腹腔镜胆囊切除术前超声内镜检查胆总管必要性的探讨

目的 探讨腹腔镜胆囊切除（laparoscopic cholecystectomy,LC）术前超声内镜（endoscopic ultrasonography,EUS）检查胆总管的临床价值。方法 对25例术前经腹超声检查诊断胆囊结石,胆总管内径〉0.7 cm可疑胆总管梗阻的患者进行EUS检查,并与手术结果或内镜十二指肠乳头切开术（endoscopic sphincterotomy,EST）取石结果进行比较。结果 EUS对于胆总管病变诊断的敏感性、准确性和阴性预测值[100%（17/17）、92%（23/25）、100%（6/6）]均优于经腹超声[35%（6/17）、56%（14/25）、42%（8/19）]（P=0.000,0.008,0.020）。结论EUS对胆总管病变诊断优于经腹超声检查,可作为术前常规检查,特别是当胆总管内径〉1.0 cm时,EUS应作为术前必检项目。     

胆囊鳞癌6例报告

目的：探讨胆囊鳞癌的发病情况、特点、诊断、治疗、预后及预防。方法：结合有关文献复习分析6例胆囊鳞癌的病例。结果：5例行手术治疗，术后两月内死亡3例，另两例至今存活，分别为术后8个月，3个月。1例行B超引导穿刺活检，入院后两周死亡。结论：胆囊鳞癌早期无特异症状，诊断时多已属晚期，手术效果较差。早期诊断、根治性手术有助于胆囊鳞癌的预后。     

Inhibitory effect of bikunin on calcium oxalate crystallization in vitro and urinary bikunin decrease in renal stone formers

Two proteins of 17 and 24 kDa, respectively, which were immunologically related to bikunin, were purified from urine of healthy men, using in the last step a trypsin CNBr-sepharose affinity column. These proteins strongly inhibited calcium oxalate (CaOx) crystallization in two in vitro models. In the first model, the presence of 8 μg/ml protein in a medium containing 0.76 mM CaCl₂ (with ⁴⁵Ca) and 0.76 mM ammonium oxalate inhibited the crystallization process by 80%, as estimated by supernatant radioactivity after 60 min of incubation. A similar inhibition was observed in the second turbidimetric model, where the CaOx crystallization kinetics were followed for 10 min at 620 nm in a medium containing 4 mM CaCl₂ and 0.5 mM Na₂Ox. These proteins were used as standard protein for the development of an enzyme-linked immunosorbent assay (ELISA) in urine. Mean (± SEM) urinary bikunin concentration in 18 healthy subjects was 5.01 ± 0.91 μg/ml. This was a concentration range of strong inhibitory activity in vitro. Bikunin values were nearly 50% lower (2.54 ± 0.42 μg/ml, P=0.007) in 31 CaOx renal stone formers (having weddelite crystals in their first morning urine) than in the healthy volunteers. A correlation was found between urinary bikunin and alpha-1 microglobulin concentrations in the control group (y=0.73x + 1.09, r ²=0.8) while no such correlation existed in the lithiasis group. In conclusion, bikunin exerts a strong inhibitory action of CaOx crystallization in vitro. Its involvement in urinary CaOx crystallization of stone formers is highly probable, based on the significant decrease in its urinary concentration in the majority of stone formers studied. Received: 16 December 1997 / Accepted: 23 June 1998     

Crystalluria in marathon runners

Summary In order to investigate further the possible relationship between urinary stone formation and marathon running, the crystalluria in seven male, stone forming runners was characterized. Particle size distribution curves (Coulter counter) and crystal number, size and morphology (scanning electron microscopy) were measured. These studies suggest that urinary stone formation may be accelerated in those subjects with previous histories of renal stone formation but that the nature of the crystalluria is favourably affected by an increase in fluid intake. The presence of large quantities of mucoid material in the urine of natural stone formers and its absence in the urine of stone-forming runners is cited as evidence for the existence of different aetiological mechanisms in these groups. It is concluded that while natural stone formers may be at chronic risk of stone formation due to pathological factors, marathon runners may be at acute risk due to factors associated with long distance running itself.     

Loss of regulation of circulating 1,25-dihydroxyvitamin D with paradoxically decreased serum phosphate levels in individuals with recurrent kidney stones

A low serum phosphate concentration is characteristic in individuals in whom kidney stones form, this being related to serum 1,25-dihydroxyvitamin D, parathyroid hormone and urinary phosphate excretion. In order to determine whether these parameters are related to recurrence of stone formation, they were analyzed in single and recurrent stone formers as well as controls. An inverse correlation between serum levels of phosphate and 1,25-dihydroxyvitamin D was observed in control subjects, indicating that a drop in serum phosphate results in upregulated circulating 1,25-dihydroxyvitamin D level in controls. While the circulating low phosphate level upregulated the 1,25-dihydroxyvitamin D level in single stone formers, the elevation was less than expected from the drop in serum phosphate in recurrent stone formers. The results thus suggest that loss of upregulation of 1,25-dihydroxyvitamin D by serum levels of phosphate might be important for stone formation. The possibility of deregulation of 1,25-dihydroxyvitamin D to maintain physiological requirements in stone formers and prevent further nephrolithiasis therefore warrants attention. Received: 27 January 1999 / Accepted: 25 June 1999     

A humid corridor across the Sahara for the migration of early modern humans out of Africa 120,000 years ago

