Heterogeneity in the accessory olfactory system

The mammalian accessory olfactory bulb (AOB) is chemoarchitecturally heterogeneous in that it stains differentially with a number of markers; the receptor cells that project to the AOB are similarly heterogeneous. What is the significance of this heterogeneity? We have found that the AOB of the gray, short-tailed opossum, Monodelphis domestica, stains differentially with a number of 'markers': antibodies to olfactory marker protein (OMP) and the alpha subunit of the G protein Gi2, the lectin of Vicia villosa and NADPH-diaphorase. These markers stain the rostral AOB more strongly than the caudal AOB whereas, the G protein subunit G(o) alpha is located predominantly in the posterior subdivision of the AOB. This heterogeneity in the chemoarchitecture of the AOB may reflect a fundamental organizational dichotomy within the vomeronasal system that corresponds to a functional dichotomy. The vomeronasal sensory epithelium also exhibits a chemoarchitectural heterogeneity: receptor cells in the basal third are G(o) alpha-immunoreactive whereas the cells in the middle third are Gi2 alpha-immunoreactive. Tracing studies using WGA-HRP demonstrate that the neurons in the middle third of the vomeronasal sensory epithelium project their axons to the anterior AOB whereas those in the basal third appear to project to the posterior AOB.

[The effect of ultrapure hyaluronic acid with different molecular weights on the healing of porcine full thickness skin wound]

Hyaluronic acid (HA) is an extracellular matrix having a high molecular weight. This study is to investigate (1) whether the ultrapure HA had effect on the healing of full thickness skin wounds in animals, and (2) the relation between the effect of HA and the size of the molecular weight of HA. The ultrapure HA with different molecular weights and HA with intermediate molecular weight were applied topically to the wounds from removal of full thickness of skin and topical application of normal saline was used as control. At 21st, day after the topical application, the tensile strength was reduced in wounds of groups of HA with high and intermediate molecular weights, but not in the group of low molecular weight. Using laser-Doppler scanning of the dynamic changes of the wound perfusion, in the 3rd day the blood supply to the wound was reduced in HA groups of high and intermediate molecular weights, but at the 7th day, the blood supply of all wounds in the two groups was increased. The study revealed that HA with different molecular weights had different actions on the contraction of wounds, the angiogenesis of the granulation tissues and the healing strength of the wounds. It was indicated that hyaluronan could be used for wound treatment or as a carrier, but its accurate composition must be carefully noted.

Segregated pathways in the vomeronasal system

The vomeronasal system of mammals is chemoarchitecturally dichotomous. Two populations of receptor cells have been identified in the vomeronasal sensory epithelium based on the family of receptor proteins they express on their membranes. These two receptor cell populations express different G-proteins: the more basal population expresses Goalpha and the more apical population expresses Gialpha2. The Goalpha-expressing receptor cells project their axons to the posterior accessory olfactory bulb (AOB) whereas the Gialpha2-expressing cells project their axons to the anterior AOB. In all mammals studied to date, the anterior AOB is Gialpha2-positive and the posterior AOB is Goalpha-positive. These two parts of the AOB are also chemoarchitecturally heterogeneous with respect to their carbohydrate content as revealed both with lectin binding and immunoreactivity to monoclonal antibodies raised against carbohydrate moieties. However, species differences have been observed with respect to lectin binding, as with NADPH-diaphorase reactions and OMP immunoreactivity. Recent studies indicate that there are physiological and behavioral correlates to the dichotomy within the vomeronasal system.

[Association of apoB levels and nutrition of coronary heart disease patients]

Blood lipids and apo B levels were measured on 101 Coronary Heart Disease patients and 100 controls. The results showed that the apo B levels of patients were higher than that of controls. The average values were (877 +/- 129) mg/L and (800 +/- 95) mg/L respectively. It was found that there was close association among body mass index(BMI), ratio of waist circumference to hip circumference(WHR) and apo B levels. Besides, the results showed that dietary habit of "eating fat meat" might result in the increase of apo B concentration while the VC intake was negatively associated with serum apo B levels.

[A 24-hour solid state Holter recording and analyzing system]

The design and functions of a new type of multi-channel solid-state Holter system were introduced in this paper. The flash memory card based recorder can record 24 hours or more of data from up to all 12 leads. The full function scanner software can analysis automatically and archive with complete editing capabilities.

