Evaluation of an automated, computerized system (automicrobic system) for Enterobacteriaceae identification.

The automated and computerized AutoMicrobic system (AMS; Vitek Systems, Inc., subsidiary of McDonnell Douglas, Hazelwood, Mo.) was evaluated as a means of identifying the Enterobacteriaceae. The Micro-ID system (General Diagnostics, Morris Plains, N.J.) and, when necessary, conventional tubed media were used for comparison. Identification by AMS and Micro-ID differed in only 12 of 1,528 isolates (0.8%). Disagreements occurred primarily with Enterobacter spp. Precision testing of the AMS showed only 1 of 72 tests (1.4%) deviating from the expected. The AMS was found to be an accurate and precise method for the identification of Enterobacteriaceae.     

Molecular definition of a small amplification domain within 3q26 in tumors of cervix, ovary, and lung

A common amplification target encompassing chromosome region 3q25 to q27 has been identified by comparative genomic hybridization analyses in tumors of the cervix, ovary, endometrium, lung, and head and neck. Because this segment spans at least 30 megabases, we undertook a molecular analysis of copy number to more precisely define the amplification domain. Our Southern blot and fluorescence in situ hybridization results with the use of 17 markers confirmed the presence of low-level 3q amplification events in cervical, ovarian, and variant SCLC tumors. Most of the tumor types studied appeared to have similar, broad amplification domains centered within 3q26.2, suggesting that the same target is being affected in all. The ovarian carcinoma cell line NIH:OVCAR3 had a highly restricted amplification domain spanned by four overlapping YAC clones, suggesting a small target. The region of highest amplification included the gene for the RNA component of telomerase (hTR), supporting it as a potential target. Although the importance of low-level amplification is unknown, the consistent and reproducible nature of this event in a variety of carcinomas suggests that 3q26.2 harbors an oncogene whose low-level amplification has a significant influence on tumor biology.     

A microcomputer-based data acquisition system for continuous recording of feeding and drinking by rats

A monitoring system to continuously record the daily pattern of drinking and eating of rats is described. This system, based on a North Star microcomputer, can record the amount of food ingested with a temporal resolution of +/- 1.0 second and quantitative accuracy within +/- 5%. Drinking behavior is detected using a drinkometer which also has a temporal resolution of +/- 1.0 second. Data are analyzed by computer to determine absolute amounts of consumption and patterns of intake. The patterns of feeding and drinking recorded by this system are similar to those observed using other monitoring devices.     

Effect of ageing of serum on consumption of antibody by B1C-globulin determinants; evidence for circulating breakdown products in glomerulonephritis

Changes in antibody consumption by the A and D determinants of β_1C-globulin were found to increase as serum aged in vitro. Consumption by the A determinant was 1·6 times and by the D determinant, 2·5–3 times greater in aged serum than in fresh EDTA plasma. The most likely explanation for the increased consumption with ageing is steric changes occurring as the β_1C molecule fragments into β_1A and α_2D, resulting in exposure of additional antibody combining sites. In specimens from patients with hypocomplementemic nephritis, the increase in consumption with ageing was less than in normal subjects. The data add to the evidence presented in earlier studies of the presence in vivo, in certain nephritics, of breakdown products of β_1C-globulin. The most abundant breakdown product would be α_2D-globulin.     

Statistical evaluation of a quality control method for isolation of pathogenic Vibrio species on selected thiosulfate-citrate-bile salts-sucrose agars

The recovery of Vibrio cholerae, Vibrio fluvialis, Vibrio parahaemolyticus, and Vibrio vulnificus, employing eight strains of each species, was studied by using four brands of thiosulfate-citrate-bile salts-sucrose (TCBS) agar prepared according to manufacturers' instructions and following a standardized procedure. A standardized broth inoculum of each strain was placed on duplicate plates of each brand of TCBS agar and also on tryptic soy agar (Difco Laboratories) containing 1% (wt/vol) NaCl, the latter serving as the control. Plates were inoculated in a sequence designed to compensate for bias associated with multiplication of the bacteria during the inoculation procedure. Colony counts and quality of growth were recorded after incubation for 18 h at 35 degrees C. The comparison procedure was repeated four times at weekly intervals. Data were analyzed by using an analysis of variance model. The recovery and quality of growth of each species varied significantly on the different brands of TCBS agar. Significant variability was also identified for some components of the inoculation procedure. Modifications of the inoculation procedure are suggested to minimize sources of variance. A simplified statistical procedure, based on the t test, is described for media quality control for laboratories routinely isolating pathogenic Vibrio spp.     

