Fecal microbiota transplantation for the treatment of irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is the most prevalent gastrointestinal disorder in developed countries and reduces patients’ quality of life, hinders their ability to work, and increases health care costs. A growing number of trials have demonstrated an aberrant gut microbiota composition in IBS, also known as ‘gut dysbiosis’. Fecal microbiota transplantation (FMT) has been suggested as a treatment for IBS.

AIM

To assess the efficacy and safety of FMT for the treatment of IBS.

METHODS

We searched Cochrane Central, MEDLINE, EMBASE and Web of Science up to 24 October 2022 for randomised controlled trials (RCTs) investigating the effectiveness of FMT compared to placebo (including autologous FMT) in treating IBS. The primary outcome was the number of patients with improvements of symptoms measured using a validated, global IBS symptoms score. Secondary outcomes were changes in quality-of-life scores, non-serious and serious adverse events. Risk ratios (RR) and corresponding 95%CI were calculated for dichotomous outcomes, as were the mean differences (MD) and 95%CI for continuous outcomes. The Cochrane risk of bias tool was used to assess the quality of the trials. GRADE criteria were used to assess the overall quality of the evidence.

RESULTS

Eight RCTs (484 participants) were included in the review. FMT resulted in no significant benefit in IBS symptoms three months after treatment compared to placebo (RR 1.19, 95%CI: 0.68-2.10). Adverse events were reported in 97 participants in the FMT group and in 45 participants in the placebo group (RR 1.17, 95%CI: 0.63-2.15). One serious adverse event occurred in the FMT group and two in the placebo group (RR 0.42, 95%CI: 0.07-2.60). Endoscopic FMT delivery resulted in a significant improvement in symptoms, while capsules did not. FMT did not improve the quality of life of IBS patients but, instead, appeared to reduce it, albeit non significantly (MD -6.30, 95%CI: -13.39-0.79). The overall quality of the evidence was low due to moderate-high inconsistency, the small number of patients in the studies, and imprecision.

CONCLUSION

We found insufficient evidence to support or refute the use of FMT for IBS. Larger trials are needed.

Loss-of-function variants in founder population highlight atrial myopathy as susceptibility to atrial fibrillation

Background

Atrial fibrillation (AF) is the most common cardiac arrhythmia, and it's associated with genes responsible for cardiac conduction, cardiogenesis, and cardiac structure. The Finnish population has evolved in relative isolation and undergone several bottlenecks, resulting in enrichment of deleterious variants. This facilitates identification of possible causal genes through protein-truncating variants that likely would not have been identified in other populations.

Purpose

To identify novel genetic associations with large effect on AF risk.

Methods

We accessed publicly available summary statistics on AF (ICD-10 code I48) from the FinnGen project R6, containing 28,670 AF cases and 135,821 controls. Then, we annotated all variants in the summary statistics and extracted variants that were predicted with a high effect impact (n=7,113). To account for multiple testing, a false discovery rate cutoff <10% was applied. The UK Biobank was assessed for comparison of allele frequencies. Afterwards, we investigated protein and single-cell RNA expression of the genes of interest in human atrial tissue. Human atrial tissue was obtained by us from 7 individuals and used for mass spectrometry-based proteomics, while single-nucleus RNA sequencing (snRNAseq) data from human hearts was acquired by Tucker [1].

Results

In a genome-wide association study (GWAS) focusing on loss-of function (LOF) variation, we report two LOF variants in the structural genes SYNPO2L and CTNNA3 with much higher allele frequencies compared to non-Finnish Europeans (85-fold and 80-fold enrichment, respectively). The variants increase the risk of AF considerably, which is emphasized as the two variants show the highest effect sizes of all GWAS variants ever associated with AF (SYNPO2L; odds ratio [OR] = 2.79, P-value = 1.32x10–8 and CTNNA3; OR = 2.43, P-value = 9.40x10–7), exceeding that of most clinical risk factors. We accessed phenome-wide association study (PheWAS) results on both variants. There was no association with other phenotypes for the SYNPO2L variant whereas the CTNNA3 variant showed suggestive association with valvular heart disease (P-value = 2.95x10–5). SYNPO2L and CTNNA3 exhibited high protein and RNA expression levels in atrial tissue and were predominantly expressed in cardiomyocytes (Fig. 1).

Conclusion

We identified novel associations between LOF variation in the structural genes SYNPO2L and CTNNA3 and AF. Our study showed how genetic examination of a European subpopulation facilitates discovery of genetic variants and pathophysiological understanding. The results underline the importance of thoroughly investigating subpopulations as unique variants with large effect sizes can be identified.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): This work was supported by the Research Foundation at Rigshospitalet and the Hallas-Møller Emerging Investigator Novo Nordisk.

Prevalence of Wolff-Parkinson-White syndrome, association with congenital heart disease, and natural history in newborns

Background

Wolff-Parkinson-White (WPW) syndrome is characterized by an accessory electrical pathway between the atria and ventricles. Clinically, the condition can lead to supraventricular tachycardia, and is associated with sudden cardiac death and congenital heart disease. Studies investigating the prevalence, associated structural cardiac abnormalities, and natural history in newborns are few.

Purpose

To determine the prevalence of WPW syndrome in newborns, describe electrocardiographic and echocardiographic characteristics, and the natural history in childhood.

Methods

Electrocardiograms (ECGs) and echocardiograms of newborns (aged 0–30 days) from a large, prospective, general population study were included. WPW cases were identified through manual evaluation of outliers in PR-interval, QRS-duration, and QRS axis. Newborns with suspected or confirmed pre-excitation on their initial ECG were offered a cardiac follow-up. Localization of the accessory pathway was assessed utilizing a QRS polarity algorithm. Cases were matched 1:4 to controls by age, sex, weight and gestational age.

Results

Among the 17,489 ECGs we identified 17 (76% boys) newborns with definite WPW syndrome consistent with a prevalence of 0.1%. At follow-up (available in 12/17 children) at a mean age of three years, the WPW pattern remained in three children while the ECG had normalized in the nine remaining children. The median values for the newborns' heart rate, PR-interval, QRS-duration, QTc(Bazett), the maximum amplitude in R-V1 and S-V6 in cases and controls were 131 vs. 142 beats per minute, 80 vs. 96 ms, 74 vs. 56 ms, 449 vs. 420 ms, 1,562 vs. 1,028 μV and 546 vs. 693 μV, respectively (all p<0.05, Figure 1). The newborns' QRS axis, max amplitude in S-V1 and R-V6 did not differ among cases and controls (all p>0.05). Echocardiographic measurements of the newborns' left ventricular diameter and function, wall thicknesses, and doppler measurements of trans-mitral- and main pulmonary artery blood flow did not differ significantly between cases and controls (all p>0.05). The accessory electrical pathway was left-sided in 14 (82%) of the newborns. One newborn had significant mitral regurgitation while all other newborns had structurally normal hearts; there were no cases of Ebstein's anomaly.

