Esra Erdemli

Temporoparietal fascia : An anatomic and histologic reinvestigation with new potential clinical applications

Temporoparietal fascia constitutes a very important structural unit from both an aesthetic and a reconstructive surgical point of view. A histologically supported anatomic study was conducted for the reappraisal of the anatomic relationships and clinical application potentials of the data obtained. Anatomy of the temporoparietal fascia was investigated on 20 sides from 10 cadavers. After dissections, necropsies were obtained to demonstrate histologic features of the temporoparietal fascia. The outer part of the temporoparietal fascia is continuous with the superficial musculoaponeurotic system (SMAS) in the inferior border and with orbicularis oculi and frontalis muscles in the anterior border. Therefore, plication of the temporoparietal fascia can increase tightness of the SMAS, orbicularis oculi, and frontalis muscle in rhytidectomy. The frontal branches of facial nerve were noted to course parallel to the frontal branch of the superficial temporal artery, lying deeper to the temporoparietal fascia within the innominate fascia. In the view of these findings, conventional subfascial dissection, which is performed to protect frontal branches of the facial nerve, is not reasonable during the temporal part of rhytidectomy. Careful subcutaneous dissection just under the hair follicles is more appropriate to avoid nerve injury and also provides excellent exposure of the temporoparietal fascia for plication in rhytidectomy with protection of the auriculotemporal nerve and the superficial temporal vessels. Furthermore, two layered structures of the temporoparietal fascia are very suitable to insert a framework into the temporoparietal fascia for ear reconstruction to eliminate some of the shortcomings of Brents technique. A thin muscle layer was also noted within the outer part of the temporoparietal fascia below the temporal line; the term “temporoparietal myofascial flap” would, therefore, be more accurate than “temporoparietal fascial flap.” Finally, the innominate fascia and the deep temporal fascia can be elevated with the two layers of the temporoparietal myofascial flap to obtain a well‐vascularized, four‐layered myofascial flap based on the superficial temporal vessels. This multilayered flap can be used to reconstruct all defects when fine, pliable, thin, multilayered flaps are required. (Plast. Reconstr. Surg. 105: 40, 2000.)

Effects of cryopreservation on sperm parameters and ultrastructural morphology of human spermatozoa

PurposeCryopreservation of sperm is a widely used technique to maintain and protect the fertility in various occasions such as infertility and malignancy treatments. This study aims to reveal the effects of freezing and thawing on human spermatozoa.Materials and methodsTo evaluate the effects of freeze–thawing, semen samples were evaluated by light microscopy by means of morphology, motility and viability, by scanning and transmission electron microscopy for detailed ultrastructural changes.ResultsAfter cryopreservation, a significant decrease in spermatozoa viability was observed (p < 0.01). Group a, b and c motility according to World Health Organization criteria decreased considerably (p < 0.05, p < 0.01, p < 0.05, respectively), whereas there was a substantial increase in group d motility. A strong correlation between rise in number of immotile spermatozoa and decrease in viability was also noted (r = −0.848, p < 0.01). Post-thaw light microscopic studies revealed a considerable decrease in rate of normal spermatozoa (p < 0.05). A considerable decline in the rate of normal sperm was also observed by TEM (p < 0.05). Statistically, acrosomal changes and subacrosomal swelling were found to be significantly increased (both p < 0.05), where the latter appears to be a novel finding in literature.ConclusionCryopreservation has deleterious effects on spermatozoa, especially on plasmalemma, acrosomes and tails. Electron microscopy is the ultimate modality to investigate spermatogenic cells.

