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Biomedical subjects

D Levine

Publications and source records attributed to D Levine.

At least 91 records · Page 5Linked to original sources
PubMed1996

Fetal anatomy revealed with fast MR sequences.

Although all the imaging studies in this pictorial essay were done for maternal rather than fetal indications, fetal anatomy was well visualized. However, when scans are undertaken for fetal indications, fetal motion in between scout views and imaging sequences may make specific image planes difficult to obtain. Of the different techniques described in this review, we preferred the HASTE technique and use it almost exclusively for scanning pregnant patients. The T2-weighting is ideal for delineating fetal organs. Also, the HASTE technique allows images to be obtained in 430 msec, limiting artifacts arising from maternal and fetal motion. MR imaging should play a more important role in evaluating equivocal sonographic cases as fast scanning techniques are more widely used. Obstetric MR imaging no longer will be limited by fetal motion artifacts. When complex anatomy requires definition in a complicated pregnant patient, MR imaging should be considered as a useful adjunct to sonography.

Female↗
PubMed1996

The effects of pelvic movement on lumbar lordosis in the standing position.

The purpose of this study was to investigate whether the maneuver of altering the angle of pelvic tilt when standing is effective in changing the angle of lumbar lordosis. The importance of the study was to establish a scientific basis for a common clinical assumption. Pelvic tilt and lumbar lordosis were measured during three conditions: with subjects in a normal standing posture, with subjects assuming a maximal anterior pelvic tilt posture, and with subject assuming a maximal posterior pelvic tilt posture. Measurements of pelvic tilt and lumbar lordosis were obtained using a television/computer system that obtained the three-dimensional coordinates of markers on the pelvis and spine at 20-msec intervals. Each measurement was made three times, and all were found to be reliable, with intraclass correlation coefficients (3,1) ranging from 0.78 to 0.95 (p < 0.001). Adopting a maximal anterior pelvic tilt changed the pelvic attitude relative to the horizontal by an average fo 11.4 degrees (p < 0.001) and increased the lumbar lordosis by an average of 10.8 degrees (p < 0.001). Adopting a maximal posterior pelvic tilt changed the pelvic attitude by an average of 8.7 degrees (p < 0.001) and decreased the lumbar lordosis by an average of 9.0 degrees (p < 0.001). The results of this study demonstrate that altering the pelvic tilt significantly changes the angle of lumbar lordosis. This lends support to the use of pelvic tilting exercises to increase or decrease the degree of lumbar lordosis, at least for the duration of the exercise.

Adult↗
PubMed1996

Dolichocephaly and oligohydramnios in preterm premature rupture of the membranes.

This study evaluates the association between dolichocephaly and fetal outcome after preterm premature rupture of membranes. Dolichocephaly was more common in preterm fetuses in the breech presentation than those in the cephalic presentation and was more common in fetuses with oligohydramnios of long duration. Of fetuses in the cephalic presentation, 10 of 12 (83%) surviving dolichocephalic fetuses had respiratory distress syndrome compared with 31 of 73 (42%) normocephalic fetuses. However, other outcome parameters did not differ significantly. We conclude that the finding of dolichocephaly is associated with oligohydramnios of long duration. In fetuses with preterm premature rupture of membranes it is associated with respiratory distress syndrome, but not otherwise with a poor neonatal prognosis.

Breech Presentation↗
PubMed1996

Test-retest reliability of the Chattecx Balance System in the patient with hemiplegia.

The purpose of this study was to determine the test-retest reliability of the Chattecx Balance System in the patient with hemiplegia. Twenty patients (14 male, 6 female; 14 right hemiplegia, 6 left; mean age 69.5, range 32-86 years) undergoing physical therapy, were tested on the Chattecx Balance System at the same time on 3 consecutive days. Subjects were tested on a static platform, and also using linear translation (anterior-posterior movements), and rotational angular motion about a mediolateral axis. Day 1 was used to allow the patient to become familiar with the testing equipment and the protocol. Data collected from days 2 and 3 were compared statistically using Intraclass Correlation Coefficient (ICC) formula 3,1. Comparison of the center of pressure in the mediolateral direction (COBX), the center of pressure in the anteroposterior direction (COBY), and dispersion index were analyzed for each of the three protocols. ICCs ranged from 0.58 to 0.92 for the static platform, 0.46 to 0.83 for the linear translations, and 0.62 to 0.89 for the angular rotations. Results using this testing protocol showed COBX to be highly reliable for the static and moderately reliable for linear and angular testing protocols. COBY was not reliable for any test condition. Dispersion was moderately reliable only for the static and angular testing protocols. From a clinical standpoint, measures that were found to be highly or moderately reliable may be useful for demonstrating the progress of patients with hemiplegia in their rehabilitation programs.

