Siderophore-dependent ferrichelatases.

Iron is a crucial secondary metabolite for bacterial proliferation, but its bioavailability under infection conditions is limited by the low solubility of ferric ion and the host's ability to sequester iron by protein chelation. In these iron limiting conditions, bacteria produce and secrete low molecular weight ferric ion chelators, siderophores, to scavenge host iron. Iron bound siderophores are recognized by surface displayed receptors and internalized by active transport preceding the liberation of the iron payload by reduction or cleavage of the siderophore. The traditional paradigms surrounding the interactions between siderophores and their corresponding receptors have relied on canonical protein-ligand binding models that do not accurately reflect the conditions experienced by siderophore binding proteins (SBPs). Research by the Raymond group suggested that a ligand displacement model does not fully describe the role of SBPs in siderophore transport where the ferric ion can be shuttled between siderophore molecules during the transport process. This work inspired further research by the Wencewicz group, which demonstrated that the Staphylococcus aureus SBP FhuD2 can catalyze the transfer of iron from the biological iron source holo-transferrin to a SBP bound iron-free siderophore. The discovery of this ferrichelatase activity represents a novel mechanism of receptor mediated active transport which raises the question: is ferrichelatase activity a unique feature of FhuD2 or a previously unappreciated hallmark of SBPs? This chapter highlights a series of protocols for the general functional characterization of SBPs and methodologies to assay ferrichelatase activity with the hopes of providing the tools to answer this question.

Neuroimaging in Pediatric Patients with Juvenile Xanthogranuloma of the CNS.

BACKGROUND AND PURPOSE: Juvenile xanthogranuloma is a rare clonal, myeloid, neoplastic disorder. Typically, juvenile xanthogranuloma is a self-limited disorder of infancy, often presenting as a solitary red-brown or yellow skin papule/nodule. A small subset of patients present with extracutaneous, systemic juvenile xanthogranuloma, which may include the CNS. The goal of this retrospective study was to evaluate and categorize the neuroimaging findings in a representative cohort of pediatric patients with CNS juvenile xanthogranuloma. MATERIALS AND METHODS: The brain and/or spine MR imaging data of 14 pediatric patients with pathology-proven juvenile xanthogranuloma were categorized and evaluated for the location; the signal intensity of xanthogranulomas on T1WI, T2WI, DWI, and a matching ADC map for the pattern and degree of contrast enhancement; and the presence of perilesional edema, cysts, or necrosis. RESULTS: Fourteen pediatric patients (8 girls, 6 boys; mean age, 84 months) were included in the study. Patients presented with a wide variety of different symptoms, including headache, seizure, ataxia, strabismus, hearing loss, facial paresis, and diabetes insipidus. Juvenile xanthogranuloma lesions were identified in a number of different sites, including supra- and infratentorial as well as intracranial and spinal leptomeningeal. Five patients were categorized into the neuroradiologic pattern unifocal CNS juvenile xanthogranuloma; 8, into multifocal CNS juvenile xanthogranuloma; and 1, into multifocal CNS juvenile xanthogranuloma with intracranial and spinal leptomeningeal disease. In most cases, xanthogranulomas were small-to-medium intra-axial masses with isointense signal on T1WI (compared with cortical GM), iso- or hyperintense signal on T2WI, had restricted diffusion and perilesional edema. Almost all xanthogranulomas showed avid contrast enhancement. However, we also identified less common patterns with large lesions, nonenhancing lesions, or leptomeningeal disease. Four cases had an additional CT available. On CT, all xanthogranulomas were homogeneously hyperdense (solid component) without evident calcifications. CONCLUSIONS: CNS juvenile xanthogranuloma may demonstrate heterogeneous neuroimaging appearances potentially mimicking other diseases, such as primary brain neoplasms, metastatic disease, lymphoma and leukemia, other histiocytic disorders, infections, or granulomatous diseases.

Cause of intrauterine and neonatal death in twin pregnancies (CoDiT): development of a novel classification system.

