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Biomedical subjects

J L Walker

Publications and source records attributed to J L Walker.

At least 55 records · Page 3Linked to original sources
PubMed1994

Prognostic utility of epidermal growth factor receptor overexpression in endometrial adenocarcinoma.

BACKGROUND: Overexpression of epidermal growth factor receptor (EGFR) has been reported in endometrial adenocarcinoma. METHODS: A retrospective analytic study was designed to investigate its prognostic utility. Sixty-nine patients were studied with cell types that included endometrioid (n = 45), papillary serous (n = 16), and clear cell (n = 8). Patients' medical charts and survival data were reviewed. Assessment of EGFR overexpression was done at the protein level by the use of an anti-EGFR polyclonal antibody that reacts with the cytoplasmic membrane glycoprotein receptor in paraffin-embedded tissues. RESULTS: EGFR was overexpressed in 34 (49%) patients in whom immunoreactivity was limited to neoplastic cells. Initial bivariate analysis revealed significant correlations between EGFR immunoreactivity and histologic grade (r = 0.44, P < 0.001), metastasis (r = 0.38, P < 0.001), cell type (r = 0.30, P < 0.01), myometrial invasion (r = 0.30, P < 0.01), and patient age (r = 0.30, P < 0.01). Multiple logistic regression analyses showed that EGFR overexpression and nonendometrioid cell types are two independent statistically significant markers for the presence of metastases. EGFR immunoreactivity can significantly predict myometrial invasion, but after controlling for the histologic grade, its ability of significantly predict invasion was lost. EGFR overexpression was shown to be a statistically significant predictor of survival, even after controlling for patient age, histologic grade, and cell type. CONCLUSIONS: Expression of this oncoprotein may serve as an independent prognostic indicator and a guide to therapy in patients with endometrial cancer.

Adenocarcinoma↗
PubMed1994

Enhancement of functional recovery following a crush lesion to the rat sciatic nerve by exposure to pulsed electromagnetic fields.

Previous studies showed that exposure to pulsed electromagnetic fields (PEMF) produced a 22% increase in the axonal regeneration rate during the first 6 days after crush injury in the rat sciatic nerve. We used the same injury model to assess the effect on functional recovery. The animals were treated with whole body exposure to PEMF (0.3 mT, repetition rate 2 Hz) for 4 h/day during Days 1-5 while held in plastic restrainers. Functional recovery was serially assessed up to Postinjury Day 43 using recently described video imaging of the 1-5 toe spread and the gait-stance duration. Footprint analysis was also used with calculation of a sciatic function index. Those animals treated with PEMF had improved functional recovery, as compared to sham controls, using the tests for video 1-5 toe spread and gait-stance duration (P = 0.001 and P = 0.081, respectively). This effect was found throughout the 43-day recovery period. No effect was found using the sciatic function index. This study confirms that functional recovery after nerve crush lesion is accelerated by PEMF and has broad implications for the clinical use of these fields in the management of nerve injuries.

Animals↗
PubMed1994

Open interstitial brachytherapy for the treatment of local-regional recurrences of uterine corpus and cervix cancer after primary surgery.

Patients who develop locally recurrent uterine corpus or uterine cervix cancer after primary surgery are usually treated with radiotherapy. The optimal radiotherapeutic approach, however, has not been defined. We report the use of exploratory laparotomy, omental pedicle grafting, and intraoperative transperineal interstitial brachytherapy in the treatment of 28 such patients (10 with recurrent corpus and 18 with recurrent cervix cancer). In addition, 22 patients also received perioperative whole pelvic teletherapy while 21 also received a second closed interstitial application. Local control was achieved in 20 patients (71%), but only 10 (36%) continue to be alive without disease after a median of 44 months. Eighteen patients have died (17 of disease) a median of 13 months after open implant. Patients treated with a single implant (n = 7), with side wall involvement (n = 5), with tumors greater than 6 cm in size (n = 4), with a history of previous pelvic irradiation (n = 8), or with persistent disease after open interstitial therapy (n = 8), were not salvaged. Ten patients suffered acute morbidity which included deep venous thrombosis (n = 1), wound separation (n = 1), urinary infection (n = 2), wound infection (n = 2), pneumonia (n = 1), and fever (n = 3). Two other patients experienced chronic non-tumor-related comorbidities. These included a vesicovaginal fistula with a rectovaginal fistula in 1 patient and a small bowel obstruction with a ureteral stricture in another. A single individual suffered from both acute and chronic complications (fever, ureterointestinal fistula).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Extent of disease as an indication for pelvic radiation following radical hysterectomy and bilateral pelvic lymph node dissection in the treatment of stage IB and IIA cervical carcinoma.

