Showing papers by "University of Zagreb published in 1990"

Developmental history of the transient subplate zone in the visual and somatosensory cortex of the macaque monkey and human brain

Abstract: The cytological organization and the timetable of emergence and dissolution of the transient subplate zone subjacent to the developing visual and somatosensory cortex were studied in a series of human and monkey fetal brains. Cerebral walls processed with Nissl, Golgi, electron-microscopic, and histochemical methods show that this zone consists of migratory and postmigratory neurons, growth cones, loosely arranged axons, dendrites, synapses, and glial cells. In both species the subplate zone becomes visible at the beginning of the mid-third of gestation as a cell-poor/fiber-rich layer situated between the intermediate zone and the developing cortical plate. The subplate zone appears earlier in the somatosensory than in the visual area and reaches maximal width at the beginning of the last third of gestation in both regions. At the peak of its size the ratio between the width of the subplate zone and cortical plate in the somatosensory cortex is 2:1 in monkey and 4:1 in man while in the occipital lobe these structures have about equal width in both species. The dissolution of the subplate zone begins during the last third of gestation with degeneration of some subplate neurons and the relocation of fiber terminals into the cortex. The subplate zone disappears faster in the visual than in the somatosensory area. The present results together with our previous findings support the hypothesis that the subplate zone may serve as a “waiting” compartment for transient cellular interactions and a substrate for competition, segregation, and growth of afferents originated sequentially from the brain stem, basal forebrain, thalamus, and from the ipsi- and contralateral cerebral hemisphere. After a variable and partially overlapping time period, these fibers enter the cortical plate while the subplate zone disappears leaving only a vestige of cells scattered throughout the subcortical white matter. A comparison between species indicates that the size and duration of the subplate zone increases during mammalian evolution and culminates in human fetuses concomitantly with an enlargement of cortico-cortical fiber systems. The regional difference in the size, pattern, and resolution of the subplate zone correlates also with the pattern of cerebral convolutions. Our findings indicate that, contrary to prevailing notions, the subplate may not be a vestige of the phylogenetically old network but a transient embryonic structure that expanded during evolution to subserve the increasing number of its connections.

Neuronal development in human prefrontal cortex in prenatal and postnatal stages.

Abstract: Publisher Summary The mammalian cerebral cortex is organized in a complex way. Important histogenetic processes that lead to its formation are the proliferation, migration, and differentiation of neurons and glial cells, the growth of afferent and efferent fibers, synaptogenesis, and the elimination of certain cells and axonal collaterals. This chapter discusses the neuronal development in human prefrontal cortex in prenatal and postnatal stages. The neurons destined for the primate cerebral cortex originate prenatally in the germinal zones of the fetal telencephalic wall. The prenatal, perinatal, and postnatal dendritic and axonal (neuronal) development in the human PFC (prefrontal cortex) is traced through six different periods on the basis of data on changes in cortical histogenetic events. Period one represents the onset of dendritic differentiation of pyramidal neurons in the cortical plate (CP). Period two denotes late fetal or preterm infant period. Period three represents postnatal year––neonatal period and infancy. Period four is the second postnatal year, known as “early childhood period.” Period five is the period of childhood and adolescence, whereas period six represents the period of adult morphology.

Transvaginal color Doppler imaging.

Abstract: Transvaginal color Doppler was used to assess circulation in pelvic vessels in a group of 64 patients including 15 patients with fertility problems, 18 patients with pelvic tumors, 2 cases of suspected ectopic pregnancy, and 29 pregnant patients with fetuses between 6 weeks and 10 weeks, menstrual age. Blood flow was successfully displayed by color Doppler in the external and internal iliac arteries, and the uterine arteries, but flow in ovarian arteries could not be visualized. In the subgroup of patients with pelvic tumors, neovascularization of tumor tissue was documented in 6 out of 10 cases of uterine fibroma and in 2 cases of ovarian cancer. In 6 cases involving benign ovarian pathology, no abnormal blood supply was observed. A comparison between the characteristics of blood flow within uterine fibromas and ovarian malignancies showed lower impedance and higher blood velocity in cases of malignancy. In early pregnancy blood flow in the umbilical artery could be visualized by color Doppler starting from the 6th week and flow in the aorta from the 8th week. Flow in the trophoblasts was observed with an overall success rate of 59% and successfully demonstrated in 1 out of 2 cases of ectopic pregnancy.

Stress fractures in figure skaters.

