Acetate-free biofiltration versus bicarbonate haemodialysis in the treatment of patients with diabetic nephropathy: a cross-over multicentric study

BACKGROUND: Recent evidence suggests that the spinal cord is an important site of anesthetic action that produces surgical immobility. Inhalation anesthetics depress the Hoffmann's reflex (H reflex) and F wave, indicating spinal motoneuron suppression. The aim of this study was to assess the correlation between isoflurane-induced immobility and H- and F-wave suppression. METHODS: The baseline H reflex and F wave were measured before anesthesia in 15 adult patients. After induction, 1% end-tidal isoflurane was maintained for 20 min before the H and F waves were reelicited. Using an electric stimulus applied to the forearm and grading the response as movement or no movement, the authors increased or decreased the isoflurane concentration in 0.1% steps, depending on the movement responses. The H and F waves were recorded 20 min after each change of isoflurane concentration. The correlation between H- and F-wave suppression and surgical immobility was analyzed using a paired t test with Bonferroni correction. RESULTS: H-reflex amplitude (2.74 +/- 1.63 mV) and F-wave persistence (70.69 +/- 26.19%) at the highest isoflurane concentration that allowed movement response to a stimulus are different (P < 0.01) from these (1.97 +/- 1.46 mV; 43.16 +/- 22.91%) at the lowest isoflurane concentration that suppressed response. At 0.8% isoflurane, the H-reflex amplitude was 3.69 +/- 1.83 mV with movement and 1.01 +/- 1.14 mV without movement (P < 0.01); F-wave amplitude was 0.29 +/- 0.15 mV with movement and 0.11 +/- 0.06 mV without movement (P < 0.01); F-wave persistence was 80 +/- 22.36% with movement and 34.9 +/- 25.75% without movement (P < 0.01). CONCLUSIONS: The degree of H- and F-wave amplitude and F-wave persistence suppression correlates with movement response, suggesting that isoflurane-suppressive action in the spinal cord plays a significant role in producing surgical immobility.     

Changes in the excitability of soleus muscle short latency stretch reflexes during human hopping after 4 weeks of hopping training

Changes in the excitability of the human triceps surae muscle short latency stretch reflexes were investigated in six male subjects before and after 4 weeks of progressive two-legged hopping training. During the measurements the subjects performed 2-Hz hopping with: preferred contact time (PCT) and short contact time. The following reflex parameters were examined before and after the training period: the soleus muscle (SOL) Hoffmann-reflex (H-reflex) at rest and during hopping, the short latency electromyogram (EMG) components of the movement induced stretch reflex (MSR) in SOL and medial gastrocnemius muscle (MG), and the EMG amplitude of the SOL and MG tendon reflexes (T-reflexes) elicited at rest. The main results can be summarized as follows: the SOL T-reflex had increased by about 28% (P < 0.05) after training while the MG T-reflex was unchanged; the SOL MSR (always evident) and the MG MSR (when observable) did not change in amplitude with training, and before training the SOL H-reflex in both hopping situations was significantly depressed to about 40% of the reference value at standing rest (P < 0.05). After training the H-reflex during PCT hopping was no longer depressed. As the value of the measured mechanical parameters (the total work rate, joint angular velocity and the ankle joint work rate) was unchanged after training in both hopping situations, the reflex changes observed could not be ascribed to changes in the movement pattern. To explain the observed changes, hypotheses of changes in the excitability of the stretch reflex caused by the training were taken into consideration and discussed.     

