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Biomedical subjects

M Durbin

Publications and source records attributed to M Durbin.

13 recordsLinked to original sources
PubMed2006

A pilot study of children's exposure to CCA-treated wood from playground equipment.

Arsenic from chromated copper arsenate (CCA)-treated wood, widely used in playgrounds and other outdoor equipment, can persist as surface residues on wood. This raises concerns about possible health risks associated with children playing on CCA-treated playgrounds. In a Pilot Study, 11 children (13-71 months) in homes with and without CCA-treated playgrounds were evaluated with post-exposure hand rinses and urine for total arsenic. Samples of wood, soil, and mulch, as well as synthetic wipes, were sampled for total arsenic. In non-CCA-treated playgrounds vs. CCA-treated playgrounds, respectively, wood arsenic was <2.0 mg/kg vs. mean arsenic 2370 mg/kg (range 1440-3270 mg/kg); soil arsenic was <3.0 mg/kg vs. mean arsenic of 19 mg/kg (range 4.0-42 mg/kg); mulch arsenic at one non-CCA-treated playground was 0.4 mg/kg vs. two CCA-treated playgrounds of 0.6 and 69 mg/kg. The arsenic removed using a synthetic wipe at non-CCA-treated playgrounds was <0.5 microg, while mean arsenic from CCA-treated wood was 117 microg (range 1.0-313). The arsenic mass from hand rinses for children who played at non-CCA-treated playgrounds was <0.2 microg, while mean arsenic mass was 0.6 microg (range <0.2-1.9) at CCA-treated playgrounds. Mean urinary total arsenic levels were 13.6 pg/ml (range 7.2-23.1 pg/ml) for all children evaluated, but there was no association between access to CCA-playgrounds and urinary arsenic levels. Arsenic speciation was not performed. This preliminary Pilot Study of CCA-treated wood playgrounds observed dislodgeable arsenic on 11 children's hands after brief periods of play exposure. Future efforts should increase the number of children and the play exposure periods, and incorporate speciation in order to discriminate between various sources of arsenic.

Arsenates↗
PubMed2005

"Ultra-light" patient-controlled epidural analgesia during labor: effects of varying regimens on analgesia and physician workload.

BACKGROUND: Patient-controlled epidural analgesia (PCEA) offers many advantages over continuous epidural infusions for maintenance of labor analgesia. Some of these benefits may depend on the PCEA settings. This study evaluated several regimens for "ultra-light" (0.125%) PCEA with basal continuous infusion (CI) in labor with goals of minimizing physician interventions while providing good analgesia. METHODS: Two hundred and twenty ASA I-II women receiving epidural analgesia during active labor (cervical dilation <5 cm) were randomly assigned in a double-blind manner to four treatment groups (n=30 in each). Analgesia was maintained with a PCEA/CI pump using bupivacaine 0.0625% + sufentanil 0.35 microg/mL. PCEA settings were: group A: CI 10 mL/h, PCEA bolus 6 mL, 8-min lockout; group B: CI 10 mL/h, PCEA bolus 12 mL, 16-min lockout; group C: CI 15 mL/h, PCEA bolus 6 mL, 8-min lockout; group D: CI 15 mL/h, PCEA bolus 12 mL, 16-min lockout. RESULTS: In groups A, B, C and D, 76, 77, 75 and 85% of parturients respectively, required no physician rescue boluses. Pain scores were low and maternal satisfaction was high in all groups, with minimal differences among them. Spontaneous vaginal delivery occurred in 78% of patients overall, instrumental (forceps or vacuum) delivery in 10% and cesarean section in 12%. CONCLUSIONS: These ultra-light PCEA regimens provided excellent analgesia with minimal physician workload and a high spontaneous delivery rate. Use of moderate to high-volume, ultra-light PCEA/CI techniques should facilitate provision of labor analgesia in busy obstetric units.

Adult↗
PubMed1998

Ewing's sarcoma masquerading as osteomyelitis.

Ewing's sarcoma in the infant and young child is rare, highly malignant, and can be difficult to identify. An erroneous diagnosis of osteomyelitis may be considered first because the presentation may be similar to that of Ewing's sarcoma, and routine laboratory evaluation may not distinguish between these entities. Two such cases are presented, one involving the tibia in a 16-month-old child and another a finger phalanx in a 7-month-old child. In both cases the correct diagnosis of Ewing's sarcoma was delayed because of initial misdiagnosis of osteomyelitis. This diagnostic dilemma is summarized, and the literature reviewed. Special attention is given to recent advances in histochemistry and cytogenetics that assist in tumor identification. The conclusion highlights areas of remaining controversies for which additional study may facilitate distinction between osteomyelitis and Ewing's sarcoma.

Bone Neoplasms↗
PubMed1995

Change in junior high school students' AIDS-related knowledge, misconceptions, attitudes, and HIV-preventive behaviors: effects of a school-based intervention.

