Increased tyrosine hydroxylase immunoreactivity in the rat cortex following prenatal cocaine exposure.

Cocaine has been found to be a neurobehavioral teratogen in both animals and humans. In this study the effects of cocaine on the developing catecholamine systems were examined. Rats were treated gestationally with cocaine (40 mg/kg s.c.) or saline from gestational day 13 until parturition. On postnatal day 28, tyrosine hydroxylase immunocytochemistry was performed. Increases in catecholamine fiber densities were observed in the hippocampus, anterior cingulate cortex, and parietal cortex in cocaine-treated animals. These findings may explain some of the behavioral alterations seen following prenatal cocaine exposure.     

Effects of 5,7-dihydroxytryptamine on HRP retrograde transport from hippocampus to midbrain raphe nuclei in the rat

The combination of horseradish peroxidase (HRP) retrograde tracing and specific lesioning using 5,7-dihydroxytryptamine (5,7-DHT) was applied to the midbrain raphe-hippocampal system. Serotonergic fibers from the median raphe nucleus (MRN) of the rat reach the dorsal hippocampus (HIPP) through the cingulum bundle (CB) and the fornix-fimbria (FF). Intracerebral microinjections of 5,7-DHT in these two bundles were made at various times before HRP injections into the dorsal HIPP. After both CB and FF lesion, the number of labeled cells in MRN is reduced to 49.6% at zero time (HRP injected immediately after 5,7-DHT) and to 6.5% after 2 days. There was no significant effect on the number of labeled cells in the locus ceruleus. Selective lesioning of 5-HT fibers in the CB or the FF revealed that raphe-CB-HIPP neurons and raphe-FF-HIPP neurons have a similar distribution pattern in the MRN, but that a dorsal group of neurons at the junction of MRN and dorsal raphe nucleus took the CB route exclusively to innervate the HIPP. The CB pathway was used by more neurons (55% of total number of labeled neurons) than was the FF (21%). An appreciable number of fibers (23%) appear to have branches in both pathways. Our findings are discussed with regard to the recovery of HIPP function seen after long term destruction of 5-HT fibers in the CB.     

Binding of 1-α -acetylmethadol and its metabolites to blood constituents

The distribution in vitro of (-)1-α-acetylmethadol (LAAM) in human blood constituents was studied. In concentrations close to those found in humans who are maintained on LAAM (0.35 nmole/ml serum), the drug was distributed almost evenly between plasma proteins and red blood cells. At similar concentrations of the drug in plasma alone, over 80 per cent was bound to protein. The strength of binding to proteins was very weak, as demonstrated by our inability to obtain a protein-LAAM complex by conventional Sephadex G-200 column chromatography. However, equilibration and elution of the column with buffer containing 0.35 nM drug, using [³H]LAAM as tracer, allowed the identification of a LAAM-protein complex. The fraction responsible for the bulk of LAAM binding in serum was identified as an α-globulin with a molecular weight of about 400,000. Equilibrium dialysis experiments showed that the role played by albumin in the binding of LAAM was insignificant. The binding of LAAM to serum proteins was highly reversible, as attested by the displacement of [³H]LAAM from its binding sites by unlabeled drug. The major metabolites of LAAM, noracetylmethadol and dinor-acetylmethadol, were also weakly and reversibly bound by serum proteins and competed with LAAM for protein binding sites. A Scatchard plot, after equilibrium dialysis of various concentrations of LAAM against human serum, indicates that the maximum specific binding of drug was 8.2 nmoles/ml serum. These data suggest that, assuming at least one binding site per protein molecule, the binding occurs to a protein of very low concentration (about 1 mg/ml) in plasma. This is consistent with the data that suggest an insignificant role of human serum albumin in the binding of LAAM and the identification of a very high molecular weight protein as the possible binding entity. The data suggest that LAAM, its metabolites, and methadone compete for the same protein binding sites and that the binding capacities of plasma for both LAAM and methadone are of the same order of magnitude. The results failed to show any cooperativity on the plasma protein binding of LAAM, its metabolites or methadone.     

DIfferential effects of prenatal and postnatal acth or nicotine exposure on 5-HT high affinity uptake in the neonatal rat brain

These studies were designed to examine the differential effects of prenatal or postnatal administration of ACTH 1-39 and nicotine, on 5-HT high affinity uptake in brainstem and hippocampal synaptosomes. ACTH was administered prenatally (to pregnant dams) and postnatally to the neonates. Postnatal administration of ACTH significantly increased high-affinity 5-HT uptake in the hippocampus and especially the brainstem at both 7 and 21 days after birth. Prenatal ACTH, on the other hand, transiently increased 5-HT uptake in only the brainstem at 7 days, a change that was reversed at 21 days. While the effects of postnatal nicotine administration were essentially the same as those of postnatal ACTH treatment, prenatal nicotine, unlike ACTH, did not alter 5-HT uptake in 7-day-old rats but did reduce uptake in both tissues at 21 days. The observation that postnatal nicotine mimics the effects of postnatal ACTH and that nicotine stimulates ACTH release, suggests that the postnatal effects of nicotine may be exerted through ACTH.     

