Predicting the birth characteristics of normal fetuses 14 weeks before delivery

This investigation has evaluated the ability of Rossavik growth models (derived from data obtained before 26 weeks) to predict birth characteristics in normal fetuses (assuming no growth after 38 weeks). Both weight and head circumference were predicted without systematic errors and the ranges of the random errors were approximately +/- 10% and +/- 5%, respectively. A range of approximately +/- 10% for the random error was also found for the abdominal and thigh circumferences, but both parameters were systematically overestimated (17.3% and 6.4%, respectively). No evidence of a relationship between the percent deviation and age at delivery (up to 41 weeks) was found for any of the parameters studied. As indicators of pregnancy outcome, Growth Potential Realization Index (GPRI) values were calculated for each parameter (predicted values corrected for systematic errors were used for the abdominal and thigh circumferences). Mean GPRI values were not significantly different from 100% and the ranges were approximately 90% to 110% except for the head circumference (range: 95% to 105%). These results indicate that GPRI values can be used to characterize the outcome of prenatal growth processes on an individual basis, with each fetus acting as its own control.     

Differential expression of mutant and normal beta T3 receptor alleles in kindreds with generalized resistance to thyroid hormone.

Thyroid hormone resistance (THR) is primarily an autosomal dominant inherited disease characterized by resistance of pituitary and peripheral tissues to the action of thyroid hormone. We investigated whether the heterogeneous phenotypic features that occur not only among kindreds but also within the same kindred might be due to the expression of differing ratios of mutant and normal receptors in tissues. Using an allele-specific primer extension method, we determined the relative expression of normal and mutant mRNAs from the fibroblasts of affected and unaffected members of two kindreds with TRH: A-H and N-N. While two affected members of A-H, as expected, had nearly equal amounts of normal and mutant hTR beta mRNA, two other members had mutant mRNA levels that accounted for at least 70% of the hTR beta mRNA. Phenotypic variability within and between kindreds with generalized resistance to thyroid hormone GRTH may be due to this differential expression of the mutant and wild type mRNA. Furthermore, when several clinical parameters of THR were compared in several affected members from two kindreds with GRTH, we found that two cases in one kindred exhibited a high mutant-to-normal hTR beta ratio and had considerably more bone resistance during their development. In certain kindreds with THR, differing ratios of normal and mutant hTR receptors may be age and growth related and may account for the reported attenuation of phenotypic symptoms with age.     

Management of Patients With Aortocoronary Saphenous Vein Graft Aneurysms: JACC State-of-the-Art Review

Saphenous vein graft aneurysms (SVGAs) following coronary artery bypass grafting (CABG) surgery were first described in 1975. Although rare, in the absence of a prompt diagnosis, SVGAs can be responsible for serious complications and adverse outcomes. The clinical presentation of SVGAs described in the literature can vary from an asymptomatic patient with an incidental radiological finding to a profoundly shocked patient with life-threatening hemorrhage secondary to SVGA rupture. Improvements in diagnostic tools within the last decade, such as multislice computed tomographic scanning, has enabled early detection of SVGAs, and therefore, an expansion of the current management options. In this review, the current data and knowledge about clinical presentation, diagnosis, natural history, and treatment of SVGAs are updated, with a specific emphasis on the evolution of management strategies of this rare complication over the last 45 years. Finally, a clinical algorithm to guide decision-making and management is proposed.     

Durable,acid-resistant copolymers from industrial by-product sulfur and microbially-produced tyrosine

The search for alternative feedstocks to replace petrochemical polymers has centered on plant-derived monomer feedstocks. Alternatives to agricultural feedstock production should also be pursued, especially considering the ecological damage caused by modern agricultural practices. Herein, l-tyrosine produced on an industrial scale by E. coli was derivatized with olefins to give tetraallyltyrosine. Tetraallyltyrosine was subsequently copolymerized via its inverse vulcanization with industrial by-product elemental sulfur in two different comonomer ratios to afford highly-crosslinked network copolymers TTS_x (x = wt% sulfur in monomer feed). TTS_x copolymers were characterized by infrared spectroscopy, elemental analysis, thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis (DMA). DMA was employed to assess the viscoelastic properties of TTS_x through the temperature dependence of the storage modulus, loss modulus and energy damping ability. Stress–strain analysis revealed that the flexural strength of TTS_x copolymers (>6.8 MPa) is more than 3 MPa higher than flexural strengths for previously-tested inverse vulcanized biopolymer derivatives, and more than twice the flexural strength of some Portland cement compositions (which range from 3–5 MPa). Despite the high tyrosine content (50–70 wt%) in TTS_x, the materials show no water-induced swelling or water uptake after being submerged for 24 h. More impressively, TTS_x copolymers are highly resistant to oxidizing acid, with no deterioration of mechanical properties even after soaking in 0.5 M sulfuric acid for 24 h. The demonstration that these durable, chemically-resistant TTS_x copolymers can be prepared from industrial by-product and microbially-produced monomers via a 100% atom-economical inverse vulcanization process portends their potential utility as sustainable surrogates for less ecofriendly materials.

