[Histopathological findings following SARS-CoV-2 infection with and without treatment-Report of three autopsies]

Bei letalem Verlauf einer SARS-CoV-2-Infektion kommt nach bisherigem Kenntnisstand eine Beteiligung mehrerer innerer Organe in Betracht. Im Vordergrund stehen pathologische Befunde im Lungengewebe, berichtet wird aber auch von direkt oder indirekt als Folge einer Infektion mit SARS-CoV‑2 auftretenden (histo-)pathologischen Befunden im Nierengewebe, in der Leber und im Myokard. Der Vergleich der histopathologischen Diagnostik mit konventionell-histologischen Färbungen bei 3 im Zusammenhang mit einer SARS-CoV-2-Infektion verstorbenen Männern zeigt teils identische Befunde und erlaubt Überlegungen zu Chronologie und Pathophysiologie des Krankheitsverlaufes. Zwei Männer wurden intensivmedizinisch invasiv beatmet; ein Mann starb nach 8 Tagen häuslicher Quarantäne ohne Therapie. Es zeigt sich ein großes Spektrum SARS-CoV-2-assoziierter Befunde.

Molecular Dynamics Investigation of gluazo, a Photo-Switchable Ligand for the Glutamate Receptor GluK2

Photochromic ligands (PCLs), defined as photoswitchable molecules that are able to endow native receptors with a sensitivity towards light, have become a promising photopharmacological tool for various applications in biology. In general, PCLs consist of a ligand of the target receptor covalently linked to an azobenzene, which can be reversibly switched between two configurations upon light illumination. Gluazo, as a PCL that targets excitatory amino acid receptors, in its dark-adapted trans iso-form was characterized to be a partial agonist of the kainate glutamate receptor GluK2. Application of UV light leads to the formation of the cis form, with remarkedly reduced affinity towards GluK2. The mechanism of the change of ligand affinity induced by the photoisomerization was unresolved. The presented computational study explains how the isomerization of such a PCL affects the structural changes in the target receptor that lead to its activation.

Ligand photo-isomerization triggers conformational changes in iGluR2 ligand binding domain

Neurological glutamate receptors bind a variety of artificial ligands, both agonistic and antagonistic, in addition to glutamate. Studying their small molecule binding properties increases our understanding of the central nervous system and a variety of associated pathologies. The large, oligomeric multidomain membrane protein contains a large and flexible ligand binding domains which undergoes large conformational changes upon binding different ligands. A recent application of glutamate receptors is their activation or inhibition via photo-switchable ligands, making them key systems in the emerging field of optochemical genetics. In this work, we present a theoretical study on the binding mode and complex stability of a novel photo-switchable ligand, ATA-3, which reversibly binds to glutamate receptors ligand binding domains (LBDs). We propose two possible binding modes for this ligand based on flexible ligand docking calculations and show one of them to be analogues to the binding mode of a similar ligand, 2-BnTetAMPA. In long MD simulations, it was observed that transitions between both binding poses involve breaking and reforming the T686-E402 protein hydrogen bond. Simulating the ligand photo-isomerization process shows that the two possible configurations of the ligand azo-group have markedly different complex stabilities and equilibrium binding modes. A strong but slow protein response is observed after ligand configuration changes. This provides a microscopic foundation for the observed difference in ligand activity upon light-switching.

The lipo-facelift: merging the face-lift and liposculpture: eight years experience and a preliminary observational study

BACKGROUND

Since the introduction of the classic submucosal aponeurotic system (SMAS) face-lift, the surgical approach to improve the changes of an aging face has evolved, and significant technical improvements have been made. However, several problems still have not been solved satisfactorily. These problems include facial lipodystrophy and changes in skin and skin texture.

METHODS

The Lipo-Facelift procedure consists of facial liposculpturing performed simultaneously with a biplanar, bivectorial SMAS face-lift procedure. The authors analyzed pre- and postsurgical photographs of 12 patients with a Lipo-Facelift after 3 and 12 months and analyzed their charts for complications. Furthermore, O2C measurement was performed to assess improved microcirculation. The longest follow-up period was 8 years.

RESULTS

The Lipo-Facelift demonstrated very satisfying results. Initial swelling and bruising were seen as well as two cases of wound-healing disorders, but no surgical intervention or revision was needed. The findings show lasting improvement of skin quality and a youthful appearance.

CONCLUSION

The Lipo-Facelift corrects age-related skin and SMAS changes as well as age-related lipodystrophy, improves skin circulation and skin revitalization, and provides a lasting and natural result. The skin quality resulting from simultaneous lipofilling can be explained by improved angiogenesis due to transferred growth factors in the lipoaspirate. Also, differentiation of progenitor cells to fibroblasts and increased production of collagen contribute to firmer skin.

