I am fascinated by scientific research, especially at the interface of medicine, biology and behavioral sciences. I am well acquainted with statistical data analysis, both with cross-sectional and longitudinal techniques. Collecting and analyzing data is a difficult puzzle, but the translation to the clinic and to the people who benefit from the control of the research is at least as important. I would like to commit to that.
The amylose-free (amf) potato mutant 86.040 has been characterized phenotypically and genotypical... more The amylose-free (amf) potato mutant 86.040 has been characterized phenotypically and genotypically. Not only storage starch in tubers and metabolic starch in leaves but also starch in cells with specific functions, such as columella cells in the root cap and guard cells of stomata, was amylose-free. Doubled amf-clones of 86.040 flowered well, but the percentage of stainable pollen was low
An amylose-free potato mutant was isolated after screening 12,000 minitubers. These minitubers ha... more An amylose-free potato mutant was isolated after screening 12,000 minitubers. These minitubers had been induced on stem segments of adventitious shoots, which had been regenerated on leaf explants of a monoploid potato clone after Röntgen-irradiation. The mutant character is also expressed in subterranean tubers and in microspores. Starch granules from the mutant showed a strongly reduced activity of the granule
ABSTRACT
The amylose-free (am]} potato clone 86.040 (2n = lx = 12), in which the enzyme granule ... more ABSTRACT
The amylose-free (am]} potato clone 86.040 (2n = lx = 12), in which the enzyme granule bound starch synthase (GBSS) is affected, has been used for the induction and isolation of revertants with loosely branched amylopectin. Screening of 5500
microtubers, which were induced on stem segments of 685 irradiated buds gave in 44 cases reverted sectors from which 22 solid revertants were isolated. However, biochemical analysis showed in all revertants GBSS activity and a compound present
in the starch granules which in all probability was amylose. The frequency of spontaneous reversions in tuber cells of the amf mutant 86.040 lx, 2x and 4x and of amf-mutations in wildtype AM 79.7322 lx, 2x and 4x was investigated indirectly by screening, after iodine staining, for starch granules with altered composition. The amf-mutation occurred at the monoploid- and diploid level. Spontaneous reversions occurred also at the tetraploid level and in high frequencies in older microtubers from monoploid shoots. The reversion frequency in microspores of fertile amfamf-plants appeared to be low.
Background: The locus of control (LOC) construct has been associated with onset, course, and seve... more Background: The locus of control (LOC) construct has been associated with onset, course, and severity of anxiety and depression. We investigated the stability of LOC, the bidirectional relationships between LOC and symptom severity of anxiety and depression over nine years, and the influence of intermediate positive and negative life-events on these associations. Methods: Data came from five assessment waves over nine years of 2052 subjects with an anxiety or depressive disorder or healthy controls. First, the stability of LOC (assessed with 5-item Mastery Scale) was tested. Next, associations between LOC, anxiety severity (Beck Anxiety Inventory), depression severity (Inventory of Depressive Symptomatology), and intermediate positive and negative life-events (20-item List of Threatening Experience Questionnaire) were determined with structural equation modeling. Results: LOC was rather stable over nine years (r = .62), and scores increased slightly with age (i.e. became more intern...
Anxiety sensitivity is associated with the onset of panic attacks, anxiety, and other common ment... more Anxiety sensitivity is associated with the onset of panic attacks, anxiety, and other common mental disorders. Anxiety sensitivity is usually seen as a relative stable trait. However, previous studies were inconclusive regarding the longitudinal stability of anxiety sensitivity and differed in study designs and outcomes. The current study examines the stability of anxiety sensitivity over time and its longitudinal associations with severity of anxiety symptoms. Participants from the Netherlands Study of Depression and Anxiety with and without an anxiety, depressive, or comorbid anxiety-depressive disorder diagnosis were included (N = 2052). Stability in anxiety sensitivity over two year follow-up and the longitudinal association between the change in anxiety sensitivity and change in severity of anxiety symptoms were tested. Results indicated that two-year stability of anxiety sensitivity was high (r = 0.72), yet this test-retest estimate leaves room for changes in anxiety sensitivity in some individuals
as well. Change in anxiety sensitivity was positively associated with change in severity of anxiety symptoms (B = 0.64 in univariable analysis and B = 0.52 in multivariable analysis). The longitudinal association of anxiety sensitivity with severity of anxiety symptoms indicates that targeting anxiety sensitivity may be of additional benefit in clinical practice.
Stability of diagnosis was listed as an important predictive validator for maintaining separate d... more Stability of diagnosis was listed as an important predictive validator for maintaining separate diagnostic classifications in DSM-5. The aim of this study is to examine the longitudinal stability of anxiety disorder diagnoses, and the difference in stability between subjects with a chronic versus a non-chronic course. Longitudinal data of 447 subjects with a current pure anxiety disorder diagnosis at baseline from the Netherlands Study of Depression and Anxiety were used. At baseline, 2-, 4-, and 6-year follow-up mental disorders were assessed and numbers (and percentages) of transitions from one anxiety disorder diagnosis to another were determined for each anxiety disorder diagnosis separately and for subjects with a chronic (i.e. one or more anxiety disorder at every follow-up assessment) and a non-chronic course. Transition percentages were high in all anxiety disorder diagnoses, ranging from 21.1% for social anxiety disorder to 46.3% for panic disorder with agoraphobia at six y...
