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Biomedical subjects

D Levine

Publications and source records attributed to D Levine.

At least 73 records · Page 4Linked to original sources
PubMed1998

Unipolar versus bipolar hemiarthroplasty for the treatment of femoral neck fractures in the elderly.

This paper presents the short term results of an ongoing prospective randomized trial comparing a cemented unipolar with a cemented bipolar hemiarthroplasty for the treatment of displaced femoral neck fractures in the elderly. Forty-seven patients with an average age of 77 years completed 6-month followup. Outcomes at 6 weeks, 3 months and 6 months were assessed by completion of a patient oriented hip outcome instrument and by functional tests of walking speed and endurance. No differences in the postoperative complication rates or lengths of hospitalization were seen between the two groups. Patients treated with a bipolar hemiarthroplasty had greater range of hip motion in rotation and abduction and had faster walking speeds. However, no differences in hip rating outcomes were found. These early results suggest that use of the less expensive unipolar prosthesis for hemiarthroplasty after femoral neck fracture may be justified in the elderly.

Aged↗
PubMed1997

Minimally invasive plate osteosynthesis of distal fractures of the tibia.

Minimally invasive plate osteosynthesis of distal tibial fractures is technically feasible and may be advantageous in that it minimizes soft tissue compromise and devascularization of the fracture fragments. The technique involves open reduction and internal fixation of the associated fibular fracture when present, followed by temporary external fixation of the tibia until swelling has resolved. Subsequent limited, but open reduction and internal fixation of the articular fragments when displaced followed by minimally invasive plate osteosynthesis of the tibia utilizing precontoured tubular plates and percutaneously placed cortical screws is performed. The semitubular plate was chosen because it adapts more easily to the bone contours than the stiffer small fragment LC-DCP does. Twenty patients (age 25-59 years) with unstable intraarticular or open extraarticular fractures have been treated including 12 A-type, 1 B-type and 7 C-type fractures according to the AO classification. Two fractures were open (both Gustilo Type I). Closed soft tissue injury was graded according to Tscherne with 3 type C0, 7 type C1, 7 type C2 and 1 type C3. All fractures healed without the need for a second operation. Time to full weight-bearing averaged 10.7 weeks (range 8-16 weeks). Two fractures healed with > 5 degrees varus alignment and 2 fractures healed with > 10 degrees recurvatum. No patient had a deep infection. The average range of motion in the ankle for dorsiflexion was 14 degrees (range 0-30 degrees) and plantar flexion averaged 42 degrees (range 20-50 degrees). With longer follow-up and a larger number of patients, the authors feel confident that the minimally invasive technique for plate osteosynthesis for the treatment of distal tibial fractures will prove to be a feasible and worthwhile method of stabilization while avoiding the severe complications associated with the more standard methods of internal or external fixation of those fractures.

Adult↗
PubMed1997

The role of exercise and physical modalities in the treatment of osteoarthritis.

Physical rehabilitation is a valuable and often underutilized part of the overall management of small animals with OA. A team consisting of the veterinarian, physical therapist, veterinary technician, and owner is vital to determine and carry out an appropriate therapeutic regimen. To maintain enthusiasm for the program, measurements should be regularly obtained to document progress. In addition, controlled studies should be performed to determine the degree of improvement that may be expected with physical rehabilitation programs.

Animals↗
PubMed1997

Emotion processing in borderline personality disorders.

The aim of this study was to examine the ways in which adults with borderline personality disorder (BPD) experience and manage their feelings. Responses of 30 subjects who met the criteria for BPD on the Structured Clinical Interview for DSM-III-R were compared with 40 non-BPD controls on the following measures of emotion processing and affect regulation: 1) level of emotional awareness, 2) capacity to coordinate mixed valence feelings, 3) accuracy at identifying facial expressions of emotion, and 4) intensity of response to negative emotions. The results showed significant differences between the two groups on all measures. The borderlines showed significantly lower levels of emotional awareness, less capacity to coordinate mixed valence feelings, lower accuracy at recognizing facial expressions of emotion, and more intense responses to negative emotions than the nonborderline controls. The findings corroborate clinical observations of borderline patients' difficulties in regulating emotions. The implications of the results for the therapeutic management of BPD patients are discussed.

