Biomedical subjects

A Hamvas

Publications and source records attributed to A Hamvas.

At least 37 records · Page 2Linked to original sources

PubMed1996

The influence of the wider use of surfactant therapy on neonatal mortality among blacks and whites.

BACKGROUND: Surfactant therapy reduces morbidity and mortality among premature infants with the respiratory distress syndrome (RDS). Fetal pulmonary surfactant matures more slowly in white than in black fetuses, and therefore RDS is more prevalent among whites than among blacks. We reasoned that the increased use of surfactant after its approval by the Food and Drug Administration (FDA) in 1990 might have reduced neonatal mortality more among whites than among blacks. METHODS: We merged vital-statistics information for all 1563 infants with very low birth weights (500 to 1500 g) born from 1987 through 1989 or in 1991 and 1992 to residents of St. Louis with clinical data from the four neonatal intensive care units in the St. Louis area; we then compared neonatal mortality during two periods, one before and one after the FDA's approval of surfactant for clinical use (1987 through 1989 and 1991 through 1992). RESULTS: The use of surfactant increased by a factor of 10 between 1987 through 1989 and 1991 through 1992. The neonatal mortality rate among all very-low-birth-weight infants decreased 17 percent, from 220.3 deaths per 1000 very-low-birth-weight babies born alive (in 1987 through 1989) to 183.9 per 1000 (in 1991 through 1992; P = 0.07). This decrease was due to a 41 percent reduction in the mortality rate among white newborns with very low birth weights (from 261.5 per 1000 to 155.5 per 1000; P = 0.003). In contrast, among black infants, the mortality rate for very-low-birth-weight infants did not change significantly (195.6 per 1000 and 196.8 per 1000). The relative risk of death among black newborns with very low birth weights as compared with white newborns with similar weights was 0.7 from 1987 through 1989 and 1.3 from 1991 through 1992 (P = 0.02). The differences in mortality were not explained by differences in access to surfactant therapy, by differences in mortality between black and white infants who received surfactant, or by differences in the use of antenatal corticosteroid therapy. CONCLUSIONS: After surfactant therapy for RDS became generally available, neonatal mortality improved more for white than for black infants with very low birth weights.

Adrenal Cortex Hormones↗

PubMed1995

Pathophysiology and treatment of surfactant protein-B deficiency.

Surfactant protein B (SP-B) deficiency is an inherited disease of full-term newborn infants which leads to lethal respiratory failure within the first year of life. Genetic analysis of affected infants has permitted identification of a mutation in the SP-B gene found in several unrelated kindreds which disrupts pulmonary surfactant composition and function. Lung transplantation has resulted in reconstitution of pulmonary surfactant function and long-term survival. SP-B deficiency represents the first opportunity to link physiologic characteristics of respiratory failure in infancy with specific molecular and cellular defects. This linkage will facilitate development of novel strategies for the treatment of neonatal respiratory diseases.

Genetic Therapy↗

PubMed1994

[ESWL in renal tubular acidosis].

ESWL is a suitable modality for the management of lithiasis caused by RTA, especially in case of renal or ureteric stones. Smash of calculi in ducts of Bellini is worthy to be considered if the fragments can get into the renal pelvic space and the renal function improve. At present it is still a matter of discussion.

Acidosis, Renal Tubular↗

PubMed1994

Surfactant protein B deficiency: antenatal diagnosis and prospective treatment with surfactant replacement.

An infant with a family history of congenital alveolar proteinosis associated with surfactant protein B (SP-B) deficiency was identified when SP-B was not detected in amniotic fluid obtained at 37, 38, and 40 weeks of gestation. Surfactant replacement with commercially available preparations that contained SP-B was begun soon after delivery. Progressive respiratory failure developed despite continued surfactant replacement, corticosteroid therapy, and extracorporeal membrane oxygenation. The infant died at 54 days of age while awaiting lung transplantation. Surfactant extracted from amniotic fluid, bronchoalveolar lavage fluid, and lung tissue had no phosphatidylglycerol; surface tension was 24 dynes/cm (normal, < 10 dynes/cm) and did not decrease with in vitro addition of exogenous SP-B. Pulmonary vascular permeability measured with positron emission tomography was twice normal. At autopsy the alveolar proteinosis pattern was less prominent than that seen in affected siblings. Immunoreactivity of SP-B was absent in type II cells, but numerous foreign body granulomas with central immunoreactivity for SP-B and surfactant protein C were present. We conclude that exogenous surfactant replacement did not normalize surfactant composition, activity, or pulmonary vascular permeability. These findings suggest that endogenous SP-B synthesis is necessary for mature surfactant metabolism and function.