Sensitivity of H-reflexes and stretch reflexes to presynaptic inhibition in humans

The sensitivity of soleus H-reflexes, T-reflexes, and short-latency stretch reflexes (M1) to presynaptic inhibition evoked by a weak tap applied to the biceps femoris tendon or stimulation of the common peroneal nerve (CPN) was compared in 17 healthy human subjects. The H-reflex was strongly depressed for a period lasting up to 300-400 ms (depression to 48 +/- 23%, mean +/- SD, of control at a conditioning test interval of 70 ms) by the biceps femoris tendon tap. In contrast, the short-latency soleus stretch reflex elicited by a quick passive dorsiflexion of the ankle joint was not depressed. The soleus T-reflex elicited by an Achilles tendon tap was only weakly depressed (92 +/- 8%). The H-reflex was also significantly more depressed than the T-reflex at long intervals (>15 ms) after stimulation of CPN (H-reflex 63 +/- 14%, T-reflex 91 +/- 13%; P < 0. 01). However, the short-latency (2 ms) disynaptic reciprocal Ia inhibition evoked by stimulation of CPN was equally strong for H- and T-reflexes (H-reflex 72 +/- 10%, T-reflex 67 +/- 13%; P = 0.07). Peaks in the poststimulus time histogram (PSTH) of the discharge probability of single soleus motor units (n = 53) elicited by an Achilles tendon tap had a longer duration than peaks evoked by electrical stimulation of the tibial nerve (on average 5.0 ms as compared with 2.7 ms). All parts of the electrically evoked peaks were depressed by the conditioning biceps femoris tendon tap (average depression to 55 +/- 27% of control; P < 0.001). A similar depression was observed for the initial 2 ms of the peaks evoked by the Achilles tendon tap (69 +/- 48%; P < 0.001), but the last 2 ms were not depressed. Conditioning stimulation of the CPN at long intervals (>15 ms) also depressed all parts of the electrically evoked PSTH peaks (n = 34; average 65%; P < 0.001) but had only a significant effect on the initial 2 ms of the peaks evoked by the Achilles tendon tap (85%; P < 0.001). We suggest that the different sensitivity of mechanically and electrically evoked reflexes to presynaptic inhibition is caused by a difference in the shape and composition of the excitatory postsynaptic potentials underlying the two reflexes. This difference may be explained by a different composition and/or temporal dispersion of the afferent volleys evoked by electrical and mechanical stimuli. We conclude that it is not straightforward to predict the modulation of stretch reflexes based on observations of H-reflex modulation.     

Experimental muscle pain increases the human stretch reflex

In this study we investigated the effect of human experimental muscle pain on H- and stretch reflexes as indicators of changes in muscle spindle sensitivity. Fourteen healthy, male volunteers participated in the study. Muscle pain was produced by infusion of 5% hypertonic saline over a period of 10-15 min in m. soleus and in m. tibialis anterior. Reflexes were elicited in the relaxed and active soleus muscle (10-15 Nm ankle torque) before, during and after muscle pain. Control measurements were made with infusions of 0.9% isotonic saline. Surface electromyograms (EMG) were measured from the soleus muscle, and torque was measured from the ankle joint. With pain in the soleus muscle the mechanical stretch reflex response (ankle torque) increased significantly (P = 0.0007) as compared to before pain. With pain in the tibialis anterior muscle both the mechanical and EMG responses increased significantly (P = 0.001; P = 0.0003) as compared to before pain. The H-reflex showed no significant changes during the infusions in either muscles. This study has demonstrated a muscle pain-related increase in the amplitude of the stretch reflex without a corresponding increase in the H-reflex amplitude. One explanation could be an increased dynamic sensitivity of the muscle spindles during muscle pain caused by an increased firing rate in the dynamic gamma-motoneurones. However, the data could not support the vicious cycle model because the excitability of the alpha-motoneurone pool was unchanged.     

