Formation of UDP-2-acetamido-2-deoxy-L-galactose and UDP-2-acetamido-2-deoxy-L-galacturonic acid by Pseudomonas aeruginosa

The O-specific polysaccharide from the lipopolysaccharide of Pseudomonas aeruginosa NCTC 8505 (IATS serotype O:3) consists of a tetrasaccharide repeating unit comprising L-rhamnose, N-acetyl-D-glucosamine (GlcNAc), bacillosamine, and N-acetyl-L-galactosaminuronic acid (L-GalNAcA) (Y. Tahara and S. G. Wilkinson, Eur. J. Biochem. 134:299-304, 1983). Incubation of GlcN or UDP-GlcNAc with cell extracts or EDTA-treated cells of P. aeruginosa NCTC 8505 yielded a mixture of UDP-ManNAc, UDP-GalNAc, UDP-GlcNAcA, UDP-ManNAcA, UDP-L-GalNAc, and UDP-L-GalNAcA. The last two compounds, here identified for the first time, may be intermediates in the synthesis of the L-GalNAcA moiety of the O-specific portion of the lipopolysaccharide of P. aeruginosa.

Cloning of Bacteroides gingivalis surface antigens involved in adherence

Despite the acknowledge importance of Bacteroides gingivalis as a periodontal pathogen, relatively little is known about the molecular basis for its pathogenicity. Recombinant DNA technology has created the opportunity to identify and characterize the virulence determinants. A Bact. gingivalis library was prepared in Escherichia coli JM83 with the vector pUC18. The library was screened for surface antigens by colony immunoblot and 337 putative surface antigen recombinants were identified. Two of these clones were found to have haemagglutinating activity. Antiserum raised against one of these clones reacted with a 43 kDa Bact. gingivalis protein that has haemagglutinating activity.

Implantation of fetal thymus and sympathetic ganglion within the anterior eye chamber in mice, to study neuro-immune interaction in thymic development

In this study 13- to 14-day fetal thymic lobes were implanted within the anterior eye chambers in mice either with or without a syngeneic newborn sympathetic ganglion. It was observed after 6 weeks of implantation that the thymic lobes that grew with the ganglia had fewer lymphoid cells than their counterparts which were grown without the ganglia. The cells that developed within the thymic lobes were Thy-1- and peanut agglutinin-positive. The thymic lobes that grew with sympathetic ganglia also showed the presence of adrenergic nerves, perhaps due to reinnervation of the thymic grafts from the ganglia.

Bacteroides gingivalis vesicles mediate attachment of streptococci to serum-coated hydroxyapatite

Outer membrane vesicles purified from Bacteroides gingivalis culture supernatant bound to serum coated hydroxyapatite (SeHA). The immobilized vesicles served as receptors for a number of species of oral streptococci. The binding of Streptococcus sanguis 12 to SeHA was increased 10 times by the vesicles. Vesicle-associated binding increased proportionally with an increase in the number of bound vesicles. Arginine and lactose both partially reduced binding of S. sanguis. Heating the vesicles destroyed their binding ability whereas heating S. sanguis reduced but did not eliminate vesicle-mediated binding.

