摘要:

SummaryThe volume overloading of the left ventricle which results from left to right (L-R) shunting through a ventricular septal defect (VSD) may be reduced by pharmacologic agents which lower systemic vascular resistance (Rs) in excess of pulmonary arteriolar vascular resistance (Rpa). To study agents capable of decreasing the L-R shunt through systemic vasodilatation, we created a chronic lamb model with VSD and administered three vasodilators, prazosin (0.05 mg/kg), hydralazine (0.75 mg/kg), and minoxidil (0.25 mg/kg). Prazosin increased the Rpawhile lowering Rs, resulting in an increase in Rpa/Rsby 43% {p≤ 0.005). Prazosin decreased the pulmonary flow (&OV0422;p) slightly, decreased L-R shunt by 16%, reduced the pulmonary to systemic flow ratio (&OV0422;p/&OV0422;s) by 22% (p≤ 0.005), and lowered the left atrial mean pressure (&OV0436;A) by 16% (p≤ 0.005) with no effect on heart rate. Hydralazine lowered the Rpaand Rsequally and thus did not change the Rpa/Rsor the volume of L-R shunt (7.6 versus 8.1 Iiters/min/m2). No change in &OV0436;A was seen with hydralazine but heart rate increased from 162 to 200/min (p≤ 0.01). Minoxidil did not change the L-R shunt (6.9versus6.8 liters/min/m2) and, in general, produced effects intermediate between prazosin and hydralazine. The data support a selective systemic vasodilation with prazosin, a property not shared by either minoxidil or hydralazine, which results in a reduction of shunting and left ventricular volume overloading in lambs with VSD. Furthermore, since prazosin did not decrease the pulmonary resistance, the data indicate that the elevation in pulmonary resistance in lambs with VSD is not mediated by the α1-adrenergic receptor.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

SummaryThree patients with Menkes' disease, an inherited disorder of copper transport, were studied to determine whether the copper deficiency was associated with a lipoprotein disorder. Hypocuprinemia was documented in all three cases. Two patients had severe copper and ceruloplasmin deficiencies, whereas the third patient had a less severe deficiency. Hypertriglyceridemia was observed in the first patient, and elevations in triglyceride, cholesterol, apolipoprotein B (ApoB), and apolipoprotein C-III (ApoC-III) occurred predominantly in the very low density lipoprotein fraction (VLDL). This patient had normal lipoprotein lipase activity but mild glucose intolerance. The second patient had a borderline high cholesterol level with normal plasma triglycerides and apolipoproteins, whereas the third patient appeared to have normal total cholesterol but slightly higher triglycerides with elevated plasma apolipoprotein E (ApoE). No striking differences were observed in the chemical composition of all lipoprotein subfractions between patients and controls except that the neutral lipid content of VLDL was higher in patients than in controls. The ApoB was initially normal in molecular weight but degraded faster than the controls during storage. The appearance of the major low density lipoprotein (LDL) fraction of the first two patients was opaque white, in contrast to clear yellow in the third patient and in the age- and diet-matched controls. This abnormal appearance of LDL in these patients was associated with low plasma levels ofβ-carotene and ceruloplasmin. These findings suggest that decreased serum copper levels may be associated with lipid and lipoprotein abnormalities and may enhance lipid peroxidation of LDL accounting for the color change. The increase in neutral lipids and the damaging effects on lipoprotein-transported substances may lead to atherosclerosis.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

SummaryIt was observed that the lung catalase activity of premature (day 21 of gestation; term=22 days) rat pups is affected by maternal iron intake. Pups from control dams receiving Purina Lab Chow and water adlibitumhave only 50% of the lung catalase activity of pups from dams who received 1 mg/kg parenteral iron dextran daily from day 7 to day 20 of gestation. Other oxygen-protective enzymes, copper-zinc and manganese superoxide dismutase, glutathione peroxidase, and glucose-6-phosphate dehydrogenase, were unaffected by maternal iron supplements.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

SummarySeventeen piglets were infected with a continuous intravenous infusion of live group Bβ-hemolytic streptococci (GBS). Hemodynamic changes were recorded, and blood samples were drawn for measurement of thromboxane B2(TxB2) (stable metabolite of thromboxane A2) and 6-keto-PGF1α(stable metabolite of prostacyclin). Control animals (n=9) received only bacteria, while treatment animals (n=8) received indomethacin, 3 mg/kg IV, 15 min after the start of the bacterial infusion. Control animals responded to the bacteria within 15 min with marked elevation in mean pulmonary artery pressure (Ppa) from 15 ± 8 to 39 ± 6 mm Hg and decline in Pao2from 80 ± 11 to 51 ± 6 mm Hg and cardiac output (CO) from 0.24 ± 0.07 to 0.13 ± 0.07 liters/min/ kg. Mean arterial blood pressure (AoP) significantly decreased from baseline value of 95 ± 13 to 51 ± 32 mm Hg by 180 min. In animals treated with indomethacin, these changes were reversed or significantly attenuated. The hemodynamic changes were associated temporally with elevations in plasma concentrations of TxB2or 6-keto-PGF1α. In he first 60 min, TxB2levels in both groups correlated with Ppa (r=0.72,p<0.001) and Pao2(r=-0.60,p<0.001). A strong negative correlation between TxB2and CO was observed over the first 180 min (r=-0.73,p<0.001). There was a statistically significant correlation between AoP and 6-keto-PGF1αconcentration between 60 and 180 min (r=-0.54,p<0.002). Indomethacin improved the hemodynamic function in this model of GBS sepsis. This improvement was related in part to inhibition of synthesis of thromboxane A2and prostacyclin.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

