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Biomedical subjects

E Ellis

Publications and source records attributed to E Ellis.

At least 55 records · Page 3Linked to original sources
PubMed1999

Treatment methods for fractures of the mandibular angle.

Fractures of the mandibular angle are plagued with the highest rate of complication of all mandibular fractures. Over the past 10 years, various forms of treatment for these fractures were performed on an indigent inner city population. Treatment included: 1) closed reduction or intraoral open reduction and non-rigid fixation; 2) extraoral open reduction and internal fixation with an AO/ASIF reconstruction bone plate; 3) intraoral open reduction and internal fixation using a solitary lag screw; 4) intraoral open reduction and internal fixation using two 2.0 mm mini-dynamic compression plates; 5) intraoral open reduction and internal fixation using two 2.4 mm mandibular dynamic compression plates; 6) intraoral open reduction and internal fixation using two non-compression miniplates; 7) intraoral open reduction and internal fixation using a single non-compression miniplate; and 8) intraoral open reduction and internal fixation using a single malleable non-compression miniplate. This paper reviews the results of those modes of treatment when used for the same patient population at one hospital. Results of treatment show that, in this patient population, the use of either an extraoral open reduction and internal fixation with the AO/ASIF reconstruction plate or intraoral open reduction and internal fixation, using a single miniplate, are associated with the fewest complications.

Adult↗
PubMed1998

Bile acid synthesis in primary cultures of rat and human hepatocytes.

The regulation of hepatic bile acid formation is incompletely understood. Primary cultures of mammalian hepatocytes offer an opportunity to examine putative regulatory factors in relative isolation. Using rat and human hepatocytes in primary culture, we examined bile acid composition and the expression of the rate-limiting enzyme of formation, cholesterol 7alpha-hydroxylase. Control rat hepatocytes showed a declining bile acid production over 4 days, from 156 +/- 24 ng/mL (67% cholic acid) on day 1 to 55 +/- 11 ng/mL (55% cholic acid) on day 4. In addition to cholic acid, chenodeoxycholic acid, alpha-muricholic acid, and beta-muricholic acid were formed. Treatment with triidothyronine (T3) or dexamethasone alone had no significant effect on bile acid production. A combination of T3 and dexamethasone significantly increased the total bile acid production on day 4 (224 +/- 54 ng/mL) and resulted in a marked change in composition to 23% cholic acid and 77% non-12alpha-hydroxylated bile acids. Control rat hepatocytes had a cholesterol 7alpha-hydroxylase activity of 3.3 +/- 0.6 pmol/mg protein/min after 4 days in culture. Cells treated with the combination of dexamethasone and T3 had an activity of 16.4 +/- 3.6 pmol/mg protein/min. The cholesterol 7alpha-hydroxylase messenger RNA (mRNA) levels, determined by solution hybridization after 4 days of culture, showed results similar to those for the activity data; control cells had 5.3 +/- 0.9 cpm/microg total nucleic acids (tNAs). T3 or dexamethasone-treated cells did not differ from control cells, whereas the combination of T3 and dexamethasone increased the mRNA levels to 20.6 +/- 2.8 cpm/microg tNAs. In human hepatocytes, isolated from donor liver, bile acid formation increased from 206 +/- 79 ng/mL on day 2 to 1490 +/- 594 ng/mL on day 6 and then declined slightly. Cholic acid and chenodeoxycholic acid were formed, constituting about 80% and 20%, respectively. The combined addition of T3 and dexamethasone had a tendency to decrease rather than increase bile acid formation. Also, mRNA levels of the cholesterol 7alpha-hydroxylase increased severalfold in the human hepatocytes from day 2 to day 4 and then declined. The addition of T3 or dexamethasone did not effect the mRNA levels in any consistent way. It is noteworthy that the capacity of the cultured human hepatocytes to produce bile acids was higher than that of cultured rat hepatocytes, in spite of the fact that the production of bile acids in rat liver is 3- to 5-fold higher than that in human liver in vivo. It is also evident that while hormonal factors appear to regulate bile acid synthesis in the rat, no evidence for this was found in human hepatocytes. As the composition of bile acids secreted by human hepatocytes in primary culture closely resembles that found in vivo, this represents a useful model for further studies of the synthesis and regulation of bile acids.

