A randomized phase 2 study on demeclocycline in patients with mild-to-moderate COVID-19.

Tetracyclines exhibit anti-viral, anti-inflammatory, and immunomodulatory activities via various mechanisms. The present study investigated the efficacy and safety of demeclocycline in patients hospitalized with mild-to-moderate COVID-19 via an open-label, multicenter, parallel-group, randomized controlled phase 2 trial. Primary and secondary outcomes included changes from baseline (day 1, before the study treatment) in lymphocytes, cytokines, and SARS-CoV-2 RNA on day 8. Seven, seven, and six patients in the control, demeclocycline 150 mg daily, and demeclocycline 300 mg daily groups, respectively, were included in the modified intention-to-treat population that was followed until day 29. A significant change of 191.3/µL in the number of CD4+ T cells from day 1 to day 8 was observed in the demeclocycline 150 mg group (95% CI 5.1/µL-377.6/µL) (p = 0.023), whereas that in the control group was 47.8/µL (95% CI - 151.2/µL to 246.8/µL), which was not significant (p = 0.271). The change rates of CD4+ T cells negatively correlated with those of IL-6 in the demeclocycline-treated groups (R = - 0.807, p = 0.009). All treatment-emergent adverse events were of mild-to-moderate severity. The present results indicate that the treatment of mild-to-moderate COVID-19 patients with demeclocycline elicits immune responses conducive to recovery from COVID-19 with good tolerability.Trial registration: This study was registered with the Japan Registry of Clinical Trials (Trial registration number: jRCTs051200049; Date of the first registration: 26/08/2020).

Development and Reversal of Discolouration in Roots Filled with Ledermix or Doxymix Pastes Stored in the Dark for Three Months then Daylight for Twenty Four Months.

OBJECTIVE: To explore the long-term effects on discolouration by demeclocycline HCl (Ledermix, LED) or doxycycline hyclate (Doxymix, DOX) pastes placed in extracted human teeth over a 27-month period under different storage conditions. METHODS: The canals in 38 teeth were prepared carefully, to minimize exposure to contamination from irrigants, then either LED (Lederle Pharmaceuticals, Germany) or DOX (Ozdent, Australia) were placed. Samples were stored in the dark for 3 months followed by daylight for 24 months. The storage conditions varied as follows: Group 1: Open access, dry storage (OD); Group 2: Closed access, dry storage (CD); Group 3: Open access, wet storage (OW); Group 4: Closed access, wet storage (n=4 for each material). Additional teeth were used as controls: Polyethylene glycol only in a closed canal; and saline only irrigation with LED paste in a closed canal. Standardised digital photographs were taken over 27 months and evaluated for changes in luminosity. RESULTS: Darkening of tooth structure occurred in all LED groups and in the two DOX groups that were stored wet, during exposure to light, with a faster rate with LED. The most rapid staining occurred with LED in moist conditions with an open access cavity. The least staining occurred with DOX in samples stored dry. With prolonged exposure to light, a reversal in staining occurred with DOX at 3 months and LED at 9 months. CONCLUSION: Staining of tooth structure is influenced by the choice of medicament, and by exposure to moisture and air. Light has a bimodal effect, first driving staining, but later reversing it. This can be explained by different wavelengths of light causing photodegradation and photo-oxidation of tetracyclines and their complexes with tooth mineral.

Neuroprotective Effects of a Novel Demeclocycline Derivative Lacking Antibiotic Activity: From a Hit to a Promising Lead Compound.

