Population Pharmacokinetics and Dose Evaluation of Cycloserine among Patients with Multidrug-Resistant Tuberculosis under Standardized Treatment Regimens.

Although cycloserine is a recommended drug for the treatment of multidrug-resistant tuberculosis (MDR-TB) according to World Health Organization (WHO), few studies have reported on pharmacokinetics (PK) and/or pharmacodynamics (PD) data of cycloserine in patients with standardized MDR-TB treatment. This study aimed to estimate the population PK parameters for cycloserine and to identify clinically relevant PK/PD thresholds, as well as to evaluate the current recommended dosage. Data from a large cohort with full PK curves was used to develop a population PK model. This model was used to estimate drug exposure in patients with MDR-TB from a multicentre prospective study in China. The classification and regression tree was used to identify the clinically relevant PK/PD thresholds. Probability of target attainment was analyzed to evaluate the currently recommended dosing strategy. Cycloserine was best described by a two-compartment disposition model. A percentage of time concentration above MICs (T>MIC) of 30% and a ratio of area under drug concentration-time curve (AUC0-24h) over MIC of 36 were the valid predictors for 6-month sputum culture conversion and final treatment outcome. Simulations showed that with WHO-recommended doses (500 mg and 750 mg for patients weighing <45 kg and ≥45 kg), the probability of target attainment exceeded 90% at MIC ≤16 mg/L in MGIT for both T>MIC of 30% and AUC0-24h/MIC of 36. New clinically relevant PK/PD thresholds for cycloserine were identified in patients with standardized MDR-TB treatment. WHO-recommended doses were considered adequate for the MGIT MIC distribution in our cohort of Chinese patients with MDR-TB.

A zebrafish drug screening platform boosts the discovery of novel therapeutics for spinal cord injury in mammals.

Spinal cord injury (SCI) is a complex condition, with limited therapeutic options, that results in sensory and motor disabilities. To boost discovery of novel therapeutics, we designed a simple and efficient drug screening platform. This innovative approach allows to determine locomotor rescue properties of small molecules in a zebrafish (Danio rerio) larval spinal cord transection model. We validated our screening platform by showing that Riluzole and Minocycline, two molecules that are in clinical trials for SCI, promote rescue of the locomotor function of the transected larvae. Further validation of the platform was obtained through the blind identification of D-Cycloserine, a molecule scheduled to enter phase IV clinical trials for SCI. Importantly, we identified Tranexamic acid and further showed that this molecule maintains its locomotor recovery properties in a rodent female contusion model. Our screening platform, combined with drug repurposing, promises to propel the rapid translation of novel therapeutics to improve SCI recovery in humans.

Initial experience of bedaquiline implementation under the National TB Programme at NITRD, Delhi, India.

BACKGROUND: Bedaquiline (BDQ) was approved for treatment of drug resistant TB (DR-TB) under Conditional Access Programme (CAP) of Revised National Tuberculosis Control Programme (RNTCP) and was also implemented in the National Institute of TB and Respiratory Diseases (NITRD). We present early efficacy and safety of BDQ containing regimens for DR-TB. OBJECTIVE: To ascertain the early efficacy and safety of Bedaquline containing regimens in treatment of DR-TB. METHODS: BDQ containing regimens along with other drugs were designed as per WHO recommendations for DR-TB patients. They were followed up for sputum smear and culture conversion, adverse events during the treatment. RESULTS: A cohort of 290 DR-TB patients (Median age-29.77) were initiated on BDQ containing regimens. Of the available Sputum results, smear conversion was seen in 51% and 91% patients at the end of 1st week and 3rd month respectively. Similarly, 93% and 98% patients had culture conversion at the end of 3rd and 6th month respectively. 201 adverse events (AE) including 47 deaths were reported among 109 patients. QTc prolongation was seen in 29% patients but only 4 required discontinuation of BDQ. Lost to follow up of treatment was about 6%. CONCLUSION: Bedaquiline along with an optimized background regimen has shown early sputum conversion in larger number of difficult to treat patients having additional resistance of second line drugs along with INH and Rifampicin. The regimen is feasible in programmatic conditions and is relatively safe.

