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Biomedical subjects

Y R Chen

Publications and source records attributed to Y R Chen.

At least 19 recordsLinked to original sources
PubMed1992

Facial midline and symmetry: modified face bow.

A facial "cone" can be drawn inside the head. The apex of the cone is the midpoint of the line that connects both ear canals, point C, and the face is the base. A modified face bow is designed with holes through which a Steinmann pin is passed, meeting at the apex of the facial cone. After the ear bolts are symmetrically fixed, the Steinmann pin through the central hole follows the midline of the face as the bow rotates from the forehead to the chin. The right and left facial bony protrusions can be evaluated by two Steinmann pins projecting through the corresponding holes on the face bow. This device is utilized to determine the facial midline and facial symmetry during surgery. It also can be used as a tool for anthropologic studies.

Equipment Design↗
PubMed1992

A simple and effective method of compression dressing for skin grafts.

Skin grafting is one of the most common procedures in plastic and reconstructive surgery. Various methods of fixation and dressing, to achieve good approximation and immobilization of skin grafts and, thus, to bring about better graft survival, are described. A simple method utilizing readily available latex and staples provides good fixation and compression. This technique has been applied in 50 patients requiring skin grafts. The morbidity and complications were minimal, and the grafts have taken satisfactorily. Pressure study with an animal model has revealed adequate compression.

Animals↗
PubMed1991

The human DNA-activated protein kinase phosphorylates simian virus 40 T antigen at amino- and carboxy-terminal sites.

Protein phosphorylation modulates the functions of simian virus 40 large T antigen (TAg) in productive and transforming infections. We recently described a DNA-activated protein kinase (DNA-PK) that efficiently phosphorylates TAg and several other nuclear, DNA-binding proteins in vitro (S.P. Lees-Miller, Y.-R. Chen, and C. W. Anderson, Mol. Cell. Biol. 10:6472-6481, 1990). In this report, we show by direct amino acid sequence analysis that DNA-PK phosphorylates TAg strongly at Ser-677, a residue known to be important for TAg interaction with origin site I and for transformation. We propose that DNA-PK may modulate the role of TAg in repressing early viral transcription and cell transformation, but a role for DNA-PK in regulating simian virus 40 DNA synthesis is not excluded. DNA-PK also phosphorylates Ser-665, and Ser-667, and one or more serines between amino acids 110 and 131. At least six serines, Ser-111, Ser-112, Ser-120, Ser-665, Ser-667, and Ser-677, are phosphorylated in TAg purified from baculovirus vector-infected insect cells.

Amino Acid Sequence↗
PubMed1990

Mandibular fractures in children-immediate reduction and fixation with orthodontic resin.

Mandibular fractures are not common in children. In Chang Gung Memorial Hospital from 1983 to 1987, we had 354 mandibular fractures but only 12 cases happened to children under 10 years old. Mandibular fractures in children under 10 years cannot be treated in the same way as patient with permanent teeth since possibly neither intermaxillary, nor interosseous fixation can be applied. Complication have been observed in 3 (25%) of these 12 patients, including malocclusion, infection and open bite. In 1988, orthodontic resin was adopted as the fixation material after immediate reduction in three cases. There is no complication and the patients have had a better postinjury quality of life compared with those patients treated from 1983 to 1987. The importance of immediate reduction for mandibular fracture in children and the application of resin cap splint are stressed.

Child↗
PubMed1990

[Voice disorders in children with velopharyngeal valving problems].

The purpose of this study was to examine if velopharyngeal valving problem can affect voice production (phonation) to some extent. Seventeen cleft palate children, mean age 7.0 had developed hoarseness for years without any treatment. In this study, each subject received a complete voice evaluation and the velopharyngeal (VP) function assessment. Voice evaluation included vocal cords condition and four voice parameters (quality, intensity, fundamental frequency and phonation behaviors). V-P function, classified into 3 levels (adequate, marginal & inadequate), was based on speech evaluation and instrumentations. The results showed that 41% of the subject had had bilateral vocal nodules; phonation indicated various findings in four parameters. V-P function indicated 83% of the subjects had valving problems, among which 71% had marginal V-P level. The results lead to discussion that V-P valving problems may be related with phonation disorders, because subjects like to use "compensatory behaviors" to mask their speech disorders. Among the level of valving problems, a marginal V-P function may achieve an appropriate V-P valving under compensatory behaviors and results in phonation disorders. The authors further suggest that subjects with V-P valving problems should not be subjected to the stresses of speech therapy for hypernasality because of the chance that they would compensate laryngeally for V-P problems. Meanwhile, the treatment for nodules or voice disorders should eliminate compensatory behaviors, then secondary management such as pharyngeal flap surgery for V-P problem should be considered if voice disorders persist.