Conclusion

The prevalence of WPW syndrome in our cohort of asymptomatic newborns was 0.1%. The syndrome was more frequent in boys, the accessory pathway was mostly left-sided, and was associated with changes in several ECG parameters, but generally not associated with structural heart disease. A striking observation was, that the WPW pattern in the majority of children could not be reproduced on follow-up ECGs at a mean age of three years, suggesting either that the ECG pattern is intermittent, or normalization occurs.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The Danish Heart Foundation

Left ventricular non-compaction in childhood: echocardiographic follow-up and prevalence in first-degree relatives

Introduction

Left ventricular non-compaction (LVNC) is characterized by excessive trabeculations of the left ventricular wall. LVNC may be associated with reduced systolic function but is also found in individuals with normal ventricular function. It is debated whether LVNC is only congenital or may develop later in life. The clinical importance and heredity of LVNC with normal systolic function is unclear.

Purpose

We aimed to describe the echocardiographic development of the left ventricular function and LVNC pattern in children with LVNC, diagnosed at birth, at follow-up at the age of 2–4 years compared to matched controls. Additionally, we aimed to describe the prevalence of LVNC in first-degree relatives.

Methods

A follow-up transthoracic echocardiography was performed in children at 2–4 years of age, diagnosed with LVNC at birth (<30 days) as part of a large population study of newborns (n>25,000). Cases were matched 1:4 to controls on mother's age at delivery, parity, and age of the child at follow-up. First-degree relatives (parents, siblings and half-siblings) of cases and controls were also offered inclusion. LVNC was defined as a ratio of non-compact to compact myocardium of ≥2 in at least one left ventricular segment measured in end-diastole perpendicular to the left ventricular cavity.

Results

13 of the 16 children diagnosed with LVNC at birth (median age 3 (interquartile range (IQR) 3–4) years, 77% male) and 52 children without LVNC at birth (age 4 (IQR 3–4) years, 88% male) was reevaluated as well as 36 first-degree relatives of children with LVNC (age 30 (IQR 4–37) years, 44% male) and 136 first-degree relatives of children without LVNC (age 32 (IQR 10–38) years, 50% male). In probands, the number of segments fulfilling criteria (8% vs. 13%, p=0.4) and systolic function, measured as fractional shortening (FS), were unchanged from birth to follow-up, and within normal range (29% vs. 30%, p=0.34). However, at follow-up, FS was significantly lower in probands compared with matched controls (30% vs. 33%, p<0.001). Criteria of LVNC was fulfilled in 11 out of 36 (31%) first-degree relatives to probands, whereas none of the first-degree relatives of children without LVNC fulfilled criteria of LVNC (p<0.001). FS was significantly lower in first-degree relatives of probands fulfilling criteria of LVNC compared to first-degree relatives of matched controls (30% vs. 32%, p=0.01).

Conclusion

Children with LVNC diagnosed neonatally as part of a population study still had a reduced systolic function when compared to controls but showed no further progression of left ventricular dysfunction or extent of trabeculation at the age of 2–4 years. One third of first-degree relatives to children diagnosed with LVNC with a preserved systolic function, fulfilled criteria for LVNC and had reduced systolic function compared to controls. These findings strongly support family-screening and clinical follow-up of children with LVNC.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Novo Nordisk FoundationHerlev-Gentofte Hospital Internal Funding

Family screening in dilated cardiomyopathy-qualifying screening and need for follow-up

Background

Guidelines recommend family screening in dilated cardiomyopathy to uncover pre-symptomatic disease to improve morbidity and mortality through early treatment. According to patterns of inheritance and incomplete penetrance, less than half of relatives to dilated cardiomyopathy probands will develop disease, but so far, no guidelines provide recommendations on the frequency and intensity of follow-up screening.

Purpose

To investigate the prevalence and incidence and identify predictors of developing familial dilated cardiomyopathy (FDC) in relatives participating in family screening.

Methods

The study was an observational, longitudinal cohort study of families screened and followed from 2006 to 2020, at a regional assembly of clinics for inherited cardiomyopathies in Denmark.

Results

We included 211 families totaling 774 subjects (n=563 relatives, 47% women). At baseline, 124 relatives (22%) were diagnosed with dilated cardiomyopathy, while 43 relatives (8%) not fulfilling FDC criteria were found to carry class IV to V genetic variants. Thus, the combined clinical and genetic yield of screening was 30% at baseline. Relatives not fulfilling diagnostic criteria for FDC at baseline (n=439), were stratified into four groups based on results from genetic screening and clinical work-up at baseline (Figure 1). The risk of developing FDC during follow-up was strongly associated with this classification (see figure 1 and 2). The highest risk of developing FDC was observed in relatives carrying class IV to V genetic variants (n=43, age-adjusted incidence rate of 10% per person-year), while none of the subjects identified as non-carriers of family variants developed disease (n=58). In subjects sub-grouped according to baseline-findings on ECG and echocardiography, relatives with abnormal (n=70) vs normal (n=268) findings had markedly higher incidence rates of FDC (overall 4.7% vs 0.4% per person-year), regardless of age-group (Figures 1 and 2). The relatives with abnormal ECG and/or echocardiographic findings at baseline had a (age-group-adjusted) hazard ratio of 12.9 (CI: 4.8 to 35.1, p<0.001), when compared to relatives with normal findings.

Conclusion

Family screening identified a genetic predisposition to or overt FDC in 30% of screened relatives at baseline. In relatives not fulfilling criteria for FDC at baseline, findings from genetic testing and/or non-diagnostic findings on echocardiography and/or ECG were strongly associated with progression to disease. Importantly, relatives with normal genetic or objective findings had a low incidence rate and overall risk of developing FDC. Thus, baseline-screening identified a large proportion of relatives, in whom follow-up can be considered to be reduced allowing focused follow-up of relatives at higher risk of progression.

Funding Acknowledgement

Type of funding sources: None.

Arrhythmogenic right ventricular cardiomyopathy – evolution of electrocardiographic markers during long-term follow-up prior to ascertainment of diagnosis

Background

Depolarization and repolarization abnormalities are part of the diagnostic Task Force Criteria of 2010 (TFC2010) for arrhythmogenic right ventricular cardiomyopathy (ARVC). These abnormalities are thought to be progressive but have also been described as dynamic and sometimes reversible. Evolution of ECG abnormalities prior to clinical ARVC diagnosis is poorly studied.

Objective

To assess the evolution of ECG depolarization and repolarization characteristics in patients with ARVC prior to diagnosis and to identify markers of disease progression at a preclinical stage.

Methods

353 patients with definite ARVC from Sweden, Denmark, the Netherlands and Canada with at least one 12-lead digital ECG (65% males, 67% probands, 56% mutation carriers, median age at diagnosis 42 [IQR 29–53] years and median age at first ECG 44 [30–55] years) were included. Digital ECGs were extracted from regional ECG archives. ECGs with left bundle branch block, ventricular pacing or recorded either prior to 15 years of age or after heart transplantation were excluded. Remaining 6,871 ECGs were digitally processed and automatically analysed using the Glasgow algorithm. Median values for overall QRS duration, terminal activation delay (TAD) in lead V1 as well as amplitudes of QRS-T-components in precordial leads per patient per year were used for analyses and graphically represented using Lowess smoothing with cubic splines (Figure 1). Blue lines indicate smoothed conditional mean with 95% confidence interval (shadow). Time “0” (red line) indicates the time when TFC2010 were fulfilled for definite diagnosis.

