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Biomedical subjects

R H Browne

Publications and source records attributed to R H Browne.

At least 19 recordsLinked to original sources
PubMed2006

Mutations responsible for Larsen syndrome cluster in the FLNB protein.

BACKGROUND: A gene for Larsen syndrome was recently described, and mutations were reported in five cases. OBJECTIVE: To test whether mutations in this gene, FLNB, could explain the disease in our independent collection of sporadic and dominant Larsen syndrome cases; and to test whether mutations occurred in a non-random pattern. RESULTS: Missense mutations were found in each of five cases. Four of the five were new; one was reported in a sporadic case in the original Larsen syndrome study of five cases. All mutations from the two studies were compiled. Clustered mutations were observed within three filamin B protein domains: the calponin homology 2 domain, repeat 14, and repeat 15. This suggested that as few as five (of the total of 46) coding exons of FLNB could be screened to detect Larsen syndrome mutations. Four of these exons were screened in a sixth (sporadic) case and a previously reported G1691S substitution mutation detected. CONCLUSIONS: Mutations in FLNB may be responsible for all cases of Larsen syndrome. They appear to occur in specific functional domains of the filamin B protein. This should simplify diagnostic screening of the FLNB gene. Analyses in larger patient series are warranted to quantify this. The study confirmed the extreme variability in clinical presentation and the presence of unaffected carriers. A molecular screen would be valuable for diagnosis and genetic counselling.

Abnormalities, Multiple↗
PubMed2001

Adolescents undergoing surgery for idiopathic scoliosis: how physical and psychological characteristics relate to patient satisfaction with the cosmetic result.

STUDY DESIGN: Patient satisfaction with the cosmetic result of spinal fusion surgery was studied in 42 cases of adolescent idiopathic scoliosis. Neutral or dissatisfied patients were compared with satisfied patients on several physical and psychological characteristics. OBJECTIVES: To determine whether adolescents generally report satisfaction with the postoperative appearance of their back after the correction of severe curves and whether preoperative medical and/or psychological factors distinguish between patients who will report satisfaction with the cosmetic surgical result from those who will report neutrality or dissatisfaction. SUMMARY OF BACKGROUND DATA: Previous reports emphasize the need for medical outcomes research that evaluates both patient satisfaction and technical success. Patient satisfaction with spinal surgery has largely been evaluated in retrospective studies and most consistently related to postoperative cosmesis and degree of curve correction. METHODS: Forty-two adolescents with idiopathic scoliosis without comorbidity, who were 12 years 6 months of age or older, and who did not require both anterior and posterior spinal fusion, were studied preoperatively and postoperatively by physical and psychological measurements. RESULTS: Of patients undergoing surgical correction of severe curves, 73% reported satisfaction with the cosmetic result. Neutral or dissatisfied patients were more likely than satisfied patients to have a lower body mass index (P < 0.05), to be younger in menarcheal status (P < 0.05), and have a King II or King III curve type. Preoperative psychological difficulties (P < 0.05) and unmet expectations regarding the postoperative cosmesis (P < 0.05) were more common among neutral or dissatisfied patients. CONCLUSIONS: Most adolescents with idiopathic scoliosis expressed satisfaction with the cosmetic surgical result. Preoperative physical characteristics, psychological difficulties, and unrealistic expectations regarding postoperative cosmesis are associated with patient neutrality or dissatisfaction.

Adolescent↗
PubMed2001

The Littler line method and the area under a Gaussian curve: a new method of assessing digital range of motion.

A new method of measuring digital range of motion (the Littler line method) is presented. When a Gaussian curve is centered over the Littler line and the appropriate area under the curve is computed, this area can provide a measure of the functional range of motion regained by an injured digit. Seventeen children (24 digits) with flexor tendon injuries were evaluated at an average follow-up period of 58 months (range, 12-121 months). The Littler line/Gaussian curve method was found to be more reproducible than total active motion, particularly in zone I and II injuries. This method can serve as a more meaningful functional assessment tool than a linear measurement such as total active motion, because it emphasizes digital motion in the mid-ranges of digital motion. (J Hand Surg 2001;26A:23-30.

