Naloxone-reversible analgesia produced by microstimulation of the arcuate nucleus of the hypothalamus in pentobarbital-anesthetized rats

Suppression of the tail flick response to noxious heat and paw withdrawal response to noxious pressure were produced by electrical stimulation of arcuate nucleus of the hypothalamus (ARH) in pentobarbital anesthetized rats. Systemic administration of naloxone (2 mg/kg) greatly antagonized the ARH stimulation-produced inhibition of both algesic reflexes. The thresholds of stimulation for inhibition of two spinal nociceptive reflexes in the lightly anesthetized state were not significantly different from the thresholds of stimulation at the same ARH sites in the awake state in the same animals. These findings provide evidence establishing the (1) usefulness of the anesthetized rat model for investigation of antinociceptive mechanisms; (2) the involvement of endogenous opioid mechanisms in mediating ARH stimulation-produced analgesia.

Chronotropic Effect of the Methanolic Extracts of the Plants of the Paris Species and Steroidal Glycosides Isolated from P. vietnamensis on Spontaneous Beating of Myocardial Cells1

Rhizomes of five identified plants of the PARIS species, Liliaceae, and Rhizoma Paridis which are sold as a crude drug named "Zao Xiu", "Qiyeyizhihua" or other names in nine different markets in China were tested for their effects on cultured cardiomyocytes. In the standard medium, eight methanol extracts out of sixteen at a concentration of 0.2 mg/ml stopped the spontaneous beating of myocardial cell sheets, but these extracts significantly increased the beating rate when the concentration was reduced to one half. In the culture medium with a low calcium concentration, 0.5 mM, the beating rate of the cells decreased to about 60% of that of the control in the standard medium. The addition of five of the extracts to the low calcium medium at a concentration of 0.1 mg/ml caused a stop of cell beating, but the other extracts increased beating rate at least by 10%. Three steroidal glycosides isolated from the rhizomes of P. VIETNAMENSIS (Takht.) H. Li also stimulated cell beating. Among them, diosgenin-3- O-alpha- L-rhamnopyranosyl-(1-->2) - (alpha- L-arabinofuranosyl-(1-->4))- D-glucopranoside (compound 1) was the most effective stimulant for cell beating as well as calcium uptake by the myocardial cells.

Multipoint linkage mapping of the Xq25-q26 region in a family affected by the X-linked lymphoproliferative syndrome

We have performed, in a large Swiss family, a study of linkage between various DNA markers in the Xq24-27 region and the locus for the X-linked lymphoproliferative syndrome (XLP). Our results indicated that the marker DXS37 in Xq25-q26 is genetically linked to the XLP syndrome. The multipoint linkage analysis showed that the disease locus is distal to DXS11, but proximal to the hypoxanthine phosphoribosyl-transferase gene (HPRT).

[Experimental studies on the significance of processing Eucommia ulmoides Oliv]

The inhibitory action on isolated uterus of middle-pregnancy mice have been compared in Eucommia ulmoides and its salt water processed product. It has been found that after processing the inhibitory action on the automatic contraction of isolated uterus, the antagonism on spasmodis contraction caused by acetylcholine are increased, but the antagonism on spasmodis contraction caused by pituitarium posterius and the Pb content are decreased.

Clinical value of N-myc oncogene amplification in 52 patients with neuroblastoma included in recent therapeutic protocols

Southern blot analysis of neuroblastoma (NB) cell DNA from 52 patients (58 samples) allowed the detection of an N-myc amplification on three of the 13 BM samples and three of 13 tumor samples at diagnosis, on two of 17 tumor samples taken after induction therapy, on three of seven BM samples and two of the five local tumor samples taken after relapse. N-myc was amplified in two of the 15 patients with stage I to III NB and in 10 of the 36 patients with stage IV neuroblastoma over 1 year of age. Conclusions from the analysis are as follows: first tumor samples obtained on previously treated patients are histologically modified and detection of N-myc amplification is not accurate; consequently N-myc amplification must be defined at diagnosis. Surgical biopsies of the primary tumors can, however, be delayed and malignant cells obtained by ultrasound-guided punctures or analyzed on bone marrow samples if they represent more than 50% of the total population. Second, any attempt to define the prognostic value must be performed on a group of patients treated with a new aggressive protocol of chemotherapy; it will require a multiparametric analysis including, in particular, results of an extensive clinical staging at diagnosis and histological criteria.

[Comparison of some trace element contents of Eucommia ulmoides Oliv. and its processed products]

A comparison of the contents of 7 trace elements (Zn, Mn, Cu, Fe, Ca, P, Pb) in Eucommia ulmoides and its processed products has been made, and the significance of processing Eucommia ulmoides is discussed in light of the experimental results.

Permeability of the mitochondrial outer membrane to organic cations

Inhibition of mitochondrial respiration by hydrophobic fluorescent dyes (Rhodamine 6G, Safranine O, Pyronine B) is much less potentiated by digitonin-lysis of the outer membrane than that by polyamines or adriamycin. This situation may be explained by impermeability of the anion-selective channels in the outer mitochondrial membrane to large cations and by the ability of hydrophobic (but not polar or amphipathic) ions to directly permeate lipid bilayers.

