A New and Highly Sensitive Serum Mannoprotein Lateral Flow Assay for Point-of-Care Diagnosis of Invasive Aspergillosis (Tripathy Method)

Background and objectives

The mannoprotein lateral flow assay (MP-LFA) or Aspergillus-specific lateral flow device (AspLFD) is a novel rapid test for point-of-care diagnosis (PoC) of invasive aspergillosis (IA), but its routine clinical application is hampered due to low sensitivity (S_n) of the assay in serum. Therefore, this study aimed to develop a new method to enhance the S_n of the serum MP-LFA.

Methodology

In the new method (Tripathy method), we used direct heating of the serum without any dilution at 120^°C for 15 minutes to purify the mannoprotein (MP) antigen of the Aspergillus. The MP-enriched serum supernatant obtained after centrifugation was loaded in an LFD cassette, and the results were read after 20 minutes using a digital cube reader. In parallel to our new method, AspLFD was performed according to the manufacturer’s instructions. The diagnostic performance of the two methods was evaluated using paired sera of true IA patients (IA, n=18) and healthy subjects (controls, n=20). The positivity of the two methods was also evaluated in the sera of leukemia patients with possible/probable IA (possible/probable IA; n=23).

Results

The Tripathy method had a significantly higher sensitivity (88.9% versus 55.5%; p<0.05) and diagnostic odds ratio (72.0 versus 23.7) than the standard AspLFD method. In receiver operating characteristic curve analysis for differentiation between IA patients and controls, although the Tripathy method (area under curve; AUC: 0.894, p<0.001) and AspLFD method (AUC: 0.753, p<0.001) were significantly associated with IA, the AUC of the Tripathy method was significantly higher than that of the AspLFD method (0.894 versus 0.753; p<0.05). In the sera of possible/probable IA, MP-LFA by the Tripathy method had a significantly higher rate of positivity than the AspLFD method (39.0% versus 21.7%; p<0.05).

Conclusion

Our data show that the Tripathy method is a highly sensitive method of MP-LFA for the PoC diagnosis of IA in clinical settings.

Practice Guidelines for the Diagnosis of COVID-19-Associated Pulmonary Aspergillosis in an Intensive Care Setting

Coronavirus disease-2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) is a new disease characterized by secondary Aspergillus mold infection in patients with COVID-19. It primarily affects patients with COVID-19 in critical state with acute respiratory distress syndrome, requiring intensive care and mechanical ventilation. CAPA has a higher mortality rate than COVID-19, posing a serious threat to affected individuals. COVID-19 is a potential risk factor for CAPA and has already claimed a massive death toll worldwide since its outbreak in December 2019. Its second wave is currently progressing towards a peak, while the third wave of this devastating pandemic is expected to follow. Therefore, an early and accurate diagnosis of CAPA is of utmost importance for effective clinical management of this highly fatal disease. However, there are no uniform criteria for diagnosing CAPA in an intensive care setting. Therefore, based on a review of existing information and our own experience, we have proposed new criteria in the form of practice guidelines for diagnosing CAPA, focusing on the points relevant for intensivists and pulmonary and critical care physicians. The main highlights of these guidelines include the role of CAPA-appropriate test specimens, clinical risk factors, computed tomography of the thorax, and non-culture-based indirect and direct mycological evidence for diagnosing CAPA in the intensive care unit. These guidelines classify the diagnosis of CAPA into suspected, possible, and probable categories to facilitate clinical decision-making. We hope that these practice guidelines will adequately address the diagnostic challenges of CAPA, providing an easy-to-use and practical algorithm to clinicians for rapid diagnosis and clinical management of the disease.

