Characterizing prostate cancer risk through multi-ancestry genome-wide discovery of 187 novel risk variants

The transferability and clinical value of genetic risk scores (GRSs) across populations remain limited due to an imbalance in genetic studies across ancestrally diverse populations. Here we conducted a multi-ancestry genome-wide association study of 156,319 prostate cancer cases and 788,443 controls of European, African, Asian and Hispanic men, reflecting a 57% increase in the number of non-European cases over previous prostate cancer genome-wide association studies. We identified 187 novel risk variants for prostate cancer, increasing the total number of risk variants to 451. An externally replicated multi-ancestry GRS was associated with risk that ranged from 1.8 (per standard deviation) in African ancestry men to 2.2 in European ancestry men. The GRS was associated with a greater risk of aggressive versus non-aggressive disease in men of African ancestry (P = 0.03). Our study presents novel prostate cancer susceptibility loci and a GRS with effective risk stratification across ancestry groups.

Evidence of Novel Susceptibility Variants for Prostate Cancer and a Multiancestry Polygenic Risk Score Associated with Aggressive Disease in Men of African Ancestry

BACKGROUND

Genetic factors play an important role in prostate cancer (PCa) susceptibility.

OBJECTIVE

To discover common genetic variants contributing to the risk of PCa in men of African ancestry.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a meta-analysis of ten genome-wide association studies consisting of 19378 cases and 61620 controls of African ancestry.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Common genotyped and imputed variants were tested for their association with PCa risk. Novel susceptibility loci were identified and incorporated into a multiancestry polygenic risk score (PRS). The PRS was evaluated for associations with PCa risk and disease aggressiveness.

RESULTS AND LIMITATIONS

Nine novel susceptibility loci for PCa were identified, of which seven were only found or substantially more common in men of African ancestry, including an African-specific stop-gain variant in the prostate-specific gene anoctamin 7 (ANO7). A multiancestry PRS of 278 risk variants conferred strong associations with PCa risk in African ancestry studies (odds ratios [ORs] >3 and >5 for men in the top PRS decile and percentile, respectively). More importantly, compared with men in the 40-60% PRS category, men in the top PRS decile had a significantly higher risk of aggressive PCa (OR = 1.23, 95% confidence interval = 1.10-1.38, p = 4.4 × 10-4).

CONCLUSIONS

This study demonstrates the importance of large-scale genetic studies in men of African ancestry for a better understanding of PCa susceptibility in this high-risk population and suggests a potential clinical utility of PRS in differentiating between the risks of developing aggressive and nonaggressive disease in men of African ancestry.

PATIENT SUMMARY

In this large genetic study in men of African ancestry, we discovered nine novel prostate cancer (PCa) risk variants. We also showed that a multiancestry polygenic risk score was effective in stratifying PCa risk, and was able to differentiate risk of aggressive and nonaggressive disease.

Validation of a multi-ancestry polygenic risk score and age-specific risks of prostate cancer: A meta-analysis within diverse populations

Background

We recently developed a multi-ancestry polygenic risk score (PRS) that effectively stratifies prostate cancer risk across populations. In this study, we validated the performance of the PRS in the multi-ancestry Million Veteran Program and additional independent studies.

Methods

Within each ancestry population, the association of PRS with prostate cancer risk was evaluated separately in each case-control study and then combined in a fixed-effects inverse-variance-weighted meta-analysis. We further assessed the effect modification by age and estimated the age-specific absolute risk of prostate cancer for each ancestry population.

Results

The PRS was evaluated in 31,925 cases and 490,507 controls, including men from European (22,049 cases, 414,249 controls), African (8794 cases, 55,657 controls), and Hispanic (1082 cases, 20,601 controls) populations. Comparing men in the top decile (90-100% of the PRS) to the average 40-60% PRS category, the prostate cancer odds ratio (OR) was 3.8-fold in European ancestry men (95% CI = 3.62-3.96), 2.8-fold in African ancestry men (95% CI = 2.59-3.03), and 3.2-fold in Hispanic men (95% CI = 2.64-3.92). The PRS did not discriminate risk of aggressive versus nonaggressive prostate cancer. However, the OR diminished with advancing age (European ancestry men in the top decile: ≤55 years, OR = 7.11; 55-60 years, OR = 4.26; >70 years, OR = 2.79). Men in the top PRS decile reached 5% absolute prostate cancer risk ~10 years younger than men in the 40-60% PRS category.

