Comparison of production-related responses to hyperinsulinemia and hypoglycemia induced by clamp procedures or heat stress of lactating dairy cattle.

Hyperinsulinemia concurrent with hypoglycemia is one of a myriad of physiological changes typically experienced by lactating dairy cows exposed to heat stress, the consequences of which are not yet well defined or understood. Therefore, the objective of this experiment was to separate the production-related effects of hyperinsulinemia with hypoglycemia from those of a hyperthermic environment. Multiparous lactating Holstein cows (n = 23; 58 ± 4 d in milk, 3.1 ± 0.3 lactations) were housed in temperature-controlled rooms and all were subjected to 4 experimental periods as follows: (1) thermoneutral (TN; temperature-humidity index of 65.1 ± 0.2; d 1-5), (2) TN + hyperinsulinemic-hypoglycemic clamp (HHC; insulin infused at 0.3 µg/kg of BW per h, glucose infused to maintain 90 ± 10% of baseline blood glucose for 96 h; d 6-10), (3) heat stress (HS; temperature-humidity index of 72.5 ± 0.2; d 16-20), and (4) HS + euglycemic clamp (EC; glucose infused to reach 100 ± 10% of TN baseline blood glucose for 96 h; d 21-25). Cows were fed and milked twice daily. Feed refusals were collected once daily for calculation of daily dry matter intake, and milk samples were collected at the beginning and end of each period for component analyses. Circulating insulin concentrations were measured in daily blood samples, whereas glucose concentrations were measured more frequently and variably in association with clamp procedures. Rectal temperatures and respiration rates were greater during HS than TN, as expected, and states of hyperinsulinemia and hypoglycemia were successfully induced by the HHC and high ambient temperatures (HS and EC). Feed intake differed based upon thermal environment as it was similar during TN and HHC periods, and declined for HS and EC. Milk production was not entirely reflective of feed intake as it was greatest during TN, intermediate during HHC, and lowest during HS and EC. All milk components differed with the experimental period, primarily in response to the thermal environment. Interestingly, TN baseline glucose concentrations were highly correlated with the change in glucose from TN to HS, and were related to glycemic status during HS. Furthermore, although few in number, those cows that failed to become hypoglycemic during HS tended to have a greater reduction in milk yield. The work presented here addresses a critical knowledge gap by broadening our understanding of the physiological response to heat stress and the related changes in glycemic state. This broadened understanding is fundamental for the development of novel, innovative management strategies as the dairy industry is compelled to become increasingly efficient in spite of global warming.

The effects on children of depressed mothers' remission and relapse over 9 months.

BACKGROUND: The high rate of depression among children of depressed mothers is well known. Suggestions that improvement in maternal acute depression has a positive effect on the child have emerged. However, data on the mechanisms of change have been sparse. The aim was to understand how remission and relapse in the mother might explain the changes in the child's outcome. METHOD: Participants were 76 depressed mothers who entered into a medication clinical trial for depression and 135 of their eligible offspring ages 7-17 years. The mothers and children were assessed at baseline and periodically over 9 months by independent teams to understand the relationship between changes in children's symptoms and functioning and maternal remission or relapse. The main outcome measures were, for mothers, the Hamilton Depression Rating Scale (HAMD), the Social Adjustment Scale (SAS) and the Parental Bonding Instrument (PBI) and, for children, the Children's Depression Inventory (CDI), the Columbia Impairment Scale (CIS), the Multidimensional Anxiety Scale for Children (MASC) and the Children's Global Assessment Scale (CGAS). RESULTS: Maternal remission was associated with a decrease in the child's depressive symptoms. The mother's subsequent relapse was associated with an increase in the child's symptoms over 9 months. The effect of maternal remission on the child's improvement was partially explained by an improvement in the mother's parenting, particularly the change in the mother's ability to listen and talk to her child, but also reflected in her improvement in parental bonding. These findings could not be explained by the child's treatment. CONCLUSIONS: A depressed mother's remission is associated with her improvement in parenting and a decrease in her child's symptoms. Her relapse is associated with an increase in her child's symptoms.

