Identification of long noncoding RNAs with aberrant expression in prostate cancer metastases

Prostate cancer (PCa) is the second-most common cause of male cancer-related death in western industrialized countries, and the emergence of metastases is a key challenge in the treatment of PCa. Accumulating studies have shown that long noncoding RNAs (lncRNAs) play an important role in the regulation of diverse cellular and molecular processes during the development and progression of cancer. Here, we utilized a unique cohort of castration-resistant prostate cancer metastases (mCRPC) and corresponding localized tumors and RNA sequencing (RNA-seq). First, we showed that patient-to-patient variability accounted for most of the variance in lncRNA expression between the samples, suggesting that genomic alterations in the samples are the main drivers of lncRNA expression in PCa metastasis. Subsequently, we identified 27 lncRNAs with differential expression (DE-lncRNAs) between metastases and corresponding primary tumors, suggesting that they are mCRPC-specific lncRNAs. Analyses of potential regulation by transcription factors (TFs) revealed that approximately half of the DE-lncRNAs have at least one binding site for the androgen receptor (AR) in their regulatory regions. In addition, transcription factor enrichment analysis revealed the enrichment of binding sites for PCa-associated TFs, such as FOXA1 and HOXB13, in the regulatory regions of the DE-lncRNAs. In a cohort of prostatectomy-treated prostate tumors, four of the DE-lncRNAs showed association with progression-free time, and two of them (lnc-SCFD2-2, and lnc-R3HCC1L-8) were independent prognostic markers. Our study highlights several mCRPC-specific lncRNAs that might be important in the progression of the disease to the metastatic stage and may also serve as potential biomarkers for aggressive PCa.

Expression and ERG regulation of PIM kinases in prostate cancer

The three oncogenic PIM family kinases have been implicated in the development of prostate cancer (PCa). The aim of this study was to examine the mRNA and protein expression levels of PIM1, PIM2, and PIM3 in PCa and their associations with the MYC and ERG oncogenes. We utilized prostate tissue specimens of normal, benign prostatic hyperplasia (BPH), prostatic intraepithelial neoplasia (PIN), untreated PCa, and castration‐resistant prostate cancer (CRPC) for immunohistochemical (IHC) analysis. In addition, we analyzed data from publicly available mRNA expression and chromatin immunoprecipitation sequencing (ChIP‐Seq) datasets. Our data demonstrated that PIM expression levels are significantly elevated in PCa compared to benign samples. Strikingly, the expression of both PIM1 and PIM2 was further increased in CRPC compared to PCa. We also demonstrated a significant association between upregulated PIM family members and both the ERG and MYC oncoproteins. Interestingly, ERG directly binds to the regulatory regions of all PIM genes and upregulates their expression. Furthermore, ERG suppression with siRNA reduced the expression of PIM in PCa cells. These results provide evidence for cooperation of PIM and the MYC and ERG oncoproteins in PCa development and progression and may help to stratify suitable patients for PIM‐targeted therapies.

AR and ERG drive the expression of prostate cancer specific long noncoding RNAs

Long noncoding RNAs (lncRNAs) play pivotal roles in cancer development and progression, and some function in a highly cancer-specific manner. However, whether the cause of their expression is an outcome of a specific regulatory mechanism or nonspecific transcription induced by genome reorganization in cancer remains largely unknown. Here, we investigated a group of lncRNAs that we previously identified to be aberrantly expressed in prostate cancer (PC), called TPCATs. Our high-throughput real-time PCR experiments were integrated with publicly available RNA-seq and ChIP-seq data and revealed that the expression of a subset of TPCATs is driven by PC-specific transcription factors (TFs), especially androgen receptor (AR) and ETS-related gene (ERG). Our in vitro validations confirmed that AR and ERG regulated a subset of TPCATs, most notably for EPCART. Knockout of EPCART was found to reduce migration and proliferation of the PC cells in vitro. The high expression of EPCART and two other TPCATs (TPCAT-3-174133 and TPCAT-18-31849) were also associated with the biochemical recurrence of PC in prostatectomy patients and were independent prognostic markers. Our findings suggest that the expression of numerous PC-associated lncRNAs is driven by PC-specific mechanisms and not by random cellular events that occur during cancer development. Furthermore, we report three prospective prognostic markers for the early detection of advanced PC and show EPCART to be a functionally relevant lncRNA in PC.

