Peer norms moderate the association between mental health and sexual risk behaviors among young men living in Dar es Salaam, Tanzania.

BACKGROUND: Young men living in Dar es Salaam's informal settlements face environmental stressors that may expose them to multiple determinants of HIV risk including poor mental health and risky sexual behavior norms. We aimed to understand how these co-occurring risk factors not only independently affect men's condom use and sexual partner concurrency, but also how they interact to shape these risk behaviors. METHODS: Participants in the study were male members of 59 social groups known as "camps" in Dar es Salaam, Tanzania. We assessed moderation by changes in peer norms of the association between changes in symptoms of anxiety and depression and sexual risk behaviors (condom use and sexual partner concurrency) among 1113 sexually active men. Participants nominated their three closest friends in their camp and reported their perceptions of these friends' behaviors, attitudes, and encouragement of condom use and concurrency. Anxiety and depression were measured using the HSCL-25, and condom use and sexual partner concurrency were assessed through self-report. RESULTS: Perceptions of decreasing condom use among friends (descriptive norms) and decreasing encouragement of condom use were associated with lower levels of condom use. Perceptions of increasing partner concurrency and acceptability of partner concurrency (injunctive norms) among friends were associated with higher odds of concurrency. Changes in perceived condom use norms (descriptive norms and encouragement) interacted with changes in anxiety symptoms in association with condom use such that the negative relationship was amplified by norms less favorable for condom use, and attenuated by more favorable norms for condom use. CONCLUSIONS: These results provide novel evidence of the interacting effects of poor mental health and risky sexual behavior norms among a hard to reach population of marginalized young men in Dar es Salaam. Our findings provide important information for future norms-based and mental health promotion interventions targeting HIV prevention in this key population.

First-trimester trisomy screening: nuchal translucency measurement training and quality assurance to correct and unify technique.

OBJECTIVE: To describe the process of training for measuring nuchal translucency at five clinical centers in North America and to evaluate methods of quality assurance and feedback. DESIGN: Throughout a period of 18 months, the performance of sonographers in measuring fetal nuchal translucency was monitored using qualitative and quantitative methods of review. After 12 months, different approaches (written and personal feedback) were used to inform sonographers of technical aspects that needed to or could be improved. RESULTS: On initial qualitative review, discrepancies in judgment from different reviewers coincided with suboptimal magnification, failure to visualize the amniotic membrane and/or use of cross-shaped calipers. At subsequent global review, 13 (29%) images of nuchal translucency measurements were considered unacceptable. Quantitative assessment revealed that, during the first part of the study, the means from four sonographers were significantly smaller and the mean from the fifth sonographer was significantly larger than expected on the basis of findings from The Fetal Medicine Foundation (P < 0.0001). Following feedback, sonographers who underestimated nuchal translucency and who received a written report only did not change measurements overall (P = 0.9759). In contrast, those who received additional intervention showed a marked difference (P < 0.0001). CONCLUSIONS: Global qualitative review of images from one sonographer may be preferable to assessment of individual aspects of images. Results from global qualitative review correspond well with findings from quantitative analysis, indicating that the latter can be applied for ongoing audit. Observation of divergent results should prompt extensive personal feedback, rather than a written report, to prevent sonographers from settling in their own, inappropriate technique.

Validity of transabdominal sonography in the detection of a two-vessel umbilical cord.

OBJECTIVE: To determine the validity of transabdominal ultrasound in the detection of a two-vessel and a three-vessel umbilical cord. METHODS: The ultrasound and pathology databases were collated between January 1, 1999, and December 31, 2000. Only those cases with ultrasound and pathology information concerning the number of vessels in the umbilical cord were included for analysis (group 1). In addition, 27 cases with a two-vessel umbilical cord were included from the ultrasound database before January 1, 1999, for which pathologic information was also obtained (group 2). RESULTS: A total of 1295 ultrasound/pathology reports were entered from January 1, 1999, through December 31, 2000; 268 cases did not have complete information, leaving 1027 for analysis (group 1). The visualization rate of the number of vessels in the umbilical cord increased from 15 to 17 weeks' gestation (74.1-97.6%; P <.001). The visualization rate remained stable from 17.0 to 35.9 weeks' gestation, and then declined to 83.3% (P <.01). The sensitivity, specificity, positive predictive value, and negative predictive value for the diagnosis of a two-vessel umbilical cord were 85%, 99.7%, 85%, and 99.7%, respectively. CONCLUSION: The detection rate of either a two-vessel or three-vessel umbilical cord is best achieved between 17 and 36 weeks' gestation. In the majority of two-vessel umbilical cords that were called three-vessel, an appropriate transverse image of the umbilical cord was not obtained.

