Estimates of protection levels against SARS-CoV-2 infection and severe COVID-19 in Germany before the 2022/2023 winter season: the IMMUNEBRIDGE project

PURPOSE

Despite the need to generate valid and reliable estimates of protection levels against SARS-CoV-2 infection and severe course of COVID-19 for the German population in summer 2022, there was a lack of systematically collected population-based data allowing for the assessment of the protection level in real time.

METHODS

In the IMMUNEBRIDGE project, we harmonised data and biosamples for nine population-/hospital-based studies (total number of participants n = 33,637) to provide estimates for protection levels against SARS-CoV-2 infection and severe COVID-19 between June and November 2022. Based on evidence synthesis, we formed a combined endpoint of protection levels based on the number of self-reported infections/vaccinations in combination with nucleocapsid/spike antibody responses ("confirmed exposures"). Four confirmed exposures represented the highest protection level, and no exposure represented the lowest.

RESULTS

Most participants were seropositive against the spike antigen; 37% of the participants ≥ 79 years had less than four confirmed exposures (highest level of protection) and 5% less than three. In the subgroup of participants with comorbidities, 46-56% had less than four confirmed exposures. We found major heterogeneity across federal states, with 4-28% of participants having less than three confirmed exposures.

CONCLUSION

Using serological analyses, literature synthesis and infection dynamics during the survey period, we observed moderate to high levels of protection against severe COVID-19, whereas the protection against SARS-CoV-2 infection was low across all age groups. We found relevant protection gaps in the oldest age group and amongst individuals with comorbidities, indicating a need for additional protective measures in these groups.

SARS-CoV-2 sero-immunity and quality of life in children and adolescents in relation to infections and vaccinations: the IMMUNEBRIDGE KIDS cross-sectional study, 2022

PURPOSE

The study evaluates the effects on sero-immunity, health status and quality of life of children and adolescents after the upsurge of the Omicron variant in Germany.

METHODS

This multicenter cross-sectional study (IMMUNEBRIDGE Kids) was conducted within the German Network University Medicine (NUM) from July to October 2022. SARS-CoV-2- antibodies were measured and data on SARS-CoV-2 infections, vaccinations, health and socioeconomic factors as well as caregiver-reported evaluation on their children's health and psychological status were assessed.

RESULTS

497 children aged 2-17 years were included. Three groups were analyzed: 183 pre-schoolchildren aged 2-4 years, 176 schoolchildren aged 5-11 years and 138 adolescents aged 12-18 years. Positive antibodies against the S- or N-antigen of SARS-CoV-2 were detected in 86.5% of all participants (70.0% [128/183] of pre-schoolchildren, 94.3% of schoolchildren [166/176] and 98.6% of adolescents [136/138]). Among all children, 40.4% (201/497) were vaccinated against COVID-19 (pre-schoolchildren 4.4% [8/183], schoolchildren 44.3% [78/176] and adolescents 83.3% [115/138]). SARS-CoV-2 seroprevalence was lowest in pre-school. Health status and quality of life reported by the parents were very positive at the time of the survey (Summer 2022).

CONCLUSION

Age-related differences on SARS-CoV-2 sero-immunity could mainly be explained by differences in vaccination rates based on the official German vaccination recommendations as well as differences in SARS-CoV-2 infection rates in the different age groups. Health status and quality of life of almost all children were very good independent of SARS-CoV-2 infection and/or vaccination.

TRIAL REGISTRATION

German Registry for Clinical Trials Identifier Würzburg: DRKS00025546 (registration: 11.09.2021), Bochum: DRKS00022434 (registration:07.08.2020), Dresden: DRKS 00022455 (registration: 23.07.2020).

Long-Term Antibody Response to SARS-CoV-2 in Children

Almost 2 years into the pandemic and with vaccination of children significantly lagging behind adults, long-term pediatric humoral immune responses to SARS-CoV-2 are understudied. The C19.CHILD Hamburg (COVID-19 Child Health Investigation of Latent Disease) Study is a prospective cohort study designed to identify and follow up children and their household contacts infected in the early 2020 first wave of SARS-CoV-2. We screened 6113 children < 18 years by nasopharyngeal swab-PCR in a low-incidence setting after general lockdown, from May 11 to June 30, 2020. A total of 4657 participants underwent antibody testing. Positive tests were followed up by repeated PCR and serological testing of all household contacts over 6 months. In total, the study identified 67 seropositive children (1.44%); the median time after infection at first presentation was 83 days post-symptom onset (PSO). Follow-up of household contacts showed less than 100% seroprevalence in most families, with higher seroprevalence in families with adult index cases compared to pediatric index cases (OR 1.79, P = 0.047). Most importantly, children showed sustained seroconversion up to 9 months PSO, and serum antibody concentrations persistently surpassed adult levels (ratio serum IgG spike children vs. adults 90 days PSO 1.75, P < 0.001; 180 days 1.38, P = 0.01; 270 days 1.54, P = 0.001). In a low-incidence setting, SARS-CoV-2 infection and humoral immune response present distinct patterns in children including higher antibody levels, and lower seroprevalence in families with pediatric index cases. Children show long-term SARS-CoV-2 antibody responses. These findings are relevant to novel variants with increased disease burden in children, as well as for the planning of age-appropriate vaccination strategies.

