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Biomedical subjects

S Balkan

Publications and source records attributed to S Balkan.

15 recordsLinked to original sources
PubMed2006

Orthostatic heart rate variability analysis in idiopathic Parkinson's disease.

OBJECTIVES: We evaluated time and spectral analyses of 24-h heart rate variability (HRV) and the heart rate responses to passive tilt in patients with idiopathic Parkinson's disease (IPD) in order to investigate cardiovascular autonomic functions. MATERIAL AND METHODS: Twenty-three subjects with IPD without autonomic symptoms and 15 age-matched healthy controls were enrolled. Frequency- and time-domain HRV parameters were studied during resting and passive head-up tilt (HUT) test. RESULTS: All time-domain parameters were found to be low in patients with IPD. In patients with IPD, both low frequency (LF) and high frequency (HF) decreased during HUT period and no significant change in LF to HF ratio was noted. Both time- and frequency-domain HRV indices showed no correlation with age, disease severity and duration, and with l-dopa medication. CONCLUSION: The results indicate that impairment of autonomic nervous system function in IPD without autonomic symptoms is frequent, and does not show clear association with clinical stage and the age of the patients.

Age Factors↗
PubMed2002

Exaggerated interictal cerebrovascular reactivity but normal blood flow velocities in migraine without aura.

Interictal cerebrovascular reactivity and blood flow velocities were tested in 23 patients with migraine without aura and 10 age- and sex-matched healthy controls by using the breath holding index (BHI). The mean systolic, diastolic and mean velocities and pulsatility indices were not different in the controls and patients. The BHI was found to be significantly greater (P=0011) in the patients (1.64 +/- 0.33) compared with the controls (1.26 +/- 0.37), showing an exaggerated reactivity to hypercapnia in migraineurs. Reactivity to pCO2 theoretically depends on pre-existing arteriolar tone and thereby on baseline velocity. Our finding of similar blood flow velocities in controls and patients suggests that the underlying cause for this high reactivity may not be an increased vasotonus but an increased sensitivity to changes in blood CO2 levels.

Adult↗
PubMed2001

Biochemical evidence of crossed cerebellar diaschisis in terms of nitric oxide indicators and lipid peroxidation products in rats during focal cerebral ischemia.

OBJECTIVES: Cerebral hypoperfusion in the contralateral cerebellar hemisphere after stroke is interpreted as a functional and metabolic depression, possibly caused by a loss of excitatory afferent inputs on the corticopontocerebellar pathway terminating in the cerebellar gray matter. This phenomenon is defined as crossed cerebellar diaschisis and can be diagnosed clinically by positron emission tomography, single-photon emission computed tomography, brain magnetic resonance imaging and electroencephalography in terms of regional cerebral blood flow or metabolic rate of oxygen measurements. MATERIALS AND METHODS: In the present study, nitric oxide indicators (nitrite and cyclic guanosine monophosphate) and lipid peroxidation products (malondialdehyde and conjugated dienes) were measured in rat cerebral cortices and cerebella after permanent right middle cerebral artery occlusion in order to assess the crossed cerebellar diaschisis. RESULTS: Nitrite values in ipsilateral cortex were significantly higher than those in contralateral cortex at 10 (P < 0.001) and 60 (P < 0.05) min of ischemia but no significant changes were observed in both cerebellum compared to the 0 min values. In both cerebral cortex and cerebellum cGMP levels at 10 and 60 min were significantly increased (P < 0.001). This increase was marked in ipsilateral cortex and contralateral cerebellum when compared with opposite cortex and cerebellum (P < 0.001). MDA values in ipsilateral cortex were significantly higher than those in contralateral cortex at 60 min of ischemia (P < 0.05). Contralateral cerebellar MDA values were found significantly higher than those in ipsilateral cerebellum at 0 (P<0.001) and 60 (P < 0.05) min of ischemia. In ipsilateral cortex, conjugated diene values at 0, 10, 60 min of ischemia were higher than those in contralateral cortex. On the other hand 0, 10, 60 min conjugated diene levels in contralateral cerebellum were significantly higher than those in ipsilateral cerebellum (P < 0.001). CONCLUSION: These findings support the interruption of the corticopontocerebellar tract as the mechanism of the crossed cerebellar diaschisis.

