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Biomedical subjects

E Y Cheng

Publications and source records attributed to E Y Cheng.

At least 19 recordsLinked to original sources
PubMed2000

Evaluation of the feasibility of and results of measuring health-status changes in patients undergoing surgical treatment for skeletal metastases.

The goal of treating patients with skeletal metastases is to decrease pain and improve or maintain physical function. Assessment of the effectiveness of treatment should therefore include evaluation of patient-rated measures of quality of life. The primary objective of the study was to determine the feasibility of studying the effect of surgical treatment of skeletal metastases on quality of life. The secondary objective was to provide data that begin to characterize this effect. The characteristics of patients with skeletal metastases are heterogeneous, patient enrollment in the study may be low, high attrition occurs secondary to death, and well accepted health-status measures (such as the Short Form-36) may be ineffective at detecting changes in health status; therefore, it is difficult to study these patients. High attrition and adjuvant treatment with radiation or chemotherapy made it impractical to draw firm conclusions about the effect of surgical treatment, but a trend toward improvement in selected health-status measures for both physical and mental health was noted. Analysis of patient-rated health-status scores as predictors of survival indicates that improvement in these scores 6 weeks after surgery is associated with an increase in the length of survival following surgery.

Adult↗
PubMed2000

Urologic tissue engineering with small-intestinal submucosa: potential clinical applications.

Small-intestinal submucosa (SIS) is a unique biomaterial that has been shown to induce tissue-specific regeneration in numerous organ systems. In the urinary tract, animal studies have demonstrated that SIS promotes functional bladder regeneration. Other preliminary studies have suggested that SIS may also be extremely useful for several other types of urologic surgery application where new tissue is needed or reinforcement of native structures is desired. This article reviews past and current work with SIS in the urinary tract and focuses on applications that will likely have future clinical utility.

Biocompatible Materials↗
PubMed2000

Differences between generalists and specialists in characteristics of patients receiving gastrointestinal procedures.

BACKGROUND: As a result of market forces and maturing technology, generalists are currently providing services, such as colonoscopy, that in the past were deemed the realm of specialists. OBJECTIVE: To determine whether there were differences in patient characteristics, procedure complexity, and clinical indications when gastrointestinal endoscopic procedures were provided by generalists versus specialists. DESIGN: Retrospective cohort study. PATIENTS: A random 5% sample of aged Medicare beneficiaries who underwent rigid and flexible sigmoidoscopy, colonoscopy, and esophagogastroduodenoscopy (EGD) performed by specialists (gastroenterologists, general surgeons, and colorectal surgeons) or generalists (general practitioners, family practitioners, and general internists). MEASUREMENTS: Characteristics of patients, indications for the procedure, procedural complexity, and place of service were compared between generalists and specialists using descriptive statistics and logistic regression. MAIN RESULTS: Our sample population had 167,347 gastrointestinal endoscopies. Generalists performed 7.7% of the 57, 221 colonoscopies, 8.7% of the 62,469 EGDs, 42.7% of the 38,261 flexible sigmoidoscopies, and 35.2% of the 9,396 rigid sigmoidoscopies. Age and gender of patients were similar between generalists and specialists, but white patients were more likely to receive complex endoscopy from specialists. After adjusting for patient differences in age, race, and gender, generalists were more likely to have provided a simple diagnostic procedure (odds ratio [OR] 4.2; 95% confidence interval [95% CI] 4.0, 4.4), perform the procedure for examination and screening purposes (OR 4.9; 95% CI, 4. 3 to 5.6), and provide these procedures in rural areas (OR 1.5; 95% CI 1.4 to 1.6). CONCLUSIONS: Although generalists perform the full spectrum of gastrointestinal endoscopies, their procedures are often of lower complexity and less likely to have been performed for investigating severe morbidities.

Aged↗
PubMed2000

The workforce in otolaryngology-head and neck surgery: moving into the next millennium.

