Immunosuppressive drugs and HHV-8 in a patient with a renal transplant and Kaposi's sarcoma.
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Cyclosporine↗
Biomedical subjects
Y J Lin
Publications and source records attributed to Y J Lin.
Efficacy of nasal intermittent positive pressure ventilation in treating apnea of prematurity.
The efficacy of nasal intermittent positive pressure ventilation (NIPPV) in treating apnea of prematurity was evaluated. Apneic preterm infants were randomly assigned to receive either NIPPV or continuous positive airway pressure (NCPAP) for 4 hr when they failed to respond to conservative therapy. The amount of reduction in apneic spells and bradycardia in the two groups after treatment was compared. Thirty-four infants (18 with NIPPV, 16 with NCPAP) were enrolled. Their birth weights ranged from 590-1,880 g (mean, 1,021 g) and gestational ages from 25-32 weeks (mean, 27.6 weeks). The baseline characteristics were comparable in the two groups. Frequency of apnea and bradycardia was reduced during both forms of treatments. However, the infants receiving NIPPV had a greater reduction of apneic spells (P = 0.02) and a tendency to greater decrease in bradycardia (P = 0.09) than those receiving NCPAP. We conclude that NIPPV is more effective than NCPAP in reducing apnea in preterm infants. NIPPV may reduce bradycardia; however, this needs to be validated by a larger number of observations.
Apnea↗
Role of transesophageal echocardiography in the evaluation of patients with clinical pacemaker syndrome.
OBJECTIVES: The goal of this study was to investigate the possible role of transesophageal echocardiography in the evaluation of patients with clinical pacemaker syndrome. BACKGROUND: Several reports on transthoracic echocardiographic features of ventricular pacing were described; however, no previous study of transesophageal echocardiography has been undertaken in patients at the severe end of pacemaker syndrome who need reprogramming of dual-chamber pacing for symptom relief. METHODS: Twelve patients with ventricular-inhibited pacemakers (VVI) with clinical symptomatic pacemaker syndrome (group I) and 10 patients with VVI without pacemaker syndrome (group II) were prospectively studied. The two groups were pacemaker dependent and had persistent ventriculoatrial conduction. Transesophageal echocardiographic parameters were assessed in group II and within 6 hours before reprogramming to the DDD mode in group I. Follow-up transesophageal echocardiographic study was performed 28+/-5 days after reprogramming in group I. RESULTS: All patients in group I had subjective improvements of symptoms after DDD reprogramming. The atrial reverse flow velocities of pulmonary veins in group I before reprogramming were significantly higher in group II (39.3+/-11.4 versus 15.7+/-13.5 cm/sec, p < 0.0001). Spontaneous echo contrast in the descending aorta was detected in all patients from group I before reprogramming. The prevalence of significant mitral regurgitation (> or = moderate) was significantly higher in group I before reprogramming than in group II (67% versus 8%, p = 0.01). Significant mitral regurgitation and spontaneous echo contrast in the descending aorta in group I disappeared after reprogramming to the DDD mode. CONCLUSIONS: Transesophageal echocardiography provides physiologic, pacemaker-related hemodynamic changes in paced patients. Significantly higher atrial reverse flow velocities of pulmonary veins, increased frequency of spontaneous echo contrast in the descending aorta, and significant mitral regurgitation are peculiar echocardiographic findings in patients with VVI with clinical pacemaker syndrome.
Adult↗
Airway closure during mixed apneas in preterm infants: is respiratory effort necessary?
