Night shift paralysis

Summary 12% of night nurses surveyed claimed to have suffered from a totally incapacitating paralysis that may be related to sleep paralysis, and contribute to impaired levels of safety on the night shift. The incidence of this paralysis is shown to be age-related, largely confined to the early hours of the morning, and to increase over consecutive night shifts.Acknowledgments. We wish to dedicate this paper to Professor Dr Günther Hildebrandt, Director of the Institut für Arbeitsphysiologie und Rehabilitationsforschung, University of Marburg/Lahn in honor of his 60th birthday. We also wish to thank the Nursing Officers and nurses concerned for their help in this study.     

Diurnal rhythm of hemocyte population in an insect,Schizodactylus monstrosus Drury

Summary InSchizodactylus monstrosus the total hemocyte count appeared to be much lower during the day than at night. At night, the percentage of prohemocytes and spherule cells increased substantially over that of granular hemocytes, plasmatocytes and adipohemocytes. The percentage of sessile hemocytes was much higher during the day. Hemogram rhythmicity was much affected in decapitated insects; altered photoperiod had little effect on it.     

Paralysies révélatrices de la leucémie de Gross chez le rat

Summary Inoculation of Wistar CF rats with Gross virus induces in 86% of the animals a leukaemia which is associated, in nearly 50% of the cases, with a paralysis of the hind legs.This paralysis is due to the compression of the spinal cord by leukaemic cell infiltrates which develop in the lumbar area. No neurotropic virus has been found in these animals.     

Effects of chronic paralysis of chick embryo by flaxedil on the development of the neuromuscular junction]

Chronic paralysis of Chick embryos by the cholinergic antagonist flaxedil blocks the subsynaptic accumulation of acetylcholinesterase but not the formation of acetylcholine receptor cluster. Flaxedil paralysis also causes an increase of the total muscle content of acetylcholine receptor without altering the half-life of the receptor protein. The spontaneous activity of the embryon therefore "shuts off" the synthesis of extrasynpatic acetylcholine receptor.     

Defining the role of post-synaptic α-neurotoxins in paralysis due to snake envenoming in humans

Snake venom α-neurotoxins potently inhibit rodent nicotinic acetylcholine receptors (nAChRs), but their activity on human receptors and their role in human paralysis from snakebite remain unclear. We demonstrate that two short-chain α-neurotoxins (SαNTx) functionally inhibit human muscle-type nAChR, but are markedly more reversible than against rat receptors. In contrast, two long-chain α-neurotoxins (LαNTx) show no species differences in potency or reversibility. Mutant studies identified two key residues accounting for this. Proteomic and clinical data suggest that paralysis in human snakebites is not associated with SαNTx, but with LαNTx, such as in cobras. Neuromuscular blockade produced by both subclasses of α-neurotoxins was reversed by antivenom in rat nerve–muscle preparations, supporting its effectiveness in human post-synaptic paralysis.     

Comparison of diurnal and nocturnal rates of 5-hydroxytryptamine turnover in the rat mediobasal hypothalamus

Rates of 5-hydroxytryptamine (5-HT) turnover in the mediobasal hypothalamus of male rats were estimated using pharmacological methods during the daytime and at night. Concentrations of 5-HT in this hypothalamic area were higher nocturnally than diurnally; this was apparently due to increased 5-HT synthesis and decreased 5-HT catabolism at night.     

Studies on the etiology of the experimental neuropathy from industrial adhesive (glues)

Chickens treated by paintbrushing with glue distillate (used in shoe industries), hydrocarbon mixture and TOCP in hexane, developed paralysis (4/5); in these, we have demonstrated a diffuse degeneration of the myelinic sheath of the peripheral and central neurites. Besides TOCP, cyclohexane (because of its higher concentration in the glue distillate and in the hydrocarbon mixture) may be indicated as responsible for occupational neuropathy.     

Action of serotonin on neuromuscular transmission in normal guinea pigs and those treated with paralyzing doses of botulinum toxin type A]

Serotonin inhibits the muscular contractions elicited by indirect stimulation; injected before Botulinum toxin it prevents the paralysis induced by this toxin.     

Comparison of diurnal and nocturnal rates of 5-hydroxytryptamine turnover in the rat mediobasal hypothalamus

Summary Rates of 5-hydroxytryptamine (5-HT) turnover in the mediobasal hypothalamus of male rats were estimated using pharmacological methods during the daytime and at night. Concentrations of 5-HT in this hypothalamic area were higher nocturnally than diurnally; this was apparently due to increased 5-HT synthesis and decreased 5-HT catabolism at night.Supported by NIH grant RR07187 (TSK) and NIH grant HD10202 (Neuroendocrine Core).     

Why do patients with respiratory muscle paralysis require artificial hyperventilation?

Summary The primary reason for the need of hyperventilation in patients with respiratory paralysis is the insufficiency of the inhibitory Hering-Breuer reflex. The artificial distension of the lungs with normal tidal volume cannot inhibit the respiratory centre in contrast to the normal state.     

