The Depression-Happiness Scale: happiness is not hypomania.
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
S Kaplan
Publications and source records attributed to S Kaplan.
Depression, mania, and suicidal preoccupation.
Explore the source record for details and available documents.
Adolescent↗
Diurnal changes in plasma lipoproteins of free-living healthy men consuming a standard diet.
Although it is well established that plasma lipoproteins are involved in atherogenesis, most patients with coronary heart disease have normal or nearly normal fasting plasma lipid and lipoprotein levels. As most of the human life is spent in the fed state we elected to investigate the changes occurring in plasma lipids and lipoproteins during normal daily activities. We studied 12 healthy, normolipidemic and non-obese subjects on a standard diet divided into three meals and three snacks. This method was found to be accurate and reproducible in four subjects who underwent repeated studies. The major diurnal changes were observed in plasma triglyceride level and in the composition of plasma lipoproteins. The degree and pattern of these changes differed among subjects but was specific and constant for each individual. The extent of these diurnal changes, which correlated positively with fasting plasma triglyceride and inversely with plasma HDL2 levels, may play an important role in the pathogenesis of atherosclerosis.
Activities of Daily Living↗
Hyperplasia and apoptosis. Opposing cellular processes that regulate the response of the rabbit bladder to transient outlet obstruction.
BACKGROUND: Partial obstruction of the rabbit urethra induces rapid bladder growth. This growth is characterized by hypertrophy of smooth muscle cells in addition to hyperplasia of cells in the urothelium and serosa. The local synthesis of growth factors has been proposed to be influential in this growth since partial outlet obstruction rapidly increases the bladder's expression of basic fibroblast growth factor, while suppressing the expression of transforming growth factor-beta. Upon release of the outlet obstruction, the hypertrophied bladder regresses to its normal weight. Here, we examined whether regression of the hypertrophied rabbit bladder involves apoptosis (programmed cell death) of specific cellular elements and whether the expression of growth factors is altered concomitant with apoptotic cell deletion. EXPERIMENTAL DESIGN: Regressing rabbit bladders were analyzed for markers of apoptosis, including DNA fragmentation and histology. An in situ enzymatic immuno-histochemical procedure was utilized to localize apoptotic cells in these tissues. Finally, Northern blot analysis was used to identify changes in the expression of basic fibroblast growth factor and transforming growth factor-beta during bladder regression. RESULTS: Regressing rabbit bladders demonstrated the characteristic electrophoretic "ladder" pattern of DNA fragmentation associated with apoptosis. An in situ technique to distinguish cells with degraded nuclear DNA identified apoptosis only within the urothelium and serosal lamina of the regressing bladders. RNAs extracted from regressing bladders exhibited decreased expression of basic fibroblast growth factor mRNA as well as increased expression of transforming growth factor-beta 1 mRNA when compared with RNAs from hypertrophied bladders. CONCLUSIONS: We conclude that hyperplasia and apoptosis are opposing cellular processes that mediate the bladder's response to short-term obstructive stimuli and that local synthesis of growth-promoting and growth-inhibitory factors may be responsible for initiating both of these responses.
Animals↗
Transcriptional regulation of puc operon expression in Rhodobacter sphaeroides. Involvement of an integration host factor-binding sequence.
The putative overlapping consensus sequences (-129 to -105) for binding of fumarate nitrate reductase regulator- and integration host factor (IHF)-like proteins to puc operon upstream DNA of Rhodobacter sphaeroides was protected from DNase I digestion by purified Escherichia coli IHF. The binding of E. coli IHF to the purported IHF-binding site in the puc upstream DNA is highly sequence-specific. The recorded binding affinity was significantly lower than that of E. coli IHF to the lambda attP site. Employing site-directed changes in the DNA sequence within the -129 to -105 region, a loss in IHF binding, as monitored through gel retardation analysis, was correlated with alterations in puc operon expression monitored through the use of puc::lacZ transcriptional fusions. These results suggest that the IHF-binding site is involved in repression of puc operon transcription by oxygen as well as modulation of puc operon transcription levels by incident light intensity. Mutations specific to the upstream half of the putative fumarate nitrate reductase regulator-binding site of the puc upstream DNA did not show any physiological effects under the experimental conditions employed. Taken together, these studies reveal that the DNA sequence between -129 to -105 may involve facilitation of the interaction between upstream and downstream cis-acting regulatory sequences involved in puc operon expression.
