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D P Martin

Publications and source records attributed to D P Martin.

At least 37 records · Page 2Linked to original sources
PubMed2001

Forced recombination between distinct strains of Maize streak virus.

Recombination between divergent virus genomes is believed to be a major mechanism for generation of novel virus genotypes. We have examined the recombination process in geminiviruses by forcing recombination between two distinct isolates of Maize streak virus (MSV), MSV-Kom and MSV-Set. Heterodimeric agroinfectious constructs containing tandemly cloned mixtures of complete or partial MSV-Set and MSV-Kom genomes were used to simulate a circular dimeric form similar to that which would be expected to occur following a single intermolecular crossing-over event between MSV-Set and MSV-Kom replicative form DNAs at the long intergenic region (LIR)-movement protein gene (MP) interface. We isolated, analysed and biologically characterized many of the recombinant MSV genomes that were generated from the constructs in planta. Apart from having the same simulated breakpoint at the LIR-MP interface, all the genomes examined had a second breakpoint that had been generated through either intramolecular homologous recombination or a replicational release mechanism. The pathogenicities of six predominantly MSV-Kom-like recombinants were tested in maize. While all were capable of producing a symptomatic infection in this host, none was more virulent than MSV-Kom and only two were more virulent than MSV-Set. The two most virulent recombinants were leafhopper transmitted to a range of differentially MSV-resistant maize, wheat and barley genotypes and both were found to have unique biological properties.

Base Sequence↗
PubMed2001

Development of a homogeneous MAP kinase reporter gene screen for the identification of agonists and antagonists at the CXCR1 chemokine receptor.

Agonist activity at G protein-coupled receptors (GPCRs) that regulate heterotrimeric G proteins of the Galpha(i/o) or Galpha(q) families has been shown to result in activation of the mitogen-activated protein (MAP) kinase cascade. To facilitate compound screening for these classes of GPCR, we have developed a reporter gene that detects the activation of the ternary complex transcription factor Sap1a following MAP kinase activation. In contrast to other reporter gene assays for Galpha(i/o)-coupled GPCRs, the MAP kinase reporter generates an increase in signal in the presence of agonist. The reporter gene has been transfected into Chinese hamster ovary cells to generate a "host" reporter gene-containing cell line. The Galpha(i)-coupled human CXCR1 chemokine receptor was subsequently transfected into this cell line in order to develop a 384-well format screen for both agonists and antagonists of this receptor. Agonists activated the reporter gene with the expected rank order of potency and with similar concentration dependence as seen with the regulation of other signal transduction cascades in mammalian cells: interleukin-8 (IL-8) (pEC(50) = 7.0 +/- 0.1) > GCP-2 (pEC(50) = 6.3 +/- 0.1) > NAP-2 (pEC(50) < 6). CXCR1-mediated activation of MAP kinase was inhibited by pertussis toxin and the MEK inhibitor PD98059, demonstrating that receptor activation of MAP kinase is due to pertussis toxin-sensitive Galpha(i/o)-family G proteins to cause the activation of MEK kinase. Using the 384-well format, assay performance was unaffected by solvent concentrations of 0.5% ethanol, 0.15% glycerol, or 1% DMSO. Signal crosstalk between adjacent wells was less than 1%. The assay exhibited a Z factor of 0.53 and a coefficient of variation of response to repeated application of IL-8 (100 nM) of 15.9%.

Animals↗
PubMed2001

First-birth cesarean and placental abruption or previa at second birth(1).

OBJECTIVE: To assess the association between first-birth cesarean delivery and second-birth placental abruption and previa. METHODS: We conducted a population-based, retrospective cohort analysis using data from the Washington State Birth Events Record Database. The study cohort included all primiparas who gave birth to live singleton infants in nonfederal short-stay hospitals from January 1, 1987, through December 31, 1996, and who had second singleton births during the same period (n = 96,975). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for placental abruption or previa at second births associated with first-birth cesareans. RESULTS: Among our study cohort, abruptio placentae complicated 11.5 per 1000 and placenta previa 5.2 per 1000 singleton deliveries at second births. In logistic regression analyses adjusted for maternal age, women with first-birth cesareans had significantly increased risk of abruptio placentae (OR 1.3, 95% CI 1.1, 1.5), and placenta previa (OR 1.4, 95% CI 1.1, 1.6) at second births, compared with women with prior vaginal deliveries. CONCLUSION: We found moderately increased risk of placental abruption and previa as a long-term effect of prior cesarean delivery on second births.

