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Biomedical subjects

D Kay

Publications and source records attributed to D Kay.

At least 55 records · Page 3Linked to original sources

Plantar fasciitis. Mechanics and pathomechanics of treatment.

An excessive amount and/or a prolonged duration of pronation is the most common mechanical cause of structural strain resulting in plantar fasciitis. Temporary relief of pain can be achieved by customary antiinflammatory drugs or therapy; long-term relief is achieved by adequate remedy of the aggravating pronation factors. A semirigid, custom-molded orthosis reduces excessive plantar fascial strain by supporting the first metatarsal bone and by controlling calcaneal position when in conjunction with a firm posterior counter shoe. A clinical environment with physician and orthotist together allows ideal evaluation and treatment of patients.

Fasciitis↗

Primary lymphoma of the central nervous system in children with acquired immunodeficiency syndrome.

Three children with acquired immunodeficiency syndrome and primary lymphoma of the CNS are described. All three children had clinical signs of focal mass lesions and progressive neurologic deficits. In one child the deterioration was extremely rapid. New lesions appeared on serial CT scans every few days, simulating an infectious process and leading to death within 3 weeks. Results of neuroradiologic studies in these patients demonstrated multicentric lesions that were often periventricular. On CT scans, the lesions were hyperdense before contrast and were enhanced with contrast medium. Double-dose delayed contrast CT scans and magnetic resonance imaging studies were more sensitive in indicating additional lesions. Histologically, all three tumors were B cell neoplasms; two lymphomas were large cell type, whereas one was small cell, noncleaved (Burkitt-like). Primary CNS lymphoma occurred with an incidence of 1/26 (4%) in our autopsy series and 3/100 (3%) of all pediatric cases of human immunodeficiency virus-type 1 infection, living and dead, that have been seen at the Children's Hospital of New Jersey. By comparison, opportunistic and reactivated latent CNS infections were less common in this same population and never appeared clinically as mass lesions. Therefore, in our experience, primary lymphoma is the most common cause of focal or multifocal mass lesions in the brains of children with acquired immunodeficiency syndrome. This tumor may be radiosensitive. In most cases, early biopsy is probably necessary to establish the diagnosis.

Acquired Immunodeficiency Syndrome↗

Pain in rheumatoid arthritis: relationship to demographic, medical, and psychological factors.

Our purpose was to investigate the relationship among demographic, medical, and psychological factors and self-reported pain in 135 patients with classic or definite rheumatoid arthritis (RA). Patients were examined using the systemic index, articular index, McGill Pain Questionnaire, Symptom Checklist-90-R, and a pain visual analogue scale. Multiple regression analyses found no significant relationships between pain and the medical variables. However, age, income, and selected psychological variables were significantly correlated with pain reports. The greatest pain management challenge occurred in patients who were middle-aged, living on limited incomes, and experiencing major stresses in everyday life. These high risk pain patients were also worry-prone and felt isolated and lacking in social support. Attention to these related psychosocial problems is recommended as an important pain management strategy in RA.

Arthritis, Rheumatoid↗

A malaria protein exported into a new compartment within the host erythrocyte.

A Plasmodium falciparum protein which is exported into a new compartment in the host erythrocyte has been located. This protein, exp-1, has a variable region recognized by a monoclonal antibody. Naturally occurring mutants of this region have been characterized. All mutants studied so far have the same A----G transition abolishing the target for the antibody. The exp-1 gene has a complex structure containing two introns. It is highly conserved in five independent, genetically defined parasite lines, suggesting that exp-1 has an important function. We discuss the possible role of exp-1 in P. falciparum infections.

Amino Acid Sequence↗

The head-tail linker protein of bacteriophage T5: genetic and immunological studies.

We investigated the properties of amber mutants of coliphage T5 defective in a late stage of phage assembly. The non-functional heads synthesized by mutants am25 or am158 were unable to combine with functional tails to produce viable phage particles. These mutants were shown to lack a single protein, designated the head-tail linker protein (HTLp), which was identified by polyacrylamide gel electrophoresis and Western blot analysis and had an Mr of 18,000. An extract containing the HTLp, when added to the HTLp-deficient heads, restored their ability to combine with functional tails.

Electrophoresis, Polyacrylamide Gel↗

The characterization of a set of amber mutants of bacteriophage T5.