Bacterial Proteins↗
Synthesis and stability of reaction center polypeptides and implications for reaction center assembly in Rhodobacter sphaeroides.
The synthesis and stability of the H and M polypeptide subunits of the photosynthetic reaction center of Rhodobacter sphaeroides were examined. In wild-type cells, low levels of both M and H were found to be synthesized under aerobic growth conditions, with a 20-fold induction in their synthesis under anaerobic-dark growth conditions. Neither M nor H was stable in aerobic cells, but in anaerobic-dark grown cells stability increased dramatically with the t1/2 going from 4-6 min to values estimated in excess of 4 h. In the H-deficient mutant PUHA1, the synthesis and membrane partitioning of the M subunit were unaffected by the absence of the H subunit but there was a significant decrease in M polypeptide stability in the membranes of PUHA1 relative to wild-type cells. The stability of all or part of the M population in PUHA1 could be restored by providing an H-encoding plasmid in trans. It was also determined that the presence of bacteriochlorophyll in fully aerobic cells had a direct, positive effect on M and H stability, utilizing the oxygen-regulatory mutant strain T1a. Implications for the role of the H subunit and putative assembly factors in reaction center assembly are discussed.
Aerobiosis↗
Grb2 mediates the EGF-dependent activation of guanine nucleotide exchange on Ras.
Activation of receptor tyrosine kinases such as those for epidermal growth factor (EGF), platelet-derived growth factor, or nerve growth factor converts the inactive, GDP-bound form of Ras to the active, GTP-bound form, and a dominant negative mutant of Ras interferes with signalling from such receptors. The mechanisms by which receptor tyrosine kinases and Ras are coupled, however, are not well understood. Many cytoplasmic proteins regulated by such receptors contain Src-homology (SH) 2 and 3 domains, and the SH2- and SH3-containing protein Grb2, like its homologue from Caenorhabditis elegans, Sem-5, appears to play an important role in the control of Ras by receptor tyrosine kinases. Here we show that overexpression of Grb2 potentiates the EGF-induced activation of Ras and mitogen-activated protein kinase by enhancing the rate of guanine nucleotide exchange on Ras. Cellular Grb2 appears to form a complex with a guanine-nucleotide-exchange factor for Ras, which binds to the ligand-activated EGF receptor, allowing the tyrosine kinase to modulate Ras activity.
3T3 Cells↗
Proptosis and periorbital edema due to diltiazem treatment.
Explore the source record for details and available documents.
Aged↗
Monoclonal IgM, IgG, and IgA human rheumatoid factors produced by synovial tissue-derived, EBV-transformed B cell lines.
In an effort to study disease-related autoantibodies in rheumatoid arthritis (RA), rheumatoid factor (RF)-producing B cell lines were developed from the heterogeneous B cell populations infiltrating the synovial tissue of patients with arthritis. Over 125 EBV-transformed B cell cultures were derived from three patients: one with early pre-erosive RA, one with advanced RA, and one with osteoarthritis (OA). IgM, IgG, and IgA RF-producing B cell lines were found in all three series but with several significant differences. In each of the two RA patients, 22% of the Ig-producing cell lines secreted RF compared to 7% in the OA patient. The isotypes of these RF were mostly IgM in the early RA (62%) and the OA patient (60%) as contrasted to predominantly IgA (75%) and, to a lesser extent, IgG (12.5%) in the advanced RA patient. Analyses of the light (L) chain composition of these RF revealed that 82% of the IgM RF used kappa L chains whereas only 31% of the non-IgM RF used kappa chains. Antigen-binding analyses of these RF revealed that all the synovial tissue-derived RF from the advanced RA patient exhibited antigen binding specificities restricted to a narrow range of gamma globulins. In contrast, the synovial RF of the other two patients were either reactive with a broader spectrum of gamma globulins or reactive with a variety of unrelated antigens. In every instance, the gamma globulin-specific RF were of all three major isotypes whereas the polyreactive RF were restricted to the IgM isotype. These data demonstrate that synovial B cells from both RA and OA patients can produce RF and that significant differences can exist among patients in the percentage of RF generated and their H and L chain isotype distribution. The reversal of the kappa:lambda ratio among the IgG and IgA RF and the more restricted antigen-binding specificities of the IgG and IgA vs IgM RF suggest that a non-stochastic, possibly antigen-driven selection process was involved in their generation. The relevance of these differences in RF precursor frequency, H and L chain distribution, and antigen specificity to these two diseases warrants further investigation.
