Application of the membrane filter technique to bromodeoxyuridine immunochemistry for exfoliative cytology

The membrane filter technique for smear specimens of tumors in bromodeoxyuridine (BrdU) immunochemistry is described. The staining results of Raji cells processed using the filter technique was compared with that obtained by the conventional cytospin method. Although the BrdU mean labeling index (LI) for in cytospin specimens was almost the same as the LI in membrane filter specimens, filter specimens showed excellent staining and less cell destruction compared with those processed by cytospin. Small amounts of tumor specimens such as squamous cell carcinoma and polymorphous low-grade adenocarcinoma also were processed using the membrane filter appliance. For squamous cell carcinoma, the LI for the filter specimens was 5.36+/-0.38 and that of the paraffin sections was 5.56+/-0.38. The membrane filter technique provided relatively undamaged specimens for exfoliative cytology and will be useful for immunohistochemical evaluation of tumor cells and for routine, noninvasive cytological screening.

Differential localization of prohormone convertases PC1 and PC2 in two distinct types of secretory granules in rat pituitary gonadotrophs

Prohormone convertases PC1 and PC2 are endoproteases involved in prohormone cleavage at pairs of basic amino acids. There is a report that prohormone convertase exists in the rat anterior pituitary gonadotrophs, where it had previously been considered that proprotein processing does not take place. In addition to luteinizing hormone and follicle-stimulating hormone, rat pituitary gonadotrophs contain chromogranin A (CgA) and secretogranin II (SgII), two members of the family of granin proteins, which have proteolytic sites in their molecules. In the present study we examined whether there is a close correlation between subcellular localization of prohormone convertases and granin proteins. Ultrathin sections of rat anterior pituitary were immunolabeled with anti-PC1 or -PC2 antisera and then stained with immunogold. Immunogold particles for PC1 were exclusively found in large, lucent secretory granules, whereas those for PC2 were seen in both large, lucent and small, dense granules. The double-immunolabeling also demonstrated colocalization of PC2 and SgII in small, dense granules and of PC1, PC2, and CgA in large, lucent granules. These immunocytochemical results suggest that PC2 may be involved in the proteolytic processing of SgII and that both PC1 and PC2 may be necessary to process CgA.

Fine structure of the retino-optic nerve junction in the chicken

The aim of this study is to investigate a fine structure of the retino-optic nerve junction in the chicken. We especially focused on the myelin sheaths and astrocytes in the intraocular optic nerve (ION) and its adjoining parts. A part of the axons of retinal nerve fiber layer (NFL) were myelinated. Ganglion cell axons were ensheathed by loose myelin in the NFL and by a compact one in the ION and optic nerve (ON). Myelin structure changed from loose type to a compact one within the very narrow NFL-ION junction. Loose myelin forming cells are dark type of oligodendrocytes in the retina. From the most peripheral ON to the choroidal part of ION, astrocytes contained abundant microtubules. The optic nerve around the lamina cribrosa is exposed to mechanical force during eye movement. It is suggested that these microtubules may perform the cytoskeletal function. Astrocytes in the retinal part of ION had longer processes filled with abundant gliofilaments. They may provide the mechanical support for the ganglion cell axons, which are exposed directly to intraocular pressure. Although astrocytes in the retinal level of ION extended their processes into the retina, their soma was never found in the retina.

Greater effect of dietary potassium tripolyphosphate than of potassium dihydrogenphosphate on the nephrocalcinosis and proximal tubular function in female rats from the intake of a high-phosphorus diet

We examined whether a difference in potassium dihydrogenphosphate (KH2PO4) and potassium tripolyphosphate (K5P3O10) as dietary phosphorus sources could differentially effect the nephrocalcinosis and proximal tubular function in female rats. Rats were fed on a diet containing KH2PO4 or K5P3O10, at the normal phosphorus level (normal phosphorus diet) or at a high phosphorus level (high-phosphorus diet) for 21 d. Nephrocalcinosis, as confirmed by a histological examination, was apparent in all rats fed on the high-phosphorus diet, and this condition was more severe in those rats fed on K5P3O10 than in those fed on KH2PO4. As indicators of the proximal tubular function, the N-acetyl-beta-D-glucosaminidase activity in urine and the urinary beta2-microglobulin excretion were significantly increased in those rats fed on the high-phosphorus diet containing K5P3O10. These results indicate that the intake of a high-phosphorus diet, more strongly influenced the nephrocalcinosis and proximal tubular function when K5P3O10 rather than KH2PO4 was used as the dietary phosphorus source.