Development of vomeronasal receptor neuron subclasses and establishment of topographic projections to the accessory olfactory bulb

Previous studies of the adult vomeronasal system have shown that vomeronasal receptor neurons in the middle layer (expressing Gi alpha 2) and deep layers (expressing Go alpha) of the sensory epithelium project to the anterior and posterior parts of the accessory olfactory bulb (AOB), respectively. In the present study, the development of the two populations of vomeronasal receptor neurons and their segregated projections were investigated in the opossum, Monodelphis domestica. Antibodies to G proteins Gi alpha 2 and Go alpha were used to identify the two subpopulations of receptor neurons. The Gi alpha 2-immunoreactive (ir) cells and Go alpha-ir cells appeared between postnatal day 0 (P0) and postnatal day 3 (P3) and both types of cells increased in number during later development. The differential localization of Gi alpha 2-ir cells in the middle layer and Go alpha-ir cells in the deep layer of the VNO could be seen as early as P3 and became more prominent at later stages. The AOB was clearly identified at P10, and at this stage segregated projections of Gi alpha 2-ir fibers to the anterior part and Go alpha-ir fibers to the posterior part of the AOB were seen. The segregation of the two types of fibers in the AOB resemble that in the adult after P21. These results suggest that Gi alpha 2-ir and Go alpha-ir subpopulations of receptor neurons in the VNO develop in parallel, and that segregation of the two populations of receptor neurons in the VNO and the topographic projection to the AOB are established at very early stages during development.

Segregated populations of mitral/tufted cells in the accessory olfactory bulb

The dendritic distribution of mitral/tufted (M/T) cells in the opossum accessory olfactory bulb (AOB) was investigated using intracellular injection of Lucifer yellow and DiI labeling. Lucifer yellow labeling demonstrated that the primary dendrites of M/T cells are restricted to one of the two subregions (anterior or posterior) of the glomerular layer. When DiI was placed in the anterior or posterior subregion of the glomerular layer, virtually all of the labeled cell bodies in the AOB were located in the anterior or posterior part of the M/T cell layer, respectively. These results demonstrate that the anterior and posterior subregions of the AOB glomerular layer are termination sites for dendrites belonging to distinct populations of M/T cells.

[Prediction of skin flap viability by laser Doppler scanning]

Twelve female pigs were used for the experiment. An island flap (8 cm x 15 cm) pedicled with the superficial circumflex iliac vessels was elevated on the flank of the pig. The blood flow of the flap was measured with laser doppler scanning at different times, i.e. before and after flap elevation; before clipping the feeding artery of the flap and 9 hours after clipping the artery; 5 minutes, 20 minutes, 40 minutes, 1 hour and 40 hours after reperfusion. The flap viability was also examined with naked eye and fluorography. Biopsy examinations were used as gold standard of flap viability. The results showed that predicting accuracy of flap viability by naked eye was 76%; fluorography was 94% and laser doppler scanning was 91.3%. No significant difference was found between the results from fluorography and laser doppler scanning while there was significant difference between naked eye and laser doppler scanning. The authors discussed the clinical applications of predicting skin flap viability.

Subclasses of vomeronasal receptor neurons: differential expression of G proteins (Gi alpha 2 and G(o alpha)) and segregated projections to the accessory olfactory bulb

Differential expression of G proteins (Gi alpha 2 and G(o alpha) and the separate central projections of Gi alpha 2- and G(o alpha)-immunoreactive (ir) vomeronasal receptor neurons were investigated in the mouse and rat using immunocytochemical methods. In the vomeronasal organ (VNO), receptor neurons with their cell bodies located in the middle layer (middle 1/3) of the vomeronasal sensory epithelium express Gi alpha 2. Axons of these Gi alpha 2-ir neurons can be followed from VNO to the anterior part, but not the posterior part, of the nerve-glomerular (N-GL) layer of the accessory olfactory bulb (AOB). Another population of receptor neurons, which are located in the deep layer (basal 1/3) of the vomeronasal sensory epithelium, express G(o alpha), and axons of the G(o alpha)-ir neurons can be traced to the posterior part, but not the anterior part, of the N-GL layers of the AOB. The axons of the two subclasses of receptor neurons are intermingled near the VNO and become segregated as they enter the AOB. Removal of the AOB results in retrograde degeneration of both Gi alpha 2-ir and G(o alpha)-ir receptor neurons in the VNO. These results suggest that at least two subclasses of receptor neurons exist in the VNO: the Gi alpha 2-ir neurons in the middle layer and the G(o alpha)-ir neurons in the deep layer of the VNO. The Gi alpha 2-ir neurons in the middle layer of the VNO project to the anterior part of the AOB, while the G(o alpha)-ir neurons in the deep layer of the VNO project to the posterior half of the AOB. These results are similar to our previous observations in the gray short-tailed opossum, suggesting that the existence of at least two subclasses of receptor neurons in the vomeronasal epithelium with differential projections to the AOB is a conserved feature among mammals.

[Preliminary study on multi-resistant gene location of 20 strains of Pseudomonas aeruginosa]

20 strains of Pseudomonas aeruginosa were isolated from burn patients of Xijing Hospital in Xi'an. These 20 strains which showed resistance to multiple antibiotics were selected to be studied regarding the location of multi-resistant gene. According to the sensitivity tests before and after plasmid removal, we found that in 70% of the bacteria resistance to multiple antibiotics was mediated by the plasmid. In 30% the bacteria remained resistant to antibiotics after plasmids were removed. Two explanations were postulated. (1) plasmids were not removed completely; (2) resistance gene was encoded by the chromosomes.

