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Biomedical subjects

R E Wood

Publications and source records attributed to R E Wood.

At least 19 recordsLinked to original sources
PubMed1992

Anaesthetic management of infants requiring endobronchial argon laser surgery.

Small infants with endobronchial lesions primarily due to traumatic suction catheter injuries are now undergoing argon laser surgery to remove obstructive tissue. Providing an anaesthetic for these infants can be challenging because of the small airways involved which must be shared by the anaesthetist and the surgeon. We have performed 30 argon laser endobronchial surgeries in nine infants. The lungs of the majority of patients were ventilated through a tracheostomy intraoperatively, while the surgeon passed the argon laser fibre through the suction port of a fibreoptic bronchoscope which was passed trans-nasally. Three infants were too small to allow passage of the fibreoptic bronchoscope past an artificial airway. In these patients surgery and ventilation were accomplished through a rigid bronchoscope. Three larger patients without tracheostomies were managed with a modified nasal airway for intraoperative ventilation in conjunction with the fibreoptic bronchoscope.

Airway Obstruction↗
PubMed1992

Sex steroids and vasotocin interact in a female amphibian (Taricha granulosa) to elicit female-like egg-laying behavior or male-like courtship.

Female egg-laying behaviors and male amplectic clasping behaviors in the rough-skinned newt (Taricha granulosa) are similar in that animals clasp an object. In the case of egg-laying, females clasp submerged inanimate objects, whereas in amplexus, males clasp conspecific females. Considering these behavioral similarities and differences, we investigated the possibility that gonadal steroids and vasotocin (AVT) interact to control egg-laying behaviors, as has been shown for the control of amplexus in Taricha males. Intact, gravid T. granulosa females injected ip with AVT, unlike those injected with saline, exhibited egg-laying behaviors and oviposition. In ovariectomy-steroid-implant studies, no saline-injected female exhibited egg-laying behaviors, whereas AVT-injected ovariectomized females exhibited egg-laying behaviors if implanted with estradiol (E2), testosterone, or dihydrotestosterone (DHT), and not if implanted with empty capsules. When given a choice between clasping aquatic vegetation or other females (amplectic clasping), following an AVT injection, unoperated and sham-operated control females and ovariectomized females with E2 implants did not preferentially clasp aquatic vegetation over other females. In contrast, AVT-injected ovariectomized females with DHT implants preferentially clasped other females. Thus, exposure of Taricha females to estrogens or androgens appears to determine whether the AVT-induced clasping is egg-laying or amplectic clasping.

Animals↗
PubMed1992

Endoscopic management of large, postresection bronchopleural fistulae with methacrylate adhesive (Super Glue).

Bronchopleural fistulae that occur following pulmonary resection are usually managed by direct, operative closure. In complex cases, in which the risk of repeat thoracotomy is great, other means may be preferable. We report two patients, one with cystic fibrosis and one with extensive radiation fibrosis post-Askin's tumor, in whom the risk of thoracotomy was considered to be prohibitive. Both had a large fistula between the pleural cavity and a segmental bronchus from the right upper lobe. The cystic fibrosis patient had recurrent massive bleeding from the pleural space. A Teflon catheter was passed through a flexible bronchoscope and Super Glue (butyl or methyl methacrylate) was deposited into the fistula. In both cases, the fistula resolved promptly. One patient developed a large, recurrent granuloma at the site of the fistula requiring endoscopic resection. We believe that tissue adhesive may be a reasonable approach to the management of large bronchopleural fistulas when the risk of operative closure is great.

Adolescent↗
PubMed1992

Acquired lobar emphysema (overinflation): clinical and pathological evaluation of infants requiring lobectomy.

