Jejunal schwannoma in neurofibromatosis: an unusual cause of massive gastrointestinal bleeding.

Small intestinal schwannomas are exceedingly rare tumors arising mainly from Schwann cells of Auerbach's plexus, and are usually solitary and asymptomatic. We report the first case of a jejunal schwannoma causing life-threatening gastrointestinal bleeding in a patient with neurofibromatosis.

Measuring prices of Medicare physician services.

This study develops two sets of price indices for Medicare physician services. The first measures price changes, and the second measures geographic price differentials. The indices can be used to adjust Medicare physician spending data to examine growth or variations in the volume and intensity of services. In both instances, it is necessary to apply an index form that reflects both the rapid changes and variability in the mix of physician services received by Medicare beneficiaries and their relative importance. This suggests that an index based on a fixed basket of services (e.g., a Laspeyres index) can produce a biased measure of price. An alternative methodology based on the Fisher's Ideal Index form was used. This index allows service weights to vary over time and across areas. In the case of price change, the index is "chained" to acknowledge the introduction of new services over several years. It is concluded that the Fisher's Ideal approach is essential for cross-sectional price comparisons, in light of the high variability in service mix across areas. In measuring price changes, it was found that "chaining" was more important empirically than allowing the relative importance of services to change between years. During the 1985-1989 study period, Medicare payment rates grew, on average, by 3.5% annually. This rate varied across both time and types of services as a result of differential fee updates and explicit pricing policies implemented by Medicare (e.g., reductions in payments for "overvalued" procedures). Cross-sectionally, our results show that 1988 fees in the highest-priced areas were more than 1.5 times those in the lowest-priced areas.

Influence of body position on pressure and airflow generation during hypoxia and hypercapnia in man.

1. Inspiratory oesophageal pressure and ventilatory responses to hyperoxic, progressive hypercapnic rebreathing (HCVR) and isocapnic, progressive hypoxic rebreathing (HVR) were studied in five normal males in both supine and upright seated positions. 2. No significant differences were found in the ventilatory response to hypercapnia between the supine and upright position. The slopes of the relationship between minute ventilation (VI) and the increase of end tidal PCO2 (delta P(ET), CO2) were 3.27 +/- 0.23 and 2.76 +/- 0.24 1 min-1 mmHg-1 supine and upright, respectively. However, the change in oesophageal pressure from the end expiratory level observed during quiet breathing to that at peak inspiration (delta P(oes), I) in relationship to delta P(ET),CO2 was greater supine than upright (1.23 +/- 0.07 versus 0.79 +/- 0.11 cmH2O mmHg-1, P < 0.01). 3. In contrast, during hypoxia-stimulated breathing the slope of the minute ventilation versus oxyhaemoglobin saturation curve (VI-Sa,O2) was flatter supine than upright (1.00 +/- 0.03 versus 1.75 +/- 0.05 l min-1 (percentage fall in Sa,O2)-1, P < 0.0001), but delta P(oes), I in relation to Sa,O2 during hypoxic rebreathing was similar supine and upright (0.38 +/- 0.03 versus 0.40 +/- 0.04 cmH2O (percentage fall in Sa,O2)-1, respectively. 4. It is concluded that body position does not affect the ventilatory response to progressive hyperoxic hypercapnia but does affect the relationship between delta P(oes), I and delta P(ET),CO2. In contrast, body position affects the ventilatory response to isocapnic progressive hypoxia, but does not affect the relationship between delta P(oes), I and Sa,O2.

Chemical and postural influence on scalene and diaphragmatic activation in humans.

The electromyographic activity of the diaphragm (EMGdi) and scalene muscle (EMGsc) was studied in the supine and upright positions, respectively, during hyperoxic progressive hypercapnic rebreathing (HCVR) in five healthy males. End-expiratory esophageal pressure (EEPes) was quantified on a breath-to-breath basis as a reflection of altered end-expiratory lung volume. There was no significant difference in the slopes of EMGdi, expressed as a percentage of maximum at total lung capacity vs. minute volume of ventilation (VI), between the supine and upright positions [0.79 +/- 0.05 (SE) vs. 0.92 +/- 0.17, respectively]. In contrast, the slope of the regression line relating EMGsc to VI was steeper in the upright than in the supine position (0.69 +/- 0.05 vs. 0.35 +/- 0.04, respectively; P less than 0.005). Positive EEPes at comparable VI at the ends of HCVRs were of greater magnitude upright than supine (3.27 +/- 0.68 vs. 4.35 +/- 0.60 cmH2O, respectively, P less than 0.001). We conclude that altering posture has a greater effect on scalene and expiratory muscle activity than on diaphragmatic activity during hypercapnic stimulation.

