Biomedical subjects
S Simons
Publications and source records attributed to S Simons.
Abdominal coarctation in a hypertensive female collegiate basketball player.
The purpose of the preparticipation examination is to identify health conditions that might adversely affect an athlete while participating in sport. Hypertension is the most common. This case report details a female basketball player found to be hypertensive, and complaining of fatigue, at her preparticipation physical examination. Presentation, diagnostics, treatment, and final outcome of coarctation involving the abdominal aorta are summarised.
Investigation of multidrug-resistant Salmonella serotype typhimurium DT104 infections linked to raw-milk cheese in Washington State.
CONTEXT: Multidrug-resistant Salmonella Typhimurium DT104 has recently emerged as a cause of human and animal illness in Europe and North America. In early 1997, health officials in Yakima County, Washington, noted a 5-fold increase in salmonellosis among the county's Hispanic population. OBJECTIVES: To characterize bacterial strains and identify risk factors for infection with Salmonella Typhimurium in Yakima County. DESIGN: Laboratory, case-control, and environmental investigations. SETTING AND PARTICIPANTS: Patients with culture-confirmed Salmonella Typhimurium infection living in Yakima County and age- and neighborhood-matched control subjects. MAIN OUTCOME MEASURES: Food vehicle implication based on case-control study and outbreak control. RESULTS: Between January 1 and May 5, 1997, 54 culture-confirmed cases of Salmonella Typhimurium were reported. The median age of patients was 4 years and 91% were Hispanic. Patients reported diarrhea (100%), abdominal cramps (93%), fever (93%), bloody stools (72%), and vomiting (53%); 5 patients (9%) were hospitalized. Twenty-two patients and 61 control subjects were enrolled in the case-control study. Seventeen case patients (77%) reported eating unpasteurized Mexican-style soft cheese in the 7 days before onset of illness compared with 17 control subjects (28%) (matched odds ratio, 32.3; 95% confidence interval, 3.0-874.6). All case-patient isolates were phage definitive type 104 (DT104) (n = 10) or DT104b (n = 12), and 20 (91%) were resistant to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline. The cheese produced and eaten by 2 unrelated patients was made with raw milk traced to the same local farm. Milk samples from nearby dairies yielded Salmonella Typhimurium DT104. The incidence of Salmonella Typhimurium infections in Yakima County returned to pre-1992 levels following interventions based on these findings. CONCLUSIONS: Multidrug-resistant Salmonella Typhimurium DT104 emerged as a cause of salmonellosis in Yakima County, and Mexican-style soft cheese made with unpasteurized milk is an important vehicle for Salmonella Typhimurium DT104 transmission. We postulate that recent increases in human salmonellosis reflect the emergence of Salmonella Typhimurium DT104 among dairy cows in the region. Continued efforts are needed to discourage consumption of raw milk products, promote healthier alternatives, and study the ecology of multidrug-resistant Salmonella Typhimurium.
The Nuclear Receptor Resource: a growing family.
Last year, the original Glucocorticoid Receptor Resource was expanded into a comprehensive project: the Nuclear Receptor Resource (NRR, http:// nrr.georgetown.edu/nrr/nrr.html ). The NRR has since been offering comprehensive information on nuclear receptor structure and function, as well as general facts of interest to the scientific community on meetings, funding and employment opportunities. The project now includes individual resources as part of a network which integrates information on glucocorticoid, androgen, mineralocorticoid, thyroid hormone, Vitamin D and peroxisome-proliferator activated receptors. Many investigators have joined the NRR network by filling the Who is who? form available in the NRR home page. This has facilitated communication among scientists in the field and dissemination of data nor otherwise published. Because several investigators have contacted NRR authors over the past few months asking for advice and materials for educational purposes, we have recently decided to include in our project an educational resource on nuclear receptors termed the 'Graphics Library'. The input and suggestions of NRR users do shape the future direction of the project, so we encourage user to give us feedback.
