An improved method for the assay of platelet pyruvate dehydrogenase

An improved method for the assay of human platelet pyruvate dehydrogenase is described. By generating the substrate [1-¹⁴C]pyruvate in situ from [1-¹⁴C]lactate plus l-lactate dehydrogenase, the rate of spontaneous decarboxylation is dramatically reduced, allowing far greater sensitivity in the assay of low activities of pyruvate dehydrogenase. In addition, no special precautions are required for the storage and use of [1-¹⁴C]lactate, in contrast to those for [1-¹⁴C] pyruvate. These factors allow a 5–10-fold increase in sensitivity compared with current methods. The pyruvate dehydrogenase activity of normal subjects as determined by the [1-¹⁴C]lactate system was 215 ± 55 pmol · min^?1 · mg^?1 protein (n = 18). The advantages of this assay system are discussed.     

A rapid manual method for routine assay of ascorbic acid in serum and plasma.

A method is described for the assay of ascorbic acid in either serum or heparinized plasma. 1. The assay is based on the reduction of ferric chloride by ascorbic acid with the resulting ferrous ion quantitated by the addition of 2,4,6-tripyridyl-s-triazine to form a purple colour with a maximum absorbance at 595 nm. 2. Uric acid interference has been eliminated by the use of a high molarity acetate buffer and by optimising the amount of TPTZ and ferric chloride used. 3. Protein was found to cause rapid fading of the final colour; it was therefore necessary to remove the protein, by addition of 10% trichloroacetic acid, from the specimen prior to the final assay. This had the added advantage of assisting to stabilize the ascorbic acid prior to final assay. 4. All reagents used are easily obtained and no special equipment is required.     

Illness behaviour profiles in chronic pain: The auckland experience

Two hundred patients with chronic pain, presenting to the Auckland Hospital Pain Clinic, completed the illness behaviour questionnaire (IBQ) developed by Pilowsky and Spence in Adelaide. These authors have identified 6 taxonomic clusters from a numerical analysis of illness behaviour profiles and have described the characteristics of these groups of patients. This study reports the results of a similar analysis of IBQ scores taken from a larger group of patients and clustered using a variant of the K-means algorithm. Ten clusters were derived. These are described and compared with the groups described by Pilowsky and Spence. Both samples have closely similar illness behaviour profiles. Comparisons of the clusters reveal more similarities than differences and we conclude that this independent replication of the Pilowsky and Spence study enhances the validity of the IBQ and the clusters described.     

城市创伤的急诊救治--附719例分析

目的 :对我院急救部 1992— 1999年收治的中度以上创伤患者进行流行病学调查 ,以期对城市创伤的急救提出依据。方法 :从 42批 1145例创伤患者中筛选出中度以上者 719例进行统计分析。结果 :伤员构成 :男5 45例 ,女 174例 ,男∶女为 3.13∶ 1;年龄平均 (32 .3± 16 .7)岁 (4～ 86岁 ) ;创伤评分 (TS)平均 (13.2± 3.7)分 ,格拉斯哥昏迷评分 (GCS)平均 (11.7± 4.3)分 ,Clem mer氏评分 (CRAMS)平均 (7.46± 2 .40 )分 ,创伤严重程度评分 (ISS)平均 (19.3± 11.9)分。复合伤 13例 (1.8% ) ,多发伤 2 49例 (34 .6 % ) ;休克 12 5例 (2 9.9% ) ;脱险率 84.2 % ,抢救成功率 76 .7%。 2 0～ 2 9岁和 30～ 39岁两个年龄段占病例总数 5 7.3%。烧烫伤及火器伤占创伤的 15 .9%和 16 .8% ;机械伤占创伤的 6 7.3% ,创伤发生部位前 4位为四肢、头、胸、腹 ;致死部位前 3位为头、胸、腹 ;死亡发生率前 4位为大血管、骨盆、头、胸。收入重度患者最多的科室为 SICU(5 0 .2 % )。急诊时死亡 6 2例 (多发伤 2 2例、脑外伤 19例、烧伤 11例、刀伤 9例、失血 1例 ) ,手术 2 6例 (成活 6例 )。结论 :交通伤、坠落伤、刀伤及意外事故是城市创伤的主要因素。观念上要重视“白金 10分钟”;开展超级生命支持 ,急诊独立的手术体系并     

Determination of naproxen and its desmethyl metabolite in human plasma or serum by high performance liquid chromatography.

1. A liquid chromatographic method has been developed for the simultaneous determination of the anti-inflammatory agent naproxen and its metabolite, 6-0-desmethyl-naproxen, in human plasma or serum. 2. After addition of p-chlorowarfarin as the internal stardard, plasma is acidified and extracted with either chloroform (for assay of naproxen only) or ethyl acetate (for assay of naproxen and desmethyl-naproxen), the organic solvent is evaporated, the residue is dissolved in acetonitrile and injected onto a reverse phase column coupled with an ultra-violet absorbance detector. 3. Drug and metabolite can be detected readily in concentrations above 2 micrograms per ml in 0.5 ml samples. Salicylic acid and its metabolites and a number of other durgs were found not to interfere with the assay.     

Self-reported vs. actual use of medications in chronic pain patients

Inappropriate or excessive medication use is a commonly observed problem among patients with chronic pain. Comparing patients' self-reported drug use with actual observed drug use, this study examines the incidence, nature and magnitude of drug utilization in a selected population of pain patients and evaluates the reliability of patient estimates of their own drug use. The data support the clinical observation that patients with chronic pain tend to underestimate their medication use. This tendency is greater for narcotic analgesics than for a variety of other medications taken for pain and is greater for women than men.     