Airway closure during mixed apneas in preterm infants may be due to lack of tone in the upper airway followed by collapse and obstruction or diaphragmatic action inducing obstruction. We examine whether respiratory efforts are necessary for airway closure using a new method of detecting airway obstruction, based on the disappearance of an amplified cardiac pulse observed on the respiratory flow tracing. We analyzed 198 episodes of mixed apnea of various lengths (> or = 3 seconds) observed in 33 preterm infants (birth weight, 1.4 +/- 0.1 kg [mean +/- SEM]; study weight, 1.7 +/- 0.1 kg; gestational age, 29 +/- 1 weeks; post-natal age, 33 +/- 4 days). The great majority of these episodes (88%) had a central, followed by an obstructive, component. Infants were studied by using a nosepiece and a flow-through system. Respiratory efforts (abdominal and chest movements) were recorded. Of the apneas, 20 were < 5 seconds; 78, 5 to < 10 seconds; 45, 10 to < 15 seconds; 27, 15 to < 20 seconds; and 28, > or = 20 seconds. Of the 198 mixed apneas, 151 (76%) occurred in the absence of any respiratory effort; 43 (22%) showed a simultaneous cessation of the cardiac oscillation and respiratory effort; and 4 (2%) showed diaphragmatic activity appearing after cessation of the cardiac oscillation (airway occlusion). Respiratory efforts never preceded the cessation of the cardiac oscillation. The findings suggest that diaphragmatic action is not needed to occlude the airway in mixed apneas. The simultaneous cessation of cardiac oscillations (airway occlusion) and onset of respiratory efforts may indicate that such effort contributes to closure or is induced by the same stimulus that closes the airway. We speculate that the mechanism for airway closure in mixed apneas is most likely a lack of upper airway tone, which normally occurs with the cessation of a central drive to breathe.
Airway Obstruction↗
Effects of early postnatal dexamethasone therapy on calcium homeostasis and bone growth in preterm infants with respiratory distress syndrome.
The effects of dexamethasone therapy on calcium homeostasis and bone growth were evaluated in 49 infants (24 placebo and 25 dexamethasone) who participated in a double-blind trial of early dexamethasone therapy for the prevention of chronic lung disease. Dexamethasone (0.25 mg kg(-1) b.i.d. on d 1-7; 0.12 mg kg(-1) b.i.d. on d 8-14; 0.05 mg kg(-1) b.i.d. on d 15-21; 0.02 mg kg(-1) b.i.d. on d 22-28) or saline placebo was given i.v. Serum calcium (Ca), phosphorus (P) and parathyroid hormone (PTH), and the corresponding urinary excretion of calcium (FECa) and phosphorus (FEP) were measured on d 2, 3, 7, 10, 14, 21 and 28 after starting the study. Radiographic evaluations of bone growth were also evaluated. Infants in the dexamethasone group had significantly higher PTH on d 2 (p < 0.01), 7 and 14 (p < 0.05) than infants in the placebo group. The dexamethasone-treated infants also had significantly higher FEP on d 2, 7 and 14 (p < 0.05) and lower FECa on d 7 and 14 (p < 0.05) than control infants. There was no significant difference between the groups in bone growth during the study. It was concluded that early dexamethasone therapy causes a transient elevation in PTH without apparent change in bone growth. The long-term effect remains to be evaluated further.
Age Factors↗
Acute pseudorejection--intermittent dextrorotation of the uterus causing graft compression.
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Adult↗
Long-term outcome of radiofrequency catheter ablation for typical atrial flutter: risk prediction of recurrent arrhythmias.
