Relationship between potential and impedance change associated with excitation of the nerve (author's transl)

The action potential or the potential change and the impedance change associated with excitation of the sciatic nerve and electric nerve model (ENM, the equivalent circuit of the nerve fiber), were recorded by means of AC bridge supplied of AC of 13 kHz. Records were taken in excitation at the stimulated site by the square current of different duration, exponentially increasing current of different increasing gradient. Records were also taken in propagated excitation, in excitation elicited in refractory period and at the polarized site of the inactive nerve and ENM. By observation of these records, the following results were obtained.1. With respect to potential changes in nerve, two kinds of changes were found, namely, the one was in cause and effect relationship with the impedance change and the other was without relation to impedance change. 2. In the course of the action potential, both kinds of potential changes were found.     

Detailed analysis of the latencies of median nerve somatosensory evoked potential components, 2: Analysis of subcomponents of the P13/14 and N20 potentials

Detailed analysis of P13/14 and N20 wavelets was performed for 62 normal subjects and patients with various lesions along the somatosensory pathway. A histogram of the latencies of all the identified P13/14 wavelets (measured from P13/14 onset) demonstrated three latency-groups, which were named P13, P14a and P14b subcomponents. The relationship between the three newly identified subcomponents and the conventional naming of P13 and P14 was inconstant, indicating the ambiguity of the latter. P14b was most prominent in the contralateral central region, and therefore a P15 positivity slightly after P14b was often recorded in the CPc-Fz and CPc-CPi leads (CPc and CPi are centroparietal electrodes contralateral and ipsilateral to the stimulation). P14b/P15 was lost even in patients with cortical lesions, and thalamocortical fibers were assumed for its origin. The CPc-Fz and CPi-Fz leads registered a low negativity named broad N13', suggesting frontal predominance of the overall P13/14 complex. Both P13 and P14a were identified in a patient with a pontine lesion, and a caudal brainstem origin for both was suspected due to the onset of two repetitive bursts of the ascending lemniscal volley. We refuted the presynaptic origin of the scalp P13 potential and pointed out that a prolonged and/or polyphasic P11 frequently observed in patients with high cervical lesions can be mistaken as scalp P13. A histogram of the latencies of all the identified negative wavelets of N20 in the CPc-Fz lead (measured from N20 onset) revealed five definite latency-groups, which were named N20a, N20b, N20c, N20d and N20e subcomponents. The highest peak of N20 actually corresponded to either N20b, N20c or N20d, and this uncertainty, which must be related to intracortical processes, resulted in a large instability of the N20 peak latency as well as the age and sex dependence of the N20 onset-peak interval, both of which were demonstrated by our preceding study (Sonoo, M., Kobayashi, M., Genba-Shimizu, K., Mannen, T. and Shimizu, T. Detailed analysis of the latencies of median nerve SEP components, 1: selection of the best standard parameters and the establishment of the normal values. Electroenceph. clin. Neurophysiol., 1996b, 100: 319-331). Negative subcomponents in the CPc-NC lead and positive subcomponents in the Fz-NC lead constituted mirror images of each other, which suggested that these subcomponents were generated within area 3b.     

Measurement of the membrane potential generated by complex I in submitochondrial particles

To investigate the energy-conserving function of the NADH:ubiquinone reductase (complex I), we have selected oxonol VI [bis(3-propyl-5-oxoisoxazol-4-yl)pentamethine oxonol] as the most sensitive probe for measuring the reactions of membrane potential generation in submitochondrial particles. Calibration of the oxonol signals with potassium diffusion potentials shows a non-linear response after a threshold around -50 mV. Thermodynamic evaluations indicate that the upper limit of the oxonol response to the potential generated by complex I is around -220 mV, which is close to the maximal protonmotive force in coupled submitochondrial particles. NADH addition to particles in which ubiquinol oxidation is blocked by inhibitors of other respiratory complexes generates oxonol signals corresponding to membrane potentials of -130 to -180 mV. These signals are produced by about four turnovers of the complex reducing endogenous ubiquinone (i.e. non-steady-state conditions) and are equivalent to a charge separation similar to that of the antimycin-sensitive reactions of ubiquinol:cytochrome c reductase (complex III). The transient oxonol signals under non-steady-state conditions are thus informative of crucial steps in the electrogenic reactions catalyzed by complex I. The possible nature of these electrogenic reactions is discussed in relation to proposed mechanisms for complex I.     