Abruptio Placentae↗
PubMed2000

Early in vivo experience with tissue-engineered trileaflet heart valves.

BACKGROUND: Tissue engineering is a new approach in which techniques are being developed to transplant autologous cells onto biodegradable scaffolds to ultimately form new functional autologous tissue. Workers at our laboratory have focused on tissue engineering of heart valves. The present study was designed to evaluate the implantation of a whole trileaflet tissue-engineered heart valve in the pulmonary position in a lamb model. METHODS AND RESULTS: We constructed a biodegradable and biocompatible trileaflet heart valve scaffold that was fabricated from a porous polyhydroxyalkanoate (pore size 180 to 240 microm; Tepha Inc). Vascular cells were harvested from ovine carotid arteries, expanded in vitro, and seeded onto our heart valve scaffold. With the use of cardiopulmonary bypass, the native pulmonary leaflets were resected, and 2-cm segments of pulmonary artery were replaced by autologous cell-seeded heart valve constructs (n=4). One animal received an acellular valved conduit. No animal received any anticoagulation therapy. Animals were killed at 1, 5, 13, and 17 weeks. Explanted valves were examined histologically with scanning electron microscopy, biochemically, and biomechanically. All animals survived the procedure. The valves showed minimal regurgitation, and valve gradients were <20 mm Hg on echocardiography. The maximum gradient was 10 mm Hg with direct pressures. Macroscopically, the tissue-engineered constructs were covered with tissue, and there was no thrombus formation on any of the specimens. Scanning electron microscopy showed smooth flow surfaces during the follow-up period. Histological examination demonstrated laminated fibrous tissue with predominant glycosaminoglycans as extracellular matrix. 4-Hydroxyproline assays demonstrated an increase in collagen content as a percentage of native pulmonary artery (1 week 45.8%, 17 weeks 116%). DNA assays showed a comparable number of cells in all explanted samples. There was no tissue formation in the acellular control. CONCLUSIONS: Tissue-engineered heart valve scaffolds fabricated from polyhydroxyalkanoates can be used for implantation in the pulmonary position with an appropriate function for 120 days in lambs.

Absorbable Implants↗
PubMed2000

Functional living trileaflet heart valves grown in vitro.

BACKGROUND: Previous tissue engineering approaches to create heart valves have been limited by the structural immaturity and mechanical properties of the valve constructs. This study used an in vitro pulse duplicator system to provide a biomimetic environment during tissue formation to yield more mature implantable heart valves derived from autologous tissue. METHODS AND RESULTS: Trileaflet heart valves were fabricated from novel bioabsorbable polymers and sequentially seeded with autologous ovine myofibroblasts and endothelial cells. The constructs were grown for 14 days in a pulse duplicator in vitro system under gradually increasing flow and pressure conditions. By use of cardiopulmonary bypass, the native pulmonary leaflets were resected, and the valve constructs were implanted into 6 lambs (weight 19+/-2.8 kg). All animals had uneventful postoperative courses, and the valves were explanted at 1 day and at 4, 6, 8, 16, and 20 weeks. Echocardiography demonstrated mobile functioning leaflets without stenosis, thrombus, or aneurysm up to 20 weeks. Histology (16 and 20 weeks) showed uniform layered cuspal tissue with endothelium. Environmental scanning electron microscopy revealed a confluent smooth valvular surface. Mechanical properties were comparable to those of native tissue at 20 weeks. Complete degradation of the polymers occurred by 8 weeks. Extracellular matrix content (collagen, glycosaminoglycans, and elastin) and DNA content increased to levels of native tissue and higher at 20 weeks. CONCLUSIONS: This study demonstrates in vitro generation of implantable complete living heart valves based on a biomimetic flow culture system. These autologous tissue-engineered valves functioned up to 5 months and resembled normal heart valves in microstructure, mechanical properties, and extracellular matrix formation.