Conclusions

Our findings validate the multi-ancestry PRS as an effective prostate cancer risk stratification tool across populations. A clinical study of PRS is warranted to determine whether the PRS could be used for risk-stratified screening and early detection.

Funding

This work was supported by the National Cancer Institute at the National Institutes of Health (grant numbers U19 CA214253 to C.A.H., U01 CA257328 to C.A.H., U19 CA148537 to C.A.H., R01 CA165862 to C.A.H., K99 CA246063 to B.F.D, and T32CA229110 to F.C), the Prostate Cancer Foundation (grants 21YOUN11 to B.F.D. and 20CHAS03 to C.A.H.), the Achievement Rewards for College Scientists Foundation Los Angeles Founder Chapter to B.F.D, and the Million Veteran Program-MVP017. This research has been conducted using the UK Biobank Resource under application number 42195. This research is based on data from the Million Veteran Program, Office of Research and Development, and the Veterans Health Administration. This publication does not represent the views of the Department of Veteran Affairs or the United States Government.

A Rare Germline HOXB13 Variant Contributes to Risk of Prostate Cancer in Men of African Ancestry

A rare African ancestry-specific germline deletion variant in HOXB13 (X285K, rs77179853) was recently reported in Martinican men with early-onset prostate cancer. Given the role of HOXB13 germline variation in prostate cancer, we investigated the association between HOXB13 X285K and prostate cancer risk in a large sample of 22 361 African ancestry men, including 11 688 prostate cancer cases. The risk allele was present only in men of West African ancestry, with an allele frequency in men that ranged from 0.40% in Ghana and 0.31% in Nigeria to 0% in Uganda and South Africa, with a range of frequencies in men with admixed African ancestry from North America and Europe (0-0.26%). HOXB13 X285K was associated with 2.4-fold increased odds of prostate cancer (95% confidence interval [CI] = 1.5-3.9, p = 2 × 10^-4), with greater risk observed for more aggressive and advanced disease (Gleason ≥8: odds ratio [OR] = 4.7, 95% CI = 2.3-9.5, p = 2 × 10^-5; stage T3/T4: OR = 4.5, 95% CI = 2.0-10.0, p = 2 × 10^-4; metastatic disease: OR = 5.1, 95% CI = 1.9-13.7, p = 0.001). We estimated that the allele arose in West Africa 1500-4600 yr ago. Further analysis is needed to understand how the HOXB13 X285K variant impacts the HOXB13 protein and function in the prostate. Understanding who carries this mutation may inform prostate cancer screening in men of West African ancestry. PATIENT SUMMARY: A rare African ancestry-specific germline deletion in HOXB13, found only in men of West African ancestry, was reported to be associated with an increased risk of overall and advanced prostate cancer. Understanding who carries this mutation may help inform screening for prostate cancer in men of West African ancestry.

The implementation and impact of a pilot hydrocele surgery camp for LF-endemic communities in Ethiopia

Background

Ethiopia aims to eliminate lymphatic filariasis by 2020, through a dual approach of mass drug administration to interrupt transmission and morbidity control which includes making hydrocele surgery available in all endemic areas. Locating patients requiring surgery, providing high quality surgeries, and following up patients are all formidable challenges for many resource-challenged or difficult-to-reach communities. To date, hydrocele surgery in Ethiopia has only occurred when a patient has the knowledge, time and resources to travel to regional hospitals. Ethiopia tested the novel approach of using a surgical camp, defined as mobilizing, transporting, providing surgery at a static site, and following up of a large cohort of hydrocele patients within a hospital’s catchment area, to address delays in seeking and receiving care.

