Major differences between the testis and epididymis in the induction of granulomas in response to extravasated germ cells. I. A light microscopical study in mice

A spermatic granuloma is a chronic inflammatory lesion which surrounds extravasated spermatozoa. Clinically, the lesion develops in the interstitial spaces of the epididymis and vas deferens, and only exceptionally in the testis itself. In the present study, murine testes and epididymides were injured using a needle and the histological appearances of these organs was then compared. Traumatic injury induced extravasation of germ cells in both testes and epididymides. A few days later, spermatic granulomas consistently formed in the epididymides, however, such lesions were not induced in the testes. To examine the possibility that epididymal spermatozoa have inherently greater ability to form spermatic granulomas than do testicular germ cells, isolated epididymal spermatozoa or testicular germ cells were locally injected into the testes and epididymides of recipient mice. Spermatic granulomas readily formed in the epididymides after local injection of either epididymal spermatozoa or testicular germ cells. In contrast, such lesions did not form in the testes even when epididymal spermatozoa were injected. Therefore, this study suggests that the microenvironment of the testicular interstitium, rather than the extravasated components from the ruptured seminiferous tubules, is the main factor determining the limited formation of spermatic granulomas in the testis.

Chemokine responses and accumulation of inflammatory cells in the lungs of mice infected with highly virulent Cryptococcus neoformans: effects of interleukin-12

We examined the mechanisms involved in the development of lung lesions after infection with Cryptococcus neoformans by comparing the histopathological findings and chemokine responses in the lungs of mice infected with C. neoformans and assessed the effect of interleukin (IL) 12 which protects mice from lethal infection. In mice infected intratracheally with a highly virulent strain of C. neoformans, the yeast cells multiplied quickly in the alveolar spaces but only a poor cellular inflammatory response was observed throughout the course of infection. Very little or no production of chemokines, including MCP-1, RANTES, MIP-1alpha, MIP-1beta and IP-10, was detected at the mRNA level using RT-PCR as well as at a protein level in MCP-1, RANTES and MIP-1alpha. In contrast, intraperitoneal administration of IL-12 induced the synthesis of these chemokines and a marked cellular inflammatory response involving histiocytes and lymphocytes in infected mice. Our findings were confirmed by flow cytometry of intraparenchymal leukocytes obtained from lung homogenates which showed IL-12-induced accumulation of inflammatory cells consisting mostly of macrophages and CD4+ alphabeta T cells. On the other hand, C-X-C chemokines including MIP-2 and KC, which attract neutrophils, were produced in infected and PBS-treated mice but treatment with IL-12 showed a marginal effect on their level, and neutrophil accumulation was similar in PBS- and IL-12-treated mice infected with C. neoforman. Our results demonstrate a close correlation between chemokine levels and development of lung lesions, and suggest that the induction of chemokine synthesis may be one of the mechanisms of IL-12-induced protection against cryptococcal infection.

The cloning of plant E2F, a retinoblastoma-binding protein, reveals unique and conserved features with animal G(1)/S regulators

Association of the retinoblastoma (Rb) protein with E2F transcription factors is central to cell cycle-specific gene expression and growth in animal cells. Whether Rb-E2F complexes are also involved in plant cell growth and differentiation is still unknown since E2F proteins have not yet been identified in plants. Here we report the isolation and characterisation of a wheat E2F (TmE2F) cDNA clone. Interestingly, the overall domain organisation of plant E2F is related to the human E2F-1/2/3 subset but its primary sequence is slightly more related to the E2F-4/5 subset. TmE2F-Rb binding depends on residues, located at the C-terminus, which are different from those of animal E2Fs. However, the acidic or hydrophobic nature of certain residues is maintained, strongly suggesting that they may have a crucial role in E2F activities. Plant E2F is expressed in proliferating cultured cells and in differentiated tissues and is up-regulated early in S phase. Our studies reinforce the idea that G(1)/S regulators in plants are unrelated to those of yeast cells but similar to those of animal cells and provide new tools to analyse the links between cell cycle regulators, plant growth and developmental signals.

Surgical treatment of patent ductus arteriosus (PDA) through mini subaxillary extrapleural approach

In this study, a new surgical technique for the surgical treatment of patent ductus arteriosus (PDA) is evaluated. The subaxillary extrapleural approach was performed on 836 patients with patent ductus arteriosus. And 20 of these patients were evaluated for postoperative outcomes compared with the routine technique. The results indicated that the new method is safe, less traumatic and has better cosmetic effects. It is concluded in this article that the subaxillary extrapleural approach for PDA is a good modification to the routine surgical technique, that is surgery through the posterolateral approach.

