Bioavailability Studies of Acetaminophen and Nitrofurantoin

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97190/1/j.1552-4604.1974.tb02312.x.pd

Linear pharmacokinetic equations allowing direct calculation of many needed pharmacokinetic parameters from the coefficients and exponents of polyexponential equations which have been fitted to the data

It is shown that if the numerical values of the coefficients and exponents of the polyexponential equation describing the whole blood (plasma or serum) concentration after administration of a drug by bolus intravenous injection, or during or after termination of a constantrate intravenous infusion, are known, then many needed pharmacokinetic parameters may be obtained directly. Parameters readily calculated by simple arithmetic are as follows: plasma or serum clearance, Cl p ; volume of plasma compartment, V p ; volume of distribution at steady state, V dss ; V{darea} or V β , extrapolated volume of distribution, V dexr ; half-life of elimination, t 1/2 ; amount metabolized and/or excreted to time t, (A e ); amount in the body at time t, A b ; amount in the plasma (reference) compartment at time t, A p ; and amount in other compartments at time t, A o . Simulations have shown that the equations yield the correct answers for an n-compartment mammillary model with central compartment elimination only, when rate constants, dose, and a value of V p have been assigned. Since whole blood (plasma or serum) concentrationtime data always lead to ambiguities as to which specific model is involved, the equations are most appropriate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45069/1/10928_2005_Article_BF01062831.pd

C-Terminal Extension of the Yeast Mitochondrial DNA Polymerase Determines the Balance between Synthesis and Degradation

Saccharomyces cerevisiae mitochondrial DNA polymerase (Mip1) contains a C-terminal extension (CTE) of 279 amino acid residues. The CTE is required for mitochondrial DNA maintenance in yeast but is absent in higher eukaryotes. Here we use recombinant Mip1 C-terminal deletion mutants to investigate functional importance of the CTE. We show that partial removal of the CTE in Mip1Δ216 results in strong preference for exonucleolytic degradation rather than DNA polymerization. This disbalance in exonuclease and polymerase activities is prominent at suboptimal dNTP concentrations and in the absence of correctly pairing nucleotide. Mip1Δ216 also displays reduced ability to synthesize DNA through double-stranded regions. Full removal of the CTE in Mip1Δ279 results in complete loss of Mip1 polymerase activity, however the mutant retains its exonuclease activity. These results allow us to propose that CTE functions as a part of Mip1 polymerase domain that stabilizes the substrate primer end at the polymerase active site, and is therefore required for efficient mitochondrial DNA replication in vivo

Obesity surgery makes patients healthier and more functional - real world results from the United Kingdom National Bariatric Surgery Registry

Background The National Bariatric Surgery Registry (NBSR) is the largest bespoke database in the field in the United Kingdom. Objectives Our aim was to analyze the NBSR to determine whether the effects of obesity surgery on associated co-morbidities observed in small randomized controlled clinical trials could be replicated in a "real life" setting within U.K. healthcare. Setting United Kingdom. Methods All NBSR entries for operations between 2000 and 2015 with associated demographic and co-morbidity data were analyzed retrospectively. Results A total of 50,782 entries were analyzed. The patients were predominantly female (78%) and white European with a mean age of 45 ± 11 years and a mean body mass index of 48 ± 8 kg/m2. Over 5 years of follow-up, statistically significant reductions in the prevalence of type 2 diabetes, hypertension, dyslipidemia, sleep apnea, asthma, functional impairment, arthritis, and gastroesophageal reflux disease were observed. The "remission" of these co-morbidities was evident 1 year postoperatively and reached a plateau 2 to 5 years after surgery. Obesity surgery was particularly effective on functional impairment and diabetes, almost doubling the proportion of patients able to climb 3 flights of stairs and halving the proportion of patients with diabetes related hyperglycemia compared with preoperatively. Surgery was safe with a morbidity of 3.1% and in-hospital mortality of .07% and a reduced median inpatient stay of 2 days, despite an increasingly sick patient population. Conclusions Obesity surgery in the U.K. results not only in weight loss, but also in substantial improvements in obesity-related co-morbidities. Appropriate support and funding will help improve the quality of the NBSR data set even further, thus enabling its use to inform healthcare policy

Aluminum toxicity in childhood

Aluminum intoxication is an iatrogenic disease caused by the use of aluminum compounds for phosphate binding and by the contamination of parenteral fluids. Although organ aluminum deposition was noted as early as 1880 and toxicity was documented in the 1960s, the inability to accurately measure serum and tissue aluminum prevented delineation of its toxic effects until the 1970s. Aluminum toxicity has now been conclusively shown to cause encephalopathy, metabolic bone disease, and microcytic anemia.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47831/1/467_2004_Article_BF00869743.pd

Gene expression profile of cervical and skin tissues from human papillomavirus type 16 E6 transgenic mice

