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Biomedical subjects

K S Kristensen

Publications and source records attributed to K S Kristensen.

At least 19 recordsLinked to original sources
PubMed2003

White coat hypertension is a cardiovascular risk factor: a 10-year follow-up study.

The objective of this paper was to evaluate the cardiovascular risk in white coat hypertension (WCH). WCH is a well-known clinical entity defined by persistently elevated blood pressure (BP) in the doctor's office, whereas BP in other conditions is normal. The prognosis of WCH is unsettled, although two prospective studies that include normal control groups imply that the condition is benign. This study is a 10-year follow-up study on 420 patients with grade I-II hypertension newly diagnosed by their general practitioner and 146 normal controls (NTs). Ambulatory blood pressure (ABP) monitoring was performed at baseline. With our protocollated cutoff value of daytime-ABP <135/90 mmHg, 76 (18.1%) of the 420 hypertensives were white coat hypertensives (WCHs) and 344 were established hypertensives (EHs). With a lower cutoff of 135/85 mmHg, 40 (9.5%) were WCHs. Complete follow-up data were obtained for all 566 subjects. The mean duration of follow-up was 10.2 years (range 9.0-12.5). In the WCH group, 14 first events were recorded (18.4%) consisting of two cardiovascular deaths and 12 nonfatal cardiovascular events. In the EH group, the corresponding number of events were 56 first events (16.3%), 12 cardiovascular deaths and 44 nonfatal cardiovascular events, and in the NT group 10 first events (6.8%), two cardiovascular deaths and eight nonfatal cardiovascular events. The event rate was similar in the WCH group and the EH group and significantly lower in the NT group (P<0.05). When corrected for daytime-ABP, age and other confounders, the difference remained statistically significant. When using the lower cutoff of 135/85 mmHg, WCH was still associated with a significantly higher cardiovascular event rate. In conclusion, the main finding of this 10-year follow-up study is an increased cardiovascular risk in WCH compared to normotensive controls.

Adult↗
PubMed2001

Effect of different FSH isoforms on cyclic-AMP production by mouse cumulus-oocyte-complexes: a time course study.

The ability of different isoforms of follicle stimulating hormone (FSH) to induce accumulation of cAMP in cultured mouse cumulus-oocyte-complexes (COC) was evaluated in a time course study. Using isoform fractions representing less acidic (pI 6.43-5.69), mid-acidic (pI 5.62-4.96) and acidic (pI 4.69-3.75) isoforms, the accumulation of cAMP was monitored after an exposure time of 0, 5, 10, 15, 30, 60, 120 and 180 min. In addition, cAMP production was monitored for 0, 5, 10, 15 and 30 min following a 5 min exposure to FSH isoform fractions. Based on FSH measurements using radioimmunoassays, the less and mid-acidic isoforms caused almost twice as much cAMP to be accumulated than the acidic isoform fraction, thereby confirming an enhanced biological activity of FSH isoforms with a isoelectric point (pI) of >5.0. For all isoform fractions, maximal accumulation of cAMP was achieved after 30 min of exposure, after which the production declined to background levels. After a 5 min exposure to isoform fractions, levels of cAMP were significantly higher in the less acidic isoform fractions, but after isoform removal, the decline in cAMP production to background levels followed a similar time course. The results demonstrate that FSH isoforms with a pI of >5.0 induced significant biological responses within a period of 30 min and that prolonged exposure caused attenuated signal transduction. The present results, set in the context of the pulsatile characteristics of FSH release from the pituitary and the reported half-life of less acidic isoforms of approximately 35 min, make it conceivable that isoforms with a pI >5.0 actually possess important physiological functions during the periovulatory period.

Animals↗
PubMed2001

No impact of blood pressure variability on microalbuminuria and left ventricular geometry: analysis of daytime variation, diurnal variation and 'white coat' effect.

OBJECTIVE: To investigate the influence of blood pressure variability on target organ involvement. METHODS: Using a cross-sectional study of a hypertension clinic at a district general hospital, 420 patients with newly diagnosed untreated essential hypertension referred on a consecutive basis from general practice and 146 normal subjects drawn at random from the Danish National Register underwent a variety of measurements which included: echocardiography with determination of left ventricular mass index and relative wall thickness and early morning urine albumin/creatinine ratio. Mean, standard deviation and coefficient of variation of automated clinic values; daytime, night-time and full 24-h period were extracted from 24-h ambulatory blood pressure (ABP) monitoring. 'White coat' effect and dip were calculated. Hypertensives were classified into subjects with high or low variability, into 'white coat' hypertensives or established hypertensives and into dippers or non-dippers. RESULTS: Standard deviation of daytime blood pressure (BP) was positively associated with target organ damage and BP level, which was not the case when variability was expressed as a coefficient of variation. Patients with high variability exhibited no more significant target organ damage than patients with low variability, but patients with established hypertension had significantly more target organ damage than the 'white coat' hypertensives. The 'white coat' effect as such was not associated with increased target organ involvement. Non-dippers had significantly more cardiac target organ damage than dippers, but the difference disappeared after correction for different 24-h BP level. CONCLUSION: BP variability data obtained by non-invasive ABP monitoring does not seem to improve the information inherent in the BP level.

