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Biomedical subjects

C Andrews

Publications and source records attributed to C Andrews.

At least 91 records · Page 5Linked to original sources
PubMed1989

Lyme carditis: an important cause of reversible heart block.

Lyme disease is a tick-borne spirochetal infection, characterized by erythema chronicum migrans and an acute systemic illness. The disease is endemic in many parts of the north-eastern United States. Without treatment, late rheumatic, neurologic, and cardiac complications frequently occur. We report four serologically confirmed cases of Lyme carditis in previously healthy young men (mean age, 45 years) from endemic areas. Each presented with severe symptomatic atrioventricular block, three with episodes of prolonged ventricular asystole. Two had permanent pacemakers implanted (one was later removed), and another, very nearly did, before diagnosis. All four patients were treated with antibiotics, and in each case their rhythm returned to sinus, though one patient has Wenckebach second degree block with atrial pacing at 120 beats/min 16 months later. Carditis occurs in 4% to 10% of cases of Lyme disease and usually begins 3 to 6 weeks after the initial illness. It manifests as a transient myocarditis with varying degrees of atrioventricular block. The diagnosis is made primarily on clinical grounds and confirmed by serologic testing. Temporary cardiac pacing is frequently needed by patients who have severe heart block with hemodynamic instability. The evidence suggests that, in most cases, the block is at the level of the atrioventricular node. The block generally resolves completely with antibiotic treatment. Complete heart block rarely persists more than 1 week and the long-term prognosis appears to be excellent. Consideration and prompt recognition of this potentially lethal, but reversible, cause of heart block is crucial in order to avoid inappropriate permanent pacemaker implantation.

Adult↗
PubMed1989

Stage II endometrial carcinoma treated with external-beam radiotherapy, intracavitary application of cesium, and surgery.

From September 1972 to September 1987, thirty-six patients with stage II carcinoma of the endometrium were treated with external-beam radiotherapy to the pelvis, a single intracavitary application of cesium-137, and extrafascial hysterectomy with adnexectomy. Patients were followed for a median of 54.4 months. Overall 2- and 5-year actuarial survival rates were 83 and 58%, respectively. Survival was analyzed in terms of the independent variables surgical stage, presence of a gross cervical lesion, and residual disease within the myometrium or cervix. Factors contributing to patients survival were analyzed by the log-rank method. The 12 patients with a gross cervical lesion had an adverse prognosis, as compared to those without such a lesion (P less than 0.05). Seven of the twelve patients (58%) with a cervical lesion at clinical staging demonstrated persistent or recurrent disease. The presence of extrauterine disease at surgery was a major prognostic factor in patient survival (P less than 0.01). All six patients with extrauterine disease expired 2.3 to 53.0 months after hysterectomy. Two patients with persistence of disease expired 2.3 and 7.5 months after hysterectomy. Eleven patients developed recurrent disease 2.1 to 56.5 months after hysterectomy. All presented with distant metastases. Four of the thirteen patients with persistent or recurrent disease had no residual tumor within the myometrium.

Aged↗
PubMed1989

Assessment of pretreatment laparotomy in patients with cervical carcinoma prior to radiotherapy.

One hundred fifty-five patients with cervical cancer not amenable to radical surgery underwent selective, paraaortic lymphadenectomy and exploratory laparotomy prior to the initiation of radiotherapy. Fifty-one patients underwent transperitoneal lymphadenectomy; the remainder had the procedure performed using the extraperitoneal approach. Twenty-six patients (17%) were found to have metastatic disease to the paraaortic lymph nodes. The incidence of paraaortic metastases increased with advancing clinical stage. Twenty-four of the 26 patients were treated with extended-field radiotherapy which did not exceed 5100 cGy to the paraaortic region. Twenty-three percent of the patients with positive paraaortic nodes had documented intraperitoneal tumor. Two- and five-year actuarial survival rates for patients with paraaortic metastases were 35 and 27%, respectively. Approximately 4.6% of patients undergoing a selective paraaortic lymphadenectomy derived therapeutic benefit from the information supplied by the procedure. Using a Cox model, tumor histology, status of the paraaortic lymph nodes, tumor size, and presence of intraperitoneal disease were statistically significant prognostic factors in patient survival. Tumor size and presence of intraperitoneal disease were major predictors of patient survival.

Adenocarcinoma↗
PubMed1989

Treadmill assessment of an activity-modulated pacemaker: the importance of individual programming.

