[Aberrant expression of immunoglobulin germline gene C mu in leukemias]

OBJECTIVE

To investigate the significance of immunoglobulin germline gene C mu expression in leukemias.

METHODS

Immunoglobulin germline gene C mu transcripts in 63 bone marrow samples from 59 leukemia patients were examined by RT-PCR.

RESULTS

Germline C mu transcripts could be identified in 17 of 26 AML, 9 of 12 ALL, 4 CML-BC and 2 CLL patients. HLA-DR was expressed in 80% C mu(+) patients and in 92.9% C mu(+) AML patients. In 10 normal bone marrow or peripheral blood samples C mu transcripts were undetectable.

CONCLUSION

Leukemogenesis in most acute leukemia may originate from the common progenitors of early B-lymphoid and myeloid cells.

[Study on expression of nm23-H1 gene in laryngeal cancer tissues]

The nm23 gene is a metastasis suppressor gene. There are now two known isotypes of human nm23, namely nm23-H1 and nm23-H2. Several investigators have reported that reduced expression of nm23-H1 is associated with metastasis or disease progression in some of the tumor cases. In this study, the expression of nm23-H1 mRNA in the human laryngeal squamous cell carcinoma was investigated by Northern blot analysis. The levels of nm23-H1 mRNA were higher in cancers (n = 31) than in the adjacent normal tissues (n = 7), but the difference was not significant (P > 0.05). There was a significant decrease of nm23-H1 mRNA levels in tumors with lymph node metastasis (n = 11) as compared with those without (n = 20) (P < 0.01). Cancer tissues in clinical stages III-IV. (n = 23) also exhibited lower levels of nm23-H1 mRNA expression than those in stages I-II (n = 8) (P < 0.05). These results suggest that the nm23-H1 gene may play a role in the suppression of lymph node metastasis or disease progression in laryngeal cancer.

Fine needle aspiration biopsy of the penis: transitional cell carcinoma of the urinary bladder with mucinous differentiation

We report a case of transitional cell carcinoma of the urinary bladder metastatic to the penis. The diagnosis was established by fine needle aspiration biopsy (FNAB). Malignant cells showed mucinous differentiation. Ancillary studies carried out in the FNA material as well as in the primary bladder carcinoma suggested transitional cell carcinoma with mucinous differentiation. FNAB proved to be effective in diagnosing a secondary neoplasm to the penis. Mucoid differentiation of urothelial cells can be seen in FNAB specimens and might pose a problem in differential diagnosis.

[Studies on cloned genomic differential DNA fragments extracted from esophageal carcinoma and non-cancerous esophageal tissues in Linxian County]

OBJECTIVE

To isolate the genes involved in carcinogenesis of esophageal cancer and to provide a molecular marker for screening and early detection of it in susceptible individuals.

METHODS

DNA extracted from 12 matched pairs of esophageal cancer and non-cancerous tissues in patients of Linxian County, Henan Province, a high incidence area for esophageal cancer, and differential DNA fragments were isolated with arbitrary primer polymerase chain reaction (AP-PCR), cloned and sequenced. Restriction endonuclease Dra I and Hind III were used to digest genomic DNA in the pair-matched cancerous and non-cancerous esophageal tissues for Southern blot analysis.

RESULTS

There was a randomly amplified differential DNA fragment of about 1.0 kb in cancerous tissues in three of the twelve cases with esophageal cancer, but no such fragments could be found in corresponding non-cancerous tissues. Sequence analysis showed that no homologous DNA in GeneBank database as same as 11T differential DNA fragments. Southern blot analysis showed that there was significant difference between pair-matched cancerous and non-cancerous tissues.

CONCLUSION

11T differential DNA fragment appeared during carcinogenesis of the esophagus, and further investigations were needed to study if it could be regarded as a new kind of oncogene or a biomarker of it.

