A Simple in situ Assay to Assess Plant-Associative Bacterial Nitrogenase Activity

Assessment of plant-associative bacterial nitrogen (N) fixation is crucial for selection and development of elite diazotrophic inoculants that could be used to supply cereal crops with nitrogen in a sustainable manner. Although diazotrophic bacteria possess diverse oxygen tolerance mechanisms, most require a sub 21% oxygen environment to achieve optimal stability and function of the N-fixing catalyst nitrogenase. Consequently, assessment of N fixation is routinely carried out on “free-living” bacteria grown in the absence of a host plant and such experiments may not accurately divulge activity in the rhizosphere where the availability and forms of nutrients such as carbon and N, which are key regulators of N fixation, may vary widely. Here, we present a modified in situ acetylene reduction assay (ARA), utilizing the model cereal barley as a host to comparatively assess nitrogenase activity in diazotrophic bacteria. The assay is rapid, highly reproducible, applicable to a broad range of diazotrophs, and can be performed with simple equipment commonly found in most laboratories that investigate plant-microbe interactions. Thus, the assay could serve as a first point of order for high-throughput identification of elite plant-associative diazotrophs

Circadian hormone secretory profiles in women with severe premenstrual tension syndrome.

The circadian secretory profiles of serum prolactin, growth hormone and cortisol were measured in two women suffering from severe premenstrual tension syndrome and in two asymptomatic control subjects. Subjects and controls were screened and included after a rigorous selection process. Blood samples were obtained every 30 min over a period of 24 h in each woman both on day 9 (follicular phase) and day 26 (luteal phase) of the menstrual cycle. There was no relationship between the hormonal secretory profiles and the premenstrual tension syndrome.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75119/1/j.1471-0528.1984.tb04785.x.pd

Diagnosis of endogenous depression : Comparison of clinical, research and neuroendocrine criteria

Eighty-nine depressed outpatients were studied by clinical criteria, Research Diagnostic Criteria (RDC), and the dexamethasone suppression test (DST) of neuroendocrine regulation. A simple outpatient version of the DST, requiring only one blood sample, correctly identified 40% of patients diagnosed clinically as endogenous depression (ED), with a specificity of 98% and a diagnostic confidence of 95%. Differences in age, sex, or severity of symptoms between endogenous and non-endogenous depressives did not account for these results. By comparison, the diagnostic performance of the DST was weaker for the RDC categories Major Depressive Disorder (MDD) and primary MDD. These were less selective and more heterogenous than the clinical category ED. The clinical diagnoses of ED were supported in 98% of cases by the RDC, but 22% of RDC endogenous MDD diagnoses were not supported by the clinical diagnoses. Abnormal DST results were found only in patients with both the clinical diagnosis of ED and the RDC diagnosis of endogenous MDD. Patients with definite endogenous MDD had a significantly higher frequency of abnormal DST results (42%) than those with probable endogenous MDD (14%), or those with other RDC diagnoses (3%). A significant association was found between positive DST results and a positive family history of depression. These results support other evidence for use of a positive DST result as an external validating criterion for ED. The category MDD contained all cases diagnosed clinically as ED, but was diluted by cases diagnosed clinically as non-endogenous depression who had no neuroendocrine disturbance. The results also confirmed that the endogenous/nonendogenous and primary/secondary classifications of depression are not identical.We conclude: (1) that the DST can be used in the differential diagnosis of depressed outpatients as well as inpatients; (2) that the RDC category primary MDD and the Washington University category primary depression are more heterogenous and probably less valid than the clinical category ED; (3) that the RDC for endogenous MDD have only moderate validity; (4) that RDC diagnoses cannot substitute for careful clinical diagnoses in research studies, (5) that the best use of the RDC is to support clinical diagnoses, but not to generate diagnoses independently as a free-standing system; (6) that the concept of endogenous or endogenomorphic depression has validity and should be retained in research studies of depression.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23153/1/0000078.pd

Biologic validation of diagnoses of depression

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24517/1/0000796.pd

A randomized single blind crossover trial comparing leather and commercial wrist splints for treating chronic wrist pain in adults

