Prompt diagnosis of Scedosporium apiospermum soft tissue infection: Life-saving in a renal transplant recipient.

Scedosporium apiospermum, an ubiquitous filamentous fungus, a known cause of mycetoma, is emerging as an opportunistic pathogen in immunocompromised individuals. We report a case of painful foot abscess in a renal allograft recipient on immunosuppressive therapy, which was clinically diagnosed as a suppurative bacterial abscess. Pus was aspirated, which showed septate, branching hyphal elements and culture on Sabouraud's dextrose agar yielded S. apiospermum, which was identified based on its macroscopic and microscopic features. There are very few reports of scedosporiasis from India. High index of suspicion for unusual fungal infection helps in prompt etiological diagnosis in a transplant recipient and rapid management prevents further dissemination.

Evaluation of the role of substrate and albumin on Pseudomonas aeruginosa biofilm morphology through FESEM and FTIR studies on polymeric biomaterials.

Bacterial biofilms pose the greatest challenge to implant surgeries leading to device-related infections and implant failure. Our present study aims at monitoring the variation in the biofilm architecture of a clinically isolated strain and ATCC 27853 strain of Pseudomonas aeruginosa on two polymeric biomaterials, used in implants. The perspective of our study is to recognize the potential of these two biomaterials to create biofilm infections and develop the understanding regarding their limitations of use and handle patients with this deeper insight. The final goal, however, is an accurate interpretation of substrate-microbe interactions in the two biomaterials, which will provide us the knowledge of possible surface modifications to develop of an efficacious anti-biofilm therapy for deterring implant infections. The reference strain ATCC 27853 and a clinical isolate of P. aeruginosa collected from urinary catheters of patients suffering from urinary tract infections, have been used as microbes while clinical grades of polypropylene and high density polyethylene, have been used as 'substrates' for biofilm growth. The variation in the nature of the 'substrate' and 'conditioning layer' of BSA have been found to affect the biofilm architecture as well as the physiology of the biofilm-forming bacteria, accompanied by an alteration in the nature and volume of EPS (extracellular polysaccharide) matrices.

Use of an Innovative Simple Method for Anaerobiosis in the Diagnosis and Management of Infections in Two Unusual Cases.

Technical limitations restrict routine anaerobe isolation from clinical materials in resource-limited laboratories. An innovative two steps combustion candle jar technique may be suitable for such setup. This system was tried with one case of chronic osteomyelitis developed on supracondyler compound fracture. Porphyromonas spp. was isolated and identified. Vancomycin was recommended based on in vitro sensitivity test, but the leg was amputed after receiving a resistant drug gentamycin. While in another child with hydrocephalous, V-P shunt associated infection by Peptostreptococcus anaerobius was successfully controlled by sensitive drug vancomycin. These two eye-opener cases insisted us for large scale application of the technique.

Anaerobic culture on growth efficient bi-layered culture plate in a modified candle jar using a rapid and slow combustion system.

Success for maximum isolation of anaerobes depends on maintaining critically low oxygen levels throughout and growth in a reduced medium with exclusion of inhibitory substances. Hence a dual system was used equipped with candle combustion for instant exhaustion of major part of oxygen from a sealed jar, along with acidified steel wool for residual oxygen purging. For inhibitory substances removal, test anaerobes were grown on anaerobic medium layered on buffer charcoal agar bed. After 48 hours incubation average colony sizes were compared with that of growths in conventional Gas-Pak system. Better growths were noted in the innovative system.

SEMEDS: an important tool for air pollution bio-monitoring.

Plant canopies act as absorbers of air-borne dust particles. Characterization of the dusts present over the leaf surfaces can indicate the nature of contaminant present in the surrounding area and possible sources as well. Dust particulates get adsorbed on both the surfaces of leaves, however more dust particulates get deposited on the upper surface. These dusts contain many inorganic elements, which were analyzed in the present study. For the present investigation, SEMEDS technique used to characterize the dusts adsorbed over the leaf surfaces. Using SEMEDS the samples were analyzed by two types of methods i.e. point analysis and elemental mapping. Both the methods showed the presence of elements like Si, Al, Fe, Mg, and Ca in the dusts adsorbed over the leaf surfaces. Thus, SEMEDS can be used for in situ air pollution monitoring using tree leaves from the area concerned.