Laccase- and peroxidase-free tyrosinase production by isolated microbial strain

Laccase- and peroxidase-free tyrosinase has commercial importance in the production of L-3, 4-dihydroxyphenylalanine (L-DOPA), which is mainly used in the treatment of Parkinson's disease. In the present study, isolation of an actinomycetes microbial strain capable of producing only tyrosinase is reported. Among all soil isolates, three individual colonies revealed black color around the colony in the presence of tyrosine. Further screening for laccase and peroxidase activities using syringaldazine denoted that one of the isolates, designated as RSP-T1, is laccase and peroxidase negative and produces only tyrosinase. The microbe was authenticated as Streptomyces antibioticus based on 16S ribotyping. Effective growth of this isolate was noticed with the use of medium (pH 5.5) containing casein acid hydrolysate (10.0 g/l), K(2)HPO(4) (5.0 g/l), MgSO(4) (0.25 g/l), L-tyrosine (1.0 g/l), and agar (15 g/l). The scanning electron micrograph depicted that the microbe is highly branched and filamentous in nature. The enzyme production was positively regulated in the presence of copper sulfate. The impact of different fermentation parameters on tyrosinase production depicted that the maximized enzyme titer values were observed when this isolate was grown at 6.5 pH and at 30 degrees C temperature under agitated conditions (220 rpm). Among all the studied physiological parameters, agitation played a significant role on tyrosinase production. Upon optimization of the parameters, the yield of tyrosinase was improved more than 100% compared with the initial yield.

Soluble endothelial cell adhesion molecules and their relationship to disease activity in Takayasu's arteritis

OBJECTIVE

To investigate soluble (s) E-selectin, vascular cell adhesion molecule-1 (VCAM-1), and intercellular cell adhesion molecule-1 (ICAM-1), and their relationship to disease activity in Takayasu's arteritis (TA).

METHODS

Levels of adhesion molecules were measured by enzyme immunoassay in the sera of 35 patients with TA, 17 healthy controls, and 15 patients with 12 months followup.

RESULTS

Compared to controls, patients had elevated levels of sE-selectin (54.5 +/- 35.0 vs 36.4 +/- 13.0 ng/ml, p < 0.05), sVCAM-1 (280.9 +/- 267.6 vs 141.2 +/- 76.1 ng/ml, p < 0.05), and sICAM-1 (261.3 +/- 168.1 vs 198.3 +/- 74.3 ng/ml, p < 0.05). Compared to controls, patients with inactive TA also had elevated levels of sE-selectin (67.4 +/- 45.9 vs 36.4 +/- 13.0 ng/ml, p < 0.02), sVCAM-1 (327.6 +/- 327.8 vs 141.2 +/- 76.1 ng/ml, p < 0.02), and sICAM-1 (321.9 +/- 179.5 vs 198.3 +/- 74.3 ng/ml, p < 0.02). There was no difference between active TA and controls. sE-selectin had a trend towards increased levels in inactive versus active TA (67.4 +/- 45.9 vs 44.9 +/- 20.3 ng/ml p = 0.059), but there was no difference in sVCAM-1 and sICAM-1 levels between the groups. No adhesion molecule levels showed a change among followup patients.

CONCLUSION

Patients with inactive TA have elevated levels of sE-selectin, sVCAM-1, and sICAM-1 that might indicate persistent vasculopathy in clinically inactive disease.

Interleukin 12 in Takayasu's arteritis: plasma concentrations and relationship with disease activity

OBJECTIVE

To investigate plasma concentrations of interleukin 12 (IL-12) and their relationship with disease activity in patients with Takayasu's arteritis (TA).

METHODS

IL-12 levels were determined by quantitative enzyme immunoassay in the plasma of 80 patients with TA, 25 age/sex matched healthy controls, and 15 followup patients with active TA on immunosuppressive therapy.

RESULTS

Significantly increased levels of IL-12 were observed in patients with TA versus controls (90.6 +/- 365.3 vs 6.9 +/- 11.3 pg/ml; p < 0.05) and in patients with active versus inactive TA (168.7 +/- 507.0 vs 12.6 +/- 26.9 pg/ml; p = 0.005). The prevalence of IL-12 (the cytokine levels above cutoff value) was higher in patients than in controls [44% (35/80) vs 12% (3/25); p < 0.01] and in patients with active versus inactive TA [57% (23/40) vs 30% (40); p < 0.05]. Six of the 9 patients who became inactive on followup also had normalized levels of IL-12.