Absorbable Implants↗
PubMed2000

Association between method of delivery and maternal rehospitalization.

CONTEXT: Despite nearly 4 million deliveries in the United States each year, minimal information exists on unintended health consequences following childbirth, particularly in relation to delivery method. OBJECTIVE: To assess the risk for maternal rehospitalization associated with cesarean or assisted vaginal delivery compared with spontaneous vaginal delivery. DESIGN: Retrospective cohort study of data from the Washington State Birth Events Record Database for 1987 through November 1, 1996. SETTING AND PARTICIPANTS: All primiparous women without selected chronic medical conditions who delivered live singleton infants in nonfederal short-stay hospitals in Washington State (N =256,795). MAIN OUTCOME MEASURES: Relative risks (RRs) of rehospitalization within 60 days of cesarean or assisted vaginal vs spontaneous vaginal deliveries. RESULTS: A total of 3149 women (1.2%) were rehospitalized within 60 days of delivery. In logistic regression analyses adjusting for maternal age, rehospitalization was found to be more likely among women with cesarean delivery (RR, 1.8; 95% confidence interval [CI], 1.6-1.9) or assisted vaginal delivery (RR, 1.3; 95% CI, 1.2-1.4) than among women with spontaneous vaginal delivery. Cesarean delivery was associated with significantly increased risks of rehospitalization for uterine infection, obstetrical surgical wound complications, and cardiopulmonary and thromboembolic conditions. Among women with assisted vaginal delivery, significant increased risks were seen for rehospitalization with postpartum hemorrhage, obstetrical surgical wound complications, and pelvic injury. CONCLUSIONS: Women with cesarean and assisted vaginal deliveries were at increased risk for rehospitalization, particularly with infectious morbidities. Effective strategies for preventing and controlling peripartum infection should be an obstetrical priority.

Adult↗
PubMed2000

Tissue engineering of heart valves: in vitro experiences.

BACKGROUND: Tissue engineering is a new approach, whereby techniques are being developed to transplant autologous cells onto biodegradable scaffolds to ultimately form new functional tissue in vitro and in vivo. Our laboratory has focused on the tissue engineering of heart valves, and we have fabricated a trileaflet heart valve scaffold from a biodegradable polymer, a polyhydroxyalkanoate. In this experiment we evaluated the suitability of this scaffold material as well as in vitro conditioning to create viable tissue for tissue engineering of a trileaflet heart valve. METHODS: We constructed a biodegradable and biocompatible trileaflet heart valve scaffold from a porous polyhydroxyalkanoate (Meatabolix Inc, Cambridge, MA). The scaffold consisted of a cylindrical stent (1 x 15 x 20 mm inner diameter) and leaflets (0.3 mm thick), which were attached to the stent by thermal processing techniques. The porous heart valve scaffold (pore size 100 to 240 microm) was seeded with vascular cells grown and expanded from an ovine carotid artery and placed into a pulsatile flow bioreactor for 1, 4, and 8 days. Analysis of the engineered tissue included biochemical examination, enviromental scanning electron microscopy, and histology. RESULTS: It was possible to create a trileaflet heart valve scaffold from polyhydroxyalkanoate, which opened and closed synchronously in a pulsatile flow bioreactor. The cells grew into the pores and formed a confluent layer after incubation and pulsatile flow exposure. The cells were mostly viable and formed connective tissue between the inside and the outside of the porous heart valve scaffold. Additionally, we demonstrated cell proliferation (DNA assay) and the capacity to generate collagen as measured by hydroxyproline assay and movat-stained glycosaminoglycans under in vitro pulsatile flow conditions. CONCLUSIONS: Polyhydroxyalkanoates can be used to fabricate a porous, biodegradable heart valve scaffold. The cells appear to be viable and extracellular matrix formation was induced after pulsatile flow exposure.

Animals↗
PubMed2000

Tissue-engineered valved conduits in the pulmonary circulation.

