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Biomedical subjects

J Jensen

Publications and source records attributed to J Jensen.

At least 451 records · Page 25Linked to original sources

Diagnostic accuracy of double-contrast enema and rectosigmoidoscopy in connection with faecal occult blood testing for the detection of rectosigmoid neoplasms.

Four hundred and fifty-eight consecutive subjects with a positive faecal guaiac test when screened for early detection of colorectal neoplasms were investigated with double-contrast enemas and rectosigmoidoscopy (60 cm). The results of these two methods were compared. The radiologists and endoscopists were unaware of the result of each others' examination at the time of their own investigation. Altogether ten subjects with carcinoma in the rectosigmoid area were found. The radiologists and endoscopists each overlooked four of these ten carcinomas and only four of the carcinomas were diagnosed with both methods. Fifty-six of one hundred and seven adenomas were 1 cm or larger in diameter and located in the rectum or the sigmoid colon. Thirteen of the fifty-six adenomas were missed by double contrast enema and ten by endoscopy and only thirty-three adenomas were diagnosed with both methods. Neoplasms in the rectum and the sigmoid colon are sometimes difficult to diagnose with both radiology and endoscopy. Rectosigmoidoscopy (60 cm) should therefore be used as a complement to double contrast enemas if this method is chosen for investigation of a patient with rectal bleeding.

Adenoma↗

Bone strength measurements at the proximal tibia. Penetration tests and epiphyseal compressive strength.

Three penetration tests were obtained from corresponding locations at each condyle of 19 proximal tibiae. The patterns of condylar cancellous bone strength varied little between knees. The medial condyle was the strongest with an average medial to lateral strength ratio of 1.9, and in most knees the medial condyle was strongest centrally while the lateral condyle was strongest posteriorly. The penetration strength at 5 successive 2 mm levels beneath the resected subchondral surface also showed a constant pattern of variation. Bone strength decreased significantly at first except at the posterolateral site, then tended to level off. The reduction of strength was most pronounced in the centre of the condyles. The penetration tests were good predictors of the static compressive strength of the proximal tibia. Correlation coefficients of approximately 0.90 were obtained indicating statistically highly significant correlations (p less than or equal to 0.00001). The tests were carried out with equipment developed for in vivo measurements of cancellous bone strength during total knee replacement. The findings confirm the close relationship of these investigations to conventional compression tests.

Aged↗

Effect of metoprolol and propranolol on platelet aggregation and cAMP level in hypertensive patients.

Ten patients with uncomplicated moderate essential hypertension were recruited to evaluate the effect of the non-selective beta-blocker propranolol and the beta 1-selective beta-blocker metoprolol on platelet aggregation and cAMP formation. Five patients began treatment with propranolol 80 mg b.i.d. and 5 with metoprolol 100 mg b.i.d., and after 2 weeks the treatments were exchanged. ADP- and adrenaline-induced platelet aggregation and the basal level of platelet cAMP were measured at the end of each treatment period. Platelet aggregation was tested turbidometrically, using the threshold value for irreversible aggregation, and cAMP measurements were performed using a protein-binding assay. Both ADP and adrenaline threshold values were significantly lower after propranolol than after metoprolol. The basal cAMP level was lower during propranolol than metoprolol treatment. The results indicate that platelet aggregation and basal cAMP level are influenced by beta-blockers in proportion to their affinity to different beta-adrenoceptors. This may be of value in the beta-blocker treatment of patients at high thrombotic risk.

Adenosine Diphosphate↗

Prediction of body composition by age, height, weight, and skinfold thickness in normal adults.

In order to establish an easy and reliable method for estimating body composition, the lean body mass (LBM) and the fat mass (FM) were measured in vivo in 228 normal adults (130 women and 98 men) using dual photon (153Gd) absorptiometry. In addition, skinfold thickness was measured at two sites in each subject. Multiple regression equations of LBM and FM based on age, height, and weight were computed (r = .86 to .95, SEE = 2.1 to 2.9 kg). These correlations were only slightly improved in men, but not in women, when the results of the skinfold measurements were included in the calculations. We conclude that LBM and FM can be estimated in normal adults from age, height, and weight with a predictive error below 3 kg.