Adult↗
PubMed1995

Pylorus subjacent to the gallbladder: an additional finding in hypertrophic pyloric stenosis.

We have noted that sonographically positive cases of hypertrophic pyloric stenosis (HPS) demonstrate a distortion of normal anatomy in which the elongated pylorus displaces the duodenum and lies adjacent to and below the gallbladder. Ten consecutive cases of HPS diagnosed by ultrasound were reviewed. In each case the pylorus was imaged subjacent to the gallbladder. Sonograms from 100 infants from a different institution were then reviewed. There were 13 cases with the pylorus subjacent to the gallbladder, 12 of these met criteria for HPS. Recognition of this anatomic relationship may aid in the diagnosis of HPS.

Gallbladder↗
PubMed1995

Presumed vestibular hemorrhage secondary to warfarin.

Hemorrhage secondary to anticoagulant therapy is well documented. We report a patient who presented with acute vertigo and unilateral deafness while on warfarin and was found to have a probable hemorrhage in the labyrinth, identified on MRI.

Aged↗
PubMed1995

Change in endometrial thickness in postmenopausal women undergoing hormone replacement therapy.

PURPOSE: To evaluate the effect over time of hormone replacement on endometrial thickness in asymptomatic postmenopausal women. MATERIALS AND METHODS: Endometrial thickness was measured on 644 sonograms of 120 postmenopausal volunteers receiving no hormones or one of three hormone regimens. Each subject underwent ultrasound (US) two to nine times. In addition, eight women using sequential hormones underwent US seven to 20 times over 2 months. The greatest endometrial thickness and change in endometrial thickness over time were evaluated. RESULTS: Endometrial thickness was statistically significantly greater in women using sequential hormones (8 mm) compared with that in control subjects (5 mm). Change in endometrial thickness (> 3-mm difference) was seen in 23 of 40 women using sequential hormones compared with six of 61 controls. Women using sequential hormones demonstrated maximum endometrial thickness on days 13-23 of the cycle. CONCLUSION: Women using sequential hormones show greater endometrial thickness than that in controls and show the most variation in measurements. They should undergo US either early or late in the hormone cycle to evaluate the endometrium at its thinnest.

Abdomen↗
PubMed1995

The sonographic appearance of renal transplants during pregnancy.

This study evaluates the sonographic appearance of renal allografts during pregnancy. Baseline and intrapartum sonograms and serum creatinine levels from 19 women with 24 pregnancies were evaluated. In 15 of the 22 pregnancies with more than one examination, renal dilatation increased during gestation. The degree of dilatation was minimal to mild, with moderate dilatation present only in the third trimester. There were no cases of severe dilatation. Change in renal dilatation was seen in eight of eight patients with normal renal function, four of six patients with moderate renal impairment, and in zero of two patients with severe renal impairment. Normal transplant morphology or a single abnormal criterion was found in 23 of 24 pregnancies. Transplant morphology is not affected by pregnancy. Renal allografts in asymptomatic patients frequently demonstrate minimal to mild dilatation during pregnancy. The ability of the transplant kidney to dilate decreases with worsening renal function.

Adult↗
PubMed1995

Imaging the fetal abdomen: how efficacious are the AIUM/ACR guidelines?