A collection of amber mutants of bacteriophage T5 was analysed using an in vivo complementation test and assigned to 21 complementation groups. The incomplete phage structures produced by T5 amber mutant infection of the non-permissive host were examined. The mutants were allocated to four phenotypic types, as defined by an in vitro complementation test: those which produced functional heads, H; those which produced functional tails, T; those which produced inactive heads and functional tails, HI + T; and those which did not synthesize either heads or tails, 0. Functional heads and inactive heads were indistinguishable in shape and size in the electron microscope. Four different patterns of DNA metabolism were observed when different amber mutants were grown under non-permissive conditions. They were the wild-type pattern (D+) in which host DNA degradation was followed by synthesis of phage DNA, host DNA degradation without phage DNA synthesis (D0), neither host DNA degradation nor phage DNA synthesis (DD0) and host DNA degradation with slight DNA synthesis (DS). Upon infection of the non-permissive host with representatives of different complementation groups of mutants either normal lysis occurred or bacterial growth ceased without subsequent lysis. The phenotypic characteristics of the amber mutants were used for partial elucidation of the functions of the affected genes.

Bacteriolysis↗

Sonographic characterization of carotid plaque: detection of hemorrhage.

By careful evaluation of the sonographic characteristics of carotid plaques, two patterns can be identified: a homogeneous pattern containing uniform echoes corresponding to dense fibrous tissue and a heterogeneous pattern containing mixed echoes and anechoic areas that represent intraplaque hemorrhage pathologically. A prospective study was conducted of 50 patients to determine the accuracy of identifying these different forms of plaque. The patients' carotid arteries were examined by a high-resolution duplex scanner before carotid endarterectomy. The plaques were evaluated carefully by vascular surgeons and pathologists for the presence of intraplaque hemorrhage. In this study, the accuracy of identifying the presence or absence of intraplaque hemorrhage with sonography was 90% (48 of 54); sensitivity, 94% (17 of 18); and specificity, 88% (27 of 31). High-resolution sonography appears to be an accurate means of identifying intraplaque hemorrhage and may ultimately be useful in identifying patients at risk for embolic disease.

Aged↗

In-vitro fertilisation of oocytes from women with serum antisperm antibodies.

Five women whose infertility was believed to be related primarily to their serum antisperm antibodies underwent in-vitro fertilisation and embryo transfer. Follicle growth was stimulated with clomiphene citrate, sometimes combined with human menopausal gonadotropin, and ovulation was triggered off with human chorionic gonadotropin. 20 oocytes were collected from the five patients, and 15 of these were fertilised in the presence of donor serum. All embryos developed to morphologically normal 2-cell and 4-cell embryos. All five women proceeded to embryo transfer, and two became pregnant.

Antibodies↗

Catalase and superoxide dismutase in Escherichia coli.

We assessed the roles of intrabacterial catalase and superoxide dismutase in the resistance of Escherichia coli to killing by neutrophils. E. coli in which the synthesis of superoxide dismutase and catalase were induced by paraquat 10-fold and 5-fold, respectively, did not resist killing by neutrophils. When bacteria were allowed to recover from the toxicity of paraquat for 1 h on ice and for 30 min at 37 degrees C, they still failed to resist killing by neutrophils. Induction of the synthesis of catalase 9-fold by growth in the presence of phenazine methosulfate did not render E. coli resistant to killing by either neutrophils or by H2O2 itself. The lack of protection by intrabacterial catalase from killing by neutrophils could not be attributed to an impermeable bacterial membrane; the evolution of O2 from H2O2 was no less rapid in suspensions of E. coli than in lysates. The failure of intrabacterial catalase or superoxide dismutase to protect bacteria from killing by neutrophils might indicate either that the flux of O-2 and H2O2 in the phagosome is too great for the intrabacterial enzymes to alter or that the site of injury is at the bacterial surface.

Catalase↗

Predicting coliform concentrations in upland impoundments: design and calibration of a multivariate model.

This paper reports on the calibration and use of a multiple regression model designed to predict concentrations of Escherichia coli and total coliforms in two upland British impoundments. The multivariate approach has improved predictive capability over previous univariate linear models because it includes predictor variables for the timing and magnitude of hydrological input to the reservoirs and physiochemical parameters of water quality. The significance of these results for catchment management research is considered.

Enterobacteriaceae↗

Intraosseous lipoma.

