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Biomedical subjects

D O'Connor

Publications and source records attributed to D O'Connor.

At least 91 records · Page 5Linked to original sources
PubMed1994

Diagnosis of deep vein thrombosis in elderly hip-fracture patients by using the duplex scanning technique.

To detect the incidence of preoperative and postoperative deep vein thrombosis (DVT) in elderly patients with hip fracture, 100 patients aged 65 years and older with either a subcapital or intertrochanteric hip fracture were evaluated by duplex beta-mode ultrasonography. Treatment was based on each scan result: if evidence for DVT was seen, the patient was therapeutically anticoagulated; lacking signs of DVT, patients were treated prophylactically. Before their operation, 77 patients (77%) had normal results of their scans, while DVT was diagnosed in 12 patients (12%). An additional 11 patients (11%) developed DVT after the operation. The total incidence of DVT in this series was 23%.

Aged↗
PubMed1994

A comparison of the three most common Papanicolaou smear collection techniques.

OBJECTIVE: To evaluate three common instruments for sampling the endocervical canal: the Q-tip applicator, the Cytobrush, and the Cervex brush. METHODS: Clinical, cytologic, and histologic data were collected from patients enrolled in the colposcopy clinic at the National Naval Medical Center. Subjects were assigned to one of three techniques: a combination of spatula and swab, a combination of spatula and Cytobrush, and the Cervex brush alone. RESULTS: There was no significant difference in the ease of use or the amount of patient discomfort among the three methods, although the Cytobrush caused an increase in mild cervical bleeding. The Cytobrush yielded the greatest number of endocervical cells. The swab produced the lowest number of endocervical cells and the greatest cellular distortion. The ability to identify patients with biopsy-proven dysplasia was comparable for each of the three methods. CONCLUSION: The Cytobrush was the best device for sampling the endocervical canal, but it was no more sensitive in detecting cervical dysplasia.

Adult↗
PubMed1993

Management of advanced ovarian epithelial cancer in the renal transplant patient.

Stage IIIC, grade 1 papillary serous adenocarcinoma of the ovary was diagnosed in a 28-year-old renal transplant recipient. She had been treated with the immunosuppressive agents azathioprine and methylprednisolone for 7 years prior to the discovery of the ovarian cancer. Surgical excision of the tumor was suboptimal due to involvement of the allograft; however, the patient achieved a complete clinical response after eight courses of cisplatin and cyclophosphamide. Since multiagent immunosuppressant therapy may have contributed to the development of the ovarian carcinoma, the intensity of immunosuppression was decreased by discontinuing the azathioprine as soon as the diagnosis of ovarian cancer was made. The methylprednisolone, however, was continued to decrease the possibility of organ rejection. After completion of chemotherapy, the patient was started on a daily regimen of low-dose oral cyclophosphamide as an immunosuppressant. Four months following the completion of cytotoxic therapy, she developed clinically evident disease in the pelvis. Subsequent salvage therapy with carboplatin failed. The patient died from progressive disease 26 months after initial diagnosis. She never developed evidence of renal rejection. Combined modality cancer therapy, preservation of allograft function, and modification of immunosuppressant therapy are important goals in the renal transplant patient with advanced ovarian carcinoma.

Adult↗
PubMed1993

The contribution of the nonporous distal stem to the stability of proximally porous-coated canine femoral components.

The contribution of the distal nonporous-coated stem to the stability of the uncemented femoral components, which were porous coated only proximally, was investigated under two conditions: (1) immediately after insertion and (2) at 6 months, 1 year, and 2 years after surgery in a canine model. The relative motion of the femoral components at the bone porous-coating interface under loads simulating the canine midstance was measured at these time periods using displacement transducers. The measurements were repeated after severing the connection between the porous-coated proximal body and the nonporous-coated distal stem through a small hole in the anterior cortex. The results showed that while the distal nonporous-coated stem enhanced the immediate stability of the proximally porous-coated uncemented femoral components, it contributed little to the long-term stability of the femoral components after bony ingrowth had occurred in vivo. The mean relative motion between the body of the prosthesis and the cortical bone increased from 12 microns (+/- 7 microns) to 31 microns (+/- 34 microns) in the posterior transverse direction when the stem was immediately severed after the surgery. However, at 6 months, 1 year, and 2 years after surgery, extensive bone ingrowth had occurred into the proximal porous-coated regions of the body and provided excellent stability to the femoral components. With bone ingrowth, the mean relative motion was less than 5 microns at any site. Under these conditions, severing the stem did not increase the relative motion of the prostheses significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Alloys↗
PubMed1993

Impact of chronic stress hormone infusion on hepatic carbohydrate metabolism in the conscious dog.

