Lack of acute d-amphetamine effects on thyrotropin release

Case reports have suggested that amphetamine abuse causes excessive secretion of thyrotropin (TSH) and thyroxine (T4). Such an amphetamine-induced effect might be noradrenergic-mediated in the hypothalamus. The current controlled study examined oral d-amphetamine effects on the hypothalamic-pituitary-thyroid axis in normal humans. No acute effects were seen on TSH, T3 or T4 levels. d-Amphetamine elevated cortisol levels at 180 min, as previously reported.     

Lymphoid subpopulation changes after thermal injury and thermal injury with infection in an experimental model.

Subpopulation analysis of peripheral blood lymphocytes is a frequently used measure of immunocompetence. Yet, little is known about the lymphocyte subpopulations in the circulation and lymphoid organs after severe trauma. Blood, spleen, and lymph node (LN) subpopulations were compared in a rat model of burn injury (B) and burn injury with infection (BI). B and BI rats received 30% total body surface scald burns. Infection was induced by seeding wounds with Pseudomonas aeruginosa. Subpopulations were identified by flow cytometry 48 hours after burn. Helper lymphocytes were selectively depleted from the circulation of BI but not B animals, which caused the ratio of helper to suppressor cells (HSR) in BI animals to decrease significantly compared with the unburned controls. Both LN helper and suppressor cells were decreased in BI animals and the HSR was unchanged, but a selective reduction in suppressor cells in B LN increased the HSR relative to unburned controls. Spleen subpopulations were unchanged for both B and BI groups. Subpopulation changes after trauma and infection were different for each tissue examined.     

Reduction in acute rejections decreases chronic rejection graft failure in children: a report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS).

Chronic rejection accounted for 32% of all graft losses in 7123 pediatric transplants. In a previous study acute, multiple acute and late acute rejections were risk factors for the development of chronic rejection. We postulated that the recent decrease in acute rejections would translate into a lower risk for chronic rejection among patients with recent transplants. We reviewed our data on patients transplanted from 1995 to 2000, and using multivariate analysis and a proportional hazards model developed risk factors for patients whose grafts had failed due to chronic rejection. A late initial rejection increased the risk of chronic rejection graft failure 3.6-fold (p < 0.001), while a second rejection resulted in further increase of 4.2-fold (p < 0.001). Recipients who received less than 5 mg/kg of cyclosporine at 30 days post-transplant had a relative risk (RR) of 1.9 (p = 0.02). Patients transplanted from 1995 to 2000 had a significantly lower risk (RR = 0.54, p < 0.001) of graft failure from chronic rejection than those who received their transplants earlier (1987-94). Since we were able to demonstrate that there is a decreased risk of chronic rejection graft failure in our study cohort, we would conclude that the goal of future transplants should be to minimize acute rejections.     

Central opioid receptors differentially regulate the nalmefene-induced suppression of ethanol- and saccharin-reinforced behaviors in alcohol-preferring (P) rats.

The exact opioid-sensitive receptors participating in EtOH-seeking behaviors remains unclear. Previous studies have reported higher densities of micro-opioid receptor binding in the nucleus accumbens (NACC) of P relative to NP rats; however, no differences were seen in delta-receptor binding. In contrast to the NACC, substantially lower levels of micro-receptor binding have been observed in the ventral tegmental area (VTA) of both P and NP rats, albeit no line differences have been observed. In the present study, opioid receptors in the NACC, VTA, and hippocampus were evaluated for their capacity to regulate both EtOH- and saccharin-motivated behaviors in the genetically selected alcohol-preferring (P) rat. To accomplish this, nalmefene, an opiate antagonist with preferential binding affinity for the micro-opioid receptor was unilaterally or bilaterally infused during concurrent availability of 1 h daily EtOH (10% v/v) and saccharin (0.025 or 0.050% w/v) solutions. Rats performed under a two-lever fixed ratio (FR) schedule in which four responses on one lever produced the EtOH solution, and four on a second lever produced the saccharin solution. The results demonstrated that when responding maintained by both EtOH and saccharin are matched at basal levels, unilateral (1-60 microg) or bilateral (0.5-10 microg) microinjections of nalmefene into the NACC produced selective dose-dependent reductions on responding maintained by EtOH. Unilateral (40, 60 microg) and bilateral (10 microg) VTA infusions were also observed to selectively reduced EtOH responding; however, greater nalmefene doses were required and the magnitude of suppression on EtOH responding was markedly less compared with the NACC. The greater sensitivity of nalmefene to suppress EtOH responding in the NACC is likely due to the greater number of opioid receptors in the NACC relative to the VTA. Only bilateral infusion of the 40 microg dose in the NACC and VTA suppressed responding maintained by both EtOH and saccharin. In contrast, intrahippocampal infusions dose dependently suppressed EtOH- and saccharin-maintained responding over a range of doses (1-20 microg). The present study provides evidence that nalmefene suppresses EtOH-motivated behaviors via blockade of opioid receptors within the NACC and VTA, and under various dose conditions both reinforcer and neuroanatomical specificity can be observed.     

Germline mutations in the neurofibromatosis type 2 tumour suppressor gene

The recent identification of the NF2 tumour suppressor genehas enabled large scale screening for pathological mutationsin the gene. We have sought germline mutations In the NF2 geneby SSCP and heteroduplex analysis of cDNA and genomic DNA samplesfollowed by cloning and sequencing of mutant alleles. In thepresent report we describe 11 putative pathological mutations,including five nonsense mutations, three short insertions ordeletions cauing frameshifts and three missense mutations. Moststop mutations and frameshift mutations were found In Individualsexpressing a severe phenotype while one of the three missensemutations was associated with a mild phenotype. Four unrelatedNF2 patients of the 93 tested were found to have identical nonsensemutations caused by a C to T transition (C169) in a CpG dinucleotide,which is a potential mutational hotspot in the NF2 tumour suppressorgene.     

Serum erythropoietin quantitation in pregnancy using an enzyme-linked immunoassay.

During normal pregnancy there is a decrease in the hematocrit due to a disproportionate increase in the blood volume compared with the red cell mass. Using a new enzyme-linked immunoassay (Amgen Diagnostics), serum erythropoietin was quantified in normal nonanemic pregnancies throughout gestation and in third trimester anemic patients. We found that the mean hematocrit in normal pregnancy reached a nadir late in the second trimester and the serum erythropoietin plateaued at a 50% increase. Those pregnancies complicated by anemia defined by a hematocrit less than 30 vol% demonstrated a statistically significant increase in serum erythropoietin above those not anemic.