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Biomedical subjects

J C Price

Publications and source records attributed to J C Price.

At least 91 records · Page 5Linked to original sources
PubMed1985

In vitro modulation of differentiation by calcium in organ cultures of human and murine epithelial tissue.

The differentiation of epithelial tissue in organ cultures of murine buccal mucosa, various human oral mucosa, and human newborn foreskin was found to be dependent on the calcium concentration of the culture media. In low calcium medium (less than or equal to 0.07 mM) epithelial differentiation was inhibited. The original stratifying layers separate and can be removed, producing a destratified explant. Histologically such an explant consists of a dorsal epithelial layer of basal keratinocytes resting on an intact basal lamina with subjacent stroma. At 0.01 mM calcium, the epithelial layer was one to two cells thick whereas at 0.07 mM it could be three or more layers in thickness with the most superficial cells being spread over the underlying cells. In addition to differentiation, keratinocyte migration over the sides of the explant (epiboly) and epithelial proliferation as determined by [3H]thymidine autoradiography were reduced by culture in low calcium medium. Redifferentiation occurs upon return to normal calcium levels (1.8 mM); addition of hydrocortisone to low calcium media was found to facilitate this redifferentiation.

Adult↗
PubMed1985

The pectoralis myocutaneous flap for salvage of necrotic wounds.

The authors have utilized six pectoralis major myocutaneous flaps in attempts to salvage extensive necrotic wounds of the pharynx and neck. The flap was employed in the following situations: massive necrosis of the entire neck skin with both carotid artery systems exposed, radiation necrosis of the neck skin with exposure of carotid artery, dehiscence of gastric pull-up from pharynx with resultant carotid exposure, failed trapezius flap in a radionecrotic oral cavity, and two cases of pharyngocutaneous fistula with extensive soft tissue necrosis. These flaps achieved healing in all cases. One death occurred 3 weeks following complete cutaneous healing secondary to a ruptured carotid pseudoaneurysm. One flap underwent total skin loss but the entirety of the muscle survived and the fistula was successfully closed with the back of the muscle being subsequently skin grafted. One case of dehiscence of the flap from oral mucosa resulted in a minor exposure of mandible with limited osteoradionecrosis controlled by topical means. This flap has performed extremely well in these precarious and difficult situations that previously may not have been salvageable. It has also been effective in abbreviating the required hospitalization and wound care. We conclude that the pectoralis myocutaneous flap should be the primary choice for the management of extensive postsurgical wound necrosis.

Aged↗
PubMed1984

The deltopectoral flap v the pectoralis major myocutaneous flap. Which one?

During the past 2 1/2 years, we have used 21 deltopectoral (DP) and 25 pectoralis major myocutaneous (PM) flaps of which 25 were applied to oral and pharyngeal defects. The concurrent use of both flaps has enabled elucidation of some specific and relative advantages and disadvantages. The following five situations have been identified in which we believe the PM flap is clearly superior: (1) lateral mandibular composite resection defects; (2) large anterior segmental defects; (3) reconstitution of tongue and base of tongue; (4) radionecrosis; and (5) through-and-through defects of skin and oral cavity. The DP flap appears to hold an advantage in the repair of the following defects: (1) limited anterior mandibular loss; (2) posterior and lateral pharyngeal loss; (3) complex resections involving the palate; and (4) cervicofacial skin. The unique advantages of each flap must be weighed against certain disadvantages. Application to each reconstructive problem should be individualized. Proficiency with both flaps enhances the surgeon's ability to deal with major ablative procedures.

Humans↗
PubMed1983

Use of prostaglandin F2 alpha or gonadotropin releasing hormone in treating problem breeding cows.

Ten veterinarians diagnosed and treated 296 cows for reproductive irregularities on 28 dairy farms. Average interval from treatment with 25 mg of prostaglandin F2 alpha (137 cows) to estrus for cows with a corpus luteum (14.6 days) was reduced compared to saline (52 cows) (21.8 days), and a greater percentage (41.6 versus 17.3%) showed estrus within 6 days of treatment. Cows with a cystic corpus luteum (28) were detected in estrus at comparable intervals after prostaglandin F2 alpha or saline (21.8 versus 21.2 days), and similar proportions of cows were detected in estrus within 6 days of treatment (16.7 versus 10.0%). Intervals to estrus among cows with cystic follicles (40 cows) or anestrous cows with follicular ovaries (39 cows) did not differ after treatment with saline or 100 or 200 micrograms of gonadotropin releasing hormone. Within 25 days after treatment, 47.5% of cows with cystic ovaries and 64.1% of anestrous cows showed estrus. Number of cows pregnant after as many as three artificial inseminations of the number examined was 46%, whereas average number of conceptions per service was .32. The long interval from parturition to examination (112 days), the low rate of estrous response after treatment, and the long interval (1.6 estrous cycles) between estruses are consonant with inadequate estrous detection.

