记忆力缺损老年人向痴呆移行过程中的关联性负变化

目的　探讨记忆力缺损老年人 (AMI)在向痴呆移行过程中关联性负变化 (CNV)的特征与趋势。　方法　将研究组和对照组行CNV和长谷川痴呆量表 (HDS)检查。 2～ 3年后对研究组中的 2 2例进行CNV和HDS复测。　结果　研究组命令信号 (S2 )开始至按键间的时间 (RT)和S2 后负变化 (PINV)的时程分别为 (2 84 3± 170 6 )ms和 (35 7 6± 2 0 4 7)ms,较对照组〔(149 8± 10 1 7)ms和(2 19 7± 135 5 )ms〕延长 (P <0 0 5或 0 0 1) ;期待波 (EW)波幅及其面积分别为 (15 3± 1 0 ) μV和 (74 6± 5 3 6 ) μV2 ,较对照组〔(2 1 1± 7 3) μV和 (112 0± 5 4 1) μV2 )〕缩小 (P <0 0 1) ;EW波形不规则、不稳定。 2～ 3年后复测 2 2例 ,HDS评分为 (19 6± 3 2 )分 ,较其第 1次〔(2 6 0± 3 8)分〕减低 (P <0 0 1)。CNV指标中RT为 (2 6 2 6± 71 6 )ms,较第 1次〔(2 10 1± 91 6 )ms〕延长 (P <0 0 5 ) ;PINV时程为 (175 3± 2 9 8)ms,较第 1次〔(32 1 5± 2 2 2 4)ms〕缩短 (P <0 0 1) ;EW的波幅和面积分别为 (14 3± 5 2 ) μV和(6 5 2± 40 0 ) μV2 ,PINV的波幅和面积分别为 (7 0± 4 0 ) μV和 (2 9 4± 46 3) μV2 ,均较第 1次缩小 (P<0 0 5或 0 0 1) ;EW波形不稳定与减低。　结论　CNV波幅     

2型糖尿病肾病患者血清细胞粘附分子变化与氧化应激的关系

目的　探讨 2型糖尿病肾病患者 (DN)血清细胞粘附分子变化及其与氧化应激的关系。　方法　检测DN患者血清可溶性细胞间粘附分子 1(sICAM 1)、可溶性血管细胞粘附分子 1(sVCAM 1)、血清丙二醛 (MDA)含量和超氧化物歧化酶 (SOD)活性。　结果　早期DN及DN患者血清sVCAM 1水平〔分别为 (1 75± 0 48)、(1 91± 0 2 7)mg/L〕明显高于对照组〔(1 6 7± 0 72 )mg/L ,P <0 0 5和0 0 1〕 ,DN组明显高于单纯糖尿病 (DM)组〔(1 5 8± 0 39)mg/L ,P <0 0 5〕 ;DM组、早期DN组和DN组患者血清sICAM 1〔分别为 (75 6 0 0± 12 5 47)、(80 2 2 1± 12 4 81)、(897 6 0± 10 5 80 ) μg/L〕明显高于对照组〔(5 82 6 4± 10 2 73) μg/L ,P <0 0 0 1〕 ,其中DN组明显高于单纯DM组和早期DN组 (分别P <0 0 1和<0 0 5 ) ;单纯DM组、早期DN组和DN组患者血清SOD活性〔分别为 (86 5 9± 13 85 )、(85 6 9±11 32 )、(71 73± 16 35 )NU/L〕显著性低于对照组〔(92 73± 11 2 5 )NU/ml,P <0 0 1〕 ,MDA含量〔分别为(3 99± 1 36 )、(4 2 6± 1 95 )、(6 5 0± 2 98)nmol/ml〕显著性高于对照组〔(3 72± 0 5 7)nmol/ml,P <0 0 1〕。DM患者血清sVCAM 1与sICAM 1、收缩压、尿素氮 (BUN)和肌酐 (Cr)呈正相     