Adolescent↗
PubMed1998

Breathing patterns and heart rate during simulated occupational upper limb tasks in normal subjects.

BACKGROUND AND PURPOSE: Despite the arms being used extensively in the performance of many occupational tasks, little is known about the pattern of breathing and physiological cost of such work. The purpose of this study was to establish whether a simple change in arm support could alter the workload, pattern of breathing and respiratory muscle recruitment during a low intensity arm task. METHODS: Ten normal subjects performed a simulated work task when sitting, once with the arms supported and once unsupported. Subjects were required, over a five-minute period, to repeatedly pick up a 2 kg object, inspect and hold it for 15 seconds and then pack it in a box. Breathing pattern responses, measured by pneumotachograph and respiratory inductive plethysmography, were minute ventilation (VE), respiratory frequency (Rf), tidal volume (VT) and change in functional residual capacity (FRC). RESULTS: The main findings were that unsupported arm work was more physiologically demanding than supported arm work. During work VE increased as a result of a change in respiratory frequency but not VT which was much more limited when the arms were unsupported. At the completion of activity, when the arms were unloaded, VT initially increased as VE decreased. FRC and VT were reduced during arm work and increased during recovery, mainly as a result of a change in ribcage excursion. CONCLUSIONS: These findings support the theory that during arms activity, intercostal and accessory respiratory muscles act to stabilize the arms and torso, impeding chest wall movement and shifting the respiratory load from these muscles to the diaphragm. This may adversely effect performance of workers who have ventilatory limits to arm work tasks.

Adolescent↗
PubMed1998

Use of a locking reconstruction bone plate/screw system for mandibular surgery.

PURPOSE: This study examined the use of a locking reconstruction bone plate/screw system for use in mandibular surgery. PATIENTS AND METHODS: All patients treated with a locking reconstruction bone plate/screw system for fractures of the mandible or continuity defects in an 18-month period were prospectively studied. Ease of use of the locking plate/screw system, characteristics of the fractures/defects, and complications were tabulated. RESULTS: One hundred two locking bone plates were placed in 84 patients. Most patients (n=75) were treated for fractures of the mandible; there were eight continuity defects and one case of mandibular narrowing. There were no cases of malocclusion or difficulties encountered in using the plate/screw system. Loss of fixation was encountered in only one patient. CONCLUSIONS: The use of a locking plate/screw system was found to be simple, and it offers advantages over conventional bone plates by not requiring the plate to be compressed to the bone to provide stability.

Adolescent↗
PubMed1998

Adaptations of the masticatory system after bilateral fractures of the mandibular condylar process.

PURPOSE: The objective of this investigation was to evaluate the adaptations that occur in the masticatory system after treatment of bilateral fractures of the mandibular condylar process. PATIENTS AND METHODS: Twenty-two patients (15 men and seven women) with bilateral condylar process fractures treated by open reduction and rigid internal fixation (n = 6), closed therapy (n = 14), or a combination of these techniques (n = 2) were compared with 22 sex- and age-matched controls. Measures of mandibular range of motion, bite force, muscle activity, estimated joint forces, and skeletal morphology were determined at 6 weeks, 6 months, and 1, 2, and 3 years after treatment in all subjects. Various statistical tests were used for comparing differences between patients and controls. RESULTS: There was no significant difference in the patients' morphologic measures for the open and closed reduction procedures; therefore, all of these patients were tested as a single group. After treatment, patients had significantly increased mandibular plane and gonial angles and decreased facial axis angles. They also showed a significant reduction in posterior facial height and moment arm length for the masseter and pterygoid muscles. Anterior and posterior temporalis muscle direction also was significantly different between patients and controls. Patients had significantly limited mobility during the first year after fracture. Bite forces were lower for patients at all times and tooth positions, with a significant difference at 6 weeks after treatment. Patients had a tendency to use proportionally higher temporalis muscle activity during maximum biting; however, the differences were not statistically significant, probably because of the small sample size. The estimated joint force magnitudes were essentially identical between patients and controls; however, the direction of the patients' joint forces were more posteriorly directed for both incisor and molar bites. CONCLUSION: The results of this study suggest that early reduction in mandibular range of motion, bite force, and the distribution of masticatory muscle activity assist in preventing overloading of the bilaterally fractured mandibular condylar processes.

