Organization of horizontal axons in the inferior temporal cortex and primary visual cortex of the macaque monkey

We investigated the organization of horizontal connections at two distinct hierarchical levels in the ventral visual cortical pathway of the monkey, the inferior temporal (TE) and primary visual (V1) cortices. After injections of anterograde tracers into layers 2 and 3, clusters of terminals ('patches') of labeled horizontal collaterals in TE appeared at various distances up to 8 mm from the injection site, while in V1 clear patches were distributed only within 2 mm. The size and spacing of these patches in TE were larger and more irregular than those observed in V1. The labeling intensity of patches in V1 declined sharply with distance from the injection site. This tendency was less obvious in TE; a number of densely labeled patches existed at distant sites beyond weakly labeled patches. While injections into both areas resulted in an elongated pattern of patches, the anisotropy was greater in TE than in V1 for injections of a similar size. Dual tracer injections and larger-sized injections further revealed that the adjacent sites in TE had spatially distinct horizontal projections, compared to those in V1. These area-specific characteristics of the horizontal connections may contribute to the differences in visual information processing of TE and V1.     

Organization of nonprimary motor cortical inputs on pyramidal and nonpyramidal tract neurons of primary motor cortex: An electrophysiological study in the macaque monkey

To elucidate the functions of nonprimary motor cortical (nPMC) areas whose afferents synapse onto output neurons of the primary motor cortex (PMC), we examined the responses of pyramidal tract neurons (PTNs) and non-PTNs (nPTNs) to electrical stimulation in the three nPMCs, the supplementary motor area (SMA) and the dorsal and ventral divisions of the premotor cortex (PMd and PMv), with extracellular unit recording in alert monkeys. Typical responses of PTNs to nPMC stimulation were early orthodromic excitatory responses followed by inhibitory responses. Among 27 PTNs tested by constructing peri-stimulus time histograms, 19 (70.4%) showed inhibitory responses to stimulation in all of the nPMC areas. In contrast, 5/33 PTNs (15.2%) and 10/72 nPTNs (13.9%) showed excitatory responses to stimulation in all of the nPMCs. The inhibitory responses of PTNs were mediated by inhibitory interneurons, some of which may correspond to nPTNs in the superficial layers of the PMC. These interneurons probably possess widely extended axons and nonspecifically inhibit multiple PTNs in layer V. The excitatory and inhibitory influences, and the patterns of convergence of inputs from the nPMCs onto the PTNs, are important to understand motor control by the nPMC-PMC-spinal cord pathway.     

Separate processing dynamics for texture elements, boundaries and surfaces in primary visual cortex of the macaque monkey.

A visual scene is rapidly segmented into the regions that are occupied by different objects and background. Segmentation may be initiated from the detection of boundaries, followed by the filling-in of the surfaces between these boundaries to render them visible. Alternatively, segmentation may be based on grouping of surface elements that are similar, so that boundaries are (implicitly) identified as the borders between elements that are grouped into objects. Here, we present recordings from awake monkey primary visual cortex that show that in late (>80 ms) components of the neural responses a correlate of boundary formation is expressed, followed by a filling-in (also called colouring) between the edges. These data favour a model of segmentation where boundary formation initiates surface filling-in.     

A comparative study of shape representation in macaque visual areas v2 and v4

We compared aspects of shape representation in extrastriate visual areas V2 and V4, which are both implicated in shape processing and belong to different hierarchical levels. We recorded responses of cells in awake, fixating monkeys to matched sets of contour and grating stimuli of low or intermediate complexity. These included simple stimuli (bars and sinusoids) and more complex stimuli (angles, intersections, arcs, and non-Cartesian gratings), all scaled to receptive field size. The responses of cells within each area were substantially modulated by each shape characteristic tested, with substantial overlap between areas by many response measures. Our analyses revealed many clear and reliable differences between areas in terms of the effectiveness of, and response modulation by, various shape characteristics. Grating stimuli were on average more effective than contour stimuli in V2 and V4, but the difference was more pronounced in V4. As a population, V4 showed greater response modulation by some shape characteristics (including simple shape characteristics) and V2 showed greater response modulation by many others (including complex shape characteristics). Recordings from area V1 demonstrated complex shape selectivity in some cells and relatively modest population differences in comparison with V2. Altogether, the representation of 2-dimensional shape characteristics revealed by this analysis varies substantially among the 3 areas. But surprisingly, the differences revealed by our analyses, individually or collectively, do not parallel the stepwise organization of the anatomical hierarchy. Commonalities of visual shape representation across hierarchical levels may reflect the replication of neural circuits used in generating complex shape representations at multiple spatial scales.     

