Identification of microbial agents in culture-negative brain abscess samples by 16S/18S rRNA gene PCR and sequencing

@#Despite clinical suspicion of an infection, brain abscess samples are often culture-negative in routine microbiological testing. Direct PCR of such samples enables the identification of microbes that may be fastidious, non-viable, or unculturable. Brain abscess samples (n = 217) from neurosurgical patients were subjected to broad range 16S rRNA gene PCR and sequencing for bacteria. All these samples and seven formalin-fixed paraffin-embedded tissue (FFPE) samples were subjected to species-specific 18S rRNA PCR for neurotropic free-living amoeba that harbour pathogenic bacteria. The concordance between smear and/or culture and PCR was 69%. One-third of the samples were smear- and culture-negative for bacterial agents. However, 88% of these culture-negative samples showed the presence of bacterial 16S rRNA by PCR. Sanger sequencing of 27 selected samples showed anaerobic/fastidious gram negative bacteria (GNB, 38%), facultative Streptococci (35%), and aerobic GNB (27%). Targeted metagenomics sequencing of three samples showed multiple bacterial species, including anaerobic and non-culturable bacteria. One FFPE tissue revealed the presence of Acanthamoeba 18S rRNA. None of the frozen brain abscess samples tested was positive for 18S rRNA of Acanthamoeba or Balamuthia mandrillaris. The microbial 16/18S rRNA PCR and sequencing outperformed culture in detecting anaerobes, facultative Streptococci and FLA in brain abscess samples. Genetic analyses of 16S/18S sequences, either through Sanger or metagenomic sequencing, will be an essential diagnostic technology to be included for diagnosing culture-negative brain abscess samples. Characterizing the microbiome of culture-negative brain abscess samples by molecular methods could enable detection and/or treatment of the source of infection.

Central nervous system infections caused by pathogenic free-living amoebae: An Indian perspective

@#Pathogenic free-living amoebae (FLA), namely Acanthamoeba sp., Naegleria fowleri and Balamuthia mandrillaris are distributed worldwide. These neurotropic amoebae can cause fatal central nervous system (CNS) infections in humans. This review deals with the demographic characteristics, symptoms, diagnosis, and treatment outcomes of patients with CNS infections caused by FLA documented in India. There have been 42, 25, and 4 case reports of Acanthamoeba granulomatous amoebic encephalitis (GAE), N. fowleri primary amoebic meningoencephalitis (PAM), and B. mandrillaris meningoencephalitis (BAE), respectively. Overall, 17% of Acanthamoeba GAE patients and one of the four BAE patients had some form of immunosuppression, and more than half of the N. fowleri PAM cases had history of exposure to freshwater. Acanthamoeba GAE, PAM, and BAE were most commonly seen in males. Fever, headache, vomiting, seizures, and altered sensorium appear to be common symptoms in these patients. Some patients showed multiple lesions with edema, exudates or hydrocephalus in their brain CT/MRI. The cerebrospinal fluid (CSF) of these patients showed elevated protein and WBC levels. Direct microscopy of CSF was positive for amoebic trophozoites in 69% of Acanthamoeba GAE and 96% of PAM patients. One-fourth of the Acanthamoeba GAE and all the BAE patients were diagnosed only by histopathology following autopsy/biopsy samples. Twenty-one Acanthamoeba GAE survivors were treated with cotrimoxazole, rifampicin, and ketoconazole/amphotericin B, and all eleven PAM survivors were treated with amphotericin B alongside other drugs. A thorough search for these organisms in CNS samples is necessary to develop optimum treatment strategies.

