[Dynamic assay of oleanolic acid in Aralia taibaiensis Z. Z. Wang et H. C. Zheng]

The dynamic assay on oleanolic acid (OA) in Aralia taibaiensis shows that the plant has a higher OA level. The level in root cortex is 4.74%-10.81% and peak stages are mid-May to late June and late August to mid-September the level in stem barks is 3.59%-12.06% and peak period is between mid-May and late July, the level in leaves increases throughout the life time ranging from 2.41% to 6.66% and peak level is 6.66% around mid-September.

[Cloning and sequencing the isopenicillin N synthetase(IPNS) gene from Streptomyces cattleya]

Great homology existed between IPNS genes from surphur-containing beta-lactam antibiotics producers including procaryotes and eucaryotes. A DNA homologous band was confirmed in S. cattleya by Southern blot analysis using IPNS gene from S. lipmanii as a probe. A recombinant plasmid containing the cyclase gene involved in thienamycin biosynthesis and IPNS gene was obtained by complementary cloning with mutant from S. cattleya. DNA sequencing revealed that the IPNS gene of S. cattleya consists of 963 bp encoding a protein of 321 amino acids with ATG as start codon, TGA as stop codon. Pairwise comparison of the predicted amino acid sequences showed 56% and 64% similarity with IPNSs of S. clavuligerus and S. lipmanii, respectively.

Deficiencies in progenitor cells of multiple hematopoietic lineages and defective megakaryocytopoiesis in mice lacking the thrombopoietic receptor c-Mpl

Mice with a null mutation in the thrombopoietin (TPO) receptor c-Mpl were generated by gene targeting. c-mpl-deficient mice developed normally but were deficient in megakaryocytes and severely thrombocytopenic. The hematocrit and numbers of mature circulating leukocytes were normal in mpl-/- mice, as was the distribution of morphologically identifiable precursors in hematopoietic tissues. Bone marrow and spleen cells of adult mpl-/- mice lacked specific binding sites for TPO, were unresponsive to TPO in culture, and displayed a marked deficiency in progenitor cells with megakaryocytic potential. Significantly, total hematopoietic progenitor cell numbers were also reduced in mpl-/- mice including multipotential, blast cell, and committed progenitors of multiple lineages. The megakaryocyte deficiency was evident as early as 14 days of gestation in mpl-deficient mice, although reductions in progenitor cell numbers arose only later in development. The data suggest that the critical function of c-Mpl signalling in megakaryocytopoiesis is in maintenance of mature megakaryocyte numbers through control of progenitor cell proliferation and maturation. Moreover, our results also imply an important role for TPO and c-Mpl in the production of primitive pluripotent progenitor cells as well as progenitor cells committed to nonmegakaryocytic lineages.

Identification of Gas6 as a growth factor for human Schwann cells

Schwann cells are one of the principal components of the peripheral nervous system. They play a crucial role in nerve regeneration and can be used clinically in the repair of injured nerves. We have established serum-free, defined culture conditions that rapidly expand adult human Schwann cells without fibroblast growth. We find that Gas6, a ligand for the Axl and Rse/Tyro3 receptor protein tyrosine kinase family, stimulates human Schwann cell growth, increasing both cell number and thymidine incorporation. Gas6 has synergistic effects with the other known human Schwann cell mitogens, heregulin/glial growth factor and forskolin. Addition of Gas6 causes phosphorylation of Axl and Rse/Tyro3 simultaneously and results in ERK-2 activation. A combination of Gas6 with heregulin and forskolin, on a defined background, supports maximal Schwann cell proliferation, while preserving the typical Schwann cell morphology and expression of the Schwann cell markers S-100, glial fibrillary acidic protein, and low-affinity nerve growth factor receptor. Gas6 mRNA is present in both spinal motor neurons and large neurons of the dorsal root ganglia, and neural injury has been reported to upregulate Rse/Axl in the schwann cell. This is the first demonstration of a potentially important biological role for the human Gas6/Rse-Axl system.

Increased plasma rifabutin levels with concomitant fluconazole therapy in HIV-infected patients

OBJECTIVE

To determine the effect of fluconazole on rifabutin pharmacokinetics.

DESIGN

An open-label, crossover, phase 1 trial.

SETTING

Outpatient clinical research center at a university medical center in Washington, D.C.

PATIENTS

12 persons with human immunodeficiency virus (HIV) infection whose CD4 lymphocyte counts were between 200 and 500 cells/mm3 and who were receiving maintenance therapy with zidovudine.

INTERVENTION

Fluconazole, 200 mg/d for 2 weeks; then a combination of fluconazole, 200 mg/d, and rifabutin, 300 mg/d, for 2 weeks; and then rifabutin, 300 mg/d, for the final 2 weeks of the study.

MEASUREMENTS

Blood and urine samples were obtained at regular intervals for 24 hours at the end of each 2-week dosing period to ascertain concentrations of fluconazole and rifabutin and the 25-desacetyl metabolite of rifabutin, LM565.

RESULTS

Fluconazole significantly increased the plasma concentrations of both rifabutin and LM565. Mean increases in the area under the plasma concentration curve compared with the time curve over a 24-hour dosing interval were 82% (5442 +/- 2404 ng.h/mL compared with 3025 +/- 1117 ng.h/mL; P less than or equal to 0.05) for rifabutin and 216% (959 +/- 529 ng.h/mL compared with 244 +/- 141 ng.h/mL; P less than or equal to 0.05) for LM565.

CONCLUSIONS

Fluconazole significantly increases the systemic exposure of both rifabutin and LM565. This pharmacokinetic interaction offers a mechanism that may explain the changes reported in both the efficacy and toxicity of rifabutin with concomitant fluconazole therapy.