Single cell integration of animate form, motion and location in the superior temporal cortex of the macaque monkey

This study investigated the cellular mechanisms in the anterior part of the superior temporal sulcus (STSa) that underlie the integration of different features of the same visually perceived animate object. Three visual features were systematically manipulated: form, motion and location. In 58% of a population of cells selectively responsive to the sight of a walking agent, the location of the agent significantly influenced the cell's response. The influence of position was often evident in intricate two- and three-way interactions with the factors form and/or motion. For only one of the 31 cells tested, the response could be explained by just a single factor. For all other cells at least two factors, and for half of the cells (52%) all three factors, played a significant role in controlling responses. Our findings support a reformulation of the Ungerleider and Mishkin model, which envisages a subdivision of the visual processing into a ventral 'what' and a dorsal 'where' stream. We demonstrated that at least part of the temporal cortex ('what' stream) makes ample use of visual spatial information. Our findings open up the prospect of a much more elaborate integration of visual properties of animate objects at the single cell level. Such integration may support the comprehension of animals and their actions.     

采用冷冻精子与新鲜精子进行卵胞浆内单精子注射的结果比较

目的　比较冷冻精子与新鲜精子进行卵胞浆内单精子注射 ( ICSI)助孕技术的治疗效果。　方法　对 1 6 1对不育夫妇进行 1 6 3个辅助生殖技术治疗周期 ,其中采用冷冻精子 47个周期 ,比较了冷冻精子组与新鲜精子组 1 1 6个周期的受精率、卵裂率、A级胚胎率与临床妊娠率。　结果　冷冻精子组 (组 I)的受精率为 77.6 %、卵裂率为 92 .9%、A级胚胎率为 6 5.4%、临床妊娠率为 45.5% ;新鲜精液严重异常组 (组 II)分别为 54 .4%、94.0 %、45.7%及 2 5.0 % ;新鲜精液轻、中度异常组 (组 III)分别为 73 .5%、92 .5%、46 .8%及 2 9.3 %。组 I的受精率、A级胚胎率和临床妊娠率明显高于组 II( P<0 .0 5) ;与组 III比较无显著性差异 ( P>0 .0 5)。　结论　患者本身的精子质量直接影响 ICSI的受精率 ,精子冷冻复苏处理不影响 ICSI的受精率、卵裂率和优质胚胎率     

A neural model of binocular integration and rivalry based on the coordination of action-potential timing in primary visual cortex

In normal vision, the inputs from the two eyes are integrated into a single percept. When dissimilar images are presented to the two eyes, however, they compete for perceptual dominance, so that one eye's view suppresses that of the other. Recent evidence suggests that this phenomenon, known as binocular rivalry, arises through competition between alternative stimulus interpretations in extrastriate cortex. Because eye-specific information appears to be lost at this stage, it remains unclear how the stimulus conditions that yield binocular rivalry are distinguished from those that produce stable single vision. Using a neural network that models the mammalian early visual system, I investigate here the hypothesis that congruent and conflicting stimuli are distinguished by their different effects on the relative timing of action potentials in primary visual cortex (V1), where monocular inputs are first combined. In the model, congruent stimulation of both eyes results in synchronization of discharges among binocular neurons in V1. By contrast, conflicting stimulation of the two eyes results in neuronal asynchrony in this area. This asynchrony then produces rivalrous response suppression at later stages in the visual pathway. Synchronization of firing in V1, however, prevents such competition, thereby ensuring non-rivalrous responses. These novel effects of spike timing on competition emerge naturally from the network dynamics. The results suggest that input-related differences in relative spike timing at an early stage of visual processing may play an important part in the phenomena both of binocular integration and rivalry; furthermore, they indicate that the temporal patterning of cortical activity may be a fundamental mechanism of selection among competing stimulus representations.      

A comparative study of the dimensional variability in different cell types of the human adrenal cortex in the newborn infant and the adult

The selection of the material for this study was governed by the idea that at the newborn like at the adult, the cortex of the adrenal gland is complete, including all the three zones, while medulla is not structured until 12-36 month; for this reason, we used only the cellular cortical elements. The quantitative method of evaluation of the cellular diameter, as well as the interpreting and correlation of the values with age, have confirmed that the dynamics of the cellular components of the adrenal gland depends on age, indicating significant differences. The cell diameter is usually bigger at the newborn compared with the adult (with zonal variations). The variability is relatively small which means that the individual values are placed in a limited field.     

