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Biomedical subjects

L A Forrest

Publications and source records attributed to L A Forrest.

17 recordsLinked to original sources
PubMed2000

Paradoxical vocal cord dysfunction in juveniles.

OBJECTIVE: To evaluate demographic and videolaryngoscopic features in a large series of juveniles with paradoxical vocal cord dysfunction (PVCD). DESIGN: Case series data from videolaryngoscopic tapes retrospectively evaluated in a masked, controlled fashion, and demographic data collected via retrospective medical chart review. SETTING: A tertiary care otolaryngology and speech pathology referral center. PATIENTS: Twenty-two patients with PVCD aged 18 years and younger diagnosed as having PVCD at The Ohio State University Voice Institute, Columbus. MAIN OUTCOME MEASURES: Age, sex, social history, and medical history (demographic); epiglottic position, arytenoid and interarytenoid appearance, phase 0 stability, true vocal cord respiratory motion, degree of anteroposterior (AP) constriction, and false vocal cord adduction (videolaryngoscopic). RESULTS: Of 22 patients, 18 were girls, and 12 had significant social stressors, particularly organized sports. Nineteen patients had posterior laryngeal changes commonly found in gastroesophageal reflux disease. Twelve patients demonstrated abnormal true vocal cord adduction during quiet respiration. Seven patients demonstrated supraglottic anteroposterior constriction and false vocal cord approximation during phonation. CONCLUSIONS: Juvenile PVCD is more common in girls and is associatedwith social stresses. Anatomic laryngeal changes typically associated with gastroesophageal reflux disease are extremely common in these patients. Juveniles with PVCD frequently demonstrate abnormal true vocal cord adduction during quiet respiration. We recommend that initial evaluation of juvenile patients for possible PVCD be conducted via transnasal fiberoptic laryngoscopy while the patient is asymptomatic, and that strong consideration be given to empiric pharmacological treatment of gastroesophageal reflux disease in juveniles diagnosed as having PVCD.

Adolescent↗
PubMed2000

Quantification of the learning curve for percutaneous dilatational tracheotomy.

OBJECTIVES/HYPOTHESIS: Although numerous investigators have reported a bedside percutaneous dilatational tracheotomy (PDT) complication incidence similar to that of standard operative tracheostomy, others have proposed a "learning curve" for PDT resulting in increased complications early in individual or institutional experience with this procedure. The objective of this investigation is to characterize and quantify the proposed learning curve for PDT. STUDY DESIGN: Prospective analysis of complication incidence for the first 100 PDT procedures performed in a local community hospital Department of General Surgery. METHODS: Demographic data, patient disease variables, and patient anatomic features, as well as perioperative, postoperative, and late complications, were recorded prospectively. Patients were divided into sequential cohorts of 20 and were evaluated for complications at regular intervals. RESULTS: Perioperative and late complication incidence was significantly higher in the first 20 patients who underwent PDT. However, postoperative complication incidence did not significantly vary with operator or institutional experience. In addition, patients with suboptimal anatomy were found to have a significantly increased complication incidence, independent of operator and institutional experience. CONCLUSIONS: Percutaneous dilational tracheotomy has an identifiable learning curve that is most prominent in the first 20 patients treated. Early experience with PDT should be obtained under controlled circumstances, ideally the operating suite. Although most complications occur during acquisition of early experience with PDT, certain life-threatening complications such as tube dislodgment or inability to complete procedure may occur even after extensive experience is obtained. Bedside PDT has an acceptable complication incidence, but any surgeon employing this technique must be prepared to perform immediate standard open tracheotomy to minimize potentially lethal complications of this elective procedure.

Adolescent↗
PubMed1999

Endoscopic and stroboscopic description of adults with paradoxical vocal fold dysfunction.

