Picosecond Spin Current Generation from Vicinal Metal-Antiferromagnetic Insulator Interfaces.

We report the picosecond spin current generation from the interface between a heavy metal and a vicinal antiferromagnet insulator Cr_{2}O_{3} by laser pulses at room temperature and zero magnetic field. It is converted into a detectable terahertz emission in the heavy metal via the inverse spin Hall effect. The vicinal interfaces are apparently the source of the picosecond spin current, as evidenced by the proportional terahertz signals to the vicinal angle. We attribute the origin of the spin current to the transient magnetic moment generated by an interfacial nonlinear magnetic-dipole difference-frequency generation. We propose a model based on the in-plane inversion symmetry breaking to quantitatively explain the terahertz intensity with respect to the angles of the laser polarization and the film azimuth. Our work opens new opportunities in antiferromagnetic and ultrafast spintronics by considering symmetry breaking.

[Association between volatile organic compounds and mortality risk of stroke].

Objective: To investigate the effect of volatile organic compounds (VOCs) exposure in the atmosphere on the risk of daily death from stroke in Guangzhou. Methods: Daily average concentrations of twelve atmospheric VOCs, meteorological factors, and daily deaths for stroke and its subtypes (including ischemic and hemorrhagic stroke) in Guangzhou from 2020 to 2021 were collected. The time-series Poisson generalized additive model was established to analyze the relationship between daily average concentrations of atmospheric VOCs and daily mortality from a stroke on different lag days. The season, gender, and age group further performed stratification analysis. Results: Toluene and n-pentane were associated with a higher mortality risk from stroke and its subtypes. For each interquartile range (IQR) increment in toluene concentration at lag0- 1 days, the RRs for mortality from stroke and hemorrhagic stroke were 1.060 (95%CI: 1.036-1.085) and 1.071 (95%CI: 1.030-1.113), respectively. For each IQR increment in n-pentane concentration, the RR for mortality from ischemic stroke was 1.064 (95%CI: 1.030-1.099). The effect estimates of VOCs may be higher during the cold season and among women and people aged ≥75 years. For each IQR increment in toluene concentration, the RRs for mortality risk of stroke in the cold season and women were 1.099 (95%CI: 1.056-1.143) and 1.085 (95%CI: 1.050-1.120), respectively. For n-pentane, the RR for death risk of stroke in people aged ≥75 years old was 1.072 (95%CI: 1.036-1.109). Results of sensitivity analysis showed that the effect estimates fluctuated less when PM2.5 and O3 were separately introduced for the two-pollutant model, as well as changing the degrees of freedom for covariates. Conclusions: This study suggests that VOCs may be an independent risk factor for daily mortality from stroke. Moreover, Toluene presented the most significant health impact.

[Prognostic value of a predictive model comprising preoperative inflammatory response and nutritional indexes in patients with gastric cancer].

