Growth and production characteristics of permeabilized Coleus blumei cells in immobilized fed-batch culture

Permeabilized Coleus blumei cells were cultivated in an immobilized state to study the effect of dimethyl sulfoxide (DMSO) concentrations and growth regulators on cell growth and rosmarinic acid (RA) production characteristics. Luffa (the fibrous skeleton of mature fruit of Luffa cylindrica) was a good support matrix for cell immobilization because of its high void volume. Maximum cell loading capacity was 1.33 g dry cell weight (DCW)/g dry Luffa. The experiments were done in shake flasks with no free medium. The medium was supplied in a fed-batch mode to avoid the flotation of Luffa pieces. The sucrose in the medium was completely hydrolyzed to glucose and fructose without any sugar accumulation in the medium. The cell viability was slightly higher in the cells on top of the Luffa than those in the middle. Cell growth rate and rosmarinic acid (RA) production were approximately half that obtained in cell suspension cultures. Cell yield (g DCW/g glucose) was similar to that of cell suspension cultures. The absence of growth regulators did not promote an increase of RA production but did decrease the cell mass. The second step preconditioning with 0.5% DMSO did not improve the cell's adaptability to higher DMSO concentrations and the cell mass did not increase with 2.5% DMSO.

The "count loss" artifact in Tc-99m HMPAO leukocyte SPECT of the abdomen

During SPECT studies of the abdomen with Tc-99m labeled autologous leukocytes, the authors had observed false defects involving the vertebral bodies of the lower thoracic spine in two patients. To investigate this "count loss" artifact, a phantom simulating liver, spleen, and spine was constructed. Four clinical situations were simulated by positioning cylinders in the different locations: normal spine-spleen model, normal liver-spine-spleen model, spine-enlarged spleen model, and enlarged liver-spine-enlarged spleen model. SPECT studies were performed at different concentration ratios between the spleen and the spine on the disparate models with varying distance from the spleen to the spine. The results showed that the count loss artifact is not only related to the concentration ratio between the structures but also is related to the size, position, and distance between the structures. The correction steps for this artifact include: 1) identifying average count value of the spine and spleen from ECT sinogram count data, and 2) replacing the original high-count value in the spleen by the count value close to the average value at the region of the spine in the 120 raw projection data. Using these new modified ECT data, the reconstructed orthogonal images are almost free of the count loss artifact.

Allosteric effects of a GABA receptor-active steroid are altered by stress

Recently, ring A reduced metabolites of naturally occurring steroids have been shown to act as allosteric modulators of GABA-gated chloride ion conductance. Specifically, 5 alpha-pregnane-3 alpha,21-diol-20-one (allotetrahydrodeoxycorticosterone; 5 alpha-THDOC) was shown to be a positive allosteric effector. For example, 5 alpha-THDOC enhances the specific binding of [3H]flunitrazepam, a benzodiazepine receptor agonist, among other pharmacological actions. Swim stress has been shown to reduce the ability of flurazepam, a prototypic benzodiazepine agonist, to antagonize the electrical precipitation of tonic hindlimb extension in mice. This stress-induced reduction in flurazepam's antiseizure efficacy persists for up to 72 h and is associated with alterations in the specific binding of ligands to the GABAA receptor complex. In the current study, the potentiation of [3H]flunitrazepam binding by 5 alpha-THDOC was greater in cerebral cortical membranes prepared from stressed mice compared with unstressed controls. Moreover, nanomolar concentrations of 5 alpha-THDOC that were ineffective in potentiating the specific binding of [35S]TBPS in cerebral cortical membranes prepared from unstressed control mice were capable of potentiating this binding in membranes prepared from stressed animals. Specifically, 50 nM 5 alpha-THDOC caused a 23% increase in the specific binding of [35S]TBPS in membranes from stressed mice, whereas it was without any significant effect in unstressed controls. This apparent ability of 5 alpha-THDOC to distinguish between the binding of [35S]TBPS to crude membranes prepared from stressed and unstressed control mice was eliminated in the presence of a 5 microM concentration of GABA.(ABSTRACT TRUNCATED AT 250 WORDS)

A new natural reservoir of hantavirus: isolation of hantaviruses from lung tissues of bats

Two species of bats were confirmed as new natural reservoirs of hantavirus. Antibodies to Hantaan virus were detected in 3.40% (23 of 677) of bats captured from 1989 to 1992 in Korea by the IFA technique. Areal distribution of immunofluorescent antibody were different, and seropositive rates were much high in sera of bats captured in summer (3.82%) and winter (5.82%). Viral antigens were observed in the lungs (3 of 16) and kidney (1 of 7). Two hantaviruses were isolated from lung tissues of E. serotinus and R. ferrum-equinum through a cell culture system, designated CUMC-92B8 and -92B48, respectively. Using Rous associated virus-2 reverse transcriptase-directed PCR and 2 oligonucleotide primer pairs, genomic sequences of the isolates were amplified. Amplified products of the isolates and reactivities to monoclonal antibodies very closely resembled those of Hantaan virus. These data suggest that the serotype of the isolates is closely related to Hantaan virus, and bats serve as reservoirs of hantavirus.

