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Biomedical subjects

J Anderson

Publications and source records attributed to J Anderson.

At least 577 records · Page 32Linked to original sources
PubMed1989

Initial experience with a microprocessor controlled current based defibrillator.

Intramyocardial current flow is a critical factor in successful ventricular defibrillation. The main determinants of intramyocardial current flow during transthoracic countershock are the selected energy and the transthoracic impedance of the patient. To optimise the success of the first shock and to titrate energy dosage according to each patient's transthoracic impedance, a microprocessor controlled current based defibrillator was developed. It was compared with a conventional energy based protocol of 200 J (delivered energy), 200 J, then 360 J if required in 42 consecutive episodes of ventricular fibrillation in 33 men and seven women. The mean (SD) predicted transthoracic impedance was 69.9 (14.0) omega. First shock success with the standard protocol was 80.9%, and first or second shock success was 95.2%. The microprocessor controlled current based defibrillator automatically measured transthoracic impedance and calculated the energy required to develop a selected current in each patient. A current protocol of 30 A, 30 A, then 40 A, if required, was used in 29 men and 12 women with 41 episodes of ventricular fibrillation. Transthoracic impedance (mean 65.1 (15.9) omega) was similar to that in the energy protocol group and success rates for first shock (82.9%) and first or second shocks (97.5%) were also similar. The mean delivered energy per shock with the current based defibrillator for first or second shock success was significantly less (144.8 J) with the energy protocol (200 J). The mean peak current of successful shocks was also significantly reduced (29.0 v 31.9 A). A current based defibrillator titrates energy according to transthoracic impedance; it has a success rate comparable to conventional defibrillators but it delivers significantly less energy and current per shock.

Cardiography, Impedance↗
PubMed1989

Primary and secondary syphilis, 20 years' experience. 3: Diagnosis, treatment, and follow up.

The methods of diagnosis (dark ground microscopy and serology), treatment, and follow up of 946 patients with primary and 854 with secondary syphilis who presented to a London STD clinic between 1965 and 1984 were reviewed retrospectively. On dark ground microscopy spirochaetes typical of Treponema pallidum were seen in 673 (78%) of 884 patients with primary syphilitic chancres. Of the patients with primary syphilis, 137 (14.5%) had negative serology results at presentation. Eight (0.9%) of the patients with secondary syphilis had negative results at presentation, but seven of these gave positive results one month later. Procaine penicillin was the treatment used most, and erythromycin the commonest alternative. The Jarisch-Herxheimer reaction occurred more often after treatment with penicillin than with erythromycin or tetracycline (p less than 0.005). In most patients the Venereal Diseases Research Laboratory (VDRL) test showed a consistent fall in titre after treatment; a small proportion, however, continued to give positive results (some at a high titre) with no other evidence of reinfection or treatment failure.

Erythromycin↗
PubMed1989

Effect of hematocrit on microvascular pressures in 3- to 5-wk-old rabbit lungs.

To examine the effects of blood hematocrit (Hct) and apparent viscosity on the pulmonary microcirculation, we studied 30 isolated, perfused 3- to 5-wk-old rabbits with varying perfusate Hct. We partitioned total vascular resistance by measuring pulmonary artery and left atrial pressures and by micropuncture the pressures in the subpleural microcirculation in 20-40 microns diameter arterioles, 20-40 microns venules, and 250-300 microns venules. To prevent active vasomotion and changes in vessel geometry, we paralyzed the vasculature with papaverine hydrochloride. We studied four groups of lungs: group I (n = 7) with low Hct (17.8 +/- 2.4%); group II (n = 9) with medium Hct (46.8 +/- 8.2%); group III (n = 6) with high Hct (74.4 +/- 5.8%); and group IV (n = 8) with both low and high Hct perfusates. Lungs were perfused at constant flow (80 +/- 4 ml.kg body wt-1.min-1) in zone 3, airway and venous pressures being 6 and 8 cmH2O, respectively. We found that in lungs perfused with low Hct, approximately 52% of the total resistance was in arteries, approximately 25% in microvessels, and approximately 21% in small veins, with very little resistance in large veins. With an increase in perfusate hematocrit and apparent viscosity, total pulmonary vascular resistance increased mainly because of an increase in resistance in arteries and small veins, with little change in resistance in microvessels and large veins.

Animals↗
PubMed1989

Prognostic significance of cytokeratin-positive breast cancer metastases.

The most important discriminant in staging carcinoma of the breast is the presence of positive axillary lymph nodes. In this study, we determined if 45 female breast cancer patients originally classified as lymph node-negative by standard light microscopy (SLM) could be more accurately classified by immunohistochemical (IH) examination of their lymph nodes with an anticytokeratin monoclonal antibody cocktail. Identical sections of lymph nodes were sequentially examined by SLM and IH. Eight nodes (1%) in a total of five patients (11%) were positive by SLM. In comparison, 12 nodes (1.5%) in a total of nine patients (20%) were positive by IH. Five nodes were positive by IH and negative by SLM. There was no correlation between IH-detected metastases and tumor size or patient age. The survival curve for patients with IH-detected metastases was significantly worse than that of patients without IH-detected metastases. IH detection methods may be an important adjunct in staging breast cancer patients.