Night pineal N-acetyltransferase activity in rats exposed to white or red light pulses of various intensity and duration

Summary Night N-acetyltransferase activity is suppressed by red and white light; the red light intensity, however, must be 10 times higher. Short light pulses also suppress night N-acetyltransferase; the higher the light intensity, the shorter the pulse is effective.The authors are grateful to Mrs Marie Svobodová for her skillful technical assistance.     

Why do patients with respiratory muscle paralysis require artificial hyperventilation?

The primary reason for the need of hyperventilation in patients with respiratory paralysis is the insufficiency of the inhibitory Hering-Breuer reflex. The artificial distension of the lungs with normal tidal volume cannot inhibit the respiratory centre in contrast to the normal state.     

Maturation of the pineal melatonin rhythm in long- and short-day reared Djungarian hamsters

Male Djungarian hamsters, reared under long (16L/8D) or short (10L/14D) days, were sacrificed at various ages during the day or night, or at night following a 30-min light pulse. The pineal melatonin rhythm matured similarly under long and short days by 20 days of age. The results are discussed in context of the hypothesis that melatonin mediates the photoperiod effects which forestall puberty in short-day reared hamsters.     

Maturation of the pineal melatonin rhythm in long- and short-day reared Djungarian hamsters

Summary Male Djungarian hamsters, reared under long (16L/8D) or short (10L/14D) days, were sacrificed at various ages during the day or night, or at night following a 30-min light pulse. The pineal melatonin rhythm matured similarly under long and short days by 20 days of age. The results are discussed in context of the hypothesis that melatonin mediates the photoperiod effects which forestall puberty in short-day reared hamsters.Supported by NIH research grant HD-05481.     

Experimental allergic encephalomyelitis in T-lymphocyte deficient rats.

Thymectomized, lethally irradiated rats reconstituted with syngeneic bone marrow were injected with rat brain in complete Freund adjuvant mixture. Both, they and sham-thymectomized, irradiated and bone marrow protected rats displayed a higher incidence of leg paralysis than normal non-irradiated animals. Thymectomy lowered the incidence of the disease.     

Induction of autotomy in the American bird grasshopperSchistocerca americana (Drury) by the ecdysone agonist RH-5849 and investigation of its mode of action

The non-steroidal ecdysone agonist RH-5849 (1,2-dibenzoyl-l-tert-butylhydrazine) was found to be an effective neurotoxicant on injection into the American bird grasshopper,Schistocerca americana (Drury). Treated grasshoppers became immediately hyperactive, followed by loss of coordination, paralysis and eventually death. We also discovered that this compound induced bilateral autotomy of the metathoracic legs during the early stages of intoxication. However, no evidence of ecdysonergic or morphogenetic activities was observed. Synergism studies with neurotoxins of known mode of action suggested that RH-5849 has a mechanism of action similar to that of 4-amino pyridine, which blocks potassium channels.     

Der Atmungsquotient der Tabakblätter

Summary The respiration quotient (R Q) of the tobacco leaves is always higher than one. In contrast to that of the leaves of succulent plants it does not drop below unity during the night. From this it is concluded that the organic acids (malic, oxalic and citric acids), which serve as respiration substrate, cannot be related to the carbohydrate metabolism (tricarbon acid cycle). They must rather be considered as primary assimilation products or as related to the nitrogen metabolism (transamination of the primary assimilation product aspartic acid).     

Energy metabolism,respiration frequency and O2-consumption per breathing act in 11 different sunbird species during day and night

Summary The mean metabolic rates of 11 sunbird species are in the expected range based on data from other birds. Nevertheless the difference between day and night levels is greater (58–69%) than normal. Breathing frequencies among these birds correspond more closely to the (higher) levels found in empirical data for mammals. O₂-consumption per breathing act remains nearly constant during day and night indicating that the diurnal cycle of O₂-consumption is regulated mainly by modulation of breathing frequencies, which correlate directly with gaseous metabolism.     

Experimental allergic encephalomyelitis in T-lymphocyte deficient rats

Summary Thymectomized, lethally irradiated rats reconstituted with syngeneic bone marrow were injected with rat brain in complete Freund adjuvant mixture. Both, they and sham-thymectomized, irradiated and bone marrow protected rats displayed a higher incidence of leg paralysis than normal non-irradiated animals. Thymectomy lowered the incidence of the disease.Supported by the Research Fund of Croatia (Zagreb).     

Studies on the etiology of the experimental neuropathy from industrial adhesive (glues)

Summary Chickens treated by paintbrushing with glue distillate (used in shoe industries), hydrocarbon mixture and TOCP in hexane, developed paralysis (4/5); in these, we have demonstrated a diffuse degeneration of the myelinic sheath of the peripheral and central neurites. Besides TOCP, cyclohexane (because of its higher concentration in the glue distillate and in the hydrocarbon mixture) may be indicated as responsible for occupational neuropathy.Acknowledgments. The authors thank Prof. G. Azzali, Director of the Institute of Human Anatomy University of Parma (Italy), for his interpretations of microscopic ultrastructural aspects.Istituto di Anatomia Umana Normale.Istituto di Clinica Neurologica.Istituto di Chimica Organica.