Longitudinal in vivo effects of growth hormone overexpression on bone in transgenic mice.

In this study we examined the effect of systemic overexpression of GH on bone in transgenic mice longitudinally in vivo over a period of 9 months. We observed substantially increased BMC in GH transgenic mice and a significant reduction in serum osteocalcin. GH effects on bone were strongly dependent on gender and developmental stage. INTRODUCTION: State-of-the-art bone marker and microimaging technology was applied in this longitudinal study to examine bone metabolism, BMC, bone density, and cortical bone structure over the life span of growth hormone (GH) transgenic (tg) mice. MATERIALS AND METHODS: Thirty-eight mice from four genetic groups (male, female, tg, and controls) were examined with DXA, and their femur and tibia were examined with peripheral QCT (pQCT). Osteocalcin (formation) and collagen cross-links (resorption) from serum and urine were also measured at postnatal weeks 3, 6, 9, 12, 18, 26, and 38. RESULTS: GH tg mice displayed a significant increase in body weight (up to 50%) and BMC (up to 90%), but serum osteocalcin was significantly reduced compared with controls. GH tg females (but not males) displayed increased trabecular density over controls up to week 12. In contrast, male (but not female) GH tg mice displayed a higher cortical cross-sectional area than controls. Cortical density was significantly lower in both male and female GH tg mice compared with control mice. CONCLUSIONS: The increase in BMC in GH tg mice is associated with reduced serum osteocalcin levels, indicating that bone turnover may be lower than in the control mice. On a structural level, bone responds to GH excess in a gender-specific manner, with alterations varying substantially between different developmental stages.     

Blood pressure reduction in pregnancy by sodium chloride.

Volume expansion in the presence of elevated aldosterone availabilityis a hallmark of normal pregnancy. Intravascular volume depletioncharacterizes severe pregnancy-associated disease conditionssuch as intra-uterine growth retardation, chronic hypertensionor pre-eclampsia [1]. Two hypotheses have been forwarded toexplain volume depletion in pregnancy: the first hypothesischarges inappropriate sensing of vascular ‘overfilling’,resulting in an increased transendothelial loss of fluid tothe extravascular compartment. In contrast, the second hypothesisfocuses on vascular ‘underfilling’ due to inappropriatelylow aldosterone levels. The second hypothesis is based on theassumption that a compensatory increase in the circulating fluidvolume is required in normal pregnancy to support fetal substratedelivery. According to the second concept, maternal blood pressureincreases due to counter-regulatory mechanisms when placentalblood supply is reduced [2]. In support of the ‘underfilling’hypothesis are observations that a     

A Bayesian approach to subvoxel tissue classification in NMR microscopic images of trabecular bone

NMR microscopy is currently being used as an investigational tool for the evaluation of micromorphometric parameters of trabecular bone as a possible means to assess its strength. Since, typically, the image voxel size is not significantly smaller than individual trabecular elements, partial volume blurring can be a major complication for accurate tissue classification. In this paper, a Bayesian segmentation technique is reported that achieves improved subvoxel tissue classification. Each voxel is subdivided either into eight subvoxels twice the original resolution, or up to four subvoxels along the transaxial direction and the subvoxels optimally classified as either bone or marrow. Based on a statistical model for partial volume blurring, the likelihood for the number of marrow subvoxels in each voxel can be computed on the basis of its measured signal. To resolve the ambiguity of the location of the marrow subvoxels, a Gibbs distribution is introduced to model the interaction between the subvoxels. Neighboring subvoxel pairs with the same tissue label are encouraged, and pairs with distinct labels are penalized. The segmentation is achieved by maximizing the a posteriori probability of the label image using the block ICM (iterative conditional mode) algorithm. The potential of the proposed technique is demonstrated in real and synthetic NMR microscopic images.     

Dopamine transporters, D2 receptors, and glucose metabolism in corticobasal degeneration.

Alterations in presynaptic and postsynaptic dopaminergic system and cerebral glucose metabolism in corticobasal degeneration (CBD) were assessed to evaluate the potential usefulness of different imaging methods for CBD. (123)I-FP-CIT/(123)I-beta-CIT SPECT and (123)I-IBZM SPECT as well as (18)F-FDG PET were performed in eight CBD patients. Decreased presynaptic dopamine transporter binding was found in all CBD patients while D2 receptor binding was reduced in only one patient. (18)F-FDG PET displayed a contralateral hypometabolism in cortical and subcortical areas in seven out of eight patients. Our results demonstrate that glucose metabolism and DAT are reduced, while D2 receptors may be frequently preserved in CBD.     

Anastomotic stenosis after Roux-en-Y gastric bypass: A rational approach to treatment.

