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Biomedical subjects

E J Larson

Publications and source records attributed to E J Larson.

At least 19 recordsLinked to original sources
PubMed2000

Rapid DNA fingerprinting of pathogens by flow cytometry.

BACKGROUND: A new method for rapid discrimination among bacterial strains based on DNA fragment sizing by flow cytometry is presented. This revolutionary approach combines the reproducibility and reliability of restriction fragment length polymorphism (RFLP) analysis with the speed and sensitivity of flow cytometry. METHODS: Bacterial genomic DNA was isolated and digested with a rare-cutting restriction endonuclease. The resulting fragments were stained stoichiometrically with PicoGreen dye and introduced into an ultrasensitive flow cytometer. A histogram of burst sizes from the restriction fragments (linearly related to fragment length in base pairs) resulted in a DNA fingerprint that was used to distinguish among different bacterial strains. RESULTS: Five different strains of gram-negative Escherichia coli and six different strains of gram-positive Staphylococcus aureus were distinguished by analyzing their restriction fragments with DNA fragment sizing by flow cytometry. Fragment distribution analyses of extracted DNA were approximately 100 times faster and approximately 200,000 times more sensitive than pulsed-field gel electrophoresis (PFGE). When sample preparation time is included, the total DNA fragment analysis time was approximately 8 h by flow cytometry and approximately 24 h by PFGE. CONCLUSIONS: DNA fragment sizing by flow cytometry is a fast and reliable technique that can be applied to the discrimination among species and strains of human pathogens. Unlike some polymerase chain reaction (PCR)-based methods, sequence information about the bacterial strains is not required, allowing the detection of unknown, newly emerged, or unanticipated strains.

DNA Fingerprinting↗
PubMed1999

Bacterial fingerprinting by flow cytometry: bacterial species discrimination.

BACKGROUND: A flow cytometric measurement (FCM) technique has been developed to size DNA fragments. Individual fragments of a restriction digest of genomic DNA, stained with an intercalating dye, are passed through an ultrasensitive cytometer. The measured fluorescence intensity from each fragment is proportional to the fragment length. METHODS: The isolation of bacterial genomic DNA and digestion by restriction enzymes were performed inside an agarose plug. Rare cutting enzymes were employed to produce a manageable number of DNA fragments. Electroelution was used to move the DNA fragments from the agarose plug into a solution containing polyamines to protect the DNA from shear-induced breakage. The DNA was stained with the bisintercalating dye thiazole orange homodimer and introduced into our ultrasensitive flow cytometer. A histogram of the fluorescence intensities (fingerprint) was constructed. RESULTS: Gram-positive Bacillus globigii and gram-negative bacteria Escherichia coli and Erwinia herbicola were distinguished by the fingerprint pattern of restriction fragments of their genomic DNA. DNA sizes determined by FCM are in good agreement with pulsed-field gel electrophoresis (PFGE) analysis. Flow cytometry requires only picogram quantities of purified DNA and takes less than 10 min for data collection and analysis. When the total sample preparation time is included, the analysis times for PFGE and FCM are similar ( approximately 3 days). CONCLUSIONS: FCM is an attractive technique for the identification of bacterial species. It is more sensitive and potentially much faster than PFGE.

Bacteria↗
PubMed1994

Implementation and impact of the Patient Self-Determination Act.

The Patient Self-Determination Act became effective in December 1991 and mandates that patients be given information about legal rights regarding living wills and durable powers of attorney for health care. We investigated the impact this law has had on hospitals, medical personnel, and patients. We conducted a survey of all hospitals in the state of Georgia, collecting data regarding implementation and knowledge of the law, as well as effects of the law and beliefs about it. The data indicated that hospitals relied primarily on the Georgia Hospital Association for implementation policy, that "minimalist" implementation of the law occurs in most hospitals, and that the biggest perceived problem with the law was the inappropriateness of presenting this information at hospital admission and problems patients had in comprehending the materials presented. Despite these concerns, most respondents did not want the law repealed.

Attitude of Health Personnel↗
PubMed1990

Beckwith-Wiedemann syndrome: development of nephroblastoma during the surveillance period.

