Association of Panton Valentine Leukocidin (PVL) genes with methicillin resistant Staphylococcus aureus (MRSA) in Western Nepal: a matter of concern for community infections (a hospital based prospective study).

BACKGROUND: Methicillin resistant Staphylococcus aureus (MRSA) is a major human pathogen associated with nosocomial and community infections. Panton Valentine leukocidin (PVL) is considered one of the important virulence factors of S. aureus responsible for destruction of white blood cells, necrosis and apoptosis and as a marker of community acquired MRSA. This study was aimed to determine the prevalence of PVL genes among MRSA isolates and to check the reliability of PVL as marker of community acquired MRSA isolates from Western Nepal. METHODS: A total of 400 strains of S. aureus were collected from clinical specimens and various units (Operation Theater, Intensive Care Units) of the hospital and 139 of these had been confirmed as MRSA by previous study. Multiplex PCR was used to detect mecA and PVL genes. Clinical data as well as antimicrobial susceptibility data was analyzed and compared among PVL positive and negative MRSA isolates. RESULTS: Out of 139 MRSA isolates, 79 (56.8 %) were PVL positive. The majority of the community acquired MRSA (90.4 %) were PVL positive (Positive predictive value: 94.9 % and negative predictive value: 86.6 %), while PVL was detected only in 4 (7.1 %) hospital associated MRSA strains. None of the MRSA isolates from hospital environment was found positive for the PVL genes. The majority of the PVL positive strains (75.5 %) were isolated from pus samples. Antibiotic resistance among PVL negative MRSA isolates was found higher as compared to PVL positive MRSA. CONCLUSION: Our study showed high prevalence of PVL among community acquired MRSA isolates. Absence of PVL among MRSA isolates from hospital environment indicates its poor association with hospital acquired MRSA and therefore, PVL may be used a marker for community acquired MRSA. This is first study from Nepal, to test PVL among MRSA isolates from hospital environment.

Spinal tuberculosis, natural history of disease, classifications and principles of management with historical perspective.

PURPOSE: To describe the natural history spinal tuberculosis, classifications and principles of management based upon the grading of the neurological deficit. METHODS: Review of literature was conducted with the aim to provide the clinico-radiological correlation of the natural history of spinal tuberculosis in different stages. Management strategy is developed based upon the severity of the neurological deficit. RESULTS: A five stage natural history of spinal tuberculosis is described. Stage of neurological involvement is further divided into 4 grades, predominantly on the basis of progressively increasing motor deficits as negligible, mild, moderate and severe with sensory and autonomic dysfunctions. Suitable principles of management with role of rest, braces, chemotherapy and surgery are discussed. Neurological deficit grading based management is developed. Grade 1 and 2, conservative treatment, grade 3, gray zone and grade 4, operative treatment is emphasized. CONCLUSION: The five stages of natural history of tuberculosis of spine have been developed from the clinician's point of view. Management of tuberculosis of spine, in general, it is no different than management of soft tissue tuberculosis, in HIV negative or positive patients. Role of surgery is very limited. Management of tubercular paraplegia, based upon the grading of paraplegia is simple, logical, efficient and easy to understand and remember by any orthopedic surgeon.

The S1 subunits of SARS-CoV-2 variants differentially trigger the IL-6 signaling pathway in human brain endothelial cells and downstream impact on microglia activation.

Objectives: Cerebrovascular complications are prevalent in COVID-19 infection and post-COVID conditions; therefore, interactions of SARS-CoV-2 with cerebral microvascular cells became an emerging concern. Methods: We examined the inflammatory responses of human brain microvascular endothelial cells (HBMEC), the main structural element of the blood-brain barrier (BBB), following exposure to the S1 subunit of the spike protein of different SARS-CoV-2 variants. Specifically, we used the S1 subunit derived from the D614 variant of SARS-CoV-2, which started widely circulating in March of 2020, and from the Delta variant, which started widely circulating in early 2021. We then further examined the impact of the HBMEC secretome, produced in response to the S1 exposure, on microglial proinflammatory responses. Results: Treatment with S1 derived from the D614 variant and from the Delta variant resulted in differential alterations of the IL-6 signaling pathway. Moreover, the HBMEC secretome obtained after exposure to the S1 subunit of the D614 variant activated STAT3 in microglial cells, indicating that proinflammatory signals from endothelial cells can propagate to other cells of the neurovascular unit. Overall, these results indicate the potential for different SARS-CoV-2 variants to induce unique cellular signatures and warrant individualized treatment strategies. The findings from this study also bring further awareness to proinflammatory responses involving brain microvasculature in COVID-19 and demonstrate how the surrounding microglia react to each unique variant derived response.

Self-Assembled Amino Acid Microstructures as Biocompatible Physically Unclonable Functions (BPUFs) for Authentication of Therapeutically Relevant Hydrogels.