Subcellular distribution of p21 and PCNA in normal and repair-deficient cells following DNA damage

BACKGROUND

The p21 protein binds to both cyclin-dependent kinases (Cdks) and the proliferating cell nuclear antigen (PCNA). In mammalian cells, DNA damage results in an increase in the level of p53 protein, which stimulates expression of the gene encoding p21, which in turn leads to an inhibition of Cdk activity. Biochemical studies have shown that the direct interaction between p21 and PCNA blocks the latter's function in DNA replication but not in DNA repair. In addition to the p53-dependent damage response, the stimulation of quiescent cells with serum can also cause a p53-independent elevation in p21 gene expression. It is not clear, however, whether the induction of p21 protein under these two circumstances serves the same purpose. In this study, we have investigated the kinetics of p21 induction by DNA damage and serum stimulation and the consequent effects on cell-cycle progression. Using both normal and repair-deficient human cells, we have also analyzed the nuclear distribution of p21 in relation to that of PCNA.

RESULTS

In vivo immunofluorescence staining experiments indicate that, following UV damage, DNA repair is not inhibited by the presence of a large amount of p21 protein in the nucleus; in contrast, cells undergoing DNA replication during S phase contain very low amounts of p21. The addition of serum induced a transitory elevation of p21 levels, whereas UV damage to cells resulted in a sustained, high level of p21 that was more tightly associated with the nuclear structure. Interestingly, cells deficient in global nucleotide excision-repair displayed a distinct pattern of detergent-insoluble p21 that co-localized with PCNA.

CONCLUSIONS

The in vivo studies presented here, which are consistent with our previous findings in vitro, indicate that p21 has a differential effect on DNA replication and DNA repair, and that the induction of p21 by serum and DNA damage may have different consequences. Furthermore, the co-localization of p21 and PCNA in the nucleus of normal and repair-deficient human cells indicates that p21 and PCNA interact during post-damage events.

[Subcellular localization of blood group substances ABH in human gastrointestinal tracts]

Authers investigated subcellular localization of ABH substances in normal human stomach, duodenum and transverse colon by post-embedding immunogold method using monoclonal antibodies specific for A, B and H antigens. The immunoreactivity was usually restricted to the following organelles: mucigen granules of epithelical cells of gastric mucosa, zymogenic granules of chief cells of the gastric gland, both mucigen granules and Golgi cisternae of neck mucous cells of the gastric gland and of epithelial cells of the duodenum mucosa as well as the Brunner's gland. ABH antigens were also visualized in microvilli of absorptive cells and mucigan granules of goblet cells of the transverse colon. The results suggested that ABH substances in those cells were produced in Golgi cisternae and were transfered to secreting granules, then were secreted with mucus. The mosaic distribution of ABH substances in cells and the effect of embedding resins on ABH antigens and the ultrastructure of cells were discussed.

Lymphoblastoid transmembrane potential in bipolar patients, their siblings, and unrelated healthy comparison subjects

Bipolar illness appears to be characterized by alterations in ionic homeostasis that are related to mood state. This is reflected by reports of altered intracellular sodium and calcium concentrations, altered sodium pump (Na+,K+-adenosine triphosphatase), and calcium pump (Ca2+-adenosine triphosphatase) activity. Recent ex vivo studies with fresh lymphocytes and in vitro studies with cultured lymphoblasts suggest that there may be an enduring trait-related abnormality in Na+,K+-adenosine triphosphatase as well. We have previously found that the lymphocyte transmembrane potential (TMP) varies with mood state. To examine the question of trait-related changes in TMP, we studied TMP of immortalized lymphoblasts from 14 patients with bipolar illness, nine unaffected siblings, and eight normal subjects. TMP was the same in all three groups. These preliminary data suggest that TMP is a state-- rather than a trait-related marker.

Reproducibility of extracranial carotid atherosclerotic lesions assessed by B-mode ultrasound: the Atherosclerosis Risk in Communities Study

The reproducibility in the identification of carotid artery lesions using B-mode ultrasound was studied in a large random sample selected from the Atherosclerosis Risk in Communities (ARIC) Study. Carotid lesions were defined as plaque with or without acoustic shadowing (indicative of mineralization). A weighted kappa (kappa w) statistic was used as a chance-adjusted measure of repeatability. In the ARIC baseline survey, the kappa w values for the assessment of lesions on repeat reading were 0.47, 0.60 and 0.69 in the left common carotid artery, the carotid bifurcation and the internal carotid artery, respectively. In a repeat scanning, the kappa w values ranged from 0.59 to 0.79 in the left carotid segments. The results were similar in the left and right carotid arteries. Covariates (age, race, gender, body mass index, study center) did not influence the reproducibility. Similar results were also found in both the baseline survey and the first follow-up examination. In conclusion, reproducibility in the assessment of carotid lesions by B-mode ultrasound can be achieved in multicenter studies at fair to good levels of agreement.

Amplification, cloning, and sequence comparison of the growth hormone gene for carp (Cyprinus carpio) by the polymerase chain reaction

Total RNA was isolated from carp pituitary gland. The first strand cDNA was synthesized using oligo(dT) 12-18 as a primer, the total RNA as a template, and AMV reverse transcriptase. Next the polymerase chain reaction (PCR) was performed using the first strand cDNA as a template, the synthetic 29 oligonucleotides as primer and Taq DNA polymerase (94 degrees C, 60 s; 55 degrees C, 30 s; 72 degrees C, 50 s; 35 cycles). After PCR amplification, the products were cloned into an E. coli expression vector (PBluescript II KS+/-). The result of the sequence analysis and the restriction map shows that an open reading frame of the carp growth hormone gene contains 630 base pairs which code for a polypeptide of 210 amino acids including 22 amino acids of the signal peptide and 188 amino acids of the nature growth hormone. Nucleotide sequence and amino acid sequence of our carp growth hormone gene are the same as Koren's carp GH cDNA in the coded region. Compared with Chao's carp GH cDNA, the homology of nucleotide sequence and amino acid sequence for our carp growth hormone gene is 95.6% and 96.7%, respectively, in the coded region.

