Zeynep Kahveci

Pars plana vitrectomy and removal of the internal limiting membrane in the treatment of chronic macular oedema

BackgroundTo evaluate the results of pars plana vitrectomy with peeling of the internal limiting membrane (ILM) in eyes with chronic macular oedema.MethodsPPV with indocyanine green (ICG) assisted peeling of the ILM was performed in 33 eyes with diabetic (21 eyes) or non-diabetic (12 eyes) macular oedema. Postoperatively, resolution of macular oedema, improvement of visual acuity (VA) and complications were documented. The peeled membranes were submitted for light and transmission electron microscopic evaluation.ResultsThe mean follow-up time was 12.2 months. The macular oedema decreased or was resolved in 17 (81%) eyes in the diabetic group and in 11 (92%) eyes in the non-diabetic group. VA improved by at least 2 lines in 11 (52%) eyes in the diabetic group and in 7 (58%) eyes in the non-diabetic group. The difference between visual acuity improvements of the two groups was not statistically significant (P>0.05). However, in the diabetic group the difference of visual improvement between cystoid and diffuse type of macular oedema eyes was statistically significant (14% versus 71%, P=0.02). Light and transmission electron microscopy showed the presence of ILM in all specimens. During the follow-up period no recurrence of macular oedema or epiretinal membrane formation was observed.ConclusionPars plana vitrectomy with peeling of the ILM and epiretinal membrane leads to the resolution of macular oedema in the majority of eyes. This however, is not always associated with VA improvement. In diabetic eyes, cystoid type of macular oedema appears to be a poor prognostic factor for improved VA.

Microwave Fixation of Whole Fetal Specimens

This study compares microwave fixation of whole fetal specimens with conventional techniques performed at room temperature. All fetuses were obtained from the same pregnant rat; half of them were placed in neutral formalin for 15 min at room temperature, then irradiated for 2.5 min in a domestic microwave oven. The remaining fetuses were placed in neutral formalin at room temperature for 48 hr as a control. Both experimental and control groups were exposed to routine tissue processing for light microscopy and embedded in paraffin wax. Sections 5 microns thick were stained with hematoxylin and eosin. Our results showed that the microwave technique reduced the fixation time while providing thin sections that were equal to or better in quality than those in the control group.

A comparison of microwave heating and proteolytic pretreatment antigen retrieval techniques in formalin fixed, paraffin embedded tissues.

Antigen retrieval (AR) is a technique that re-exposes epitopes in formalin fixed, paraffin embedded sections and makes them detectable by immunohistochemistry. We compared the effects of two AR procedures, enzyme digestion and microwave heating, on immunostaining of vimentin and desmin in formalin fixed, paraffin embedded tissues. Our results showed that AR is necessary for vimentin and desmin immunostaining in tissues fixed in formalin for more than 48 h. With prolonged fixation times, microwave heating showed better results than enzyme digestion for AR. The same results were obtained using 1% zinc sulfate or Citra Plus solution as retrieval solutions for microwave heating. We recommend microwave heating for AR, because it is easier to use and produces better results compared to enzyme treatment.

Safranin O Staining Using a Microwave Oven

We investigated the effects of microwave irradiation on a safranin O staining method for paraffin sections of formalin fixed rabbit larynx. The control sections were stained according to the conventional method, and the experimental sections were stained in microwave oven for 10 sec at 360 W in Weigerts iron hematoxylin, and for 30 sec at 360 W in fast green and 0.1% safranin O staining solutions. Light microscopic examination of the sections revealed that the microwave heating did not adversely affect the staining properties of cartilage tissue compared to the conventional staining method. Small differences such as darker staining of the matrix and shrinkage of the cytoplasm was observed in some microwave treated sections. The present study revealed that microwave application can be used safely for the safranin O method with the advantage of reduced staining time.

Urethral reconstruction with autologous vein graft: an experimental study

There is no universally accepted material for urethral reconstruction. This study presents the results of segmental urethral replacement with a free graft of jugular vein in rabbits. Histological examination showed ingrowth of normal transitional epithelium into the venous endothelium. Retrograde urethrograms revealed an excellent result up to 300 days. Fistulas and infection occurred in 4/44 rabbits; these settled spontaneously. No structures or papillary hypertrophy were noted. Segmental urethral reconstruction with autologous vein graft is a simple technique with few complications and appears suitable for use in clinical cases.

Microwave-assisted antigen retrieval and incubation with cox-2 antibody of archival paraffin-embedded human oligodendroglioma and astrocytomas.

