Improved method for determination of abamectin and ivermectin in cattle plasma

A liquid chromatographic (LC) method was developed for determination of abamectin (ABM) and ivermectin (IVM) in cattle plasma. The sample was extracted with acetonitrile and cleaned up on an alumina column. After conversion to stable fluorescent derivative with trifluoroacetic anhydride and N-methylimidazole, the sample was analyzed by LC with fluorescence detection (Ex 365 nm and Em 475 nm). Doramectin was used as an internal standard. Recoveries ranged from 91.2 to 100.7% for IVM and from 87.0 to 98.7% for ABM, with 1-50 ng/mL fortified samples. The coefficients of variation were <10.1%. The limit of detection was 0.02 ng/mL for ABM and IVM in 1.0 mL samples.

Resolution of the essential constituents of Ramulus cinnamomi by an evolving chemometric approach

The analysis of complex mixtures, such as those of traditional Chinese medicine (TCM), is difficult by conventional methods of analysis. Chemometric methods provide a new way to solve such problems. Subwindow factor analysis (SFA) paired with the evolving window orthogonal projection (EWOP) method, has been used as a new evolving approach to the resolution of volatile components of Ramulus cinnamomi (RC). Compared with conventional chromatographic analysis, the chromatographic separation conditions necessary are greatly mitigated in our approach, yet the accuracy of qualitative and quantitative results is improved, because the measured data matrix has been resolved into chromatograms and mass spectra of the chemical components. Our method is, moreover, friendly to use and easy to program. Experimental results show the efficiency and convenience of the proposed approach. Forty-seven of the seventy-eight separated constituents in an essential oil, accounting for 89.55% of the sample, were identified by mass spectroscopy (MS).

Correlation between electrophysiology and morphology of three groups of neuron in the dorsal commissural nucleus of lumbosacral spinal cord of mature rats studied in vitro

The dorsal commissural nucleus (DCN) in the lumbosacral spinal cord receives afferent inputs from the pelvic organs via pudendal and pelvic nerves. Electrophysiological and morphological properties of neurons in the DCN of L6-S1 were examined using whole-cell recordings with biocytin-filled electrodes in transverse slices of mature rat spinal cord. Neurons were categorized into three groups according to their discharge in response to suprathreshold depolarizing pulses; neurons with tonic (19/42) and phasic (13/42) firing patterns, and neurons (10/42) that fired in bursts arising from a Ca(2+)-dependent hump. The predominantly fusiform somata of neurons labeled during recording (n = 31) had on average 3.1 primary dendrites, 7.5 terminating dendritic branches, 3.1 axon collaterals, and 14.2 axon terminations per neuron. The groups were morphologically distinct on the basis of their dendritic branching patterns. Phasic neurons (n = 10) had the most elaborate dendritic branching and the largest numbers of axon collaterals. All tonic neurons (n = 11) had axons/collaterals projecting to the intermediolateral area but none to the funiculi, suggesting that they function as interneurons in local autonomic reflexes. Many axons/collaterals of all phasic neurons lay within the DCN, suggesting that they integrate segmental and descending inputs. Seven of 10 neurons with Ca(2+)-dependent humps had axons/collaterals extending into one of the funiculi, suggesting that they project intersegmentally or to the brain. Ca(2+) hump neurons also had more axons/collaterals within the DCN and fewer in the intermediolateral area than tonic neurons. This correlation between firing pattern and morphology is an important step toward defining the cellular pathways regulating pelvic function.

Glutamine enhances the gut-trophic effect of growth hormone in rat after massive small bowel resection