Amniotic Fluid↗

PubMed1994

Bronchial and reverse pulmonary venous blood flow protect the lung from ischemia-reperfusion injury.

We used an intact in vivo canine model of pulmonary ischemia-reperfusion injury to evaluate whether the bronchial circulation or reverse pulmonary venous blood flow would protect the lung from injury during 2 h of unilateral pulmonary arterial (PA) occlusion and lung deflation. Serial measurements of regional extravascular density and transcapillary protein flux were made after reperfusion by using the quantitative imaging technique of positron emission tomography. Twenty-one animals were divided into four experimental groups. In all experimental groups, the left PA was clamped and the left lung was allowed to collapse and remain unventilated for a period of 2 h. In addition, in group I (n = 5) the left bronchial circulation was disrupted and the left pulmonary veins were clamped, in group II (n = 5) the bronchial circulation and the pulmonary veins were left intact, in group III (n = 6) the bronchial circulation was left intact but the pulmonary veins were clamped, and in group IV (n = 5) the bronchial circulation was disrupted but the pulmonary veins remained patent. The rate of protein flux in the left lung was increased only in group I (complete ischemia with lung deflation) [mean 195 x 10(-4) min-1 (range 85-453 x 10(-4) min-1) at 0.25 h and 114 x 10(-4) min-1 (range 22-200 x 10(-4) min-1) at 3 h] after reventilation and PA reperfusion (normal = 49 +/- 31 x 10(-4) min-1). Extravascular density increased significantly from 0.25 to 3 h only in group I.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Ultrastructure of lung in surfactant protein B deficiency.

Congenital alveolar proteinosis (CAP), a cause of respiratory failure in fill-term newborns, often leads to death in infancy despite medical therapy. We recently described an inherited deficiency of surfactant protein B (SP-B) (N. Engl. J. Med. 1993; 328:406-410) in two siblings with CAP. The SP-B deficiency was accompanied by marked abnormalities, both quantitative (increase) and qualitative (distribution), of SP-A and SP-C in the lungs of the affected infants. Ultrastructural studies of the lung of one of these infants and of a third affected sibling born in the index family showed abundant alveolar concentric multilamellated structures and membranous vesicles but no typical tubular myelin. In addition, membranous vesicles from type II cells and immunogold labeled SP-A and SP-C were found between type II cells and their basement membrane despite intact interepithelial cell junctions. These findings suggest an important role for SP-B in the directionality of surfactant secretion and in the formation of tubular myelin.

Autopsy↗

PubMed1993

[Complex therapy of cystine calculi].

Authors report their experiences with management of cystine urolithiasis between 1975-1992. 61 patients were observed and treated with dietotherapy, medicaments, open surgery, percutaneous nephrolithotomy and extracorporeal shock wave lithotripsy. Difficulties of treatment of this rare stone have been demonstrated with data of 3 patients (lack of screening and early diagnosis, unsystematic prophylaxis, formation of large stones).

Adolescent↗

PubMed1993

[Successful shock wave monotherapy of coral-shaped calculi in the kidney calix].

Authors reported about two patients with staghorn calculi, who have been treated by extracorporeal shock wave monotherapy by Direx Tripter-X-1 Lithotripter. They used in the first case percutaneous nephrostomy, in the second double J catheter as auxiliary method. Patients were treated 3 and 4 time, and they were stone free at three month follow up.

Adult↗

PubMed1993

Surfactant therapy failure identifies infants at risk for pulmonary mortality.

OBJECTIVE: To characterize the clinical features of infants who do not respond to surfactant therapy. DESIGN: Patient series, chart review. SETTING: Academic referral neonatal intensive care unit. PATIENTS/SELECTION: Ninety-nine consecutive infants with respiratory distress syndrome who received surfactant therapy and 107 infants from the 2 years prior to initiation of surfactant therapy matched for birth weight, race, sex, gestational age, chronological age, and disease severity. MEASUREMENTS/RESULTS: Oxygen index was used to quantitate response to surfactant therapy. A 25% decrease in oxygen index 6 hours after the first surfactant dose was significantly different from that of the matched historical cohort (P = .04). Oxygen index decreased 25% or more in 49 infants, the response group, while oxygen index decreased less than 25% or increased following therapy in the remaining 50 infants, the nonresponse group. Pulmonary interstitial emphysema occurred more frequently in the nonresponse group. The only deaths from pulmonary causes at 10 days of age or younger occurred in the nonresponse group (n = 11). CONCLUSIONS: Pulmonary processes unresponsive to surfactant therapy contribute to morbidity and mortality in newborn respiratory distress syndrome. Classifying respiratory distress syndrome as "surfactant responsive" or "surfactant unresponsive" offers a scheme by which to investigate alternative explanations and interventions for newborn respiratory distress syndrome.

