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Biomedical subjects

O W Jones

Publications and source records attributed to O W Jones.

At least 19 recordsLinked to original sources
PubMed2006

Medical management of radiation injuries: current approaches.

The current approach to medical management of irradiated patients begins with early diagnosis of radiation injury. Medical assessment of radiation dose is based on event history, symptomatology and laboratory results, with emphasis on time to emesis and lymphocyte depletion kinetics. Dose assessment provides a basis for early use of haematopoietic growth factors that can shorten the period of neutropaenia for patients with acute radiation syndrome. Assessments of haematopoietic, gastrointestinal and cutaneous syndromes have improved in recent years, but treatment options remain limited. Selected examples of current developments are presented.

Accidents, Occupational↗
PubMed2000

Attitudes of physicians regarding receiving and storing patients' genetic testing results for cancer susceptibility.

In order to determine interest in and support for a genetic counseling program for heritable cancers, a four-item questionnaire was sent to 700 physicians in San Diego County likely to encounter patients with significant family histories of cancer. Included in the questionnaire was an item requesting information about physician attitudes and practices regarding their record keeping for patient results of genetic testing for cancer susceptibility. Ninety-two questionnaires were returned for a response rate of 13%. The low response rate introduces caution when interpreting the results, particularly if the physicians most interested in the topic were the most likely to respond. In this light, of note was the marked variability found in the attitudes of respondents regarding where the results of patients' genetic testing results should be placed in relation to the medical record. Whereas one group of physicians would place the testing results into the medical record, just as they would any laboratory test result, other physicians do not even want written notice of the results in order to maintain patient confidentiality. Another group acknowledges the sensitivity of the information, but prefers to store genetic testing results separately, as they would results of HIV testing or history of psychiatric treatment. Genetic testing for cancer susceptibility is associated with patient concerns regarding confidentiality of testing results and fears of the consequences of release of this information to insurance companies. While the small and possibly biased sample must be considered when interpreting the results, the lack of consistency among physicians about where to store genetic testing results in terms of the patient medical record underscores the need for both a consensus statement and legal protection for both patient and physician. Variability in physician practices suggests that the process of obtaining informed consent for genetic testing should include a discussion with the patient about how the confidentiality of test results will be maintained.

Attitude of Health Personnel↗
PubMed1999

The effect of spinal anesthesia on the success rate of external cephalic version: a randomized trial.

OBJECTIVE: To identify the effect of spinal anesthesia on the success rate of external cephalic version after 36 weeks' gestation. METHODS: Women with singleton breech presentations after 36 weeks' gestation were offered enrollment. Those who agreed were randomized to receive spinal anesthesia or no anesthesia. Up to four attempts were made using ultrasound surveillance. External cephalic version was terminated with patient discomfort or fetal heart decelerations. Statistical analysis based on intent-to-treat was performed using chi2, Student t tests, and multivariate analysis. Sample size projection based on 20% difference in success rate from a baseline of 50% indicated a need for 50 women in each group. RESULTS: One hundred two women were entered in the study from October 1993 to August 1997. There were no differences between groups in parity, maternal age, amniotic fluid index, gestational age, birth weight, placental location, type of breech presentation, maternal weight, or gestational age at delivery. Forty-four external cephalic versions were successful. Fifty (49%) women received spinal anesthesia, and 52 (51%) did not; there was no difference in the overall success rate between groups (44% spinal versus 42% no spinal). Spontaneous version occurred before external cephalic version was attempted in four patients in the spinal group (after the spinal was given) and one patient in the no-spinal group. These patients were included in the analysis. CONCLUSION: Spinal anesthesia does not increase the external cephalic version success rate in singleton pregnancies with breech presentations after 36 weeks' gestation.

Adult↗
PubMed1996

Complete hydatidiform mole with a coexistent embryo.