Thyromimetic action of the peroxisome proliferators clofibrate, perfluorooctanoic acid, and acetylsalicylic acid includes changes in mRNA levels for certain genes involved in mitochondrial biogenesis

The effects of three peroxisome proliferators on the mRNA levels for some mitochondrial inner-membrane proteins in rat liver were investigated. Clofibrate, perfluorooctanoic acid, and acetylsalicylic acid all increased the mRNA levels for the mitochondrial-encoded respiratory-chain components cytochrome c oxidase subunit I and NADH dehydrogenase subunit I. Mitochondrial 16S rRNA was also induced by clofibrate. The mRNA levels for the nuclear-encoded mitochondrial inner-membrane proteins adenine nucleotide translocator and cytochrome c1 were selectively induced by the different peroxisome proliferators. Malic enzyme, which is induced by thyroid hormone, was also induced by the three peroxisome proliferators tested. These effects are in some ways similar to those obtained with thyroid hormone.

Effect of domestically-made levonorgestrel-releasing intrauterine device on the endocrine system and menstruation in monkeys

Effect of domestically-made levonorgestrel-releasing intrauterine device (LNG, release rate, 6 micrograms/day) on the endocrine system and menstruation in monkeys was investigated. The results showed that the Estradiol (E2) and progesterone (P) levels were significantly decreased 2 ovulatory cycles after insertion of the devices as compared with those before insertion in 3 monkeys (P > 0.001), suggesting an evident ovulation-suppressing effect. In 1 monkey, the E2 and P levels were the same before and after insertion, and expulsion of device was found in the monkey later. The plasma LNG concentration in 3 animals was 493.69-454.60 pg/ml and plasma LNG was not detected in 1 monkey. The hormone level returned to normal level after removal of the devices.

Hlx homeo box gene is essential for an inductive tissue interaction that drives expansion of embryonic liver and gut

The divergent murine homeo box gene Hlx is expressed in restricted hematopoietic cell types and, during embryogenesis, prominently in visceral mesenchyme of the developing liver, gall bladder, and gut. Targeted disruption of the gene has now established that it plays a key role in visceral organogenesis. Embryos homozygous for the mutation died around embryonic day 15 with anemia and severe hypoplasia of the liver and gut. Liver ontogeny commenced normally with formation of the liver diverticulum and differentiation of hepatocytes, but the organ failed to expand and reached only 3% of normal size. The apparent liver hypoplasia was not associated with a notable increase in apoptotic cells. Gut development also began normally, but the intestines failed to undergo extensive elongation and looping and reached only a quarter of normal length. The anemia resulted from a deficiency in the fetal form of hematopoiesis, which occurs in the liver, but no intrinsic defect in Hlx-/- hematopoietic cells was observed in vitro, and liver-derived Hlx-/- hematopoietic stem cells that were transplanted to irradiated normal mice could fully reconstitute hematopoiesis. The impaired fetal hematopoiesis therefore reflects insufficient support function provided by the minute liver. Hlx is normally expressed in visceral mesenchyme lying adjacent to the developing liver and gut epithelia affected by the mutation, but not in the epithelia themselves. Hence, Hlx regulates a mesenchymal-epithelial interaction that drives a vital growth phase in visceral organogenesis. Moreover, because mutation of Hlx blocked liver growth but not its specification, early morphogenesis, or differentiation, development of this organ appears to occur by step-wise inductive interactions under separate genetic control.

[A study of the immunopathology of Mooren's ulcer]

OBJECTIVE

The study was designed to investigate the immunopathology of bulbar conjunctive adjacent to Mooren's ulcer of the cornea and to evaluate the roles of immune regulation status, the adhesive action of conjunctival cells and leucocytes in the pathological tissue in the pathogenesis of the lesion.

METHOD

15 limbal conjunctival specimens from 14 patients with the progressive Mooren's ulcer were examined by using immunohistochemical stainings for T-lymphocyte and its subsets (Pan-T, TH and TS), B-lymphocyte, intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function associated antigen-1 (LFA-1).

RESULT

The ratio of T-helper to T-suppressor cells (TH/TS) in Mooren's ulcer group was significantly higher than that in the normal group, ICAM-1 was strongly expressed on conjunctival cells, whereas LFA-1 was strongly expressed in infiltrating leukocytes.

CONCLUSION

The immune hyperfunction at the peripheral corneal lesion and its adjacent bulbar conjunctiva possibly is the direct cause of the pathogenesis of Mooren's ulcer. Simultaneously, the mutual action of ICAM-1 and LFA-1 might play an important role in the development of the disease.

In vitro antimalarial activity of chalcones and their derivatives

A series of chalcones and their derivatives have been synthesized and identified as novel potential antimalarials using both molecular modeling and in vitro testing against the intact parasite. A large number of chalcones and their derivatives were prepared using one-step Claisen-Schmidt condensations of aldehydes with methyl ketones. These condensates were screened in vitro against both chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum and shown to be active at concentrations in the nanomolar range. The most active chalcone derivative, 1-(2,5-dichlorophenyl)-3-(4-quinolinyl)-2-propen-1-one (7), had an IC50 value of 200 nM against both a chloroquine-resistant strain (W2) and a chloroquine-sensitive strain (D6). The resistance indexes for all compounds were substantially lower than for chloroquine, suggesting that this series will be active against chloroquine-resistant malaria. Structure-activity relationships (SAR) of the chalcones in the context of a homology-based model structure of the malaria trophozoite cysteine protease, the most likely target enzyme, are presented.

