Effects of amifostine on perfused isolated rat heart and on acute doxorubicin-induced cardiotoxicity

Purpose: To determine the effects of amifostine on an isolated perfused rat-heart model and its protective activity with regard to cardiotoxic doxorubicin perfusion. Methods: Langendorff constant-pressure isolated rat-heart preparations were used to analyze the effects of the drugs during a 40-min period of perfusion after a 20-min stabilization interval. The first study was conducted with amifostine alone (controls and 10⁻⁶, 10⁻⁵, and 10⁻⁴ M amifostine; n=6 in each group). The second study was conducted with amifostine and doxorubicin (controls, 2.5 × 10⁻⁵ M doxorubicin, 2.5 × 10⁻⁵ M doxorubicin and 10⁻⁵ M amifostine, and 2.5 × 10⁻⁵ M doxorubicin and 10⁻⁴ M amifostine; n=4 in each group). Results: Amifostine had no significant effect on hemodynamic parameters at 10⁻⁶, 10⁻⁵, and 10⁻⁴ M concentrations. However, amifostine increased the coronary flow expressed as a percentage ± SEM of the baseline flow as follows: 82 ± 4% for controls, 95 ± 6% for 10⁻⁶ M amifostine, (P=0.13), 111 ± 4% for 10⁻⁵ M amifostine (P < 0.01), and 104 ± 3% for 10⁻⁶ M amifostine (P < 0.01). When we commenced an amifostine perfusion 20 min in advance of and then during a 40-min perfusion with doxorubicin, at a cardiotoxic concentration of 2.5 × 10⁻⁵ M the left ventricular pressures (LVDP, expressed as percentages ± SEM of the baseline LVDP before doxorubicin) were 55 ± 3% for the doxorubicin controls, 68 ± 2% for doxorubicin with 10⁻⁵ M amifostine (P=0.05), and 80 ± 3% for doxorubicin with 10⁻⁴ M amifostine (P < 0.01). Whether this protective effect might be related to the known free-radical-scavenging activity of amifostine remains to be determined. Conclusion: On a Langendorff-type model of rat heart, 10⁻⁵ and 10⁻⁴ M amifostine alone induced a coronary dilation and, when associated with a cardiotoxic concentration of 2.5 × 10⁻⁵ M doxorubicin, 10⁻⁵ and 10⁻⁴ M amifostine displayed a cardioprotective effect. Received: 9 March 1998 / Accepted: 6 July 1998     

Vaginal Transposition of the Ovary in Primates (Papio Cynocephalus and Macaca Arctoides)

Experimental data indicate that the time and mechanism of ovulation play a significant role in some cases of infertility and in a broad range of reproductive abnormalities. In order to establish a new experimental model for the study of these phenomena in primates, transposition of the ovary from the pelvis into the vaginal fornix was attempted in 2 species of monkeys: (a) Macaca Arctoides and (b) Papio Cynocephalus. Particularly in the latter species, ovarian relocation into the anterior and the posterior vaginal fornices proved feasible. Most ovaries continued functioning in their new location during the 2-5 months of the follow-up, despite macroscopic and microscopic evidence of infection. Post mortem examination of one of the experimental animals several years after the surgical procedure revealed the presence of an intact functioning ovary still in close contact with the vaginal fornix.     

Activation of peripheral mitochondrial benzodiazepine receptors in the hippocampus stimulates allopregnanolone synthesis and produces anxiolytic-like effects in the rat

RATIONALE AND OBJECTIVES: Stimulation of the mitochondrial benzodiazepine receptor (MBR) in the brain activates the synthesis of neurosteroids that can act as positive modulators of the GABA(A) receptor complex. Allopregnanolone is a potent anxiolytic, anticonvulsant, sedative and hypnotic GABAergic neurosteroid. The anxiolytic-like effects of FGIN 1-27, an MBR agonist, were determined after microinjection into the dorsal hippocampus. METHODS: Behavior in the elevated plus-maze was assessed in adult male rats after bilateral injections of 0, 1.25, 2.5, or 5 microg FGIN 1-27. The behavioral effects of FGIN 1-27 were also determined in animals receiving intrahippocampal co-administration of 20 ng picrotoxin, 5 microg flumazenil, or 200 ng PK 11195. The effects of FGIN 1-27 on behavior in the elevated plus-maze and shock-probe burying test were measured in animals pretreated systemically with 10 mg/kg 4-MA, a 5alpha-reductase inhibitor. Hippocampal and blood plasma levels of allopregnanolone were measured in separate groups of animals pretreated with 4-MA and receiving an intrahippocampal injection of FGIN 1-27. RESULTS: Intrahippocampal injections of FGIN 1-27 produced anxiolytic-like effects in the plus-maze and in the shock-probe burying test. Hippocampal and blood levels of allopregnanolone were also increased by FGIN 1-27. The anxiolytic-like effects of FGIN 1-27 were attenuated by PK 11195 and were blocked by picrotoxin and 4-MA pretreatment, but remained unaffected by flumazenil pretreatment. The neurosteroidogenic effect of FGIN 1-27 was also eliminated by 4-MA. CONCLUSION: Activation of the MBR in the hippocampus leads to the synthesis of allopregnanolone, an anxiolytic neurosteroid that potentiates GABA(A) receptor function.     