It is widely accepted that modern humans originated in sub-Saharan Africa approximately 150-200 thousand years ago (ka), but their route of dispersal across the currently hyperarid Sahara remains controversial. Given that the first modern humans north of the Sahara are found in the Levant approximately 120-90 ka, northward dispersal likely occurred during a humid episode in the Sahara within Marine Isotope Stage (MIS) 5e (130-117 ka). The obvious dispersal route, the Nile, may be ruled out by notable differences between archaeological finds in the Nile Valley and the Levant at the critical time. Further west, space-born radar images reveal networks of-now buried-fossil river channels that extend across the desert to the Mediterranean coast, which represent alternative dispersal corridors. These corridors would explain scattered findings at desert oases of Middle Stone Age Aterian lithic industries with bifacial and tanged points that can be linked with industries further to the east and as far north as the Mediterranean coast. Here we present geochemical data that demonstrate that water in these fossil systems derived from the south during wet episodes in general, and penetrated all of the way to the Mediterranean during MIS 5e in particular. This proves the existence of an uninterrupted freshwater corridor across a currently hyperarid region of the Sahara at a key time for early modern human migrations to the north and out of Africa.     

石雕作业职业病危害因素对小鼠学习记忆能力的影响及其作用机制

目的探讨石雕作业职业病危害因素对小鼠学习记忆能力的影响及其机制。方法将60只昆明种小鼠随机分为对照组(无暴露)、低暴露组(暴露时间2 h/d)、中暴露组(4 h/d)和高暴露组(8 h/d)。同时测量该作业环境中粉尘浓度、噪声、气温以及作业时工人手臂接触振动的强度等职业病危害因素。15 d后,用Y迷宫测小鼠学习记忆能力,测其脑组织中一氧化氮(NO)含量和一氧化氮合酶(NOS)、三磷酸腺苷(ATP)酶活力。结果石雕作业环境中的粉尘浓度为34.00~125.33 mg/m3,噪声强度为90.0~104.0 d B(A),振动强度ahw(4)为8.3~10.5 m/s2,平均温度为32.0~32.7℃。小鼠学习能力和记忆能力低暴露组与对照组差异无统计学意义,中暴露和高暴露组均低于对照组(P0.05)。与对照组比较,暴露组NO含量(F=4.312,P0.05)、NOS活力(F=3.937,P0.05)和ATP酶活力明显降低[Na+K+-ATP酶活力(F=3.890,P0.05)、Ca2+Mg2+-ATP酶活力(F=3.893,P0.05)],且高暴露组降低更明显。结论石雕作业环境中的职业病危害因素的共同作用降低了小鼠的学习、记忆能力,该作用可能与NO含量的降低,NOS、ATP酶活力的抑制有关。     

Efficacy of nifedipine therapy for refractory angina pectoris

Nifedipine is a calcium-channel blocking agent that has been effective for patients with angina pectoris when used as single-agent therapy and as part of a combination regimen with conventional antianginal therapy. However, the efficacy of nifedipine in patients with angina refractory to maximum tolerated conventional therapy has not been extensively studied. We present experience using nifedipine in the treatment of three distinct subsets of patients with refractory angina pectoris. One hundred twenty-seven patients with Prinzmetal's variant angina and documented coronary vasospasm were treated with nifedipine after experiencing an inadequate response to conventional therapy. Nifedipine, 40 to 160 mg daily, reduced the mean weekly rate of angina attacks from 16 to 2 (p < 0.001). In 63% of the patients complete control of angina attacks was achieved, and in 87% the frequency of angina was reduced by at least 50%. Nifedipine therapy was well tolerated, and the beneficial response persisted for the 9 months of follow-up. Nifedipine therapy was added to a second group of 11 consecutive patients with refractory episodes of recurrent rest ischemia following acute myocardial infarction. Prior to infarction all the patients had a history of exertional angina only; yet following the infarction, episodes of recurrent ischemia occurred at rest in spite of maximal medical management with beta blockers and/or nitrate preparations. With maximum tolerated conventional therapy the heart rate was lowered to a mean of 65 beats/min and the blood pressure to a mean of $\text{109}\text{70}\text{mm Hg}$. The episodes of rest ischemia were prevented in all but one patient by the addition of nifedipine (mean daily dose 60 mg, range 40 to 120 mg) without causing a change in heart rate or blood pressure. Two patients continued to have myocardial ischemia with minimal exertion, although resting pains were abolished, and they underwent coronary bypass surgery for rellef of exertional pain. Only one patient continued to have episodes of ischemia at rest, and bypass surgery was necessary for pain relief. The other eight patients have been managed medically for a mean of 5.4 months and have remained pain free on combined regimens of nifedipine, beta blockers, and/or nitrate preparations. The third group of patients treated with nifedipine is composed of 239 patients with severe classic exertional angina pectoris without a suspicion of superimposed coronary vasospasm. The anginal episodes in these patients were refractory to maximum tolerated conventional therapy; however, the addition of nifedipine (mean daily dose 60 mg, range 40 to 120 mg) reduced the mean weekly angina attack rate from 20.8 to 6.4 (p < 0.00001). Although only 11% of patients had complete prevention of angina during nifedipine therapy, a total of 70% experienced a reduction in angina frequency of at least 50%. We conclude that the addition of nifedipine therapy may provide further benefit for patients with angina pectoris refractory to maximum tolerated conventional therapy. Randomized, placebo-controlled studies are necessary to confirm the efficacy of nifedipine therapy in patients with refractory angina and to clarify the mechanism of the beneficial response.