Inhibition of rat liver microsomal estrogen 2-hydroxylase by 2-methoxyestrogens

The inhibition of estrogen 2-hydroxylase by 2-methoxyestrogens was demonstrated in screening assays and has been further investigated under initial velocity conditions. The ability of 2-methoxyestradiol and 2-methoxyestrone to block the conversion of estradiol to 2-hydroxyestradiol by male rat liver microsomal preparations was determined by measuring the release of 3H2O from [2-3H]estradiol. The apparent Kis were found to be 34.86 microM for 2-methoxyestradiol and 18.65 microM for the methoxyestrone, with the apparent Km for the substrate estradiol in these essays of 3.21 microM. Mixed inhibition studies with the methoxyestrogens and 2,4-dibromoestradiol, an effective estrogen 2-hydroxylase inhibitor, in male rat liver microsomes resulted in Dixon plots consisting of a series of parallel lines. Thus, methoxyestrogens and 2,4-dibromoestradiol are mutually exclusive inhibitors, i.e., the binding of one compound to the enzyme interferes with the binding of the other. These results indicate that the compounds are interacting at the same enzymatic site. Finally, a method utilized to measure estrogen 2-hydroxylase activity in vitro is a radioenzymatic assay involving addition of catechol o-methyltransferase (COMT) and radiolabeled S-adenosylmethionine, and the amount of catechol estrogens formed is determined by the amount of radiolabeled methoxyestrogens isolated. The results described here demonstrate inhibition of estrogen 2-hydroxylase by methoxyestrogens; however, under enzymatic conditions of low product formation, the estrogen 2-hydroxylase inhibitory effect of catechol estrogen products from the radioenzymatic assay would be insignificant. Thus, these interactions of methoxyestrogens suggest that the steroid hormonal environment be considered in the examination of estrogen 2-hydroxylase and the catechol estrogen products. off

Bacillaemia and bone marrow involvement in leprosy

Fifty patients (24 new and 26 receiving specific treatment) of leprosy were investigated to study the concentration and morphological index (MI) of the lepra bacilli in skin, peripheral blood and bone marrow. The organisms were detected in 28 cases on skin slit smear examination, in 38 cases on bone marrow examination and in 38 cases on examination of smears made from buffy coat of peripheral blood. Out of 22 cases negative for the bacilli on skin slit smears, 15 had the organisms either in buffy coat or bone marrow or both. Acid fast bacilli in peripheral blood and bone marrow with skin smear negativity were mainly observed in patients with paucibacillary type of the disease and in those who were receiving treatment. Examination of buffy coat and bone marrow for presence of lepra bacilli is suggested to establish the diagnosis in doubtful cases.

Serum glycoproteins in pulmonary tuberculosis

Serum glycoprotein levels were studied in 50 patients of pulmonary tuberculosis and 25 healthy controls. Ten of the tuberculosis patients had stage I disease, 24 stage II, 9 stage III and 7 had pulmonary tuberculosis with effusion. The serum levels of protein bound hexose, protein bound hexosamine, protein bound fucose and protein bound sialic acid were significantly higher (P less than 0.001) in patients with pulmonary tuberculosis as compared to controls; the mean values being 195.6, 189.1, 16.3 and 120.8 mg/dl respectively in patients and 117.0, 84.1, 7.7 and 67.2 mg/dl respectively in controls. The levels were not influenced by age and sex of the subjects in both groups. The levels were found to increase in all the stages of pulmonary tuberculosis with a marginal difference. Treatment with antituberculosis drugs resulted in a decrease in ESR and the various fractions of serum glycoproteins at subsequent follow up, however, the mean levels did not reach those of control subjects and were not influenced by the type of therapy.

Effects of dilazep in evolving myocardial infarction in dogs: a biochemical study

Mongrel dogs of either sex with ligation of their left anterior descending coronary artery were employed for the present study to investigate the biochemical basis of the cardioprotective action of dilazep. Dilazep (0.2 mg/kg intravenous) was administered 20 minutes after coronary arterial occlusion. Ligation of the artery for 40 minutes increased the tissue lactate concentration and decreased the adenosine triphosphate molecules within the occluded bed. Dilazep decreased the lactate concentration and improved the adenosine triphosphate content of this bed significantly. Dilazep also lowered the tissue cyclic adenosine monophosphate concentration and free fatty acid extraction of the ischemic myocardium as studied 40 minutes after coronary arterial ligation. It can be inferred that less free fatty acid extraction and calcium antagonistic action of dilazep helps in restoring mitochondrial function. Furthermore, decreased tissue lactate concentration resulted after better perfusion of the occluded bed and helped in greater generation of adenosine triphosphate molecules. These favorable biochemical and metabolic changes contribute to the cardioprotective action of dilazep.

An extension of a model for first birth interval and some social factors

"A model for the time of first birth is presented under certain assumptions, which involve biological and socio-cultural factors." The model is illustrated using data from Rural Development and Population Growth--A Sample Survey, 1978, conducted in Varanasi, India, and involving some 3,514 households.