Child↗
PubMed1990

Facial bone fracture associated with carotid-cavernous sinus fistula.

Out of 989 cases of facial bone fracture, ten patients had carotid-cavernous sinus fistulas (1.01%). Their ages ranged from 25 to 48 years. Seven were male and three female. Two of the ten patients had lower third, three patients had middle third, three patients had upper third, and two patients had combined middle and lower third facial bone fractures. The signs and symptoms of a fistula appeared from the first postinjury day up to 50 days after the injury (mean, 21 days). Four patients had symptoms after operation for facial bone fracture. Most fistulae were identified by arteriography before treatment. Followup ranged from 1 year, 8 months, to 5 years, 9 months (mean, 2 years, 9 months). One patient had a malocclusion. Nine patients had complete resolution of their bruits. Complications included unilateral complete visual loss (two), CSF rhinorrhea (two), and stroke in one of the two CSF rhinorrhea patients. One patient expired due to a severe head injury, and there was one death from an unrelated cause.

Adult↗
PubMed1990

Human cells contain a DNA-activated protein kinase that phosphorylates simian virus 40 T antigen, mouse p53, and the human Ku autoantigen.

HeLa cells contain a serine/threonine protein kinase (DNA-PK) that is strongly activated in vitro by low concentrations of double-stranded DNA (dsDNA). Activation was specific for dsDNA; both natural DNAs and synthetic oligonucleotides functioned as kinase activators. The fact that DNA-PK activity was rapidly inhibited by incubation with dsDNA and ATP suggests that DNA-PK activity also may be regulated by autophosphorylation. During gel filtration, DNA-PK activity behaved as a 350-kDa protein, and highly purified DNA-PK contained a dsDNA-binding, 350-kDa polypeptide that was phosphorylated in a dsDNA-dependent manner. We conclude that this 350-kDa polypeptide is likely to be DNA-PK. Previously we showed that the dsDNA-activated kinase phosphorylates two threonines at the N terminus of hsp90 alpha (S. P. Lees-Miller and C. W. Anderson, J. Biol. Chem. 264:17275-17280, 1989). Here we show that DNA-PK also phosphorylates the simian virus 40 large tumor antigen, the mouse tumor-suppressor protein p53, the human Ku autoantigen, and two unidentified HeLa DNA-associated polypeptides of 52 and 110 kDa. Identification of these and other newly identified DNA-binding substrates suggest that the dsDNA-activated kinase may regulate transcription, DNA replication, or cell growth.

Amino Acid Sequence↗
PubMed1990

Active oxygen radicals produced by leukocytes of malignant lymphoma.

The electron spin resonance (ESR) spectra of active oxygen radicals produced during the respiratory burst of PMA-stimulated leukocytes and oxygen consumption are studied by ESR spin trapping and spin probe oxymetry for 31 times in 17 cases of malignant lymphoma. The results showed that the spectra produced from PMA-stimulated patients' leukocytes were predominantly spin adducts of DMPO-hydroxyl radicals (DMPO-OH). The decrease in oxygen consumption during respiratory burst suggested that respiratory burst function was inhibited. Kinetic observations of patient condition showed that respiratory burst and oxygen consumption were improved and even approached normal, when the patient was in remission or the condition was ameliorated. This paper is the first of its type and helps clarify the mechanism of malignant proliferation and metastasis.

Adult↗
PubMed1990

Treatment of craniomaxillofacial fibrous dysplasia: how early and how extensive?