Anestrus↗
PubMed1982

Improved and rapid high-performance liquid chromatographic assay for 13-cis-retinoic acid or all-trans-retinoic acid.

A rapid, specific, and sensitive reversed-phase high-performance liquid chromatographic (HPLC) assay for the quantitative determination of all-trans-retinoic acid (I) or 13-cis-retinoic acid (II) in rat serum without extraction of lyophilization is described. Chromatographic separation from retinol, serum components, and retinol acetate standard was achieved on octadecylsilane-coated particles with acetonitrile-1% ammonium acetate as th eluent. Serum samples (100 microliter) containing as little as 10 ng of retinoid were analyzed. Serum level profiles of rats dosed with the retinoids demonstrated the utility of the assay and indicated elimination half-lives of 0.58 and 0.92 hr for I and II, respectively.

Animals↗
PubMed1982

Blood level studies of all-trans- and 13-cis-retinoic acids in rats using different formulations.

Studies to determine the bioavailability of all-trans-retinoic acid from a microencapsulated product were carried out using rats as test animals. The microcapsules were tableted in rat food and individual rats given a tablet containing the equivalent of 10 mg of all-trans-retinoic acid. Comparisons were made with bioavailability data obtained after intravenous and oral administrations of a solution and a suspension. The elimination of all-trans-retinoic acid following intravenous administration of 1- to 5-mg doses occurred by dose-dependent kinetics. The half-lives for the terminal linear portion of the elimination phase after the plateau level were 0.78, 0.74, and 0.93 hr for the 1-, 2.5-, and 5-mg doses, respectively. Based on the doses administered and the relative area under the serum level curves, the all-trans-retinoic acid microcapsules were found to be approximately 34% as bioavailable as the solution dosage form and the microfine suspension 93% as bioavailable. The bioavailability of all-trans-retinoic acid in oral solution was approximately 40% of the intravenous dose. For comparison, rats were also dosed intravenously with 13-cis-retinoic acid, and this compound was found not to follow dose-dependent kinetics at similar dosage levels used for all-trans-retinoic acid.

Animals↗
PubMed1980

Hyperbaric oxygen in the treatment of rhinocerebral mucormycosis.

Hyperbaric oxygen therapy was utilized in a case of fulminant mucormycosis of the maxilla, orbit and temporal bone. The patient had refused radical surgery and death seemed iminent in spite of aggressive medical management of diabetic ketoacidosis, amphotericin B and wide surgical drainage of the maxillary and ethmoid sinuses with orbital decompression. Hyperbaric oxygen was instituted on the following theoretical premises: 1. It would provide oxygenation of tissues distal to occluded arteries, thereby increasing local survival and decreasing acidosis, 2. resultant lessening of acidosis would slow or inhibit rapid growth of the organism, and 3. oxygen in sufficient concentration is fungicidal. The rapid progress of the mucormycosis was arrested. Cultures of tissue prior to hyperbaric oxygen treatment produced heavy growth of Rhizopus, and tissues cultured after therapy grew only bacterial contaminants. The patient survived for 3 mo. only to succumb to Pseudomonas meningitis secondary to necrotic bone and epidural abscess of the middle cranial fossa. Rhinocerebral mucormycosis is a fulminant and frequently fatal disease. No survivors were reported before extensive surgical debridement was utilized. Survival improved to 50% with the addition of amphotericin B. Early diagnosis and correction of underlying acidosis has further improved this to 85%. The response to hyperbaric oxygen in this case report possibly introduces a promising new adjunct to therapy of this serious disease.

Adult↗
PubMed1979

Sublabial approach to the nasal and nasopharyngeal cavities.

A sublabial transnasal degloving approach to the mid-face, nasal cavity, septum, paranasal sinuses, and nasopharynx is described. This approach provides adequate exposure and ample facility for management of tumors in these areas. The pterygomaxillary space and infratemporal fossa ard readily accessible for hemostasis and management of tumor extensions. Children, adolescents, and women with benign and low-grade malignant tumors of these areas are the ideal candidates for this procedure. Twenty-six patients have been managed in this fashion, with no major complication. The cosmetic results have been excellent. This approach to the mid-third of the face, nasal, paranasal, and nasopharyngeal cavities should receive more attention and use.

Adolescent↗
PubMed1978

Endotracheal irradiation of adenoid cystic carcinoma of the trachea.

Management of advanced or recurrent primary tracheal neoplasms has been restricted to palliative external beam irradiation. A patient with recurrent adenoid cystic carcinoma of the trachea was recently treated again by combined external irradiation and endotracheal brachytherapy with iridium 192 sources; the results were dramatic without significant normal tissue toxicity. This endotracheal brachytherapy technique might be applied to tracheal tumors of different histology or more limited extent.