Counterfeited biomedical products result in significant economic losses and pose a public health hazard for over a million people yearly. Hydrogels, a class of biomedical products, are being investigated as alternatives to conventional biomedical products and are equally susceptible to counterfeiting. Here, a biocompatible, physically unclonable function (BPUF) to verify the authenticity of therapeutically relevant hydrogels are developed. The principle of BPUF relies on the self-assembly of tyrosine into fibril-like structures which are incorporated into therapeutically relevant hydrogels resulting in their random dispersion. This unclonable arrangement leads to distinctive optical micrographs captured using an optical microscope. These optical micrographs are transformed into a unique security code through cryptographic techniques which are then used to authenticate the hydrogel. The temporal stability of the BPUFs are demonstrated and additionally, exploit the dissolution propensity of the structures upon exposure to an adulterant to identify the tampering of the hydrogel. Finally, a platform to demonstrate the translational potential of this technology in validating and detecting tampering of therapeutically relevant hydrogels is developed. The potential of BPUFs to combat hydrogel counterfeiting is exemplified by its simplicity in production, ease of use, biocompatibility, and cost-effectiveness.

Assessment of Serum Elements Concentration and Polycystic Ovary Syndrome (PCOS): Systematic Review and Meta-analysis.

Change in the levels of trace elements has been linked with PCOS pathogenesis by various studies, whereas some had reported no such association. Therefore, in order to evaluate association of eleven trace element (Cu, Zn, Cr, Cd, Se, Mn, Fe, Mg, Co, Ni and Pb) serum concentration with PCOS pathogenesis, current systematic review and meta-analysis has been carried out. Literature search was conducted using PubMed, Central Cochrane Library, Google Scholar and Science Direct databases with appropriate keywords. Studies published upto 3rd of September were evaluated for eligibility with suitable inclusion and exclusion criteria. Only case-control studies examining the association of serum trace element concentrations between PCOS cases and controls were selected. Present meta-analysis identified 32 articles with 2317 PCOS and 1898 controls. The serum Cu (MD = 15.40; 95% CI = 4.32 to 26.48; p = 0.006), Co (MD = 0.01; 95% CI = 0.01 to 0.02; p = 0.000), Cr (MD = 0.04; 95% CI = 0.00 to 0.07; p = 0.03) and Fe (MD = 12.98; 95% CI = 5.87-20.09; p = 0.0003) concentration is significantly higher, while lower concentration has been observed for Se (MD = - 0.99; 95% CI = - 1.31 to - 0.67; p = 0.000) and Mg (MD = - 223.41; 95% CI = - 391.60 to - 55.23; p = 0.009) among women with PCOS in comparison with the healthy group. Concentration of other elements which were analysed is not significantly related to PCOS. In short, PCOS women has higher serum concentrations of Cu, Co, Cr and Fe and lower concentrations of Se and Mg. Studies with sub-population of obese, non-obese and with and without insulin resistance are important to understand the pathomechanism of these elements in the syndrome.

Settlement of [l8F]-FDG in the urinary bladder--a new sign.

PURPOSE: Settlement of fluorine-18 fluorodeoxyglucose ([18F]-FDG) in the urinary bladder is often noted in whole body PET/CT scan images with full urinary bladder but never received any careful attention. Purpose of this communication is to determine the clinical utility and application of this unreported phenomenon. METHODS: Four cases seen in the span of two years (2004 to 2006) exhibiting phenomenon of settlement of [18F]-FDG in the urinary bladder are being reported. One case with air in the urinary bladder is also reported to cover the differential diagnosis. RESULTS: All four patients showing this phenomenon had features of infection in the body/urine. CONCLUSION: Presence of this phenomenon demands careful evaluation of the urine by the clinician hence must be reported. This phenomenon can be confusing when there is air in the urinary bladder and this should be ruled out.

A novel approach of 67-Gallium-citrate three-phase bone scan to diagnose bone infection: A report of three cases.

OBJECTIVES: 67-Gallium-citrate three-phase bone scan (Ga-TPBS), a new approach for the diagnosis of bone infection is evaluated. The interpretation of TPBS is based on the normal physiological vascular endothelial-related response noted in infection. MATERIALS AND METHODS: Three cases of suspected bone infection as determined by clinical, laboratory, and radiological examinations were further subjected to conventional technetium-99m-TPBS (Tc-99m-TPBS) and Ga-TPBS. Nuclear scan diagnosis of bone infection was made by the presence of generalized vasodilatation with increased capillary permeability noted on the flow and the pool phase of the TPBS and the comparative evaluation of the 4 h delayed Tc-TPBS and 24-48 h delayed Ga-TPBS. Diagnosis of bone infection was confirmed in all three cases on histopathologcal examination of the surgically excised tissues. RESULTS: The data clearly indicated that all three cases of bone infection (osteomyelitis) had generalized massive flow and pool pattern. Infection could be diagnosed only on the Ga-TPBS by noting generalized vasodilatation with increased capillary permeability on the flow and the pool phase with focal retention of the radiotracer on the delayed scan. CONCLUSIONS: By incorporating the concept of vascular endothelial-related response causing massive vasodilatation in infection, the interpretation of the Ga-TPBS can be more précised as it is based on the normal physiology. In comparison to two Tc-99m scans (white blood cell scan + bone marrow scan), a single Ga-TPBS is also cost-effective and compliance friendly. Larger, comparative, and statistically unbiased studies are needed.

