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Biomedical subjects

G Peterson

Publications and source records attributed to G Peterson.

At least 73 records · Page 4Linked to original sources
PubMed1993

The C-terminal tripeptide of glycosomal phosphoglycerate kinase is both necessary and sufficient for import into the glycosomes of Trypanosoma brucei.

Glycosomal phosphoglycerate kinase (gPGK) of Trypanosoma brucei differs from the cytoplasmic isozyme (cPGK) in its higher isoelectric point characterized by clusters of positive charges along the polypeptide chain, and a 20 amino acid C-terminal extension ending in serine-serine-leucine (SSL). While a C-terminal SSL tripeptide is apparently not capable of directing luciferase to the peroxisomes in mammalian cells [J. Cell Biol. 108 (1989), 1657-1664], we show here that it is sufficient for the import of luciferase as well as an unrelated protein, beta-glucuronidase, into the glycosomes of T. brucei, as determined by immunoelectron microscopy. The analysis of luciferase-gPGK fusion proteins indicates that the only targeting signal for import of gPGK into the glycosome resides in this C-terminal SSL sequence.

Amino Acid Sequence↗
PubMed1993

Genistein and biochanin A inhibit the growth of human prostate cancer cells but not epidermal growth factor receptor tyrosine autophosphorylation.

The effect of the isoflavones, genistein, daidzein, and biochanin A on the growth of the LNCaP and DU-145 human prostate cancer cell lines has been examined. Genistein and biochanin A, but not daidzein, inhibit both serum and EGF-stimulated growth of LNCaP and DU-145 cells (IC50 values from 8.0 to 27 micrograms/ml for serum and 4.3 to 15 micrograms/ml for EGF), but have no significant effect of the EGF receptor tyrosine autophosphorylation. In contrast, tyrphostin 25, a specific EGF receptor tyrosine kinase inhibitor, inhibits EGF-stimulated growth and EGF receptor tyrosine autophosphorylation in these whole cells, but does not inhibit serum-stimulated growth. These data suggest that the mechanism of action of genistein and biochanin A does not depend on inhibition of EGF receptor tyrosine autophosphorylation, but on a more distal event in the EGF receptor-mediated signal transduction cascade.

Anticarcinogenic Agents↗
PubMed1991

Genistein inhibition of the growth of human breast cancer cells: independence from estrogen receptors and the multi-drug resistance gene.

The effect of isoflavones on the growth of the human breast carcinoma cell lines, MDA-468 (estrogen receptor negative), and MCF-7 and MCF-7-D-40 (estrogen receptor positive), has been examined. Genistein is a potent inhibitor of the growth of each cell line (IC50 values from 6.5 to 12.0 micrograms/ml), whereas biochanin A and daidzein are weaker growth inhibitors (IC50 values from 20 to 34 micrograms/ml). The isoflavone beta-glucosides, genistin and daidzin, have little effect on growth (IC50 values greater than 100 micrograms/ml). The presence of the estrogen receptor is not required for the isoflavones to inhibit tumor cell growth (MDA-468 vs MCF-7 cells). In addition, the effects of genistein and biochanin A are not attenuated by overexpression of the multi-drug resistance gene product (MCF-7-D40 vs MCF-7 cells).

Antineoplastic Agents↗
PubMed1991

The electron impact, chemical ionization and fast atom bombardment positive ion mass spectra of 1,2-bis(sulfonyl)methylhydrazines.

A series of bis(sulfonyl)-1-methylhydrazines were analyzed by positive ion electron impact (EI), chemical ionization (CI) and fast atom bombardment (FAB) mass spectrometry. Since these compounds showed activity against the L1210 leukemia, an understanding of their mass spectral behavior is important should the structural characterization of metabolites be required. FAB proved to be the most useful technique, generally providing abundant protonated molecule ion peaks, in contrast to the weak peaks observed with CI (ammonia or isobutane) and the total absence of molecular ion peaks in the EI mass spectra. In addition, utilizing FAB eliminated the problem of thermal decomposition, which was very difficult to control under EI and CI experimental conditions. Fragments observed in FAB and CI mass spectra were consistent with protonation at the methyl-bearing nitrogen. One can locate the R1 and R2 moieties relative to the methyl-bearing nitrogen in FAB and CI by assigning that nitrogen as the site of protonation, with subsequent elimination of R2SO2H.

