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Biomedical subjects

J Hawley

Publications and source records attributed to J Hawley.

18 recordsLinked to original sources
PubMed2000

Assessment of insecticide resistance after the outbreak of diamondback moth (Lepidoptera: Plutellidae) in California in 1997.

During an outbreak of the diamondback moth, Plutella xylostella (L.), in California in 1997, nine populations were collected from the major broccoli areas throughout the state. Populations were assayed for their susceptibility to currently used materials (Bacillus thuringiensis subsp. kurstaki, permethrin, and methomyl) and to newer materials that had not yet been commercially used in California (spinosad, emamectin benzoate, and chlorfenapyr). For the currently used insecticides, elevated levels of resistance were seen only with permethrin and seven of the nine populations had tolerance ratios (TR) of > 100. With the newer chemistries, TR values were all < 15. To compare potential cross-tolerance, TR values of the currently used insecticides were compared with TR values of the newer insecticides. There were significant relationships found between: methomyl and emamectin benzoate, methomyl and spinosad, and permethrin and spinosad. Further biochemical studies are needed to confirm the actual mechanisms that lead to these relationships and field tests are needed to determine what impact, if any, such TR levels would have on control in the field. These data indicate that resistance to at least one of the commonly used insecticides (permethrin) may have played a role in the outbreak during 1997. However, other factors may have been at least equally important. The winter of 1996-1997 was warmer than normal, and during the period from February through August of 1997 the amount of rainfall was < 50% of normal. Hot and dry conditions are known to be conducive to outbreaks of P. xylostella. These data add to an overall knowledge about the geographic variation of resistance in P. xylostella populations within the United States. They also serve as a baseline for monitoring changes in susceptibility to these newer insecticides and can also help explain the occurrence of outbreaks caused by factors other than insecticide resistance.

Animals↗
PubMed1996

Regulation of IgM and IgD heavy chain gene expression: effect of abrogation of intergenic transcriptional termination.

Early IgM+ B cells express little or no membrane IgD due to the low abundance of delta mRNA. Extensive transcriptional termination regulated by sequences in the intronic region between mu and delta heavy chain genes may be the primary reason for the lack of delta gene transcription. We have examined the effect of deletion of these sequences on the regulation of IgM and IgD heavy chain gene expression in transfectants as well as mice carrying this otherwise intact transgene. By run-on transcriptional measurement, we show that the delta exons are transcribed in bone marrow B cells from these transgenic mice. However, in spite of the induced premature synthesis of the full-length mu-delta transcript in pre-B cells, processing to delta mRNA does not occur until the lymphocytes express cell surface IgM. Therefore, during B cell development, synthesis of the full-length transcript is a necessary but not sufficient condition for initiation of delta mRNA synthesis. Furthermore, unexpectedly, the abrogation of transcriptional termination was found to also affect the processing of the primary transcript to microM mRNA. These results show that expression of IgD in primary B cells is stringently regulated and closely linked to IgM expression.

Animals↗
PubMed1996

Pregnancies following high-dose cyclophosphamide with or without high-dose busulfan or total-body irradiation and bone marrow transplantation.

