Biomedical subjects

J Nemes

Publications and source records attributed to J Nemes.

At least 19 recordsLinked to original sources

PubMed2003

Load shift of the intervertebral disc after a vertebroplasty: a finite-element study.

Infiltrating osteoporotic cancellous bone with bone cement (vertebroplasty) is a novel surgical procedure to stabilize and prevent osteoporotic vertebral fractures. Short-term clinical and biomechanical results are encouraging; however, so far no reports on long-term results have been published. Our clinical observations suggest that vertebroplasty may induce subsequent fractures in the vertebrae adjacent to the ones augmented. At this point, there is only a limited understanding of what causes these fractures. We have previously hypothesized that adjacent fractures may result from a shift in stiffness and load following rigid augmentation. The purpose of this study is to determine the load shift in a lumbar motion segment following vertebroplasty. A finite-element (FE) model of a lumbar motion segment (L4-L5) was used to quantify and compare the pre- and post-augmentation stiffness and loading (load shift) of the intervertebral (IV) disc adjacent to the augmented vertebra in response to quasi-static compression. The results showed that the rigid cement augmentation underneath the endplates acted as an upright pillar that severely reduced the inward bulge of the endplates of the augmented vertebra. The bulge of the augmented endplate was reduced to 7% of its value before the augmentation, resulting in a stiffening of the IV joint by approximately 17%, and of the whole motion segment by approximately 11%. The IV pressure accordingly increased by approximately 19%, and the inward bulge of the endplate adjacent to the one augmented (L4 inferior) increased considerably, by approximately 17%. This increase of up to 17% in the inward bulge of the endplate adjacent to the one augmented may be the cause of the adjacent fractures.

Biomechanical Phenomena↗

PubMed2003

Material changes in osteoporotic human cancellous bone following infiltration with acrylic bone cement for a vertebral cement augmentation.

Bone cement infiltration can be effective at mechanically augmenting osteoporotic vertebrae. While most published literature describes the gain in mechanical strength of augmented vertebrae, we report the first measurements of viscoelastic material changes of cancellous bone due to cement infiltration. We infiltrated cancellous core specimen harvested from osteoporotic cadaveric spines with acrylic bone cement. Bone specimen before and after cement infiltration were subjected to identical quasi-static and relaxation loading in confined and free compression. Testing data were fitted to a linear viscoelastic model of compressible material and the model parameters for cement, native cancellous bone, and cancellous bone infiltrated (composite) with cement were identified. The fitting demonstrated that the linear viscoelastic model presented in this paper accurately describes the mechanical behaviour of cement and bone, before and after infiltration. Although the composite specimen did not completely adopt the properties of bulk bone cement, the stiffening of cancellous bone due to cement infiltration is considerable. The composite was, for example, 8.5 times stiffer than native bone. The local stiffening of cancellous bone in patients may alter the load transfer of the augmented motion segment and may be the cause of subsequent fractures in the vertebrae adjacent to the ones infiltrated with cement. The material model and parameters in this paper, together with an adequate finite-element model, can be helpful to investigate the load shift, the mechanism for subsequent fractures, and filling patterns for ideal cement infiltration.

Bone Density↗

PubMed2001

[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.

Dental Caries↗

PubMed2001

[Goltz syndrome - a case report].

The Goltz (Goltz-Gorlin) syndrome or focal dermal hypoplasia is a relatively rare disease. Its clinical manifestation shows a great variety. The syndrome characterized by anomalies of cutaneous, osseous, dental and ocular structures. The authors present the case of a six-year-old girl with typical anomalies of Goltz-Gorlin syndrome with special respect to the dental problems.

Abnormalities, Multiple↗

PubMed2001

[Attention deficit hyperactivity disorder. Literature review for the pediatric dentist].