OBJECTIVE: The goal was to examine the current scope of otolaryngologists' practices, their geographic distribution, and the roles otolaryngologists and other specialists play in caring for patients with otolaryngic and related conditions of the head and neck. STUDY DESIGN: A large national survey and administrative claims databases were examined to develop practice profiles and compile a physician supply for otolaryngology. A focus group of otolaryngologists provided information to model future scenarios. RESULTS: The current and predicted workforce supply and demographics are at a satisfactory level and are decreasing as a proportion of the increasing population. Empiric data analysis supports the diverse nature of an otolaryngologist's practice and the unique role for otolaryngologists that is not shared by many other providers. Together with the focus group results, the study points to areas for which more background and training are warranted. CONCLUSIONS: This study represents a first step in a process to form coherent workforce recommendations for the field of otolaryngology.

Adult↗
PubMed2000

Bioengineering organs using small intestinal submucosa scaffolds: in vivo tissue-engineering technology.

Tissue engineering is a promising field of research that has the potential to revolutionize urinary bladder reconstruction. Currently, two techniques for the induction of bladder regeneration are being researched. The first, the in vivo technique, involves the use of a biodegradable scaffold that the host bladder can use to remodel and regenerate. This technique takes advantage of the cell's natural ability to heal or regenerate itself back to a normal state. The second technology, the in vitro technique, involves establishment of primary cell cultures from the host's native bladder. These cells are seeded on a biodegradable scaffold to create a composite graft that is then transplanted back into the host for continuation of the regeneration process. Clearly, both techniques have advantages and disadvantages, and both will have some role in future urinary reconstruction. To date, the most successful results utilizing in vivo techniques have been with small intestinal submucosa (SIS). In this article, we discuss in vivo tissue engineering technology and the preclinical studies that have been performed utilizing SIS for urinary tract regeneration.

Animals↗
PubMed2000

Fractures in large-segment allografts.

Segment skeletal defects that result from resection of a malignant bone neoplasm commonly are reconstructed with large segment allografts. Excellent functional results after these reconstructions and significant complications have been reported. Although it is known that a common complication seen with the use of allografts is allograft fracture, the factors associated with allograft fracture are not entirely clear. In this study, the hypothesis was examined that allograft reconstructions, which use internal fixation devices that penetrate the cortex of the allograft, are associated with an increased risk of fracture. Findings from large segment allograft reconstructions in 74 patients with a minimum followup of 36 months were studied. These 74 patients include 35 patients whose outcomes were reported previously and now have additional followup and 39 patients whose outcomes are being reported for the first time. Thirty-one of the 74 (42%) allografts fractured, and the mean time to fracture was 26 months. When the fixation techniques resulted in cortical penetration of the allograft, fractures occurred in 27 of the 43 (63%) allografts, and when fixation of the graft to the host bone required no cortical penetration, only four of the 31 (13%) allografts fractured. Fractures occurred in 12 of 15 (80%) tibial allografts and in only two of 17 (12%) proximal femoral allografts; however, the anatomic site was not statistically independent of method of fixation because 14 of the 15 tibial grafts had cortical penetration and 15 of the 17 proximal femoral grafts had no cortical penetration. The authors' analysis indicates that internal fixation devices that require cortical penetration are associated with an increased risk of allograft fracture.

Adolescent↗
PubMed2000

Use of active noise cancellation devices in caregivers in the intensive care unit.

