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Biomedical subjects

F Yilmaz

Publications and source records attributed to F Yilmaz.

At least 37 records · Page 2Linked to original sources
PubMed2000

Limb reconstruction with the callus distraction method after bone tumor resection.

The callus distraction method was applied to nine patients who were referred to us because of a bone tumor. Their mean age was 17 years and 3 months (range 7-37 years). Three were female, and 6 were male. All of the tumors were localised on the femur, and the histological diagnosis was two chondrosarcomas, one Ewing's sarcoma, three osteosarcomas, one giant cell bone tumor, and the remainder benign fibrous histiocytoma. The mean length of the defect after resection of the tumor was 11.5 (range 8-20) cm. Preoperative and postoperative chemotherapy were applied to patients with osteosarcoma and Ewing's sarcoma. The patients were followed up for 22 (range 15-30) months on average. The mean period of use of the external fixator was 12.5 (range 8-18) months. One patient suffered a tumour recurrence and died after 20 months. Complications included one deep infection, one skin invagination, and one premature consolidation and bone bridge in the defect area. All of the complications were successfully treated. Functional evaluation gave excellent results in four patients, good in three, and fair in two. This method can be used without any need for massive autogenous bone graft in repairing defects of any length and diameter produced after excision of the lesion and thus can be considered as an alternative to other techniques.

Adolescent↗
PubMed2000

Intracranial meningeal tumours in childhood: a clinicopathologic study including MIB-1 immunohistochemistry.

Primary tumours of the meninges with a relatively high tendency for malignant behaviour are uncommon in childhood. This study concerns 18 cases of meningeal tumours in children under the age of 16, of which 13 were meningiomas and five were other tumours arising in the meninges. Meningiomas showed a preponderance in females as in adult series, and the majority were supratentorial in localisation. The percentage of meningeal tumours and meningiomas among all brain tumours in our centre were 3.72% and 2.69%, respectively. Four out of 13 meningiomas were fibroblastic, four were transitional, one was meningothelial, two were psammomatous and two were papillary meningiomas. Seven (38.8%) out of 18 tumours showed anaplastic features, including two papillary meningiomas, two hemangiopericytomas, one mesenchymal chondrosarcoma, one pleomorphic sarcoma and one anaplastic meningeal tumour. Papillary meningiomas with hemangiopericytoma-like solid areas were seen frequently in our cases (15.3%). Meningoangiomatosis was associated with two meningeal tumours. MIB1 (Ki-67) labelling indices (LIs) ranged between 0% and 13.6% (mean 1.83%) in benign, and between 1% and 20% (mean 7.2%) in malignant tumour, including papillary meningiomas. Mean MIB-1 LIs were 5.61% and 1.14% in non-recurrent and recurrent cases, respectively. MIB-1 LIs showed significant differences between benign and malignant meningeal tumours but no significant correlation either with prognosis or recurrence. Despite the fact that brain tumours are among the most common neoplasms of childhood, meningeal tumours are rare lesions, accounting for less than 2% of published series of intracranial neoplasms in childhood [5, 8, 18, 24, 30, 32]. It has been suggested that the clinical and pathological characteristics of meningiomas in this age group differ from those of adults [14, 18, 24, 45]. Besides meningiomas, there are a few reports of other meningeal tumours in childhood and difficulties in differential diagnosis may arise within this group, especially in anaplastic tumours [11, 13, 32, 44, 46]. One of the major problems in meningiomas and some tumours arising in the meninges is the discordance that arises between the histologic appearance of the tumour and behaviour [4]. Several studies have attempted to determine the proliferation potential of meningiomas, including immunohistochemical labelling with monoclonal antibodies to Ki-67, proliferating cell nuclear antigen (PCNA), and bromodeoxyuridine (BUdR); flow cytometric DNA analysis; or argyrophilic nucleolar organizer regions (AgNORs) counting [9, 10, 15, 19, 22, 26, 31, 35, 53]. The studies concerning proliferation markers have contradictory results [9, 10, 15, 26, 31, 42, 53]. MIB-1 detects the same or a similar epitope as the original antibody Ki-67 and reacts with a proliferation associated antigen expressed in all active parts of the cell cycle, G1, S, G2 and M (mitosis), but not in the G0 or quiescent phases [7]. In this study we examined the clinicopathological characteristics and MIB1 values of 18 meningeal tumours in children under the age of 16 years within the last 25 years (from 1970 to 1995).

