Impact of gender on coronary bypass operative mortality

I examine trends in single mothers' living arrangements using data from the 1970-1995 Current Population Surveys. I create a consistent trend by correcting a coding problem that stemmed from the misidentification of children living in multigenerational households before 1984. Revised estimates show that the number of single mothers in each of these years was undercounted by 200,000-300,000. All of these women were subfamily heads living with their parents, and the problem occurred disproportionately among teens and black women. The uncorrected trend falsely indicates a large increase in the share of single mothers living with their parents. In reality, there was little change in the percentage of single mothers living in this arrangement over the time period. However, the data indicate a large increase in the rate of cohabitation and a comparable decline in the rate of living independently among this population.     

Parallel implementations of individual-based models in biology: bulletin- and non-bulletin-board approaches

Low-field magnetic resonance imaging (MRI) was performed on the stifle joints of four normal adult mongrel dogs using a 0.064 Tesla scanner. Markers were placed on each stifle joint to serve as reference points for comparing gross sections with the images. A T1-weighted sequence was used to image one stifle joint on each dog in the sagittal plane and the other stifle joint in the dorsal plane. The dogs were euthanized immediately following MRI and the stifle joints frozen intact. Each stifle joint was then embedded in paraffin, again frozen, and sectioned using the markers as reference points. On T1-weighted images, synovial fluid had low signal intensity (dark) compared to the infrapatellar fat pad which had a high signal intensity (bright). Articular cartilage was visualized as an intermediate bright signal and was separated from trabecular bone by a dark line representing subchondral bone. Menisci, fibrous joint capsule, and ligamentous structures appeared dark. In the true sagittal plane, the entire caudal cruciate ligament was often seen within one image slice. The patella was visualized as an intermediate bright signal (trabecular bone) surrounded by a low intensity signal (cortical bone). The trochlea and the intercondylar notch were difficult areas to analyze due to signal volume averaging of the curved surface of these areas and the presence of several types of tissues.     

Bioactivation of the proximal food mutagen 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP) to DNA-binding species by human mammary gland enzymes

We have investigated phase II activation of the food-derived mutagen 2-hydroxyamino-1-methyl-6-phenyl[4,5-b]pyridine (N-OH-PhIP) by cytosolic acetyltransferase, sulfotransferase, and tRNA synthetase/kinase enzymes from human breast tissue. Cytosol from homogenates of mammary gland tissue obtained from breast-reduction surgery or mastectomy was incubated with and without enzyme-specific cofactors, and mutagen binding of calf thymus DNA was quantified by 32P-postlabeling. In addition, microsomal fractions of mammary epithelial cells from some individuals were examined for prostaglandin H synthetase activation of N-OH-PhIP. Our results show that all four enzymes can participate in activating N-OH-PhIP, thus inducing PhIP-DNA adduct formation in human mammary cells. However, not all individuals exhibited all these activities; instead each individual showed a combination of one or more activation pathways. The present findings demonstrate that the human mammary gland has the capacity to metabolically activate a dietary mutagen by several enzyme systems, including acetyltransferase, sulfotransferase, tRNA synthetase/kinase, and prostaglandin hydroperoxidase catalysis.     

Surgical myocardial revascularization

In conclusion, surgical myocardial revascularization has utilized diverse methods to increase blood flow to the starving myocardium. These methods initially used the microcirculation as the portal to reach myocytes until angiography showed that the obstructions were macrovascular. This resulted in a 30-year era of direct attack on the coronary blockages by coronary bypass. Surgical conduits unfortunately have longevity considerably less than that of native arteries and are limited in number. Alternative conduits, both biologic and prosthetic, have not yet proved to have the same clinical results as the ITA. More patients are living long enough to have the extensiveness of their disease exhaust conventional therapies. Newer therapy, restricted thus far to untreatables, revisits the microcirculation by making laser channels. These many innovative procedures have benefited hundreds of thousands of patients. They emerged from the probity and innovation of many individual surgeons.     

Expression of RNA from developmentally important genes in preimplantation bovine embryos produced in TCM supplemented with BSA

Rats given unilateral medial agranular (AGm) cortex ablations show neglect for contralateral multimodal stimuli, symptoms that are reversed by 48 hr of light deprivation. To address processes that contribute to this restorative effect, both the rats' locomotion and basal ganglia c-fos expression were studied. AGm-lesioned rats showed less activity in continuous darkness than in normal (12 hr light/12 hr dark) cycles, and the reduced locomotion correlated with the extent of their subsequent behavioral recovery. The AGm ablation reduced the numbers of amphetamine-stimulated Fos-immunoreactive nuclei in the ipsilateral dorsolateral striatum, where the AGm innervation is normally densest. Light deprivation also reduced Fos in this striatal region and attenuated the lesion-induced hemispheric Fos asymmetry. A restored balance of activity between the 2 hemispheres, especially the basal ganglia, appears central to the action of light deprivation.     

Ultrasonographic detection of adrenal gland tumors in two ferrets

Hyperadrenocorticism is recognized as a common medical condition in middle- to old-aged ferrets. Because diagnosis of adrenocortical tumors in ferrets, using results of adrenocorticotropic hormone stimulation or dexamethasone suppression tests, is unreliable, ultrasonography was used as an alternative to laparotomy for the detection of tumors in 2 ferrets. The diagnosis was confirmed by surgical excision and histologic examination of the adrenal gland. In a typical manifestation of the condition, clinical signs in 1 ferret included vulvar swelling and serous to mucopurulent vaginal discharge, which resolved after the adrenalectomy.     

Absolute conservation of residue 6 of immunoglobulin heavy chain variable regions of class IIA is required for correct folding

While studying the expression of single-chain antibodies (scFv) derived from several murine monoclonal antibodies, we found that residue 6 in Framework region 1 of the heavy chain variable domain plays a crucial role in antibody folding. Binding activity of three murine antibodies with a heavy chain variable region (VH) subgroup IIA was completely lost when at this position the wild-type residue glutamine (Q) was substituted by glutamate (E). Increased sensitivity towards trypsin digestion of soluble scFv suggested that the lack of binding activity was caused by incorrect folding of Q6E mutants. Grafting of the three additional class IA derived FR1 residues, based upon the comparison between both classes of VH sequences, on to the 'defect' subgroup IIA sequence, partially restored the antigen binding activity of the Q6E-containing scFv. Our results suggest that residue 6 of the heavy chain may be part of a folding nucleus, involving the first two beta-strands of Framework region 1. The evolutionary conservation of either glutamine or glutamate at position 6 in different antibody families may well indicate that within immunoglobulin VH domains, different family specific folding nuclei have evolved.