Pyrido[2,3-d]pyrimidine angiotensin II antagonists

A series of pyrido[2,3-d]pyrimidine angiotensin II (A II) antagonists was synthesized and tested for antagonism of A II. Compounds with a biphenylyltetrazole pharmacophore and small alkyl groups at the 2- and 4-positions of the pyridopyrimidine ring were found to be the most potent in an AT1 receptor binding assay and in blocking the A II pressor response in anesthetized, ganglion-blocked A II-infused rats. 5,8-Dihydro-2,4-dimethyl-8-[(2'-(1H-tetrazol-5-yl) [1,1'-biphenyl]-4-yl)methyl]pyrido[2,3-d]pyrimidin-7(6H)-one (4a) was one of the more potent compounds in the binding assay and was the most efficacious compound in the A II-infused rat model. Further study of 4a in Goldblatt (2K-1C) rats showed the compound to have oral bioavailability and to be an efficacious and potent compound in a high renin form of hypertension.

Small hepatocellular carcinoma: high dose internal radiation therapy with superselective intra-arterial injection of I-131-labeled Lipiodol

The aim of the present study was to deliver a high internal radiation dose to small hepatocellular carcinoma (HCC) lesions in an attempt to treat this disease. A total of 18 patients with HCC lesions measuring less than 4.5 cm in diameter (25 lesions) were treated with superselective intra-arterial injection of I-131-labeled Lipiodol (370-1,100 MBq in 3-5 ml) using a 5-F or coaxial catheter. All the lesions were nodular, multinodular, or hypervascular on pretreatment angiography. In all, 15 lesions that received over 180 Gy of cumulative radiation decreased in size in proportion to the Lipiodol retention on CT, and no pericapsular recurrence was found on angiography after 14-54 months of follow-up. In five patients who subsequently underwent surgery, 65% to 100% tumor necrosis was detected. No abnormal change in liver function tests or untoward clinical symptom of the lung, thyroid, or bone marrow was detected in patients who survived for more than 3 years after the treatment. Superselective high-dose internal radiation therapy of small HCC offers hope of treatment and long-term local control without complications.

Tumor cell-selective flow cytometric analysis for DNA content and cytokeratin expression of clinical tumor specimens by "cross-gating"

A major problem with flow cytometric analysis of clinical solid tumor specimens is that of non-malignant cell contamination which contributes to inaccurate results. Monoclonal antibody to cytokeratin, a marker for epithelial tumor (carcinoma) cells, was successfully used in conjunction with a DNA-specific dye to dually stain specimens so as to obtain DNA profiles exclusively for marker-positive tumor cells. This gating procedure was used also for analysis of the cell marker distribution for those cells having a DNA content consistent with aneuploidy. After successful verification in model systems, clinical carcinoma specimens were studied. The aneuploid population increased from a mean of 61% without gating to a mean of 81% with gating for cytokeratin. The cytokeratin-positive cell fraction increased from a mean of 55% without gating to a mean of 96% with gating for aneuploid DNA content. This gating procedure makes it possible to associate cell markers confidently with tumor cell populations, thus providing objective verification of the tissue of origin for these tumors. It can be performed simultaneously with standard gating for DNA analysis; and both procedures used together, cross-gating, are invaluable for more precise analysis of human tumor DNA and cell markers.

Rapid diagnosis of enterohemorrhagic Escherichia coli O157:H7 directly from fecal specimens using immunofluorescence stain

Serotype O157:H7 is most frequently encountered among verotoxin-producing Escherichia coli. Most laboratories use MacConkey-sorbitol agar as a screening medium. Presumptive identification of sorbitol-negative colonies is then accomplished by latex agglutination or biochemical tests with serologic confirmation, which requires 18-36 hours for completion. This study attempted to detect E coli O157:H7 directly from stool specimens by direct immunofluorescence (DIF) antibody staining to provide quicker turnaround (< 2 hours). A total of 336 abnormal fecal samples (bloody, watery, semi-liquid, or mucoid) were examined by this method. Results were compared with those of culture. Direct immunofluorescence antibody staining of the direct fecal smear detected all isolates of E coli O157 that were recovered by culture, including nonmotile strains, strains possessing the H7 flagellar antigen, and one strain with a flagellar antigen other than H7. Optimum results were achieved when specimens were pretreated with 5% bleach and centrifugation. No false-negative results were obtained with bleach-pretreated stool samples.

