Anionic polymerization of fluorine-containing vinyl monomers, 6. Polymerizations of fluoroalkyl acrylates and methacrylates initiated by organoaluminium compounds

The anionic polymerizations of 2,2,2-trifluoroethyl acrylate ( 1a ), 2,2,2-trifluoroethyl methacrylate ( 1b ), 2,2,2-trifluoro-1-trifluoromethylethyl acrylate ( 2a ), and 2,2,2-trifluoro-1-trifluoromethylethyl methacrylate ( 2b ) were examined with triethylaluminium and diethylaluminium active methylene chelate compounds as initiators. 2b was polymerized with triethylaluminium. Diethyl(ethyl cyanoacetato)aluminium was found to produce polymers of 1a and 1b . Diethyl(acetylacetonato)aluminium and diethyl (dimethyl malonato)aluminium, however, show low reactivity towards these four monomers. The resulting polymers show unimodal molecular weight distribution with number-average molecular weights of 10⁴?10⁵, measured by GPC. The initiation reaction and the copolymerization reactivity with styrene support the anionic polymerization mechanism.     

Quantitative distribution of rat brain monoamine oxidase A by [14C]clorgyline autoradiography

The distribution of functionally active monoamine oxidase type A (MAO-A) was investigated by in vivo quantitative autoradiography using [¹⁴C]clorgyline in normal, conscious rat brain. [¹⁴C]clorgyline was synthesized by the methylation reaction of N-desmethylclorgyline using [¹⁴C]methyliodide. Sixty minutes after [¹⁴C]clorgyline administration (1.58 MBq/animal i.v.), the brains were removed and prepared for autoradiography by washing the brain sections with 5% trichloroacetic acid solution to remove the nonbinding free tracer. The amount of MAO-A was calculated from the regional acid-insoluble tissue radioactivity and the specific activity of the tracer. The highest amount of MAO-A (5.84 nmol/g tissue) was found in the locus coeruleus. The interpeduncular nucleus, habenular nucleus, fasciculus retroflexus, and solitary tract nucleus possessed over 1.6 nmol/g tissue of MAO-A. Among 23 regions of interest, the lowest amount of MAO-A (0.37 nmol/g tissue) was found in the globus pallidus. The findings of this study suggest that the pattern of MAO-A parallels both in neuroanatomical distribution and in density that of norepinephrine and serotonin innervation. The MAO-A concentration was, however, relatively low in the dopamine-related areas. This corresponded to the previous results obtained by histochemical analysis. In addition, among the white matter structures, a high amount of MAO-A was found specifically in the fasciculus retroflexus.     

Effects of ATP antagonists on purinoceptor-operated inward currents in rat phaeochromocytoma cells

The effects of suramin, reactive blue 2 (RB2) and d-tubocurarine (d-TC) were investigated electrophysiologically to elucidate the mechanisms underlying their antagonism of P₂ purinoceptor-mediated responses. All three compounds inhibited an adenosine triphosphate (ATP)-activated inward current in rat phaeochromocytoma PC12 cells in a concentration-dependent manner. The order of potency was RB2 > suramin > d-TC. The inhibition induced by suramin or RB2 was reversible, whereas that induced by d-TC was not reversed after a 5-min rinse. The inactivation of the ATP-activated current was accelerated by d-TC but not by suramin or RB2. RB2 administered simultaneously with ATP exerted much weaker inhibition compared to that induced by prior administration, suggesting that RB2 is a slowly acting antagonist. This was not observed for suramin or d-TC. Suramin and RB2 caused a parallel shift in the concentration/response curve for the ATP-activated current. With d-TC the maximal response of ATP was decreased but the concentration producing half-maximal response was unchanged. The voltage dependency of the ATP-activated current showed less inward rectification in the presence of d-TC. Suramin or RB2 did not affect the voltage dependency. These results suggest that suramin and RB2 reversibly block binding of ATP to receptors, whereas d-TC blocks ion permeability through the ATP-activated channel.     

Membrane potential changes in vocal cord tensor motoneurons during breathing, vocalization, coughing and swallowing in decerebrate cats

We studied the patterns of membrane potential changes in vocal cord tensor motoneurons, i.e. cricothyroid muscle motoneurons (CTMs), during fictive breathing, vocalization, coughing, and swallowing in decerebrate paralyzed cats to determine the nature of central drives to CTMs during these behaviors. CTMs were identified by antidromic activation from the superior laryngeal nerve. During breathing, CTMs always depolarized during the inspiratory phase, and sometimes depolarized during the expiratory phase as well. During vocalization, CTMs strongly depolarized. During coughing, CTMs exhibited depolarizations during both inspiratory and expiratory phases, but it was interrupted by a transient repolarization between the last part of the inspiratory phase and the first part of the abdominal burst during which chloride-dependent inhibitory postsynaptic potentials were revealed. During swallowing, most CTMs hyperpolarized, and this hyperpolarization was sometimes followed by a weak depolarization. We conclude that the main role of the cricothyroid muscle is vocalization but the functional roles in coughing and swallowing are minor, and that the CTM activity during resting breathing and vocalization are primarily controlled by excitatory inputs, while during coughing and swallowing, inhibitory inputs play roles in shaping membrane potential trajectories.     

The restorative effect of naps on perceptual deterioration

Human performance on visual texture discrimination tasks improves slowly (over days) in the absence of additional training. This 'slow learning' requires nocturnal sleep after training and is limited to the region of visual space in which training occurred. Here, we tested human subjects four times in one day and found that with repeated, within-day testing, perceptual thresholds actually increased progressively across the four test sessions. This performance deterioration was prevented either by shifting the target stimuli to an untrained region of visual space or by having the subjects take a mid-day nap between the second and third sessions.     

