Myeloma Ig heavy chain V region sequences reveal prior antigenic selection and marked somatic mutation but no intraclonal diversity

The lg VH region sequence in 48 patients with multiple myeloma (MM) was analyzed to characterize the malignant cell of origin. The sequences were obtained after amplification of bone marrow cDNA by using VH family-specific and CH primers, then compared with either directly sequenced patient germ-line or published VH gen sequences to assay for somatic mutation. Because somatic hypermutation of the VH gene occurs late in B cell development, its presence has been helpful in determining the cell of origin in other B cell malignancies. Overall, a median of 8.2% of the nucleotides had evidence of substitution within each VH gene sequence (range=2.7% to 16.5%), which is more prevalent than in any other reported tumor type. Strong evidence of prior antigenic selection pressure was also evident. The ratio of nucleotide substitutions that resulted in amino acid replacement was significantly higher in the complementarity-determining region than in the framework region (3.25 vs 1.56, respectively; p < 0.00005). No VH gene intraclonal diversity was noted, despite sequencing multiple clones (3-16) from each patient, nor was there evidence of further VH gene somatic mutation over the course of three patients' disease. These findings strongly imply that the malignant clone in MM evolves from a cell late in B cell development.

Characterization of a cAMP-binding protein from the bivalve mollusc Mytilus galloprovincialis

Three cAMP-binding proteins have been identified by photoaffinity labeling with 8-azido[32P]cAMP and purified from the mantle tissue of the sea mussel Mytilus galloprovincialis. Their molecular masses, determined by SDS/PAGE, were 54, 42 and 37 kDa. The purified 54-kDa protein, which had two cAMP-binding sites/monomer, was judged to be a regulatory (R) subunit of cAMP-dependent protein kinase since it re-associated with and inhibited purified catalytic (C) subunit of this enzyme from mussel, in the absence but not in the presence of cAMP. The molecular mass of the complex between Mytilus cAMP-binding protein and C subunit, estimated by analytical gel-filtration, was 220 kDa, a value which agrees with a R2C2 stoichiometry for the mussel cAMP-dependent protein kinase holoenzyme. On the basis of the elution pattern from DEAE-cellulose chromatography and its ability to be phosphorylated by purified C subunit of cAMP-dependent protein kinase, the 54-kDa protein could be classified as a type II regulatory subunit. Furthermore, no mobility shift on SDS/PAGE upon phosphorylation/dephosphorylation of Mytilus protein was observed, a similar behaviour to that shown by the mammalian RII beta isoform. The 42-kDa and 37-kDa proteins, which were recognized by a specific antiserum against the 54-kDa protein and fail to be phosphorylated by Mytilus C subunit, are probably products generated by proteolysis of the 54-kDa protein, although they were shown even when inhibitors of the major types of proteases were used.

Myeloma Ig heavy chain V region sequences reveal prior antigenic selection and marked somatic mutation but no intraclonal diversity

The lg VH region sequence in 48 patients with multiple myeloma (MM) was analyzed to characterize the malignant cell of origin. The sequences were obtained after amplification of bone marrow cDNA by using VH family-specific and CH primers, then compared with either directly sequenced patient germ-line or published VH gen sequences to assay for somatic mutation. Because somatic hypermutation of the VH gene occurs late in B cell development, its presence has been helpful in determining the cell of origin in other B cell malignancies. Overall, a median of 8.2% of the nucleotides had evidence of substitution within each VH gene sequence (range=2.7% to 16.5%), which is more prevalent than in any other reported tumor type. Strong evidence of prior antigenic selection pressure was also evident. The ratio of nucleotide substitutions that resulted in amino acid replacement was significantly higher in the complementarity-determining region than in the framework region (3.25 vs 1.56, respectively; p &lt; 0.00005). No VH gene intraclonal diversity was noted, despite sequencing multiple clones (3-16) from each patient, nor was there evidence of further VH gene somatic mutation over the course of three patients' disease. These findings strongly imply that the malignant clone in MM evolves from a cell late in B cell development.

[A preliminary report of small incision cataract surgery by phacoemulsification]

The results of 34 cases with cataract extracted by phacoemulsification were preliminarily reported. Postoperatively, they achieved corrected visual acuities > 1.0 in 24 eyes (70.59%) in one week and in 25 eyes (73.53%) after 3 months. The post-operative astigmatism showed a tendency of change from with-the-rule shifting to against-the-rule. The rate of the corneal endothelial cell loss was 13.28%. No severe intra- and post-operative complications were found. It is concluded that the small incision, slight post-operative reaction and fast visual rehabilitation inherent in phacoemulsification procedures are more beneficial to patients than the conventional extracapsular cataract extraction.

Comparative trace mineral nutritional balance of first-litter gilts under two dietary levels of copper intake

Seven pairs of purebred Landrace first-litter gilts, housed in individual stainless-steel metabolic cages were used in this study. A low-Cu (LCu) basal diet containing only 2 mg/kg of Cu was compared to the control (CCu) diet, which was supplemented with cupric carbonate to provide 10 mg/kg of Cu. Both diets were fed at the rate of 2 kg per day to first-litter gilts during the entire pregnancy. The metabolic response under these two levels of dietary Cu intake was evaluated through nutritional balances conducted for 5 days starting at 30, 60 and 100 days of pregnancy. Total urine collection was done through teflon-coated catheters to the bladder while daily fecal collection was carried out continuously. Water consumption was measured and periodic samples were collected for analysis. Nutritional balances included DM digestibility, Cu, Zn, Fe and Mn. The LCh group consumed 4.26 mg of Cu per day while the CCu received 25 mg of Cu per day. This includes 1 mg per day in the drinking water in both groups. DM digestibility was significantly (P < 0.05) higher during early pregnancy in the LCu group compared to the CCu group, which showed a significant (P < 0.05) increase in DM digestibility from early to late pregnancy period. Dietary Cu intake had a direct effect (p < 0.05) on Cu balance but also altered the Zn and Fe nutritional balance, leaving Mn balance almost unchanged. Feces represented the almost exclusive route of excretion of trace minerals. Regardless of the dietary Cu intake, it represents more than 99.9% of the Fe and Mn, 98% of the Zn and 97% of the Cu was excreted daily through feces plus urine. The nutritional balance of Cu, Zn and Fe, in absolute amounts as well as relative to the level of intake, improved significantly as pregnancy progressed. Although relative retention of the low-Cu group was significantly improved compared to the control group, the absolute amount was still much lower. The well recognized dietary and metabolic interactions of Cu with Zn and Fe were evident in the first-litter gilts receiving the low-Cu diet during pregnancy. The absolute amount, as well as the relative retention as a % of the intake, was increased on average during the entire pregnancy for Zn by more than 70% and for Fe by more than 80% during the last third of pregnancy. In contrast Mn balance was almost unchanged. The major response to low-Cu intake was directed toward greater apparent absorption of the trace minerals which was reflected in a reduced fecal excretion.