SummaryThe effect of ingestion of uncooked cornstarch (2 g/kg body weight) in water, uncooked starch (1 g/kg) added to a meal, and glucose (2 g/kg) in water, was studied in eight patients with type IAglycogen storage disease (GSD) and one patient with type IBGSD. Blood glucose concentrations were determined at 30-min intervals during each tolerance test; blood lactate, blood insulin, and expiratory hydrogen were determined at 60-min intervals. The glucose levels remained in the normal range (> 1.8 mM) during approximately 6.5-9.0 h, 3.5-6.5 h, and 2.25-4.0 h during the three tolerance tests, respectively. The lactate levels differed markedly for the different tests per patient, and for the same type of test between the patients. Blood insulin concentrations after starch administration did not exceed values of 50 mU/liter above fasting levels and were markedly lower than those after glucose administration (maximum levels of 280 mU/liter). The expiratory hydrogen excretion did not increase or only slightly increased after cornstarch administration (<20 ppm).

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

SummaryThis study was designed to investigate the greatly reduced activities of hepatic lipase and lipoprotein lipase in postheparin plasma of patients with glycogen storage disease (GSD). Evidence for the presence of a circulating inhibitor in the plasma of GSD patients prior to the establishment of metabolic control was provided by the following observations.The hepatic lipase activity from patients with GSD gave a nonlinear relationship with time, maximum activity being obtained after 5 min whereas normal postheparin plasma showed a linear relationship for at least 20 min. The addition of GSD plasma to a normal postheparin plasma resulted in inhibition of the normal postheparin lipolytic activity. The inhibition showed a dose response, with 10 and 30 µl of the GSD plasma giving 22 and 65% inhibition after 20 min, respectively. Serial dilution of GSD postheparin plasma gave increasing activity of hepatic lipase when expressed per ml of plasma. Thus, a 1:100 dilution gave a normal activity of 15 µmol/ml/h whereas a 1:10 dilution gave less than 10% of this activity. After affinity chromatography of the GSD postheparin plasma on heparin/Sepharose, the inhibition was removed and a normal lipolytic activity was obtained.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Vitamin D metabolite levels were measured in 174 normal children throughout the year. 25-hydroxyvitamin D3(25(OH)D3) and 24,25-dihydroxyvitamin D3(24,25(OH)2D3) levels showed a seasonal variation; both levels were higher in summer than in winter (p<0.001 for both). There was a fall in the 1,25-dihydroxyvitamin D (1,25(OH)2D) level in August and September (p<0.001), which coincided with a rise in mean 25(OH)D3and 24,25(OH)2D3levels. An inverse correlation was seen between 1,25(OH)2D and 24,25(OH)2D3levels (r=-0.233;p<0.01). 25(OH)D3levels increased with age only for winter values (<3 years, 11.70 ± 3.98 ng/ml; 3-11 years, 18.38 ± 1.65 ng/ml; >11 years, 23.60 ± 4.60 ng/ml) while 1,25(OH)2D and 24,25(OH)2D3levels did not show an age-related difference. Intake of multivitamins had an interesting effect on 25(OH)D3and 24,25(OH)2D3levels in the winter but not in the summer; the endogenous metabolite levels were lower in the vitamin supplemented children [25(OH)D3: 23.05 ± 7.35versus15.77 ± 5.51 ng/ml,p<0.001; 24,25(OH)2D3: 2.30 ± 1.11versus1.66 ± 0.88 ng/ml,p< 0.05]. Children studied in the winter who were not receiving supplemental vitamins were older than those who did receive the vitamins (7.26 ± 2.64versus5.42 ± 3.17 years;p<0.01). Sixteen of the children had both winter and summer measurements. Their 25(OH)D3and 24,25(OH)2D3levels showed the same seasonal variation as the overall group data, while their 1,25(OH)2D levels showed no consistent pattern. Our data suggest that establishing normal pediatric values for 25(OH)D3, 1,25OH)2D, and 24,25(OH)2D3requires consideration of season, age, and supplemental vitamin D intake, and that such information be available to investigators in order to make meaningful interpretations of vitamin D metabolite levels in disease states.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