Adult↗
PubMed2000

Effect of inhibition of sterol delta 14-reductase on accumulation of meiosis-activating sterol and meiotic resumption in cumulus-enclosed mouse oocytes in vitro.

Two sterols of the cholesterol biosynthetic pathway induce resumption of meiosis in mouse oocytes in vitro. The sterols, termed meiosis-activating sterols (MAS), have been isolated from human follicular fluid (FF-MAS, 4,4-dimethyl-5 alpha-cholest-8,14,24-triene-3 beta-ol) and from bull testicular tissue (T-MAS, 4,4-dimethyl-5 alpha-cholest-8,24-diene-3 beta-ol). FF-MAS is the first intermediate in the cholesterol biosynthesis from lanosterol and is converted to T-MAS by sterol delta 14-reductase. An inhibitor of delta 7-reductase and delta 14 reductase, AY9944-A-7, causes cells with a constitutive cholesterol biosynthesis to accumulate FF-MAS and possibly other intermediates between lanosterol and cholesterol. The aim of the present study was to evaluate whether AY9944-A-7 added to cultures of cumulus-oocyte complexes (COC) from mice resulted in accumulation of MAS and meiotic maturation. AY9944-A-7 stimulated dose dependently (5-25 mumol l-1) COC to resume meiosis when cultured for 22 h in alpha minimal essential medium (alpha-MEM) containing 4 mmol hypoxanthine l-1, a natural inhibitor of meiotic maturation. In contrast, naked oocytes were not induced to resume meiosis by AY9944-A-7. When cumulus cells were separated from their oocytes and co-cultured, AY9944-A-7 did not affect resumption of meiosis, indicating that intact oocyte-cumulus cell connections are important for AY9944-A-7 to exert its effect on meiosis. Cultures of COC with 10 mumol AY9944-A-7 l-1 in the presence of [3H]mevalonic acid, a natural precursor for steroid synthesis, resulted in accumulation of labelled FF-MAS, which had an 11-fold greater amount of radioactivity incorporated per COC compared with the control culture without AY9944-A-7. In contrast, incorporation of radioactivity into the cholesterol fraction was reduced 30-fold in extracts from the same oocytes. The present findings demonstrate for the first time that COC can synthesize cholesterol from mevalonate and accumulate FF-MAS in the presence of AY9944-A-7. Furthermore, AY9944-A-7 stimulated meiotic maturation dose dependently, indicating that FF-MAS, and possibly other sterol intermediates of the cholesterol synthesis pathway, play a central role in stimulating mouse oocytes to resume meiosis. The results also indicate that oocytes may not synthesize steroids from mevalonate.

Animals↗
PubMed1999

White coat hypertension and blood pressure variability.

The objective of this cross-sectional study was to investigate blood pressure variability and pulse pressure in white coat hypertensives in comparison to established hypertensives and normal subjects. Four hundred and twenty patients were referred consecutively from general practice with newly diagnosed untreated essential hypertension. One hundred and forty-six control subjects were drawn at random from the Danish national register. Seventy-six patients from the former group were considered white coat hypertensive using a normalcy cutoff level of 135/90 mm Hg. Mean, standard deviation, and coefficient of variation of the blood pressures from the automated clinic readings, daytime, nighttime, and full 24-h periods were extracted from 24-h ambulatory blood pressure monitorings. Mean arterial pressure, pulse pressure, white coat effect, and dip were calculated in all three groups of subjects. The main findings were that white coat hypertensives did not differ significantly from normotensives regarding variability data except for the white coat effect. However, the white coat hypertensives had a significantly lower pulse pressure than the established hypertensives, according to clinic blood pressure and ambulatory readings. We conclude that white coat hypertension evaluated with indirect ambulatory blood pressure monitoring is not a state with a generally higher blood pressure variability than normotension or established hypertension. The patients with white coat hypertension have pulse pressure at the same level as normal controls, but significantly lower than established hypertensives.

Adult↗
PubMed1998

White coat hypertension and target organ involvement: the impact of different cut-off levels on albuminuria and left ventricular mass and geometry.

