PubMed Health⌕ Search

Biomedical subjects

K K Li

Publications and source records attributed to K K Li.

At least 19 recordsLinked to original sources
PubMed2004

Improved measurement of the K+-->pi+nunu; branching ratio.

An additional event near the upper kinematic limit for K+-->pi(+)nunu; has been observed by experiment E949 at Brookhaven National Laboratory. Combining previously reported and new data, the branching ratio is B(K+-->pi(+)nunu;)=(1.47(+1.30)(-0.89))x10(-10) based on three events observed in the pion momentum region 211<P<229 MeV/c. At the measured central value of the branching ratio, the additional event had a signal-to-background ratio of 0.9.

Journal Article↗
PubMed2004

Case selection in macular relocation surgery for age related macular degeneration.

BACKGROUND: To date there has been no randomised controlled trial demonstrating the safety and efficacy of macular relocation surgery (MRS) for age related macular degeneration (AMD). Vision can be improved in some patients and made worse in others despite successful surgery or because of complications. PURPOSE: To determine which patients would benefit from MRS. METHODS: Twenty nine patients with exudative AMD took part in a prospective, non-comparative, interventional study. Macular relocation surgery involved phacoemulsification, vitrectomy, 360 degrees retinotomy, excision of choroidal neovascular membrane, and macular relocation using an infusion of 5-fluorouracil and low molecular weight heparin as adjuvant to prevent proliferative vitreoretinopathy. Patients underwent protocol refraction preoperatively and six-monthly postoperatively by designated optometrists. Preoperative fundus fluorescein angiograms were read by masked observers and the lesions were classified according to a set protocol. The main outcome measures were visual improvement, final vision of better than 20/400, reading speed, critical print size. Logistic and multiple stepwise linear regressions were used to identify independent factors which predicted the main outcomes. RESULTS: Preoperative visual acuity (20/120 or worse) and lesion type (predominantly classic or submacular haemorrhage) were significantly associated with visual improvement (coefficient of regression B = 26.8, p<0.001 and B = 14.9 with p = 0.045 respectively). There were no significant independent factors which predicted a final distance logMAR visual acuity of 1.3 (20/400) or any arbitrary definition of blindness. CONCLUSIONS: The study showed that it was possible to select cases that were more likely to experience an improvement in vision following MRS.

Aged↗
PubMed2002

Further evidence for the decay K+ -->pi+nu(nu).

Additional evidence for the rare kaon decay K+-->pi+nu(nu) has been found in a new data set with comparable sensitivity to the previously reported result. One new event was observed in the pion momentum region examined, 211 pi+nu(nu)) = 1.57(+1.75)(-0.82)x10(-10).

Journal Article↗
PubMed2001

Patient's perception of the facial appearance after maxillomandibular advancement for obstructive sleep apnea syndrome.

PURPOSE: The goal of this study was to evaluate the patient's perception of the facial appearance after maxillomandibular advancement (MMA) surgery for obstructive sleep apnea syndrome (OSAS). PATIENTS AND METHODS: During a 14-month period, 58 patients underwent MMA for OSAS. All of the patients underwent preoperative and postoperative cephalometric analysis. Between 6 and 12 months after surgery, a questionnaire was mailed to each patient. The questionnaire asked the patient to evaluate subjectively their postoperative facial appearance. Visual analog scale ([VAS] 0 to 10) was used to assess the extent of the facial changes. RESULTS: Forty-four (76%) patients (39 men, 6 women) responded to the questionnaire. Cephalometric analysis revealed that 40 patients had maxillomandibular protrusion postoperatively. Forty-two (96%) of the 44 patients reported changes in their facial appearance (VAS, 4.8 +/- 2.5). Twenty-four (55%) patients reported favorable facial changes (ie, they were more attractive [15 patients] and/or more youthful). Fourteen patients gave neutral responses (ie, they were no more or no less attractive). Four patients gave unfavorable responses (ie, they were less attractive after surgery). CONCLUSION: The results suggest that most patients who underwent MMA for OSAS noted moderate changes in their facial appearance. Despite significant maxillomandibular protrusion based on the postoperative cephalometric analysis, more than 90% of the patients gave either positive or neutral responses to the changes in their facial appearance.

Adult↗
PubMed2001

Obstructive sleep apnea surgery: genioglossus advancement revisited.