Interaction of single-walled carbon nanotubes with poly(propyl ether imine) dendrimers.

We study the complexation of nontoxic, native poly(propyl ether imine) dendrimers with single-walled carbon nanotubes (SWNTs). The interaction was monitored by measuring the quenching of inherent fluorescence of the dendrimer. The dendrimer-nanotube binding also resulted in the increased electrical resistance of the hole doped SWNT, due to charge-transfer interaction between dendrimer and nanotube. This charge-transfer interaction was further corroborated by observing a shift in frequency of the tangential Raman modes of SWNT. We also report the effect of acidic and neutral pH conditions on the binding affinities. Experimental studies were supplemented by all atom molecular dynamics simulations to provide a microscopic picture of the dendrimer-nanotube complex. The complexation was achieved through charge transfer and hydrophobic interactions, aided by multitude of oxygen, nitrogen, and n-propyl moieties of the dendrimer.

Avian- and mammalian-derived antibodies against adherence-associated proteins inhibit host cell colonization by Escherichia coli O157:H7.

AIM: To evaluate the potential for polyclonal antibodies targeting enterohaemorrhagic Escherichia coli (EHEC) virulence determinants to prevent colonization of host cells by E. coli O157:H7. METHODS AND RESULTS: Rats and laying hens were immunized with recombinant proteins from E. coli O157:H7, EspA, C-terminal intimin or EscF. Rat antisera (IgG) or chicken egg powders (IgY) were assessed for their ability to inhibit growth and colonization-associated processes of E. coli O157:H7. Mammalian antisera with antibodies to intimin, EspA or EscF effectively reduced adherence of the pathogen to HeLa cells (P<0.05) and prevented type III secretion of Tir. Similarly, HeLa cells treated with chicken egg powder containing antibodies against intimin or EspA were protected from EHEC adherence (P<0.05). Neither egg nor rat antibody preparations had any antibacterial effect on the growth of EHEC (P>0.05). CONCLUSIONS: Antibody preparations targeting EHEC adherence-associated factors were effective at preventing adhesion and intimate colonization-associated events. SIGNIFICANCE AND IMPACT OF THE STUDY: This work indicates that immunotherapy with anti-adherence antibodies can reduce E. coli O157:H7 colonization of host cells. Passive immunization with specific antibodies may have the potential to reduce E. coli O157:H7 colonization in hosts such as cattle or humans.

Mycetoma caused by a new red grain mycetoma agent in two members of a family.

An 18-year-old woman from rural West Bengal was affected with mycetoma involving her neck, back, and chest. After an interval of eight years, her younger brother developed mycetoma on his left arm. No history of trauma or immune deficiency was present in either case. By microscopic examination of sinus-discharged materials from both the cases, identical rusty red, hard grains were demonstrated. Soluble red pigment-producing colonies grew in Sabouraud dextrose-agar medium. Isolates were positive for casein hydrolysis and negative for hydrolysis test of xanthine, hypoxanthine, tyrosine, and nitrate reduction. Thus it differed from the only known red grain mycetoma agent, Actinomadura pelletieri and was provisionally identified as Actinomadura vinacea. Familial affection in mycetoma, that too caused by a new agent, is reported here for its uniqueness.

Epidemiological aspects of mycetoma from a retrospective study of 264 cases in West Bengal.

Between 1981 and 2000, 264 cases of mycetoma were diagnosed clinically and microbiologically at Calcutta School of Tropical Medicine. Retrospective analysis of the records revealed that the ratio of actinomycetomas and eumycetomas was 197 : 67; the male to female ratio was 183 : 81. Ninety-four cases occurred in the 1980s and 170 in 1990s, with significantly more infections of Actinomadura spp. (P < 0.01) and fewer with Nocardia caviae (P < 0.01) during the last decade. Pricking was the most common injury associated with eumycetomas (P < 0.01). A total of 196 infections were in exposed body parts and 68 in covered areas. The localization of mycetomas differed significantly (P < 0.01) according to sex, incidence of actinomycetomas or eumycetomas, and obvious history of trauma. Exposed area cases were more common among agricultural workers (P < 0.01), while covered area mycetomas were almost always actinomycetomas with a remarkably lower incidence of N. caviae, A. madurae and Madurella grisea infections. The peak age of onset was between 16 and 25 years. The delay of diagnosis for the 80th percentile of cases was around 6 years for cases caused by N. brasiliensis and Streptomyces spp.; 8 years for N. caviae and N. asteroides; and 10 years for M. grisea and Actinomadura spp. From the history of trauma in 130 patients, the 80th percentile incubation period (IP) was calculated for N. brasiliensis, N. caviae and N. asteroides as 3 years; for Actinomadura spp. 7 years and for M. grisea 9 years. The minimum IP for all organisms was around 3 months.