Afferent Pathways↗
PubMed2000

Trial of oral fumagillin for the treatment of intestinal microsporidiosis in patients with HIV infection. ANRS 054 Study Group. Agence Nationale de Recherche sur le SIDA.

OBJECTIVE: Intestinal microsporidiosis caused by Enterocytozoon bieneusi is a cause of chronic diarrhoea in patients with HIV infection for which there is no current therapy. This study was designed to assess the safety and efficacy of oral fumagillin in this infection. DESIGN: A dose-escalation trial. METHODS: Twenty-nine HIV-infected patients with E. bieneusi infection were consecutively enrolled in the trial. Oral doses of fumagillin were given to four groups of patients for 14 days: 10 mg/day (group 1), 20 mg/day (group 2), 40 mg/day (group 3), and 60 mg/day (group 4). Patients were seen at weeks 1, 2, 4 and 6 to assess safety and efficacy. Efficacy was assessed primarily by the clearance of microsporidia from stools and follow-up duodenal biopsies. RESULTS: Thirteen patients complained of abdominal cramps, vomiting or diarrhoea during the study, and three patients had fumagillin withdrawn because of adverse events. Thrombocytopenia, neutropenia and hyperlipasaemia were the most frequent biological adverse events. Twenty-one out of 29 patients transiently cleared microsporidia from their stools during the study. By week 6, however, all patients in groups 1, 2 and 3 had parasitic relapse. Interestingly, eight out of 11 (72%) patients treated with 60 mg/day (group 4) apparently cleared microsporidia from their gastrointestinal tract and gained weight. No parasitic relapse was documented in these eight patients during a mean follow-up of 11.5 months. CONCLUSION: Treatment with fumagillin at 60 mg/day for 14 days has promise as an effective oral treatment for E. bieneusi infections.

AIDS-Related Opportunistic Infections↗
PubMed1999

Effects of Plasmodium vivax malaria in pregnancy.

BACKGROUND: Plasmodium vivax is more common than P. falciparum as a cause of malaria in many parts of the tropics outside Africa. P. falciparum infection has harmful effects in pregnancy, but the effects of P. vivax have not been characterised. We investigated the effects of P. vivax infection during pregnancy. METHODS: Since 1986, pregnant Karen women living in camps for displaced people on the western border of Thailand have been encouraged to attend antenatal clinics. Karen women were screened for malaria and anaemia at each week of pregnancy until delivery, and pregnancy outcome recorded. We compared the effects of P. vivax infection on anaemia and pregnancy outcome with those of P. falciparum and no malaria infection in the first pregnancy recorded at the antenatal clinics. FINDINGS: There were 634 first episodes of pure P. vivax malaria in 9956 women. P. vivax malaria was more common in primigravidae than in multigravidae and was associated with mild anaemia and an increased risk of low birthweight (odds ratio 1.64 [95% CI 1.29-2.08], p<0.001). The birthweight was a mean of 107 g (95% CI 61-154) lower in women with P. vivax infection than in uninfected women. By contrast with P. falciparum malaria, the decrease in birthweight was greater in multigravidae. P. vivax malaria was not associated with miscarriage, stillbirth, or with a shortened duration of pregnancy. INTERPRETATION: P. vivax malaria during pregnancy is associated with maternal anaemia and low birthweight. The effects of P. vivax infection are less striking than those of P. falciparum infection, but antimalarial prophylaxis against P. vivax in pregnancy may be justified.

Adult↗
PubMed1997

Inhibitory role of N omega-nitro-L-arginine methyl ester (L-NAME), a potent nitric oxide synthase inhibitor, on brain malondialdehyde and conjugated diene levels during focal cerebral ischemia in rats.

