Prolactin-releasing peptide and its homolog RFRP-1 act in hypothalamus but not in anterior pituitary gland to stimulate stress hormone secretion

The RF-amide peptides (RFRPs), including prolactin (PRL)-releasing peptide-31 (PrRP-31) and RFRP-1, have been reported to stimulate stress hormone secretion by either direct pituitary or indirect hypothalamic actions. We examined the possible direct effects of these peptides on PRL and adrenocorticotropin (adrenocorticotropic hormone [ACTH]) release from dispersed anterior pituitary cells in culture and on PRL and ACTH secretion following intracerebroventricular (icv) administration in vivo. Neither peptide significantly altered PRL or ACTH release from cultured pituitary cells (male rat donors). Central administration of 1.0 and 3.0 nmol of PrRP-31, but only the higher dose of RFRP-1, significantly elevated serum corticosterone levels in conscious male rats. The effect of PrRP-31 was not blocked by pretreatment (iv) with the corticotropin-releasing hormone (CRH) antagonist, α-helical CRH 9–41; however, pretreatment of the animals (iv) with an antiserum to CRH significantly lowered the hypothalamic-pituitary-adrenal axis response to central administration of PrRP-31. On the other hand, the release of PRL was significantly elevated by 3.0 nmol of RFRP-1, but not PrRP-31, in similarly treated, conscious male rats. Pretreatment with the catecholamine synthesis inhibitor, α-methyl-para-tyrosine, prevented the stimulation of PRL secretion observed following central administration of RFRP-1. RFRP-1 similarly did not alter PRL secretion in rats pretreated with the dopamine, D₂ receptor blocker, domperidone. These results suggest that the RF-amide peptides are not true neuroendocrine regulators of stress hormone secretion in the rat but, instead, act centrally to alter the release of neuroendocrine factors that do act in the pituitary gland to control PRL and ACTH release. In the case of RFRP-1, stimulation of PRL secretion is potentially owing to an action of the peptide to inhibit dopamine release into the median eminence. The corticosterone secretion observed following central administration of PrRP-31 does not appear, based on our current results, to be solely owing to an action of the peptide on CRH-producing neurons but, instead, may be a result of the ability of PrRP-31 to increase as well the exposure of the corticotrophs in vivo to other ACTH secretagogues, such as oxytocin or vasopressin.     

Fibrinolytic changes in pregnant women on highly active antiretroviral therapy

Objectives:

To report on the changes in fibrinolytic activity in human immunodeficiency virus (HIV) infected pregnant women who are undergoing highly active antiretroviral therapy (HAART).

Methods:

Blood was collected from 50 HIV positive women on HAART (test subjects), and 50 HIV positive women not on HAART (controls). These women were attending the prevention of mother to child clinic (PMTCT) of the University of Benin Teaching Hospital, Benin City, Nigeria from January to June 2014. Standard manual techniques were used to estimate plasma fibrinogen concentration (PFC), euglobulin lysis time (ELT), packed cell volume (PCV), and plasma viscosity (PV).

Results:

The mean ± standard error of mean (SEM) of PFC was 4.02±0.13g/l and ELT from the test subjects was 378±15 mins was significantly higher (p<0.05) compared with the control subjects (PFC 3.46±0.12g/l and ELT 267±9.0mins). The PCV or hematocrit values in the test subject was 29.1±0.38%, which was significantly lower (p<0.05) compared with the control subject (31.3±0.43%). The PV in the test subject was 1.76±0.02 mPa/s, while the control subjects was higher (1.73±0.02 mPa/s). This increase was not statistically significant (p>0.05). There were differences in the various parameters investigated when the various trimesters were compared. These differences did not, however, follow a particular pattern.

