Depression among Asian-American Adults in the Community: Systematic Review and Meta-Analysis

Objectives

In this systematic review, we provide an overview of the literature on depression among Asian-Americans and explore the possible variations in depression prevalence estimates by methodological and demographic factors.

Methods

Six databases were used to identify studies reporting a prevalence estimate for depression in Asian-American adults in non-clinical settings. Meta-analysis was used to calculate pooled estimates of rates of depression by assessment type. Statistical heterogeneity was assessed for subgroup analyses by gender, age, ethnicity, and other participant characteristics.

Results

A total of 58 studies met the review criteria (n = 21.731 Asian-American adults). Heterogeneity across the studies was considerably high. The prevalence of major depression assessed via standardized clinical interviews ranged between 4.5% and 11.3%. Meta-analyses revealed comparable estimated prevalence rates of depression as measured by the Center for Epidemiologic Studies Depression Scale (35.6%, 95% CI 27.6%–43.7%) and the Geriatric Depression Scale (33.1%, 95% CI 14.9%–51.3%). Estimates varied by Asian racial/ethnic group and other participant characteristics. Estimates of depression among special populations, which included maternity, caregivers, and homosexuals, were significantly higher than estimates obtained from other samples (58.8% vs 29.3%, p = .003). Estimates of depression among Korean and Filipino-Americans were similar (33.3%-34.4%); however, the estimates were twice as high as those for Chinese-Americans (15.7%; p = .012 for Korean, p = .049 for Filipino).

Conclusion

There appears to be wide variability in the prevalence rates of depression among Asian-Americans in the US. Practitioners and researchers who serve Asian-American adults need to be sensitive to the potential diversity of the expression of depression and treatment-seeking across Asian-American subgroups. Public health policies to increase Asian-American access to mental health care, including increased screening, are necessary. Further work is needed to determine whether strategies to reduce depression among specific Asian racial/ethnic groups is warranted.     

Sufflavibacter maritimus gen. nov., sp. nov., novel Flavobacteriaceae bacteria isolated from marine environments

Four Gram-negative, chemoheterotrophic, nonmotile, yellow-colored strains were isolated from the East Sea or from deep-sea sediments of Nankai Trough by standard dilution plating. Characterization by polyphasic approaches indicated that the four strains are members of the same species. Phylogenetic analyses based on 16S rRNA gene sequences revealed that the strains formed a coherent and novel genus-level lineage within the family Flavobacteriaceae. The dominant cellular fatty acids were i-C15:0, 3-OH i-C17:0, and 2-OH i-C15:0 and/or C16:1 omega7c. Predominance of 2-OH i-C 15:0 and/or C16:1omega7c clearly differentiated the strains from closely related members. The DNA G+C contents ranged 35.1-36.2 mol%. It is proposed, from the polyphasic evidence, that the strains should be placed into a novel genus and species named Sufflavibacter maritimus gen. nov., sp. nov., with strain IMCC 1001T (=KCCM 42359T=NBRC 102039T) as the type strain.     

Improved Thermostability and Acetic Acid Tolerance of Escherichia coli via Directed Evolution of Homoserine o-Succinyltransferase

In Escherichia coli, growth is limited at elevated temperatures mainly because of the instability of a single enzyme, homoserine o-succinyltransferase (MetA), the first enzyme in the methionine biosynthesis pathway. The metA gene from the thermophile Geobacillus kaustophilus cloned into the E. coli chromosome was found to enhance the growth of the host strain at elevated temperature (44°C), thus confirming the limited growth of E. coli due to MetA instability. In order to improve E. coli growth at higher temperatures, we used random mutagenesis to obtain a thermostable MetA_{E. coli} protein. Sequencing of the thermotolerant mutant showed five amino acid substitutions: S61T, E213V, I229T, N267D, and N271K. An E. coli strain with the mutated metA gene chromosomally inserted showed accelerated growth over a temperature range of 34 to 44°C. We used the site-directed metA mutants to identify two amino acid residues responsible for the sensitivity of MetA_{E. coli} to both heat and acids. Replacement of isoleucine 229 with threonine and asparagine 267 with aspartic acid stabilized the protein. The thermostable MetA_{E. coli} enzymes showed less aggregation in vivo at higher temperature, as well as upon acetic acid treatment. The data presented here are the first to show improved E. coli growth at higher temperatures solely due to MetA stabilization and provide new knowledge for designing E. coli strains that grow at higher temperatures, thus reducing the cooling cost of bioprocesses.     

Two different methods of evaluating nutrient limitations of periphyton bioassays,using water from the River Rhine and eight of its tributaries

An investigation was untertaken to evaluate the nutrient status of the River Rhine (two stations) and eight of its tributaries (total of ten samplings). Determinations of the following inorganic substances were made: PO₄ ^?3-P; NO₃ ^?-N; NO₂ ^?-N; NH₄ ⁺ -N and Cl^?. In addition, pH and carbonate alkalinity were measured. Bioassays to obtain the algal growth potential (AGP) were carried out using periphyton from the River Rhine. A linear relationship could be established between NO₃ ^?-N and the AGP, while the AGP showed a non-linear dependence on the PO₄ ^3?-P concentration. The critical N/P ratio for N or P limitation of the algal growth in bioassays was evaluated graphically and by calculation. The results of the two methods are in good agreement: N is the limiting factor at NO₃ ^?N/PO₄ ^3?-P ratios less than 10, while P is limiting at ratios greater than 20. At values between 10 and 20 neither N nor P can be supposed with certainty to be limiting.     

Aminolysis of oxalate esters in toluene: A model for a carboxylate buried in a hydrophobic environment at an active site

We have examined the aminolysis of the mono-o-nitrophenyl ester of oxalic acid by piperidine in toluene with the purpose of determining how a carboxylate “buried” at an active site might affect an enzyme-catalyzed reaction. The oxalate ester and piperidine form an ion pair (R₂NH₂⁺⁻O₂CCO₂Ar) even in extremely dilute toluene solutions. This conclusion is supported by the kinetic effects of acidic and basic additives and by a “concentration inversion” experiment. The oxalate ester was found to react more than three orders of magnitude faster than o-nitrophenyl acetate. The neighboring carboxylate in the ion pair apparently accelerates the decomposition of a tetrahedral intermediate by accepting a proton from the amine nitrogen. The implications of this anchimeric assistance to enzymatic systems is discussed briefly.