Alternative splicing of amelogenin mRNA from rat incisor ameloblasts

Amelogenin proteins are a major component of the developing enamel matrix, and are likely to have a key role in the control of enamel biomineralization. The heterogeneity of amelogenin is in part due to alternative splicing of the amelogenin RNA transcripts. Several patterns of alternative splicing have been described in mouse, bovine, porcine, and human enamel, with all alternatively spliced products having homologous 5' and 3' sequences within the coding regions. In these studies, we have used anchored PCR to identify alternatively spliced amelogenin cDNA sequences in the rat. We found amelogenin cDNAs that could be divided into two groups based on their 3' sequence. Group 1 cDNAs had a novel terminal sequence that has not been previously identified, while group 2 cDNAs were similar to those previously identified in other animal species. We identified a sequence, identical to the novel 3' amelogenin cDNA sequence, in rat genomic DNA downstream from the previously identified exon 7. The putative amelogenin proteins predicted for the two groups differed in their predicted isoelectric points, with the novel group 1 proteins having a more basic isoelectric point.

The role of neuropeptides in learning and memory: possible mechanisms

Endogenous neuropeptides such as vasopressin, adrenocorticotropin and opioids have significant effects on learning and memory. However, because of the complexity of behaviour, that is defined as 'learning' and 'memory' and, because of the limitation of current knowledge, it has been difficult to interpret these behavioural data, especially via neural mechanisms. The application of modern experimental techniques including molecular biology such as cloning and electrophysiology, such as patch-clamp, has had a significant impact upon the concepts about drugs, including neuropeptides action sites. This allows us to try to interpret some behavioural consequences influenced by neuropeptides. The data on effects of some neuropeptides on behaviours and their possible mechanisms are reviewed. Whatever the mechanisms, vasopressin, adrenocorticotropic hormone and endogenous opioids seem to have important effects upon learning and memory and these open up the possibility that drugs enhance cognitive functions or treat dementia via alteration of functions of neuropeptides. Some criteria are proposed for evaluating the validity of behavioural tests for neuropeptides.

Clinical and serological courses of a newborn with post-transfusion hepatitis C

The clinical and serological course of a haemophilic baby who was transfused with 160 ml of blood containing the hepatitis C virus (HCV) (0.70 Meq. ml-1) on the sixth-post-natal day is described. He is the infant of an HCV-negative mother. One month after the transfusion, there was a marked increase in HCV RNA and a small amount of HCV antibody was detected. This case provides evidence that a newborn is capable of producing HCV antibodies.

Hematopoietic and lung abnormalities in mice with a null mutation of the common beta subunit of the receptors for granulocyte-macrophage colony-stimulating factor and interleukins 3 and 5

Gene targeting was used to create mice with a null mutation of the gene encoding the common beta subunit (beta C) of the granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin 3 (IL-3; multi-CSF), and interleukin 5 (IL-5) receptor complexes (beta C-/- mice). High-affinity binding of GM-CSF was abolished in beta C-/- bone marrow cells, while cells from heterozygous animals (beta C+/- mice) showed an intermediate number of high-affinity receptors. Binding of IL-3 was unaffected, confirming that the IL-3-specific beta chain remained intact. Eosinophil numbers in peripheral blood and bone marrow of beta C-/- animals were reduced, while other hematological parameters were normal. In clonal cultures of beta C-/- bone marrow cells, even high concentrations of GM-CSF and IL-5 failed to stimulate colony formation, but the cells exhibited normal quantitative responsiveness to stimulation by IL-3 and other growth factors. beta C-/- mice exhibited normal development and survived to young adult life, although they developed pulmonary peribronchovascular lymphoid infiltrates and areas resembling alveolar proteinosis. There was no detectable difference in the systemic clearance and distribution of GM-CSF between beta C-/- and wild-type littermates. The data establish that beta C is normally limiting for high-affinity binding of GM-CSF and demonstrate that systemic clearance of GM-CSF is not mediated via such high-affinity receptor complexes.

Intercellular adhesion molecule-2 (CD102) binds to the leukocyte integrin CD11b/CD18 through the A domain

The interactions between the leukocyte-specific beta 2-integrins cluster of differentiation (CD) Ag CD11/CD18 and their ligands, the intercellular adhesion molecules (ICAMs), play important roles in many adhesion-dependent leukocyte functions. ICAM-1 is known to be a ligand for both CD11a/CD18 and CD11b/CD18. ICAM-2, whose two extracellular Ig domains show the highest homology to the two NH2-terminal domains of ICAM-1, has been previously shown to be a ligand for CD11a/CD18. We recently found that a 22-amino acid CD11a/CD18-binding peptide, P1, derived from the first domain of ICAM-2, also binds to purified CD11b/CD18. In the present study, we demonstrate that the ICAM-2 protein interacts with CD11b/CD18, and the binding is through the CD11b A domain.

Intercellular adhesion molecule-2 (CD102) binds to the leukocyte integrin CD11b/CD18 through the A domain

The interactions between the leukocyte-specific beta 2-integrins cluster of differentiation (CD) Ag CD11/CD18 and their ligands, the intercellular adhesion molecules (ICAMs), play important roles in many adhesion-dependent leukocyte functions. ICAM-1 is known to be a ligand for both CD11a/CD18 and CD11b/CD18. ICAM-2, whose two extracellular Ig domains show the highest homology to the two NH2-terminal domains of ICAM-1, has been previously shown to be a ligand for CD11a/CD18. We recently found that a 22-amino acid CD11a/CD18-binding peptide, P1, derived from the first domain of ICAM-2, also binds to purified CD11b/CD18. In the present study, we demonstrate that the ICAM-2 protein interacts with CD11b/CD18, and the binding is through the CD11b A domain.

