Osteogenic Differentiation Potential of Mesenchymal Stem Cells Using Single Cell Multiomic Analysis

Mesenchymal stem cells (MSC) are multipotent stem cells that can differentiate into multiple cell types, including osteoblasts, chondrocytes, and adipocytes. Osteoblast differentiation is reduced during osteoporosis development, resulting in reduced bone formation. Further, MSC isolated from different donors possess distinct osteogenic capacity. In this study, we used single-cell multiomic analysis to profile the transcriptome and epigenome of MSC from four healthy donors. Data were obtained from ~1300 to 1600 cells for each donor. These cells were clustered into four groups, indicating that MSC from different donors have distinct chromatin accessible regulatory elements for regulating gene expression. To investigate the mechanism by which MSC undergo osteogenic differentiation, we used the chromatin accessibility data from the single-cell multiome data to identify individual-specific enhancer-promoter pairs and evaluated the expression levels and activities of the transcriptional regulators. The MSC from four donors showed distinct differentiation potential into osteoblasts. MSC of donor 1 showed the largest average motif activities, indicating that MSC from donor 1 was most likely to differentiate into osteoblasts. The results of our validation experiments were consistent with the bioinformatics prediction. We also tested the enrichment of genome-wide association study (GWAS) signals of several musculoskeletal disease traits in the patient-specific chromatin accessible regions identified in the single-cell multiome data, including osteoporosis, osteopenia, and osteoarthritis. We found that osteoarthritis-associated variants were only enriched in the regions identified from donor 4. In contrast, osteoporosis and osteopenia variants were enriched in regions from donor 1 and least enriched in donor 4. Since osteoporosis and osteopenia are related to the density of bone cells, the enrichment of variants from these traits should be correlated with the osteogenic potential of MSC. In summary, this study provides large-scale data to link regulatory elements with their target genes to study the regulatory relationships during the differentiation of mesenchymal stem cells and provide a deeper insight into the gene regulatory mechanism.

POS0378 EVALUATION OF THE USE OF VIDEO CONSULTATION IN GERMAN RHEUMATOLOGY CARE BEFORE AND DURING THE COVID-19 PANDEMIC WAVES

Background

During the COVID-19 pandemic telemedicine tools rapidly and widely gained acceptance as indispensable management tools for the continuum of clinical care in rheumatic diseases. They have been adopted in position papers and guidelines for the management of rheumatic diseases in adult patients.

Objectives

Evaluation of the use of video consultation as one form of telemedicine before and during the COVID-19 pandemic and associated lockdowns among Rheumatology physicians in Germany. The survey results are expected to support the optimization and implementation of video consultation (VC) into routine clinical practice in rheumatology, providing long-term benefits for both parties, patients and their treating rheumatologists.

Methods

Cross-sectional nationwide online survey among German rheumatologists and rheumatologists in training. The survey was promoted by newsletters sent by means of mail and Twitter posts to members of the German Society for Rheumatology (n=1,650) and German Professional Society for Rheumatology (n=527).

Results

Reported data refer to 205 participants. The majority of respondents was male (59%), older than 40 years (90%) and specialized in internal medicine/rheumatology (85%).

They were divided into two groups: ‘digital users’ (38%) and ‘digital non-users’ (62%). Users employing telemedicine (TM) but never VC were defined as ‘TM-users’ (10%). Those using TM and VC were classified as ‘VC-users’ (27%). ‘Non-users’ negated the use of VC and TM respectively.

Knowledge on telemedicine was self-rated as 4 (median on a Likert Scale 1 (very high) to 6 (very low)) with a significant difference between user (VC-user 2.7±1.2, TM-user 3.2±1.1) and non-user (4.4±1.3).

The Figure 1 shows a significant increase in the use of VC during the lockdown periods. Even between the lockdown phases, VC use was higher than in the pre-pandemic phase.

Figure 1.