Transplantation of CD34+ peripheral blood progenitor cells after high-dose chemotherapy for patients with advanced multiple myeloma

A major potential problem of autologous transplantation in the treatment of advanced malignancy is the infusion of tumor cells. A multi-institutional study of purified CD34-selected peripheral blood progenitor cell (PBPC) transplantation was conducted in 37 patients with advanced multiple myeloma receiving myeloablative chemotherapy. Fourteen days after intermediate-dose cyclophosphamide, prednisone, and granulocyte colony-stimulating factor (G-CSF), a median of 3 (range, 2 to 5) 10-L leukaphereses yielded 9.8 x 10(8)/kg (range, 3.7 to 28.3) mononuclear cells. The adsorbed (column-bound) fraction contained 5.9 x 10(6) cells/kg (range, 1.6 to 25.5) with 4.65 x 10(6) CD34 cells/kg (range, 1.2 to 23.3). Using Poisson distribution analysis of positive polymerase chain reactions with patient-specific complementarity-determining region 1 (CDR1) and CDR3 Ig-gene primers, tumor was detected in leukapheresis products from 8 to 14 unselected patients and ranged from 1.13 x 10(4) to 2.14 x 10(6) malignant cells/kg. After CD34 selection, residual tumor was detected in only three patients' products. Overall, a greater than 2.7- to 4.5-log reduction in contaminating multiple myeloma cells was achieved. CD34 PBPCs were infused 1 day after busulfan (14 mg/kg) and cyclophosphamide (120 mg/kg), and granulocyte-macrophage colony-stimulating factor was used until hematologic recovery. The median time to both neutrophil and platelet recovery was 12 days (range, 11 to 16 days and 9 to 52 days, respectively). The median number of erythrocyte and platelet transfusions was 7 (range, 2 to 37) and 3 (range, 0 to 85), respectively. Patients receiving fewer than 2 x 10(6) CD34 cells/kg had significantly prolonged neutropenia, thrombocytopenia, and an increased red blood cell and platelet transfusion requirement. Thus, CD34 selection of PBPCs markedly reduces tumor contamination in multiple myeloma and provides effective hematopoietic support for patients receiving myeloablative therapy.

Ordered translocation of 987P fimbrial subunits through the outer membrane of Escherichia coli

The 987P fimbria of enterotoxigenic Escherichia coli is a heteropolymeric structure which consists essentially of a major FasA subunit and a minor subunit, the FasG adhesin. The latter harbors the binding moiety for receptor molecules on piglet intestinal epithelial cells. In this study, anti-FasF antibody probes were developed and used to demonstrate that the FasF protein represents a new minor fimbrial component. FasF was identified in highly purified fimbriae, and its sequence demonstrated significant levels of similarity with that of FasA. Immune electron microscopy localized both the FasG and FasF proteins at the fimbrial tip as well as at broken ends and at various intervals along the fimbrial length. The presence of these minor proteins in purified 987P fimbriae was corroborated by enzyme-linked immunosorbent assay inhibitions. Finally, the use of nonfimbriated fasG, fasF, and fasA mutants indicated that subunit translocation through the outer membrane follows a specific order, FasG being the first, FasF being the second, and FasA being the third type of exported subunit. Since fimbriae are thought to grow from the base, FasG is proposed to be a tip adhesin and FasF is proposed to be a linker molecule between the adhesin and the fimbrial shaft. Moreover, export of FasG (or FasF) in the absence of FasF (or FasA) indicates that during the process of fimbrial biogenesis in the outer membrane, translocating events precede the initiation of subunit heteropolymerization.

Cellular sterol accumulation stimulated by cholesterol 5 beta,6 beta-epoxide in J774 macrophages

A significant accumulation of cellular free cholesterol and steryl esters is observed in J774 macrophages when cells are exposed to low-density lipoproteins (LDL) containing cholesterol 5 beta,6 beta-epoxide. This cellular sterol accumulation is mainly due to the formation of esterified cholesterol and desmosterol. Cellular steryl esters increased to 39.4 and 22.4 micrograms/mg cell protein with 0.8 microM of cholesterol 5 beta,6 beta-epoxide and 3,5-cholestadien-7-one, respectively, whereas hardly detectable levels were observed with the absence of oxysterols. The total cellular sterols increased 45% above the value of control with cholesterol 5 beta,6 beta-epoxide. The uptake of [3H] cholesteryl oleate-LDL was also enhanced by cholesterol 5 beta,6 beta-epoxide. The rapid displacement of desmosterol with cholesterol was observed when cells were treated with cholesterol 5 beta,6 beta-epoxide or 3,5-cholestadien-7-one in the presence of LDL. Cholesterol 5 beta,6 beta-epoxide became associated with LDL in the culture conditions, and its uptake into J774 cells and the cytotoxicity were reduced significantly by the association with LDL. The comparison of selected oxysterols for their ability to stimulate cellular sterol accumulation indicated that cholesterol 5 beta,6 beta-epoxide is the most potent. Cholesterol esterification was enhanced significantly by cholesterol 5 beta,6 beta-epoxide whereas cholesterol 5 alpha,6 alpha-epoxide and 3,5-cholestadien-7-one produced a modest response. In contrast, although cholestantriol, the metabolic hydrolysis product of cholesterol epoxides, also associated with LDL, it showed no stimulating effect on both cellular sterol content and sterol esterification. These results indicate that some oxysterols, such as cholesterol 5 beta,6 beta-epoxide and possibly 3,5-cholestadien-7-one, stimulate cellular sterol accumulation in J774 macrophages and may play an important role in atherogenesis.

