Combined Drug Treatment of Obesity

Pharmacological treatment of obesity has been neglected as a viable therapeutic option for many years. Recent long term studies with combinations of obesity drugs gives promise that drugs may play a role in weight maintenance, which classically has been the most difficult aspect of treating obesity. Currently available obesity drugs include centrally acting adrenergic agents and serotonin agonists. Drugs still in development include a lipase inhibitor that produces fat malabsorption, a combined adrenergic-serotonergic reuptake inhibitor, various gut-central nervous system peptides, and a number of beta-3 agonists. Any of these obesity drugs given alone produces modest weight loss, and for most, weight loss continues for as long as medication is given. The most successful drug regimens to date are combinations of phentermine and fenfluramine or of ephedrine, caffeine, and/or aspirin. The former combination produces reduction in body weight and complications of obesity for 2 to almost 4 years in clinical trials to date. More research is needed to document long term efficacy and particularly the long term safety of these and other combinations.     

Self-Reported Substantial 1-Year Weight Change Among Men and Women in the United States

Population-based data have not been readily available on relatively short-term changes in weight. Therefore, we sought to determine the nature of self-reported substantial (> 10%) weight change over one year in a representative sample of the US population which participated in the 1989 National Health Interview Survey (NHIS). Across all ages, a larger proportion of women than men reported both weight loss as well as weight gain of any amount (18.9% vs. 16.1% for weight loss and 20.0% vs. 16.1% for weight gain). In sex-specific logistic regression analyses, significant risk factors common to both sexes for substantial weight loss included divorced/separated marital status, smoking, increased number of blood pressure checks, increased BMI (body mass index) and increased number of bed days. Black race reduced the risk of weight loss for both men and women. Sex-specific risk factors for weight loss in men only were widowhood or never married marital status, while increasing age was a protective factor in women only. Concerning weight gain > 10% over the past year, increased number of blood pressure checks and having one or more diabetic parents were significant risk factors among both men and women; while never being married, increased age, BMI, and education exerted a protective effect in both sexes. For women only, risk factors for weight gain included black race, increased number of contacts with a health professional, and being unemployed. Intention to lose weight was associated with both weight gain and weight loss in both sexes, although it did not serve as a confounder in any of these relationships. A greater likelihood of substantial weight loss among women relative to men was diminished for persons with higher BMI, higher number of blood pressure checks, being widowed, divorced or separated, and intention to lose weight. A greater likelihood of substantial weight gain among women relative to men was diminished for persons with low BMI. The results of this cross-sectional study of weight change, involving a one-year follow-up period, generally correspond with the results obtained by longitudinal studies involving a longer follow-up.     

Comparative studies on the dynamics of crosslinked insulin

Molecular dynamics simulations were carried out on an insulin crosslinked between the N-terminal A chain and the C-terminal B chain to form a so-called mini-proinsulin: N -^A1-N -^B29-diaminosuberoyl insulin (DASI). To investigate the influence of crosslinking on the dynamics of the insulin moiety, the bridge was removed from a transient DASI structure and simulation was carried on independently with the then unlinked (ULKI) as well as with the crosslinked species. The effects of crystal packing and quaternary interactions were checked by simulating both types of monomers and dimers known from the hexamer structure. All simulations were compared to previous ones of native insulin. DASI shows general similarity to the native simulations in most parts of the structure. Deviations are visible in the segments to which the bridge is directly connected, i.e. their flexibility is reduced. Upon removal of the bridge the ULKI simulations reapproach those of native insulin. The influence of the bridge spreads over the whole molecule, but all of its main structural features remain intact. The simulations suggest that the displacement of the C-terminal B chain of native insulin, considered important for receptor interaction, is prevented by the bridge, which also partially shields some binding residues. This is in accordance with the poor biological potency of A1-B29-crosslinked insulins.Abbreviations DASI-insulin(DASI) bovineN -^A1-N -^B29-di-aminosuberoyl insulin - ULK-insulin (ULKI) Native beef insulin with the bridge of DASI removed     

Generic level relationships of the papionini (cercopithecoidea)

