GSK-3ß dysregulation contributes to parkinson's-like pathophysiology with associated region-specific phosphorylation and accumulation of tau and α-synuclein.

Aberrant posttranslational modifications (PTMs) of proteins, namely phosphorylation, induce abnormalities in the biological properties of recipient proteins, underlying neurological diseases including Parkinson's disease (PD). Genome-wide studies link genes encoding α-synuclein (α-Syn) and Tau as two of the most important in the genesis of PD. Although several kinases are known to phosphorylate α-Syn and Tau, we focused our analysis on GSK-3ß because of its accepted role in phosphorylating Tau and to increasing evidence supporting a strong biophysical relationship between α-Syn and Tau in PD. Therefore, we investigated transgenic mice, which express a point mutant (S9A) of human GSK-3ß. GSK-3ß-S9A is capable of activation through endogenous natural signaling events, yet is unable to become inactivated through phosphorylation at serine-9. We used behavioral, biochemical, and in vitro analysis to assess the contributions of GSK-3ß to both α-Syn and Tau phosphorylation. Behavioral studies revealed progressive age-dependent impairment of motor function, accompanied by loss of tyrosine hydroxylase-positive (TH+ DA-neurons) neurons and dopamine production in the oldest age group. Magnetic resonance imaging revealed deterioration of the substantia nigra in aged mice, a characteristic feature of PD patients. At the molecular level, kinase-active p-GSK-3ß-Y216 was seen at all ages throughout the brain, yet elevated levels of p-α-Syn-S129 and p-Tau (S396/404) were found to increase with age exclusively in TH+ DA-neurons of the midbrain. p-GSK-3ß-Y216 colocalized with p-Tau and p-α-Syn-S129. In vitro kinase assays showed that recombinant human GSK-3ß directly phosphorylated α-Syn at a single site, Ser129, in addition to its known ability to phosphorylate Tau. Moreover, α-Syn and Tau together cooperated with one another to increase the magnitude or rate of phosphorylation of the other by GSK-3ß. Together, these data establish a novel upstream role for GSK-3ß as one of several kinases associated with PTMs of key proteins known to be causal in PD.

Impact of a primary care physician workshop on osteoporosis medical practices.

SUMMARY: Attendance at a fragility-fractures-prevention workshop by primary care physicians was associated with higher rates of osteoporosis screening and treatment initiation in elderly female patients and higher rates of treatment initiation in high-risk male and female patients. However, osteoporosis management remained sub-optimal, particularly in men. INTRODUCTION: Rates of osteoporosis-related medical practices of primary care physicians exposed to a fragility-fractures-prevention workshop were compared with those of unexposed physicians. METHODS: In a cluster cohort study, 26 physicians exposed to a workshop were matched with 260 unexposed physicians by sex and year of graduation. For each physician, rates of bone mineral density (BMD) testing and osteoporosis treatment initiation among his/her elderly patients 1 year following the workshop were computed. Rates were compared using multilevel logistic regression models controlling for potential patient- and physician-level confounders. RESULTS: Twenty-five exposed physicians (1,124 patients) and 209 unexposed physicians (9,663 patients) followed at least one eligible patient. In women, followed by exposed physicians, higher rates of BMD testing [8.5% versus 4.2%, adjusted OR (aOR) = 2.81, 95% CI 1.60-4.94] and treatment initiation with bone-specific drugs (BSDs; 4.8% vs. 2.4%, aOR = 1.95, 1.06-3.60) were observed. In men, no differences were detected. In patients on long-term glucocorticoid therapy or with a previous osteoporotic fracture, higher rates of treatment initiation with BSDs were observed in women (12.0% vs. 1.9%, aOR = 7.38, 1.55-35.26), and men were more likely to initiate calcium/vitamin D (5.3% vs. 0.8%, aOR = 7.14, 1.16-44.06). CONCLUSIONS: Attendance at a primary care physician workshop was associated with higher rates of osteoporosis medical practices for elderly women and high-risk men and women. However, osteoporosis detection and treatment remained sub-optimal, particularly in men.

Unique responses to mitochondrial complex I inhibition in tuberoinfundibular dopamine neurons may impart resistance to toxic insult.