Immunologic privilege in the central nervous system and the blood–brain barrier

The brain is in many ways an immunologically and pharmacologically privileged site. The blood–brain barrier (BBB) of the cerebrovascular endothelium and its participation in the complex structure of the neurovascular unit (NVU) restrict access of immune cells and immune mediators to the central nervous system (CNS). In pathologic conditions, very well-organized immunologic responses can develop within the CNS, raising important questions about the real nature and the intrinsic and extrinsic regulation of this immune privilege. We assess the interactions of immune cells and immune mediators with the BBB and NVU in neurologic disease, cerebrovascular disease, and intracerebral tumors. The goals of this review are to outline key scientific advances and the status of the science central to both the neuroinflammation and CNS barriers fields, and highlight the opportunities and priorities in advancing brain barriers research in the context of the larger immunology and neuroscience disciplines. This review article was developed from reports presented at the 2011 Annual Blood-Brain Barrier Consortium Meeting.     

The distribution of 5-HT(6) receptors in rat brain: an autoradiographic binding study using the radiolabelled 5-HT(6) receptor antagonist [(125)I]SB-258585

We used the highly selective 5-HT(6) receptor radioligand [(125)I]SB-258585 (4-iodo-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzene-sulfonamide) to perform autoradiographic binding studies on the rat brain. High levels of specific binding occurred in the corpus striatum, nucleus accumbens, Islands of Calleja and the olfactory tubercle. A high level of binding also appeared in the choroid plexus. Moderate levels occurred in several regions of the hippocampal formation and in certain regions of the cerebral cortex, thalamus, hypothalamus, and substantia nigra; and very low levels in the globus pallidus, cerebellum, other mesencephalic regions, and the rhombencephalon. Displacement of total binding with 10 microM unlabelled SB-214111 (4-bromo-N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]benzene-sulfonamide), another selective 5-HT(6) receptor antagonist, or 10 microM unlabelled methiothepin, reduced binding to barely discernible levels. Some animals received unilateral injections of 6-hydroxydopamine (6-OHDA) into the median forebrain bundle to lesion the nigro-striatal pathway before autoradiographic examination. Effectiveness of the 6-OHDA lesions in the substantia nigra and striatum was confirmed with tyrosine hydroxylase immunohistochemistry. Such lesions resulted in no significant changes in [(125)I]SB-SB258585 binding in any brain region examined, suggesting that 5-HT(6) receptors in the striatum are not located on dendritic, somatic or terminal elements of dopaminergic neurones. Thus, the striatal binding sites seen in this study may be on intrinsic GABAergic or cholinergic neurones, or on terminals of projection neurones from the thalamus or cerebral cortex. The 5-HT(6) receptor ligand binding seen here in the striatum, accumbens, olfactory tubercle, Islands of Calleja, cerebral cortex and hippocampus are in concordance with previous immunohistochemical studies, and suggest a possible involvement of 5-HT(6) receptors in locomotor control, cognition, memory, and control of affect. The high levels of binding observed in the choroid plexus in this study have not been reported before. This finding suggests that 5-HT(6) receptors could play a role in the control of cerebrospinal fluid dynamics.     

Autopsy-confirmed Alzheimer's disease versus clinically diagnosed Alzheimer's disease in the Cache County Study on Memory and Aging: a comparison of quantitative MRI and neuropsychological findings

Atrophy of specific, regional, and generalized brain structures occurs as a result of the Alzheimer's disease (AD) process. Comparing AD patients with histopathological confirmation of the disease at autopsy to those without autopsy but who were clinically diagnosed using the same antemortem criteria will provide further evidence of the utility and accuracy of neuropsychological assessments at the time of diagnosis, as well as the efficacy of quantitative magnetic resonance imaging (qMRI) in demonstrating gross neuropathological changes associated with the disease. The Cache County Study of Aging provides a unique opportunity to determine how closely AD subjects with only the clinical diagnosis match similarly diagnosed AD subjects but with postmortem confirmation of the disease. qMRI volumes of various brain structures, as well as neuropsychological outcome measures from an expanded battery, were obtained in 31 autopsy-confirmed AD subjects and 45 clinically diagnosed AD subjects. Of the various qMRI variables examined, only total temporal lobe volume was different, where those with postmortem confirmation had reduced volume. No significant differences between the two groups were found with any of the neuropsychological outcome measures. These findings confirm the similarity in neuroimaging and neuropsychological assessment findings between those with just the clinical diagnosis of AD and those with an autopsy-confirmed diagnosis in the moderate-to-severe stage of the disease at the time of diagnosis.     

