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Biomedical subjects

N Aras

Publications and source records attributed to N Aras.

At least 19 recordsLinked to original sources
PubMed2003

Retroperitoneal lipoblastoma involving the right common iliac artery and vein.

A case of benign lipoblastoma of the retroperitoneum in a 12-month-old boy, presenting as a huge abdominal mass and right lower extremity swelling, was reported. Surgery revealed involvement of the right common iliac artery and vein by lipoblastoma, requiring the sacrifice of both vessels for complete removal of the tumour. Vascular continuity of both vessels was re-established by a saphenous vein graft interposition. Involvement of a great artery by benign lipoblastoma has not been reported before.

Humans↗
PubMed2002

Comparison of long-term quality of life after laparoscopic and open cholecystectomy.

BACKGROUND: Although many studies have compared open and laparoscopic procedures, showing many advantages in favor of the laparoscopic technique during the early postoperative period, only a limited number of reports in the literature compare the two techniques during the later follow-up period with regard to quality of life. This study aimed to compare the effects of these two cholecystectomy techniques on the quality of life and clinical outcome of the patients during long-term follow-up evaluation. METHODS: This study evaluated 200 patients who underwent cholecystectomy operations with either technique between 1993 and 1999 in our department. There were 100 patients in each group. Both groups were similar with respect to age, gender, body mass indexes, American Society of Anesthesiology (ASA) scores, and indications for surgery. The Medical Outcome Study Short Form 36 Health survey (SF-36), which includes 36 items, was used for evaluating the quality-of-life index. In addition to this, a system-specific instrument for gastrointestinal diseases was used to investigate clinical outcome. RESULTS: The mean administration time for the questionnaire was 46.8 +/- 18.7 months in the laparoscopic cholecystectomy (LC) group and 41.5 +/- 16 months in the open cholecystectomy (OC) group. Statistically significant differences were noted in the scores for all eight SF = 36 health status domains in favor of laparospopic surgery. No statistically significant difference was found for abdominal pain, location of the pain, referral to a doctor for the pain, accompanying symptoms, relieving factors for the pain, distention, and dyspeptic complaints, usage of antacid therapy, weight changes, changes in bowel habit, need for a special diet, or sexual functions between the two groups. CONCLUSIONS: The gastrointestinal clinical symptoms were similar in the two groups during the long-term follow-up evaluation, but laparoscopic cholecystectomy was found to be significantly superior to the open technique with respect to the quality of life over the long term.

Abdominal Pain↗
PubMed2002

Contribution of calcium and other dietary components to global variations in bone mineral density in young adults.

A research project on comparative international studies of osteoporosis using isotope techniques was organized by the International Atomic Energy Agency (IAEA) with the participation of 12 countries (Brazil, Canada, Chile, China, Croatia, Hungary, Philippines, Russia, Singapore, South Africa, Turkey, and the United Kingdom). Participating centers in 11 countries (all but the UK) made measurements and collected data on men and women aged 15 to 49 years. In addition to studies of bone mineral density (BMD) at the femoral neck and lumbar spine using DEXA, anthropometric, lifestyle, and nutritional data were also collected. The results of the nutritional studies are reviewed in this paper. Overall, about 8% of the observed variability in spine BMD could be attributed to nutritional factors in men and women; in men, no such relationship could be determined. No single nutritional component (not even calcium) stood out as being of particular importance across all participating centers.

Absorptiometry, Photon↗
PubMed2001

Low-field interventional MRI in neurosurgery: finding the right dose of contrast medium.