OBJECTIVE: Recent development of noise cancellation devices may offer relief from noise in the intensive care unit environment. This study was conducted to evaluate the effect of noise cancellation devices on subjective hearing assessment by caregivers in the intensive care units. DESIGN: Randomized, double-blind. SETTING: Adult medical intensive care unit and pediatric intensive care unit of a teaching hospital. SUBJECTS: Caregivers of patients, including nurses, parents, respiratory therapists, and nursing assistants from a medical intensive care unit and pediatric intensive care, were enrolled in the study. INTERVENTION: Each participant was asked to wear the headphones, functional or nonfunctional noise cancellation devices, for a minimum of 30 mins. MEASUREMENTS: Subjective ambient noise level was assessed on a 10-point visual analog scale (VAS) before and during headphone use by each participant. Headphone comfort and the preference of the caregiver to wear the headphone were also evaluated on a 10-point VAS. Simultaneously, objective measurement of noise was done with a sound level meter using the decibel-A scale and at each of nine octave bands at each bedspace. RESULTS: The functional headphones significantly reduced the subjective assessment of noise by 2 (out of 10) VAS points (p < 0.05) in environments of equal objective noise profiles, based on decibel-A and octave band assessments. CONCLUSION: Noise cancellation devices improve subjective assessment of noise in caretakers. The benefit of these devices on hearing loss needs further evaluation in caregivers and critically ill patients.

Adult↗
PubMed2000

Coculture of bladder urothelial and smooth muscle cells on small intestinal submucosa: potential applications for tissue engineering technology.

PURPOSE: Small intestinal submucosa is a xenogenic, acellular, collagen rich membrane with inherent growth factors that has previously been shown to promote in vivo bladder regeneration. We evaluate in vitro use of small intestinal submucosa to support the individual and combined growth of bladder urothelial cells and smooth muscle cells for potential use in tissue engineering techniques, and in vitro study of the cellular mechanisms involved in bladder regeneration. MATERIALS AND METHODS: Primary cultures of human bladder urothelial cells and smooth muscle cells were established using standard enzymatic digestion or explant techniques. Cultured cells were then seeded on small intestinal submucosa at a density of 1 x 105 cells per cm.2, incubated and harvested at 3, 7, 14 and 28 days. The 5 separate culture methods evaluated were urothelial cells seeded alone on the mucosal surface of small intestinal submucosa, smooth muscle cells seeded alone on the mucosal surface, layered coculture of smooth muscle cells seeded on the mucosal surface followed by urothelial cells 1 hour later, sandwich coculture of smooth muscle cells seeded on the serosal surface followed by seeding of urothelial cells on the mucosal surface 24 hours later, and mixed coculture of urothelial cells and smooth muscle cells mixed and seeded together on the mucosal surface. Following harvesting at the designated time points small intestinal submucosa cell constructs were formalin fixed and processed for routine histology including Masson trichrome staining. Specific cell growth characteristics were studied with particular attention to cell morphology, cell proliferation and layering, cell sorting, presence of a pseudostratified urothelium and matrix penetrance. To aid in the identification of smooth muscle cells and urothelial cells in the coculture groups, immunohistochemical analysis was performed with antibodies to alpha-smooth muscle actin and cytokeratins AE1/AE3. RESULTS: Progressive 3-dimensional growth of urothelial cells and smooth muscle cells occurred in vitro on small intestinal submucosa. When seeded alone urothelial cells and smooth muscle cells grew in several layers with minimal to no matrix penetration. In contrast, layered, mixed and sandwich coculture methods demonstrated significant enhancement of smooth muscle cell penetration of the membrane. The layered and sandwich coculture techniques resulted in organized cell sorting, formation of a well-defined pseudostratified urothelium and multilayered smooth muscle cells with enhanced matrix penetration. With the mixed coculture technique there was no evidence of cell sorting although matrix penetrance by the smooth muscle cells was evident. Immunohistochemical studies demonstrated that urothelial cells and smooth muscle cells maintain the expression of the phenotypic markers of differentiation alpha-smooth muscle actin and cytokeratins AE1/AE3. CONCLUSIONS: Small intestinal submucosa supports the 3-dimensional growth of human bladder cells in vitro. Successful combined growth of bladder cells on small intestinal submucosa with different seeding techniques has important future clinical implications with respect to tissue engineering technology. The results of our study demonstrate that there are important smooth muscle cell-epithelial cell interactions involved in determining the type of in vitro cell growth that occurs on small intestinal submucosa. Small intestinal submucosa is a valuable tool for in vitro study of the cell-cell and cell-matrix interactions that are involved in regeneration and various disease processes of the bladder.

