Do first- and second-year preclinical course scores predict student performance during the surgical clerkship?

The study proposed to determine if a preclinical basic science index comprised of anatomy, behavioral medicine, biochemistry, microbiology, pathology, pharmacology, and physiology courses or any one of these basic science courses would predict student performance during surgical clerkship. The basic science index demonstrated a correlation of 0.55 and 0.35 with the individual student's written and oral clerkship scores, respectively. A stepwise multiple regression using a backward stepping algorithm was applied; the dependent variables were oral and written clerkship scores, and the independent variables were the basic science courses. Microbiology, pathology, and physiology course scores were predictors of written score (R = 0.60). Pathology course scores were the sole predictor of oral score (R = 0.43). Medical student basic science performance was not a strong forecaster of performance on the surgical clerkship. The pathology basic science score was the only consistent predictor of performance on the written and oral evaluations given at the end of the clerkship.     

Bioavailability of zinc to rats as affected by protein source and previous dietary intake

The bioavailability of zinc from defatted soy flour, dried chicken meat or mixed (50:50 dry weight basis) soy flour and chicken meat included in egg white-based diets was investigated in rats. Following a 6-d experimental diet (9 ppm Zn) feeding period, marginally zinc-depleted weanling rats were fed a test meal, identical in composition to the experimental diet except that the protein source was labeled either intrinsically or extrinsically with 65Zn. Retention of 65Zn from the chicken test meal was significantly higher than that from the soy test meal. Retention of 65Zn from the mixed soy/chicken test meal was midway between the retention values for either protein alone regardless of which protein source was labeled. Intrinsic and extrinsic labeling techniques resulted in similar assessment of zinc bioavailability. Additionally, the influence of previous dietary protein source on zinc retention from a soy test meal was investigated. Retention of 65Zn from an intrinsically labeled soy test meal was higher in rats adapted to chicken protein than in rats adapted to soy protein. The levels of tibia zinc and tibia 65Zn were associated with whole-body retention of 65Zn.     

Melatonin receptors and signal transduction during development in Siberian hamsters (Phodopus sungorus).

Maternal melatonin communicates daylength information to the fetus in Siberian hamsters. Fetal sensitivity to melatonin declines near birth. In this report, we describe melatonin receptor distribution and a second messenger response to melatonin in Siberian hamsters during the perinatal period. The sites of high-affinity 2-[125I]iodomelatonin ([125I]MEL) binding were generally similar throughout the perinatal period. The non-hydrolyzable GTP analog, guanosine-5'-O-(3-thiotriphosphate) (100 microM) inhibited [125I]MEL binding at each age, suggesting the melatonin receptors are associated with guanine nucleotide binding proteins (G proteins). Furthermore, melatonin (10 nM) inhibited forskolin-stimulated cAMP accumulation in median eminence/pars tuberalis (ME/PT) explants as early as 4 days before birth, when sensitivity to melatonin in vivo is high. The cAMP regulatory system appeared disrupted on the day of birth, in that forskolin (10 microM) stimulation of cAMP accumulation was reduced, and melatonin did not inhibit cAMP accumulation stimulated by forskolin. A higher forskolin dose (100 microM) elevated cAMP levels more clearly on the day of birth, and melatonin inhibited forskolin-stimulated cAMP accumulation. These results suggest that the decreased physiological responsiveness to melatonin at the end of gestation may be due to alterations in the cAMP regulatory system.     

The relative utilization of eicosapentaenoic and arachidonic acids by the 1-acylgycerophosphorylcholine and the 1-acylglycerophosphorylinositol acyltransferase pathways in human platelet microsomes

The relative entry of eicosapentaenoic acid (EPA) and arachidonic acid (AA) via 1-acylglycerophosphorylcholine and 1-acylglycerophosphorylinositol acyltransferase activity into phosphatidylcholine (PC) and phosphatidylinositol (PI), respectively, was studied in human platelets. A known mixture of [¹⁴C]EPA and [³H]AA along with an acyl-CoA generating system and lyso-acceptor phospholipids were incubated with a platelet mixed membrane preparation. The radioactivities in the products were determined following lipid extraction and thin-layer chromatographic separations. The [³H]AA/[¹⁴C]EPA ratios in the products, PC and PI, indicated some preference of both acyltransferase pathways for EPA over AA at 50 μM exogenously-added lysoPC or lysoPI. Altering the concentration of lysoPC (10–50 μM) did not significantly affect the selectivity for EPA. In contrast, reducing the concentration of lysoPI from 50 μM to 10 μM changed the selectivity of the acyltransferase pathway from favouring EPA to slightly favouring AA. The presence of a mixture of lysoPC and lysoPI resulted in a partitioning of EPA more towards PC and less towards PI which may account, in some part, for the greater AA/EPA mass ratio observed in the PI from human subjects consuming fish oil. The magnitude of the differences between PC and PI in their AA/EPA mass ratios observed in vivo, however, cannot be explained by the selectivity demonstrated herein by the acyltransferase pathways.     