We describe a case of a complete hydatidiform mole with a coexistent embryo. A 19-year-old Hispanic woman presented with an intrauterine pregnancy at 7 weeks gestational age. An ultrasound evaluation at that time showed a gestational sac and fetal heart activity was observed. Four weeks later, subsequent ultrasound study revealed no evidence of an embryo, and a pattern consistent with a hydatidiform mole. Dilation and curettage was subsequently performed that showed a classic hydatidiform mole on histological examination. Chromosome analysis revealed a normal 46,XX karyotype. DNA was extracted from the placental tissue, as well as maternal and paternal blood. Molecular genetic analysis was; performed with four variable number of tandem repeats (VNTR) probes and showed the placental tissue to consist of only paternal DNA with two genomic copies of each allele studied. These findings are consistent with the diagnosis of complete hydatidiform mole and its origin from an empty ovum fertilized by a single sperm. This is the first reported case of a living embryo coexistent with a complete hydatidiform mole documented by genetic analysis.

Adult↗
PubMed1995

Ultrasonographic assessment of fetal growth: comparison between human and ovine fetus.

OBJECTIVE: Our purpose was to evaluate the rate of ovine fetal growth for several body parameters by serial ultrasonographic measurements and to compare them with analogous data in the human fetus. STUDY DESIGN: Forty-three ewes with singleton gestations were studied. Four parameters were measured: biparietal diameter, abdominal circumference, femur length, and tibia length. Ultrasonographic examinations were performed weekly from 50 to 138 days of gestation (term 147 days). Quadratic regression analysis was used to describe each data set. RESULTS: The biparietal diameter showed a significant deceleration of its growth rate. The abdominal circumference showed a linear growth pattern. Both femur and tibia revealed a significant acceleration of the growth rate. CONCLUSION: The ovine fetal growth pattern is different from that observed in the human fetus, in which all four parameters show deceleration of the growth rate in late gestation. In comparison to the ovine, the human fetus reaches similar abdominal circumference and femur length values at term, but in a gestational period that is twice as long. In sharp contrast to abdominal circumference and femur length growth, the biparietal diameter has a similar growth rate in both species. Thus the human fetus has a slower rate of somatic growth and its greater biparietal diameter at term results from the longer gestational period.

Abdomen↗
PubMed1995

Early ultrasonographic detection of fetal growth retardation in an ovine model of placental insufficiency.

OBJECTIVE: Our aims were as follows: (1) to determine whether fetal growth retardation can be detected noninvasively with ultrasonography in ewes and (2) to establish the time interval between exposure of ewes to environmental stress that causes growth retardation (heat stress) and detection of growth lag for specific fetal body measurements. STUDY DESIGN: Four ewes were exposed to heat stress for 80 days starting at 35 days' gestation. (The duration of pregnancy in sheep is 147 days). Serial ultrasonographic measurements of fetal biparietal diameter, abdominal circumference, and femur and tibia lengths were obtained beginning at 50 days' gestation. Growth curves were calculated for each parameter and compared with growth curves obtained from 43 normal fetuses. RESULTS: Biparietal diameter measurements deviated significantly from normal starting at 90 days' gestation (p < 0.05). Abdominal circumference diverged at 70 days' gestation (p < 0.05), and both femur and tibia length diverged at 80 days (p < 0.05). The regression lines showed significant differences for all the parameters in both slope (p < 0.01) and intercept (p < 0.01). CONCLUSIONS: Fetal growth retardation can be detected noninvasively by ultrasonography after approximately 5 weeks of exposure to heat stress. Fetal growth continues throughout gestation but at a slower rate than normal and according to a pattern similar to that observed in asymmetrically growth-retarded human fetuses. Early detection of stunted fetal growth in an animal model is important for testing intervention strategies in the treatment of fetal growth retardation.

Abdomen↗
PubMed1995

Assessing the acceptability of Norplant contraceptive in four patient populations.