Multiaxial orthotic hip joint for squatting and cross-legged sitting with hip-knee-ankle-foot-orthosis

In view of the importance of squatting and cross-legged sitting in the activities of daily living in Asian and African countries, a multiaxial orthotic hip joint has been developed which when fitted to a Hip-Knee-Ankle-Foot-Orthosis (HKAFO) can permit the user to squat and sit cross-legged. The design consists of a modified ball and socket joint.

Antinutritional factors of chickpea and pigeonpea and their removal by processing

Protease inhibitors, amylase inhibitors, phytolectins, polyphenols, and oligosaccarides are important antinutritional factors of chickpea and pigeonpea. Research on these factors is reviewed and compared to those in other grain legumes. Both chickpea and pigeonpea are consumed in various forms as processed food. The effects of such processing practices as cooking, germination, and fermentation to reduce the levels of these antinutritional factors are also discussed.

Comparison between serum isonicotinic acid hydrazide (INH) levels and urinary sulfadimidine (sulfamethazine) acetylation as predictors of INH acetylator status

The acetylator status of 40 children with pulmonary tuberculosis was investigated by (1) sulfadimidine (SDM; sulfamethazine) acetylation test in urine and (2) estimation of isonicotinic acid hydrazide (INH) levels. The antimode was at 70% based on the frequency distribution of SDM acetylation. Children acetylating less than 70% of administered SDM were taken as slow acetylators while those with more than 70% as rapid acetylators. The serum INH antimode was at 0.85 micrograms/ml. Thus serum values less than 0.85 micrograms/ml categorised a child as rapid and those with more than 0.85 micrograms/ml as slow acetylators. The sensitivity of these two methods was similar with a correlation coefficient r = 0.64. Thus the determination of the type of acetylator by SDM acetylation test is equally reliable and technically simpler and is recommended instead of INH serum concentration.

Parasympathetic innervation of the thymus: a histochemical and immunocytochemical study

The presence of parasympathetic nerve supply to the thymus has been demonstrated by histochemical and immunocytochemical methods using antibodies against cholineacetyl transferase. Fine nerve fibres have been observed both in the thymic parenchyma and around the blood vessels. The role of the parasympathetic nerve supply to the thymus is briefly discussed.

Lymphopoiesis in the nude fetal thymus following sympathectomy

This study was carried out to examine the innervation of the nude fetal thymus during ontogeny and to see if lymphopoietic activity would occur within these thymic lobes in the absence of sympathetic neuronal input. Fetal thymic rudiments from nu/nu mice were removed and examined for galoxylic acid-induced histofluorescence to detect the catecholaminergic nerves. Some of these lobes were organ cultured for 5 to 7 days in the presence of deoxyguanosine to eliminate any existing lymphoid cells within the rudiments. Such "nonlymphoid" thymic rudiments were implanted into the anterior eye chambers of syngenic BALB/c mice (heterozygous) from which cervical sympathetic ganglia and part of the sympathetic chain had been surgically removed (right side) one week earlier. The left side was only sham operated. The thymic implants were allowed to grow for up to 21 days on both sides; they were then removed and examined by histofluorescence, immunofluorescence, and light microscopy. The results indicate for the first time that the nude fetal thymus is innervated by sympathetic nerves and that following sympathectomy the nude thymus is able to sustain lymphopoietic activity and generate lymphoid cells which have characteristics present on thymocytes during in vivo development in normal mice, such as binding to peanut agglutinin and expression of Thy-1 antigen. The relationship between the presence of sympathetic inhibitory influence and the thymic atrophy seen in the nude mice during ontogeny, is being investigated.

Sympathetic innervation of fetal mouse thymus

This study was carried out to investigate the presence of sympathetic nerve fibers in the developing thymus. Thymic rudiments from 13 days of gestation up to birth and adult thymuses were examined by histofluorescence microscopy to detect the presence of these nerve fibers during ontogeny. Sympathetic nerve fibers were first visible around day 17 of gestation and increased in density and distribution by the time of birth and in the adult thymus. The appearance of immunoreactive cells about the same time as the presence of nerve fibers in the thymic rudiments has been discussed in light of a regulatory role for the sympathetic neuronal input on the maturation of thymocytes during ontogeny.

