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EST derived PCR-based markers for functional gene homologues in cotton.

We investigated the utility of the Gossypium arboreum EST sequences in the GenBank database for developing PCR-based markers targeting known-function genes in cultivated tetraploid cottons, G. hirsutum and G. barbadense. Four hundred sixty-five randomly selected ESTs from this library were subjected to BLASTn search against all GenBank databases, of which putative function was assigned to 93 ESTs based on high nucleotide homology to previously studied genes. PCR primers were synthesized for 89 of the known-function ESTs. A total of 57 primer pairs amplified G. arboreum genomic DNA, but only 39 amplified in G. hirsutum and G. barbadense, suggesting that sequence divergence may be a factor causing non-amplification for some sites. DNA sequence analysis showed that most primer pairs were targeting the expected homologous loci. While the amplified products that were of larger size than the corresponding EST sequences contain introns, the primer pairs with a smaller amplicon than predicted from the flanking EST sequences did not amplify the expected orthologous gene sequences. Among the 39 primer pairs that amplified tetraploid cotton DNA, 3 detected amplicon size polymorphisms and 10 detected polymorphisms after digestion with one of six restriction enzymes. Ten of the polymorphic loci were subsequently mapped to an anchor RFLP map. Digestion of PCR-amplified sequences offers one means by which cotton genes can be mapped to their chromosomal locations more quickly and economically than by RFLP analysis.

Base Sequence↗

Human respiratory syncytial virus affects nonadrenergic noncholinergic inhibition in cotton rat airways.

A dysfunction of the nonadrenergic noncholinergic inhibitory (NANCi) system has been invoked as a possible mechanism underlying or contributing to altered airway function. In the present study we assessed whether human respiratory syncytial virus (HRSV) infection affects the airways' neurally mediated contractile and relaxant (NANCi) responses in vitro. NANCi responses were studied on tracheal smooth muscle (TSM) segments obtained from young adult cotton rats, a well-established model for HRSV infection. To assess NANCi responses, TSM segments were removed and placed in tissue baths containing modified Krebs-Henseleit, atropine (1 x 10(-6) M) and propranolol (5 x 10(-6) M). After contraction with neurokinin A (1 x 10(-5) M), electrical field stimulation (EFS) was applied at stimulation frequencies ranging from 5 to 30 Hz. The NANCi responses were measured and expressed as the mean (+/- SE) percent relaxation. To evaluate neurally mediated contractile responses, full frequency response curves (0.5-30 Hz) to EFS were also performed. We found significantly decreased NANCi responses in TSM segments obtained from infected cotton rats (n = 12) compared with control animals (n = 9) (P < 0.002). Furthermore, the contractile responses to EFS were increased in infected animals compared with the control group (P = 0.0001). These findings demonstrate that HRSV infection leads to an enhanced contractile response to EFS and a significant decrease in NANCi response in cotton rat airways in vitro. This disruption of the neural control of airways may lead to the development of altered airway function.

Animals↗

ECL-cell derived gastric cancer in male cotton rats dosed with the H2-blocker loxtidine.

Spontaneously hypergastrinemic cotton rats (Sigmodon hispidus) develop tumors that have the phenotype of an adenocarcinoma but most likely originate from the enterochromaffin-like (ECL) cells. Among inbred animals approximately 50% of the females, but <1% of males develop spontaneous gastric carcinomas. Gastrin is the principle carcinogen in this model, as >4 months of hypergastrinemia results in carcinoma, but a gastrin receptor antagonist prevents carcinomas. Carcinomas can also be induced by partial corpectomy. In the present study, the insurmountable H2-receptor antagonist loxtidine (200 mg/kg/day) was given to male cotton rats for 6 months. The loxtidine-dosed animals developed hypergastrinemia, whereas control animals remained normogastrinemic. At termination, 4 of 5 cotton rats had cancer located to the oxyntic mucosa, whereas 1 animal had dysplasia. The gastric mucosa of all of the control animals was normal. In the dysplastic mucosa of loxtidine-dosed animals there was a marked increase in chromogranin A-positive cells, where numerous groups of cells also stained positive with the Sevier-Munger technique. In areas of high proliferation and cancer there were also histidine decarboxylase, chromogranin A, and Sevier-Munger-positive cells, altogether indicating an ECL cell origin of the tumors. This represents an interesting animal model where ECL cell-derived gastric cancer can be induced by pharmacological acid inhibition in 6 months.

Animals↗

Comparison of aqueous grain dusts, cotton dusts, and mold extracts by crossed immunoelectrophoretic techniques.

