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Biomedical subjects

D Solomon

Publications and source records attributed to D Solomon.

At least 19 recordsLinked to original sources
PubMed2006

The association between course of illness and subsequent morbidity in bipolar I disorder.

OBJECTIVE: We examined the relationship between certain bipolar I disorder clinical course variables over 5 years with outcome over the subsequent 5-year period. METHODS: Prospective observational follow-up data of 123 bipolar I subjects were analyzed. Predictive clinical variables included the frequency and direction of switches, and the quantity, polarity and length of affective periods. Outcome variables were an affective burden index (ABI) accounting for week-by-week severity and weeks hospitalized. Bivariate analyses guided the selection of predictors for multivariable analyses against the outcome variables. RESULTS: Affective burden index: while the number and direction of switches, the number of polyphasic episodes, weeks in hypomania/mania/mixed state, weeks in minor/major depression, weeks in at least marked affective syndrome, and weeks in any affective syndrome all had bivariate correlation (p<0.01) with the ABI, only weeks in hypomania/mania/mixed state and weeks in minor/major depression made significant contributions in the multivariable analysis (p<0.01) with the ABI. Weeks hospitalized: weeks in at least marked affective syndrome were significantly correlated with weeks hospitalized in bivariate analysis (p<0.01), and maintained a contribution to weeks hospitalized in the multivariable analysis (p<0.01). CONCLUSIONS: The quantity and severity of weeks in symptomatic affective states are possibly greater predictors of affective burden in bipolar I patients than the quantity and direction of affective switches.

Adult↗
PubMed2003

Torsional and horizontal vestibular ocular reflex adaptation: three-dimensional eye movement analysis.

This study used visual-vestibular conflict to effect short-term torsional and horizontal adaptation of the vestibulo-ocular reflex (VOR). Seven normal subjects underwent sinusoidal whole-body rotation about the earth-vertical axis for 40 min (+/- 37 degrees/s, 0.3 Hz) while viewing a stationary radial pattern fixed to the chair (x0 viewing). During adaptation and testing in darkness, the head was pitched either up or down 35 degrees to excite both the horizontal and torsional VOR. The eyes were kept close to zero orbital elevation. Eye movements were recorded with a dual search coil in a three-field magnetic system. VOR gain was determined by averaging peak eye velocity from ten cycles of chair oscillation in complete darkness. The gain of the angular horizontal VOR (response to rotation about the head rostral-caudal axis) was significantly reduced after training in both head orientations. Angular torsional VOR gain (head rotation about the naso-occipital axis) was reduced in both head orientations, but this reached statistical significance only in the head down position. These results suggest that torsional and horizontal VOR gain adaptation, even when elicited together, may be subject to different influences depending upon head orientation. Differences between head up and down could be due to the relatively greater contribution of the horizontal semicircular canals with nose-down pitch. Alternatively, different VOR-adaptation processes could depend on the usual association of the head down posture to near viewing, in which case the torsional VOR is relatively suppressed.

Adaptation, Physiological↗
PubMed2003

Supranuclear gaze palsy and opsoclonus after Diazinon poisoning.

A 52 year old man developed a supranuclear gaze palsy and opsoclonus after Diazinon poisoning. The diagnosis was confirmed by low plasma and red blood cell cholinesterase activity and urine mass spectroscopy. Saccadic control may be mediated in part by acetylcholine. Opsoclonus in the setting of organophosphate intoxication may occur as a result of cholinergic excess which overactivates the fastigial nuclei.

Diazinon↗
PubMed2001

A synthetic pentasaccharide with GTPase activity.

The design, synthesis, and preliminary evaluation of the first example of synthetic pentasaccharide (1) that shows marked rate enhancement and specificity for the hydrolysis of GTP to GDP and orthophosphate (OP) are reported. At the concentration ratios of GTP/1 = 3.6 and GTP/Mg(2+) = 1 (pH 7.1, 50 degrees C), a rate enhancement of about 500-fold was obtained.[reaction: see text]

Carbohydrate Conformation↗
PubMed2001

Stereochemistry of family 52 glycosyl hydrolases: a beta-xylosidase from Bacillus stearothermophilus T-6 is a retaining enzyme.

