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Biomedical subjects

A M Adams

Publications and source records attributed to A M Adams.

At least 19 recordsLinked to original sources
PubMed2001

Comparison of patient dose from imaging protocols for dental implant planning using conventional radiography and computed tomography.

OBJECTIVES: To compare the radiation doses from imaging protocols for dental implant planning either using conventional radiography only (dental panoramic radiography (DPR), cephalometry and linear cross-sectional tomography) or involving computed tomography (CT). METHODS: Organ absorbed doses were measured using a female Rando anthropomorphic phantom loaded with lithium fluoride thermoluminescent dosemeters (TLD). Standard mandibular protocols for dental implant planning were followed using either a conventional dental radiographic unit (PM 2002 CC Planmeca, Helsinki, Finland) or CT scanner (Excel Twin Elscint, Haifa, Israel). Organ absorbed and effective doses were calculated. Effective dose was calculated using two approaches, one based on the ICRP method which excludes the salivary tissue from the remainder organs (designated E(exc)), and the other with its inclusion (E(inc)). RESULTS: The greatest individual organ doses for any examination were measured in the salivary tissue. E(exc) for panoramic, cephalometric and cross-sectional tomography using DPR was 0.004 mSv, 0.002 mSv and 0.002 mSv, respectively, whereas with CT it was 0.314 mSv. The value of E(inc) calculated using these data was between two and five times E(exc). CONCLUSIONS: E(inc) greatly increases the apparent radiation burden, especially with high dose procedures. CT techniques can provide excellent images, but at the cost of increased radiation detriment. DPR with a cross-sectional tomography facility may give adequate clinical information at a greatly reduced dose.

Absorption↗
PubMed2001

Evaluation of a new percutaneous dilatational tracheostomy set apparatus.

Percutaneous tracheostomy is a well established technique used primarily to assist weaning from mechanical ventilation on many intensive care units. We report our experiences of a total of 36 procedures performed with the new Blue Rhino Percutaneous Tracheostomy Introducer Set developed by Ciaglia. The technique was successful in all cases and was simpler and quicker to perform than with the earlier Ciaglia percutaneous tracheostomy set. Difficulties were encountered when using Shiley tracheostomy tubes. Significant complications included one posterior wall tear and one tracheal cartilage ring fracture.

Adult↗
PubMed2001

Risk perception and communication: recent developments and implications for anaesthesia.

This review begins by outlining the history of probability theory, exposing cultural differences between scientists and lay people in the way risks are viewed. The basic principles of the science of risk perception are described, and the various methods of communicating risk in health care, both verbal and numerical, are then discussed critically. These concepts are then applied to the practice of anaesthesia. Risk perception may affect anaesthetists' choice of career and may be involved in the genesis and evolution of critical incidents; we also discuss possibilities for training in risk perception issues. The place of risk communication in informed consent and its ethical implications are discussed.

Anesthesia↗
PubMed2000

Gender, socioeconomic development and health-seeking behaviour in Bangladesh.

In efforts to reduce gender and socioeconomic disparities in the health of populations, the provision of medical services alone is clearly inadequate. While socioeconomic development is assumed important in rectifying gender and socioeconomic inequities in health care access, service use and ultimately, outcomes, empirical evidence of its impact is limited. Using cross-sectional data from the BRAC-ICDDR,B Joint Research Project in Matlab, Bangladesh, this paper examines the impact of membership in BRAC's integrated Rural Development Programme (RDP) on gender equity and health-seeking behaviour. Differences in health care seeking are explored by comparing a sample of households who are BRAC members with a sample of BRAC-eligible non-members. Individuals from the BRAC member group report significantly less morbidity (15-day recall) than those from the non-member group, although no gender differences in the prevalence of self-reported morbidity are apparent in either group. Sick individuals from BRAC member households tend to seek care less frequently than non-members. When treatment is sought, BRAC members rely to a greater extent on home remedies, traditional care, and unqualified allopaths than non-member households. While reported treatment seeking from qualified allopaths is more prevalent in the BRAC group, non-members use the para-professional services of community health care workers almost twice as frequently. In both BRAC member and non-member groups, women suffering illness report seeking care significantly less often than men. The policy and programmatic implications of between group and gender differences in care seeking are discussed with reference to the literature.

Adolescent↗
PubMed2000

Natural transfer of helminths of marine origin to freshwater fishes with observations on the development of Diphyllobothrium alascense.

