Evolutionary analysis of SARS-CoV-2 spike protein for its different clades

The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) has become the main target for antiviral and vaccine development. Despite its relevance, e information is scarse about its evolutionary traces. The aim of this study was to investigate the diversification patterns of the spike for each clade of SARS‐CoV‐2 through different approaches. Two thousand and one hundred sequences representing the seven clades of the SARS‐CoV‐2 were included. Patterns of genetic diversifications and nucleotide evolutionary rate were estimated for the spike genomic region. The haplotype networks showed a star shape, where multiple haplotypes with few nucleotide differences diverge from a common ancestor. Four hundred seventy‐nine different haplotypes were defined in the seven analyzed clades. The main haplotype, named Hap‐1, was the most frequent for clades G (54%), GH (54%), and GR (56%) and a different haplotype (named Hap‐252) was the most important for clades L (63.3%), O (39.7%), S (51.7%), and V (70%). The evolutionary rate for the spike protein was estimated as 1.08 × 10⁻³ nucleotide substitutions/site/year. Moreover, the nucleotide evolutionary rate after nine months of the pandemic was similar for each clade. In conclusion, the present evolutionary analysis is relevant as the spike protein of SARS‐CoV‐2 is the target for most therapeutic candidates; besides, changes in this protein could have consequences on viral transmission, response to antivirals and efficacy of vaccines. Moreover, the evolutionary characterization of clades improves knowledge of SARS‐CoV‐2 and deserves to be assessed in more detail as re‐infection by different phylogenetic clades has been reported.

Seroprevalence of hepatitis B, hepatitis C and HIV infection among patients undergoing haemodialysis in Buenos Aires, Argentina

Introduction. Blood-borne infections are a major cause of harm in individuals on haemodialysis (HD). In particular, knowledge about hepatitis B (HBV), hepatitis C (HCV) and human immunodeficiency virus (HIV) status in HD patients is a major concern, since these infections may cause comorbidities in this setting. There is a paucity of data regarding this issue in Argentina.Hypothesis/Gap Statement. The epidemiological surveillance of HBV, HCV, and HIV is a fundamental tool for planning and implementing health strategies in order to prevent and control viral transmission of these viral agents.Aim. To determine the seroprevalence of HBV, HCV and HIV infections in HD patients in Buenos Aires, Argentina.Methodology. Seven hundred and forty-eight HD patients were included in a retrospective cross-sectional study. Serological assays were performed to determine HBV, HCV and HIV status. HBV HBsAg and anti-HBc IgG were analysed using AxSYM (samples before 2010) or the Architect Abbott system (samples since 2010), anti-HCV IgG testing was performed using the anti-HCV enzyme immunoassay AxSYM HCV V3.0 and ARCHITECT anti-HCV, while HIV was tested for using AxSYM HIV 1/2 gO and ARCHITECT HIV Ag/Ab Combination. HCV genotyping was carried out by phylogenetic analysis of the NS5B partial gene.Results. Infection with one of the viruses was detected in 31.1 % of patients [HBV in 82 (11.0 %), HCV in 179 (23.9 %) and HIV in 6 (0.8 %)]. Thirty-two (4.3 %) patients had 2 virus markers [27 (3.6 %) with HCV/HBV, 4 (0.5 %) with HCV/HIV and 1 (0.13 %) with HBV/HIV]. Finally, a single patient (0.13 %) presented all three markers. Time on dialysis was correlated with HCV but not with HBV infection. The HCV subtype distribution in HD patients was inverted with respect to that observed in the general population (HCV-1a 73.2 % and HCV-1b 26.8 % in HD vs HCV-1a 26.5 % and HCV-1b 73.5 % in the general population, P <0.001).Conclusion. Despite the implementation of universal precautionary biosafety standards for dialysis, infection with HBV and HCV continues to occur at very high rates in HD patients. The results emphasize the need to carry out proactive tasks for early diagnosis and treatment of infected individuals and to vaccinate those with non-protective antiHBs antibodies in order to reduce morbidity and mortality in HD patients.

Phylogenetic analysis of SARS-CoV-2 in the first few months since its emergence

During the first few months of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) evolution in a new host, contrasting hypotheses have been proposed about the way the virus has evolved and diversified worldwide. The aim of this study was to perform a comprehensive evolutionary analysis to describe the human outbreak and the evolutionary rate of different genomic regions of SARS-CoV-2. The molecular evolution in nine genomic regions of SARS-CoV-2 was analyzed using three different approaches: phylogenetic signal assessment, emergence of amino acid substitutions, and Bayesian evolutionary rate estimation in eight successive fortnights since the virus emergence. All observed phylogenetic signals were very low and tree topologies were in agreement with those signals. However, after 4 months of evolution, it was possible to identify regions revealing an incipient viral lineage formation, despite the low phylogenetic signal since fortnight 3. Finally, the SARS-CoV-2 evolutionary rate for regions nsp3 and S, the ones presenting greater variability, was estimated as 1.37 × 10^-3 and 2.19 × 10^-3 substitution/site/year, respectively. In conclusion, results from this study about the variable diversity of crucial viral regions and determination of the evolutionary rate are consequently decisive to understand essential features of viral emergence. In turn, findings may allow the first-time characterization of the evolutionary rate of S protein, crucial for vaccine development.