Association of edentulousness with systemic factors in elderly people living at home

OBJECTIVE

To examine the association of edentulousness with systemic factors: age, gender, tobacco-smoking, alcohol intake, body mass index, functioning in daily living, cortical thickness at the mandibular angle, and systemic diseases: bone-fracture (an indicator for osteoporosis), diabetes, thyroid disease, hyperparathyroidism, asthma, heart failure, hypertension.

METHODS

The study population comprised 293 elderly subjects, 124 (42%) edentulous and 169 (58%) dentate. The data from clinical and radiographic examinations and structured interviews were analyzed by multiple logistic regression.

RESULTS

When edentulousness in both the mandible and the maxilla was considered, history of bone fracture and tobacco-smoking were significantly related to complete edentulousness with odds ratios (OR) of 2.51 (95% CI: 1.47-4.28) and 2.42 (95% CI: 1.32-4.43) respectively, associations independent of age and gender. A similar association was found for the edentulous mandible. In the elderly subjects with an edentulous maxilla, besides the significant factors of history of bone fracture and tobacco-smoking, asthma was also associated with edentulousness at an odds ratio of 10.81 (95% CI: 1.38-84.66), oldest subjects most often being edentulous (OR: 2.23, 95% CI: 1.13-4.39). Diabetes was not related to edentulousness either in the mandible or in the maxilla.

CONCLUSIONS

The finding of associations of history of bone fracture, tobacco-smoking, and asthma with edentulousness emphasizes the association of systemic conditions with edentulousness. Advanced age was related to an edentulous maxilla. The relationship between asthma and total tooth loss in the maxilla might suggest a local oral effect of medications used by asthmatic patients.

A monoclonal antibody to ICP4 of MDV recognizing ICP4 of serotype 1 and 3 MDV strains

Monoclonal antibodies (MAbs) were prepared against ICP4 of Marek's disease virus (MDV). Mice were inoculated with ICP4 obtained from High-Five insect cells infected with a recombinant baculovirus expressing ICP4. MAbs were selected by enzyme-linked immunosorbent assay (ELISA) using MDV-infected and control chick kidney cells as antigens. One of the MAbs, 5H8, recognized an epitope toward the carboxyl terminus of ICP4 based on staining of reticuloendotheliosis virus-transformed cells transfected with full-length and truncated ICP4 constructs. This MAb recognized ICP4 in chicken embryo fibroblasts (CEFs) infected with MDV strains JM16 and HVT but not with SB-1 strain. Using Western blot analysis a protein of 155 kDa was detected in CEFs infected with JM16 and HVT strains.

[Gene frequency of HPA among Hunan population of Han nationality]

We used allele specific primer PCR (ASP-PCR) method to detect the genotype of five major HPA systems among Hunan population of Han nationality. The results showed: The gene frequency of PLA1 was 81.00% and 85.87% for Kob, 71.00% for Baka, 91.00% for Pena, 90.67% for Brb which provided the basis for further clinical application of HPA.

The structural and functional analysis of the hemoglobin D component from chicken

Oxygen binding by chicken blood shows enhanced cooperativity at high levels of oxygen saturation. This implies that deoxy hemoglobin tetramers self-associate. The crystal structure of an R-state form of chicken hemoglobin D has been solved to 2.3-A resolution using molecular replacement phases derived from human oxyhemoglobin. The model consists of an alpha2 beta2 tetramer in the asymmetric unit and has been refined to a R-factor of 0.222 (R-free = 0.257) for 29,702 reflections between 10.0- and 2.3-A resolution. Chicken Hb D differs most from human oxyhemoglobin in the AB and GH corners of the alpha subunits and the EF corner of the beta subunits. Reanalysis of published oxygen binding data for chicken Hbs shows that both chicken Hb A and Hb D possess enhanced cooperativity in vitro when inositol hexaphosphate is present. The electrostatic surface potential for a calculated model of chicken deoxy-Hb D tetramers shows a pronounced hydrophobic patch that involves parts of the D and E helices of the beta subunits. This hydrophobic patch is a promising candidate for a tetramer-tetramer interface that could regulate oxygen binding via the distal histidine.