Adolescent↗
PubMed2000

Prospective analysis of strength in spinal muscular atrophy. DCN/Spinal Muscular Atrophy Group.

Spinal muscular atrophy is a genetic disorder of the motor neurons that causes profound hypotonia, severe weakness, and often fatal restrictive lung disease. Patients with spinal muscular atrophy present a spectrum of disease from the most severe infantile-onset type, called Werdnig-Hoffmann disease (type 1), associated with a mortality rate of up to 90%, to a late-onset mild form (type 3), wherein patients remain independently ambulatory throughout adult life. Although many clinicians agree that patients with spinal muscular atrophy lose motor abilities with age, it is unknown whether progressive weakness occurs in all patients with spinal muscular atrophy. We present here results of the first prospective study of muscle strength in patients with spinal muscular atrophy. There was no loss in muscle strength as determined by a quantitative muscle test during the observation period. However, motor function diminished dramatically in some patients with spinal muscular atrophy. Explanations for this loss of function could not be determined from our data. Decrease in motor function could be caused by factors other than loss of strength. Therefore, it is not clear from our results whether spinal muscular atrophy is a neurodegenerative disease. We conclude that treatment trials in spinal muscular atrophy should be designed with consideration of the natural history of strength and motor function in this disorder.

Adolescent↗
PubMed1997

A comparison between the Boston brace and the Charleston bending brace in adolescent idiopathic scoliosis.

STUDY DESIGN: The authors studied 319 patients with adolescent idiopathic scoliosis treated at the same institution with either a Boston brace or a Charleston bending brace. OBJECTIVES: To determine if both orthoses are equally effective in stopping curve progression and preventing the need for surgical correction. SUMMARY OF BACKGROUND DATA: Early reports suggest that the Charleston brace may be comparable to the Boston brace in its effectiveness and that both braces positively influence the natural history of idiopathic scoliosis. METHODS: Skeletally immature (Risser 0, 1, or 2) patients with idiopathic scoliosis who were 10 years old or older at the time of brace prescription, had curves from 25 degrees to 45 degrees, and had no prior treatment were studied retrospectively. All measurements were collected by a single observer, and all patients were followed up to skeletal maturity. RESULTS: The Boston brace is more effective than the Charleston brace, both in preventing curve progression and in avoiding the need for surgery. These findings were most notable for patients with curves of 36 degrees-45 degrees, in whom 83% of the those treated with a Charleston brace had curve progression of more than 5 degrees, compared with 43% of those treated with the Boston brace (p < 0.0001). CONCLUSION: When given the choice between these two orthoses in the treatment of adolescent idiopathic scoliosis, the authors recommend use of the Boston brace. The Charleston brace should be considered only in the treatment of smaller single thoracolumbar or single lumbar curves.

Adolescent↗
PubMed1997

The prevalence of back pain in children who have idiopathic scoliosis.

A retrospective study of 2442 patients who had idiopathic scoliosis was performed to determine the prevalence of back pain and its association with an underlying pathological condition. Five hundred and sixty (23 per cent) of the 2442 patients had back pain at the time of presentation, and an additional 210 (9 per cent) had back pain during the period of observation. There was a significant association between back pain and an age of more than fifteen years, skeletal maturity (a Risser sign of 2 or more), postmenarchal status, and a history of injury. There was no association with gender, family history of scoliosis, limb-length discrepancy, magnitude or type of curve, or spinal alignment. At the latest follow-up evaluation, 324 (58 per cent) of the 560 patients who had had back pain at presentation had no additional symptoms. Forty-eight (9 per cent) of the 560 patients who had back pain had an underlying pathological condition: twenty-nine patients had spondylolysis or spondylolisthesis, nine had Scheurmann kyphosis, five had a syrinx, two had a herniated disc, one had hydromyelia, one had a tethered cord, and one had an intraspinal tumor. A painful left thoracic curve or an abnormal neurological finding was most predictive of an underlying pathological condition, although only eight of the thirty-three patients who had such findings were found to have such a condition. When a patient with scoliosis has back pain, a careful history should be recorded, a thorough physical examination should be performed, and good-quality plain radiographs should be made. If this initial evaluation reveals normal findings, a diagnosis of idiopathic scoliosis can be made, the scoliosis can be treated appropriately, and non-operative treatment can be initiated for the back pain. It is not necessary to perform extensive diagnostic studies to evaluate every patient who has scoliosis and back pain.