Adolescent↗
PubMed2000

Penetration of the pulp chamber by bleaching agents in teeth restored with various restorative materials.

It is thought that externally applied bleaching agents may penetrate into the pulp chamber. This study was conducted to evaluate the diffusion of peroxide bleaching agents into the pulp chamber of teeth restored with various restorative materials. Sixty-five human extracted anterior maxillary teeth were separated into the 13 groups containing 5 teeth. Five teeth (control group) were not subjected to any cavity preparation and restoration. Standardized class V cavities were prepared in the other 60 teeth and restored using composite resin (Charisma), polyacid modified composite resin (Dyract), or resin-modified glass ionomer cement (Vitremer). All teeth were sectioned 3 mm apical to the cementoenamel junction to remove the intracoronal pulp tissue, and the pulp chamber was filled with acetate buffer to absorb and stabilize any peroxide that might penetrate. Vestibular crown surfaces of teeth in the experimental groups were subjected to four different bleaching agents for 30 min at 37 degrees C, whereas the teeth in the control groups were exposed only to distilled water. Then the acetate buffer solution in the pulp chamber of each tooth was removed, and the pulp chamber of each tooth was rinsed with 100 ml of distilled water twice. Leukocrystal violet and enzyme horseradish peroxidase were added to the mixture of the acetate buffer and rinse water. The optical density of the resulting blue solution was determined spectrophotometrically and converted into microgram equivalents of hydrogen peroxide. Higher hydrogen peroxide concentrations resulted in a higher pulpal peroxide penetration. The highest pulpal peroxide penetration was found in resin-modified glass ionomer cement groups, whereas composite resin groups showed the lowest pulpal peroxide penetration.

Acetates↗
PubMed2000

Uterine adenosarcoma with rhabdomyosarcomatous overgrowth. Brief communication.

A case of a rhabdomyosarcomatous uterine adenosarcoma with sarcomatous overgrowth is presented. The rhabdomyosarcoma component constituted about 90% of the tumor. The patient died 5 years and 5 months after the operation. Rhabdomyosarcomatous uterine adenosarcoma even with a sarcomatous overgrowth does not seem to be more malignant than other adenosarcomas.

Adenosarcoma↗
PubMed2000

The effects of natural ostium and nasoantral window on mucosal regeneration after maxillary sinus surgery in rabbits.

The aims of the study were to investigate the effects of natural ostium and the nasoantral window on the mucosal regeneration after maxillary sinus surgery and to detect the changes in the mucociliary clearance during regeneration process. Twenty-eight rabbits were studied. In the study group consisting of 21 rabbits, the mucosa of each right maxillary sinus was totally removed, natural ostium was occluded with bone-wax and a nasoantral window was created, while the left sinus mucosa was removed and the natural ostium was left open without creating a nasoantral window. Maxillary sinus mucosa taken during surgery was investigated by light and electron microscopy. The study group was divided into three subgroups. The first group was followed for 2, the second for 4, and the last group for 8 weeks. At the end of these periods, the mucociliary function was evaluated scintigraphically using 99mTc-Human serum albumin. Following this investigation mucosal biopsies were taken from the right and left sinuses and the rabbits were sacrificed. In the control group consisting of 7 rabbits a small hole was opened in the anterior wall of the maxillary sinus of each rabbit and the scintigraphic evaluation was performed for this group at the end of each follow up period as well. In the histopathologic investigation, no difference was found between the natural and the nasoantral window using light microscopy, but there was a difference between them in the electron microscopic findings (p < 0.05, Chi-square test). The scintigraphic, light and electron microscopic findings and gross appearances of the sinuses are discussed.

