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R Brand

Publications and source records attributed to R Brand.

At least 55 records · Page 3Linked to original sources
PubMed2000

Functional residual capacity and static compliance during the first year in preterm infants treated with surfactant.

Individual lung development during the first year of life was studied in surfactant treated preterm infants with respiratory distress syndrome (RDS) and healthy controls, as well as in a group who subsequently developed chronic lung disease of the newborn (CLDN). Lung development was assessed from functional residual capacity (FRC) and compliance of the respiratory system (Crs). Twenty-one infants with RDS after preterm birth received surfactant treatment. Six of them developed CLDN. Eighteen preterm infants without RDS served as a control group. Lung function measurements were performed at term age and 4, 8, and 12 months afterwards. FRC was obtained by means of the closed-system helium dilution technique whereas static Crs was obtained by means of the weighted spirometer technique. At term age, FRC was lower in the CLDN group compared with uncomplicated RDS and controls (p < 0.05). No significant differences between groups were found in the development of FRC during the first year of life (p = 0.4). No differences were found in Crs during the first year of life in surfactant treated infants who recovered from uncomplicated RDS and the control group. However, lower values were found in the CLDN group (p < 0.05). We conclude that surfactant treated infants without CLDN have similar lung development during the first year of life as control preterm infants.

Functional Residual Capacity↗
PubMed2000

Etiology of nephrocalcinosis in preterm neonates: association of nutritional intake and urinary parameters.

BACKGROUND: Nephrocalcinosis (NC) in preterm neonates has been described frequently, and small-scale studies suggest an unfavorable effect on renal function. The etiologic factors have not yet been fully clarified. We performed a prospective observational study to identify factors that influence the development of NC. METHODS: The study population consisted of 215 preterm neonates with a gestational age <32 weeks. Clinical characteristics and intake in the first four weeks of calcium, phosphorus, vitamin D, protein, and ascorbic acid were noted. Serum calcium, phosphate, vitamin D, magnesium, uric acid, creatinine, urea and urinary calcium, phosphate, oxalate, citrate, magnesium, uric acid, and creatinine were assessed at four weeks of age and at term. Renal ultrasonography (US) was performed at four weeks and at term. At term was defined as a postconceptional age of 38 to 42 weeks. RESULTS: NC was diagnosed by means of US in 33% at four weeks and in 41% at term. Patients with NC at four weeks had a significantly higher mean intake of calcium (P < 0.05), phosphorus (P < 0.05), and ascorbic acid (P < 0.01) than patients without NC. They had a higher mean serum calcium (2.55 vs. 2.46 mmol/L, P < 0.01) and a higher mean urinary calcium/creatinine ratio (2.6 vs. 2.1 mmol/mmol, P < 0.05). Patients with NC at term had a lower birth weight (1142 vs. 1260 g, P < 0.05) and a lower gestational age (28.8 vs. 29.4 weeks, P < 0.05), were treated significantly longer with furosemide, dexamethasone, theophylline, and thiazides, developed chronic lung disease more frequently (40 vs. 16%, P < 0.001), and had a higher mean urinary calcium/creatinine ratio (2.7 vs. 2.3 mmol/mmol, P < 0.05) and a lower mean urinary citrate/calcium ratio (1.1 vs. 1.7 mmol/mmol, P = 0.005). CONCLUSIONS: NC develops as a result of an imbalance between stone-inhibiting and stone-promoting factors. A high intake of calcium, phosphorus, and ascorbic acid, a low urinary citrate/calcium ratio, a high urinary calcium/creatinine ratio, immaturity, and medication to prevent or treat chronic lung disease with hypercalciuric side effects appear to contribute to the high incidence of NC in preterm neonates.

Ascorbic Acid↗
PubMed2000

The time and financial impact of training fellows in endoscopy. CORI Research Project. Clinical Outcomes Research Initiative.