Despite the substantial disease burden of anxiety disorders, physicians have a poor understanding... more Despite the substantial disease burden of anxiety disorders, physicians have a poor understanding of factors that predict their typical persistent course. This systematic review of predictors of persistent anxiety disorders covered 48 studies with 29 690 patients diagnosed with an anxiety disorder that were published in PubMed, PsycINFO, and Web of Science between Jan 1, 1980 (introduction of DSM-III), and Dec 1, 2019. We also compared predictors between children, adolescents, adults, and older adults (ie, ≥55 years). A persistent course was primarily predicted by clinical and psychological characteristics, including having panic attacks, co-occurring personality disorders, treatment seeking, poor clinical status after treatment, higher severity and longer duration of avoidance behaviour, low extraversion, higher anxiety sensitivity, and higher behavioural inhibition. Unlike disorder onset, sociodemographic characteristics did not predict persistence. Our results outline a profile of patients with specific clinical and psychological characteristics who are particularly vulnerable to anxiety disorder persistence. Clinically, these patients probably deserve additional or more intensive treatment to prevent development of chronicity.
The amylose-free (amf) potato mutant 86.040 has been characterized phenotypically and genotypical... more The amylose-free (amf) potato mutant 86.040 has been characterized phenotypically and genotypically. Not only storage starch in tubers and metabolic starch in leaves but also starch in cells with specific functions, such as columella cells in the root cap and guard cells of stomata, was amylose-free. Doubled amf-clones of 86.040 flowered well, but the percentage of stainable pollen was low
An amylose-free potato mutant was isolated after screening 12,000 minitubers. These minitubers ha... more An amylose-free potato mutant was isolated after screening 12,000 minitubers. These minitubers had been induced on stem segments of adventitious shoots, which had been regenerated on leaf explants of a monoploid potato clone after Röntgen-irradiation. The mutant character is also expressed in subterranean tubers and in microspores. Starch granules from the mutant showed a strongly reduced activity of the granule
ABSTRACT
The amylose-free (am]} potato clone 86.040 (2n = lx = 12), in which the enzyme granule ... more ABSTRACT
The amylose-free (am]} potato clone 86.040 (2n = lx = 12), in which the enzyme granule bound starch synthase (GBSS) is affected, has been used for the induction and isolation of revertants with loosely branched amylopectin. Screening of 5500
microtubers, which were induced on stem segments of 685 irradiated buds gave in 44 cases reverted sectors from which 22 solid revertants were isolated. However, biochemical analysis showed in all revertants GBSS activity and a compound present
in the starch granules which in all probability was amylose. The frequency of spontaneous reversions in tuber cells of the amf mutant 86.040 lx, 2x and 4x and of amf-mutations in wildtype AM 79.7322 lx, 2x and 4x was investigated indirectly by screening, after iodine staining, for starch granules with altered composition. The amf-mutation occurred at the monoploid- and diploid level. Spontaneous reversions occurred also at the tetraploid level and in high frequencies in older microtubers from monoploid shoots. The reversion frequency in microspores of fertile amfamf-plants appeared to be low.
Background: The locus of control (LOC) construct has been associated with onset, course, and seve... more Background: The locus of control (LOC) construct has been associated with onset, course, and severity of anxiety and depression. We investigated the stability of LOC, the bidirectional relationships between LOC and symptom severity of anxiety and depression over nine years, and the influence of intermediate positive and negative life-events on these associations. Methods: Data came from five assessment waves over nine years of 2052 subjects with an anxiety or depressive disorder or healthy controls. First, the stability of LOC (assessed with 5-item Mastery Scale) was tested. Next, associations between LOC, anxiety severity (Beck Anxiety Inventory), depression severity (Inventory of Depressive Symptomatology), and intermediate positive and negative life-events (20-item List of Threatening Experience Questionnaire) were determined with structural equation modeling. Results: LOC was rather stable over nine years (r = .62), and scores increased slightly with age (i.e. became more intern...
Anxiety sensitivity is associated with the onset of panic attacks, anxiety, and other common ment... more Anxiety sensitivity is associated with the onset of panic attacks, anxiety, and other common mental disorders. Anxiety sensitivity is usually seen as a relative stable trait. However, previous studies were inconclusive regarding the longitudinal stability of anxiety sensitivity and differed in study designs and outcomes. The current study examines the stability of anxiety sensitivity over time and its longitudinal associations with severity of anxiety symptoms. Participants from the Netherlands Study of Depression and Anxiety with and without an anxiety, depressive, or comorbid anxiety-depressive disorder diagnosis were included (N = 2052). Stability in anxiety sensitivity over two year follow-up and the longitudinal association between the change in anxiety sensitivity and change in severity of anxiety symptoms were tested. Results indicated that two-year stability of anxiety sensitivity was high (r = 0.72), yet this test-retest estimate leaves room for changes in anxiety sensitivity in some individuals
as well. Change in anxiety sensitivity was positively associated with change in severity of anxiety symptoms (B = 0.64 in univariable analysis and B = 0.52 in multivariable analysis). The longitudinal association of anxiety sensitivity with severity of anxiety symptoms indicates that targeting anxiety sensitivity may be of additional benefit in clinical practice.