Three phase bone scan interpretation based upon vascular endothelial response.

OBJECTIVES: A new method of interpretation of Three Phase Bone Scan (TPBS) scan based upon the normal physiological vascular endothelial related response. MATERIALS AND METHODS: Fifty cases of TPBS were evaluated. Thirteen were normal. In remaining 37 positive studies, 20 showed localized hyperemic response. All localized hyperemic responses except one with vascular endothelial dysfunction were without infection (95.0%). Infection could be ruled out in absence of generalized massive flow and pool response. All 17 cases with generalized massive hyperemic response had infection, consistent with infection or CRPS/RSD. Micro-bacterial or histological confirmation of infection was obtained in 11 cases. All 11 cases with confirmed infection showed generalized massive hyperemic response (100.0%). Two were CRPS/RSD and 2 cases were of cellulitis (100.0%). Among remaining 2, one refused surgery and other was lost to follow-up. Additionally, 20 published cases in the literature of osteomyelitis were also analyzed. Nineteen cases of bone and joint infection, (osteomyelitis/arthritis/cellulitis) except one with endothelial dysfunction showed generalized massive increased flow and pool response (95.0%). All published cases of osteomyelitis in the literature showed generalized massive hyperemic response (100.0%). RESULTS: The data clearly indicated that 100% of the cases of bone infection (osteomyelitis/arthritis/cellulitis) and cases of CRPS/RSD showed generalized massive flow and pool pattern. Infection could be ruled out in absence of generalized massive flow and pool response. All 100% published cases of osteomyelitis in the literature showed positive vascular endothelial response. CONCLUSION: By incorporating the concept of vascular endothelial related response causing massive vasodilatation in infection, the interpretation of the TPBS can be more précised as it is based upon the normal physiology. Larger studies are recommended.

Incremental benefit of SPECT + CT bone scans over conventional planar and SPECT bone scans in vertebroplasty.

STUDY DESIGN: Planar bone scans with SPECT and SPECT + CT were performed in those patients who underwent peri-operative evaluation for vertebroplasty. The scans were evaluated separately to identify the "culprit" vertebra (e) by two readers and their results were analyzed. OBJECTIVE: Use of planar and SPECT bone scan for identifying the "culprit" vertebra (e) for vertebroplasty is well established. SPECT + CT is a relatively recent imaging tool providing co-registered fused images. Theoretical advantages of SPECT + CT over conventional SPECT imaging needs to be evaluated and documented. SUMMARY OF BACKGROUND DATA: Percutaneous stabilization of collapsed vertebra by bone cement has now become a standard procedure. However, it is essential to localize the correct vertebra. Imaging modalities like CT scan provides structural or anatomical information where as bone scan (planar + SPECT images) provides more functional or physiological information. Combination of these two imaging modalities is expected to provide much more than information obtained by any one imaging modality separately. To the best our knowledge, there is no reference available in the literature adopting this approach. MATERIALS AND METHODS: Two expert readers, blinded to patient history, evaluated the scans. They independently analyzed planar + SPECT only images followed by SPECT/CT fused images with the aim to identify the acutely fractured vertebra for vertebroplasty. RESULTS: Interpretations changed, on average, 50% of the time as a result of the additional information provided by SPECT + CT. SPECT + CT more precisely localizes tracer abnormalities in the vertebra compared to SPECT imaging alone. CONCLUSION: The greatest value of co-registered SPECT + CT bone scan lies in the accurate localization of affected vertebrae in complicated cases of multiple collapsed vertebrae of different ages as well as in the post-vertebroplasty setting.

In vivo assay of folate receptors in nonfunctional pituitary adenomas with 99mTc-folate SPECT/CT.