Objective: To investigate the prognostic value of preoperative inflammatory and nutritional condition detection in the postoperative survival, and establish a prognostic model for predicting the survival of patients with gastric cancer. Methods: The clinicopathological data of 1123 patients with gastric cancer who had undergone radical gastrectomy in Tianjin Medical University Cancer Institute & Hospital from January 2005 to December 2014 were retrospectively analyzed. Patients with history of other malignancy, with history of gastrectomy, who had received preoperative treatment, who died during the initial hospital stay or first postoperative month, and missing clinical and pathological information were excluded. Cox univariate and multivariate analyses were used to identify independent clinicopathological factors associated with the survival of these gastric cancer patients. Cox univariate analysis was used to identify preoperative inflammatory and nutritional indexes related to the survival of patients with gastric cancer after radical gastrectomy. Moreover, the Cox proportional regression model for multivariate survival analysis (forward stepwise regression method based on maximum likelihood estimation) was used. The independent clinicopathological factors that affect survival were incorporated into the following three new prognostic models: (1) an inflammatory model: significant preoperative inflammatory indexes identified through clinical and univariate analysis; (2) a nutritional model: significant preoperative nutritional indexes identified through clinical and univariate analysis; and (3) combined inflammatory/nutritional model: significant preoperative inflammatory and nutritional indexes identified through clinical and univariate analysis. A model that comprised only pT and pN stages in tumor TNM staging was used as a control model. The integrated area under the receiver operating characteristic curve (iAUC) and C-index were used to evaluate the discrimination of the model. Model fitting was evaluated by Akaike information criterion analysis. Calibration curves were used to assess agreement between the predicted probabilities and actual probabilities at 3-year or 5-year overall survival (OS). Results: The study cohort comprised 1 123 patients with gastric cancer. The mean age was 58.9±11.6 years, and 783 were males. According to univariate analysis, age, surgical procedure, extent of lymph node dissection, tumor location, maximum tumor size, number of examined lymph nodes, pT stage, pN stage, and nerve invasion were associated with 5-year OS after radical gastrectomy for gastric cancer (all P<0.050). Multivariate analysis further identified age (HR: 1.18, 95%CI: 1.03-1.36, P=0.019), maximum tumor size (HR: 1.19, 95%CI: 1.03-1.38, P=0.022), number of examined lymph nodes (HR: 0.79, 95%CI: 0.68-0.92, P=0.003), pT stage (HR: 1.40, 95%CI: 1.26-1.55, P<0.001) and pN stage (HR: 1.28, 95%CI: 1.21-1.35, P<0.001) as independent prognostic factors for OS of gastric cancer patients. Additionally, according to univariate survival analysis, the preoperative inflammatory markers of neutrophil count, percentage of neutrophils, neutrophil/lymphocyte ratio, platelet/neutrophil ratio and preoperative nutritional indicators of serum albumin and body mass index were potential prognostic factors for gastric cancer (all P<0.05). On the basis of the above results, three models for prediction of prognosis were constructed. Variables included in the three models are as follows. (1) Inflammatory model: age, maximum tumor size, number of examined lymph nodes, pT stage, pN stage, percentage of neutrophils, and neutrophil-lymphocyte ratio; (2) nutritional model: age, maximum tumor size, number of examined lymph nodes, pT stage, pN stage, and serum albumin; and (3) combined inflammatory/nutritional model: age, maximum tumor size, number of examined lymph nodes, pT stage, pN stage, percentage of neutrophils, neutrophil-lymphocyte ratio, and serum albumin. We found that the predictive accuracy of the combined inflammatory/nutritional model, which incorporates both inflammatory indicators and nutrition indicators (iAUC: 0.676, 95% CI: 0.650-0.719, C-index: 0.698),was superior to that of the inflammation model (iAUC: 0.662, 95% CI: 0.673-0.706;C-index: 0.675), nutritional model (iAUC: 0.666, 95% CI: 0.642-0.698, C-index: 0.672), and TNM staging control model (iAUC: 0.676, 95% CI: 0.650-0.719, C-index: 0.658). Furthermore, the combined inflammatory/nutritional model had better fitting performance (AIC: 10 762) than the inflammatory model (AIC: 10 834), nutritional model (AIC: 10 810), and TNM staging control model (AIC: 10 974). Conclusions: Preoperative percentage of neutrophils, NLR, and BMI have predictive value for the prognosis of gastric cancer patients. The inflammatory / nutritional model can be used to predict the survival and prognosis of gastric cancer patients on an individualized basis.

Topological spin and valley pumping in silicene.

We propose to realize adiabatic topological spin and valley pumping by using silicene, subject to the modulation of an in-plane ac electric field with amplitude Ey and a vertical electric field consisting of an electrostatic component and an ac component with amplitudes and . By tuning and , topological valley pumping or spin-valley pumping can be achieved. The low-noise valley and spin currents generated can be useful in valleytronic and spintronic applications. Our work also demonstrates that bulk topological spin or valley pumping is a general characteristic effect of two-dimensional topological insulators, irrelevant to the edge state physics.

Low level of low-density lipoprotein cholesterol is related with increased hemorrhagic transformation after acute ischemic cerebral infarction.

