Evaluating the efficiency of the Dental Teacher system as a digital preclinical teaching tool

AIM

To investigate the use of a preparation evaluation system for enhancing the learning and performance of undergraduate dental students when cutting preparations.

MATERIALS AND METHODS

Two groups of eighteen students each were randomly chosen from the fourth year of the dental programme. The task chosen for this study was to make a cavity in preparation for a mesio-occlusal ceramic onlay in a plastic tooth. The dimensions of the cavity were defined, and 2 burs of known size were used for preparation. For assessment, each tooth preparation was scanned with a digital scanner and analysed using the Dental Teacher software. In the control group, a second corrective preparation was made following the supervisor's instructions. In the test group, the second preparation was made based on Dental Teacher analysis. The final cavities were all scanned and assessed by Dental Teacher comparing the similarity of students' onlay cavity preparations to the ideal preparation. All data were recorded and analysed by the software, including cavity depth and width in the occlusal and proximal box, the extent of mesiobuccal cusp reduction and shoulder width around the mesiobuccal cusp. Finally, the data were statistically evaluated using a Wilcoxon matched pairs test and a Mann-Whitney U test.

RESULTS

Three of the 6 cavity dimension parameters improved significantly in the test group whilst no improvement was found in the control group. A positive correlation was found between the improvement and the deviation measured for the first preparations, and it was stronger in the test group than in the control group.

CONCLUSIONS

The use of Dental Teacher helped students to learn the preparation technique for onlay restorations more efficiently and seems to be a promising and useful method to facilitate their individual performance. Student feedback showed a great demand for digital aids in education.

Could vectors' fear of predators reduce the spread of plant diseases?

Predators influence the behaviour of prey and by doing so they potentially reduce pathogen transmission by a vector. Arthropod predators have been shown to reduce the consumption of plant biomass by pest herbivores, but their cascading non-consumptive effect on vector insects' feeding behaviour and subsequent pathogen transmission has not been investigated experimentally before. Here we experimentally examined predator-mediated pathogen transmission mechanisms using the plant pathogen Wheat Dwarf Virus that is transmitted by the leafhopper, Psammotettix alienus. We applied in situ hybridization to localize which leaf tissues were infected with transmitted virus DNA in barley host plants, proving that virus occurrence is restricted to phloem tissues. In the presence of the spider predator, Tibellus oblongus, we recorded the within leaf feeding behaviour of the herbivore using electrical penetration graph. The leafhopper altered its feeding behaviour in response to predation risk. Phloem ingestion, the feeding phase when virus acquisition occurs, was delayed and was less frequent. The phase when pathogen inoculation takes place, via the secretion of virus infected vector saliva, was shorter when predator was present. Our study thus provides experimental evidence that predators can potentially limit the spread of plant pathogens solely through influencing the feeding behaviour of vector organisms.

Assessment of heat provocation tests on the human gingiva: the effect of periodontal disease and smoking

Periodontal inflammation is associated with morphological changes in the blood vessels which may influence the regulation of gingival blood flow (GBF). Our aim was to adapt the heat provocation test to the human gingiva to assess vascular reactivity in periodontal inflammation.

METHOD

GBF was recorded by Laser Doppler Flowmetry before and after heat provocation in healthy volunteers (n = 50). Heat was generated either by warm saline or a halogen lamp. The latter method was also utilized for a heat test in non-smoking and smoking patients with periodontal inflammation. The circulatory parameters were correlated to the inflammatory marker, i.e. gingival crevicular fluid (GCF) production measured by Periotron.

RESULTS

Local application of heat caused a rapid, significant and transient increase in GBF regardless of the method used. The increase in the speed and not in the concentration of moving blood cells was responsible for increased GBF. Higher GCF values were correlated with increased peak flow, flux pulse amplitude and faster restoration of GBF after the test in non-smokers, but not in smokers.

CONCLUSIONS

The heat test could be a valuable tool to check the vascular reactivity of gingival vessels. Moderate periodontal inflammation may facilitate gingival vascular responsiveness which can be suppressed by smoking.

