Complex changes in serum protein levels in COVID-19 convalescents

The COVID-19 pandemic, triggered by severe acute respiratory syndrome coronavirus 2, has affected millions of people worldwide. Much research has been dedicated to our understanding of COVID-19 disease heterogeneity and severity, but less is known about recovery associated changes. To address this gap in knowledge, we quantified the proteome from serum samples from 29 COVID-19 convalescents and 29 age-, race-, and sex-matched healthy controls. Samples were acquired within the first months of the pandemic. Many proteins from pathways known to change during acute COVID-19 illness, such as from the complement cascade, coagulation system, inflammation and adaptive immune system, had returned to levels seen in healthy controls. In comparison, we identified 22 and 15 proteins with significantly elevated and lowered levels, respectively, amongst COVID-19 convalescents compared to healthy controls. Some of the changes were similar to those observed for the acute phase of the disease, i.e. elevated levels of proteins from hemolysis, the adaptive immune systems, and inflammation. In contrast, some alterations opposed those in the acute phase, e.g. elevated levels of CETP and APOA1 which function in lipid/cholesterol metabolism, and decreased levels of proteins from the complement cascade (e.g. C1R, C1S, and VWF), the coagulation system (e.g. THBS1 and VWF), and the regulation of the actin cytoskeleton (e.g. PFN1 and CFL1) amongst COVID-19 convalescents. We speculate that some of these shifts might originate from a transient decrease in platelet counts upon recovery from the disease. Finally, we observed race-specific changes, e.g. with respect to immunoglobulins and proteins related to cholesterol metabolism.

Proteomic Signatures of the Serological Response to Influenza Vaccination in a Large Human Cohort Study

The serological response to the influenza virus vaccine is highly heterogeneous for reasons that are not entirely clear. While the impact of demographic factors such as age, body mass index (BMI), sex, prior vaccination and titer levels are known to impact seroconversion, they only explain a fraction of the response. To identify signatures of the vaccine response, we analyzed 273 protein levels from 138 serum samples of influenza vaccine recipients (2019-2020 season). We found that levels of proteins functioning in cholesterol transport were positively associated with seroconversion, likely linking to the known impact of BMI. When adjusting seroconversion for the demographic factors, we identified additional, unexpected signatures: proteins regulating actin cytoskeleton dynamics were significantly elevated in participants with high adjusted seroconversion. Viral strain specific analysis showed that this trend was largely driven by the H3N2 strain. Further, we identified complex associations between adjusted seroconversion and other factors: levels of proteins of the complement system associated positively with adjusted seroconversion in younger participants, while they were associated negatively in the older population. We observed the opposite trends for proteins of high density lipoprotein remodeling, transcription, and hemostasis. In sum, careful integrative modeling can extract new signatures of seroconversion from highly variable data that suggest links between the humoral response as well as immune cell communication and migration.

Aspartate-407 in Rhodobacter sphaeroides cytochrome c oxidase is not required for proton pumping or manganese binding

Several pathways for proton transport in cytochrome c oxidase have been proposed on the basis of mutational analysis and X-ray structure: at least one for moving "pumped" protons from the interior to exterior of the membrane and a separate route for transporting "substrate" protons from the interior to the binuclear metal center to combine with oxygen to make H2O. According to the crystal structures of cytochrome c oxidase, Asp407 (Rhodobacter sphaeroides numbering) is at the interface of subunit I and subunit II of the oxidase, in a negative patch proposed to be the proton exit site in a pumping pathway, as well as a possible ligand to Mg [Iwata et al. (1995) Nature 376, 660-669]. Three mutants at the Asp407 position of R. sphaeroides cytochrome oxidase, Asp407Ala, Asp407Asn, and Asp407Cys, have been purified and characterized. All showed electron transfer activity, and pH dependence of activity, similar to that of the wild type enzyme and no major structural changes, as evidenced by visible, EPR, and resonance Raman spectroscopy. When reconstituted into artificial vesicles, the purified mutants pumped protons with normal efficiency and responded to the membrane pH and electrical gradients in a manner similar to that of wild type. Furthermore, the EPR spectra and Mn quantitation analysis of mutants grown in high Mn indicated no significant alteration in the Mn/Mg site. These results suggest that Asp407 does not play a critical role in proton translocation or in Mn/Mg binding.