Adenocarcinoma↗
PubMed1989

Severe protein energy malnutrition in Lesotho, conditioning factors and death and survival in hospital.

Information was obtained on infants and children admitted for severe protein energy malnutrition (PEM) to Lesotho's central hospital in 1981 and 1982 as regards feeding pattern, socio-economic, environmental factors and vaccination status. Acute gastroenteritis (GE) appeared to be a major precipitating cause in the development of severe PEM. Of children 13-24 months of age only 13% was still breast fed. Compared to kwashiorkor significantly more children with marasmus or marasmic kwashiorkor had never been breast fed, or were early weaned and bottle fed. Above age nine months, children had a similar diet during the last three days before admission. Children of nevermarried single mothers appear to be more at risk for severe PEM. Absence of the father's support and a grandmother as caretaker may be other risk factors as well. The vaccination status was poor. In marasmus death was significantly (p less than 0.01) associated with bottle feeding and survival (p less than 0.05) with breast feeding. In kwashiorkor death was significantly (p less than 0.01) associated with an unprotected source of drinking water and survival (p less than 0.05) with consumption of green vegetables in the last three days before admission and employment of the mother. Data collection in hospital may provide a rationale for interventions in the development of severe PEM and identify those at risk to die from it.

Breast Feeding↗
PubMed1989

Peripheral neuropathy as an early marker of AL amyloidosis.

Fifty-one of 146 patients with primary amyloid deposits of light-chain origin (AL) examined between 1972 and 1986 were found to have peripheral neuropathy as part of their systemic amyloidosis. Peripheral neuropathy was the presenting symptom in 11 patients, and it was a later symptom or an incidental physical examination finding at the time of amyloid workup in 40 additional patients. The median duration of time from first symptom to the diagnosis of primary amyloidosis was longer in those whose first symptom was neuropathy (48 months vs 12 months). In addition, survival time after diagnosis for these patients was significantly longer (at least 35 months vs 16 months). Peripheral neuropathy is not an uncommon symptom of primary amyloidosis and may mark the onset of the disease process years before infiltration of vital structures of the heart, kidneys or gastrointestinal tract leads to failure and a subsequent downhill course. Appreciating amyloid disease at this early stage may widen the potential therapeutic window.

Amyloidosis↗
PubMed1989

Hemin-induced erythroid differentiation changes the sensitivity of K562 cells to tumor necrosis factor-alpha.

Tumor necrosis factor-alpha (TNF) can inhibit the growth of erythroid progenitors (erythroid colony-forming units [CFU-E] and erythroid burst-forming units [BFU-E]) at picomolar concentrations, but only if added within the first 48 h of culture. These data suggested that cells undergoing erythroid differentiation become resistant to TNF. To test this hypothesis, K562 cells were treated with hemin to induce erythroid differentiation and then tested for their sensitivity to TNF in terms of growth and TNF receptor expression. TNF inhibited the growth of untreated K562 cells, but not hemin-treated K562 cells. Untreated K562 cells expressed TNF receptors, whereas few hemin-treated K562 cells expressed TNF receptors within 24 h of exposure to hemin. These data show that K562 cells induced to differentiate along the erythroid pathway are resistant to TNF because they lack TNF receptors and suggest that the resistance of erythropoietin-treated human bone marrow cells to TNF added after 48 h of culture may also reflect loss of TNF receptors associated with erythroid differentiation.

Cell Differentiation↗
PubMed1989

Cesarean delivery and hysterotomy using an absorbable stapling device.

The absorbable stapling device was used in 22 hysterotomies in gravid rhesus monkeys. The efficacy of the device, subsequent fertility and delivery route, fetal effects, and pathohistology were all studied. No statistically significant difference between experimental and control animals was noted.

Animals↗
PubMed1988

Automatic implantable cardioverter defibrillators and survival of patients with left ventricular dysfunction and malignant ventricular arrhythmias.

STUDY OBJECTIVE: To assess survival after insertion of automatic implantable cardioverter defibrillators in high-risk patients who have malignant ventricular arrhythmias and left ventricular dysfunction. DESIGN: Actual survival time compared with arrhythmia-free time in a single group of patients. SETTING: Inpatient services of a tertiary referral center and outpatient follow-up. PATIENTS: Seventy consecutive patients with clinical sustained ventricular tachycardia or fibrillation whose arrhythmia could not be controlled by medication as determined by programmed electrical stimulation, and who had an automatic cardioverter defibrillator implanted. INTERVENTION: All patients received an implantable defibrillator. MEASUREMENTS AND MAIN RESULTS: Two-year survival was 93.4% (95% CI, 87 to 99.8) and projected survival based on recurrence of malignant arrhythmias was 60.3% (CI, 47.3 to 73.3; P less than 0.001). In the 25 patients with left ventricular ejection fraction less than 30%, actual survival was 86.7% (CI, 72.3 to 91.1) and projected survival was 56.9% (CI, 35.9 to 77.9; P = 0.025). Projected survival percentages are similar to survival figures reported in the literature for such high-risk patients. There was only one sudden death; the remaining deaths were not arrhythmic in nature. Of the 65 patients who were alive at the end of follow-up, 13 were in New York Heart Association Class I; 44, Class II; 5, Class III; and 3, Class IV. CONCLUSIONS: The automatic implantable cardioverter defibrillator is probably highly effective in preventing arrhythmic mortality even in high-risk patients. Such treatment does not appear to significantly impair a patient's functional status.