UNLABELLED: The objective of this study was to evaluate the in vivo assay of folate receptors in nonfunctional pituitary adenomas using preoperative (99m)Tc-folate SPECT/CT and Western blot analysis (WBA) of surgical specimens as the standard. METHODS: Fifty-six patients (29 men, 27 women; age range, 29-82 y) with clinically nonfunctional pituitary adenomas on MRI underwent preoperative imaging using 666 MBq (18 mCi) of (99m)Tc-folate. SPECT/CT images and whole-body and lateral head planar images were acquired approximately 2 h after injection. Surgical resection took place within a week. WBA on a portion of the excised specimens assessed folate receptor expression in 49 patients. Attenuation-corrected (99m)Tc-folate SPECT/CT images were assessed qualitatively and quantitatively (maximal adenoma counts to background), with WBA as a standard. RESULTS: Integrated CT was useful for uptake localization and assisted region-of-interest placement. Qualitative interpretation of planar imaging yielded a sensitivity of 81% and specificity of 72%. Qualitative SPECT/CT yielded a sensitivity of 94% and specificity of 61%. Receiver-operating-characteristic curve analysis of quantitative uptake yielded a tumor-to-background cutoff ratio of 3.5, with a sensitivity of 81% and specificity of 83%. Scalp uptake yielded consistent results (over the brain, neck, and choroid plexus) for background when SPECT/CT misalignment artifacts were avoided. Detection of pituitary uptake on anterior-posterior and lateral images was hampered by facial uptake, which varied between patients. CONCLUSION: SPECT/CT of (99m)Tc-folate is an accurate method of assaying folate receptors in vivo and may provide a quantitative marker for identifying folate receptor-positive tumors. This method may also prove beneficial in selecting patients for folate-targeted therapy of clinically nonfunctional pituitary adenomas, for which there is currently no medical therapy.

Role of "Bovie" in spinal surgery: historical and analytical perspective.

INTRODUCTION: Several surgeons use electrocautery (Bovie) discreetly or avoid it completely with the fear of increasing the chances of postoperative infection and delaying wound healing. However, the experience of many other surgeons is different. The current authors have used Bovie extensively to perform a broad array of spinal surgeries. Their rate of infection in spinal surgery can be positively compared with the existing literature where Bovie has been used to variable extent. The purpose of this study is to project the authors' concept that the use of Bovie dissection in spinal surgery does not increase the chances of postoperative wound infection. METHODS: A MEDLINE search was carried out to determine various aspects of Bovie, including historical perspectives, circuit design, tissue response, effect on wound healing, determination of wound infection, and role of surgical smoke. The search also included the rate of infection after various spinal surgeries in the existing literature (up to 15%). MATERIALS: In the span of 5 years (1996-2000), 322 spinal surgeries of various kinds were performed at Children's Hospital Medical Center (Cincinnati, Ohio). Most of them were performed by the senior author (A.H.C.). There were 102 cases of idiopathic scoliosis (two infected [2%]), 53 cases of neuromuscular scoliosis (two infected [4%]), and 167 cases of other spinal surgeries (three infected [1.8%]). Of these seven patients who developed wound infection in the postoperative period, one had superficial and six had deep infection. The overall rate of wound infection was 2%. Development of infection elsewhere in the body after surgery, such as respiratory, pleural, or urinary tract infections, has not been included in this analysis. RESULTS: Despite the fact that the authors have extensively used Bovie in spinal surgery, their rate of postoperative wound infection is comparable with the rate of infection cited in the available literature where Bovie was used to a variable extent. It strongly suggests that the use of Bovie does not increase the chances of postoperative wound infection. DISCUSSION: The role of Bovie for musculoskeletal surgery in general and spinal surgery in particular is not well defined. A review of the available literature indicates that Bovie delays the wound healing and increases the chances of infection. The authors' experience with the Bovie and this indirect method of analysis suggest that Bovie does not increase the chances of infection. A detailed search of the literature has been presented along with historical and analytical perspectives. More clinical and experimental studies are needed to further substantiate this claim. If future publications describe the exact surgical technique, extent of the use of Bovie, infection containment (antibiotic) method used before, during, and after surgery, length of the operative exposure, duration of the surgery, and rate of infection, then a meta-analysis of the published clinical material from different centers could be performed, which would provide more comprehensive information.

Epiphyseal stapling and recombinant human growth hormone for correction of genu valgum in children with chronic renal insufficiency.

Genu valgum (GV) and growth retardation are known complications of chronic renal insufficiency (CRI) in children. Physeal stapling is the preferred method for GV correction, provided epiphyseal growth continues after stapling. Growth retardation in these children thus renders this mode of therapy unreliable. The only alternative is corrective osteotomy with the associated risks, such as non-union of bone and recurrence. The authors sought to determine if recombinant human growth hormone (rhGH) administered after stapling can bring about continued physeal growth needed for correction. The medical records of five patients with CRI, GV, and growth retardation who had physeal stapling performed and received rhGH were reviewed. Resolution of GV and improvement in linear height was achieved in four patients within 2 years. The authors conclude that children with CRI, growth retardation, and moderate GV benefit from the simultaneous use of rhGH and knee stapling for correction of GV, thus avoiding osteotomies.