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PubMed1999

[Therapeutic and prophylactic application of TPA (recombinant tissue plasminogen activator) into the anterior chamber of the eye].

BACKGROUND: In therapy-resistant fibrin reactions within the anterior chamber, especially following combined cataract and glaucoma surgery, injection of TPA is indicated. We report our results. PATIENTS AND METHODS: From August 1994 to August 1998 we applied TPA 185 times into anterior chambers. A total of 123 injections were for therapeutic reasons (if local therapy with eyedrops showed no fibrinolytic effect), 32 for prophylactic reasons at the end of operations with intensive manipulation of the iris and following postoperative fibrin risk, and 30 applications for nonfunctional filtering blebs following glaucoma surgery. We applied 10 microg/0.1 ml. RESULTS: On the first day after therapeutic application of TPA, the fibrin was completely dissolved in 61 % of the eyes, and in 36.6 % of the eyes partial fibrinolysis occurred (total 97.6 %). Only 2.4 % of the eyes showed no fibrinolysis. Seventy-five percent of the eyes showed no fibrin reaction within the anterior chamber after prophylactic application of TPA. In all eyes (100 %) we would have expected fibrin reactions. Application of TPA for a filtering blebs disorder after glaucoma surgery resulted in restoration of the filtering bleb function in two-thirds of the eyes. COMPLICATIONS: After 185 applications of TPA into the anterior chamber we saw ten occurrences anterior chamber bleeding (5.4 %). In six eyes (3.2 %) we saw transcient clouding of the corneal endothelium and/or corneal stroma. These complications were reversible, except for irreversible endothelial decompensation in one eye with Fuchs' corneal dystrophy. CONCLUSION: TPA is effective for treating fibrin formation within the anterior chamber and maintaining the function of the filtering bleb. To confirm and quantify the efficiency of prophylactic use, a controlled prospective study is recommended.

Adolescent↗

PubMed2004

Induction of nerve growth factor mRNA in a rat dorsal root ganglion after application of a tourniquet.

We investigated the mRNA levels of neurotrophins and neurotrophin receptors in a rat dorsal root ganglion (DRG), after tourniquet application to a hind limb, to identify the nerve-protective molecules that are induced immediately after peripheral nerve crush and play a part in the process leading to secondary events. No significant expression of nerve growth factor (NGF) mRNA or protein was observed in the control or contralateral DRG. NGF mRNA expression started within 2 h and NGF protein expression was observed in Schwann cells at 4 h after application of the tourniquet, due to termination of the neurotrophin supply from peripheral nerves. The levels of neurotrophin 3 mRNA were significantly increased in the DRGs on both sides at 1 and 2 h after tourniquet application, but no significant changes in brain-derived neurotrophic factor and neurotrophin 4/5 expression levels were observed in either the contralateral or ipsilateral DRG. The expression levels of neurotrophin receptors in the DRGs on both the contralateral and ipsilateral sides had decreased at 1 to 2 h after application of the tourniquet and had returned to the control levels at 4 h after tourniquet application.

Animals↗

PubMed2006

Postoperative application of mitomycin c improves the complete success rate of primary trabeculectomy: a prospective, randomized trial.

BACKGROUND: The intraoperative application of mitomycin c for primary trabeculectomy is associated with potentially sight-threatening side-effects. This study was performed to evaluate the pressure-lowering effect of postoperative application of mitomycin c for primary trabeculectomy and to evaluate the complications of this new technique. MATERIALS AND METHODS: A randomized, prospective clinical trial with 52 consecutive patients scheduled for glaucoma surgery in one large surgical center was performed. Patients underwent routine trabeculectomy. In group 1, mitomycin c (0.05 mg/ml) was applied topically to the filtering bleb for 5 min on the 3 days after surgery (postoperative application). In group 2, no mitomycin c was applied (controls). The IOP values, visual acuity, number of antiglaucomatous medications and complications were evaluated. RESULTS: Follow-up was evaluated up to 24 months for all patients. The mean intraocular pressure decreased from 31.1 to 15.4 mmHg in group 1 and from 24.8 to 15.6 mmHg in group 2 (P=0.79; t-test). The average number of medications decreased from 2.5 and 2.4 to 0.4 and 0.6 (P=0.53; t-test) in groups 1 and 2, respectively. No cases of hypotony maculopathy occurred. An individual decrease of more than 25% of the IOP was present in 84.6% in group 1 and in 53.8% in group 2 (P<0.017). Survival analysis for eyes with a complete surgical success revealed a better outcome of eyes in group 1 as compared to the eyes in group 2 (P<0.013; log-rank test). CONCLUSIONS: To our knowledge, this is the first prospective, randomized clinical trial to evaluate the efficacy of postoperative mitomycin c application in primary trabeculectomy. The application of mitomycin significantly reduced the IOP while not increasing the rate of complications.