Distribution of reticulospinal neurons in the chicken by retrograde transport of WGA-HRP

To determine the distribution of reticulospinal (RS) neurons in the chicken, WGA-HRP was injected into the cervical or lumbosacral enlargement either unilaterally or bilaterally. The brainstem reticular nuclei sent largely descending fibers to both the spinal enlargements. The mesencephalon (medial and lateral mesencephalic reticular formation) and the rostral pons (nucleus reticularis [n.r.] pontis oralis) project mainly to the cervical enlargement. RS neurons were mainly distributed from the pontomedullary junction to the rostral medulla including n. r. pontis caudalis and pars gigantocellularis, n. r. gigantocellularis, n. r. parvocellularis, n. r. paragigantocellularis, and n. r. subtrigeminalis. It is suggested that the majority of these neurons send axons at least as far as the lumbosacral enlargement. In the lower medulla, RS neurons were distributed in the dorsal and ventral parts of the central nucleus of the medulla.

Dietary fructooligosaccharides modify intestinal bioavailability of a single dose of genistein and daidzein and affect their urinary excretion and kinetics in blood of rats

The influence of dietary fructooligosaccharides (FOS) on bioavailability of genistein and daidzein in rats was estimated by measuring their concentrations in plasma collected from three different veins and in urine after a single intragastric administration of isoflavone conjugates. Sprague-Dawley male rats (6 wk old, n = 22) were fed a purified control (AIN-93G) diet or a FOS diet (AIN-93G + 5% FOS) for 7 d. A single dose of soy isoflavone conjugates, i.e., 8.5 mg as genistein and 33 mg as daidzein/kg body, was administered via a stomach tube at d 5. Blood samples were collected after administration via catheters in the portal and central veins and by puncture of the tail vein. The isoflavones in plasma and urine were analyzed by time-resolved fluoroimmunoassay. The genistein concentration in the portal blood increased rapidly, reaching a peak of 3.5 micromol/L in both groups at 1 h after administration. The concentrations in the central and tail venous blood were approximately half of those in the portal blood. In the FOS-fed group, both genistein and daidzein remained detectable at 24 and 48 h in the tail venous plasma. The urinary excretion of both isoflavones in the 24- to 48-h period after administration was significantly higher in the FOS-fed group than in the control group. The difference between the portal and central veins indicated hepatic uptake, probably leading to conjugation of aglycones and excretion into bile. FOS modified the absorption and enterohepatic recirculation of isoflavones.

Laterality of the spinocerebellar axons and location of cells projecting to anterior or posterior cerebellum in the chicken spinal cord

In the cervical and lumbosacral enlargements of the chicken, there are seven spinocerebellar nuclei, the Clarke's column, the spinal border cells, the ventral margin of the ventral horn of both enlargements, and the ventral marginal nucleus in the lumbosacral enlargement. In the present study, we investigated the laterality of spinocerebellar tract axons and the distribution of the spinocerebellar tract neurons projecting into the anterior or posterior part of the cerebellum in these seven nuclei by retrograde transport of wheat germ agglutinin-horseradish peroxidase. The spinocerebellar tract neurons with uncrossed axons were found in the cervical Clarke's column and the cervical spinal border cells, and with crossed ones in the lumbar Clarke's column, lumbar spinal border cells, lumbar lamina IX included in the ventral margin of the ventral horn of the lumbosacral enlargement, and the ventral marginal nucleus. The ventral margin of the ventral horn of the cervical enlargement and lumbar lamina VIII included in the ventral margin of the ventral horn of the lumbosacral enlargement issued spinocerebellar tract axons bilaterally. The spinocerebellar tract neurons of the lumbar spinal border cells and lumbar lamina IX projected to the anterior part of the cerebellum only. And those of the other nuclei projected to both the anterior and posterior parts.