Functional Structure of Adipocytes Differentiated from Human Umbilical Cord Stroma‐Derived Stem Cells

It has been previously demonstrated that human umbilical cord stroma‐derived stem cells (HUCSCs) are competent to differentiate into adipocytes. However, controversies have arisen as to whether HUCSCs can become mature adipocytes or not, and to what extent these cells can be induced in adipogenic pathway. Here, we extensively analyzed their adipogenic potency with a structural and functional approach by determining lipid formation dynamics in concordance to adipocyte‐specific markers. During a 35‐day period, HUCSCs respond to adipogenic induction, at which point 88% of cells exhibited multilocular lipid granules (LGs) having a mean diameter of 3 μm in round‐shaped, F‐actin‐poor cells. Although the 1st week of induction did not generally display typical lipidogenic phenotypes, the degree of adipogenesis was dissected and confirmed by mRNA expressions of peroxisome proliferator‐activated receptor γ, C/EBP‐β, sterol regulatory element‐binding transcription factor 1, adipophilin, stearoyl‐CoA desaturase, glycerol 3‐phosphate dehydrogenase 1, LIPE, adiponectin, and leptin. All markers tested were found elevated in various amounts (3–70‐fold) around day 7 and reached a plateau after day 14 or 21 (5–335‐fold). Perilipin as a surface protein around the LGs was confined exclusively to the enlarging LGs. Conclusively, we propose that after the termination of proliferation, HUCSCs possess the biochemical and cellular machinery to successfully differentiate into maturing adipocytes under adipogenic conditions, and this feature will ultimately allow these fetus‐derived stem cells to be used for various therapeutic or esthetic purposes.

The contribution of vitamin C to healing of experimental fractures.

Abstract The benefits of various minerals and vitamins on fracture healing have been demonstrated in animal models. Vitamin C is an essential substance in fracture healing but has not been studied previously on an experimental basis. Sixteen rats were grouped randomly into control and vitamin C-supplemented groups. The right tibias of all rats were fractured by digital manipulation. One group received single high dose of vitamin C intramuscularly. On the 5th, 10th, 15th, and 20th days, two rats from each group were killed and the tibias examined under light microscopy. It was seen that the vitamin C-supplemented group went through the stages of fracture healing faster compared with the control group.

Astrocytes are More Resistant to Focal Cerebral Ischemia Than Neurons and Die by a Delayed Necrosis

Several recent reports proposed that astrocyte death might precede neuronal demise after focal ischemia, contrary to the conventional view that astrocytes are more resistant to injury than neurons. Interestingly, there are findings supporting each of these opposing views. To clarify these controversies, we assessed astrocyte viability after 2‐h middle cerebral artery occlusion in mice. In contrast to neighboring neurons, astrocytes were alive and contained glycogen across the ischemic area 6 h after reperfusion, and at the expanding outer border of the infarct at later time points. These glycogen‐positive astrocytes had intact plasma membranes. Astrocytes lost plasmalemma integrity much later than neurons: 19 ± 22 (mean ± standard deviation), 58 ± 14 and 69 ± 3% of astrocytes in the perifocal region became permeable to propidium iodide (PI) at 6, 24, 72 h after ischemia, respectively, in contrast to 81 ± 2, 96 ± 3, 97 ± 2% of neurons. Although more astrocytes in the cortical and subcortical core regions were PI‐positive, their numbers were considerably less than those of neurons. Lysosomal rupture (monitored by deoxyribonuclease II immunoreactivity) followed a similar time course. Cytochrome‐c immunohistochemistry showed that astrocytes maintained mitochondrial integrity longer than neurons. EM confirmed that astrocyte ultrastructure including mitochondria and lysosomes disintegrated much later than that of neurons. We also found that astrocytes died by a delayed necrosis without significantly activating apoptotic mechanisms although they rapidly swelled at the onset of ischemia.

Lysosomal rupture, necroapoptotic interactions and potential crosstalk between cysteine proteases in neurons shortly after focal ischemia.

