The Effect of Doxycycline on the Expression of MMP-2 and MMP-9 in Multiple Myeloma / 中国实验血液学杂志

OBJECTIVE@#To investigate the expression of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) in multiple myeloma (MM) patients, and analyze the effect of doxycycline (DOX) on the expression of MMP-2 and MMP-9 in MM cells.@*METHODS@#The peripheral blood and bone marrow samples of MM patients were collected, and the patients were divided into three groups: newly diagnosed group, remission group and relapsed/refractory group, while the peripheral blood samples of 34 health people and the bone marrow samples of 17 IDA patients were selected as normal control and control group. The levels of MMP-2 and MMP-9 were detected by ELISA. The protein levels of MMP-2 and MMP-9 in H929 cells treated by different concentrations of DOX were analyzed by Western blot. After H929 cells was treated by Akt inhibitor MK-2206 2HCl in combination with DOX, Western blot was used to detect the levels of MMP-2 and MMP-9.@*RESULTS@#The levels of MMP-2 and MMP-9 in newly diagnosed MM patients were higher than those in control (P<0.05), while for the patients in the remission group were decreased, but still higher than those in control. The levels of MMP-2 and MMP-9 were increased again for the patients in relapsed/refractory group, and showed no significant difference as compared with those in newly diagnosed group. The levels of MMP-2 and MMP-9 could be inhibited by 10 mg/L and 15 mg/L DOX treated by H929 cell. The protein levels of MMP-2 and MMP-9 showed no altered in H929 cells treated by 5 nmol/L MK-2206 2HCl alone. DOX exerted more profound inhibitory effect to MMP-2 and MMP-9 expression in H929 cells when Akt inhibitor MK-2206 2HCl was combined with DOX.@*CONCLUSION@#The levels of MMP-2 and MMP-9 are increased in MM patients and related to the disease status of MM. DOX can inhibit the expression of MMP-2 and MMP-9 in MM cells, and antagonizing its activation of Akt signaling pathway can further enhance the inhibitory effect.

Effect of Doxycycline on Intrinsic Apoptosis of Myeloma Cell Line H929 and Its Mechanism / 中国实验血液学杂志

OBJECTIVE@#To investigate the mechanism of the in vitro toxicity of doxycycline to myeloma cell line H929 and also the possible pathway involved its toxicity.@*METHODS@#Myeloma cell line H929 was treated with DOX, MEK inhibitor U0126 or RAS agonist ML-098, either alone or in combination. Then, the expression of p-MEK, caspase-3, caspase-9 and c-Jun in H929 were used to detected by Western blot; the cells proliferation and apoptosis were detected by CCK-8 assay and flow cytometry, respectively.@*RESULTS@#DOX significantly increased the levels of cleaved caspase-3 and caspase-9, and down-regulated the level of p-MEK in H929 (P<0.05). MEK antagonist U0126 significantly increased the levels of cleaved caspase-3 and caspase-9, and down-regulated the level of p-MEK (P<0.05). After Dox combined with ML-098 treatment of H929 cells, the apoptosis rate of H929 cells was lower than that of DOX alone treatment group(P<0.05). Compared with DOX alone treatment group, the expressions of p-MEK and p-ERK1/2 in DOX+ML-098 combined treatment group were increased, and the levels of cleaved caspase-3,9 in H929 cells were decreased (P<0.05). The levels of c-Jun mRNA and protein increased in H929 when treated by DOX alone (P<0.05).@*CONCLUSION@#DOX can induce apoptosis of H929 via intrinsic apoptosis pathway, and MEK/ERK pathway and c-Jun possibly play a role in this process.

Effects of combined oral doxycycline and topical cyclosporine treatment on ocular signs, symptoms, and tear film parameters in rosacea patients / Efeitos da doxiciclina oral combinada e tratamento tópico com ciclosporina nos sinais e sintomas oculares e em parâmetros do filme lacrimal em pacientes com rosácea ocular