The transcaruncular approach in repair of orbital fractures: a retrospective study

The use of a transcaruncular approach to the medial orbit provides excellent exposure of the medial wall and avoids a cutaneous scar. This article presents the clinical procedure in a retrospective study of 8 patients. An incision through the caruncle, combined with an incision along the inferior conjunctival fornix, provides wide exposure of the medial and inferior orbit. Traumatic fractures of the orbit typically involve the thin bone of the medial and inferior walls. The clinical history and findings in 8 patients with bony orbital fractures are presented. In each case, surgical repair was based on the transcaruncular approach. Results of postoperative evaluation (range of 24 days to 32.5 months) are described, with a mean follow-up period of 8.5 months. The authors conclude that the transcaruncular approach is well suited to surgical repair of blow-out fractures to the medial orbit, in combination with an inferior transconjunctival incision.

Criteria for nonsurgical management of subperiosteal abscess of the orbit: analysis of outcomes 1988-1998

PURPOSE

On the basis of bacteriologic studies, we have recommended expectant observation with intravenous antibiotics for subperiosteal abscess (SPA) of the orbit in patients less than 9 years of age, given the absence of eight other specific surgical criteria. We attempted to test these recommendations with a prospective study.

STUDY DESIGN

Prospective noncomparative case series.

PARTICIPANTS

Forty patients younger than 9 years of age treated for orbital SPAs at the Childrens Hospital of Wisconsin from 1988 to 1998.

METHODS

Specific management criteria were applied to a cohort of 37 orbital SPA patients. Three other orbital SPA patients under the age of 9, either ineligible for medical therapy or treated outside our guidelines, were also studied. Clinical data for all patients were reviewed and analyzed.

MAIN OUTCOME MEASURES

Clinical resolution of the abscess, as evidenced by normal visual acuity, pupillary examination, motility, and globe position on the affected side.

RESULTS

Eight patients met criteria for surgical treatment and underwent prompt drainage. Of the 29 patients for whom initial nonsurgical management was recommended, 27 (93.1%) SPAs cleared with expectant observation on intravenous antibiotics, and 2 patients defaulted to surgical intervention. All cases had successful clinical outcomes.

CONCLUSIONS

In patients less than 9 years of age, orbital SPAs are likely to resolve without surgery, provided certain surgical criteria are absent.

Correlation of preoperative computed tomography and postoperative ocular motility in orbital blowout fractures

PURPOSE

To determine a relationship between preoperative soft tissue disruption and postoperative ocular motility in orbital blowout fractures.

METHODS

This retrospective cohort study reviewed 30 patients who met all criteria: retrievable coronal computed tomography (CT) scans; internal fractures of the orbital floor, with or without medial wall extension; preoperative diplopia; repair by a single surgeon; complete release of entrapped tissues; and postoperative binocular visual fields (BVFs). Motility outcomes were quantified by one group of the authors, who measured the vertical fusion within BVFs. Other authors analyzed CT scans, designating each fracture as either A or B, based on lesser or greater soft tissue distortion relative to the configuration of bone fragments. The interval between trauma and surgery was also determined.

RESULTS

Among the 15 patients with a postoperative motility outcome poorer than the median (86 degrees or less), four (27%) had A fractures; 11 (73%) had B fractures. Among the 15 patients with an outcome better than the median (88 degrees or more), 10 (67%) had A fractures; five (33%) had B fractures. Differences were more defined away from the median. Among five patients with B fractures and better than the median result, three (60%) had surgical repair during the first week after injury. Among the 11 patients with B fractures and less than the median result, one (9%) had repair during the first week.

CONCLUSIONS

Postoperative motility is influenced by soft tissue-bone fragment relationships. Whether the outcome can be altered by earlier surgery in selected cases will be determined by prospective studies.

Periocular deep cutaneous basal cell carcinoma

PURPOSE

The distinction between benign and malignant cutaneous periocular lesions can be difficult, as the clinical history and appearance are often quite similar. When present, typical cutaneous changes are often helpful in distinguishing between benign and malignant neoplasms. However, when tumors lack characteristic epidermal change, histopathologic examination may be necessary to confirm the diagnosis. The authors present their experience in the evaluation and management of two patients with periocular basal cell carcinoma who were initially diagnosed as having benign cysts.