Methodology and results

Health extension workers mobilized 252 patients with scrotal swelling from a list of 385 suspected hydrocele cases from seven endemic districts in the region of Beneshangul-Gumuz. Clinical health workers and surgeons confirmed 119 as eligible for surgery. Of 70 additional patients who self-referred, 56 were eligible for surgery. Over a two-week period at a regional hospital, 175 hydrocele excision surgeries were conducted. After discharge three days after surgery, trained clinical health workers followed up with the patients on Day 5, Day 8, Day 14 and 1st-month benchmarks with a randomized follow-up of a selection of patients conducted at 9–12 months. There were no post-operative complications upon discharge at Day 3 and 22, while minor complications occurred (12.6%) between Day 3 and one month. The 9–12 month follow-up found patients self-reported an improvement in quality of life, health and economic status.

Conclusion

A hydrocele surgery camp was effective at providing a large number of quality surgeries in a short time. Using peripheral health workers to mobilize and follow up patients helped address delays in seeking and receiving quality care. Mainstreaming patient mobilization and follow-up into a community health system could be effective in other countries. The camp’s results also influenced two regions in Ethiopia to change their policies in order to offer free hydrocele surgery (including patient transport, consultation, surgery, diagnostic tests and necessary medications).

Hydrocele is a type of scrotal swelling caused by lymphatic filariasis and requires surgery to treat, which can be challenging to address in many endemic countries. Locating and referring patients, providing high quality surgical intervention, and creating a patient follow-up mechanism are all formidable aspects in communities that are often resource challenged and difficult to reach. We explored if the use of a surgical camp setting would be an appropriate intervention to adequately treat a large number of hydrocele patients over a short period, decreasing delays in seeking, reaching and receiving quality surgery for hydrocele. We analyzed each step required to hold the camp including some novel innovations surrounding patient mobilization, referral, and post-surgical quality assurance. The camp was effective at providing a large number of quality surgeries in a short time, with patients self-reporting improvements in quality of life, economic and health status after surgery. The findings from the study may prove useful for countries seeking to implement similar interventions.

Caring for patients in the global programme to eliminate lymphatic filariasis

Clinical lymphatic filariasis (LF) is a debilitating, disfiguring medical condition with severe psychosocial consequences for patients and their families. Addressing these patients’ medical needs is a major component of the global programme to eliminate lymphatic filariasis (GPELF). In the 20 y of providing a minimal package of care many thousands of surgical operations to correct LF hydrocoeles been performed and national programmes in >90% of LF endemic countries have received the training needed to care for their patients. The creation of educational materials detailing appropriate patient care, together with increased funding, have been key catalysts in increasing awareness of clinical LF in recent years. Nevertheless, the implementation of care for these patients has often faced challenges that have led to delays in fully implementing the patient care component of GPELF; these include locating these often stigmatised individuals, maintaining provision of the necessary consumables (e.g. soaps and creams) and maintaining programme support within already overstretched national LF teams. As the LF global programme moves to achieve success by 2030 it will be vital to continue to focus efforts on the care and rehabilitation of those suffering from lymphoedema and hydrocoeles, learning from the experiences of the past 20 y.

Urolithiasis and intracorporeal lithotripsy in 37 Military Hospital, Accra, Ghana

Objective

The purpose of this study was to determine the indications and complications of intracorporeal lithotripsy in our institution.

Methods

Retrospective study carried out at the urology unit of the 37 Military Hospital between 2012-2015. 42 patients had intracorporeal lithotripsy out of 359 patients who had surgery within the period. Records of all patients who had intracorporeal lithotripsy between December 2012 to December 2015 were collected and analysed. An endourology log sheet was used to record data of patient's name, age, sex, indication for operation, location of stone, intraoperative complications, type of instruments/materials used, stone analysis and follow-up dates. All patients between the ages of six months to seventy years presenting with urinary stones diseases within the period were included, whilst patients with urinary stone disease who were managed with open surgery were excluded.Ethical clearance was obtained from the 37 Military Hospital institutional review board.

Results

Lithotripsy constituted 42/359(11.7%) of the methods used in the surgical cases done within the period.The commonest age of presentation was between 31-40 years (26.2%), with a male to female ratio of 2:1. The commonest indications for lithotripsy were pain (92.8%) and hydronephrosis (61.9%). Ureteric stones are more common (50%), followed by renal stones (45%) with the commonest site being the proximal ureter. The commonest procedure was ureteroscopy. Ureteral mucosal injury (5/43) (11.62%), was the commonest intraoperative complication. Postoperative complications were reno-cutaneous fistula (1/43) (2.32%), severe bleeding (1/43) (2.32%) haematuria (4/43) (9.30%).

