Alterations of paraoxonase and platelet-activating factor acetylhydrolase activities in patients on peritoneal dialysis.

OBJECTIVE: The more atherogenic lipid profile seen in peritoneal dialysis (PD) patients cannot fully explain the increased incidence of atherosclerosis in this population. Oxidative modification of low-density lipoproteins (LDL) is considered to play a central role in the atherogenic process, whereas high-density lipoprotein (HDL) protects LDL from oxidation. On the other hand, it has been suggested that the LDL and HDL of PD patients are more resistant to oxidation than those of control subjects, while PD-HDL equally protects LDL from oxidation compared to control-HDL. Two HDL-associated enzymes have been shown to protect both LDL and HDL from oxidation: paraoxonase (PON1) and HDL-associated platelet-activating factor acetylhydrolase (HDL-PAF-AH). Furthermore, low PON1 activity and high total plasma PAF-AH concentration, which represents mainly the LDL-associated enzyme, have been shown to be independent risk factors for coronary artery events in the general population. However, there are limited data regarding possible alterations of these enzymes in PD patients. The aim of our study was to examine the possible alterations of PON1 and PAF-AH activities in patients undergoing PD. DESIGN: A cross-sectional study. SETTING: A university medical center. PARTICIPANTS: 56 PD patients of Caucasian origin and 86 matched controls were studied. MEASUREMENTS: In all subjects, serum PON1 activity toward paraoxon (paraoxonase) and phenylacetate (arylesterase), as well as total serum and HDL-PAF-AH activities were measured; PON1 genetic polymorphisms known to influence PON1 activity (Q192R and M55L) were determined. RESULTS: The PD patients exhibited significantly increased serum PON1 (paraoxonase) and PON1 (arylesterase) activities compared to controls, regardless of the PON1 polymorphisms or the levels of HDL cholesterol. Additionally, PD patients had significantly elevated activities of total serum PAF-AH and HDL-PAF-AH, independently of the levels of LDL or HDL cholesterol. The ratio of HDL-PAF-AH/ total PAF-AH, which has recently been suggested to be a potential marker of atherogenicity, was decreased in these patients compared to controls. Moreover, no difference in the prevalence of PON1 polymorphisms between PD patients and controls was found. CONCLUSION: The elevated activities of PON1 and HDL-PAF-AH could explain the increased resistance of PD-HDL to oxidation; the higher activity of total PAF-AH and the decreased HDL-PAF-AH/ total PAF-AH ratio could contribute to the increased incidence of atherosclerosis in these patients.     

The use of three different mesh materials in the treatment of abdominal wall defects

Abstract Abstract. Various prosthetic materials have been proposed for the repair of abdominal wall defects. These materials offer tension-free repair and significantly lower recurrence rate. Their respective properties are related to such complications as seroma, infection, fistula formation, intestinal adhesions and removal. We compared the final outcome in treating abdominal wall defects in 56 patients with three different prosthetic materials: conventional polypropylene in a preperitoneal location, expanded polytetrafluoroethylene mesh, and hydrophilic membrane coated polyester mesh in an intraperitoneal location. The hydrophilic coated polyester group exhibited the lowest complication rate and the polypropylene group the highest. Electronic Publication     

Magnetic resonance angiography compared to intra-arterial digital subtraction angiography in patients with subarachnoid haemorrhage

Summary In order to evaluate the sensitivity and specificity of magnetic resonance angiography (MRA) in spontaneous subarachnoid haemorrhage, 14 patients with recent haemorrhage verified by CT or lumbar puncture were investigated with both selective intra-arterial digital subtraction angiography (IA-DSA) and MRA by two independent teams, each having the same preangiographic information. The results were compared with each other and whenever possible (all positive cases except one) with those of surgical intervention. Seven patients were identified by MRA and IA-DSA as having a single aneurysm on the circle of Willis, 1 an aneurysm of the posterior inferior cerebellar artery 1 an aneurysm of the internal carotid artery (siphon) and 2 patients with two aneurysms on the circle of Willis. MRA and IA-DSA both failed to demonstrate aneurysms in 2 cases. Three patients had negative results on both methods and no surgical intervention was attempted. The aneurysms ranged from 0.3 to 1.5 cm in size. In most cases there was agreement between MRA and DSA, leading us to believe that, if the proper protocols are followed, MRA is a powerful alternative to other established methods in the detection of intracranial aneurysms. At this stage it will not replace IA-DSA prior to surgery, but the ability to obtain various projections using 3D MRA may improve surgical planning.     

