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Biomedical subjects

D A McLean

Publications and source records attributed to D A McLean.

At least 19 recordsLinked to original sources
PubMed2001

Outcome of prenatally diagnosed mild unilateral cerebral ventriculomegaly.

The objective of this study was to determine the frequency of prenatally diagnosed unilateral cerebral ventriculomegaly and also to assess neonatal outcome in infants with this prenatal diagnosis. A computerized ultrasonography database identified fetuses with isolated and nonisolated unilateral cerebral ventriculomegaly from October 1994 to June 1999. The Denver II Developmental Screening Test was used to assess developmental skills. Unilateral cerebral ventriculomegaly was diagnosed in 15 of 21,172 (1 per 1,411) pregnancies. The width of the enlarged lateral ventricle ranged from 1.0 to 1.9 cm. In 10 (67%) of 15 cases unilateral cerebral ventriculomegaly was an isolated finding. Eight of the 14 infants who were born at 36 weeks' gestation or later had postnatal cranial imaging, and ventricular asymmetry was confirmed in 5 (63%). One infant with an arachnoid cyst and cerebral palsy died at 2 years of age. The remaining 11 infants in whom developmental milestones were assessed had age-appropriate skills. Unilateral fetal ventriculomegaly is usually an isolated finding and when isolated has little measurable effect on developmental outcome.

Cerebral Ventricles↗
PubMed2001

Fetal intracardiac echogenic foci: visualization depends on the orientation of the 4-chamber view.

OBJECTIVE: To compare the frequency of visualization of echogenic intracardiac foci in different cardiac views. METHODS: Women having ultrasonographic examinations between October 1997 and July 1998 were prospectively evaluated if a fetal echogenic intracardiac focus was seen in either ventricle. RESULTS: Echogenic intracardiac foci were seen in 89 fetuses in whom both the apical and lateral 4-chamber heart views were obtained. Eight-six fetuses (97%) had a single focus (83 in the left ventricle and 3 in the right ventricle), and 3 (3%) had 2 foci. Echogenic intracardiac foci were seen in the apical 4-chamber view in 89 (100%) and in the lateral 4-chamber view in only 26 (29%; P = .001). CONCLUSIONS: Echogenic intracardiac foci are not easily seen in the lateral 4-chamber view. Studies that suggest an increased risk of aneuploidy when echogenic foci are seen should specify the orientation of the 4-chamber view used.

Adult↗
PubMed2000

Foot length in fetuses with abnormal growth.

Sonographic fetal foot length is highly predictive of gestational age. In order to assess the reliability of this parameter in predicting gestational age in cases of abnormal fetal growth, we examined fetal foot length in small- and large-for-gestational-age fetuses. A nomogram of foot length versus gestational age between 15 and 37 weeks was constructed using cross-sectional data obtained from 5372 singleton fetuses. Fetal foot lengths for small-for-gestational-age fetuses (estimated fetal weight below the 10th percentile) and large-for-gestational-age fetuses (above the >90th percentile) fetuses were plotted against the foot length nomogram in order to determine the number of small-for-gestational-age fetuses and large-for-gestational-age fetuses with foot lengths below the 10th and above the 90th percentiles, respectively. Of the 586 small-for-gestational-age fetuses, 355 (60.6%) had foot lengths below the 10th percentile on the nomogram. When foot lengths from large-for-gestational-age fetuses were plotted on the foot length nomogram, 29.4% (219 of 744) had measurements above the 90th percentile. Fetal foot length can be influenced by growth restriction as well as states of accelerated fetal growth. Our findings imply that there are limitations to the use of fetal foot length for gestational age assessment, particularly in fetuses with growth abnormalities.

Female↗
PubMed1997

The natural history of a positive response to transfundal pressure in women at risk for cervical incompetence.