CT-simulator based brachytherapy planner: seed localization and incorporation of biological considerations.
Radiation dose prescription, interpretation, and planning can be problematic for brachytherapy due to high spatial heterogeneity, varying and various dose rates, absence of superimposed calculated isodose distributions onto affected tissues, and lack of dose volume histograms. A new treatment planner has been developed to reduce these limitations in brachytherapy planning. The PC-based planning system uses a CT-simulator to sequentially scan the patient to generate orthogonal images (to localize seed positions) and subsequently axially scan the patient. This sequential scanning procedure avoids using multiple independent patient scans, templates, external frames, or fiducial markers to register the reconstructed seed positions with patient contours. Dose is computed after assigning activity to (low dose rate) Ir192, linear Cs137, or I125 seeds or dwell times (high dose rate) to the Ir192 source. The planar isodose distribution is superimposed onto axial, coronal, or sagittal views of the tissues following image reconstruction. The treatment plan computes (1) direct and cumulative volume dose histograms for individual tissues, (2) the average, standard deviation, and coefficient of skewness of the dose distribution within individual tissues, (3) an average (over all tissue pixels) survival probability (S) and average survival dose DASD for a given radiation treatment, (4) normal tissue complication probability (NTCP) delivered to a given tissue. All four computed quantities account for dose heterogeneity. These estimates of the biological response to radiation from laboratory-based studies may help guide the evaluation of the prescribed low- or high-dose rate therapy in retrospective and prospective clinical studies at a number of treatment sites.
Memory effects in the action of ozone on conifers.
Conifers are known to possess relative ozone tolerance in short-term experiments. A scenario for ozone damage of conifers is now derived from the first exposure experiments in which both the initial biochemical response phase and delayed visible symptom development were studied. A number of early biochemical ozone responses could be detected in Norway spruce (Picea abies [L.] Karst.) and Scots pine (Pinus sylvestris L.). The stress metabolite catechin persisted over several months. In the year following ozone treatment of spruce, decreases in pigment content and photosynthetic capacity, as well as development of visible symptoms (chlorosis, banding), were determined in the needle age classes previously exposed to an accumulated hourly ozone dose above 40 ppb (AOT40) of >/=60-80 ppm small middle doth. The visible symptoms developed during spring emergence of the new flush. In the case of Scots pine, an ozone dose (AOT40) of >/=30 ppm small middle doth caused the premature shedding of needles 9 months after treatment. The delayed symptoms of both spruce and pine occurred during known phases of endogenous stress. The symptoms appeared to reflect an ozone "memory" imprinted by the induced early stress reactions. Ambient AOT40 ozone doses in Central Europe are in the range 4 and 50 ppm small middle doth per growing season. Ozone is proposed to potentially damage conifers through memory effects ("abiotic" pathway) or through predisposition for pathogen attack ("biotic" pathway).
Two-dimensional film dosimetry application in heterogeneous materials exposed to megavoltage photon beams.
Measurement of dose within tissues and tissue interfaces having sharp density discontinuities and heterogeneities (such as in the lung, esophagus, and rectum) is essential for treatment plan verification and accurate prediction of the prescribed dose. This study examines the feasibility and utility of simplifying standard film dosimetry to measure dose distributions deposited by megavoltage beams in tissue substitutes (such as cork for lung) and anthropomorphic phantoms which closely resemble human tissues having large density heterogeneities and having sharp tissue interfaces. In addition, film dosimetry determined the dose distribution involving superposition of multiple radiation fields and helped evaluate the accuracy of a commercial treatment planning program which incorporates tissue heterogeneity effects through the "effective path length" algorithm. This study shows that these treatment planning programs and simple calculations overestimate the dose delivered within the lower density material in heterogeneous regions.
The laryngeal mask airway for awake diagnostic bronchoscopy. A retrospective study of 200 consecutive patients.