Grouped patient numbers seen via VC during the pandemic waves

Reasons for VC non-use in TM-user and non-user were administrative/technical efforts (21%), lack of technical equipment (15%), time constraints (12%), time required for individual VC sessions (12%), inadequate reimbursement (11%), lack of demand from patients (11%), data security concerns (9%), poor internet connection (8%), and lack of scientific evaluation/evidence (5%).

Based on the experience gained, physicians considered the following clinical situations to be particularly suitable for VC: follow-up visits (VC-user 79%, TM-user 62%, non-user 47%), emergency consultations (VC-user 20%, TM-user 33%, non-user 20%), and patients presenting for the first time (VC-user 11%, TM-user 19%, non-user 8%).

Table 1.

Evaluation of the VC in comparison to other patient interaction (VC-user) on a Likert Scale with 1 (I agree completely) to 6 (I do not agree at all)

VC isMean ± standard deviation (median)… comparable to a face to face meeting (n=52)4.3 ± 1.3 (4.5)… comparable to a telephone consultation (n=51)3.3 ± 1.3 (3.0)… suitable as an additional means of communication with the patient (n=51)2.3 ± 1.5 (2.0)

Conclusion

Despite the fact that the current pandemic situation, with social distancing and several lockdowns, provides an ideal environment for the implementation of new remote care forms such as VC, their use and acceptance remained below expectations. Given the reported decline in physician face-to-face consultations during the pandemic, these findings are even more concerning. The identified reasons for non-utilization should be addressed by policy makers, payers and medical societies to provide better foundations for future innovative care models.

Disclosure of Interests

Joana Reiter: None declared, Gamal Chehab: None declared, Peer Aries: None declared, Felix Muehlensiepen Speakers bureau: Novartis Pharma GmbH, Grant/research support from: Novartis Pharma GmbH & AbbVie Deutschland GmbH & Co. KG, Martin Welcker: None declared, Anna Voormann: None declared, Matthias Schneider Speakers bureau: Astra-Zeneca; Biogen; BMS; Celgene; Chugai; GSK; Janssen-Cilag; Lilly; Pfizer; UCB, Paid instructor for: Lilly, Consultant of: Abbvie; Astra-Zeneca; Boehringer-Ingelheim; GSK; Lilly; Novartis; Pfizer; Protagen; Roche; Sanofi-Aventis; UCB, Grant/research support from: Abbvie; Astra-Zeneca; GSK; UCB, Christof Specker: None declared, Jutta G. Richter: None declared

The Long-Term Effect of a Quality Improvement Intervention in the Management of Bronchiolitis

Quality improvement interventions have been shown to improve adherence with bronchiolitis treatment guidelines; however, the long-term effect of these interventions is unclear. We show that while such an intervention led to a long-lasting change, this was attenuated with time. Repeated interventions are required to maintain guideline adherence.

An advanced lithium-air battery exploiting an ionic liquid-based electrolyte

A novel lithium-oxygen battery exploiting PYR14TFSI-LiTFSI as ionic liquid-based electrolyte medium is reported. The Li/PYR14TFSI-LiTFSI/O2 battery was fully characterized by electrochemical impedance spectroscopy, capacity-limited cycling, field emission scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The results of this extensive study demonstrate that this new Li/O2 cell is characterized by a stable electrode-electrolyte interface and a highly reversible charge-discharge cycling behavior. Most remarkably, the charge process (oxygen oxidation reaction) is characterized by a very low overvoltage, enhancing the energy efficiency to 82%, thus, addressing one of the most critical issues preventing the practical application of lithium-oxygen batteries.

Macrolides for the long-term management of asthma--a meta-analysis of randomized clinical trials

BACKGROUND

Macrolide antibiotics, which have anti-inflammatory and immune modulatory effects, have been studied as adjuncts for the management of asthma. However, results have been contradictory and trials underpowered. We therefore sought to conduct a meta-analysis of randomized controlled trials (RCT).

METHODS

All RCT of prolonged macrolides (3+ weeks) for asthma treatment, published up to January 2013 in MEDLINE, Scopus, CINAHL, Highwire, and The Cochrane Collaboration Library, were included. Fixed- or random-effects models were used to calculate pooled weighted or standard mean differences (WMD or SMD, respectively).