A database of 18,564 anonymized digital ECGs (58% males, median age at latest ECG 41 years [IQR 32–52]) who were in contact with health care during 2020–2021 was processed using the same exclusion criteria and signal-processing methodology as in the ARVC group and used as a reference (black line).

Results

TAD in lead V1 and overall QRS duration demonstrated a significant increase years before ARVC diagnosis, and significant reductions were seen in QRS-T voltages measured as R wave amplitude, QRS amplitude (the absolute sum of R wave and S wave), and T wave amplitude (Table 1 and Figure 1). The changes were seen in all precordial leads, not only the right-sided, and visually diverging from the controls.

Conclusion

Development of the ARVC ECG phenotype started several years before diagnosis and continued afterwards. QRS duration and TAD increased, QRS voltages decrease, and T wave amplitude decreased eventually leading to T wave inversion. These changes might be visually assessed but also measured with available ECG software. These findings may be clinically useful in the screening and follow-up of ARVC relatives.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Governmental funding of clinical research (ALF), Region Ostergotland, Sweden.The Swedish Heart-Lung Foundation.

The impact of perinatal factors on the neonatal electrocardiogram

Background

Myocardial development is still incomplete by the time of birth making the cardiomyocyte vulnerable in the perinatal period. However, little is known on whether perinatal factors affect the neonatal electrocardiogram, and if so, to what degree these effects persist in the neonatal period.

Purpose

To investigate the impact of maternal and perinatal factors on the neonatal electrocardiogram in a large unselected cohort of neonates.

Methods

In a multicentre, prospective, population-based cohort study, neonates underwent cardiac evaluation during the first month of life. Electrocardiograms and echocardiograms were obtained and systematically analysed. Medical and demographic information on the parents, pregnancy, and birth-related factors were registered, and the following perinatal risk factors were evaluated: maternal comorbidities, maternal BMI ≥25, use of assisted reproduction technology, parity, (preterm) premature rupture of membranes, placental disorders, abnormal foetus presentation, induction of labour with synthetic hormone, instrumental induction, administration of nitrous oxide, epidural/spinal administration, labour ≥24h, pushing stage ≥1h, Caesarean section, and instrumental delivery.

Results

A total of 15,928 singletons with normal echocardiograms were included (52% boys; median age at examination 11 days). The neonates were divided into groups by accumulated number of perinatal risk factors: 0 (n=1,587), 1 (n=3,718), 2 (n=4,026), 3–4 (n=4,998), and ≥5 (n=1,197), and differences in ECG parameters between the groups were analysed. Heart rate, QRS axis, uncorrected QT interval, QTcBazett, QTcFridericia, and maximum amplitudes in R-V1 and R-V6 differed across the five subgroups (all p<0.05). We observed a cumulative effect of perinatal risk factors on ECG parameters with increasing left-shift in the QRS axis, prolongation of the QT interval, and increasing amplitudes in R-V1 and R-V6. The subgroup with ≥5 perinatal risk factors differed the most, and absolute differences between this subgroup and neonates without any perinatal risk factors were 7.6% in maximum amplitudes in R-V6 (940 vs. 874 μV, p<0.01), 4.3% in R-V1 (1,201 vs. 1,152 μV, p<0.05), 5.1% in the QRS axis (111 vs 117°, p<0.0001) and 0.8% in QTcFridericia (366 vs. 363 ms, p<0.01).

Conclusion

We observed a cumulative effect of perinatal risk factors including a significantly more left-shifted QRS axis, increased values of the QT interval, and higher amplitudes in R-V1 and R-V6 in the subgroup with ≥5 perinatal risk factors. These findings suggest a relatively lower right ventricular dominance pattern, discrete prolongation of the QT interval and increased myocardial mass of the right ventricle in neonates exposed to multiple perinatal risk factors. However, the absolute differences in ECG parameters were relatively small. These findings may be useful for identification of neonates with increased cardiovascular risk.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Department of Cardiology, Herlev-Gentofte Hospital, Internal Funding

Successful treatment of Clostridioidesdifficile infection with single-donorfaecal microbiota transplantation capsules

INTRODUCTION

Treatment of recurrent Clostridioides difficile infection with faecal microbiota transplantation (FMT) is highly effective and is the recommended treatment following a second recurrence. The cure rates of capsule treatment are high (82%-88%). Whether using multi-donor or single-donor FMT capsules affects cure rates remains incompletely understood.

METHODS

A retrospective case series of patients with recurrent, refractory or fulminant C. difficile infection treated for three days with single-donor FMT capsules from October to December 2020 was conducted. The aim of the study was to investigate the clinical efficacy (cure rate) of the treatment and to compare cure rates with previously reported cure rates of treatment with multi-donor FMT capsules produced at the same stool bank. Clinical cure was defined as absence of diarrhoea or diarrhoea with a C. difficile negative stool sample eight weeks after treatment.

RESULTS

Clinical cure was observed in 15 of the 18 (83.3%) patients following three days of FMT capsule treatment. Cure rates were comparable (p = 1.0) to previously reported cure rates (88.9%) of multi-donor FMT capsule treatment of recurrent C. difficile infection.

CONCLUSIONS

Three days of single-donor FMT capsule treatment was effective and safe in the treatment of recurrent, refractory and fulminant C. difficile infection with cure rates comparable to those of multi-donor FMT capsule treatment.

FUNDING

This work was supported by the Danish Innovation Fund under Grant 7076-00129B, MICROHEALTH. The funders had no role in the study design, data collection or analysis, the decision to publish, or in the preparation of the manuscript. The FMT capsules from the Aleris-Hamlet FMT Stool Bank were supplied to the Copenhagen University Hospital - Hvidovre Hospital free of charge.

TRIAL REGISTRATION

not relevant.

Engraftment of strictly anaerobic oxygen-sensitive bacteria in irritable bowel syndrome patients following fecal microbiota transplantation does not improve symptoms

Dysbiosis of the gut microbiome has been correlated with irritable bowel syndrome (IBS). Fecal microbiota transplantation (FMT) is being explored as a therapeutic option. Little is known of the mechanisms of engraftment of microbes following FMT and whether the engraftment of certain microbes correlate with clinical improvement in IBS. Microbiome data, from a previously reported placebo-controlled trial of treatment of IBS with FMT or placebo capsules, were used to investigate microbial engraftment 15 days, 1, 3 and 6 months after treatment through assessment of gains, losses and changes in abundance of amplicon sequence variants (ASVs) and microbial diversity (CHAO-1 richness) between the FMT group and the placebo group. These data were compared to changes in IBS Symptom Severity Scores (IBS-SSS). Twelve days of treatment with 25 daily multi-donor FMT capsules induced significant short- and long-term changes in the recipients' microbiomes for at least 6 months, with persistent engraftment of a variety of anaerobic bacteria from keystone genera, such as Faecalibacterium, Prevotella and Bacteroides and increased microbial diversity, particularly in patients with low initial diversity. FMT recipients lost ASVs after treatment, which was seen to a much lesser extent in the placebo group. No ASVs increased to a greater extent between FMT responders and non-responders following treatment. Major long-term changes, lasting for at least 6 months, in the gut microbiomes of IBS patients are seen following treatment with FMT capsules. None of these changes correlated with clinical improvement. The relationship between the microbiome and the etiology of IBS still remains unsolved.

