Exoproteome of Aspergillus flavus corneal isolates and saprophytes: identification of proteoforms of an oversecreted alkaline protease

Aspergillus flavus infects the human eye leading to keratitis. Extracellular proteins, the earliest proteins that come in contact with the host and virulence related exoproteins, were identified in the fungus isolated from infected cornea. Virulence of the corneal isolates was tested in the Galleria mellonella larvae model and those isolates showing higher virulence were taken for subsequent exoproteome analysis. High resolution two-dimensional electrophoresis and mass spectrometry were used to generate A. flavus exoproteome reference map as well as to profile most of the exoproteins. Analysis of the identified proteins clearly shows the major biological processes that they are involved in. Nearly 50% of the exoproteins possess catalytic activity and one of these, an alkaline serine protease (Alp1) is present in high abundance as well as multiple proteoforms. Many proteins in the A. flavus exoproteome have been shown to be virulence factors in other pathogens indicating the probable role for these proteins in the corneal infection as well. Interestingly, the majority of the exoproteins do not have secretory signal indicating that they are secreted through the non-classical pathway. Thus, this study provides a clue to the early strategies employed by the pathogen to establish an infection in an immunocompetent host.

BIOLOGICAL SIGNIFICANCE

The outcome of a fungal infection in an immunocompetent human eye depends on the ability of the fungus to overcome the host defense and propagate itself. In this process, the earliest events with respect to the fungal proteins involved include the secretory proteins of the invading organism. As a first step towards understanding the role of the extracellular proteins, exoproteome profile of the fungal isolates was generated. The fungal isolates from cornea showed a distinct pattern of the exoproteome when compared to the saprophyte. Since corneal isolates also showed higher virulence in the insect larval model, presumably the proteins elaborated by the corneal isolates are virulence related. One of the abundant proteins is an alkaline serine protease and this protein exists as multiple proteoforms. This study reports the comprehensive profile of exoproteome and reveals proteins that are potential virulence factors.

Functional characterization of a small heat shock protein from Mycobacterium leprae

BACKGROUND

Small heat shock proteins are ubiquitous family of stress proteins, having a role in virulence and survival of the pathogen. M. leprae, the causative agent of leprosy is an uncultivable organism in defined media, hence the biology and function of proteins were examined by cloning M. leprae genes in heterologous hosts. The study on sHsp18 was carried out as the knowledge about the functions of this major immunodominant antigen of M. leprae is scanty.

RESULTS

The gene encoding Mycobacterium leprae small heat shock protein (sHsp18) was amplified from biopsy material of leprosy patients, and cloned and expressed in E. coli. The localization and in vitro characterization of the protein are detailed in this report. Data show that major portion of the protein is localized in the outer membrane of E. coli. The purified sHsp18 functions as an efficient chaperone as shown by their ability to prevent thermal inactivation of restriction enzymes SmaI and NdeI. Physical interaction of the chaperone with target protein is also demonstrated. Size exclusion chromatography of purified protein shows that the protein can form multimeric complexes under in vitro conditions as is demonstrated for several small heat shock proteins.

CONCLUSION

The small heat shock protein sHsp18 of M. leprae is a chaperone and shows several properties associated with other small heat shock proteins. Membrane association and in vitro chaperone function of sHsp18 shows that the protein may play a role in the virulence and survival of M. leprae in infected host.

Angiomyoma of the knee joint: value of magnetic resonance imaging

A case of angiomyoma as an unusual cause of knee pain is presented and the usefulness of magnetic resonance imaging in such a situation is discussed.

Multicenter Evaluation of Diagnostic Circulating Biomarkers to Detect Sight-Threatening Diabetic Retinopathy

Question

Can circulating serum biomarkers distinguish people with sight-threatening diabetic retinopathy (STDR) from those with no DR?

Findings

This multicenter cross-sectional study of 538 participants found an incremental benefit of circulating cystatin C beyond the standard clinical variables in discriminating STDR from no DR. Cystatin C outperformed 12 other biomarkers found to be distinguished in STDR in previous research.

Meaning

Results of this study suggest the consideration of circulating cystatin C levels as a triage test in prioritizing people with type 2 diabetes from the community for retinal screening in resource-restricted settings.