Suppression of experimental myasthenia gravis, a B cell-mediated autoimmune disease, by blockade of IL-18.

Interleukin-18 (IL-18) is a pleiotropic proinflammatory cytokine that plays an important role in interferon gamma (IFN-gamma) production and IL-12-driven Th1 phenotype polarization. Increased expression of IL-18 has been observed in several autoimmune diseases. In this study we have analyzed the role of IL-18 in an antibody-mediated autoimmune disease and elucidated the mechanisms involved in disease suppression mediated by blockade of IL-18, using experimental autoimmune myasthenia gravis (EAMG) as a model. EAMG is a T cell-regulated, antibody-mediated autoimmune disease in which the nicotinic acetylcholine receptor (AChR) is the major autoantigen. Th1- and Th2-type responses are both implicated in EAMG development. We show that treatment by anti-IL-18 during ongoing EAMG suppresses disease progression. The protective effect can be adoptively transferred to naive recipients and is mediated by increased levels of the immunosuppressive Th3-type cytokine TGF-beta and decreased AChR-specific Th1-type cellular responses. Suppression of EAMG is accompanied by down-regulation of the costimulatory factor CD40L and up-regulation of CTLA-4, a key negative immunomodulator. Our results suggest that IL-18 blockade may potentially be applied for immunointervention in myasthenia gravis.

Rapid imaging of human melanoma xenografts using an scFv fragment of the human monoclonal antibody H11 labelled with 111In.

H11 is a human IgM monoclonal antibody which recognizes a novel tumour-associated antigen expressed on melanoma, glioma, breast cancer, colon cancer, prostate cancer, lung cancer and B-cell lymphoma. In this study, a recombinant single-chain Fv (scFv) fragment of H11 labelled with 111In was investigated for tumour imaging in athymic mice implanted subcutaneously with A-375 human melanoma xenografts. H11 scFv was derivatized with diethylenetriaminepentaacetic acid (DTPA) for labelling with 111In. The immunoreactivity of DTPA-H11 scFv against A-375 cells in vitro ranged from 23% to 36%. 111In-DTPA-H11 scFv was rapidly eliminated from the blood and most normal tissues (except the kidneys) reaching maximum tumour/blood ratios of 12:1 at 48 h post-injection. Tumours were imaged as early as 40 min after injection. The kidneys accumulated the highest concentration of radioactivity (up to 185% injected dose/g). Tumour uptake was 1-3% injected dose/g. The whole-body radiation absorbed dose predicted for administration of 185 MBq of 111In-DTPA-H11 scFv to humans was 37 mSv. The radiation absorbed dose estimates for the kidneys, spleen and intestines were 405 mSv, 698 mSv and 412 mSv, respectively. The results of this preclinical study and a concurrent phase I trial suggest a promising role for H11 scFv for tumour imaging.

Blockade of CD40 ligand suppresses chronic experimental myasthenia gravis by down-regulation of Th1 differentiation and up-regulation of CTLA-4.

