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Biomedical subjects

D Hayes

Publications and source records attributed to D Hayes.

At least 19 recordsLinked to original sources

Feasibility of using intracardiac impedance measurements for capture detection.

Energy consumption and longevity of modern pacemakers are determined by the controlling electronic circuitry and by the stimulation energy. While with technological progress the electronics' energy consumption has been reduced significantly, clinical practice shows that many cardiac pacemakers are programmed to suboptimal settings with regard to minimization of pacing energy consumption. Several methods for optimizing pacemaker output settings have been proposed in the past. The most promising concept is an output parameter optimizing pacemaker with automatic capture detection. We examined whether it is possible to distinguish between effective and ineffective pacemaker stimulus capture by analyzing high pass filtered intracardiac impedance signals that are derived from standard bipolar pacing leads. In one series of 11 patients undergoing replacement or implantation of chronic bipolar pacemakers, four patients during electrophysiology studies, and eight volunteers undergoing invasive electrophysiology trials, we examined intracardiac impedance signals obtained with various stimulation rates and output parameter settings. Additionally we analyzed a series of five patients with implanted pacemakers that can measure and telemeter intracardiac impedance signals. Several evaluation concepts have been analyzed regarding their ability to discriminate between effective and ineffective stimuli. We developed an adequate algorithm that detects capture or loss of capture at different output parameter settings based on intracardiac impedance analysis. The sensitivity is 98.5% and specificity is 91% to loss of capture for the currently investigated algorithm and this can be used to determine the optimal setting of pulse width and amplitude with regard to energy consumption. This concept is currently under realization in the external programmer and in the future an implementation of these algorithms within the pacemaker itself is intended.

Algorithms

Salvage of hemodialysis access in infected arteriovenous fistulas.

Infection combined with additional complications of arteriovenous fistulas is a serious threat to access in patients with upper-extremity polytef (polytetrafluoroethylene) grafts. We present three cases of infected access grafts that were treated with systemic antibiotics, excision of the grafts, and primary anastomosis of the arterialized vein to artery for access salvage. The new arteriovenous fistulas were used immediately, preventing interruptions in hemodialysis regimens. This technique of immediate reconstruction allows the surgeon to utilize the arterialized outflow vein and save other sites of access for future use.

Aged

Cosmetic results after surgery, chemotherapy, and radiation therapy for early breast cancer.

Adjuvant chemotherapy (CT) is increasingly being used in conjunction with radiation therapy (RT) in the treatment of early stage breast cancer. To assess the effect of CT on the cosmetic outcome of the irradiated breast, we retrospectively reviewed the cosmetic results of patients who received either cyclophosphamide-methotrexate-fluorouracil (CMF) or doxorubicin-based chemotherapy in conjunction with breast irradiation between 1968 and 1985. The overall cosmetic results were evaluated by the physician as "excellent," "good," "fair," or "poor" using a standardized scale. The CT group consisted of 170 patients treated with CT and RT administered either concurrently or sequentially (CT before RT, after RT, or both) with a minimum of 24 months of cosmetic follow-up. These were compared to an RT alone control group of 170 patients who did not receive CT and were matched by tumor size, radiation technique, and year of treatment. At 36 months, the cosmetic scores for the CT group compared to RT alone were 47% versus 71% excellent (p less than 0.01), 36% versus 19% good, and 17% versus 9% fair or poor. For the 50 patients treated with concurrent CMF and RT, the scores were 31% excellent, 45% good, and 24% fair/poor, whereas for the 118 patients treated with sequential RT and CT they were 54%, 31%, and 14%, respectively. There was no difference between those patients who received sequential CMF and those treated with doxorubicin. We conclude that adjuvant chemotherapy adversely affects the cosmetic outcome of breast irradiation, but that this effect is not clinically significant unless CMF is administered concurrently with RT. Patients treated with either sequential CMF or doxorubicin-based CT had only a slight decrement in their cosmetic result compared to patients treated without CT.

Antineoplastic Combined Chemotherapy Protocols

Pseudosarcomatous lesions of the urinary bladder.

