Complications and concurrent disease associated with canine hyperadrenocorticism

In untreated hyperadrenocorticism, clinical problems may result from metastasis of an adrenocortical carcinoma, growth of a pituitary tumor, or complications associated with sustained hypercortisolemia itself, such as hypertension, cardiovascular disease, thromboembolism, glucose intolerance, and increased susceptibility to infection. This article discusses the origin, diagnosis, and treatment of the many complications associated with hyperadrenocorticism.

Who are the 'low energy reporters' in the dietary and nutritional survey of British adults?

BACKGROUND

Underreportin in dietary surveys is a potential source of bias in studies of diet and disease. The aim of this study was to identify characteristics of men and women participants in the Dietary and Nutritional Survey of British Adults (DNSBA) who stated that they were neither slimming nor ill, and who reported an average energy intake over a 7-day period below 1.2 times estimated basal metabolic rate (BMR), termed here 'low energy reporters' (LER).

METHODS

In all, 2197 men and women aged 16-64 years participated in the DNSBA. Dietary intake was assessed using the 7-day weighed intake method. Their BMR was estimated using predictive equations based upon age, sex and body weight.

RESULTS

Compared with non-LER, LER had higher mean ratios of urinary urea nitrogen to dietary nitrogen and urinary potassium to dietary potassium, indicating that, as a group, LER were underreporting at least for protein and potassium intakes. Overall LER were overrepresented among the manual social classes, smokers, and self-reported non-alcohol drinkers, and were on average heavier than non-LER. There was indication of differential reporting of foods and differences in macronutrient and micronutrient densities between LER and non-LER.

CONCLUSION

These results suggest that LER may be overrepresented within specific population subgroups and that underreporting bias may not be food and nutrient neutral. This has implications for the design and interpretation of studies of diet and disease.

Mechanistic studies of R67 dihydrofolate reductase. Effects of pH and an H62C mutation

R67 dihydrofolate reductase (DHFR) is encoded by an R-plasmid, and expression of this enzyme in bacteria confers resistance to the antibacterial drug, trimethoprim. This DHFR variant is not homologous in either sequence or structure with chromosomal DHFRs. The crystal structure of tetrameric R67 DHFR indicates a single active site pore that traverses the length of the molecule (Narayana, N., Matthews, D. A., Howell, E. E., and Xuong, N.-H. (1995) Nat. Struct. Biol. 2, 1018-1025). A pH profile of enzyme activity in R67 DHFR displays an acidic pKa that is protein concentration-dependent. This pKa describes dissociation of active tetramer into two relatively inactive dimers upon protonation of His-62 and the symmetry-related His-162, His-262, and His-362 residues at the dimer-dimer interfaces. Construction of an H62C mutation results in stabilization of the active tetramer via disulfide bond formation at the dimer-dimer interfaces. The oxidized, tetrameric form of H62C R67 DHFR is quite active at pH 7, and a pH profile displays increasing activity at low pH. These results indicate protonated dihydrofolate (pKa = 2.59) is the productive substrate and that R67 DHFR does not possess a proton donor.

Multiple antigenic peptides designed to structurally related Drosophila peptides

We have isolated TDVDHVFLRFamide (DMS), FDDYGHMRFamide (DSK), and DPKQDFMRFamide from Drosophila melanogaster. These peptides, structurally related by a common C-terminus -XRFamide, where X = L or M, are encoded by three different genes. To determine cellular expression, we have generated antisera to multiple antigenic peptides and performed double-label immunofluorescence using antisera raised in the same species host animal. Our results indicate that DMS and DSK immunoreactive materials have unique, non-overlapping expression patterns, while DMS and DPKQDFMRFamide immunoreactive materials colocalize in two superior protocerebrum neurons, and DSK and DPKQDFMRFamide immunoreactive materials colocalize in one superior protocerebrum neuron, one subesophageal ganglion neuron, and three thoracic ganglia neurons.

Cultural issues in death and dying

Although all of us experience death, not all of us think about death or respond to death the same way. This study begins to explore how cultural traditions, education, and tenure in Hawaii impact views of advanced directives, organ donation, suicide, and euthanasia. This information is useful to physicians who need to engage patients and families in discussions about death and end-of-life decision making.

