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Microbial Cell (Graz, Austria) Oct 2022Holins are generally believed to generate large membrane lesions that permit the passage of endolysins across the cytoplasmic membrane of prokaryotes, ultimately... (Review)
Review
Holins are generally believed to generate large membrane lesions that permit the passage of endolysins across the cytoplasmic membrane of prokaryotes, ultimately resulting in cell wall degradation and cell lysis. However, there are more and more examples known for non-lytic holin-dependent secretion of proteins by bacteria, indicating that holins somehow can transport proteins without causing large membrane lesions. Phage-derived holins can be used for a non-lytic endolysin translocation to permeabilize the cell wall for the passage of secreted proteins. In addition, clostridia, which do not possess the Tat pathway for transport of folded proteins, most likely employ non-lytic holin-mediated transport also for secretion of toxins and bacteriocins that are incompatible with the general Sec pathway. The mechanism for non-lytic holin-mediated transport is unknown, but the recent finding that the small holin TpeE mediates a non-lytic toxin secretion in opened new perspectives. TpeE contains only one short transmembrane helix that is followed by an amphipathic helix, which is reminiscent of TatA, the membrane-permeabilizing component of the Tat translocon for folded proteins. Here we review the known cases of non-lytic holin-mediated transport and then focus on the structural and functional comparison of TatA and TpeE, resulting in a mechanistic model for holin-mediated transport. This model is strongly supported by a so far not recognized naturally occurring holin-endolysin fusion protein.
PubMed: 36262927
DOI: 10.15698/mic2022.10.785 -
Insights Into Imaging Oct 2018Calvarial lesions are often asymptomatic and are usually discovered incidentally during computed tomography or magnetic resonance imaging of the brain. Calvarial lesions... (Review)
Review
Calvarial lesions are often asymptomatic and are usually discovered incidentally during computed tomography or magnetic resonance imaging of the brain. Calvarial lesions can be benign or malignant. Although the majority of skull lesions are benign, it is important to be familiar with their imaging characteristics and to recognise those with malignant features where more aggressive management is needed. Clinical information such as the age of the patient, as well as the patient's history is fundamental in making the correct diagnosis. In this article, we will review the imaging features of both common and uncommon calvarial lesions, as well as mimics of these lesions found in clinical practice. TEACHING POINTS: • Skull lesions are usually discovered incidentally; they can be benign or malignant. • Metastases are the most frequent cause of skull lesions. • Metastatic lesions are most commonly due to breast cancer in adults and neuroblastoma in children. • Multiple myeloma presents as the classic "punched out" lytic lesions on radiographs. • Eosinophilic granuloma is an osteolytic lesion with bevelled edges.
PubMed: 30232767
DOI: 10.1007/s13244-018-0643-0 -
Journal of Neurological Surgery Reports Jul 2022Cranial dermoids have the tendency to occur in the midline, especially near fontanelles and sutures early in the life of a patient. Here we present an unusual case of an...
Cranial dermoids have the tendency to occur in the midline, especially near fontanelles and sutures early in the life of a patient. Here we present an unusual case of an intraosseous dermoid that presented initially as a lytic lesion, off of the midline and not associated with cranial sutures or fontanelles. The diameter of the lesion grew to approx 15 mm over time, thus the decision was made to take the child to surgery for removal of dermoid with the use of neuronavigation and cranioplasty. A dermoid cyst was confirmed on histopathologic analysis.
PubMed: 35832686
DOI: 10.1055/s-0042-1750291 -
Current Health Sciences Journal 2021A 40-year-old African American male with long standing headaches and unintentional weight loss presented with nausea, vomiting, and blurry vision. Laboratory findings...
