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Biomedical subjects

J C Price

Publications and source records attributed to J C Price.

At least 73 records · Page 4Linked to original sources
PubMed1990

Esophageal reflux and secondary malignant neoplasia at laryngoesophagectomy.

Pathologic evidence of gastroesophageal reflux demonstrated by either Barrett's esophagus or esophagitis was present in 33% of patients undergoing laryngopharynoesophagectomy, while secondary esophageal squamous cell carcinomas were present in 25% of the specimens. Overall, 54% of all the patients undergoing laryngopharyngoesophagectomy had esophageal disease. This incidence of reflux and secondary esophageal malignant neoplasia is higher than in the general population. Careful assessment of the patient's preoperative history for gastroesophageal reflux, contrast swallowing studies, and esophagoscopies correctly diagnosed most but not all of the esophageal lesions found on pathologic examination. Interestingly, all of the esophageal carcinomas removed in the laryngopharyngoesophagectomy specimens were small and sometimes not evident clinically. Although gastroesophageal reflux has been postulated as an additional etiologic agent in the development of laryngeal carcinoma, all the patients in our study had heavy alcohol and tobacco consumption, and therefore reflux could not be evaluated separately as a risk factor.

Adult↗
PubMed1990

Estimated fetal radiation dose from multislice CT studies.

It is often necessary to estimate the dose of radiation to a fetus from a series of CT scans. To assist in making this process easier and more accurate, we measured fetal doses in an adult anthropomorphic phantom for four CT scanners: Picker 1200, Siemens DRH, GE 9800, and GE 8800. Measurements were made at four kilovoltages (100, 120, 130, and 140 kVp), for 2-, 5-, 8-, and 10-mm thicknesses, for two scanning angles (360 degrees and 398 degrees) and for two patient orientations (prone and supine). The fetal-dose estimates are based on the CT dose index measured by using a pencil ionization chamber at the center position of a 16-cm-diameter cylindrical phantom. Comparison with data from other investigators shows reasonable agreement when phantom differences, X-ray tube output, and equipment calibration are considered.

Female↗
PubMed1989

Effect of drug (core) particle size on the dissolution of theophylline from microspheres made from low molecular weight cellulose acetate propionate.

Three particle sizes (450, 120, and 5 microns) of theophylline were encapsulated in low molecular weight cellulose acetate propionate (intrinsic viscosity, 1.08 dl/g) by the solvent evaporation method. The theoretical drug content for all the batches of microspheres was 50% (w/w). Particle size analysis revealed that about 50% of the microspheres containing the large theophylline crystals (average length of 450 microns) were greater than 500 microns in diameter, whereas only about 35% of the microspheres containing the medium drug crystals (average length of 120 microns) were greater than 500 microns in diameter. The drug content of the larger microspheres prepared from the large drug crystals and the medium drug crystals was much greater than the theoretical drug content (50%, w/w); however, the drug content of all the batches of microspheres containing micronized drug was close to 50% (w/w). Release of the drug in simulated intestinal fluid was very rapid from microspheres containing large and medium drug crystals, while release was slower and more predictable from microspheres made from micronized drug.

Cellulose↗
PubMed1989

Modification of gelatin beadlets for zero-order sustained release.

A three-phase suspension process was used for the preparation of gelatin beadlets containing succinylsulfathiazole. When the beadlets were hardened with 10% formalin at 5 degrees C for varying periods of time up to 24 hr, the 6-hr hardening time gave the slowest release rate. Drug release rate from gelatin beadlets was slower in simulated gastric fluid (SGF) than in simulated intestinal fluid (SIF) but the sustained effect was too limited to be useful for most applications. When the hardened gelatin beadlets were coated with cellulose acetate butyrate (CAB) by an emulsion-solvent evaporation method, a more pronounced sustained effect and a nearly zero-order release were found in SIF. The effects of the amount of gelatin used, the amount of CAB employed, and the length of hardening time on drug release were investigated. The treatment of gelatin beadlets with formalin reduced the swelling action of gelatin in aqueous medium. A nonzero-order drug release rate was observed when the gelatin swelled sufficiently to rupture the CAB coating. The drug release rate can be adjusted by using different ratios of hardened gelatin beadlets and CAB coating in which the gelatin enhances the release rate and the CAB serves as a barrier.

Capsules↗
PubMed1988

The disaggregation of calcium-depleted casein micelles.

The effect of depletion of Ca2+ on the composition and size distribution of casein micelles in milk has been examined using chemical analysis, size exclusion chromatography, fast protein liquid chromatography, turbidimetry and photon correlation spectroscopy. Partial removal of Ca2+ by EDTA and subsequent dialysis resulted in disaggregation of some of the casein micelles; as the EDTA concentration increased, the proportions of Ca2+ and phosphate relative to protein in the micelles remaining intact decreased. However, the composition of the intact micelles, with respect to the different caseins, and the number-frequency size distribution were essentially unchanged.

