Showing papers on "Ultraviolet light published in 1995"

Physiological Basis of Myocardial Contrast Enhancement in Fast Magnetic Resonance Images of 2-Day-Old Reperfused Canine Infarcts

Abstract: Background Contrast-enhanced fast magnetic resonance (MR) images of acute, reperfused human infarcts demonstrate regions of hypoenhancement and hyperenhancement. The relations between the spatial extent and time course of these enhancement patterns to myocardial risk, infarct, and no-reflow regions have not been well characterized. Methods and Results The proximal left anterior descending coronary artery was occluded in 11 closed-chest dogs for 90 minutes followed by 2 days of reperfusion. Regional blood flow was determined by use of radioactive microspheres. The animals were studied at the 2-day time point with contrast-enhanced fast MRI (Signa 1.5 T, General Electric). Thioflavin-S was administered to demarcate no-reflow regions. The hearts were then excised, sectioned into five base-to-apex slices, stained with 2,3,5-triphenyltetrazolium chloride (TTC), and photographed under room light (for TTC) and ultraviolet light (for thioflavin). The spatial extents of thioflavin-negative, TTC-negative, and risk regions were compared planimetrically with MRI hypoenhanced and hyperenhanced regions. The spatial locations of subendocardial hypoenhancement in MR images correlated closely with those of thioflavin-negative regions. Microsphere blood flow in these regions was significantly reduced compared with remote regions (0.37±0.09 versus 0.88±0.10 mL/min per gram, respectively, P <.001) and with baseline (0.37±0.09 versus 0.87±0.15 mL/min per gram, P <.01). The spatial extent of hyperenhancement was smaller than the risk region ( r =.64, slope=0.48, P <.001) but highly correlated with TTC-negative regions and were, on average, 12% larger ( r =.93, slope=1.12, P =.035). Conclusions In contrast-enhanced MR images of 2-day-old reperfused canine infarcts, myocardial regions of hypoenhancement are related to the no-reflow phenomenon. Approximately 90% of the myocardium within hyperenhanced regions is nonviable.

Attraction of kestrels to vole scent marks visible in ultraviolet light

Abstract: IN northern Europe, broad four-year oscillations in small rodent and raptor populations are synchronous over hundreds of square kilometers1–6. Crashes in vole populations can induce wide emigration (> 1,000 km) of their predators7 –9, but almost nothing is known about how predators rapidly detect areas of vole abundance. Here we report on laboratory and field experiments on voles (Microtus agrestis) and kestrels (Falco tinnunculus). Voles mark their runaways with urine and faeces, which are visible in ultraviolet light. Wild kestrels brought into captivity were able to detect vole scent marks in ultraviolet light but not in visible light. In the field, kestrels hunted preferentially near experimental nest-boxes where artificial trails were treated with vole urine and faeces. We suggest that kestrels flying over an area can see and use vole scent marks to assess vole numbers. This ability would enable kestrels to 'screen' large areas in a relatively short time. Our results provide a novel explanation for how raptors detect patches of high vole densities without prior knowledge of local food resources.

High brightness electroluminescent device emitting in the green to ultraviolet spectrum and method of making the same

Abstract: A green-blue to ultraviolet light-emitting optical device, e.g. a green-blue to ultraviolet emitting laser or a green-blue to ultraviolet emitting diode, comprising a green-blue to ultraviolet light emitting gallium nitride material on a base structure including a silicon carbide substrate, which preferably consists of 2H-SiC, 4H-SiC, or a-axis oriented 6H-SiC. The carrier mobility and the transparency of the silicon carbide substrate are optimized by the selection of orientation and polytype, thus enhancing device performance. The light-emitting diodes may incorporate a structural modification to increase the light output comprising a dielectric Bragg mirror beneath the LED structure, made of alternating layers of AlN, GaN, InN or their alloys. Methods for making such light-emitting diodes are provided, including a technique for defining individual devices by mesa etching which avoids possible damage to the active area during dicing.

The ecology of nostoc

Abstract: Nostoc is a genus of filamentous cyanobacteria that can form macroscopic or microscopic colonies and is common in both terrestrial and aquatic habitats. Much of the success of Nostoc in terrestrial habitats is related to its ability to remain desiccated for months or years and fully recover metabolic activity within hours to days after re-hydration with liquid water. Nostoc can also withstand repeated cycles of freezing and thawing and, thus, is an important component of extreme terrestrial habitats in the Arctic and Antarctic. The ability to fix atmospheric N2can provide an advantage in nitrogen-poor environments. Nostoc also has the ability to screen damaging ultraviolet light in terrestrial and shallow benthic habitats. The genus potentially could be important in paddy rice culture because it fixes nitrogen that may later be released and used by plants; it also may play a role in soil formation and may increase nitrogen input to natural aquatic and terrestrial ecosystems. The abilities to survive in terrestrial habitats and fix N2are important in symbiotic interactions with fungi (lichens), liverworts, hornworts, mosses, ferns, cycads, and the angiosperm Gunnera. Nostoc is somewhat resistant to predation; this probably is related to production of large amounts of sheath material, synthesis of microcystin-like toxins by some strains, and formation of colonies that are too large for many algivores to consume. Some organisms can subsist on Nostoc, although it may not be a preferred food source. Lytic cyanophages also infect Nostoc, but little is known about population control of Nostoc in its natural environment, Late Precambrian fossils resembling Nostoc have been described, and Nostoc possibly has been an important component of many terrestrial and aquatic communities since that time.

Ultraviolet laser system and method for forming vias in multi-layered targets

Abstract: The output of a continuously pumped, Q-switched, Nd:YAG laser (10) is frequency converted to provide ultraviolet light (62) for forming vias (72, 74) in multi-layered targets (40). The parameters of the output pulses (62) are selected to facilitate substantially clean, simultaneous or sequential drilling or via formation in a wide variety of materials such as metals, organic dielectrics, and reinforcement materials having different thermal absorption characteristics in response to ultraviolet light. These parameters typically include at least two of the following criteria: high average power of greater than about 100 milliwatts measured over the beam spot area, a temporal pulse width shorter than about 100 nanoseconds, a spot diameter of less than about 50 microns, and a repetition rate of greater than about one kilohertz. The laser system (10) and method circumvent conventional depth of cut saturation limitations and can achieve an increased depth of cut per pulse in a target (40) formed of either single- or multi-layered material.

Evidence of an association between non-Hodgkin's lymphoma and skin cancer.

Abstract: OBJECTIVE--To investigate a possible link between exposure to ultraviolet light and the almost epidemic increase in non-Hodgkin's lymphoma worldwide. Because ultraviolet light is known to cause skin cancers, the association between non-Hodgkin's lymphoma and skin cancer was studied. DESIGN--Secondary occurrence of either malignant melanoma or squamous cell skin cancer in cohorts of patients with a first diagnosis of either non-Hodgkin's lymphoma or chronic lymphocytic leukaemia, and vice versa, were studied. Expected numbers of subsequent cancers were calculated by sex, age, and period specific national incidence rates multiplied by the person years under observation in the cohorts. SETTING--Denmark (1943-89) and Sweden (1958-89). SUBJECTS--Four population based cohorts identified in the nationwide cancer registries (34,641 people with non-Hodgkin's lymphoma, 17,400 with chronic lymphocytic leukaemia, 34,989 with malignant melanoma, 25,980 with squamous cell skin cancer). A total of 562,085 person years were accrued for the analysis. MAIN OUTCOME MEASURES--The ratios of observed to expected cancers (the standardised incidence ratio) served as a measure of the relative risk. RESULTS--The relative risk for developing squamous cell skin cancer was 5.5 (95% confidence interval 4.6 to 6.6) among patients with non-Hodgkin's lymphoma and 8.6 (7.2 to 10.3) among patients with chronic lymphocytic leukaemia. The relative risks remained high over more than 15 years of follow up. Relative risks for malignant melanoma were 2.4 (1.8 to 3.2) for patients with non-Hodgkin's lymphoma and 3.1 (2.1 to 4.4) for patients with chronic lymphocytic leukaemia. After squamous cell skin cancer had been diagnosed there was a twofold excess risk for non-Hodgkin's lymphoma and chronic lymphocytic leukaemia. By contrast, in each of the cohorts the general cancer risks excluding skin and lymphoproliferative malignancies were close to the expected. CONCLUSIONS--The occurrence of non-Hodgkin's lymphoma and skin cancer are strongly associated; this supports the hypothesis that the secular increase in exposure to ultraviolet light may have contributed to the increasing incidence of non-Hodgkin's lymphoma in recent decades.

Heat shock protein 70 overexpression affects the response to ultraviolet light in murine fibroblasts. Evidence for increased cell viability and suppression of cytokine release.

Abstract: To elucidate cellular concepts for protection against ultraviolet (UV) light we investigated the effect of heat shock protein 70 (hsp70) overexpression on cell viability and on the secretion of UV-inducible immunological cytokines. Transfected murine fibrosarcoma cells (WEHI-S), overexpressing hsp70 or a sham transfected control were used. Overexpression of hsp70 was sufficient to markedly increase cell viability upon treatment with UVB (290-320 nm). Since long wave UV (UVA, 320-400 nm) as well as UVB turned out to stimulate the release of O2- radicals we studied the cell viability upon oxidative stress. Hsp70 overexpression increased viability upon treatment with hydrogen peroxide or menadione, but had no influence on UV-induced O2- release. UV-light is known to upregulate immunologic and proinflammatory cytokines such as IL-1 and IL-6. Oxidative stress appeared to exert a similar effect. Hsp70 overexpression markedly decreased the release of IL-6 induced by UVA, UVB and oxidative stress. To test whether the hsp70 mediated suppression is confined to events caused by UV-light we determined IL-1-mediated effects. IL-1-induced IL-6 release was reduced by hsp70 overexpression, whereas the IL-1 mediated activation of nuclear factor kappa B was not affected. Our data suggests that hsp70 plays a central role not only in cell protection against UV-light, but also in the regulation of proinflammatory cytokine release induced by UV-exposure.

Antioxidant activity of allicin, an active principle in garlic

Abstract: Garlic has been claimed to be effective against diseases, in the pathophysiology of which oxygen free radicals (OFRs) have been implicated. Effectiveness of garlic could be due to its ability to scavenge OFRs. However, its antioxidant activity is not known. We investigated the ability of allicin (active ingredient of garlic) contained in the commercial preparation Garlicin to scavenge hydroxyl radicals (·OH) using high pressure liquid chromatographic (HPLC) method. ·OH was generated by photolysis of H2O2 (1.25–10 μmoles/ml) with ultraviolet light and was trapped with salicylic acid which is hydroxylated to produce ·OH adduct products 2,3- and 2,5-dihydroxybenzoic acid (DHBA). H2O2 produced a concentration-dependent ·OH as estimated by ·OH adduct products 2,3-DHBA and 2,5-DHBA. Allicin equivalent in Garlicin (1.8, 3.6, 7.2, 14.4, 21.6, 28.8 and 36 μg) produced concentration-dependent decreases in the formation of 2,3-DHBA and 2,5-DHBA. The inhibition of formation of 2,3-DHBA and 2,5-DHBA with 1.8 μg/ml was 32.36% and 43.2% respectively while with 36.0 μg/ml the inhibition was approximately 94.0% and 90.0% respectively. The decrease in ·OH adduct products was due to scavenging of ·OH and not by scavenging of formed ·OH adduct products. Allicin prevented the lipid peroxidation of liver homogenate in a concentration-dependent manner. These results suggest that allicin scavenges ·OH and Garlicin has antioxidant activity.

Chemical oxidation by photolytic decomposition of hydrogen peroxide.

Abstract: This paper describes a study of a chemical oxidation process involving simultaneous application of hydrogen peroxide solution and ultraviolet light (H 2 O 2 /UV)for removal of organic pollutants from aqueous solution. The process was investigated experimentally in a continuous-flow stirred tank reactor (CSTR) under various operational conditions, i.e., H 2 O 2 dosage, UV light intensity, and liquid residence time. Synthetic solutions of a model organic compound, n-chlorobutane (BuCI), were oxidized at various pH and in the presence of various amounts of humic material and carbonate/bicarbonate ions in order to examine the effect of water quality on the process efficiency. A kinetic model of the process, which was developed based on H 2 O 2 /UV-induced radical oxidation of organic compounds, was successfully verified in pure water as well as in synthetic solutions.

Neurofibrillary tangles in Niemann—Pick disease type C

Abstract: Post-mortem neuropathological examination of five cases of Niemann-Pick disease type C revealed neurofibrillary tangles in many parts of the brain. Tangles were a consistent finding in the hippocampus, hypothalamus, substantia innominata, midbrain pons and medulla. Other regions of the brain in which tangles were present included neocortex, basal ganglia, thalamus, cerebellar cortex in one case, and dentate nucleus in another. The tangles were argyrophilic, fluoresced under ultraviolet light when stained with thioflavin S, and reacted strongly with antibody to tau protein. Some of the tangles could be immunostained for ubiquitin. Electron microscopy, performed in one of the cases, showed the tangles to consist of paired helical filaments ultrastructurally identical to those of Alzheimer's disease. The distribution of the tangles in the central nervous system as a whole and also within many individual neurons corresponded fairly closely with that of the abnormal storage material. Both the tangles and the storage material extended into, and distended, the proximal parts of many dendrites and axons. No A4/beta protein, either in the form of plaques or in the walls of blood vessels, was detected in any of the cases. Our findings suggest that neurofibrillary tangles are a common feature of Niemann-Pick disease type C and that their formation may be a reaction to the abnormal storage material.

Requirement for tyrosine phosphorylation of Cdk4 in Gl arrest induced by ultraviolet irradiation

Abstract: Exposure to ultraviolet light arrests the function of mammalian fibroblasts in the G1 phase of the cell cycle, as well as the S and G2 phases. Although p21, an inhibitor of cyclin-dependent kinase (Cdk) that is induced by DNA damage may partly account for the arrest in G1 (ref. 1), the mechanism is little understood. Here we show that tyrosine phosphorylation of Cdk4 is required for this arrest. In rat fibroblast, Cdk4 is tyrosine-phosphorylated during G1 progression, and its dephosphorylation is required for S phase. When cells are ultraviolet-irradiated, their arrest in G1 is accompanied by an increase in phosphorylation level. Conversely, cells expressing unphosphorylatable Cdk4F17 fail to arrest in G1, and suffer significantly elevated chromosomal aberrations and cell death.

Cutaneous Melanoma in Women I. Exposure to Sunlight, Ability to Tan, and Other Risk Factors Related to Ultraviolet Light

Abstract: A population-based case-control study of cutaneous malignant melanoma (CMM) was conducted in 452 women with melanoma and 930 control subjects aged 25-59 years in five San Francisco Bay Area counties between 1981 and 1986. Women were interviewed in their homes with regard to history of sunlight exposure and sunburns during different periods in their lives, phenotypic and host characteristics, medical history, occupation, and demographic factors. Data were analyzed by the patients' histologic type of melanoma; 355 women were classified as having superficial spreading melanoma (SSM), 61 had nodular melanoma (NM), 13 had lentigo maligna melanoma, and 23 had other melanomas that could not be further classified upon histologic review by University of California dermatopathologists. Univariate results from analysis of factors related to sun exposure showed that the risk of all histologic types of CMM, SSM, and NM increased with increasing tendency of the subject to sunburn and with history of increased severity and/or frequency of sunburns up to age 12 years. Risk of all types of CMM and SSM also increased with increasing number of sunburns for all age groups and with lack of use of sunscreen. After adjustment for each other and for phenotypic factors, history of sunburn up to age 12 and lack of sunscreen use were the primary sun-related factors associated with an increased risk of all types of CMM and SSM, while tendency to sunburn when exposed to 1/2 hour of noontime sun and lack of use of sunscreen were related to NM. Although having frequent sunburns before age 12 and having severe sunburns before age 12 were both strongly associated with melanoma, having large numbers of sunburns during any time period from elementary school through age 30 years and having sunburns during the 10 years prior to diagnosis or interview were all associated with a doubling of risk for SSM after adjustment for other factors. These results suggest that the increased risk of melanoma related to sunburns is not confined to childhood sunburns. Maintenance of an all-year tan provided no protective effect against melanoma after adjustment for tendency to burn. No association was noted with use of fluorescent lights or exposure to sunlamps for all types of CMM, SSM, or NM.

Oxidation of gold by ultraviolet light and ozone at 25 °C

Abstract: Gold surfaces have been found to be hydrophilic only after exhaustive preparation and with the ultimate care in sample preparation and treatment. The use of a combination of ultraviolet (UV) light and ozone has been described as a viable method of producing a clean, hydrophilic, gold surface. We have found that gold surfaces, which have been either stored in the laboratory after vacuum deposition or purchased as high purity standards, are oxidized by a combination of UV light and ozone generated from a mercury lamp. The samples were characterized with x‐ray photoelectron spectroscopy (XPS) and ion scattering spectroscopy (ISS) prior to and after exposure to UV/ozone in a stainless steel box in laboratory air. After the cleaning process gold surfaces were found by XPS to contain less carbon and to be enriched in oxygen. The O 1s on the cleaned surface, which was not present on the untreated surface, consisted of two peaks that are attributed to gold oxide and hydroxyl. The oxide layer was found to be 17±4 A thick by variable angle XPS depth profiling with an initial stoichiometry of Au2O3. The oxide was found to be stable to extended exposure to UHV and water and ethanol rinses. ISS compositional depth profiles confirmed the oxide layer thickness and that the hydrated surface layer is removed in the initial sputtering of the oxidized gold. Implications of these results related to the mechanism of self‐assembly of thiols on gold are discussed.

The role of vitamin E in normal and damaged skin

Abstract: The generation of free oxygen radicals is believed to play an important pathogenic role in the development of various disorders. More than other tissues, the skin is exposed to numerous environmental chemical and physical agents such as ultraviolet light causing oxidative stress. In the skin this results in several short- and long-term adverse effects such as erythema, edema, skin thickening, wrinkling, and an increased incidence of skin cancer or precursor lesions. However, accelerated cutaneous aging under the influence of ultraviolet light, usually termed photoaging, is only one of the harmful effects of continual oxygen radical production in the skin. Others include cutaneous inflammation, autoimmunological processes, keratinization disturbances, and vasculitis. Vitamin E is the major naturally occurring lipid-soluble non-enzymatic antioxidant protecting skin from the adverse effects of oxidative stress including photoaging. Its chemistry and its physiological function as a major antioxidative and anti-inflammatory agent, in particular with respect to its photoprotective, antiphotoaging properties, are described by summarizing animal studies, in vivo tests on human skin and biochemical in vitro investigations. The possible therapeutic use in different cutaneous disorders, and pharmacological and toxicological aspects are discussed. Many studies document that vitamin E occupies a central position as a highly efficient antioxidant, thereby providing possibilities to decrease the frequency and severity of pathological events in the skin. For this purpose increased efforts in developing appropriate systemic and local pharmacological preparations of vitamin E are required.

Xwnt-8b: a maternally expressed Xenopus Wnt gene with a potential role in establishing the dorsoventral axis

Abstract: In amphibian embryos, establishment of dorsal-ventral asymmetry is believed to involve dorsal-ventral differences in vegetally derived mesoderm-inducing signals and/or differences in the competence of animal hemisphere (ectodermal) cells to respond to these signals. Previous studies have shown that certain Wnt proteins can generate an ectopic dorsal axis when misexpressed, and that they do so by modifying the response of ectodermal cells to inducers. None of these Wnt proteins are expressed at an appropriate time to do so in vivo. In this study, we describe the isolation and characterization of a full length cDNA for the Xenopus Wnt gene, Xwnt-8b, whose biological activity and expression pattern suggest that it may be involved in establishment of the dorsoventral axis. Both maternal and zygotic Xwnt-8b transcripts undergo alternative splicing to generate mRNAs which encode two different forms of Xwnt-8b protein. During early cleavage stages Xwnt-8b transcripts are confined primarily to animal hemisphere blastomeres, while zygotically derived Xwnt-8b transcripts are restricted almost exclusively to a band of cells in the prospective forebrain of neurula and tailbud stage embryos. Ectopically expressed Xwnt-8b can completely rescue dorsal development of embryos ventralized by exposure to ultraviolet light, and can induce a complete secondary axis in wild-type embryos. Axis induction is observed only if Xwnt-8b is supplied prior to the onset of zygotic gene transcription. This biological activity, together with the presence of maternal Xwnt-8b transcripts in cells that will be induced to form the dorsal mesoderm, is consistent with the possibility that Xwnt-8b may be the endogenous agent that establishes asymmetry in the response of ectodermal cells to mesoderm-inducing signals, thereby initiating dorsal development.

Industrial waste water treatment

Abstract: A waste water treatment system is illustrated which can be configured to be portable and which minimizes the addition of solids to be disposed of through the use of ozone for contaminant reduction to basic elements after the pH value of the waste water to be treated is properly adjusted. This ozone in one stage is combined with ultrasound to cause coagulation and precipitation. In another stage, ozone and ultraviolet light are used in a reduction process. Ion alignment using a magnetic field and an electrochemical flocculation process to which the waste water is subjected causes further coagulation and precipitation. As designed, the system can operate continuously with redundancy at appropriate points so that removal of solids from the filtration units can occur simultaneous with the overall decontamination process.

Apodisation of the spectral response of fibre Bragg gratings using a phase mask with variable diffraction efficiency

Abstract: Bragg gratings with sidelobe levels 26 dB lower than the peak reflectivity have been fabricated in standard telecommunication optical fibres by exposure to ultraviolet light through a phase mask with a locally varying diffraction efficiency This represents a reduction of 14 dB in the sidelobe levels compared to uniform gratings with the same bandwidth and reflectivity

UV and ozone treatment of polypropylene and poly(ethylene terephthalate)

Abstract: The effects of exposure to ultraviolet (UV) light and ozone, separately and in combination, were investigated with respect to polypropylene (PP) and poly(ethylene terephthalate) (PET) surfaces. Three combinations of UV light and ozone were studied: ozone only, UV light in air (producing ozone), and UV light in air (producing ozone) supplemented by additional ozone in the incoming air. The effect of the exposure time of the PP and PET to each treatment was studied. The samples were analyzed by X-ray photoelectron spectroscopy (XPS) to determine the surface composition, and by dynamic contact angle to determine the water wettability. The results showed that the effect of the treament was dependent on the properties of the exposed polymer, with PET being more sensitive to the UV light and PP being more sensitive to the reactive species in the gas. The exposure times studied ranged from 1 to 90 min. By monitoring the oxygen uptake levels, we were able to determine that surface modification occurred within min...

CDKN2 (MTS1) tumor suppressor gene mutations in human tumor cell lines.

Abstract: Tumor suppressor gene CDKN2 (also called MTS1, CDK4I and p16INK4) is located in 9p21 and deleted homozygously in a high percentage of tumor cell lines. We have examined the sequence of CDKN2 in 154 tumor cell lines that are not homozygously deleted for CDKN2. Overall, 18% (27/154) of the cell lines carried mutations in CDKN2. These mutations were found in cell lines derived from melanoma, bladder, lung and prostate cancers, as well as sarcomas of various origin. The spectrum of the CDKN2 mutations found in melanoma cell lines indicated a major role for ultraviolet light in generating the mutations, suggesting the mutations occurred in vivo. The frequency of loss of heterozygosity in 9p21 in this set of lines is only slightly higher than the background rate of aneuploidy, suggesting that a second 9p21 tumor suppressor gene, if it exists, must lie near CDKN2.

Adenovirus-mediated heme oxygenase-1 gene transfer into rabbit ocular tissues.

Abstract: Purpose. Heme oxygenase-1 (HO-1) is a stress protein induced up to 100-fold within a few hours after exposure to oxidative stress, and it has been shown to counteract oxidative injury induced by ultraviolet light or free radicals. The current study was undertaken to determine whether the HO-1 gene can be introduced into adult rabbit ocular tissues by microinjection of a recombinant replication-deficient adenovirus human HO-1 cDNA (Adv-HHO). Methods. Human HO-1 gene was used for transfection studies to differentiate endogenous from transfected HO. The purified Adv-HHO construct (10 8 pfu/ml) was mixed with lipofectamine and microinjected into the anterior chamber, vitreous cavity, and subretinal space of New Zealand rabbit eyes. After 2 weeks, total RNA was extracted from different ocular tissues, reverse transcription-polymerase chain reaction was performed using specific human HO-1 primers, and amplification products were subjected to Southern hybridization. Results. Transfection with the Adv-HHO construct into rabbit corneal epithelial cells in culture resulted in a functional expression of the human HO-1 gene ; the human HO-1 mRNA was detected, and enzyme activity increased threefold. Human HO-1 mRNA was detected in the retina after microinjection of the Adv-HHO construct into the subretinal space. Microinjection into the vitreous resulted in HO-1 mRNA expression in the corneal endothelium, iris, lens, and retina ; after intracameral injection of the Adv-HHO construct, human HO-1 mRNA was detected in corneal epithelium and endothelium, ciliary body, lens, and iris. Regardless of the injection site, transfected human HO-1 mRNA was undetectable in tissues outside the eye, that is, brain, liver, and kidney. Conclusions. These results demonstrated a tissue-selective functional transfer of the human HO-1 gene into rabbit ocular tissues in vivo. This technique may be a promising means for delivering HO-1 gene in vivo as a protective mechanism against oxidative stress that contributes to the pathogenesis of ocular diseases such as cataract, light-induced injury, age-related macular degeneration, and diabetic retinopathy. Invest Ophthalmol Vis Sci. 1995 ;36 :2202-2210.

Particle‐associated coliform in secondary effluents: shielding from ultraviolet light disinfection

Abstract: In this research, the effectiveness of various blending and sonication techniques were investigated for extracting particle-associated coliforms from secondary effluent samples. The amount of shielding from ultraviolet disinfection afforded these coliforms by the particulates was then assessed. It was found that blending samples for 1.5 minutes at 19 000 rpm at 4°C in a mixture of chemicals (resulting in concentrations of 10 -6 M Zwittergent 3-12, 10 -3 M EGTA, 0.01 M Tris buffer, 0.1% peptone, and pH 7) resulted in the greatest recovery of particle-associated coliform, as detected by the multiple tube fermentation (MTF) test. Fragmentation of large flocs during homogenization, as evidenced by the change in particle size distribution, was most likely the responsible mechanism. Sonication proved ineffective. It was found that particle association and shielding of coliforms significantly affect accurate measurements of coliform density in secondary effluent using the standard MTF test and that significantly more coliforms may be present in disinfected secondary effluents than is indicated by the standard enumeration procedure.