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Biomedical subjects

I Koncz

Publications and source records attributed to I Koncz.

15 recordsLinked to original sources
PubMed2001

The nootropic drug vinpocetine inhibits veratridine-induced [Ca2+]i increase in rat hippocampal CA1 pyramidal cells.

The alkaloid derivative vinpocetine (14-ethoxycarbonyl-(3alpha,16alpha-ethyl)-14,15-eburnamine; Cavinton) has a well known beneficial effect on brain function in hypoxic and ischemic conditions. While it increases CNS blood flow and improves cellular metabolism, relatively little is known about vinpocetine's underlying molecular mechanisms on the single cell level. Since apoptotic and necrotic cell damage is always preceded by an increase in [Ca2+]i, this study investigated the effect of vinpocetine on [Ca2+]i increases in acute brain slices. Sodium influx is an early event in the biochemical cascade that takes place during ischemia. The alkaloid veratridine can activate this Na+ influx, causing depolarization and increasing [Ca2+]i in the cells. Therefore, it can be used to simulate an ischemic attack in brain cells. Using a cooled CCD camera-based ratio imaging system and cell loading with fura 2/AM, the effect of vinpocetine on [Ca2+]i changes in single pyramidal neurons in the vulnerable CA1 region of rat hippocampal slices was investigated. Preperfusion and continuous administration of vinpocetine (10 microM) significantly inhibited the elevation in [Ca2+]i induced by veratridine (10 microM). When the drug was administered after veratridine, it could accelerate the recovery of cellular calcium levels. Piracetam, another nootropic used in clinical practice, could attenuate the elevation of [Ca2+]i only at a high, 1 mM, concentration. We have concluded that vinpocetine, at a pharmacologically relevant concentration, can decrease pathologically high [Ca2+]i levels in individual rat hippocampal CA1 pyramidal neurons; this effect might contribute to the neuroprotective property of the drug.

Animals↗
PubMed2000

Role of sodium channel inhibition in neuroprotection: effect of vinpocetine.

Vinpocetine (ethyl apovincaminate) discovered during the late 1960s has successfully been used in the treatment of central nervous system disorders of cerebrovascular origin for decades. The increase in the regional cerebral blood flow in response to vinpocetine administration is well established and strengthened by new diagnostical techniques (transcranial Doppler, near infrared spectroscopy, positron emission tomography). The latest in vitro studies have revealed the effect of the compound on Ca(2+)/calmodulin dependent cyclic guanosine monophosphate-phosphodiesterase 1, voltage-operated Ca(2+) channels, glutamate receptors and voltage dependent Na(+)-channels; the latest being especially relevant to the neuroprotective action of vinpocetine. The good brain penetration profile and heterogenous brain distribution pattern (mainly in the thalamus, basal ganglia and visual cortex) of labelled vinpocetin were demonstrated by positron emission tomography in primates and man. Multicentric, randomized, placebo-controlled clinical studies proved the efficacy of orally administered vinpocetin in patients with organic psychosyndrome. Recently positron emission tomography studies have proved that vinpocetine is able to redistribute regional cerebral blood flow and enhance glucose supply of brain tissue in ischemic post-stroke patients.

Animals↗
PubMed1991

[Congestive gastropathy].

15 patients with congestive gastropathy were reported including clinical and pathological characteristics of the disease. Every patient had alcoholic liver cirrhosis and portal hypertension. 6 patient's stomach was resected while in 2 further cases the disease was found at autopsy. In additional 7 cases the characteristic microvascular changes were observed in endoscopic biopsy specimens from the gastric mucosa. The authors presume that this disease has an acute and a chronic stage. In the acute stage dilated capillaries are present under the surface, not related to the inflammation of gastric mucosa. This phenomenon was described in the literature. In the chronic stage there are dilated and tortuous vessels in the submucosal layer surrounded by collagenous connective tissue. The authors suppose that the thick and fibrotic submucosal layer causes microcirculatory disturbances in the gastric mucosa. The impaired microcirculation may cause extensive ulcers with profuse and sometimes lethal bleeding.

Adult↗
PubMed1989

[Ischemic gastritis--a clinico-pathological entity?].

Eight ulcerative gastroduodenitis are reported in connection with the chronic circulatory disorders. In four patients the severe sclerotic narrowing of splanchnic arteries was proved by autopsies following the operation. Characteristics of chronic ischemic disease of the stomach were as follows: lack of symptoms of chronic peptic ulcus in the previous history; old age; severe pain; sudden losing weight and the ineffectiveness of usual therapy. X-ray, endoscopy as well as intraoperative findings raised the suspicion of a malignant tumour. Authors are of the opinion that chronic ischemic disease of the stomach is an entity pathologically as well as clinically. Histology of the reported cases were compared with 20 chronic peptic ulcers of the stomach and differences were described. Some giant ulcers in old age are suggested belonging to this group of diseases. Practical importance of better knowledge of the ischemic gastritis was emphasized. After recanalisation of the vessels spontaneous healing of gastric ulcers has been reported. Importance of selective arteriography was stressed in cases of gastric ulcers of unusual shape and considerable size.

Aged↗
PubMed1989

Examination of Cavinton effect in elderly diabetic patients.

The effect of Cavinton tablet has been examined in elderly diabetic patients. According to the observations the intellectual performance of the treated patients improved significantly, and their neurological symptoms were moderated as well. The drug did not influence carbohydrate or lipid metabolisms nor did it affect the systemic blood pressure. The results obtained prove that the drug may successfully be used for the treatment of nervous symptoms of elderly diabetic patients. The assure an effective therapy the drug administration has to be started as early as possible--before the development of nervous symptoms. The dosage of the product has to be adjusted individually. Obviously, the currently accepted other drug therapies of manifesting nervous symptoms have to be used as well and the other diseases accompanying advanced age need also be treated.

Aged↗