Effects of body and head positions on bilateral difference in tympanic temperatures

Summary We have examined the nonparallel changes in tampanic membrane temperatures (T _ty) from the two ears in response to various changes in body and head positions. Upon assuming a lateral recumbent position, the T _ty on the lower side increased while that on the upper side decreased. Pressure application over a wide area of the lateral chest only caused inconsistent and obscure asymmetric changes in T _ty. A lateral flexion of the head with the subject sitting upright and a rotation of the head to the side in a supine position induced an increase in the T _ty on the lower side compared to that on the upper side. The temperature and blood flow of the forehead often decreased on the lower side and increased on the upper side, although such responses were not always concomitant with the asymmetric changes in T _ty. A dorsal flexion of the head with the subject in a reclining position caused a slight increase in the T _ty, whereas raising the head upright induced a slight decrease in them. Two additional experiments were carried out with single photon emission computed tomography using ^99mTc-hexamethylpropyleneamine oxime as tracer, and a slight, relative decrease in counts was noted in the right hemisphere during rotation of the head to the right. These results would strongly suggest that unilateral increases and decreases in T _ty could have been caused by one-sided decreases and increases, respectively, in blood flow to the brain and/or the tympanic membrane, induced by a vasomotor reflex involving vestibular stimulation.     

Adenosine A1 receptor-mediated presynaptic inhibition of GABAergic transmission in immature rat hippocampal CA1 neurons

In the mechanically dissociated rat hippocampal CA1 neurons with native presynaptic nerve endings, namely "synaptic bouton" preparation, the purinergic modulation of spontaneous GABAergic miniature inhibitory postsynaptic currents (mIPSCs) was investigated using whole-cell recording mode under the voltage-clamp conditions. In immature neurons, adenosine (10 microM) reversibly decreased GABAergic mIPSC frequency without affecting the mean current amplitude. The inhibitory effect of adenosine transmission was completely blocked by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, 100 nM), a selective Alpha(1) receptor antagonist, and was mimicked by N(6)-cyclopentyladenosine (CPA, 1 microM), a selective Alpha(1) receptor agonist. However, CPA had no effect on GABAergic mIPSC frequency in postnatal 30 day neurons. N-ethylmaleimide (10 microM), a guanosine 5'-triphosphate binding protein uncoupler, and Ca(2+)-free external solution removed the CPA-induced inhibition of mIPSC frequency. K(+) channel blockers, 4-aminopyridine (100 microM) and Ba(2+) (1 mM), had no effect on the inhibitory effect of CPA on GABAergic mIPSC frequency. Stimulation of adenylyl cyclase with forskolin (10 microM) prevented the CPA action on GABAergic mIPSC frequency. Rp-cAMPS (100 microM), a selective PKA inhibitor, also blocked the CPA action. It was concluded that the activation of presynaptic Alpha(1) receptors modulates the probability of spontaneous GABA release via cAMP- and protein kinase A dependent pathway. This Alpha(1) receptor-mediated modulation of GABAergic transmission may play an important role in the regulation of excitability of immature hippocampal CA1 neurons.     

Androgenic modulation of the activity of lumbar neurons involved in the rat bulbocavernosus reflex

The bulbocavernosus (BC) reflex, produced in the BC motor nerve in response to electrical stimulation of the contralateral pudendal sensory nerve, was investigated in intact, castrated, and testosterone-treated castrated male rats under urethane anesthesia. No significant group differences in the reflex latency, sensory or motor conduction velocity, or central delay were observed. A conditioning pulse to the pudendal sensory nerve caused suppression of the averaged antidromic field potential recorded in the contralateral spinal nucleus of the bulbocavernosus (SNB) after stimulation of the SNB axons in the BC motor nerve. The suppression occurred at 6- to 35-ms intervals between shocks to pudendal sensory nerve and BC motor nerve, and was markedly smaller in castrated males than in the other two groups. In contrast, a conditioning pulse to the contralateral BC motor nerve had no effect on the SNB antidromic field potential. These results indicate that androgen modulates the efficacy of synaptic transmission onto SNB motoneurons or other neurons involved in the BC reflex.     