A beta-xylosidase from Bacillus stearothermophilus T-6 assigned to the uncharacterized glycosyl hydrolase family 52 was cloned, overexpressed in Escherichia coli and purified. The enzyme showed maximum activity at 65 degrees C and pH 5.6-6.3. The stereochemistry of the hydrolysis of p-nitrophenyl beta-D-xylopyranoside was followed by 1H-nuclear magnetic resonance. Time dependent spectrum analysis showed that the configuration of the anomeric carbon was retained, indicating that a retaining mechanism prevails in family 52 glycosyl hydrolases. Sequence alignment and site-directed mutagenesis enabled the identification of functionally important amino acid residues of which Glu337 and Glu413 are likely to be the two key catalytic residues involved in enzyme catalysis.

Catalysis↗
PubMed2001

Comparison of three management strategies for patients with atypical squamous cells of undetermined significance: baseline results from a randomized trial.

BACKGROUND: More than 2 million U.S. women receive an equivocal cervical cytologic diagnosis (atypical squamous cells of undetermined significance [ASCUS]) each year. Effective colposcopy triage strategies are needed to identify the minority of women who have clinically significant disease while avoiding excessive follow-up evaluation for others. METHODS: The ASCUS/LSIL (i.e., low-grade squamous intraepithelial lesion) Triage Study (ALTS) is a multicenter, randomized trial comparing the sensitivity and specificity of the following three management strategies to detect cervical intraepithelial neoplasia grade 3 (CIN3): 1) immediate colposcopy (considered to be the reference standard), 2) triage to colposcopy based on human papillomavirus (HPV) results from Hybrid Capture 2(TM) (HC 2) and thin-layer cytology results, or 3) triage based on cytology results alone. This article summarizes the cross-sectional enrollment results for 3488 women with a referral diagnosis of ASCUS. All statistical tests are two-sided. RESULTS: Among participants with ASCUS, the underlying prevalence of histologically confirmed CIN3 was 5.1%. Sensitivity to detect CIN3 or above by testing for cancer-associated HPV DNA was 96.3% (95% confidence interval [CI] = 91.6% to 98.8%), with 56.1% of women referred to colposcopy. Sensitivity of a single repeat cytology specimen with a triage threshold of HSIL or above was 44.1% (95% CI = 35.6% to 52.9%), with 6.9% referred. Sensitivity of a lower cytology triage threshold of ASCUS or above was 85.3% (95% CI = 78.2% to 90.8%), with 58.6% referred. CONCLUSIONS: HC 2 testing for cancer-associated HPV DNA is a viable option in the management of women with ASCUS. It has greater sensitivity to detect CIN3 or above and specificity comparable to a single additional cytologic test indicating ASCUS or above.

Adult↗
PubMed2001

Lithium and suicidal behavior in major affective disorder: a case-control study.

OBJECTIVE: A number of studies have suggested that lithium may be particularly effective in reducing suicide risks among patients with major affective disorders. The design of many of these studies left them open to biases associated with treatment compliance, however. METHOD: Subjects were drawn from a naturalistic, long-term follow-up of patients with major affective disorders. Fifteen who committed suicide while receiving somatotherapy where matched to non-suicidal patients who were similarly receiving somatotherapy at the same point in follow-up. The same procedure was followed for 41 patients who made a serious suicide attempt during follow-up. RESULTS: Six (40.0%) of the patients who committed suicide, and eight (53.3%) of their controls, were thought to have been taking lithium in the preceding week. Among attempters and their controls, nine (22.0%) and eight (19.5%), respectively, were taking lithium. CONCLUSION: These results do not support previous suggestions that lithium has uniquely antisuicidal properties. Other existing datasets should be explored with this design to establish whether lithium does, or does not, offer special protection against suicide.

