Risk of uterine rupture during labor among women with a prior cesarean delivery

BACKGROUND

Each year in the United States, approximately 60 percent of women with a prior cesarean delivery who become pregnant again attempt labor. Concern persists that a trial of labor may increase the risk of uterine rupture, an uncommon but serious obstetrical complication.

METHODS

We conducted a population-based, retrospective cohort analysis using data from all primiparous women who gave birth to live singleton infants by cesarean section in civilian hospitals in Washington State from 1987 through 1996 and who delivered a second singleton child during the same period (a total of 20,095 women). We assessed the risk of uterine rupture for deliveries with spontaneous onset of labor, those with labor induced by prostaglandins, and those in which labor was induced by other means; these three groups of deliveries were compared with repeated cesarean delivery without labor.

RESULTS

Uterine rupture occurred at a rate of 1.6 per 1000 among women with repeated cesarean delivery without labor (11 women), 5.2 per 1000 among women with spontaneous onset of labor (56 women), 7.7 per 1000 among women whose labor was induced without prostaglandins (15 women), and 24.5 per 1000 among women with prostaglandin-induced labor (9 women). As compared with the risk in women with repeated cesarean delivery without labor, uterine rupture was more likely among women with spontaneous onset of labor (relative risk, 3.3; 95 percent confidence interval, 1.8 to 6.0), induction of labor without prostaglandins (relative risk, 4.9; 95 percent confidence interval, 2.4 to 9.7), and induction with prostaglandins (relative risk, 15.6; 95 percent confidence interval, 8.1 to 30.0).

CONCLUSIONS

For women with one prior cesarean delivery, the risk of uterine rupture is higher among those whose labor is induced than among those with repeated cesarean delivery without labor. Labor induced with a prostaglandin confers the highest risk.

Delivery method and self-reported postpartum general health status among primiparous women

Despite nearly four million deliveries in the United States each year, minimal information exists on unintended health consequences following childbirth, particularly in relation to delivery method. The purpose of this study was to assess the association between method of delivery and the general health status, sexual, bowel and urinary functioning of primiparous women as measured at 7 weeks postpartum. Data from the Statewide Obstetrical Review of Quality System (StORQS) Survey of Maternity Care in Washington State were analysed. Participants included all primiparous women with a delivery of a singleton infant discharged alive between August and December 1991 from 10 non-federal short-stay hospitals who responded to the StORQS Survey of Maternity Care (n = 971). The main outcome measures included the modified Medical Outcomes Study 36-Item Short-Form Health Survey and self-reported sexual, bowel and urinary functioning. At 7 weeks postpartum, women who had caesarean or assisted vaginal deliveries reported significantly lower postpartum general health status scores than women with unassisted vaginal delivery. Additionally, women with assisted vaginal delivery reported significantly worse sexual, bowel and urinary functioning. Our results suggest that more careful attention to the postpartum general health and sexual functioning of women with caesarean and assisted vaginal delivery may be merited.

Pro- and Anti-inflammatory Cytokine Gene Expression in Rat Sciatic Nerve Chronic Constriction Injury Model of Neuropathic Pain

Cytokines may be pathophysiologically involved in hyperalgesia. Uncertainty exists about the types of cytokines and their site of action. To study the role of key pro- and anti-inflammatory cytokines in a chronic constriction model of neuropathic pain, mRNA expression of TNF, IL-1beta, IL-6, and IL-10 was quantified using competitive RT-PCR. Each cytokine mRNA in rat sciatic nerve was examined at days 3, 7, 14, and 45 after chronic constriction injury (CCI). We also undertook behavioral testing of these rats. Thermal warming and touch thresholds were significantly reduced at days 3, 7, and 14 in the CCI group, compared with the sham-operated group. Cytokine gene expression in sciatic nerve was significantly increased at day 7 for IL-1beta and IL-6 and at day 14 for TNF. Expression of IL-10 underwent a gradual and progressive increase, reaching statistical significance at day 45.

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.

Analysis of the diversity of African streak mastreviruses using PCR-generated RFLPs and partial sequence data

Maize streak virus (MSV) is the most economically significant member of a diverse group of African grass-infecting Mastrevirus species in the family Geminiviridae. We designed a single set of degenerate primers which enables the PCR amplification of an approximately 1300 bp DNA fragment spanning both conserved (the RepA gene) and variable (the long intergenic region and MP gene) portions of these viruses' genomes. Using restriction fragment length polymorphism (RFLP) analysis of PCR products obtained from 39 MSV, one SSV, and two PanSV isolates, it was possible to both identify the different virus species, which differ in nucleotide sequence by up to 40%, and to differentiate between MSV isolates sharing up to 99% sequence identity. The reliability of the RFLP data for typing the MSV isolates was verified by the phylogenetic analysis of the partial genomic nucleotide sequences of a representative subset of the MSV isolates. Based on both the RFLP and sequence data, the MSV isolates could be clearly differentiated into the four groups: these were a group of predominantly maize-infecting isolates, and three groups containing grass/wheat-infecting isolates. RFLP analysis also revealed a number of mixed virus infections in which, in certain instances, it was possible to identify individual population members.

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.