OBJECTIVE: To use a national endoscopy database (Clinical Outcomes Research Initiative, CORI) to determine 1) if fellow involvement increases procedure time; and 2) the financial impact of fellow participation for academic centers compared to private practice. METHODS: CORI database from 4/1/97 to 4/1/99 was used to compare endoscopists from private practices, academic medical centers, and Veterans Administration hospitals, with or without fellows-in-training. Data were captured in a computer-generated endoscopy report and transmitted to a central database for analysis. Duration of procedure (minutes) was recorded for diagnostic esophagogastroduodenoscopy (EGD), EGD with biopsy, diagnostic colonoscopy, and colonoscopy with biopsy, in ASA 1 patients. Financial outcomes used 1999 Medicare reimbursement rates for respective procedures and were calculated as procedures per hour on a theoretical practice of 4000 procedures. RESULTS: Teaching fellows endoscopy added 2-5 min for EGD, with or without biopsy, and 3-16 min for colonoscopy, with or without biopsy. Calculating the number of procedures/h of endoscopy, the reimbursement loss resulting from using fellows-in-training in a university setting would be half a procedure/h. In Veterans Administration hospitals, training of fellows would lose a full procedure/h. In a model of 1000 procedures each of EGD, EGD with biopsy, colonoscopy, and colonoscopy with biopsy, the reimbursement difference between private practice physicians or academic attending physicians and procedures involving fellows-in-training would be $500,000 to $1,000,000/yr. CONCLUSIONS: Fellow involvement prolonged procedure time by 10-37%. Thus, per-hour reimbursement is reduced at teaching institutions, causing financial strain related to these time commitments.

Academic Medical Centers↗
PubMed2000

Viscoelastic dissipation in compact bone: implications for stress-induced fluid flow in bone.

Viscoelastic properties of wet and dry human compact bone were studied in torsion and in bending for both the longitudinal and transverse directions at frequencies from 5 mHz to 5 kHz in bending to more than 50 kHz in torsion. Two series of tests were done for different longitudinal and transverse specimens from a human tibia. Wet bone exhibited a larger viscoelastic damping tan delta (phase between stress and strain sinusoids) than dry bone over a broad range of frequency. All the results had in common a relative minimum in tan delta over a frequency range, 1 to 100 Hz, which is predominantly contained in normal activities. This behavior is inconsistent with an optimal "design" for bone as a shock absorber. There was no definitive damping peak in the range of frequencies explored, which could be attributed to fluid flow in the porosity of bone.

Aged↗
PubMed2000

Ultrasonographic features of nephrocalcinosis in preterm neonates.

Nephrocalcinosis (NC) in preterm neonates has been reported frequently and small studies suggest an unfavourable effect on renal function. Data on ultrasonic features are limited and the reproducibility of ultrasonography (US) in detecting NC in preterm neonates is unknown. In this study, interobserver and intraobserver agreement of US was determined through videotape recordings of US examinations of preterm neonates. Furthermore, a prospective US study was performed in 215 preterm neonates (gestational age < 32 weeks) to evaluate ultrasonic characteristics, incidence, time course and effect on kidney length of NC. Patients were studied at 4 weeks after birth and at term. Patients with NC were followed for 2 years. NC was defined as bright reflections in the medulla or cortex seen in both transverse and longitudinal direction. The length of the kidneys was noted. The kappa value was 0.84 for intraobserver and 0.46 for interobserver agreement, whereas the overall agreement was 73%. NC was found in 50 of 150 (33%) patients at 4 weeks and in 83 of 201 patients (41%) at term. NC was localized mainly in the medulla. At 1 and 2 years, NC had persisted in 36% and 26%, respectively, of the patients with NC at term. Kidney length was comparable with normal values. In conclusion, US has a very good intraobserver agreement but a moderate interobserver agreement in detecting NC. Medullary NC is common among preterm neonates. During the first 2 years of life, the incidence decreases spontaneously and NC does not influence kidney length.