OBJECTIVE: The prevalence of hemorrhagic transformation (HT) after acute ischemic infarction varies greatly. Risk factors of HT include ageing, severity of stroke, baseline hypertension, high NIH Stroke Scale (NIHSS) scores, hyperglycemia and cardioembolic infarction and low levels of low-density lipoprotein (LDL). We investigated the relationship between LDL, lipid profile and HT after acute ischemic infarction and suggested precautions for HT management. PATIENTS AND METHODS: Three hundred and forty-eight patients with acute infarction were included in the study. Fasting lipid profile was examined on the next morning following hospitalization. Either MRI GRE-T2*WI or CT was performed, one week after hospitalization to detect any cerebral microbleed (CMB) and hemorrhagic transformation. The lipid profiles examined included total cholesterol (TCH), triglyceride (TG), LDL and high-density lipoprotein (HDL). RESULTS: Among all the patients, HT was noted in 35 patients and non-HT in 313. As compared with non-HT group, HT group had lower levels of TCH, HDL and LDL, lower rates of leukoaraiosis and CMB, but higher scores of NIHSS, higher rates of diabetes mellitus, atrial fibrillation and urokinase thrombolysis. The multivariate binary logistic regression showed that cardioembolic infarction, infarction with undetermined etiology, high scores of NIHSS and diabetes were the risk factors of HT, while the protective factor was LDL (OR=0.654, 95% CI: 0.430-0.996, p=0.048). CONCLUSIONS: Low level of LDL is likely associated with increased HT after acute ischemic infarct, so for those patients with low level of LDL, high scores of NIHSS and cardioembolic infarction at admission, aggressive lipid- lowering treatment should be prescribed cautiously to prevent the incidence of HT.

Clinical study of seven patients with special syndrome of post-epileptic dysfunction persisting over 24 hours.

OBJECTIVE: Todd's paralysis is the most common complication after epileptic seizures, especially status epilepticus, but other disabilities deriving from the postictal state are poorly understood. There is relatively little information on the underlying parameters that affect clinical features of post-epileptic dysfunction. The aim of this paper is to investigate clinical features of special post-epileptic dysfunction persisting over 24 hours. PATIENTS AND METHODS: Seven patients with special syndromes of post-epileptic dysfunction were retrospectively analyzed and the related literature was reviewed. RESULTS: Six patients with post-epileptic dysfunction experienced status epilepticus. Of the seven patients, six had underlying structural brain lesions. Post-epileptic dysfunction has different syndromes, including post-epileptic paralysis, post-epileptic aphasia, cognitive disorder, gaze palsy and hemianopsia. The duration of the dysfunction in these patients lasted from 2 days to 3 months. CONCLUSIONS: The great majority of patients with post-epileptic dysfunction experience status epilepticus and have underlying structural brain lesions. Post-epileptic dysfunction includes various syndromes and can last from several days to 3 months with a good prognosis.

First Report of Fusarium oxysporum and F. solani Causing Fusarium Dry Rot of Carrot in China.

