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Biomedical subjects

F T Jensen

Publications and source records attributed to F T Jensen.

At least 55 records · Page 3Linked to original sources
PubMed1988

Functional status and left ventricular performance late after valve replacement for aortic stenosis. Relation to preoperative data.

Relations between preoperative data and status at one- and 10-year control and left ventricular performance (radionuclide angiocardiography) at follow-up 10-17 years (mean 12 years) after valve replacement (1965-73) for aortic stenosis were studied. Marked improvements at one-year were noted for New York Heart Association (NYHA) functional classes, cardiothorac index (CTI), and ECG hypertrophy (Romhilt-Estes) score. One-year status did not influence that at 10 years. In 59 patients who were in NYHA class I at one year, class I was maintained in 75% of those who were in class II preoperatively, compared with 47% of those who had been in class III, and 23% of those who had been in class IV, (P less than 0.05). The same relation to preoperative level was found for patients with CTI less than or equal to 0.50 at one-year control. The ECG score did not change after the first year. Left ventricular hypertrophy (ECG score greater than or equal to 4) was present in 90% and 84% of the patients at one and 10 years, respectively. Ejection fraction (EF) and peak filling rate (PFR) at follow-up were (mean +/- SD) 65 +/- 13% and 3.14 +/- 1.05 end-diastolic volume s-1, respectively; only 13 patients had a radionuclide study within the normal range for all parameters measured. A normal study was found predominantly in patients with complete regression of hypertrophy. Multiple linear regression models incorporating preoperative data allowed calculation of predicted EF (65 +/- 9) and PFR (3.17 +/- 0.92) which did not differ from the measured values. Functional status and left ventricular systolic and diastolic performance late after the operation depended closely on preoperative status. Improvements noted at one year were only temporary in patients with preoperative advance disease. Normal left ventricular performance late after valve replacement was related to complete reversibility of hypertrophy. Our results argue for operation in minimally symptomatic patients.

Adult↗
PubMed1988

Aortic regurgitation after surgical relief of subvalvular membranous stenosis. A long-term follow-up study.

A postoperative follow-up study of 21 cases of discrete membranous subvalvular aortic stenosis is presented. The age at operation was 6-47 (mean 16) years, and the follow-up time 0.6-16 (mean 6.7) years. Preoperatively most patients were in NYHA function class II or III and had high peak systolic pressure gradient, left ventricular hypertrophy and/or cardiothoracic index greater than 0.50. At follow-up all but six patients were in NYHA class I, the Doppler-estimated peak systolic gradient was 0-36 (mean 18) mmHg, the cardiothoracic index unchanged and the mean left ventricular hypertrophy score had declined from 4.3 to 2.3. Of 13 patients without aortic regurgitation preoperatively, eight had regurgitation at follow-up (group I) and five did not (group II). The interval to follow-up was significantly longer and the preoperative peak systolic gradient was greater in group I than in group II. Aortic regurgitation may develop even after surgical relief of discrete membranous subvalvular aortic stenosis, possibly associated with high preoperative pressure gradient and time from operation. Regular postoperative Doppler echocardiography is therefore recommended.

Adolescent↗
PubMed1987

Bone turnover and balance evaluated by a combined calcium balance and 47calcium kinetic study and dynamic histomorphometry.

Bone resorption and formation rates were evaluated at the organ level using calcium kinetic methods and at the trabecular bone tissue level using dynamic histomorphometry in 20 patients with various metabolic bone diseases (primary hyperparathyroidism (N = 9), hyperthyroidism (N = 6), and hypothyroidism (N = 5). Highly significant correlations were demonstrated between resorption and formation rates at organ level (r = .90, P less than .001) and at tissue level (volume referent) (r = .93, P less than .001), indicating a high degree of coupling between resorption and formation within the three disease states. Tissue level resorption rates (surface referent, as well as volume referent) both correlated significantly (P less than .01) to organ level resorption rate (r = .60 and r = .63, respectively). Fractional active resorption surface and cellular level resorption rate did not reveal significant correlations to calcium kinetic estimates. No correlation could be demonstrated between organ level mineralization rate and formative or labeled trabecular surfaces. However, all tetracycline based tissue level formation rates revealed highly significant correlations (P less than .01) to organ level mineralization rate (calcification rate, r = .71; surface referent bone formation rate, r = .59; volume referent bone formation rate, r = .68). Based on histomorphometric parameters for resorption and formation, actual and predicted tissue level trabecular bone balances were calculated. Both the actual and predicted bone balance correlated significantly to the organ level calcium balance (P less than .05). Correction for skeletal size based on BMC measurements did not improve any of the correlations significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Left ventricular ejection fraction determined with the nuclear stethoscope, gamma camera and contrast ventriculography.