Human continuous glucose monitors for measurement of glucose in dairy cows.

If validated for use in dairy cattle, interstitial continuous glucose monitors (CGMs) could be easily implemented, informative tools for research, clinical, and perhaps even on-farm applications. To evaluate their efficacy, 2 experiments were conducted, during which lactating Holstein cows were fit with indwelling jugular catheters, as well as FreeStyle Libre (FSL; Abbott) and Dexcom G6 (DexCom Inc.) CGMs secured either behind their polls, lateral to their ears, or beneath their pin bones on their upper rear legs. During the first experiment, blood (measured with a handheld glucometer) and interstitial glucose measurements were collected from 13 cows every 4 h for 96 h. In the second experiment, the same measurements were collected from 8 cows every 15 min for 6 h. At the mid-point of the sampling period (3 h), cows received a bolus dose of dextrose to facilitate comparisons across a broad range of glucose concentrations. Results from both experiments determined that functional longevity of the sensors was greatest for those sensors secured near the ear. Likewise, interstitial measurements from the ear sensors were most closely correlated with blood glucose concentrations (r = 0.82 and r = 0.71 for FSL ear and Dexcom G6 ear, respectively). Unfortunately, accuracy calculated as absolute relative error was low, at 60.7% or less. As a result of the low accuracy, even though both ear sensors detected an increase in glucose concentrations following the bolus dose, neither produced results exactly matching blood glucose measurements. The results of this work indicate that the FSL and Dexcom G6 CGMs are not currently capable of replacing blood-based glucose measurements.

Contribution of serum inflammatory markers to changes in bone mineral content and density in postmenopausal women: a 1-year investigation.

Bone formation and resorption are influenced by inflammatory processes. We examined the relationships among inflammatory markers and bone mineral content (BMC) and density (BMD) and determined the contribution of inflammatory markers to 1-yr changes in BMC and BMD in healthy postmenopausal women. This analysis included 242 women at baseline from our parent Soy Isoflavones for Reducing Bone Loss project who were randomly assigned to 1 of 3 treatment groups: placebo, 80 mg/d soy isoflavones, or 120 mg/d soy isoflavones. BMD and BMC from the lumbar spine (LS), total proximal femur (hip), and whole body were measured by dual energy X-ray absorptiometry and the 4% distal tibia by peripheral quantitative computed tomography. Serum inflammatory markers (C-reactive protein, interleukin [IL]-1 beta, IL-6, tumor necrosis factor-alpha [TNF-alpha], and white blood cell count [WBC]) were measured at baseline, 6, and 12 mo. Because of attrition or missing values, data analysis at 12 mo includes only 235 women. Significant associations among IL-6, TNF-alpha, and WBC were observed with percent change in LS, hip, and whole body BMC and BMD. Multiple regression analysis indicated that in combination inflammatory markers accounted for 1.1-6.1% of the variance to the observed 12-mo changes in BMC and BMD. Our results suggest that modifying inflammatory markers, even in healthy postmenopausal women, may possibly reduce bone loss.

AUG is the only initiation codon in eukaryotes.

An analysis of mutants of the yeast Saccharomyces cerevisiae indicates that AUG is the sole codon capable of initiating translation of iso-1-cytochrome c. This result with yeast and the sequence results of numerous eukaryotic genes indicate that AUG is the only initiation codon in eukaryotes; in contrast, results with Escherichia coli and bacteriophages indicate that both AUG and GUG are initiation codons in prokaryotes. The difference can be explained by the lack of the t6 A hypermodified nucleoside (N-[9-(beta-D-ribofuranosyl)purin-6-ylcarbamoyl]threonine) in prokaryotic initiator tRNA and its presence in eukaryotic initiator tRNA.

Multiple base-pair mutations in yeast.

