Anti-inflammatory effect of a novel locally acting A2A receptor agonist in a rat model of oxazolone-induced colitis.

Adenosine represents a powerful modulating factor, which has been shown to orchestrate the scope, duration, and remission of the inflammatory response through the activation of four specific receptors, classified as A1, A2A, A2B, and A3, all being widely expressed in a variety of immune cells. Several selective A2A receptor agonists have displayed anti-inflammatory effects, through the suppression of IL-12, TNF, and IFN-γ production by monocytes and lymphocytes, in the setting of chronic intestinal inflammation. However, the therapeutic application of A2A receptor agonists remains hindered by the risk of serious cardiovascular adverse effects arising from the wide systemic distribution of A2A receptors. The present study focused on evaluating the anti-inflammatory effects of the novel poorly absorbed A2A receptor agonist PSB-0777 in a rat model of oxazolone-induced colitis as well as to evaluate its cardiovascular adverse effects, paying particular attention to the onset of hypotension, one of the main adverse effects associated with the systemic pharmacological activation of A2A receptors. Colitis was associated with decreased body weight, an enhanced microscopic damage score and increased levels of colonic myeloperoxidase (MPO). PSB-0777, but not dexamethasone, improved body weight. PSB-0777 and dexamethasone ameliorated microscopic indexes of inflammation and reduced MPO levels. The beneficial effects of PSB-0777 on inflammatory parameters were prevented by the pharmacological blockade of A2A receptors. No adverse cardiovascular events were observed upon PSB-0777 administration. The novel A2A receptor agonist PSB-0777 could represent the base for the development of innovative pharmacological entities able to act in an event-specific and site-specific manner.

Role of the A(2B) receptor-adenosine deaminase complex in colonic dysmotility associated with bowel inflammation in rats.

BACKGROUND AND PURPOSE: Adenosine A(2B) receptors regulate several physiological enteric functions. However, their role in the pathophysiology of intestinal dysmotility associated with inflammation has not been elucidated. Hence, we investigated the expression of A2B receptors in rat colon and their role in the control of cholinergic motility in the presence of bowel inflammation. EXPERIMENTAL APPROACH: Colitis was induced by 2,4-dinitrobenzenesulfonic acid (DNBS). Colonic A(2B) receptor expression and localization were examined by RT-PCR and immunofluorescence. The interaction between A(2B) receptors and adenosine deaminase was assayed by immunoprecipitation. The role of A(2B) receptors in the control of colonic motility was examined in functional experiments on longitudinal muscle preparations (LMPs). KEY RESULTS: A(2B) receptor mRNA was present in colon from both normal and DNBS-treated rats but levels were increased in the latter. A(2B) receptors were predominantly located in the neuromuscular layer, but, in the presence of colitis, were increased mainly in longitudinal muscle. Functionally, the A(2B) receptor antagonist MRS 1754 enhanced both electrically-evoked and carbachol-induced cholinergic contractions in normal LMPs, but was less effective in inflamed tissues. The A(2B) receptor agonist NECA decreased colonic cholinergic motility, with increased efficacy in inflamed LMP. Immunoprecipitation and functional tests revealed a link between A(2B) receptors and adenosine deaminase, which colocalize in the neuromuscular compartment. CONCLUSIONS AND IMPLICATIONS: Under normal conditions, endogenous adenosine modulates colonic motility via A2B receptors located in the neuromuscular compartment. In the presence of colitis, this inhibitory control is impaired due to a link between A2B receptors and adenosine deaminase, which catabolizes adenosine, thus preventing A(2B) receptor activation.

Thalidomide plus monthly high-dose dexamethasone in chemorefractory myeloma. Results of a phase II clinical study.