The antibiotic tetracycline demeclocycline (DMC) was recently reported to rescue α-synuclein (α-Syn) fibril-induced pathology. However, the antimicrobial activity of DMC precludes its potential use in long-term neuroprotective treatments. Here, we synthesized a doubly reduced DMC (DDMC) derivative with residual antibiotic activity and improved neuroprotective effects. The molecule was obtained by removal the dimethylamino substituent at position 4 and the reduction of the hydroxyl group at position 12a on ring A of DMC. The modifications strongly diminished its antibiotic activity against Gram-positive and Gram-negative bacteria. Moreover, this compound preserved the low toxicity of DMC in dopaminergic cell lines while improving its ability to interfere with α-Syn amyloid-like aggregation, showing the highest effectiveness of all tetracyclines tested. Likewise, DDMC demonstrated the ability to reduce seeding induced by the exogenous addition of α-Syn preformed fibrils (α-SynPFF) in biophysical assays and in a SH-SY5Y-α-Syn-tRFP cell model. In addition, DDMC rendered α-SynPFF less inflammogenic. Our results suggest that DDMC may be a promising drug candidate for hit-to-lead development and preclinical studies in Parkinson's disease and other synucleinopathies.

Electrooxidation of tetracycline antibiotic demeclocycline at unmodified boron-doped diamond electrode and its enhancement determination in surfactant-containing media.

In this paper, for the first time, the study of voltammetric determination of tetracycline antibiotic demeclocycline was conducted. The oxidation of compound was investigated using a commercially available boron-doped diamond electrode pretreated electrochemically (anodic and subsequent cathodic). Addition of anionic surfactant, sodium dodecylsulfate (SDS) and cationic surfactant, cetyltrimethylammonium bromide (CTAB) to the demeclocycline-containing electrolyte solution at pH 2.0 and 9.0, respectively, was found to improve the sensitivity of the stripping voltammetric measurements. Employing square-wave stripping mode (after 30 s accumulation at open-circuit condition) in Britton-Robinson buffer, the limits of detection were found to be 1.17 µg mL-1 (2.3 × 10-6 M) for 4 × 10-4 SDS-containing buffer solution at pH 2, and 0.24 µg mL-1 (4.8 × 10-7 M) for 1 × 10-4 CTAB-containing buffer solution at pH 9.0. The feasibility of the developed approach for the quantification of demeclocycline was tested in urine samples.

Demeclocycline Reduces the Growth of Human Brain Tumor-Initiating Cells: Direct Activity and Through Monocytes.

Myeloid cells that infiltrate into brain tumors are deactivated or exploited by the tumor cells. We previously demonstrated that compromised microglia, monocytes, and macrophages in malignant gliomas could be reactivated by amphotericin-B to contain the growth of brain tumorinitiating cells (BTICs). We identified meclocycline as another activator of microglia, so we sought to test whether its better-tolerated derivative, demeclocycline, also stimulates monocytes to restrict BTIC growth. Monocytes were selected for study as they would be exposed to demeclocycline in the circulation prior to entry into brain tumors to become macrophages. We found that demeclocycline increased the activity of monocytes in culture, as determined by tumor necrosis factor-α production and chemotactic capacity. The conditioned medium of demeclocycline-stimulated monocytes attenuated the growth of BTICs generated from human glioblastoma resections, as evaluated using neurosphere and alamarBlue assays, and cell counts. Demeclocycline also had direct effects in reducing BTIC growth. A global gene expression screen identified several genes, such as DNA damage inducible transcript 4, frizzled class receptor 5 and reactive oxygen species modulator 1, as potential regulators of demeclocycline-mediated BTIC growth reduction. Amongst several tetracycline derivatives, only demeclocycline directly reduced BTIC growth. In summary, we have identified demeclocycline as a novel inhibitor of the growth of BTICs, through direct effect and through indirect stimulation of monocytes. Demeclocycline is a candidate to reactivate compromised immune cells to improve the prognosis of patients with gliomas.

[Genome sequencing of Streptomyces aureofaciens DM-1 and analysis of 6-demethylchlortetracycline biosynthesis gene cluster].

Streptomyces aureofaciens DM-1 is a high-yielding 6-demethylchlortetracycline producer. The genome sequencing of DM-1 reveals a linear chromosome containing 6 824 334 bps nucleotides with GC content of 72.6%. In this genome, a total of 6 431 open reading frames were predicted by using glimmer 3.02, Genemark and Z-Curve softwares. Twenty-eight secondary metabolite biosynthetic gene clusters were uncovered by using AntiSMASH gene prediction software, including the complete 6-demethylchlortetracycline biosynthetic gene cluster. A frame-shift mutation in methyltransferase coding region was detected, which may result in the demethylation of chlortetracycline. The complete genome sequence of S. aureofaciens DM-1 provides basic information for functional genomics studies and selection of high-yielding strains for 6-demethylchlortetracycline.