Molecular Diagnostic Challenges and Complex Management of Consecutive Twin Pregnancies in a Family with CD40 Ligand Deficiency

X-linked hyper-IgM syndrome (XHIGM) is a primary immunodeficiency disorder (PID) caused by mutation in the gene encoding the CD40 ligand (CD40L) expressed on activated T cells. Prenatal genotyping in carriers with twin pregnancies is more challenging than in women with singleton pregnancies. In addition, women with twin pregnancies may decide on selective termination for which the risk of loss of the healthy foetus may exceed 7%. We report here on a family affected by XHIGM. Diagnosis of the disease was made in a male patient as late as 33 years of age. After family screening, the sister of the proband conceived male twins in two consecutive pregnancies. In the first pregnancy, one of the male foetuses was hemizygous for the c.521A>G (Q174R) mutation in the CD40L gene. In the second pregnancy, ultrasound scan showed one foetus to have exencephaly and karyotyping revealed this foetus to have trisomy 18. Several options were discussed, but the parents decided on selective termination in both pregnancies. The interventions were successful in both cases, and the mother now has two healthy sons. This report demonstrates the way in which advanced technologies in molecular medicine and obstetric interventions may assist families with decisions about possible selective termination in case of life-threatening molecular or chromosomal disorders. Diagnosis of CD40L deficiency at the age of 33 years in the proband was striking and indicated that PIDs are still neglected as disease entities in the evaluation of patients with recurrent severe infectious diseases.

Genetic relatedness in wintering groups of house sparrows (Passer domesticus)

Social behaviour of group-living animals is often influenced by the relatedness of individuals, thus understanding the genetic structure of groups is important for the interpretation of costs and benefits of social interactions. In this study, we investigated genetic relatedness in feeding aggregations of free-living house sparrows (Passer domesticus) during the nonbreeding season. This species is a frequent model system for studies of social behaviour (e.g. aggression, social foraging), but we lack adequate information on the kin structure of sparrow flocks. During two winters, we ringed and observed sparrows at feeding stations, and used resightings to identify stable flock-members and to calculate association indices between birds. We genotyped the birds using seven highly polymorphic microsatellite loci, and estimated pairwise relatedness coefficients and relatedness categories (close kin vs. unrelated) by maximum likelihood method. We found that most birds were unrelated to each other in the flocks (mean +/- SE relatedness coefficient: 0.06 +/- 0.002), although most individuals had at least a few close relatives in their home flock (14.3 +/- 0.6% of flock-mates). Pairwise association between individuals was not significantly related to their genetic relatedness. Furthermore, there was no difference between within-flock vs. between-flock relatedness, and birds had similar proportions of close kin within and outside their home flock. Finally, relatedness among members of different flocks was unrelated to the distance between their flocks. Thus, sparrow flocks were not characterized by association of relatives, nevertheless the presence of some close kin may provide opportunity for kin-biased behaviours to evolve.

Aerosol optical depth, aerosol composition and air pollution during summer and winter conditions in Budapest

The dependence of aerosol optical depth (AOD) on air particulate concentrations in the mixing layer height (MLH) was studied in Budapest in July 2003 and January 2004. During the campaigns gaseous (CO, SO(2), NO(x), O(3)), solid components (PM(2.5), PM(10)), as well as ionic species (ammonium, sulfate and nitrate) were measured at several urban and suburban sites. Additional data were collected from the Budapest air quality monitoring network. AOD was measured by a ground-based sun photometer. The mixing layer height and other common meteorological parameters were recorded. A linear relationship was found between the AOD and the columnar aerosol burden; the best linear fit (R(2)=0.96) was obtained for the secondary sulfate aerosol due to its mostly homogeneous spatial distribution and its optically active size range. The linear relationship is less pronounced for the PM(2.5) and PM(10) fractions since local emissions are very heterogeneous in time and space. The results indicate the importance of the mixing layer height in determining pollutant concentrations. During the winter campaign, when the boundary layer decreases to levels in between the altitudes of the sampling stations, measured concentrations showed significant differences due to different local sources and long-range transport. In the MLH time series unexpected nocturnal peaks were observed. The nocturnal increase of the MLH coincided with decreasing concentrations of all pollutants except for ozone; the ozone concentration increase indicates nocturnal vertical mixing between different air layers.