The object of this study was to review the experience of Norplant implants insertion at the University of Colorado Health Sciences Center with specific attention to the potential impact of source of care and/or clinic site of of insertion. Norplant implants were inserted at four different office sites, namely, adolescent-teen, resident, certified nurse midwife, and faculty physician. The charts of all patients who had Norplant implants inserted between April 1991 and September 1992 were reviewed and we attempted to contact each patient by telephone to assess clinical course and acceptability of Norplant contraceptive. We were able to contact 254 of 414 women (61%) who had Norplant implants inserted. The average length of time since Norplant implants insertion was 13.2 months. The only significant demographic difference between groups was that the adolescent-teen patients were younger, of lower parity, less educated, and were more likely to be single than the other three groups. The overall removal proportion was 14.6%, and removal proportions were not significantly different between any of the four groups. The primary reason for removal was unacceptable bleeding (32% of removers). Only 59% of patients returned for follow-up care. Faculty physician patients were significantly more compliant with follow-up compared to adolescent-teen and resident patients (p < 0.01). Patient retention of Norplant contraceptive is unrelated to age or the clinic setting in which the device was inserted. Since similar side effects are experienced by retainers and removers, it is unclear what other factors prompt women to seek removal. Particularly in the teen and resident groups, follow-up is poor.

Adolescent↗
PubMed1994

Transvaginal ultrasonography and transabdominal embryoscopy in the first-trimester diagnosis of Smith-Lemli-Opitz syndrome, type II.

OBJECTIVE: Our goal was to demonstrate the efficacy of transabdominal embryoscopy in the first trimester of pregnancy. STUDY DESIGN: A patient at risk for Smith-Lemli-Opitz syndrome, type II, was referred for prenatal diagnosis at 11 weeks 5 days of gestation. RESULTS: A transvaginal ultrasonographic examination revealed the presence of a nuchal membrane and bilateral polydactyly. A transabdominal embryoscopy confirmed the diagnosis of polydactyly. The patient had an unremarkable postprocedure course before termination of pregnancy 5 days later. In a second pregnancy embryoscopy revealed a normal fetal hand despite a suggestion on transvaginal ultrasonography that there was polydactyly. On the basis of this information the patient elected to continue the pregnancy, and a normal baby was delivered at 35 weeks. CONCLUSION: This case validates the efficacy of noninvasive and invasive techniques, used adjunctively, in the first-trimester diagnosis of a lethal fetal condition composed of subtle phenotypic manifestations.

Abnormalities, Multiple↗
PubMed1994

Systemic and pulmonary hemodynamic effects of big endothelin-1 and phosphoramidon in the ovine fetus.

To investigate the potential role of endothelin-1 (ET-1) in fetal vasoregulation, we examined in sheep the hemodynamic effects of infusion of big ET-1 (bET-1; precursor of ET-1) on the systemic and pulmonary circulations in chronically catheterized late-gestation fetuses. Thirteen animals [134 +/- 0.5 (SE) days gestation] received systemic infusions of bET-1 (1.5 or 3.0 micrograms/min for 10 min via the superior vena cava), which increased systemic arterial pressure by 5.0 +/- 1.9 (P < 0.01) and 13.9 +/- 1.8 mmHg (P < 0.01), respectively. Pretreatment with 10 mg of phosphoramidon, an ET-1-converting enzyme inhibitor, blocked the hypertensive response to bET-1. Six animals (136 +/- 1.5 days gestation) received intrapulmonary infusion of bET-1 (3.0 micrograms/min for 10 min via the left pulmonary artery), which increased pulmonary arterial pressure by 18.1 +/- 1.5 mmHg (P < 0.01). Three animals (130 +/- 1.5 days gestation) received phosphoramidon (1 mg/min for 10 min via the left pulmonary artery), which had no observed effect on baseline pulmonary vascular tone. We conclude that bET-1 produces systemic and pulmonary hypertension in the late-gestation fetus. Phosphoramidon inhibits bET-1-induced hypertension, suggesting that the fetus possesses ET-1-converting enzyme activity.

Animals↗
PubMed1992

Characterization of mutations in phenotypic variants of hypoxanthine phosphoribosyltransferase deficiency.