Spectrotemporal analysis of evoked and induced electroencephalographic responses in primary auditory cortex (A1) of the awake monkey

Electroencephalography is increasingly being used to probe the functional organization of auditory cortex. Modulation of the electroencephalographic (EEG) signal by tones was examined in primary auditory cortex (A1) of awake monkeys. EEG data were measured at 4 laminar depths defined by current source density profiles evoked by best frequency (BF) tones. Midlaminar multiunit activity was used to define the tuning characteristics of A1 sites. Presentation of BF tones increased EEG power across the range of frequencies examined (4-290 Hz), with maximal effects evident within the first 100 ms after stimulus onset. The largest relative increases in EEG power generally occurred at very high gamma frequency bands (130-210 Hz). Increases in EEG power for frequencies less than 70 Hz primarily represented changes in phase-locked activity, whereas increases at higher frequencies primarily represented changes in non-phase-locked activity. Power increases in higher gamma bands were better correlated with the A1 tonotopic organization than power increases in lower frequency bands. Results were similar across the 4 laminar depths examined. These findings highlight the value of examining high-frequency EEG components in exploring the functional organization of auditory cortex and may enhance interpretation of related studies in humans.     

VIBE-Dixon序列骨髓脂肪定量与骨密度在女性骨质疏松症评价的研究

目的 探讨扫描层厚、翻转角对VIBE-Dixon序列测量腰椎骨髓脂肪分数的影响,探讨脂肪分数与骨密度(bone mineral density, BMD)的相关性,确定其与年龄、体质量指数（body mass index, BMI)、绝经、运动的关系。方法 选取116名符合纳入标准的志愿者,行腰椎MRI VIBE-Dixon扫描和DXA扫描。测量L1~4椎体骨髓的脂肪分数和骨密度。用组内相关性评估测量可重复性。采用Pearson线性相关分析评价2 mm与4 mm层厚的测量结果。采用Pearson线性相关分析评价5°、10°、15°翻转角得到的腰椎脂肪分数与骨密度的相关性。对年龄分组、BMI分组、运动情况分组均采用单因素方差分析,对绝经组与非绝经组采用t检验。结果 经两名技术专家测量的组内相关系数ICC=0.983。不同层厚结果之间存在明显相关性[r=0.981 (5°),0.969 (10°),0.972 (15°);P均﹤0.05]。不同翻转角、不同层厚结果与骨密度之间存在中度相关性[r=0.702 (2 mm-5°),0.732 (2 mm-10°),0.703(2 mm-15°),0.697(4 mm-5°),0.700(4 mm-10°), 0.714(4 mm-15°); P均﹤0.05]。腰椎椎体脂肪分数随年龄增加呈上升趋势,不同年龄组间差异有统计学差异[F=31.87(2 mm-5°), 28.41(2 mm-10°), 28.69 (2 mm-15°), 34.11(4 mm-5°), 34.05(4 mm-10°), 32.82(4 mm-15°); P﹤0.05]。腰椎椎体脂肪分数随BMI增加呈上升趋势;绝经女性FF值明显高于非绝经女性;运动强度对FF值没有影响。结论 VIBE-Dixon测量腰椎椎体脂肪分数具有可重复性;层厚和翻转角对评估影响较小;腰椎椎体脂肪分数能较好反映骨质量,并与腰椎骨密度呈负相关。     

不同容量复方倍他米松硬膜外注射治疗神经根型颈椎病的对照研究

【摘要】 目的 对比不同容量复方倍他米松硬膜外注射治疗神经根型颈椎病的疗效。方法 我科疼痛门诊自2012年1月~2012年12月共收治68例颈神经根型颈椎病患者,随机将患者分为两组,选取颈椎C6~7间隙作为穿刺点,按照硬膜外操作规程穿刺置管成功后,将得一支复方倍他米松注射液用生理盐水稀释,A组患者稀释至40 mL注射,B组稀释至20 mL注射,然后对照疗效。结果 本组第一疗程结果2周后,总有效率A组为97.1%(34/35),B组是84.8%(28/33)(P<0.05)。两组在穿刺过程及第一疗程结束后两周复诊未见头晕、恶心、神经损伤及硬膜外血肿等并发症。本组64例获随访,随访时间3个月~6个月,未完成随访的4例均为临床无效患者。结论 不同容量复方倍他米松硬膜外注射治疗神经根型颈椎病的疗效确切,但大容量组疗效优于小容量组。     