Importance

It is a global challenge to provide regular retinal screening for all people with diabetes to detect sight-threatening diabetic retinopathy (STDR).

Objective

To determine if circulating biomarkers could be used to prioritize people with type 2 diabetes for retinal screening to detect STDR.

Design, Setting, and Participants

This cross-sectional study collected data from October 22, 2018, to December 31, 2021. All laboratory staff were masked to the clinical diagnosis, assigned a study cohort, and provided with the database containing the clinical data. This was a multicenter study conducted in parallel in 3 outpatient ophthalmology clinics in the UK and 2 centers in India. Adults 40 years and older were categorized into 4 groups: (1) no history of diabetes, (2) type 2 diabetes of at least 5 years’ duration with no evidence of DR, (3) nonproliferative DR with diabetic macular edema (DME), or (4) proliferative DR. STDR comprised groups 3 and 4.

Exposures

Thirteen previously verified biomarkers were measured using enzyme-linked immunosorbent assay.

Main Outcomes and Measures

Severity of DR and presence of DME were diagnosed using fundus photographs and optical coherence tomography. Weighted logistic regression and receiver operating characteristic curve analysis (ROC) were performed to identify biomarkers that discriminate STDR from no DR beyond the standard clinical parameters of age, disease duration, ethnicity (in the UK) and hemoglobin A_1c.

Results

A total of 538 participants (mean [SD] age, 60.8 [9.8] years; 319 men [59.3%]) were recruited into the study. A total of 264 participants (49.1%) were from India (group 1, 54 [20.5%]; group 2, 53 [20.1%]; group 3, 52 [19.7%]; group 4, 105 [39.8%]), and 274 participants (50.9%) were from the UK (group 1, 50 [18.2%]; group 2, 70 [25.5%]; group 3, 55 [20.1%]; group 4, 99 [36.1%]). ROC analysis (no DR vs STDR) showed that in addition to age, disease duration, ethnicity (in the UK) and hemoglobin A_1c, inclusion of cystatin C had near-acceptable discrimination power in both countries (area under the receiver operating characteristic curve [AUC], 0.779; 95% CI, 0.700-0.857 in 215 patients in the UK with complete data; AUC, 0.696; 95% CI, 0.602-0.791 in 208 patients in India with complete data).

Conclusions and Relevance

Results of this cross-sectional study suggest that serum cystatin C had good discrimination power in the UK and India. Circulating cystatin-C levels may be considered as a test to identify those who require prioritization for retinal screening for STDR.

Protective role of Mycobacterium leprae small heat-shock protein in heterologous hosts, Escherichia coli and Mycobacterium smegmatis, grown under stress

The aim of this study is to examine the in vivo role of a small heat-shock protein (sHsp18) from Mycobacterium leprae in the survival of heterologous recombinant hosts carrying the gene encoding this protein under different environmental conditions that are normally encountered by M. leprae during its infection of the human host. Using an Escherichia coli system where shsp18 expression is controlled by its native promoter, we show that expression of shsp18 is induced under low oxygen tension, nutrient depletion and oxidative stress, all of which reflect the natural internal environment of the granulomas where the pathogen resides for long periods. We demonstrate the in vivo chaperone activity of sHsp18 through its ability to confer survival advantage to recombinant E. coli at heat-shock temperatures. Additional evidence for the protective role of sHsp18 was obtained when Mycobacterium smegmatis harbouring a copy of shsp18 was found to multiply better in human macrophages. Furthermore, the autokinase activity of sHsp18 protein demonstrated for what is believed to be the first time in this study implies that some of the functions of sHsp18 might be controlled by the phosphorylation state of this protein. Results from this study suggest that shsp18 might be one of the factors that facilitate the survival and persistence of M. leprae under stress and autophosphorylation of sHsp18 protein could be a mechanism used by this protein to sense changes in the external environment.

Comparative proteomics of proliferative diabetic retinopathy in people with Type 2 diabetes highlights the role of inflammation, visual transduction, and extracellular matrix pathways

Purpose

To explore the vitreous humor proteome from type 2 diabetes subjects with proliferative diabetic retinopathy (PDR) in the Indian population.