The effects of chronic administration of counterregulatory hormones on hepatic glycogenolysis and gluconeogenesis were investigated. We studied 14 20-h fasted conscious dogs prior to (day 0) and after a 70-h stress hormone (SHI, n = 7) or saline (n = 7) infusion (day 3). Glucose production and gluconeogenesis were assessed using tracer and arteriovenous difference techniques. SHI increased plasma glucagon, cortisol, epinephrine, and norepinephrine levels approximately fivefold. SHI increased the arterial plasma glucose and insulin concentrations (110 +/- 2 to 204 +/- 19 mg/dl and 13 +/- 2 to 36 +/- 3 microU/ml on day 3). Tracer-determined glucose appearance and net hepatic glucose output were increased 80 and 60%, respectively. Net hepatic lactate uptake and fractional extraction were increased by 11.2 +/- 3.8 and 0.51 +/- 0.18 mumol.kg-1 x min-1, respectively, as was net hepatic glycerol uptake (1.0 +/- 0.6 mumol.kg-1 x min-1). Net hepatic fractional alanine extraction was also increased by 0.37 +/- 0.03 mumol.kg-1 x min-1; however, net hepatic alanine uptake was not altered. The efficiency of alanine conversion to glucose almost doubled (0.33 +/- 0.05 to 0.59 +/- 0.09). Renal glucose production was also increased, accounting for 33% of the increase in glucose turnover. This increase was paralleled by an increase in renal gluconeogenic precursor uptake. In conclusion, SHI created marked hyperglycemia and hyperinsulinemia and elevated glucose production from both the liver and the kidney, with gluconeogenesis accounting for approximately 70% of the response.

Animals↗
PubMed1993

Coenzyme Q10 with multiple vitamins is generally ineffective in treatment of mitochondrial disease.

We followed 16 patients with a variety of mitochondrial diseases over one to four periods of treatment (2 months each) with coenzyme Q10 plus vitamins K3 and C, riboflavin, thiamine, and niacin, using independent measures of oxidative metabolism to assess efficacy. There were large (> threefold) increases in serum coenzyme Q10 concentrations with treatment, but no measure of oxidative metabolism showed significant improvement with treatment for the group, nor did any individual patient show significant, reproducible, objective clinical improvement. The results suggest that coenzyme Q10 plus vitamin therapy does not significantly improve mitochondrial oxidative metabolism in patients with mitochondrial disease in general. Any clinical benefit that may follow from short-term administration appears slight.

Adenosine Triphosphate↗
PubMed1992

Clinical surveillance of gynecologic cancer patients.

A survey of gynecologic oncologists was used to determine the optimum follow-up plan for asymptomatic, disease-free patients previously treated for a gynecologic malignancy. Ninety-four (91%) of 103 questionnaires were completed and returned. The majority of respondents recommended a clinic visit for these patients every 3 months for the first year after the completion of therapy, every 3 or 4 months for the second year, every 6 months for the following 3 years, and then annually after this initial 5-year period. Breast, abdominal, lymph node, and pelvic examinations, as well as a pap smear and stool guaiac, were done at each of these clinic visits. A yearly chest X ray was performed by the majority of the survey respondents for the first 3 years following initial treatment. Determinations of serum CA-125 and ovarian germ cell tumor markers were done at each follow-up appointment during the first 5 years after therapy if they were previously elevated. The patients' smoking habits were discussed with them by the majority of respondents. Mammograms were performed periodically before age 50 and then yearly after age 50 by most respondents. Serum cholesterol determinations were accomplished every 5 years or more frequently if indicated. Calcium supplementation was recommended for postmenopausal patients. The majority of respondents did not recommend routine vitamin supplementation or surveillance sigmoidoscopy.

Ambulatory Care↗
PubMed1992

Quantification of implant micromotion, strain shielding, and bone resorption with porous-coated anatomic medullary locking femoral prostheses.

Fourteen femora containing porous-coated anatomic medullary locking (AML) femoral prostheses were retrieved from 12 patients at autopsy. Clinical roentgenograms in 13 femora showed bone remodeling changes, indicating that the implants were fixed by osseointegration. Under simulated physiologic loading, micromotion between the implant and the bone was measured using electrical displacement transducers connected to the implant and to the adjacent cortex. The micromotion between the implants at the areas of porous coating and the adjacent cortex in the one case of failed bone ingrowth measured 150 microns. Maximum relative motion between the cortex and the implant in the areas of porous coating for the 13 cases showing signs of bone ingrowth was 40 microns, and this was completely elastic relative displacement. With all implants, the micromotion between the cortex and the stem was always greatest over the uncoated portion of the stem. Four of the implants were proximally porous coated. With these, the micromotion was greater over the uncoated areas than with more extensively coated stems and was always greatest at the uncoated tip of the prosthesis. The amount of micromotion was directly related to the extent of porous coating on the implant. Maximum tip motion for the proximally coated implants was 210 micra, whereas for the fully porous-coated implants, it was 40 microns. In nine of the autopsies, the contralateral normal femur was obtained in addition to the femur containing the AML (the in vivo remodeled femur). These were used for comparative studies of strain shielding and femoral remodeling. Cortical strains were measured in the in vivo remodeled femora and were compared with measurements made in the contralateral normal femora before and following implantation of a stem identical to that present on the clinically treated side. The data showed major strain reductions in all the postmortem implanted normal femora. Comparison of the strain data from the postmortem implanted normal femora with those from the in vivo remodeled femora clearly indicated that extensive bone remodeling did not result in restoration of cortical strain levels anywhere near normal. Strain shielding continued to exist in all of the remodeled specimens, even up to 7.5 years after surgery. This strain shielding was associated with bone remodeling changes that resulted in regional reductions in bone mineral content that ranged from 7% to 78%. These observations are unique, important, and valuable in defining the in vivo function and clinical behavior of this type of porous-coated femoral component.

