PubMed Health⌕ Search

Biomedical subjects

M Hisada

Publications and source records attributed to M Hisada.

At least 55 records · Page 3Linked to original sources
PubMed1993

Intersegmental ascending interneurons controlling uropod movements of the crayfish Procambarus clarkii.

The premotor effects of intersegmental ascending interneurons upon uropod motor neurones in the crayfish Procambarus clarkii (Girard) are examined with intracellular recording and staining techniques. We show that many ascending interneurones can affect the activity of the antagonistic opener and closer motor neurones in the terminal ganglion. Based upon soma position, ascending interneurones are divided into three groups of rostral, medial, and caudal interneurones. Twenty-four ascending interneurones are characterized physiologically according to their inputs from the tailfan and their output effects on the uropod motor neurones of both sides. Each interneurone is identifiable as a unique individual by means of overall shape, soma position, number of main branches, the commissure in which primary neurites cross the midline, axon position in the 5th-6th abdominal connective and physiological responses. They are classified into six classes; coactivating, coinhibiting, reciprocally closing, reciprocally opening, variably effective, and not effective interneurones, according to their premotor effects on the uropod motor neurones. These ascending interneurones seem to act as multifunctional units conveying sensory information from the tailfan to the anterior abdominal ganglia and, at the same time, influencing the uropod motor pattern in the terminal abdominal ganglion.

Animals↗
PubMed1992

Local spiking interneurons controlling the equilibrium response in the crayfish Procambarus clarkii.

1. In the crayfish brain, the responses of local spiking interneurons to body roll simulated by bending of statocyst hairs, were investigated with intracellular recording and staining techniques. The neurons had two separate branching portions in the protocerebrum and the deutocerebrum. They were named as type-I local neurons and further classified into 5 types (ac-U, vplc-U, vplc-B, vupc-U, vupc-B). 2. Vupc-U neurons showed excitatory responses and vplc-U neurons showed inhibitory responses to inward hair deflection of the statocyst ipsilateral to their deutocerebral branches. The other 3 types were of mixed populations of the interneurons showing either excitatory or inhibitory responses to the stimulation. 3. Of 10 type-I local neurons showing excitatory responses to inward hair deflection, 6 interneurons had output effects on oculomotor and/or descending neurons. All these 6 interneurons showed large EPSPs and much higher frequency of spikes to the hair stimulation than those of the other 4. All 8 type-I local neurons that showed inhibitory responses had no output effects. 4. Type-I local neurons controlled two equilibrium responses, compensatory eye movement and righting reflex, either simultaneously or independently.

Acoustic Stimulation↗
PubMed1992

[Postoperative infection control in patients with hepatic, biliary tract, and pancreatic cancers].

Postoperative infection occurs more frequently in patients with malignant disease than in patients with benign disease. Postoperative infection control in patients with hepatic cancer, biliary tract cancer and pancreatic cancer is studied. Although in patients with jaundice due to malignancy the rate of positive bacterial culture of the bile collected at the time of PTCD was low, the rate of positive bile culture increased after 10 to 14 days of PTCD. The predominant strain was Enterococcus spp., followed by Klebsiella spp., Enterobacter spp. and E. coli in that order. These bacteria isolated from the bile were considered to be causative organisms of postoperative infection. Prophylactic antibiotics after the operation for jaundice due to malignancy should be chosen based on the results of bile culture. In patients undergoing hepatectomy, which is considered to be an aseptic operation, gram positive cocci such as S. aureus was the most frequently encountered organism. On the other hand, in patients undergoing hepatectomy and intestinal anastomosis, enteric bacteria were frequently isolated from the infectious foci. In this study there were 6 cases of methicillin-resistant S. aureus (MRSA) postoperative infection, 3 cases after pancreatoduodenectomy, and 3 cases after hepatectomy. Even after an aseptic operation, postoperative MRSA infection is likely to occur in patients undergoing a more invasive operation, so hospital infection control should be again emphasized.

Bacteria↗
PubMed1991

Effects of glutathione depletion on the synthesis of proteoglycan and collagen in cultured chondrocytes.