Tratamento clínico de zumbido primário em adultos e idosos: revisão sistemática / Clinical treatment of primary tinnitus in adults and in the elderly: systematic review

O zumbido no ouvido é definido como uma ilusão auditiva ou sensação sonora endógena, não relacionada a nenhuma fonte externa de estimulação. É um sintoma frequente na população idosa. Até hoje, vários autores argumentam que o desconhecimento da etiologia do zumbido, aliado à subjetividade desta manifestação, mais a sobreposição das enfermidades e dos sintomas que, geralmente, acometem os pacientes idosos, dificultam a obtenção de um bom resultado terapêutico. O objetivo desta revisão foi levantar quais os tratamentos clínicos mais utilizados na prática clínica no tratamento do zumbido primário em adultos e idosos. Procedeu-se à verificação do status dos últimos 5 anos de estudos em textos de acesso livre, no banco de dados eletrônicos da PubMed. Apresentaram tratamentos clínicos para o zumbido primário 25 artigos; aqueles com resultados satisfatórios foram quatro artigos sobre acupuntura, dois sobre neuromodulação de resenha coordenada acústica, um sobre uso combinado de amplificação e gerador de som, e um sobre psicoterapia corporal, que incluíam tanto adultos e idosos, tendo a idade média entre 51 a 54 anos. Não se pode afirmar que os tratamentos propostos são eficazes na cura dos sintomas de zumbido em adultos e idosos, mas sim que existem algumas terapêuticas de baixo custo que apresentam respostas relativamente satisfatórias. (AU)

Tinnitus is defined as a hearing illusion or endogenous auditory sensation that is not related to any external stimulation source. It is a frequent symptom among elderly people. To date, many authors have argued that the lack of knowledge about the tinnitus etiology, added to the subjectivity of this manifestation, and the overlap of other diseases and symptoms that often occur with aged patients make the obtainment of a good therapeutic result difficult. The objective of this review was to find the most used clinical treatment in clinical practice for primary tinnitus on adults and elderly. The status of the last five years of studies in free full texts on PubMed database was checked. Twenty-five articles showed clinical treatment for primary tinnitus, with four articles about acupuncture, two about acoustic coordinate reset neuromodulation, one about sound generator associated with conventional amplification, and one about body-psychotherapy which included adults and elderly with an average age between 51 to 54 years old showing satisfactory results. It is difficult to state that the proposed treatment is efficient on healing the tinnitus symptoms on adults and elderly but there are some low-cost therapies showing relatively satisfactory responses. (AU)

Validation of Cycloserine Efficacy in Treatment of Multidrug-Resistant and Extensively Drug-Resistant Tuberculosis in Beijing, China.

Cycloserine (Cs) is recommended by the World Health Organization as a second-line drug to treat multidrug-resistant tuberculosis (MDR-TB); however, its efficacy has never been sufficiently evaluated. To gain some insights into the value of cycloserine for MDR-TB treatment, in vitro bacteriostatic effect was determined and patient validations were performed prospectively. The in vitro activity of Cs against 104 wild-type Mycobacterium tuberculosis strains was determined, and serum Cs concentrations were measured for 73 MDR TB patients 2 h after administration. The treatment outcomes for 27 MDR-TB patients who had baseline isolates and were treated with Cs-containing regimens were followed up. The MICs for 90% of the recruited 104 wild-type strains were below 32 µg/ml. Eighteen out of 52 patients had peak serum concentrations (Cmax) below 20 µg/ml at the dosage of 500 mg daily, while 13 out of 21 patients had peak serum concentrations higher than 35 µg/ml at the dosage of 750 mg daily. The percentage of favorable treatment outcomes among patients with a Cmax/MIC ratio of ≥1 was statistically significantly higher than that among the group with a Cmax/MIC ratio of <1 (P = 0.022). The epidemiological cutoff value for Cs susceptibility testing was 32 µg/ml. A high percentage of patients receiving the recommended dosage of 10 mg/kg for Cs administration could not acquire desirable blood concentrations; therefore, adjusting the dosage according to drug concentration monitoring is necessary. The Cmax/MIC ratio might be a good indicator for predicting the treatment outcome for patients with MDR-TB or extensively drug-resistant TB (XDR-TB) who are being administered Cs-containing regimens.

d-Cycloserine augmentation of cognitive remediation in schizophrenia.