Adaptation, Psychological↗
PubMed1997

Fetal central nervous system anomalies: MR imaging augments sonographic diagnosis.

PURPOSE: To evaluate fetuses with sonographically suspected central nervous system anomalies to determine the frequency with which obstetric magnetic resonance (MR) imaging adds clinically useful information to that provided by ultrasonography (US). MATERIALS AND METHODS: US and MR images and diagnoses in 18 pregnant women were reviewed and compared by two radiologists. Postnatal physical examination and imaging findings and fetal autopsy results were standards. Referring physicians were questioned as to how the additional information provided by MR imaging changed patient counseling. RESULTS: In 10 (55%) patients, MR imaging demonstrated 11 additional findings. These findings were agenesis of the corpus callosum (n = 4), cerebellar hypoplasia (n = 2), cortical cleft (n = 2), polymicrogyria (n = 1), porencephaly (n = 1), and partial agenesis of the septi pellucidi (n = 1). In seven (39%) patients, additional information provided by MR imaging altered counseling. In one case of suspected agenesis of the corpus callosum, diagnosis at MR imaging was at least partially incorrect. CONCLUSION: US and MR imaging are complementary imaging methods in the evaluation of high-risk pregnancy. When a central nervous system anomaly is suspected at US, MR imaging may demonstrate additional findings that can alter patient counseling.

Central Nervous System↗
PubMed1997

Treatment of ectopic pregnancy: is a human chorionic gonadotropin level of 2,000 mIU/mL a reasonable threshold?

PURPOSE: To determine whether a human chorionic gonadotropin (hCG) level of 2,000 mIU/mL is a reasonable threshold for diagnosing ectopic pregnancy in the absence of ultrasound (US) findings of intrauterine pregnancy (IUP) and thus to prevent inappropriate treatment that will result in the loss of an otherwise normal pregnancy in women with early IUPs. MATERIALS AND METHODS: The authors reviewed the medical records of and US scans obtained in 676 patients in whom ectopic pregnancy was clinically suspected between January 1, 1994, and December 31, 1995. RESULTS: Five hundred forty-eight patients had evidence of a normal or abnormal IUP. Fifty-one (40%) of the 128 patients without evidence of an IUP had an hCG level of more than 2,000 mIU/mL. Of these 51 patients, 15 (29%) were treated for ectopic pregnancy; 17 (33%) were not immediately treated for ectopic pregnancy and had a normal IUP at follow-up US. CONCLUSION: An hCG level of 2,000 mIU/mL without US findings of IUP, while suggestive of an abnormal pregnancy, is not diagnostic. Per the results of recent studies, it is reasonable to closely follow up rather than treat many of these early, stable cases of ectopic pregnancy.

Adult↗
PubMed1997

Placenta accreta: evaluation with color Doppler US, power Doppler US, and MR imaging.

PURPOSE: To determine the value of transabdominal ultrasound (US), transvaginal US, color Doppler US, power Doppler US, and magnetic resonance (MR) imaging in the diagnosis of placenta accreta. MATERIALS AND METHODS: Nineteen patients in the third trimester of pregnancy who were at risk for placenta accreta underwent color Doppler and power Doppler US; 18 patients also underwent MR imaging. Images were interpreted prospectively for signs of accreta by two reviewers. The reviewers' confidence in their diagnosis was graded on a five-point scale. RESULTS: Outcomes at delivery were as follows: normal placenta (n = 11), hysterectomy owing to uncontrollable bleeding (n = 1), and placenta accreta (n = 7). Five cases of lower-uterine-segment placenta accreta were diagnosed with a high level of confidence with vaginal and power Doppler US. In one patient with a posterior placenta who had previously undergone myomectomy, MR imaging enabled the diagnosis of placenta accreta, which was not well depicted at US. CONCLUSION: In patients with a history of uterine scars, vaginal US with power Doppler US performed well in the evaluation of lower-uterine-segment placenta accreta. MR imaging depicts posterior placenta accreta.

