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Biomedical subjects

P Woo

Publications and source records attributed to P Woo.

At least 91 records · Page 5Linked to original sources
PubMed1997

Severe juvenile dermatomyositis complicated by pancreatitis.

We report two boys with juvenile dermatomyositis (JDM) complicated by pancreatitis. One also had hepatitis and probably mild bowel vasculitis, while the other had catastrophic bowel vasculitis with multiple perforations. Both were on corticosteroids, but had features of active vasculitis. The former improved with high-dose i.v. pulsed methylprednisolone, while the latter improved only after immunosuppression with i.v. methylprednisolone, cyclophosphamide and plasmapheresis. Although bowel vasculitis is a known complication of severe JDM, pancreatitis and hepatitis are extremely rare. We have found in a literature search only three other reports of pancreatitis complicating JDM. We wish to alert physicians that pancreatitis may develop in JDM. It should be considered as a differential diagnosis in the child with active disease who develops abdominal pain. Control of vasculitis with adequate immunosuppression, as well as general supportive measures, may be valuable in the treatment of pancreatitis in JDM.

Adolescent↗
PubMed1997

Kaposi's sarcoma of the larynx.

Kaposi's sarcoma (KS) is a neoplastic vascular disorder, classically arising in the skin of the lower extremities. As a consequence of the acquired immunodeficiency syndrome (AIDS) epidemic, an increasing number of patients have been found to have KS. In AIDS patients, KS appears to exhibit a more diffuse nature and frequently affects the head and neck. Mucosal lesions are most often seen, commonly involving the oral cavity. Only rare cases of laryngeal involvement have been recorded in the literature. We report 2 cases of KS of the supraglottic larynx. Our first patient, an elderly man of Mediterranean descent, complained of voice change and throat discomfort. Endoscopy with biopsy for diagnosis allowed conservative treatment with chemotherapy. Our second patient was a younger man with AIDS who presented with symptoms of airway obstruction. Management with carbon dioxide laser epiglottectomy was successful in relieving that patient's symptoms. Although rare, KS may present in both healthy and immunocompromised patients, and must be considered in the differential diagnosis of all violaceous lesions of the larynx.

Acquired Immunodeficiency Syndrome↗
PubMed1997

The cytokine network in juvenile chronic arthritis.

This is a brief overview of the cytokine network within juvenile chronic arthritis, introducing the concept of the production of T-helper 1 (TH-1) or TH2-cell differentiation as a result of cytokine production, as well as the concept of the balance between pro- and anti-inflammatory cytokines. The balance of TH1 and TH2 cells of pro- and anti-inflammatory cytokines could be altered as a result of genetic differences in the expression levels of a number of key cytokines and may be the critical events leading to chronic inflammation. Finally, the importance of identifying molecular targets for intervention therapy to change the balance of the cytokine network is proposed.

Animals↗
PubMed1996

Expression of recombinant human serum amyloid A in mammalian cells and demonstration of the region necessary for high-density lipoprotein binding and amyloid fibril formation by site-directed mutagenesis.

Site-directed mutagenesis of the acute-phase human serum amyloid A (SAA1 alpha) protein was used to evaluate the importance of the N-terminal amino acid residues, namely RSFFSFLGEAF The full-length cDNA clone of SAA1 alpha (pA1.mod.) was used to create two mutations, namely Gly-8 to Asp-8 and an 11 amino acid truncation between Arg-1 and Phe-11 respectively. Wild-type and mutant cDNAs were expressed in Chinese hamster ovary (CHO) cells under the control of the human cytomegalovirus promoter, which resulted in the secretion of the processed proteins into the culture media. Wild-type recombinant human SAA (rSAA) protein was shown to have pI values of 6.0 and 6.4, similar to the human SAA isoform SAA1 alpha and SAA1 alpha desArg found in acute-phase plasma. N-terminal sequencing of 56 residues confirmed its identity with human SAA1 alpha. The total yield of wild-type rSAA measured by ELISA was between 3.5 and 30 mg/l. The two mutations resulted in reduced expression levels of the mutant SAA proteins (3-10 mg/l). Further measurements of rSAA concentration in lipid fractions of culture medium collected at a density of 1.21 g/ml (high-density liporotein; HDL) and 1.063-1.18 g/ml (very-low-density lipoprotein/low-density lipoprotein; VLDL/LDL) showed that 76% of the wild-type protein was found in the HDL fraction and the remaining 24% in the infranatant non-lipid fraction. In contrast the relative concentration of mutant rSAA in HDL and infranatant fractions was reversed. This is consistent with the previously proposed involvement of the 11 amino acid peptide in anchoring. SAA protein on to HDL3 [Turnell, Sarra, Glover, Baum, Caspi, Baltz and Pepys (1986) Mol. Biol. Med. 3, 387-407]. Wild-type rSAA protein was shown to from amyloid fibrils in vitro under acidic conditions as shown by electron microscopy, and stained positive with Congo Red and exhibited apple-green birefringence when viewed under polarized light. Under the same conditions mutSAA(G8D) and mutSAA delta 1-11 did not form amyloid fibrils. In conclusion, replacement of Gly-8 by Asp-8 or deletion of the first 11 amino acid residues at the N-terminus of rSAA diminishes its capacity to bind to HDL and decreases amyloid fibril formation.