胸腰椎骨折脱位伴截瘫治疗回顾

作者对４３例胸腰椎骨折脱位伴截瘫进行了治疗回顾。其中全瘫１５例，不全瘫２８例。治疗总好转率，全瘫为２６．７％，不全瘫为７１．４％。并对脊柱节段与脊髓神经根的关系、脊髓损伤性质的判定、复位和内固定以及脊髓的减压途径等进行了讨论。     

A clinical comparative study on effects of intracavernous injection of sodium nitroprusside and papaverine／phentolamine in erectile dysfunction patients

Aim: To study the effect of intracavemous sodium nitropmsside (SNP), a nitric oxide (NO) donor, on penile erec-tion. Methods: Forty-two patients with erectile dysfunction (ED) were randomly assigned to receive SNP 300μgor the control drags (papaverine 30 mg phentolamine 1 mg) intracavemously crosswise one week apart. The penilelength, circumference and hardness after the administration of the experimental and control drags were assessed andcompared statistically. Results: (1) There was no significant difference between the changes in penile length andcircumference in the two occasions; (2) In 25 SNP and 28 control cases, the hardness of the penis was scored above100 as evaluated by the Vimg method (P > 0.05); (3) The duration of erection in the controls was longer than that inthe SNP, but there were three priapism in the controls and not a single one in the SNP; (4) there was no apparentchange in the heart rate and blood pressure in both occasions; other side effects were minimal except slight local     

经皮椎间孔脊柱内镜技术治疗高龄腰椎间盘突出症的疗效分析

目的:探讨经皮椎间孔脊柱内镜技术治疗高龄腰椎间盘突出患者的临床效果。方法:2016年3月～2019年3月我院收治的确诊为腰椎间盘突出症高龄患者130例,根据手术方式不同分为对照组和观察组,每组65例。对照组男37例,女28例,平均年龄66.4±5.3岁(61～75岁);给予椎板开窗髓核摘除术治疗;观察组男35例,女30例,平均年龄66.9±5.3岁(62～77岁),采用经皮椎间孔脊柱内镜技术治疗。术后收集两组数据,在不同角速度(60°/s和120°/s)下检测腰背肌生物力学性能,包括背部屈伸比(flexion extension ratio,F/E)、前降力矩(peak torque,PT)及平均功率(average power,AP);以投影栅轮廓法检测脊柱对称性,包括旋转角(RA)、侧弯角(M)及侧屈角比(LR);采用Oswestry功能障碍指数(Oswestry disability index,ODI)评分和MacNab标准评价术后患者治疗效果。结果:两组术前各指标比较无显著性差异(P0.05),观察组术后F/E[(72.16±20.17)%]、PT(86.54±15.39Nm)和AP (43.27±15.68W)较术前[(86.59±23.46)%、72.10±16.39Nm和28.41±16.34W]明显改善(P0.05),与对照组[(79.64±21.40)%、80.14±15.64Nm和37.69±14.38W)比较差异有显著性(P0.05);RA、M及LR观察组术后低于对照组(P0.05);对两组患者分别随访12个月,两组患者术后ODI值均降低,且术后观察组低于对照组(P0.05)。随访6个月及12个月时,对照组MacNab标准优良率分别为67.69%和72.31%,观察组分别为87.69%和93.85%,两组差异有统计学意义(P0.05)。结论:经皮椎间孔脊柱内镜技术对高龄腰椎间盘突出症患者的治疗,在腰背肌生物力学性能、脊柱对称性恢复方面有较高的应用价值,临床疗效优于椎板开窗髓核摘除术。     

A randomized comparative dose-ranging study of interferon-alpha and mitomycin-C as an internal control in primary or recurrent superficial transitional cell carcinoma of the bladder