Return to work after laparoscopic cholecystectomy

Hoffmann's reflex or H-reflex (HR) is an electrically elicited reflex that measures excitability of motoneurons and shares some physiologic properties with the deep tendon reflex. Children with tendon hyperreflexia due to cerebral palsy usually have higher amplitude HRs. Nitrous oxide (N2O) depresses the HR in patients with normal spinal reflexes, although the effect of N2O in conditions with hyperreflexia such as cerebral palsy is not known. We propose to determine the effect of N2O on the amplitude of the HR under general anesthesia in children with hyperreflexia due to cerebral palsy. We studied eight children undergoing selective dorsal rhizotomy (SDR) for the relief of spasticity. The maximum amplitudes of the HR (HRmax) and direct motor response (MRmax) were routinely evoked under the following anesthetic conditions: 1) sufentanil and 66% N2O/33% oxygen; and 2) sufentanil and 100% oxygen. The HRmax amplitude was significantly lower when N2O was part of the inspired gas mixture. The differences between the no N2O and the 66% N2O groups were significant. The MRmax did not change significantly. Abnormal spinal reflexes seen in spastic diplegia can be abolished by inhaled N2O. This finding also suggests that N2O-induced depression of spinal reflexes should be a consideration during physiologic monitoring of the spinal cord under general anesthesia.     

The contribution of lipids and lipid metabolism to cellular functions of the Golgi complex

This purpose of this study was to clarify the relationship between segmental reflex excitability and posture and to investigate potential mechanisms responsible for modulation of the H-reflex (HR) in unsupported standing. Soleus (S) and lateral gastrocnemius (LG) HRs were recorded from subjects (N=12S, N=11LG) while their static posture was altered from supine to vertical (5 positions). This was compared to an unsupported standing position in which the subjects naturally underwent a small degree of postural sway, a dynamic posture condition. Although individual profiles suggested varied relationships between the S and LGHR and the angle of body tilt, the group data did not reveal significant differences. There was, however, a significant (p < .01) decrease in the S (43% 49%) and LG (34%-46%) HR when subjects stood without support compared to all static postures. This decrease occurred even though the tonic or background activity of the S and LG was present only when subjects were free standing. To determine whether weight-bearing was responsible for the HR depression, 3 additional conditions were compared (N=3), supported standing without weight-bearing (90 degrees NWB), supported standing with weight-bearing (90 degrees WB), and free standing. Again, S and LGHRs were depressed only when subjects were free standing. Presynaptic inhibition presumably accounts for the depression of the HR in unsupported standing. Data from 8 of the subjects were collected under the same 6 conditions using a shorter interstimulus interval (1 Hz stimulus instead of 0.1 Hz) which produced low frequency depression (LFD) of the S and LG HR. LFD reduced the amplitude of the S HR an average of 43% (p < .05) when subjects were in a supported static position but only 21% when subjects were free standing. Although tonic activity of the S was present only when subjects were free standing, in 2 (of 8) individuals the EMG in free standing was not measurably different from static conditions. In these individuals, free standing still depressed the SHR by 35%; however, the shorter stimulus interval now produced the same degree of LFD when subjects were free standing (35%) as when they were standing with support (37%). The data suggest that 2 presynaptic mechanisms, although independent, interact to control spindle afferent feedback when subjects are free standing. Postural sway appears to be necessary to reduce the gain of the HR when subjects are standing, whereas, LFD is influenced by the degree of muscle activation.     

Sensitive and rapid bioassay for analysis of P-glycoprotein-inhibiting activity of chemosensitizers in patient serum

The quantitative differences among individuals in the natural reciprocal inhibition of the soleus H-reflex during dorsiflexion were examined, in conjunction with the maximal H-reflex as the test reflex size in each individual. Maximal H-reflex was expressed relative to the maximal M-response (H(max)) when compared among individuals. Analysis showed that with increases in H(max) at rest in each individual, the inhibitory effect was first enhanced, then reached a peak, and was finally alleviated. This pattern was similar to the intraindividual pattern of the inhibitory effect induced by specific conditioning stimulus as a function of the test reflex size.     