Ischemic cell death is a complex process and the initial distinction between apoptosis and necrosis appears to be an oversimplification. We previously reported that in ischemic neurons with disrupted plasmalemma, apoptotic mechanisms were also active. In the present study, we investigated cellular co-localization of another necrotic feature, lysosomal rupture, with apoptotic mechanisms in the mouse brain and assessed the potential interactions between cysteine proteases. The lysosomal enzymes were spilled into the cytoplasm 1-4h after ischemia/reperfusion, suggesting that lysosomal membrane integrity was rapidly lost, as occurs in necrosis. The same neurons also exhibited caspase-3 and Bid cleavage, and cytochrome-c release. Caspase-3 activity preceded cathepsin-B leakage in most neurons, and declined by 12h, while lysosomal leakage continued to increase. Concurrent inhibition of cathepsin-B and caspase-3 provided significantly better neuroprotection than obtained with separate use of each inhibitor. These data suggest that necrotic and apoptotic mechanisms may act both in concert as well as independently within the same cell beginning at the onset of ischemia to ensure the demise of damaged neurons. Therefore, combined inhibition of cysteine proteases may abrogate potential shifts between alternative death pathways and improve the success of stroke treatments.

Morphologic Evidence of Apoptosis in Childhood Acute Myeloblastic Leukemia Treated with High-Dose Methylprednisolone

We have previously demonstrated that various subtypes of AML children respond to high-dose methylprednisolone (HDMP; 20-30 mg/kg/day) which could induce in vivo differentiation of myeloid leukemic cells to mature granulocytes. In this study we have evaluated whether apoptosis occurs in AML cells of patients treated by HDMP using morphological criteria. For light and electron microscopic examination bone marrow aspirates were obtained four days and two weeks after methylprednisolone (30 mg/kg/day) treatment from two children with newly diagnosed AML (AML-M3 and AML-M4). In both patients maturation of leukemic cells has previously been reported four days (in patient with AML-M3) and two weeks (in patient with AML-M4) after HDMP treatment. Electron microscopy revealed the characteristic ultrastructural changes of various stages of apoptosis four days after HDMP treatment in a case with AML-M3. Morphologic evidence of apoptosis induced by HDMP were also detected on Wright-stained and toluidine blue stained semithin sections of BM preparations in a patient with AML-M4 and AML-M3 respectively. These findings suggest that HDMP which could induce in vivo terminal differentiation in myeloid leukemic cells is also able to induce apoptosis in patients with AML. The possibility of HDMP-induced apoptosis should be evaluated in a larger series of patients with AML and other types of malignant tumors.

Osseointegration in arthroplasty: can simvastatin promote bone response to implants?

Cementless fixation depends on bone ingrowth for long-term success. Simvastatin as a lipid lowering agent has been demonstrated to have osteoanabolic effects. This study was designed to measure the possible effect of simvastatin on implant osseointegration. Bilateral femoral implantation of titanium cylinders was performed in 20 rabbits. Blood lipid levels were measured pre- and postoperatively. Scanning electron microscopy (SEM) was used to measure the percentage of the surface of each implant in contact with bone and mechanical pull-out testing was performed. The blood lipid levels were significantly reduced in the simvastatin group. Histomorphometric examination revealed increased bone ingrowth and mechanical examination showed increased interface strength in the simvastatin group. Mechanical and histological data showed superior stability and osseous adaptation at the bone/implant interface for the simvastatin group. We conclude that simvastatin has potential as a means of enhancing bone ingrowth, which is a key factor in the longevity of cementless implants.RésuméLa fixation d’une prothèse sans ciment dépend de la réhabitation osseuse. La Simvastatine est un agent lipidique qui a un effet ostéo anabolique. Cette étude a pour but de montrer les effets de la Simvastatine sur l’ostéo intégration osseuse. Matériel et méthode : une implantation de cylindres de titane a été réalisée sur les deux fémurs de vingt lapins. Le taux de lipide a été mesuré en pré et post opératoire. L’examen en microscopique électronique a mesuré le pourcentage de la surface de réhabitation et des essais d’arrachage ont également été réalisés. Résultats : le niveau des lipides sanguins est réduit de façon significative dans le groupe de Simvastatine. L’histomorphométrie osseuse montre la croissance, l’orientation de la réhabitation et les tests mécaniques, l’augmentation de l’interface avec augmentation des forces nécessaires pour l’arrachage. En conclusion, les données mécaniques et histologiques montrent une stabilité supérieure dans le groupe Simvastatine. Nous pouvons conclure que la Simvastatine a un potentiel d’augmentation de la réhabitation osseuse facteur clé du succès à long terme des implants sans ciment.