The association between different patterns of hand symptoms and objective evidence of median nerve compression: a community-based survey

OBJECTIVE: To examine the association between different patterns of hand symptoms and the presence of delayed nerve conduction in the general population. METHODS: We performed a 2-stage screening survey involving a questionnaire on current hand symptoms, and nerve conduction testing in samples of subjects with and without symptoms. Of 648 respondents to the symptom questionnaire, 212 reported hand symptoms. In all, 155 were tested for nerve conduction of sensory and motor median nerve latencies, including 40 who had reported no symptoms. Patterns of hand symptoms were compared with nerve conduction results and associations weighted back to the general population. RESULTS: The presence of any hand symptoms had only a 40% sensitivity for delayed nerve conduction on latency testing. The presence of typical symptoms of carpal tunnel syndrome had a much lower sensitivity. CONCLUSION: In a community setting, the distribution of hand symptoms does not usefully correlate with the presence of delayed nerve conduction in the median nerve.     

Evidence that dorsal-ventral differences in gap junctional communication in the early Xenopus embryo are generated by beta-catenin independent of cell adhesion effects

Within the limits of the previously proposed conception concerning the dynamical domain organization of receptor molecules in biological membranes the possible role of receptor domains (RD) of plasma membranes in the mechanism of carcinogenesis is discussed. On the basis of extensive experimental material accumulating to present by study of different aspects of carcinogenesis, and based on the key role of receptor domains of plasma membranes in this process the attempt has been made to build the general theory of carcinogenesis. Particular attention is given to the analysis of possible genetically depended changes in the system of cell division and cell differentiation control, which may be responsible for the appearance of non-malignant and malignant tumours in the organism, and also to the consideration of the conditions of the appearance of clones of transformed cells with uncontrolled growth in the organism. Differences in the molecular mechanisms of the appearance of non-malignant and malignant tumours are explained.     

The size of lymph nodes in the neck on sonograms as a radiologic criterion for metastasis: how reliable is it?

Modern imaging for neck node metastases has increased our ability to predict the presence of palpably occult metastases and predict the resectability of large metastases. The accuracy of CT scans, MR imaging, but especially US-FNAC, has increased to such an extent that clinical consequences are being attached to negative radiologic findings in a clinically N0 neck. As not all palpably occult metastases can be detected, especially when they are micrometers, follow-up should be strict, with use of US-FNAC in the neck observed instead of treated electively.     

Relation between size of optic disc and thickness of retinal nerve fibre layer in normal subjects

The genus Clinostomum is a cause of parasitic laryngo-pharyngitis. We report the 15th case of Clinostomum sp. infection in Japan. A 29-year-old female visited our hospital because of throat discomfort and expectoration of a worm by sneezing on November 17, 1997. The pharyngitis was caused by the worm. The worm was morphologically identified as the adult of the genus Clinostomum.     

Synovialectomy and reconstruction of the retinaculum flexorum in median nerve decompression: technique and early results