CONCLUSION

The data indicate that IL-12 might be an important mediator of inflammation in TA.

Interleukin-8 in Takayasu's arteritis: plasma levels and relationship with disease activity

OBJECTIVE

To investigate the plasma levels of interleukin-8 (IL-8) in Takayasu's arteritis (TA) and their relationship with disease activity.

METHODS

IL-8 levels were detected by quantitative enzyme-linked immunosorbent assay (ELISA) in the plasma of 53 TA patients, 25 age/sex-matched healthy controls and of 10 serially followed up active TA patients on immunosuppressive therapy.

RESULTS

Significantly increased levels of IL-8 were observed in TA patients (26.32 +/- 48.96 pg/ml) compared to controls (6.0 +/- 2.45 pg/ml) (p = 0.0006) and in patients with active TA (55.0 +/- 71.43 pg/ml) compared to those with an inactive disease (8.94 +/- 6.35 pg/ml) (p = 0.0001). The increased levels of the chemokine were present in 37% (20/53) of the patients compared to 8% (2/25) of the controls (p < 0.01) and in 80% (16/20) of patients with active TA compared to 12% (4/33) of those with an inactive disease (p < 0.0001). In the follow-up study, the plasma levels of IL-8 were normalized in 6/10 of the patients and the disease in 5 of these 6 patients was also observed to undergo remission.

CONCLUSION

These results suggest that IL-8 may play an important role in the pathogenesis of TA.

Anti-annexin V antibodies in Takayasu's arteritis: prevalence and relationship with disease activity

Annexin V has an important role in the regulation of apoptosis and antibodies directed against it have been shown to lead to apoptosis of vascular endothelial cells. To evaluate the role of anti-annexin V antibodies (AA5A) in Takayasu's arteritis (TA), we investigated these antibodies in the sera of 66 TA patients, 50 healthy controls and in the follow-up sera of 12 active TA patients by enzyme-linked immunosorbent assay. The AA5A-positive patients were analysed further for the presence of anti-endothelial cell antibodies (AECA) and anticardiolipin antibodies (ACLA) to determine the relationship of AA5A with these autoantibodies. AA5A were observed in 36% (24/66) of the patients versus 6% (3/50) of the controls (P<0.001) and in 53% (19/36) of patients with active TA versus 17% (5/30) of those with inactive disease (P<0.01). Levels of AA5A were also observed to be significantly higher in patients with TA compared to controls (0.557 +/- 0.362 versus 0.259 +/- 0.069; P<0.0001) and in patients with active disease compared to those with inactive disease (0.700 +/- 0.403 versus 0.385 +/- 0.205; P<0.0001). In the follow-up study, 6/12 patients who became inactive during follow-up also showed normalization of AA5A levels. AECA and ACLA were detected in 54% (13/24) and 12% (3/24) of the AA5A-positive patients, respectively. Our results show that a significant proportion of TA patients have AA5A, which exhibit an association with AECA and because they have a correlation with disease activity thus appear to be involved in the disease pathogenesis.

Effect of dimecron on the blood parameters of Heteropneustes fossilis

The effects of an organophosphate insecticide. dimecron. has been studied on certain haematological parameters, viz., haemoglobin concentration, RBC number, haematocrit, O2 carrying capacity of blood, etc. of Heteropneustes fossilis following exposures to the LC50 for 24 h and 96 h and 1/10 and 1/50 parts of 96 h LC50 for 90 days. There was a significant decrease in the Hb%, RBC number, HCt% and O2 carrying capcity of blood. But, there was significant increase in the MCH and MCV values following both acute and chronic exposures. The results indicate possible induction of anaemia in the exposed fish.

Complement and cell mediated cytotoxicity by antiendothelial cell antibodies in Takayasu's arteritis

OBJECTIVE

To study complement and cell mediated cytotoxicity by antiendothelial cell antibodies (AECA) in Takayasu's arteritis (TA).