Acceptance of Different Self-sampling Methods for Semiweekly SARS-CoV-2 Testing in Asymptomatic Children and Childcare Workers at German Day Care Centers: A Nonrandomized Controlled Trial

IMPORTANCE

Closure of day care centers (DCCs) to contain the COVID-19 pandemic has been associated with negative effects on children's health and well-being.

OBJECTIVE

To investigate the acceptance of self-sampling methods for continuous SARS-CoV-2 surveillance among asymptomatic children and childcare workers (CCWs) in DCCs.

DESIGN, SETTING, AND PARTICIPANTS

This nonrandomized pilot study included children and CCWs at 9 DCCs in Wuerzburg, Germany, from May to July 2021.

INTERVENTIONS

Twice weekly testing for SARS-CoV-2 was conducted by self-sampled mouth-rinsing fluid (saliva sampling [SAL], with subsequent pooled polymerase chain reaction test) plus nasal rapid antigen self-test (RAgT) (group 1), SAL only (group 2), or RAgT only (group 3) in children and CCWs.

MAIN OUTCOMES AND MEASURES

Main outcomes were rates for initial acceptance and successful (≥60% of scheduled samples) long-term participation. The probability of SARS-CoV-2 introduction into DCCs was modeled as a function of age-adjusted background incidence and DCC size.

RESULTS

Of 836 eligible children, 452 (54.1%; 95% CI, 50.7%-57.4%) participated (median [IQR] age: 4 [3-5] years; 213 [47.1%] girls), including 215 (47.6%) in group 1, 172 (38.1%) in group 2, and 65 (14.4%) in group 3. Of 190 CCWs, 139 (73.2%; 95% CI, 66.4%-79.0%) participated (median [IQR] age: 30 [25-46] years; 128 [92.1%] women), including 96 (69.1%) in group 1, 29 (20.9%) in group 2, and 14 (10.1%) in group 3. Overall, SARS-CoV-2 PCR tests on 5306 SAL samples and 2896 RAgTs were performed in children, with 1 asymptomatic child detected by PCR from SAL. Successful long-term participation was highest in group 2 (SAL only; children: 111 of 172 [64.5%]; CCWs: 18 of 29 [62.1%]). Weekly participation rates in children ranged from 54.0% to 83.8% for SAL and from 44.6% to 61.4% for RAgT. Participation rates decreased during the study course (P < .001). The probability of SARS-CoV-2 introduction into a DCC with 50 children was estimated to reach at most 5% for an age-adjusted SARS-CoV-2 incidence below 143.

CONCLUSIONS AND RELEVANCE

Self-sampling for continuous SARS-CoV-2 testing was well accepted, with SAL being the preferred method. Given the high number of negative tests, thresholds for initiating continuous testing should be established based on age-adjusted SARS-CoV-2 incidence rates.

TRIAL REGISTRATION

German Registry for Clinical Trials Identifier: DRKS00025546.

Parents’ and Childcare Workers’ Perspectives Toward SARS-CoV-2 Test and Surveillance Protocols in Pre-school Children Day Care Centers: A Qualitative Study Within the German Wü-KiTa-CoV Project

Background

Feasibility of surveillance through continuous SARS-CoV-2 testing in pre-school children and childcare workers (CCWs) to prevent closure of day care centers (DCCs) was proven in the Wü-KiTa-CoV study. The purpose of this study was to describe the factors that facilitate or hinder the implementation of continuous SARS-CoV-2 testing from the perspective of parents and CCWs involved in the study.

Methods

A total of 148 semi–structured telephone interviews, repeated before and after the implementation of the surveillance protocols, were conducted with parents and CCWs belonging to the DCCs involved in Wü-KiTa-CoV and analyzed using qualitative content analysis.

Results

Five main topical categories that influences implementation of surveillance protocols for SARS-CoV-2 in DCCs emerged: Generating valuable knowledge, Impact on daily life, Communication and information, Children’s wellbeing and the Sense of security. Smooth integration in daily routines, quickly delivered test results, and efficient communication and information between the study team and the participants were identified as factors that had a positive impact on implementation. To ensure children’s wellbeing, the introduction of non-invasive testing procedures such as saliva testing, parental involvement to motivate, and prepare children for the procedure, the creation of a child-friendly environment for testing, and use of child-friendly explanations were considered critical. The surveillance was found to increase the sense of security during the pandemic. Conversely, reliability of tests in the surveillance protocols, low participation rates, non-transparent communication, the need to travel to testing sites, fear of quarantine in case of positive test results, concerns about higher workloads, the fear of unpleasant feelings for children, their young age, and changing test teams were considered as hindering factors.