Craniospinal irradiation for respiratory failure secondary to central nervous system Erdheim-Chester disease

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis typically featuring lower extremity osteosclerosis (96%) from Langerin-negative histiocytes with fibrosis. Central nervous system (CNS)-only disease is extremely rare, and particularly difficult to diagnose and manage. Neurologic complaints may be refractory to systemic therapy (ST), and the role of radiation therapy (RT) is undefined. We present a patient with ECD of the medulla complicated by respiratory failure and strength deficits with disseminated leptomeningeal disease (LMD) but not systemic disease, representing the first report of CNS-limited ECD with LMD. He received upfront craniospinal irradiation (CSI), representing a rare account of CSI for ESD, with marked clinical improvement resulting in extubation and improved strength. CSI facilitated excellent preservation of quality of life, and no treatment-related toxicity was observed prior to eventual, unrelated cardiopulmonary arrest. Thus, palliative CSI may augment ST by safely offering improved local control and symptomatic relief for CNS ECD.

Radioprotective natural products as alternative complements in oncological radiotherapy / Productos naturales radioprotectores como complementos alternativos en la radioterapia oncológica

Humans when exposed to harmful ionising radiations suffer from various pathophysiological disorders including cancer. Radiotherapy is a treatment where these cancerous cells within a tumor aretargeted and killed by means of high energy waves. This therapy is very expensive and involves highly sophisticated instruments. In addition to this, most synthetic radioprotectors including Amifostine have been found to possess toxicity. This led researchers to develop a novel, economically viable, and efficient therapeutic alternative to radiation therapy. The last two decades have observed a major shift towards investigating natural products as radioprotectors, as these are immensely effective in terms of their potential bioequivalence relative to many of the established synthetic compounds available. Taking into account the limitations of radiation therapy, an approach 'Integrative Oncology' that involves a combination of both traditional and conventional medical treatment are used nowadays to treat patients suffering from cancer and associated mental and psychological disorders.

Los seres humanos, cuando se exponen a radiaciones ionizantes nocivas, sufren diversos trastornos fisiopatológicos, incluido el cáncer. La radioterapia es un tratamiento en el que estas células cancerosas dentro de un tumor son atacadas y destruidas por medio de ondas de alta energía. Esta terapia es muy cara e implica instrumentos muy sofisticados. Además de esto, se ha descubierto que la mayoría de los radioprotectores sintéticos, incluida la amifostina, poseen toxicidad. Esto llevó a los investigadores a desarrollar una novedosa, económicamente viable y eficiente alternativa terapéutica a la radioterapia. En las dos últimas décadas se ha observado un cambio importante hacia la investigación de productos naturales como radioprotectores, ya que son inmensamente eficaces en términos de su potencial bioequivalencia en relación con muchos de los compuestos sintéticos establecidos disponibles. Teniendo en cuenta las limitaciones de la radioterapia, hoy en día se utiliza un enfoque de "Oncología Integrativa" que implica una combinación de tratamiento médico tradicional y convencional para tratar a pacientes que padecen cáncer y trastornos mentales y psicológicos asociados.

Perceptions of Medical students on “Timing of theory classes”

Background and Objectives: Most research has found that‘timing of classes’ play a significant part in studentachievement. When students were taught at times matchingtheir preferences, scores were significantly higher onachievement tests. If time is viewed as a resource and can beinfluenced to support high quality instruction, preferred time-ofday is much more likely to result in improved learning.Currently, medical schools are not set up to match everystudent’s perception on ‘timing of the class’. Therefore, there isa need for research on ‘timing of the theory class’ for medicalstudents.Materials and Methods: A cross sectional observational studywas conducted and perceptions of students belonging toMBBS stream from first semester to seventh semester wereconsidered for our study. Structured questionnaire was used inthe format of five-point Likert scale for every statementregarding the timing of theory classes, dissection hours, postlunch theory classes, interactive sessions, audio-visual aidsand experience of teaching faculty. Results were analyzed withthe help of MS office Excel and SPSS software version 20. Wehave compared the perceptions of medical students on fivepoint Likert scale on each question and the statisticalsignificance was calculated by Chi Square test.Results: Our study included a total of 505 medical studentsacross the semesters in MBBS stream. 33.1% of the studentsagreed to come for the theory class at 8° clock, across allsemesters and 34.1% of first semester students agreed tocome for 8° clock theory class when compared to 43% in 3rdSemester, 23.7% in 5th semester and 30.2% in 7th semesterstudents. In our study 50.8% of students from first semesterdisagreed to schedule ‘dissection classes’, of anatomy in thefirst hours of the day and 42.8% of students perceived thatattention span was good in the morning class. 34.1% of thefirst semester students perceived that ‘the quality of theteacher’ makes the class more interesting irrespective of timeof the day.Conclusion: Medical students perceive differently on ‘thetiming of theory classes’ across the semesters. Our studyprovides insights into student’s perceptions regarding lack ofattention during classes; which may be useful in identifyingtheir expectations and to plan theory classes in the curriculum.