Serum fructosamine concentration as an index of glycemia in cats with diabetes mellitus and stress hyperglycemia

The purpose of this study was to evaluate fructosamine concentrations in clinically healthy cats, sick cats with stress hyperglycemia, and untreated diabetic cats to determine the usefulness of this test in diagnosing diabetes mellitus in cats, and in differentiating the disease from stress-induced hyperglycemia. In addition, we evaluated if the degree of glycemic control in cats treated for diabetes influenced their serum fructosamine concentrations. In the 14 sick cats with stress hyperglycemia, the median serum fructosamine concentration (269 mumol/L) was not significantly different from the median value in the 26 clinically normal cats (252 mumol/L). Two of the 14 cats with stress hyperglycemia (14.3%) had serum fructosamine concentrations above the upper limit of the reference range (175 to 400 mumol/L); on the basis of these results, the test specificity was calculated as 0.86. In 30 cats with untreated diabetes mellitus, the median serum fructosamine concentration was 624 mumol/L, markedly higher than the value in either the normal cats or the cats with stress hyperglycemia. All but 2 of the 30 untreated diabetic cats (6.7%) had serum fructosamine concentration above the upper limit of the reference range; on the basis of these results, the sensitivity of serum fructosamine concentration as a diagnostic test for diabetes mellitus was 0.93. When 30 diabetic cats receiving treatment were divided into 3 groups according to their response to treatment (i.e., poor, fair, and good), the 16 cats that had a good response to treatment had significantly lower serum concentrations of both glucose and fructosamine compared with cats that had either a fair or poor response to treatment. A significant correlation (rs = .70, n = 100, P < .001) was found between serum concentrations of glucose and fructosamine. Results of this study indicate that quantification of serum fructosamine concentration is a meaningful test for the diagnosis of diabetes, for differentiating diabetes from stress hyperglycemia; and for monitoring the metabolic control in treated diabetic cats.

Inverse relation of dietary protein markers with blood pressure. Findings for 10,020 men and women in the INTERSALT Study. INTERSALT Cooperative Research Group. INTERnational study of SALT and blood pressure

BACKGROUND

The purpose of this study was to assess relations to blood pressure (BP) in individuals of markers of dietary protein in their 24-hour urine collections.

METHODS AND RESULTS

INTERSALT (INTERnational study of SALT and blood pressure) was a cross-sectional study of 10020 men and women aged 20 to 59 years in 52 population-based samples in 32 countries worldwide, with quality-controlled standardized procedures and assessment of multiple possible confounders. Three measurements of dietary protein in 24-hour urine of each individual participant were studied: total nitrogen and urea as indexes of total protein intake, and sulfate as an index of sulfur-containing dietary amino acids. Repeat examination was performed in a random 8% of participants to assess reliability and to correct for regression-dilution bias. Significant independent inverse relationships were found between BP (systolic and diastolic) and both 24-hour urinary total nitrogen and urea nitrogen, with adjustment for age, sex, alcohol intake, body mass, and 24-hour urinary sodium, potassium, calcium, and magnesium. With adjustment for regression-dilution bias, it was estimated that systolic and diastolic BP were on average 3.0 and 2.5 mm Hg lower, respectively, for persons with dietary total protein intake 30% above the overall mean than for those whose dietary protein intake was 30% below the overall mean (12.94 versus 6.96 g/d urinary total nitrogen, equivalent to 81 versus 44 g/d dietary protein, respectively). For the association of these markers with diastolic BP, results were similar for younger (20- to 39-year-old) and older (40- to 59-year-old) persons and for women and men. For their relation to systolic BP, regression coefficients were larger both for those aged 40 to 59 years than for those aged 20 to 39 years and for women than for men. Nonsignificant inverse relations were recorded for urinary sulfate and BP.

CONCLUSIONS

These INTERSALT findings lend support to the hypothesis that higher dietary protein intake has favorable influences on BP.

