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Biomedical subjects

P H Kwon

Publications and source records attributed to P H Kwon.

8 recordsLinked to original sources
PubMed1995

The effects of intra-articular deposition of betamethasone in the goat temporomandibular joint.

PURPOSE: This study evaluated the response of the articular surfaces of the normal goat temporomandibular joint (TMJ) to intra-articular injections of betamethasone suspension. METHODS: Thirty female goats were divided into four experimental groups of seven each and one control group of two animals. The design resulted in 24 joints receiving from one to nine weekly injections of betamethasone suspension, 0.085 mg/kg. The 24 contralateral joints received an identical array of saline injections. In the remaining 12 joints, four were unilaterally injected with saline, four were unilateral uninjected joints, and four were bilateral uninjected joints. All of the joints were inspected grossly and histologically assessed for any intra-articular changes associated with corticosteroid injections. RESULTS: Comparative examination of the gross and histologic features of the injected joints and the eight normal joints showed no significant adverse effects on nondiseased TMJs. CONCLUSION: Intra-articular injection of betamethasone suspension at the dosage and delivery rate used had no harmful effects on the TMJs of nondiseased adult female goats. Because of possible differences between species, these results should not be taken as an indication that betamethasone suspension will not have adverse effects in the human TMJ. These findings support the need for further investigations into the physical and biochemical responses of normal and diseased articular fibrocartilage to different glucocorticosteroids at various concentrations and delivery rates using the goat and other animal models.

Animals↗
PubMed1992

The effect of therapeutic radiation on canine alveolar ridges augmented with hydroxylapatite.

The purpose of this investigation was to evaluate the effect of radiation on hydroxylapatite (HA) implanted subperiosteally for alveolar ridge augmentation in dogs. All bicuspids and molars were extracted from 16 dogs. After 6 weeks, nonporous HA granules were implanted subperiosteally on the alveolar ridge. Following 4 months of healing, 12 dogs (experimental group) underwent therapeutic radiation therapy (Co60, 4,000 rad [40 Gy]) to the head and neck region. Four dogs were not irradiated and served as controls. Four animals (three experimental and one control) were killed at 5,6,7, and 8 months after HA augmentation. Light microscopic evaluation showed that approximately 25% of HA granules were encased by bone while the others were surrounded by fibrous connective tissue. Dissolution of the HA was observed. Microparticles of HA were phagocytized as part of a granulomatous inflammatory reaction. This reaction decreased significantly as time elapsed after implantation. Osteoclastic activity was seen at the junction of HA and periosteum and as part of bone remodeling. Dissolution of the HA granules and the granulomatous inflammatory reaction were not significantly increased by therapeutic radiation. The radiation did not cause development of dehiscence or osteonecrosis.

Alveolar Process↗
PubMed1991

Mucoepidermoid odontogenic cyst.

This unusual cystic lesion was previously described as a lesion that has features of both botryoid odontogenic cyst and mucoepidermoid tumor and later was named as glandular odontogenic cyst. An additional case is reported and its clinicopathologic features described. The name "mucoepidermoid odontogenic cyst" is proposed.

Aged↗
PubMed1990

Triple bone labeling of canine mandibles.

Fluorescence microscopy was used for evaluation of new bone formation in 16 canine mandibles augmented with hydroxylapatite (HA) granules. Three fluorochromes were injected at different time intervals during therapeutic radiation treatment. Oxytetracycline, DCAF, and alizarin-complexone were given intravenously to mark the bone level at these times, respectively. Oxytetracycline, which defined the baseline of bone at implantation of HA, was detectable in 42% of animals that were irradiated and in no animal of the nonirradiated control group. The marker DCAF, designating levels of bone at the start of radiation, was demonstrated in 92% of irradiated animals, and in 75% of animals in the control group. The uptake of alizarin-complexone determined the level of bone found at the end of irradiation. This marker was demonstrated in 50% of the dogs irradiated and in 75% of the control dogs. Bony trabeculae were found between and at the surface of the HA granules. New generation of bone directly on the HA granule and in the surrounding haversian systems as part of normal bone turnover was demonstrated to take place more than 5 months after implantation of HA.

Alveolar Bone Loss↗
PubMed1980

Comparative tolerance of adolescents of differing ethic backgrounds to lactose-containing and lactose-free dairy drinks. I. Initial experience with a double-blind procedure.

A lactose-free (LF) chocolate dairy drink and one containing 4.5% lactose (LC) were administered randomly in 240- and 480-ml volumes on 4 consecutive mornings under double-blind conditions to 110 healthy teenagers (14 to 19 years old) of differing ethnic backgrounds. Capillary blood glucose analysis after 50 g of oral lactose identified 67 of them as lactose malabsorbers. Neither absorbers nor malabsorbers reported significantly different gastrointestinal symptoms after 240 ml of LC compared with the same amount of LF. However, 17 absorbers and 21 malabsorbers reported symptoms inconsistent with intolerance due to lactose. These subjects had symptoms after LF only, after both LF and LC, or after 240 ml but not 480 ml of LC. After 480 ml of LC, 26 malabsorbers had symptoms, compared to 15 after 480 ml of LF. The prevalence of symptoms after 480 ml of LC, but not after 480 ml of LF, was 7% for absorbers, and 24% for malabsorbers. The results indicate that most of the individuals who reported gastrointestinal symptoms after ingestion of the two beverages did so for reasons other than their lactose content.

Adolescent↗
PubMed1980

Comparative tolerance of adolescents of differing ethnic backgrounds to lactose-containing and lactose-free dairy drinks. II. Improvement of a double-blind test.

Using an improved double-blind test procedure, the relationship between lactose malabsorption and lactose intolerance was investigated in 87 healthy teenagers (14--19 years old) of differing ethnic backgrounds. Capillary blood glucose analysis after an oral dose of 50 g of lactose identified 45 lactose malabsorbers. A lactose-free (LF) chocolate dairy drink and one containing 4.5% lactose (LC) were administered under double-blind conditions on 4 consecutive mornings. As in a similar prior study, no statistically significant differences were found in the incidence of symptoms reported by malabsorbers and absorbers after drinking 240 ml of either the LF or the LC preparation. However, 12 lactose absorbers reported symptoms apparently not due to lactose, i.e., after 240 ml of LF, after this amount of both LF and LC, or after 240 ml (but not 480 ml) of LC. Such false-positive results would only be identified by the double-blind approach. It did not appear that any of the malabsorbers had symptoms due to the lactose in 240 ml of LC. However, 16% of the malabsorbers apparently reacted to the lactose in 480 ml of LC. Well designed, double-blind clinical trials are essential for evaluation of gastrointestinal responses to lactose or other ingredients in milk.

Adolescent↗
PubMedDate not supplied

Desmoplastic fibroma of the jaws: surgical management and review of the literature.

Desmoplastic fibroma of the jaws is a rare and locally aggressive tumor that has a high rate of recurrence. The cellularity, extent of the tumor, and completeness of the local excision may be factors in its tendency to recur. We reviewed the literature in an attempt to determine if there was any correlation between the histologic features of a desmoplastic fibroma, or the surgical procedure utilized, and the tumor's recurrence. From the information gathered, it was found that a more cellular desmoplastic fibroma or inadequate surgical procedure may be factors that contribute to the recurrence of the tumor. A case report of desmoplastic fibroma of the mandible in a 9-year-old child is presented. The tumor, which displayed areas of moderate cellularity, was resected via a partial hemimandibulectomy. There has been no recurrence to date (46 months).

Adolescent↗