Abstract 4393: Integrative proteomic analysis of prostate cancer reveals distinct regulation of RNA binding proteins during disease progression

To understand the etiology of the disease, and to find novel and more specific drug targets, the driver mutations and expressional changes in prostate cancer have been examined through extensive genomic and transcriptomic characterization. Although significant insight has been gained through these efforts, it is clear that not all molecular alterations influencing the tumor outcome can be captured through these approaches, and that a comprehensive understanding of the molecular events in cancer require thorough investigation of the proteome.

To understand the functional consequences of genetic and transcriptional aberrations in prostate cancer, we aimed to reveal the proteomic changes during disease formation and progression. We performed high throughput mass spectrometry on clinical tissue samples of benign prostatic hyperplasia (BPH), untreated primary prostate cancer (PC) and castration resistant prostate cancer (CRPC). We performed an integrative analysis of the proteomic data with gene copy number, DNA methylation, and RNA expression data from the same samples. Furthermore, proteomic events correlating with the androgen receptor (AR) status of the tumors were analysed.

We uncovered previously unrecognized molecular and pathway events and several novel AR-associated events in the prostate cancer proteomes to study further. We found significant changes in expression of RNA-binding proteins during disease formation and progression. Examining the relationship of RNA binding proteins at the RNA and protein expression level reveal that while many RNA binding proteins exhibit correlation between the expression levels, some seem regulated at the posttranslational level. Two RNA binding proteins, TDP-43 and FUS, which regulated at the protein, but not at RNA level during prostate cancer progression, show opposite behavior during disease progression and correlation with AR status of the tumors. In cultured prostate cancer cell models, we show that these proteins have specific, but divergent interactions with AR at the RNA and protein levels, and that they contribute differentially to AR activity-mediated responses. Thus, these proteins may significantly contribute to prostate cancer molecular evolution and may pinpoint possible targetable pathways in future prostate cancer therapy.

Citation Format: Mauro Scaravilli, Annika Kohvakka, Pekka Ruusuvuori, Ebrahim Afyounian, Matti Nykter, Tapio Visakorpi, Leena Latonen. Integrative proteomic analysis of prostate cancer reveals distinct regulation of RNA binding proteins during disease progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4393.

Abstract 2476: Discovery of an androgen-responsive long noncoding RNA that associates with progression of ERG-overexpressing prostate cancers

Androgen receptor (AR) signaling pathway has an important role in the growth and development of normal prostate, but also in tumorigenesis and progression of prostate cancer (PC). Although the mechanisms of AR signaling have been widely studied and utilized for treatment in advanced PC, the exact role of AR in development of primary PC is unclear. Former studies have found that AR cistrome is reprogrammed during tumorigenesis to bind novel genomic loci by master regulators, including the ETS family transcription factor ERG. While many AR-induced target genes are known, the effect of AR signaling on regulation of long noncoding RNAs (lncRNAs) is poorly understood, especially in the context of PC progression. Previously, we discovered multiple novel PC-associated transcripts (PCATs) to be aberrantly expressed in PC. Here, we evaluated the expression of 39 Tampere PCATs (TPCATs) in 87 radical prostatectomy specimens using high-throughput real-time PCR, and studied their association with time to PSA progression after prostatectomy. Six TPCATs were significantly associated with time to PSA progression, and four of them also associated with extracapsular extension. In addition, we assessed the expression of TPCATs in the TCGA prostate adenocarcinoma cohort, and found many to be correlated with ERG expression. Moreover, publicly available AR ChIP-seq data from PC tumors indicated that several ERG-associated TPCATs had AR-binding sites on their promoters, some of which overlapped with ERG binding sites. Most notably, we found one progression-associated TPCAT that was regulated by AR in an androgen-sensitive manner according to AR siRNA knockdown and DHT stimulation experiments in vitro. The same TPCAT was also highly associated with overexpression of ERG, and further validated to be a highly PC-specific lncRNA that was abundantly expressed in primary PCs. Taken together, these findings give more insight into the role of AR cistrome in the regulation of lncRNAs in primary PC, and introduce a potential novel prognostic marker to be used in early detection of aggressive PC.

