Toward a comprehensive theory of stuttering: a commentary.
Explore the source record for details and available documents.
Humans↗
Biomedical subjects
A Smith
Publications and source records attributed to A Smith.
Autonomic correlates of stuttering and speech assessed in a range of experimental tasks.
Electrodermal activity, peripheral blood flow, and heart rate were recorded from 19 stutterers and 19 normal speakers during performance of jaw movements, a strenuous breath-holding task, reading, and spontaneous speech. The tasks were selected to produce a range of autonomic activation and thus help scale autonomic activation for speech relative to other motor behaviors. Speaking was associated with relatively large increases in autonomic activity in both stutterers and normal speakers. There were no differences between the two groups of speakers, suggesting that the stutterers did not have abnormally high levels of autonomic activation in speech. Within the group of stutterers, the more extreme increases in arousal (specifically increases in measures reflecting sympathetic arousal) were correlated with the occurrence and increased severity of disfluent speech. Significant correlations were found for the intervals prior to, during, and after speech. Although significantly correlated with disfluency, measures of autonomic arousal accounted for small percentages of the variances of fluency and severity. The results are consistent with the hypothesis that sympathetic arousal accompanies the breakdowns in speech motor processes characteristic of stuttering. Mechanisms linking autonomic nervous system functions and somatic sensorimotor processes involved in speech production are discussed.
Adolescent↗
Exogenous magnesium chloride-adenosine triphosphate administration during reperfusion reduces the extent of necrosis in previously ischemic skeletal muscle.
The lower extremity may be exposed to prolonged periods of ischemia, resulting in depletion of intracellular energy stores in the affected skeletal muscle. The role of adenine nucleotide reduction and failure of resynthesis on reperfusion in determining the extent of muscle necrosis was investigated in this study, in addition to the possible beneficial effects of the addition of exogenous adenosine triphosphate-magnesium chloride during early reperfusion. The isolated paired canine gracilis muscle model was used. After 4 hours of normothermic ischemia in group I, a perfusate Krebs-Henseleit solution plus the gradual reintroduction of oxygenated blood flow was compared to standard reperfusion. In group II, a similar infusion protocol was used, with the addition of 2 mmol/L adenosine triphosphate-magnesium chloride and compared to normal reperfusion. Adenosine triphosphate-magnesium chloride resulted in the salvage of skeletal muscle, 57% +/- 12% versus 44% +/- 14% (p less than 0.05, n = 6 pairs). Reperfusion with the solution alone increased the resulting necrosis (42% +/- 13% vs 60% +/- 20%, n = 6 pairs). Adenine nucleotide stores were not increased, but oxygen consumption was increased by magnesium chloride-adenosine triphosphate (p less than 0.05, analysis of variance [ANOVA]). A clear relationship was demonstrated between the fall in energy stores, as measured by a change in energy charge potential from preischemia to end ischemia levels, and the extent of resulting necrosis (p less than 0.01). In summary, the addition of 2 mmol/L to an infusion of Krebs-Henseleit solution during reperfusion results in significant salvage of skeletal muscle.(ABSTRACT TRUNCATED AT 250 WORDS)
Adenine Nucleotides↗
The hypnotic relationship and the holographic paradigm.
The holographic paradigm is a recently constructed model of consciousness derived from neuropsychology and quantum physics. It views the processing of mental forms as occurring within the context of a part/whole relationship, where the identified part exists within the code of the whole. In this paper I have applied this paradigm to the hypnotic relationship, viewing the hypnotic process as an undulation of form and transitional states and proposing the holographic paradigm as a cutting edge to understand the curative processes in hypnosis.
Adult↗
The purification, characterization and role of the d-type cytochrome oxidase of Klebsiella pneumoniae during nitrogen fixation.
