Pim-3对暴发性肝功能衰竭大鼠的肝组织修复效应及机制分析

目的 探讨Pim-3基因对暴发性肝功能衰竭(FHF)大鼠的肝组织修复效应.方法 将32只大鼠分为4组,健康对照组和3组处理组,每组8只.3组处理组分别以林格液、空载质粒(pEGFP-N2)和重组质粒(pEGFP-N2/Pim-3)溶液预处理大鼠,1 d后予脂多糖(LPS)/D-半乳糖胺(D-GalN)腹腔注射诱导FHF.8 h后或濒死期处死大鼠,采集血清和肝组织标本,检测血清转氨酶水平,RT-PCR和ELISA分别检测TNF-α和IL-1β基因表达及其血中浓度,原位末端凋亡(TUNEL)分析评估肝细胞凋亡水平,检测肝组织损伤程度.组间比较采用方差分析.结果 重组质粒注射能诱导目的 基因Pim-3和报告基因绿色荧光蛋白(GFP)在肝内高表达;与其他处理组相比,重组质粒组大鼠的生存率显著提高,血清转氨酶水平明显降低,且肝组织内出血坏死和炎性细胞浸润程度也明显减轻;重组质粒组肝凋亡指数为(10.2±6.9)%,显著低于林格液组的(83.1±12.6)%和空载质粒组的(79.9±13.4)%(P＜0.01);外源Pim-3基因的应用显著降低了肝组织内TNF-α和IL-1β mRNA的表达,以及血清TNF-α和IL-1β蛋白的分泌水平.结论 Pim-3基因有助于保护大鼠免于LPS/D-GalN诱导暴发性FHF的发生,其机制可能是抑制肝内炎性细胞因子TNF-α和IL-1β的表达和分泌.     

需肌醇酶1介导的内质网应激在暴发性肝功能衰竭肝细胞凋亡中的作用及其意义

目的 探讨需肌醇酶1(IRE1)介导的内质网应激肝细胞凋亡途径在暴发性肝功能衰竭中的作用及意义.方法 雄性Wistar大鼠共60只,暴发性肝功能衰竭模型组30只腹腔注射D-氨基半乳糖(D-GalN)+脂多糖(LPS),对照组30只腹腔注射0.9％氯化钠溶液,应用流式细胞技术观察两组大鼠肝细胞凋亡情况,分别采用免疫组织化学法及RT-PCR法动态观察肝组织中Caspase-12、IRE1蛋白及mRNA表达情况.多个独立样本采用Kruskal-Wallis H检验,同一时间点两两比较采用Mann-Whitney U检验,相关性分析采用秩相关.结果 模型组2、4、8和12h肝细胞凋亡率随着给药时间延长呈上升趋势(x2=25.475,P＜0.01),明显高于对照组(U=0,P＜0.01);模型组随着给药时间的延长肝细胞胞质Caspase-12、IRE1α蛋白表达增多,对照组无表达;模型组Caspase-12、IRE1α mRNA表达随着给药时间的延长而增加,8h达高峰,以后逐渐下降,各时间点的差异均有统计学意义(x2=23.983,x2=24.820;均P＜0.01),明显高于对照组(U =0,P＜0.01);IRE1与Caspase-12、细胞凋亡率均呈正相关(r=0.733,P＜0.01;r=0.715,P＜0.01),Caspase-12与肝细胞凋亡率呈正相关(r=0,586,P＜0.01).结论 IRE1介导的内质网应激肝细胞凋亡与暴发性肝功能衰竭的发生发展密切相关,早期干预内质网应激途径对防治肝功能衰竭可能具有保护作用.     

