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T Isbir

Publications and source records attributed to T Isbir.

33 records · Page 2Linked to original sources
PubMed1996

Bencyclane as an anti-sickling agent.

A vasodilating Ca2+ channel blocker, bencyclane, was used in 18 patients with homozygous sickle cell anaemia (SCD) to test the possible anti-sickling effect. With bencyclane intervention the Na(+)-K+ ATPase activity increased from 256 +/- 29 to 331 +/- 37 nmol Pi/mg protein/h (P < 0.0001) and the Ca(2+)-Mg2+ ATPase level increased from 172 +/- 12 to 222 +/- 44 nmol Pi/mg protein/h (P < 0.0001). The intracytoplasmic Ca2+ concentration reduced from 3.5 +/- 0.6 to 2.7 +/- 0.25 mumol/l (P < 0.0001). The patient's blood contained fewer irreversibly sickled cells (ISCs) (a reduction from 21.4% to 14.4%) (P < 0.05). At the same time MCHC of the erythrocytes decreased from 34.5 to 33.0 g/dl (P < 0.05). Bencyclane appears to be a promising anti-sickling agent that can be used orally in SCD.

Adolescent↗
PubMed1995

Effects of static magnetic field on specific adenosine-5'- triphosphatase activities and bioelectrical and biomechanical properties in the rat diaphragm muscle.

In this study, we aimed to clarify the effects of chronically applied static magnetic field (200 Gauss) on specific ATPase activities and bioelectrical and biomechanical responses in isolated rat diaphragm muscle. The mean activities of Na(+)-K+ ATPase and Ca2+ ATPase determined from the diaphragm homogenates were significantly higher in the magnetic field exposed group (n = 20), but that of Mg2+ ATPase was nonsignificantly lower compared to the control group (n = 13). Resting membrane potential, amplitude of muscle action potential, and overshoot values (mean +/- SE) in the control group were found to be -76.5 +/- 0.6, 100 +/- 0.8, and 23.5 +/- 0.6 mV, respectively; these values were determined to be -72.8 +/- 0.4, 90.3 +/- 0.5, and 17.2 +/- 0.4 mV in the magnetic field-exposed group, respectively. The latency was determined to increase in the experimental group, and all the above-mentioned bioelectrical differences between the groups were significant statistically. Force of muscle twitch was found to decrease significantly in the magnetic field-exposed group, and this finding was attributed to the augmenting effect of magnetic field on Ca2+ ATPase activity. These results suggest that magnetic field exposure changes specific ATPase activities and, thence, bioelectrical and biomechanical properties in the rat diaphragm muscle.

Adenosine Triphosphatases↗
PubMed1995

Correlation of alterations on Na(+)-K+/Mg+2 ATPase activity, lipid peroxidation and ultrastructural findings following experimental spinal cord injury with and without intravenous methylprednisolone treatment.

The sodium-potassium activated and magnesium dependent adenosine-5'-triphosphatase (Na(+)-K+/Mg+2 ATPase EC 3.6.1.3.) activity and lipid peroxidation and early ultrastructural findings are determined in rat spinal cord at the early stage of trauma produced by a surgical clip on the thoracal 2-7 segments. The effect of treatment with intravenous methylprednisolone (MP) was evaluated the basis of these biochemical alterations and ultrastructural findings in the same model. The specific activity of the membrane bound enzyme Na(+)-K+/Mg+2 ATPase was promptly reduced in as early as ten minutes following spinal cord injury and remained at a level lower than the levels in the control group and in the sham-operated group. Methylprednisolone treatment immediately after the trauma attenuated the inactivation of Na(+)-K+/Mg+2 ATPase. On the other hand, there was significant difference in lipid peroxide content between the sham-operated and the injured animals. Methylprednisolone treatment reduced thiobarbituric acid reactive substance (TBARS) content in Group IV. We determined a positive relationship among membrane-bound enzyme Na+K+/Mg+2 ATPase activity, malondialdehyde (MDA) content and early ultrastructural changes in the traumatized and treated groups.

Animals↗
PubMed1995

The effect of the treatment of high-dose methylprednisolone on Na(+)-K(+)/Mg(+2) ATPase activity and lipid peroxidation and ultrastructural findings following cerebral contusion in rat.