Effect of increased UV-B radiation on the anthocyanin content of maize ( Zea mays L.) leaves

The level of UV-B radiation reaching the surface of the earth is increasing due to the thinning of the ozone layer in the stratosphere over recent decades. This has numerous negative effects on living organisms.Some of the Hungarian inbred maize lines examined under the climatic conditions in Chile exhibited an unusually high proportion of pollen mortality, flowering asynchrony and barrenness. The evidence suggests that this can be attributed to the approx. 30% greater UV-B radiation in Chile.The investigation of this problem within the framework of abiotic stress breeding programmes is extremely important in the light of the global rise in UV-B radiation, which may make it necessary to elaborate a selection programme to develop inbred lines with better tolerance of this type of radiation.In the course of the experiment the same ten inbred lines, having different maturity dates and genetic backgrounds, were tested for five years in Chile and Hungary. The tests focussed on anthocyanin, a flavonoid derivative involved in the absorption of damaging UV-B radiation.Averaged over years and varieties, the total anthocyanin content in the leaf samples was significantly higher in Chile than in Hungary. This was presumably a response at the metabolic level to the negative stress represented by higher UV-B radiation.In the five early-maturing flint lines the anthocyanin contents were more than 45% greater than those recorded in Hungary. This suggests that these genotypes, originating from northern regions, were not sufficiently adapted to the higher radiation level. In these samples higher UV-B caused a sharp rise in the quantity of anthocyanin, which absorbs the dangerous radiation. In late-maturing genotypes the initial content of the protective compound anthocyanin was higher at both locations, so in these types the high radiation level was not a problem and did not cause any substantial change.Similar conclusions were drawn from the results of fluorescence imaging. The F440/F690 ratio indicative of the stress level was higher in late lines with a high anthocyanin content, good tolerance and good adaptability.

Novel amplitude and frequency demodulation algorithm for a virtual dynamic atomic force microscope

Frequency-modulated atomic force microscopy (FM-AFM; also called non-contact atomic force microscopy) is the prevailing operation mode in (sub-)atomic resolution vacuum applications. A major obstacle that prohibits a wider application range is the low frame capture rate. The speed of FM-AFM is limited by the low bandwidth of the automatic gain control (AGC) and frequency demodulation loops. In this work we describe a novel algorithm that can be used to overcome these weaknesses. We analysed the settling times of the proposed loops and that of the complete system, and we found that an approximately 70-fold improvement can be achieved over the existing real and virtual atomic force microscopes. We show that proportional-integral-differential controllers perform better in the frequency demodulation loop than conventional proportional-integral controllers. We demonstrate that the signal to noise ratio of the proposed system is 5.7 × 10(-5), which agrees with that of the conventional systems; thus, the new algorithm would improve the performance of FM-AFMs without compromising the resolution.

Novel calretinin and reelin expressing neuronal population includes Cajal-Retzius-type cells in the neocortex of adult pigs

Cajal-Retzius cells and their secreted product reelin are essential for the lamination of the cerebral cortex. In all species studied to date Cajal-Retzius cells form a transient neuronal population that almost completely disappears from the neocortex postnatally. Recently, in the hippocampal formation of adult domestic pig, we have found a large calretinin- and reelin-immunoreactive cell population that morphologically corresponded to Cajal-Retzius cells. In the present study, we examined calretinin- and reelin-immunoreactive neurons in layer I of the prefrontal, temporal, parietal and occipital neocortical areas of newborn, young adult and adult domestic pigs. Large numbers of bipolar or fusiform calretinin-positive cells were found in the upper half of layer I in all examined age groups. The morphology of these neurons resembled that of the Cajal-Retzius cells. Layer I was occupied by a dense calretinin-positive axonal plexus that was similar to the previously described axons of Cajal-Retzius cells in other species. In a similar location, where calretinin-positive cells occurred in layer I, large numbers of reelin-immunoreactive cells were found in all examined age groups. In addition, reelin colocalized with calretinin in layer I neurons. The number of calretinin and reelin-positive neurons decreased from 1 day to one year, but calretinin-positive Cajal-Retzius-type cells still comprised a remarkable large population in 12-month-old animals. Correlated light and electron microscopic examination of calretinin-labeled Cajal-Retzius-type cells indicated that these cells are integrated in the synaptic circuitry of the neocortex. Our results suggest that Cajal-Retzius cells do not disappear inevitably from the mature neocortex in all mammalian species. The function of this cell type is not known, but late persisting Cajal-Retzius-type cells in the domestic pig provide an opportunity to study their neuronal connections and the possible role of reelin in plasticity and regeneration of neocortex.