[Management of Labbé's vein in subtemporal operation]

Management of Labbé's vein in operations of cerebellar pons angle (CPA) and clivus regions was reported. Ligation of the Labbé's vein in the left side resulted in hematoma in the temporal lobe or aphasia. In preservation of Labbé's vein, either on the left or right side, only one case of intracerebral hematoma occurred. The reason for this difference was discussed. In protecting Labbé's vein, continuous ventricular draining and removal of the inferior temporal gyrus if necessary was effective.

Identification of malignant cells in multiple myeloma bone marrow with immunoglobulin VH gene probes by fluorescent in situ hybridization and flow cytometry

Because it has been difficult to identify and separate malignant cells in human lymphoid malignancies, we have developed a flow cytometry-based fluorescent in situ hybridization (FISH) technique using immunoglobulin (Ig) heavy chain variable region (VH) gene probes. After obtaining the specific VH gene sequence expressed by the multiple myeloma IM-9 cell line and the malignant cells in five multiple myeloma patients, sense and antisense biotinylated single-stranded RNA probes were prepared by transcription from the malignant clone's VH DNA sequences. The cells from the IM-9 cell line and from the mononuclear bone marrow cells of multiple myeloma patients were fixed, hybridized with the above biotinylated RNA probes, incubated with streptavidin-phycoerythrin, and analyzed by FACS analysis. The myeloma cells stained positive with their own specific antisense VH biotinylated RNa probes, whereas sense and irrelevant antisense biotinylated probes demonstrated only background staining. Dilutional concentrations of the IM-9 cell line with normal bone marrow cells were also accurately quantitated by this procedure. The application of this technique will allow a more accurate assessment of tumor burden in patients with multiple myeloma and should permit an accurate method of tumor cell purification for clinical as well as biological studies. Furthermore, this technological advance should be equally effective at identifying specific VH gene-expressing cells in other lymphoid malignancies, as well as in nonmalignant B cell disorders.

[Onco-gene c-fos expression in light-damaged human embryo retinal pigment epithelium and protective effect of taurine and gamma-interferon]

We used well-cultured human embryo retinal pigment epithelial (RPE) cells to establish a light-damaged RPE cell model. There was no onco-gene c-fos expression in RPE cells cultured under normal condition. Immediately after 30 minutes of light exposure, onco-gene c-fos expression occurred in the RPE cells. The expression reached the highest level 1.5 hours after light exposure and disappeared 4 hours later. Taurine and gamma-interferon in different concentrations could restrain onco-gene c-fos expression in light damaged RPE cells. The restraint effects were of concentration dependence.

[Significance and detection of insulin-like growth factor I in vitreous with proliferative retinal diseases by radioimmunoassay]

The insulin-like growth factor I (IGF-I) levels in 67 vitreous samples taken from 57 patients with various proliferative retinal diseases and 10 normal subjects were detected by radioimmunoassay (RIA). The acid-ethanol-extracted (AEE) method was used to remove the IFG-binding protein before the detection. Our results revealed that IGF-I levels were increased to varying extents in these patients' vitreous. The IGF-I levels in the vitreous with proliferative diabetic retinopathy (PDR) and central retinal vein occlusion (CRVO) were significantly higher than those of the controls. In the PDR group, the increased IGF-I level in the vitreous was positively correlated with the level in serum. The increased IGF-I level in vitreous may play an important role in the development and pathogenesis of proliferative retinal diseases. Great differences were found between the native and the AEE treated vitreous, suggesting that the binding protein posed an obvious interference on the detection of IGF-I by RIA.

The effects of low dietary copper intake during pregnancy on physiological fluids and reproductive performance of first-litter gilts

Seven pairs of first littermate gilts were used to study the influence of low copper supply and pregnancy on physiological fluids and reproductive performance of first-litter gilts. They were fed semi-purified diets containing either 2.13 or 12.25 micrograms/kg of Cu from 30 days of gestation through two weeks of lactation. Low-Cu gilts had lower plasma Cu in early- and mid- gestation and farrowed piglets with lower plasma Cu and higher plasma Zn concentrations (p < 0.05). Plasma Fe and Mn concentrations were not affected by Cu supply (p > 0.05). Plasma Cu and Fe levels of newborn piglets were lower than those of their dams (p < 0.05) but this was not true for plasma Zn and Mn (p > 0.05). Low-Cu gilts had lower Cu and higher Zn content in colostrum and also lower Cu in milk than control gilts (p < 0.05). No significant differences were found in Fe and Mn levels in colostrum and milk between the two treatments (p > 0.05). Colostrum was richer in Cu and Zn than milk (p < 0.05) but not in Fe and Mn (p > 0.05). The low-Cu diet did not affect (p > 0.05) weight changes during pregnancy. The duration of parturition was shorter for low-Cu than for control gilts (3.19h vs. 5.71h, p < 0.05). Control gilts farrowed larger litters than low-Cu gilts (9.71 vs. 7.57 piglets, p < 0.05). There were no significant differences in live litter weights at birth, one wk. or two wks. of age (p > 0.05). The results indicated that a low-Cu diet and pregnancy had some effect on plasma, colostrum and milk mineral concentrations, as well as on litter size of gilts. An interaction between Cu and Zn was found.