GRAB proteins, novel members of the NAC domain family, isolated by their interaction with a geminivirus protein

Geminiviruses encode a few proteins and depend on cellular factors to complete their replicative cycle. As a way to understand geminivirus-host interactions, we have searched for cellular proteins which interact with viral proteins. By using the yeast two-hybrid technology and the wheat dwarf geminivirus (WDV) RepA protein as a bait, we have isolated a family of proteins which we termed GRAB (for Geminivirus Rep A-binding). We report here the molecular characterization of two members, GRAB1 and GRAB2. We have found that the 37 C-terminal amino acids of RepA are required for interaction with GRAB proteins. This region contains residues conserved in an equivalent region of the RepA proteins encoded by other viruses of the WDV subgroup. The N-terminal domain of GRAB proteins is necessary and sufficient to interact with WDV RepA. GRAB proteins contain an unique acidic C-terminal domain while their N-terminal domain, of ca. 170 amino acids, are highly conserved in all of them. Interestingly, this conserved N-terminal domain of GRAB proteins exhibits a significant amino acid homology to the NAC domain present in proteins involved in plant development and senescence. GRAB1 and GRAB2 mRNAs are present in cultured cells and roots but are barely detectable in leaves. GRAB expression inhibits WDV DNA replication in cultured wheat cells. Our studies highlight the importance that the pathway(s) mediated by GRAB proteins, as well as by other NAC domain-containing proteins, might have on geminivirus DNA replication in connection to plant growth, development and senescence pathways.

[Optimum choice for the cultivation of CFU-GM in media buffered with HEPES]

The effects of media buffered with HEPES of different concentrations and different incubation periods on the proliferation and differentiation of CFU-GM were studied under the standard condition for culture. The results exhibited that when the incubation period prolonged, the pH values of culture system raised and the colony formation of CFU-GM decreased; the culture system added with proper HEPES buffer solution could maintain and increase the colony formation of CFU-GM, especially the culture system in which the pH value was not adjusted before the experiment. We also found that media buffered with HEPES could change the ratio of different colony types. This showed that media buffered with HEPES could not only stimulate the proliferation of CFU-GM, but also affect its differentiation. The results suggest that media buffered with HEPES are better than those without HEPES for the culture of hematopoietic progenitor cells, and the optimum concentration is 10-20 mmol.L-1.

Evaluation of pulmonary afferent fibers in the nucleus tractus solitarius: a horseradish peroxidase and c-fos like immunohistochemical study in the rat

Wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) was injected into the rat lung parenchyma, just beneath the lateral surface of the left upper lobe, in order to demonstrate the pulmonary afferents. This injection resulted in heavy accumulation of labeled fibers in the medial nucleus tractus solitarius (NTS). The labeling in the medial NTS was divided into the ventral and dorsal parts at the level around the obex. Some labeling was found in the commissural and ventrolateral NTS. Further confirmation of the central distribution of these pulmonary afferent fibers was made by the expression of fos-like immunoreactivity (FOS-LI) induced by injection of formalin into the lung. It is concluded that afferents of lung parenchyma terminating predominantly in the medial NTS might come from alveoli and terminal bronchioles, because WGA-HRP and formalin injected into the lung are considered to be confined to the terminal areas of the respiratory tract.

Synthesis and immunosuppressant activity of pyrazole carboxamides

A series of novel pyrazole carboxamides is disclosed that demonstrate strong immunosuppressant activity in rodent and human mixed leukocyte response (MLR) assays (IC50 < 1 microM). The synthesis, biological activity, mode of action, and pharmacokinetic properties of this new lead series are discussed.

Discovery of ascomycin analogs with potent topical but weak systemic activity for treatment of inflammatory skin diseases