OBJECTIVE: Our purpose was to observe the evolution of the endocervical canal length in women at risk for cervical incompetence after a positive response to transfundal pressure. STUDY DESIGN: Ten women at risk for cervical incompetence had a midtrimester cervical evaluation with transvaginal ultrasonography and transfundal pressure. With a transvaginal probe, the endocervical canal length was first measured. Transfundal pressure was then applied and the endocervical canal length was remeasured. All patients had a positive response to transfundal pressure as defined by a decrease in endocervical canal length after application of transfundal pressure. At the initial evaluation the digital examination of the cervix had revealed a closed and long cervix in all 10 cases. In 9 of the 10 patients repeat examinations were performed until the endocervical canal length progressively shortened to <10 mm or the digital examination revealed a dilated cervix. The endocervical canal lengths after application of transfundal pressure from the first and last examination were compared. One patient was lost to follow-up, but the obstetric outcome was available. RESULTS: The median time interval between the first and final examination was 7 (2 to 20) days in 9 of the patients. The median (range) gestational age at the first and final examination was 19.0 (15 to 22) weeks (n = 10) and 20.5 (18 to 24) weeks (n = 9), respectively. There was significant shortening of the endocervical canal length from the first to the last examination; 12.2 (4 to 20) mm (n = 10) versus 0.0 (0 to 9.5) mm (n = 9), p = 0.008. Six patients had membranes at the external cervical os before application of transfundal pressure at the last examination. The one patient lost to ultrasonographic follow-up had a pregnancy loss at 23 weeks of gestation, 6 weeks after a positive response to transfundal pressure. CONCLUSION: In patients at risk for cervical incompetence, shortening of the endocervical canal length in response to transfundal pressure requires treatment with a cervical cerclage because it is associated with progressive cervical changes over 1 to 3 weeks.

Cervix Uteri↗
PubMed1997

Second-trimester ultrasound markers for detection of trisomy 21: which markers are best?

OBJECTIVE: To investigate which second-trimester ultrasound markers for aneuploidy are the most diagnostically efficient in detecting fetal trisomy 21. METHODS: All second-trimester genetic sonograms performed since November 1, 1992 for women at increased risk for fetal trisomy 21 were analyzed retrospectively. Statistical analysis included descriptive statistics, the test of proportions, and univariate and multivariable logistic regression analysis using trisomy 21 as the dependent variable and ten aneuploidy ultrasound markers as independent variables. RESULTS: There were 581 normal fetuses, 23 with trisomy 21 and four with other chromosomal abnormalities. When one or more abnormal ultrasound markers were present, the sensitivity and false-positive rate for trisomy 21 were 87% and 13.4%, respectively. After adjusting for confounders, multivariate logistic regression analysis showed the best combination of ultrasound markers for detecting trisomy 21 to be nuchal fold thickening (relative risk [RR] 85.5; 95% confidence interval [CI] 20.4, 357.7), pyelectasis (RR 25.2; 95% CI 6.7, 95.0), and short humerus (RR 20.4; 95% CI 4.5, 92.1). The model combining these three ultrasound markers yielded a sensitivity of 87% and a false-positive rate of 6.7%. CONCLUSION: By using only three ultrasound markers (combination of nuchal fold thickening, pyelectasis, and short humerus) the false-positive rate is decreased from 13.4% to 6.7% without any compromise in the sensitivity (87%). The clinical usefulness of evaluating the various second-trimester ultrasound markers needs to be evaluated in prospective studies.

Confidence Intervals↗
PubMed1997

Choice of second-trimester genetic sonogram for detection of trisomy 21.

OBJECTIVE: To determine the utilization rate of second-trimester genetic sonogram and its role in influencing the decision for amniocentesis in women at increased risk for fetal trisomy 21. METHODS: From November 1, 1993, to December 31, 1996, a second-trimester genetic sonogram or only genetic amniocentesis (as a first choice) were offered to pregnant women referred to our institution who were at increased risk for fetal trisomy 21. RESULTS: During the study period, 2089 women were referred to our unit for genetic prenatal diagnosis; of these, 1426 (68%) chose only genetic amniocentesis, and 663 (32%) chose a genetic sonogram as their first option. The yearly utilization rates of genetic sonogram were two of 477 or 0.4% for 1993, 82 of 495 or 16.6% for 1994, 251 of 523 or 48.0% for 1995, and 328 of 594 or 55.2% for 1996. Adjusting for potential confounders, multivariable logistic regression analysis showed that the most important factors associated with the women's decision to undergo genetic amniocentesis were three or more ultrasound markers present (relative risk [RR] 189.5, 95% confidence interval [CI] 37.1, 980.0), two ultrasound markers present (RR 47.2, 95% CI 9.8, 267.8), one ultrasound marker present (RR 12.7, 95% CI 5.5, 29.7), and abnormal serum biochemistry (RR 3.0, 95% CI 1.0, 8.9). CONCLUSION: The increasing utilization trend, in conjunction with the fact that an abnormal sonogram was the most influential factor in women's decision to undergo genetic amniocentesis, suggests that genetic sonogram services for detection of trisomy 21 should be added to the armamentarium of all prenatal diagnostic centers.