The effect of faecal microbiota transplantation on abdominal pain, stool frequency, and stool form in patients with moderate-to-severe irritable bowel syndrome: results from a randomised, double-blind, placebo-controlled study

BACKGROUND

Irritable bowel syndrome (IBS) is associated with intestinal dysbiosis. Therefore, faecal microbiota transplantation (FMT) has been hypothesised to have a positive effect in patients with IBS. In this study, we analysed previously unexamined data from our randomised, double-blind, placebo-controlled study (trial registration number NCT02788071). The objective was to evaluate the effect of FMT on abdominal pain, stool frequency, and stool form.

METHOD

The study included 52 adult patients with moderate-to-severe IBS assigned randomly to treatment with FMT capsules or placebo capsules (1:1) for 12 days. The patients were followed for a total of six months, during which they kept a daily symptom diary tracking their abdominal pain on a scale from 0-10 and their bowel movements using the Bristol Stool Form Scale (BSFS). Diary data were not collected before treatment start.

RESULTS

A statistically significant improvement in stool frequency was found in the FMT group from during treatment to post-treatment and 1 month. No statistically significant differences were found between groups at any time during the study for any of abdominal pain, stool frequency, and stool form (as measured by weighted stool score).

CONCLUSION

In this analysis of results from a randomised, double-blind, placebo-controlled study, we found no clinically beneficial effect of FMT on abdominal pain, stool frequency, or stool form. However, since the current literature on the potential role of FMT in treating IBS shows conflicting results, further studies are required. To assess treatment efficacy, we recommend future studies to include daily symptom diaries both before and after treatment intervention.

P2821Diagnostic yield and outcomes of systematic work-up of aborted sudden cardiac death victims and their relatives

Introduction

Cardiac arrest can be the first manifestation of most inherited cardiac diseases. This motivates the international guidelines recommending screening of relatives of cardiac arrest survivors (aSCD) if an inherited cardiac disorder might have caused the cardiac arrest.

Purpose

To assess the presence of inheritable cardiac diseases in cardiac arrest survivors and their relatives.

Methods

In this retrospective study we consecutively included cardiac arrest survivors (probands) and their relatives referred to our tertiary referral center from 2005 to 2018. All probands and relatives underwent a systematic screening protocol. Data were retrieved from medical files. Only probands with non-ischemic heart disease were included.

Results

We included 155 probands (41±16 years old, 94 (61%) male) and 284 relatives (36±19 years old, 144 (51%) male). We identified an inheritable cardiac disease in 70 (45%) probands, most frequently cardiomyopathies (41, 26%) followed by channelopathies (27, 17%) (figure). A borderline diagnosis was found in 32 (21%) probands. In the relatives, an inheritable diagnosis was identified in 38 (13%) individuals, most frequently channelopathies (23, 8%), and a borderline diagnosis was identified in 33 (12%) individuals.

Conclusion

Clinical assessment of aSCD cases on a non-ischemic basis identified an inheritable cardiac disease as the most likely etiology in almost half of the probands and in 13% of the relatives.

P337Natural history, reversibility and arrhythmias associated with truncating titin variants in dilated cardiomyopathy

Background

Truncating genetic variants in titin (TTNtv) are identified in 15–25% of patients with primary dilated cardiomyopathy (DCM). Previous genotype/phenotype studies have reported conflicting results regarding disease severity and pathologic features associated with TTNtv.

Purpose

To investigate the natural history, reversibility and burden of arrhythmias associated with TTNtv in a Danish cohort with long-term follow-up.

Methods

Patients with DCM, recruited from two Danish tertiary centers, were included based on the presence of a TTNtv in a cardiac expressed titin exon. Data on patients' medical history including symptoms, demography, family history, comorbidities, treatment, ECG features, and echocardiograms were registered. Outcome data including all-cause mortality, need of heart transplantation (HTX) or left ventricular assist device (LVAD), and presence of ventricular and supraventricular arrhythmias were registered. Left ventricular reverse remodeling (LVRR) was defined as an absolute increase in left ventricular ejection fraction (LVEF) ≥10% points or normalization.

Results

A total of 104 patients (71 men, 69%; 72 probands) with definite TTNtv-DCM were included. The mean age at DCM diagnosis was (mean±SD) 45±13 years (43±13 for men; 49±14 for women, p<0.04) and median follow-up was 8.1 years. The mean LVEF was 28±13% at time of diagnosis (26±12% for men; 30±13% for women, p=0.173). During follow-up, 31 patients (30%; 24 men) died or needed HTX/LVAD. Medical therapy was associated with LVRR in 79% of patients 3.6 years after diagnosis. LVRR was maintained long-term in 64% of patients. Women had a better response to medical therapy compared to men (mean LVEF increase 19%; vs 15% in men, p<0.04). Atrial fibrillation/flutter was observed in 40% of patients and ventricular arrhythmias in 23% of patients. Men had an earlier occurrence of both supraventricular and ventricular arrhythmias (p=0.005) with half of the men having experienced an arrhythmia at the age of 54 years.

Freedom from arrhythmias with age

Conclusion

TTNtv leads to a DCM phenotype associated with a marked gender-difference in age at DCM diagnosis and high burden of both supraventricular and ventricular arrhythmias. Importantly, the DCM-TTNtv phenotype was associated with a high degree of reversibility of systolic function following medical therapy.

P2830Clinical and genetic findings in relatives to young sudden cardiac death victims without post-mortem examination (autopsy)

Background

Guidelines recommend clinical assessment of relatives to young sudden cardiac death (SCD) victims (<50 years) to protect the surviving relatives by pre-symptomatic interventions, in case the SCD was due to an inherited cardiac disorder. The etiology is an inherited cardiac disease in about 50% of young SCD cases. The work-up of relatives is generally guided by findings in the SCD victim. If post-mortem examinations (autopsies) have not been performed the work-up of relatives is challenged. The diagnostic hit-ratio of screening of relatives under these circumstances is unclear.

Purpose

To assess the diagnostic yield of inherited cardiac diseases of cardiac work-up in relatives of SCD victims, where no autopsy had been performed.

Methods

This retrospective study consecutively included families referred to our tertiary referral centre, specialised in hereditary cardiac diseases, during the period 2005 to 2018 due to SCD in the family. No autopsy had been performed in any of the SCD victims. The relatives underwent standard cardiac work-up according to guidelines. Based on the findings in the relatives the families were categorised into: 1) definite diagnosis, 2) borderline diagnosis or 3) undiagnosed.

Results

We assessed 149 relatives (43±16 age, 48% men) to 84 SCD un-autopsied cases (44±11 age, 79% men). In 11 (13%) families a definite diagnosis was established, in 8 (10%) families a borderline diagnosis was found and the remaining 65 (77%) families remained undiagnosed. The most common diagnosis was premature IHD (36%) followed by cardiomyopathies (27%) and channelopathies (27%). A disease-causing mutation was identified in 3 families out of 15 genetically examined families.

Conclusion

Systematic cardiac work-up of relatives to not-autopsied SCD victims, revealed a definite hereditary cardiac disease in 13% of the referred families, and a borderline diagnosis in additionally 10% of the families. Despite a reduced diagnostic yield in family members of non-autopsied SCD victims, work-up of relatives is clearly still justified.