Adult↗
PubMed2001

Growth factor control of CNS myelination.

The molecular signals required for initiating myelination and maintenance of the myelin internode are not known. Several growth factor families have been implicated in promoting oligodendrocyte survival or differentiation and may have consequences on formation of myelin. We developed a reliable assay for detecting ensheathment of neurites by oligodendrocytes in spinal cord explants. This system was used to assay the effect of selected growth factors on myelin internode formation. We examined the influence on myelination of the polypeptide growth factors neuregulin (NRG), platelet-derived growth factor (PDGF), leukemia inhibitory factor (LIF), and the thyroid hormone T(3). We found that NRG, PDGF, and T(3) treatments enhanced myelination while LIF treatment inhibited it. We furthermore found that the most potent combination of factors to enhance myelination was NRG and T(3). Our results demonstrate that the role of growth factors on CNS myelination can be reliably studied in a controlled in vitro environment and that the impact of individual or combinations of growth factors on myelination cannot be predicted by their known effects on oligodendrocyte survival, proliferation, or differentiation.

Animals↗
PubMed2001

Qualification of ASCUS. A comparison of equivocal LSIL and equivocal HSIL cervical cytology in the ASCUS LSIL Triage Study.

Cytologic detection of high-grade squamous intraepithelial lesions (HSILs) is critical to cervical cancer prevention. Therefore, identifying "equivocal HSIL" (ASCUS [atypical squamous cells of undetermined significance]-H) may be useful. Accordingly, we compared findings associated with "equivocal low-grade SIL" (ASCUS-L), ASCUS-H, and HSIL using data from the ASCUS LSIL (low-grade squamous intraepithelial lesion) Triage Study. The frequency of oncogenic human papillomavirus (HPV) DNA detection and underlying lesions cervical intraepithelial neoplasia (CIN) 2 or worse or CIN 3 or worse in women with ASCUS-H was intermediate between that of ASCUS-L and HSIL. Oncogenic HPV DNA was associated with 85.6% of ASCUS-H ThinPreps and 69.8% of ASCUS-H smears. Histopathologic lesions CIN 2 or worse were associated with 40.5% of ASCUS-H ThinPreps and 27.2% of ASCUS-H smears (mostly CIN 3). Nevertheless, numerically more lesions CIN 2 or worse were preceded by ASCUS-L than by ASCUS-H because ASCUS-L was more common. ASCUS-H is an uncommon interpretation that derives clinical usefulness from its high positive predictive value for lesions CIN 2 or worse.

Clinical Laboratory Techniques↗
PubMed2001

GALEN ten years on: tasks and supporting tools.

The GALEN technology has matured over more than a decade of use. We describe a set of software tools and associated methodologies that together are supporting ontological engineering in a production, rather than a research setting.

Artificial Intelligence↗
PubMed2000

Epidermal growth factor receptor transcriptionally up-regulates vascular endothelial growth factor expression in human glioblastoma cells via a pathway involving phosphatidylinositol 3'-kinase and distinct from that induced by hypoxia.