大鼠急性胰腺炎时胰腺腺泡细胞凋亡及Bax,Caspase-8的表达

目的:研究大鼠急性胰腺炎腺泡细胞凋亡情况,凋亡调控基因Bax与凋亡蛋白酶Caspase-8的表达及其同疾病严重程度的关系.方法:胆胰管逆行注入不同浓度去氧胆酸钠方法制备大鼠急性胰腺炎模型,设假手术(SO)组、急性水肿性胰腺炎(AEP)组和急性坏死性胰腺炎(ANP)组.采用TUNEL技术检测胰腺腺泡细胞的凋亡,RT-PCR与免疫组化方法分别分析胰腺组织Bax,Caspase-8 mRNA及蛋白的表达,对胰腺组织进行病理学评分并测定血清淀粉酶及IL-6,TNF-α含量.结果:与SO组比较,AEP与ANP组胰腺组织显示不同程度的病理损害,血清淀粉酶(63 413±6118,1 532 134±17 654 nkat/L vs 15 736±483 nkat/L,P＜0.01)及TNF-α(1.86±0.13,2.97±0.14μg/L vs 0.95±0.08 μg/L,P＜0.01),IL-6 (47.10±7.05,170.10±7.59 ng/L vs 29.20±4.47 ng/L,P＜0.01)浓度显著升高,且ANP组显著高于AEP组(P＜0.05);AEP与ANP组腺泡细胞凋亡指数显著升高(22.09±3.71,6.50±1.58 vs 0.13±0.05,P＜0.01),但ANP组显著低于AEP组(P＜0.05).同时发现,AEP与ANP组胰腺组织Bax (mRNA:1.530±0.501,1.046±0.337;蛋白:453.7±30.5,339.4±26.7)和Caspase-8(mRNA:0.595±0.17,0.505±0.173;蛋白:3606±337,3134±231) mRNA及蛋白表达水平均显著高于SO组(Bax mRNA:0.613±0.244,Bax蛋白:245.2±30.0;Caspase-8mRNA:0.357±0.130,Caspase-8蛋白:2396±266)(P＜0.01),ANP组Bax mRNA及蛋白表达水平显著低于AEP组(1.046±0.337,339.4±26.7 vs 1.530±0.501,453.7±30.5,P＜0.05),ANP组Caspase-8 mRNA及蛋白表达水平低于AEP组,但差异不具有显著性意义.结论:急性胰腺炎时胰腺腺泡细胞发生凋亡伴随凋亡调控基因Bax与凋亡蛋白酶Caspase-8表达增加,并同病情严重程度呈负相关关系.     

通里攻下法对急性肝衰竭大鼠肝细胞凋亡的影响(摘要)

目的:探讨通里攻下法对内毒素脂多糖(LPS)致急性肝衰竭大鼠肝细胞凋亡的影响。方法:以LPS D-GalN联合制备大鼠急性肝衰竭模型,观察大鼠肝组织病理学变化;以免疫组化法(SP法)检测Fas、FasL蛋白在大鼠肝组织中的表达情况,并观察通里攻下中药对肝细胞凋亡的作用。结果:LPS D-GalN可引起严重的急性肝坏死并有广泛的肝细胞凋亡,伴Fas、FasL蛋白在肝细胞中表达增强;肝细胞Fas/FasL阳性     

Fas/FasL、Bcl-2/Bax、Caspase-8在大鼠非酒精性脂肪性肝病中的作用机制

目的:探讨肝细胞凋亡及其相关因素Fas/FasL、Bcl-2/Bax蛋白及Caspase-8 mRNA的表达在大鼠非酒精性脂肪性肝病(non-alcoholic fatty liver disease,NAFLD)中的作用.方法:采用改良高脂饮食建立大鼠NAFLD模型,以正常饮食设立对照组.HE染色观察肝脏脂肪变、炎症活动和纤维化程度,采用流式细胞仪法测肝细胞凋亡百分数;免疫组织化学法检测Fas、FasL、Bcl-2及Bax在肝组织中表达情况;实时荧光定量PCR法检测肝脏Caspase-8 mRNA的表达.结果:NAFLD模型组脂肪变性明显,纤维化和炎症活动度记分均显著高于正常对照组.流式细胞仪检测显示,与对照组比较,实验组大鼠肝细胞凋亡百分数增加,随造模时间延长凋亡率增加更明显(均P<0.01);免疫组织化学染色显示随着肝脏脂肪变加重,Fas、FasL蛋白染色加深,阳性细胞数增加;Bcl-2、Bax在对照组的表达均为散在弱阳性,实验组4、8、12wk阳性细胞数渐增加,并在脂肪变明显的部位着色深且随着脂肪肝的进展,Bcl-2/Bax比率进行性下降.实时荧光定量PCR法显示Caspase-8 mRNA表达量在高脂组中显著高于对照组(均P<0.01),且随肝脏脂肪变及炎症加重呈进行性上升.结论:在NAFLD发生过程中,肝细胞凋亡促进NAFLD大鼠病情进展;Fas、FasL、Caspase-8 mRNA相关调控蛋白的活化是引起NAFLD脂肪变性、炎症及纤维化的重要因素.细胞凋亡调节蛋白Bax、Bcl-2表达上调,二者表达的相对比例发生异常,这可能是NAFLD中肝细胞发生凋亡的重要原因之一.     

