Body composition in the elderly: Total body water and anthropometry

Body composition measured with isotopic dilution was compared with anthropometric measurements. The study was carried out in 47 subjects from both sexes, 65 to 92 years old. Total body water (TBW), anthropometric measurements, and dynamometry were assessed. TBW was significatively higher in men than women and decreased with age. Dynamometry and fatfree mass were well correlated (r=0.73 in males and r=0.58 in females) and significantly different between sexes. A negative correlation was found for dynamometry with age, being significant for women. Linear regression equations to predict TBW from anthropometric measurements in males and females were obtained: Males: TBW(I)=19.349+0.617 weight(kg) — 0.931 mid-arm circumference(cm)+0.122 dynamometry (kg) Females: TBW(l)=−5.531+0.343 weight(kg)-0.213 triceps skinfold (mm)+ 0.148 dynamometry(kg) + 3.424 wrist diameter (cm). This simple model is proposed for use in epidemiological and field studies where other more sophisticated methods can not be applied.     

Human ORFeome Version 1.1: A Platform for Reverse Proteomics

The advent of systems biology necessitates the cloning of nearly entire sets of protein-encoding open reading frames (ORFs), or ORFeomes, to allow functional studies of the corresponding proteomes. Here, we describe the generation of a first version of the human ORFeome using a newly improved Gateway recombinational cloning approach. Using the Mammalian Gene Collection (MGC) resource as a starting point, we report the successful cloning of 8076 human ORFs, representing at least 7263 human genes, as mini-pools of PCR-amplified products. These were assembled into the human ORFeome version 1.1 (hORFeome v1.1) collection. After assessing the overall quality of this version, we describe the use of hORFeome v1.1 for heterologous protein expression in two different expression systems at proteome scale. The hORFeome v1.1 represents a central resource for the cloning of large sets of human ORFs in various settings for functional proteomics of many types, and will serve as the foundation for subsequent improved versions of the human ORFeome.     

Normal T cell subsets and lymphocyte activity in multiple sclerosis.

Nine patients with either chronic progressive or relapsing/remitting multiple sclerosis were treated with several courses of lymphopheresis. The lymphocytes obtained by this procedure showed a significantly lower percentage of OKT3+ cells than normal controls at the beginning of therapy. This percentage increased to normal levels after five lymphopheresis treatments and then decreased during the last stages of treatment. Patients had normal levels of OKT4+ and OKT8+ cells compared to controls and these percentages showed no statistically significant changes during the course of treatment. The proliferative response of patient's lymphocytes after stimulation with concanavalin A, PHA and alloantigen was not significantly different from normal controls and these responses were unchanged during the lymphopheresis treatment. Natural killer cell activity was also normal in our patients. The results reported in this study do not suggest a basic T cell abnormality in our patients with multiple sclerosis. Furthermore, the lymphopheresis treatments did not induce any significant change in T cell numbers or functional activity in vitro.     

Simple nephrectomy: transperitoneal approach

Transperitoneal laparoscopic nephrectomy is performed much as originally described by Clayman and associates, although preoperative embolization of the kidney is no longer routine. Some surgeons use a hand-assisted technique, especially in difficult cases or when the organ is being removed intact, as in live-donor nephrectomy.     

Grandparenting and psychosocial health among older Chileans: A longitudinal analysis

Objectives: To investigate factors associated with Chilean grandparents’ provision of help to grandchildren and associations between provision of such help and grandparents’ mental well-being two years later. Methods: Data are drawn from a representative sample of 2000 people aged 66–68 resident in low- or middle-income areas of Santiago who were surveyed in 2005 and re-interviewed two years later. Multivariable analyses were used to investigate factors associated with provision of help to grandchildren at baseline and associations between providing such help and life satisfaction, SF36-Mental Component Summary scores, and depression two years later. Results: 41% of grandparents lived with one or more grandchildren and over half provided four or more hours per week of help to grandchildren. Models controlling for baseline mental health, grandchild characteristics, marital and household characteristics, socio-economic status and functional health showed that grandfathers who provided four or more hours per week of help to grandchildren had better life satisfaction two years later and that those providing material help had higher SF36 MCS scores at follow-up. Grandmothers providing four or more hours of help a week had lower risks of depression. Conclusion: Older Chileans make important contributions to their families through the provision of help to grandchildren and these appear to have some benefits for their own psychosocial health. Gender differences in the pattern of associations may reflect differences in overall family responsibilities and merit further investigation.     