Citation Format: Annika Kohvakka, Anastasia Shcherban, Kati K. Kivinummi, Matti Annala, Alfonso Urbanucci, Matti Nykter, Tapio Visakorpi. Discovery of an androgen-responsive long noncoding RNA that associates with progression of ERG-overexpressing prostate cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2476.

Androgen Receptor Deregulation Drives Bromodomain-Mediated Chromatin Alterations in Prostate Cancer

Global changes in chromatin accessibility may drive cancer progression by reprogramming transcription factor (TF) binding. In addition, histone acetylation readers such as bromodomain-containing protein 4 (BRD4) have been shown to associate with these TFs and contribute to aggressive cancers including prostate cancer (PC). Here, we show that chromatin accessibility defines castration-resistant prostate cancer (CRPC). We show that the deregulation of androgen receptor (AR) expression is a driver of chromatin relaxation and that AR/androgen-regulated bromodomain-containing proteins (BRDs) mediate this effect. We also report that BRDs are overexpressed in CRPCs and that ATAD2 and BRD2 have prognostic value. Finally, we developed gene stratification signature (BROMO-10) for bromodomain response and PC prognostication, to inform current and future trials with drugs targeting these processes. Our findings provide a compelling rational for combination therapy targeting bromodomains in selected patients in which BRD-mediated TF binding is enhanced or modified as cancer progresses.

Transcriptome Sequencing Reveals PCAT5 as a Novel ERG-Regulated Long Noncoding RNA in Prostate Cancer

Castration-resistant prostate cancers (CRPC) that arise after the failure of androgen-blocking therapies cause most of the deaths from prostate cancer, intensifying the need to fully understand CRPC pathophysiology. In this study, we characterized the transcriptomic differences between untreated prostate cancer and locally recurrent CRPC. Here, we report the identification of 145 previously unannotated intergenic long noncoding RNA transcripts (lncRNA) or isoforms that are associated with prostate cancer or CRPC. Of the one third of these transcripts that were specific for CRPC, we defined a novel lncRNA termed PCAT5 as a regulatory target for the transcription factor ERG, which is activated in approximately 50% of human prostate cancer. Genome-wide expression analysis of a PCAT5-positive prostate cancer after PCAT5 silencing highlighted alterations in cell proliferation pathways. Strikingly, an in vitro validation of these alterations revealed a complex integrated phenotype affecting cell growth, migration, invasion, colony-forming potential, and apoptosis. Our findings reveal a key molecular determinant of differences between prostate cancer and CRPC at the level of the transcriptome. Furthermore, they establish PCAT5 as a novel oncogenic lncRNA in ERG-positive prostate cancers, with implications for defining CRPC biomarkers and new therapeutic interventions.

Abstract 148: Transcriptome sequencing reveals PCAT5 - new ERG-regulated non-coding transcript in prostate cancer

Background: Prostate cancer (PC) is the second most common cancer among men. Most PC-related deaths are due to invasive tumors that are treated with therapies inhibiting androgen production or androgen receptor (AR) activity. After an initial response, tumors invariably progress to castration resistant prostate cancers (CRPCs) for which no effective cure exists.

Methods and Results: We used transcriptome sequencing to study fresh-frozen tissue specimens from 12 benign prostatic hyperplasias (BPHs), 28 PCs, and 13 CRPCs. Reference-based transcriptome assembly uncovered 145 previously unannotated intergenic PC and CRPC associated long non-coding transcripts (lncRNAs) or isoforms. One third of the transcripts were CRPC-specific. We showed that one of the novel transcripts, Prostate Cancer Associated Transcript 5 (PCAT5), expressed in half of the tumors, was likely regulated by ERG, the key transcription factor in ∼50% of prostate cancers. Genome-wide expression analysis of a PCAT5-positive prostate cancer cell line after PCAT5 knockdown suggested significant alterations in proliferation pathways. In vitro validation of the pathway alterations revealed concordantly dramatic effects in phenotype: stalling of cell growth, migration, invasion, and colony forming potential, and increase in the rate of apoptosis.