Adult↗

PubMed1999

Morphologic proof of the toxicity of mitomycin C on the ciliary body in relation to different application methods.

BACKGROUND: Since postoperative hypotony has been a frequent complication of glaucomatous filtration surgery with adjunctive use of mitomycin C (MMC), the question arises of whether there may be another application method which can minimize this side effect. The purpose of this study was to establish the morphologic side effects of different application methods. METHODS: MMC 0.2 mg/ml was applied to the episclera of nine eyes of six pigmental rabbits at random via collagen shield (CS), soft contact lens (CL), or lyophilisate (20 microg; LY) for 5 min. Two eyes (controls) had a subconjunctival injection of BSS only. Another control eye was left untreated (no injection). No trabeculectomy was performed. One hour later the amounts of MMC in the conjunctiva and aqueous were analyzed by reverse-phase high-pressure liquid chromatography. Ciliary bodies were dissected from the enucleated eyes, embedded and investigated by transmission electron microscopy (TEM). Cell height of the nonpigmented ciliary epithelium was morphometrically assessed by means of computer-assisted image analysis. RESULTS: The light-microscopic analysis of the sectioned cell area revealed reduction of the cell height of the non-pigmented ciliary epithelium (NPCE) after application with soft contact lens (fourfold) and collagen shield (2.5-fold) but not with lyophilisate compared to the untreated eye. The following ultrastructural changes were seen: loss of apical microvilli (CS, CL, LY), disintegrating melanin granules within NPCE (CS), lysis of entire areas with NPCE cells (CS), myelin figures within mitochondria (LY), intracellular vacuoles (CS, CL), lysis of myelinated nerves (CS), myelin figures in mitochondria of endothelial cells (LY), and lysis of stromal fibrocytes (CS). In the control eyes (injection of BSS) none of these ultrastructural changes were detected in the cylindrical NPCE cells. The concentration of mitomycin in the aqueous humor after topical application of MMC on the episclera for 5 min were all below the detection limit (<10 ng/ml). The concentration of MMC in the conjunctiva ranged from 2.1 to 3.7 microg/g. CONCLUSION: Severe morphologic alterations were seen at the electron-microscopic level after application of MMC 0.2 mg/ml with a collagen shield and with a soft contact lens. They were mildest with lyophilisate and absent in the BSS controls. A new administration device is needed if trabeculectomy is to be performed successfully using MMC in human glaucomatous eyes.

Animals↗

PubMed1999

The effectiveness of single and multiple applications of triple dye on umbilical cord separation time.

UNLABELLED: The effectiveness of single and multiple applications of triple dye for umbilical cord care in the umbilical cord separation time (UCST) was evaluated in 180 neonates. Seven neonates were excluded, three where the cord stump separation time was uncertain and four to whom contact was lost. The participating neonates were randomly assigned to two groups. Group 1, 101 neonates, were treated with a regimen of a single application of triple dye. Group 2, 79 neonates, were treated with multiple applications of triple dye. Complete information was obtained from 97 neonates (96.2%) in group 1 and 76 (96%) in group 2. The UCST was 12.6 +/- 0.45 (mean +/- SE) days in group 1 and 16.68 +/- 0.65 days in group 2 (P < 0.0001) and showed no significant association with infants' gender, mode of delivery, gravidity, gestational age, birth weight, or hospital stay. CONCLUSION: A single application of triple dye may be a more favourable regimen with a similarly antimicrobial effect, a shorter UCST and may be more cost effective than multiple applications of triple dye in umbilical cord care.

