Microcycle conidiation and medusa head conidiophores of aspergilli on indoor construction materials and air filters from hospitals.

Microcycle conidiation and microniche colonization by aspergilli was observed in-situ on various indoor construction and finishing materials. Microcycle conidiation, direct conidiogenesis from a conidium or spore with minimal intervening hyphal development, for several decades has been considered a survival mechanism during stress for a variety of moulds. Adhesive transparent tape mounts and bulk materials from various indoor materials, including air filters from hospitals and healthcare institutions, were transported to the laboratory for light microscopic and scanning electron microscopic observations. Additional materials were held in moist chambers over nonsterile soils and examined periodically for fungal development. Microcycle conidiation was observed usually in areas of sparse fungal development, mostly in association with isolations of members of the Aspergillus flavus-, A. versicolor-, A. niger groups. Branched conidiophores and medusa heads, more often associated with colonization by Eurotium spp., were observed on some preserved woods. These conidiogenesis processes might be factors in the survival and blooms of indoor aspergilli.

Effects of anti-odor automobile air-conditioning system products on adherence of Serratia marcescens to aluminum.

Sixteen commercial products for use in automobile air-conditioning systems (ACS), most designated for abatement of malodors presumably of microbial origin, were examined for their potential to inhibit attachment and to detach cells of the Gram-negative bacterium Serratia marcescens on aluminum sections. Numbers of attached cells were appreciably reduced (>60%) following immersion in three alcohol-type and two acrylic-coating-type products. Several products had essentially no effect on the attached cells. Most of the products indicated for alleviation of associated microbial odors from ACS provided only short-term effects. When products were coated onto aluminum prior to exposure to the cells, water-insoluble coatings appeared to provide more consistent inhibition of primary adherence of S. marcescens. The differences in degrees of primary adherence of a selected strain of S. marcescens to variously treated aluminum provided a rapid and reproducible assessment of potential antimicrobial efficacy of ACS products.

Utility and evolution of cytochrome b in insects.

Cytochrome b (cyt-b) is widely used in molecular phylogenetic studies of vertebrate, but not invertebrate, taxa. To determine whether this situation is an historical accident or reflects the utility of cyt-b, we compared the abilities of cyt-b, COI, and one nuclear ribosomal gene region (D1 of 28S) to recover intergeneric relationships within the tiger moth tribes Ctenuchini and Euchromiini. Additionally, we compared the rate of sequence and amino acid evolution of cyt-b across insects. Cytochrome b had the same level of sequence variation and A/T bias as COI, but was less useful for recovering intergeneric relationships. The total evidence tree casts doubt on the traditional taxonomy of the group. For the class Insecta, we found that functional conservation of amino acids occurs for the same regions as those found in vertebrates with the exception of Mallophaga (lice). Lice have an accelerated rate of nonsynonymous substitutions. Accelerated rate of cyt-b nucleotide and amino acid evolution in Apidae (bees) may be correlated with increased metabolic rates associated with facultative endothermy (= heterothermy).

Volatile organic compounds associated with microbial growth in automobile air conditioning systems.

Volatile organic compounds from Penicillium viridicatum and Methylobacterium mesophilicum growing on laboratory media and on component materials of automobile air conditioners were analyzed with gas chromatography and mass spectrometry. P. viridicatum produced compounds such as 4-methyl thiazole, terpenes and alcohols, whereas M. mesophilicum produced dimethyl disulfide, dimethyl trisulfide, and chlorophenol with growth on laboratory media. In comparison with laboratory media, fewer volatiles were detected from colonized foam insulation materials. Biofilms of M. mesophilicum on aluminum evaporator components produced mainly dimethyl disulfide. These biofilms, after inoculation with P. viridicatum, produced offensive smelling alcohols and esters such as 2-methyl propanol, 3-penten-2-ol, and the ethyl ester of butanoic acid. The moisture and substrates innate to the automobile air conditioning systems provided an environment suitable for microbial biofilm development and odor production. Reduction of retained moisture in the air conditioning system coupled with use of less susceptible or antimicrobial substrates are advised for remediation of the noxious odors.

Effects of hydrogel/silver coatings on in vitro adhesion to catheters of bacteria associated with urinary tract infections.

Sections of sterile all-silicone-, hydrogel/silver-all-silicone-, and hydrogel/silver-latex-Foley urinary catheters were exposed to suspensions of bacteria and Candida albicans associated with urinary tract infections. The adhesion of these microorganisms to the catheters was determined with a radiolabel-cell procedure and scanning electron microscopy. Anomalous data with the radiolabel procedure were produced with the hydrogel/silver-latex catheters for certain species. These aberrant data were related to adhesion on the untreated cut ends of the latex catheter. Radiolabel-cell-adhesion procedures that involve sections of coated materials may need to be supplemented with additional procedures such as scanning electron microscopy for valid interpretations of the data. Adhesion to the hydrogel/silver catheters by both Gram-positive- and Gram-negative bacteria most commonly associated with nosocomial urinary tract infections, including a strain of Pseudomonas aeruginosa noted for its superior adhesion capacity, was significantly lower than the adhesion to the control all-silicone catheter.