Aged↗
PubMed1992

Intestinal invasion by a dysgerminoma in a patient with Swyer syndrome.

An unusual case is presented of advanced dysgerminoma in a patient with Swyer syndrome, 46,XY pure gonadal dysgenesis. Unexpected regional invasion necessitated bowel resection, total abdominal hysterectomy, and bilateral salpingogonadectomy for a complete en bloc excision of the primary tumor mass and the dysgenetic gonads. This report illustrates the possible need for extensive operative resection in patients with Swyer syndrome.

Adnexa Uteri↗
PubMed1990

Metastatic placental site trophoblastic tumor.

A patient with metastatic placental site trophoblastic tumor is presented. Her treatment included several aggressive chemotherapeutic regimens. In this patient, the clinical course and assays of beta-hCG (beta fragment of human chorionic gonadotropin) correlated with her response to these treatments.

Adult↗
PubMed1990

Osseous metaplasia in ovarian papillary serous cystadenocarcinoma.

The finding of osseous metaplasia within an ovarian papillary serous cystadenocarcinoma is very rare. A review of the medical literature reveals only two previously published cases where mature bone was found in an ovarian serous cystadenocarcinoma. This report presents an additional case of this unusual phenomenon whose clinical significance remains uncertain.

Cystadenocarcinoma↗
PubMed1990

Noninvasive cardiac output: simultaneous comparison of two different methods with thermodilution.

The authors attempted to simultaneously measure cardiac output by thermodilution (COtd), thoracic bioimpedance (CObi), and suprasternal Doppler ultrasound (COdopp) in 68 patients. Subgroups separately compared included patients whose lungs were mechanically ventilated, patients undergoing cardiac surgery, aortic surgery, patients with dysrhythmias, and patients with sepsis. The authors also studied the value of the ventricular ejection time (VET) in evaluating the agreement of CObi and COdopp with COtd. Simultaneous CObi and COtd were available in a total of 56 patients (416 data sets) with an overall correlation coefficient r = 0.61, regression slope (m) of 0.52, intercept (y) of 2.46, and mean (CObi-COtd) difference (bias) of -0.67 +/- 1.72 (SD) l/min. Simultaneous COdopp and COtd were available in 59 patients (446 data sets) with an overall r = 0.51, m of 0.53, y of 2.05, and bias of -0.79 +/- 1.95 l/min. CObi agreed most closely with COtd in patients whose lungs were mechanically ventilated, who had not undergone cardiac or aortic surgery, and with VET difference less than 40 ms (16 patients, 99 data sets; r = 0.74; m = 0.97; y = 0.15; bias = -0.02 +/- 1.53 l/min). COdopp agreed most closely with COtd in patients whose lungs were mechanically ventilated, who had not undergone cardiac or aortic surgery, and in sinus rhythm with VET difference less than 40 ms (10 patients, 45 data sets; r = 0.82; m = 0.98; y = -0.07; bias = -0.82 +/-1.03 l/min). VET by radial artery can help evaluate the reliability of CObi and COdopp.

Aorta↗
PubMed1990

Characterization of the traT gene and mutants that increase outer membrane permeability from the Salmonella typhimurium virulence plasmid.

The nucleotide sequence of the traT gene present in the virulence-associated plasmid of Salmonella typhimurium was determined. The predicted TraT protein encoded by this gene was found to consist of 243 amino acids and to resemble the known TraT proteins of the plasmids of the F incompatibility group. Thus it contains a signal sequence of 20 amino acids, an amino-terminal lipid attachment site, and two strongly hydrophobic regions close to each other in the mature protein. A mutation leading to increased permeability of the outer membrane to hydrophobic agents, previously localized to the traT gene, was shown to change a glycine residue to arginine within one of these hydrophobic regions. The same principle was found to apply to TraT of R6-5: the introduction, by site-directed mutagenesis, of either positively or negatively charged amino acids or the helix-disrupting proline in the corresponding hydrophobic region led to increased hydrophobic permeability of the outer membrane.

Amino Acid Sequence↗