Dietary salt, nitrate and stomach cancer mortality in 24 countries. European Cancer Prevention (ECP) and the INTERSALT Cooperative Research Group

BACKGROUND

High salt and nitrate intake are considered as risk factors for stomach cancer, but little is known about possible interactions. This ecological study examines the respective importance of both factors for stomach cancer mortality at the population level using data obtained under standardized conditions and with biochemical analyses performed in the same laboratories.

METHODS

Randomly selected 24-hour urine samples from 39 populations, sampled from 24 countries (N = 5756 people for sodium, 3303 for nitrate) were obtained from the INTERSALT study. Median sodium and nitrate levels were age- and sex-standardized between ages 20-49 years and averaged per country. Ecological correlation-regression analyses were done in relation to national stomach cancer mortality rates.

RESULTS

The Pearson correlation of stomach cancer mortality with sodium for the 24 countries was: 0.70 in men and 0.74 in women (both P < 0.001) and with nitrate: 0.63 (P = 0.001) in men and (P < 0.005) in women. In multiple regression of stomach cancer mortality, using sodium and nitrate as independent variables the adjusted R2 was 0.61 in men and 0.54 in women (both P < 0.001). Addition of the interaction term (sodium x nitrate) to the previous model increased the adjusted R2 to 0.77 in men, and to 0.63 in women. The analysis of this model showed that the importance of nitrate as risk factor for stomach cancer mortality increased markedly with higher sodium levels. However, the relationship of stomach cancer mortality with sodium was always stronger than with nitrate.

CONCLUSIONS

Salt intake, measured as 24-hour urine sodium excretion, is likely the rate-limiting factor of stomach cancer mortality at the population level.

Twenty-four hour urinary nitrate excretion in 48 populations from 30 countries: an ECP-INTERSALT collaborative study

BACKGROUND

There is considerable interest in the possible role of nitrate in gastric carcinogenesis, but little information on nitrate intake around the world. This is the first study to give comprehensive standardised data on nitrate excretion as a marker of intake, using 48 worldwide population samples.

METHODS

Urinary nitrate excretion has been shown to be a valid measure of nitrate intake in people under 50. This report presents data on 24-hour urinary nitrate excretion from urine collections obtained in the INTERSALT study, based on random samples of men and women aged 20-49 from each of 48 population samples in 30 countries.

RESULTS

There was large variation in urinary nitrate excretion both within and between samples; within-sample (individual) distributions tended to be skewed towards higher values. Median values of the samples ranged from 0.42 mmol/day (Labrador, Canada) to 3.52 (Beijing, People's Republic of China) in men and 0.44 mmol/day (Colombia) to 3.44 (Beijing) in women. Overall, median values were higher in men than women by 11% on average (higher in men in 37 of 48 population samples). Comparison by geographical region of median values for men and women combined showed relatively low values in the samples in North America and Northern Europe (range 0.46-0.88 mmol/day), slightly higher values in Western Europe and Africa (0.68-1.11), and intermediate to high values in Southern Europe, Eastern and Central Europe and India (0.86-2.47). The highest median values were found in the Far Eastern samples (up to 3.48). Median values in the Central and South American samples ranged from 0.48 mmol/day (Colombia) to 1.37 (Xingu Indians of Brazil, and Argentina).

CONCLUSIONS

For the first time, these data give standardized information on urinary nitrate excretion from different geographical regions of the world, and provide a basis for the further exploration of the role of nitrate in the aetiology of disease in human populations.

Intersalt revisited: further analyses of 24 hour sodium excretion and blood pressure within and across populations. Intersalt Cooperative Research Group

OBJECTIVES

To assess further the relation in Intersalt of 24 hour urinary sodium to blood pressure of individuals and populations, and the difference in blood pressure from young adulthood into middle age.

DESIGN

Standardised cross sectional study within and across populations.

SETTING

52 population samples in 32 countries.

SUBJECTS

10,074 men and women aged 20-59.

MAIN OUTCOME MEASURES

Association of sodium and blood pressure from within population and cross population multiple linear regression analyses with multivariate correction for regression dilution bias. Relation of sample median daily urinary sodium excretion to difference in blood pressure with age.

