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Biomedical subjects

R Y Tsai

Publications and source records attributed to R Y Tsai.

16 recordsLinked to original sources
PubMed2001

Experience of tumescent liposuction in the treatment of osmidrosis.

BACKGROUND: Tumescent liposuction is a safe procedure for removal of subcutaneous fat tissue. Because apocrine glands are located deep in the fat, surgical removal of these glands by nontumescent liposuction has been utilized for treating osmidrosis. OBJECTIVE: To evaluate the effect of tumescent liposuction in the treatment of osmidrosis and to compare the efficacy of simple tumescent liposuction and combined tumescent liposuction and curettage. METHODS: A total of 20 patients with osmidrosis (all female, age 16-44 years) were included in this study. Ten patients were treated by simple tumescent liposuction, the other 10 patients were treated by tumescent liposuction combined with curettage. The aspirates were sent for pathologic examination. At a follow-up visit, the improvement of symptoms was graded by the patient as satisfied when the odor decreased> 75%, partially satisfied when it decreased >/=50% to </=75%, and dissatisfied when it decreased <50%. RESULTS: Among the 10 patients treated with simple tumescent liposuction, 10% were satisfied, 70% were partially satisfied, and 20% were dissatisfied. Eighty percent of patients treated with a combination of tumescent liposuction and curettage were satisfied, while 20% were partially satisfied. No major complications were noted following the procedure except mild ecchymosis and swelling. CONCLUSION: Tumescent liposuction is a simple and safe procedure in the treatment of osmidrosis. Tumescent liposuction combined with curettage is better than simple tumescent liposuction alone. The effect of tumescent liposuction combined with curettage in the treatment of osmidrosis is compatible with traditional surgery or neurosurgery but offers fewer complications.

Adolescent↗
PubMed2000

Cell contact regulates fate choice by cortical stem cells.

Cell fate is determined by intrinsic programs and external cues, such as soluble signals and cell-cell contact. Previous studies have demonstrated the roles of soluble factors in the proliferation and differentiation of cortical stem cells and cell-cell contact in maintaining stem cells in a proliferative state. In the present study, we focused on the effect of cell-cell interaction on cell-fate determination. We found that density could exert a strong influence on the cell-type composition when cortical stem cells differentiate. Multipotent stem cells, which normally gave rise to neurons, astrocytes, and oligodendrocytes under high-density culture condition, differentiated almost exclusively into smooth muscle at low density. Clonal analysis indicated that smooth muscle and astrocytes were derived from a common precursor and that the density effect on cell types used an instructive mechanism on the choice of fate rather than an effect of selective survival and/or proliferation. This instructive mechanism depended on the local and not the average density of the cells. This local signal could be mimicked by membrane extract. These findings demonstrate the importance of membrane-bound signals in specifying lineage and provide the first evidence for a short-range regulatory mechanism in cortical stem cell differentiation.

Animals↗
PubMed2000

Nitric oxide modulates the development and surgical reversal of renovascular hypertension in rats.

