A Short Duration Transient Ischemia Induces Apoptosis in Retinal Layers: An Experimental Study in Rabbits

Purpose

To investigate retinal cell apoptosis in an experimental transient, short duration ocular ischemia model.

Methods

An experimental ischemia model, which simulates creating temporary high intraocular pressure to control intraocular bleeding during pars plana vitrectomy, was set up. Rabbits were randomly divided into three groups. Group 1 was the control group. In Group 2, intraocular pressure was increased to 97 mmHg for 5 minutes. In Group 3, intraocular pressure was increased to 97 mmHg for 10 minutes. After 24 hours, terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labeling assay was used to detect retinal apoptosis in rabbit eyes. Only nuclear staining in retinal cells was counted.

Results

Groups with 5 minutes and 10 minutes of ischemia showed significantly higher amount of ganglion cell layer apoptosis when compared with the control group (p<0.05). Light microscopy and standard hematoxylin-eosin did not show any significant damage in the retina cells.

Conclusions

Apoptotic cell death in the retinal cell layers occurs in temporary ischemia-reperfusion as early as 5 and 10 minutes duration.

Diagnostic and prognostic significance of image cytometric DNA ploidy measurement in cytological samples of cervical squamous intraepithelial lesions

OBJECTIVE

To study the DNA ploidy pattern of uterine cervical squamous intraepithelial lesions (SILs) and its diagnostic and prognostic significance.

METHODS

The study included 31 cases of SIL: 11 low-grade (LSIL) and 20 high-grade (HSIL). Feulgen-pararosaniline staining was performed on previously Papanicolaou-stained smears and a DNA image cytometric study was performed. An internal reference was used to calibrate the samples.

RESULTS

All 31 cases of SIL, either LSIL or HSIL, were non-diploid. Of the 11 cases of LSIL, four were tetraploid and seven were aneuploid, whereas, of the 20 cases of HSIL, four were tetraploid and 16 were aneuploid. Stemline aneuploidy was not a significant discriminator between LSIL and HSIL (P=0.32). Based on single-cell analysis, HSIL cases had significantly higher DNA content than LSIL cases (P<0.01). When a mean of 30% or more was used for the 6c-exceeding event (6cEE) value, the sensitivity and specificity to indicate HSIL were 83% and 64%, respectively, with a positive predictive value (PPV) of 81% and negative predictive value (NPV) of 65%. All HSIL cases were cervical intraepithelial neoplasia grade 2 or worse (CIN2+) on biopsy. In addition, cases which showed recurrence had more DNA content by single-cell analysis than those with an indolent clinical behaviour: P=0.04 and P=0.03 for LSIL and HSIL, respectively.

CONCLUSIONS

Image cytometric DNA analysis is a useful technique for diagnostic and prognostic purposes in uterine cervical SIL when appropriate 'c' values are used in single-cell analysis. We propose that a >6c DNA content of 30% is useful as a cut-off level for predicting cases with CIN2+ in DNA image cytometry of cervical smears.

The impact of bone marrow fibrosis on the outcome of hematopoietic stem cell transplantation

We retrospectively analyzed the data of 175 patients who underwent autologous (n = 69) or allogeneic hematopoietic stem cell transplantation (HCT) (n = 106) including 19 (27.5%) and 38 (35.8%) recipients who had bone marrow fibrosis (BMF) prior to transplantation, respectively. We investigated the effects of BMF on engraftment, graft-versus-host disease (GVHD), early posttransplant complications, and survival. Pretransplantation BMF did not delay engraftment and showed no impact either on early posttransplant complications or on the development of acute and/or chronic GVHD. Probability of 1-year overall survival (OS) and progression-free survival (PFS) of autologous HCT recipients were similar, namely 76.7% versus 88.6% (P > .005) and 26.33% versus 16.5% (P > .05) among patients with versus without fibrosis, respectively. In allogeneic HCT recipients, the probability of 1-year OS was 35.2% among patients with versus 48.9% among those without fibrosis (P = .004) PFS at 1 year was inferior among allogeneic HCT recipients with BMF: 27.8% versus 51.2% (P = .0008). Cox regression analysis revealed BMF to be independently associated with age, Sorror comorbidity index, primary disease, and disease status during HCT (P = .045).