Aged↗
The direct effect of graft compliance mismatch per se on development of host arterial intimal hyperplasia at the anastomotic interface.
To study the direct and sole effect of compliance mismatch on anastomotic intimal hyperplasia of the host arterial wall and to minimize possible confounding factors, dogs with a low thrombotic potential were selected as experimental subjects. Externally supported 6 cm x 5 mm Dacron grafts with a compliance value of approximately 1/300 of the host artery were implanted into the carotid arteries with end-to-end anastomoses on one side and end-to-side anastomoses on the other. The control graft was an autogenous carotid artery segment 4 cm in length transplanted into the femoral artery. Eight cases (24 grafts) were studied for 1 year and three (nine grafts) for 6 months. All were patent throughout the study period except for two noncompliant grafts with end-to-end anastomoses; thrombosis was the documented cause of occlusion. For the patent grafts, follow-up arteriograms showed no progressive narrowing of noncompliant anastomoses. Whether compliant or noncompliant, light microscopy studies showed slight intimal thickening within 1 to 2 mm of the anastomotic line, possibly the result of the normal healing response to stitch and surgical trauma. Quantitatively, 22 measurements representing longitudinal and circumferential thickness of the neointima were taken at each of the 40 patent noncompliant and 22 patent compliant control anastomoses. There was no statistically significant difference in anastomotic neointimal thickness in compliant and noncompliant grafts or for the different implantation periods. These data suggest that graft/host artery compliance mismatch does not cause arterial intimal hyperplasia at the anastomotic interface.
Anastomosis, Surgical↗
Airport X-rays and floppy disks: no cause for concern.
A controlled study was done to test the possible effects of X-rays on the integrity of data stored on common sizes of floppy disks. Disks were exposed to doses of X-rays up to seven times that to be expected during airport examination of baggage. The readability of nearly 14 megabytes of data was unaltered by X-irradiation, indicating that floppy disks need not be given special handling during X-ray inspection of baggage.
Aviation↗
Physicians' characteristics influence patients' adherence to medical treatment: results from the Medical Outcomes Study.
The influence of physicians' attributes and practice style on patients' adherence to treatment was examined in a 2-year longitudinal study of 186 physicians and their diabetes, hypertension, and heart disease patients. A physician-level analysis was conducted, controlling for baseline patient adherence rates and for patient characteristics predictive of adherence in previous analyses. General adherence and adherence to medication, exercise, and diet recommendations were examined. Baseline adherence rates were associated with adherence rates 2 years later. Other predictors were physician job satisfaction (general adherence), number of patients seen per week (medication), scheduling a follow-up appointment (medication), tendency to answer patients' questions (exercise), number of tests ordered (diet), seriousness of illness (diet), physician specialty (medication, diet), and patient health distress (medication, exercise).
Adult↗
Platelet aggregometry can accurately predict failure of externally supported knitted Dacron femoropopliteal bypass grafts.