Maximum benefit from a rate-modulated pacemaker requires individualized programming of rate response settings. We tested an externally strapped activity-sensing pacemaker (Activitrax-Medtronic 8400) in eight healthy volunteers, to assess the pacing responses of the different rate response and activity threshold settings. Five males and three females, aged 20 to 70 years (mean 40), performed a total of 67 treadmill exercise tests, using a specific protocol designed to assess the activity-sensing unit. The external unit was compared to implanted units in four patients, to validate its accuracy. A reproducible sinus response to the treadmill protocol was observed, against which pacing responses were compared. The activity threshold determines the degree of activity required to elicit a pacing rate response, whereas the rate response setting determines the rate attained. Rates of 140 bpm were rarely achieved, despite vigorous exercise. The sensor responds rapidly to activity, not to physiologic demand; to increase in speed, not grade. Four patients performed repeated limited treadmill tests to determine their optimum program setting, with symptomatic status and the healthy volunteer sinus response as guides. These results, and those from the external Activitrax unit, suggest that LOW 6 and MEDIUM 6-10 settings will prove optimum for most patients.

Adult↗
PubMed1989

Clinical determinants of abnormalities in pulmonary functions in survivors of the adult respiratory distress syndrome.

Pulmonary function tests (PFTs) were performed in 39 survivors of the adult respiratory distress syndrome (ARDS) in whom clinical data had been prospectively collected during the acute episode. PFTs stabilized within 6 months of the episode and had returned to normal in most survivors. Persistent abnormalities were found after 6 months in diffusing capacity (14 of 23 patients, 61%), vital capacity (10 of 23 patients, 43%), and total lung capacity (five of 24 patients, 21%). To clarify the mechanisms underlying these persistent abnormalities, we attempted to correlate long-term PFT outcomes with estimates of the severity of initial lung injury as assessed from clinical data and with other features of the patient's course. The severity of lung function impairment during the first 3 days of ARDS was not related to long-term PFT values. However, a lower DLCO was related to a higher AaDO2, higher pulmonary artery pressure, and worse radiographic appearance on Days 4 through 7 and to the occurrence of sepsis. A lower FVC was related to higher pulmonary vascular resistance in Days 4 through 7 of ARDS. Long-term values for FVC and TLC were directly related to increasing levels of PEEP applied from Days 4 through 7 of ARDS in patients with peak airway pressures less than 50 cm H2O. Long-term abnormalities of pulmonary function of survivors of ARDS were not related to initial lung impairment but were directly related to persistence of impaired lung function during the acute episode. Recovery of lung function may also have been directly related to therapeutic modalities such as PEEP and impaired by the occurrence of sepsis.

Adolescent↗
PubMed1989

Efficacy of hyperimmune bovine colostrum for prophylaxis of cryptosporidiosis in neonatal calves.

Twelve neonatal calves were experimentally infected with oocysts of Cryptosporidium parvum. Six calves in group A fed hyperimmune colostrum at birth had significantly less diarrhea and shed oocysts for less time than did 6 calves in group B fed colostrum from cows that were not hyperimmune. Calves in group A had diarrhea for 0-4 days (means = 2.3 days), whereas calves in group B had diarrhea for 4-6 days (means = 5.0 days). Calves in group A shed oocysts for 4-9 days (means = 6.2 days), whereas calves in group B shed oocysts for 7-11 days (means = 8.5 days). These findings indicate that passive lacteal immunity conferred partial protection against cryptosporidiosis. Whether such protection was provided by the immunoglobulins that were highly elevated in the colostrum (greater than 1:200,000 for IgG1, IgM, and IgA) and constituted a large part of the circulating antibody in the calves, or by other biologically active factors, such as cytokines, is undetermined.

Animals↗
PubMed1988

Lysates of Sarcocystis cruzi bradyzoites stimulate RAW 264.7 macrophages to produce tumor necrosis factor (cachectin).

Lysate of Sarcocystis cruzi bradyzoites induced RAW 264.7 macrophages to release a factor that killed L 929 cells. Rabbit antibody to murine tumor necrosis factor (TNF) inhibited this killing effect, indicating that the factor causing cell death was similar to TNF (also called cachectin). Based on the present findings we hypothesize that TNF mediates, at least in part, the disease associated with this parasitic infection.

Animals↗
PubMed1987

Comparison of myopotential interference in unipolar-bipolar programmable DDD pacemakers.