Changes in the surface morphologies of the cells in the bursa cloacalis (bursa of Fabricius) and thymus during ontogeny of the chick embryo

Slices or sections through the bursa cloacalis and thymus of chick embryos at 7-21 days of incubation were observed by light and electron microscopy to determine whether major differences existed in the surface morphologies of lymphoid cells in these organs, and whether the surface morphologies of these cells changed during ontogeny. These organs were fixed concurrently and identically at each stage. The thymus was packed at all stages with spherical cells having fine structures characteristic of those of lymphoid cells. Many irregularly shaped, epithelial cell processes were present between lymphoid cells. The bursa contained many irregularly shaped stromal cells as well as spherical cells. The latter were few in number during early development, but became the predominant type of cell near the end of incubation. Spherical cells in the bursa consisted of three types based on fine structure: lymphoid cells, granulocytic cells, and cells which were probably precursors of granulocytic cells. Spherical cells in the bursa could not be classified into these three types by their surface morphologies, however, because the latter at any one stage of development were similar. At 7-8 days of incubation, spherical cells in the bursa could not be differentiated consistently from neighboring stromal cells by scanning electron microscopy alone, but by 9 days, spherical cells could be identified routinely by this method. At 9-10 days of incubation, only minor differences existed in the surface morphologies of the spherical cells in the bursa and thymus: Bursal cells displayed long, ridgelike processes, whereas thymic cells exhibited fine surface undulations and large blebs. At 11 days, the surfaces of the spherical cells in the bursa were covered by numerous short microvilli, but the surfaces of thymic cells were unchanged. Bursal cells retained their microvilli through 14 days of incubation, but between 15 and 21 days progressively lost their microvilli, becoming essentially bald near the end of this period. Likewise, thymic cells gradually lost their surface wrinkles and blebs. Near the time of hatching, both types of cells were smooth-surfaced and tightly packed, with individual cells assuming polyhedral configurations.

In vitro lymphopoiesis in foetal thymic organ cultures: effect of various agents

In this study 14-day-old foetal BALB/c mouse thymic lobes were removed and grown as organ culture in vitro for up to 6 days. The cultures were treated with agents which are known to alter the intracellular levels of cyclic nucleotides. The proliferative response of the lobes was judged by histological examination, 125I-UdR uptake and cell yields, of the lobes at various time intervals. The results indicate that agents which raise cyclic GMP levels stimulate the proliferative response of the lobes as judged by the various parameters used and that the response was largely restricted to the lymphoid cells. It has been suggested that most probably cyclic GMP is the positive signal for thymic lymphopoiesis perhaps not only in vitro but also in vivo.

Effect of catecholamines on lymphopoiesis in fetal mouse thymic explants

Fetal thymic explants (14 days of gestation) from Balb/c mice were grown in organ culture for up to 12 days and the pattern of lymphopoiesis was monitored by 125IUdR incorporation and cell yields of such lobes in the presence of adrenergic agents. It was observed that, after 3 days of cultures, phenylephrine stimulated lymphopoiesis in thymic explants, whereas some inhibition was observed with isoproterenol. These observations were confirmed by autoradiography. It was also observed that cells obtained from phenylephrine-treated cultures had greater mitogen reactivity than either control (untreated) or isoproterenol-treated cultures. The possible role of cyclic nucleotides as intracellular mediators of thymocyte maturation is discussed.

In vitro studies on the ontogeny of lymphocyte populations

We have investigated the ontogency of lymphocyte populations in the mouse embryo using organ culture techniques. Our results indicate that B lymphocytes are generated independently in foetal liver, foetal spleen and foetal bone marrow, while T lymphocytes are generated in thymus. We have characterised the structural and functional properties of developing lymphocytes in the organs. Our results suggest that foetal lymphocytes may differ from adult lymphocytes in a number of important respects which may have a bearing on the generation of tolerance to self antigens.