INTRODUCTION: Little is known about the predictors of recurrent atrial flutter or fibrillation after successful radiofrequency ablation of typical atrial flutter. In addition, there is only limited evidence suggesting that elimination of atrial flutter would modify the natural history of atrial fibrillation in patients who experienced both of these arrhythmias. The aims of the present study were to investigate the long-term results of radiofrequency catheter ablation and to examine the predictors for late occurrence of atrial fibrillation in a large population with typical atrial flutter. METHODS AND RESULTS: The study population consisted of 144 patients (mean age 56 +/- 18 years) with successful ablation of clinically documented typical atrial flutter. In the first 50 patients, successful ablation was defined as termination and noninducibility of atrial flutter; for the subsequent 94 patients, successful ablation was defined as achievement of bidirectional isthmus conduction block and no induction of atrial flutter. The clinical and echocardiographic variables were analyzed in relation to the late occurrence of atrial flutter or fibrillation. Over the follow-up period of 17 +/- 13 months, 14 (9.7%) patients had recurrence of typical atrial flutter. In the first 50 patients, 8 (16%) had recurrence of atrial flutter, compared with only 6 (6%) of the following 94 patients. Patients with incomplete isthmus block had a significantly higher incidence of recurrent atrial flutter than those with complete isthmus block (6/16 vs 0/78, P < 0.0001) in the following 94 patients. There was no predictor for recurrence of atrial flutter after successful ablation as determined by univariate and multivariate analysis. Although successful ablation of atrial flutter eliminated atrial fibrillation in 45% of patients with a prior history of atrial fibrillation, 31 (21.5%) of 144 patients undergoing this procedure developed atrial fibrillation during the follow-up period. Univariate analysis revealed that three clinical variables were related to the occurrence of atrial fibrillation: (1) the presence of structural heart disease; (2) a history of atrial fibrillation before ablation; and (3) inducible sustained atrial fibrillation after ablation. By multivariate analysis, only a history of atrial fibrillation and inducible sustained atrial fibrillation could predict the late development of atrial fibrillation after atrial flutter ablation. CONCLUSION: Radiofrequency catheter ablation of typical atrial flutter is highly effective and associated with a low recurrence rate of atrial flutter, but atrial fibrillation continues to be a long-term risk for patients undergoing this procedure. The presence of structural heart disease and prior spontaneous or inducible sustained atrial fibrillation increases the risk of developing atrial fibrillation.
Aged↗
PKC activation is required by EGF-stimulated Na(+)-H+ exchanger in human pleural mesothelial cells.
Epidermal growth factor (EGF) stimulates the Na(+)-H+ exchanger, leading to enhanced cell proliferation. In human pleural mesothelial cells (PMCs), the intracellular signaling mechanism mediating the EGF-induced stimulation of the Na(+)-H+ exchanger has not yet been identified. Using a pH-sensitive fluorescent probe, 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, to measure changes in intracellular pH (pHi), we found that 1) EGF and 12-O-tetradecanoylphorbol 13-acetate (TPA; a phorbol ester) both stimulate the ethylisopropyl amiloride-sensitive Na(+)-H+ exchanger; 2) TPA-induced alkalosis can be blocked by protein kinase C (PKC) inhibitors (chelerythrine and staurosporine) or by PKC down-regulation, indicating that PKC activation is involved in the stimulation of the Na(+)-H+ exchanger. However, TPA-induced alkalosis is not blocked by tyrosine kinase inhibitors; and 3) the stimulatory effect of EGF on the Na(+)-H+ exchanger acts via stimulation of tyrosine kinase-receptor activity because it is inhibited by tyrosine kinase inhibitors (genistein, lavendustin A, and herbimycin A). It also involves PKC activation because EGF-induced alkalosis was blocked by PKC inhibitors. These results suggest that PKC activation is one of the downstream signals for EGF-induced activation of the Na(+)-H+ exchanger in primary cultures of human pleural mesothelial cells.
Cells, Cultured↗
Cardiac output and mixed venous O2 content measurements by a tracer bolus method: animal validation study.
A bolus method for noninvasive measurement of cardiac output (CO) and mixed venous oxygen content (O2) has been tested against absolute CO and O2 standards in dogs. No statistical differences in CO were found between bolus method and electromagnetic flowmeter measurement comparisons in an 18-dog study in which CO varied from 0. 5 to 3.0 l/min. The SD for all paired differences was 0.14 l/min; however, data averaging over 10-min intervals were found to reduce the CO measurement uncertainty to <0.08 l/min. The ability of the bolus method to follow rapid CO changes, experimentally produced by control of a pump (surgically placed between the superior and inferior vena cava and the right atrium), was documented and found to satisfy CO monitoring requirements of unstable subjects. O2 bolus values were found to be statistically equivalent to reference measurements.