RESULTS

In within population analyses (n = 10,074), individual 24 hour urinary sodium excretion higher by 100 mmol (for example, 170 v 70 mmol) was associated with systolic/diastolic blood pressure higher on average by 3/0 to 6/3 mm Hg (with and without body mass in analyses). Associations were larger at ages 40-59. In cross population analyses (n = 52), sample median 24 hour sodium excretion higher by 100 mmol was associated with median systolic/diastolic pressure higher on average by 5-7/2-4 mm Hg, and estimated mean difference in systolic/diastolic pressure at age 55 compared with age 25 greater by 10-11/6 mm Hg.

CONCLUSIONS

The strong, positive association of urinary sodium with systolic pressure of individuals concurs with Intersalt cross population findings and results of other studies. Higher urinary sodium is also associated with substantially greater differences in blood pressure in middle age compared with young adulthood. These results support recommendations for reduction of high salt intake in populations for prevention and control of adverse blood pressure levels.

Localization of myosuppressinlike peptides in the hypocerebral ganglion of two blood-feeding flies: horn fly and stable fly (Diptera:Muscidae)

The insect peptides leucomyosuppressin (pEDVDHVFLRFamide) and dromyosuppressin (TDVDHVFLRFamide) have identical chemical sequences with the exception of the N-terminal amino acid; both inhibit spontaneous contraction of insect visceral muscles. Neurons in the hypocerebral ganglion of horn fly, Hematobia irritans (L.), and stable fly, Stomoxys calcitrans (L.), were found to contain material immunoreactive to antiserum produced against the C-terminal of leucomyosuppressin, but not to the N-terminal of dromyossuppressin. Two large lateral clusters containing 8 cells, linked dorsally and ventrally by 2 chains of 6 cells, encircled the anterior surface of the proventriculus and were immunoreactive of leucomyosuppressin and FMRFamide antisera. Axons from these cells were traced to the wall of the aorta and over the surface of the proventriculus. Ultrastructural analysis revealed these cells contained a singular type of elementary secretory granule that contained material of relatively low electron density, both in the cell body and at the axon terminals.

Spatial and temporal immunocytochemical analysis of drosulfakinin (Dsk) gene products in the Drosophila melanogaster central nervous system

The spatial and temporal distribution of three peptides, DSK I, DSK II, and DSK 0, encoded by the Drosophila melanogaster drosulfakinin (Dsk) gene, have been examined in the central nervous system. DSK I and DSK II have a -RFamide C-terminus and are structurally similar to sulfakinin peptides; in contrast, DSK 0 contains -SFamide and is not structurally similar to sulfakinins. Antisera specificities were determined by the design of the antigens and confirmed by dot blot analysis and preincubation with peptides prior to their use in immunocytochemistry. The distribution of immunoreactivity suggests that all three DSK peptides are processed from the polypeptide precursor and expressed in many of the same cells. Expression was observed at all developmental stages with an increase in the level of staining and the number of immunoreactive cells as development progresses. Cells in the brain lobe, optic lobe, subesophageal ganglion, thoracic ganglia, and the eighth abdominal neuromere contain DSK-immunoreactive materials. Immunoreactive fibers project from some cells and extend into the brain and ventral ganglion with regions of extensive arborization. DSK 0 immunoreactivity provides initial evidence for the presence of a -SFamide peptide in neural tissue. The observed expression of DSK-immunoreactive materials throughout development in numerous cells of the central nervous system suggests that DSK peptides may serve as hormones, modulators, or transmitters involved in several functions.

Spatial and temporal analysis of the Drosophila FMRFamide neuropeptide gene product SDNFMRFamide: evidence for a restricted expression pattern

The expression of SDNFMRFamide, one of five different FMRFamide-containing peptides encoded by the Drosophila melanogaster FMRFamide gene, has been determined. To study expression, we generated antisera to the N-terminus of SDNFMRFamide to avoid crossreactivity with FMRFamide-containing peptides. The antisera were purified and the specificity characterized. SDNFMRFamide immunoreactive material is present in the central nervous system throughout development. Immunoreactivity is first observed in embryonic neural tissue in a cluster of cells in the subesophageal ganglion and immunoreactive fibers projecting from these cells to the brain and ventral ganglion. This pattern of expression is also observed in neural tissue dissected from larva, pupa, and adult. Double-labelling experiments indicate that cells recognized by SDNFM-antisera are also stained with FMRFamide antisera. Based on position, SDNFMRFamide immunoreactive material is expressed in a limited number of cells that contain the FMRFamide polypeptide precursor. This finding suggests that the Drosophila FMRFamide precursor undergoes differential post-translational processing.