Animals↗
PubMed2000

The effects of sialoadenectomy & flutamide on skin development.

BACKGROUND: Epidermal growth factor is a low molecular weight polypeptide with 53 amino acids and is known to stimulate cell proliferation and differentiation in a wide range of tissues. The submandibulary gland in the mouse is a rich source of epidermal growth factor and decreased plasma epidermal growth factor levels have been observed after sialoadenectomy (removal of the submandibular glands). Furthermore. there is evidence that epidermal growth factor stimulates spermatogenesis and reverses antiandrogen induced cryptorchidism. OBJECTIVE: In the present study, the teratogenic effects of sialoadenectomy and antiandrogen (flutamide) administration on rat skin were investigated histologically. MATERIALS & METHODS: Thirty Spraque-Dawley female rats were separated into three groups (n = 10), a control (sham-operated) and two experimental groups. The first experimental group of rats were subjected to sialoadenectomy in order to create maternal EGF deficiency one month before copulation. The second experimental group of rats were given flutamide (10 mg/100 g) for ten days during pregnancy. Three months after birth, a penile skin biopsy was taken from respective offspring in all groups. RESULTS: A statistically significant reduced body weight and length were noted in the first group of litters (maternal EGF deficient) and in the flutamide administered group when compared to the control group. Atrophic epidermis and dermal adnexa were observed histologically as the teratogenic effects of sialoadenectomy and flutamide administration on rat skin development. CONCLUSION: Epidermal growth factor is a key hormone for skin development and antiandrogen administration may insult this process by interfering with epidermal growth factor metabolism.

Androgen Antagonists↗
PubMed1999

Determination of serum bile acids routinely may prevent delay in diagnosis of total parenteral nutrition-induced cholestasis.

BACKGROUND/PURPOSE: Early diagnosis of development of cholestasis is a current major problem for patients receiving total parenteral nutrition (TPN). Conventional tests for hepatic function such as serum transaminases and alkaline phosphatase do not often reflect simultaneously histopathologic changes of the liver. The aim of this study is to find out the relationships between conventional hepatic function tests, total serum bile acid concentrations (TSBA), and the histopathologic changes in the liver during TPN administration in rats. METHODS: Forty Albino rats were divided into four experimental groups, each consisting of 10 rats, as follows: control group (C), 0.9% saline for 14 days; T7 group, TPN for 7 days; T14 group, TPN for 14 days; T7O7 group, TPN for 7 days and then 0.9% saline for the next 7 days. All solutions were administered by infusion through intraperitoneal catheter in two equal doses. During the experiment, rats also maintained on rat chow and water ad libitum. Levels of serum glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, alkaline phosphatase, and TSBA were measured. Liver was evaluated histopathologically by light microscope and then Morphological Cholestasis Index (MCI) was calculated. RESULTS: Cholestasis was present in all experimental groups except control. Levels of transaminases and alkaline phosphatase were not correlated with the histopathologic changes (P > .05), but TSBA concentrations were correlated with MCI in all groups (P< .01). TSBA concentrations and MCI in all groups also were correlated with the duration of exposure with TPN (P< .01). CONCLUSIONS: Measurement of TSBA seems to be more sensitive in early diagnosis of TPN-induced cholestasis. Therefore, periodical determination of TSBA during TPN administration can be done routinely.

Animals↗
PubMed1999

Effects of otitis media with effusion on the vestibular system in children.

