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Biomedical subjects

B Brandt

Publications and source records attributed to B Brandt.

At least 163 records · Page 9Linked to original sources
PubMed1981

Intramyocardial electrical and metabolic activity during hypothermia and potassium cardioplegia.

Hypothermic potassium cardioplegia is widely used to reduce myocardial metabolism as a means of myocardial protection. To investigate the efficacy of intramyocardial electrical activity as an indicator of myocardial metabolism, 12 dogs were placed on cardiopulmonary bypass and myocardial oxygen consumption, partial pressure of carbon dioxide (PCO2) in the coronary sinus, myocardial temperature, and intramyocardial and surface electrocardiograms were measured. The hearts were fibrillated and cooled to 15 degrees C. In Group 1 (6 dogs), potassium cardioplegia was given at 15 degrees C. In Group 2 (6 dogs), it was given at 25 degrees C. Maximum coronary sinus PCO2 and oxygen consumption occurred at 36 degrees C and gradually decreased, but there was still evidence of metabolic activity and intramyocardial electrical activity at 15 degrees C. When cardioplegia was given at 15 degrees C, all electrical activity ceased and there was a further significant reduction in metabolic activity (coronary sinus PCO2 and oxygen consumption). In Group 2 similar findings were found at 25 degrees C, and there was no further reduction in metabolic activity at 15 degrees C. These data indicate that: (1) myocardial metabolic activity is lowest when there is electrical quiescence as measured with an intramyocardial electrode; (2) potassium arrest and hypothermia are both necessary to achieve electrical quiescence; and (3) in the potassium-arrested heart, lowering temperature from 25 degrees to 15 degrees C does not result in a further reduction of metabolic activity.

Animals↗
PubMed1980

Surgical management of pulmonary metastasis.

Because of the clarity of roentgenograms, the lungs act as a window to the body through which we can "watch" the growth of a metastatic tumor. By obtaining serial roentgenograms, we can follow the course of a tumor, as well as its response to different forms of therapy. Usually the mass seen on roentgenogram is only part of a larger tumor found in other metastatic deposits. However, Farrell, in a study of 75 cases, found that 15% of the patients had metastatic lesions confined to the lung. Therefore, a finding of pulmonary metastasis should not imply a completely hopeless prognosis. Many patients may benefit from pulmonary resection of a metastatic lesion, either in terms of ultimate cure or by palliation. This report will discuss the pathogenesis of pulmonary metastasis and the surgical approach based on histology and biologic behavior of these tumors and current concepts of oncology as viewed through the study of pulmonary metastasis.

Breast Neoplasms↗
PubMed1980

Surgical treatment of left main coronary artery disease: operative risk.

Surgical experience with 100 consecutive patients with left main coronary artery stenosis (greater than 50%) was reviewed to determine the risk factors and their relationship to preoperative use of intraaortic balloon (IAB). The 30-day mortality rate was 3% and the perioperative infarction rate was 2%. There was no correlation between surgical mortality and ejection fraction (EF) (15% had EF of less than 40%), degree of stenosis (58% of the patients had greater than 70% left main stenosis), right coronary artery stenosis (81%), or the number of grafts placed. We conclude that surgery for left main coronary artery disease can be done with a low mortality rate by strict attention to the induction of anesthesia, surgical technique, and complete revascularization. In our experience, prophylactic use of the IAB does not appear to be justified and is only rarely necessary for postoperative support (one case).

Adult↗
PubMed1979

Surgical treatment of atrial myxomas: early and late results of 11 operations and review of the literature.

Eleven patients underwent surgical excision of atrial myxomas during a 15-year period, with no hospital deaths. The operation consisted of excision of the tumor with a generous portion of atrial septum or wall. Patch reconstruction of the atrial septum was required in most patients. There were 2 late deaths (14 and 121 months after operation). Late recurrences have been reported in other series but no recurrences were diagnosed in any of the patients in this series reexamined by echocardiography 7 to 156 months (mean, 48 months) after operation. Late functional results were excellent (78%, New York Heart Association Class D. The pertinent literature is reviewed.

Adolescent↗
PubMed1979

Ventricular septal defect following myocardial infarction.