Methods

We performed mass spectrometry-based label-free quantitative analysis of vitreous proteome of PDR (n = 13) and idiopathic macular hole (IMH; control) subjects (n = 14). Nine samples of PDR and 10 samples of IMH were pooled as case and control, respectively, and compared. Four samples each of PDR and IMH were analyzed individually without pooling to validate the results of the pooled analysis. Comparative quantification was performed using Scaffold software which calculated the fold changes of differential expression. Bioinformatics analysis was performed using DAVID and STRING software.

Results

We identified 469 proteins in PDR and 517 proteins in IMH vitreous, with an overlap of 172 proteins. Also, 297 unique proteins were identified in PDR and 345 in IMH. In PDR vitreous, 37 proteins were upregulated (P < 0.05) and 19 proteins were downregulated compared to IMH. Protein distribution analysis clearly demonstrated a separation of protein expression in PDR and IMH. Significantly upregulated proteins included fibrinogen gamma chain, fibrinogen beta chain, and carbonic anhydrase 1 and downregulated proteins included alpha-1-antitrypsin, retinol-binding protein 3, neuroserpin, cystatin C, carboxypeptidase E and cathepsin-D.

Conclusion

Diabetic retinopathy pathogenesis involves proteins which belong to inflammation, visual transduction, and extracellular matrix pathways. Validation-based experiments using enzyme-linked immunosorbent assay (ELISA) or western blotting are needed to establish cause and effect relationships of these proteins to the disease state, to develop them as biomarkers or drug molecules.

Data set for the mass spectrometry based exoproteome analysis of Aspergillus flavus isolates

Aspergillus flavus is one of the predominant causative organisms of mycotic keratitis in tropical parts of the world. Extracellular proteins are the earliest proteins that come in contact with the host and have a role in the infection process. Exoproteins of A. flavus isolated from infected cornea, sputum and a saprophyte were pooled and identified using high resolution mass spectrometry in order to get the total exoproteome from cultures isolated from different sources. A total of 637 proteins was identified from the pooled A. flavus exoproteome. Analysis based on GO annotations of the 637 identified proteins revealed that hydrolases form the predominant class of proteins in the exoproteome. Interestingly, a greater proportion of the exoproteins seem to be secreted through the non-classical pathways. This data represent the first in-depth analysis of the representative A. flavus exoproteome of a large set of isolates from distinct sources. This data have been deposited to the ProteomeXchange with identifier PXD001296.

Pseudarthrosis of the surgical neck of humerus treated by buttressing with a medial cortico-cancellous graft

BACKGROUND

Pseudarthrosis of surgical neck of humerus is uncommon condition. Different methods of improving the stability of fixation have been described, including impaling the shaft into the head, placing a tension suture through the rotator cuff, or using an intramedullary cortical graft. We report our results of cortico-cancellous strut graft medially to counter the varus force, in conjunction with a fixed-angle implant on the lateral side.

MATERIALS AND METHODS

We used this technique in seven cases of pseudarthrosis of surgical neck of the humerus. There were four women and three men, ranging in age from 22 to 65 years. All were treated with a tricortical medial buttress bone graft and fixed-angle fixation device on the lateral side. A locking proximal humerus plate (Synthes) was used in six cases, and a bent reconstruction plate (Synthes) was applied in one case. The one in which reconstruction plate was applied was operated before the advent of locking plates. The limb was immobilized in 30° of abduction over a cushion for 6 weeks, followed by a sling for another 6 weeks.

RESULTS

The followup varied from 18 to 96 months. All our cases healed within mean 5.1 months (range 4-6 months). There was one case of avascular necrosis. All cases had useful function of shoulder.

CONCLUSION

The medial buttressing by strut graft with external fixation by laterally placed fixed angle plate is successful to achieve fracture union in pseudarthrosis of surgical neck of humerus.

Interactions between rearward-facing child restraint systems and the front row seatback in frontal impact sled tests

OBJECTIVE

Some child restraint system (CRS) manufacturers specify a minimum distance between the CRS and the seatback, whereas others require that the CRS may contact the seatback but cannot be "braced"; however, few studies have investigated these interactions. Therefore, the aim was to investigate the interactions between the front row seat and rearward-facing CRS models with and without a support leg during frontal crashes.

