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Biomedical subjects

S Hawkins

Publications and source records attributed to S Hawkins.

At least 55 records · Page 3Linked to original sources
PubMed1996

Feeding interactions in infants with very low birth weight and bronchopulmonary dysplasia.

Infants with very low birth weight (VLBW) are at increased risk for feeding disorders that can affect growth and development. One hundred and forty one mother-infant pairs were compared [55 with infants with high medical risk due to infant VLBW and bronchopulmonary dysplasia (BPD), 34 VLBW without BPD, and 52 term infants] on operationally defined measures of feeding behaviors and maternal self-report of depression and anxiety. Mothers of VLBW infants with and without BPD spent more time prompting their infants to feed when their infants engaged in nonfeeding behavior. Despite increased maternal efforts, infants with BPD took in less formula, spent less time sucking, and spent a greater proportion of time nonfeeding. VLBW infants without BPD were equivalent to term infants in percentage of time sucking and in volume of formula ingested and were more likely to take in higher calories than infants with BPD. Mothers of VLBW infants with and without BPD were also more likely to report clinically significant symptoms of depression and anxiety than mothers of term infants. Because mothers of VLBW infants who were more depressed or anxious were less likely to verbally prompt their infants to eat, maternal psychological symptoms should be considered in assessing interactions of VLBW mother-infant dyads.

Adult↗
PubMed1995

Pain responses of hospitalized neonates to venipuncture.

Neonates' response to pain after venipuncture was studied by observing, recording, and measuring physiological and behavioral responses. The measurement used was the National Individualized Developmental Care Assessment Program (NIDCAP). Data were recorded from a convenience sample of 30 neonates required to have a venipuncture as part of their routine treatment for 20 minutes before and 20 minutes following the procedure by a person certified as reliable in administering the NIDCAP. Both behavioral and physiologic changes were observed. Most of the infants (93 percent) moved abruptly into a hyperalert or crying state in response to venipuncture, skipping several states without transition and showing disorganized behavior. The heart rate, oxygen saturation, and skin color showed significant changes when data recorded just prior to venipuncture were compared to data recorded immediately following the procedure. Nursing implications, including the unit environmental elements, are discussed.

Bloodletting↗
PubMed1994

TAP1 and TAP2 polymorphism in multiple sclerosis patients.

The frequency of TAP1 and TAP2 gene polymorphisms in MS patients was compared with that of a normal population. A significant increase in TAP2-379-VAL homozygosity and TAP2-565-ALA homozygosity was found in HLA-DRB1*1501-DQB1*0602-negative patients.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Increased incidence of intraventricular hemorrhage and developmental delay in cocaine-exposed, very low birth weight infants.

This study sought to determine whether very low birth weight (VLBW) infants (< 1500 gm) with fetal cocaine exposure differed from non-cocaine-exposed VLBW infants in incidence of neonatal medical complications and in later developmental outcome. Forty-one cocaine-exposed, VLBW infants, followed in a longitudinal study, were compared with 41 non-cocaine-exposed, VLBW infants of comparable race, social class, age, and incidence of bronchopulmonary dysplasia. Cocaine-exposed infants were identified on the basis of combined findings of maternal and/or infant urine immunoassay and on the basis of maternal self-report. At birth, groups did not differ on medical risk factors except that cocaine-exposed infants had a higher incidence of mild (grades I to II) intraventricular hemorrhage. Cocaine-using women were also more likely to use other drugs, especially alcohol, marijuana, and tobacco. At follow-up, at mean corrected ages of 16.5 +/- 8 months for 30 cocaine-exposed infants and 18.5 +/- 7 months for 37 non-cocaine-exposed infants, standardized assessments of cognitive (Mental Development Index) and motor (Psychomotor Development Index) development were administered. Cocaine-exposed infants had lower mean cognitive (83 +/- 27 vs 91 +/- 19), and motor (85 +/- 25 vs 96 +/- 18) scores; the incidence of developmental delay was significantly higher even after control for the effects of intraventricular hemorrhage and chronologic age. Cocaine-exposed VLBW infants were also more likely to be living with relatives or in foster homes. We conclude that these VLBW, cocaine-exposed infants were at increased risk of intraventricular hemorrhage, were more likely to be placed outside maternal care, and had higher incidences of cognitive and motor delays at follow-up.

Adult↗
PubMed1994

Ultrastructural pathology of an inherited lower motor neuron disease of pigs.

