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Information that originates from peripheral sensory organs is conveyed by axons of cephalic sensory cranial ganglia connecting the sensory organs to appropriate central targets in the brain. Thus, the establishment of correct axonal projections by sensory afferents is one of the most important issues in neural development. Previously, we examined the development of the vestibular nerve that originates from the VIIIth ganglion using a flat whole-mount preparation of the rat hindbrain and developed an in vitro, culture preparation that can recapitulate vestibular nerve development (Tashiro, Y., Endo, T., Shirasaki, R., Miyahara, M., Heizmann, C. W. and Murakami, F. (2000) J. Comp. Neurol. 417, 491-500). Both in vivo and in vitro, the ascending branch of the VIIIth ganglion projecting to the cerebellum reaches the base of the cerebellar primordium and starts to splay out towards the rhombic lip, apparently avoiding the ventral metencephalon. We now examine the nature of cues that guide vestibulocerebellar axons by applying various manipulations to the flat whole-mount in vitro preparation. Our observations suggest that local nonpermissive cues and oriented cues play a pivotal role in the guidance of vestibular axons to their central target.

Intracellular recording was made from cat's red nucleus after chronic lesion of the nucleus interpositus (IP) of the cerebellum and the properties of the corticorubral EPSPs were examined. 2. It was found that the time to peak of the corticorubral ESPSs induced from cerebral peduncle (CP EPSP) of chronic cats was much faster than that of normal cats. There was no simple decay following the rapid rise and early summit; instead there was another peak as if the slow normal CP EPSPs were superimposed on the fast ones. 3. By stimulating two loci, sensorimotor cortex and the cerebral peduncle, the conduction velocities of the fibers responsible for the newly appeared fast-rising component of the corticorubral EPSPs were measured. They were almost the same as those of normal corticorubral EPSPs.

Two male infants with congenital hereditary retinoschisis are presented. The disease was detected when they were 11 and 20 months old, respectively, and they were followed up during the subsequent months. Initially, they both revealed a tremendously elevated retinoschisis lesion in both equatorial and peripheral retina, which was associated with foveal retinoschisis. The peripheral ballooning retinoschisis regressed gradually in the following months, and a relatively flat retinoschisis was left. It was proposed that the early stage of the disease is characterized by a bullous retinoschisis followed by its spontaneous regression during the first several years of life. A survey of the literature favors our view.

1. The development of action potential conduction was studied by intracellular recording of antidromic spikes in cat rubrospinal cells. 2. The distance between the C1 and L1 spinal segments increased linearly from 5.6 cm at embryonic day (E) 59 to 9.8 cm at postnatal day (P) 30. 3. The conduction time from the C1 segment to the rubrospinal neuron soma, estimated from antidromic spike latency evoked by stimulation of the C1 segment, decreased rapidly prior to birth and then slowly thereafter. This coincided with a reduction in conduction time variation between cells. 4. The conduction time from the red nucleus to the L1 segment followed a similar time course during development. The conduction time reached the adult value by P30, at which time the spinal cord is only half the adult length. 5. The conduction velocity between the C1 and L1 segments increased monotonically between E59 and P30, from a low of 1 m s‐1 to a maximum of 34 m s‐1. 6. The rise time of rubrospinal neuron somadendritic spikes followed a developmental time course similar to that for conduction time. 7. Myelination of rubrospinal axons, as judged by the presence of myelinated segment spikes, began to occur prior to E59. 8. These findings suggest that development of action potential propagation in rubrospinal cells can be divided into an early and a late stage: conduction time reaches the adult value during the early stage, i.e. by the first postnatal month, and is maintained during the late stage. We propose that myelination, axon diameter increase and maturation of membrane properties act to reduce conduction time to adult values during the early stage, while a proportional increase in fibre diameter with axonal length results in a constant conduction time during the late stage.

The anticlinal nappe which forms the Huon Peninsula and adjacent ranges extends offshore as the Huon Ridge. The frontal thrust of the nappe is the Ramu-Markham Fault (onshore) and a deformation front along the line of the Markham Canyon (offshore). The timing and geometry of the Finisterre arc-continent collision is controversial, and the origin of the Finsch Deep is unresolved.

A south-dipping Subduction system which underlies the Trobriand Trough and 149° Embayment, on the southern margin of the Solomon Sea, is active or was recently active. Oceanic basement is overlain by 2.5 s, two-way travel time (TWTT), of sediment that shows at least two stages of deformation: early thrusts (inner wall) and normal faults (outer wall), and later normal faults that have elevated the outer trench margin. Thrust anticlines and slope basins are developed on the inner wall. The floor of the Solomon Sea Basin arches upward between the Trobriand Trough and the New Britain Trench to form isolated peaks and ridges in the east (152° Peaks) and an east-west Central Ridge in the west. Structures in the subduction system, and in the Solomon Sea Basin, plunge westward towards the point of collision with the New Britain Trench.