We studied the effect of the depletion of glutathione on the synthesis of proteoglycan and collagen in cultured chick chondrocytes. When the cultured chondrocytes were incubated with 1 mM buthionine sulfoximine (BSO), a specific inhibitor of gamma-glutamyl-cysteine synthetase, the intracellular glutathione level markedly dropped within 12 h with no loss of cell viability. Incorporation of 35SO2-4 into proteoglycan was lowered in the presence of BSO. When the 35S-labeled proteoglycans were separated into two fractions by glycerol density gradient centrifugation, the inhibitory effect of BSO on the synthesis of proteoglycan was greater in the fast-sedimenting proteoglycan fraction, which consisted mainly of cartilage specific large proteoglycan (PG-H), than in the slowly sedimenting proteoglycan fraction. The inhibition by BSO of the synthesis of core protein-free glycosaminoglycan chains primed by p-nitrophenyl-beta-D-xyloside was smaller than the inhibition of the synthesis of proteoglycan. Analysis of glycosaminoglycans labeled with [3H]glucosamine indicated that the treatment of chondrocytes with BSO resulted in a small increase in the proportion of synthesis of hyaluronic acid to the synthesis of total glycosaminoglycan. The incorporation of [3H]proline into collagen was also inhibited by BSO. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of the 3H-labeled collagen showed that, in the presence of BSO, processing of Type II collagen appeared to slow down and the proportion of Type X collagen synthesis was reduced.

Animals↗
PubMed1990

Chronic immune thrombocytopenia in sarcoidosis.

We report a 69 year-old female with sarcoidosis who developed chronic thrombocytopenia, a rare complication of this disorder. Histologically normal bone marrow with increased number of megakaryocytes and high level of PAIgG strongly suggest the immune destruction of platelets as the cause of thrombocytopenia. In addition to thrombocytopenia, this case is also distinctive in its clinical manifestation. The patient developed several infrequent manifestations of sarcoidosis including complete AV block, uveitis, skin eruptions and middle lobe syndrome, but, did not have an intrathoracic adenopathy, the commonest manifestation of this disease.

Aged↗
PubMed1989

The paraneuronal nature of neurons: nonspiking communication in the crayfish central nervous system.

We have found a large portion of the neurons in the abdominal ganglia of the crayfish, Procambarus clarkii (Girard) to be local nonspiking neurons. These neurons are anaxonic, have extensive arborizations of neurites and have their entire structure confined within a single ganglion. They show relatively low membrane potentials of 40-50 mV and under no circumstance generate action potentials, yet their membrane potential changes can effectively modulate the activity of postsynaptic neurons which are generally motoneurons. The transmission is chemical and transmitter release in many, if not all, of them is continuous even at their "resting" level. Electron microscope examination showed an extensive intermingled distribution of both input and output synaptic structures. This synaptic distribution together with the passive electric property suggests that individual neurites of this type of neurons function rather independently, constituting numerous local circuits. Similar nonspiking communication is also found among the ordinary "spiking" motoneurons, indicating that this mode of communication is far more widely used in the crayfish central nervous system than generally believed. These findings appear to necessitate a radical revision of our understanding of how the central nervous system operates in arthropods.

Animals↗
PubMed1987

Opposing parallel connections through crayfish local nonspiking interneurons.

Unilateral local nonspiking interneurons in the terminal (sixth) abdominal ganglion of crayfish (Procambarus clarkii Girard) can be classified into two major groups of PL and AL types by their gross morphology and somatic position. These premotor interneurons are the neural components of uropod motor pattern formation. They receive sensory input from the exopodite of the contralateral side as well as that of the ipsilateral side. Small fluctuations in their membrane potentials cause sustained change in activity of the motoneurons innervating the uropod muscles. PL interneurons, which make noninverting connections to an identified closer, the reductor motoneuron No. 1, mainly receive excitatory input from the afferents of the contralateral exopodite, whereas inverting PL interneurons receive inhibitory input. AL interneurons receive distinctly different input from the afferents. Noninverting AL interneurons mainly receive inhibitory input, whereas inverting AL interneurons receive excitatory input. The rate of discharge of the reductor motoneurons is increased by sensory stimulation. The PL interneurons form either excitatory or disinhibitory pathways, which are relevant in function to the observed increase of the motoneuron. Conversely, the AL interneurons form either inhibitory or disfacilitatory pathways. Thus, the PL and the AL interneurons are fractionated in function and distinguishable in terms of their physiology by their input and output correlations. Functional meaning of the presence of these two types of unilateral local nonspiking interneurons of opposing connections in the uropod motor control system is discussed.

Afferent Pathways↗
PubMed1987

Neuronal structure and synaptic distribution of a uropod closer motor neuron in the crayfish terminal ganglion.

