老年大鼠松质骨骨重建的组织形态计量学研究

目的：研究老年大鼠及在促骨合成药前列腺素E2（PGE2）作用下松质骨骨重建和骨建造的形态计量学改变，探讨动物骨重建形态学新参数测量方法及其意义。方法：50只20月龄雄性Wistar大鼠随机分成5组，年龄对照组（基础组、10d和30d年龄对照组），PGE2给药组（分别10d和30d给予3mg/kg/d处理组）。用体内双荧光标记，不脱钙组织切片，粘合线（cement line）染色，骨组织形态计量学方法，测定骨重建和骨建造参数。结果：20月龄雄性大鼠胫骨近端松质骨的形成表面大多数为骨重建单位（占63．3％），少部分为骨建造单位（占26．7％）；PGE2用药后骨重建单位增加1．5倍，骨建造单位增加4倍，比值倒置，成骨细胞10d时明显增多。说明PGE2通过刺激成骨细胞骨合成而介民导骨建造性骨增加和骨重建性骨量增加，并以前为主。结论：老年雄性大鼠 松质骨以骨重建活动为主，仍有骨建造活动。PGE2主要通过刺激成骨细胞骨建造而增加骨量。     

A modified Ross operation to prevent pulmonary autograft dilatation.

A modification in Ross operation is described in which the free-standing pulmonary autograft root is suspended in a Dacron prosthetic vascular jacket with a view to prevent dilatation of the neo-aortic root. In a group of 13 patients operated consecutively using this technique, there was no significant increase in the diameters of the neo-aortic root after a mean 16-month follow-up. Aortic valve function remained also satisfactory.     

Unintended consequences of policy change to watchful waiting for asymptomatic inguinal hernias

Introduction

In 2009 the Department of Health instructed McKinsey & Company to provide advice on how commissioners might achieve world class National Health Service productivity. Asymptomatic inguinal hernia repair was identified as a potentially cosmetic procedure, with limited clinical benefit. The Birmingham and Solihull primary care trust cluster introduced a policy of watchful waiting for asymptomatic inguinal hernia, which was implemented across the health economy in December 2010. This retrospective cohort study aimed to examine the effect of a change in clinical commissioning policy concerning elective surgical repair of asymptomatic inguinal hernias.

Methods

A total of 1,032 patients undergoing inguinal hernia repair in the 16 months after the policy change were compared with 978 patients in the 16 months before. The main outcome measure was relative proportion of emergency repair in groups before and after the policy change. Multivariate binary logistic regression was used to adjust the main outcome for age, sex and hernia type.

Results

The period after the policy change was associated with 59% higher odds of emergency repair (3.6% vs 5.5%, adjusted odds ratio [OR]: 1.59, 95% confidence interval [CI]: 1.03–2.47). In turn, emergency repair was associated with higher odds of adverse events (4.7% vs 18.5%, adjusted OR: 3.68, 95% CI: 2.04–6.63) and mortality (0.1% vs 5.4%, p<0.001, Fisher’s exact test).

Conclusions

Introduction of a watchful waiting policy for asymptomatic inguinal hernias was associated with a significant increase in need for emergency repair, which was in turn associated with an increased risk of adverse events. Current policies may be placing patients at risk.     

MRI and plain radiography in the assessment of displaced fractures of the waist of the carpal scaphoid

We treated 50 patients with fractures of the waist of the scaphoid in a below-elbow plaster cast for up to 13 weeks. Displacement of the fragments was assessed independently by two observers using MRI and radiographs performed within two weeks of injury. The MRI assessments showed that only the measurement of sagittal translation of the fragments and an overall assessment of displacement had satisfactory inter- and intra-observer reproducibility and revealed that nine of the 50 fractures were displaced. Only three of the 49 fractures with adequate follow-up failed to unite, and all were displaced with more than 1 mm of translation in the sagittal plane. If the MRI assessment of displacement of the fracture was used as the measurement of choice, assessment of displacement on the initial scaphoid series of radiographs showed a sensitivity of between 33% and 47% and a positive predictive value of between 27% and 86%. Neither observer was able correctly to identify more than 33% to 47% of the displaced fractures from the plain radiographs. Although the overall assessment of displacement and gapping and translation in the coronal plane on the plain radiographs influenced the rate of union, none of these parameters identified all three fractures which failed to unite. We conclude that the assessment of displacement of scaphoid fractures on MRI can probably be used to assess the likelihood of union although the small number of nonunions limits the power of the study. In contrast, the assessment of displacement on routine radiography is inaccurate and of less value in predicting union.     

