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Resistance of cotton rats, Sigmodon hispidus, to primary infection by Nippostrongylus brasiliensis.

The resistance of cotton rats, Sigmodon hispidus to Nippostrongylus brasiliensis infection was examined and compared the response to that of the susceptible Indian soft-furred rat, Millardia meltada. After a primary infection with infective third-stage N. brasiliensis larvae (L3), the number of eggs in feces and adult worm recovery rates from the small intestine of cotton rats were significantly lower than in the controls. To determine whether cotton rat resistance was observed during the migratory phase or the intestinal phase, cotton rats and control animals were challenged subcutaneously with L3 or intraduodenally with adult worms, and larval recovery from lungs and adult worm burden were evaluated. The recovery rate of larvae from the lungs of cotton rats was about five-fold lower than from controls. Adult worm recovery from the small intestine of cotton rats was also lower than that from the controls, but the difference (two-fold lower) was smaller than that observed for lung recovery. Carbon treatment at a dose of 250-500 mg/kg effectively increased larval worm recovery from the lungs of cotton rats. However, this treatment had no effect on worm recovery from the intestine after intraduodenal implantation of adult N. brasiliensis. These results suggest that macrophage function have important role in the expression of strong resistance during the migratory phase of N. brasiliensis infection in cotton rats.

Animals↗

Use of the cotton swab method in diagnosing Tinea capitis.

OBJECTIVE: To evaluate the accuracy of the cotton swab technique for identifying fungal infections of the scalp. The purpose of the study was: 1) to compare the cotton swab technique with the toothbrush method, a popular and reliable means for obtaining specimens; and 2) to ascertain if transport of a specimen, entailing variable transport duration and conditions, impairs the sensitivity and specificity of the technique. MATERIALS AND METHODS: Part 1 consisted of a prospective, investigator-blinded comparison analysis. Fifty children with scalp findings suspicious for tinea capitis were cultured using both techniques: the toothbrush and cotton swab. Ninety-six culture results were obtained for analysis. The second part of the study consisted of a prospective comparison analysis of cotton swab culture results obtained from samples plated immediately after collection in the physician's office as compared with samples transported to outside laboratories for processing. Thirty-one children with presumed tinea capitis were cultured twice with the cotton swab technique; one sample was immediately plated onto fungal medium and the other sent to an outside lab, the selection of which was dictated by the patient's insurance plan. A total of 62 samples were obtained; 58 sample results were used for analysis. RESULTS: In part 1 of the study, 60% of the 48 children analyzed had positive fungal cultures. Eighty percent of these were Trichophyton species. There was 100% agreement in the results obtained; all patients with positive results using the toothbrush method were also positive when the cotton swab method was used. Similarly, there was complete concordance in laboratory results from the second part of the study. Fifty percent of the 28 children analyzed had positive cultures; 86% grew Trichophyton species. All patients who had positive cultures from those samples plated in-office also had positive results from the outside laboratory samples. CONCLUSIONS: The cotton swab technique is an easy, atraumatic, inexpensive, and reliable means to evaluate patients with suspected tinea capitis. The method remains sensitive and specific even when transport of these specimens is required and processing is thus delayed. This painless technique requires little technical expertise and can be rapidly performed with a standard cotton tip applicator. It should prove an invaluable aid to practitioners in evaluating patients with possible fungal infections of the scalp.

Adolescent↗

Dynamics and seasonal abundance of stink bugs (Heteroptera: Pentatomidae) in a cotton-soybean ecosystem.