糖尿病大鼠一氧化氮与骨代谢变化的研究

目的　研究糖尿病 (DM )大鼠血清一氧化氮 (NO)与早期骨代谢改变的关系。方法2 0只SD大鼠分为 2组 ,一组以链脲佐菌素诱导建立糖尿病 (STZ DM )大鼠模型 ,另一为正常对照组 ,测定 2组大鼠的空腹血糖 (FBG)、HbA1c、血清胰岛素、全身、股骨和腰椎骨密度 (BMD)、骨代谢相关指标〔血清钙、骨钙素、降钙素、甲状旁腺素 (PTH)、维生素D3 及尿吡啶酚 /肌酐比〕和血清NO水平。结果　STZ DM大鼠与正常对照组相比 ,血清NO水平显著升高〔(5 1.3± 11.9vs 38.1± 12 .0 )μmol/L ,P <0 .0 1〕 ;全身、股骨和腰椎的BMD显著降低〔(0 .15± 0 .0 7vs 0 .2 1± 0 .0 2 ) g/cm2 ,P<0 .0 1;(0 .16± 0 .0 2vs 0 .19± 0 .0 3) g/cm2 ,P <0 .0 5 ;(0 .12± 0 .0 4vs 0 .18± 0 .0 6 ) g/cm2 ,P <0 .0 5〕 ;血清钙浓度显著升高〔(135 .9± 11.3vs 117.2± 6 .5 )mg/L ,P <0 .0 0 1〕 ,骨钙素水平显著升高〔(0 .0 7± 0 .0 4vs 0 .0 5± 0 .0 1) μg/L ,P <0 .0 5〕 ,维生素D3 水平显著降低〔(7.6± 1.9vs 11.6± 4 .1)μg/L ,P <0 .0 5〕 ,尿吡啶酚 /肌酐显著降低〔(4.8± 0 .8vs 75 .8± 6 0 .7)nmol/mmolCr,P <0 .0 1〕 ;而降钙素和PTH水平改变无统计学意义。相关性分析显示 ,血清NO与尿吡啶酚排泄呈负相关 (r= - 0 .74 ,     

原发性高血压患者与正常人心率变异性的比较

目的　研究原发性高血压 (EH)患者与正常人心率变异性 (HRV)的比较。方法　 5 0例EH患者和 5 0例健康成人 (对照组 )行 2 4h动态心电图检查各 1次 ,分析心率时域和频域指标。结果　EH患者与对照组比较 ,代表心率总变异程度的SDNN〔(10 8 4± 33 2 )msvs (130 6± 35 6 )ms,P <0 0 1)〕、SDANN〔(96 2± 2 5 5 )msvs (118 3± 2 4 7)ms,P <0 0 1)〕和SDNNI〔(41 2± 16 3)msvs (5 4 1± 17 6 )ms,P <0 0 1)〕明显下降 ;代表迷走神经功能的RMSSD〔(2 8 4±10 3)msvs (32 8± 11 2 )ms,P <0 0 5 )〕和PNN5 0〔(6 1±1 5 )msvs (7 2± 1 8)ms ,P <0 0 5 )〕也有下降 ;频域指标VLF〔(186 2 7± 82 1 6 )Hzvs (15 34 8± 738 5 )Hz,P <0 0 5 )〕和LF〔(472 3± 2 6 5 8)Hzvs (396 2± 113 6 )Hz ,P <0 0 5 )〕升高 ,HF〔(112 5± 86 4 )Hzvs (2 0 3 6± 94 7)Hz,P <0 0 1)〕明显下降。结论　分析EH患者HRV有助于预测心脏功能受损的程度和预后     

高浓度葡萄糖对人胰岛β细胞凋亡影响的分子机制

目的　初步探讨高浓度葡萄糖对人胰岛 β细胞凋亡的影响及其分子机制。　 方法　分离培养人胰岛细胞 ,并分为对照组、高糖组和高糖 氨基胍组 ,3 7℃ ,5 %CO2 培养 72h ,测定培养液上清液中胰岛素、一氧化氮 (NO)、还原性谷胱甘肽 (GSH)水平。原位末端核苷酸标记法 (TUNEL)和胰岛素免疫组化双染色法及ELISA法检测胰岛 β细胞凋亡 ,RT PCR检测胰岛细胞p5 3、Bcl 2和胰岛素基因启动转录因子 1 (PDX 1 )mRNA表达水平。　结果　高糖组胰岛 β细胞凋亡小体富计因子(1 91± 0 6 9)、β细胞凋亡率 (1 4 8% )、NO〔(1 82 3± 1 5 5 ) μmol/L〕和 p5 3mRNA(0 3 0 6± 0 0 3 9)表达水平均显著高于高糖 氨基胍组〔分别为 1 1 9± 0 3 3、6 8%、(1 5 4 2± 1 9 7) μmol/L、0 1 3 9±0 0 6 9,P <0 0 1〕和对照组〔分别为 1 0 6± 0 2 6、4 2 %、(1 1 7 3± 2 1 7) μmol/L、0 1 2 5± 0 0 1 5 ,P <0 0 5〕 ,而胰岛素释放量、GSH、bcl 2mRNA和PDX 1mRNA表达水平则显著低于高糖 氨基胍组(P <0 0 5 )和对照组 (P <0 0 5 )。　结论　高浓度葡萄糖可通过诱导人胰岛 β细胞凋亡及PDX 1表达降低使胰岛素分泌减少 ,其机制与高糖状态下胰岛 β细胞抗氧化能力降低引起NO介导的p5 3高表达和PDX 1低表     