Decreased citrate improves iron availability from infant formula: application of an in vitro digestion/Caco-2 cell culture model

We have applied an in vitro digestion/Caco-2 cell culture model to the assessment of iron availability from human milk and a generic cow's milk-based infant formula. Experiments were designed to determine the availability of iron from human milk relative to infant formula and whether known promoters of iron absorption would increase Caco-2 cell iron uptake and availability from the infant formula. In addition, we sought to determine if decreasing the citrate concentration in the infant formula would increase the iron uptake. Although approximately twice as much iron was in solution from digests of the infant formula relative to that of human milk, smaller or equal amounts of iron were taken up from the infant formula relative to the human milk digest. These results are qualitatively similar to in vivo studies. Addition of known iron uptake promoters to infant formula did not enhance Caco-2 cell iron uptake from the infant formula digest, indicating that the iron in the infant formula existed predominantly in a tightly bound unavailable form(s). Enzymatic pretreatment of the infant formula with citrate lyase and oxalacetate decarboxylase decreased the citrate concentration by 67% and resulted in a 64% increase of iron in solution, which corresponded to a 46% increase in the cell iron uptake. Iron uptake from the "low citrate" formula plus cysteine was 102% greater relative to the nontreated formula. The results indicate that too much citrate can reduce iron uptake, particularly if it is present at concentrations greater than promoters such as ascorbic acid and cysteine.

Electrocardiographic Changes and Mortality Due to Myocardial Infarction in Rats With or Without Imidapril Treatment

BACKGROUND: Various angiotensin-converting enzyme inhibitors are known to improve heart function and prolong survival in patients and animals after myocardial infarction. Because myocardial infarction is known to induce arrhythmias, this study tested the hypothesis that early treatment with the angiotensin converting enzyme inhibitor imidapril reduces mortality during acute myocardial infarction because of protective effects against arrhythmogenesis. METHODS AND RESULTS: Rats were randomly divided into four groups: sham control, myocardial infarction, sham plus imidapril, and myocardial infarction plus imidapril. Myocardial infarction was produced by ligation of the left anterior descending coronary artery. Treated rats received imidapril (1 mg/kg/day) through a gastric tube beginning 1 hour after coronary occlusion; control rats received tap water. Electrocardiogram (ECGs) were recorded 1, 3, 7, and 21 days postocclusion. Infarct size and scar weight were determined at 21 days in the myocardial infarction groups with and without imidapril treatment. ECGs of untreated rats showed ST-segment changes, abnormal Q waves, premature ventricular complexes, and QT(c) prolongation 1-21 days after coronary occlusion. Total mortality in 21 days averaged 35% in untreated rats; mortality within 48 hours was 30%. On the other hand, imidapril-treated rats showed fewer ST-segment changes, fewer abnormal Q waves, and a decreased incidence of premature ventricular complexes after coronary occlusion; the ST-segment and QT(c) interval returned to basal values within 1 week after occlusion. Imidapril treatment did not affect the ECG pattern in sham-treated control animals. Total mortality in the imidapril-treated group in 21 days after infarction was 22.5%; mortality within 48 hours was 20% (P <.05 compared with the untreated infarction group). Infarct size and scar weight caused by coronary occlusion did not differ in the untreated and imidapril-treated groups. CONCLUSIONS: Early treatment with imidapril markedly decreases mortality in rats after acute myocardial infarction. The lower mortality is not associated with a decrease in infarct size but is consistent with a protective effect of the drug against arrhythmogenesis.

Role of the Fas/Fas ligand pathway in apoptotic cell death induced by the human T cell lymphotropic virus type I Tax transactivator

Two distinct human diseases have been described in association with human T cell lymphotropic virus type I (HTLV-I) infection: adult T cell leukaemia and tropical spastic paraparesis/HTLV-I-associated myelopathy. Although comprehensive understanding of specific mechanisms underlying pathogenesis of either disease has not yet been achieved, the viral regulatory protein Tax is believed to play a significant role. Previous studies demonstrated the potential of Tax to transform host cells. Here, it is shown that the Tax transactivator has in addition the potential to induce T cell death by apoptosis. Using an inducible system (Jurkat cell line JPX-9), significant apoptotic cell death upon Tax expression was observed. In an attempt to detect the cellular genes mediating this effect, it was found that induction of Tax was associated with marked upregulation of the Fas ligand (FasL) gene. Tax-induced apoptosis was inhibited when the Fas/FasL pathway was interrupted by YVAD-cmk, the inhibitor of ICE-like proteases. Transient expression experiments provided additional support for the putative role of endogenous FasL in Tax-induced apoptosis. Upon cotransfection with Tax-expressing plasmid, the transcriptional activity of the FasL promoter was found to be significantly upregulated in Jurkat cells and several other cell lines, as measured by reporter gene expression. Furthermore, cotransfection using different Tax mutants demonstrated that both CREB and NF-kappaB activation domains of Tax protein were required for the transactivation to take effect.