Conclusion

This qualitative study of parents of children in day care and DCC staff under surveillance through continuous testing for SARS-CoV-2 in nine German DCCs identified several factors that facilitate or hinder its implementation. These should be considered when planning screening interventions to prevent the spread of SARS-CoV-2 or other infectious diseases in pre-school children DCCs.

Very Low Incidence of SARS-CoV-2, Influenza and RSV but High Incidence of Rhino-, Adeno- and Endemic Coronaviruses in Children With Acute Respiratory Infection in Primary Care Pediatric Practices During the Second and Third Wave of the SARS-CoV-2 Pandemic

Respiratory viruses were detected by multiplex-polymerase chain reaction from oropharyngeal swabs in 114/168 (67.9%) children with acute respiratory infection presenting to 5 pediatric practices in Germany between November 2020 and April 2021. In contrast to rhino- (48.8%), adeno- (14.3%) and endemic coronaviruses (14.9%), SARS-CoV-2 and influenza virus were detected only once; respiratory syncytial virus was not detected. This demonstrates differing impacts of pandemic infection control measures on the spread of respiratory viruses.

Maternal versus paternal living kidney transplant donation is associated with lower rejection in young pediatric recipients: A Collaborative Transplant Study report

BACKGROUND

Approximately 1700 children per year with end-stage kidney disease undergo kidney transplantation in Europe and the United States of America; 30%-50% are living donor kidney transplantations. There may be immunological differences between paternal and maternal donors due to transplacental exchange of cells between the mother and fetus during pregnancy leading to microchimerism. We investigated whether the outcome of living-related kidney transplantation in young children is different after maternal compared with paternal organ donation.

METHODS

Using the international Collaborative Transplant Study (CTS) database, we analyzed epidemiological data of 7247 children and adolescents aged <18 years who had received a kidney transplant from either mother or father. Risk of treated rejection episodes and death-censored graft failure were computed using the Kaplan-Meier method and multivariable Cox regression.

RESULTS

In the recipient age group 1-4 years, the rate of treated rejection episodes in recipients of kidneys from maternal donors (N = 195) during the first 2 years post-transplant was significantly lower (hazard ratio HR = 0.47, p = .004) than in patients receiving kidneys from paternal donors (N = 179). This association between donor sex and risk of treated rejections was not observed in children aged 5-9 years. The 5-year death-censored graft survival in children aged 1-4 years with a maternal or paternal donor was comparable.

CONCLUSIONS

Maternal kidney donation in young pediatric renal transplant recipients is associated with an approximately 50% lower rate of treated rejection than paternal kidney donation. Whether this phenomenon is due to maternal microchimerism-induced donor-specific hyporesponsiveness must be evaluated in prospective mechanistic studies.

Feasibility of SARS-CoV-2 Surveillance Testing Among Children and Childcare Workers at German Day Care Centers: A Nonrandomized Controlled Trial

IMPORTANCE

Closure of day care centers has been implemented globally to contain the COVID-19 pandemic but has negative effects on children's health and psychosocial well-being.

OBJECTIVE

To investigate the feasibility of surveillance among children and childcare workers and to model the efficacy of surveillance on viral spread prevention.

DESIGN, SETTING, AND PARTICIPANTS

This nonrandomized controlled trial was conducted at 9 day care centers in Wuerzburg, Germany, from October 2020 to March 2021. Participants included children attending day care, childcare workers, and household members. Participating day care centers were assigned to different surveillance modules in a nonrandomized feasibility study. A mathematical model for SARS-CoV-2 spread in day care centers was developed to identify optimal surveillance.

INTERVENTIONS

Modules 1, 2, and 3 involved continuous surveillance of asymptomatic children and childcare workers by SARS-CoV-2 polymerase chain reaction testing of either midturbinate nasal swabs twice weekly (module 1) or once weekly (module 2) or self-sampled saliva samples twice weekly (module 3). Module 4 involved symptom-based, on-demand testing of children, childcare workers, and their household members by oropharyngeal swabs. All participants underwent SARS-CoV-2 antibody status testing before and after the sampling period. Questionnaires on attitudes and perception of the pandemic were administered in weeks 1, 6, and 12. Mathematical modeling was used to estimate SARS-CoV-2 spread in day care centers.

MAIN OUTCOMES AND MEASURES

The primary outcomes were acceptance of the respective surveillance protocols (feasibility study) and the estimated number of secondary infections (mathematical modeling).

