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Biomedical subjects

R Schott

Publications and source records attributed to R Schott.

17 recordsLinked to original sources
PubMed1999

A randomized trial of nocturnal oxygen therapy in chronic obstructive pulmonary disease patients.

The beneficial effects of nocturnal oxygen therapy (NOT) in chronic obstructive pulmonary disease (COPD) patients with mild-to-moderate daytime hypoxaemia (arterial oxygen tension (Pa,O2) in the range 7.4-9.2 kPa (56-69 mmHg)) and exhibiting sleep-related oxygen desaturation remains controversial. The effectiveness of NOT in that category of COPD patients was studied. The end points included pulmonary haemodynamic effects after 2 yrs of follow-up, survival and requirement for long-term oxygen therapy (LTOT). Seventy-six patients could be randomized, 41 were allocated to NOT and 35 to no NOT (control). The goal of NOT was to achieve an arterial oxygen saturation of >90% throughout the night. All these patients underwent polysomnography to exclude an associated obstructive sleep apnoea syndrome. The two groups exhibited an identical meansD daytime Pa,O2 of 8.4+/-0.4 kPa (63+/-3 mmHg) at baseline. Twenty-two patients (12 in the NOT group and 10 in the control group, p=0.98) required LTOT during the whole follow-up (35+/-14 months). Sixteen patients died, nine in the NOT group and seven in the control group (p=0.84). Forty-six patients were able to undergo pulmonary haemodynamic re-evaluation after 2 yrs, 24 in the NOT and 22 in the control group. In the control group, mean resting pulmonary artery pressure increased from 19.8+/-5.6 to 20.5+6.5 mmHg, which was not different from the change in mean pulmonary artery pressure in the NOT group, from 18.3+/-4.7 to 19.5+/-5.3 mmHg (p= 0.79). Nocturnal oxygen therapy did not modify the evolution of pulmonary haemodynamics and did not allow delay in the prescription of long-term oxygen therapy. No effect of NOT on survival was observed, but the small number of deaths precluded any firm conclusion. These results suggest that the prescription of nocturnal oxygen therapy in isolation is probably not justified in chronic obstructive pulmonary disease patients.

Follow-Up Studies↗
PubMed1999

Improvement of pulmonary hypertension after liver transplantation.

Pulmonary hypertension at the end stage of chronic liver disease is not an uncommon situation. This association termed portopulmonary hypertension raises the question of the feasibility of performing orthotopic liver transplantation (OLT). In the case reported herein, there was a favorable outcome after OLT, even though the mean pulmonary artery pressure (MPAP) before transplantation was increased to 45 mm Hg. Before OLT, the cardiac index (CI) was considerably elevated (7.69 L/min/m2), giving evidence of a marked hyperdynamic circulatory state. The CI decreased significantly after OLT (3.38 L/min/m2), and this produced a significant decrease in the MPAP. Our observation suggests that portopulmonary hypertension due to a marked increase in the CI can be managed successfully by OLT.

Adult↗
PubMed1999

[Paraneoplastic hypercorticism associated with a bronchial adenocarcinoma].

Cushing's syndrome is infrequently associated with adenocarcinomas of the lung. We present the clinical features of this syndrome in one case report. The pathogenesis of the syndrome explains the clinical signs, rather different from classical Cushing's disease and also the highly suggestive biological features. Ketoconazole improves clinical signs and biological abnormalities when etiological treatment is not effective.

Adenocarcinoma↗
PubMed1998

[Short-duration nocturnal hypoxemia and persistent pulmonary hypertension].

Can daily short-duration hypoxemia (4-8 hours) induce pulmonary hypertension and right ventricular hypertrophy? A clinical model of this type of hypoxemia does exist: isolated nocturnal hypoxemia in patients with obstructive sleep apnea syndrome (OSAS) or chronic obstructive pulmonary disease (COPD). By investigating the pulmonary hemodynamics of these patients, it should be possible to determine whether nocturnal hypoxemia alone can induce pulmonary hypertension. Although nocturnal hypoxemia (in OSAS as well as in COPD) can induce acute episodes of pulmonary hypertension, it would not appear that nocturnal hypoxemia alone would be sufficient to provoke permanent diurnal pulmonary hypertension. This is the conclusion of recent studies concerning diurnal pulmonary hemodynamics in OSAS and COPD patients exhibiting minimal hypoxemia during the day but significant nocturnal desaturation. The therapeutic consequences of these data, particularly in COPD are important: current evidence is insufficient to treat with nocturnal oxygen therapy COPD patients who have minimal diurnal hypoxemia but significant nocturnal desaturation.