Adolescent↗
PubMed1996

Reproducibility in the measurement of atlanto-occipital instability in children with Down syndrome.

STUDY DESIGN: This study compared the reproducibility of three techniques used to measure translation between the occiput and C1 in children with Down syndrome. OBJECTIVES: Intraobserver and interobserver variability were computed to determine if there is a reliable way to measure occiput-C1 instability. SUMMARY OF BACKGROUND DATA: No studies have been performed comparing measurement techniques in children with Dow syndrome. METHODS: Powers ratios, basion-axial intervals, and translational anteroposterior motion as described by Wiesel and Rothman were calculated for 50 pairs of flexion-extension lateral cervical radiographs from children with Down syndrome. Calculations were made on two occasions by four reviewers. RESULTS: Mean differences between measurements for two observers were 0.14 for the Powers ratio, 1.3 mm for the Wiesel technique, and 1.8 mm for the basion-axial interval. The 95th percentiles of the differences between measurements for two observers were 0.38 for Powers ratios, 3.5 mm for the Wiesel technique, and 5.3 mm for the basion-axial interval. CONCLUSIONS: Measurement of atlanto-occipital translation by any of these methods is not reproducible. Although the technique by Wiesel and Rothman is the easiest to apply, confirmation of instability with magnetic resonance imaging should guide management.

Adolescent↗
PubMed1996

Intraosseous infusion of prostaglandin E2 prevents disuse-induced bone loss in the tibia.

We investigated whether intraosseous injection of prostaglandin E2 would preserve tibial bone mass in the skeletally unloaded limb of a large animal model. Skeletal unloading of one rear limb was produced by unilateral Achilles tenectomy in the goat. Prostaglandin E2 was injected at 0.5 or 1.0 mg (1 ml of volume) twice daily, beginning on day 7 and continuing for 10 days, through an implant that had been surgically placed in the proximal tibial metaphysis. Thirty-five days after surgery, the tibiae were harvested for measurement of static and dynamic bone parameters and mechanical characteristics using transmission ultrasound. Prostaglandin E2 produced a dose-dependent increase in the formation of woven new bone at all bone envelopes. The 1.0 mg dosage prevented and partially reversed the effects of skeletal unloading and added new bone (p < 0.05) compared with the unloaded tibiae. Because prostaglandin E2 increased both bone formation and resorption and the new bone produced was primarily woven bone, the material properties of the tibiae infused with prostaglandin E2 did not increase significantly during the study compared with the unloaded and weight-bearing tibiae.

Animals↗
PubMed1995

On the use of a pilot sample for sample size determination.

To compute the sample size needed to achieve the planned power for a t-test, one needs an estimate of the population standard deviation sigma. If one uses the sample standard deviation from a small pilot study as an estimate of sigma, it is quite likely that the actual power for the planned study will be less than the planned power. Monte Carlo simulations indicate that using a 100(1-gamma) per cent upper one-sided confidence limit on sigma will provide a sample size sufficient to achieve the planned power in at least 100(1-gamma) per cent of such trials.

Clinical Trials as Topic↗
PubMed1995

Interactions of valproic acid with carbamazepine and its metabolites' concentrations, concentrations ratios, and level/dose ratios in epileptic children.

In two groups of epileptic children receiving carbamazepine (CBZ) therapy with or without valproic acid (VPA) comedication, we investigate the drug interactions of VPA on serum CBZ and its metabolites' concentrations, concentration ratios, and level/dose ratios. Serum total and free CBZ-10, 11-epoxide (CBZ-E) concentrations are significantly increased in patients taking CBZ plus VPA, together with higher CBZ-E/CBZ concentration ratios and CBZ-E level/dose ratios. These results reflect the accumulation of CBZ-E. The decreased concentration ratios of trans-10, 11-dihydroxy-10, 11-dihydro-CBZ (CBZ-H)/CBZ-E observed in patients taking CBZ plus VPA suggest an inhibition in the biotransformation from CBZ-E to CBZ-H. Significant negative correlations are found between serum VPA level and CBZ-H/CBZ-E concentration ratios, indicating that the inhibition of CBZ-E hydrolysis by VPA may depend on the concentration of VPA (total or free CBZ-H/CBZ-E concentration ratio = [formula: see text], respectively). VPA concentration also shows significant positive correlations with CBZ-E and CBZ level/dose ratios. Patients taking CBZ plus VPA have significant higher free fractions of CBZ and CBZ-E than do patients on CBZ alone, suggesting a protein-binding displacement by VPA.

