Evaluation of the Microbact-24E bacterial identification system.

The Microbact 24E (MB24E) system is a commercial microsystem for the identification of common clinical isolates of Enterobacteriaceae and non-fermenting Gram negative bacilli, and consists of dehydrated substrates distributed in the wells of microtitre trays. This system was compared with the API20E for the identification of 386 bacterial isolates, which included 284 clinical and 102 environmental organisms. There was 97% and 91% agreement for the identification of clinical isolates of Enterobacteriaceae and other Gram negative bacilli, respectively. The identification of environmental isolates by both systems was less satisfactory. The API20E has a more extensive database than the MB24E and is thus more reliable for the identification of rare or unusual organisms, but the MB24E is cheaper, is easy and convenient to use, and is suitable for a routine microbiology laboratory.     

Application of Serum-Free Culture Medium for Preparation of A-NK Cells

To compare the differences between proliferation and cytotoxicity of adherent natural killer （A-NK） cells cultured with serum-free medium AIMV and standard serum-containing medium in vitro, and also observe the assisting effect of IL-12 on the activation and the morphology character of IL-2-treated A-NK cells, cellular proliferation was evaluated by MTT method in vitro. The morphology of the target cells killed by A-NK cells was observed through electroscope. All of the A-NK cells cultured in serum-free medium AIMV could rapidly proliferate and keep high cytotoxicity compared with that in standard serum-containing medium. A-NK cells activated by both moderate-dose IL-2 and IL-12 were superior to the high-dose IL-2-treated A-NK cells. These data indicated that serum-free medium AIMV could replace standard serum-containing medium for culturing A-NK cells, and moderate-dose IL-2 and IL-12 could reduce side effects caused by high-dose IL-2. The study provided a new experimental basis for experimental and clinical preparation of A-NK cells. Cellular ＆ Molecular Immunology.     

Production and characterization of monoclonal antibodies reactive with melatonin

Monoclonal antibodies(moAbs) reactive with melatonin(MT) were produced using MT, coupled to bovine serum albumin(BSA) with the Mannich reaction, as immunogen and conventional hybridoma techniques. Hybridoma clones secreting the moAbs were selected by an enzyme-linked immunosorbent assay system using MT-carboxymethylchitin and BSA as screening antigens. The moAbs from 6 clones were characterized by a cross-reactivity test using radioimmunoassay with 125I-labelled MT. The moAbs recognized MT but hardly recognized other analogues except for N-acetylserotonin with a crossreactivity of 0.81%. An inhibition curve for MT was obtained in the range of 50 pg to 100 ng and 1.4 ng of MT inhibited the value of the assay by half. There is interference from some unknown source in human serum.     

Preparation of Aminated Macroporous Polyvinyl Alcohol Resins and Evaluation for Bilirubin Adsorption

In the present study we prepared macroporous polyvinyl alcohol beads. A series of bilirubin adsorbents were generated by immobilization of eight amine agents to the beads as ligands. The adsorption of bilirubin was evaluated by in vitro static and dynamic adsorption tests. The results show that these adsorbents have excellent adsorption efficiency and capacity. Among the eight ligands, trimethylamine (TMA), triethylamine (TEA) and 1,6- hexanediamine(HDA) showed the highest adsorption capacity. The adsorption equilibrium can be achieved in half an hour, and the adsorption percentage of bilirubin was up to 80%. Static electricity and hydrophobic interaction played the main role in bilirubin adsorption, and the adsorption was found to match the monolayer model. The excellent adsorption of these adsorbents indicates their potential in clinical treatment.     

Pulmonary pathological features in coronavirus associated severe acute respiratory syndrome (SARS)

BACKGROUND: Severe acute respiratory syndrome (SARS) became a worldwide outbreak with a mortality of 9.2%. This new human emergent infectious disease is dominated by severe lower respiratory illness and is aetiologically linked to a new coronavirus (SARS-CoV). METHODS: Pulmonary pathology and clinical correlates were investigated in seven patients who died of SARS in whom there was a strong epidemiological link. Investigations include a review of clinical features, morphological assessment, histochemical and immunohistochemical stainings, ultrastructural study, and virological investigations in postmortem tissue. RESULTS: Positive viral culture for coronavirus was detected in most premortem nasopharyngeal aspirate specimens (five of six) and postmortem lung tissues (two of seven). Viral particles, consistent with coronavirus, could be detected in lung pneumocytes in most of the patients. These features suggested that pneumocytes are probably the primary target of infection. The pathological features were dominated by diffuse alveolar damage, with the presence of multinucleated pneumocytes. Fibrogranulation tissue proliferation in small airways and airspaces (bronchiolitis obliterans organising pneumonia-like lesions) in subpleural locations was also seen in some patients. CONCLUSIONS: Viable SARS-CoV could be isolated from postmortem tissues. Postmortem examination allows tissue to be sampled for virological investigations and ultrastructural examination, and when coupled with the appropriate lung morphological changes, is valuable to confirm the diagnosis of SARS-CoV, particularly in clinically unapparent or suspicious but unconfirmed cases.     

Recurrent and novel mutations of GCDH gene in Chinese glutaric acidemia type I families

Glutaric acidemia type I is caused by mutations of the glutaryl-CoA dehydrogenase (GCDH) gene resulting in loss of GCDH enzyme activity. Patients present with progressive dystonia and lesions in basal ganglia. Dietary treatment, when instituted from the early neonatal period, markedly reduces dystonia and morbidity. Early diagnosis and prenatal diagnosis will be facilitated by knowledge of locally prevalent GCDH mutations. Several common GCDH mutations have been found in different ethnic groups. GCDH mutations were studied in 5 Chinese glutaric acidemia type I families. We detected two novel recurrent mutations (A219T and IVS10-2A>C) which were found in two unrelated families. An asymptomatic carrier of IVS10-2A>C was also found on screening of 120 individuals. Other mutations were identified, including two other novel (R386G & IVS3+1G>A) and two known mutations (G178R & R355H). Fibroblasts from patients carrying the novel mutations were confirmed to be deficient for GCDH activity. This is the first report of GCDH mutations describing recurrent mutations in Chinese patients. The carrier rate of IVS10-2A>C may be particularly high in Chinese.     

Monoclonal antibodies against transferrin. Precipitating mixtures and lack of inter-species cross-reactivity

Five stable hybridoma lines were prepared using the myeloma cell line P3-X63-Ag.653 and spleen cells of mice hyperimmunized by pig transferrin. All hybridomas grew well in mouse peritoneal cavity and produced antibodies of the IgG₁ subclass. Antibody preparations obtained from ascitic fluids tested for their capacity of antigen precipitation. No precipitation was obtained with single antibodies and with pairs of antibodies. Three out of 10 possible triads gave clear and sharp precipitation zones and rings in immunodiffusion tests performed in agar gel. All 5 antibodies were shown by quantitative enzyme-immunoassay to be specific for pig transferrin: no cross-reaction was obtained with mouse, human, horse and sheep transferrins.     

Polymers containing enzymatically degradable bonds. VI.Hydrophilic gels cleavable by chymotrypsin

New types of hydrophilic gels based on N-(2-hydroxypropyl)methacrylamide which contain oligopeptide sequences in the crosslinks were prepared. These gels are enzymatically degradable by chymotrypsin. The rate of their degradation may be varied within a broad range by changes in the length and detailestructure of the oligopeptide sequence in the crosslinks and by changing their network density.