Aortic cannulation and cardiopulmonary bypass independently produce selective brain lesions in pig

Whether cardiopulmonary bypass alone or together with the manipulation of the aorta produce neurological complication remains controversial. Using a domestic pig model of cardiopulmonary bypass, we investigated the immediate effects of aortic cannulation and cardiopulmonary bypass on neuronal injury in different brain regions. We compared the presence of neuronal injury in three experimental groups: non-operated controls (n = 3); operated controls with aortic cannulation without cardiopulmonary bypass (n = 5); operated animals undergoing cardiopulmonary bypass (n = 5). Pyknotic cells were counted in the prefrontal cortex, cerebellum and in the hippocampal formation. Calretinin immunohistochemistry was used to show possible ischemic damages in the hippocampus which is known to be one of the most sensitive brain regions to ischemia. Decreased calretinin immunoreaction and reduced number of calretinin-positive neurons were observed in the hippocampal dentate gyrus following aortic cannulation or cardiopulmonary bypass compared to the non-operated control group. Changes were more severe following cardiopulmonary bypass than after cannulation of the aorta alone. The frequency of pyknotic cell nuclei was not different in the control and experimental groups. Our experimental study suggests that both cannulation of the aorta alone and cardiopulmonary bypass affect a selected population of neurons.

Role of hypothalamic inputs in maintaining pituitary-adrenal responsiveness in repeated restraint

The role of hypothalamic structures in the regulation of chronic stress responses was studied by lesioning the mediobasal hypothalamus or the paraventricular nucleus of hypothalamus (PVH). Rats were acutely (60 min) and/or repeatedly (for 7 days) restrained. In controls, a single restraint elevated the plasma adrenocorticotropin (ACTH), corticosterone, and prolactin levels. Repeated restraint produced all signs of chronic stress, including decreased body and thymus weights, increased adrenal weight, basal corticosterone levels, and proopiomelanocortin (POMC) mRNA expression in the anterior pituitary. Some adaptation to repeated restraint of the ACTH response, but not of other hormonal responses, was seen. Lesioning of the mediobasal hypothalamus abolished the hormonal response and POMC mRNA activation to acute and/or repeated restraint, suggesting that the hypothalamo-pituitary-adrenal axis activation during repeated restraint is centrally driven. PVH lesion inhibited the ACTH and corticosterone rise to the first restraint by approximately 50%. In repeatedly restrained rats with PVH lesion, the ACTH response to the last restraint was reduced almost to basal control levels, and the elevation of POMC mRNA level was prevented. PVH seems to be important for the repeated restraint-induced ACTH and POMC mRNA stimulation, but it appears to partially mediate other restraint-induced hormonal changes.

Surface modifications induced by ns and sub-ps excimer laser pulses on titanium implant material

Medical implants used in oral and orthopaedic surgery are mainly produced from titanium. Their biological behaviour, e.g. osseointegration, essentially depends on both the chemical composition and the morphology of the surface. Modifications achieved by excimer laser irradiation of titanium samples were investigated in order to improve their surface characteristics so as to facilitate biointegration. To enlarge the effective interfacial area of bone-implant contact, holes were ablated by laser pulses of ns or sub-ps length. During ns ablation, crown-like projecting rims formed around the borders of the holes. Ultra-short (0.5ps) KrF excimer laser pulses were successfully applied to avoid these undesirable formations. Since a smooth dental implant surface is necessary to maintain a healthy connection with the soft tissues, laser polishing of samples was investigated, too. Irradiation with a series of ns laser pulses resulted in effective smoothing, as measured with atomic force microscope. X-ray photoelectron spectroscopy analysis of the laser-polished titanium surface revealed that laser treatment led to a decrease of the surface contamination and in thickening of the oxide layer. X-ray diffraction measurements demonstrated that the original alpha-titanium crystal structure was preserved.

Effects of structural modifications of N-CPM-normorphine derivatives on agonist and antagonist activities in isolated organs

The agonistic and antagonistic properties of N-cyclopropylmethyl (N-CPM) morphine derivatives were observed in mouse vas deferens (MVD), longitudinal muscle of guinea pig ileum (GPI) and rabbit vas deferens (LVD). In MVD the K(e) values of the titled compounds (N-CPM-morphine, N-CPM-isomorphine, N-CPM-dihydromorphine, N-CPM-dihydroisomorpPhine, N-CPM-dihydromorphone and naltrexone) were measured for mu-, kappa- and delta-receptors using normorphine, ethylketocyclazocine (EKC) and D-Pen2-D-Pen5-enkephaline (DPDPE) as selective agonists on the receptors, respectively. For mu-receptors of MVD the tested compounds showed similar affinity. For kappa-receptors the non-iso-6-OH derivatives possessed much less affinity than the iso-derivatives. Similar difference could be observed for delta-receptors. The agonistic activities of these compounds in MVD were observed to be between 0-20% of the inhibition of muscle contractions. In GPI the compounds except naltrexone possessed strong agonistic activities effectively antagonized by nor-binaltorphimine (nor-BNI) (K(e) of nor-BNI was 0.23 nM) suggesting that they were strong kappa-receptor agonists. We investigated these agents in LVD too, which contains kappa-receptors, but they did not produce any agonist potencies. It raises the possibility that the kappa-receptor subtypes of LVD and MVD are different from the kappa-receptor subtype of GPI or the vasa deferentia contain much fewer kappa-receptors than GPI and the intrinsic activities of these compounds are too small to reach the 50% inhibition of the contractions.