The effect of N omega-nitro-L-arginine methyl ester (L-NAME) on ischemic neuronal damage was studied in a rat model of permanent focal cerebral ischemia in terms of ipsilateral and contralateral cortical and cerebellar tissue lipid peroxides. Forty-five male Swiss Albino rats were assigned to one of four groups; sham operated as control, subjected to right middle cerebral artery occlusion or injection of L-NAME (10 mg/kg i.p.) either 30 min before or just after right middle cerebral artery occlusion. Changes in lipid peroxides were expressed as nanomoles of malondialdehyde and conjugated diene per milligram of protein. Malondialdehyde values following 60 min of ischemia relative to contralateral cortex and conjugated diene levels in 0, 10 and 60 min of ischemia were found to be higher in ipsilateral cortex than in contralateral cortex. On the other hand, contralateral cerebellar malondialdehyde levels after 0 and 60 min of ischemia and conjugated diene levels after 0, 10 and 60 min of ischemia were higher than those in ipsilateral cerebellum. Pharmacological inhibition of nitric oxide synthase by L-NAME before or just after permanent middle cerebral artery occlusion significantly decreased the malondialdehyde and conjugated diene levels in both the cortex and the cerebellum. No significant differences were found in malondialdehyde values between rats that had been pre- and post-treated with L-NAME, but conjugated diene levels in the post-treated group seemed to be significantly lower than those in the pretreated group. On the whole, these results suggest that malondialdehyde and conjugated diene represent early biochemical markers of lipid peroxidation in ischemic tissues, reflecting the radical-mediated tissue damage.

Animals↗
PubMed1997

Effects of Lamotrigine on brain nitrite and cGMP levels during focal cerebral ischemia in rats.

Glutamate receptor antagonists are protective in animal models of focal cerebral ischemia. Lamotrigine (3,5-diamino-6-[2,3-dichlorophenyl]-1,2, 4-triazine) is an anticonvulsant drug that blocks voltage-gated sodium channels and inhibits the ischemia-induced release of glutamate. Experiments in primary neuronal cultures implicate nitric oxide (NO) as a mediator of glutamatergic neurotoxicity acting via N-Methyl-D-Aspartate (NMDA) receptors. The effect of glutamate release inhibitor, Lamotrigine upon NO and cGMP production has been examined in focal cerebral ischemia in rats. Focal cerebral ischemia was produced by the permanent occlusion of right middle cerebral artery (MCA) in urethane anesthetized rats. A number of indicators of brain NO production (nitrite, cGMP) were determined in ipsilateral and contralateral cerebral cortex and cerebellum after 0, 10, 60 min of focal cerebral ischemia. The same parameters were measured in rats treated with Lamotrigine (20 mg/kg, i.p.) 30 min before or just after the occlusion of the right MCA.

Animals↗
PubMed1997

The effects of nitric oxide synthase inhibitor, L-NAME on NO production during focal cerebral ischemia in rats: could L-NAME be the future treatment of sudden deafness?

Recent evidence in primary neuronal cell culture implicates NO as a mediator of glutamatergic neurotoxicity acting via N-methyl-D-aspartate (NMDA) receptors. In this study, we investigated the effects of inhibition of NOsynthase activity in focal cerebral ischemia in rats. Focal cerebral ischemia was produced by permanent occlusion of right MCA in urethane anesthetized rats. A number of indicators of brain NO production, nitrite and cGMP were determined in ipsilateral and contralateral cerebral cortex and cerebellum after 0, 10 and 60 minutes of focal cerebral ischemia. The same parameters were measured in rats pre- and posttreated with the potent Nitric oxide synthase (NOS) inhibitor, NW-nitro-L-arginine methyl ester (L-NAME).

Animals↗
PubMed1995

Painful unilateral epileptic seizure.

Two rare cases with focal, paroxysmal pain as the initial manifestation of partial epilepsy have been reported. The pain attacks subsided after treatment with anti-epileptic drugs.

Adolescent↗
PubMed1988

Visual evoked potentials in diabetes mellitus.