Two soybean varieties (early-maturing group V and late-maturing group VII) and two cotton varieties (conventional and transgenic (Bt) were grown in adjacent replicated large field plots (approximately 0.1 ha each) at two locations for 3 yr. The dynamics and relative abundance of phytophagous stink bugs within these two crops were observed. The most abundant pentatomid species in both crops for all 3 yr were Nezara viridula (L.), Acrosternum hilare (Say), and Euschistus servus (Say). Several other species also were commonly collected. This is the first record of Mormidea lugens (F.) on soybean and E. quadrator Rolston, E. obscurus (Palisot), Holcostethus limbolarius (Stål), and Oebalus pugnax (F.) on cotton. Stink bugs began arriving in soybean when plant growth stages ranged from pod formation to full seed development. Peak numbers of these insects were found in soybean from the time of full-size seeds in the pods until early maturity. The bugs were first attracted to the earlier maturing cultivar (group V), where they remained until plants began to mature (R7). The pentatomids then moved to the later-maturing cultivar (group VII) as it reached full pod to full seed. Stink bugs began arriving in cotton from the time of the earliest flowers until after the first bolls formed. Peak numbers in cotton occurred during the time when all stages of developing bolls were present. Stink bug numbers were much greater in soybean than in cotton over all three seasons. This preference for soybean over cotton indicates the potential use of soybean as a trap crop for attracting stink bugs away from cotton. Additionally, the coordinated use of early- and late-maturing soybean cultivars as a trap crop could minimize the area requiring insecticides, as well as the number of insecticide applications to cotton.

Animals↗

Resistance of aphis gossypii (Homoptera: Aphididae) to fenvalerate and imidacloprid and activities of detoxification enzymes on cotton and cucumber.

Resistance of two strains of cotton aphid, Aphis gossypii Glover, to fenvalerate and imidacloprid were determined on cotton (Gossypium hirsutum L.) and cucumber (Cucumis sativa L.) after resistance selection of one strain to fenvalerate for 16 consecutive generations, and of a second strain to imidacloprid for 12 consecutive generations on cotton in greenhouses. Dose-response and activities of detoxication enzymes of the fenvalerate-resistant strain (R-fenvalerate), the imidacloprid-resistant strain (R-imidacloprid), and a susceptible strain (S) were determined. After 16 consecutive generations of selection, resistance of A. gossypii to fenvalerate increased >29,000-fold and to imidacloprid 8.1-fold. On cucumber. resistance of the R-fenvalerate strain to fenvalerate increased 700-fold and to imidacloprid 3.6-fold. However, the most significant finding in this study was that the R-imidacloprid strain exhibited cross-resistance to fenvalerate, with a resistance ratio of 108.9-fold on cotton and 3:3.5-fold on cucumber, whereas the R-fenvalerate strain did not show significant cross-resistance to imidacloprid on either plant species. Both resistant strains of A. gossypii were more resistant to fenvalerate on cotton than on cucumber, whereas their susceptibility to imidacloprid on otton and cucumber were not significantly different. The response of the S strain to fenvalerate and imidacloprid were similar on cotton and Cucumber. Activities of acetylcholinesterase (AChE) and alpha-naphthylacetate (alpha-NA) esterases of A. gossypii were significantly different among the three strains, with the R-fenvalerate strains having the highest, followed by the R-imidacloprid strain, and the S strain the lowest. The activities of the AChE and alpha-NA esterases for all three strains were also significantly higher on cotton than on cucumber. The resistance mechanism and resistance management strategies for the R-fenvalerate and R-imidacloprid strains of A. gossypii to fenvalerate and imidacloprid on cotton and cucumber are discussed.

Acetylcholinesterase↗

Effects of kaolin-based particle film application on boll weevil (Coleoptera: Curculionidae) injury to cotton.

This study examined a non-insecticidal tactic for suppressing boll weevil, Anthonomus grandis grandis Boheman, damage to cotton, Gossypium hirsutum L. In cage assays, kaolin, a reflective white mineral, applied to excised cotton squares or to the cotton foliage, initially resulted in lower levels of boll weevil injury to squares than nontreated squares. Boll weevil oviposition and feeding on kaolin-treated squares and squares on kaolin-treated cotton plants increased when nontreated squares and cotton plants were in short supply. A laboratory assay and field trials suggested that boll weevils distinguished between cotton plots based on color differences caused by kaolin and this appeared to influence levels of damage to squares. Random sampling in small plots indicated that oviposition damage to squares in plots treated with kaolin was reduced (P < 0.05) compared with nontreated controls, except when rain washed the kaolin off the foliage. Lint yield differences were not detected between the small plots, but the kaolin-treated small plots yielded as much as 2.36 times more cotton lint than a large but unreplicated adjacent nontreated control plot, and up to 1.39 times more than another large but unreplicated adjacent plot sprayed twice with preemptive applications of azinphosmethyl when cotton squares were first developing (pinhead stage). Potentially important avenues for future research on boll weevil injury suppression using kaolin are discussed.

