Tomas Berlin

25-Hydroxylase activity in subcellular fractions from human liver. Evidence for different rates of mitochondrial hydroxylation of vitamin D2 and D3

25-Hydroxylation of vitamin D2 and D3 was studied in subcellular fractions from human liver, using a technique based on isotope dilution-mass spectrometry. The mitochondrial fraction fortified with isocitrate catalysed 25-hydroxylation of vitamin D3 at a rate of about 10 pmol/mg protein X min. Under the same conditions, the rate of 25-hydroxylation of vitamin D2 was less than 2 pmol/mg protein X min. Crude microsomes fortified with NADPH catalysed 25-hydroxylation of vitamin D3 to a very low extent, and this activity was not linear with the amount of microsomal protein. A higher rate of conversion was obtained with a partially purified cytochrome P-450 fraction in the presence of NADPH-cytochrome P-450 reductase and NADPH. This fraction also catalysed 25-hydroxylation of 1 alpha-hydroxyvitamin D3 and 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol. 25-Hydroxylation of vitamin D2 could not be detected, neither with crude microsomes, nor with the microsomal cytochrome P-450 fraction. Since the assay for 25-hydroxyvitamin D2 was less sensitive than that for 25-hydroxyvitamin D3, these experiments do not rule out the presence of some 25-hydroxylase activity towards vitamin D2 in the microsomes. The results are discussed in relation to previous work in which a lower toxicity has been reported for vitamin D2 than for vitamin D3 in some mammalian species.

Transurethral microwave thermotherapy for benign prostatic hyperplasia: clinical outcome after 4 years.

PURPOSE We describe long-term results of transurethral microwave thermotherapy. We determined pretreatment variables favorable for the outcome. MATERIALS AND METHODS We followed for 4 years 187 patients treated with Prostatron software 2.0.* Preoperative evaluations consisted of score, cystoscopy, transrectal ultrasonography, urine flow and residual volume measurements. Followup examinations with score and urodynamics were performed for 4 years after transurethral microwave thermotherapy. Kaplan-Meier plots and logistic regression were used for statistical analyses. RESULTS A decrease in the number of satisfied patients was noted from 62% at 1 year after transurethral microwave thermotherapy to 23% at 4 years. Initial decrease in score and increase in urine flow were followed by increase in score and decrease in flow at the 4-year followup of the 56 patients who had not received supplementary benign prostatic hyperplasia (BPH) treatment. The Kaplan-Meier analysis estimated the median time for need of supplementary BPH treatment to be 45 months. Pretreatment urine flow greater than 10 ml. per second and an irritative score less than 5 were the only factors related to a favorable outcome. Prostate volume or energy delivered to the prostate did not influence the result. CONCLUSIONS Four years after transurethral microwave thermotherapy 23% of the initially treated group were satisfied with the result. Two-thirds had received supplementary BPH treatment. Preoperatively less obstructed patients and those with low initial irritative scores responded more favorably to transurethral microwave thermotherapy treatment.

Effect of calcium intake on serum levels of 25‐hydroxyvitamin D3

Abstract. The effects of high calcium intake on vitamin D metabolism were investigated. To the normal diet of 14 healthy men, 2 g calcium were added daily for 6–7 weeks. The mean serum concentration of 25‐hydroxyvitamin D3 increased from 73 ± 7 to 94 ± 6 nmol l‐1 (P<0·05, Students unpaired t‐test; P<0·01, paired t‐test) in the subjects receiving calcium, whereas there was only a minimal increase, from 67 ± 5 to 71 ± 4 nmol l‐1 in a control group on a normal diet. At the end of the study the difference between the test group and the controls was highly significant (P<0·005). The calcium loading caused a statistically significant depression of the serum levels of 1,25‐dihydroxyvitamin D. The results obtained are in agreement with previous studies in rats and indicate that calcium intake is of some importance for the serum level of 25‐hydroxyvitamin D3. The findings are discussed in relation to our previous finding that there is a relationship between high 25‐hydroxyvitamin D3 levels and hypercalciuria in renal‐stone formers.