<p>Abstract</p> <p>Background</p> <p>To compare the effectiveness of a custom-made leather wrist splint (LS) with a commercially available fabric splint (FS) in adults with chronic wrist pain.</p> <p>Methods</p> <p>Participants (N = 25, mean age = 54) were randomly assigned to treatment order in a 2-phase crossover trial. Splints were worn for 2 weeks, separated by a one-week washout period. Outcomes were assessed at baseline and after each splint phase using the Australian/Canadian Osteoarthritis Hand Index (AUSCAN), the Canadian Occupational Performance Measure (COPM) and Jamar dynamometer by an observer blinded to treatment allocation.</p> <p>Results</p> <p>Both styles of wrist splint significantly reduced pain (effect size LS 0.79, FS 0.43), improved hand function and increased grip strength compared to baseline (all p < 0.05) with no increase in wrist stiffness. There was a consistent trend for the LS to be superior to the FS but this was statistically significant only for patient perceived occupational performance (p = 0.008) and satisfaction (p = 0.015). Lastly, 72% of patients preferred the custom-made leather splint compared to the commercially available splint.</p> <p>Conclusion</p> <p>Leather wrist splints were superior to a commercially available fabric splint for the short-term relief of pain and dysfunction.</p

Sequential induction of three recombination directionality factors directs assembly of tripartite integrative and conjugative elements

Tripartite integrative and conjugative elements (ICE3) are a novel form of ICE that exist as three separate DNA regions integrated within the genomes of Mesorhizobium spp. Prior to conjugative transfer the three ICE3 regions of M. ciceri WSM1271 ICEMcSym1271 combine and excise to form a single circular element. This assembly requires three coordinated recombination events involving three site-specific recombinases IntS, IntG and IntM. Here, we demonstrate that three excisionases–or recombination directionality factors—RdfS, RdfG and RdfM are required for ICE3 excision. Transcriptome sequencing revealed that expression of ICE3 transfer and conjugation genes was induced by quorum sensing. Quorum sensing activated expression of rdfS, and in turn RdfS stimulated transcription of both rdfG and rdfM. Therefore, RdfS acts as a “master controller” of ICE3 assembly and excision. The dependence of all three excisive reactions on RdfS ensures that ICE3 excision occurs via a stepwise sequence of recombination events that avoids splitting the chromosome into a non-viable configuration. These discoveries expose a surprisingly simple control system guiding molecular assembly of these novel and complex mobile genetic elements and highlight the diverse and critical functions of excisionase proteins in control of horizontal gene transfer

Neuroendocrine dysfunction in genetic subtypes of primary unipolar depression

Disinhibited activity of the hypothalamic-pituitary-adrenocortical (HPA) neuroendocrine system, characterized most specifically by abnormal responses to the dexamethasone suppression test (DST), is observed in 40-50% of patients with endogenous depression. The heterogeneity of endogenous depressives with respect to this neuroendocrine marker is so far unexplained. A recent report from Iowa suggested that genetic factors could account for this heterogeneity, since abnormal DST responses were found with widely differing frequencies among primary unipolar depressives subtyped by the genetic criteria of Winokur. We studied 14 patients with primary endogenous delusional unipolar depression. Abnormal DST responses were found in 79% of the entire group, and with similar frequencies among each of the Winokur subtypes. In particular, five of six patients (83%) with depression spectrum disease had abnormal DST results. This contrasts with a frequency of 4% reported by the Iowa group. We conclude that disinhibited HPA activity does occur in depression spectrum disease when a delusional endogenous depression is present. Our results and those of the Iowa study could both be consistent with a threshold model of HPA activation. The high frequency of positive DST results in delusional endogenous depressives may be determined by disinhibited central pain mechanisms. Variations in this clinical dimension, combined with variations in threshold for HPA activation by pain mechanisms, could account for the heterogeneity of DST responses among endogenous depressives.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23209/1/0000138.pd

Monitoring of antidepressant response to ECT with polysomnographic recordings and the dexamethasone suppression test

Ten patients treated with electroconvulsive therapy (ECT) only were followed with serial sleep polysomnographic recordings and dexamethasone suppression tests (DSTs). Both biological correlates of depression showed improvement with ECT. The use of serial sleep measures and serial DSTs in monitoring the clinical response to ECT is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27310/1/0000331.pd

Premenstrual tension syndrome: The development of research diagnostic criteria and new rating scales

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66428/1/j.1600-0447.1980.tb00605.x.pd