The role of adjuvant pelvic radiation following radical hysterectomy and pelvic lymph node dissection in the treatment of stage IB and IIA cervical cancer is controversial. Patients most likely to benefit from postoperative radiation include those with lesions that invade deeply into the cervical stroma, extend into the parametria, or have metastasized to regional lymph nodes. Between 1977 and 1987, 95 patients were treated with this combined regimen at the University of California Irvine Medical Center and Long Beach Memorial Medical Center, including 30 patients with deep cervical stromal invasion alone, 9 patients with parametrial extension alone, 37 patients with lymph node metastasis alone, and 19 patients with both positive nodes and parametrial extension. The estimated 5-year survival for this high-risk population was 67%. Pelvic recurrences alone occurred in 12 (13%) patients, and 14 additional patients (15%) recurred outside of the radiation field. In the node-positive group, the 5-year survival was 78% when the parametrium was not involved but decreased to 39% when parametrial extension was documented (P < 0.05). Patients with grossly involved nodes or multiple nodal metastases were also more likely to recur. Finally, the estimated 5-year survival for patients with deep cervical stromal invasion as the sole indication for radiotherapy was 73%. A retrospective analysis identified tumor grade and cell type also to be of prognostic importance. Severe complications attributable to radiation combined with radical surgery included two small bowel obstructions and one urinary tract fistula. These data suggest that radical hysterectomy, pelvic lymphadenectomy, and adjuvant radiotherapy produce favorable survival results with limited morbidity in patients with high-risk cervical cancer independent of node status except in that subset of patients with both occult parametrial spread and nodal metastasis.

Adult↗
PubMed1994

Effect of Pasteurella haemolytica infection on alpha 1-acid glycoprotein and albumin concentrations in serum and subcutaneous tissue chamber fluid of calves.

Thermoplastic tissue chambers were implanted subcutaneously in the paralumbar fossae of 10 calves. Concentrations of alpha 1-acid glycoprotein (AAG) and albumin in serum and subcutaneous tissue chamber fluid were measured before and after inoculation of Pasteurella haemolytica into tissue chambers. Two months after implantation, serum and tissue chamber fluid samples were collected and all tissue chambers were then inoculated with P haemolytica. Additional serum and chamber fluid samples were collected two, four, six and 10 days after inoculation. The concentrations of AAG and albumin in the samples were measured by radial immunodiffusion assay and the bromcresol method, respectively. P haemolytica inoculation resulted in an increase in the serum and chamber fluid AAG concentrations and an increase in chamber fluid albumin concentrations, suggesting that the proportion of drugs bound to serum and interstitial proteins may be affected by P haemolytica infection.

Animals↗
PubMed1994

Gait-stance duration as a measure of injury and recovery in the rat sciatic nerve model.

The rat sciatic nerve is a well-established animal model for the study of peripheral nerve crush injury. Footprint analysis is the most widely used non-invasive method of measuring functional recovery after injury in this model. However, this method has significant limitations due to inability to obtain clear reproducible prints, especially when the injury is severe, and variation of these prints with gait velocity. In the case of contracture or toe loss, footprint analysis is unreliable. We describe a new technique, gait-stance duration, which is capable of non-invasively quantitating functional recovery in the rat model. This method is not dependent on accurate foot positioning during gait. It utilizes video recording of the animal walking and measures the time each hind foot is in contact with the floor by counting the number of frames that pass. By pairing consecutive steps, it minimizes variation due to changes in velocity and, by calculating a ratio of injured/uninjured hind feet, comparisons to normal gait can be made. This method shows recovery patterns similar to footprint analysis with small inter-animal variability. We believe it has significant advantages over footprint analysis for the measurement of functional recovery in the crushed sciatic nerve rat model.

Animals↗
PubMed1994

Effects of localized Pasteurella haemolytica infection on erythromycin-binding properties of bovine alpha-1-acid glycoprotein, albumin, serum, and tissue chamber fluids.