Electrophysiology and ultrastructure of canine subendocardial Purkinje cells isolated from control and 24-hour infarcted hearts

Ventricular arrhythmias that accompany myocardial infarction in dogs may be secondary to the altered electrophysiological properties of the subendocardial Purkinje fibers that survive 24 hours after the coronary occlusion. To better understand the ionic mechanisms that underlie the altered electrical activity of these fibers, we have dispersed, using an enzymatic technique, Purkinje cells from the subendocardium of the infarcted ventricle (IZPCs) and compared their electrical and structural properties to Purkinje cells dispersed from fiber strands (SPCs) and from the subendocardium of the noninfarcted ventricle (NZPCs). Ultrastructural analysis of these cells shows that IZPCs contain an increased number of lipid droplets when compared with the SPCs and NZPCs. In addition, transmembrane action potentials of IZPCs have reduced resting potentials, action potential amplitudes, and upstroke velocity and are increased in duration when compared with either SPCs or NZPCs. Input resistance of IZPCs is increased over that measured in control cells (SPCs and NZPCs). Furthermore, the time course of the process of electrical restitution of action potential duration is altered in IZPCs with long action potentials. Finally, using K+-sensitive microelectrode techniques, we have determined that intracellular free K+ activity (aKi) in IZPCs (93.7 +/- 15 mM) is not significantly different from control aKi measurements (SPC, 106 +/- 13 mM; NZPC, 103 +/- 12 mM). Thus a reduction in aKi does not provide a basis for the reduced resting potentials observed in IZPCs. By studying the relation between the resting potential and log [K+]o we determined that in IZPCs with reduced resting potentials, there is a significant increase in the PNa/PK ratio when compared with control. In summary, to better understand the cellular basis of ventricular arrhythmias postinfarction, we have developed a single cell model that will allow for more rigorous electrophysiological studies of the specific ionic currents that underlie the abnormal electrophysiology.     

Electromagnetic organ tracking allows for real-time compensation of tissue shift in image-guided laparoscopic rectal surgery: results of a phantom study

Background

Laparoscopic resection is a minimally invasive treatment option for rectal cancer but requires highly experienced surgeons. Computer-aided technologies could help to improve safety and efficiency by visualizing risk structures during the procedure. The prerequisite for such an image guidance system is reliable intraoperative information on iatrogenic tissue shift. This could be achieved by intraoperative imaging, which is rarely available. Thus, the aim of the present study was to develop and validate a method for real-time deformation compensation using preoperative imaging and intraoperative electromagnetic tracking (EMT) of the rectum.

Methods

Three models were compared and evaluated for the compensation of tissue deformation. For model A, no compensation was performed. Model B moved the corresponding points rigidly to the motion of the EMT sensor. Model C used five nested linear regressions with increasing level of complexity to compute the deformation (C1–C5). For evaluation, 14 targets and an EMT organ sensor were fit into a silicone-molded rectum of the OpenHELP phantom. Following a computed tomography, the image guidance was initiated and the rectum was deformed in the same way as during surgery in a total of 14 experimental runs. The target registration error (TRE) was measured for all targets in different positions of the rectum.

Results

The mean TRE without correction (model A) was 32.8 ± 20.8 mm, with only 19.6 % of the measurements below 10 mm (80.4 % above 10 mm). With correction, the mean TRE could be reduced using the rigid correction (model B) to 6.8 ± 4.8 mm with 78.7 % of the measurements being <10 mm. Using the most complex linear regression correction (model C5), the error could be reduced to 2.9 ± 1.4 mm with 99.8 % being below 10 mm.

Conclusion

In laparoscopic rectal surgery, the combination of electromagnetic organ tracking and preoperative imaging is a promising approach to compensating for intraoperative tissue shift in real-time.