We studied the efficiency of platelet collection by the Mobile Collection System (MCS) using two types of experimental protocols and evaluated the effect of storage at 22 degrees C on the platelet concentrates (PC). MCS is a new blood cell separator that combines discontinuous flow features with a new computerized operating system and can be used to harvest either full units of apheresis PC (SDP protocol) or half units of PC together with one to two units of plasma (PLP protocol). On the average, 1.98 x 10(11) +/- 0.46 x 10(11) (mean +/- SD) platelets were obtained by the PLP protocol and 3.01 x 10(11) +/- 0.70 x 10(11) and 4.2 x 10(11) +/- 1.12 x 10(11) by the early and later versions of the SDP protocols, respectively. The mean number of WBC per PC ranged from 3.3 to 4.7 x 10(8). During the storage period pH stayed above 7.0. On the average, the production of one molecule of lactate corresponded to the consumption of 0.538 molecules of glucose, indicating that less than 8% of glucose was consumed by the oxidative pathway. There were only small increases in LDH and B thromboglobulin concentrations. Furthermore, the ability of platelets to recover from osmotic shock and to aggregate following exposure to dual agonists declined only slightly during storage, indicating that both viability and function of platelets collected by the MCS were preserved during storage.     

Gross anatomy of the accessory nerve and vagus nerve of the head and cranial neck region in the Bactrian camel

The alpha2-adrenergic system is involved in the regulation of food intake in animals but its effects on feeding in humans are unknown. We hypothesized that clonidine administration would stimulate food intake in healthy human subjects. Ten men and 4 women, all physically and psychiatrically healthy, received clonidine 3 microg/kg or placebo, orally, in blinded, balanced, randomized order. Consumption of a liquid test meal was measured; also, serum growth hormone levels were used as a secondary measure of clonidine effects. Visual analog scale ratings of hunger, satiety, and sedation were obtained before, during, and after the test meal. A subset of five subjects also received 1.5 microg/kg clonidine, in addition to the two trials described above. Test meal consumption was greater following placebo than following clonidine. Sedation ratings were substantially higher at all time points after clonidine and correlated with meal consumption (correlation coefficient r = -0.584; p = 0.028). Hunger and satiety ratings did not differ. The 1.5 microg/kg dose did not provide different effects on feeding from that seen with placebo. Contrary to our hypothesis, clonidine did not stimulate food intake in humans. Sedation associated with clonidine administration may have suppressed any effects on feeding.     

The stiffness of the crossbridge is a function of the intrinsic protein osmotic pressure generated by the crossbridge itself

A model is presented that makes it possible to determine the stiffness of the crossbridge from protein osmotic stress experiments. The model was elaborated while studying the osmotic properties of F-actin and of myosin subfragment-1 F-actin. These studies showed that the elastic modulus by bending of the monomer is directly related to the intrinsic protein osmotic pressure of the system. At a protein osmotic pressure of 1.8 x 10(5) dynes/cm2, the physiological protein osmotic pressure of frog skeletal muscle, it was found that the elastic moduli by bending of the monomer in F-actin and in the myosin subfragment-1 decorated F-actin are 6.5 X 10(7) and 3.3 X 10(8) dynes/cm2, respectively. The value of the elastic modulus by bending of the monomer in the myosin subfragment-1 decorated F-actin compares favorably with the values of the elastic modulus by stretching determined in skeletal muscle fibres.     

The P3a wave of the auditory event-related potential reveals registration of pitch change during sufentanil anesthesia for cardiac surgery

BACKGROUND: The N1 and P3 waves of the auditory event-related potential provide information on consciousness and cortical function. The N1 wave is reduced during states of low vigilance. The P3 wave occurs only for stimuli that somehow capture the subject's attention. There are two types of P3:P3a and P3b. The P3a predominates frontally and probably occurs when the subject simply notices the stimulus. The P3b predominates parietally and indicates conscious awareness of the evoking stimulus. The N1 and P3 were recorded in 12 patients during cardiac surgery under sufentanil anesthesia to search for unintentional awareness. The study was limited to the period before cardiopulmonary bypass. METHODS: After premedication with diazepam, morphine, and scopolamine, sufentanil was used for induction (mean dose, 7.9 micrograms/kg) and maintenance (4 micrograms/kg) of anesthesia. No other anesthetics were administered. Recordings were obtained before induction, during induction after loss of consciousness, after tracheal intubation before incision, and before cardiopulmonary bypass. RESULTS: The N1 was attenuated significantly by sufentanil but was not abolished. The P3b occurred only during preinduction. There was no P3 during induction. There was a P3a during postintubation and precardiopulmonary bypass. CONCLUSIONS: The attenuation of N1 from induction onward reflects a decrease in the level of arousal caused by sufentanil. A P3a during postintubation and precardiopulmonary bypass indicates that pitch discrimination at the cortical level occurs but does not prove that conscious awareness has occurred. Whether or not the P3a reflects the regaining of consciousness is not known.     

