Reducing mortality in mucormycosis of the head and neck in diabetic patients: A CARE case series.

INTRODUCTION: Rhinocerebral mucormycosis is extremely fatal, with mortality rates ranging from 85-93% despite the best treatment in immunocompromised patients. We emphasize the importance of early diagnosis, repeated debridement, and aggressive antifungal treatment to reduce mortality. CASE SUMMARY: We report six cases (five male and one female), with a mean age of 51 years who were diagnosed to have mucormycosis from 2017 to 2019. All patients were diabetic. Intracranial involvement and orbital involvement were found in four cases. Facial nerve palsy was seen in two cases, one without any apparent otological involvement. Aggressive serial debridement and amphotericin B was started. Posaconazole was added subsequently to the treatment in two cases. One patient succumbed to the disease five months after discharge. The other five patients are on regular follow-up for a mean duration of 14 months at the end of which two had residual disease which was under control. DISCUSSION: Repeated surgical debridement with an early aggressive and combination antifungal therapy can result in good outcomes even in advanced mucormycosis. Concurrent management of the underlying pathology, monitoring of liver and kidney functions, and therapeutic drug monitoring are useful to ensure smooth and effective treatment.

Correlation of cochlear nerve cross-sectional area and auditory performance after cochlear implantation in prelingual children with bilateral profound hearing loss.

OBJECTIVE: To assess whether cochlear nerve (CN) cross-sectional area as measured with parasagittal magnetic resonance imaging (MRI) in prelingual pediatric deaf patients correlates with auditory performance after cochlear implantation. STUDY DESIGN: Prospective Cohort study. METHODS: Thirty-two prelingual children with bilateral profound sensorineural hearing loss (SNHL) who received unilateral cochlear implant were included in this study. Diameters of CN at Internal auditory canal (IAC) fundus and mid-point of IAC were retrospectively measured on parasagittal images of FIESTA (Fast Imaging Employing Steady-state Acquisition) sequence MRI by two independent observers. Cross-sectional areas [π (Height/2) (Width/2)] were then correlated with post-operative CAPS (Categories of Auditory Performance) and IT-MAIS (Infant-Toddler Meaningful Auditory Integration Scale) scores regularly assessed at 3 monthly intervals post device activation. RESULTS: The cochlear nerve was identified in all the 32 patients. Mean cross-sectional areas (CSA) of cochlear nerve were 0.71 ± 0.16 mm2 at IAC fundus and 0.73 ± 0.18 mm2 at mid-point of IAC. The correlation value between CSA at mid-point of IAC and CAPS score at 6 months was 0.271 (p-value- 0.140) and correlation value between CSA at mid-point of IAC and IT-MAIS score at 6 months was 0.282 (p-value- 0.124) which were statistically not significant. CONCLUSION: There was no significant correlation between the cross-sectional areas of the cochlear nerve on MRI and postoperative auditory scores as measured by CAPS and IT-MAIS scores at six months from the device activation. Hence, we conclude that above an adequate diameter, which can affect the minimum required neurons, the changes in the diameter do not have significant bearing on auditory outcomes after cochlear implantation.

Morphometric evaluation of Anterior Cerebral Artery (on Digital Subtraction Angiography)-Potential implications.

PURPOSE: The aim of the present study was to perform a morphometric analysis of ACA and to establish significant differences, if any, with sex and age via Digital Subtraction Angiography (DSA). METHODS: This cross-sectional study was conducted on 70 patients (>20 years) for the evaluation of ACA by Digital Subtraction Angiography done on a Philips biplane system clarity (Allura FD20/20). Length and diameter of ACA were taken manually on the DSA console using auto-calibration. Statistical analysis was done. RESULT: Mean diameter and length of ACA was found to be greater in female. The f-ratio value for diameter and length of the same was 1.43 and 0.92 respectively. The length of ACA was found to be statistically significant for different age groups. The mean length of ACA followed a decreasing trend with age, whereas mean diameter of ACA was nearly the same in all the age groups. CONCLUSION: The results of our study show that the length of ACA was found to be statistically significant for different age groups.