The Lesch-Nyhan disease is caused by an almost complete lack of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT). Partial HPRT-deficiency, associated with less severe phenotype, has also been identified. We have characterized mutations occurring in HPRT cDNA isolated from patients with HPRT-deficiency with an emphasis on examining the more unusual partial variants of HPRT-deficiency. HPRT cDNA was amplified by PCR, cloned and analyzed by automated DNA sequence analysis. Twenty-two, unrelated individuals with HPRT deficiency were studied including eight classic Lesch-Nyhan patients and fourteen patients representing the different groups of partial HPRT deficiency. We found a diverse pattern of mutations with point mutations accounting for the majority of abnormal HPRT genes. Nonsense mutations and exon deletions were only found in HPRT cDNA isolated from classic Lesch-Nyhan patients. Mutations associated with partial HPRT-deficiency were frequently located in the amino terminal part of the molecule. A CpG mutational hot spot was identified at the position for Arg-51 in the HPRT protein. Two hyperuricemic patients exhibited unusual splice site mutations: in one this led to the creation of an additional exon in the HPRT gene and in the other part of exon 6 was missing in a subpopulation of the transcripts, producing the effect of a dominant, negative mutation.

Amino Acid Sequence↗
PubMed1991

Enhancement of amniocyte growth on a precoated surface.

This study investigates whether cell-free amniotic fluid facilitates cell attachment to the surface of culture plates and thereby promotes rapid amniocyte growth. Isolated or pooled cell-free amniotic fluid samples at different volumes were added to culture plates. Trypsinized subcultures, grown in Eagle's minimum essential alpha medium supplemented with fetal bovine serum (4-20 per cent), were monitored by cell counts. The results demonstrated growth stimulation on culture plates precoated with amniotic fluid. The minimal time for coating the culture plates was 6 h. Maximal coating was observed after an overnight incubation with 2-3 ml of the fluid per culture vessel. No synergistic effect from addition of fetal bovine serum to amniotic fluid was observed. A freshly coated surface provided the best amniocyte growth. When primary cultures are grown on a precoated surface, there is an increase in colony counts in 80 per cent of the samples tested. This method may be used to improve amniocyte growth, especially in samples with relatively small numbers of cells.

Age Factors↗
PubMed1991

Prospective evaluation of maternal serum human chorionic gonadotropin levels in 3428 pregnancies.

As part of a multicenter prospective study, second-trimester human chorionic gonadotropin and alpha-fetoprotein concentrations were evaluated. Data included maternal age, human chorionic gonadotropin level, alpha-fetoprotein level, weight, race, and pregnancy outcome of 3428 pregnancies at between 15 and 20 weeks' gestation. The results of the study indicate that human chorionic gonadotropin levels decrease as maternal weight increases, that weight-adjusted human chorionic gonadotropin levels for Oriental and black women are higher than for white or Hispanic women, and that twin pregnancies have higher human chorionic gonadotropin levels than singleton pregnancies. Of 255 pregnancies that did not have normal outcomes, 54 (21.2%) had human chorionic gonadotropin levels greater than 2.0 multiples of the median and 26 (10.2%) had alpha-fetoprotein levels greater than 2.5 multiples of the median. Of 11 pregnancies with fetal aneuploidy, 6 (54.5%) had human chorionic gonadotropin levels greater than 2.0 multiples of the median. It is concluded that in human chorionic gonadotropin screening programs for fetal Down syndrome, weight and race adjustments are necessary for accurate risk assessment.

Aneuploidy↗
PubMed1991

Dose-dependent effects of angiotensin II on the ovine fetal cardiovascular system.