OBJECTIVE: Bioprosthetic and mechanical valves and valved conduits are unable to grow, repair, or remodel. In an attempt to overcome these shortcomings, we have evaluated the feasibility of creating 3-leaflet, valved, pulmonary conduits from autologous ovine vascular cells and biodegradable polymers with tissue-engineering techniques. METHODS: Endothelial cells and vascular medial cells were harvested from ovine carotid arteries. Composite scaffolds of polyglycolic acid and polyhydroxyoctanoates were formed into a conduit, and 3 leaflets (polyhydroxyoctanoates) were sewn into the conduit. These constructs were seeded with autologous medial cells on 4 consecutive days and coated once with autologous endothelial cells. Thirty-one days (+/-3 days) after cell harvesting, 8 seeded and 1 unseeded control constructs were implanted to replace the pulmonary valve and main pulmonary artery on cardiopulmonary bypass. No postoperative anticoagulation was given. Valve function was assessed by means of echocardiography. The constructs were explanted after 1, 2, 4, 6, 8, 12, 16, and 24 weeks and evaluated macroscopically, histologically, and biochemically. RESULTS: Postoperative echocardiography of the seeded constructs demonstrated no thrombus formation with mild, nonprogressive, valvular regurgitation up to 24 weeks after implantation. Histologic examination showed organized and viable tissue without thrombus. Biochemical assays revealed increasing cellular and extracellular matrix contents. The unseeded construct developed thrombus formation on all 3 leaflets after 4 weeks. CONCLUSION: This experimental study showed that valved conduits constructed from autologous cells and biodegradable matrix can function in the pulmonary circulation. The progressive cellular and extracellular matrix formation indicates that the remodeling of the tissue-engineered structure continues for at least 6 months.

Animals↗
PubMed2000

Perception of dysphonic voice quality by naive listeners.

For clinical assessment as well as student training, there is a need for information pertaining to the perceptual dimensions of dysphonic voice. To this end, 24 naive listeners judged the similarity of 10 female and 10 male vowel samples, selected from within a narrow range of fundamental frequencies. Most of the perceptual variance for both sets of voices was associated with "degree of abnormality" as reflected by perceptual ratings as well as combined acoustic measures, based upon filtered and unfiltered signals. A second perceptual dimension for female voices was associated with high frequency noise as reflected by two acoustic measures: breathiness index (BRI) and a high-frequency power ratio. A second perceptual dimension for male voices was associated with a breathy-overtight continuum as reflected by period deviation (PDdev) and perceptual ratings of breathiness. Results are discussed in terms of perceptual training and the clinical assessment of pathological voices.

Adult↗
PubMed2000

Patch augmentation of the pulmonary artery with bioabsorbable polymers and autologous cell seeding.

OBJECTIVE: In recent years bioabsorbable synthetic or biologic materials have been used to augment the pulmonary artery or the right ventricular outflow tract. However, each of these polymers has one or more shortcomings. None of these patch materials has been seeded with cells. Thus, we have tested a fast-absorbing biopolymer, poly-4-hydroxybutyric acid, with autologous cell seeding for patch augmentation of the pulmonary artery in a juvenile sheep model. METHODS: Vascular cells were isolated from ovine peripheral veins (n = 6). Bioabsorbable porous poly-4-hydroxybutyric acid patches (porosity > 95%) were seeded on 3 consecutive days with a mixed vascular cell suspension (21.3 +/- 1.3 x 10(6) cells). Forty-five (+/- 2) days after the vessel harvest, 1 unseeded and 6 autologously seeded control patches were implanted into the proximal pulmonary artery. The animals received no postoperative anticoagulation. Follow-up was performed with echocardiography after 1 week and before explantation after 1, 7, and 24 weeks (2 animals each) for the seeded control patches and after 20 weeks for the nonseeded control patch. RESULTS: All animals survived the procedure. Postoperative echocardiography of the seeded patches demonstrated a smooth surface without dilatation or stenosis. Macroscopic appearance showed a smooth internal surface with increasing tissue formation. Histology at 169 days demonstrated a near-complete resorption of the polymer and formation of organized and functional tissue. Biochemical assays revealed increasing cellular and extracellular matrix contents. The control patch showed a slight bulging, indicating a beginning dilatation. CONCLUSION: This experiment showed that poly-4-hydroxybutyric acid is a feasible patch material in the pulmonary circulation.