[Clinical relevance of signal-intense foci in cerebral magnetic resonance tomography in neurofibromatosis]

37 patients with documented neurofibromatosis (15 children and 22 adults) had MR examination of the cerebrum. To determine the clinical relevance of signalintense foci in MRT EEG, BAEP and a neuropsychological test batteries was carried out. Our investigations showed that signalintense areas, which possibly represent dysplastic lesions, did not correlate with neurological deficits, epileptic seizures and cognitive disabilities. It remains unclear whether these lesions are of a potential malignancy.

[Cerebral MRT in neurofibromatosis: gliosis versus neoplasia?]

15 patients aged 1-39 years with documented neurofibromatosis had MR examinations of the cerebrum within the scope of a basic diagnosis and therapy programme. Clinical examination did not lead to pathologic findings for 7 of the patients; 3 patients suffered from general developmental disabilities. A neurologico-psychiatric examination showed pathological findings in 5 patients. Signal-intense foci in proton density and T2-weighted MR images were found in the globus pallidus, thalamus, hippocampus, cerebellum and midbrain. In 2 patients, these foci could be found as well in T1-weighted images. Differentiation between gliosis areas and low grade astrocytomas was not possible in MR.

[MR tomography of the elbow joint]

MR examinations of the elbow joint of three healthy subjects and a comparison with corresponding sections of anatomical preparations show that MR tomography enables not only an excellent differentiation of muscles, tendons and of the articular capsule, but will also visualise vessels and nerve tracts. MR tomography proved superior to the conventional methods in demonstration of separate fragments and inflammatory changes in the bone on examining 11 pathological elbow joints: congenital malformation, osteochondritis dissecans, ostitis, ulnar and radial nerve lesions, completely healed radius fracture and epicondylitis of the radial and ulnar humerus. Epicondylitis could not be demonstrated by MR. Magnetic resonance tomography seems to be the only method that enables direct visualisation of the nerve paths at the elbow joint.

[Vertebral hemangioma with extradural spinal cord compression. Clinico-radiologic and NMR findings]

A haemangioma extending from the first thoracal vertebra into the extradural spinal canal presented clinically as slowly progressive incomplete cord compression. Radiographic, myelographic, and CT findings are demonstrated and an additional lumbar vertebral haemangioma was found. The study of magnetic resonance imaging (MRI) done by spin-echo technique indicated that signal intensities within the vascular malformation measured in various recovery (TR) and echo times (TE) are largely the result of different blood flow velocities.

[Value of nuclear medicine and ultrasonography in the management of renal trauma (author's transl)]

Intravenous urography remains the most decisive investigative method in the management of blunt renal trauma. Even minor urographical changes would merit scintiscan and ultrasound examination in order to visualize or rule out parenchymal lesions, intra- or extrarenal hematomas and urine extravasation as well as assess respirational excursions of the kidney. Follow-up studies may be performed without hesitation. Major lesions (primarily a urinoma) and alarming clinical findings necessitate further diagnostic procedures (angiography, possibly after computer tomography). In case of a surgical intervention, angiography cannot be replaced by any other diagnostic method to date. There are no comparative studies of patients with similar injuries managed alternatively with immediate operation or a conservative approach. However, based on our diagnostic possibilities and therapeutical results, we are in favor of a more expectant management of major renal trauma.

[Correction of divided renal clearance studies--a comparison of renal depths (author's transl)]

Differences in renal depth can be determined by ultrasound investigation and profile measurements of a digitalised lateral renal scintigram. Both methods are simple and equally suitable for determining renal depth. Amongst 42 patients there were three in whom there were considerable differences in renal depth in the supine position, and seven patients with a similar difference when they were sitting upright. A correction for renal depth resulted in a reduction in the error obtained on divided renal clearance studies. Measurements on a renal phantom designed to obtain the half-value layer of 131I and 99mTc provide quantitative data for the correction. The correction is less easily carried out when renal depth differences occur in the sitting position than when the patient was lying down. Determination of renal depth when the patient is lying down can be confined to individual cases which can be selected from the total clinical material.