Klebsiella pneumoniae synthesized only b-type and d-type cytochromes under the wide range of growth conditions tested, and reaction with CO revealed two potential oxidases. The o-type oxidase was produced only in the presence of O2 and appeared to be repressed by glucose. The d-type oxidase was, by contrast, produced only in the absence of measurable O2 (less than 1 microM), and was the only oxidase expressed in nitrogen-fixing conditions. It was extracted from the membrane, purified and shown to be similar to that from E. coli in being a heterodimer (subunits of Mr 52,000 and 35,000), in containing two distinguishable b haems and haem d (one or two molecules per molecule of oxidase), and in being able to react with O2 to give a stable oxygenated intermediate. The purified d-type cytochrome oxidase had a very high affinity for O2 (Km 20 nM; measured by the spectral properties of leghaemoglobin). It is proposed that this provides a role for this oxidase in lowering the O2 concentration to allow nitrogenase synthesis and function, and to provide a terminal oxidase to permit electron-transport-coupled ATP synthesis which supports the increase in efficiency of nitrogen fixation observed under microaerobic conditions.
Amino Acids↗
Serum type III procollagen peptide, dynamic liver function tests and hepatic fibrosis in psoriatic patients receiving methotrexate.
The serum level of the aminoterminal peptide of type III procollagen (P3NP) was measured in 51 psoriatic patients on long-term, once weekly, low-dose methotrexate and in a control group of patients with extensive psoriasis who had never had systemic treatment. Serum P3NP levels were normal in all control patients, but were elevated in the majority of methotrexate-treated patients, even those with normal or non-specific liver histology. Although the highest P3NP values were found in the groups of patients with fibrosis and cirrhosis, isolated P3NP measurements did not discriminate between individuals with and without significant liver pathology. Neither standard nor dynamic liver function tests were able to identify patients with significant liver damage and in most cases results were in the normal range.
Adult↗
Mosaic acral keratosis.
We describe two patients with acral keratosis with a striking mosaic or jigsaw-puzzle pattern of keratotic papules on the dorsal aspects of the feet and adjacent parts of the legs. Both patients also showed mild diffuse palmoplantar keratosis and clavus-like lesions over the interphalangeal joints of the toes; one patient also had keratotic papules on the hands and hyperkeratotic plaques over the knees. The differential diagnosis of acral keratoses, including several recently described forms, is briefly discussed.
Adult↗
Two cases of cri-du-chat syndrome with mild phenotypic effect but with different size of 5p deletion.
The clinical and cytogenetic findings of two cases of cri-du-chat syndrome are described. Both cases were females with only slight growth delay, moderate mental disability and minimal phenotypic effects. The mild phenotype was difficult to correlate with the karyotype, which on GTG and RBG banding showed that each had a regular de novo 5p deletion. The deletion in Case 1 was terminal - 46,XX,del(5) (pter----p15.2:) and in Case 2 it was interstitial - 46,XX,del(5) (pter----p15.2::p13.3----qter). The deletion in Case 2 was considerably larger than in Case 1.
Child↗
Data on families of chromosome translocation carriers ascertained because of habitual spontaneous abortion.
Cytogenetic studies were performed on 1,180 individuals--490 couples + 200 females presenting with habitual spontaneous abortion (HSA). These revealed 24 abnormal results (2.03%)--15 were apparently balanced reciprocal translocations and 9 were Robertsonian translocations. Of 97 pregnancies among the translocation carriers, there were 10 living children and 87 pregnancy losses--a loss rate of 89.7%. There were 11 familial translocations. In 10 familial cases with a full family tree, there were 27 spontaneous abortions and 64 livebirths among the 30 adult translocation carrier relatives--a loss rate of 29.6%. This is twice the risk found in the general population but not as high as in the probands, who had 6 times the abortion rate in the general population. Mechanisms are suggested for this difference. The subsequent pregnancy history of 12 index translocation couples showed an apparently improved pregnancy outcome with 13 further fetal losses and 13 living children, over a follow-up time per patient ranging from 1-5.5 years. However, when the pregnancy losses at ascertainment were combined with postascertainment losses, the overall rate of pregnancy loss remained the same.
Abortion, Habitual↗
Cytogenetic studies in perinatal death.
Following tissue culture cytogenetic studies were performed on tissue obtained from 136 fetuses who died in the perinatal period (98 stillbirths and 38 neonatal deaths). The gestational age of the stillbirths was evenly distributed between 20 and 40 weeks (1 was 42 weeks) while 74% of the neonatal deaths were term babies. Analyzable metaphases were obtained in 45 stillbirth specimens (46%) and 32 neonatal specimens (84%). Abnormal karyotypes were identified in 7 of the stillbirths (15.5%) and 8 of the neonatal deaths (25%) and all these were from babies with congenital anomalies identified at autopsy. Time delays were crucial to the success of culture from stillbirths, but specimens obtained from neonatal deaths could be grown successfully up to 3 days after death. Generally the placenta was more viable than other tissues, including skin, cartilage and muscle. Whereas growth was obtained in 69% of fresh unexplained stillbirths, no tissue from the macerated stillbirths grew. This is a group which may have a high abnormality rate. We recommend that if fetal assessment during pregnancy suggests a compromised fetus and there are no maternal factors to account for this, an amniocentesis be performed.