Background. Bowel-specific nutrient, glutamine, growth hormone, and modified diet have been reported to jointly improve nutrient absorption in patients with short bowel syndrome. However, controversy exists about the exact treatment factor. In this study we attempted to analyze the individual and combined effect of glutamine supplementation and growth hormone on small bowel adaptation by using tube feeding to control luminal nutrition supply. Materials and methods. Thirty-two adult male Sprague-Dawley rats (278 +/- 8 g) underwent 85% mid-small bowel resection and were randomly assigned to four groups: Control, receiving control liquid diet via a gastrotomy tube; GLN, receiving liquid diet enriched with 20 g. L(-1) glutamine; GH, receiving subcutaneous growth hormone (GH) (0.3 IU, bid); and GLN + GH, receiving both glutamine supplementation and GH treatment. All animals were provided with isocaloric (60 kcal/day) and isonitrogenous (0.686 g/day) nutrition. Absorption tests were performed in the form of oral nutrient tests with (14)C-labeled glucose and (3)H-labeled palmitic acid on the Postoperative Day 12. Results. GH treatment significantly increased the plasma insulin-like growth factor I (IGF-I) level, body weight, jejunal and ileal villous height and mucosal thickness, and peak plasma (14)C and (3)H levels. Glutamine supplementation did not produce a significant difference; however, combined with GH treatment, glutamine supplementation further increased body weight, plasma IGF-I level, jejunal and ileal villous height and mucosal thickness, and peak plasma (14)C and (3)H levels significantly. Conclusions. After massive small bowel resection, enteral glutamine supplementation alone has no remarkable beneficial effect on bowel adaptation. However, glutamine supplementation enhanced the gut-trophic effect of GH.

[Research on DNA molecular marker of Magnolia officinalis Rehd. et Wils.--RAPD study on certified species]

AIM

To discuss the intraspecific relationship in Magnolia officinalis and the genuineness of Cortex Magnoliae officinalis, and to find some DNA characters of certified "Houpo".

METHODS

Thirty-three samples from eleven locations, which can represent most of the distribution of M. officinalis, were selected. The total DNA was extracted. Severty-four random primers were tried to get good amplification.

RESULTS

One hundred and sixteen bands amplified from seventeen primers, were clustered by NTSYS-pc software. Three branches were obtained. Some distinctive primers and bands, which represent certified species or fine breed, were obtained also.

CONCLUSION

1) M. officinalis should be divided into three geographic clans instead of two subspecies or varieties, they are, a) typical officinalis, b) typical biloba and c) Middle type. This conclusion agrees with the leaf form and other characters. 2) The genetic difference between "Chuanpo" and "Wenpo" is evident and the difference is in correspondence with the quantities of their chemical constituents. So, the genetic difference is the main reason of the genuineness of Cortex Magnoliae officinalis. 3) These results may be used to establish DNA database for identification of Cortex Magnoliae officinalis.

Distribution of double-negative (CD4- CD8-, DN) T subsets in blood and synovial fluid from patients with rheumatoid arthritis

Double-negative (CD4- CD8-) T (DNT) cells have been postulated to be potentially autoreactive. However, the role of DNT cells in rheumatoid arthritis (RA) has received limited attention. We investigated the distribution of DNT subsets in peripheral blood (PB) and synovial fluid (SF) from patients with active RA to determine whether these cells have relevance to RA. Two-colour flow cytometric analysis was performed to detect DNT cells in PB from 35 RA patients, 26 healthy controls and in SF aspirated from 19 inflamed rheumatoid joints. The subsets of DNT cells, i.e those expressing T cell receptor alphabeta (alphabeta DNT) or gammadelta (gammadelta DNT) were simultaneously examined. Our results showed that DNT cells constituted a very minor subset of PB lymphocytes. When expressed as a percentage of total lymphocytes, alphabeta DNT levels in normal individuals ranged from 0.27 to 2.08% (average 0.76%), while those of gammadelta DNT ranged from 1.02 to 11.42% (average 3.23%). Compared with normal individuals, RA patients had a similar distribution of alphabeta DNT cells in both PB and SF. However, RA patients had significantly lower levels of gammadelta DNT cells in PB than control subjects (1.38 +/- 1.08% vs 3.23 +/- 2.12%, p<0.05), while the levels of gammadelta DNT cells in SF of RA patients were higher than those in PB from RA patients and normal controls. The difference between PB and SF in RA was statistically significant (3.90 +/- 1.88% vs 1.38 +/- 1.08%, p<0.05). A higher level of gammadelta DNT in SF than their paired PB was consistently noted from nine available paired samples. Our findings suggest that gammadelta NT cells, but not alphabeta DNT cells, are probably relevant to RA. The lower percentage of circulating gammadelta DNT cells might have resulted from migration from the circulation into the synovium, suggesting a role for gammadelta DNT cells in the pathogenesis of rheumatoid synovitis.

Effect of bowel rehabilitative therapy on structural adaptation of remnant small intestine: animal experiment

AIM: To investigate the individual and the combined effects of glutamine, dietary fiber, and growth hormone on the structural adaptation of the remnant small bowel.

