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At least 127 records · Page 7Linked to original sources

PubMed2000

Maintaining quality of fresh-cut mangoes using antibrowning agents and modified atmosphere packaging.

Treatments to inhibit browning and decay and prolong shelf life of fresh-cut mangoes were investigated. Combinations of antibrowning agents and modified atmosphere packaging (MAP) resulted in a reduction of browning and deterioration of fresh-cut mangoes stored at 10 degrees C. Combinations of several browning inhibitors were more effective than those applied individually. Among these treatments, solutions containing 4-hexylresorcinol (0.001 M) (HR) plus potassium sorbate (0.05 M) (KS) and HR plus KS plus D-isoascorbic acid (0.5 M) (ER) reduced changes in color (L, a, and b) and microbial growth and did not affect sensory characteristics of fresh-cut mangoes. In general, these treatments did not affect significantly the changes in organic acids and sugar content of slices during the 14 days of storage at 10 degrees C. High humidity created in the in-package atmosphere alleviated tissue dryness and was an important factor in the ability of the antibrowning solutions to prevent browning and decay. It appears that the maintenance of quality of fresh-cut mangoes is more related to particular combinations of the antibrowning agents used rather than the modified atmosphere created inside the package. HR + ER + KS treatment in combination with MAP could be used to inhibit browning, decay, and deterioration of fresh-cut mangoes.

Atmosphere↗

PubMed2006

Co-occurrence of the multicopper oxidases tyrosinase and laccase in lichens in sub-order peltigerineae.

BACKGROUND AND AIMS: Following previous findings of high extracellular redox activity in lichens and the presence of laccases in lichen cell walls, the work presented here additionally demonstrates the presence of tyrosinases. Tests were made for the presence of tyrosinases in 40 species of lichens, and from selected species their cellular location and molecular weights were determined. The effects of stress and inhibitors on enzyme activity were also studied. METHODS: Tyrosinase and laccase activities were assayed spectrophotometrically using a variety of substrates. The molecular mass of the enzymes was estimated using polyacrylamide gel electrophoresis. KEY RESULTS: Extracellular tyrosinase and laccase activity was measured in 40 species of lichens from different taxonomic groupings and contrasting habitats. Out of 20 species tested from the sub-order Peltigerineae, all displayed significant tyrosinase and laccase activity, while activity was low or absent in other species tested. Representatives from both groups of lichens displayed low peroxidase activities. Identification of the enzymes as tyrosinases was confirmed by the ability of lichen thalli or leachates derived by shaking lichens in distilled water to metabolize substrates such as L-dihydroxyphenylalanine (DOPA), tyrosine and epinephrine readily in the absence of hydrogen peroxide, the sensitivity of the enzymes to the inhibitors cyanide, azide and hexylresorcinol, activation by SDS and having typical tyrosinase molecular masses of approx. 60 kDa. Comparing different species within the Peltigerineae showed that the activities of tyrosinases and laccase were correlated to each other. Desiccation and wounding stimulated laccase activity, while only wounding stimulated tyrosinase activity. CONCLUSIONS: Cell walls of lichens in sub-order Peltigerineae have much higher activities and a greater diversity of cell wall redox enzymes compared with other lichens. Possible roles of tyrosinases include melanization, removal of toxic phenols or quinones, and production of herbivore deterrents.

Colorimetry↗

PubMed2005

Management of urinary tract infections: historical perspective and current strategies: Part 1--Before antibiotics.

PURPOSE: Urinary tract infections (UTIs) have plagued mankind long before bacteria were recognized as the causative agents of disease and before urology became an established medical specialty. To our knowledge a comprehensive review of the recorded medical history of UTI from its first description in ancient Egyptian papyri through today has not been attempted until now. MATERIALS AND METHODS: Numerous resources were used to collect the information described in this review. Older textbooks from the school of medicine library at our institution were used to collect information on UTI in ancient times. Medical texts from the 19th century contains information regarding the treatment of UTI during that era. Early volumes of the Journal of Urology from the beginning of the 20th century are rich with information on the first attempts at chemotherapy for UTI. MEDLINE searches were used to collect appropriate information after 1969. RESULTS: The Ebers papyrus from ancient Egypt recommended herbal treatments to ameliorate urinary symptoms without providing insight into pathological mechanisms. Hippocrates believed that disease was caused by disharmony of the 4 humors and accordingly diagnosed urinary disorders. Roman medicine further expanded the conservative approach (bed rest, diet, narcotics and herbs) advocated by Greek physicians, while also improving invasive techniques (surgical lithotomy for stones and catheterization for retention). The Arabian physician Aetius refined uroscopy and created a detailed classification and interpretation of urinary disease based on this technique. During the Middle Ages no major advances occurred, although existing therapies were refined and treatments for gonococcal urethritis were well described. The early 19th century provided vivid and detailed descriptions of UTIs without the knowledge that they were caused by microorganisms. Management included hospitalization, bed rest, attention to diet, plasters, narcotics, herbal enemas and douches, judicious bleeding (direct bleeding, cupping and leeches), and surgery for stones, abscess and retention. The discovery of microorganisms as the etiological agents of infectious diseases in general and inflammation associated with urinary diseases in particular provided an impetus for physicians critically to examine management approaches and develop evidence based strategies for UTI treatment. Various antibacterial agents, such as hexamine, mercurochrome and others (hexylresorcinol, methylene blue, pyridium, acriflavin and mandelic acid), showed promise in laboratory studies but their efficacy in clinical investigations was disappointing. CONCLUSIONS: Treatments for UTI until the discovery of antibiotics were largely palliative because the bacterial origin of UTI was not recognized and no specific antimicrobial therapies were available.