Genome sequencing of Streptomyces aureofaciens DM-1 and analysis of 6-demethylchlortetracycline biosynthesis gene cluster / 生物工程学报

Streptomyces aureofaciens DM-1 is a high-yielding 6-demethylchlortetracycline producer. The genome sequencing of DM-1 reveals a linear chromosome containing 6 824 334 bps nucleotides with GC content of 72.6%. In this genome, a total of 6 431 open reading frames were predicted by using glimmer 3.02, Genemark and Z-Curve softwares. Twenty-eight secondary metabolite biosynthetic gene clusters were uncovered by using AntiSMASH gene prediction software, including the complete 6-demethylchlortetracycline biosynthetic gene cluster. A frame-shift mutation in methyltransferase coding region was detected, which may result in the demethylation of chlortetracycline. The complete genome sequence of S. aureofaciens DM-1 provides basic information for functional genomics studies and selection of high-yielding strains for 6-demethylchlortetracycline.

Interventions for treating traumatised permanent front teeth: avulsed (knocked out) and replanted.

BACKGROUND: Traumatic dental injuries are common. One of the most severe injuries is when a permanent tooth is knocked completely out of the mouth (avulsed). In most circumstances the tooth should be replanted as quickly as possible. There is uncertainty on which interventions will maximise the survival and repair of the replanted tooth. This is an update of a Cochrane Review first published in 2010. OBJECTIVES: To compare the effects of a range of interventions for managing traumatised permanent front teeth with avulsion injuries. SEARCH METHODS: Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 8 March 2018), Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 2) in the Cochrane Library (searched 8 March 2018), MEDLINE Ovid (1946 to 8 March 2018), and Embase Ovid (1980 to 8 March 2018). The US National Institutes of Health Ongoing Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. SELECTION CRITERIA: We considered randomised and quasi-randomised controlled trials that included a minimum follow-up period of 12 months, for interventions for avulsed and replanted permanent front teeth. DATA COLLECTION AND ANALYSIS: Two review authors independently selected studies, extracted data and assessed the risk of bias. Authors were contacted where further information about their study was required. MAIN RESULTS: Four studies, involving a total of 183 participants and 257 teeth were identified. Each of the interventions aimed to reduce infection or alter the inflammatory response or both at the time of or shortly after the tooth or teeth were replanted. Each study assessed a different intervention and therefore it was not appropriate or possible to numerically synthesise the data. All evidence was rated as being of very low quality due to problems with risk of bias and imprecision of results. This means that we are very uncertain about all of the results presented in this review.One study at high risk of bias with 69 participants (138 teeth) compared a 20-minute soak with gentamycin sulphate for both groups prior to replantation with the experimental group receiving daily hyperbaric oxygen for 80 minutes for the first 10 days. There was some evidence of a benefit for the hyperbaric oxygen group in respect of periodontal healing, tooth survival, and pulpal healing.One study at unclear risk of bias with 22 participants (27 teeth) compared the use of two root canal medicaments, Ledermix and Ultracal. There was insufficient evidence of a difference for periodontal healing or tooth survival. This was the only study to formally report adverse events with none identified. Study authors reported that Ledermix caused a greater level of patient dissatisfaction with the colour of avulsed and replanted teeth.A third study at high risk of bias with 19 participants compared extra- or intra-oral endodontics for avulsed teeth which were stored dry for longer than 60 minutes before replantation. There was insufficient evidence of a difference in periodontal healing.The fourth study at high risk of bias with 73 participants compared a 10-minute soak in either thymosin alpha 1 or saline before replantation followed by daily gingival injections with these same medicaments for the first 7 days. There was some evidence of a benefit for thymosin alpha 1 with respect to periodontal healing and tooth survival. AUTHORS' CONCLUSIONS: Based on the results of the included studies, there is insufficient evidence to support or refute the effectiveness of different interventions for avulsed and replanted permanent front teeth. The overall quality of existing evidence was very low, and therefore great caution should be exercised when generalising the results of the included trials. There is urgent need for further well-designed randomised controlled trials.