Carrot (Daucus carota L.) is an economically important vegetable crop in China. In August 2008, a disease was observed on carrot in Inner Mongolia. The symptoms appeared as dry rot lesions on root surface, expressing light brown cankers with defined rounded or irregular shapes (1,3). The average disease incidence was up to 80% in Tuo Ke Tuo County. The disease has been a serious problem in these two counties since then, especially where consecutive carrot cropping was practiced. Carrot roots with typical dry rot symptoms were washed with tap water. Root tissues near the margin of necrotic lesions were excised, surface sterilized with 1% NaOCl for 3 min, and rinsed with sterile distilled water three times. The disinfected tissue was placed on potato dextrose agar (PDA) in a petri dish. Plates were incubated at 25 ± 1°C in the dark for 4 days. Fusarium single spore isolates were obtained from characteristic colonies (1). Three isolates (CF1, CF2, and CF3) were used for further study. The isolates were identified as Fusarium spp. on the basis of microscopic morphology on PDA. CF1 produced pink pigment, abundant falciform macroconidia of 14.7 to 38.2 × 4.5 to 5.7 µm with 2 to 3 septates, and elliptic microconidia of 7.5 to 15.1 × 3.3 to 5.4 µm with none or one septate. CF2 and CF3 produced light blue pigment, abundant falciform macroconidia of 16.4 to 34.4 × 4.0 to 6.1 µm with 2 to 3 septates, and elliptic microconidia of 6.7 to 10.7 × 3.0 to 4.9 µm with none or one septate. They were further identified and confirmed by PCR. The PCR involved amplifying the internal transcribed spacer (ITS) region of ribosomal DNA using genomic DNA as the template with universal primers ITS1 and ITS4 (2). The PCR products were sequenced. BLAST analysis of these sequences against the GenBank database determined the taxonomy of the isolates. The sequence of CF1 was 99% identical to F. oxysporum (Accession No. KC594035); sequences of CF2 and CF3 were 99% identical to F. solani (KC215123). To confirm the pathogenicity of the isolates, mature carrot roots (cv. Hong Ying 2) were inoculated with mycelial plugs (5 mm in diameter) cut from the margin of actively growing colonies on PDA plates. One mycelial plug was placed on each carrot root, with the mycelial side facing the root. PDA plugs were used for controls. Each treatment had five replicates. The inoculated roots were incubated in a humid chamber (90% RH) at 25°C. Four days after incubation, mycelia of the isolates developed and covered most of the surface of carrot roots, and brown rot lesions were observed on all inoculated roots, while the controls remained symptomless. This experiment was repeated. In another trial, carrot seeds (cv. Hong Ying 2) were sown in sterilized soil in pots (30 × 25 cm opening) with 15 seeds per pot. The soil was infested with either CF1, CF2, or CF3 by adding spore suspension to make the final concentration of 1 × 104 CFU/g soil. Plants grown in non-infested soil served as controls. There were three replicates per treatment. All the treated pots were placed in a field. After 13 weeks, the same symptoms of dry rot were observed as previously described. No symptoms were observed on the control plants. The trial was repeated. Symptomatic tissues from the inoculated roots were sampled and the pathogen was re-isolated, and identified using PCR. To our knowledge, this is the first report of F. oxysporum and F. solani causing dry rot of carrot in China. References: (1) H. Abe et al. Annual Report of the Society of Plant Protection of North Japan, 48:106-108, 1997. (2) X. Lu. Plant Dis. 97:991, 2013. (3) A. F. Sherf and A. MacNab. Pages 138-139 in: Vegetable Diseases and Their Control. John Wiley & Sons, Inc., 1986.

Electron entanglement detected by quantum spin Hall systems.

We propose a promising electron entanglement detector consisting of two quantum spin Hall systems weakly coupled to a superconductor. The detection of electron spins along various polarization directions, which is a prerequisite for testing Bell's inequality on solid state spins, can be achieved in an all-electrical-controlled manner utilizing the helical edge states. It is found that the violation of Bell's inequality exists in a large range of the tunneling parameters, which can be realized in mercury telluride quantum wells.

Is spinal anaesthesia at L2-L3 interspace safe in disorders of the vertebral column? A magnetic resonance imaging study.

BACKGROUND: The varying point at which the spinal cord terminates in the lumbar spinal canal may affect the incidence of spinal cord injuries associated with needle insertion for spinal anaesthesia, especially in patients with vertebral body or intervertebral disc disease. This is a complication which has been frequently reported when spinal needle insertion was performed at higher lumbar spinal levels. METHODS: We retrospectively reviewed magnetic resonance images of the spine in 1047 Chinese patients to determine the conus medullaris terminus (CMT) in patients with and without vertebral disorders. Patients with tumours in and around the spine and those with congenital spinal anomalies were excluded from the study. Patients with mixed vertebral disorders were also excluded. RESULTS: Our data demonstrate that patients with thoracic vertebral compression fractures had lower ending points of the CMT than those without (P<0.05), while patients with lumbar compression fractures did not demonstrate such a correlation. With regard to this difference, females were significantly at higher risk for a lower CMT than males. Conversely, lumbar disc disorders such as intervertebral disc extrusion, herniation, or bulging did not have any significant influence on the level of CMT. Moreover, patients with spondylolisthesis or scoliosis did not demonstrate an abnormal CMT location. CONCLUSIONS: When performing spinal anaesthesia, anaesthesiologists should be aware of potential differences of the CMT location, particularly in female patients with thoracic vertebral compression fractures, who may have a lower CMT than normal, extending to the level of L2. Performing spinal anaesthesia at the L2-L3 interspace would seem to be ill-advised in this patient population.

Two-photon microscopy of deep intravital tissues and its merits in clinical research.