Child↗
PubMed2000

Total urogenital complex mobilization in female patients with exstrophy.

PURPOSE: Female bladder exstrophy/epispadias has traditionally been approached in a staged fashion. This approach results in a vagina that remains in an abnormal position on the anterior abdominal wall. We present a surgical correction of the female exstrophy/epispadias urogenital complex with total mobilization that returns the vagina to its proper anatomical position. MATERIALS AND METHODS: Since 1997, 7 female patients presenting with variants of the exstrophy/epispadias complex have undergone surgical repair using total urogenital complex mobilization. Of the patients 1 newborn and 2 school-age children had classic bladder exstrophy, 2 school-age children had cloacal exstrophy and 2 school-age children had primary epispadias. Total urogenital complex mobilization involved treatment of the urethra and vagina as a single unit. Complete disassembly of the pelvic diaphragm or floor anterior to the rectum was required to reposition the urethra and vagina to their proper anatomical positions in the perineum. The pelvic diaphragm was then reconstructed anterior to the urogenital complex to recapitulate the normal female pelvic floor anatomy. RESULTS: All patients have an anatomically correct position of the urogenital complex. All the vaginas reached the perineum without the need for skin flaps. All patients have adequate vaginal caliber without evidence of stenosis. CONCLUSIONS: The female with exstrophy/epispadias has unique anatomical defects in the urogenital complex that require special attention. Anterior displacement of the bladder, urethra and vagina with concomitant lack of development of the anterior pelvic floor musculature make a single stage, total urogenital complex mobilization repair ideal for this population. The results of this technique have been functionally and cosmetically pleasing. Whether repositioning the urogenital complex into the normal anatomical position will improve bladder dysfunction and urinary continence rates, and decrease or eliminate the need for future surgery will only be known after further long-term followup has been completed.

Bladder Exstrophy↗
PubMed2000

Echogenic intracardiac focus in 2nd-trimester fetuses with trisomy 21: usefulness as a US marker.

PURPOSE: To determine whether there is a relationship between the presence of an echogenic intracardiac focus in 2nd-trimester fetuses and trisomy 21 (Down syndrome). MATERIALS AND METHODS: A complete genetic ultrasonographic (US) scan was obtained in 3,303 consecutive fetuses with an estimated gestational age of 14.0-24.0 weeks (mean +/- SD, 17.1 weeks +/- 1.75). US was performed in a prospective fashion without any knowledge of karyotype and included assessment of any potential echogenic intracardiac focus (ie, calcified papillary muscle). Karyotypes were obtained in all fetuses. Maternal ages ranged from 13.0 to 47.4 years (mean, 35.1 years +/- 5.1). The prevalence of Down syndrome in this population was 1.6% (53 of 3,303 fetuses). RESULTS: An echogenic intracardiac focus was seen in 147 of the 3,192 karyotypically normal fetuses (4.6%) and 16 of the 53 fetuses with trisomy 21 (30%). The positive predictive value (PPV) of an echogenic intracardiac focus in this high-risk population was 9.8%; sensitivity, 30%; specificity, 95%; likelihood ratio, 6.6; and relative risk (RR), 8.2 (P <.001). For a sonographically isolated echogenic intracardiac focus, the PPV was 3.7%; sensitivity, 19%; specificity, 95%; likelihood ratio, 4.2; and RR, 4.8 (P =.002). CONCLUSION: A sonographically isolated echogenic intracardiac focus (no other anomalies or markers noted on a complete genetic sonogram) was associated in our high-risk population with a 4.8-fold (95% CI: 1.8, 12.5) increase in RR for trisomy 21 (P =.002).

