Metallothionein gene expression differs in earthworm populations with different exposure history.

Metals are persistent pollutants in soils that can harm soil organisms and decrease species diversity. Animals can cope with metal contamination with the help of metallothioneins, small metal-binding proteins involved in homeostasis and detoxification of metals. We studied the expression of metallothionein with qPCR in a small, epigeic earthworm, Dendrobaena octaedra. We compared expression patterns and metal body content in earthworms collected from two sites with different metal contamination histories: Harjavalta, contaminated by a Cu-Ni smelter operational for over 50 years, and Jyväskylä, an uncontaminated site. Earthworms from both sites were also experimentally exposed to different concentrations of Cu (control, 50, 100 or 200 mg/kg) or Zn (control, 75, 150 or 300 mg/kg) for 7, 14 or 28 days to determine if there is a time related dose-response in gene expression. Population comparison showed that metallothionein expression was higher in earthworms from the contaminated site. In the exposure experiment, exposure time affected expression, but only in the earthworms from the uncontaminated site, suggesting that there is a delay in the metallothionein response of earthworms in this population. In contrast, earthworms from the contaminated site showed higher and constant levels of metallothionein expression at all exposure concentrations and durations. The constant metallothionein expression in earthworms from the contaminated site suggests that inducibility of metallothionein response could be lost in earthworms with metal exposure history. Adaptation of D. octaedra to metal exposure could explain the differences between the populations and explain the persistence of this species in contaminated forest soils.

Smallest known Q value of any nuclear decay: the rare beta;{-} decay of ;{115}In(9/2;{+}) --> ;{115}Sn(3/2;{+}).

The ground-state-to-ground-state Q_{beta;{-}} value of ;{115}In was determined to 497.68(17) keV using a high-precision Penning trap facility at the University of Jyväskylä, Finland. From this, a Q_{beta;{-}} value of 0.35(17) keV was obtained for the rare beta;{-} decay to the first excited state of ;{115}Sn at 497.334(22) keV. The partial half-life was determined to 4.1(6) x 10;{20} yr using ultra low-background gamma-ray spectrometry in an underground laboratory. Theoretical modeling of this 2nd-forbidden unique beta;{-} transition was also undertaken and resulted in Q_{beta;{-}} = 57_{-12};{+19} eV using the measured half-life. The discrepancy between theory and experiment could be attributed to atomic effects enhanced by the low Q value. The present study implies that this transition has the lowest Q value of any known nuclear beta decay.

Efficacy and tolerability of continuous combined hormone replacement therapy in early postmenopausal women.

OBJECTIVE: Continuous combined hormone replacement therapy (ccHRT) based on estradiol valerate (E2V) and medroxyprogesterone acetate (MPA) is effective for relief of menopausal symptoms three years or more after the menopause. This study was undertaken to examine the efficacy and tolerability of ccHRT in early postmenopausal women (last menstrual period 1.3 years before study entry). STUDY DESIGN: This was a 52-week, randomized, double-blind, multinational study of ccHRT comprising three different dose combinations of E2V/MPA in 459 early postmenopausal non-hysterectomized women experiencing 30 or more moderate to severe hot flushes a week and/or vasomotor symptoms requiring treatment. MAIN OUTCOMES MEASURES: The primary endpoint was change in frequency and severity of moderate to severe hot flushes at 12 weeks. Secondary outcome measures included number of bleeding days and evaluation of tolerability. RESULTS: The frequency of hot flushes was reduced by >or=70% after one month (P<0.001 for all doses at week 2 onwards), with little evidence of statistically different dose effects. Severity of flushing was also attenuated by ccHRT. Mean number of bleeding days fell to <1 per 28-day cycle at 52 weeks. Rates of amenorrhoea approached 80-90% at the end of the study, but were significantly lower at several time points with the highest-dose regimen (2 mg E2V + 5 mg MPA) than with the lower-dose options (1 mg E2V + 2.5 mg MPA and 1 mg E2V + 5 mg MPA; P<0.05). Adverse events declined in frequency over time with all regimens but throughout the study were more numerous with the highest-dose regimen than with lower doses (P= 0.0002). CONCLUSIONS: Continuous combined HRT was effective for the relief of climacteric symptoms in early postmenopausal women and was well tolerated.

Bone mineral density and lipid changes during 5 years of follow-up in a study of prevention of breast cancer with toremifene in healthy, high-risk pre- and post-menopausal women.

