Biomedical subjects
Publications and source records attributed to M K Moore.
Onychocola canadensis is an uncommon nondermatophyte mould which can occasionally cause onychomycosis, and rarely, tinea manuum. It typically affects elderly individuals, some of whom have been farmers, in temperate climates. We describe a patient with onychomycosis due to this organism. She failed to respond to a 12-week course of terbinafine 250 mg o.d.
Many aspects of sea turtle biology are difficult to measure in these enigmatic migratory species, and this lack of knowledge continues to hamper conservation efforts. The first study of paternity in a sea turtle species used allozyme analysis to suggest multiple paternity in loggerhead turtle (Caretta caretta) clutches in Australia. Subsequent studies indicated that the frequency of multiple paternity varies from species to species and perhaps location to location. This study examined fine-scale population structure and paternal contribution to loggerhead clutches on Melbourne Beach, FL, USA using microsatellite markers. Mothers and offspring from 70 nests collected at two locations were analysed using two to four polymorphic microsatellite loci. Fine-scale population differentiation was not evident between the sampled locations, separated by 8 km. Multiple paternity was common in loggerhead nests on Melbourne Beach; 22 of 70 clutches had more than one father, and six had more than two fathers. This is the first time that more than two fathers have been detected for offspring in individual sea turtle nests. Paternal genotypes could not be assigned with confidence in clutches with more than two fathers, leaving the question of male philopatry unanswered. Given the high incidence of multiple paternity, we conclude that males are not a limiting resource for this central Florida nesting aggregate.
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We report a case of eumycetoma due to Madurella mycetomatis affecting the left dorsal forefoot in a 35-year-old woman. She had spent her childhood in Jamaica, and had been resident in the U.K. for 20 years prior to her presentation. She gave a highly suggestive history for a mycetoma, having observed the intermittent discharge of black grains from the lesion. The diagnosis was confirmed by histological and mycological analysis of the grains, and a magnetic resonance imaging scan excluded osteomyelitis. She has responded very favourably to treatment with itraconazole. Mycetomas due to M. mycetomatis have not previously been reported from Jamaica.
A survey of tinea capitis conducted under the auspices of the European Confederation of Medical Mycology showed that laboratories contributing to a voluntary scheme for reporting have recently been seeing a different pattern of scalp ringworm. The survey was conducted among 92 medical mycology laboratories across 19 European countries by postal questionnaire comparing the years 1987 with 1997. The survey shows an overall increase in the numbers of cases caused by anthropophilic infections, which, in 1997, were the dominant causes of scalp infection; the greatest increase was seen in laboratories covering urban populations and in African Caribbean children living in Europe. While the commonest infection remains Microsporum canis, the largest overall increase has been in Trichophyton tonsurans, which in 1997 was the second commonest cause of infection overall and the commonest in urban populations. The pattern of change is not uniform in Europe and while some cities have reported large increases in T. tonsurans others, e.g. in France, have seen more cases of infection due to T. soudanense and M. audouinii. While these figures do not necessarily reflect changes in the underlying prevalence of infection, the trends are important to recognize as the control measures for anthropophilic tinea capitis differ from those used in zoophilic infections. In particular there is a need for an increased level of surveillance and more advice on control given to primary care physicians, dermatologists and school health authorities.
We have tested 508 strains belonging to 24 species of dermatophytes against 10 antifungal drugs following mainly the NCCLS (M38-P) standard for filamentous fungi. However, several important factors, such as the temperature (28 versus 35 degrees C) and time of incubation (4 to 10 days versus 21 to 74 h), have been modified. The antifungals used were itraconazole, ketoconazole, miconazole, clotrimazole, voriconazole, terbinafine, amphotericin B, fluconazole, UR-9825, and G-1. In general, with the exception of fluconazole and G-1, all antifungals were shown to be highly effective.