Distribution of reticulocerebellar neurons in chicken reticular formation

The distribution of reticulocerebellar (RC) neurons was examined by the retrograde transport of horseradish peroxidase (HRP) or wheat germ agglutinin bound to HRP (WGA-HRP) in 7 White Leghorn chickens. A large number of labeled cells were found in the nucleus reticularis pontis caudalis (RP) of the pontomedullary junction and in the nucleus reticularis gigantocellularis (Rgc), parvocellularis (Rpc), subtrigiminalis (Rst), paragigantocellularis (Rpg) and paramedianus (RpaM) in the medulla. Slightly ventral to the vestibulocochlear nerve were many large RC neurons arranged in a longitudinal manner along the lateral edge of the brainstem reticular formation (the Dorsolateral edge cells, DLe cells). RC neurons were most numerous in the Rgc and accounted for 31.9% of the total number of labeled cells, followed by RP (24.2%), Rpc (12.7%), Rpg (10.8%), RpaM (6.7%), DLe cells (6.3%) and Rst (4.9%). The great number of RC neurons was found around the levels of the vestibulocochlear nerve.

A trial of oolong tea in the management of recalcitrant atopic dermatitis

BACKGROUND

Mild cases of atopic dermatitis (AD) generally improve with standard treatment. However, standard treatment fails many patients with recalcitrant AD skin lesions. Study results in animal models have demonstrated that the administration of tea (ie, green, black, or oolong) has suppressed type I and type IV allergic reactions.

OBJECTIVE

To test the effectiveness of oolong tea in the treatment of recalcitrant AD.

PATIENTS

Although 121 patients with recalcitrant AD were enrolled in the study, 118 patients completed the open study.

METHODS

Patients were asked to maintain their dermatological treatment. However, they were also instructed to drink oolong tea made from a 10-g teabag placed in 1000 mL of boiling water and steeped for 5 minutes. This amount was then divided into 3 equal servings and 1 serving was drunk daily after 3 regular meals. Photographs of 2 or 3 representative lesion sites were taken at baseline and at 1 and 6 months and the severity of pruritus was assessed on a 6-point Lickert-like scale ranging from markedly improved (>50% improvement) to worsened.

RESULTS

After 1 month of treatment 74 (63%) of the 118 patients showed marked to moderate improvement of their condition. The beneficial effect was first noticed after 1 or 2 weeks of treatment. A good response to treatment was still observed in 64 patients (54%) at 6 months.

CONCLUSION

The therapeutic efficacy of oolong tea in recalcitrant AD may well be the result of the antiallergic properties of tea polyphenols.

Causal relationship between a case of severe hepatic dysfunction and low exposure concentrations of N,N-dimethylformamide in the synthetics industry

A 19-year-old man suffered hepatic dysfunction after 5 months of exposure to N,N-dimethylformamide (DMF) at his job in the synthetic resins industry. Laboratory data revealed elevated levels of AST (578 IU/l), ALT (1193 IU/l), and gamma-GTP (107 IU/l), no viral infection with HAV, HBV, or HCV, and no history or evidence of hepatic injury, although he did have a slight abdominal abnormality and swelling which was detected by palpation. His urinary N-methylformamide level, as a biological exposure index of DMF, was 42.8 mg/l, indicating 10-30 ppm of DMF exposure. After 2 months he was reinstated in two workplaces, the former where he worked in the morning and the other in the afternoon where environmental DMF concentrations were less than those in the former workplace. On the 18th day after his reinstatement, his liver function became exasperated again. After the second period of medication and one month of rest from work, he had fully recovered and was reinstated, but to a workshop without DMF exposure.

