Antimicrobial activities of novel bipyridine compounds produced by a new strain of Saccharothrix isolated from Saharan soil

The actinobacterium strain ABH26 closely related to Saccharothrix xinjiangensis, isolated from an Algerian Saharan soil sample, exhibited highly antagonist activity against Gram-positive bacteria, yeasts and filamentous fungi. Its ability to produce antimicrobial compounds was investigated using several solid culture media. The highest antimicrobial activity was obtained on Bennett medium. The antibiotics secreted by strain ABH26 on Bennett medium were extracted by methanol and purified by reverse-phase HPLC using a C18 column. The chemical structures of the compounds were determined after spectroscopic (¹H NMR, ¹³C NMR, ¹H-¹H COSY and ¹H-¹³C HMBC spectra), and spectrometric (mass spectrum) analyses. Two new cyanogriside antibiotics named cyanogriside I (1) and cyanogriside J (2), were characterized along with three known caerulomycins, caerulomycin A (3), caerulomycin F (4) and caerulomycinonitrile (5). This is the first report of cyanogrisides and caerulomycins production by a member of the Saccharothrix genus. The minimum inhibitory concentrations (MIC) of these antibiotics were determined against pathogenic microorganisms.     

小儿智商、出生体重与成孕日父母生物节律关系的初步探讨

对107名小儿调查分析其智商及出生体重与成孕日父母生物节律的相关性，获得了有意义的结论：①小儿智商与成孕时父母的智力节律处于高潮期有关，②小儿出生体重与成孕时父母的体力节律处于高潮期有关。本组资料为我们倡导的“先咨询、后受孕”提供了依据，指出选择高潮期妊娠配合孕期保健有助于优生。     

Respiratory frequencies of sleeping infants during the first months of life: Correlations between values in different sleep states

This study was carried out on 57 normal infants: 22 full-term newborns, examined in the hospital laboratory, and 35 2–18-wk-old infants, examined in two resident nurseries. Polygraphic records, including 1–3 complete sleep cycles, were performed during the morning. The tracings were analyzed by 20-sec epochs.Three to 10% of active sleep states (AS) and 0.8-4% of quiet sleep states (QS) included ?3 sec respiratory pauses. There were minimal, non-significant differences between respiratory frequencies (RF) in total and in no-pause tracings.Our results confirmed that RF was higher in AS in all ages, when compared with QS (P < 0.02). During the transition (TS) from one to another well-defined sleep state, the respiratory rate showed an intermediate level (AS > TS > QS): the transition from AS to QS showed progressive slowing of RF, while the transition from QS to AS occurred abruptly, with sudden acceleration of RF. There was a significant slowing of RF during the course of QS, while the RF in AS was more variable without significant differences between the beginning, the middle and the end of AS state. In this material, RF was higher in 2–5-wk and 6–10-wk age groups, compared to newborns and to 11-18-wk-old infants. At all ages, there was a high degree of correlation (P < 0.01) between RF found in different sleep states for given individuals: some infants breathed more rapidly and others more slowly in all sleep states.A review of the literature showed that the differences between normal RF     

The molecular biology of distraction osteogenesis

Distraction osteogenesis has become a mainstay in bone engineering and the recent application of this technique to the membranous craniofacial skeleton has significantly improved our armamentarium for reconstructive craniomaxillofacial procedures. However, if the biomechanical, histological and ultrastructural changes associated with distraction osteogenesis have been widely described, the molecular mechanisms governing the formation of new bone in the interfragmental gap of gradually distracted bone segments remain largely unclear. Recently, our laboratory has described a rat mandibular distraction model that provides an excellent environment for deciphering the molecular mechanisms that mediate distraction osteogenesis. In this Article, we present the hypotheses and current research that have furthered our knowledge of the molecular mechanisms that govern distraction osteogenesis. Recent studies have implicated a growing number of cytokines that are intimately involved in the regulation of bone synthesis and turnover. The gene regulation of numerous cytokines (Transforming Growth Factor-B, Bone Morphogenetic Proteins, Insulin-like Growth Factor-1, Fibroblast Growth Factor-2) during distraction osteogenesis have been best characterized and will be discussed in this text. We believe that novel systems like the rat model will facilitate our understanding of the biomolecular mechanisms that mediate membranous distraction osteogenesis and will ultimately guide the development of targeted-strategies designed to accelerate bone healing.     