Multiphoton excitation laser scanning microscopy, relying on the simultaneous absorption of two or more photons by a molecule, is one of the most exciting recent developments in biomedical imaging. Thanks to its superior imaging capability of deeper tissue penetration and efficient light detection, this system becomes more and more an inspiring tool for intravital bulk tissue imaging. Two-photon excitation microscopy including 2-photon fluorescence and second harmonic generated signal microscopy is the most common multiphoton microscopic application. In the present review we take diverse ocular tissues as intravital samples to demonstrate the advantages of this approach. Experiments with registration of intracellular 2-photon fluorescence and extracellular collagen second harmonic generated signal microscopy in native ocular tissues are focused. Data show that the in-tandem combination of 2-photon fluorescence and second harmonic generated signal microscopy as two-modality microscopy allows for in situ co-localization imaging of various microstructural components in the whole-mount deep intravital tissues. New applications and recent developments of this high technology in clinical studies such as 2-photon-controlled drug release, in vivo drug screening and administration in skin and kidney, as well as its uses in tumourous tissues such as melanoma and glioma, in diseased lung, brain and heart are additionally reviewed. Intrinsic emission two-modal 2-photon microscopy/tomography, acting as an efficient and sensitive non-injurious imaging approach featured by high contrast and subcellular spatial resolution, has been proved to be a promising tool for intravital deep tissue imaging and clinical studies. Given the level of its performance, we believe that the non-linear optical imaging technique has tremendous potentials to find more applications in biomedical fundamental and clinical research in the near future.

Outcome in relation to numbers of nodes harvested in lymph node-positive gastric cancer.

AIMS: We conducted a retrospective case-control study to compare the prognostic differences of lymph node-positive gastric cancer patients between dissected lymph nodes (DLNs) <15 group and DLNs > or =15 group. METHODS: A retrospective study of 323 lymph node-positive gastric patients who underwent potentially curative resection for gastric cancer was analyzed to identify the prognostic differences between DLNs <15 group and DLNs > or =15 group. Of these patients, 49 patients with <15 DLNs were matched with 147 patients with > or =15 DLNs according to gender, age, location of primary tumor, and type of gastrectomy. RESULTS: Patients with n1 lymph node metastasis (according to JCGC), serosal involvement, ratio of positive lymph nodes less than 25%, or without adjuvant chemotherapy in > or =15 DLN group had comparatively longer median survival than patients with homologous clinicopathologic variables in <15 DLN group, respectively. Patients with n1 stage lymph node metastasis, serosal involvement, non-intestinal Lauren classification, or without adjuvant chemotherapy in <15 DLN group had higher recurrence rate than patients with homologous clinicopathologic variables in > or =15 DLN group, respectively. In addition, we demonstrated that patients with more than n1 stage lymph node metastasis in <15 DLN group had higher rate of peritoneal dissemination than those with more than n1 lymph node metastasis in > or =15 DLN group. CONCLUSIONS: DNL > or =15 was an important factor to improve the prognosis of lymph node-positive gastric cancer patients after potential curative resection.

Laurane-derived sesquiterpenes from the marine red alga Laurencia tristicha (Rhodomelaceae).

Two new stereoisomers of laurane-derived brominated sesquiterpenes, 4-bromolaur-11-en-1,10alpha-diol (1) and 4-bromolaur-11-en-1,10beta-diol (2), one new natural product, laur-11-en-1,10alpha-diol (3), together with 11 known compounds (4-14) were isolated and identified from the organic extract of the marine red alga Laurencia tristicha. Their structures and relative stereochemistry were established by analysis of mass and NMR spectroscopic techniques.

[Determination of volatile organic compounds in atmospheric environment].

It is well known that volatile organic compounds (VOCs) are the main photochemical pollutants and ozone precursors of the photochemical smog. Investigation of photochemical pollution in the ambient air must focus on VOCs, but the concentration of VOCs in ambient air is in a very low level (10(-9)-10(-12), volume fraction), so there are difficulties in the determination of VOCs. In this work, based on the TO14A and TO15 methods recommended by the Environmental Protection Agency of United States, an improved method for the determination of fifty-six VOCs, mainly O3 precursors, in atmospheric environment was developed. Operating conditions of VOCs preconcentrator, gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) were optimized. Air sample was first frozen by liquid nitrogen, and then H2O and CO2 were eliminated in the VOCs preconcentrator. The preconcentrated VOCs sample was injected to GC and detected by MS or hydrogen flame ionization detector (FID). The C2-C10 hydrocarbons were separated effectively in capillary columns under the high concentration of CO2. The detection limits were 0.1 microgram.m-3 and the relative standard deviations were in the range from 2.57% to 9.82%. This method has been used for the determination of VOCs in real samples. The results were satisfactory.