Consumption of wholemeal rye bread increases serum concentrations and urinary excretion of enterolactone compared with consumption of white wheat bread in healthy Finnish men and women

Rye is an important source of plant lignans in Finland. In the present crossover trial we wanted to study the effect of rye bread as part of the usual diet on serum and urine enterolactone (ENL) concentrations in healthy volunteers. Eighteen men aged 43 (sem 2.0) years and twenty-one women aged 43 (sem 1.6) years consumed wholemeal rye bread and white wheat bread in random order for 4 weeks. The bread periods were separated by a 4 week wash-out period. The breads provided at least 20% of the daily energy intake. The mean intakes of rye bread were 219 (sem 14.6) and 162 (sem 5.3) g/d and those of wheat bread were 200 (sem 9.6) and 153 (sem 5.8) g/d for men and women respectively. Blood samples were collected from all subjects and three 24 h urine samples were collected from ten men and twelve women at the end of both bread periods for the determination of serum concentration and urinary excretion of ENL. The mean serum ENL concentrations in both men and women at the beginning of baseline period and at the end of the rye-bread period remained constant and were significantly higher than those at the end of the wheat-bread period. Correspondingly, daily urinary ENL excretion increased significantly during the rye-bread period compared with the wheat-bread period and was 5- and 10-fold higher in men and women respectively in comparison with the amount of plant lignan precursors measured in the rye bread. These data indicate the presence of other precursors for ENL in rye which are not detected by the current method of measuring plant lignans in food. The possible role of fibre in enhancement of the formation of mammalian lignans from their plant precursors in the gut also remains to be determined.

Ultrastructural characteristics and lectin-binding properties of M cells in the follicle-associated epithelium of chicken caecal tonsils

To clarify the nature of M cells, the detailed ultrastructural characteristics and lectin-binding properties of M cells were investigated in follicle-associated epithelium (FAE) of chicken caecal tonsils. M cells presented various outlines from columnar to dome shaped. Their polymorphism was dependent on the number of harboured intraepithelial migrating cells. The lighter and larger nuclei of M cells were situated at more apical levels in the epithelial lining compared with those of neighbouring microvillous epithelial cells. The microvilli, which were significantly shorter and thicker than those of adjacent microvillous epithelial cells, were sparsely distributed or completely absent on the apical surfaces of M cells. In general, the apical cytoplasm of M cells without microvilli protruded slightly into the intestinal lumen. Numerous small vesicles were often contained in the apical cytoplasm. The numerous small invaginations of the apical and lateral cell surfaces suggested active transportation of luminal substances. No canaliculi existed in the apical cytoplasm of M cells whereas they were often detected in the neighbouring microvillous epithelial cells. A noteworthy finding was the frequent detection of multivesicular bodies in the apical cytoplasm of M cells. These multivesicular bodies suggest some degradation of ingested luminal substances during transcytoplasmic transportation. WGA and 4 other lectins strongly reacted with all epithelial cells except for M cells, this negativity suggesting a means of detecting M cells in chicken caecal tonsils. Three lectins, DSL, ConA and Jacalin, reacted weakly with the glycocalyx on M cells. The positive reactivity might allow chicken M cells to be utilised for specific antigen delivery into the mucosal immune system in some parenteral vaccinations.

Chronic phosphorus supplementation decreases the expression of renal PTH/PTHrP receptor mRNA in rats

Dietary intake of high levels of phosphorus is known to increase serum levels of parathyroid hormone (PTH); however, how this increased serum PTH affects the action of PTH in major target tissues, particularly by kidney, remains unknown. In the present study, we therefore undertook to clarify this point in intact animals fed a high-P diet by examining various parameters of PTH action. Twelve weanling Wistar male rats were assigned randomly to two groups: a control group with dietary Ca:P = 1:1 and a high-P group (Ca:P = 1:3) fed the standard AIN-76 diet supplemented with P (0.5 and 1.5 g/100 g of diet). After 3 weeks of feeding, in the high-P diet group, we observed that serum Ca was lowered, without a difference in serum P, when compared to the control group. Excretion of urinary cAMP, an index of renal PTH action, was also decreased, with higher excretion of urinary P in those rats fed the high-P diet. In agreement with the decreased cAMP excretion, a clear reduction in PTH/PTH-related protein (PTHrP) receptor gene expression as estimated by Northern blotting was observed in the kidney, despite increased levels of serum PTH. Thus, the present study indicated that a high-P diet reduces PTH action in the kidney, though the serum PTH is increased.