To evaluate the possibility that an immune response is involved in the pathogenesis of grain dust or cotton dust induced respiratory disease, 1 grain dust extract (A) was compared with 4 similar grain dust extracts, a cotton dust extract, and a mixture of fungal preparations, using crossed immunoelectrophoretic techniques and rabbit anti-A sera. All extracts demonstrated a significant number of shared antigenic determinants. These data suggest that grain and cotton dust may induce disease via a common pathogenic mechanism and putative agent(s).

Allergens↗

Cotton bract tannin: a novel human T-lymphocyte mitogen and a possible causative agent of byssinosis.

Cotton bract tannin, a major organic component of cotton dust, was tested for mitogenic activity upon human T lymphocytes. Tannin caused polyclonal activation of human T lymphocytes in vitro. The pattern of T-cell response to tannin was similar to the pattern seen in lymphocytes stimulated with the well-known plant lectin T-cell mitogens, PHA and ConA. The response to tannin was shown to be dependent upon tannin dose and presence of monocytes. The maximum response occurred after 3-4 days in culture with the magnitude comparable to the one achieved by ConA. Lipopolysaccharide from Enterobacter agglomerans, a major contaminant of cotton dust, was shown not to be a mediator of tannin mitogenicity in vitro. A role for tannin as a polyclonal cell activator and, therefore, a possible etiologic agent of byssinosis is suggested by these observations.

Antigen-Presenting Cells↗

Polyester but not cotton or wool textiles inhibit hair growth.

The effect of different types of textile fabrics on hair growth was investigated in 40 mongrel dogs divided into 5 groups. An area of 10 x 20 cm on the dog's back was shaved; half of this area was covered by a textile patch of 100% polyester material in the 1st group, 100% cotton in the 2nd group, 100% wool in the 3rd group and a 50%/50% polyester/cotton blend in the 4th group. The remaining half of the shaved area in the 4 groups as well as the whole area in the 5th group (control) were left uncovered. The textile patch was worn for 2 months. The polyester-covered hair grew at a significantly lower rate and density than in the uncovered area of the same animal and the controls (p < 0.01). The hair color was similar to that of the surrounding uncovered hair. This is in contrast to cotton- and wool-covered skin area which showed nonsignificant differences in hair density, growth rate and color (p > 0.05) against the uncovered area and controls. In the polyester-covered skin, a thinning of the epidermis of the skin was noted microscopically with fragmentation and vacuolation of the hair follicle pulp. The study has shown that the polyester material generated electrostatic potentials, which may have inhibited hair growth, whereas cotton and woolen textiles did not. Friction between the polyester textile and the skin generates electrostatic charges which are suggested to create an 'electrostatic field' that seems to be responsible for the inhibited hair growth.

Animals↗

Cotton dust and across-shift change in FEV1 as predictors of annual change in FEV1.

In this report of a 5-yr longitudinal study of workers employed at six cotton textile mills, exposure and across-shift FEV1 change were evaluated as possible predictors of the annual change in FEV1 for yarn manufacturing workers. A total of 611 workers had three repeatable spirometric tests, over at least 3 yr, and at least one (average of three) across-shift test, while always working the same shift. The "same shift" criterion controlled for the effect of diurnal variation. Average exposure was determined from measures of lint-free elutriated cotton dust in combination with job histories. This study found a significant association between the acute and chronic effects of cotton dust exposure. Both exposure and across-shift change proved to be significant predictors of annual change, and excess annual declines in FEV1 were predicted even for exposures of 200 micrograms/m3 and across-shift drops in FEV1 of 200 ml. These results suggest that, to prevent dust-related chronic decline in lung function, current smokers should be excluded from yarn manufacturing work and exposures should be reduced below 200 micrograms/m3, to approximately 100 micrograms/m3.

Acute Disease↗

Correlation of cytotoxic activity in lungs to recovery of normal and gamma-irradiated cotton rats from respiratory syncytial virus infection.

Cotton rats (Sigmodon hispidus) that were exposed to 300, 600, or 900 rads of gamma irradiation and inoculated intranasally 2 days later with respiratory syncytial virus (RSV) exhibited prolonged virus shedding and delayed humoral and cytotoxic immune responses compared with comparably inoculated nonirradiated control rats. In nonirradiated animals and in animals exposed to 300 and 600 rads, levels of virus declined and then disappeared from the lungs during the period in which cytotoxic activity was maximal in the lungs of these animals. In contrast, in the group of cotton rats exposed to 900 rads of irradiation, local cytotoxic activity remained low throughout the 11-day observation period, and virus was not eliminated from the lungs. Although virus-neutralizing antibodies in serum and lavage fluids from these animals may have been involved, correlation of antibody concentrations with virus clearance from lungs was not as evident. These data suggest that cytotoxic effector cells have a positive role in eliminating RSV from the lungs of unprimed cotton rats.