Amyloid↗
PubMed1996

Childhood-onset scleroderma: is it different from adult-onset disease.

OBJECTIVE: To distinguish childhood-onset scleroderma from adult-onset disease. METHODS: The clinical and serologic features of 58 patients with childhood-onset scleroderma (11 patients with diffuse cutaneous systemic sclerosis [SSc], 16 with linear SSc, 14 with linear morphea, and 17 with morphea) were examined in the largest cohort of such patients studied to date. These parameters were compared with data obtained from patients with adult-onset disease. RESULTS: Childhood-onset scleroderma resembled adult-onset disease with regard to the heterogeneity of clinical expression and subsets of disease, but it also differed from adult-onset disease in a number of clinical and laboratory parameters. The predominant childhood-onset disease presentation was the localized form of the disease, with limited and diffuse SSc being less notable. There was a significant association of trauma with childhood-onset scleroderma (P < 0.0001), which was not noted in adult-onset disease. Furthermore, in contrast to adult disease, patients with childhood-onset disease had normal levels of parameters of vascular activation (von Willebrand factor, angiotensin-converting enzyme, E-selectin, and endothelin-1), T cell activation (soluble interleukin-2 receptors), and collagen synthesis (carboxy-terminal type I and amino-terminal type III), a notable lack of anticentromere antibodies, and abnormal coagulation indices. CONCLUSION: A number of features distinguish childhood-onset scleroderma from adult-onset disease.

Adolescent↗
PubMed1996

Association of esophageal reflux and globus symptom: comparison of laryngoscopy and 24-hour pH manometry.

Thirty-one patients with globus sensation were examined by dual probe pH manometry and videolaryngoscopy to investigate the role of gastroesophageal reflux disease in association with globus. Abnormal laryngeal findings, which included grossly abnormal and subtle changes, were seen in 17 patients. These findings included pharyngeal erythema (12 patients), interarytenoid pachydermia (11), laryngeal edema (11), arytenoid erythema (9), and thick mucus (3). Twenty-one of the 31 pH probe studies showed gastroesophageal reflux disease (14 grossly abnormal, 6 borderline abnormal) with Johnson and DeMeester composite scores for the distal probe. There was no correlation between the upright and supine position, nor was there correlation between positive laryngeal findings and a positive pH probe study. We conclude that globus sensation is often a nonspecific symptom of laryngopharyngeal irritation in which gastroesophageal reflux disease plays a significant role. Combining careful laryngoscopic examination with pH probe studies can help to differentiate between patients with organic pathology caused by gastroesophageal reflux disease and patients with other nonspecific laryngopharyngeal disorders.

Adult↗
PubMed1996

Assessment of the infant airway with videorecorded flexible laryngoscopy and the objective analysis of vocal fold abduction.

Accurate diagnosis of upper airway abnormalities by flexible laryngoscopy in infants is hampered by rapid laryngeal motion and lack of patient cooperation. This study evaluates the added role of videorecorded flexible laryngoscopy and the objective measurement of vocal fold abduction in improving the diagnosis of upper airway abnormalities in infants. Seventy-eight infants had videorecorded flexible laryngoscopy performed as part of their evaluation of a suspected airway disorder. These recordings were reviewed by three otolaryngologists for confirmation of the clinical diagnosis. From the video image, the maximum angle of vocal fold abduction was measured with image analysis software. Of 78 patients 40 had supraglottic or glottic abnormalities, 9 had nasal or nasopharyngeal obstruction, 9 had subglottic abnormalities (diagnosed subsequent to videolaryngoscopy), and 15 patients had normal findings on examination. Of those with laryngeal abnormalities, laryngomalacia was the most common diagnosis (23 of 78). Vocal fold paralysis was present in 4 patients. A separate group (9 of 78) of patients was identified as having symmetric bilateral limitation of vocal fold abduction. Laryngeal dyskinesia was diagnosed in these 9 patients. The mean values of maximal vocal fold abduction were as follows: (1) normals, 59.5 degrees; (2) laryngomalacia, 57.0 degrees; (3) paralysis, 26.6 degrees; and (4) incomplete abduction with laryngeal dyskinesia, 27.6 degrees. Videolaryngoscopy is a valuable tool for documentation, parent education, and analysis of infant laryngeal abnormalities. Repeat viewing of the video examination and frame-by-frame analysis improve the diagnostic accuracy. Using this approach, we have calculated the anterior glottic abduction angle in the normal and abnormal infant larynx. In addition, we have identified a group of infants with incomplete abduction of the vocal folds that appears to be different from that found in vocal cord paralysis.

