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Biomedical subjects

R B Lee

Publications and source records attributed to R B Lee.

At least 55 records · Page 3Linked to original sources
PubMed1990

Three or more rib fractures as an indicator for transfer to a Level I trauma center: a population-based study.

UNLABELLED: The presence of major chest wall injury is an indication for transfer to a Level I trauma center. We hypothesized that the presence of three or more rib fractures on initial chest X-ray would identify a small subgroup of patients with a high probability of requiring trauma center care. All trauma discharges in Maryland between 1984 and 1986 (N = 105,683) were reviewed. Patients were divided by the presence of rib fractures (no rib fractures, 1-2 fractures, 3+ fractures) and age in years (0-13, 14-64, 65+). RESULTS: The presence of three or more rib fractures in the pediatric age group was rare and precluded further evaluation. When comparing patients with 1-2 rib fractures versus 3 or more rib fractures, significant differences were found in mortality, mean Injury Severity Score, mean hospital stay and mean number of ICU days (p less than 0.001). The significant differences occurred in all age groups 14 years old and older. The presence of three or more rib fractures increased the relative risk of splenic injury (6.2) and liver injury (3.6) but did not predict the presence of aortic injury. CONCLUSION: The presence of 3 or more rib fractures identifies a small subgroup of patients (2.4%) likely to require tertiary care. This triage tool is useful in all patients over the age of 14 years.

Adolescent↗
PubMed1990

Evaluation of subclavian catheters in gynecologic cancer patients.

Sixty-eight semipermanent subclavian catheters were placed in 61 patients with gynecologic malignancies. The principal indicator for placement was chemotherapeutic administration. Other uses included blood transfusion, antibiotic infusion, and hyperalimentation. The minor complication rate of 21% included exit site infections and clotted, broken, and dislodged catheters. There were no acute surgical complications; i.e., bleeding or pneumothorax, but there was a 6% major complication rate, which included four cases of sepsis and a case of a broken intravascular catheter.

Adult↗
PubMed1990

Classification of endometrial cells on cervical cytology.

One hundred eighty-eight women who had endometrial cells on cervical cytologic specimens during the secretory phase or in the postmenopausal period were studied retrospectively. Each had undergone hysterectomy or endometrial biopsy within 12 months of the original smear. The endometrial cells were classified as typical, atypical, or suspicious for carcinoma. Among premenopausal subjects, three of 57 with typical cells had endometrial hyperplasia, one of two with atypical cells had endometrial polyps, and both with cells suspicious for carcinoma had endometrial carcinoma. In the postmenopausal group, ten (13.5%) of 74 with typical endometrial cells had either hyperplasia or carcinoma, and five (22.7%) of 22 with atypical cells and 24 77.4%) of 31 patients with suspicious cells had either hyperplasia or carcinoma. The present findings and a review of the pertinent literature demonstrate that the classification system used is helpful in predicting the risk for endometrial disease in patients with endometrial cells seen on cervical cytologic smears during the secretory phase or in the postmenopausal period.

Adult↗
PubMed1990

The significance of moderate and severe inflammation on class I Papanicolaou smear.

The significance of a cytologic diagnosis of moderate and severe inflammation with a normal (class I) Papanicolaou smear has not been addressed. A retrospective review of 596 consecutive cervical smears performed over 13 months revealed 85 women who had a class I cytologic smear with moderate to severe inflammation. Seventy-eight patients had colposcopic examinations and were considered for this study. Fifty-nine (75.6%) had cervical punch biopsies and/or endocervical biopsies. Of the 78, 19 (24.4%) had cervical condylomata and nine (11.5%) had cervical intraepithelial neoplasia. We conclude that class I cytologic smears with moderate to severe inflammation may be associated with findings of condylomata and cervical dysplasia.

Biopsy↗
PubMed1989

Presence of three or more rib fractures as an indicator of need for interhospital transfer.

During a 42-month period, 3,282 patients with blunt trauma were admitted to our hospital. Group I (n = 3,143) was defined as patients sustaining zero to two rib fractures, Group II (n = 139) as patients sustaining three or more rib fractures. Groups I and II differed in age and mechanism of injury. Two other descriptive variables (sex and year of admission) showed statistically significant associations with outcome. To adjust for the joint effect of these four variables, a log-linear model (binary outcomes) or a linear regression model (continuous outcomes) was used. We defined need for interhospital transfer (NIT) based on the following: death, an Injury Severity Score of greater than or equal to 16, or direct admission to the operating room or intensive care unit. We conclude that the presence of three or more rib fractures identified a group of patients requiring transfer to a trauma center (positive predictive value = 92.8%). A population-based study is needed to verify this finding.