Abstract: In 1987, during two great skating contests--the Universiade in the Tatra Mountains and the Gold Pirouette in Zagreb--a total of 42 world class skaters were asked through a questionnaire if they had ever in their career suffered from a stress fracture. Of the 42 skaters, 9 had stress fractures. Four stress fractures occurred during preseason training (two fibular, one second metatarsal, and two fourth metatarsal stress fractures). Increased mileage was reported by three skaters and the fourth had done too much speed training on hills. Five stress fractures occurred during the season (one tibial and two tarsal navicular stress fractures and two stress fractures of the base of the fifth metatarsal). In all cases, the fracture occurred in the take-off leg. All of the subjects were competitive figure skaters with a daily training period of 3 to 8 hours, six times a week. The time from the onset of symptoms to definite diagnosis ranged from 2 to 10 weeks. Of the nine injured skaters, eight were treated conservatively and one skater with Jones' fracture was treated surgically. All of the skaters were able to resume a preinjury level of activity 3 to 7 months after treatment began. In conclusion, it may be emphasized that stress fractures in figure skaters are not rare and should, therefore, always be considered as a possibility.

Respiratory symptoms and lung function in hemp workers.

Abstract: Respiratory symptoms and abnormalities of lung function were studied in 84 female and 27 male hemp workers employed in two textile mills (A and B) processing soft hemp (C sativa). In mill A 46 women and 27 men were investigated and 38 female workers were studied in mill B. Forty nine women and 30 men from a non-dusty industry served as controls. A significantly higher prevalence of almost all chronic respiratory symptoms was found in female hemp workers when compared to control workers. Among the men these differences were significant for nasal catarrh and sinusitis. A high prevalence of byssinosis was found among female hemp workers in both mills (group A, 47.8%; group B, 57.9%) as well as in the male workers (66.7%). Statistically significant across shift reductions in lung function were found for all ventilatory capacity measurements in female and male hemp workers varying from 7.1% for forced expiratory volume in one second (FEV1) to 15.1% for flow rates at 50% vital capacity (FEF50). Measured Monday baseline values before the work shift were significantly lower than expected for hemp workers, being particularly reduced for FEF25 and FEF50. The data suggest that occupational exposure to hemp dust is a significant risk factor for the development of acute and chronic lung disease in workers employed in this textile industry.

The assessment of luteal blood flow in pregnant and non-pregnant women by transvaginal color Doppler.

Abstract: Transvaginal color Doppler of luteal flow was performed on 58 patients with normal early pregnancy before artificial abortion, 73 patients with proven ectopic pregnancy and 75 non-gravid patients in luteal part of menstrual cycle. The equipment used were Aloka Color Doppler SSD-350 and SSD-680 with a 5 MHz transvaginal probe. Obtained color flow from ovarian tissue was explored with pulsed Doppler and the Pourcelot resistance index was calculated. Typical luteal low-impedance flow was detected in 82.8% cases of early pregnancy, 80.8% cases of ectopic pregnancy and 69.3% cases of non-pregnant women. The lowest resistance index (RI = 0.42 +/- 9.12) of luteal flow was found in cases of non-pregnant women, and the highest resistance index (RI = 0.53 +/- 0.09) was obtained in cases of early normotopic pregnancy. RI in cases of ectopic pregnancy was 0.48 +/- 0.07. Statistical analysis has shown significantly different RI in each of 3 groups of patients (P greater than 0.001). Corpus luteum was seen as early as a few days after ovulation in non-pregnant women and was present until about the 11th week of amenorrhea in pregnant women. In 86.4% patients with proven ectopic pregnancy, luteal flow was detected on the same side as the ectopic pregnancy. Our results have shown different RI value of corpus luteum flow in different groups of patients. Such findings could help to exclude pregnancy, specially with non-specific B-mode ultrasound features. Corpus luteum flow could be used as a guide for searching for ectopic pregnancy.

Comparison of chromosome aberration and micronucleus induction in human lymphocytes after occupational exposure to vinyl chloride monomer and microwave radiation.