Tuberoinfundibular dopamine (TIDA) neurons are spared in Parkinson's disease (PD), a disorder that causes degeneration of midbrain nigrostriatal dopamine (NSDA) and mesolimbic dopamine (MLDA) neurons. This pattern of susceptibility has been demonstrated in acute complex I inhibitor-induced models of PD, and extrinsic factors such as toxin distribution, bioactivation, entry into the cell and sequestration into vesicles are postulated to underlie the resistance of TIDA neurons. In the present experiments, direct exposure to rotenone or 1-methyl-4-phenylpyridinium (MPP+) had no effect on mediobasal hypothalamic TIDA neurons, but significantly increased the percentage of apoptag immunoreactive neurons in midbrain primary NSDA and MLDA cultures. In vivo 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) exposure caused an initial decrease (by 4 h) in dopamine (DA) in brain regions containing axon terminals of TIDA (median eminence [ME]), NSDA (striatum [ST]) and MLDA (nucleus accumbens [NA]) neurons. By 16 h after MPTP treatment, DA concentrations in ME returned to control levels, while ST and NA DA levels remained low up to 32 h after treatment with MPTP. When mice and rats were chronically treated with MPTP and rotenone, respectively, the same pattern of susceptibility emerged. TIDA neurons were unaffected while NSDA neurons suffered loss of cell bodies and axon terminal DA. These experiments demonstrate that the resistance of hypothalamic TIDA neurons is not likely to be due to extrinsic factors, and that further examination of the intrinsic properties of these neurons may elucidate mechanisms that can be translated into neuroprotective strategies in PD.

Complications during apnea testing in the determination of brain death: predisposing factors.

Apnea testing in brain death determination may result in cardiovascular complications. Hypotension occurred in 24% and cardiac arrhythmias occurred in <1% of the 145 apneic oxygenation procedures. Complications were noted in only 15% of apnea tests performed without any predisposing factors. Significantly more complications (39%) were observed in apnea tests with inadequate precautions, particularly in apnea tests without adequate preoxygenation (50%).

No pathogenic mutations in the persyn gene in Parkinson's disease.

The persyn (gamma-synuclein) gene is highly homologous to the alpha-synuclein gene and is highly expressed in the nervous system. It is therefore, an excellent candidate gene for Parkinson's disease. However, we have sequenced the gene in a large number of families with parkinsonism and failed to find pathogenic mutations.

[Supporting the conjugal system during the perinatal period: an experience in participatory research]. / Soutenir le système conjugal pendant la période périnatale: une expérience de recherche participatoire.

This article presents the process and results of a participatory study intended to develop and evaluate preventive interventions for couples in the process of becoming new parents. A total of 21 participants, 4 physicians, 8 couples, and an investigator, studied the interventions using a research approach derived from a constructivist paradigm, the fourth generation evaluation. Employing a family intervention model, the nurse guided and contributed to the investigation. The results enabled physicians to refine their perinatal care and facilitated the couples' adjustment to the arrival of their first child. The interventions, the research process, and the use of a family nursing model are promising for nursing applications.

A pilot course as a model for implementing a PBL curriculum.

Many medical schools are shifting to a problem-based learning (PBL) curriculum, some without any transition period, others using periods of parallel-track curricula. The authors report on and discuss a third strategy for implementing PBL: using a pilot course as a model to facilitate the transition. After the Université de Montréal Faculty of Medicine chose to switch PBL, one course in the third year of the traditional curriculum was changed to PBL format 11 months before the new curriculum was to start in September 1993. This was done to develop local expertise, to gain confidence, to test the feasibility of the method, to produce a showcase, to assess more accurately the resources required, and to provide a practice ground for the curriculum planners and managers and the faculty-development training team. The authors discuss the planning of the pilot course, the training of the faculty in various aspects of PBL (writing problems, tutoring methods, etc.), the course implementation, and the course evaluation. Overall, the pilot course was well received by both the faculty and the students and provided much beneficial information that assisted the university in its transition to a new PBL curriculum.

Periventricular-hypophysial dopaminergic neurons innervate the intermediate but not the neural lobe of the rat pituitary gland.

The purpose of the present study was to determine the relative distribution of axon terminals of A14 periventricular-hypophysial dopaminergic (PHDA) neurons in the neural and intermediate lobes of the rat pituitary gland. Discrete unilateral injections of the anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA-L) into the periventricular nucleus resulted in labelling of extensively branched terminal axonal arbors in the intermediate lobe, but not the neural lobe of the pituitary gland. In contrast, unilateral injections of PHA-L into the paraventricular nucleus revealed thick, varicose terminal arborizations containing PHA-L in the neural lobe, but not the intermediate lobe. Terminal axonal branches and varicosities containing PHA-L immunoreactivity in the intermediate lobe were also immunoreactive for tyrosine hydroxylase. These results reveal that A14 PHDA neurons originating in the periventricular nucleus of the hypothalamus project axons to the intermediate lobe of the rat pituitary gland.

gamma-Aminobutyric acid receptor-mediated regulation of periventricular-hypophysial dopaminergic neurons: possible role in mediating stress- and 5-hydroxytryptamine-induced decreases in neuronal activity.