OBJECTIVE: To evaluate the role of nitric oxide (NO) in the development and unclipping-induced reversal of blood pressure and bilateral renal function in two-kidney, one clip (2K1C) Goldblatt hypertensive rats. METHODS: Goldblatt hypertensive rats were prepared by clipping the left renal artery 4 weeks before unclipping experiments. NG-nitro-L-arginine methyl ester (L-NAME) was administered after clipping and during unclipping to inhibit nitric oxide (NO) synthesis. Blood pressure and bilateral renal responses were measured. RESULTS: Chronic L-NAME treatment accelerated and aggravated blood pressure elevations and increased plasma nitrite and nitrate levels in 2K1C rats. Surgical removal of the renal artery clip induced profound reductions in blood pressure in rats with and without L-NAME treatment. However, the magnitude of the unclipping-induced depressor response at the first post-unclipping hour was significantly smaller in L-NAME-treated rats compared to those without L-NAME administration (15 +/- 1 versus 22 +/- 1%, P < 0.05). Two hours after unclipping, blood pressure of both groups fell to a comparable, normal level. Acute intravenous infusion of L-NAME in established 2K1C hypertensive rats further increased blood pressure. Subsequent unclipping caused a depressor response similar to that observed in hypertensive rats treated chronically with L-NAME. Despite the marked decreases in blood pressure, unclipping induced striking increases in glomerular filtration rate (GFR), urine flow and sodium and potassium excretion rates in the ipsilateral kidney. However, the magnitudes of increases in GFR and the diuretic and natriuretic responses in rats without L-NAME treatment were significantly greater than in rats with L-NAME administration. In contrast, unclipping reduced these function indices in the contralateral kidney to a similar level in rats with and without L-NAME treatment. CONCLUSIONS: NO exerts vasodilator action and thereby lessens renal artery clipping-induced blood pressure elevation. Furthermore, unclipping-induced release of NO partially contributes to the early reduction in blood pressure and changes in bilateral renal function but does not directly mediate the normalization of blood pressure after unclipping in this hypertension model.

Animals↗
PubMed1999

Subcutaneous leiomyosarcoma on the face.

BACKGROUND: Cutaneous leiomyosarcoma is a rare soft tissue sarcoma with a predilection for the lower extremities. Leiomyosarcoma of the face is very rare. Subcutaneous leiomyosarcoma has a higher likelihood of recurrence and metastases than that of the superficial dermal type. OBJECTIVE: The dermatologic surgeon and pathologist should be familiar with the characters of subcutaneous leiomyosarcoma. METHODS: We report a case of subcutaneous leiomyosarcoma on the face with the results of histologic examination and immunohistochemical studies. RESULTS: Leiomyosarcoma of the face is exceedingly rare. The deep subcutaneous type is thought to arise from the smooth muscle of the vascular wall. The neoplasm we report here has deep tumor invasion, high malignancy grade (3B), and large tumor size. Wide excision and postoperative radiotherapy were performed. CONCLUSION: Subcutaneous leiomyosarcoma has a higher likelihood of recurrence and metastases than that of the superficial dermal type. The most effective treatment is wide excision with 3-5 cm lateral margins and a depth that includes subcutaneous tissue and fascia.

Facial Neoplasms↗
PubMed1998

Evaluation of blood loss during tumescent liposuction in Orientals.

BACKGROUND: There are high risks from general anesthesia and excessive bleeding associated with traditional liposuction using the dry or wet method. The blood loss has been estimated to be between 15% and 45%. The tumescent technique permits liposuction of more than 3,000 ml of fat totally by local anesthesia without sedation. The blood loss is reported to be less than 1% of aspirate. OBJECTIVE: To examine the blood loss during liposuction using tumescent technique in Chinese patients compared with that of Caucasians as published in the literature. METHODS: Hemoglobin values of patient's preoperative venous blood and infranatant of aspirate were measured in 45 consecutive cases of liposuction using the tumescent technique from May 1996 to June 1997. RESULTS: A total of 30 patients completed the study. The average blood loss was estimated to be 1.08% of aspirate. CONCLUSION: From this study, we found the blood loss in Chinese patients is comparable with that in Caucasians. Tumescent liposuction is a safe dermatologic cosmetic surgical procedure without the need of blood transfusion and general anesthesia.

Adult↗
PubMed1998

Experience with laser hair transplantation in Orientals.

