AAEM minimonograph 32: the electrodiagnostic examination in patients with radiculopathies. American Association of Electrodiagnostic Medicine

The anatomy and pathophysiology of radiculopathies are reviewed, and the electrodiagnostic approaches used in evaluating patients with suspected root lesions are discussed. Such electrophysiologic procedures include motor and sensory nerve conduction studies, late-response studies, somatosensory and motor evoked potentials, nerve root stimulation, and needle electromyography. The value and limitations of these different procedures are considered. At the present time, needle electromyography is the single most useful approach. The findings in patients with radiculopathies at different levels are summarized.     

NPs vs. MDs

The cardioprotective effect of cytochrome c preparations was evaluated according to the test for restriction of the size of the myocardial infarct and the effect on the course of acute myocardial ischemia in acute experiments on dogs. Cytochrome c of biotechnological and animal origin and hemtetradecapeptide caused a marked decrease in the size of the myocardial necrosis in experiments on rats: from 68 +/- 4.3% in the control to 32 +/- 3.4, 46 +/- 8.3 and 44 +/- 4.7%, respectively. In dog experiments the cytochrome c agents reduced the intensity of dp/dt decline and decreased the collateral coronary blood flow in acute myocardial ischemic. They produced a beneficial effect on heart bioenergetics, namely, reduced the lactate level in blood flowing from the zone of the ischemia and glucose consumption by the ischemic myocardium. The cardioprotective effect of biotechnological cytochrome c hemtetradecapeptide was practically identical to the effect of the enzyme of animal origin.     

What causes prostate cancer? A brief summary of the epidemiology

Epoetin alfa is the cornerstone of anemia therapy in patients with end-stage renal disease. In addition to stimulating erythropoiesis, Epoetin alfa has been demonstrated to affect hemostasis. Such effects may be important because patients with chronic renal failure have a bleeding diathesis that is multifactorial in origin. Therefore, a computer literature search on the relationship between Epoetin alfa therapy for anemia in patients with end-stage renal disease and platelets, coagulation, coagulation inhibitors, and fibrinolysis was performed. All articles and abstracts reporting original data in the English language on Epoetin alfa and its effect on hemostasis were reviewed. The literature suggests that the effects of Epoetin alfa on the coagulation cascade are of minimal clinical importance. However, Epoetin alfa transiently increases the number of circulating platelets and improves platelet function, and these effects are associated with a return of the bleeding time towards normal.     

An ABC transporter plays a developmental aggregation role in Myxococcus xanthus

Myxococcus xanthus is a gram-negative bacterium which has a complex life cycle. Autochemotaxis, a process whereby cells release a self-generated signaling molecule, may be the principal mechanism facilitating directed motility in both the vegetative swarming and developmental aggregation stages of this life cycle. The process requires the Frz signal transduction system, including FrzZ, a protein which is composed of two domains, both showing homology to the enteric chemotaxis response regulator CheY. The first domain of FrzZ (FrzZ1), when expressed as bait in the yeast two-hybrid system and screened against a library, was shown to potentially interact with the C-terminal portion of a protein encoding an ATP-binding cassette (AbcA). The activation domain-AbcA fusion protein did not interact with the second domain of FrzZ (FrzZ2) or with two other M. xanthus response regulator-containing proteins presented as bait, suggesting that the FrzZ1-AbcA interaction may be specific. Cloning and sequencing of the upstream region of the abcA gene showed the ATP-binding cassette to be linked to a large hydrophobic, potentially membrane-spanning domain. This domain organization is characteristic of a subgroup of ABC transporters which perform export functions. Cloning and sequencing downstream of abcA indicated that the ABC transporter is at the start of an operon containing three open reading frames. An insertion mutation in the abcA gene resulted in cells displaying the frizzy aggregation phenotype, providing additional evidence that FrzZ and AbcA may be part of the same signal transduction pathway. Cells with mutations in genes downstream of abcA showed no developmental defects. Analysis of the proposed exporter role of AbcA in cell mixing experiments showed that the ABC transporter mutant could be rescued by extracellular complementation. We speculate that the AbcA protein may be involved in the export of a molecule required for the autochemotactic process.     