Review of the literature since 1970 revealed more than 200 patients who had a ventricular septal defect following myocardial infarction and underwnet operation. Pathogenesis and diagnosis are discussed. The primary therapy is operative repair, which is considered from the standpoint of approach, timing, technique, concomitant coronary artery bypass, mortality, and long-term survival. Operative mortality in those patients operated on less than 3 weeks following perforation remains high (40%) but when it is possible to wait 3 weeks, there is a marked decrease in mortality (6%). Several general principles have evolved for the care of these patients. (1) Operation should be deferred until 3 weeks after infarction if possible. (2) The intraaortic balloon allows preoperative evaluation of the patient with clinical hemodynamic deterioration in the early postinfarction period. (3) The incision should be placed through the infarct. (4) Associated coronary artery or mitral valve disease should be repaired as well.

Cardiac Catheterization↗
PubMed1979

A randomized study of instructional variations in nutrition counseling and their efficacy in the treatment of hyperlipidemia.

The important of the educational diagnosis in instructing patients in a fat modified diet was examined in a double blind study. The educational diagnosis depended upon the assessment of three independent instructional parameters: the amount of structure, the teaching mode, and the language code preferred by the patient. Group I (67 patients) received traditional personalized counseling for 3 months. Group IIa (40 patients), whose instruction was matched to their preferred education attributes, was randomized against group IIb (36 patients), whose instruction was mismatched. Group IIIa (33 patients), receving matched instruction was randomized against group IIIb (35 patients), receiving high structure in the symbolic mode of instruction. The greatest reduction in serum cholesterol was seen in group I. At 3 months, no significant difference in serum cholesterol reduction could be shown between groups IIa and IIb, or IIIa and IIIb. However, the mean cholesterol reduction became significantly greater (P less than 0.05) in IIa than IIb at the 6 month visit. Seven day food diaries showed no significant differences in dietary intake and 1 and 3 months between matched and unmatched groups. The data did suggest that patients preferring high structure in the symbolic mode had a greater serum cholesterol reduction that other diagnostic groups. Analysis of variance showed an interaction between the preferred and instructional level of structure as related to the change in total fat, and saturated fat of the diet after 3 months.

Audiovisual Aids↗
PubMed1976

Changes in anticoagulation in dogs assayed by three methods.

As a preliminary to a membrane oxygenator study, a study was made of clotting indices in dogs and their intercorrelation and relationship to human data. The most useful criterion for monitoring coagulation in experimental extracorporeal systems was sought. Linear regression and correlation analysis indicated that activated partial thromboplastin time (APTT) predicted whole blood clotting time with a correlation of 0.77 (p less than 0.01). Changes in the APTT with time after heparinization were similar to those previously reported in man, making the animal model an acceptable one for use in developing extracorporeal systems such as the membrane oxygenator. When blood activated recalcification time (BART), APTT, and whole blood clotting time (WBCT) assays were compared on the basis of applicability to studies of extracorporeal support, the APTT and the BART assays proved superior to the WBCT assay due to their reduced variability and increased speed of determination. The variability of the BART assay was the lowest, and its sensitivity was the same as the APTT assay. The principal drawback to the BART assay was not experienced in this study; that is, its dependence on adequate platelet levels which are unpredictable in extracorporeal systems.

Animals↗
PubMed1975

Pulmonary artery pressure and lung water during extracorporeal circulation in experimental pulmonary insufficiency.

Use of the membrane oxggenator has been advocated in the management of severe respiratory insufficiency. We have compared this method to conventional therapy in an experimental model in which 23 dogs were subjected to aspiration with 0.1 N HC1 and 18 were supported with a volume respirator and positive end-expiratory pressure or placed on partial bypass using a membrane oxygenator for 12 to 24 hours. Adequate oxygenation (POX greater than 100 mm Hg) was achieved with the membrane oxygenator. The increase in lung weight during conventional therapy was significantly greater than during membrane oxygenator support. Extracorporeal support during recovery from severe pulmonary injury allows pulmonary artery pressure to be controlled and reduces the expected increase in lung water.

Animals↗
PubMedDate not supplied

Repair of coarctation of the aorta in children with Turner syndrome.

Increased risk of perioperative hemorrhage has been described in patients with Turner syndrome and coarctation of the aorta. We have operated on 11 patients with Turner syndrome and coarctation of the aorta, two of whom developed bleeding. One patient died. End-to-end anastomosis was performed in all patients. Histologic studies of resected specimens did not reveal any abnormalities. The risk of bleeding was not related to age at the time of repair or postoperative hypertension. Although no specific abnormality has been identified in these patients, the risk of serious hemorrhage appears increased.

Aortic Coarctation↗
PubMedDate not supplied

Procainamide for rate control of postsurgical junctional tachycardia.