Hyaluronan, heterogeneity, and healing: The effects of ultrapure hyaluronan of defined molecular size on the repair of full-thickness pig skin wounds

The extracellular matrix macromolecule, hyaluronan, is thought to modulate wound healing. However, the molecular size of hyaluronan and contaminating associated proteins may be important determinants of these effects. We have examined the results of seven daily topical treatments of full-thickness skin wounds in pigs with ultrapure hyaluronan of defined molecular size. High molecular weight hyaluronan (>1000 kd) enhanced, whereas low molecular weight hyaluronan decreased, the rate of early wound contraction as compared with intermediate hyaluronan (molecular weight = 100 kd) and saline solution controls. Fracture strength at 21 days was reduced by high and intermediate molecular weight hyaluronan but not by low molecular weight hyaluronan. Wound perfusion, measured by means of a scanning laser-Doppler technique as a noninvasive indicator of angiogenesis, showed depression by high and intermediate molecular weight hyaluronan on day 3, but all forms of hyaluronan caused elevated blood flow on day 7. The architecture of granulation tissue in this wet healing model was highly organized, but no gross histologic differences were seen because of treatment. Different molecular species of hyaluronan have differential effects on contraction, angiogenesis, and the evolution of wound strength. Where hyaluronan is used as a treatment or vehicle for wounds, its precise composition should be specified.

[A 3-year follow-up study of 50 children with acute lymphoblastic leukemia]

Fifty children with acute lymphoblastic leukemia were followed up for an average period of 3 3/12 years. The results showed that 19 (38%) cases were given up after diagnosis. Eight patients only received treatment irregularly for 1 year; among them, 2 discontinued therapy by themselves for 2-3 years and survived free of events, and 6 were lost, Twenty-three received treatment regularly; among them, 3 died of infection, 11 were in continuously complete remission and 9 experienced relapse. The total disease-free survival rate for mean 3 3/12 years is 42% (13/31), exclusive of the 19 given up cases. Statistical analysis indicates a higher relapse rate in those cases with lower initial glucocorticoid receptors (GCR) of peripheral blood lymphocytes.

Differential localization of G proteins in the opossum vomeronasal system

Gi2 alpha and G(o) alpha proteins were immunohistochemically localized, respectively, to the rostral and caudal accessory olfactory bulb of Brazilian opossums. In the vomeronasal organ, Gi2 alpha- and G(o) alpha-immunoreactive neurons were located in the middle and basal layers, respectively, of the sensory epithelium. Both G protein antibodies stained the microvillar surface of the epithelium and the nerve bundles in the subepithelial mucosa.

Two-dimensional gas chromatography for the enantiomeric separation of ephedrine and phenaminum and their metabolites

Two-dimensional gas chromatography was used for enantiomeric separation of ephedrine, phenaminum and their metabolites in human urine. The main column was coated with a 2,6-di-O-pentyl-3-O-trifluoroacetylated-alpha-cyclodextrin and an SE-54 phase column was used as precolumn. The results showed that two-dimensional chromatography could greatly simplify the sample preparation, eliminate the interference of sample matrices, and improve the resolution of the enantiomers of interest.

Evidence for two different nitrate-reducing activities at the plasma membrane in roots of Zea mays L

Plasma-membrane (PM) vesicles isolated from 6-d-old corn roots by sucrose gradient centrifugation or two-phase partitioning showed an NADH-dependent nitrate reductase (NR) activity averaging at 40 nmol per milligram PM protein per hour. This membrane-associated NR activity could not be removed from two-phase partitioned PM vesicles by salt washing, osmotic shock treatment, sonication, or freeze-thawing to reverse vesicle sidedness. Therefore, it could not be attributed to contamination of membrane vesicles by the soluble, cytosolic NR. Plasma-membrane vesicles reduced NO~ in the presence of the electron donors NADH or NADPH at an activity ratio of 2.2. The NADH- and NADPH-dependent NR activities of outside-out oriented PM vesicles differed in their sensitivity toward the detergent Brij 58,leading to a latency of 65% or 29% using NADH or NADPH as electron donor, respectively. The activities of NO 3 reduction in the presence of saturating concentrations of NADH and NADPH were additive. Furthermore,both activities were characterized by a different pH dependence with a pH optimum of 7.5 for the NADH-dependent activity and of 6.8 for the NADPH-dependent activity. The membrane-associated NAD(P)H-dependent NR activities responded to different nitrogen nutrition of plants in a manner different from the soluble forms of the enzyme. The data confirm the existence of a corn PM NR and suggest that there may be two different NO₃-reducing enzymes located at the PM of corn roots.