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Biomedical subjects

Y Ates

Publications and source records attributed to Y Ates.

17 recordsLinked to original sources
PubMed2005

Effects of pregnancy and lactation on bone mineral density, and their relation to the serum calcium, phosphorus, calcitonin and parathyroid hormone levels in rats.

The aim of this study was to evaluate the net changes in bone mineral density (BMD) during the reproductive cycle, and their relation with changes in serum calcium (Ca), phosphorus (P), PTH and calcitonin levels in rats. Twenty-seven female Wistar rats were included in this study. They were divided into three groups as pregnant, lactating and control groups. BMDs of lumbar vertebrates, femoral and tibial bones, and Ca, P, calcitonin and PTH levels were measured at the end of pregnancy, at the end of lactation and in nulliparous controls. In the pregnant group, the BMDs of rats were significantly higher in lumbar vertebrates, femoral and tibia bones than those of the control group (p<0.05). Their PTH and Ca levels were significantly lower than the control group (p<0.05). However, no statistically significant difference was found regarding P and calcitonin levels when compared to those of the control group. In the lactating group, the BMDs were significantly lower in lumbar vertebrates, femoral and tibia bones than those seen in the control and pregnant groups (p<0.05). Ca and PTH levels were significantly higher in lactating rats than in those of pregnant rats (p<0.005). Normal pregnancy increases BMD in rats, whereas lactation decreases it. Change in PTH levels is supposed to contribute to the mineralization and demineralization of the skeleton during pregnancy and lactation, respectively.

Animals↗
PubMed2001

Rifampicin test in the diagnosis of Gilbert's syndrome.

Gilbert's syndrome (GS) is characterised by the existence of chronic mild unconjugated hyperbilirubinaemia. The value of rifampicin as a provocative test for the diagnosis of GS was evaluated and compared with a fasting test. Twenty-two patients with GS, 15 patients with chronic liver disease and 20 healthy controls were included. Both rifampicin and fasting tests were applied to all subjects. In the fasting test, the subjects were given a 400 calorie/day diet for 24 hours; in the rifampicin test, unconjugated bilirubin levels was measured before and four hours after taking 600 mg of rifampicin. Both tests achieved a significant increase in mean unconjugated bilirubin levels in patients with GS but not in the controls. The sensitivity and specificity of a rifampicin test in the diagnosis of GS were comparable with the fasting test. However, both tests caused a significant increase in unconjugated bilirubin levels in nearly half the patients with chronic liver disease. A rifampicin test may be used in the diagnosis of suspected GS instead of a fasting test, as it is simpler and more practical. However, its specificity for GS is not sufficient, because it also causes an increase in unconjugated bilirubin levels in some patients with chronic liver disease.

Enzyme Inhibitors↗
PubMed1999

Efficacy of omeprazole plus two antimicrobials for the eradication of Helicobacter pylori in a Turkish population.

Omeprazole combined with 2 antimicrobials has been suggested as a first-line option for Helicobacter pylori eradication in recent years. However, controversy exists regarding the efficacy of this protocol. This open-label, prospective clinical study investigated the efficacy of omeprazole-based triple therapy for H pylori eradication in 518 patients with H pylori-positive functional dyspepsia with or without duodenal ulcer. Amoxicillin, macrolides (clarithromycin or roxithromycin), and nitroimidazoles (metronidazole, ornidazole, or tinidazole) were the antibiotics used in the study. Nonulcer patients were randomly assigned to 1 of 8 different treatment protocols and duodenal ulcer patients were randomly assigned to 1 of 4 different treatment protocols consisting of omeprazole (20 mg once daily for nonulcer patients, 20 mg twice daily for ulcer patients for 14 days) with a combination of 2 of the above antimicrobials (for 10 days). H pylori infection was assessed by histologic findings and a rapid urease test before therapy and 4 weeks after therapy ended. Four hundred fifty-nine patients completed their regimens; 327 had functional dyspepsia (180 men, 147 women; median age, 39 years; range, 18 to 70 years) and 132 had ulcers (81 men, 51 women; median age, 40 years; range, 18 to 70 years). Eradication of H pylori was achieved in 58.8% (270 of 459) of all patients, 58.1% (190 of 327) of nonulcer dyspeptic patients, and 60.6% (80 of 132) of duodenal ulcer patients. The eradication rate varied from 47.2% to 69.4% in different treatment protocols. There were no statistically significant differences in eradication rates in any treatment group. All drugs were generally well tolerated in all groups, and no patient discontinued treatment because of side effects. Therapy with omeprazole and 2 antimicrobials for H pylori had limited efficacy in a Turkish population. The reason for these results, which conflict with those of other studies, is not clear. Further investigations of regimens for the eradication of H pylori in our population are necessary.