[Detection of P-glycoprotein in squamous cell carcinoma of larynx]

The multidrug resistance (MDR) of malignant tumor is a troublesome problem in the chemotherapy. One established mechanism of multidrug resistance is elevated expression of the P-glycoprotein (PGP). JSB1 (which is a special monoclonal antibody of human MDR, PGP) was used to examine the expression of PGP by immunohistochemistry in 23 specimens of squamous cell carcinoma of larynx. The expression of JSB1 in 10 normal laryngeal tissue specimens was also studied, no positive result was found. Of the 23 laryngeal cancer specimens, positive reaction to JSB1 was showed in 15, and there was no relationship between the positive expression, and the tumor differentiation, T staging and lymph-node metastasis. However, by using another newly developed monoclonal antibody C219, a different result was obtained from specimens of the same patients.

Basilar membrane velocity noise

Basilar membrane (BM) noise, measured as a velocity signal under the quiet acoustic condition, was investigated in the guinea pig. The cochleas of anesthetized young healthy guinea pigs were surgically exposed and a hole was made on the lateral wall of the scala tympani of the first cochlear turn for visualization of the BM and measurement of the BM velocity with a laser interferometer. The amplitude and frequency of the BM velocity noise were analyzed by a spectrum analyzer under different conditions. The spectrum of the BM velocity noise was a band limited function with a peak velocity at the topographic best frequency of the measured location on the BM. The peak velocity ranged to about 8 microm/s and depended on the physiological condition of the cochlea. Saline blockage of the external auditory canal or the middle ear did not change the BM noise. BM noise was much smaller, or was not evident, when the cochlear sensitivity decreased. The suppression tuning curve of the BM velocity noise indicates that the maximum suppression caused by an acoustic pure tone occurred at the best frequency location. A low sound level wide band acoustic noise given to the external ear canal produced a spectrum function having the same frequency and amplitude response as the BM noise. Electrical stimulation of the crossed olivocochlear bundle significantly depresses the BM velocity noise. These data demonstrate that the BM noise is a representation of internal rather than external noise. The amplitude and frequency of the BM noise reflect the usual cochlear sensitivity and frequency selectivity. Since the organ of Corti in the sensitive cochlea is a highly sensitive and tuned mechanical system, the internal (to the animal) noise responsible for the BM noise may originate from mechanical vibrations remote from the cochlea and propagated to the ear, or may be caused by Brownian motion of cellular structures in the cochlea.

[Research on basilar membrane vibration of guinea pigs elicited by direct current pulse]

To investigate the electromotility of basilar membrane (BM) of guinea pigs in vivo, a couple of Platinum-iridium wire electrodes were placed into holes drilled in the scala vestibuli and scala tympani on the basal turn of cochlea separately. The organ of Corti was stimulated with rectangular direct current pulses. The displacement and velocity of BM were measured with Laser Doppler velocimeter. The results indicated that the displacement of BM elicited by current moved toward the scala where positive current was injected. The waveform of BM displacement was corresponding to the rectangular pulse of electric current step. Ringing responses could be seen at the onset and offset of current pulse that was the transient responses of outer hair cells. The frequency of the ringing was the same as that of characteristic frequency of partition in BM. It is supposed that the ringing of BM is an active process of depletive energy and participate with cochlear amplifier. In the insensitive cochlea or dead animal, direct current can still elicit a BM displacement but the ringing response is decreased or disappeared. This phenomenon is probably because of metabolic disturbance in damaged outer hair cells. The BM vibration induced by direct current is similar to that of induced by acoustic stimulation, which can transfer to other partition of BM by traveling wave. This characteristic has laid a foundation of electromotile hearing and electrically evoked otoacoustic emission.

[Effect of platelet derived growth factor on the growth of human glomerular mesangial cells in vitro]

OBJECTIVE

To study the effect of plateletderived growth factor (PDGF) on the growth of human glomerular mesangial cells (MsC) in vitro.

METHODS

Immunohistochemistry for the detection of BrdU positive cells; [3H] proline incorporation for the bioactive assay of total amount of collagen; and Northern blot analysis for the determination of fibronectin (FN) alpha 1 (IV) collagen and c-myc mRNA expression.