Airway Obstruction↗
PubMed1996

Quantification of videostrobolaryngoscopic findings--measurements of the normal glottal cycle.

Videostrobolaryngoscopic (VSL) images of vocal fold behavior in 32 male and 33 female normal speakers were analyzed by computer. Image analysis software enhanced the glottal image, allowing extraction of the glottal area. Frame-by-frame analysis produced 20 glottal area values for each glottal cycle. The glottal area waveform (GAW) plots these values. From the GAW, features such as peak glottal area, duration of opening and closing, and rates of vocal fold opening and closing were measured. Acoustic measures of sound pressure level (SPL) and fundamental frequency were used to compare changes in GAW with changes in loudness and pitch. Analysis of the data showed significant differences between the sexes in GAW, peak glottal area, closed period, closing slope, and size and incidence of the posterior glottal gap. Intensity and frequency changes significantly affected GAW. Intensity variations affected the steepness of the closing phase and the duration of the closed period. Frequency changes affected the open period and the relative duration of opening vs. closing. This study provides quantitative measures of the VSL image that supplement and corroborate perceptual observations. These measures provide normative data against which similar measures of dysphonic larynges can be compared.

Adult↗
PubMed1996

Echo-planar magnetic resonance imaging of deglutitive vocal fold closure: normal and pathologic patterns of displacement.

Abnormalities of vocal fold closure during deglutition predispose to aspiration due to impairment of airway protection. Conventional assessment of deglutitive vocal fold motion with laryngoscopy does not permit visualization through a complete adduction-abduction cycle. We determined spatiotemporal patterns of deglutitive vocal fold adduction through echo-planar magnetic resonance imaging in 15 normal volunteers and 6 patients with vocal fold paralysis. In normal volunteers, deglutitive vocal fold adduction was synchronized with laryngeal elevation, with complete vocal fold closure at the apex. Patients with unilateral vocal fold paralysis demonstrated reduced elevation and medial movement of the involved vocal fold. At maximal laryngeal elevation the uninvolved vocal fold attained a position superior to the paralyzed fold, resulting in level differences and an interglottic gap. Patients with bilateral vocal fold paralysis demonstrated reduced elevation and medial movement of both vocal folds. These findings indicate that normal and abnormal patterns of vocal fold displacement can be distinguished noninvasively through the use of echo-planar imaging.

Adult↗
PubMed1996

Vocal fold scarring: current concepts and management.

Scarring of the vocal folds can occur as the result of blunt laryngeal trauma or, more commonly, as the result of surgical, iatrogenic injury after excision or removal of vocal fold lesions. The scarring results in replacement of healthy tissue by fibrous tissue and can irrevocably alter vocal fold function and lead to a decreased or absent vocal fold mucosal wave. The assessment and treatment of persistent dysphonia in patients with vocal fold scarring presents both diagnostic and therapeutic challenges to the voice treatment team. The common causes of vocal fold scarring are described, and prevention of vocal fold injury during removal of vocal fold lesions is stressed. The anatomic and histologic basis for the subsequent alterations in voice production and contemporary modalities for clinical and objective assessment will be discussed. Treatment options will be reviewed, including nonsurgical treatment and voice therapy, collagen injection, fat augmentation, endoscopic laryngoplasty, and Silastic medialization.

Cicatrix↗
PubMed1996

Long term follow-up of children with mixed connective tissue disease.

Mixed connective tissue disease (MCTD) is characterized by features of more than one of the rheumatic disorders with antinuclear antibodies in a speckled pattern and with antibodies to nuclear ribonucleoprotein (nRNP). MCTD is uncommon in children and long-term follow-up studies in children are infrequently reported. A retrospective review of clinical experience at five pediatric rheumatology centers provided 11 patients who met the following inclusion criteria: (1) Kasukawa's criteria for MCTD1; (2) presentation younger than 18th birthday; (3) greater than five years of follow-up; (4) completion of data collection form. The widely varying outcomes of these 11 children with MCTD on long-term follow-up may lend doubt that this is a unique and distinctive rheumatologic disorder.

Adolescent↗
PubMed1996

Pediatric rheumatology in the United Kingdom: data from the British Pediatric Rheumatology Group National Diagnostic Register.