Representation of the body in the lateral striatum of the freely moving rat: single neurons related to licking

This study examined the relationship of single-neuron activity (n = 739), recorded from the lateral striatum of freely moving rats, to oral movements involved in licking single drops of liquid. Certain neurons (n = 74) fired specifically in relation to licking. Their firing rates increased during licking, but remained near zero in the absence of licking, throughout a full sensorimotor examination of the remainder of the orofacial area and all other body parts. Another category of neurons (n = 17) fired during licking but also fired in the absence of licking, during one or more other orofacial sensorimotor function(s). Lick-related neurons were located in the lateral striatum, throughout the entire anterior-posterior range studied (from +1.5 to -1.5 mm anterior-posterior, A-P, bregma = 0). Summed over the full A–P range, they were located significantly ventral to representations of the trunk and limbs. These findings extend the characterization of the somatotopic organization exhibited by lateral striatal neurons in the rat, to include representation of oral functions, consistent with converging evidence regarding the functional organization of the striatum.     

Nitric oxide is not permissive for cutaneous active vasodilatation in humans

The precise role of nitric oxide (NO) in cutaneous active vasodilatation in humans is unknown. We tested the hypothesis that NO is necessary to permit the action of an unknown vasodilator. Specifically, we investigated whether a low-dose infusion of exogenous NO, in the form of sodium nitroprusside (SNP), would fully restore vasodilatation in an area of skin in which endogenous NO was inhibited during hyperthermia. This finding would suggest a 'permissive' role for NO in active vasodilatation. Eight subjects were instrumented with three microdialysis fibres in forearm skin. Sites were randomly assigned to (1) Site A: control site; (2) Site B: NO synthase (NOS) inhibition during established hyperthermia; or (3) Site C: NOS inhibition throughout the protocol. Red blood cell flux was measured using laser-Doppler flowmetry (LDF) and cutaneous vascular conductance (CVC; LDF/mean arterial pressure) was normalized to maximal vasodilatation at each site. In Site B, N ^G-nitro- l -arginine methyl ester ( l -NAME) infusion during hyperthermia reduced CVC by ∼32 % (65 ± 4 % CVC_max vs. 45 ± 4 % CVC_max; P < 0.05). Vasodilatation was not restored to pre-NOS inhibition values in this site following low-dose SNP infusion (55 ± 4 % CVC_max vs. 65 ± 4 % CVC_max; P < 0.05). CVC remained significantly lower than the control site with low-dose SNP infusion in Site C ( P < 0.05). The rise in CVC with low-dose SNP (ΔCVC) was significantly greater in Site B and Site C during hyperthermia compared to normothermia ( P < 0.05). No difference in ΔCVC was observed between hyperthermia and normothermia in the control site (Site A). Thus, NO does not act permissively in cutaneous active vasodilatation in humans but may directly mediate vasodilatation and enhance the effect of an unknown active vasodilator.     

Characterizing fibroblast migration on discrete collagen threads for applications in tissue regeneration

Collagen threads with mechanical properties and fibrillar substructure similar to native tissue have been synthesized for the repair of injured tendon and ligament. While these scaffolding materials have demonstrated the potential for inducing tissue regeneration, one limitation has been an insufficient rate of tissue ingrowth for complete regeneration. We hypothesize that the structural hierarchy and biochemical cues on the surfaces of these threads will enhance the rate of cell migration and ultimately the rate of new tissue ingrowth. We developed an in vitro assay to measure the effects of various collagen sources and crosslinking on the rate of fibroblast migration on the surfaces of collagen threads. Threads were suspended from elevated platforms and seeded with fibroblast-populated collagen lattices. Cell migration rates ranging from 0.75 to 1.25 mm/day were measured as the fibroblasts left the lattices and migrated onto various thread types. Threads self-assembled from type I collagen were found to have migration rates similar to native tendon threads while crosslinking by severe dehydration decreased the rate. This novel in vitro model system allows examination of cell migration from a wound margin onto biomaterials to determine the effects of various cell types, matrix materials, and surface biochemistries on cell-matrix interactions. Ultimately, this assay will allow us to identify design parameters that will be most effective for enhancing the rate of tissue ingrowth on fiber-based collagen scaffolds for soft tissue regeneration.