METHODS: Forty-two adult male Sprague-Dawley rats underwent 85% mid-small bowel resection and received total parenteral nutrition (TPN) support during the first three postoperational days. From the 4th postoperational day, animals were randomly assigned to receive 7 different treatments for 8 d: TPNcon group, receiving TPN and enteral 20 g·L^-1 glycine perfusion; TPN + Gln group, receiving TPN and enteral 20 g·L^-1 glutamine perfusion; ENcon group, receiving enteral nutrition (EN) fortified with 20 g·L^-1 glycine; EN + Gln group, enteral nutrition fortified with 20 g·L^-1 glutamine; EN + Fib group, enteral nutrition and 2 g·L^-1 oral soybean fiber; EN + GH group, enteral nutrition and subcutaneous growth hormone (GH) (0.3IU) injection twice daily; and ENint group, glutamine-enriched EN, oral soybean fiber, and subcutaneous GH injection.

RESULTS: Enteral glutamine perfusion during TPN increased the small intestinal villus height (jejunal villus height 250 µm ± 29 µm in TPNcon vs 330 µm ± 54 µm in TPN + Gln, ileal villus height 260 µm ± 28 µm in TPNcon vs 330 µm ± 22 µm in TPN + Gln, P < 0.05) and mucosa thickness (jejunal mucosa thickness 360 µm ± 32 µm in TPNcon vs 460 µm ± 65 µm in TPN +Gln, ileal mucosa thickness 400 µm ± 25 µm in TPNcon vs 490 µm ± 11 µm in TPN + Gln, P < 0.05) in comparison with the TPNcon group. Either fiber supplementation or GH administration improved body mass gain (end body weight 270 g ± 3.6 g in EN + Fib, 265.7 g ± 3.3 g in EN + GH, vs 257 g ± 3.3 g in ENcon, P < 0.05), elevated plasma insulin-like growth factor (IGF-I) level (880 µg·L^-1± 52 µg·L^-1 in EN + Fib, 1200 µg·L^-1± 96 µg·L^-1 in EN ± GH, vs 620 µg·L^-1± 43 µg·L^-1 in ENcon, P < 0.05), and increased the villus height (jejunum 560 µm ± 44 µm in EN ± Fib, 530 µm ± 30 µm in EN ± GH, vs 450 µm ± 44 µm in ENcon, ileum 400 µm ± 30 µm in EN + Fib, 380 µm ± 49 µm in EN ± GH, vs 320 µm ± 16 µm in ENcon, P < 0.05) and the mucosa thickness (jejunum 740 µm ± 66 µm in EN ± Fib, 705 µm ± 27 µm in ENGH, vs 608 µm ± 58 µm in ENcon, ileum 570 µm ± 27 µm in EN ± Fib, 560 µm ± 56 µm in EN ± GH, vs 480 µm ± 40 µm in ENcon, P < 0.05) in remnant jejunum and ileum. Glutamine-enriched EN produced little effect in body mass, plasma IGF-I level, and remnant small bowel mucosal structure. The ENint group had greater body mass (280 g ± 2.2 g), plasma IGF-I level (1450 µg·L^-1± 137 µg·L^-1), and villus height (jejunum 620 µm ± 56 µm, ileum 450 µm ± 31 µm) and mucosal thickness (jejunum 800 µm ± 52 µm, ileum 633 µm ± 33 µm) than those in ENcon, EN + Gln (jejunum villus height and mucosa thickness 450 µm ± 47 µm and 610 µm ± 63 µm, ileum villus height and mucosa thickness 330 µm ± 39 µm and 500 µm ± 52 µm), EN + GH groups (P < 0.05), and than those in EN + Fib group although no statistical significance was attained.

CONCLUSION: Both dietary fiber and GH when used separately can enhance the postresectional small bowel structural adaptation. Simultaneous use of these two gut-trophic factors can produce synergistic effects on small bowel structural adaptation. Enteral glutamine perfusion is beneficial in preserving small bowel mucosal structure during TPN, but has little beneficial effect during EN.