ABSTRACT Purpose: This study reports the effects of combined use of oral doxycycline and topical cyclosporine on ocular signs, symptoms, and tear film parameters in rosacea patients. Methods: Fifty-four right eyes of 54 patients were included in this study. All patients underwent full ophthalmologic examination-including best corrected visual acuity measurement, slit-lamp anterior segment and fundus examination, tear film break-up time, and Schirmer test-before treatment and six months post-treatment. Patients were divided into two treatment groups. The first group was treated with oral doxycycline 100 mg twice daily for the first month and once daily for the following two months. The second group received topical 0.05% cyclosporine emulsion drops twice daily for six months in addition to the oral doxycycline treatment regimen. All patients received preservati ve-free artificial tear drops, warm compress, eyelash cleaning, and topical corticosteroid drops three times daily for one month. Results: A significant improvement in ocular signs and symptoms was recorded for all patients in groups 1 and 2 after treatment. There was not a significant difference in terms of itching, burning, meibomian gland inspissation, corneal neovascularization, and conjunctival hyperemia score changes between groups 1 and 2. The increases in Schirmer test and break-up time scores were significantly higher in group 2 than in group 1. Conclusions: Our results support the finding that topical cyclosporine in addition to the standard regimen improves tear function, as shown by Schirmer test and break-up time scores, in ocular rosacea patients.

RESUMO Objetivo: Este estudo relata os efeitos do uso combinado de doxiciclina oral e ciclosporina tópica sobre sinais e sintomas oculares e sobre parâmetros do filme lacrimal em pacientes com rosácea. Métodos: Cinquenta e quatro olhos direitos de 54 pacientes foram incluídos no estudo. Todos os pacientes foram submetidos a exame oftalmológico completo - incluindo a melhor medida da acuidade visual corrigida, segmento anterior em lâmpada de fenda e exame de fundo de olho, tempo de ruptura do filme lacrimal e teste de Schirmer - antes do tratamento e após seis meses de tratamento. O primeiro grupo foi tratado com doxiciclina oral 100 mg duas vezes ao dia no primeiro mês e uma vez ao dia nos dois meses seguintes. O segundo grupo recebeu gotas tópicas de emulsão de ciclosporina a 0,05% duas vezes ao dia por seis meses, além do tratamento com doxiciclina por via oral. Todos os pacientes receberam gotas de lágrima artificial sem conservantes, compressas mormas, limpeza de cílios e gotas de corticosteróide tópico três vezes ao dia durante um mês. Resultados: Uma melhora significativa nos sinais e sintomas oculares foi registrada para todos os pacientes do grupo 1 e 2 após o tratamento. Não houve diferença significativa em termos de prurido, queimação, inspeção da glândula meibomiana, neovascularização da cór nea e alterações na pontuação da hiperemia conjuntival entre os grupos 1 e 2. O teste de Schirmer e o aumento do tempo de ruptura no grupo 2 foram significativamente maiores do que no grupo 1. Conclusões: Os autores concluíram que os resultados apoiam a descoberta de que a ciclosporina tópica, além do tratamento padrão, melhora a função lacrimal como demonstrado pelo teste de Schirmer e o tempo de ruptura em pacientes com rosácea ocular.

Doxycycline-containing glass ionomer cement for arresting residual caries: an in vitro study and a pilot trial

Abstract In a previous study, we demonstrated that the incorporation of doxycycline hyclate (DOX) into resin-modified glass ionomer cement (RMGIC) inhibited important cariogenic microorganisms, without modifying its biological and mechanical characteristics. In this study, we keep focused on the effect of that experimental material as a potential therapy for arresting residual caries by analyzing other in vitro properties and conducting a pilot clinical trial assessing the in vivo effect of DOX-containing RMGIC on residual mutans streptococci after partial carious removal in primary molars. Specimens of the groups RMGIC (control); RMGIC + 1.5% DOX; RMGIC + 3% DOX; and RMGIC + 4.5% DOX were made to evaluate the effect of DOX incorporation on surface microhardness and fluoride release of RMGIC and against biofilm of Streptococcus mutans. Clinical intervention consisted of partial caries removal comparing RMGIC and RMGIC + 4.5% DOX as lining materials. After 3 months, clinical and microbiologic evaluations were performed. Data were submitted to ANOVA/Tukey or Wilcoxon/Mann-Whitney set as α=0.05. Fluoride release and surface microhardness was not influenced by the incorporation of DOX (p>0.05). There was a significant reduction of S. mutans biofilm over the material surface with the increase of DOX concentration. After clinical trial, the remaining dentin was hard and dry. Additionally, mutans streptococci were completely eliminated after 3 months of treatment with RMGIC + 4.5% DOX. The incorporation of DOX provided better antibiofilm effect, without jeopardizing fluoride release and surface microhardness of RMGIC. This combination also improved the in vivo shortterm microbiological effect of RMGIC after partial caries removal.