Stereotactic radiosurgery and hypofractionated stereotactic radiotherapy for residual or recurrent cranial base and cervical chordomas

Object

In patients with chordomas the lesions often recur. Furthermore, the location of some chordomas within the base of the skull and the cervical spine can prevent complete resection from being achieved. Previous series have shown that stereotactic radiosurgery can be used as a treatment for residual chordomas with good overall results. The authors review their experience in using linear accelerator (LINAC) stereotactic radiosurgery to treat patients with recurrent and/or residual cranial base and cervical chordomas.

Methods

Ten patients with chordomas (eight with cranial base and two with cervical lesions [below C-2]) underwent LINAC stereotactic radiosurgery. The mean patient age was 49 years (range 30–73 years). There were seven men and three women. Three patients had undergone one prior surgery, five had undergone two previous surgeries, and two had undergone three prior operations. The mean radiation dose was 19.4 Gy (range 18–24 Gy), and the maximum intratumoral dose averaged 27 Gy (range 24.1–33.1 Gy). The mean secondary collimator size was 14.4 mm (range 7.5–20 mm). The volume of the tumor treated ranged from 1.1 to 21.5 ml. In five patients a standard frame-based LINAC radiosurgery system was used, whereas in the other five the CyberKnife, a frameless image-guided LINAC radiosurgical system, was used. All patients were available for follow-up review, which averaged 4 years (range 1–9 years). Over the course of follow up, one chordoma (10%) was smaller in size, seven were stable, and two chordomas progressed (one in a patient who underwent reoperation and a second course of stereotactic radiosurgery, and the second in a patient who underwent reoperation alone). There were no new neurological deficits noted following radiosurgery in the eight of 10 patients in whom there was no tumor progression, and no patient developed radiation-induced necrosis.

Conclusions

Stereotactic radiosurgery can be used to treat patients with recurrent or residual chordomas with excellent tumor control rates. Longer follow-up review in larger series is warranted to confirm these findings.

Cesarean delivery and postpartum mortality among primiparas in Washington State, 1987-1996(1)

OBJECTIVE

To examine the association between delivery method and mortality within 6 months of delivery among primiparas.

METHODS

We conducted a population-based, retrospective cohort analysis using statewide, maternally linked birth certificate, hospital discharge, and death certificate data. The present cohort was all primiparas who gave birth to live-born infants in civilian hospitals in Washington State from January 1, 1987 through December 31, 1996 (n = 265,471). Odd ratios (OR) and 95% confidence intervals (CI) were calculated for overall mortality, pregnancy-related mortality, and pregnancy-unrelated mortality associated with delivery method.

RESULTS

Thirty-two women (12.1 per 100,000 singleton live births) died within 6 months of delivery of their first child. Eleven of 32 deaths were pregnancy related (4.1 per 100,000 singleton live births, 95% CI 1.6, 6.5), and 21 of the 32 deaths were not pregnancy related (7.9 per 100,000 singleton live births, 95% CI 4.5, 11.3). The pregnancy-related mortality rate was higher among women delivered by cesarean (10.3/100,000) than among women delivered vaginally (2.4/100,000). In logistic regression analyses, women who had cesarean delivery were not at significantly higher risk of death overall after adjustment for maternal age (OR 1.7, 95% CI 0.3, 3.6), pregnancy-related death after adjustment for maternal age and severe preeclampsia (OR 2.2, 95% CI 0.6, 7.9), or pregnancy-unrelated death after adjustment for maternal age and marital status (OR 0.9, 95% CI 0.3, 2.7), relative to women who had vaginal delivery.

CONCLUSION

Cesarean delivery might be a marker for serious preexisting morbidities associated with increased mortality risk rather than a risk factor for death in and of itself. Data from additional sources such as medical records and autopsy reports are necessary to disentangle preexisting mortality risk from risk associated solely with delivery method.

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%.

Evaluation of a command-line parser-based order entry pathway for the Department of Veterans Affairs electronic patient record

OBJECTIVE

To improve and simplify electronic order entry in an existing electronic patient record, the authors developed an alternative system for entering orders, which is based on a command- interface using robust and simple natural-language techniques.

DESIGN

The authors conducted a randomized evaluation of the new entry pathway, measuring time to complete a standard set of orders, and users' satisfaction measured by questionnaire. A group of 16 physician volunteers from the staff of the Department of Veterans Affairs Puget Sound Health Care System-Seattle Division participated in the evaluation.

RESULTS

Thirteen of the 16 physicians (81%) were able to enter medical orders more quickly using the natural-language-based entry system than the standard graphical user interface that uses menus and dialogs (mean time spared, 16.06 +/- 4.52 minutes; P=0.029). Compared with the graphical user interface, the command--based pathway was perceived as easier to learn (P<0.01), was considered easier to use and faster (P<0.01), and was rated better overall (P<0.05).

CONCLUSION

Physicians found the command- interface easier to learn and faster to use than the usual menu-driven system. The major advantage of the system is that it combines an intuitive graphical user interface with the power and speed of a natural-language analyzer.

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.

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.

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.