RESULTS

A total of 12 studies were included for analysis. The pooled effect of macrolides on FEV1 (eight trials, 381 subjects) was not significant (SMD 0.05, 95% CI -0.14-0.25), but there was a significant increase in peak expiratory flow (four trials, 419 subjects; WMD 6.7, 95% CI 1.35-12.06). Pooled analysis also showed significant improvements in symptom scores (eight studies, 478 subjects; WMD -0.46, 95% CI -0.60 to -0.32), quality of life (five trials, 346 subjects; WMD 0.18, 95% CI 0.001-0.37), and airway hyper-reactivity (two trials, 131 subjects; SMD 1.99, 95% CI 0.46-3.52). Post hoc evaluation showed limited statistical power to detect significant differences in FEV1.

CONCLUSIONS

Macrolide administration for asthma for three or more weeks was not associated with improvement in FEV1, but produced significant improvements in peak expiratory flow, symptoms, quality of life, and airway hyper-reactivity. Macrolides may therefore be beneficial as adjunct asthma therapy. Future trials, focusing on long-term safety and effectiveness, should use standardized outcomes and procedures.

Type 1 diabetes and prolonged fasting

AIMS

Fasting is common in several religions. The aims of this study were to determine if prolonged fasting (> 25 h) is safe for individuals with Type 1 diabetes and to identify factors associated with success.

METHODS

Patients intending to fast were instructed on insulin dose adjustments, frequent glucose monitoring and when to terminate the fast using a standard protocol. Clinical and epidemiological factors were recorded and a comparison was made between successful and unsuccessful fasters.

RESULTS

Of 56 subjects who intended to fast, 37 (65%) were successful. Individuals terminated their fast in the presence of either hypoglycaemia or hyperglycaemia and adherence to the protocol was high. There were no serious side-effects of fasting. Successful fasters had greater reductions in insulin dosage and higher HbA(1c). There were no differences between individuals taking intermittent insulin injections and those with continuous infusion pumps.

CONCLUSIONS

Persons with Type 1 diabetes can participate safely in prolonged fasts provided they reduce their usual insulin dose significantly and adhere to guidelines regarding glucose monitoring and indications for terminating fasting.

Type 1 diabetes risk assessment: improvement by follow-up measurements in young islet autoantibody-positive relatives

AIMS/HYPOTHESIS

Combinations of autoantibody characteristics, including antibody number, titre, subclass and epitope have been shown to stratify type 1 diabetes risk in islet autoantibody-positive relatives. The aim of this study was to determine whether autoantibody characteristics change over time, the nature of such changes, and their implications for the development of diabetes.

METHODS

Five-hundred and thirteen follow-up samples from 141 islet autoantibody-positive first-degree relatives were tested for islet autoantibody titre, IgG subclass, and GAD and IA-2 antibody epitope. All samples were categorised according to four risk stratification models. Relatives had a median follow-up of 6.8 years and 48 developed diabetes during follow-up. Survival analysis was used to determine the probability of change in risk category and of progression to diabetes.

RESULTS

For each stratification model, the majority of relatives (71-81%) remained in the same risk category throughout follow-up. In the remainder, changes occurred both from lower to higher and from higher to lower risk categories. For all four models, relatives aged < 15 years were more likely to change risk category than those aged >15 years (0.001 < p < 0.03). Relatives whose autoantibody status changed from low- to high-risk categories had a higher risk of diabetes than relatives who remained in low-risk categories, and inclusion of autoantibody status during follow-up improved diabetes risk stratification in Cox proportional hazards models (p < 0.001).

CONCLUSIONS/INTERPRETATION

Changes in islet autoantibodies are relevant to pathogenesis, and are likely to signal alterations in the disease process. Detection of changes through follow-up measurement will improve diabetes risk stratification, particularly in young individuals.

[Human cloning. The biological fundamentals and an ethical-legal assessment]

Following a description of the cloning process and how this might be used in humans, the authors examine the possibility of human cloning in the light of recognised ethical principles. They also address the question of whether current national and international laws are sufficient to prevent such practices.