METHODS

Complement dependent cytotoxicity (CDC) and antibody dependent cellular cytotoxicity (ADCC) of AECA positive/negative TA sera were investigated by colorimetric MTT and 51Cr release assays, respectively, using human umbilical vein endothelial cells (HUVEC) as targets.

RESULTS

Seven of 12 (58%) sera positive for IgG and/or IgM AECA exhibited CDC in comparison to none of the 13 AECA negative sera (p = 0.0052). The median value of CDC of the AECA positive group was 14% (range 13-21%) and that of the AECA negative group was 1% (p = 0.0012). Interleukin 1beta (10 U/ml) treatment of HUVEC resulted in enhancement in CDC of 6 of the 7 AECA positive cytotoxic sera, the median enhancement being 17% (range 7-29%). Tumor necrosis factor-alpha (100 U/ml) treatment of the targets resulted in a median enhancement by 36% (range 25-55%) in the CDC of 3 of these 7 sera. No sera exhibited ADCC at any of the effector:target ratios tested (10:1 to 100:1).

CONCLUSION

AECA in TA mediate CDC against endothelial cells and may have a pathogenic role in the perpetuation of vascular damage in this disease.

Antiendothelial cell antibodies in scleroderma correlate with severe digital ischemia and pulmonary arterial hypertension

OBJECTIVE

To determine the prevalence of IgG antiendothelial cell antibodies (AECA) in patients with scleroderma (systemic sclerosis, SSc) and to correlate it with clinical spectrum and autoantibody profile.

METHODS

Seventy-six patients with SSc and 50 matched healthy controls were studied. Immunological variables were antinuclear antibody (ANA), rheumatoid factor (RF), and Scl-70. IgG-AECA was measured by cellular ELISA.

RESULTS

The prevalence of IgG-AECA was 27.6% in patients with SSc compared to 6% in controls (p < 0.01). Forty percent of patients with diffuse disease had this antibody, versus 13.5% of those with limited cutaneous involvement (p < 0.05). Patients with AECA had significantly higher incidence of digital infarcts and gangrene (p < 0.01) and pulmonary arterial hypertension (p < 0.001) than those without. In the AECA positive group, mean IgG-AECA levels (measured by absorbance values) were significantly higher in patients with digital infarcts (0.91+/-0.31 vs 0.60+/-0.05; p < 0.01) and pulmonary arterial hypertension (1.14+/-0.37 vs 0.68+/-0.13; p < 0.001) compared to those without these features.

CONCLUSION

IgG-AECA appears to be an important marker for disease severity in scleroderma.

Genotoxicity testing of two red dyes in the somatic and germ line cells of Drosophila

Two red dyes, rhodamine B and amaranth, were tested for their genotoxic effects in the somatic (wing primordia) and germ line cells of Drosophila melanogaster following the wing spot and the sex-linked recessive lethal tests. Second- and third-instar larvae, carrying suitable genetic markers, were subjected to chronic exposure to different concentrations of the test dyes. The results indicate that rhodamine is genotoxic in both somatic and germ line cells and amaranth is non-genotoxic.

Genotoxicity of 2,4-dichlorophenoxyacetic acid tested in somatic and germ-line cells of Drosophila

The genotoxic potential of 2,4-dichlorophenoxyacetic acid, a commonly used chlorophenoxy herbicide, was tested in Drosophila somatic and germ-line cells following the protocols of the wing spot test and the sex-linked recessive lethal test. In the wing spot test second- and third-instar larvae, carrying genetic markers mwh and flr3, were exposed to different concentrations of the herbicide so that induced genetic changes would be phenotypically expressed as mosaic spots on the wings of eclosing adults. The Basc (Muller-5) standard technique but with larval exposure was followed for the sex-linked recessive lethal test. The results obtained indicate that the test compound is genotoxic both in the somatic and germ-line cells of Drosophila.

