Macrosocial determinants of population health in the context of globalization

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55738/1/florey_globalization_2007.pd

Towards an atlas of mammalian cell ultrastructure by cryo soft X ray tomography

We provide a catalog of 3D cryo soft X-ray tomography (cryo-SXT) images obtained from ~6–12 µm thick mouse adenocarcinoma cells. Included are multiple representative images of nuclei, nucleoli, nuclear membrane, nuclear membrane channels, mitochondria, lysosomes, endoplasmic reticulum, filaments and plasma membrane, plus three structures not previously described by cryo-SXT, namely Golgi, microvilli and nuclear-membrane blebs. Sections from the 3D cryo-SXT tomograms for all the preceding structures closely resemble those seen by thin-section transmission electron microscopy (TEM). Some structures such as nuclear-membrane channels and nuclear-membrane blebs are more easily detected by cryo-SXT than TEM most likely due to their better contrast and cellular preservation in cryo-SXT combined with the ability to rapidly locate these structures within a full 3D image. We identify and discuss two current limitations in cryo-SXT: variability in image quality and difficulties in detecting weaker contrast structures such as chromatin and various nuclear bodies. Progress on these points is likely to come from the solution of several technical problems in image acquisition, plus the implementation of advanced cryo soft X-ray microscopy approaches such as phase contrast or optical sectioning

The 3.7 Å projection map of the glycerol facilitator GlpF: a variant of the aquaporin tetramer

GlpF, the glycerol facilitator protein of Escherichia coli, is an archetypal member of the aquaporin superfamily. To assess its structure, recombinant histidine-tagged protein was overexpressed, solubilized in octylglucoside and purified to homogeneity. Negative stain electron microscopy of solubilized GlpF protein revealed a tetrameric structure of ∼80 Å side length. Scanning transmission electron microscopy yielded a mass of 170 kDa, corroborating the tetrameric nature of GlpF. Reconstitution of GlpF in the presence of lipids produced highly ordered two-dimensional crystals, which diffracted electrons to 3.6 Å resolution. Cryoelectron microscopy provided a 3.7 Å projection map exhibiting a unit cell comprised of two tetramers. In projection, GlpF is similar to AQP1, the erythrocyte water channel. However, the major density minimum within each monomer is distinctly larger in GlpF than in AQP1

Surgery for 'asymptomatic' mild primary hyperparathyroidism improves some clinical symptoms postoperatively

OBJECTIVE AND BACKGROUND: Most primary hyperparathyroidism (pHPT) patients do not conform to the guidelines for parathyroidectomy established by an international panel of specialists and have a mild pHPT. This group is typically defined as \u27asymptomatic\u27. The primary aim of this study was to determine symptom improvement in this \u27asymptomatic\u27 group after parathyroidectomy. Secondly, we aimed to create a preoperative clinical score predicting postoperative symptom resolution. DESIGN: A prospective nonrandomized study included patients with mild pHPT. METHODS: A questionnaire (22 items) was given to \u27asymptomatic\u27 patients preoperatively and at 3, 6, and 12 postoperative months. A logistic regression was performed to create a preoperative clinical score. RESULTS: One hundred and sixteen patients were included. Postoperatively, HPT was resolved in 98% of patients. Twelve of 22 nonspecific symptoms were improved at 1 year. Subgroups analysis showed a greater improvement in patients <70 years and those with a serum calcium level ≥2.6 mmol/l preoperatively. A clinical score, based on age and five symptoms, was established to predict the clinical improvement after surgery in mild pHPT patients with a positive predictive value of 81%. CONCLUSION: Patients with asymptomatic pHPT have clinical improvement of their symptoms postoperatively even after 1 year. Younger patients and those with higher preoperative calcium levels show the best improvement