated on the 1st, 2nd, 4th day but fell sharply to the 14th day. NAG activity fell to normal values by the 28th day. These results suggest that the urinary NAG index is a sensitive indicator of the renal tubular damage during the newborn period.

Acetylglucosaminidase↗
PubMed1991

The efficacy of intravesical BCG in the treatment of patients with high risk superficial bladder cancer.

Sixty-two patients with superficial bladder cancer stage T1 with or without dysplasia or carcinoma in situ and 34 patients with stage TA associated with dysplasia or carcinoma in situ were treated by TUR and TUR + BCG, respectively, and were followed up for an average of 46 months (6-192) and 32 months (6-72), respectively, after therapy. The recurrence rate (61%), progression (37%) and tumour death (19%) were unfavourably high in the group of patients treated by TUR only. On the contrary, the effect of intravesical BCG therapy was excellent. Recurrence rate was as low as 20.5%, and progression and tumour death were not detected in any patient. Intravesical BCG seems to be the best choice for treatment of high risk superficial bladder cancer. The authors recommend their effective modified treatment schedules.

Adult↗
PubMed1991

Clonal distribution of K1 and K5 antigen possessing Escherichia coli isolates.

A significant difference was observed in the occurrence of the examined markers (Col+, ColV+, Hly+, Aer+, AbR) and in the plasmid carrier state between strains with and without K1 and K5 antigens. Plasmids of the same size were harboured by serotypes possessing K1 and K5 antigens, e.g. among O1: K1: H- strains plasmids of 60-79 Md, among O1: K1: H7, O18ac: K1: H7, O45: K1: H7 and O83: K1: H- strains plasmids of 80-95 Md were frequent. The average plasmid number was higher in K1 strains than in K5 strains. In serogroup O1 the frequency of the plasmid carrier state was associated with the O serogroup and not with the K antigen. The plasmid number in K5 of serogroups O6 and O18 was lower than in K5- strains. Plasmids of 80-95 Md were predominant among the strains derived from blood and cerebrospinal fluid, whereas these plasmids were rare among the K1 and K5 strains isolated from other sources. Plasmids of 60-79 Md were frequent among strains derived from different sources. The 30-40 Md plasmids were relatively frequent among strains isolated from urine. In contrast with literary data, O1: K1: H-, O1: K1: H7 and other frequent serotypes consisted of different clones. Different clones were found within a single serotype, too.

Anti-Bacterial Agents↗
PubMed1991

Acute acalculous cholecystitis.

In 1884 Duncan was the first to report on acute postoperative acalculous cholecystitis (ref.: 14). Initial publications reported a small number of cases. Literary data have shown a change of the situation for the past few decades /16/. It was most frequently observed following surgical intervention, trauma, delivery or parenteral nutrition /1, 13, 16/. The number of new acalculous cholecystitis cases often requiring surgical intervention and causing death in elderly male patients has increased /5, 16/. Therefore we decided to undertake a clinical study. In Hungary the authors who deal with this theme are: Csengódy /2/, Sándor /17/, Lukács /12/ and Ezer et al. /3/.

Acute Disease↗
PubMed1991

Urinary N-acetyl-beta-D-glucosaminidase activity in healthy, polycythemic and hypoxic neonates.

The authors investigated the urinary N-acetyl-beta-D-glucosaminidase (NAG) activity in the case of 101 normal healthy and 20 polycythemic newborns and prematures, and 50 prematures suffering from hypoxia on the 1st, 2nd, 4th, 14th, and 28th day after birth. The obtained activities were referred to the creatinine concentrations of the urine samples and given as NAG index. There were no significant differences in the NAG indices either between fullterm and preterm babies or between appropriate for gestational age (AGA) and small for gestational age (SGA) neonates of the normal group. The NAG indices on the first day of life were significantly higher in the case of polycythemic newborn in comparison with the normal group (p less than 0.01). On the 14th day, after the partial plasma exchange, the NAG indices returned to the normal range. The premature babies suffering from IRDS received an average 10.1 days oxygen supplementation. Their NAG indices were significantly (p less than 0.01) higher on the 1st, 2nd, 4th days than those of the healthy prematures of the normal group and decreased considerably up to the 14th day. Finally the NAG indices reached the normal value on the 28th day. These results support the assumption that the urinary NAG index is a suitable indicator of the renal tubular damage during the newborn period.

Acetylglucosaminidase↗
PubMed1990

The effect of polycythemia and hypoxia on urinary N-acetyl-beta-D-glucosaminidase activity in newborns.

Urinary N-acetyl-beta-D-glucosaminidase activity was assayed in fullterm and preterm polycythemic neonates, in preterm infants with hypoxia, and in healthy newborns. There were no significant differences between fullterm and preterm babies or between appropriate for gestational age and small for gestational age neonates in the normal group. N-acetyl-beta-D-glucosaminidase excretion on the first day of life was significantly raised in polycythemic newborns (P less than 0.01). Fourteen days after partial plasma exchange the enzyme activity returned to normal. N-acetyl-beta-D-glucosaminidase activities in preterm babies with respiratory distress syndrome were significantly (P less than 0.01) raised on the 1st, 2nd, 4th days and fell sharply to the 14th day. N-acetyl-beta-D-glucosaminidase isoenzyme studies revealed that urine samples taken from preterm babies with respiratory distress syndrome in the first week after birth contained increased amounts of intermediate and B isoenzyme forms while there was a concomitant reduction in the amount of the A form present.

Acetylglucosaminidase↗
PubMed1990

[Results of BCG immunotherapy in the management of bladder tumors].

The authors reported their results of BCG immunotherapy in the treatment of the bladder cancer. between 1984-1989 60 superficial and 4 muscle infiltrative bladder tumors were treated. The results of 53 BCG treated superficial bladder cancer group were compared to control groups. The recurrence cases three-four times, the progressive cases eight-ten times were more in the control groups than it was found in the BCG group. They could not establish the value of BCG in the treatment of muscle infiltrative bladder cancer, because they had not appropriate number of patients and they could find only few articles in the literature. The authors surveied the last literature of BCG immuntherapy and verified that BCG had an important role in the treatment of the bladder cancer and searching the action of antitumor effect of BCG would add more useful information to cancer immunology.

BCG Vaccine↗