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Biomedical subjects

D Klaus

Publications and source records attributed to D Klaus.

At least 19 recordsLinked to original sources
PubMed2002

Effects of space flight, clinorotation, and centrifugation on the substrate utilization efficiency of E. coli.

Cultures of Escherichia coli grown in space reached a 25% higher average final cell population than those in comparably matched ground controls (p<0.05). However, both groups consumed the same quantity of glucose, which suggests that space flight not only stimulated bacterial growth as has been previously reported, but also resulted in a 25% more efficient utilization of the available nutrients. Supporting experiments performed in "simulated weightlessness" under clinorotation produced similar trends of increased growth and efficiency, but to a lesser extent in absolute values. These experiments resulted in increases of 12% and 9% in average final cell population (p<0.05), while the efficiency of substrate utilization improved by 6% and 9% relative to static controls (p=0.12 and p<0.05, respectively). In contrast, hypergravity, produced by centrifugation, predictably resulted in the opposite effect--a decrease of 33% to 40% in final cell numbers with corresponding 29% to 40% lower net growth efficiencies (p<0.01). Collectively, these findings support the hypothesis that the increased bacterial growth observed in weightlessness is a result of reduced extracellular mass transport that occurs in the absence of sedimentation and buoyancy-driven convection, which consequently also improves substrate utilization efficiency in suspended cultures.

Biological Transport↗
PubMed2000

Underutilizers of mammography screening today: characteristics of women planning, undecided about, and not planning a mammogram.

Using concepts from the Precaution Adoption Process Model, we identified behavioral factors, sociodemographic and psychosocial variables, and beliefs about breast cancer that discriminated among women at different stages with regard to their intention to obtain mammography screening. An independent survey company conducted telephone interviews with 2,507 women aged 50 to 80 who were identified as underutilizers of mammography screening. Each underutilizer was assigned to one of three stages with regard to intention to get a mammogram: (a) definitely planning, (b) thinking about, and (c) not planning. Estimated actual risk of breast cancer, perceived risk to breast cancer, worry about breast cancer, and fear of learning from a mammogram that one has breast cancer were variables found to be significantly associated with intention to obtain a mammogram for several subgroups of underutilizing women. There are significant behavioral and psychosocial variables, beliefs and feelings about breast cancer, and demographic characteristics that distinguish underutilizing women at various stages with regard to intention to obtain mammography screening. Our findings provide new information that could help the health care professional motivate women who are not planning to utilize this preventive health measure to become regular utilizers.

Aged↗
PubMed1996

Non-invasive oscillometric wrist and upper arm blood pressure measurements compared with invasive values.

In 100 patients invasive blood pressure (BP) measurements in the aortic arch were compared with oscillometric devices at the left upper arm (UA1, device: Hestia OZ 80) and at the left and right wrists (Wl, Wr, device: NAiS Blood Pressure Watch). BPs/BPd at Wl were on average 4.3/6.0 mmHg higher than aortic BP with a relative high variability. Difference between Wls and Aos more than +/- 20 mmHg in 16% of patients between Wld and Aod more than +/- 20 mmHg in 5% of patients. Within the limits of +/- 10 mmHg, we found 56% of the systolic and 74% of the diastolic wrist values compared to the aorta. The automatic oscillometric BP measurement at the wrist is a useful method for BP self-measurement, but should be compared with upper arm values before recommending it (difference < +/- 10 mmHg) in the individual case.

Adult↗
PubMed1995

[Treatment of hypertension with a fixed calcium antagonist-diuretic combination. Observations from treatment of 5,595 patients].

METHOD: In an observational study lasting 6 months, 5,595 patients with essential hypertension were treated with a combination of a calcium antagonist and a diuretic, with the aim of testing the efficacy and safety of the drug. Some 63.8% oft the patients had already received anti-hypertensive treatment; 67.3% of the patients also had accompanying diseases. Treatment was begun with a single daily tablet comprising 160 mg verapamil, 50 mg triamterene and 25 mg hydrochlorothiazide (Veratide), and the dose could be reduced to one-half or increased to two daily as indicted by the response of the blood pressure. RESULTS: At the end of 6 months of treatment, the overall groups showed a decrease in both systolic and diastolic blood pressure of 15.2% (26/15 mmHg). Breakdown oft the patients into various age groups revealed no differences in the results. Responder rates varied between 62.0 and 71.8%. Among patients with isolated systolic hypertension, the response rate was 66.4%. In this form of hypertension only the systolic blood pressure was lowered. During the course of treatment, 6.8% of the patients developed side effects, which were severe in 0.9% of the cases. In only 143 of the 5,595 patients did the treatment have to be broken off. CONCLUSIONS: The efficacy and safety oft the combination preparation investigated have been confirmed under doctor's office conditions. The decrease in diastolic blood pressure was more marked among smokers than among non-smokers.