Animals↗
Early dexamethasone therapy in preterm infants: a follow-up study.
OBJECTIVES: To study the outcome at 2-year corrected age of infants who participated in a double-blind controlled trial of early (<12 hours) dexamethasone therapy for the prevention of chronic lung disease (CLD). METHODS AND MATERIALS: A total of 133 children (70 in the control group, 63 in the dexamethasone-treated group) who survived the initial study period and lived to 2 years of age were studied. All infants had birth weights of 500 to 1999 g and had severe respiratory distress syndrome requiring mechanical ventilation within 6 hours after birth. For infants in the treatment group, dexamethasone was started at a mean age of 8.1 hours and given 0.25 mg/kg every 12 hours for 1 week and then tapered off gradually over a 3-week period. The following variables were evaluated: interim medical history, socioeconomic background, physical growth, neurologic examinations, mental and psychomotor development index score (MDI and PDI), pulmonary function, electroencephalogram, and auditory and visual evoked potential. RESULTS: Infants in the control group tended to have a higher incidence of upper respiratory infection and rehospitalization than did the dexamethasone-treated group because of respiratory problems. Although there was no difference between the groups in somatic growth in girls, the dexamethasone-treated boys had significantly lower body weight and shorter height than the control boys (10.7 +/- 3.0 vs 11.9 +/- 2.0 kg; 84.9 +/- 5.7 vs 87.5 +/- 4.8 cm). The dexamethasone-treated group had a significantly higher incidence of neuromotor dysfunction (25/63 vs 12/70) than did the control group. The dexamethasone-treated infants also had a lower PDI score (79 +/- 26) than did the control group (87 +/- 23), but the difference was not statistically significant. Both groups were comparable in MDI, incidence of vision impairment, and auditory and visual evoked potential. Significant handicap, defined as severe neurologic defect and/or intellectual defect (MDI and/or PDI </= 69), was seen in 22 children (31.4%) in the control group and 26 (41.2%) in the dexamethasone-treated group. CONCLUSIONS: Although early postnatal dexamethasone therapy for 4 weeks significantly reduces the incidence of CLD, this therapeutic regimen cannot be recommended at present because of its adverse effects on neuromotor function and somatic growth in male infants, detected at 2 years of age. A longer follow-up is needed. If early dexamethasone therapy is to be used for the prevention of CLD, the therapeutic regimen should be modified. The proper route of administration, the critical time to initiate the therapy, and the dosage and duration of therapy remain to be defined further.
Child Development↗
Relation of systemic arterial pulse pressure to coronary atherosclerosis in patients with mitral stenosis.
The relation of a wide systemic arterial pulse pressure to coronary atherosclerosis has not been fully defined. One hundred fifty-nine patients > 40 years old with symptomatic mitral stenosis (MS) who received routine coronary angiography were classified into 2 groups according to the presence of > or = 50% diameter narrowing of > or = 1 coronary artery (n = 48) or no significant disease (n = 111). Pulse pressure was determined both by noninvasive sphygmomanometer and invasive catheterization methods. There were no significant differences in risk factors of coronary artery disease (CAD) or the severity of MS between the 2 groups. From multivariate logistic regression analysis, independent predictors of development of CAD in MS were age (standardized coefficient beta = 1.3437, p = 0.0025), gender (beta = 0.0107, p = 0.0105), mean blood pressure (beta = 1.1839, p = 0.0105), and pulse pressure (beta = 1.3157, p = 0.0008). A wide pulse pressure (> or = 60 mm Hg) correlated with the presence of angiographically significant CAD with a sensitivity and specificity of 88% and 77%. The negative predictive value was 93%. Pulse pressure assessed by sphygmomanometry provided important clinical information. A wide pulse pressure in patients with MS was associated with a high incidence of CAD.
