Search PubMed⌕ Search

Biomedical subjects

B Yilmaz

Publications and source records attributed to B Yilmaz.

At least 37 records · Page 2Linked to original sources
PubMed1999

A retrospective comparison of allogeneic peripheral blood stem cell and bone marrow transplantation results from a single center: a focus on the incidence of graft-vs.-host disease and relapse.

To detect the effect of the stem cell source, allogeneic peripheral blood stem cell transplantations (alloPBSCTs) performed between 1995 and 1997 from human leukocyte antigen (HLA)-identical siblings in 40 patients with acute and chronic hematological disorders were compared with a historical group of 40 patients with similar variables who had received allogeneic bone marrow transplants (alloBMTs) between 1993 and 1995. Patients in both groups were identical except that both the recipient and the donor ages were, on average, higher in the alloPBSCT group (26 vs. 36 [p = 0.005] and 27 vs. 32 [p = 0.024], respectively). Patients received similar therapy excluding posttransplant granulocyte colony-stimulating factor administration (97% in alloBMT vs. 12.5% in alloPBSCT). The median time to reach neutrophil counts >0.5 x 10(9)/L and platelet counts >20 x 10(9)/L was 13 and 14 days, respectively, in patients receiving alloPBSCTs compared with 19 and 27 days in patients receiving alloBMTs (p = 0.0014 and p = 0.0002). The alloPBSCT group required similar transfusions of red blood cells or platelets. The incidence of grade II-IV acute graft-vs.-host disease (aGVHD) was similar in both groups. However, chronic GVHD (cGVHD) of all grades developed in 78.1% of patients in the alloPBSCT group after a median follow-up period of 12.5 (range 0.5-34) months. In alloBMT recipients, cGVHD of all grades developed in 21.4% after a median follow-up period of 38 (range 0.5-62) months (p = 0.00001). Day 100 transplant-related mortality was also similar: 20% (8 of 40) in the alloBMT patients and 17.5% (7 of 40) in the alloPBSCT group. Although not statistically significant, a relatively higher relapse rate occurred in the alloBMT group (21.4 vs. 10.7%). The estimated disease-free survival in month 24 was 51.3% for alloBMT and 54.6% for alloPBSCT, and the estimated overall survival in month 24 was 56.1% for alloBMT and 64.6% for alloPBSCT. In conclusion, this retrospective comparison suggests that alloPBSCT from HLA-identical donors is associated with faster engraftment, fewer transfusions, and no greater incidence of aGVHD, but a high incidence of cGVHD.

Adolescent↗
PubMed1999

Effect of antibiotics and anti-inflammatory agents on the purified protein derivative response in the rat.

We investigated the effects of several antibiotics and anti-inflammatory agents on the purified protein derivative (PPD) response in the rat. Animals were immunized with Mycobacterium bovis vaccine BCG. Antibiotics and anti-inflammatory drugs were administered at therapeutic doses for 10 d. Chloramphenicol, erythromycin, aspirin and ibuprofen suppressed the PPD response, but penicillin and acetaminophen had no significant effects.

Animals↗
PubMed1999

The comparison of intraocular pressure reductions after isometric and isokinetic exercises in normal individuals.

The lowering effect of physical exercise on intraocular pressure (IOP) has been reported both in healthy people and those with glaucoma, but a comparison of the lowering effect of isometric and isokinetic exercises on IOP has not been conducted in any study. Our aims were to investigate the relationship between intensity of exercise and IOP, and whether a significant difference in IOP lowering effect existed between isometric and isokinetic exercises. Sixty-seven patients with an age range of 23-40 who had no ocular disease were randomly divided into two groups. While 31 patients in the first group, group A, performed isokinetic exercise with the Cybex 6000 dynamometer, 32 patients in the second group, group B, had isometric exercises with the same machine. IOP was measured in the right eye of patients with Shiotz tonometer just before and 10 min following exercise. Exercise intensity and total energy consumption were determined by the machine for each patient. While IOP values measured before exercise, the degree of exercise applied, and total energy consumption did not differ significantly between groups, both isometric and isotonic exercises lowered IOP significantly. As a result, isometric and isokinetic exercises lowered IOP in ophthalmologically normal subjects with direct relationship to exercise intensity and total energy consumption. Since the pressure lowering effect of isokinetic exercise was more significant, it might prove useful to glaucomatous patients.

Adult↗
PubMed1998

Effects of hematoma on the short-term fate of experimental microvenous autografts.