Anti-Infective Agents↗

PubMed2004

Effects of pneumoperitoneum created through CO2 insufflation and parameters of mechanical ventilation (PEEP application) on systemic dissemination of intraabdominal infections.

BACKGROUND: To examine whether CO2 pneumoperitoneum and positive end expiratory pressure (PEEP) in mechanical ventilation affect the systemic spread of intraabdominal infection. METHODS: Sprague-Dawley male rats weighing 200-300 g were allocated to three groups of 12 animals in each. All rats received mechanical ventilation under general anesthesia. An intraabdominal infection model was established by injecting with 1 ml of Escherichia coli (10(9) CFU/mL) intraperitoneally. Half of the animals in each group were exposed to PEEP (10 cmH2O). CO2 pneumoperitoneum at 13 mmHg was applied to the rats in group 1. Group 2 rats underwent laparotomy. Group 3 served as controls. In addition, TNF-alpha serum levels were measured at baseline and 3 h. A peritoneal specimen for histopathological examination were obtained after the rats were killed at the end of 3 h. For the assessment of data, descriptive statistical methods (mean, standard deviation) as well as Friedman test for repeated measurements in multiple groups, Kruskal-Wallis test for intergroup comparisons, Dunn's multiple comparison test for subgroup comparisons, Mann-Whitney U test for comparisons between paired groups, chi-square and Fisher's exact test for comparison of qualitative data, and McNemar's test for assessment of changes in group variables over time were used. The results were considered statistically significant if probability (p) values were <0.05. RESULTS: Grades of peritonitis in group 1 and 2 were seen to differ nonsignificantly. In group 1, baseline blood cultures were not included in the assessment between the subgroups that received PEEP or not, as there was no growth in any of the subgroups. No significant difference was detected between growth in blood cultures at 1, 2, and 3 h ( p > 0.05). Application of PEEP in subgroups did not alter the blood culture results ( p > 0.05). Significant differences were seen between the initial and final TNF-alpha values of groups (KW: 18.94, p < 0.0001). The values in control group were observed to be significantly lower than those in groups 1 and 2 ( p < 0.01, p < 0.001). Bacteremia and systemic spread of the intraabdominal infection did appear to be different according to the PEEP application. After the assessments of ventilation parameters in our study, significant reductions in pH and HCO3 levels were detected in group 1 as a result of pneumoperitoneum, which was consistent with the literature. There is a significant difference between pH values at baseline and at the end of 1 h because of pneumoperitoneum (Fr: 10.01, p < 0.05). PEEP application in subgroups did not create significant differences in terms of respiratory parameters ( p < 0.01). CONCLUSION: No difference was found between the applications of CO2 pneumoperitoneum and laparotomy with regard to bacteremia and infection-induced peritonitis. It was determined that pneumoperitoneum along with PEEP application had neither a positive nor a negative impact on intraabdominal infection.

Animals↗

PubMed2005

Regulation of synthesis of osteoprotegerin and soluble receptor activator of nuclear factor-kappaB ligand in normal human osteoblasts via the p38 mitogen-activated protein kinase pathway by the application of cyclic tensile strain.

Mechanical stress is thought to play an important role in bone remodeling. However, the correlation between mechanical stress and bone remodeling is poorly understood. In this context, using a model of cyclic tensile strain (CTS) toward human osteoblasts, synthesis of osteoprotegerin (OPG) and soluble receptor activator of nuclear factor-kappaB ligand (sRANKL), and the activation of mitogen-activated protein kinases (MAPKs) were examined. The application of 7%, 0.25-Hz CTS once a day for 4 h for 3 successive days simultaneously caused an increase of OPG synthesis and a decrease of sRANKL release and RANKL mRNA expression in osteoblasts. As for MAPKs activation in osteoblasts with the application of CTS, p38 MAPK was activated 10-20 min after the application of CTS, but extracellular signal-regulated kinase (ERK1/2) and c-Jun NH2-terminal kinase (JNK) were not activated by such application. Furthermore, when CTS was applied once a day for 4 h for 1, 2, or 3 successive days to osteoblasts, p38 MAPK activation was maintained during the 3-day period but ERK1/2 activation was downregulated from day to day, simultaneously. Then, when CTS was applied once a day for 4 h for 3 successive days to osteoblasts pretreated with the p38 MAPK inhibitor SB203580 for 1 h, OPG synthesis was dose-dependently suppressed and inhibition of sRANKL release and RANKL mRNA expression was abrogated. These results indicate that biological responses of OPG and sRANKL synthesis in osteoblasts to the application of CTS are regulated via the p38 MAPK pathway and suggest that CTS might modulate and regulate bone metabolism.