Adult↗
Painless Prinzmetal's ST elevation related to propranolol: a case report.
Previous studies have shown that propranolol, an effective mainstay for angina pectoris and unstable angina, can induce coronary arterial spasm in patients with variant angina. However, no report has yet associated it with painless Prinzmetal's ST elevation in patients without a history of variant angina. The present communication describes such an unusual and negligible case after propranolol overdose. Coronary arterial spasm can be induced by beta-blocker, not only in patients with variant angina but also in normal persons.
Administration, Oral↗
Early postnatal dexamethasone therapy may lessen lung inflammation in premature infants with respiratory distress syndrome on mechanical ventilation.
Early postnatal use of dexamethasone has recently been shown to be effective in improving the pulmonary status in premature infants with respiratory distress syndrome (RDS). To study the effect of dexamethasone on pulmonary inflammatory responses, we studied ten infants treated with dexamethasone and ten infants without this treatment. Serial tracheal aspirates were obtained for cell counts, neutrophil counts, total protein concentrations, and leukotriene B4 (LTB4) and 6-keto prostaglandin (PG)F(1 alpha) levels before and after starting the study. Infants in the dexamethasone-treated group required significantly lower mean airway pressures for ventilation and had lower PaCO2 values from day 3 to day 14 than infants in the control group, suggesting better pulmonary function. For infants in the dexamethasone group, the tracheal aspirates showed significantly lower cell and neutrophil counts, protein concentrations, and 6-keto-PGF(1 alpha) and LTB4 levels than in the control group. We conclude that early postnatal dexamethasone therapy may lessen lung inflammation and improve pulmonary function in infants with RDS.
6-Ketoprostaglandin F1 alpha↗
Manganese ion enhances T1-weighted MRI during brain activation: an approach to direct imaging of brain function.
Present techniques for functional MRI rely on detecting changes in hemodynamics that result as a consequence of brain activation. It would be useful if MRI techniques could be developed that enable imaging of a parameter directly related to neuronal activity. Influx of calcium into neurons is necessary for release of neurotransmitters. Divalent manganese ions (Mn2+) can enter cells through voltage-gated calcium channels and Mn2+ is paramagnetic. Mn2+ accumulation in brain due to activation should alter relaxation times offering an approach to sensitize MRI to calcium influx in the brain. To test this idea, T1-weighted MRI was obtained from the rat brain in the presence of a continuous intravenous infusion of 3.6 mumol/min MnCl2. In the anesthetized rat brain, signal enhancement was detected in regions corresponding to ventricles. Activation of the brain with glutamate led to increase in MRI signal intensity in the brain to 238 +/- 23% of the original. This increase in signal was dependent on the presence of MnCl2 and was not due to changes in blood flow. It was necessary to break the blood brain barrier with mannitol to make Mn2+ accessible to the active sites for efficient detection. Enhancement of MRI signal in the brain was also detected with decreasing anesthesia and with somatosensory stimulation. Due to the slow clearance of Mn2+ from the stimulated region of the brain, MRI enhancement could also be detected after stimulation that occurred on awake, behaving rats outside the magnet. These data indicate that MnCl2 shows potential as a MRI contrast agent that is directly sensitive to brain activation.
Animals↗
Qualitative and quantitative analysis of diazinon in fabric exposed to various simulated sunlight and humidity conditions.
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Chromatography, Gas↗
Congenital bilateral agenesis of diaphragm: report of a case.