Hepatic energy and substrate metabolism: a possible metabolic basis for early nutritional support in cirrhotic patients

Excimer laser photorefractive keratectomy and excimer laser in situ keratomileusis are relatively new treatment modalities that can be used to correct refractive errors of the eye. They are most commonly used to correct myopia (nearsightedness) but can also be used to correct hyperopia (farsightedness) and astigmatism. The excimer laser alters the refractive state of the eye by removing tissue from the anterior cornea through a process known as photoablative decomposition. This process uses ultraviolet energy from the excimer laser to disrupt chemical bonds in the cornea without causing any thermal damage to surrounding tissue. The modified anterior corneal surface enables light to be focused on the retina, thereby reducing or eliminating the dependence on glasses and contact lenses. We discuss in detail all aspects of excimer laser refractive surgery--techniques, indications and contraindications, clinical outcomes, and complications.     

Positron emission tomography in the detection and management of metastatic melanoma

OBJECTIVE: In women who use oral contraceptives with low estrogen doses, a quiescent endometrium is frequently produced. Further reduction of the estrogen dose would not be expected to alter this effect. In this open-label study, the effects on the endometrium of a monophasic oral contraceptive containing 75 micrograms gestodene and 20 micrograms ethinylestradiol were assessed. METHOD: Biopsies were performed on 25 women on therapy. The biopsies were performed during the late luteal phase (last 7 days) in the pretreatment cycle and during days 15-21 in cycle 6 for 13 subjects (Group A) and during days 15-21 in cycle 3 and during the late luteal phase (last 7 days) in the post-treatment cycle for 12 subjects (Group B). RESULTS: All subjects completed six cycles of treatment. Nine of 13 subjects pretreatment and nine of 12 subjects at cycle 3 were characterized by the pathologist as having a secretory endometrium. Four of 13 subjects at cycle 6 and ten of 11 subjects post-treatment also demonstrated a secretory endometrium. Pre-decidual changes were seen in one, two, two and zero subjects at pretreatment, after three cycles, six cycles, and post-treatment, respectively. Six subjects had an atrophic endometrium at cycle 6. CONCLUSIONS: With monophasic gestodene/ethinylestradiol 75 micrograms/20 micrograms, a secretory or inactive endometrium was present in most subjects. Thus, the effects on the endometrium of this oral contraceptive containing a reduced estrogen dose are consistent with those produced by other low-estrogen-dose combination oral contraceptives.     

A novel isoform of the mitochondrial outer membrane protein VDAC3 via alternative splicing of a 3-base exon. Functional characteristics and subcellular localization

Voltage-dependent anion channels (VDACs) are pore-forming proteins found in the outer mitochondrial membrane of all eucaryotes. VDACs are the major pathway for metabolites through the outer mitochondrial membrane and, in mammals, bind several cytosolic carbohydrate kinases. Whereas yeast contain a single VDAC (YVDAC), to date three isoforms have been described in the mouse that constitute a gene family. We have observed an additional isoform of VDAC3 that appears to be generated via the tissue-specific alternative splicing of a 3-base exon (ATG). The exon is predicted to introduce a methionine 39 amino acids downstream of the amino terminus of the polypeptide. Between exons 3 and 4 is an intronic sequence that potentially encodes the exon, with flanking splice enhancer elements. Expression of this alternative form in the mouse is limited to brain, heart, and skeletal muscle. Complementation of YVDAC-deficient yeast by the two isoforms and with other sequence variants of VDAC3 suggests this residue is an important modulator of VDAC3 function. In transfected mammalian cells both isoforms localize to mitochondria. A similar variant is present in humans.     