MRI is increasingly being used as an interventional tool in neurosurgery. The field strength of "intraoperative" MR systems is usually lower than that of imagers commonly used for diagnostic purposes. However, lesion enhancement and apparent lesion extent depend on field strength. The aim of this study was to compare the contrast between intracranial, contrast-enhancing space-occupying lesions and the surrounding white matter obtained with low-field (0.2 T) and high-field (1.5 T) MR imaging and to find the contrast medium dosage for low-field MRI that produces the same lesion-to-white-matter contrast as the one obtained with high-field MRI after the administration of a standard dose of the contrast medium. A total of 38 patients with intracranial metastases or high-grade glioma were enrolled in this study. T1-weighted spin-echo sequences were acquired. High-field (1.5 T) studies were performed after the i.v. administration of 0.1 mmol gadolinium-DTPA/kg body weight. For low-field MRI (0.2 T) a dose escalation technique was used. T1-weighted sequences were repeated after each of three i. v. injections of 0.1 mmol gadolinium-DTPA/kg body weight. Thus, at the low-field examinations three T1-weighted sequences with a contrast medium dosage of 0.1, 0.2 and 0.3 mmol gadolinium-DTPA/kg body weight were obtained. Lesion-to-white-matter contrasts were calculated and compared. The average lesion-to-white-matter contrast obtained with high-field MR examinations was 1.63 (standard deviation 0.32). In the low-field MR examinations the average lesion-to-white-matter contrast was 1.34 (0.2) after a single dose, 1.57 (0.2) after a double dose, and 1.71 (.19) after a triple dose of contrast medium. The lesion-to-white-matter contrast of the high-field MR examination after a single dose of contrast medium was significantly higher than that of the low-field study after a single dose (P < 0.0001), but did not differ significantly from the low-field studies after a double (P = 0.28) or a triple dose (P = 0.17) of contrast medium. In a series of patients with contrast-enhancing space occupying brain lesions low-field MRI (0.2 T) after a double dose of contrast medium yielded the same lesion-to-white-matter contrasts as high-field MRI (1.5 T) after a standard dose. This is an important finding to avoid errors in intraoperative MRI due to the immanently lower degree of lesion enhancement in low-field MR imaging.

Adult↗
PubMed2001

Cavernosal arterial anatomic variations and its effect on penile hemodynamic status.

OBJECTIVE: With continuous improvements in ultrasound technology, small vessels with remarkably slow blood flow that may not be assessed by color Doppler ultrasonography, can be evaluated using power Doppler ultrasonography. In the present study, penile arterial anatomic variations were determined with power Doppler ultrasonography and its impact on penile hemodynamic status. METHODS: A total of 54 patients with erectile dysfunction were evaluated with power Doppler ultrasonography. The effects of vascular anatomic variations and the structure of the corpora cavernosa and tunica albuginea on vascular status were assessed on both sides. RESULTS: A normal penile vascular system was observed in 35.2% and 25% of 54 patients (mean age: 46.6+/-11.5 years) at the radix and mid-shaft of the penis, respectively. Pure arterial component was observed in 40.7% (22/54) and 47.2% (17/36) of the patients at the base and mid-shaft of the penis, respectively. Penile arterial insufficiency was severe in 9.2 and 5.5% of the patients at the base and mid-shaft of the penis, respectively, whereas intrapenile truncus was found in six patients (5.5%), the ratio of single cavernosal artery, intrapenile and extrapenile bifurcations were 69.4, 7.4 and 12.0%, respectively. Twenty (18.5%) dorso-cavernosal perforators, 15 (13.9%) cavernoso-dorsal and 30 (27.8%) intercavernosal branches were found. Peak systolic blood flow velocity values were decreased in 12 of 36 patients (33.3%) distally, while increased blood flow was observed in 11 (30.5%). CONCLUSIONS: Hemodynamic parameters might be variable at either side of the penis and depend on intrapenile arterial anatomic variations. Parameters determined using power Doppler ultrasonography should be evaluated from the proximal to distal side of the penis to obtain reliable and standard results. However, variations of penile arterial anatomy and its effect on penile hemodynamic changes should not be overlooked especially in the patients who are candidates for penile reconstructive or vascular surgery.

Adult↗
PubMed1999

Direct trocar insertion versus Veress needle insertion in laparoscopic cholecystectomy.

BACKGROUND: Direct insertion of the trocar is an alternative method to Veress needle insertion for the creation of pneumoperitoneum. The safety of direct disposable shielded trocar insertion for the creation of pneumoperitoneum was assessed by comparing with Veress needle insertion during laparoscopic cholecystectomy (LC). METHODS: One thousand five hundred patients undergoing LC with pneumoperitoneum were included in this study. In 470 patients the Veress needle insertion technique was used, and in 1,030 patients direct trocar insertion technique was used. Patients having indications for open trocar insertion were excluded from the study. RESULTS: Complication rate was significantly higher in the Veress needle group (14% versus 0.9%; P <0.01), and the two major complications, gastric perforation and iliac artery laceration, were also encountered in this group. CONCLUSIONS: Our results suggest that with a lower complication rate, direct insertion of the disposable trocar is a safe alternative to Veress needle insertion technique for the creation of pneumoperitoneum. Such an approach has further advantages such as less cost/instrumentation and rapid creation of pneumoperitoneum.

Adult↗
PubMed1999

The Kohonen network incorporating explicit statistics and its application to the travelling salesman problem.

