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Biomedical subjects

L C Kao

Publications and source records attributed to L C Kao.

44 records · Page 3Linked to original sources
PubMed1985

Decreased specific airway conductance in infant apnea.

A disorder of respiratory control is the suspected etiology in a majority of infants with apnea. Although neurologic control of breathing has been evaluated in infants surviving an apneic episode, pulmonary mechanics have not been previously measured. Pulmonary mechanics were measured during sleep in ten infants with apnea, aged 45.4 +/- 1.4 (SE) weeks postconception, and 13 control infants, aged 42.0 +/- 0.8 weeks postconception. Infant apnea patients were defined as those having at least one episode of cyanosis, limpness, and apnea requiring vigorous stimulation or resuscitation to restore normal breathing, and in whom no treatable etiology could be found. Thoracic gas volume, airway resistance, and specific airway conductance were measured in an infant body pressure plethysmograph during quiet breathing. Dynamic pulmonary compliance was measured in six infants using an esophageal balloon. Specific airway conductance was decreased in infants with apnea compared with control infants (P less than .05). Thoracic gas volume, airway resistance, and dynamic pulmonary compliance values were comparable with those of control infants. These data suggest that airway narrowing or abnormal control of airway tone during sleep may contribute to apnea in some infants.

Airway Resistance↗
PubMed1984

Triglycerides, free fatty acids, free fatty acids/albumin molar ratio, and cholesterol levels in serum of neonates receiving long-term lipid infusions: controlled trial of continuous and intermittent regimens.

We compared intermittent (8 hours/day) versus continuous (24 hours/day) isocaloric lipid infusion regimens in 28 neonates. The lipid dose was increased incrementally by 0.5 gm/kg/day to either 3 gm/kg/day or until fat contributed 40% of daily calories. Serum total triglycerides, free fatty acids, free fatty acids/albumin molar ratio, and total cholesterol levels were measured prior to the daily lipid infusion, at the end of the intermittent infusion, and at 8 hours during the continuous infusion. Neonates less than 32 weeks postconception had significant fluctuation of triglycerides, free fatty acids, and free fatty acids/albumin molar ratio during the intermittent regimen at all lipid doses, but not during the continuous regimen. Neonates greater than or equal to 32 weeks postconception had significant fluctuation of serum triglycerides, free fatty acids, and free fatty acids/albumin molar ratio during the intermittent regimen with a lipid dose greater than or equal to 2 gm/kg/day, but not during the continuous regimen at all lipid doses. Serum free fatty acids correlated closely with serum triglycerides during both regimens (r = 0.89, P less than 0.001). Serum total cholesterol rose with increasing lipid doses during both regimens (f = 8.16, P less than 0.05). We conclude that neonates less than 32 weeks postconception tolerate the continuous regimen better than the intermittent regimen at all lipid doses; neonates greater than or equal to 32 weeks postconception tolerate both regimens well at lipid dose less than 2 gm/kg/day, but tolerate a continuous regimen better with lipid dose greater than or equal to 2 gm/kg/day.

Cholesterol↗
PubMed1984

Effect of oral diuretics on pulmonary mechanics in infants with chronic bronchopulmonary dysplasia: results of a double-blind crossover sequential trial.

In a randomized double-blind crossover trial with sequential analysis, the effects of oral diuretics were compared with the effects of placebo on pulmonary mechanics in ten infants with bronchopulmonary dysplasia (BPD). Pulmonary mechanics were measured before and at the end of a week of treatment with oral diuretics (chlorothiazide, 20 mg/kg/dose and spironolactone, 1.5 mg/kg/dose) given twice daily, or placebo. Mean airway resistance decreased 35.3 cm H2O/L/s, mean specific airway conductance increased 0.095 1/L/s/cm H2O, and mean dynamic pulmonary compliance increased 1.74 mL/cm H2O during treatment with diuretics (all P less than .001), but not during treatment with placebo. The infants' rate of weight gain decreased on the first three days of diuretic treatment, but was thereafter comparable with weight gain during treatment with placebo. Fluid intake was similar in infants receiving diuretics and placebo. But, infants receiving diuretics not only had significantly increased urine output, osmolal clearance, and potassium and phosphorus excretion, but these infants also retained less fluid, and, in addition, excreted less calcium than infants receiving placebo. It is concluded that oral diuretics improve lung function in infants with chronic bronchopulmonary dysplasia; however, potassium and phosphorus depletion are potential complications of treatment.

Administration, Oral↗
PubMed1984

Effect of isoproterenol inhalation on airway resistance in chronic bronchopulmonary dysplasia.