Animals↗

Potential of yellow sticky traps for lady beetle survey in cotton.

A 2-yr study was conducted to investigate the potential of using yellow sticky traps to survey lady beetles in cotton and to quantify seasonal activity patterns. The performance of sticky traps was compared with that of a 2-cycle vacuum sampler. The most common lady beetle species captured by sticky traps and vacuum sampler in cotton were Hippodamia convergens Guerin-Meneville and Scymnus loewii Mulsant. Sticky traps captured significantly more of both species of lady beetles, had greater capture efficiency, and more effectively detected lady beetles compared with the vacuum sampler. These data indicate that the sticky trap can be a valuable tool in monitoring lady beetle populations in cotton. In the second part of this study, a year-round survey of lady beetle populations in the periphery of a cotton farm using sticky traps showed that lady beetles remained active throughout the year in the Texas Rolling Plains, but the activity was influenced by winter severity. Over a 2-yr period, H. convergens, S. loewii, Coccinella septempunctata (L.), and Olla v-nigrum (Mulsant) comprised 89.6, 8.2, 1.9, and 0.3% of the specimens, respectively. Sticky trap captures were affected by year, trap height, and cropping season. Traps placed at 0.75 m above ground captured significantly more (80%) lady beetles than traps placed at 1.50 m (20%) above ground; traps at 0.75 m above ground also detected the rarer species while the traps at 1.50 m above ground detected only the abundant species. Trap captures were higher during the noncotton season (November to April) compared with the cotton season (May to October). A significant positive correlation between cotton aphid abundance during the growing season and H. convergens abundance during the following noncotton season was also detected, indicating a significant movement of H. convergens from cotton to the periphery of the farm to seek refuge after cotton termination.

Animals↗

Bollgard cotton and resistance of tobacco budworm (Lepidoptera: Noctuidae) to conventional insecticides in southern Tamaulipas, Mexico.

Insecticide susceptibility in tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), was determined for 8 yr (1991-2001) with larvae sampled from cotton in southern Tamaulipas, Mexico. Before 1996, when Bollgard cotton expressing the Cry1A(c) delta-endotoxin was introduced into the region, two important patterns were documented. The first was economically significant increases in resistance to certain insecticide groups. The second was occurrence of virtually complete control failures in the field during 1994 and 1995. The largest resistance changes were recorded for the type II pyrethroids cypermethrin and deltamethrin. These products are the most widely used products in the region. Resistance ratios for these products increased up to > 100-fold from 1991 to 1995. After 1996, the resistance levels declined. These findings did not occur with other products of scant use (e.g., permethrin, profenofos, and endosulfan) or low tobacco budworm efficacy coupled to a high use pattern (e.g., methyl parathion). This clear trend toward reversal of resistance to type II pyrethroids can be understood, in part, with respect to two factors: 1) the high adoption rate of transgenic cotton in the region, from 31.2% in the beginning (1996) to approximately 90% in 1998; this has considerably curbed the use of synthetic insecticides, with the attending loss of selection pressure on this pest; and 2) the potential immigration to the region of susceptible tobacco budworms from cultivated and wild suitable hosts as well as from transgenic cotton might have influenced the pest population as a whole. The influence of transgenic cotton on southern Tamaulipas can be more clearly seen by the drastic reduction of insecticide use to control this important pest. Now tobacco budworms in this region are susceptible to type II pyrethroids. Two effective and fundamentally different pest management tools are now available to cotton growers in southern Tamaulipas: transgenic cotton, coupled with careful use of pyrethroids, offers the possibility of sustainable and profitable cotton production.