Intracellular proteolytic cleavage of 9-cis-retinoic acid receptor alpha by cathepsin L-type protease is a potential mechanism for modulating thyroid hormone action

We previously reported that the responsiveness of hepatocytes to thyroid hormone is markedly attenuated when they were cultured as monolayers rather than spheroids. To elucidate the mechanisms underlying the altered responsiveness, thyroid hormone receptor auxiliary proteins in the hepatocytes were analyzed by electrophoretic mobility shift assay. The major thyroid hormone receptor auxiliary protein was identified as 9-cis-retinoic acid receptor alpha (RXRalpha) in the hepatocytes regardless of the culture conditions. The cytoplasmic fraction was shown to contain a protease(s) that cleaves RXRalpha at its amino terminus. The presence of the protease in the cytosol, but not in the nucleus, was ascertained by incubating full-length 35S-labeled RXRalpha with each fraction. Using various protease inhibitors, it was shown that cathepsin L-type protease could participate in the cleavage of the RXRalpha. The enzyme activity was much higher in the monolayers than the spheroids. Inhibition of this enzyme activity in the monolayer hepatocyte resulted in the increase of nuclear RXRalpha protein and the augmentation of T3-dependent induction of spot 14 mRNA. These results suggest that the changes in cathepsin L-type protease activity in the cytosol may alter the turnover of RXRalpha in the nucleus and modify the function of steroid receptor superfamilies that heterodimerize with RXRalpha.     

Association between social environment and aging of the brain: evaluation with the event-related potential P300

PURPOSE AND METHODS: To investigate the association between social environment and aging of the brain, we studied P300 event-related evoked potentials in 95 normal elderly subjects living in different social environments. The subjects were divided into two groups: 22 healthy people living in old-age homes (average age 76.5 +/- 5.6 years, average Hasegawa Dementia Scale-Revised 27.4 +/- 2.5), and 93 healthy people living in their own homes (average age 74.1 +/- 5.4 years, average Hasegawa Dementia Scale-Revised 28.3 +/- 2.3). Target and Novelty P300 were recorded by using an auditory oddball paradigm. There were no differences in risk factors for strokes or in findings on magnetic resonance imaging between the two groups. RESULTS: Cognitive function (Okabe's Score and Koh's Block Design Test) were lower in those living in an old-age home than in those living in their own homes. Both target and novelty N100 examinations showed no significant differences in amplitude or latencies between the two groups. However, P300 latencies were larger among those living in an old-age home than among those living in their own homes; P300 amplitudes in the two groups were similar. Those living in an old-age home also had greater age-associated declines in function, as shown by longer latencies in target P300 than in novelty P300. CONCLUSION: Social-environmental factors are closely associated with the aging of the brain.     

IFN-gamma-induced TNF-alpha is a prerequisite for in vitro production of nitric oxide generated in murine peritoneal macrophages by IFN-gamma