A double-blind, randomised, placebo-controlled pilot study was initiated to evaluate the feasibility of chemoprevention with toremifene 60 mg/day in healthy women at high risk for breast cancer. Enrolment in the study was terminated earlier than planned because of slow patient accrual, although 13% of patients continued for 5 years. The revised efficacy outcomes were change in bone mineral density (BMD) from baseline at four skeletal sites, plus effects on serum lipids. In premenopausal women there was a trend for sustained increase in BMD during toremifene therapy after year 1 in lumbar spine. In postmenopausal women, toremifene had little or no effect on BMD trends. Levels of total and low-density lipoprotein (LDL) cholesterol were largely unchanged from baseline in premenopausal women treated with toremifene but were often slightly lower than in the placebo group during follow-up. Total and LDL cholesterol levels declined slightly from baseline in the postmenopausal women and were, at several points during the first 3 years, significantly lower than in the corresponding placebo group (p < 0.01). We conclude that: (a) assessment of toremifene 60 mg/day in chemoprevention will require further clinical trials; (b) toremifene 60 mg/day has no substantive negative effects on BMD in pre- or postmenopausal women and may exert a minor favourable influence (in particular, the effects of toremifene 60 mg/day on BMD in premenopausal women may make the drug an attractive alternative to tamoxifen 20 mg/day for that patient subset); (c) lipid effects of toremifene 60 mg/day are, at minimum, neutral and may be modestly favourable for reducing cardiovascular risk.

Endometrial safety and tolerability of triphasic sequential hormone replacement estradiol valerate/medroxyprogesterone acetate therapy regimen.

OBJECTIVE: Two randomized comparative multicenter studies were conducted to establish the endometrial safety and tolerability of a triphasic sequential hormone replacement estradiol valerate/medroxyprogesterone acetate (E2V/MPA) therapy regimen. METHODS: Study 1 was a randomized, double-blind, clinical phase III study in 399 postmenopausal women, following parallel-group design with two groups. The duration of study treatment was 12 or 13 cycles of 28 days. A double-dummy technique was used to ensure blinding in the study. The investigational drugs were E2V/MPA triphasic and E2V/MPA biphasic (Diviseq and Divina, respectively; Orion Pharma). In study 2, a total of 341 subjects were randomly allocated by computer into two parallel groups receiving either E2V/MPA or estradiol/norethisterone acetate triphasic (E2/NETA, Trisequens; Novo Nordisk A/S) for 12-13 cycles. The study was an open, clinical phase III trial with a randomized, parallel-group design. Endometrial biopsies combined with transvaginal ultrasound were undertaken before and at the end of treatment during the progestogen phase. Bleeding patterns and symptom control were assessed throughout both studies. RESULTS: E2V/MPA triphasic was found to have similar endometrial effects and bleeding patterns to those with E2V/MPA biphasic and E2/NETA triphasic. Climacteric symptoms were relieved as quickly and effectively as with the two comparator treatments. No adverse drug reactions specific to E2V/MPA triphasic were observed. At the end of the study, the proportions of secretory samples were 67.1% for the combined E2V/MPA triphasic groups, 65.6% for the E2V/MPA biphasic group and 71.6% for the E2/NETA triphasic group. One case of hyperplasia occurred in the E2V/MPA triphasic group. Thus the incidence of hyperplasia for the combined groups was 0.33%. CONCLUSIONS: The triphasic E2V/MPA regimen was well tolerated and produced endometrial effects similar to those of the two comparators. Extending estrogen during the so-called treatment-free week with a lower dose of estradiol was effective in controlling vasomotor symptoms.

Expression of mouse 17beta-hydroxysteroid dehydrogenase/17-ketosteroid reductase type 7 in the ovary, uterus, and placenta: localization from implantation to late pregnancy.