Nuclear binding of the estrogen receptor: a potential predictor for hormone response in metastatic breast cancer.

We have previously described an in vitro immunohistochemical test employing anti-receptor antibodies, for demonstrating the nuclear binding characteristics of estrogen receptors (ER) in breast carcinomas. Based on a retrospective analysis of twenty-five patients with estrogen receptor-positive (ER+) breast cancer who were treated with hormone therapy and whose clinical responses were evaluable, we were able to demonstrate that this test may be valuable to predict which, among the ER+ tumors (whether or not they are progesterone receptor positive, PR+), are likely to respond to hormone therapy and which may fail. While tumors in which ER exhibited abnormalities in nuclear binding behavior (ligand-independent nuclear binding or no nuclear binding) failed hormone therapy (16 out of 19 patients), those in which nuclear binding of ER appeared normal (ligand-dependent) in the in vitro test, responded to hormone therapy (5/6 patients). While our previous report dealt with the procedural details, specificity of the reagents, and the design of the study, this report addresses the clinical aspects of this study and response correlation.

Sleep apnea in patients with left ventricular dysfunction: beneficial effects of nasal CPAP.

Five patients with congestive heart failure (CHF) and 1 with left ventricular dysfunction but without CHF were found to have sleep apnea. Central sleep apnea (CSA) related to Cheyne-Stokes respiration was seen in 4 cases while obstructive sleep apnea (OSA) was seen in 2. All patients had symptoms of sleep apnea. Nasal continuous positive airway pressure (NCPAP) was effective in reversing CSA and OSA in all patients with improvement in sleep structure and alleviation of symptoms of sleep apnea. In addition, all experienced a reduction in cardiac dyspnea. This was associated with a 5% or greater increase in left ventricular ejection fraction while on NCPAP, compared to baseline value off NCPAP in 5 patients and resolution of chronic pleural effusion and pulmonary edema in the sixth. We conclude that Cheyne-Stokes respiration during sleep may give rise to a CSA syndrome that is reversible by NCPAP. In addition, NCPAP therapy may lead to a reduction in cardiac dyspnea and improvement in left ventricular function in patients with left ventricular dysfunction and sleep apnea.

Effect of nasal continuous positive airway pressure on sleep apnea in congestive heart failure.

We studied five patients with chronic stable congestive heart failure (CHF), all of whom demonstrated recurrent apneas in association with Cheyne-Stokes respiration (CSR) during sleep. All five patients had symptoms consistent with a sleep apnea syndrome. Nasal continuous positive airway pressure (NCPAP) was administered at 8 to 12.5 cm H2O to all patients during sleep. The number of apneas fell from (mean +/- SE) 60 +/- 12/h of sleep on the control night to 9 +/- 7/h of sleep (p less than 0.01) on the NCPAP night, whereas mean nocturnal SaO2 rose from 88 +/- 2% on the control night to 92 +/- 2% (p less than 0.025) while on NCPAP. This was associated with resolution of symptoms of sleep apnea. In addition, resting left ventricular ejection fraction (LVEF) as measured by radionuclide angiography (RNA) rose from 31 +/- 8% while off NCPAP to 38 +/- 10% (p less than 0.05) while on NCPAP. Furthermore, all five patients experienced marked improvement in symptoms of heart failure from functional classes III and IV (New York Heart Association Classification) prior to NCPAP therapy to class II after NCPAP therapy was instituted. We conclude that, in certain patients, CSR during sleep associated with chronic CHF constitutes a sleep apnea syndrome, which can be alleviated by NCPAP. In addition, NCPAP therapy may lead to a reduction in cardiac dyspnea and improvement in left ventricular function.