The clinical, microscopical, immunocytochemical and ultrastructural features of five cases of benign mesenchymal proliferative lesions of the urinary bladder, mimicking sarcoma, are presented. Four of the five patients are alive and disease-free following diagnosis, an interval ranging from 9 months to 9 years, mean 4 years. A fifth patient, who had a pseudosarcomatous stromal response adjacent to a urinary transitional cell carcinoma, now has invasive transitional cell carcinoma. The lesions revealed a striking microscopical, immunocytochemical and ultrastructural similarity to nodular fasciitis, suggesting the lesions represented a bizarre mesenchymal proliferative response to inflammation.

Adult

Separation of rat pituitary secretory granules by continuous flow electrophoresis.

The separation of growth hormone-containing cytoplasmic secretory granules from the rat pituitary gland by continuous flow electrophoresis is described. The results are consistent with the hypothesis that granule subpopulations can be separated due to differences in surface charge; these, in turn, may be related to the oligomeric state of the hormone.

Animals

Combined epidural and general anesthesia for abdominal aortic surgery.

The hypothesis that combined epidural and light general anesthesia for infrarenal abdominal aortic surgery is associated with a more stable intraoperative course and less postoperative morbidity than general anesthesia alone was tested. The authors compared intraoperative hemodynamic variables and postoperative morbidity between a group with combined epidural and general anesthesia (n = 30) and a group with general anesthesia (n = 19). Patients who had combined epidural and general anesthesia were given epidural bupivacaine intraoperatively and epidural morphine postoperatively. After cross-clamping of the aorta, cardiac index and pulmonary capillary wedge pressure did not change in the group with combined epidural and general anesthesia, whereas cardiac index decreased (mean change, 0.30 L/min/m2; P = 0.0006) and pulmonary capillary wedge pressure increased (mean change, 1 mm Hg; P = 0.007) in the group with general anesthesia. After unclamping, cardiac index increased in both groups (mean change, 0.26 L/min/m2, P = 0.002, and 0.30 L/min/m2, P = 0.001, respectively). Postoperatively, the necessity for ventilatory support and the incidence of respiratory failure were lower in the combined epidural and general anesthesia group than in the general anesthesia group (P = 0.0002 and P = 0.018, respectively). In addition, vasodilator therapy was required less frequently in the group with combined epidural and general anesthesia (P = 0.002). Duration of intensive care unit stay was shorter in the combined epidural and general anesthesia group (2.7 days v 3.8 days, P = 0.003). These data indicate that for infrarenal abdominal aortic surgery, combined epidural and general anesthesia is associated with more stable intraoperative hemodynamics and significantly less postoperative morbidity than general anesthesia alone.

Adult

An investigation of vanishing bone disease.

Vanishing bone disease is a rare condition producing local deformity and instability. Fibrovascular tissue replaces bone completely but the mechanism of bone destruction and resorption is unknown and there is controversy regarding the presence or absence of osteoclasts in the disease. Radiography, clinical chemistry, light microscopy, transmission electron microscopy (TEM) and cytochemistry were used to investigate the condition of a young woman presenting early in the disease process. We detected atypical ultrastructure in osteoblasts and endothelial cells. The rare osteoclasts, numerous mononuclear phagocytes and vascular endothelium found in the condition reacted positively for the enzyme acid phosphatase. Aggressive local excision of diseased tissue and insertion of a free vascularized bone graft at an advanced stage of the disease, accompanied by subsequent radiotherapy for residual disease only were successful in rehabilitating the affected forearm and hand.

Adult

Tartrate resistant acid phosphatase positive splenic lymphoma: a relatively benign condition occurring in a time-space cluster?

Conventional light and electron microscopic studies, together with cytochemical and immunocytochemical staining procedures, were carried out to ascertain whether the lymphomata of four elderly female patients living within 10 kilometers of each other, who presented within a short space of time with massive splenomegaly and varying cytopenia, belonged to any particular subgroup of lymphoma. In each case the lymphoma had a diffuse pattern and mature B cell phenotype. The malignant cells were of uniform cell type, slightly larger than admixed polymorphonuclear leucocytes, and showed minimal nuclear irregularity and positivity for tartrate resistant acid phosphatase (TRAP) staining. Their clinical and morphological features were compared with those of other lymphoproliferative disorders, but while sharing some features in common with each condition, this small group of patients seemed to have a unique combination of findings. The cytopenias of all four responded well after removal of the spleen and their disease has not been aggressive. It is concluded that these patients have a distinct subgroup of lymphoma, which it is important to recognise so that inappropriate use of aggressive cytotoxic drugs can be avoided.