RESULTS

Of 954 eligible individuals (772 children and 182 childcare workers), 592 (62%), including 442 children (median [IQR] age, 3 [2-4] years; 214 [48.6%] female) and 150 childcare workers (median [IQR] age, 29 [25-44] years; 129 [90.8%] female) participated in the surveillance. In total, 4755 tests for SARS-CoV-2 detected 2 infections (1 childcare worker and 1 adult household member). Acceptance for continuous surveillance was highest for biweekly saliva testing (150 of 221 eligible individuals [67.9%; 95% CI, 61.5%-73.7%]) compared with biweekly (51 of 117 individuals [43.6%; 95% CI, 35.0%-52.6%]) and weekly (44 of 128 individuals [34.4%; 95% CI, 26.7%-43.0%]) midturbinate swabbing (P < .001). Dropout rates were higher for midturbinate swabbing (biweekly, 11 of 62 participants [18%]; once weekly, 11 of 55 participants [20%]) than for saliva testing (6 of 156 participants [4%]). Mathematical modeling based on study and literature data identified biweekly testing of at least 50% of children and childcare workers as minimal requirements to limit secondary infections.

CONCLUSIONS AND RELEVANCE

In this nonrandomized controlled trial, surveillance for SARS-CoV-2 in 9 German day care centers was feasible and well accepted. Mathematical modeling estimated that testing can minimize the spread of SARS-CoV-2 in day care centers. These findings enable setup of surveillance programs to maintain institutional childcare.

TRIAL REGISTRATION

German Registry for Clinical Trials Identifier: DRKS00023721.

[Diabetic foot syndrome-Part 2 : Revascularization, treatment alternatives, care structures, recurrency prophylaxis]

Diabetic foot syndrome (DFS) is the most frequent reason for major amputations in Germany. The majority of foot lesions are triggered by repetitive pressure in diabetic polyneuropathy. Peripheral arterial occlusive disease (PAOD) impairs wound healing and is the main risk factor for amputations. The treatment of wounds and infections as well as timely revascularization are decisive. The use of endovascular and vascular surgical methods depends on the distribution pattern and length of the occlusion processes. Both procedures are complementary. Bypass surgery is of great importance for neuroischemic DFS. Multidisciplinary centers that provide revascularization in DFS can achieve an improvement of arterial blood flow in 90% of the cases and reduce the amputation rate by up to 80%. Due to the high recurrence rate of diabetic foot lesions, measures for secondary prophylaxis are of exceptional importance (podological and orthopedic technical care, foot surgery).

[Diabetic foot syndrome-Part 1 : Definition, pathophysiology, diagnostics and classification]

There are ca. 8 million persons with diabetes mellitus living in Germany. A late sequelae of diabetes is the diabetic foot syndrome (DFS), the prevalence of which is greatly increasing. It comprises all alterations of the foot as a result of diabetic polyneuropathy as well as microvascular and macrovascular (peripheral arterial occlusive disease, PAOD) alterations. Many of the ca. 250,000 newly diagnosed diabetic foot ulcers per year become chronic wounds. Despite intensive efforts for prevention, early diagnosis and adequate wound care, ca. 13,000 persons with diabetes undergo major limb amputation in Germany every year. With consistent treatment in interdisciplinary centers and by exhausting all possible methods of wound treatment, pressure relief as well as arterial revascularization, the major amputation rate in patients with diabetic foot problems can be reduced by 80%. With a suitable strategy of prevention, the recurrence rate of foot ulcers would be reduced.

Influenza pathogenicity during pregnancy in women and animal models

Pregnant women are at the highest risk to develop severe and even fatal influenza. The high vulnerability of women against influenza A virus infections during pregnancy was repeatedly highlighted during influenza pandemics including the pandemic of this century. In 2009, mortality rates were particularly high among otherwise healthy pregnant women. However, our current understanding of the molecular mechanisms involved in severe disease development during pregnancy is still very limited. In this review, we summarize the knowledge on the clinical observations in influenza A virus-infected pregnant women. In addition, knowledge obtained from few existing experimental infections in pregnant animal models is discussed. Since clinical data do not provide in-depth information on the pathogenesis of severe influenza during pregnancy, adequate animal models are urgently required that mimic clinical findings. Studies in pregnant animal models will allow the dissection of involved molecular disease pathways that are key to improve patient management and care.

Mutational and expression analysis of CDK1, cyclinA2 and cyclinB1 in epilepsy-associated glioneuronal lesions