Development of the body dysmorphic disorder examination

The Body Dysmorphic Disorder Examination (BDDE) is a semi-structured clinical interview designed to diagnose body dysmorphic disorder and to measure symptoms of severely negative body image. It tape into preoccupation with and negative evaluation of appearance, self-consciousness and embarrassment, excessive importance given to appearance in self-evaluation, avoidance of activities, body camouflaging, and body checking. The BDDE had adequate internal consistency and test-retest and interrater reliability. It correlated with measures of body image, negative self-esteem, and psychological symptoms, and was sensitive to change following treatment of body dysmorphic disorder. The BDDE distinguished body dysmorphic disorder patients from clinical and non-clinical control subjects and agreed with other clinicians' diagnosis of body dysmorphic disorder. The BDDE provided unique information in predicting clinical status when controlling for psychological adjustment and other measures of body image.

[The optimization of group size for fattening rabbits in group housing on grids made of artificial material]

ZIKA-fattening rabbits in groups of 4, 8, 16, 32 and 64 animals (5 rabbits/m2) have been proved in 6 repetitions with all together 144 animals during the fattening period of nine weeks in regard to their fattening performance, health and behaviour. The aim was to find an optimal group size for fattening rabbits with respect to animal welfare. The results show, that fattening performance and health of the rabbits have not been influenced remarkably by group size, whereas behaviour was different in so far, as the rabbits in groups of 16 showed a greater percentage of relaxed positions as well as a remarkable smaller percentage of aggressive behaviour. Therefore the group with 16 fattening rabbits is that, which can be advised for the fattening of rabbits in the Hohenheimer group housing.

The Current State of Solar Modeling

Data from the Global Oscillation Network Group (GONG) project and other helioseismic experiments provide a test for models of stellar interiors and for the thermodynamic and radiative properties, on which the models depend, of matter under the extreme conditions found in the sun. Current models are in agreement with the helioseismic inferences, which suggests, for example, that the disagreement between the predicted and observed fluxes of neutrinos from the sun is not caused by errors in the models. However, the GONG data reveal subtle errors in the models, such as an excess in sound speed just beneath the convection zone. These discrepancies indicate effects that have so far not been correctly accounted for; for example, it is plausible that the sound-speed differences reflect weak mixing in stellar interiors, of potential importance to the overall evolution of stars and ultimately to estimates of the age of the galaxy based on stellar evolution calculations.

Cognitive-behavioral body image therapy for body dysmorphic disorder

Body dysmorphic disorder (BDD) is a distressing body image disorder that involves excessive preoccupation with physical appearance in a normal appearing person. Prior case reports of behavior therapy were encouraging, but no controlled evaluation of behavior therapy or any other type of treatment had been conducted. In the present study, 54 BDD subjects were randomly assigned to cognitive behavior therapy or no treatment. Patients were treated in small groups for eight 2-hour sessions. Therapy involved modification of intrusive thoughts of body dissatisfaction and overvalued beliefs about physical appearance, exposure to avoided body image situations, and elimination of body checking. Body dysmorphic disorder symptoms were significantly decreased in therapy subjects and the disorder was eliminated in 82% of cases at posttreatment and 77% at follow-up. Overall psychological symptoms and self-esteem also improved in therapy subjects.

Cognitive-behavioral body image therapy for body dysmorphic disorder

Body dysmorphic disorder (BDD) is a distressing body image disorder that involves excessive preoccupation with physical appearance in a normal appearing person. Prior case reports of behavior therapy were encouraging, but no controlled evaluation of behavior therapy or any other type of treatment had been conducted. In the present study, 54 BDD subjects were randomly assigned to cognitive behavior therapy or no treatment. Patients were treated in small groups for eight 2-hour sessions. Therapy involved modification of intrusive thoughts of body dissatisfaction and overvalued beliefs about physical appearance, exposure to avoided body image situations, and elimination of body checking. Body dysmorphic disorder symptoms were significantly decreased in therapy subjects and the disorder was eliminated in 82% of cases at posttreatment and 77% at follow-up. Overall psychological symptoms and self-esteem also improved in therapy subjects.