Drug therapy for the major inflammatory skin diseases, which include atopic dermatitis, psoriasis and allergic contact dermatitis, is often inadequate due to poor efficacy, toxicity, or both. Much research has focused on the macrolactam T cell inhibitors as a promising new class of agents for immunotherapy, and medicinal chemistry efforts to design novel ascomycin analogs have produced clinically promising agents. A synthetic program to modify the ascomycin nucleus to alter its physicochemical properties and promote systemic clearance is described. A biologic screening strategy to identify analogs with reduced systemic activity and rapid pharmacokinetic elimination led to identification of the clinical candidate, ABT-281. A swine contact hypersensitivity model was used as a stringent indicator of skin penetration as human doses of topical corticosteroids produced inhibition only in the 50% range and ED50 values were 100-fold less potent than in rat. Also, cyclosporine was confirmed to be topically inactive in swine, as seen in human. ABT-281 had topical potency equal to tacrolimus (FK506) despite a severalfold lower potency for inhibiting swine T cells in vitro, consistent with superior skin penetration. ABT-281 was found to have a shorter duration of action after i.v. dosing in monkeys using an ex vivo whole blood IL-2 production assay. Systemic potency was reduced by 30-fold or more in rat popliteal lymph node hyperplasia and contact hypersensitivity assays. Following i.v. or i.p. administration in the swine contact hypersensitivity model, ABT-281 was 19- and 61-fold less potent, respectively, than FK506. Pharmacokinetic studies showed that ABT-281 had a shorter half life and higher rate of clearance than FK506 in all three species. The potent topical activity and reduced systemic exposure of ABT-281 may thus provide both efficacy and a greater margin of safety for topical therapy of skin diseases.

Occlusion of the femoral artery induced fos-like immunoreactive neurons in the lateral habenular nucleus projecting to the midbrain periaqueductal gray in the rat

Wheat germ agglutinin conjugated horseradish peroxidase (WGA-HRP) injection into the midbrain periaqueductal gray (PAG) resulted in heavy accumulation of retrogradely labeled neurons in the lateral habenular nucleus (LHb) bilaterally. When the left femoral artery was persistently ligated for 2 h, the expression of Fos-like immunoreactivity (FOS-LI) was also found bilaterally in the LHb. In the present study, by combining the retrograde labeling method of injecting WGA-HRP into the PAG and the immunohistochemical staining of the FOS-LI neurons in the LHb induced by occlusion of the femoral artery, it was demonstrated that there are neurons containing both HRP labeling and FOS-LI. These neurons appeared to be located mainly in the medial part and posterior half of the LHb, and constitute about 24% of the total number of all labeled cells.

Distribution of F4/80-positive cells in developing ovaries in the mouse

The mature ovary contains a large number of macrophages. In the present study, the distribution of macrophages in murine ovaries at various developmental stages was immunohistochemically studied using a monoclonal antibody against F4/80, a highly specific antigen of murine macrophages. The results showed that definite F4/80-positive stains were hardly detectable in ovaries on day 0 after birth. On day 7, a few F4/ 80-positive cells could be identified between the developing follicles. The positive stains were irregular in shape and showed little physical contact with the primordial or primary follicles. By days 14 and 21, when the theca cell layers of growing follicles were developing, the positive cells had extended or elongated to surround the cell layer. On day 28, besides the presence of elongating positive cells surrounding the growing follicles, irregularly shaped F4/80-positive cells became apparent in the interstitium between the growing follicles and also in the capsular tissues. Thereafter, positive cells with stellate appearance were detected in the corpora lutea, which first developed around 6 weeks of age. Although the positive cells were homogenously distributed in the corpora lutea in virgin adults, only a few sporadic positive cells were found there in pregnant mice. However, the positive cells infiltrated into the corpora lutea again in the postpartum period. These results show that ovarian macrophages exhibit dramatical changes in their distribution from neonatal to postpartum periods.

Brainstem projections of sensory fibers of the lung: a horseradish peroxidase and c-fos-like immunohistochemical study in the rat

The brainstem projections of sensory fibers of the lung were determined in the rat by using the horseradish peroxidase (HRP) and c-fos immunohistochemical methods. Wheat germ agglutinin conjugated HRP (WGA-HRP) was injected into the parenchyma of the upper lobe of the left lung. This injection resulted in anterograde labeling in the nucleus of the tractus solitarius (NTS), area postrema (AP) and external cuneate nucleus (ECu) with slightly ipsilateral predominance. It was of interest that these labeled sensory fibers are heavily accumulated in the medial subnucleus at the rostral pole of the NTS and in the commissural subnucleus at the caudal pole. In particular, labeled fibers in the medial subnucleus were characterized by division into the ventral and dorsal portions. After formalin was injected into the parenchyma of the upper lobe of the left lung, the expression of c-fos-like immunoreactivity (FOS-LI) was observed in three nuclei of the brainstem mentioned above. In addition, this experiment resulted in the expression in the ventrolateral medulla, nucleus raphe pallidus and dorsal motor nucleus of vagus nerve bilaterally. With respect to the number of the immunoreactive cells, we could draw the conclusion that the most optimum time to induce the expression of FOS-LI is between 1.5 h and 2.0 h after noxious stimuli.