METHODS

Sled tests using the FMVSS 213 frontal crash pulse were performed with the Q1.5 and Q3 anthropomorphic test devices (ATDs) seated in rearward-facing infant and convertible CRS models, respectively. A front row vehicle seat was in front of the test bench in three track positions: brace, touch and gap. For the touch condition, the front row seat was translated aftward until the seatback contacted the CRS. For the brace condition, the front row seat was translated 20 mm aftward. For the gap condition, the front row seat was translated 50 mm forward. Each condition was tested with and without the support leg of the CRS.

RESULTS

The tests with a support leg were associated with significantly (p = 0.007) lower resultant linear head acceleration 3 ms clip compared to the tests without a support leg, but the reduction of head injury criterion 15 ms (HIC15) was not significant (p = 0.057). The Q1.5 ATD in the rearward-facing infant CRS with a support leg had the lowest injury metrics for the touch and gap conditions, whereas the Q3 in the rearward-facing convertible CRS had the lowest head injury metrics for the brace condition.

CONCLUSIONS

The use of a support leg provided a clear benefit in terms of reducing head injury metrics for the Q1.5 in the rearward-facing infant CRS, especially for the touch and gap conditions. The rearward-facing convertible CRS in the current study appears to benefit from being braced against the front row seat. However, further tests are required to allow further statistical comparisons and determine if these preliminary findings extend to other rearward-facing CRS models.

Characterizing neck and spinal response in booster seated reclined children in frontal impacts

OBJECTIVE

Belt-positioning booster seats (BPB) and pre-pretensioner (PPT) belts may be effective in preventing injuries from submarining and head excursion in reclined children. It is unknown if injuries at the neck and spine could still occur. This study's goal is to characterize neck and spine responses in reclined children with and without the BPB and the PPT.

METHODS

Eleven frontal impact sled tests were performed (56 kph) with the Large Omnidirectional Child (LODC) dummy on a production vehicle seat. A 3-point simulated seat-integrated-belt was used with a load-limiter (∼4.5 kN). Testing was conducted with and without the BPB with the seatback at ∼25°, ∼45° and repeated once. One test was conducted at ∼60° with the BPB. 100 mm of belt-slack was removed to simulate PPT in two 45° BPB tests and the BPB 60° test. The LODC peak thoracic spine accelerations and angular rotations, and peak neck and lumbar force/moment loads were compared between conditions.

RESULTS

Neck shear forces were the highest in the 60° BPB & PPT (-1.9 kN) and 45° noBPB (-1.3 kN) than all other BPB conditions (-0.5 to -0.8 kN). The highest peak neck moments were found in the 45° noBPB (-40.5 N-m), and in the 60° BPB & PPT (-34.2 N-m) conditions compared to all others (-20.8 to -27.9 N-m.). The 60° BPB and PPT condition demonstrated thoracic forward rotation similar to the 25° noBPB condition (25° noBPB -24.8 to -35.0 deg, 60° BPB&PPT -27.5 to -43.2 deg.). Thoracic spine peak resultant accelerations (T1, T6, T12) were higher in the 25° and 45° noBPB conditions (53 g to 71 g) and in the 60° BPB & PPT (T6: 61.8 g) compared to all other BPB conditions (48.4 g to 53.1 g). The lumbar peak shear forces and moments were the highest in the 45° noBPB (4.9 kN, -296 N-m) and the 60° BPB & PPT condition (1.7 kN, -146 N-m).

CONCLUSION

These findings show similarities in neck, spine, and lumbar responses between the 60° reclined condition with BPB and PPT and the 25° and 45° conditions without the same countermeasures. This study highlights the need for future restraint developments to protect moderate and severe reclined BPB-seated child occupants.