Actuarial Analysis↗
PubMed1988

Assessment of a device for trans-telephonic control of defibrillation.

The safety and efficacy of a device allowing the trans-telephonic control of defibrillation have been assessed in 32 attempted defibrillations performed in 29 patients. The initial rhythm was atrial fibrillation in 27; ventricular tachycardia in 4; and ventricular flutter in 1. Satisfactory voice and ECG transmission were established in all cases. The mean time taken by the patient unit to dial and activate the base station was 20.3 seconds. The mean defibrillator charge time was 5.5 seconds to 50 joules and 9.3 seconds to 360 joules. A total of 84 synchronised and 5 unsynchronised shocks were delivered satisfactorily. Lay persons were trained to use the patient unit, and were able to operate the device at home. This device has the potential for rapid defibrillation of patients who develop ventricular fibrillation outside hospital.

Adult↗
PubMed1988

Phase II trial of ifosfamide and mesna in previously treated patients with non-Hodgkin's lymphoma: Cancer and Leukemia Group B Study 8552.

Ifosfamide (1.25 g/m2 intravenously/day x 5) with mesna (20% of the ifosfamide dose x six doses on each day of ifosfamide therapy) was administered to 46 previously treated patients with non-Hodgkin's lymphoma of which 31 were eligible and evaluable. A 29% response rate (9/31) was observed (2 CR and 7 PR) with a median duration of response of 2.5 months. Myelosuppression was dose-limiting. Hemorrhagic cystitis was observed in three patients (10%). Nausea and vomiting was generally mild or moderate. One patient developed transient neurotoxic symptoms with confusion and disorientation. An additional patient developed an anaphylactic-type reaction with shortness of breath and respiratory strider during the fourth course of therapy. Ifosfamide, as a single agent, produces remissions of limited duration in non-Hodgkin's lymphoma in patients in second or third relapse.

Adolescent↗
PubMed1988

Treatment of refractory lymphoma with methotrexate, VM-26 (teniposide), procarbazine, and dexamethasone: Cancer and Leukemia Group B study 7902.

Seventy-eight individuals previously treated with chemotherapy for non-Hodgkin's lymphoma were enrolled in a phase II pilot study employing methotrexate 100 mg/M2 iv (day 1), calcium leucovorin 10 mg/M2 iv and/or po q6h (days 2-4), VM-26 (teniposide) 100 mg/M2 iv (days 2 and 9), procarbazine 100 mg/M2 po (days 2-15), and dexamethasone 15 mg/M2po (days 2-8) (MV26PD). Thirty percent of the 78 patients treated had a response to therapy (8% complete, 22% partial). Twenty-four percent of patients with diffuse histiocytic (large cell) lymphoma had a response (12% complete, 12% partial). The estimated failure-free survival was 41% at 3 months and the median survival (death from any cause) was 4.5 months for the entire cohort. Two individuals, including one individual with diffuse histiocytic lymphoma, remain in a complete response for over 900 days. Significant hematologic toxicity and infectious complications were seen in this heavily pretreated group of patients. MV26PD represents an active combination of agents for the treatment of non-Hodgkin's lymphoma. The optimal dosing for MV26PD remains to be determined.

Adult↗
PubMed1988

Risk identification at the time of admission to coronary care unit in patients with suspected myocardial infarction.

The in-hospital clinical course was evaluated in 2,162 consecutive patients admitted with a diagnosis of suspected myocardial infarction. Of these, 1609 patients were considered to be in the high-risk group, based on the presence of 16 clinical criteria present at the time of admission. The remaining 553 patients were classified as low risk. The overall rate of complications in the coronary care unit was greater in the high-risk group, 64%, compared to 26% in the low-risk group (p less than 0.001). Similarly life-threatening events (occurrence or recurrence of ventricular fibrillation, sustained ventricular tachycardia, complete heart block, asystole, or cardiogenic shock) were more common in the high risk-group compared to the low-risk group, 11% and 0.9%, respectively (p less than 0.001). The high-risk group required significantly more interventions, such as electrical cardioversion, temporary pacing, pulmonary artery catheterization, and intraaortic balloon counterpulsation, compared to the low-risk group (20% vs 2%, respectively; p less than 0.001). Myocardial infarction was confirmed in 892 patients in the high-risk group (55%) compared to 90 (16%) in the low-risk group (p less than 0.001). The coronary care unit mortality rate was greater in the high-risk group compared to the low-risk group (8.2% vs 0.4%, respectively; p less than 0.0002). It is concluded that based on readily available clinical criteria at the time of admission, a subgroup of patients at low risk for developing life-threatening complications requiring coronary care unit interventions can be identified and admitted directly to an intermediate-care unit.

Coronary Care Units↗