Search

Hoefnagels, M. H., and Linderman, R. G. 1999. Biological s uppression of seedborne Fusarium spp. during cold stratification of Douglas fir seeds. Plant Dis. 83:845-852. Fusarium spp. are important soil- and seedborne pathogens of Douglas fir ( Pseudotsuga menziesii) in conifer seedling nurseries. We investigated the effects of culture media and cold stratification on isolation of Fusarium spp. from three Douglas fir seedlots and tested whether the numbers and species mixtures found on stratified seeds could cause disease. Nearly all coldstratified seeds plated on three semiselective culture media yielded Fusarium spp., including F. avenaceum, F. culmorum, F. lateritium, F. moniliforme, F. F. proliferatum, F. sambucinum, F. solani, and F. tricinctum. Species composition did not differ significantly among the media. Isolation of Fusarium spp. from seeds plated on Komada’s medium (pH 6.8) at various stages of imbibition and cold stratification progressively increased from 10 to 22% to 65 to 100%. When stratified seeds were planted in conditions conducive to disease development, however, little disease attributable to Fusarium spp. resulted. A subsequent study was conducted to determine whether a biological control agent applied during imbibition could reduce the proliferation of Fusarium spp. during stratification. Unstratified Douglas fir seeds were imbibed for 24 h in a suspension of Pseudomonas chlororaphis isolate RD31-3A, a rifampicin-resistant fluorescent pseudomonad with previously demonstrated biocontrol activity against F. oxysporum. This treatment reduced the proliferation of Fusarium spp. during cold stratification without significantly affecting subsequent seed germination. The greatest reduction in poststratification populations of seedborne Fusarium spp. was achieved when preimbibition treatment with hydrogen peroxide was followed by seed imbibition in live bacteria. Seed imbibition in bacterial suspensions may be an effective means to deliver biological control agents to Douglas fir seeds.

Vitamin B-12 deficiency is associated with cognitive impairment in older people. However, evidence from randomized trials of the effects of vitamin B-12 supplementation on cognitive function is limited and inconclusive.The objective was to investigate whether daily supplementation with high doses of oral vitamin B-12 alone or in combination with folic acid has any beneficial effects on cognitive function in persons aged/=70 y with mild vitamin B-12 deficiency.In a double-blind, placebo-controlled trial, 195 subjects were randomly assigned to receive 1000 microg vitamin B-12, 1000 microg vitamin B-12 + 400 microg folic acid, or placebo for 24 wk. Vitamin B-12 status was assessed on the basis of methylmalonic acid, total homocysteine (tHcy), and holotranscobalamin (holoTC) concentrations before and after 12 and 24 wk of treatment. Cognitive function was assessed before and after 24 wk of treatment with the use of an extensive neuropsychologic test battery that included the domains of attention, construction, sensomotor speed, memory, and executive function.Vitamin B-12 status did not change significantly after treatment in the placebo group; however, oral vitamin B-12 supplementation corrected mild vitamin B-12 deficiency. Vitamin B-12 + folic acid supplementation increased red blood cell folate concentrations and decreased tHcy concentrations by 36%. Improvement in memory function was greater in the placebo group than in the group who received vitamin B-12 alone (P = 0.0036). Neither supplementation with vitamin B-12 alone nor that in combination with folic acid was accompanied by any improvement in other cognitive domains.Oral supplementation with vitamin B-12 alone or in combination with folic acid for 24 wk does not improve cognitive function.

Between January 1994 and November 1997, 17 children with 25 clubfeet were treated and evaluated. This group was divided into a group of only conservatively treated feet (group A, n=13) and a group of feet which had conservative treatment and complementary operative treatment (group B, n=12). Both groups were evaluated according to the Diméglio classification method in which the objective clinical evaluation is scored only. This was performed for the starting-point (at presentation until 2 weeks after birth), with the necessary information received from the patient's files where all the passive limitations were recorded in a standardized way and also for the end-point (at the time of the follow-up). After comparing these results to each other, all 25 feet had improved after treatment and the operative group had improved more than the conservative group, however the end result was equal, because the operated feet were more severely deformed before the treatment. After treatment, the results were considered acceptable in 92% of the feet, comparable to 93%, 75-85%, 88%, 77%, and 96% in other studies. Moreover, the forefoot adduction was the most common residual sign in the treated feet, confirmed by results in other studies. We conclude that the Diméglio method is an appropriate tool for the follow-up of clubfeet from birth to the end of treatment.