A 40-year-old African American male with long standing headaches and unintentional weight loss presented with nausea, vomiting, and blurry vision. Laboratory findings include hyponatremia and mildly raised liver enzymes. He underwent cholecystectomy six months prior for unexplained nausea and vomiting, which in hindsight was likely neurologic-induced vomiting from neurosarcoidosis. Brain imaging revealed diffuse, leptomeningeal, nodular enhancement involving the brain, brainstem, and upper cervical spinal cord. Further work up showed extensive lymphadenopathy above and below the diaphragm, solitary liver lesion, and multiple lytic lesions involving bones. Iliac spine biopsy revealed ill-defined, non-caseating granulomas with giant cell reaction infiltrating bone fragments. Acid-fast bacilli and fungal stains were negative. Patient was treated with steroids. Diagnosis of neurosarcoidosis is challenging in the absence of physical signs and symptoms. However, radiological and pathological correlation in clinical suspicion of sarcoidosis is helpful in more accurate diagnosis and timely management of the patient.
PubMed: 34211757
DOI: 10.12865/CHSJ.47.01.18 -
Insights Into Imaging Oct 2018Lytic lesions of the skull include a wide range of diseases, ranging from benign conditions such as arachnoid granulations or vascular lacunae, to aggressive malignant... (Review)
Review
Lytic lesions of the skull include a wide range of diseases, ranging from benign conditions such as arachnoid granulations or vascular lacunae, to aggressive malignant lesions such as lymphomas or metastases. An early and correct characterisation of the nature of the lesion is, therefore, crucial, in order to achieve a fast and appropriate treatment option. In this review, we present the radiological appearance of the most frequent lytic lesions of the skull, describing findings from different imaging modalities (plain X-rays, CT and MRI), with particular attention to diagnostic clues and differential diagnoses. TEACHING POINTS: • Osteolytic skull lesions may be challenging to diagnose. • Association of different imaging techniques may aid image interpretation. • Clinical information and extensive knowledge of possible differential diagnoses is essential. • Some osteolytic tumours, although benign, may present as locally aggressive lesions. • Malignant lesions require accurate staging, followed by variable treatment approaches.
PubMed: 30232766
DOI: 10.1007/s13244-018-0653-y -
Cureus Aug 2021Lipomas are benign lesions of adipose tissue, which commonly affect the soft tissues but are rarely found in the musculoskeletal system. Intraosseous lipomas are rare...
Lipomas are benign lesions of adipose tissue, which commonly affect the soft tissues but are rarely found in the musculoskeletal system. Intraosseous lipomas are rare benign tumors and even rarer in calcaneum, only to be found incidentally in the majority of cases. We report a case of a 45-year-old male patient who presented to the outpatient department with complaints of bilateral heel pain, which was initially treated conservatively as the presentation was similar to plantar fasciitis. On further follow-up, a plain radiograph of the ankles was taken, which showed a lytic lesion of the calcaneum with mild sclerotic margins on the right side with normal left foot radiographs. On magnetic resonance imaging, the lytic lesion demonstrated hyperintense signals on T1-weighted sagittal images, characteristic of fatty tissue, which helped us in arriving at the diagnosis of an intraosseous lipoma. The patient was treated by conservative means with physiotherapy, which relieved the pain, and on serial follow-ups, the lesion was found non-progressive on successive radiological evaluation. The differential diagnosis of such an entity includes plantar fasciitis, tumors such as an aneurysmal bone cyst, bone infarct, etc. With the increasing use of magnetic resonance imaging and computed tomography scans, physicians should be aware of the possibility of an intraosseous lipoma of the calcaneum, which should be ruled out during evaluation. Although possible, malignant pathology or aggressive transformation of such lesions is very rare; however, the lesion should be evaluated adequately and managed by surgical means in cases non-responsive to various conservative modalities.
PubMed: 34513500
DOI: 10.7759/cureus.16929 -
Brain : a Journal of Neurology May 2022Neuromyelitis optica is an autoimmune inflammatory disorder targeting aquaporin-4 water channels in CNS astrocytes. Histopathological descriptions of astrocytic lesions...