Conclusion

Pain was the commonest indication for intra-corporeal lithotripsy (92.8%) and also the commonest post-operative complication (9.30%).

Funding

None declared.

Effective Project Management of a Pan-African Cancer Research Network: Men of African Descent and Carcinoma of the Prostate (MADCaP)

Purpose

Health research in low- and middle-income countries can generate novel scientific knowledge and improve clinical care, fostering population health improvements to prevent premature death. Project management is a critical part of the success of this research, applying knowledge, skills, tools, and techniques to accomplish required goals. Here, we describe the development and implementation of tools to support a multifaceted study of prostate cancer in Africa, focusing on building strategic and operational capacity.

Methods

Applying a learning organizational framework, we developed and implemented a project management toolkit (PMT) that includes a management process flowchart, a cyclical center-specific schedule of activities, periodic reporting and communication, and center-specific monitoring and evaluation metrics.

Results

The PMT was successfully deployed during year one of the project with effective component implementation occurring through periodic cycles of dissemination and feedback to local center project managers. A specific evaluation was conducted 1 year after study initiation to obtain enrollment data, evaluate individual quality control management plans, and undertake risk log assessments and follow-up. Pilot data obtained identified areas in which centers required mentoring, strengthening, and capacity development. Strategies were implemented to improve project goals and operational capacity through local problem solving, conducting quality control checks and following compliancy with study aims. Moving forward, centers will perform quarterly evaluations and initiate strengthening measures as required.

Conclusion

The PMT has fostered the development of both strategic and operational capacity across project centers. Investment in project management resources is essential to ensuring high-quality, impactful health research in low- and middle-income countries.

Development, Evaluation, and Implementation of a Pan-African Cancer Research Network: Men of African Descent and Carcinoma of the Prostate

PURPOSE

Cancer of the prostate (CaP) is the leading cancer among men in sub-Saharan Africa (SSA). A substantial proportion of these men with CaP are diagnosed at late (usually incurable) stages, yet little is known about the etiology of CaP in SSA.

METHODS

We established the Men of African Descent and Carcinoma of the Prostate Network, which includes seven SSA centers partnering with five US centers to study the genetics and epidemiology of CaP in SSA. We developed common data elements and instruments, regulatory infrastructure, and biosample collection, processing, and shipping protocols. We tested this infrastructure by collecting epidemiologic, medical record, and genomic data from a total of 311 patients with CaP and 218 matched controls recruited at the seven SSA centers. We extracted genomic DNA from whole blood, buffy coat, or buccal swabs from 265 participants and shipped it to the Center for Inherited Disease Research (Baltimore, MD) and the Centre for Proteomics and Genomics Research (Cape Town, South Africa), where genotypes were generated using the UK Biobank Axiom Array.

RESULTS

We used common instruments for data collection and entered data into the shared database. Double-entered data from pilot participants showed a 95% to 98% concordance rate, suggesting that data can be collected, entered, and stored with a high degree of accuracy. Genotypes were obtained from 95% of tested DNA samples (100% from blood-derived DNA samples) with high concordance across laboratories.

CONCLUSION

We provide approaches that can produce high-quality epidemiologic and genomic data in multicenter studies of cancer in SSA.

MANAGEMENT OF PROSTATE CANCER IN ACCRA, GHANA

INTRODUCTION

Africans living with prostate cancer in Africa face problems of early diagnosis and appropriate treatment.

AIM

To study the clinical incidence of prostate cancer, risk factors, TNM stage, their management and outcomes.

METHODS

A prospective study of Prostate Cancer cases managed at Korle Bu Teaching Hospital and hospitals in Accra, diagnosed by history, abnormal PSA/DRE, physical examination and histologically confirmed by biopsy from 2004 to 2013 was carried out. The cases were TNM staged and managed by approved protocol.