UNLABELLED: Bilateral agenesis of the diaphragm is a rare, life-threatening malformation. Infants with this defect rarely survive to have surgical intervention. We report a 32-week premature female infant who was born to a 36-year-old mother via vaginal delivery. The pregnancy course was complicated by hypertension and polyhydramnios. Cytogenetic study showed a normal 46 XX female karyotype. She had cyanosis, respiratory distress and scaphoid abdomen at birth. A roentgenograph confirmed the diagnosis of diaphragmatic hernia. Surgery was performed at 21 h of age. Bilateral agenesis of diaphragm, herniation of abdominal organs and oesophagus and pulmonary hypoplasia were noted. Furthermore, stomach and spleen were adherent to the mediastinum and vertebrae. The patient developed hypotension and persistent hypoxaemia and expired at age of 26 h. Autopsy revealed bilateral agenesis of diaphragm, hypoplasia of lungs, and pancreas fibrosis with mild hypoplasia of islets of Langerhans. CONCLUSION: Bilateral agenesis of diaphragm associated with pancreas fibrosis is a rare entity, and its clinical significance needs further investigation.
Abnormalities, Multiple↗
The best operation for rectal prolapse.
Rectal prolapse remains a disorder for which the cause is not clearly understood and the best method of management is debated. Because the natural history of prolapse frequently leads to complications of incontinence and constipation, we believe that all patients presenting with internal and external prolapse should be considered for repair. Although the type of operative repair recommended may vary, it is clear that all patients with external rectal prolapse should be offered some type of repair. What is not clear from the literature is the appropriate management of those patients with internal prolapse. As shown in the George Washington University experience, surgery is rarely performed for isolated internal prolapse. Most patients who present with internal prolapse also have an associated enterocele, rectocele, or cystocele. Repair of the internal prolapse and the associated disorder may benefit many of these patients. If internal prolapse is an isolated finding, it is not clear to what extent the prolapse is responsible for the patient's symptoms, and repair is generally not advised. These guidelines are easy to enumerate but may be difficult to practice in some patients. Therefore, ongoing evaluation of clinical results is critical to improve our understanding of these disorders. This discussion has outlined the current theories of the cause of rectal prolapse, the symptoms and findings patients present with, and the possible approaches to repair.
Colorectal Surgery↗
Identification of a promoter for the latent membrane protein 1 gene of Epstein-Barr virus that is specifically activated in human epithelial cells.
Latent membrane protein 1 (LMP 1) is one of two Epstein-Barr virus (EBV)-encoded proteins that expressed in nasopharyngeal carcinoma (NPC) cells. Previous studies showed that a 3.5-kb transcript of the LMP 1 gene, in addition to the 2.8-kb transcript, was detected in a B95-8-EBV-containing, nude mice-passaged NPC tumor, C15. This indicated that a transcript was initiated from a region 5' to the putative promoter, ED-L1. We have isolated an EBV variant from a NPC tissue, and this virus strain contained a more pathogenic LMP 1 gene. DNA sequence analysis of the 5'-upstream region showed distinct variations as compared to that of B95-8 strain. To test if the LMP 1 gene of the NPC strain also contained an upstream promoter, we generated a series of deletion plasmids encompassing positions -1,030 to +20 of the LMP 1 promoter and tested for their abilities to drive the expression of the reporter gene in human epithelial cell lines, C-33A and NPC-TW076. We found that the region between -643 and -496 contained a promoter activity that was approximately five-fold higher than the putative promoter, ED-L1. This region between -643 and -496 was designated as ED-L1E. C-33A cells containing the genomic clone pT7(E) or the clone that had deleted a 94-bp ED-L1 sequence (delta94) was used to determine the transcription initiation sites by RNase protection assay. Results showed that a transcription initiation site was located at nucleotide 170,099 ("A") of EBV genome. The transcript was expressed in NPC biopsies and in human primary normal epithelial cells transfected with pT7(E) and delta94, respectively, as examined by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Furthermore, the ED-L1E was not regulated by the EBV-encoded nuclear antigen 1-mediated transcriptional enhancer family of repeats (FR) in C-33A cells. Our results suggested that the ED-L1E was specifically activated in epithelial cells. The biological significance of the selective usage of the ED-L1E promoter was discussed.
B-Lymphocytes↗