The three-dimensional structure of NAD(P)H:quinone reductase, a flavoprotein involved in cancer chemoprotection and chemotherapy: mechanism of the two-electron reduction

Quinone reductase [NAD(P)H:(quinone acceptor) oxidoreductase, EC 1.6.99.2], also called DT diaphorase, is a homodimeric FAD-containing enzyme that catalyzes obligatory NAD(P)H-dependent two-electron reductions of quinones and protects cells against the toxic and neoplastic effects of free radicals and reactive oxygen species arising from one-electron reductions. These two-electron reductions participate in the reductive bioactivation of cancer chemotherapeutic agents such as mitomycin C in tumor cells. Thus, surprisingly, the same enzymatic reaction that protects normal cells activates cytotoxic drugs used in cancer chemotherapy. The 2.1-A crystal structure of rat liver quinone reductase reveals that the folding of a portion of each monomer is similar to that of flavodoxin, a bacterial FMN-containing protein. Two additional portions of the polypeptide chains are involved in dimerization and in formation of the two identical catalytic sites to which both monomers contribute. The crystallographic structures of two FAD-containing enzyme complexes (one containing NADP+, the other containing duroquinone) suggest that direct hydride transfers from NAD(P)H to FAD and from FADH2 to the quinone [which occupies the site vacated by NAD(P)H] provide a simple rationale for the obligatory two-electron reductions involving a ping-pong mechanism.

An animal model for mania: preliminary results

1. In human bipolar patients mania and bipolar depression are both characterized by decreased membrane Na,K-AtPase activity. Additionally, digoxin neurotoxicity in patients frequently presents with symptoms of mania or depression. 2. These findings suggest that central nervous system Na,K-ATPase inhibition may play a pathophysiologic role in bipolar illness. 3. The authors tested this hypothesis by administering intracerebroventricular (i.c.v.) ouabain to rats at sublethal doses. The authors then measured behavioral activity as total square crossings in an open field. 4. Motoric activity was significantly increased by i.c.v. administration of 5 microliters of ouabain at 10(-3) M. This preliminary study suggests that i.c.v. ouabain administration may provide a useful animal model of mania that is based on observed biochemical changes in humans.

[Localization of insulin-like growth factor I in the upper end of human fetal femur]

The localization of insulin-like growth factor I in the upper end of the human fetal femur was studied by immunohistochemistry on the undecalcified bone sections. Certain numbers of chondrocytes in germinal, proliferating and hypertrophic zones of the epiphysial growth plates, some osteoblasts and a few osteoclasts were immunoreactive to the antibody to IGF-I. The end-product of the DAB reaction was deposited in the osteoid and bone matrix of metaphysis. Also presented is a discussion on the local effects of IGF-I on the chondrocytes, osteoblasts and osteoclasts.

A spectrophotometric determination of alpha-dicarbonyl compounds and its application to the enzymatic formation of alpha-ketobutyrate

A simple, rapid, and sensitive spectrophotometric method has been developed for the determination of alpha-keto acids, alpha-diketones, and alpha-ketoaldehydes using o-phenylenediamine as a derivatizing reagent in acidic media to yield chromophoric quinoxaline derivatives. Application to the determination of alpha-ketobutyrate and the rate of its formation from isomerization of vinylglycolate catalyzed by mandelate racemase is described. Under optimal conditions 1 to 4 mM o-phenylenediamine in 80% acetic acid was incubated at 50 degrees C for 10 min with the alpha-dicarbonyl compounds. Solutions of alpha-ketobutyrate as low as 5 microM in the buffer solution can be measured quantitatively. This method has also been used for determining the rate of formation of the phenylglyoxalate from (S)-mandelate catalyzed by (S)-mandelate dehydrogenase.

Mice lacking the c-rel proto-oncogene exhibit defects in lymphocyte proliferation, humoral immunity, and interleukin-2 expression

The c-rel proto-oncogene, which is expressed predominantly in hemopoietic cells encodes a subunit of the NF-kappa B-like family of transcription factors. In mice with an inactivated c-rel gene, whereas development of cells from all hemopoietic lineages appeared normal, humoral immunity was impaired and mature B and T cells were found to be unresponsive to most mitogenic stimuli. Phorbol ester and calcium ionophore costimulation, in contrast to certain membrane receptor-mediated signals, overcame the T cell-proliferative defect, demonstrating that T cell proliferation occurs by Rel-dependent and -independent mechanisms. The ability of exogenous interleukin-2 to restore T Cell, but not B cell, proliferation indicates that Rel regulates the expression of different genes in B and T cells that are crucial for cell division and immune function.