Multidonor FMT capsules improve symptoms and decrease fecal calprotectin in ulcerative colitis patients while treated - an open-label pilot study

Background: Growing evidence indicates that gut dysbiosis is a factor in the pathogenesis of ulcerative colitis (UC). Fecal microbiota transplantation (FMT) appears to be promising in inducing UC remission, but there are no reports regarding administration using capsules. Methods: Seven patients with active UC, aged 27-50 years, were treated with 25 multidonor FMT capsules daily for 50 days as a supplement to their standard treatment in an open-label pilot study. The primary objective was to follow symptoms through the Simple Clinical Colitis Activity Index (SCCAI). Secondary objectives were to follow changes in fecal calprotectin and microbial diversity through fecal samples and quality of life through the Inflammatory Bowel Disease Questionnaire (IBDQ). Participants were followed through regular visits for six months. Results: From a median of 6 at baseline, the SCCAI of all participants decreased, with median decreases of 5 (p = .001) and 6 (p = .001) after 4 and 8 weeks, respectively. Three of the seven patients had flare-up/relapse of symptoms after the active treatment period. The median F-calprotectin of ≥1800 mg/kg at baseline decreased significantly during the treatment period, but increased again in the follow-up period. The median IBDQ improved at all visits compared to baseline. The fecal microbiota α-diversity did not increase in the study period compared to baseline. All participants completed the treatment and no serious adverse events were reported. Conclusion: Fifty days of daily multidonor FMT capsules temporarily improved symptoms and health-related life quality and decreased F-calprotectin in patients with active UC.

Faecal microbiota transplantation alters gut microbiota in patients with irritable bowel syndrome: results from a randomised, double-blind placebo-controlled study

OBJECTIVE

IBS is associated with an intestinal dysbiosis and faecal microbiota transplantation (FMT) has been hypothesised to have a positive effect in patients with IBS. We performed a randomised, double-blind placebo-controlled trial to investigate if FMT resulted in an altered gut microbiota and improvement in clinical outcome in patients with IBS.

DESIGN

We performed this study in 52 adult patients with moderate-to-severe IBS. At the screening visit, clinical history and symptoms were assessed and faecal samples were collected. Patients were randomised to FMT or placebo capsules for 12 days and followed for 6 months. Study visits were performed at baseline, 1, 3 and 6 months, where patients were asked to register their symptoms using the IBS-severity scoring system (IBS-SSS) and IBS-specific quality of life (IBS-QoL). Prior to each visit, faecal samples were collected.

RESULTS

A significant difference in improvement in IBS-SSS score was observed 3 months after treatment (p=0.012) favouring placebo. This was similar for IBS-QoL data after 3 months (p=0.003) favouring placebo. Patients receiving FMT capsules had an increase in faecal microbial biodiversity while placebos did not.

CONCLUSION

In this randomised double-blinded placebo-controlled study, we found that FMT changed gut microbiota in patients with IBS. But patients in the placebo group experienced greater symptom relief compared with the FMT group after 3 months. Altering the gut microbiota is not enough to obtain clinical improvement in IBS. However, different study designs and larger studies are required to examine the role of FMT in IBS.

TRIAL REGISTRATION NUMBER

NCT02788071.

Case series of successful treatment with fecal microbiota transplant (FMT) oral capsules mixed from multiple donors even in patients previously treated with FMT enemas for recurrent Clostridium difficile infection

RATIONALE

Studies have shown that fecal microbiota transplantation (FMT) is a safe and highly efficient treatment for recurrent Clostridium difficile infection (rCDI). However, it is still unknown if one versus multiple donors or enemas versus capsule FMT are most efficient.

PATIENT CONCERNS

10 patients with at least 3 previous episodes of CDI were offered treatment with FMT capsules. 9 patients decided to participate.

DIAGNOSES

In this study, we treated 9 patients (25-86 years) with rCDI.

INTERVENTIONS

From October to November 2016, a total of 9 patients with recurrent CDI were treated with oral fecal microbiota capsules, with mixed donor feces from 4 donors with high microbiota diversity. All patients received treatment with vancomycin prior to the capsule regime.

OUTCOME

Patients had previous recurrences ranging from 2 to 10 recurrences. All 9 patients were successfully treated without recurrence after 180 days follow-up, even 2 patients previously treated with FMT enemas.

LESSONS

FMT capsules based on multiple donors are highly efficient in patients with rCDI.

[Gut microbiota and depressive symptoms]

The gut microbiota is believed to affect a wide variety of mental disorders, including depression. The hypothesis involves bacterial signalling to the host through metabolic, endocrinal, immunologic and neuronal pathways. Few studies of patients with depression have shown altered microbiota profiles and increased levels of systemic endotoxin, which can be detected by leucocytes and result in expression of cytokines. Studies performed so far have lacked statistical power and provide no causal explanation for the gut-brain hypothesis. Further research into the matter is certainly warranted.

Can fecal microbiota transplantation cure irritable bowel syndrome?

AIM

To verify the utility of treatment with fecal microbiota transplantation (FMT) in patients with irritable bowel syndrome (IBS).

METHODS

We searched EMBASE, Cochrane Library and PubMed in March, 2017. The reviewed literature was based on two systematic searches in each of the databases. The MeSH terms used were IBS and fecal microbiota transplantation and the abbreviations IBS and FMT. Reference lists from the articles were reviewed to identify additional pertinent articles.

RESULTS

A total of six conference abstracts, one case report, one letter to the editor, and one clinical review were included. In the final analysis, treatment of 48 patients was evaluated. Treatment revealed an improvement in 58% of cases. The varying structure of the nine included studies must be taken into consideration.

CONCLUSION

Data on FMT and IBS are too limited to draw sufficient conclusions. Standardized double blinded randomized clinical trials need to be carried out to evaluate the effect of FMT on IBS.

Ubiquitin promoter-based vectors for high-level expression of selectable and/or screenable marker genes in monocotyledonous plants

A set of plasmids has been constructed utilizing the promoter, 5' untranslated exon, and first intron of the maize ubiquitin (Ubi-1) gene to drive expression of protein coding sequences of choice. Plasmids containing chimaeric genes for ubiquitin-luciferase (Ubi-Luc), ubiquitin-beta-glucuronidase (Ubi-GUS), and ubiquitin-phosphinothricin acetyl transferase (Ubi-bar) have been generated, as well as a construct containing chimaeric genes for both Ubi-GUS and Ubi-bar in a single plasmid. Another construct was generated to allow cloning of protein coding sequences of choice on Bam HI and Bam HI-compatible restriction fragments downstream of the Ubi-1 gene fragment. Because the Ubi-1 promoter has been shown to be highly active in monocots, these constructs may be useful for generating high-level gene expression of selectable markers to facilitate efficient transformation of monocots, to drive expression of reference reporter genes in studies of gene expression, and to provide expression of biotechnologically important protein products in transgenic plants.

The Helicobacter pylori theory and duodenal ulcer disease. A case study of the research process

OBJECTIVES

To describe the medical research process from the time of the generation of a new theory to its implementation in clinical practice. The Helicobacter pylori (H. pylori) theory, i.e. the theory that H. pylori plays a significant causal role in duodenal ulcer disease was chosen as a case.