Comparative efficacy of endodontic medicaments and sodium hypochlorite against Enterococcus faecalis biofilms.

BACKGROUND: Many studies have investigated the effectiveness of root canal irrigants and medicaments against Enterococcus faecalis. The aim of this study was to compare the efficacy of commonly used medicaments against E. faecalis cultured as a biofilm on dentine substrate. METHODS: An E. faecalis biofilm was established on human dentine slices using a continuous flow cell. Each test medicament (Ledermix, Ca(OH)2 , Odontopaste, 0.2% chlorhexidine and 50:50 combinations of Ledermix/Ca(OH)2 and Odontopaste/Ca(OH)2 ) was introduced into the flow cell and biofilms were harvested and quantitated by determining cellular protein. Cellular viability was determined using serial plating and the number of colony-forming units was normalized against cellular protein to allow treatment protocols to be compared. Qualitative scanning electron microscopy analyses of the biofilm were performed after a 48-h exposure to each test agent. RESULTS: Sodium hypochlorite achieved total bacterial elimination. Ledermix and Odontopaste had no significant effect on the E. faecalis biofilm. Ca(OH)2 and 50:50 combinations of Ca(OH)2 /Ledermix or Ca(OH)2 /Odontopaste reduced the viability by more than 99% while 0.2% chlorhexidine reduced bacterial numbers by 97%. CONCLUSIONS: Sodium hypochlorite remains the gold standard for bacterial elimination in root canal therapy. However, Ca(OH)2 in isolation and combined with Ledermix, and Odontopaste was highly effective in reducing bacterial viability.

TAR cloning and integrated overexpression of 6-demethylchlortetracycline biosynthetic gene cluster in Streptomyces aureofaciens.

6-Demethylchlortetracycline (6-DCT), a tetracycline antibiotic produced by Streptomyces aureofaciens, is a crucial precursor employed for the semi-synthesis of tigecycline, minocycline, and amadacyclin (PTK 0796). In this study, the 6-DCT biosynthetic gene cluster (BGC) was cloned from genomic DNA of a high 6-DCT-producing strain, S. aureofaciens DM-1, using the transformation-associated recombination method. An extra copy of the 6-DCT BGC was introduced and integrated into the chromosome of S. aureofaciens DM-1. Duplication of the 6-DCT BGC resulted in a maximum increase of the 6-DCT titer by 34%.

Improving care and outcomes of inpatients with syndrome of inappropriate antidiuresis (SIAD): a prospective intervention study of intensive endocrine input vs. routine care.

PURPOSE: The syndrome of inappropriate antidiuresis is often undertreated with most patients discharged with persistent hyponatraemia. This study tested the hypothesis that an endocrine input is superior to routine care in correcting hyponatraemia and can improve patient outcomes. METHODS: This single-centre prospective-controlled intervention study included inpatients admitted at a UK teaching hospital, with serum sodium ≤ 127 mmol/l, due to syndrome of inappropriate antidiuresis over a 6-month period. The prospective intervention group (18 subjects with mean serum sodium 120.7 mmol/l) received prompt endocrine input, while the historical control group (23 patients with mean serum sodium 124.1 mmol/l) received routine care. The time needed for serum sodium increase ≥ 5 mmol/l was the primary endpoint. RESULTS: The intervention group achieved serum sodium rise by ≥5 mmol/l in 3.5 vs. 7.1 days in the control group (P = 0.005). In the intervention group, the mean total serum sodium increase was 12 mmol/l with only 5.8 % of patients discharged with serum sodium < 130 vs. 6.3 mmol/l increase (P < 0.001) and 42.1 % of the subjects discharged with serum sodium < 130 mmol/l in the control group (P = 0.012). The mean length of hospital stay in the intervention group (10.9 days) was significantly shorter than in the control group (14.5 days; P = 0.004).The inpatient mortality rate was 5.5 % in intervention arm vs. 17.4 % in control arm, but this difference was not statistically significant. CONCLUSIONS: Since the endocrine input improved time for correction of hyponatraemia and shortened length of hospitalisation, widespread provision of endocrine input should be considered.