Studies on the change of electrophoretic mobility and the decay of catalytic activity of brain-type creatine kinase isoenzyme (CK-BB) following incubation at 37 °C

Incubation of CK-BB in serum (1:3, v/v) at 37°C for 3 h caused a change of its electrophoretic mobility and decay of its catalytic activity. Similar effects were observed following incubation in water. Incubation in saline somehow preserved the electrophoretic mobility but not the catalytic activity. No effect was noted when incubated at 4°C for 3 h. Further study on the rate of decay revealed that the decay in albumin solution (1:50, v/v) is quite similar to that in serum. More dramatic decay was noted when incubated in water and less when incubated in saline. It was further shown that the higher the incubation temperature (4°C, 25°C or 37°C) the faster the decay. The rate of decay of CK-MM was much slower in all conditions of incubation. Determination of isoenzyme activities by means of an immunoprecipitation method again demonstrated that CK-BB lost a great deal of its catalytic activity following incubation at 37°C for 1 h, and hence falsification of the isoenzyme pattern.     

Reversal of morphine and stimulus-produced analgesia by subtotal spinal cord lesions

This study examined the hypothesis that descending inhibitory pathways from brain stem to spinal cord mediate the analgesic effect of both electrical brain stimulation and morphine. In the first set of experiments, the effect of subtotal midthoracic spinal cord lesions on the analgesic effect of electrical stimulation in the periaqueductal gray matter of the rat was examined. In the second, the effect of similar cord lesions on the analgesic effect of intraperitoneal morphine was studied. In both cases, a lesion of the dorsal part of the lateral funiculus (DLF) reduced or abolished the analgesia of the hindlimbs. Analgesia of the forelimbs was unaffected. Lesions of the dorsal columns, which include the corticospinal tract, or lesions of the ventral part of the lateral funiculus had no effect on analgesia. It is concluded that an inhibitory pathway, which descends in the dorsal part of the lateral funiculus and which probably originates in the nucleus raphe magnus of the medulla, mediates the descending control found in both morphine and stimulus-produced analgesia.     

Improved determination of serum calcium with 2-cresolphthalein complexone

This paper describes experimental conditions for reproducible measurement of sodium-lithium countertransport in red blood cells. The assay is sensitive to temperature (10% per °C at 37°C) and the condition of the red cells; it is affected little by changes in intracellular lithium over the range 2–7 mmol/1 or by red cell concentrations with laboratory hematocrits of 0.03 to 0.07. Repeated measurements of the same subjects give day-to-day coefficients of variation of 10% or less. The mean difference for interlaboratory comparisons is 11%.     

Dental sensory receptor structure in human teeth

Electron microscopy was used to study normal human extracted teeth in order to define the junctions between sensory nerve endings and other cells in external pulp and inner dentin at the crown tip. Two sets of associated cells were found: (1) Connective tissue cells. The pulpal fibroblast network made occasional desmosome junctions with the odontoblast network, and the cells of each network formed many gap junctions and desmosomes with one another. (2) Nerve endings. The terminal axons formed a succession of appositions with each other or with Schwann cells in the plexus of Raschkow and the cell-free zone, possibly with fibroblasts inthe cell-free zone and odontoblast layer, and with odontoblasts in the odontoblast layer, predentin and dentin. The appositions between nerve endings and their companion cells at all levels usually maintained a regular intercellular spacing of at least 15–20 nm. In predentin and dentin, axons could be easily identified by their distinctive vesicles and mitochondria, and they often occurred within clusters of adjacent dentinal tubules; in the odontoblast layer axon identification was much more difficult. Axo-axonic appositions were found in the plexus of Raschkow, the cell-free zone, predentin and dentin; in many cases, bare axons were separated from each other only by a 5–10 nm extracellular space. Dental sensory mechanisms are discussed in relation to these observations.     

Hypoalgesia induced by the local injection of phentolamine in the nucleus raphe magnus: blockade by depletion of spinal cord monoamines

Blockade of the noradrenergic input to the nucleus raphe magnus (NRM) by the injection of alpha-adrenergic antagonists produces hypoalgesia. Previous studies show that this hypoalgesia is blocked by the intrathecal injection of either phentolamine or methysergide. The present study demonstrates that depletion of spinal cord serotonin, norepinephrine, or both also blocks this hypoalgesia. Together these studies suggest that the hypoalgesia produced by microinjection of noradrenergic antagonists in the NRM is mediated by the activation of both raphe-spinal serotonergic neurons and bulbospinal noradrenergic neurons.     

Automated radioimmunoassay of nicotine.

We have developed an automated nonequilibrium procedure for the radioimmunoassay of nicotine. The use of a unique iodinated nicotine derivative in this procedure gave a sensitivity of 10 micrograms/l for nicotine with a between-run precision of 7.4% and within-run precision of 6.0%. Nicotine levels of 60 to 67 micrograms/ml were found in subjects 15 min after smoking one standard cigarette. The technique herein reported is a very rapid, and sensitive radioimmunoassay for nicotine and facilitates the determination of nicotine in smoking subjects during the actual process of smoking.     

Polyamine distribution in cellular compartments of blood and in aging erythrocytes.

Human blood was separated into pure preparations of erythrocytes, mononuclear leukocytes, polymorphonuclear leukocytes, platelets, and platelet free plasma. The mean concentrations of putrescine, spermidine, and spermine per 10(9) cells were found to be several orders of magnitude higher for leukocytes than erythrocytes. There was no significant difference between leukocyte types. Platelets and plasma had relatively low levels in proportion to the amounts contributed by erythrocytes and leukocytes to whole blood. Human erythrocytes were age-separated by density and the changes in polyamine concentrations in maturing erythrocytes were documented. There were highly significant statistical differences between young and old red blood cells for putrescine, spermidine and spermine. The clinical use of red blood cell polyamines as an indicator of the activity of the bone marrow in anemic states is suggested.