Adult↗

Measurement of lean body mass and total body fat using dual photon absorptiometry.

We describe a method for measuring the lean body mass (LBM) and total body fat (FAT) by dual photon absorptiometry (DPA). A total body rectilinear scan was employed with a radiation source of 1 Ci 153Gd. The reliability of estimating the lean percent was assessed in vitro using limb phantoms consisting of ox muscle, lard, and human bone. The precision and accuracy in vitro of the lean percent determination were 1.5% and 1.9%, respectively. The accuracy error in vivo of measuring the total mass of soft tissues (TMST) was approximately 1.4%, thus yielding an overall accuracy error of the LBM of about 2.5%. The precision in vivo of the lean percent and the LBM in kg of duplicate measurements on five healthy subjects was 2.5% and 2.2%, respectively. Other estimates of the LBM and FAT, ie, the calculation according to Boddy et al6 and the skinfold thickness measurement (triceps and subscapular), were compared to the DPA measurement in 100 healthy subjects. High correlations were found between the FAT or FAT% by DPA versus (1) the FAT or FAT% calculated according to the formulae of Boddy et al, and (2) the skinfold thickness. The correlations between the FAT and FAT% by Boddy et al and the skinfold thickness were, however, moderate. The correlation between LBM by DPA and LBM by Boddy et al was highly significant (r = 0.96, SEE = 4.4%). We conclude that LBM and FAT measurements using DPA have precision and accuracy errors that are commensurate with a reliable estimation of the gross body composition.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

Oestrogen-progestogen replacement therapy changes body composition in early post-menopausal women.

Changes in body composition were investigated in a group of 136 post-menopausal women treated for at least 1 yr with combined oestrogen-progestogen therapy at three different doses, or a placebo. The body composition changes were evaluated using the urinary creatinine excretion rate as an indicator of lean body mass, and the changes in daily creatinine excretion were related to the changes in serum oestradiol and oestrone. The urinary creatinine excretion rate was significantly increased (P less than 0.001) in the group receiving high-dose hormones, and the urinary creatinine/body weight ratio was significantly increased (P less than 0.05) in all treated groups as compared with the placebo-group. The body weight remained unchanged in all groups. The relationships between the changes in daily creatinine excretion and the changes in serum oestradiol and serum oestrone were both significant (P less than 0.05). The present study suggests that high-dose post-menopausal hormone therapy changes the body composition by increasing the muscle mass and that, since the body weight remains unchanged, a proportionate decrease in the fat mass seems to occur.

Adult↗

Iron removal therapy in porphyria cutanea tarda: phlebotomy versus slow subcutaneous desferrioxamine infusion.

Twenty-five patients with overt clinical and biochemical findings of porphyria cutanea tarda took part in a study comparing intensive phlebotomy with slow subcutaneous desferrioxamine treatment. Fifteen male patients (Group A) had intensive venesection therapy. Ten patients (Group B) with associated diseases (minor thalassemia, cardiovascular impairment, pulmonary tuberculosis or severe liver cirrhosis) received 1.5 g of desferrioxamine by slow subcutaneous infusion using an automatic syringe pump 5 days a week. No patient complained of appreciable side effects. Serum iron, ferritin and uroporphyrins were normalized in all subjects by the end of treatment. The mean time necessary for complete recovery was 13.8 months (range 9-19) and 11.2 months (range 6-14) in Groups A and B, respectively. Liver function significantly improved during and after the treatments in both groups. We conclude that recovery from porphyria cutanea tarda can be achieved equally well using phlebotomy or desferrioxamine subcutaneous infusion. Phlebotomy is easily performed and remains the treatment of choice; slow subcutaneous desferrioxamine treatment, although expensive, is recommended when severe associated diseases contra-indicate venesection.

Adult↗

Cyclic changes in serum cholesterol and lipoproteins following different doses of combined postmenopausal hormone replacement therapy.

