Central and peripheral serotonergic influences on viscerovisceral inhibitory reflex during duodenal distension in sheep

The effects of duodenal distension on forestomach and abomasal motility were investigated in conscious sheep chronically fitted with intraparietal electrodes, a duodenal cannula, and an intracerebroventricular cannula. Duodenal distensions with a balloon inflated with 40 ml (DD40) of water reduced the frequency of forestomach and abomasal contractions by 45 and 32%, respectively, while distension with 80 ml (DD80) induced a total inhibition. Methysergide, a mixed 5HT₁-5HT₂ antagonist administered intravenously (200 g/kg) or intracerebroventricularly (20 g/kg) suppressed the DD40-induced inhibition and reduced that induced by DD80. Sprioxatrine, a selective 5HT_1A antagonist, intravenously (100 g/kg) or intracerebroventricularly (10 g/kg), suppressed the DD40 and DD80-induced inhibition, which was also attenuated by the 5HT₂ antagonist ritanserin given intravenously (200 g/kg) or intracerebroventricularly (20 g/kg). Granisetron, a 5HT₃ antagonist, injected intravenously (150 g/kg), abolished the effects of DD40 and DD80 while it had no antagonistic action on DD40 and DD80 when given intracerebroventricularly (15 g/kg). It is concluded that in sheep, duodenal distension inhibits forestomach and abomasal motility through 5HT_1A and 5HT₂ receptors at the level of the central nervous system and 5HT₃ receptors located peripherally.This work was presented in part at the First United European Gastroenterology Week, September 25–30, 1992, Athens, Greece.     

Mupirocin resistance in nasal carriage of Staphylococcus aureus among healthcare workers of a tertiary care rural hospital

Introduction:

Mupirocin (pseudomonic acid A) is a topical antimicrobial agent with excellent antistaphylococcal and antistreptococcal activity. A nasal formulation is approved by the United States Food and Drug Administration for eradicating nasal carriage in adult patients as well as in health care personnel. Resistance to mupirocin has already been reported worldwide. The increasing prevalence of mupirocin resistance among Staphylococcus aureus and coagulase-negative Staphylococcus (CoNS) species could be an important threat to the future use of mupirocin against methicillin-resistant S. aureus (MRSA). Thus, this study was carried out to find the prevalence of mupirocin resistance in S. aureus and CoNS by disc diffusion and to determine the rates of high-level and low-level mupirocin resistance in S. aureus and CoNS by disc diffusion.

Materials and Methods:

A total of 140 healthcare workers (HCWs) (doctor, nursing staff, housekeeping staff) were randomly selected. S. aureus and CoNS isolates were tested for mupirocin resistance by the disk diffusion method using 5 μg and 200 μg mupirocin discs. MRSA isolates were tested for antibiotics by Kirby-Bauer disc-diffusion method as per Clinical and Laboratory Standards Institute guidelines.

Results:

Out of 140 nasal swabs collected from HCWs, S. aureus was isolated in 38 (27.14%), and CoNS was isolated in 73 (52.14%). MRSA was isolated in 20 (14.28%) and methicillin-resistant coagulase-negative Staphylococci (MRCoNS) in 34 (24.29%. Methicillin-sensitive S. aureus (MSSA) and MSCoNS isolates were 100% sensitive to mupirocin, but two isolates from MRSA (1.43%) and five from MRCoNS (3.57%) were mupirocin resistant.

Conclusion:

The presence of mupirocin resistance in MRSA and MRCoNS is a cause for concern. It could be limited by regular surveillance and effective infection control initiatives so to inform health care facilities to guide therapeutic and prophylactic use of mupirocin.     

Correlation of human S100A12 (EN-RAGE) and high-sensitivity C-reactive protein as gingival crevicular fluid and serum markers of inflammation in chronic periodontitis and type 2 diabetes

Objective

The aim of the present study was to evaluate the levels and correlation of human S100A12 and high-sensitivity C-reactive protein (hs-CRP) in gingival crevicular fluid (GCF) and serum in chronic periodontitis (CP) subjects with and without type 2 diabetes mellitus (DM).