The present study examined the effects of gamma-aminobutyric acid (GABA) agonists and antagonists on basal periventricular-hypophysial dopaminergic (PHDA) neuronal activity with a focus on the role of endogenous GABA in mediating 5-hydroxytryptamine- and stress-induced decreases in PHDA neuronal activity. PHDA neuronal activity was estimated by measuring concentrations of 3,4-dihydroxyphenylacetic acid (DOPAC) in terminals of these neurons in the intermediate lobe of the pituitary. Plasma concentrations of alpha-melanocyte-stimulating hormone (alpha MSH) also were determined to provide a further index of PHDA neuronal activity. Administration of the GABAB agonist baclofen, but not the GABAA agonist isoguvacine, produced dose- and time-related decreases in intermediate lobe DOPAC concentrations and corresponding increases in plasma alpha MSH concentrations. Administration of either the GABAA antagonist SR-95,531 [2-(3-carboxypropyl)-3-amino-6-(4-methoxyphenyl)-pyridazinium bromide] or GABAB antagonists 2-hydroxysaclofen and CGP-35,348 [P-(3-aminopropyl)-P-diethoxymethyl-phosphinic acid; SR-95-531 did not alter basal intermediate lobe DOPAC concentrations or plasma alpha MSH concentrations per se, indicating that endogenous GABA does not tonically inhibit PHDA neuronal activity or alpha MSH secretion. 2-Hydroxysaclofen and CGP-35,348 did, however, reverse the baclofen-induced decrease in intermediate lobe DOPAC concentrations and increase in plasma alpha MSH concentrations. In a similar fashion, 2-hydroxysaclofen blocked the inhibitory effects of stress and the 5-hydroxytryptamine2/1c receptor agonist DOI [1-(2,5-dimethoxy-4-iodophenyl-2-aminopropane] on PHDA neuronal activity. These results indicate that GABAB and not GABAA receptor activation inhibits basal PHDA neuronal activity, and that GABAB receptor activation mediates the inhibitory effects of 5-hydroxytryptamine and stress on PHDA neurons.

GABAergic regulation of tuberoinfundibular dopaminergic neurons in the male rat.

The purpose of the present study was to examine the effects of gamma-aminobutyric acid (GABA)A and GABAB receptor blockade and activation on the activity of tuberoinfundibular dopaminergic (TIDA) neurons in male rats. The activity of TIDA neurons was estimated by measuring the concentration of the primary dopamine metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in the median eminence. Administration of the GABAA receptor antagonist SR 95531 increased DOPAC concentrations in the median eminence, and decreased plasma concentrations of prolactin, in a dose- and time-related manner. Administration of the GABAA receptor agonist isoguvacine had no effect per se on DOPAC concentrations in the median eminence, but produced a delayed decrease in plasma prolactin concentrations. Isoguvacine pre-treatment prevented the increase in DOPAC concentrations in the median eminence produced by SR 95531. In contrast, administration of the GABAB receptor agonist baclofen decreased DOPAC concentrations in the median eminence, and increased plasma prolactin concentrations in a dose-dependent manner. Administration of the GABAB receptor antagonist 2-hydroxysaclofen had no effect on TIDA neurons per se, but blocked baclofen-induced decreases in DOPAC concentrations in the median eminence and increases in plasma prolactin concentrations. These results indicate that while activation of GABAB receptors inhibits TIDA neurons, these neurons are tonically inhibited by endogenous GABA acting at GABAA but not GABAB receptors.

5-Hydroxytryptamine2 receptor-mediated regulation of periventricular-hypophysial dopaminergic neuronal activity and the secretion of alpha-melanocyte-stimulating hormone.

The present study examined the effects of the 5-hydroxytryptaminergic (5HT)2/1c agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) on periventricular-hypophysial dopaminergic (DA) neuronal activity and the secretion of alpha-melanocyte-stimulating hormone (alpha MSH). For comparison, the effects of DOI on tuberoinfundibular DA neuronal activity and the secretion of prolactin were also examined. Periventricular hypophysial and tuberoinfundibular DA neuronal activities were estimated by measuring the concentrations of 3,4-dihydroxyphenylacetic acid (DOPAC) in the terminal regions of these neurons; i.e., in the intermediate lobe of the pituitary and median eminence, respectively. Acute administration of DOI produced dose- and time-related decreases in intermediate lobe DOPAC concentrations and corresponding increases in plasma alpha MSH concentrations. Pretreatment of animals with either the 5HT2/1c antagonist ritanserin or the selective 5HT2 antagonist alpha-phenyl-1-(2-phenylethyl)-4-piperidine methanol (MDL-11,939) blocked the DOI-induced decrease in intermediate lobe DOPAC concentrations and increase in plasma alpha MSH concentrations. Acute administration of DOI produced dose- and time-related increases in plasma prolactin concentrations but did not alter DOPAC concentrations in the median eminence. Furthermore, the DOI-induced increase in plasma prolactin concentrations was blocked by ritanserin, but not MDL-11,939 pretreatment. Taken together, these data suggest that DOI inhibits periventricular hypophysial DA neuronal activity and increases the secretion of alpha MSH by activating 5HT2 receptors, whereas the DOI-induced prolactin secretion is independent of a decrease in tuberoinfundibular DA neuronal activity and is most likely mediated by 5HT2/1c receptor activation.