High P diet induces acute secretion of parathyroidhormone without alteration of serum calcium levels in rats

To find whether a high phosphorus (P) diet stimulate the secretion of PTH, a high-P diet was fed to rats and an increase in serum P levels has occurred. All rats were fed a control diet (0.5% calcium (Ca), 0.5% P) for 7 days, while they were being adapted, for 1 hour at 8:00 AM and again at 8:00 PM. Four groups were switched to the high-P diet (0.5% Ca, 1.5% P) at the time of their morning meal for 1 hour. The other 4 groups continued to receive the control diet. Blood samples were collected from the rats in the remaining group, which served as a pre-feeding control. Every 30 minutes after the start of feeding (30, 60, 90, 120 min), blood samples were collected from the rats in the groups fed the control and high-P diets. Serum P concentrations increased upon intake of the high P diet, within 30 minutes after the start of feeding. Serum PTH levels also increased upon intake of the high P diet, within 30 minutes after the start of feeding, and the levels were significantly higher in the high-P group than in the control group. However, no significant difference was observed in serum Ca levels between the two groups. From these results, our findings suggest that an increase in serum P concentration might be a trigger of PTH secretion without any changes of serum calcium levels.

The organization of the spinocerebellar tract neurons in the chicken

The organization of spinocerebellar tract (SCT) neurons in the chicken was studied quantitatively using retrograde wheat germ agglutinin-horseradish peroxidase labelling. The chicken spinal cord was divided into five regions based on the distribution of SCT neurons: the cervical region (the spinal segments [SS], 1-12, which contained 32% of the total number of SCT neurons), the cervical enlargement (SS13-15, 13.4%), the thoracic region (SS16-20, 13%), the thoraco-lumbosacral region (SS21-26, 34.6%), and the posterior lumbosacral region (SS27-30, 7%). Clarke's column was found in two regions, a cervical one (SS12-16) and a lumbar one (SS21-28). The spinal border cells were less numerous and also present in two parts, a cervical one (SS10-15) and a caudal one (SS20-24). SCT neurons of the ventral part of the ventral horn were found in the cervical enlargement and SS16 (lamina VIII), and in the thoraco- and posterior lumbosacral regions (laminae VIII and IX). The ventral marginal nucleus consisted exclusively of SCT neurons but the major and minor marginal nuclei did not contain SCT neurons. In the cervical region most of SCT neurons were observed in the ventral horn, while the central cervical nucleus, which consists of SCT neurons in mammals, was not identified in the chicken.

Comparative study of the lamina cribrosa and the pial septa in the vertebrate optic nerve and their relationship to the myelinated axons

The optic nerve contains the connective tissues, i.e. the lamina cribrosa and pial septa. This report presents a histological comparison of the lamina cribrosa and pial septa in the five classes (mammals, birds, reptiles, amphibians and teleosts) of vertebrates. Furthermore, the distribution of myelinated fibers was observed from the optic nerve through the retina in the same animals. The lamina cribrosa is found in mammals except for mice, and in birds. Structural complexity of the lamina was different in animals but generally dependent of the optic nerve thickness. The pial septa were present in the optic nerve proper of the mammals except for the mice, in birds and in a part of teleosts. Fasciculation of the optic nerve by the pial septa tended to be more prominent as the optic nerve become thicker. The optic nerve consisted of largely myelinated fibers in vertebrates. The retina contained some myelinated fibers in submammals but was thoroughly devoid of myelinated fibers in mammals. The borderline between myelinated and unmyelinated portions in the optic nerve of different species did not related to the lamina cribrosa. Amphibians had exceptionally only a few myelinated fibers in the optic nerve and no myelinated fibers in the retina.

