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Biomedical subjects

H E Schwartz

Publications and source records attributed to H E Schwartz.

16 recordsLinked to original sources
PubMed2000

Effect of oxiplex* films (PEO/CMC) on adhesion formation and reformation in rabbit models and on peritoneal infection in a rat model.

OBJECTIVE: To assess the efficacy of Oxiplex (FzioMed, Inc., San Luis Obispo, CA) barriers. DESIGN: Film of polyethylene oxide and carboxymethylcellulose (Oxiplex) were tested for strength and tissue adherence. Films were selected for evaluation in models for biocompatability and adherence. Three films were selected for evaluation in efficacy studies, and one was evaluated for effects on bacterial peritonitis. Handling characteristics of Oxiplex film were evaluated via laparoscopy. SETTING: University laboratory. PATIENT(S): Rabbits, rats, pigs. INTERVENTION(S): Placement of Oxiplex prototypes at the site of injury. MAIN OUTCOME MEASURE(S): Mechanical properties, biocompatibility, tissue adherence, adhesion development, infection potentiation, and device handling. RESULT(S): Mechanical tests indicated that tensile strength and elongation were inversely correlated. All films tested had excellent tissue adherence properties. Selected films, based on residence time and biocompatibility, prevented adhesion formation in all animals and were highly efficacious in preventing adhesion reformation. The optimal Oxiplex prototype prevented adhesion reformation in 91% of the animals. This Oxiplex film, dyed to allow visualization, prevented adhesion reformation and did not affect bacterial peritonitis. In a laparoscopic model, the Oxiplex film, delivered in FilmSert forceps, via a 5.0-mm trocar, rapidly unfurled and could be easily applied to tissue with strong adherence. CONCLUSION(S): These data show development of an adhesion prevention material that is tissue adherent, can be placed via laparoscopy, and does not affect host resistance.

Absorbable Implants↗
PubMed1995

Dose-dependent response of gamma irradiation on mechanical properties and related biochemical composition of goat bone-patellar tendon-bone allografts.

We studied the effects of gamma irradiation on the dimensions, mechanical and material properties, and mature hydroxypyridinium crosslink density of collagen in goat patellar tendon-bone specimens. Left and right patellar tendon-bone units were removed from 10 adult female goats and were bisected longitudinally. Each tendon half was frozen, and then the left halves were exposed to 4, 6, or 8 Mrad (40,000, 60,000, or 80,000 Gy) of gamma irradiation. The contralateral tendon halves served as controls (no irradiation). Each specimen then was loaded to failure in tension, and its soft-tissue midsubstance was processed to measure collagen content and hydroxypyridinium crosslink density. Dose-dependent reductions in the mechanical properties were found, including 46% (p < 0.01) and 18% (p < 0.05) reductions in maximum force and stiffness, respectively, at 4 Mrad. Similar reductions were noted in material properties, including 37% (p < 0.005) and 8% (p > 0.05) reductions in maximum stress and modulus, respectively, at 4 Mrad. These results are consistent with our previous report involving 2 and 3 Mrad (20,000 and 30,000 Gy) of exposure. We also found significant decreases in hydroxypyridinium crosslink density with 6 Mrad of irradiation (p < 0.05). However, since only one biomechanical parameter (modulus) correlated significantly with only one biochemical measure (hydroxypyridinium crosslink density) (p < 0.05), other possible mechanisms also are being explored to more fully explain these dose-dependent changes.

Analysis of Variance↗
PubMed1993

Patients' rights in a nursing home.

Under state and federal law, nursing home residents have many rights, including the right to be treated with respect, to receive reasonable accommodation to individual needs, to not be abused, to be free from unwarranted restraints, to refuse treatment, and to participate in treatment planning. Physicians need a working knowledge of certain fundamental legal concepts in order to help patients, particularly with regard to withholding or withdrawal of life-sustaining treatment.

Aged↗
PubMed1992

Restriction fragment length polymorphism analysis of ERBB2 oncogene by capillary electrophoresis.

Capillary electrophoresis (CE) with a sieving buffer containing ethidium bromide was applied to the detection of PCR-amplified RFLP samples. With CE, in contrast to agarose gel electrophoresis, run times are short, i.e., typically less than 30 min, the capillary can be re-used, and full automation is feasible. The addition of ethidium bromide to the buffer system in conjunction with a field amplification injection technique led to increased sample detectability and resolution. Migration time precision was better than 0.2% RSD with a approximately 12-bp resolution for the DNA fragment sizes of interest. RFLP samples were analyzed for homo- or heterozygosity based on the presence of 500- and/or 520-bp DNA fragments. Special software was used to correct for run-to-run migration time variations, thus facilitating genotype assignment.

DNA↗
PubMed1991

Analysis of DNA restriction fragments and polymerase chain reaction products towards detection of the AIDS (HIV-1) virus in blood.

A high-performance capillary electrophoresis system with a polysiloxane-coated capillary and polymeric buffer additives was investigated for the analysis of DNA restriction fragments and polymerase chain reaction (PCR) products. Mobility data and Ferguson plots of the DNA fragments at different polymer (hydroxypropylmethylcellulose) concentrations indicated that effective molecular sieving was obtained consistent with existing data of conventional gel electrophoresis and with recent HPCE data. The precision and peak efficiency were excellent and the system was applied to the analysis of specific co-amplified DNA sequences (HIV-1 and HLA-DQ-alpha). After PCR, ultrafiltration was used in the sample preparation step to desalt the sample and to remove superfluous PCR reaction products. Electrokinetic injection was used for sample introduction into the capillary. The addition of ethidium bromide to the buffer resulted in longer migration times of DNA fragments and better peak resolution. During HPCE, an artifact associated with dilute DNA solutions leading to the appearance of extra peaks in the electropherogram was found.

Blood↗
PubMed1978

Recovery of eighth nerve function after cerebellopontine angle surgery.

Retrocochlear lesions cause typical patterns of hearing loss as detailed in special audiometric tests. Such losses, however, may be temporary deficits. Indeed, return to near normalcy following severely depressed auditory function is documented in this article. Conservative surgery on lesions influencing eighth nerve function should be considered. This is not to say that neoplasia can be partially removed, but rather that when tumors can be resected while preserving the cochlear nerve, this should be done inasmuch as good hearing levels may be restored.

Auditory Threshold↗
PubMedDate not supplied

Bilateral first branchial cleft cysts: case report and literature review.

Instances of first branchial cleft anomalies are quite uncommon. A patient with a first branchial cleft cyst was seen and surgically treated at UCLA Hospital in 1972. Three years later he developed a similar lesion on the opposite side of his neck and this also was surgically excised. A review of the literature has revealed only one prior report of bilateral first branchial cleft anomalies. The embryogenesis, diagnosis, and surgical management of these lesions are discussed in this paper.

Branchioma↗
PubMedDate not supplied

Aggressive fibromatosis of the tongue.

Fibromatoses are uncommon, locally aggressive lesions that may involve the structures of the head and neck. They are most commonly found in and along the fascial planes of the neck muscles but can involve other structures, including the oral cavity, nose, nasopharynx or paranasal sinuses. An unusual case of an extra-abdominal desmoid tumor is presented and a review of the anatomical, clinical and pathological features of these tumors is discussed.

Adolescent↗