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Biomedical subjects

J L Green

Publications and source records attributed to J L Green.

At least 19 recordsLinked to original sources
PubMed2001

Views of Earth's magnetosphere with the image satellite.

The IMAGE spacecraft uses photon and neutral atom imaging and radio sounding techniques to provide global images of Earth's inner magnetosphere and upper atmosphere. Auroral imaging at ultraviolet wavelengths shows that the proton aurora is displaced equatorward with respect to the electron aurora and that discrete auroral forms at higher latitudes are caused almost completely by electrons. Energetic neutral atom imaging of ions injected into the inner magnetosphere during magnetospheric disturbances shows a strong energy-dependent drift that leads to the formation of the ring current by ions in the several tens of kiloelectron volts energy range. Ultraviolet imaging of the plasmasphere has revealed two unexpected features-a premidnight trough region and a dayside shoulder region-and has confirmed the 30-year-old theory of the formation of a plasma tail extending from the duskside plasmasphere toward the magnetopause.

Journal Article↗
PubMed2001

Sequence diversity and antigenic polymorphism in the Plasmodium yoelii p235 high molecular mass rhoptry proteins and their genes.

A gene family in Plasmodium yoelii YM encodes p235, a group of high molecular mass erythrocyte-binding rhoptry proteins. Sequence analysis of 6 cDNA clones from the 3' end of expressed p235 genes divided them into two groups corresponding to genes on chromosomes 1, and 5 and 6, respectively. Twelve partial p235 protein sequences, derived from cDNA sequences from the region with greatest protein sequence similarity to Plasmodium vivax RBP2, fell into three groups, together with one chimeric sequence. A comparison of these cDNA sequences with genomic DNA sequences from the same region suggested that only a subset of the gene repertoire is expressed. Three genomic DNA clones, derived from the 5' end of p235 genes designated E1, E2, and E5 and located on chromosome 5/6, were also obtained and aligned with sequences from the known E8 and E3 genes. In the region of overlap there was only approximately 27% protein sequence identity, indicating that the sequences in this p235 N-terminal region are more diverse than at the C-terminal end. This sequence variation in the expressed genes did not result in antigenically different rhoptry proteins as detected with a panel of p235-specific mAbs. Only one schizont out of 500 examined with mAb 25.86 appeared to be an antigenic variant, with all of the developing merozoites in this schizont being mAb 25.86 negative. No other antigenic variants were detected with the other antibodies, and therefore it is likely that these antibodies recognise conserved epitopes.

3' Untranslated Regions↗
PubMed2001

A prospective observational study of 5-, 7-, and 10-day antibiotic treatment for acute otitis media.

OBJECTIVE: To compare 5-, 7- and 10-day duration of antibiotic therapy for acute otitis media (AOM) in children. STUDY DESIGN AND SETTING: Prospective nonrandomized 1-year evaluation of 3 treatment durations for AOM in a private pediatric setting. Outcomes assessed at 14 +/- 4 days after start of therapy with clinical response categorized as cure, improvement, or failure. RESULTS: A total of 2172 children were studied; 46.4% were < or =2-years-old. Antibiotics used were amoxicillin (61.9% of patients), trimethoprim/sulfamethoxazole (11.7%), cephalosporins (14.2%), amoxicillin/clavulanate (5.2%), and macrolides/azalides (4.8%). No overall difference in outcome was observed comparing the 5-day (n = 707), 7-day (n = 423), or 10-day (n = 1042) treatments, including children < or =2-years-old. However, in the subset who had an episode of AOM in the preceding month, outcome differed; 5-day treatment was followed by more frequent failure than 10-day treatment (P < 0.001). In logistic regression analysis, variables identified as contributing to a cure were: >2-years-old (P < 0.0001), no AOM in the preceding month (P = 0.07), or preceding 12 months (P = 0.03). CONCLUSIONS: Our study supports the transition from 10 to 5 days for standard AOM antibiotic treatment duration in most patients. A 10-day regimen may be superior in children who have experienced an episode of AOM within the preceding month, a known risk factor for resistant bacterial infection in the otitis-prone patient.