Skin barrier function in patients with completely healed atopic dermatitis

Although it has been well established that the dry skin often seen in patients with atopic dermatitis shows a deranged barrier function, there is no unanimity of opinion as to whether the barrier in normal-appearing skin of patients with the disease is deranged or not. Hence, it remains unclear whether individuals with atopic dermatitis constitution have an intrinsic derangement of skin barrier function or not. To settle this problem, in the present study we examined transepidermal water loss and stratum corneum water content in normal appearing skin of the upper back of 16 patients with completely healed atopic dermatitis who had been free from skin symptoms for 5 years or more, 30 patients with active atopic dermatitis, and 39 healthy subjects. The transepidermal water loss values and the stratum corneum water content values in normal-appearing skin of the completely healed patients were not different from the values in normal controls. These findings indicate that skin barrier function is not disturbed in patients with completely healed atopic dermatitis.

Increased extra domain-A containing fibronectin and hepatic dysfunction during septic response: an in vivo and in vitro study

A massive inflammatory reaction resulting from systemic cytokine release is the common pathway underlying sepsis or multiple organ dysfunction. The role of extra domain sequence A-containing fibronectin (EDA+FN) formation during the septic response is not known. The present study investigates the role of EDA+FN during the septic response under in vitro and in vivo conditions. The direct effects of interleukin-1, interleukin-6, and tumor necrosis factor-alpha on EDA+FN production were evaluated in primary cultured human hepatocytes and fibroblasts. Serial plasma EDA+FN levels were measured using an enzyme-linked immunosorbent assay in 24 patients who developed postoperative sepsis following general abdominal surgery of which there were 17 survivors and 7 non-survivors. EDA+FN secretion was significantly increased in cultured hepatocytes but not fibroblasts at 24 and 48 h following exposure to IL-1 compared to controls. In the clinical setting plasma EDA+FN levels in non-survivors were significantly higher than in survivors. Moreover, the EDA+FN levels were correlated closely with liver function tests. EDA+FN levels may represent a specific marker of vascular injury or systemic inflammatory response syndrome that is associated with an adverse clinical outcome.

Time-resolved fluoroimmunoassay of plasma daidzein and genistein

We present a method for the determination of the phytoestrogens daidzein and genistein in plasma (serum). These weakly estrogenic isoflavones occur in soybeans and in smaller amounts in some other beans and plants. It has been suggested that they may afford protection against prostate and breast cancer. The method is based on time-resolved fluoroimmunoassay (TR-FIA) using a europium chelate as a label. After synthesis of 4'-O-carboxymethyl-daidzein and 4'-O-carboxymethyl-genistein the compounds are coupled to bovine serum albumin (BSA), then used as antigens to immunize rabbits. The tracers with the europium chelate are synthesized using the same 4'-O-derivative of the isoflavones. After enzymatic hydrolysis and ether extraction the immunoassay is carried out using the VICTOR 1420 multilabel counter (Wallac Oy, Turku, Finland). The antisera cross-reacted to some extent with some isoflavonoids but not with flavonoids. The cross-reactivity seems not to influence the results, which were highly specific for both compounds. The correlation coefficients between the TR-FIA methods and the reference method based on isotope dilution gas chromatography-mass spectrometry were high; r-values were about 0.95-0.99 depending on concentration. The intra-assay coefficients of variation (CV%) for daidzein and genistein at three different concentrations vary 3.2-4.5 and 3.2-4.1, respectively. The inter-assay CVs vary 5.0-6.3 and 4.5-5.3, respectively. The working ranges of the daidzein and genistein assays are 1.0-216 and 1.7-370 nmol/l, respectively. The plasma values (n = 80) of daidzein and genistein are very low in Finnish subjects (mean for daidzein, 3.8+/-6.8 and for genistein, 3.2+/-7.6 nmol/l; median value for daidzein 1.5 and for genistein 1.4 nmol/l).