Assessment of body image in eating disorders with the body dysmorphic disorder examination

The Body Dysmorphic Disorder Examination (BDDE) has several advantages for the assessment of body image in eating disorder patients. It measures distressing self-consciousness, preoccupation with appearance, overvalued ideas about the importance of appearance to one's self-worth, and body image avoidance and checking behaviors. The BDDE is relevant for any type of appearance complaint and is not limited to weight or body shape concerns. The BDDE measures the useful targets for body image therapy. In a sample of eating disorder patients, the Body Dysmorphic Disorder Exam had good internal consistency and was significantly correlated with other measures of body image. It added new information to the discrimination of women with eating disorders from clinical and nonclinical controls beyond that provided by other measures of body image.

[Ethical aspects of gene manipulation]

It has become apparent that it is neither possible nor convenient to ignore all the possibilities of gene manipulation. Neither is it responsible to blindly trust in these techniques. The gains and risks must be weighed for every case. The recent amendment to the German guidelines for gene manipulation techniques does not mean that ethical discussions have ended, rather it is imperative that such discussions continue.

Extracellular signal regulated kinases. Localization of protein and mRNA in the human hippocampal formation in Alzheimer's disease

MAP kinases (MAPK) are a family of serine/threonine (Ser/Thr) kinases that link cell surface signals to changes in enzyme activity and gene expression. They are the products of the newly described gene family referred to as extracellular signal regulated kinases (ERKs). Moreover, MAPKs phosphorylate tau in vitro at Ser/Thr Proline sites, generating a multiply phosphorylated tau protein that is similar to the hyperphosphorylated tau found in Alzheimer neurofibrillary tangles (NFTs). We studied MAPK immunoreactivity and in situ hybridization patterns of the two major genes that comprise MAPK activity, ERK1 and ERK2, in the human hippocampal formation. Our goal was to determine whether the pattern of ERK expression is consistent with the hypothesis that MAPKs contribute to NFT formation. ERK1 mRNA is present in small amounts and confined primarily to dentate gyrus granule cells. ERK2 mRNA, by contrast, gives a much stronger hybridization signal and is present in dentate gyrus granule cells and pyramidal cells throughout all hippocampal subfields and adjacent temporal neocortex. Quantitative measures of ERK2 mRNA reveal that NFT-bearing neurons contain approximately 15% less ERK2 mRNA than nearest neighbors that do not contain NFT. NFT-bearing neurons contain approximately 25% less polyA mRNA, suggesting a relative preservation of ERK2 mRNA even in metabolically compromised cells. MAPK immunoreactivity (which represents both ERK1 and ERK2) is seen in neuronal soma, dendrites, axons, and in reactive astrocytes. In Alzheimer's disease, neurons that contain NFTs are also MAPK immunoreactive, but neurons that contain the highest amounts of MAPK immunoreactivity are not necessarily vulnerable for NFT. MAPK immunoreactivity is present in the same neurons as NFT and in the same subcellular compartments as tau, supporting a role for MAPKs in tau phosphorylation in Alzheimer's disease. However, the presence of ERK immunoreactivity is not sufficient to predispose neurons to NFT formation.

Extracellular signal-regulated kinase (MAP kinase) immunoreactivity in the rhesus monkey brain

Extracellular signal regulated kinases (ERKs) are a recently cloned family of genes that encode the MAP kinase protein kinases. They are highly expressed in brain and are believed to play an integral role in neural cellular responses to receptor activation. A role for ERKs has been postulated in Alzheimer's disease, where they have been implicated in phosphorylation of tau in neurofibrillary tangles. We explored the neuroanatomic distribution of ERK immunoreactivity in the rhesus monkey brain. The hippocampal formation, especially the mossy fiber zone and the molecular layer of the dentate gyrus are the most heavily immunostained areas. Cerebral cortex is, in general, more intensely stained in the supragranular layers. The caudate, putamen, and substantia nigra contain more immunoreactivity than the claustrum, globus pallidus, or thalamus with the exception of midline thalamic structures. These results suggest a marked regional and laminar distribution of ERKs in the primate brain.