Female↗
PubMed1997

Imaging of pelvic postpartum complications.

Differentiation between endometritis and RPOC in febrile postpartum patients is commonly requested by clinicians. Sonography is the screening technique of choice to assess the endometrial contents. For cases in which the retained placenta is calcified or still has demonstrable blood flow, a specific diagnosis of RPOC can be made. In more complicated cases, a CT scan or an MR image may be requested. In addition to evaluating the uterus and any intra- or extrauterine fluid collections, attention must be paid to the ovarian veins to exclude the diagnosis of ovarian vein thrombosis.

Adult↗
PubMed1997

The effect of oligohydramnios on detection of fetal anomalies with sonography.

OBJECTIVE: The sonographic examination of fetuses is generally thought to be compromised when oligohydramnios is present because of the subjective impression of less adequate visualization of fetal anatomy. The aim of this study was to evaluate the extent to which oligohydramnios limits our ability to detect major anomalies on sonograms. MATERIALS AND METHODS: Records from the University of California, San Francisco from March 4, 1989 through January 4, 1994, were reviewed to identify all cases of premature rupture of the membranes in patients who then underwent nontargeted sonography. Sonographic results in pregnancies with oligohydramnios and without oligohydramnios (control population) were compared. Follow-up was obtained from a perinatal database, autopsy reports, and medical records. RESULTS: We found 345 patients with a history of premature rupture of the membranes (175 with oligohydramnios, 170 without oligohydramnios). Gestational age of fetuses was 16-38 weeks. Major congenital anomalies, including hydronephrosis, ventriculomegaly, intestinal atresias, hydrops, congenital diaphragmatic hernia, skeletal dysplasias, cloacal malformations, and gastroschisis, were revealed on sonography in 13 of 175 pregnancies with oligohydramnios and in 17 of the 170 pregnancies in the control group. Major anomalies missed in the oligohydramnios group included cardiac anomalies, club foot, small ventral hernia, limb reduction defect, and anal atresia. Major anomalies missed in the control group were club foot, anal atresia, and tracheoesophageal fistula. All of the major anomalies missed in both groups were of the type that are known to be difficult to diagnose before birth and that are frequently missed on sonography. CONCLUSION: Although oligohydramnios subjectively degrades image resolution, sonography still reveals important fetal anatomic landmarks. Major anomalies can be detected on sonography even when the pregnancy has less than the normal amount of amniotic fluid.

Case-Control Studies↗
PubMed1997

Maternal postural challenge as a functional test for cervical incompetence.

We studied the effect of an upright maternal position on the cervix. Of 41 high risk patients (17 to 33 weeks' gestational age), 14 of 16 who had a greater than 33% decrease in cervical length in the upright position compared to supine position delivered their infants prematurely, compared to 1 of 25 patients who had a decrease of less than 33% (P < 0.0005). No change in the cervical length was noted in 24 low-risk patients, all of whom were delivered at term. When the finding of a cervical length of less than 2 cm was combined with a postural change, the sensitivity for prediction of preterm delivery was 100%. We conclude that for patients at high risk for incompetent cervix, maternal posture-related cervical shortening can assist in predicting those who will undergo premature delivery.

Adult↗
PubMed1996

Progress toward chemical accuracy in the computer simulation of condensed phase reactions.