Abstract: Differences and similarities between the mutagenicity of microwave radiation and VCM were studied on the lymphocytes of persons occupationally exposed to either of these two clastogens. The results of the micronucleus test and the chromosome aberration assay were compared. Our findings provided evidence that the mutagenicity of both VCM and microwave radiation can be detected with both of these tests. However, we detected both quantitative and qualitative differences between VCM and microwave radiation in the induction of aberrations and micronuclei. VCM causes quantitatively more chromosome damage but less dicentric and ring chromosomes than microwave radiation. Anaphase bridges are constantly present in the cultured lymphocytes of VCM-exposed persons but they are rarely seen in the lymphocytes of persons exposed to microwave radiation. The number of micronuclei per a certain number of aberrations is much higher in persons exposed to VCM than in those exposed to microwave radiation. An attempt was made here to point out the main differences in the clastogenic action of a physical and a chemical agent. Such data can be fundamental for better understanding of the genetic effects which derive from mutal action of chemical and physical clastogens.

X-ray diffraction and Mössbauer spectra of the system Fe2O3-SnO2

Abstract: The influence of gallium substitution on the chemical and structural properties of haematite, α-Fe2O3, has been studied using X-ray diffraction and57Fe Mossbauer spectroscopy. The presence of only α-(Ga x Fe1−x)2O3 phase is detected for the compositions withx between 0.01 and 0.90. A gradual decrease of the unit-cell parameters of α-(Ga x Fe1−x)2O3 with the increase of gallium substitution is measured.57Fe Mossbauer spectra showed that the value of the magnetic hyperfine field of pure α-Fe2O3 decreases with increasing gallium for iron substitution. The hyperfine magnetic structure, which is observed for α-(Ga x Fe1−x)2O3 at room temperature, collapsed for the composition withx≃0.50. The changes in the57Fe Mossbauer spectra of the α-(Ga x Fe1−x)2O3 phase are discussed in the sense of the electronic relaxation and the superparamagnetic effects.

Sex steroid receptors in intracranial tumors.

Abstract: Estrogen (ER), progestin (PGR), and androgen (AR) receptors were assayed in cytosols prepared from 38 various intracranial tumors. The receptors were in the following proportions (number of receptor-positive/number of tumors examined): meningiomas were positive for PGR (4/6) and AR (2/5); glioblastomas were also positive for PGR (3/21) and AR (7/21); astrocytomas were positive only for PGR (4/5); and oligodendrogliomas only for AR. In two hamartomas AR was present, while in one chordoma both PGR and AR were present. In this latter tumor ER were not assayed due to insufficient material. The receptors were present in concentrations between 10 and 20 fmol/mg protein. Exceptions were two meningiomas and a chordoma with a high concentration of PGR and AR. Our results support the notion that a proportion of intracranial tumors contains sex steroid receptors, and some of these tumors might be hormonally dependent.

Influence of the degree of liver failure on portal blood flow in patients with liver cirrhosis.

Abstract: Portal vein haemodynamics as demonstrated by the pulsed Doppler system were studied in 37 patients with cirrhosis who had been classified in three groups (A, B, and C) in accordance with the degree of liver failure. Maximal inner diameter of the portal vein was significantly lower in patients who were considered to be in good condition (group A) than in patients with moderate and severe liver failure (group B and group C) (p < 0.001). A significant difference was also found between group A and group B and between group A and group C with regard to the portal blood velocity and portal blood flow (p < 0.001). In accordance with the presence and size of the oesophageal varices, in patients with large varices the portal blood velocity and portal blood flow were significantly lower than in patients without varices (p < 0.001). whereas maximal inner portal vein diameter was significantly higher (p < 0.001). This study demonstrated that in patients with cirrhosis circulatory alterations in the portal vascular be...

Direct evidence for a very large penetration depth in superconducting Bi2Sr2CaCu2O8 single crystals

Abstract: THE temperature-dependent magnetic penetration depth λ(T) and the superconducting coherence length ξ(T) are the two fundamental lengths in superconductivity1, and it is clearly important to determine these two quantities in the new high-transition-temperature (high-Tc) oxide superconductors2. Here we report a direct determination of λ(0) for high-quality single crystals of Bi2Sr2CaCu2O8 with a Tc of 85 K, for the particular case in which the screening currents responsible for the diamagnetism flow perpendicular to the CuO2 planes. The measured value, λc(0) = 100 ± 10 (μm, is surprisingly large, but it is consistent with the anisotropy in the electrical resistivity above Tc, measured on the same batch of single crystals, and approximately consistent with the anisotropy in lower critical field, Hc1 measured by others3. Such a large value may have important consequences for the physical properties of polycrystalline samples and thin films.

Frequency of idiopathic aseptic necrosis in medically treated alcoholics.