BACKGROUND: The advent of high-energy carbon dioxide (CO2) laser-assisted hair transplantation in recent years provides a new recipient area technique for hair restoration surgery. It offers the advantages of less bleeding, time consumption, and graft compression. Specific laser parameters have been recommended in Caucasian but not Oriental patients. OBJECTIVE: To determine the effectiveness as well as appropriate parameters of laser hair transplantation in Oriental patients. METHODS: A Sharplan SilkTouch laser with the Flashscanner set to produce a 0.8-1-mm recipient site hole was employed for all subjects. Various CO2 laser parameters were used to compare the graft survival rate with traditional Nokor needle or microdilator methods for micrografting on each side of the scalp. A total of 20 patients joined the study in the past 18 months. A skin biopsy was performed to examine the tissue effect of the different laser parameters. RESULTS: Hair survival was less than that seen with conventional micrografting techniques in the first five cases, in whom CO2 laser parameters of 36-40 W and 0.2-0.7 seconds were used. After adjusting the parameters to 55 W and 0.1-0.15 seconds, the survival rate increased to between 80% and 90%. In addition, most patients thought the laser-prepared sites resulted in a more natural appearance and better hair density, when they were compared with conventionally prepared sites. CONCLUSIONS: From our study, we find that CO2 laser parameters of 55 W and 0.1-0.15 seconds seem to be the appropriate parameters for Oriental hair transplant patients. Further studies are required to establish laser parameters that will produce better hair survival.

Alopecia↗
PubMed1998

Identification of DNA recognition sequences and protein interaction domains of the multiple-Zn-finger protein Roaz.

Roaz, a rat C2H2 zinc finger protein, plays a role in the regulation of olfactory neuronal differentiation through its interaction with the Olf-1/EBF transcription factor family. An additional role for the Roaz/Olf-1/EBF heterodimeric protein is suggested by its ability to regulate gene activation at a distinct promoter lacking Olf-1/EBF-binding sites. Using an in vitro binding-site selection assay (Selex), we demonstrate that Roaz protein binds to novel inverted perfect or imperfect repeats of GCACCC separated by 2 bp. We show that Roaz is capable of binding to a canonical consensus recognition sequence with high affinity (Kd = 3 nM). Analysis of the structural requirement for protein dimerization and DNA binding by Roaz reveals the role of specific zinc finger motifs in the Roaz protein for homodimerization and heterodimerization with the Olf-1/EBF transcription factor. The DNA-binding domain of Roaz is mapped to the N-terminal 277 amino acids, containing the first seven zinc finger motifs, which confers weak monomeric binding to a single half site and a stronger dimeric binding to the inverted repeat in a binding-site-dependent manner. Full-length protein can form dimers on both the inverted repeat and direct repeat but not on a single half site. These findings support the role of the TFIIIA-type Zn fingers in both protein-protein interaction and protein-DNA interaction and suggest distinct functions for specific motifs in proteins with a large number of zinc finger structures.

Amino Acid Sequence↗
PubMed1998

Nitric oxide synthesis inhibition retards surgical reversal of one-kidney Goldblatt hypertension in rats.

Surgical correction of renal artery stenosis in Goldblatt hypertension rapidly normalizes blood pressure and increases renal function. This study was conducted in 1-kidney, 1 clip (1K1C) Goldblatt hypertensive rats to examine whether the unclipping-induced reversal of blood pressure and renal function is mediated by nitric oxide (NO). The 1K1C rats were prepared and given tap water with or without supplementation of NG-nitro-L-arginine methyl ester (L-NAME). Systolic blood pressure (SBP) before and after renal artery clipping was measured with the tail-cuff method. Four weeks later, surgical unclipping was performed while blood pressure and renal function responses were determined. The results show that clipping the renal artery for 4 weeks increased SBP from 140+/-5 to 183+/-6 mm Hg (P<0.05). Concurrent L-NAME treatment accelerated and aggravated the clipping-induced increases in SBP from 138+/-6 to 219+/-8 mm Hg (P<0.05). Surgical unclipping reduced blood pressure to normotensive levels within 2 hours in all hypertensive rats with and without chronic or acute L-NAME treatment. However, the magnitude of reductions in blood pressure in the initial 1 hour after unclipping was significantly less in L-NAME-treated rats than in nontreated rats (9+/-2% versus 16+/-1%, P<0.05). Despite reducing blood pressure, unclipping significantly increased glomerular filtration rate, urine flow, and sodium and potassium excretions, but the extent of the increases in these renal functions was significantly attenuated in L-NAME-treated rats. These data suggest that NO production partly contributes to the hypotensive and renal responses to unclipping but does not mediate the reversal of renovascular hypertension of this model.