Acute Disease↗
PubMed2000

Enhanced pneumocystis carinii activity of new primaquine analogues.

New analogues of the venerable antimalarial drug primaquine have been synthesized and bioassayed in vivo against Pneumocystis carinii, a life-threatening infection common among immunosuppressed patients. Two of these new compounds are significantly more active than primaquine itself, and provide new information for future drug design and development in this area.

Animals↗
PubMed2000

Epidemiology of lung cancer with special reference to genetics, bioassays, women, and developing countries.

The twentieth century may be looked back upon as the century of lung cancer. At the beginning of the century lung cancer was quite rare, but this century the rates have increased approximately 10-fold and it is the second most common type of cancer and has become the leading cause of death due to cancer in the United States. The rate of lung cancer among U.S. women continues to rise, in contrast rates in U.S. men have been declining since about 1990. Cigarette smoking accounts for 85-90% of lung cancer deaths in the United States. However, only 10-15% of smokers eventually develop lung cancer. In the past 25 years, since the U.S. Surgeon General's ground breaking report in 1964, overall smoking rates have been declining, but smoking still remains a significant behavior. More troubling, the rates of smoking continue to increase in many parts of the world. Advances in molecular biology and early diagnosis have increased the understanding of lung cancer etiology and may be effective in uncovering more efficient detection and treatment regimens. These advances will hopefully make lung cancer as uncommon at the end of the twenty-first century, as it was at the beginning of the twentieth century.

Journal Article↗
PubMed2000

Effectiveness of a cardiovascular health promotion education intervention on the attitudes of urban African American school-age children.

African American children are at risk for high rates of morbidity and mortality associated with cardiovascular (CV) disease as they become adults, yet little is known about the effectiveness of CV risk-reduction interventions in African American children. This study explored the effectiveness of a concentrated CV health promotion educational program on health-related attitudes of 76 African American children enrolled in a mid-southern school system. The Children's Cardiovascular Health Promotion Attitude Scale was used to examine differences in attitude prior to and 2 weeks following a focused health education intervention. Results demonstrate that children have preconceived attitudes regarding practice of health behaviors and that these attitudes are modifiable with age and developmental level specific educational interventions. Findings indicate the need for health care providers to assume more active roles in reducing the risk of future CV disease and death in African Americans through health promotion education of individuals who influence the development of children's attitudes.

Black or African American↗
PubMed2000

Corticotropin-releasing hormone type I receptor messenger ribonucleic acid and protein levels in the ovine fetal pituitary: ontogeny and effect of chronic cortisol administration.

In sheep, the ACTH secretory response to CRH in vivo or in vitro changes as a function of development, with peak responses occurring several weeks before term (145 days of gestation). CRH-stimulated ACTH secretion is mediated via the G protein-coupled CRH type I (CRH R1) receptor. We used a quantitative ribonuclease protection assay and Western immunoblotting to determine messenger RNA (mRNA) and protein levels of the CRH R1 receptor in immature and mature fetuses and adults. In addition, we precociously elevated fetal plasma cortisol levels to determine whether the fetal CRH R1 receptor is sensitive to increases in plasma cortisol. CRH R1 receptor mRNA levels decreased markedly throughout gestation and into the transition to adult life (immature fetus, 1.24+/-0.17; mature fetus, 0.75+/-0.13; adult, 0.18+/-0.093 pg/microg total anterior pituitary RNA). Also, continuous cortisol infusion in immature fetuses significantly decreased CRH R1 mRNA levels by 41%. Similar decreases were noted in protein levels. Thus, the decreased ACTH response to CRH stimulation during late gestation may be related to decreased CRH R1 receptor expression. In addition, plasma cortisol levels may influence corticotroph responsiveness to CRH by decreasing CRH R1 receptor expression.

