Distinct vasopressin content in the hypothalamic supraoptic and paraventricular nucleus of rats exposed to low and high ambient temperature.

Both high and low ambient temperature represent thermal stressors that, among other physiological responses, induce activation of the hypothalamic-pituitary-adrenal (HPA) axis and secretion of arginine-vasopressin (AVP). The exposure to heat also leads to disturbance of osmotic homeostasis. Since AVP, in addition to its well-known peripheral effects, has long been recognized as a hormone involved in the modulation of HPA axis activity, the aim of the present study was to elucidate the hypothalamic AVP amount in the acutely heat/cold exposed rats. Rats were exposed to high (+38°C) or low (+4°C) ambient temperature for 60min. Western blot was employed for determining hypothalamic AVP levels, and the difference in its content between supraoptic (SON) and paraventricular nucleus (PVN) was detected using immunohistochemical analysis. The results showed that exposure to both high and low ambient temperature increased hypothalamic AVP levels, although the increment was higher under heat conditions. On the other hand, patterns of AVP level changes in PVN and SON were stressor-specific, given that exposure to cold increased the AVP level in both nuclei, while heat exposure affected the PVN AVP content alone. In conclusion, our results revealed that cold and heat stress influence hypothalamic AVP amount with different intensity. Moreover, different pattern of AVP amount changes in the PVN and SON indicates a role of this hormone not only in response to heat as an osmotic/physical threat, but to the non-osmotic stressors as well.

Distinct and combined effects of acute immobilization and chronic isolation stress on MAO activity and antioxidative protection in the heart of normotensive and spontaneously hypertensive rats.

The heart is an organ especially sensitive to the sympathetic overstimulation and therefore to the influence of stressors and hypertension. The aim of the present study was to investigate the effect of two distinct types of stressors, acute immobilization (2 h) and chronic isolation stress (21 days), as well as their combined effect on the activity of monoamine oxidase (MAO), superoxide dismutase, catalase (CAT) and the ascorbic acid (AA) content in the heart of normotensive and spontaneously hypertensive rats (SHR). The results obtained show that in basal conditions heart MAO and CAT activity (p < 0.05), as well as AA concentration (p < 0.01) were higher in SHR than in normotensive ones. The acute immobilization significantly decreased heart MAO activity in both examined strains (p < 0.01). On the other hand, chronic isolation, separately or in combination with immobilization, did not affect this enzyme, in the heart of either hypertensive or normotensive rats, which was associated with the reduced antioxidative protection (p < 0.01, p < 0.05).

Ultrasonic specimen radiography for non-palpable breast lesions.

A retrospective review of ultrasound guided breast excisional biopsies performed in a Surgical Unit of Princess Alexandra Hospital in 1998-99 was undertaken to assess the use of ultrasound specimen radiography. In this series a total of 55 localization biopsies were performed for impalpable lesions in 53 women. In 21 patients (38%), specimen ultrasound was used to confirm that the lesion in question had been excised, whereas for 34 lesions (62%), specimen X-ray was undertaken. In a total of six cases (10.9% overall) the radiographic abnormality was seen on ultrasound only. Real-time specimen sonography is a technique which is very appropriately utilized in conjunction with ultrasound guided excisions and can be easily performed either in the radiology department or the operative suite with minimal time delay. It could have particular application for lesions that are detected in younger women with dense breast parenchyma. The results of this review confirm specimen sonography to be a reliable technique.

Time-dependent effects of starvation on serum, pituitary and hypothalamic leptin levels in rats.

Leptin is produced by white adipose tissue and other cell types and is involved in both short- and long-term appetite control. Here we studied effects of starvation on serum, pituitary and hypothalamic levels of leptin during 72 h period. Each of the starved groups was sacrificed simultaneously with the group of ad libitum fed animals. The progression of the discrete starvation response phases was monitored by testing the blood glucose, free fatty acid, urea and corticosterone levels. Starvation caused biphasic increase in corticosterone and free fatty acid levels, and significant but transient decrease in urea and glucose levels. Starvation also abolished diurnal rhythm of changes in leptin concentrations in serum and hypothalamic and pituitary tissues. Only 6 h starving period was sufficient to lock serum leptin at low levels, whereas 12 h were needed to silence leptin production/secretion in hypothalamus for the whole examined period. In contrast, leptin production by pituitary tissues of starved animals required 24 h to reach minimum, followed by full recovery by the end of starvation period. These results indicate the tissue specific pattern of leptin release and suggest that the locally produced leptin could activate its receptor in pituitary cells independently of serum levels of this hormone.

Excision biopsy findings of patients with breast needle core biopsies reported as suspicious of malignancy (B4) or lesion of uncertain malignant potential (B3).

AIMS: The UK National Health Service Breast Screening Programme has proposed five categories for reporting breast needle core biopsies. The majority of cores are reported as benign (B1), normal (B2) or malignant (B5). The predictive value of the two borderline categories suspicious of malignancy (B4) and lesion of uncertain malignant potential (B3) was studied. METHODS AND RESULTS: Over a 2-year period a total of 3822 breast needle core biopsies were performed, with 2997 from symptomatic patients and 825 from women undergoing mammographic screening, including 43 B4 reports (40 patients) and 120 B3 reports (116 lesions in 115 patients). The frequencies of B4 (2.5% versus 0.7%) and B3 cores (7.3% versus 2.0%) were both higher in screening than in symptomatic patients. B4 was most commonly used for small fragments of atypical cells separate from the main core or focal atypical intraductal proliferations. The criteria for calling a core B3 were: atypical intraductal epithelial proliferations (including foci that in excision specimens would be classified as atypical ductal hyperplasia), lobular neoplasia, radial scar, papillary lesion, fibroepithelial lesion with cellular stroma and spindle cell proliferations. Excision biopsies were performed in 39 patients with B4 core and 96 with B3 core. Invasive carcinoma or ductal carcinoma in situ was seen in 33 of the patients with B4 (85%) and in 29 of those with B3 cores (25%). Some categories of B3 core were associated with a higher rate of malignancy (40% for atypical intraductal epithelial proliferations and 46% for lobular neoplasia). CONCLUSIONS: The positive predictive value for carcinoma is high following a B4 core (86%). The lesion should be excised, but definitive cancer treatment is not appropriate. In some cases a definite diagnosis of malignancy can be made on repeat core. The B3 group is more heterogeneous and has a lower rate of malignancy on further biopsy (25%). The majority of B3 lesions require excision. All these patients should be discussed at multidisciplinary meetings.