[Human dignity and Christian ethics]

The jurisdiction of most states presumes that human dignity is unconditional. Yet a last reason for this dignity cannot be furnished by a state jurisdiction. Christian ethics for instance argue on a line beyond strictly rational interpretation: human dignity roots in man's affirmation by God. Beyond a simply negative definition it is essential today to define the conditions of human dignity in a positive way.

[Chances and risks of predictive medicine]

Ethical reasoning for predictive medicine is closely related to evaluating its chances and risks, for the individual (including future generations) and society. An optimistic viewpoint will emphasize the chances of predictive medicine. Yet it will be of great importance to differentiate overall political perspectives and the effects of any single operational step in regard to its life saving properties. Whenever predictive medicine leads to irresponsible risk it has to be disapproved of.

Cooperative ligand-lattice binding. Approximate Gaussian binding distribution

Nearest-neighbor cooperative binding of a ligand covering n sites and binding with equilibrium constant K and cooperativity factor omega to a large molecule with m binding sites (m much greater than n omega, n/omega) can be approximately described by a Gaussian distribution P(q-qmax), where q is the number of ligands bound and qmax the most probable value of q. The variance of the Gaussian is equal to the derivative dqmax/d ln(L), where L is the free ligand concentration. This variance, sigma 2, is a complicated function of qmax. However, in the limits of very large cooperativity, omega much greater than 1, very large anticooperativity, omega much less than 1, or noncooperativity, omega = 1, simpler expressions for sigma 2 can be given. For qmax = m/(n + 1), where the most probable number of bound ligands equals the number of free binding sites, sigma 2 has a particularly simple form: sigma 2 = 2m omega 1/2/(n + 1)3. The Gaussian and the infinite lattice approximations for the average number of ligands bound are good approximations only if sigma is much smaller than the number of binding sites. The variance may therefore provide an easy check on the validity of the infinite lattice approximation, which is commonly used to analyze experimental binding data.

Influence of vasoactive intestinal peptide, secretin, and Ala4, Val5-secretin on the net movements of electrolytes, fluid, and mucus in the rat colon in vivo

The effect of vasoactive intestinal peptide (VIP), secretin, and VIP-secretin (Ala4, Val5-secretin) on the net movements of sodium, potassium, fluid, and mucus was investigated in the rat colon perfused in vivo. Peptides (1-100 micrograms/kg.h) were infused intra-arterially. VIP influenced electrolyte and fluid movements at a threshold dose 10- to 100-fold lower than secretin, whereas the secretory efficacy was not significantly different. Replacing the NH2-terminal hexapeptide of secretin by that of VIP did not markedly alter the effect of secretin. Mucus output was stimulated weakly by all three peptides. The results indicate that the larger colonic secretory activity of VIP as compared to secretin is not primarily due to the difference in their NH2-terminal sequence but probably requires the intact molecule.

[Mechanism of action of combined administration of glibenclamide and insulin in type II diabetics with secondary failure of oral treatment]