Idiopathic myelofibrosis with prominent postsplenectomy erythroblastosis terminating in acute myeloid transformation

Idiopathic myelofibrosis is a myeloproliferative disease with poor prognosis and without sufficient therapy. Acute leukemic transformation occurs in 15% of patients. The authors report the case of a 63 year old myelofibrotic patient treated with splenectomy. During the clinical course they observed unusually prominent and persistent erythroblastosis in the peripherial blood. After a two years long, relatively stable period the disease terminated in acute myeloid leukemia.

Breath holding test in preeclampsia: lack of evidence for altered cerebral vascular reactivity

Twenty-five healthy and thirty-one preeclamptic pregnant women were assessed by means of transcranial Doppler sonography. Resting cerebral blood flow velocities in the middle cerebral arteries were measured followed by a repeat measurement 30 s after breath holding. Absolute blood flow velocities and per cent changes after breath holding procedure were compared between the groups. Absolute blood flow velocities were higher in preeclamptic pregnant women both at rest and after breath holding. The percent increase in cerebral blood flow velocity after breath holding (cerebral vascular reactivity) was similar in the two groups. Our data suggest that cerebral vascular reactivity is preserved in pregnant women with preeclampsia.

[Dental implantation at the maxilla with autologous bone transplantation]

In the Department of Maxillofacial and Oral Surgery of County Hospital of Szentes, different types of bone losses of the maxillary alveolar ridge have been treated since 1 March, 1990. The applied surgical procedures were the following: 1. 394 patients were treated with GBR technique and 567 DenTi implants were inserted for these patients. 2. In 47 cases autogenous bone grafts were harvested from mandibular cortica and 78 DenTi implants were placed. Altogether 14 implants were lost; the success rate was 97.81% in the period between 1 March, 1990 and 31 January, 2001. 3. The severely resorbed maxillary alveolar ridge was replaced by rigid autogenous bone graft harvested from the ilium or from tibia. The bone graft was fixed with implants to the recipient surface. This method was applied in 36 cases from 1 February, 1992 until 31 January, 2001. 147 DenTi implants were inserted and 7 of them were lost. The success rate was 97.28%. Our results have indicated that the dental implants had accelerated the remodelling process of the transplanted autogenous bone and the success rate of the simultaneously performed dental implants were comparable to that of the two stage procedures in which dental implants were inserted several weeks following bone grafting. Based on our long-term favourable clinical experience this technique has been proven to be an excellent method for correcting and replacing the lost maxillary alveolar ridges as well as the circumscribed alveolar bony defects.

[The role of uterine and umbilical artery Doppler velocimetry for the early detection of pathologic pregnancy]

Pregnancy induced hypertension remains the most frequent reason of maternal and fetal complications. Recent studies of the entire pathophysiology of the abnormal implantation proved association between the impaired placental performance and the reduced uteroplacental circulation. Therefore the Doppler examination of uterine and umbilical blood flow may provide the early recognition of high-risk pregnancies complicated by maternal hypertension and fetal intrauterine growth retardation. The authors endeavor to describe the details and characteristics of uteroplacental haemodynamic changes during the course of physiologic and defective implantation. On the basis of the currently available scientific publications they summarize the role of the uterine and umbilical artery Doppler velocimetry as a screening tool in the detection of the consequences of the impaired uteroplacental perfusion. They conclude that abnormal velocity waveforms obtained from the uterine and umbilical arteries may help to improve the efficacy of the prenatal care and the perinatal outcome as well. The clinical benefits of this screening method will be precisely defined on the basis of further multicenter studies in Hungary.

[Reproducibility of the laser fluorescence method for the diagnosis of occlusal caries. Clinical study]

The aim of the study was to assess the reproducibility of recently developed laser fluorescence method for occlusal caries detection in vivo. 71 non-cavitated premolar and molar teeth were examined repeatedly by three dentists using DIAGNOdent (KaVo) instrument. The presence of caries has been established on the classification of Lussi, created on the basis of "in vitro" investigations. The reproducibility of the measurements were expressed in rank correlation of Spearman. The intra- and interexaminer reliability was also determined by Kappa statistics. The Spearman correlation coefficiencies were fairly high (0.738-0.949) The intraobserver and interobserver coincidencies reflected by Kappa values (0.60-0.88 and 0.44-0.77, respectively) were also convincing.