Characterization of a phospholipase A2 in hamster lung and in vitro and in vivo effects of bleomycin on this enzyme

Phospholipase A2 (PLA2) activity from adult hamster lung was characterized using L-alpha-1-palmitoyl-2-arachidonyl-[arachidonyl-1-14C]-phosphatidylcholine as the substrate. The released [14C]-arachidonic acid was separated by TLC. The enzyme activity increased with increasing incubation time (0-120 minutes), calcium ion concentration (0-25.0 mM) and protein (0-2.0 mg). The optimum pH was 8.0. Deoxycholate had a concentration dependent (0.1 to 0.5 mM) inhibitory effect on the activity. PLA2 specific activity was the highest in mitochondrial fraction. PLA2 activity following incubation with bleomycin was increased in a dose related fashion. In vivo study showed that both PLA2 activity and collagen content in hamster lung were significantly elevated at 14 days followed intratracheal instillation of bleomycin. The activation of PLA2 may play an important role in bleomycin-induced pulmonary toxicity.

High dose-rate afterloading in the treatment of cervical cancer of the uterus

From January 1981 to December 1983, 380 patients with cervical carcinoma of uterus were treated with high dose-rate intracavitary afterloading therapy (Ralstron-20B) and 60Co external irradiation. All of these cases have been followed over 3-5 years. The 5-year survival rates for Stages I, II, III, and IV were 100%, 81.5%, 73.9%, and 0% respectively. The over all 5-year survival rate was 79.1%. The results were comparable to that of conventional radium therapy in 1980 (5-year survival rate for radium group: Stage I 50%, Stage II 72.2%, Stage III 52.2%, Stage IV 0%). The moderate and severe rectal reactions in this series were 11.8% and 1.6% (radium group moderate 6.0%, severe 2.2%), which were higher than that of radium group. The incidence of bladder reaction was 7.1%. The problems of high dose-rate intracavitary therapy and the combination therapy with intracavitary and external irradiation are discussed in this paper.

Inhibition of baroreflex following microinjection of GABA or morphine into the nucleus tractus solitarii in rabbits

The possibility that putative transmitters may influence the aortic nerve stimulation-produced bradycardia and depressor responses was examined in urethane- and chloralose-anesthetized, paralyzed and artificially ventilated rabbits. The ipsilateral microinjection of gamma-aminobutyric acid (GABA, 2-4 micrograms) or morphine hydrochloride (2-4 micrograms) into the nucleus tractus solitarii (NTS) area could partially block the evoked bradycardia and depressor responses produced by stimulation of the aortic nerve without influencing the basal blood pressure and heart rate. This blocking effect of either GABA or morphine was dose-related. Pretreatment with GABA receptor antagonist bicuculline methiodide (0.15-0.20 micrograms) and opiate receptor antagonist naloxone hydrochloride (1-2 micrograms) into the same medullary area completely abolished the effect of GABA and morphine, respectively. Application of bicuculline also greatly antagonized the effect of morphine, but the blocking effect of GABA on the evoked bradycardia and depressor responses still existed following the pretreatment of naloxone. These results indicate that GABAergic and opiate systems present at the NTS exert an inhibitory influence on the evoked baroreflexes and inhibitory effect of the latter may be related to the activation of GABAergic receptor in this nucleus.

Stimulation of the ventrolateral medulla inhibits the baroreceptor input to the nucleus tractus solitarius

Extracellular recording experiments were done in urethane- and chloralose-anaesthetized, paralyzed and artificially ventilated rabbits. Thirty-one baroreceptor-sensitive neurones were identified in the region of the nucleus tractus solitarius (NTS) by their excitatory responses to stimulation of the ipsilateral aortic nerve. A conditioning stimulus delivered to the ipsilateral or contralateral rostral ventrolateral medulla (rVLM) inhibited the excitatory responses of 80.0% (19 out of 24) neurones to an aortic test stimulus as early as 3 ms and extending as long as 400 ms after conditioning. The same inhibitory effect was also observed by application of excitant amino acid DL-homocysteic acid (0.2 M, 100 nl) into the ipsi- or contralateral rVLM area in 6 units. In 5 units inhibited by rVLM stimulation, evoked discharges were inhibited by prolonged electrical stimulation of the superficial peroneal nerve (SP) with low intensity and low frequency (0.1-0.3 mA and 5-10 Hz). These results provide the electrophysiological evidence for the suppressing effect of the rVLM on the excitatory responses of NTS neurones to baroreceptor afferent stimulation.

Interactions between Escherichia coli arginyl-tRNA synthetase and its substrates

Interactions between Escherichia coli arginyl-tRNA synthetase and its substrates were extensively studied and distinctly demonstrated. Various approaches such as equilibrium dialysis, fluorescence titration, and substrate protection against heat inactivation of the enzyme were used for these studies. In the absence of other substrates, the equilibrium dissociation constants for arginine, ATP, and the cognate tRNA were about 70 microM, 0.85 mM, and 0.45 microM, respectively, at pH 7.5, in Tris buffer. The binding of arginine to the enzyme was affected neither by the presence of tRNA nor by the presence of ATP but was considerably enhanced when ATP and tRNA were both present at saturating concentrations. The dissociation constant in this case (about 16 microM) was very close to the Km (12 microM) for arginine during aminoacylation. The binding of ATP (the equilibrium dissociation constant KD approximately 0.85 mM) was not affected by the presence of arginine but was depressed in the presence of tRNA (KD became 3 mM). Arginyl-tRNA showed a dissociation constant of (4-5) X 10(-7) M which was not affected by the presence of a single other substrate. Possible explanations for the high Km for tRNA in the aminoacylation are discussed. Our results indicated pronounced interactions between substrates mediated by the enzyme under catalytic conditions. Periodate oxidation did not alter the tRNA binding to the enzyme. The oxidized tRNA still afforded protection against heat inactivation of the enzyme.