Compensatory mechanisms induced by high oropharyngeal airway resistance in rats.

Acid base balance changes were observed during 72 h following bilateral nasal obstruction in rats. Mouth breathing caused acute respiratory acidosis and marked aerophagia, leading to spontaneous death of the experimental animal 80 to 90 h postoperatively. Stenotic oropharyngeal airway, due to palatal-epiglottic approximation, is supposed to be responsible for respiratory insufficiency in the nose obstructed rats. The compensatory changes in respiratory mechanics caused by high oropharyngeal airway resistance, together with some possible reflex changes, may have caused either air swallowing or aspiration. As changes in acid base balance parameters did not show breakdown of the compensatory mechanisms during the first 72 h postoperatively, it is supposed that the increased air volume in stomach and guts, causing elevation of the diaphragm and paralytic ileus, contributed to the experimental animals' death.

Adaptation to oral breathing after anterior nasal packing.

We report the changes in blood gas tensions in a group of 17 patients during a five-day period of anterior nasal packing after endonasal surgery. Significant hypocapnia was observed in the early postoperative period, which was followed by significant hypoxemia within the first 48 h after surgery, and also shortly after removal of the nasal pack. Analyses of the changes in blood gas tensions suggested disturbances in the ventilation-perfusion ratio. Most subjects required a period of 48 h to adapt to oral breathing.

Antineutrophil cytoplasmic autoantibodies-antigen specificity and associated diseases.

Antineutrophil cytoplasmic antibodies (ANCA) are widely used as a useful diagnostic marker for small vessel vasculitides, although the test may occasionally be positive in various other conditions. The aim of this study was to assess ANCA in various clinical-pathological settings. ANCA were tested by indirect immunofluorescence and enzyme-linked immunosorbent assay and were found to be positive in 423 patients in the period from 1989-1999. Patients were grouped in accordance with their clinical-pathological setting as follows: 1. pauci-immune vasculitis confirmed by biopsy (n = 151), 2. clinically suspected vasculitis (n = 59), 3. inflammatory bowel diseases and autoimmune hepato-biliary disorders (n = 83), and 4. miscellaneous diseases (n = 130). The association of proteinase 3 ANCA with Wegener's granulomatosis (45/56) and myeloperoxidase ANCA with microscopic polyangiltis (45/54) and pauci-immune necrotising glomerulonephritis (24/28) was established. However, ANCA with other specificities were also shown to be present in these forms of vasculitides. ANCA, specific mostly for myeloperoxidase but also for other or unknown ANCA antigens, frequently revealing atypical immunofluorescence patterns, were characteristically found in other diseases. The titres of ANCA were significantly higher (p < 0.05) in patients with pauci-immune vasculitis than in those with clinically suspected vasculitis and other diseases. In conclusion, well standardised techniques for ANCA testing in conjunction with the clinical picture and histopathologic findings, if available, may significantly contribute to the diagnosis of small vessel vasculitides.

Cytoplasmic steroid receptors in cancer of the larynx.

There are many data that suggest that the larynx is a target organ for steroid hormones, especially androgens. Since laryngeal cancers occur much more often in males, it is conceivable that androgens might be the growth-stimulating factor for such tumors. In order to test this concept further, neoplastic tissues from 68 patients (64 males, 4 females) were obtained during planned total laryngectomies and were tested for the presence of androgen (AR) and estrogen (ER) receptors. In 18 cases progesterone receptors (PgR) were also quantified. The dextran-coated charcoal technique was used to determine hormone receptors and the number of the binding sites and the equilibrium constant of dissociation were calculated according to Scatchard. 3H-R1881 was used as the ligand for the measurement of AR, 3H-estradiol for ER, and 3H-R5020 for PgR. AR was present in 11 tumor specimens (1 female, 10 males) and the concentration varied from 2.8 to 17.1 fmol/mg proteins. ER were found in 6 tumors (1 female, 5 males) in concentrations of 2.9-11.2 fmol/mg proteins. Three tumor specimens contained both AR and ER. All tumors analyzed lacked PgR. These results suggest that at least some laryngeal carcinomas might be hormone dependent, indicating that certain patients could benefit from antiandrogen therapy.

Relationship between T4, T3 and T4/T3 ratio in thyroid tissue, thyroid and peripheral veins in patients with nontoxic nodular goiter.