Animals↗
PubMed1988

Compound pharyngeal myocutaneous flap.

Rehabilitation of major palatal ablative defects associated with lateral composite resection of the tonsil, base of tongue, and/or hemimandible is a difficult problem. Palatal reconstruction is described with emphasis on the compound medially based posterior pharyngeal, pectoralis major myocutaneous flap, which we have found to be an effective and reliable means of reconstructing these defects.

Humans↗
PubMed1988

Aliphatic polyesters and cellulose-based polymers for controlled release applications.

The general technologies for fabricating drug delivery systems are briefly discussed in the present review. Furthermore, two types of commonly used polymers, biodegradable aliphatic polyesters for parenteral administration and cellulose-based polymers for oral uses, are presented by means of selected examples of their properties and applications to control drug release.

Cellulose↗
PubMed1988

The versatile midface degloving approach.

The exposure obtained using the degloving approach is superb and the absence of resultant facial scar or deformity provides a dramatic new addition to the otolaryngologist's surgical repertoire. The advantages of the degloving technique in exposure of the midface, nasal cavities, paranasal sinuses, nasopharynx, skull base, and clivus have led to its increasing importance in the otolaryngology literature. Within 2 years of the technique's introduction in our department, it had been used 48 times for a wide variety of problems, including inverting papilloma, juvenile angiofibroma, chordoma and selected cases of fungal disease of the sinuses. This article describes the procedure, reports the results from a panel of 48 patients, and discusses potential complications. The authors' experience with this procedure indicates that it should become a procedure of choice for management of inverting papilloma and juvenile angiofibroma, as well as a major alternative method in many other circumstances.

Face↗
PubMed1988

The pericranial flap for reconstruction of anterior skull base defects.

In 1981, the senior author first reported the use of the pericranial flap for support of the brain following resection of the anterior skull base. Since the initial report, considerable experience has been gained with this flap. It is currently deployed via a bifrontal craniotomy and is placed primarily as a support beneath the frontal lobes. The pericranial flap may also be used to repair dural laceration and defects. The sinonasal surface is routinely grafted with split-thickness skin or dermis. This technique provides an excellent barrier between the sinonasal cavity and the cerebrospinal fluid, establishing a tough, fibrous platform. Herniation of intracranial contents has not occurred. One major complication has been reported in which radiation necrosis occurred during postoperative therapy, leading to progressive devitalization of the pericranial flap. Ultimately, dural repair and closure with a latissimus dorsi free flap was required. The pericranial flap repair of anterior skull base defects has a 90% complication-free and 95% overall success rate. It is simple and extremely effective. Bone grafting has not been necessary in our experience.

Adult↗
PubMed1988

3-D CT for cranial facial and laryngeal surgery.

Three-dimensional imaging is a new digital technology which interpolates two-dimensional computer tomography information to render a "life-like" anatomic display of the diagnostic information. We have found that this new methodology significantly improves the assessment and therapy of patients undergoing surgical procedures of the head and neck. The technique has been used in cranial-facial and laryngeal pathology, and in preoperative planning of tumor resection, particularly skull-base neoplasms. The use of three-dimensional computer tomography improves the display of the location and volume of pathology and affords accurate therapeutic and surgical planning. The choice and extent of surgery is better defined, and precise bone removal can be performed. In reconstructive surgery, an accurate prefabricated model of the bony defect can be made to aid reconstruction. Representative cases demonstrating the use of three-dimensional computer tomography in head and neck surgery, and its benefits in saving operative time and improving the postoperative result, will be discussed.

Child, Preschool↗
PubMed1988

Recovery of phenytoin from solutions of caseinate salts and calcium chloride.

The recovery of phenytoin from solutions of intact protein components of enteral nutrition products was studied. Diluted phenytoin oral suspension was added to 10 1-mL samples of solutions of sodium caseinate, calcium caseinate, a mixture of sodium and calcium caseinates, and calcium chloride as well as to 10 1-mL samples of a distilled water control to produce theoretical concentrations of 10 micrograms/mL. The samples were filtered using an ultrafiltration technique and assayed for phenytoin concentration by high-performance liquid chromatography. The mean concentration of phenytoin in the filtrates of the test samples was significantly lower than the mean concentration in the control samples. The recovery of phenytoin from sodium caseinate solutions was significantly lower than that from solutions of calcium caseinate or calcium chloride. There was no significant difference between recovery of phenytoin from sodium caseinate solutions and that from solutions of sodium and calcium caseinates. Decreased phenytoin absorption from enteral nutrient solutions in vitro may be associated with the presence of caseinate salts and calcium chloride. However, this relationship cannot be extrapolated to in vivo absorption.

Calcium Chloride↗
PubMed1986

Advanced laryngeal cancer. Relevance of pathologic stage to survival and therapy.