Adaptation, Physiological↗
PubMed1998

A randomised placebo controlled trial of suppressive acyclovir in late pregnancy in women with recurrent genital herpes infection.

OBJECTIVE: To evaluate the efficacy and safety of a suppressive course of acyclovir in late pregnancy in women with recurrent genital herpes infection on the incidence of viral shedding, herpes lesion development and caesarean section for recurrent genital herpes. DESIGN: Double-blind, randomised placebo controlled clinical trial. SETTING: A department of genitourinary medicine in Sheffield and an antenatal clinic in London. POPULATION: Pregnant women with recurrent genital herpes infection at < 36 weeks of gestation. METHODS: Participating women were given acyclovir 200 mg four times a day (or matching placebo) from 36 weeks of gestation until the time of delivery. Women were seen weekly and viral cultures were obtained from the cervix and vulva. Decisions regarding mode of delivery were left to the discretion of the attending obstetrician. MAIN OUTCOME MEASURES: Delivery by caesarean section for recurrent genital herpes infection. Number of episodes of recurrent genital herpes infection and number of episodes of asymptomatic viral shedding during the treatment period. In addition blood was taken at two weekly intervals to determine acyclovir levels. RESULTS: The total number of women recruited was 63 (31 received acyclovir and 32 received placebo). The number of women undergoing delivery by caesarean section for recurrent herpes at the time of delivery was 12 (19%). The odds ratio for delivery by caesarean section in women taking acyclovir, compared with those taking placebo, was 0.44 (95% CI 0.09-1.59). The odds ratio for clinical recurrences during treatment was 0.10 (95% confidence interval 0.00-0.86) and the odds ratio for clinical recurrence or asymptomatic shedding during treatment was 0.32 (95% CI 0.05-1.56). CONCLUSION: This trial was unable to demonstrate that acyclovir can significantly decrease the number of caesarean section deliveries; however, the number of clinical recurrences was significantly reduced. Two episodes of asymptomatic virus shedding both occurred in women taking acyclovir. At the present time there is little evidence to suggest that acyclovir should be used outside randomised controlled trials for the suppression of recurrent genital herpes infection during pregnancy.

Acyclovir↗
PubMed1998

Predicting chronicity in acute temporomandibular joint disorders using the research diagnostic criteria.

The authors describe a prospective study designed to examine the clinical utility of the Research Diagnostic Criteria for Temporomandibular Disorders, or RDC/TMD, in evaluating physical and psychological differences between patients with acute TMD that does not become chronic and patients with chronic TMD. A total of 153 patients with acute TMD participated in the study; the researchers deemed the condition of 87 of these patients to be chronic after a six-month follow-up period, and that of 66 patients to be nonchronic. Using a multiple logistic regression model, the authors found that a number of physical and psychological variables differed significantly between the two groups. These results highlight the importance of the physical-psychosocial interface that affects the development of chronic TMD.

Acute Disease↗
PubMed1997

Cytomegalovirus infections following renal transplantation--effects on antiviral prophylaxis: a report of the North American Pediatric Renal Transplant Cooperative Study.