Intestinal parasite infections in the inhabitants along the Hantan River, Chorwon-gun

The prevalence of intestinal parasite infections in inhabitants at the reaches of the Hantan River, Chorwon-gun, Korea, was observed from August 12 to September 14, 1993. Of 465 people observed by cellophane thick smear and formalin-ether concentration method, 2 Ascaris lumbricoides (unfertilized), 1 Trichuris trichiura, 39 Clonorchis sinensis and 16 Metagonimus egg positive cases were found. After treatment, the Metagonimus egg positive cases passed out flukes of Metagonimus Miyata type. Of 68 fish caught in the Hantan River, 14 (20.6%) were infected with metacercariae of Metagonimus, while no metacercaria of C. sinensis was found. At this area, soil-transmitted nematodes are very low, but clonorchiasis and metagonimiasis are prevalent by modernate endemicity.

Reconstitution of mammalian excision repair activity with mutant cell-free extracts and XPAC and ERCC1 proteins expressed in Escherichia coli

Nucleotide excision repair in humans involves the coordinated actions of 8-10 proteins. To understand the roles of each of these proteins in excision it is necessary to develop an in vitro excision repair system reconstituted entirely from purified proteins. Towards this goal we have expressed in E. coli two of the 8 genes known to be essential for the excision reaction. XPAC and ERCC1 were expressed as fusion proteins with the Escherichia coli maltose binding protein (MBP) and purified to > 80% homogeneity by affinity chromatography. The purified proteins either as fusions or after cleavage from the MBP were able to complement the CFE of cells with mutations in the corresponding genes in an excision assay with thymine dimer containing substrate.

Thyroid scintigraphy of hyperthyroxinemia

The term "hyperthyroxinemia" encompasses clinical syndromes associated with elevated levels of thyroid hormone in the presence of increased, normal, or decreased thyroid function. The clinical presentation (i.e., history and physical examination), in vitro thyroid function tests, as well as radioisotope thyroid imaging all play key roles in the diagnosis of the underlying thyroid disorder. Many of these disorders and their appearance on thyroid scintigraphy are presented in this atlas.

Structure of human des(1-45) factor Xa at 2.2 A resolution

The structure of a large molecular fragment of factor Xa that lacks only a Gla (gamma-carboxyglutamic acid) domain (N-terminal 45 residues) has been solved by X-ray crystallography and refined at 2.2 A resolution to a crystallographic R-value of 0.168. The fragment identity was clearly established by automated Edman degradation. X-ray structure analysis confirmed the biochemical characterization and also revealed that the N-terminal epidermal growth factor (EGF)-like domain is flexibly disordered in crystals. The second EGF module, however, is positionally ordered making contacts with the catalytic domain. The overall folding of the catalytic domain is similar to that of alpha-thrombin, excluding the insertion loops of the latter with respect to simpler serine proteinases. The C-terminal arginine of the A-chain interacts in a substrate-like manner with the S1 specificity site of the active site of a crystallographically neighboring molecule. Based on this interaction and the structure of D-PheProArg methylene-thrombin, a model of the commonly used dansylGluGlyArg methylene inhibitor-factor Xa interaction is proposed. The region of factor Xa corresponding to the fibrinogen recognition site of thrombin has a reversed electrical polarity to the anion binding fibrinogen recognition site of thrombin but possesses a site similar to the Ca2+ binding site of trypsin and other serine proteinases. The structure of the C-terminal EGF domain of factor Xa is the first to be determined crystallographically. Its folding has been comprehensively compared with similar domains determined by NMR. Although the A-chain makes 44 contacts at less than 3.5 A with the catalytic domain, only 16 involve the EGF module. In addition, the A-chain makes 30 intermolecular contacts with a neighboring catalytic domain.

Health conditions among the currently employed

This report presents national estimates of the prevalence and incidence of selected health conditions and their work-related consequences among currently employed persons 18 years of age and over. The major health conditions presented include back pain; hand discomfort; dermatitis; eye, nose, and throat irritation; and work injuries. Also presented are estimates of the distribution of workers on selected physical activities and exposures at work. Data are presented by age, sex, race, ethnicity, education, and broad occupational category.