Cytochemical studies of metaphase chromosomes by flow cytometry

The cytochemical properties of metaphase chromosomes from Chinese hamster and human cells were studied by flow cytometry. This technique allows precise quantitation of the fluorescence properties of individual stained chromosome types. Chromosomes were stained with the following fluorescent DNA stains: Hoechst 33258, DAPI, chromomycin A3, ethidium bromide, and propidium iodide. The relative fluorescence of individual chromosome types varied depending on the stain used, demonstrating that individual chromosome types differ in chemical properties. Flow measurements were performed as a function of stain and chromosome concentration to characterize the number and distribution of stain binding sites. Flow analysis of double stained chromosomes show that bound stains interact by energy transfer with little or no binding competition. For most hamster chromosomes, there is a strong correlation between relative fluorescence and stain base preference suggesting that staining differences may be determined primarily by differences in average base composition. A few hamster chromosome types exhibit anomalous staining which suggests that some other property, such as repetitive DNA sequences, also may be an important determinant of chromosomal staining.     

An evaluation of procedures used in staging carcinoma of the cervix

A review of 227 cases of invasive carcinoma of the cervix was undertaken to determine the efficacy of procedures using in the staging of this disease. All patients had a pretreatment chest radiography and intravenous pyelogram. 96.5% had pretreatment cystoscopy, 98.6% had pretreatment proctoscopy, and 92% had a pretreatment barium enema. These patients were retrospectively staged on the findings of physical examination only. Each additional procedure was then evaluated by comparison with the initial staging. Cystoscopy and chest film findings each would have changed the clinical stage in fewer than 1% of cases, barium enema in 1.4%, and proctoscopy in 2.2%. No patient had a positive barium enema without a positive proctoscopy, while two patients had positive proctoscopies with negative barium enemas. The overall yield of positive findings by pretreatment intravenous pyelography was 7.3%. Lymphangiography, although inconsistently done, yielded positive findings in all stages. Chest radiographs, intravenous pyelography, proctoscopy, and lymphangiography are recommended as part of the pretreatment workup of patients with carcinoma of the cervix. Routine barium enema is no longer recommended, and cystoscopy is only recommended in patients with clinical stage IIB disease or greater.     

GENOMIC HARDWIRING AND PHENOTYPIC PLASTICITY OF TERPENOID-BASED DEFENSES IN CONIFERS

Over evolutionary history, conifers have faced a myriad of threats from phloem- and xylem-feeding insects, defoliating insects, and fungal pathogens. Among the trees defenses, terpenoids appear to play a major role by harming, disabling, deterring, repelling, or otherwise reducing the fitness of potential invaders. Each of the three classes of terpenoids in conifers, monoterpenes, sesquiterpenes, and diterpenes, are composed of a large number of representative compounds. In most cases, the presence of a particular terpenoid compound in the oleoresin or volatile emissions from a specific conifer can be accounted for by the expression of one of many committed terpene synthase (TPS) genes. However, while each TPS may produce one or a few major products, many produce a variety of minor products with relatively constant component ratios in the product blends. TPS genes exist in conifers in large and functionally diverse, yet monophyletic, gene families. Within these gene families, new biochemical functions of TPS appear to have evolved by gene duplication and changes in the amino acid sequence of the enzymes active site. In addition, TPS genes may be differentially expressed prior to, during, and following attack by insects or pathogens. Thus, while the production of any particular terpenoid is hardwired into a conifers genome, these trees have the capacity to change the mixture of terpenoids in oleoresin secretions and volatile emissions. Anatomical changes may also accompany induced terpenoid production, supplementing the plasticity of the molecular and biochemical events.     

The effect of treatment with clofibrate on hepatic triglyceride and lipoprotein lipase activities of post heparin plasma in male patients with hyperlipoproteinemia

Twelve male patients with hyperlipoproteinemia were treated with clofibrate, 1 g twice daily. Serum triglyceride concentration decreased on the average 28 +/- 6%. No significant change of serum cholesterol concentration occurred. Post heparin plasma lipoprotein lipase activity isolated and partially purified by heparin Sepharose affinity chromatography was determined quantitatively. During the clofibrate treatment this enzyme activity increased 48 +/- 9%. The post heparin hepatic triglyceride lipase did not change significantly. The possibility that the serum triglyceride-lowering effect of clofibrate might partly be explained by an increased removal rate of triglyceride rich lipoproteins through increased lipoprotein lipase activity is discussed.     