The occurrence and persistence of mixed biofilms in automobile air conditioning systems.

Twelve automobile air conditioner systems from six manufacturers and three countries, selected mostly because of complaints of unpleasant odors in the passenger compartment, were examined for microbial growth by direct microscopy and enrichment culture. Mixed populations of fungi and bacteria (with occasional protozoa) were observed in biofilms in at least some of the components from all used units. The aluminum heat exchanger fins from ten evaporators demonstrated bacterial biofilms that yielded Methylobacterium mesophilicum. Penicillium viridicatum colonized components from four units. These bacteria and fungi were recoverable repeatedly from these units during 'dry' storage of up to 27 months. This report associates a bacterial-fungal community with disagreeable air quality in some automobiles.

Intraocular pressure control after contact transscleral diode cyclophotocoagulation in eyes with intractable glaucoma.

PURPOSE: The effect of contact transscleral diode cyclophotocoagulation (TDC) on intraocular pressure (IOP) and its safety was determined in eyes with intractable glaucoma. METHODS: The charts of 41 consecutive patients (43 eyes) who underwent the laser procedure were reviewed. After surgery, data were collected from chart entries at I hour, 1 day, 4 to 6 weeks, 4 to 6 months, and at the final visit (6-24 months). Mean differences in IOP before and after treatment were compared using the paired Student t test. Associated complications also were assessed. RESULTS: The mean +/- standard deviation follow-up period was 11.9+/-5.3 months (range, 6-24 months). One patient who died after 1 month of follow-up and another patient with neovascular glaucoma who underwent an anterior chamber washout 1 week after laser to treat an uncontrolled IOP spike were excluded from the study. Repeat treatment was done in 12 (28%) eyes. At each follow-up visit postoperatively, a significant reduction from preoperative IOP was obtained (mean reduction of 50% at the final visit). At the final visit, 64% of patients achieved an IOP of <22 mmHg and a reduction of > or =20%. An IOP spike occurred in three (7%) eyes. Long-term complications included loss of vision (> or =2 lines) in eight (22%) patients, corneal decompensation in one (2%), phthisis bulbi in one (2%), and corneal graft rejection in one (2%). CONCLUSION: Although effective IOP reduction was demonstrated in eyes with intractable glaucoma after TDC, a significant proportion (26%) of eyes had severe long-term complications.

Cataract extraction as a means of treating postfiltration hypotony maculopathy.

Hypotony maculopathy may arise after glaucoma filtering surgery. This can be treated by inducing inflammation and scarring within the filter, with the aim of increasing intraocular pressure (IOP) and promoting resolution of maculopathy. Cataract extraction can promote such inflammation. Phacoemulsification with posterior chamber intraocular lens (PC IOL) implantation was performed in two consecutive patients with postfiltration hypotony maculopathy and preexisting cataracts. After cataract extraction, improvement of IOP, visual acuity, maculopathy, and metamorphopsia occurred in both patients. Cataract extraction can be beneficial in the management of postfiltration hypotony maculopathy.

Fungal colonization of air filters and insulation in a multi-story office building: production of volatile organics.

Secondary air filters in the air-handling units on four floors of a multi-story office building with a history of fungal colonization of insulation within the air distribution system were examined for the presence of growing fungi and production of volatile organic compounds. Fungal mycelium and conidia of Cladosporium and Penicillium spp. were observed on insulation from all floors and both sides of the air filters from one floor. Lower concentrations of volatile organics were released from air filter medium colonized with fungi as compared with noncolonized filter medium. However, the volatiles from the colonized filter medium included fungal metabolites such as acetone and a carbonyl sulfide-like compound that were not released from noncolonized filter medium. The growth of fungi in air distribution systems may affect the content of volatile organics in indoor air.

Fungal colonization of air filters from hospitals.

Air filters of various types, selected on the basis of discoloration, were collected from the primary and secondary filter banks of the heating, ventilating, and air-conditioning systems in seven hospitals in the eastern United States and examined with direct microscopy for fungal colonization. Microscopic observations and culture results showed that filters from five of the hospitals were colonized with fungi including species of Acremonium, Alternaria, Aspergillus, Cladosporium, Epicoccum, Penicillium, and Rhinocladiella, and a Beauveria-like fungus. Several of these commonly airborne species, e.g., Epicoccum purpurescens (syn. E. nigrum) and Rhinocladiella sp., had not been previously reported to colonize (with conidiogenesis) air filters.

Midterm reversible failure in trabeculectomies with adjunctive mitomycin-C.

