Search PubMed⌕ Search

Biomedical subjects

L N Brown

Publications and source records attributed to L N Brown.

At least 19 recordsLinked to original sources
PubMed2006

Identifying reliable change in tactile temporal thresholds in multiple sclerosis: test-retest reliability.

BACKGROUND: Tactile temporal thresholds are typically significantly higher (ie, prolonged) in multiple sclerosis (MS) patients when compared to controls and increase significantly during relapses, probably reflecting integrity of conduction across a portion of the corpus callosum. As part of an ongoing validation study of tactile temporal thresholds, the test-retest reliability of these thresholds was examined in patients with MS. METHODS: Tactile temporal thresholds were measured in 61 MS patients during two separate test sessions within three weeks. Test-retest reliability and the standard error of measurement were calculated. The threshold of change in tactile temporal thresholds in MS patients that would correspond to real change beyond measurement error with 95% certainty was also calculated. RESULTS: The test-retest reliability of this measure of tactile temporal thresholds was 0.93. The threshold indicating change beyond chance or measurement error with 95% certainty was 19 ms. CONCLUSIONS: This measure of tactile temporal thresholds has excellent test-retest reliability and a change of greater than 19 ms is highly likely to represent real change. This measure is promising as a precise, reliable outcome measure in MS.

Adult↗
PubMed2005

Tactile temporal thresholds detect relapse-related changes in multiple sclerosis: a preliminary study.

BACKGROUND: Tactile temporal thresholds, which represent the time separating the onset of two tactile stimuli when they are judged as simultaneous, can differentiate a group of people with multiple sclerosis (MS) from normal controls. Demyelination, axonal injury and loss, and altered information processing all occur in MS and may cause these increased thresholds. Thus, tactile temporal thresholds may be a useful outcome measure in MS. Our objective was to assess whether tactile temporal thresholds reflect change during a MS relapse. METHODS: During a study to evaluate the stability of tactile temporal thresholds in people with MS, two participants suffered relapses. Both events were associated with prolonged thresholds (i.e., significantly increased thresholds). CONCLUSIONS: Tactile temporal thresholds can detect neurologic worsening and thus warrant further evaluation as a useful method to facilitate in the monitoring of disease change in people with MS.

Adult↗
PubMed2000

Hemispheric equivalence and age-related differences in judgments of simultaneity to somatosensory stimuli.

Hemispheric asymmetries, interhemispheric transfer time (IHTT), and age-related differences in judgments of simultaneity to tactile stimulation were examined. Two mechanical stimulators were employed to: (1) Determine whether both cerebral hemispheres are equally capable of processing fine tactile temporal information; (2) determine whether there is an age-related differential hemispheric decline in judgments of simultaneity, and (3) determine if simultaneity thresholds for tactile stimuli increase with advanced age. Tactile simultaneity thresholds were measured by using a modified parameter estimation by sequential testing algorithm. Participants judged whether pairs of tactile stimulation to index and middle fingers were delivered simultaneously. Results of both bimanual and unimanual conditions supported a model of hemispheric equivalence in that both hemispheres were equally capable of making judgments of simultaneity to fine tactile stimuli. The results further suggested that the hemispheric equivalence for judgments of simultaneity remains stable across adulthood. However, IHTTs of older adults were more than double that of younger adults, indicating a significant decrease in the speed of neural conduction. As well, relative to younger adults, older adults had significantly higher simultaneity thresholds.

Adult↗
PubMed1991

Critical thinking: impact on nursing education.

Critical thinking is considered an essential component of nursing science. As a concept in nursing education, however, critical thinking is not clearly understood nor systematically applied. A survey of deans and directors of baccalaureate and higher-degree schools of nursing accredited by the National League for Nursing examined perceptions of critical thinking as it is currently characterized in nursing education. Results indicated that critical thinking was conceptualized as a variant of the scientific method. It was explicated as a rational-linear problem-solving activity which reflected the nursing process. The findings demonstrated the respondents' lack of clarity about the fullest expression of the mechanisms and operations of critical thinking process and applications.

Education, Nursing, Baccalaureate↗
PubMed1988

Comparison of Melengestrol Acetate-Prostaglandin F(2)alpha to Syncro-Mate B for estrus synchronization in beef heifers.