Rodent 17beta-hydroxysteroid dehydrogenase/17-ketosteroid reductase type 7 (17HSD/KSR7) catalyzes the conversion of estrone (E1) to estradiol (E2) and is abundantly expressed in the ovaries of pregnant animals in particular. In the present work we demonstrate cell-specific expression of 17HSD/KSR7 in the ovaries, uteri, and placentas of pregnant and nonpregnant mice using in situ hybridization. The results show that mouse 17HSD/KSR7 (m17HSD/KSR7) messenger RNA is distinctly and exclusively expressed in a proportion of corpora lutea (CLs). During pregnancy, expression of m17HSD/KSR7 is most abundant around embryonic day 14.5 (E14.5), when the ovaries are filled with CLs expressing 17HSD/KSR7. In the uterus, m17HSD/KSR7 is first detected on E5.5, when expression surrounds the implantation site on the antimesometrial side. As gestation progresses, m17HSD/KSR7 is expressed in the decidua capsularis on E8 and E9.5, disappearing thereafter from the antimesometrial decidua. On E9 onward, m17HSD/KSR7 messenger RNA expression takes place at the junctional zone of the developing placenta. On E12.5 and E14.5, m17HSD/KSR7 is abundantly expressed in the spongiotrophoblasts, where expression gradually declines toward parturition. In conclusion, m17HSD/KSR7 expression in the CL is related to the life span of the CL. Moreover, spatial and temporal expression of m17HSD/KSR7 in the uterus suggests that locally produced E2 plays a role in implantation and/or decidualization. Finally, the results indicate that mouse placenta is capable of converting E1 to E2 in situ, and that the synthesized E2 may be effective in a paracrine, autocrine, and/or intracrine manner and be involved in placentation.

17Beta-hydroxysteroid dehydrogenases in normal human mammary epithelial cells and breast tissue.

17Beta-hydroxysteroid dehydrogenase activity represents a group of several isoenzymes (17HSDs) that catalyze the interconversion between highly active 17beta-hydroxy- and low activity 17-ketosteroids and thereby regulate the biological activity of sex steroids. The present study was carried out to characterize the expression of 17HSD isoenzymes in human mammary epithelial cells and breast tissue. In normal breast tissues 17HSD types 1 and 2 mRNAs were both evenly expressed in glandular epithelium. In two human mammary epithelial cell lines, mRNAs for 17HSD types 1, 2 and 4 were detected. In enzyme activity measurements only oxidative 17HSD activity, corresponding to either type 2 or type 4 enzyme, was present. The role of 17HSD type 4 in estrogen metabolism was further investigated, using several cell lines originating from various tissues. No correlation between the presence of 17HSD type 4 mRNA and 17HSD activity in different cultured cell lines was detected. Instead, oxidative 17HSD activity appeared in cell lines where 17HSD type 2 was expressed and reductive 17HSD activity was present in cells expressing 17HSD type 1. These data strongly suggest that in mammary epithelial cell lines the oxidative activity is due to type 2 17HSD and that oxidation of 17beta-hydroxysteroids is not the primary activity of the 17HSD type 4 enzyme.

Primary structure of a sperm cell anion exchanger and its messenger ribonucleic acid expression during spermatogenesis.

Chloride/bicarbonate (Cl-/HCO(3)-) exchangers are a family of proteins (anion exchanger [AE] gene family) that regulate many vital cellular processes such as intracellular pH, cell volume, and Cl- concentration. They may also be involved in the regulation of sperm cell motility and acrosome reaction during fertilization, as these two phenomena are bicarbonate dependent, and we have previously shown that a polypeptide immunologically related to erythrocyte band 3 is expressed in mammalian sperm cells. We have now identified this putative sperm cell anion exchanger as the AE2 isoform of this gene family. First, we determined its complete primary structure from the human testis lambda gt 11 cDNA library. The cloned sequence was found to consist of 3896 base pairs (bp) with an open reading frame of 3726 bp, and to be almost identical to the previously published human genomic AE2 sequence. Only four amino acid disparities were found between these two sequences. Second, our in situ hybridization analyses showed that AE2 mRNA is expressed in developing sperm cells, indicating that the cloned sequence corresponds to the sperm cell AE. Our reverse transcription-polymerase chain reaction analyses suggested further that the expression of AE2 mRNA was variable to some extent during the epithelial cell cycle. Strongest expression was observed at stages VII-XIV except for stage X, i.e., when major structural and morphological changes take place. These results suggest that the full-length AE2 isoform regulates HCO(3)- transport in mature sperm cells and thus their motility in vivo.

Several genes encoding ribosomal proteins are over-expressed in prostate-cancer cell lines: confirmation of L7a and L37 over-expression in prostate-cancer tissue samples.