Short-term (48 hours) versus long-term (7 days) antibiotic prophylaxis for permanent pacemaker implantation.

BACKGROUND: Infection following permanent pacemaker implantation is a dreaded complication. Antibiotic prophylaxis for 1-10 days at the time of implant has been used in the past but there is no consensus regarding its duration. We carried out a prospective, randomized study of two durations of antibiotic prophylaxis to determine which one was more effective. METHODS AND RESULTS: One hundred and seventy-eight patients undergoing permanent pacemaker implantation for the first time were randomized to receive short duration (group A, n = 8 8) or longer duration (group B, n = 90) antibiotic prophylaxis for 2 days and 7 days, respectively. Patients in both groups received cloxacillin 2 g 2 hours prior to the procedure followed by ampicillin and cloxacillin (50 mg/kg/day in 4 divided doses) and gentamicin (3 mg/kg/day in 2 divided doses) for the respective duration. Patients were followed up for 1-17.3 months (9.3 +/- 1.8 months) in group A and 1-16.5 months (8.9 +/- 2 months) in group B. One patient in group B had an infection at the pacemaker site and two patients in each group had to undergo reimplantation due to pus in the pocket. There was no significant difference in the primary end-point in both groups. CONCLUSIONS: A short course (48 hours) of antibiotic prophylaxis following permanent pacemaker implantation is as effective as a longer course (7 days).

Parathyroid hormone-related protein induces G1 phase growth arrest of vascular smooth muscle cells.

In this study, we investigated the mechanisms responsible for the growth-inhibitory action of parathyroid hormone-related protein (PTHRP) in A10 vascular smooth muscle cells (VSMC). Fluorescence-activated cell sorting analysis of serum-stimulated VSMC treated with PTHRP or dibutyryl-cAMP (DBcAMP) demonstrated an enrichment of cells in G1 and a reduction in the S phase. Measurement of DNA synthesis in platelet-derived growth factor-stimulated VSMC treated with DBcAMP revealed that cells became refractory to growth inhibition by 12-16 h, consistent with blockade in mid-G1. cAMP treatment blunted the serum-induced rise in cyclin D1 during cell cycle progression without altering levels of the cyclin-dependent kinase cdk4 or cyclin E and its associated kinase, cdk2. Exposure of cells to PTHRP or cAMP resulted in a reduction in retinoblastoma gene product (Rb) phosphorylation. Immunoblotting of extracts from cAMP-treated cells with antibodies to cdk inhibitors revealed a striking increase in p27(kip1) abundance coincident with the G1 block. Immunoprecipitation with an anti-cyclin D1 antibody of cell lysates prepared from cAMP-treated cells followed by immunoblotting with antisera to p27(kip1) disclosed a threefold increase in p27(kip1) associated with cyclin D1 compared with lysates treated with serum alone. We conclude that PTHRP, by increasing intracellular cAMP, induces VSMC cycle arrest in mid-G1. This occurs secondary to a suppression in cyclin D1 and induction of p27(kip1) expression, which in turn inhibits Rb phosphorylation.

Importance of highly conserved anionic residues and electrostatic interactions in the activity and structure of the cardiotonic polypeptide anthopleurin B.

Several polypeptide toxins from sea anemones caused delayed inactivation of mammalian voltage-dependent sodium channels, resulting in a positive inotropic effect on the heart. Anthopleurin B (ApB), a toxin produced by the sea anemone Anthopleura xanthogrammica, is the most potent of all known anemone toxins. Previous studies in this laboratory have both defined and revealed an important role for the cationic cluster of Arg-12, Arg-14, and Lys-49 in the expression of ApB's biological activity. In the present investigation, we explore the role of all remaining charged residues by producing and characterizing mutants of ApB at Asp-7, Asp-9, Lys-37, His-39, and His-34. Recombinant toxins have been purified to homogeneity and their abilities to enhance veratridine-dependent sodium uptake in cell lines expressing either the neuronal or cardiac isoform of the sodium channel evaluated. Replacement of Asp-7 results in a product that fails to fold, while muteins H39A and H34A have activities very similar or identical to wild-type ApB. In contrast, the D9N and K37A muteins are 7-12-fold less active that wild-type ApB, and truncation of the side chain in D9A results in a further decrease in activity, especially in the cardiac model. We conclude that although a negative charge per se is not essential at position 9, the presence of a hydrogen-bond forming side chain is critical both for appropriate folding and for interaction with the sodium channel. Because the K37A and H39A mutant toxins can fold normally, neither Lys-37 nor His-39 seem to participate in an intramolecular salt bridge, in contrast to suggestions arising from NMR studies of ApA and ApB. However, Lys-37 may play a role in channel interaction.