In this paper we introduce a new self-organizing neural network, the Kohonen Network Incorporating Explicit Statistics (KNIES) that is based on Kohonen's Self-Organizing Map (SOM). The primary difference between the SOM and the KNIES is the fact that every iteration in the training phase includes two distinct modules-the attracting module and the dispersing module. As a result of the newly introduced dispersing module the neurons maintain the overall statistical properties of the data points. Thus, although in SOM the neurons individually find their places both statistically and topologically, in KNIES they collectively maintain their mean to be the mean of the data points, which they represent. Although the scheme as it is currently implemented maintains the mean as its invariant, the scheme can easily be generalized to maintain higher order central moments as invariants. The new scheme has been used to solve the Euclidean Travelling Salesman Problem (TSP). Experimental results for problems taken from TSPLIB [Reinelt, G. (1991). TSPLIB-A travelling salesman problem library. ORSA Journal on Computing, 3, pp. 376-384] indicate that it is a very accurate NN strategy for the TSP-probably the most accurate neural solutions available in the literature.

Journal Article↗
PubMed1999

Effect of hypertonic saline and alcohol on viability of daughter cysts in hepatic hydatid disease.

OBJECTIVE: To test the efficacy of hypertonic saline (20%) and absolute alcohol on the integrity of daughter cysts and the viability of the protoscoleces contained in these cysts. DESIGN: Experimental study. SETTING: Teaching hospital, Turkey. MATERIAL: 80 daughter cysts obtained from two patients with Gharbi type III hydatid cysts of the liver. INTERVENTIONS: The cysts were divided into two groups, in the first of which cysts were placed into hypertonic saline and in the second into absolute alcohol; they were kept there for 5, 15, 30 or 60 minutes. MAIN OUTCOME MEASURES: Integrity of the cyst wall and viability of the contents were evaluated using a vital staining technique with 0.1% eosin. RESULTS: Neither hypertonic saline nor absolute alcohol solution had any effect on the integrity of the daughter cysts or the viability of the protoscoleces. CONCLUSION: Percutaneous drainage of type III hydatid cysts can lead to high recurrence rates.

Cell Survival↗
PubMed1999

Surgically induced intracranial contrast enhancement: potential source of diagnostic error in intraoperative MR imaging.

BACKGROUND AND PURPOSE: Intraoperative MR imaging is being used increasingly during neurosurgical interventions. The aim of this study was to describe and classify different forms of surgically induced intracranial contrast enhancement observed during intraoperative MR examinations. METHODS: A total of 51 intraoperative MR examinations were performed to assess the extent of brain tumor removal. The intraoperative MR results (T1-weighted images, unenhanced and obtained serially after the IV administration of paramagnetic contrast material) were compared with preoperative and early postoperative MR findings. Animal experiments were conducted to obtain further evidence of the mechanism of surgically induced contrast enhancement. RESULTS: Four different types of surgically induced contrast enhancement were found: meningeal enhancement, increased enhancement of the choroid plexus, delayed enhancement at the resection margins, and immediate intraparenchymal contrast enhancement. The types of surgically induced contrast enhancement differ regarding their location, configuration, and time course. Their potential to be confused with contrast-enhancing, residual tumor also varies. Three of the four types of surgically induced contrast enhancement were reproducible in an animal model. CONCLUSION: Surgically induced contrast enhancement is a potential source of error in intraoperative MR imaging. Careful analysis of the location, configuration, and time course of intraoperatively observed intracranial enhancement is critical to avoid confusing surgically induced contrast enhancement with contrast-enhancing, residual tumor.

Animals↗
PubMed1999

Intraoperative MR imaging increases the extent of tumor resection in patients with high-grade gliomas.

BACKGROUND AND PURPOSE: MR is being used increasingly as an intraoperative imaging technique. The purpose of this study was to test the hypothesis that intraoperative MR imaging increases the extent of tumor resection, thus improving surgical results in patients with high-grade gliomas. METHODS: Thirty-eight patients with intracranial high-grade gliomas underwent 41 operations. Using a neuronavigation system, tumors were resected in all patients to the point at which the neurosurgeon would have terminated the operation because he thought that all enhancing tumor had been removed. Intraoperative MR imaging (0.2 T) was performed, and surgery, if necessary and feasible, was continued. All patients underwent early postoperative MR imaging (1.5 T). By comparing the proportions of patients in whom complete resection of all enhancing tumor was shown by intraoperative and early postoperative MR imaging, respectively, the impact of intraoperative MR imaging on surgery was determined. RESULTS: Intraoperative MR imaging showed residual enhancing tumor in 22 cases (53.7%). In 15 patients (36.6%), no residual tumor was seen, whereas the results of the remaining four intraoperative MR examinations (9.7%) were inconclusive. In 17 of the 22 cases in which residual tumor was seen, surgery was continued. Early postoperative MR imaging showed residual tumor in eight patients (19.5%) and no residual tumor in 31 cases (75.6%); findings were uncertain in two patients (4.9%). The difference in the proportion of "complete removals" was statistically highly significant (P = .0004). CONCLUSION: Intraoperative MR imaging significantly increases the rate of complete tumor removal. The rate of complete removal of all enhancing tumor parts was only 36.6% when neuronavigation alone was used, which suggests the benefits of intraoperative imaging.