One of the uropod closer muscles in the crayfish, the adductor exopodite, is innervated by two large identified motor neurons. They were injected intracellularly with horseradish peroxidase or nickel chloride to reveal the structure and distribution of the input and output synapses using electron microscopy. The development of nickel with rubeanic acid greatly improved the tissue preservation at the ultrastructural level compared with ammonium sulphide. Cell bodies of the motor neurons lying in the ventro-lateral cortex of the ganglion are extensively invaginated by glial cells. Input synapses occur directly upon the primary neurite within the neuropil or upon the major anterior neurite. They are most abundant, however, upon the numerous smaller neurites of the motor neuron. The primary neurite in the dorsal region of the neuropil, upon which no synapses were made, is wrapped with glial cells. Occasionally, these two adductor exopodite motor neurons were found as adjacent postsynaptic profiles at the same synapse when both cells were stained simultaneously in the same preparation. In the present study we could not locate any sites of synaptic output which strictly fulfil the structural criteria of a synapse on the processes of the motor neuron. This result is inconsistent with physiological evidence which suggests that spikeless interactions occur between the two adductor exopodite motor neurons and their synergists. This might be the result of two possible features of the interaction: the sites of synaptic output may be limited to a few restricted branches, and the interaction between these motor neurons may depend largely upon electrical synapses.

Animals↗
PubMed1986

Distribution and ultrastructure of synapses on a premotor local nonspiking interneuron of the crayfish.

Many premotor local nonspiking interneurons are involved in the control of the uropod movements of a crayfish. One of these interneurons was impaled intracellularly, characterized physiologically, and then labeled by intracellular horseradish peroxidase (HRP) injection to examine the distribution and ultrastructure of synapses. Depolarization of this interneuron by a current injection excited the closer motoneurons of the uropod and inhibited its opener motoneurons, but hyperpolarization had no effect. Input and output synapses are distributed all over the major branches and the finer neurites except for the main neurite (7-10 micron in diameter), which runs near the dorsal surface of the neuropil. Both types of synapse are located on the same neurite and are often intermingled in close proximity, often less than 1 micron apart. Presynaptic terminals of the interneuron contain round, clear vesicles that are densely packed in fine branches and spines. The number of synaptic vesicles associated with a particular output synapse was estimated to be about 2,000. No dense-cored granules are observed in the labeled neurites. Our results support the proposal that synaptic transmission in this class of interneurons of the crayfish can sometimes be restricted to a very small region of the branches and that, therefore, different regions of the interneuron can function independently.

Animals↗
PubMed1986

Regional specialization in synaptic input and output in an identified local nonspiking interneuron of the crayfish revealed by light and electron microscopy.

Lateral inhibition of several mechanosensory interneurons in the crayfish terminal ganglion is mediated by a pair of identified local nonspiking interneurons called local directionally selective (LDS) interneurons. The ultrastructure and synaptic distribution of these interneurons were investigated by using intracellular labeling with horseradish peroxidase for electron microscopy. The LDS interneuron has bilateral, asymmetric arborizations. They are connected by a thick transverse neurite on which no synapses are made. The neurites on the side ipsilateral to the cell body are smooth and receive almost entirely input synapses. On the other hand, the contralateral neurites have prominent numerous swellings or varicosities from which many short fine spines arise, with intermingled input and output synapses. Both synapses, however, are not always associated with varicosities and spines. Presynaptic neurites of the LDS interneuron contain only round agranular synaptic vesicles in the vicinity of synaptic specializations. These morphological findings correlate well with the physiology of this interneuron: it is functionally polarized to receive input on one side (ipsilateral to the cell body) of the ganglion and convey it to the other side.

Afferent Pathways↗
PubMed1986

Sustained membrane potential change of uropod motor neurons during the fictive abdominal posture movement in crayfish.

The occurrence of the uropod steering response as one of the equilibrium reflexes to body rolling in crayfish is significantly facilitated if the stimulus is given while the animal is performing the abdominal posture movement. This facilitation of the descending statocyst pathway by the abdominal posture system takes place between the uropod motor neurons and the statocyst interneurons, which directly project from the brain to the terminal abdominal ganglion where the motor neurons originate. To elucidate the synaptic mechanisms underlying the postural facilitation of the steering response, we analyzed in this study the activity of an identified set of uropod motor neurons during the fictive abdominal extension movement in the whole-animal preparation. Intracellular recordings from the dendritic branches of uropod motor neurons revealed that they were continuously excited during the fictive abdominal extension. The large fast motor neurons usually showed a sustained depolarization of the subthreshold magnitude. The small slow ones showed a suprathreshold sustained depolarization with spikes superimposed. Putative inhibitory motor neurons, on the other hand, showed a sustained hyperpolarization with their spontaneous spike discharge suppressed. The discrete synaptic potentials could hardly be distinguished and, instead, small fluctuations of the membrane potential were observed during the sustained depolarization of both the fast and slow motor neurons. Occasionally, large discrete synaptic potentials could be observed to be superimposed on the sustained depolarization. The occurring frequency of these synaptic potentials showed, however, no significant increase associated with the sustained depolarization. It hence seemed unlikely that these potentials were responsible for producing the sustained depolarization. Their amplitude during the sustained depolarization was smaller than that observed during the quiescent state. The sustained membrane potential change during the fictive abdominal movement was also observed in many neurons other than motor neurons, including local nonspiking interneurons and mechanosensory spiking interneurons. Both motor neurons and interneurons showed a decrease in their membrane resistance during the sustained membrane potential change. We concluded that the sustained depolarization of uropod motor neurons during the fictive abdominal extension was produced by the summation of small chemically transmitted postsynaptic potentials.(ABSTRACT TRUNCATED AT 400 WORDS)