Adolescent↗
PubMed1998

Effect of 25-OH-vitamin D on fracture healing in elderly rats.

To investigate the effect of 25-OH-vitamin D supplements (calcidiol) on fracture healing in the elderly, an experimental model with 15 18-month-old female Wistar rats was designed. An experimental fracture in the middle third of both femora of each rat was made. Then the rats were randomly assigned to two groups: one group was subcutaneously treated with 25-OH-vitamin D during all healing processes, and the other group (the control group) was not. After 5 weeks of healing, the animals were killed and both femora were extracted. Blood samples were collected before fracture and at death to determine the levels of 25-OH-vitamin D. All bones that were extracted were subjected to a torsion test to assess healing; a significantly greater maximum shear force before failure was supported in the treated group (p < 0.01). Moreover, a positive correlation (p < 0.01; r=0.55) was found between blood levels of 25-OH-vitamin D at death and the mechanical strength of the callus. Thus, the administration of 25-OH-vitamin D after the experimental fracture significantly improved the mechanical strength of the fractured bone. If similar results are found in the human, then treatment with 25-OH-vitamin D after the occurrence of a fracture would be a good way to improve fracture healing in the elderly.

Aging↗
PubMed1992

The relationship between the treatment of congenital dislocation of the hip and avascular necrosis.

The most important complication following the treatment of congenital dislocation of the hip is avascular necrosis. The potential sequelae that may arise after the onset of avascular necrosis are worse than if the hip remained dislocated. We evaluated 38 hips in which avascular necrosis developed after reduction. The average patient age at the time of reduction was 4.3 years, with a follow up of 6 to 15 years. Twelve hips had closed reduction and 26 had open reduction. Following reduction, 8 hips had Type I, 6 had Type II, 9 had Type III, and 15 had Type IV avascular necrosis. In this article, we evaluate our cases and review current literature on the subject. Close follow up and timely interventions can reduce potential sequelae to a minimum.

Adolescent↗
PubMed1980

Action of short-term cycloheximide administration associated with colchicine on nuclear and chromosome structure in cleaving Newt eggs. Reappearance of chromomeres?

Association of short-term cycloheximide (CHM) administration (1/3, 1/2 or 1 cycle) with long-term treatment by colchicine (Co) confirms the results obtained by CHM alone under similar conditions, namely the striking relationship between the starting-time of treatment and the type of nuclei obtained (centred telophasic or non-centred prophasic). This relationship is highly significant. Various nuclear structures were observed: they correspond to a special evolution of the abnormal nuclei during telophase, telo-prophase and prophase which is very different from that in untreated ones. A difference in evolution of the central and peripheral parts of the same nucleus explains their centred structure. On the contrary, this difference disappears at prophase. The association CHM-Co favours the unveiling of beads which are interpreted as prophasic chromomeres. These beads are of different size, spacing and form according to the moment of the prophasic evolution attained. Electron microscopy study confirms the strong dispersion of chromatin by CHM and the beaded appearance of chromosomes by CHM and Co. Simultaneously, many dense bodies are accumulated in the centrospheres, as after quinoline and glutaraldehyde administration. The mechanisms of production of centred nuclei and of the beaded appearance of chromosomes are discussed.

Animals↗
PubMed1978

Cytological characteristics and classification of spindle inhibitors according to their effects on segmentation mitoses.