Expression of Functional Molecules in Non-Hodgkin's Lymphoma

It is well known that non Hodgkin's lymphoma (NHL) cells express various antigens which are normally involved in a variety of functions. In addition, NHL is diverse in its proliferative capacity. To investigate the relation between these factors and the clinical picture, 45 cases of NHL were studied by immunohistochemistry using snap-frozen materials obtained before therapy. Reactivities with 27 monoclonal antibodies were examined and the results were correlated with clinical findings. The expression of surface μ and CAM-1 in B-NHLs and CD25 in T-NHLs were significantly associated with bone marrow involvement. B-NHLs without expression of CD21(B2) and T-NHLs with CD25 were seen more frequently in cases with a LDH value of over 500 units/ml. The positivity rate of Ki-67 on B-NHLs was correlated with serum LDH value, NHL histologic classification, and overall survival. These data indicate that immunophenotyping and determination of the proliferative capacity of NHL are of value not only for confirmation of the histopathologic classification of the tumor but also for assessment of clinical behavior.     

A novel translocation involving chromosomes 2, 9, 14, and 22 in chronic myeloid leukemia

A 46-year-old man with chronic myelogenous leukemia was found to have a new complex translocation. In chronic phase, all of the bone marrow cells had a rearrangement of a t(2;9;14;22) (p21;q34;q32;q11). Southern blot analysis of leukocyte DNA revealed rearrangement of the breakpoint cluster region (bcr) within the 5.8-Kb bcr. The patient eventually died in blast crisis 28 months later. The cytogenetic findings of bone marrow cells showed a 46,XY,t(2;9;14;22)(p21;q34;q32;qll),add(lp),del(3q) karyotype in blast crisis.     

Reduced NR2A expression and prolonged decay of NMDA receptor-mediated synaptic current in rat vagal motoneurons following axotomy

To elucidate characteristic changes in the N -methyl- d -aspartate (NMDA) receptor on neurons following axotomy, subunit expressions and functional features of the NMDA receptor were examined in the dorsal motor nucleus of vagus (DMV) of rats receiving vagal axotomy at the neck. Western blotting analysis demonstrated that the expression of NR2A decreased 2–3 days after in vivo axotomy, while expression of NR1 and NR2B, NR2C and NR2D subunits did not change significantly. To examine the functional changes, patch clamp recordings in whole-cell mode were employed on the axotomized DMV neurons identified by retrograde labelling with fluorescent dye. The amplitude ratios of ifenprodil-sensitive components of NMDA response and d , l -2-amino-5-phosphovaleric acid (APV)-sensitive evoked postsynaptic current increased after axotomy. In addition, APV-sensitive postsynaptic currents exhibited a longer decay time in identified axotomized vagal motoneurons than in control neurons. No significant differences in the current density of the NMDA response and the peak amplitude of APV-sensitive synaptic currents were observed between axotomized and intact DMV neurons. In conclusion, a decrease in NR2A expression results in the appearance of functional characteristics of the NMDA receptor predominantly containing the NR2B subunit. This might lead to a long-term increase of the susceptibility of neurons to excitotoxicity.     

A new balloon catheter for selective cerebral perfusion

Selective cerebral perfusion (SCP) is a better method than hypothermic circulatory arrest for brain protection in aortic arch surgery because of fewer time limitations; however; it is more troublesome during surgery. We developed a new catheter for SCP, the SP Stud catheter, with a rib-surface balloon to reduce slipping to eliminate the need for snaring or clamping. To evaluate the slipping resistance of the new catheter, we compared it with two different balloon catheters; a Foley balloon catheter with a smooth-surface balloon as long as the SP Stud catheter, and a Retro-TH catheter with a smooth-surface balloon of discoid shape half as long as the SP Stud catheter. The “draw-strength”, which refers to the slipping resistance, was measured in 20 autopsy carotid arteries in the three groups. The average draw-strengths of SP Stud catheter, foley balloon catheter, and Retro-TH catheter were 92.3±4.0, 20.8 ±1.5, and 17.9±0.8g, respectively, in sclerotic carotid arteries. The SP Stud catheter demonstrated approximately four times more resistance to slipping than the Foley balloon or Retro-TH catheters. The SP Stud catheter demonstrated a higher slipping resistance than conventional catheters, which may allow selective cerebral perfusion without snaring or clamping the carotid arteries, minimize the change of cerebral embolism, and clear the operative field.     