Infective stages of helminths of 5 species that occur as adults in marine mammals were found in burbot, Lota lota (L.) (Gadidae), from the lower Kuskokwim River (southwestern Alaska): Diphyllobothrium alascense Rausch et Williamson, 1958; Pyramicocephalus phocarum (Fabricius, 1780); Corynosoma strumosum (Rudolphi, 1801); Corynosoma semerme (Forsell, 1904); and Pseudoterranova decipiens (Krabbe, 1878). Some larval stages were obtained also from smelt, Osmerus mordax dentex Steindachner, an anadromous fish important as prey of burbot. Burbot, which are freshwater fish, could become paratenic hosts of those helminths by means of at least 3 interactions: by consuming marine fishes in brackish waters at river mouths, by feeding on marine fishes that enter lower reaches of rivers, or by preying on anadromous fishes as they migrate up rivers. Consumption of burbot by people may result in infection by helminths of marine origin; of those recorded, only P. decipiens may be significantly pathogenic. Attempts to rear P. phocarum in dogs were unsuccessful. Plerocercoids of D. alascense, of very small size and found only in the gastric lumen of burbot, readily infected dogs. For study of their development, strobilae were obtained at intervals of 48 hr to 32 days postinfection. In heavy infections, some strobilae developed slowly, while others underwent rapid development.

Acanthocephala↗
PubMed1999

Survival of Anisakis simplex in microwave-processed arrowtooth flounder (Atheresthes stomias).

The purpose of this study was to define the relationship between survival and temperature of nematodes of the species Anisakis simplex in microwave-processed arrowtooth flounder (Atheresthes stomias). Ten fillets (each 126 to 467 g, 0.5 to 1.75 cm thick), with an average of five larvae of Anisakis simplex per fillet, were processed to target temperatures on high (100%) power using a commercial 700-W microwave oven. Fillets were neither covered nor rotated and had a temperature probe inserted to two-thirds depth into the thickest portion. After the fillet was digested using a 1% pepsin solution, the viability of nematodes was determined by viewing them under a dissecting microscope. Survival rates were 31% at 140 degrees F (60 degrees C), 11% at 150 degrees F (65 degrees C), 2% at 160 degrees F (71 degrees C), 3% at 165 degrees F (74 degrees C), and 0% at 170 degrees F (77 degrees C). Microwave processing of standardized fillet "sandwiches," 14 cm long, 4.5 cm wide, and approximately 1.75 cm high, each of which was preinoculated with 10 live nematodes, resulted in no survival at either 160 degrees F or 170 degrees F. Using ultraviolet light to detect both viable and nonviable nematodes in fillet sandwiches as an alternative method to pepsin digestion resulted in survival rates of 1% at 140 degrees F (60 degrees C), 3% at 145 degrees F (63 degrees C), and 0% at 150 degrees F (65 degrees C). Smaller fillet sandwiches, which most likely had fewer cold spots during microwave processing, required 150 degrees F (65 degrees C), whereas larger whole fillets required 170 degrees F (77 degrees C) to kill larvae of Anisakis simplex. The parasites were most likely inactivated by a thermal mechanism of microwave treatment. Damage to the nematodes was often evident from ruptured cuticles that were no longer resistant to digestive enzymes. The high hydrostatic pressure and low chloride content of the pseudocoelomic fluid probably contributed greatly to the damage incurred by the larvae.

Animals↗
PubMed1999

An oligonucleotide-ligation assay for the differentiation between Cyclospora and Eimeria spp. polymerase chain reaction amplification products.

An oligonucleotide-ligation assay (OLA) was developed and compared to a restriction fragment length polymorphism (RFLP) test for distinguishing between 294-bp polymerase chain reaction (PCR) amplification products of the 18S rRNA gene from Cyclospora and Eimeria spp. The PCR/OLA correctly distinguished between three Cyclospora, three E. tenella, and one E. mitis strains and the ratio of positive to negative spectrophotometric absorbance (A490) values for each strain ranged from 4.086 to 15.280 (median 9.5). PCR/OLA provides a rapid, reliable, spectrophotometric alternative to PCR/RFLP.

Animals↗
PubMed1998

Template preparation for PCR and RFLP of amplification products for the detection and identification of Cyclospora sp. and Eimeria spp. Oocysts directly from raspberries.

Raspberries were epidemiologically associated with cyclosporiasis outbreaks during 1996 and 1997. The 18S rRNA genes of Cyclospora cayetanensis and several species of a closely related genus, Eimeria, were sequenced and primers for a nested PCR developed in a previous study. The ability to distinguish amplified products of Cyclospora sp. from those of Eimeria spp. is important for testing food and environmental samples. Therefore, an RFLP analysis of amplified products was used to differentiate Cyclospora cayetanensis from Eimeria spp. PCR inhibitors and the low levels of Cyclospora oocysts present in raspberries make template preparation for PCR challenging. Several approaches for PCR template preparation from raspberry samples were evaluated. Template preparation methods using various washing and concentration steps, oocyst disruption protocols, resin matrix treatment, DNA precipitation, and/or the addition of nonfat dried milk solution to a PCR using modified primers were evaluated first with oocysts of Eimeria tenella then refined with oocysts of C. cayetanensis. Approximately 10 E. tenella oocysts per PCR or approximately 19 C. cayetanensis oocysts per PCR were detected with the optimized template preparation method. The addition of 20 microliters of raspberry wash sediment extract and nonfat dried milk solution did not inhibit the amplification of DNA from as few as 10 E. tenella and 25 C. cayetanensis oocysts in a 100-microliter PCR. The nucleotide sequences of C. cayetanensis and the Eimeria spp. are 94 to 96% similar in the amplified region, but the amplification products from the two genera were distinguished using an RFLP analysis with the restriction enzyme MnlI.