Myasthenia gravis (MG) and experimental autoimmune MG (EAMG) are T cell-dependent Ab-mediated autoimmune disorders, in which the nicotinic acetylcholine receptor (AChR) is the major autoantigen. Th1-type cells and costimulatory factors such as CD40 ligand (CD40L) contribute to disease pathogenesis by producing proinflammatory cytokines and by activating autoreactive B cells. In this study we demonstrate the capacity of CD40L blockade to modulate EAMG, and analyze the mechanism underlying this disease suppression. Anti-CD40L Abs given to rats at the chronic stage of EAMG suppress the clinical progression of the autoimmune process and lead to a decrease in the AChR-specific humoral response and delayed-type hypersensitivity. The cytokine profile of treated rats suggests that the underlying mechanism involves down-regulation of AChR-specific Th1-regulated responses with no significant effect on Th2- and Th3-regulated AChR-specific responses. EAMG suppression is also accompanied by a significant up-regulation of CTLA-4, whereas a series of costimulatory factors remain unchanged. Adoptive transfer of splenocytes from anti-CD40L-treated rats does not protect recipient rats against subsequently induced EAMG. Thus it seems that the suppressed progression of chronic EAMG by anti-CD40L treatment does not induce a switch from Th1 to Th2/Th3 regulation of the AChR-specific immune response and does not induce generation of regulatory cells. The ability of anti-CD40L treatment to suppress ongoing chronic EAMG suggests that blockade of CD40L may serve as a potential approach for the immunotherapy of MG and other Ab-mediated autoimmune diseases.

In vitro susceptibility pattern of Sporothrix schenckii strains isolated from three centers in India.

BACKGROUND & OBJECTIVES: With the availability of more number of antifungal agents in recent years, drugs other than saturated solution of potassium iodide (SSKI) are being increasingly used to treat sporotrichosis. It was therefore considered pertinent to evaluate in vitro antifungal susceptibility pattern of Sporothrix schenckii strains isolated at three centers in India against five commonly used antifungal agents. METHODS: Agar dilution method was used to evaluate 50 clinical isolates (25 from north, 17 from east and 8 from south India) both in its yeast and mycelial forms against amphotericin-B, 5-fluorocytosine, ketoconazole, fluconazole and itraconazole. RESULTS: No resistance was observed in the yeast form of S. schenckii against amphotericin B and azoles. However, 54 per cent strains in the yeast form were resistant to 5-fluorocytosine. None of the strains was susceptible to amphotericin B and ketoconazole, 56 and 10 per cent strains in the mycelial form were susceptible to itraconazole and fluconazole respectively. No significant difference was observed in the antifungal susceptibility pattern among the strains isolated from these three regions in India. INTERPRETATION & CONCLUSION: Clinical isolates of S. schenckii from three regions of India had a more or less uniform antifungal susceptibility pattern. Itraconazole had the best in vitro susceptibility results against the clinical isolates of S. schenckii and has the potential to replace SSKI.

Histoplasmosis in eastern India: the tip of the iceberg?

Systemic histoplasmosis has various clinical presentations and is of especially concern in immunocompromised patients. A high index of suspicion is required for its diagnosis. A total of 38 cases had been reported from India up to 1996. The most frequent occurrence of cases was around Calcutta in eastern India where the previous case was detected 20 years earlier. However, we have diagnosed 5 cases in the past 2 years from eastern India which are reported here. These cases may indicate under-diagnosis and under-reporting of histoplasmosis in India. All 5 patients had disseminated disease with multisystem involvement including 2 with bilateral adrenal enlargement. Two were diabetic and only 1 patient was infected with HIV.

Possible involvement of lipid peroxidation in the inhibition of type I iodothyronine 5'-monodeiodinase activity by lead in chicken liver.

The possible involvement of lipid peroxidation (LPO) in the lead-induced inhibition of type I iodothyronine 5'-monodeiodinase activity (5'-D) has been worked out in chicken liver. Lead nitrate (1.5 mg per bird per day) for 30 days increased the lipid peroxidative process with a concomitant decrease in 5'-D activity in chicken liver. Also, a significant decrease in serum triiodothyronine (T3) concentration and an increase in serum thyroxine (T4) concentration were observed. The data suggest that lead-induced inhibition of type I 5'-D activity in chicken liver is mediated through the lipid peroxidative process.

Is triiodothyronine capable of ameliorating pyrethroid-induced thyroid dysfunction and lipid peroxidation?