Adrenocorticotropic Hormone↗
PubMed2000

Outcomes after judicious antibiotic use for respiratory tract infections seen in a private pediatric practice.

BACKGROUND: Most respiratory tract infections (RTIs) in children have a viral cause, they resolve on their own, and antibiotics need not be prescribed. OBJECTIVE: We sought to provide evidence that judicious antibiotic use can be accomplished in private pediatric practice without observing an increase in return office visits or in the rate of bacterial infections that may follow. STUDY DESIGN: This was a prospective 12-month study from July 1, 1996 through June 30, 1997. On the same 1 day each week, a representative convenience sample of acute respiratory tract illness patients was enrolled, and laboratory studies performed as appropriate, including viral cultures on all. Children were then followed for 30 days to ascertain the outcomes of not prescribing antibiotics except when specific bacterial infections were present at the initial visit. RESULTS: Three hundred eighty-three children were enrolled; 293 (77%) did not receive antibiotics at the enrollment visit. Ninety children (23%) received antibiotics based on a diagnosis of acute otitis media (n = 53), acute streptococcal tonsillopharyngitis (n = 18), or other presumed or documented bacterial infections (n = 19). An unscheduled return visit related to the initial visit occurred for 86 (29%) of the 293 children not receiving antibiotics initially and in 40 (44%) of 90 children receiving antibiotics initially. Eighty-seven children (23%) had positive viral culture results. The most frequently isolated viruses were adenovirus, enterovirus, parainfluenzae virus, and influenza virus. CONCLUSION: Children with RTIs without a concomitant presumed or proven bacterial infection do not require antibiotics. In this busy office practice, >75% of the children presenting with an RTI did not have a presumed or proven bacterial infection. These children did not have a higher rate of return office visits or an increase in bacterial infections. This reinforces the judicious use of antibiotics in managing children with RTIs.outcomes, antibiotic, respiratory infections.

Agglutination Tests↗
PubMed1999

MiAMP1, a novel protein from Macadamia integrifolia adopts a Greek key beta-barrel fold unique amongst plant antimicrobial proteins.

MiAMP1 is a recently discovered 76 amino acid residue, highly basic protein from the nut kernel of Macadamia integrifolia which possesses no sequence homology to any known protein and inhibits the growth of several microbial plant pathogens in vitro while having no effect on mammalian or plant cells. It is considered to be a potentially useful tool for the genetic engineering of disease resistance in transgenic crop plants and for the design of new fungicides. The three-dimensional structure of MiAMP1 was determined through homonuclear and heteronuclear ((15)N) 2D NMR spectroscopy and subsequent simulated annealing calculations with the ultimate aim of understanding the structure-activity relationships of the protein. MiAMP1 is made up of eight beta-strands which are arranged in two Greek key motifs. These Greek key motifs associate to form a Greek key beta-barrel. This structure is unique amongst plant antimicrobial proteins and forms a new class which we term the beta-barrelins. Interestingly, the structure of MiAMP1 bears remarkable similarity to a yeast killer toxin from Williopsis mrakii. This toxin acts by inhibiting beta-glucan synthesis and thereby cell wall construction in sensitive strains of yeast. The structural similarity of MiAMP1 and WmKT, which originate from plant and fungal phyla respectively, may reflect a similar mode of action.

Amino Acid Motifs↗
PubMed1999

Incidence of streptococcal carriers in private pediatric practice.