Antineoplastic Agents↗
PubMed1991

Psychological aspects of orthognathic surgery: how people respond to facial change.

This study was undertaken to explore the motivations and problems shared by adult orthognathic surgical patients over the age of 25. Objective findings included demographic information and reasons for seeking surgery. The majority of 65 respondents cited functional problems as their primary reason for seeking treatment. Eighty-nine percent were pleased with esthetic changes, and 83% responded that the functional problem had been corrected. For most, the greatest discomfort related to the surgery was the postoperative intensive care unit. Two of the most common side effects of the surgery were the loss of sensation in the lips and chin area and a short period of depression. Women had depression more often than men but were more enthusiastic about the final results of the procedure. Two major areas of interest to surgeons emerged from the research. First, although women have functional problems, the majority seem to have a desire for cosmetic improvement. Having a functional problem seemed to provide the psychological permission necessary to spend the time and money for a cosmetic change. The second point focused on the need for good communication between surgeon and patient. The patients who were more positive toward the procedure and more satisfied with the results were those who were better informed and who thought they had a good system of communication with the orthodontist, surgeon, and their respective staffs.

Adult↗
PubMed1991

Community-based approach to weight loss: the Pawtucket "weigh-in".

The Pawtucket Heart Health Program (PHHP), in its attempt to treat obesity in the community, has delivered many traditional group and self-help weight loss programs. However, in order to reach a sufficient number of people to produce a public health impact in Pawtucket, PHHP devised a monthly city-wide "weigh-in." This program, designed to be delivered by volunteers, allowed individuals to set a weight loss goal and pledge a monetary incentive toward this goal. Self-help materials and the opportunity to join weight loss groups were provided. In the pilot study, 129 (61%) of 213 enrollees completed the 10-week program with a mean weight loss of 8.2 lb (p less than .001). A large decrease in total serum cholesterol was also observed. Nonpersonnel costs, including the total costs of the cholesterol measurement, were $1.30 per pound lost. Moreover, success is also evident by continued availability of the program and the increasing number of new participants "referred" to the weigh-in by members.

Adult↗
PubMed1991

Oxytocin selectively increases holding and licking of neonates in preweanling but not postweanling juvenile rats.

Preweanling rats exhibit components of maternal behavior (MB) after brief periods of contact with neonates; the latency of onset of MB rises considerably after weaning. Oxytocin (OXT) stimulates MB in adult rats. The effects of intracisternal (IC) administration of OXT (2 micrograms) on pup-directed and other behaviors in preweanling and postweanling juvenile rats were tested. Compared with saline and no treatment, OXT significantly increased active holding of pups in preweanling but not postweanling juvenile rats. No other components of adultlike MB were stimulated by OXT. OXT also decreased inactive touching of pups and robustly increased selfgrooming in juveniles at all ages tested. It is concluded that OXT facilitation of active pup-holding and licking in preweanling rats may be an extension of OXT-induced self-grooming to pups and may also be related to OXT activation of MB in adult rats.

Age Factors↗
PubMed1991

Transformation of Zea mays L. Using Agrobacterium tumefaciens and the Shoot Apex.

Agrobacterium tumefaciens is established as a vector for gene transfer in many dicotyledonous plants but is not accepted as a vector in monocotyledonous plants, especially in the important Gramineae. The use of Agrobacterium to transfer genes into monocot species could simplify the transformation and improvement of important crop plants. In this report we describe the use of Agrobacterium to transfer a gene into corn, the regeneration of plants, and detection of the transferred genes in the F(1) progeny. Shoot apices of Zea mays L. variety Funk's G90 were cocultivated with A. tumefaciens EHA 1, which harbored the plasmid pGUS3 containing genes for kanamycin resistance (NPT II) and beta-glucuronidase (GUS). Plants developed from these explants within 4 to 6 weeks. Fluorometric GUS assays of leaves and immature seeds from the plants exhibited low GUS activity. Both NOS and GUS gene fragments were amplified by polymerase chain reaction in the DNA isolated from the F(1) generations of one of the original transformed plants. Southern analysis showed both GUS and NPT probes hybridized to DNA in several of the F(1) progeny, demonstrating the incorporation of GUS and NPT II genes into high molecular weight DNA. These data establish successful gene transfer and sexual inheritance of the genes.