P21 and Bax expression in cutaneous malignant melanomas: correlation with histologic prognostic parameters

In response to DNA damage, p53 accumulates and regulates expression of several genes, including cyclin-dependent kinase inhibitor p21. Cells then undergo p21 dependent cell cycle arrest, which allows DNA damage repair and apoptosis. Bax is a death promoter member of the bcl-2 family which plays a central role in the regulation and commitment to programmed cell death. Breslow thickness is the most important factor in predicting prognosis for cutaneous malignant melanoma. In order to define the role of cyclin dependent kinase inhibitors and apoptosis regulators in invasion of malignant melanoma we investigated the expression of p21 and bax proteins. We observed that significant high p21 expression was associated with increasing Breslow thickness (Spearman correlation analysis, p=0.01). Additionally, Clark level I and II tumours expressed significantly lower p21 positivity than Clark level III, IV and V (p=0.006). Similarly, thick tumors showed a higher bax expression (p=0.012). Our results suggested that the role of p21 expression is more complicated in melanocytic skin cancers and abnormal regulation or abnormal function of cell cycle regulators occurred in the development and progression of malignant melanoma. In order to understand the role of bax expression in thick malignant melanomas and invasion biology, comparative analytic studies with other apoptosis regulators are needed.

Inhibition of epidural scar tissue formation after spinal surgery: external irradiation vs. spinal membrane application

PURPOSE

The scar tissue that forms after lumbar dissection is a severe complication and a cause of lumbar and radicular pain. It was recently shown that radiotherapy could inhibit peridural fibrosis after laminectomy. In this study, the efficiency of external irradiation was compared with spinal membrane application.

METHOD AND MATERIALS

Thirty male New Zealand rabbits underwent L5 laminectomy. Ten rabbits each received a single fraction of 900-cGy external irradiation administered by 9-MeV electron beam 24 h after the surgery. Ten other rabbits each had spinal membrane applied during laminectomy. The remaining 10 rabbits constituted the control group. All of the rabbits were killed 30 days after the laminectomy. Axial histologic sections through the laminectomy defect were evaluated. Each specimen was scored for the extent and density of fibrosis and arachnoidal adherence.

RESULTS

The extent and density of fibrosis and arachnoidal adherence differed significantly between the control group and the treatment groups (p < 0.05). However, the extent and density of fibrosis and arachnoidal adherence did not differ significantly between the spinal membrane and irradiation groups (p > 0.05).

CONCLUSION

This preliminary study showed that high-single-fraction/low-total-dose administered postoperatively can successfully inhibit postsurgical epidural fibrosis as effectively as applied spinal membrane.

Association between the severity of heart failure and the susceptibility of myocytes to apoptosis in patients with idiopathic dilated cardiomyopathy

BACKGROUND

Bcl-2 proto-oncogene, an inhibitor of apoptosis and Bax proto-oncogene, an inducer of apoptosis play critical roles in the molecular circuit controlling apoptosis in cardiac muscle. The ratio of Bax to Bcl-2 proto-oncogene determines survival or death after an apoptotic stimulus. We speculated that susceptibility of myocytes to apoptosis determined as the Bax/Bcl-2 ratio might vary with the severity of heart failure.

METHODS AND RESULTS

We studied immunohistochemically 108 endomyocardial biopsy specimens from 30 patients with idiopathic dilated cardiomyopathy (mild heart failure, n=14; moderate or severe heart failure, n=16) with the use of Bcl-2 and Bax monoclonal antibodies. The expression of each protein was determined semiquantitatively as the fraction of myocytes labeled with specific monoclonal antibodies using a digital morphometric analysis system. Patients with mild heart failure showed significantly increased Bax/Bcl-2 ratio than the patients with advanced heart failure (1.59+/-1.26 vs. 0.34+/-0.43, P=0.002). The expression of Bcl-2 was found to be independent of the severity of heart failure whereas the expression of Bax was significantly higher in patients with mild heart failure compared to the patients with moderate or severe heart failure (52.1+/-29.3 vs. 21.6+/-22.4%, P=0.005). Additionally, Bax/Bac-2 ratio was inversely correlated with the mitral E-interventricular septum distance, left ventricular end-systolic and end-diastolic diameter.

CONCLUSION

The susceptibility of myocytes to apoptosis is significantly increased in the early phase of heart failure but it decreases with worsening of the disease due to depressed expression of Bax onco-protein. Increased myocyte susceptibility to apoptosis may have a role in the transition from mild heart failure to severe in patients with idiopathic dilated cardiomyopathy.