Animals↗

Effects of endotoxin and tannin isolated from cotton bracts on the airway epithelium.

The effects of increasing concentrations of tannin isolated from cotton bracts and endotoxin prepared from Enterobacter agglomerans on the electrophysiologic and ion transport properties of the canine tracheal epithelium mounted in Ussing chambers were examined. Results were compared with those obtained using cotton bracts extract (CBE). Tannin concentrations in the isolated tannin and in the cotton bracts were analyzed spectrophotometrically. When added to the mucosal bathing solution, tannin produced a significant decrease in transepithelial potential difference and short-circuit current (lsc) with a maximal response at 25 microliter. The decrease in lsc was accounted for entirely by a decrease in net chloride secretion. The effects were reversible and specific for the mucosal bathing solution. In contrast to CBE, tannin had no effect on mannitol flux, suggesting no effect on the paracellular pathway. Endotoxin at a concentration of 10 micrograms/ml had no effect on the electrophysiologic properties of the canine trachea. We conclude that tannin in CBE is responsible for the decrease in lsc observed with aqueous extracts of CBE but is not responsible for the changes in the paracellular pathway. We also conclude that endotoxin alone has no effect on the airway epithelium.

Animals↗

The relationship between bronchoalveolar neutrophil recruitment and bronchoconstriction induced by a soluble extract of cotton bracts.

Byssinosis is characterized by an obstructive bronchitis in some workers exposed to cotton dust. Mechanisms of airway alterations induced by cotton dust are unknown. To study mechanisms of these alterations, we administered an aqueous extract of cotton bract (CBE) to normal human subjects. After CBE inhalation, we demonstrated reproducible reductions in flow rates of variable magnitude. The percentage of polymorphonuclear leukocytes (PMN) recovered by bronchoalveolar lavage (BAL) and total PMN per milliliter BAL fluid were increased after challenge with CBE, and these parameters were correlated (r = 0.556 and r = 0.553, respectively) with the degree of bronchoconstriction induced by CBE. In addition, chemotactic factors for PMN were noted in BAL fluid and in supernatant from BAL cell cultures. The degree of BAL fluid chemotactic activity correlated with the degree of bronchoconstriction induced by CBE. Assessment of molecular sieve column effluent demonstrated BAL fluid to have 3 distinct peaks of chemotactic activity (approximate molecular weight, greater than 25,000, 10,000, and less than 1,000 daltons) and cell culture supernatant to contain 1 peak (approximate MW, 10,000 daltons). Complement activation as one source of BAL chemotactic activity was suggested by almost complete inhibition of BAL chemotactic activity after incubation with antibody to the fifth component of complement (C5) and detection of C5a des Arg in BAL fluid from some subjects challenged with CBE. These findings suggest that exposure of volunteer subjects to CBE results in a bronchoalveolar inflammatory response related to both complement activation and chemotactic factor synthesis by luminal cells.

Adult↗

Modulation of inflammatory cell function by cotton bract tannin: changes in the capacity of alveolar macrophages and neutrophils to produce hydrogen peroxide.

Inhalation of cotton mill dust leads to the development of the occupational lung disease byssinosis in a portion of the exposed workers. Condensed tannins present in the dust have biologic activities consistent with the hypothesis that they are one of the etiologic agents for the disease. Inhalation of either cotton dust or tannin provokes an acute inflammatory response characterized by the influx of neutrophils into the airways. The secretion of a low-molecular-weight, lipid neutrophil chemotactic factor from the alveolar macrophages in response to tannin stimulation appears to be important in this inflammatory process. In these studies, the effect of tannin the ability of alveolar macrophages and neutrophils to produce hydrogen peroxide was examined. Low concentrations of tannin itself induced a modest production of hydrogen peroxide from conditioned rabbit alveolar macrophages, while higher concentrations failed to induce peroxide production. In the presence of an independent stimulator of peroxide production (concanavalin A), tannin inhibited peroxide production at all concentrations examined. Aqueous extracts of cotton mill dust (CDE) had an identical effect on peroxide production in a manner that indicated that the tannin present in the dust was responsible for the effect. Like its direct effect on macrophage peroxide production, tannin induced modest peroxide production in human neutrophils. However, unlike its effect on macrophages, tannin enhanced the peroxide production induced by the presence of an independent stimulator (phorbol myristate acetate). CDE had a similar effect on peroxide production, but the dose-response curves suggested that only the high-molecular-weight polymers of tannin present in the CDE were able to enhance peroxide production.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Half-life of cotton-wool spots in the acquired immunodeficiency syndrome.