Absorbable Implants↗
PubMed2000

Fabrication of a trileaflet heart valve scaffold from a polyhydroxyalkanoate biopolyester for use in tissue engineering.

Previously, we reported the implantation of a single tissue engineered leaflet in the posterior position of the pulmonary valve in a lamb model. The major problems with this leaflet replacement were the scaffold's inherent stiffness, thickness, and nonpliability. We have now created a scaffold for a trileaflet heart valve using a thermoplastic polyester. In this experiment, we show the suitability of this material in the production of a biodegradable, biocompatible scaffold for tissue engineered heart valves. A heart valve scaffold was constructed from a thermoplastic elastomer. The elastomer belongs to a class of biodegradable, biocompatible polyesters known as polyhydroxyalkanoates (PHAs) and is produced by fermentation (Metabolix Inc., Cambridge, MA). It was modified by a salt leaching technique to create a porous, three-dimensional structure, suitable for tissue engineering. The trileaflet heart valve scaffold consisted of a cylindrical stent (1 mm X 15 mm X 20 mm I.D.) containing three valve leaflets. The leaflets were formed from a single piece of PHA (0.3 mm thick), and were attached to the outside of the stent by thermal processing techniques, which required no suturing. After fabrication, the heart valve construct was allowed to crystallize (4 degrees C for 24 h), and salt particles were leached into doubly distilled water over a period of 5 days to yield pore sizes ranging from 80 to 200 microns. Ten heart valve scaffolds were fabricated and seeded with vascular cells from an ovine carotid artery. After 4 days of incubation, the constructs were examined by scanning electron microscopy. The heart valve scaffold was tested in a pulsatile flow bioreactor and it was noted that the leaflets opened and closed. Cells attached to the polymer and formed a confluent layer after incubation. One advantage of this material is the ability to mold a complete trileaflet heart valve scaffold without the need for suturing leaflets to the conduit. Second advantage is the use of only one polymer material (PHA) as opposed to hybridized polymer scaffolds. Furthermore, the mechanical properties of PHA, such as elasticity and mechanical strength, exceed those of the previously utilized material. This experiment shows that PHAs can be used to fabricate a three-dimensional, biodegradable heart valve scaffold.

Animals↗
PubMed2000

Measuring the "managedness" and covered benefits of health plans.

STUDY AIMS: (1) To develop indexes measuring the degree of managedness and the covered benefits of health insurance plans, (2) to describe the variation in these indexes among plans in one health insurance market, (3) to assess the validity of the health plan indexes, and (4) to examine the association between patient characteristics and the health plan indexes. Measures of the "managedness" and covered benefits of health plans are requisite for studying the effects of managed care on clinical practice and health system performance, and they may improve people's understanding of our complex health care system. DATA SOURCES/STUDY SETTING: As part of our larger Physician Referral Study, we collected health insurance information for 189 insurance product lines and 755 products in the Seattle, Washington metropolitan area, which we linked with the study's data for 2,277 patients recruited in local primary care offices. STUDY DESIGN: Managed care and benefit variables were constructed through content analysis of health plan information. Principal component analysis of the variables produced a managedness index, an in-network benefits index, and an out-of-network benefits index. Bivariable analyses examined associations between patient characteristics and the three indexes. PRINCIPAL FINDINGS: From the managed care variables, we constructed three provider-oriented indexes for the financial, utilization management, and network domains of health plans. From these, we constructed a single managedness index, which correlated as expected with the individual measures, with the domain indexes, with plan type (FFS, PPO, POS, HMO), with independent assessments of local experts, and with patients' attitudes about their health insurance. For benefits, we constructed an in-network benefits index and an out-of-network benefits index, which were correlated with the managedness index. The personal characteristics of study patients were associated with the managed care and benefit indexes. Study patients in more managed plans reported somewhat better health than patients in less managed plans. CONCLUSIONS: Indexes of the managedness and benefits of health plans can be constructed from publicly available information. The managedness and benefit indexes are associated with the personal characteristics and health status of study patients. Potential uses of the managed care and benefits indexes are discussed.