The purpose of this review was to give a complete summary of the ADHD (Attention Deficit Hyperactivity Disorder) for dentists, especially for those who deal with dental traumatology. Children with ADH disorder show symptoms of restlessness, hyperactivity, impulsive behaviour and inattention often resulting in serious dental accidents. The article summarizes the literary data concerning ADH-Syndrome, presents a typical case and also deals with the dental considerations.

Attention Deficit Disorder with Hyperactivity↗

PubMed2001

[Effect of the parents' dental fear on the child's oral health].

There are various factors which influence the oral status, among them the dental fear. Dental anxious individuals are likely to have more missing teeth and fewer filled ones. This study examined the association between dental anxiety and oral health status in parents and indirectly in children. The authors found that there is positive correlation between dental fear and missing teeth in the older generation. These tendency can also be seen in younger ones.

Dental Anxiety↗

PubMed2000

[Oxidative stress and antioxidant defense in alcoholic liver disease and chronic hepatitis C].

In the past decade it became accepted that free radicals, lipid peroxidation and antioxidant defense play a role in various tissues damages, thus in certain liver diseases as well. Since only limited data have been reported concerning the oxidative stress in viral hepatitis, a comparative study was performed in patients (pts) with chronic hepatitis C and alcoholic liver disease. In addition, the effects of a flavonolignan drug silymarin were assessed. 10 pts with chronic hepatitis C, 5 pts with alcoholic hepatitis and 13 pts with alcoholic cirrhosis have been investigated. Biochemical liver tests (serum bilirubin, aminotransferases, ALT, AST, lactate dehydrogenase (LDH), pseudocholinesterase, prothrombin), malandialdehyde (MDA) levels in plasma and red blood cell (RBC) hemolysate, superoxide radical generating capacity of stimulated polymorphonuclear granulocytes (PMN), plasma concentrations of reduced (GSH) and oxidized (GSSG) glutathione, vitamin A, luteine and beta carotene, furthermore RBC superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase activities were determined. The level of plasma MDA--as the marker of lipid peroxidation--was highest in alcoholic cirrhosis (five times of normal) (p < 0.05), the RBC hemolysate MDA was most elevated in chronic hepatitis C (p < 0.05). The mean PMNs' superoxide radical generating capacity was 116.6% of normal control in alcoholic hepatitis, where the mean GSH level was the lowest (89.8% of normal). Plasma vitamin A content was lowest in alcoholic cirrhosis (68% of control) (p < 0.05). SOD activity was elevated in both chronic hepatitis C and alcoholic cirrhosis, where GPx activity was decreased (p < 0.05). There was a correlation between LDH and SOD activities (r = 0.77, p = 0.015). Silymarin treatment of one month duration resulted in normalization of serum bilirubin in 55% of treated pts, AST became normal in 45%, and RBC hemolyzate MDA level normalized in similar rate. A significant increase in both GSH and retinoids was found. Alterations in oxidative stress and antioxidant defense system were shown in chronic hepatitis C, not only in alcoholic liver disease. The parameters of lipid peroxidation and antioxidant defense may be useful surrogate markers for monitoring pts with liver disease during hepatoprotective treatment.

Adult↗

PubMed2000

[Experience with laparoscopic adrenalectomy in 25 cases].

Between July 1997, and April 1999 the authors performed 25 transperitoneal laparoscopic adrenalectomies. Conversion due to bleeding in 3 cases and due to unsuspected malignancy in 1 case was necessary. Complete resection was carried out in 22 cases. In 3 cases where a well circumscribed adenoma was visualized, only enucleation was performed. A new approach for left sided resection was also introduced. In the authors experience laparoscopy is an absolutely suitable intervention for the benign diseases of the adrenal glands. It assures a short, uncomplicated and painless postoperative period for the patients, with the same effectivity and safety compared to the conventional method.

Adrenalectomy↗

PubMed2000

Suprasplenic, transperitoneal approach for laparoscopic adrenalectomy on the left side.

