Biomedical subjects

Martin Keller

Publications and source records attributed to Martin Keller.

24 records · Page 2Linked to original sources

PubMed2003

The long-term course of rapid-cycling bipolar disorder.

BACKGROUND: Rapid cycling among patients with bipolar affective disorders is important because of its implications for long-term prognosis and for the use of antidepressants. To our knowledge, no prospective study has, as yet, described the course of this phenomenon beyond 5 years. METHODS: From 345 patients with bipolar I or bipolar II disorder followed up for a mean (SD) of 13.7 (6.1) years as part of the National Institute of Mental Health Collaborative Depression Study, 89 (25.8%) were identified who, during 1 or more years of follow-up, manifested a pattern that met DSM-IV criteria for rapid cycling. These patients were compared with the remaining bipolar patients by demographics, overall affective morbidity, morbidity during specific treatment conditions, and the likelihood of suicidal behavior. Analyses assessed whether the use of tricyclic antidepressants for depressive symptoms was associated with the persistence of rapid cycling or with tendencies to switch from depressive to manic or hypomanic phases. RESULTS: The 89 patients who showed a rapid cycling pattern were significantly more likely to have had an illness onset before 17 years of age and were more likely to make serious suicide attempts. In 4 of 5 cases, rapid cycling ended within 2 years of its onset. Resolutions were not associated with decreases in tricyclic antidepressant use. Throughout follow-up, patients prone to rapid cycling experienced more depressive morbidity than other bipolar patients, particularly when lithium carbonate was being used without tricyclic antidepressants. The use of these antidepressants was not more likely in the weeks preceding shifts from depression to mania or hypomania. CONCLUSIONS: These results indicate that bipolar patients who develop a rapid cycling pattern suffer substantial depressive morbidity and are at high risk for serious suicide attempts. These findings do not implicate tricyclic antidepressants or, by inference, serotonin reuptake inhibitors in the promotion of affective instability.

Adult↗

PubMed2003

The epidemiology of major depressive episodes: results from the International Consortium of Psychiatric Epidemiology (ICPE) Surveys.

Absence of a common diagnostic interview has hampered cross-national syntheses of epidemiological evidence on major depressive episodes (MDE). Community epidemiological surveys using the World Health Organization Composite International Diagnostic Interview administered face-to-face were carried out in 10 countries in North America (Canada and the US), Latin America (Brazil, Chile, and Mexico), Europe (Czech Republic, Germany, the Netherlands, and Turkey), and Asia (Japan). The total sample size was more than 37,000. Lifetime prevalence estimates of hierarchy-free DSM-III-R/DSM-IV MDE varied widely, from 3% in Japan to 16.9% in the US, with the majority in the range of 8% to 12%. The 12-month/lifetime prevalence ratio was in the range 40% to 55%, the 30-day/12-month prevalence ratio in the range 45% to 65%, and median age of onset in the range 20 to 25 in most countries. Consistent socio-demographic correlates included being female and unmarried. Respondents in recent cohorts reported higher lifetime prevalence, but lower persistence than those in earlier cohorts. Major depressive episodes were found to be strongly co-morbid with, and temporally secondary to, anxiety disorders in all countries, with primary panic and generalized anxiety disorders the most powerful predictors of the first onset of secondary MDE. Major depressive episodes are a commonly occurring disorder that usually has a chronic-intermittent course. Effectiveness trials are needed to evaluate the impact of early detection and treatment on the course of MDE as well as to evaluate whether timely treatment of primary anxiety disorders would reduce the subsequent onset, persistence, and severity of secondary MDE.

Adolescent↗

PubMed2003

Long-term symptomatic status of bipolar I vs. bipolar II disorders.