Adult↗
PubMed1996

Analysis of repeat cesarean delivery indications: implications of heterogeneity.

OBJECTIVE: Our purpose was to describe the relative contributions and characteristics of various subgroups of patients to the overall repeat cesarean delivery rate and to determine modifiable practice patterns that might lead to fewer repeat cesarean deliveries. STUDY DESIGN: Hospital records of all women with a previous cesarean section who were delivered between Jan. 1 and June 30, 1994, at St. Peter's Medical Center in New Brunswick, New Jersey, were reviewed. Four groups were identified: (1) elective repeat cesarean, (2) "indicated" repeat cesarean, (3) failed vaginal birth after cesarean, and (4) successful vaginal birth after cesarean. Descriptive and outcome data were collected. RESULTS: There were 406 patients, 376 of whom had complete records available for review. Of these, 235 had a repeat cesarean delivery because of the following reasons: elective (107, 45%), "indicated" (56, 24%), and failed vaginal birth after cesarean (72, 31%). The remaining 141 patients had a vaginal birth after cesarean. Patients with private or health maintenance organization insurance were nearly seven times more likely to have a repeat cesarean delivery as an elective procedure as compared with Medicaid or self-pay patients (odds ratio 6.88, 95% confidence interval 2.33 to 20.38). The failed vaginal birth after cesarean group was characterized by more frequent inductions of labor, less use of amniotomy, and very early epidural placement. CONCLUSIONS: Examination of patient characteristics is required to identify population-specific strategies to reduce repeat cesarean delivery rates. Modifiable practice patterns exist that may lead to interventions to reduce repeat cesarean delivery rates.

Adult↗
PubMed1995

Mutations in aurora prevent centrosome separation leading to the formation of monopolar spindles.

We show that female sterile mutations of aurora (aur) are allelic to mutations in the lethal complementation group ck10. This lies in a cytogenetic interval, 87A7-A9, that contains eight transcription units. A 250 bp region upstream of both aur and a divergent transcription unit corresponds to the site of a specific chromatin structure (scs') previously proposed to be a barrier to insulate enhancers of the major hsp70 gene at 87A7. Syncytial embryos derived from aur mothers display closely paired centrosomes at inappropriate mitotic stages and develop interconnected spindles in which the poles are shared. Amorphic alleles result in pupal lethality and in mitotic arrest in which condensed chromosomes are arranged on circular monopolar spindles. The size of the single centrosomal body in these circular figures suggests that loss of function of the serine-threonine protein kinase encoded by aur leads to a failure of the centrosomes to separate and form a bipolar spindle.

Alleles↗
PubMed1994

A model for HIV risk reduction and prevention among African American college students.

Training African American student leaders as peer educator-mentors to reach African American students in the traditional workshop setting as well as in informal, one-to-one occasions is an effective method of managing students' risks of human immunodeficiency virus (HIV) infection. The Ujima project, developed and implemented by Syracuse University Health Services, trained educator-mentors to provide first-year African American students with correct information about HIV risk reduction and how to build life skills associated with prevention that enhance self-esteem and provide ongoing social support on formal and informal occasions in a culturally sensitive manner. These strategies were successful in changing knowledge, attitudes, and behaviors necessary for HIV prevention among African American college students.

Black or African American↗
PubMed1994

Incarceration of the gravid uterus.

Retroversion of the first trimester uterus occurs in 6 to 19 per cent of all pregnancies and usually does not cause problems. If the uterus remains retroverted as the pregnancy advances, it may become wedged into the pelvic cavity. This complication is referred to as uterine incarceration which can lead to spontaneous abortion, preterm labor, uterine dystocia, and inadvertent incision into the cervix or the bladder during cesarean section in cases of unrecognized incarceration. Seven cases of uterine incarceration are presented with a detailed review including clinical signs and symptoms, physical findings, ultrasound findings, and treatment modalities for each stage of pregnancy. Moreover, we present a new method of treatment for second trimester uterine incarceration.

Adult↗
PubMed1992

Transverse cerebellar diameter measurements in twin pregnancies and the effect of intrauterine growth retardation.