LEVEL OF EVIDENCE IV

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Computational study of synthetic agonist ligands of ionotropic glutamate receptors

Neurological glutamate receptors are among the most important and intensely studied protein ligand binding systems in humans. They are crucial for the functioning of the central nervous system and involved in a variety of pathologies. Apart from the neurotransmitter glutamate, several artificial, agonistic and antagonistic ligands are known. Of particular interest here are novel photoswitchable agonists that would open the field of optogenetics to glutamate receptors. The receptor proteins are complex, membrane-bound multidomain oligomers that undergo large scale functional conformational changes, making detailed studies of their atomic structure challenging. Therefore, a thorough understanding of the microscopic details of ligand binding and receptor activation remains elusive in many cases. This topic has been successfully addressed by theoretical studies in the past and in this paper, we present extensive molecular dynamics simulation and free energy calculation results on the binding of AMPA and an AMPA derivative, which is the basis for designing light-sensitive ligands. We provide a two-step model for ligand binding domain activation and predict binding free energies for novel compounds in good agreement to experimental observations.

Complex regional pain syndrome following spine surgery: clinical and prognostic implications

BACKGROUND

Complex regional pain syndrome (CRPS) has been reported following spinal surgery, but its frequency after spinal surgery is unknown. The aim of this study was to determine the frequency of spinal surgery preceding CRPS and to examine these patients regarding the course of the disease and prognostic factors.

METHODS

We examined 35 CRPS patients regarding the symptoms and signs of CRPS, the type of CRPS (I or II), the origin and grade of the disease, the type of surgeries prior to CRPS onset, the course of the disease, and the therapies following diagnosis of CRPS.

RESULTS

In 6 patients, CRPS began during the postoperative course (lumbar spine surgery, n = 5; cervical spine surgery, n = 1). Four of these patients suffered from CRPS II. The course of the disease in the 6 patients was not different from that of patients with CRPS of other origins. First symptoms of CRPS could be observed 1-14 days after surgery.

CONCLUSIONS

CRPS is a rare complication after spinal surgery, but spinal surgery precedes the onset of CRPS of the lower limb in almost one-third of the cases. The first typical symptoms of CRPS emerge within 2 weeks after spinal surgery.

Effects of sub-perception threshold spinal cord stimulation in neuropathic pain: a randomized controlled double-blind crossover study

BACKGROUND

Recent studies suggest that perception of the paraesthesia elicited by spinal cord stimulation (SCS) is not necessarily required for the pain relieving effect.

OBJECTIVE

The purpose of the study was to determine the effect of sub-perception threshold SCS in patients with neuropathic pain.

METHODS

Ten patients with implanted SCS systems underwent continuous sub-threshold stimulation and no stimulation in a blinded randomized crossover design. Pain scores under these treatment modalities were compared with usual supra-threshold stimulation.

RESULTS

Sub-threshold stimulation elicited significantly lower pain relief than supra-perception threshold SCS. Mean pain scores were 3.6 [max 6.3, min 1.9, standard deviation (SD) 1.3] under supra-threshold stimulation, 5.6 (max 9.0, min 2.4, SD 1.9) under sub-threshold stimulation and 6.4 (max 10.0, min 4.0, SD 2.0) without stimulation.

CONCLUSION

Sub-threshold stimulation under otherwise conventional stimulation parameters has a measurable but not clinically sufficient effect. Thus, the pain relieving effect elicited by SCS is not necessarily linked to the perceptibility of stimulation but may instead be attributed to the intensity of the electric field.

[Liposuction]

Liposuction is one of the most commonly performed procedures in aesthetic surgery. The primary aim is body contouring and not weight reduction. The vast amount of available methods for suctioning subcutaneous fat allows an optimal individual treatment plan, keeping in mind the correct indications. Although liposuction is often offered as a minor and harmless surgery, it is a complex procedure. A thorough training of the surgeon and in-depth knowledge about possible complications is essential. In addition to aesthetic indications liposuction is also a valuable tool in reconstructive surgery. For optimal patient selection the skin elasticity has to be considered during the preoperative assessment. Besides pure volume reduction through liposuction, the regenerative possibilities of adipose tissue are of great interest for basic research and clinical applications. Lipofilling or autologous fat transfer is used for a wide variety of aesthetic and reconstructive procedures. Of special interest is the regenerative and reconstructive potential of adipose-derived stem cells (ADSC).

