Dynamic in vitro and in vivo performance of a permanent total artificial heart.

In vivo characterization studies were performed to compare the dynamic in vivo performance of the Penn State/3M Health Care electric total artificial heart to existing in vitro data. Fully implanted systems were utilized including the artificial heart, controller, backup batteries, compliance chamber, and transcutaneous energy transmission. Catheters were implanted to measure central venous pressure (CVP), left atrial pressure (LAP), right atrial pressure (RAP), pulmonary artery pressure (PAP), and aortic pressure (AoP). Cardiac output (CO) was determined from the implanted controller, and systemic vascular resistance (SVR) was calculated. Steady state data were collected for each animal along with data regarding the transient responses to changes in preload and afterload. Preload was manipulated through volume changes. Afterload changes were accomplished through vasoactive agents. Increased preload caused little change in cardiac output because the pump output was nearly maximum at baseline. LAP, AoP, and SVR increased with increasing RAP. Decreased preload caused a reduction in CO, LAP, and SVR. Afterload increase resulted in a slight decrease in flow and an increase in system power and SVR. Afterload reduction was accompanied by a decrease in preload and a concomitant reduction in flow. Overall, the system response was similar to the response observed in vitro.

Expression and degeneration of tenascin-C in human lung cancers.

Tenascin-C is an extracellular matrix glycoprotein produced in response to epithelial-mesenchymal interactions during organogenesis and tissue remodelling. It has therefore been proposed as a stromal marker for epithelial malignancy. To test this hypothesis, 30 human lung cancers, presenting a variety of clinicopathological features, and six specimens of normal tissue were examined by Western and Northern blotting of tenascin-C protein and mRNA. The results obtained were: (1) elevated tenascin-C expression was detected in all 30 cases by Western blotting, with mRNA increase in 22 of them; (2) mRNA for a large isoform of tenascin-C, including an alternatively spliced sequence, was expressed in lung cancer tissues but not in normal lungs; and (3) metastasis to lymph nodes was frequently found in cases whose tenascin-C was degraded into small fragments. These results suggest that tenascin-C degradation can be used as a marker for metastatic potential of a tumour.

Recent improvements in a completely implanted total artificial heart.

The total artificial heart under development by the Pennsylvania State University and 3M Health Care has undergone a number of design improvements to improve reliability, manufacturability, implantability, and performance. These improvements are nearing completion in preparation for formal durability testing. The redesigned implanted electronics canister, consisting of a welded titanium shell with hermetic connectors, contains the control, telemetry, and energy transmission electronics, as well as a 9 cell, 800 mAhr Ni-Cd battery pack. Functional changes include a reduction in the battery recharge time from 14 hours to 4 hours, and a new inductive telemetry system. The energy transmission system operating frequency has been increased from 160 kHz to 200 kHz. Electromagnetic interference filters and a more efficient control mode have also been implemented. The energy converter has been modified to incorporate a new motor with integral Hall effect position sensors, and new cable, and compliance chamber conduit fittings. High flex life cable is now used for the motor and coil cables. Two prototype durability mock circulatory loops have been built and are being tested. Substantial progress has been made in the completion of manufacturing documentation, and in the implementation of a quality system.

Is it true that cardiac operations with cardiopulmonary bypass impair the reticuloendothelial system?

Reticuloendothelial system (RES) function after cardiac operations is a controversial issue. Sequential changes in plasma fibronectin levels and RES phagocytic function were studied after a cardiac operation and a lung operation (control). In the cardiac operation group, the plasma fibronectin level decreased until the third postoperative day and increased thereafter. Reticuloendothelial system phagocytic function remained unchanged on the third postoperative day and then it increased. However, in the control group it increased significantly after operation. In the past, investigators have demonstrated a decline in plasma fibronectin levels following cardiac operation and have assumed that RES function was impaired. However, this sequential study showed that phagocytic function was not impaired, but its enhanced phase was delayed. Moreover, our previous morphologic studies demonstrated that RES function was potentially activated after cardiopulmonary bypass. It appears that the delay of the enhanced phase is caused by the overloading of substances which must be processed by the RES during cardiopulmonary bypass. Thus, we conclude that cardiac operation produces hyperactive, yet oversaturated RES function. There is no impairment of RES function after cardiac operations.

