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Biomedical subjects

T J Sullivan

Publications and source records attributed to T J Sullivan.

At least 199 records · Page 11Linked to original sources
PubMed1969

Relationship between the uptake, binding and pharmacological action of procaine in the isolated heart.

1. The uptake, efflux and pharmacological actions of procaine hydrochloride were studied on isolated hearts of female guinea-pigs. The hearts were perfused with Krebs solution containing (14)C-procaine (0.1-500 mug/ml.) by the Langendorff technique at 37 degrees C, using a constant flow pump. Hearts and cardiac effluent were assayed for procaine by liquid scintillation spectrometry.2. Accumulation of procaine did not appear to involve active transport mechanisms for the following reasons. The rate of procaine uptake was most rapid at the highest perfusion concentration (500 mug/ml.), when it was three times faster than at the lowest concentration (0.1 mug/ml.); it was not affected by lowering the temperature to 3 degrees C. The ratio of the concentration of procaine in the heart to the concentration in the perfusing fluid decreased with increasing concentration in the perfusion fluid.3. When the efflux of (14)C-procaine from hearts previously perfused with procaine-containing Krebs solution for 10 min was compared with the efflux of (14)C-inulin, the patterns of efflux of both compounds were similar, and showed at least two exponential components. At the highest concentration of procaine (500 mug/ml.) the efflux of procaine was more rapid than that of inulin.4. A relationship was found between the pharmacological action of procaine, the rate of uptake and the level of procaine in the heart. When the procaine-containing perfusion fluid was changed to a procaine-free solution, the heart rate increased rapidly, and there was a rapid decline in the levels of procaine in the hearts.5. It is concluded that guinea-pig hearts accumulate procaine by a passive diffusion process, and that the pattern and rate of efflux indicate that the drug is loosely bound. If it is permissible to extrapolate from these findings to the antiarrhythmic effect in man, the short duration of its action may be due to loose binding rather than to rapid metabolic inactivation.

Animals↗
PubMedDate not supplied

A study of the interaction between dirithromycin and astemizole in healthy adults.

The effect of a standard regimen of dirithromycin, a macrolide antibiotic, on the single-dose pharmacokinetics of the H (1) receptor blocker astemizole was evaluated in a sample of 18 healthy young adults (nine males and nine females). The study was conducted in a two-way cross-over fashion after the subjects had been randomly given either dirithromycin (two 250 mg tablets) or placebo (two tablets) every morning for 10 days. On the morning of the fourth dose of either dirithromycin or placebo each subject ingested a single 30-mg oral dose (three 10-mg tablets) of astemizole. The disposition kinetics of both astemizole and its major metabolite, N-desmethylastemizole, were characterized after measuring the concentrations of both analytes in the serum fraction of serial blood samples collected for 14 days after the astemizole dose. In addition, corrected QT (QT(c) ) intervals were estimated from electrocardiogram rhythm strips that were run 24 hours prior to the astemizole dose, 12 hours after the astemizole dose, and after the last treatment (dirithromycin or placebo) dose in both study periods. Pharmacokinetic parameters that were measured for both astemizole and N-desmethylastemizole during each treatment were: C(max), t(max), AUC (0-infinity), CL(oral), half-life, and volume of distribution (V). None of the parameters for N-desmethylastemizole was different when comparing data by ANOVA from the dirithromycin treatment period with that of the placebo treatment period. On the other hand, during dirithromycin treatment astemizole CL(oral) was 34% slower, volume of distribution was 24% larger, and half-life was 84% longer. Generally, all QT ( c ) intervals did not appear to be affected by dirithromycin treatment. The changes in astemizole kinetics could not be attributed to its N-demethylation since the dispositional kinetics of N-desmethylastemizole were unaffected by dirithromycin. Therefore, it is difficult to ascertain the clinical significance of the changes in astemizole kinetics. Since there were no significant differences for mean QT(c) intervals and no effect of dirithromycin treatment on N-desmethylastemizole kinetics, it is unlikely that a standard regimen of dirithromycin would place a patient taking astemizole at an increased risk of torsade de pointes or related ventricular arrhythmias.