Chromosome Aberrations↗
Air leaks and vasopressin release.
Eleven very low birthweight babies being ventilated for respiratory problems during the first week of life developed air leaks on 22 occasions. On 16 out of 19 occasions the infants showed increases in urinary excretion of vasopressin after these events and on 10 occasions out of 13 there was a rise in the plasma arginine vasopressin concentration. The peripheral signs of the syndrome of inappropriate antidiuretic hormone release were seen on only one occasion in response to the sometimes high vasopressin concentrations.
Arginine Vasopressin↗
Plasma concentration of atrial natriuretic peptide in spontaneous atrioventricular re-entrant tachycardias of childhood.
Plasma atrial natriuretic peptide was measured in 13 children between the ages of 1 week and 2 years 9 months during atrioventricular re-entrant tachycardia and 15 minutes after the restoration of sinus rhythm. There was a significant decline in atrial natriuretic peptide during sinus rhythm. Plasma concentrations of the peptide were significantly higher during tachycardia in seven infants under 1 year than in the six older children. The heart rates and the duration of tachycardia were not significantly different in the two age groups. Cardiac failure was present in five of seven children under 18 weeks of age during tachycardia but in none of the older children. The plasma concentration of atrial natriuretic peptide did not significantly correlate with duration of tachycardia or heart rate. If tachycardia occurs in young infants the low functional reserve capacity of the developing heart leads to cardiac failure more frequently and it is likely that this was the cause of the significantly higher plasma concentration of atrial natriuretic peptide in the younger children.
Adenosine↗
Occurrence of the alpha thalassaemia-mental retardation syndrome (non-deletional type) in an Australian male.
The rare association of alpha thalassaemia and mental retardation has been described previously. Molecular studies of the alpha globin cluster in these cases have been heterogeneous, with some patients having large deletions while in others the alpha globin complex appears to be intact (non-deletional). The non-deletional cases form a distinct group whose features include severe mental retardation, haematological changes of haemoglobin H (Hb H) disease, developmental defects, and unusual patterns of inheritance. To date, five cases have been described with non-deletional alpha thalassaemia-mental retardation. We present here a further example of a young male of Northern European origin who appears to have the non-deletional form of the disease. Clinical features included severe mental retardation, Hb H disease, and developmental defects similar to those reported previously. DNA mapping, including pulsed field electrophoresis, showed no evidence of deletions within the alpha globin cluster. Karyotypic analysis indicated an increase in random breakage, which has been observed previously in one case of deletional alpha thalassaemia-mental retardation. Profuse Hb H bodies and Hb H on electrophoresis were consistent with Hb H disease. However, the latter was present at a relatively low level (1.6%) and, as well, the mean corpuscular volume (82.8 fl) and mean corpuscular haemoglobin (26.4 pg) were surprisingly high. Our findings are compared to other cases described with the non-deletional Hb H-mental retardation syndrome.
Adult↗
Sensory and cognitive event-related potentials in myalgic encephalomyelitis.
Myalgic Encephalomyelitis (ME) is a form of post viral fatigue syndrome resulting in myalgia and fluctuating fatiguability. Symptoms reflecting central nervous system dysfunction are common and include muscle weakness, headache, sensory disturbances, poor short term memory and impairment of concentration. In view of the fact that sensory and cognitive disturbances are experienced by many patients objective evidence was sought with multi-modality sensory evoked potentials and auditory event-related cognitive potentials in a group of ME patients both with and without the enteroviral antigen, VP1 test positive. The auditory brainstem, median nerve somatosensory and pattern reversal checkerboard visual potentials were normal for all 37 patients tested. In contrast to the sensory potentials significant differences in the mean latencies of the cognitive potential N2 and P3 were found. Reaction times were also significantly prolonged but the performance in terms of error was not significantly affected. No significant difference emerged in any of the parameters for the VP1 test. P3 was abnormal in latency or amplitude in 36% of the VP1 positive patients for the frequency discrimination task and 48% for the more difficult duration discrimination task. The abnormalities indicate attentional deficits in some patients and slower speed of information processing in others. The prolonged latencies observed in these patients have not been observed in patients with depression in many other studies.