Quantification of hypovolemia by physical examination has limited validity. We explored the use of non-invasive measurement of blood pressure (BP) response to Valsalva's maneuver in monitoring hypovolemia in nine healthy elderly volunteers, recruited from participants of the Nijmegen Annual Four-Days Marches. Heart rate (HR), systolic and diastolic BP, and mean arterial pressure (MAP) response (Finapres) to a Valsalva's maneuver as well as clinical and laboratory assessment of fluid balance were determined 5 minutes before, and 3, 5, and 48 hours after administration of 40 mg furosemide orally. Subjects' (4 males aged 74.2 +/- 3.0 years) weight was 66.1 +/- 9.7 kg, mean BP was 139 +/- 21 over 76 +/- 12 mm Hg. A maximum weight loss of -2.8 +/- 0.9% occurred 5 hours after furosemide administration. Systolic and diastolic BP, HR, clinical assessment scores, and serum creatinine and urea nitrogen did not change during the total study period. Significant changes occurred in Valsalva phase I to phase II systolic BP response (difference +14.2 +/- 11.3 mm Hg, ratio difference -0.09 +/- 0.07 after 5 hours, P0.01). Changes after 48 hours did not differ from baseline values. Finapres measurement of Valsalva BP response may be useful in monitoring hypovolemia in the elderly.

We performed a prospective, randomised double-blind study in 24 patients undergoing high tibial osteotomy to evaluate the effectiveness of human recombinant osteogenic protein (OP-1) on a collagen type-I carrier in a critically-sized fibular defect. The study had two phases, each evaluated by clinical, radiological and DEXA methods during the first postoperative year. The first concerned the validation of the model of the fibular defect, using positive (demineralised bone) and negative (untreated) controls. The second phase concerned the osteogenic potential of OP-1 on collagen type-I v collagen type-I alone. The results of the first phase established the critically-sized nature of the defect. In the untreated group no bony changes were observed while, in the demineralised bone group, formation of new bone was visible from six weeks onwards. The results of the second phase showed no significant formation of new bone in the presence of collagen alone, while in the OP-1 group, all patients except one showed formation of new bone from six weeks onwards. This proved the osteogenic activity of OP-1 in a validated critically-sized human defect.

To describe the methodological development of medical research regarding elderly subjects in the Netherlands.Descriptive.Nijmegen University, the Netherlands.All research on aging published in the Netherlands Tijdschrift voor Geneeskunde (Dutch Journal of Medicine) starting from its first volume in 1857 up to 1983 was studied. Selected were those articles in which new research methods were introduced. Next, six pioneering researchers in geriatrics were interviewed on the methodological development of geriatric research and on the problems they encountered in their own research.Research started with studies on age-associated diseases such as prostatism, presbyacusis and senile dementia. It was only after a considerable delay that new diagnostic instruments such as electrocardiography and new research designs such as randomized trials found their way into research on elderly patients. The development of a questionnaire on the health of the elderly, the introduction of the concept of activities of daily living and of diagnostic instruments in the field of psychogeriatrics were important steps that made possible current geriatric research. From the outset, researchers encountered methodological problems still relevant in current research and caused by characteristics of geriatric patients: frailty, high prevalence of comorbidity, coexistence of physical, psychological and social problems, and large interindividual differences.

To study the effect of theophylline use on the vitamin B-6 status.Descriptive.Department of Geriatric Medicine of Nijmegen Academic Hospital and Department of Pulmonary Diseases, University of Nijmegen, the Netherlands.Vitamin B-6 status was determined by measuring pyridoxal-5'-phosphate (PLP) in whole blood (using a high performance liquid chromatography method, reference values: 35-107 mumol/l) in 141 patients from the Geriatric department (84 non-chronic obstructive pulmonary disease (COPD), 40 COPD patients without theophylline and 17 COPD patients with theophylline) and in 25 non-geriatric COPD patients on theophylline.Of the 84 geriatric non-COPD patients (mean age: 82 years; SD: 6) 56% had a subnormal vitamin B-6 status, of the 40 geriatric COPD patients without theophylline (82 years; SD: 6) 70%, of the 17 geriatric COPD patients on theophylline (80 years; SD: 5) 94% and of the 25 non-geriatric COPD patients on theophylline (62 years; SD: 11) 96%.In patients who used theophylline a higher prevalence of subnormal vitamin B-6 status was found than in patients who did not.