Abdomen↗
PubMed1986

Local nonspiking interneurons involved in gating of the descending motor pathway in crayfish.

Uropod motor neurons in the terminal abdominal ganglion of crayfish are continuously excited during the abdominal posture movement so that subthreshold excitatory postsynaptic potentials from the descending statocyst pathway can elicit spike activity in the motor neurons only while the abdominal posture system is in operation. Local nonspiking interneurons in the terminal ganglion were also found to show sustained membrane potential change during the fictive abdominal posture movement. Artificial membrane potential change of these interneurons by intracellular current injection in the same direction as that actually observed during the abdominal movement caused similar excitation of uropod motor neurons. Artificial cancellation of the membrane potential change of these interneurons during the abdominal movement also caused cancellation of the excitation of uropod motor neurons. We concluded that the continuous excitation of uropod motor neurons during the fictive abdominal movement was mediated, at least partly, by the local nonspiking interneurons. Fourteen (36%) out of 39 examined nonspiking interneurons were judged to be involved in the excitation of uropod motor neurons during the fictive abdominal movement. Another 25 interneurons (64%) were found not to be involved in the excitation of motor neurons, although most of them had a strong effect on the uropod motor neuron activity when their membrane potential was changed artificially. The interneurons that were involved in the excitation of motor neurons during the abdominal movement included both of the two major structural types of nonspiking interneurons in the terminal ganglion, i.e., those in the anterolateral portion and those in the posterolateral portion. No strict correlation was found between the structure of nonspiking interneurons and their function in the control of uropod motor neuron activity.

Abdomen↗
PubMed1986

Behavioral transition of crayfish avoidance reaction in response to uropod stimulation.

Unilateral mechanical stimulation of a uropod elicited an avoidance reaction in the crayfish Procambarus clarkii. Depending upon the animal's size, either one of two alternative behavioral acts emerged as the avoidance reaction to similar stimuli. A stationary resting posture of the crayfish and a passive extension of the abdomen were prerequisite conditions for inducing the avoidance reaction. In small animals (less than 10 cm in body length), the "dart" response was mainly elicited. Animals responded with a sudden closing of both uropods and rapid forward walking to scuttle away from the stimulus source. This act was regarded as one form of escape behavior. With increasing animal size, the "turn" response became more probable than the "dart" response. During the "turn" response, the uropod on the stimulated side opened and that on the contralateral side closed. This act was frequently followed by a rapid turning movement towards the stimulus source with an extension or flexion of the abdomen. This act was also regarded as a variant form of defensive behavior. In large animals with autotomized chelipeds, the response to the uropod stimulation reverted to that of the "dart" response after 2 to 3 days.

Adaptation, Biological↗
PubMed1984

The effects of some putative transmitters and biogenic amines on uropod abductor muscle in the crayfish Procambarus clarkii and Cambaroides japonicus.

The effects of some putative transmitters and biogenic amines were examined on the uropod ventral abductor exopodite (AbdExV) muscle in two crayfish species Procambarus clarkii and Cambaroides japonicus. Bath application of L-glutamate to the AbdExV muscle caused sustained contract while gamma-aminobutyric acid (GABA) depressed the nerve-evoked contraction of the muscle. Acetylcholine (ACh) had no effect on both the resting tension and the nerve-evoked contraction. Iontophoresis of L-glutamate and GABA onto the surface of the muscle fiber further confirmed that glutamate and GABA are the possible excitatory and inhibitory transmitters respectively at the neuromuscular junction of AbdExV muscle. Bath application of 5-hydroxytryptamine (5-HT) and octopamine (Oct) caused enhancement of the nerve-evoked contraction but dopamine (DA) had no effect on both the resting tension and the nerve-evoked contraction.

Action Potentials↗