Abstracting and Indexing↗
PubMed1999

The expression of proinflammatory cytokine mRNA in the sciatic-tibial nerve of ischemia-reperfusion injury.

We evaluated the proinflammatory cytokines, TNF-alpha and IL-1beta, mRNA expression in the rat sciatic and tibial nerves following ischemia-reperfusion (IR) injury, using competitive RT-PCR, to explore the role of cytokines in IR injury. The expressions of both TNF-alpha and IL-1beta mRNA were related to severity of ischemia and occurred with reperfusion rather than ischemia alone. TNF-alpha gene expression peaked at 24 h of reperfusion, while that of IL-1beta peaked at 12 h. These data support the notion that the proinflammatory cytokines TNF-alpha and IL-1beta are involved in the inflammatory response of IR injury to the peripheral nervous system and may be involved in the pathophysiology of ischemic fiber degeneration.

Animals↗
PubMed1999

Solid state NMR studies of hydrogen bonding in a citrate synthase inhibitor complex.

The ionization state and hydrogen bonding environment of the transition state analogue (TSA) inhibitor, carboxymethyldethia coenzyme A (CMX), bound to citrate synthase have been investigated using solid state NMR. This enzyme-inhibitor complex has been studied in connection with the postulated contribution of short hydrogen bonds to binding energies and enzyme catalysis: the X-ray crystal structure of this complex revealed an unusually short hydrogen bond between the carboxylate group of the inhibitor and an aspartic acid side chain [Usher et al. (1994) Biochemistry 33, 7753-7759]. To further investigate the nature of this short hydrogen bond, low spinning speed 13C NMR spectra of the CMX-citrate synthase complex were obtained under a variety of sample conditions. Tensor values describing the chemical shift anisotropy of the carboxyl groups of the inhibitor were obtained by simulating MAS spectra (233 +/- 4, 206 +/- 5, and 105 +/- 2 ppm vs TMS). Comparison of these values with our previously reported database and ab initio calculations of carbon shift tensor values clearly indicates that the carboxyl is deprotonated. New data from model compounds suggest that hydrogen bonds in a syn arrangement with respect to the carboxylate group have a pronounced effect upon the shift tensors for the carboxylate, while anti hydrogen bonds, regardless of their length, apparently do not perturb the shift tensors of the carboxyl group. Thus the tensor values for the enzyme-inhibitor complex could be consistent with either a very long syn hydrogen bond or an anti hydrogen bond; the latter would agree very well with previous crystallographic results. Two-dimensional 1H-13C heteronuclear correlation spectra of the enzyme-inhibitor complex were obtained. Strong cross-peaks were observed from the carboxyl carbon to proton(s) with chemical shift(s) of 22 +/- 5 ppm. Both the proton chemical shift and the intensity of the cross-peak indicate a very short hydrogen bond to the carboxyl group of the inhibitor, the C.H distance based upon the cross-peak intensity being 2.0 +/- 0.4 A. This proton resonance is assigned to Hdelta2 of Asp 375, on the basis of comparison with crystal structures and the fact that this cross-peak was absent in the heteronuclear correlation spectrum of the inhibitor-D375G mutant enzyme complex. In summary, our NMR studies support the suggestion that a very short hydrogen bond is formed between the TSA and the Asp carboxylate.

Acyl Coenzyme A↗
PubMed1999

Remote-rendered 3D CT angiography (3DCTA) as an intraoperative aid in cerebrovascular neurosurgery.

