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Biomedical subjects

R Adams

Publications and source records attributed to R Adams.

At least 73 records · Page 4Linked to original sources
PubMed1998

Bone mineral density in children with myelomeningocele.

BACKGROUND: Difficulties with ambulation in patients with myelomeningocele often lead to physical inactivity, osteoporosis, and subsequent development of pathologic fractures. OBJECTIVE: The purpose of this study was to examine bone mineral density and biochemical markers of bone metabolism in patients with myelomeningocele. DESIGN AND METHODS: A total of 35 patients between 6 and 19 years of age with myelomeningocele (ambulatory and nonambulatory) were randomly chosen at the Texas Scottish Rite Hospital for Children. We measured bone mineral density of the distal radius in these patients using single photon absorptiometry and measured the biochemical markers of bone metabolism including parathyroid hormone, 1,25 vitamin D, osteocalcin, urinary pyridinolines/deoxypyridinolines, and urinary calcium excretion. RESULTS: Bone mineral density of the distal radius in the patients with myelomeningocele was approximately 1 to 2 standard deviation units below the mean of the normal population. There were no significant differences between ambulators and nonambulators. However, bone mineral density of the 8 patients who suffered multiple fractures (19) was significantly lower than that for those remaining patients without fractures. Elevated urinary pyridinoline levels, which indicate elevated bone reabsorption, were found more frequently in both non- and limited ambulators than in full-time ambulators. Urinary calcium excretion also was greater than twofold higher in nonambulatory patients versus ambulatory patients. There were no other differences in the biochemical markers of bone metabolism (osteocalcin, parathyroid hormone, 1,25 vitamin D, and urinary deoxypyridinolines) between ambulators and nonambulators. Bone mineral density rises in normal growing children 6 to 19 years of age. When the boys and girls were considered separately, bone mineral density rises with age in boys, but not in girls. CONCLUSION: Patients with myelomeningocele have decreased bone mineral density and are at risk of suffering pathologic bone fractures. The measurement of bone mineral density may help to identify those patients at greatest risk of suffering multiple fractures. The urinary calcium excretion of nonambulators was higher than that of ambulators and likely contributes to their decreased bone mineral density. Bone mineral density increases with age in boys, but not in girls.

Adolescent↗
PubMed1998

Clinical tests for ankle syndesmosis injury: reliability and prediction of return to function.

Despite the severity of ankle syndesmosis injuries, it has been argued that they are relatively poorly detected. This study investigated the interrater reliability of four orthopaedic tests for ankle syndesmosis injury and assessed their ability to predict the extended recovery times that have been reported as a consequence of this injury. Nine physiotherapists, working in random pairings, examined 53 subjects, all receiving treatment for ankle injury at two private clinics. Each subject was tested by two physiotherapists who independently performed the palpation test, external rotation test, squeeze test, and dorsiflexion-compression test. Kappa coefficient testing indicated that the external rotation test had the best interrater reliability (kappa = 0.75). The squeeze test was found to have moderate reliability (kappa = 0.50), and the palpation and dorsiflexion-compression tests both had only fair reliability (kappa = 0.36). The degree of pair-wise association between the results of the four tests was low (phi < or = 0.30 for all test combinations), suggesting that if all four tests were performed on the same subject, it was not likely that they would achieve similar results. Follow-up interviews were conducted to determine the time taken for subjects to walk 10 m without pain and, for sports injuries, the time taken to return to training and then to competition. For each test, Mann-Whitney U values showed no significant difference between the recovery times of subjects with positive or negative test results, although subjects with recovery times markedly longer than normal were detected by three of the four tests. When an either/or combination of the external rotation and dorsiflexion-compression tests was considered, subjects with a positive test result took significantly longer to return to playing sports.

Adolescent↗
PubMed1998

Consumerism as a branding opportunity.

Managing a customer portfolio at the individual level is the most difficult and most promising endeavor. An individual level consumer portfolio does not mean creating marketing materials and advertising campaigns customized for every member of your health plan. What it does mean is developing segmentation models based on consumer preferences extracted directly from your members, not socioeconomic or other demographic models. The most important information to extract is perceptions on how much and what kind of value members want from the organization.