Glioblastomas are highly vascular malignant brain tumors that often overexpress vascular endothelial growth factor (VEGF). They also frequently overexpress epidermal growth factor receptor (EGFR) and contain regions of hypoxia, both conditions that can induce VEGF. We examined VEGF regulation in U87 MG human glioblastoma cells and in U87/T691 cells, a clonal derivative that contains a truncated erbB2/Neu receptor that interferes with EGFR signaling through the formation of nonfunctional heterodimeric receptor complexes. U87/T691 cells contained approximately one-half as much VEGF mRNA as did U87 MG cells under normoxic conditions (21% oxygen). Pharmacological inhibition of EGFR, Ras, or PI(3) kinase, but not MAP kinase, led to a significant decrease in VEGF mRNA levels in U87 MG cells. VEGF promoter activity in transient transfections was decreased by either pharmacological or genetic inhibition of EGFR, Ras, or phosphatidylinositol 3'-kinase [PI(3) kinase]. However, inhibition of PI(3) kinase or EGFR did not completely abolish induction of VEGF mRNA by hypoxia (0.2% oxygen). Likewise, VEGF mRNA expression was induced 3-fold by hypoxia in EGFR-inhibited U87/T691 cells, comparable with the fold induction seen in parental U87 MG cells, although the absolute level of message under hypoxia was higher in U87 MG cells. In transient transfections, a luciferase reporter construct containing a 1.2-kb fragment of the VEGF promoter, lacking the known hypoxic-responsive element (HRE), showed up-regulation after EGF stimulation to the same degree as the full-length, 1.5-kb VEGF promoter construct retaining the HRE. Furthermore, activity of the HRE-deleted, 1.2-kb promoter luciferase reporter was down-regulated by PI(3) kinase inhibition. Therefore, in glioblastoma cells, transcriptional regulation of the VEGF promoter by EGFR appears to involve Ras/PI(3) kinase and to be distinct from signals induced by hypoxia.

Cell Hypoxia↗
PubMed2000

Family history and symptom levels during treatment for bipolar I affective disorder.

BACKGROUND: Studies of family history and lithium response in patients with bipolar affective disorder have produced mixed results, but the majority have shown relationships between the presence of affective disorder among relatives and positive responses to lithium in probands. The analysis presented here sought to confirm and to further characterize such relationships. METHODS: Subjects described here participated in a long-term, prospective follow-up; had a history of Research Diagnostic Criteria manic disorder or schizoaffective disorder, manic type; and took lithium for periods of 26 weeks or longer. The majority participated in a family study in which first-degree relatives were directly interviewed. Morbidity during lithium and during anticonvulsant trials was quantified in alternative ways, as were the risks among first-degree relatives for bipolar I and nonbipolar affective disorders. RESULTS: Familial loading for bipolar affective disorder was not associated with better outcomes during lithium treatment. Rather, the presence of major depressive disorder (MDD) among relatives was associated with slower improvement during acute treatment and with higher symptom levels during continuing treatment. Findings for morbidity during anticonvulsant treatment were similar. The patients who experienced symptom persistence with lithium did so as well during periods of anticonvulsant treatment and during periods without thymoleptics. CONCLUSIONS: A family history of MDD may have an enduring and negative prognostic significance that manifests across treatment conditions. Though difficult to reconcile with several earlier studies, these findings invite replication and further exploration.

Adult↗
PubMed2000

Both increased stability and transcription contribute to the induction of the urokinase plasminogen activator receptor (uPAR) message by hypoxia.

Both hypoxia and overexpression of the urokinase plasminogen activator receptor (uPAR) are associated with a poor clinical outcome in human cancers. Hypoxia has been shown to induce uPAR expression in breast cancer cells and to increase their invasion through Matrigel, a phenomenon which can be blocked using an anti-uPAR antibody. We examined expression of uPAR mRNA in MCF7 human breast carcinoma cells under hypoxia and found that an increase in the level of the message could be detected at 1% oxygen but was most marked at 0.2 or 0.05% oxygen with an induction of 9- to 20-fold over baseline. To determine whether changes in RNA stability contributed to this dramatic increase, we used actinomycin D to inhibit transcription and found that the half-life of the message was much longer under hypoxic conditions (approximately 10 h) than during reoxygenation (approximately 2 h). Transient transfections using a luciferase reporter construct containing 2 kbp of the mouse uPAR promoter showed that promoter activity increased up to 5-fold after exposure to 0.2% oxygen. Thus, hypoxic induction of the uPAR message in MCF7 cells is due to both mRNA stabilization and increased transcriptional activation.

Animals↗
PubMed2000

Benign Paroxysmal Positional Vertigo.

Benign paroxysmal positional vertigo can be diagnosed with great certainty, and treated effectively at the bedside using one of the canalith repositioning procedures described in this paper. This treatment has been shown effective in properly controlled trials, has a rational basis, and has minimal risk.

Journal Article↗