Blotting, Western↗

PubMed2002

Fluoride uptake and distribution in enamel and dentin after application of different fluoride solutions.

The aim of this in vitro study was to examine the fluoride accumulation in enamel and dentin after short- and long-term application of four fluoride solutions, including a casein-based fluoride preparation. Cubical enamel and dentin specimens were cut out from extracted, caries-free, human third molars. The buccal surface of each specimen was moistened for 5 min or 24 h with 10 microl of the control or one of the four test solutions Olaflur, Oleaflur, sodium fluoride, or experimental fluoride containing hydrolyzed casein. The specimens were ground in 20- microm steps and the fluoride content was determined in each enamel and dentin layer. After application of the fluoride solutions, significantly more fluoride was associated with the superficial layer up to 20 microm. The values were 3-4 times higher in enamel and 4-8 times higher in dentin after 5-min application time and 10-24 times higher than the initial fluoride content in both hard tooth tissues after 24-h application time. Focusing on the experimental solution, the fluoride levels in enamel and dentin were somewhere in the order of the values of sodium and amine fluoride solutions. However, a tendency towards higher values could be observed after application of the experimental solution.

Amines↗

PubMed2007

Application of 10 percent formalin for the treatment of radiation-induced hemorrhagic proctitis.

PURPOSE: Rectal instillation of 4 percent formalin solution has been described as a successful treatment for hemorrhagic radiation proctitis recalcitrant to medical treatment. We present our experience with a new method of treatment involving the topical application of 10 percent buffered formalin, which is well tolerated and suitable for office use. METHODS: Patients with marked or refractory rectal bleeding and clinical features consistent with radiation proctitis were reviewed. Treatment involved direct application of a 10 percent buffered formalin solution to the affected mucosa using a 16-inch cotton tip applicator applied through a proctoscope in the office setting. RESULTS: A total of 100 patients with a mean age of 75 (range, 49-91) years were followed for 18 (range, 1-79) months. The interval from radiation exposure to formalin treatment was 21 months. Overall, 93 percent of patients had cessation of bleeding after an average of 3.5 formalin applications at two-week to four-week intervals. Patients with severe (Grade 3) proctitis and those taking aspirin required an average of 1.5 additional treatments. A total of eight patients rebled at a mean of 24 months from treatment; however, all responded to further applications of formalin. Three patients complained of anal pain and one experienced dizziness postprocedure for a complication rate of 1.1 percent. CONCLUSIONS: We present a simple, cost-effective, and well-tolerated method of controlling hemorrhagic radiation proctitis. It is performed by using materials readily available in the office of a colon and rectal surgeon, eliminating the need for bowel preparation, anesthesia, or a surgical suite.

Administration, Rectal↗

PubMed2005

Accelerated degradation of N, N'-dibutylurea (DBU) upon repeated application.