MATERIAL

Abstracts from 1984 to 1993, identified in the CD-Rom, Medline system, ("Silverplatter"), using the search terms Campylobacter pylori and Helicobacter pylori, and reviews and editorials about H. pylori in some of the most widespread clinical journals.

RESULTS

2204 papers on H. pylori were published, of which 64% (1,403) were original articles. Of these, 30% (415/1,403) were descriptive clinical studies, 5% (64) were epidemiological studies, 33% (459) were laboratory studies of disease mechanisms, 8% (112) were therapeutic intervention studies, and 24% (336) concerned diagnostic and therapeutic techniques. A total of 204 of the clinical studies addressed duodenal ulcer disease. Of these, 72% (147) were cross-sectional studies, 3% (7) were observational cohort studies and 25% (50) were therapeutic intervention studies. Thirty-one editorials and reviews concerning the etiological role of H. pylori in duodenal ulcer disease had been published in some of the most widespread clinical journals. In half of the papers the authors were convinced of the causal role of H. pylori in duodenal ulcer disease, while in the remainder they were sceptical. In seven cases the authors stated which patients should be selected for H. pylori eradication treatment.

CONCLUSION

Descriptive clinical studies and laboratory studies of disease mechanisms were the prevailing types of research about H. pylori. Comparatively few therapeutic intervention studies were done; this fact may have hampered the acceptance of the H. pylori theory and the introduction of eradication therapy in clinical practice.

Non-systemic expression of a stress-responsive maize polyubiquitin gene (Ubi-1) in transgenic rice plants

We have used the promoter, 1st exon and 1st intron of the maize polyubiquitin gene (Ubi-1) for rice transformation experiments and revealed the characteristic expression of Ubi-1 gene: (1) Ubi-1 gene is not regulated systemically but rather individual cells respond independently to the heat or physical stress; (2) Ubi-1 gene changes its tissue-specific expression in response to stress treatment; (3) the expression of Ubi-1 gene is dependent on cell cycle.

Do clinicians accept the role of Helicobacter pylori in duodenal ulcer disease: a survey of European gastroenterologists and general practitioners

OBJECTIVES

To examine to what extent clinicians in Europe accepted the theory of the casual role of Helicobacter pylori (H.pylori) in duodenal ulcer disease in the year 1992, and to what extent the theory had influenced their diagnostic and therapeutic habits in the management of duodenal ulcer patients at that time.

DESIGN

Postal questionnaire.

SETTING

Three European countries: the UK, the Netherlands, and Denmark.

SUBJECTS

Three hundred and three gastroenterologists, 250 general practitioners, 83 junior hospital doctors.

MAIN OUTCOME MEASURES

Number of doctors believing H. pylori to be a significant cause of duodenal ulcer disease, use of diagnostic tests for detection of H. pylori and therapeutic regimens for eradicating H. pylori.

RESULTS

Four hundred and forty-two doctors replied. Eighty-four per cent of the British doctors, 73% of the Dutch doctors, and 47% of the Danish doctors accepted the role of H. pylori in duodenal ulcer disease. The rates were higher among gastroenterologists than among general practitioners. Eighty-four per cent of the British doctors, 80% of the Dutch doctors, and 48% of the Danish doctors used diagnostic tests for H. pylori, most frequently histological examination (64%). In patients with duodenal ulcer disease, H. pylori eradication was undertaken by 93% of the British doctors, 89% of the Dutch doctors, and 60% of the Danish doctors. A triple therapy (a bismuth salt, metronidazole, and either amoxicillin or tetracycline) was used by 57% (181/315) of the doctors.

CONCLUSIONS

H.pylori treatment is frequently used in some countries. However, the role of H. pylori in duodenal ulcer disease has not been accepted to the same extent in different European countries.

Opinions in Denmark on the causes of peptic ulcer disease. A survey among Danish physicians and patients

The aim of the study was to investigate opinions among Danish patients and physicians on causes of peptic ulcer disease. Fifty-nine patients with an ulcer history and 77 physicians with a special interest in gastroenterology participated. They were given a questionnaire listing 16 possible causes of peptic ulcer and indicated for each whether they believed it was a contributory cause of the disease. The patients stated 0-10 causes each (median, 4), and the physicians 3-12 causes (median, 6) (p < 0.01). Younger physicians stated more causes than did the older ones (p < 0.01), and female physicians stated more causes than did their male colleagues (p < 0.01). Seventy-five per cent of the patients indicated that psychologic factors, such as grief, anxiety, and stress, were contributory causes of peptic ulcer disease, whereas only around 40% believed that coffee/tea, alcohol, smoking, side effects of medicine, and working conditions played a causal role. Around 95% of the physicians indicated that medical drugs and smoking were contributory causes of peptic ulcer disease, and around 80% that alcohol and psychologic factors were so. Only 30-40% of the physicians believed that coffee/tea, food habits, infection, and working conditions could play a causal role in ulcer disease. It is concluded that the opinion on causal agents in peptic ulcer disease differ considerably among both patients and physicians. Opinions on causes of diseases may influence the way we treat and advise our patients, and attempts should thus be made to unify our knowledge and interpretations of causes of diseases to reach more solid ground in counselling our patients.

Expression of a Maize Ubiquitin Gene Promoter-bar Chimeric Gene in Transgenic Rice Plants

We have constructed a chimeric gene consisting of the promoter, first exon, and first intron of a maize ubiquitin gene (Ubi-1) and the coding sequence of the bar gene from Streptomyces hygroscopicus. This construct was transferred into rice (Oryza sativa L.) protoplasts via electroporation, and 10 plants were regenerated from calli that had been selected for resistance to exogenously supplied bialaphos. Transgenic plants grown in a greenhouse were resistant to both bialaphos and phosphinothricine at a dosage lethal to untransformed control plants. Evidence of stable integration of the transferred gene into the genome of the regenerated primary transformant plants was obtained from Southern blot analysis. In addition, northern blot analysis indicated expression and proper splicing of the maize ubiquitin gene first intron from the primary chimeric transcript in these transgenic rice plants, and western blot analysis and enzymic assays verified expression of the active bar gene product. Apparent mendelian segregation for bialaphos resistance in T(1) progeny of primary transformants was confirmed.

Observer homogeneity in the histologic diagnosis of Helicobacter pylori. Latent class analysis, kappa coefficient, and repeat frequency

Four pathologists independently examined 82 antral mucosal biopsy specimens for the presence of Helicobacter pylori and indicated whether their assessments were certain. The pathologists made a positive diagnosis in from 56% to 84% of the specimens (significant heterogeneity, p < 0.01). The frequency of uncertain diagnoses was from 4% to 20% (p < 0.01). Uncertain statements occurred more frequently among negative than among positive diagnoses. For the six pairs of observers the kappa coefficients were between 0.39 and 0.82. By a latent class analysis measures of diagnostic accuracy were calculated comparing the observers' assessments with an estimated consensus diagnosis. The predictive values of a positive diagnosis ranged from 0.70 to 1.00. By calculation of repeat frequencies--that is, the probability that an observer's statement was confirmed by another observer--it became evident that uncertain statements were less frequently (61%) confirmed than were certain ones (85%). It is concluded that observer homogeneity is only moderate with regard to the histologic diagnosis of H. pylori, which should be considered both in daily clinical routine and in scientific studies. Disagreement between observers was associated with negative diagnoses, presumably because the pathologists felt more uncertain in these cases.