Oxidative modification of human low-density lipoprotein (LDL) renders it atherogenic. Previous studies demonstrated that plasma thiols promote oxidation of LDL by free ferric iron (Fe3+). The current study investigated effects of plasma thiols on oxidation of LDL by hemin, a physiological Fe3+-protoporphyrin IX complex thought to be capable of initiating LDL oxidation in vivo. In contrast to free Fe3+ which is incapable of oxidizing LDL in the absence of an exogenous reductant, hemin readily promoted LDL oxidation. During incubation of LDL (0.2 mg of protein/ml) with hemin (10 microM) at 37 degrees C for 6 h, thiobarbituric acid-reactive substances (TBARS), a marker of lipid oxidation, increased from 0.3 (+/-0.1) nmol/mg of LDL protein to a maximal concentration of 45.8 (+/-5.2) nmol/mg of LDL protein. Under the same experimental conditions, lipid-conjugated dienes, another marker of lipid oxidation, increased from non-detectable to near-maximal levels of 78-187 nmol/mg of LDL protein, and lipoprotein polyunsaturated fatty acyl-containing cholesteryl ester content decreased to 15-36% of that present in native (i.e. unoxidized) LDL. Continued incubation of LDL with hemin for up to 24 h resulted in no further significant alterations in lipoprotein levels of TBARS, lipid-conjugated dienes, and cholesteryl esters. In addition to these chemical modifications indicative of lipoprotein oxidation, agarose gel electrophoretic analysis indicated that exposure of LDL to hemin resulted in conversion of the lipoprotein to an atherogenic form as evidenced by its increased anodic electrophoretic mobility. Addition of physiological concentrations of plasma thiols (either cysteine, homocysteine or reduced glutathione; 1-100 microM, each) inhibited hemin-mediated oxidation of LDL. Thus, whereas the maximal TBARS concentration was achieved following 6 h of incubation of LDL with hemin alone, addition of thiol extended the time required to attain maximal TBARS concentration to > or = 12 h. Similar antioxidant effects of thiols on formation of lipid-conjugated dienes, loss of cholesteryl esters, and lipoprotein anodic electrophoretic mobility were also observed. However, all thiols were not equally effective at inhibiting hemin-dependent LDL oxidation. Thus, whereas reduced glutathione was most effective at inhibiting hemin-dependent LDL oxidation, an intermediate effect was observed for homocysteine, and cysteine was least effective. The inhibition of hemin-mediated LDL oxidation by plasma thiols reported here confirms a previous observation that, under certain conditions, thiols can function as antioxidants, but contrasts with the previously documented pro-oxidant effect of the same thiols on oxidation of LDL by free Fe3+. These contrasting effects of plasma thiols on hemin- and free Fe3+-mediated LDL oxidation indicate that, in vivo, the ability of thiols to function as either anti- or pro-oxidants during LDL oxidation may, at least in part, be determined by the type of oxidant stress to which the lipoprotein is exposed.
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We previously demonstrated a correlation between wild-type p53 expression and appearance of osteoblastic-specific differentiation characteristics, as evidenced by basal osteocalcin gene expression in a mouse osteosarcoma tumor. The study reported here further explored the possibility of p53's having a distinct transcription-activating role in bone differentiation, in addition to its proposed role in G1 arrest and apoptosis. ROS17/2.3 osteoblastic osteosarcoma cells were stably transfected with a plasmid containing wild-type p53 binding sequences fused to the chloramphenicol acetyltransferase reporter gene. These cells were used to determine the transactivating role of p53 in regulation of osteocalcin gene expression. We chose two conditions under which osteocalcin expression is known to be upregulated: exposure of osteoblastic cells to differentiation-promoting medium and to vitamin D3. Exposure of the transfected cells to differentiation-promoting medium produced an increase in p53 transactivating activity correlating with the appearance of osteocalcin expression after about 1 wk. Vitamin D3 treatment resulted in upregulation of osteocalcin activity without a corresponding change in p53 transactivation activity or expression. In separate experiments, we tested whether changes in osteocalcin expression accompanied changes in p53 activity under conditions of downregulation of cell proliferation mediated by inhibition of DNA synthesis. Hydroxyurea treatment was used to inhibit DNA synthesis and produce growth arrest in osteoblastic cells. Inhibition of osteoblast cell proliferation was associated with a fourfold increase in p53 transactivating activity and a transient increase in osteocalcin steady-state expression. These results demonstrated a close relationship between p53 and osteocalcin and suggested a regulatory role for wild-type p53 in the control of basal osteocalcin gene expression in osteoblasts.
We describe a healthy young woman with a localized deep dermal infection on the right side of the chest wall. It was caused by the dermatophyte Trichophyton mentagrophytes, and resolved after two pulses of oral itraconazole 200 mg twice daily for 1 week. As cultural and microscopic features did not enable a precise identification of the fungus, molecular investigation was undertaken. Patterns of HaeIII restriction digests of genomic DNA from the culture matched those from Arthroderma incurvata and A. benhamiae, which is the teleomorph of T. mentagrophytes var. mentagrophytes.