Aged↗
PubMed1998

Cementless revision of total hip arthroplasty using proximal porous-coated femoral implants.

Thirty patients had 32 cementless total hip arthroplasty revisions and were evaluated postoperatively for clinical function (Harris Hip Score) and radiographic evidence of implant stability. Of the 26 femoral components revised, 16 were revised with anatomic long-stem femoral prostheses, and 10 were revised with straight mid-stem-length components. All components were collared and had circumferential proximal fiber-mesh porous coating. Seven of 16 patients had radiographic subsidence after revision with long-stem components (2 to 30 mm); 6 of 10 patients had subsidence after revision with mid-stem femoral components (2 to 25 mm). Of the 13 patients with femoral subsidence, 8 had calcar reconstruction with allograft bone; of the 13 patients without radiographic subsidence, 8 did not require calcar reconstruction. One of 27 fiber-mesh, porous-coated acetabular components migrated (30 mm). No components have been removed or revised. Even with circumferential proximal porous coating, femoral implant stability remains unpredictable in total hip arthroplasty revision.

Adult↗
PubMed1997

Posteroanterior stiffness in the lumbosacral spine. The correlation between adjacent vertebral levels.

STUDY DESIGN: A descriptive design of posteroanterior stiffness in the lumbosacral spine. OBJECTIVES: To measure posteroanterior stiffness between L1 and S1 to establish the pattern of stiffness in individuals with no history of low back pain. SUMMARY OF BACKGROUND DATA: In clinical examination for low back pain, manual assessment of abnormal stiffness is used to determine the site of the pain-producing lesion. However, there is little objective evidence of the variation in stiffness between levels in normal spines or of the factors that determine posteroanterior stiffness. METHOD: Posteroanterior stiffness was measured with a specially developed measuring device at each of the six vertebral levels between L1 and S1. Force-displacement relations were computed for each vertebral level. The gradient of the linear part of the force-displacement relation was used as a coefficient of stiffness, and the amount of displacement between 5 N and 30 N of applied force (D5-30) was used as a measure of the length of the toe region. RESULTS: Overall there was a significant linear trend of increasing stiffness from L1 to S1. Ninety percent of the difference scores for adjacent level comparisons were less than 3.6 N/mm. There was considerable variation in the patterns of stiffness found in different individuals. The stiffness coefficient and D5-30 correlated significantly with skinfold thickness measurements and body mass index. CONCLUSION: A linear trend of increasing stiffness was found between L1 and S1, but this pattern was influenced by variables related to body type (adiposity).

Adult↗
PubMed1997

Apoptotic cell death in neuronal differentiation of P19 EC cells: cell death follows reentry into S phase.

Apoptotic cell death was observed during aggregate culture of the mouse embryonal carcinoma cell line P19 exposed to all-trans retinoic acid (tRA). This finding was confirmed by genomic DNA agarose gel electrophoresis and transmission electron microscopy. Apoptosis was associated with P19 cell neuronal differentiation; alternative causes of cell death, i.e., cavitation-related, cytotoxicity of tRA, or spontaneous cell death were excluded. Analysis by flow cytometry revealed that the apoptosis was likely to occur in multiplying cells that underwent to reentering into S phase. We therefore examined 5-bromo-2'-deoxyuridine (BrdU) incorporation and proliferating cell nuclear antigen (PCNA) expression and localization in the aggregates by immunofluorescent staining. Although the P19 cells in the aggregates exposed to tRA incorporated BrdU at an equivalent level to those not exposed to tRA, the cells showed diminished PCNA expression and nuclear accumulation. We propose that P19 apoptosis during neuronal differentiation is a model system in which programmed cell death occurs simultaneously with cell division leading to differentiation.

Animals↗
PubMed1997

Mitogenic lectin concanavalin A induces calvarial bone formation in vivo via indomethacin-sensitive pathway.

