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Biomedical subjects

R Cleveland

Publications and source records attributed to R Cleveland.

12 recordsLinked to original sources
PubMed2001

Chronic radiographic lung changes in children with vertically transmitted HIV-1 infection.

OBJECTIVE: We prospectively studied children with and without maternally transmitted HIV-1 infection born to mothers infected with HIV-1 to determine the incidence of chronic radiographic lung changes (CRC) and to correlate these changes with clinical assessments. SUBJECTS AND METHODS: Between 1990 and 1997, we scored 3050 chest radiographs using a standardized form. Group I children (n = 201) were HIV-1-infected at enrollment. Group II children (n = 512) were enrolled prenatally or before 28 days postpartum and subsequently subdivided into group IIa (n = 86), children identified as HIV-1-infected; and group IIb (n = 426), those who were HIV-1-uninfected. CRC were defined as parenchymal consolidations or nodular disease lasting 3 months or more or increased bronchovascular markings or reticular densities lasting 6 months or more. Morbidity was assessed by CD4 counts, viral load, the presence of low oxygen saturation, wheezing, tachypnea, crackles, and clubbing. RESULTS: The cumulative incidence of chronic radiographic lung changes in HIV-1-infected children was 32.8% by 4 years old, with increased bronchovascular markings or reticular densities being most common. Chronic changes were associated with lower CD4 cell counts and higher viral loads. Resolution of these chronic changes was associated with decreasing CD4 cell counts but not with lower rates of clinical findings, viral load, or difference in survival. CONCLUSION: With increased survival, CRC are becoming more common. The resolution of these changes may indicate immunologic deterioration rather than clinical improvement.

AIDS-Related Opportunistic Infections↗
PubMed1996

Radio frequency electromagnetic exposure: tutorial review on experimental dosimetry.

Radio frequency (RF) dosimetry is the quantification of the magnitude and distribution of absorbed electromagnetic energy within biological objects that are exposed to RF fields. At RF, the dosimetric quantity, which is called the specific absorption rate (SAR), is defined as the rate at which energy is absorbed per unit mass. The SAR is determined not only by the incident electromagnetic waves but also by the electrical and geometric characteristics of the irradiated subject and nearby objects. It is related to the internal electric field strength (E) as well as to the electric conductivity and the density of tissues; therefore, it is a suitable dosimetric parameter, even when a mechanism is determined to be "athermal." SAR distributions are usually determined from measurements in human models, in animal tissues, or from calculations. This tutorial describes experimental techniques that are used commonly to determine SAR distributions along with the SAR limitations and unresolved problems. The methods discussed to obtain point, planar, or whole-body averaged SARs include the use of small E-field probes or measurement of initial rate of temperature rise in an irradiated object.

Animals↗
PubMed1996

Radiographic appearance of follicular bronchitis in children.

OBJECTIVE: The purpose of this study was to present the first radiographic description of a newly described disease in children, follicular bronchitis. MATERIALS AND METHODS: We retrospectively reviewed the medical history and radiographs of eight children with biopsy evidence of follicular bronchitis. RESULTS: All eight infants had findings on initial radiographs that were consistent with viral inflammatory disease. The clinical features of follicular bronchitis started by 6-8 weeks old and peaked between about 2 and 3 years old. After several months of the disease, the infants' radiographs showed a more obvious interstitial pattern. When these children were approximately 3 years old, the radiographic findings began to return to normal. Four children have been followed up for at least 8 years. By that age, the clinical symptoms of respiratory disease have disappeared. All four children tested after they were 8 years old had abnormal results of pulmonary function tests. CONCLUSION: The combination of unique clinical features associated with the radiographic appearances we describe should allow radiologists to suggest the diagnosis of follicular bronchitis.

Bronchitis↗
PubMed1992

Radiologic localization of the laryngeal mask airway in children.

In the absence of data on the anatomic localization of the cuff of the laryngeal mask airway (LMA) in children, radiologic images were obtained from 50 infants and children (aged 1 month to 15 yr) undergoing diagnostic radiologic procedures during halothane and N2O:O2 anesthesia. In 46 patients, the cuff of the LMA was in the pharynx and covered the laryngeal opening. The upper (proximal) section was adjacent to the base of the tongue at the level of C1 or C2 vertebrae pushing the tongue forward and its lower (distal) end was in the inferior recesses of the hypopharynx at the levels of C4 to T1 vertebrae. The cuff of LMA at this position between the base of the tongue above the epiglottis and below the laryngeal opening, covered the laryngeal aperture, forming a low pressure seal at the entrance of the larynx. In 37 of these 46 patients, a posterior deflection of the epiglottis was noted (< 45 degrees), and in only 9, the epiglottis was in the anatomic position. In four patients, the cuff of the LMA was located in the oropharynx. No correlation was found between the size of the LMA and the position of the epiglottis with respect to end-tidal CO2, respiratory rate, or the leak pressures. The size of the LMA, its anatomic location, and the position of the epiglottis had no significant effect on the respiratory parameters of spontaneously breathing children.

Adolescent↗
PubMed1990

Randomized double-blind study of intravenous tocainide versus lidocaine for suppression of ventricular arrhythmias after cardiac surgery.