Adult↗
PubMed1997

Ischemia and reperfusion injury: prevention of pulmonary hypertension and leukosequestration following lower limb ischemia.

Ischemia is a common clinical event with potentially serious consequences. The major part of tissue damage occurs upon reperfusion and is mediated by activated neutrophils. Ischemia reperfusion injury is manifested by oedema and increased microvascular permeability. This study tested cardiopulmonary functions following 2 h of lower limb ischemia. Anesthetized dogs were randomized into three groups: nonischemic sham dogs (n = 4), ischemic control dogs (n = 8) and ischemic dogs pretreated with prostaglandin (PG)E1 (n = 8). In control animals, mean pulmonary artery pressure (mPAP) increased 1 min after declamping from 13.37 +/- 2.61 mmHg to 16.88 +/- 3.68 mm Hg (P < 0.05). Pulmonary microvascular pressure (Pmv) increased within 1 minute of reperfusion from 7.71 +/- 1.87 mm Hg to 10.54 +/- 3.71 mm Hg (P < 0.05). These changes are consistent with increased lung microvascular permeability. White blood cell count fell slightly but not significantly and lung histology showed leukosequestration in alveoli of 171 +/- 22 polymorphonuclear leukocyte (PMN)/10 high powered fields (HPF) in the ischemic control group compared with 121 +/- 56 PMN/10 HPF in the sham group (P < 0.05). Systemic arterial pressure, cardiac output, central venous pressure and pulmonary artery wedge pressure were unaffected. In animals pretreated with PGE1, mPAP and Pmv were unchanged during reperfusion. Lung histologic findings appeared normal and leukosequestration was not observed. PMN counts in alveoli showed 95 +/- 26 PMN/10 HPF, lower than in ischemic control animals (P < 0.05). These data indicate that lower limb ischemia during reperfusion leads to pulmonary hypertension and leukosequestration, PGE1 infusion is effective in limiting ischemia reperfusion injury.

Alprostadil↗
PubMed1997

The fate of intraperitoneally retained gallstones with different morphologic and microbiologic characteristics: an experimental study.

Management of intraperitoneally retained gallstones after laparoscopic cholecystectomy (LC) is controversial, as their natural course is not known. This study was undertaken to assess the probable effects of stone morphology and clinically obvious infection on the outcome of retained gallstones in a mouse model. Forty albino mice were divided into four groups. Group I served as the control group (simple laparotomy, n = 10). Groups II, III, and IV (n = 10 in each group) were study groups. "Intact-sterile-cholesterol" (group II), "crushed-sterile-cholesterol" (group III), and "intact" (n = 5) [group IVa] and "crushed" (n = 5) [group IVb] "infected-cholesterol" gallstones aseptically retrieved from three different human patients were implanted to the peritoneal cavity of the animals. Group IV animals were implanted with stones retrieved from an acutely inflamed gallbladder with proven infection. Animals were sacrificed 6 and 12 weeks after the operations. Cultures and tissue samples were obtained. No animal was lost, no microscopic or macroscopic abnormality was observed in groups I and II, and cultures remained negative. In group III, adhesions surrounding the fragmented stones were evident at the 12th week, and no mortality was encountered. The histopathology revealed a fibroblastic reaction, and cultures remained negative in group III. In group IV, three animals from group IVb and one animal from group IVa died because of intra-abdominal sepsis before their sacrifice. All remaining mice showed severe adhesions with localized abscesses at the 12th week. In conclusion, intraperitoneally retained cholesterol gallstones remain inert and do not cause serious peritoneal reaction unless they are crushed into fragments or are from an acutely inflamed gallbladder. It is for this group of patients that laparotomy for total stone clearance is probably not justifiable. Better stone retrieval techniques or even laparotomy may be worthwhile considering in patients with crushed and particularly infected retained stones.

Animals↗
PubMed1997

Laparoscopic anterior extended seromyotomy with posterior truncal vagotomy: an experimental study.