气道内支架置入术治疗老年人癌性气道狭窄

一、对象和方法　　 1.对象 :选自我院 1997年 1月至 1998年 12月住院的晚期肺癌患者 2 2例 ,男 15例 ,女 7例 ,年龄 6 0～ 70岁 ,平均(6 6 0± 3 7)岁。鳞癌 16例 ,腺癌 6例。经影像学和气管镜确定狭窄部位 ,其中主气管 9例 ,左总支气管 7例 ,右总支气管 5例 ;狭窄口直径分别为 5 0～ 10 0ｍｍ〔(6 8± 3 0 )ｍｍ〕、4 0～ 6 0ｍｍ〔(4 8± 1 4)ｍｍ〕、3 0～ 6 0ｍｍ〔(4 5±1 4)ｍｍ〕 ,狭窄长度分别为 15 0～ 35 0ｍｍ〔(2 1 1± 8 2 )ｍｍ〕、11 0～ 32 0ｍｍ〔(2 5 0± 8 0 )ｍｍ〕、11 0～ 2 2 0ｍｍ〔(16 0± 5 5 )ｍ…     

B超检测老年冠心病患者颈动脉内-中膜厚度和肱动脉舒张功能的变化

目的　观察老年冠心病患者的颈动脉内 中膜厚度 (IMTc)及高脂餐后肱动脉舒张功能的变化。　方法　采用高分辨超声检测技术观察老年冠心病患者 (30例 )、老年健康人 (2 2例 )及非老年健康人 (11例 )的IMTc及高脂餐前后肱动脉血流介导的血管舒张功能 (FMD)的变化。　结果　老年冠心病组的IMTc〔(1 13± 0 2 3)cm〕显著高于老年健康组〔(0 94± 0 2 0 )cm〕及非老年健康组〔(0 78± 0 14)cm〕 ,差异均有非常显著性 (均为P <0 0 1)。老年冠心病组的空腹FMD〔(3 4± 1 7) %〕显著低于老年健康组〔(5 3± 3 3) % ,P <0 0 5〕及非老年健康组〔(8 1± 3 9) % ,P <0 0 1〕。年龄与IMTc呈正相关 (r=0 44 4,P <0 0 5 ) ,与空腹FMD呈负相关 (r =- 0 6 5 0 ,P <0 0 0 1) ;高脂餐后 3组受试者的FMD显著减弱〔分别为 (0 6± 0 7) %、(2 6± 2 0 ) %及 (4 2± 2 8) % ;均为P <0 0 0 1〕 ,其中老年冠心病组的FMD下降程度〔ΔFMD % ,(76 7± 10 4) %〕显著高于老年健康组〔(5 4 1± 3 7) %〕及非老年健康组〔(5 0 8± 3 3) %〕 ,差异有显著性 (均为P <0 0 5 )。　结论　老年冠心病患者存在严重的颈动脉粥样硬化与血管舒张功能失调 ,高脂餐后血管舒张功能的进一步减弱 ,可能是诱发急性冠状动脉事     