Factors Affecting Implant Failure in Fracture of the Shaft of Femur

17 cases of implant failure of fracture of shaft of femur were studied. All cases were young adults less than40 years of age. 15 were males. 16 of 17 cases sustained their initial injury in road - traffic accidents. Platefailures were detected earlier than those of nails as nails kept on providing splintage to an otherwise ununitedfracture. 10 of 17 cases were treated by interlocking nailing during the resurgery. Cortico-cancellous bonegrafting was done in 9 of 17 cases as per merit of each case. Follow-up ranged from 6 months to 2 years. 15of 17 cases went on to sound union after the second operation.The wrong choice of implant, implants improperly applied and bone grafting not done as recommended(i.e. technical errors) is the major cause of implant failure. Nails with diameter more than 10 mm should beused as far as possible. Early detection and resurgery for K-nail failure should be done to prevent greateramount of shortening. Wherever plating is done, instead of attempting anatomic reduction and devascularisingthe bone, biological method of fixation should be used.Key Words: Implant Failure, Shaft of Femur, Fracture.

Head excursions of rearward-facing child restraint systems in rear impacts

OBJECTIVE

The aim of the current study was to quantify the head excursions of pediatric anthropomorphic test devices (ATDs) seated in rearward-facing child restraint system (CRS) models during rear impact sled tests and compare to roof heights of vehicles in the current fleet to assess the possibility of head contact against the vehicle roof.

METHODS

Head excursions of ATDs seated in rearward-facing CRS models were analyzed from high-speed video data from 14 rear impact sled tests across two different series. Tests were conducted in rigidized vehicle seats from recent model year vehicles. Rearward-facing infant and convertible CRS models were tested with a variety of pediatric ATDs aged 12 months to 6 years in a variety of installation conditions (e.g., lower anchors or seat belt, anti-rotation features, etc). Maximum ATD head excursions in plane of the seatback were compared to previously measured roof heights of 87 different vehicles.

RESULTS

The roof heights in all sedan seating positions (n = 58) and SUV/CUV/minivan seating positions (n = 60) were greater than the largest maximum ATD head excursions in plane of the seatback (792 mm). Head contact was possible in two of the pickup trucks which had roof heights of 730 and 775 mm. In all, 98% of vehicle seating positions measured in this study would accommodate all of the maximum ATD head excursions in plane of the seatback without contact.

CONCLUSIONS

The risk of head contact against the vehicle interior roof appears low as maximum ATD head excursions in plane of the seatback were typically not great enough to reach the rooflines of the vehicles in the sample. Head contact appears possible in pickup trucks, where the window/roofline is directly behind the head restraint.

Analysis of Kinematic Response of Pediatric Occupants Seated in Naturalistic Positions in Simulated Frontal Small Offset Impacts: With and Without Automatic Emergency Braking

Naturalistic driving studies have shown that pediatric occupants do not assume ideal seating positions in real-world scenarios. Current vehicle assessment programs and child restraint system (CRS) sled tests, such as FMVSS No. 213, do not account for a wide range of seating postures that are typically observed during real-world trips. Therefore, this study aims to analyze the kinematic and kinetic response of a pediatric human body model in various naturalistic seating positions in booster seats when subjected to a frontal offset impact in a full-vehicle environment, with and without the application of pre-crash automatic emergency braking (AEB). A 6YO (seated on a lowback and highback booster) and a 10YO (seated in no-CRS and on a lowback booster) PIPER pediatric human body model's response was explored in a reference, and two most commonly observed seating postures: forward-leaning and forward-inboard-leaning. The vehicle environment with a side-curtain airbag (SCAB) was subjected to a small offset barrier impact (25% overlap at 40MPH), with and without the application of a pre-crash automatic emergency braking (AEB). 24 conditions were simulated using finite element analysis. Cases with a pre-crash AEB resulted in relatively lower kinematic and kinetic values due to the occupant being in a more flexed position before impact compared to without-AEB cases, coupled with the increased ride-down effect due to AEB. Moreover, different seating postures resulted in substantially different kinematics and kinetics, the injury metrics crossing the injury assessment reference values in some cases. Therefore, to design a passive safety standard test for pediatric occupants, it is important to consider the possible postural changes that may occur.

COVID 19 Care Call-in Helpline. A Report from India

A COVID 19 call helpline was established by a noted TV channel along with a group of consultant doctors at the height of the second wave COVID 19 pandemic in India. It helped the general public to understand dos and donts as well as long term implications. We retrospectively analysed the questions asked to get a feel of the misunderstandings and perceptions within the general public. Many quereies related to the vaccination drive.