Three hundred and ten yearling heifers of various breeds were used in five trials to compare two estrus synchronization treatments. Treatment 1 consisted of Melengestrol Acetate-Prostaglandin F(2)alpha (MGA-PGF(2)alpha). Heifers were fed 0.5 mg MGA/head/d for 14 to 16 d. Sixteen or 17 d after the final MGA feeding, heifers were injected i.m. with 25 mg PGF(2)alpha. Treatment 2 consisted of Syncro-Mate B (SMB). Heifers were given a 9-d norgestomet implant plus an injection containing 3 mg norgestomet and 5 mg estradiol valerate i.m. at implant insertion. Heifers were observed for estrus at 6-h intervals for 120 h after the end of treatments and were artificially inseminated 12 to 18 h after observed estrus. Heifers synchronized with MGA-PGF(2)alpha and SMB had a similar (P > 0.10) estrous response (83.4 vs 90.2%) and a similar (P > 0.10) degree of synchrony (71.8 vs 79.0%) following treatment. However, the synchronized conception rate (68.7 vs 40.6%) and the synchronized pregnancy rate (57.3 vs 36.6%) were higher (P < 0.01) in MGA-PGF(2)alpha than SMB heifers. Breeding season pregnancy rates were similar in both treatment groups. Heifers in both groups that were classified as cycling prior to initiation of treatment had improved reproductive performance following synchronization compared with those classified as noncycling. Based on higher synchronized conception and pregnancy rates and lower labor requirements and drug costs, the MGA-PGF(2)alpha system appears to be a better method to synchronize estrus in beef heifers than the SMB system.

Journal Article↗
PubMed1986

Synchronization of estrus in embryo transfer recipients receiving demi-embryos with Syncro-Mate B or estrumate.

One hundred thirty-five crossbred heifers were used to compare the effectiveness of Estrumate and Syncro-Mate B in synchronizing estrus in recipient heifers for transfer of demi-embryos. A higher percentage (P<0.01) of Syncro-Mate B heifers showed estrus within 5 d following treatment than did Estrumate heifers (100.0 vs 85.1%). Demi-embryos were transferred to 41 and 26 heifers treated with Syncro-Mate B and Estrumate, respectively. The pregnancy rate of heifers synchronized with Estrumate was higher (P<0.01) than that of heifers synchronized with Syncro-Mate B (64.3 vs 27.8%). A single blood sample was collected on the day of embryo transfer from all heifers receiving demi-embryos, and progesterone concentration was determined. There were no significant differences in mean serum progesterone concentrations either between heifers synchronized with Syncro-Mate B and Estrumate or between pregnant and open heifers within synchronization treatment. There was no relationship between serum progesterone concentration and pregnancy rate in the Estrumate recipients (P>0.10). However, 25.0% of the Syncro-Mate B recipients had serum progesterone levels <1.00 ng/ml, and these heifers had a lower pregnancy rate (P<0.05) than Syncro-Mate B heifers with serum progesterone levels between 1.00 to 3.00 ng/ml. It appears that the Syncro-Mate B heifers with <1.00 ng/ml progesterone had either a delay in corpora lutea function or a continuously reduced concentration of serum progesterone which altered the uterine environment of these heifers and caused the lower pregnancy rate in the Syncro-Mate B group. Based on the large difference in pregnancy rates, Estrumate appears to be a more effective method to synchronize estrus in recipient heifers receiving demi-embryos.

Journal Article↗
PubMed1976

Experimentally induced foot rot in feedlot cattle fed rations containing organic iodine (ethylenediamine dihydriodide) and urea.

Foot rot was experimentally induced in feedlot cattle with a mixed inoculum of Fusobacterium necrophorum (Sphaerophorus necrophus) and Bacteroides melaninogenicus. Both bacteria were isolated from the lesions. Isolates of F necrophorum from 2 of the lesions were serologically compared, using a passive hemagglutination test with the strain used to induce the lesions. These isolates were serologically similar but not identical, indicating antigenic change had occurred during animal passage. The addition of ethylenediamine dihydriodide or urea to the rations did not affect the frequency of experimentally induced foot rot.

Animal Feed↗
PubMed1975

Clinical infectious bovine rhinotracheitis in cattle fed organic iodine and urea.

The feeding of ethylenediamine dihydriodide (EDDI) at the dose levels of 50 and 500 mg/animal/day and urea at the dose level of 45 g/animal/day did not affect duration of clinical signs, body weight gain, magnitude or duration of fever, serum concentration of glutamic oxalacetic transaminase, packed cell volume, and differential white blood cell counts in feeder cattle experimentally infected with infectious bovine rhinotracheitis (IBR) virus. However, coughing and abundance of nasal discharge were significantly greater in calves fed EDDI before and during primary IBR virus infection. Those calves fed 500 mg of EDDI/day coughed more, had greater nasal discharge, and exhibited greater lacrimation than did those given the smaller dose. These 3 clinical signs were considered to reflect both the expectorant action of EDDI and the pathogenic effects of IBR virus. In all calves, including controls, the coughing, nasal discharge, and lacrimation were most prominent during the period of peak infection (7 to 14 days after the calves were given intranasal inoculation) of the IBR virus. Total serum iodine concentration became maximal (mean of 1,400 ng/ml) in 8 calves after they had been fed the larger dose of EDDI for 2 weeks. This value was maximal (about 300 ng/ml) in another 8 calves after 3 weeks' feeding of the smaller dose (50 mg/day). When EDDI exposure was maintained at the dose level of 50 mg/day for 5 weeks longer, mean serum iodine values remained at about 275 ng/ml, and those of control calves averaged 140 ng/ml.

Ammonia↗