OBJECTIVE: To determine the incidence of group A beta-hemolytic streptococcus (GABHS) carriers in children who are well, in children seen with presumed and documented viral illnesses with sore throat, and in children after treatment of acute GABHS tonsillopharyngitis with 10 days of oral penicillin V potassium, oral cephalosporins, or macrolides. METHODS: Prospective collection of clinical and microbiologic data from October 1996 to June 1997 in a private pediatric practice were obtained from children who were asymptomatic and well, from children with both presumed (and documented) viral sore throats, and from children who had completed a full antibiotic treatment course for acute GABHS throat infections. RESULTS: The incidence of GABHS carriers was 2.5% among well children (n = 227), 4.4% among children with upper respiratory tract infections including sore throat of presumed viral etiology (n= 296), and 6.9% among children with upper respiratory tract infections including sore throat from whom viruses were isolated (n = 87). Following 10 days' treatment of acute GABHS tonsillopharyngitis, 81 (11.3%) of 718 children treated with penicillin, 22 (4.3%) of 508 children treated with an oral cephalosporin, and 10 (7.1%) of 140 children treated with a macrolide were GABHS carriers (P<.001). CONCLUSIONS: A small percentage of children seen in private pediatric practices who are well or who have apparent viral upper respiratory tract infections with sore throat are GABHS carriers. Penicillin treatment of acute GABHS tonsillopharyngitis results in a higher GABHS carriage rate than occurs following treatment with cephalosporins and macrolides.

Administration, Oral↗
PubMed1999

Purification and characterization of a plant antimicrobial peptide expressed in Escherichia coli.

MiAMP1 is a low-molecular-weight, cysteine-rich, antimicrobial peptide isolated from the nut kernel of Macadamia integrifolia. A DNA sequence encoding MiAMP1 with an additional ATG start codon was cloned into a modified pET vector under the control of the T7 RNA polymerase promoter. The pET vector was cotransformed together with the vector pSB161, which expresses a rare arginine tRNA. The peptide was readily isolated in high yield from the insoluble fraction of the Escherichia coli extract. The purified peptide was shown to have an identical molecular weight to the native peptide by mass spectroscopy indicating that the N-terminal methionine had been cleaved. Analysis by NMR spectroscopy indicated that the refolded recombinant peptide had a similar overall three-dimensional structure to that of the native peptide. The peptide inhibited the growth of phytopathogenic fungi in vitro in a similar manner to the native peptide. To our knowledge, MiAMP1 is the first antimicrobial peptide from plants to be functionally expressed in E. coli. This will permit a detailed structure-function analysis of the peptide and studies of its mode of action on phytopathogens.

Anti-Bacterial Agents↗
PubMed1999

Impact of p16 expression on surgical management of malignant melanoma and pancreatic carcinoma.

BACKGROUND: Recent advances in molecular oncology have provided explanations at the DNA level for the malignant transformation and metastatic potential of various cancers. Malignant melanoma and pancreatic cancer may be classified together in both these cancers exhibit mutations in, or loss of, the cell-cycle inhibitory gene, p16. This paper reviews the current literature on p16 expression in melanoma and pancreatic cancer, explores factors that place patients with these cancers in categories of high risk for metastases or recurrence, and addresses whether aberrant gene expressions should influence awareness of and current recommendations for the management of these aggressive cancers. METHODS: A computerized literature search was performed utilizing OVID Technology's Medline database from 1993 to 1998. RESULTS: Both familial as well as sporadic cases of malignant melanoma and pancreatic carcinoma are reported in the literature. Although a low percentage of cases of either malignancy have p16 mutations, a higher risk of their development has been reported to occur in certain families with p16 germline mutations. CONCLUSIONS: The increased risk determined in these families may serve to heighten awareness of the influence of positive family history of these cancers in the evaluation of patients.

Cyclin-Dependent Kinase Inhibitor p16↗
PubMed1999

A family of antimicrobial peptides is produced by processing of a 7S globulin protein in Macadamia integrifolia kernels.

A new family of antimicrobial peptides has been discovered in Macadamia integrifolia. The first member of this new family to be purified from nut kernels was a peptide of 45 aa residues, termed MiAMP2c. This peptide inhibited various plant pathogenic fungi in vitro. cDNA clones corresponding to MiAMP2c encoded a 666 aa precursor protein homologous to vicilin 7S globulin proteins. The deduced precursor protein sequence contained a putative hydrophobic N-terminal signal sequence (28 aa), an extremely hydrophilic N-proximal region (212 aa), and a C-terminal region of 426 aa which is represented in all vicilins. The hydrophilic portion of the deduced protein contained the sequence for MiAMP2c as well as three additional segments having the same cysteine spacing pattern as MiAMP2c. Each member of the MiAMP2 family (i.e. MiAMP2a, b, c and d) consisted of approximately 50 amino acids and contained a C-X-X-X-C-(10-12)X-C-X-X-X-C motif. Subsequent isolations from seed exudates led to the purification of the predicted family members MiAMP2b and 2d, both of which also exhibited antimicrobial activity in vitro. These results suggest that some vicilins play a role in defence during seed germination.