New surgical method of chordal replacement for mitral valve incompetence with echocardiographic guidance. An experimental study.

Chordal replacement with expanded polytetrafluorethylene suture has become a procedure of choice for repairing anterior leaflet prolapse among certain surgeons. However, most surgeons believe that the chordal replacement is too complicated and not reproducible. This report introduces a new method of chordal replacement using intraoperative epicardial and transesophageal echocardiography. Three dogs underwent the following procedures. One major marginal chorda of an anterior mitral leaflet was resected during cardiopulmonary bypass. A specially designed 3-0 polytetrafluoroethylene suture, having straight needles, was attached to the anterior leaflet by a mattress suture. Then the needles were brought from the root of the anterior papillary muscle to the outside of the left ventricle. After the bypass flow was reduced, both ends of the polytetrafluoroethylene suture were pulled under echocardiographic guidance until valve competence was achieved. At that point, the suture was temporarily tied. When cardiopulmonary bypass was discontinued, competence was again confirmed and the suture was tied permanently. When the procedures were completed, echocardiography showed trivial regurgitation and good pliability of the anterior leaflets in all animals. Left atrial pressures were sufficiently decreased. It appears that this new technique is reproducible for all surgeons because the optimal length of polytetrafluoroethylene chordae is determined with the valve functioning.

Clinical experience with Nikkiso centrifugal pumps for extracorporeal circulation.

A comparative study of a newly developed impeller-type centrifugal pump, Nikkiso HMS-15, was made to assess the effects on hemolysis, platelet function, and renal function for extracorporeal circulation (ECC) during open heart surgery. The Bio-pump (cone-type, Medtronic) and the roller pump were used as controls. The increase of serum hemoglobin level in the Nikkiso pump was significantly lower than that in the other pumps. The decrease of platelet counts was recognized after the initiation of ECC in the three pumps whereas the levels of platelet factor 4 and beta-thromboglobulin in the Nikkiso pump group increased by far less than in the other two groups. Moreover, renal function was better maintained in the Nikkiso pump group; in particular, a significantly higher urine output was recorded during ECC and for 1 h after the termination of ECC. The results of our clinical studies suggest that the Nikkiso centrifugal pump is suitable for ECC during open heart surgery.

Clinical experience using the Bio-pump for extracorporeal circulation during open-heart surgery.

The Bio-pump is still being used in a wide range of clinical applications such as open-heart surgery, left-heart bypass, extracorporeal membrane oxygenation, and supplementary circulation. Clinical application of the Bio-pump for extracorporeal circulation in 21 patients undergoing open-heart surgery was compared with application of the roller pump in terms of their effects on hemolysis, platelet function, and renal function. Although the amount of hemolysis was not significantly different between the Bio-pump group and the roller-pump group, platelet function was slightly better maintained in the Bio-pump group as judged by the levels of platelet factor 4, beta-thromboglobulin, and 6-keto-prostaglandin F1 alpha/thromboxane B2. There was no difference between the two pumps in terms of their effects on renal function. The above findings lead us to conclude that there is a slight advantage to use of the Bio-pump in clinical settings.

[Left atrial myxomas: clinical characteristics, evaluation and considerations in classifying tumors].