A cDNA library specific for mRNA over-expressed in prostate cancer was generated by subtractive hybridization of transcripts originating from prostatic hyperplasia and cancer tissues. cDNA encoding ribosomal proteins L4, L5, L7a, L23a, L30, L37, S14 and S18 was found to be present among 100 analyzed clones. Levels of ribosomal mRNA were significantly higher at least in one of the prostate-cancer cell lines, LNCaP, DU-145 and PC-3, than in hyperplastic tissue, as determined by slot-blot hybridization. Furthermore, L23a- and S14-transcript levels were significantly elevated in PC-3 cells as compared with those in the normal prostate epithelial cell line PrEC. Generally, dramatic changes in the mRNA content of the ribosomal proteins were not detected, the most evident over-expression being that of L37 mRNA, which was 3.4 times more abundant in LNCaP cells than in hyperplastic prostate tissue. The over-expression of L7a and L37 mRNA was confirmed in prostate-cancer tissue samples by in situ hybridization. Elevated cancer-related expression of L4 and L30 has not been reported, but levels of the other ribosomal proteins are known to be increased in several types of cancers. These results therefore suggest that prostate cancer is comparable with other types of cancers, in that a larger pool of some ribosomal proteins is gained during the transformation process, by an unknown mechanism.

Human 17beta-hydroxysteroid dehydrogenase type 2 messenger ribonucleic acid expression and localization in term placenta and in endometrium during the menstrual cycle.

According to the current hypothesis, 17beta-hydroxysteroid dehydrogenases (17HSDs) regulate the extent of estrogen influence in the endometrium by converting estradiol (E2) locally into a biologically less active sex steroid, estrone (E1), and vice versa. Recently, we have shown that both 17HSD type 1 and type 2 are expressed in the human endometrium, and in the present work, using in situ hybridization, we show that 17HSD type 2 is localized in the glandular epithelial cells as previously shown for the type 1 enzyme, but in contrast to type 1, the expression of type 2 is highest at the end of the cycle. Hence, we hypothesize that the differential expression of the two 17HSD enzymes, with opposite activities in same cell types, could modulate intracellular E2 concentrations during the end of the luteal phase of the menstrual cycle. We further analyzed the expression of 17HSD type 1 and type 2 mRNAs in term human placenta. Expression of 17HSD type 1 mRNA was detected in the syncytiotrophoblasts, and signals for type 2 mRNA were found inside the villi, corresponding to cytotrophoblasts. The expression of 17HSD type 2 in the placenta may serve to maintain the presence of inactive sex steroids and attenuate the formation of biologically potent androgens and estrogens.

Mouse 17 beta-hydroxysteroid dehydrogenase type 2 mRNA is predominantly expressed in hepatocytes and in surface epithelial cells of the gastrointestinal and urinary tracts.

17 beta-Hydroxysteroid dehydrogenase (17HSD) type 2 efficiently catalyzes the conversion of the high activity 17 beta-hydroxy forms of sex steroids into less potent 17-ketosteroids. In the present study in situ hybridization was utilized to analyze the cellular localization of 17HSD type 2 expression in adult male and female mice. The data indicate that 17HSD type 2 mRNA is expressed in several epithelial cell layers, including both absorptive and secretory epithelia as well as protective epithelium. In both males and females, strong expression of 17HSD type 2 was particularly detected in epithelial cells of the gastrointestinal and urinary tracts. The mRNA was expressed in the stratified squamous epithelium of the esophagus, and surface epithelial cells of the stomach, small intestine and colon. The hepatocytes of the liver and the thick limbs of the loops of Henle in the kidneys, as well as the epithelium of the urinary bladder, also showed strong expression of 17HSD type 2 mRNA in both male and female mice. In the genital tracts, low 17HSD type 2 expression was detected in the seminiferous tubules, the uterine epithelial cells and the surface epithelium of the ovary. Expression of the mRNA was also detected in the sebaceous glands of the skin. The results indicate that in both male and female mice, 17HSD type 2 is expressed mainly in the various epithelial cell types of the gastrointestinal and urinary tracts, and therefore suggest a role for the enzyme in steroid inactivation in a range of tissues and cell types not considered as classical sex steroid target tissues.

Ontogeny of 17beta-hydroxysteroid dehydrogenase type 2 mRNA expression in the developing mouse placenta and fetus.

17beta-Hydroxysteroid dehydrogenase type 2 (17HSD type 2) catalyzes the inactivation of estradiol, testosterone and dihydrotestosterone into biologically less active 17-keto forms. Our recent Northern analysis indicated that the enzyme is expressed both in mouse placenta and fetus. The present data indicate that in the placenta the distribution of enzyme expression changes during pregnancy. In the choriovitelline placenta (day 8) 17HSD type 2 was expressed both in mural and polar giant cells. Later, on days 9-12.5, the mRNA was also detected in the junctional zone, and in late gestation (days 14.5-17.5), 17HSD type 2 mRNA was predominantly expressed only at the labyrinth region. In the fetus, 17HSD type 2 expression appears in the liver on day 11. At day 12 the expression was strongly increased in the liver, and at the same time moderate mRNA expression was also detected in the esophagus and intestine. In these tissues, high constitutive expression of 17HSD type 2 was then maintained throughout pregnancy. At later stages of development (days 15-16) the mRNA was, furthermore, detected in epithelial cells of the stomach, tongue, oropharynx and nasopharynx as well as in the kidney. We conclude that the expression pattern of 17HSD type 2 in the developing placenta and fetus suggests a role for the enzyme in maintaining a barrier to the transfer of active 17-hydroxy forms of sex steroids between the fetus and maternal circulation.