Susceptibility of dopamine D5 receptor targeted mice to cysteamine

BACKGROUND

Recently we demonstrated that gastric mucosa of rats can synthesize, store and release dopamine. Out of five different subtypes, mRNA of D5 (=D1b) dopamine receptor is very abundant in the gastric epithelium. D1 receptor selective dopamine agonists have been shown to protect against experimental gastro-duodenal lesions.

AIMS

To test the hypothesis that protective effects of dopamine involve D5 receptors, mucosal lesions were induced in D5 receptor deficient (KO) and wild-type (WT) mice using cysteamine. Morphology and gastric acid secretion of D5 KO mice were also studied.

METHODS

Single doses of 600 mg/kg, 300 mg/kg cysteamine or vehicle were administered subcutaneously to fasted animals. After 24 h, number and severity of gastro-duodenal lesions were analyzed. Basal and histamine-induced maximal gastric acid output were measured by a stomach-sac wash-through method.

RESULTS

All the KOs in the 600 mg/kg cysteamine group died within 4 h showing symptoms of toxicity while three out of four WTs survived (P<0.05). Mortality after 300 mg/kg cysteamine was significantly higher in KOs versus the WTs: 6/14 versus 2/11, P<0.05. Gastric lesion-index was also significantly higher in KOs (median, middle quartile): four (3-9) versus 0 (0-0), P<0.05. Duodenal lesions did not develop from this single dose of cysteamine in either genotype. Basal and histamine-induced maximal gastric acid output were comparable in the two genotypes.

CONCLUSIONS

This study demonstrates that loss of D5 receptor causes mucosal vulnerability and increased toxicity of cysteamine in genetically manipulated mice. Thus, D5 receptor subtype is indeed likely to be involved in protective effects of dopamine in the stomach.

3D reconstruction based on hard tissue microtome cross-section pictures in dentistry

The aim of this study was to examine the accuracy of the computerized 3D surface analyzing and volume measuring method in dentistry. Two different types of test objects were used in the first part of the measurements. Each sample of the two groups was cross-sectioned using a hard tissue microtome. The sections were photographed on both sides and were projected on a graphical tablet and analyzed using a computer program. The measured and calculated parameters were compared. In the second part, 200 microm thick horizontal sections were prepared from 11 human incisor roots using the hard tissue microtome. This way, five sections were prepared from the apical 2 mm of each root. The effects of section thickness and number were modeled by decreasing the inclusion rate of the obtained number of sections from 10 to 2 and its influence on the calculated results was determined. This method was suitable for the approximation and analysis of 3D parameters. The results indicated that using 200-300 microm section thickness, the measured values were approximately 8-21% lower than the real parameters.

[Some depth-psychological aspects of the psychogenic symptoms of oro-facial tissues]

The specificity of the oral psychogenic manifestations is based on the unique psychological and depth-psychological function of the mouth, and teeth during infancy (breasting), sexuality, and aggressivity. Fixed dentures, implants, and especially removable dentures can modify strongly these psychological functions and activate oral fixations leading to psychogenic symptoms. In the present paper the great importance of the oral phase of the development of personality and the symbolical values of the mouth, teeth, tongue, and face in the oro-facial conversive symptom manifestations are discussed.

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.

Alterations in corticotropin-releasing hormone gene expression of central amygdaloid neurons following long-term paraventricular lesions and adrenalectomy