OBJECTIVE: Twin pregnancies have a significantly higher perinatal mortality than singleton pregnancies. Current classification systems for perinatal death lack twin-specific categories, potentially leading to loss of important information regarding cause of death. We introduce and test a classification system designed to assign a cause of death in twin pregnancies (CoDiT). DESIGN: Retrospective cross-sectional study. SETTING: Tertiary maternity unit in England with a perinatal pathology service. POPULATION: Twin pregnancies in the West Midlands affected by fetal or neonatal demise of one or both twins between 1 January 2005 and 31 December 2016 in which postmortem examination was undertaken. METHODS: A multidisciplinary panel designed CoDiT by adapting the most appropriate elements of singleton classification systems. The system was tested by assigning cause of death in 265 fetal and neonatal deaths from 144 twin pregnancies. Cause of death was validated by another obstetrician blinded to the original classification. MAIN OUTCOME MEASURES: Inter-rater, intra-rater, inter-disciplinary agreement and cause of death. RESULTS: Cohen's Kappa demonstrated 'strong' (>0.8) inter-rater, intra-rater and inter-disciplinary agreement (95% CI 0.70-0.91). The commonest cause of death irrespective of chorionicity was the placenta; twin-to-twin transfusion syndrome (TTTS) was the commonest placental cause in monochorionic twins and acute chorioamnionitis in dichorionic twins. CONCLUSIONS: This novel classification system records causes of death in twin pregnancies from postmortem reports with high inter-user agreement. We highlight differences in aetiology of death between monochorionic and dichorionic twins. TWEETABLE ABSTRACT: New classification system for #twin cause of death 'CoDiT' shows high rater agreement.

Perceptions of Insulin Pen Use and Technique in Black and Hispanic/Latino Patients with Type 2 Diabetes: a Qualitative Study.

OBJECTIVES: Non-Hispanic Blacks (NHB) and Hispanic/Latinos (H/L) are affected disproportionately by type 2 diabetes (T2DM) and its complications due to a myriad of reasons. Lack of diabetes education has been identified as one risk factor for poorly controlled diabetes. For persons using insulin, poor insulin administration technique can be problematic. Previous studies done demonstrating this have not been inclusive of NHB and H/L populations. As a result, this study aimed to use semi-structured interviews to examine insulin pen technique and training experience in NHB and H/L inpatients with T2DM. DESIGN: Semi-structured interviews comprised open- and close-ended questions, and prompts were conducted until reaching saturation in NHB and H/L inpatients with at least 3 months of insulin pen use. Data was analyzed by two researchers who completed a thematic analysis. RESULTS: Twenty semi-structured interviews were completed. Two major themes emerged from analysis included: patients prefer the insulin pen to syringes and vials and most had a lack of formal pen technique teaching. CONCLUSION: Although the insulin pen is a preferred modality of insulin delivery, this sampling of disparity patients demonstrates that insulin pen technique should be continually reassessed by health care providers as majority of the patients never had formal insulin pen teaching. Among those who did have training, they still made errors such as not priming the pen or shortened dwell time.

The in vivo fates of plant viral nanoparticles camouflaged using self-proteins: overcoming immune recognition.

Nanoparticles offer a promising avenue for targeted delivery of therapies. To slow clearance, nanoparticles are frequently stealth-coated to prevent opsonization and immune recognition. Serum albumin (SA) has been used as a bio-inspired stealth coating. To develop this shielding strategy for clinical applications, it is critical to understand the interactions between the immune system and SA-camouflaged nanoparticles. This work investigates the in vivo processing of SA-coated nanoparticles using tobacco mosaic virus (TMV) as a model system. In comparing four different SA-formulations, the particles with high SA coverage conjugated to TMV via a short linker performed the best at preventing antibody recognition. Irrelevant of the coating chemistry, all formulations led to similar levels of TMV-specific antibodies after repeat administration in mice; importantly though, SA-specific antibodies were not detected and the TMV-specific antibodies were unable to recognize shielded SA-coated TMV. Upon uptake in macrophages, the shielding agent and nanoparticle separate, where TMV trafficked to the lysosome and SA appears to recycle. The distinct intracellular fates of the TMV carrier and SA shielding agent explain why anti-TMV but not SA-specific antibodies are generated. This work characterizes the outcomes of SA-camouflaged TMV after immune recognition, and highlights the effectiveness of SA as a nanoparticle shielding agent.