Sixty-seven laryngectomies performed for stage III and stage IV laryngeal carcinoma were reviewed. Stage III disease was managed by surgery alone. Treatment of stage IV disease was divided equally between surgery only and surgery plus radiotherapy. Five-year survival rates by clinical stage were 73% for stage III and 39% for stage IV. Clinical underestimation of disease occurred in 25% of stage III lesions. Unrecognized cartilage invasion and nodal disease occurred with equal frequency. Survival rates computed on the basis of pathologic staging were 91% for stage III and 41% for stage IV. Patients with stage IV disease who were treated with surgery alone had a 28% survival rate, while those receiving both radiotherapy and surgery had a 56% survival rate. In our opinion, surgical pathologic staging more accurately predicts survival than does clinical staging. Surgery alone appears to be adequate therapy for pathologic stage III laryngeal cancer. Addition of radiotherapy significantly improves survival in stage IV disease.

Carcinoma, Squamous Cell↗
PubMed1986

Compression plates in the treatment of advanced anterior floor of mouth carcinoma.

Advanced anterior floor of mouth squamous cell carcinoma has been traditionally treated with wide excision in conjunction with mandibulectomy and radical neck dissection. This has resulted in significant mandibulofacial defects with functional and cosmetic significance. Efforts at primary reconstruction in the past using bone grafts, osteomyocutaneous flaps, and other methods have yielded unsatisfactory results. A history of prior irradiation has made this problem even more refractory. We present a series of 11 patients who underwent composite resection for advanced anterior floor of mouth carcinoma (T2-T4), with primary reconstruction using a dynamic compression plating system in conjunction with local and regional tissue flaps. The clinical courses, complications, and surgical techniques are discussed. The issues of reconstruction at primary treatment, irradiation with a metal plate in the field, and the early restoration of oral function are addressed. Experience in this series shows that compression plates can be an effective method of primary reconstruction for advanced anterior floor of mouth lesions.

Adult↗
PubMed1986

Synchronization of estrus in dairy cows with prostaglandin F2 alpha and estradiol benzoate.

A field study using 322 lactating dairy cows in seven commercial and two university herds was conducted to determine if treatment with estradiol benzoate 40 to 48 h after treatment with prostaglandin F2 alpha would enhance synchronization of estrus. Estrogen treatment tended to increase the proportion of cows in estrus within 5 d (synchronized) after prostaglandin treatment (66.9% versus 58.9%). Of synchronized cows, a greater proportion treated with estrogen (66.9%) were in estrus on d 3 than those not receiving estrogen (48.2%). First service conception rate (31.9%) and interval to second service (35.6 d) were not affected by treatment with estrogen. Milk progesterone was measured in university herds. More cows with milk progesterone concentrations greater than or equal to 8 ng/ml were synchronized (75.4%) than those with less than 8 ng/ml (63.3%). Treatment with estrogen increased synchrony of cows with high progesterone (90.3%) more than prostaglandin alone (60.0%). Based on progesterone concentrations at breeding and 22 to 24 d later, estimated conception rate was 58.7%, and net conception rate based on palpation was 41.3%. Tighter synchrony of estrus can be achieved by using estradiol benzoate 40 to 48 h after prostaglandin. Concentrations of milk progesterone might predict success of treatment.

Animals↗
PubMed1985

External rhinoplasty approach to transsphenoidal hypophysectomy.

The history of transsphenoidal hypophysectomy demonstrates the soundness of the basic concept of approaching the sella turcica in a midline fashion through the nose. Conceptually, it has not been eclipsed since first evolved by Cushing in the early part of this century. The surgical advances since Cushing's time have been major refinements in instrumentation and minor refinements of his basic technique. The external rhinoplasty approach is such a refinement. We have used this technique in a two-year period between June 1982 and June 1984 on 14 patients. We have found this technique for transsphenoidal hypophysectomy to be a simple, reliable, rapid technique for exposing the septum and the floor of the nose. It provides excellent exposure to the sphenoid sinus and pituitary gland without loss of nasal tip projection or other cosmetic deformity.

Adult↗
PubMed1985

Microencapsulation and dissolution properties of a neuroleptic in a biodegradable polymer, poly(d,l-lactide).

Polylactide was polymerized from dilactide under various conditions to yield polymers in the molecular weight range from 11,000 to 21,000 as determined by osmometry. Chlorpromazine was encapsulated by the polylactide polymers by using an emulsification-solvent evaporation method. Microscopic observation revealed that when drug loading was less than or equal to 18%, the drug was in the form of a solid solution in microspheres of polylactide. At higher drug loadings, crystalline drug was present. In vitro dissolution of the encapsulated drug was followed in hydroalcoholic and aqueous buffer media. Studies with the hydroalcoholic media revealed that the drug release rate decreased as microcapsule size increased. However, dissolution in the hydroalcoholic media did not reflect the effect of molecular weight or percentage loading observed in the aqueous system. Dissolution in aqueous buffer showed that t50% increased with molecular weight and that release rates-surface area increased with increasing drug loading.

Antipsychotic Agents↗