RESULTS

The cell labelling index (LI) of BrdU incorporation in the PDGF group is 34.5% higher than that in the normal group, which was 19.5% (P < 0.01), The total amount of collagen secreted by MsC within cells and outside of cells in the PDGF group were 2.69 +/- 0.60% and 3.87 +/- 0.65% respectively, much higher than that of the normal group, which were 1.25 +/- 0.50% and 1.61 +/- 0.51% respectively (P < 0.01). Northern blot analysis revealed an increase of FN, Col IV, c-myc mRNA levels in the PDGF group.

CONCLUSION

PDGF can stimulate cell proliferation, synthesis of collagen and enhance FN, Col IV, c-myc mRNA expression. It is possible that PDGF may play an important role in the development and progression of glomerulopathy.

[Inhibition of 5 compounds from Bidens bipinnata on leukemia cells in vitro]

In vitro, inhibition of 5 compounds from Bidens bipinnata on two leukemia cells HL-60 and V397 is presented by determination of MTT living cell in this paper. The result show that the compounds have the action of inhibition, IC50 on V937 < or = 60 micrograms/ml.

Characterization of radiation-induced apoptosis in rodent cell lines

For REC:myc(ch1), Rat1 and Rat1:myc(b) cells, we determined the events in the development of radiation-induced apoptosis to be in the following order: cell division followed by chromatin condensation, membrane blebbing, loss of adhesion and the uptake of vital dye. Experimental data which were obtained using 4He ions of well-defined energies and which compared the dependence of apoptosis and clonogenic survival on 4He range strongly suggested that in our cells both apoptosis and loss of clonogenic survival resulted from radiation damage to the cell nucleus. Corroboratory evidence was that BrdU incorporation sensitized these cells to radiation-induced apoptosis. Comparing the dose response for apoptosis and the clonogenic survival curves for Rat1 and Rat1:myc(b) cells, we concluded that radiation-induced apoptosis contributed to the overall radiation-induced cell inactivation as assayed by clonogenic survival, and that a modified linear-quadratic model, proposed previously, modeled such a contribution effectively. In the same context, the selective increase in radiation-induced apoptosis during late S and G2 phases reduced the relative radioresistance observed for clonogenic survival during late S and G2 phases.

Diorganotin(IV) antitumor agent. (C2H5)2SnCl2 (phen)/nucleotides aqueous and solid-state coordination chemistry and its DNA binding studies

This contribution reports a solution and solid-state study of the aqueous nucleotide coordination chemistry of the diethyltin(IV) antitumor agent, (C2H5)2SnCl2(phen). [trans-en2Os(eta-H2)] (CF3SO3)2, a versatile 1H NMR probe for biomolecules, is first used to investigate the interaction of (C2H5)2SnCl2(phen) with DGMP in neutral aqueous solution, and then the synthesis of mixed-ligands complexes formulated as (C2H5)2SnCl(phen)(Nu) (Nu is nucleotide) by reactions of (C2H5)2SnCl2(phen) with equimolar nucleotides under biologically relevant conditions is described. The new complexes were characterized by 500 MHz 1H, 31P NMR spectra; these spectroscopic data suggest that one of cis-chloro atoms in (C2H5)2SnCl2(phen) is substituted by nucleotide, and that Sn(IV) is directly coordinated to the phosphate group of the nucleotide. No evidence was found for the coordination via donor atoms of the base. On the basis of the above model studies, absorbance, fluorescence and cyclic voltammetric methods, viscosity determination, as well as agrose gel electrophoresis of superhelical pBR322 plasmid DNA were used to study the interaction of (C2H5)2SnCl2(phen) with DNA. The results indicate that (C2H5)2SnCl2(phen) binds to DNA by double modes. The drug first reacts electrostatically with the sugar-phosphate backbone of DNA; this results in changes of DNA conformation, and then phen ligand can intercalate into double-helix DNA and cause unwinding of the DNA.

Down-regulation of gadd153 by c-myc in rat fibroblasts and its effect on cell growth and radiation-induced apoptosis

Using differential display reverse transcription PCR (DDRT - PCR), we found that a 360 bp cDNA fragment was absent in several c-myc transfected rat fibroblasts: REC:myc, REC:myc + ras and rat1-myc. These cells also showed enhanced sensitivity to gamma ray-induced apoptosis. This cDNA fragment was present in the parental REC (Rat Embryo Cells) and rat1 cells, and in c-Ha-ras transfected REC (REC:ras), all of which were relatively resistant to gamma ray-induced apoptosis. The cDNA fragment was subsequently cloned and used as a probe to screen a rat1 cDNA library, and identified as one of the growth arrest and DNA damaging-inducible genes, gadd153. In addition to the down-regulation of rat gadd153 in all the c-myc transfectants, methyl methanesulfonate (MMS)-induced transcription of the gadd153 was attenuated. The rat1-myc cells, when successfully transfected with and stably expressing the rat gadd153, showed a significantly longer doubling time compared to the parental cells. However, overexpression of gadd153 in rat1-myc cells did not affect gamma ray-induced apoptosis. Thus, the suppression of gadd153 appears to be inversely correlated with that of myc, but not involved in the myc-dependent apoptotic pathway.