123I-MIBG myocardial scintigraphy in diabetic patients: relationship with 201Tl uptake and cardiac autonomic function

The purpose of this study is to investigate the effects of aging on the human stretch reflexes. The EMG and torque responses of the stretch reflex of the wrist flexors were evoked by ramp-and-hold mechanical perturbations. The stretch reflexes were recorded at seven test conditions with different stretch velocity and muscle preload. The test results from young and older healthy adult subjects were compared. In average, the absolute amplitude of the short-latency (20-40 ms) EMG (recorded from flexor carpi radialis) reflex response was significantly lower in the older group. If the data were normalized and expressed in percentage of the maximal voluntary EMG activity, however, this group difference was not significant. There was no change in the reflex gain of the short-latency reflex with aging. For the long-latency (50-90 ms) EMG reflex response, both the normalized amplitude and the reflex gain were significantly enhanced with aging, probably through supraspinal mechanisms. There was no significant difference in the threshold velocity for the evoked EMG reflexive activities between age groups. There were also no changes in the reflexive wrist flexion torque with aging. These results suggested that the number of motor units recruited during the stretch reflex activity declined with aging although the percentage of motor units recruited was not affected by aging. It is concluded that the central regulating mechanisms of the spinal motoneuron excitability are not compromised by aging. The automatic gain compensation phenomenon is also preserved with aging.     

Changes in neural modulation and motor control during voluntary movement of older individuals

BACKGROUND: Changes in the modulation of soleus alpha motoneuron excitability, as assessed by H reflexes, and temporal sequencing of the soleus and tibialis anterior muscles during voluntary ankle dorsiflexions and plantar flexions of young (24.7 +/- 11.5; n = 13) and older (68.7 +/- 5.4; n = 13) subjects were assessed to determine potential neural mechanisms that might contribute to motor control changes associated with aging. METHODS: A repetitive stimulation (5 Hz) soleus H-reflex testing protocol and surface electromyography (EMG) were used to assess the latencies of soleus H-reflex changes in relation to tibialis anterior and soleus EMG activations of standing subjects during voluntary ankle dorsiflexions and plantar flexions at self-selected speeds. The pattern and latency of H-reflex changes in relation to EMG activity were compared between young and old subjects. RESULTS: There were no differences in the relative amount of antagonist muscle (soleus) inhibition during voluntary ankle dorsiflexions between young and old subjects (26.4% and 27.2% decrease from resting H-reflex values, respectively). Older subjects, however, required additional time to achieve these levels of inhibition. Delays in the activation of soleus H reflexes during the plantar flexion task were also observed in older subjects. Older subjects also had considerable intra- and intersubject variability in muscle temporal sequencing patterns during ankle plantar flexions. CONCLUSIONS: Although older subjects exhibited similar relative levels of alpha motoneuron inhibition and excitation during voluntary movements, this modulation was delayed when compared to younger subjects. Temporal sequencing of distal muscle activations also appears to undergo change with aging.     

Effects of food consistency on the modulatory mode of the digastric reflex during chewing in freely behaving rabbits

Effects of food consistency on the mode of the phase-linked modulation in the digastric reflex amplitude were examined in naturally chewing rabbits. Two test foods with different textures (bread as a soft food, pellet as a hard food) were used. The digastric reflex was elicited by electrical stimulation (10 train pulses at 2 kHz) of the inferior alveolar nerve. The amplitude of the digastric reflex measured was divided into three categories depending on the chewing phases in which the stimulus was delivered and each value was compared with the control response obtained when the animal was resting. The reflex was strongly inhibited in the jaw-opening phase and no difference was observed in the inhibitory effect between the foods. In the jaw-closing phase, larger digastric reflexes than those in the opening phase were elicited with both foods. This was the case in both the fast-closing and slow-closing phases. Reflex amplitude was significantly larger during chewing of the hard food than the soft food and, thereafter, inhibition of the reflex was observed only during chewing of the soft food in the closing phase. The results suggest the following: (1) food consistency may affect the central mechanism which regulates the digastric reflex and (2) the reflex may contribute to the regulation of masticatory force during chewing particularly hard food.     

Development of arousal-modulated visual preferences in early infancy.