Patterns of efferent lymphatics of the mouse testis

Previous studies in the rat demonstrated that lymph vessels arise from various sites in the testis and then anastomose to form the main lymph trunk toward the testicular artery. Although mice are as commonly used in the laboratory as the rat, precise knowledge concerning their testicular lymphatics has not been established. In the present study, the patterns of testicular lymphatic drainage in the mouse were examined using local injection of India ink into the testicular parenchyma. The results demonstrated that, besides the lymph trunk surrounding the testicular artery, a lymphatic drainage route running along the ductus deferens is also present.

Effects of age on the posttranscriptional regulation of CCAAT/enhancer binding protein alpha and CCAAT/enhancer binding protein beta isoform synthesis in control and LPS-treated livers

The CCAAT/enhancer binding protein alpha (C/EBPalpha) and CCAAT/enhancer binding protein beta (C/EBPbeta) mRNAs are templates for the differential translation of several isoforms. Immunoblotting detects C/EBPalphas with molecular masses of 42, 38, 30, and 20 kDa and C/EBPbetas of 35, 20, and approximately 8.5 kDa. The DNA-binding activities and pool levels of p42(C/EBPalpha) and p30(C/EBPalpha) in control nuclear extracts decrease significantly whereas the binding activity and protein levels of the 20-kDa isoforms increase dramatically with LPS treatment. Our studies suggest that the LPS response involves alternative translational initiation at specific in-frame AUGs, producing specific C/EBPalpha and C/EBPbeta isoform patterns. We propose that alternative translational initiation occurs by a leaky ribosomal scanning mechanism. We find that nuclear extracts from normal aged mouse livers have decreased p42(C/EBPalpha) levels and binding activity, whereas those of p20(C/EBPalpha) and p20(C/EBPbeta) are increased. However, translation of 42-kDa C/EBPalpha is not down-regulated on polysomes, suggesting that aging may affect its nuclear translocation. Furthermore, recovery of the C/EBPalpha- and C/EBPbeta-binding activities and pool levels from an LPS challenge is delayed significantly in aged mouse livers. Thus, aged livers have altered steady-state levels of C/EBPalpha and C/EBPbeta isoforms. This result suggests that normal aging liver exhibits characteristics of chronic stress and a severe inability to recover from an inflammatory challenge.

[Preliminary experiment on selection of oral hygienic cleanser]

The effectiveness of three commercial chewing gums ("Hua Aikang","Cao Shanhu" and "Poli") and brushing with toothpaste on the elimination of dental plaque was observed in 31 healthy males (aged 19-25 years). Before and after chewing or brushing, evaluation of oral taste and examination of plaque were performed. The result showed that the oral taste after chewing, "hua aikang" was the best, then "po li" and "cao shanhu"; plaque indexes were substantially reduced by all four kinds of treatment (P < 0.001) as compared with the pretest values, however "hua aikang" demonstrated a better effectiveness (P < 0.001). It also indicates that plaque index is an important index revealing the hygiene status.

The maize retinoblastoma protein homologue ZmRb-1 is regulated during leaf development and displays conserved interactions with G1/S regulators and plant cyclin D (CycD) proteins

Recent discoveries of plant retinoblastoma (Rb) protein homologues and D-type cyclins suggest that control of the onset of cell division in plants may have stronger parallels with mammalian G1/S controls than with yeasts. In mammals, the Rb protein interacts specifically with D-type cyclins and regulates cell proliferation by binding and inhibiting E2F transcription factors. However, the developmental role of Rb in plants and its potential interaction with cell cycle regulators is unknown. We show that the maize Rb homologue ZmRb-1 is temporally and spatially regulated during maize leaf development. ZmRb-1 is highly expressed in differentiating cells, but almost undetectable in proliferating cells. In vitro, both ZmRb-1 and human Rb bind all classes of plant D-type cyclins with the involvement of a conserved N-terminal Leu-x-Cys-x-Glu (LxCxE) Rb-interaction motif. This binding is strongly reduced by mutation of the conserved Cys-470 of ZmRb-1. ZmRb-1 binds human and Drosophila E2F, and inhibits transcriptional activation of human E2F. We also show that ZmRb-1 is a good in vitro substrate for all human G1/S protein kinases. The functional conservation of proteins that control the G1/S transition in mammals and plants points to the existence of plant E2F homologues. We conclude that evolution of Rb and cyclin D proteins occurred after separation of the fungi from the higher eukaryotic lineage, but preceded the divergence of plant and animal kingdoms.

