Refractory hypothalamic alpha-mSH satiety and AGRP feeding systems in rats bearing MCA sarcomas

In pre-anorectic tumor-bearing (TB: methylcholanthrene-induced sarcoma) rats, injection of alpha-melanocyte stimulating hormone (alpha-MSH) into the perifornical hypothalamus (PFH) had no significant effect on food intake at a dose (5 microg) that reduced feeding in non-TB control rats. Following the development of anorexia, injection of alpha-MSH MC3/MC4 receptor antagonists, SHU9119 (1 microg) or 4 microg agouti-related protein (AGRP), stimulated feeding in non-TB rats, while having no significant effect in TB rats. Concentrations of alpha-MSH were not altered significantly in ventromedial, dorsomedial or lateral hypothalamic areas of TB rats, and proopiomelanocortin (POMC) messenger RNA was not changed in TB rats in these hypothalamic areas. Determination of cytokines by ELISA in non-operated TB and non-TB rats revealed elevated IL-2 in plasma and hypothalamus as well as increased TNF-alpha in the hypothalamus of anorectic TB rats. IL-1B was not detectable in plasma and was not altered significantly in hypothalamus of TB rats. These results suggest that the POMC alpha-MSH satiety system is refractory in TB rats, even prior to the onset of anorexia. This change in MC3/MC4 receptor response does not appear to be secondary to alterations of endogenous alpha-MSH in TB rats. Cytokine involvement in the altered response to MC3/MC4 receptor stimulation and blockade is a possibility, since TNF-alpha and IL-2 were increased in hypothalamus of anorectic TB rats. Therefore, these results suggest major alterations in POMC neuropeptide systems in TB rats as anorexia progresses. Although these changes do not appear to have occurred due to grossly-altered concentrations of alpha-MSH, elevated cytokine activity in the hypothalamus may be an important factor. Due to the complex multi-factorial nature of feeding control, additional factors are likely to be involved in cancer anorexia.     

Wie sich Oasen‐Bananen gegen ihre Feinde wehren. Uralter Toleranzmechanismus im Oman entdeckt

Until recently little was known about the crop diversity in the Sultanate of Oman, situated at the NE tip of the Arabian Peninsula. Interdisciplinary research in the often millenia‐old oases provide evidence for their role as reservoirs for plant genetic resources of ancient varieties of wheat and banana. Two newly discovered banana clones show a highly efficient biochemical defense mechanisms against some of the most devastating pests and diseases of banana. If these mechanisms can be properly understood and exploited in breeding programs, may have major impact on the commercial production of edible banana.     

Minimizing tissue-material interaction in microsensor for subcutaneous glucose monitoring

A new implantable electrocatalytic glucose sensor for subcutaneous glucose monitoring has been fabricated by immobilizing glucose oxidase on a chemically modified carbon fiber. The sensor was inserted subcutaneously on a male spraguely rat without any incision after dipping the microsensor in the rat's serum for 3 days. The so called "stained" microsensor, operated in the amperometric mode with an applied potential of +0.23 V versus Ag|AgCl, was able to directly measure the glucose concentration upon infusion of glucose. The results obtained were encouraging, with the response time was less than 2s and the apparent Michaelis-Menten value at 5.1+/-0.5mM. The "stained" microsensor shows good stability and reproducibility with constant response spanned over 25 days. Most common interferences in glucose analysis were minimized by the outerlayer Nafion. Hematology examinations showed minimal material-tissue interaction. Use of such mechanical devices will allow a more refined understanding towards glucose control in diabetic patients as the implanted microsensor was not effected by biocompatibility failures.     

Characteristics of Biocalcium Powders from Pre-Cooked Tongol (<Emphasis Type="Italic">Thunnus tonggol</Emphasis>) and Yellowfin (<Emphasis Type="Italic">Thunnus albacores</Emphasis>) Tuna Bones

Characteristics of biocalcium powder from pre-cooked tongol tuna bone (BTG) and yellowfin tuna bone (BYF) were investigated, in comparison with their calcined bone powder named CTG and CYF, respectively. Average calcium (40.3%) and phosphorus (19.19%) contents of CTG and CYF were higher than those of BTG and BYF (Ca: 26.74%, P: 12.72%). Nevertheless, similar mole Ca/P ratio (1.62–1.63) was observed among all samples. Mean particle size of all samples was approximately 14 μm. Both CTG and CYF powders exhibited the interconnected granular structure. BTG had higher b*- value than BYF (p < 0.05). Generally, CTG and CYF had lower b*-values with slightly higher L*-values than both BTG and BYF (p < 0.05). X-ray diffraction results indicated the presence of hydroxyapatite in all samples, in which their crystallinities were increased from 54% to 90% after calcination. Hydroxyproline and protein were detected in both biocalcium powders, but were not detectable in calcined bone powders. The abundance of volatile compounds was noticeably lower in BYF, compared to BTG. Negligible volatiles were detected in both calcined bone powders. Based on a simulated gastrointestinal tract study, both BTG and BYF had higher soluble calcium content than calcium carbonate and their corresponding calcined bone powders, indicating the higher availability for absorption.