Myopotential interference (MPI) can inhibit or trigger single and dual chamber unipolar pacemakers while bipolar pacemakers are resistant. Twenty units of two different models of dual chamber pacemaker, each capable of being programmed to single chamber or dual chamber and unipolar or bipolar function were tested to provoke myopotential interference. No patient had evidence of myopotential interference at any sensitivity setting in the bipolar configuration either in atrium or in ventricle. All patients (20/20) interfered with pacemaker function at the highest atrial or ventricular sensitivity settings in the unipolar configuration. T wave sensing occurred at the 0.25 mV sensitivity setting in four patients in pacemaker model 925, in both bipolar and unipolar configurations. Twenty-five percent of patients had myopotential interference at the unipolar atrial sensing threshold and did not allow a setting which would reject myopotential interference while providing satisfactory atrial sensing. Twenty percent (2/10) had myopotential caused ventricular inhibition at the least sensitive ventricular channel setting in model 240G so that myopotential interference could not be avoided in that unit no matter how large the electrogram.

Arrhythmias, Cardiac↗
PubMed1987

Retained pacemaker leads.

Increasingly, functionless pacemaker leads are being abandoned in place because they cannot be safely removed. One hundred eighty-nine intact or partially removed pacemaker leads were abandoned in situ in 152 patients between Jan. 1, 1965, and Dec. 31, 1985. The leads, sometimes several leads in a single patient, were deemed uninfected at the time of abandonment in 137 patients and contaminated with Staphylococcus epidermidis in 15 patients. All of the contaminated leads have remained clinically uninfected during follow-up. One clean lead became infected early after implantation and the patient died after an open cardiac operation to remove that lead and an adjacent abandoned lead that was adherent to the subclavian vein. No other patient has had a late complication during follow-up to 256 months (mean 47.6). Properly managed abandonment of an uninfected lead can carry a very low complication rate.

Electrodes, Implanted↗
PubMed1986

Suppression of concanavalin A-induced blastogenesis by HTLV-III-infected H9 cells.

The ability of cells infected with human T lymphotropic virus type III (HTLV-III) to suppress lymphocyte responses to concanavalin A (ConA) was evaluated. Thirty homosexual men, both HTLV-III seropositive and seronegative, and 11 seronegative laboratory personnel were studied. Peripheral blood lymphocytes from all groups had lower responses to ConA in the presence of HTLV-III-infected H9 cells than in the presence of uninfected H9 cells. Among HTLV-III-seropositive males, responses to ConA in the presence of infected or uninfected H9 cells correlated with the number of T4 cells present. The studies suggest that HTLV-III-infected cells can suppress normal lymphocyte responses. Possible mechanisms of this suppression are discussed.

Concanavalin A↗
PubMed1986

Detection of fungal antigen in body fluids for diagnosis of invasive aspergillosis.

In clinical trials, the diagnostic utility of a radioimmunoassay (RIA) to detect Aspergillus antigen was demonstrated in sera obtained from patients with invasive pulmonary, endothelial, and disseminated aspergillosis, in cerebrospinal fluids from patients with Aspergillus meningoencephalitis, and in bronchoalveolar lavage fluids from patients with invasive pulmonary aspergillosis. The RIA was further evaluated in three blinded, controlled clinical trials. In one, sera were collected prospectively from patients with acute leukemia. Antigenemia was detected in four patients with invasive pulmonary aspergillosis (IPA) due to A. flavus, appeared early in the course of infection of three patients concurrent with the onset and evolution of lung infiltrates, and remitted with antifungal chemotherapy. Antigenemia was not detected in three patients before the onset of IPA, in eight leukemic controls, or in the 24 normals. In contrast, seven bronchoscopies were performed in five patients with IPA; fungi were not isolated in three. In a second study, antigenemia was found in coded sera from two patients with invasive aspergillosis but not in eight controls. In the third controlled study, 616 sera from 79 hematology patients admitted on 152 occasions were analyzed for circulating fungal antigen. The diagnostic utility of the RIA was confirmed and levels of antigenemia correlated with the patients' clinical course. These studies demonstrate the utility of the Aspergillus antigen RIA for diagnosis of invasive aspergillosis in hospitalized high risk patients.

Animals↗
PubMed1986

Sibling preparation classes for preschool children.

The purpose of this study was to evaluate the effect of sibling preparation classes on the behavior of firstborn children following the birth of the family's second child. The maternal perceptions of the preschool child behaviors of two groups of mothers, one group of 17 mothers whose children attended sibling preparation classes and one group of 16 mothers whose children did not attend classes, were determined prior to and after the birth of the second child using the Maternal Perception of Preschool Child Behavior (Knicely, 1981). It was hypothesized that prenatal perceptions of child behavior would differ from postnatal perceptions for both groups. No significant difference between the two groups was found. Although the value of the classes may not have been clearly supported by the study, there are theoretical indications that the classes are valuable. Further study needs to be done on the effectiveness of sibling preparation classes. Several aspects of this research can be strengthened and the research repeated. Implications for further research are indicated.

Anxiety, Separation↗