The conduct of research in geriatric medicine differs from that in other medical specialties in a number of ways. In geriatric research it is almost impossible to study a large, homogeneous group of subjects, suffering solely from the problem to be studied. Moreover, measurements and questionnaires should be short, simple and not very troublesome. These differences are due to the heterogeneity of geriatric patients and the high prevalence of multimorbidity, often resulting in impaired physical, psychological and social performance. In this article a number of issues which are important for successful recruitment and selection of subjects for geriatric research are discussed. First, a review of relevant literature is given, and subsequently, experiences concerning recruitment and selection appreciated in the Nijmegen geriatric research programme' are described. This programme was part of the governmental Netherlands Programme for Research on Ageing (NESTOR). According to the literature the efficacy of recruitment may be improved by: personal contact between researcher and subject in view, introduction of the selection criteria already at the time of subjects' recruitment, a balance between research burden and profit, sufficient rewards for participation, both financially and non-financially, maximal effort in the subjects' transport, and also piloting of the recruitment procedure. In the NESTOR-studies the average number of subjects who were recruited and who completed the studies was low (23%), because a lot of the recruited subjects did not meet the selection criteria or considered participation as too troublesome. Subjects who agreed to participate showed high research compliance.

We present the 5.6- to 7.6-year results of our first 118 hydroxyapatite (HA)-coated total hip replacements in patients under 66 years of age. The titanium femoral component has proximal HA coating and was usually articulated with an HA-coated threaded cup. The HA coating of 50 microns thickness has a porosity of below 3%, 97% HA purity and 65% crystallinity. The survival rate at a mean of six years was 100% for the HA-coated stems and 99% for the HA-threaded cups. The average Harris hip score at one year was 96, and at three years and thereafter 98. There was a very low incidence of early pain after surgery. Serial radiographs showed rapid bony integration of implants with evidence of bone apposition on the coating within six months. By Engh's criteria, all the femoral components had confirmed bone ongrowth after three years. We found no deterioration of results with time, and consider that our clinical and radiological results show that HA coatings can provide early pain relief and durable implant fixation.

To investigate the effect of early identification of hospitalised patients with an increased risk of falling and of preventive measures on the frequency of falling.Ten medical units (two neurology, five internal medicine, three surgery; 276 beds) in the St. Radboud Hospital in Nijmegen.In a first case control study (5 months), a slightly modified falling risk index of Innes and Turman was validated. In a following (5.5 months) study period the index was computed for every hospitalised patient. Preventive measures were used in patients with a high score. The numbers of falls in both study periods were compared. All falls were carefully documented.High scores on the index were significantly associated with falls (p0.001). In both study periods (1 and 2) sensitivity (87% and 89%) and specificity (82% and 74%) of the index were high. A significant reduction in fall rate, 86 falls in period 1 versus 66 in period 2, was achieved, (corrected for number of patients and patient days).The modified index is a useful instrument for early identification of patients with a substantial risk of falling in the hospital. Early risk identification and preventive measures were successful in reducing the number of falls.

The aim of this study was to evaluate tests predicting renovascular hypertension. This was done by relating the results of renal vein renin tests, the captopril test, and renal scintigraphic tests to the blood pressure outcome 12 months after relief of renal artery stenosis by percutaneous transluminal renal angioplasty in 31 patients. Cure was seen in eight (26%). Improved blood pressure was obtained in 12 patients (39%), and in 11 patients (35%), the result for blood pressure was a failure. The accuracies of the two mathematical models used to analyze the renal vein renin assays were 44% and 60%. The captopril test showed a sensitivity of 36% and an accuracy of 43%. Renal captopril technetium Tc 99m-labeled pentetic acid scintigraphy gave a sensitivity of 60%. Stepwise logistic regression analysis of clinical variables in relation to blood pressure response revealed age as the only factor significantly related to blood pressure outcome. We conclude that the tests used are unfit for helping select patients for percutaneous transluminal renal angioplasty and that age may have an important influence on outcome.