The effects of spindle inhibitors and of protein synthesis inhibitors on segmentation mitoses allow us to classify them into six groups : 1. Colchicine type : destruction of the whole achromatic apparatus and centrospheres without storing of dense bodies; 2. Quinoline type : same effect on the achromatic apparatus, but blocked centrospheres with accumulation of dense bodies; 3. Chloralhydrate type : Incomplete destruction of achromatic apparatus, spindle residue which maintains the chromosomes in a star shape, inactive centrospheres sequestered by the reticulum, but without accumulation of dense bodies; 4. Phenylurethane type : Incomplete and reversible action, which leads to easy production of pluripolar mitoses; 5. Carboxylic acid type : dissociation of the spindle, sometimes with blocking of the centrosphere, together with profound chromosome changes without primitive breaks; the intensity and quality of their action is related to the number of carbon atoms in the acid considered; 6. Protein synthesis inhibitor type : (cycloheximide, pederin) characterized by a stop of the nuclear cycle at telo-prophase when the action is sufficient, chromosome abnormalities, sometimes, reduced to strings of beads, and freeing of asters; at weaker concentrations mitosis is possible, but the congression of chromosomes at the equator is abnormal because of functional disturbance of the kinetochores. The nature and grading of these effects, their association (or non - association) to chromosome damage, the soundness of the spindle when only the chromosomes are affected (nitrogen mustard) make this one of the tests which gives the most specific data about the action of antimitotic substances.

Amides↗
PubMed1976

Ultrastructure of segmentation mitoses in cleaving newt eggs after blocking of centrospheres by quinoline.

In quinoline treated blastomeres of Triturus helveticus Raz. and Pleurodeles waltlii Michah., microtubules disappear and around the centrioles markedly enlarged dense bodies accompanied by striated bodies are accumulated, from prophase beyond metaphase. It is concluded that these bodies in untreated cells play a role in the formation of the spindle microtubules. - During metaphase the chromosome are smooth-surfaced and show a pronounced tendency to stickiness. During ana-telophase they become surrounded by nuclear membranes and form caryomeres. - Qinoline does not interfere with centriole replication, but prevents the separation if diplosomes that have been already formed, if it acts before that separation. - Some centrioles exhibit different degrees of ultrastructural disarrangement.

Animals↗
PubMed1976

[The effect of formamide on the achromatic apparatus and the chromosomes of dividing pleurodele eggs: an electron microscope study].

Electron microscope studies of blastulae of Pleurodeles waltlii Michah., treated with formamide (0,5 M for 17 hours), show various abnormalities concerning centrospheres, chromosomes and microtubules as well. At the prophase stage, the centrospheres may display at their outer region an accumulation of dense bodies, which shows a temporary blocking of these centrospheres. At metaphase the poles of pluripolar mitoses appear more or less separated from the material which contains the chromosomes of the equatorial region. Each of these poles contains an unique centriole and therefore it is considered as resulting of the subdivision of a normal anaphasic pole. Astral and spindle microtubules are very reduced in number and more or less shortened. The chromosomes are without any recognizable kinetochcre, they show various degrees of condensation. All these electron microscope observations confirm the light microscope ones, and we may conclude that formamide has a double action on microtubules formation and on the ultrastructure of chromosomes, the latter perhaps by a direct action on DNA protein complexes.

Animals↗
PubMed1975

[Mechanism of the blocking of the centrosphere by substances similar to quinoline. Its prevention with spindle inhibitors similar to colchicine].

A colchicine-like substance, vincaleukoblastine (2.10-4M, 3 to 6 hours), prevents the blocking of the centrosphere which would be produced by quinoline or by a similar substance (glutaraldehyde), to the extent of the inhibition of polarity by this colchicine-like substance. This is interpreted as due to the fact that each molecule of colchicine-like substance binds to a single subunit (or heterodimer) of tubulin and consequently prevents the constitution of storage structures. It is supposed that on the contrary quinoline-like substances bind to several subunits of tubulin and that they can stabilize the storage structures, binding to them in several points. The ultrastructural study demonstrates that when the centrosphere is blocked by quinoline, there is accumulation, hypertrophy and permanence of the "dense bodies" later than prophase; sometimes they are fused in a large "dense mass". The "dense bodies", and perhaps the "striated bodies", may therefore be interpreted as constituting morphologically the storage structures, which enlarge when all the astral and spindle microtubules completely disappear by action of a quinoline-like substance.

Aldehydes↗