In a recent study on the degradation of N,N'-dibutylurea (DBU), a breakdown product of benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazole carbamate], the active ingredient in Benlate fungicides, degradation half-lives of 1.4-46.5 days were observed across several soils incubated at various combinations of soil moisture potential (-0.03 and -0.1 MPa) and temperature (23, 33, and 44 degrees C) for a single DBU application of 0.08 and 0.8 microg g(-1) (Lee et al. 2004). However, Benlate can be applied as often as every 7 days resulting in the repeated application of DBU likely to be present in the Benlate over a growing season. In this study, the effect of seven repeated DBU applications on mineralization rate was investigated in two soils, which encompass the range in rates previously observed. For the slower degrading soil, repeated DBU application increased mineralization from 0.029 to 0.99 day(-1) at the 0.08 microg g(-1) rate, and 0.037 to 0.89 day(-1) at the 0.8 microg g(-1) rate. For the faster degrading soil, effects on mineralization of repeated DBU applications were small to negligible. For the latter soil, the effect on mineralization of applied DBU concentrations from 0.0008 to 80 microg g(-1) was also investigated. Mineralization rates decreased from 0.43 to 0.019 day(-1) with increasing DBU concentrations. However, the amount of DBU mineralized by day 70 was similar across concentrations and averaged 83% of applied. Microbial respiration was not affected by increasing DBU concentrations. These findings support the supposition that DBU is readily degraded by soil microorganisms, thus unlikely to accumulate in agricultural soils.

Benomyl↗

PubMed2005

Regional delivery of model compounds and 5-Fluorouracil to the liver by their application to the liver surface in rats: its implication for clinical use.

PURPOSE: The purpose of this study was to examine drug distribution in the liver after drug application to the rat liver surface. METHODS: Phenolsulfonphthalein (PSP) and fluorescein isothiocyanate dextran (MW 4400, FD-4) as model compounds or 5-fluorouracil (5-FU) was applied to the rat liver surface by employing a cylindrical diffusion cell (i.d. 9 mm, 0.64 cm2). Then, blood and the remaining solution in the diffusion cell were collected at selected times, followed by excision of the liver. The excised liver was divided into three sites: the region under the diffusion cell attachment site (site 1), the applied lobe except for site 1 (site 2), and non-applied lobes (site 3). RESULTS: In the case of i.v. administration, there were no differences in PSP concentrations among the three sites of the rat liver, and the concentrations rapidly decreased. On the other hand, the PSP concentration in site 1 after application to the rat liver surface was considerably higher than in site 2 and site 3. In addition, the area under the curve (AUC) value (AUCsite1), calculated from the PSP concentration profile in site 1, was about 10 times larger than that in site 3. A similar trend of regional delivery advantage by liver surface application was observed in the case of the macromolecule model FD-4, with a marked AUCsite1 of about 5 times larger than the other two sites. Moreover, we clarified that the anticancer drug 5-FU preferentially distributed in site 1 after application to the rat liver surface. CONCLUSION: These results demonstrate the possibility of regional delivery of drugs to the liver by application to the liver surface.

Absorption↗

PubMed1984

Effects of iontophoretic application of convulsants on the sensory responses of neurons in the brain-stem reticular formation.

Iontophoretic or pneumatic application of convulsants produced enhancement of the sensory responses of brain-stem reticular formation (RF) neurons in cat and rat. Enhanced sensory responsiveness is observed with visual, auditory, somatosensory and vibrissa manipulation following application of strychnine, bicuculline or pentylenetetrazol. The effect was not transmitter-specific, since it could be produced by sequential application of bicuculline and strychnine which are thought to affect different neurotransmitters. Intravenous administration of convulsant also enhanced the responsiveness of RF neurons which had previously been affected by application of a different convulsant. Both systemic and iontophoretic effects could be antagonized by application of GABA and glycine. These data, coupled with previous findings in primary sensory pathways, indicate that sensory response enhancement in the RF induced by intravenous administration of these convulsants is in large part due to actions on synaptic elements of reticular formation neurons.

Animals↗

PubMed1994

International Commission for Protection Against Environmental Mutagens and Carcinogens. Application of SAR methods to non-congeneric data bases associated with carcinogenicity and mutagenicity: issues and approaches.