肾气丸对非酒精性脂肪性肝炎大鼠Bcl-2/Bax、Fas/FasL信号通路的影响

目的:观察Bcl-2/Bax、Fas/Fas L介导的信号转导通路在高脂饮食诱导的非酒精性脂肪性肝炎大鼠的作用及肾气丸对其的影响。方法:采用高脂饲料连续喂养12周建立大鼠非酒精性脂肪性肝炎模型,同时以肾气丸进行干预12周。HE染色观察大鼠肝组织病理组织学变化,免疫组织化学检测肝组织中Fas、Fas L、Bcl-2、Bax、Caspase-8蛋白的表达;Realtime-PCR法检测肝组织Caspase-8 mRNA表达。结果:模型组大鼠肝组织Bcl-2、Bax、Fas、Fas L蛋白以及Caspase-8 mRNA和蛋白表达均较正常组显著增加(P<0.01),Bcl-2/Bax比值较正常组明显的降低(P<0.05);大鼠肝组织Caspase-8蛋白表达与Fas、Fas L蛋白表达均呈明显正相关(r分别为0.907、0.804,P均<0.01);予以肾气丸干预后,Bax、Fas、Fas L蛋白的表达以及Caspase-8 mRNA和蛋白的表达均较模型组明显的降低(P<0.05),Bcl-2/Bax比值较模型组明显的增加(P<0.05),Bcl-2蛋白的表达与模型组比较差异无显著性意义(P>0.05)。结论:肾气丸可能通过影响Bcl-2/Bax、Fas/Fas L信号转导通路,下调Bax、Fas、Fas L、Caspase-8表达,减少肝细胞的脂性凋亡,从而防治大鼠非酒精性脂肪性肝炎的发生发展。     

急性肝衰竭TNF-α、Caspase-3及TGF-β1 mRNA的表达及罗格列酮的干预

目的: 观察D-氨基半乳糖(D-Ga lN)联合脂多糖(LPS)诱导的小鼠急性肝衰竭TNF-α、Caspase-3、TGF-β1 mRNA的表达,并探讨罗格列酮的干预作用.方法: ♂昆明小鼠随机分为3组: 正常组、对照组、干预组.对照组和干预组以D-Ga lN/LPS腹腔注射构建小鼠急性肝衰竭模型,正常组则相应予以生理盐水腹腔注射;干预组于造模前2 h予以罗格列酮灌胃,正常组和对照组则相应予以生理盐水灌胃.比较各组小鼠血清丙氨酸氨基转移酶(ALT)和天门冬氨酸氨基转移酶(AST)水平,肝组织病变程度及肝组织TNF-α、Caspase-3,TGF-β1 mRNA的表达水平.结果: D-GalN联合LPS腹腔注射成功构建了小鼠急性肝衰竭模型,对照组肝组织中TNF-α、Caspase-3、TGF-β1 mRNA的表达较正常组明显增高( P＜0.001);干预组小鼠血清ALT,AST水平明显低于对照组(403.6±76.1 U/L vs 3664.8±646.1 U/L,464.6±63.0 U/L vs 3514.0±468.9 U/L,均P＜0.001),肝组织中TNF-α、Caspase-3、TGF-β1 mRNA表达水平明显低于对照组(0.270±0.042 vs 0.459±0.072,0.388±0.033 vs 0.553±0.033,0.261±0.031 vs 0.403±0.042,均P＜0.001);与对照组比较,干预组肝组织炎性细胞浸润明显减少,肝细胞以变性为主,未见明显坏死.结论: 罗格列酮可能通过下调T N F - α、Caspase-3、TGF-β1的表达对D-GalN/LPS小鼠急性肝衰竭起保护作用.     