PURPOSE: This study evaluated the accuracy of a genioglossus advancement (GA) technique (rectangular window) to incorporate the genial tubercle/genioglossus muscle complex (GGC) in patients with obstructive sleep apnea. METHODS: This prospective study consisted of 38 consecutive patients who underwent GA. Preoperative localization of the GGC was based on the cephalometric and panoramic radiographs, as well as digital palpation in the floor of mouth. Immediately after completion of the osteotomy, the presence of the genial tubercles and the amount of the genioglossus muscle captured in the bone flap were examined directly. RESULTS: All 38 pairs of genial tubercles were captured. Thirty-one patients had both bellies of the genioglossus muscle incorporated. Two patients had a complete belly and a partial (>50%) belly of the muscle captured. Five patients had only a portion (>50%) of both muscle bellies included. The incomplete incorporation of the muscles in the bone flap was caused by the limited lateral extension of the osteotomy beyond the genial tubercles. The causes of the limited lateral osteotomy extension included crowding of the lower incisors as well as the presence of elongated and/or medially angulated canine roots. CONCLUSION: The results of this study show that the rectangular osteotomy technique accurately captures the genial tubercles and enables an adequate amount of the genioglossus muscle to be incorporated and advanced. However, limited lateral extension of the osteotomy can result in a decreased incorporation of genioglossus muscle in some patients.

Female↗
PubMed2001

Uvulopalatopharyngoplasty, maxillomandibular advancement, and the velopharynx.

OBJECTIVE: To evaluate the presence of velopharyngeal insufficiency (VPI) symptoms and the associated changes of the velopharyngeal anatomy in patients who underwent maxillomandibular advancement (MMA) for persistent obstructive sleep apnea (OSA) after uvulopalatopharyngoplasty (UPPP). METHODS: Preoperative and postoperative cephalometric radiographs were analyzed to assess the anatomic changes of the velopharynx. In addition, a questionnaire survey was sent to the patients between 6 to 12 months after MMA. The questionnaires evaluated the presence and extent of VPI symptoms, including nasal regurgitation while eating or drinking as well as hypernasal speech. A 10-cm visual analog scale (VAS 0-10) was included to assess the impact of VPI symptoms on the patient's quality of life. In the patients who reported VPI symptoms, telephone interviews were conducted 1 year after the survey to evaluate the changes in VPI symptoms over time. RESULTS: Fifty-two of the 65 questionnaires were returned. Five patients (9.6%) reported nasal regurgitation of liquids when drinking hastily, with 2 patients reporting the occurrences as occasional and 3 patients reporting as rare. The impact of these symptoms on the patient's quality of life was minimal (VAS 0.6 +/- 0.4). Regurgitation of food or hypernasal speech was not reported. The telephone interviews 1 year later revealed that the symptoms have completely resolved in all 5 patients. Comparison of the preoperative and postoperative cephalometric radiographs demonstrated the pharyngeal depth increase was 48% of the amount of maxillary advancement and the functional pharyngeal length increased 53% of the maxillary advancement. The functional depth of the pharynx after MMA was significantly greater in the patients with VPI symptoms (P=.01). CONCLUSION: The results of this study suggest that patients who undergo MMA for persistent OSA after UPPP have a low risk of developing VPI. If symptoms occur postoperatively, they are mild and have minimal effect on the patient's quality of life; moreover, the symptoms usually resolve over time.

Cephalometry↗
PubMed2001

Risk factors for sleep bruxism in the general population.

OBJECTIVE: Sleep bruxism can have a significant effect on the patient's quality of life. It may also be associated with a number of disorders. However, little is known about the epidemiology of sleep bruxism and its risk factors in the general population. DESIGN: Cross-sectional telephone survey using the Sleep-EVAL knowledge based system. SETTINGS: Representative samples of three general populations (United Kingdom, Germany, and Italy) consisting of 158 million inhabitants. PARTICIPANTS: Thirteen thousand fifty-seven subjects aged > or = 15 years (United Kingdom, 4,972 subjects; Germany, 4,115 subjects; and Italy, 3,970 subjects). INTERVENTION: None. MEASUREMENTS: Clinical questionnaire on bruxism (using the International Classification of Sleep Disorders [ICSD] minimal set of criteria) with an investigation of associated pathologies (ie, sleep, breathing disorders, and psychiatric and neurologic pathologies). RESULTS: Grinding of teeth during sleep occurring at least weekly was reported by 8.2% of the subjects, and significant consequences from teeth grinding during sleep (ie, muscular discomfort on awakening, disturbing tooth grinding, or necessity of dental work) were found in half of these subjects. Moreover, 4.4% of the population fulfilled the criteria of ICSD sleep bruxism diagnosis. Finally, subjects with obstructive sleep apnea syndrome (odds ratio [OR], 1.8), loud snorers (OR, 1.4), subjects with moderate daytime sleepiness (OR, 1.3), heavy alcohol drinkers (OR, 1.8), caffeine drinkers (OR, 1.4), smokers (OR, 1.3), subjects with a highly stressful life (OR, 1.3), and those with anxiety (OR, 1.3) are at higher risk of reporting sleep bruxism. CONCLUSIONS: Sleep bruxism is common in the general population and represents the third most frequent parasomnia. It has numerous consequences, which are not limited to dental or muscular problems. Among the associated risk factors, patients with anxiety and sleep-disordered breathing have a higher number of risk factors for sleep bruxism, and this must raise concerns about the future of these individuals. An educational effort to raise the awareness of dentists and physicians about this pathology is necessary.