Thalidomide is a potent anti-myeloma drug which can produce up to a 30-50% overall response rate (ORR) in pre-treated, chemorefractory multiple myeloma. Most authors agree with using 200 mg/daily with associated high dose dexamethasone (40 mg/daily x 4 days, 3 times monthly) considering lower doses investigational. We report our experience using thalidomide 100 mg/daily plus dexamethasone 40 mg/daily once a month, in 27 pre-treated patients. Thalidomide dose excalation and/or association with other drugs were established on the basis of the patient's response. Median age was 69 years (range 50-83 years) and 16 male and 11 female patients were treated. All patients had received more than 1 treatment line (range 1-5). Thalidomide was increased up to 300 mg/daily in 10 patients and 1 patient received up to 400 mg/daily. Two patients were not evaluable because of early death, 1 did not tolerate thalidomide because of pulmonary and neurological side-effects. Sixteen patients responded to this treatment, with an ORR of 66%. The combination of low-dose thalidomide plus monthly high-dose dexamethasone in chemorefractory myeloma showed interesting palliative results. According to our data, increasing thalidomide dosage and/or adding further drugs does not generally produce significant improvement.

Chemoresistant myeloma: phase II clinical study with low-dose thalidomide plus high-dose dexamethasone.

Thalidomide produces a response rate from 32 to 66% of pre-treated myeloma patients with doses ranging from 100 to 800 mg/daily. Common, dose-related side effects are sedation, constipation, polyneuropathy. Increased incidence of thromboembolic events were observed in myeloma patients receiving thalidomide as front-line therapy or in association with chemotherapy. Less common adverse reactions are central nervous system (CNS) dysfunction and cutaneous reactions. We describe the update of our experience with low dose thalidomide plus monthly high dose dexamethasone and zolendronate. Most patients were able to tolerate this regimen with few side effects. Erythrocyte sedimentation rate (ESR) lowering was early observed in patients who subsequently responded.

Low-dose thalidomide plus monthly high-dose oral dexamethasone (Thali-Dexa): results, prognostic factors and side effects in eight patients previously treated with multiple myeloma.

Thalidomide is active both as single agent and in combination-therapy against refractory or relapsing multiple myeloma. Eigth patients previously treated were given Thalidomide 100mg/daily plus Dexametasone 40mg/daily for four days each month (Thali-Dexa) and followed for response, prognostic factors and side effects. Two patients had early death (one from massive cerebral ischemic stroke, the other from dementia and progressive renal failure), one patient progressed during Thali-Dexa (thalidomide 200mg) and was rescued with chemotherapy, two patients required increasing thalidomide dosage (to 200 and 400mg, respectively) because of progressive disease, three patients had stable disease remission lasting from 4m+ to 16m+. Thali-Dexa is a useful agent but age and vascular/metabolic diseases may increase the risk of severe side effects. Early decrease in erythrocyte sedimentation rate seems to correlate with better disease control.

Thyroid metastases from colon cancer case report in a long term survivor.

Colon cancer usually has an hematogenous spread to liver and lung: rarely, or in the case of most advanced disease, also brain and bone can be involved. Thyroid metastasis is generally thought to be infrequent, breast and kidney cancer being the most frequent causes. Herein we present the case of a man affected by liver metastasis from colon cancer, who developed unusual metastasis to thyroid.

[Cancerous colonic polyps]. / Polipi cancerizzati del colon.

The treatment of cancerous polyps of the colon has not been definitely established. In the present study the authors have brought forth their contribution on the role played by endoscopic polypectomy alone or following a surgical resection. At our endoscopic service during the period from 1985 to 1992, there were 42 polyps diagnosed which after histologic examination showed an infiltrating carcinoma. 22 patients underwent surgery and 16 only an endoscopic polypectomy. The median follow-up was 43.3 months with a minimum period of 18 months. Four patients were lost during follow-up. We have analyzed for prognostic reasons, the type of polyps, the radicality of the polypectomy, the degree of differentiation and the infiltration of lymphatic and/or venous vessels of the polyp. The presence of carcinomal residue and lymphonodal metastases were taken into consideration in patients who underwent surgical resection. The results obtained were not evaluated statistically because of the limited number of patients with an adequately long follow-up. Nevertheless they are in line with those results from the majority of the cases quoted in other literature. In particular these cases which seem to have a favorable prognosis are those in which complete endoscopic polypectomy has coupled with a good degree of differentiation and the absence of infiltration of the lymphatic and venous vessels. In these cases surgery does not seem to have bettered the survival rate.

Low risk of transmission of the human immunodeficiency virus by a solvent-detergent-treated commercial factor VIII concentrate.