Patients successfully treated with a marrow transplant often have concerns about fertility and pregnancy. This study was performed to determine pregnancy outcome among patients who had received high-dose chemotherapy alone or with total-body irradiation (TBI) and marrow transplantation for aplastic anemia or hematologic malignancy. Records of 1,326 postpubertal and 196 prepubertal patients currently more than 12 years of age after marrow transplant in Seattle from August 1971 to January 1992 were reviewed to determine the patients with normal gonadal function and pregnancies. Among 708 postpubertal women, 110 recovered normal ovarian function and 32 became pregnant. In addition, nine formerly prepubertal girls with normal gonadal function became pregnant. Among 618 postpubertal men, 157 recovered testicular function and partners of 33 became pregnant. An additional two formerly prepubertal men had partners who became pregnant. Forty-one female patients and partners of 35 male patients had 146 pregnancies after transplant. All 76 patients responded to a questionnaire requesting pregnancy history, outcome, infant birth weight, and congenital anomalies information for all clinically recognized pregnancies. There were 115 live births among 146 (79%) pregnancies. Spontaneous abortion terminated four of 56 (7%) pregnancies for 28 female cyclophosphamide (CY) recipients and six of 16 (37%) pregnancies for 13 TBI recipients (P = .02). Partners of 28 male CY recipients had four of 62 (6.4%) pregnancies terminate with spontaneous abortion, but there were no spontaneous abortions among eight pregnancies of five TBI recipients' partners. Preterm delivery occurred for eight of 44 (18%) and five of eight (63%) live births for 24 CY and eight TBI female recipients (P = .01). This 25% incidence among all female patient pregnancies is higher than the expected incidence of 8% to 10% (P = .0001). The 13 preterm deliveries resulted in 10 low birth weight ([LBW] 1.8 to 2.24 kg) and three very low birth weight ([VLBW] < or = 1.36 kg) infants, for an overall incidence of 25%, which is higher than the expected incidence of 6.5% for the general population (P = .0001). Twelve of the 13 premature infants survive. Congenital anomalies were seen among two of 52 (3.8%) live-born infants of female and six of 63 (9.5%) live-born infants of male patients, which is not different from the 13% of single congenital anomalies reported for the general population. These data demonstrate that clinically recognized pregnancies among women who have received a marrow transplant incorporating TBI are likely to be accompanied by an increased risk of spontaneous abortion. Pregnancies among all women who received a marrow transplant are likely to be accompanied by preterm labor and delivery of LBW or VLBW babies who do not seem to be at an increased risk of congenital anomalies. However, determination of possible adverse effects of parental exposure to high-dose alkylating agents with or without TBI on children born posttransplant requires longer, additional follow-up.

Adult↗
PubMed1995

Distribution of receptors mediating phosphoinositide hydrolysis in cultured human umbilical artery smooth muscle and endothelial cells.

Cultures of human umbilical artery smooth muscle and endothelial cells have been established and the effect of a range of calcium-mobilizing receptor agonists on inositol phospholipid hydrolysis has been compared in the two cell types. In human umbilical artery endothelial cells, histamine (EC50 20 microM), ATP (EC50 6.7 microM), sodium fluoride (20 mM) and thrombin (1 U/mL) produced marked increases in [3H]inositol phosphate accumulation. In contrast, bradykinin (1 microM), 5-hydroxytryptamine (5-HT) (0.1 mM) and carbachol (1 mM) produced only a small (< 1% of the response to 1 mM histamine) effect on [3H]inositol phosphate accumulation in these cells. In human umbilical artery smooth muscle cells, histamine (EC50 16 microM), bradykinin (EC50 4.5 nM), 5-HT (EC50 0.7 microM) and carbachol (EC50 21 microM) produced substantial effects (> 20% of the response to 1 mM histamine) on inositol phospholipid hydrolysis while ATP (1 mM) and thrombin (1 U/mL) were much less effective. The response to histamine in both smooth muscle and endothelial cells was antagonized by 50 nM mepyramine (apparent Kd = 5.6 and 2.9 nM in the two cell types, respectively). The response to 5-HT in smooth muscle cells was antagonized by 50 nM ketanserin (apparent Kd = 4.5 nM). In human umbilical artery smooth muscle cells the inositol phosphate response to carbachol was antagonized by 4-diphenylacetoxy-N-methylpiperidine (4-DAMP; pKd = 9.3), atropine (pKd = 9.7), pirenzepine (pKd = 6.7) and methoctramine (pKd = 6.9). These data are consistent with the involvement of an M3-muscarinic receptor in this response. These studies suggest that receptors mediating inositol phospholipid hydrolysis are differentially distributed between human umbilical artery endothelial and smooth muscle cells.

Adenosine Triphosphate↗
PubMed1995

A randomized trial of two preparations of vaginal prostaglandin for pre-induction cervical ripening.

