Effect of estrogen on calcium homeostasis and pituitary hormones in the growing chick

An experiment was carried out to investigate the effect of a range of estradiol (E2) doses (0.1-6.5 micrograms/g body wt/day) on vitamin D metabolism and the plasma levels of growth hormone (GH) and prolactin (PRL) in the growing chick. Doses of 0.5-0.7 microgram/g E2, which are insufficient to raise the plasma calcium level, did induce an increase in growth rate, an increase in 25-hydroxyvitamin D 1 alpha-hydroxylase (1-hydroxylase) and 24-hydroxylase activities, and an increase in plasma GH level. These parameters leveled off or fell over the dose range 1-2 micrograms/g E2 but there was evidence of a second peak in 1-hydroxylase activity at 6 micrograms/g E2. At this high dose rate, the plasma Ca level rose to 8 mM, as it does in the laying hen; 24-hydroxylase activity, growth rate, and plasma GH and plasma PRL levels all decreased. It was concluded that the dose response to estrogen in the growing chick is not linear and, in the case of 1-hydroxylase activity, may even be biphasic.     

The complex nature of the mechanism of toxicity of antibiotic dithiacyclohexadiene polyines (thiarubrines) from the asteraceae

Thiarubrine A, a dithiacyclohexadiene polyine from the roots of Chaenactis douglasii, and a related dithiacyclohexadiene from Rudbeckia hirta exhibit strong light-independent antibacterial and antifungal activity. This activity is enhanced by exposure to visible light. Visible light also converts the compounds to the corresponding thiophenes. These are antibiotic only when irradiated with UV-A. Dithiacyclohexadienes are the first polyines to exhibit such complex mechanisms of toxicity towards microorganisms.     

Fricke supraorbital flap for reconstruction of total lower eyelid defects

Summary Split or full thickness eyelid defects resulting from tumor destruction or surgical excision present a dilemma for plastic and reconstructive surgeons. Full thickness eyelid replacement requires composite grafting of the skin, together with tarsal support of its substitute and mucosa. The flap described by Fricke in 1829 was used for reconstruction of anterior lamella in six lower eyelid defects. In three of our cases chondromucosal grafts taken from nasal septum were utilized for posterior lamella repair. The results have been satisfactory from a functional and cosmetic standpoint.     

Sodium reabsorption by the Henle loop in humans

In a previous study, we described a new method [3] to measure Na reabsorption by each segment of the human nephron independently. Reabsorption was expressed as equivalent volumes of solute-free water (CH2O) generated by the loop of Henle (CH2O-HL) and by the distal tubule (CH2O-DT), and dissipated by back diffusion (BD) across collecting ducts (CH2O-BD). These data were obtained during maximal water diuresis (MWD). The present study was undertaken to calculate CH2O-HL by experiments performed during maximal antidiuresis (MA). For this purpose, a new theoretical approach was devised, described by algebraic equations which allowed calculations of segmental transport during MA alone, where only CH2O-HL could be calculated independently. The study was performed on 14 normal volunteers who were studied twice by clearance measurements, firstly during MWD and again during MA. In each experiment, clearance periods were performed during baseline conditions and during the administration of furosemide (0.7 mg/kg bolus injection followed by 0.06 mg/kg/min maintenance infusion). From the values measured during either condition, segmental reabsorption was calculated. During MWD, CH2O-HL averaged 19.4 + 10.4, during MA 20.4 + 8.0 ml/min/GFR X 100; p greater than 0.05. The paired measurements were significantly correlated (r = 0.80; p less than 0.01). These data demonstrate that CH2O-HL obtained with the original theory is a reproducible result that can be confirmed with independent measurements obtained during different experimental conditions. Thus, measurements of segmental Na transport in the human nephron are feasible and can contribute important informations on disease states.     

Uptake of iodine-123 MIBG by pheochromocytomas, paragangliomas, and neuroblastomas: a histopathological comparison

The percentage uptake of [123I]metaiodobenzylguanidine (MIBG) by tumors of the paraganglion system is compared with the number of neurosecretory granules (assessed by both light and electron microscopy) in the subsequently resected tumors in six patients. Iodine-123 MIBG was injected intravenously; the tumor uptake of [123I]MIBG varied between 0.001% and 0.14% of the injected dose per gram of tumor tissue at 22 hr. The number of neurosecretory granules in tissue sections was scored on a scale of I-III. A direct proportional correlation was found between the percentage uptake of [123I]MIBG by the tumor and the number of neurosecretory granules in the tissue sections but not with plasma or urinary catecholamines. This technique for imaging reflects the storage status of the tumor better than plasma and urinary catecholamine measurements.     

Neuroblastoma: the role of MR imaging

Thirty-five MR examinations were performed in 17 children with neuroblastoma during the course of their diagnostic evaluation and treatment. Findings were confirmed by correlation with the results of other imaging techniques, biopsies, and surgical and autopsy findings. MR accurately detected the lesions and their extent in all patients. It correctly evaluated the possibility of resectability and showed metastases, response to treatment and development of complications. MR appears to be a reliable technique for the diagnosis, staging, and follow-up of children with neuroblastoma.     

Abnormal nephrogram pattern as an adverse reaction to contrast material. Case report

Up to now two abnormal nephrographic patterns have been described as a result of arterial hypotension as an adverse response to urographic contrast material. We would like to describe a third pattern.