Aglacins A-D, first representatives of a new class of aryltetralin cyclic ether lignans from Aglaia cordata.

Four new metabolites, aglacins A-D (1-4), were identified from the methanol extract of the stem bark of Aglaia cordata. These compounds represent a new class of aryltetralin cyclic ether lignan. The structure of aglacin A (1) including the absolute configuration was elucidated by interpretation of spectral data, X-ray crystal structure determination, and employing the modified Mosher's method. In addition, three other derivatives, aglacins B-D (2-4), were isolated and identified by spectral means.

Chemical constituents of two Chinese Magnoliaceae plants, Tsoongiodendron odorum and Manglietiastrum sinicum, and their inhibition of platelet aggregation.

Phytochemical investigations of Tsoongiodendron odorum and Manglietiastrum sinicum, both Magnoliaceae, led to the isolation of twenty compounds in total. Among them, one was a new sesquiterpene, 11-O-oleoyl-beta-eudesmol (2), and another, 1-(3,4-dimethoxypheny)-4-(3,4-methylenedioxyphenyl)-2,3-dimethy lbutane (12) was isolated as a natural product for the first time. Moreover, 13C-NMR spectral data of isoguaiacin (16) are reported here for the first time. Structure elucidations for compounds reported here were mainly based on their spectral data. The ethanolic extracts of T. odorum and M. sinicum, and six pure compounds, 4(15)-eudesmen-11-ol (beta-eudesmol) (1), 1 beta-hydroxy-4(15),11(13)-eudesmadien-12,6 alpha-olide (reynosin) (3), 3,11(13)-eudesmadien-12,6 alpha-olide (alpha-cyclocostunolide) (5), erythro-1-(4-hydroxy-3-methoxyphenyl)-4-(3,4-methylenedioxyphenyl)-2,3- dimethylbutane (11), nectandrin-B (18), and syringaresinol (19), displayed considerable inhibition against platelet aggregation induced by AA, by ADP, or by PAF.

Rubupungenosides A and B, two novel triterpenoid saponin dimers from the aerial parts of Rubus pungens.

Two new triterpenoid saponin dimers, rubupungenosides A (1) and B (2), were isolated in their methylated forms 1a and 2a, respectively, from an ethanol extract of the aerial parts of Rubus pungens. The structures of 1a and 2a were established on the basis of spectroscopic and chemical methods.

Structural revision of four spiramine diterpenoid alkaloids from the roots of Spiraea japonica.

On the basis of detailed 1H-NMR 13C-NMR spectral analysis, especially by 2D NMR experiments (1H-1H COSY, HMQC, HMBC, and NOESY) as well as by chemical transformations. four isoatisine type diterpenoid alkaloids, spiramines P and Q, and U and T, have been reassigned as the 6beta hydroxyl and 6beta acetoxyl substituents, respectively, rather than the previously assigned 15alpha counterparts in our further studies on chemical constituents of the roots of Spiraea japonica var. acuta.

Local recurrence risk after skin-sparing and conventional mastectomy: a 6-year follow-up.

In this study, the records of all patients at the University of Texas M. D. Anderson Cancer Center with T1 or T2 breast cancer who were treated between March of 1986 and November of 1990 with mastectomy followed by immediate breast reconstruction were reviewed for the presence of recurrent disease. Patients with in situ disease were not included. Patients were included in the study if a local recurrence occurred (regardless of the length of follow-up) or if a follow-up of 6 years or longer could be obtained. Patients were grouped according to the use or nonuse of skin-sparing mastectomy, by tumor stage, and by nuclear grade of the tumor. The series included 154 patients, of whom 114 had skin-sparing mastectomies and 40 had nonskin-sparing mastectomies. The local recurrence rate in the skin-sparing mastectomy group was 7.0 percent, whereas in the nonskin-sparing mastectomy group it was 7.5 percent. The sample size in the nonskin-sparing mastectomy group was too small for meaningful statistical analysis, but the data suggest that there is no clinically important difference in recurrence rates between the two groups. We conclude that the use of skin-sparing technique for early breast cancer patients does not significantly increase the risk of tumor recurrence after mastectomy.