Outer membrane protein-specific monoclonal antibodies protect SCID mice from fatal infection by the obligate intracellular bacterial pathogen Ehrlichia chaffeensis

Previous studies of Ehrlichia chaffeensis infection in the mouse have demonstrated that passive transfer of polyclonal Abs from resistant immunocompetent mice to susceptible SCID mice ameliorated infection and disease, even when Abs were administered during established infection. To identify particular Abs that could mediate bacterial clearance in vivo, E. chaffeensis-specific mAbs were generated and administered to infected SCID mice. Bacterial infection in the livers was significantly lowered after administration of either of two Abs of different isotypes (IgG2a and IgG3). Moreover, repeated administration of one Ab (Ec56.5; IgG2a) rescued mice from an otherwise lethal infection for at least 5 wk. Both protective Abs recognized the E. chaffeensis major outer membrane protein (OMP)-1g. Further studies revealed that both Abs recognized closely related epitopes within the amino terminus of the first hypervariable region of OMP-1g. Analyses of human sera showed that E. chaffeensis-infected patients also generated serological responses to OMP-1g hypervariable region 1, indicating that humans and mice recognize identical or closely related epitopes. These studies demonstrate that OMP-specific mAbs can mediate bacterial elimination in SCID mice, and indicate that Abs, in the absence of cell-mediated immunity, can play a significant role in host defense during infection by this obligate intracellular bacterium.

Viable rabbits derived from reconstructed oocytes by germinal vesicle transfer after intracytoplasmic sperm injection (ICSI)

Abnormal oocyte spindle due to the improper function of ooplasm is associated with female infertility of advanced maternal age. A possible way to overcome this problem is to transfer an oocyte germinal vesicle (GV) which contains genetic materials of a patient with a history of poor embryo development to the cytoplast from a donor oocyte. Here we demonstrate that GV transfer is feasible using a rabbit model. When the GVs were transferred to auto- or hetero-cytoplasts of GV stage oocytes, around 80% of the reconstructed oocytes could mature in vitro and 7.1-9.4% of the oocytes developed to blastocyst stage after intracytoplasmic sperm injection (ICSI). Transfer of 93 fertilized eggs reconstructed via GV transfer into six recipients resulted in two live offspring. Results of this experiment indicate that GV transfer can potentially become a new approach in treatment of infertility because of advanced maternal age.

Effects of nicotine and cotinine on porcine arterial endothelial cell function

BACKGROUND. There has been a significant amount of research on the effects of nicotine on vascular biology; however, little is known about the effects of cotinine, the metabolic product of nicotine. This study used a novel vascular perfusion system to study the effects of nicotine and cotinine on the vascular endothelial cell function.

METHODS

Porcine common carotid arteries were cultured in a novel vascular perfusion system with nicotine or cotinine or as controls. After 24 h, vessels were precontracted with norepinephrine and subsequently relaxed with acetylcholine. Vessel diameters were recorded and analyzed. After culture, samples were taken for en face, immunohistochemistry, and RT-PCR for eNOS. Porcine coronary arteries were incubated as controls or with nicotine or cotinine and tested on a myograph system to measure contraction and relaxation.

RESULTS

Porcine carotid arteries treated with nicotine and cotinine showed a 27.2% and a 41.2% reduction in endothelial-dependent relaxation, respectively, as compared to control vessels (P<0.05). Rings of coronary arteries treated with nicotine relaxed similarly to control rings while cotinine-treated rings failed to relax to endothelial-dependent stimulation. RT-PCR for eNOS mRNA showed a 23. 2 and a 24.1% reduction in eNOS expression for nicotine- and cotinine-treated vessels, respectively (P<0.01). Additionally, immunohistochemical staining for eNOS showed less dense staining on nicotine- and cotinine-treated vessels as compared to controls. En face preparations showed normal endothelial cell morphology in all groups, but cell density decreased slightly in vessels treated with nicotine and cotinine.

CONCLUSION

These results indicate that cotinine may have even more effect on the impairment of endothelial-dependent vasorelaxation than nicotine for the regulation of vessel tone in porcine carotid and coronary arteries.

Protective effect of gypenosides on DNA and RNA of rat neurons in cerebral ischemia-reperfusion injury

AIM

To observe the protective effect of gypenosides (GP) on the neurons of hippocampus, cerebral cortex, corpus striatum, and dentate gyrus in cerebral ischemia-reperfusion injury of rats.

METHODS

Modified 4-vessel occlusion (4-VO) method was used to establish the model of acute global ischemia. The acridine orange (AO) staining method was used to observe the DNA and RNA contents of cerebral ischemia-reperfusion injury model in the areas.

