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Biomedical subjects

D M Olson

Publications and source records attributed to D M Olson.

At least 19 recordsLinked to original sources
PubMed2006

Decidual activation: abundance and localization of prostaglandin F2alpha receptor (FP) mRNA and protein and uterine activation proteins in human decidua at preterm birth and term birth.

OBJECTIVE: To study how the decidua contributes to parturition, we examined prostaglandin F(2alpha) concentrations as well as prostaglandin 15-hydroxy dehydrogenase, prostaglandin F(2alpha) receptor, matrix metalloproteinases 2 and 9, oxytocin receptor, prostaglandin-H synthase-2, and the prostaglandin E(2) receptor expression in human decidua. MATERIALS AND METHODS: Decidual samples were isolated from placentas collected from patients at preterm not in labor (PTNIL), preterm labor (PTL), term not in labor (TNIL), and term labor (TL). For immunohistochemistry, fresh membranes which included chorion, amnion and decidua from term patients were collected. RESULTS: Prostaglandin F(2alpha) receptor mRNA was low in all preterm patients and then significantly increased towards term (p=0.049). Prostaglandin F(2alpha) receptor protein was identified in the amnion epithelium and mesoderm, chorion trophoblasts and decidua by immunohistochemistry, and levels were highest at TNIL (p=0.007) as measured by western blot. Prostaglandin F(2alpha) levels were higher at PTNIL than TNIL. Matrix metalloproteinases 2 and 9 protein and pro-enzyme activities were higher at TL than TNIL. There were no significant changes among the groups for any of the other factors measured. CONCLUSIONS: These results suggest that the induction of Prostaglandin F(2alpha) receptor at term may facilitate the decidua contribution to parturition, and its regulation and role should be examined further.

DNA Primers↗
PubMed2005

Changes in matrix metalloproteinase (MMP)-2 and MMP-9 in the fetal amnion and chorion during gestation and at term and preterm labor.

Increased matrix metalloproteinase (MMP)-9 proteolytic activity is associated with term birth, preterm birth and premature rupture of membranes. However, most studies show no changes with MMP-2, which binds tightly to cell and matrix proteins. We hypothesized better protein extraction would reveal new MMP patterns. Human amnion and chorion were collected from 25 patients at preterm or term, extracted with 2% SDS (a high concentration), and the MMP protein levels and pro-enzyme activities were determined by Western immunoblotting and zymography. MMP-2 protein and MMP-2 and -9 pro-enzyme activities in the amnion increased significantly (p<0.05) with labor at term, and were higher than at preterm labor (p<0.05), when extracted with high SDS concentration. There were no changes in chorion MMPs under any condition. These associations suggest MMP-2 may be another regulator of membrane rupture and other labor-associated mechanisms at term parturition, and its role(s) should be examined further.

Adult↗
PubMed2005

Impact of maternal undernutrition and fetal number on glucocorticoid, growth hormone and insulin-like growth factor receptor mRNA abundance in the ovine fetal kidney.

Epidemiological and animal studies strongly indicate that the environment experienced in utero determines, in part, an individual's likelihood of developing cardiovascular disease in later life. This risk has been further linked to impaired kidney function, as a result of compromised development during fetal life. The present study therefore examined the influence of maternal nutrient restriction (NR), targeted at specific periods of kidney development during early to mid gestation, on the mRNA abundance of receptors for glucocorticoid (GCR), growth hormone (GHR) and insulin-like growth factors-I (IGF-IR) and -II (IGF-IIR), and the IGF-I and -II ligands. This was undertaken in both singleton and twin fetuses. At conception ewes were randomly allocated to either an adequately fed control group or one of four nutrient-restricted groups that were fed half the control amount from 0 to 30, 31 to 65, 66 to 110 or 0 to 110 days gestation. At 110 days gestation all ewes were humanely euthanased and fetal kidneys and surrounding adipose tissue sampled. There was no effect of NR or fetal number on kidney weight, shape or nephron number, but the surrounding fat mass was increased in singleton fetuses exposed to NR for 110 days. An increase in kidney mRNA abundance with NR only occurred in singleton fetuses where IGF-IR mRNA was enhanced with NR from 66-110 days gestation. In twin fetuses, NR had no effect on mRNA abundance. However, for all genes examined mRNA expression was lower in the kidneys of twin compared with singleton fetuses following NR, and the magnitude of the effect was dependent on the timing of NR. In conclusion, the abundance of mRNA for receptors which regulate fetal kidney development are lower in twin animals compared with singletons following periods of nutrient deficiency. This may impact on later kidney development and function.