Translational inhibition by a human cytomegalovirus upstream open reading frame despite inefficient utilization of its AUG codon

The second of three short upstream open reading frames (uORF2) in the transcript leader of the human cytomegalovirus gp48 (gpUL4) virion glycoprotein gene inhibits downstream translation approximately 10-fold. Remarkably, this inhibition depends on the amino acid coding information of uORF2. In the current studies we demonstrate that expression of the cistron downstream from uORF2 depends on ribosomes bypassing the uORF2 AUG codon (AUG2) by a leaky scanning mechanism. Replacing the nucleotides surrounding the wild-type AUG2 codon with those optimal for translation initiation reduces downstream translation approximately 10-fold. Analyses of mutants in which uORF2 either overlaps or is in frame with the downstream reading frame reveal that the initiation frequency at the wild-type AUG2 codon is surprisingly low; rather, the majority of ribosomal subunits bypass the wild-type AUG2 codon because of its suboptimal context. We propose a model to explain this unprecedented example of a paradoxically strong inhibitory effect of an upstream ORF despite inefficient utilization of its initiation codon.

The C-terminal region of membrane type matrix metalloproteinase is a functional transmembrane domain required for pro-gelatinase A activation

We identified a new matrix metalloproteinase (membrane type matrix metalloproteinase (MT-MMP)) that has a potential transmembrane (TM) domain at the C terminus and reported its expression on the surface of invasive tumor cells. The expression of MT-MMP induced specific activation of 72-kDa pro-gelatinase A (Sato, H., Takino, T., Okada, Y., Cao, J., Shinagawa, A., Yamamoto, E., and Seiki, M. (1994) Nature 370, 61-65). Thus, MT-MMP on the cell surface is thought to play an important role in various physiological and pathological processes accompanying tissue remodeling. In this study, we demonstrated that the potential TM domain deduced from the amino acid sequence functions as a membrane linker when it is fused to a secretory protein, tissue inhibitor of matrix metalloproteinases-1. The pro-gelatinase A activation function of MT-MMP was abolished by truncation of the TM domain and recovered by fusing the MT-MMP mutant with the TM domain of interleukin 2 receptor alpha-chain. The truncated MT-MMP was released from the cells into the medium and detected as processed or modified forms. In spite of the deletion of the TM domain some portions of the mutant MT-MMP were still retained on the surface of cells. Thus, MT-MMP has an additional device to keep it on the cell surface. The TM domain however, plays an essential role in the pro-gelatinase A activation function of MT-MMP, probably regulating its fine orientation or the localization that is necessary to interact with substrate.

Multiple myeloma clones are derived from a cell late in B lymphoid development

We have previously demonstrated that the immunoglobulin (Ig) heavy chain variable region (VH) sequences expressed by the malignant clone in multiple myeloma (MM) contain a high degree of somatic mutation without clonal diversity. This sequence can be used to identify all members of the malignant clone in this B cell malignancy. We sequenced the variable regions expressed by patients with MM and generated primers from the complementarity determining region (CDR) sequences specific for each patient's tumor. Using these primers, we performed PCR amplification on highly purified subpopulations of cells separated by expression of CD10, CD34 and CD38. The results of these experiments demonstrate: 1) there is a small fraction of CD10-expressing tumor cells in MM patients, 2) CD34-bearing malignant cells do not exist in MM, and 3) although the vast amount of tumor is in the CD38-expressing cells, a small amount of tumor is in the CD38-negative population. We also used these primers to determine whether pre-class switch (i.e., Cmu-expressing lymphocytes) clonal cells exist in these patients. After PCR amplification with CDR1 and Cmu primers, colony hybridization was performed using both framework 3 (FR3) and CDR3 probes. Out of > 200 FR3-hybridizing colonies, < or = 5 colonies also hybridized with the CDR3 probe. Colonies which hybridized with both these probes were sequenced, and none of these sequences matched even closely the CDR3 expressed by the malignant clone. These results make the existence of a pre-class switch malignant cell unlikely in MM. Overall, these results suggest that the malignant clone in MM derives from a cell late in B lymphocyte development.

Longitudinal studies of blood pressure in children

A longitudinal study of six years was conducted to find out the pattern of longitudinal changes of blood pressure and to affirm the "tracking phenomenon" of blood pressure in children in China. We initially measured blood pressure and related parameters of 2,946 children (aged 4-14 years) in 1981 at Fanshan county, Beijing, and then two follow-up remeasurements were conducted in 1985 and 1987, respectively. The results indicated that: the average level of blood pressure increases with age even after adjusting for height and weight; tracking coefficients of systolic blood pressure range from weak to moderate levels, increasing with age. Only 30% of the children whose systolic blood pressure was beyond the 90th percentile of the systolic pressure distribution at the first examination remained at the same region after four years. Multiple stepwise regression was used to determine factors correlated with blood pressure. Our results indicate that systolic blood pressure in children is correlated with body weight, pulse rate, serum glucose and HDL-C, while diastolic blood pressure is correlated only with pulse rate and serum glucose.

Methods for the estimation of failure distributions and rates from automobile warranty data

We consider the occurrence of warranty claims for automobiles when both age and mileage accumulation may affect failure. The presence of both age and mileage limits on warranties creates interesting problems for the analysis of failures. We propose a family of models that relates failure to time and mileage accumulation. Methods for fitting the models based on warranty data and supplementary information about mileage accumulation are presented and illustrated on some real data. The general problem of modelling failures in equipment when both time and usage are factors is discussed.

[The reversing effect of 4-hydroxycarbophenyl retiamide (R II) on the malignant phenotype of mouse forestomach carcinoma (MFC) cell line and the mechanism of its action]

4-hydroxycarbophenyl retiamide (R II) is a new synthetic analogue of retinol, but with lower toxicity than retinoic acid. We studied its induction effects and its effects on some malignant phenotypes of the MFC cell line. The mechanism of these effects was also explored. MFC cells were grown in complete RPMI 1640 medium supplemented with 10(-5) mol/L R II for five passages. By then the cell growth rate slowed down; the rate of 3H-TdR incorporation and the colony-forming capacity of MFC cells decreased; morphologically, the cells became epithelial rather than fibroblastic with various degrees of polarization. Further investigation about the mechanism of these changes was also undergone. First by flow cytometry, it was shown that the R II-treated cells were retained in G1 phase. Second, dot blot hybridization showed a decrease of more than 61% of c-myc mRNA and an increase of more than 52% of v-fos mRNA. The major chromosome distribution changed from 54-56 to 46-54 with an increase in diploid. Scanning microscopic examination showed that the R II-treated cells were covered by numerous microvilli and pseudopodia with round terminal expansion in contrast to the ruffle protrusions and leaf-like pseudopodia of control cells. All the results suggested that R II could reverse some malignant phenotypes of MFC cells.