Two children, with Beckwith-Wiedemann syndrome and hemihypertrophy who were followed by ultrasonography, developed a large nephroblastoma in the interval between two abdominal ultrasound examinations. The customarily suggested bi-annual examinations are not frequent enough and may give physicians and parents a false sense of security.

Beckwith-Wiedemann Syndrome↗
PubMed1990

Personhood: current legal views.

Medical developments have given people unprecedented control over the beginning and end of life but have also altered traditional and legal concepts of personhood. Recent court decisions on prefetal life, fetuses, the infirm, and the dying reflect a struggle with the new ambiguity surrounding the definition of "person."

Abortion, Legal↗
PubMed1987

Fetal echocardiography: the prenatal diagnosis of a ventricular septal defect in a 14-week fetus with pulmonary artery hypoplasia.

As the result of auscultation of fetal bradycardia in a class C diabetic, real-time and M-mode echocardiography were performed at 14 weeks of gestation. M-mode evaluation revealed fetal bradycardia (70 beats per minute) with atrial and ventricular systole occurring simultaneously, suggesting a nodal rhythm. Real-time examination demonstrated a ventricular septal defect, pericardial effusion, ventricular wall hypertrophy, and a dilated aortic root. Also present were fetal ascites and situs inversus of the stomach. A repeat ultrasound examination revealed fetal death at 16 weeks of gestation. Autopsy confirmed the above structural abnormalities, and also demonstrated bilobed lungs, pulmonary artery and valve hypoplasia, midline small intestine, and asplenia.

Adult↗
PubMed1987

Pathological features of Kawasaki disease (mucocutaneous lymph node syndrome).

Kawasaki disease (mucocutaneous lymph node syndrome) (MCLS) is an apparently infectious disease, an etiological agent of which has not been established, with peak age incidence at about 1 year, but with progressively fewer cases occurring into the fourth decade. Early clinical features include fever, rash, conjunctival injection, dry reddened lips, oropharyngeal reddening, enlarged cervical nodes, and swelling and redness of hands and feet. Peeling of skin of fingers and toes, arthralgia, and marked thrombocytosis are frequent 1-2 weeks after onset. Myocarditis, cardiac valvulitis, and lymphocytic or mixed interstitial infiltration of pancreas, renal, splenic, and hepatic hilar regions are seen in the early phase, but arteritis, typically of extraparenchymal arteries, is the most important aspect of MCLS, hence the term infantile periarteritis nodosa, formerly applied to fatal cases of MCLS. Thrombosis of coronary artery aneurysms is the most common cause of death (rate about 0.5%). The peak time of death is 3-4 weeks from onset, but death from coronary occlusion has been seen as late as 14 years after the acute phase. Aneurysmal rupture with hemopericardium or retroperitoneal hemorrhage is rare, as are late brachial, iliac, or other arterial aneurysms. Pathological features of MCLS in the early and later stages are described and illustrated, and the epidemiologic, etiologic, forensic, and other aspects of the disease are discussed.

Adolescent↗
PubMed1984

Association of hemolytic anemia and early-onset pulmonary emphysema in three siblings.

Three of four siblings born to nonconsanguineous parents of Italian origin were affected with severe congenital hemolytic anemia of unknown cause, and early-onset pulmonary emphysema. Two of the three affected siblings died of septic shock after splenectomy, at the ages of 7 and 3 1/2 years, respectively. The remaining affected sibling was shown to have cutis laxa and severe pulmonary emphysema at 15 years of age. Assay of serum components indicated that alpha 1-antitrypsin and alpha 2-macroglobulin levels were normal or slightly elevated. However, there was markedly elevated activity of an elastase-like serum enzyme. The relation of the hemolytic anemia to the pulmonary findings in this family is not clear; pedigree analysis suggests a recessively inherited defect.

Adolescent↗
PubMed1982

Acute, subacute and chronic toxicity/Carcinogenicity of lofexidine.