Adolescent↗
Complement activation and white cell sequestration in postischemic skeletal muscle.
After skeletal muscle ischemia, tissue damage is augmented during reperfusion. White blood cells (WBCs) and complement proteins may participate in the reperfusion injury. The purpose of this study was to define the kinetics of classical and alternative pathway complement activation and WBC sequestration by postischemic skeletal muscle during the first 48 h of reperfusion in vivo. The isolated canine gracilis muscle model was used. Systemic levels of the complement proteins factor B (alternative pathway) and C4 (classical pathway) were quantitated by hemolytic assay. WBC sequestration was measured by gracilis arterial-venous WBC differences and tissue myeloperoxidase activity. Reperfusion was associated with an 18% decrease in systemic factor B levels but no consistent change in systemic C4 levels. WBCs were sequestered during the first 4 h of reperfusion, and tissue myeloperoxidase activity was elevated 97-fold after 48 h of reperfusion. These results suggest that skeletal muscle ischemia-reperfusion stimulates 1) activation of the alternative but not the classical complement pathway and 2) an immediate and prolonged sequestration of WBCs.
Animals↗
High-frequency oscillations as indicators of neural control mechanisms in human respiration, mastication, and speech.
1. Electromyograms (EMGs) were recorded from the right and left ventrolateral surfaces of the chest wall to study the activity of the diaphragm during three tasks: moderately deep breathing, speech production, and speechlike breathing in which subjects mimicked their speech breathing pattern but did not vocalize. In a second experimental protocol, activity of right and left masseter muscles was recorded in three conditions: chewing, rhythmic clenching, and speech. 2. EMGs were analyzed in the frequency domain by computing the average spectrum of 128-ms intervals selected from the rising phase of the EMG in 30 repetitions of each task. Coherence functions between bilateral pairs of EMGs were computed and examined for significant coherence in the range of 20-230 Hz. 3. In the deep breathing condition, significant coherence was present in two ranges, 20-60 Hz and 60-110 Hz. Oscillations in the 60- to 110-Hz range have long been associated with the operation of the primary respiratory pattern generator, and the present results replicate earlier reports of correlated oscillations in this range in bilateral recordings of human respiratory muscles during voluntarily controlled breathing. 4. In speech and speechlike breathing, correlated oscillations in the 60- to 110-Hz range were significantly reduced. This result supports the hypothesis that the neural circuitry characterized by high-frequency oscillations (HFOs) in the 60- to 110-Hz range, possibly a central pattern generator (CPG), is not the primary source of drive to respiratory motoneuron pools in speech. 5. During chewing, highly correlated oscillations were observed in right and left masseter activity. Significant coherence occurred in the range of 20-140 Hz, with very large peaks in the 20- to 60-Hz band. This result is interpreted in light of studies of rhythmic jaw movements elicited by cortical stimulation in experimental animals and studies of the reflex organization of the jaw-closing muscles. It is possible that highly correlated oscillations in the 20- to 60-Hz band arise from a central command system, such as a pattern generator, from reflexes, or from an interaction of central and reflex inputs. 6. In most subjects, nonzero coherence in the 20- to 60-Hz band also was observed during clenching and speech; however, levels of coherence in the 20- to 60-Hz band were significantly reduced in these conditions compared with chewing. 7. Taken together, the present results suggest that coherent HFOs observed in consistent frequency ranges across subjects are characteristic of human motor behaviors that are likely to involve pattern generation circuitry.
Adult↗
Trends in the organization of cervical cancer screening.
Cervical cytological screening has been available in the UK for several decades, but has not achieved a significant reduction in the incidence of and mortality from cervical cancer. In this paper we describe past problems of cervical screening, discuss the impact of recent innovations to computerize call and recall, and suggest further improvements for the future.
Appointments and Schedules↗
Localization and cure of epileptic foci, with the use of MEG measurements.
Explore the source record for details and available documents.
Electroencephalography↗