Human THP-1 monocyte-macrophage membrane binding proteins: distinct receptor(s) for triglyceride-rich lipoproteins

An apolipoprotein (apo) E- and lipoprotein lipase-independent, high affinity, saturable and specific binding site and pathway for uptake of certain triglyceride-rich lipoproteins (TGRLP) by human monocyte-macrophages that leads to lipid accumulation and foam cell formation in vitro has been reported; two membrane binding activities were identified as receptor candidates with apparent molecular masses of 200 and 235 kDa [Gianturco et al. (1994) J. Lipid Res. 35, 1674-1687]. Here we present new evidence that these activities are TGRLP receptors with unique biochemical properties which distinguish them from other lipoprotein receptors. Protease and heparinase susceptibility studies demonstrate that (1) these activities have essential protein, but not heparan sulfate proteoglycan (HSPG) components; (2) the membrane binding proteins (MBPs) are located on the cell surface; (3) HSPGs do not facilitate TGRLP binding to this specific cellular site. Upon reduction, MBP 200 and 235 are both converted into a single, new binding activity of intermediate mobility (MBP 200R); all MBP forms displayed high affinity, saturable TGRLP binding with similar Kds (1.4-2.2 micrograms/mL). Notably, MBP 200R retained the combined ligand binding capacity of MBP 200 and 235 prior to reduction, demonstrating that, unlike members of the LDL receptor or the scavenger receptor families, disulfide bonds are not critical for activity. At 65 degrees C, MBP 235 was converted into MBP 200 without loss of total binding activity, suggesting heat dissociates a small subunit not required for binding from a common large protein subunit that binds TGRLP. Since the MBPs are found on the cell surface, are themselves functionally and structurally related, have distinctly different biochemical properties from members of the LDL receptor and scavenger receptor families, and share all critical characteristics with the cellular binding site, we hypothesize that they represent a new and unique receptor family for apoE- and lipoprotein lipase-independent uptake of TGRLP by human monocyte-macrophages.

Absence of yolk sac hematopoiesis from mice with a targeted disruption of the scl gene

The scl gene encodes a basic-helix-loop-helix transcription factor which was identified through its involvement in chromosomal translocations in T-cell leukemia. To elucidate its physiological role, scl was targeted in embryonic stem cells. Mice heterozygous for the scl null mutation were intercrossed and their offspring were genotyped. Homozygous mutant (scl-/-) pups were not detected in newborn litters, and analysis at earlier time points demonstrated that scl-/- embryos were dying around embryonic day 9.5. The scl-/- embryos were pale, edematous, and markedly growth retarded after embryonic day 8.75. Histological studies showed complete absence of recognizable hematopoiesis in the yolk sac of these embryos. Early organogenesis appeared to be otherwise normal. Culture of yolk sac cells of wild-type, heterozygous, and homozygous littermates confirmed the absence of hematopoietic cells in scl-/- yolk sacs. Reverse transcription PCR was used to examine the transcripts of several genes implicated in early hematopoiesis. Transcripts of GATA-1 and PU.1 transcription factors were absent from RNA from scl-/- yolk sacs and embryos. These results implicate scl as a crucial regulator of early hematopoiesis.

Myogenic and morphogenetic defects in the heart tubes of murine embryos lacking the homeo box gene Nkx2-5

The murine homeo box gene Nkx2-5 is expressed in precardiac mesoderm and in the myocardium of embryonic and fetal hearts. Targeted interruption of Nkx2-5 resulted in abnormal heart morphogenesis, growth retardation and embryonic lethality at approximately 9-10 days postcoitum (p.c.). Heart tube formation occurred normally in mutant embryos, but looping morphogenesis, a critical determinant of heart form, was not initiated at the linear heart tube stage (8.25-8.5 days p.c.). Commitment to the cardiac muscle lineage, expression of most myofilament genes and myofibrillogenesis were not compromised. However, the myosin light-chain 2V gene (MLC2V) was not expressed in mutant hearts nor in mutant ES cell-derived cardiocytes. MLC2V expression normally occurs only in ventricular cells and is the earliest known molecular marker of ventricular differentiation. The regional expression in mutant hearts of two other ventricular markers, myosin heavy-chain beta and cyclin D2, indicated that not all ventricle-specific gene expression is dependent on Nkx2-5. The data demonstrate that Nkx2-5 is essential for normal heart morphogenesis, myogenesis, and function. Furthermore, this gene is a component of a genetic pathway required for myogenic specialization of the ventricles.

Tb3+ binding to human erythrocyte spectrin resulting in conformation change and aggregation

The Tb3+ binding to spectrin tetramer (SPT) was studied by Tb3+ fluorescence titration and CD spectra. The results indicated that the total high-affinity Tb3+ binding sites are n1 = 330, with average Kd = 3.6 x 10(-6) M. Among them, ca. 90 sites are of higher affinity and are probably more specific to Tb3+ than the remaining sites. There are 520 low affinity Tb3+ binding sites with average Kd = 1.5 x 10(-5) M. Fluorescence and CD spectra revealed that the alpha-helix content of SPT decreased with Tb3+ binding to specific sites and further binding did not result in conformation change. Tb3+ binding to SPT and the subsequent reactions were studied by employing stopped-flow fluorescence and light scattering methods. The studies demonstrate that this is a multistep reaction assembly: high-affinity terbium binding-conformation change-aggregation-low-affinity terbium binding--the second conformation change. The critical Tb3+ concentration-induced spectrin dimer (SPD) aggregation was determined with a light scattering method.

[Dumbbell like neurinoma at upper cervical vertebra: report of 48 cases]

48 dumbbell like neurinoma at upper cervical vertebra were totally removed operatively and confirmed pathologically. Intermittent pain at neck and occiput limitation of neck movement, and numbness or pain at one or both side limbs were the most common symptoms. In the early stage, the disease was difficalt to recognize. If X-ray film of the cervical vertebra at bioblique position showed an enlarged intervertebral foramen, the diagnosis of neurinoma should be highly considered. MRI could make a definite diagnosis. Vertebral artery angiography is of great value. We also introduced experience in how to protect vertebral artery and respiratory function during operation.