Adult↗
PubMed1995

In-vivo investigation of material quality of bone tissue by measuring apparent phalangeal ultrasound transmission velocity.

The square of ultrasound transmission velocity in a material is related to the modulus of elasticity, which is known to be an indicator of stability in bone. The aim of our study was to use ultrasound transmission velocity to obtain information about the material properties of bone tissue, keeping other factors possibly influencing ultrasound transmission as constant as possible. Apparent phalangeal ultrasound transmission velocity (APU) measured in 54 isolated, fresh pig phalanges was shown to be independent of bone mineral density (BMD) measured by SPA. Fastest sound transmission led exclusively through cortical bone so that intertrabecular connectivity in spongious bone could not influence the result. In humans APU was measured in the mediolateral direction at the midphalanx of the middle finger. In 53 healthy subjects (15-81 years old; 27 women, 26 men), there was a decrease of APU with age (r = -0.30, p < 0.05). Further, when comparing the results of both hands intraindividually almost identical values indicated constant intraindividual architecture of bone at this location. There was no evidence for a relation of APU to physical load comparing dominant and nondominant hand and relating the results to subjectively estimated physical load. In a second group of 43 perimenopausal women (47-60 years old), APU, which again decreased with age (r = -0.33, p < 0.05), was found not to be correlated to BMD measured by SPA at the distal forearm (cortical bone).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

[Comparison of invasive blood pressure measurement in the aorta with indirect oscillometric blood pressure measurement at the wrist and forearm].

Indirectly measured blood pressure at the wrist or upper arm was compared with directly measured values in the aortic arch during routinely performed diagnostic cardiac catheterization in 100 patients (31-80 years, mean 59.3 years, 60% males). The noninvasive measurements were carried out by oscillometric devices, NAiS Blood Pressure Watch for measurements at the wrist, and Hestia OZ80 at the upper arm. Systolic blood pressure measured at the wrist was 4.3 +/- 14.1 mm Hg, and the diastolic value 6.0 +/- 8.9 mm Hg higher than when measured at the aortic arch; the difference was significant in both cases. Correlation coefficients were 0.85 for systolic and 0.71 for diastolic blood pressure. In 16% of the patients the systolic blood pressure at the wrist differed more than +/- 20 mm Hg. The diastolic blood pressure at the wrist measured more than +/- 20 mm Hg higher than in the aorta in 5% of the patients. At the upper arm mean systolic values were not different to the aorta. The diastolic pressure was 9.3 +/- 9.8 mm Hg higher in the aorta than at the upper arm. To verify the accuracy of values measured with the NAiS Blood Pressure Watch compared with the standard technique at the upper arm, sequential measurements were made at wrist and ipsilateral upper arm in the same group of 100 patients. The systolic blood pressure at the left wrist was 3.4 +/- 13.3 mm Hg higher and the diastolic pressure 3.8 +/- 9.5 mm Hg lower than at the upper arm. Only 53% of systolic values lay within a range of +/- 10 mm Hg. The correspondence between wrist and upper arm values was better for diastolic blood pressure, the values differing by less than +/- 10 mm Hg in two-thirds of patients. Self-measurement of arterial blood pressure with an oscillometric device at the wrist can be recommended only in individual cases with a difference of simultaneously measured values at the upper arm of less than +/- 10 mm Hg for systolic and diastolic blood pressures. The standard method for indirectly measuring arterial blood pressure remains the measurement at the upper arm site, which nevertheless showed a systolic pseudohypertension (deviation of more than 10 mm Hg) in comparison to the invasively measured values in 15% of our selected patients and a diastolic pseudohypertension (deviation of more than 15 mm Hg) in 23% of the patients.

Adult↗
PubMed1993

[The value of diuretics in monotherapy of hypertension].

AIM: To represent the usefulness of thiazide diuretics as monotherapy of primary hypertension. MAIN POINTS: Moderate doses of thiazide diuretics can produce a reduction in blood pressure equal to that of beta blockers, calcium antagonists and ACE inhibitors, and achieve an equally high response rate. The advantages and disadvantages of the specific action profile of these diuretics are described. Discussions about the reduction in cardiovascular mortality is represented and practical conclusions drawn. The specific indications for monotherapy with thiazide diuretics include systolic, diastolic and isolated systolic hypertension in the elderly hypertensive, and hypertension in NYHA III and IV cardiac insufficiency. Suggestions for their use in practice are given.

Antihypertensive Agents↗
PubMed1992

Regression of left ventricular hypertrophy during long-term antihypertensive treatment--a comparison between felodipine and the combination of felodipine and metoprolol.