BACKGROUND: Although use of corticosteroid in the management of head trauma has caused a great deal of controversy, corticosteroids have long been an adjunct in the management of severe closed head injury. The glucocorticoid steroid methylprednisolone (MP) has been proven to have significant antioxidant effect when administered in an antioxidant-high dose after central nervous system injury. METHODS: The sodium-potassium activated and magnesium dependent adenosine-5'-triphosphatase (Na(+)-K(+)/Mg(+2) ATPase EC.3.6.1.3.) activity, lipid peroxidation, and early ultrastructural findings were determined during the immediate posttraumatic period in rats. Mechanical brain injury was produced when a calibrated weight-drop device is allowed to fall on the skull's convexity over the right hemisphere, 1 to 2 mm lateral from the midline. In group I, rats were used to determine Na(+)-K(+)/Mg(+2) ATPase activity, the extent of lipid peroxidation, by measuring the level of malondialdehyde content and normal ultrastructural findings in two different brain areas (cerebral cortex and brain stem). In group II, physiologic saline was administered right after trauma in the same amount as methylprednisolone. In group III rats, methylprednisolone (30 mg/kg) was administered intravenously right after trauma. RESULTS: Na(+)-K(+)/Mg(+2) ATPase activity significantly decreased in the cerebral cortex and in brain stem within 2 hours after trauma (p < 0.05). There was significant difference in malondialdehyde content between groups II and III (p < 0.05). Methylprednisolone treatment reduced malondialdehyde content and induced the recovery of Na(+)-K(+)/Mg(+2) activity. CONCLUSIONS: These data suggest that inactivation of Na(+)-K(+)/Mg(+2) ATPase is closely correlated to changes of lipid peroxidation and the alteration of the ultrastructural findings in the early phases after head trauma. The glucocorticoid steroid methylprednisolone has been proven to have significant effect in activation of Na(+)-K(+)/Mg(+2) ATPase with significant reduction of malondialdehyde content.

Animals↗
PubMed1995

Effects of naloxone on sodium- and potassium-activated and magnesium-dependent adenosine-5'-triphosphatase activity and lipid peroxidation and early ultrastructural findings after experimental spinal cord injury.

Endorphins have been implicated in the pathophysiology of spinal cord injury. The effect of naloxone on the sodium- and potassium-activated and magnesium-dependent adenosine-5'-triphosphatase (Na(+)-K+/Mg+2 ATPase, EC.3.6.1.3.) activity, lipid peroxidation, and early ultrastructural findings were studied in rats at the early stage of spinal cord injury, produced with an aneurysm clip on the T2-T7 segments. The rats were divided into four groups. The 10 rats in Group I, which had no injury and received no medication, were used for determining Na(+)-K+/Mg+2 ATPase activity, the extent of lipid peroxidation (by measuring the level of thiobarbituric acid-reactive substances as malondialdehyde), and normal ultrastructural findings. On the 15 rats in Group II, without spinal cord injury, only laminectomy was performed to determine the effect of surgery on the biochemical indices and findings. In the 15 rats in Group III, physiological saline was administered intraperitoneally in an amount equivalent to that of the naloxone administered immediately after spinal cord injury. In the 15 rats in Group IV, 0.5 mg of naloxone was administered intraperitoneally as a single dose immediately after injury and again 60 minutes after injury. The Na(+)-K+/Mg+2 ATPase activity was promptly reduced after spinal cord injury and remained in a lower level than the levels of Groups I and II during 120 minutes after injury. Naloxone treatment, immediately after trauma, attenuated the inactivation of Na(+)-K+/Mg+2 ATPase. On the other hand, there was a significant difference in the malondialdehyde content between animals in Groups I and III. Naloxone treatment reduced the malondialdehyde content in Group IV.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Zinc, copper and magnesium status in insulin-dependent diabetes.

In 20 patients with insulin-dependent diabetes mellitus the concentration of zinc in serum was 56.53 +/- 2.36 micrograms/dl (mean +/- SD). This was significantly lower (p < 0.01) than the levels measured in matched controls. In the same patients the concentrations of serum copper and magnesium were 123.46 +/- 6.59 micrograms/dl and 17.38 +/- 0.52 mg/l respectively. These copper values were higher and the magnesium levels were lower than in the control subjects (p < 0.01). These changes may be associated with the development of insulin resistance and it is proposed that patients will improve if trace elements are given as part of the therapy.

Adolescent↗
PubMed1980

Albumin Naskapi variant in North American Indians and Eti Turks.

Both conventional polyacrylamide gel electrophoresis and a new type of electrophoretic screening procedure indicate that the polymorphic albumin variants Naskapi, found chiefly in the Naskapi Indians of Quebec, and Mersin, found in the Eti Turks of southeastern Turkey, are molecularly identical or very similar and that the amino acid substitution site in these variants is located between residues 330 and 446. This discovery is consistent with a genetic relationship between the Eti Turks and American Indians. We also report a new variant found in the Eti Turks, albumin Adana, which migrates similarly to albumin B on conventional gels but which our new system shows to differ from the common albumin A and albumin B by a substitution between residues 549 and 585.

Arizona↗
PubMed1980

The role of cation-activated ATPases in transmitter release from the rat iris.

Release of noradrenaline (NA) from isolated rat iris during perfusion in K+-free medium was confirmed. Direct biochemical measurement of different cation-activated ATPases did not reveal any definite relationship between Na+K+ ATPase and NA release. A significant increase in Ca++Mg++ ATPase activity was found on termination of NA release obtained by reintroduction of K+ to the medium. Criticism of the model for studying enzymatic control of transmitter release under physiological conditions is presented. It is suggested that removal of intracellular Ca++ ions by a calcium pump is directly associated with termination of transmitter release.

Adenosine Triphosphatases↗
PubMedDate not supplied

Apolipoprotein-E gene polymorphism and lipid profiles in Alzheimer's disease.