Farm-grade chlorpyrifos (Durmet) is genotoxic in somatic and germ-line cells of Drosophila

The mutagenic potential of Durmet, a farm-grade formulation of chlorpyrifos, was studied in the Drosophila wing mosaic and sex-linked recessive lethal tests. Larvae of the 2nd or 3rd instar carrying suitable recessive genetic markers on chromosome 3 were exposed to different concentrations of the insecticide and the frequency of induction of mutant mosaic spots on the wings was noted. The Basc technique was followed to study the induction of sex-linked recessive lethals. On the basis of the frequency of induction of mosaic wing spots and sex-linked recessive lethals, it is concluded that Durmet is genotoxic in somatic cells as well as germ cells of Drosophila.

Studies on the genotoxicity of monocrotophos in somatic and germ-line cells of drosophila

Parryfos, a farm-grade formulation of monocrotophos, was tested for genotoxicity in the wing primordial cells and the male germ-line cells of Drosophila melanogaster. Larvae of the 2nd or 3rd instar, heterozygous for the wing-cell marker mutations mwh and flr3, were exposed to different concentrations of the insecticide in the food. The wings of the hatched flies were screened for the presence of mutant mosaic spots exhibiting the marker phenotypes. The frequency of induction of sex-linked recessive lethal mutations was used to assess genotoxic effects in male germ-line cells. The tested compound was genotoxic in both the somatic and the germ-line cells of Drosophila.

Mutagenicity of sumithion tested in Drosophila somatic and germ cells

Sumithion, a broad-spectrum insecticide, was tested for its mutagenicity in the Drosophila wing-spot test and sex-linked recessive lethal test. Strains carrying the recessive mutant markers mwh and flr3 in their third chromosomes, expressed phenotypically as multiple trichomes or thickened and misshapen wing hairs in the adult wings, were used in the wing-spot test. Larvae transheterozygous for these markers were exposed to the insecticide in instant food and the sex-linked recessive lethal test was performed by the standard technique using the Basc strain. The compound is mutagenic in the wing primordial cells and induces recombination at high doses. Further, the frequency of induction of sex-linked recessive lethals is significant only at high treatment doses.

Acrylamide is genotoxic to the somatic and germ cells of Drosophila melanogaster

The genotoxic effects of acrylamide, a recently detected carcinogen, have been studied in the somatic (wing primordia) and germ cells of Drosophila melanogaster by the wing mosaic assay and the sex-linked recessive lethal test respectively. Larvae, 72 +/- 4 h old, were exposed to 6 different concentrations of acrylamide ranging between 0.25 mM and 5.0 mM in instant medium for 48 h. It is observed that acrylamide is both mutagenic and recombinogenic in the wing disc cells and induces sex-linked recessive lethals.

Genetic toxicity of six carcinogens and six non-carcinogens in the Drosophila wing spot test

Six rodent carcinogens, 5 of which are also human carcinogens, and 6 compounds recognized as non-carcinogens were tested for their genotoxic activity in the Drosophila melanogaster wing spot test. 72-h-old larvae trans-heterozygous for the recessive wing cell markers 'multiple wing hairs' (mwh) and 'flare' (flr3) were fed various concentrations of the test compounds for a period of 48 h. With amitrole and 4-aminobiphenyl, larvae of the same age were also given an acute treatment of 6 h with higher concentrations, and, in addition, 48-h-old larvae were fed for a longer period of 72 h. Repeats of all experiments document the good reproducibility of the results in the wing spot test. Amitrole and 4-aminobiphenyl were genotoxic after both 48-h and 72-h treatments, but their activity could not be detected following acute exposure of only 6 h. Chlorambucil and melphalan were clearly genotoxic. The carcinogens sodium arsenite and sodium arsenate, however, which are highly toxic to Drosophila, could only be tested at low exposure levels and were negative under these treatment conditions. The 6 non-carcinogens (ascorbic acid, 2-aminobiphenyl, mannitol, piperonyl butoxide, stannous chloride and titanium dioxide) were all definitely non-genotoxic in the Drosophila wing spot test. The data for the non-carcinogens demonstrate that non-genotoxic compounds can be identified in the wing spot test with a reasonable experimental effort.