Follow-Up Studies↗
PubMed2000

Length velocity acceleration at 9 months of age in a representative birth cohort of Dutch infants.

According to the ICP (infancy-childhood-puberty) growth model, statural growth can be divided into three partially superimposed components assumed to represent different physiologic mechanisms. This model predicts a sudden acceleration of length velocity (LV) at the onset of the childhood component around 9 months. The existence of such an infancy-childhood growth spurt has not yet been firmly corroborated by epidemiological studies. In the present study length measurements were made at the target ages of 1, 3, 6, 9, 12, 15, 18 and 24 months in a birth cohort of 2034 infants. In order to check whether length growth showed a continuous smooth pattern, different mathematical models were fitted to the individual growth curves. The models included Count and Guo functions, 5th order polynomial and combinations of 5th order polynomial with the logarithmic term of the Count function and the square root term of the Guo function. We showed that in boys and girls there is a small but systematic lack of fit of the mathematical modeling, due to a sudden acceleration of LV around 9 months. In addition there was an increase in variation of attained length at this age. Comparison of unbalanced ANOVA models with and without addition of dummy variables for the target ages confirmed that there was an acceleration around 9 months that, if corrected for, leads to a significantly improved model fit (likelihood ratio test p < 0.0001). In absolute terms of LV, the misfit at 9 months was not greater than 0.5 cm/year on average. We conclude that the results of this study support the existence of a late infancy growth spurt. In our opinion, however, the magnitude of the phenomenon does not legitimate construction and use of discontinuous growth references such as the ICP reference.

Aging↗
PubMed2000

Weight bearing area during gait in normal and dysplastic hips.

The size and the shape of the weight bearing area in adult human hips depend on the forces acting in the hip and therefore change during the body motion. In this work the size and the shape of the weight bearing area in several phases of gait are estimated. The forces acting in the hip were determined through laboratory measurements and analyzed by mathematical models. The dysplastic hips are distinguished from the normal ones by a smaller center-edge angle of Wiberg while the time course of the forces acting in the hip is assumed to be the same in both cases. It is shown how radial articular stress is distributed over the weight bearing area in both cases. In normal human hips the weight bearing area occupies a rather large portion of the acetabulum-femoral head contact area while in dysplastic hips stress distribution is unfavourably concentrated in a smaller weight bearing area.

Adult↗
PubMed2000

Peak contact stress in human hip during gait.

The contact stress in a human hip is not uniform and it changes with different body positions. The changing location of the peak contact stress during gait may indicate the predilection sites for further development of osteoarthritis in the hip. On the basis of laboratory measurements and by using mathematical models of forces and stresses in human hip we determined the points of the peak contact stress in successive phases of gait. Results show that the peak stress points are mostly located in the posterior-medial portion of the weight bearing area, which corresponds well to the clinical observations. It is also shown that in the pathological conditions of hip dysplasia the peak contact stress trajectory is located more laterally and anteriorly.

Gait↗
PubMed1999

Nitric oxide metabolites, cyclic guanosine 3,5 monophosphate and dimethylarginines during and after uncomplicated pregnancies: a longitudinal study.