We describe a procedure for the generation of chemically accurate computer-simulation models to study chemical reactions in the condensed phase. The process involves (i) the use of a coupled semiempirical quantum and classical molecular mechanics method to represent solutes and solvent, respectively; (ii) the optimization of semiempirical quantum mechanics (QM) parameters to produce a computationally efficient and chemically accurate QM model; (iii) the calibration of a quantum/classical microsolvation model using ab initio quantum theory; and (iv) the use of statistical mechanical principles and methods to simulate, on massively parallel computers, the thermodynamic properties of chemical reactions in aqueous solution. The utility of this process is demonstrated by the calculation of the enthalpy of reaction in vacuum and free energy change in aqueous solution for a proton transfer involving methanol, methoxide, imidazole, and imidazolium, which are functional groups involved with proton transfers in many biochemical systems. An optimized semiempirical QM model is produced, which results in the calculation of heats of formation of the above chemical species to within 1.0 kcal/mol (1 kcal = 4.18 kJ) of experimental values. The use of the calibrated QM and microsolvation QM/MM (molecular mechanics) models for the simulation of a proton transfer in aqueous solution gives a calculated free energy that is within 1.0 kcal/mol (12.2 calculated vs. 12.8 experimental) of a value estimated from experimental pKa values of the reacting species.

Journal Article↗
PubMed1996

The noninvasive diagnosis and management of a uterine arteriovenous malformation.

BACKGROUND: Successful nonsurgical therapy of uterine arteriovenous malformations is rare, with most cases being diagnosed at hysterectomy. CASE: A uterine arteriovenous malformation was diagnosed by Doppler ultrasound, and its resolution after 1 week of treatment with methylergonovine maleate was observed. CONCLUSION: Although there are case reports regarding treatment of uterine arteriovenous malformations by embolization performed by interventional radiology, to our knowledge, the noninvasive long-term management of a uterine arteriovenous malformation has not been reported.

Adult↗
PubMed1996

Effect of manufacturing tolerances on the micromotion at the Morse taper interface in modular hip implants using the finite element technique.

This study reports on the examination of the effect of manufacturing tolerances on the micromotion at the Morse taper interface in modular hip implants. The finite element technique was used as a tool of analysis. Special emphasis was placed on the consideration of the transient dynamic conditions under which a prosthesis works inside the human body. In order to simulate approximately the repetitive forces acting on a hip implant during the human walking cycle, a time-variant sinusoidal load was applied on the head of the taper. The locking of the Morse taper joint by the surgeon in the operating room at the time of implantation was simulated by specifying an axial displacement to the female taper component as an initial condition.

Biomechanical Phenomena↗
PubMed1996

Trimethaphan versus sodium nitroprusside for the control of proximal hypertension during thoracic aortic cross-clamping: the effects on spinal cord ischemia.

Sodium nitroprusside (SNP) has been used to control the proximal hypertension associated with thoracic aortic cross-clamping (TACC) during thoracic aortic surgery. It worsens neurologic outcome, presumably by further decreasing distal arterial pressure and increasing cerebrospinal fluid (CSF) pressure, thereby worsening the spinal cord perfusion pressure (SCPP). Trimethaphan does not increase CSF pressure. Therefore, the present study investigates the effect of trimethaphan versus SNP to control proximal hypertension during TACC on neurologic outcome. Two groups, each with eight mongrel dogs, were studied. All animals underwent descending TACC for 45 min. The mean proximal aortic blood pressure was maintained at 95-100 mm Hg by the use of SNP or trimethaphan. Distal aortic pressure was allowed to vary. The dogs were neurologically evaluated 24 and 48 h later by a blinded observer. During cross-clamping, there was no difference in mean proximal aortic pressure between groups. After 10 min of cross-clamping, distal aortic pressure was higher (P < 0.01), CSF pressure was lower (P < 0.01), and SCPP was higher (P < 0.005) in the trimethaphan group as compared with the SNP group (group effect). Neurologic outcome as assessed by Tarlov's score was better at 24 and 48 h in the trimethaphan group (P < 0.05). Histopathologic injury trended with worsened neurologic outcome. We conclude that 1) trimethaphan produced higher SCPP than SNP, and 2) neurologic outcome was better in the trimethaphan group.

Animals↗