Mechanistic effect of the human GJB6 gene and its mutations in HaCaT cell proliferation and apoptosis

We constructed lentiviral vectors containing the human wild-type GJB6 gene and the mutant variants A88V and G11R. The three proteins were stably expressed by the Tet-on system in the HaCaT cell line and used to study the functional effect of the variants. The CCK-8 assay and flow cytometric analyses were used to determine the levels of cell proliferation and apoptosis. Western blot analyses were performed to analyze the relevant clinical indicators of hidrotic ectodermal dysplasia and markers of apoptosis in transfected HaCaT cells. The CCK8 assay and the flow cytometry results showed a significant increase (P<0.05) in the apoptosis of HaCaT cells expressing the A88V and G11R mutants. In addition, we demonstrated that the A88V and G11R mutants induced the apoptosis of transfected HaCaT cells via the activation of caspase-3, -8, -9, and PARA. No change was observed in the activity of BAX compared with the control. This study provides further clarification on the mechanisms underlying the effect of the mutant variants A88V and G11R of the GJB6 gene on the induction of HaCaT cell apoptosis.

effect of four commonly used root conditioner agents in different time periods applied on periodontally diseased and healthy teeth

Statement of Problem: Root surface contamination or infection can potentially change the consequences of regenerative periodontal therapies and therefore the modification and disinfection of the contaminated root surfaces are necessary

Objectives: This study aimed to compare the surface characteristics of the extracted human teeth after exposure to four root conditioners in different time periods

Materials and Methods: The study samples were prepared from 40 freshly extracted teeth including 20 affected teeth with periodontal diseases and 20 healthy teeth. After performing root planning, 240 dentinal block samples were prepared and each affected and healthy sample was randomly allocated to receive one of the following root conditioners; Ethylenediaminetetraaceti acid [EDTA], citric acid, doxycycline, and tetracycline or rinsed with normal saline as the control agent. The prepared specimens were evaluated using scanning electron microscope and the inter-group differences and changes in study indices; dentin [%], tubular spaces [%], and diameter of dentinal tubules [micro m[2]] were compared using one-way ANOVA test

Results: In the control group receiving normal saline, the changes in the indicators of dentin, tubular spaces, and diameter of dentinal tubules remained insignificant in all time periods. EDTA, citric acid, and tetracycline had chelating effects on the study indices; however, doxycycline led to gradual decrease of the tubular space and diameter as well as increase in dentin percentage

Conclusions: In different time intervals and when considering healthy or affected tooth surfaces, the effect of conditioning agents could be different. Amongst the four agents used, EDTA and tetracycline consistently increased the diameter of tubules and percentage of patent tubules in both healthy and diseased teeth

Propuesta de reformas a los prestadores públicos de servicios médicos en Chile: “fortaleciendo la opción pública” / A reform proposal to strengthen public health care

Currently, there is no discussion on the need to improve and strengthen the institutional health care modality of FONASA (MAI), the health care system used by the public services net and by most of the population, despite the widely known and long lasting problems such as waiting lists, hospital debt with suppliers, lack of specialists and increasing services purchase transference to the private sector, etc. In a dichotomous sectorial context, such as the one of health’s social security in Chile (the state on one side and the market on the other), points of view are polarized and stances tend to seek refuge within themselves. As a consequence, to protect the public solution is commonly associated with protecting the “status quo”, creating an environment that is reluctant to change. The author proposes a solution based on three basic core ideas, which, if proven effective, can strengthen each other if combined properly. These are: network financing management, governance of health care services in MAI and investments and human resources in networked self-managed institutions. The proposal of these core ideas was done introducing a reality testing that minimizes the politic complexity of their implementation.

