Biomedical subjects

T V McCaffrey

Publications and source records attributed to T V McCaffrey.

At least 127 records · Page 7Linked to original sources

PubMedDate not supplied

Laryngeal regulation of airway resistance. I. Chemoreceptor reflexes.

The resistance of the larynx to airflow was measured during hypercapnia, hypoxemia, and stimulation of peripheral chemoreceptors by sodium cyanide and phenyl diguanide in 15 dogs anesthetized with alpha-chloralose (80 mg/kg). Laryngeal airway resistance (R1x) was obtained by measuring the pressure difference between the subglottic region and the mouth while a constant flow of humidified air was passed through the larynx. During spontaneous respiration, R1x varies with the phase of the respiratory cycle: R1x is high during expiration (mean +/- SEM = 0.79 +/- 0.19 cm H2O/L/sec) and falls just before inspiration (0.49 +/- 0.14 cm H2O/L/sec) and remains low until the end of inspiration. Hypercapnia, hypoxemia, and chemoreceptor stimulation each stimulated respiration and simultaneously decreased R1x during both inspiration and expiration. Chemoreceptor stimulation with phenyl diguanide (100 microgram/kg) and sodium cyanide (100 microgram/kg) produced similar decreases in R1x whether injected into the right atrium or left ventricle, indicating that these agents are not stimulating pulmonary receptors. The decrease in R1x during stimulation of chemoreceptors will decrease the work of ventilation. This study suggests that the control of ventilation involves the active regulation of the resistance of the laryngeal airway.

Airway Resistance↗

PubMedDate not supplied

Laryngeal regulation of airway resistance. II. Pulmonary receptor reflexes.

The response of laryngeal airway resistance to pulmonary receptor stimulation was studied in 20 mongrel dogs anesthetized with alpha-chloralose (80 mg/kg). Stimulation of pulmonary stretch receptors by lung inflation inhibited the phasic variation of laryngeal resistance during respiration and produced a sustained reduction of laryngeal resistance, which was related to lung inflation pressure. Stimulation of pulmonary J-receptors with capsaicin produced apnea and a large increase in laryngea resistance. Capsaicin produced this reflex when injected into the pulmonary circulation but not when injected into the systemic circulation. Irritant receptor stimulation with histamine hydrochloride produced tachypnea and a reduction in inspiratory laryngeal resistance. Pulmonary receptor reflexes were abolished by dividing the vagus nerves distal to the origin of the recurrent laryngeal nerves. Laryngeal reflexes may be important in the regulation of respiration and the production of physiologic and pathologic alterations in pumonary function.

Airway Resistance↗

PubMedDate not supplied

Age-related responses of laryngeal airway resistance to peripheral and central chemoreceptor stimulation.

Laryngeal airway resistance was measured in anesthetized dogs ranging in age from one day to adult during central and peripheral chemoreceptor stimulation by hypoxia and hypercapnia. Chemoreceptor-mediated regulation of airway resistance was found to be qualitatively similar in all age groups; however, there was a progressive increased sensitivity to both hypoxia and hypercapnia with increasing age. The reduced sensitivity of the laryngeal airway to hypoxic and hypercapnic stimulation in the young animal may predispose the young animal to airway obstruction during periods of hypoxia or hypercapnia. This may bear some relevance to the etiology of certain cases of sudden infant death syndrome.

Aging↗

PubMedDate not supplied

Repair of traumatic cervical esophageal stenosis using microvascular free jejunum transfer.

Three cases of nonneoplastic stricture of the cervical esophagus and pharynx repaired by free jejunal transfer are reported. This technique permits repair of various circumferential defects of the pharynx and esophagus in a single stage without compromising laryngeal function. None of the patients required subsequent dilatation to restore satisfactory swallowing.

Adolescent↗

PubMedDate not supplied

The nasal valve: a rhinomanometric evaluation of maximum nasal inspiratory flow and pressure curves.