Multiple evanescent white dot syndrome

Three patients had documented fundus changes conforming to those of the recently described multiple evanescent white dot (MEWD) syndrome. All three patients were unilaterally affected with variously sized, soft, single, and coalescent white lesions at the level of the RPE and the deep retina. Fluorescein angiography demonstrated early staining and hyperfluorescence of the white dots and delayed staining around the optic disc. Some degree of optic disc edema could be seen in all three eyes, two of which had corresponding field defects. In all three eyes, characteristic "stippling," or granularity, of the affected macula developed rapidly and vitreal cells were observed. One eye had signs of previous perivascular inflammation. ERG studies performed on one patient indicated a reduction in the a-wave and depression of the ERP, findings that correlated with the clinical observations of RPE affectation.     

Physiological and psychological variables related to functional status in chronic obstructive pulmonary disease.

The relationship of selected physiological and psychological variables to functional status in patients with chronic obstructive pulmonary disease (COPD) was investigated in this study. There has been limited exploration of the relative contribution of these variables to the performance of activities of daily living in this population. A convenience sample of 104 outpatients with COPD participated in the study. The independent variables were causal attributions, depressed mood, self-esteem, pulmonary function, and exercise capacity, and the dependent variable was functional status. There was a significant difference in functional status between those who did and those who did not ask the question, "Why me?" (p = .03). In addition, the remaining psychological variables and both physiological variables were significantly correlated with functional status (p less than or equal to .01). To identify the combination of study variables most predictive of functional status a multiple regression analysis was performed. The combined variables of exercise capacity and depression best predicted functional status (p less than .0001). It is concluded that both physiological and psychological factors are important in understanding functional status in this population.     

A behavioral group procedure for parents of severely troubled and troubling youth in out-of-home care: Alternative to conventional parent training

Many youth, their parents, and social services regard the unification of the family as the most desirable outcome for youth in out-of-home placements. This goal is often difficult to achieve because the families of these troubled/troubling youths are often severely dysfunctional, with multiple problems. A group process model for serving natural parents of youth in placement is described which, in conjunction with one-on-one interactions with professionals, appears to have a positive impact on these families and on youths' return home. Group components that seem particularly important are described, including attendance by invitation only, public commitment to attend and participate, reminder prompts, transportation support, babysitting support, refreshments, opportunity to visit with their child, defined staff roles, an empowering approach, and starting where the parent is. The group process maintained a relatively high level of both attendance and participation by the targeted parents. Participants tended to achieve most goals that they set in the group. Our experience indicates that interventions with natural parents of troubled youth can enable even a very dysfunctional family to improve enough to receive youth back into their home.The authors are grateful for the assistance of Sharon Estill, Jim Bernardo, Anita Mentzer, Dave Walker, and Suni Dague-Lyman for assistance in collecting the data reported here. Debbie Buchanan and others have been a great assistance in transporting families.     

Costello syndrome: Clinical phenotype,genotype, and management guidelines

Costello syndrome (CS) is a RASopathy caused by activating germline mutations in HRAS. Due to ubiquitous HRAS gene expression, CS affects multiple organ systems and individuals are predisposed to cancer. Individuals with CS may have distinctive craniofacial features, cardiac anomalies, growth and developmental delays, as well as dermatological, orthopedic, ocular, and neurological issues; however, considerable overlap with other RASopathies exists. Medical evaluation requires an understanding of the multifaceted phenotype. Subspecialists may have limited experience in caring for these individuals because of the rarity of CS. Furthermore, the phenotypic presentation may vary with the underlying genotype. These guidelines were developed by an interdisciplinary team of experts in order to encourage timely health care practices and provide medical management guidelines for the primary and specialty care provider, as well as for the families and affected individuals across their lifespan. These guidelines are based on expert opinion and do not represent evidence‐based guidelines due to the lack of data for this rare condition.     

川芎嗪诱导大鼠骨髓间质干细胞分化为神经元样细胞的研究

目的用川芎嗪(ligustrazin hydrochloride)在体外定向诱导SD青年鼠骨髓间质干细胞(mesenchymal stem cells，rMSCs)分化为神经元样细胞。方法用低糖DMEM冲洗骨髓腔，收集骨髓细胞悬液，接种在塑料培养瓶中。经体外扩增、纯化，选用第5代后的骨髓间质干细胞进行诱导分化。用10μg／LbFcF预诱导24h，更换成含川芎嗪的无血清培养基DMEM诱导间质干细胞分化为神经元样细胞。用免疫组织化学SABC法鉴定神经丝蛋白(NF—M)、神经元特异性烯醇化酶(NSE)、巢蛋白(nestin)、微管联合蛋白-2(MAP-2)、生长相关蛋白-43(GAP-43)、胶质纤维酸性蛋白(GFAP)的表达。结果第5代间质干细胞形态达到均一，呈梭形。用川芎嗪诱导15min到3h，间质干细胞胞体逐渐增大，并伸出细长突起形似神经元样细胞。免疫组织化学显示NF-M、NSE、nestin、MAP-2和GAP-43表达阳性，而GFAP阴性。对照组上述染色均为阴性。结论川芎嗪可诱导骨髓间质干细胞分化为神经元样细胞。