OBJECTIVE: To establish a computerized national diagnostic register for pediatric rheumatology in the UK; to describe the demography and diagnostic classification of children referred to pediatric rheumatology clinics; to estimate the current incidence of juvenile arthritis (JA) in the UK. METHODS: A diagnostic register was established in 1989: 23 centers have contributed data on all new cases seen since they joined the register; 18 centers have also contributed data on all current attenders. For 2 centers with well defined catchment areas, the incidence of JA was estimated. RESULTS: A total of 4948 cases were registered, of whom 2962 (60%) were female. 1991 (40%) had a diagnosis of JA. The 2nd largest category was mechanical/orthopedic problems (24%). Pauciarticular juvenile chronic arthritis was the most common subtype of JA. Seropositive RA was rare. Tertiary referral centers saw proportionately more JA and district general hospitals saw proportionately more mechanical problems. The annual incidence rate for JA from 2 centers was 10/100,000, and for all rheumatic disorders was 32-42/100,000 children under age 16. CONCLUSION: The relative proportion of patient diagnoses varies between centers. Nevertheless, the incidence of hospital referred JA seems very uniform.

Adolescent↗
PubMed1995

Rheumatoid nodules of the larynx.

Two unique cases of rheumatoid nodules affecting the larynx are reported. These subcutaneous nodules represent localized laryngeal involvement from autoimmune disorders. The otolaryngologist should be aware of these possibilities as part of the differential diagnosis in the workup of dysphonia.

Adult↗
PubMed1995

Physiological characteristics of the supported singing voice. A preliminary study.

The purpose of this study was to develop a definition of the supported singing voice based on physiological characteristics by comparing the subjects' concepts of a supported voice with objective measurements of their supported and unsupported voice. This preliminary report presents findings based on data from eight classically trained singers. Subjects answered questions about their concepts of the characteristics of the supported singing voice and how it is produced. Samples of the supported and unsupported singing voice produced at low, medium, and high pitches at a comfortable loudness level were collected for acoustic, spectral, airflow, electroglottographic, air volume, and stroboscopic analyses. Significant differences between the supported and unsupported voice were found for sound pressure level (SPL), peak airflow, subglottal pressure (Ps), glottal open time, and frequency of the fourth formant (F4). Mean flow and F2 frequency differences were sex and pitch related. Males adjusted laryngeal configuration to produce supported voice, whereas glottal configuration differences were greater in females. Breathing patterns were variable and not significantly different between supported and unsupported voice. Subjects in this study believe that the supported singing voice is resonant, clear, and easy to manage and is produced by correct breath management. Results of data analysis show that the supported singing voice has different spectral characteristics from and higher SPL, peak airflow, and Ps than the unsupported voice. Singers adjust laryngeal and/or glottal configuration to account for these changes, but no significant differences in breathing activity were found.

Acoustics↗
PubMed1995

Stroboscopic signs associated with benign lesions of the vocal folds.

Stroboscopic signs were systematically rated for a group of 80 patients with benign vocal fold lesions, most of whom had either a nodule or a polyp. Each group revealed a characteristic pattern of ranking of signs and exhibited differences of most predominant signs. The results of the ratings were submitted to a multiple discriminant analysis to determine if post hoc stroboscopic ratings could be used to correctly classify patients into one of four diagnostic groups and into one of two treatment groups. All patients except one were correctly classified into the diagnostic groups, and all were correctly classified into the treatment groups. The important signs for classifying patients into the diagnostic groups were roughness of the edge of the affected vocal fold, phase closure pattern, and phase symmetry. The important signs for classifying patients into the treatment groups were roughness of the edge of the affected vocal fold, glottal closure configuration, and vibration characteristics of the affected (or more affected) vocal fold. The results suggest that objective evaluation of stroboscopic examinations can be valuable in correctly diagnosing patients and in selecting the proper treatment regimen for the patient.

Cysts↗
PubMed1995

Endoscopic microsuture repair of vocal fold defects.

The presence of a nonvibratory segment of vocal folds after microlaryngeal surgery is often a cause of poor voice result. The etiology of a nonvibratory segment is due to full thickness epithelial defect followed by secondary wound closure and scar contracture. To reduce scar contracture and nonvibratory segment of the vocal folds, primary repair with a 6-0 chromic endo-knot suture technique was used to close defects and approximate microflaps of the vocal folds. This was done in 18 patients with epithelial defects after resection of benign vocal fold lesions. The pathologic findings included severe polypoid degeneration (n = 7), fusiform laryngeal polyps (n = 5), sulcus vocalis (n = 2), cyst (n = 2), and keratosis (n = 2). Voice was improved in all patients after surgery. Comparison of vocal fold vibration before and after surgery showed improvements in configuration, amplitude, and mucosal wave. Vocal folds that were sutured all had good vibratory characteristics; none had a nonvibrating segment at the site of suture placement. Voice and healing after microsuture technique were near normal by Day 10 and return of mucosal wave was often complete by Day 14. Endoscopic microsuture closure of microflaps of the vocal folds edge is safe and affords the surgeon an opportunity for primary repair with improved functional result.

Endoscopy↗