Left ventricular ejection fractions (EF) were measured with a nuclear stethoscope (NSt, beat-to-beat and ECG gated summation method) and contrast ventriculography (VG) immediately following one another (IFOA) (r X 0.96 and 0.95, respectively, n = 13). NSt and ECG gated gamma camera (MUGA) recordings IFOA were compared (r = 0.97 and 0.96, respectively, n = 23) as were non-IFOA recordings (r = 0.90 and 0.91, respectively, n = 13). Correlation between repeated NSt EF measurements gave: r = 0.91 (n = 22) for both methods. Paired NSt recordings in an invasive test situation (during invasive angiocardiography) and in a noninvasive situation (supine, 30 min of rest) gave for patients with EF less than 50 (mean +/- S.D.): EF invasive = 36 +/- 12, EF noninvasive = 41 +/- 13 (n = 4, p less than 0.05), and for patients with EF greater than or equal to 50: EF invasive = 59 +/- 7, EF noninvasive = 57 +/- 7 (n = 9, N.S.). The mean paired differences (EF noninvasive -EF invasive) in the low (less than 50) and high (greater than or equal to 50) EF range differed significantly: +5.3 versus -1.3, respectively (p less than 0.001). The recordings with the ECG-gated summation method gave similar results. The heart rate (beats min-1) in the noninvasive and invasive situation were (mean +/- S.D.): 68 +/- 11 and 78 +/- 16, respectively (p less than 0.01). We conclude that the patients were in a higher level of stress in the invasive situation. Accordingly ventricles with normal contractility (EF greater than or equal to 50) reacted with a slight increase in EF, and ventricles with compromised function (EF less than 50) reacted with a decrease in EF, compared to the values in the noninvasive situation. Incorporated in a correlation between MUGA and VG are, besides methodologically based differences, test-situation based systematical differences. Consequently the results of MUGA method should be given uncorrected. The results documents the accuracy and reliability of the NSt.

Adolescent↗
PubMed1986

Primary hyperparathyroidism: evaluated by 47calcium kinetics, calcium balance and serum bone-Gla-protein.

Combined 47Calcium kinetic and calcium balance studies with correction for dermal calcium loss were performed in thirteen patients with primary hyperparathyroidism (PHP), in whom serum bone-Gla-protein (S-BGP) was measured, and in ten matched controls. Dietary calcium was normal in PHP but both net (7.9 +/- 1.4 mmol Ca day-1 in PHP v. 3.5 +/- 0.9 mmol Ca day-1 in normals (mean +/- SE] and true (11.1 +/- 1.6 v. 6.8 +/- 0.9 mmol Ca day-1) intestinal absorbed calcium were enhanced (P less than 0.05). The renal calcium excretion (10.9 +/- 0.8 v. 5.1 +/- 0.4 mmol Ca day-1, P less than 0.001) and the dermal calcium loss (2.5 +/- 0.3 v. 1.5 +/- 0.1 mmol Ca day-1, P less than 0.02) were increased in PHP. Both patients and controls were in a negative calcium balance (P less than 0.01 and P less than 0.001, respectively) without any difference between the groups (P greater than 0.10). Mineralization (12.0 +/- 1.7 v. 4.8 +/- 0.8 mmol Ca day-1, P less than 0.02) and resorption rates (17.6 +/- 2.5 v. 7.9 +/- 0.6 mmol Ca day-1, P less than 0.02) were increased in PHP and S-BGP correlated positively to both variables (r = 0.64, P less than 0.05 and r = 0.62, P less than 0.05, respectively). Serum immunoreactive parathyroid hormone correlated positively to serum calcium (r = 0.69, P less than 0.01) but not to the calcium kinetic data.

Adult↗
PubMed1985

The effects of sodium fluoride, calcium phosphate, and vitamin D2 for one to two years on calcium and phosphorus metabolism in postmenopausal women with spinal crush fracture osteoporosis.