We describe a new laparoscopic modification of parietal cell vagotomy. The laparoscopic anterior extended seromyotomy with posterior truncal vagotomy was performed in five pigs weighing 21 to 25 kg each. Congo-red and pH tests were undertaken 2 weeks later by open gastrotomy. The photographs of the stained gastric mucosa made at the 5-min interval after Congo-red administration were analyzed with a computer-driven area calculation program. Preoperative and postoperative weights were taken for all animals. The experimental parietal cell vagotomy group was compared with the sham group and showed a minimal amount of nondenervated parietal cell mass (0.9 +/- 0.4% versus 28.2 +/- 3.9%, p < 0.05). The pH values showed an inhibition of gastric acid secretion (7.8 +/- 0.7 versus 2.2 +/- 0.4, p < 0.05). During postoperative follow-up, no significant difference in the weight increase of the experimental and the sham control group was noticed (1.6 +/- 0.6 kg versus 2.0 +/- 0.1 kg, p < 0.27). The laparoscopic anterior extended seromyotomy with posterior truncal vagotomy efficiently suppresses gastric acid secretion, preserving the motility of the antrum and pylorus and diminishing the risk of residual areas of innervation. This procedure avoids dissection of the esophagus and can provide an easier but equally effective operative treatment of ulcer disease compared with other types of parietal cell vagotomy.

Animals↗
PubMed1997

Laparoscopic versus open cholecystectomy in cirrhotic patients: a prospective study.

The results of open cholecystectomy ([OC] n = 7) versus laparoscopic cholecystectomy ([LC] n = 7) in cirrhotic patients were analyzed prospectively. Groups were well matched for surgical indication, presence of ascites/bleeding tendency, and Child's grade. There was no mortality. Mean operating time was significantly longer in the LC group (155 +/- 47 vs. 103 +/- 25 min, p < 0.05). Operative blood loss was significantly greater in the OC group (128 +/- 125 vs. 642 +/- 467 ml, p < 0.05). No patient in LC group required blood transfusion in contrast to three patients in OC group. Compared with 0% postoperative complications in LC group, wound infections developed in 43% of the patients in OC group (p < 0.05). Mean hospital stay in LC group was significantly less (6.7 +/- 4 vs. 17.4 +/- 7.3 days, p < 0.01). Thus, contrary to previous belief, cirrhosis per se is not a contraindication to LC. Laparoscopic cholecystectomy may be the procedure of choice whenever cholecystectomy is indicated in a cirrhotic patient because it may be associated with less bleeding and fewer incision-related complications.

Blood Loss, Surgical↗
PubMed1997

Surgical treatment of hepatic hydatidosis combined with perioperative treatment with albendazole.

OBJECTIVE: To evaluate the effect of albendazole combined with surgery on the incidence of recurrent hydatid disease. DESIGN: Prospective open study. SETTING: Teaching hospital, Turkey. SUBJECTS: 25 patients who presented with hepatic hydatid disease between December 1992 and October 1995. INTERVENTIONS: Albendazole 10 mg/kg/day for a month before ultrasonography and then excision, and then albendazole for a further two months. RESULTS: 2 patients were excluded because the albendazole caused disturbance of liver enzyme activities. Of the remaining 23 patients only 7 had viable cysts on ultrasonography. In 15 patients (65%) the germinal layer was partially or totally destroyed, and in 15 the fluid was either cloudy or stained with bile. During a mean follow up period of 29 months only one patient developed recurrent disease. CONCLUSION: Perioperative treatment with albendazole resulted in fewer recurrences than expected. A longer preoperative period of treatment may increase the success rate; this requires further study.

Albendazole↗
PubMed1995

Haemodynamic effects of pneumoperitoneum during laparoscopic cholecystectomy: a prospective comparative study using bioimpedance cardiography.

The haemodynamic effects of increased intra-abdominal pressure during laparoscopic cholecystectomy in 22 patients were compared with those in 11 patients undergoing open cholecystectomy; bioimpedance cardiography was used for monitoring at predetermined time intervals. In the laparoscopy group stroke volume, cardiac and ejection velocity indices were significantly decreased and the total peripheral resistance index was significantly increased during the insufflation period when compared with preinsufflation and corresponding values in the group undergoing open operation. Routine intraoperative parameters such as heart rate and blood pressure did not show any significant change or indicate alterations in cardiovascular performance during laparoscopic procedures. Continuous non-invasive cardiovascular monitoring by bioimpedance cardiography may be useful in patients with limited cardiac function.

Adult↗