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Biomedical subjects

Z Tóth

Publications and source records attributed to Z Tóth.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Biochemical and ultrasonic screening of chromosomal aneuploidies in the second trimester of pregnancy].

For prenatal screening of chromosomal aneuploidies (primarily the most frequent Down syndrome) maternal serum AFP screening in the second trimester of pregnancy has been supplemented by the determination of hCG in Hajdú-Bihar county. In pregnancies at risk on the basis of biochemical tests, a thorough, aimed ultrasound examination for the detection of minor and major anomalies characteristic for chromosomal abnormalities was carried out. If both biochemical and ultrasound examinations were suggestive of high risk prenatal karyotyping was offered. During a two-years prospective study 14328 pregnancies were screened. Authors could detect 38% of Down-syndrome cases prenatally, 5 cases in pregnant women at age under 35 years and at the same time the number of amniocenteses increased only by 70. It was concluded that 66% of all Down syndrome cases could have been prenatally diagnosed if prenatal chromosome test were performed in all cases at high risk on the basis of screening tests and maternal age.

Adult↗
PubMed1997

Intracranial pressure waves generated by high-energy short laser pulses can cause morphological damage in remote areas: comparison of the effects of 2.1-micron Ho:YAG and 1.06-micron Nd:YAG laser irradiations in the rat brain.

BACKGROUND AND OBJECTIVE: Histological effects of 2.1-micron Ho:YAG and 1.06-micron Nd:YAG laser pulses were compared in the rat brain, with special regard to areas remote from the irradiated site. STUDY DESIGN/MATERIALS AND METHODS: Laser pulses were delivered through a 0.6-mm glass fiber, the tip of which was either introduced into the caudate nucleus (application mode I), or held at a 2-mm distance above the exposed intact dura. In the latter case, the space between the dura and the fiber tip was filled either with physiological saline (application mode II) or with air (application mode III). RESULTS: In application modes I and II, but not in application mode III, Ho:YAG laser pulses of 1.5 J and 200 microseconds, but not Nd:YAG laser pulses with the same parameters, immediately caused morphological damage to a considerable number of neurons and axons randomly distributed among apparently normal ones in certain areas remote from the irradiated site. A decrease in the energy and an increase in the length of the pulses lowered the incidence of the remote morphological damage. CONCLUSION: This novel finding may impose limits on the application of Ho:YAG lasers in human endoscopic neurosurgery.

Animals↗
PubMed1997

The effect of fluoridated milk on human dental enamel in an in vitro demineralization model.

Fifty-seven sound human permanent premolars were demineralized for 14 days and then exposed to six different treatments: group 1, 1 mg/1 fluoride in milk for 7 days; group 2, 1 mg/l fluoride in milk for 14 days; group 3, 10 mg/l fluoride in milk for 7 days; group 4, 10 mg/l fluoride in milk for 14 days; group 5, control non-fluoridated milk for 14 days, and group 6, control tap water for 14 days. Enamel etch samples were taken and analysed for fluoride and for phosphorus. An increase in the enamel surface fluoride content was observed in groups 1-3. A statistically significant elevation (p < 0.01) of fluoride content and a significant decrease (p > 0.001) of acid solubility were found only in group 4.

Acid Etching, Dental↗
PubMed1997

A common morphological response of astrocytes to various injuries: "dark" astrocytes. A light and electron microscopic analysis.

Our previous studies showed that neurons became argyrophilic following different kinds of brain injuries. In the present study we demonstrated that astrocytes could also become argyrophilic following compressive or concussive head injuries and following intraperitoneal administration of pentylenetetrazole or kainic acid. Furthermore the soma, nucleus and processes of these argyrophilic astrocytes were shown in other preparations to be hyper-basophilic with the light microscope, and hyper-electron dense and shrunken at the ultrastructural level. When the head injuries were inflicted either at the 15th min. of perfusion-fixation or at the 30th min. of transcardial perfusion with chilled physiological saline, several astrocytes also became argyrophilic, hyper-basophilic, shrunken and hyper-electron dense. These data indicate that (i) the intracellular pathological event in these astrocytes is similar to that of "dark" neurons or "dark" cells of non-neural tissues, (ii) the formation of "dark" astrocytes can be independent of the actual state of metabolism, and (iii) the "dark" morphological state of astrocytes might have a role in neuropathological processes.

Animals↗
PubMed1996

[Usage modeling test in aerosols formulations].

Authors emphasize the importance of "usage-modelling" test concerning the uniformity of doses in the case of aerosol formulations, containing propellants or supplied with atomising devices. Weight measurement was carried out to identify the uniformity of doses per actuation keeping non-use periods in the case of water-based solutions with different density and suspension containing HFC propellants. It can be concluded that uniformity of doses--applying non-use periods during the testing time--significantly depends on the composition, the density of the formulation and the spraying mechanism of the atomising device.

Aerosols↗
PubMed1995

[Screening for congenital anomalies in mid-term pregnancy. Prospective epidemiologic study. Fetal trisomy].