Calcium and phosphorus balances and 47Ca turnover studies were performed before and after 12-27 months of daily treatment with sodium fluoride (60 mg), calcium (30-45 mmol), phosphate (29-44 mmol), and vitamin D2 (18,000 IU) in 20 postmenopausal women with spinal crush fracture osteoporosis. Before treatment the mean calcium balance (-1.6 mmol Ca/day) was negative (P less than 0.05), whereas the mean phosphorus balance (-1.6 mmol P/day) did not differ from zero (P greater than 0.10). The treatment induced an increase in calcium absorption (P less than 0.01) with an unchanged renal excretion and dermal loss of calcium and an increase (P less than 0.02) in calcium balance, which became positive (P less than 0.01) (+3.3 mmol Ca/day). This enhancement in calcium balance was obtained by the combined effects of an increase (P less than 0.05) in bone mineralization rate and a decrease (P less than 0.05) in bone resorption rate. The observed increase in net phosphorus absorption (P less than 0.001) was more pronounced than the increase in renal excretion of phosphorus (P less than 0.001), and the phosphorus balance therefore increased (P less than 0.001) and became positive (P less than 0.001). A positive correlation was observed between net calcium and net phosphorus absorption (r = 0.065; (P less than 0.001) in the 32 studies where both calcium and phosphorus balance data were available. Furthermore, a positive correlation (r = 0.61; P less than 0.05) was found between the changes in net calcium and net phosphorus absorption during treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1985

Estimation of bone turnover evaluated by 47Ca-kinetics. Efficiency of serum bone gamma-carboxyglutamic acid-containing protein, serum alkaline phosphatase, and urinary hydroxyproline excretion.

Bone gamma-carboxyglutamic acid-containing (Gla) protein (BGP, osteocalcin) is a noncollagenous protein of bone present in plasma and removed by the kidney. Plasma BGP has been shown to be elevated in patients with certain bone diseases. The present study evaluates serum BGP (S-BGP), serum alkaline phosphatase (S-AP), and urinary hydroxyproline excretion (U-OHP) in diseases with differing bone turnover rates, and compares the accuracy of these measurements for estimating bone mineralization (m) and resorption (r) rates. S-BGP, S-AP, U-OHP, and creatinine clearance (Clcr) were measured in patients with primary hyperparathyroidism (n = 13), hyperthyroidism (n = 6), and hypothyroidism (n = 6). Bone mineralization and resorption rates were calculated from a 7-d combined calcium balance and 47Ca turnover study. A highly significant correlation (r = 0.69, P less than 0.001) was found between S-BGP and m. Multiple regression analysis disclosed a partial correlation between S-BGP and m when Clcr was taken into account (r = 0.82, P less than 0.001), and between S-BGP and Clcr when m was taken into account (r = -0.62, P less than 0.005). In accordance with this, a stronger correlation (r = 0.89, P less than 0.0001) was found between S-BGP X Clcr and m than between S-BGP and m. A less significant correlation was found between S-AP and m (r = 0.45, P less than 0.05). Furthermore, U-OHP showed a highly significant positive correlation to r (r = 0.78, P less than 0.001). Thus, in the studied disorders of calcium metabolism, individual serum levels of BGP depend on both mineralization rate and renal function. Serum levels of BGP corrected for alterations in renal function are superior to uncorrected S-BGP and to S-AP levels in the estimation of bone mineralization rates.

Adult↗
PubMed1985

The diagnosis of vesico-ureteral reflux. Radiologic and nuclear medicine methods.

Video voiding cystourethrography in 47 patients was compared to 99mTc cystography performed suprapubically in 20 patients and 123I Hippuran renocystography performed in 43 patients. The degrees of reflux were equally distributed through the grades. 99mTc cystography was negative in 4 of 5 grade 2 refluxes and positive in 4 out of 5 grade 3-4 refluxes. Computerized dynamic tracings of the 123I renocystography showed an activity level increase over the kidneys of more than 1% of the bladder activity level in 47 units, 18 were equivocal and 21 negative. Grade 2 and 3 reflux found on the video VCU was refound on the renocystography. 24 false positives were found. It is concluded that 99mTc cystography performed as in our unit adds no further information to the diagnosis of reflux and that 123I renocystography diagnosing the more severe degrees of reflux may be a future method of non-invasive reflux control.

Adolescent↗
PubMed1985

Regional CBF, intraventricular pressure, and cerebral metabolism in patients with ruptured intracranial aneurysms.

Regional cerebral blood flow (rCBF), cerebral metabolic rate of oxygen (CMRO2), intraventricular pressure, and lactate/pH levels in the cerebrospinal fluid (CSF) were measured in 38 patients with ruptured intracranial aneurysms between the 3rd and 13th day after subarachnoid hemorrhage (SAH). Angiography was performed following the rCBF study and the degree of vasospasm was measured on the angiograms. The patients were graded clinically according to the system of Hunt and Hess. Cerebral vasospasm significantly influenced rCBF: global reductions and focal changes (ischemia, hyperemia, and tissue peaks) were commonly associated with vasospasm. Patients with severe diffuse spasm always had global ischemia (21 +/- 5 ml/100 gm/min), and cerebral infarctions were demonstrated subsequently, The CMRO2 was more reduced than rCBF, indicating an uncoupling between flow and metabolism. This relative luxury perfusion was associated with CSF lactic acidosis and intracranial hypertension. The arteriovenous difference of oxygen was equally reduced in all categories of patients, probably due to the primary insult of SAH. The CMRO2 decreased concomitantly with arterial caliber, indicating a secondary impairment of cerebral metabolism due to vasospasm.