Evaluation of anti-allergic and anti-anaphylactic activity of ethanolic extract of Zizyphus jujuba fruits in rodents

The present study reports the anti-allergic activity of ethanolic extract of Zizyphus jujuba Mill., Rhamnaceae, and its possible mode of action. The effect of extract of Z. jujuba at different doses (250, 500 and 1000 mg/kg, orally) was simulated on studied animal models of asthma and allergy: a) milk induced eosinophilia and leukocytosis; b) compound 48/80 induced mast cell degranulation; and, c) active and passive cutaneous anaphylaxis. In addition, extract of Z. jujuba's effect on sensitized guinea pig ileum (ex vivo) and tracheal chain preparations (in vitro) were investigated.Treatment with extract of Z. jujuba at all doses significantly: prevented the milk-induced eosinophilia and compound 48/80 induced degranulation of mesenteric mast cells; decreased passive cutaneous and active anaphylactic reactions. In addition, extract of Z. jujuba inhibited acetylcholine as well as histamine induced tracheal chain contraction, and also antigen induced contraction of sensitized guinea pig ileum (Shultz-Dale inhibition test). Furthermore, it exhibited also free radicals scavenging activity (in vitro). The observed anti-allergic and anti-anaphylactic activity of extract of Z. jujuba may be largely through the stabilization of mast cells by the membrane presence of phytoconstituents (steroidal saponins and flavonoids).

Chitosan/guargum-g-acrylamide semi IPN microspheres for controlled release studies of 5-Fluorouracil.

Chitosan and guargum-gt-acrylamide (CH-GG-g-AAm) semi interpenetrating microspheres (semi IPNMs) were prepared by water-in-oil (w/o) emulsion cross linking method using glutaraldehyde as a crosslinker. 5-fluorouracil (5-FU) is an anticancer drug was successfully loaded in these semi IPNMs. X-ray diffraction (XRD) and differential scanning calorimetric (DSC) examined the crystalline nature of drug after encapsulation into semi IPNMs. Scanning electron microscopy (SEM) shows the formation of semi IPNMs is spherical with size around 200 􀀀m. The encapsulation efficiency of 5-FU was achieved 58%. In-vitro release studies were performed basic (pH 7.4) buffer medium. The release patterns depend on graft polymer composition, effect of cross linker and drug content in the polymer matrices. In vitro release studies indicated the release of 5- FU more than 12 hours.

Magnesium perchlorate [Mg (ClO4)2] catalyst one-pot synthesis of 3,4-DI hydropyrimidin-2(1H)-ones: an improved procedure for biginelli condensation.

3, 4-Dihydropyrimidinones were synthesized very efficiently in excellent yields, while using the magnesium perchlorate as catalyst. This protocol can be applicable to a wide range of aldehydes, ethylacetoacetate and urea. The reaction conditions were very mild and the isolation of products also very easy.

Incidence of complications following 5-fluorouracil with trabeculectomies.

To investigate the incidence of complications reportedly caused by the use of 5-fluorouracil (5-FU) in glaucoma filtering surgery, we performed trabeculectomy with 5-FU on 57 eyes of 56 patients with advanced glaucoma. The mean preoperative intraocular pressure was 34.8 mm Hg. The most frequent complication encountered was superficial punctate keratopathy (26%), followed by shallowing of the anterior chamber (12%), choroidal detachment (9%), and flap retraction (7%). We, however, did not encounter any cases of confluent corneal epithelial defect, subepithelial scarring, or striate melanokeratosis which are usually described with the use of 5-FU. With a mean follow-up of 7.1 months, an intraocular pressure less than 16 mm Hg without hypotensive therapy were achieved in 73.7% of cases, and less than 21 mm Hg without hypotensive therapy in 86%. Considering the low incidence of complications and the high success rate, we recommend the use of 5-FU in routine glaucoma filtering surgery.