d-Cycloserine (DCS) has been shown to enhance memory and, in a previous trial, once-weekly DCS improved negative symptoms in schizophrenia subjects. We hypothesized that DCS combined with a cognitive remediation (CR) program would improve memory of a practiced auditory discrimination task and that gains would generalize to performance on unpracticed cognitive tasks. Stable, medicated adult schizophrenia outpatients participated in the Brain Fitness CR program 3-5 times per week for 8weeks. Subjects were randomly assigned to once-weekly adjunctive treatment with DCS (50mg) or placebo administered before the first session each week. Primary outcomes were performance on an auditory discrimination task, the MATRICS cognitive battery composite score and the Scale for the Assessment of Negative Symptoms (SANS) total score. 36 subjects received study drug and 32 completed the trial (average number of CR sessions=26.1). Performance on the practiced auditory discrimination task significantly improved in the DCS group compared to the placebo group. DCS was also associated with significantly greater negative symptom improvement for subjects symptomatic at baseline (SANS score ≥20). However, improvement on the MATRICS battery was observed only in the placebo group. Considered with previous results, these findings suggest that DCS augments CR and alleviates negative symptoms in schizophrenia patients. However, further work is needed to evaluate whether CR gains achieved with DCS can generalize to other unpracticed cognitive tasks.

Plasma drug activity in patients on treatment for multidrug-resistant tuberculosis.

Little is known about plasma drug concentrations relative to quantitative susceptibility in patients with multidrug-resistant tuberculosis (MDR-TB). We previously described a TB drug activity (TDA) assay that determines the ratio of the time to detection of plasma-cocultured Mycobacterium tuberculosis versus control growth in a Bactec MGIT system. Here, we assess the activity of individual drugs in a typical MDR-TB regimen using the TDA assay. We also examined the relationship of the TDA to the drug concentration at 2 h (C2) and the MICs among adults on a MDR-TB regimen in Tanzania. These parameters were also compared to the treatment outcome of sputum culture conversion. Individually, moxifloxacin yielded superior TDA results versus ofloxacin, and only moxifloxacin and amikacin yielded TDAs equivalent to a -2-log killing. In the 25 patients enrolled on a regimen of kanamycin, levofloxacin, ethionamide, pyrazinamide, and cycloserine, the C2 values were found to be below the expected range for levofloxacin in 13 (52%) and kanamycin in 10 (40%). Three subjects with the lowest TDA result (<1.5, a finding indicative of poor killing) had significantly lower kanamycin C2/MIC ratios than subjects with a TDA of ≥1.5 (9.8 ± 8.7 versus 27.0 ± 19.1; P = 0.04). The mean TDAs were 2.52 ± 0.76 in subjects converting to negative in ≤2 months and 1.88 ± 0.57 in subjects converting to negative in >2 months (P = 0.08). In Tanzania, MDR-TB drug concentrations were frequently low, and a wide concentration/MIC range was observed that affected plasma drug activity ex vivo. An opportunity exists for pharmacokinetic optimization in current MDR-TB regimens, which may improve treatment response.

Augmenting transcranial direct current stimulation with (D)-cycloserine for depression: a pilot study.

OBJECTIVES: Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that causes changes in cortical excitability. Recent double-blind placebo-controlled clinical trials suggest that tDCS may be efficacious in the treatment of depression. Pharmacological agents that prolong the effects of tDCS could lead to greater cumulative changes in cortical excitability, producing greater and more prolonged efficacy. One agent shown to prolong the excitability-enhancing effects of tDCS in healthy subjects is D-Cycloserine, a partial agonist at the glycine-binding site of N-methyl-D-aspartate receptors. We investigated whether combining prefrontal tDCS with D-Cycloserine could enhance and/or prolong the antidepressant effect of tDCS. METHODS: Five depressed subjects who had relapsed or failed to achieve remission after receiving a previous course of prefrontal tDCS were recruited. In this open-label pilot study, subjects ingested 100-mg D-Cycloserine 2 hours before tDCS sessions. Subjects received 20 minutes of tDCS at 2 mA on consecutive weekdays for a total of 20 sessions. The anode was placed at pF3 and the cathode at F8 (10/20 system). Clinical response was assessed using the Montgomery-Åsberg Depression Rating Scale (MADRS). RESULTS: The change in Montgomery-Åsberg Depression Rating Scale scores was not greater with the combination of D-Cycloserine and tDCS than had previously been produced by tDCS alone. No significant additional adverse effects were reported. CONCLUSIONS: This pilot open-label study found that pretreatment with 100-mg D-Cycloserine 2 hours before tDCS was well tolerated but did not enhance the antidepressant efficacy of anodal prefrontal tDCS.