Female↗

PubMed1993

The role of Melipramine in the treatment of bladder instability.

Observations with Melipramine (imipramine) coated tablet used in the treatment of bladder instability are reported. The patients were selected on the basis of urodynamic examinations. Five men and 45 women were treated for 2 and 4 weeks. The patients recorded the number of urinations and urgency as well as the quantity of voided urine. The effectivity of treatment was controlled by urodynamic examinations. Melipramine (3 x 2 coated tablet) given in 60-mg daily doses, favourably influenced the symptoms. The effectivity of treatment reached 90% in the selected patients. Side-effects developed in 5 cases: in 3 patients the treatment had to be discontinued because of palpitation, feeling weakness. According to the authors' opinion Melipramine is a useful therapeutic means in the treatment of bladder instability.

Drug Evaluation↗

PubMed1992

[Experience with the Direx Tripter X-1].

In nonselected patients 81.5% stone-free rate could be reached in 3 months. In authors's opinion Direx Tripter X-1 is suitable in the treatment of renal and ureteral calculi. They treated staghorn calculi by ESWL monotherapy with success. The Direx lithotripter was found to be effective and easy to operate; the potential cost reduction is of great significance. The treatment requires general anaesthesia and the equipment causes significant noise. After all, Direx lithotripter is a useful machine in the armamentarium of stone disease treatment.

Adolescent↗

PubMed1992

Experience with the Direx Tripter X-1 shock-wave lithotripter.

The authors give account of the experience they gained with the Direx Tripter X-1 (ESWL) apparatus. In a random material they succeeded to render 81.5% of the patients stone free within three months. They judge the apparatus suitable for in situ treatment of pelvic and ureteric stones and for the monotherapy of staghorn calculi. It is easy to handle, inexpensive to buy and maintain but noisy to operate, moreover the patient has to be anaesthetized. All in all it is highly useful in the treatment of renal lithiasis.

Adolescent↗

PubMed1992

Injury in nonischemic lung after unilateral pulmonary ischemia with reperfusion.

We developed an in vivo intact canine model to study pulmonary ischemia-reperfusion (IR) injury. The surgical approach simulates that of unilateral lung transplantation but is free of technical difficulties and other factors related to lung preservation. Serial measurements of regional pulmonary blood flow (rPBF), extravascular density (EVD), and transcapillary protein flux were made with the quantitative imaging technique of positron emission tomography. Eleven experimental and six control animals were studied. After 2 h of warm ischemia followed by reperfusion, no significant change occurred in rPBF despite significantly increased EVD, which was greater on the ischemic than on the nonischemic side. Protein flux, measured as a rate constant, was also greater on the ischemic than on the nonischemic side (median 181 x 10(-4)/min, range 104-619, vs. median 90, range 33-132) immediately after reperfusion. Both sides were also significantly different from control values (median 37, range 21-57). On both sides, protein flux decreased over time and at 5 h after reperfusion was not different from that of controls. Data from the control animals showed that these findings in the experimental animals were not due to surgical technique, deterioration in the surgical preparation, or hyperperfusion of the nonischemic lung. Thus IR injury of one lung can lead to similar, but less severe, injury in the contralateral lung. Because injury in the nonischemic lung develops only after reperfusion of the ischemic lung, injury to the nonischemic lung is probably humorally mediated. The model is a useful and relevant method for studying the physiological consequences of pulmonary IR injury.

Animals↗

PubMed1992

Inflammation and oxygen free radical formation during pulmonary ischemia-reperfusion injury.

