Elastic modulus of trabecular bone material

An ultrasonic technique was used to measure both the elastic modulus (Young's modulus) of trabecular bone material and the elastic modulus of the cancellous structure. The average trabecular modulus, measured on specimens obtained from three human and one bovine distal femora, was 13.0 GPa (S.D. 1.47) and 10.9 GPa (S.D. 1.57), respectively. On human specimens the structural elastic modulus was found to be related to the structural (apparent) density raised to the 1.88 power. The elastic modulus from the bovine specimens showed a more linear relationship with the density of the cancellous structure (density raised to the 1.57 power).     

A search for porphyrin biomarkers in nonesuch shale and extraterrestrial samples

An organic solvent extract of billion year old Nonesuch Shale was examined for porphyrins by means of fluorometry and high resolution mass spectrometry. It appears to contain at least three or more classes of porphyrins, one similar to tetraphenyl porphin and the others more complex. Many are apparently chelated with copper, nickel, zinc, iron and vanadyl and are highly aromatic. We have also examined the extracts of Apollo 11, 12 and 14 surface fines for pophyrins by spectrophotofluorometry but we found none even though our method was capable of detecting 10⁻¹³ moles per gm of sample. Lunar Science Institute Contribution.     

Epidemic Enteropathogenic Escherichia Coli,Newfoundland, 1963: Autopsy Study of 16 Cases

The autopsy findings and certain other features are described in 16 fatal cases of infantile diarrhea associated with enteropathogenic Escherichia coli infection during the 1963 epidemic in Newfoundland which resulted in 100 deaths. Age is an important factor in the severity of the infection and in the outcome. Almost one-half the patients were under 4 months and a third under 2 months. Pathological changes in the gastrointestinal tract were meagre and were not pathognomonic. Other pathological findings and their possible role in the severity and fatal outcome in enteropathogenic Escherichia coli gastroenteritis are discussed. Such conditions as prematurity, congenital anomaly, trauma, neoplasm and metabolic disorders were, no doubt, also important factors in the outcome. Severe respiratory tract infection was the leading terminal cause of death. No sex, seasonal or geographic variation was found. Enteropathogenic Escherichia coli serotype 0111:B4 was the prevalent infecting organism.     

Specific-sized Hyaluronan Fragments Promote Expression of Human β-Defensin 2 in Intestinal Epithelium

Hyaluronan (HA) is a glycosaminoglycan polymer found in the extracellular matrix of virtually all mammalian tissues. Recent work has suggested a role for small, fragmented HA polymers in initiating innate defense responses in immune cells, endothelium, and epidermis through interaction with innate molecular pattern recognition receptors, such as TLR4. Despite these advances, little is known regarding the effect of fragmented HA at the intestinal epithelium, where numerous pattern recognition receptors act as sentinels of an innate defense response that maintains epithelial barrier integrity in the presence of abundant and diverse microbial challenges. Here we report that HA fragments promote expression of the innate antimicrobial peptide human β-defensin 2 (HβD2) in intestinal epithelial cells. Treatment of HT-29 colonic epithelial cells with HA fragment preparations resulted in time- and dose-dependent up-regulated expression of HβD2 protein in a fragment size-specific manner, with 35-kDa HA fragment preparations emerging as the most potent inducers of intracellular HβD2. Furthermore, oral administration of specific-sized HA fragments promotes the expression of an HβD2 ortholog in the colonic epithelium of both wild-type and CD44-deficient mice but not in TLR4-deficient mice. Together, our observations suggest that a highly size-specific, TLR4-dependent, innate defense response to fragmented HA contributes to intestinal epithelium barrier defense through the induction of intracellular HβD2 protein.     

Adamantyl N-benzylbenzamide: new series of depigmentation agents with tyrosinase inhibitory activity

A new series of polyhydroxylated N-benzylbenzamide derivatives containing an adamantyl moiety has been synthesized, and the depigmenting and tyrosinase inhibitory activities of the molecules were evaluated. The lipophilic character of the adamantyl moiety appeared to confer greater depigmentation power on the benzamide derivatives as compared to those lacking adamantyl substitution. Molecular modeling was applied in order to elucidate the interactions between ligands and tyrosinase that led to inhibition.