Determination of biogenic amines in fish implicated in food poisoning by micellar electrokinetic capillary chromatography

A micellar electrokinetic capillary chromatography (MECC) method for the simultaneous determination of seven biogenic amines in fish was developed. The peaks of all components were successfully separated within 11.5 min. MECC was performed with 0.06 M sodium deoxycholate in 0.02 M borate buffer (pH 9.2)-methanol (95:5, v/v) solvent. The average recoveries for all components ranged from 84.4 to 100.3%. The application of this method to detect amines in fried marlin fillet implicated in a food poisoning incident indicated that a high level (56.24 mg/100 g) of histamine was present in the sample. Another 10 fish samples collected from markets were also analyzed and did not contain detectable levels of histamine (<2.5 mg/100 g).     

Induction of spheroid cytoplasmic bodies in a rat muscle by local tetanus

The term "cytoplasmic body" or "spheroid body" myopathy refers to a heterogeneous group of familial or sporadic diseases characterized primarily by the presence of abundant spheroid or cytoplasmic bodies in the muscles. The morphogenesis of these inclusions remains unclear. This article describes the induction and evolution of spheroid cytoplasmic bodies (SCBs) in the rat plantaris muscle (PL) with local tetanus, which was induced in rats by the injection of a minute amount of tetanus toxin. In contrast to the tetanized soleus muscle (SOL), which developed core fibers (central cores, minicore, target fiber, targetoid fiber, and rods), the tetanized PL produced numerous SCBs with a predictable time course. They were induced in both type 1 and 2 fibers of PL, which is composed predominantly (95%) of type 2 fibers, in contrast to SOL (85% type 1 fibers). Factors inducing SCBs may include immobilization, shortening, intact innervation, and disuse atrophy.     

Effects of low-level microwave irradiation on amphetamine hyperthermia are blockable by naloxone and classically conditionable

In a series of experiments, we investigated the effects of pulsed low-level microwave irradiation on amphetamine-induced hyperthermia in the rat. Rats were irradiated in a 2,450-MHz cylindrical waveguide exposure system at 1 mW/cm², 2 s pulses, 500 pps, average SAR of 0.6 W/kg. Acute (45 min) exposure to microwaves attenuated amphetamine-induced hyperthermia. This effect was blocked by pretreatment of the animals with the narcotic antagonist naloxone. In another experiment, rats were subjected to ten daily sessions of microwave exposure (45 min/session). On day 11, amphetamine-induced hyperthermia was studied in the animals immediately after a session of either microwave or sham exposure. Similar to the acute effect, amphetamine-induced hyperthermia was attenuated in rats irradiated with microwaves (unconditioned effect). In the sham-irradiated animals we observed a potentiation of the amphetamine-induced hyperthermia, which was a conditioned effect of microwaves. Thus, the conditioned effect (potentiation) was opposite in direction to the unconditioned effect (attenuation). No tolerance developed to the unconditioned effect after subchronic exposure. Furthermore, both conditioned and unconditioned effects of microwaves on amphetamine-induced hyperthermia could be blocked by treatment with naloxone. These data suggest that (1) microwave irradiation may activate endogenous opioids, which in turn alter the actions of psychoactive drugs, and (2) the effect of microwaves on drug action can be classically conditioned. Offprint requests to: H. Lai     

Hypertrophic mononeuritis clinically presenting with painful legs and moving toes

A 40-year-old woman presented with progressive lower leg pain and spontaneous toe movement. The EMG showed a posterior tibial nerve mononeuropathy and continuous myokymic discharges in posterior tibial-innervated muscles. The MRI revealed a markedly enlarged posterior tibial nerve. Toe movements and myokymia were unaffected by the proximal transection of the lesion but ceased abruptly when the distal end of the fusiform "tumor" was resected, suggesting that spontaneous electrical foci may have been located along the nerve lesion. The markedly enlarged nerve segment contained edematous, swollen fascicles with marked Schwann cell onion-bulb lesions and angiocentric, lymphocytic, and lymphofollicular infiltration. This nerve lesion is an example of a newly recognized entity called hypertrophic mononeuritis.     

Cerebral uptake and metabolism of (11C) Vinpocetine in monkeys: PET studies]

Vinpocetine, a vinca alkaloid, is a therapeutic agent widely used in the treatment of acute and chronic stroke patients. To explore the uptake and distribution of vinpocetine in the primate brain, vinpocetine was labelled with 11C and positron emission tomography (PET) was used to measure the uptake and distribution of 11C-vinpocetine in the brain and the trunk of a cynomolgous monkey. HPLC was used to determine the concentration of vinpocetine and its labelled metabolites in blood and plasma. Following the radioligand's intravenous administration, after an initial peak, the total concentration of radioactivity in blood was relatively stable with time. The uptake of 11C-vinpocetine into the brain was rapid and about 5% of the total injected radioactivity was present in the brain two minutes after drug administration. These facts indicate that the compound passes the blood-brain barrier readily and enters the brain. The radioactivity uptake was heterogeneously distributed among brain regions. The highest concentrations were found in the thalamus, the basal ganglia and certain neocortical regions. In an earlier PET investigation on chronic stroke patients the highest increases in cerebral blood flow and glucose metabolism after intravenous vinpocetine treatment occurred in these anatomical structures. The heterogenous regional distribution of vinpocetine and the observation that the highest uptake values in brain structures go parallel with the greatest regional blood flow and glucose metabolic rate increases indicate that direct CNS effects of vinpocetine should be considered as an explanation for the therapeutic effects. The confirmation of this suggestion requires further investigations.     