A rare case of phaeohyphomycosis caused by Fonsecaea pedrosoi in a child with nephrotic syndrome.

Dematiaceous fungi are the etiological agents of phaeohyphomycosis and are now increasingly being recognized for causing disease in humans. A high level of suspicion and routine fungal cultures are required to identify these cases. There is no consensus regarding their management. Here, an unusual presentation of phaeohyphomycosis (secondary to Fonsecaea pedrosoi) presenting as a disseminated infection in a case of nephrotic syndrome is described.

Differential binding and internalization of Clostridium difficile toxin A by human peripheral blood monocytes, neutrophils and lymphocytes.

Colitis due to Clostridium difficile infection is mediated by secreted toxins A and B and is characterized by infiltration by cells from the systemic circulation. The aim of our study was to investigate interactions between fluorescently labelled toxin A and peripheral blood monocytes, neutrophils and lymphocytes. Purified toxin A was labelled with Alexa Fluor® 488 (toxin A(488)) and incubated with isolated human peripheral blood mononuclear cells or washed whole blood cells for varying time intervals at either 37 or 4 °C/ice. The ability of trypan blue to quench cell surface-associated (but not cytoplasmic) fluorescence was also investigated. At 37 °C, toxin A(488) -associated fluorescence in monocytes peaked at 1 h (majority internalized), with subsequent loss associated with cell death. In contrast to monocytes, binding of toxin A(488) in neutrophils was greater on ice than at 37 °C. Studies using trypan blue suggested that over 3 h at 37 °C, most of the toxin A(488)-associated fluorescence in neutrophils remained at the cell surface. Over 48 h (37 °C and ice/4 °C), there was minimal toxin A(488)-associated fluorescence in lymphocytes. These studies suggest major differences in interactions between toxin A and circulating cells that infiltrate the mucosa during colonic inflammation in C. difficile infection.

Sudden vision loss caused by rhino-orbital zygomycosis in diabetic patients: case series.

Rhino-orbital zygomycosis is a life-threatening fungal infection generally occurring in patients with an underlying disorder, such as diabetes mellitus with ketoacidosis or with immunocompromising factors, although it may rarely appear in healthy individuals. The study has been undertaken to discuss the clinical presentation, pathogenesis, diagnostic work up and management of this rapidly progressive disease. Four male patients having uncontrolled diabetes and presenting with signs and symptoms of rhino-orbital zygomycosis were studied to illustrate the serious nature of the disease. All the four patients had rapidly deteriorating vision loss either unilateral or bilateral along with other nasal and orbital signs and symptoms. All the patients were put on liposomal amphotericin B and underwent orbital exenteration and pansinusectomy. One patient died, while the other three were successfully treated. Early diagnosis is critical in the prevention of morbidity and mortality associated with the disease. There is need for a high index of clinical suspicion in immunocompromised patients. Timely medical-surgical treatment proves extremely important for prognosis.

Subcutaneous phaeohyphomycotic cyst caused by Pyrenochaeta romeroi.

Pyrenochaeta romeroi is a rare agent of chronic, suppurative subcutaneous infections which ultimately lead to mycetoma. It has only rarely been reported from deep, non-mycetomatous infections. We describe a case of a subcutaneous phaeohyphomycotic cyst in a 45-year-old Indian female who suffered from verrucous plaque and a swelling (30 mm in diameter) on the right forearm that gradually increased in size over a period of 3 months. Direct microscopic examination with 10% KOH and histopathological investigation of exudates revealed septate hyphae without granules, the hallmark of mycetoma. The lesion appeared to be a subcutaneous phaeohyphomycotic cyst caused by P. romeroi. The suspected agent was recovered in culture, identified on the basis of morphologic features and its identification confirmed by sequencing of the internal transcribed spacer regions of rDNA. Treatment consisted of surgical excising of the cyst without any antifungal therapy. There was no relapse during a one-year follow-up and the patient was successfully cured. In vitro antifungal susceptibility tests demonstrated that itraconazole (0.5 microg/ml), isavuconazole (0.125 microg/ml) and posaconazole (0.5 microg/ml) had potent activity against this isolate of P. romeroi. High MICs were found with amphotericin B (4 microg/ml), fluconazole (>64 microg/ ml), voriconazole (4 microg/ml) and caspofungin (8 microg/ml). However, their clinical effectiveness in the treatment of P. romeroi infections remains to be evaluated.