Adolescent↗
PubMed2000

Evaluation and treatment of children with neurogenic bladders.

The evaluation and treatment of children with neurogenic bladders can be difficult because of the complexity of the neurologic deficit and the subjectivity of the history and physical exam. The primary emphasis of the physicians caring for these children should be to preserve renal function and facilitate continence when possible. As knowledge of both normal and abnormal lower urinary-tract dynamics increases, so does the ability to care for children with abnormal bladder dynamics caused by various neurologic conditions. With recent advancements in medical and surgical treatment of the neurogenic bladder, most children can maintain adequate renal function and attain urinary continence. This article reviews the pertinent innervation, anatomy, and physiology of the lower urinary tract, and discusses current evaluation and treatment of children with neurogenic bladders.

Child↗
PubMed2000

Synovial sarcoma. Large size predicts poor outcome.

A consecutive series of 38 patients with synovial sarcoma diagnosed and treated in a consistent fashion from 1976 to 1994 was reviewed for prognostic variables. The histologic specimens were reviewed and confirmed by one pathologist. There was a minimum 4-year followup for all surviving patients and no patients were lost to followup. The treatment protocol consisted of surgical excision with a wide or radical margin and limb preservation when possible. In those patients in whom the surgical margin was undefined or was less than a wide margin, perioperative radiation therapy was used. Four patients presented with metastatic disease and all died of their disease. Thirty-four patients had localized disease at presentation. Variables considered in stratifying outcomes included histologic grade, histologic subtype, surgical margin, presence or absence of local recurrence, age, and size of tumor. Of the 34 patients without metastasis there was a strong statistical association between size of tumor and survival: 17 patients with tumors less than 5 cm indiameter had a 100% survival, 12 patients with tumors 5 cm to 10 cm had a 75% survival, and five patients with tumors greater than 10 cm had a 20% survival. The authors urge that a multicenter trial for neoadjuvant chemotherapy be initiated for patients presenting with a synovial sarcoma greater than 10 cm in diameter.

Adolescent↗
PubMed1999

Lumbosacral chordoma. Prognostic factors and treatment.

STUDY DESIGN: Retrospective analysis. OBJECTIVES: To analyze the prognostic factors in patients with chordomas, the success of various treatments, the diagnostic value of open versus needle biopsy, the neurologic impairment after sacral nerve resection, and the clinical presentation and site of origin. SUMMARY OF BACKGROUND DATA: Staging of chordomas has not been of much value, compared with other bone tumors, because for chordomas, grade is similar, metastasis is infrequent at presentation, and the prognostic significance of size is uncertain. METHODS: A review of patients with chordoma from 1965 through 1996 found 23 cases (mean age of patients, 55 years). The mean follow-up was 84 months. Mean tumor size was 81 mm (range, 35-135 mm), location was lumbar (n = 6), S1 (n = 4), S2 (n = 3), S3 (n = 7), S4 (n = 2), and S5 (n = 1). RESULTS: No tumors were found in the higher sacrum (S1-S2) alone, without involvement of the lower sacrum. Survival analysis at 5 years showed overall survival (OS) 86%, continuous disease-free survival (CDFS) 58%, and local recurrence-free survival (LRFS) 60%. The location of tumor, defined by highest level of involvement (lumbar vs. sacrum) was of prognostic significance for OS (P = 0.01; log-rank test), CDFS (P = 0.036), but not for LRFS (P = 0.189). Results of multivariate regression showed that location was significant for OS (P = 0.007), CDFS (P = 0.008), and LRFS (P = 0.001). For patients with positive margins (n = 16), initial radiation correlated with longer CDFS (P = 0.002; Mantel-Cox) and LRFS (P = 0.005, Mantel-Cox), but was not significant for OS (P = 0.41). For patients who received no radiation, a positive margin correlated with a shorter CDFS (P = 0.04), a trend to shorter LRFS (P = 0.08), but no difference in OS. Therefore, both a tumor-free margin and initial radiation correlated with a longer survival. No patients had urinary or bowel dysfunction when both S3 nerves were preserved. If one S3 nerve was preserved, 1 of 3 patients had partial urinary incontinence and 2 of 3 patients required bowel medications. If both S3 nerves were resected, all patients required intermittent urinary catheterization and bowel medications. If both S2 nerves were resected, there was complete urinary and bowel incontinence. CONCLUSIONS: The highest level of tumor involvement was prognostically significant for OS, CDFS, and LRFS. Radiation was of value when complete excision was not achieved. Bilateral S3 nerve preservation is necessary to ensure retention of normal urinary and bowel function.