The extent of apoptosis is inversely associated with bcl-2 expression in premalignant and malignant breast lesions.

AIMS: In this study we investigated the extent of apoptosis in benign, premalignant and malignant breast lesions and its association with the immunohistochemical expression of bcl-2 oncoprotein. METHODS AND RESULTS: In order to detect apoptotic cells and bodies in tissue sections, the 3'-end DNA labelling method was used. Immunohistochemical staining was performed by using the avidin-biotin-peroxidase complex technique. A monoclonal antibody against bcl-2 oncoprotein was used and the specificity of the antibody was confirmed by immunoblot analysis. According to the results the extent of apoptosis, as determined by the apoptotic index, was lowest in benign ductal hyperplasias and sclerosing adenoses (0.15% and 0.07%, respectively). It was moderately elevated in atypical hyperplasias and in-situ carcinomas (0.20% and 0.40%, respectively) and highest in invasive carcinomas (0.76%). In ductal invasive carcinomas, grade I lesions showed a lower apoptotic index (0.52%) than grade II (0.72%) and grade III (1.17%) carcinomas. The apoptotic index was not significantly lower in lobular (0.82%) than in ductal invasive carcinomas (0.85%). bcl-2 immunohistochemistry was inversely related to the apoptotic index. In all cases studied the inverse association was very strong (P = 0.0004) but it was also present when only carcinomas were analysed (P = 0.01). In benign and atypical hyperplasias, bcl-2 positivity was observed in all cases, but such cases were less frequent in in-situ lesions and in invasive carcinomas. CONCLUSIONS: The results show that there is an inverse relationship between the extent of apoptosis and bcl-2 expression in breast lesions suggesting that its expression affects the regulation of apoptosis in them.

Cloning of mouse 17beta-hydroxysteroid dehydrogenase type 2, and analysing expression of the mRNAs for types 1, 2, 3, 4 and 5 in mouse embryos and adult tissues.

17beta-Hydroxysteroid dehydrogenases (17HSDs) are responsible for the conversion of low-activity sex steroids to more potent forms, and vice versa. 17HSD activity is essential for the biosynthesis of sex steroids in the gonads, and it is also one of the key factors regulating the availability of active ligands for sex-steroid receptors in various extragonadal tissues. In this study, we have characterized mouse 17HSD type 2 cDNA, and analysed the relative expression of 17HSD types 1, 2, 3, 4 and 5 mRNAs in mouse embryos and adult male and female tissues. The cDNA characterized has a open reading frame of 1146 bp, and encodes a protein of 381 amino acids with a predicted molecular mass of 41837 kDa. Northern-blot analysis of adult mouse tissues revealed that, of the different 17HSDs, the type 2 enzyme is most abundantly expressed. High expression of the enzyme, which oxidizes both testosterone and oestradiol, in several large organs of both sexes indicates that it is the isoform having the most substantial role in the metabolism of sex steroids. Interestingly, four of the five 17HSD enzymes were also detected by Northern blots of whole mouse embryos, and each of the enzymes showed a unique pattern of expression. The oestradiol-synthesizing type 1 enzyme predominates in early days of development embryonic day 7, but after that the oxidative type 2 enzyme becomes the predominant form of all 17HSDs. The data therefore suggest that there is transient oestradiol production in the early days of embryonic development, after which inactivation of sex steroids predominates in the fetus and placenta.

Iron deficiency anemia, backache, and abdominal pain attacks during sexual intercourse in a 42-year-old woman.

BACKGROUND: Gastrointestinal bleeding is a common diagnostic problem. We describe here a 42-year-old woman who had iron deficiency anemia that went undiagnosed for 8 years. SYMPTOMS AND RESULTS: She had a 'blood spray' when crouching, backache, and abdominal pain attacks during sexual intercourse. Defecography, but neither clinical examination nor endoscopy, demonstrated abnormal mobility of the rectal mucosa associated with other pelvic floor abnormalities. THERAPY: After rectopexy, the bleeding stopped, and the blood values normalized.