五田保肝液对酒精性肝病大鼠肝细胞凋亡的影响机制

目的 探讨五田保肝液对酒精性肝病大鼠肝细胞凋亡和肝组织肿瘤坏死因子(TNF)-α、Caspase-3 mRNA表达的影响.方法 将100只Wistar大鼠随机分成6组:对照组10只、模型组、五田保肝液低、中、高剂量组、易善复组各18只,采用白酒辅以吡唑、玉米油的混合食料灌胃的方法建立大鼠酒精性肝病模型,12 w末处死大鼠,TUNEL法检测肝细胞凋亡情况,实时定量RT-PCR法检测TNF-α、Caspase-3 mRNA的表达.结果 五田保肝液可降低酒精性肝病大鼠肝细胞的凋亡指数(AI)和肝组织TNF-α、Caspase-3 mRNA的表达,且以中、高剂量效果更加显著;TNF-α、Caspase-3 mRNA的表达与AI呈正相关(r=0.803,r=0.795,P＜0.01).结论 五田保肝液尤其是中、高剂量对大鼠酒精性肝病肝细胞凋亡具有抑制作用,其机制可能与降低TNF-α、Caspase-3 mRNA的表达有关.     

甜菜碱对酒精性肝损伤大鼠凋亡基因caspase-12表达的影响

目的:研究甜菜碱对凋亡基因caspase-12表达的影响,探讨其抗酒精性肝损伤(ALD)大鼠肝细胞凋亡的机制.方法:采用酒精加鱼油灌胃配合高脂饮食建立酒精性肝损伤模型,应用半定量逆转录聚合酶链反应(RT-PCR)法和免疫组化法检测大鼠肝组织凋亡基因caspase-12mRNA和蛋白水平.结果:与正常组比较,模型组大鼠肝组织caspase-12表达明显增强(mRNA:1.00vs0.18,P<0.01;蛋白:0.2969±0.0451vs0.0526±0.0234,P<0.01),但高、低剂量甜菜碱能抑制其表达(mRNA:0.10,0.12vs1.00,P<0.01;蛋白:0.1215±0.0130,0.1850±0.0085vs0.2969±0.0451,P<0.01).甜菜碱高、低剂量组之间有显著差异(mRNA:0.10vs0.12,P<0.05;蛋白:0.1215±0.0130vs0.1850±0.0085,P<0.05).结论:甜菜碱能抑制凋亡基因caspase-12mRNA和蛋白的表达,可能是其减少凋亡的机制之一.     

Caspase-12在D-氨基半乳糖联合脂多糖诱导小鼠急性肝功能衰竭中的表达及作用

目的探讨Caspase-12在D-氨基半乳糖(D-Gal)/脂多糖(LPS)诱导小鼠急性肝功能衰竭发生发展过程中表达水平的变化及Caspase-12介导的内质网应激肝细胞凋亡途径在急性肝功能衰竭中的作用。方法以D-Gal/LPS联合腹腔注射诱导小鼠急性肝功能衰竭建立实验模型,在不同时间点动态检测血清氨基转移酶水平和观察肝组织病理变化,评估肝细胞凋亡和肝坏死演变过程;应用琼脂糖凝胶电泳检测肝细胞DNA凋亡条带;用半定量逆转录聚合酶链反应检测肝组织中Caspase-12 mRNA表达水平;west- ern blot检测Caspase-12、Bip/GRP78蛋白表达。结果药物诱导5h时肝组织中典型凋亡细胞增多,血清丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)开始升高,Caspase-12 mRNA表达明显增加, Caspase-12蛋白量表达反而减少;7h镜下出现大量肝细胞凋亡和坏死,ALT、AST水平达高峰,分别为(2564±1384)U/L和(1198±497)U/L,正常对照组为(59±17)U/L和(135±12)U/L,Caspase- 12 mRNA表达仍增加,Caspase-12蛋白表达量继续降低;9h 肝细胞坏死明显,伴散在凋亡细胞,ALT、AST水平明显下降,Caspase-12 mRNA表达较7 h下降。Bip/GRP78蛋自表达从5 h开始,至7 h逐渐增加。结论D-Gal/LPS诱导小鼠急性肝功能衰竭早期Caspase-12 mRNA表达水平逐渐升高,后期(7-9 h)降低,与肝细胞凋亡发生的时相一致;Caspase-12蛋白酶因内质网应激而被大量活化,提示Caspase-12介导的内质网应激肝细胞凋亡参与炎症性急性肝功能衰竭的发生发展,是急性肝功能衰竭中肝细胞损伤的重要机制之一,提示早期干预Caspase-12表达及活化对急性肝功能衰竭可能具有保护作用。     