Cyclic changes in lipoproteins after sequential oestrogen-progestogen therapy were studied in a group of healthy postmenopausal women treated with three different hormone doses, and followed up for two consecutive cycles by twice weekly examinations (a total of 17 examinations). There was a significant rise in high density lipoprotein (HDL) cholesterol and a significant fall in low density lipoprotein (LDL) cholesterol closely related to the dose of the oestrogen component. Addition of the progestogen, 1 mg of norethisterone acetate, decreased the oestrogen-induced rise in HDL, but HDL levels remained higher than initial values in the high-dose (4 mg) and medium dose (2 mg) groups. The average increases in HDL cholesterol were 13%, 9% and 2% in the high-dose, medium-dose and low-dose (1 mg) groups, respectively, and the corresponding mean decreases in LDL cholesterol were 18%, 15% and 10% respectively. We conclude that postmenopausal treatment with sequentially combined oestrogen-progestogen has no adverse effects on the lipoprotein status.

Cholesterol↗

Hepatitis B virus infection in porphyria cutanea tarda.

Serum markers of hepatitis B virus (HBV) infection were determined in 82 patients with porphyria cutanea tarda (PCT). Pathogenetic factors (alcohol, thalassemia minor, drugs) and clinical and histologic findings of PCT were taken into account. The prevalence of HBV infection was very high (70.7%). Hepatitis B surface antigen (HBsAg) was positive in 14 patients (17%). Eight patients had HBV infection as the only documented acquired factor. The clinical picture and histologic findings were aggravated by HBV infection; primary hepatic carcinoma occurred in four patients with HBV infection. Liver siderosis was histologically documented in 82.6% of cases, serum ferritin was pathologically increased in 91%, confirming the role of iron overload in PCT. A correlation (p less than 0.02; chi-squared method) was found between increased serum ferritin levels and HBV infection, suggesting a possible relationship between liver siderosis and HBV clearance. HBV infection appears to be a relevant additional factor in the pathogenesis of PCT liver disease.

Adult↗

High-density lipoprotein cholesterol assay by magnesium dextransulphate precipitation.

A method for determination of high-density lipoprotein cholesterol (HDL-C) is evaluated: after precipitation of low and very low lipoprotein cholesterol in serum by magnesium dextransulphate, HDL-C is determined by an enzymatic method. The precision of the method was good: coefficient of variation 4%. The accuracy was good, evaluated by correlating HDL-C results from the present assay to the results obtained from three other HDL-C assays (n = 17): ultracentrifugation r = 0.91, phosphotungstate/MgCl2 r = 0.98, and alpha-lipoprotein determination by electrophoresis r = 0.91 (p less than 0.01). Repeated analysis showed that serum may be kept at 4 degrees C for 1 month, at -20 degrees C for 2 months, and requires -80 degrees C for longer storage. Ten patients with acute myocardial infarction showed significantly lower HDL-C from day 4 in the acute phase and during the first 3 months follow up (p less than 0.05). Eighty patients with peripheral vascular disease, who were compared to a group of matched controls, also showed significantly decreased serum HDL-C (p less than 0.01). The present HDL-C assay is easy, fast and reliable and is considered a valuable clinical test.

Adult↗

Assessment of orocoecal transit time by means of a hydrogen (H2) breath test as compared with a radiologic control method.

The definition of the orocoecal transit time by means of the hydrogen (H2) breath test is not unequivocal. In this study the orocoecal transit time as measured with an H2 breath test was compared with that obtained with a radiologic method. Two definitions of orocoecal transit time by the H2 breath test were evaluated: the time from eating to the first of three consecutively rising H2 values, and the interval to H2 values 50% above 'small-bowel level'. Transit times measured in accordance with both definitions were closely correlated to that obtained with the radiologic method (A, r = 0.84; B, r = 0.90; for both, p less than 0.001), but transit time measured by definition A gave shorter values than the radiologic method (p less than 0.05). The mean transit time in patients with constipation was significantly longer than that in normal subjects and patients with functional diarrhoea (p less than 0.05). There was a significant correlation between the difference in transit time measured with the H2 breath test and the radiologic method and the transit time measured by the control method. This may indicate that rapid transit is associated with a delayed 'colonic' rise in H2 levels and slow transit with an early H2 rise.

Adolescent↗