The effect of 5-hydroxytryptamine (5-HT) on the crypt cell production rate in normal human duodenal mucosa cultured in vitro was studied using a stathmokinetic technique with crypt microdissection. The addition of 5-HT (2 mg/ml) to the culture medium significantly increased the crypt cell production rate (p < 000 1), suggesting that this amine may have a trophic effect on crypt cells in vitro. ...

www.sciencemag.org SCIENCE VOL 323 27 MARCH 2009 1641 COVER False-color, aberration-corrected transmission electron microscope image of a suspended single atomic layer of graphene. When an electron beam induces ejection of an atom from the edge of an intentionally made ~3-nm hole (black), the hole enlarges; the remaining edge carbon atoms rearrange from perfect hexagons into predicted metastabl...

Nearly 25 years ago, Allan Wilson and colleagues isolated DNA sequences from museum specimens of kangaroo rats (Dipodomys panamintinus) and compared these sequences with those from freshly collected animals (Thomas et al. 1990). The museum specimens had been collected up to 78 years earlier, so the two samples provided a direct temporal comparison of patterns of genetic variation. This was not ...

1. This report has been prepared by the Secretariat using information provided by the Parties in response to Notifications to the Parties and complementary research conducted by the Secretariat itself. It aims to assist Parties in making progress in the implementation of Resolution Conf. 10.8, Decision 10.44 and Decision 10.65. The Secretariat wishes to express its appreciation to those Parties...

Since alcohol is a general central nervous system depressant, it affects the motor and cognitive performance. Alcohol abuse is a major cause of medical and social problems. Additionally, to determine cause of death in legal medicine centers, alcohol analysis is the most frequently performed test in forensic toxicology laboratories. Accurate interpretation of ethanol concentration at the time...

Fixation is usually the first step to prepare biological specimens for microscopy. Any treatment which will preserve cell structure and its biochemical composition can be deemed to be fixation. Of course, the quality of fixation is the key for all following steps which are necessary in histological research. Hence, preservation of cells with minimal alteration of morphology and virtually no los...

A technique for the extraction of cells from bone marrow trephine core biopsy specimens using collagenase digestion was assessed in 39 cases (33 diagnostic and six normal). Diagnostically useful numbers of cells were extracted from all marrows. Morphological assessment ofcytocentrifuge preparations of these cells gave a correct diagnosis in 23 (60%) of cases compared with 27 (70%) for the corre...

The effects of sodium butyrate and sodium bromo-octanoate (an inhibitor of P oxidation) on colonic mucus glycoprotein (mucin) synthesis have been assessed using tissue from colonic resection samples. Epithelial biopsy specimens were incubated for 16 hours in RPMI 1640 with glutamine, supplemented with 10% fetal calf serum and N-acetyl-[3H]glucosamine (3H]-Glc NAc), and differing concentrations ...

Fifty jejunal biopsy specimens obtained from normal subjects and from untreated and treated patients with coeliac disease were assessed blindly by three independent observers, each of them using different morphometric techniques-namely, linear measurement, stereology, and computer aided microscopy. In two of 26 control biopsy specimens linear measurement was not possible because of distortion o...