The in vitro erythromycin-binding properties of bovine alpha-1-acid glycoprotein (AAG) and albumin were studied by using equilibrium dialysis. In addition, the proportions of free erythromycin in bovine serum and tissue chamber fluid before and 4 days after inoculation of subcutaneous tissue chambers with Pasteurella haemolytica were measured. At a concentration of 5 micrograms/ml, erythromycin was moderately bound to AAG (39% +/- 4% free) and was only slightly bound to albumin (86% +/- 2% free). Scatchard analysis of the data describing binding to pure bovine AAG indicated that erythromycin was bound to a single high-affinity (6.45 x 10(4) M-1) site on the protein. At lower total concentrations of erythromycin, the free concentrations of the antibiotic were lower in serum samples collected after infection (49% +/- 3% at 5 micrograms of erythromycin per ml) than in those collected before inoculation (55% +/- 3% at 5 micrograms of erythromycin per ml). Inoculation had no effect on binding to macromolecules in chamber fluids. Inoculated tissue chambers served as a convenient model for studying the effect of infection on drug-macromolecule interactions in interstitial fluid.

Animals↗
PubMed1994

Characterization of epitopes defining two major subclasses of polytropic murine leukemia viruses (MuLVs) which are differentially expressed in mice infected with different ecotropic MuLVs.

Polytropic murine leukemia viruses (MuLVs) arise in mice by recombination of ecotropic MuLVs with endogenous retroviral envelope genes and have been implicated in the induction of hematopoietic proliferative diseases. Inbred mouse strains contain many endogenous sequences which are homologous to the polytropic env genes; however, the extent to which particular sequences participate in the generation of the recombinants is unknown. Previous studies have established antigenic heterogeneity among the env genes of polytropic MuLVs, which may reflect recombination with distinct endogenous genes. In the present study, we have examined many polytropic MuLVs and found that nearly all isolates fall into two mutually exclusive antigenic subclasses on the basis of the ability of their SU proteins to react with one of two monoclonal antibodies, termed Hy 7 and MAb 516. Epitope-mapping studies revealed that reactivity to the two antibodies is dependent on the identity of a single amino acid residue encoded in a variable region of the receptor-binding domain of the env gene. This indicated that the two antigenic subclasses of MuLVs arose by recombination with distinct sets of endogenous genes. Evaluation of polytropic MuLVs in mice revealed distinctly different ratios of the two subclasses after inoculation of different ecotropic MuLVs, suggesting that individual ecotropic MuLVs preferentially recombine with distinct sets of endogenous polytropic env genes.

3T3 Cells↗
PubMed1994

Heel cord advancement in children with spastic equinus deformity.

Heel cord advancement has been advocated for treatment of spastic equinus deformity. Transferring the gastrosoleus anteriorly weakens it by changing the lever arm rather than the resting length. A retrospective review of 90 children with 122 limbs undergoing heel cord advancement revealed 11% excellent, 53% good, and 35% poor results (average follow-up 9.7 years). The results were statistically better in diplegics and community walkers. The better results in previous studies may be due to procedure modifications and shorter follow-up. Since we obtain comparable results with simpler heel cord lengthenings, we no longer do heel cord advancement.

Achilles Tendon↗
PubMed1994

Cost analysis of Hickman catheter insertion at bedside in gynecologic oncology patients.

BACKGROUND: Cost-containment issues are becoming increasingly important in medicine. The current study compares bedside versus operating room insertion of Hickman catheters from a cost and safety standpoint. STUDY DESIGN: A prospective chart review of all patients undergoing Hickman catheter insertion during the study period was performed to determine location of the procedure, rate of successful catheter placement, complications, and cost. RESULTS: Ninety-six patients underwent placement of 108 Hickman catheters during a seven year period. Fifty-three catheters were inserted at bedside while 55 catheters were placed in the operating room. The complication rate was 8 percent for the bedside and 9 percent for the operating room group. Due to anesthesia standby, operating room time, and fluoroscopy, cost analysis revealed a substantial savings of $1,545 per patient if bedside insertion was utilized. CONCLUSIONS: The data indicate that, in select patients, percutaneous insertion of Hickman catheters at bedside is a safe, cost-effective procedure.

Catheterization, Central Venous↗
PubMed1993

Validation of a 20-minute steady-state jog as an estimate of peak oxygen uptake in adolescents.