5HT2 receptors mediate the effects of stress on the activity of periventricular hypophysial dopaminergic neurons and the secretion of alpha-melanocyte-stimulating hormone.

The roles of 5-hydroxytryptaminergic (5HT) neurons and receptor subtypes in mediating the effects of stress on the activity of periventricular hypophysial dopaminergic (PHDA) neurons and the secretion of alpha-melanocyte-stimulating hormone (alpha MSH) were examined in female rats. Periventricular hypophysial dopaminergic neuronal activity was estimated by measuring concentrations of 3,4-dihydroxyphenylacetic acid in the intermediate lobe of the pituitary. Brief exposure to diethylether followed by 30 min of supine restraint decreased intermediate lobe 3,4-dihydroxyphenylacetic acid concentrations and increased plasma concentrations of alpha MSH. These stress-induced effects were not observed in animals in which 5HT neurons had been previously destroyed by 5,7-dihydroxytryptamine or inhibited by the administration of the 5HT1A receptor agonist 8-hydroxy-2-(di-n-propyl-amino)-tetralin. Pretreatment of rats with the 5HT2 receptor antagonist MDL-11,939 blocked the inhibitory effects of stress on intermediate lobe 3,4-dihydroxyphenylacetic acid concentrations and the corresponding increase in plasma alpha MSH concentrations, whereas the 5HT3 receptor antagonist ondansetron was without effect. These results reveal that 5HT neurons, acting via 5HT2 receptors, mediate the inhibitory effects of stress on periventricular hypophysial dopaminergic neurons and the consequent increase in secretion of alpha MSH.

Neurochemical evidence that 5-hydroxytryptaminergic neurons tonically inhibit noradrenergic neurons terminating in the hypothalamus.

The medial zona incerta (MZI) and dorsomedial nucleus of the hypothalamus (DMN), which contain cell bodies and terminals of incertohypothalamic dopaminergic (DA) neurons, are densely innervated by both noradrenergic (NE) and 5-hydroxytryptaminergic (5-HT) neurons. In view of emerging anatomical and pharmacological evidence suggesting possible interactions between 5-HT and catecholaminergic neurons, the effects of experimental procedures that inhibit or disrupt 5-HT neurons on the activities of catecholaminergic neurons terminating in these regions were examined in the present study. Catecholaminergic neuronal activity was estimated by measuring catecholamine synthesis (accumulation of 3,4-dihydroxyphenylalanine [DOPA] after administration of a decarboxylase inhibitor) and metabolism (concentrations of the dopamine metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) and the norepinephrine metabolite 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG)) in the MZI and DMN of both male and female rats. Inhibition of 5-HT neurons following administration of the 5-HT1A autoreceptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) increased the accumulation of DOPA in the DMN and the concentrations of DOPAC in the MZI and DMN, indicating an activation of catecholaminergic neurons in these regions. Concentrations of MHPG were increased in the MZI and DMN by 8-OH-DPAT or 5,7-dihydroxytryptamine-induced lesions of 5-HT neurons, revealing that NE neurons terminating in these regions were activated following procedures that decrease 5-HT neuronal function. Following destruction of NE neurons projecting to the MZI and DMN, 8-OH-DPAT no longer increased DOPAC concentrations in these brain regions.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence that hypothalamic periventricular dopamine neurons innervate the intermediate lobe of the rat pituitary.