Stability of diagnosis was listed as an important predictive validator for maintaining separate d... more Stability of diagnosis was listed as an important predictive validator for maintaining separate diagnostic classifications in DSM-5. The aim of this study is to examine the longitudinal stability of anxiety disorder diagnoses, and the difference in stability between subjects with a chronic versus a non-chronic course. Longitudinal data of 447 subjects with a current pure anxiety disorder diagnosis at baseline from the Netherlands Study of Depression and Anxiety were used. At baseline, 2-, 4-, and 6-year follow-up mental disorders were assessed and numbers (and percentages) of transitions from one anxiety disorder diagnosis to another were determined for each anxiety disorder diagnosis separately and for subjects with a chronic (i.e. one or more anxiety disorder at every follow-up assessment) and a non-chronic course. Transition percentages were high in all anxiety disorder diagnoses, ranging from 21.1% for social anxiety disorder to 46.3% for panic disorder with agoraphobia at six y...
Despite the substantial disease burden of anxiety disorders, physicians have a poor understanding... more Despite the substantial disease burden of anxiety disorders, physicians have a poor understanding of factors that predict their typical persistent course. This systematic review of predictors of persistent anxiety disorders covered 48 studies with 29 690 patients diagnosed with an anxiety disorder that were published in PubMed, PsycINFO, and Web of Science between Jan 1, 1980 (introduction of DSM-III), and Dec 1, 2019. We also compared predictors between children, adolescents, adults, and older adults (ie, ≥55 years). A persistent course was primarily predicted by clinical and psychological characteristics, including having panic attacks, co-occurring personality disorders, treatment seeking, poor clinical status after treatment, higher severity and longer duration of avoidance behaviour, low extraversion, higher anxiety sensitivity, and higher behavioural inhibition. Unlike disorder onset, sociodemographic characteristics did not predict persistence. Our results outline a profile of patients with specific clinical and psychological characteristics who are particularly vulnerable to anxiety disorder persistence. Clinically, these patients probably deserve additional or more intensive treatment to prevent development of chronicity.
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Papers by Ans Hovenkamp
The amylose-free (am]} potato clone 86.040 (2n = lx = 12), in which the enzyme granule bound starch synthase (GBSS) is affected, has been used for the induction and isolation of revertants with loosely branched amylopectin. Screening of 5500
microtubers, which were induced on stem segments of 685 irradiated buds gave in 44 cases reverted sectors from which 22 solid revertants were isolated. However, biochemical analysis showed in all revertants GBSS activity and a compound present
in the starch granules which in all probability was amylose. The frequency of spontaneous reversions in tuber cells of the amf mutant 86.040 lx, 2x and 4x and of amf-mutations in wildtype AM 79.7322 lx, 2x and 4x was investigated indirectly by screening, after iodine staining, for starch granules with altered composition. The amf-mutation occurred at the monoploid- and diploid level. Spontaneous reversions occurred also at the tetraploid level and in high frequencies in older microtubers from monoploid shoots. The reversion frequency in microspores of fertile amfamf-plants appeared to be low.
as well. Change in anxiety sensitivity was positively associated with change in severity of anxiety symptoms (B = 0.64 in univariable analysis and B = 0.52 in multivariable analysis). The longitudinal association of anxiety sensitivity with severity of anxiety symptoms indicates that targeting anxiety sensitivity may be of additional benefit in clinical practice.
The amylose-free (am]} potato clone 86.040 (2n = lx = 12), in which the enzyme granule bound starch synthase (GBSS) is affected, has been used for the induction and isolation of revertants with loosely branched amylopectin. Screening of 5500
microtubers, which were induced on stem segments of 685 irradiated buds gave in 44 cases reverted sectors from which 22 solid revertants were isolated. However, biochemical analysis showed in all revertants GBSS activity and a compound present
in the starch granules which in all probability was amylose. The frequency of spontaneous reversions in tuber cells of the amf mutant 86.040 lx, 2x and 4x and of amf-mutations in wildtype AM 79.7322 lx, 2x and 4x was investigated indirectly by screening, after iodine staining, for starch granules with altered composition. The amf-mutation occurred at the monoploid- and diploid level. Spontaneous reversions occurred also at the tetraploid level and in high frequencies in older microtubers from monoploid shoots. The reversion frequency in microspores of fertile amfamf-plants appeared to be low.
as well. Change in anxiety sensitivity was positively associated with change in severity of anxiety symptoms (B = 0.64 in univariable analysis and B = 0.52 in multivariable analysis). The longitudinal association of anxiety sensitivity with severity of anxiety symptoms indicates that targeting anxiety sensitivity may be of additional benefit in clinical practice.