Acquired lobar "emphysema" (overinflation) (ALE) is an increasingly recognized complication of advanced bronchopulmonary dysplasia (BPD). To refine current concepts regarding patient management and pathogenesis, we examined clinical and pathological features of six infants with ALE who did not have obstructing intraluminal lesions and who underwent lobectomy after failing nonoperative management. All had severe neonatal respiratory distress and required prolonged ventilatory support (average, 2 months) with peak inspiratory pressures greater than 30 mm Hg and 100% oxygen. ALE developed between 3 weeks and 20 months of age (median, 5 months), with lobar hyperinflation, atelectasis, and mediastinal shift. Selective bronchial intubation provided only transient benefit. Videobronchoscopy demonstrated no intraluminal obstructing lesions in five patients. In one child, ALE became clinically apparent only after laser excision of an endobronchial cicatrix. All infants had bronchomalacia with the involved lobar bronchus being most severely affected. Ventilation-perfusion scans demonstrated severe impairment of both ventilation and perfusion in the involved lobes. The decision to perform lobectomy was based on clinical parameters and failure of non-operative management. After lobectomy, all children dramatically improved. However, only three of six were alive 2 to 3 years later; one infant died of unrelated causes at 6 weeks; and two died of progressive respiratory insufficiency 13 and 24 months postlobectomy. Microscopic evaluation of the lung demonstrated findings of late-stage BPD with peribronchial and interstitial fibrosis, parenchymal overinflation, and alveolar septal disruption.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchi↗
PubMed1992

B-cell lymphoma presenting as a midfacial necrotizing lesion.

A case of midfacial necrotizing lesion (midline nonhealing granuloma) is reported. Paraffin- and frozen-section immunocytochemistry suggested a tumor of B-cell lineage and was confirmed by Southern blot analysis that disclosed an immunoglobulin heavy chain gene rearrangement with no evidence of T-cell receptor genetic aberration. The tumor was of B-cell lineage despite the tumor site and the angiocentric pattern, which are typically seen with peripheral T cell lymphoma with this presentation.

Aged↗
PubMed1992

Reducing transmitted radiation in dental radiography.

A significant amount of radiation escapes the rear of an image receptor in conventional dental radiographic procedures despite the placement of a lead-containing backing at the rear of the film pack. The purpose of this investigation was to place additional layers of lead on the film pack in an attempt to reduce transmitted radiation to tissues behind the film. Reduction of dose to tissues behind the film causes a reduction in scatter radiation to critical organs such as the thyroid gland and salivary glands. A thermoluminescent lithium fluoride dosimetry system (TLD) was used and calibrated in both the beam of interest and tissue of interest. A tissue-equivalent anthropomorphic phantom was used for dose determination. Successive layers of lead foils were added to the image receptor, and dose was determined for each additional lead foil in the tissues behind the image receptor. Two sets of exposure conditions were used, namely: 70 kVp, 10 mA, and 0.6 s, and 90 kVp, 10 mA, and 0.6 s. The beam-film-patient orientation used was for a first molar bitewing radiographic projection. Four lead layers (three additional foils equalling 3.92 x 10(-3) mm of lead) on the conventional film package resulted in a significant dose reduction. Four layers of lead resulted in a dose less than one-third that of the conventionally shielded package.

Models, Structural↗
PubMed1992

Development of mucociliary transport in the postnatal ferret trachea.

Little is known of the developmental aspects of mucociliary transport. Previous studies have documented that newborn ferret trachea has very few ciliated cells but numerous immature secretory cells in the epithelium and only rudimentary submucosal glands. Rapid and complete maturation occurs in the first postnatal month. This study examines mucociliary transport during this period of rapid maturation. We made direct observations of particle movement across the epithelium of ferret tracheas. No mucus transport could be demonstrated on the first day of life. Transport was discernible, although sporadic and slow, by 7 days and reached adult levels (10.7 +/- 3.7 mm/min) by 28 postnatal days. The emergence of transport capability correlated well with previously described developmental changes in ciliation, mucus secretion, and ion permeability and transport. Threshold mucus transport occurred at 1 wk of age when 20-25% of the surface cells are ciliated. The neonatal ferret appears to be a useful model for assessing integrated epithelial structure-function relationships that are important not only during early development but also during repair after airway injury involving deciliation.

Aging↗
PubMed1992

Flexible bronchoscopy in infants.

Flexible bronchoscopy is a useful diagnostic and sometimes therapeutic tool in small or premature infants, just as it is in older children. Special diligence is required to monitor the child before, during, and after the procedure, and to choose the appropriate instrument. Procedures must be completed rapidly, because most premature infants will be essentially apneic during the time the tip of a flexible bronchoscope is below the glottis. For some procedures, a rigid instrument may be a better choice, although for the majority of diagnostic procedures, flexible instruments are entirely satisfactory.