Conclusions: We identified the key differences between PC and CRPC in transcriptome level, and validated the oncogenic potential of a novel lncRNA in ERG-positive prostate cancers, PCAT5. Our study presents a number of putative lncRNA biomarkers for CRPC, and opportunities for therapeutic intervention.

Citation Format: Antti Ylipää, Kati Kivinummi, Matti Annala, Annika Kohvakka, Leena Latonen, Mauro Scaravilli, Kimmo Kartasalo, Simo-Pekka Leppänen, Serdar Karakurt, Janne Seppälä, Olli Yli-Harja, Teuvo L.J. Tammela, Wei Zhang, Tapio Visakorpi, Matti Nykter. Transcriptome sequencing reveals PCAT5 - new ERG-regulated non-coding transcript in prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 148. doi:10.1158/1538-7445.AM2015-148

New enveloped dsRNA phage from freshwater habitat

Cystoviridae is a family of bacteriophages with a tri-segmented dsRNA genome enclosed in a tri-layered virion structure. Here, we present a new putative member of the Cystoviridae family, bacteriophage ϕNN. ϕNN was isolated from a Finnish lake in contrast to the previously identified cystoviruses, which originate from various legume samples collected in the USA. The nucleotide sequence of the virus reveals a strong genetic similarity (~80 % for the L-segments, ~55 % for the M-segments and ~84 % for the S-segments) to Pseudomonas phage ϕ6, the type member of the virus family. However, the relationship between ϕNN and other cystoviruses is more distant. In general, proteins located in the internal parts of the virion were more conserved than those exposed on the virion surface, a phenomenon previously reported among eukaryotic dsRNA viruses. Structural models of several putative ϕNN proteins propose that cystoviral structures are highly conserved.

Maintenance of potassium balance during diuretic therapy

The relative efficacies of potassium chloride, amiloride, triamterene and spironolactone in maintaining potassium balance were studied in 40 patients with essential hypertension receiving diuretic therapy. The preparations were administered in random order in a cross-over manner. In 31 patients treated with 50 mg hydrochlorothiazide daily, addition of 1500 mg potassium chloride daily was the weakest and 50 mg spironolactone daily the most effective agent for maintaining serum potassium. Amiloride (5 mg daily) and triamterene (75 mg daily) were less effective and equally so. Similar results were obtained with 9 patients treated with double dosages of the diuretic and supplements. Despite changes in serum potassium, total body potassium remained constant throughout the trial.

Antihypertensive and biochemical effects of different doses of hydrochlorothiazide alone or in combination with triamterene

The antihypertensive and biochemical effects of 25 mg hydrochlorothiazide alone or 50 mg hydrochlorothiazide alone or in combination with triamterene (either 37.5 or 75 mg) once daily were studied in 26 patients with essential hypertension. After a 5-week run-in period the patients were randomized to receive active therapy in a cross-over manner. Each treatment period lasted 3 months. All drugs significantly (p less than 0.01) lowered both systolic and diastolic blood pressure. There were no differences in blood pressure between the medication periods. Serum potassium concentration was slightly lower during all medication periods than during the run-in period. This change was statistically significant (p less than 0.01) only on 50 mg hydrochlorothiazide daily. There were no significant changes in serum magnesium during any of the periods compared to the run-in period. The lowest values were recorded on 50 mg hydrochlorothiazide alone and the highest on 50 mg hydrochlorothiazide plus 75 mg triamterene daily. A slight increase in serum urate was recorded in all medication periods compared to the run-in period. No significant changes were observed in serum total cholesterol, HDL cholesterol or triglycerides between any of the periods. It can be concluded that 25 mg of hydrochlorothiazide is as effective in lowering blood pressure as higher doses of the diuretic. Higher doses of thiazides will in some patients cause adverse metabolic reactions of which the fall in serum potassium and magnesium is effectively hindered by triamterene.

Trends in serum cholesterol and lifestyle indicators in Members of the Finnish Parliament

OBJECTIVE

To examine the extent that public health promotion activity is reflected in life styles of national decision makers, by analysing trends in coronary heart disease risk factors in Members of the Finnish Parliament (MPs).

METHODS

The MPs were studied at the beginning of two subsequent 4-year parliamentary periods between 1991 and 1999. The studies included analyses of serum total cholesterol and high-density lipoprotein (HDL) cholesterol, and a questionnaire about alcohol, smoking and physical activity.