Looking preferences to visual temporal frequencies between 1 and 8 Hz were studied longitudinally at 3 ages (newborn, 1 month, 4 months; N?=?77) in 3 conditions: less aroused (after feeding), more aroused-internal (before feeding), and more aroused-external (after feeding with 8 Hz visual stimulation before each trial). Replicating and extending previous results, a strong interaction between arousal level and stimulus frequency was found at newborn and 1 month. Infants preferred faster stimuli when less aroused and slower stimuli when more aroused, with no differences between the 2 more aroused conditions even though produced by different operations. At 4 months, the interaction with arousal no longer existed; faster stimuli were preferred in all conditions. Thus, after the transition in visual behavior normally occurring at 2–3 months, arousal no longer played a major role, possibly as a result of emergent cortical sensory-specific attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microsurgical C-2 ganglionectomy for chronic intractable occipital pain

The P300 event-related brain potential (ERP) was elicited with visual stimuli using an oddball task in which the subjects made button press responses to discriminate target and standard stimuli. Each stimulus occurred randomly with a 0.50 probability, and 10 trial blocks were presented at 10-min inter-block-intervals (IBIs). P300 amplitude declined reliably across trial blocks, and an interaction between trial block number and electrode site was observed. No habituation effects were found for P300 latency or for N100, P200, or N200 amplitude. The results suggest that P300 amplitude from visual stimuli habituates when short IBIs and a sufficient number of trial blocks are employed. Theoretical implications are discussed with respect to attentional resource allocation and context updating.     

P300 habituation from visual stimuli?

The P3(00) event-related brain potential (ERP) was elicited with visual stimuli using an oddball task in which the subject indicated with a finger tap response the occurrence of a target stimulus that occurred randomly on 20% of the trials and refrained from responding to a standard stimulus. A total of six trial blocks were collected, with an equal number of artifact-free epochs averaged for both stimulus types. P3 amplitude from the target stimuli did not decrease across trial blocks; P3 amplitude from the standard stimuli did decrease across trial blocks. P3 latency from both the target and standard stimuli increased across trial blocks. No changes in amplitude or latency independent of the P3 effects were obtained for the other ERP components with trial block. The results suggest that P3 components elicited by visual stimuli do not readily habituate for actively discriminated target stimuli. The theoretical implications are discussed in the context of previous findings.     

Postexercise potentiation of the H-reflex in humans

Post-muscle activation effects on segmental reflexes reveal divergent results dependent upon the manner in which the muscle is activated. Electrically activating triceps surae invokes a potentiation of the Achilles' tendon reflex and the soleus (S) H-reflex termed posttetanic potentiation. In contrast, brief volitional activation produces a subsequent potentiation of tendon reflexes, whereas H-reflexes become depressed. PURPOSE: The present investigation explored the effect of an intense bout of volitional resistance exercise on the S and lateral gastrocnemius (LG) H-reflexes to determine if a potentiation of the H-reflex could be induced with physiological stimuli. METHODS: LG and S H-reflexes were obtained from 10 college age men and women before and after a vigorous bout (eight sets of 10 repetitions) of concentric-eccentric triceps surae exercise. RESULTS: Every subject displayed an initial depression of the LG (P < 0.01) and S H-reflex (P < 0.05) immediately postexercise, consistent with postactivation depression. As a group, there was a significant (P > 0.01) potentiation of the LG H/M ratio following the depression. Five of 10 subjects demonstrated this potentiation, which often lasted 10 min postexercise. The other five subjects displayed a longer and more profound early depression followed by a return to control levels. CONCLUSION: The data suggest that at least two overlapping processes are occurring, a brief depression followed by or superimposed over a longer lasting potentiation. Possible neural mechanisms and implications to strength training are discussed.     

Circadian modulation of the rat acoustic startle response.