BACKGROUND: There are several minimally invasive means of exposing the adrenal glands. Each of them has its own advantages and disadvantages. A new approach was introduced for laparoscopic adrenalectomy on the left side. PATIENTS AND METHODS: Between June 1997 and January 2000, 23 transperitoneal unilateral laparoscopic adrenalectomies on the left side were performed. In 4 of these cases, only enucleation of a well-circumscribed adenoma was done. In a semilateral position, the gland was approached through the splenophrenic ligament with partial mobilization of the spleen. The left adrenal gland was quickly and safely exposed, thus avoiding the complications of transmesocolic exposure. There was no need for extensive mobilization of the spleen or the pancreas. RESULTS: In 20 cases the laparoscopic operation was successfully performed. In 3 cases conversion was necessary because of bleeding. The estimated blood loss was on average 150 ml. The mean operation time was 84 min, the mean postoperative stay 4.5 days. No other major complications were observed. CONCLUSION: This new method is a safe and quick technique for left-sided laparoscopic adrenalectomy, and it can be an alternative to the existing ones.

Adrenal Gland Diseases↗

PubMed1999

[Function of the central sterilization office at the Semmelweis Clinic of Conservative Dentistry and Prosthodontics].

In order to prevent cross-infection by blood borne and other pathogens central sterilization department has been constructed in the common building of the Depts. of Conservative Dentistry and Prosthodontics. Instrument sterilization is accomplished in six steps: (1) consolidation and transport of instruments, (2) cleaning, (3) packaging, (4) sterilization, (5) storage, (6) sterilizer monitoring. This process is performed by trained sterilization technicians to ensure that attending faculty, student dentists, clinical staff and patients are protected from cross-infection caused by contaminated dental instruments.

Cross Infection↗

PubMed1999

[The role of salivary immunoglobulins (secretory IgA, IgM, IgG) in caries prevalence and primary B-cell deficiency].

The role of salivary immunoglobulins (IgA, IgM, IgG) in caries etiology is not yet clearly known. Our aim was to study whether there might be a connection between the amount of immunoglobulins in the saliva and caries prevalence. It was found that there was a significant difference (p < 0.05 or less) in secretory IgA, IgM, IgG levels, as well as DMF-T, DMF-S (approx) indices between selective IgA deficient, hypogammaglobulinemic, and healthy children, who had primary teeth.

Adolescent↗

PubMed1999

Hemorheological and hemodynamic parameters in patients with essential hypertension and their modification by alpha-1 inhibitor drug treatment.

Hemorheological factors play an important role in the pathogenesis of different cardiovascular diseases. The hemorheological and hemodynamic parameters in essential hypertension and their possible modification by antihypertensive treatment were examined in the following two studies. In the first study the fundus appearance and hemorheological parameters (plasma and whole blood viscosity (WBV), fibrinogen level) of 33 hypertensive patients (mean age: 55 years) were examined. The fundus appearance showed retinopathy in all the cases between stages I-III. All the measured hemorheological parameters of the examined patients were in the pathological range (WBV at 90 s(-1): 5.18 mPa s) and were significantly (p < 0.01) higher than in healthy controls (WBV at 90 s(-1): 4.18 mPa s). The hemorheological factors showed a parallel deterioration with the fundus appearance, namely their values were significantly (p < 0.01) higher in patients with a fundus appearance stage III (WBV at 90 s(-1): 6.02 mPa s) than stage I (WBV at 90 s(-1): 4.51 mPa s). These results show that there is a correlation between hemorheological parameters and fundus appearance in hypertensives, and this suggests that hemorheological factors may play a role in the development of hypertensive retinopathy. In the second study the hemorheological and hemodynamical effects of Doxazosin, a selective alpha-1-adrenoreceptor blocker agent, was examined in twenty patients (mean age: 54 years) with essential hypertension. Hemorheologic (hematocrit, fibrinogen, plasma and whole blood viscosity) and hemodynamic (cardiac output and index, total peripheral resistance) parameters and plasma lipids were determined. The measurements were carried out before the beginning of the treatment, after 1 week and after 12 weeks treatment periods. Besides significant reduction of blood pressure and total peripheral resistance (p < 0.001), a decrease in cholesterol (p < 0.001) and triglycerides (p < 0.01) levels and a beneficial effect on hemorheological parameters was detected. Fibrinogen and plasma viscosity decreased significantly (p < 0.01). Hematocrit value was also lower after one week (p < 0.001), then an increase could be seen. Whole blood viscosity showed similar changes as hematocrit, but the degree of its final increase was slighter, which was supported by the significantly lower value of corrected blood viscosity (p < 0.05). All these findings indicate that hemorheological factors may play a role in the pathogenesis and in the development of organ damages in hypertension.