Improved Efficiency of Zea mays Agroinoculation with Maize streak virus

Agroinoculation is a technique permitting the transmission of geminivirus genomes cloned in Agrobacterium tumefaciens into a wide variety of mono- and dicotyledonous host plants. Most geminiviruses are obligately transmitted by insect vector species under natural conditions; therefore, agroinoculation has greatly simplified the study of this group of viruses. In many cases, agroinoculation has replaced insect transmission, and has been used to compare virulence characteristics among viruses. Here we report on the discovery that, in agroinfectious Maize streak virus constructs, the orientation of cloned viral genomes relative to the Cauliflower mosaic virus 35S (CaMV35S) promoter of the binary cloning vector pBI121 can significantly affect agroinfectivity of the constructs. Rates at which plants became symptomatic were significantly higher when agroinoculating maize seedlings with constructs containing the CaMV35S promoter upstream of the viral replication-associated protein (Rep) gene than when the same viruses were cloned either in the opposite orientation or into a vector without a strong eukaryotic promoter sequence. Plants infected using the construct with Rep cloned downstream of the CaMV35S promoter also displayed more stunting and, in the early stages of the infection, more severe chlorotic streak symptoms.

Treatment of nasopharyngeal carcinoma: stereotactic radiosurgical boost following fractionated radiotherapy

Treatment of patients with nasopharyngeal carcinoma (NPC) using external beam radiation therapy (XRT) alone results in significant local recurrence. To improve local control, stereotactic radiosurgery (SRS) was used to boost radiation to the primary tumor site following XRT in 23 patients with NPC. SRS was delivered utilizing a frame-based linear accelerator as a boost (range 7-15 Gy, median 12 Gy) following XRT (range 64.8- 70 Gy, median 66 Gy). In all 23 patients (100%) receiving SRS following XRT local control was achieved at a mean follow-up of 21 months (range 2-64 months). There have been no complications of treatment caused by SRS. However, 8 patients (35%) have subsequently developed regional or distant metastases. SRS boost following XRT provides excellent local control in NPC and should be considered for patients with skull base involvement.

LINAC radiosurgery for cavernous sinus meningiomas

Radiosurgery is increasingly used to treat unresectable cavernous sinus tumors. Since 1989, 24 patients with cavernous sinus meningiomas have been treated at Stanford University Medical Center with linear accelerator (LINAC) radiosurgery. The mean age of the patients was 47.8 years (range 28-78). The mean volume treated was 6. 83 cm3 (range 0.45-22.45 cm3), covered with an average of 2.3 isocenters (range 1-5). Radiation dose averaged 17.7 Gy (range 14-20 Gy). This group of patients was retrospectively studied by sending clinical questionnaires to both the patient/family and referring physicians, and reviewing clinic charts. In addition, follow-up imaging studies were obtained to measure residual tumor volume. Follow-up averaged 45.6 months (range 19-80). Tumor control (stabilization) following radiosurgery was noted in 15 (63%) and tumor shrinkage in 9 (37%). Seven meningiomas (29%) showed evidence of central tumor necrosis on MRI imaging 1-3 years after radiosurgery. Neurologic status was improved in 10 patients (42%) and unchanged in 12 patients (50%). There was 1 case of symptomatic brain necrosis and 1 case of radiation edema (asymptomatic). All other complications were transient, including 4 cases of trigeminal hypesthesia and 1 case of worsening diplopia. The 2-year actuarial tumor control rate was 100%. Although follow-up is still short, this experience corroborates prior reports that radiosurgery can be used to treat selected small cavernous sinus meningiomas with good to excellent clinical results and minimal morbidity.

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.

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.

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.

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.

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.

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.

Evaluation of biodegradable, three-dimensional matrices for tissue engineering of heart valves

A crucial factor in tissue engineering of heart valves is the type of scaffold material. In the following study, we tested three different biodegradable scaffold materials, polyglycolic acid (PGA), polyhydroxyalkanoate (PHA), and poly-4-hydroxybutyrate (P4HB), as scaffolds for tissue engineering of heart valves. We modified PHA and P4HB by a salt leaching technique to create a porous matrix. We constructed trileaflet heart valve scaffolds from each polymer and tested them in a pulsatile flow bioreactor. In addition, we evaluated the cell attachment to our polymers by creating four tubes of each material (length equals 4 cm; inner diameter, 0.5 cm), seeding each sample with 8,000,000 ovine vascular cells, and incubating the cell-polymer construct for 8 days (37 degrees C and 5% CO2). The seeded vascular constructs were exposed to continuous flow for 1 hour. Analysis of samples included DNA assay before and after flow exposure, 4-hydroxyproline assay, and environmental scanning electron microscopy (ESEM). We fabricated trileaflet heart valve scaffolds from porous PHA and porous P4HB, which opened and closed synchronously in a pulsatile bioreactor. It was not possible to create a functional trileaflet heart valve scaffold from PGA. After seeding and incubating the PGA-, PHA-, and P4HB-tubes, there were significantly (p < 0.001) more cells on PGA compared with PHA and P4HB. There were no significant differences among the materials after flow exposure, but there was a significantly higher collagen content (p < 0.017) on the PGA samples compared with P4HB and PHA. Cell attachment and collagen content was significantly higher on PGA samples compared with PHA and P4HB. However, PHA and P4HB also demonstrate a considerable amount of cell attachment and collagen development and share the major advantage that both materials are thermoplastic, making it possible to mold them into the shape of a functional scaffold for tissue engineering of heart valves.

