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Biomedical subjects

D Weismann

Publications and source records attributed to D Weismann.

10 recordsLinked to original sources

Adrenocortical carcinoma -- improving patient care by establishing new structures.

BACKGROUND: Adrenocortical carcinoma (ACC) is a rare and highly malignant tumour with a poor prognosis. Patients present with signs of steroid hormone excess (e.g., Cushing's syndrome) or symptoms due to an abdominal mass. DIAGNOSIS: In case of an adrenal mass, hormonal workup before surgery is required for differential diagnosis, perioperative management, and for follow-up. The imaging of choice is CT or MRI with MRI being of additional use when invasion of big vessels is suspected. Apart from that, the use of 18-FDG-PET is becoming increasingly established. TREATMENT: Surgical resection is the therapeutic option of choice in stages 1 - 3. In stage 4, the adrenolytic compound mitotane is part of the first-line treatment, but often needs to be combined with cytotoxic chemotherapy. Most patients will eventually have a recurrence, so adjuvant treatment (mitotane/tumour bed radiation) has to be considered in high risk patients, even if randomized controlled trials on adjuvant treatment are still lacking. STRUCTURAL PROGRESS: Several national and European structures have recently been established in order to increase our knowledge of ACC, improve therapeutic options and diagnostic procedures, and promote research. GANIMED, as a Germany-wide network of experts on adrenal diseases, has been founded allowing for improved gathering of data and joint studies. ENSAT (European Network for the Study of Adrenal Tumours) has been brought to life, aiming at European standards for therapy, diagnosis and tumour banking. Since 2003, patients can be enrolled in the German ACC Registry. France and Italy have also developed a central registry to collect nationwide data from patients with ACC. For the first time, patients with metastatic/unresectable ACC can participate in a prospective controlled randomized trial comparing two different cytotoxic chemotherapy regimes (FIRM-ACT).

Adrenal Cortex Neoplasms↗

Estimation of pulmonary blood flow from sinusoidal gas exchange during anaesthesia: a theoretical study.

We simulated the use of simultaneous sinusoidal changes of inspired O2 and N2O (Williams et al., J Appl Physiol, 1994; 76: 2130-9) at fractional concentrations up to 0.3 and 0.7, respectively, to estimate FRC and pulmonary blood flow (PBF) during anaesthesia, using O2 as an insoluble indicator. Hahn's approximate equations, which neglect the effect of pulmonary uptake and excretion on expiratory flow, estimate dead space and alveolar volume (VA) with systematic errors less than 10%, but yield systematic errors in PBF which are approximately proportional to FIN2O in magnitude. A correction factor (1 - P)-1 for Hahn's equations for PBF (where P is the mean partial pressure of the soluble indicator) reduces the dependence of PBF estimates of FIN2O, and the solution of equations describing the simultaneous mass balance of both indicators yields accurate results for a wide range of mean FIN2O. However, PBF estimates are sensitive to measurement errors and a third gas must be present to ensure that the indicator gases behave independently.

Anesthesia↗

Time course evolution of ventilatory responses to inspiratory unloading in patients.

Inspiratory muscle unloading decreases ventilatory drive. In this study, we examined the time course of this effect in patients with chronic obstructive pulmonary disease receiving two modes of ventilatory support: pressure support ventilation (PSV), during which each cycle was assisted, and biphasic positive airway pressure (BIPAP), set up in such a manner that one spontaneous breath took place between two consecutive pressure-assisted breaths. The first breath following the switch from spontaneous breathing to PSV was associated with an increase in tidal volume (VT) and a drop in mean transdiaphragmatic pressure (mean Pdi) and inspiratory work (WI) performed per liter but with unchanged values of esophageal occlusion pressure at 100 ms (Pes 0.1), diaphragmatic electrical activity (EMGdi), and WI performed by breath. The same phenomena were observed for the assisted breath of BIPAP as compared with the preceding spontaneous breath. During the subsequent breaths of PSV, Pes 0.1, EMGdi, and WI performed per breath decreased progressively up to the sixth to eighth breaths, and VT returned to pre-PSV values. We conclude that in patients with chronic obstructive pulmonary disease the decrease in ventilatory drive associated with PSV takes place from the first breath onwards but requires six to eight breaths to be fully achieved. During BIPAP, as a consequence of the kinetics of the PSV-induced downregulation of ventilatory drive, assisted breaths following spontaneous breaths are characterized by an enhanced inspiratory efficiency.