Extensively drug-resistant tuberculosis: New Zealand's first case and the challenges of management in a low-prevalence country.

In 2010, an immigrant from Burma was the first person to be diagnosed in New Zealand with extensively drug-resistant tuberculosis (XDR-TB). The strain of Mycobacterium tuberculosis is the most resistant reported to date in Australasia. Key difficulties of managing this disease in a low-prevalence country were delays from drug-susceptibility testing and in acquiring appropriate medicines, and a lack of evidence-based guidelines. Solutions are needed for New Zealand and the wider region as more cases of XDR-TB are likely to be encountered in the future.

Impact of extensively drug-resistant tuberculosis on treatment outcome of multidrug-resistant tuberculosis patients with standardized regimen: report from Iran.

The limited experience in treating patients with extensively drug-resistant tuberculosis (XDR-TB) shows a therapeutic success rate under 50-60% and there are no publications regarding the outcome of these patients treated with standardized regimens. All multidrug-resistant tuberculosis (MDR-TB) patients hospitalized at the Masih Daneshvari Hospital in Tehran, Iran, during 2004-2007 were recruited. Drug susceptibility testing to 14 drugs (including eight second-line drugs) was performed and a standardized regimen with ofloxacin, cycloserine, prothionamide, and amikacin was administered for all patients. Outcome of the patients was studied, comparing between the MDR-TB non-XDR-TB and the XDR-TB. Fifty-one patients were included, 12 with XDR-TB criteria. Of 51, 48 were HIV negative and HIV status was unknown in three cases. All 12 were HIV negative. XDR-TB infection was significantly associated only with age (p = 0.039). The success rates for the total 51 MDR-TB, the 39 MDR-TB non-XDR-TB, and the 12 XDR-TB patients were 76.5% (39 patients), 87.2% (34 patients), and 41.7% (5 patients), respectively. Resistance to ofloxacin, ciprofloxacin, and amikacin were found to be significantly associated with unsuccessful outcome. In this setting, a standardized second-line drugs regimen produces high treatment success rates in MDR-TB patients unless XDR-TB is present.

Pharmacological enhancement of behavioral therapy: focus on posttraumatic stress disorder.

Improved efficacy in the treatment of posttraumatic stress disorder (PTSD) and other anxiety disorders is urgently needed. Traditional anxiety treatments of hypnosis and psychodynamic therapy may be of some help, but uncontrolled studies lead to inconclusive results on the efficacy of these treatment techniques. There is a larger literature supporting the efficacy of cognitive-behavioral procedures with PTSD, including prolonged exposure therapy, eye movement desensitization and reprocessing, and anxiety management techniques. The cutting-edge technology of virtual reality-based exposure therapy for PTSD is particularly exciting. To further build on effective psychosocial treatments, current pharmacological augmentation approaches to emotional learning are being combined with psychotherapy. In particular, D-cycloserine, a partial NMDA agonist, has shown to be effective in facilitating the exposure/extinction therapy to improve the efficacy of treating anxiety disorders, and may guide the way for new pharmacological enhancements of behavioral therapy.

Terapia cognitivo-comportamental no transtorno de pânico / Cognitive-behavioral therapy in panic disorder

OBJETIVO: O transtorno de pânico é uma condição crônica e recorrente que prejudica a qualidade de vida e o funcionamento psicossocial dos portadores. Embora os medicamentos sejam efetivos na redução dos ataques de pânico, muitos pacientes não respondem adequadamente a essas intervenções. A terapia cognitivo-comportamental fornece um método alternativo eficaz para tratar transtorno de pânico e evitação agorafóbica. O objetivo do estudo é o de descrever o uso de técnicas cognitivo-comportamentais no tratamento do transtorno de pânico. MÉTODO: Revisão narrativa a partir dos bancos de dados do Medline, SciELO e PsycInfo e de livros-texto especializados. RESULTADOS: Foram descritos os fundamentos da terapia cognitivo-comportamental no tratamento do transtorno pânico e revisadas as evidências de eficácia em curto e longo prazos. O uso de medicação concomitante a terapia cognitivo-comportamental foi também discutido. CONCLUSÕES: A terapia cognitivo-comportamental individual ou em grupo é eficaz para pacientes com transtorno de pânico, seja como tratamento de primeira linha ou como um próximo passo para pacientes com resposta parcial a outros tratamentos.