METHODS

The case records for two patients with periocular basal cell carcinoma were reviewed. Preoperative and postoperative photographs were available for comparison in one case. For each patient, the medical history, clinical presentation, histology, and surgical outcome were reviewed.

RESULTS

In each case, the periocular mass was initially diagnosed as a benign process. Histopathologic examination following excisional biopsy established the diagnosis of basal cell carcinoma in both patients. Following biopsy, residual tumor was removed by the Mohs micrographic technique. There were no surgical complications and no tumor recurrences during follow-up of one year and eight years.

CONCLUSIONS

Periocular basal cell carcinoma may mimic benign cystic lesions of the central face. Incorrect diagnosis may result in delayed or inappropriate therapy, or failure to submit seemingly benign lesions for histopathologic examination. Definitive treatment requires complete excision with histologic margin control.

Acute dacryocystitis as a presenting sign of pediatric leukemia

PURPOSE

To report acute dacryocystitis with preseptal cellulitis as the presenting sign of leukemia in a child.

METHODS

Case report and literature review.

RESULTS

During the initial evaluation of a 17-month-old child with epiphora, left lower eyelid swelling, and a tender left medial canthal mass, a complete blood cell count demonstrated pancytopenia. Bone marrow biopsy disclosed replacement of normal cellular architecture with a dense infiltrate of leukocyte blast forms. DNA analysis disclosed a translocation between chromosome 10 and 11, consistent with the diagnosis of nonlymphocytic leukemia. Although the adjacent lower eyelid cellulitis responded to intravenous antibiotics, lacrimal sac distention decreased only after chemotherapy was initiated.

CONCLUSIONS

Dacryocystitis with preseptal cellulitis can be a presenting sign of leukemia. This blood malignancy should be considered in patients whose leukocyte counts do not correlate with their clinical presentation.

Deep transorbital approach to the apex and cavernous sinus

Tumors of the orbital apex are difficult to approach through a standard lateral orbitotomy exposure. The transcranial approach has been described, but it requires an open craniotomy as well as dissection through the annulus of Zinn in its tight superior segment to reach intraconal and inferior lateral tumors. It is well recognized that the transcranial approach is optimal only for tumors of the superomedial orbital apex. Our study demonstrates that by enlarging the bony incision of a classic lateral orbitotomy to include a generous marginotomy and removing the deep sphenoid wing up to the superior orbital fissure, good exposure of the lateral orbital apex can be obtained. Tumors of the apex, including those that extend slightly into the cavernous sinus, can be removed from the cranial nerves and extraocular muscle origins in en face fashion, providing optimal ability to identify the delicate neurovascular structures of the orbital apex and avoid damage to them. The operating microscope is extremely useful for bony and soft tissue dissection. We report four benign tumors of the orbital apex removed using this approach. Two tumors encroached slightly into the cavernous sinus. Three of four patients were told that they had inoperable tumors. By use of the deep orbital apex approach described, all four tumors were successfully exposed and removed. Visual and motor function was unchanged or improved in all four patients, with the exception of one tumor that incorporated the inferior division of the third cranial nerve; in that patient, the transected nerve was anastomosed microscopically, and partial return of function was noted. The transorbital ophthalmic approach to tumors of the inferolateral orbital apex has significant potential advantages in comparison with a frontal craniotomy approach.

Carcinoma of the male breast metastatic to both orbits

We report the case of a 43-year-old man who presented with painless proptosis of the right eye of 6 weeks' duration. Examination demonstrated a tense right orbit and decreased vision and extraocular motility bilaterally. Diagnostic evaluation included computed tomographic imaging of the head and orbits, a therapeutic trial of high-dose systemic corticosteroids, and orbital biopsy, which revealed the presence of metastatic adenocarcinoma. The primary tumor was found to be an estrogen-receptor-positive, infiltrating ductal adenocarcinoma of the right breast. Therapy included lumpectomy of the breast mass, orbital irradiation, and hormonal therapy. Metastatic carcinoma of the breast should be considered in the differential diagnosis of orbital neoplastic disease in the male patient.