Natural products such as plant lectins have not been extensively surveyed for their potential as anabolic agents. Wlodarski (1991) observed that the lectin Concanavalin A (ConA) has chondrogenic and osteogenic activity following local injection over the mouse tibia. To gain more insight into the mechanism of ConA in bone, we investigated and quantitated the effects of ConA injected locally over the mouse calvaria in vivo. ConA was injected subcutaneously over the calvaria of mice at 2, 10, and 20 microg per injection, four times a day, for three consecutive days. By day fourteen, a layer of new woven bone 30 microm thick had been laid down on the periosteal surface, resulting in a 36% increase in calvarial thickness (as compared with 2% in vehicle-treated controls). ConA also increased periosteal width and osteoblast surface in a dose-dependent manner. Concurrent administration of indomethacin (30 microg) with ConA (20 microg), four times a day for 3 days, strongly inhibited new bone formation. With a single injection of ConA (80 microg) over the calvaria, osteoclastic bone resorption and proliferation of osteoblast precursors and periosteum increased at day four, but showed a decrease at later times (14 and 28 days after injection). Except at the earliest time, there was little evidence of osteoclastic bone resorption. New bone width increased linearly over 28 days. In summary, ConA induced new bone formation in a pattern comparable with that of aFGF and bFGF, potent stimulators of calvarial bone formation (Dunstan, 1993), and this osteogenic effect was caused by an indomethacin-sensitive pathway.

Animals↗
PubMed1997

Effects of human tumor cell lines on local new bone formation in vivo.

Although some tumors cause osteolytic lesions, there are some that stimulate new bone formation. This is an important phenomenon because the responsible mechanisms probably represent an aberration of normal physiological bone formation, and identifying the factors involved in the process may lead to new therapies for various bone diseases. To clarify our understanding of the potential mechanism responsible, we compared and quantitated the extent of new bone formation stimulated by human tumors (HeLa, Hep-2, AV-3, FL, WISH and KB), some of which have osteogenic activity in vivo [2]. Tumor cells were injected over the calvaria of nude mice to examine formation of new bone. The tumor cells produced three histologically distinct patterns of new bone growth: (1) WISH and KB stimulated appositional bone growth adjacent to periosteal bone surfaces; (2) HeLa and Hep2 induced new bone growth over calvarial surface even when distant from the tumor mass; (3) FL stimulated bone formation adjacent to periosteum as well as ectopic bone formation in sites distant from bone. All tumors except AV3 induced mean new bone thickness >100 microm, and Hep-2 cells produced bone 330 microm thick. PCR and Northern blot analysis of mRNA isolated from cultured tumor cells revealed that all cell lines expressed mRNA for TGFbeta, (fibroblast growth factor) FGF-1, FGF-2, and IGF-I, and most cell lines produced mRNA for PDGF. Only FL expressed large amounts of mRNA for BMP2. In serum-free conditioned media from Hep2 and HeLa cells purified by heparin affinity chromatography, we have identified FGF-I, FGF-2, and PDGF by immunodetection with specific antibodies. Our results show that new bone growth caused by these tumors is likely due to the production of bone growth factors by the tumor cells, and that the overall effects on bone may be due to several factors working in concert.

Animals↗
PubMed1997

Myelodysplastic syndrome presenting with clonal rearrangement isolated to chromosomal region 1q.

Myelodysplastic syndrome (MDS) is a malignant hematologic disorder that may present with clinical features consistent with the diagnosis of severe aplastic anemia (SAA). Distinguishing the two disorders may depend on the presence of a clonal chromosomal abnormality. In the following, we report a case of MDS associated with what we believe to be a previously unreported clonal abnormality of chromosome 1q, a finding that enabled us to distinguish between MDS and SAA.

Adult↗
PubMed1997

The value of the lipid-laden macrophage index in the assessment of aspiration pneumonia.