In a companion study, we showed that 2 h of warm unilateral lung ischemia followed by reperfusion resulted in bilateral tissue injury, indicated by increases in extravascular density (EVD) and permeability, measured as the pulmonary transcapillary escape rate (PTCER) for radiolabeled transferrin. EVD and PTCER measurements were obtained with the quantitative imaging technique of positron emission tomography (PET). In the current study, we evaluated this increase in EVD histologically and correlated EVD and PTCER with measurements of oxidant-reactive sulfhydryls (RSH) in plasma as a marker of oxygen free radical (OFR) formation. Histologically edema, leukocyte infiltration, and hemorrhage were all present on the ischemic side, but only after reperfusion, whereas only neutrophil infiltration was observed on the nonischemic side. Histology scores correlated with EVD (r = 0.81) and PTCER (r = 0.75), but permeability was abnormal at times even in the absence of neutrophil infiltration. Plasma RSH concentration from the ischemic lung decreased significantly (P less than 0.05) during pulmonary ischemia (i.e., before reperfusion) and returned to baseline on reperfusion. The degree of RSH oxidation did not correlate with the severity of injury as measured by PET or histology. Thus pulmonary ischemia-reperfusion injury is characterized by inflammation, hemorrhage, edema, and OFR formation. Injury occurred after reperfusion, not after ischemia alone. In addition, injury to the contralateral nonischemic lung suggests a neutrophil-independent circulating mediator of injury.

Animals↗

PubMed1992

Modifying pulmonary ischemia-reperfusion injury by altering ventilatory strategies during ischemia.

We used an intact in vivo canine model of pulmonary ischemia-reperfusion (IR) injury to evaluate the differential effects of alveolar hypoxia and ventilation during 2 h of unilateral warm lung ischemia. Serial measurements of regional pulmonary blood flow, extravascular density (EVD), and transcapillary protein flux were made after reperfusion with the quantitative imaging technique of positron emission tomography. Twenty-seven animals were divided into five experimental groups: VENT O2 (n = 5) in which the left lung was ventilated with 40% O2 during ischemia, STATIC O2 (n = 4) in which the left lung was statically inflated with 40% O2 during ischemia, VENT N2 (n = 5) in which the left lung was ventilated with 100% N2 during ischemia, VENT N2/CO2 (n = 5) in which the left lung was ventilated with 95% N2-5% CO2 during ischemia, and STATIC N2 (n = 8) in which the left lung was statically inflated with 100% N2 during ischemia. These groups were compared with a control group (CONT, = 3) that was studied previously. Protein flux was significantly increased in the previous ischemic lung only for the STATIC N2 group [median 175 x 10(-4) min-1 (range 53-1,217) for the STATIC N2 group vs. 50 x 10(-4) min-1 (range 40-56) for the CONT group] 0.25 h after reperfusion and did not change over 3 h. EVD also increased but not significantly. Protein flux and EVD in the other groups were not different from CONT.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗

PubMed1992

The effects of regional pulmonary blood flow on protein flux measurements with PET.

We used PET to evaluate whether changes in regional pulmonary blood flow (PBF) or plasma volume (PV) affect calculations of the pulmonary transcapillary escape rate (PTCER) for 68Ga-labeled transferrin. We reduced PBF in five dogs by inflating a right atrial balloon. Regional PBF decreased 25% to 174 +/- 40 ml/min/100 ml lung without a change in PV or PTCER. In eight other dogs, we decreased PBF and PV via controlled arterial hemorrhage. PBF decreased 45% to 110 +/- 33 ml/min/100 ml lung and PV decreased 22% without a change in PTCER. We also used a series of computer simulations to evaluate the effect of even greater reductions in regional PBF on PTCER calculations. These simulations showed, in support of the experimental data, that if PBF was greater than 40 ml/min/100 ml lung, PTCER could be accurately measured. However, below this level, PV was increasingly under-estimated and PTCER overestimated. The results indicate the sensitivity of the PTCER calculation to errors in the PV measurement, especially in regions of markedly reduced regional PBF.

Animals↗

PubMed1991

Experience with the Peponen capsule in the management of benign prostatic hyperplasia.

Sixty patients in Stages I and II of benign prostatic hyperplasia were treated with Peponen capsule. Out of them 26 took the drug for 10 months, 22 for at least 7, and 12 for at least 4 months. The daily dosage was 3 x 2 capsules in the first month and 3 x 1 capsule for the rest of the time. On the ground of urodynamic test results and changes in subjective complaints, more than 80% of the patients experienced improvement. The therapy intensified the uroflow, appeased dysuria, the difficult and painful discharge, and reduced the frequency of nocturnal urination.

Humans↗

PubMed1990

[Double kidney and ureterocele associated with kidney calculi].

The simultaneous occurrence of infrequent alterations--double kidney, ureterocele and calculi--is reported. Following the operation performed in 2 steps the patient became free of complaints and according to the repeated controls the dilatation of the efferent system regressed, no reflux was observed.

Abnormalities, Multiple↗