In both industry and government, structure-activity relationships (SAR) are capable of playing an important decision-support role in estimating the potential mutagenicity or carcinogenicity of chemicals for which bioassay test results are unavailable. Traditional SAR modeling approaches, however, are usually restricted to the consideration of structurally similar chemical congeners. The highly structurally diverse nature of current carcinogenicity and mutagenicity data bases has motivated development of more general SAR approaches, potentially applicable to the treatment of diverse, non-congeneric mutagenicity and carcinogenicity data bases. Three specific approaches are considered in some detail--Ashby's structural alerts model, classified as a "rule-based" SAR approach, and the computerized CASE fragment-based method and TOPKAT linear discriminant equation method, both classified as "correlative" SAR approaches. Relative strengths and limitations, and a number of common features and important distinctions between these 3 methods are discussed. Rule-base methods are highly flexible and able to incorporate many different types of relevant information, yet are biased towards current knowledge, viewpoints, and mechanistic assumptions, that may or may not hold true. Correlative SAR methods are less biased and offer the promise of "discovering" potentially new SAR associations that could lend fresh insight into the basis for a structure-activity association. However, problems associated with their application to non-congeneric data bases relate to: modeling multiple or overlapping mechanisms of action with a single relationship; defining the range of applicability of models in complex multi-dimensional structure-activity space; assigning confidence levels to predictions in the absence of knowledge concerning mechanisms of activity; and determining the potential mechanistic significance of diverse model parameters. It is argued that many of these concerns can be partially alleviated by careful application of statistical procedures, scrutiny of model results, and establishment of reasoned limits to the range of model applicability. The most significant confidence-building measure, however, will be a rationalization of the correlative SAR model and model parameters in terms of principles of chemical reactivity and postulated molecular mechanism(s) for the biological activity. Hence, it is recommended that models and model descriptors be designed to facilitate mechanistic interpretation and hypothesis generation. Finally, problems in comparing the relative predictive capabilities of different SAR approaches are discussed, and strategies for SAR investigation involving integration of existing techniques are suggested.

Animals↗

PubMed1984

Acute effect of DMBA application on Langerhans cells of the hamster buccal pouch mucosa.

One, two, and three applications of DMBA in mineral oil to hamster buccal pouch mucosa did not result in obvious histologic alterations in experimental periods ranging from 4 1/2 hours to 2 weeks after the last DMBA application. However, there were significant increases in the number of Langerhans cells, as disclosed histochemically with ATPase staining. There was also an increase in the length and size of the dendritic processes of the Langerhans cells. Applications of DMBA in oil resulted in a consistently significant increase in Langerhans cells when compared to the buccal pouch mucosa of untreated animals. However, mineral oil applications also resulted in a slight increase in Langerhans cells when compared to the mucosa of untreated controls. The major effects of the DMBA on Langerhans cells occurred after 2 weeks and with increasing numbers of applications. The increase in Langerhans cells is interpreted as an enhanced response by immunologically competent cells which may represent an early immune response to the very early changes in carcinogenesis.

9,10-Dimethyl-1,2-benzanthracene↗

PubMedDate not supplied

Medical and surgical applications of space biosensor technology.

Researchers in space life sciences are rapidly approaching a technology impasse. Many of the critical questions on the impact of spaceflight on living systems simply cannot be answered with the limited available technologies. Research subjects, particularly small animal models like the rat, must be allowed to function relatively untended and unrestrained for long periods to fully reflect the impact of microgravity and spaceflight on their behavior and physiology. These requirements preclude the use of present hard-wired instrumentation techniques and limited data acquisition systems. Implantable sensors and miniaturized biotelemetry are the only means of capturing the fundamental and critical data. This same biosensor and biotelemetry technology has direct application to Earth-based medicine and surgery. Continuous, on-line data acquisition and improved measurement capabilities combined with the ease and flexibility offered by automated, wireless, and portable instruments and data systems, should provide a boon to the health care industry. Playing a key role in this technology revolution is the Sensors 2000! (S2K!) Program at NASA Ames Research Center. S2K!, in collaboration with space life sciences researchers and managers, provides an integrated capability for sensor technology development and applications, including advanced biosensor technology development, spaceflight hardware development, and technology transfer and commercialization. S2K! is presently collaborating on several spaceflight projects with dual-use medical applications. One prime example is a collaboration with the Fetal Treatment Center (FTC) at the University of California at San Francisco. The goal is to develop and apply implantable chemical sensor and biotelemetry technology to continuously monitor fetal patients during extra-uterine surgery, replacement into the womb, through birth and beyond. Once validated for ground use, the method will be transitioned to spaceflight applications to remotely monitor key biochemical parameters in flight animals. Successful application of NASA implantable biosensor and biotelemetry technologies should accelerate the advancement of this and other modern medical procedures while furthering the exploration of life in space.

