Evaluation of the effects of omega-3 fatty acid-containing diets on the inflammatory stage of wound healing in dogs

OBJECTIVES: To ascertain the effects of dietary omega-3 (n-3) fatty acids on biochemical and histopathologic components of the inflammatory stage of wound healing. ANIMALS: 30 purpose-bred Beagles. PROCEDURE: Dogs were allotted to 5 groups of 6. Each group was fed a unique dietary fatty acid ratio of omega-6 to n-3--diet A, 5.3:1; diet B, 10.4:1; diet C, 24.1:1; diet D, 51.6:1; and diet E, 95.8:1. Dogs were fed once daily for 12 weeks, then biopsy specimens were taken from 4-day-old wounds of each dog and analyzed by gas chromatography-mass spectrometry for: prostaglandin E2 (PGE2) metabolites, and ratios of omega-6 to n-3 fatty acids, arachidonic acid (AA) to eicosapentaenoic acid (EPA), adrenic acid to docosahexaenoic acid, and PGE2 to prostaglandin E3 (PGE3) metabolites. RESULTS: Qualitative analysis was carried out on AA, EPA, adrenic acid, docosahexaenoic acid, and the major metabolite from the PGE2 and PGE3 pathway. These molecules were further quantified with respect to diet to determine significant differences. By analysis of the AA-to-EPA ratio, diet A was different from diets D and E and diets B and C were different from diet E (P < 0.05). By analysis of the PGE2-to-PGE3 metabolite ratio, diet A was different from diet E (P < 0.05). Though biochemical analysis indicated dietary dependence, histopathologic data indicated no significant difference with respect to diet groups. CONCLUSION: The biochemical component of the inflammatory stage of wound healing can be manipulated by diet. CLINICAL RELEVANCE: Omega-3 fatty acid-enriched diets can be used to control inflammation associated with dermatologic conditions.     

Determinants of glutamine dependence and utilization by normal and tumor-derived breast cell lines

A continual supply of the amino acid glutamine (GLN) may be necessary for cancerous cell growth. GLN plays a central role in multiple metabolic pathways and has long been considered an essential component of tissue culture media. However, the GLN requirements of tumor cell lines and the factors that determine a cell's need for GLN have not been comprehensively studied. Also, it remains unclear how various metabolic pathways contribute to GLN consumption. In the present study, possible determinants of GLN metabolism were examined in seven breast cell lines, two derived from immortalized normal tissue and five of tumor origin. These cells exhibited different dependencies on media GLN concentration for growth and a wide range of GLN utilization rates. GLN uptake was facilitated by a single, common transporter functionally defined as System ASC. However, the affinities for GLN exhibited by this transporter differed appreciably between cell lines. Furthermore, the concentration at which media GLN became a limiting factor for cellular proliferation correlated with transporter affinity. The origin of the cell lines was not a determinant of GLN metabolism because immortalized cells of nontumor origin exhibited GLN dependence and utilization rates comparable to those of tumor-derived cells. The rates of CO2 production from GLN were similar for each cell lines. Rates of GLN disappearance and glutamate appearance in media were strongly correlated, with 32-80% of media GLN converted to glutamate. Both rates were directly affected by media cystine concentration, suggesting that a large portion of glutamate efflux was coupled with cystine import through the amino acid transport system x(c)-. These results demonstrated that cell growth is a function of GLN influx and suggest that GLN is used to supply glutamate and cystine, perhaps for glutathione synthesis.     