Carbamazepine↗
PubMed1995

Posterior arthrodesis and instrumentation in the immature (Risser-grade-0) spine in idiopathic scoliosis.

We performed a retrospective study of the long-term results of posterior instrumentation and arthrodesis of the spine in forty-three patients who had idiopathic scoliosis and a Risser grade of 0 at the time of the operation. The average age of the patients was 12.4 years (range, 6.7 to 15.5 years) at the time of the operation. The triradiate cartilages were open in twenty-three patients and closed in twenty. At the time of the latest follow-up evaluation (average duration of follow-up, four years; range, two to eleven years), seventeen patients had a Risser grade of 5; twenty-two, 4; two, 3; one, 2; and one, 0. The crankshaft phenomenon, a progressive deformity resulting from continued growth of the anterior aspect of the spine after posterior arthrodesis, was seen in only one patient who had closed triradiate cartilages and in ten patients who had open triradiate cartilages (p = 0.004). The most common radiographic finding was a progressive rib-vertebra angle difference, which increased more than 10 degrees in seven of the eleven patients who had the crankshaft phenomenon. The mean increase in these eleven patients was 22 degrees, compared with no increase in the thirty-two other patients (p < 0.0001). Open triradiate cartilages (r = 0.58, p = 0.0001) and a younger age at the time of the operation (p < 0.0001) were predictive of the amount of progression as a result of the crankshaft phenomenon. In patients who had open triradiate cartilages, less skeletal maturity was also predictive of progression as a result of the crankshaft phenomenon (r = -0.72, p = 0.0002).

Adolescent↗
PubMed1994

Effects of end-tidal gas monitoring and flow rates on hemodynamic stability and recovery profiles.

This study was designed to evaluate the impact of routine end-tidal anesthetic gas monitoring on the intraoperative hemodynamic stability and early recovery profile in 253 consenting ASA physical status I-III patients undergoing elective otolaryngologic procedures with isoflurane or enflurane anesthesia. Patients were randomly assigned to one of six treatment groups: Group I, monitored high-flow isoflurane; Group II, unmonitored high-flow isoflurane; Group III, monitored low-flow isoflurane; Group IV, unmonitored low-flow isoflurane; Group V, monitored low-flow enflurane; or Group VI, unmonitored low-flow enflurane. After a standardized induction sequence, anesthesia was maintained by administering variable concentrations of isoflurane or enflurane in an air/oxygen mixture at two different total gas flow rates (0.7 L/min or 3.5 L/min, respectively). Mean arterial pressure (MAP), heart rate (HR), and end-tidal (ET) anesthetic concentrations were recorded by a computer throughout the operation. The resident anesthesiologist was instructed to maintain an adequate "depth of anesthesia" by varying the administration of isoflurane (Groups I-IV) or enflurane (Groups V and VI) with or without end-tidal gas monitoring. Intraoperative hemodynamic stability was assessed in each patient and reported as the average error from the preincisional (baseline) MAP, average absolute error from the baseline MAP, coefficients of variation for HR, systolic, diastolic, and MAP values, and ET anesthetic concentrations. Recovery times from discontinuation of the volatile drug until awakening, following commands, and postanesthesia care unit (PACU) discharge were recorded. The six study groups had similar intraoperative MAP and HR values, coefficients of variation, and numbers of episodes of hypertension, hypotension, tachycardia, and bradycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

The effect of phosphate supplementation on linear growth in children with X-linked hypophosphatemia.