Neuromyelitis optica is an autoimmune inflammatory disorder targeting aquaporin-4 water channels in CNS astrocytes. Histopathological descriptions of astrocytic lesions reported in neuromyelitis optica so far have emphasized a characteristic loss of aquaporin-4, with deposition of IgG and complement and lysis of astrocytes, but sublytic reactions have been underappreciated. We performed a multi-modality study of 23 neuromyelitis optica autopsy cases (clinically and/or pathologically confirmed; 337 tissue blocks). By evaluating astrocytic morphology, immunohistochemistry and AQP4 RNA transcripts, and their associations with demyelinating activity, we documented a spectrum of astrocytopathy in addition to complement deposition, microglial reaction, granulocyte infiltration and regenerating activity. Within advanced demyelinating lesions, and in periplaque areas, there was remarkable hypertrophic astrogliosis, more subtle than astrocytic lysis. A degenerative component was suggested by 'dystrophic' morphology, cytoplasmic vacuolation, Rosenthal fibres and associated stress protein markers. The abundance of AQP4 mRNA transcripts in sublytic reactive astrocytes devoid of aquaporin-4 protein supported in vivo restoration following IgG-induced aquaporin-4 endocytosis/degradation. Astrocytic alterations extending beyond demyelinating lesions speak to astrocytopathy being an early and primary event in the evolving neuromyelitis optica lesion. Focal astrocytopathy observed without aquaporin-4 loss or lytic complement component deposition verifies that astrocytic reactions in neuromyelitis optica are not solely dependent on IgG-mediated aquaporin-4 loss or lysis by complement or by IgG-dependent leucocyte mediators. We conclude that neuromyelitis optica reflects a global astrocytopathy, initiated by binding of IgG to aquaporin-4 and not simply definable by demyelination and astrocytic lysis. The spectrum of astrocytic morphological changes in neuromyelitis optica attests to the complexity of factors influencing the range of astrocytic physiological responses to a targeted attack by aquaporin-4-specific IgG. Sublytic astrocytic reactions are no doubt an important determinant of the lesion's evolution and potential for repair. Pharmacological manipulation of the astrocytic stress response may offer new avenues for therapeutic intervention.
Topics: Aquaporin 4; Astrocytes; Humans; Immunoglobulin G; Neuromyelitis Optica
PubMed: 34718426
DOI: 10.1093/brain/awab394 -
Italian Journal of Pediatrics Feb 2018Chronic recurrent multifocal osteomyelitis (CRMO), also known as chronic nonbacterial osteomyelitis, is a rare, noninfectious inflammatory disorder that causes... (Review)
Review
BACKGROUND
Chronic recurrent multifocal osteomyelitis (CRMO), also known as chronic nonbacterial osteomyelitis, is a rare, noninfectious inflammatory disorder that causes multifocal bone lesions with swelling and pain. Lytic and sclerotic bone lesions could be found on X-ray. Short tau inversion recovery magnetic resonance imaging (STIR MRI) shows bone marrow oedema, bone expansion, lytic areas and periosteal reaction. CRMO is characterized by periodic exacerbations and remissions of unclear/unknown pathogenesis.
CASE PRESENTATION
A 10 years old girl, suffering from pain in her right shoulder since the age of 9 years presented to our Department. Thanks to clinical data, laboratoristic and radiological findings and bone biopsy CRMO was diagnosed. So patient started anti-inflammatory treatment and her conditions improved.
CONCLUSIONS
In a child with bone pain should be considered also rare condition as CRMO to perform a correct diagnosis and start an adequate treatment avoiding complications such as bone damage. This condition should be suspected in a child with recurrent bone pain, modest increase of inflammatory indices, lytic or sclerotic bone lesion on X Ray. Typical CRMO localizations are metaphyses of long bones, pelvis, clavicle, vertebral column, sternum, ribs, jaw, but any bone can be involved. The most common CRMO differential diagnosis is represented by infections, malignant bone tumors, Langerhans Cells Histiocytosis (LCH).
