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Biomedical subjects

B Kiss

Publications and source records attributed to B Kiss.

At least 37 records · Page 2Linked to original sources
PubMed2000

Age dependence of perimacular white blood cell flux during isometric exercise.

PURPOSE: To investigate the age dependence of perimacular white blood cell flux (WBCF) during isometric exercise. METHODS: Fourteen healthy young (age range: 21-29 years; 24 +/- 3 years, mean +/- SD, 12 male and 2 female) and 15 healthy middle-aged (age range: 45-57 years; 53 +/- 4 years, mean +/- SD; 5 male and 10 female) volunteers were studied. Subjects performed isometric handgrip for 10 minutes and squatting for 6 minutes. WBCF was assessed with the blue field entoptic technique, mean arterial pressure (MAP) was measured with an automated oscillometric device, intraocular pressure (IOP) was measured by Goldmann applanation tonometry and ocular perfusion pressure (OPP) was calculated as 2/3 MAP - IOP. RESULTS: Baseline WBCF was significantly higher in young subjects than in middle-aged subjects (191 +/- 28 vs 142 +/- 23; p = 0.001). Isometric handgrip induced a significant increase in WBCF in the middle-aged subjects (23 +/- 24%; p = 0.005), but not in the young subjects. Squatting significantly increased WBCF in both groups (young: 42 +/- 23%; p = 0.004 and middle aged: 51 +/- 27%; p < 0.001). A significant deviation from baseline WBCF was observed when OPP increased by 42 +/- 4% (p = 0.003) and 35 +/- 4% (p < 0.001) for the young and middle-aged subjects, respectively. The OPP-WBCF relationship was not different between the two study groups. CONCLUSION: Altered retinal autoregulation as observed in vascular ocular disease appears to be unrelated to the normal physiological aging process.

Adult↗
PubMed2000

Evaluation of the Zeiss retinal vessel analyser.

AIM: To investigate the reproducibility and sensitivity of the Zeiss retinal vessel analyser, a new method for the online determination of retinal vessel diameters in healthy subjects. METHODS: Two model drugs were administered, a peripheral vasoconstrictor (the alpha receptor agonist phenylephrine) and a peripheral vasodilator (the nitric oxide donor sodium nitroprusside) in stepwise increasing doses. Nine healthy young subjects were studied in a placebo controlled double masked three way crossover design. Subjects received intravenous infusions of either placebo or stepwise increasing doses of phenylephrine (0.5, 1, or 2 microg/kg/min) or sodium nitroprusside (0.5, 1, or 2 microg/kg/min). Retinal vessel diameters were measured with the new Zeiss retinal vessel analyser. Retinal leucocyte velocity, flow, and density were measured with the blue field entoptic technique. The reproducibility of measurements was assessed with coefficients of variation and intraclass correlation coefficients. RESULTS: Placebo and phenylephrine did not influence retinal haemodynamics, although the alpha receptor antagonist significantly increased blood pressure. Sodium nitroprusside induced a significant increase in retinal venous and arterial diameters (p<0.001 each), leucocyte density (p=0.001), and leucocyte flow (p=0.024) despite lowering blood pressure to a significant degree. For venous and arterial vessel size measurements short term coefficients of variation were 1.3% and 2.6% and intraclass correlation coefficients were 0.98 and 0.96, respectively. The sensitivity was between 3% and 5% for retinal veins and 5% and 7% for retinal arteries. CONCLUSIONS: These data indicate that the Zeiss retinal vessel analyser is an accurate system for the assessment of retinal diameters in healthy subjects. In addition, nitric oxide appears to have a strong influence on retinal vascular tone.

Adrenergic alpha-Agonists↗
PubMed1999

[Paraneoplastic nephropathy associated with adult renal carcinoma (immunologic and clinicopathologic study)].

