Hypoxic contraction of isolated canine coronary artery. Mediation by potassium-dependent exocytosis of norepinephrine

Effects of hypoxia on arterial tone, efflux of potassium, and efflux of norepinephrine were monitored for isolated canine coronary arteries labeled with radioactive potassium (42K) and norepinephrine (3HNE). Hypoxia elicited transient relaxation and subsequent sustained contraction accompanied by marked increases in the effluxes of 42K and 3HNE. After sympathetic nerve injury with 6-hydroxydopamine or cold storage, arteries responded to hypoxia with sustained relaxation. Sustained relaxation occurred also after pretreatment with L-propranolol, but not with D-propranolol or phentolamine. Inhibition of hypoxic contraction by L-propranolol did not alter 42K or 3HNE efflux. Colchicine, an inhibitor of the exocytosis of NE, suppressed hypoxic 3HNE efflux and contraction, but not 42K efflux. Proadifen inhibited 42K and 3HNE efflux as well as contraction. During proadifen-inhibited 42K efflux, exogenous K+ augmented overflow of 3HNE, indicating that proadifen relaxed the hypoxic artery primarily by inhibiting K+-dependent exocytosis of NE. The ratio of NE to dopamine beta-hydroxylase activity was similar in effluents from oxygenated arteries exposed to elevated K+ concentrations and in effluents from hypoxic arteries. Thus, hypoxia evoked exocytotic release of norepinephrine which promoted contraction by a beta-adrenergic mechanism.     

Comparison of urinary excretion of UV-absorbing constituents in healthy subjects and patients with rheumatoid arthritis using analytical isotachophoresis

Analytical isotachophoresis has been applied to the separation of urinary constituents in healthy controls and patients with rheumatoid and osteoarthritis. Various methods of comparing isotachograms have been investigated. Significant differences have been demonstrated between the pattern of UV-absorbing components in patients with rheumatoid arthritis and healthy subjects.     

Second examination in meat inspection (author's transl)

A second examination at the expense of the party adjudged to be in error is based on Section 13 of the Meat Inspection Act in the Netherlands, which has been elaborated in Sections 51 and 51a of the Meat Inspection Order. The procedure to be adopted by the second veterinary-surgeon inspector, however, has not been stipulated. The need for clear instructions is stressed. The present paper was designed to promote objectivity and uniformity in second inspections to provide legal security for the owner of the slaughtered animal as well as for the first veterinary-surgeon inspector.     

Fluoride stimulation of the rat parathyroid gland: an ultrastructural study

The parathyroid glands of rats given 150 ppm fluoride in the drinking water for 10 weeks are evaluated ultrastructurally and compared to the parathyroid glands of untreated rats. As a result of fluoride ingestion, the majority of the parathyroid cells are dark chief cells, indicating that these cells are in the active stages of the secretory cycle. More significantly, in the fluoride-treated rats, the cytoplasmic organelles of the dark chief cells are even more developed that those seen in the dark chief cells of untreated rats. The dark cells contain an electron-dense cytoplasm with abundant lamellar arrays of rough endoplasmic reticulum, spiral aggregations of free ribosomes, multiple dilated Golgi complexes, and increased numbers of secretory granules. The cells are at a minimum dimension with maximum tortuosity of the plasma membranes; and, as a result, large intercellular spaces are often seen between contiguous cells. Based on these observations, it is suggested that, in the fluoride-treated rat, a type of secondary hyperparathyroidism develops resulting in an increase in the organelles involved in protein synthesis and secretion.     

In vitro diagnosis of axillary lymph node metastases in breast cancer by spectrum analysis of radio frequency echo signals

Axillary lymph node status is of particular importance for staging and managing breast cancer. Currently, axillary lymph node dissection is performed routinely in cases of invasive breast cancer because of the lack of accurate noninvasive methods for diagnosing lymph node metastasis. We investigated the diagnostic ability of ultrasonic tissue characterization based on spectrum analysis of backscattered echo signals to detect axillary lymph node metastasis in breast cancer in vitro compared with in vitro B-mode imaging. Immediately after surgery, individual lymph nodes were isolated from axillary tissue. Each lymph node was scanned in a water bath using a 10-MHz instrument, and radio frequency data and B-mode images were acquired. Spectral parameter values were calculated, and discriminant analysis was performed to classify metastatic and nonmetastatic lymph nodes. Forty histologically characterized axillary lymph nodes were enrolled in this study, including 25 nonmetastatic and 15 metastatic lymph nodes. A significant difference existed in the spectral parameter values (slope and intercept) for metastatic and nonmetastatic lymph nodes. Spectral parameter-based discriminant function classification of metastatic vs. nonmetastatic lymph nodes provided a sensitivity of 93.3%, specificity of 92.0%, and overall accuracy of 92.5%. In comparison, B-mode ultrasound images of in vitro lymph nodes provided a sensitivity of 73.3%, specificity of 84.0%, and overall accuracy of 80.0%. Receiver operating characteristic (ROC) analysis comparing the efficacy of both methods gave an ROC curve area of 0.9888 for spectral methods, which was greater than the area of 0.8980 for B-mode ultrasound. Hence, this in vitro study suggests that the diagnostic ability of spectrum analysis may prove to be markedly superior to that of B-mode ultrasound in detecting axillary lymph node metastasis in breast cancer. Because of these encouraging results, we intend to conduct an investigation of the ability of spectral methods to classify metastatic axillary lymph nodes in vivo.