OBJECTIVE: Panic disorder is a chronic and recurrent condition that impairs an individual's psychosocial functioning and quality of life. Despite the efficacy of psychopharmacological treatment in reducing panic attacks, many patients fail to respond adequately to these interventions. Cognitive behavioral therapy provides an alternative and efficacious method for treating panic disorder and agoraphobic avoidance. The objective of the study is to describe the use of cognitive behavioral therapy for panic disorder. METHOD: Narrative review of data collected from Medline, SciELO and PsycInfo and specialized textbooks. RESULTS: We describe the cognitive-behavioral model for the treatment of panic disorder, and review both short and long-term efficacy findings. We also discuss the role of combined treatment (cognitive behavioral therapy and psychopharmacology). CONCLUSIONS: Cognitive behavioral therapy, either individual or in group, can be used as first-line therapy for panic disorder. This treatment modality can also be indicated as a next step for patients failing to respond to other treatments.

Exposición a tuberculosis multirresistente: estudio y seguimiento de nueve niños / Exposure to multiresisant tuberculosis: study and follow-up of nine children

Durante los últimos años se ha observado un incremento mundial de la tuberculosis multirresistente (TB-MDR). En España con el aumento de la inmigración desde países con endemia elevada de tuberculosis, estamos asistiendo a un mayor número de diagnósticos. En niños las series publicadas al respecto son escasas y no existen directrices claras de tratamiento de la enfermedad, de la infección tuberculosa latente y de la profilaxis tras exposición a enfermo bacilífero TB-MDR. Se presenta la actitud inicial y la evolución de nueve niños con exposición a un caso índice: mujer ecuatoriana diagnosticada de tuberculosis bacilífera resistente a isoniacida, rifampicina y pirazinamida (AU)

A world increase in multidrug-resistant tuberculosis (MDR-TB) has been reported over the last few years. A larger number of diagnoses are being seen in Spain, due to the increase of immigration from high endemic TB countries. Articles published on this are anecdotal in children, and there is no clear directives for treatment of MDR-TB, or latent tuberculosis infection (ITBL) or on prophylaxis after exposure to active pulmonary MDR-TB. We present the initial management and progression of nine children after close contact exposure to an Ecuadorian woman diagnosed with active pulmonary TB, resistant to Isoniazid, Rifampicin and Pyrazinamide (AU)

Outcome of multi-drug resistant tuberculosis cases treated by individualized regimens at a tertiary level clinic.

AIM: To determine the clinical, radiological and drug resistance profile as well as the factors associated with treatment outcome of Multi-Drug Resistant Tuberculosis (MDR-TB). MATERIAL AND METHODS: All newly diagnosed patients with pulmonary MDR-TB from August 2002 to December 2004 enrolled at New Delhi Tuberculosis Centre, were included in the study. They were followed up clinically, radiologically and bacteriologically by sputum smear, culture and Drug Susceptibility Testing (DST) at regular intervals. According to their DST pattern and previous history of Anti-Tubercular Treatment (ATT), individualized treatment regimens were tailored for each patient. RESULTS: Out of total 27 bacteriologically proven cases of MDR-TB included in this study, 19 were males (mean age and weight 38.5 years and 52.6 kgs, respectively) and eight females (mean age and weight 34.3 years and 40.7 kgs, respectively). A majority (18) were residents of Delhi and the rest hailed from different parts of North India. All of them had a history of previous treatment ranging from six to 34 months. Cavity on chest X-rays was seen in 81%, while 44% showed extensive involvement. The patients received at least four "second line drugs" during their treatment with a mean of 6.2 anti-tubercular drugs during their intensive phase. Of the 27 patients, 13 were cured, 10 defaulted, one died, one is still on treatment and two were referred for surgery. Radiological improvement was observed in two third of cases and chest X-ray of two patients showed a complete resolution. Six predictors were identified for successful outcome of MDR-TB. They include weight gain at six months, culture conversion, radiological improvement during treatment, disease with M. tuberculosis strains exhibiting resistance to less than or up to three anti-tubercular drugs, use of less than or up to three second line drugs in treatment and no change of regimen during treatment. CONCLUSION: Default from treatment was observed to be a major challenge in the treatment of MDR-TB due to long duration and expense of ATT.