Seventy-six hypertensive patients with left ventricular hypertrophy (LVH) were randomized to receive felodipine or felodipine plus metoprolol in a double-blind parallel-group study. The doses of each treatment regimen were titrated to obtain a diastolic blood pressure (BP) of less than 95 mmHg. The duration of the treatment was 9 months. At the end of the study, BP was significantly reduced in both groups, and the reduction did not differ between the groups. Left ventricular posterior wall and septum thickness were significantly and similarly reduced in both groups. Left ventricular systolic and diastolic end diameters were not significantly changed. Left ventricular mass (LVM) was significantly and similarly reduced in both treatment groups, as was the ratio of LVM and left ventricular end diastolic volume. In conclusion, felodipine and the combination of felodipine and metoprolol reduced left ventricular hypertrophy to the same extent when BP was similarly reduced.

Adult↗
PubMed1992

The role of calcium antagonists in the treatment of hypertension.

Calcium antagonists are of particular importance in the treatment of hypertension because they influence the free cytoplasmic calcium concentration and thereby many pressor mechanisms in the smooth muscle cell. A fall in the peripheral resistance is the main hemodynamic effect, and this is more marked with the second-generation calcium antagonists because they are more vasoselective than the first calcium-channel blockers. Particularly important is their lack of effect on lipid and glucose metabolism, as well as the absence of serious side effects. It has not yet been possible to confirm that the antiatherogenic effect found in some animal models also occurs in humans. Calcium antagonists are effective, safe, and well-tolerated antihypertensive agents that can be combined with all other antihypertensives with the exception of the combination of verapamil and a beta-blocker. They are easy to dose for individualized "stepped" therapy. They have a particular role in hypertensive patients with cardiac effects secondary to hypertension, coronary artery disease, obstructive bronchial diseases, diabetes, renal disease, and peripheral arterial occlusive disease.

Animals↗
PubMed1991

Low-dose nitrendipine in mild hypertension: a double-blind, placebo-controlled, comparative study.

The objective of this study was to determine whether 10 mg of nitrendipine once daily is adequate for treatment of mild hypertension. The study was a randomized, double-blind, multicenter, and placebo-controlled group comparison over 8 weeks (a 2-week placebo-controlled washout phase followed by a 6-week treatment phase) with measurement of blood pressure, routine laboratory tests, compliance monitoring, and recording of side effects every 2 weeks. The study subjects were 141 outpatients with mild arterial hypertension and were given one 10-mg tablet of nitrendipine or placebo once daily. The end point used was reduction in diastolic blood pressure (DBP) by at least 10 mm Hg or to less than or equal to 90 mm Hg; the responder rate at the end of the treatment phase was determined. After 6 weeks of treatment, the mean reduction in DBP was 11.8 mm Hg under nitrendipine compared with 5 mm Hg under placebo. The responder rates were 73% (53 of 73 patients) in the nitrendipine group and 26% (18 of 68 patients) in the placebo group. This difference is statistically significant. Side effects were reported by a total of 14 patients (6 in the nitrendipine group, 8 in the placebo group). There was one dropout in each group. No changes in laboratory parameters were observed. In conclusion, nitrendipine is suitable for monotherapy of mild arterial hypertension in the dosage of 10 mg once daily used in this study.

Aged↗
PubMed1989

Management of hypertension in actively exercising patients. Implications for drug selection.

In general, rises in systolic blood pressure to over 200 mm Hg during exercise with a workload of 100W are regarded as pathological. Excessive exercise blood pressure values are to be expected in principle in all hypertensives. However, there are so far no generally accepted criteria for diagnosis of isolated systolic exercise hypertension (with normal values of resting blood pressure). The incidence of isolated systolic exercise hypertension is estimated to be about 10% of a selected population. In patients with excessive rises in blood pressure during exercise who want to engage actively in sport, general measures (reduction of obesity, restriction of alcohol and salt intake) and endurance training should be recommended initially. For endurance training, sporting activities that involve dynamic exercise are to be recommended (walking, running, mountain hiking, cycling, swimming, cross-country skiing). Activities involving isometric exercise (rowing, diving, tennis) and sport of a competitive nature are not suitable. In moderately severe and severe hypertension (diastolic blood pressure values in excess of 105 mm Hg), sporting activities and endurance training are contraindicated. If the exercise blood pressure values cannot be lowered below 220 mm Hg with the general measures mentioned, pharmacotherapy is to be considered. The drugs of choice for suppressing excessive rises in blood pressure during exercise are beta-blockers. In this group, beta 1-blockers are to be preferred to non-selective beta-blockers because of the metabolic neutrality of the former. beta-Blockers without intrinsic sympathomimetic activity (ISA) lower the blood pressure-pulse rate product more effectively than beta-blockers with ISA. Alternatively, calcium antagonists of the verapamil type and ACE inhibitors can be employed.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