Outpatient Theophylline Determinations

The indications and usefulness of outpatient serum theophylline determinations were prospectively evaluated by doing 151 of these studies in 137 consecutive cases of chronic obstructive pulmonary disease. We found that evaluations were done for the following three groups of indications: group A, worsening bronchospasm; group B, stable asymptomatic cases, and group C, symptoms suggesting theophylline toxicity. When the three clinical groups were compared for frequency of nontherapeutic values, only an increased frequency of subtherapeutic values in patients with bronchospasm (group A) was significant (P<.01). Increasing the dosage up to 15 mg per kg of body weight a day while theophylline determinations are pending appears to be safe in this group of patients. Toxic symptoms were rarely associated with concentrations greater than 20 μg per ml (3/13) and infrequently occurred in patients with concentrations greater than 20 μg per ml (3/29). Nontherapeutic theophylline values did not always result in an adjustment of theophylline dosage. This was influenced by a correlation of symptoms, timing of the theophylline determination and the use of other bronchodilators.     

Lifetime stability of ADHD symptoms in older adults

Attention-deficit/hyperactivity disorder (ADHD) has been shown to continue into old age. Studies in children and younger adults show a reduction in hyperactive-impulsive symptoms, whereas the number of inattentive symptoms stays stable. The current study examined the lifetime stability of ADHD symptoms up to old age. Data on ADHD diagnosis and symptoms were collected in a two-phase side-study (N = 231) of the Longitudinal Aging Study Amsterdam. Paired t tests and ANCOVAs were used to analyze the data. Paired t test suggests continuity of the number of reported ADHD symptoms currently present and present in childhood. The change in the balance of inattentive/hyperactive-impulsive symptoms at present and in childhood is also the same in persons with ADHD. Finally, the difference in the change in the balance of inattentive/hyperactive-impulsive symptoms in those with and without ADHD suggests continuity throughout the life span. Our results suggest that diagnostic criteria developed for younger adults may be used among older adults. However, we collected our data retrospectively, which may have biased our results. Future research should follow larger cohorts of patients with ADHD prospectively over the life span.     

Homocysteine and familial longevity: the Leiden Longevity Study

Homocysteine concentrations are a read-out of methionine metabolism and have been related to changes in lifespan in animal models. In humans, high homocysteine concentrations are an important predictor of age related disease. We aimed to explore the association of homocysteine with familial longevity by testing whether homocysteine is lower in individuals that are genetically enriched for longevity. We measured concentrations of total homocysteine in 1907 subjects from the Leiden Longevity Study consisting of 1309 offspring of nonagenarian siblings, who are enriched with familial factors promoting longevity, and 598 partners thereof as population controls. We found that homocysteine was related to age, creatinine, folate, vitamin B levels and medical history of hypertension and stroke in both groups (all p<0.001). However, levels of homocysteine did not differ between offspring enriched for longevity and their partners, and no differences in the age-related rise in homocysteine levels were found between groups (p for interaction 0.63). The results suggest that homocysteine metabolism is not likely to predict familial longevity.     

Honeybee (Apis cerana) guards do not discriminate between robbers and reproductive parasites

A hopelessly queenless honeybee colony has only one reproductive option: some workers must produce sons before the colony dies. This requires the workers to curtail egg policing (removal of worker-produced eggs), rendering the colony vulnerable to non-natal reproductive parasitism. In the Western honeybee, Apis mellifera, guarding (prevention of foreign workers from entering a colony) increases in queenless colonies, providing a defence against non-natal parasitism. However, in the closely related Eastern honeybee A. cerana, queenless colonies appear to be more tolerant of bees from other colonies. We presented guards of four A. cerana colonies with three types of workers: nestmate returning foragers, non-nestmate returning foragers and non-nestmates from a laying-worker colony. The latter are likely to have active ovaries, allowing us to test whether guard bees can detect which potential invaders are more likely to be reproductive parasites. After assessing guards’ reactions, we recaptured test bees and dissected them to determine levels of ovary activation. We found that nestmates were accepted significantly more frequently than the other two types of workers. However, there was no difference in the overall acceptance rates of non-nestmate returning foragers and bees from within laying-worker colonies. In addition, ovary-activated workers were no less likely to be accepted than those with inactive ovaries. Interestingly, colonies were more accepting of all three types of test bee after being made queenless. We conclude that, as has been previously suggested, guarding has no specific role in the prevention of non-natal parasitism in A. cerana.     