The western Solomon Sea is bounded by the Paleogene collision complex of the Papuan Peninsula to the south, and land masses constructed by Cainozoic volcanism to the north and cast. Oblique collision of two trenches in the western Solomon Sea, and concomitant collision of upper plates, have produced structural complexities that may include the local doubling of crustal thickness, coincident with a strong negative gravity anomaly west of 149°E. Lateral flexing of the subducted plate in the New Britain Trench may have caused flexure of the upper plate; this flexure is expressed in the gravity field, faults, dip-slopes, exposure of basement, and alignment of volcanoes.

Abstract:  The pattern of changes in leukocyte counts and the blood concentration of G-CSF were observed in 15 patients undergoing aortocoronary bypass surgery. Myelopoietic function was assessed by examining the myelogram and performing flow cytometry to identify human leukocyte differentiation antigens on bone marrow aspirates obtained from the sternum when opening and closing the sternotomy. The blood concentration of G-CSF increased gradually after removal of the aortic cross clamp and peaked on the first postoperative day (23298 ngml). The white blood cell count also increased during the operation and peaked on the second postoperative day, demonstrating a threefold increase (158002700). Granulocytes represented most of the increase, while lymphocytes and monocytes showed no significant changes. The myelogram showed that the percentages of myeloblasts, promyelocytes, and metamyelocytes did not change; however, the percentage of myelocytes increased significantly during surgery (14.02.5% vs. 17.33.5%, p<0.05). The number of mature myelocytes (LFA-1β and Leu-15 positive) decreased significantly (p<0.01 and p<0.05) during surgery. With the two-color method, the ratio of immature myelocytes (MCS-2 negative and Leu-15 negative) increased significantly (p<0.01). The ratio of myeloblasts (Leu-11 and HLA-DR positive) and the ratio of stem cells (CD 34 and MY-9 positive) did not increase significantly during the operation. G-CSF concentrations increase substantially during aortocoronary bypass surgery and may be responsible for the rise in granulocyte and total leukocyte counts, as well as for the increase in immature myelocytes seen on bone marrow examination.

1.Properties of synaptic transmission during and after repetitive activation of the newly formed cortico-rubral synapses were examined in the red nucleus neurons (RN) of cats after lesions of the nucleus interpositus of the cerebellum (chronic cats) as well as in normal ones.2.A prominent facilitation of the amplitude of cortico-rubral unitary EPSPs was observed in both normal and chronic cats when a stimulus to the cerebral peduncle (CP) was preceded by another stimulus by 2–50 msec.3.Time course of the facilitation shows that it attains maximum at the interval of about 3 msec and decays approximately exponentially lasting for 50 msec or more.4.When three successive stimuli of identical intensity were applied to CP, the degree of facilitation was more prominent than that for double shock.5.There was a positive correlation between the time to peak of the cortico-rubral EPSPs and their maximum value of facilitation.6.The posttetanic potentiation of the cortico-rubral EPSPs was observed after tetanic stimulation to CP in chronic and normal cats. It lasts for a few minutes in both cases.

1.Unitary EPSPs were recorded intracellularly from neurons of the red nucleus (RN) by stimulating the cortico-rubral fibers in normal cats as well as those with chronic lesion of interpositus nucleus (IP) of the cerebellum.2.Two groups of unitary EPSPs were recorded in cats with IP lesion. One consisted of cortico-rubral unitary EPSPs with a shorter time to peak and larger amplitude than those in normal cats. The other consisted of unitary EPSPs of the normal range.3.The appearance of the fast rising group of cortico-rubral EPSPs caused by IP lesions was theoretically predictable based on Rall's compartmental model by assuming that new synapses were formed close to the soma of the RN cells.4.The amplitude of the fast rising EPSPs increased more prominently by hyperpolarizing the membrane potential than that of the slowly rising ones.5.It was concluded that the fast rising group of unitary EPSPs which appeared following IP lesion was due to the formation of new synapses on the proximal portion of the soma-dendritic membrane of RN cell.