The nucleotide changes associated with both forward and reverse mutations at the CYC1 locus in the yeast Saccharomyces cerevisiae have been investigated by sequencing the mutated gene product, iso-1-cytochrome c and, more directly, by sequencing appropriate DNA segments. Although the majority of these mutations are the result of single base-pair changes, approximately 10% are the result of multiple mutations and these occur predominantly at certain sites and with certain patterns. Most multiple base-pair changes occur within 20 nucleotides of each other and are generally within six nucleotides. On the basis of the frequencies and patterns of mutations, these nucleotide changes are considered to have occurred as single, concerted events, rather than as multiple independent mutations. Analysis of these mutations indicates that multiple base-pair changes can arise by widely differing mechanisms. We have recognized the following classes of mutations: multiple base-pair changes that yield (1) direct repeats or (2) inverted repeats of local DNA sequences; (3) substitutions of two tandem base-pairs; (4) frameshift and contiguous single base-pair substitutions; and (5) recombination of the CYC1 gene with a non-allelic gene, resulting in alterations within contiguous segments that can be over 150 nucleotides in length. Some of the multiple base-pair changes do not fall into any of these categories. We suggest mechanisms to account for each of these five classes.

Yeast amber suppressors corresponding to tRNA3Leu genes.

Amber suppressors previously isolated from the yeast Saccharomyces cerevisiae and belonging to the same phenotypic class (Liebman et al., 1976) were assigned to nine different linkage groups named SUP52 through SUP60. One of these suppressors, SUP52, had been shown to cause the insertion of leucine and had been genetically mapped (Liebman et al., 1977). The following additional amber suppressors were mapped: SUP53 maps near the centromere of chromosome III closely linked to leu2; SUP54 maps on chromosome VII, 6 cM distal to trp5; SUP56 maps on chromosome I, 5.4 cM distal to ade1; SUP57 maps on chromosome VI, closely linked to met10; and SUP58 maps on the left arm of chromosome XI, loosely linked to met14. We show by protein analysis that like SUP52, the suppressors SUP53 through SUP56 are leucine-inserters. Furthermore, by hybridization with a cloned tRNA3Leu probe we demonstrate that at least SUP53, SUP54, SUP55 and SUP56 contain mutations in redundant tRNA3Leu genes because they each generate a new XbaI site in a DNA fragment encompassing a tRNA3Leu gene. These new XbaI sites are predicted by the known sequences of tRNA3Leu genes if the CAA anticodon mutates to the amber suppressing anticodon CTA. It is likely that each of the nine suppressors in this phenotypic class contain similar mutations in different tRNA3Leu genes since we find that there are approximately nine unlinked redundant copies of tRNA3Leu genes in haploid strains.

Variation of mutagenic action on nonsense mutants at different sites in the iso-1-cytochrome c gene of yeast.

Three ochre and two amber mutants in yeast have been definitively identified by the amino acid replacements in iso-1-cytochromes c from intragenic revertants. Except for rare and sometimes unusual changes, all of the replacements were single amino acids whose codons differed from UAA or UAG by one base. These assignments, which were based on the absence of tryptophan replacements in ochre revertants, could be corroborated from the studies of two groups of suppressors that were shown to act on either the ochre or amber mutants. All five nonsense mutants are located at different sites in the cyc1 gene and all are at sites that can be occupied by amino acids having a wide range of structures. The relative frequencies of the amino acid replacements indicate that identical codons located at different sites may respond differently to a mutagenic agent. Notably glutamine replacements occurred almost exclusively in UV-induced revertants of only one ochre mutant cyc1-9, but not at all or at reduced proportions in the others. Similarly, lysine replacements occurred almost exclusively in the NA-induced revertants of only the ochre mutant cyc1-72, but not at all in the others. These and other results reveal that mutation of A.T base pairs by UV and nitrous acid are dependent upon the location of the codon within the gene as well as the location of the base pair within the codon. From these findings, it appears as if the type of base-pair changes induced by UV and nitrous acid are strongly influenced by adjacent nucleotide sequences.