Variable patterns of ectopic mineralization in Enpp1asj-2J mice, a model for generalized arterial calcification of infancy.

Generalized arterial calcification of infancy (GACI) is an autosomal recessive disorder characterized by early onset of extensive mineralization of the cardiovascular system. The classical forms of GACI are caused by mutations in the ENPP1 gene, encoding a membrane-bound pyrophosphatase/phosphodiesterase that hydrolyzes ATP to AMP and inorganic pyrophosphate. The asj-2J mouse harboring a spontaneous mutation in the Enpp1 gene has been characterized as a model for GACI. These mutant mice develop ectopic mineralization in skin and vascular connective tissues as well as in cartilage and collagen-rich tendons and ligaments. This study examined in detail the temporal ectopic mineralization phenotype of connective tissues in this mouse model, utilizing a novel cryo-histological method that does not require decalcification of bones. The wild type, heterozygous, and homozygous mice were administered fluorescent mineralization labels at 4 weeks (calcein), 10 weeks (alizarin complexone), and 11 weeks of age (demeclocycline). Twenty-four hours later, outer ears, muzzle skin, trachea, aorta, shoulders, and vertebrae were collected from these mice and examined for progression of mineralization. The results revealed differential timeline for disease initiation and progression in various tissues of this mouse model. It also highlights the advantages of cryo-histological fluorescent imaging technique to study mineral deposition in mouse models of ectopic mineralization disorders.

Pregnancy and lactation period: Which antibiotic and rinsing solutions? / Grossesse et allaitement: antibiotiques, solutions de rinçage de bouche et pâtes ou pommades

The aim of this paper is to show aspects of dental treatment in pregnancy. The reader should gain security in the election of the proper drugs for antibiotic therapy and rinsing solutions. Antibiotics as penicillins are the first choice in case of dental infections in pregnancy. In allergic patients, macrolides may be an alternative. Wound and mouth rinsing solutions containing chlorhexidine should be preferred in pregnancy. Ledermix(®) in endodontic treatment should be avoided in the pregnant woman. Solcoseryl(®) can be used for wound healing. Elective dental procedures should be postponed after delivery and after lactation period.

Pregnancy and lactation period: Which antibiotic and rinsing solutions? / Schwangerschaft und Stillzeit: Antibiotika, Spülungen und Pasten

The aim of this paper is to show aspects of dental treatment in pregnancy. The reader should gain security in the election of the proper drugs for antibiotic therapy and rinsing solutions. Antibiotics as penicillins are the first choice in case of dental infections in pregnancy. In allergic patients, macrolides may be an alternative. Wound and mouth rinsing solutions containing chlorhexidine should be preferred in pregnancy. Ledermix(®) in endodontic treatment should be avoided in the pregnant woman. Solcoseryl(®) can be used for wound healing. Elective dental procedures should be postponed after delivery and after lactation period.

Influence of the bleaching interval on the luminosity of long-term discolored enamel-dentin discs.