RESULTS

There were 669 cases with a mean age 70±0.045SE years, median Gleason Score of 7, organ confined Prostate Cancer(PC) in 415(62%), locally advanced in 167(25%) and metastatic Prostate Cancer in 87(13%) cases. The cases were followed for median of 10 months to ≥ 84 months. Organ confined cases were managed by: Radical Prostatectomy (RP) 92 (13.8%) with a mortality of 0.3%; brachytherapy 70 (10.5%) with a mortality of 0.1% and External Beam Radiotherapy (EBRT) 155 (23%) with a mortality 0.7%. In all, 98 men constituting (14.1%) cases with a mean age of 75+0.25SE years, life expectancy <10 years were treated by hormonal therapy with a mortality of 1.7%. Twenty cases who were for active surveillance (GS6), PSA <10ng/ml, life expectancy <10 years later all opted for EBRT. Locally advanced cases 25% all had neoadjuvant hormonal therapy then Brachytherapy in 3 (0.4%) mortality 0.15% and EBRT in 64 (9.5%), mortality 0.59%. Hormonal therapy was given in 100 (15%) locally advanced cases, mortality 5%. Metastatic prostate cancer cases (13%) were managed by hormonal therapy, mortality 6%.

CONCLUSION

Improved facilities and dedicated skilled teams led to a significant rise in proportion of organ confined Prostate Cancer from 15.3% to 62% curable by Radical Prostatectomy, brachytherapy or EBRT with longer disease free survival.

The role of ultrasonography in the differentiation of the various types of filaricele due to bancroftian filariasis

OBJECTIVE

(i) To determine the frequencies of urogenital pathologies in men infected with bancroftian filariasis, and (ii) to evaluate the role of ultrasonography (USG) as a diagnostic tool to differentiate between diverse pathologies with different clinical implications. To date, all types of scrotal enlargement resulting from lymphatic filariasis (LF) have been summarized under one term: "filaricele".

PATIENTS AND METHODS

Data were compiled from recruitment phases for field trials in an endemic area for LF in Ghana. 1453 men aged 18 years and above underwent ultrasound examinations of the scrotum. Observation parameters were: Filaria Dance Sign (FDS), dilation of supratesticular lymphatic vessels, thickness of scrotal skin, occurrence and amount of fluid accumulation, echogenicity of the fluid between the layers of the tunica vaginalis, as well as position and homogenicity of testis, epididymis and spermatic cord. In 1132 men, blood samples were taken for parasitological analysis.

RESULTS

In 56% of examined patients, fluid accumulation around the testis was detected (38% subclinical-, 18% clinical stages). Differentiation of the echogenicity of the fluid revealed echo-free hydrocele (EFH) in 47% and echo-dense hydrocele (EDH) in 9%. Patients without hydrocele and subclinical stages had a thinner scrotal skin than those in clinical stages or with lymphscrotum (P < 0.001). In the EDH group the scrotal skin was thicker than in the EFH group (P < 0.001). 1.4% had a lymphscrotum. FDS was detected in 24% of all 1453 volunteers who underwent USG. The number of worm nests correlated with microfilarial load and levels of circulating filarial antigen (P < 0.001; 20% microfilaremic, 48% antigen positive).

CONCLUSION

In an unexpected high number of men (56%) fluid accumulation around the testis was detected by USG of which more than one third (38%) presented with subclinical stages. The study showed that echo-dense and echo-free fluid could be differentiated and that a considerable number of cases had EDH (9%) posing a risk to develop necrotic testis and infertility and therefore requiring immediate surgical intervention. USG thus turned out to be a useful diagnostic technique to differentiate between those cases requiring immediate surgical intervention from those that can be treated with (anti-wolbachial and hyperpermeability reducing) drugs that ameliorate or halt progression of the disease.

Variation in genomic Alu repeat density as a basis for rapid construction of low resolution physical maps of human chromosomes

Human DNA restriction fragments containing high numbers of Alu repeat sequences can be preferentially detected in the presence of other human DNA restriction fragments in DNA from human: rodent somatic cell hybrids when the DNA is fragmented with enzymes that cleave mammalian DNA infrequently. This ability to lower the observed human DNA complexity allowed us to develop an approach to order rapidly somatic hybrid cell lines retaining overlapping human genomic domains. The ordering process also generates a relative physical map of the human fragments detected with Alu probe DNA. This process can generate physical mapping information for human genomic domains as large as an entire chromosome (100,000 kb). The strategy is demonstrated by ordering Alu-detected NotI fragments in a panel of mouse: human hybrid cells that span the entire long arm of human chromosome 17.