This study was conducted to determine the efficacy of procainamide therapy for rapid rate control of postoperative junctional tachycardia (JT). Postoperative JT is one of the most difficult forms of tachycardia to manage. Reported success with a variety of treatments of JT in infants and children has been inconsistent and limited. Rate control using procainamide was achieved in 17 children having rapid JT (heart rate >200 beats/min) between 1986 and 1997. In the first 5 patients (protocol A), following a loading dose of 3 mg/kg over 20 minutes, a continuous procainamide infusion was initiated at a rate of 20 microg/kg/min. The infusion dose was increased in 10 microg/kg steps every 30 minutes to 40-120 microg/kg/min until the heart rate decreased below the target rate of 180 beats/min. In the other 12 patients (protocol B), after a higher loading dose of 10 mg/kg the infusion rate was increased every 10-15 minutes until the heart rate decreased below the target rate of 180 beats/min. Procainamide decreased JT rates in all patients but the response was significantly faster in protocol B. In the patients treated with protocol A, pretreatment JT rates ranged from 203 to 240 (213+/-17) beats/min and decreased to 195+/-10 beats/min at 2 hours (p = ns), 186+/-8.8 at 4 hours (p<0.02), and 179+/-8 at 6 hour postinitiation of PA. In protocol B, pretreatment JT rates ranged from 201 to 240 (218+/-17) beats/min and decreased to 183+/-20 beats/min at 2 hours (p<0.001) and 171+/-12 at 4 hours after starting the procainamide therapy. The mean duration to decrease JT rates below the target rate of 180 beats/min was 3.2+/-1.1 hours in protocol B compared to 6.4+/-3.8 hours in protocol A (p<0.02). Eight of 12 patients in protocol B achieved rate control below the target rate of 180 beats/min within 4 hours despite remaining on significant inotropic support. The procainamide infusion rates to maintain heart rates below 180 beats/min were 40-120 (68.4+/-22.1) microg/kg/min. No proarrhythmia, bradycardia, or significant hypotension was observed. In this series procainamide provided safe, effective, and rapid rate control of JT occurring in the immediate postoperative period.

Analysis of Variance↗
PubMedDate not supplied

Modulation of EGFR gene transcription by a polymorphic repetitive sequence--a link between genetics and epigenetics.

The epidermal growth factor receptor (EGFR) plays a crucial role in growth, differentiation and motility of normal as well as tumor cells. The transduction of extracellular signals to the cytoplasm via the receptor not only depends on ligand binding, but is also determined by the receptor density on the cell surface. Therefore, with regard to cancer diagnosis and therapeutic approaches targeting EGFR it is important to know how the expression level of EGFR is controlled. We found that transcription activity declines with increasing numbers of CA dinucleotides of a highly polymorphic CA repeat in the first intron of the epidermal growth factor receptor gene. In vivo data from cultured cell lines support these findings, although other regulation mechanisms can compensate this effect. In addition, we showed that RNA elongation terminates at a site closely downstream of the simple sequence repeat (SSR) and that there are two separate major transcription start sites. Model calculations for the helical DNA conformation revealed a high bendability in the EGFR polymorphic region, especially if the CA stretch is extended. These data suggest that the CA-SSR can act like a joint, bringing the promoter in proximity to a putative repressor protein bound downstream of the CA-SSR. The data indicate that this polymorphism may be a marker for cancer, linking genetic and epigenetic risk factors. Furthermore, in breast cancer, heterozygous tumors with short CA-SSR showed an elevated EGFR-expression in contrast to tumours with longer CA-SSR. Tumours with loss of heterozygosity in intron 1 of egfr revealed an increased EGFR expression if the longer allele was lost. Moreover, decreased EGFR gene levels were significantly correlated with poor prognosis in breast cancer.

Biomarkers, Tumor↗
PubMedDate not supplied

Blood-borne cancer cells--quo vadis?

The detection of blood-borne cancer cells may help in clinical staging and further understanding of cancer metastasis. We developed a cytokeratin-based immunomagnetic method to isolate epithelium-derived cells from the circulating blood of patients. The number of cell clusters positive for cytokeratin/prostate-specific antigen (PSA) from the peripheral blood of prostate cancer patients and cytokeratin/p185c-erbB-2 from the peripheral blood of breast cancer patients has been related to stage of the disease. Breast cancer patients who presented cytokeratin/p185c-erbB-2-positive cell clusters showed a decrease in such cells under adriamycin adjuvant therapy with Further molecular characterization by a highly sensitive microsatellite multiplex-PCR enabled reproducible detection of microsatellite alterations. The impact of these individually targeted results may contribute to an individual diagnostic and therapeutic strategy.

Biomarkers↗