Fractionated stereotactic radiosurgery and preservation of hearing in patients with vestibular schwannoma: a preliminary report

OBJECTIVE

Microsurgery and stereotactic radiosurgery (SRS) for vestibular schwannomas are associated with a relatively high incidence of sensorineural hearing loss. A prospective trial of fractionated SRS was undertaken in an attempt to preserve hearing and minimize incidental cranial nerve injury.

METHODS

Thirty-three patients with vestibular schwannomas were treated with 2100 cGy in three fractions during a 24-hour period using conventional frame-based linear accelerator radiosurgery. The median tumor diameter was 20 mm (range, 7-42 mm). Baseline and follow-up evaluations included audiometry and contrast-enhanced magnetic resonance imaging. End points were tumor progression, preservation of serviceable hearing, and treatment-related complications.

RESULTS

Thirty-one patients (32 tumors) were assessable for tumor progression and treatment-related complications and 21 patients for preservation of serviceable hearing, with a median follow-up interval of 2 years (range, 0.5-4.0 yr). Tumor regression or stabilization was documented in 30 patients (97%) and tumor progression in 1 (3%). The patient with tumor progression remains asymptomatic and has not required surgical intervention. Five patients (16%) developed trigeminal nerve injury at a median of 6 months (range, 4-12 mo) after SRS; two of these patients had preexisting trigeminal neuropathy. One patient (3%) developed facial nerve injury (House-Brackmann Class 3) 7 months after SRS. Preservation of useful hearing (Gardner-Robertson Class 1-2) was 77% at 2 years. All patients with pretreatment Gardner-Robertson Class 1 to 2 hearing maintained serviceable (Class 1-3) hearing as of their last follow-up examination.

CONCLUSION

Three-fraction SRS with a conventional stereotactic frame is feasible and well tolerated in the treatment of acoustic neuroma. This study demonstrates a high rate of hearing preservation and few treatment-related complications among a relatively high-risk patient cohort (tumors >15 mm or neurofibromatosis Type 2). Longer follow-up will be required to assess the durability of tumor control.

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.

Short musculoskeletal function assessment questionnaire: validity, reliability, and responsiveness

BACKGROUND

A short questionnaire on functional status was designed for use in community-based outcome studies and in the management of individual patients who have musculoskeletal disease. As most musculoskeletal care is delivered in community practices, short, validated instruments are necessary to perform clinical studies on the effectiveness of treatment in this setting.

METHODS

A forty-six-item questionnaire was created as an extension of the work to develop the longer, 101-item Musculoskeletal Function Assessment (MFA) questionnaire. The Short Musculoskeletal Function Assessment (SMFA) questionnaire consists of the dysfunction index, which has thirty-four items for the assessment of patient function, and the bother index, which has twelve items for the assessment of how much patients are bothered by functional problems. The SMFA questionnaire was evaluated for reliability, validity, and responsiveness in a population of 420 patients who had a musculoskeletal disease or injury.

RESULTS

The SMFA questionnaire demonstrated excellent internal consistency and stability, with most values greater than 0.90. Content validity for the dysfunction and bother indexes was supported with very little skew (less than 1.00), few ceiling effects (less than 5 percent), and no floor effects. Convergent validity was supported with significant correlations between the SMFA dysfunction and bother indexes and the physicians' ratings of patient function (for example, activities of daily living, recreational and leisure activities, and emotional function [rho > or = 0.40]) and standard clinical measures (for example, grip strength and walking speed [r > or = 0.401). Convergent and discriminant construct validity of the SMFA indexes were demonstrated (p < 0.01) in comparisons with clinical, demographic, Short Form-36 (SF-36), and life-change data. The responsiveness of the SMFA questionnaire to change over time was demonstrated with standardized response means ranging from moderate (0.76) to large (-1.14) for patients who had changes in health status.

CONCLUSIONS

The SMFA questionnaire may be used for clinical assessments of the impact of treatment in groups of patients who have musculoskeletal disease or injury. It also may be used in clinical settings to provide reliable and valid assessments of the health status of an individual patient.

Evaluation of Maize Streak Virus Pathogenicity in Differentially Resistant Zea mays Genotypes

ABSTRACT We devised a rapid technique for the objective and precise assessment of both the pathogenicity of maize streak virus (MSV) isolates and the MSV resistance of maize genotypes. The technique involves the use of agroinoculation to infect maize seedlings and the objective symptom evaluation by quantification of infection rates, stunting, and chlorotic leaf areas. In assessing the MSV resistance of 19 maize genotypes, we describe how the use of differentially virulent virus isolates enables the analysis of MSV resistance phenotypes, ranging from extremely susceptible to completely immune. We further demonstrate how quantification of chlorotic leaf areas by image analysis permits differentiation between degrees of MSV resistance that are indistinguishable from one another using currently employed symptom assessment approaches. Using chlorotic area measurements, we quantify the virulence of a diverse group of 10 MSV isolates and, through agroinoculation of differentially susceptible maize genotypes, we demonstrate the use of our technique in evaluating the pathogenicity of these isolates.

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.

