Phorbol 12-myristate 13-acetate induces beta-adrenergic receptor uncoupling and non-specific desensitization of adenylate cyclase in human mononuclear leukocytes

Tumour-promoting phorbol esters such as phorbol 12-myristate 13-acetate (PMA) have been reported to modulate beta-adrenergic receptor responses in various cell types, presumably by the activation of protein kinase C. In the present investigation we assessed the effect of PMA on the beta-adrenergic receptor-adenylate cyclase system of human mononuclear leukocytes (MNL). It was found that incubation of MNL with PMA resulted in a time- and concentration-dependent desensitization of isoproterenol-induced adenylate cyclase activity. However, the effect of PMA was not restricted to the beta-adrenergic receptor system, since basal adenylate cyclase activity and histamine-, prostaglandin E1-, 5'-guanylylimidodiphosphate (GppNHp)-, and NaF-stimulated values were also reduced. By contrast, no effect was found on the forskolin-induced adenylate cyclase activity. The inactive phorbol ester, 4 alpha-phorbol 12,13-didecanoate had no effect on adenylate cyclase at all, suggesting that the observed PMA effect was specifically mediated by activation of protein kinase C. The reduced beta-adrenergic response induced by PMA was not associated with a reduced beta-adrenergic receptor number, indicating uncoupling of this receptor from adenylate cyclase. Isoproterenol competition curves for 3H-dihydroalprenolol binding to membranes from untreated and PMA-treated cells demonstrated that the uncoupling was due to a reduced ability of the agonist to promote formation of the guanine nucleotide-sensitive high affinity state of the receptor. The results indicate that PMA may cause desensitization of catecholamine-responsive adenylate cyclase in MNL, and that the major locus of alteration is the guanine nucleotide regulatory protein.     

Continuous infusion of low-dose doxorubicin, epirubicin and mitoxantrone in cancer chemotherapy: A review

With the recent development of reliable portable pumps and safe venous access systems, continuous infusion of chemotherapeutic agents on an out-patient basis has become feasible. Advantages of continuous infusion are the long-term exposure of tumour cells to the drug and the fact that most toxic effects are reduced for doxorubicin, epirubicin and mitoxantrone due to elimination of the high peak plasma levels. Preliminary data for doxorubicin suggest that its antitumour activity is maintained. Pharmacokinetic studies with epirubicin and mitoxantrone showed a linear relationship between drug dose infused and the steady-state plasma level for these drugs. The area under the curve for leukocytes drug level was higher during continuous infusion than after an equitoxic bolus injection of epirubicin and mitoxantrone. Well-randomized clinical trials will be necessary to investigate the role of continuous infusion of antracyclines and mitoxantrone in cancer chemotherapy in the future.     

Puberty Suppression in Adolescents With Gender Identity Disorder: A Prospective Follow‐Up Study

IntroductionPuberty suppression by means of gonadotropin‐releasing hormone analogues (GnRHa) is used for young transsexuals between 12 and 16 years of age. The purpose of this intervention is to relieve the suffering caused by the development of secondary sex characteristics and to provide time to make a balanced decision regarding actual gender reassignment.AimTo compare psychological functioning and gender dysphoria before and after puberty suppression in gender dysphoric adolescents.MethodsOf the first 70 eligible candidates who received puberty suppression between 2000 and 2008, psychological functioning and gender dysphoria were assessed twice: at T0, when attending the gender identity clinic, before the start of GnRHa; and at T1, shortly before the start of cross‐sex hormone treatment.Main Outcome MeasuresBehavioral and emotional problems (Child Behavior Checklist and the Youth‐Self Report), depressive symptoms (Beck Depression Inventory), anxiety and anger (the Spielberger Trait Anxiety and Anger Scales), general functioning (the clinician's rated Children's Global Assessment Scale), gender dysphoria (the Utrecht Gender Dysphoria Scale), and body satisfaction (the Body Image Scale) were assessed.ResultsBehavioral and emotional problems and depressive symptoms decreased, while general functioning improved significantly during puberty suppression. Feelings of anxiety and anger did not change between T0 and T1. While changes over time were equal for both sexes, compared with natal males, natal females were older when they started puberty suppression and showed more problem behavior at both T0 and T1. Gender dysphoria and body satisfaction did not change between T0 and T1. No adolescent withdrew from puberty suppression, and all started cross‐sex hormone treatment, the first step of actual gender reassignment.ConclusionPuberty suppression may be considered a valuable contribution in the clinical management of gender dysphoria in adolescents. de Vries ALC, Steensma TD, Doreleijers TAH, and Cohen‐Kettenis PT. Puberty suppression in adolescents with gender identity disorder: A prospective follow‐up study. J Sex Med 2011;8:2276–2283.     

Inflammatory bowel disease in primary immunodeficiency disorders is a heterogeneous clinical entity requiring an individualized treatment strategy: A systematic review

ObjectiveTo describe the prevalence, clinical presentation and current treatment regimens of inflammatory bowel disease (IBD) in patients with primary immunodeficiency disorders (PIDs).MethodsA systematic review was conducted. The following databases were searched: MEDLINE, Embase, Web of Science, the Cochrane Library and Google Scholar.ResultsA total of 838 articles were identified, of which 36 were included in this review. The prevalence of IBD in PIDs ranges between 3.4% and 61.2%, depending on the underlying PID. Diarrhea and abdominal pain were reported in 64.3% and 52.4% of the patients, respectively. Colon ulceration was the most frequent finding on endoscopic evaluation, while cryptitis, granulomas, ulcerations and neutrophilic/lymphocytic infiltrates were the most frequently reported histopathological abnormalities. Described treatment regimens included oral corticosteroids and other oral immunosuppressive agents, including mesalazine, azathioprine and cyclosporin, leading to clinical improvement in the majority of patients. In case of treatment failure, biological therapies including TNF- α blocking agents, are considered.ConclusionsThe overall prevalence of IBD in patients with PID is high, but varies between different PIDs. Physicians should be aware of these complications and focus on characteristic symptoms to reduce diagnostic delay and delay in initiation of treatment. Treatment of IBD in PIDs depends on severity of symptoms and may differ between various PIDs based on distinct underlying pathogenesis. An individualized diagnostic and therapeutic approach is therefore warranted.     

Aplastic kidneys: Case report

In favor of the diagnosis of a functionless tuberculous kidney on the left were: (i) the history of previous pulmonary tuberculosis; (2) absence of function from the left kidney; (3) calcified areas in the left kidney region.Against the diagnosis of tuberculosis were: (1) the absence of urinary symptoms; (2) the normal bladder mucosa; (3) failure to find tubercle organism in the urine.In favor of aplasia of the kidney were: (1) the presence of a bicornuate uterus; (2) absence of the left ureteral orifice and smooth deformity of the left side of the bladder; (3) absence of function from the left kidney. The diagnosis of aplasia was made and confirmed by operation and pathologic examination.Injection of air into the renal fossa was used as an additional aid in diagnosis. This procedure carries with it the danger of air embolism and is open to criticism on that ground.The patient has experienced no pain since operation. It is difficult to explain this happy circumstance by nephrectomy. It is also too early after operation to be sure that the pain will not recur. In the meanwhile we have dilated the right ureter.