25 diabetic patients have been studied in order to investigate the possible effects of the disease on the central nervous system by means of pattern shift visual evoked potentials. Patients with diabetic retinopathy, glaucoma and cataract were excluded from the study. Results obtained from a control group of 30 normal subjects were compared to those of the patient group in which sural nerve conduction velocities have also been determined to see whether there is a correlation between peripheral and central involvement of the nervous system. In diabetic patients latency prolongation in the P100 and N140 components were observed. The N90-N140 interpeak latency was also prolonged. In addition, in patients with longstanding diabetes mellitus the incidence of VEP abnormalities was found to be high. Pathologic changes in VEP latencies did not show any correlation with sural nerve conduction abnormalities.

Adolescent↗
PubMed1986

[Immunoglobulin and complement levels in migraine].

There is circumstantial evidence to suggest that immune mechanisms are involved in the pathogenesis of migraine. Several workers have noted an increased incidence of allergy in patients with migraine and the disease has also been explained on an allergic basis. In this study the serum levels of IgG, IgA, IgM and C3 of 50 migraineurs are determined and the results were found to be increased realistically when compared by the control group. The results are compared by the literature.

Adolescent↗
PubMedDate not supplied

High Plasmodium falciparum resistance to chloroquine and sulfadoxine-pyrimethamine in Harper, Liberia: results in vivo and analysis of point mutations.

In Liberia, little information is available on the efficacy of antimalarials against Plasmodium falciparum malaria. We measured parasitological resistance to chloroquine and sulfadoxine-pyrimethamine (SP) in Harper, south-west Liberia in a 28-d study in vivo. A total of 50 patients completed follow-up in the chloroquine group, and 66 in the SP group. The chloroquine failure rate was 74.0% (95% confidence interval [95% CI] 59.7-85.4%) after 14 d of follow-up and 84.0% (95% CI 70.9-92.8%) after 28 d (no polymerase chain reaction [PCR] analysis was performed to detect reinfections in this group). In the SP group, the failure rate was 48.5% (95% CI 36.2-61.0%) after 14 d and 69.7% (95% CI 57.1-80.4%) after 28 d, readjusted to 51.5% (95% CI 38.9-64.0%) after taking into account reinfections detected by PCR. Genomic analysis of parasite isolates was also performed to look for point mutations associated with resistance. Genotyping of parasite isolates revealed that all carried chloroquine-resistant K-76T mutations at gene pfcrt, whereas the triple mutation (S108N, N511, C59R) at dhfr and the A437G mutation at dhps, both associated with resistance to SP, were present in 84% and 79% of pretreatment isolates respectively. These results seriously question the continued use of chloroquine and SP in Harper and highlight the urgency of making alternative antimalarial therapies available. Our study confirms that resistance to chloroquine may be high in Liberia and yields hitherto missing information on SP.

Animals↗
PubMedDate not supplied

Efficacy of amodiaquine for uncomplicated Plasmodium falciparum malaria in Harper, Liberia.

In the face of spreading chloroquine and sulfadoxine-pyrimethamine (SP) resistance, amodiaquine remains a cheap and efficacious alternative for treating uncomplicated Plasmodium falciparum malaria in many settings. In Harper, south-eastern Liberia, a previous study we conducted showed very high levels of resistance to both chloroquine and SP. In 2001, in an effort to look for possible alternatives, we measured in the same setting the efficacy of amodiaquine in a 28-d study in vivo, with results corrected by polymerase chain reaction genotyping to distinguish recrudescences from reinfections. In total, 107 children were included in the study and received a 3-d supervised course of 25 mg/kg amodiaquine. Of these, 81 were analysable at day 28. The overall failure rate was 19.8% (95% CI 11.7-30.1%) considering both parasitological and clinical outcomes. These results provide hitherto missing data on amodiaquine in Liberia, and confirm that the drug may still be efficacious in settings where chloroquine and SP are failing. We recommend the introduction of amodiaquine in association with artesunate as a first-line antimalarial in Harper.

Amodiaquine↗