Middle ear effusion has been considered the most common cause of vestibular disturbance in children. However, there have been only a few studies on vestibular disturbance in children with otitis media with effusion. We studied the vestibular systems of 30 children with otitis media with effusion aged 8 to 13 years and compared the results with 15 age- and sex-matched controls. A questionnaire relating to vestibular disturbance was given to patients and their parents. Spontaneous nystagmus and positional nystagmus were recorded by electronystagmography as diagnostic tests of the vestibular system. Romberg's and past-pointing tests were performed on children with otitis media with effusion and controls. After vestibular tests were completed, myringotomy was performed, and a ventilation tube was inserted. The questionnaire and the vestibular tests were repeated after the operation and during the first month after surgery. Our study showed that there was a history of vestibular disturbance in 33% of children with otitis media with effusion. Electronystagmography and Romberg's test findings demonstrated that 33% of the children had vestibular dysfunction (p < 0.05). After myringotomy with ventilation tube insertion, vestibular test results returned to normal, and symptoms related to vestibular disturbance improved. These findings confirm the assumption that middle ear effusion may affect the vestibular system, which can be resolved after myringotomy with ventilation tube insertion.

Acoustic Impedance Tests↗
PubMed1999

The in vitro hepatic metabolism of 1-phenyl-2-(2-benzothiazolinone-3-yl)ethanone and their reduced derivatives.

The in vitro hepatic microsomal metabolism of 1-phenyl-2-(2-benzothiazolinone-3-yl)ethanone (I) and (+/-)-1-Phenyl-2-(2-benzothiazolinone-3-yl)ethanol (II) was studied using both rat microsomal preparations and soluble fractions fortified with NADPH. These two substrates and their potential dealkylation metabolite 2-benzothiazolinone were synthesized and their structures were elucidated by spectral methods. The results showed that (I) was metabolised to (II), the corresponding alcohol by reduction. More alcohol metabolite was observed with microsomes than those obtained with the soluble fractions. No dealkylation of (I) was observed in the experiments using both microsomes and soluble fractions. (II) was metabolised to (I), the corresponding ketone by oxidation. However, compared to the metabolism of (I), more ketone metabolite was observed with soluble fractions than microsomes. (II) was also dealkylated to (III) with only soluble fractions but no dealkylated metabolites were found in the microsomes. In addition, a common unknown metabolite was observed with each substrates.

Analgesics↗
PubMed1999

The in vitro hepatic microsomal metabolism of N-benzyladamantanamine in rats.

The metabolism of N-benzyladamantanamine (NBAD) was studied in vitro using rat hepatic microsomal preparations. The substrate and proposed metabolites were synthesized and characterized using spectroscopic techniques and separated using a reverse phase HPLC system. NBAD was incubated with rat microsomal preparations, extracted into DCM in the presence of NaCl and evaporated under a stream of nitrogen. The results from HPLC studies showed that NBAD produced the corresponding nitrone and hydroxylamine. This experiment also revealed that dealkylation occurred. No metabolites were observed which corresponded to authentic amide or oxaziridine. The reactions required a microsomal enzyme source and NADPH as a cofactor. The results indicate that the nitrone observed as a metabolite of NBAD is not an intermediate leading to the formation of an oxaziridine and hence an amide, under careful experimental conditions excluding light.

Amantadine↗
PubMed1999

The in vitro hepatic microsomal metabolism of methyl 2-(2(3H)-benzoxazolone-3-yl)acetate in rats.

The in vitro hepatic microsomal metabolism of methyl 2-(2(3H)-benzoxazolone-3-yl)acetate (I) was studied using hepatic washed rat microsomal preparations fortified with NADPH. The substrate (I) and its potential hydrolytic metabolite 2-(2(3H)-benzoxazolone-3-yl)acetic acid (II) and 2(3H)-benzoxazolone (III), a potential dealkylation metabolite, were separated using a reverse phase HPLC system which consisted of a C18 column and a mobile phase of acetonitrile: 0.02 M phosphate buffer (30:70, final pH 7) at a flow rate of 1 ml/min with UV detection at 254 nm. The substrate (I) was incubated with rat microsomal preparations, extracted into DCM, and finally evaporated under nitrogen. The results from HPLC studies showed that (I) was metabolised to (II) and (III) by rat microsomes in the presence of NADPH.