The alkylating prazosin analog SZL 49 inactivates both alpha 1A- and alpha 1B-adrenoceptors

A chemically reactive prazosin analog (SZL 49) has been suggested to be an alpha 1A-selective alkylating agent. We found SZL 49 competed for alpha 1-adrenoceptor binding sites with a similar potency (IC50 1 nM) in tissues enriched in both the alpha 1A (hippocampus) and alpha 1B (liver) subtypes. SZL 49 was very difficult to wash out of membrane preparations. However, pretreatment with a high concentration of SZL 49 (0.1 microM) followed by multiple washings resulted in a similar 40-50% loss of alpha 1-adrenoceptor binding sites in both liver and hippocampus. Pretreatment of hippocampal membranes with both SZL and the alpha 1B-selective alkylating agent chloroethylclonidine, sequentially or in combination, caused only a slightly greater inactivation than did either drug alone. Analysis of WB 4101 inhibition curves showed that pretreatment of hippocampal membranes with SZL 49 did not alter the proportions of alpha 1A- and alpha 1B-adrenoceptor subtypes. These data suggest that SZL 49 does not demonstrate in vitro selectivity for either the alpha 1A- or alpha 1B-receptor subtypes.

Role of adenosine receptors in caffeine tolerance

Caffeine is a competitive antagonist at adenosine receptors. Receptor up-regulation during chronic drug treatment has been proposed to be the mechanism of tolerance to the behavioral stimulant effects of caffeine. This study reassessed the role of adenosine receptors in caffeine tolerance. Separate groups of rats were given scheduled access to drinking bottles containing plain tap water or a 0.1% solution of caffeine. Daily drug intake averaged 60-75 mg/kg and resulted in complete tolerance to caffeine-induced stimulation of locomotor activity, which could not be surmounted by increasing the dose of caffeine. 5'-N-ethylcarboxamidoadenosine (0.001-1.0 mg/kg) dose dependently decreased the locomotor activity of caffeine-tolerant rats and their water-treated controls but was 8-fold more potent in the latter group. Caffeine (1.0-10 mg/kg) injected concurrently with 5-N-ethylcarboxamidoadenosine antagonized the decreases in locomotor activity comparably in both groups. Apparent pA2 values for tolerant and control rats also were comparable: 5.05 and 5.11. Thus, the adenosine-antagonist activity of caffeine was undiminished in tolerant rats. The effects of chronic caffeine administration on parameters of adenosine receptor binding and function were measured in cerebral cortex. There were no differences between brain tissue from control and caffeine-treated rats in number and affinity of adenosine binding sites or in receptor-mediated increases (A2 adenosine receptor) and decreases (A1 adenosine receptor) in cAMP accumulation. These results are consistent with theoretical arguments that changes in receptor density should not affect the potency of a competitive antagonist. Experimental evidence and theoretical considerations indicate that up-regulation of adenosine receptors is not the mechanism of tolerance to caffeine-induced stimulation of locomotor activity.

Is adenosine involved in inhibition of forskolin-stimulated cyclic AMP accumulation by caffeine in rat brain?