Aerospace Medicine↗

PubMed1995

Protective measure use and symptoms among agropesticide applicators in Sri Lanka.

Sri Lankan farmers use large amounts of pesticides to control the pests affecting their vegetable crops. Improper use of pesticides by farmers has resulted in poisoning of occupational origin. This paper examines the use of protective measures by pesticide applicators and its relationship to their illness symptoms. The data were collected by interviewing a stratified random sample of 150 farmers from predominantly vegetable growing areas of the Matale district during 1990/91 using structured questionnaires. These data were supplemented with secondary data and observation of all stages of pesticide application. Scales were constructed to measure the domains of material style of life, awareness and use of protective measures, and illness symptoms experienced by pesticide applicators. It was found that most of the farmers were aware of the protective measures to be used when applying pesticides. There was, however, no significant positive relationship between awareness and use of protective measures. The main reason for not using protective measures was discomfort. The most common symptoms reported by pesticide applicators were faintish feeling, headache and dizziness. A significant negative relationship was observed between use of protective measures and symptoms exhibited within four hours of application. It is recommended that protective materials adapted to the climate and socio-economic conditions of farmers be developed, and that farmers be encouraged to use these protective materials through appropriate educational efforts and incentives.

Adult↗

PubMed1991

Metabolism of aldrin to dieldrin by rat skin following topical application.

Metabolism of the pesticide aldrin to dieldrin in the rat was studied following topical and ip administration of 0.1-10 mg aldrin/kg body weight. When aldrin was applied topically to the dorsal skin at a dose of 10 mg/kg body weight, absorption was less efficient than after ip administration; lower blood levels of aldrin and dieldrin were seen and peak dieldrin levels were delayed. After ip administration of 1 or 10 mg aldrin/kg body weight, dieldrin was found at similar concentrations in the dorsal and ventral skin 7 hr later, whereas 7 hr after topical administration of 10 mg aldrin/kg, the dieldrin concentration in the skin at the dorsal site of application was four times higher than that at a ventral skin site. Similar differences in dieldrin concentrations between dorsal and ventral skin persisted throughout the 7-hr period following topical application. The results indicate that topically applied aldrin is metabolized to dieldrin in the skin during absorption, but the overall proportion of metabolism that takes place in the skin is small compared with the contribution of the liver. Dieldrin was not detected in the ventral skin remote from the application site 1 hr after topical application of aldrin, whereas a dieldrin concentration of 2.2 nmol/g was detected in the skin of the application site at this time; more than 99% of this dieldrin was probably formed locally by dermal metabolism of percutaneously absorbed aldrin. The efficiency of conversion of applied aldrin to dieldrin decreased with increasing aldrin dose in the range 0.1 to 10 mg/kg.

Administration, Topical↗

PubMedDate not supplied

The carcinogenic response in mice to the topical application of propane sultone to the skin.

The carcinogenic effects of limited and repeated skin applications of propane sultone were investigated in three strains of mice, CF1, C3H and CBah (a hairless strain). Propane sultone was shown to be carcinogenic when given as a single application of a 25% w/v solution in toluene and also following twice weekly application of a 2.5% w/v solution for up to 58 weeks. More limited exposure to 2.5% w/v solutions of propane sultone resulted in a few skin tumours, although the incidences were not statistically significant. Most neoplasms were papillomas or carcinomas, although a small number of mesenchymal tumours of dermal origin also developed. No skin neoplasms were found in any control mice. The skin application of propane sultone was associated with a statistically significant increase in the incidence of systematic neoplasia in CFl and C3H mice. The exposed CFl mice had a higher incidence of neoplasms of lymphoreticular and lung origin, while female C3H mice showed a higher incidence of mammary gland and uterine tumours. In mice exposed to beta-propiolactone as a positive control, neoplasms developed at the site of application but, there was no evidence of increased systemic neoplasis in contrast to the findings with ptopane sultone.

Animals↗