Animals↗

Microbial contamination of water-soaked cotton gauze and its cause.

Seven in-use cotton gauze samples and three cotton balls soaked in sterile distilled water in canisters were investigated 7 days after they were prepared in hospital. All samples were contaminated with bacteria including 10(6) to 10(7) colony forming units/ml of Pseudomonas aeruginosa. In vitro viability tests using cotton gauze and cotton balls soaked in sterile distilled water revealed rapid proliferation of P. aeruginosa, Serratia marcescens and Candida albicans. Since the cotton gauze and the cotton balls were soaked in water containing nutrients, such as protein and glucose, these materials may be readily contaminated with bacteria including P. aeruginosa. Thus, when using cotton gauze and cotton balls containing water, microbial contamination should be expected.

Candida albicans↗

The pattern of lung function abnormalities in cotton textile workers.

Reversible airway obstruction has been shown to be a characteristic finding of early byssinosis. In the chronic phase of this disease, the patterns of respiratory abnormalities have not been well defined. We examined the lung function of a cohort of 383 older (45 yr of age or more), active and retired, cotton textile workers seen both in 1973 and in 1979 in Columbia, South Carolina. A group of control subjects consisted of 277 white community residents of comparable age from Lebanon, Connecticut. Using data at follow-up, 25% of the male and 14% of the female cotton textile workers had moderate to severe obstructive airway abnormalities, as opposed to 13 and 5% for male and female control subjects (p less than 0.01). There were fewer persons with restrictive than with obstructive lung patterns among cotton textile workers and control subjects, but again, abnormalities were more prevalent among cotton textile workers. Overall, 50% of male cotton textile workers and 37% of female cotton textile workers had some abnormality of lung function, as opposed to 29% of male and 20% of female control subjects (p less than 0.001). More abnormalities were present in cotton textile workers than in control subjects when only lifetime nonsmokers were examined. We conclude that there is an increased prevalence of both obstructive and restrictive lung function abnormalities among cotton textile workers when compared with control subjects, with the most common pattern being obstructive.

Age Factors↗

Early region 3-replacement adenovirus recombinants are less pathogenic in cotton rats and mice than early region 3-deleted viruses.

BACKGROUND: Adenovirus type-5 (Ad5) recombinant viruses with replacement of the 1.9 kb XbaI fragment in the early region 3 (E3) by foreign genes have been constructed with the ultimate goal of inducing immune responses to the product of the inserted gene against a variety of virus infections. The pathogenicity of these recombinants, however, has not been studied. EXPERIMENTAL DESIGN: Histopathologic changes induced in cotton rat and mouse lung by E3-replacement-Ad5 recombinant or wild-type Ad (Wt-Ad) or E3-deleted mutant (Ad5-delta E3) viruses were compared. Expression of viral mRNA and replication of these viruses in cotton rat and mouse lungs, as well as in human tissue culture cells, were assayed. Expression of class I major histocompatibility complex antigens and the E3-14.7 kilodalton protein in virus-infected cells were also analyzed. RESULTS: An Ad5 recombinant, Ad-human cytomegalovirus glycoprotein B (Ad-HCMV.gB), in which the E3 region is replaced by the full-length gB gene of HCMV and with a genome size exceeding that of Wt-Ad, induced mild histopathologic responses in cotton rat and mouse lungs, comparable with those of Wt-Ad, but less severe than those of Ad5-delta E3. Analysis indicated that neither class I major histocompatibility complex expression on the cell surface nor differential expression of the protective E3-14.7 kilodalton protein underlies the pathologic differences observed in cells infected with Ad5-delta E3 or the Ad-HCMV.gB recombinant. In the mouse lung, another Ad-E3 replacement recombinant, Ad-herpes simplex glycoprotein B (HSV.gB), containing the complete HSV.gB gene and with a genome size larger than that of Wt-Ad, also induced a very mild inflammatory response. However, two recombinants with truncated forms of the HCMV.gB (Ad-HCMV.gB.155) or HSV.gB genes (Ad-HSV.gB.147) produced more severe histopathologic changes than the Wt-Ad or the recombinants with the full complement of HCMV.gB or HSV.gB genes. Ad5 and some of the recombinants replicated in mouse and cotton rat lung, and the extent of replication was inversely proportional to genome size, both in the lung and in human tissue culture cells. Infectious virus titers were, however, higher in cotton rat than in mouse lung. In situ hybridization analysis of cotton rat and mouse lung infected with Wt-Ad, Ad5-delta E3, or Ad-HCMV.gB virus revealed expression of Ad early/late mRNA predominantly in bronchial epithelial cells. CONCLUSIONS: These data not only confirm that E3-deleted viruses induce more severe pathologic changes in cotton rat lungs than Wt-Ad viruses (Ginsberg et al., Proc Natl Acad Sci USA 1989;86:3823-7) but led to the observation that some E3 replacement recombinants also lacking the expression of the 19 and 14.7 kilodalton proteins are significantly less pathogenic in cotton rats and mice than an E3-deleted virus. Pathogenicity and replication of the recombinant viruses inversely correlate with the genomic size.