OBJECTIVE: To compare, in a phase II study, the activity and toxicity of three dose levels of interferon-alpha, and of mitomycin-C given intravesically (as an internal control to validate the results), the primary objective being to investigate the percentage of complete responses (complete disappearance of a marker lesion) induced by the three interferon-alpha dose levels on a marker lesion; a secondary objective was to compare the interferon-alpha doses for toxicity. PATIENTS AND METHODS: In all, 115 patients were enrolled, with the inclusion criteria being multiple grade 1 or 2, stage Ta or T1, primary or recurrent transitional cell carcinoma of the bladder. Interferon-alpha (30, 50 and 80 MU) and mitomycin-C (40 mg) intravesical treatments were given as follows. Patients randomized to one of three interferon-alpha dose levels were treated weekly for 12 weeks. However, in week 9 (first cystoscopy after baseline) interferon-alpha treatment was stopped if there was a complete response or disease progression. Patients randomized to mitomycin-C were treated weekly for 8 weeks only and in week 9 underwent follow-up cystoscopy. RESULTS: Interferon-alpha at doses of 30, 50 and 80 MU gave response rates at 13 weeks of 19%, 33% and 41%, respectively. Although the response rates were higher for 50 and 80 MU than for 30 MU, the differences were not statistically significant. All three interferon-alpha groups had significantly lower response rates than the internal control, mitomycin-C (72%). The safety analysis showed that most of the adverse events were of mild to moderate severity. Adverse events were experienced by 37%, 37% and 48% of patients receiving 30, 50 and 80 MU interferon-alpha, respectively, and by 55% of patients receiving mitomycin-C. The corresponding rates for severe adverse events related to treatment were 9% for interferon-alpha and 10% for mitomycin-C. CONCLUSION: Ablative therapy with interferon-alpha was less effective than mitomycin-C in patients with superficial bladder cancer. Both drugs were well tolerated, although interferon-alpha appeared to have a slightly better overall safety profile.     

A quantitative study of the structure of trabecular bone in man,rhesus monkey,beagle and miniature pig

Summary This paper reports a quantitative comparison of trabecular bone structures in 4 mammalian species in terms of both measured path-length distributions across the trabeculae and marrow cavities as well as structural parameters derived from the pathlength data, that is, mean path lengths, percentage bone volume and the ratio of endosteal surface to bone volume. The path-length measurements have been made by scanning radiographs of thin sections of bone using an object-plane scanning microscope. Results are given for sets of up to 9 bones of a 9-year-old child, a 44-year-old man, a beagle, a rhesus monkey and a miniature pig. Mean cavity path lengths range typically from 1200 m in the adult man to 350 m in the miniature pig; mean trabecular path lengths range typically from 190 m in the child to 280 m in the miniature pig. Percentage bone volumes are lowest in adult man (16%) and highest in the miniature pig (45%) and the ratios for surface to volume show an opposite trend. Tentative estimates of skeletal values of surface-to-volume ratio are given, namely around 190 cm²/cm³ for all species studied except the miniature pig (130 cm²/cm³). Finally, an appendix illustrates the considerable effects of structural differences on radiation dosimetry.     

达芬奇机器人与胸腔镜肺段切除术治疗早期非小细胞肺癌的有效性对比

目的:对比研究达芬奇机器人与胸腔镜下肺段切除术患者的围手术期数据,评价机器人肺段切除术的临床价值.方法:回顾性分析2018年12月～2020年2月在郑州大学第一附属医院胸外科行机器人肺段切除术68例患者(机器人组)和胸腔镜下肺段切除术49例患者(胸腔镜组)的临床资料.比较两组患者肺段切除类型、术后疼痛评分、住院费用、手术时间、术中失血量、清扫淋巴结组数及个数、术后住院时间、胸腔引流管留置时间、引流总量以及术后并发症发生情况,从而明确两种手术方式的有效性差异.结果:机器人组比胸腔镜组术后疼痛评分更低[(1.94±0.64)分Vs(2.29±0.65)分,P<0.05];N1淋巴结清扫的组数[1(1～2)组Vs 2(1～3)组,P=0.002]和数量[2(1～3)枚Vs 3(1～4)枚,P=0.014]有差异,机器人组优于胸腔镜组;住院费用为80815.00(47914.79～113023.66)元和98213.41(65302.90～155561.88)元,机器人组高于胸腔镜组(P<0.05).结论:机器人和胸腔镜肺段切除术对非小细胞肺癌的早期治疗是安全可行的,而机器人肺段切除术可能有更好的N1淋巴结清扫效果.     