Modulation of the Maladaptive Stress Response to Manage Diseases of Protein Folding

Diseases of protein folding arise because of the inability of an altered peptide sequence to properly engage protein homeostasis components that direct protein folding and function. To identify global principles of misfolding disease pathology we examined the impact of the local folding environment in alpha-1-antitrypsin deficiency (AATD), Niemann-Pick type C1 disease (NPC1), Alzheimer''s disease (AD), and cystic fibrosis (CF). Using distinct models, including patient-derived cell lines and primary epithelium, mouse brain tissue, and Caenorhabditis elegans, we found that chronic expression of misfolded proteins not only triggers the sustained activation of the heat shock response (HSR) pathway, but that this sustained activation is maladaptive. In diseased cells, maladaptation alters protein structure–function relationships, impacts protein folding in the cytosol, and further exacerbates the disease state. We show that down-regulation of this maladaptive stress response (MSR), through silencing of HSF1, the master regulator of the HSR, restores cellular protein folding and improves the disease phenotype. We propose that restoration of a more physiological proteostatic environment will strongly impact the management and progression of loss-of-function and gain-of-toxic-function phenotypes common in human disease.     

Heritability of worker ovariole number in the Cape honey bee <Emphasis Type="Italic">Apis mellifera capensis</Emphasis>

In the honey bee (Apis mellifera), a key feature of the queen/worker caste dimorphism is a dramatic difference in ovariole number. However, even within the worker caste, variation in ovariole number is associated with the variance in reproductive potential. Workers of the Cape honey bee, A. m. capensis, are unique in that they are able to produce diploid female offspring asexually, and as a result, have a highly reproductive phenotype, a central feature of which is high ovariole number. We show that patrilines (subfamilies of full-sister workers sharing a father) within colonies vary significantly in ovariole number. Heritability of ovariole number was significantly greater than zero in two population samples (1991–1992: h ² = 0.19 ± 0.11; 1992–1993: h ² = 0.57 ± 0.19), suggesting a significant additive genetic as well as an environmental contribution to this trait. During the course of this study, we indirectly observed the replacement (supersedure) of a queen by her worker-produced granddaughter, providing confirmation of the reproductive potential of A. m. capensis workers.     

A thelytokous lineage of socially parasitic honey bees has retained heterozygosity despite at least 10 years of inbreeding

The honey bee population of South Africa is divided into two subspecies: a northern population in which queenless workers reproduce arrhenotokously and a southern one in which workers reproduce thelytokously. A hybrid zone separates the two, but on at least three occasions the northern population has become infested by reproductive workers derived from the southern population. These parasitic workers lay in host colonies parthenogenetically, resulting in yet more parasites. The current infestation is 20-year old--surprising because an asexual lineage is expected to show a decline in vigor over time due to increasing homozygosity. The decline is expected to be acute in honey bees, where homozygosity at the sex locus is lethal. We surveyed colonies from the zone of infestation and genotyped putative parasites at two sets of linked microsatellite loci. We confirm that there is a single clonal lineage of parasites that shows minor variations arising from recombination events. The lineage shows high levels of heterozygosity, which may be maintained by selection against homozygotes, or by a reduction in recombination frequency within the lineage. We suggest that the clonal lineage can endure the costs of asexual reproduction because of the fitness benefits of its parasitic life history.     

A protein complex network of Drosophila melanogaster

Determining the composition of protein complexes is an essential step toward understanding the cell as an integrated system. Using coaffinity purification coupled to mass spectrometry analysis, we examined protein associations involving nearly 5,000 individual, FLAG-HA epitope-tagged Drosophila proteins. Stringent analysis of these data, based on a statistical framework designed to define individual protein-protein interactions, led to the generation of a Drosophila protein interaction map (DPiM) encompassing 556 protein complexes. The high quality of the DPiM and its usefulness as a paradigm for metazoan proteomes are apparent from the recovery of many known complexes, significant enrichment for shared functional attributes, and validation in human cells. The DPiM defines potential novel members for several important protein complexes and assigns functional links to 586 protein-coding genes lacking previous experimental annotation. The DPiM represents, to our knowledge, the largest metazoan protein complex map and provides a valuable resource for analysis of protein complex evolution.