Control of daughter cell fates during asymmetric division: interaction of Numb and Notch

During development of the Drosophila peripheral nervous system, a sensory organ precursor (SOP) cell undergoes rounds of asymmetric divisions to generate four distinct cells of a sensory organ. Numb, a membrane-associated protein, is asymmetrically segregated into one daughter cell during SOP division and acts as an inherited determinant of cell fate. Here, we show that Notch, a transmembrane receptor mediated cell-cell communication, functions as a binary switch in cell fate specification during asymmetric divisions of the SOP and its daughter cells in embryogenesis. Moreover, numb negatively regulates Notch, probably through direct protein-protein interaction that requires the phosphotyrosine-binding (PTB) domain of Numb and either the RAM23 region or the very C-terminal end of Notch. Notch then positively regulates a transcription factor encoded by tramtrack (ttk). This leads to Ttk expression in the daughter cell that does not inherit Numb. Thus, the inherited determinant Numb bestows a bias in the machinery for cell-cell communication to allow the specification of distinct daughter cell fates.

Dosage effects on gene expression in a maize ploidy series

Previous studies on gene expression in aneuploids revealed numerous trans-acting dosage effects. Segmental aneuploidy of each varied chromosomal region exhibited predominantly inverse effects on several target genes. Here, dosage regulation was examined in a maize (Zea mays L.) ploidy series where the complete genomic complement is varied. Total RNA from leaf tissue of monoploid, diploid, triploid, and tetraploid plants (1x, 2x, 3x, and 4x, respectively) was analyzed for the expression of 18 genes. For most tested genes, the transcript level per cell is directly proportional to structural gene dosage; that is, on a per genome basis, there is approximately equal expression among the four ploidies. Exceptional cases show a negative correlation of expression with ploidy or a positive correlation greater than expected from the structural gene dosage. These studies suggest that, in general, as structural gene dosage increases in multiples of the monoploid complement, the absolute level of gene expression per cell increases. In contrast, addition or subtraction of only a single chromosome arm tends to alter gene expression patterns extensively. The combined results of the euploid and aneuploid studies suggest that aneuploid effects result from an altered stoichiometry of the factors contributing to the mechanisms of gene expression.

Mutational studies of conserved residues in the dimer interface of nerve growth factor

An understanding of the structure-function relationship of nerve growth factor (NGF) requires precise knowledge of all the residues and regions that participate in NGF receptor binding, receptor activation, and biological activity. Seven recombinant human NGF mutants having alanine substituted for residues located either in the NGF dimer interface or beta-strand region were studied to determine the role of each amino acid residue in NGF biological activity. F86A, T91A, R100A, and R103A remained nearly full active with 61, 120, 91, and 73% of wild-type activity, respectively, in the PC12 cell bioassay. Hydrophobic core and dimer interface residues Y52, F53, and F54 were studied in more detail. Y52A and F54A were expressed in very low levels, suggesting that these two residues may be important for protein stability. Y52A retained full biological activity (91%). F53A had a 20- and 70-fold reduction in biological activity and TrkA phosphorylation, respectively, with only a 5- to 10-fold effect on TrkA binding and no effect on low-affinity receptor binding. F54A had significantly decreased TrkA phosphorylation and biological activity (40-fold). The results suggest that F53 and F54 may play a structural role in TrkA receptor activation subsequent to binding.

[Wound infection and recurrence after total laryngectomy]

95 patients who received total laryngectomy for laryngeal carcinoma were reviewed. They were divided into two groups, those with postoperative wound infection and those without. The relations between postoperative wound infection and local recurrence were discussed. The results showed that the recurrence rate of postoperative infection group was higher than that of no postoperative infection (P < 0.001), and the patients with gram-negative bacilli infection also had much higher recurrence rates (P < 0.05). For the laryngeal cancer, the development of a wound infection after total laryngectomy may be related to the local tumour recurrence within one year.