RESULTS

The fluorescent intensity (reflecting DNA and RNA contents) of the DNA and RNA in the areas of cerebral ischemia-reperfusion injury was markedly abated compared with the normal control group. In the group of ig GP (100 mg/kg) it was enhanced compared with the model group and was the same as the normal control group.

CONCLUSION

The injury of the DNA and RNA in the areas of ischemia-reperfusion model was decreased by GP.

Validation of a Monte Carlo dose calculation tool for radiotherapy treatment planning

A new EGS4/PRESTA Monte Carlo user code, MCDOSE, has been developed as a routine dose calculation tool for radiotherapy treatment planning. It is suitable for both conventional and intensity modulated radiation therapy. Two important features of MCDOSE are the inclusion of beam modifiers in the patient simulation and the implementation of several variance reduction techniques. Before this tool can be used reliably for clinical dose calculation, it must be properly validated. The validation for beam modifiers has been performed by comparing the dose distributions calculated by MCDOSE and the well-benchmarked EGS4 user codes BEAM and DOSXYZ. Various beam modifiers were simulated. Good agreement in the dose distributions was observed. The differences in electron cutout factors between the results of MCDOSE and measurements were within 2%. The accuracy of MCDOSE with various variance reduction techniques was tested by comparing the dose distributions in different inhomogeneous phantoms with those calculated by DOSXYZ without variance reduction. The agreement was within 1.0%. Our results demonstrate that MCDOSE is accurate and efficient for routine dose calculation in radiotherapy treatment planning, with or without beam modifiers.

Monte Carlo verification of IMRT dose distributions from a commercial treatment planning optimization system

The purpose of this work was to use Monte Carlo simulations to verify the accuracy of the dose distributions from a commercial treatment planning optimization system (Corvus, Nomos Corp., Sewickley, PA) for intensity-modulated radiotherapy (IMRT). A Monte Carlo treatment planning system has been implemented clinically to improve and verify the accuracy of radiotherapy dose calculations. Further modifications to the system were made to compute the dose in a patient for multiple fixed-gantry IMRT fields. The dose distributions in the experimental phantoms and in the patients were calculated and used to verify the optimized treatment plans generated by the Corvus system. The Monte Carlo calculated IMRT dose distributions agreed with the measurements to within 2% of the maximum dose for all the beam energies and field sizes for both the homogeneous and heterogeneous phantoms. The dose distributions predicted by the Corvus system, which employs a finite-size pencil beam (FSPB) algorithm, agreed with the Monte Carlo simulations and measurements to within 4% in a cylindrical water phantom with various hypothetical target shapes. Discrepancies of more than 5% (relative to the prescribed target dose) in the target region and over 20% in the critical structures were found in some IMRT patient calculations. The FSPB algorithm as implemented in the Corvus system is adequate for homogeneous phantoms (such as prostate) but may result in significant under or over-estimation of the dose in some cases involving heterogeneities such as the air-tissue, lung-tissue and tissue-bone interfaces.

Expression of GABA transporters on bullfrog retinal Müller cells

gamma-Aminobutyric acid (GABA) transporters (GATs) are involved in regulating GABAergic transmission through the high-affinity uptake and release of GABA. In the present work, the expression of different subtypes of GATs (GAT-1, GAT-2, and GAT-3) on Müller cells was investigated both immunocytochemically and electrophysiologically in the bullfrog retina. Double-labeling experiments of glial fibrillary acidic protein (GFAP), a specific marker for Müller cells, and GATs showed that the somata, major processes, endfeet, and even branchlets of almost all Müller cells strongly expressed GAT-1 on the membrane, whereas the main trunks and endfeet of about 80-90% Müller cells were moderately GAT-2 labeled. No GAT-3 immunoreactivity was observed in Müller cells. Meanwhile, using the whole-cell recording technique, GAT-mediated currents were recorded from Müller cells in the retinal slice preparation, and they were reversibly blocked by removal of extracellular Na(+) and spread more or less evenly over the surface of these cells. Furthermore, the GATs on the Müller cells were sensitive to both nipecotic acid and beta-alanine, GABA uptake blockers. Taken together, the complementary immunocytochemical and electrophysiological results suggest that bullfrog Müller cells express functional GAT-1 and GAT-2, which may regulate GABAergic transmission by either taking up or releasing GABA, or both.

