甘氨双唑钠对鼻咽癌移植瘤的时辰放射增敏作用

目的 观察甘氨双唑钠（CMNa）联合时辰放疗对鼻咽癌祼鼠移植瘤的时辰放射增敏作用,并探讨其作用机制.方法 将荷瘤裸鼠随机分为3组：放疗组、放疗＋CMNa组、空白对照组,每组分3HALO（光照后小时,hours after light onset）、9HALO、15HALO、21HALO四个时辰进行相应处理.测定肿瘤再生长延长时间（regrowth delay time,TGD）,绘制生长曲线.用免疫组化法检测各组肿瘤标本中HIF-1α、γ-H2AX和凋亡蛋白的表达.结果 通过对各组TGD的比较.以放疗＋CMNa组对肿瘤的抑制效果最好.在该组中,TGD：15HALO＞21HALO＞9HALO＞3HALO,15HALO与3HALO的TGD比较有统计学意义 15HALO与3HALO的HIF-1α、γ-H2AX及凋亡蛋白的表达水平比较有统计学意义.结论 甘氨双唑钠联合时辰放疗对鼻咽癌裸鼠移植瘤有明显的时辰放射增敏作用,以15HALO放疗＋CMNa组对肿瘤的抑制效果最佳.其机制可能与HIF-1α的表达.DNA双链损伤,凋亡有关.     

Testosterone derivatives are neuroprotective agents in experimental diabetic neuropathy

In this study we have assessed the effect of testosterone (T), dihydrotestosterone (DHT) and 5αandrostan-3α, 17β-diol (3α-diol) therapies on diabetic neuropathy. Diabetes was induced in adult male rats by the injection of streptozotocin and resulted in decreased T and increased 3α-diol levels in plasma and in decreased levels of pregnenolone and DHT in the sciatic nerve. Moreover, a reduced expression of the enzyme converting Tinto DHT (i.e., the 5α-reductase) also occurs at the level of sciatic nerve, suggesting that the decrease of DHT levels could be due to an impairment of this enzyme. Chronic treatment for 1 month with DHT or 3α-diol increased tail nerve conduction velocity and partially counteracted the increase of thermal threshold induced by diabetes. Treatment with DHT increased tibial Na⁺,K⁺-ATPase activity and the expression of myelin protein P0 in the sciatic nerve.DHT, 3α-diol and T reversed the reduction of intra-epidermal nerve fiber density induced by diabetes. These observations indicate that T metabolites can reverse behavioral, neurophysiological, morphological and biochemical alterations induced by peripheral diabetic neuropathy. I. Roglio, R. Bianchi: These authors contributed equally to this study. Received 4 January 2007; received after revision 13 February 2007; accepted 27 March 2007     

Role of grafted Schwann cells in the regeneration of intraspinal nerve fibers when peripheral nerve, skeletal muscle or submandibular gland fragments are transplanted into the spinal cord of the mouse

Small pieces of peripheral nerve, skeletal muscle or submandibular gland, taken from young or new-born mice, were grafted into the non-transected spinal cord of young albino mice, at the thoracic level, through a punctiform meningeal opening. Neighbouring intraspinal nerve fibres, severed during the grafting process, regenerate into and eventually throughout the transplants. In this regenerative process, sedentary or migrating Schwann cells of the transplants probably have a prominent influence in guiding the growth of the axonal sprouts they ensheathe and eventually myelinate.     

Reduction of efferent renal nerve activity by propranolol in rabbits]

During intravenous infusion of propranolol (0.3--0.8 mg/kg) in the Rabbit, systolic arterial pressure is decreased (-6.5 +/- 4.2 mmHg) and electrical activity recorded from central end of the renal nerve is reduced significantly (-8.7 +/- 14.-%) with regard to the activity obtained, at the same pressure levels, by hemorrhage (+7.9 +/- 6.4%; p less than 0.25) or by intravenous infusion of the peripheral vasodilator sodium nitroprusside (+14.1 +/- 9.9%; p less than 0.01).     

Increased demyelination and axonal damage in metallothionein I+II-deficient mice during experimental autoimmune encephalomyelitis

Metallothioneins I+II (MT-I+II) are antioxidant, neuroprotective factors. We previously showed that MT-I+II deficiency during experimental autoimmune encephalomyelitis (EAE) leads to increased disease incidence and clinical symptoms. Moreover, the inflammatory response of macrophages and T cells, oxidative stress, and apoptotic cell death during EAE were increased by MT-I+II deficiency. We now show for the first time that demyelination and axonal damage are significantly increased in MT-I+II deficient mice during EAE. Furthermore, oligodendroglial regeneration, growth cone formation, and tissue repair including expression of trophic factors were significantly reduced in MT-I+II-deficient mice during EAE. Accordingly, MT-I+II have protective and regenerative roles in the brain. Received 31 October 2002; received after revision 23 November 2002; accepted 26 November 2002 RID="*" ID="*"Corresponding author. M. Penkowa and C. Espejo contributed equally to this paper.     