Mutational analysis of the translational signal in the human cytomegalovirus gpUL4 (gp48) transcript leader by retroviral infection

A short upstream open reading frame (uORF2) in the human cytomegalovirus (CMV) gpUL4 (gp48) transcript leader is conserved among CMV strains and inhibits translation of a downstream cistron. Remarkably, this inhibitory effect depends on the amino acid coding information of uORF2, at least in transient transfection assays in diploid human fibroblasts. Using retroviral vectors, we now report that the gp48 leader inhibits downstream translation in multiple additional cell types, even when expressed from a stably integrated gene, and on a transcript containing an additional kilobase of complex leader sequences. The magnitude of inhibition can be augmented approximately 3- to 10-fold by replacing the context of nucleotides flanking the wild-type initiation codon of uORF2 with an optimal context, suggesting that leaky scanning past the wild-type AUG codon accounts for translation of the downstream cistron. Using an in vivo mutagenesis protocol that relies on reverse transcriptase infidelity, we isolated mutants in which the inhibitory effect of the gp48 leader was inactivated as a result of alterations in the coding information of uORF2. These studies demonstrate that, independent of the cell type or expression system used, CMV gp48 uORF2 is a potent translational inhibitory element.

The hematopoietic stem cell antigen, CD34, is not expressed on the malignant cells in multiple myeloma

Autologous stem cell transplantation has become an important therapy in multiple myeloma (MM). To develop adequate autograft purging methods, it is necessary to determine whether antigens expressed on early hematopoietic progenitors exist on malignant cells. The Ig heavy chain produced by the MM cells shows evidence of prior somatic mutation without intraclonal diversity. As a result, this sequence can be used as a specific marker to detect all members of the malignant clone. The Ig heavy chain sequence expressed by the MM cells was obtained in five patients with advanced disease. Patient specific oligonucleotide primers were designed based on the complementarity determining regions (CDR) of each MM Ig sequence and used to amplify DNA by polymerase chain reaction for the detection of malignant cells. A highly purified collection of CD34+ cells was obtained after passage of the initial bone marrow cells through an immunoadsorption column and fluorescence-activated cell sorting. Despite an assay sensitivity of 1 tumor cell in 2,500 to 44,000 normal cells, none of the CD34+ samples showed product with the myeloma-specific CDR primers. Therefore, positive selection for cells bearing this antigen should yield a tumor-free autograft capable of providing hematopoietic recovery after myeloablative chemotherapy.

Mutagenicity of 1,3-butadiene inhalation in somatic and germinal cells of mice

Inhalation exposure of mice to 50, 200, 500 or 1300 ppm of 1,3-butadiene for 6 h per day for 5 consecutive days caused micronuclei in mouse bone marrow and peripheral blood erythrocytes. The dose response was non-linear. The slope of the curve flattened with increasing exposure concentration. Coat color spots were found in the mouse spot test after exposure of pregnant females on pregnancy days 8-12 to 500 ppm of 1,3-butadiene. Dominant lethal mutations were induced in spermatozoa and late spermatids after exposure of male mice to 1300 ppm with the 5-day exposure regimen. Thus, in the mouse 1,3-butadiene is a somatic and germ cell mutagen.

A matrix metalloproteinase expressed on the surface of invasive tumour cells

Gelatinase A (type-IV collagenase; M(r) 72,000) is produced by tumour stroma cells and is believed to be crucial for their invasion and metastasis, acting by degrading extracellular matrix macro-molecules such as type IV collagen. An inactive precursor of gelatinase A (pro-gelatinase A) is secreted and activated in invasive tumour tissue as a result of proteolysis which is mediated by a fraction of tumour cell membrane that is sensitive to metalloproteinase inhibitors. Here we report the cloning of the complementary DNA encoding a new matrix metalloproteinase with a potential transmembrane domain. Expression of the gene product on the cell surface induces specific activation of pro-gelatinase A in vitro and enhances cellular invasion of the reconstituted basement membrane. Tumour cells of invasive lung carcinomas, which contain activated forms of gelatinase A, were found to express the transcript and the gene product. The new metalloproteinase may thus trigger invasion by tumour cells by activating pro-gelatinase A on the tumour cell surface.

Changes in the cytopathic effects of human immunodeficiency virus type 1 associated with a single amino acid alteration in the ectodomain of the gp41 transmembrane glycoprotein

A human immunodeficiency virus type 1 mutant with a single amino acid change (designated 596 W/M) in the ectodomain of the gp41 transmembrane envelope glycoprotein replicated in T-cell lines and in CD4-positive peripheral blood mononuclear cells identically to the wild-type virus. However, the cytopathic effects associated with infection by the mutant virus were altered, with a marked attenuation of syncytium formation and a significant delay in single-cell lysis relative to those of the wild-type virus-infected culture. The 596 W/M mutant is apparently defective in a function that is dispensable for virus entry but that contributes to the efficiency of induction of viral cytopathic effects.

Transformation of Mycoplasma gallisepticum with Tn916, Tn4001, and integrative plasmid vectors

Mycoplasma gallisepticum causes respiratory disease in avian species, but little is known about its mechanism(s) of pathogenesis. These studies were undertaken in order to develop genetic systems for analysis of potential virulence factors. M. gallisepticum was transformed with plasmids containing one of the gram-positive transposons Tn916 or Tn4001, which inserted randomly into the mycoplasmal chromosome. Plasmids containing cloned chromosomal DNA were also constructed and tested for integration into regions of DNA homology derived either from chromosomal fragments or from the gentamicin resistance marker from Tn4001. These studies demonstrate that M. gallisepticum is amenable to transformation with both transposons and integrative vectors.

