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Biomedical subjects

D A Charles

Publications and source records attributed to D A Charles.

10 recordsLinked to original sources
PubMed2001

Helicobacter pylori and tonsillectomy.

Tonsillar tissue is a component of mucosa-associated lymphoid tissue (MALT), which has evolved to protect vulnerable mucosal surfaces. Helicobacter pylori, implicated as an aetiological factor in duodenal ulcers and gastritis, induces the appearance of lymphoid aggregates (MALT) in the stomach. This organism is cytotoxic via a nitric oxide synthase cascade. The possibility that tonsillar tissue processes Helicobacter pylori or that Helicobacter pylori can colonize the palatine tonsils is explored. The study design was that of a prospective study. We determined if Helicobacter pylori (i) forms part of the normal microenvironment of the tonsil, (ii) plays a role in the pathogenesis of tonsillitis and (iii) is associated with increased expression of inducible nitric oxide synthase (iNOS) in macrophages of the tonsil. Serology for Helicobacter pylori was performed on 50 patients undergoing tonsillectomy. Tonsillar specimens were monitored for urease activity by CLO test (a sealed plastic slide holding an agar gel, which contains urea and detects the urease enzyme of Helicobacter pylori), and immunocytochemically probed for Helicobacter pylori and iNOS expression. The mean age of this patient group was 17.2 years (3-36 years). Fourteen (28%) were sero-positive for Helicobacter pylori but no evidence of this pathogen was found in any tonsillar specimen. The number of macrophages staining for iNOS, per field, under a magnification of x40, was increased in sero-positive patients (13.3 +/- 1.3 versus 9.9 +/- 0.7; P = 0.01). Helicobacter pylori does not appear to colonize the tonsil. We believe that Helicobacter pylori primes the tonsils by inducing macrophage iNOS expression. The higher expression in sero-positive patients is a reflection of a pro-inflammatory reaction to Helicobacter pylori that is both local and systemic.

Adolescent↗
PubMed1995

Comparison of botulinum toxin injection procedures in adductor spasmodic dysphonia.

This study compares the effects of unilateral and bilateral thyroarytenoid muscle injections of botulinum toxin in 50 patients with adductor spasmodic dysphonia. Patients were randomly assigned to two treatment groups of 25 patients each and a group of 15 normal control subjects was also included. Using a standard electromyographic guidance procedure, one patient group received unilateral thyroarytenoid muscle injections of 15 units of botulinum toxin, while the second patient group received bilateral thyroarytenoid muscle injections of 2.5 units of botulinum toxin on each side. Follow-up data were obtained at 2- and 6-week intervals. Acoustic and perceptual measures of vocal performance included maximum phonation time, fundamental frequency, standard deviation of fundamental frequency, jitter, shimmer, signal/noise ratio, voice break frequency, spasm severity rating, and vocal breathiness rating. Unilateral and bilateral group comparisons at 2-weeks postinjection revealed no significant difference on any of the measures examined. At 6-weeks postinjection, maximum phonation time was significantly lower in the bilateral group. All other measures failed to differentiate the two patient groups. These results suggest that standard unilateral and bilateral botulinum toxin injections provide equivalent degrees of improvement in the symptoms of spasmodic dysphonia. However, bilateral injections appear to be associated with a longer period of excessive phonatory airflow than do unilateral injections.

Adolescent↗
PubMed1993

Unilateral versus bilateral botulinum toxin injections in spasmodic dysphonia: acoustic and perceptual results.

The present study compared the effects of unilateral and bilateral thyroarytenoid injections of botulinum toxin (botox) for the treatment of adductor spasmodic dysphonia. Using electromyographic guidance, 15 patients received unilateral botox injections of 15 units each and 11 patients received bilateral injections of 2.5 units in each site. Acoustic recordings of the patient's voice were made prior to injection and at two- and six-week intervals after injection. Both the unilateral and bilateral botox injections were associated with significant improvements in spasmodic dysphonia. This was determined by the acoustic measures of vocal shimmer and the number of voice breaks per second and by the perceptual measures of voice spasm severity. Both types of injections were also associated with a significant increase in vocal breathiness at two weeks post-injection. In addition, a number of acoustic measures including maximum phonation time, vocal jitter, and the number of voice breaks/second indicated that unilateral botox injections may provide both superior and longer lasting benefits than bilateral botox injections.