Animals↗
PubMed2003

Inheritance of host finding ability on structurally complex surfaces.

The connectivity of a surface (structural complexity) can have a significant effect on the host finding behavior and efficiency of parasitoids that must search the surface for hosts. We investigated whether the generalist egg parasitoid, Trichogramma nubilale Ertle and Davis (Hymenoptera: Trichogrammatidae), found hosts more efficiently on simple or complex surfaces, and evaluated the potential genetic basis of this variation using a full-sib/ half-sib mating design. Of the egg masses parasitized 63.8% were on the simple surface while only 36.2% were on the complex surface. There was significant repeatable variation among females (repeatability =0.59, n=19 females), with some better at finding hosts on simple surfaces and others better on complex surfaces. These results reinforce previous findings that structural complexity can affect host finding by parasitoids. The additive genetic variance in this character was not significant (sires =23, dams =46, progeny =92), but the maternal plus dominance variance ( V(m)+1/2 V(d)) was significant (P<0.036), and accounted for 48.8% of the total phenotypic variance. The maternal or dominance effects could have complex evolutionary consequences, causing the evolution of other foraging traits to be retarded, to overshoot their optima, or to have complex selective regimes. Thus, the evolution of foraging behavior may depend strongly on the mechanistic details of foraging behavior, including the effects of structural complexity on host finding.

Animals↗
PubMed2003

Myometrial activation and preterm labour: evidence supporting a role for the prostaglandin F receptor--a review.

An increase in the myometrial expression of the prostaglandin (PG) receptors, and especially the PGF(2alpha) receptor (FP), may be an important component of the process initiating preterm labour. In this review of the literature and presentation of new possibilities, evidence will be discussed that demonstrates an increase in mouse uterine FP mRNA occurs at preterm birth whereas uterine PGF(2alpha) concentrations do not increase, suggesting elevated uterine receptor expression and sensitivity is a mechanism for preterm labour initiation. The first examination of the complete human myometrial FP promoter will be described and evidence presented that demonstrates the pro-inflammatory cytokine, interleukin-1beta, stimulates FP mRNA expression. Finally new data showing that administration of a specific FP antagonist delays preterm birth in sheep will be presented.

Animals↗
PubMed2003

Parasitic wasps learn and report diverse chemicals with unique conditionable behaviors.

Parasitoids exploit numerous chemical cues to locate hosts and food. Whether they detect and learn chemicals foreign to their natural history has not been explored. We show that the parasitoid Microplitis croceipes can associate, with food or hosts, widely different chemicals outside their natural foraging encounters. When learned chemicals are subsequently detected, this parasitoid manifests distinct behaviors characteristic with expectations of food or host, commensurate with prior training. This flexibility of parasitoids to rapidly link diverse chemicals to resource needs and subsequently report them with recognizable behaviors offers new insights into their foraging adaptability, and provides a model for further dissection of olfactory learning related processes.

Animals↗
PubMed2002

Inheritance of an oviposition behavior by an egg parasitoid.

A quantitative genetic study revealed genetic and environmental sources of variance in percentage parasitism of European corn borer egg masses and secondary sex ratios by Trichogramma nubilale. Full and half-sib groups of T. nubilale were obtained from a nested mating design, which permitted the partitioning of the variance of T. nubilale parasitism of European corn borer egg masses into additive genetic variance, maternal/dominant variance and environmental variance. A mother-daughter regression of the percentage of an egg mass parasitized allowed a determination of the direction of a potential response to selection in the event of maternal effects. No or very little additive genetic effects were associated with the percentage of eggs within a mass parasitized and secondary sex ratios, but a significant amount of the variance for both traits had a maternal and/or dominant genetic source. The relationship between mothers and daughters in egg mass parasitism was positive, and 55.4% of the progeny of a given mother had behaviors that resemble their mother. Most of the variance had an environmental and/or unknown genetic source implying potentially high phenotypic plasticity associated with all these traits. The presence of maternal effects and phenotypic plasticity could have multiple and complex effects on progeny characters and potential responses to selection.

Animals↗
PubMed2001

Ecology. Giant pandas in a changing landscape.