Gangliogliomas and focal cortical dysplasias (FCDs) constitute glioneuronal lesions, which are frequently encountered in biopsy specimens of patients with pharmacoresistant focal epilepsy and relate to impaired differentiation and migration of neural precursors. However, their molecular pathogenesis and relationship are still largely enigmatic. Recent data suggest several components of the insulin-pathway, including TSC1 and TSC2 mutated in tuberous sclerosis complex (TSC), to be altered in gangliogliomas and FCD with Taylor type balloon cells (FCD(IIb)). The proteins tuberin (TSC2) and hamartin (TSC1) constitute a tumour suppressor mechanism involved in cell-cycle control. Hamartin and/or tuberin were reported to colocalize and/or interact with CDK1, cyclinB1 and cyclinA2 that are critically involved in cell-size and cell-growth control. Here, we have carried out mutational and expression analyses of CDK1, cyclinB1 and cyclinA2 in gangliogliomas and FCD(IIb). Mutational screening was performed by single-strand conformation polymorphism analysis in gangliogliomas (n = 20), FCD(IIb) (n = 35) and controls. CyclinB1 revealed a polymorphism (G to A, cDNA Position 966, GenBank: NM_031966) in exon 7 with similar frequencies in FCD(IIb), gangliogliomas and control specimens (FCD n = 9/35; gangliogliomas n = 5/20; control n = 20/100). We used real-time reverse transcription polymerase chain reaction to determine expression levels of CDK1, cyclinB1 and cyclinA2 in 10 FCD(IIb) and nine gangliogliomas compared with unaffected adjacent control tissue of the same patients. We observed significantly lower expression of CDK1 and cyclinA2 in FCD(IIb) vs. controls whereas no significant expression differences were present for CDK1, cyclinB1 and cyclinA2 in gangliogliomas. Our data strongly argue against mutational events of CDK1, cyclinB1 and cyclinA2 to play a role in gangliogliomas or FCD(IIb). However, a potential functional significance of lower expression for the cell-size and cell-cycle regulators CDK1 and cyclinA2 in FCD(IIb) composed of large dysplastic neurones and balloon cells needs to be further resolved.

The HLA-G genotype is potentially associated with idiopathic recurrent spontaneous abortion

The causes for recurrent spontaneous abortion (RSA) remain unknown in a large proportion of the cases. Human leukocyte antigen (HLA)-G and HLA-E are expressed on invasive trophoblast cells, and are supposed to confer to materno-fetal tolerance. A total of 14 different nucleotide sequences have been described for HLA-G, including one dysfunctional null allele (HLA-G*0105N), while five different sequences have been described for HLA-E. In this study, 78 RSA couples and 52 fertile controls were typed for HLA-G and HLA-E by direct sequencing or single strand conformational polymorphism (SSCP) respectively. The overall analysis showed no significant difference in allele frequencies for either HLA-G or HLA-E between the two groups. However, HLA-G allele frequencies in women who had suffered from five or more RSA differed significantly from fertile controls (P: = 0.001), and from women who had undergone three or four RSA (P: = 0.027). Detailed analysis demonstrated a significant increase in the proportion of the HLA-G alleles *01013 and *0105N in the whole group of RSA women compared with fertile controls (P: = 0.007). When studying the prognostic value of HLA genotyping for pregnancy outcome (n = 41), 31 patients (76%) gave birth to a living child without performing immunotherapy. Seven out of 10 (70%) couples suffering from a further RSA carried the HLA-G*01013 or *0105N allele, compared with 10 out 31 (32%) couples giving birth (P: = 0.06). This study suggests that the HLA-G genotype may be a contributing factor in RSA.

Evidence for major histocompatibility complex-mediated effects on spermatogenesis in humans

Studies in fertile and infertile populations suggest an influence of genes of the major histocompatibility complex (MHC) on reproduction, although it remains unresolved if MHC-mediated effects on fertility are based on direct immunological or non-immunological effects of human leukocyte antigen (HLA) genes or rather on defects in MHC-associated non-HLA genes which affect gamete quality and embryonic development. We analysed allele frequencies for HLA class II loci DQA1, DQB1 and DRB1 and HLA class II haplotype frequencies in couples with tubal and andrological infertility who were treated with assisted reproductive techniques. Males with severe andrological infertility had significantly different allele frequencies for all three HLA loci when compared to males with normozoospermia, whereas no difference was found in the females. Differences in allele frequencies were stronger when only males whose partners achieved pregnancies after assisted reproduction treatment were compared. In those subgroups, we could also observe significant differences in three locus HLA class II haplotype frequencies. In summary, patients with male factor infertility differ in their HLA class II allele constitution from males with normozoospermia, which suggests that genes identical to or located in close vicinity to HLA class II genes may influence spermatogenesis and male gamete function.

HLA-G polymorphisms and allele frequencies in Caucasians

HLA-G, a nonclassical class I MHC molecule, is uniquely expressed on extravillous cytotrophoblasts of the maternal-fetal interface and is suggested to be essential for establishment of maternal-fetal immune tolerance. Although the level of polymorphism in HLA-G has originally been considered low, number, nature and site of polymorphisms seem to vary between different ethnic populations. We investigated HLA-G polymorphisms in a population of German and Croatian origin by SSCP-analysis and direct sequencing as well as RFLP analysis for presence of the 1597delC mutation. HLA-A alleles associated with the different HLA-G alleles were determined by SSP PCR-typing. In Caucasians, HLA-G exhibits a low degree of polymorphism on the amino-acid level and only slightly higher variability on the nucleotide level. In 264 independent chromosomes, 4 HLA-G alleles on the level of amino acid polymorphisms and an additional 6 variations of nucleotide sequences could be identified. The null-allele G*0105N was present at an allele frequency of 2.3%, which is higher than initially suggested for Caucasians but lower than in Hispanics and African-Americans. Furthermore, some HLA-G alleles exhibit strong linkage disequilibrium with HLA-A.