Inhibition of the glucose-6-phosphate transporter in oilseed rape (Brassica napus L.) plastids by acyl-CoA thioesters reduces fatty acid synthesis.

Addition of oleoyl-CoA (1 microM), or other acyl-CoA thioesters with a chain length of C(16) or greater, to oilseed rape plastids (Brassica napus L.) inhibited the rate of D-glucose 6-phosphate (Glc6P) uptake by 70% after 2 min. The IC(50) value for oleoyl-CoA inhibition of the transporter was approx. 0.2-0.3 microM. Inhibition was alleviated by the addition of acyl-CoA binding protein (ACBP) or BSA at slightly higher concentrations. Oleic acid (5-25 microM), Tween 40 (10 microM), Triton-X 100 (10 microM) and palmitoylcarnitine (5 microM) had no effect on Glc6P uptake. The uptake of [1-(14)C]Glc6P occurred in exchange for P(i), 3-phosphoglycerate or Glc6P at a typical rate of 30 nmol Glc6P/min per unit of glyceraldehyde-3-phosphate dehydrogenase (NADP(+)). The K(m(app)) of the Glc6P transporter for Glc6P was 100 microM. Neither CoA (0.3 mM) nor ATP (3 mM) inhibited Glc6P uptake, but the transporter was inhibited by 72% when ATP and CoA were added together. This inhibition was attributable to the synthesis of acyl-CoA thioesters, predominantly oleoyl-CoA and palmitoyl-CoA, by long-chain fatty acid-CoA ligase (EC 6.2.1.3) from endogenous fatty acids in the plastid preparations. Acyl-CoA thioesters did not inhibit the uptake of [2-(14)C]pyruvate or D-[1-(14)C]glucose into plastids. In vivo quantities of oleoyl-CoA and other long-chain acyl-CoA thioesters were lower than those for ACBP in early cotyledonary embryos, 0.7+/-0.2 pmol/embryo and 2.2+/-0.2 pmol/embryo respectively, but in late cotyledonary embryos quantities of long-chain acyl-CoA thioesters were greater than ACBP, 3+/-0.4 pmol/embryo and 1.9+/-0.2 pmol/embryo respectively.

Fetal compensatory renal hypertrophy with a unilateral functioning kidney.

OBJECTIVE: To evaluate the possibility of fetal compensatory renal hypertrophy with a unilateral functioning kidney. METHODS: A nomogram of renal length was established from 254 normal fetuses. Renal length was also obtained in 14 fetuses with unilateral renal agenesis and 22 fetuses with a unilateral multicystic kidney. RESULTS: Compensatory renal hypertrophy, defined as a renal length > 95th percentile for gestational age, occurred in 16 of 36 cases (44.4%). CONCLUSIONS: Compensatory renal hypertrophy is detectable in utero and may occur as early as 22 weeks' gestation.

The amniotic fluid index in normal twin pregnancies.

OBJECTIVE: We sought to investigate the amniotic fluid index for individual gestational sacs of twin pregnancies. STUDY DESIGN: Four hundred eighty-eight patients with normal diamniotic twins were examined between 14 and 40 weeks' gestation. The dividing membrane between twin fetuses was identified. An amniotic fluid index was then obtained for each gestational sac. RESULTS: The median amniotic fluid index in individual twin gestational sacs rises slowly from 14 to 16 weeks' gestation to 23 to 28 weeks' gestation and then gradually declines. The median amniotic fluid index values by gestational age for twin A and twin B are not statistically different. Although twin pregnancies have a slightly lower median amniotic fluid index value than singleton pregnancies, the difference is also not statistically significant. CONCLUSION: Individual amniotic fluid indices can be obtained in twin pregnancies, and the values are comparable with those of singleton gestations.

Reproducibility in the assessment of postmenopausal ovaries with transvaginal ultrasound.

OBJECTIVE: The goal of this study was to evaluate the interexaminer variation in the assessment of postmenopausal ovaries using transvaginal ultrasound (TVU). METHODS: One hundred eighty-eight cancer screening trial participants undergoing TVU were reassessed by a second TVU examination. RESULTS: Although first examiners tended to describe significantly larger left (P < 0.001) but smaller right (P = 0.036) ovaries, as well as fewer ovarian abnormalities, examiners agreed on the test interpretation 93% of the time (kappa = 0.846). In only two cases (1%) were the differences in interpretation such that the two examiners recommended different follow-up procedures. CONCLUSIONS: Because of the high fatality rate of ovarian cancer, early detection remains the best way to combat this devastating disease. TVU is one screening technique we are currently evaluating in a cancer screening trial. To help ensure screening test reproducibility, we have followed explcit protocols for training and certifying all TVU examiners, as well as for conducting TVU examinations. This study demonstrates that by adhering to specific training, certification, and examination protocols, TVU reproducibility is excellent. Such protocols may well serve as a standard for TVU training and examination.

