IgM rheumatoid factor (RF), IgA RF, IgE RF, and IgG RF detected by ELISA in rheumatoid arthritis

One hundred patients with rheumatoid arthritis (RA), of whom 73 were seropositive by latex or Waaler-Rose (WR) assays, or both, 100 healthy subjects, and 102 diseased controls (22 patients with systemic lupus erythematosus (SLE) and 80 with bronchial asthma) were evaluated for the presence of IgM rheumatoid factor (RF), IgA RF, IgE RF, and IgG RF by an enzyme linked immunosorbent assay (ELISA). Ninety two per cent, 65%, 68%, and 66% of the patients with RA were found to be positive for IgM, IgA, IgE, and IgG respectively. A positive correlation existed between the levels of IgM RF and IgA RF on the one hand and disease activity on the other, and the levels of IgM RF and IgA RF correlated with the levels of circulating immune complexes as measured by a C1q binding assay. The presence of extra-articular features also correlated positively with the levels of IgA RF and IgE RF. Five out of six patients with Sjögren's syndrome had very high levels of IgA RF. Of 47 patients typed for HLA-DR, DR1 and DR2 were significantly more frequent in those with the highest levels of IgM RF. Conversely, DR3 was associated with low levels or absence of IgA RF and IgE RF. These results suggest that immune response genes may regulate the level of different RF isotypes. The frequencies of IgM, IgA, IgE, and IgG RF were 59%, 36%, 9%, and 27% respectively in SLE and 25%, 2.5%, 70%, and 59% in bronchial asthma.

Pharmacokinetics of human growth hormone releasing factor (hGRF-44 NH2) in normal men after intravenous administration of a large range of doses

Three ranges of doses of growth hormone releasing factor (2.5-80 micrograms, 80-320 micrograms and 75-600 micrograms) were intravenously administered to healthy young volunteers in three double blind studies. Serum circulating GRF levels were determined by radioimmunoassay. Experimental concentration curves were fitted, using the extended least squares method, to a biexponential model for the structural model and power function for the variance model. The power variance model, compared to the constant variance model greatly reduced the coefficient of variation of the biexponential parameters. The power of the variance model was estimated to be 1.95. The distribution half-life was 6.6 min and the elimination half-life was 39.0 min (harmonic means). Total clearance was 0.12 +/- 0.01 microgram/l/min. No difference between these parameters was found for the various doses. GRF kinetics was linear established in the range 10 to 600 micrograms which means that elimination was not altered by the increased doses.

[Resectable bronchial cancer. Contribution of computed x-ray tomography in the evaluation of loco-regional extension]

A prospective study of 107 patients was performed for assessing the CT contribution in preoperative staging of lung carcinoma. Thoracotomy was performed in all patients. The results demonstrated that CT is useful in all cases when surgery is indicated. Nevertheless CT gave not benefit in cases of peripheral small tumors T1N0 classified after standard chest radiograph and fibroscopy. The statistical analysis allowed to define the most accurate size criteria to declare mediastinal nodes as hypertrophied. Furthermore this study confirms that CT criteria of mediastinal and chest wall involvement have to be very strict.

Primary lung cancer staging: prospective comparative study of MR imaging with CT

Forty-four patients with bronchogenic carcinoma were studied prospectively by both computed tomography (CT) and magnetic resonance (MR) imaging of the thorax during the week preceding thoracotomy. Transaxial MR imaging sequences included T1- and T2-weighted sequences. Coronal and sagittal T1-weighted sequences were added according to tumor location. CT and MR studies were reviewed separately, and the results were compared with surgical and pathologic findings on the basis of TNM classification. No statistically significant differences were found between the two imaging methods for the evaluation of tumor extent or node involvement. T2-weighted sequences did not yield further information on tumor extent or node involvement. Additional imaging planes (coronal or sagittal) appeared useful to study chest wall invasion. Analysis of concordances and discordances did not indicate whether one modality could be substituted for the other, or which diagnostic strategy might be more useful.

Danger of vasodilator therapy for pulmonary hypertension in patent foramen ovale

A 23-year-old woman with systemic lupus erythematosus was found to have severe pulmonary hypertension with secondary patency of the foramen ovale. Infusion of hydralazine increased the basal right-to-left shunt and resulted in a dramatic fall in arterial oxygen pressure, with subsequent irreversible cardiovascular collapse. Vasodilator therapy appears to be hazardous in patients with severe pulmonary hypertension and patent foramen ovale.