CRPS I following artificial disc surgery: case report and review of the literature

We report a case of type 1 complex regional pain syndrome (CRPS I) of the left leg following the implantation of an artificial disc type in the L4/5 segment of the lumbar spine using a midline left-sided retroperitoneal approach. This approach included the mobilisation of the sympathetic trunk with incision and resection of the intervertebral disc. The perioperative and immediate postoperative periods were uneventful, but on the second postoperative day the patient complained of a progressive allodynia of the whole left leg in combination with weakness of the limb. Neurological examination did not reveal any radicular deficit or paresis. A sympathetic reaction following the mobilisation of the sympathetic trunk during the ventral preparation of the spine was suspected and investigated further. A diagnosis of CRPS I was proposed, and the patient was treated with analgesia, co-analgesics for pain alienation, and systemic corticosteroid therapy. A computed tomography-guided sympathetic block and lymphatic drainage were performed. Following conservative orthopaedic rehabilitation therapy, the degree of pain, allodynia, weakness, and swelling were reduced and the condition of the patient was ameliorated. The cost-benefit ratio of spinal arthroplasty is still controversial. The utility of this paper is to debate a possible cause of a painful complication, which can invalidate the results of a successful operation.

CT-guided cervical selective nerve root block with a dorsal approach

BACKGROUND AND PURPOSE

Cervical transforaminal blocks are frequently performed to treat cervical radicular pain. These blocks are performed mostly under fluoroscopy, but a CT-guided technique has also been described. The aim of this study was to review the results of CT-guided CSNRB by using a dorsal approach, to describe the contrast patterns achieved with this injection technique, and to estimate the degree of specificity and sensitivity.

MATERIALS AND METHODS

We used a CT-guided technique with a dorsal approach leading to a more extra-than transforaminal but a selective nerve root block as well. Of 53 blocks, we performed 38 for diagnostic and 15 for therapeutic indications. Pain relief was measured hourly on a VAS. The distribution of contrast and the angle of the trajectory of the injection needle were analyzed as well as the degree of pain relief.

RESULTS

Contrast was found in the intraforaminal region in 8 (15%) blocks, extraforaminally in 40 (78%) blocks, and intraspinally in 3 (6%) blocks. The mean angle between the needle and the sagittal plane was 26.6° (range, from 1° to 50°). The mean distance between needle tip and nerve root was 4.43 mm (range, 0-20 mm). Twenty-six (68.4%) of the 38 diagnostic blocks led to a decrease in the pain rating of >50%. There were no complications or unintended side effects, apart from occasional local puncture pain.

CONCLUSIONS

We conclude that CT-guided CSNRBs using a dorsal approach are feasible and that they are sensitive and specific.

Cervical CT-guided, selective nerve root blocks: improved safety by dorsal approach

Cervical transforaminal blocks are frequently performed as a treatment of cervical radicular pain. These blocks are performed mostly under fluoroscopy, but a CT-guided technique also has been described. We describe a modification that leads to a more extraforaminal than transforaminal and equally selective nerve root block.

Interdisciplinary pain therapy: an innovative therapeutic but pre-DRG Economical Center of Medical Excellence

OBJECTIVE

After the implementation of the G-DRG system in Germany, doubts arose whether and how interdisciplinary pain therapy centers should be restructured to remain profitable and maintain medical excellence for patients with a long ordeal of malaise.

METHODS

To reveal structural deficits, we performed a detailed economic analysis of all patients treated at an interdisciplinary pain therapy center of a German University hospital in 2004.

RESULTS

3,672 patients were treated: 2,163 outpatients, 753 at the daycare clinic, 619 as consults and 132 inpatients. The costs for personnel were euro 736,645, consumables euro 105,061, and infrastructure euro 277,762. We calculated fixed costs of euro 236, and consumables of euro 24 per patient. The costs for surgery were euro 1,595, and for a neuroradiological examination euro 245 per patient. Overall treatment costs were euro 319 per patient. We calculated an overall loss of euro 476,752 or euro 109.19 per patient. Outpatients caused a total loss of euro 456,665.83 or euro 211 per patient, consults a total loss of euro 161 683.16 or euro 261.20 per patient, daycare patients a slight profit of euro 30,370 or euro 40 per patient and inpatients a total profit of euro 111,225 or euro 135 per day.

CONCLUSION

Managerial optimization can yield considerable cost reductions in the G-DRG coding system, without any change in treatment strategies, selection of profitable patients or dismissal of personnel. Inversely, additional personnel are needed to accomplish the implementation process. Board certification was unveiled to constitute the key structural implementation that ensures the economic survival of the department and continuing medical excellence for the patients.