Rare "paraneoplastic nephropathies" are associated with a wide variety of human tumors. Little is known about the pathogenetical background. To our knowledge no systematic study about the association of potentially "immunogenic" renal cell cancer (RCC) and "paraneoplastic nephropathy" has been published so far. An immunohistochemical analysis of native kidneys and a nephrological follow up of 60 patients with renal cell cancer (RCC) treated at the Department of Urology, medical University, Pécs (Hungary) between 1993-1998 has been performed. Cellular and humoral immunity was analysed by immunohistochemistry. Clinical/laboratory parameters of the patients with tumor associated nephropathy were pre- and postoperatively registered. Eleven IgA-nephropathy (IgA-NP) and 5 focal segmental glomerulosclerosis (FSGS), manifested in preoperative clinical signs in 11 out of 16 cases were found. Clinical symptoms disappeared in 6 out of 8 IgA-NP patients by tumor nephrectomy in a follow up of 38.7 (18-51) months. Eleven out of 16 tumors were stained with the identical anti human immunoglobulin (IgA or IgM) present in the glomerular immune complexes. The RCC-associated VHL (von Hippel-Lindau) protein was detectable in 3 out of 8 IgA-NP patients as an antigen component of their nephritogenic immune complexes. Tumor infiltrating lymphocytes (TIL) considered as a local sign of cellular tumor immunity were more frequently present in tumors associated with nephropathy than without it (69% vs 25%). Pathogenetic correlation between the tumor immunity in renal cell carcinoma and "paraneoplastic IgA-nephropathy" has been demonstrated in some of the cases. Tumor nephrectomy excluding the need of post-operative single kidney biopsies should be a safe tool in the differential diagnosis of tumor-associated nephrological conditions.

Adenocarcinoma, Clear Cell↗
PubMed1999

Effects of peribulbar anesthesia on ocular blood flow in patients undergoing cataract surgery.

PURPOSE: The effects of extraconal, peribulbar anesthesia on ocular blood flow may be caused by concomitant elevations in intraocular pressure or direct pharmacologic alteration of vascular tone. We quantified the effect on ocular circulation with a new technique for assessment of ocular hemodynamics. METHODS: In a prospective study, ocular hemodynamics were measured before and 1 and 5 minutes after peribulbar anesthesia in 22 eyes with age-related cataract. Measurements included fundus pulsation amplitude with a laser interferometric method assessing the pulsatile choroidal blood flow and mean blood flow velocity as well as resistive index in the ophthalmic and central retinal artery with Doppler sonography. Systemic blood pressure and pulse were monitored throughout the period of ocular hemodynamic measurements. RESULTS: Fundus pulsation amplitude decreased significantly after peribulbar anesthesia (after 1 minute and 5 minutes: -13% and -8%; P < .001). In the central retinal artery, mean blood flow velocity dropped (-15%; P < .001) and resistive index increased (+3%; P = .02) 1 minute after peribulbar anesthesia compared with baseline. There were no changes in ophthalmic artery hemodynamics. Intraocular pressure was elevated 1 minute after peribulbar anesthesia (+29%; P = .003) but reached baseline values after 5 minutes. CONCLUSION: Pulsatile choroidal blood flow and retinal blood flow velocities were reduced after peribulbar anesthesia. These reductions were still present 5 minutes after peribulbar anesthesia, when intraocular pressure had returned to baseline values. This supports the theory of drug-induced vasoconstriction after peribulbar anesthesia. A loss of vision may be a risk of peribulbar anesthesia in patients who have compromised ocular blood flow before surgery.

Adult↗
PubMed1999

Effect of small incision cataract surgery on ocular blood flow in cataract patients.

PURPOSE: To evaluate the effect of small incision cataract surgery using peribulbar anesthesia on ocular blood flow in patients with senile cataract. SETTING: Department of Ophthalmology, University of Vienna, Vienna, Austria. METHODS: In 33 eyes of 33 consecutive patients scheduled for cataract surgery, ocular hemodynamics were measured preoperatively and 1 day, 1 week, and 1 month postoperatively. Measurements included fundus pulsation amplitude (FPA) with a laser interferometric method that assessed the pulsatile choroidal blood flow, mean blood flow velocity (MFV), and resistive index (RI) in the ophthalmic artery (OA) and the central retinal artery (CRA) with Doppler sonography. Systemic hemodynamics and intraocular pressure (IOP) also were measured. RESULTS: The FPA, MFV, and RI in the OA and the CRA did not change postoperatively from baseline values. Systemic hemodynamics, IOP, and as a consequence ocular perfusion pressure, also remained unchanged. CONCLUSION: Uneventful small incision cataract surgery using peribulbar anesthesia did not affect ocular blood flow in patients with senile cataract between 1 day and 1 month postoperatively.

Adult↗
PubMed1999

Acetazolamide-induced cerebral and ocular vasodilation in humans is independent of nitric oxide.