BACKGROUND AND OBJECTIVES: Trabeculectomies usually fail early (< 21 days) or late (> 6 months) when no antifibrotic agent is used. Failure is uncommon during the midterm period, between 3 weeks and 6 months. The purpose of this study is to verify the incidence of failure of trabeculectomies with mitomycin-C (MMC) during the midterm period and to evaluate the safety and efficacy of laser suture lysis (LSL) for reversing it. PATIENTS AND METHODS: The authors reviewed the records of 130 consecutive patients who underwent trabeculectomy with adjunctive MMC. RESULTS: Fourteen patients (15 eyes) had increased intraocular pressure (IOP), between 21 and 185 days (median 41 days). LSL was effective in decreasing the IOP to acceptable levels in 10 (66.6%) of the 15 eyes. No complications related to LSL were noticed. CONCLUSION: The reversibility of midterm failure seems to be a unique feature of trabeculectomies with MMC.

In vitro evaluation of the efficacy of a silver-coated catheter.

Bacteria commonly associated with nosocomial urinary tract infections were examined in vitro for their relative adherence to latex, 100% silicone-, hydrogel-coated latex-, and hydrogel/silver-coated latex urinary catheters. Degrees of adherence within 2 h were determined with cells radiolabeled with leucine. Adherence was greatest and equivalent on silicone and latex catheters. Adherence of four strains of Escherichia coli to the hydrogel/silver-coated catheter was decreased by 50% to 99% in comparison with the other catheters. Repeat testing with strains of E. coli and Pseudomonas aeruginosa with over 50 catheters demonstrated a consistency in the inhibition. The hydrophilic coating of the catheter appeared to be primary in the decreased adherence phenomenon followed by a secondary biocidal effect of the silver ion.

Corneal incision phacoemulsification and internal bleb revision.

BACKGROUND AND OBJECTIVE: Cataract extraction in filtered eyes often leads to decreased outflow and, eventually, to bleb failure. The authors describe a surgical technique that promotes preservation of the filtering bleb. PATIENTS AND METHODS: The authors retrospectively reviewed 19 eyes of 19 consecutive patients who underwent corneal incision phacoemulsification and simultaneous internal revision of the previous filtering bleb. RESULTS: The mean follow-up time was 13.6 +/- 7.6 months. Visual acuity improved in all patients (89.4 percent achieved 20/40 or better). No significant difference was noted between preoperative and postoperative intraocular pressures and astigmatism. The bleb was preserved in 89.4 percent of the eyes at the time of the last follow-up. CONCLUSIONS: This surgical technique proved to be safe and yielded good results.

Fungal colonization of fiberglass insulation in the air distribution system of a multi-story office building: VOC production and possible relationship to a sick building syndrome.

Complaints characteristic of those for sick building syndrome prompted mycological investigations of a modern multi-story office building on the Gulf coast in the Southeastern United States (Houston-Galveston area). The air handling units and fiberglass duct liner of the heating, ventilating and air conditioning system of the building, without a history of catastrophic or chronic water damage, demonstrated extensive colonization with Penicillium spp and Cladosporium herbarum. Although dense fungal growth was observed on surfaces within the heating-cooling system, most air samples yielded fewer than 200 CFU m-3. Several volatile compounds found in the building air were released also from colonized fiberglass. Removal of colonized insulation from the floor receiving the majority of complaints of mouldy air and continuous operation of the units supplying this floor resulted in a reduction in the number of complaints.

Dynamic interactions between nerve and muscle in Caenorhabditis elegans.

Synaptogenesis among developing motoneurons and muscles was examined in the nematode Caenorhabditis elegans. In this animal embryonic precursor cells give rise to regionally localized, contiguous clones of muscle cells that form two dorsal and two ventral sets that run longitudinally along the body wall. Ablation of selected embryonic muscle precursors resulted in gaps in the posterior dorsal muscle quadrants. We compared the morphological development of GABAergic locomotory neurons in the presence and absence of their target muscle cells. The results led to four main conclusions: (1) target muscle cells are not required for the morphological differentiation of the motoneurons; (2) target muscle cells appear to be required for the formation of presynaptic varicosities by the motoneurons; (3) embryonic muscle cells serve as a guide for migrating postembryonic muscle cells and in the absence of these guides the postembryonic muscles often assume ectopic locations; and (4) in the presence of ectopic muscle cells, the GABAergic locomotory neurons sprouted and formed branches that contributed to ectopic neuromuscular junctions.

Resistance of adhered bacteria to rigid gas permeable contact lens solutions.

We examined eight conditioning or disinfecting solutions recommended for use with rigid gas permeable (RGP) or hard contact lenses for their efficacy against planktonic and attached cells of bacteria and Candida albicans. Most solutions, particularly those containing phenylmercuric nitrate and polyaminopropyl biguanide, gave marked inhibition (99.99% reduction within 4 hours) of planktonic cells of bacteria. Planktonic cells of Serratia marcescens and C. albicans survived in certain solutions containing chlorhexidine and benzalkonium chloride. In contrast, cells of all test microorganisms adhered to wells of polyethylene contact lens cases showed various degrees of survival after 4, 6, and 12 hours of exposure to most contact lens solutions. Drying of the lens case with adhered cells for 10 hours prior to addition of the lens solution usually reduced the incidence of recovery. Studies demonstrated that biofilms developed in cases with solutions of low and high efficacy. The enhanced resistance of adhered cells requires the periodic disinfection or replacement of lens cases used with RGP lenses.