The early effects of hematoma on the healing pattern of interpositional vein grafts were studied in 60 rats. In all animals, vein grafts approximately 10-mm in length were used to bridge defects created in the femoral artery and vein on the same side, with a 1:1 graft-to-host diameter match. Grafted vessels were completely covered with hematoma and separated from the surrounding tissue in 30 animals, while the other 30 rats served as controls. Both groups were divided into six subgroups of five animals each, according to the age of the grafts: 1, 3, 5, 7, 14, and 21 days. Graft patency and healing were assessed both clinically and histologically 20/30 (66.6 percent) of the interarterial and 27/30 (90 percent) of the intervenous vein grafts in Group 1 (hematoma group), and 28/30 (93.3 percent) of the interarterial and 29/30 196.6 percent) of the intervenous vein grafts in Group 2 (controls) were found patent. The patency rate of the interarterial vein grafts in the hematoma group was statistically significantly lower than in the control group and than in the intervenous vein grafts of the same group (p<0.005). The majority of interarterial vein-graft failures occurred after postoperative day 7 in Group 1. Patent specimens were examined under scanning electron and light microscopy. The authors concluded that perivascular hematoma caused spasm and flow disturbance, prolonged vessel-wall ischemia, and severe vessel-wall injury in the arterial circulation of the microvenous grafts. It also delayed the healing process and subjected the grafts to the development of occlusive mural thrombus. In contrast, the healing pattern of the intervenous vein grafts was not markedly influenced by perivascular hematoma, and equilibrium between thrombogenic and antithrombogenic factors on the graft surface was restored over a short period of time.

Animals↗
PubMed1998

Contraction of experimental skin flaps.

Contraction of experimental skin flaps in loose-skinned animals is a well-known but underestimated phenomenon that in fact may vary in different circumstances and complicate the calculations of survived and necrosed areas. A standard abdominal island skin flap design in the rat was used in this study to investigate the difference between the contraction rates of necrotic and survived tissues, and to determine its significance in the experimental models. The abdominal island skin flap was based on the inferior epigastric neurovascular bundles, and it extended from the pubis to the xiphoid and between the both midaxillary lines. The study was conducted in two steps. In the first step, contraction rates of completely necrosed (both pedicles severed) and completely survived (vascular pedicles were intact on both sides either with or without a nerve supply) flaps were assessed in 45 animals. After 1 week, area loss was highly significant in both necrosed and survived flaps (p < 0.001). The rate of contraction was significantly higher in necrosed tissues than in survived tissues (p < 0.001), and it was also significantly higher in the neurovascular flaps than in the denervated flaps (p < 0.05). The contraction of all flaps occurred in the vertical dimension, whereas the horizontal dimension stayed almost the same. In the second step of the study, a unilateral, pedicled abdominal flap was used, which had a constant necrotic zone on the nonpedicled half, either with or without a nerve supply in 30 animals. After 1 week the pedicled halves of all flaps were significantly larger than the nonpedicled halves (p < 0.001). Although the total area loss was higher in the neurovascular flaps than the denervated flaps, the difference was not significant statistically (p > 0.05). There was no statistically significant difference between the areas of necrosis seen in both groups when it was expressed as a proportion of the total flap area (p > 0.05). However, this insignificant difference became significant when the amount of necrosis was expressed as a proportion of only the nonpedicled flap half, favoring the denervated flaps (p < 0.005). It appears in this study that ultimate proportions of surviving and necrosed tissues may be inconsistent owing to the variable contraction rates of these tissues, and misleading conclusions may appear during the assessment of given treatment modalities.

Abdomen↗
PubMed1998

Effects of DPDPE (a specific delta-opioid receptor agonist) and naloxone on hypothalamic monoamine concentrations during the pre-ovulatory LH surge in the rat.

We have investigated the inter-relationship between the opioid and aminergic systems in the control of secretion of the pro-oestrous LH surge and the involvement of delta-opioid receptor subtypes in this process. Conscious female rats bearing a cannula in the femoral artery were injected i.p. with a selective delta-opioid receptor agonist (DPDPE) either alone or with the opioid antagonist (naloxone) at 1300 h on the day of pro-oestrus. Blood samples were collected hourly between 1500 h and 1900 h, and plasma LH levels were measured by RIA. At the end of this period (1900 h), the animals were autopsied and the concentrations of the amines (noradrenaline (NA), dopamine (DA), 5-hydroxytryptamine (5HT)) and their metabolites (dihydroxyphenolglycol (DHPG) and 5-hydroxyindoleacetic acid (5HIAA), metabolites of NA and 5HT respectively) were determined by HPLC with electrochemical detection in the medial preoptic area, suprachiasmatic nucleus, median eminence and arcuate nucleus. DPDPE abolished the LH surge and concomitantly decreased hypothalamic NA and DHPG concentrations in all the areas examined. The levels of DA, 5HT and 5HIAA were also reduced in all hypothalamic regions studied, except DA and 5HIAA in the suprachiasmatic nucleus. Naloxone reversed these inhibitory effects of the delta-agonist. We conclude that activation of delta-opioid receptors may exert an inhibitory effect on LH release. The effect is probably an indirect one mediated by the monoaminergic systems, as they are suppressed by DPDPE in nearly all the hypothalamic regions studied.