Adenoviridae↗

Genome-wide identification and analysis of paclobutrazol-resistance gene family in cotton and the positive role of GhPRE3 in salt stress and drought stress resistance.

Compared with other transcription factors, much less studies have been performed on paclobutrazol-resistance (PRE), a subgroup of the extensive bHLH transcription factor gene family, and the research in cotton was also limited. By utilizing the PRE genes and their conserved domains identified in Arabidopsis, a total of 23, 22, 11, and 12 PRE genes were identified from two major cultivated cotton species and their two ancestors, respectively. The cotton PRE gene family was categorized into three subgroups based on evolutionary tree analysis. Motif and intron analyses indicated that the PRE gene has remained highly conserved throughout evolution. Collinearity analysis indicated that gene duplication, particularly through fragment replication, has significantly contributed to the expansion of the cotton PRE family. An exploration of the conserved elements within the PRE gene family uncovered numerous elements associated with plant stress resistance. Additionally, cotton transcriptome and qRT-PCR analysis showed that PRE genes were associated with a variety of abiotic stresses, including salt, drought, and cold treatments. Subcellular localization experiments indicated that the GhPRE3 gene is associated with membrane proteins. Finally, we selected the GhPRE3 gene for a VIGS experiment, which revealed that under salt stress and drought stress conditions, the wilting of leaves in the GhPRE3-silenced plants was significantly more severe than that observed in the control group, with T-AOC levels notably lower and MDA levels significantly higher. Overexpression of GhPRE3 enhanced seed germination and root development in transgenic Arabidopsis thaliana under salt stress and drought stresses. This suggests that GhPRE3 plays a positive regulatory role in cotton tolerance to salt and drought stressed, providing a reference for molecular genetic breeding of cotton with salt and drought tolerance.

Gossypium↗

Saliva collection using cotton buds with wooden sticks: a note of caution.

The aims of the present study were to investigate whether the cotton-tipped applicators (cotton buds) used to collect saliva in infants can be stored un-centrifuged prior to cortisol analysis, and to test whether there is any difference in results between wooden and plastic-shafted sticks. Saliva was collected from 10 healthy adults using 6 cotton buds, i.e. 3 with wooden sticks and 3 with plastic sticks. The samples were then centrifuged at three different time-points: immediately after collection, after 24 h and after 48 h. Using cotton buds with wooden sticks, median salivary cortisol was significantly lower after 24 h (40 %) (p<0.001) and after 48 h (49 %) (p<0.001) of storage than it was of the samples centrifuged immediately. There was no significant difference between the samples centrifuged immediately and those centrifuged after 24 h and 48 h when saliva was collected using the cotton buds with plastic sticks. It is concluded that cotton buds with wooden sticks should not be used in studies of salivary cortisol unless it is possible to centrifuge the saliva immediately. Moreover, it is inadvisable to alternate between cotton buds with wooden and plastic sticks in the same study when collecting saliva for analysis of cortisol.