Phylogenetic hypotheses for the Old World monkey tribe Papionini based on molecular data are incongruent with those inferred from previous morphological analyses. Morphologists have often inferred a close relationship between Mandrillus and Papio based on their overall similarity. Theropithecus has been variously proposed to be either quite distantly related to these two genera, their sister taxon, or anywhere in between. Molecular and chromosomal analyses on the other hand unambiguously group Theropithecus and Papio together to the exclusion of Mandrillus. Additionally, molecular and chromosomal analyses reveal that mangabeys (Cerocebus) are paraphyletic. Morphologists have acknowledged this possibility resurrecting the genus name Lophocebus for one group of mangabeys. A review and reanalysis of the morphological characters put forth by various researchers find little to contradict the consensus phylogeny derived from analysis of chromosomal banding, nuclear RNA restriction mapping, alpha and beta hemoglobin sequences, albumin and transferrin microcomplement fixation, DNA-DNA hybridization, repetitive DNA patterns, immunodiffusion, hemoglobin and adenylate kinase isozymes, and mitochondrial cytochrome oxidase subunit II DNA sequences. © 1994 Wiley-Liss, Inc.     

SUBSTITUTION PROCESSES IN MOLECULAR EVOLUTION. II. EXCHANGEABLE MODELS FROM POPULATION GENETICS

Substitution processes are of two sorts: origination processes record the times at which nucleotide mutations that ultimately fix in the population first appear, and fixation processes record the times at which they actually fix. Substitution processes may be generated by combining models of population genetics—here the symmetrical-neutral, overdominance, underdominance, TIM, and SAS-CFF models—with the infinite-sites, no-recombination model of the gene. This paper is mainly concerned with a computer simulation study of these substitution processes. The rate of substitution is shown to be remarkably insensitive to the strength of selection for models with strong balancing selection caused by the genealogical drift of mutations through alleles held in the population by selection. The origination process is shown to be more regular than Poisson for the overdominance, TIM, and SAS-CFF models but more clustered for the underdominance model. A class of point processes called Sawyer processes is introduced to help explain these observations as well as the observation that the times between successive originations are nearly uncorrelated. Fixation processes are shown to be more complex than origination processes, with regularly spaced bursts of multiple fixations. An approximation to the fixation process is described. One important conclusion is that protein evolution is not easily reconciled with any of these models without adding perturbations that recur on a time scale that is commensurate with that of molecular evolution.     

P-type ATPases of eukaryotes and bacteria: Sequence analyses and construction of phylogenetic trees

The amino acid sequences of 47 P-type ATPases from several eukaryotic and bacterial kingdoms were divided into three structural segments based on individual hydropathy profiles. Each homologous segment was (1) multiply aligned and functionally evaluated, (2) statistically analyzed to determine the degrees of sequence similarity, and (3) used for the construction of parsimonious phylogenetic trees. The results show that all of the P-type ATPases analyzed comprise a single family with four major clusters correlating with their cation specificities and biological sources as follows: cluster 1: Ca²⁺-transporting ATPases; cluster 2: Na⁺- and gastric H⁺-ATPases; cluster 3: plasma membrane H⁺-translocating ATPases of plants, fungi, and lower eukaryotes; and cluster 4: all but one of the bacterial P-type ATPases (specific for K⁺, Cd²⁺, Cu²⁺ and an unknown cation). The one bacterial exception to this general pattern was the Mg²⁺-ATPase of Salmonella typhimurium, which clustered with the eukaryotic sequences. Although exceptions were noted, the similarities of the phylogenetic trees derived from the three segments analyzed led to the probability that the N-terminal segments 1 and the centrally localized segments 2 evolved from a single primordial ATPase which existed prior to the divergence of eukaryotes from prokaryotes. By contrast, the C-terminal segments 3 appear to be eukaryotic specific, are not found in similar form in any of the prokaryotic enzymes, and are not all demonstrably homologous among the eukaryotic enzymes. These C-terminal domains may therefore have either arisen after the divergence of eukaryotes from prokaryotes or exhibited more rapid sequence divergence than either segment 1 or 2, thus masking their common origin. The relative rates of evolutionary divergence for the three segments were determined to be segment 2 < segment 1 < segment 3. Correlative functional analyses of the most conserved regions of these ATPases, based on published site-specific mutagenesis data, provided preliminary evidence for their functional roles in the transport mechanism. Our studies define the structural and evolutionary relationships among the P-type ATPases. They should provide a guide for the design of future studies of structure-function relationships employing molecular genetic, biochemical, and biophysical techniques. Correspondence to: M.H. Saier, Jr.     

