Negative charge distribution and density on the surface of oxygenated normal and sickle red cells

Negative charges on the external surface of red cells were visualized by colloidal iron hydroxide labelling of 50% of the membrane area after osmotic hemolysis and glutaraldehyde fixation. Counts were made over randomly selected areas on electron micrographs at 350,000 x magnification. Statistical analyses showed that at the 95% level of confidence there was no significant difference between oxygenated normal (AA) and sickle (SS) cells in either the distribution or the density of negative charges.     

Teaching the teachers: helping faculty in a family practice residency improve their informatics skills.

Faculty members in family practice residencies are increasingly being asked to help residents develop skills in the use of informatics and evidence-based medicine (EBM). In order to do this successfully the teachers themselves must be skilled in the use of these tools. Recognizing the need for such training, the Maine Medical Center Family Practice Residency Program designed a faculty development project to increase knowledge and skills in the use of information technology. This project, which was carried out in 1999-2001, utilized a multifaceted approach that included improving the residency's technology infrastructure, conducting two instructional workshops, and offering EBM mentoring for preceptors. Faculty members also designed and carried out independent informatics projects. Pre- and post-project assessments of faculty members demonstrated a significant improvement in computer and EBM skills, and informal feedback from residents indicates that these skills have been successfully applied to the faculty members' teaching of residents and their practice of family medicine. This project had a positive impact on the faculty members in the residency program, increasing both their ability to employ information technology in individual and group teaching sessions and their use of EBM in clinical practice. Also, the culture within the residency program has been changed to one of utilizing computers and the Internet as principal resources for up-to-date information.     

Serum concentrations of oestradiol-17beta, progesterone, relaxin and chorionic gonadotrophin during blastocyst implantation in natural pregnancy cycle and in embryo transfer cycle in the rhesus monkey

The present study was undertaken to assess the temporal association between the profiles of serum concentrations of oestradiol-17beta, progesterone, chorionic gonadotrophin (CG) and relaxin in pregnancies established naturally, and after embryo transfer, as well as in failed pregnancies in rhesus monkeys. In naturally mated cycles (group 1) a conception rate of 75% was obtained. In group 1, the mean day of CG detection in serum was 11.5 +/- 1.9 day post-ovulation, and for relaxin, 9.0 +/- 2.5 day post-ovulation. In group 2, embryo transfer to synchronous, non-mated surrogate recipients was performed; seven embryo transfer cycles yielded three pregnancies which were allowed to continue to term and normal infants were delivered. In embryo transfer cycles the mean day of CG detection was 14.8 +/- 1.8 day post- ovulation, and for relaxin, 11.4 +/- 2.6 day post-ovulation. A delay of about 3 days was observed in the appearance in circulation of CG (P < 0.05) and also of relaxin (P < 0.05) between natural mated and embryo transfer conception cycles. Significant differences (P < 0.05 for progesterone and P < 0.03 for oestradiol) were obtained for the areas under the curves for progesterone and oestradiol between days 12 and 16 in conception cycles compared with failed pregnancies. These data provide the first observation of the normal hormonal signals associated with maternal recognition of transferred embryos during the peri- implantation period, and suggest that the use of such an experimental primate embryo transfer model may help to elucidate components of maternal and embryonic signal-response mechanisms during embryo implantation.      

肝细胞生长因子诱导实验性视网膜脱离的病理机制研究

目的 观察肝细胞生长因子（HGF）对视网膜色素上皮（RPE）细胞屏障功能的影响以及RPE内过度表达HGF导致视网膜脱离（RD）的病理机制。 方法 编码HGF（AdCMV.HGF）、绿色荧光蛋白（Ad CMV.GFP）的E1/E3缺失的腺病毒载体，以5×10⁴ 噬斑形成单位（pfu）/眼注射到成年有色兔的视网膜下。检查注射后3、7、14、28 d时的眼底及组织病理变化,利用免疫组织化学和酶联免疫吸附试验（ELISA）方法检测HGF在视网膜和玻璃体的表达水平。 结果 对照组注射Ad CMV.GFP眼显示GFP几乎仅表达于PRE单核细胞层，AdCMV.HGF注射眼在注射点处的PRE细胞出现强的HGF免疫阳性反应。玻璃体内HGF的表达水平在注射7 d后达到最高峰、28 d后降低到基础水平。在HGF的表达期内AdCMV.HGF注射眼出现慢性RD和脉络膜慢性炎症。在RD区域，视网膜下的空间内可见增生性的RPE细胞，部分实验兔眼还产生多层的细胞膜结构。 结论 RPE内过度表达的HGF能引发慢性浆液性RD，同时伴有视网膜下RPE增生。提示HGF可能作为治疗RD的作用靶点。(中华眼底病杂志，2007，23：193-197)     

Role of venous drainage in cerebral arteriovenous malformation surgery,as related to the development of postoperative hyperperfusion injury