[A rare case of cannabis arteritis]

A 24-year old woman, heavy cannabis smoker with progressive Raynauld's phenomenon and digital necrosis is presented. Systemic sclerosis and other connective tissue disorders as well as arteriosclerosis and arterial emboli were excluded with appropriate laboratory examinations. Arteriography revealed multiple forearm, palmar and digital occlusions with corkscrew-shaped vessels. Based on these characteristic arteriography and clinical findings, the diagnosis of cannabis-arteritis was finally retained. With careful necrectomy, conservative wound dressings and secondary prostacyclin therapy a complete healing of digital necrosis was observed. There was no recurrence during the 6 month-follow-up. This observation demonstrates that cannabis may represent a possible cofactor in the pathogenesis of arteritis in young smokers. Early recognition is important to avoid irreversible complications such as loss of digits.

Generation of oxoiron (IV) tetramesitylporphyrin pi-cation radical complexes by m-CPBA oxidation of ferric tetramesitylporphyrin derivatives in butyronitrile at - 78 degrees C. Evidence for the formation of six-coordinate oxoiron (IV) tetramesitylporphyrin pi-cation radical complexes FeIV = O(tmp*)X (X = Cl-, Br-), by Mössbauer and X-ray absorption spectroscopy

The generation of six-coordinate oxoiron (IV) tetramesitylporphyrin pi-caption radical complexes by m-CPBA (meta-chloroperbenzoic acid) oxidation of ferric tetramesitylporphyrin derivatives in butyronitrile at - 78 degrees C was investigated. UV-Vis and EPR spectroscopies indicate that the axial ligand present in the ferric starting derivatives is retained in the high-valent iron complexes. Indirect evidence for the formation of six-coordinate oxoiron (IV) tetramesitylporphyrin complexes FeIV = O(tmp*)X (X=Cl-, Br-) by m-CPBA oxidation of FeX(tmp) (X=Cl-, Br-) in butyronitrile at - 78 degrees C was also obtained by Mössbauer spectroscopy. Direct confirmation of the presence of a halide ion as second axial ligand of iron in these high-valent iron species was obtained by X-ray absorption spectroscopy. The EXAFS spectra of the samples obtained by m-CPBA oxidation of FeX(tmp) (X=Cl-, Br-) were refined using two different coordination models including both four porphyrinato-nitrogens and the axial oxo group. The two models include (model I) or exclude (model II) the axial halogen. The statistical tests indicate the presence of a halide ion as second axial ligand of iron in both derivatives. The refinements led to the following bond distances: FeIV=O(tmp*)Cl(3):Fe-O=1.66(1),Fe-Cl=2.39(2) and Fe-Np=1.99(1) A;FeIV=O(tmp*)Br(4):Fe-O=1.65(1),Fe-Br=2.93(2), Fe-Np=2.02(1) A. The lengthening of the Fe-X(X=Cl-, Br-) distances relative to those occurring in the ferric precursor porphyrins is, most probably, related to the strong trans influence of the oxoiron(IV) fragment present in 3 or 4.

Brain imaging in a patient with hemimicropsia

Hemimicropsia is an isolated misperception of the size of objects in one hemifield (objects appear smaller) which is, as a phenomenon of central origin, very infrequently reported in literature. We present a case of hemimicropsia as a selective deficit of size and distance perception in the left hemifield without hemianopsia caused by a cavernous angioma with hemorrhage in the right occipitotemporal area. The symptom occurred only intermittently and was considered the consequence of a local irritation by the hemorrhage. Imaging data including a volume-rendering MR data set of the patient's brain were transformed to the 3-D stereotactic grid system by Talairach and warped to a novel digital 3-D brain atlas. Imaging analysis included functional MRI (fMRI) to analyse the patient's visual cortex areas (mainly V5) in relation to the localization of the hemangioma to establish physiological landmarks with respect to visual stimulation. The lesion was localized in the peripheral visual association cortex, Brodmann area (BA) 19, adjacent to BA 37, both of which are part of the occipitotemporal visual pathway. Additional psychophysical measurements revealed an elevated threshold for perceiving coherent motion, which we relate to a partial loss of function in V5, a region adjacent to the cavernoma. In our study, we localized for the first time a cerebral lesion causing micropsia by digital mapping in Talairach space using a 3-D brain atlas and topologically related it to fMRI data for visual motion. The localization of the brain lesion affecting BA 19 and the occipitotemporal visual pathway is discussed with respect to experimental and case report findings about the neural basis of object size perception.