Effect of radiotherapy on brain glucose metabolism in patients operated on for low grade astrocytoma.

OBJECTIVE: To assess the effect of postoperative radiotherapy on brain glucose metabolism (CMRGlu) of operated patients with low grade astrocytomas. METHODS: PET and 18F-fluorodeoxyglucose was used to measure absolute CMRGlu in patients with fibrillary astrocytoma (WHO II) of the frontal lobe, who did (n=7) or did not (n=12) receive radiotherapy subsequent to first debulking tumour resection. In addition, statistical parametric mapping (SPM95) was applied to assess the pattern of relative CMRGlu associated with the frontal tumour. Data were compared with 12 healthy controls. RESULTS: A global reduction of absolute CMRGlu was found when either patients with or without radiotherapy were compared with controls (ROI analysis). Brain areas of relative CMRGlu reduction were found in the brain ipsilateral and contralateral to the tumour, comparing both patient groups with controls by SPM ("tumour diaschisis effect"). Superimposed, absolute CMRGlu in the contralateral frontal, parietal, occipital cortex as well as in the white matter was on average 17% lower in patients receiving radiotherapy than in patients who did not. CONCLUSIONS: The data discriminate a tumour effect from a radiotherapy effect, and support the view of adverse effects of radiotherapy on brain not directly involved by tumour.

The effects of bronchodilators on spontaneous ventilation and oxygen consumption in rhesus monkeys.

The effects of breathing normal saline, salmeterol, fenoterol, ipratropium bromide, or formoterol, and of i.v. infusion of theophylline on oxygen consumption (VO2), carbon dioxide production (VCO2), minute ventilation (VE), heart and respiratory rates, and end-tidal carbon dioxide tension (P(ET)CO2) have been defined in 10 anesthetized, intubated rhesus monkeys (mean age 7.0 y, weight 10.2 kg). VO2 increased over control by + 17.1% after salmeterol (p < 0.001), +33.3% after fenoterol (p < 0.001), +23.7% after formoterol (p < 0.001), +3.9% after theophylline (p < 0.01), but did not change after ipratropium bromide and normal saline. VE increased by 63.0% after fenoterol (p < 0.001), 49.8% after formoterol (p < 0.001), 31.7% after salmeterol (p < 0.01), and 29.7% after theophylline (p < 0.001), but not after ipratropium bromide or normal saline. Heart rate response was greatest after fenoterol, formoterol, and salmeterol, respectively. P(ET)CO2 dropped dramatically after theophylline (-15.7%, p < 0.001), but not at all with any of the inhaled beta2-adrenoceptor agonists. In seven animals, salbutamol (albuterol) caused an increase in V(E) and VO2 of 50.1% and 45.9%, respectively, whereas in the presence of a beta2-adrenoceptor antagonist [racemic or (+/-)-propranolol (0.1 mg/kg i.v.)], inhaled salbutamol (2.5 mg/mL for 10 min) could not increase V(E) (+6.2%, p > 0.05) and VO2 (+1.6%, p > 0.05). The increase in VO2 and V(E) after administration of beta2-agonists may be partly the result of direct stimulation of the respiratory center and partly a response to increased metabolic rate. The dramatic increase in VO2 and V(E) after salbutamol was suppressed in the presence of propranolol, which is consistent with a beta-receptor-mediated mechanism.

The effects of varying inflation and deflation pressures on the maximal expiratory deflation flow-volume relationship in anesthetized rhesus monkeys.

Deflation flow-volume curve analysis is a pulmonary function test sensitive to small airways dysfunction that is suitable for use in infants and children who are intubated. This test relies upon deflation flow-volume (DFV) curve analysis, which is a technique to obtain maximal expiratory flow-volume curves (MEFV) by forced deflation of the lungs in infants who are intubated. The method mimics the voluntary forced flow-volume curves that adults and older children undertake. We studied 10 anesthetized male Rhesus monkeys of the same weight as human infants but developmentally equivalent to older children. We reviewed the effects on forced deflation vital capacity (DVC) and flows at various subdivisions of vital capacity (PEF, MEF50, MEF25, MEF10) of systematically varying the required inspiratory and deflation pressure during the course of 56 consecutive deflation maneuvers. Inflation pressures of +40 and +50 cm H2O caused a marked but transient bradycardia along with a (probably spurious) short-lasting fall to 89% mean arterial oxygen saturation (SaO2). Increasing positive and negative pressures increased DVC and expiratory flows. The highest mean DVC was 75.6 +/- 1.3 ml/kg, PEF was 128.0 +/- 3.5, MEF50 was 85.9 +/- 2.2, MEF25 was 74.3 +/- 1.9, and MEF10 was 38.5 +/- 2.9 ml/kg/s, all obtained at the pressure gradient of 90 cm H2O (+50/-40 cm H2O) at the start of the deflation maneuver. At this gradient, the intraindividual coefficients of variation were: DVC = 0.8%, PEF = 3.1%, MEF50 = 2.2%, MEF25 = 2.1%, MEF10 = 5.4%.(ABSTRACT TRUNCATED AT 250 WORDS)