Animals↗
PubMed1998

Occurrence and morphological comparisons of Campula oblonga (Digenea: Campulidae), including a report from an atypical host, the thresher shark, Alopias vulpinus.

New host records for Campula oblonga Cobbold, 1858 from the common dolphin, Delphinus delphis L., and from the thresher shark, Alopias vulpinus (Bonnaterre), are reported herein. Campulids have not been reported previously from a host that was not a marine mammal. The excellent condition and small size of the gravid specimen and the diet and natural history of the thresher shark lead us to conclude that the digene was acquired from the consumption of infected fish. Specimens of C. oblonga from these 2 hosts and from harbor porpoises, Phocoena phocoena (L.), and from Dall's porpoises, Phocoenoides dalli (True), are compared, and a wide variation in ranges and values for characters is noted. The synonymy of Campula folium Ozaki, 1935 with C. oblonga is further supported by the apparent effect of the host on the size of the trematodes. Due to the degree of variation in measurements and the numerous factors that may impact these values, we recommend the use of qualitative morphologic characters for the identification of C. oblonga.

Animals↗
PubMed1997

Parasites of fish and risks to public health.

A multitude of parasites have been reported in fish, but only a few species are capable of infecting humans. The most important of the helminths acquired by humans from fish are the anisakid nematodes (particularly Anisakis simplex and Pseudoterranova decipiens), cestodes of the genus Diphyllobothrium and digenetic trematodes of the families Heterophyidae, Opisthorchiidae and Nanophyetidae. Seafood-associated infections by acanthocephalans are rarely reported in humans. All of the helminths mentioned above are associated with social-cultural and behavioural factors, in particular the consumption of raw or undercooked seafood. Measures can be taken during harvesting, processing or post-processing (e.g., by the consumer) to mitigate the risks of infection. The seafood industry and government authorities can apply various programmes to reduce these risks, including good manufacturing practices (GMPs) and hazard analysis and critical control point (HACCP) systems. Such measures may include avoiding particular harvest areas, sizes of fish, or even particular species of fish. The method of capture, handling and storage of the catch can directly affect the quality of the seafood with regard to the presence and numbers of parasites. The extent of processing--including heading and gutting, candling and trimming--and the type of product derived (fresh, frozen, salted or pickled) can all contribute to the control of the risks posed by helminths. The most effective means of killing the parasites are either freezing or heat inactivation.

Animals↗
PubMed1995

Ultrastructural changes in cultured human periodontal ligament cells exposed to dental materials.

The cytopathic effects of a range of dental restorative cements were examined by electron microscopy using an in vitro model with cultured test cells derived from human periodontal ligament. Monolayers were fixed and processed in situ after 2, 24, and 48 h exposure. Many cells showed lysis after two hours exposure consistent with immediate acute injury. Cultures subsequently recovered, reflecting different susceptibilities of cells to injury, and at later stages showed distinct patterns of cell damage in response to different restorative materials. These were related primarily to either cytoplasmic or nuclear damage and to changes resembling apoptosis.

Apoptosis↗
PubMed1995

Morphological changes in cultured human periodontal ligament cells exposed to dental materials.

The cytotoxicity of a range of dental restorative cements was assessed by continuous observation of cultures with inverted microscopy and by light microscopic study of fixed preparations, using an in vitro model with cultured test cells derived from human periodontal ligament. The sequential morphological changes observed over a seven day period showed different degrees of cell loss and patterns of injury in response to different restorative materials, reflecting primarily either nuclear or cytoplasmic damage. Attempts at recovery were frequently identified as the culture period was extended and were characterized by recolonization of denuded areas of the culture well. It was concluded that differing dental cements damage cells through a variety of mechanisms and that the test cells exhibit differing degrees of susceptibility to injury. Assays based on short-term cultures may overestimate cytotoxicity by not allowing for cell recovery from reversible injury or repopulation of monolayers by proliferation of resistant cells.

Acrylic Resins↗
PubMed1995

Phonological working memory and speech production in preschool children.

This study investigates whether phonological working memory is associated with spoken language development in preschool children. Assessments were made of speech corpora taken from 3-year old children grouped in terms of their phonological memory abilities. Both quantitative and qualitative indices of the children's spontaneous speech output were taken in a structured play session. Significant differences were found, with children of good phonological memory abilities producing language that was more grammatically complex, contained a richer array of words, and included longer utterances than children of poor phonological memory abilities. The possible mechanisms by which phonological working memory skills are linked to the production of speech are considered.