Materials and methods

A total of 44 subjects were divided into three groups: group 1 had 10 periodontally healthy subjects, group 2 consisted of 17 CP subjects and group 3 had 17 type 2 DM subjects with CP. GCF and serum levels of human S100A12 and hs-CRP were quantified using enzyme-linked immunosorbent assay and immunoturbidimetric analysis, respectively. The clinical outcomes evaluated were gingival index, probing depth and clinical attachment level and the correlations of the two inflammatory mediators with clinical parameters were evaluated.

Results

Both human S100A12 and hs-CRP levels increased from group 1 to group 2 to group 3. The GCF and serum values of both these inflammatory mediators correlated positively with each other and with the periodontal parameters evaluated (p < 0.05).

Conclusion

Human S100A12 and hs-CRP can be considered as possible GCF and serum markers of inflammatory activity in CP and DM.     

Design and synthesis of 5‐(5‐nitrothiophen‐2‐yl)‐3‐phenyl‐4,5‐dihydro‐1H‐pyrazole derivatives with improved solubility and potential antituberculosis activity

We report the design‐synthesis of several nitrothiophene containing molecules as antituberculosis agents. The molecules were designed on the basis of previously reported nitrofuran molecules in our laboratory, and the α,β‐unsaturated linker was modified to cyclized linker in order to overcome the challenge of low solubility and possible toxicity. The stereo‐electronic properties such as HOMO, LUMO, and HOMO‐LUMO gap along with other properties such as aqueous solvation energies and QPLogS values were studied. The designed molecules were synthesized and tested for in vitro antituberculosis activity, and some molecules were found to be highly active comparable to standard drugs. Further, the aqueous solubility was determined using visual inspection method and the designed molecules were found to be more soluble than their chalcone counterparts. Cytotoxicity studies were performed and the molecules were found to be non‐cytotoxic. Electroanalytical studies proved nitro reduction as the mechanism of action for these molecules. Thus, this study provides potential nitrothiophene containing hits with improved solubility and reduced chances of toxicity.     

Neuronal calcium-binding proteins 1/2 localize to dorsal root ganglia and excitatory spinal neurons and are regulated by nerve injury