去甲泽拉木醛体外抑制Du-145细胞生长的初步研究

目的探讨去甲泽拉木醛对雄激素非依赖性前列腺癌细胞株Du-145的生长抑制作用及对其细胞周期改变的影响。方法分别用0、0.625、1.25、2.5、5、10、20、40μM浓度的去甲泽拉木醛作用于Du-145细胞0、24、48、72h后,以MTT法检测细胞生长活性;48h后于光镜高倍镜下观察不同浓度细胞形态学改变;24、48h后分别应用流式细胞仪检测0、1.25、10μM浓度去甲泽拉木醛作用后的细胞周期改变。结果去甲泽拉木醛对Du-145具有一定的生长抑制作用,并呈时间与浓度依赖性;细胞形态学观察发现,当药物作用48h后,随着药物作用浓度的增高,细胞逐渐呈现皱缩、变圆、脱落、碎裂、贴壁减少等现象;细胞周期分析发现,10μM作用48h后细胞中G0/G1期细胞增多,与对照组相比,差异具有统计学意义（P〈0.05）,但未出现明显凋亡峰。结论去甲泽拉木醛能显著抑制Du-145细胞的体外生长,其机制可能与将细胞阻滞在G0/G1期相关。     

A comparative clinical study on the effects of cardiopulmonary bypass with different flows and pressures on skeletal muscle cell metabolism in patients undergoing coronary bypass grafting

This study compares the effects of cardiopulmonary bypass with different flows and pressures on intracellular energy metabolism, acid-base equilibrium, and muscle water compartments in two groups of patients undergoing coronary artery bypass grafting. Eighteen patients (16 men and two women aged 54 +/- 7 years, New York Heart Association class I-II) undergoing low flow (flow rate 1.5 L/min/m2 at 26 degrees C), low pressure (mean arterial pressure 40 to 60 mm Hg) cardiopulmonary bypass, as well as 10 age-matched and sex-matched patients undergoing normal flow (flow rate 2.2 L/min/m2 at 26 degrees C), normal pressure (mean arterial pressure 60 to 80 mm Hg) bypass were studied. Intracellular acid-base equilibrium (intracellular pH and intracellular bicarbonate), cell energetics (adenosine triphosphate, diphosphate, and monophosphate, phosphocreatine, and lactate), and muscle water compartments were evaluated in specimens of the quadriceps femoris muscle obtained by needle biopsy before and at the end of cardiopulmonary bypass. In both the low flow-low pressure and normal flow-normal pressure groups, adenosine triphosphate levels were unchanged at the end of bypass, whereas phosphocreatine concentration was decreased; muscle total water and extracellular water increased without variations of intracellular water; muscle and plasma lactate increased as intracellular bicarbonate decreased; intracellular pH values remained unchanged. The present study suggests the following: (1) Cardiopulmonary bypass is associated with the overall preservation of intracellular compartment metabolism in skeletal muscle (about 40% of body cell mass) of patients undergoing coronary bypass grafting, even though low phosphocreatine values and increased plasma and muscle lactate values found at the end of bypass could be an expression of cell functional reserve exhaustion; (2) the effects of cardiopulmonary bypass on cell metabolism are comparable, regardless of the flows and pressures used.     

Surgery versus surgery and postoperative radiotherapy in squamous cell carcinoma of the buccal mucosa: A comparative study

Background: The efficacy of postoperative radiotherapy for squamous cell carcinoma of the buccal mucosa was evaluated. Methods: One hundred seventy-six patients treated between 1989 and 1993 were analyzed. One hundred fifteen patients were treated with surgery alone (Group 1), and 61 patients were treated with a combination of surgery and postoperative radiotherapy (Group 2). Results: Actuarial 3-year locoregional control in Groups 1 and 2 was 11% and 48% for patients with stage III + IV cancer (P=.001) and 71% and 75% for patients with stage I + II cancer (P=.74), respectively. On multivariate analysis for locoregional failure, surgical margin, bone invasion, high grade, and node involvement were significant factors in Group 1, whereas in Group 2 only tumor thickness was a significant factor. For local failure, margin, bone invasion, and stage in Group 1 and tumor thickness in Group 2 appeared as significant factors. For nodal failure, clinical nodal (cl N0 vs. N+) stage and grade in Group 1 and pathologic nodal stage (pN0 + 1 vs. pN2) in Group 2 were observed as significant factors. On subset analysis, postoperative radiotherapy was observed to have a significant advantage for surgical margins of 2 mm or less in both early pT (T1 + T2) (P=.019) and late pT (T3 + T4) (P=.016) stages. The local failure rate was higher if the time between surgery and radiotherapy was greater than 30 days. Conclusions: Postoperative radiotherapy was effective in decreasing locoregional failure in patients with close surgical margins, tumor thicker than 10 mm, high-grade tumors, positive node, and bone invasion. The effect of interval between surgery and postoperative radiotherapy on local failure was margin-dependent.