OBJECTIVE: To assess the viability and utility of network-based rendering in the treatment of patients with cerebral aneurysms, we implemented an intraoperative rendering system and protocol using both three-dimensional CT angiography (3DCTA) and perspective volume rendering (PVR). MATERIALS AND METHODS: A Silicon Graphics InfiniteReality engine was connected via a Fast Ethernet network to a workstation in the neurosurgical operating room. A protocol was developed to isolate bone and vessels using an appropriate transfer function. Three-dimensional CT angiogram images were volume rendered and transmitted to the workstation using a bandwidth-conserving remote rendering system, and were rotated, cut using clipping planes, and viewed using normal and perspective views. Twelve patients with intracranial aneurysms were examined at surgery using this system. RESULTS: Rendering performance at optimal operating bandwidths (50-60 Mb/s) was excellent, with regeneration of a high-resolution image in less than 1 s. Network performance varied in two cases, slowing image regeneration. Surgeons found the images to be useful as an adjunct to conventional imaging in understanding the morphology of complex aneurysms and their relationship to the skull base. CONCLUSIONS: Intraoperative volume rendering using 3DCTA is achievable over a network, can reduce hardware costs by amortizing hardware among multiple users, and provides useful imaging information during the surgical treatment of cerebral aneurysms. Future operating suites may incorporate network-transmitted three-dimensional images as additional sources of imaging information.

Aged↗
PubMed1999

Musculoskeletal function assessment: reference values for patient and non-patient samples.

Although researchers and clinicians are encouraged to use health-status questionnaires to evaluate, monitor, and modify care, their use is hindered by the lack of reference values. Without reference values, it is difficult to interpret or evaluate questionnaire scores. In this paper, we present reference values for the Musculoskeletal Function Assessment, a 101-item health-status questionnaire designed and validated for patients with a broad range of musculoskeletal disorders. We describe reference values for two samples: non-patients (n = 123) and patients with isolated extremity injuries (n = 274). For the non-patient sample, descriptive statistics are presented by age and gender, measured at one point in time. For the patient sample, descriptive statistics are provided for seven Orthopaedic Trauma Association/AO diagnostic groups, measured at two points in time. Reference values for changes in the Musculoskeletal Function Assessment total score are described for patients 3 and 9 months and 6 and 12 months after injury. The total scores by post-injury interval, across the diagnostic groups, are significantly better at follow-up than at baseline (p = 0.00). Reference values for changes in total scores are also described in terms of these diagnostic groups across post-injury intervals. Musculoskeletal Function Assessment total scores for Orthopaedic Trauma Association/AO diagnostic groups are significantly better at follow-up than at baseline (p < 0.03). Changes in the total score are also tested for responsiveness with use of standardized response means. Large effects are demonstrated for patients completing the Musculoskeletal Function Assessment at 3 and 9 months (1.03), and small effects are demonstrated for those completing it at 6 and 12 months (0.49). Moderate and large effects are demonstrated for Orthopaedic Trauma Association/AO diagnostic groups across post-injury intervals.

Adolescent↗
PubMed1999

Treatment of cavernous sinus tumors with linear accelerator radiosurgery.

Since 1989, 79 patients with benign or malignant cavernous sinus tumors, have been treated at Stanford University with linear accelerator (linac) radiosurgery. Radiosurgery has been used as (1) a planned second-stage procedure for residual tumor following surgery, (2) primary treatment for patients whose medical conditions preclude surgery, (3) palliation of malignant lesions, and (4) definitive treatment for small, well-localized, poorly accessible tumors. Mean patient age was 52 years (range, 18 to 88); there were 28 males and 51 females. Sixty-one patients had benign tumors; 18 had malignant tumors. Mean tumor volume was 6.8 cm(3) (range 0.5 to 22.5 cm(3)) covered with an average of 2.3 isocenter (range, 1 to 5). Radiation dose averaged 17.1 Gy. Mean follow-up was 46 months. Tumor control or shrinkage, or both, varied with pathology. Radiographic tumor improvement was most pronounced in malignant lesions, with greater than 85% showing reduction in tumor size; benign tumors (meningiomas and schwannomas) had a 63% control rate and 37% shrinkage rate, with none enlarging. We concluded that stereotactic radiosurgery is a valuable tool in managing cavernous sinus tumors. There was excellent control and stabilization of benign tumors and palliation of malignant lesions.

Journal Article↗