Effects of Imatinib Mesylate on Renin–Angiotensin System (RAS) Activity during the Clinical Course of Chronic Myeloid Leukaemia

The renin–angiotensin system (RAS) is involved in cell growth, proliferation and differentiation in bone marrow in an autocrine–paracrine manner, and it modulates normal and neoplastic haematopoietic cell proliferation. This study aimed to assess expressions of the RAS components, renin, angiotensinogen and angiotensin-converting enzyme (ACE), during imatinib mesylate treatment of patients with chronic myeloid leukaemia (CML). Expressions of RAS components were studied in patients with CML at the time of diagnosis ( n = 83) and at 3, 6 and 12 months after diagnosis ( n = 35) by quantitative real-time polymerase chain reaction. De novo CML patients had increased ACE, angiotensinogen and renin mRNA levels and these expression levels decreased following administration of imatinib. The RAS activities were significantly different among Sokal risk groups of CML, highlighting the altered biological activity of RAS in neoplastic disorders. The results of this study confirm that haematopoietic RAS affects neoplastic cell production, which may be altered via administration of tyrosine kinase inhibitors such as imatinib mesylate.

5-Hydroxytryptamine-2A receptor gene (HTR 2 A) candidate polymorphism (T 102 C): Role for human platelet function under pharmacological challenge ex vivo

Although the environmental and life-style factors influencing individual predisposition to acute myocardial infarction (AMI) have been well documented, little is known on the identity of genetic loci that may contribute to risk for AMI. Recently, genetic studies in patients with nonfatal AMI have suggested an association with the T 102 C polymorphism in the serotonin 5-HT(2A) receptor gene (HTR 2 A). Considering the significant role of the 5-HT(2A) receptor in serotonin-induced platelet responses and the contribution of platelet (patho)physiology to thromboembolic events, we postulated that the increased susceptibility to AMI in patients with the T 102 homozygosity may be attributable, in part, to altered serotonin-mediated platelet function. In a group of healthy volunteers recruited from the Eskisehir region in central Turkey (N=37), we investigated the functional consequences of HTR 2 A T 102 C polymorphism in relation to platelet pharmacodynamics ex vivo. The platelet shape change and aggregation response to serotonin were measured with use of the platelet aggregometry and expressed as aggregometer output (mm). Because the circulating catecholamine hormone epinephrine can augment platelet aggregation, pharmacodynamic response (aggregation and its inhibition by 5-HT(2A) receptor antagonist cyproheptadine) was measured in the presence of both serotonin and epinephrine, to mimic the clinical situation in patients. The mean platelet aggregation was higher by 38% in subjects with T 10 2 homozygosity (T/T genotype, N=13) when compared with the carriers of the 102 C-allele (T/C and the C/C genotypic groups, N=24) (39.5 mm+/-12.3 vs. 28.7 mm+/-16.8, respectively) (mean+/-SD) (p<0.05). On the other hand, neither the serotonin-induced platelet shape change nor the cyproheptadine inhibition of platelet aggregation was influenced by the HTR 2 A T 102 C genetic variation (p>0.05). These findings in healthy subjects may provide a mechanistic explanation for the previously reported genetic association between HTR 2 A and AMI. Further genetic association studies of the 5-HT(2A) receptor in patients with AMI in different populations are warranted.

Is there an association of plasma homocysteine levels with vascular involvement in patients with Behçet's syndrome?

OBJECTIVE

To assess whether or not plasma homocysteine levels play a part in vascular involvement in Behçet's syndrome (BS).

METHODS

74 consecutive BS patients fulfilling the criteria of the International Study Group for BS, 35 healthy control (HC) and 14 rheumatoid arthritis (RA) patients on methotrexate (MTX) were studied. BS patients were then classified as those with and without vascular involvement. Fasting plasma homocysteine, folate, and vitamin B12 concentrations were measured by enzyme immunoassay and chemiluminescent immunoassay methods respectively.