Testicular toxicity of chlorpyrifos (an organophosphate pesticide) in albino rat.

Organophosphates are among the most widely used synthetic insect pesticides. The widespread use of organophosphates has stimulated research into the possible existence of effects related with their reproductive toxic activity. Present study was therefore, undertaken to assess the effects of chlorpyrifos on testes, the main organ of male reproduction. Chlorpyrifos at the dose levels of 7.5, 12.5 and 17.5 mg/kg b. wt./day was administered orally to male rats of Wistar strain for 30 days to evaluate the toxic alterations in testicular histology, biochemistry, sperm dynamics and testosterone levels. The body weight of animals did not show any significant change, however, a significant reduction was observed in testes. Chlorpyrifos also brought about marked reduction in epididymal and testicular sperm counts in exposed males and a decrease in serum testosterone concentration. Histopathological examination of testes showed mild to severe degenerative changes in seminiferous tubules at various dose levels. Fertility test showed 85% negative results. A significant reduction in the sialic acid content of testes and testicular glycogen was noticed, whereas the protein and cholesterol content was raised at significant levels. All these toxic effects are moderate at low doses and become severe at higher dose levels. From the results of the present study it is concluded that chlorpyrifos induces severe testicular damage and results in reduction in sperm count and thus affect fertility. Small changes in sperm counts are known to have adverse affects on human fertility. Therefore, application of such insecticide should be limited to a designed programme.

The dispersion of natural oils in de-gassed water.

Recent studies have demonstrated that pure hydrocarbon oils can be dispersed in water as fine droplets without the use of additives. The high interfacial tension between hydrocarbons and water is expected to cause cavitation between oil droplets during separation. This cavitation is aided by dissolved atmospheric gases present in both the oil and water. Their removal allows oil droplets to be readily dispersed in water. In this paper we report on the effect of the de-gassing process on the dispersion of several natural, water immiscible oils. These natural, mixed oils are eucalyptus, lavender and tea tree oil. Although these oils are mixtures and in some cases not as hydrophobic as those used in the earlier studies, the effect of de-gassing substantially enhances their dispersion, producing micron-sized droplets without the need for additives. Dispersions of these natural oils in pure water have a wide range of uses where purity is an advantage, for example, in skin cleaning products and oral sprays.

A study of satisfaction with dental services among adults in the United Kingdom.

OBJECTIVES: To determine satisfaction with dental care services among the UK adult population, and to assess their knowledge regarding the dental complaints procedure. METHODS: A national survey involving a multi-stage random sampling procedure with face-to-face home interviews of 5,385 UK residents was conducted in 1999. RESULTS: The response rate was 69% and 3,739 adults took part in this study. Majority of people (89%) were satisfied with the quality of care they received. Only 2% (76) had actually complained, although 10% (388) had felt like complaining in the past. One third (32%, 1,188) did not know to whom to complain if they had a problem. Among those who knew whom to contact, over a third (36%, 1,359) would contact somebody outside the practice, while another third (31%, 1,169) would contact their dentist or dental practice. CONCLUSION: Overall most people are satisfied with the quality of dental care they receive. However, 2% have complained and 10% have felt like complaining about their dentist/ dental care. In general, knowledge of the complaints procedure and whom to contact appears fragmented.

Unusual presentation of lupus nephritis.

We report a male patient who presented with pyrexia, generalized lymphadenopathy, hepatosplenomegaly, and pleural effusion with no cutaneous or musculoskeletal symptoms. Despite extensive investigation, no cause was detected. His initial serology was also negative for autoantibodies. The patient was placed on a trial of antitubercular treatment in view of a positive Mantoux test. His disease evolved into the full clinical picture of systemic lupus erythematosus with nephritis (World Health Organisation class IV) and strongly positive antinuclear antibody and dsDNA over a period of months. He was treated successfully with intravenous cyclophosphamide pulses along with oral prednisolone, and the disease was still in remission after 3 years of follow-up.

Urodynamic profile after Wertheim's hysterectomy.