In this study, the relationship between lipid profiles of sera and apolipoprotein E (apo E) gene polymorphism was investigated in 35 patients with Alzheimer's disease (AD) and 29 healthy people. Apo E genotypes and allele frequencies of the AD patient group were: apo E2/3, 2 (5.7 percent); apo E2/4, 1 (2.9 percent); apo E3/3, 26 (74.3 percent); apo E3/4, 5 (14.3 percent); apo E4/4, 1 (2.9 percent); epsilon 2, 3(4.2 percent); epsilon 3, 59 (84.2 percent); epsilon 4, 8 (11.4 percent). The healthy group's apo E genotypes and allele frequencies were: apo E2/3, 1 (3.4 percent); apo E3/3, 27 (93.1 percent); apo E3/4, 1 (3.4 percent); epsilon 2, 1 (1.7 percent); epsilon 3, 56 (96.5 percent); epsilon 4, 1 (1.7 percent). In Alzheimer's cases, epsilon 4 allele frequencies increased significantly as compared to the healthy group (p < 0.05). When the effects of the apo E isoforms on lipid profiles were evaluated, a relationship between apo E epsilon 4 allele and high total levels of serum cholesterol was found, whereas of apo E epsilon 2 allele was associated with the low total cholesterol of serum, although the difference was not statistically significant (p > 0.05). This study confirms the association of apo E epsilon 4 allele with lipid profiles in AD patients.

Aged↗
PubMedDate not supplied

Interaction between apolipoprotein-E and angiotensin-converting enzyme genotype in Alzheimer's disease.

Both apolipoprotein-E (apo-E) epsilon 4 allele and angiotensin-converting enzyme (ACE) deletion (D) polymorphism have been associated with a high risk for coronary heart disease. Increased frequency of the epsilon 4 allele has also been reported in patients with late-onset of familial and sporadic Alzheimer's disease (AD). The primary aim of this study is to examine the possible relationship between the ACE gene polymorphism and AD. The second aim of this study is to explore the relation of the ACE and apo-E genotypes with AD. Polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), and agarose gel electrophoresis techniques were used to determine the apo-E and ACE genotypes. The frequencies of ACE D and ACE insertion (I) allele among AD patients and controls were 55.7 percent versus 44.2 percent and 51.7 versus 48.2 percent, respectively. Apo-E allele frequencies in the AD group for epsilon 2, epsilon 3 and epsilon 4 were, 1.7 percent, 96.5 percent, and 1.7 percent, respectively. The apo-E allele frequencies of healthy groups for epsilon 2, epsilon 3 and epsilon 4 were 1 percent, 56 percent, and 1.7 percent, respectively. In conclusion ACE D and apo epsilon 4 allele were found to be more frequent in patients with Alzheimer's disease than in the control group.

Aged↗
PubMedDate not supplied

The effects of Brassica oleraceae var capitata on epidermal glutathione and lipid peroxides in DMBA-initiated-TPA-promoted mice.

BACKGROUND: The objective of the present study was to determine if modulation of GSH-dependent antioxidant protective system by Brassica oleraceae var capitata might inhibit the molecular mechanism of skin tumor promotion. MATERIALS AND METHODS: In a two stages skin carcinogenesis model, the protocol used included a single topical application of 200 nmol of the initiator 7,12-dimethyl-benz(a) anthracene (DMBA) to the backs of mice, followed 1 week later by promotion with 10 nmol of 12-O-tetradecanoyl-phorbol-13 acetate (TPA) twice weekly for 30 weeks. In addition to this regimen, 0.1 g/L brassica extract was added water week prior to the initiating dose of DMBA in the treatment group. Tissue glutathione (GSH) contents and levels of lipid peroxidation products (measured as thiobarbituric-acid (TBA)-reactive substances) were quantitated in the skin tumors generated by the initiation-promotion protocol. RESULTS: It was observed that the tumor incidence and tumor multiplicity in the treatment group was highly significantly low compared to the first group of mice (p < 0.001 and p < 0.001, respectively). In the treatment group, GSH content in the papillomas was higher than in the non-involved skin surrounding the papillomas. CONCLUSIONS: We suggest that the anticarcinogenicity of Brassica may be linked to its ability to facilitate or enhance the activity of the natural GSH-dependent antioxidant protective system of the epidermal cells during the later stages of skin tumor promotion.

9,10-Dimethyl-1,2-benzanthracene↗
PubMedDate not supplied

Kinetic properties of potassium stimulated ATPase purified from gastric mucosa.

In this study, partially purified K+-H+ ATPase from frog gastric mucosa were obtained by using differential and density gradient centrifugation. Optimum activity of K+-H+ ATPase (Vmax), Michealis-Menten constant (Km) and Hill coefficient (h) were found as 83.3 mumol Pi.mg prot-1.h-1, 95.2 microM and 0.91, respectively. Enzyme preparations were more stable in glycerol solutions stored at -40 degrees C. Minimum activity lost was determined for samples stored in 40% (v/v) glycerol solution at -40 degrees C for two months.

Adenosine Triphosphatases↗