17β-estradiol in vitro affects Na-dependent and depolarization-induced Ca2+ transport in rat brain synaptosomes

Effects of 17-estradiol (E₂) in vitro on Na-dependent Ca²⁺ efflux from, and depolarization-induced Ca²⁺ uptake into, the nerve cell were studied with the use of synaptosomes isolated from the brain stem, mesencephalic reticular formation (MRF), caudate nucleus and the hippocampus of long-term ovariectomized adult female rats. It was found that E₂ (1) at a concentration of 10 nM or lower, stimulates Na-dependent Ca²⁺ efflux in the caudate nucleus and hippocampus, and does not affect the efflux in MRF and brain stem; (2) at concentrations above 10 nM has no effect on the Ca²⁺ efflux in any of the four structures investigated; and (3) produces a biphasic effect on the depolarization-induced Ca²⁺ uptake, increasing it in all structures except MRF at 10 nM concentration, and decreasing it at concentrations higher than 10 nM, irrespective of the structure investigated. These results suggest that E₂, acting at extranuclear sites, modulates synaptic transmission via alterations of Ca²⁺ transport mechanisms in nerve endings.     

The possible involvement of protein kinase C and phospholipase A2 inHydra tentacle regeneration

The participation of protein kinase C (PKC) in the regeneration of tentacles ofHydra vulgaris was studied. Regeneration was induced by 1,2-sn-dioctanoyl-glycerol (diC₈) and the novel diterpenoidic diacylglycerol verrucosin B (VB), a potent PKC activator extracted from marine sources. VB substantially increasedHydra average tentacle number (ATN) at concentrations 10,000 times lower than those needed for diC₈ to exert an analogous effect. When both synthetic and natural VB analogues were tested, the structure/activity relationship found inHydra tentacle regeneration was identical to that known for DAG-induced activation of PKC in vitro. VB-induced increase of ATN was strongly counteracted by the PKC inhibitors sphingosine and A3, but was not synergic with a tenfold increase of extracellular Ca²⁺ concentration or with an increase of intracellular Ca²⁺ concentration obtained either with the ionophore A23187 or with thapsigargin. This suggested the involvement of a non-Ca²⁺-dependent PKC in VB-triggeredHydra tentacle regeneration. The involvement of phospholipase A₂ (PLA₂) activation inHydra regenerative processes was studied using the novel site-specific inhibitor of the enzyme, oleyloxyethylphosphorylcholine (OOPC), which brought about a striking inhibition of ATN in the low molar range. This effect was reversed by arachidonic acid (AA), while an enhancement of ATN was also observed with an inhibitor of AA uptake from membrane phospholipids, thus suggesting that PLA₂-catalysed liberation of AA is involved inHydra tentacle regeneration. OOPC also blocked verrucosin B-induced PKC-mediated enhancement of ATN, thus suggesting that this effect is also mediated by PLA₂ activation. ATN was increased also by compound 48/80, a direct activator of pertussis toxin-sensitive GTP-binding proteins, and this effect was counteracted by pertussis toxin pretreatment. None of the known AA cascade inhibitors exhibited an effect on ATN comparable to that exerted by OOPC, but, surprisingly, the cycloxygenase inhibitor indomethacin strongly enhanced ATN, thus suggesting that prostanoids might effect a negative control onHydra regenerative processes. This represents the first attempt so far reported to study the implication of more than one biochemical pathway as a signalling event in the hydroid regenerative processes.     

Peripheral erythrocyte levels, hemolysis and three vanadium compounds

Three vanadium compounds of different valence states were administered to adult mice. Two, four, and eight days following treatment of vanadium, cardiac blood was collected. The blood sample was used to ascertain the peripheral erythrocyte count (cell/mm3) and to determine the in vitro hemolytic index of erythrocytes obtained from mice treated in vivo with either the tri-, tetra-, or pentavalent vanadium compound. Data indicate that the tetravalent form was the most effective test substance in 1) promoting rupture of isolated erythrocytes compared to red cells retrieved from control mice and 2) depressing the erythrocyte count obtained from heart blood; maximum effects were manifest four days post-treatment. For all treatments there appeared to be a good correlation between the degree of vanadium-induced hemolysis and the peripheral erythrocyte count reduction following exposure to the vanadium.     