PHA applications: addressing the price performance issue: I. Tissue engineering

This paper describes the development of medical applications for polyhydroxyalkanoates (PHAs), a class of natural polymers with a wide range of thermoplastic properties. Methods are described for preparing PHAs with high purity, modifying these materials to change their surface and degradation properties, and methods for fabricating them into different forms, including tissue engineering scaffolds. Preliminary reports characterizing their in vivo behavior are given, as well as methods for using the natural polymers in tissue engineering applications.

The Planetree Model Hospital Project: an example of the patient as partner

The Planetree Model Hospital Project at Pacific Presbyterian Medical Center in San Francisco uses a patient-centered philosophy to incorporate the patient as a partner in the care process. This article describes the Planetree unit and discusses two aspects of the program--training patients to be partners and increasing nurse satisfaction. Such programs have the potential for improving the health outcomes of patients and aiding hospitals by assuring quality of care with greater patient participation, by improving public relations, and by promoting staff satisfaction.

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.

Mortality, health services use, and health behavior in a cohort of well older adults

OBJECTIVES

To construct an evidence-based Good Health Behavior Score and examine the relationship between aggregate health behaviors, mortality, and health services utilization in the last year of life in a cohort of well older adults.

DESIGN

A prospective cohort.

SETTING

A large health maintenance organization.

PARTICIPANTS

1867 older enrollees who responded to a health promotion survey.

MEASUREMENTS

A baseline self-administered questionnaire was used to ascertain health behaviors in 1987-1988, and vital status was determined 48 months later. A Good Health Behavior Score was calculated, and a Cox proportional hazards model was used to compare high, middle, and low score groups regarding risk of death. For those who died, differences in amount and type of health services utilization in relation to the summary score were compared for the year before death.

RESULTS

During the 4 years of follow-up, the mortality rate for the mid-level score group was 50% less, and in the highest score group was 70% less, than in the lowest score group. Among decedents, no significant differences were found between high and low Good Health Behavior score groups for inpatient and outpatient utilization, pharmacy use, or total cost during the last year of life.

CONCLUSION

An easily developed and simple health behavior score can predict short term mortality quite strongly. Medical care costs in the last year of life were similar in individuals with higher and lower health behavior scores.

State-sponsored programs for the uninsured: is there adverse selection?

Risk contracting by states for coverage of previously uninsured populations has been hampered by uncertainty regarding likely claims experience. This study reports on the utilization experience of two state programs offering subsidized coverage in commercial managed care organizations to low-income and previously uninsured people. Program participants used services similarly to people enrolled through large employer benefit plans. There was no evidence of pent-up demand or an unusual level of chronic illness. Similarly, there was little evidence of underutilization, although dissatisfaction and reported barriers to service were more frequent among nonwhite enrollees.

Health consequences of pregnancy and childbirth as perceived by women and clinicians

OBJECTIVE

To develop patient-centered outcome measures for clinical research by characterizing the effects of pregnancy and childbirth on functioning.

METHODS

Five focus groups of mothers (n = 33) and three focus groups of clinicians (midwives [n = 8], obstetricians [n = 4], and family practitioners [n = 7]) were convened. Discussions were audiotaped and transcribed. Major narrative themes were identified by using two independent readers and were confirmed by participants and additional clinicians.

RESULTS

Themes were grouped into four outcome domains: physical, psychologic, sexual, and social. Themes identified included lack of knowledge about postpartum health, emotional lability, sexual satisfaction, depression, parenting skills, body image, fatigue, and incontinence. Lack of knowledge about typical postpartum health was the dominant theme for mothers and clinicians. Mothers felt unprepared for the health consequences of pregnancy and delivery. Clinicians lamented that paucity of data made counseling and treating patients difficult. Decreased functioning months after delivery was reported. Differences between mother and clinician concerns surfaced, particularly in emphasis. Mothers wanted more information about their health; providers emphasized newborn care. Mothers reported inspiration to improve their economic circumstances; clinicians emphasized improving maternal health. Mothers wanted control during labor, whereas clinicians believed control was not always possible.

CONCLUSION

Women often felt poorly prepared for the postpartum period in part because functional health consequences are not well understood. This study suggests maternal functional health may be decreased for months after delivery, even among uncomplicated patients. This study identified new maternal outcome measures, which are being incorporated into an outcomes questionnaire.

Clinical experience with image-guided robotic radiosurgery (the Cyberknife) in the treatment of brain and spinal cord tumors

The Cyberknife is an image-guided "frameless" dedicated radiosurgical device. This instrument has several distinct advantages over frame-based systems, including improved patient comfort, increased treatment degrees of freedom, and the potential to target extracranial lesions. Clinical results thus far with respect to the treatment of malignant intracranial tumors has been promising. Additionally, the Cyberknife will likely revolutionize the application of radiosurgery to extracranial sites. A description of the components, treatment planning, and clinical results of the Cyberknife will be reviewed.