Distance run tests are often used to estimate peak oxygen uptake (peak VO2) in children. This study examined the concurrent validity of a 20-min steady-state jog (20MSSJ). The sample consisted of 43 boys and 32 girls who performed a 20MSSJ and completed a maximal treadmill test 1 week later. Peak VO2 was measured by indirect calorimetry. Subject characteristics were as follows: boys, mean age = 15.1 +/- 1.0 years, mean peak VO2 = 46.4 +/- 7.7 ml.kg-1 x min-1, mean 20MSSJ = 2.3 +/- 0.5 miles; girls, mean age = 15.3 +/- 1.1 years, mean peak VO2 = 40.4 +/- 5.1 ml.kg-1 x min-1, mean 20MSSJ = 2.1 +/- 0.5 miles. The correlation between 20MSSJ and peak VO2 was .68 across boys and girls. The regression slopes of the boys and girls were common, but the intercepts differed, F (1, 72) = 10.9, p < .05. The influence of weight and skinfold fat was examined. Separate models were developed, and the R for each was increased to .79 (SEE = 4.45 ml.kg-1 x min-1) for the model using weight and .80 (SEE = 4.36 ml.kg-1 x min-1) for the model using sum of skinfolds. The regression equations are as follows: peak VO2 = 35.10 + 6.19 (Run) + 2.96 (Gender) -0.26 (Skinfold fat) peak VO2 = 33.94 + 7.64 (Run) + 5.84 (Gender) -0.18 (Weight) (Run = 20MSSJ performance in miles; Gender; females = 0, males = 1; Skinfold fat = sum of two-site skinfolds in mm; Weight = body weight in kg).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Midline disk herniations of the lumbar spine.

Most lumbar disk displacements occur through the lateral fibers of the posterior longitudinal ligament, whereas only a small percentage occur through the strong midline fibers. The midline disk herniation is identified as a focal midline dural sac compression and is better seen on the lateral myelogram and computed tomography scan. Of the 22 patients in this study, 14 had midline lumbar disk herniations at L4-5. Their presenting symptoms including back pain with sciatica, were similar to those of lateral disk herniations. On physical examination, however, patients commonly had only positive root tension signs with few nerve root deficits. The incidence of cauda equina syndrome was 27%. The results of treatment were much poorer in these patients than results reported with lateral herniations; 41% were good, 27% fair, and 32% poor. Surgical decompression yielded the best results. A wide exposure is usually needed to provide adequate decompression.

Adult↗
PubMed1993

Transportation of children with special seating needs.

As of 1986, all 50 states had implemented mandatory child restraint laws. When used correctly, restraint systems have been proven to reduce the number of fatalities, hospitalizations, and injuries. To date, there is little information regarding compliance with restraint systems for disabled children. There are no data available on fatalities of or injuries to disabled children. This study assessed the restraint system (if any) used in the transportation of disabled children with special restraint needs. We conducted a survey to determine the restraint practices used in transporting these children to school, to our outpatient clinic, and around home. Our survey found that two thirds of the handicapped children reviewed were transported unsafely in at least one mode of transportation. We recommend that health care providers review the transportation needs of their handicapped patients in order to ensure safe transportation.

Adolescent↗
PubMed1993

Thoracic kyphosis associated with a thymic cyst.

Cystic masses of the thymus are usually asymptomatic. Any symptoms are usually related to fluid accumulation and the cyst's accompanying increase in size. The authors report a case presenting with kyphosis and late recognition of the associated thymic cyst. We found no reports in the literature of a thymic cyst preceded by or associated with kyphosis and the mechanisms of this association are unknown.

Adolescent↗
PubMed1993

Southern California Edison's performance standards: an employer's key to quality care delivery.

One of the most significant lessons learned from this process is that setting objectives with performance standards is the key to continuous quality improvement. The critical differences between health administration and health management are threefold: (1) performance standards are developed with clarity, (2) care delivery is monitored and measured against these standards, and (3) improvements are made based on information from these measurements.

California↗
PubMed1992

DNA-based presymptomatic diagnosis of Wilson disease.

Investigation using DNA markers in a family with Wilson disease revealed that an apparently normal child of 10 years of age with non-diagnostic copper biochemistry had the disease. The procedure used linked restriction fragment length polymorphic markers. Demonstration of increased liver copper concentration from a liver biopsy confirmed the diagnosis and the child was started on chelation therapy. Two other asymptomatic siblings were shown, using the same techniques, not to have the disease. Similar analysis was carried out on another family with just one index case.

Chromosomes, Human, Pair 13↗