Heterotopic bone formation in two cases of colon carcinoma

Heterotopic bone formation is rare in the gastrointestinal tract. We here present the clinical and pathologic details of a 56-year-old male patient with mucinous adenocarcinoma of the colon and a 70-year-old male patient with colon metastasis previously operated on for signet-ring-cell carcinoma of the stomach who was treated with radiotherapy postoperatively. Both of them showed diffuse bone metaplasia. Heterotopic bone formation is usually present with mucin-producing benign or malignant tumors. The pathogenesis of osseous metaplasia is not well known; however, it is speculated that the extravasation of mucin may have a stimulatory role.

The effects of dimethylsulfoxide on experimental hepatic ischemia

AIMS

The aim of the study is to investigate the effects of dimethylsulfoxide (DMSO), a non-enzymatic free oxygen radical detoxifier, on the alterations observed during hepatic ischemia.

METHODS

Twenty four albino rabbits were entered into the study. DMSO (500 mg/kg) was administered through inferior vena cava following dissection of the portal triad and immediately prior to clamping. The alterations on liver glycogen, blood glucose, ALT, AST, LDH, intracellular ATP, GSH-px, SOD, MDA within the erythrocyte and hepatic tissue MDA were investigated.

RESULTS

In the control group, following ischemia, a reduction in blood glucose, hepatic glycogen and ATP levels within the cell and an increase in AST and LDH levels, MDA, GSH-px and SOD levels within the erythrocyte and hepatic tissue MDA level were observed (p < 0.01). In the study group, the blood glucose values increased at 30th minute following ischemia. The increase in LDH level was not statistically significant (p > 0.05). The increase in AST level was significantly lower when compared to the control group (p < 0.05). No effect was observed on ALT and ALP levels. DMSO lowered the reduction in hepatic glycogen level (p < 0.05), GSH-px (p < 0.01), MDA (p < 0.05) and ATP (p < 0.05) levels within the erythrocyte and hepatic tissue MDA level (p < 0.01) that were increased following ischemia. The increase in blood SOD level was not statistically significant (p > 0.05).

CONCLUSION

DMSO can be administered in attempt to prolong the duration of ischemia or to reduce the adverse effects of ischemia on the hepatic tissue during the existing ischemic period.

Isovolumic relaxation flow in patients with left bundle branch block and normal coronary arteriogram

The purpose of this study was to clarify the presence of isovolumic relaxation flow in patients with left bundle branch block and normal coronary arteriogram. Twenty-four patients with left bundle branch block and normal coronary arteriogram were examined by pulsed Doppler echocardiography and were compared with 20 age- and gender-matched healthy subjects. Impaired left ventricular relaxation was found in patients with LBBB. All 24 study patients showed isovolumic relaxation flow, but only 4 healthy subjects had isovolumic relaxation flow (p < 0.05). Peak velocity of the isovolumic relaxation flow ranged from 20-42 cm/s. In the study group, left ventricular systolic function was normal in 17 patients, and reduced in the remaining patients. At the end of this study, the presence of isovolumic relaxation flow which may be due to an abnormal septal motion was found in patients with left bundle branch block and normal coronary arteriogram.

Diagnostic peritoneal lavage in blunt abdominal trauma victims

Diagnostic peritoneal lavage (DPL) is an accepted method for evaluating patients with suspected intra-abdominal injury, especially in those with blunt abdominal trauma for whom early operative intervention may be life-saving. To evaluate this method in blunt abdominal trauma victims, we prospectively studied 2010 patients with blunt abdominal trauma who underwent DPL between 1978 and 1996 in our emergency department (at the regional tertiary university medical centre). The patients were then divided into three groups based on their DPL results. Of the total of 2010 patients, 719 (35.8%) met the criteria for positive DPL, indicating the need for laparotomy; 1213 (60.3%) had a negative DPL; and the remainder (78 patients, 3.9%) had equivocal DPL results. All the patients with positive DPL underwent emergency laparotomies which were therapeutic in 547 (76.1%) and non-therapeutic in 156 (21.7%) who had intra-abdominal haemorrhage. Sixteen patients out of 719 (2.2%) had no organ injuries in explorative laparotomy. When the 2010 cases in this study were evaluated, overall rates of specificity, sensitivity and positive predictive rates were found to be 87.3%, 96.3% and 76.1% respectively; the false positive rate was 23.9%, the false negative rate 1.8% and the negative predictive value 98.2%. Complications related to DPL developed in 31 patients (1.5%) out of the 2010 undergoing DPL. It is evident from the results that DPL is a reliable method. However, the criteria for positive DPL should be re-assessed based on the fact that the method itself had a false positivity rate of 23.9% leading to unnecessary operations.