A school-based AIDS-prevention program for junior high school students was developed and implemented in an inner-city area in northern California that serves predominantly African-American and Asian students. The curriculum, taught by science teachers, consisted of twelve classroom sessions using both didactic and interactive exercises covering sex education, HIV biology, drug use, decision-making and refusal skills, and public response to AIDS and community resources. Changes from baseline of self-reported responses to questions on pre- and posttests concerning AIDS knowledge and misconceptions, tolerance toward persons with AIDS, and high-risk behaviors were compared between intervention and control schools. Students in the intervention schools had a significant increase in AIDS knowledge (p < .0001) and became more tolerant of people with AIDS (p < .001) compared with students in the control school. Changes in high risk behavior could not be detected, perhaps due to the small number of sexually active students (24% of the sample). Students who increased their AIDS knowledge (p < .0001) as a result of the intervention became more tolerant of people with AIDS. A school-based HIV-prevention curriculum, taught by trained classroom teachers, can modify middle adolescents' HIV-related knowledge about the casual transmission of HIV, and their attitudes toward persons with AIDS.

Adolescent↗
PubMed1993

Factors associated with multiple sex partners among junior high school students.

Twenty-one percent of a sample of inner-city junior high school students were found to be sexually active (n = 403). Only 31% of them reported a single lifetime sexual partner, 25% reported two partners, and 43% reported three or more partners. Logistic regression analysis evaluated the influence of demographic, psychosocial, and behavioral factors on the adolescents' lifetime number of sex partners. Respondents whose sexual debut occurred before age 13 years were nine times more likely to report three or more sex partners compared with those whose first sexual intercourse was at age 15 or 16 years, blacks were four times more likely than non-Hispanic whites to report three or more sex partners; and males were four times as likely as females to report this number of sexual partners. Factors not independently associated with the number of sex partners included: age, Asian or Hispanic ethnicity, human immunodeficiency virus (HIV) knowledge, self-efficacy (belief that one can protect oneself from the virus), condom use, and alcohol and drug use. We conclude that a significant proportion of school-based middle adolescents are sexually active and that most of these are at risk for contracting HIV because of behaviors such as having multiple sexual partners. Topics often stressed in school-based HIV education, such as factual knowledge about HIV, avoiding drugs and alcohol, and condom use are not associated with adolescents' choice about their number of sex partners. Intervention programs will have to identify and then target each specific HIV risk behavior and its motivations in order to reduce adolescents' risks of contracting and transmitting the disease.

Adolescent↗
PubMed1992

Determinants of condom use among junior high school students in a minority, inner-city school district.

Condoms reduce the risk of human immunodeficiency virus (HIV) transmission; however, their use among adolescents has been inconsistent. Little is known about factors which motivate consistent condom use, particularly among younger adolescents. In a study designed to identify such factors, 1899 inner-city junior high school students were surveyed. In June 1988, students completed an anonymous self-report questionnaire assessing HIV-related knowledge, attitudes, and behaviors. Among sexually active students (N = 403), logistic regression analysis evaluated the influence of demographic, psychosocial, and behavioral factors on frequency of condom use. Respondents who believe condoms are effective in preventing HIV transmission were 2.2 times more likely to report using condoms consistently during sexual intercourse; those with low perceived costs associated with condom use were 1.9 times more likely to be consistent users. Number of lifetime sexual partners was inversely related to frequency of condom use. Respondents with a history of three or more sex partners were half as likely to use condoms consistently. Factors not associated with consistent condom use include age, age at sexual debut, ethnicity, HIV knowledge, perceived efficacy to avoid HIV infection, and alcohol and drug use. School- and community-based HIV prevention programs will have to go beyond the didactic transfer of factual information and include more interactive teaching strategies to improve adolescents' attitudes toward condoms are self-efficacy to increase condom use and to counter negative peer influences and adolescents' perceptions of invulnerability. Physicians are an underutilized source of HIV prevention information. They have an important role in counseling adolescents about effective HIV-prevention methods and dispelling misperceptions which hinder consistent condom use.

Acquired Immunodeficiency Syndrome↗
PubMed1991

AIDS knowledge, attitudes, and behavior among inner city, junior high school students.

To gain information about AIDS knowledge, attitudes, and behavior of junior high school students, 1,967 students in three junior high schools in an inner city school district were surveyed. Ages of the participants ranged from 11-16 years, and 48% were male. Ethnically, 33% were Asian, 31% African-American, 24% Latino, and 5% white. African-American students had greater AIDS general knowledge than Asians and similar general knowledge to Latinos and whites. Most students wanted to be taught about AIDS in school. Misconceptions about casual contagion of AIDS were common. Students with these misconceptions were more likely to believe that students with AIDS should not be allowed to attend school. A high proportion of students had engaged in high-risk behavior including sexual intercourse, drinking alcoholic beverages, and using street drugs. More boys than girls reported each of these activities. Of individuals having had sexual intercourse, a positive association was found between the belief that condoms are effective in preventing HIV infection and use of condoms. These findings support the possibility that improving knowledge about HIV transmission would result in more tolerance toward students with HIV infection and would result in less high-risk behavior.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Chloroplast DNA sequence from a miocene Magnolia species.