Low concentrations of doxycycline attenuates FasL-induced apoptosis in HeLa cells

BACKGROUND: Doxycycline (DC) has been shown to possess non-antibiotic properties including Fas/Fas Ligand (FasL)-mediated apoptosis against several tumor types in the concentration range of 10-40 µg/mL. However, the effect of DC in apoptotic signaling at much low concentrations was not studied. METHODS: The present study investigated the attenuation effect of low dose of DC on FasL-induced apoptosis in HeLa cell by the methods of MTT assay, fluorescence microscopy, DNA fragmentation, flow cytometry analysis, and western blotting. RESULTS AND CONCLUSION: In the present findings we showed that low concentration of DC (<2.0 µg/mL) exhibited protective effects against FasL-induced apoptosis in HeLa cells. FasL treatment to HeLa cells resulted in a concentration-dependent induction of cell death, and treatment with low concentrations of DC (0.1-2 µg/mL) significantly (p < 0.001) attenuated the FasL-induced cell death as measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazo-lium bromide (MTT) assay. Further, the FasL-induced apoptotic features in HeLa cells, such as morphological changes, DNA fragmentation and cell cycle arrest was also inhibited by DC (0.5 µg/mL). Tetracycline and minocycline also showed similar anti-apoptotic effects but were not significant when compared to DC, tested at same concentrations. Further, DC (0.01-16 µg/mL) did not influence the hydrogen peroxide- or cisplatin-induced intrinsic apoptotic pathway in HeLa cells. Protein analysis using Western blotting confirmed that FasL-induced cleavage/activation of cas-pase-8 and caspase-3, were inhibited by DC treatment at low concentration (0.5 µg/mL). Considering the overall data, we report for the first time that DC exhibited anti-apoptotic effects at low concentrations in HeLa cells by inhibition of caspase activation via FasL-induced extrinsic pathway.

Assessment of Bone Healing in Rabbit Calvaria Grafted with Three Different Biomaterials

This study evaluated the bone regeneration process in rabbit calvaria induced by three types of biomaterials: two xenogenous, consisting of deproteinized bovine bone, while the other was alloplastic, based on biphasic calcium phosphate. Five New Zealand white rabbits weighing between 2,900 and 3,500 g were submitted to four standard 8 mm-diameter perforations at the parietal bone. Three perforations were filled with three grafts and biomaterials, two of them received bovine Bio-Oss(r) and Endobon(r) Xenograft Granules, and the other consisted of fully alloplastic Straumann(r) Bone Ceramic. The fourth remaining cavity was used as control with coagulum. After eight weeks, the animals were sacrificed, and the samples were prepared for morphometric and qualitative analysis. The cavities filled with alloplastic biomaterials showed higher percentages of newly formed bone (p<0.05), while the cavities with xenogenous biomaterials showed higher amount of residual graft (p<0.05). Although the results showed greater bone formation with Straumann(r) Bone Ceramic, further studies are required to prove which is the more effective biomaterial for bone induction process.

Este estudo avaliou o processo de reparação óssea induzida por três biomateriais, dois de origem xenógena constituído de osso bovino desproteinizado e um aloplástico à base de fosfato de cálcio bifásico, em calota craniana de coelhos. Em cinco coelhos brancos da Nova Zelândia com peso entre 2.900 e 3.500 g, foram realizadas quatro perfurações padronizadas de 8 mm de diâmetro nos ossos parietais e enxertados dois biomateriais de origem bovina: Bio-Oss(r) e Endobon(r) Xenograft Granules e um totalmente aloplástico: Straumann(r)Bone Ceramic. Uma cavidade permaneceu com coágulo e foi utilizado como controle. Após oito semanas os animais foram sacrificados e as amostras preparadas para análise morfométrica e qualitativa. Os resultados mostraram que as cavidades preenchidas com o biomaterial aloplástico apresentaram percentualmente maior quantidade de osso neoformado (p<0,05). Apesar dos resultados mostrarem maior neoformação óssea pelo Straumann(r)Bone Ceramic, há a necessidade de mais estudos para se comprovar qual biomaterial é mais efetivo no processo de indução óssea.

Doxiciclina em pacientes com linfangioleiomiomatose: segurança e eficácia no bloqueio de metaloproteinases / Doxycycline use in patients with lymphangioleiomyomatosis: safety and efficacy in metalloproteinase blockade