Acid Phosphatase

Teaching first-year students the interpersonal recall process for patient interviews.

The authors investigated how well 52 internal medical residents understood the four modes of the interpersonal process recall (IPR) system after the students had received training in this system, and also investigated whether the students taught by instructors trained in the IPR system had a greater understanding of the system than those taught by nontrained instructors. Students were tested before and after the course, which involved extensive use of videotapes of interviews. With some reservations, the data as a whole suggest that the IPR system can be taught effectively by an enhancement of the methods used for this study and that the instructors do not have to receive training in the system to teach it effectively.

Humans

Acute effects of carbon monoxide exposure on individuals with coronary artery disease.

The purpose of this study was to determine, using more objective evidence than that reported in previous studies, whether or not exposures to carbon monoxide that produce approximately 2% or 4% blood carboxyhemoglobin levels cause an exacerbation of myocardial ischemia during a progressive exercise test. The objective measurements were based on the development of electrocardiographic evidence of ischemia. In addition, time to onset of angina pectoris was studied. Male subjects, ages 35 to 75, with stable exertional angina pectoris and positive exercise treadmill tests with reproducible ischemic ST-segment changes in their electrocardiograms, were studied. In addition, each subject fulfilled at least one of the following criteria of coronary artery disease: angiographic evidence of at least a 70% occlusion of one or more major coronary artery; prior documented myocardial infarction; or a positive exercise thallium test. Each subject was evaluated on four separate occasions, a qualifying visit and three blinded test visits, which involved exposure (in random order) to air without added carbon monoxide and to air that contained carbon monoxide concentrations calculated to produce approximately 2.2% or 4.4% carboxyhemoglobin, measured by gas chromatography, at the end of the exposure period. These immediate postexposure target levels were set 10% higher than the desired postexercise carboxyhemoglobin levels of 2.0% and 4.0% because exercise while breathing room air results in loss of carbon monoxide. The actual one-minute postexercise levels reached were 2.0% +/- 0.1% (mean +/- standard error of the mean) and 3.9% +/- 0.1%. On each test day, the subject performed a symptom-limited exercise test on a treadmill, was exposed for approximately one hour to air or to one of two levels of carbon monoxide in air, and then performed a second exercise test. Time to the onset of ischemic ST-segment changes and time to the onset of angina were determined for each exercise test. The percent difference for these endpoints on the pre- and postexposure exercise tests was determined, and then the results on the 2%-COHb-target day and the results on the 4%-COHb-target day were compared to those on the control day. Data from the 63 subjects who completed the three test visits and met all protocol criteria were analyzed. There were 5.1% (p = 0.01) and 12.1% (p less than or equal to 0.0001) (trimmed mean) decreases in the time to development of ischemic ST-segment changes after the 2%- and 4%-COHb-target exposures, respectively, compared to the control day.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult

Isolation and sequencing of a cDNA coding for the human DF3 breast carcinoma-associated antigen.

The murine monoclonal antibody (mAb) DF3 reacts with a high molecular weight glycoprotein detectable in human breast carcinomas. DF3 antigen expression correlates with human breast tumor differentiation, and the detection of a cross-reactive species in human milk has suggested that this antigen might be useful as a marker of differentiated mammary epithelium. To further characterize DF3 antigen expression, we have isolated a cDNA clone from a lambda gt11 library by screening with mAb DF3. The results demonstrate that this 309-base-pair cDNA, designated pDF9.3, codes for the DF3 epitope. Southern blot analyses of EcoRI-digested DNAs from six human tumor cell lines with 32P-labeled pDF9.3 have revealed a restriction fragment length polymorphism. Variations in size of the alleles detected by pDF9.3 were also identified in Pst I, but not in HindIII, DNA digests. Furthermore, hybridization of 32P-labeled pDF9.3 with total cellular RNA from each of these cell lines demonstrated either one or two transcripts that varied from 4.1 to 7.1 kilobases in size. The presence of differently sized transcripts detected by pDF9.3 was also found to correspond with the polymorphic expression of DF3 glycoproteins. Nucleotide sequence analysis of pDF9.3 has revealed a highly conserved (G + C)-rich 60-base-pair tandem repeat. These findings suggest that the variation in size of alleles coding for the polymorphic DF3 glycoprotein may represent different numbers of repeats.