Interactions between rearward-facing child restraint systems and the center console in frontal impact sled tests

OBJECTIVE

To quantify the head and chest injury metrics associated with a pediatric anthropomorphic test device (ATD) in rearward-facing infant child restraint system (CRS) models positioned directly behind a center console during frontal impact sled tests.

METHODS

Sled tests using the Federal Motor Vehicle Safety Standard (FMVSS) 213 frontal crash pulse were performed. The test buck comprised a second row middle seat and center console from the same 2023 model mid-size SUV spaced as per the in-vehicle relative dimensions, a force plate covered with an automotive floor mat, a post-mounted shoulder belt simulating the in-vehicle roof-mounted seatbelt and an array of high-speed cameras. The 12-month-old Child Restraint/Air Bag Interaction (CRABI-12) ATD was seated in one of two rearward-facing infant CRS models (model A, rigid lower anchors; model B, flexible lower anchors), which was installed with either the base (support leg or no support leg; attached using lower anchors or the seatbelt) or without the base (attached using the European or US belt path). Conductive foil was attached to the rear surface of the center console and to the shell of the CRS and/or base to quantify contact. The vehicle seat was replaced every second test and the center console was replaced when damaged.

RESULTS

For sled tests of the CRS models with a base attached using lower anchors, there was no contact of the CRS with the center console when the support leg was used, and all head and chest injury metrics were reduced compared to the tests of CRS with no support leg. However, there was contact between the CRS and the center console when the base of the CRS models was attached using the seatbelt, which typically increased head and chest injury metrics compared to the lower anchor attachment method. For CRS model B with the base attached using either the lower anchors or the seatbelt but no support leg, head acceleration 3 ms clip exceeded the injury assessment reference value (IARV) of 80 g. All tests resulted in HIC36 values below the IARV of 1000. The tests of the CRS models without a base using the European belt path did not result in contact and had the lowest head and chest injury metrics of all tests, which were all below IARVs. For the tests of the CRS models with the base attached using the seatbelt and tests using the US belt path, chest acceleration 3 ms clip values exceeded the IARV of 60 g. Peak normal support leg reaction forces in this study ranged from 3.6 to 4.3 kN.

CONCLUSIONS

The rearward-facing CRS models with a base and a support leg attached using lower anchors, or without a base using the European belt path, resulted in the lowest head and chest injury metrics due to not contacting the center console.

Management of type III acromioclavicular joint dislocation: A Delphi consensus survey by Shoulder & Elbow Society, India (SESI)

PURPOSE

The study aimed to report the results of the Delphi survey conducted by the Shoulder, Elbow Society India (SESI), to achieve consensus on ambiguous topics in managing type III acromioclavicular joint (ACJ) dislocations.

METHODS

This study was based on responses from the Shoulder Elbow Society India (SESI) panel of peer-selected twenty senior surgeons practicing shoulder orthopedics. They participated in two rounds of the survey to obtain consensus on several topics pertaining to the management of type III ACJ dislocations. Consensus was achieved when at least 70 % of the panel members selected at least a 4-point on a 5-point Likert scale.

RESULTS

Our Delphi survey reached a consensus on seven topics of ambiguity. An anteroposterior and axillary view of the shoulder without any traction or weight in hand is sufficient in the setting of a suspected type III ACJ dislocation. Magnetic resonance imaging (MRI) is not routinely indicated in type III ACJ dislocation. Either cross-arm adduction X-rays or clinical examination may be used to distinguish between ISAKOS (International Society of Arthroscopy, Knee surgery and Orthopaedics Sports medicine) IIIA and B classification of ACJ to identify stable and unstable injuries. Conservative treatment can be offered to patients who have stable injuries and who are not high-demand individuals in acute type III ACJ dislocations. In conservative management of type III ACJ dislocation, a two-week sling suffices. Jones strapping has no clear advantage over a shoulder sling. Coracoclavicular reconstruction with an autograft is an acceptable way to treat symptomatic, chronic grade III ACJ dislocation.

CONCLUSION

The survey helped achieve consensus on several controversial issues related to type III ACJ dislocations. However, there remains ambiguity on the definition of chronicity of such dislocations, the necessity of bilateral Zanca views, and the duration of conservative trial before switching to a surgical line of management.