PURPOSE: Our purpose was to evaluate whether a method for quantification of platelet aggregability will predict failure of knitted Dacron femoropopliteal bypass grafts. METHODS: A numerically derived platelet aggregation (PA) score, based on the aggregation pattern and platelet count, was determined in the 40 patients available for platelet analysis who underwent 53 femoropopliteal bypass grafts with preclotted, 6 mm, externally supported knitted Dacron grafts from 1981 to 1991 (mean follow-up 50 months). The preoperative score was found to remain stable after surgery, enabling the use of postoperative values when preoperative values were not available. The PA score was available in 19 patients (23 grafts) before surgery and 23 patients (30 grafts) after surgery. The following factors were analyzed for predicting graft failure by the Cox proportional hazards regression model: PA score, age, gender, history of smoking, coronary artery disease, hypertension, hyperlipidemia, cerebrovascular disease, diabetes, claudication versus limb salvage, site of the distal anastomosis, previous ipsilateral bypass, and state of the runoff as determined by preoperative angiography. RESULTS: Of the studied risk factors, the value of the PA score was the most significant predictor of graft closure (p < 0.0001). An increase of 10 units was associated with an increased relative risk of 2.02. Throughout the follow-up period, 15 of 16 grafts remained patent in patients with a PA score of 15 or less, but only 2 grafts out of 17 remained patent in patients with a PA score of 30 or greater. CONCLUSIONS: These data suggest that the PA score is a potential risk factor for failure of femoropopliteal bypass with externally supported knitted Dacron grafts.
Adenosine Diphosphate↗
Cloning, nucleotide sequence and characterization of the mannitol dehydrogenase gene from Rhodobacter sphaeroides.
Transposon mutagenesis and antibiotic enrichment were employed to isolate a mutant of Rhodobacter sphaeroides Si4 designated strain M22, that had lost the ability to grow on D-mannitol and to produce the enzyme mannitol dehydrogenase (MDH). DNA flanking the transposon in the mutant strain was used as a probe for the identification and cloning of the MDH gene (mtlK). A 5.5 kb EcoRI/BglII fragment from R. sphaeroides Si4 was isolated and shown to complement the mutation in R. sphaeroides M22. Successful complementation required that a promoter of the vector-plasmid pRK415 be present, suggesting that the mtlK gene is part of a larger operon. Using oligonucleotides derived from the N-terminal sequence of MDH as probes mtlK was located on the complementing fragment and the gene was sequenced. The mtlK open reading frame encodes a protein of 51,404 Da with an N-terminal sequence identical to that obtained from amino acid analysis of the purified MDH. The MDH of R. sphaeroides Si4 exhibits distant similarity to the mannitol-1-phosphate dehydrogenases from Escherichia coli and Enterococcus faecalis, with 28.1% and 26.3% identity, respectively. Mutant strains deficient in MtlK displayed substantial levels of sorbitol dehydrogenase activity, originally thought to be only a minor activity associated with the MDH enzyme. It is likely that we have uncovered an additional polyol dehydrogenase with activity for sorbitol. The mtlK gene can be used for overexpression of MDH in E. coli in order to obtain sufficient amounts of enzyme for further investigations and applications.
Amino Acid Sequence↗
Identification of cis-acting regulatory regions upstream of the rRNA operons of Rhodobacter sphaeroides.
The promoter region(s) for the rRNA operons of Rhodobacter sphaeroides was identified. By utilizing both in vivo and in vitro techniques, the transcriptional start sites of all three operons were identified. Upstream of the transcriptional start, -10 and -35 promoter regions that bear little similarity to typical Escherichia coli promoter sequences were identified. In addition to the promoter sequences, probable Fis protein-binding sites were identified upstream of all three rRNA operons. Transcriptional fusions of the promoter regions from rrnA and rrnB were constructed by utilizing the reporter molecule encoded by xylE and analyzed under various growth conditions, in both a wild-type background and an rrnBC mutant background. Production of the xylE gene product (catechol 2,3-dioxygenase) was always greatest under photosynthetic growth conditions. However, the upstream region of rrnB, when fused with xylE, produced significantly more catechol 2,3-dioxygenase than did analogous regions of rrnA, suggesting that the promoters of the rrn operons differ in strength. These results were further confirmed by the study of mutant strains altered for the rrn operons either singly or in combination. Little or no expression of the xylE gene was manifest in E. coli when directed by rDNA sequences derived from R. sphaeroides.