Adult↗

Isolation and analyses of genes preferentially expressed during early cotton fiber development by subtractive PCR and cDNA array.

Cotton fibers are differentiated epidermal cells originating from the outer integuments of the ovule. To identify genes involved in cotton fiber elongation, we performed subtractive PCR using cDNA prepared from 10 days post anthesis (d.p.a.) wild-type cotton fiber as tester and cDNA from a fuzzless-lintless (fl) mutant as driver. We recovered 280 independent cDNA fragments including most of the previously published cotton fiber-related genes. cDNA macroarrays showed that 172 genes were significantly up-regulated in elongating cotton fibers as confirmed by in situ hybridization in representative cases. Twenty-nine cDNAs, including a putative vacuolar (H+)-ATPase catalytic subunit, a kinesin-like calmodulin binding protein, several arabinogalactan proteins and key enzymes involved in long chain fatty acid biosynthesis, accumulated to greater than 50-fold in 10 d.p.a. fiber cells when compared to that in 0 d.p.a. ovules. Various upstream pathways, such as auxin signal transduction, the MAPK pathway and profilin- and expansin-induced cell wall loosening, were also activated during the fast fiber elongation period. This report constitutes the first systematic analysis of genes involved in cotton fiber development. Our results suggest that a concerted mechanism involving multiple cellular pathways is responsible for cotton fiber elongation.

Cell Division↗

Is chronic airway obstruction from cotton dust exposure reversible?

BACKGROUND: Exposure to cotton dust is known to cause chronic airway obstruction, but there is little information on whether the obstructive impairment is reversible after the exposure stops. METHODS: Longitudinal changes in lung function were evaluated among 429 cotton textile workers and 449 silk workers in Shanghai, China, beginning in 1981. Both active and retired workers were tested every 4 to 6 years for 15 years. RESULTS: Overall, cotton workers had greater annual declines in forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC). Compared with active workers, retired cotton workers had lower annual loss of FEV1, although the retired workers had a greater loss during their active employment than the currently active workers. No such trends were detected in silk workers. Annual declines in FEV1 in retired cotton workers were smaller with increasing time since retirement. Multivariate analysis showed that retirement was a substantial contributing factor for improved FEV1 and FVC in the cotton workers, especially among those who did not smoke. Correspondingly, remission of airflow obstruction, defined as a ratio of FEV1 and FVC of less than 70%, was more common in retirees than in the active workers, and more common in nonsmokers than in smokers. CONCLUSION: Chronic airway obstruction related to long-term exposure to cotton dust may be partially reversible after the exposure ceases, although lung function does not return to the level found in unexposed workers.

Adult↗

Molecular characterization of the cotton GhTUB1 gene that is preferentially expressed in fiber.

Each fiber of cotton (Gossypium hirsutum) is a single epidermal cell that rapidly elongates to 2.5 to 3.0 cm from the ovule surface within about 16 d after anthesis. A large number of genes are required for fiber differentiation and development, but so far, little is known about how these genes control and regulate the process of fiber development. To investigate gene expression patterns in fiber, a cDNA, GhTUB1, encoding beta-tubulin was isolated from a cotton fiber cDNA library. The analyses of RNA northern-blot hybridization and reverse transcriptase-polymerase chain reaction demonstrated that GhTUB1 transcripts preferentially accumulated at high levels in fiber, at low levels in ovules at the early stage of cotton boll development, and at very low levels in other tissues of cotton. The corresponding GhTUB1 gene including the promoter region was isolated by screening a cotton genomic DNA library. To demonstrate the specificity of the GhTUB1 promoter, the 5'-flanking region including the promoter and 5'-untranslated region was fused with the beta-glucuronidase reporter gene. The expression of the reporter chimera was examined in a large number of transgenic cotton plants. Histochemical assays demonstrated that GhTUB1::beta-glucuronidase fusion genes were expressed preferentially at high levels in fiber and primary root tip of 1- to 3-d-old seedlings and at low levels in other tissues such as ovule, pollen, seedling cotyledon, and root basal portion. The results suggested that the GhTUB1 gene may play a distinct and required role in fiber development. In addition, the GhTUB1 promoter may have great potential for cotton improvement by genetic engineering.