The authors have presented their experiences on prenatal screening of fetal trisomies in this second part of a prospective study between 1988 and 1990. They gained their conclusions by processing 63,496 pregnancies during three years. The results show that maternal age plays the most important role in the prenatal screening of fetal trisomies in Hungary. They recommend fetal karyotyping for every pregnant woman aged 35 years or more. They emphasized that using of a combined screening method (i.e. maternal age, serum alpha-fetoprotein, human chorionic gonadotropin, oestriol) is only permissible if the hormonal and cytogenetic laboratory background are provided under standard circumstances. Since these are not available for the vast majority of pregnant women in Hungary they concluded that, at least for the time being, the main criteria for prenatal screening of fetal trisomies is the maternal age. By applying this recommendation 25-30 percentage of Down syndrome fetuses can be detected.

Adult↗
PubMed1995

Impact of prenatal mid-trimester screening on the prevalence of fetal structural anomalies: a prospective epidemiological study.

The objective of this study was to evaluate the effectiveness of the measurement of maternal serum alpha-fetoprotein (MSAFP) at 16 weeks and a subsequent routine ultrasound screening at 18-20 weeks' gestation and the impact on the birth prevalence of congenital structural anomalies in an unselected pregnant population of Hungary in a prospective epidemiological study. A total of 63,794 pregnant women (representing one-sixth of the population of Hungary) were offered this screening program over 3 years (1988-90). Of the pregnant population, 75.7% (48,312) received MSAFP screening and in 81.0% (51,675), at least one ultrasound scan was performed. In the screened pregnancies, 496 craniospinal, thoraco-abdominal, urogenital and other severe major anomalies occurred; 317 were detected at 18-20 weeks (sensitivity 63.1%; specificity 100.0%; positive predictive value 100.0%). The sensitivity of ultrasound scanning was significantly higher (p < 0.05) than that of the MSAFP screening. (At the time of ultrasound scanning the MSAFP value was known.) In this study, the less serious anomalies such as hydrocele, hypospadias and undescended testicle were not systematically searched for, but the birth prevalences were calculated. The overall mid-trimester prevalence of severe plus less severe major anomalies was 2.26%. The birth prevalences of severe major anomalies were 0.57 (craniospinal), 4.36 (thoracoabdominal and urogenital) and 1.21 (other severe) per 1000. These values were lower than the mid-trimester prevalences which were 2.94, 5.20 and 2.06 per 1000, respectively. The prevalence values at the age of 1 year were also calculated (0.36, 2.21, 0.54 per 1000, respectively). We conclude that our screening program with availability of termination of pregnancy could significantly (p < 0.05) reduce the prevalence of severe major abnormalities at birth. Training programs in cardiac scanning are required.

Abnormalities, Multiple↗
PubMed1993

[Screening of congenital anomalies in the mid-trimester of pregnancy. Prospective epidemiologic study. Developmental anomalies].

Authors report about the data of 60,000 pregnant women from three district counties of Eastern-Hungary between 1988 and 1990, on whom both ultrasound and alfa-fetoprotein screenings were performed. They demonstrate the value of this screening for the detection of fetal malformations and for the birth prevalence rate as well. This effective screening-protocol is proposed for a nation-wide application.

Abortion, Spontaneous↗
PubMed1992

[Physical measurement of the dorsal kyphosis in 14-17-year old patients with Scheuermann's disease and in matched healthy controls].

The modified use of the Debrunner-kyphometer (a special protractor to measure the dorsal kyphosis by an objective physical method) is presented. After proving the validity and reproducibility of the measuring method, the dorsal kyphosis of patients with Scheuermann's disease and of matched healthy controls was measured. The aim of the measurements was to assess the physiologic values of kyphosis and to investigate into the distribution of Scheuermann-patients regarding the grade of their dorsal sagittal curvature. In contrast with the everyday routine (subjective judgement of the sagittal curvatures or measuring on X-ray films), this method offers the advantage of an objective assessment without using X-rays. The presented simple method is recommended for screening school-children and for monitoring patients with Scheuermann's disease.

Adolescent↗
PubMed1992

Oxytocin nerve fibers innervate beta-endorphin neurons in the arcuate nucleus of the rat hypothalamus.

Fine, varicose oxytocin-containing nerve fibers have been demonstrated in the hypothalamic arcuate nucleus in rats. Using Phaseolus vulgaris leukoagglutinin as an anterograde tracer, fine neuronal fibers of paraventricular nucleus origin could be seen throughout the arcuate nucleus. Using double immunostaining, oxytocin-immunoreactive varicose fibers were observed around or in the close vicinity of beta-endorphin-immunoreactive neurons. Silver-gold-labeled oxytocin-immunoreactive presynaptic boutons were shown to make synaptic contacts with diaminobenzidine-labeled beta-endorphin-immunoreactive neurons by electron microscopy. These findings provide morphological evidence for a possible influence of oxytocin on the activity of the brain beta-endorphin system at the hypothalamic level.