Fat necrosis in free and pedicled TRAM flaps.

One purported advantage of the free transverse rectus abdominis musculocutaneous (TRAM) flap for breast reconstruction is that, compared with the conventional TRAM flap, it has a better blood supply and therefore a lower incidence of fat necrosis. We tested this claim by reviewing the incidence of fat necrosis, both clinically and mammographically, in a group of 110 patients with 116 TRAM flap breast reconstructions who had undergone mammography of their reconstructed breasts. Of the 49 breasts reconstructed with free TRAM flaps, 4 (8.2 percent) had clinically evident fat necrosis, and 1 (2.0 percent) had fat necrosis that was detectable by mammography. Of the 67 breasts reconstructed with conventional TRAM flaps, 18 (26.9 percent) had clinically detectable fat necrosis, and 9 (13.4 percent) had fat necrosis that was detectable mammographically. Both of these differences were statistically significant (p = 0.0113 for clinical fat necrosis; p = 0.031 for mammographic fat necrosis). Fat necrosis was more common in patients who were obese or had a history of smoking, but neither association was statistically significant. We conclude that the use of the free TRAM flap reduces the incidence of fat necrosis in the reconstructed breast.

Drug-induced vasodilation: in vitro and in vivo study on the effects of lidocaine and papaverine on rabbit carotid artery.

Flap ischemia is often encountered during pedicled and free tissue transfer. In this study, the vascular effects of varying doses of lidocaine, papaverine, and a combination of the two agents were evaluated and compared in an in vitro and in vivo model in the rabbit carotid artery. In the in vitro study, 14 rings from the rabbit carotid artery were bathed in Krebs-Ringers solution and stretched progressively to an optimal tension of 3.7-4.2 grams. Their isometric contractile activity was measured. The specimens were precontracted with norepinephrine (1 microM), and a dose response curve was established by adding cumulatively either lidocaine (to 7 arterial rings) or papaverine (to 7 arterial rings) at increasing concentrations. In the in vivo study, microvascular anastomoses were performed bilaterally in the rabbit carotid artery in 30 animals using 9-0 nylon suture and standard microsurgical techniques. In each animal, one side was treated with heparinized sodium chloride and served as the control. The other side was treated blindly, during and after the anastomoses, with a topical application of 1 ml of either lidocaine 2% (n = 5), lidocaine 20% (n = 5), papaverine (30 mg/ml, n = 5), lidocaine 2% combined with papaverine (30 mg/ml, n = 5), or lidocaine 20% combined with papaverine (30 mg/ml, n = 5). For 30-60 minutes after the procedure, blood flow changes in the vessels were continuously monitored with a transonic doppler applied to both carotid arteries. The 20% lidocaine group was flushed with saline at the end of the first hour and monitored for an additional 60 minutes. Papaverine elicited a concentration-dependent relaxation of norepinephrine precontracted carotid artery rings in vitro. Lidocaine elicited a biphasic response, with low concentrations (10(-6)-10(-4) M) increasing the norepinephrine-induced contraction and high concentrations (10(-4)-10(-2) M) relieving this contraction. Microsurgical anastomosis produced a significant decrease of blood flow through the rabbit carotid artery as measured by the transonic doppler. Drug application did not alter the systemic blood pressure of the animals. Topical application of lidocaine 2% did not significantly change the blood flow after microvascular anastomosis. Topical application of lidocaine 20%, papaverine (30 mg/ml), or lidocaine (2% or 20%) combined with papaverine significantly increased the blood flow in the rabbit carotid artery. In the lidocaine 20% group, the blood flow remained significantly increased after the drug was flushed with heparinized saline solution. These results demonstrate that topical lidocaine 20%, papaverine, and lidocaine 2% or 20% combined with papaverine significantly increase blood flow in the rabbit carotid artery after microvascular anastomosis. The data confirm the use of papaverine and lidocaine 20%, alone or in combination, as spasmolytics during clinical microsurgery. This suggests that lidocaine 2% alone is not the ideal drug to relieve vascular constriction, and further studies on the clinical use of low concentrations of topical lidocaine in microsurgery is warranted.