OBJECTIVE: In cross-sectional studies, the variability between women may mask or deny gestational changes, related to the nitric oxide-cyclic GMP system. Therefore, we analyzed longitudinally as markers of this system, the urinary levels of nitrite+nitrate (NOx), cyclic guanosine 3',5' monophosphate (cGMP) and of the inhibitor of nitric oxide synthase, dimethylarginine (DMA). STUDY DESIGN: Late-afternoon urine samples were obtained from 20 women with uncomplicated pregnancies and nine non-pregnant women. Creatinine concentrations (mol) were determined with the Jaffé reagent and NOx (mmol) with the Griess reagent after reduction of nitrate. cGMP (micromol) was determined in an enzyme immunoassay and DMA (mmol) after solid-phase extraction and liquid chromatography. Trend analyses and (paired) t-tests were done for detection of time-related differences. RESULTS: The NOx/creatinine (mmol/mol) ratios of the non pregnant women (63.8+/-18.8, S.D.) did not differ from those of the pregnant women at the onset of pregnancy (70.5+/-36.4). Over the entire pregnancy period these ratios declined significantly (P<0.001) and lower values were found at the end of gestation and after birth (49.6+/-22.4). The cGMP/creatinine (micromol/mol) and DMA/creatinine ratios (mmol/mol) changed parabolically (P<0.001). The maxima of 68.0+/-19.9 and of 4.95+/-1.01 were found at week 20 and 16, respectively. These ratios declined to 45.2+/-17.7 and to 4.03+/-0.83 at the end of gestation but not further during parturition (39.6+/-17.2 and 4.01+/-1.90). The lowest cGMP/creatinine ratios occurred one month after birth (27.4+/-15.7) while in the non-pregnant women the value was 15.3+/-6.2 microM/M. The lowest DMA/creatinine ratios, measured one month after birth (3.41+/-1.28 mmol/mol) were similar to those of the non-pregnant women (3.75+/-0.39 mmol/mol). Positive instead of negative relationships were found between the DMA results and those of the cGMP (P<0.001) and NOx determinations (P<0.05). CONCLUSIONS: (1) The gestational changes of the urinary NOx/creatinine and especially of the GMP/creatinine ratio reflect most likely changes in vascular resistance. (2) Because of the variability of the results between but also within women, these ratios are useless to monitor supposed changes in NO production during parturition.

Adult↗
PubMed1999

Electromyographic findings in shoulder dislocations and fractures of the proximal humerus: comparison with clinical neurological examination.

There is no consensus of opinion about the frequency of associated nerve lesions in anterior shoulder dislocations and fractures of the proximal humerus. We undertook a prospective study to assess the incidence, the severity of the nerve injury and the diagnostic value of electromyographic examination; 215 patients were included. We performed neurological examination and needle electromyography (EMG). Nerve injury was graded according to a denervation score at the EMG. EMG disorders were seen in 133 patients (62%). Testing of sensibility and clinical reflexes proved not to be a reliable indicator for EMG abnormalities. Detection of axonal lesions by grading muscle strength based on the MRC score after these shoulder traumas is difficult. The findings of this study imply that by clinical examination alone a large number of axonal lesions remain undetected.

Adolescent↗
PubMed1999

Early predictors of transplant-related mortality (TRM) after allogeneic bone marrow transplants (BMT): blood urea nitrogen (BUN) and bilirubin.

Transplant-related mortality (TRM) following allo- geneic bone marrow transplantation (BMT) remains a major concern and early identification of patients at risk may be clinically relevant. In this study we describe a predictive score based on bilirubin and blood urea nitrogen (BUN) levels on day +7 after BMT. The patient population consisted of 309 consecutive patients who underwent BMT from sibling (n = 263) or unrelated donors (n = 46) for hematologic disorders between December 1990 and December 1996. Of 27 laboratory tests taken on day +7 after BMT, serum bilirubin (P = 0.02) and BUN (P = 0.007) were found to be independent predictors of TRM in multivariate analysis. The median levels of bilirubin (0.9 mg/dl) and of BUN (21 mg/dl) were then used as a cut-off and a score of 1 was given for values equal/greater than the median. There were 216 patients with scores 0-1 (low risk) on day +7 (bilirubin <0.9 and/or BUN <21) and 93 patients with score 2 (high risk) (bilirubin >/=0.9 and BUN >/=21): the latter had more grade III-IV acute graft-versus-host disease (P = 0.03), slower neutrophil (P = 0.02) and slower platelet engraftment (P = 0.002). The actuarial 5 year TRM is 22% for low risk vs44% for high risk patients (P = 0.0003). For HLA-identical siblings TRM is 20% vs35% (P = 0.01), for unrelated donors it is 20% vs 65% (P = 0.01). Day +7 score was highly predictive of TRM on multivariate analysis (hazard ratio 1.9, P < 0.01), after adjustment for year of transplant (P < 0.00001), unrelated vs sibling donors (P = 0.001), patient age (P = 0.01) and diagnosis (P = 0.01). These results were validated on an independent group of 82 allogeneic BMT recipients in a pediatric Unit who showed an actuarial TRM of 16% for low risk vs 46% for high risk patients (P = 0.002). This study suggests that it may be possible to identify patients with different risks of TRM on day +7 after BMT: high risk patients could be eligible for programs designed to intensify prophylaxis of post-transplant complications.