Objective: This study compared the cerebral microcirculation during retrograde cerebral perfusion with that during antegrade cardiopulmonary bypass under normothermic and hypothermic conditions. Methods: Brain tissue blood flow was measured with the hydrogen-clearance and colored microsphere (15 and 50 @mm) methods during antegrade cardiopulmonary bypass and retrograde cerebral perfusion. Measurements were performed during normothermia (37^o C), moderate hypothermia (28^o C) and deep hypothermia (20^o C) in groups of mongrel dogs (n = 8). Results: During antegrade cardiopulmonary bypass, the microsphere method showed a significant decrease in cerebral blood flow as body temperature decreased (40.1 +/- 20.8 ml/min/100 gm at 37^o C, 16.2 +/- 18.0 ml/min/100 gm at 20^o C with 50 @mm microspheres) At 20^o C, the cerebral blood flow measured with the 15 @mm microspheres was significantly lower than that assessed with the hydrogen-clearance method (11.3 +/- 7.0 vs 24.8 +/- 7.0 ml/min/100 gm). During retrograde cerebral perfusion, the microsphere method also showed a significant decrease in cerebral blood flow with cooling. At 37^o C, the cerebral blood flow measured with the 15 @mm microspheres (0.8 +/- 0.7 mI/min/100 gm) was significantly lower than that assessed with the hydrogen-clearance method (10.1 +/- 3.5 ml/min/100 gm). At both 28^o and 20^o C, the hydrogen-clearance method showed significantly higher cerebral blood flow (10.1 +/- 5.8 and 8.2 +/- 3.7 ml/min/100 gm) than did the 50 @mm microspheres (1.8 +/- 0.6 and 1.0 +/- 0.8 ml/min/100 gm) and 15 @mm microspheres (0.23 +/- 0.14 and 0.18 +/- 0.15 ml/min/100 gm). Conclusion: (1) Cerebral blood flow that shunts to capillaries is increased during antegrade cardiopulmonary bypass under deep hypothermia. (2) During retrograde perfusion, the majority of the blood flow shunts away from brain capillaries, even under normothermic conditions, and blood flow through large venoarterial shunts increases as body temperature decreases, Although the cerebral microcirculation during retrograde perfusion is decreased, retrograde perfusion provides some degree of oxygenation to the body. (J Thorac Cardiovasc Surg 1997;114:440-7)

Afterhyperpolarization (AHP) following single or short trains of spikes in rubrospinal neurones (RN neurones) of the cat has been studied with intracellular recording techniques. The AHP amplitude was potential dependent; it increased with depolarization and decreased with hyperpolarization and had an extrapolated reversal potential about 20 mV below resting membrane potential. The AHP was associated with an increase in the membrane conductance and it was concluded that the AHP is primarily caused by an increase in membrane conductance to potassium ions. The time course of the conductance change underlying the AHP was measured with short current pulses and calculated from the AHP voltage. The AHP following a single spike was conditioned at different interspike intervals by a preceding spike (or several spikes). In many RN neurones the AHP (conductance) following a spike added approximately linear to that generated by a preceding spike. In most cells, however, the AHP following a spike was instead depressed by a preceding spike. The summation of AHPs increased progressively, while the depression appeared to be already maximal with one preceding spike. The depression was then approximately constant for interspike intervals less than the AHP duration. It will be shown in a following paper that these properties of the AHP are reflected in the behaviour of the repetitive discharge evoked by constant current pulses in the same neurones.

Membrane electrical constants have been studied in neurons of the red nucleus (RN) of the cat which were identified antidromically from the spinal cord. For each cell, the input resistance was determined from the membrane potential changes to current steps and was found to be 2.5 ± 0.9 MO in twenty five RN cells studied. In addition, linear summation of the membrane responses induced by two current pulses was demonstrated.2.From the membrane voltage transients to current steps, the first membrane time constant, t0, and second time contant, t1, were determined as 5.6 ±1.0 msec and 0.6 ± 0.2 msec, respectively. The ratio of the amplitudes of two exponential functions, E1/E0, was 0.18 ± 0.05. A linear relation was found between the ratio of these amplitudes of exponential functions and that of the two time constants.3.The cable parameter (electrotonic length, L) of the combined soma and dendrites of the RN neurons was estimated as 1.1 from membrane transient data using the relation developed by Rall (1969).4.By using this parameter, an attempt was made to estimate the location of the two excitatory inputs on the soma-dendritic membrane of RN cells.

The alkaline ferricyanide and the Park-Johnson's methods were studied in order to determine glucose oligomers separated by liquid chromatography in nanomole quantities. In the alkaline ferricyanide method, high sensitivity was obtained by measuring ultraviolet absorbance of the reduced reagents. The presence of some kinds of salts or alcohols did not affect the colour development of the reagents. The applicability of the present measuring system to an automatic sugar analyzer has been demonstrated by examining several glucose oligomers.