Acute, subacute and chronic toxicity-carcinogenicity studies of 2-[1-(2,6-dichlorphenoxy)-ethyl]-2-imidazoline hydrochloride (lofexidine, Lofetensin and Loxacor) were conducted in rats, dogs, and/or mice. The oral LD50 values for these species were similar. Lofexidine given orally to rats and dogs for up to 12 months produced no significant adverse effects at doses up to 1 mg/kg and only marginal effects at 3 mg/kg; moderate to severe effects were noted at doses of 5-25 mg/kg. When given orally to rats for 24 months at doses of 0.1-1.0 mg/kg, lofexidine failed to elicit any evidence of carcinogenicity. Phentolamine and tolazoline may be useful as antidotes in cases of overdosage.

Animals↗
PubMed1982

Teratologic and reproductive studies of lofexidine.

2-[1-(2,6-Dichlorphenoxy)-ethyl]-2-imidazoline hydrochloride (lofexidine, Lofetensin and Loxacor) elicited no evidence of teratogenicity when administered orally during the period of organogenesis to pregnant rats at doses up to 3.0 mg/kg/day or to pregnant rabbits at doses up to 15.0 mg/kg/day. In reproductive studies there were no effects on conception or pregnancy in male or female rats at dosages up to 1.0 mg/kg/day or male or female rabbits at dosages up to 1.5 mg/kg/day. Dosages of 1.0 mg/kg/day in rats and 6.4 mg/kg/day in rabbits reduced survival and growth rates of neonates and dosages of 3.0 mg/kg/day in rats and 5.0 mg/kg/day or more in rabbits caused reduced fetal weights and increased postimplantation losses. Since neonatal effects occurred only at dosages which produced clinical signs in the dams (1.0 mg/kg/day in rats and 1.5 mg/kg/day in rabbits which correspond to 100 or 150 times, respectively, the therapeutic dose in man) and since fetal effects occurred only at those dosages which caused some maternal deaths, the adverse fetal and neonatal effects produced by lofexidine were attributed to maternal toxicity rather than a direct effect on the fetus or newborn.

Animals↗
PubMed1982

Toxicology of the combination lofexidine/hydrochlorothiazide.

The toxicity and side-effects of the antihypertensive and diuretic combination 2-[1-(2,6-dichlorphenoxy)-ethyl-2-imidazoline-hydrochloride (lofexidine, Lofetensin and Loxacor) hydrochlorothiazide were studied in toxicity and teratogenicity tests and the possibility of interactions was investigated. In terms of lofexidine, there was no evidence of any adverse interactions with hydrochlorothiazide either following a single, oral administration to rats and mice or following short-term and long-term repeated oral dosing of rats and dogs. In the subchronic and chronic toxicity studies it was actually found that the familiar, unwanted sedative effect of lofexidine failed to occur when the combined preparation was given. With repeated oral administration to rats and dogs definite drug-related toxic findings, such as a reduction in serum potassium, mineralization of a few organs and crystal formation in the urine, only occurred at dose levels far above the therapeutic dose. The results of these studies along with historical data on the individual components would suggest a lack of carcinogenic potential for this combination. No teratogenic or embryotoxic effects were noted in rats or rabbits.

Animals↗
PubMed1977

Are infantile periarteritis nodosa with coronary artery involvement and fatal mucocutaneous lymph node syndrome the same? Comparison of 20 patients from North America with patients from Hawaii and Japan.

We reviewed available clinical and pathologic autopsy material from 20 patients with infantile periarteritis nodosa with coronary artery involvement (IPN) from the continental United States, two Hawaiian patients with fatal mucocutaneous lymph node syndrome (MCLS; Kawasaki disease), and three patients with classical periarteritis nodosa (CPN). Comparison of the findings in patients with IPN and in patients with MCLS from Hawaii to material from patients with fatal MCLS from Japan showed no definite clinical reason to distinguish IPN from MCLS; neither gross nor microscopic features of the vascular lesions nor their pattern of distribution appears to warrant separation of IPN from fatal MCLS. CPN differs, both clinically and pathologically, from IPN/MCLS, and may well have a different etiology.

Adult↗