The role of thyroid hormone and promoter diversity in the regulation of nuclear encoded mitochondrial proteins

Thyroid hormone regulates the in vivo expression of a selected set of rat nuclear genes encoding mitochondrial inner membrane proteins. Certain mRNAs, such as that for cytochrome c1, are increased as much as 20-50-fold, while others, such as core protein 1 of Complex III and the F1-ATPase beta-subunit do not respond. The promoter region of human cytochrome c1 also supports thyroid hormone induction of a reporter gene in transient transfection experiments. Thus, thyroid hormone regulates only selected genes, even for subunits within the same complex and in widely varying species. By contrast, growth activation of quiescent NIH3T3 cells, a second paradigm used for stimulating mitochondrial biogenesis, does not increase cytochrome c1 mRNA but does increase F1-ATPase beta-subunit mRNA. These findings suggest that nuclear OXPHOS genes are not necessarily expressed in a coordinated manner, and that multiple regulatory circuits might exist which are linked to different physiological stimuli. Analysis of the promoters of several OXPHOS genes reveals a great diversity and heterogeneity of transfactor binding elements. No single regulatory feature exists which could account for a coordinated expression of all OXPHOS genes. The potential diversity for regulating expression of nuclear OXPHOS genes raises the possibility for the existence of disease states linked to regulatory defects.

Purification of the human THP-1 monocyte-macrophage triglyceride-rich lipoprotein receptor

Previously we reported that human blood-borne and THP-1 monocyte-macrophages have an apolipoprotein E- and lipoprotein lipase-independent, high affinity, specific binding site for the uptake and degradation of hypertriglyceridemic VLDL and plasma chylomicrons distinct from the LDL receptor gene family and the acetyl LDL receptor (Gianturco et al., J. Lipid Res. 35:1674-1687, 1994). Ligand blot analyses identified two cell-surface, structurally related membrane binding proteins as receptor candidates of M(r) approximately 200 kDa and M(r) approximately 235 kDa which are converted into a single ligand binding species of intermediate mobility upon reduction. We now report a approximately 1200-fold purification of the reduced candidate receptor protein from cultured THP-1 monocytes.

A peptide derived from the intercellular adhesion molecule-2 regulates the avidity of the leukocyte integrins CD11b/CD18 and CD11c/CD18

beta 2 integrin (CD11a,b,c/CD18)-mediated cell adhesion is required for many leukocyte functions. Under normal circumstances, the integrins are nonadhesive, and become adhesive for their cell surface ligands, the intercellular adhesion molecules (ICAMs), or soluble ligands such as fibrinogen and iC3b, when leukocytes are activated. Recently, we defined a peptide derived from ICAM-2, which specifically binds to purified CD11a/CD18. Furthermore, this peptide strongly induces T cell aggregation mainly mediated by CD11a/CD18-ICAM-1 interaction, and natural killer cell cytotoxicity. In the present study, we show that the same ICAM-2 peptide also avidly binds to purified CD11b/CD18, but not to CD11c/CD18. This binding can be blocked by the CD11b antibody OKM10. The peptide strongly stimulates CD11b/CD18-ICAM-1-mediated cell aggregations of the monocytic cell lines THP-1 and U937. The aggregations are energy and divalent cation-dependent. The ICAM-2 peptide also induces CD11b/CD18 and CD11c/CD18-mediated binding of THP-1 cells to fibrinogen and iC3b coated on plastic. These findings indicate that in addition to induction of CD11a/CD18-mediated cell adhesion, the ICAM-2 peptide may also serve as a "trigger" for high avidity ligand binding of other beta 2 integrins.

Molecular geometries of dibenzothiazepinone and dibenzoxazepinone calcium antagonists

A number of dibenzothiazepinones and dibenzoxazepinones have been designed, synthesized and evaluated as calcium antagonists. Molecular geometries of these dibenzotricyclic calcium antagonists have been studied using X-ray crystallography, molecular modeling and two-dimensional NMR spectroscopy. X-Ray diffraction reveals dibenzothiazepinone 1 and dibenzoxazepinone 2 to have, respectively, flexure angles of 108 degrees and 116.9 degrees between the two benzene rings. The molecular mechanics-optimized geometry of dibenzothiazepinone 1 shows a 7 degrees smaller flexure angle than the X-ray crystallographic result, while that of dibenzoxazepinone 2 has an angle only 2 degrees smaller than the X-ray result. AM1 and ab initio calculations show that the side chains can affect the geometry of the tricyclic nucleus and both 1 and 2 have negative electrostatic potentials around the bridged portion of the tricyclics. Two-dimensional NOESY NMR spectroscopy supports the extended geometry of the 6 carbon spacer as obtained from X-ray crystallography and molecular mechanics calculations. Vasorelaxation properties among these compounds appear to be relatively insensitive to the flexure angle and to chain length. Vasorelaxation is profoundly influenced by the nature of the basic terminal moiety.

[Changes of ABH substances amount in human tissues after treatment with physico-chemical factors]

The forensic samples for identify testing are always affected by the environmental or the physico-chemical influence. The aim of the present study is to study whether the physico-chemical or biological factors affect the quantity of ABH substances in human tissues or not. The quantity of the ABH substances was determined by immunohistochemical ABC method. The tissues were treated by a series of methods, including immersing in water, treatment with heat, acid, alkali as well as putrefaction and mold growing. The results revealed that although the ABH substances slightly decreased in some tissues pretreated, no effect of ABO typing was observed. The correct ABO typing was performed with tissues under the following condition: the tongue and skin immersed in water for 21 days; the tongue treated with heat (100 degrees C) for 40 min; the tongue and skin treated with 0.2mol/L HCl and 0.2 mol/L NaOH for 48 h and the skin treated with 12mol/L HCl and 12mol/L NaOH for 30 min. The ABO typing of pancreas undergoing putrefaction and mold growing 21 days was carried out correctly. It is concluded that the ABC immunohistochemical technique is a good method for ABO typing of human tissues.

