Biomedical subjects
Publications and source records attributed to S Hawkins.
Using sequence-specific oligonucleotide probes, no altered distribution in the frequency of HLA-DPB1 alleles was found in multiple sclerosis patients from Northern Ireland. Although present in the controls, linkage disequilibrium between HLA-DPB1*0101 and HLA-DR17 was not found in multiple sclerosis patients.
DNA from multiple sclerosis (MS) patients and healthy control individuals from the Northern Ireland population, was assessed by restriction fragment length polymorphism (RFLP) analysis to look for disease-associated polymorphisms. HLA-DR and -DQ allogenotyping was performed using a single enzyme (TaqI)/Multiple probe system. The TaqI/DR beta RFLPs correlate well with serologically defined specificities and in addition detect further subtypes of these associated with DQ or Dw specificities. The results confirm an association of MS with DR beta 15 and show a decreased frequency of DR beta 4 in the patients. An increased frequency of DR beta 17 in patients negative for DR beta 15 was also found. There is a decrease in the frequency of the TaqI/DQ beta 3 (TA10 + ve) RFLP and the TaqI/DQ alpha 2LL genotype in the MS patients, these not being associated with DR beta 15. In addition RFLP analysis of the DPA1 and DPB1 genes reveals an MspI/DP beta 3.0-kb fragment which occurs at a higher frequency in the patients than in the controls.
Very low birthweight (VLBW) is often considered to be a risk factor for speech and language disorders, yet data are equivocal. The present study compared speech and language comprehension and production between 249 very-low-birthweight (VLBW: less than 1.5 kg) and 363 normal-birthweight 8-year-olds, randomly sampled in a geographic area. Mean performance for the entire group of VLBW children and for the group when 24 VLBW children with major neurologic abnormalities were excluded, was significantly lower than for controls on the majority of speech and language measures. Further analyses addressed the clinical significance of these statistically significant differences. Test scores were converted to standard scores and grouped according to standard deviation intervals, thus portraying each child's performance in terms of the magnitude of discrepancy from each test's mean. When the 24 children with major neurological abnormalities were excluded, no significant differences between the VLBW and control children were observed. Using discrepancy between WISC-R performance IQ and language to define specific language impairment (SLI), a higher percentage of control than VLBW children were identified as having SLI. Neonatal risk factors did not differentiate between VLBW children with or without SLI. A higher proportion of VLBW than control children did present subnormal language associated with IQ less than 85, hearing deficits, and/or major neurological impairments. Thus, SLI is not more common among VLBW than control children. Language deficits accompanied by more general developmental problems, however, are more frequent.
A number of phosphoproteins were found in the soluble fraction of rat skeletal muscle by two-dimensional polyacrylamide gel electrophoresis (PAGE). The pattern of some of these phosphoproteins differed in fast (extensor digitorum longus, EDL) or slow (soleus) muscles, was dependent on normal innervation, and was altered with denervation. In order to determine if the pattern was maintained by electrical activity or trophic factors, we compared the effect of electrical block by local neural application of tetrodotoxin with the effect of complete nerve section. Both methods produced similar alterations in phosphoproteins, indicating that the pattern is dependent on nerve activity, not trophic factors. Such phosphoproteins are possible mediators of neural activity on gene expression.
Research indicates that, when the first and second formants of a vowel are separated by less than about 3.5 Bark, perception of its height and some other aspects of its quality is determined by some weighted average of the low-frequency spectrum, rather than by particular harmonic or hypothetical formant frequencies (as is the case with more widely spaced formants). This spectral averaging has been called the center of gravity (COG) effect. Although the existence of the effect is generally accepted, the factors that govern it are poorly understood. One possibility is that the influence of the spectral envelope on perceived vowel quality increases as low-frequency spectral prominences become less well defined. A series of three experiments examined this possibility in: (1) nasal vowels, where the lowest spectral prominence is broader and flatter than that of oral vowels; (2) one- versus two-formant vowels with bandwidths appropriate for oral vowels; and (3) two-formant vowels with very narrow or very wide bandwidths. The results of these experiments show that, when two or more spectral peaks lie within 3.5 Bark of one another, F1 and the centroid (an amplitude-weighted average frequency that estimates the COG in the low-frequency spectrum) roughly determine the boundaries within which the perceptual COG lies; the frequencies of spectral peaks dominate responses when formant bandwidths are narrow, whereas overall spectral shape exerts more influence when spectral prominences are wide. Assuming that all vowels undergo the same processing, it is suggested that vowel quality, particularly height, is determined both by the frequency of the most prominent harmonics in the low-frequency region and by the slopes of the skirts in the vicinity of these harmonics. These two effects are most clearly separable in vowels with poorly defined spectral prominences whose shape cannot be adequately described by specifying the frequencies and degree of prominence of just one or two harmonics, or hypothetical formant peaks.