Aged↗

Lead intoxication in Iowa children.

In Iowa, there are over 600,000 residential units built before 1950 which are high risk environments for children due to deteriorating lead paint. However, there are relatively few lead screening programs in Iowa, and only selected children in Iowa have been screened.

Age Factors↗

Use of hemoperfusion for treatment of theophylline intoxication.

We review our experience in the management of patients with plasma theophylline concentrations of 30 micrograms/ml or greater. Over a two-and-a-half-year period, 22 patients (Group 1) had plasma theophylline concentrations of 37 +/- 1 micrograms/ml (mean +/- SE) and experienced no severe toxicity (i.e., ventricular extrasystoles or tachycardia, seizures, cardiovascular collapse, or death). Six patients (Group 2) took overdoses of theophylline (92 +/- 12 micrograms/ml) and one died. Eight patients (Group 3) were iatrogenically intoxicated (48 +/- 6 micrograms/ml) and three died. Six patients from Groups 2 and 3 underwent hemoperfusion and did well, except for one patient, in whom seizures developed before hemoperfusion was initiated. We conclude from this experience that charcoal hemoperfusion is a useful procedure for the treatment of theophylline intoxication because of: (1) the serious morbidity and mortality of theophylline intoxication, (2) the prevention of complications with hemoperfusion, and (3) the relative safety of the procedure. We provide tentative guidelines for the initiation of hemoperfusion for the treatment of theophylline intoxication.

Adolescent↗

Tissue distribution of gentamicin in lambs: effect of postnatal age and acute hypoxemia.

Gentamicin tissue distribution and uptake were studied in chronically catheterized lambs in relation to their possible role in postnatal age- and hypoxemia-related effects on serum gentamicin concentration. Gentamicin serum concentration (SGent) was proportional to dose and was paralleled by gentamicin delivery to specific organ tissues (DGent) and tissue gentamicin content (TGent). SGent per dose was higher in older lambs (2-5 weeks of age) and in hypoxemic (pO2 36 +/- 7 Torr) lambs. DGent to liver, heart and adrenal tissues per unit dose was increased in response to hypoxemia. TGent paralleled SGent under these conditions. Hypoxemia- and age-related effects on SGent were not explained by differences in TGent in these lambs.

Aging↗

Role of aldosterone on renal sodium and potassium excretion during fetal life and newborn period.

The renal response to endogenous aldosterone production at different times during gestation and immediately after birth, as well as factors controlling aldosterone secretion during fetal life have been studied in 34 lamb fetuses (106-142 days of gestation, term 145 days) and in 6 newborn lambs (3-8 days postnatal age). It was demonstrated that the increase in fetal plasma aldosterone concentrations correlated with the increase in fetal plasma renin activity (PRA) (r = 0.67, p < 0.001). Moreover, it was fond that the slope of the regression line between plasma aldosterone and PRA during fetal life was significantly steeper (p < 0.05) than after birth. Significant correlation coefficients were found between the fetal urinary to plasma ratios (U/P) of sodium over potassium [(U/P)Na+/(U/P)K+] and either fetal plasma aldosterone (r = -0.53, p < 0.005) or fetal age (r = -0.52, p < 0.005). Moreover, in 7 out of 9 fetuses over 125 days, frank secretion of potassium by the fetal tubular cells was demonstrated; such a secretion was present in only 1 of the 15 fetuses between 101 and 125 days of gestation. Finally, it was demonstrated that the increase in mean arterial blood pressure during fetal life and after birth is not a major factor in the increase in fetal glomerular filtration rate during gestation or in the adaptation of glomerular filtration rate to extrauterine life.

Aldosterone↗