Genotoxicity of ziram established through wing, eye and female germ-line mosaic assays and the sex-linked recessive lethal test in Drosophila melanogaster

The genotoxicity of ziram (zinc-dimethyl dithiocarbamate, CAS No. 137-30-4), a carbamate fungicide, is studied in the wing, eye and female germ-line mosaic assays and the sex-linked recessive lethal test in Drosophila melanogaster. First-, second- and third-instar larvae, carrying suitable recessive genetic markers on their first and third chromosomes, were exposed to ziram. Wings and eyes of adults were screened for the induction of mosaic spots and the eggs laid by adult females for germ-line mosaicism. The Basc method was used to detect sex-linked recessive lethals. Ziram is genotoxic to the somatic and germ cells of Drosophila melanogaster.

Genotoxicity of Rogor studied in the sex-linked recessive lethal test and wing, eye and female germ-line mosaic assays in Drosophila melanogaster

The genotoxic potential of Rogor (dimethoate), an anticholinesterase organophosphate insecticide, has been studied in the sex-linked recessive lethal test and the wing, eye and female germ-line mosaic assays in Drosophila melanogaster. Larvae of different instars carrying suitable recessive genetic markers on their first and third chromosomes were exposed to the LD50 or half of this dose for the entire larval life. The Basc technique was followed for the detection of the induction of sex-linked recessive lethals. The wings and eyes of the adult flies and the eggs laid by the heterozygous females were checked for the induction of mosaicism. It is concluded that Rogor induces sex-linked recessive lethals in immature male germ cells and is recombinogenic and/or mutagenic in both the somatic and the germ-line cells of Drosophila.

Genotoxicity of zineb detected through the somatic and germ-line mosaic assays and the sex-linked recessive-lethal test in Drosophila melanogaster

The genotoxicity of zineb, a carbamate fungicide, has been tested through eye, wing and female germ line mosaic assays and the sex-linked recessive-lethal test in Drosophila melanogaster. Larvae of different instars, heterozygous for appropriate recessive genetic markers, were exposed to the fungicide in food for different durations of time. The adult eyes and wings were screened for induction of mosaic spots and the eggs laid by the females were checked for induction of female germ-line mosaicism. It is concluded that zineb is genotoxic to both somatic and germ-line cells of Drosophila.

Mutagenicity of dimecron studied in 3 mosaic assays and the sex-linked recessive lethal test in Drosophila melanogaster

The genotoxicity of dimecron, a systemic organophosphate pesticide, has been tested in the wing, eye and germ line mosaic assays and the sex-linked recessive lethal test in Drosophila melanogaster. Larvae heterozygous for recessive marker mutations were fed the compound for various periods of time. On emergence, the wings and eyes of the adults were screened for mosaic spots and the eggs laid by the females were checked for induction of female germ line mosaicism. Dimecron is mutagenic to the somatic and germ line cells of Drosophila and induces a high frequency of sex-linked recessive lethals.

Genotoxicity of metacid established through the somatic and germ line mosaic assays and the sex-linked recessive lethal test in Drosophila

The mutagenic potential of metacid (methyl parathion), an anticholinesterase organophosphate pesticide, has been studied in the Drosophila eye, wing and female germ line assays and the sex-linked recessive lethal tests. Larvae 24 h, 48 h and 72 h old, heterozygous for various recessive genetic markers on the first and third chromosomes, were exposed to the LD50 and half of this dose for different periods of time. The eyes and wings were checked for the presence of mosaic spots and eggs laid by the females for germ line mosaicism. The M-5 technique was used to detect the induction of sex-linked recessive lethals. It is concluded that metacid is mutagenic in somatic and germ line cells of Drosophila and induces sex-linked recessive lethals in immature male germ cells.

Green pupa (gp), a male lethal in culex quinquefasciatus

An autosomal recessive mutant, green pupa (gp), in Culex quinquefasciatus has been isolated. The homozygous (gp/gp) females are viable whereas male homozygotes do not develop beyond the pupal stage. The behavior of this mutant character in pedigree studies has been reported.