Investigation of human growth hormone releasing factor in adults

A dose-effect relationship between human growth hormone (GH) releasing factor (hGRF) and GH response was demonstrated for doses ranging from 5 micrograms per subject (minimal active dose) to 40-80 micrograms per subject (minimal dose for maximal effect). Bioactivity of GH released under hGRF was proven in the Nb2 lymphoma cell multiplication assay. Unwanted effects were observed for doses equal to or larger than 150 micrograms. Pharmacokinetic parameters were calculated from the immunoreactive GRF plasma concentrations obtained after intravenous injections of various doses. The half-lives were 6.8 +/- 0.4 min and 43.2 +/- 3 min for distribution and elimination phases, respectively. Subcutaneous administration of hGRF was shown to be effective for promoting GH release, with doses higher than those required by intravenous administration. Intermittent intravenous injection of hGRF, at 3-hour intervals, resulted in a decrease in the magnitude of GH response in normal subjects.

Hypercapnic acidosis induced by nutrition in mechanically ventilated patients: glucose versus fat

Total parenteral nutrition (TPN) increases CO2 production (VCO2) in patients on intermittent positive-pressure ventilation who cannot match their CO2 excretion to the CO2 load, leading to an increase in PaCO2. We studied gas exchange and blood gas values in six patients with chronic respiratory failure, who were ventilated at low (6 +/- .7 L/min) and high (10 +/- 2 L/min) minute ventilation during three randomized nutritional regimens: control (255 kcal/day), glucose TPN (2550 kcal/day), and lipid TPN (3000 kcal/day). At the two levels of ventilation, TPN compared to control increased VCO2 and PaCO2 (p less than .01) and decreased pH (p less than .001). At low minute ventilation, the increase in VCO2 and the hypercapnic acidosis were less with lipid than with glucose TPN (p less than .05 and p less than .01, respectively). These results indicate that the risk of TPN-induced CO2 retention is lower if minute ventilation is increased before beginning TPN. Conversely, in patients with compromised ventilatory function, this risk could be higher during intermittent mandatory ventilation or weaning from the ventilator.

Selective dietary potassium depletion and acid-base equilibrium in the rat

K+ depletion of two kinds was induced in two groups of rats by selective dietary restriction for up to 5 weeks. Complete metabolic studies for H+, K+, Na+ and Cl- were carried out daily during weeks 1, 3 and 5. In control rats of group A (receiving K+ with sodium chloride), plasma pH (7.47) and HCO3- (25 mmol/l), as well TA (titratable acid)--HCO3- and NH+4 urinary excretion rates, were stable, while balances were nil for K+ and slightly positive for Cl-. In K+-deprived rats of group A receiving sodium chloride, a progressive metabolic alkalosis developed (plasma pH reached 7.57 and HCO3- 35.8 mmol/l by 5 weeks), and TA--HCO3- and NH+4 urinary excretion rates were not different from controls. Plasma K+ fell progressively from 4.20 to 2.20 mmol/l, with negative K+ balance. Balances for Na+ and H2O were highly positive and plasma renin activity and aldosterone decreased by week 5. Hypochloraemia developed with positive Cl- balance. In control rats of group B (receiving K+ with neutral sodium phosphate), a slight metabolic alkalosis developed, and TA--HCO3- excretion rate was increased compared with control rats of group A.(ABSTRACT TRUNCATED AT 250 WORDS)

Ventilatory adaptation to metabolic alkalosis in adult awake potassium restricted rats

The resting ventilation of awake rats, developing metabolic alkalosis as a result of sustained dietary potassium (K) restriction, was compared to that of age-matched controls. Extending the measurements over 17 weeks and using adult rats indicated, as soon as the third week, a significant progressive fall in the minute ventilation of low K rats, which previous studies limited to a single time determination did not consistently ascertain. The ventilatory adaptation observed in all groups, as well as the superimposed respiratory compensation to metabolic alkalosis in low K rats, resulted only from frequency changes. In both groups, the duration of inspiration was inversely correlated with the age of the animals. The duration of expiration was stable in controls but increased significantly with time in low K rats. According to these data, the respiratory compensation to K-depletion alkalosis in the rat is achieved only through an adjustment in the timing component of the control of breathing.