BACKGROUND: A semi-quantitative index of lipid-laden macrophages on broncho-alveolar lavage (BAL) has been reported to be highly sensitive but only moderately specific for aspiration in adults. There has been little published literature evaluating this technique since the original report. AIMS: To assess the value of a lipid-laden macrophage index (LLMI) of greater than 100 to confirm the clinical diagnosis of aspiration in patients with abnormal radiological investigations. METHODS: Prospective evaluation of 80 adult patients with abnormal radiology was undertaken using BAL and the LLMI. A diagnosis of aspiration was made prior to bronchoscopy if the patient had one or more of: clinically witnessed aspiration, positive barium swallow or speech pathology assessment; or an upper gastrointestinal endoscopy showed severe reflux oesophagitis and the patient had a history consistent with aspiration. RESULTS: Eighteen patients were diagnosed with aspiration. Of these, 17 had an index > 100, and one had an index of 94 (mean 157, 99% CI 127-187, range 94-238). Of the other 62 subjects, seven had an index > 100 (mean 46, 99% CI 22-70, range 0-303). There was a significant difference between index scores for the two groups (p = 0.002). For aspiration, an index > 100 had a sensitivity of 94% and a negative predictive value of 98%. The specificity was 89%, with a positive predictive value of 71%. CONCLUSIONS: The LLMI is a sensitive indicator for aspiration causing radiological lung disease in adults. Its lack of specificity means it cannot be the sole means of diagnosis, but it can allow better targeting of other investigations in those patients in whom bronchoscopy is undertaken to investigate radiological abnormalities.

Adult↗
PubMed1997

Asthma prevalence, morbidity and management practices in South Australia, 1992-1995.

BACKGROUND: The Spring South Australian Health Omnibus Survey (SSAHOS) has been used to monitor trends in asthma prevalence, asthma morbidity and asthma management practices between 1992 and 1995. AIMS: To determine if self-reported asthma prevalence and availability of asthma action plans were increasing. To identify deficiencies in asthma management and opportunities for intervention. METHODS: Representative population survey by trained interviewers using a multistage, systematic, clustered area sample of 4200 households in South Australia where people aged 15 years or more are living. RESULTS: Over 3000 interviews were conducted each year. Between 1992 and 1995 the self-reported prevalence of asthma in those aged 15 years or more increased significantly from 15.7% to 20.3% (p < 0.0005), and the prevalence of current asthma increased from 9.3% to 11.4% (p < 0.05). The self-reported availability of individual asthma action plans increased from 21.9% in 1992 to 42.2% in 1995 (p < 0.0005). In 1992, 21% had a nebuliser at home, and 10.5% had a peak flow meter. In 1993, 61.4% were using preventive medications, and 35% thought bronchodilators were 'preventer' medications. In 1994 and 1995, between 12.5% and 15.6% had nocturnal awakening weekly or more often, and 31.4% had morning asthma symptoms weekly or more often. Between 20.1% and 20.8% had lost days from usual activities during the last year. Those on incomes below $20,000 had more symptoms, had more admissions to hospital, and required more medication than those on higher incomes. CONCLUSIONS: Self-reported asthma prevalence has increased. There remains a gap between current asthma management and that recommended by the National Asthma Campaign.

Adolescent↗
PubMed1997

Serum creatinine is a poor marker of glomerular filtration rate in patients with spina bifida.

Serum creatinine is used to estimate the glomerular filtration rate (GFR). The serum creatinine, however, may not accurately reflect the GFR in spina bifida patients, who often have decreased overall muscle mass resulting from spinal cord abnormalities. The relationship between the serum creatinine and GFR (obtained by [(125)I]iothalamate clearance) was examined in a population of spina bifida patients. Age-matched patients without spina bifida were used as controls. Results demonstrate that, for serum creatinines above 0.5 mg/dL, serum creatinine is a very poor predictor of GFR. Two patients with serum creatinines of 2.2 mg/dL are near end-stage renal disease with GFRs of 12.5 and 13 mL/minute per 1.73m2 and two patients were initiated on dialysis at the conclusion of the study. It is concluded that obtaining a GFR from a clearance study and not serum creatinine is the only reliable method to assess renal function in spina bifida patients once the serum creatinine is greater than 0.5 mg/dL.

Adolescent↗
PubMed1997

Interleukin 8 released after acute myocardial infarction is mainly bound to erythrocytes.