China↗

PubMed2001

[Sensitization to resorcinol in a prescription verrucide preparation: unusual systemic clinical features and prevalence].

BACKGROUND: Resorcinol is a rare sensitizer. In Lorraine, where it is used in high concentrations in an anti-wart ointment, this molecule has induced many cases of allergy. The purpose of this study was to describe clinical features in patients sensitized to resorcinol, to determine the incidence of sensitization in Lorraine and ascertain the occurrence of cross reactions with other phenolic pro-haptens. PATIENTS AND METHODS: The files of all patients sensitized to resorcinol were studied from 1992 to 1999. Over a 20-month period, 983 consecutive patients underwent our standard patch tests where we included resorcinol (1 p. 100 in petrolatum). Co-sensitization with other pro-haptens was studied in all sensitized patients. RESULTS: Sensitization to resorcinol was observed in 0.5 p. 100 of the 983 consecutively tested patients. Contact sensitization was found in 24 patients, who all but one had previously used the anti-wart ointment containing resorcinol. All developed contact eczema on the site of application of the ointment, with generalized urticaria (4 cases), pompholyx (1 case), and generalized papulo-vesicular rash with pompholyx (6 cases). Positive patch tests were observed with resorcinol monobenzoate (15/19 cases), pyrocatechol (7/14 cases), pyrogallol (9/19 cases), salicylaldehyde (2/17 cases), and hydroquinone (6/17 cases). Negative patch tests were observed with phenysalicylate, hexylresorcinol, or fluoresceine. CONCLUSION: Resorcinol should not be applied in high concentrations as it can provoke generalized sensitization and co-sensitization with other pro-haptens.

Administration, Cutaneous↗

PubMed1979

Efficacy of inactivators against 14 disinfectant substances.

More than 24 inactivators were tested for their suitability against 14 disinfectant substances by a quantitative suspension test. Even simple inactivators were found to be efficace: 0.1% cysteine and 0.5% sodium thiosulfate for mercuric chloride and the iodophor; 0.1% sodium sulfite for these two substances and for the QAC in the lower concentration; 1.0% polysorbate 80 for hexylresorcinol, o-phenylphenol and the QAC in the lower concentration; 0.5% sodium thioglycolate for mercuric chloride, the iodophor and chloramine-T. The inactivator active against most disinfectants was the combination LPHT or 0.3% lecithin / 3.0% polysorbate 80 /0.1% histidine / 0.5% sodium thiosulfate. Also active were: LPWT (0.5% lecithin / 1.0% polysorbate 80 /1.0% Lubrol W / 1.0% sodium thiosulfate), LPT (2.0% lecithin / 2.0% polysorbate 80 / 0.5% sodium thiosulfate) and PS (3.0% polysorbate 80 / 3.0% saponin).

Disinfectants↗

PubMedDate not supplied

[Synthesis of anabiosis autoinducers in non-spore-forming bacteria as a mechanism regulating their activity in soil and subsoil sedimentary rocks].

Non-spore-forming bacteria of the genera Arthrobacter and Micrococcus, isolated from permafrost subsoil, were found to produce greater amounts of the d1 extracellular factor than closely related collection strains isolated from soil. The effect of this factor, responsible for cell transition to anabiosis, was not species-specific. Thus, the d1 crude preparation isolated from the culture liquid of the permafrost isolate Arthrobacter globiformis 245 produced an effect on the collection strain Arthrobacter globiformis B-1112 and also on Micrococcus luteus and Bacillus cereus. The crude d1 preparation from the permafrost isolate of Arthrobacter differed from the chemical analogue of this factor, 4n-hexylresorcinol, in the level of the induced cell response, which may have resulted from different cell sensitivity to various homologs of alkylhydroxybenzenes contained in the d1 preparation. Thus, additional evidence was obtained indicating that autoregulation of bacterial growth and development is implemented at the level of intercellular interactions in microbial communities. Abundant production of the d1 anabiosis-inducing factors by bacteria isolated from permafrost subsoil is probably a result of special antistress mechanisms responsible for the survival of these bacteria under extreme conditions of natural deep cooling.

Arctic Regions↗

PubMed1976

[Experimental studies on anthelmintics (XXVI). Biochemical and pharmacological studies of 4-iodothymol on Ascaris lumbricoides suum].

We have shown previously that 4-iodothymol (IT) produces a contraction in Ascaris muscle, probably due to the myogenic action. In this paper, the effects of IT on the carbohydrate metabolism in Ascaris muscle have been investigated in comparison with those of hexylresorcinol (Hex), santonin (S) and piperazine (Pip). (1) Hex (200 approximately 400 mug/ml) showed a strong nonspecific inhibition on the formation of succinate from fumarate in muscle homogenate, the phosphofructokinase (PFK) activity in cytoplasm, and the electron transfer activity in mitochondria. (2) S(100 approximately 400 mug/ml) and Pip (100 approximately 400 mug/ml) were inneffective on these activities. (3) IT inhibited the formation of succinate from glucose and fumarate in muscle homogenate (100 approximately 400 mug/ml), the PFK activity in cytoplasm (400 mug/ml), and the mitochondrial succinate oxidase system (25 approximately 400 mug/ml). These results suggest that IT elicits the wormcidal action by inhibiting the energy metabolism of Ascaris muscle mitochondria.

Animals↗

PubMed1963