Abstract: The occurrence of idiopathic aseptic necrosis of bone in multiple sites has been studied in persons who have had medical treatment for excessive consumption of alcohol. The incidence was 5.3% in 1157 such persons and there were 92 different sites in 62 patients. There were 82 lesions affecting the femoral head, 46 in the left hip and 36 in the right. In 10, it was present in the head of the humerus. Multiple foci were found in 6.1% of patients with the disease. In 2 men and 2 women both femoral heads and both humeral heads were affected. In 2 men the necrosis was present in both humeral heads and the head of the right femur.

Brain gangliosides in Alzheimer's disease.

Abstract: The results demonstrated a statistically significant decrease of ganglio-series gangliosides (GTlb, GDlb, GDla, GMl, nmol lipid-bound sialic acid/mg DNA) in frontal and temporal cortex and basal telencephalon of brains with Alzheimer's disease (AD) in comparison to control brains (P less than 0.05). In addition, frontal and parietal cortex also showed somewhat elevated concentrations of simple gangliosides (GM2, GM3, GM4). Changes in gangliosides in seven regions of human brains with AD analyzed, except of the temporal cortex, did not significantly differ in the "a"/"b" ratio (GDla + GMl/GDlb + GTlb) of ganglioside composition in comparison to control brains. In temporal cortex, an decrease of "a"/"b" ratio on the accounts of more decreased GDla and GMl than GDlb and GTlb was found. A decreased concentration of ganglio-series gangliosides in AD probably correlates with degeneration of cortical neurons. However, elevation of simple gangliosides in frontal and parietal cortex might correlate with an accelerated lysosomal degradation of gangliosides and/or astrogliosis occurring during neuronal death.

The assessment of abnormal pelvic blood flow by transvaginal color and pulsed Doppler

Abstract: Transvaginal color Doppler was used to analyze a group of 19 healthy, 48 infertile and 8 postmenopausal women; 67 patients with uterine and 151 patients with adnexal masses, and 19 patients with a suspected ectopic pregnancy. The ultrasonographer had not been informed of other clinical findings and indications for operative treatment. A 5 MHz transvaginal color Doppler probe was used to visualize the pelvic anatomy and blood flow. Each arterial blood flow velocity was classified into either of two types. In the normal flow pattern, the diastolic flow component was absent or small and the value of resistance index (RI) was >0.50. In the abnormal flow pattern, a large diastolic flow component was evident and the value of RI was

Composition of the essential oils of some Thymus and Thymbra species.

Abstract: A comparative study of some Thymus and Thymbra species growing wild in Yugoslavia, was carried out in order to determine the possibilities of using regional resources of medicinal plants. The essential oil contents (0.70–1.60% vol./dry wt) were determined by hydrodistillation, and the oil compositions analysed by gas chromatography. The oil of Thymus glabrescens Willd. contained 29% 1, 8-cineole, 0.2% thymol and 2% carvacrol. Oil samples of Thymus pulegioides L. contained less than 0.7% 1, 8-cineole, but 6–15% p-cymene, 1–22% thymol and 10–30% carvacrol, while one of these samples consisted of 50% linalol. In the oil of Thymus longicaulis C. Presl, the main components were p-cymene (26%), thymol (40%) and carvacrol (8%). The oil of Thymbra capitata (L.) Cav. [ = Coridothymus capitatus (L.) Rchb. f.] was characterized by large amounts of carvacrol (76–83%).

The Association Between Palatal Grooves in Upper Incisors and Periodontal Complications

Abstract: Palatal groove is a rare morphological defect of upper incisors, frequently associated with localized destruction of periodontal tissue with endodontic complications. In this study, a sample of 1,081 male, young adult subjects, aged 20 to 22, palatal grooving was recorded in 11 (1.01%) subjects, affecting 15 incisors. Among 634 adult subjects, aged 35 to 50, with periodontal disease, palatal groove was found in 5 (0.79%) incisors. Second incisors were more frequently (75%) associated with this anomaly. In the young adults, the mean probing pocket depth in the groove region and around other teeth of the intercanine area was 3.8 mm and 1.2 mm, respectively. In the group of periodontal patients, the mean probing pocket depth was significantly greater at the site of palatal groove (8.8 mm vs. 4.0 mm).

Quantum chaos for exact and broken K quantum number in the interacting-boson model.