Acetazolamide, a carbonic anhydrase inhibitor, is used orally in the treatment of primary and secondary open-angle glaucoma and induces ocular and cerebral vasodilation. Several in vitro studies have shown that carbonic anhydrase pharmacology and the L-arginine-nitric oxide (NO) pathway are closely related. We investigated the role of NO in acetazolamide-induced vasodilation on cerebral and ocular vessels in 12 healthy subjects in the presence or absence of NG-monomethyl-L-arginine (L-NMMA), a NO synthase inhibitor, and in the presence or absence of L-arginine, the precursor of NO. Acetazolamide was administered after pretreatment with either L-NMMA or placebo and either L-arginine or placebo. Pulsatile choroidal blood flow was assessed with laser interferometric measurement of fundus pulsation. In addition, mean blood flow velocity (MFV) in the middle cerebral artery (MCA) and ophthalmic artery (OA) was measured with Doppler sonography. Acetazolamide increased ocular fundus pulsation amplitude (FPA; +27%, P < 0.001) and MFV in the MCA (+38%, P < 0.001) and in the OA (+19%, P = 0.003). Administration of L-NMMA alone reduced FPA (-21%, P < 0.001) and MFV in the MCA (-11%, P = 0. 030) but did not change MFV in the OA. All hemodynamic effects of L-NMMA were reversed by L-arginine. However, neither L-NMMA nor L-arginine altered acetazolamide-induced changes in cerebral or ocular hemodynamic parameters. The present data indicate that acetazolamide-induced hemodynamic changes are not mediated by NO. Which mediators other than NO are involved in the hemodynamic effects as induced by carbonic anhydrase inhibitors remains to be elucidated.

Acetazolamide↗
PubMed1999

Renal cell carcinoma and paraneoplastic IgA nephropathy.

Paraneoplastic nephropathy is rarely associated with human tumors. Little is known about the pathogenetic background of this relationship. To our knowledge, no conclusive study of the association of potentially 'immunogenic' renal cell carcinoma (RCC) and paraneoplastic nephropathy has been published. For this reason, we performed an immunohistochemical analysis of native resected kidneys of 60 patients with RCC, paying special attention to their pre- and postoperative records. Sixteen (27%) of the 60 tumor patients had immune complex nephropathy (11 IgA nephropathy [IgA NP] and 5 focal segmental glomerulosclerosis [FSGS]). Preoperative proteinuria and/or hematuria observed in 11 of 16 cases disappeared in 6 IgA NP patients within a 2- to 3-month follow-up after nephrectomy. Eleven of 16 tumors stained with the anti human immunoglobulin (IgA or IgM) of the same isotype as that present in glomerular immune complexes. In 3 IgA NP patients RCC-associated von Hippel-Lindau (VHL) protein and IgA staining were found simultaneously in the tumor and glomeruli, with the clinical and laboratory findings disappearing after nephrectomy. Immune injury of the glomeruli due to a tumor-induced antigen-antibody response was demonstrated in these 3 IgA NP patients.

Adult↗
PubMed1999

The value of Asamura-Naruke type main bronchus stump closure and pleuro-pericardial flap covering by own method to avoid broncho-pleural fistula (BPF).

1. Authors present an "old-new" main bronchus closure procedure, which combines the Sweet's and Overholt's methods, recommended by Asamura-Naruke. 2. The A-N procedure decreased the prevalence of BPF from 2.8% to 0.09% in case of thoracotomy and from 9.5% to 2.4% in case of pneumonectomy compared 2 different stump-closing types. 3. There was not BPF in the "covered subgroup" (0%/92 PN) recommended by us, independent of the closing types. 4. All bronchial stumps closed like A-N and covered by our method (0% BPF/62 PN) healed.

Bronchi↗
PubMed1999

Video-assisted thoracoscopic pleurodesis for malignant pleural effusions.

AIM: The objective was to analyse the efficiency, and safety of thoracoscopic pleurodesis (TP). A retrospective study was made of an initial series of 75 patients undergoing lifetime follow-up who received TP in our department for the treatment of malignant pleural effusions (MPE). MATERIAL AND METHODS: From May 1994 to December 1998, 34 men and 41 women with a median age of 63.4 +/- 12.5 years were treated by TP. We performed 36 partial diathermic abrasions on pleura combined with talc insufflation, and in 39 cases only talc poudrage. The mean duration of insention of the chest tube was 4.1 (range 2 to 17) days, with 8.4 (range 5 to 20) days of postoperative hospitalization. There were no severe intraoperative or postoperative complications. The 30-day mortality rate was 1.3% (1 case). The period of follow-up ranged from 2.5 to 40 months (average 6.8). No case of late recurrence has been observed to date. CONCLUSION: Videothoracoscopic pleurodesis (talc poudrage) as a simple and efficient procedure seems to be the best alternative treatment regimen for the management of MPE in a group of selected patients.