Adult↗
PubMed1985

Cerebrovascular reactivity in patients with ruptured intracranial aneurysms.

The cerebral vasomotor reactivity to arterial hypotension and hypocapnia was studied in 34 patients between the 3rd and 13th day after rupture of an intracranial saccular aneurysm. Using the intra-arterial xenon-133 injection method, regional cerebral blood flow (rCBF) and cerebral metabolic rate of oxygen (CMRO2) were measured. The intraventricular pressure and cerebrospinal fluid (CSF) lactate and pH levels were determined. The degree of vasospasm was measured on angiograms taken immediately following the rCBF study. The patients were graded clinically according to the system of Hunt and Hess. Cerebral autoregulation was intact in patients in good clinical condition, but was impaired in patients in poor clinical condition. There was a close correlation between the degree of vasospasm and the degree of autoregulatory impairment, which varied from focal disturbances to global impairment. Intracranial hypertension and CSF lactic acidosis were commonly found in association with vasoparalysis. Cerebrovascular response to hyperventilation was generally preserved, although often reduced. During hyperventilation, the cerebral perfusion pressure became elevated, and increases in CMRO2 were often found, even in patients with severe diffuse spasm and cerebral ischemia. The clinical significance of the results in relation to the treatment of delayed cerebral ischemia and to the use of intraoperative induced hypotension is discussed.

Adult↗
PubMed1984

Calcium metabolism evaluated by 47Ca kinetics. Methodologic aspects with optimization of a whole-body counter.

Optimization of a four-crystal stretcher geometry whole-body (WB) counter was performed. The measured geometric characteristic did not differ significantly from the theoretically calculated characteristic (p greater than 0.05). The linearity of the WB counter was high in the range 3.7 kBq to 3.7 MBq. Longtime variability of local background was CV = 3.7 per cent. In vivo sensitivity was calculated to 18 cpm/kBq and the detection limit to about 5 kBq. The reproducibility was estimated to 0.7 per cent. The WB counter was used in 47Ca turnover and calcium balance studies of 15 normal individuals. The data were analysed according to a modification of the expanding calcium pool model using an improved Bauer-Carlsson-Lindquist formulation. Variability and method errors of main parameters for calcium metabolism were evaluated.

Adult↗
PubMed1984

Treatment with high-dose oral vitamin D2 in patients with jejunoileal bypass for morbid obesity. Effects on calcium and magnesium metabolism, vitamin D metabolites, and faecal lag time.

Calcium and magnesium balance, 47Ca turnover studies, and measurements of vitamin D metabolites were performed before and after 7-10 months of vitamin D2 treatment (36,000 IU/day) in eight patients bypass-operated 3-6 years earlier for gross obesity. All patients had received a daily supplementation of calcium (27 mmol/day) since operation. Before treatment the net calcium absorption and calcium balance were normal compared with that of nine normal controls. Vitamin D metabolites were within normal limits. The endogenous faecal calcium level was increased and the faecal lag time shortened. Bone biopsies revealed osteomalacia in three of the patients. Vitamin D2 treatment induced an increase in calcium absorption and renal excretion of calcium, a reduced bone resorption rate, a more positive calcium balance, and healing of osteomalacia. Moreover, the vitamin D2 treatment induced a prolongation and normalization of faecal lag time, an increase in magnesium absorption, and a more positive magnesium balance. The effect might be mediated through 25-hydroxyvitamin D (25-OHD), which increased, whereas serum levels of 1,25-dihydroxyvitamin D (1,25-(OH)2D) and 24,25-dihydroxyvitamin D (24,25-(OH)2D) were unchanged. The results indicate that in some bypass-operated patients high-dose vitamin D2 has a beneficial effect on calcium and magnesium metabolism.

Adult↗
PubMed1984

Gallbladder emptying and gastrointestinal cyclic motor activity in humans.