Human alanyl-tRNA synthetase: conservation in evolution of catalytic core and microhelix recognition

The class II Escherichia coli and human alanyl-tRNA synthetases cross-acylate their respective tRNAs and require, for aminoacylation, an acceptor helix G3:U70 base pair that is conserved in evolution. We report here the primary structure and expression in the yeast Pichia of an active human alanyl-tRNA synthetase. The N-terminal 498 amino acids of the 968-residue polypeptide have substantial (41%) identity with the E. coli protein. A closely related region encompasses the class-defining domain of the E. coli enzyme and includes the part needed for recognition of the acceptor helix. As a result, previously reported mutagenesis, modeling, domain organization, and biochemical characterization on the E. coli protein appear valid as a template for the human protein. In particular, we show that both the E. coli enzyme and the human enzyme purified from Pichia aminoacylate 9-base pair RNA duplexes whose sequences are based on the acceptor stems of either E. coli or human alanine tRNAs. In contrast, the sequences of the two enzymes completely diverge in an internal portion of the C-terminal half that is essential for tetramer formation by the E. coli enzyme, but that is dispensable for microhelix aminoacylation. This divergence correlates with the expressed human enzyme behaving as a monomer. Thus, the region of close sequence similarity may be a consequence of strong selective pressure to conserve the acceptor helix G3:U70 base pair as an RNA signal for alanine.

Comparison of the activity of meropenem with that of other agents in the treatment of intraabdominal, obstetric/gynecologic, and skin and soft tissue

Meropenem, a new carbapenem with improved stability in the presence of human dehydropeptidase-I[1], was evaluated in three prospective, multicenter, randomized, controlled clinical trials in North America. We compared the in vitro activity of meropenem and conventional antimicrobial agents for the treatment of intraabdominal, obstetric/gynecologic, and skin or soft tissue infections as well as the responses of pathogens to all of these agents. The trials of the drug for intraabdominal infection were double blind, and those for the obstetric/gynecologic and soft tissue infections were open labeled. Overall, MICs of meropenem for pathogens were lower, and the pathogen response rates were at least comparable to those for the following comparative agents: clindamycin plus tobramycin (for intraabdominal infections); clindamycin plus gentamicin (for obstetric/gynecologic infections); and imipenem and cilastatin (for skin or soft tissue infections). Meropenem has high in vitro potency and covers a broad spectrum of anaerobic and aerobic pathogens.

Complications and concurrent disease associated with diabetic ketoacidosis and other severe forms of diabetes mellitus

The more serious forms of diabetes mellitus such as diabetic ketoacidosis (DKA) and hyperosmolar nonketotic syndrome (HNKS) are precipitated commonly by other underlying disease processes. In addition, the treatment of these severe forms of diabetes mellitus are often complicated by therapy. This article discusses common concurrent disorders and therapeutic complications seen in both canine and feline diabetes mellitus.

Cellular expression of the Drosophila melanogaster FMRFamide neuropeptide gene product DPKQDFMRFamide. Evidence for differential processing of the FMRFamide polypeptide precursor