Isolation and characterization of amber suppressors in yeast.

Nonsense suppressors were obtained in a haploid yeast strain containing eight nutritional mutations, that are assumed to be amber or ochre, and the cyc1-179 amber mutation that has a UAG codon corresponding to position 9 in iso-1-cytochrome c. Previous studies established that the biosynthesis and function of iso-1-cytochrome c is compatible with replacements at position 9 of amino acids having widely different structures (Stewart and Sherman 1972). UV-induced revertants, selected on media requiring the reversion of one or two of the amber nutritional markers, were presumed to contain a suppressor if there was the unselected reversion of at least one other marker. The 1088 suppressors that were isolated could be divided into 78 phenotypic classes. Only 43 suppressors of three classes caused the production of more than 50% of the normal amount of iso-1-cytochrome c in the cyc1-179 strain. Genetic analyses indicated that all of these highly efficient amber suppressors are allelic to one or another of the eight suppressors which cause the insertion of tyrosine at ochre (UAA) codons (Gilmore, Stewart and Sherman 1971). Furthermore, only tyrosine has been identified at position 9 in iso-1-cytochrome c in cyc1-179 strains suppressed with these efficient amber suppressors.

A deletion map of cyc1 mutants and its correspondence to mutationally altered iso-1-cytochromes c of yeast.

Mutants arising spontaneously from sporulated cultures of certain strains of yeast, Saccharomyces cerevisiae, contained deletions of the CYC1 gene which controls the primary structure of iso-1-cytochrome c. At least 60 different kinds of deletions were uncovered among the 104 deletions examined and these ranged in length from those encompassing only two adjacent point mutants to those encompassing at least the entire CYC1 gene. X-ray-induced recombination rates of crosses involving these deletions and cyc1 point mutants resulted in the assignment of 211 point mutants to 47 mutational sites and made it possible to unambiguously order 40 of these 47 sites. Except for one mutant, cyc1-15, there was a strict colinear relationship between the deletion map and the positions of 13 sites that were previously determined by amino acid alterations in iso-1-cytochromes c from intragenic revertants.

Mutants of yeast defective in iso-1-cytochrome c.

A medium containing chlorolactate has been devised to enrich for mutants that are unable to utilize lactate for growth, and therefore that may be defective in cytochrome c. Complementation tests of 6,520 chlorolactate-resistant mutants that were obtained spontaneously or induced with UV, ICR-170, or nitrosoimidazolidone resulted in the identification of 195 mutations at the cyc1 locus, which controls the primary structure of iso-1-cytochrome c. These 195 mutants, with 16 cyc1 mutants previously isolated, were examined for total cytochrome c by spectroscopic methods, growth on lactate medium, suppressibility by defined nonsense suppressors, mutational sites by x-ray-induced recombination, ability to revert, and in 86 cases, whether intragenic revertants contain altered iso-1-cytochrome c. Except for the deletion mutant cyc1-1, all of the mutants appeared to contain single-site mutations that could be assigned to at least 35 different sites within the gene. The cyc1 mutants either completely lacked iso-1-cytochrome c or contained iso-1- cytochromes c that were completely or partially nonfunctional. In spite of the fact that the cyc1 mutants obtained by the chlorolactate procedure were selected on the basis of defective function, 68% appeared to completely lack iso-1-cytochrome c. The remaining cyc1 mutants contained below normal amounts of iso-1-cytochromes c. Studies at several incubation temperatures indicated that these nonfunctional iso-1-cytochromes c were thermolabile. It is suggested that the predominant means for abolishing iso-1-cytochrome c by mutations are either through a complete loss, such as produced by chain terminating codons, or impairments through drastic changes of tertiary structure which lead to instability and thermolability.

Identification of true drug response to antidepressants. Use of pattern analysis.