Botulinum Toxins↗
PubMed1990

Trans oral approach to the nasopharynx and clivus using the Le Fort I osteotomy with midpalatal split.

The Le Fort I level osteotomy is a procedure well known to oral and maxillofacial surgeons, who routinely use it to correct midfacial skeletal deformities and alter the dental occlusion. This osteotomy can also be used as a maxillotomy for access to more superiorly and posteriorly situated structures. The downfracture technique provides the surgeon with a safe approach that allows visualization of the maxillary sinuses, nasal cavity, nasopharynx, base of the skull and upper cervical spine. This approach can also be combined with a midline lip split, mandibulotomy and glossotomy to give access to retropharyngeal structures. By modifying the combined Le Fort I and transmandibular approach utilizing a midline split of the hard and soft palate, the access to the clivus can be improved considerably. The clinical applications of these combined procedures in the treatment of basilar invagination and tumors of the nasopharynx are discussed.

Adolescent↗
PubMed1982

Lactating dairy cow responses to dietary sodium, chloride, and bicarbonate during hot weather.

Twelve Holstein and eight Jersey cows in the first half of lactation were assigned to one of four concentrate formulations to provide supplemental sodium salts in the total diet dry matter of 1) .5% sodium chloride, 2) .5% sodium chloride plus .72% sodium bicarbonate, 3) .5% sodium chloride plus .72% sodium bicarbonate, and 4) 1.44% sodium bicarbonate to measure effects on body temperature and respiration rate, milk yield and composition, and blood components that reflect acid-base balance. After data were adjusted for body weight, age, and a covariate based on differences within individuals in the standardization period, they were analyzed with a model that included breed, treatment, week, temperature-humidity index, and interactions. Cow fed sodium bicarbonate and no supplemental sodium chloride had lower body temperatures than the other groups. High sodium and chloride in basal diet and drinking water prevented the large change in dietary amount and ratio of these two electrolytes that treatments were designed to impose. More stringent control of dietary amounts and greater heat stress will be necessary to show effects of these elements on acid-base balance.

Animals↗
PubMed1980

Microvascular surgery.

In situations where existing techniques of reconstruction are inadequate or involve multiple stages, free-flap transfer offers major advantages for the head and neck surgeon. Wider application of free-flap surgery has been inhibited by problems of flap design and graft take. Thrombosis at the microanastomic site, particularly at the venous site, is still a cause of failure. Techniques of anastomosis are of paramount importance. Nakayama ring pin anastomosis is easier to learn, less time-consuming, and shows less early thrombosis that suture techniques. Use of adjunctive pharmacologic agents, such as the tetrahydroimidazo quinazolines, will increase the likelihood of success.

Humans↗
PubMed1979

Cerebrospinal fluid rhinorrhea.

One hundred and nine cases of cerebrospinal fluid rhinorrhea occurring over a ten-year period are reviewed. Experience with the use of fluorescein localization techniques in 45 cases is detailed. The simplicity, easy availability and safety of fluorescein techniques are stressed. Primary rhinologic repair is advocated.

Adenoma, Basophil↗
PubMed1979

Blood glucose and insulin levels, thyroid function, and serology in Ménière's disease, recurrent vestibulopathy, and psychogenic vertigo.

Nineteen patients with unilateral Ménière's disease, 20 with psychogenic dizziness, and 20 with recurrent vestibulopathy (diagnostic criteria in text of paper) were found to have normal five hour glucose tolerance tests, serum thyroxine and effective thyroid indices, and serologic tests for syphilis. Hypothyroidism and hypoglycemia were absent in all groups. An unexplained finding of each diagnostic group was significant increase of fasting blood glucose and insulin levels, and elevated insulin:glucose ratios, compared to a control group. There appears to be no diagnostic indication for performing these chemical and serologic studies in patients with unilateral Ménière's disease, psychogenic vertigo, or recurrent vestibulopathy. Reasons are given to support the view that recurrent vestibulopathy may be a specific vestibular disturbance.

Blood Glucose↗
PubMed1978

Why external rhinoplasty?

The indications for, advantages, and disadvantages of external rhinoplasty are considered from a pragmatic and philosophic point of view. The results in more than 200 patients are analyzed.

Evaluation Studies as Topic↗