Esophageal balloon cytology and subsequent risk of esophageal and gastric-cardia cancer in a high-risk Chinese population

Linxian, China has some of the highest rates of esophageal/gastric cardia cancer in the world. In 1983, esophageal balloon cytology screening was performed in 3 communes in northern Linxian. Of the participants, 10,066 with no evidence of cancer were followed prospectively for 7 1/2 years to evaluate the ability of the initial cytologic diagnoses to identify individuals at increased risk for developing cancer of the esophagus or gastric cardia. A total of 747 incident cases of esophageal or cardia cancer and 322 deaths due to these tumors were identified during the follow-up period and used in this analysis. The risks for esophageal or cardia cancer incidence and mortality increased in parallel with the presumed severity of the 1983 Chinese cytologic diagnoses. After adjusting for potential confounding factors, relative risks for esophageal or cardia cancer incidence, by initial cytologic diagnosis, were normal = 1.00 (reference), hyperplasia = 1.25, dysplasia 1 = 2.20, dysplasia 2 = 4.22 and near-cancer = 5.96. Our results suggest that esophageal balloon cytology, as performed and interpreted in Linxian in 1983, successfully identified individuals at increased risk for developing cancer of the esophagus or gastric cardia.

An improved fragile X Southern blot probe without the CGGs eliminates background bands

The largest of the commonly used probes for Southern blot diagnosis of fragile X mental retardation syndrome spans the CGG repeat cluster in the FMR-1 gene. This probe causes the appearance of 'common' or 'constant' background bands which occasionally complicate the interpretation of autoradiographic results. By removing a 357 bp Sphl to Nhel fragment containing the CGGs from the probe pE5.1, we constructed a probe which eliminates the background bands yet allows the use of a large probe (4.8 kb) to detect changes in the diagnostic 5.2 kb genomic EcoRl band. This CGG-deficient probe has been used in routine diagnostic cases as well as in second round testing of pE5.1-probed cases where enlarged mutant bands are suspected to comigrate with the background bands.

Phosphofructokinase from mantle tissue of Mytilus galloprovincialis. Purification and effects of phosphorylation on the enzymatic activity

Phosphofructokinase purified from mantle tissue of the sea mussel Mytilus galloprovincialis, was phosphorylated "in vitro" by the catalytic subunit of cyclic AMP-dependent protein kinase. The incorporation of phosphate gave rise to an activation of the enzyme by increasing its affinity for fructose-6-phosphate, by decreasing its sensitivity to the inhibition by ATP and by enhancing the effect of allosteric activators (5'-AMP and fructose-2,6-bisphosphate). In addition, the effects of phosphorylation on the catalytic activity are pH-dependent.

A simple fragile X PCR assay with 7-deazaguanine-substituted DNA visualized by ethidium bromide

A deazaguanine-substituted DNA PCR product from FMR-1 (the fragile X mental retardation syndrome gene) can be efficiently visualized with ethidium bromide on standard agarose gels. Normal-sized alleles (less than 54 CGG repeats) generated strong, easily visible bands in the expected size range of 491-635 bp. Southern blot analysis and radioactive PCR on sequencing gels were used to verify that the 74 males (out of 245 total tested) whose DNA failed to generate a visible band contained premutations or full mutations. This technique can be used as an inexpensive screen for fragile X syndrome among developmentally delayed males.

Simultaneous determination of the optical constants and thickness of very thin films by using soft-x-ray reflectance measurements

A nonlinear, least-squares curve-fitting method is described that simultaneously determines the optical constants and the thickness of a very thin (≲ 100-Å) film from reflectance versus angle of incidence (R - θ) data measured in the soft-x-ray region. The method is applied to R - θ data obtained for very thin, sputtered films of carbon (65 Å thick) and gold (94 Å thick) at photon energies of 60-900 eV. The results show that the present method is capable of accurately determining the thickness of very thin films even for transparent materials, and that the obtained optical constants are in good agreement with values reported for films with a thickness of 1000 Å.

[Immunohistochemical observation of anti-human hepatocellular carcinoma monoclonal antibody HL2 in cancers]

Molecular weight of human hepatocellular carcinoma (HCC)-associated antigen-HL2 antigen was detected to be about 50,000 dalton by SDS-PAGE and Western blot. One hundred and twenty-seven paraffin sections of cancers and pathological liver tissue were tests by ABC immunohistochemical staining. MAb HL2 reacted with 62.7% HCC and also with 8 of the 10 stomach carcinomas but only with a few other digestive system carcinomas (pancreas carcinoma, rectum carcinoma and duodenum carcinoma) and hepatitis. MAb HL2 was negative in hepatocirrhosis and other tumors (vesica carcinoma, skin carcinoma, breast carcinoma, neurogliocytoma and carcinoma of the lung). The results suggest that MAb HL2 has values in diagnosis of HCC and differential diagnosis between HCC and other tumours. HL2 antigen might be a new tumor-associated antigen (TAA). Further study of HL2 antigen will significantly show the actions of TAA in the occurrence and development of tumor.

Inhibition of fatty acid delta 6- and delta 5-desaturation by cyclopropene fatty acids in rat liver microsomes

delta 6-Desaturation of linoleic acid and delta 5-desaturation of dihomo-gamma-linolenic acid were measured in liver microsomes from rats fed fresh Baobab seed oil containing cyclopropene fatty acids (malvalic acid and sterculic acid) or heated Baobab seed oil practically devoid of these fatty acids or control oil. The presence of cyclopropene fatty acids in the fresh Baobab oil diet highly depressed both desaturations, but delta 6- more than delta 5-desaturation. The decreased capacity of microsomes to desaturate was reflected in the lower arachidonic acid content in microsomal phospholipids from rats fed this oil. However it was also lower in rats fed heated oil although in vitro delta 6- and delta 5-desaturation were not depressed. When liver microsomes prepared from rats fed the control diet were used for the desaturation assays, the presence of free malvalic or sterculic acid in the medium, also highly depressed delta 6- and delta 5-desaturation. The incorporation of arachidonic acid, the product of delta 5-desaturation, into phospholipids was also highly depressed, while that of the precursor dihomo-gamma-linolenic acid was not. This suggests that cyclopropene fatty acids specifically inhibit incorporation of the delta 5-desaturation product into phospholipids or that they specifically inhibit desaturation of the substrate previously incorporated into a membrane phospholipid.