RESULTS

Serum total cholesterol was above the national recommendation of 5.0 mmol/l in 85% of the male MPs and 62% of the female MPs. The mean level of serum total cholesterol increased in female MPs during the 4-year follow-up period (P < 0.05), and male MPs showed an increase in mean HDL cholesterol (P < 0.001). The mean body mass index increased in both male (P < 0.01) and female (P < 0.01) MPs during the same period. Alcohol consumption, smoking and physical activity were unchanged during follow-up.

CONCLUSIONS

From the public health perspective, serum cholesterol is too high in most MPs, and the level in males is above the national average. Both males and females put on weight during the parliamentary period, and male MPs also showed an increase in HDL cholesterol, which may be explained by other lifestyle factors.

Serum cholesterol trends among members of the Finnish parliament

BACKGROUND. Mortality from coronary heart disease in Finland has declined remarkably since the early 1970s. Most of the change has apparently been due to the active national strategy for reduction of serum cholesterol levels. This study was undertaken to estimate to what extent members of the Finnish parliament (MPs) have complied with the national recommendations.

METHODS

Serum total and HDL cholesterol values were measured from MPs of three subsequent parliaments elected in 1987, 1991, and 1995.

RESULTS

From 1987 to 1995, the Finnish MPs showed a reduction of serum total cholesterol that was significant among males (-5.2;%, P < 0.05) but not among females (-6.4%, NS) and was somewhat smaller than the reduction in the general population during 1987 to 1997 (-9.4% among males and -8. 3% among females). The male MPs had a 14% rise in HDL cholesterol (P < 0.01), while among female MPs and in the general population it decreased by 3.1 to 3.8% (all NS). The cholesterol levels of female MPs were altogether a little lower than in the general population. The Finnish MPs tended to have lower total cholesterol levels compared with those reported from Hungarian MPs.

CONCLUSION

The favorable change in the lipid profile of members of the Finnish parliament indicates that they have personally been involved in the national change process. Follow-up of risk factors in national decision-makers is a useful part of comprehensive monitoring of national coronary heart disease prevention activity.

Attitude changes of general practitioners towards lowering LDL cholesterol

BACKGROUND

Clinical studies have demonstrated the benefit of lowering cholesterol in decreasing coronary complications. These results need to be implemented in clinical practice, where an important barrier are the attitudes of physicians.

DESIGN

General practitioners in the city of Helsinki were asked to respond to two questionnaires sent to them by post 12 months apart (1996 and 1997); 284 responses were received in 1996 and 258 in 1997.

METHODS

In addition to brief questions aimed to characterize the responding physician, the questionnaire included four examples of patients: (1) middle-aged man without, or (2) with coronary heart disease (CHD); (3) 70-year-old man with a history of stroke; (4) 70-year-old women with CHD. The physicians were asked at what level of serum low-density-lipoprotein (LDL) cholesterol they usually initiate drug therapy. Comparisons were made longitudinally between 1996 and 1997, as well as between different patients. Analyses are based on the responses of those physicians who reported that they treat atherosclerotic patients (241 and 237 in 1996 and 1997, respectively).

RESULTS

In case 1 (primary prevention), 40.1% of general practitioners in 1996 compared with 52.4% in 1997 (difference +12.3, 95% CI +3.2(-)+20.9, P < 0.01) reported that they would initiate drug therapy at the LDL cholesterol level < 5.0 mmol/l. In case 2 (secondary prevention), 42.0% in 1996 and 54.8 in 1997 (difference +12.8, 95% CI +4.0(-)+21.8, P < 0.01) would initiate drug therapy at the LDL cholesterol level < 4.0 mmol/l. In case 3 (70 year man with stroke), 13.8% in 1996 compared with 30.4% in 1997 (difference +16.6, 95% CI +9.4(-)+24.0, P < 0.01) would initiate drug therapy at the LDL cholesterol level < 4.0 mmol/l. In case 4 (70 year old woman with CHD) 12.8% in 1996 compared with 34.2% in 1997 (difference +21.4%, 95% CI + 13.9(-)+28.7, P < 0.01) would initiate drug therapy at the LDL cholesterol level < 4.0 mmol/l. The physicians' attitudes were significantly more active towards LDL cholesterol lowering both in 1996 and 1997 in case 2 compared with case 1, case 3 or case 4. No difference was observed between case 3 and case 4.