Although endotracheal intubation is considered the optimal technique for airway management in critically ill patients, performance of this task in the prehospital setting is at times difficult due to increased masseter muscle tone, vocal cord spasm, or patient combativeness. Use of short-acting paralyzing agents by paramedics to facilitate intubation in these situations is an uncommon practice. We report the recent experience of an emergency medical service system that has used succinylcholine (SUX) for more than ten years. We reviewed prehospital patient intubations for two years; 215 patients were intubated by paramedics without the use of SUX and 95 patients were intubated with the use of SUX. The patient group intubated with SUX was characterized by a greater percentage of women (48% vs 35%; P less than .05), a higher mean Glasgow Coma Scale score (8.6 vs 3.4), fewer intubations for cardiac arrest (3% vs 81%), and more hospital survivors (58% vs 24%; P less than .005). The groups were not different with respect to mean age or frequency of trauma. Paramedics chose to use SUX in 69% of nonarrested patients requiring intubation. SUX-assisted intubation was used most often for the indications of airway protection and respiratory distress. Review of hospital records showed no difference between the groups for frequency of either aspiration pneumonia or mechanical ventilation in patients surviving to hospital admission. No patient receiving SUX required emergency cricothyrotomy, nor was esophageal intubation noted in either group. Succinylcholine-assisted intubation was used safely and selectively by the paramedics in this EMS system to permit airway control and ventilation of patients with more difficult intubations.
In 10 patients undergoing routine coronary artery surgery, plasma renin activity and vasopressin concentration were measured at intervals before the induction of anaesthesia, and for 6 h after bypass. In three patients plasma renin activity was increased, but the increases followed no particular pattern. Vasopressin concentrations increased in all 10 patients, but the changes were not significantly correlated with the postoperative arterial hypertension that was seen in seven of the patients.
Explore the source record for details and available documents.
A modification of the standard fusion methodology is described which results in greatly increased yields of monoclonal antibodies against certain organ-specific parasites. Several fusions were carried out using mice infected with Schistosoma mansoni or Nematospiroides dubius, using B lymphocytes harvested from either the spleen or the mesenteric lymph nodes. Results indicated a greatly improved yield of positive clones using the lymph nodes as a source of B cells for fusion. A 7-fold increase in the number of positive clones was seen with N. dubius injections, while S. mansoni fusions showed a 2-fold increase.
For each of five vowels [i e a o u] following [t], a continuum from non-nasal to nasal was synthesized. Nasalization was introduced by inserting a pole-zero pair in the vicinity of the first formant in an all-pole transfer function. The frequencies and spacing of the pole and zero were systematically varied to change the degree of nasalization. The selection of stimulus parameters was determined from acoustic theory and the results of pilot experiments. The stimuli were presented for identification and discrimination to listeners whose language included a non-nasal--nasal vowel opposition (Gujarati, Hindi, and Bengali) and to American listeners. There were no significant differences between language groups in the 50% crossover points of the identification functions. Some vowels were more influenced by range and context effects than were others. The language groups showed some differences in the shape of the discrimination functions for some vowels. On the basis of the results, it is postulated that (1) there is a basic acoustic property of nasality, independent of the vowel, to which the auditory system responds in a distinctive way regardless of language background; and (2) there are one or more additional acoustic properties that may be used to various degrees in different languages to enhance the contrast between a nasal vowel and its non-nasal congener. A proposed candidate for the basic acoustic property is a measure of the degree of prominence of the spectral peak in the vicinity of the first formant. Additional secondary properties include shifts in the center of gravity of the low-frequency spectral prominence, leading to a change in perceived vowel height, and changes in overall spectral balance.
This article summarizes State supplementation activities under SSI for 1975. It discusses changes in the State programs that occurred during 1975 and presents some comparisons with data for 1974--the initial year of the SSI program. A slight shift occurred in the distribution of recipients by eligibility category for Federal and State supplementation from 1974 to 1975. During 1975 a few States changed from Federal administration to State administration of their mandatory supplementation programs while a few others initiated or expanded their optional supplementation programs. Several States also increased their supplements during the year.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.