The purpose of the present study was to provide neurochemical and endocrinological evidence that dopamine (DA) neurons terminating in the intermediate lobe of the rat pituitary originate in the periventricular nucleus of the hypothalamus. One week following surgical separation of the periventricular nucleus from the mediobasal hypothalamus, DA and 3,4-dihydroxyphenyl-acetic acid (DOPAC) concentrations in the intermediate lobe were reduced by 50%, and this was accompanied by an increase in plasma alpha-melanocyte-stimulating hormone (alpha-MSH) concentrations. In contrast, this procedure had no effect on concentrations of prolactin in the plasma, or DA or DOPAC in the median eminence, the region of the mediobasal hypothalamus containing terminals of tuberoinfundibular DA neurons. Electrical stimulation of the periventricular nucleus increased the ratio of DOPAC/DA in the intermediate lobe and reduced the concentrations of alpha-MSH in the plasma, whereas in these same animals the DOPAC/DA ratio in the median eminence and concentrations of prolactin in the plasma were unaltered. These results indicate that approximately 50% of all the DA neurons terminating in the intermediate lobe of the rat pituitary originate in or project through the periventricular nucleus of the hypothalamus, and that these DA neurons regulate the secretion of alpha-MSH from intermediate lobe melanotrophs.

Disruption of FR-40 by 5-HT agonists. II. Effects of chronic phenelzine or isocarboxazid.

Effects of chronic treatment with the monoamine oxidase inhibitors phenelzine and isocarboxazid on disruption of FR-40 operant responses by 5-HT agonists have been studied. Three groups of rats that were trained in the FR-40 operant schedule showed marked disruption by 0.1 mg/kg IP lysergic acid diethylamide (LSD), 2 mg/kg IP quipazine (Q), 0.05 mg/kg SC 8-hydroxy-2-(di-n-propylamino)tetralin (8-OHDPAT), and 1 mg/kg SC (m-trifluoromethyl-phenyl)piperazine (TFMPP), administered twice weekly in random order. Subsequently, one group received daily IP injection of phenelzine (5 and 10 mg/kg), the second group received 5 mg/kg IP of isocarboxazid, and the third group received vehicle (0.5% methyl cellulose) for 24 days (Period 1 and Period 2). For these periods and 12 days after discontinuing the MAOI treatments (Washout Period), test doses of 5-HT agonists were evaluated for their effects to decrease reinforcements (R) and increase pauses (P). No change in sensitivity to the LSD, Q and TFMPP effects on FR-40 behavior was observed in the vehicle-treated group. However, an attenuated effect of 8-OHDPAT was found in this group. In phenelzine- and isocarboxazid-treated rats the disruption of FR-40 responses by LSD and 8-OHDPAT were significantly reduced during Period 1, Period 2 and Washout Period. A significantly less effect on disruption in FR-40 responses by quipazine and TFMPP during Period 2 and the Washout Period was also seen. Since MAO inhibitors appear to down-regulate both 5-HT1 and 5-HT2 binding sites in brain, the attenuated effects of the 5-HT agonists were anticipated.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacy-initiated implementation of a syringe pump infusion system.

The approach taken by a pharmacy department of a 310-bed community hospital to evaluate and implement a syringe infusion pump system is described. The cost of the minibag system used by the hospital was compared with the cost of the syringe system. A trial of the system involving three medications was implemented in two patient-care areas. After a six-week period, nurses favored expansion of the new system. After a detailed cost comparison was presented to hospital administration, hospitalwide conversion to the new system was approved. Groups of drugs were gradually added to the dispensing list. At the end of a five-month period, 80% of secondary intravenous medications were administered via the new system. Advice is offered to other hospitals considering the system. A smooth transition to a syringe infusion system was the result of the well-planned approach.

Solubility characteristics of diazepam in aqueous admixture solutions: theory and practice.

The solubility of diazepam was investigated to determine compatibility limits for diluting diazepam injection in four large-volume parenteral (LVP) solutions. A solution of diazepam powder (15 mg/ml) in absolute alcohol and of the commercially available diazepam injection (5 mg/ml) were used in the study. Either 1.0 ml of the alcoholic solution or 3.0 ml of the commercial injection were added to 50 ml of the LVPs studied-sterile water for injection (WFI), 5% dextrose injection, 0.9% sodium chloride injection, and lactated Ringer's injection. Diazepam was assayed sprectrophotometrically at 367 nm. The solubility of diazepam in WFI was 0.041 mg/ml after equilibration for 24 hours at 25 degrees C. The solubility of diazepam in the LVPs ranged from 0.04 to 0.05 mg/ml at 25 degrees C. The effects of solution dielectric constants on nonelectrolyte solubility and the minimal fraction of protonated (ionized) diazepam present in typical admixtures are deduced to be negligible determinants of diazepam solubility in i.v. solutions at pH greater than or equal to 5.4 prepared from greater than or equal to 1:10 volume dilutions of diazepam injection. The aqueous solubility data for diazepam corroborate other reported values and are tantamount to recommending against less than a 1:100 volume dilution of diazepam injection when compounding i.v. admixtures.