Recently it has been shown that, after a meal, blood pressure may fall in the elderly, in patients with autonomic failure and in patients on haemodialysis. This review deals with the available data on postprandial blood pressure reduction, the clinical significance and some pathophysiological hypotheses. The mechanism is not fully understood, but postprandial blood pressure reduction seems to be related to glucose related factors, since blood pressure only falls after oral glucose loading, but not after oral fructose, fat or protein loading. Vasoactive gastrointestinal peptides may play a role in the glucose induced vasodilation of splanchnic vasculature, but attempts to identify such peptides have been unsuccessful. The role of insulin in postprandial blood pressure reduction remains to be elucidated, but it does not appear to have any influence on systemic vasodilation or baroreflex response. Although the clinical significance of postprandial blood pressure reduction remains uncertain, patients can be advised in several ways on how to avoid this symptom. Treatment of hypertension, small carbohydrate meals, caffeine and treatment with the somatostatin analogue SMS 201-995 may have a beneficial effect. Patients on haemodialysis with symptomatic hypotension should not consume meals during the procedure.

The primary objective of this research was to determine if vesicular-arbuscular (VA) mycorrhizal fungi are associated with the roots of common plant species found in North Carolina salt marshes. Root samples of Spartina alterniflora, S. patents, S. cynosuroides, Distichlis spicata, and Juncus roemerianus were collected from eight salt marsh sites. With the exception of S. alterniflora, all plant species were mycorrhizal. A greenhouse experiment was conducted to determine whether unfavorable soil conditions or inherent resistance by the plant inhibited development of mycorrhizal infection in field-collected S. alterniflora. Spartina alterniflora and S. patens were grown from seeds in soil collected from a pure stand of S. alterniflora (soil A) or a mixed stand of S. patens and D. spicata (soil P). Seedlings were harvested weekly for 8 wk, and roots were evaluated for infection by mycorrhizal fungi. Seedlings of S. patens were infected when grown for 2 wk in either soil A or soil P, indicating that soil collected from stands of S. alterniflora did not inhibit mycorrhizal infection in a susceptible host. Percent root length infected in S. patens was always greater in soil P than in soil A. Seedlings of S. alterniflora were not infected by mycorrhizal fungi in either soil A or soil P. Results of the greenhouse study indicate that S. alterniflora may be resistant to infection by vesicular-arbuscular mycorrhizal fungi.

In 78 patients we studied retrospectively the occurrence of occlusion in unilateral renal artery stenosis during antihypertensive drug treatment. Complete occlusion occurred in 14 patients (18%). In a multivariate analysis the following characteristics were included: blood pressure, aetiology of the stenosis, serum creatinine, the degree of the stenosis, anti-hypertensive medication, standing renal vein renin ratio and age. In this analysis the combination of a diuretic and an ACE-inhibitor, during the observation period, showed an independent relation to the development of an occlusion (P less than 0.05). Also the ACE-inhibitor alone showed a relation (P = 0.06). In the 14 patients who developed an occlusion only three showed a significant rise in serum creatinine. We conclude that special attention should be given to the follow-up of patients with renal artery stenosis who have ACE-inhibitors in their treatment regimen, especially when in combination with a diuretic.

Dexamethasone-modified adrenal scintigrams were performed on 13 patients with an aldosterone-producing adenoma and on one patient with an aldosterone-producing carcinoma. Adrenal scintigrams using 131I-19-Iodocholesterol were obtained after short pre-treatment with dexamethasone, while 131I-6 beta-Iodomethyl-19-Nor-Cholesterol scintigrams were performed after long-term pre-treatment with dexamethasone during 9-21 days. Using the former procedure the adrenal scintigrams correctly identified the adenoma in 3 of 8 patients, while with the latter procedure the adrenal scintigrams localized the adenomas in 8 out of 9 patients, including 3 patients in whom the former procedure had failed. The adrenal carcinoma was not visualized with 131I-6 beta-Iodomethyl-19-Nor-Cholesterol. Thus, the sensitivity of 131I-19-Iodocholesterol scintigrams to detect aldosterone-producing adenomas was only 37.5%. Uptake of radioactivity in the normal contralateral adrenal gland accounted for the low detection rate. On the other hand, the 131I-6 beta-Iodomethyl-19-Nor-Cholesterol scintigrams, performed after long-term pre-treatment with dexamethasone, had a sensitivity of 89%. It is suggested that long-term pre-treatment with dexamethasone contributed to the improved sensitivity by a more effective suppression of radioactivity uptake in the normal adrenal gland.