OBJECTIVES: The aim of this study is to investigate the influence of changing the sodium perborate-tetrahydrate (PBS-4) at a 4-day interval versus no change after 16 days of internal bleaching. MATERIALS AND METHODS: Two hundred and ten bovine enamel-dentin discs were discolored for 3.5 years with 14 different endodontic materials. All groups with a discoloring index of ∆E (mean) ≥ 5.5 were included in the present investigation: ApexCal (APCA), MTA white + blood (WMTA+BL), Portland cement + blood (PC+BL), blood (BL), MTA gray (GMTA), MTA gray + blood (GMTA+BL), Ledermix (LED), and triple antibiotic paste containing minocycline (3Mix). Fourteen specimens of each group were randomly assigned into two treatment groups: (1) no change of the PBS-4 (n = 7); (2) change of the PBS-4 every 4 days (n = 7). Color measurements were taken at 10 different time intervals and the L*a*b* values were recorded with a spectrophotometer (VITA Easyshade® compact). RESULTS: In the group 3Mix, significantly better results were achieved by changing the bleaching agent every 4 days (P = 0.0049; q = 0.04), while the group WMTA+BL indicated better results by no change of the bleaching agent (P = 0.0222, q = 0.09). All remaining groups showed no statistical difference between the two treatment procedures. CONCLUSIONS: Moderate discolorations can be successfully treated without changing the bleaching agent over a period of 16 days. Changing the sodium perborate-tetrahydrate every 4 days is preferred in case of severe discolored enamel-dentin discs only. CLINICAL RELEVANCE: This approach may offer a reduced number of clinical appointments and a secondary cost reduction to the patient.

Evidence for the use of demeclocycline in the treatment of hyponatraemia secondary to SIADH: a systematic review.

AIMS: Hyponatraemia (HN) is the most common electrolyte balance disorder in clinical practice. Since the 1970s, demeclocycline has been used in some countries to treat chronic HN secondary to syndrome of inappropriate antidiuretic hormone secretion (SIADH). The precise mechanism of action of demeclocycline is unclear, but has been linked to the induction of nephrogenic diabetes insipidus. Furthermore, the safety profile of demeclocycline is variable with an inconsistent time to onset, and a potential for complications. There has been no systematic evaluation of the use of demeclocycline for the treatment of HN secondary to SIADH to date. A systematic literature review was performed to obtain an insight into the clinical safety and efficacy of demeclocycline for this condition. METHODS: Embase(™) , MEDLINE(®) , MEDLINE(®) In-Process, and The Cochrane Library were searched on two occasions using MeSH terms combined with free-text terms. References were screened by two independent reviewers. Relevant publications were then extracted by two independent reviewers, with a third reviewer collating and finalising extractions. RESULTS: The searches returned a total of 705 hits. 632 abstracts were screened after the removal of duplicates. Following screening, 35 full-length publications were reviewed. Of these, 17 were excluded, resulting in 18 studies deemed relevant for data extraction. Two were randomised controlled trials (RCTs), 16 were non-RCTs, and 10 were case reports. DISCUSSION: Although most reports suggest that demeclocycline can address serum sodium levels in specific patients with HN, efficacy is variable, and may depend upon the underlying aetiology. Demeclocycline dose adjustments can be complex, and as its use in clinical practice is not well defined, it can differ between healthcare professionals. CONCLUSION: There is a lack of clinical and economic evidence supporting the use of demeclocycline for HN secondary to SIADH. Patients receiving demeclocycline for HN secondary to SIADH must be closely monitored.

The diagnosis and management of inpatient hyponatraemia and SIADH.

BACKGROUND: Hyponatraemia is a very common medical condition that is associated with multiple poor clinical outcomes and is often managed suboptimally because of inadequate assessment and investigation. Previously published guidelines for its management are often complex and impractical to follow in a hospital environment, where patients may present to divergent specialists, as well as to generalists. DESIGN: A group of senior, experienced UK clinicians, met to develop a practical algorithm for the assessment and management of hyponatraemia in a hospital setting. The latest evidence was discussed and reviewed in the light of current clinical practicalities to ensure an up-to-date perspective. An algorithm was largely developed following consensus opinion, followed up with subsequent additions and amendments that were agreed by all authors during several rounds of review. RESULTS: We present a practical algorithm which includes a breakdown of the best methods to evaluate volume status, simple assessments for the diagnosis of the various causes and a straightforward approach to treatment to minimise complexity and maximise patient safety. CONCLUSION: The algorithm we have developed reflects the best available evidence and extensive clinical experience and provides practical, useable guidance to improve patient care.