Individual differences in arousal and accessibility to information in memory

The authors conducted 9 experiments to test the hypothesis (S. Schwartz, 1975) that arousal influences the accessibility of information stored in memory. They investigated the relationship between arousal levels (as indexed by personality types) and the type of stimuli or cues presented during study or test. They predicted that low-arousal individuals (stable extraverted individuals in Experiments 1-3 and 5-9 and high-impulsive individuals in Experiment 4) would be influenced by semantic stimuli, whereas high-arousal individuals (neurotic introverted individuals in Experiments 1-3 and 5-9 and low-impulsive individuals in Experiment 4) would be influenced by physical (i.e., graphic, phonetic, or both) stimuli. They tested the arousal-accessibility hypothesis by using a variety of tasks including verbal discrimination, false recognition, cued recall, and paired associates. With the exception of the finding that stable extraverted participants performed better than neurotic introverted participants on an incidental associative-matching task (Experiment 3), the results from the verbal discrimination studies (1-5) did not support the hypothesis. In Experiment 6, the authors tested the hypothesis by using a false-recognition task. False alarms varied as a function of phonetic and semantic stimuli, but personality types were not differentially sensitive to the manipulation. The same was true for the cued-recall studies (Experiments 7 and 8); personality types were not differentially sensitive to the semantic and phonetic stimuli. Experiment 9 (paired-associate learning) was a replication of Schwartz's study. The authors found some support for the Schwartz hypothesis: Extraverted participants were adversely affected by semantic similarity. Overall, the findings did not provide much support for the arousal-accessibility hypothesis.     

Dual implication of 2',3'-cyclic nucleotide 3' phosphodiesterase as major autoantigen and C3 complement-binding protein in the pathogenesis of multiple sclerosis

Multiple sclerosis (MS) is characterized by intra-blood-brain barrier immunoglobulin synthesis that persists lifelong. Subcellular fractionation and two-dimensional electrophoresis were used in conjunction with immune precipitation and immunoblotting to identify antigenic determinants for this immunoglobulin. We report that 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNP), a protein associated with oligodendrocyte/myelin membranes, also present in lymphocytes and retina, is one major target for the humoral response. Antibodies to CNP are detected in sera of 74% of MS patients. The antibodies are IgM and are present in serum in high titer as well as in cerebrospinal fluid. The antibody response is temporally persistent, consistent with systemic immune activation and persistent antigenic stimulation. Moreover, CNP is isolated as an immune complex from MS brain. CNP is expressed as two isoforms, with CNPII identical to CNPI but with a 20-amino acid extension at the amino terminus of CNPII; however, the antibody response is exclusively restricted to CNPI. In contrast, both isoforms bind the C3 complement, providing a plausible mechanism in MS central nervous system (CNS) for opsonization of myelin membrane CNP, mediated via the C3 receptor, and phagocytosis of CNP-Ig immune complexes, mediated by membrane Ig Fc receptors of macrophages and CNS microglia.     

Pharmacological modulation of endothelial function by insulin in the rat aorta

The aim of this study was to investigate the transdermal iontophoresis of a newly designed capsaicin derivative, sodium nonivamide propionate (SNP). The iontophoretic permeation of SNP from various pH buffers increased following the decrease of pH values. This trend was consistent with that of sodium nonivamide acetate (SNA) which is another synthetic analogue of capsaicin. However, the iontophoretic permeability of SNP was much lower than that of SNA. SNP was also delivered iontophoretically from hydrogel formulations. It is suggested that ionizable polymers should be avoided for iontophoretic delivery to maintain good penetration capacity of drugs. Both nonionic cellulose polymers of methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC) showed higher iontophoretic flux for SNP than the others did. Furthermore, the flux of SNP leveled off with an increase in the amount of polymers in hydrogel, indicating that the viscosity of vehicles plays an important role in the permeation of SNP. Comparing the various iontophoretic application modes, the discontinuous on/off cyclic mode showed higher penetration capacity than did the continuous mode although they possessed the same electrical energy. Moreover, the desorption time of SNP from skin was approximately 20 min which was longer than that of SNA.