The purpose of this study was to determine if endoscopic and stroboscopic parameters of voice were normal between attacks of paradoxical vocal fold dysfunction (PVFD). Fifty adults (38 females, 12 males) and 54 adult controls (40 females, 14 males) were examined via endoscopy with and without stroboscopy. Endoscopy indicated paradoxical adduction of the folds during the respiratory cycle of all 50 participants with PVFD, although they were asymptomatic. Atypical laryngeal configurations were observed including abnormality of the anterior-posterior dimension and ventricular fold medialization in both groups of subjects. Stroboscopy demonstrated abnormalities including unstable zero phase, decreased amplitude of vibration, decreased mucosal waves, and phase asymmetry primarily for the PVFD subjects alone. Results indicate that persons with PVFD demonstrate subtle laryngeal abnormality endoscopically and stroboscopically when dyspnea is not reported. This supports the hypothesis that PVFD is not episodic but exists as a continuum of laryngeal instability that may, due to various precipitating factors, be exacerbated to breathing attacks.

Adult↗
PubMed1998

Candida laryngitis appearing as leukoplakia and GERD.

The symptoms and physical findings of reflux laryngopharyngitis are characteristic, but the mucosal alterations evident in the larynx are not exclusive to reflux. When conventional reflux management produces an equivocal response, other etiologic factors such as mycotic laryngitis, need consideration. The differential diagnosis of dysphonia in an immunocompromised patient always includes mycotic infections, but mycotic laryngitis can also occur in the immunocompetent host. Laryngeal candidiasis can produce physical findings, such as erythema and leukoplakia, that are similar to reflux laryngopharyngitis. Predisposing factors include previous radiation therapy, antibiotic therapy, corticosteroids, and any alteration in the mucosal barrier. Diagnosis is established by mucosal biopsy with special staining of the tissue to identify the characteristic hyphae. Treatment of mycoses can be difficult and long-term therapy is often required.

Adult↗
PubMed1998

Review of percutaneous tracheostomy.

The purpose of this study is to assess the safety and efficacy of the four known methods of percutaneous tracheostomy. Perioperative, postoperative, and late complication rates were generated for each method after a complete literature review identified 1684 percutaneous tracheostomy patients reported in 40 series. Two methods, the Toye and the guide wire dilator forceps (GWDF) methods, have been the subject of few investigations. Two other methods have been extensively studied. A high perioperative complication rate was calculated for the Rapitrac method, whereas percutaneous dilational tracheostomy (PDT) has complication rates similar to those reported for standard operative tracheostomy. A retrospective review of 22 patients who underwent PDT at a local community hospital confirmed a "learning curve" for this technique that had been previously suggested. Review of the literature suggests that PDT can be safe and cost-effective for selected patients, but a learning curve for this technique exists that dictates caution, experience, and preparation on the part of any surgeon who wishes to add percutaneous tracheostomy to his or her repertoire.

Clinical Competence↗
PubMed1997

Factors involved in long- and short-term mandibular plate exposure.

OBJECTIVES: To evaluate and to compare rates and timing of exposure of alloplastic mandibular plates by plate type and tissue reconstruction technique. DESIGN: A retrospective review series of 92 consecutive patients for 4 years (mean follow-up, 30 months). SETTING: National Cancer Institute-designated comprehensive cancer center in a freestanding cancer hospital. PATIENTS: Seventy-nine patients received alloplastic mandibular plates for segmental defects, and 13 patients received compression plates for mandibular osteotomies following ablative cancer surgery, including 21 titanium hollow osseointegrating reconstruction, 41 Storz, 16 Synthes, and 5 AO/ASIF (Arbeitsgemein schott fur Ostcosynthese fragen/Association for the Study of Internal Fixation) plates. Primary flap repair was provided by 71 pedicled soft tissue and 19 osseocutaneous free flaps, with primary closure in the remaining 2. INTERVENTION: Most of the reconstructions of the mandibular defect was with an alloplastic plate with musculocutaneous flap or revascularized bone graft. OUTCOME MEASURES: Clinically apparent intraoral or extraoral plate exposure. RESULTS: Plate exposure occurred in 25 cases. Nine plates were exposed extraorally, at a mean postoperative interval of 40 weeks. The remaining 16 plates were exposed intraorally at a mean postoperative interval of 16 weeks. There was no significant difference in the exposure rates of different plate types or methods of reconstruction. The titanium hollow osseointegrating reconstruction plate had a similar exposure rate compared with the other plates. Size and site of the defect were the only significant predictors of plate exposure Radiotherapy and postoperative complications did not affect the rate of exposure. CONCLUSIONS: Extraoral plate exposure occurs less commonly and later in the postoperative period than intraoral exposure, suggesting different causes. Plate type and type of flap reconstruction do not affect the rate of exposure. This may reflect long follow-up.