Hemodynamics↗
PubMed1990

[Type I or IIa early stomach carcinoma. Comparative studies of the prognosis following limited or radical therapy].

In a retrospective study of 190 patients with type I (n = 100) or type IIa (n = 90) early gastric carcinoma, we investigated the question as to whether after limited therapy--endoscopic polypectomy (n = 49), large forceps biopsy (n = 4) or local surgical excision (n = 14)--or surgical resection (n = 123), differences in prognosis are to be found between the groups. In comparison with the age-adjusted 5-year survival rate, no differences were found between the limited therapy group and the resected group. Postoperative mortality was 3.0% in the limited therapy group and 17.1% in the resected group. Up to the fourth year of follow-up the prognosis was better for malignancy grade 1 than for malignancy grade 2 or 3, and also for tumours with a diameter of less than 3 mm than for those with larger diameters. No difference in 5-year survival rates was to be found with respect to the histological classification, depth of invasion, gross tumour type or multiple tumours. The results of these investigations indicate that limited treatment can be considered for type I or type IIa early gastric carcinoma when the carcinoma is restricted to the mucosa and is of the intestinal cell type of malignancy grade 1 or 2.

Adult↗
PubMed1987

Heterogeneity in the carbohydrate structure of rat angiotensinogen.

Angiotensinogen (Ao), the precursor of the peptide hormone angiotensin, exists in two different forms in plasma, Ao-1 and Ao-2. The completely separated and purified molecules show distinct differences in sodium dodecyl sulfate (SDS)-disc electrophoresis and in analytical isoelectric focusing. Ao-1 is about 3500 Da heavier and contains more acid isoelectric points than Ao-2. In analytical isoelectric focusing Ao-1 displays five bands which overlap with two of the three bands of Ao-2. This difference in charge was eliminated by treatment with neuraminidase for 92 h at 37 degrees C. Thereafter both molecules display an identical-pattern two bands in isoelectric focusing. Treatment of these N-acetylneuraminic acid (NeuNAc)-free forms with renin leads to a shift of these double bands to a more acid pH, indicating heterogeneity within the protein structure. By affinity chromatography on concanavalin A (ConA)-Sepharose, both forms can be separated in three fractions. The analysis of these fractions and of their NeuNAc-free derivatives by SDS-disc electrophoresis, as well as by analytical isoelectric focusing, leads to the conclusion that Ao-1 contains two Asn-linked N-glycan residues with 4-8 mol of NeuNAc, while the smaller form, Ao-2, contains one carbohydrate residue with 2-4 mol of NeuNAc.

Angiotensinogen↗
PubMed1987

Differences in pattern of plasma angiotensinogen in native and nephrectomized rats.

Rat plasma contains two distinct forms of angiotensinogen (Ao-1 and Ao-2) that can be found in single animals in a distinct ratio. The ratio of Ao-1 to Ao-2 was determined by separation of Ao-1 and Ao-2 from 1 ml of plasma from individual rats on an SP-Sephadex C-50 column. Plasma from rats of three different strains, Wistar, Wistar-Kyoto (WKY), and spontaneously hypertensive rats (SHR), was investigated. In Wistar rats native plasma contained Ao-1 and Ao-2 in a ratio of 2.6:1. Twenty-four hours after nephrectomy, which increased the total Ao content 4.1-fold, this ratio was changed to 1.1:1. In native WKY and SHR the ratio of the two forms was similar to that in Wistar rats: 2.4:1 and 2.8:1, respectively. After nephrectomy the ratio of Ao-1 to Ao-2 was changed to 1.1:1 and 0.78:1 in WKY and SHR, respectively, while the total Ao content increased 4.9-fold and 8.2-fold in the two strains. Endogenous plasma renin inactivated the two forms of Ao, with a Km of 4.0 +/- 0.46 and 3.7 +/- 0.43 microM and a Vmax of 176 +/- 15.5 and 155 +/- 12.7 nM/hr, respectively. These results suggest that 1) Ao-1 and Ao-2 are synthesized in equimolar amounts, 2) the clearance of Ao-2 is faster than that of Ao-1 in control rats, and 3) under conditions of stimulated synthesis (i.e., after nephrectomy), the plasma content of Ao-2 increases faster than that of the more highly glycosylated form, Ao-1.