In a double-blind placebo-controlled cross-over study eight type II diabetics (three men, five women), of whom six were at the point of late failure to oral treatment, were given an insulin infusion of 22 U human insulin/patient for 45 min (approximately 7 microU/kg X min); 30 min before infusion either glibenclamide (1 tablet Euglucon N) or placebo was administered. Glucose in venous blood, C-peptide, insulin, and glibenclamide concentrations in the blood plasma were simultaneously determined over a period of 210 min. The monitoring of glucose was handled using a Biostator. The insulin level reached a mean maximum of 400 to 500 microU/ml and was in a behavior of 100 microU/ml for 60 min. The areas under the concentration-time curves (AUCs) were practically identical in the two regimes. The blood glucose fell (in mean) from 260 mg/dl to 135 mg/dl and at the end of the experiment was in the range of 155 mg/dl. The glibenclamide concentrations reached maximal concentrations of 185 ng/ml 90 min after administration. The C-peptide concentrations fell in the placebo phase by more than 40%. In contrast, in the glibenclamide period there was at first a slight rise and later a slight marginal fall (initial, 2.0 ng/ml vs 1.9 ng/ml; 60 min, 1.3 ng/ml vs 1.8 ng/ml; 180 min, 1.2 ng/ml vs 1.8 ng/ml). Values after 90, 120, and 180 min were statistically different. The AUCs (0-180 min) were different (329 ng X min/ml vs 251 ng X min/ml). The inhibition of insulin secretion (measured by C-peptide) caused by exogenous insulin administration is largely abolished by glibenclamide.(ABSTRACT TRUNCATED AT 250 WORDS)

Vascular neoplasm of the esophagus with life-threatening hemorrhage. Report of a case

A rare case of life-threatening hemorrhage from a vascular neoplasm of the esophagus is presented. The exact nature of the lesion remained obscure in spite of careful histomorphologic analysis. After tumor extirpation no signs of recurrence were observed during a four-year follow-up period.

Antibody-mediated modulation of the immune response

We have studied the ability of monoclonal IgM and IgG antibodies to enhance or suppress immune responses and attempted to dissect the underlying mechanisms. Both IgM and IgG1 antibodies increased the rate of clearance of antigen from the circulation. Monoclonal IgM antibody to SRBC was found to specifically increase antibody responses, enhancement being insensitive to low doses of irradiation (150 R). IgM antibody specifically depressed the delayed hypersensitivity response to SRBC in vivo. Following administration of IgM in vivo, in vitro responses to SRBC were also enhanced. This in vitro enhancement appeared to depend on both T cells and B cells. In contrast, monoclonal IgG1 antibody to SRBC specifically depressed antibody responses in vivo. Such depressed antibody responses were also seen in vitro following IgG1 in vivo and did not appear to be due to the induction of suppressor T cells.

[Instrumental esophageal perforation--its treatment and results]

The number of oesophagus perforations has increased considerably with the increase in endoscopic, diagnostic and therapeutic procedures. 46 instrumental oesophagus perforations have been observed between 1973 and 1984. The youngest patient was a 2-year-old girl with a benign oesophagus stenosis and the eldest was an 89-year-old man with a neoplasm of the cardia. The average age was 62 years. 26 patients were treated conservatively; 20 patients were treated surgically. In 2 cases the oesophagus was diverted at the cervical level and the cardia detached. 8 months later this was successfully reconstructed. 9 out of 43 patients died. In every case, the cause of death were cardio-pulmonal complications accompanying general sepsis.

Concordance of experimentally mapped or predicted Z-DNA sites with positions of selected alternating purine-pyrimidine tracts

The recent electronmicroscopic and biochemical mapping of Z-DNA sites in phi X174, SV40, pBR322 and PM2 DNAs has been used to determine two sets of criteria for identification of potential Z-DNA sequences in natural DNA genomes. The prediction of potential Z-DNA tracts and corresponding statistical analysis of their occurrence have been made on a sample of 14 DNA genomes. Alternating purine and pyrimidine tracts longer than 5 base pairs in length and their clusters (quasi alternating fragments) in the 14 genomes studied are under-represented compared to the expectation from corresponding random sequences. The fragments [d(G X C)]n and [d(C X G)]n (n greater than or equal to 3) in general do not occur in circular DNA genomes and are under-represented in the linear DNAs of phages lambda and T7, whereas in linear genomes of adenoviruses they are strongly over-represented. With minor exceptions, potential Z-DNA sites are also under-represented compared to random sequences. In the 14 genomes studied, predicted Z-DNA tracts occur in non-coding as well as in protein coding regions. The predicted Z-DNA sites in phi X174, SV40, pBR322 and PM2 correspond well with those mapped experimentally. A complete listing together with a compact graphical representation of alternating purine-pyrimidine fragments and their Z-forming potential are presented.