SummaryThe activity of Ca-ATPase (Ca2+,Mg2+-ATPase, ATP phosphohydrolase, EC 3.6.1.3) was measured in erythrocyte membrane preparations from 37 cystic fibrosis patients, 27 with pancreatic insufficiency and 10 with pancreatic sufficiency, from 24 healthy controls. The mean maximal calcium-stimulated specific activities, in the absence and presence of purified calmodulin, of the pancreatic sufficient patients (34.3 ± 4.2 and 75.9 ± 6.9 nmol/min/mg) was indistinguishable from that of controls (35.8 ± 2.6 and 84.3 ± 4.7 nmol/min/mg), while both activities of patients with pancreatic insufficiency were significantly decreased (28.9 ± 1.3,p<0.02; 65.2 ± 3.0,p<0.001) compared to the control group. Similarly, the mean erythrocyte membrane (Na + K)ATPase activity was decreased only for those patients with a history of steatorrhea and who clinically required pancreatic enzyme therapy and had low immunoreactive trypsin levels (10.6 ± 0.8versuscontrol, 13.4 ± 1.1, and pancreatic sufficient patients, 13.3 ±1.4 nmol/min/mg;p<0.025). No correlation was found between any of the ATPase activities and the clinical scores of the patients, suggesting the lack of significant contribution of general clinical status to the activities of those cation transporters.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

SummaryWe measured cardiac output and its distribution (microspheres), blood gases and pH, heart rate, and pulmonary and aortic pressures in three groups of 1- to 3-day-old lambs.Group I consisted of six animals who had these measurements made during both control (normoxemic) and hypoxemic (PaO225 ± 3 mm Hg) periods. Hypoxemia increased the pulmonary artery pressure 70% (p<0.01). This elevation in pulmonary arterial pressure lasted as long as the animals were hypoxemic (90 min). Hypoxemia had no effect on cardiac output, mean systemic arterial pressure, heart rate, or the rate-pressure product of the left ventricle. Blood flow to the heart increased an average of 228% (p<0.05); flow to the brain increased 233% (p<0.05); flow to the skin decreased 35% (p<0.05) after 60 and 90 min of hypoxemia. Blood flow to the remaining organs was uneffected by hypoxemia.Group II consisted of four animals who were given 1, 5, and 10 mg/kg/h of tolazoline (Priscoline) intravenously while normoxemic. There was no effect on the pulmonary arterial pressures or blood gases and pH. Tolazoline (5 and 10 mg/kg/h) reduced systemic arterial pressures an average of 22% (p<0.05). Tolazoline (1 mg/kg/h) reduced blood flow to the spleen 48% and that to the brain by 20% and increased flow to the body 32% (p<0.05). Five mg/kg/h of tolazoline decreased renal and brain blood flow 35 and 20%, respectively (p<0.05) while that to the body and liver increased 26 and 48% (p<0.05). Tolazoline (10 mg/kg/h) returned splenic, body, and brain flow to control levels, and decreased renal blood flow further (48%) (p<0.05). Tolazoline had no effect on the left ventricular rate-pressureproduct.Group III was given 1, 5, and 10 mg/kg/h of drug while the animals were hypoxemic (PaO229 ± 4 mm Hg). The mean systemic arterial blood pressures decreased 20% with 5 and 10 mg/kg/h of tolazoline (p<0.05), but tolazoline did not change mean pulmonary arterial pressure. Tolazoline had no effect on the left ventricular rate-pressure products. Cardiac output increased 47% with hypoxemia, but it was unaltered by the addition of tolazoline. Blood flow to the heart increased 300% and that to the brain 200% with hypoxemia and remained at these levels with infusing tolazoline. Flow to the remaining tissues was constant. Five mg/kg/h of tolazoline increased cardiac flow further (560% of control). Ten mg/kg/h maintained the high cardiac flow seen with 5 mg/kg/h infusions of tolazoline, decreased that to the kidneys 33%, and increased flow to the lower body 67%. These data indicate that tolazoline does not decrease the pulmonary hypertension caused by hypoxemia and that tolazoline does little to alter the effect of hypoxemia on the distribution of blood flow.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

SummaryMature human milk samples from young healthy women on an equilibrated diet contained a mean of 81 ng/ml total iodine. Iodide represented a mean of 77% of the total iodine. Of the 22 ng/ml organic iodine, there was about 1 ng thyroxine and triiodothyronine and, after pepsin hydrolysis, up to 40% of organic iodine in monoiodotyrosine form. By electrophoresis, after incubation with radioactive thyroid hormone, we found an absence of binding on thyroxine-binding globulin, but thyroxine and triiodothyronine were bound to albumin with a maximal capacity 50 times higher than in human serum. All these differences did not favor transport of iodinated compounds from maternal serum to milk. In conclusion, milk iodide was taken up by newborn thyroid to make thyroid hormones.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID