Molteno implantation for glaucoma in young patients

Seventy patients younger than 21 years of age underwent Molteno implantation for nonneovascular glaucoma. Fifty-three (76%) patients had failed angle and/or conventional filtering surgery. Final intraocular pressure less than 22 mmHg (but over 5 mmHg) was achieved in 40 (62%) of the 65 patients with at least 6-month follow-up (range, 6 to 59 months; mean +/- standard deviation, 22.7 +/- 14.1 months); however, only 22 (34%) were controlled after the initial Molteno implantation procedure, and 54 (83%) patients underwent further glaucoma and/or nonglaucoma surgical procedures. The visual acuities remained within one line of their preoperative levels or improved in 25 (68%) of the 37 patients on whom Snellen acuities were available. The most frequent complications included: tube-cornea touch (20%, transient in 3%), corneal edema (17%), retinal detachment (16%), tube block (10%), cataract (9%), chronic hypotony or phthisis (9%), pupillary or cyclitic membrane (9%), hyphema (7%), flat anterior chamber (6%), and large postoperative choroidal effusion (6%). Despite the high rates of subsequent surgical interventions and complications, Molteno implantation has been a useful approach for achieving intraocular pressure reduction in young patients with glucoma.

Laser trabecular ablation (LTA)

As part of a pilot study for glaucoma surgery, the use of 3 infrared solid state lasers with 4 fiber optic delivery systems to ablate human trabecular meshwork was investigated. Laser trabecular ablation (LTA) was attempted with the Erbium:YAG (2.94 microns), Erbium:YSGG (2.79 microns), and Holmium:YSGG (2.1 microns) lasers. Laser energy was delivered as a single pulse (250 microseconds) by tissue fiber optic contact with low hydroxyl-fused silica (200 and 500 microns), zirconium fluoride (250 microns), or sapphire (250 microns) fiber optics. Total energy required and thermal effects decreased as laser wavelength increased. LTA was best achieved at 2.94 microns (4 mJ total energy; energy densities = 8.2-12.7 J/cm2; pulse length 250 microseconds) with average thermal damage zones of 5.3-10.3 +/- 1.3-2.4 microns (means +/- SDs) to contiguous structures. This finding has potential applications in the surgical treatment of open-angle and congenital glaucoma and may minimize failure rates seen in other types of surgery on the trabecular meshwork where disrupted trabecular meshwork is not removed.

Use of a symblepharon ring for treatment of over-filtration and leaking blebs after glaucoma filtration surgery

We report the use of a symblepharon ring in the treatment of seven cases of flat anterior chamber (six cases of total iridocorneal touch, and one of corneallens touch) secondary to overfiltration or to bleb leak. In all cases, the anterior chamber reformed within 24 hours after the symblepharon ring was used. Advantages of using the ring are: (a) it permits testing of visual acuity, tonometry, and intraocular examination without removing it; (b) it does not require suturing to the conjunctiva; (c) it does not disturb the corneal epithelium; (d) it may be available at institutions lacking other shells; and (e) it is cost-effective.

Eosinophils and mast cell homogeneity of the guinea pig eyelid skin, conjunctiva, and ileum

Mast cell heterogeneity has been described on the basis of differential staining reactions, light microscopic morphology, anatomic location, degranulation after polyamines, biochemical contents, growth requirements, and reactions to lymphokines. We have demonstrated typical "connective-tissue mast cells" by using anatomic criteria, histological staining reactions, electron microscopy, and reaction to compound 48/80 in the guinea pig conjunctiva, eyelid skin, and ileum. A second, much larger population of cells in the ileal mucosa and the conjunctiva, and rarely in the eyelid skin stained reddish-blue with acid toluidine blue in tissue fixed in ethanol-acetate-lead subacetate (BLA) and with alkaline Giemsa in formaldehyde-fixed tissue, did not stain with ethanolic or acid toluidine blue in formaldehyde-fixed tissue or with alkaline Giemsa in BLA-fixed tissue, and did not degranulate after 48/80 treatment. These are features of the rat intestinal "mucosal mast cells"; however, ultrastructural and light microscopic studies with the orcein Giemsa stain demonstrated these cells in the guinea pig to be eosinophils. Tissue culture, biochemical, and immunological studies indicate the existence of a second type of mast cell (bone-marrow-derived mast cell), ultrastructurally almost indistinguishable from the connective tissue mast cell. Our studies demonstrate only one mast cell type in the guinea pig and support the contention that other forms of mast cells are immature forms or variants of the connective-tissue mast cell.

Asthma, wheezing, and school absence in primary schools

The prevalence of wheezing, 'asthma', treatment for 'asthma', and school absence as a result of wheezing in Nottingham was calculated from a questionnaire survey of parents of 4750 children in a random sample of primary schools. A response was achieved for 3805 (80%) children of whom 438 (11.5%) had had episodes of wheezing in the last year and 224 (5.9%) had been diagnosed as having asthma. Asthma treatment had been prescribed for 251 (6.6%) of all children, two thirds of all the children receiving drugs. Two hundred and sixty five (7%) children had lost time from school because of wheezing (median loss of seven days). Of the 64 children losing more than 10 days, 45 (70%) were not taking any drugs, or taking only beta agonists. The prevalence of wheezing found by this survey was comparable with that in similarly designed surveys, though the proportion of children diagnosed as having asthma was higher. Though doctors may now diagnose asthma more readily wheezing still remains an important cause of school absence and still seems to be undertreated.

Emphysematous pyelonephritis

Images

Correlation of afferent pupillary defect with visual field loss on automated perimetry

The study was designed to ascertain the relationship between visual loss in the central 30 degrees of vision and the density of the relative afferent pupillary defect (APD). The APD of 26 patients was quantified using a neutral log density filter. The mean threshold light sensitivity on Humphrey automated perimetry (Program 30-1) of one eye was substracted from the fellow eye total to yield the interocular visual field difference (VFD). A direct correlation was noted such that the log density of the APD increased linearly with an increase in VFD (r = 0.69, P = 0.0001). In the absence of ptosis or ocular media opacification, a VFD greater than 8.7 that is not associated with an APD is suggestive of functional visual loss. Four patients had an APD despite normal static automated perimetry, indicating that an APD may be one of the earliest signs of retinal ganglion cell or axonal dysfunction.

Use of a "sandwich" technique to control image geometry in clinical studies comparing intraoral xeroradiographs and E-speed films

A method of superimposing a film on a xeroradiographic (XR) cassette for simultaneous intraoral exposure is evaluated for use as an imaging technique in clinical studies comparing Ektaspeed film and XR images. Sandwich images were indistinguishable from those produced by conventional technique. Pilot studies were conducted with 104 patients who had symptomatic dental problems. No significant differences were found in diagnostic usefulness or image quality between XR and film radiographs when sign test analysis was used. The sandwich technique yielded film and XR images with duplicate image geometry while reducing patient exposures to one half of that used in conventional image comparison protocols.

Identification of O-methylsterigmatocystin as an aflatoxin B1 and G1 precursor in Aspergillus parasiticus

An isolate of Aspergillus parasiticus CP461 (SRRC 2043) produced no detectable aflatoxins, but accumulated O-methylsterigmatocystin (OMST). When sterigmatocystin (ST) was fed to this isolate in a low-sugar medium, there was an increase in the accumulation of OMST, without aflatoxin synthesis. When radiolabeled [14C]OMST was fed to resting mycelia of a non-aflatoxin-, non-ST-, and non-OMST-producing mutant of A. parasiticus AVN-1 (SRRC 163), 14C-labeled aflatoxins B1 and G1 were produced; 10 nmol of OMST produced 7.8 nmol of B1 and 1.0 nmol of G1, while 10 nmol of ST produced 6.4 nmol of B1 and 0.6 nmol of G1. A time course study of aflatoxin synthesis in ST feeding experiments with AVN-1 revealed that OMST is synthesized by the mold during the onset of aflatoxin synthesis. The total amount of aflatoxins recovered from OMST feeding experiments was higher than from experiments in which ST was fed to the resting mycelia. These results suggest that OMST is a true metabolite in the aflatoxin biosynthetic pathway between sterigmatocystin and aflatoxins B1 and G1 and is not a shunt metabolite, as thought previously.

Management of asthma in schools

A questionnaire on asthma in schools was circulated to 291 Nottingham schools. The response rate was 91%. Three areas of concern were identified: are schools aware of all their asthmatic pupils; should children have more access to their medications in school; and do teachers need more guidance in supervising illnesses.

Color mutants of Aspergillus flavus and Aspergillus parasiticus in a study of preharvest invasion of peanuts

A comparison of the invasion of flowers, aerial pegs, and kernels by wild-type and mutant strains of Aspergillus flavus or A. parasiticus along with aflatoxin analyses of kernels from different drought treatments have supported the hypothesis that preharvest contamination with aflatoxin originates mainly from the soil. Evidence in support of soil invasion as opposed to aerial invasion was the following. A greater percentage of invasion of kernels rather than flower or aerial pegs by either wild-type A. flavus or mutants. Significant invasion by an A. parasiticus color mutant occurred only in peanuts from soil supplemented with the mutant, whereas adjacent plants in close proximity but in untreated soil were only invaded by wild-type A. flavus or A. parasiticus. Aflatoxin data from drought-stressed, visibly undamaged peanut kernels showed that samples from soil not supplemented with a mutant strain contained a preponderance of aflatoxin B's (from wild-type A. flavus) whereas adjacent samples from mutant-supplemented soil contained a preponderance of B's plus G's (from wild-type and mutant A. parasiticus). Preliminary data from two air samplings showed an absence of propagules of A. flavus or A. parasiticus in air around the experimental facility.

Mean geocarposphere temperatures that induce preharvest aflatoxin contamination of peanuts under drought stress

Apparently undamaged peanuts grown under environmental stress in the form of drought and heat become contaminated with Aspergillus flavus and aflatoxin in the soil prior to harvest. The upper mean temperature limit for aflatoxin contamination in undamaged peanut kernels grown under drought stress the latter 4-6 weeks of the growing season was between 29.6-31.3 degrees C. The lower limit was between 25.7-26.3 degrees C. That is, peanuts grown under drought stress with a mean geocarposphere temperature of 29.6 degrees C were highly contaminated while those at 31.3 degrees C were not contaminated. Likewise, those grown under drought stress with a mean geocarposphere temperature of 25.7 degrees C were not contaminated while those subjected to a mean geocarposphere temperature of 26.0 degrees C resulted in some categories becoming contaminated. Increasing the mean temperature up to 29.6 degrees C caused increasing amounts of contamination.

Bioavailability studies with ciglitazone in beagles. I. Effect of a meal on the bioavailability of three ciglitazone dosage forms

Three separate Latin square crossover studies were conducted in beagles to examine the effect of a meal on the bioavailability of a ciglitazone tablet, suspension, and solution. In these studies, drug was administered to fasted animals with either 50 ml water or with 180 g Purina Dog Chow and 20 g butter. The data indicated that the meal significantly increased the AUC by about 40 per cent for both the tablet and the suspension but had no significant effect on the solution treatment. Comparisons across studies indicated low bioavailability in fasted animals from either the tablet or suspension relative to the solution. When drug was co-administered with a meal, however, bioavailability appeared to be independent of dosage form.

Effect of soil temperature and drought on peanut pod and stem temperatures relative to Aspergillus flavus invasion and aflatoxin contamination

Peanut stem and pod temperatures of plants growing in irrigated, drought, drought-heated soil, and drought-cooled soil treatments were determined near the end of the growing season. Mean soil temperatures of the treatments during this period were 21.5 degrees, 25.5 degrees, 30 degrees and 20 degrees C, respectively. Peanut stem temperatures in all drought treatments reached a maximum of ca. 40 degrees C and for 6-7 h each day were as much as 10 degrees C warmer than irrigated peanut stems. Pod temperatures in drought-heated soil and drought treatments were ca. 34 degrees C and 30 degrees C, respectively, for several hours each day. As pod temperatures approached the optimum for A. flavus growth (ca. 35 degrees C), the proportion of kernels colonized and aflatoxin concentrations increased. Increased plant temperature without accompanying pod temperature increases (drought-cooled soil) resulted in colonization percentages and aflatoxin concentrations only slightly higher than those of the irrigated peanuts.

Effect of geocarposphere temperature on pre-harvest colonization of drought-stressed peanuts by Aspergillus flavus and subsequent aflatoxin contamination

Florunner peanuts grown in research plots were subjected to 5 soil temperature and moisture treatment regimes resulting in A. flavus infestation and subsequent aflatoxin contamination in drought-stressed peanuts. Treatments imposed beginning 85 days after planting were drought, drought with heated soil and 3 drought treatments with cooled soil. The incidence of A. flavus in drought-stressed, unshelled , sound mature kernels ( SMK ) decreased with decreases in the mean 5 cm deep soil temperature. The incidence of A. flavus was greater in inedible categories and in damaged kernels than in SMK . The mean, threshold, geocarposphere temperature required for aflatoxin development during the latter part of the peanut growth cycle was found to be between 25.7 degrees C and 27 degrees C.

Viable fungi in corn dust

Numbers of viable fungal propagules in corn dusts in southern Georgia were estimated during various farm and grain elevator operations in 1979, 1980, and 1982. A six-stage Andersen sampler for viable microbial particles was used to sample the dusts with various agar media. The most abundant fungi in corn dusts were species of yeasts: Aspergillus, Penicillium, Cladosporium, Alternaria. Helminthosporium, and Fusarium. However, the relative abundance of these fungi differed between years. There was a greater incidence of the Aspergillus flavus group in the hot, dry year of 1980 compared with the cooler, wetter years of 1979 and 1982. Fungi in the corn dusts sampled numbered between 10(4) and 10(9) viable propagules per m3 of air. By contrast, outdoor air often contained fewer than 10(4) viable fungal propagules per m3. Most A. flavus propagules were deposited at stages three and four of the Andersen sampler, with correspond to the trachea, primary bronchi, and secondary bronchi in the human respiratory system. In an assessment of the air spores by exposing sterile petri dishes, more large-spored fungi, like Alternaria tenuis, and fewer small-spored fungi, such as A. flavus, were detected when compared with colony counts from petri dishes exposed to air in the Anderson sampler.

Optical Stark effects on pure-spin Raman transitions in molecular oxygen

Fully resolved pure-spin Raman transitions near 2 cm(-1) have been observed in (3)Sigma(g) ground-state molecular oxygen using stimulated Raman techniques. Anomalous differences between polarized and depolarized spectra are fully explained in terms of optical Stark effects.

Effects of soil moisture and temperature on preharvest invasion of peanuts by the Aspergillus flavus group and subsequent aflatoxin development

Four soil temperature and moisture treatment regimens were imposed on Florunner peanuts 94 days after planting in experimental plots in 1980. At harvest (145 days after planting), the incidence of the Aspergillus flavus group and the aflatoxin concentration were greatest in damaged kernels. Extensive colonization of sound mature kernels (SMK) by the A. flavus group occurred with the drought stress treatment (56% kernels colonized); colonization was less in the irrigated plot (7%) and the drought stress plot with cooled soil (11%) and was intermediate in the irrigated plot with heated soil (26%). Aflatoxin was virtually absent from SMK with the last three treatments, but it was found at an average concentration of 244 ppb (ng/g) in drought-stressed SMK. Colonization of SMK by the A. flavus group and aflatoxin production were greater with hot dry conditions. Neither elevated temperature alone nor drought stress alone caused aflatoxin contamination in SMK. When the ratio of SMK colonized by A. flavus compared with A. niger was greater than 19:1, there was aflatoxin contamination, but there was none if this ratio was less than 9:1. Irrigation caused a higher incidence of A. niger than drought did. This may have prevented the aflatoxin contamination of undamaged peanuts.

Isolation of Citreoviridin from Penicillium charlesii Cultures and Molded Pecan Fragments

The extraction and systematic fractionation of Penicillium charlesii Smith cultures and contaminated pecan fragments yielded the yellow mycotoxin citreoviridin. Citreoviridin proved acutely toxic to 1-day-old chickens, with an oral 50% lethal dose of 37.5 mg/kg, and showed plant growth inhibition in wheat coleoptiles even at concentrations as low as 10 −4 M. It was toxic to corn seedlings but did not affect young tobacco seedlings.

Ignition-delay times in laser initiated combustion

A single pulse from a TEA CO(2) laser is used to heat 1:7:14 mixtures of SF(6):CH(4):O(2) to temperatures near 1000 K. A short- or long-duration pulse (one-half the energy deposited in 0.25 or 0.82 microsec, respectively) from a second TEA CO(2) laser is used to ignite the mixture. At comparable values of absorbed energy from the second laser, ignition-delay times for the long-duration secondary pulse are approximately twice those for the short-duration pulse. Ignition of the hot mixture requires about 10% less absorbed energy with the short-duration pulse than with the long-duration pulse. These results indicate the short-duration pulse is more effective in producing a high population density of reactive species that initiate the reactions necessary for ignition.

Holographic interferometry of a large-bore cw high-energy gas-laser medium during laser-power extraction

A holographic interferometer is described that is used in conjunction with a high-speed camera system (10,000 frames/sec) to record the temporal and spatial interactions of the laser gas medium and the resonator mode. In particular, a high-power CO(2) electric discharge convectively cooled laser-gas medium was interferometrically analyzed before, during, and after laser power extraction such that the mode-medium interaction was observed.

Pulsed spontaneous Raman scattering technique for luminous environments

A gated photon counting system, cavity-dumped argon-ion laser, and a multipass retroreflecting light cell have been combined in a system to enhance spontaneous Raman scattering in luminous background situations. Signal-to-background ratio (SBR) has been improved a factor of 450 over a single-pass cw system with cw power equal to the pulsed average power. The improvement attributable to the gating and cavity dumping the laser is a factor of 30. A factor of 15 improvement is due to the retroreflecting light cell. Temperature and density data obtained from N(2)Q-branch spectra of a luminous methane-air flame are presented to illustrate the utility of the system. A passband fitting technique is introduced to analyze the data.

Retroreflecting multipass cell for Raman scattering

A retroreflecting multipass cell consisting of two lenses and both on-axis and off-axis retroreflecting mirror assemblies has been constructed and tested. A gain in Raman scattered signal intensity of 20 has been attained in a focal volume 1.1 mm x 0.3 mm x 0.3 mm. A system employing off-axis paraboloids should provide somewhat higher gain and a diffraction limited focal volume. These systems are applicable to Raman diagnostics of various gas dynamic processes, including flame gases, or the characterization of the gas mixing process in gas-dynamic or chemical laser nozzle arrays.

Focused, multiple-pass cell for Raman scattering

A simple optical system is described that makes use of a unique property of ellipsoidal mirrors, viz., light brought to one focus will be reflected alternately through the two foci and collapse to the major axis. This system consists of an on-axis ellipsoidal mirror facing a coaxial flat-spherical mirror assembly that is positioned at the minor axis. Calculations indicate that gains of the order of 500 in the light flux at the point of observation should be attainable with low-eccentricity ellipsoids. Raman-scattered light from atmospheric N(2) was obtained with a system employing a 0.2 eccentricity ellipsoid. An experimental gain of 93 was determined by the ratio of the scattering with the system to the scattering obtained with one beam. This result is in good agreement with the theory.

Method for measuring Doppler shifts in arc-heated flows

A novel method of determining both the Doppler and Stark shifts in a single measurement of spectral lines emitted by the arc-heated flow from a plasma jet has been successfully demonstrated. The method uses a spherical mirror arranged with its optical axis coincident with the optical axis of a Fabry-Perot interferometer and with its center of curvature at the center line of the flow. The common optical axis lies at an angle to the flow. With this system, both red-and blue-shifted line profiles are recorded in the same spectral scan. If conditions are such that the red-and blue-shifted profiles are not resolvable, the blue-shifted component is chopped so that the recorded signal consists of the envelopes of both the red-shifted profile and the superimposed red-and blue-shifted profiles. The wavelength difference between the blue-and red-shifted line profiles is exactly twice the Doppler shift integrated along a line of sight through the flow and is independent of a Stark shift. The Stark shift is given by the wavelength difference between the absolute line center and the midpoint of the red-and blue-shifted lines. Abel inversion of integrated line shift data has yielded radial velocity profiles to an accuracy of +/-3% in a supersonic, arc-heated argon flow.

A new plane grating monochromator with off-axis paraboloids and curved slits

A design for a new plane grating monochromator is described. The system employs a symmetrical configuration of off-axis paraboloids for both the collimator and camera mirrors. The entrance and exit slits are mounted on the same side of the grating and are curved in order to eliminate wavelength errors due to spectral line curvature. There is, in fact, a remarkable coincidence between the curvature which is required to avoid wavelength errors and the curvature which is required to obtain equal curvatures in the object and image planes. Ray tracing calculations for a symmetrical configuration of off-axis paraboloids show that the image of a curved slit with a length equal to 0.05 times the focal length of an f/5 mirror is diffraction limited for wavelengths lambda > 0.2 . micro.

Rapid scan spectrometers for the diagnostics of transient plasmas

An observation that a symmetrical configuration of off-axis paraboloidal mirrors produces an excellent image of an extended slit, while an unsymmetrical configuration produces poor images, has led to a modification of the original Sandia rapid scan spectrometer and to the design of a new wide range, rapid scan spectrometer. The new instrument employs a high speed rotating mirror in a Littrow arrangement to obtain a spectral scan speed double that of the original spectrometer; e.g., with a 600-lines/mm grating, a spectral scan speed of ~410 A/microsec is obtained at 1000 rps. Techniques for obtaining an accurate calibration of the spectral scan speed are described, and some examples of spectra which were recorded from a xenon and a hydrogen plasma are shown.

A dual recording, variable range, rapid-scan spectrometer; comparison of simultaneously recorded stark-broadened Halpha and Hbeta line profiles

An ultrarapid scanning spectrometer has been constructed that records spectra at a constant angle of diffraction. The spectral scanning is accomplished by the rotation of a high-speed rotating mirror (7.6 cm diam) that causes a collimated light beam to sweep across a plane grating, changing the angle of incidence. The full-aperture scanning range depends upon the over-all grating width, upon the grating spacing, and upon the orientation of the grating with respect to the high-speed mirror. For example, a 12.5-cm, 1200-lines/mm grating gives a scanning range of approximately 2000 A on each of two separate detector systems, or a total range of 4000 A that can be centered at any wavelength between 4000 A and 8000 A. This grating provides a theoretical resolving power of approximately 85,000 in the first order, a reciprocal dispersion of 17.5 A/mm at f/5, and a spectral scan speed of 115 A/microsec at 1100 rps. This spectrometer has been used to record, simultaneously, Stark-broadened Halpha and Hbeta emission line profiles from a transient plasma generated in the impulse tube. Electron densities calculated from the half-width of the Hbeta profiles are in good agreement with values obtained by fitting the line wings of the self-absorbed Halpha profiles to the theoretical profiles of Griem, Kolb, and Shen.