Abstract: We show that the exact {ital K} quantum number in the SU(3) limit of the interacting-boson model has a strong effect on the fluctuation properties: Pure sequences of a single {ital K} value have {Delta}{sub 3} statistic close to the Gaussian overlap ensemble prediction while mixed sequences with combined {ital K} values are removed far from the Gaussian overlap ensemble because of {ital K} degeneracy, exceeding even the Poisson-ensemble prediction. Applying the extended interacting boson model to the realistic case of {sup 164}Er nucleus, we have demonstrated that weak breaking of the {ital K} quantum number introduces a very rapid change in fluctuation properties towards those of a pure sequence.

Mills-nixon effect in benzocyclobutenes

Abstract: The structural features of benzocyclobutenes were studied using several semiempirical and ab initio techniques. Qualitative hybridization arguments and actual 6–31 G Hartree-Fock calculations show conclusively that benzocyclobutenes exhibit a typical Mills-Nixon effect which is most pronounced in benzo[1,2:3,4:5,6]tricyclobutene. It is concluded that the experimental X-ray structure of the perfluoro derivative of the latter compound is seriously in error.

Transvaginal colour Doppler ultrasound in normal and abnormal early pregnancy.

Abstract: The value of transvaginal colour and pulse wave Doppler in the diagnosis of pathologic early intrauterine and tubal pregnancy was assessed. Forty-one normal pregnancies, 6 blighted ovum, 6 missed abortions, and 22 suspected ectopic pregnancies (13 proven tubal pregnancies) were examined. Single 5 MHz transvaginal colour and pulse wave Doppler probe was used and once clear signals from uterine vessels, umbilical artery or trophoblastic vessels were obtained. Resistance Index (peak systole--end diastole/peak systole, RI) from the corresponding waveforms was calculated. In 41 normal pregnancies (examined before termination of pregnancy) with gestational age ranged from 6 to 10 weeks mean RI in uterine artery was 0.81 (SD 0.06), in the umbilical artery 1 (SD 0), and 0.48 (0.08) in the trophoblastic vessels. Mean RI from uterine arteries in six pregnancies with blighted ovum and six with missed abortion were 0.77 (SD 0.11) and 0.69 (SD 0.13) respectively. In 2 out of 6 cases of blighted ovum and 4 out of 6 cases of missed abortion flow in trophoblastic vessels could not be detected. These findings suggest ineffective early placentation in pathologic pregnancy. Twenty-two patients with suspected ectopic pregnancy (raised serum beta HCG with empty uterus, amenorrhoea with abdominal pain and/or palpable abdominal mass) were examined. In 13 cases tubal pregnancy was confirmed by laparoscopy and/or laparotomy. In the remaining nine cases the diagnosis was excluded by means of laparoscopy or subsequent negative beta HCG. Doppler diagnosis of ectopic pregnancy was made when colour flow in adnexa with RI less than 0.56 was revealed.(ABSTRACT TRUNCATED AT 250 WORDS)

Limb lengthening and three-dimensional deformity corrections. A retrospective clinical study.

Abstract: Different methods of limb lengthening as used at the Orthopedic Surgery Clinic of the Medical School, University of Zagreb, are compared. The results of operations performed between 1979 and 1989 on 111 patients are presented. These patients were subjected to surgery aimed at length equalization of limbs and/or correction of three-dimensional deformities. Lengthening was performed in 104 patients at one level, and in 7 patients at two levels of the same limb for a total of 118 procedures. In order to compare limb lengthening techniques the patients were divided into four groups: group I, original Wagner technique (45 patients); group II, Wagner technique using corticotomy (33 patients); group III, original Ilizarov technique (35 patients); group IV, continuous lengthening (2 patients). The evaluation covered radiological aspects of regenerated bone, complications and basic lengthening parameters. The results indicate that corticotomy has considerable advantages over osteotomy, provided bone circulation is maintained. These advantages manifest themselves in a reduced number of operations, lower incidence of infection and improved bone regeneration. It is preferable to perform corticotomy at the metaphysis site because of its optimum blood supply and its higher potential for osteogenesis. With corticotomy performed at the diaphysis site, satisfactory results were observed in only one-third of the cases.

Design of linear phase FIR notch filters

Abstract: This paper investigates some approaches for designing one-dimensional linear phase finite-duration impulse-responses (FIR) notch filters, which are based on the modification of several established design techniques of linear phase FIR band-selective filters Based on extensive design examples and theoretical analysis, formulae have been developed for estimating the length of a linear phase FIR notch filter meeting the given specifications In addition, the design of two-dimensional linear phase FIR notch filters is briefly considered Illustrative examples are included