The acoustic startle response (ASR) of male rats was measured during several sessions over a 24-hr period in both a light–dark cycle and a constant-dark condition. Each session consisted of 10 trials each at 80, 90, 100, 110, and 120 dB white noise. The results indicate robust daily and circadian modulation of ASR amplitude that consist of an approximately 2-fold nocturnal increase at eliciting-stimuli intensities above 80 dB. Similar results were observed in female rats in constant-dark conditions. To determine whether daily changes in auditory thresholds were responsible for the observed modulation, ASR reflex modification procedures were used. These procedures were designed to measure auditory thresholds at frequencies of 10 and 40 kHz at several times of day. The results suggest a lack of significant circadian differences in auditory thresholds at these frequencies. This study demonstrates a novel role of the rat circadian system in the modulation of ASR amplitude. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of exposure to hypoxia on the signal-averaged electrocardiogram in healthy subjects

The effects of hypoxia on the signal-averaged ECG (SAECG) were investigated in 26 healthy active subjects with no suggestion of cardiac disease. The SAECG was recorded in each resting subject in normoxic and hypoxic normobaric conditions (inspired O2 fraction 20.7 vs 10.0%) which lowered resting arterial O2 saturation from 98.6 +/- 0.6% to 77.7 +/- 8%. Recordings from four subjects (three men) met the definition of abnormal late potentials at baseline; in all these subjects but one, who exhibited an improved but still abnormal QRS duration, these parameters returned to normal in hypoxic conditions. The duration of the filtered QRS was significantly reduced (from 107.6 +/- 13.2 to 101.6 +/- 11.3 ms, P < 0.01), the duration of the low amplitude signals in the terminal portion of the QRS < 40 microV (LAS) significantly decreased (from 26.5 +/- 9.5 to 22.7 +/- 7.9 ms, P < 0.05) and the root mean square voltage in the last 40 ms (Term-RMS) increased non-significantly (from 55.8 +/- 40.2 to 69.1 +/- 38.3 microV, P = 0.058). Hypoxia determined a higher (P < 0.05) heart rate increase in subjects with abnormal records than in normal subjects. These data could be related to a sympathic discharge. They suggest that: (1) variation in heart rate could affect the SAECG; (2) exposure to hypoxia improves SAECG parameters in healthy subjects, possibly related to sympathetic discharge; (3) abnormal records collected during sinus bradycardia could represent a type of false-positive expression of late potentials in young active adults.     

An intragenic suppressor of cold sensitivity identifies potentially interacting bases in the peptidyl transferase center of Tetrahymena rRNA

The effect of adrenoceptor activation on pharmacologically isolated monosynaptic inhibitory postsynaptic currents (IPSCs) detected in layer V pyramidal neurons was examined by using whole cell voltage-clamp in a slice preparation of rat sensorimotor cortex. Epinephrine (EPI; 10 muM) reversibly altered the amplitude of evoked IPSCs (eIPSCs) in slices from postnatal day 9-12 (P9-12) and P15-18 rats. The effects of EPI were heterogeneous in both age groups, and in individual cases an enhancement, a depression or no effect of eIPSCs was observed, although depression was observed more commonly in the younger age group. The effects of EPI on eIPSC amplitude were likely mediated through presynaptic mechanisms because they occurred in the absence of any alteration in the current produced by direct application of gamma-aminobutyric acid (GABA), or in input resistance. EPI always elicited an increase in the frequency of spontaneous IPSCs (sIPSCs) irrespective of whether or not it induced any change in the amplitude of eIPSCs in the same neuron. The increase in sIPSC frequency was blocked by phentolamine (10 muM) but not by propranolol (10 muM), supporting the conclusion that EPI-mediated effects on sIPSC frequency result from activation of alpha-adrenoceptors located on presynaptic inhibitory interneurons. In a subpopulation of neurons (3/9) from P15-18 rats, EPI increased both the amplitude and frequency of miniature IPSCs (mIPSCs) recorded in the presence of tetrodotoxin (TTX) and under conditions where postsynaptic EPI effects were blocked, suggesting activation of adrenoceptors on presynaptic terminals in these cells. Results of these experiments are consistent with an action of EPI at adrenoceptors located on presynaptic GABAergic interneurons. Adrenergic activation thus has multiple and complex influences on excitability in cortical circuits, some of which are a consequence of interactions that regulate the strength of GABAergic inhibition.     