OBJECTIVE: To compare two prostaglandin (PG) E2 preparations for pre-induction cervical ripening in a randomized clinical trial. METHODS: Two milligrams of vaginal PGE2 gel was compared with a vaginal PGE2 3-mg tablet in 200 nulliparous women. Outcomes assessed were induction failure, need for labor augmentation, pain relief requirements, fetal heart rate (FHR) abnormalities, operative delivery rate, induction-to-delivery interval, neonatal condition, and occurrence of uterine hyperstimulation. RESULTS: There was no statistical difference in pre- and post-dose cervical scores. Compared with the tablet group, women in the gel group were more likely to have significant FHR abnormalities in early labor (odds ratio [OR] 4.77, 95% confidence interval [CI] 1.15-19.5) requiring cesarean delivery. Fetal heart rate tracings in the active phase of labor were also more likely to be abnormal in the gel group (chi 2 = 4.31, P < .05). Compared with the gel group, women in the tablet group were significantly more likely to require operative delivery for poor progress in labor (OR 2.83, 95% CI 1.20-7.24). Other clinical outcomes were identical, with no significant differences in the overall rate of failed induction, cesarean delivery, rate of assisted delivery, requirement for oxytocin infusion, induction-to-delivery interval, pain relief requirements, or neonatal condition. CONCLUSIONS: When compared with the PGE2 tablet, the use of PGE2 gel for cervical ripening and labor induction in nulliparous women did not result in significant improvements in labor outcome. Whereas the gel was associated with an increase in significant FHR abnormalities, the tablet was associated with an increase in the rate of operative delivery for poor progress in labor.

Alprostadil↗
PubMed1995

Role of the OCTA site in regulation of IgH chain gene transcription during B cell activation.

We have evaluated the importance of the OCTA site in both the promoter and enhancer regions for the induction of enhancement of IgH chain gene transcription after B cell activation. These studies show that although occupancy of the OCTA site in the promoter is critical for basal transcription of the mu gene, it is not necessary for the increase in transcription induced by in vivo activation. On the other hand, the OCTA site in the enhancer is necessary for neither basal transcription nor in vivo activation of transcription; however, occupancy of this site is required for further up-regulation in transcription of the mu gene in pre-activated cells. These results indicate that different mechanisms may be involved in the activation of resting versus in vivo stimulated B lymphocytes. The findings are discussed in relation to the phenotype described for Oct-2-deficient mice.

Animals↗
PubMed1994

Role of differential mRNA stability in the regulated expression of IgM and IgD.

The expression of IgM and IgD heavy chain mRNA in resting vs activated B cells offers a unique tool for the assessment of the effect of translation on mRNA stability because mu and delta mRNA have identical VDJ sequences but differ substantially in the rest of the molecule. We have shown that despite the 5' UTR identity that allows equal access to the translation machinery, mu mRNA has a significantly higher turnover rate than delta mRNA. However, the short t1/2 of mu mRNA increases significantly after B cell activation. Furthermore, the induction of microS mRNA after B cell activation provides yet another related molecule for comparison. Thus, despite the fact that microS and microM mRNA differ at their 3' ends, they have identical turnover rates in activated B cells. In addition, because the turnover rates of delta mRNA and beta 2 and GAPDH mRNA remain unchanged, these experiments suggest that B cell activation results in the induction of regulatory factor(s) that target specific sequences within mRNA-mu to confer greater stability. They also argue against a more passive regulation of mRNA stability that is a consequence of alterations in the secretory machinery.

Animals↗
PubMed1994

Bradykinin B2- and 5-hydroxytryptamine (5-HT2)-receptor stimulated increases in intracellular calcium in cultured guinea-pig aortic smooth muscle cells.