Reliability of the American Medical Association guides' model for measuring spinal range of motion. Its implication for whole-person impairment rating

STUDY DESIGN: Repeated measures design for intra- and interrater reliability. OBJECTIVES: To determine the intra- and interrater reliability of the lumbar spine range of motion measured with a dual inclinometer, and the thoracolumbar spine range of motion measured with a long-arm goniometer, as recommended in the American Medical Association Guides. SUMMARY OF BACKGROUND DATA: The American Medical Association Guides (2nd and 4th editions) recommend using measurements of thoracolumbar and lumbar range of movement, respectively, to estimate the percentage of permanent impairment in patients with chronic low back pain. However, the reliability of this method of estimating impairment has not been determined. METHODS: In all, 34 subjects participated in the study, 21 women with a mean age of 40.1 years (SD, +/- 11.1) and 13 men with a mean age of 47.7 years (SD, +/- 12.1). Measures of thoracolumbar flexion, extension, lateral flexion, and rotation were obtained with a long-arm goniometer. Lumbar flexion, extension, and lateral flexion were measured with a dual inclinometer. Measurements were taken by two examiners on one occasion and by one examiner on two occasions approximately 1 week apart. RESULTS: The results showed poor intra- and interrater reliability for all measurements taken with both instruments. Measurement error expressed in degrees showed that measurements taken by different raters exhibited systematic as well as random differences. As a result, subjects measured by two different examiners on the same day, with either instrument, could give impairment ratings ranging between 0% and 18% of the whole person (excluding rotation), in which percentage impairment is calculated using the average range of motion and the average systematic and random error in degrees for the group for each movement (flexion, extension, and lateral flexion). CONCLUSIONS: The poor reliability of the American Medical Association Guides' spinal range of motion model can result in marked variation in the percentage of whole-body impairment. These findings have implications for compensation bodies in Australia and other countries that use the American Medical Association Guides' procedure to estimate impairment in chronic low back pain patients.     

Role of macrophages in onion-bulb formation in localized hypertrophic mononeuritis (LHM).

A unique pathogenetic process for onion-bulb (Ob) formation is disclosed with disclosed with immunohistochemistry and electron microscopy. Biopsy of a swollen segment of tibial nerve from a 42 year-old white female histologically demonstrated diffuse and angiocentric lymphocytic infiltrate in both endo- and perineurium with occasional lymphofollicular formation. Extensive Ob formation of nerve fibers was most striking with or without associated lymphocytes. Axis-cylinders were intact in the majority of Ob. Immunocytochemically, Ob are composed of alternately laminated leaflets of Schwann cells (S100+) and mononuclear macrophage (HAM56+/LeuMl+/Muramidase+) processes but no perineurial (EMA+) cells. Immunohistochemical evidence of antigen presentation (HLA-DR/LN3+/Ia+) was confined to macrophages. Electron microscopy insinuates that intricate interactions between macrophages and Schwann cells exists. Putative inhibition of remyelination along with proliferation of Schwann cells most probably is secondary to the effects of macrophages secretory products. No direct participation of B or T lymphocytes was detected in Ob. Thus, modified macrophages may emit a factor for concomitantly promoting proliferation of Schwann cells and an enzyme for myelin breakdown. In addition, only a few macrophages could be detected in some Ob and could be easily overlooked or misinterpreted as "vacuolated fibroblasts", if no immunohistochemical correlation is made, as modified macrophages making the external leaflets of Ob are more vacuolated.     

Tumorigenicity of 7, 12-dimethylbenz[a]anthracene, its hydroxy-methylated derivatives and selected dihydrodiols in the newborn mouse

The newborn mouse lung adenoma model has been shown to be asensitive test for studying the tumor-igenicity of bay regiondiol epoxides and their precursor dihydrodiols. When a totaldose of 28 nmol of 7, 12-dimethylbenz[a]anthracene (DMBA) orits derivatives was injected i.p. into the preweaning mice,it was found that the 3, 4-dihydrodiols of both DMBA and 7-hy-droxymethyl-12-methylbenz[a]anthracenecaused 13.3 and 4.1 times more lung adenomas than DMBA, respectively.The mice treated with the 5, 6- and 8, 9-dihydro-diols of DMBA,7-hydroxymethyl-12-methylbenz[a]-anthracene and its 5, 6- 8,9-and 10,11-dihydrodiols, 7-methyl-12-hydroxymethylbenz[a]an-thraceneand 7,12-dihydroxymethylbenz[a]anthracene developed a levelof lung adenomas/mouse less than Mold higher than that foundin the DMSO-treated control group. Liver tumors also developedin some of the mice. The percentage of mice with liver tumorsalso indicated that the 3, 4-dihydrodiols of both DMBA and 7-hydroxymethyl-12-methylbenz[a]anthracenewere more tumorigenic than DMBA itself. These data indicatethat the 3, 4-dihydrodiols of both DMBA and its 7-hydroxymethylderivative may be proximate carcinogenic metabolites of DMBAin the newborn mouse.