Transfusion of incompatible blood to a patient with alloanti-Sc1.

Sc1 is a high-prevalence blood group antigen that is part of the Scianna blood group system. The clinical significance of Scianna antibodies is not well understood because of their rarity; there are only a handful of cases in the literature. This scarcity of information can make it difficult to decide on the best course of action when transfusing a patient with alloantibodies to Scianna blood group antigens. We describe a case of an 85-year-old woman presenting with melena and a hemoglobin of 66 g/L. Upon request for crossmatched blood, a panreactive antibody was found, later elucidated to be alloanti-Sc1. Because of the urgent nature of the transfusion, the patient was transfused with 2 incompatible, presumed Sc1+, red blood cell units with no evidence of an acute or delayed transfusion reaction. This case has been shared with the International Society of Blood Transfusion Rare Donor Working Party, via their Outcome of Incompatible Transfusion form, and adds to the body of evidence on clinical significance of antibodies to the antigens of the Scianna blood group system.

Heregulin expression and prognosis in prostate adenocarcinoma.

BACKGROUND: Heregulins (HRG) are a family of growth factors acting as ligands to HER3, HER4 and HER family signalling. HRG has a concentration-dependent differential growth effect--low levels mitogenic, high levels inhibitory. HRG differentially affects hormone-naïve (inhibitory) and castrate-resistant (proliferative) prostate adenocarcinoma (CaP) cell lines. We postulate that differential HRG expression in CaP will be associated with alteration in tumour growth, development and prognosis. PATIENTS AND METHODS: HRG expression was assessed in 2 cohorts: cohort 1 of 45 patients with paired hormone-naïve and castrate-resistant samples, and cohort 2 of 357 hormone-naïve samples. Correlations between HRG expression and biochemical relapse and survival were determined. RESULTS: In cohort 1, hormone-naïve samples' high membranous HRG expression was associated with increased time to relapse (p = 0.036), time to death from relapse (p = 0.002) and overall survival (p = 0.001). Membrane HRG fell significantly in post-relapse specimens. In cohort 2, high membranous HRG was associated with increased time to relapse (p = 0.004) and overall survival (p = 0.044) in patients treated with castration therapy but only with overall survival (p = 0.002) in the full cohort. CONCLUSION: High HRG expression is associated with improved prognosis in hormone-naïve CaP and a fall in expression occurs at castration escape indicating a protective role against castrate resistance.

Is PTEN loss associated with clinical outcome measures in human prostate cancer?

Inactivating PTEN mutations are commonly found in prostate cancer, resulting in an increased activation of Akt. In this study, we investigate the role of PTEN deletion and protein expression in the development of hormone-refractory prostate cancer using matched hormone-sensitive and hormone-refractory tumours. Fluorescent in situ hybridisation and immunohistochemistry was carried out to investigate PTEN gene deletion and PTEN protein expression in the transition from hormone-sensitive to hormone-refractory prostate cancer utilising 68 matched hormone sensitive and hormone-refractory tumour pairs (one before and one after hormone relapse). Heterogeneous PTEN gene deletion was observed in 23% of hormone sensitive tumours. This increased significantly to 52% in hormone-refractory tumours (P=0.044). PTEN protein expression was observed in the membrane, cytoplasm and the nucleus. In hormone sensitive tumours, low levels of cytoplasmic PTEN was independently associated with shorter time to relapse compared to high levels of PTEN (P=0.028, hazard ratio 0.51 (95%CI 0.27-0.93). Loss of PTEN expression in the nucleus of hormone sensitive tumours was independently associated with disease-specific survival (P=0.031, hazard ratio 0.52, 95%CI 0.29-0.95). The results from this study demonstrate a role for both cytoplasmic and nuclear PTEN in progression of prostate cancer to the hormone-refractory state.

Mechanism of Phosphodiesterase 5 inhibitor relief of prostatitis symptoms.