BACKGROUND: X-linked hypophosphatemia is the most common inherited cause of rickets. Current therapy for this disorder includes vitamin D and phosphate supplementation; however, phosphate therapy has been associated with nephrocalcinosis. The purpose of this study is to evaluate the effect of oral phosphate therapy on growth in patients with X-linked hypophosphatemia treated with either calcitriol or dihydrotachysterol (vitamin D). METHODS: We retrospectively evaluated the prepubertal growth of 36 children with X-linked hypophosphatemia. The height standard deviation score (Z-score) of patients initially treated with vitamin D alone and the Z-scores of patients treated with vitamin D and phosphate therapy were compared. In addition, the growth of therapy were compared. In addition, the growth of patients treated with vitamin D was compared with that of patients treated with vitamin D and phosphate from the outset of therapy. RESULTS: Patients treated with vitamin D alone for 5.36 +/- 2.18 years had an improvement in Z-score from -3.1 +/- 1.10 to -2.49 +/- 0.66 SDS, P < .05. Adding phosphate therapy for patients initially treated with vitamin D alone for 4.83 +/- 2.99 years did not further improve Z-score (-2.49 +/- 0.66 vs -2.35 +/- 0.83). Initial therapy with vitamin D and phosphate for 4.33 +/- 2.19 years also improved Z-score, (-2.84 +/- 1.02 vs -1.98 +/- 0.82, P < .05). The change in Z-score was similar to the group treated with vitamin D alone compared with the group treated initially with vitamin D and phosphate (0.65 +/- 0.54 vs 0.85 +/- 0.65, respectively). CONCLUSION: These data demonstrate that both vitamin D alone and in combination with phosphate improved linear growth. Adding oral phosphate for children initially treated with vitamin D alone did not improve Z-score. Initial therapy with vitamin D and vitamin D plus phosphate produced similar changes in linear growth.

Administration, Oral↗
PubMed1993

Progression of the curve in boys who have idiopathic scoliosis.

The prevalence of curve progression was evaluated in 210 boys who had idiopathic scoliosis. A minimum age of eight years, a deformity of at least 10 degrees, and radiographic follow-up of one year or progression of the curve within the first year of follow-up were the criteria for inclusion in the study. Of the 210 patients, sixty-eight (32 per cent) had progression of 10 degrees or more. Four of the five patients who had had an initial curve of 50 degrees or more subsequently had a spinal arthrodesis. The risk of progression was significantly greater for patients who were at an earlier Risser stage (p < 0.002) and for those who were younger (p < 0.005). The risk of progression was also greater for patients who had had a larger curve at the time of presentation; of the sixty-three boys for whom the Risser grade was 1, 2, 3, 4, or 5 when they were first seen and who had a curve of 25 degrees or more, twenty (32 per cent) had progression, compared with only two (5 per cent) of the thirty-eight who had a Risser grade of 1, 2, 3, 4, or 5 and a curve of 24 degrees or less. Of the thirty-four patients for whom the Risser grade was 4 when they were first seen, five (15 per cent) had progression.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Measurement of scoliosis and kyphosis radiographs. Intraobserver and interobserver variation.

Interobserver variations for measurements of the Cobb angle on radiographs of patients who had kyphosis were comparable with those on the radiographs of patients who had scoliosis. Four staff orthopaedists and one physical therapist measured eight radiographs that showed scoliosis and twenty that showed kyphosis. The measurements were made on two occasions and in random order. For scoliosis, the average difference between readings was 3.8 degrees, and 95 per cent of the differences were 8 degrees or less (range, 0 to 10 degrees). These findings were in keeping with those of other published reports. For kyphosis, the average difference between readings was 3.3 degrees, and 95 per cent of the differences were 7 degrees or less (range, 0 to 30 degrees). One investigator rated the kyphosis radiographs with respect to clarity. There was a trend to less variation with clearer radiographs, but this was not significant. The end-vertebrae were pre-selected for some radiographs and were freely chosen by the interpreter for others. Reliability was not significantly improved when the end-vertebrae of the curve had been pre-selected. Using the statistical method called tolerance limits, we determined that if one were to be 95 per cent confident that a measured difference represented a true change, the difference would have to be 10 degrees for scoliosis radiographs and 11 degrees for kyphosis radiographs. The probability that a measured difference is due to measurement error alone (that is, a false-positive reading) was calculated.

Analysis of Variance↗