Orbital blow-out fractures: correlation of preoperative computed tomography and postoperative ocular motility

BACKGROUND/PURPOSE

Although the management of orbital blow-out fractures was controversial for many years, refined imaging with computed tomography (CT) helped to narrow the poles of the debate. Many orbital surgeons currently recommend repair if fracture size portends late enophthalmos, or if diplopia has not substantially resolved within 2 weeks of the injury. While volumetric considerations have been generally well-served by this approach, ocular motility outcomes have been less than ideal. In one series, almost 50% of patients had residual diplopia 6 months after surgery. A fine network of fibrous septa that functionally unites the periosteum of the orbital floor, the inferior fibrofatty tissues, and the sheaths of the inferior rectus and oblique muscles was demonstrated by Koornneef. Entrapment between bone fragments of any of the components of this anatomic unit can limit ocular motility. Based on the pathogenesis of blow-out fractures, in which the fibrofatty-muscular complex is driven to varying degrees between bone fragments, some measure of soft tissue damage might be anticipated. Subsequent intrinsic fibrosis and contraction can tether globe movement, despite complete reduction of herniated orbital tissue from the fracture site. We postulated that the extent of this soft tissue damage might be estimated from preoperative imaging studies.

METHODS

Study criteria included: retrievable coronal CT scans; fractures of the orbital floor without rim involvement, with or without extension into the medial wall; preoperative diplopia; surgical repair by a single surgeon; complete release of entrapped tissues; and postoperative ocular motility outcomes documented with binocular visual fields (BVFs). Thirty patients met all criteria. The CT scans and BVFs were assessed by different examiners among the authors. Fractures were classified into 3 general categories and 2 subtypes to reflect the severity of soft tissue damage within each category. "Trap-door" injuries, in which bone fragments appeared to have almost perfectly realigned, were classified as type I fractures. In the I-A subtype, no orbital tissue was visible on the sinus side of the fracture line. In the I-B subtype, soft tissue with the radiodensity of orbital fat was visible within the maxillary sinus. In type II fractures, bone fragments were distracted and soft tissue was displaced between them. In the II-A subtype, soft tissue displacement was less than, or proportional to, bone fragment distraction. In the II-B subtype, soft tissue displacement was greater than bone fragment distraction. In type III fractures, displaced bone fragments surrounded displaced soft tissue in all areas. In the III-A subtype, soft tissue and bone were moderately displaced. In the III-B subtype, both were markedly displaced. Motility outcomes were quantified by measuring the vertical excursion in BVFs. The interval between trauma and surgical repair was also determined.

RESULTS

Among the 15 patients with a motility outcome in BVFs which was poorer than the median (86 degrees or less of single binocular vertical excursion), 4 patients (27%) had type A fractures; 11 patients (73%) had type B fractures. Among the 15 patients with a better outcome than the median (88 degrees or more), 10 patients (67%) had type A fractures; 5 patients (33%) had type B fractures. These differences became more defined as analysis moved away from the median. Among 5 patients with type B fractures and better than the median result in BVFs, 3 patients (60%) had surgical repair during the first week after injury. Among the 11 patients with type B fractures and less than the median result, 1 patient (9%) had repair during the first week.

CONCLUSIONS

When the CT-depicted relationship between bone fragments and soft tissues is considered, a wide spectrum of injuries is subsumed under the rubric of blow-out fractures. In general, greater degrees of soft tissue incarceration or displacement, with presumably greater intrinsic damage and subsequent fibrosis, appear to result in poorer motility outcomes. Although this retrospective study does not conclusively prove its benefit, an urgent surgical approach to selected injuries should be considered.

Combined embolization and surgical treatment of arteriovenous malformation of the orbit

We examined three patients with arteriovenous malformation of the orbit. At initial examination, all patients had a slowly progressive mass effect combined with congestive symptoms and clinical signs typical of an orbital vascular lesion. Arteriovenous malformation of the orbit was diagnosed on the basis of clinical and radiographic assessment, including the use of digital subtraction angiography and in one patient, magnetic resonance imaging. Treatment of each patient involved neuroradiologic embolization of the vascular lesion followed by surgical excision. Transient complications of endovascular management occurred. In one patient particulate emboli migrated into the central retinal artery after postembolization orbital surgical excision; consequent focal ischemic retinopathy contributed to short-term visual field deficits, which eventually resolved spontaneously. In another patient, spasm of the ophthalmic artery occurred during embolization, resulting in a transient afferent pupillary defect and loss in visual acuity to 20/60, which resolved over the subsequent week. High-flow orbital vascular lesions represent a considerable treatment challenge because of the complex anatomic and hemorrhagic characteristics of the malformation. Neuroradiologic characterization and embolization as a preoperative adjuvant is not without risk but offers an important advantage in the treatment of these formidable lesions. A combination of endovascular and surgical management may allow otherwise inoperable lesions to be treated successfully.

Mycotic keratitis by Drechslera spicifera

The Drechslera state of Cochiobolus spicifer, Nelson 1964, was isolated from a case of keratomycosis. The patient, a 19 year old man, showed a large corneal ulcer with hypopyon associated with the introduction of dust. The direct examination of several scrapings revealed dark-brown hyphae. This species has been reported as a casual agent of a nodular granulomatous mass in the foot of a cat and in the skin of a horse.