Topics: Adrenal Cortex Hormones; Blood Chemical Analysis; Child; Diagnosis, Differential; Female; Follow-Up Studies; Humans; Magnetic Resonance Imaging; Osteomyelitis; Pain Measurement; Radiography; Severity of Illness Index; Shoulder Pain; Treatment Outcome
PubMed: 29454377
DOI: 10.1186/s13052-018-0463-3 -
International Journal of Surgery Case... May 2022Giant cell granulomas (GCG) and ossifying fibroma (OF) of the jaw are benign reactive lesions. GCG characterized by the presence of abundant multinucleated giant cells...
INTRODUCTION AND IMPORTANCE
Giant cell granulomas (GCG) and ossifying fibroma (OF) of the jaw are benign reactive lesions. GCG characterized by the presence of abundant multinucleated giant cells in a cellular stroma. On the other hand, the characteristic feature of OF is benign connective tissue replaces the normal bone. Combination of these two lesions, GCG with OF, in the jaw is extremely rare.
CASE PRESENTATION
A 35-year-old woman presented with complains of right jaw swelling with no history of previous disease or lesion and no family history of such lesions. By physical examination, a painful swelling in the right jaw was observed. A computed tomography scan of the facial bone showed a large, expansible, lytic lesion with narrow zone of transition and internal septations, involving the right side of the maxilla and floor of the right maxillary sinus. Histopathologic examination revealed a lesion with combined features of OF and GCG.
CLINICAL DISCUSSION
GCG and OF are two of the most frequent oral lesions. Presence of both tumors in one patient as a combined lesion is highly unusual, with only a few reported cases in the literature. On clinical and radiologic examination, diagnosing such a combined lesion is not possible, however, such lesions can be easily diagnosed by microscopic examination, indicating the importance of pathologic examination.
CONCLUSION
Occurrence of combined OF and GCG is a rare event. Proper histopathologic evaluation can contribute to accurate diagnosis and better management of such lesions. Confirmative diagnosis of such lesions by radiology alone is not possible.
PubMed: 35439729
DOI: 10.1016/j.ijscr.2022.107082 -
Ochsner Journal 2020Cholangiocarcinoma (CCC), a rare tumor arising from the viscera, has a poor prognosis. Although CCC is prone to metastasis, spread to the cranium and spine is...
Cholangiocarcinoma (CCC), a rare tumor arising from the viscera, has a poor prognosis. Although CCC is prone to metastasis, spread to the cranium and spine is exceedingly rare. Treatment for metastatic disease is palliative, with total resection of the primary lesion the only cure. We describe a case of metastatic CCC to the spine and cranium treated with surgical resection. A 61-year-old male with a history of hepatitis C with liver transplant and incidental discovery of CCC presented with gradually increasing back pain. Physical examination revealed a palpable nontender mass in the parieto-occipital area. Computed tomography survey of the spine and head revealed mixed sclerotic and lytic lesions of the T9, T11, L2, and L5 vertebral bodies, a lytic lesion on the T6 vertebral body, and a 1.4-cm lesion in the right occipital calvarium. The patient underwent right occipital craniotomy for excisional biopsy of the calvarial mass with gross total resection and immunohistochemical confirmation of CCC. The patient was started on gemcitabine chemotherapy and radiation therapy for spinal metastases. Three months later, the patient died from metastatic disease complications. To our knowledge, only 6 cases of cranial CCC have been reported, and only 2 reported mixed cranial/spinal involvement. We report a rare case of CCC metastasis to the spine and cranium that was treated with surgery, chemotherapy, and radiotherapy. CCC should be considered an exceedingly rare etiology with treatment options aimed solely at palliation. This case supplements the existing literature to inform medical and surgical decision-making.
PubMed: 32612476
DOI: 10.31486/toj.18.0142