Subcellular distribution of lysosomal enzymes in the human endometrium. I. Normal menstrual cycle

The changes in the activity and in the subcellular distribution of three lysosomal enzymes have been studied in the normal human endometrium during the menstrual cycle by the use of highly sensitive fluorimetric technics. Total activity of lysosomal enzymes increased during the maturation of the endometrial tissue from the proliferative to the secretory phase. This increase is greater (105%) for N-acetyl-β-D-glucosaminidase, than for acid phosphatase (77%) or β-glucuronidase (65%). During the proliferative phase the relative activity of the three enzymes found free in the cell cytoplasm was similar and ranged from 21% for N-acetyl-glucosaminidase to 32% for β-glucuronidase. The main difference found between the proliferative and the secretory phase of the menstrual cycle was a drastic increase -- both absolute and relative -- of the cytoplasmic free activity of the lysosomal enzymes. The increase in total free activity represented approximately two, three and four times the amount found free during the proliferative phase for β-glucuronidase, acid phosphatase and N-acetyl-glucosaminidase, respectively. In all cases the relative activity found free represented almost 50% of the total enzymatic activity. The membrane bound activity of the three enzymes also showed a significant increase during the secretory phase, although less dramatic than the free activity.     

The pharmacokinetics of ketamine following intramuscular injection to F344 rats

Ketamine is a glutamate N‐methyl‐D‐aspartate receptor antagonist that is a rapid‐acting dissociative anesthetic. It has been proposed as an adjuvant treatment along with other drugs (atropine, midazolam, pralidoxime) used in the current standard of care (SOC) for organophosphate and nerve agent exposures. Ketamine is a pharmaceutical agent that is readily available to most clinicians in emergency departments and possesses a broad therapeutic index with well‐characterized effects in humans. The objective of this study was to determine the pharmacokinetic profile of ketamine and its active metabolite, norketamine, in F344 rats following single or repeated intramuscular administrations of subanesthetic levels (7.5 mg/kg or 30 mg/kg) of ketamine with or without the SOC. Following administration, plasma and brain tissues were collected and analyzed using a liquid chromatography–mass spectrometry method to quantitate ketamine and norketamine. Following sample analysis, the pharmacokinetics were determined using non‐compartmental analysis. The addition of the current SOC had a minimal impact on the pharmacokinetics of ketamine following intramuscular administration and repeated dosing at 7.5 mg/kg every 90 minutes allows for sustained plasma concentrations above 100 ng/mL. The pharmacokinetics of ketamine with and without the SOC in rats supports further investigation of the efficacy of ketamine co‐administration with the SOC following nerve agent exposure in animal models.     

A Continuing HIV Epidemic and Differential Patterns of HIV-STI Risk among MSM in Quito, Ecuador: An Urgent Need to Scale Up HIV Testing and Prevention

This study characterized the HIV epidemic among men who have sex with men (MSM) in Quito, Ecuador and contrasted risk patterns with other STI’s. 416 MSM ages 15 years and older were recruited using respondent-driven sampling in 2010–2011. Biological testing and a self-interview survey assessed HIV and STI infections and risk behaviors. Analysis incorporated recruiter-level variables and clustering adjustments to control for recruitment patterns. We identify high levels of HIV (11 %), HSV-2 (14 %) and active syphilis (5.5 %) infections, low levels of lifetime HIV testing (57 %), limited knowledge of HIV and STI’s (<48 %) and limited consistent condom use independent of partner type (<40 %). Sex work was associated with all infections while associations with residential location, how casual partners are met and other variables, varied. Scale-up of behavioral prevention and HIV testing is urgently needed. Interventions should target male sex workers and exploit differential patterns of HIV-STI risk to stay ahead of the epidemic.     

Serum and synovial fluid inhibitors of antibody-mediated lymphocytotoxicity in rheumatoid arthritis and systemic lupus erythematosus

Many sera from patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) inhibit lymphocyte-dependent antibody cytotoxicity (LDAC). RA synovial fluids also inhibit LDAC. RA serum inhibition was present in high molecular weight and 5S serum fractions, whereas in SLE it was confined to 7S fractions. A correlation between rheumatoid factor activity and LDAC inhibition was noted, and there was some evidence for inhibition of SLE serum acting on effector cells. Inhibition in RA synovial fluid was found in both high molecular weight and very low molecular weight fractions (<4S).