OBJETIVO: A linfangioleiomiomatose (LAM) é caracterizada pela presença de cistos pulmonares, cuja formação está associada à hiperreatividade de metaloproteinases de matriz (MMP), principalmente MMP-2 e MMP-9. Objetivamos comparar os níveis dessas MMPs entre pacientes com LAM e controles saudáveis, assim como avaliar, nas pacientes com LAM, a segurança e a eficácia do tratamento com doxiciclina, um potente inibidor de MMPs. MÉTODOS: Estudo clínico prospectivo no qual as pacientes com LAM receberam doxiciclina (100 mg/dia) por seis meses, coletando-se amostras de urina e sangue para a dosagem de MMP-2 e MMP-9 antes e ao final do período. Foram ainda obtidas amostras de 10 mulheres saudáveis. RESULTADOS: De 41 pacientes com LAM que iniciaram o tratamento, 34 concluíram o protocolo. Os níveis de MMP-9 sérica e urinária foram significativamente inferiores no grupo controle (p < 0,0001). Comparando-se os valores antes e após o tratamento, a mediana do nível sérico da MMP-9 reduziu de 919 ng/mL para 871 ng/mL (p = 0,05), enquanto a mediana da dosagem urinária de MMP-9 diminui de 11.558 pg/mL para 7.315 pg/mL (p = 0,10). A mediana da MMP-2 sérica apresentou um decréscimo significativo após o tratamento (p = 0,04). Não foram detectados níveis de MMP-2 urinária. Epigastralgia, náuseas e diarreia foram os efeitos adversos mais prevalentes, e geralmente autolimitados. Apenas 1 paciente interrompeu o tratamento devido a efeitos colaterais. CONCLUSÕES: Pela primeira vez, conseguiu-se evidenciar em pacientes com LAM a redução dos níveis séricos e urinários de MMPs após o uso de doxiciclina, que se mostrou uma medicação segura, com efeitos colaterais leves e toleráveis.

OBJECTIVE: Lymphangioleiomyomatosis (LAM) is characterized by lung cysts, whose development is associated with matrix metalloproteinase (MMP) hyperactivity, principally that of MMP-2 and MMP-9. Our objective was to compare LAM patients and controls in terms of the levels of these MMPs, as well as to determine the safety and efficacy of treatment with doxycycline, a potent MMP inhibitor. METHODS: Prospective clinical study involving female LAM patients who received doxycycline (100 mg/day) for six months. Urine and blood samples were collected for the quantification of MMP-2 and MMP-9 before and after the treatment period. Samples from 10 healthy women were also collected. RESULTS:Of the 41 LAM patients who started the treatment, 34 completed the protocol. Serum and urinary MMP-9 levels were significantly lower in the controls than in the LAM patients (p < 0.0001). Comparing pre- and post-treatment values, we found that the median level of MMP-9 in serum decreased from 919 ng/mL to 871 ng/mL (p = 0.05), whereas that of MMP-9 in urine decreased from 11,558 pg/mL to 7,315 pg/mL (p = 0.10). After treatment, the median level of MMP-2 in serum was significantly lower (p = 0.04) and urinary MMP-2 levels were undetectable. Nausea, diarrhea, and epigastric pain were the most prevalent adverse affects and were often self-limiting. There was only one case in which the patient discontinued the treatment because of side effects. CONCLUSIONS: We have demonstrated, for the first time, a decrease in serum and urine levels of MMPs in LAM patients treated with doxycycline, which proved to be a safe medication, with mild and well-tolerated side effects.

In vitro synergistic effect of doxycycline & ofloxacin in combination with ethanolic leaf extract of Vangueria spinosa against four pathogenic bacteria.

Background & objectives: The in vitro antibacterial activity of ethanolic leaf extract of Vangueria spinosa Roxb. (Rubiaceae) alone and in combination with antibiotics (doxycycline and ofloxacin) by means of fractional inhibitory concentration indices (FICI) as well as by the use of time-kill assays against one Gram-positive bacterium (Staphylococcus aureus) and three Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) was studied. Methods: Antibacterial activity was assayed by using the microdilution method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for the ethanolic leaf extract of V. spinosa alone and also in combination with antibiotics using the fractional inhibitory concentration (FIC) and time-kill assay method. Synergism was also tested using checker board dilution method. Results: MIC/MBC values for ethanolic leaf extract of V. spinosa against all the tested bacteria ranged between 25.5 - 52.6/22.4 - 60.5 μg/ml, for doxycycline 4.0/4.0 - 4.5 μg/ml and for ofloxacin 0.625 - 2.5/1. 25 - 5.0 μg/ml respectively. The average log reduction in viable cell count in time-kill assay ranged between 2.4 log10 - 4.5 log10 cfu/ml after 1 h of interaction and between 3.9 log10 -5.0 log10 cfu/ml after 3 h interaction in 1 × MIC to 4 × MIC. When leaf extract and antibiotics were combined, the average log reduction in viable cell count for doxycycline from 1.5 log10 - 5.18 log10 cfu/ml and for ofloxacin 3.06 log10- 5.39 log10 cfu/ml. Synergistic actions were observed in all the cases except against P. aeruginosa which showed an additive effect for ofloxacin and plant extract combination. Interpretation & conclusions: This study provides a preliminary report of synergistic activity of V. spinosa Roxb, ethanolic leaf extract with antibiotics.