This study was performed to evaluate the efficacy of the American Institute of Ultrasound in Medicine/American College of Radiology guidelines for the detection of fetal abdominal abnormalities. In Part 1 of the study, images from 100 fetuses with sonographically diagnosed abdominal anomalies were masked except for one view of the abdominal circumference, stomach, renal area, bladder, and cord insertion. Ninety-six cases were recognized as abnormal by two sonologists. In Part 2, sonograms of 70 normal fetuses and 30 abnormal fetuses were similarly masked and shown to a sonographer and a fourth year radiology resident. Each identified 29 of 30 abnormal cases. Among fetuses with abdominal anomalies detectable at a prenatal diagnostic center, the majority of abnormal fetuses could be identified by evaluation of the five AIUM/ACR recommended views.

Abdomen↗
PubMed1995

Myocardial technetium-99m-teboroxime activity in acute coronary artery occlusion and reperfusion: relation to myocardial blood flow and viability.

UNLABELLED: The purpose of this study was to test the hypothesis that 99mTc-teboroxime retention within the heart depends at least in part on the presence of viable myocytes. METHODS: We used a porcine model of acute myocardial infarction with reperfusion and compared the myocardial uptake of labeled microspheres at 1 hr of reperfusion with that of 99mTc-teboroxime. Eleven domestic swine had measurements of hemodynamics and regional myocardial blood flow (microspheres) at baseline, at 10 and 50 min of left anterior descending (LAD) coronary artery occlusion and at 10 and 60 min of LAD reperfusion. Technetium-99m-teboroxime was injected intravenously at 60 min of reperfusion and the animal was killed 5-7 min later. The heart was then perfused with triphenyl tetrazolium chloride to identify infarcted and jeopardized myocardium in the occlusion zone and with Evans blue dye to mark normally perfused myocardium. After imaging, tissue sections were digested and colored microspheres were extracted and counted to determine myocardial blood flow. RESULTS: After coronary occlusion, infarct zone (MIZ) to normal zone (NZ) blood flow ratios declined from 0.95 +/- 0.27 (pre-occlusion) to 0.18 +/- 0.15 at 10 min and 0.25 +/- 0.35 at 50 min of occlusion (both p < 0.05). The MIZ:NZ count ratio at 60 min of reperfusion was less than the MIZ:NZ blood flow ratio in every animal and over the entire range of flow ratios (0.55-3.64). CONCLUSION: Technetium-99m-teboroxime requires viable myocytes for retention within the heart and is not exclusively a tracer of myocardial blood flow when imaged 5-7 min after injection. Additional in vivo imaging studies are required to determine the extent to which reduced retention of the tracer by reperfused but nonviable myocardium influences the appearance of clinical scans.

Animals↗
PubMed1994

Cytochemical characteristics of neurons in the trigeminal mesencephalic nucleus of hatchling chicks.

The goal of the present study was to identify cytochemical markers characteristic of muscle afferents in hatchling chicks. To this end, we stained neurons in the trigeminal mesencephalic nucleus with a variety of markers that label subsets of neurons in avian dorsal root ganglia. We found that trigeminal mesencephalic neurons are surprisingly heterogeneous in their cytochemical make-up, expressing, to varying degrees, substance P, cholecystokinin, carbonic anhydrase, calbindin D-28k, parvalbumin, and S-100 beta. Calbindin D28k and S-100 beta appeared to be expressed equally in medial and lateral divisions of the trigeminal mesencephalic nucleus. In contrast, substance P- and cholecystokinin-immunoreactive neurons were more abundant in the medial division, whereas carbonic anhydrase activity and parvalbumin immunoreactivity were stronger in the lateral division. We were unable to detect met-enkephalin, neuropeptide Y, calcitonin gene-related peptide, vasoactive intestinal peptide, somatostatin, gamma-aminobutyric acid, or tyrosine hydroxylase in the trigeminal mesencephalic nucleus. Moreover, these neurons did not appear to bind the lectin Dolichos biflorus agglutinin. The heterogeneity of expression of markers among trigeminal mesencephalic nucleus neurons, especially between neurons in the medial and lateral divisions, suggests that these neurons are functionally diverse.

Animals↗
PubMed1994

Teratogen exposure: lack of morphological abnormalities by detailed fetal sonography.