Activin promotes ovarian follicle development in vitro

Activin is a protein originally isolated from follicular fluid as a factor stimulating FSH release from the pituitary. The present experiments support the hypothesis that activins may also regulate follicle development by autocrine/paracrine mechanisms. Granulosa-oocyte complexes were isolated by collagenase/dispase dispersion of ovaries from 14- or 21-day-old rats and cultured in serum-free medium. Within 24 h, the cells had spread to form a monolayer. Hormones and growth factors were added at this time. Cell number and thymidine incorporation were measured after an additional 72 h. In the presence of insulin and transferrin, activin-A increased both granulosa cell number and thymidine incorporation more than 2-fold. This effect could be inhibited by follistatin, an activin-binding protein. In addition, activin-A, in the presence of FSH, induced reorganization of follicular structures from monolayer culture of cells from 14-day-old rats and caused cells from primary follicles to develop into large follicle-like structures. These structures contained oocytes, a cumulus layer, an antrum, and a multilayered follicular wall with a diameter of more than 1 mm. Electron microscopy revealed that the cells in the follicle-like structure were connected by gap junctions. Oocytes showed a mature morphology and had closely associated cumulus layers. Dissociation of the follicular wall in these follicle-like structures was induced by the addition of LH, resembling the induction of ovulation in vivo. The findings are important for understanding follicular development and atresia.

Relation of activity levels to body fat in infants 6 to 12 months of age

We examined longitudinally the relation between body fatness and physical activity, adjusting for energy intake, in 31 healthy white infants. Measures of physical activity, dietary intake, and body composition were obtained at 6, 9, and 12 months of age. The percentage of body fat was inversely related to activity level, an association that became stronger with increasing age and remained significant after adjustment for dietary energy intake. The percentage of body fat was not related to energy consumed per lean body mass regardless of high or low activity level, nor was energy consumed related to physical activity. We conclude that the percentage of body fat in infants may be related more to their activity levels than to their energy intake.

Regulation of cortical actin cytoskeleton assembly during polarized cell growth in budding yeast

We have established an in vitro assay for assembly of the cortical actin cytoskeleton of budding yeast cells. After permeabilization of yeast by a novel procedure designed to maintain the spatial organization of cellular constituents, exogenously added fluorescently labeled actin monomers assemble into distinct structures in a pattern that is similar to the cortical actin distribution in vivo. Actin assembly in the bud of small-budded cells requires a nucleation activity provided by protein factors that appear to be distinct from the barbed ends of endogenous actin filaments. This nucleation activity is lost in cells that lack either Sla1 or Sla2, proteins previously implicated in cortical actin cytoskeleton function, suggesting a possible role for these proteins in the nucleation reaction. The rate and the extent of actin assembly in the bud are increased in permeabilized delta cap2 cells, providing evidence that capping protein regulates the ability of the barbed ends of actin filaments to grow in yeast cells. Actin incorporation in the bud can be stimulated by treating the permeabilized cells with GTP-gamma S, and, significantly, the stimulatory effect is eliminated by a mutation in CDC42, a gene that encodes a Rho-like GTP-binding protein required for bud formation. Furthermore, the lack of actin nucleation activity in the cdc42 mutant can be complemented in vitro by a constitutively active Cdc42 protein. These results suggest that Cdc42 is closely involved in regulating actin assembly during polarized cell growth.

Specific binding of Synechococcus sp. strain PCC 7942 proteins to the enhancer element of psbAII required for high-light-induced expression

The psbAII gene of the cyanobacterium Synechococcus sp. strain PCC 7942 is a member of a three-gene family that encodes the D1 protein of the photosystem II reaction center. Transcription of psbAII is rapidly induced when the light intensity reaching the culture increases from 125 microE.m-2.s-1 (low light) to 750 microE.m-2.s-1 (high light). The DNA segment upstream of psbAII that corresponds to the untranslated leader of its major transcript has enhancer activity and confers high-light induction. We show that one or more soluble proteins from PCC 7942 specifically bind to this region of psbAII (designated the enhancer element). In vivo footprinting showed protein binding to the enhancer element in high-light-exposed cell samples but not in those maintained at low light, even though in vitro mobility shifts were detectable with extracts from low- or high-light-grown cells. When 12 bp were deleted from the psbAII enhancer element, protein binding was impaired and high-light induction of both transcriptional and translational psbAII-lacZ reporters was significantly reduced. This finding indicates that protein binding to this region is required for high-light induction of psbAII. The mutant element also showed impaired enhancer activity when combined with a heterologous promoter.

Morphology and morphogenesis of hepatitis E virus (strain 87A)

The morphology and morphogenesis of isolated hepatitis E virus (HEV, strain 87A) were observed by electron microscopy (EM) and immune electron microscopy (IEM). Progressively developing local vesicles, virions accumulation in crystalline arrays and viroplasmic focus were seen in cytoplasm of infected cells. Replication and assembly of the new generation viruses were closely associated with rough endoplasmic reticulum (RER), inclusion body (IB) and microfibrils. Condensation and margination of chromatin, dispersion of nucleolar material, nuclear membrane alteration and masses of threads, granular material, and fibrillar component of the nucleus were frequently found. These changes revealed that this strain virus was confirmed as a RNA virus. The shape of the virus particles appeared approximately spherical whether the specimens were from the tissue culture crude suspension or purified highly concentrated preparations. The size of the virion was about 30 nm in diameter. The viral particles appeared unsmooth and irregular in outline. The spike-like structures may be occasionally observed on the surface of some viral capsides. The diameter of the strain 87 A virus is larger than the picornavirus and smaller than the calicivirus. This strain virus is different from classical calicivirus in without the cup-shaped surface depressions. The new genus, heparnavirus genus of caliciviridae family should be proposed for HEV.