Antimicrobial effect of MTAD, Tetraclean, Cloreximid, and sodium hypochlorite on three common endodontic pathogens.

Objectives: The aim of this in vitro study was to evaluate the antimicrobial action of BioPure MTAD (Dentsply Tulsa Dental, Johnson City, TN), Tetraclean, Cloreximid (a mixture of Chlorhexidine (CHX) digluconate and Cetrimide), and 5.25% NaOCl (Ogna Laboratori Farmaceutici, Milano, Italy) against selected endodontic pathogens (Enterococcus faecalis, Porphyromonas gingivalis, and Prevotella intermedia). Materials and Methods: The agar plate diffusion procedure was used to observe the antimibrobial activity of irrigants. Results: Statistical analysis revealed significant effects of the different irrigants on the bacteria colonies. Treatment with 5.25% NaOCl induced a larger zone of microbial inhibition in Prevotella intermedia and Porphyromonas gingivalis (Tukey HSD post-test, P = 0.0001) when compare to MTAD, Tetraclean and CHX. Anyway, MTAD and Tetraclean were more effective to inhibit bacterial growth compared to CHX (P < 0.0001, Tukey HSD post-test). Furthermore, post hoc analysis revealed that MTAD and Tetraclean induced the largest zone of microbial inhibition of Enterococcus faecalis cultured under both aerobic and anaerobic conditions, when compared with 2% CHX and NaOCl (P < 0.0001, Tukey HSD post-test). The control group showed no microbial inhibition. Conclusion: 5.25% NaOCl showed a high antimicrobial activity against anaerobic bacteria. MTAD and Tetraclean showed a high action against both, strictly anaerobic and facultative anaerobic bacteria. Chlorexidine + Cetrimide (Cloreximid) showed the lowest antibacterial activity against both, facultative and strictly anaerobic bacteria tested.

Incidencia, diagnóstico, manejo y evolución de las neumonías atípicas en el Hospital Militar Cap. (Av) Guillermo Hernández Jacobsen: enero 1999-mayo 2006 / Incidence, diagnosis, management and development of atypical pneumonia at the Military Hospital Cap. (Av)Guillermo Hernández Jacobsen: january 1999-may 2006

Se realiazó un estudio descriptivo, retrospectivo y observacional mediante la revisión de 35 historias médicas de pacientes hospitalizados con Neumonía Atípica entre enero de 1999 y mayo de 2006. El grupo etáreo más afectado fue el de 15 a 39 años de edad, que representa el 54.2 por ciento. Los síntomas más frecuentes fueron de origen respiratorio, como son tos (32.5 por ciento) y disnea (26.25 por ciento). El 22.8 por ciento resultó positivo para Mycoplasma y el 20 por ciento para Chlamydia. Al momento del ingreso, se manejó con amtibioticoterapia basada en Levofloxacina en un 29.7 por ciento. Claritromicina en un 16.2 por ciento. Se observo evolución satisfactoria en el 82.8 por ciento de los casos en estudio.

effect of minocycline, doxycycline and tetracycline on plaque bacteria associated with periodontitis

The aim of this study was to evaluate the antibacterial activity of three antibiotics, Minocycline, Tetracycline and Doxycycline against the representative strains of plaque bacteria, particularly of species related to periodontitis. Nineteen strains of bacteria isolated from human periodontal pockets were used as test organism with B fragalis as control, all strains were maintained in 20 ml of Brain Heart inforsin at 37°C and subcultured weekly. Three antibiotics Minocycline, Tetracycline and Doxycycline were tested against these bacteria minimum inhibitory concentration was taken as the lowest antibiotic concentration that yield no visible growth. Of the 3 antibiotics, minocycline invariably showed a lower minimum inhibitory concentration, than tetracycline or doxycycline. The gram-negative organisms involved in adult periodontitis including those organism with localized juvenile periodontitis were most susceptible to minocycline at a lower concentration than tetracycline and doxycycline. This indicates that minocycline is likely to be a good choice for antibiotic treatment and prevention of periodontal inflammation in which these organisms are implicated

Endosymbiotic Wolbachia of parasitic filarial nematodes as drug targets.