A study evaluating the risk of a commercial factor VIII (FVIII) concentrate's transmitting the human immunodeficiency virus (HIV) was carried out on hemophiliacs, by using multiple serological markers and the polymerase chain reaction (PCR). Twenty-nine hemophiliacs, negative for HIV antibodies, were treated for 18 months with a concentrate that had been inactivated by solvent-detergent. HIV-1 antibodies and antigen were assayed during the follow-up period. At the end of the study, all patients were also tested by the HIV 1 + 2 combined antibody assay; Western blot (WB) antibody analysis; and in eight cases, by an HIV-1 PCR technique. Patients received a yearly median FVIII dose of 35,330 IU (range 3,300-306,000); the median number of lots given to each patient was 6 (1-45). During the follow-up period and at the end of the study, HIV-1 antibodies and antigen were not detected in any of the subjects. The HIV 1 + 2 combined assay and WB analysis carried out only at the end of the study were negative. HIV-1 PCR was negative in all the tested patients. This study has shown that this solvent-detergent-treated FVIII concentrate did not transmit HIV.

Evaluation of factor VIII pharmacokinetics in hemophilia-A subjects undergoing surgery and description of a nomogram for dosing calculations.

The pharmacokinetics of factor VIII were studied in a series of 20 hemophilia-A patients undergoing surgery. Regardless of the type of operation, elimination of factor VIII was shown to be increased only in ten cases (50%) during the post-operative period. In this subgroup of patients, factor VIII half-life, measured immediately after surgery, was considerably shorter (mean = 9.6 hr, n = 10) than that determined in the same individual during the late operative period (mean = 17.8 hr, n = 10). These findings indicate that identification of patients with increased postoperative consumption of factor VIII can be of value in reducing the risk of hemorrhage in these subjects and in exposing other subjects with no postoperative increase in factor VIII clearance to less of the deficient factor. Data from 20 subjects were analyzed to construct a nomogram allowing individualized prediction of factor VIII dosing requirements. The nomogram, which is based on the "single point after a single dose" method, uses a value of factor VIII concentration measured at 10 hr after preoperative loading dose to predict the regimen producing the desired average steady-state concentration of factor VIII (30, 60, or 90 units/dl).

Multi-variate analysis of factors governing the pharmacokinetics of exogenous factor VIII in haemophiliacs.

The pharmacokinetics of Factor VIII was evaluated by mathematical modeling in a large-scale study in 62 haemophilia-A subjects, in whom 137 plasma Factor VIII-time curves were measured during single dose (n = 87) and repeated-dose (n = 47) treatments for prophylaxis or minor bleeding episodes. The pharmacokinetic parameters [mean (SD)] estimated from single-dose curves were: clearance 3.85 ml.h-1.kg-1, volume of distribution 58.2 ml.kg-1, mean residence time 15.9 h. Parameters calculated from repeated-dose curves were: clearance 3.93 ml.h-1.kg-1, volume of distribution 61.8 ml.kg-1, and half-life 12.2 h. In patients with mild haemophilia, pharmaco-statistical analysis revealed that the endogenous synthesis of Factor VIII was constant and was not influenced by the administration of exogenous Factor VIII. The coefficient of variation for intra-individual variability of Factor VIII kinetics (estimated according to the Standard Two-Stage method) was 20.7% in single-dose curves and 23.2% in repeated-dose curves.

Single-dose pharmacokinetics of factor IX evaluated by model-independent methods.

We studied the pharmacokinetic data of 13 subjects with hemophilia B treated with a single-dose of a Factor IX concentrate (Bebulin TIM2, N = 9; Preconativ, N = 4). The decay curves of Factor IX were evaluated by model-independent methods and the following pharmacokinetic parameters (mean +/- SD) were estimated: clearance (ml/h/kg) = 4.99 +/- 2.01; mean residence time (h) = 22.9 +/- 10.6; volume of distribution (ml/kg) = 99.9 +/- 35.5. The in vivo recovery (59.8% +/- 16.9%) was found to be inversely correlated with the volume of distribution. No significant difference in the pharmacokinetic parameters was found between patients treated with Preconativ and those treated with Bebulin. A model-dependent compartmental evaluation of the 13 decay curves showed that the two-compartment model was better than the one-compartment model in 7 cases (53.8%), but the improvement of fit resulting from the two-compartment model was statistically significant in only 2 cases (15.4%).