The content of parthenolide and its yield per plant during the growth of Tanacetum parthenium

During the growth of Tanaceum parthenium (L.) Schultz-Bip. Feverfew, Asteraceae) the percentage of parthenolide was the highest at an early stage (just before the formation of stems). The yield of parthenolide per individual plant gradually increased from about 10 mg at the beginning of the study to about 20 mg when the plant was in full bloom. Parthenolide was present in the leaves and flowerheads, but not in the stems. Drying at ambient temperature and lyophilisation had no negative influence on the yield of parthenolide per individual plant on comparing the results with those of fresh plant material. Based on the results of this study and on data from the literature we propose to distinguish two qualities of feverfew: a: Tanaceti parthenii folium (feverfew leaf), harvested at an early stage before the formation of the stems and b: Tanaceti parthenii herba (feverfew herb), harvested at full bloom, with a minimum parthenolide content of 0.50% and 0.20%, respectively, calculated on a dry weight basis. Both drugs can be easily distinguished by means of microscopic examination.

Posterior fossa neurovascular anomalies in essential hypertension

Intraoperative observations, necropsy, and angiographic studies support the presumption that neurovascular compression of the left ventrolateral medulla may cause neurogenic hypertension. Pulsatile irritation of the ventrolateral medulla at the root-entry zone of cranial nerves IX and X increases blood pressure in animals. To identify and assess the distribution of neurovascular compression at the ventrolateral medulla in human beings, we did a prospective single-blind study in 24 patients with essential hypertension, in 14 patients with renal hypertension, and in 14 normal subjects. To detect neurovascular compression, we used axial and coronal double-echo and magnetic-resonance angiography sequences. Blood pressure control and duration of hypertension were not different in the two groups of patients. 20 patients with essential hypertension had magnetic tomographic evidence of left-sided neurovascular compression at the ventrolateral medulla; 2 patients with renal hypertension and 1 of the normal subjects had a positive finding on the left. On the right side, we found signs of neurovascular compression in 4 patients with essential hypertension, in 4 with renal hypertension, and in 2 of the normal subjects. With magnetic resonance tomography, it is possible to evaluate the neurovascular relations in the posterior fossa and detect neurovascular compression at the ventrolateral medulla. These data in living subjects give further evidence of an association between neurovascular compression at the left ventrolateral medulla and essential hypertension.

[Quantitative evaluation of myocardial perfusion with ultrafast magnetic resonance tomography]

With the advent of ultrafast Magnetic Resonance Imaging (MRI), it is now possible to produce images with high temporal resolution. This gives the opportunity to record the passage of the paramagnetic contrast material Gadolinium-DTPA through the tissue of the heart muscle, yielding information on regional myocardial perfusion. We assessed the accuracy of MRI to detect and quantify reductions in coronary flow secondary to stenosis in dogs and patients. Regional blood flow was measured in dogs by left atrial injection of microspheres labeled with different radioactive isotopes. Signal intensity (SI) curves were generated in regions of interest over the myocardium and the cavum of the left ventricle. A newly developed two-compartment model based on the indicator-dilution method was used for interpretation of the SI-curves. In an optimization process the free parameters of the model equation were fitted to the measured SI-curves. The following flow parameters were determined: model parameter Q*, time to peak intensity (T), maximum signal intensity (SImax) and mean transit time (MTT) as calculated from a gamma variate fit. Absolute blood flow values were calculated for the parameters MTT and Q* assuming that the intravascular volume represents 10% of the total myocardial tissue volume. Measurements were performed on a 1.5 T Magnetom SP (Siemens AG, Erlangen) using a Turbo Flash sequence (TR = 6.5 ms, TE = 3 ms, TI = 100 ms, Flip Winkel = 9 degrees). Endsystolic images (voxel size = 1.8, 2.7, 15 mm3) were taken with an 18-cm Helmholtz surface coil in the short-axis view. A Gd-DTPA bolus (0.05 mmol/kg) was injected into the left atrium of 3 anesthetized closed-chest dogs. From the myocardial SI-curves the different parameters of myocardial perfusion were compared with flow assessed by microsphere injection over a wide range of myocardial blood flows (from 0.04 ml/min/g to 7.6 ml/min/g). A third-order polynominal fit showed a good correlation for the parameter Q* and MTT, whereas T and SImax were found to have a poor correlation. The linear regression analysis for a limited range of < 2 ml/min/g showed a superior estimation of myocardial perfusion for the parameter Q* than MTT. Blood flow > 2 ml/min/g was significantly underestimated by the MRT-measurements, but the parameter Q* showed the smallest amount of the divergent changes.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenal carcinoma with intravenous extension into the tricuspid valvular plane in a patient with patent foramen ovale

We report on an adrenal carcinoma growing via the inferior vena cava into the right atrium and prolapsing into the right ventricle. A patent foramen ovale determined the pathophysiological and clinical appearance. Instead of an expected caval congestion the main features were paroxysmal dyspnoea and cyanosis. The patient was investigated using echocardiography, magnetic resonance tomography and angiography.