The parasitic nematodes Wuchereria bancrofti, Brugia malayi and B. timori cause a dreadful disease in humans known as lymphatic filariasis, which afflicts more than 120 million people worldwide. As per recent epidemiologic estimates on prevalence of W. bancrofti and B. malayi, about 428 million people are at risk, with 28 million microfilaria carriers and 21 million clinical cases spread out in 13 States and 5 Union Territories of India. The Indian subcontinent that comprises Bangladesh, India, Maldives, Nepal and Sri Lanka harbours 50 per cent of the world's lymphatic filarial disease burden. Recently, an endobacterium of Wolbachia species that belongs to the family Rickettsiaceae was found in all life cycle stages of these nematodes and the transmission is exclusively vertical through the embryonic stages of the female worms. People with filariasis have been exposed to these Wolbachia bacteria or their proteins by the natural killing of parasites. Wolbachia have also been identified occasionally in body fluids of infected patients. Evidence suggests that these Wolbachia are mutualistic symbionts and can be cured from the nematodes by several antibiotics having antirickettsial properties. Treatment of nematodes with tetracyclines affect Wolbachia and they get cleared from worm tissues; and this elimination causes reproductive abnormalities in worms and affect worm's embryogenesis, resulting in sterility. Although it is impractical, prolonged treatment with doxycycline significantly reduces the numbers of microfilaria in circulation, which is an important strategy to control transmission of filariasis by mosquito vectors. In this review, the current knowledge of Wolbachia as a drug target and potential ways to reduce the infection through anti-Wolbachia treatments is discussed.

High performance liquid chromatographic method for determination of doxycycline in human plasma and its application in pharmacokinetic studies

An accurate, sensitive and reproducible high performance liquid chromatographic [HPLC] method for the quantitation of doxycycline in plasma has been developed and validated. The drug and the internal standard were eluted from a micro-Bondapak C [18] column [3.9 mm x 150 mm, I.D., 5 micro m particle size] at room temperature with a mobile phase consisting of acetonitrile and water [28:72,% v/v]. The flow rate was 0.8 ml/min. A UV detector set at 346 nm was used to monitor the effluent. Each analysis required no longer than 6 min. Quantitation was achieved by measurement of the peak area ratio of the drug to the internal standard. The limit of detection was 10.0 ng/ml and the limit of quantification of doxycycline in plasma was 0.10 micro g/ml. The standard curve ranged from 0.1 to 2.5 micro g/ml. The intraday coefficient of variation [C.V.,%] ranged from 1.444 to 3.016%, and interday [C.V.,%] from 1.572 to 2.705% at four different concentrations. The relative recoveries ranged from 98.43 to 105.13% and the absolute recoveries ranged from 54.08 to 62.56% at four different concentrations. Stability studies showed that doxycycline is stable for at least 4 weeks in plasma after freezing at - 20 °C. The method was applied for the determination of the pharmacokinetic parameters of doxycycline after oral administration of 100 mg capsules of two commercially available formulations to 6 human volunteers

Spotlight on systemic antimicrobial adjunctive therapy in aggressive periodontitis

In this study, 35 adult patients with untreated aggressive periodontitis were exposed to a microbiological analysis to define the kind of oral microorganisms causing this disease. They were found to harbor sub-gingival Prevotella intermedia, Porphyromonas gingivalis, Capnocytophaga species, Actinobacillus actinomycetemcomitans and Eikenella corrodens as the common putative and anaerobic microorganisms causing the disease. Moreover, a follow up study was carried out on 45 adult patients with untreated aggressive periodontitis. According to the antimicrobial regimens, the patients were treated for 14 days with amoxicillin/clavulanic acid, either alone [group I] or combined with any of certain drugs, including doxycycline 100 mg/day [group II], metronidazole 750 mg/day [group III], doxycycline 100 mg/day and metronidazole 750 mg/day [group IV], doxycycline 20 mg twice daily and metronidazole 750 mg/day [group V]. The study concluded that the systemic administration of the antimicrobial agents as adjunctive therapy of aggressive periodontitis is effective in improving the inflammatory condition. Drug combination therapy is more effective than monotherapy with single agent. The administration of a combination of amoxicillin/clavulanic acid, metronidazole and doxycycline proved an optimum adjunctive drug therapy of periodontitis. The administration of doxycycline in this combination in a sub-antimicrobial dose of 20 mg bid is as effective as doxycycline in a dose of 100 mg/day

Polypeptides associated with in vitro cyst formation of Blastocystis hominis.