OBJECTIVES: Transverse cerebellar diameter measurements have been established for singleton but not twin pregnancies. In singleton pregnancies controversy exists on whether cerebellar growth is affected by intrauterine growth retardation. We undertook this retrospective study in twin pregnancies to establish a nomogram for the transverse cerebellar diameter in twins and to assess the effect of growth retardation on this measurement. STUDY DESIGN: A retrospective review was performed on 171 patients with twin pregnancies with reliable dating from 15 to 36 weeks' gestation who had been referred to our antenatal evaluation unit for routine ultrasonographic examination. Of the 342 fetuses, 322 were available for analysis and establishment of a nomogram for the transverse cerebellar diameter. Twenty-four twin, growth-retarded fetuses were analyzed separately. RESULTS: The transverse cerebellar diameter increased linearly with gestational age (r = 0.94, p < 0.001). Fifteen (63%) of the growth-retarded fetuses had a transverse cerebellar diameter of < or = 5th percentile for gestational age. CONCLUSION: We suggest that intrauterine growth retardation may affect cerebellar growth in twins.

Cerebellum↗
PubMed1992

Analysis of the physical demands of international rugby union.

The aim of this study was to investigate the physical demands of international rugby union. Five games in the 1989-90 Five Nations Championship were analysed using video-recordings of live television transmissions. When the ball was in open play, the average running pace of players central to the action ranged from 5 to 8 m s-1. This together with scrum, lineout, ruck and maul was classified as high-intensity exercise. The density of work was measured by timing the work:rest ratios (W:RRs) throughout each game. The mean duration of the work periods was 19 s and the most frequent W:RRs were in the range of 1:1 to 1:1.9. On average, a scrum, lineout, ruck or maul occurred every 33 s. The ball was in play for an average of 29 min during a scheduled time of play of 80 min. To complement the time-motion analysis, blood samples were taken from six players throughout a first-class game. The highest measured blood lactate (BLa) concentrations for each individual ranged from 5.8 to 9.8 mM. Running speed, duration, BLa levels, physical confrontation and, most particularly, the density of work as illustrated by the W:RRs indicate that the game places greater demands on anaerobic glycolysis than previously reported. This has implications for the physical conditioning of rugby union players.

Anaerobiosis↗
PubMed1991

The relationship between fetal biophysical assessment, umbilical artery velocimetry, and fetal acidosis.

In a prospective study of 62 patients undergoing cesarean delivery before the onset of labor, fetal biophysical assessment and umbilical artery systolic-diastolic ratios (S/Ds) were performed within 3 hours of delivery. There was a significant relationship between the fetal biophysical profile score and cord arterial as well as cord venous pH. However, there was no identifiable relationship between S/D and cord arterial or venous pH. The efficacies of the biophysical components alone (nonstress test [NST] and fetal biophysical profile) and in combination with S/D to predict fetal acidosis were determined. The NST had the best sensitivity (100%) and negative predictive value (100%). The fetal biophysical profile had the best specificity (91%), positive predictive value (62%), and overall efficiency (90%). The S/D had the lowest sensitivity (66%), specificity (42%), positive predictive value (16%), negative predictive value (88%), and overall efficiency (45%). The addition of S/D to the NST or fetal biophysical profile did not improve diagnostic accuracy. These data suggest that the NST should be used as a primary test for the antepartum detection of fetal acidosis, whereas the fetal biophysical profile is a reasonable adjunct test. The umbilical artery S/D, as determined by continuous-wave Doppler velocimetry, has no value as a primary method or an adjunct in the antepartum detection of fetal acidosis.

Acidosis↗
PubMed1990

Improved fragile site detection with trimethoprim.

The effect of trimethoprim, an inhibitor of dihydrofolate reductase, in demonstrating the presence of fragile sites on human chromosomes was investigated. Lymphocyte cultures with 20 mg/l trimethoprim added at the onset of incubation gave consistently higher frequencies of fragile sites than the other culture regimes tested.

Chromosome Fragile Sites↗
PubMed1990

Role of the team physiotherapist in rugby union football.

The team physiotherapist plays an important role in rugby union football. Traditionally, this is seen as injury care and rehabilitation, but increasingly the role focuses on injury prevention. The author discusses these aspects with reference to statistics from recent Scottish international tours.

Adult↗
PubMed1990

Obstetrical applications of computer technology.

Computer technology and the use of personal computers in obstetrics, particularly antepartum, and intrapartum fetal evaluation, are discussed. The future direction of computer technology in fetal assessment is also addressed.

Computer Communication Networks↗