Bronchoscopes↗
PubMed1991

Postradiation dental extractions without hyperbaric oxygen.

This study examined the incidence of osteoradionecrosis after tooth extraction with low-epinephrine or epinephrine-free, nonlidocaine local anesthetics and conservative surgical techniques. Estimates of the absorbed radiation dose on irradiated alveolar bone were made by reviewing radiotherapy records. This investigation included 72 patients ranging in age from 22 to 80 years (median 57.4 years). We removed 449 teeth. Analysis of radiotherapy check films revealed that only 196 teeth (44%) were included within the treatment volume. The median prescribed tumor dose was 50 Gy (range 25 to 84 Gy) in 20 fractions (range 10 to 37), with a median dose per fraction of 2.5 Gy (range 1.88 to 3.14 Gy). Follow-up time ranged from 68 days to 19.3 years (median 4.8 years). No instances of osteoradionecrosis occurred as a result of dental extraction with this conservative method.

Adult↗
PubMed1991

The leaded apron revisited: does it reduce gonadal radiation dose in dental radiology?

A tissue-equivalent anthropomorphic human phantom was used with a lithium fluoride thermoluminescent dosimetry system to evaluate the radiation absorbed dose to the ovarian and testicular region during dental radiologic procedures. Measurements were made with and without personal lead shielding devices consisting of thyroid collar and apron of 0.25 mm lead thickness equivalence. The radiation absorbed dose with or without lead shielding did not differ significantly from control dosimeters in vertex occlusal and periapical views (p greater than 0.05). Personal lead shielding devices did reduce gonadal dose in the case of accidental exposure (p less than 0.05). A leaded apron of 0.25 mm lead thickness equivalent was permeable to radiation in direct exposure testing.

Gonads↗
PubMed1991

Surgical applications of ultrathin flexible bronchoscopes in infants.

Ultrathin flexible bronchoscopes with controlled distal angulation allow the conventional diagnostic examination of the lower airways of even the smallest infants. These instruments may be passed through small endotracheal or tracheostomy tubes while ventilation is maintained. It is thus possible, under direct visualization, to control the manipulation of surgical instruments where they could not otherwise be seen, or to study airway dynamics and anatomy intraoperatively without extubating the patient.

Airway Obstruction↗
PubMed1991

Skin exposure and thyroid dose distribution using niobium filtration.

A thermoluminescent dosimetry system was utilized to investigate how much the radiation dose is reduced through the addition of a niobium-based accessory filter to an X-ray unit's conventional aluminum filter. A two-bitewing series was exposed in a tissue-equivalent human phantom. The skin exposures from an X-ray beam with the added niobium filter and a beam with the aluminum filter alone were measured and compared. Thyroid dose distribution was also measured and similarly compared. Utilization of the niobium filter resulted in a significant reduction in skin exposure (p less than 0.001) of 14.8 per cent. Thyroid dose was not lessened by using the niobium filter, however. In fact, in one region of the thyroid it increased significantly.

Filtration↗
PubMed1990

Model systems for learning pediatric flexible bronchoscopy.

Considerable practice is necessary to develop the skills essential to successful and safe performance of flexible bronchoscopy, especially in pediatric patients. We review a number of model systems, both mechanical and living, for learning and maturing bronchoscopic skills. For each of the animal models (canine, feline, leporine, and simian), the relevant anatomy and anesthetic techniques as well as the relative advantages and disadvantages of each model are discussed.

Anesthesia↗
PubMed1990

Ewing's tumor of the jaw.

Previous reports have focused on the fact that laminar periosteal new bone is a common radiologic sign of Ewing's sarcoma of the jaws. Critical analysis of the literature does not lead to this conclusion. A case is reported and radiologic appearances described. A review of the literature shows striking clinical and radiologic similarities to osteogenic sarcoma of the jaws. A differential radiologic interpretation of Ewing's sarcoma of the jaws is offered.

Child↗