BACKGROUND: Anastomotic stenosis, a common sequela to Roux-en-Y gastric bypass, has a reported incidence of 1.6-27% and recurs in 17-33%. No universal guidelines for optimal treatment exist. The aim of this study was to develop guidelines to treat stenosis that achieve the lowest rate of recurrence while avoiding the complications of excessive dilation. METHODS: This prospective 2-part study enlisted consecutive patients undergoing Roux-en-Y gastric bypass who developed an anastomotic stenosis. In the first part, all patients, regardless of the grade of stenosis, underwent dilation to 12 mm and were followed up for recurrence. In the second part, patients underwent dilation according to the grade of stenosis (12 mm for low, 13.5 mm for medium, 15 mm for high) and were followed up for recurrence. RESULTS: Among 1345 consecutive Roux-en-Y gastric bypass patients, 204 developed an anastomotic stenosis (15.2%). No differences were found in gender, mean age, preoperative body mass index, or weight loss at 1 year. In part 1, the recurrence rate for low-, medium-, and high-grade stenosis was 2.6%, 34.4%, and 35.9%. In part 2, the corresponding rates were 9.7%, 26.3%, and 43.6%. The corresponding mean number of additional dilations per patient with recurrence in part 1 was 1.0, 1.5, and 2.1 and, in part 2, were 1.0, 1.0 and 1.2. CONCLUSION: The results of this study have shown that the stenosis grade can predict the risk of recurrence and determine the optimal balloon size. Definitive treatment was achieved in >90% of patients with low-grade stenosis dilated to 12 mm. Medium- and high-grade stenosis predicted > or =25% recurrence, but increasing the balloon size reduced the number of additional dilations required for patients with recurrence.     

Facilitating written work using computer word processing and word prediction.

OBJECTIVE: The purpose of this study was to investigate whether occupational therapy intervention that focused on teaching children to use word processing, either alone or with word prediction, was effective in improving the written communication skills of children with learning disabilities and handwriting problems. METHOD: A single-subject alternating treatments design was replicated across three children in grades 4 and 5. During the baseline phase the children wrote stories by hand; during the intervention phase, the children wrote stories, alternating among handwriting, word processing, and word processing with word prediction. Dependent variables focused on percentages of legible words, percentages of correctly spelled words, total amount written, and rate of writing. Data were analyzed by visual inspection. RESULTS: Results were variable. Two children had clear improvements in legibility when using either word processing alone or with word prediction. These same children demonstrated clear improvements in spelling when using word prediction. Though rate of writing was best for two children when using handwriting, relative to total amount produced, one method was not clearly preferable to another. CONCLUSION: Occupational therapy intervention involving word processing with word prediction improves the legibility and spelling of written assignments completed by some children with learning disabilities and handwriting difficulties. It is important to evaluate each child individually and provide training and ongoing support for technology use.     

Brain scintigraphy (SPECT) with thallium-201 in primary brain tumors]

We evaluated the role of thallium-201 single-photon emission-computed tomography (SPECT) in diagnosis, differential diagnosis and follow-up of 33 patients with primary brain tumors. 27 of 33 lesions were detectable by Tl-201 SPECT because only two of eight low-grade (grade 1 and 2) astrocytomas showed Tl-201 accumulation up to a tumor to nontumor ratio of 2.6. High grade (grade 3 and 4) astrocytomas showed Tl-201 accumulation in the range of 2.2 up to 13.0 and were different from low-grade astrocytomas. Noninvasive grading of astrocytomas is therefore possible, whereas differential diagnosis of oligodendrogliomas and astrocytomas or meningiomas was not possible with Tl-201. In the follow-up of six patients, we could demonstrate, that tumor progression is correlated with increasing and tumor regression with decreasing Tl-201 accumulations. This functional changing proceed morphological findings in CT. But vanishing of Tl-201 accumulation during therapy does not mean vanishing of tumor as could be demonstrated by follow-up.     

FASCIOCUTANEOUS ISLAND FLAPS FOR ORTHOPAEDIC MANAGEMENT IN LOWER LIMB RECONSTRUCTION USING DERMATOMAL PRECINCTS

This paper describes a technique of fasciocutaneous island flaps used in reconstruction of the lower limb. It is very versatile and some 26 individual flaps in 22 patients have been used to reconstruct skeletal and soft tissue problems from the popliteal fossa to the ankle joint. These longitudinally designed flaps made up of a trilaminate of skin, subcutaneous fat and fascia are aligned within the dermatomal precincts. The most important location for such flap design is along the peroneal compartment sitting within the L5 dermatome and incorporating the superficial peroneal nerve. It can be lengthened as far as the lateral malleolus and is an excellent reconstructive method to close defects over the lower third of the tibia. The medial compartment of the leg employing the saphenous nerve (L4 dermatome) is another area for fasciocutaneous island flap reconstruction, but use is restricted to the upper two-thirds of the tibial area. Posteriorly the island flap design sits along the S2 dermatome, this time incorporating the sural nerve to reconstruct defects of the calf and can be extended to include problems of the popliteal fossa. In the overall flap technique, the age of the patient is not a contraindication and cases with peripheral vascular disease have been treated successfully. The flaps may extend up to a 5:1 ratio in dimension. The operating time can be considerably shortened.