The nasal valve is defined as the region of the nasal airway bounded by the caudal end of the upper lateral cartilages and the nasal septum. During inspiration this region of the nasal airway may collapse and produce a marked increase in nasal airway resistance. To define the function of this region, measurements of the nasal airway resistance in 38 subjects were performed. Using anterior mask rhinomanometry, right and left total nasal resistance, right and left upstream nasal resistance, right and left downstream nasal resistance, and right and left transmural collapsing pressure of the nasal valve were measured. Subjects who complained of nasal obstruction and had anatomical evidence of anterior nasal deformity showed a reduced level of transmural closing pressure compared with subjects complaining of no airway obstruction or those with anatomical evidence of posterior nasal deformity. This suggests that premature collapse of the nasal valve due to inadequate cartilaginous support is an important factor in producing nasal airway obstruction in individuals with anterior nasal septal abnormality. In those individuals with nasal airway obstruction and anatomical evidence of posterior nasal deformity, downstream nasal resistance was elevated compared with the asymptomatic group and the group with anatomical evidence of anterior nasal septal deformity. This paper demonstrates that premature collapse of the nasal valve is responsible for the symptom of nasal obstruction in many patients with anterior nasal septal deformity.

Air Pressure↗

PubMedDate not supplied

Effect of radiotherapy on the outcome of pharyngeal reconstruction using free jejunal transfer.

Eighteen patients had free jejunal reconstruction of the pharynx and cervical esophagus following pharyngoesophagectomy for malignant tumors. Four patients had no radiation therapy, four had postoperative radiotherapy, and ten had preoperative radiotherapy. Comparison of complication rates indicated no increased risk of complication in patients receiving 6,100 to 6,400 rad of postoperative radiotherapy. Patients having preoperative radiotherapy had a higher incidence of graft failure due to vessel thrombosis, suggesting that radiation endarteritis may increase the risk of graft failure.

Adult↗

PubMedDate not supplied

Head and neck manifestations of relapsing polychondritis: review of 29 cases.

This review of 29 patients with relapsing polychondritis seen at the Mayo Clinic between 1962 and 1976 emphasizes the head and neck manifestations of the disease and the role of the otolaryngologist in its diagnosis and treatment. The major clinical features included inflammation of the pinna, eye involvement, nasal cartilage involvement, laryngotracheal involvement, arthropathy, hearing loss, costal chondritis, and fever. The erythrocyte sedimentation rate was often elevated, and mild anemia was not uncommon.

Adolescent↗

PubMedDate not supplied

Dermoid cysts of the nose: review of 21 cases.

Twenty-one cases of histologically confirmed dermoid cysts of the nose are reviewed. The sites involved were the dorsum (18), septum (5), glabella (2), nasal tip (2), and columella (1), with several patients having multiple sites of involvement. Bony or cartilaginous destruction occurred in 14 patients (67%). A sinus tract was evident in ten patients (48%). Complete excision of these lesions is necessary for prevention of recurrence. The differential diagnosis includes hemangiomas, gliomas, encephaloceles, epidermoid cysts, neurofibromas, and lipomas.

Adolescent↗

PubMedDate not supplied

Otologic manifestations of Wegener's granulomatosis.

Review of 112 patients with Wegener's granulomatosis showed that 21 (19%) had ear involvement. Conductive deafness, which was present in all 21 patients, was due to serous middle ear fluid, suppurative otitis media with thickening of the tympanic membrane, perforation of the tympanic membrane, or granulation tissue in the middle ear space. Nine patients also had sensorineural hearing loss. Sensorineural hearing loss was improved in five of the nine patients after control of the disease with prednisone and cyclophosphamide.

Adult↗

PubMedDate not supplied

Response of laryngeal airway resistance to chemoreceptor stimulation: effect of pulmonary afferent denervation.

The response of laryngeal airway resistance to chemoreceptor stimulation was measured before and after vagotomy in ten anesthetized dogs. With the vagus nerves intact, stimulation of chemoreceptors produced a decrease in both inspiratory and expiratory laryngeal resistance. After bilateral vagotomy below the origin of the recurrent laryngeal nerves, stimulation of chemoreceptors produced a smaller decrease in inspiratory laryngeal resistance and an increase in expiratory laryngeal resistance. We concluded that pulmonary afferent input to the respiratory neurons maintains a low airway resistance during chemoreceptor stimulation.

Afferent Pathways↗

PubMedDate not supplied

Evaluation of the thyroid nodule.

BACKGROUND: Clinically detectable thyroid nodules occur in up to 4% of the population in the United States. With ultrasound, nodules may be found in up to 50% of those over 50 years of age. METHODS: The author reviews his own experience as well as that of others to define a sound clinical approach to the differential diagnosis and detection of thyroid cancer. RESULTS: Prior neck irradiation is a risk factor for thyroid malignancy. The association of a thyroid nodule with enlarged lymph nodes or fixation of the nodule to strap muscles or the trachea suggests malignancy. A diffusely multinodular gland is usually benign. CONCLUSIONS: Thyroid function tests rarely help a differential diagnosis. Fine-needle aspiration is the "gold standard" for diagnosis. Tiny "incidentalomas" are often followed with repeat monitoring for change of size or character.