Adult↗
PubMed1999

HRad17, a human homologue of the Schizosaccharomyces pombe checkpoint gene rad17, is overexpressed in colon carcinoma.

Using the palindromic PCR-cDNA display method, we have cloned a novel gene overexpressed by human colon carcinoma relative to normal colon. Among normal tissues examined, only testis expresses it at a high level. Sequence analysis revealed its extensive homology with checkpoint genes rad17 of Schizosaccharomyces pombe and RAD24 of Saccharomyces cerevisiae. This novel gene designated as hRad17 is localized to chromosome 5q12,13.1, a region known to be deleted in a variety of human cancers. Promoter region and one pseudogene of hRad17 have been identified. Whereas the increased expression of hRad17 by human colon carcinomas may be related to the known resistance of these cells to DNA-damaging agents during therapy, the deletion of hRad17 in a variety of cancers may predispose them to increased rate of mutation and heightened sensitivity to DNA-damaging agents, including radiation and anticancer drugs.

Animals↗
PubMed1999

Role of angiotensin II in bladder smooth muscle growth and function.

Preliminary studies by our group and others indicate that angiotensin II may have an important role in the cellular regulation of smooth muscle growth and collagen production in the bladder. The exact mechanisms in which angiotensin II elicits its cellular effects are not known. Given the available information thus far, we hypothesize the following (see Figure 2): 1) Outlet obstruction of the bladder causes increased cell stretch/strain which in turn induces the local production of angiotensin II. Angiotensin II may also influence cell stretch/strain via its direct effects on bladder tone. 2) Angiotensin II then acts as a trophic factor in the bladder wall to cause smooth muscle cell hypertrophy/hyperplasia and increased collagen production via an autocrine and/or paracrine pathway. 3) The cellular effect(s) of angiotensin II may be mediated by secondary growth factors such as bFGF and TGFb Much more extensive research is certainly needed to reveal whether some part, or all of this hypothesis is correct. If angiotensin II is indeed active in regulating muscle and collagen changes in the pathologic bladder, then the clinical implications are extremely exciting since numerous pharmacologic agents are now available which can either inhibit angiotensin II production and/or block receptor mediated events. These agents may prove to be extremely useful in the clinical management of the neurogenic bladder in which obstructive changes may be prevented and potentially reversed. Despite this, caution must be exercised with regard to the potential use of any medications which alter the systemic renin-angiotensin system in the pediatric population since some research has suggested that an intact system may be necessary for the normal development of some organs, including the kidney.

Angiotensin II↗
PubMed1999

Analysis of a paracentric inversion in human oocytes: nonhomologous pairing in pachytene.

A cytological analysis of the pairing configurations in meiosis in a 19-week human fetus with a de novo paracentric inversion of chromosome 7 (q11.23)(q21.1) is reported, using fluorescent in situ hybridization with a chromosome 7 DNA library, a DNA probe for the centromeric region of chromosome 7, and a probe for the William Syndrome Critical Region (WSCR) at 7q11.23. Of 1079 pachytene cells, 58% exhibited complete heterosynapsis of the inverted region while only 10.3% of cells exhibited the expected loop formation. Meiotic progression was observed to be normal.

Chromosome Inversion↗