Energy- and intensity-modulated electron beams for radiotherapy

This work investigates the feasibility of optimizing energy- and intensity-modulated electron beams for radiation therapy. A multileaf collimator (MLC) specially designed for modulated electron radiotherapy (MERT) was investigated both experimentally and by Monte Carlo simulations. An inverse-planning system based on Monte Carlo dose calculations was developed to optimize electron beam energy and intensity to achieve dose conformity for target volumes near the surface. The results showed that an MLC with 5 mm leaf widths could produce complex field shapes for MERT. Electron intra- and inter-leaf leakage had negligible effects on the dose distributions delivered with the MLC, even at shallow depths. Focused leaf ends reduced the electron scattering contributions to the dose compared with straight leaf ends. As anticipated, moving the MLC position toward the patient surface reduced the penumbra significantly. There were significant differences in the beamlet distributions calculated by an analytic 3-D pencil beam algorithm and the Monte Carlo method. The Monte Carlo calculated beamlet distributions were essential to the accuracy of the MERT dose distribution in cases involving large air gaps, oblique incidence and heterogeneous treatment targets (at the tissue-bone and bone-lung interfaces). To demonstrate the potential of MERT for target dose coverage and normal tissue sparing for treatment of superficial targets, treatment plans for a hypothetical treatment were compared using photon beams and MERT.

[A survey on botanical origins of drug Xue Lianhua produced in China]

OBJECTIVE

Based on an to investigation and identification of commercial samples to find out the original species and resources of Xue Lianhua.

METHOD

Botanical and macroscopical identification.

RESULT

The main original species of the plant are Saussurea involucrata, S. medusa, S. gossypiphora, S. polylada, S. laniceps, S. tridactyla, S. gnaphaloides, S. kingii, S. obvallata, S. tangutica, S. globosa, S. longifolia, Soroseris erysimoides, So. glomerata and So. umbrella.

CONCLUSION

The flower and stem of S. involucrata and S. polylada and the whole herb of S. medusa and S. gossypiphora are used as Xue Lianhua in most areas of China.

A spinal cord slice preparation for analyzing synaptic responses to stimulation of pelvic and pudendal nerves in mature rats

The dorsal commissural nucleus (DCN) in the lumbosacral spinal cord (L6-S1) receives primary afferent fibers from both pelvic and pudendal nerves in rats. However, the physiological and pharmacological properties of synaptic responses of the DCN neurons to stimulation of those nerves remain unclear. We have developed a longitudinal spinal cord (L6-S1) slice preparation from mature rats that retained both nerves attached. Blind whole-cell recordings were made from the DCN neurons in this preparation. In most neurons, mono- and/or poly-synaptic fast excitatory postsynaptic potentials (EPSPs) were evoked by electrical stimulation of either the pelvic or pudendal nerve. These EPSPs were mediated by activation of Abeta/Adelta and/or C fibers (conduction velocities, 0.5-17.3 m/s), and were abolished by CNQX. Fast EPSPs elicited by either pelvic or pudendal nerve stimulation were occasionally accompanied by bicuculline- and strychnine-sensitive IPSPs. In one-third of the neurons tested, mono- and/or poly-synaptic EPSPs were elicited by the stimulation of both the pelvic and pudendal nerves, indicating convergence of the visceral and somatic primary afferent inputs from the pelvic region onto the DCN neurons. The preparation is applicable to study the mechanism of the integration of the visceral and somatic inputs in the spinal cord.

5-HT potentiates GABA- and glycine-activated chloride currents on the same neurons in rat spinal cord

The electrophysiological and pharmacological properties of GABA- and glycine (Gly)-induced responses were investigated in neurons acutely dissociated from the rat sacral dorsal commissural nucleus (SDCN) using the nystatin perforated patch recording configuration under voltage-clamp conditions. At a holding potential of -40 mV, the currents evoked by GABA and Gly increased in a sigmoidal fashion with increasing agonist concentration. The reversal potentials of I(GABA)and I(Gly) were close to the Cl- equilibrium potential. Bicuculline (BIC) and strychnine (STR) suppressed I(GABA) and I(Gly) in a concentration-dependent manner, although they have different affinities for GABA and Gly. 5-HT potentiated both I(GABA) and I(Gly) via intracellular protein kinase C on the same neurons. The results indicated that the acutely dissociated SDCN neurons responded to both exogenous GABA and Gly, which activated GABA(A) and STR-sensitive Gly receptors, respectively, and 5-HT may produce spinal antinociception through postsynaptic potentiation of I(GABA) and I(Gly) when they are coreleased; GABA and Gly may act as cotransmitters implicated in the control of spinal nociceptive signal processing in the mammalian spinal cord.