Angiotensinogen↗
PubMed1987

Renin-angiotensin system in sepsis.

The time course of the components of the renin-angiotensin system was investigated in the plasma of three patients on the intensive care unit. Two of them, which were both polytraumatized, suffered from adult respiratory distress syndrome (ARDS). All patients had sepsis and impaired pulmonary and renal function. Plasma samples were investigated for up to two weeks, in which time all three patients showed a decrease in their angiotensin converting enzyme (ACE) plasma concentration. Two of the patients with deteriorating renal function had three to four times elevated angiotensinogen (Ao) plasma levels, which were measured by both the direct and indirect radioimmunoassay. The ratio of the mean values between both assays was 1:1 in two patients and shifted to higher values in the direct assay in the third patient. This suggests that higher amounts of des-AngI-angiotensinogen were present in the latter patient, because "inactive" Ao is also detected by the direct assay. The decrease in active Ao may be caused by an up to twenty times elevated plasma renin activity (PRA). The PRA was correlated with the angiotensin I (AngI) plasma levels. However, at PRA values higher than 200 pmol AngI/ml/h this correlation decreased because of the rapid substrate consumption. In addition there was a good correlation between AngI and AngII plasma levels in two patients which could not be observed in the patient with the highest PRA and AngII values. A relationship between plasma ACE concentration and AngII formation could not be observed. Thus in two of the three septic patients the components of the renin angiotensin system were extremely stimulated at very low blood pressure values. These data show, that it is reasonable to follow the time course of the components of the renin angiotensin system in single patients. In addition it is demonstrated that the direct measurement of Ao is a valid supplement in the diagnosis of the renin angiotensin system.

Acute Kidney Injury↗
PubMedDate not supplied

A rapid method for determining the sterility of frozen-reconstituted blood.

A rapid, fast, and accurate method of determining bacterial contamination in blood units is needed to provide a safe unit of frozen-reconstituted blood which can be stored at 4 C after thawing for more than the 24 hours currently allowed by law. The Bactec instrument seems to provide this method. It detects most of the organisms which have been reported in contamineted blood, and does this in a short enough period of time that any organisms introduced into the blood unit during the sampling process will not grow sufficiently to contaminate the unit while the culturing process is going on.

Bacteriological Techniques↗
PubMedDate not supplied

Studies on 4 C stored frozen-reconstituted red blood cells. I. Bacterial growth.

A knowledge of the growth rates of various organisms at the storage temperature of 4 C in the different suspending media used for red blood cells would aid the extension of the thawed storage time of frozen-reconstituted blood beyond the 24 hours allowed by the Food and Drug Administration. Knowing these rates, a prediction could be made that the growth rate would be sufficiently slow and the unit (sterile or minimally contaminated) could be given safely after a longer storage period. The studies reported show that the pathogenic organisms S. aureus, Ps. aeruginosa, E. coli, Klebsiella sp. and Enterobacter sp. grow at such a slow rate at 4 C that they do not represent any great hazard to the recipient unless introduced in great numbers. The studies further show that in the process of washing frozen blood the number of organisms is reduced by between one and two orders of magnitude (base 10). Therefore, extension of frozen red blood cell storage life to at least 72 hours should be considered.

Bacteriological Techniques↗
PubMedDate not supplied

Studies on 4 C stored frozen-reconstituted red blood cells. III. Changes occurring in units which have been repeatedly frozen and thawed.

Units of frozen red blood cells were thawed, stored at 4 C for varying amounts of time up to five days, and then subsequently refrozen. This procedure was repeated for two or three cycles. Chemical and cytological studies showed that only a moderate number of red blood cells were lost and that the red blood cells would be transfusable with minimal danger to the patient. The units retained their sterility despite all of the manipulations. The ability to refreeze a unit of blood would extend the value of frozen blood greatly by preventing the loss of very rare units.

Blood Preservation↗
PubMedDate not supplied

An aseptic fluid transfer system for blood and blood components.

A device is described which can be attached to all blood bags. Two of these devices are heat-sealed together aseptically at any time during the storage life of the blood unit, and an opening connecting the two is created. In vitro and in vivo studies show that ten passes of a unit of blood through these devices produces no cytological changes and does not alter the in vivo survival of the unit when transfused. Further, if the unit is frozen, then thawed, and even stored at 4 C for five days after thawing, the in vivo survival is still unaffected.

Blood Banks↗