Animals↗
PubMed1998

Microscopic laminotomies for degenerative lumbar spinal stenosis.

In this retrospective study, we investigated 50 patients who had undergone primary lumbar microsurgical multiple laminotomy without spinal fusion for degenerative spinal stenosis. There were 31 men and 19 women with a median age of 66 years (35-85 years). Thirteen patients had grade I spondylolisthesis, most at L4-L5 levels (11 of 13). Single-level laminotomy was done in 13 patients, two levels in 30, and three levels in 7. The median follow-up period was 27 months (range, 15-48 months). A standardized self-reported questionnaire was used for clinical outcome study. The demographic data and clinical features of these patients were analyzed for the prognostic factors. The analysis showed excellent results in 18 patients, good in 16, fair in 8, and poor in 8, whereas 30 patients reported that they were very satisfied with the surgery results, 10 were somewhat satisfied, 2 were somewhat dissatisfied, and 8 were very dissatisfied. Therefore, the satisfactory rate of the surgery was higher if judged by patient satisfaction. Among the parameters analyzed, the presence of neurogenic claudication (p = 0.008), coexisting disease (p = 0.04), and the absence of motor deficit (p = 0.03) were associated with lower total scores. In addition, longer duration of symptoms (p = 0.04) was associated with less improvement of back pain score, whereas the absence of motor deficit (p = 0.004) was associated with less improvement of leg pain score. The presence of spondylolisthesis did not affect outcomes.

Adult↗
PubMed1997

Intraoperative dermatomal evoked potential monitoring fails to predict outcome from lumbar decompression surgery.

STUDY DESIGN: Thirty-three patients with single-level, unilateral lumbosacral radiculopathy underwent micro-decompression and intraoperative dermatomal evoked potential monitoring. Side-to-side latency asymmetry was calculated. A criteria for "abnormal" was defined. Intraoperative dermatomal evoked potentials were obtained before and after decompression. The changes were correlated with clinical outcome at the 3-month follow-up examination. OBJECTIVES: To determine whether intraoperative dermatomal evoked potential latency asymmetry confirms nerve root compression and whether an improvement of latency asymmetry after decompression predicts a good clinical outcome. SUMMARY OF BACKGROUND DATA: Intraoperative dermatomal evoked potential has been proposed as a test to assess the adequacy of nerve root decompression. Initial reports suggested improvement of dermatomal evoked potential amplitude and latency after decompression. The clinical efficacy is controversial because of its technical difficulty and inherent variation. METHODS: Cervical recording was chosen to reduce the effects of anesthesia. The asymptomatic nerve root was used as a control. Quality of the tracings was determined by evoked potentials-to-noise amplitude ratio. Clinical outcome was based on patient's pain relief and satisfaction. RESULTS: Tracings of acceptable quality were obtained at baseline in 57.6% (19 of 33) of patients. A side-to-side latency asymmetry > 5% was defined as abnormal. Before decompression, 68.4% (13 of 19) of patients had an abnormal dermatomal evoked potential. After decompression, latency asymmetry returned to normal in every patient. Clinical outcome was good or excellent in 13 patients, fair in four patients, and poor in two patients. Dermatomal evoked potential latency improvements were not related to variation in clinical outcome. CONCLUSIONS: Intraoperative dermatomal evoked potential monitoring is technically demanding. Finding reproducible potentials is difficult. More research is necessary before general use of dermatomal evoked potentials for monitoring nerve root decompression.

Adult↗
PubMed1997

The characterization of the Olf-1/EBF-like HLH transcription factor family: implications in olfactory gene regulation and neuronal development.