Adrenergic alpha-Antagonists↗

PubMed1999

Effects of doxazosin on hemorheological, hemodynamic and lipid parameters in patients with essential hypertension.

It is known from previous studies that hemorheological parameters are altered in patients with essential hypertension. The hemorheological and hemodynamical effects of doxazosin, a selective alpha-1-adrenoreceptor blocker agent, was examined in twenty patients (mean age: 54+/-10 years) with essential hypertension. Hemorheologic (hematocrit, fibrinogen, plasma and whole blood viscosity) and hemodynamic (cardiac output and index, total peripheral resistance) parameters and plasma lipids were determined. The measurements were carried out before the beginning of the treatment, after 1 week and after 12 weeks treatment periods. Besides significant reduction of blood pressure and total peripheral resistance (p < 0.001), a decrease in cholesterol (p < 0.001) and triglyceride (p < 0.01) levels and a beneficial effect on hemorheological parameters was detected. Fibrinogen and plasma viscosity decreased significantly (p < 0.01). Hematocrit value was also lower after one week (p < 0.001), then an increase could be seen. Whole blood viscosity showed similar changes as hematocrit, but the degree of its final increase was slighter, which was supported by the significantly lower value of corrected blood viscosity (p < 0.05).

Adult↗

PubMed1998

Reciprocal interactions between human cytomegalovirus and human T cell leukemia-lymphoma virus type I in monocyte-derived macrophages cultured in vitro.

Infection of macrophages with human cytomegalovirus (HCMV) has been shown to be nonlytic and exclusively cell associated. Human T cell leukemia-lymphoma virus type I (HTLV-I) is capable of establishing productive infection in macrophages. We studied the interactions between HCMV and HTLV-I in monocyte-derived macrophages cultured in vitro. We found that coinfection of macrophages with HCMV and HTLV-I significantly enhanced HCMV replication, resulting in release of infectious HCMV from dually infected cells. On the other hand, HCMV inhibited HTLV-I replication in macrophages coinfected with both viruses. Reciprocal interactions between HCMV and HTLV-I were mediated by their trans-acting proteins. Results of transfection studies demonstrated that the tax gene product of HTLV-I alone was capable of upregulating HCMV production. In a transient gene expression assay the immediate-early 2 (IE2) protein of HCMV alone could inhibit HTLV-I replication, whereas the IE1 protein, which had no effect by itself, produced a synergistic inhibitory effect together with the IE2 protein. Results from this study suggest that in vivo double infection of macrophages with HCMV and HTLV-I may contribute to the dissemination of HCMV infection in patients suffering from HTLV-I-associated T cell leukemia-lymphoma.

Antigens, Viral↗

PubMed1997

Epstein-Barr virus permissively infects human syncytiotrophoblasts in vitro and induces replication of human T cell leukemia-lymphoma virus type I in dually infected cells.