Bone Plates↗
PubMed1995

Safety of ototopical antibiotics.

A prospective randomized study analyzing the safety and efficacy of a single dose of ototopical antibiotics following human middle ear tympanostomy tube insertion was performed. Fifty children undergoing bilateral tympanostomy tube insertion were studied by the placement of 0.5 mL of Cortisporin Otic Suspension (COS; Burroughs Wellcome Co., Research Triangle Park, N.C.) to one middle ear space by random assignment. Preoperative and postoperative audiograms were obtained, and the presence of otorrhea was noted. In one patient sensorineural hearing loss of 6 dB developed bilaterally, which was symmetric in both the treated and the untreated ear. This preliminary study showed no statistical difference in hearing loss or postoperative otorrhea associated with a single application of Cortisporin to the middle ear space.

Administration, Topical↗
PubMed1995

Rapid analysis of mandibular margins.

Evaluating surgical margins during composite resection of carcinoma is limited by analysis of the bone margins. The standard pathologic evaluation of bone is by decalcification. A method of analysis was devised based on histologically proven methods of cortical invasion and subsequent spread. Frozen section analysis (FSA) of the cancellous bone was investigated as a rapid method of evaluating adequacy of the mandibular resection. Subjects consisted of 29 patients undergoing full-thickness mandibular resection, with 16 cases of histologically proven mandibular invasion qualifying for evaluation. Results of FSA were then compared to the permanent section analysis of the cancellous bone and to the decalcified specimen. Complete correlation was found between frozen and permanent section results. Frozen section analysis was able to correctly predict adequacy of resection in 32 (97%) of 33 margins.

Carcinoma, Squamous Cell↗
PubMed1994

Interaction of proteins with a cytochrome P450 2B2 gene promoter: identification of two DNA sequences that bind proteins that are enriched or activated in response to phenobarbital.

Cytochromes P450 (CYPs) are of central importance in the metabolism of foreign hydrophobic compounds. Members of the CYP2B subfamily are inducible at the transcriptional level by the barbiturate, phenobarbital. Owing to the lack of a suitable phenobarbital-responsive cell line, very little is known regarding the mechanisms by which phenobarbital induces the expression of these genes. We report the use of gel retardation and DNase I footprinting to investigate the presence of regulatory protein binding sites within a CYP2B2 gene promoter. Two DNA sequences, located between -183 to -199 and -31 to -72, have been identified that bind rat liver nuclear proteins that are enriched or activated in vivo by phenobarbital. Gel retardation competition experiments demonstrated that the two sequences bound different proteins. In vitro transcription competition experiments demonstrated that the sequences and the proteins with which they interact are involved in regulating CYP2B2 gene transcription. These two DNA sequences and their cognate binding proteins may play a role in the induction of CYP2B2 gene expression in response to phenobarbital.

Animals↗
PubMed1984

The isolation of a genomic clone containing the apolipoprotein CII gene and the detection of linkage disequilibrium between two common DNA polymorphisms around the gene.