The Olf-1/EBF helix-loop-helix (HLH) transcription factor has been implicated in olfactory gene regulation and in B-cell development. Using homology screening methods, we identified two additional Olf-1/EBF-like cDNAs from a mouse embryonic cDNA library. The Olf-1/EBF-like (O/E) proteins O/E-1, O/E-2, and O/E-3 define a family of transcription factors that share structural similarities and biochemical activities. Although these O/E genes are expressed within olfactory epithelium in an identical pattern, they exhibit different patterns of expression in the developing nervous system. Although O/E-1 mRNA is present in several tissues in addition to olfactory neurons and developing B-cells, O/E-2 and O/E-3 are expressed at high levels only in olfactory tissue. In O/E-1 knock-out animals, the presence of two additional O/E family members in olfactory neurons may provide redundancy and allow normal olfactory neurodevelopment. Further, the identification of the O/E family of HLH transcription factors and their embryonic expression patterns suggest that the O/E proteins may have a more general function in neuronal development.

Age Factors↗
PubMed1997

Cloning and functional characterization of Roaz, a zinc finger protein that interacts with O/E-1 to regulate gene expression: implications for olfactory neuronal development.

We have identified a protein, Rat O/E-1-associated zinc finger protein (Roaz), that plays a role in regulating the temporal and spatial pattern of olfactory neuronal-specific gene expression. This protein functions by interacting with the olfactory factor O/E-1 and modulating its transcriptional activity. Roaz, isolated via a yeast two-hybrid screen, encoded a protein containing 29 C2H2 zinc fingers of the TFIIIA type. The Roaz mRNA was found in brain, eye, olfactory epithelium, spleen, and heart. In situ hybridization data indicated that Roaz was expressed in the basal layer, consisting of neural precursor cells and immature sensory neurons of the olfactory epithelium, but not in the mature receptor cells. We showed that the Roaz protein bound specifically to O/E-1 by using the yeast two-hybrid system. The two proteins formed a stable complex in coimmunoprecipitation and in vitro binding assays. Introduction of Roaz and O/E-1 into cells containing an olfactory promoter-driven luciferase reporter demonstrated that Roaz abolished O/E-1-mediated transcriptional activation. We propose that the function of Roaz is to modulate negatively the transactivational activity of O/E-1 and to act as a switch protein in the coordination of olfactory sensory neuron differentiation.

Amino Acid Sequence↗
PubMed1995

Aluminum oxide crystal microdermabrasion. A new technique for treating facial scarring.

BACKGROUND: Aluminum oxide crystal microdermabrasion, a newly developed technique, has the advantages of less bleeding, fewer complications, better compliance, and no need for local anesthesia or high surgical skill in comparison with traditional dermabrasion. OBJECTIVE: To demonstrate the effectiveness of this new technique in the treatment of facial scarring. METHODS: A total of 41 patients were treated by this technique during the past 2 years (July 1992 to June 1994). RESULTS: All patients treated had good to excellent clinical improvement with 9.10 mean treatment sessions. CONCLUSION: From our experience and results, we think aluminum oxide crystal microdermabrasion is a safe surgical procedure and will be a good supplement to traditional dermabrasion especially in this era of HIV infection.

Acne Vulgaris↗
PubMed1993

Genes encoding components of the olfactory signal transduction cascade contain a DNA binding site that may direct neuronal expression.

Genes which mediate odorant signal transduction are expressed at high levels in neurons of the olfactory epithelium. The molecular mechanism governing the restricted expression of these genes likely involves tissue-specific DNA binding proteins which coordinately activate transcription through sequence-specific interactions with olfactory promoter regions. We have identified binding sites for the olfactory neuron-specific transcription factor, Olf-1, in the sequences surrounding the transcriptional initiation site of five olfactory neuron-specific genes. The Olf-1 binding sites described define the consensus sequence YTCCCYRGGGAR. In addition, we have identified a second binding site, the U site, in the olfactory cyclic nucleotide gated channel and type III cyclase promoters, which binds factors present in all tissue examined. These experiments support a model in which expression of Olf-1 in the sensory neurons coordinately activates a set of olfactory neuron-specific genes. Furthermore, expression of a subset of these genes may be modulated by additional binding factors.

Adenylyl Cyclases↗