Leptin measurement in urine is a reliable method of monitoring its secretion in patients with obstructive sleep apnea syndrome.

Leptin is believed to play a significant role in the pathogenesis of obstructive sleep apnea syndrome (OSAS) as well as progression of OSAS-related obesity. It is also known that other factors such as gender and diurnal variations in serum strongly affect the measurement results making repeated blood sampling necessary for leptin precise monitoring. Since renal metabolism and urine secretion are the main elimination mechanism for leptin, in this study we evaluated urine relevance for leptin secretion monitoring. Serum and urine (collected during the day and overnight) sampled from 169 OSAS patients and 41 controls were assayed by immunoenzymatic method specific for human leptin. Only 5 (17%) controls and 10 (5.8%) OSAS patients had undetectable urine leptin. We observed significant relationships between serum and urinary leptin in both day-time (r=0.656, P<0.001) and night-time (r=0.518, P<0.001) samples and between day and night-time urine leptin (r=0.811, P<0.001). Significance values did not alter when urinary leptin levels were expressed as the ratio to urinary creatinine. Gender-related differences in leptin concentrations were present both in serum (P<0.001) and overnight urine (P<0.01) in the OSAS group. However, mean night-time urine leptin was lower in the OSAS patients (P<0.05) and their subgroups stratified according to disease severity (P<0.01), while serum leptin levels were comparable in both groups. We conclude that assaying leptin in urine by immunoenzymatic method is a reliable and useful non-invasive alternative for its serum measurement. However, night-time urine leptin levels better reflect differences in its turnover due to gender and OSAS severity.

Angiotensin-converting enzyme activity and angiomodulatory effects of sera in patients with diabetic retinopathy.

Aberrant neovascularization plays a crucial role in ocular complications in diabetic patients. Sera from these patients contain high levels of angiostimulatory factors, the most important of which is vascular endothelial growth factor (VEGF). Many authors have described elevation of angiotensin-converting enzyme (ACE) activity in the sera of diabetic patients. It is important to determine the possible relationship between these two phenomena. We studied ACE serum activity and VEGF concentrations in patients with type 1 and type 2 diabetes and retinopathy We also investigated the effect of their sera on cutaneous angiogenesis induced in mice by grafting healthy human mononuclear blood leukocytes. We found a negative correlation between the angiostimulatory effect and ACE level in the sera of patients with type 1 diabetes and no correlation between these two parameters in patients with type 2 diabetes. VEGF concentrations were lower and ACE activity was significantly higher in the sera of patients with type 1 diabetes than in the sera of those with type 2 diabetes.

Prostaglandins /PGs/ and peristalsis.

The effect of some inhibitors of PG-synthesis /Aspirin, Indomethacin and Suprofen/ on the small intestine peristalsis and the PG-like activity in mice was investigated. It was found that the three drugs examined in the applied doses did not affect the small intestine peristalsis but they significantly decreased the PG-like activity. The role of PGs in the physiological peristalsis of the small intestine is discussed.

A prostaglandin-like activity in small intestine and postirradiation gastrointestional syndrome.

A correlation between the postirradiation increase of the small intestine motility and the prostaglandin-like activity in this organ during gastrointestional syndrome was observed. Indomethacin decreased the elevated motility of intestine and reduced the prostaglandin-like activity in this syndrome.

Antithrombotic properties of dermatan sulphate in a rat venous thrombosis model.

It has been suggested that glycosaminoglycans (GAG) such as heparan sulphate (HS), dermatan sulphate (DS), chondroitin-4-sulphate and chondroitin-6-sulphate contribute to the nonthrombogenic properties of the vascular wall. We have investigated the potential role of DS and HS as antithrombotic agents in an experimental model of stasis-induced venous thrombosis in rats. We utilized a range of doses of both DS and HS (0.25-4 mg/kg BW) to test both their antithrombotic activity and potential bleeding effects. The results were evaluated with reference to an unfractionated heparin (0.5-2 mg/kg BW). We report that the antithrombotic activity of DS is not related to its anticoagulant activity as measured by the activated partial thromboplastin time (APTT), thrombin time (TT) and anti-Xa tests. The dose of DS which was able to inhibit thrombus formation by 70% did not prolong the bleeding time measured using two techniques (template and tail transection); in contrast, with HS a prolongation of both times could clearly be seen. On the other hand, standard unfractionated heparin, at a dose which is equipotent to that of DS in preventing thrombus formation, significantly prolonged the bleeding time. These results suggest that DS may be a useful antithrombotic agent with a lower haemorrhagic effect than heparin, unlike HS which expresses a haemorrhagic risk similar to heparin.

Impairment of primary haemostasis by low molecular weight heparins in rats.

Different low molecular weight (LMW) heparins were tested on primary haemostasis in rats. Four preparations were studied; one was devoid of any effect on the bleeding time, while the other three prolonged the bleeding time to varying extents. As a consequence we studied the effect of these heparins on platelet aggregation. The fractions which prolonged the bleeding time, also inhibited the ex vivo and in vitro platelet aggregation, whereas the one devoid of any effect on the bleeding time did not affect platelet aggregation. Similar results were obtained using both platelet-rich plasma (PRP) and gel-filtered platelets. The in vitro response of platelets to aggregating agents may offer a parameter to detect the presence of 'bleeding factor(s)' in some LMW heparin preparations.

[Usefulness of measuring levels of d-dimer for diagnosis of hospital venous thromboembolism]. / Przydatnosc oznaczania stezenia d-dimeru w diagnostyce szpitalnej zylnej choroby zakrzepowo-zatorowej (z.ch.z.z.).

D-dimer measurement with highly sensitive tests seems useful to rule out pulmonary embolism (PE) and deep vein thrombosis (DVT). However, nonspecific increase in d-dimer is common among inpatients. The aim of our study was to check: 1) whether the frequency of normal DD level in inpatients justifies its assessment as a part of diagnostic strategy for VTE, 2) whether tests that we are using are sensitive enough to exclude PE and DVT. In 27 (47%) out of 58 hospitalised patients evaluated by ultrafast ELISA (VIDAS bioMerieux), but in none of 20/58 patients with confirmed VTE, DD-level was found normal. In 35 of those patients DD was measured also with microlatex tests--Tinaquant and BC d-dimer. In 14/35 patients imaging test confirmed VTE. Sensitivity, specificity and negative predictive value (NPV) respectively were following: VIDAS: 100%, 80%, 100%, Tinaquant: 100%, 48%, 100%, BC d-dimer: 29%, 90%, 70%. Our results suggest that: 1) the relatively high frequency of normal DD-level among inpatients justifies its use in diagnostic strategies involving hospitalised patients, 2) negative VIDAS test confirms its as reliability for excluding VTE while 3) high sensitivity found for Tinaquant test encourages further prospective studies, 4) sensitivity of BC d-dimer is too low to be useful for excluding VTE.