The immunoneuroendocrine role of melatonin

Abstract: A tight, physiological link between the pineal gland and the immune system is emerging from a series of experimental studies. This link might reflect the evolutionary connection between self-recognition and reproduction. Pinealectomy or other experimental methods which inhibit melatonin synthesis and secretion induce a state of immunodepression which is counteracted by melatonin. In general, melatonin seems to have an immunoenhancing effect that is particularly apparent in immunodepressive states. The negative effect of acute stress or immunosuppressive pharmacological treatments on various immune parameters are counteracted by melatonin. It seems important to note that one of the main targets of melatonin is the thymus, i.e., the central organ of the immune system. The clinical use of melatonin as an immunotherapeutic agent seems promising in primary and secondary immunodeficiencies as well as in cancer immunotherapy. The immunoenhancing action of melatonin seems to be mediated by T-helper cell-derived opioid peptides as well as by lymphokines and, perhaps, by pituitary hormones. Melatonin-induced-immuno-opioids (MHO) and lymphokines imply the presence of specific binding sites or melatonin receptors on cells of the immune system. On the other hand, lymphokines such as -γ-interferon and interleukin-2 as well as thymic hormones can modulate the synthesis of melatonin in the pineal gland. The pineal gland might thus be viewed as the crux of a sophisticated immunoneuroendocrine network which functions as an unconscious, diffuse sensory organ.     

Response of rat pineal melatonin to calcium, magnesium, and lithium is circadian stage dependent

Abstract: Herein we documented the response of pineal melatonin production to electrolytes known to be effective on pineal function in view of a possible circadian stage dependence. We studied the release of melatonin by perifused rat pineal glands at 2 different circadian stages corresponding to the middle of the light and dark periods, i.e., respectively, 7 and 19 HALO (Hours After Light Onset, L:D = 12:12). The initial efflux rates were, as expected, much higher in the perifusates of glands removed from rats sacrificed during the dark phase than of those removed during the light phase. After 3 hr of perifusion, melatonin release reached similar levels which were found constant up to the 8th hr of perifusion, whatever the circadian stage. Perifusion of the glands with physiological concentrations for the rat of calcium (5.2 mmol/1) and magnesium (1.34 mmol/1) resulted in a stimulatory effect on the pineal glands removed from rats sacrificed in the middle of the dark period (19 HALO), whereas no effects were observed on the pineal glands removed from rats sacrificed during the light (7 HALO). Lithium (0.28 and 0.55 mmol/1) was ineffective on melatonin release in pineal glands removed 7 and 19 HALO. Our results show differences in the initial efflux rates of melatonin and in the response of perifused pineal glands to calcium and magnesium according to the circadian stage.     

Changes in connexin43, the gap junction protein of astrocytes, during development of the rat pineal gland

Abstract: The abundance of gap junctions between rat pineal astrocytes formed by connexin43 (Cx43) was studied during development. Levels and distribution of Cx43 were measured by immunoblotting and indirect immunofluorescence, respectively. The amount of Cx43 in cells located within the gland was low until about the 7th postnatal day and increased to adult values between the 14th and 21st days postpartum. Although astrocytes, recognized by their vimentin immunoreactivity, were scarce before birth, they were abundant by the 7th postnatal day suggesting that the low levels of Cx43 found at this age corresponded to a low expression of this protein. Localization of the immunoreactivity to Cx43 and vimentin showed a close correlation, indicating that mature or immature pineal astrocytes form gap junctions made of Cx43. Since Cx43 levels attained their adult values at about the time the innervation and the functional state of the gland reached maturity (2–3 weeks after birth), it is proposed that astrocyte gap junctions are involved in the function of the adult rat pineal gland.     

Conservative management of perforated duodenal diverticulum： A case report and review of the literature

Duodenal diverticula are a relatively common condition. They are asymptomatic, unless they become complicated, with perforation being the rarest but most severe complication. Surgical treatment is the most frequently performed approach. We report the case of a patient with a perforated duodenal diverticulum, which was diagnosed early and treated conservatively with antibiotics and percutaneous drainage of secondary retroperitoneal abscesses. We suggest this method could be an acceptable option for the management of similar cases, provided that the patient is in good general condition and without septic signs.     