Identification of novel simple sequence length polymorphisms (SSLPs) in mouse by interspersed repetitive element (IRE)-PCR

Interspersed repetitive element (IRE)-PCR is a useful method for identification of novel human or mouse sequence tagged sites (STSs) from contigs of genomic clones. We describe the use of IRE-PCR with mouse B1 repetitive element primers to generate novel, PCR amplifiable, simple sequence length polymorphisms (SSLPs) from yeast artificial chromosome (YAC) clones containing regions of mouse chromosomes 13 and 14. Forty-two IRE-PCR products were cloned and sequenced from eight YACs. Of these, 29 clones contained multiple simple sequence repeat units. PCR analysis with primers derived from unique sequences flanking the simple sequence repeat units in seven clones showed all to be polymorphic between various mouse strains. This novel approach to SSLP identification represents an efficient method for saturating a genomic interval with polymorphic genetic markers that may expedite the positional cloning of genes for traits and diseases.     

The anatomic basis and clinical applications of flaps based on the posterior tibial vessels

The vascular anatomy of the posterior tibial vessels has been studied in 20 legs of 10 cadavers. The number, size and distribution of the direct cutaneous and direct muscle branches of the posterior tibial vessels were recorded. For analysis, the leg was divided into four equal segments, Zone I being the most distal and Zone IV the most proximal. The direct cutaneous branches were found to cluster mainly around Zone II. The direct muscle branches to the soleus and flexor digitorum longus muscles arose chiefly in Zones II and III. Based on this knowledge, we performed fasciocutaneous, island soleus muscle, musculo-fasciocutaneous and flexor digitorum longus muscle flaps based on the posterior tibial vessels in 12 patients. Four were free fasciocutaneous flaps and eight were pedicled flaps. All flaps survived and there were no major complications. Delayed wound healing was encountered in three patients.     

Reinduction of the hypnotic effects of thiopental with NSAIDs by decreasing thiopental plasma protein binding in humans

The angioscopic evaluation of the carotid bifurcation has proved valuable for intraoperative quality control after carotid endarterectomy (CEA). From January 1989 to July 1990, intraoperative angioscopy was performed in 196 patients undergoing CEA. We used a 2.2, 2.8 or 3.6 mm angioscope inserted at the end of the CEA through the remaining opening in the suture line. The angioscopic findings were classified as follows: I--no pathology (68%), II--thrombi, smaller debris, suture irregularities (29%), III--intima flap, endoscopic removal (3%), IV--intima flap, surgical redo (3%). Our results support the practicability and importance of intraoperative angioscopy for surgical decision making. It is possible to rinse out thrombi or remove remaining debris using flexible forcepy, under direct visual control. There were no significant complications related to the angioscopic procedure.     

Micromolar L-glutamate induces extensive apoptosis in an apoptotic-necrotic continuum of insult-dependent, excitotoxic injury in cultured cortical neurones

Excitotoxicity induced by L-glutamate (Glu), when examined in a pure neuronal cortical culture, involved widespread apoptosis at concentrations of 1-10 microM as part of a continuum of injury, which at its most servere was purely necrotic. Cells, maintained in chemically defined neurobasal/B27 medium, were exposed at d7 for 2 h to Glu (1-500 microM), and cellular injury was analysed 2 and 24 h after insult using morphology (phase-contrast microscopy), a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) viability assay, nuclear staining with 4,6-diamidino-2-phenylindole (DAPI), terminal transferase-mediated dUTP nick end-labelling (TUNEL) and DNA fragmentation by gel electrophoresis. Glu-mediated neurotoxicity was prevented by MK-801 (5 microM), whilst CNQX (20 microM) attenuated injury by 20%. Exposure to intensive insults (100 and 500 microM Glu) induced necrosis characterized by rapid cell swelling (< 2 h) and lack of chromatin condensation, confirmed by DAPI nuclear staining. In contrast, mild insults (< 20 microM Glu) failed to produce acute neuronal swelling at < 2 h, but 24 h after injury resulted in a large number of apoptotic nuclei as confirmed by TUNEL and electrophoretic evidence of DNA fragmentation, which was attenuated by cycloheximide (0.1 microg/ml). Our findings indicate for the first time that physiological concentrations of Glu produce neuronal injury across a continuum involving apoptosis (< 20 microM) and increasingly necrosis(> 20 microM), dependent on the severity of the initial insult.