Adolescent↗
PubMedDate not supplied

Biomechanics of baseball pitching. A preliminary report.

Fifteen professional major league pitchers were filmed with high speed cinematography. One hundred forty-seven pitches were analyzed using an electromagnetic digitizer and a microcomputer. Three phases of throwing were studied: cocking, acceleration, and follow-through. The cocking phase is the period of time between the initiation of the windup and the moment at which the shoulder is in maximum external rotation. This phase occurs in approximately 1500 ms, and the shoulder is brought into an extreme position of external rotation. The acceleration phase and the initial stages of the follow-through phase produce extraordinary demands on the shoulder and elbow. The acceleration phase begins with the throwing shoulder in the position of maximum external rotation and terminates with ball release. This phase occurs in approximately 50 ms, and peak angular velocities averaging 6,180 deg/sec for shoulder internal rotation and 4,595 deg/sec for elbow extension were measured. The follow-through phase begins at ball release and continues until the motion of throwing has ceased. This phase occurs in approximately 350 ms.

Acceleration↗
PubMedDate not supplied

General anesthesia with endotracheal intubation for cryotherapy for retinopathy of prematurity.

We present a technique for treating retinopathy of prematurity (ROP) with cryotherapy under general anesthesia, administered and monitored by a neonatologist, with endotracheal intubation in the neonatal intensive care unit that avoids the serious systemic complications associated with the administration of local anesthetics. Although no significant complications arose in this series, having the intubated infant monitored by trained neonatology staff allows appropriate management should complications arise. We have used this technique to treat 20 eyes with threshold ROP. The mean time to extubation was 40.2 hours. The systemic status and discharge from the neonatal intensive care unit were not influenced by the general anesthesia. This technique allows quick and accurate application of the cryotherapy in a stable and controlled setting. We recommend that physicians consider cryotherapy under general anesthesia with endotracheal intubation for infants with ROP. This technique allows ROP to be treated adequately with minimal risk to the infant.

Anesthesia, General↗
PubMedDate not supplied

Management of patients allergic to antimicrobial drugs.

Allergic reactions to antimicrobial drugs cause significant morbidity in approximately 1% of treated patients. Those who express allergic reactions to antimicrobial drugs or who are at increased risk of reacting also can present difficult diagnostic and management problems. Recent studies suggest that patients who have expressed allergic reactions to antimicrobial drugs in the past or who are the offspring of antimicrobial drug-allergic parents are at increased risk of antimicrobial drug allergy. This propensity to antimicrobial drug allergy is not restricted to specific classes of drug or to specific patterns of allergic reactions. The concept that antimicrobial drug allergy often is a recurrent disease rather than an isolated event has generated new approaches to the comprehensive management of high-risk patients. This concept also has suggested new areas for investigation that may provide fundamental new insights into why some persons express immune responses to haptens and others do not.

Anti-Infective Agents↗
PubMedDate not supplied

The optic disc in Leber congenital amaurosis.

The typical fundus appearance in Leber congenital amaurosis (LCA) in infancy is normal. Later in childhood, clinical heterogeneity develops and a variety of fundal abnormalities may be seen. These commonly include optic atrophy, retinal arteriolar attenuation, and a variety of pigmentary changes. We retrospectively reviewed the optic disc findings of 77 patients with LCA whom we had examined to confirm our clinical impression that the optic discs are frequently normal. Age at examination ranged from infancy to the fourth decade. The optic discs were normal in 53 (69%) of the 77 patients examined; 18 (23%) had varying degrees of optic atrophy; 2 (3%), pseudopapilledema; and 1 (1%), grey discs. The optic discs could not be seen in 3 (4%) patients. We conclude that the optic discs are frequently normal in appearance, even in older patients with LCA.