A cryopreservation method and improved isolation techniques for detection of Pasteurella multocida from wetland samples were developed. Wetland water samples were collected in the field, diluted in dimethyl sulfoxide (DMSO, final concentration 10%), and frozen at -180 C in a liquid nitrogen vapor shipper. Frozen samples were transported to the laboratory where they were subsequently thawed and processed in Pasteurella multocida selective broth (PMSB) to isolate P. multocida. This method allowed for consistent isolation of 2 to 18 organisms/ml from water seeded with known concentrations of P. multocida. The method compared favorably with the standard mouse inoculation method and allowed for preservation of the samples until they could be processed in the laboratory.
Cause of mortality was studied in waterfowl in hypersaline playa lakes of southeast New Mexico during spring and fall migration. Mortality was not common in wild ducks resting on the playas during good weather. However, when birds remained on the lakes for prolonged periods of time, such as during experimental trials and stormy weather, a heavy layer of salt precipitated on their feathers. Sodium toxicity was the cause of death for all experimental mallards housed on playa water and for 50% of the wild waterfowl found moribund or dead during the spring of 1995. Gross lesions included heavy salt precipitation on the feathers, ocular lens opacities, deeply congested brains, and dilated, thin-walled, fluid-filled cloacae. Microscopic lesions in the more severely affected birds included liquefaction of ocular lens cortex with lens fiber swelling and multifocal to diffuse ulcerative conjunctivitis with severe granulocytic inflammation, edema, and granulocytic vasculitis resulting in thrombosis. Inflammation similar to that seen in the conjunctiva occasionally involved the mucosa of the mouth, pharynx, nasal turbinates, cloaca, and bursa. Transcorneal movement of water in response to the hypersaline conditions on the playa lakes or direct contact with salt crystals could induce anterior segment dehydration of the aqueous humor and increased osmotic pressure on the lens, leading to cataract formation.
The increasing prevalence of onychomycoses, along with the wider range of organisms now recognized as potential pathogens, necessitates the accurate laboratory identification of the specific fungus involved. Although the majority of infections still are caused by dermatophyte and Candida species, many other nondermatophyte molds, such as Scytalidium dimidiatum, have been shown to be common agents of disease in certain geographic areas. It is well recognized that infections by nondermatophytes such as Scopulariopsis, Acremonium, and Aspergillus species occur worldwide. The availability of a range of new antifungal agents with various spectra of activity means that the exact identification of the pathogen is necessary to select the optimum treatment.
Cases of onychomycosis represent up to 30% of diagnosed superficial fungal infections and are caused by three groups of fungi: dermatophytes, yeasts, and nondermatophytic molds. The majority of toenail infections are caused by dermatophytes; Trichophyton rubrum is isolated with the greatest frequency. In infections of fingernails, Candida species can be isolated as frequently as the dermatophytes. Of the molds, Scytalidium species can infect both fingernails and toenails, as well as adjacent skin, and represent 3% of the nail infections in a temperate country such as the United Kingdom but a much higher proportion in tropical countries. Other molds such as Scopulariopsis, Acremonium, and Aspergillus species can infect damaged nails. The isolation of a dermatophyte is always considered indicative of infection, but the presence of other molds, which may be aerial contaminants, must be interpreted with care.
Tinea nigra is a clinically distinctive superficial mycosis of the palms, and occasionally the soles, caused by Phaeoannellomyces werneckii. A patient, resident in the United Kingdom, is described who acquired the infection in Thailand. The condition cleared after treatment with topical miconazole cream 2%.
Control is a key issue for patients with amyotrophic lateral sclerosis, and caring for them in their own homes is often an essential part of remaining in control. This goal can usually be achieved if all resources are correctly used.
Characteristics of clinically diagnosed cases of tinea capitis from Trinidad are described. Tinea capitis comprised 29.5% of all dermatophytoses seen at one general hospital out-patient dermatology clinic during a one-year period. Males were more often affected than females and there was a predominance of patients of African descent. Among the dermatophytes cultured Trichophyton tonsurans was the most prevalent (52.9%), followed by Microsporum canis (20.0%) and M. audouinii (18.6%). Less frequent isolates included M. gypseum (1.9%), T. mentagrophytes var granulare (1.4%) and T. rubrum (1.4%).
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