BACKGROUND: Chronic prostatitis is a common urological complaint without clearly defined causation or definitive treatment. HYPOTHESIS: Phosphodiesterase 5 (PDE5) Inhibitor mediated relaxation of prostatic duct smooth muscle increases washout of prostatic reflux products reducing prostatic inflammation and consequent prostatitis symptoms. RATIONALE OF HYPOTHESIS: The presence of both Nitric Oxide Synthase and Phosphodiesterase 5 in human prostatic tissue and the effect of nitric oxide donors and PDE5 inhibitors in vitro indicate PDE5 inhibitors relax prostatic smooth muscle. Significant retrograde urinary flux into prostatic ducts has been described and suggested as the mechanism of chronic prostatitis. We postulate PDE5 inhibitors alter prostatic reflux hence prostatitis symptoms. CONCLUSION: PDE5 inhibitors may represent a simple, effective treatment for chronic prostatitis.

Depression in patients with HIV infection.

The epidemiology, clinical features, and drug treatment of depression in HIV-infected patients are discussed. The lifetime prevalence of depression in patients infected with HIV has been estimated at 22-45%. The signs and symptoms of depression are similar in HIV-infected and noninfected patients, but patients with HIV infection may more frequently have sleep and appetite disturbances. Diagnosis should focus on affective or cognitive depression symptoms that reflect mood state alone. Patients with a history of depression, homosexual men, women, and i.v. drug abusers are among HIV-infected individuals who may be at increased risk for depression. Depression may alter the course of HIV infection by impairing immune function or influencing behavior. Depression my contribute to nonadherence to therapy. Antidepressant therapy is effective in most HIV-positive patients with major depression. Tricyclic antidepressants (TCAs) have produced response rates as high as 89%, but their usefulness has been limited by adverse effects. Selective serotonin-reuptake inhibitors and other non-TCAs have also demonstrated efficacy and are generally better tolerated. Psychostimulants have improved mood, cognition, and energy level, and androgens have been used for their anabolic effects. The systemic concentrations of antidepressants may be altered by coadministered drugs that affect their cytochrome P-450 isoenzyme-mediated metabolism; in turn, the metabolism and toxicity of certain antiretrovirals may be affected by antidepressants. Guidelines on the treatment of depression in the general population may be applied to patients with HIV infection. Depressive disorders are prevalent among patients with HIV infection but often respond to a variety of treatments.

Pharmacokinetics and pharmacodynamics of clozapine.

The introduction of clozapine has given clinicians a unique agent for treating patients with schizophrenia that is refractory to other neuroleptics. Despite its efficacy, the drug continues to be prescribed with trepidation due to the incidence of agranulocytosis. This article reviews the pharmacokinetic and pharmacological properties of clozapine and the clinical implications for monitoring plasma concentrations. Various assays have been developed for clozapine that include gas-liquid chromatography, radioimmunoassay and high performance liquid chromatography. Only a few studies have examined the pharmacokinetics of clozapine in patients with schizophrenia. These studies have revealed a wide interpatient variability in pharmacokinetic parameters that include: time to reach peak plasma concentrations 1.1 to 3.6h; elimination half-life 9.1 to 17.4h; clearance 8.7 to 53.3 L/h; and a volume of distribution of 1.6 to 7.3 L/kg. Clozapine is metabolised via the hepatic microsomal enzyme system into 2 principle metabolites: demethyl-clozapine and clozapine N-oxide. Urine samples have reported the ratio of clozapine:demethyl:N-oxide to be 1:1:2. The clozapine N-oxide binding affinity with 3H-haloperidol was 4 times lower than clozapine and its conversion back to clozapine is hypothesised. Although the exact pharmacological mechanism of action of clozapine is not fully understood, the drug does possess significant binding affinity for different dopamine receptors, with recent evidence supporting binding to the D4 receptor subtype. Clozapine transiently increases serum prolactin levels with minimal changes in homovanillic acid plasma levels. Limited studies investigating the relationship between clinical response and plasma clozapine concentrations have investigated the range between 100 and 800 micrograms/L. In the treatment of patients with refractory schizophrenia, a minimum concentration of 350 micrograms/L was suggested as needed. The occurrence of agranulocytosis could have a genetic basis and patients should be rigorously monitored during treatment. The incidence of tardive dyskinesia and extrapyramidal side effects is minimal. Clozapine can lower the seizure threshold in a dose- and time-dependent manner. Careful patient selection and monitoring are required when clozapine therapy is used in patients with schizophrenia.