Adolescent↗
PubMed2000

On the concentrations of cyclins and cyclin-dependent kinases in extracts of cultured human cells.

Cyclins and cyclin-dependent kinases (CDKs) are key regulators of the human cell cycle. Here we have directly measured the concentrations of the G(1) and G(2) cyclins and their CDK partners in highly synchronized human cervical carcinoma cells (HeLa). To determine the exact concentrations of cyclins and CDKs in the cell extracts, we developed a relatively simple method that combined the use of (35)S-labeled standards produced in rabbit reticulocyte lysates and immunoblotting with specific antibodies. Using this approach, we formally demonstrated that CDC2 and CDK2 are in excess of their cyclin partners. We found that the concentrations of cyclin A2 and cyclin B1 (at their peak levels in the G(2) phase) were about 30-fold less than that of their partner CDC2. The peak levels of cyclin A2 and cyclin E1, at the G(2) phase and G(1) phase, respectively, were only about 8-fold less than that of their partner CDK2. These ratios are in good agreement with size fractionation analysis of the relative amount of monomeric and complexed forms of CDC2 and CDK2 in the cell. All the cyclin A2 and cyclin E1 are in complexes with CDC2 and CDK2, but there are some indications that a significant portion of cyclin B1 may not be in complex with CDC2. Furthermore, we also demonstrated that the concentration of the CDK inhibitor p21(CIP1/WAF1) induced after DNA damage is sufficient to overcome the cyclin-CDK2 complexes in MCF-7 cells. These direct quantitations formally confirmed the long-held presumption that CDKs are in excess of the cyclins in the cell. Moreover, similar approaches can be used to measure the concentration of any protein in cell-free extracts.

Adenocarcinoma↗
PubMed2000

Transcriptional activation by the Ewing's sarcoma (EWS) oncogene can be cis-repressed by the EWS RNA-binding domain.

The Ewing's sarcoma (EWS) oncogene contains an N-terminal transcriptional activation domain (EWS activation domain, EAD) and a C-terminal RNA-binding domain (RBD). Although it has been established that the EAD is a potent trans-activation domain that is required for the oncogenic activity of several EWS fusion proteins (EFPs), the precise function of the RBD and the normal role of intact EWS are poorly characterized. Here we show that a cis-linked RBD can strongly and specifically repress trans-activation by the EAD. Fusion proteins containing the RBD are expressed at normal levels, are nuclear-localized, and can bind to DNA both in vitro and in vivo, demonstrating that the RBD represses trans-activation directly at the promoter. The RNA recognition motif within the RBD is not required for repression, whereas regions of the RBD containing multiple RGG motifs play a critical role. The finding that the RBD can antagonize transcriptional activation by EWS provides the first direct evidence of a role for the RBD in transcription. Further studies of the repression phenomenon should illuminate key molecular interactions that distinguish EWS from EFPs and provide insights into the normal cellular function of EWS.

Cell Line↗
PubMed2000

Comparison of postoperative pain between laser-assisted uvulopalatoplasty, uvulopalatopharyngoplasty, and radiofrequency volumetric tissue reduction of the palate.

OBJECTIVES: This study compares the posttreatment discomfort between laser-assisted uvulopalatoplasty (LAUP), uvulopalatopharyngoplasty (UPPP), and radiofrequency volumetric tissue reduction (RFVTR) of the palate through the use of visual analog pain scales and a quantitative assessment of the analgesic medication taken. METHODS: In one group, LAUP (n = 10) or UPPP (n = 9) was used to treat patients' snoring or sleep-disordered breathing (SDB), and the other group underwent RFVTR (n = 22). RESULTS: The mean numbers of days with pain after RFVTR, LAUP, and UPPP were 2.6, 13.8, and 14.3 days, respectively. Narcotic analgesics were required in the RFVTR, LAUP, and UPPP groups in 9%, 100%, and 100% of the subjects, respectively. The mean number of these days requiring narcotic pain medications for RFVTR, LAUP, and UPPP was 0.2, 11.8, and 12.4 days, whereas the total narcotic equivalent was 0.3, 7.4 and 29.6 days, respectively. CONCLUSION: RFVTR of the soft palate produced less posttreatment pain than LAUP or UPPP. LAUP and UPPP appeared to show little difference in the severity or duration of posttreatment discomfort.