Wertheim 's hysterectomy is likely to cause damage to innervation and anatomical support of the lower urinary tract. Urodynamic assessment was done in twenty patients of histopathologically proven cancer cervix who were about to undergo Wertheim's hysterectomy. The study was performed preoperatively, in the immediate postoperative period and six weeks after surgery. Urodynamic study included uroflowmetry, cystometry and urethral pressure profile. Urinary symptoms were also corelated with the urodynamic profile. It was concluded that the bladder was hypertonic in the immediate postoperative period and urethral closure pressures were low. Some regeneration of damaged nerve fibres was found to occur during the 6-8 weeks after surgery resulting in some improvement in sensory and motor functions of the bladder Post operatively continuous catheter drainage appeared to be the most important part of management of hypertonic bladder and the duration was individualised on the basis of urodynamic investigations.

Superoxide anion formation and glutathione levels in patients with preeclampsia.

Increased free radical activity has been implicated in the pathogenesis of preeclampsia. This article investigates the glutathione status in preeclampsia and whether superoxide generation is enhanced in preeclampsia. Venous blood samples were obtained from 30 preeclamptic women and 30 normotensive pregnant women (controls). Superoxide generation and glutathione content were measured. There was a significant increase in superoxide generation and a marked reduction in glutathione content in preeclamptic women as compared to controls (p < 0.001). These results indicate that enhanced superoxide generation and impaired glutathione metabolism may be involved in the pathogenesis of preeclampsia.

AIDS-related apprehensions among nursing students of Delhi.

Students from a nursing school of Delhi were surveyed anonymously using a self-administered questionnaire to explore various AIDS-related apprehensions and their possible reasons. The observations revealed that, majority of the students and their families/friends feared that these students were at risk of contracting HIV infection while providing routine patient care. A large number of students also opined that they would feel uncomfortable while talking, hugging, shaking hands, and sharing a room with an HIV positive person. The main reasons for their apprehensions were unsatisfactory anti-AIDS campaigning by the government, non-availability of sufficient protective measures in the health care settings, inadequate professional education related to prevention of HIV infection, and increase in HIV transmission following false sense of security due to excessive condom promotion. Findings of the study imply imparting factual knowledge addressing the concerns and removing misconceptions which influence attitudes and willingness of the nursing students to provide care to the HIV positives/AIDS patients, facts regarding efficacy of various preventive measures, and provision of counselling services in the event of exposure.

Some AIDS-related policy issues and nursing students' willingness to provide AIDS care.

Two thirty three diploma students from a Nursing School, in Delhi were surveyed anonymously to seek their opinion on some AIDS-related policy issues and willingness to provide AIDS care. More than one fourth of students opinionated that health personnel should be given a choice to refuse care to the AIDS patients and an equal proportion felt that authorities should be empowered to terminate the services of such personnel. Majority were in favour of making HIV testing compulsory for various high risk groups, indoor patients and health workers. Perceiving the risk of HIV infection, 41.2% students felt that girls might not opt for nursing career, whereas few (10.7%) were considering even to leave the profession. However, majority (58-72%) were willing to nurse the high risk individuals, if adequate training and preventive measures were provided in the health care settings. The study implies framing of an AIDS policy taking in to consideration the views of health professionals and imparting comprehensive training to the nursing students in order to promote a humane approach towards AIDS care.

PIP: By 2000, 1 out of every 6 HIV-infected people in the world will be in India. While the extent of HIV seroconversion following occupational exposure is reported to be very low, HIV continues to be a major concern among health care workers. 233 female diploma students aged 17-23 years from a nursing school in Delhi were surveyed anonymously to seek their opinion on certain AIDS-related policy issues and their willingness to care for people with AIDS. More than 25% of the students believed that health personnel should be allowed to choose whether or not to provide care to people with AIDS, while an equal percentage felt that authorities should be empowered to terminate the services of such personnel. 64-85% of the respondents favored compulsory HIV testing for selected high risk groups, indoor patients, and health workers. Because of the fear of contracting HIV through occupational exposure, 41.2% of students felt that girls may not choose a nursing career, while 10.7% were even thinking about leaving the profession. 58-72% were willing to nurse high risk patients, if provided adequate training and preventive measures in the health care settings. Nursing students need to be trained to provide humane, compassionate care to AIDS patients.