Nitrendipine vs. captopril in essential hypertension: effects on circadian blood pressure and left ventricular hypertrophy

Both nitrendipine and captopril have been shown to reverse left ventricular hypertrophy in hypertensive patients. So far, no study allowed a true comparison of these drugs in this regard and with respect to their potential of reducing circadian blood pressure. Therefore, a total of 86 patients with newly diagnosed arterial hypertension and echocardiographic evidence of left ventricular hypertrophy underwent randomized treatment with captopril (n = 43) or nitrendipine (n = 43). Eighteen patients had to be put on a combination therapy of nitrendipine and captopril during the course of the study to control blood pressure effectively. Before and after the 6th and 38th weeks of treatment all patients underwent ambulatory 24-hour blood pressure monitoring, M-mode echo assessment of left ventricular mass and Doppler evaluation of left ventricular filling. The 24-hour blood pressure data were smoothed with a Fourier series and then compared with a normotensive reference profile with respect to blood pressure load and variability. The daytime and nighttime mean and the office blood pressure were also analyzed. Substance-specific profiles of action were obtained by subtracting the smoothed profiles after therapy from the profiles before therapy. After 38 weeks ambulatory blood pressure had decreased from 152 +/- 11/101 +/- 7 to 137 +/- 13/87 +/- 10 mm Hg on nitrendipine and from 147 +/- 11/99 +/- 6 to 134 +/- 13/89 +/- 9 mm Hg on captopril. The substance-specific profiles calculated for captopril and nitrendipine showed a balanced antihypertensive effect throughout the day and the night. The mean percentage decreases in left ventricular muscle mass under nitrendipine was 15% and did not differ significantly from the decrease of 21% under treatment with captopril (p < 0.001). There is no significant association between the reduction in blood pressure and the regression of left ventricular hypertrophy. In patients with disturbances of left ventricular diastolic function the early-to-late diastolic left ventricular flow ratio and the isovolumetric relaxation time were improved independent of the drug used. It is concluded that a long-term therapy with captopril and nitrendipine leads to a comparable degree of circadian blood pressure reduction and regression of hypertensive left ventricular hypertrophy.

[Digital subtraction angiocardiography: reliability of densitometric determination of left ventricular volume and ejection fraction]

The angiographic assessment of left ventricular volume (LV) and ejection fraction (EF) by means of the area-length method (ALM) is based upon geometric assumptions, which might lead to erroneous results. With the development of digital subtraction angiocardiography in real-time, densitometric procedures of calculating left ventricular parameters can be used on-line. This study examines both reliability and accuracy of a densitometric technique for evaluating LV and EF in comparison to the single-plane ALM. Contrast images of heart casts and left ventricular angiograms of 54 patients suffering from different cardiac diseases were obtained by the image acquisition and processing system Polytron 1000 VR (Siemens AG, Erlangen, FRG). Digital images of both heart casts and patients were evaluated densitometrically and geometrically by two independent observers. In the phantom study the densitometric method exhibited a significantly (p < 0.01) better agreement with the true values than the ALM. The evaluation of left ventricular angiograms in patients comparing densitometry with the ALM demonstrated a relatively high residual deviation (enddiastolic volume Syx = +/- 27 ml, endsystolic volume Syx = +/- 19.4 ml). This is mainly due to systematic, method-related errors of densitometry and the morphometric technique. The intra- and interobserver variability in calculating EF showed a significantly (p < 0.05) smaller residual deviation for densitometry than for ALM; no significant differences were found for the calculation of LV. In conclusion, we demonstrated that the presented densitometric technique offers an objective and simple means of determining LV and EF with comparable reliability and validity to the area-length method.

[Quantitative evaluation of aortic valve insufficiency in magnetic resonance tomography]

Flow-encoded magnetic resonance (MR) sequences allow the quantitative evaluation of blood flow in any plane of the heart and vessels. For the first time, ejection and regurgitation volumes of the left ventricle in the ascending aorta can be measured noninvasively. Thus, the regurgitation fraction as a reliable measure of aortic valve insufficiency can be determined. The quantitative evaluation of aortic valve insufficiency was done by MR in comparison to ultrasound-Doppler and, in some cases, in comparison to heart catheterization. A good correlation of grading aortic valve insufficiency by the new MR-technique in comparison to clinical graduation is shown. The development of a new noninvasive standard for quantification of aortic valve insufficiency seems possible.

A new approach for evaluating circadian blood pressure levels and variability from 24 h ambulatory blood pressure profiles

In 24 h blood pressure monitoring the severity of arterial hypertension is generally classified on the basis of the arithmetic mean of the diastolic blood pressure between 6 AM and 10 PM. In the present study Fourier analysis was used for evaluation of circadian blood pressure level and variability. A common reference profile was calculated on the basis of a group of 50 normotensive profiles. This reference profile is characterized by the fact that the sum of the squares of the distances between the individual profiles and the reference profile is a minimum. The individual 24 h profiles of 103 patients with untreated arterial hypertension were also each described by a Fourier series and were then compared with the normotensive reference profile. The comparison was made not only with respect to the absolute pressure over 24 h but also with respect to the circadian fluctuations in blood pressure. Our results show that the Fourier analysis of 24 h blood pressure profiles presented here can be used for more precise evaluation of 24 h blood pressure profiles.