Intraosseous lipoma is the rarest benign primary tumor of bone. The incidence is less than one per 1,000 bone tumors. Because of its rarity and non-specific clinicopathologic findings, large biopsy specimens are needed for an accurate diagnosis. Once diagnosis has been established, a conservative treatment protocol is mandatory. The prognosis is generally excellent, and recurrences have not been reported.

Aged↗

Inhibition by anticoagulant drugs of the progressive hypertension and uremia associated with renal infarction in rats.

We confirmed our previously reported findings that subcutaneous administration of heparin (200 U q 12 hr) in rats with experimental partial renal infarction prevents the development of progressive renal failure and hypertension, as well as the glomerular abnormalities which occur in the remaining viable renal tissue. In the present study, heparin, in the dosage used to prevent progressive renal failure, caused a marked and sustained prolongation of the activated partial thromboplastin time and prothrombin time, as well as a transient prolongation of the bleeding time. Administration of coumadin at doses which caused a significant prolongation of the prothrombin time and bleeding time also inhibited the development of progressive hypertension and uremia in rats with experimental partial renal infarction. These findings indicate that inhibition of blood coagulation effectively protects rats with experimentally decreased renal mass from the development of progressive renal failure and hypertension and support the concept that the glomerular thrombosis plays an important role in the pathogenesis of these complications.

Animals↗

Generation of fecal and total coliform surges by stream flow manipulation in the absence of normal hydrometeorological stimuli.

The response of Escherichia coli and total coliform concentration to increases in river discharge was investigated. Artificial hydrographs were generated on eight occasions between 21 October 1979 and 3 March 1981 by releasing water from Thruscross Reservoir in North Yorkshire into Fewston Reservoir. The majority of the releases were made after rainless periods to isolate the effects of stream channel entrainment from those induced by rainfall on the land surface. In the absence of rainfall, bacterial concentrations are shown to increase more than 10-fold in response to stage increases. It is suggested that two stores of bacteria must exist on the catchment, the first being a land store and the second a channel or near-channel store. Movement from the land to the channel store must relate to hill slope hydrological processes, whereas movement between stores in the channel fluvial system may be closely allied to sedimentary processes. Some consideration is given to bacterial levels in relation to European Economic Communities guidelines for contact recreation.

England↗

Dose-related effects of flurazepam on human sleep-walking patterns.

Two consecutive nights of flurazepam at each of 15, 26, and 45 mg were compared to placebo in a Latin-square double-blind crossover design using 24 healthy young-adult males. Flurazepam had significant hypnotic effects on objective and subjective measures of efficacy: shorter sleep latency, longer sleep time, and fewer awakenings. It also induced morning sedation along with decrements in cognitive performance. Flurazepam had dose-related impacts on both human and computer-scored EEG-EOG parameters: less stages 3 + 4 and decreased EEG delta, less stage 1 REM and decreased REM density, more stage 2 and increased EEG spindling. Also, EEG alpha and movement artifact were decreased and EEG beta was increased. Only a few of the EEG-EOG variables and none of the subjective indices had cumulative changes on the two drug nights. Stage shifting was unaffected at the two lower doses on the first night but decreased at all three dose levels on the second night; percent stages 3 + 4 was unaffected on the first night but decreased at all dose levels on the second night. The rate of delta waveform activity was also diminished by a greater amount on the second night. This study conclusively established that flurazepam affects the EEG-EOG architecture of sleep on each of the first two nights of administration.

Adult↗

Dose-related effects of phenobarbitone on human sleep-waking patterns.

1 Twenty-four healthy male subjects had two consecutive drug nights at 2-week intervals using placebo and 80, 140 and 240 mg doses of phenobarbitone in a double-blind cross-over design. 2 Phenobarbitone produced significant dose-related decreases in sleep latency and number of awakenings, along with increased total sleep time. 3 Both subjective and objective measures of sleep indicated the presence of cumulative (first v second night) effects of phenobarbitone, especially decreases in the number of awakenings and in delta waveform activity. 4 Measures of REM sleep were highly sensitive to phenobarbitone. The high dose decreased REM density to 30% of baseline on the first night and to 18% on the second night. 5 EEG alpha activity was decreased, beta activity was increased and sigma spindle activity was unaffected by phenobarbitone during sleep. 6 Subjects experienced some impairment of cognitive performance along with residual sedation the following morning.

Adult↗