Acute hearing loss following fractionated stereotactic radiosurgery for acoustic neuroma. Report of two cases

Two cases of acute hearing loss are reported following fractionated stereotactic radiosurgery for acoustic neuroma. Both patients had neurofibromatosis type 2 and were treated with a peripheral tumor dose of 21 Gy delivered in three fractions (7 Gy each) with a minimum interfraction interval of 10 hours. One patient who had previously undergone surgical resection of the treated tumor presented with only rudimentary hearing in the treated ear secondary to an abrupt decrease in hearing prior to treatment. That patient reported total loss of hearing before complete delivery of the third fraction. The second patient had moderately impaired hearing prior to treatment; however, within 10 hours after delivery of the final fraction, he lost all hearing. Both patients showed no improvement in response to glucocorticoid therapy. Possible explanations for this phenomenon are presented.

Stereotactic radiosurgery of angiographically occult vascular malformations: 14-year experience

OBJECTIVE

Radiosurgery is generally effective in obliterating true arteriovenous malformations, but less is known about its effects on angiographically occult vascular malformations (AOVMs). Since July 1983, 57 patients with surgically inaccessible AOVMs of the brain were treated using helium ion (47 patients) or linear accelerator (10 patients) radiosurgery. This study retrospectively evaluates the response of these AOVMs to treatment.

METHODS

All patients presented with previous hemorrhage. The mean patient age was 35.6 years (range, 13-71 yr). The mean AOVM volume was 2.25 cm3 (range, 0.080-15.2 cm3), treated with a mean of 18.0 Gy equivalent (physical dose x relative biological effectiveness, which is 1.3 for helium ion Bragg peak) (range, 7.0-40 Gy equivalent). The Drake scale scores before treatment were as follows: excellent (25 patients), good (26 patients), and poor (6 patients). The mean follow-up period was 7.5 years (range, 9 mo-13.8 yr).

RESULTS

Eighteen patients (32%) bled symptomatically (20 hemorrhages) after radiosurgery. Sixteen hemorrhages occurred within 36 months after radiosurgery (9.4% annual bleed rate; 16 hemorrhages/171 patient yr); 4 hemorrhages occurred more than 36 months after treatment (1.6% annual bleed rate; 4 hemorrhages/257 patient yr) (P < 0.001). Complications included symptomatic radiation edema (four patients, 7%), necrosis (one patient, 2%), and increased seizure frequency (one patient, 2%). Eight patients underwent surgical resection of their AOVMs 8 to 59 months after radiosurgery because of subsequent hemorrhage. The Drake scale scores after treatment were as follows: excellent (25 patients), good (24 patients), poor (3 patients), and dead (5 patients, 3 of whom died as a result of causes unrelated to the AOVMs or radiosurgery).

CONCLUSION

Radiosurgery may be useful for AOVMs located in surgically inaccessible regions of the brain. A significant decrease in bleed rate exists more than 3 years after treatment compared with the bleed rate within 3 years of treatment. Because current neuroradiological techniques are not able to image obliterative response in these slow-flow vascular lesions, longer term clinical follow-up is required.

Treatment of hemangioblastomas in von Hippel-Lindau disease with linear accelerator-based radiosurgery

OBJECTIVE

Stereotactic radiosurgery is increasingly being used to treat hemangioblastomas, particularly those that are in surgically inaccessible locations or that are multiple, as is common in von Hippel-Lindau disease. The purpose of this study was to retrospectively evaluate the effectiveness of radiosurgery in the treatment of hemangioblastomas.

METHODS

From 1989 to 1996, 29 hemangioblastomas in 13 patients with von Hippel-Lindau disease were treated with linear accelerator-based radiosurgery. The mean patient age was 40 years (range, 31-57 yr). The radiation dose to the tumor periphery averaged 23.2 Gy (range, 18-40 Gy). The mean tumor volume was 1.6 cm3 (range, 0.07-65.4 cm3). Tumor response was evaluated in serial, contrast-enhanced, computed tomographic and magnetic resonance imaging scans. The mean follow-up period was 43 months (range, 11-84 mo).

RESULTS

Only one (3%) of the treated hemangioblastomas progressed. Five tumors (17%) disappeared, 16 (55%) regressed, and 7 (24%) remained unchanged in size. Five of nine patients with symptoms referable to treated hemangioblastomas experienced symptomatic improvement. During the follow-up period, one patient died as a result of progression of untreated hemangioblastomas in the cervical spine. Three patients developed radiation necrosis, two of whom were symptomatic.

CONCLUSION

Although follow-up monitoring is limited, stereotactic radiosurgery provides a high likelihood of local control of hemangioblastomas and is an attractive alternative to multiple surgical procedures for patients with von Hippel-Lindau disease.

Randomized trial of a patient-centered hospital unit

Patient-centered hospital units have grown out of the national trend to greater consumerism, but few of these units have been evaluated rigorously. We used a randomized controlled trial to compare patient outcomes on the Planetree Model Hospital Unit with other medical-surgical units in the hospital. Planetree patients were significantly more satisfied than controls with their hospital stay, the unit's environment and nursing care, but did not differ in ratings of physician care. Planetree patients reported more involvement in their care while hospitalized and higher satisfaction with the education they received. There were few differences between Planetree and controls in health behaviors. While Planetree patients reported better mental health status and role functioning after discharge, their health status was similar to controls after 3 to 6 months. There were no differences in length of stay and charges for the index hospitalization, readmissions or outpatient care during the following year.