High circulating levels of 25-hydroxyvitamin D3 in renal stone formers with hyperabsorptive hypercalciuria

Normocalcaemic male stone formers, 31-51 years old (n = 108) on a free diet, were divided into a hypercalciuric group (n = 47) with calcium excretion rates higher than 8.0 mmol/24 h, a normocalciuric group (n = 32) with calcium excretion rates below 6.1 mmol/24 h and an intermediate group (n = 29). There were no statistically significant differences between the hypercalciuric and the normocalciuric groups with respect to serum levels of calcium, phosphate, creatinine, urate, ALAT, albumin, PTH, 1,25-dihydroxyvitamin D or urinary excretion of cAMP. The group of patients with high calcium excretion had significantly higher serum levels of 25-hydroxyvitamin D3 (75 +/- 4 nmol/l) than the group with low calcium excretion (57 +/- 4 nmol/l) (p less than 0.002), while the group of patients with intermediate calcium excretion had 25-hydroxyvitamin D3 levels between the other two groups (69 +/- 4 nmol/l). A highly accurate method based on isotope dilution-mass spectrometry was used to assay 25-hydroxyvitamin D3. Of the patients with hypercalciuria (n = 47), seven were classified as hyperabsorbers on the basis of calcium load tests. These patients were found to have even higher serum levels of 25-hydroxyvitamin D3 (108 +/- 10 nmol/l)--significantly higher than that of the hypercalciuric patients as a whole. The above study was carried out in March 1983. In September, the group of patients with high urinary calcium excretion also had significantly higher levels of 25-hydroxyvitamin D3 than the group of patients with low calcium excretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Relation Between Hypercalciuria and Vitamin D3-Status in Patients with Urolithiasis

Patients with urolithiasis were divided into two groups, one (n = 38) with a urinary excretion of calcium exceeding 6.0 mmol/24 h and one (n = 32) with a calcium excretion lower than 6.1 mmol/24 h. The group of patients with a high urinary excretion of calcium had a significantly higher level of 25-hydroxy vitamin D3 (26.2 +/- 1.6 ng/ml) than had the group of patients with a normal urinary excretion of calcium (17.6 +/- 0.9 ng/ml) (p less than 0.001). A highly specific and accurate method, based on isotope dilution--mass spectrometry was used in the assay of 25-hydroxy vitamin D3. There was no over-all correlation between level of 25-hydroxy vitamin D3 and serum level of calcium (r = 0.1). The results are in accordance with the contention that the vitamin D3-status might be of some importance for the development of hypercalciuria in these patients.

Transurethral microwave thermotherapy of benign prostatic hyperplasia : Do any pretreatment conditions predict the result ?

OBJECTIVES To investigate the long-term effect of transurethral microwave thermotherapy (TUMT) treatment and find possible predictors of a favourable outcome. METHODS Men with symptomatic benign prostatic hyperplasia (BPH) (n = 339) were examined before undergoing TUMT. The pretreatment evaluation included two or more of the following: cystoscopy, ultrasonic examination of the prostate, urine flow rate, residual urine volume and Madsen symptom score. The urodynamic measurements and Madsen score were repeated after 3, 6 and 12 months. Six different groups, based on pretreatment examinations or energy given during TUMT, were analysed. RESULTS The Madsen score was significantly reduced and the score reduction was similar in all groups. Residual urine did not change significantly and flow rate increased only marginally. At 12 months, 56% of the men were satisfied with the treatment result, 29% had received additional treatment because of insufficient relief symptoms, while the remaining 15% were not satisfied but decided not to undergo further treatment at present. CONCLUSION The reduction in the Madsen score remained stable during 1-year follow-up. None of the investigated pretreatment findings were predictive of a favourable treatment result. Since TUMT did not increase peak urinary flow significantly, men with BPH symptoms and unobstructed micturition appear to be the most suitable group for treatment. This group of men showed the same symptomatic improvement as the other investigated groups.

Studies on the relationship between vitamin D3 status and urinary excretion of calcium in healthy subjects: effects of increased levels of 25-hydroxyvitamin D3.