Weekly affective symptom severity and polarity were compared in 135 bipolar I (BP I) and 71 bipolar II (BP II) patients during up to 20 yr of prospective symptomatic follow-up. The course of BP I and BP II was chronic; patients were symptomatic approximately half of all follow-up weeks (BP I 46.6% and BP II 55.8% of weeks). Most bipolar disorder research has concentrated on episodes of MDD and mania and yet minor and subsyndromal symptoms are three times more common during the long-term course. Weeks with depressive symptoms predominated over manichypomanic symptoms in both disorders (31) in BP I and BP II at 371 in a largely depressive course (depressive symptoms=59.1% of weeks vs. hypomanic=1.9% of weeks). BP I patients had more weeks of cyclingmixed polarity, hypomanic and subsyndromal hypomanic symptoms. Weekly symptom severity and polarity fluctuated frequently within the same bipolar patient, in which the longitudinal symptomatic expression of BP I and BP II is dimensional in nature involving all levels of affective symptom severity of mania and depression. Although BP I is more severe, BP II with its intensely chronic depressive features is not simply the lesser of the bipolar disorders; it is also a serious illness, more so than previously thought (for instance, as described in DSM-IV and ICP-10). It is likely that this conventional view is the reason why BP II patients were prescribed pharmacological treatments significantly less often when acutely symptomatic and during intervals between episodes. Taken together with previous research by us on the long-term structure of unipolar depression, we submit that the thrust of our work during the past decade supports classic notions of a broader affective disorder spectrum, bringing bipolarity and recurrent unipolarity closer together. However the genetic variation underlying such a putative spectrum remains to be clarified.

Adolescent↗

PubMed2002

Cultivating the uncultured.

The recent application of molecular phylogeny to environmental samples has resulted in the discovery of an abundance of unique and previously unrecognized microorganisms. The vast majority of this microbial diversity has proved refractory to cultivation. Here, we describe a universal method that provides access to this immense reservoir of untapped microbial diversity. This technique combines encapsulation of cells in gel microdroplets for massively parallel microbial cultivation under low nutrient flux conditions, followed by flow cytometry to detect microdroplets containing microcolonies. The ability to grow and study previously uncultured organisms in pure culture will enhance our understanding of microbial physiology and metabolic adaptation and will provide new sources of microbial metabolites. We show that this technology can be applied to samples from several different environments, including seawater and soil.

Bacteria↗

PubMed2002

The prospectively observed course of illness among depressed patients who commit suicide.

OBJECTIVE: These analyses were conducted to describe the course of illness among patients with major affective disorders who commit suicide. METHOD: Twenty-nine patients who entered a long-term, high-intensity follow-up study of major affective disorders and who later committed suicide within 1 year of their last follow-up interview were individually matched to other patients by age, sex, the presence or absence of lifetime drug or alcohol abuse, time to last interview and polarity. Those who suicided were compared with their controls by depressive and substance abuse morbidity during follow-up, treatment resistance, treatment compliance, suicidal behavior and psychosocial adjustment. RESULTS: Among the various measures used to characterize the course of illness during a mean follow-up of 4.3 years, only those pertaining to suicidal behavior robustly separated the suicide group from their controls. Suicidal behavior in the remote past seemed as predictively important as suicidal behavior during follow-up. CONCLUSION: Of the various features monitored over time in patients with major affective disorder, suicidal behavior itself was the clearest correlate of risk for completed suicide.

Adult↗

PubMedDate not supplied

Global proteome discovery using an online three-dimensional LC-MS/MS.

We have developed a proteomics technology featuring on-line three-dimensional liquid chromatography coupled to tandem mass spectrometry (3D LC-MS/MS). Using 3D LC-MS/MS, the yeast-soluble, urea-solubilized peripheral membrane and SDS-solubilized membrane protein samples collectively yielded 3019 unique yeast protein identifications with an average of 5.5 peptides per protein from the 6300-gene Saccharomyces Genome Database searched with SEQUEST. A single run of the urea-solubilized sample yielded 2255 unique protein identifications, suggesting high peak capacity and resolving power of 3D LC-MS/MS. After precipitation of SDS from the digested membrane protein sample, 3D LC-MS/MS allowed the analysis of membrane proteins. Among 1221 proteins containing two or more predicted transmembrane domains, 495 such proteins were identified. The improved yeast proteome data allowed the mapping of many metabolic pathways and functional categories. The 3D LC-MS/MS technology provides a suitable tool for global proteome discovery.

Amino Acid Sequence↗