Adolescent↗
PubMedDate not supplied

Oculomotor nerve palsies in children.

Fifty-four patients with oculomotor nerve palsy who presented over a 21-year period at our institution were reviewed retrospectively. There were 38 isolated third nerve lesions, and 16 with additional cranial nerve involvement. Eleven cases were congenital in origin, and 43 were acquired. Of the acquired group, 31 were traumatic, 7 infection-related, 3 attributed to migraine or other vascular causes, and 2 neoplastic. Average follow up was 36 months. The congenital lesions were predominantly right-sided; amblyopia, although common, responded well to treatment. Trauma and bacterial meningitis accounted for more cases of isolated oculomotor nerve palsy than seen in the previous literature. In distinct contrast to the adult population, no cases of diabetes, posterior communicating artery aneurysms, metastatic tumors, or pituitary lesions were found.

Adolescent↗
PubMedDate not supplied

The ocular manifestations of the Sturge-Weber syndrome.

Sturge-Weber syndrome (SWS) is a rare neuro-oculocutaneous disorder. The ocular component manifests as glaucoma and vascular malformations of the conjunctiva, episclera, choroid, and retina. The authors reviewed the records of and recalled for examination 51 consecutive patients with a diagnosis of SWS seen at The Hospital for Sick Children, Toronto, Ontario, Canada, from 1980 to 1991. Of the 51 patients, 36 (71%) had glaucoma, 26 experienced onset before 24 months of age and the remainder after 66 months of age, 35 (69%) had conjunctival or episcleral hemangiomas, and 28 (55%) had choroidal hemangiomas, which were bilateral in 12 patients. Other ocular manifestations (retinal vascular tortuosity, iris heterochromia, retinal detachment, and strabismus) also occurred. Thirty-four of 51 (67%) glaucomatous eyes had a final visual acuity of 20/40 or better, or central, steady, and maintained fixation in each eye.

Child↗
PubMedDate not supplied

New arrangements, new scrutiny. The IRS reconsiders hospital-physician relationships at tax-exempt facilities.

The pressure to maintain adequate operating margins has forced many not-for-profit hospitals to adopt more overtly competitive behavior than they have in the past. However, in struggling to remain economically viable, these facilities should carefully avoid actions that would threaten their tax-exempt status. Not-for-profit facilities should be particularly careful that their arrangements with physicians, which often appear designed to increase referrals, do not violate the criteria according to which the Internal Revenue Code extends tax exemption to charitable organizations. Section 501(c)(3) of the code exempts organizations "no part of the net earnings of which inures to the benefit of any private shareholder or individual." According to this provision, "insiders" (i.e., those with a personal interest in or opportunity to influence organization activities from the inside) are entitled to no more than reasonable payment for their goods or services. The Internal Revenue Service (IRS) takes the position that, as employees or individuals having a close professional working relationship with a hospital, physicians are insiders. Thus a hospital that pays physicians what the IRS judges to be more than fair market value for services (or charges physicians less than fair market value for office rental) may find its exemption in jeopardy. If not-for-profit hospitals want to maintain their tax-exempt status, they must be certain the arrangements they enter into with physicians truly further their exempt purpose: to promote the health of the community.

Charities↗
PubMedDate not supplied

Partnership for health care. An academic nursing center in a rural community college.

Academic nursing centers, owned and administered by schools of nursing, provide ambulatory care in settings in which nurses are both health care providers and clinic managers. Such centers are growing in number within the United States (1,2). In contrast to academic health centers that are based on a medical model, they "give the client direct access to professional nursing services ... using nursing models of health" (3). Academic nursing centers provide accessible and affordable health care services to a variety of clients, including women and children, the elderly, the homeless, minorities, and low-income and underserved persons. They are based in diverse settings--schools of nursing, senior or neighborhood centers, public housing projects, storefronts, churches, schools, and mobile vans--and in some instances, they serve as home care providers (4). They have in common their ownership by schools of nursing.

Adolescent↗