The metabolic consequences of a rapid increase in vitamin D status in healthy subjects were investigated. Circulating levels of 25-hydroxyvitamin D3 were increased by 224% in 12 healthy men by giving oral vitamin D3 for 7 weeks and by 200% in 15 healthy women by UVB irradiation for 7 weeks. No statistically significant effects on the serum levels of calcium, phosphate, creatinine, urate, albumin, PTH, basal urinary excretion of calcium, fasting urinary excretion of cAMP, or urinary excretion of calcium after calcium load tests were observed with the unpaired t-test. With the paired t-test the small stimulatory effects (about 25%) on basal urinary excretion of calcium became statistically significant in both experiments. The ratio between calcium and creatinine in fasting urine was significantly elevated following UVB irradiation (from 0.11 +/- 0.02 to 0.21 +/- 0.04, p less than 0.025 unpaired t-test, p less than 0.02 paired t-test) but not after oral intake of vitamin D3. The level of 1,25-dihydroxyvitamin D in serum was not affected to a statistically significant degree by oral vitamin D3, whereas there was a slight decrease from 48 +/- 3 to 39 +/- 3 pmol/l following UVB irradiation. It is concluded that an increase in the concentration of 25-hydroxyvitamin D3 up to about 125 nmol/l has small and negligible effects on calcium homeostasis in healthy subjects. This finding is discussed in relation to our previous finding that hypercalciuric renal stone formers have elevated serum levels of 25-hydroxyvitamin D3 as compared with normocalciuric stone formers and healthy subjects.

Biosynthesis of prostaglandins in microsomes of human skeletal muscle and kidney

The capacity of human skeletal muscle, renal cortical and renal medullary microsomes to synthesize prostaglandins (PGs) from exogenous precursor was investigated. The microsomal fractions were incubated with [1-14C]-labelled arachidonate ([14C]-AA) in the absence and in the presence of reduced glutathione (GSH). [14C]-PGs formed in the incubates were extracted, separated by thin-layer chromatography and quantified using liquid scintillation spectrometry. [14C]-labelled PGE2, PGF2 alpha and 6-keto-PGF1 alpha were found to be the principal products of microsomal PG formation and appeared in similar relative quantities in the incubates of all three tissues studied. In some incubates of renal cortical and renal medullary microsomes formation of smaller relative amounts of [14C]-PGD2 and thromboxane B2 was also noted. In addition, formation of substantial amounts of a polar, not yet identified compound was frequently observed in all incubates. In the absence of GSH, [14C]-6-keto-PGF1 alpha was the main PG formed by microsomes of all of the three tissues. At the expense of 6-keto-PGF, the addition of GSH resulted in an almost 2-fold stimulation of [14C]-PGF2 alpha formation in the skeletal muscle and renal cortical incubates, whereas in the renal medullary incubates an increase in the relative amounts of [14C]-PGE2 was observed. The PG synthetic capacity was highest in the skeletal muscle and lowest in the renal cortical microsomes. The results demonstrate a considerable capacity of human skeletal muscle and of the renal cortex and renal medulla to synthesize prostacyclin. Furthermore, the data reveal GSH-dependent differences in the expression of PG biosynthesis in these tissues. The GSH-dependent differentiation of PG synthesis may reflect a mechanism of adaptation of local PG production to the physiological processes.

On the regulatory importance of 1,25-dihydroxyvitamin D3 and dietary calcium on serum levels of 25-hydroxyvitamin D3 in rats

The serum level of 25-hydroxyvitamin D3 in rats was found to vary with the dietary intake of calcium. An increase in the dietary intake of calcium was found to be associated with an increase in the concentration of 25-hydroxyvitamin D3 and a decrease in the concentration of 1,25-dihydroxyvitamin D in serum. Intraperitoneal administration of 1,25-dihydroxyvitamin D3 was found to depress the serum concentration of 25-hydroxyvitamin D3 in rats on both medium and high calcium diets. These changes in the serum levels of 25-hydroxyvitamin D3 were not associated with statistically significant changes in the activity of mitochondrial vitamin D3 25-hydroxylase in the liver. Possible mechanisms for the regulation of the level of circulating 25-hydroxyvitamin D3 in serum are discussed.

Does Transurethral Microwave Thermotherapy (TUMT) Affect Emission of Semen

UNLABELLED In the patients choice of treatment for symptomatic BPH today, more importance has become attached to disturbances in sexual function as a side-effect. This study concerns analyses of semen after TUMT. MATERIAL AND METHODS TUMT was performed with Prostatron, Prostasoft 2.0. Fourteen men were able to provide semen specimens for this study. One sample was collected before and one three to seven months after TUMT. The analyses of semen included determinations of volume, sperm number, sperm morphology and secretory contribution of seminal vesicular and prostatic fluid. RESULTS One of the fourteen men could not provide a post-TUMT specimen, despite normal erection. One patient developed pain in the perineum/prostate region post-TUMT when ejaculating and showed azoospermia after the treatment. In analysing the whole group, no statistically significant differences were found between pre- and post-TUMT specimens, regarding semen emission (semen volume, total sperm number, total fructose and zinc) or sperm morphology.