The purpose of this study was to develop a method for differentiating specific ("true") and nonspecific antidepressant drug response for the individual patient. Patterns of clinical response, based on weekly global ratings of clinical status, were generated for each of 185 patients participating in six-week placebo-controlled drug trials. We hypothesized and found that substantially more patients receiving active than placebo medication displayed treatment response patterns characterized both by two-week or greater delay in onset of initial improvement and nonfluctuating persistence of improvement once achieved. Identification of a distinctive pattern of clinical response to an active drug has both research and clinical applications. Pattern analysis may contribute to understanding the nature of drug mechanisms of action, may clarify some ambiguous treatment study outcomes, and in the individual case, may facilitate clinical management.

Use of pattern analysis to identify true drug response. A replication.

In any antidepressant study, placebo response in patients assigned active drug is a troubling source of variance. There have been few attempts to identify the patients whose conditions improve as a result of true drug effect, in contrast with improvement that is a result of nonspecific effects. In a previous report we demonstrated that true drug effect seemed to be characterized by a two-week delay in onset and persistence. We described a method of pattern analysis to identify such patients. In this report, we describe the use of pattern analysis to replicate our initial findings. Data from a new sample of 150 nonmelancholic patients support the hypothesis that true drug effect is characterized by a two-week delay in onset and persistence of improvement, once achieved. There was little evidence of the onset of antidepressant effect before two weeks. The theoretical and clinical implications of this work are discussed.

Phenelzine vs placebo in 50 patients with bulimia.

To examine the efficacy of the monoamine oxidase inhibitor phenelzine sulfate in the treatment of bulimia, a double-blind, placebo-controlled trial was conducted. In 50 women who completed the trial, phenelzine was significantly superior to placebo in the reduction of binge frequency (64% vs 5%), in the fraction of patients who had ceased bingeing at the end of the trial (35% vs 4%), and in several measures of psychological state. The superiority of phenelzine over placebo was not confined to a depressed subgroup of patients. Although no patient experienced a hypertensive crisis during the study, other side effects of phenelzine were problematic and limit the usefulness of phenelzine in this population.

Treatment of bulimia with phenelzine. A double-blind, placebo-controlled study.

Twenty bulimic women of normal weight participated in a double-blind trial studying the effects of a monoamine oxidase inhibitor (MAOI). Nine women received phenelzine sulfate and 11 received placebo. Although phenelzine's side effects were a problem, the phenelzine-treated patients reported significantly fewer binges per week and had a lower Eating Attitudes Test score. Five of the nine phenelzine-treated patients ceased binging entirely and the other four reduced their binge frequency by at least 50%; none of the 11 placebo-treated patients stopped binging and only two reduced their binge frequency by 50% or more. These data demonstrate that phenelzine is significantly more effective than placebo in the treatment of bulimic women of normal weight and suggest a place for MAOIs in the treatment of bulimic patients capable of maintaining a tyramine-free diet.

Treatment outcome validation of DSM-III depressive subtypes. Clinical usefulness in outpatients with mild to moderate depression.

An algorithm for transcribing Research Diagnostic Criteria diagnoses for depressive disorders to similar categories in the DSM-III was applied to 103 depressed outpatients previously diagnosed by Research Diagnostic Criteria. All had Hamilton Depression Rating Scale scores of 18 or less. Among 64 patients completing a six-week, double-blind study comparing desipramine hydrochloride with placebo, desipramine was significantly more effective than placebo in patients with DSM-III major depression but not in those with dysthymic disorder. Among patients with major depression, a significant drug-placebo response difference was demonstrated even in those without melancholia. These findings support the clinical usefulness of the DSM-III in the treatment of depressed outpatients. Independent of DSM-III diagnosis, however, evidence of panic attacks seemed to identify patients who benefited from desipramine therapy. This suggests that the DSM-III hierarchy, which excludes consideration of panic in patients with major depression, may require revision.