RESULTS

Plasma homocysteine levels were found to be higher in the BS patients than in the healthy control (16.08 +/- 7.5 vs. 12.9 +/- 6.3 micromol/L, p < 0.03). The homocysteine levels in the RA group on MTX were higher compared with both the BS and HC groups (28.7 +/- 9.9; p < 0.0001). No remarkable difference pertaining to homocysteine levels was found between BS patients with or without thrombosis (p < 0.86). Hyperhomocysteinemia was also detected in 11 out of 22 (50%) of the patients with vascular involvement, which proved to be of no significant difference in comparison with those without vascular involvement (20/52, 38%; chi2 = 0.26, p > 0.05). Active BS smokers exhibited a higher concentration of homocysteine in contrast to non-smoker BS sufferers (20 +/- 8.4 vs 14.1 +/- 6.1 micromol/l; p < 0.004). Smoking was determined to have a positive correlation with vascular involvement (r = 0.26, p < 0.046), as well as with homocysteine levels (r = 0.31, p < 0.012) in BS. Upon logistic regression analysis, smoking was found to have a significant relationship with vascular involvement (odds ratio 3.12 [95% CI 2.02-4.22] p = 0.04). There was no significant difference between the study groups with respect to their B12 vitamin and folate levels. We were unable to make any correlation between homocysteine and vitamin B12 or folate in any of the groups (p > 0.05).

CONCLUSIONS

No association was found between homocysteine levels and vascular involvement in our BS patients. We determined that smoking seems to pose a risk for vascular involvement in BS patients.

Lymphadenitis caused by Scedosporium apiospermum in an immunocompetent patient

A case of lymphadenitis caused by Scedosporium apiospermum in a 25-year-old immunocompetent woman had been misdiagnosed as tuberculous lymphadenitis. Clinical response to itraconazole therapy was obtained in 6 months; to our knowledge, this is the first report of lymphadenitis caused by S. apiospermum in humans.

Case report. Rhodotorula rubra fungaemia due to use of indwelling venous catheters

Rhodotorula has been an infrequent cause of infection in humans but there have been some case reports about this systemic yeast infection. In this article, a Rhodotorula rubra fungaemia due to an indwelling catheter in a 23-year-old woman who had been diagnosed with non-Hodgkin's lymphoma grade IV B is described.

Lymphocyte subtypes in asthma: relationship with the clinical status and bronchial hyperreactivity

To study the role of T lymphocytes in asthma and its relationship with clinical severity, atopic status and bronchial hyperreactivity (BHR), we have examined T cell populations in peripheral blood of 32 stable asthmatic (18 non atopic, 14 atopic) and 10 non atopic-non asthmatic person using flow cytometry. BHR was determined with histamine challenge test. The percentages of CD4+, CD8+ T lymphocytes, CD4/CD8 ratios, T cell activation markers (IL-2R, CD25; HLA-DR) were not different from control (p > 0.05). The percentage of CD16+ CD56+ cells were higher in peripheral blood of asthmatics (15.5% versus 9.3% p < 0.05). In the asthmatic group, there was inverse correlation between BHR and CD4/CD8 ratio (p < 0.05). The percentages of CD5+ T lymphocytes bearing activation marker CD25 significantly higher in severely asthmatics when compared with mild asthmatics (13.2 +/- 2.0 versus 7.8 +/- 1.1% p < 0.05). These results suggest that natural killer activity is increased in the asthmatics, severely asthmatics have more T lymphocytes bearing activation marker CD25 and BHR would be related with CD4/CD8 ratio rather than the other T lymphocytes subpopulations in peripheral blood.

T lymphocyte activation in bronchoalveolar lavage of patients with interstitial lung disease

To study the role of T-lymphocytes in the patients with alveolitis due to interstitial lung disease (ILD), we have examined T cell populations in bronchoalveolar lavage (BAL) and peripheral blood (PB) of ten patients with ILD and six normal-controls via flow cytometry. The percentages of T-lymphocytes bearing the activation markers of HLA-DR (p < 0.01) and CD25 (p < 0.05) were significantly higher in BAL of ILD patients. There was no correlation between T lymphocytes subtypes and pulmonary functions and diffusion capacity (p > 0.05). In PB of ILD patients had less CD4+ T lymphocytes and CD19 cells (B lymphocytes) than controls (p < 0.05). This increased T-lymphocyte activation in BAL in contrast to PB suggested to have a role in the pathogenesis of the lung involvement in ILD.

Oxygen-free radicals impair fracture healing in rats

We studied the effect of oxygen-free radicals on fracture healing. 30 male rats were divided into 2 groups: 15 rats were given saline 5 mL/kg i.p. (control group) and 15 were given zymosan 100 mg/kg i.p. to induce oxygen-free radicals through stimulation of NADPH oxidase in polymorphonuclear leucocytes. 1 hour later, the right forelimbs of the rats were broken by light manual compression. These treatments were given once a day until the fifth post-fracture day. All rats were killed on day 22, and histological sections of the radius and ulna were examined without knowledge of the treatment given. The administration of zymosan impaired the fracture healing and therefore oxygen-free radicals appear to play an important role in fracture healing.