Animals↗
PubMed1997

Nerve and tendon approximator.

A practical and simple approximating device, made from a plastic syringe and 2 needles, is described. It allows a safe, tension-free approximation of severed ends of nerves or tendons.

Humans↗
PubMed1996

An investigation on plasma progesterone levels during pregnancy and at parturition in the Ivesi sheep.

In this study, plasma progesterone concentrations in a total of 45 Ivesi sheep were investigated during pregnancy and at parturition. Blood samples were collected from all the sheep studied every 20 days commencing on the 30th day of pregnancy. Plasma progesterone levels were determined by radioimmunoassay. During the second half of the pregnancy, progesterone concentrations in the sheep giving birth to one, two and three lambs were 2.02 +/- 0.08 ng/ml, 3.24 +/- 1.18 ng/ml and 4.90 +/- 0.85 ng/ml, respectively. There was no significant variation in progesterone levels between sheep with male and female offspring. At parturition, plasma progesterone concentrations did not differ significantly between the animals. The present results indicate that plasma progesterone levels could be used not only to determine the pregnancy status of the animal but also to predict the number of fetuses after the second half of the pregnancy.

Animals↗
PubMedDate not supplied

Evaluation of neuronal damage following hypoxic-ischaemic brain injury in acute and early chronic periods in neonatal rats.

This study was undertaken to investigate the effects of neonatal cerebral hypoxic-ischaemic brain injury (HIBI) in acute and early chronic phases in the rat. HIBI was induced in 7-day-old rat pups by ligation of the right common carotid and then the pups were exposed to 1 h of hypoxia in 8% oxygen. They were divided into two groups: 1-day (acute phase, in the first 24 h) and 5-day (early chronic phase, 120 h). Neuropathological evaluation was performed using the hippocampus, cerebral cortex and basal ganglia on the coronal plane. The following values were obtained: (i) the ratio of the infarcted area; (ii) hemispheric atrophy/asymmetry; (iii) patchy lesions confined to the thalamus, caudate and putamen; (iv) the ratio of damaged neurons to all neurons; and (v) the percentage of apoptotic neurons relative to the total neurons in all brain areas. HIBI-induced global cerebral damage and cellular damage findings did not significantly differ between the two groups. However, they showed a tendency to recover/deteriorate in both acute and early chronic phases. The ratio of ipsi- and contra-lateral hemisphere infarct areas (20.7 and 15.7% vs. 40.1 and 26.7%, respectively), basal ganglia patchy lesion ratio (27.5 vs. 36.7%) and hemispheric atrophy/asymmetry (92.4 vs. 84.7%) were found to be lower in the rat pups in the chronic phase than those in the acute phase. In contrast, increases in the ratio of damaged neurons (16.7 vs. 13.3% in the cerebral and dorsal hippocampus, respectively) and in the ratio of apoptotic neurons (ipsi-lateral: 18 vs. 6%; contra lateral hemispheres: 3.5 vs. 1.7%, respectively) were recorded. It is concluded that cellular damage tends to deteriorate (damaged and apoptotic neurons) while global damage (cerebral infarct and patchy damage) improves with the progression of HIBI. However, further studies are needed in order to elucidate this process.

Acute Disease↗
PubMedDate not supplied

Ultrastructural interrelationship between the pineal gland and the testis in the male rat.