Epstein-Barr virus (EBV) and human immunodeficiency virus type 1 (HIV-1), as well as human T-cell leukemia-lymphoma virus type I (HTLV-I), may interact in the pathogenesis of human retroviral infections. The placental syncytiotrophoblast layer represents a barrier protecting the fetal compartment from exposure to retroviruses. We studied the interactions of EBV with HIV-1 and HTLV-I in human term syncytiotrophoblast cells to investigate the significance of double infections in transplacental transmission of human retroviruses. We found that syncytiotrophoblast cells could be productively infected with EBV. Dual infection of the cells with EBV and HTLV-I resulted in full replication cycle of otherwise latent HTLV-I. In contrast, the restricted permissiveness of syncytiotrophoblasts for HIV-1 was not influenced by coinfection of the cells with EBV. Infection of syncytiotrophoblast cells with EBV, but not HTLV-I, induced interleukin-2 and interleukin-6 secretion, and augmented secretion occurred on coinfection with both viruses. Coinfection of syncytiotrophoblast cells with EBV and HTLV-I induced tumor necrosis factor-beta and transforming growth factor-beta 1 secretion, but infection with either virus alone did not lead to secretion of these cytokines. Permissive replication cycle of HTLV-I was induced by the EBV immediate-early gene product Zta. Pseudotype formation between EBV and HTLV-I in coinfected syncytiotrophoblast cells was not found. Our data suggest that activation of HTLV-I gene expression by EBV in coinfected syncytiotrophoblast cells may be a mechanism for transplacental transmission of HTLV-I.

Animals↗

PubMed1997

Two parallel routes of the complement-mediated antibody-dependent enhancement of HIV-1 infection.

OBJECTIVE: To study the mechanism of the complement-mediated antibody-dependent enhancement (C'-ADE) of HIV infection which may play a significant role in the progression of HIV-disease. METHODS: In vitro complement activating and complement-mediated HIV-infection enhancing abilities of three human anti-gp41 monoclonal antibodies (MAb) were tested. C'-ADE was estimated using HIV-1IIIB and CR2 (CD21)-carrying MT-4 target cells. Normal human serum (NHS), purified C1q, C1q-deficient (C1qD) and C2-deficient (C2D) human sera were applied as complement sources. RESULTS: All MAb mediated increased C1q binding to solid-phase gp41. All MAb had a marked dose-dependent and strictly complement-mediated HIV-infection enhancing effect. Mixtures of the MAb with purified C1q also significantly increased HIV-1 infection. C1qD serum had a markedly lower enhancing effect than NHS, which could be raised to normal level by addition of purified C1q. Pretreatment of the target cells with anti-CR2 antibodies only partially inhibited the enhancing effect of the MAb plus normal human serum. CONCLUSION: These novel findings indicate that besides the well-known facilitation of entry of HIV-1 by the interaction between virus-bound C3 fragments and CR2 present on the target cells, fixation of C1q to intact virions also results in an enhanced productive HIV-1 infection in the MT-4 cell cultures.

Antibodies, Monoclonal↗

PubMed1997

[Megakaryocytic thrombopenic purpura associated with enamel hypoplasia].

Patients with platelet disorders usually bleed into superficial sites such as the skin, mucous membranes, genitourinary tract and gastrointestinal tract caused by thrombocytopenia or thrombocyte dysfunction. Thrombocytopenia is caused by one of three mechanisms-decreased marrow production, increased splenic sequestration, or accelerated destruction of platelets. We report a 9-year-old male patient with thrombocytopenic purpura, dyserythropoetic anaemia, freckles on the skin and nanosomia, resembling Fanconi's (constitutional) anaemia. Although many patients with constitutional anaemia own other bony abnormalities, it was not found in this case. On the other hand, the patient showed enamel hypoplasia. To our knowledge, this association has never been reported before. Laboratory diagnosis, clinical findings, dental abnormalities and treatment are presented in details.

Abnormalities, Multiple↗

PubMed1997

The values of detection of free radical mediated reactions in patients.

The peroxidative processes and individual antioxidant protection were measured in patients with different cardiovascular diseases. We concluded that monitoring of this system we were able to detect not only the actual changes of lipid peroxidation and antioxidant defence mechanisms, but additionally the therapeutic efficacy of the treatment.

Adrenergic beta-Antagonists↗