Releasable suture technique for trabeculectomy.

We studied the effect of the releasable suture technique on immediate postoperative intraocular pressure (IOP). Nine eyes of nine patients with glaucoma had trabeculectomy with a releasable suture. In the six eyes that did not receive antimitotics, the suture was released by the fifth postoperative day; in the others suture release was delayed up to the fourteenth day. Of the nine patients, one had an acceptable postoperative IOP and did not need suture release; in another the suture broke and could not be released. In the remaining seven patients, the difference between the pre-release and post-release IOP was statistically significant (p < 0.001). The complications of this technique include failed suture release, subconjunctival hematoma and a distinctive "windshield wiper" keratopathy.

Anterior capsular support for posterior chamber intraocular lenses following vitreous loss in endocapsular surgery.

We used anterior capsular support for posterior chamber intraocular lenses (PC IOLs) in fourteen eyes with large posterior capsular ruptures. An endocapsular technique preserved the anterior capsule and facilitated implantation. With a median follow up of 8.5 months, all patients had a visual acuity of 6/9 or better. One lens was lost in the vitreous and one patient had a clinically significant cystoid macular edema. In the event of a posterior capsular rupture we suggest this technique as an alternative to anterior chamber or scleral-fixated lenses.

Islet cell antigens and autoantigen(s): Monoclonal antibodies and further characterization.

A novel series of murine monoclonal antibodies to islet cells (I-45, I-51, I-52 and I-39) have been generated using human insulinoma homogenate as the immunogen in order to characterize pathogenetically relevant islet cell autoantigen(s). Differentiation antigens recognized by these islet cell monoclonal antibodies displayed varied cytological distribution (pan-islet or peripheral mantle only). Monoclonal antibody I-45 reacted with all endocrine subsets of the pancreatic islet, similar to the reactivity of islet cell autoantibody positive sera from type I diabetes subjects. Preexposure to pH2 abolished the immunoreactivity of the autoantigen; I-45 antigen was also sensitive to low pH. Preexposure to 100° C for 1 h did not significantly alter the immunoreactivity of islet antigens recognized by ICAb positive patient sera and monoclonal antibody 1-39, thus demonstrating the extraordinary heat stability of the corresponding epitopes; those recognized by I-45 were less heat stable. Islet cells were found to share I-45 differentiation antigen(s)/epitope(s) with other neuroendocrine cells, viz. amerior pituitary, adrenal medulla and gut endocrine cells.

Morphometric analysis of coronary lesions in patients with unstable angina--an arteriographic study.

In 100 patients with unstable angina and 50 patients with stable angina qualitative morphology of coronary artery lesions were compared by angiography. The mean age of the patients was 51 years. In the unstable angina group, 50 patients had rest angina, 32 had crescendo angina and 18 had denovo angina; 31 patients had single vessel disease, 33 had two vessel disease, 34 had triple vessel disease and 2 had left main disease. 'Angina-producing' artery could be identified in 90 out of 100 patients. Ten totally occluded vessels were excluded from analysis. Lesions causing diameter stenosis of greater than 50% could be categorised to one of the following groups: a) Concentric stenosis (18 vessels), b) Type I eccentric lesion (asymmetric narrowing with smooth borders and broad neck--20 vessels), c) Type II eccentric lesion (asymmetric narrowing with narrow neck and overhanging irregular edges--47 vessels), and d) Multiple irregularities (15 vessels). Lesions in 9 vessels showed an associated thrombus. It appears that Type II eccentric lesions are frequent in patients with unstable angina; they probably represent ruptured atherosclerotic plaque or partially occlusive thrombi or both.