To compare the therapeutic efficacy and safety of intravenous tocainide with that of intravenous lidocaine in patients with ventricular arrhythmias after cardiac surgery, 25 patients were randomized to either agent in a double-blind manner. Tocainide was given in 16 patients as a 250 mg bolus followed by a loading infusion of 500 mg over 15 minutes and a maintenance infusion of 33.3 mg/min. Lidocaine was administered in 9 patients as a 100 mg bolus followed by a loading infusion of 60 mg over 15 minutes and a maintenance infusion of 1.4 mg/min. Therapy was continued for 24 hours in initially responding patients. With analysis of 24-h taped electrocardiograms it was found that single premature ventricular complexes (PVCs) were suppressed by tocainide by more than 80% in 94% of patients and by lidocaine in 75% of patients (p = NS). Couplets and ventricular tachycardia events were eliminated in all patients by either drug. Multiform PVCs were abolished in 94% of the patients after tocainide and in 75% after lidocaine (p = NS). Average overall success over the 24 hours with more than 80% suppression of single PVCs and simultaneous elimination of higher forms of arrhythmia was 71% with tocainide and 59% with lidocaine (p = NS). Adverse effects were negligible, with only one patient in the lidocaine group developing diaphoresis without necessitating termination of therapy. Treatment rapidly produced and then maintained blood levels of 4-10 mg/l for tocainide and 1-4 mg/l for lidocaine. We conclude that intravenous tocainide is well tolerated and has comparable efficacy to lidocaine in the acute therapy of postcardiac surgery ventricular arrhythmias.

Adult↗
PubMed1989

Surgical therapy for drug-refractory ventricular tachycardia: results with mapping-guided subendocardial resection.

Surgical therapy with mapping-guided subendocardial resection was used in 30 patients with drug-refractory ventricular tachycardia. Results of preoperative, intraoperative and postoperative electrophysiologic evaluation and long-term clinical follow-up are reported. Left ventricular aneurysm was located in the inferior wall in 8 patients and in the anterior wall in 22. Left ventricular mapping was performed in 15 patients preoperatively and in all 30 patients intraoperatively. Subendocardial resection was supplemented with cryoablation in 26 patients and with laser photocoagulation in 4. Coronary bypass surgery was performed in 27 patients. The surgical mortality rate was 10%; the three deaths were due to cardiogenic shock, pneumonia and sepsis, respectively. At postoperative electrophysiologic study, ventricular tachycardia was inducible in 8 (30%) of 27 patients. Previously ineffective antiarrhythmic drugs were effective in preventing the induction of ventricular tachycardia in four of these eight patients. Two of the remaining four patients received an automatic implantable cardioverterdefibrillator; the other two were treated with amiodarone. At a mean follow-up period of 18 +/- 17 months (range 1 to 52), there has been one sudden death and one nonfatal recurrence of ventricular tachycardia in the 18 patients without inducible arrhythmias postoperatively. Among the eight patients with inducible ventricular tachycardia after subendocardial resection, there has been one nonfatal ventricular tachycardia recurrence. Thus, among the 27 patients surviving surgery, 17 (63%) were cured with surgery alone, and another 7 (26%) had their ventricular tachycardia controlled with drugs (n = 5) or the defibrillator (n = 2). Inability to completely map the tachycardia, a clinical history of cardiac arrest requiring resuscitation and the presence of myocardial infarction within 2 months predicted postoperative arrhythmia inducibility and recurrence.

Adult↗
PubMed1987

Cor triatriatum associated with partial anomalous pulmonary venous connection to the coronary sinus: echocardiographic and angiocardiographic features.

An infant girl is described who had cor triatriatum and partial anomalous pulmonary venous connection of the left pulmonary veins to the coronary sinus, the first report of this combination of lesions. The infant also had a Dandy-Walker malformation and multiple facial and intrathoracic hemangiomas. The cardiac diagnosis was made by two-dimensional echocardiography. Cardiac catheterization and angiography confirmed the findings and also demonstrated a persistent left superior vena cava draining to the coronary sinus. The infant underwent successful surgical repair. Partial anomalous pulmonary venous connection and left superior vena cava not infrequently are associated with cor triatriatum. Although two-dimensional echocardiography is sensitive for the detection of cor triatriatum, preoperative cardiac catheterization is necessary to identify unequivocally systemic and pulmonary venous connections.

Angiocardiography↗
PubMed1983

Transaxial tomography: an alternative to computerized tomography in pediatric orthopedic problems.

Because of the information it provides, computerized tomography has gained wide acceptance. However, the radiation delivered is considerable, and the gonads cannot be shielded effectively. Transaxial tomography also produces a cross-sectional image. While the image has less resolution, it is obtained at a fraction of the exposure. The use of transaxial tomography in several clinical situations is outlined here.

Bone Diseases↗
PubMed1982

Application of Horton-Devine principles to the repair of hypospadias.

We describe the results and complications of the Horton and Devine techniques for repairing hypospadias in 140 children. The V-shaped glandar flap plasty was done in all patients, either as part of a 1-stage operation in some or as the final step in a staged procedure in others. The principles of Horton and Devine were found useful not only in primary repairs but also in achieving a satisfactory result in secondary and complicated cases. Urethrocutaneous fistula was the most common complication. With an average of 1.5 operations per patient the functional and cosmetic results have been excellent.

Humans↗
PubMed1980

Scoliosis secondary to fractures of the transverse processes of lumbar vertebrae.

Fractures of the transverse processes of the lumbar vertebrae may be difficult to identify radiographically because they are often obscured by gas and feces. With unilateral fractures, there is often scoliosis convex to the side of the fractures. We propose that this may be due to the ineffective action of the ipsilateral quadratus lumborum muscle which inserts into the transverse processes. The unopposed action of the contralateral quadratus lumborum results in scoliosis convex to the side of the fracture(s). Awareness of this cause of scoliosis can help in differentiating it from scoliosis caused by other painful abdominal processes, and may aid in recognition of the fracture(s).

Adolescent↗