UNLABELLED: The purpose of the present work was to answer two questions: does the human gallbladder empty in the fasting state, and, if so, is the emptying related to a specific phase of the activity in the gastrointestinal tract? The material consisted of nine healthy volunteers and the motility recordings were done with a perfused low-compliance system. Gallbladder emptying was recorded by the use of scintigraphy with 99mTc-HIDA. Eleven activity fronts were observed, and seven periods of gallbladder emptying were recorded. Reduction in counts over the gallbladder ranged from 8% to 32%. All emptyings took place in connection with phase-II activity in the intestine. Three were in close proximity to the following phase-III activity, and the other four occurred early in a phase II. Four activity fronts were not accompanied by output of bile. CONCLUSIONS: bile output from the gallbladder occurs in fasting humans, and gallbladder emptying takes place in connection with phase-II activity in the intestine but not always in close connection with the following phase-III activity.

Adult↗
PubMed1983

Calcium metabolism evaluated by 47Ca kinetics: estimation of dermal calcium loss.

Seventy-seven calcium balance and 47Ca turnover studies were performed in normal volunteers (n = 15) and in patients with osteoporosis (n = 12), primary hyperparathyroidism (n = 8), osteogenesis imperfecta (n = 5), medullary carcinoma of the thyroid (n = 4), thyrotoxicosis (n = 2) and intestinal bypass for obesity (n = 11). After intravenous injection of 20 microCi of 47Ca two retention curves of 47Ca were obtained: R1(t) directly measured on a whole-body counter and R2(t) calculated from the cumulated daily excretions of 47Ca in urine and faeces. The data were fitted to a modification of the continuously expanding exchangeable calcium pool model. Dermal calcium loss was estimated from the serum 47Ca specific radioactivity curve and the constantly increasing difference between the two retention curves. The median dermal calcium loss in 77 studies was 1.50 mmol 24 h-1 1.73 m-2 (range 0.13-4.60). The dermal calcium loss might be overestimated by redistribution of tracer or by eventual insufficient collection of urine and faeces. The possible influences of these errors have been evaluated. Patients with primary hyperparathyroidism had a greater (P less than 0.02) dermal calcium loss (2.64 mmol; range 0.80-4.50) than a control group (1.38 mmol; range 1.25-2.34).

Calcium↗
PubMed1983

Calcium metabolism evaluated by 47calcium-kinetics: a physiological model with correction for faecal lag time and estimation of dermal calcium loss.

Sixty-two calcium balance and 47Ca-turnover studies were performed in 51 individuals to evaluate the accuracy and the sensitivity of the methods. The data were analysed according to a modification of the expanding calcium pool model using an improved Bauer-Carlsson-Lindquist (BCL) formulation and an iterative computer procedure. A 7-day whole body retention curve (R1) combined with a retention curve constructed from excretion data alone (R2) was used to estimate dermal calcium loss (d) and to demonstrate the significance of individual corrections for delay in faecal excretion (faecal lag time = delta t). The mean d was 1.58 mmol Ca/day. The introduction of delta t improved the goodness of fit of the data to the model. delta t based on 47Ca-kinetics was superior to a fixed delta t of zero (P less than 0.01) or 2 days (P less than 0.05). The model derived renal calcium excretion rate was highly correlated (r = 0.98, P less than 0.001) to the chemical measured excretion rate. A similar highly significant correlation [RS = 0.78 (Spearman), P less than 0.001] was found between the model derived delta t and the carmine red delta t. These results indicate a high accuracy of the model. The directly measured parameters showed an excellent reproducibility with a coefficient of variation (CV) less than 4%. The reproducibility of the derived parameters was acceptable (CV = 10-20%) except for the balance (CV = 72%).

Adult↗
PubMed1982

Radioimmunoassay of calcitonin in unextracted human serum: a sensitive method.

A sensitive sequential direct radioimmunoassay of calcitonin (CT) is described. Human synthetic monomer CT was used for 125I-labelling and for preparation of standard sera. The antibody (rabbit) was directed against mid-portion and C-terminal parts of the human CT molecule. No significant cross reactivity with salmon or porcine CT was found. Separation of free from antibody-bound 125I-labelled CT was performed using a double antibody-polyethyleneglycol mixture. Dilution curves of sera from normal controls and patients with medullary thyroid carcinoma (MCT) were parallel to the standard curve. Recoveries of 25-400 ng/l CT were in the range of 88-138%. The intraassay coefficients of variation (CV) were 6% and 3% at serum concentrations of 90 and 230 ng/l respectively. The interassay CV were 13% and 10% at mean serum CT concentrations of 50 and 210 ng/l respectively. The lower limit of detection was 20 ng/l. Thirty-one healthy controls had serum CT levels in the range of 35-135 ng/l. Elevated basal serum CT concentrations were found in all of 11 patients with MCT and the serum concentrations increased markedly after pentagastrin stimulation. Subsequent thyroidectomy in eight of the 11 patients with MCT reduced basal serum CT levels, in six to within the reference range for normals.

Antibodies↗