Corticotropin-releasing hormone messenger RNA expression in the amygdala of rats after adrenalectomy and bilateral lesions of the hypothalamic paraventricular nucleus was examined by in situ hybridization histochemistry. Corticotropin-releasing hormone messenger RNA-containing cells are abundant in the intermediate subdivision of the central amygdaloid nucleus. Some corticotropin-releasing hormone-labeled cells are scattered in other subdivisions of the central nucleus and throughout the anterior amygdaloid area. Five days after bilateral adrenalectomy, the number of corticotropin-releasing hormone messenger RNA-containing cells was reduced both in the central nucleus and the anterior area of the amygdala. This reduction was prevented by corticosterone replacement and contrasts sharply with the known rise of corticotropin-releasing hormone messenger RNA in the paraventricular nucleus after adrenalectomy. Corticotropin-releasing hormone messenger RNA expression in the amygdala was up-regulated in rats with six-week bilateral lesions of the paraventricular nucleus. This elevation in corticotropin-releasing hormone messenger RNA was not influenced by adrenalectomy or corticosterone, and it did not correlate with plasma levels of adrenocorticotrophic hormone or corticosterone. The possible direct innervation of the amygdala by the paraventricular nucleus is supported by the demonstration of labeled axons from the paraventricular nucleus to the amygdala after injection of an anterograde tracer, Phaseolus vulgaris leucoagglutinin, into the paraventricular nucleus. Labeled fibers take two courses: through the lateral hypothalamus ventral amygdalofugal path and through the stria terminalis. Data presented here suggest that the paraventricular nucleus-amygdala connection is likely to be inhibitory to corticotropin-releasing hormone neurons in the central amygdala. These neurons may participate in behavioral responses to stress effected through brainstem autonomic centers rather than directly through the hypothalamo-pituitary adrenal axis.

Quality assurance in obstetric and gynecologic ultrasound. The Hungarian model

The majority of physicians performing obstetric scans are radiologists and obstetricians. The radiologist is well trained in imaging but lacks the obstetric background required to interpret information obtained from the scan. The obstetrician is qualified in obstetric knowledge but often lacks the formal imaging training necessary to optimize the pictures. In Hungary, nearly 100% of the physicians who perform obstetric and gynecologic scans are obstetricians. In order to create a standard and to hold together the practitioners in obstetrics and gynecology, as well as to eliminate the serious consequences of clinical malpractice, we organized the Hungarian Society of Ultrasound in Obstetrics and Gynecology in 1992. The Society was established according to the standards of the most skilled obstetricians and gynecologists. In addition to working out the conditions and the standards, the Society provides for its members continuous education, postgraduate training, and monitors the knowledge and level of practitioners. We have established three levels of qualification. Each level requires a medical undergraduate degree. The levels range from basic (A), intermediate (B), to specialist (C). To receive the certificate every user and ultrasound laboratory have to fulfill requirements based on skill as well as equipment and circumstances. The certificates are valid for one year. Every year the practitioner must pass a special examination at the appropriate level. By doing so, the Society provides its members with not only professional support, but ethical and legal security as well.

Biclonal primary plasma cell leukemia

Authors present a multiparameter pathological study in a case of rapid biclonal primary plasma cell leukemia. The immunohistochemical data revealed aberrant phenotypes (monocyte, epithelial and T-cell) probably in connection with microenvironmental influences. Biclonality can be attributed to class switching during malignant transformation. Static image cytometry showed aneuploidy. The blasts of this process are active immunoregulatory cells.

Ventriculomegaly with radial and renal defects: prenatal diagnosis in two consecutive sibs

We describe two consecutive mid-trimester fetuses of different sexes with identical anomalies of the upper limbs and the kidneys in association with severe ventriculomegaly. We compare this apparently autosomal recessive syndrome to VACTERL-H association, Fanconi anemia, and two other, so far unparalleled syndromes. Taking into account the absence of chromosome breaks, the associated changes of the amniotic fluid, and the renal histology, we conclude that we are dealing with a different entity.

[Use of erythropoietin in pregnancy: review of the literature in connection with 2 cases]

Recently a growing number of case reports has been published about successful pregnancy outcome of dialysed women on recombinant human erythropoietin therapy. During pregnancy the maternal demand for erythropoietin may undergo changes, with consideration of recombinant human erythropoietin therapy in the early stage of renal insufficiency, as is shown by our two reported cases. The use of recombinant human erythropoietin seems to be safe for the foetus: it does not cross the placental barrier, and therefore lacks any direct foetal effect. The treatment of anaemia with recombinant human erythropoietin carries benefits for both the mother and foetus. One of the most important preconditions for successful recombinant human erythropoietin therapy is adequate iron supplementation. Due to the increased risk of pregnancy induced hypertension or preeclampsia, there is a need for slow and gradual correction of anaemia, and an individually tailored target hematocrit. A close follow up of he patient by the obstetrical-nephrological team is essential, with the intensive monitoring of the fetuses. In some cases with normal renal function the stimulation of erythropoiesis with recombinant human erythropoietin may also be needed during the pregnancy.