In a group of 269 untreated hypertensive patients the effect of a single oral dose of captopril (25 mg) on blood pressure was studied for 90-120 minutes. The systolic blood pressure decreased by more than 20% in 9.5% and by more than 30% in 1.1% of the patients. In 22.6% the diastolic blood pressure decreased by more than 20%; in 4.5% it fell more than 30%. The calculated mean arterial pressure (MAP) was reduced by more than 20% in 12.3% of the patients and by more than 30% in 3%. Three patients showed transient neurological deficits. Factors related to a strong blood pressure drop were: renal artery disease and resistant hypertension. However, a potentially dangerous fall in blood pressure, i.e. an acute fall of MAP of over 30%, was also observed in the absence of these risk factors. Therefore not all patients at risk can be identified in advance, and treatment with ACE-inhibitors has to be started under well-controlled circumstances especially in elderly patients.

It has been known for several years that blood pressure in the elderly may fall after a meal. Although the mechanism is not fully understood, postprandial blood pressure reduction seems to be related to glucose related factors, since blood pressure only falls after oral glucose loading, but not after oral fructose, fat or protein loading. Vasoactive gastrointestinal hormones may play a role in the glucose induced vasodilation of splanchnic vasculature, but attempts to identify such hormones were unsuccessful. Therefore we suggest that interference of insulin with a sympathetic response diminished by age or disease to splanchnic vasodilation, may be responsible for the postprandial fall in blood pressure in the elderly. However, vasodilator effects of insulin or a baroreflex response diminished by insulin do not seem to be involved. Although the clinical significance of postprandial blood pressure reduction remains uncertain, several advises can been given. Treatment of hypertension, small carbohydrate meals, use of caffeine before a meal or treatment with the somatostatin analogue SMS 201-995 may have a beneficial effect.

Tree thinking refers to an approach to evolution education that emphasizes reading and interpreting phylogenetic trees. We studied the relationship between introductory biology students’ tree-thinking ability and their acceptance of evolutionary theory. Comparisons between a semester in which interpretation of phylogenetic trees and related concepts were taught as stand-alone topics versus one in which tree thinking was used as an organizing framework for the course curriculum found significant increases in students’ ability to read and interpret trees in both semesters, but only in the tree thinking semester was there a significant increase in students’ scores on the Measure of the Acceptance of the Theory of Evolution (MATE) instrument. Over four additional semesters, the Tree Thinking Concept Inventory (TTCI) was used to assess students’ tree-thinking abilities before and after the course. We found that MATE posttest scores correlated with gains in tree-thinking ability. These increases in MATE posttest scores were predominantly due to students’ reporting greater acceptance of the scientific evidence supporting evolutionary theory. Increased acceptance of evolution in a tree-thinking versus non-tree-thinking semester and significant positive correlations between TTCI and MATE scores indicate there is a relationship between tree-thinking ability and acceptance of evolution. This result suggests that, as a framework to connect different forms of data and investigate a variety of biological phenomena, tree thinking can promote greater acceptance of the evidence and scientific validity of evolutionary theory in introductory biology students.

Contains fulltext : 50233.pdf (Publisher’s version ) (Closed access) BACKGROUND: Vitamin B-12 deficiency is associated with cognitive impairment in older people. However, evidence from randomized trials of the effects of vitamin B-12 supplementation on cognitive function is limited and inconclusive. OBJECTIVE: The objective was to investigate whether daily supplementation with high doses of oral vitamin B-12 alone or in combination with folic acid has any beneficial effects on cognitive function in persons aged >/=70 y with mild vitamin B-12 deficiency. DESIGN: In a double-blind, placebo-controlled trial, 195 subjects were randomly assigned to receive 1000 microg vitamin B-12, 1000 microg vitamin B-12 + 400 microg folic acid, or placebo for 24 wk. Vitamin B-12 status was assessed on the basis of methylmalonic acid, total homocysteine (tHcy), and holotranscobalamin (holoTC) concentrations before and after 12 and 24 wk of treatment. Cognitive function was assessed before and after 24 wk of treatment with the use of an extensive neuropsychologic test battery that included the domains of attention, construction, sensomotor speed, memory, and executive function. RESULTS: Vitamin B-12 status did not change significantly after treatment in the placebo group; however, oral vitamin B-12 supplementation corrected mild vitamin B-12 deficiency. Vitamin B-12 + folic acid supplementation increased red blood cell folate concentrations and decreased tHcy concentrations by 36%. Improvement in memory function was greater in the placebo group than in the group who received vitamin B-12 alone (P = 0.0036). Neither supplementation with vitamin B-12 alone nor that in combination with folic acid was accompanied by any improvement in other cognitive domains. CONCLUSION: Oral supplementation with vitamin B-12 alone or in combination with folic acid for 24 wk does not improve cognitive function.