Adolescent↗
PubMed2000

Radiofrequency volumetric reduction of the palate: An extended follow-up study.

OBJECTIVE: The goal was to evaluate the effect of radiofrequency (RF) of the palate on speech, swallowing, taste, sleep, and snoring 12 to 18 months after treatment. METHODS: Twenty-two patients were evaluated by clinical examination, questionnaires, and visual analog scales. The patients with relapse of snoring were offered further RF treatment. RESULTS: After a mean follow-up of 14 months, no adverse effect was reported. Subjective snoring scores relapsed by 29% overall. Nine patients (41%) noted relapse of snoring from 2.1 +/- 1. 1 to 5.7 +/- 2.7 (P < 0.001). Eight of the patients underwent further RF treatment with a reduction of snoring from 5.8 +/- 2.9 to 3.3 +/- 3.1 (P = 0.01). CONCLUSION: The success of RF volumetric reduction of the palate diminishes with time, as with other surgical procedures of the palate. However, the minimal invasiveness of the RF provided a high patient acceptance for retreatment, and relapse of snoring can be improved.

Adult↗
PubMed2000

Surgery and obstructive sleep apnea: long-term clinical outcomes.

OBJECTIVE: Outcome data on the surgical treatment of obstructive sleep apnea are, in general, based on short-term follow-up (<6-9 months). This examination was undertaken to assess long-term results. METHODS: Forty patients who underwent soft tissue and skeletal surgery were the subjects of this review. Methods of evaluation included polysomnographic variables (respiratory disturbance index [RDI], low oxyhemoglobin desaturation [LSAT]), body mass index, quality-of-life assessments, roentgenographic analysis, and complications. Statistical analysis used the SAS 6.12 system. RESULTS: Thirty-six of 40 patients (90%) showed long-term clinical success. The mean preoperative RDI, nasal continuous positive airway pressure RDI, and long-term RDI were 71.2 +/- 27.0, 7.6 +/- 5.2 and 7.6 +/- 5.1, respectively. The mean preoperative LSAT, nasal continuous positive airway pressure LSAT, and long-term LSAT were 67. 5% +/- 14.8%, 87.1% +/- 3.2%, and 86.3% +/- 3.9%, respectively. The mean follow-up was 50.7 +/- 31.9 months. The patients showed a statistically significant long-term weight gain (P = 0.0002) compared with their 6-month postoperative level (body mass index 31. 4 +/- 6.7 vs 32.2 +/- 6.3). There was a positive correlation with the amount of skeletal advancement and clinical outcome. CONCLUSION: Comprehensive evaluation and surgical treatment can result in successful long-term clinical outcome.

Adult↗
PubMed2000

Evaluation of a new procedure for nasal alar rim and valve collapse: nasal alar rim reconstruction.

OBJECTIVE: A new operative technique to improve nasal valve collapse by placement of cartilage struts along the alar rim was compared with the standard nasal valve cartilage graft (NVG) technique. METHODS AND PATIENTS: A retrospective study of consecutive patients with nasal valve collapse was performed at Stanford University Medical Center. Seventy-nine patients with nasal valve collapse underwent reconstruction with either the classic NVG technique or a newly developed nasal alar rim reconstructive (NARR) procedure. The mean age of the NARR group was 50.13 years (SD +/- 9.40), with 36 men (92.3%) and 3 women (7.7%). The mean age of the NVG group was 52. 14 years (SD +/- 10.83), with 36 men (90%) and 4 women (10%). MAIN OUTCOME MEASURES: These included functional and subjective evaluation of nasal valve collapse. RESULTS: Forty patients (50.6%) underwent the NVG technique, and 39 (49.4%) received the NARR procedure. The NVG technique revealed 0% worsened, 15.0% (6/40) unchanged, 25.0% (10/40) improved, and 60% (24/40) free of obstruction. The NARR procedure revealed 2.6% worsened, 2.6% unchanged, 7.7% improved, and 87.1% free of obstruction. CONCLUSIONS: Nasal alar cartilage struts placed along the caudal alar rim offers sufficient support to the alar rim and valve area. This procedure appears to be as effective as currently available reconstructive alternatives, while being technically uncomplicated.