The laryngeal mask airway (LMA) provides a view of the larynx and moving vocal cords without loss of airway control and can be used in flexible fibreoptic bronchoscopy for both anaesthetized and awake patients. In this retrospective review of 200 consecutive patients over a 30 month period, bronchoscopy was successful via the LMA in all but one patient using a technique of topical anaesthesia and sedation. The LMA directs the fibrescope to the glottis, allows respiratory function to be monitored and oxygen to be given. Complication rates were similar to those reported for transnasal awake bronchoscopy. Insertion of the LMA in the awake fasted patient is safe and easily achieved.
The laryngeal mask airway and endoscopic guided percutaneous tracheostomy.
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Monitoring practice: simplifying and strengthening the process.
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Immunological analyses of the chemotactic receptor of Dictyosteleum discoideum. Identification of cDNA clones.
The cell surface cAMP receptor was excised from preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and used to generate a polyclonal antiserum. The antiserum immunoprecipitates the two molecular weight forms of the cAMP receptor. Both forms are phosphorylated. Western blot analyses show that the antiserum is highly specific and recognizes only the two molecular weight forms of the cAMP receptor. Immunological studies indicate that both forms of the receptor are phosphorylated. Vegetative amoebae possess low levels of the cAMP receptor. Levels of the antigen increase in differentiated cells which express high cell surface cAMP binding activity. The antiserum was also used to isolate 6 lambda gt11 cDNA clones. One of those clones contains a 1.1-kilobase pair cDNA fragment which encodes for a protein of approximately 30,000-35,000 daltons. The antibody which binds to the fusion protein also recognizes the two molecular weight forms of the receptor.
[Breast carcinoma in women over 70].
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cAMP induces a rapid and reversible modification of the chemotactic receptor in Dictyostelium discoideum.
Stimulation, within 1 min after cAMP stimulation, of aggregation-competent Dictyostelium discoideum amebae was found to cause a rapid (within 1 min) modification of the cell's surface cAMP receptor. The modified receptor migrated on SDS PAGE as a 47,000-mol-wt protein, as opposed to a 45,000-mol-wt protein labeled on unstimulated cells. The length of time this modified receptor could be detected depended upon the strength of the cAMP stimulus: 3-4 min after treatment with 10(-7) M cAMP, cells no longer possessed the 47,000-mol-wt form of the cAMP receptor. Instead, the 45,000-mol-wt form was present. Stimulation of cells with 10(-5) M cAMP, however, resulted in the persistent (over 15 min) expression of the modified receptor. The time course, concentration dependence, and specificity of stimulus for this cAMP-induced shift in the cAMP receptor were found to parallel the cAMP-stimulated phosphorylation of a 47,000-mol-wt protein. In addition, both phenomena were shown to occur in the absence of endogenous cAMP synthesis. The possibility that the cAMP receptor is phosphorylated in response to cAMP stimulation, and the role of this event in cell desensitization, are discussed.
Lipid and myelin abnormalities of brain in the crinkled mouse.
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Intranuclear localization of mercury in vivo.
Purified nuclei isolated from mice challenged with nonlethal levels of mercury chloride (10-(3)M) in drinking water for 4 to 7 weeks (experimental) and from animals given deionized water (control) were fractionated and the subsequent fractions were analyzed for mercury by flameless atomic absorption. Control (active) euchromatin contained 1.75 +/- 0.53 micrograms of mercury per milligram of DNA. There was a 12- to 15-fold enrichment of mercury in the euchromatin fraction of challenged animals. Mercury was not detected in control (inactive) heterochromatin, and only trace levels (parts per billion) appeared in experimental heterochromatin. It seems likely that mercury can be incorporated into chromatin as a metal-protein complex, but the possibility of protein-mercury-DNA or mercury-DNA complexes within euchromatin cannot be excluded.
Psychiatric services in penal institutions. II. A detailed survey of patients hospitalised on a given day.
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