Absence of significant interactive effects of high-dose D-cycloserine and ethanol in healthy human subjects: preliminary insights into ethanol actions at the glycine B site of NMDA glutamate receptors.

BACKGROUND: Ethanol reduces N-methyl-d-aspartate (NMDA) glutamate receptor function via multiple cellular targets. It is not yet clear whether direct ethanol antagonism of the glycine(B) co-agonist site of NMDA receptors is relevant to this effect. The purpose of this study was to evaluate whether ethanol effects at the glycine(B) co-agonist site was clinically relevant by evaluating some aspects of the psychopharmacologic interactions between the glycine(B) partial agonist, D-cycloserine (DCS), and ethanol in healthy human subjects. METHODS: All subjects completed 4 test days under double-blind conditions in which DCS or placebo was administered orally prior to ethanol or an ethanol-tainted placebo drink. Two groups of healthy subjects were studied. A first group of subjects (n = 25) were pretreated orally with DCS 500 mg or placebo 4 hours prior to ethanol (0.8 g/kg, p.o. or placebo) administration. A second group of subjects (n = 20) were pretreated with DCS 1000 mg or placebo prior to ethanol administration. Outcomes included subjective and cognitive responses to the experimental interventions. RESULTS: Predictable ethanol responses were observed in both groups of subjects, although the response to ethanol and the breath alcohol levels, but not plasma alcohol levels, were slightly but significantly lower in the group that received the higher DCS dose. DCS produced mild sedative effects that were greater for the lower than the higher dose. It also produced a mild impairment of verbal fluency without impairing attention. No statistically significant interactions between ethanol and DCS emerged in analyses. However, the combination of ethanol and DCS produced significantly greater impairment than both ethanol or DCS administered alone on a test of verbal fluency and aspects of memory function. IMPLICATIONS: DCS and ethanol both produced sedative and cognitive effects, consistent with their ability to reduce NMDA receptor function. However, the absence of interactive effects observed in this study raises questions about the clinical significance of the glycine(B) site as a target for ethanol in the brain at levels of ethanol intoxication associated with social drinking. However, it should be noted that this conclusion is limited to the dependent measures evaluated and the doses of ethanol and DCS studied.

Selective increase in the extracellular D-serine contents by D-cycloserine in the rat medial frontal cortex.

A partial agonist of the N-methyl-D-aspartate (NMDA) receptor, D-cycloserine, acting at its glycine modulatory site, ameliorates the neuropsychiatric symptoms that are mimicked by NMDA antagonists and include cognitive disturbances, antipsychotic-resistant schizophrenic symptoms and cerebellar ataxia. To obtain a further insight into the mechanisms of the therapeutic efficacies of D-cycloserine, we investigated the effects of the systemic administration of D-cycloserine on the extracellular contents of an endogenous NMDA co-agonist, D-serine, in the medial frontal cortex of the rat using an in vivo dialysis technique. An acute intraperitoneal injection of D-cycloserine (50 and 100 mg/kg) caused an increase in extracellular concentrations of D-serine without significant effects on those of L-serine, glycine, L-glutamate, L-aspartate, L-glutamine, L-asparagine, L-alanine, L-threonine and taurine in the medial frontal cortex. The selective increase in the extracellular D-serine contents may, at least partially, be associated with the facilitating effects of D-cycloserine on the NMDA receptor functions in addition to its direct stimulation of the NMDA receptor glycine site.

Susceptibility tests to second line drugs and re-treatment of tuberculosis revisiting early experiences.