Maize polyubiquitin genes: structure, thermal perturbation of expression and transcript splicing, and promoter activity following transfer to protoplasts by electroporation

Two genomic clones (lambda Ubi-1 and lambda Ubi-2) encoding the highly conserved 76 amino acid protein ubiquitin have been isolated from maize. Sequence analysis shows that both genes contain seven contiguous direct repeats of the protein coding region in a polyprotein conformation. The deduced amino acid sequence of all 14 repeats is identical and is the same as for other plant ubiquitins. The use of transcript-specific oligonucleotide probes shows that Ubi-1 and Ubi-2 are expressed constitutively at 25 degrees C but are inducible to higher levels at elevated temperatures in maize seedlings. Both genes contain an intron in the 5' untranslated region which is inefficiently processed following a brief, severe heat shock. The transcription start site of Ubi-1 has been determined and a transcriptional fusion of 0.9 kb of the 5' flanking region and the entire 5' untranslated sequence of Ubi-1 with the coding sequence of the gene encoding the reporter molecule chloramphenicol acetyl transferase (CAT) has been constructed (pUBI-CAT). CAT assays of extracts of protoplasts electroporated with this construct show that the ubiquitin gene fragment confers a high level of CAT expression in maize and other monocot protoplasts but not in protoplasts of the dicot tobacco. Expression from the Ubi-1 promoter of pUBI-CAT yields more than a 10-fold higher level of CAT activity in maize protoplasts than expression from the widely used cauliflower mosaic virus 35S promoter of a 35S-CAT construct. Conversely, in tobacco protoplasts CAT activity from transcription of pUBI-CAT is less than one tenth of the level from p35S-CAT.

[Duodenal ulcer in systemic mastocytosis]

Two cases of systemic mastocytosis are presented. Both patients had peptic ulceration. Greatly raised values on investigation of gastric acid secretion in patients with therapy-resistant peptic ulceration and normal serum gastrin should raise the suspicion of systemic mastocytosis.

phyB is evolutionarily conserved and constitutively expressed in rice seedling shoots

Southern blot analysis indicates that the rice genome contains single copies of genes encoding type A (phyA) and type B (phyB) phytochromes. We have isolated overlapping cDNA and genomic clones encoding the entire phyB polypeptide. This monocot sequence is more closely related to phyB from the dicot, Arabidopsis (73% amino acid sequence identity), than it is to the phyA gene in the rice genome (50% identity). These data support the proposal that phyA and phyB subfamilies diverged early in plant evolution and that subsequent divergence accompanied the evolution of monocots and dicots. Moreover, since rice and Arabidopsis phyB polypeptides are more closely related to one another (73% identity) than are monocot and dicot phyA sequences (63-65% identity), it appears that phyB has evolved more slowly than phyA. Sequence conservation between phyA and phyB is greatest in a central core region surrounding the chromophore attachment site, and least toward the amino-terminal and carboxy-terminal ends of the polypeptides, although hydropathy analysis suggests that the overall structure of the two phytochromes has been conserved. Gene-specific Northern blot analysis indicates that, whereas phyA is negatively regulated by phytochrome in rice seedling shoots in the manner typical of monocots, phyB is constitutively expressed irrespective of light treatment. In consequence, phyA and phyB transcripts are equally abundant in fully green tissue. Since Arabidopsis phyB mRNA levels are also unaffected by light, the present results suggest that this mode of regulation is evolutionarily conserved among phyB genes, perhaps reflecting differences in the functional roles of the different phytochrome subfamilies.

[False negative mammography]

During the period 1.1.1984-31.12.1986, primary surgical treatment of 423 women with palpaple, invasively progressing cancer of the breast was performed. All of these had been examined mammographically prior to operation. The uncorrected nosographical sensitivity of the mammographic investigation was 0.93, decreasing to 0.83 prior to the age of 50 years. It is emphasized that patients in whom there is a disproportion between the mammographic and palpatory findings must be referred for surgical assessment without delay.

Structure and expression of a maize phytochrome-encoding gene

We have isolated genomic clones for three loci encoding the phytochrome polypeptide of Zea mays, and have determined the entire sequence of one of them (phyA1) together with approximately 1 kb of 5' flanking DNA. The structure of this gene is highly conserved in comparison with other phytochrome-encoding genes (phy). The deduced amino acid (aa) sequence indicates that the maize phytochrome protein is 1130 aa long (125 kDa). Overall aa sequence identity is 88% with Avena and rice type A phytochromes and 65% with the type A phytochromes of the dicots, pea, zucchini and Arabidopsis. Northern analysis indicates that maize phy transcripts are down-regulated only two- to threefold in etiolated seedlings 3 h after a red light pulse, in contrast to Avena where a ten- to 20-fold decrease is observed. On the other hand, a more than tenfold reduction in maize phy mRNA abundance occurs in seedlings transferred to white light for 24 h. Several conserved sequence elements have been identified by comparison of the maize phyA1 and other monocot phy promoters, suggesting that these common regions may be regulatory elements involved in phy expression.

Photoregulation of a phytochrome gene promoter from oat transferred into rice by particle bombardment

The regulatory photoreceptor phytochrome controls the transcription of its own phy genes in a negative feedback fashion. We have exploited microprojectile-mediated gene transfer to develop a rapid transient expression assay system for the study of DNA sequences involved in the phytochrome-regulated expression of these genes. The 5'-flanking sequence and part of the structural region of an oat phy gene have been fused to a reporter coding sequence (chloramphenicol acetyltransferase, CAT) and introduced into intact darkgrown seedlings by using high-velocity microprojectiles. Expression is assayable in less than 24 hr from bombardment. The introduced oat phy-CAT fusion gene is expressed and down-regulated by white light in barley, rice, and oat, whereas no expression is detected in three dicots tested, tobacco, cucumber, and Arabidopsis thaliana. In bombarded rice shoots, red/far-red light-reversible repression of expression of the heterologous oat phy-CAT gene shows that it is regulated by phytochrome in a manner parallel to that of the endogenous rice phy genes. These data indicate that the transduction pathway components and promoter sequences involved in autoregulation of phy expression have been evolutionarily conserved between oat and rice. The experiments show the feasibility of using high-velocity microprojectile-mediated gene transfer for the rapid analysis of light-controlled monocot gene promoters in monocot tissues that until now have been recalcitrant to such studies.