Cartilage↗
PubMed2000

Fiberoptic nasopharyngolaryngoscopy for airway monitoring after obstructive sleep apnea surgery.

PURPOSE: This study evaluated the upper airway characteristics in the early postoperative period after reconstructive surgery for obstructive sleep apnea (OSA). METHODS: During a 24-month period, the upper airway of patients who underwent uvulopalatopharyngoplasty (UPPP) with genioglossus advancement (GA) or hyoid myotomy (HM) or maxillomandibular advancement (MMA) were evaluated with fiberoptic nasopharyngolaryngoscopy (NPG) preoperatively and 24 to 72 hours postoperatively. RESULTS: NPG was performed on 271 patients. One hundred seventy-three patients had UPPP with GA or HM, and the remainder had MMA. All of the patients who underwent UPPP with GA or HM were found to have varying degrees of soft tissue edema involving the soft palate and the tongue base. The patients who underwent tonsillectomies and UPPP with GA or HM had greater soft palate/pharyngeal wall edema. In contrast, patients who underwent MMA had minimal edema involving the soft palate and the base of tongue, but diffuse lateral pharyngeal wall edema throughout the upper airway was identified. Eighteen of the MMA patients had ecchymosis and edema involving the pyriform sinus and aryepiglottic fold; 4 of these patients also had a hypopharyngeal hematoma involving the pyriform sinus, aryepiglottic fold, arytenoid, and false vocal cord, which partially obstructed the airway. These 4 patients were closely monitored for 1 to 2 additional days, and all were discharged without problems. None of the patients in the study had postoperative airway obstruction. CONCLUSION: NPG may be useful in postoperative airway monitoring and assist in discharge planning after upper airway reconstruction in the OSA patients.

Airway Obstruction↗
PubMed2000

Obstructive sleep apnea surgery: patient perspective and polysomnographic results.

OBJECTIVE: The goal of this study was to assess the outcomes of obstructive sleep apnea (OSA) surgery based on the patient perspective and polysomnographic data. STUDY DESIGN: Fifty-six patients with severe OSA completed the 2-phase reconstructive protocol. A minimum of 6 months after the phase II surgery and after the postoperative polysomnography, questionnaires with visual analog scales (VAS 0-10) were mailed to the patients to assess their perceptions of treatment results. RESULTS: Forty-two (75%) questionnaires were returned. The mean patient age was 46.3 years. The mean respiratory disturbance index improved from 58.7 to 10.0. The mean lowest oxygen saturation improved from 76.3 to 87.3%. All 42 patients reported improved sleep (VAS 8.7). Although 10 patients reported changes in speech, the changes were insignificant, with 9 of the patients scoring 0 on the VAS (VAS 0.08 +/-0.3). Five patients reported changes in swallowing, and their VAS scores were 0.5, 0.9, 1.0, 2.7, and 6.9 (mean VAS 2.4+/-2.7). Forty patients (95%) were satisfied with their results and would undergo the reconstruction again. CONCLUSION: Surgical airway reconstruction for severe OSA is a highly effective treatment option base on the objective as well as the subjective assessment.

Female↗
PubMed2000

Postoperative airway findings after maxillomandibular advancement for obstructive sleep apnea syndrome.

OBJECTIVE: To evaluate the upper airway characteristics in the early postoperative period after maxilomandibular advancement for obstructive sleep apnea syndrome. METHODS: Nasopharyngolaryngoscopy was performed before and 48 hours after surgery on 70 consecutive patients who underwent maxillomandibular advancement for obstructive sleep apnea syndrome. The preoperative and the postoperative evaluations were performed by the same examiner for consistency. RESULTS: Mild to moderate lateral pharyngeal wall edema was identified in 70 consecutive patients. Fourteen patients (20%) had edema as well as ecchymosis involving the pyriform sinus and aryepiglottic fold. Four of these patients (6%) were also noted to have hypopharyngeal hematoma involving the pyriform sinus, aryepiglottic fold, arytenoid, and false vocal cord that partially obstructed the airway. These four patients were closely monitored for 1 to 2 additional days for possible expanding hematoma leading to airway compromise. None of these patients were found to have airway difficulty, and the minimum oxygen saturation was more than 90% throughout the hospitalization. All four patients were discharged uneventfully, and the hematoma resolved completely within 10 days. CONCLUSION: Although postoperative edema was expected after maxillomandibular advancement, hypopharyngeal hematoma was unexpected. Although none of our patients had evidence of airway difficulty, the possibility of an expanding hypopharyngeal hematoma should be considered in patients complaining of breathing difficulty after maxillomandibular advancement surgery.

Adult↗