Acetates↗
PubMed1999

Protruding urethral leiomyoma obscuring vaginal introitus: case report.

Leiomyoma is quite rare in the female urethra. We report an additional case to 29 reported in the literature. A multiparous woman presented with a complaint of a gradually enlarging mass causing dyspareunia for the last seven months. The mass was originating from the upper part of the distal urethra with a relatively thin stalk covered by squamous epithelia, and immunohistopathological examination confirmed it as leiomyoma.

Adult↗
PubMed1998

Aluminum in total parenteral nutrition solutions produces portal inflammation in rats.

BACKGROUND: Aluminum contaminates parenteral nutrition solutions and accumulates in bone and liver of patients receiving total parenteral nutrition therapy. Although previous reports have shown that parenteral administration of aluminum in pharmacologic doses to rats results in the production of elevated total serum bile acid concentrations alone or in combination with decreased bile flow, they have failed to demonstrate any abnormalities in the histologic appearance of liver tissue. The effects of aluminum in total parenteral nutrition and of aluminum chloride on total serum bile acid concentrations, aluminum contents of the liver, and histopathologic changes in the liver were studied in rats. METHODS: The aluminum concentrations in the aluminum chloride solution and total parenteral nutrition formula were equal (300 microg/l). They were given intraperitoneally as follows: control group, 0.9% saline for 14 days; T7 group, total parenteral nutrition for 7 days; A7 group, aluminum chloride for 7 days; A14 group, aluminum chloride for 14 days; T7A7 group, total parenteral nutrition for 7 days and aluminum chloride for the next 7 days; and T7O7 group, total parenteral nutrition for 7 days and 0.9% saline for the next 7 days. Volumes of 0.9% saline, aluminum chloride, and total parenteral nutrition given to rats were equal. During the experiment, rats were maintained on rat chow and water ad libitum. Serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, alkaline phosphatase, and bile acid concentrations and aluminum content of the liver were measured. The liver was evaluated histopathologically by light microscope, and a morphologic portal inflammation index was calculated. RESULTS: Portal inflammation was present in all groups except the control group. The morphologic portal inflammation correlated with hepatic aluminum accumulation in all groups and was the highest in the T7A7 group. Levels of serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, and alkaline phosphatase did not correlate with the histopathologic findings, but serum bile acid concentrations correlated with morphologic portal inflammation and hepatic aluminum accumulation in all groups. Hepatic aluminum accumulation also correlated with the duration of exposure to total parenteral nutrition and aluminum chloride concentration. CONCLUSION: Aluminum in contaminating doses, not in pharmacologic doses, accumulates in the liver and can produce hepatobiliary dysfunction characterized by portal inflammation detectable in histologic examination of liver tissue.

Alanine Transaminase↗
PubMed1997

Level of conus medullaris in term and preterm neonates.

AIMS: To compare the levels of conus medullaris in preterm and term neonates; to show the time of ascent to normal; and to evaluate the babies with low conus medullaris levels for tethered cord syndrome. METHODS: Levels were assessed using ultrasonography in 41 preterm and 64 term neonates. RESULTS: In the preterm group the conus medullaris level in one infant (2.4%) was below L4. In three infants (7.2%) it was between L2 and L3 and in 37 infants (90.4%) it was above L2. In the term group it was below L4 in one baby (1.6%), between L2 and L3 in four (6.3%), and above L2 in 57 babies (92.1%). The difference in the conus medullaris levels between term and preterm neonates and genders was not significant. Two patients, one with a conus medullaris level at L4-L5, and the other at L2-L3, had Down's syndrome. CONCLUSION: The ascent of conus medullaris seems to occur early in life. It is important to follow up patients with conus medullaris levels at or below the 4th lumbar vertebra for the development of tethered cord syndrome.

Down Syndrome↗