Relevance of DMS-III depressive subtype and chronicity of antidepressant efficacy in atypical depression. Differential response to phenelzine, imipramine, and placebo.

One hundred ninety-four nonmelancholic depressed outpatients with features of atypical depression took part in a 6-week randomized trial of imipramine hydrochloride, phenelzine sulfate, and placebo. Their courses of illness were also rated for chronicity. Significantly more patients responded to phenelzine (71%) than to imipramine (48%), which benefited significantly more patients than placebo (26%). Both chronicity and DMS-III diagnosis predicted response on several outcome measures. For example, patients with dysthymic disorder responded better to treatment than did those with major depression, suggesting that dysthymic disorder can be treated with medication. Placebo response correlated inversely with chronicity, regardless of DMS-III diagnosis. Atypical depression and longitudinal course of illness may add to the usefulness of DMS-III depressive diagnosis as a predictor of antidepressant response.

Phenelzine and imipramine in mood reactive depressives. Further delineation of the syndrome of atypical depression.

Sixty patients who met Research Diagnostic Criteria for major, intermittent, or minor depressive disorder and had reactive mood without atypical symptoms were treated with imipramine hydrochloride, phenelzine sulfate, or a placebo. These patients, referred to as simple mood reactive depressives, were contrasted with previously published data from 180 atypical depressives. Atypical depressives had the presence of at least one vegetative atypical sign (hypersomnia, hyperphagia, leaden feeling, or rejection sensitivity) but were otherwise indistinguishable from simple mood reactive depressives. In contrast to the atypical depressives for whom phenelzine was effective and imipramine was relatively ineffective, both medications were equivalently good in simple mood reactive depressives. Since all groups did poorly when given a placebo and well when given phenelzine, the salient feature of atypical symptoms may be that they predict poor response to imipramine. Since the difference between imipramine and placebo depends on the diagnostic group, pharmacologic dissection suggests that atypical symptoms in patients with nonautonomous mood may delineate a qualitatively distinct subgroup.

Efficacy of desipramine in depressed outpatients. Response according to research diagnosis criteria diagnoses and severity of illness.

The efficacy of desipramine for mild depression was tested in a double-blind, placebo-controlled study of outpatients with scores below 19 on the Hamilton Rating Scale for Depression (HAM-D). Of 103 such patients, 23 dropped out and 16 improved during a ten-day placebo period. Among 64 patients completing the randomized portion of the study, significantly more improved with desipramine that with placebo. The Research Diagnostic Criteria (RDC) category of major depressive disorder largely accounted for the drug-placebo response difference found for the entire sample. Patients with intermittent depressive disorder improved significantly less frequently with desipramine than patients with major depressive disorder. Independent of RDC diagnosis, severity of illness correlated with outcome. Thus, patients with pretreatment HAM-D scores at or above the median demonstrated significant drug effect, while patients with lower pretreatment HAM-D scores did not.

Phenelzine v imipramine in atypical depression. A preliminary report.

Sixty patients meeting specific criteria for atypical depression completed six weeks of double-blind, randomly assigned treatment with phenelzine sulfate, imipramine hydrochloride, or placebo. The overall response rates were 67% with phenelzine, 43% with imipramine, and 29% with placebo. At week 6, phenelzine was superior to placebo on many measures, while the superiority of imipramine to placebo was confined to several variables. Phenelzine was superior to imipramine on the interpersonal sensitivity and paranoia factors of the 90-item Hopkins Symptom Checklist, with trends toward superiority on several other measures, while imipramine was not differentially superior on any measure. Atypical depressive patients with a history of spontaneous panic attacks and hysteroid dysphoric patients both showed extremely low rates of response to placebo and high rates of response to phenelzine. Conversely, those without panic or hysteroid dysphoric features responded equally to all three treatments. Responders to pheneizine also had greater platelet monoamine oxidase inhibition while receiving drug therapy than did nonresponders. Completion of the 120-patient sample will allow more detailed analyses.