The ultrastructural features of a recently described inherited lower motor neuron disease were studied in 5 affected pigs. Clinical signs comprised progressive ataxia and paresis of variable severity. Affected pigs, 6, 7, 15, 15, and 19 weeks of age, and 2 unrelated healthy pigs, 9 and 15 weeks of age, were anesthetized and their tissues were fixed by whole body perfusion with mixed aldehydes. From 1 or more affected pigs, samples of cervical and lumbar spinal ventral horn, lateral and ventral spinal columns, dorsal and ventral lumbar spinal nerve roots, 2 peripheral nerves (Nn. phrenicus and fibularis communis), and 2 skeletal muscles (Mm. diaphragma and tibialis cranialis) were examined ultrastructurally. There was widespread degeneration of myelinated axons in peripheral nerves and in lateral and ventral columns of lumbar and cervical segments of spinal cord. Axonal degeneration was present in ventral spinal nerve roots and was absent in dorsal spinal nerve roots sampled at the same lumbar levels. Unmyelinated axons in peripheral nerves and spinal nerve roots were unaffected. In 4 of 5 affected pigs, there were atrophic alpha motor neurons in cervical spinal cord that contained dense, round osmiophilic perikaryal inclusions up to 4 microns in diameter and round swollen mitochondria. Axonal regeneration was present in N. phrenicus of the 19-week-old affected pig that had clinical signs of longest duration (10 weeks). There was no morphologic evidence of axonal degeneration or spinal neuronal atrophy in either control pig. The ultrastructural features of this motor neuron disease distinguish it from other reported progressive spinal neuropathies of pigs.

Animals↗
PubMed1991

HLA-DR and DQ DNA genotyping in multiple sclerosis patients in Northern Ireland.

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.

Gene Frequency↗
PubMed1991

Very-low-birthweight children and speech and language development.

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.

Chi-Square Distribution↗
PubMed1990

Effect of neural activity on skeletal muscle phosphoproteins.

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.

Animals↗
PubMed1990

The influence of spectral prominence on perceived vowel quality.

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.

Adolescent↗
PubMed1989

The Maine State Patient Education Forum: networking system for a rural area.

Patient education councils are growing and prospering. The Maine State Patient Education Forum is one such council which has gone through a continuing developmental process to meet needs of patient educators in Maine. Involving many organizations and individuals who do patient education, having a clear direction and a common locus, scheduling regular meetings, and participating in national networking have all been ways to vitalize and strengthen the council. Maine as a rural state has found the forum to be a dynamic model to motivate patient educators to maintain flexibility and acquire new concepts so they can continue to provide high quality patient education services.

Health Planning Councils↗
PubMed1988

Succinylcholine-assisted intubations in prehospital care.

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.

Adolescent↗
PubMed1986

Changes in pressor hormone concentrations in association with coronary artery surgery. Renin and vasopressin responses.

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.

Adult↗
PubMed1985

Improved methodology for the production of monoclonal antibodies against parasites.

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.

Animals↗
PubMed1985

Acoustic and perceptual correlates of the non-nasal--nasal distinction for vowels.

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.

Humans↗
PubMed1984

Catalytic site of calmodulin-dependent protein phosphatase from bovine brain resides in subunit A.

The calmodulin-dependent protein phosphatase from bovine brain is composed of two subunits: subunit A, Mr 60,000, and subunit B, Mr 16,500. Using in vitro immunization techniques, we have produced a monoclonal antibody specific for the phosphatase. The antibody was immobilized to Sepharose 4B to prepare an immunoabsorbent column, which was used to purify the enzyme. Phosphatase isolated from the column showed a polypeptide with Mr 60,000, equivalent to subunit A, which showed calmodulin-dependent phosphatase activity. Subunit B was not obtained from the column. Limited trypsin digestion stimulated phosphatase activity, yielding polypeptides of Mr 59,000, 43,000, and 16,000; the phosphatase activity after trypsin digestion was calmodulin independent. Chromatography of trypsin-treated phosphatase on an immunoaffinity column yielded two proteins, Mr 59,000 and 43,000, that were catalytically active and calmodulin independent. In a separate experiment, the two subunits of the phosphatase were separated by gel filtration in 6 M urea. Subunit A isolated from the filtration column showed little or no activity in the presence of Ca2+ and calmodulin, but it showed calmodulin-dependent phosphatase activity in the presence of 0.8 mM Mn2+. Subunit B was catalytically inactive. Collectively, these results indicate that subunit A and its proteolytic fragment contain the catalytic site and the antigenic determinant for the monoclonal antibody.

Animals↗