The giant panda has been restricted to several disjunct montane forest populations, and habitat loss and fragmentation are the primary threats to its survival. For pandas to survive, conservation efforts must focus on larger landscapes rather than individual nature reserves. China recently initiated several policies, including the Natural Forest Conservation Program and Grain-to-Green Policy, which provide a historic opportunity to integrate panda conservation into national policies. Simultaneously, China is promoting the Western China Development Program, which calls for substantial infrastructure and hydropower development and economic investments. Integrating panda conservation into these development policies will be a critical challenge.

Animals↗
PubMed2001

Prostaglandin endoperoxide H synthase type 1 and type 2 messenger ribonucleic acid in human fetal tissues throughout gestation and in the newborn infant.

OBJECTIVE: We determined the relative abundance of prostaglandin endoperoxide H synthase type 1 and type 2 messenger ribonucleic acid levels in the human fetus and newborn infant. STUDY DESIGN: We used ribonuclease protection assays and normalized values to messenger ribonucleic acid of cyclophilin. Tissues were obtained from all 3 trimesters and in the first 9 days of the newborn period. RESULTS: Prostaglandin endoperoxide H synthase type 1 and type 2 messenger ribonucleic acid is present in every fetal tissue examined (lung, kidney, intestine, heart, brain, and stomach). Kidney and lung demonstrated no changes in the expression of prostaglandin endoperoxide H synthase type 1 messenger ribonucleic acid with gestational age, whereas postnatal levels in lung were one third those in the first trimester (P <.05). A large increase (5-fold to 30-fold; P <.05) occurred throughout gestation for the expression of prostaglandin endoperoxide H synthase type 2 messenger ribonucleic acid in intestine, lung, and kidney, which extended into the newborn period for lung and kidney. CONCLUSIONS: These data imply that the expression of prostaglandin endoperoxide H synthase type 2 messenger ribonucleic acid may be responsible for prostaglandin-related effects and is coordinated in several human fetal tissues in late gestation.

Brain↗
PubMed2001

Success of ambulatory EEG in children.

SUMMARY: Continuous ambulatory EEG (AEEG) monitoring is a method used to (1) determine seizure type and location of seizure onset, and (2) to discriminate between epileptic and nonepileptic events. This study was performed to determine how successful AEEG would be in recording seizures when the events were reported to occur at least 3 days per week. AEEGs of children who were patients at Children's Hospital Oakland between December 1993 and June 1997 were reviewed to see why the recordings were performed and to determine whether typical seizures were recorded. Children who had seizurelike events needed to have typical spells 3 days or more per week to justify obtaining AEEG. Most AEEGs were performed to discriminate between epileptic and nonepileptic seizures. A total of 167 children underwent AEEG recording. Ten were recorded to determine whether they were having frequent subtle seizures or frequent interictal epileptiform discharges. The remaining 157 patients had discrete events. A total of 140 children (89%) had their typical spells recorded. A total of 107 of these children (76%) had nonepileptic events. Average duration of recording was 1.9 days. AEEG is very successful in recording children's seizurelike events when parents report events occur at least 3 days per week. The procedure is well tolerated and there are few technical problems that prolong recording time.

Adolescent↗
PubMed2001

Timing of hyperoxic exposure during alveolarization influences damage mediated by leukotrienes.

Hyperoxic exposure of rat pups during alveolarization (postnatal days 4-14) severely retards alveolar development. Some aspects of this inhibition are mediated by leukotrienes (LTs) and may be time sensitive. We determined 1) the effects of exposure to hyperoxia (O(2)) during discrete periods before and during alveolarization on developing alveoli and 2) whether a relationship exists between O(2) and LTs in these periods. Pups were exposed to >95% O(2) from days 1 to 4, 4 to 9, 9 to 14, or 4 to 14 in the absence and presence of the LT synthesis inhibitor MK-0591. Both the level of in vitro lung tissue LT output on days 4, 9, and 14 and the degree of alveolarization on day 14 were determined. Pups exposed to O(2) from days 4 to 9 had a more profound inhibition of alveolarization on day 14 compared with those exposed to O(2) from days 1 to 4 or 9 to 14. Peptido-LT levels were significantly higher in pups exposed to O(2) on days 9 and 14 compared with pups in air and returned to normal once normoxia was restored. LT inhibition from days 4 to 14, 4 to 9, or 9 to 14 in pups exposed to O(2) from days 4 to 14 prevented the O(2)-induced inhibition of alveolarization. These data suggest that developing alveoli are sensitive to LTs shortly before and after day 9, significantly retarding certain parameters of alveolarization on day 14. We conclude that some of the effects of O(2) are not uniform throughout different stages of alveolarization and that this is likely related to the timing of LT exposure.