Dopamine is formed form L-tyrosine by tyrosine hydroxylase and aromatic L-amino acid decarboxylase. In addition to this pathway, however, the formation of catecholamines, including dopamine, from trace amines such as tyramine by hepatic microsomes has been demonstrated. In this study, we investigated the formation of dopamine from trace amines, using human hepatic microsomes and human cytochrome P450 (CYP) isoforms expressed in yeast. Among the 11 isoforms of human CYP expressed in yeast, CYP2D6 was the only isoform exhibiting strong ability to convert p-tyramine and m-tyramine to dopamine. In studies with human hepatic microsomes, the hydroxylation of tyramine to dopamine was inhibited by bufuralol, a typical substrate for CYP2D isoforms, and anti-CYP2D1 antiserum. This is the first report showing that CYP2D is capable of converting tyramine to dopamine. The Km values of CYP2D6, expressed in yeast, for p-tyramine and m-tyramine were 190.1 +/- 19.5 microM and 58.2 +/- 13.8 microM, respectively. Tyramine is an endogenous compound which exists in the brain as a trace amine but is also an exogenous compound which is found in foods such as cheese and wine. Our results suggest that dopamine is formed from endogenous and/or exogenous tyramine by this CYP2D isoform.     

Complete excision of the lower trunk and C8 and T1 nerve roots in a patient with Pancoast tumor with a resulting fully functional hand

OBJECTIVE: To establish the frequency of the atypical glandular cells of uncertain significance (AGCUS) category, and its subcategories, as defined by the Bethesda System (TBS). METHODS: Our computerized records of cervical/vaginal cytology specimens submitted from January 1, 1993, through December 31, 1995, were retrospectively reviewed for specimens diagnosed as AGCUS. When appropriate, our subcategory of "AGCUS favor premalignant/malignant lesion" was further qualified as "favor endocervical adenocarcinoma in situ" or "suspicious for endometrial carcinoma." The number of specimens and patients diagnosed for each subcategory were grouped by calendar year. Differences in frequency between time periods were tested for statistical significance using chi 2 analysis. RESULTS: AGCUS was diagnosed in 1181 of 177,715 submitted specimens (0.66%). The frequency of subcategories was as follows: "favor reactive" (65%), "unable to further classify" (30%), "favor premalignant/malignant" (2.9%), "suspicious for endometrial carcinoma" (1.9%), and "favor endocervical adenocarcinoma in situ" (0.4%). From 1993 to 1995 there was an increase in the rate of diagnosis of AGCUS (0.55 to 0.73%; P < 0.001) and a decrease in the percentage of specimens with AGCUS subclassified as "favor premalignant/malignant" (6.2 to 0.5%; P < 0.001). Other subcategories showed no significant change in frequency over this time period. The rate of biopsy-proven preinvasive or invasive lesions in AGCUS patients also showed no significant change from year to year over this time period. CONCLUSION: The AGCUS diagnosis can be anticipated at a low but consistent rate from a cytology laboratory using TBS. Any comparison of laboratories should take into consideration the change in reporting frequencies that occurs as part of the "learning curve" following introduction of TBS reporting. Uniform diagnostic criteria and additional reports with large numbers of cytologic specimens will be needed to establish the expected frequency of AGCUS and its subcategories.     

Lignin monomer composition is determined by the expression of a cytochrome P450-dependent monooxygenase in Arabidopsis

The phenylpropanoid pathway provides precursors for the biosynthesis of soluble secondary metabolites and lignin in plants. Ferulate-5-hydroxylase (F5H) catalyzes an irreversible hydroxylation step in this pathway that diverts ferulic acid away from guaiacyl lignin biosynthesis and toward sinapic acid and syringyl lignin. This fact led us to postulate that F5H was a potential regulatory step in the determination of lignin monomer composition. To test this hypothesis, we have used Arabidopsis to examine the impact of F5H overexpression. Arabidopsis is a useful model system in which to study lignification because in wild-type plants, guaiacyl and syringyl lignins are deposited in a tissue-specific fashion, while the F5H-deficient fah1 mutant accumulates only guaiacyl lignin. Here we show that ectopic overexpression of F5H in Arabidopsis abolishes tissue-specific lignin monomer accumulation. Surprisingly, overexpression of F5H under the control of the lignification-associated cinnamate-4-hydroxylase promoter, but not the commonly employed cauliflower mosaic virus 35S promoter, generates a lignin that is almost entirely comprised of syringylpropane units. These experiments demonstrate that modification of F5H expression may enable engineering of lignin monomer composition in agronomically important plant species.