Peripheral erythrocyte levels,hemolysis and three vanadium compounds

Summary Three vanadium compounds of different valence states were administered to adult mice. Two, four, and eight days following treatment of vanadium, cardiac blood was collected. The blood sample was used to ascertain the peripheral erythrocyte count (cell/mm³) and to determine the in vitro hemolytic index of erythrocytes obtained from mice treated in vivo with either the tri-, tetra- or pentavalent vanadium compound. Data indicate that the tetravalent form was the most effective test substance in 1) promoting rupture of isolated erythrocytes compared to red cells retrieved from control mice and 2) depressing the erythrocyte count obtained from heart blood; maximum effects were manifest four days post-treatment. For all treatments there appeared to be a good correlation between the degree of vanadium-induced hemolysis and the peripheral erythrocyte count reduction following exposure to the vanadium.     

Transport,verteilung und Metabolismus von3H-und14C-markiertem DDT in graviden mäusen unter hungerbelastung

Summary After i.p. application of 1, 0,5 and 0,1 mg p,p' DDT, labelled with³H or¹⁴C, to pregnant mice in different stages of pregnancy, the same level of radioactivity was found in the fetal and maternal blood. Starvation for 2 days caused a significant increase of residues, especially in the liver. Residue levels of DDT and its metabolities DDE, DDD, DCB and (DDOH+DDA) are found in fetal and maternal blood, brain liver and fat.     

Anatomical evidence for cross regeneration of motor axons in a cockroach

Summary The technique of electrophoretic application of intracellular markers is used to demonstrate that motor axons can regenerate into the contralateral limb of a cockroach after the nerve has been crossed to the contralateral side.Supported by NIH grants IRO1NS1420401 and 5KO4NS0014102.     

Rejection of worm load through singly and repeatedly sensitized peritoneal exudate cells during experimental ancylostomiasis

Sensitized peritoneal exudate cells from Swiss albino mice donors infected with a single dose of 1000 A. caninum larvae could expel a challenge dose of 500 larvae from recipients at a faster rate when compared to cells from repeatedly infected (250 + 250 + 500) donors. However, at 36 h after challenge, the larval expulsion was almost the same in both the groups. Because of the bowel sensitization by the cells, some larvae (not expelled) in the 1st group, readily migrated into muscles where they met allergic immobilization and death due to infiltration of inflammatory cells and their exudates at these sites.     

Blockage of the NLRP3 inflammasome by MCC950 improves anti-tumor immune responses in head and neck squamous cell carcinoma

The NLRP3 inflammasome is a critical innate immune pathway responsible for producing active interleukin (IL)-1β, which is associated with tumor development and immunity. However, the mechanisms regulating the inflammatory microenvironment, tumorigenesis and tumor immunity are unclear. Herein, we show that the NLRP3 inflammasome was over-expressed in human HNSCC tissues and that the IL-1β concentration was increased in the peripheral blood of HNSCC patients. Additionally, elevated NLRP3 inflammasome levels were detected in tumor tissues of Tgfbr1/Pten 2cKO HNSCC mice, and elevated IL-1β levels were detected in the peripheral blood serum, spleen, draining lymph nodes and tumor tissues. Blocking NLRP3 inflammasome activation using MCC950 remarkably reduced IL-1β production in an HNSCC mouse model and reduced the numbers of myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs) and tumor-associated macrophages (TAMs). Moreover, inhibiting NLRP3 inflammasome activation increased the numbers of CD4⁺ and CD8⁺ T cells in HNSCC mice. Notably, the numbers of exhausted PD-1⁺ and Tim3⁺ T cells were significantly reduced. A human HNSCC tissue microarray showed that NLRP3 inflammasome expression was correlated with the expression of CD8 and CD4, the Treg marker Foxp3, the MDSC markers CD11b and CD33, and the TAM markers CD68 and CD163, PD-1 and Tim3. Overall, our results demonstrate that the NLRP3 inflammasome/IL-1β pathway promotes tumorigenesis in HNSCC and inactivation of this pathway delays tumor growth, accompanied by decreased immunosuppressive cell accumulation and an increased number of effector T cells. Thus, inhibition of the tumor microenvironment through the NLRP3 inflammasome/IL-1β pathway may provide a novel approach for HNSCC therapy.     

Zur Leberregeneration der Ratte nach Teilhepatektomie während akuter CCl4-Intoxikation

Summary Following 2/3 hepatectomy + CCl₄, the labelling- (³H-thymidine) and mitosis-index of liver epithelia increases 8 h later than after an unique 2/3 hepatectomy, and the peak of compensatory regeneration is reached 16 h later. Then the curve declines and 48 h post operationem reparative regeneration due to CCl₄ necrosises starts.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.     