The ventilatory and oxygen costs in the anesthetized rhesus monkey of inhaling drugs used in the therapy and diagnosis of asthma.

We examined in male Rhesus monkeys the effects on oxygen consumption (VO2), carbon dioxide production (VCO2), minute ventilation (VE), heart and respiratory rates, and functional residual capacity (FRC) of breathing normal saline (NS), salbutamol (albuterol), methacholine (MCh), sodium cromoglycate (SCG), epinephrine (adrenaline), and terbutaline in doses commonly prescribed to human infants and children. We studied 10 anesthetized and intubated monkeys with a mean age and weight of 6.0 yr and 9.1 kg, respectively. VO2 increased over control, by 46.5% after salbutamol (p less than 0.0005), 25% after methacholine (p less than 0.001), 13.2% after epinephrine (p less than 0.01), and 16% after terbutaline (p less than 0.001), but it did not increase after either SCG or NS. VE increased by 82% after MCh and salbutamol (p less than 0.001), less dramatically after epinephrine and terbutaline at 50.5 and 31.5% (p less than 0.02 and p less than 0.001), respectively, and not at all after SCG and NS. Heart rate response was greatest after salbutamol, and nodal and ventricular arrhythmias were noted in four of 10 monkeys after MCh challenge. FRC did not change significantly except after salbutamol, where there was a small rise of 1.8 ml/kg (p less than 0.05).

Performance of a computerized CCU arrhythmia monitor system.

Experience gained during clinical trials at Johns Hopkins University Hospital has led to refinements in a commercial arrhythmia monitoring system. The performance capabilities and limitations are described for normal Coronary Care Unit use. The system evaluation spanned a time period of over 16 months and included 3,176 monitored patient days. The majority of both false and true arrhythmia alarms was found to be produced by two small, statistically independent segments of the patient population.

Morphologic studies in saphenous vein grafts for aorto-coronary bypass surgery. Part I: Morphology of the Graft using ordinary surgical preparation techniques.

Vein bypass grafts in 8 patients were examined by light microscopy (LM) only or, in addition, by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) before stretching, after stretching and immediately before implantation. Before stretching, the endothelium showed only discrete changes and detachment of the endothelium was rare. After stretching severe endothelial damage was evident, including loss of large areas of endothelium and extensive endothelial tears. Before implantation there had been an extension of the tears and the endothelial detachment in individual preparations. The most important factor causing damage is stretching of the vein. The incubation medium may also play a significant role. Damage incurred before operation or during removal, and hypoxia are of lesser importance. By avoiding endothelial damage it should be possible to limit the occurrence of early postoperative thrombosis and possibly severe late changes as well.

Morphologic studies in saphenous vein grafts for aorto-coronary bypass surgery. Part II: Influence of a pressure-limited graft dilation.

The evidence of considerable damage caused by stretching to the vein transplants for aorto-coronary bypasses led us to a modified technique of vein dilation that allows control and limitation of the pressure to which the veingraft is exposed. The efficiency of this procedure in terms of reduced damage to the vascular wall was investigated by microscopic and electronmicroscopic methods. It could be shown that the integrity of the intimal layer of vein grafts can be maintained to a high degree. Clinically this implies that the long-term patency rate of aorto-coronary veingrafts may be improved. This will be subject to further coronarographic studies during the follow-up of a present series of patients.

Capillarosclerosis of the lower urinary tract in analgesic (phenacetin) abuse. An electron-microscopic study.

The ultrastructural appearances in capillarosclerosis of the lower urinary tract in analgesic abuse are reported. The capillaries show thickened basement membranes consisting of numerous thin basement membrane lamellae. Between the newly formed basement membrane lamellae, masses of empty vacuoles (fat vacuoles) and a variety of membranous and vesicular structures are present. The pathogenesis of this alteration in the basement membrane is unknown. A common pathogenetic mechanism may be operative in the discoloration of renal papillae and mucous membranes of lower urinary tract on the one hand and capillarosclerosis on the other.