Carbon supply for storage-product synthesis in developing seeds of oilseed rape.

The aim of this work was to find out how the sugars in the endosperm of oilseed rape contribute to the flux of oil synthesis. While the hexose content of the liquid endosperm decreased during development the sucrose content increased. It is important to understand the relative rates of use of the endosperm sugars for two reasons. Firstly we need to know which sugars are used, and at what stages in development, in order to understand the roles of enzymes involved in their metabolism. Secondly, changes in sugar concentration have been implicated in the regulation of expression of genes determining storage-product synthesis [see Weber, Borisjuk and Wobus (1997) Trends Plant Sci. 2, 169-174, for review]. The rate of consumption of sugar is one factor governing its concentration. We present data showing both the concentration-dependence of conversion of sugar to oil, and the in vivo concentrations of sugars; we relate these data sets to each other and discuss the effects of the intracellular pool of sucrose. Glucose, fructose and sucrose are all substrates for oil synthesis, but the rates of their use (particularly sucrose) are underestimated because of dilution by sucrose from the intracellular pool.

Transvaginal sonographic diagnosis of short-rib polydactyly dysplasia at 13 weeks' gestation.

Short-rib polydactyly dysplasia (SRP) is an autosomal recessive, lethal skeletal dysplasia. Sonographic assessment of subsequent pregnancies is, therefore, recommended. This case indicates that this diagnosis can be made in the latter part of the first trimester. A 30-year-old multigravid woman presented at 13 weeks' gestation for an ultrasound examination. She had had a termination of pregnancy for a fetus with pathologically confirmed short-rib polydactyly dysplasia, type I (Saldino-Noonan). On transvaginal sonography, a narrow chest, symmetrical micromelia, polydactyly and anasarca were present. An autopsy confirmed recurrent SRP. Short-rib polydactyly dysplasia may be diagnosed with transvaginal sonography in the first trimester.

The role of ultrasonography in the detection and management of adnexal masses during the second and third trimesters of pregnancy.

OBJECTIVE: Our purpose was to determine the effect of routine second-trimester and third-trimester ultrasonographic examinations on the prevalence of detectable and operable adnexal disease. STUDY DESIGN: The study group consisted of 7996 pregnant women between 13.0 and 42.8 weeks' gestation. The size and architectural pattern of any detectable adnexal masses were noted. RESULTS: A total of 328 of the 7996 (4.1%) women in the study group had 335 ultrasonographically detectable adnexal masses; 309 of the masses were unilocular or had a single thin septation and 26 were architecturally complex. Of the ovarian cysts 252 of 309 (81.6%) had a mean diameter < 3.0 cm; 60% of the 252 patients in this subgroup had serial ultrasonographic examinations; 43 of the unilocular cysts resolved, and 17 have persisted for up to 2 years. There is a statistically significant trend toward decreasing frequency of ovarian cysts with increasing gestational age (chi2 for linear trend; P < .00001). Eighteen of the 7996 had an exploratory laparotomy (1 operation per 444 deliveries) during pregnancy or in the postpartum period. In addition, 1 patient had a paratubal cyst excised at the time of postpartum bilateral tubal ligation. Pathologically confirmed lesions included 8 benign cystic teratomas, 3 mucinous cyst adenomas, 2 paratubal cysts, 2 corpus lutea, 1 serous cystadenoma, 1 follicular cyst, 1 endometrioma, and 1 ovarian fibroma. CONCLUSION: Ovarian cysts are found in 4.1% of second-trimester and third-trimester obstetric ultrasonographic examinations. Most ultrasonographically detectable cysts are < 3.0 cm in diameter and usually resolve. The frequency of exploratory laparotomy for adnexal disease is not significantly different from that in reports before the widespread use of obstetric ultrasonography.

The sonographic detection of early first-trimester conjoined twins.

The transvaginal transducer may be utilized to manipulate juxtaposed early first-trimester twins in order to distinguish between conjoined and separate embryos.

Vibroacoustic stimulation enhances visualization of the four-chamber cardiac view in the third trimester.