Neuronal calcium (Ca²⁺)-binding proteins 1 and 2 (NECAB1/2) are members of the phylogenetically conserved EF-hand Ca²⁺-binding protein superfamily. To date, NECABs have been explored only to a limited extent and, so far, not at all at the spinal level. Here, we describe the distribution, phenotype, and nerve injury-induced regulation of NECAB1/NECAB2 in mouse dorsal root ganglia (DRGs) and spinal cord. In DRGs, NECAB1/2 are expressed in around 70% of mainly small- and medium-sized neurons. Many colocalize with calcitonin gene-related peptide and isolectin B4, and thus represent nociceptors. NECAB1/2 neurons are much more abundant in DRGs than the Ca²⁺-binding proteins (parvalbumin, calbindin, calretinin, and secretagogin) studied to date. In the spinal cord, the NECAB1/2 distribution is mainly complementary. NECAB1 labels interneurons and a plexus of processes in superficial layers of the dorsal horn, commissural neurons in the intermediate area, and motor neurons in the ventral horn. Using CLARITY, a novel, bilaterally connected neuronal system with dendrites that embrace the dorsal columns like palisades is observed. NECAB2 is present in cell bodies and presynaptic boutons across the spinal cord. In the dorsal horn, most NECAB1/2 neurons are glutamatergic. Both NECAB1/2 are transported into dorsal roots and peripheral nerves. Peripheral nerve injury reduces NECAB2, but not NECAB1, expression in DRG neurons. Our study identifies NECAB1/2 as abundant Ca²⁺-binding proteins in pain-related DRG neurons and a variety of spinal systems, providing molecular markers for known and unknown neuron populations of mechanosensory and pain circuits in the spinal cord.Calcium (Ca²⁺) plays a crucial role in many and diverse cellular processes, including neurotransmission (1). Glutamate and neuropeptides are neurotransmitters released from the central terminals of dorsal root ganglion (DRG) neurons in the spinal dorsal horn, where signals for different sensory modalities, including pain, are conveyed to higher centers (2–12). Neurotransmitter release is tightly regulated by Ca²⁺-dependent SNARE proteins whose activity is regulated by Ca²⁺-binding proteins (CaBPs) (1, 7, 13).Parvalbumin (PV), calbindin D-28K (CB), calretinin (CR), and secretagogin (Scgn) are extensively studied EF-hand CaBPs, and they have also emerged as valuable anatomical markers for morphologically and functionally distinct neuronal subpopulations (14–17). The expression of CaBPs in DRG neurons has been thoroughly studied (18). Moreover, neuronal Ca²⁺ sensor 1 and downstream regulatory element-antagonist modulator (DREAM) are also EF-hand Ca²⁺-binding proteins in DRGs and the spinal cord (19, 20). Despite these advances, a CaBP has so far not been characterized in the majority of small- and medium-sized DRG neurons, many of which represent nociceptors.The subfamily of neuronal Ca²⁺-binding proteins (NECABs) consists of three members (NECAB1–NECAB3), probably as a result of gene duplication (21). NECABs are also EF-hand proteins, with one pair of EF-hand motifs in the N terminus and a putative antibiotic biosynthesis monooxygenase domain in the C terminus, which are linked by a NECAB homogeneous region (22). NECAB1/2 are restricted to the nervous system, whereas NECAB3 is also expressed in the heart and skeletal muscle (21).NECAB1 was first identified as the target protein of synaptotagmin I C2A-domain by affinity chromatography, with its expression restricted to layer 4 cortical pyramidal neurons, inhibitory interneurons, and hippocampal CA2 pyramidal cells in mouse brain (21, 23). The gene of the second member was cloned from mouse and initially named Necab. It encodes a 389-aa (NECAB2) (24). NECAB2 was identified as a downstream target of Pax6 in mouse retina, which is involved in retinal development (24, 25), as well as being a binding partner for the adenosine A_2A receptor (22). Furthermore, an interaction between NECAB2 and metabotropic glutamate receptor 5 (mGluR5) was demonstrated in rat hippocampal pyramidal cells, possibly regulating mGluR5’s coupling to its signaling machinery (26). Finally, NECAB3, also known as XB51, was isolated as an interacting target for the neuron-specific X11-like protein and is possibly involved in the pathogenesis of Alzheimer’s disease (27, 28).Very recently, NECAB1/2 were shown to have complementary expression patterns in mouse hippocampus at the mRNA and protein levels, whereas NECAB3 is broadly distributed in the hippocampus (29). NECAB1-expressing cells were seen throughout the cell-sparse layers of Ammon’s horn and the hilus of the dentate gyrus. In contrast, NECAB2 is enriched in pyramidal cells of the CA2 region. A minority of NECAB1⁺ neurons were GABAergic yet did not coexpress PV, CB, or CR (29).Here, we investigated the expression of NECAB1/2 in mouse DRGs and spinal cord using quantitative PCR (qPCR), immunohistochemistry (also combined with CLARITY) (30), and Western blotting. We compared the distribution of NECABs with that of the four CaBPs restricted to neurons, PV, CB, CR, or Scgn. NECAB⁺ neurons in the spinal dorsal horn were phenotyped using transgenic mice harboring genetic markers for excitatory [vesicular glutamate transporter 2 (VGLUT2)] (31) or inhibitory [glutamate decarboxylase 67 (GAD67)] (32) cell identities. Finally, the effect of peripheral nerve injury was analyzed.