Adolescent↗
PubMed1999

Diffusion of dialkylnitrosamines into the rat esophagus as a factor in esophageal carcinogenesis.

To indicate how readily nitrosamines (NAms) diffuse into the esophagus, we measured diffusion rate (flux) through rat esophagus of dialkyl-NAms using side-by-side diffusion apparatuses. Mucosal and serosal flux at 37 degrees C of two NAms, each at 50 microM, was followed for 90 min by gas chromatography-thermal energy analysis of NAms in the receiver chamber. Mucosal flux of one or two NAms at a time gave identical results. Mucosal flux was highest for the strong esophageal carcinogens methyl-n-amyl-NAm (MNAN) and methylbenzyl-NAm. Mucosal esophageal flux of 11 NAms was 18-280 times faster and flux of two NAms through skin was 13-28 times faster than that predicted for skin from the molecular weights and octanol:water partition coefficients, which were also measured. Mucosal: serosal flux ratio was correlated (P < 0.05) with esophageal carcinogenicity and molecular weight. For seven NAms tested for carcinogenicity by Druckrey et al. [(1967) Z. Krebsforsch., 69, 103-201], mucosal flux was correlated with esophageal carcinogenicity with borderline significance (P = 0.07). The MNAN:dipropyl-NAm ratio for mucosal esophageal flux was unaffected when rats were treated with phenethylisothiocyanate and was similar to that for forestomach, indicating no involvement by cytochromes P450. Mucosal esophageal flux of MNAN and dimethyl-NAm was reduced by >90% on enzymic removal of the stratum corneum, was unaffected by 0.1 mM verapamil and was inhibited 67-94% by 1.0 mM KCN and 82-93% by 0.23% ethanol. NAm flux through rat skin and jejunum was 5-17% of that through esophagus. Flux through skin increased 5-13 times after enzymic or mechanical removal of the epidermis; the histology probably explained this difference from esophagus. Hence, NAms could be quite rapidly absorbed by human esophagus when NAm-containing foods or beverages are swallowed, the esophageal carcinogenicity of NAms may be partly determined by their esophageal flux and NAm flux probably occurs by passive diffusion.

Animals↗
PubMed1999

Broadband dielectric spectroscopy on glass-forming propylene carbonate.

Dielectric spectroscopy covering more than 18 decades of frequency has been performed on propylene carbonate in its liquid and supercooled-liquid state. Using quasioptic submillimeter and far-infrared spectroscopy, the dielectric response was investigated up to frequencies well into the microscopic regime. We discuss the alpha process whose characteristic time scale is observed over 14 decades of frequency and the excess wing showing up at frequencies some three decades above the peak frequency. Special attention is given to the high-frequency response of the dielectric loss in the crossover regime between alpha peak and boson peak. Similar to our previous results in other glass-forming materials, we find evidence for additional processes in the crossover regime. However, significant differences concerning the spectral form at high frequencies are found. We compare our results to the susceptibilities obtained from light scattering and to the predictions of various models of the glass transition.

Journal Article↗
PubMed1999

The incidence of nerve injury in anterior dislocation of the shoulder and its influence on functional recovery. A prospective clinical and EMG study.