Microcomputer-Based Quantification of Maize Streak Virus Symptoms in Zea mays

ABSTRACT We investigated the use of computer-assisted image analysis techniques for the objective quantification of maize streak virus (MSV) symptoms in Zea mays. We compared independent duplicate evaluations of chlorotic lesion areas occurring on MSV-infected leaves using visual assessment, a commercial image analysis system, and a custom image analysis system employing software developed in our laboratory. Relative to visual assessments of disease severity, computer-assisted image analysis employing both the commercial and custom systems provided significant enhancements in the accuracy and precision of chlorotic area estimations. The commercial image analysis system afforded no significant improvement in precision or accuracy over the custom system. An important advantage of examining images using the custom-written software was that the software permitted a high degree of analysis automation. Digitized images of maize leaves could be automatically analyzed by the custom software five times faster than, and with the same precision and accuracy as, when the same images were analyzed with the commercial software. Because of the flexibility of the image analysis techniques described, they should be applicable to the measurement of symptom severity in other plant host-pathogen combinations.

Comparison of length of stay for asthma by hospital type

OBJECTIVE

To determine whether length of stay (LOS) for asthma admissions at a local university-affiliated children's hospital (UACH) is similar to that of community hospitals within the same county.

METHODS

A retrospective analysis was performed using computerized hospital abstract records from 1989 through 1994. The study population was children 1 to 18 years old whose first or only hospitalization for a primary diagnosis of asthma occurred during the study period at either the UACH or one of the 17 community hospitals in King County, WA, that admit pediatric patients (n = 2491). Transfers and patients with chronic obstructive asthma or secondary diagnoses such as cystic fibrosis were not included in the study. Asthma patients were compared by sociodemographic and health risk characteristics such as age, sex, insurance status, and a comorbidity severity score. Differences between the two hospital populations were tested by chi2 and t tests. The effect of hospitalization at the UACH or the community hospitals on LOS was determined using analysis of covariance after adjusting for the sociodemographic and health risk covariates.

RESULTS

Sixty-two percent (62%) of the asthma patients in the study population were discharged from the UACH. Compared with patients discharged from the community hospitals, the UACH patients were significantly younger, more often male, used public insurance, and resided in areas with lower median household incomes. The severity of comorbidities was not different between the two hospital groups. Overall, adjusted mean LOS was not significantly longer at the UACH (2.1 days) than at the community hospitals (2.0 days); however, adjusted mean LOS for specific subgroups, most notably poor children and those with public insurance, was significantly longer at the UACH.

CONCLUSION

LOS for first or only asthma hospitalizations during 1989 through 1994 at the UACH was similar to local community hospitals within the same county. Specific subgroups of children were hospitalized for a longer period at the UACH, but children with private insurance and from areas with higher median household incomes had similar LOS, and presumably costs, at the UACH and the community hospitals.

A randomized controlled trial of CQI teams and academic detailing: can they alter compliance with guidelines?

BACKGROUND

The availability of clinical guidelines in isolation has generally failed to promote voluntary change in practice patterns. Accordingly, a randomized controlled trial was conducted to determine the effectiveness of academic detailing (AD) techniques and continuous quality improvement (CQI) teams in increasing compliance with national guidelines for the primary care of hypertension and depression.

METHODS

Fifteen small group practices at four Seattle primary care clinics were assigned to one of three study arms--AD alone, AD plus CQI teams, or usual care. The activity of 95 providers and 4,995 patients was monitored from August 1, 1993, through January 31, 1996. Twelve-month baseline and study periods were separated by a six-month "wash-in" period during which training sessions were held. Changes in hypertension prescribing, blood pressure control, depression recognition, use of older tricyclics, and scores on the Hopkins Symptom Checklist depression scale were examined.

RESULTS

Clinics varied considerably in their implementation of both the AD and the CQI team interventions. Across all sites, AD was associated with change in a single process measure, a decline in the percentage of depressives prescribed first-generation tricyclics (-4.7 percentage points versus control, p = 0.04). No intervention effects were demonstrated for CQI teams across all sites for either disease condition. Within the clinic independently judged most successful at implementing both change strategies, the use of CQI teams and AD in combination did increase the percentage of hypertensives adequately controlled (17.3 percentage points versus control, p = 0.03).

SUMMARY AND CONCLUSIONS

The AD techniques and the CQI teams evaluated were generally ineffective in improving guideline compliance and clinical outcomes regarding the primary care of hypertension and depression.

Assessing compliance to antihypertensive medications using computer-based pharmacy records

Systematic approaches for compliance problem detection and intervention are needed if the benefits of prescribed drug therapy in chronic disease management are to be optimized. As with all measures of compliance, computer algorithms based on refill patterns have advantages and disadvantages. They are unobtrusive and easily determined, but they measure the timeliness of prescription refills, not actual drug-taking. Computer-generated algorithms for assessing compliance based on refill patterns should be used by practitioners with caution, because they are not only markers for potential drug taking compliance problems, but also for discrepancies between the medical chart, pharmacy records and verbal advice given to the patient. Because patients may obtain refills before depleting their supply, compliance rates using this methodology are best determined across several refills. In particular, we urge caution in applying them over time periods of less than 60 days. Longer minimum time periods further decrease the likelihood of "false positives" but limit the number of patients for whom a compliance measure can be computed. For the health professional (eg, the pharmacist) responsible for monitoring drug-taking compliance of patients, the message seems clear: when reviewing computer-generated noncompliance "flags," the first task is to fully explore the possibility of discrepancies in drug records before initiating compliance-related interventions.