Blue lasing at room temperature in an optically pumped lattice-matched AlInN=GaN VCSEL structure

Laser action with low threshold average pump power density (~50 W - cm^-2 ) at room temperature is reported for a crack-free planar vertical cavity surface emitting laser (VCSEL) structure based on a bottom lattice-matched AllnN/GaN distributed Bragg reflector (DBR) and a top dielectric DBR. The cavity region, formed by n- and p-type GaN layers surrounding only three InGaN/GaN quantum wells, corresponds to a typical active region suitable for an electrically driven VCSEL. In addition to low threshold, a spontaneous emission coupling factor beta ~ 2 x 10^-10 is derived for this ready-to-be-processed laser structure.     

Ocular toxicity following topical application of anesthetic cream to the eyelid skin

BACKGROUND AND OBJECTIVE: The use of topical anesthetic cream in the periorbital region may be of clinical value. The potential for toxic effects from such use has not been studied in a controlled manner. This study was performed to evaluate the potential ocular toxicity of anesthetic cream topically applied to the eyelid in an animal model. MATERIALS AND METHODS: Ten rabbits underwent periorbital eutectic mixture of local anesthetics (EMLA) (2.5 percent lidocaine and 2.5 percent prilocaine) application and were observed for evidence of gross or microscopic ocular toxicity. Baseline external and anterior segment examinations were performed, including biomicroscopy and fluorescein staining, after which a standard quantity of EMLA cream (0.75 g) was applied along the upper eyelid and covered with an occlusive dressing. After 1 hour of treatment, the eyelid and anterior segment were examined for evidence of adverse reaction. The eyelids were excised and examined histopathologically. RESULTS: No significant adverse effects were noted on external lid and anterior segment examination. The histopathologic findings were within normal limits. CONCLUSIONS: This study suggests that external application of EMLA cream to the eyelid does not induce local toxicity in the rabbit model. The external application of EMLA cream may be safe in the periorbital region.     

7-Hydroxystaurosporine (UCN-01) induces apoptosis in human colon carcinoma and leukemia cells independently of p53

7-hydroxystaurosporine (UCN-01) is a more selective protein kinase C inhibitor than staurosporine. UCN-01 exhibits antitumor activity in experimental tumor models and is presently in clinical trials. Our study reveals that human myeloblastic leukemia HL60 and K562 and colon carcinoma HT29 cells undergo internucleosomal DNA fragmentation and morphological changes characteristic of apoptosis after UCN-01 treatment. These three cell lines lack functional p53, and K562 and HT29 cells are usually resistant to apoptosis. DNA fragmentation in HT29 and K562 cells occurred after 1 day of treatment while it took less than 4 h in HL60 cells. Cycloheximide prevented UCN-01-induced DNA fragmentation in HT-29 cells, but not in HL60 and K562 cells, suggesting that macromolecular synthesis is selectively required for apoptotic DNA fragmentation in HT29 cells. UCN-01-induced DNA fragmentation was preceded by activation of cyclin B1/cdc2 kinase. Further studies in HL60 cells showed that UCN-01-induced apoptosis was associated with degradation of CPP32, PARP, and lamin B and that the inhibitor of caspases (ICE/CED-3 cysteine proteases), Z-VAD-FMK, and the serine protease inhibitor, DCI, protected HL60 cells from UCN-01-induced DNA fragmentation. However, only DCI and TPCK, but not Z-VAD-FMK, inhibited DNA fragmentation in the HL60 cell-free system, suggesting that serine protease(s) may play a role in the execution phase of apoptosis in HL60 cells treated with UCN-01. Z-VAD-FMK and DCI also inhibited apoptosis in HT29 cells. These data demonstrate that the protein kinase C inhibitor and antitumor agent, UCN-01 is a potent apoptosis inducer in cell lines that are usually resistant to apoptosis and lack p53 and that caspases and probably serine proteases are activated during UCN-01-induced apoptosis.