Cotton-wool spots are a hallmark of human immunodeficiency virus (HIV) retinopathy in the acquired immunodeficiency syndrome (AIDS). We analysed the half-life of cotton-wool spots in AIDS in a prospective study, and found the average time to disappearance to be 6.9 weeks. HIV retinopathy differs from diabetic retinopathy in having a smaller size cotton-wool spot and a much shorter half-life, suggesting a patchy involvement of the retinal capillaries in AIDS and a widespread capillary disease in preproliferative and proliferative diabetic retinopathy.

Acquired Immunodeficiency Syndrome↗

Retinal cotton-wool spots as the first sign of systemic sarcoidosis.

Isolated retinal cotton-spots have not yet been reported as the sign of ocular sarcoidosis. We describe three patients with retinal cotton-wool spots of initially unknown etiology in whom systemic sarcoidosis was diagnosed 6-16 months later. The diagnosis was confirmed by conjunctival biopsy. These observations indicate that sarcoidosis should be included in the differential diagnosis of retinal cotton-wool spots and patients with these lesions should be followed for the development of this disease.

Adult↗

Age-dependent replication of respiratory syncytial virus in the cotton rat.

Despite the documented disease burden of respiratory syncytial virus (RSV) in the elderly, little is known about the underlying risk factors or pathogenesis of RSV in a geriatric population. This report describes an age-dependent change of RSV clearance in the lung and nose of the cotton rat. Six days postinfection with RSV, lung and nose viral titers were significantly higher in all older age groups as compared with 4- to 6-week old cotton rats (P < 0.05). When comparing the 4- to 6-week old animals to the 15- to 16-month old animals 6 days postinfection, there was over an 800- and 100-fold increase in lung and nose viral titers, respectively. The cotton rat may prove to be a useful model in eliciting mechanisms of severe RSV disease in the elderly.

Aging↗

Pesticide-handling practices in agriculture in Tanzania: observational data from 27 coffee and cotton farms.

The practices of pesticide handling in agriculture were surveyed in 1991-1993 in Tanzania, to identify hazardous practices and farms where they occurred. The study involved 23 coffee farms with 246 persons exposed to hazardous practices, and four cotton farms with 45 exposed. An observation form addressed locations of important places with respect to pesticide spraying, storage, disposal, and equipment; personal protection; and hygiene. More pesticide formulations were used for coffee compared with cotton and by individual rather than cooperative farms. Coffee farms more often had unlabeled pesticide containers and missing mixing instructions, while cotton pesticides were stored in bedrooms, near food, and near open fires, and pesticide leftovers were often present. Hazardous practices were more pronounced at individual than cooperative farms, with significant differences in pesticide storage areas, as well as unlabeled and non-original containers. The study demonstrated the need to train farmers in pesticide safety, strengthen advisory and regulatory services, and extend protection to farm workers' families.

Agriculture↗

Five points and a lament about Range and Cotton's "Reports of assent and permission in research with children: illustrations and suggestions.

This comment responds to an article by Range and Cotton (1995) on reporting of parental permission and child assent procedures in published articles for 4 psychology journals. Issue is taken with the assumptions, methodology, interpretations, and implications of listing researchers in the Range and Cotton article. There is no evidence researchers failed in their ethical obligations or that children were put at risk. Reporting permission/assent in publications is not an ethical requirement. Listing researchers as "failing" to do something not part of an ethical code is lamentable. Too many unfortunate implications and problems can be derived from Range and Cotton's analysis and conclusions.

Age Factors↗

Take away their hammer: logical and ethical problems in Range and Cotton's "Reports of assent and permission in research with children: illustrations and suggestions.

Range and Cotton (1995) showed that many of the articles reviewed in their study did not include a line specifying institutional review board-approved procurement of informed parental permission and child assent for child research. Range and Cotton stated that the absence of the line suggests a lack of sensitivity to permission/assent issues, implied that many authors of the articles did not obtain permission/assent, and said those who did but did not report it were camouflaging those who did not. In this article, the logic of these points is refuted, the ethics of the Range and Cotton study are questioned, and its potential divisiveness is lamented.

Behavioral Research↗

Gastrointestinal flora of cotton rats.

The gastrointestinal (GI) flora of cotton rats was examined. No lactobacilli were detected in any part of the GI tract. Anaerobes, including Peptococcaceae, Bacteroidaceae, bifidobacteria and eubacteria, were the predominant bacteria in the stomach, small intestine, caecum and faeces. Aerobes and facultative anaerobes, including Enterobacteriaceae and streptococci, were detected at low numbers and very low frequency of occurrence in all parts of the GI tract. Sixty-one isolates of bifidobacteria were recovered from the stomach, small intestine, caecum and faeces of cotton rats. They were identified as Bifidobacterium animalis, B. pseudolongum biovar a and b. The study showed that the GI flora of cotton rats seem to be very different from the GI flora in other rodents.

Animals↗