Adult↗
PubMed1989

Effect of firing temperature and water exposure on crack propagation in unglazed porcelain.

Static fatigue of dental ceramics results from the interaction of residual tensile stress and an aqueous environment. This phenomenon is a potential cause of delayed crack formation and propagation in ceramic or metal-ceramic restorations. For dental ceramics, the influence of microstructural defects such as porosity or fissures caused by incomplete sintering is not known. The objectives of this study were to characterize the influence of porosity (produced by underfiring) on the crack propagation resistance of two feldspathic porcelains and to determine whether lower stress corrosion susceptibility or higher fracture toughness accounts for the superior thermal shock resistance of one of these ceramics. We underfired bars of each porcelain, 25 mm x 4 mm x 4 mm, by as much as 84 degrees C below their recommended firing temperatures. After polishing the specimens through 0.05 microns alumina, we induced cracks in their surfaces with a Vickers microhardness indenter. Semicircular cracks, which were produced under an applied indenter load of 19.6 N, grew with time during storage in distilled water at 37 degrees C. Underfiring of both ceramics caused a slight increase in fracture toughness and a relatively small change in pore volume fraction until we underfired the ceramics at 30 degrees C or more. The crack propagation data indicate that the higher thermal shock resistance of one of the ceramics--as measured previously by a water-quench technique-may be due to its greater resistance to stress corrosion at the initial stage of crack propagation.

Dental Porcelain↗
PubMed1989

Evaluation of serum haptoglobin levels in patients with adnexal masses.

Over a four-year period, serum haptoglobin was measured in 152 patients with adnexal masses in an attempt to discriminate between benign and malignant disease. When serum haptoglobin exceeded 150 mg/dl, malignancy could be identified with a sensitivity of 83% and a specificity of 84%. While the predictive value of a positive test is only 66%, the predictive value of a negative test is 93%, and this inexpensive test may be clinically useful. Stage, grade, and size of tumor did not correlate with serum haptoglobin levels.

Adnexa Uteri↗
PubMed1989

Pregnancy following conservative surgery and adjunctive chemotherapy for stage III immature teratoma of the ovary.

A 24-year-old woman with stage III grade 3 immature teratoma of the ovary was treated with a unilateral salpingo-oophorectomy and nine courses of vincristine, actinomycin D, and cyclophosphamide combination chemotherapy. She had a negative second-look exploration; 30 months after initial surgery she became pregnant, and subsequently delivered a normal child at term. This is the first report of a successful pregnancy following conservative surgery and chemotherapy for advanced-stage immature teratoma.

Adult↗
PubMed1989

Pharmacokinetics of superoxide dismutase during hypothermic cardiopulmonary bypass.

We evaluated the plasma elimination of recombinant human superoxide dismutase (rHSOD) when given before reperfusion in an experimental canine model of global hypothermic myocardial ischemia. Adult mongrel dogs were placed on cardiopulmonary bypass, and core temperature was reduced to 25 degrees C. Hypothermic global myocardial ischemia was maintained for 90 minutes with intermittent crystalloid cardioplegic solution. Five minutes before reperfusion, rHSOD was administered via the pump oxygenator as a bolus injection. Plasma rHSOD levels were measured at 0, 3, 5, 10, 20, 30, 60, and 120 minutes after injection. Animals were rewarmed and weaned from bypass. Three experimental groups received either 4, 8, or 16 mg/kg rHSOD. Based on previously reported dose-response data, we conclude that desirable peak serum concentrations are achieved with 16 mg/kg rHSOD. In the setting of hypothermic cardiopulmonary bypass and global myocardial ischemia, single bolus administration of rHSOD before reperfusion is an effective method due to the prolonged serum half-life.

Animals↗
PubMed1988

Surgical treatment of acute traumatic tear of the thoracic aorta.

Acute traumatic tear of the thoracic aorta is a severe injury with a high mortality rate. This condition requires expeditious evaluation and prompt surgical intervention in order to improve patient survival. The experience at the authors' institution from 1971 to 1987 includes 41 patients who sustained acute traumatic tear of the thoracic aorta and reached the hospital alive. The purpose of the study was to evaluate the surgical management of this injury with regards to mortality rate and the incidence of spinal cord injury. Five patients died from exsanguination before definitive repair could be undertaken. Thirty-six patients had repair of traumatic aortic tear in the area of the isthmus. Nine patients were operated upon with the clamp and sew technique, 20 patients had a heparin-bonded shunt placed, and seven patients were treated by repair with cardiopulmonary bypass. There were five operative deaths that were not related to the technique employed. Two patients without preoperative evidence of spinal cord injury developed paraparesis. No patient had postoperative paraplegia. Despite rapid transport, expeditious evaluation, and emergency thoracotomy, some patients die from exsanguination prior to definitive repair. Even with the provision of distal aortic perfusion during clamping, the risk of spinal cord injury is not eliminated.