The effects of isoproterenol inhalation on pulmonary mechanics in ten infants with bronchopulmonary dysplasia (BPD), aged 41 +/- 1 (SE) weeks postconception, with gestational age at birth 30 +/- 1 weeks, and birth weight 1,590 +/- 200 g were studied. The infants had: (1) hyaline membrane disease requiring mechanical ventilation in the first five days of life, (2) mechanical ventilation and/or FIo2 greater than 30% for at least 30 days, and (3) stage III or IV radiographic changes. Thoracic gas volume, airway resistance, and specific airway conductance were measured in an infant body pressure plethysmograph during quiet breathing. Dynamic pulmonary compliance was measured using an esophageal balloon. These infants with BPD had greater airway resistance, lower specific airway conductance, and lower dynamic pulmonary compliance than 16 normal control infants (age 40 +/- 1 weeks postconception). In the infants with BPD, measurements were obtained before and 1/2, 1, 2, and 6 hours after the administration of isoproterenol aerosol 0.1% inhalation or saline aerosol placebo, five breaths by slow inflation of the lungs with an anesthesia bag. Within 30 minutes after isoproterenol inhalation, airway resistance decreased 28% +/- 5% and specific airway conductance increased 53% +/- 15%. Thoracic gas volume and dynamic pulmonary compliance did not change. There were no changes following administration of the placebo. Isoproterenol inhalation is associated with rapid short-term improvement in airway resistance and specific airway conductance in infants with BPD.

Aerosols↗
PubMed1983

Furosemide acutely decreases airways resistance in chronic bronchopulmonary dysplasia.

We studied the effects of furosemide on pulmonary mechanics in 10 infants with bronchopulmonary dysplasia aged 41 +/- 1 (SE) weeks post-conception, gestational age at birth 30 +/- 1 wk, birth weight 1370 +/- 200 gm. Thoracic gas volume, airways resistance, and specific airway conductance were measured in an infant body pressure plethysmograph during quiet breathing. Dynamic pulmonary compliance was measured using an esophageal balloon. Infants with BPD had greater Raw, lower SGaw, and lower Cdyn than did 16 normal control infants. Within one hour after administration of furosemide 1 mg/kg IV to infants with BPD, Raw fell 36 +/- 13%, SGaw increased 84 +/- 22%, and Cdyn increased 54 +/- 13%; TGV did not change. Diuretic treatment of BPD in infants is associated with rapid, short-term improvement in Raw and Cdyn.

Airway Resistance↗
PubMed1979

Naloxone antagonism of electrical stimulation induced tail erection in mice.

Tail erection was induced by focal electrical stimulation of the mesencephalic central gray through chronically implanted electrodes in mice. The response was current intensity dependent. Pretreatment with naloxone (5 mg/kg IP), a specific narcotic antagonist, abolished tail erection produced by low electrical current. In contrast, the tail response elicited by higher current was only partially blocked by naloxone. The results suggest that electrical stimulation induces tail erection by releasing an endogenous opioid peptide from the mesencephalic central gray.

Animals↗
PubMedDate not supplied

Effect of total parenteral nutrition with intravenous fat on lipids and high density lipoprotein heterogeneity in neonates.

Plasma lipid concentrations and high density lipoprotein (HDL) subclass distributions were evaluated in 22 newborn infants nourished with intravenous (iv)-fat. The majority of infants were premature with respiratory distress syndrome. Based on baseline (prior to iv-fat) HDL subclass profiles determined by gradient gel electrophoresis (GGE), infants fell into two classes, one with two or more pronounced peaks within the normal HDL spectrum (group I, 17 subjects) and the other with highly unusual HDL distribution (group II, five subjects). Total plasma cholesterol increased in both groups during low and high fat intravenous feeding. HDL-cholesterol, however, did not change with iv-fat where mean values for groups I and II at baseline, iv-low fat and -high fat were: group I, 31.2 +/- 7.1, 30.0 +/- 8.8, and 36.6 +/- 16.7 mg/dl, respectively; and group II, 20.0 +/- 7.8, 20.2 +/- 7.4, and 19.8 +/- 8.8 mg/dl, respectively. Unlike HDL-cholesterol levels that remained constant with iv-fat, apolipoprotein (apo) AI concentrations increased significantly: group I, 73.0 +/- 11.0, 88.3 +/- 15.9, and 93.1 +/- 21.9 mg/dl, respectively; and group II, 31.8 +/- 10.5, 41.0 +/- 12.8, and 59.3 +/- 18.5 mg/dl, respectively. In group I infants, iv-fat is associated with an increase in larger-sized particles, particularly in the (HDL2b)gge range; in group II there is an increase in (HDL3b)gge and (HDL3c)gge components and a disappearance of particles that fall outside of the size range of normal HDL. In both groups, enteral feeding is associated with a further normalization of HDL subclass distribution. The aberrant GGE profiles and very low apoAI levels of group II infants at baseline were associated with unusual HDL morphology determined by electron microscopy where discoidal structures were prominent. With iv-fat, discoidal particles decline in number while normal spherical structures increase. Prevalence of discoidal HDL at baseline was associated with low concentrations of lecithin:cholesterol acyltransferase (LCAT) (1.12 +/- 0.5 micrograms/ml); with iv-fat this enzyme rose to 1.61 +/- 0.18 micrograms/ml. Increased LCAT is associated with the normalization of HDL morphology. It is likely that iv-fat improves the nutritional status of premature infants, thereby stimulating increased liver synthesis of important proteins, including apoAI and LCAT, associated with HDL metabolism.

Apolipoprotein A-I↗