Biomedical subjects
Publications and source records attributed to O Ozen.
The electrohydrodynamic instability of the interface between two liquids with different physical and electrical properties in plane Poiseuille flow is used to form monodisperse droplets in a square channel. The drop size and formation rate are controlled by simply controlling the flow rates and the amplitude of the electric field applied across the channel.
Experimental evidence is provided to show the effect of gas phase dynamics on the onset of thermal convection and on the accompanying patterns in a silicone oil-air convecting bilayer. Very good agreement with three-dimensional calculations for linearized stability is obtained mostly for small and large gas heights. Reasons for this agreement as well as the results at intermediate gas heights are qualitatively explained from the perspective of well-established nonlinear analysis.
Kaposi's sarcoma (KS) is an angioproliferative condition that accounts for 6% of all malignancies in organ transplant patients. When we review the literature, the results of the studies comparing the different stages and the proliferative activity of the tumor are challenging. However, we found no previous study on Ki-67 protein expression in KS that correlates skin and organ lesions. In the current study, we investigated whether there is a correlation on the proliferative activity between skin and internal organ lesions in KS. Proliferative activity of 13 biopsy specimens of KS was assessed immunohistochemically using the monoclonal antibody MIB-1 (Ki-67). Mann-Whitney U test is used for statistical analysis and a P value < .05 was considered significant. Seven of 13 cases were skin and six were internal organ KS. For skin lesions, the mean MIB-1 proliferation index was 14.5%, and it was 13% for organ lesions. There was no significant association between skin and internal organ KS in regard to MIB-1 PI (P > .05). The findings suggested that the proliferative activity in KS does not differ in skin and organ lesions. On the other hand, it should be considered that the number of cases in our study was limited and further studies with a larger series are needed.
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Fibrous pseudotumor of the tunica vaginalis testis is an uncommon lesion of unknown pathogenesis. Although this reactive process of testicular tunics is benign, this usually is diagnosed after radical orchiectomy. The authors describe a case of fibrous pseudotumor of the tunica vaginalis testis associated with testicular infarction. To our knowledge, this is the first case presented with similar association, second case consisting predominantly of myofibroblasts and the fourth reported case encountered in childhood.
In the treatment of thoracal hydatid cysts, there is not an agreement whether the cyst cavity to be capitonnaged or not. In this retrospective study, it was aimed to compare the cases of capitonnaged and not capitonnaged thoracal hydatid cysts with regard to hospital stay and post-operative chest tube removal day. Documents of 15 patients operated for pulmonary hydatid cysts in our clinic were reviewed. In 7 cases pericystectomy and removal of germinative membrane was performed whereas in 8 patients capitonnage was added to the procedure. In all cases open airways were suture controlled and pleural cavity was drained with chest tube connected to waterseal system. Average hospital stay of capitonnaged cases was 8 days and of uncapitonnaged ones was 12 days. Thoracal drainage tubes were removed in an average of 4 post-operative days in capitonnaged cases and of 7 days in the others. Statistical analysis were made by Mann-Whitney U test. Difference between the hospital stays of the 2 groups were not significant, whereas it was significant statistically between chest tube removal days (p<0.05). Capitonnage shortens postoperative chest tube drainage period in pulmonary hydatid cysts, resulting in lower morbidity compared with the uncapitonnaged cases.
This study was conducted to evaluate the inhibin B with FSH and LH levels on spermatogenesis in varicocele patients. The study group consisted of 10 adolescent with left idiopathic varicocele of grade II and III. Blood specimens were obtained from dilated spermatic vein and peripheral vein simultaneously. Peripheral samples were also collected from 7 healthy children as controls. Inhibin B was measured with ELISA inhibin B kits. FSH and LH were analyzed by radioimmunoassay techniques. The results were analyzed using Mann-Whitney U and Spearman's rank tests. A value of p < 0.05 was considered significant. Peripheral FSH, LH and inhibin B levels were the same in the study and control group (p > 0.05). Mean inbibin B levels of spermatic vein were significantly higher than the control and peripheral blood of the study groups (p < 0.05). FSH, LH, and inhibin B levels correlated poorly each other (p > 0.05). Preoperative serum inhibin B concentration could not reliably predict a response to varicocelectomy, but the increase in inhibin B levels after treatment might suggest an improvement in testicular function.
Primary neoplasms of the pleura are rare tumors and the majority are generally mesotheliomas. Mesotheliomas are either localized and mostly benign, or diffuse and uniformly malignant neoplasms. Localised benign pulmonary mesothelioma (solitary fibrous tumor of the pleura) are originally thought to be a variant of diffuse pleural mesothelioma because they consists of a spindle cell stroma associated with branching tubular structures lined by cuboidal cells. Our case which is reported below shows the clinical spectrum of the more common benign variant. Clinical differential diagnosis of benign and malign mesotheliomas is not clear. Complete surgical resection is the preferred treatment for both types and usually curative with the benign mesothelioma. The localised pleural variant is benign in most cases, and it is even less common, constituting only 10% of all mesotheliomas [1]. The importance of localised benign mesothelioma is that it is almost impossible to differentiate from a malignant neoplasm preoperatively and it may occasionally recur, sometimes with a malignant change.
OBJECTIVE: Meningiomas for the most part are slow-growing benign tumors, but complete removal can be difficult and recurrence is an issue. The aim of this study was to re-evaluate tumors diagnosed as meningioma previously in our hospital, according to the latest World Health Organization classification. We also examined the relationships among parameters such as brain invasion, histological grade and Ki-67 and p53 expression in these tumors. MATERIALS AND METHODS: Meningioma biopsy specimens numbering 60 (48 grade I, 11 grade II, and 1 grade III tumors) were examined immunohistochemically using monoclonal antibodies for Ki-67 (MIB-1) and p53 protein. The MIB-1 labeling index (LI) for each tumor was calculated as a percentage based on the number of stained cells per total cells counted. The level of p53 expression in each sample was semiquantatively evaluated as < 1%, 1 - 10%, 10 - 70%, or > 70%. Any value > 1% was accepted as presence of p53 expression. RESULTS: Of the 60 meningiomas, 7 (11.7%) exhibited brain invasion. The mean MIB-1 LI values for the grade I and grade II tumors were 1.1% and 2.3%, respectively. The corresponding levels of p53 protein expression in these groups were 54.1% and 72.7%. The MIB-1 LI and the level of p53 expression in the one grade III meningioma were 6.7% and 10 - 70%, respectively. Histological grade was significantly correlated with MIB-1 LI and with p53 expression (p < 0.01 for both). Brain invasion was not correlated with histological grade, MIB-1 LI, or p53 expression. CONCLUSION: The results indicate that MIB-1 LI and p53 protein expression are good indicators of histological grade in meningioma and may be particularly valuable for distinguishing borderline atypical meningiomas. The number of cases was limited, but the findings also suggest that brain invasion is a prognostic parameter independent of grade, MIB-1 LI and p53 expression.