Evaluation of “sequence-tagged-site” PCR products as molecular markers in wheat

The polymerase chain reaction (PCR) is an attractive technique for many genome mapping and characterization projects. One PCR approach which has been evaluated involves the use of randomly amplified polymorphic DNA (RAPD). An alternative to RAPDs is the sequence-tagged-site (STS) approach, whereby PCR primers are designed from mapped low-copy-number sequences. In this study, we sequenced and designed primers from 22 wheat RFLP clones in addition to testing 15 primer sets that had been previously used to amplify DNA sequences in the barley genome. Our results indicated that most of the primers amplified sequences that mapped to the expected chromosomes in wheat. Additionally, 9 of 16 primer sets tested revealed polymorphisms among 20 hexaploid wheat genotypes when PCR products were digested with restriction enzymes. These results suggest that the STS-based PCR analysis will be useful for generation of informative molecular markers in hexaploid wheat.Contribution no. J-2833 of the Montana Agric Exp Stn     

Classification of cultivated rices into indica and japonica types by the isozyme,RFLP and two milled-rice methods

Four methods for classifying cultivated rices (Oryza sativa L.) (including IR varieties) into indica and japonica types — waxy gene product in endosperm starch, glutelin ₃ molecular weight in milled rice, RFLP polymorphism at the Wx locus and Glaszmann's isozyme method — were compared. On the basis of the two endosperm traits and the RFLP method Glaszmann's group 1 (indica) was classified as mainly indica and intermediate groups 2, 3 and 4 as exclusively indica. However, the endosperm traits classified Glaszmann's group 5 as mainly indica, while the RFLP method classified it as japonica. The RFLP waxy gene probe was closest to the isozyme method in classifying group 6 as japonicas; the waxy gene product gave mainly indica reaction even in group 6, and the glutelin ₃ method was intermediate. All IR rices were classified as being indica on the basis of Wx gene product and by Glaszmann's method, but a few were classified as japonica by the glutelin ₃ method and by the RFLP waxy gene probe.     

QTL analysis: a simple ‘marker-regression’ approach

A method to locate quantitative trait loci (QTL) on a chromosome and to estimate their additive and dominance effects is described. It applies to generations derived from an F₁ by selfing or backcrossing and to doubled haploid lines, given that marker genotype information (RFLP, RAPD, etc.) and quantitative trait data are available. The method involves regressing the additive difference between marker genotype means at a locus against a function of the recombination frequency between that locus and a putative QTL. A QTL is located, as by other regression methods, at that point where the residual mean square is minimised. The estimates of location and gene effects are consistent and as reliable as conventional flanking-marker methods. Further applications include the ability to test for the presence of two, or more, linked QTL and to compare different crosses for the presence of common QTL. Furthermore, the technique is straightforward and may be programmed using standard pc-based statistical software.     

Expression of sunflower low-molecular-weight heat-shock proteins during embryogenesis and persistence after germination: localization and possible functional implications

We isolated and sequenced Ha hsp 17.9, a DNA complementary (cDNA) of dry-seed stored mRNA that encodes a low-molecular-weight heat-shock protein (LMW HSP). Sequence analysis identified Ha hsp17.9, and the previously reported Ha hsp17.6, as cDNAs encoding proteins (HSP17.6 and HSP17.9) which belong to different families of cytoplasmic LMW HSPs. Using specific antibodies we observed differential expression of both proteins during zygotic embryogenesis under controlled environment, and a remarkable persistence of these LMW HSPs during germination. Immuno-blot analysis of HSP17.9 proteins in two-dimensional gels revealed that the polypeptides expressed in embryos were indistinguishable from LMW HSPs expressed in vegetative tissues in response to water deficit; but they appeared different from homologeous proteins expressed in response to thermal-stress. Tissue-print immunolocalization experiments showed that HSP17.9 and HSP17.6 were homogeneously distributed in every tissue of desiccation-tolerant dry seeds and young seedlings under non-stress conditions. These results demonstrate developmental regulation of specific, cytoplasmic, plant LMW HSPs, suggesting also their involvement in water-stress tolerance.