Performances of the Amplified Mycobacterium Tuberculosis Direct Test in non respiratory specimens (study about 1538 samples)

From March 1998 to August 2009, 1538 non-respiratory samples collected from 1182 patients, were tested using the Gen-Probe Amplified Mycobacterium Direct Test™ (AMTD). After decontamination procedure, every sample was tested by AMTD and by culture on solid and liquid media. The “Gold-standard” was considered by the combination of culture results and clinical diagnosis. Tuberculosis was present in 17,59 % (208 patients). For theses 1538 non-respiratory samples (225 culture positive samples, 248 AMTD positive), 279 corresponded to tuberculosis. After resolving the discordant results, the sensitivity, specificity, positive and negative values were 89, 99, 99,6 and 97,3 %.     

Radiation sensitivity of Bloom's syndrome lymphocytes during S and G2 phases

In order to study chromosome sensitivity of Bloom's syndrome (BS) cells in relation to the replication stage, gamma-ray irradiation was performed immediately before adding bromodeoxyuridine (BrdU) to lymphocyte cultures of one BS patient and of one control. It was found that BS cells are much more sensitive to the irradiation than control cells at the end of S and at G2 phases. The rate of induction of chromosome breaks is significantly increased and that of chromatid breaks and exchanges is also increased, though to a lesser degree. Our results also favor the existence of a cell subpopulation in BS characterized by a slow cycle, a high spontaneous chromosome aberration rate, and a high radiation sensitivity.     

Relationship between lipogenesis,ketogenesis, and malonyl-CoA content in isolated hepatocytes from the obese Zucker rat adapted to a high-fat diet

The relationship between lipogenesis and ketogenesis and the concentration of malonyl coenzyme A (CoA) was investigated in hepatocytes from adult obese Zucker rats and their lean littermates fed either a control low-fat diet or a high-fat diet (30% lard in weight). With the control diet, lipogenesis—although strongly inhibited in the presence of either 1 mmol/L oleate, 10^?6 mol/L glucagon or 0.1 mmol/L TOFA (a hypolipidemic drug)—remained about fifteen-fold higher in the obese rats than in the lean rats. In contrast, ketogenesis under some conditions (oleate + TOFA) was not significantly lower (30%) as compared with the lean rats. After adaptation to the high-fat diet, lipogenesis was depressed fourfold in the lean rats and ninefold in the obese ones; however its magnitude remained significantly higher in the latter, namely at a value close to that measured in control-fed lean rats. Ketogenesis was comparable in lean and obese rats and much higher in the presence of 1 mmol/L oleate than of 0.3 mmol/L oleate, whereas lipogenesis did not vary with increasing oleate concentration in the medium. Acetyl-CoA carboxylase activity measured in liver homogenates was higher in the obese group, but was stepwise inhibited by increasing concentrations of oleyl-CoA regardless of the diet for both lean and obese rats, thus showing no abnormality of in vitro responsiveness to this inhibitor. With the control diet, hepatocyte malonyl-CoA levels were significantly higher in the obese rats, both in the basal state and after inhibition of lipogenesis by oleate and TOFA. However, after the high-fat diet, there was no longer a significant difference between the genotypes. These results show that in the obese Zucker rats, ketogenesis is dependent on hepatocyte malonyl-CoA content in the sense that their ketogenic capacity becomes “normalized” when malonyl-CoA is decreased to the levels found in the lean littermates, as it is the case after fat-feeding. This normalization of malonyl-CoA levels in spite of higher lipogenesis in the obese rats may result from the activities of enzymes of its formation and utilization.