The aim of this cross-sectional study which took place in a hypertension clinic at a district general hospital in Denmark was to make a pragmatic definition of white coat hypertension. A total of 420 patients were referred consecutively from general practice with newly diagnosed untreated essential hypertension and 146 normal subjects were drawn at random from the Danish national register. The following measurements were taken: office blood pressure; 24-h ambulatory blood pressure (BP) monitoring; echocardiography with determination of left ventricular mass index and relative wall thickness; and early morning urine albumin/creatinine ratios. Four different cut-off levels were studied. An ambulatory daytime BP of 135.6/90.4 mm Hg was found to correspond to an office BP of 140/90 mm Hg in normal controls; used as a cut-off level in patients with newly diagnosed hypertension it separated 19% as white coat hypertensives. The end-organ involvement of these white coat hypertensives differed significantly from those with established hypertension but not from the normal controls. Lower cut-off levels were less efficient in this respect, as was the case when the systolic BP was not taken into account. In conclusion a pragmatic definition of white coat hypertension should--apart from well-established hypertensive office measurements--include a cut-off level close to 135/90 mm Hg ambulatory daytime BP.

Adult↗
PubMed1998

The in vivo and in vitro effects of rhG-CSF on allergic, haematological and biochemical variables.

UNLABELLED: The objective was to evaluate the influence of treatment with rhG-CSF on allergic indexes. This was done by open trial of 5 days' treatment with rhG-CSF (5 microg/kg/day s. c.). 10 patients (6 men), aged 28 to 54 years, with rhinoconjunctivitis due to grass pollen allergy, participated in the investigation. Main measures were blood count, basophil histamine release, skin test and conjunctival provocation test. RESULTS: The treatment resulted in significant increases in numbers of neutrophils (590%), basophils (280%), eosinophils (250%) and lymphocytes (71%). Total blood histamine was increased, but basophil histamine releasability was decreased. Serum alkaline phosphatase increased 92% and serum lactate dehydrogenase increased 35% (both significant). There were no significant changes in the skin tests and the conjunctival provocation tests. Two months after the treatment all tests had returned to baseline levels. Five of the patients (50%) reported side effects, one withdrew. In conclusion treatment with rhG-CSF increases the number of circulating blood cells other than neutrophils without causing changes in indexes of allergic reactivity.

Administration, Cutaneous↗
PubMed1995

[Albuminuria in persons with real hypertension, white coat hypertension and normotension].

A prospective comparison of office blood pressure, daytime ambulatory blood pressure and urinary albumin excretion was performed in 284 consecutive patients from general practice with newly diagnosed, untreated mild to moderate hypertension. Based on daytime ambulatory blood pressure 173 were classified as established hypertensives and 111 as white coat hypertensives. A sample of 127 subjects drawn from the Danish national register served as a normotensive control group. It was found that urinary albumin/creatinine ratio differed significantly between the three groups; the difference remained significant after correction for covariables. Early morning urine albumin/creatinine ratio was weakly but significantly correlated to blood pressure. Early morning urine albumin/creatinine ratio was as reproducible a measure as 24-hour albumin excretion. It is concluded that white coat hypertensive patients have less renal involvement than patients with established hypertension, but more than a normotensive control group.

Adult↗
PubMed1994

Increased numbers of circulating basophils with decreased releasability after administration of rhG-CSF to allergic patients.

Preliminary studies in hematological patients have indicated that treatment with rhG-CSF reduces basophil releasability ex vivo. We examined this phenomenon further, in allergic patients. Ten patients with grass pollen rhinoconjunctivitis were given rhG-CSF (5 micrograms/kg/day s.c.) for 5 days, and examined before and after treatment. Basophil counts increased from 5 to 19 x 10(9)/l (P < 0.01). Total blood histamine increased from 80 to 160 micrograms/l (P < 0.01), corresponding to a decrease in average basophil histamine content from 1.5 to 0.81 pg/cell (P < 0.01). Isolated mononuclear cells showed a significantly decreased histamine release (HR) when stimulated with A23187 and grass. Whole blood experiments showed a similar decreased HR to grass and anti-IgE (P < 0.01). However, we found an increase in total blood histamine. We conclude that treatment with rhG-CSF (1) increases the number of circulating blood basophils, (2) reduces the average histamine content per basophil, and (3) reduces the basophil releasability. These findings could be due to the mobilization of immature basophils from the bone marrow.

Adult↗
PubMed1994

Microalbuminuria in 411 untreated individuals with established hypertension, white coat hypertension, and normotension.