The value of susceptibility tests in guiding antituberculous therapy with second-line drugs remains controversial. We reanalyzed three reports regarding the relationship between in vitro susceptibility of Mycobacterium tuberculosis and the clinical outcome of in-patients treated with these drugs at the Muñiz Hospital, Buenos Aires, during the sixties. These patients had been irregularly treated with a standard regimen consisting of isoniazid, streptomycin and PAS; they developed resistance to at least the first two drugs and persisted culture-positive. Susceptibility testing to ethionamide, cycloserine and kanamycin were performed by the proportion method on Löwenstein Jensen medium. Some level of resistance was detected among isolates from patients not previously treated with these drugs, that could be due to cross resistance with previously administered first line structural analogs. However, the studies evidenced significant association between resistance to ethionamide and cycloserine and prior treatment with these drugs. Increased resistance to all three drugs was detected within the first three months of treatment. In vitro resistance to ethionamide emerged earlier and was the most frequent followed by resistance to cycloserine and kanamycin. The low frequency of resistance to kanamycin could be related to the low dosage of this drug used at that time. Simultaneous resistance to the three agents, but not to two or one drug, appeared to be a marker of treatment failure. An apparent reversion of drug resistance was observed in near 6% of patients, for whom susceptibility tests were repeated on subsequent isolates, indicating this percentage of inconsistency in reproducibility of test results.

D-cycloserine improves functional recovery and reinstates long-term potentiation (LTP) in a mouse model of closed head injury.

Traumatic brain injury triggers a massive glutamate efflux, activation of NMDA receptor channels, and cell death. Recently, we reported that NMDA receptors in mice are down-regulated from hours to days following closed head injury (CHI), and treatment with NMDA improved recovery of motor and cognitive functions up to 14 d post-injury. Here we show that a single injection of a low dose of D-cycloserine (DCS), a partial NMDA receptor agonist, in CHI mice 24 h post-injury, resulted in a faster and greater recovery of motor and memory functions as assessed by neurological severity score and object recognition tests, respectively. Moreover, DCS treatment of CHI mice led to a significant improvement of hippocampal long-term potentiation (LTP) in the CA1 region that was completely blunted in CHI control mice. However, DCS did not improve CHI-induced impairment in synaptic glutamate release measured by paired pulse facilitation (PPF) ratio in hippocampal CA1 region. Finally, CHI-induced reduction of brain-derived neurotrophic factor (BDNF) was fully restored following DCS treatment. Since DCS is in clinical use for other indications, the present study offers a novel approach to treat human brain injury.

Susceptibility tests to second line drugs and re-treatment of tuberculosis: revisiting early experiences / Las pruebas de sensibilidad a drogas de segunda línea y el re-tratamiento de la tuberculosis: visión retrospectiva de tres estudios

The value of susceptibility tests in guiding antituberculous therapy with second-line drugs remains controversial. We reanalyzed three reports regarding the relationship between in vitro susceptibility of Mycobacterium tuberculosis and the clinical outcome of in-patients treated with these drugs at the Muñiz Hospital, Buenos Aires, during the sixties. These patients had been irregularly treated with a standard regimen consisting of isoniazid, streptomycin and PAS; they developed resistance to at least the first two drugs and persisted culture-positive. Susceptibility testing to ethionamide, cycloserine and kanamycin were performed by the proportion method on Löwenstein Jensen medium. Some level of resistance was detected among isolates from patients not previously treated with these drugs, that could be due to cross resistance with previously administered first line structural analogs. However, the studies evidenced significant association between resistance to ethionamide and cycloserine and prior treatment with these drugs. Increased resistance to all three drugs was detected within the first three months of treatment. In vitro resistance to ethionamide emerged earlier and was the most frequent followed by resistance to cycloserine and kanamycin. The low frequency of resistance to kanamycin could be related to the low dosage of this drug used at that time. Simultaneous resistance to the three agents, but not to two or one drug, appeared to be a marker of treatment failure. An apparent reversion of drug resistance was observed in near 6% of patients, for whom susceptibility tests were repeated on subsequent isolates, indicating this percentage of inconsistency in reproducibility of test results.