The action of BDNF on GABAA currents changes from potentiating to suppressing during maturation of rat hippocampal CA1 pyramidal neurons

During the development of the hippocampus, the action of GABA shifts from depolarizing to hyperpolarizing, and brain-derived neurotrophic factor (BDNF) has important roles in GABAergic transmission. We demonstrate that BDNF (20 ng ml⁻¹) rapidly and reversibly potentiates postsynaptic GABA_A receptor-mediated currents (by 80.5 ± 14.3 %, n = 10) in hippocampal CA1 pyramidal neurons isolated from postnatal day (P)6 rats, using nystatin-perforated patch-clamp recordings. This potentiation is caused by an elevation of intracellular Ca²⁺ that occurs in response to the activation of Trk B receptor tyrosine kinase and phospholipase C-γ. The modulation of the GABA_A responses by BDNF in hippocampal CA1 pyramidal neurons isolated from P10 rats was more diverse (from potentiating to inhibitory), and at P14, BDNF induced a long-lasting inhibition. In addition, Ca²⁺/calmodulin-dependent protein kinase 2 plays important roles in the potentiating, but not in the inhibitory effect, of BDNF on the GABA_A responses. These results suggest that changes in the intracellular signalling pathway could contribute to the developmental shift of the actions of BDNF on inhibitory systems.     

Venodilator effects of adenosine triphosphate and sodium nitroprusside; Comparisons during controlled hypotension

Adenosine triphosphate as well as sodium nitroprusside has been used for hypotensive anesthesia. The purpose of this study was to examine the possibility that two hypotensive drugs may exert different effects on venous capacitance during controlled hypotension. In rats anesthetized with ketamine, mean arterial pressure was lowered to 50mmHg by intravenous infusion of adenosine triphosphate or sodium nitroprusside. Venous capacitance was assessed before and during induced hypotension by measuring the mean circulatory filling pressure (MCFP). MCFP was measured after briefly arresting the circulation by inflating an indwelling balloon in the right atrium. MCFP was lower during adenosine triphosphate-induced as well as sodium nitroprusside-induced hypotension as compared with the respective value at control (P < 0.01 for adenosine triphosphate and sodium nitroprusside). However, the decrease in MCFP by adenosine triphosphate (0.8 ± 0.1mmHg) was less (P < 0.01) than that by sodium nitroprusside (2.3 ± 0.3mmHg). These results suggest that at a comparable level of arterial hypotension venodilator effect of adenosine triphosphate was less than that of sodium nitroprusside. Less venodilatation during adenosine triphosphate-induced hypotension may contribute to the maintenance of cardiac output during hypotensive anesthesia.(Hoka S, Takeshita A, Aishima K et al.: Venodilator effects of adenosine triphosphate and sodium nitroprusside; comparisons during controlled hypotension. J Anesth 1: 144–147, 1987)     

Long-term Natural Course of the Osteochondral Lesion of the Talus in a Child: A Case Report

Recent reports have described midterm natural courses of osteochondral lesion of the talus (OLT) and lack of progression of ankle osteoarthritis (OA) in adult patients. The relationship between the OLT managed with nonoperative treatment and development of OA in children remains unknown. We report the long-term course of medial OLT in a 12-year-old female who was treated nonoperatively for 10 years. Radiographically, no osteoarthritic changes were observed at the first examination. She initially returned to her basketball club after nonoperative treatment. Although daily activities were not restricted, limitation of recreational activities began to appear at 4 years of follow-up. Subsequently, plain radiographs revealed bone absorption around the osteochondral fragment and osteophyte formation at the medial gutter, then ankle OA was advanced at the final follow-up.