Soleus H-reflex tests and clinical signs of the upper motor neuron syndrome

Soleus H-reflex tests are used for elucidating pathophysiological mechanisms in motor control. The cumulative vibratory inhibition of the soleus H-reflex, the ratio of the reflex to direct muscle potential (H to M ratio) and the recovery curve of the soleus H-reflex were studied in 38 patients with varying signs of the upper motor neuron syndrome for a possible relation with clinical features. The results were compared with those obtained from a group of healthy volunteers. The magnitude of vibratory inhibition decreased with increase of hypertonia. The H to M ratio increased as the activity of the tendon reflex was enhanced and correlated to a lesser degree with muscle tone. Both the H to M ratio and late facilitation of the soleus H-reflex recovery curve were elevated in clonus. The findings suggest that alterations in the results of soleus H-reflex tests relate to specific clinical features of the upper motor neuron syndrome. Possible pathophysiological implications are discussed.     

An evaluation of three neuroleptanalgesic combinations in rabbits

In this study, novel combinations of analgesics and neuroleptics were used in the rabbit in an attempt to produce a surgical level of anesthesia. A commercially available mixture of fentanyl (0.06 mg/kg) and droperidol (3.0 mg/kg; F/D) was evaluated alone and in combination with either the benzodiazepine derivative, diazepam (2 mg/kg) or the alpha-2 adrenoceptor agonist, detomidine (20 micrograms/kg). Rabbits were anesthetized on consecutive weeks with one of the three regimens. Heart rate, respiratory rate, blood pressure, and arterial blood gases (pH, PCO2, PO2) were measured throughout each trial. The times of loss and return of palpebral, righting, and pedal reflexes were recorded. The addition of diazepam to the F/D combination caused marked prolongation of the duration of reflex loss for all reflexes. If the duration of reflex loss for F/D is considered to be 100%, then F/D plus diazepam (F/D/diazepam) prolonged the duration of reflex loss to 547% and 204% for righting and pedal reflex, respectively. The combination of F/D/diazepam produced significantly different results from those for either of the other combinations for righting reflex and palpebral reflex. The results for F/D/diazepam were also markedly different from F/D for pedal reflex, but were not significantly different from those for F/D/detomidine. Prolongation of the duration of reflex loss was more moderate with the addition of detomidine (148% and 174% for righting and pedal reflexes, respectively). Reflexes persisted in some rabbits for each anesthetic regimen. Palpebral reflex was preserved in one of the rabbits given F/D/diazepam, four of five rabbits given F/D, and in two rabbits given F/D/detomidine.(ABSTRACT TRUNCATED AT 250 WORDS)     

Human in vivo somatic mutation measured at two loci: individuals with stably elevated background erythrocyte glycophorin A (gpa) variant frequencies exhibit normal T-lymphocyte hprt mutant frequencies

The P3 event-related potential (ERP) component was recorded from 7- to 18-year-old children of alcoholics (COAs, n = 50) and age- and sex-matched control children (n = 50) using a visual oddball paradigm, involving nontarget (76%), target (12%), and novel (12%) stimuli. Topographic maps of P3 and associated scalp current density were obtained to supplement a topographic profile analysis. COAs manifested a smaller amplitude P3 to target stimuli over the centroparietal, parietal, and occipital scalp locations than controls. Also, COAs exhibited a smaller amplitude P3 to novel stimuli over the occipital scalp than controls. There were no significant differences between COAs and controls in the P3 scalp topography, indicating that differences in intracranial source strength rather than in source configuration were responsible for the between-group amplitude differences. Also, no significant group differences were observed in the P3 peak latency or in behavioral performance. These results support the notion that the visual P3 may provide a vulnerability marker of alcoholism.