Antibodies, Monoclonal

Exercise and psychologic well-being in the community.

In a representative sample of 401 adults in Illinois in 1984, the authors found that increased participation in exercise, sports, and physical activities is associated with improved psychologic well-being. Part of this association is through improved subjective physical health. The authors controlled for potentially confounding factors, including sociodemographic characteristics, instrumentalism, and overweight. They concluded that exercise is associated with decreased symptoms of depression (feelings that life is not worthwhile, low spirits, etc.), anxiety (restlessness, tension, etc.), and malaise (rundown feeling, trouble sleeping, etc.) in the general population, most of which is not severely depressed, and in which many persons are engaged in moderate, nonaerobic exercise.

Adolescent

Chronic eosinophilic pneumonia (Carrington's) with increased serum IgE levels. A distinct subset?

We report our second case of chronic eosinophilic pneumonia (CEP) (Carrington's pneumonia) with elevated serum IgE values and present a review of the literature on this subject. Our present patient, a 55-year-old woman, had classic symptoms of dry cough, weight loss, malaise, dyspnea, night sweats, and fevers. Significant peripheral blood eosinophilia and a right upper lobe infiltrate were present. Glucocorticoid therapy caused prompt resolution of symptoms, as well as disappearance of blood eosinophilia, elevated serum IgE levels, and pulmonary shadowing. The diagnosis of CEP should not be neglected in the classification of the eosinophilic pneumonias with increased serum IgE levels. The increased serum IgE levels, when present in CEP, seem nonspecific and thus may not be useful as a diagnostic adjunct. However, measurement of IgE may be helpful in CEP, as it has been in allergic bronchopulmonary aspergillosis, to guide the dosage and duration of corticosteroid therapy.

Female

Elevated pulmonary artery systolic storage volume associated with redistribution of pulmonary perfusion.

The possibility that an increased pulmonary arterial systolic storage volume (PASSV) correlates with a significant redistribution of pulmonary perfusion was examined in 30 surgical patients. Right ventricular stroke work index (RVSWI) was used as an index of distribution of pulmonary perfusion. The systolic storage volume was calculated from the pulmonary arterial compliance and mean pulmonary arterial distending pressure. Pulmonary arteriolar pressures were computed by Fourier analysis. Pulmonary arterial compliance was derived from the pulmonary arterial time constant and pulmonary arterial resistance. There was a linear relationship between PASSV and RVSWI (r = .81, p less than .001). Also, a direct correlation was found between RVSWI and pulmonary arterial time constant (r = .45, p less than .01). When the patients were divided into three groups according to the severity of pre-existing disease, linear relationships between PASSV and RVSWI were present in all groups, and the slopes were not different among the three groups. The patients were also divided into two groups based on a storage volume fraction of stroke volume index, to evaluate the effect of other hemodynamic data on the PASSV. Comparison of the two groups revealed that pulmonary arterial pressure and pulmonary arterial compliance were significantly higher in the group with a high storage volume fraction (p = .05 and p = .01, respectively). RVSWI and time constant were also significantly different between the groups (p less than .01 and p less than .01, respectively). We conclude that the pressure work generated by the right ventricle improved the distribution of pulmonary perfusion by increasing PASSV.

Capillary Permeability

Chondrosarcoma developing in synovial chondromatosis. A case report.

Synovial chondromatosis is a rare condition in which osteocartilaginous nodules are formed by synovial metaplasia and become intra-articular loose bodies. It is usually monarticular, most commonly affecting the knee and is regarded as invariably benign. There are reports of malignant change, but only the two case studies of Mullins, Berard and Eisenberg (1965) and of Dunn et al. (1974) fully document the development of chondrosarcoma in this condition. We report a patient with a long history of histologically proven synovial chondromatosis in whom the condition became clinically aggressive and underwent malignant transformation to chondrosarcoma.

Adult