Caffeine potently inhibited forskolin-stimulated cyclic AMP accumulation in slices of rat cerebral cortex, with an IC50 of 21 +/- 3 microM. Because caffeine competitively blocks adenosine receptors, we examined whether the action of forskolin involved endogenous adenosine or whether caffeine was acting through some novel mechanism. Inhibition by caffeine was observed at all forskolin concentrations examined, although the degree of inhibition decreased at higher concentrations of forskolin. The effect of caffeine was not blocked by the presence of a phosphodiesterase inhibitor but was mimicked by several other methylxanthines. The most potent of these was 8-(p-sulfophenyl)-theophylline, which does not readily cross cell membranes, arguing for an extracellular site of action. Addition of either adenosine or the adenosine uptake blocker dipyridamole potentiated the forskolin response, suggesting that forskolin and adenosine act synergistically in increasing cyclic AMP accumulation. The nonxanthine adenosine receptor antagonist CGS 15943 potently blocked cyclic AMP responses to forskolin, adenosine, and combinations. 3-Isobutyl-1-methylxanthine potently blocked the response to adenosine but caused little or no inhibition of the response to forskolin. Adenosine deaminase (ADA) was added to eliminate contributions of endogenous adenosine. ADA inhibited the response to both adenosine and forskolin; however, 200 times as much enzyme was necessary to inhibit the forskolin response. Inhibition of added ADA with 2'deoxycoformycin dramatically increased the concentration of ADA required to inhibit the adenosine response, without altering the concentration required to inhibit the forskolin response. These results suggest that forskolin-stimulated cyclic AMP accumulation may be partially dependent on endogenous adenosine but that the inhibition observed with caffeine is not solely due to blockade of adenosine receptors.

Caffeine inhibits forskolin-stimulated cyclic AMP accumulation in rat brain

Caffeine potently inhibited forskolin-stimulated cyclic AMP accumulation in slices of rat cerebral cortex. The IC50 for this inhibition was 21 +/- 2.9 microM, and 200 microM caffeine almost completely blocked the forskolin response. Theophylline which is a behavioural stimulant mimicked the effect of caffeine. However, there was only a slight inhibition of the forskolin response by theobromine and IBMX (3-isobutyl-1-methylxanthine), both of which lack behavioral stimulant effects.

Effect of either 2,4-dichlorophenoxyacetic acid or kinetin on production and composition of various fractions from extracellular polysaccharides produced by cotyledon cell suspension cultures of bush bean (Phaseolus vulgaris cv. Contender)

Cotyledon cell suspension cultures of bush bean required 2, 4-dichlorophenoxyacetic acid (2,4-D) for growth. Kinetin was not essential but was required for optimum growth. Both of the regulators were required for optimum production of extracellular polysaccharide (EP).The two regulators had different effects upon the production of three polysaccharide fractions (two pectins and a neutral polysaccharide) isolated from the EP at various stages of the culture cycle.The neutral sugar composition of the pectin fractions from all treatments, including regulator treatments, showed considerable fluctuation during the culture cycle and could be changed markedly by regulator treatments. Changes in composition of the neutral polysaccharide were slight. As a consequence of these results it is now possible to obtain cells differing in the nature of the systems synthesizing, or controlling the synthesis of, the polysaccharides.

Changes in the amount and composition of fractions from extracellular polysaccharide during the culture cycle of cotyledon cell suspension culture of bush bean (Phaseolus vulgaris cv. Contender)

Three different polysaccharides (cold-water-soluble pectin, EDTA-soluble pectin, and neutral polysaccharides) were separated from extracellular polysaccharide produced by bush-bean cotyledon suspension cultures. The different polysaccharides were associated with different phases of the culture cycle. The neutral sugars present in the pectin fractions showed considerable fluctuation during the culture cycle as compared with the rather small changes in the levels of the sugars present in the neutral polysaccharides.

Comparison of growth and extracellular polysaccharide of cotyledon cell suspension cultures of bush bean (Phaseolus vulgaris cv. Contender) grown in coconut-milk medium and synthetic medium

Growth and extracellular polysaccharide (EP) production by cotyledon suspension cultures of bush bean were compared in coconut-milk (CM) medium and synthetic medium. EP was produced at all stages of the culture cycle investigated. The same neutral sugars were present in the EP recovered from both media and the composition showed some changes during the culture cycle. Factors in coconut milk had relatively little effect on the neutral sugar composition of the EP.

[Muscular involvement in rheumatic pelvispondylitis]

The authors explored a group of patients suffering from rheumatic pelvispondylitis from the point of view of muscular lesions: clinical muscular examination, anatomo-pathological investigation of the muscle (optical microscopy, histochemistry), electromyographic investigation, and determination of certain serum and muscle enzymes. Some muscular anomalies were observed, which were predominant in the muscles of the lumbar grooves, although there were some lesions of the quadriceps muscle, with a myogenous appearance, but without inflammation. The clearest anomalies were neurogenic and were present particularly in the muscles of the lumbar grooves.