Correlates and effect of non-response in a postpartum survey of obstetrical care quality

This study investigated the differences between unprompted respondents, prompted respondents, and non-respondents to a postpartum postal survey, and determined the likely impact of non-response on the accuracy of calculations of patient assessments of obstetrical care quality. Birth certificate and hospital discharge data were obtained for 1664 live births at three hospitals in Washington State between 8/91-10/91 and linked with 1268 completed postpartum maternal postal surveys. Non-white race, public insurance payer, unmarried status, and smoking in pregnancy were independent risk factors for non-participation. Among participants, non-white race, unmarried status, and having an infant who was low birthweight, preterm, or discharged late were independent risk factors for prompted response. The inclusion of prompted respondents did not substantially alter the calculated proportion of women rating obstetrical care quality as low, and these figures were similar to proportions estimated for the entire intended cohort using a modification of Drane's method. A one-time mailing of an obstetrical care quality survey can provide information similar to that obtained with more extensive follow-up even though substantial differences may exist between unprompted and prompted respondents, and with adjustment for factors related to non-participation and timing of response, it may be possible to obtain accurate estimation of outcome prevalences for the entire intended cohort.

Comparison of the Musculoskeletal Function Assessment questionnaire with the Short Form-36, the Western Ontario and McMaster Universities Osteoarthritis Index, and the Sickness Impact Profile health-status measures

We compared the reliability, validity, and responsiveness of the Musculoskeletal Function Assessment (MFA) questionnaire with those of three commonly used health-status measures: the Short Form-36 (SF-36), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Sickness Impact Profile (SIP). The MFA, like the other health-status measures, demonstrated good reliability (intraclass correlation coefficients of more than 0.70), good sensitivity and specificity (more than 70 per cent), good criterion validity that correlated with physicians' ratings (p < 0.01), and good construct validity that correlated with the characteristics of the patients (p < 0.01). It also demonstrated better content validity than the other questionnaires, with no ceiling or floor effects for the total score. In addition, it was more responsive than the SF-36; for eight of the eleven comparisons, it was more efficient (relative efficiency of more than 2.00) in measuring changes in function between the baseline values and the values determined at the latest follow-up evaluation. These findings suggest that the MFA can be used to assess the health status of patients who have a musculoskeletal disorder.

Health care utilization for the "newly insured": results from the Washington Basic Health Plan

The risk of providing coverage for low-income people formerly without insurance is unknown. We conducted an evaluation to describe the use of services from 1989-1992 for members of the Basic Health Plan (BHP), a subsidized health insurance program for low-income individuals in the state of Washington. There was evidence of pent-up demand for care for those who had been without insurance for more than a year. Overall, members in the BHP program were not high users of care, although one of the three plans we examined had significantly higher utilization than the other two. BHP total expenditures were comparable to those for state employees and lower than those for Medicaid recipients.

What do women want to know after childbirth?

BACKGROUND

Postpartum women have demonstrated a variety of health care concerns. This study, conducted in Washington state in 1991, investigated predictors of primiparas' and multiparas' desire to receive more information about 18 self-care and baby care topics at 7 weeks postpartum in relation to prenatal class attendance, short postpartum hospital stay, and other variables.

METHODS

Data from 1161 women who completed a survey were analyzed. Percentages of women desiring more information on each topic were calculated stratified by parity; mean numbers of chosen health topics were calculated in relation to prenatal education, length of postpartum hospitalization, maternal age, education, social support, and type of delivery; and association between desire for more information on specific topics and length of postpartum hospitalization, maternal age, maternal education, and social support were calculated.

RESULTS

Over three-fourths of women wanted more information on at least one topic, and the highest percentage wanted more information on exercise, diet, and nutrition; getting along with their other children; and recognizing infant illness. Primiparas and multiparas who desired more information were under 25 years of age and had low levels of social support; in addition, multiparas with unmet information needs had low education and short postpartum stays. Prenatal education was unrelated to postpartum desire for more information.

CONCLUSION

Most postpartum women want self-care and baby care information, a need that is not completely met by prenatal or postpartum education. Postpartum follow-up programs with a strong educational component and special targeting of high-risk women may enable health caregivers to better address this need.

Dissatisfaction and disenrollment in a subsidized managed care program

We studied members of the subsidized Basic Health Plan (BHP)from four managed health care organizations (MHCO). We compared low-income enrollees' and disenrollees' satisfaction with benefits, membership, and care from their MHCOs. Enrollees disenrolled primarily because they became insured through an employer, their income increased, or they moved out of the area. These disenrollees were less satisfied overall and with the amount of premiums and the total amount of medical costs covered. Disenrollees were also less satisfied with the ease and convenience of obtaining care, availability of phone advice, and quality of care. Disenrollees were more likely to be employed or to have a family member in fair or poor health. Satisfaction was high with MHCOs, although it varied considerably by site, particularly with ability to select doctors. Respondents reported affordability the most desired feature and lack of prescription coverage the least desired feature. Overall, disenrollment was not associated highly with dissatisfaction.