Biopsy, Needle↗

PubMedDate not supplied

The correlation between ciliary ultrastructure and ciliary beat frequency in experimental chronic sinusitis.

Ciliary ultrastructural abnormalities secondary to chronic sinusitis may cause abnormal mucociliary transport clearance. We examined the relationship between anatomic abnormalities of ciliary ultrastructure secondary to chronic sinusitis and ciliary beat frequency (CBF) before and after middle meatal antrostomy (MMA) in rabbits. Ultrastructural abnormalities of cilia included absence of axoneme membrane, blebs of the axoneme membrane, compound cilia, and ciliary orientation. Two groups of rabbits were studied: Uninfected (group A control, n = 3) and infected (group B, n = 10); 10(8) CFU S. pneumoniae were used to infect the animals in group B after sinus ostial occlusion and chronic sinusitis developed. After 6 weeks with infection, 6 of 10 group B animals underwent MMA and were restudied 6 weeks later. Uninfected animals had mean CBF = 11.75 Hz. Animals with chronic sinusitis had mean CBF = 8.5 Hz (p < 0.05). Six weeks after MMA, mean CBF = 11.82 Hz. This was not different from control. There were significant changes in ciliary ultrastructure when uninfected and infected rabbits were compared. These changes were reversed with MMA. Changes in ciliary ultrastructure correlated significantly with changes in CBF for all animals. Abnormalities in ciliary ultrastructure may account for the abnormal mucociliary transport clearance seen in chronic sinusitis in rabbits.

Animals↗

PubMedDate not supplied

A combined, minimally invasive transnasal approach to the sella turcica.

The increasing use of endonasal techniques and a new 3-dimensional CT-guided imaging system have allowed us to develop a combined, minimally invasive endonasal approach to the pituitary gland. Thus far, more than 30 patients have undergone an endonasal transsphenoidal approach to the sella using a combined endoscopic approach, with additional selective use of the Instatrak CT-guided imaging system for real-time imaging. Our current technique involves obtaining a preoperative CT using a plastic head frame with registration markers. By using this head frame intraoperatively, real-time localization with CT images in axial, coronal, and sagittal planes can be performed. Using endoscopic techniques and a Papavero-Caspar speculum, the sella is exposed. A combined approach using endoscopes, the operating microscope, and real-time localization is undertaken to expose and resect tumors. We have encountered minimal associated complications in our series, and this method has been progressively modified to improve exposure and safety. Because we are able to visualize the sella without a sublabial incision or septal resection, we have nearly eliminated the need for nasal packing, reduced the average hospital stay to 2.5 days, and improved patient satisfaction.

Adolescent↗

PubMedDate not supplied

Transnasal endoscopic approach to the sella turcica.

The transseptal/transsphenoidal approach to the pituitary gland has been the most commonly used approach for resection of pituitary adenomas for the last 50 years. This procedure has a low morbidity and provides direct midline access to the sella and pituitary gland. Recent advancements in endoscopic surgery, however, suggest that a lower morbidity approach to the sella would be possible via transnasal endoscopic route. Prior reports have confirmed effectiveness of this approach to the pituitary gland and we report here an early series of endoscopic transnasal pituitary surgery from our institution. We report seven cases of transnasal endoscopic pituitary surgery. Our technique consists of endoscopic exposure of the sphenoid ostium unilaterally, excision of the posterior septum anterior to the rostrum of the sphenoid sinus with resection of the sphenoid rostrum for bilateral exposure of the sphenoid sinus. A specially designed nasal speculum is positioned to displace the posterior septum and lateralize the middle turbinates, permitting direct midline exposure of the sphenoid sinus and sella. We have progressively modified the technique over the seven cases that we present and will discuss our specific instrumentation, indications, and technique for this procedure. We have encountered one cerebrospinal fluid leak in this series. Patient satisfaction has been high and hospitalization is less than with the conventional transseptal approach, averaging 1 day. Our impression is that the transnasal endoscopic approach to pituitary adenomas is a safe technique with reduced morbidity permitting shortened hospital stay.