Adult↗
PubMed1977

Drug migration during drying of tablet granulations I: effect of particle size of major diluent.

Migration of a water-soluble drug, propoxyphene hydrochloride, during drying of tablet granulations was studied. Wet granulations of the drug were prepared using lactose as the major diluent and corn starch as a disintegrant. Particle-size fractions of lactose ranging from 53 to 177 micron in diameter were employed in different granulations to examine the effect of particle size of the major diluent on drug migration. Determination of drug concentration at various depths in a dried granulation bed was accomplished by using a drying cell consisting of four layers. A numerical coefficient of migration was developed to compare the extent of drug migration in the various lactose granulations. Migration increased with decreasing particle size of the major diluent, lactose. Two factors that may contribute to increased migration with smaller particles are increased entry suction due to decreased intragranular capillary size and increased intergranular contact area.

Chemistry, Pharmaceutical↗
PubMed1977

Drug migration during drying of tablet granulations II: effect of binder solution viscosity and drying temperature.

The effect of binder solution viscosity and drying temperature on the integranular migration of propoxyphene hydrochloride was studied. Wet granulations containing the drug were prepared using binder solutions with viscosities ranging from 1 to 1000 cps. Temperature studies were conducted using granulations prepared with a 3-cps binder solution and dried at 40, 50, 60, 70, and 80 degrees. Drug migration decreased with increased binder solution viscosity, and insignificant migration occurred in granulations prepared with binder solutions having apparent viscosities above 90 cps. No significant effect on intergranular drug migration was observed within the drying temperature range studied. Tablets compressed from a granulation in which drug migration was high showed a greater tablet-to-tablet drug content variation than a granulation with lower migration, even though each dried granulation was thoroughly mixed before tableting.

Calcium Phosphates↗
PubMed1976

Binding study of tetracyclines to human serum albumin using difference spectrophotometry.

The binding of several tetracyclines to human serum albumin was studied using difference spectrophotometry and a spectrophotometric probe, 2-(4'-hydroxybenzeneazo)benzoic acid. Difference spectra observed for the interaction between the probe and human serum albumin were similar to probe-bovine serum albumin spectra but were less intense for a given concentration of probe and did not reach saturation as quickly. Difference spectra for the tetracyclines were dependent on the characteristics of the ring substituents. More hydrophobic substituents on the D and C rings tended to give more intense difference spectra, but charge-transfer complexing may also have been involved since methacycline with a methylene group in the 6-position showed the most intense spectra of the compounds studied. Solvent perturbation, pH, and urea studies tended to confirm that something other than hydrophobic binding of the tetracyclines was involved. Drug-probe displacement studies showed that methacycline gave the greatest probe displacement followed by doxycycline, chlortetracycline, oxytetracycline, and tetracycline. This order of displacement of the anionic probe indicates that both hydrophobic and charge-transfer binding are involved. Experiments with calcium ion and ethylenediaminetetraacetic acid showed that the difference spectra obtained with the tetracyclines and human serum albumin were not the result of metallic bridge-chelate formation.

Calcium↗
PubMed1976

Clofibrate microcapsules: preparation and release rat studies.

Microencapsulation of clofibrate and dissolution characteristics of clofibrate microcapsules were investigated. Spherical droplets of clofibrate, prepared by a capillary jet method, were encapsulated in gelatin by simpel coacervation, using sodium sulfate as the coacervating agent. The microcapsules, which were hardened up to 8 hr with formaldehyde, were recovered as discrete, free-flowing particles. Dissolution of clofibrate from the microcapsules was not adequately described by either square root of time or Langenbucher kinetics but followed predominantly zero-order release patterns at all hardening times. A linear correlation was found between the hardening times and the t50% release time.

Capsules↗
PubMed1975

Binding study of sulfonylureas and phenothiazines to bovine serum albumin using difference spectrophotometry.

2-(4'-Hydroxybenzeneazo)benzoic acid is a spectrophotometric probe which shows absorption spectrum changes upon binding to protein. Difference absorption spectra of this probe were used as an indirect measurement of the binding of selected sulfonylurea and phenothiazine drugs to bovine serum albumin. The results obtained using the spectrophotometric probe were similar to data obtained from other methods, especially fluorescent methods. Of the four sulfonylureas studied, tolbutamide showed the highest binding affinity, followed by glyburide, glipizide, and acetohexamide, in that order. The data collected for phenothiazine drugs indicated that chlorpromazine has the highest affinity, followed in order by trifluoperazine, perphenazine, fluphenazine, and promazine. Correlation of these results with chemical composition indicated that the interaction of phenothiazine drugs with bovine serum albumin was of a hydrophobic nature.

Animals↗