A study on the effect of triiodothyronine (T3) in the regulation of pyrethroid (fenvalerate)-induced thyroid dysfunction and lipid peroxidation was carried out in male mice. Fenvalerate (120 mg kg(-1) body wt. daily for 15 days) administration led to a decrease in the serum concentration of thyroid hormones and the activity of hepatic type I iodothyronine 5'-monodeiodinase (5'D-I) and an increase in the level of lipid peroxidation. The decrease in the activity of hepatic 5'D-I due to the administration of fenvalerate was restored with the administration of T3 (7 microg kg[-1] body wt. on alternate days). The increased level of lipid peroxidation was also ameliorated by T3. However, T3 could not restore the serum concentration of thyroxine (T4), only that of T3. We suggest that the ameliorating role of T3 in the fenvalerate-intoxicated mice could be the result of the lipogenic action of the thyroid hormone, which in turn led to the restoration of 5'D-I activity.

Immunoreactivity of human MAb BT32/A6 with neuroepithelial tumors.

The present study was undertaken to determine the pattern of immunoreactivity of BT32/A6, a human IgM monoclonal antibody (MAb), with the following histological panels: 1) 30 human and non-human cell lines, 2) 32 normal human tissues, and 3) 28 tumors of central neuroepithelial origin (16 astrocytic; 11 non-astrocytic). Antibody BT32/A6 recognizes a surface and cytoplasmic antigen present on a variety of human tumor cell lines including gliomas, melanomas, neuroblastomas, and a few sarcomas. The antigen is present (at least focally) on 15/16 astrocytic tumor tissue sections (94%), and in some cases, on close to 100% of cells. All malignant cell types, including small anaplastic cells, giant cells, gemistocytic cells, and cells forming pseudopalisades were labeled by MAb BT32/A6. Non-astrocytic neuroepithelial tumors did not stain appreciably with MAb BT32/A6. There was weak immunoreactivity in a small subset of normal human tissues of epithelial and lymphoid origin, with the exception of adrenal cortex, which exhibited weak to moderate staining. All normal tissues of neuroectodermal and mesenchymal origin were unreactive. In conclusion, MAb BT32/A6 appears to be unique in that it recognizes a highly-expressed astrocytic tumor-associated antigen that is present on both low and high grade tumors. This makes it a strong candidate for further studies aimed at establishing its usefulness in the treatment of human astrocytic tumors.

Sexual risk factors for cervical cancer among rural Indian women: a case-control study.

BACKGROUND: The association between sexual behaviour and cervical cancer is well established. Despite a high incidence of cervical cancer in India, its role has not been widely investigated in Indian women among whom the rate of sexual promiscuity is known to be very low. A hospital-based case-control study was carried out to investigate the role of sexual risk factors in cervical cancer among rural Indian women. METHODS: A case-control design was used in which a total of 268 subjects, comprising 134 women with invasive cervical cancer as cases and 134 control women were studied. A multiple logistic regression model was used to analyse the data. RESULTS: The risk factors found to be associated with cervical cancer were early age at first coitus, extramarital sex partners of women and the time interval since first exposure. In a multiple logistic regression model, independent effects were observed for early age at first coitus, showing maximum risk in women who reported their first intercourse at < 12 years of age, compared to that of women at > or = 18 years (odds ratio [OR] = 3.5. 95% confidence interval [CI]: 1.1-10.9). Increased risk was also seen for women who had extramarital sex relationships (OR = 5.5, 95% CI: 1.5-19.5). The significant effect of early age at first coitus persisted after adjustment for latency period which also showed its independent risk association with cervical cancer in the multivariate analysis. CONCLUSION: These findings confirm the association between early age at first coitus and cervical cancer in women with a low rate of sexual promiscuity and define the role of these risk factors in cervical carcinogenesis among rural Indian women.

PIP: The association between sex behavior and cervical cancer was investigated among rural Indian women known to have very low levels of promiscuity. 134 women with invasive cervical cancer were matched with 134 controls and analysis performed using a multiple logistic regression model. Risk factors associated with cervical cancer were early age at first coitus, extramarital sex partners of women, and the time interval since first exposure. Independent effects were observed for early age at first coitus, with maximum risk among women who reported their first intercourse at younger than age 12 years compared to that of women at age 18 years or older. Increased risk was also seen for women who had extramarital sex relationships. The significant effect of early age at first coitus persisted after adjustment for a latency period which also showed its independent risk association with cervical cancer in the multivariate analysis.