前列腺素E2促进老年大鼠成骨细胞骨形成及其机制研究

目的　探讨前列腺素E2 (PGE2 )对老年雄性大鼠胫骨上段松质骨的作用。　方法　取2 0月龄Wistar雄性大鼠 ,分别皮下注射PGE2 (3mg·kg 1·d 1) 10d和 30d。用体内双荧光标记法、不脱钙组织切片 ,以骨组织形态计量学方法观察胫骨上段松质骨骨小梁和骨髓腔的动态和静态参数变化。　结果　PGE2 作用 10d骨小梁表面成骨细胞周长OB/BS〔(12 3± 7 6 ) %〕和类骨质周长OS/BS〔(2 0 4± 7 2 ) %〕明显高于对照组〔(1 6± 0 7) %和 (4 3± 1 7) % ,P <0 0 1〕 ,骨小梁表面和髓腔出现多层排列的前成骨细胞OPC ,形成多细胞成分而钙化不全的新生骨小梁WB ;PGE2 作用 30d矿化骨形成率BFR/BV〔(815 4± 137 9) %·年 1〕和骨量BV/TV〔(4 2 1± 12 6 ) %〕明显高于对照组〔(15 4 9± 14 6 5 ) %·年 1和 (13 5± 3 2 ) % ,P <0 0 1〕 ,骨髓脂肪组织面积F/TV由 (18 2± 5 6 ) %减少到 (11 4± 3 6 ) % (P <0 0 5 )。　结论　PGE2 在短期内有刺激老年大鼠松质骨成骨细胞骨形成 ,增加骨量的作用。     

老年糖尿病患者自由基与微血管并发症关系的探讨

目的　探讨老年糖尿病患者自由基和抗氧化能力的变化及其与微血管并发症的关系。　方法　测定 6 5例老年糖尿病患者和 6 5例健康老年对照者血浆或红细胞中脂质过氧化物 (LPO)、超氧化物岐化酶 (SOD)、过氧化氢酶 (CAT)、谷胱甘肽过氧化物酶 (GSH PX)、维生素C(VC)、维生素E(VE)、β 胡萝卜素 (β CAR)、谷胱甘肽 (GSH) ,同时测定患者的空腹血糖、餐后 2h血糖、糖化血红蛋白(HbA1c)、空腹和餐后 2hC肽、血脂、尿微量白蛋白排泄率、肌电图。　结果　老年糖尿病患者LPO(42 97± 6 99)nmol/g高于健康老年组 (31 5 9± 7 4 4 )nmol/g ,SOD(1712 4 4± 15 7 0 4 )U/L、CAT(2 17 0 1± 2 9 36 ) μg/g、GSH PX(2 1 0 1± 3 38)× 10 -10 U/RBC、VC(40 98± 10 5 1) μmol/L、VE(16 4 4± 2 4 5 ) μmol/L、β CAR(1 19± 0 2 3) μmol/L、GSH(0 98± 0 16 )nmol/L低于健康老年组〔分别为 (192 8 38± 14 3 4 4 )U/L、(2 6 4 4 0± 6 3 5 5 ) μg/g、(2 5 16± 6 4 1)× 10 -10 U/RBC、(5 2 2 3± 10 5 1) μmol/L、(2 3 0 4± 5 38) μmol/L、(1 6 3± 0 4 0 ) μmol/L、(1 2 5± 0 2 0 )nmol/L〕 ,合并糖尿病微血管并发症者变化更加明显 ,LPO和年龄呈正相关 (r=0 310 ,P <0 0 5 ) ,SOD、C     

HBVDNA的表达与肝纤维化形成的相关性研究

探讨HBVDNA的表达与肝纤维化形成的相关性。应用荧光定量PCR技术测定 2 0 0例乙肝患者和 4 9名健康对照组的血清HBVDNA ,同时用放免法检测层粘连蛋白 (LN)、透明质酸 (HA)、Ⅲ型前胶原 (PⅢ )、Ⅳ型胶原 (Ⅳ .C)水平。HBVDNA表达阳性组LN、HA、PⅢ、Ⅳ .C的含量〔(16 4 8± 5 6 1)、(16 6 1± 78 0 )、(15 3 5± 6 0 7)、(92 1±2 9 9) μg/L〕显著高于HBVDNA阴性组〔(110 9± 2 9 8)、(82 1± 2 4 7)、(91 9± 2 9 2 )、(5 9 5± 14 3) μg/L〕(P <0 0 0 1)和健康对照组〔(10 4 9± 16 3)、(6 8 0± 2 7 6 )、(76 3± 2 1 3)、(5 4 3± 7 8) μg/L〕(P <0 0 0 1)。HBVDNA阳性组中 ,上述四项指标随着HBVDNA含量升高而递增。动态观察 2 8例乙肝患者随着治疗过程HBVDNA浓度下降 ,LN、HA、PⅢ、Ⅳ .C的含量明显递减。HBVDNA的阳性表达与肝纤维化形成的相关性十分密切     

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.