Human 17 beta-hydroxysteroid dehydrogenase type 1 and type 2 isoenzymes have opposite activities in cultured cells and characteristic cell- and tissue-specific expression.

17 beta-Hydroxysteroid dehydrogenase (17HSD) isoenzymes catalyse the interconversion between highly active 17 beta-hydroxy- and low-activity 17-keto-steroids and thereby regulate the biological activity of sex steroids. The present study was carried out to characterize 17HSD activity and the expression of 17HSD type 1 and 2 isoenzymes in several human cell types and tissues. The data indicate that in cultured cells the direction of 17HSD activity is exclusively determined by the expression of these distinct isoenzymes. The intracellular environment could not modulate the direction of the enzyme activities in any of the cell types analysed. 17HSD type 1 acts as a reductase converting oestrone into oestradiol, whereas 17HSD type 2 possesses oxidative activity inactivating oestradiol by converting it into oestrone. The data, furthermore, suggest that of the two 17HSD type 1 mRNAs (1.3 and 2.3 kb), expression of the 1.3 kb mRNA is related to enzyme concentration in all the cell types studied. This mRNA is principally expressed in cells of placental and ovarian origin, but is also present in malignant breast epithelial cells. In contrast, 17HSD type 2 is more widely expressed. It is present in several oestradiol-metabolizing tissues as well as in some target cells of sex steroid action. The opposite reaction directions observed in the cultured cells, together with differences in the distribution of the isoenzymes, suggest that type 1 is involved in oestradiol production in females while type 2 plays a role in the inactivation of this sex steroid in peripheral tissues, both in females and in males. However, some examples exist of simultaneous expression of both enzymes in the same cell type or tissue.

Single-dose oral azithromycin versus seven-day doxycycline in the treatment of non-gonococcal urethritis in males.

One hundred and twenty male patients with signs and symptoms compatible with non-gonococcal urethritis were enrolled in a prospective-randomized study to compare the efficacy and safety of a single oral-dose of 1 g azithromycin and a seven-day course of 100 mg doxycycline twice-daily. Clinical examination and culture samples for Chlamydia trachomatis were performed before and approximately 8, 15 and 35 days after starting treatment. Both treatment groups were comprised of 30 chlamydia-positive patients evaluable for efficacy. The eradication rate of C. trachomatis in baseline-positive patients at the first follow-up visit in the azithromycin group was 96% with one persistent case, and 100% in the doxycycline group. After about two weeks, there were two re-occurrences in the azithromycin group, resulting in a cumulative eradication rate of 90% with three culture-positive cases. The corresponding figure in the doxycycline group was still 100%, but there were leucocytes present in the urethral smear of two patients who later proved to be true culture-positive re-occurrences. After about five weeks, there was an additional re-occurrence in the azithromycin group leading to a cumulative eradication rate of 87%, while two re-occurrences in the doxycycline group gave a cumulative eradication rate of 93%. There was no statistically significant difference in efficacy between the single-dose azithromycin and seven-day course of doxycycline in the treatment of patients with chlamydial urethritis.(ABSTRACT TRUNCATED AT 250 WORDS)

Airborne molds and actinomycetes in the work environment of farmer's lung patients in Finland.

Occurrence of molds and actinomycetes in the breathing zone of farmers during the handling of hay, straw, or grain was studied with the use of an Andersen sampler on 35 farms in Finland. On 24 farms there was a person with recently diagnosed farmer's lung disease, and on 11 farms people were free of the disease. The total spore concentration and the concentrations of the spores of Thermoactinomyces (T) vulgaris, Micropolyspora (M) faeni, and Aspergillus (A) umbrosus were statistically significantly higher on the farms of patients with farmer's lung than on the disease-free farms. The mean proportions of the spores of thermotolerant and thermophilic microbes were greater on the farms of farmer's lung patients than on the reference farms. T vulgaris was the predominant actinomycete species. Both T vulgaris and A umbrosus were found on all farms of farmer's lung patients, but M faeni on only about half of such farms. The findings match the results of previous microbiological analyses of Finnish moldy hay and serological analyses of Finnish farmer's lung patients. It seems that T vulgaris, not M faeni, may be the main causative agent of farmer's lung in Finland. The possible etiologic role of A umbrosus requires further investigation. Because the farmers often failed to identify the moldiness of the plant material in contrast to researchers, it might be possible, through training, to improve farmers' ability to identify moldiness.