The objective of this study was to characterize the polypeptides associated with cysts of Blastocystis hominis. This form is believed to be infective and plays a role in parasite resistance to anti-B. hominis drugs currently used for treatment of Blastocystis associated diarrhea. Cysts were induced through in vitro culture of the parasite in complete medium supplemented with bacterial extract with trypticase, metronidazole or doxycycline. SDS-PAGE analysis showed almost similar polypeptide patterns of parasite extracts obtained from in vitro cultured parasites before and after exposure with the three supplements. Polypeptide bands at 76, 58.5, 48, 45, 40, 38, 32, 25 and 22 kDa were constantly seen in all antigenic preparations and no specific cyst-associated polypeptide was present. However, on immunoblot analysis, 3 out of 16 blastocystosis human sera identified a cyst-associated polypeptide at 60 kDa in all parasite extracts prepared from cultures with the three supplements. In addition, there were associated morphological changes detected in these parasites stained with acridine orange and observed under fluorescence microscopy. Metronidazole induced cyst forms (reddish cells) as early as 12 hours post-exposure; more cyst production (with stronger immunoblot bands) occurred after 24 hours exposure. However, cysts rupture with release and destruction of B. hominis daughters cells occurred after 48 hours exposure. Doxycycline induced less cyst-like forms at 24 hours (weaker 60 kDa band) and less destruction of the cysts (60 kDa band still present at 72 hours post exposure). Bacterial extract and trypticase also induced cysts at 12 hours with increasing numbers up to 72 hours exposure (corresponding increase in intensity of 60 kDa band from samples harvested at 12 to 72 hours post exposure) without any sign of deleterious effect on the parasite.

Actividad de las metaloproteinasas en el miocardio de ratas sometidas a endotoxina y su inhibición con doxiciclina / Metalloproteinase activity in myocardium of rats exposed to endotoxin: its inhibition with doxycycline

Background: The ventricular dysfunction of endotoxic shock could be secondary to the activity of myocardial metalloproteinases that degrade collagenous matrix. Metalloproteinase activity can be inhibited with doxycycline in some tissues. Aim: To study if the effect of endotoxemia on myocardial metalloproteinase activity can be inhibited with doxycycline. Material and methods: Left ventricular metalloproteinase activity was studied in four groups of rats. Group 1 received intraperitoneal dextrose in water, group 2 received 8 mg/kg intraperitoneal E coli endotoxin, group 3 received 60 mg/kg/day doxycycline for three days and group 4 received doxycycline and E coli endotoxin. Enzymatic activity was measured by Western Blot and zymography. Results: Zymography showed a higher metalloproteinase 2 (49 percent) and 9 (100 percent) activity in rats treated with endotoxin, when compared with control rats. In group 4, doxycycline reduced the activity of metalloproteinases 2 and 9 by 71 percent and 63 percent respectively, as compared with group 3. Western blot showed a 50 percent increase in the expression of metalloproteinase 1 in rats treated with endotoxin, that was reduced by 64 percent with the use of doxycycline. Conclusions: Endotoxin administration increases myocardial metalloproteinases and doxycyclin inhibits this activation. Therefore, doxycyclin could reduce the degradation of myocardial fibrillar collagen and ventricular dysfunction of endotoxic shock

Indirect inhibition by antibiotics of nucleotide and deoxynucleotide biosynthesis in Plasmodium falciparum.

The effects of the antibiotics, doxycycline, azithromycin, ciprofloxacin and chloramphenicol, upon levels of nucleoside-5'-triphosphates (NTPs) and 2'-deoxynucleoside-5'-triphosphates (dNTPs) have been compared in the malarial parasite, Plasmodium falciparum, and in human CCRF-CEM leukemia cells. All 4 antibiotics had more severe effects upon levels of NTPs and dNTPs in P. falciparum compared with leukemia cells providing an explanation for their selective toxicity against malaria and their utility as antimalarial drugs. In bacteria, the first 3 drugs inhibit protein synthesis while ciprofloxacin inhibits topoisomerase II. The observed depletions of NTPs and dNTPs would be a secondary effect of the drug but may result in death of the parasite.