Developmental study of the shortened spinal cord in the adult tiger puffer fish, Takifugu rubripes (Teleostei)

ABSTRACT The spinal cords of vertebrates are generally divided into the cord proper and the minute filum terminale. While the spinal cord extends the entire length of the vertebral canal in the adult tiger puffer, Takifugu rubripes, the cord proper is greatly reduced in length and almost all of the canal is occupied by the filum terminale, which is tape-like rather than thread-like. The dorsal and ventral roots of the spinal nerves extend, respectively, above and below the filum terminale; as a whole, these form a massive cauda equina. Supramedullary cells are found in the rostral half of the medulla oblongata caudal to the cerebellum. In 4-mm long tiger puffers, the spinal cord is cylindrical and supramedullary cells are found in the rostral half of the cord. In 7-mm puffers, the longitudinally arranged ventral roots appear ventrally in the middle portion of the spinal cord. In 15-mm puffers, the dorsal and ventral roots run longitudinally along the spinal cord and have noticeably increased in number. Supramedullary cells are located in the rostral 15% of the cord. In 21-mm puffers, the spinal cord in large part becomes dorsoventrally flattened. In 30-mm puffers, the spinal cord becomes much flatter, and supramedullary cells now are located mainly in the medulla oblongata. These observations indicate that formation of the shortened spinal cord proper is due to at least two developmental processes. First, the elongation of the spinal cord proper is remarkably less than that of the vertebral canal. Second, the bulk of the spinal cord proper is translocated to the cranial cavity, where it is transformed into part of the medulla oblongata.

Phyto-oestrogen content of berries, and plasma concentrations and urinary excretion of enterolactone after a single strawberry-meal in human subjects

Quantitative data on phyto-oestrogen, particularly lignan, content in edible plants are insufficient. We, therefore, measured isoflavonoids and lignans in nine edible berries using an isotope dilution gas chromatography-mass spectrometry method for foods and found substantial concentrations of the lignan secoisolariciresinol (1.39-37.18 mg/kg DM), low amounts of matairesinol (0-0.78 mg/kg DM) and no isoflavones. To determine pharmacokinetics and urinary excretion pattern of the mammalian lignan enterolactone derived from plant lignans, a study with human subjects was conducted. Five healthy women and two men consumed, after a 72 h period of a phyto-oestrogen-free regimen, a single strawberry-meal containing known amounts of plant lignans. Basal and post-meal blood and urine samples were collected at short intervals. The samples were analysed using time-resolved fluoroimmunoassay of enterolactone. The meal increased plasma concentration of enterolactone after 8-24 h and in urine in the 13-24 h and 25-36 h urine collections. High individual variability of the metabolic response was observed. Enterolactone excreted in the urine collected throughout the 48 h post-meal yielded on average 114% of the plant lignans consumed. It is concluded that berries containing relatively high concentrations of plant lignans contribute to plasma and urinary levels of mammalian enterolactone in human subjects.

Rapid analysis of phytoestrogens in human urine by time-resolved fluoroimmunoassay

A time-resolved fluoroimmunoassay (TR-FIA), with europium labeled phytoestrogens as tracers, was developed for the quantitative determination of enterolactone, genistein and daidzein in human urine. The aim was to create a method for the screening of large populations in order to assess the possible correlations between the urinary levels and the risk of Western diseases. After the synthesis of the 5'-carboxymethoxy derivative of enterolactone and 4'-O-carboxymethyl derivatives of daidzein and genistein, the respective compound was coupled to bovine serum albumin and then used as an antigen in the immunization of rabbits. The same derivatives of the phytoestrogen were used in preparing the europium tracers. After the enzymatic hydrolysis, the TR-FIA was carried out using the Victor 1420 multilabel counter. The method has sufficient sensitivity to measure the phytoestrogens at concentrations even below 5 nmol/l. The intra- and inter-assay coefficients of variation, at three different concentrations, varied from 1.9 to 5.3 and from 2.4 to 9.7, respectively. We measured urinary enterolactone, genistein and daidzein in 215 samples from Finnish healthy women and found that more than 50% of the values ranged between 1 and 7, <0.1 and 0.6 and below 0.6 micromol/24 h, respectively. The TR-FIA method including only a hydrolysis step gave higher values than those measured by gas chromatography-mass spectrometry (GC-MS). However, the assay results by the present method showed strong correlation with those obtained by GC-MS. It is concluded that the TR-FIA is suitable for population screening of urinary phytoestrogens.