Radiation Therapy Alone for Growth Hormone-Producing Pituitary Adenomas

We present our experience in the treatment of growth hormone (GH)-producing pituitary adenomas using irradiation alone. Between 1983 and 1991, 21 patients suffering from GH-secreting pituitary adenomas were treated with radiotherapy alone. Two bilateral opposing coaxial fields were used in 10 patients and in the remaining 11 a third frontovertex field was added. Treatment was given in 1.8-2 Gy daily fractions and total dose ranged between 45 and 54 Gy. Treatment was given using a cobalt unit. Four patients treated with somatostatin prior to and 14 patients treated after the end of radiotherapy experienced symptom relief for 6-28 weeks. The 5-year actuarial rate of disease control was 72%. Five out of six failed patients had macroadenomas. Hypopituitarism was observed in 5/21 (24%) patients. Whereas RT alone is effective in the treatment of microadenomas, this is not true for large infiltrative macroadenomas.     

Opioids modulate pituitary receptors for gonadotropin-releasing hormone

The number of pituitary GnRH receptors (GnRH-BC) is stable throughout the day in ovariectomized-estradiol treated rats, but undergo an acute transient reduction prior to the afternoon gonadotropin surge. To investigate the mechanisms controlling GnRH-BC we studied the effects of opioid-active compounds in this model. Morphine, given at 1400h, abolished both the LH surge and the preceding fall in GnRH-BC. Morphine given at 0900h increased GnRH-BC 30 min later, and this effect was abolished by simultaneous administration of naloxone. Naloxone alone produced an acute transient fall in GnRH-BC of similar magnitude to that seen before the spontaneous LH surge. These data suggest that alterations in endogenous opioid activity can modulate GnRH receptors and may form part of the mechanisms which initiate the afternoon gonadotropin surge.     

Design of removable partial dentures: a survey of dental laboratories in Greece

The aim of this study was to compare data on design and fabrication methods of removable partial dentures (RPDs) in two major cities in Greece. A questionnaire was sent to 150 randomly selected dental technicians. The participation rate was 79.3%. The anterior palatal strap, the lingual bar, and the Roach-type clasp arm designs were preferred. Half of the RPDs fabricated were retained using precision attachments. Differences between the two cities were observed in types of major maxillary connectors used, types of attachments and impression materials used, as well as the design of distal-extension RPDs. Postdoctoral education was found to have an impact on RPD fabrication. Despite the differences observed, design and fabrication of RPDs followed commonly used principles.     

Challenges in the treatment of angiosarcoma: a single institution experience

Background

Angiosarcomas are rare tumors that carry poor prognosis. Because of insidious growth rate, the diagnosis is often difficult and delayed.

Methods

Between 1990 and 2011, 72 (41 female, 31 male) patients were treated at our institution. Pathologic confirmation was obtained and multiple prognostic factors were evaluated for survival.

Results

Forty-four cases were sporadic and 28 cases were secondary. In the sporadic group, 16 (36%) patients had increased sun exposure, while in the secondary group, the majority (n = 23, 82%) of patients had prior exposure to radiation. The latent period between radiation exposure and diagnosis was predictive of survival (P = .037). Presentation was delayed by more than 3 months in 41% of patients. The majority of men developed head and neck angiosarcomas (n = 15, 48.5%), while women developed breast angiosarcomas (n = 21, 51%). Median survival was prolonged in patients treated initially with surgery.

Conclusions

A delay in the diagnosis of angiosarcoma can affect survival. Clinical suspicion and prompt diagnosis are essential for successful multimodal therapy. Initial surgical resection with adjuvant chemotherapy provides survival advantage.