Membrane properties of rat locus coeruleus neurones

Intracellular recordings were made from neurones in the locus coeruleus contained within a slice cut from rat pons and maintained in vitro. Most neurones fired action potentials spontaneously at frequencies of between 1 and 5 Hz; this did not arise from spontaneous synaptic input but appeared to result from endogenous properties of the membrane conductances. Under voltage clamp at potentials near threshold for action potential generation (? 55 mV) there was a persistent inward calcium current. This current became less with membrane hyperpolarization and was abolished at about ?70 mV. Two potassium currents were observed. The first had properties similar to that generally described as the “fast” potassium current (I_K,A); it flowed transiently (for about 200 ms) when the membrane potential passed from about ?65 to ?45 mV, and was blocked by 4-aminopyridine. The second was a calcium-activated potassium current (I_K,Ca); it flowed for several seconds following a burst of calcium action potentials. Spontaneous and evoked action potentials had both tetrodotoxin-sensitive and tetrodotoxin-resistant components. The latter was apparently due to calcium entry. The potential changes occurring during the spontaneous firing of locus coeruleus neurones could be reconstructed qualitatively from the ionic conductances observed. The membrane properties of the locus coeruleus neurones were remarkably uniform; however, about 5% of cells impaled within the region of the locus coeruleus were electrophysiologically distinct. These atypical cells had short duration action potentials, did not fire spontaneously and had large spontaneous depolarizing synaptic potentials.     

Vaccinated mice remain more susceptible to Mycobacterium tuberculosis infection initiated via the respiratory route than via the intravenous route

Mice given Mycobacterium tuberculosis bacilli via the respiratory route succumbed much sooner to infection than mice given 1,000 times more bacilli via the intravenous route. Vaccination provided increased protection to an M. tuberculosis challenge infection; however, mice infected via the respiratory route remained much more susceptible.     

Amplification of rhinovirus specific nucleic acids from clinical samples using the polymerase chain reaction

We describe a novel method for the detection of human rhinoviruses in clinical samples, using the polymerase chain reaction. Two synthetic oligonucleotide primers were produced that bind in the 5' noncoding region of all rhinovirus serotypes tested, about 350 nucleotides apart, and were used to prime polymerase chain reaction amplification of the intervening stretch of DNA. The product of this reaction, which can be clearly visualized by gel electrophoresis, is a discrete 380 bp band, the occurrence of which is diagnostic of the presence of a rhinovirus in the clinical sample analysed. The technique, which is rapid, sensitive, and reliable, has been used successfully for all the different rhinovirus serotypes tested to date in our laboratory. However, the sensitivity of detection is greatly dependent on the inclusion of both tRNA and vanadyl complexes during the viral RNA extraction process. Using this technique, under optimal conditions, we were able to detect virus in clinical samples with titres as low as TCID50 10(2.5).     

Resistance ranking of some common inbred mouse strains to Mycobacterium tuberculosis and relationship to major histocompatibility complex haplotype and Nramp1 genotype.

Six common inbred strains of mice and their F1 hybrids were examined for resistance to infection with the H37Rv strain of Mycobacterium tuberculosis. According to survival times after inoculation of 10(5) CFU intravenously (i.v.), the mice could be classified as being either highly susceptible (CBA, DBA/2, C3H, 129/SvJ) or highly resistant (BALB/c and C57BL/6). F1 hybrids of susceptible and resistant strains were resistant. Although an examination of a limited number of H-2 congenic strains showed that the H-2k haplotype could confer susceptibility on a resistant strain, it was evident that non-major histocompatibility complex (MHC) genes were much more important. Resistant strains all possessed the susceptibility allele of the anti-microbial resistance gene, Nramp1. Results obtained with selected strains infected with 10(2) CFU of M. tuberculosis by aerosol agreed with the results obtained with mice infected i.v. The size of the bacterial inoculum was important in distinguishing between resistant and susceptible strains, in that a 10(7) inoculum overcame the resistance advantage of one strain over another.     

煤矿工人上消化道疾病的现况研究

目的：探讨煤矿工人上消化道疾病的患病现况,方法：按照整群随机抽样的方法在山东兖州,河北开滦,辽宁铁法选取３０６人,以胃镜进行普查。结果：矿区工人总的上消化道疾病患病率为７７．８％,以红斑性胃炎为主,占各种上消化道疾病的４１．５％井下采煤和掘进作业工人的患病率高于井下其他作业工人,后者的患病率与井上工人的患病率一致,各矿区之间,以山东兖州的工人患病率最高,湖北开滦最低。结论 煤矿工人上消化道疾病患病     

纤维状矿物粉尘对肺泡巨噬细胞膜损伤的机制研究

评价来自全国６个不同矿床的６种纤维矿物粉尘的细胞膜毒性,探讨其受损机制,采用体外细胞培养技术及扫描电镜方法观察纤维状矿物粉尘对肺泡巨噬细胞膜的通透性、膜流动性、膜形成的影响。结果纤维硅灰石,斜发沸石无细胞膜毒性,纤状海泡石、纤状坡缕石、纤状水镁石、纤状蛇纹石石棉表现出不同程度的细胞膜毒性。纤维状矿物粉尘对细胞膜毒性与其表面特性有关     

小儿急性中毒77例临床分析及预防

本文对近 10年收治 77例急性中毒的患儿进行了回顾性分析。观察到 :年幼小儿、农村小儿发病率较高 ,因误服药物、鼠药的食物致急性中毒的患儿较多 ,死亡病例均因就诊太晚。提示 :对急性中毒必须早诊断、早治疗。并提出减少小儿意外中毒的关键应从预防着手     

Dorsal root ganglionectomy for failed back surgery syndrome: a 5-year follow-up study.

Dorsal root ganglionectomy has been suggested as a method for the treatment of chronic intractable radicular pain, with theoretical advantages over dorsal rhizotomy, which does not interrupt ventral root afferents. The indications for these procedures in patients with persistent pain following lumbosacral spine surgery are not well established. Long-term results have been reported infrequently, and no published series has a mean follow-up period of more than 30 months. The authors have reviewed their experience with a series of 13 patients with failed back surgery syndrome, in whom dorsal root ganglionectomy was performed. Patients were selected on the basis of clinical presentation and diagnostic root blocks suggesting a monoradicular pain syndrome. Follow-up data were obtained at a mean of 5.5 years following dorsal root ganglionectomy. Follow-up interviews to assess outcome were conducted by a disinterested third party. Treatment "success" (at least 50% sustained relief of pain and patient satisfaction with the result) was recorded in two patients at 2 years after surgery and in none at 5.5 years. Equivocal success (at least 50% relief, without clearcut patient satisfaction) was recorded in one patient at 2 and at 5.5 years postoperatively. Improvements in activities of daily living were recorded in a minority of patients. Loss of sensory and motor function was reported frequently by patients. A minority of patients had reduced or eliminated analgesic intake. These results suggest that dorsal root ganglionectomy has a limited role in the management of failed back surgery syndrome, and that methods to select patients to receive this procedure should be refined or alternative approaches should be considered.     

钴辐照对板蓝根抗内毒素作用的影响

目的：研究Co辐射灭菌法对板蓝根抗内毒素作用的影响。方法：本文用3个剂量的Co射线辐照板蓝根药材，并用鲎试剂法与家兔法测定辐照前后板蓝根内毒素作用的变化，结果表明Co辐照对板蓝根抗内毒素作用的影响与辐照剂量有关，10Kgy及以下剂量的辐照不会造成明显影响.