[Ambulatory blood pressure monitoring: significance of blood pressure variability for progression of heart hypertrophy]

It is known that ambulatory blood-pressure monitoring gives a better prediction of target organ damage and prognosis than clinical blood pressure. Many studies have found a closer correlation for ambulatory blood pressure with left ventricular hypertrophy than clinical blood pressure. One question that is discussed controversely is whether the variability of blood pressure is also a determinant of target organ damage independent of the average level. In 52 patients with elevated casual blood pressure a 24-h ambulatory blood-pressure measurement (Space Labs 90202) was performed and left ventricular hypertrophy was evaluated by M-mode echocardiography. The following parameters of blood pressure variability were calculated from the profiles: the standard deviation of the mean value, the variation coefficient and the parameter of variability as proposed by Schächinger et al. Furthermore a Fourier analysis of the blood pressure data was performed to quantify blood pressure variability. We found no statistically significant correlation between blood pressure variability and left ventricular mass. However, systolic and diastolic blood pressure level showed a significant correlation with left ventricular hypertrophy (r = 0.45 and r = 0.49, p < 0.05). Thus, blood pressure variability as calculated from the ambulatory, non-invasive blood pressure monitoring is a poor predictor for secondary damage of the heart.

Evaluation of left ventricular inflow and volume by MR

Considerable progress has been achieved during the past few years in the evaluation of intracardial blood flow by MR. Similar to ultrasound Doppler, it is possible now to registrate parameters of left ventricular diastolic filling as E/A ratio, velocity time integral of A- to E-wave (A(area)/E(area)), or isovolumetric relaxation time index. A total of 24 patients (7 women, 17 men, aged 24-69 yr) were examined, 5 of whom suffered from a hypertensive heart disease, 5 from a coronary heart disease, and 7 from mitral valve stenosis of various degree; 7 showed normal findings. E/A-ratio, A(area)/E(area), as well as isovolumetric relaxation time (IVRT) were evaluated by two different examiners on the same day by MR and ultrasound-Doppler, showing correlation factors of .89 for E/A ratio, .67 for A(area)/E(area), and .76 for IVRT in comparing both techniques. Additionally, to test the potential for making left ventricular function diagnoses from MR, time-volume curves for normal cases and patients with hypertrophic and dilated cardiomyopathy were elaborated by a computer-assisted 3D imaging technique. This technique showed good concordance with the results from cardiac catheterization or radionuclide ventriculography.

[Magnetic resonance rheography in comparison to Doppler ultrasonography in the assessment of mitral valve stenosis]

Ultrasound-Doppler-technique and heart catheterization today are used routinely for the evaluation and graduation of mitral valve stenosis. A new magnetic resonance-technique of intracardial blood-flow registration now allows the grading of mitral valve stenosis. Good reliability and practicability of the demonstrated method in comparison with the ultrasound-Doppler-technique is shown. Future development of an alternative, completing magnetic-resonance method for the evaluation of valvular heart disease and shunt diagnosis is expected.

[Ambulatory invasive and noninvasive blood pressure monitoring]

Indirect arterial blood pressure measurement has not changed substantially since its introduction by Riva-Rocci in 1986, Korotkoff in 1905 and Recklinghausen in 1906. Random measurements in the clinic or practice reflect only incompletely the dynamic nature of the blood pressure. Blood pressure recordings by patients themselves have provided more information through better temporal resolution, however, exact characterization of the pressure response throughout the entire day and, in particular, during physical exertion are not enabled; the latter are especially important with regard to diagnosis and treatment of hypertension. In 1966, therefore, radiotelemetric transmission of direct, continuously-measured arterial blood pressure was developed which enabled beat-to-beat registration of blood pressure, outside the laboratory, during normal daily life and sport activities. The initial results showed a marked variability of the blood pressure during the course of the day (Figure 1). Excessive blood pressure increases were observed during exposure to cold, static and dynamic exercise and to a lesser degree during automobile driving and exposure to heat (Figure 3). Recording of the pressure curves via transmission by radiotelemetry shows a high degree of accuracy and temporal resolution, spatial and situational freedom but is invasive and costly in terms of personnel. The same holds true for direct continuous blood pressure registration and storage on a portable tape recorder. Portable, automatic blood pressure measuring units for ambulatory monitoring employ indirect auscultatory or oscillometric recording with a cuff. As compared with the radiotelemetric direct continuous blood pressure measuring method, the indirect method has subordinate temporal resolution, that is, the measurements are only intermittent.(ABSTRACT TRUNCATED AT 250 WORDS)