Imagery Vividness Affects Habituation Rate

In order to investigate the effect of individual differences in imagery vividness on habituation rate, 14 subjects were threatened with receiving and then imagined receiving an electric shock. Subjects first habituated to a tone which was then used as an auditory signal for the shock threat and the imagined shock. The skin conductance response (SCR) was used to follow the course of habituation. Results demonstrated that subjects with non-vivid imagery habituated to the tone more rapidly than subjects with vivid imagery when the tone was associated with imagining an electric shock. Implications of this finding for therapeutic techniques using instructed imagery are discussed.     

Roles of Department of Clinical Laboratory in infection control

The Department of Clinical Laboratory plays an important role in the hospital and has much information about patients and pathogens. Laboratory data are essential to support clinical physicians who diagnose and treat patients. For nosocomial infections, laboratory-based surveillance is recognized as essential to confirm outbreaks. Therefore, the role of the Department of Clinical Laboratory is very important in infection control. In Tohoku University Hospital, we have an Infection Control Unit located in the Department of Clinical Laboratory. The core role of the Infection Control Unit is diagnosis, treatment and preventative healthcare associated with infections. The Infection Control Team (ICT) performs rounds in the hospital (The ICT members are ICN, ICD, a microbiological technologist and a dietician), consultations about clinical cases, infection control, and organize the regional infection control network, "Miyagi Infection Control Network". The ICT rounds are performed once a week in two wards, and two times a year for one ward. The consultations are an important role of the ICD, and concern clinical infection cases and infection control in our hospital and the other regional hospitals, and produce advice on appropriate clinical information. The regional network is important for the collection of information about the pathogens and the susceptibility of antimicrobial agents in the region. "Miyagi Infection Control Network" has held a forum 5 times a year from 1999, and 300-400 healthcare workers join the forum and discuss infection control.     

Appearance of prolactin-releasing peptide-producing neurons in the area postrema of adrenalectomized rats

Prolactin-releasing peptide (PrRP) was found to be a novel hypothalamic peptide that stimulates prolactin release in vitro and in vivo. In the normal adult rat brain, PrRP neurons are known to be located in only three areas, i.e. the dorsomedial hypothalamic nucleus, ventrolateral reticular formation; and nucleus of the tractus solitarius in the medulla oblongata. These PrRP neurons project neurites into various brain areas, including regions such as the paraventricular nucleus, supraoptic nucleus, and bed nucleus of the stria terminalis. Both PrRP nerve fibers and a high level of PrRP receptor, UHR-1, mRNA are observed in the area postrema (AP),but no PrRP neurons are detected in the AP of normal rats. In this study, we clearly demonstrated that PrRP-producing cells newly appeared in the AP of adrenalectomized rats by in situ hybridization and immunocytochemistry. Our results suggest that PrRP may have some important roles in the AP of adrenalectomized rats. This is the first report demonstrating the appearance of PrRP-positive cells in the AP.     

Hormone therapy and affect

This study investigated the influence of hormone therapy on affect in a double blind crossover trial. The sample consisted of 49 women who had previously undergone hysterectomy and bilateral oophorectomy. Therapy consisted of 3 mth each of ethinyl oestradiol — 50 μg/day, levonorgestrel — 250 μg/day, “Nordial” — a combination of these two substances, and placebo. Affect was measured by the Hamilton Depression Rating Scale, verbal reports by women and self-ratings on visual analogue scales. Ethinyl oestradiol was found to have a beneficial influence on aspects of affect such as Hamilton scores, anxiety, irritability and insomnia.

The influence of hormones on Hamilton scores could be partly but not fully explained by the alleviation of hot flushes. Norgestrel showed less favourable changes initially but these tended to diminish by the third therapy month. Most of the women studied were not clinically depressed. Anxiety symptoms were the major features exhibited in the group of women investigated. The results of this study suggest that visual analogue rating scales are of questionable validity in assessing affect in patients without any appreciable psychiatric morbidity.     

Pancreatic endocrine tumours associated with WDHA syndrome

Summary Nine pancreatic endocrine tumours of patients with watery diarrhoea hypokalaemia achlorhydria (WDHA) syndrome were examined by immunohistochemistry and electron microscopy. All cases revealed neoplastic proliferation of VIP (vasoactive intestinal peptide)-immunoreactive (IR) cells. Immunoreactivity to a novel peptide hormone PHM-27, which is processed from a common big precursor peptide of VIP (prepro VIP/PHM-27), was identified in VIP-IR cells of 8 tumours. VIP-PHM-IR cells had secretory granules measuring about 130 to 220 nm in diameter. Radioimmunoassay of tumour tissue extracts showed high VIP and PHM contents in proportional amounts in most cases. According to the results of immunostaining, the 8 tumours fell into two large groups; 5 with PP (pancreatic polypeptide)-IR cells and 3 with CT (calcitonin)-IR cells. The former group demonstrated VIP cells and PP cells intermingled in various proportions, including one tumour in which coexistence of PP-IR and VIP-IR in the same cells was demonstrated. Cell heterogeneity of the tumours and possible relationships of VIP, PP and CT cells were discussed.This work was supported in part by Grants-in-Aid for Cancer Research from the Ministry of Health and Welfare and from the Ministry of Education, Science and Culture, Japan