Opinion varies as to the incidence of nerve lesions in anterior dislocation of the shoulder after low-velocity trauma. Most studies are retrospective or do not use EMG. We have investigated the incidence and the clinical consequences of nerve lesions in a prospective study by clinical and electrophysiological examination. Axonal loss was seen in 48% of 77 patients. The axillary nerve was most frequently involved (42%). Although recovery as judged by EMG and muscle strength was almost complete, function of the shoulder was significantly impaired in patients with lesions of the axillary and suprascapular nerves. Unfavourable prognostic factors are increasing age and the presence of a haematoma. It is not necessary to carry out EMG routinely; an adequate programme of physiotherapy is important. In patients with a severe paresis, EMG is essential after three weeks.

Adolescent↗
PubMed1998

Endovaginal ultrasound to exclude endometrial cancer and other endometrial abnormalities.

CONTEXT: Postmenopausal vaginal bleeding is a common clinical problem. Endovaginal ultrasound (EVUS) is a noninvasive diagnostic test that may help determine which women should undergo endometrial biopsy. OBJECTIVE: To determine the accuracy of EVUS in detecting endometrial disease in postmenopausal women with vaginal bleeding according to hormone replacement use. DATA SOURCES: Literature search of English-language and non-English-language articles published from 1966 through November 1996 using MEDLINE and by a manual search of bibliographies of published articles. STUDY SELECTION: Studies were included if they prospectively collected EVUS measurements of endometrial thickness prior to obtaining endometrial tissue for histologic evaluation in postmenopausal women with vaginal bleeding. Of 85 studies that included data on EVUS and endometrial histology, 35 were included in the meta-analysis and included 5892 women. DATA EXTRACTION: Articles were reviewed and independently selected and abstracted by 2 reviewers. Disagreement was resolved by consensus. DATA SYNTHESIS: The overall summary mean weighted estimates of sensitivity and specificity were calculated for thresholds of endometrial thickness from 3 to 10 mm. Using a 5-mm threshold to define abnormal endometrial thickening, 96% (95% confidence interval [CI], 94%-98%) of women with cancer had an abnormal EVUS result, whereas 92% (95% CI, 90%-93%) of women with endometrial disease (cancer, polyp, or atypical hyperplasia) had an abnormal result. This did not vary by hormone replacement use. However, the number of women with normal histology who had an abnormal EVUS result did vary by hormone replacement use. In women who were not using hormone replacement therapy, 593 (8%) with normal histological findings had an abnormal EVUS result (specificity, 92%; 95% CI, 90%-94%), whereas 1544 (23%) using hormone replacement therapy had an abnormal EVUS result (specificity, 77%; 95% CI, 75%-79%). For a postmenopausal woman with vaginal bleeding with a 10% pretest probability of endometrial cancer, her probability of cancer is 1% following a normal EVUS result. CONCLUSION: Endovaginal ultrasound has a high sensitivity for detecting endometrial cancer and other endometrial disease and can reliably identify postmenopausal women with vaginal bleeding who are highly unlikely to have significant endometrial disease so that endometrial sampling may be unnecessary.

Biopsy↗
PubMed1998

Rotator cuff repair during shoulder arthroplasty in rheumatoid arthritis.

A prospective study of 40 shoulder arthroplasties in patients with rheumatoid arthritis was performed to evaluate the results of rotator cuff repair at the time of arthroplasty. A large cuff tear was present in 21 shoulders, and good repair of the cuff was performed in 9. In the other shoulders the repair was considered insufficient. All patients were clinically evaluated using the Hospital for Special Surgery 100-point scoring system. The minimum follow-up period for inclusion in this study was 2 years. The quality of the repair of the ruptured cuff at the time of surgery had a significant influence on the postoperative clinical score (linear regression model, P = .002). The clinical score of the shoulders with good repair of the rotator cuff improved considerably and continued to improve even after the first-year follow-up examination. Meticulous repair of the ruptured cuff at the time of arthroplasty is recommended.

Adult↗