Immunohistochemistry is an important tool that is often used for the diagnosis of pathologies; however, the length of time required to process the tissue is relatively long. Furthermore, the quality and sensitivity of immunohistochemical staining is affected by formalin fixation which results in variable loss of antigenicity, known as masking effect. Here we assess the effect of microwave irradiation on the incubation time required to obtain high quality immunohistochemical staining for cox-2 using archival formalin-fixed, paraffin-embedded human oligodendrogliomas and astrocytomas. The results show that intermittent microwave irradiation during the incubation with the primary antibody reduced the time requirement to 5 min while the staining quality was indistinguishable from 1 or 24 h long incubations. Thus, the use of this procedure results in a significant saving of time which is important for a timely diagnosis of pathological conditions that await treatment.

A simple and rapid microwave-assisted hematoxylin and eosin staining method using 1,1,1 trichloroethane as a dewaxing and a clearing agent

The use and practicability of microwave-assisted staining procedures in routine histopathology has been well established for more than 17 years. In the study reported here, we aimed to examine an alternative approach that would shorten the duration of dewaxing and clearing steps of hematoxylin and eosin (H & E) staining of paraffin sections by using a microwave oven. Although xylene is one of the most popular dewaxing and clearing agents, its flammability restricts its use in a microwave oven; thus we preferred 1,1,1 trichloroethane, which is not flammable, as the dewaxing and clearing agent in the present study. In Group I and Group II (control groups), intestine was processed with xylene and 1,1,1 trichloroethane, respectively. The sections were then stained with H & E according to the conventional staining protocol at room temperature and subdivided into two groups according to the duration of dewaxing and clearing in xylene. In Groups III and IV (experimental groups) similar tissues were processed with xylene and 1,1,1 trichloroethane, respectively; however, sections from these groups were divided into four subgroups to study the period required for dewaxing and clearing in 1,1,1 trichloroethane, then stained with H & E in the microwave oven at 360 W for 30 sec. Our conventional H & E staining procedure, which includes dewaxing, staining and clearing of sections, requires approximately 90 min, while our method using 1,1,1 trichloroethane and microwave heating required only 2 min. Our alternative method for H & E staining not only reduced the procedure time significantly, but also yielded staining quality equal or superior to those stained the conventional way. Our results suggest that 1,1,1 trichloroethane can be used effectively and safely as a dewaxing and clearing agent for H & E staining in a microwave oven.

Rapid Bielschowsky silver impregnation method using microwave heating

The Bielschowsky silver impregnation method has been used extensively to demonstrate neuronal processes including dendrites, axons and neurofibrils. In this study, we examined the differences in the time required for and the staining quality of the Bielschowsky method for neuronal processes when microwave heating was used instead of processing at room temperature. For this purpose, a control group of sections stained according to the conventional method at room temperature was compared to an experimental group stained in a microwave oven at 180 W for 2, 4 and 1 min in 2% silver nitrate, ammoniacal silver nitrate and gold chloride, respectively. Light microscopic examination demonstrated that the normal structure was preserved in both groups and that there was no difference in the staining quality between the control and the microwave groups. In addition, staining time for this procedure was reduced to 8 min by using the microwave oven. Our study revealed that microwave irradiation can be used safely for Bielschowsky silver impregnation of neuronal tissues.

Effect of lyophilized heterologous collagen on new cartilage formation from perichondrial flaps in rabbits: an experimental study.

New cartilage formation originated from perichondrium has previously been researched in many clinical and experimental studies. 1–6 After these studies, the use of perichondrium for the repair of cartilage defects has been used clinically when enhancing neochondrogenesis has been found to be of great value in decreasing the recovery period. Collagen is the major protein of whole connective tissue, and in vitro positive effects of collagen matrices on neochondrogenesis have also been studied before. 7–9 In this experimental study, in vivo effects of heterologous collagen sponge in perichondrial neochondrogenesis were examined in an animal model, and acceleration and enhancement effects were observed.

Using microwave irradiation in Marchi's method for demonstrating degenerated myelin

Conventional methods for histological preparation of degenerated myelin are time-consuming and difficult. The purpose of our study was to shorten the time required for the procedure and to obtain better quality results for light microscopic demonstration of degenerated myelin in the central and peripheral nervous systems by using microwave irradiation. Rat brain and sciatic nerve were used for the study. The middle cerebral artery was occluded and the sciatic nerve was cut to produce myelin degeneration. Marchis method was used for staining degenerated myelin. Fixation for light microscopy that would take two days using the conventional procedure was completed in 16.5–18.5 min using microwave irradiation. While staining of degenerated myelin requires 10 days for the conventional Marchi method, we decreased it to 7 h for brain tissue and 1 h for sciatic nerve by using the microwave oven. Moreover, a better quality preparation was achieved in the groups stained under microwave irradiation than those prepared by the conventional method.