<p>Abstract</p> <p>Background</p> <p>Although K14E6 transgenic mice develop spontaneous tumors of the skin epithelium, no spontaneous reproductive tract malignancies arise, unless the transgenic mice were treated chronically with 17β-estradiol. These findings suggest that E6 performs critical functions in normal adult cervix and skin, highlighting the need to define E6-controlled transcriptional programs in these tissues.</p> <p>Methods</p> <p>We evaluated the expression profile of 14,000 genes in skin or cervix from young K14E6 transgenic mice compared with nontransgenic. To identify differentially expressed genes a linear model was implemented using R and the LIMMA package. Two criteria were used to select the set of relevant genes. First a set of genes with a Log-odds ≥ 3 were selected. Then, a hierarchical search of genes was based on Log Fold Changes.</p> <p>Results</p> <p>Microarray analysis identified a total of 676 and 1154 genes that were significantly up and down-regulated, respectively, in skin from K14E6 transgenic mice. On the other hand, in the cervix from K14E6 transgenic mice we found that only 97 and 252 genes were significantly up and down-regulated, respectively. One of the most affected processes in the skin from K14E6 transgenic mice was the cell cycle. We also found that skin from transgenic mice showed down-regulation of pro-apoptotic genes and genes related to the immune response. In the cervix of K14E6 transgenic mice, we could not find affected any gene related to the cell cycle and apoptosis pathways but did observe alterations in the expression of immune response genes. Pathways such as angiogenesis, cell junction and epidermis development, also were altered in their gene expression profiles in both tissues.</p> <p>Conclusion</p> <p>Expression of the HPV16 E6 oncoprotein in our model alters expression of genes that fell into several functional groups providing insights into pathways by which E6 deregulate cell cycle progression, apoptosis, the host resistance to infection and immune function, providing new opportunities for early diagnostic markers and therapeutic drug targets.</p

Genetic Rearrangements Can Modify Chromatin Features at Epialleles

Analogous to genetically distinct alleles, epialleles represent heritable states of different gene expression from sequence-identical genes. Alleles and epialleles both contribute to phenotypic heterogeneity. While alleles originate from mutation and recombination, the source of epialleles is less well understood. We analyze active and inactive epialleles that were found at a transgenic insert with a selectable marker gene in Arabidopsis. Both converse expression states are stably transmitted to progeny. The silent epiallele was previously shown to change its state upon loss-of-function of trans-acting regulators and drug treatments. We analyzed the composition of the epialleles, their chromatin features, their nuclear localization, transcripts, and homologous small RNA. After mutagenesis by T-DNA transformation of plants carrying the silent epiallele, we found new active alleles. These switches were associated with different, larger or smaller, and non-overlapping deletions or rearrangements in the 3′ regions of the epiallele. These cis-mutations caused different degrees of gene expression stability depending on the nature of the sequence alteration, the consequences for transcription and transcripts, and the resulting chromatin organization upstream. This illustrates a tight dependence of epigenetic regulation on local structures and indicates that sequence alterations can cause epigenetic changes at some distance in regions not directly affected by the mutation. Similar effects may also be involved in gene expression and chromatin changes in the vicinity of transposon insertions or excisions, recombination events, or DNA repair processes and could contribute to the origin of new epialleles

Novel method of estimating volume of distribution of a drug obeying Michaelis-Menten elimination kinetics

The novel method of estimating the volume of distribution involves (a) administering an appropriate bolus intravenous dose of the drug, (b) starting a constant-rate intravenous infusion of the drug at the same time, (c) maintaining the infusion for a given number of hours, (a) measuring the drug concentration over the entire time course, (e) computer-fitting the post-infusion data to obtain estimates of V m and K m , (f) estimating the total area under the concentration-time curve from zero time to infinity, and (g) iteratively solving a cubic equation to obtain the estimate of the volume of distribution. The method was applied to ethanol in the cat and yielded an average value of 635ml/kg (63.5% of body weight) with a coefficient of variation of 23.0%. This is equivalent to total body water in the cat.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45074/1/10928_2005_Article_BF01312262.pd

Genome-Wide Data-Mining of Candidate Human Splice Translational Efficiency Polymorphisms (STEPs) and an Online Database

Variation in pre-mRNA splicing is common and in some cases caused by genetic variants in intronic splicing motifs. Recent studies into the insulin gene (INS) discovered a polymorphism in a 5' non-coding intron that influences the likelihood of intron retention in the final mRNA, extending the 5' untranslated region and maintaining protein quality. Retention was also associated with increased insulin levels, suggesting that such variants--splice translational efficiency polymorphisms (STEPs)--may relate to disease phenotypes through differential protein expression. We set out to explore the prevalence of STEPs in the human genome and validate this new category of protein quantitative trait loci (pQTL) using publicly available data.Gene transcript and variant data were collected and mined for candidate STEPs in motif regions. Sequences from transcripts containing potential STEPs were analysed for evidence of splice site recognition and an effect in expressed sequence tags (ESTs). 16 publicly released genome-wide association data sets of common diseases were searched for association to candidate polymorphisms with HapMap frequency data. Our study found 3324 candidate STEPs lying in motif sequences of 5' non-coding introns and further mining revealed 170 with transcript evidence of intron retention. 21 potential STEPs had EST evidence of intron retention or exon extension, as well as population frequency data for comparison.Results suggest that the insulin STEP was not a unique example and that many STEPs may occur genome-wide with potentially causal effects in complex disease. An online database of STEPs is freely accessible at http://dbstep.genes.org.uk/