The purpose of this experiment was to establish dose-response relationships for the effects of angiotensin II on arterial pressure, venous pressure, heart rate, and blood volume in the ovine fetus. Chronically catheterized fetal sheep at 132 +/- 1 (SE) days' gestational age were infused with angiotensin II at 4.8 +/- 1.1 (n = 7), 27.7 +/- 4.6 (n = 7), 102.2 +/- 16.7 (n = 6), or 239.0 +/- 30.9 (n = 4) ng/min/kg fetal body weight for 30 minutes. Fetal arterial pressure increased at the three highest doses. Fetal venous pressure, heart rate, and blood volume responded only at 102.2 and 239.0 ng/min/kg. At 239.0 ng/min/kg, arterial pressure increased by 17.7 +/- 1.6 mm Hg (p less than 0.00001), venous pressure increased by 1.5 +/- 0.3 mm Hg (p less than 0.0005), blood volume decreased by 7.8 +/- 2.2% (p less than 0.0001), and heart rate initially decreased by 14 +/- 4 beats/min, followed by an increase of 52 +/- 17 beats/min from control (p less than 0.0005) at the end of angiotensin II infusion. Thus this study shows that angiotensin II affected multiple fetal cardiovascular variables in a dose-dependent manner, suggesting that it is an important regulatory hormone for the entire fetal cardiovascular system.

Angiotensin II↗
PubMed1991

Retinoblastoma cell lines Y79, RB355 and WERI-Rb27 are genetically related.

Genesis of the childhood ocular tumor retinoblastoma results from the mutational inactivation of a single gene, RB, located on chromosome 13. Cultured cells or cell lines derived from retinoblastomas have been extensively studied for insight into mutational mechanisms of RB inactivation, functional properties of wild-type RB alleles, and pathways of retinal differentiation. Three such cell lines (Y79, RB355 and WERI-Rb27) were previously shown to have similar, heterozygous rearrangements of their RB genes, suggesting a common mutational mechanism affecting a specific region of the gene. This proposal was based on the premise that all three mutations occurred independently. By using molecular analyses of human genetic polymorphisms, we now show that these three cell lines are in fact genetically related, despite their different origins, morphologies, growth characteristics, and karyotypes. Interpretation of these and other published data suggest that both RB355 and WERI-Rb27 are probably sublines of Y79.

Blotting, Southern↗
PubMed1990

Characterization of a factor-dependent acute leukemia cell line with translocation (3;3)(q21;q26).

A strictly factor-dependent cell line (UCSD/AML1) was established from a patient with the syndrome of multilineage acute leukemia with high platelets. The patient's cells and the cell line karyotype were 45,XX,-7,t(3;3)(q21;q26), typical of the syndrome of acute leukemia with high platelets. The cell line expresses CD34, CD7, TdT, and myeloid (CD13, CD14, CD33) and megakaryocyte/platelet (CD36, CD41, CD42b, CDw49b) antigens. In short-term culture, UCSD/AML1 cells proliferate in response to interleukin-3 (IL-3), IL-4, IL-6, macrophage colony-stimulating factor (M-CSF), and granulocyte-macrophage CSF (GM-CSF), but not IL-1, IL-2, IL-5, or G-CSF. In long-term culture, proliferation can be sustained by GM-CSF, IL-6, or M-CSF. When maintained in GM-CSF, a small percentage of cells form multinucleated megakaryocyte-like giant cells. Culture with GM-CSF combined with IL-6, but not with IL-6 alone, increased giant cell formation fourfold to sevenfold. IL-6 alone or in combination with GM-CSF increased expression of platelet-related antigens. In contrast, culture with phorbol ester induced formation of macrophage-like cells. UCSD/AML1 is the first human acute nonlymphocytic leukemia cell line established from a patient with an acute leukemia syndrome associated with a specific chromosome abnormality.

Acute Disease↗
PubMed1990

Terminal deletions of the long arm of chromosome 7: five new cases.

Twenty-two cases of terminal deletions of the long arm of chromosome 7 have been reported. We present 5 new cases, 3 of which were ascertained due to fetal holoprosencephaly, one due to anencephaly, and one due to multiple structural defects in a 15-year-old boy. The presence of holoprosencephaly in 3 of the 5 cases reported herein and in 2 previously reported cases suggests that this manifestation may be commonly observed in individuals with deletion 7q.

Abnormalities, Multiple↗