Effects of recombinant human erythropoietin on mandibular distraction osteogenesis.

PURPOSE To evaluate the effects of subcutaneous administration of recombinant human erythropoietin (rHuEPO) on regeneration formation and quality during mandibular distraction osteogenesis. MATERIALS AND METHODS Sixteen adult male New Zealand rabbits were used in this study. Ethical approval was obtained from the Animal Research Institute of Selcuk University, Konya, Turkey. Subjects were randomly divided into 2 groups. Distraction osteogenesis (DO) was performed with a custom-made distractor on the left mandibles of rabbits. In the experimental group, 4 doses of 150 IU/kg rHuEPO were administered at 48-hour intervals. The first dose was given immediately after surgery. Control subjects received 0.5 mL/kg isotonic solution in the same manner. After 2 days of latency, mandibles were distracted 1 mm/day at 12-hour intervals for 5 days. A 5-mm lengthening was achieved. All animals were sacrificed after 30 days of consolidation. Afterward, samples were prepared for histomorphometric evaluation of newly formed bone area. RESULTS The number of osteoblasts and blood vessels was significantly higher, whereas the number of osteoclasts was significantly lower, in the experimental group than in the control group (P < .05). In the experimental group, the area of new bone formation was greater than in the control group (P < .05). Moreover, fibroblast and collagen numbers per unit area were higher in the experimental group. However, this finding was not statistically significant (P > .05). CONCLUSION The subcutaneous administration of rHuEPO improves the rate and quality of bone-healing during distraction osteogenesis. However, the short-term favorable effects of rHuEPO in this study should be extended with long-term investigations before clinical application.

Effects of methylprednisolone on human myeloid leukemic cells in vitro

We have demonstrated previously that high‐dose methylprednisolone treatment induces differentiation and apoptosis of leukemic cells in patients with different morphological subtypes of acute myeloblastic leukemia (AML) in vivo. In the present study, we investigated the in vitro effects of high (10−3 M) and low (10−6 M) concentrations of methylprednisolone (MP) on freshly isolated bone marrow leukemic cells from nine newly diagnosed patients with AML by light and electron microscopy (EM) and agarose gel electrophoresis. A marked increase in MP‐induced apoptosis of leukemic cells, with a maximum effect at 24 hr of exposure to both low and high concentrations of MP (10−6 M and 10−3 M), was demonstrated by light microscopy in cultures of four (three with AML‐M1 and one with AML‐M7) of the nine patients. In three cases, the increase in the number of apoptotic cells induced by high‐concentration MP was approximately twice that observed when the lower concentration was used. A few apoptotic cells were detected in the cultures from the other five patients. However, a typical DNA ladder pattern of apoptosis was observed on gel electrophoresis of MP‐treated leukemic cells from one patient (AML‐M1) after 2 hr of incubation with both high‐ and low‐MP concentrations. In two patients, a nonspecific DNA smear was observed only when high‐concentration MP was used. The increase in differentiated leukemic cells induced by MP was also dose dependent, and was observed in cultures from all but one patient. Morphological features of apoptosis and differentiation were also confirmed by EM studies. The results of the present study, together with our previous clinical experience, suggest that MP, especially at high doses, could have a significant role in the treatment of some AML patients by inducing apoptosis and differentiation of leukemic cells. Am. J. Hematol. 60:255–259, 1999.