Evidence for high seroprevalence of Taenia solium cysticercosis in individuals from three rural communities in Venezuela

A serological study was undertaken in 1998 to evaluate levels of Taenia solium cysticercosis in 3 rural Venezuelan communities. Infection with viable metacestodes was diagnosed with a trapping enzyme-linked immunosorbent assay (ELISA) that detects a secreted product of viable parasites. Anti-metacestode antibodies were assayed by ELISA using T. solium vesicular fluid as antigen. A total of 1254 sera was collected from 3 communities (Canoabo, Sanare, and Rio Tocuyo) where previous studies had suggested the presence of T. solium. Our results demonstrate an unusually high seroprevalence of cysticercosis, indicating an attendant risk of transmitting the disease to other areas. The seroprevalence of infection with viable cysts, as indicated by detection of circulating parasite antigen, was 9.1% in Canoabo, 6.1% in Sanare, and 5.7% in Rio Tocuyo. The corresponding frequency of antibodies to T. solium cyst antigens was 36.5% in Canoabo, 36.5% in Sanare, and 4% in Rio Tocuyo. As these communities are probably representative of many others in Venezuela, T. solium cysticercosis may be a significant public health problem and more work is certainly indicated. An important finding was that local knowledge of the disease and its transmission do not necessarily guarantee diminished disease prevalence, indicating a lack of appropriate vigilance towards disease control.     

The hepatic arterial blood flow response to portal vein occlusion in the dog

The acute effect of portal vein occlusion on hepatic arterial blood flow was studied in a group of nine anaesthetised dogs. The influence of hepatic artery denervation and total liver denervation on the hepatic arterial flow response was determined subsequently. Blood flows in the hepatic artery and portal vein were measured with electromagnetic flowmeters, and hepatic tissue perfusion with⁸⁵Krypton clearance. A side-to-side mesocaval shunt was constructed to provide a drainage channel for the mesenteric venous blood during the periods of portal vein occlusion.Occlusion of the portal vein produced an immediate and significant increase in hepatic arterial flow which was sustained at approximately 80% above control for the 6 min period of observation. Total liver blood flow and hepatic tissue perfusion were both significantly reduced by about 40%. Denervation either of the hepatic artery alone or the entire liver produced no change in the response, and it is concluded that there is no neurogenic component either initiating or modifying the early changes in hepatic arterial flow.     

Estrogen-progestogen once-a-month injectable contraceptives and serum prolactin

To assess the effect of hormonal monthly injectable contraceptives upon the serum values of immunoreactive prolactin (Prl), three groups of women of reproductive age exposed to different estrogen-progestogen injectable formulation for a minimum of one year were studied. The first group (n = 10) received dihydroxyprogesterone acetophenide 150 mg and estradiol enanthate 10 mg (DHPA/E2-EN), Group 2 (n = 21) received medroxyprogesterone acetate 25 mg and estradiol cypionate 5 mg (MPA/E2-C) and Group 3 (n = 19) was exposed to norethisterone enanthate 50 mg and estradiol valerate 5 mg (NET-EN/E2-V). A group of IUD users (n = 16) served as the control group. Serum Prl and 17 beta-estradiol (E2) concentration were determined in blood samples (0 and 15 min.) on days 0 (day of last injection), 10, 20 and 30 after last contraceptive injection. The results demonstrated a slight though not significant increase (p greater than 0.05) in serum Prl in the three experimental groups as compared with the IUD control group. This increase in Prl levels observed on day 10 post-last injection never exceeded the upper limits of the normal range (20 ng/ml). Overall, the data demonstrated that the chronic administration of these estrogen/progestogen once-a-month injectable contraceptives does not affect the Prl baseline secretion in women.     

Study of telomere length reveals rapid aging of human marrow stromal cells following in vitro expansion

Human marrow stromal cells (MSCs) can be isolated from bone marrow and differentiate into multiple tissues in vitro and in vivo. These properties make them promising tools in cell and gene therapy. The lack of a specific MSC marker and the low frequency of MSCs in bone marrow necessitate their isolation by in vitro expansion prior to clinical use. This may severely reduce MSC proliferative capacity to the point that the residual proliferative potential is insufficient to maintain long-term tissue regeneration upon reinfusion. In this study we determined the effect of in vitro expansion on the replicative capacity of MSCs by correlating their rate of telomere loss during in vitro expansion with their behavior in vivo. We report that even protocols that involve minimal expansion induce a rapid aging of MSCs, with losses equivalent to about half their total replicative lifespan.