[Study on early repair of destructive hand injury and reconstruction of hand function]

OBJECTIVE

To investigate a clinical method in repairing destructive hand injury and reconstructing hand function in early stage.

METHODS

From January 1990 to June 1999, composite tissue transplantation was used to repair destructive hand damage and reconstruct hand function with vascular anastomosis in emergency (33 cases) or subemergency (126 cases). For the radial damage, combined flaps with toes was used to treat cicatricial contracture of thumb-web space. Opposing function of thumb was reconstructed by combined transplantation of short extensor muscle of great toe, short extensor muscle of toes or short abductor muscle of great toe in the same time of freeing the second toe. For no or deficient anastomosing vessels in donor site, "Y"--shaped reversal vein, anterograde bridging, or branches bridging of host vessels were applied.

RESULTS

All of tissue transplantation were survived, including combined tissue transplantation in 51 cases, composite tissue transplantation in 4 cases, tissue transplantation after replantation of severed wrist and finger in 4 cases, there were no infection or necrosis in all cases, and hand function recovered well.

CONCLUSION

It is an ideal procedure to repair destructive hand injury and reconstruct hand function by combined or composite tissue transplantation with vascular anastomosis in emergency or subemergency.

Determination of sulfonamides in swine meat by immunoaffinity chromatography

A procedure was developed for the preparation of anti-sulfonamide (SA) group-specific antibodies and immunosorbents. Sulfonamide haptens and conjugates were synthesized by building spacer arms on an N1 group of 4-aminobenzensulfonamide. The anti-SA group-specific antibodies and immunosorbents were prepared successfully. After extraction with methanol-water (8 + 2), sulfamonomethoxine, sulfadimethoxine, and sulfaquinoxaline were cleaned up on immunoaffinity columns and determined by reversed-phase liquid chromatography with UV detection at 270 nm. The recoveries from fortified swine meat (10-100 microg/kg) ranged from 70.8 to 94.1%, with coefficients of variation of 3.4-12.9%. Limits of detection were 1-2 microg/kg.

Clinical auscultation skills in pediatric residents

OBJECTIVE

The aim of this study is to determine the level of clinical auscultation skills in pediatric residents at Duke University Medical Center.

METHODS

Forty-seven residents from pediatrics and joint medicine/pediatrics training programs at Duke University Medical Center were enrolled in this study. They were asked to examine the cardiovascular patient simulator, Harvey, and report their findings. Five common conditions seen in the pediatric population were presented: ventricular septal defect, atrial septal defect, pulmonary valve stenosis, combined aortic valve stenosis and insufficiency, and innocent systolic ejection murmur. The responses were scored by the number of features and diagnoses accurately reported. Five pediatric cardiologists and cardiologists in training were also asked to participate in a manner similar to the trainees.

RESULTS

The mean score of features identified for the resident group was 11.4 +/- 2.6 of a possible 19. The diagnostic accuracy was 33%. There was no significant difference between residents by year of training or by type of residency program, although there was a trend toward improved performance with more training. The difference in performance between the pediatric cardiology group and the residents group was striking. The condition that was most frequently misdiagnosed was the innocent systolic ejection murmur.

CONCLUSIONS

The clinical auscultation skills of pediatric residents in this study were suboptimal. There was a trend toward improvement as training progressed, although not statistically significant. These skills are likely to improve further with increased exposure to patients with cardiovascular disease especially in the ambulatory care setting.

Genuine saddle point and nucleation potential for binary systems

A generalized nucleation potential is constructed for binary systems. The potential consists of the reversible work of cluster formation plus additional terms arising from various kinetic effects. We show that the major nucleation flux passes through the saddle point (termed the genuine saddle point) of this generalized nucleation potential. The generalized nucleation potential reduces to the kinetic potential of a unary system when one component vanishes. The genuine saddle point concept provides a convenient way to identify systems and conditions for which the ridge crossing phenomenon occurs. Our theory agrees approximately with exact numerical results.