DNA has been successfully extracted from several samples of preserved tissue, the oldest so far reported originating from a 13,000-year-old ground sloth. Both severe damage to the preserved DNA, primarily due to oxidation of the pyrimidines, has prevented the acquisition of sequence data from ancient samples except in a few cases. We report here the extraction of DNA from fossil leaf samples from the Miocene Clarkia deposit (17-20 Myr old), the amplification of an 820-base pair (bp) DNA fragment from the chloroplast gene rbcL from a fossil of the genus Magnolia, and its subsequent sequencing. The sequence was verified by comparison with published and unpublished rbcL sequences. These results extend our ability to analyse ancient DNA and may open new avenues into problems in palaeobotany, biogeography, and in the calibration of mutation rates.

Base Sequence↗
PubMed1990

rbcL sequence divergence and phylogenetic relationships in Saxifragaceae sensu lato.

Phylogenetic relationships are often poorly understood at higher taxonomic levels (family and above) despite intensive morphological analysis. An excellent example is Saxifragaceae sensu lato, which represents one of the major phylogenetic problems in angiosperms at higher taxonomic levels. As originally defined, the family is a heterogeneous assemblage of herbaceous and woody taxa comprising 15 subfamilies. Although more recent classifications fundamentally modified this scheme, little agreement exists regarding the circumscription, taxonomic rank, or relationships of these subfamilies. The recurrent discrepancies in taxonomic treatments of the Saxifragaceae prompted an investigation of the power of chloroplast gene sequences to resolve phylogenetic relationships within this family and between the Saxifragaceae and other major plant lineages. Sequence data from the gene rbcL (ribulose-1,5-bisphosphate carboxylase, large subunit) reveal that (i) Saxifragaceae sensu lato is at least paraphyletic, and probably polyphyletic, (ii) the genera Parnassia and Brexia are only distantly related to other members of Saxifragaceae, and (iii) representatives of the Solanaceae (subclass Asteridae) appear more closely related to Saxifragaceae (subclass Rosidase) than traditionally maintained. These data illustrate the value of chloroplast gene sequence data in resolving genetic, and hence phylogenetic, relationships among members of the most taxonomically complex groups.

Base Sequence↗
PubMed1988

Changes in Two Forms of Membrane-Associated Cellulase during Ethylene-Induced Abscission.

Only one form of membrane-associated cellulase was found previously in the lower petiolar pulvinus of Phaseolus vulgaris (cv Red Kidney). The cellulase has an isoelectric point (pI) of 4.5 (DE Koehler, LN Lewis 1979 Plant Physiol 63: 677-679). This enzyme was detected in abscission zones collected before the onset of abscission (control tissue), and was thought to represent a pre-secretory form of another cellulase, the abscission cellulase, which has a basic pI and is secreted during abscission. We now show that this acidic, membrane-associated cellulase is a glycoprotein, tightly bound to the membrane, with maximum activity at pH 5.1, and that it is not immunologically related to the abscission cellulase. Furthermore, when bean explants are induced to abscise with ethylene, the activity of the acidic cellulase declines rapidly to 50% of control levels in the first day. When abscission is fully developed, the membranes contain a basic form of cellulase with a pI of 8.0 to 9.0 and only trace levels of the acidic cellulase. The basic form is not a high mannose glycoprotein; it has maximum activity in a broad pH range (4.0-8.0) and is antigenically related to the abscission cellulase, which is induced during abscission and transported to the cell wall. Antibody raised against the abscission cellulase recognized two proteins in a crude membrane fraction from abscising tissue. One of those proteins comigrated with the abscission cellulase, and the other was 1 to 2 kilodaltons larger. Thus, during abscission, the acidic membrane-associated cellulase rapidly declines before the appearance of the abscission cellulase. We conclude that there is no conversion from the acidic cellulase to the basic cellulase and suggest that the acidic and basic cellulase isoenzymes are proteins derived from two different genes.

Journal Article↗
PubMed1988

Bone marrow transplantation: economic, ethical, and social issues.

Bone marrow transplantation is a useful model for the controversies surrounding medical technologies that involve high cost, mortality, and complications. This essay first delineates the economic circumstances of bone marrow transplantation, comparing it with other organ transplantations. Although children represent a significant proportion of bone marrow transplantation patients, little research has focused on the economic impact for this population. Next, the financial, social, and ethical motivations and controversies that surround bone marrow transplantation are explored, along with current allocation mechanisms. Finally, recommendations are offered for guiding discussions regarding the appropriate use of bone marrow transplantation. In making transplantation decisions, physicians must consider the costs and benefits of bone marrow transplantation for each patient. Such analyses, whether based on medical or socioeconomic criteria, are insufficient to resolve the fundamental cultural dilemmas posed by this procedure and other expensive medical technologies, however. The goal is to foster broader discussion of these issues to achieve more candid decisions in allocating resources among competing health priorities.

Aborted Fetus↗