Postnatal development of Leydig cells in the opossum (Monodelphis domestica): an immunocytochemical and endocrinological study

This study involved characterization of Leydig cells of the opossum Monodelphis domestica, functionally by immunocytochemical identification of the enzyme 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) and by measurement of testosterone levels using RIA. Immunostaining for 3 beta-HSD was first detected in a few Leydig cells on Day 16, was increased by Day 24, reached a peak at 4 mo, and was present even in senescent (3 yr) animals. Plasma testosterone was first measurable (0.35 nM) at prepuberty (3.5 mo). Prior to that, plasma testosterone concentrations were uniformly below the level of detection (< 0.3 nM) in both sexes from Day 5 to 2.5 mo. By 4 mo (puberty), plasma testosterone levels in males had risen significantly to 1.53 +/- 0.35 nM, continuing to increase to 1.79 +/- 0.4 nM at 6 mo and peaking at 2.71 +/- 0.29 nM in the adult (1-2 yr). Ovarian testosterone concentrations were consistently lower than those in the testis, as were those of adrenals of both sexes. Thus the testis would appear to be the major source of androgen production throughout life in this species. Our immunocytochemical study suggests that in Monodelphis, puberty is reached at 4 mo, and this was further supported by a rise in circulating testosterone levels at this time.

Essential pathogenic role for endogenous interferon-gamma (IFN-gamma) during disease onset phase of murine experimental autoimmune orchitis. I. In vivo studies

We previously found that immunization of CH3/He male mice with syngeneic testicular germ cells (TGC) without the aid of any adjuvants was sufficient to induce DTH to TGC and experimental autoimmune orchitis (EAO). To evaluate the role of endogenous IFN-gamma in this model, C3H/He mice immunized subcutaneously with TGC on days 0 and 14 received a single injection of anti-murine IFN-gamma MoAb on day 15, 20 or 25. On day 45, DTH to TGC was tested, testis specimens were collected for histological examination, and blood samples collected for IFN-gamma measurement. The results showed that whilst MoAb treatment on day 15 or 25 did not influence DTH responses, EAO development, and appearance of IFN-gamma in the circulation, treatment on day 20 significantly suppressed all of them. Thus, a single injection with anti-IFN-gamma MoAb may successfully down-regulate testicular autoimmunity, provided that the treatment is given at an optimal time point during disease development.

Estimation of the numerical densities of neurons and synapses in cerebral cortex

In this paper we discuss a stereological technique, 'the unfolding method', for a quantitative study of the nervous system [1,31]. Stereology implies a geometric analysis of structures and textures, and is a method to derive directly metric properties of structures from two-dimensional sections on the basis of geometrico-statistical reasoning [36,37]. Recent advances in the stereological method allow quantitative analysis [8,19,27,32]. Images on sections provide only two-dimensional information, but the stereological method can offer three-dimensional and quantitative information [19]. The need for quantitative analysis is more important and useful in the central nervous system (CNS) than in other organs. Two functional units, neurons and synapses, are of particular interest in evaluating CNS function. Numerical densities of neurons and synapses in rat visual cortex were estimated using the unfolding method at light and electron microscopic levels, respectively. Once the numerical densities of neurons and synapses were obtained, synapse-to-neuron ratios could be calculated. The ratios are interpreted as a means to obtain an index of interneuronal connectivity [9]. The unfolding method may become a powerful strategy in neuroscience research when numerical estimates are performed in restricted areas such as cortical layers II-IV, because this method is less time-consuming than other stereological methods [6,21,22].

A novel antioxidant gene from Mycobacterium tuberculosis

Among the major antimicrobial products of macrophages are reactive intermediates of the oxidation of nitrogen (RNI) and the reduction of oxygen (ROI). Selection of recombinants in acidified nitrite led to the cloning of a novel gene, noxR1, from a pathogenic clinical isolate of Mycobacterium tuberculosis. Expression of noxR1 conferred upon Escherichia coli and Mycobacterium smegmatis enhanced ability to resist RNI and ROI, whether the bacteria were exposed to exogenous compounds in medium or to endogenous products in macrophages. These studies provide the first identification of an RNI resistance mechanism in mycobacteria, point to a new mechanism for resistance to ROI, and raise the possibility that inhibition of the noxR1 pathway might enhance the ability of macrophages to control tuberculosis.