Adolescent↗
PubMed1988

Do multi-lumen catheters increase central venous catheter sepsis compared to single-lumen catheters?

Triple-lumen catheters (TLC) are now routinely used in critically ill and multiply injured patients who require multi-port central venous access. An apparent rise in catheter contamination and catheter-related sepsis (CRS) occurred in patients receiving total parenteral nutrition (TPN) through a TLC as opposed to a single-lumen catheter (SLC). A prospective study was performed to determine rates of catheter contamination and CRS in multiple trauma and general surgical-medical patients who received TPN through TLC's and SLC's. Three hundred seven TLC's and 68 SLC's were placed in 234 patients during a 12-month period. There was no statistically significant difference in the rate of contamination or CRS between the two groups although there was a trend toward increased CRS and contamination in the TLC group. TLC's may be used for short-term administration of TPN without significant increase in catheter contamination or CRS.

Bacterial Infections↗
PubMed1988

Influence of contraction mismatch and cooling rate on flexural failure of PFM systems.

The interactive influence of cooling rate and the sign and magnitude of thermal contraction difference between metals and ceramic veneers on bond strength have not been extensively analyzed, although numerous bond-test studies have been reported during the past two decades. A previous analytical study of residual incompatibility stress in bond-test specimens indicated that bond strength values may be of relatively little value if the residual stress state of the metal-ceramic specimens is not considered. The objective of this study was to determine the influence of cooling rate and contraction mismatch on the flexural failure resistance of metal opaque-porcelain strips. Specimens were subjected to four-point loading in an Instron testing machine until crack initiation occurred at the metal-ceramic interface. The residual stress states in the ceramic region were estimated from finite element stress analyses of the bond-test specimens by use of dilatometry data obtained at the cooling rate of 3 degrees C/min. The total stress induced from the residual stress and the applied flexural load was also determined for these specimens. Statistical analyses of the experimental data revealed that the slowly cooled specimens exhibited a significantly lower (p < 0.05) flexural strength compared with rapidly cooled specimens. Regardless of the cooling technique, metal-ceramic specimens with a negative thermal contraction difference (alpha m - alpha p < 0) failed at significantly lower (p < 0.05) flexural loads than did specimens with a positive thermal contraction difference.

Analysis of Variance↗
PubMed1988

Delayed crack development in porcelain due to incompatibility stress.

Delayed failure of metal-ceramic restorations due to static fatigue can occur when residual tensile stress is present in porcelain, even in the absence of intra-oral forces. Fixed-partial-denture (FPD) specimens and semicircular arch specimens with gapped cross-arch segments were employed to characterize the potential of two incompatible metal-ceramic systems for producing delayed crack development and to determine the relative sensitivity of these test designs as monitors of incompatibility stresses which resulted from thermal contraction differences between a nickel-chromium alloy and three experimental porcelains. The arch specimens were judged to be more suitable for analysis of residual stresses because of the larger magnitude of gap changes at each procedural change. However, the FPD specimens exhibited earlier evidence of delayed crack growth in porcelain when the thermal contraction coefficient of the metal exceeded that of the porcelain by either 1.7 X 10(-6)/degrees C or 2.2 X 10(-6)/degrees C. For these two states of incompatibility, the agreement between experimental gap values for the arch specimens and the gap values predicted from composite strip equations was excellent.

Chemical Phenomena↗
PubMed1986

Presacral neurectomy for chronic pelvic pain.

Over an eight-year period, 50 presacral neurectomies were performed at Madigan Army Medical Center for chronic pelvic pain failing response to medical management. Each hospital record was reviewed and 45 patients answered a questionnaire grading the severity of their pain from 0 to 10 for dysmenorrhea, dyspareunia, and other pelvic pain before and after surgery. The results showed success rates of 73% in relieving dysmenorrhea, 77% in relieving dyspareunia, and 63% in relieving other pelvic pains. The addition of a bilateral uterosacral ligament resection to the presacral neurectomy did not increase the success rate. There was an 18% lateral pelvic pain recurrence rate, and no recurrence of dysmenorrhea. Complications occurred in 4%.

Adolescent↗