La correlación entre resultados de pruebas de sensibilidad a drogas antituberculosas de segunda línea y evolución de los pacientes en tratamiento, aún es discutida. Se reanalizan aquí tres estudios realizados en la década del 60, sobre la relación entre resultados de pruebas de sensibilidad y tratamiento con estas drogas, en pacientes crónicos, internados en el hospital Muñiz, Buenos Aires, que habían sido tratados con el entonces régimen estándar, integrado por isoniacida, estreptomicina y PAS; se habían hecho resistentes al menos a dos de estas drogas y continuaban con cultivo positivo. La prueba de sensibilidad a etionamida, cicloserina y kanamicina se efectuó por el método de las proporciones en medio Löwenstein Jensen. Entre 4 y 13% de los pacientes previamente no tratados con estas drogas presentó cierto nivel de resistencia, fenómeno atribuido a la administración previa de drogas de primera línea con moléculas análogas. Se halló asociación significativa entre resistencia a etionamida y cicloserina, y tratamiento previo con estas drogas. La resistencia a las tres drogas fue detectada en los primeros tres meses de tratamiento, siendo la resistencia a etionamida la más frecuente, y la primera en emerger, seguida por cicloserina y kanamicina, cuya baja frecuencia en alcanzar resistencia estaría relacionada con las bajas dosis administradas. La resistencia simultánea a las tres drogas, pero no a una o dos, resultó marcadora de fracaso terapéutico. Se observó en cerca del 6% de los pacientes aparente reversión de la resistencia, en pruebas hechas en aislamientos sucesivos, interpretada como falla en la reproducibilidad de resultados.

Susceptibility tests to second line drugs and re-treatment of tuberculosis: revisiting early experiences / Las pruebas de sensibilidad a drogas de segunda línea y el re-tratamiento de la tuberculosis: visión retrospectiva de tres estudios

The value of susceptibility tests in guiding antituberculous therapy with second-line drugs remains controversial. We reanalyzed three reports regarding the relationship between in vitro susceptibility of Mycobacterium tuberculosis and the clinical outcome of in-patients treated with these drugs at the Muñiz Hospital, Buenos Aires, during the sixties. These patients had been irregularly treated with a standard regimen consisting of isoniazid, streptomycin and PAS; they developed resistance to at least the first two drugs and persisted culture-positive. Susceptibility testing to ethionamide, cycloserine and kanamycin were performed by the proportion method on L÷wenstein Jensen medium. Some level of resistance was detected among isolates from patients not previously treated with these drugs, that could be due to cross resistance with previously administered first line structural analogs. However, the studies evidenced significant association between resistance to ethionamide and cycloserine and prior treatment with these drugs. Increased resistance to all three drugs was detected within the first three months of treatment. In vitro resistance to ethionamide emerged earlier and was the most frequent followed by resistance to cycloserine and kanamycin. The low frequency of resistance to kanamycin could be related to the low dosage of this drug used at that time. Simultaneous resistance to the three agents, but not to two or one drug, appeared to be a marker of treatment failure. An apparent reversion of drug resistance was observed in near 6% of patients, for whom susceptibility tests were repeated on subsequent isolates, indicating this percentage of inconsistency in reproducibility of test results.(AU)

La correlación entre resultados de pruebas de sensibilidad a drogas antituberculosas de segunda línea y evolución de los pacientes en tratamiento, aún es discutida. Se reanalizan aquí tres estudios realizados en la década del 60, sobre la relación entre resultados de pruebas de sensibilidad y tratamiento con estas drogas, en pacientes crónicos, internados en el hospital Muñiz, Buenos Aires, que habían sido tratados con el entonces régimen estándar, integrado por isoniacida, estreptomicina y PAS; se habían hecho resistentes al menos a dos de estas drogas y continuaban con cultivo positivo. La prueba de sensibilidad a etionamida, cicloserina y kanamicina se efectuó por el método de las proporciones en medio L÷wenstein Jensen. Entre 4 y 13% de los pacientes previamente no tratados con estas drogas presentó cierto nivel de resistencia, fenómeno atribuido a la administración previa de drogas de primera línea con moléculas análogas. Se halló asociación significativa entre resistencia a etionamida y cicloserina, y tratamiento previo con estas drogas. La resistencia a las tres drogas fue detectada en los primeros tres meses de tratamiento, siendo la resistencia a etionamida la más frecuente, y la primera en emerger, seguida por cicloserina y kanamicina, cuya baja frecuencia en alcanzar resistencia estaría relacionada con las bajas dosis administradas. La resistencia simultánea a las tres drogas, pero no a una o dos, resultó marcadora de fracaso terapéutico. Se observó en cerca del 6% de los pacientes aparente reversión de la resistencia, en pruebas hechas en aislamientos sucesivos, interpretada como falla en la reproducibilidad de resultados.(AU)