Amino Acid Sequence↗
PubMed1998

Recurrent group A streptococcal tonsillopharyngitis.

OBJECTIVE: To examine the epidemiology and treatment of group A beta-hemolytic streptococcal (GABHS) recurrent tonsillopharyngitis in private pediatric practice. METHODS: This was a retrospective chart review study covering the time span 1975 to 1996 involving 2140 GABHS episodes. Diagnosis was based on acute clinical symptoms and laboratory confirmation (throat culture or positive rapid antigen detection test) of GABHS. RESULTS: Eighty percent (n=1721) of the episodes evaluated were treated with penicillin or amoxicillin; 352 (20.5%) of these were followed by a recurrence within 30 days and 519 (30.2%) within 60 days. GABHS recurrences within 30 days after penicillin/amoxicillin treatment rose from 9% in 1975 to 1979 to 25.9% in 1980 to 1984, 24.2% in 1985 to 1989, 22.4% in 1990 to 1994 and 25.9% in 1995 to 1996 (P < 0.02); 53.4% of the recurrences were associated with symptoms and signs of GABHS tonsillopharyngitis, 9.9% were asymptomatic and 36.7% could not be classified. Recurrences within 60 days after penicillin/ amoxicillin treatment rose from 10.7% in 1975 to 1979 to 38.7% in 1980 to 1984, 39.0% in 1985 to 1989, 31.7% in 1990 to 1994 and 37.5% in 1995 to 1996 (P < 0.001). Recurrent GABHS infections occurred more frequently in younger children (1 to 8 years of age, 21.3% recurrence rate) than in adolescents (13 to 19 years, 5% recurrence rate; P=0.002). Recurrences within 30 days occurred more often after therapy with penicillin (21.8% of 1581 episodes) than with cephalosporins (8.6% of 254 episodes) (P < 0.0001) or with macrolides (14.0% of 143 episodes, P=0.04). Recurrence rates were unaffected by patient gender or season of the year. CONCLUSIONS: Recurrent GABHS infections occur more frequently in the 1990s than the 1970s, occur more frequently in children younger than 8 years of age than in adolescents and occur more frequently after penicillin treatment than with alternative antibiotic therapy.

Adolescent↗
PubMed1997

Purification, characterisation and cDNA cloning of an antimicrobial peptide from Macadamia integrifolia.

An antimicrobial peptide with no significant amino acid sequence similarity to previously described peptides has been isolated from the nut kernels of Macadcamia integrifolia. The peptide, termed MiAMP1, is highly basic with an estimated pI of 10.1, a mass of 8.1 kDa and contains 76 amino acids including 6 cysteine residues. A cDNA clone containing the entire coding region corresponding to the peptide was obtained. The deduced amino acid sequence of the cDNA indicated a 26-amino-acid signal peptide at the N-terminus of the preprotein. Purified MiAMP1 inhibited the growth of a variety of fungal, oomycete and gram-positive bacterial phytopathogens in vitro. Some pathogens exhibited close to 100% inhibition in less than 1 microM peptide (5 microg/ml). Antimicrobial activity was diminished against most, but not all, microbes in the presence of calcium and potassium chloride salts (1 mM and 50 mM, respectively). MiAMP1 was active against bakers yeast, was inactive against Escherichia coli and was non-toxic to plant and mammalian cells. Analysis of genomic DNA indicated that MiAMP1 was encoded on a single copy gene containing no introns. The MiAMP1 gene may prove useful in genetic manipulations to increase disease resistance in transgenic plants.