Paroxetine, sertraline, and fluvoxamine: new selective serotonin reuptake inhibitors.

The pharmacology and pharmacokinetics, adverse effects, drug interactions, efficacy, and dosage and administration of the new selective serotonin reuptake inhibitors paroxetine, sertraline, and fluvoxamine are reviewed. Paroxetine, sertraline, and fluvoxamine all have large volumes of distribution and are highly bound to plasma proteins. In contrast to fluoxetine, these three drugs possess shorter elimination half-lives of approximately one day and are metabolized to clinically inactive compounds. Nausea was the most commonly reported adverse effect for all three agents. Other reported adverse effects are headache, sedation, dry mouth, insomnia, sexual dysfunction, and constipation. Because of their favorable pharmacokinetic profiles, paroxetine, sertraline, and fluvoxaetine are less likely than fluoxamine to interact with other drugs. Paroxetine has been found to be superior to placebo and equivalent to amitriptyline, imipramine, clomipramine, and doxepin in treatment of depression. Sertraline has been found to be superior to placebo and equivalent to amitriptyline in treatment of depression. Fluvoxamine has been found to be superior to placebo and equivalent to imipramine, clomipramine, desipramine, mianserin, and maprotiline in the treatment of depression. Fluvoxamine and sertraline have been shown to be superior to placebo in the treatment of obsessive-compulsive disorder. Clinical experience has demonstrated all three drugs to be effective in treatment of depression. They may be especially useful in elderly patients, in those who cannot tolerate alternative treatments, and in those who do not respond to adequate trials of other antidepressant therapies.

Increased carbamazepine plasma concentrations after fluoxetine coadministration.

The interaction between fluoxetine and carbamazepine was investigated in six normal, healthy male volunteers (aged 23 to 40 years). Subjects were given carbamazepine, 400 mg every morning, for 3 weeks. Venous carbamazepine blood samples were obtained at baseline and 1, 2, 4, 6, 8, 10, 12, and 24 hours after the morning dose. Fluoxetine, 20 mg every morning, was then coadministered with carbamazepine for 7 days. Venous carbamazepine blood samples were again obtained as described. Carbamazepine and carbamazepine-10,11-epoxide (CBZE) were assayed by HPLC. Addition of fluoxetine resulted in a significant increase in the area under the concentration-time curve of carbamazepine (105.93 +/- 18.05 micrograms/ml.hr versus 134.97 +/- 12.15 micrograms/ml.hr; t = 3.284; df = 5; p = 0.022) and CBZE (11.6 +/- 1.93 micrograms/ml.hr versus 15.2 +/- 2.4 micrograms/ml.hr; t = 2.805; df = 5; p = 0.038). Both oral and intrinsic clearance of carbamazepine was decreased significantly on fluoxetine addition (3.87 +/- 0.68 L/hr versus 2.98 +/- 0.26 L/hr; t = 3.025; df = 5; p = 0.029 and 17.90 +/- 4.9 L/hr versus 11.92 +/- 1.4 L/hr; t = 3.037; df = 5; p = 0.029, respectively). No significant changes were determined for fraction of absorbed dose, volume of distribution, absorption rate constant, and elimination rate constant. These findings suggest that fluoxetine can inhibit the metabolism of carbamazepine. Careful monitoring of patients is recommended when these two drugs are coadministered.