The ultrastructural interrelationship between the pineal gland and testis was evaluated in the rat. Wistar rats were divided into 6 groups. Groups I and II were sham-orchidectomized and orchidectomized rats, respectively. Rats in group III were orchidectomized and daily injected with testosterone propionate (TP) for 1 month. Groups IV and V were sham-pinealectomized and pinealectomized, respectively. Group VI was pinealectomized and daily injected with melatonin for 2 months. All animals were anesthetized with ketamine for fixation by vascular perfusion. Pineal glands of groups I, II, and III and the testes of groups IV, V, and VI were removed and weighed. All specimens were examined by electron microscopy. Orchidectomy caused an increase of lipid droplets, cytoplasmic dense bodies, and lysosomes. Rough endoplasmic reticulum, Golgi apparatus, and mitochondria were extensive in the cytoplasm. TP administration to orchidectomized rats resulted in formation of less extensive lipid droplets and mitochondria. In pinealectomized rats, golgi complex, mitochondria, and enlarged smooth endoplasmic reticulum were extensive in the cytoplasm of Leydig cells. Formation of cytoplasmic secretory granules and osmiophilic bodies was observed. Testicular weight increased compared to group IV. Melatonin decreased testicular weight in comparison to group V and prevented ultrastructural changes. Pinealectomy and orchidectomy caused hyperactivity in Leydig cells and pinealocytes, respectively, which suggests a mutual relationship between the pineal gland and testis in the rat.

Animals↗
PubMedDate not supplied

Immunohistochemical, histological and ultrastructural evaluation of the effects of leptin on testes in mice.

This study was undertaken to examine the effects of leptin on testes in mice. For this purpose, 12 male mice were divided into two groups. Animals in Group I were designated as control. Mice in Group II were injected daily with leptin for 5 days. All animals were decapitated at the end of the experiment. The testes were removed and weighed out. Testicular tissue specimens were processed for light and electron microscopic examination and semi-quantitative evaluation of immunohistochemical testosterone staining. Intensity of immunostaining was determined on a scale between 0 (no staining) and 5 (heavy staining). For morphometric comparison, diameters of seminiferous tubules from each group were measured. In the leptin injected group, testicular weights and diameters of seminiferous tubules were significantly increased in comparison to control values. In light microscopic examination, an increase in secretory granules in the cytoplasm of Leydig cells was observed after leptin treatment. In the same group, distinct changes indicative of increased cell activation were seen in the ultrastructure of Leydig cells. Amount of mitochondria, lysosomes and cytoplasmic secretory granules were increased. Furthermore, an increase in extensiveness of rough endoplasmic reticulum was noted in this group. Immunohistochemical testosterone staining of the cytoplasm of Leydig cells was heavy (5+) in the leptin treated mice compared to mild score (2+) in the control mice. Additionally, heavy immunostaining of testosterone was also observed in the interstitial space after injection of leptin. The present findings indicate that testicular functions and synthesis of testosterone increase after administration of leptin.

Animals↗
PubMedDate not supplied

Influence of chronic morphine exposure on serum LH, FSH, testosterone levels, and body and testicular weights in the developing male rat.

Opiate abuse has been a matter of serious concern in male adolescents. This study investigates the effects of chronic morphine administration on serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone levels, testicular histology, and body and testes weight in developing male rats. Animals were subcutaneously injected with morphine (5 mg/kg) or saline (1 mL/kg) twice daily for 30 days. Body weight determinations and injections were carried out under light ether anesthesia. At the end of the experiments, the rats were decapitated and blood samples were collected. Serum levels of LH and FSH were measured. Chronic morphine administration significantly decreased decreased serum testosterone (p < .02) and LH (p < .01) levels, but not FSH release compared to controls. Morphine exposure reduced body weight (p < .01), but had no significant effect on the testicular weight. When the testicular tissue was histologically examined, structural features of the seminiferous tubules and Leydig cells were similar in both saline and morphine-treated animals. The results suggest that opiates affect testosterone release through the hypothalamo-hypophyseal-gonadal axis rather than by a local testicular mechanism. Chronic morphine exposure during sexual maturation may have long-term endocrine disturbances in male rats.

Animals↗
PubMedDate not supplied

Abdominal mass secondary to actinomyces infection: an unusual presentation and its treatment.

Abdominal actinomycosis may appear as an abdominal mass and/or abscess. This mass can mimic a malignant tumour. The diagnosis and management of abdominal actinomycosis will be discussed through a review of the literature and a case report from our own institution. The patient was a 17-year-old boy who presented with abdominal discomfort and a palpable right lower quadrant mass defined on CT scan. He underwent en bloc resection of the mass for a presumed diagnosis of tumour of uncertain type with intestinal involvement. The diagnosis was reversed, when histology revealed filamentous organisms consistent with actinomyces. He was treated with high dose penicillin for several weeks and was discharged from the hospital taking penicillin orally. Preoperative diagnosis of abdominal actinomycosis is difficult. An accurate diagnosis is always obtained in a histological or microbiological examination, often requiring surgical resection. Recognition is important because successful treatment requires combined surgery and prolonged penicillin treatment.

Abdominal Pain↗