We compared urinary albumin excretion in normotensive subjects and patients with white coat and established hypertension. The study involved prospective comparison of office blood pressure, daytime ambulatory blood pressure, and urinary albumin excretion in consecutive patients (n = 284) who were selected from general practice with newly diagnosed mild to moderate hypertension before the institution of pharmacologic antihypertensive therapy. All patients had a diastolic office blood pressure above 90 mm Hg; 173 had a consistently elevated diastolic blood pressure (established hypertension), and 111 had an average daytime ambulatory blood pressure below 90 mm Hg (white coat hypertension). A sample of 127 subjects drawn from the Danish national register served as a normotensive control group. The main outcome measure was the ratio of early morning urinary albumin to creatinine. This ratio differed significantly among the three groups, being (on a molar basis) 21 +/- 69 x 10(-6) in the normotensive subjects, 22 +/- 39 x 10(-6) in the white coat hypertensive patients, and 51 +/- 177 x 10(-6) in patients with established hypertension. The difference remained significant after correction for covariables. The ratio of early morning urinary albumin to creatinine was weakly but significantly correlated to blood pressure, was more pronounced for ambulatory than for office measurements, was more pronounced for systolic than for diastolic pressure, and was more pronounced for hypertensive than for normotensive individuals. The ratio was as reproducible a measure as 24-hour albumin excretion. We conclude that white coat hypertensive patients have less renal involvement than patients with established hypertension but more than a normotensive control group.

Adult↗
PubMed1993

Left ventricular mass and geometry in patients with established hypertension and white coat hypertension.

This study was designed to compare the cardiac mass and geometry in white coat hypertensive patients and established hypertensive patients through the prospective comparison of office blood pressure, daytime ambulatory blood pressure, and echocardiographically determined left ventricular mass and cardiac geometry in consecutive patients. We studied 143 patients from general practice in an outpatient hypertension unit. The patients had newly diagnosed mild-to-moderate hypertension prior to the institution of pharmacological anti-hypertensive therapy. All patients had a diastolic office blood pressure above 90 mm Hg; 90 had a consistently elevated diastolic blood pressure (established hypertension), whereas 53 had an average daytime ambulatory blood pressure below 90 mm Hg (white coat hypertension). Left ventricular mass index was significantly higher in the group with established hypertension, 102.4 +/- 26.6 g/m2 (mean +/- SD) v 93.6 +/- 23.5 (P = .045). Relative wall thickness was likewise significantly higher, 0.36 +/- 0.07 v 0.33 +/- 0.06 (P = .004). There was no significant difference in left atrial dimension. In a multiple regression model the ambulatory measurements and not the office measurements were statistically significantly associated with the extent of cardiac hypertrophy. Further, 44/53 (83%) of the patients with white coat hypertension had normal left ventricular dimensions, versus only 55/90 (61%) of the patients with established hypertension (P = .033). Thus, white coat hypertensive patients display less cardiac involvement than patients with established hypertension, indicating that they should rather be treated as normotensives than as hypertensives, ie, not with pharmacological antihypertensive therapy.

Adult↗
PubMed1993

Histamine-releasing serum factors as a predictor of the outcome of insect sting reactions. Results from a multicentre study.

Cord blood cells were incubated (passively sensitized) with sera from 27 patients with previous systemic reactions to insect stings. Histamine release (HR) from these cells was measured following exposure to venom extracts at increasing concentrations. The aim was to see whether this parameter could predict more efficiently than RAST and skin test the outcome of a subsequent re-sting. Results showed that HR from passively sensitized cells tended to reflect skin sensitivity and specific IgE levels. If patients were not re-stung during the follow-up period, HR from the passively sensitized cells frequently decreased whereas an increase was seen (in 6/13) when using sera collected after re-sting. In conclusion HR from passively sensitized cord blood cells could not satisfactorily predict re-sting reactions in the serum donors.

Fetal Blood↗
PubMed1992

[What do we know about consultation hypertension?].

This review article examines the essential literature concerning "white coat" hypertension. It is stated that "white coat" hypertension is present in approximately 20% of patients with diagnosed mild to moderate hypertension. It is concluded that the pathophysiology of "white coat" hypertension is incompletely investigated; that the prognosis for untreated "white coat" hypertension seems fair; medical treatment being scarcely required. It is concluded further that more accurate diagnosis of mild to moderate hypertension, including the use of ambulatory blood pressure monitoring, will reduce the overall expenses by approximately million Danish crowns annually (approximately 2,000,000 pounds).

Denmark↗
PubMed1992

[Patients' knowledge about their own medication--does verbal information help? A blind, randomized study].

Patient's knowledge about their own medicine is often insufficient, and this is possibly a contributory factor for noncompliance. We interviewed 65 patients (median age 61 years) from an out-patient clinic with free access and 86 patients (median age 68 years) from a hospital outpatient clinic. In both groups, knowledge about the dosage and the adverse effects of the drugs was poor. Old age and polypharmacy were associated with poor knowledge; there were no differences as regards knowledge between the two out-patient clinics. The 86 patients from the hospitals out-patient clinic were randomised to either 30 minutes of extended verbal information or to the standard information of the department. At the subsequent visit eight weeks later, a repeated interview indicated, that the informed group had generally improved knowledge about their own medication, while this was not the case in the control group. A statistically significant difference between the groups was, however, only found for medication knowledge about side effects. It is concluded that out-patients knowledge about their own medication is often poor, but can be improved by verbal information.

Adult↗