The relationship between T4, T3 and T4/T3 ratio in thyroid nodules/paranodular tissues, thyroid and peripheral veins has been investigated in 26 patients with nontoxic nodular goiters; eleven of them were treated with l-thyroxine 150 micrograms daily. A significant correlation between iodothyronine concentrations and T4/T3 [corrected] ratio in paranodular thyroid tissues and thyroid effluents was found in both groups of patients. By contrast, the correlation between these parameters in the nodule and thyroid veins was poor, which implies that the thyroid hormone pattern in the thyroid veins on the side of nodular lesion is predominantly controlled by the release of the hormones from paranodular healthy tissue. A close dependence of the serum T4/T3 ratio on the values of iodothyronines and their ratio in thyroid tissues and thyroid veins was observed in nontreated, but not in treated patients. Conversely, in the latter group, the thyroidal T4/T3 ratio in paranodular tissue, but not in the nodule, was found to be dependent on the serum T4/T3 ratio, suggesting that paranodular thyroid tissue more readily responds to 1-thyroxine-inhibited TSH secretion. The results demonstrate that 1. the serum thyroid hormone pattern under physiological conditions is dependent on the intrathyroidal T4/T3 ratio, and 2. minor alterations in the serum thyroid hormones may secondarily change the thyroidal T4/T3 ratio, presumably by their effect on TSH secretion.

Exogenous and endogenous suppression of thyroid-stimulating hormone induces similar effects on thyroidal iodothyronines.

Thyroidal concentrations of T4 and T3 and the T4/T3 ratio were analyzed in the nodular and paranodular tissues from two groups of patients with suppressed TSH secretion. The first group consisted of 17 patients with nontoxic nodular goitre (NG), 8 of whom received long-term levothyroxine therapy to suppress TSH, while remaining 9 were untreated. The second group consisted of 10 patients with autonomously functioning thyroid adenoma (AFTA), in whom TSH secretion was suppressed due to the adenoma-induced increase in thyroid hormone concentrations. In nodular tissues of NG patients, thyroidal T4 and the T4/T3 ratio were significantly higher in treated than in untreated patients (0.34 +/- 0.05 vs. 0.15 +/- 0.02 mol T4/mol of thyroglobulin (Tg) and 10.9 +/- 1.2 vs. 5.2 +/- 0.7 respectively). Analysis of paranodular tissues of NG patients also revealed a higher T4/T3 ratio in treated patients (16.0 +/- 2.1 vs. 6.9 +/- 0.9), although thyroidal T3 and T4 concentrations in treated and untreated patients were similar. In AFTA patients, both T3 and T4 concentrations were higher in the adenoma than in paranodular tissues (0.14 +/- 0.04 vs. 0.02 +/- 0.005 mol T3/mol Tg and 1.08 +/- 0.32 vs. 0.26 +/- 0.06 mol T4/mol Tg), whereas the T4/T3 ratio was significantly higher in paranodular tissues (23.2 +/- 5.9 vs. 9.3 +/- 1.8). These results indicate that suppression of TSH induced either exogenously or endogenously results in an increase in the thyroidal T4/T3 ratio that reflects an increase in T4 and/or a decrease in T3 concentrations. These findings also support the notion that TSH preferentially stimulates thyroidal T3 production.

Increased thyroidal T4/T3 ratio in nodular and paranodular tissues of nontoxic goiter following suppressive treatment with thyroid hormones.

The effect of suppressive treatment with thyroid hormones on thyroidal iodothyronines and T4/T3 ratio in nodular and paranodular tissues was investigated in 12 patients with nontoxic goiter. Results were compared to those from 11 nontreated patients. Continuous thyroid hormone administration produced a significant increase in thyroidal T4 and T4/T3 ratio in nodular tissues while T3 remained unchanged. In paranodular tissues a significant rise of T4/T3 ratio, an insignificant increase in T4 and a decrease in T3 were observed following the administration of thyroid hormones. The results are very similar to those obtained in paranodular tissue of autonomously functioning thyroid nodule, and are probably the consequence of suppressed TSH secretion, as TSH predominantly stimulates the synthesis of T3 and/or thyroidal T4 monodeiodination.

Thyroidal thyroxine and triiodothyronine in autonomously functioning thyroid nodule and paranodular tissue.

Thyroidal thyroxine (T4), triiodothyronine (T3), thyroglobulin (Tg) and T4/T3 ratio were investigated in nodular and paranodular tissue from 16 patients with autonomously functioning thyroid adenomas. The concentration of T4 and T3 in the nodule were 97.7 +/- 20.5 (Mean +/- SE) and 10.2 +/- 2.4 micrograms/g wet weight (w.w.). Both iodothyronines were significantly lower in paranodular tissue (22.6 +/- 4.8 and 1.45 +/- 0.32 micrograms/g w.w., respectively), but with disproportionately decreased T3 which resulted in T4/T3 ratio (25.4 +/- 6.4) higher than in adenoma tissue (11.2 +/- 1.6). In patients with high normal or supranormal serum T3 concentration, thyroidal concentration of T3 in adenoma tissue was higher (15.6 +/- 5.0 vs. 6.3 +/- 1.2 micrograms/g w.w.) and T4/T3 ratio lower (8.05 +/- 2.1 vs. 13.2 +/- 1.9) than in patients with normal serum T3. The results suggest that thyroid release of T3 from adenoma is relatively higher than T4 in patients with autonomously functioning thyroid nodules and increased peripheral T3.