Post-transplant cytomegalovirus (CMV) infections are a source of significant morbidity. However, the extent of the problem and the benefits of various antiviral prophylactic therapies remain incompletely understood. The North American Pediatric Renal Transplant Cooperative Study registry was screened to identify patients hospitalized for CMV infections during the 1st post-renal transplant year between 1987 and 1993. Using a control group of transplant recipients, we performed a retrospective analysis of risk factors for CMV disease among these hospitalized patients and studied the effects of various viral prophylactic strategies on CMV risk, clinical manifestations, and outcome. We identified 142 patients hospitalized with CMV infections, the majority of which included major organ involvement. A CMV-positive kidney donor was the most significant risk factor for hospitalization [odds ratio (OR) = 5.2, P<0.0001] irrespective of recipient age or CMV immune status. As opposed to antiviral agents (acyclovir, ganciclovir) or pooled IgG, prophylaxis with enriched anti-CMV IgG significantly reduced the risk of CMV hospitalization (OR = 0.31, P = 0.03). The prophylactic use of antiviral agents was associated with a decreased risk of major organ involvement during the CMV infection (OR = 0.34, P<0.005). Among the patients with CMV, the 3-year graft survival was significantly better for those who received any form of prophylaxis compared with those who received none (88% vs. 52%, P<0.001). Our findings suggest a role for combined CMV-enriched IgG and antiviral agent prophylaxis for post-transplant CMV disease. Such an approach could diminish the incidence and severity of CMV infection and appears to have an independent favorable effect on graft outcome.

Adolescent↗
PubMed1997

Comparison of habitual masticatory patterns in men and women using a custom computer program.

STATEMENT OF PROBLEM: Though computer-based systems for recording three-dimensional jaw motion and muscle activity during mastication are common, few computer programs are available to analyze the resultant data. Few studies have discussed the variability over time of the many parameters of the masticatory cycle now measurable by computer systems. PURPOSE: The purposes of this study were to (1) use a custom computer program, (MAS), for analysis of long-term repeated measurements of mandibular motion and muscle activity; (2) determine sex differences for mandibular movements and activity of the muscles involved during mastication; and (3) determine the variability over time and the statistical power of these methods. MATERIALS AND METHODS: Masticatory cycles of 20 normal men and 17 normal women were examined during mastication of a constant bolus at a sampling rate of 500 fps. Measurements included duration of chewing cycle and its component phases, mandibular displacement in three dimensions, and electromyographic activity in the temporalis and masseter muscles. The MAS custom computer program was used for analysis. Two-way repeated measures analysis of variance was used to compare the men with the women over three trials at 0, 6, and 12 months. The variability over time associated with each measurement was also estimated. RESULTS: Timing of the phases of the chewing cycle were most repeatable between trials, whereas lateral excursions and muscle force magnitudes were the least repeatable measures. Durations of total cycle, its slow-open and fast-close phases, were significantly longer for the female group, and their bursts of muscle activity tended to be longer. The amount of vertical mandibular excursion tended to be greater for men. There were no gender-related differences in the amplitude of muscle activity. CONCLUSIONS: This study demonstrated that men have significantly shorter chewing cycles with faster velocities than women. Men used significantly greater chewing force than women, although their electromyographic activity levels were equivalent. The masticatory measurements made by the MAS program had differing amounts of variation over time. Total duration of the chewing cycle and amount of opening varied the least, whereas amount of lateral excursion and jaw muscle electromyographic magnitudes exhibited the greatest variation.

Adult↗
PubMed1997

Functional and morphologic alterations after anterior or inferior repositioning of the maxilla.

PURPOSE: The purpose of this investigation was 1) to compare functional and morphologic measurements between controls and patients scheduled for anterior or inferior repositioning of the maxilla, and 2) to examine how these patients' oral function adapted after surgery. PATIENTS AND METHODS: Nine male patients undergoing anterior and/or inferior repositioning of the maxilla were compared with 26 male controls preoperatively and up to 3 years after surgery. Measures of skeletal morphology, mandibular range of motion, maximum voluntary bite force, and levels of electromyographic (EMG) activity in the anterior and posterior temporalis and masseter muscles during isometric bites were made on all subjects over time. One-way ANOVA was used to compare the controls, the patients before surgery, and the patients after surgery. RESULTS: Before surgery, most of the patients had morphologic characteristics of mandibular prognathism and maxillary retrognathism. Surgery made the patients' skeletal morphology similar to controls except for mandibular length, upper facial height, and palatal plane angle, which were significantly greater than those of controls. There were no significant differences in jaw muscle mechanical advantage between controls and patients either before or after surgery. Hypomobility of the jaw was apparent at 6 weeks and 6 months after surgery, but returned to normal values within 1 to 2 years. Before surgery, the patients had maximum voluntary bite forces significantly less than those of controls. Bite forces in patients steadily increased after surgery, approaching significantly higher values than those of controls. Before surgery, patients' muscle activity levels per unit of bite force were not significantly different from those of controls. Most of the patients' muscle activity levels per unit of bite forces at all bite positions showed no significant change after surgery. CONCLUSIONS: The results of this study suggest that anterior or inferior repositioning of maxilla produces some significant functional benefits in patients.