Adult↗
PubMed1998

Effect of RGH-2716 on learning and memory deficits of young and aged rats in water-labyrinth.

RGH-2716 is a novel 1-oxa-3,8-diazaspiro[4.5] decan 2-one, which was published to have potent inhibitory effect on neuronal Na and Ca movement and stimulatory action on nerve growth factor (NGF)-production, as well as to show significant antiamnesic activity in experimental amnesia models. The aim of the present experiments was to study the effect of the compound on the learning process and on the different stages of memory using water-labyrinth in normal and memory impaired young animals, as well as to study cognitive effect of RGH-2716 on aged animals. At the doses of 0.5 mg/kg i.p. or 3 mg/kg p.o. given before daily swimming, this compound improved the learning process of young animals impaired by either diazepam (DIA) or scopolamine (SCOP). In retrograde amnesia model RGH-2716 (3 mg/kg p.o.) significantly ameliorated consolidation process and retrieval of information impaired by SCOP or DIA. Nimodipine and vinpocetine (10 mg/kg p.o.) showed moderate effect compared to RGH-2716. Aged rats pretreated with daily i.p. RGH-2716 performed the tasks with significantly fewer errors and shorter swimming time than untreated aged rats. When aged animals had to solve a new labyrinth problem, treated aged rats showed significantly better learning ability than aged controls. One month of oral treatment of aged rats with 3 mg/kg dose of RGH-2716 two times daily resulted in a "tendency-like" improvement in learning of aged Fischer 344 and spontaneously hypertensive (SH) rats. The present results make RGH-2716 an interesting compound for the treatment of cognitive disorders.

Aging↗
PubMed1996

[Mechanism of action of vinpocetine].

Cavinton was introduced into the clinical practice some twenty years ago in Hungary for the treatment of cerebrovascular disorders and related symptoms. Since then, its active ingredient, vinpocetine, beside its therapeutical utilization, has become a reference compound in the pharmacological research of cognitive deficits caused by hypoxia and ischaemia as well as in the cellular and biochemical investigations related to cyclic nucleotides. In this review a survey is given on the experimental data obtained with vinpocetine and an attempt is made to outline the drug's mechanism of action. Early experiments with vinpocetine indicated five main pharmacological and biochemical actions: (1) selective enhancement of the brain circulation and oxygen utilization without significant alteration in parameters of systemic circulation, (2) increased tolerance of the brain toward hypoxia and ischemia, (3) anticonvulsant activity, (4) inhibitory effect on phosphodiesterase (PDE) enzyme and (5) improvement of rheological properties of the blood and inhibition of aggregation of thrombocytes. Later studies in various laboratories confirmed the above effects and clearly demonstrated that vinpocetine offers significant and direct neuroprotection both under in vitro and in vivo conditions. Evidence has been obtained that neuroprotective action vinpocetine is related to the inhibition of operation of voltage dependent neuronal Na(+)-channels, indirect inhibition of some molecular cascades initiated by the rise of intracellular Ca(2+)-levels and, to a lesser extent, inhibition of adenosine reuptake. Vinpocetine has been shown to be selective inhibitor of Ca(2+)-calmodulin dependent cGMP-PDE. It is assumed that this inhibition enhances intracellular a GMP levels in the vascular smooth muscle leading to reduced resistance of cerebral vessels and increase of cerebral flow. This effect might also beneficially contribute to the neuroprotective action.

Animals↗
PubMed1995

[Echocardiographic diagnosis of intermittent failure of a mitral valve prosthesis].

Three cases are reported who had intermittent diastolic jamming of a mitral tilting disc valve. The clinical presentation of this unfrequent but catastrophic early postoperative complication was different in all cases: the first patient presented with heart failure, the third patient had loss of consciousness with enuresis and the second patient was asymptomatic at the time of the diagnosis. Electromechanical dissociation was first suspected by clinical examination in 2 cases but it was confirmed in all 3 cases by 2 dimensional and Doppler echocardiography. Transesophageal echocardiography did not provide any additional information. Besides opening failure of the valve Doppler echocardiography also demonstrated incomplete or delayed opening in the asymptomatic period. Survival is dependent on correct diagnosis and urgent surgical treatment of this type of prosthetic valve dysfunction.