Reversible oxidant-induced increases in albumin transfer across cultured endothelium: alterations in cell shape and calcium homeostasis

To determine whether reactive oxygen molecules could directly and reversibly increase the transfer of albumin across an endothelial barrier, we measured albumin transfer across monolayers of endothelium cultured on micropore filters before and after exposure to xanthine and xanthine oxidase. Xanthine and xanthine oxidase increased endothelial albumin transfer in a dose-dependent fashion. Parallel phase contrast and fluorescence microscopy demonstrated retraction of adjacent cells from one another and disruption of the actin filaments. The oxidant- induced increases in albumin transfer and changes in cell shape were reversed by removing xanthine oxidase and then incubating the monolayers for 3 1/2 hours in tissue culture media enriched with fetal bovine serum. However, incubation in tissue culture media without serum resulted in progressive injury and cell death. Hence, the brief exposure to oxidants initiated a progressive injury process that was reversed by incubation in serum. Because intracellular and extracellular calcium are important determinants of cell shape, and because some oxidized membrane lipids act as calcium ionophores, we asked whether oxidants altered endothelial calcium homeostasis. Xanthine-xanthine oxidase increased release of 45Ca++ from preloaded cells. The calcium antagonist lanthanum chloride prevented xanthine- xanthine oxidase increases in endothelial albumin transfer and prevented the changes in cell shape; chelation of extracellular calcium inhibited lysis of endothelium by xanthine-xanthine oxidase; and the calcium ionophore A23187 increased endothelial albumin transfer and mimicked the oxidant-induced changes in cell shape. Lanthanum chloride inhibited these effects of A23187. These data suggest that oxygen radicals can reversibly increase endothelial permeability to macromolecules, that this is associated with reversible changes in endothelial cell shape and actin filaments, and that the changes in cell shape are related to oxidant-induced changes in endothelial calcium homeostasis.     

Bilateral simultaneous laparoscopic adrenalectomy in Cushing's syndrome: safe, effective, and curative

INTRODUCTION: Surgical morbidity and mortality rates are high in patients with Cushing's syndrome. Nevertheless, simultaneous bilateral laparoscopic adrenalectomy (LA) is feasible in these patients with less morbidity and good long-term results. BACKGROUND AND RESULTS: Consecutive 22 patients who underwent LA for Cushing's syndrome between 2003 and 2010 in our institute were retrospectively studied. Ninteen patients underwent bilateral simultaneous and three underwent unilateral LA. Seven patients had Cushing's syndrome after failed pituitary surgery and five each had ectopic adrenocorticotrophic hormone dependent syndrome and bilateral macronodular hyperplasia respectively. LA was bilaterally done by lateral transabdominal adrenalectomy in 15 patients and retroperitoneal endoscopic adrenalectomy in 4 on the right side. Mean operative time for simultaneous bilateral cases was 199.45±72.43 minutes with mean blood loss of 72.72±48.6 mL. Patients were fit for discharge by the fifth postoperative day from the surgical aspect. Surgical complication rate was 26% that included wound infections in two, port site hernia, pleural effusion, and atelectasis in one each. One patient died of sepsis (5% mortality). Satisfactory metabolic control was achieved in all observable patients in the long term although Addisonian crisis and Nelson syndrome were seen in 26% and 15% respectively. CONCLUSION: LA has all advantages of minimal access surgery in patients with Cushing's syndrome who are immunocompromised and at high risk of delayed wound healing and infections. Magnification decreases the risk of retained adrenal remnants. Despite advances in minimal access surgery, perioperative morbidity continues to be significant for the procedure.     

The effect of patellar replacement technique on patellofemoral complications and anterior knee pain

Routine patella replacement with total knee arthroplasty has not been universally adopted because of associated patellofemoral complications such as anterior knee pain (AKP). In the proposed technique, the articular surface of the lateral facet of the patella is excised to the depth of the subchondral bone, and the medial facet is then cut parallel to the anterior surface. We evaluated any correlation between various radiographic parameters and AKP in 100 consecutive fixed-bearing posterior-stabilized total knee arthroplasties. There were no cases of fracture, avascular necrosis, subluxation, dislocation, patellar baja, or overstuffing of the patella. Anterior knee pain was present in 11% of cases, and no cases were severe or disabling. There were no correlations between AKP, range of motion, patellar size and shape, and any of the radiographic parameters.     

Colorectal Cancer: Postoperative Follow-up and Surveillance

Follow-up and surveillance form an important aspect of care in patients with colorectal cancers (CRC). Most recurrences will occur within 2 years of surgery and 90% by 5 years. Follow up protocols have not been well defined in stage I disease and the approach should be individualized. As 40% of patients with stages II and III will develop recurrences, intensive postoperative follow-up strategy is recommended for them. It includes visit to the clinician for clinical examination, serum carcinoembryonic antigen (CEA), computed tomography (CT) of the chest and abdomen, colonoscopy, and flexible proctosigmoidoscopy in rectal cancers. Surveillance should be undertaken in those who are medically fit for repeat surgical procedures or for chemoradiotherapy. The concept of intensive post operative surveillance is based on the fact that some of these patients can have resectable/curable recurrence.