CONCLUSIONS

Between 1996 and 1997 the attitudes of general practitioners towards lowering LDL cholesterol have become significantly more active in all four patient categories. However, the attitudes are still not optimal concerning coronary patients and especially older atherosclerotic patients.

Magnesium and ascorbic acid supplementation in diabetes mellitus

The effect of magnesium (Mg) and ascorbic acid (AA) supplementation on metabolic control was assessed in 56 outpatient diabetics. A 90-day run-in period was followed by two 90-day treatment periods, during which Mg (600 mg/day) and AA (2 g/day) were administered in a randomized double-blind cross-over fashion. A decrease in systolic and diastolic blood pressure (132 +/- 3 vs. 138 +/- 4 and 77 +/- 2 vs. 82 +/- 2 mm Hg; p < 0.05) was observed in insulin-dependent diabetes mellitus subjects during Mg supplementation. No beneficial effect of Mg supplementation was observed on glycemic control, lipids or blood pressure in non-insulin-dependent diabetes mellitus (NIDDM) subjects. AA supplementation improved glycemic control among NIDDM subjects and both fasting blood glucose (9.1 +/- 0.5 vs. 10.1 +/- 0.6 mmol/l; p < 0.05) and HbA1c (8.5 +/- 0.3 vs. 9.3 +/- 0.3%; p < 0.05) improved. Beneficial effects of AA supplementation on cholesterol (5.9 +/- 0.2 vs. 6.2 +/- 0.2 mmol/l; p < 0.05) and triglycerides (2.2 +/- 0.2 vs. 2.5 +/- 0.2; p < 0.05) were also observed in NIDDM subjects. The results suggest that high-dose AA supplementation may have a beneficial effect in NIDDM subjects on both glycemic control and blood lipids.

Carvedilol and atenolol once daily in the treatment of hypertension

Fifty milligrams of carvedilol and 100 mg atenolol were administered in a random order once a day for 2 months to 43 patients with mild to moderate hypertension, in a double-blind crossover study. Blood pressure, heart rate and peripheral blood flow parameters (n = 11) were recorded 2 and 24 h after the drug administration. Supine blood pressure was the same 2 h after both carvedilol and atenolol administration, but carvedilol caused a greater decrease in standing systolic blood pressure 2 h after the administration (P less than 0.05). The heart rate decreased less with carvedilol (P less than 0.01). There was no difference in the effects exerted by the two therapies on systolic blood pressure and the heart rate 24 h after drug administration, but the diastolic blood pressure was higher in patients given carvedilol (92 versus 88 mmHg; P less than 0.05). Forearm blood flow, forearm vascular resistance and calf blood flow did not change significantly with either of the therapies. In conclusion, 50 mg carvedilol once a day is an effective antihypertensive therapy, though its duration of action did not reach that of 100 mg atenolol once a day. Peripheral vasodilation was similar with both therapies.

Maintenance of potassium balance during long-term diuretic therapy in chronic heart failure patients with thiazide-induced hypokalemia: comparison of potassium supplementation with potassium chloride and potassium-sparing agents, amiloride and triamterene

The relative efficacy of potassium chloride, amiloride and triamterene in maintaining potassium and magnesium balance was evaluated in 23 hypokalemic (S-K less than or equal to 3.5 mmol/l) patients with chronic heart failure receiving diuretic therapy. Amiloride and triamterene were administered in a randomized, crossover manner, followed by potassium chloride in an open manner. During a 5-month treatment with hydrochlorothiazide 50 mg twice/day, potassium chloride 1 g twice/day was not as effective as amiloride 5 mg or triamterene 75 mg twice/day in maintaining serum potassium and magnesium and total-body potassium, while amiloride and triamterene seemed to be equally effective. During all three supplementations, a decrease in serum potassium to a hypokalemic level was observed in some patients. The need for higher doses of potassium chloride, amiloride and triamterene was clearly concentrated to the same patients, and correction was easily reached by increasing the respective doses.