Echocardiography, Doppler↗
PubMed1995

Quantification of crystal growth of calcium oxalate in gel and its modification by urinary constituents in a new flow model of crystallization.

PURPOSE: To use a new flow model of crystallization to quantify the growth of calcium oxalate monohydrate (COM) in a gel matrix under simulated physiological conditions. MATERIALS AND METHODS: Artificial urine supersaturated in COM was conducted through channels containing a gel with COM seed crystals (flow rate: 0.5 ml. per minute; reaction time: 4 hours; 37 +/- 1C). A relative crystal growth parameter, Vcr, was quantified by discontinuous measurement of scattered light intensity by microphotometry. The effects on Vcr of varying a series of urinary parameters were investigated within the system. RESULTS: The following order of effectiveness in changing COM growth could be derived: dilution > oxalate > calcium > magnesium approximately citrate. CONCLUSIONS: Drinking therapy and lowering of urinary oxalate excretion can be concluded to be the most promising means of preventing CaOx urolithiasis. The new crystallization model demonstrated here should be suitable to new applications in the investigation of urinary stone formation.

Calcium Oxalate↗
PubMed1994

An induced extracellular matrix protein reverses the polarity of band 3 in intercalated epithelial cells.

The intercalated epithelial cell exists in two interconvertible forms in vivo, one where band 3 protein is apical and the other where it is basolateral. We seeded an immortalized clone of these cells at low density and found that band 3 was apical at confluence. There was little or no apical endocytosis. But when the cells were plated at high density, band 3 was basolateral, and there was vigorous apical endocytosis. Extracellular matrix produced by high density cells was able to retarget band 3 in low density cells and to induce apical endocytosis, as did a 230 kd protein partially purified from this matrix. Therefore, polarized targeting of some proteins is determined by external cues that might determine their polarity by reorganizing the cytoplasm.

Animals↗
PubMed1994

Inhibitors of lipid peroxidation among new pyrimido[1',6':1,2]pyrido[3,4-b]indoles.

A series of potent inhibitors of NADPH- and Fe(2+)-dependent lipid peroxidation has been found among new pyrimido[1'6':1,2]pyrido[3,4-b]indole derivatives. According to preliminary structure-activity relationship analysis the saturated pyrimidine moiety was responsible for this effect. Some members of this family were effective in a bilateral carotid occlusion model in mice, and some derivatives showed protective effect in a mouse head injury model.

Animals↗
PubMed1992

Intravenous "pulse" cyclophosphamide therapy of crescentic glomerulonephritis.

Pulse steroids and monthly intravenous cyclophosphamide with a rapid steroid taper were used to treat seven patients with crescentic glomerulonephritis. Despite major impairment of renal function, all patients had a marked improvement in GFR by six months and improvement in proteinuria occurred in six of the seven patients. Two patients were able to discontinue dialysis. The doses of steroids and cyclophosphamide used were less than in comparable studies and side-effects of therapy were minimal. Repeat renal biopsies at over one year demonstrated marked glomerulosclerosis despite relatively stable renal function. Histologic analysis of total glomerular involvement indices on serial biopsies suggested no recruitment of new glomeruli into the crescenteric process once treatment had been initiated. Thus, intravenous pulse cyclophosphamide with pulse steroid therapy appears to be a safe and effective initial therapy for some patients with RPGN. Significant glomerulosclerosis on repeat biopsies suggests that glomerulosclerosis may be predetermined by the initial degree of irreversible glomerular damage and that the long-term course of the disease remains guarded.

Adult↗
PubMed1991

Vinpocetine preferentially antagonizes quisqualate/AMPA receptor responses: evidence from release and ligand binding studies.

The effect of vinpocetine on excitatory amino acid receptors was examined in the rat brain by two different biochemical approaches. In release experiments with striatal slices, vinpocetine reduced the efflux of dopamine and acetylcholine evoked by glutamate, quisqualate and N-methyl-D-aspartate (NMDA), but not that evoked by kainate. In binding experiments with cortical membranes, vinpocetine reduced the binding of [3H]2-amino-3-3-hydroxy-s-methylisoxasole-4-yl-propionic acid ([3H]AMPA), a quisqualate partial agonist, in an incomplete manner, but failed to influence the binding of [3H]kainate and [3H]3-(2-carboxypyperazine-4-yl)-propyl-1-phosphonic acid ([3H]CPP), an NMDA agonist. These findings suggest that vinpocetine is a quisqualate/AMPA antagonist of some specificity and selectivity.

Acetylcholine↗