Sequence analysis and transcriptional regulation by heat shock of polyubiquitin transcripts from maize

We have isolated a maize ubiquitin cDNA clone which encodes one partial and three full-length, identical 76 amino acid repeats, in a polyprotein conformation. The deduced amino acid sequence of the mature monomeric polypeptide is identical to that determined for three other plants, barley, oat, and Arabidopsis, and differs from yeast and animal ubiquitin by only two and three amino acids, respectively. Hybridization of the cDNA clone to restriction endonuclease-digested genomic DNA revealed that ubiquitin is encoded by a small multigene family in maize. Northern blot analysis of poly(A)(+) RNA indicated that multiple ubiquitin mRNAs of 2.1, 1.6 and 0.8 kb are produced in maize shoots and roots. The abundance of the largest (2.1 kb) of these transcripts increased transiently 3- to 4-fold over the first 1 to 3 h in seedlings that were subjected to heat shock, and then returned dramatically within 1 h almost to the preshocked level. In contrast, the two smaller transcripts showed little or no change following heat shock. Run-on transcription assays in isolated maize nuclei showed a heat shock-induced increase in ubiquitin run-on transcripts that paralleled the increase in mature 2.1 kb mRNA levels over the first 3 h following the heat shock treatment. This result indicates that heat shock regulates ubiquitin gene expression at least in part at the transcriptional level. The subsequent rapid decline in steady-state mRNA levels, on the other hand, was not preceded by decreased ubiquitin gene transcription, raising the possibility of both transcriptional and posttranscriptional regulation. The run-on transcription assays also revealed a transient 5-fold reduction in rRNA gene transcription following heat shock, indicating that the transcriptional machinery for these genes is selectively sensitive to this stress.

Isolation and characterization of a maize chlorophyll a/b binding protein gene that produces high levels of mRNA in the dark

A cDNA library prepared using mRNA isolated from red-light irradiated maize seedlings was screened by a difference procedure for clones that represent red-light regulated mRNA. Two such clones were found to represent mRNA for a chlorophyll a/b binding protein (CAB), and one of these (pAB1084) was used to screen a maize genomic library. One positive genomic clone (lambda AB1084) was isolated and sequenced. The gene represented by lambda AB1084, which we designate maize cab-1, contains extensive nucleotide homology within its protein coding region to CAB genes from other species. The boundaries of the transcribed region of the cab-1 gene were determined by S1 nuclease mapping. The 5' terminus of cab-1 mRNA is located 52-54 nucleotides (nt) upstream of the translation start site and 34 nt downstream of a TATA box. As in the case of petunia CAB genes, several poly(A) addition sites are present in mRNA from the cab-1 gene. The 5' flanking DNA of cab-1 contains sequences related to elements that have been implicated in the light-regulated expression of CAB and rbcS genes in other plant systems. Quantitative Northern blot hybridization analysis using a gene specific probe for cab-1 indicates that the mRNA for this gene is present at 0.4% of the total mRNA and up to 80% of the total CAB mRNA in the leaves of dark-grown seedlings. In consequence, although the degree of up-regulation by white light is only moderate (3- to 6-fold), cab-1 transcripts account for approximately 2% of the mRNA in the leaves of light-grown seedlings.

Phytochrome and the regulation of the expression of its genes

In attempting to understand the mechanism of phytochrome action we are studying structural properties of the photoreceptor molecule and the autoregulation of expression of phytochrome genes. Run-off transcription assays in isolated nuclei from Avena indicate that phytochrome decreases the transcription of its own genes threefold in less than 15 min form Pfr formation. The extent of this decrease is insufficient to account for the observed 10- to 50-fold decrease in mature phytochrome mRNA levels, suggesting that enhanced degradation may also play a significant role in determining the level of this mRNA. Structural analysis of native phytochrome from Avena indicates that the molecule is an elongated dimer of 124 kDa monomers, each consisting of a globular, 74 kDa, NH2-terminal domain bearing the single chromophore at Cys-321, and a more open COOH-terminal domain that bears the dimerization site. Controlled proteolysis and binding of monoclonal antibodies to mapped epitopes has identified two regions, one in the 6-10 kDa NH2-terminal segment and the other ca. 70 kDa from the NH2-terminus, that undergo photoconversion-induced conformational changes and are therefore candidates for involvement in the molecule's regulatory function. Comparison of the full-length amino acid sequences of Avena and Cucurbita phytochromes, derived from nucleotide sequence analysis, indicates overall homology of 65%. The most highly conserved regions are those immediately surrounding the chromophore attachment site, where 29 residues are invariant, and a hydrophobic region between residues 150 and 300, postulated to form a cavity containing the chromophore. In contrast, a strikingly lower level of homology exists at the COOH-terminus of the polypeptide between residues 800 and 1128, indicating a possible lack of involvement of this region in phytochrome function.

Identification of a Rhizobium trifolii plasmid coding for nitrogen fixation and nodulation genes and its interaction with pJB5JI, a Rhizobium leguminosarum plasmid

Rhizobium trifolii T37 contains at least three plasmids with sizes of greater than 250 megadaltons. Southern blots of agarose gels of these plasmids probed with Rhizobium meliloti nif DNA indicated that the smallest plasmid, pRtT37a, contains the nif genes. Transfer of the Rhizobium leguminosarum plasmid pJB5JI, which codes for pea nodulation and the nif genes and is genetically marked with Tn5, into R. trifolii T37 generated transconjugants containing a variety of plasmid profiles. The plasmid profiles and symbiotic properties of all of the transconjugants were stably maintained even after reisolation from nodules. The transconjugant strains were placed into three groups based on their plasmid profiles and symbiotic properties. The first group harbored a plasmid similar in size to pJB5JI (130 megadaltons) and lacked a plasmid corresponding to pRtT37a. These strains formed effective nodules on peas but were unable to nodulate clover and lacked the R. trifolii nif genes. This suggests that genes essential for clover nodulation as well as the R. trifolii nif genes are located on pRtT37a and have been deleted. The second group harbored hybrid plasmids formed from pRtT37a and pJB5JI which ranged in size from 140 to ca. 250 megadaltons. These transconjugants had lost the R. leguminosarum nif genes but retained the R. trifolii nif genes. Strains in this group nodulated both peas and clover but formed effective nodules only on clover. The third group of transconjugants contained a hybrid plasmid similar in size to pRtT37b. These strains contained the R. trifolii and R. leguminosarum nif genes and formed N2-fixing nodules on both peas and clover.

Autogenous skull cranioplasty: fresh and preserved (frozen), with consideration of the cellular response

Every craniotomy requires immediate replacement of a fresh autograft of skull or, in the presence of cerebral swelling, delayed reimplantation of preserved autogenous skull. Resumption of osteogenesis, the index of viability, determines the effectiveness of these segments of calvaria in protecting the brain and restoring skull conformity. The cellular response in skull replaced either at the end of craniotomy or after frozen preservation was studied by light and fluorescence microscopy, skull roentgenograms, and radionuclide scintigraphy. In 5 patients eventual total remodeling of skull was found at the time of a second craniotomy performed from 1 to 19 years after the first. In 12 patients skull sections removed aseptically at craniotomy were frozen and stored for 1 to 35 months at -20 degrees C in bacitracin. This cytotoxic preservative method fixed the tissue, which appeared unchanged on light microscopy and was sterile on bacteriological and fungal cultures. In 53 patients who underwent autogenous cranioplasty with skull stored frozen for 3 weeks to 19 months, 48 operations were totally successful. Complications included infections in 2 patients, resorption in 2 infants, and incomplete restoration in 1 adult. In 10 patients the sequential dynamics of skull revitalization were found to be: revascularization, resorption, and accretion. The repair of membranous skull is similar to that of endochondral bone of the skeleton. Skull is metabolically intensely active after reimplantation and is the ideal material for cranioplasty.