Presence of immunoreactive growth hormone and prolactin in the ovine pineal gland

Abstract: The use of antisera raised against bovine growth hormone (GH) and ovine prolactin (PRL) enabled the detection of related immunoreactive (ir) sequences of proteins in ovine pineal tissue. The isolation of PRL-like ir-material was accomplished using a 0.25 M ammonium sulphate (pH 5.5) extraction followed by ethanol precipitation, whereas the resulting 2.0 M ammonium sulphate (pH 7.0) precipitate contained a GH-like immunoreactivity. Gel chromatography of the GH-like immunoreactivity (Sephadex G-100) indicated the presence of several GH-like fragments ranging in the M_r range of 7,000 to 55,000. Analyses of the PRL-like ir-material found in pineal tissue on HPLC using a TSK 545-DEAE column led to the resolution into a single peak of immunoreactivity. A single peak of activity was also observed following chromatofocusing and hydrophobic interaction chromatography of the ir-peak from the TSK 545-DEAE column. The PRL-like ir-material inhibited the binding of [¹²⁵I]ovine PRL-S14 to anti-ovine PRL antibodies without showing an affinity for binding to anti-rat PRL or anti-bovine GH antibodies. Scatchard analysis of the binding of pineal PRL-like ir-material and pituitary ovine PRL-S14 to liver membranes from day-20 pregnant rats revealed similar affinity constants (K_a of 4.7 ± 0.2 × 10⁹ M^-1). In addition, the replication of Nb 2 Node rat lymphoma cells was stimulated by pineal PRL-like ir-material, an effect known to be specific for lactogenic hormones. The pineal PRL-like immunoreactivity appeared on sodium dodecyl sulfate polyacrylamide gels as a single major band of M_r 24,000. The functional status of PRL-and GH-like ir-material in the ovine pineal remains to be determined, but evidence is presented that the overall protein synthesis rate of the rat pineal responded to circulating concentrations of PRL.     

Microbiology of human immunodeficiency virus anorectal disease

PURPOSE: Individuals who are seropositive for the human immunodeficiency virus are at high risk for opportunistic infection and anorectal disorders. Little prospective information is available regarding anorectal pathogens in these patients. METHODS: One hundred sixty-three HIV-seropositive patients presented to the colorectal clinic between 1989 and 1992. Forty-seven (29 percent) patients were thought to have an infectious process and were prospectively studied using a standardized multiculture protocol. RESULTS: Mean age was 33 (range, 19–59) years. All were male; high-risk behavior accounted for 87 percent of HIV transmissions. Presenting complaints included anorectal pain (79 percent), pus per anum (28 percent), and blood per anum (26 percent). Examination revealed perianal tenderness (60 percent), condyloma (38 percent), perianal ulcers (38 percent), and anal fissures (34 percent). Sixty-six sets of cultures were performed; 28 patients had one set, 15 had two sets, and 4 had three sets. Thirty-two of these 47 patients (68 percent) had positive cultures including herpes (50 percent), cytomegalovirus (25 percent),Neisseria gonorrhoeae (16 percent), chlamydia (16 percent), acidfast bacilli (2 percent), and others (9 percent). Six of 32 patients with positive cultures had more than one organism cultured. Sixteen (50 percent) patients with positive cultures were treated medically, 8 (25 percent) were treated surgically and 8 (25 percent) were treated with both modalities. Sixty-one procedures were performed on 17 patients for condylomata. Eighteen patients had 20 procedures for abscesses, 50 percent of whom had positive cultures for other than common bowel flora; all improved. Fourteen patients underwent 33 procedures for perianal fistulas.Mycobacterium fortuitum was cultured from one patient who required 13 procedures for abscesses and fistulas. Forty-five (96 percent) patients were followed for an average of 12.5 months ±2.9 SEM (range, 1–94 months). Symptoms were improved or resolved in 22 of 32 (69 percent) patients with positive cultures and in 11 of 13 (84 percent) with negative cultures. CONCLUSIONS: Specific pathogens may often be identified in human immunodeficiency virus-seropositive patients with anorectal disorders if aggressively sought. Although patients without specific pathogens identified may be expected to improve with planned empiric treatment, positive identification allows more directed therapy.