OBJECTIVE: To determine whether rapid clearance of interleukin 8 (IL-8) from plasma through binding to the erythrocyte chemokine receptor may be responsible for failure to detect IL-8 consistently after acute myocardial infarction. DESIGN: Plasma concentrations of IL-8 were measured at frequent intervals in 43 consecutive patients. In 21 of these, erythrocyte bound IL-8 concentrations were also measured. The influence of infarct size, type of treatment, and the presence of early successful reperfusion on IL-8 release was assessed. RESULTS: Peak IL-8 concentrations in plasma were raised in 31 of the 43 patients (68%). Median plasma IL-8 concentrations were 16.0 pg/ml (range 2.4 to 225.0 pg/ml) six hours after the onset of chest pain. Twelve hours after the onset of symptoms, plasma IL-8 concentrations had already returned to normal in 27 patients. In contrast, in 18 of 21 patients (86%), erythrocyte bound IL-8 concentrations were raised at between 6 and 30 hours, with a median peak value of 59.8 pg/ml (range 19 to 148 pg/ml). No correlation between peak creatine kinase MB and peak IL-8 (plasma or erythrocyte bound) was observed. There was a significant difference in peak plasma IL-8 concentrations between patients who underwent direct PTCA (19.4 pg/ml) and those who received conservative treatment (9.9 pg/ml; p = 0.0206), but no correlation with the presence of early successful reperfusion. CONCLUSIONS: IL-8 is released in plasma after acute myocardial infarction and subsequently binds to red blood cells, resulting in only a transient rise of plasma IL-8 and a more prolonged increase of erythrocyte bound IL-8.

Biomarkers↗
PubMed1997

Semiconstrained total elbow replacement for the treatment of post-traumatic osteoarthrosis.

Forty-one consecutive patients were managed for post-traumatic osteoarthrosis or dysfunction of the elbow with use of a non-customized semiconstrained Coonrad-Morrey total elbow prosthesis. The average age at the time of the operation was fifty-seven years (range, thirty-two to eighty-two years). The patients were followed for an average of five years and eight months (range, two to twelve years). Radiographs were made at least two years postoperatively (average, five years and one month; range, two to twelve years) for thirty-nine of the forty-one patients. According to the Mayo elbow performance score, sixteen patients (39 per cent) had an excellent result, eighteen (44 per cent) had a good result, five (12 per cent) had a fair result, and two (5 per cent) had a poor result. Thirty-six (95 per cent) of the thirty-eight patients who had a functioning implant at the time of follow-up considered the outcome to be satisfactory. Preoperatively, thirty-seven patients (90 per cent) had moderate or severe pain; postoperatively, thirty (73 per cent) had no or only mild discomfort. Motion improved from an average arc of flexion of 40 to 118 degrees preoperatively to an average arc of flexion of 27 to 131 degrees postoperatively. All thirty-eight functioning implants rendered the elbow stable. Eleven patients (27 per cent) had a major complication. Nine of them (22 per cent of the series) needed an additional operation. There was no aseptic loosening, and most of the complications were primarily due to so-called mechanical failure. The ulnar component fractured in five patients (12 per cent), and the polyethylene bushings wore out in two (5 per cent). These complications were attributed principally to the performance of strenuous physical labor, such as lifting more than ten kilograms on a regular basis, against the advice of the surgeon; excessive preoperative deformity of the joint; or an unstable traumatic injury. Two patients (5 per cent) had an infection. Semiconstrained joint replacement of the elbow can be a reliable form of treatment, and frequently is the only viable option, for the difficult problems encountered with post-traumatic destruction of a joint. Restoration of function, relief of pain, and patient satisfaction can be achieved even when a patient is less than sixty years old if that patient has low demands and a low level of activity. However, the mechanical failures underscore the fact that this procedure is relatively contraindicated in patients who anticipate strenuous physical activity or who are not expected to comply with the postoperative protocol. This observation reflects the tendency for increased and excessive use of a previously functionless joint, after it has been rendered stable and pain-free, to lead to mechanical failure.

Adult↗
PubMed1997

Plinth padding and measures of posteroanterior lumbar stiffness.