We report the isolation of a genomic clone containing the apolipoprotein CII (apo CII) gene and 5' and 3' flanking sequences. A detailed restriction map of the gene has been constructed and DNA fragments that are unique, or low copy number sequences in the genome have been identified. One of these detects a common restriction fragment length polymorphism (RFLP) with the enzyme BglI. Marked linkage disequilibrium is observed between this RFLP and that detected with the apo CII cDNA clone, even though the two variable restriction enzyme sites are approximately 12kb apart. However, the usefulness of the apo CII gene as a marker for linkage studies is increased by the use of both RFLPs.

Alleles↗
PubMedDate not supplied

Update on intraoperative analysis of mandibular margins.

PURPOSE: Assessing the adequacy of the surgical resection during composite resection of carcinoma is limited by the ability to evaluate the bone margins. The standard pathologic evaluation of bone is by decalcification. PATIENTS AND METHODS: A method of analysis was devised based on histologically proven methods of cortical invasion and subsequent spread. Frozen-section analysis of cancellous bone was investigated as a rapid method of evaluating adequacy of the mandibular resection. This report is an update of previously published results and includes an increase in the sample size as well as the analysis of additional pathology. Subjects consisted of 66 patients undergoing full thickness mandibular resection with 30 cases of histologically proven mandibular invasion qualifying for evaluation. Results on frozen section were then compared to the permanent section analysis on the cancellous bone and to the decalcified specimen. RESULTS: Complete correlation was found between frozen and permanent section results. Frozen section analysis was able to correctly predict adequacy of resection in 60 of 61 margins. CONCLUSION: Based on these results, the oncologic surgeon can evaluate bone margins at the time of the resection and adjust the amount of excision required to eradicate the disease.

Adult↗
PubMedDate not supplied

Influence of plasma lipoproteins on platelet aggregation in a normal male population.

Aggregation tests were performed on platelet-rich plasma from healthy male volunteers to determine the minimum concentration of adenosine diphosphate (ADP), epinephrine, collagen, or thrombin required to induce secondary aggregation. Platelets were also analyzed for cholesterol and phospholipid, and in some cases their membrane fluidity was determined by fluorescence depolarization of the probe, diphenylhexatriene. Concentrations of the major lipoprotein fractions in the plasma were measured and related to the sensitivity of platelets to the four agonists. Low density lipoprotein (LDL) and total cholesterol concentrations, but not high density lipoproteins (HDL) or very low density lipoproteins (VLDL), were positively correlated with sensitivity to aggregation by epinephrine, but not by other agonists. By arrangement of the lipoprotein concentration into quintiles, the effect of LDL was most striking in the lower two quintiles, where the sensitivity to adrenaline and ADP were much diminished. The middle and upper two quintiles showed a similar sensitivity. Lower platelet cholesterol/phospholipid ratios were also associated with a reduced sensitivity to epinephrine or ADP, but only at the lower end of the range. Membrane microviscosity was correlated negatively with collagen sensitivity and with VLDL cholesterol concentrations, but positively with HDL cholesterol concentrations. Platelet behavior appears, therefore, to be influenced by lipoprotein concentrations within the range found in a healthy population.

Adenosine Diphosphate↗
PubMedDate not supplied

Management of orbital blow-out fractures. Case reports and discussion.

Blow-out fractures are fractures of the orbital floor or medial wall that occur as a consequence of blunt trauma. Impact increases the intraorbital pressure, forcing the nondistensible orbital contents through the orbital floor. The fracture is commonly caused by impact from a baseball or tennis ball. However, any blunt trauma to the orbit, as from a knee or elbow, can result in a blow-out fracture. The characteristic clinical findings include double vision, a sunken globe, and numbness in the distribution of the infraorbital nerve. Sometimes, the only sign of a blow-out fracture is the abrupt inflation of periorbital tissue with air when the patient blows his nose. Standard evaluation of these fractures includes history, physical examination, and radiographs. Some patients benefit from computed tomography (CT), which can be both diagnostic and prognostic. Blow-out fractures do not often produce serious sequelae, and the current trend is toward no treatment. However, it is imperative to rule out any serious injury to the eye itself that would require emergency treatment.

Adult↗