Rapid reversal of circadian blood pressure rhythm in shift workers

The blood pressure and heart rates of seven normotensive shift workers were monitored automatically for 24 h with a non-invasive ambulatory method on 3 different days. The first monitoring session took place at the end of an ordinary work period of morning shifts, the second on the first day of a period of night shifts, and the third on the last day of a period of night shifts. The circadian blood pressure rhythm, which showed a normal pattern during the daytime work shift, was totally reversed from the first day of the night shift. The blood pressure rhythm closely followed the sleep-wakefulness cycle. The changes in circadian heart rate rhythm were not as pronounced as those in blood pressure but showed a similar trend.

Response of plasma endorphins, prolactin and catecholamines in women to intense heat in a sauna

Concentrations of immunoreactive beta-endorphin (ir beta-E), corticotropin, cortisol, prolactin and catecholamines in plasma were followed in 11 healthy women during and after exposure to intense heat in a Finnish sauna bath, and compared to those in a similar control situation without exposure to heat. Heat stress significantly increased prolactin and norepinephrine secretion; the percentage increases from the initial plasma concentrations varied from 113 to 1280% (mean 510%) and from 18 to 150% (mean 86%), respectively. The response of the plasma levels of epinephrine, ir beta-E, corticotropin and cortisol to heat exposure was variable. Compared to the control situation, no statistically significant effect of heat exposure on the plasma levels of these hormones was found.

Exercise capacity and hemodynamics in persons aged 20 to 50 years with systemic hypertension treated with diltiazem and atenolol

Hemodynamic responses and exercise capacity were studied during maximal exercise in 25 young hypertensive persons (mean age 40 years) taking placebo, diltiazem (mean 216 mg/day) and atenolol (mean 80 mg/day). The study was a crossover, double-blind, randomized trial, each medication period lasting 2 months. Sitting blood pressure (BP) was 160 +/- 19/109 +/- 8 mm Hg after run-in. Both drugs decreased BP significantly, diltiazem by 10/ 11 mm Hg and atenolol by 16/14 mm Hg (difference not significant between drugs). During exercise there were no differences among patients taking placebo, diltiazem and atenolol in peak workload and rating of perceived exertion. Atenolol significantly attenuated the increase in heart rate, BP and heart rate-BP product at each workload. Diastolic BP during exercise was significantly lower (6 to 10 mm Hg) during diltiazem therapy than during placebo at each workload. Thus, both diltiazem and atenolol decrease rest BP significantly without impairing exercise capacity.

Comparison of the diuretic effects of single dose frusemide/triamterene and hydrochlorothiazide/amiloride in healthy adults

The diuretic and potassium- and magnesium-conserving action of a single dose of frusemide/triamterene, F + TRI (40 mg/50 mg), and hydrochlorothiazide/amiloride, HCT + AMI (50 mg/5 mg), fixed combination preparations were compared in ten healthy adults in a randomised double-blind placebo-controlled study. Urinary volume during 24 hours was significantly higher after HCT + AMI ingestion than after F + TRI. The urine and sodium excretions caused by HCT + AMI lasted markedly longer and were smoother than the short and somewhat unpleasant effects of F + TRI. HCT + AMI also spared potassium and magnesium relatively more effectively than F + TRI.

Role of dietary potassium and magnesium in diuretic-treated patients with cardiac insufficiency

The role of daily dietary intake of potassium and magnesium in the maintenance of potassium balance was studied in 104 digitalized outpatients with chronic cardiac insufficiency receiving 50 mg hydrochlorothiazide twice daily for 6 weeks. The food consumption data were collected once a week by the 24-hour recall method during the 1st, 2nd and 3rd weeks of the investigation. Serum potassium and magnesium values were followed throughout the study, and total body potassium was measured at the end. During the hydrochlorothiazide treatment, potassium and magnesium levels decreased significantly (p less than 0.001). 46% of the patients became hypokalemic (serum potassium less than or equal to 3.5 mmol/l), hypokalemia being more common (64%) in the patients with a concomitant decrease (-0.063 +/- 0.08 mmol/l) in serum magnesium values. Mean intake of potassium and magnesium was 3.4 g and 299 mg in females and 4.2 g and 380 mg in males, respectively. There was no significant difference in the daily intake of potassium and magnesium between the patients becoming hypokalemic and those remaining normokalemic.