Adult↗
PubMed1997

Comparison of habitual masticatory cycles and muscle activity before and after orthognathic surgery.

PURPOSE: The purpose of this investigation was to study the long-term effects of orthognathic surgery on mastication in patients before and after four surgical procedures: mandibular advancement, maxillary intrusion, maxillary intrusion with mandibular advancement, and maxillary inferior repositioning. MATERIALS AND METHODS: The components and timing of mandibular motion, electromyography (EMG), and estimated biting forces during mastication were studied in 61 patients who underwent orthognathic surgery for correction of four different deformities. The data were statistically compared with 38 control subjects using ANOVA. RESULTS: Preoperatively, there were no significant differences in the duration of the chewing cycles and mandibular excursions among the groups, nor did surgery have any affect on these variables. Before surgery, estimated occlusal forces in the patient groups were smaller than controls. Although these appeared to increase after surgery, the increases did not exceed changes in our untreated controls. CONCLUSIONS: The results of this study suggest that, with the exception of EMG and occlusal forces, mastication in orthognathic surgery patients is not significantly different from controls either before or after surgery. EMG during mastication, although significantly lower than in controls before surgery, showed significant increases after surgery, but these increases did not bring estimated occlusal forces up to control levels.

Adaptation, Physiological↗
PubMed1997

High-dose busulfan, melphalan, thiotepa and peripheral blood stem cell infusion for the treatment of metastatic breast cancer.

The purpose of this study was to determine the outcome of patients with metastatic breast cancer treated with high-dose busulfan (Bu), melphalan (Mel) and thiotepa (TT) followed by peripheral blood stem cell (PBSC) infusion. Fifty-one patients with chemotherapy refractory (n = 32) or responsive (n = 19) metastatic breast cancer received Bu (12 mg/kg), Mel (100 mg/m2) and TT (500 mg/m2) followed by PBSC collected after chemotherapy and growth factor (n = 43) or growth factor alone (n = 8). The 100 day treatment-related mortality was 8% including one death from cytomegalovirus pneumonia, one from aspiration pneumonia and two from regimen-related toxicity (RRT). Seven of 28 refractory (25%) and 5/7 (71%) responsive patients with evaluable disease achieved a complete response of all measurable disease or all soft tissue disease with at least improvement in bone lesions (PR*). Fifteen of 51 patients (29%) are alive and progression-free a median of 423 days (range 353-934) after treatment, 5/32 (16%) with refractory disease and 10/19 (53%) with responsive disease. The probabilities of progression-free survival (PFS) at 1.5 years for the patients with refractory (n = 32) and responsive (n = 19) disease were 0.24 and 0.53, respectively. These preliminary data suggest that high-dose Bu/Mel/TT has significant activity in patients with advanced breast cancer and may be superior to some previously published regimens.

Adult↗
PubMed1997

Lag screw fixation of mandibular fractures.

The lag screw is the simplest means of rigid internal fixation. By virtue of its ability to compress bone fragments without the use of a bone plate, it has wide application and achieves great stability. This article presents techniques to apply lag screws to fractures of the mandibular symphysis, the mandibular body, and the mandibular angle. Results are reviewed in studies of 315 patients whom the author has treated with lag screw fixation. The advantages of the lag screw technique over bone-plate fixation, such as a more rapid application, obviation of the need to adapt a bone plate, minimal displacement of bone segments, and the rapid application of fixation without diminishing the rigidity of the fracture reduction, are discussed, as are the technique's contraindications.

Bone Plates↗