Age Factors↗
PubMed2001

Evaluation of children for epilepsy surgery.

There are three main components to the evaluation of children who are candidates for epilepsy surgery: (1) confirmation of the epileptic nature of the seizures, (2) establishing the medical intractability of the child's epilepsy and (3) localization of the epileptogenic zone. Differentiating epileptic from nonepileptic events requires careful review of the history and the electroencephalogram. Electroencephalographic recording of the habitual seizures usually suffices to confirm the epileptic or nonepileptic nature of the events. Medical intractability is established by assuring that antiepileptic medications appropriate for the child's particular epilepsy syndrome have been used and have been titrated to maximum tolerance before being deemed ineffective. Confident localization of the epileptogenic zone requires that multiple findings such as behavior during the seizure, ictal and interictal EEG, and cerebral imaging studies provide data that are convergent with respect to a likely area of seizure onset.

Child↗
PubMed2001

Sedation of children for electroencephalograms.

OBJECTIVE: Sedation sometimes is necessary to perform an electroencephalogram (EEG) on a child. A dramatic decline in the need to use conscious sedation in our EEG laboratory prompted this review of our sedation experience. The purpose of this review was to determine the incidence of adverse sedation effects and to determine why the need for sedation had declined. METHODS: All 513 attempts to administer sedation to children who were undergoing EEG studies during a 4-year period were reviewed retrospectively. Parameters studied included type and amount of the sedative agents, need for repeated dosing, successful completion of the EEG, and complications attributed to the sedative. RESULTS: Sedation was attempted in 513 (18%) of 2855 EEGs performed during the 4-year period. Ninety-one percent of the EEGs performed with sedation were completed successfully. Chloral hydrate was the most frequently administered sedative. Complications (transient oxygen desaturation) occurred in 3 children, all of whom had recognized risk factors for airway compromise. The proportion of children who required sedation decreased from 32% to just 2% during that time period. CONCLUSION: Sedation of children who are undergoing EEG examinations is effective and safe. Complications are infrequent. The need for sedation can be decreased greatly by adequate preparation and by creating a less-threatening, child-friendly environment in which to perform the study.

Adolescent↗
PubMed2001

Quiet time: a nursing intervention to promote sleep in neurocritical care units.

BACKGROUND: Patients in intensive care units are often sleep deprived, yet little research exists on the impact of nursing care on promoting sleep. OBJECTIVES: To determine if implementing a "quiet time" protocol to reduce external environmental stimuli is associated with increased frequency of sleep among patients in a neurocritical care unit. METHODS: Patients were observed 8 times each day before and after implementation of a protocol in which environmental sounds and lights were decreased from 2 AM to 4 AM and from 2 PM to 4 PM. Data collected at 2:45 AM, 3:30 AM, 2:45 PM, and 3:30 PM on patients with scores of 10 or greater on the Glasgow Coma Scale were analyzed. A total of 2975 observations were made on a total of 239 patients: 1446 observations on 118 patients in the control group and 1529 observations on 121 patients in the intervention group. RESULTS: The percentage of patients observed asleep was significantly higher during the months the quite-time period was implemented than during the control period before the intervention was started. The increase in sleep behavior was associated with decreased sound and light levels achieved during the quiet time. Patients observed during the intervention period were 1.6 times more likely to be asleep during the quiet time than were patients observed during the control period (P < .001). CONCLUSIONS: A concentrated effort by staff to reduce environmental stimuli at discrete preset intervals increases the likelihood of sleep during scheduled quiet time in the neurocritical care unit.

Critical Care↗
PubMed2000

Prostaglandin endoperoxide H synthase mRNA expression in the fetal membranes correlates with fetal fibronectin concentration in the cervico-vaginal fluids at term: evidence of enzyme induction before the onset of labour.