OBJECTIVE: To investigate whether measurement of posteroanterior (PA) lumbar stiffness is affected by the presence of padding on the testing plinth. DESIGN: Within a repeated-measures design, measurements were made of lumbar PA stiffness in subjects without low back pain on both a rigid and a padded plinth surface. SUBJECTS: Nineteen subjects with no history of any low back pain requiring treatment over the preceding 12 months participated in this study. METHODS: PA stiffness was measured at L3 on two occasions under two different conditions. The first condition involved measurement of lumbar stiffness on a rigid plinth surface; the second involved measurement on a padded plinth surface. A reliable mechanical device was used to obtain the PA stiffness measures. RESULTS: Mean lumbar PA stiffness values obtained when testing on a padded plinth were 2.86 N/mm less than those values obtained when testing the same lumbar spines on a rigid plinth. A paired t test showed a significant difference between the PA stiffness measures at L3 obtained on the padded plinth and those obtained on the rigid plinth (t = 6.66, df = 18, p < or = .0001). CONCLUSIONS: These findings suggest that to improve the reliability of lumbar PA stiffness assessment, testing should be performed under the same plinth surface conditions.

Adult↗
PubMed1996

Treatment of Budd-Chiari syndrome with portosystemic shunt or liver transplantation.

BACKGROUND: Budd-Chiari syndrome is an uncommon disorder caused by obstruction to hepatic venous outflow, causing varying degrees of hepatic injury depending on the extent, severity, and acuity of the obstruction. PATIENTS AND METHODS: We reviewed the indications for operative intervention and the results of treating 32 patients with Budd-Chiari syndrome seen at Toronto Hospital between 1968 and 1995. RESULTS: Twenty-one patients underwent portosystemic shunt (PSS) and 7 patients underwent liver transplantation (LT) as their initial operative management. Three patients who initially had PSS subsequently required LT. Patients with cirrhosis found on biopsy and preservation of hepatocellular function were treated with PSS and showed no difference in outcome when compared with patients without cirrhosis (P = 0.35). Patients who were treated by PSS with retrohepatic vena caval compression, as shown by high caval gradients had outcomes similar to those for patients with low gradients (P = 0.31). Using the Kaplan-Meier method, 5-year survival of PSS patients was 57%. Liver transplantation was used to manage patients with hepatic decompensation, as well as patients with vena caval occlusion or failed PSS. The 5-year Kaplan-Meier survival for LT was 67%. CONCLUSIONS: Both PSS and LT are effective options in the management of Budd-Chiari syndrome. Portosystemic shunt is the preferred initial approach even with cirrhosis or retrohepatic caval compression as long as there is preservation of liver function and a patent vena cava. Liver transplantation should be used as primary therapy for patients with irreversible hepatic decompensation or vena caval occlusion, and it can be an effective salvage procedure following failed PSS.

Adolescent↗
PubMed1996

Stroke rehabilitation: are highly structured units more conducive to physical activity than less structured units?

OBJECTIVE: To determine if the physical design and organizational structure of rehabilitation units is related to the amount of patients' motor activity. DESIGN: An observational study was conducted; time samples of the motor activity of patients following stroke were taken between 7AM and 7PM both on weekdays and weekends. SETTING: Two rehabilitation units associated with general hospitals with different physical design and organizational structure. One unit was spread over a large area and had a highly organized daily structure; the other was small and informally organized. SUBJECTS: Inpatients with hemiplegia as a result of stroke who gave consent to participate. MAIN OUTCOME MEASURE: The nature and frequency of 14 motor activities were compared between units. RESULTS: No significant difference was found in any of the observed motor activities between the units when using independent groups t tests (p = 0.1-0.8). Subjects in both units spent more than 70% of their day in activities largely unrelated to physical outcome (eg, conversing with visitors or doing nothing observable) and less than 20% of the day in activities that could potentially contribute to their recovery (eg, in therapy or exercising independently). CONCLUSIONS: Rehabilitation units are not functioning as learning environments. The challenge is to identify and implement measures that will change this finding.

Aged↗