Arabidopsis Proteins↗

[Existant quality problems and suggestions for quality control of medical absorbent cotton].

In the process of acid hydrolysis of medical absorbent cotton, we have discovered that some of the domestic manufactured medical absorbent cotton is mixed with wasted non-cotton chemical fiber. If the cotton is used in medical treatments, the chemical fiber will cause irritation, allergy and inflammation, so it's very harmful. But the non-cotton fiber content is not stipulated in the standard of YY0330-2002, and no testing method for it is available. In this paper we discuss the existent quality problems, the control and the test method for non-cotton chemical fiber in medical absorbent cotton.

Bandages↗

Cotton-wool spots in acquired immunodeficiency syndrome compared with diabetes mellitus, systemic hypertension, and central retinal vein occlusion.

The cotton-wool spot is a common fundus finding in patients with many ocular and systemic diseases. We investigated the characteristics of cotton-wool spots in patients with four major diseases, ie, acquired immunodeficiency syndrome, diabetes mellitus, systemic hypertension, and central retinal vein occlusion, to see if any differences were detected in their number, size, or location. A composite of all the cotton-wool spots for each of these four categories was obtained by computed reconstruction to analyze variations in their distribution and size. The cotton-wool spots had a predilection for the temporal quadrants in the four categories and were smaller in patients with acquired immunodeficiency syndrome than the other groups. Patients with ischemic central retinal vein occlusion had more cotton-wool spots than the other groups. No other definite differences were detected. Cotton-wool spots than the other groups. No other definite differences were detected. Cotton-wool spots seem to be a common pathway following various insults to the retina, most probably of a vaso-occlusive origin.

Acquired Immunodeficiency Syndrome↗

Cotton dust and endotoxin exposure and long-term decline in lung function: results of a longitudinal study.

BACKGROUND: To evaluate the relationship between long-term exposure to cotton dust and Gram-negative bacterial endotoxin on lung function, we conducted an 11-year follow-up study of cotton textile workers in Shanghai, China. METHODS: Workers at a nearby silk-thread manufacturing mill were used as a referent population. Ninety percent of the original cohort of 445 cotton and 467 silk textile workers--both active and retired--were identified for testing in the 11th year. Questionnaires and spirometric testing were performed, as well as cotton dust and endotoxin sampling at three points over the 11-year follow-up period: at baseline, at Year 5, and at Year 11. After excluding deaths and subjects on sick-leave, 84% of the original cohort had complete health and environmental data. RESULTS: The data were reanalyzed using generalized estimating equations feedback model which allow for subject transfer over time between work areas, various exposure levels to dust and endotoxin, and FEV1. Cotton workers had a larger loss of FEV1 during the first 5 years of study (-40 mls/yr) as compared with the second 6 years of follow-up (-18 mls/yr). During the same periods, the average decline among silk workers was slightly higher in the first period, but was more consistent (-30 mls/yr vs. -27 mls/yr), and these differences could not be explained by worker selection or dropout. When cumulative exposure to dust and endotoxin were estimated and used in a multivariate model (GEE) for FEV1 loss, cumulative dust, but not endotoxin, was associated with 11-year loss in FEV1 after adjustments for confounders. There was evidence of feedback between dust-exposure levels and FEV1, indicating the existence of a healthy-worker survivor effect. After accounting for a healthy-worker survivor effect, we found a significant relationship between dust exposure and FEV1 decline. CONCLUSIONS: Our results suggest that cotton dust is more strongly associated with chronic airflow limitation than associated endotoxins. Further work is needed to clarify potential reversibility after cessation of exposure, and the relative contributions of dust, endotoxin, and tobacco to chronic respiratory impairment in cotton and other vegetable-exposed workers.

Case-Control Studies↗