Conclusion:

Highly active antiretroviral therapy can cause changes in fibrinolytic activity that may predispose pregnant women to hyperfibrinogenemia and anemia.During pregnancy the physiology of a woman is temporary changed to accommodate the newly developing fetus.1 Conception occurs during ovulation, which is approximately on the fourteenth day of a regular menstrual cycle. In conception, the ovum is fertilized in the fallopian tube and becomes a zygote, which is then carried into the uterus. There are changes in the coagulation and fibrinolytic system during pregnancy and knowledge of these physiological changes characterized by hemodilution, changes in the concentration of one or more plasma protein fractions, and reduced fibrinolytic activity is necessary to manage 2 of the more serious problems in pregnancy; namely hemorrhage and thrombo-embolic diseases.2 Increased levels of plasma proteins and reduced fibrinolytic activity have been reported in pregnancy,3 while prolonged euglobulin lysis time (ELT) and increased levels of fibrinogen have also been observed in pregnancy.4 While numerous studies have examined optimal methods for prevention of mother to child transmission of human immunodeficiency virus (HIV) and subsequent response to HAART,5 as well as the impact of pregnancy on outcomes of HIV in the pre-HAART era,6 little is known of the impact of pregnancy on response to HAART in Africa. There are several biologically plausible mechanisms that might alter efficacy of several antiretroviral agents including changes in enzyme activity and beta-estradiol levels, pregnancy-related changes in blood volume and body mass index, and factors which may compromise adherence to HAART ante and post-partum, such as nausea/vomiting, labor-associated morbidity, or responsibility for a new infant.7 Human immunodeficiency virus infected patients have been reported to be at risk of cardiovascular diseases, (CVD) mostly due to the use of antiretroviral agents.8,9 Protease inhibitors have been mostly implicated.10 All these are also connected to fat redistribution dyslipidemia and insulin resistance observed in HIV patients;11,12 thus, this study aims to report on the changes in fibrinolytic activity in HIV infected pregnant women who are undergoing HAART.     

Progress in allogenic bone marrow and peripheral blood stem cell transplantation for multiple myeloma: a comparison between transplants performed 1983--93 and 1994--8 at European Group for Blood and Marrow Transplantation centres

Out of 690 allogeneic matched sibling donor transplants for multiple myeloma reported to the European Group for Blood and Marrow Transplantation (EBMT) registry, 334 were performed during the period 1983-93 (all with bone marrow) and 356 during 1994-98 [223 with bone marrow and 133 with peripheral blood stem cells (PBSCs)]. The median overall survival was 10 months for patients transplanted during the earlier time period and 50 months for patients transplanted with hone marrow during the later period. The use of PBSCs was associated with earlier engraftment but no significant survival benefit compared to bone marrow transplants during the same time period. The improvement in survival since 1994 with the result of a significant reduction in transplant-related mortality, which was 38%, 21% and 25% at 6 months and 46%, 30% and 37% at 2 years during the earlier period, and the later period with bone marrow and PBSCs respectively. Reasons for the reduced transplant-related mortality appeared to be fewer deaths owing to bacterial and fungal infections and interstitial pneumonitis, in turn a result of earlier transplantation and less prior chemotherapy. Better supportive treatment and more frequent use of cytokines may also play a role. The improvement in survival was not directly related to the increased use of PBSCs.     

A non-ATP-competitive inhibitor of BCR-ABL overrides imatinib resistance

Imatinib, which is an inhibitor of the BCR-ABL tyrosine kinase, has been a remarkable success for the treatment of Philadelphia chromosome-positive (Ph+) chronic myelogenous leukemias (CMLs). However, a significant proportion of patients chronically treated with imatinib develop resistance because of the acquisition of mutations in the kinase domain of BCR-ABL. Mutations occur at residues directly implicated in imatinib binding or, more commonly, at residues important for the ability of the kinase to adopt the specific closed (inactive) conformation to which imatinib binds. In our quest to develop new BCR-ABL inhibitors, we chose to target regions outside the ATP-binding site of this enzyme because these compounds offer the potential to be unaffected by mutations that make CML cells resistant to imatinib. Here we describe the activity of one compound, ON012380, that can specifically inhibit BCR-ABL and induce cell death of Ph+ CML cells at a concentration of <10 nM. Kinetic studies demonstrate that this compound is not ATP-competitive but is substrate-competitive and works synergistically with imatinib in wild-type BCR-ABL inhibition. More importantly, ON012380 was found to induce apoptosis of all of the known imatinib-resistant mutants at concentrations of <10 nM concentration in vitro and cause regression of leukemias induced by i.v. injection of 32Dcl3 cells expressing the imatinib-resistant BCR-ABL isoform T315I. Daily i.v. dosing for up to 3 weeks with a >100 mg/kg concentration of this agent is well tolerated in rodents, without any hematotoxicity.