Amino Acid Sequence↗
PubMed1997

Effects of chronic infusion of angiotensin II on renin and blood pressure in the late-gestation fetal sheep.

OBJECTIVES: Our purpose was to determine whether chronic physiologic elevations in plasma angiotensin II levels decrease plasma renin concentration, alter the relationship between active renin and prorenin in fetal plasma and kidney, and depress the expression of renal renin messenger ribonucleic acid in the fetus. STUDY DESIGN: Seventeen chronically catheterized ovine fetuses at approximately 130 days' gestation were infused with either angiotensin II (48.9 +/- 3.5 ng/kg x min) or vehicle (5% glucose in water) for 72 hours. RESULTS: Mean arterial pressure increased significantly by 1 hour of infusion and continued to increase throughout the infusion. The plasma active renin concentration was significantly decreased by 1 hour of the infusion, whereas the prorenin concentration was not decreased until 24 hours of the infusion. After 72 hours of angiotensin II infusion the renal tissue prorenin content decreased (21.5 +/- 5.1 ng/mg x hr angiotensin I vs 46.4 +/- 6.6 ng/mg - hr angiotensin I in the control animals, p = 0.01), whereas the active renin concentration did not change (26.6 +/- 5.1 ng/mg x hr angiotensin I vs 35.1 +/- 5.4 ng/mg x hr angiotensin I in the control animals, p = 0.28). The renal renin messenger ribonucleic acid expression tended to be lower in the angiotensin II-treated fetuses (p = 0.10). CONCLUSION: Chronic physiologic increases in fetal plasma angiotensin II suppress the secretion of active and prorenin and alter the relationship between processing and secretion of renin in the fetal kidney.

Angiotensin II↗
PubMed1996

Antibody response and reactions to completion of a four-dose series with a two- or three-component acellular pertussis vaccine compared to whole cell pertussis vaccine.

We compared the reactions and immunogenicity of DT acellular pertussis (DTaP) vaccines containing pertussis toxoid (PT) and filamentous haemagglutinin (FHA) (2-component DTaP) or PT, FHA and pertactin (PRN) (3-component DTaP vaccine) with a whole cell (DTwP) vaccine as a fourth-dose booster in 158 children (15-20 months old) who had received 3 primary vaccine doses with the same vaccines at 2, 4 and 6 months of age. Randomization was 3:1 for DTaP:DTwP and all children received concomitant oral polio vaccine (OPV). Fever (> 38 degrees C), irritability, local injection site erythema (> 10 mm), swelling (> 10 mm), and pain (moderate or more) were assessed for 72 h after booster vaccination. DTwP vaccinees had a higher incidence of fever (29.4%) and injection-site pain (45.7%) than 3-component DTaP vaccinees (fever, 9.6%, p < 0.02; injection-site pain, 3.8%, p < 0.01); 2-component DTaP vaccinees had less injection-site pain (8.3%, p < 0.01). Pre- and post-vaccination immunoglobulin G (IgG) antibody was measured by enzyme-linked immunosorbent assay (ELISA). Pre- and post anti-PT levels were similar for all 3 vaccine groups. Anti-FHA antibody was higher pre- and post-vaccination for both DTaP vaccine groups compared with the DTwP vaccinees (p < 0.01 for all comparisons). For 3-component DTaP vaccinees, anti-PRN antibody was higher pre- and post-vaccination compared to DTwP vaccinees (p < 0.01 for both comparisons). Tetanus antibody was higher pre- and post-vaccination for DTwP versus both DTaP vaccine groups, and diphtheria antibody was similar pre- and post-vaccination for all 3 groups. These 2- and 3-component DTaP vaccines produce less common reactions and comparable or higher antibody to the components they contain (except tetanus) than DTwP vaccine when given as a booster to 15- to 20-month-old children previously primed with the same vaccine.

Adhesins, Bacterial↗