CD95-mediated cell signaling in cancer: mutations and post-translational modulations

Apoptosis has emerged as a fundamental process important in tissue homeostasis, immune response, and during development. CD95 (also known as Fas), a member of the tumor necrosis factor receptor (TNF-R) superfamily, has been initially cloned as a death receptor. Its cognate ligand, CD95L, is mainly found at the plasma membrane of activated T-lymphocytes and natural killer cells where it contributes to the elimination of transformed and infected cells. According to its implication in the immune homeostasis and immune surveillance, and since several malignant cells of various histological origins exhibit loss-of-function mutations, which cause resistance towards the CD95-mediated apoptotic signal, CD95 has been classified as a tumor suppressor gene. Nevertheless, this assumption has been recently challenged, as in certain pathophysiological contexts, CD95 engagement transmits non-apoptotic signals that promote inflammation, carcinogenesis or liver/peripheral nerve regeneration. The focus of this review is to discuss these apparent contradictions of the known function(s) of CD95.     

Experimental catalepsy: Influences of cholinergic transmission in restraint-induced catalepsy

Summary Possible cholinergic mechanisms in experimental catalepsy were evaluated by using the pinch-induced model in mice. In control, saline-injected mice, the median number of attempts needed to achieve a criterion level of catalepsy was 6. All 3 dose levels of physostigmine reduced this median to about 2 trials; neostigmine did not significantly reduce the number of trials. Opposite effects were obtained with atropine, with which all 3 doses tested increased the number of trials needed to cause catalepsy, and at the higher doses (5 and 10 mg/kg) most of the mice (80%) became insusceptible; atropine methyl bromide had no such effects. Thus, this kind of catalepsy may be mediated by cholinergic mechanisms that are central and not peripheral.     

Binding of estradiol to synaptosomal mitochondria: physiological significance

The subsynaptosomal distribution and specific binding of 17beta-estradiol in vitro to mitochondria isolated from presynaptic nerve endings of female rat brain were examined. 17Beta-estradiol is (i) distributed unequally in synaptosomes and mitochondria posses the highest capacity to bind estradiol with respect to the available amount of the hormone. (ii) Estradiol binds specifically to isolated synaptosomal mitochondria. A Michaelis-Menten plot of specific binding was sigmoidal within a concentration range of 0.1-5 nM of added estradiol, with a saturation plateau at 3 nM. Binding of higher estradiol concentrations demonstrated an exponential Michaelis-Menten plot, indicating non-specific binding to mitochondria. Vmax and Km for the sigmoidal-shape range were estimated as 46 +/- 6 fmol of estradiol/mg of mitochondrial proteins and 0.46 +/- 0.07 nM free estradiol respectively. (iii) Estradiol binding is not affected by the removal of ovaries. The results show that inhibition of Na-dependent Ca2+ efflux from mitochondria by estradiol occurs according to an affinity change of the translocator for Na+, at the same estradiol concentrations that show specific binding to mitochondrial membranes. These data imply that physiological concentrations of estradiol, acting on mitochondrial membrane properties, extragenomically modulate the mitochondrial, and consequently the synaptosomal content of Ca2+, and in that way exert a significant change in nerve cell homeostasis.     

Zinc antagonizes the effect of botulinum type A toxin at the mouse neuromuscular junction

Zn2+ (10-100 microM) elevated the frequency of miniature end-plate potentials (MEPPs) in the mouse diaphragm. The effect did not depend on external Ca2+. Botulinum type A toxin (BTXA, 50 ng/ml) abolished MEPPs almost completely within 30 min. Zn2+ (100 microM) restored MEPPs and increased their frequency after they had been abolished by BTXA in Ca2+ -free solutions. The antagonistic effect of Zn2+ in the Ca2+ -free solution was reduced by exposing the diaphragm to the toxin in the Ca2+ -free solutions containing high K+. Thus, the action of BTXA is probably enhanced by depolarization of the motor nerve terminals.     

Evidence for a role of IFN gamma in control of Listeria monocytogenes in T cell deficient mice.

The role of interferon (IFN) gamma in controlling chronic infections of Listeria monocytogenes (Listeria) was studied in athymic C57BL/6 nu/nu mice, and by treating thymectomized C57BL/6 +/+ mice with monoclonal rat CD4 and CD8-specific monoclonal antibodies (Mab). Mice treated with a combination of the two T cell subset antibodies were similar to athymic, nude mice in being able to control Listeria infection, keeping the titers below 3-5 log10 bacteria per organ, but they could not eliminate them completely. Treatment with antibodies to IFN gamma of nude or CD4+ + CD8+ - T cell-depleted mice suffering from chronic Listeria infection caused a marked increase of Listeria titers in liver and spleen. This result implies a role of IFN gamma in maintaining anti-Listeria resistance in mice lacking mature T cells.