Copolymers of waste sulfur and bacterially-produced tyrosine are reported.     

Characteristics of Patients Who Avoid Wheat and/or Gluten in the Absence of Celiac Disease

Background

Gastrointestinal symptoms that respond to the removal of wheat and/or gluten are becoming more common. Patients who avoid wheat and/or gluten (PWAWG) are a heterogeneous group and predominantly self-diagnosed prior to presenting for clinical evaluation.

Specific aim

We characterized PWAWGs seen at a tertiary care referral center and compared them to patients with celiac disease (CD) and subjects in the National Health and Nutrition examination survey (NHANES).

Methods

This was a cross-sectional study evaluating patients seen by four gastroenterologists at a CD referral center. Baseline characteristics, laboratory values, and medical comorbidities were compared to CD patients who presented at the same center and subjects enrolled in NHANES.

Results

Eighty-four PWAWGs were identified and compared to 585 CD patients and 2,686 NHANES patients. Thirty-two alternative diagnoses were made in 25 (30 %) PWAWGs, including small intestinal bacterial overgrowth and fructose/lactose intolerance. When compared to patients with CD, PWAWGs had similar body mass index (BMI, 23.1 vs. 23.5, p = 0.54) and mean hemoglobin value (13.4 vs. 13.3, p = 0.6). When compared to male and female patients in NHANES, BMI, folate, and mean hemoglobin values were lower in PWAWGs. Both male and female PWAWGs had a lower prevalence of hypertension.

Conclusion

While there are similarities between CD and PWAWGs that could possibly be due to shared HLA haplotypes or an effect of the gluten-free diet, alternative diagnoses are common in these patients. PWAWGs have a similar cardiovascular profile as CD patients in terms of lower BMI and lower prevalence of hypertension.     

Distribution of hyaluronic acid and chondroitin sulfate proteoglycans in the presumptive aganglionic terminal bowel of ls/ls fetal mice: an ultrastructural analysis

The terminal colon of the ls/ls mouse is aganglionic because an intrinsic defect prevents its colonization by cells migrating from the neural crest. Previous studies showed that laminin, type IV collagen, and glycosaminoglycans accumulate in the region of the presumptive aganglionic ls/ls bowel through which crest-derived cells would be expected to migrate. It was suggested that crest-derived cells might fail to enter the abnormal bowel because they receive inappropriate signals from a defective extracellular matrix. This hypothesis was evaluated by analyzing the ultrastructure of the extracellular matrix in mutant and control gut. Tissue was fixed in the presence of ruthenium red before or after selective enzymatic digestion. Heparan sulfate proteoglycan (diameter approximately equal to 15 nm) and chondroitin sulfate proteoglycan (diameter approximately equal to 20-50 nm) granules were found in both control and presumptive aganglionic gut. The heparan sulfate proteoglycan granules were primarily located within formed basal laminae, while chondroitin sulfate proteoglycan granules decorated plasma membranes and 5 nm hyaluronic acid microfibrils that formed a network in the extracellular matrix. At day E11.5, the mutant gut differed from the control in the following: 1) Hyaluronic acid microfibrils were longer and more numerous. 2) There were larger numbers of chondroitin sulfate proteoglycan granules associated with cell membranes and with hyaluronic acid microfibrils. By day E13 the spaces between mesenchymal cells of the outer wall of the control bowel contained a regular lattice of hyaluronic acid microfibrils studded with chondroitin sulfate proteoglycan granules. Instead of this lattice, tangles of excessively long hyaluronic acid microfibrils, coated more heavily than in the control with chondroitin sulfate proteoglycan granules, were found in the presumptive aganglionic gut. These results confirm that the extracellular matrix is abnormal in the presumptive aganglionic bowel of the ls/ls mouse; moreover, they also indicate that the defect involves not one, but several components of the extracellular matrix, as well as their distribution. The defective extracellular matrix is apparent at a time when crest-derived cells would be expected to be migrating in the terminal bowel and is located in their path. The observations thus support the idea that a localized abnormality of the extracellular matrix interferes with the colonization of the terminal bowel by crest-derived cells in the ls/ls mouse.