OBJECTIVE: To determine the relationship of prostaglandin endoperoxide H synthase (PGHS) expression in the gestational tissues and fetal fibronectin in cervico-vaginal fluids before the onset of labour at term. DESIGN: Cross-sectional, observational study. SAMPLES: Amnion, chorion laeve and decidua were collected from 24 term pregnant women following elective caesarean section. Samples of cervico-vaginal secretions were obtained from the same women immediately before caesarean section. METHODS: PGHS-1 and PGHS-2 mRNA levels in tissues were determined by specific ribonuclease protection assays. Fetal fibronectin concentrations in the cervico-vaginal fluids were measured by enzyme-linked immunosorbent assay. The abundance of PGHS mRNA was compared between groups of patients with the same mean gestational age but different cervico-vaginal fetal fibronectin levels. Linear regression analysis was used to determine the association between PGHS levels and fetal fibronectin. RESULTS: Two groups of women were identified who had significantly different fetal fibronectin values but the same gestational ages. The group with the higher fetal fibronectin concentrations had significantly higher PGHS- 1 and PGHS-2 mRNA levels in the chorion laeve and higher PGHS-2 mRNA levels in the amnion, than the group with lower fetal fibronectin concentrations. PGHS- 1 and PGHS-2 mRNA levels in the chorion laeve and PGHS-2 mRNA in the amnion showed an overall significant association with fetal fibronectin levels. CONCLUSIONS: High concentrations of fetal fibronectin in cervico-vaginal secretions before the onset of spontaneous labour at term are associated with high levels of PGHS-2 mRNA in the chorion laeve and the amnion and of PGHS- 1 mRNA in the chorion laeve. Increased expression of PGHS in these tissues may therefore be involved in the events leading to term birth.

Amnion↗
PubMed2000

Expression of myometrial activation and stimulation genes in a mouse model of preterm labor: myometrial activation, stimulation, and preterm labor.

Myometrial contractions of labor result from an increase in myometrial activation and stimulation. Activation develops through the expression of contraction associated proteins (CAPs), including oxytocin receptors (OTR), connexin-43 (Cx-43), and prostaglandin F2 alpha, receptors (FP). Stimulation involves increases in contractile agonists including prostaglandin E2 (PGE2) and prostaglandin F2 alpha. (PGF2 alpha) that may result from increases in prostaglandin endoperoxide H synthase (PGHS)-2. A mouse model of preterm birth was used to study gene expression involved in myometrial activation and stimulation. To induce preterm birth, pregnant C57BL/6J mice were intubated with 6 g/kg ethanol on gestational day 16 and were killed every 6 h from treatment until birth. RIA was used to measure uterine PGE2 and PGF2 alpha, while PGHS-2, OTR, Cx-43, and FP messenger RNA levels were measured by ribonuclease protection assay. Increases in CAP mRNA were associated with term and preterm birth. There were differences in stimulation effectors associated with preterm and term birth. Uterine PGF2 alpha values were increased only at the time of term birth, but PGE2 was elevated during both preterm and term labor. These data suggest that existing levels of PGF2 alpha are sufficient for preterm birth when CAP expression is increased, but term labor requires increases in PGE2, PGF2alpha, and CAPs. The PGHS-2 messenger RNA expression pattern suggests that it is a CAP.

Animals↗
PubMed2000

Frequency of resistance to Bacillus thuringiensis toxin Cry1Ab in an Iowa population of European corn borer (Lepidoptera: Crambidae).

The refuge plus high-dose strategy for resistance management assumes that the frequency of resistance alleles is low. We used an F2 screen to estimate the frequency of resistance to transgenic corn that produces Bacillus thuringiensis Berliner Cry1Ab toxin (Bt corn) in an Iowa population of European corn borer, Ostrinia nubilalis (Hübner). We also proposed a modification to the statistical analysis of the F2 screen that extends its application for nonuniform prior distributions and for repeated sampling of a single population. Based on a sample of 188 isofemale lines derived from females caught at light traps during the 2nd flight of 1997, we show with 95% confidence that the frequency of resistance to Bt corn was <3.9 x 10(-3) in this Iowa population. These results provide weak evidence that the refuge plus high-dose strategy may be effective for managing resistance in O. nubilalis to Bt corn. Partial resistance to Cry1Ab toxin was found commonly. The 95% CI for the frequency of partial resistance were [8.2 x 10(-4), 9.4 x 10(-3)] for the Iowa population. Variable costs of the method were 14.90 dollars per isofemale line, which was a reduction of 25% compared with our initial estimate.

Alleles↗