Age Factors↗
PubMed1995

Seasonal variations in energy balance among agriculturalists in central Mali: compromise or adaptation?

OBJECTIVE: This paper considers whether seasonal variations in the energy balance of adult agriculturalists in Central Mali exceed acceptable risk, or whether they represent a short-term adaptive response without functional consequence. DESIGN: Prospective/longitudinal study design. SETTING: Agricultural village in rural Mali. SUBJECTS: From a total population of 166 adults aged > or = 16 years, two cohorts of 63 men and 73 non-pregnant women with complete records were retained for analysis. INTERVENTIONS: Over a 12-month period, monthly anthropometry and biweekly retrospective assessments of morbidity were made on every adult in the sample. Direct measures of household food consumption were collected twice in harvest, dry and rainy seasons respectively. Continuous 15-h observations of time-use and work intensity were conducted on a sub-sample of active adults and used to calculate mean seasonal energy expenditure. RESULTS: Energy balance as measured by body mass index (BMI; kg/m2) declines significantly in the rainy season (P < 0.01), corresponding to a seasonal weight loss of 2-3 kg. A similar seasonal trend in % body fat (P < 0.0001) suggests that most of this loss represents adipose tissue. A rainy season increase in arm muscle area (AMA) implies that there is no seasonal compromise in lean tissue. Among men and women with BMI > 18.5, seasonal fat loss is significantly greater than their leaner counterparts. Considering the likely determinants of variations in energy balance, an increase in the duration and incidence of adult morbidity is observed; however, no significant intercorrelations exist between it and seasonal nutritional indices. Comparing trends in energy expenditure and intake, a disturbance in energy homeostasis is apparent as energy expenditure increases in the rainy season relative to constant household food consumption across seasons. While seasonal variations in energy expenditure are not as dramatic in the female sample, they appear to have less opportunity to recover from so-called 'heavy' levels of expenditure experienced in successive dry and rainy seasons. Periods of 'light' activity in both harvest and dry seasons provide the male sample with a reasonable length of time in which to reconstitute energy stores after the physical demands of the rainy season. CONCLUSIONS: In the year of study, the modest loss of body fat recorded in the rainy season (< 5% body mass) represents a successful physiological response to energy imbalance, and is unlikely to compromise adult productive and reproductive function.

Adaptation, Physiological↗
PubMed1994

Cytotoxicity studies of dental restorative materials using human periodontal ligament cells in vitro.

A model that simulates conditions of clinical practice in vivo and allows extended exposure of test cells to test substances, was evaluated in vitro by screening the toxicity of seven dental restorative cements. Millipore filter discs, 0.45 micron pore size, or preserved dentine slices were used as diffusion barriers between test cells and test substances. Cytotoxicity was assessed by estimating cell loss from monolayers and by evaluating cytopathic changes in cultured cells. After 24 h exposure to the test materials results were in general agreement with reported observations from similar studies. However, extended exposure to composite resins gave rise to severe cytotoxicity, which has not been reported previously. In addition, monitoring of cultures by inverted microscopy demonstrated attempts at recovery in damaged monolayers with viable cells migrating and proliferating into areas of earlier cell loss. This supports observations in vivo of transient pulpal injury associated with the corresponding materials.

Acrylic Resins↗
PubMed1994

Symptomatic and asymptomatic salivary duct abnormalities in Darier's disease: a sialographic study.

Symptoms of obstructive sialadentis have been occasionally reported as a feature of Darier's disease. Parotid sialograms of three patients with confirmed Darier's disease and histories suggestive of salivary obstruction revealed dilatation with periodic strictures and indentations affecting the main ducts. Similar parotid sialograms in three Darier's disease patients with no symptoms attributable to their salivary glands revealed seepage of contrast media associated with the secondary and tertiary ducts. These findings suggest that salivary glands may be more commonly involved in Darier's disease than previous reports indicate.

Adolescent↗
PubMed1994

Do young children rehearse? An individual-differences analysis.

The issue of whether young children rehearse in auditory memory tasks was investigated across a series of three studies comparing individual differences in articulation rates and memory spans. Applying the principles of the working-memory model, children with faster rates of speaking should have superior memory spans if they engage in rehearsal. Two of the experiments, with 4-year-old children, failed to establish any significant association between articulation rate and memory span, although both the memory span and articulation rate procedures were found to be highly reliable in this age group. A third experiment confirmed that, as expected, articulation rates and memory spans were significantly associated with one another in adult subjects. The results indicate that, contrary to recent theories of children's short-term-memory development, 4-year-old children do not engage in subvocal rehearsal during auditory memory span tasks.

Auditory Perception↗