OBJECTIVE: To elucidate the role of venous drainage in cerebral arteriovenous malformation (AVM) surgery, with respect to the development of postoperative hyperperfusion injury. METHODS: For 52 patients with supratentorial AVMs, cortical capillary oxygenation (SaO(2)) was assessed intraoperatively, before and after resection, in the vicinity of the AVMs, by using a microspectrophotometric method. Assessed areas were defined as being related to feeding arteries or draining veins or as distant areas. Patients were divided into three groups on the basis of postoperative angiographic findings, as follows: Group 1, all former draining veins preserved (8 patients); Group 2, > or =1 former draining vein visible (12 patients); Group 3, no former draining veins visible (32 patients). Patients and SaO(2) values were pooled and compared by using paired and unpaired t tests (P < 0.05). Venous circulation times were calculated from digital subtraction angiography films. RESULTS: The postresectional relative increases in SaO(2) values were highest in draining vein areas (+40.8%, compared with +25% in feeder areas and +25.5% in distant areas). Five postoperative hyperemic complications occurred (9.6%), none in Group 1 (with all draining veins preserved), two (16.7%) in Group 2, and three (9.4%) in Group 3 (with all draining veins occluded). The lowest preresectional SaO(2) values (31.7 +/- 6.2%) were measured in the drainer areas of the five patients who subsequently developed hyperperfusion injuries. Among those patients, postresectional increases in SaO(2) values were significantly greater in drainer areas (+167.8%) than in feeder areas (+28.3%) or distant areas (+25.8%). Postoperative venous circulation times in former draining veins in Group 2 were significantly greater than those in Group 1 (8.9 +/- 1.5 s versus 6.3 +/- 0.6 s). Circulation times in normal veins in the five patients with hyperperfusion injury increased from 5.6 +/- 1.0 seconds (preoperatively) to 8.4 +/- 1.9 seconds (postoperatively). CONCLUSION: Postoperative hyperperfusion injury after resection of cerebral AVMs can be explained on the basis of unconstrained arterial inflow into cortical areas, which are rendered hypoxic/ischemic by longstanding preoperative venous hypertension. The risk for postoperative breakthrough complications seems higher in the presence of multiple draining veins, which also participate in the physiological venous drainage system of the ipsilateral hemisphere.     

Laparoscopic Roux-en-Y gastric bypass for severe gastroesophageal reflux after vertical banded gastroplasty

Background: Vertical banded gastroplasty (VBG) is sometimes associated with complications such as pouch obstruction, dilatation, and gastroesophageal reflux. This occasionally requires surgical revision, in many cases to a Roux-en-Y gastric bypass (RYGBP). Case Report: A 47-year-old woman with severe obesity developed severe symptoms of stenosis of the pouch outlet and gastroesophageal reflux 15 years after VBG. Laparoscopic conversion to a RYGBP was performed. At 9-month follow-up, she lost an additional 32 kg and had complete resolution of her reflux. Conclusion: In this patient, laparoscopic re-operative RYGBP produced additional weight loss, and improved gastroesophageal reflux that occurred many years after having a VBG. Laparoscopic conversion of a VBG to RYGBP is feasible, and may confer the benefits of other minimally invasive abdominal procedures to this high-risk patient group.     

Cognitive performance and magnetic resonance imaging findings after high-dose systemic and intraventricular chemotherapy for primary central nervous system lymphoma

BACKGROUND: Long-term neurotoxicity is a frequent complication of combined radiotherapy and chemotherapy in patients with primary central nervous system lymphoma. Treatment protocols without radiotherapy have been implemented to avoid this; however, little detailed neuropsychologic and neuroradiologic data exist to assess the frequency of long-term treatment sequelae in this patient group. OBJECTIVE: To determine whether a polychemotherapy regimen based on high-dose methotrexate results in cognitive impairment and/or changes detectable by magnetic resonance imaging of the brain during long-term follow-up. PATIENTS AND METHODS: Twenty patients with histologically proven primary central nervous system lymphoma were treated with a novel chemotherapy protocol that included systemic and intraventricular administration of methotrexate and cytarabine (ara-C). Standardized neuropsychologic testing and magnetic resonance imaging investigations were performed prior to therapy and prospectively during a median follow-up period of 36 months (range, 21-69 months). RESULTS: Ten patients achieved durable remissions without relapse for more than 1 year after completion of chemotherapy. There was no gross cognitive decline in any of these patients during the follow-up period. In contrast, magnetic resonance imaging revealed therapy-induced white matter changes in 5 of these patients. CONCLUSIONS: We conclude that chemotherapy alone is associated with a low risk of long-term neurotoxicity in primary central nervous system lymphoma. Methotrexate-induced white matter lesions detectable on magnetic resonance imaging are not inevitably associated with significant cognitive decline.     

Focal cortical dysplasia of Taylor's balloon cell type: a clinicopathological entity with characteristic neuroimaging and histopathological features, and favorable postsurgical outcome

BACKGROUND AND PURPOSE: Focal cortical dysplasia of Taylor's balloon-cell type (FCD-BC) are a frequent cause of pharmacoresistant epilepsy in young patients. In order to characterize FCD-BC, we coupled MRI and histopathology, and analyzed the clinical outcome following epilepsy surgery. METHODS: From an epilepsy data bank with 547 histological specimens, 17 FCD-BC were re-evaluated of which high resolution MRI was available. Five additional FCD-BC were prospectively identified by MRI. Histopathological and immunohistochemical features were related to MRI. Outcome following lesionectomy was analyzed as determined on routine examinations 3, 6 and 12 months following surgery. RESULTS: All but one lesion were located outside the temporal lobe. A markedly hyperintense funnel-shaped subcortical zone tapering towards the lateral ventricle was the characteristic finding on FLAIR MRI. Histopathologically, the subcortical zone of the FCD-BC displayed hypomyelinated white matter with radially oriented balloon cells and gliosis. Dysplastic neurons were found in the adjacent, disorganized cortex. All patients with complete lesionectomy were seizure free one year following surgery. CONCLUSION: Focal cortical dysplasias of Taylor's balloon-cell type (FCD-BC) have characteristic MRI and histopathological findings. MRI recognition is important, since outcome following resective surgery is favorable.