Teratogen exposures cause 1-2% of congenital abnormalities. Our anecdotal experience was that detailed fetal sonograms conducted for the indication of teratogen exposure failed to demonstrate significant morphological abnormalities. We reviewed our experience to see how often such examinations yielded positive results. Records from 11 September 1989 to 13 September 1993 were reviewed. All women referred for detailed fetal sonography for the sole indication of exposure to drugs, toxins, or infectious agents and with a sonographic age of 16-24 menstrual weeks were included. All exposures were included in the study, even those without known teratogenic potential. Patients previously diagnosed with a morphological abnormality or with an abnormal level of maternal serum alpha-fetoprotein were excluded.A total of 125 women with 126 singleton pregnancies comprised the study population. Ten women had multiple exposures. Including the multiple exposures, there was a total of 138 exposures, 104 to drugs and other toxins (45 of which were not known human teratogens), and 34 to infections. The only significant morphological abnormality found was a duplicated kidney in a woman with parvovirus exposure. While parvovirus is a cause of anemia and hydrops, it is not a known human teratogen. We therefore assume that this was a coincidental association. We conclude that teratogen exposure is a low-yield indication for detailed fetal sonography.

Journal Article↗
PubMed1994

Internal fixation of proximal humerus fractures using the screw-tension band technique.

Many of the current techniques of internal fixation of proximal humerus fractures use tension band wires to achieve secure fixation, allowing immediate postoperative exercise of the affected limb. In addition, the use of a cancellous lag screw placed from the humeral shaft into the humeral head may have several advantages. In particular, this lag screw does not violate the subacromial space and provides initial stability between the head and shaft, which facilitates placement of the tension band wires. This technique was used in 13 patients whose average age was 71 years (range 54-86). Follow-up averaged 20 months. Eight patients had two-part fractures and five patients had three-part fractures. This technique used a deltopectoral approach with manual impaction of the humeral head and shaft. A 6.5-mm AO screw was used for lag screw fixation in addition to two 18-gauge tension band wires: one placed through the tuberosities and one under the rotator cuff tendons. Passive range of motion of the involved shoulder was begun with the first postoperative week, and active range of motion and strengthening were allowed after the fourth postoperative week. At follow-up patients were evaluated for range of motion, function, pain, and radiographic appearance of the fracture. Average forward flexion was 160 degrees, external rotation was 46 degrees, and internal rotation was to the 10th thoracic vertebra. According to the functional scale proposed by Hawkins, 10 of the 13 patients had achieved a good result. Two of the remaining patients had a fair score, and one had a poor outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗
PubMed1994

Adaptive responses of coronary circulation and myocardium to chronic reduction in perfusion pressure and flow.

We tested the hypothesis that chronic reduction in perfusion pressure and flow in the coronary circulation induces a state of myocardial "hibernation" characterized not only by a steady-state reduction in myocardial O2 consumption (MVO2) but also by evidence of persistent dilator reserve of the distal vasculature. Biochemical and morphological changes in the coronary vasculature were also assessed. Experiments were conducted in swine with an extraluminal coronary stenosis placed 4-32 wk before study. Stenosis reduced lumen diameter by approximately 80% at the time of final experimentation. Baseline, regional myocardial blood flow distal to the stenosis in both endocardial and epicardial layers was reduced vs. that of the normal zone. Vasodilator reserve persisted in both endocardial and epicardial layers of the stenosis zone. Flow increased in each layer in response to adenosine plus phenylephrine and failed to decline despite a marked reduction in perfusion pressure in response to adenosine alone. Regional MVO2 at baseline was reduced vs. historical controls without coronary stenosis. Protein synthesis rate in coronary vessels of the stenosis zone was reduced vs. that of the normal zone. Morphological responses of stenosis zone vessel walls were heterogeneous. Smaller microvessels exhibited mild hypertrophy of their walls, whereas walls of larger microvessels tended to atrophy. Thus chronic reduction in perfusion pressure and flow induces a state of myocardial hibernation characterized by a steady-state reduction in MVO2 in association with persistent dilator capacity. Biochemical and morphological changes occur in microvessel walls and may contribute to observed physiological responses.

Acclimatization↗