The objective of this study was to determine whether vibroacoustic stimulation would improve the visualization rate of the four-chamber cardiac view. Patients between 26 and 42 weeks' gestation were considered to be candidates for this study if the amniotic fluid index (AFI) was between 8.0 and 24.0 cm, no malformations were detected on a careful fetal anatomical survey and a four-chamber cardiac view was not obtainable. Once a four-chamber view was considered to be not obtainable due to fetal position, the patient was asked to withdraw a sealed envelope and was assigned to either the study or the control group. The 164 study patients received one to three 3-s vibroacoustic stimulations. Five minutes later a second attempt was made to visualize the four-chamber view adequately. The control group consisted of another 198 subjects in whom a four-chamber view could not be obtained. The control group did not receive vibroacoustic stimulation. A similar 5-min time interval was allowed to elapse before an attempt was made to visualize the four-chamber view. The study and control groups were similar with respect to fetal presentation, placental location, fetal weight category, biophysical profile score, gestational age, AFI and estimated fetal weight. The rate of the four-chamber view was significantly higher among fetuses receiving vibroacoustic stimulation (20.1%), in comparison to the control group (11.1%) (p = 0.019). Successful repositioning was more likely among fetuses with estimated fetal weight between 2251 and 3050 g, and at a gestational age between 33.1 and 37.0 weeks. We conclude that in a selected group of patients vibroacoustic stimulation can be used to enhance visualization of the four-chamber view.

Sonographic visualization of the ovaries throughout pregnancy.

OBJECTIVE: To determine the frequency with which one or both normal ovaries can be visualized during a routine obstetric ultrasound examination. METHODS: The population consisted of 5617 pregnant women at 5.0-39.9 weeks' gestation, studied cross-sectionally. The sonographic visualization rate for one or both normal ovaries, as well as their position above or below the level of the umbilicus, was recorded for one examination in each patient. RESULTS: The study population was divided into three groups according to gestational age: first trimester, 5.0-12.9 weeks; second trimester, 13.0-26.9 weeks; and third trimester, 27.0-39.9 weeks. There were 829, 3195, and 1593 women in the first, second, and third trimesters, respectively. Most women were examined transvaginally in the first trimester; transabdominal sonography was used in the second and third trimesters. The ability to visualize one or both ovaries declined significantly (P < .05) from the first trimester to the second, as well as from the second trimester to the third (P < .001). The percentage of ovaries that were visualized above the umbilicus increased from 2.4% in the first trimester to 10.1% in the second trimester (P < .001), and to 21.7% in the third trimester (P < .001). CONCLUSION: As gestational age advances, there is a significant reduction in the ultrasound visualization rate of normal ovaries. This investigation provides normative data for ovarian visualization throughout pregnancy that may be helpful in establishing ultrasound laboratory standards.

The effect of amniotic sheet orientation on subsequent maternal and fetal complications.

The purpose of this investigation was two-fold, first, to determine the incidence of amniotic sheets in our obstetric population; and, second, to elucidate the maternal and fetal complications associated with this particular finding. In this retrospective study, we searched the computerized records of the ultrasound department for the presence of amniotic sheets in singleton pregnancies from 1 March 1991 to 17 September 1993. Sonographic criteria for an amniotic sheet included the findings that (1) a reflective membrane attached to the placenta at one end or the other, with measurable thickness, was identified traversing the amniotic fluid; and (2) the fetus was not attached to the membrane, and fetal ability to move without restriction was ascertained. An amniotic sheet was identified in 79 of 17,553 examinations (0.45%) performed between 12 and 28 weeks' gestation. Two subsets of amniotic sheets were identified: perpendicular and not perpendicular. The sheets in the first subset were orientated perpendicular to the placental surface and were more likely to be associated with an abnormal presentation at delivery (p < 0.001) and a history of pelvic inflammatory disease, but not with a history of prior Cesarean section, or previous dilatation and curettage. The second subset of amniotic sheets were non-perpendicular, either oblique or parallel, in orientation to the placental surface and were associated with fewer maternal complications. Of the study group, 40.7% had a history of vaginal bleeding. The incidence of vaginal bleeding was not significantly different between those patients with perpendicular or those with non-perpendicular amniotic sheets. We conclude that perpendicular, in contrast to non-perpendicular, amniotic sheets are more commonly associated with breech presentation at term and a past history of pelvic inflammatory disease.

Sonographic determination of first trimester twin chorionicity and amnionicity.

OBJECTIVE: To determine the reliability of first trimester sonography in the detection of twin chorionicity and amnionicity. MATERIALS AND METHODS: Sets of twins (179) were evaluated sonographically in the first trimester. Chorionicity was determined by identifying the number of gestational sacs. The presence or absence of an amnion about each embryo/fetus was also recorded. The placentas for each case were evaluated to determine chorionicity and amnionicity. RESULTS: Of the 179 twin pairs, 158 were dichorionic/diamniotic; 19 were monochorionic/diamniotic, and two pairs were monochorionic/monoamniotic. Chorionicity and amnionicity were correctly determined in each case. CONCLUSION: The chorionicity of twin pregnancies can be determined from the time that the gestational sacs are visualized within the uterus. Transvaginal sonography can reliably determine the amnionicity of monochorionic twin pregnancies after 7 weeks, menstrual age.