Adenoma↗

PubMedDate not supplied

Muscarinic ciliostimulation requires endogenous prostaglandin production.

Prostaglandin E2 (PGE2) is a known modulator in upper airway ciliary activity and may be involved in the transduction of the muscarinic acetylcholine receptor signal. We studied the in vitro effects of muscarinic ciliostimulation on ciliary beat frequency (CBF) and PGE2 in human adenoid explants to determine whether PGE2 production is an essential step in the signal transduction mechanism. Methacholine applied to adenoid explants significantly increased ciliary beat frequency. This effect was blocked by the application of diclofenac, a cyclooxygenase inhibitor. Using radioimmunoassay, PGE2 production was measured during ciliostimulation with methacholine. Methacholine produced a significant increase in production in PGE2 during ciliostimulation. The roles of phospholipase C and phospholipase A2 in prostaglandin production were investigated by inhibiting these enzymes. D609, a phospholipase C inhibitor, significantly inhibited ciliary beat frequency increase and PGE2 production during methacholine stimulation. However, PACOCF3, a phospholipase A2 inhibitor, did not block ciliary beat frequency increase or PGE2 production in response to methacholine. These data show that phospholipase C is required for PGE2 production and ciliostimulation.

Acetylcholine↗

PubMedDate not supplied

Response of nasal airway resistance to hypercapnia and hypoxia in the dog.

Nasal airway resistance was calculated in 9 anesthetized mongrel dogs by measuring the pressure difference across the nasal airway while a continuous flow of humidified air was passed through the upper airway. Hypercapnia produced a significant decrease in nasal airway resistance (P less than 0.05, Wilcoxon signed-rank test), which was proportional to the Paco2 over the range of 40 to 70 torr. Hypoxia produced a decrease in nasal airway resistance only when there was severe depression of Pao2. Direct stimulation of peripheral chemoreceptors by intravenously administered NaCN (100 microgram/kg) resulted in a significant decrease in nasal airway resistance (P = 0.06, Wilcoxon signed-rank test). Interruption of the cervical sympathetic trunk bilaterally abolished or reversed the response of the nasal airway resistance to hypercapnia and to NaCN. The study indicates that the nasal airway can modify airway resistance in response to respiratory stimuli and that this reflex is mediated by the sympathetic nervous system.

Airway Resistance↗

PubMedDate not supplied

alpha-Adrenoceptor-mediated secretion from the anterior nasal glands of the dog.

The secretion of fluid from the anterior nasal glands in pentobarbital-anesthetized dogs was measured by absorption on filter papers that were weighed before and after insertion into the nose. The secretion was stimulated by the local effects of drugs present on the dried filter paper. Methacholine evoked a dose-related secretion that could be reduced by atropine. Phenylephrine caused a scanty but measurable secretion in a dose that is used in topical nasal decongestants. When this alpha-adrenoceptor-stimulating drug was tested in combination with different doses of methacholine, a large increase in secretion was obtained over that with methacholine used alone. The increased secretion evoked by the combination was abolished by the alpha-adrenoceptor blocking drug phentolamine.

Animals↗

PubMedDate not supplied

Endoscopic transnasal pituitary surgery: report on 180 cases.

The endoscopic transnasal approach is an evolving technique for treating lesions in the sella turcica. Since this method was introduced at our institution 4 years ago, the majority of transsphenoidal procedures are performed with it. The records of all patients having endoscopic transnasal hypophysectomy at the Mayo Clinic during the last 4 years were reviewed retrospectively. The criteria analyzed were safety, functional and cosmetic outcome, and complications. During the 4-year period, the operative procedure was modified to improve operative exposure and safety. The results of our review showed a significant decrease in length of hospital stay, reduced operative time, reduced need for nasal packing, and elimination of a sublabial incision. The complication rate was equivalent to that reported for the traditional transseptal transsphenoidal approach. As the neurosurgeons at our institution gained experience with this approach, an increasing number of pituitary microadenomas were resected safely and successfully. In addition, because of the limited septal dissection, this approach is particularly helpful for revision operations. This approach also can be used for the full range of pituitary lesions and in conjunction with adjunctive techniques, including frontal craniotomy and gamma-knife irradiation. Currently, the endoscopic transsphenoidal approach is the method preferred for surgically treating pituitary lesions in adults at our institution.

Adenoma↗