Base Sequence↗
Expression of the Rhodobacter sphaeroides hemA and hemT genes, encoding two 5-aminolevulinic acid synthase isozymes.
The nucleotide sequences of the Rhodobacter sphaeroides hemA and hemT genes, encoding 5-aminolevulinic acid (ALA) synthase isozymes, were determined. ALA synthase catalyzes the condensation of glycine and succinyl coenzyme A, the first and rate-limiting step in tetrapyrrole biosynthesis. The hemA and hemT structural gene sequences were 65% identical to each other, and the deduced HemA and HemT polypeptide sequences were 53% identical, with an additional 16% of aligned amino acids being similar. HemA and HemT were homologous to all characterized ALA synthases, including two human ALA synthase isozymes. In addition, they were evolutionarily related to 7-keto-8-aminopelargonic acid synthetase (BioF) and 2-amino-3-ketobutyrate coenzyme A ligase (Kbl), enzymes which catalyze similar reactions. Two hemA transcripts were identified, both expressed under photosynthetic conditions at levels approximately three times higher than those found under aerobic conditions. A single transcriptional start point was identified for both transcripts, and a consensus sequence at this location indicated that an Fnr-like protein may be involved in the transcriptional regulation of hemA. Transcription of hemT was not detected in wild-type cells under the physiological growth conditions tested. In a mutant strain in which the hemA gene had been inactivated, however, hemT was expressed. In this mutant, hemT transcripts were characterized by Northern (RNA) hybridization, primer extension, and ribonuclease protection techniques. A small open reading frame of unknown function was identified upstream of, and transcribed in the same direction as, hemA.
5-Aminolevulinate Synthetase↗
5-Aminolevulinic acid availability and control of spectral complex formation in hemA and hemT mutants of Rhodobacter sphaeroides.
In the photosynthetic bacterium Rhodobacter sphaeroides, two genes, hemA and hemT, each encode a distinct 5-aminolevulinic acid (ALA) synthase isozyme (E. L. Neidle and S. Kaplan, J. Bacteriol. 175:2292-2303, 1993). This enzyme catalyzes the first and rate-limiting step in a branched pathway for tetrapyrrole formation, leading to the biosynthesis of hemes, bacteriochlorophylls, and corrinoids. In an attempt to determine the functions of hemA and hemT, mutant strains were constructed with specific chromosomal disruptions. These chromosomal disruption allowed hemA and hemT to be precisely localized on the larger and smaller of two R. sphaeroides chromosomes, respectively. Mutants carrying a single hemA or hemT disruption grew well without the addition of ALA, whereas a mutant, HemAT1, in which hemA and hemT had both been inactivated required exogenous ALA for growth. The growth rates, ALA synthase enzyme levels, and the amounts of bacteriochlorophyll-containing intracytoplasmic membrane spectral complexes of all strains were compared. Under photosynthetic growth conditions, the levels of bacteriochlorophyll, carotenoids, and B800-850 and B875 light-harvesting complexes were significantly lower in the Hem mutants than in the wild type. In the mutant strains, available bacteriochlorophyll appeared to be preferentially targeted to the B875 light-harvesting complex relative to the B800-850 complex. In strain HemAT1, the amount of B800-850 complex varied with the concentration of ALA added to the growth medium, and under conditions of ALA limitation, no B800-850 complexes could be detected. In the Hem mutants, there were aberrant transcript levels corresponding to the puc and puf operons encoding structural polypeptides of the B800-850 and B875 complexes. These results suggest that hemA and hemT expression is coupled to the genetic control of the R. sphaeroides photosynthetic apparatus.
5-Aminolevulinate Synthetase↗
Congenital heart disease in adolescents and adults. Natural and postoperative history across age groups.
Advances in the diagnosis and treatment of heart disease have significantly affected survival patterns. Many adults with these anomalies have never had cardiac surgery because they have not required operation, their lesions are treatable in adulthood, or they are inoperable. A large number have reached adult life after undergoing cardiovascular surgery in infancy and childhood. Generally, results in these patients are gratifying, but cure is seldom achieved, and many have important sequelae and residua.
Aging↗