DPKQDFMRFamide is one of five different FMRFamide-containing peptides encoded in the Drosophila FMRFamide gene. To study the cellular expression of DPKQDFMRFamide, we have generated antisera to DPKQD, the N-terminal sequence of the peptide, to avoid crossreactivity with other -FMRFamide-containing peptides. The antisera were purified and the specificity characterized. DPKQDFMRFamide immunoreactive material is first observed in the embryonic central nervous system (CNS) in one cell of the subesophageal ganglion and one cell in each of the three thoracic ganglia. This pattern of expression is observed in larval, pupal, and adult neural tissue, albeit with increased signal intensity. In larva, pupa, and adult, additional cells in the superior protocerebrum, a thoracic ganglion, and an abdominal ganglion express DPKQDFMRFamide immunoreactive material. Immunoreactivity is observed in a cell in the lateral protocerebrum of pupa and adult and cells in the optic lobe of adult. No immunoreactive material was observed in gut tissue. DPKQDFMRFamide antisera stain a subset of cells previously identified by in situ hybridization and immunocytochemistry to express the FMRFamide transcript and polypeptide precursor. These data suggest that the Drosophila FMRFamide polypeptide precursor undergoes differential processing to produce DPKQDFMRFamide immunoreactive material in a limited number of cells expressing the FMRFamide precursor.

A motif in human histidyl-tRNA synthetase which is shared among several aminoacyl-tRNA synthetases is a coiled-coil that is essential for enzymatic activity and contains the major autoantigenic epitope

In myositis, disease-specific autoantibodies may be directed against an aminoacyl-tRNA synthetase, usually histidyl-tRNA synthetase. To explore the basis for this phenomenon, we have made recombinant histidyl-tRNA synthetase in the baculovirus system. It was enzymatically active and recognized by human autoantibodies. A truncated protein lacking the first 60 amino acids was inactive as an antigen and as an enzyme. This region is within the first two exons, is predicted to have a coiled-coil configuration, and is found in some other synthetases but not in Escherichia coli or yeast histidyl-tRNA synthetase. Circular dichroism showed that the peptides from this region (amino acids 1-60 and 1-47) have the predicted high alpha-helical content, but smaller fragments (1-30, 14-45, and 31-60) do not. The peptides with a high alpha-helical content could inhibit autoantibodies almost completely, whereas the smaller peptides were unable to do so. The amino acid sequence of this coiled-coil domain in human histidyl-tRNA synthetase resembles the sequence of the extended this coiled-coil arm near the NH2 terminus of bacterial seryl-tRNA synthetase as well as similar regions in some eukaryotic aminoacyl-tRNA synthetases, raising the possibility that this domain serves a similar tRNA-stabilizing role and has been preserved from a common ancestor.

Concurrent illness and complications associated with canine hyperadrenocorticism

Complications associated with canine HAC include thromboembolism, infection, diabetic mellitus, pancreatitis, or growing pituitary tumor. The serious consequences of the multisystemic effects of cortisol excess show the need for careful examination and monitoring of animal patients with HAC so that the many associated complications may be recognized, treated, and in some cases prevented.

Accumulation of glutamate by Salmonella typhimurium in response to osmotic stress

Salmonella typhimurium accumulates glutamate in response to osmotic stress. Cells in aerobic exponential growth have an intracellular pool of approximately 125 nmol of glutamate mg of protein-1. When cells were grown in minimal medium with 500 mM NaCl, KCl, or sucrose, 290 to 430 nmol of glutamate was found to accumulate. Values were lower when cells were harvested in stationary phase. Cells were grown in conventional medium, harvested, washed, resuspended in the control medium or in medium with osmolytes, and aerated for 1 h. With aeration, glutamate was found to accumulate at levels comparable to those observed in exponential cultures. Antibiotics inhibiting protein synthesis did not affect glutamate accumulation when cells were aerated. Strains with mutations in glutamate synthase (glt) or in glutamate dehydrogenase (gdh) accumulated nearly normal levels of glutamate under these conditions. A double (gdh glt) mutant accumulated much less glutamate (63.9 nmol mg of protein-1), but a 1.9-fold excess accumulated when cells were aerated with osmotic stress. Methionine sulfone, an inhibitor of glutamate synthase, did not prevent accumulation of glutamate in cells aerated with osmotic stress. Glutamate dehydrogenase is thought to have minimum activity when ammonium is limiting. Resuspending cells with limiting ammonium reduced glutamate production but did not eliminate accumulation of excess glutamate when cells were osmotically stressed. Amino oxyacetic acid, an inhibitor of transamination reactions, did not prevent accumulation of excess glutamate.(ABSTRACT TRUNCATED AT 250 WORDS)