Twenty-eight craniomaxillofacial fibrous dysplasia patients were treated as early as the symptoms occurred. The principles of surgical treatment were based on the zones of involvement: total excision of dysplastic bone of fronto-orbital, zygoma, and upper maxillary origin (zone 1) and bone reconstruction primarily; conservative excision on hair-bearing skull (zone 2), central cranial base (zone 3), and tooth-bearing bones (zone 4); and optic canal decompression on patients with orbital dysplasia and decreasing visual acuity. Patients were followed for 1 to 11 years (average 5.3 years). No recurrence or invasion of the fibrous dysplasia into the grafted bone was seen. One patient had orthognathic maxillary osteotomy on the reconstructed maxilla 6 years after initial reconstruction. Five of 19 patients with alveolar dysplasia had a recurrence and were reshaped. One patient had mandibular sagittal osteotomies to set back the prognathic, fibrous dysplasic mandible after three attempts at conservative shaving. Another patient with mandibular fibrous dysplasia had recurrence with pain and a hemimandibulectomy with successful immediate free vascularized iliac bone graft reconstruction.

Adolescent↗
PubMed1990

Traumatic eyelid invagination: case reports.

Three rare cases of upper eyelid trauma are presented. In high-speed traffic accidents, the upper eyelids were penetrated by glass, avulsed, and then, together with pieces of glass, pushed over the globe and buried deeply in the retrobulbar area. The invaginated eyelids were pulled out gently, the conjunctiva still attached to the globes. They were repaired primarily. In these patients eyelid function and cosmesis were preserved.

Accidents, Traffic↗
PubMed1989

[Cleft lip and cleft palate in the Craniofacial Center, Chang Gung Memorial Hospital: incidence, sex, seasonality and topographic distribution].

Of 2963 patients registered at the Chang Gung Craniofacial Center, 1755 patients (906 males and 849 females) who did not have any previous surgery were carefully delineated according to cleft side, involvement of primary or secondary palate and severity of cleft. Cleft lip and palate (43.88%) was the most common cleft, cleft palate (30.88%) the second, while cleft lip (25.24%) the least. More males were found in cleft lip group or cleft lip and palate group, and more females in the cleft palate group. Regarding clefts involving both primary and secondary palates, the cleft of both palates was usually complete, but when the clefts involved either the primary or secondary palate, the cleft was usually incomplete. With regards to the laterality of unilateral cleft lip and/or palate, the left side was affected more than right side. With regard to seasonal variation, cleft palate patients showed the highest incidence from August to October and the lowest incidence from November to January. Cleft lip or cleft lip and palate patients showed the highest incidence from November to February but no obvious difference in the rest of the months. Topographic distribution disclosed that more patients were domiciled in the area north to Hsien-Chu, especially the urban Taipei area.

Adolescent↗
PubMed1989

Facial elephantiasis neurofibromatosa--excision and skin graft.

A case of left facial elephantiasis neurofibromatosa was treated with near-total excision and skin graft. Results were favorable. Repositioning of canthal ligaments, preserving part of relatively normal masseter muscle and primary nasal reconstruction with forehead flap were performed. The skin graft over the myxomatous muscle was successful. Troublesome bleeding was avoided or controlled by incising the normal skin, subperiosteal dissection, hypotensive anesthesia, and chromic catgut suture ligature.

Adult↗
PubMed1989

[Anatomic observation and clinical significance of vertebral pedicle].

To be aware of the security in fixing the spine through posterior approach with instrumentation, a study of the regional anatomy of the pedicle was done by measuring various parameters in 51 thoraco-lumbar (T-9 to L-3) specimens, including the thickness, height, and length of pedicle, the angles made by line of the pedicle axis with both the sagittal and longitudinal lines of the same vertebral body, and the distance between pedicles of each vertebra. The space between spinal cord and pedicles on cross section of 35 cadaveral specimens was also measured. For purpose of comparison to find out the anatomical significance for clinical application, measurement of corresponding parameters on CT scan films of 50 cases were carried out. Taking into account of all these parameters, findings and some clinical experience, detailed discussion about operative indications, procedures of internal fixation and the inserting point along with the direction of drilling screws in were made.

Anthropometry↗
PubMed1989

Duplication of stomatodeal structures: report of three cases with literature review and suggestion for classification.

Three cases of duplications of stomatodeal structures are reported. One had an accessory mouth that could move simultaneously with his mouth at sternal notch. Another had a teeth-bearing bony mass at left maxilla with excessive upper lip and a false pouch. The third had an excessive upper lip, upper jaw with teeth, and hard and soft palate. The literature is reviewed, and a classification is suggested: type I, a duplicated mouth; type II, duplication of maxilla-upper lip or mandible-lower lip complex; and type III, centrally located, poorly developed lip-jaw duplication.

Abnormalities, Multiple↗