The effect of 5-hydroxytryptamine (5-HT) and bradykinin on intracellular free calcium concentration ([Ca2+]i) has been studied in cultured guinea-pig aortic smooth muscle cells loaded with the Ca(2+)-sensitive fluorescent dye fura-2. Bradykinin and 5-HT elicited rapid increases in [Ca2+]i with log EC50 values of -7.9 +/- 0.05 M (N = 3) and -6.1 +/- 0.1 M (N = 4), respectively. Both agonists stimulated the release of intracellular calcium (Ca2+ responses still present in the absence of extracellular calcium) and to a lesser extent Ca2+ influx (observed when extracellular calcium was re-applied to cells initially stimulated in nominally Ca(2+)-free buffer containing 0.1 mM EGTA). The B1-receptor antagonist des-Arg9,[Leu8]-bradykinin had no effect on calcium responses elicited 100 nM bradykinin, whereas the B2-receptor antagonist D-Arg[Hyp3,Thi5.8,D-Phe7]-bradykinin (10 microM) inhibited the response to 100 nM bradykinin by 43%. The bradykinin B2-receptor antagonist D-Arg[Hyp3,Thi5.8,D-Phe7]-bradykinin virtually abolished the response to 10 nM bradykinin (IC50 4 microM). No increase in [Ca2+]i was observed with the B1-receptor agonist des-Arg9-bradykinin (300 nM). The response to 5-HT (100 microM) was abolished by the 5-HT2 receptor antagonist ketanserin (IC50 = 2 +/- 0.4 nM; N = 3). These data suggest that in cultured guinea-pig aortic smooth muscle cells bradykinin B2- and 5-HT2-receptor activation stimulates the release of Ca2+ from intracellular stores and Ca2+ influx through Ca2+ entry pathways in the plasma membrane.

Animals↗
PubMed1994

Investigation of the bleeding patterns of postmenopausal women treated with Estrapak-50.

Diary cards of patients in two similar trials of Estrapak-50 hormone replacement therapy were analysed with regard to the characteristics of progestogen-associated bleeding (PAB) and breakthrough bleeding (BTB). Forty out of 52 patients in Study A and 74 out of 92 patients in Study B had diaries suitable for analysis. One patient in Study A and two patients in Study B who withdrew from treatment did so because of unacceptable bleeding problems. Similar results were obtained from both trials. After 6 months of treatment approximately 90% of patients in study A and approximately 70% of patients in study B had PAB on or before day 11. Twenty-seven percent and 49% in studies A and B, respectively, bled prior to day 8, which in the majority of instances affected one treatment cycle. Duration of PAB varied from 1 to 14 days (median 7 days) and the pattern of bleeding in the second cycle was predictive of bleeding in subsequent cycles. Although over 1/3 of women reported some heavy bleeding days, this usually only affected one treatment cycle, and the majority of bleeding was only spotting or light flow. BTB patterns did not raise suspicions of endometrial pathology. Bleeding patterns were both acceptable to patients and, in as much as the current literature indicates that bleeding patterns can be interpreted, were consistent with adequate progestogenic protection of the endometrium.

Administration, Cutaneous↗
PubMed1988

A comparison study of dynamic visual acuity between athletes and nonathletes.

A comparison study of dynamic visual acuity (DVA) was conducted using samples of nonathletic college students and college baseball players. The experimental population consisted of 17 male baseball players ranging in age from 19-24 years. The control population was made up of 25 male graduate students ranging in age from 23-29 years. Subjects reported the direction of a 20/25 "Landolt C" target exhibiting uniform angular motion produced by a projection system. Angular target velocities between 10 deg/sec and 110 deg/sec with an exposure time of 400 ms were used. The results showed a statistically significant difference between the two groups' DVA. The mean DVA for the baseball players was 82.35 deg/sec and 69.90 deg/sec for the control group.

Adult↗
PubMed1986

Calculation of 2,3,7,8-TCDD equivalent concentrations of complex environmental contaminant mixtures.

Sufficient toxicological data are now available to permit use of conventional risk assessment techniques to estimate the hazards associated with human exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD). However, many real-world exposures involve complex mixtures of dibenzodioxins, dibenzofurans, and related compounds. Historical approaches to risk assessment on such mixtures have ranged from ignoring all compounds except 2,3,7,8-TCDD itself to assuming that all compounds have potencies equal to 2,3,7,8-TCDD. An alternative approach which uses existing literature data and analytical results to calculate the "2,3,7,8-TCDD equivalent" concentration of a mixture in order to "predict" its biological potency relative to 2,3,7,8-TCDD itself is advanced here. Previously reported in vivo acute and subchronic studies and some recently obtained analytical chemistry data are integrated here to clarify the utility of this important approach and to assess the uncertainties associated with its use. This predictive approach, and various conceptually similar ones, have now found wide applicability to the risk assessment process associated with exposure to complex mixtures of dioxins, dibenzofurans, and related compounds.

Alanine Transaminase↗