Effect of activated sweat glands on the intensity-dependent sweating response to sustained static exercise in mildly heated humans

Changes in the number of activated sweat glands (ASGs) and sweat output per gland (SGO) with increased exercise intensity during sustained static exercise were investigated. Fourteen male subjects performed 20, 35, and 50% maximal voluntary contraction (MVC) for 60 s with the right hand (exercised arm) at an ambient temperature of 35 degrees C and 50% relative humidity. Although sublingual, local skin, and mean skin temperatures remained essentially constant throughout the exercise at each intensity, the sweating rate (SR) of nonglabrous skin on the nonexercised left forearm increased significantly with a rise in exercise intensity (p<0.05). Changes in the number of ASGs with rising exercise intensity paralleled changes in the SR, but the SGO did not change markedly with altered exercise intensity. These results suggest that in mildly heated humans, at less than 50% MVC, the increase in the SR from nonglabrous skin with rising exercise intensity during sustained static exercise is dependent on changes in the number of ASGs and not on SGO.     

A comparative study of the JAM test and 51Cr-release assay to assess the cytotoxicity of dendritic cells on hematopoietic tumor cells

Dendritic cells (DCs) are potent antigen presenting cells and possess a direct anti-tumor cytotoxic ability. Nevertheless, the mechanism of anti-tumor cytotoxicity by DCs and the methods for its evaluation are not fully elucidated. In order to clarify this mechanism of cytotoxicity, we examined the ability of DCs 1) to suppress [³H] thymidine (³H-TdR) uptake by tumor cells; 2) to induce cytolysis on ⁵¹Cr-labeled tumor cells; 3) and to induce DNA fragmentation on ³H-TdR labeled tumor cells (JAM test). Cytolysis and DNA fragmentation are markers of necrotic and apoptotic mechanisms of cytotoxicity in vitro, respectively. DCs inhibited approximately 38.6% to 54.8% of the growth of B4D6, NB4, U937, and Daudi cells as evaluated by the uptake of ³H-TdR. However no cytolysis was verified by ⁵¹Cr-release assay. On the other hand, cytotoxicity rates found using the JAM test ranged from 3 to 81% depending on the cell line and the effector to target cell ratio. The discrepancy of cytotoxicity between ⁵¹Cr-release assay and the JAM test may be due to the phagocytosis of apoptotic tumor cells or the absorption of released ⁵¹Cr by DCs surrounding the target cells. In conclusion, the JAM test was more sensitive than the 4-h and the 10-h ⁵¹Cr-release assay to investigate cytotoxicity mediated by DCs toward hematopoietic tumor cell lines in vitro.     

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.