Journal Article↗
PubMed1991

Kinetics and quality assurance: prescription therapy through kinetic modeling.

With recent startling statistics showing an increase in mortality risk of dialysis patients in the United States compared to other countries, managers and practitioners have been motivated to carefully examine not only the dialysis prescription, but what is actually delivered to the patient. In October 1990, prior to ANNA's Clinical Concerns in Nephrology meetings in Cincinatti and San Antonio, attendants were invited to participate in an education session examining the monitoring and evaluation of prescription therapy for peritoneal and hemodialysis. The title of the session was "The Nurse's Role in Prescription Therapy--What Does it Really Mean?" The sponsor was Fresenius USA, Inc. This educational offering gave the nephrology nurse the opportunity to learn how to manage the delivery of care based on the theory of kinetic modeling for peritoneal and hemodialysis therapy. Quality assurance indicators, data collection tools, and the latest technology were described for the monitoring and evaluation of the adequacy of therapy. The following article is adopted from the original transcripts of the five-member panel of experts who participated in the session. We appreciate the willingness of the speakers to share this timely and important material with the ANNA Journal readers.

Data Collection↗
PubMed1990

Nontraumatic prehospital cardiac arrest ages 1 to 39 years.

Clinical and autopsy records were retrospectively reviewed for 105 patients between the ages of 1 and 39 years who came in to the emergency department with nontraumatic cardiac arrest. There were 65 male (62%) and 40 female patients (38%). Forty-eight percent of the patients were resuscitated. Long-term survival rate was 23%. The most common presenting rhythm was ventricular fibrillation (45%). Cardiac diseases constituted the most common cause of arrest (38%). Atherosclerotic coronary artery disease represented 50% of all cardiac causes. The second most common etiology was overdose or toxic exposure (21%). Witnessed arrest and an etiology of primary cardiac dysrhythmia for arrest were statistically significant factors related to favorable outcome. Asystole as the initial cardiac rhythm was a negative prognostic indicator. Age, sex, race, bystander cardiopulmonary resuscitation, and paramedic response time were not significant prognostic factors for long-term survival.

Adolescent↗
PubMed1990

Perioperative and long-term prognostic value of intravenous dipyridamole thallium scintigraphy in patients with peripheral vascular disease.

The prognostic value of long-term risk stratification of patients with peripheral vascular disease who undergo intravenous dipyridamole thallium scintigraphy has not been well studied. We screened 131 patients with peripheral vascular disease who underwent intravenous dipyridamole thallium testing to determine cardiac event rates over an average follow-up of 18 +/- 10 months. Of the 131 patients, 111 subsequently had peripheral vascular surgery. The patients with abnormal thallium scans after dipyridamole had a significantly higher risk of death or myocardial infarction, both in the perioperative phase (7% versus 0%; p less than 0.001) and at late follow-up (17% versus 6%; p less than 0.01). The risk of a cardiac event was two-fold greater when a reversible as compared to a fixed thallium defect was present. Multivariate analysis selected the number of thallium segments with perfusion defects, prior history of angina pectoris, and chest pain during dipyridamole testing as perioperative predictors of a cardiac event. A reversible thallium defect was the only predictor of death or nonfatal myocardial infarction during late follow-up. Thus intravenous dipyridamole thallium scintigraphy is a useful noninvasive test for risk stratification of patients before peripheral vascular surgery and provides prognostic information as to the risk of a cardiac event in the 2-year period after the test. A reversible thallium defect is associated with a significant increased risk and would indicate that coronary angiography should be considered and preoperative coronary revascularization.

Aged↗