Multiple cationic residues of anthopleurin B that determine high affinity and channel isoform discrimination.

Site 3 sea anemone toxins modify inactivation of mammalian voltage-gated Na channels. One variant, anthopleurin A (ApA), effectively selects for cardiac over neuronal mammalian isoforms while another, anthopleurin B (ApB), which differs in 7 of 49 amino acids, modifies both cardiac and neuronal channels with high and approximately equal affinity. Previous investigations have suggested an important role for cationic residues in determination of toxin activity, and our single-site mutagenesis studies have indicated that isoform discrimination can be partially explained by the unique cationic residues Arg-12 and Lys-49 of anthopleurin B (ApB). Here, we have further investigated the role of cationic residues by characterizing toxin mutants in which two such residues are replaced simultaneously. The ApB double mutants R14Q-K48A (cationic residues identical in both ApA and ApB), R12S-K49Q (cationic residues unique to ApB), and R12S-R14Q (cationic residues located in the unstructured loop shared among anemone toxins) were constructed by site-directed mutagenesis and their biological activities characterized by sodium uptake assays in cell lines expressing the neuronal (N1E-115) or cardiac (RT4-B) isoform of the Na channel. Each double mutant displayed reduced activity compared with wild type, but none were completely inactive. Neutralization of the proximal cationic residues (R12 and R14) was the most effective, reducing affinity 72-fold (neuronal) and 56-fold (cardiac). Substitution of cationic residues that differed between ApB and ApA (R12S-K49Q) reduced affinity of the toxin for neuronal channels to a much greater extent than for cardiac channels, producing affinities only slightly lower than for ApA in each case.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of the cationic residues arginine 14 and lysine 48 in the function of the cardiotonic polypeptide anthopleurin B.

Polypeptide neurotoxins from sea anemones have been useful biological probes for sodium channel function. Cationic residues, specifically Arg-14, which is conserved in essentially all known sea anemone toxins, have been generally thought to be important determinants of their binding affinity and/or efficacy. In the present study, we have constructed site-directed mutants of the Anthopleura xanthogrammica toxin anthopleurin B (ApB) at Arg-14 and Lys-48 to characterize the roles played by these cationic residues in the biological activity of the toxin. Using a bacterial expression system developed in this laboratory, we have produced recombinant proteins having three substitutions at each of these positions. The proteins produced have been purified to homogeneity and have structures and conformational stabilities identical to wild-type ApB. We have assayed the mutants by determining their ability to enhance the veratridine-dependent uptake of sodium by both N1E-115 neuroblastoma cells and RT4-B cells, which express the cardiac/denervated skeletal muscle sodium channel. All mutants showed activities only slightly reduced from that of wild-type ApB, with the greatest reductions (4- and 6-fold) being observed for the mutants R14A and K48A, respectively. We conclude that contrary to results from chemical modification studies, Arg-14 is not essential for the biological activity of the toxin. Our data also indicate that Lys-48 plays a small but discernible role in the toxin-receptor interaction.

The origin of vacuoles in young embryos of Pelargonium x Hortorum Bailey.

The different mechanisms of vacuole formation in embryonic tissues of Pelargonium are described. Some vacuoles are formed by mechanisms widely reported in a variety of plant species and plant tissues, but other vacuoles are initiated as differentiated zones of the cytoplasm around which the tonoplast is gradually built up form vesicles and small cisternae.