Conformationally constrained deltorphin analogs with 2-aminotetralin-2-carboxylic acid in position 3

Two approaches to the design of very active and highly selective delta opioid peptides were used to obtain new deltorpin analogs with altered hydrophobic and stereoelectronic properties. Deltorphin I and II analogs were synthesized involving the substitution of Ile instead of Val at positions 5 and 6 in the address domain and 2-aminotetralin-2-carboxylic acid (Atc) instead of Phe in the message domain. The peptides were agonists in the subnanomolar range in the MVD assay and in the micromolar or higher range in the GPI assay, showing a very high selectivity for delta receptors. A very similar trend could be observed in radioreceptor binding assays in which selective tritiated opioid ligands were used. (R)- and (S)-Atc-deltoriphins exhibited similar Ki values in the binding assay, with almost complete loss of the stereospecificity of the binding. Conformational studies provided evidence for the little disturbance of the backbone conformational equilibrium when Phe3 is replaced by (S)- or (R)-Atc. The use of the Atc constraint gives additional evidence that, during its interaction with the delta receptor, the side chain of residue 3 adopts the trans conformation at chi 1.

[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.

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.

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.

Dibenz[b,f]azepines, Part 7. Synthesis of new, potentially CNS active dibenz[b,f]azepine derivatives

Reactions of 5-carboxamido-5H-dibenz[b,f]azepines (1a-1d) with glyoxylic acid methylester methyl hemiacetal (GMHA) led to 5-(carboxamido-N-alpha-hydroxy-acetic acid methyl ester)-5H- dibenz[b,f]azepines (2a-2d). The reactions with glycols yielded the oligoethylene glycol derivatives (3,4). The new compounds were screened as anticonvulsants and/or antidepressants (AD).

[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.

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.

[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.

Influence of spatial orientation of the C-6-OH group in ring C of morphine derivatives on opioid activity

The effect of epimerization on agonist and antagonist activities of morphine and dihydromorphine, and those of their N-allyl, -propyl and -cyclopropylmethyl derivatives, were studied in rat tail flick, hot plate and mice hot plate and in isolated guinea-pig ileum assays, respectively. Using the rat tail flick, hot plate and mice hot plate tests, isomorphine and dihydroisomorphine were observed to produce dose-dependent, naloxone-reversible agonist (antinociceptive) actions, in a similar dose range as their parent molecules (relative potencies: 0.6-1.9). Also, these compounds produced agonist activities in isolated tissue preparations in a naloxone-reversible manner. While the N-substituted derivatives of isomorphine and dihydroisomorphine failed to produce antinociceptive activities in the rat tail flick test, they proved to be strong agonists in the guinea-pig ileum experiments, although the Ke values of naloxone were 5-6 times higher against these compounds than against their N-CH3 counterparts. Both the agonist and antagonist activities of the N-cyclopropylmethyl derivatives were found to be most potent in the guinea-pig ileum. The epimerization of morphine and dihydromorphine and their N-substituted derivatives evoked only slight changes in opioid activities in vitro. In vivo, merely the allyl substitution on nitrogen influenced the antagonist activities of epimer pairs. In contrast, substantial changes in opioid profile were observed when N-methyl was replaced by allyl-, propyl- or cyclopropylmethyl. Changes performed this way evoked, on the one hand, an enhancement of the affinities of compounds to mu-receptors, with simultaneous loss of intrinsic efficacy at these receptors, and, on the other hand, promoted the appearance of an agonist profile on a distinct (kappa) opioid receptor.

Age-dependent modification of aspecific cellular effects of the benzodiazepine flunitrazepam

The experiments presented here demonstrate an aspecific effect of the benzodiazepine derivative flunitrazepam (FNZ). It differs in sites and mechanisms of action, both from benzodiazepine (BZ) specific effects on gamma-aminobutyric acid (GABA) blocking transmission via central BZ receptors and from BZ effects mediated by peripheral BZ receptors. The aspecific effect of FNZ can suitably be examined on isolated and identified neurons of the mollusc Lymnaea stagnalis (pond snail). The physiological sites of action are outside the synaptic zone, on the neuron somatic membrane and affect 'intrinsic' properties of membrane, including calcium, calcium-activated potassium and chloride channels. The aspecific FNZ effect exerts an influence on the metabolism of the cell by decreasing the permeability of the calcium channel, diminishing the excitability of the neuron membrane, and hyperpolarizing the cell, thus potentiating the specific effect of FNZ. The senile alterations of the neuron function intensify the aspecific effects of FNZ to such a degree that it must be taken seriously in consideration in anesthesia of elderly patients.

[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.

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.

[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.

[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.