Transformation-sensitive cells in G2/M-phase are not promoted by TPA following 137Cs gamma-rays

Mouse C3H 10T1/2 cells are most sensitive to radiation-induced neoplastic transformation in the G2/M-phase of the cell cycle. When synchronized 10T1/2 cells were exposed to phorbol 12-myristate 13-acetate (TPA) after irradiation, transformation of cells not in the transformation-sensitive window was enhanced, but transformation of cells already in the transformation-sensitive window was not. Earlier work showed that (a) TPA enhances the frequency of transformation of both high and low dose-rate gamma-irradiated cells by about the same factor, but that (b) TPA enhances the transformation of cells exposed to low dose-rate fission spectrum neutrons appreciably less than cells exposed to high dose-rate fission spectrum neutrons. The latter observation is consistent with the inability of TPA to promote cells in the transformation-sensitive window and with the role of such cells in enhancing transformation by protracted doses of neutrons. The data provide a cellular basis for studying the biochemical/molecular aspects of TPA promotion in vitro.

Flow cytometric detection of micronuclei induced by chemicals in poly- and normochromatic erythrocytes of mouse peripheral blood

In order to standardize automated scoring for the in vivo micronucleus (MN) test a flow cytometric method which recognized micronucleated polychromatic erythrocytes (MPCE) and micronucleated normochromatic erythrocytes (MNCE) in mouse peripheral blood developed by Grawé et al. (1992) has been modified and applied. Blood samples were purified with 35% percoll solution and stained with the RNA-specific dye thiazole orange (TO) and with the DNA-specific dye Hoechst 33342 (HO) for dual laser flow cytometry. The TO fluorescent signals permitted the discrimination between polychromatic and normochromatic erythrocytes (PCE and NCE). Cytotoxic effects could be assessed by the reduction of PCE counts. The blue fluorescent signals of HO permitted the scoring of MN. The MPCE and MNCE were flow sorted for microscopic analysis and showed that 95% of the sorted cells actually contained MN. Three model chemicals, the clastogen mitomycin C, the aneugen colchicine and the industrial chemical acrylamide were tested at 24 h intervals after single intraperitoneal injection up to 72 h after treatment of male (102/ElxC3H/El)F1 mice. All three chemicals showed a dose-related maximum of the MPCE frequencies at 48 h while the MNCE frequencies stayed within the control range up to 72 h. The data obtained with the flow cytometric method were in good agreement with published results. The flow cytometric technique presented here is a fast, accurate and automated method for quantifying MPCE and MNCE in peripheral blood as an indicator of cytogenetic damage induced in the bone marrow and scored in peripheral blood samples. With minor modifications the technique will also be applicable to bone marrow samples.

[The relationship of duodeno-gastric reflux index to histological changes and nuclear DNA contents in gastric stump mucosa dysplasia]

Dysplasia of gastric stump mucosa in 35 cases was studied. Evaluation of the entero-gastric reflux index(EGRI) was carried out by a computer radioisotope scanning. Dysplasia nuclear DNA content was measured using an automatic image analysis system. The results showed: (1) The severity of dysplasia in gastric stump mucosa increased with the increase of the mean values of the EGRI. The difference among all groups was highly significant (P < 0.001). (2) There appeared to be a significant positive correlation between EGRI and IOD, 2cDI, AREA or FORM PF, the correlation coefficients were 0.8927 (P < 0.001), 0.8631 (P < 0.001), 0.7845 (0.001 < P < 0.005), 0.7692 (0.001 < P < 0.005), respectively. (3) Significant differences were found among all groups for the mean interval between initial surgery and endoscopic examination (P < 0.001). From this study, a close relationship between dysplasia and entero-gastric reflux of the gastric stump could be postulated.

Translational inhibition mediated by a short upstream open reading frame in the human cytomegalovirus gpUL4 (gp48) transcript

The human cytomegalovirus (CMV) virion glycoprotein gpUL4 (gp48) gene expresses a transcript that contains three AUG codons upstream from the one used to initiate synthesis of the gp48 protein. Previously we reported that the second of these AUG codons, AUG2, was necessary but insufficient for inhibition of downstream translation (M. Schleiss, C. R. Degnin, and A. P. Geballe, J. Virol. 65:6782-6789, 1991). We now demonstrate that the coding information of the upstream open reading frame initiated by AUG2 (uORF2) is critical for the inhibitory signal. Several missense mutations, particularly those involving the carboxy-terminal codons of uORF2, inactivate the inhibitory signal, while mutations that preserve the coding content of uORF2 uniformly retain the inhibitory signal. The uORF2 termination codon is essential for inhibition, but leader sequences further downstream are not critical. Conservation of uORF2 among clinical strains of CMV suggests that uORF2 provides an important function in the CMV infectious cycle. Although these results indicate that the peptide product of uORF2 mediates the inhibitory effect, we demonstrate that the uORF2 signal acts only in cis, and we propose a model of inhibition by the gp48 uORF2 signal.