Animals↗
PubMed1991

[Selective termination of the development of the defective fetus in discordant twin pregnancies].

Selective termination of the affected fetus in twin pregnancies was performed in the second trimester of seven pregnancies. The malformations included anencephaly/exencephaly (2 cases), hydrocephalus (1 case), thoracoabdominopagus of "B" and "C" cotwins (1 case), urethral obstruction sequence (1 case) and hygroma colli (2 cases). Intrauterine intervention on the affected fetus was done by transabdominal intracardial injection of 20% NaCl solution in the 15--24 weeks of gestation. All cases had dichorionic placentation. Unaffected co-twin infants were delivered at term with normal weight in 4 cases. In 2 cases the affected fetus was found in the lower gestational sac and both pregnancies, as well as the triplet pregnancy were lost 1--6 weeks and 3 weeks after the intervention, respectively. In the other cases, neither the mother, nor the survived fetus showed any complications. We believe that using hypertonic saline is lethal for the affected fetus but carries little or no risk either the other fetus or the mother, even if small amounts of the solution might inadvertently enter their circulation.

Abortion, Induced↗
PubMed1991

[Experience with chorionic villi sampling].

The authors discuss their experiences from 412 chorion villus samplings, (CVS), which they have done under four and a half years since 1985. They used eight types of instruments in performing their examinations and each instrument proved to be satisfactory in the gaining of chorion villus samples, suitable for further tests. They also discuss the bacteria found most frequently in the vagina on the basis of the examination and culturing of both vaginal and cervical fluid done prior to 151 CVS examinations and the effective method with which ascending infection can be prevented. They discuss a distributional pattern of their results based on the different indications for the CVS examinations, and the outcome of each of the pregnancies after CVS. In 377 cases they did direct karyotyping, in 30 cases DNA examination and in five cases enzyme determination also occurred.

Bacterial Infections↗
PubMed1991

[Oligohydramnios in mid-term pregnancy: analysis of 182 cases].

The outcome and pathological background of 182 pregnancies with mid-trimester oligohydramnios are discussed. Maternal serum alpha-fetoprotein (AFP) concentration in the 16th week of gestation was also determined in 119 cases. MSAFP in pregnancies with oligohydramnios associated urinary tract malformations was found to be mostly in the normal range, but it is often elevated in the cases without malformation. In addition, normal AFP was found in most cases, where the newborns survived the perinatal period. It can be concluded, that the elevated maternal serum AFP without ultrasonically detectable malformation refers to the extrafetal origin of the oligohydramnios, and it is recommended to take it into consideration in the genetic counselling practice.

Female↗
PubMed1991

Unusually late onset of cerebrospinal fluid rhinorrhea after head trauma.

Two cases of acute meningitis and cerebrospinal fluid rhinorrhea, in which the head trauma responsible occurred 10 and 30 years before, are presented. Intraoperatively, the brain parenchyma was found to be plugged into the fractured anterior fossa. By debridement and duraplasty from an intradural approach, both patients were cured. Several precipitating factors could be responsible for this unusually late reopening of the fistula. The possible accidental causes could be coughing or undetected microtraumas, but in the long run, atrophy of tissues and consequent changes in brain compliance with aging may play a role.

Acute Disease↗
PubMed1991

Diurnal Fluctuations in the Content and Functional Properties of the Light Harvesting Chlorophyll a/b Complex in Thylakoid Membranes : Correlation with the Diurnal Rhythm of the mRNA Level.

Diurnal fluctuations were observed in the content and some structural and functional properties of the light-harvesting chlorophyll (Chl) a/b pigment-protein complex of photosystem II (LHCII) in young developing wheat (Triticum aestivum) leaves grown under 16 hours light/8 hours dark illumination regime. The fluctuations could be correlated with the diurnal oscillation in the level of mRNA for LHCII. The most pronounced changes occurred in the basal segments of the leaves. They were weaker or hardly discernible in the middle and tip segments. As judged from the diurnal variations of the Chl-a/Chl-b molar ratio, the LHCII content of the thylakoid membranes peaked around 2 pm. This can be accounted for by the cumulative effect of the elevated level of mRNA in the morning and early afternoon. In the basal segment, the extent of the fluctuation in the LHCII content was approximately 25%, as determined from gel electrophoresis ("green gels"). The amplitude of the principal bands of the circular dichroism (CD) spectra of isolated chloroplasts paralleled the changes in the LHCII content. Our circular dichroism data suggest that the newly synthesized LHCII complexes are incorporated into the existing helically organized macrodomains of the pigment-protein complexes or themselves form such macrodomains in the thylakoid membranes. Chl-a fluorescence induction kinetics also showed diurnal variations especially in the basal segments of the leaves. This most likely indicates fluctuations in the ability of membranes to undergo "state transitions." These observations suggest a physiological role of diurnal rhythm of mRNA for LHCII in young developing leaves.

Journal Article↗