Multifrequency cross-correlation phase fluorometry of chlorophyll a fluorescence in thylakoid and PSII-enriched membranes

We present here a comparative study on the decay of chlorophyll (Chl) a fluorescence yield in thylakoid membranes and photosystem II (PSII)-enriched samples, measured with multifrequency cross-correlation phase fluorometry. These measurements confirm the general conclusions of Van Mieghem et al. (Biochim. Biophys. Acta 1100, 198-206, 1992), obtained with a flash method, on the effects of reduction of the primary quinone acceptor (QA) on Chl a fluorescence yield of PSII. Different states of the reaction centers of PSII were produced by: (1) pretreatment with sodium dithionite and methyl viologen followed by laser illumination: the doubly reduced QA (QAH2) centers; (2) with laser illumination or pretreatment with diuron: QA- centers; and (3) the addition of micromolar concentration of dichlorobenzoquinone (DCBQ): oxidized QA centers. The data were analyzed with Lorentzian distribution as well as with multiexponential fluorescence decay functions. The analysis with Lorentzian distribution function showed that upon formation of QA-, the major lifetime distribution peak shifted to longer lifetimes: from 0.25 ns to 1.66 ns (pea thylakoid membranes) and from 0.24 ns to 1.31 ns (core PSII). However, when QAH2 was formed, the lifetime distribution peaks shifted back to shorter lifetimes (0.57-0.77 ns) both in thylakoids and PSII membranes. Multiexponential analysis showed three lifetime components: fast (40-400 ps), middle (300-1500 ps) and slow (5-25 ns). When QA- was formed in PSII centers, the amplitude of the fast component decreased, but both the amplitude and the lifetime of the middle component increased severalfold.(ABSTRACT TRUNCATED AT 250 WORDS)

Neoplastic transformation of C3H mouse embryo cells, 10T1/2: cell-cycle dependence for 50 kV X-rays and UV-B light

The variation of neoplastic transformation induced by 50 kV X-rays, and by solar-simulating UV-B light, was studied through the cell cycle of C3H mouse embryo cells designated 10T1/2. A mitotic shake-off method was used to harvest mitotic cells. The progression through the cell cycle of initially mitotic cells was followed as a function of time by flow cytometry, DNA labelling for passage through S-phase, and growth curves for cell number. At 2-3 h after shake-off, about 90% of the cells were in early G1-phase and by 15 h 60-70% of cells had reached S-phase. For 2.5 Gy, the transformation frequency per viable cell in M-phase was some five times higher than in S-phase. In contrast, at similar survival levels, UV-B light is less efficient in transforming mitotic cells. For both types of radiation, the frequency of neoplastic transformation per viable cell was roughly inversely proportional to survival.

Cytologic screening for esophageal cancer: results from 12,877 subjects from a high-risk population in China

Linxian, China, has one of the highest esophageal-cancer mortality rates in the world. In 1983, esophageal balloon-cytology screening was performed to identify subjects eligible for 2 nutrition-intervention trials in Linxian; 12,877 subjects had cytology slides which were satisfactory for diagnosis. Of the 12,649 subjects with squamous-cell diagnoses, 31% were normal by Chinese cytologic criteria; 38% showed hyperplasia; 21% showed dysplasia 1; 6% showed dysplasia 2; 2% showed near-cancer; and 2% showed cancer. Of the 1,471 subjects with columnar-cell diagnoses, 31% were normal; 44% showed hyperplasia; 16% showed dysplasia 1; 4% showed dysplasia 2; 2% showed near-cancer; and 3% showed cancer. Squamous dysplasia and cancer were more common among females than males, while columnar dysplasia and cancer showed male predominance. The prevalence of dysplasia and cancer of both cell types increased with age. The prevalence of squamous dysplasia was significantly higher than in earlier balloon-cytology screenings in Linxian, probably reflecting changes in cytologic classification.

Effects of amino acid changes in the extracellular domain of the human immunodeficiency virus type 1 gp41 envelope glycoprotein

Changes were introduced into conserved amino acids within the ectodomain of the human immunodeficiency virus type 1 (HIV-1) gp41 transmembrane envelope glycoprotein. The effect of these changes on the structure and function of the HIV-1 envelope glycoproteins was examined. The gp41 glycoprotein contains an amino-terminal fusion peptide (residues 512 to 527) and a disulfide loop near the middle of the extracellular domain (residues 598 to 604). Mutations affecting the hydrophobic sequences between these two regions resulted in two phenotypes. Some changes in amino acids 528 to 562 resulted in a loss of the noncovalent association between gp41 and the gp120 exterior glycoprotein. Amino acid changes in other parts of the gp41 glycoprotein (residues 608 and 628) also resulted in subunit dissociation. Some changes affecting amino acids 568 to 596 resulted in envelope glycoproteins partially or completely defective in mediating membrane fusion. Syncytium formation was more sensitive than virus entry to these changes. Changes in several amino acids from 647 to 675 resulted in higher-than-wild-type syncytium-forming ability. One of these amino acid changes affecting tryptophan 666 resulted in escape from neutralization by an anti-gp41 human monoclonal antibody, 2F5. These results contribute to an understanding of the functional regions of the HIV-1 gp41 ectodomain.

Cytochrome aa3 of Rhodobacter sphaeroides as a model for mitochondrial cytochrome c oxidase. The coxII/coxIII operon codes for structural and assembly proteins homologous to those in yeast

The coxII/coxIII operon of Rhodobacter sphaeroides cytochrome c oxidase has been sequenced and characterized by insertional inactivation/complementation analysis. The organization of the genes in this locus (coxII.orf1.orf3.coxIII) is the same as that of the equivalent operon of Paracoccus denitrificans (ctaC.ctaB.ctaG.ctaE), but unlike that of other bacteria whose cytochrome oxidase genes have been characterized so far. The predicted amino acid sequence homology with eukaryotic oxidases is also higher for Rb. sphaeroides (and P. denitrificans) than for other bacterial versions of the enzyme. The inactivation of coxII results in loss of the characteristic cytochrome oxidase spectrum from membranes of the mutant strain. Full recovery requires introduction into the bacterium of the complete operon containing coxII.orf1.orf3.coxIII; partial complementation yielding a spectrally altered enzyme is achieved with a plasmid containing coxII or coxII.orf1.orf3. These results indicate that the peptides ORF1, ORF3, and COXIII are all required for assembly of native cytochrome c oxidase, suggesting an oxidase-specific assembly or chaperonin function for the ORFs in Rb. sphaeroides similar to that observed for the homologous gene products in yeast, COX10 and COX11.