Eleven patients underwent surgical excision for left atrial myxomas. Clinical symptoms, coronary angiographic findings and operative procedures were evaluated. Myxomas were classified into two types based on macroscopical findings, and clinical characteristics of these two types were analyzed. Seven cases (64%) classified as "lobular-type myxomas" were seen as lobulated, gelatinous and fragile. Four cases (36%) were classified as "round-type myxomas" were round and elastic soft. Primary symptoms included dyspnea on exertion in five cases (45%) and neurological disturbances in six cases (55%). Brain emboli were found in four patients by CT scan, and were classified as lobular-type myxomas. These eleven myxomas successfully removed in all cases. Four of these myxomas, which were pedunculated with fine fibrous stalks, were shaved along the base at the atrial septum or free wall. Others were excised completely along with a portion of the adjacent septum. Microscopic examination of the operative specimens revealed that two lobular-type myxomas with broad-based attachment to left atrial septum had invaded the atrial septum. All patients are doing well and have had no signs of myxoma recurrence at postoperative periods ranging from 10 months to 12 years (mean follow-up 5.3 years). Seven patients underwent selective coronary angiography due to a diagnosis of a coronary artery disease. All coronary angiograms were normal in all cases. In five (71%) of these seven, abnormally dilated atrial branches were seen as supplying the tumor. In two cases with round-type myxomas, neovascularity was evident and was made up of clusters of tortuous vessels with tumor blush.(ABSTRACT TRUNCATED AT 250 WORDS)

[DNA analysis of resected pulmonary adenocarcinoma].

The nuclear DNA content was determined by flow cytometry (FCM) in 155 resected specimens (122 paraffin-embedded and 33 fresh frozen specimens) of primary adenocarcinoma of the lung obtained at our department during the 8 years from 1982 to July, 1990. Aneuploid patterns were observed in 106 specimens (68.4%), and the diploid patterns in 49 (31.6%). No difference was observed in the age, sex, or clinical stage between the two groups. As for the relationship of the presence or absence of vascular infiltration with the DNA index (DI) and the heterogeneity index score (HIS), the percent positivity of vascular infiltration was 38.1% in the group with 1 less than or equal to DI less than 1.5 but nearly twice higher at 63.6% in the group with 1.5 less than or equal to DI. The percent positivity of vascular infiltration was 29.4% in the group with HIS less than 100 but 62.5% in the group with 100 less than or equal to HIS. Concerning the relationship between the ploidy pattern and outcome, the 5-year survival rate was 28.0% in the aneuploidy group and 65.1% in the diploid group, the outcome being significantly poorer in the first group. Concerning the relationship between DI and outcome, the 5-year survival rate was 14.9% in the group with 1.5 less than or equal to DI as compared with 55.4% in the group with 1.0 less than or equal to DI less than 1.5. DNA analysis was made also in bronchoscopic brushing specimens to examine the possibility of preoperative evaluation of the prognosis of lung cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

[Mitral prosthetic valve endocarditis diagnosed by transesophageal echocardiography--a surgical case report].

The patient was a 39-year-old female who had undergone mitral valve replacement 2 years previously. Staphylococcus epidermidis was detected on blood culture. Transesophageal echocardiography revealed vegetation attached to the left atrial site of the mitral prosthesis, whereas precordial echocardiography did not reveal any abnormal echo structure. The patient was performed an emergency operation, during which the echocardiographic finding was confirmed. We conclude that performance of transesophageal echocardiography is useful when clinical features suggest prosthetic valve endocarditis.

[Surgical treatment of the so-called "galloping type" small size carcinoma of the lung].

We experienced twelve cases of non-small cell carcinoma of the lung of the so-called "galloping type" small size carcinoma (less than or equal to 2 cm). Ten cases presented with mediastinal lymph node metastasis and two cases with distant metastasis. Solitary lymph node metastasis observed in almost half of the cases and lymph node metastasis in peculiar lymphatic regions (#3 a) seen in two cases, were the prominent characteristics of the lymphatic pathway dissemination showed by this type of cancer in advanced clinical stage. The prognosis was good, with 3 years and 5 years survival rate of 72.2% and 54.1% respectively. According to these results, we consider that, if the clinical stage is favorable, the surgical treatment must be indicated in all cases of these advanced small size carcinoma of the lung.

[Studies on so-called "postoperative erythroderma": report of four cases].

"Postoperative erythroderma", the pathogenesis of this disease have solved as graft-versus-host disease (GVHD) due to blood transfusion, is fatal and impossible to cure for the time being. Therefore the prevention against the disease is very important. One woman and three men who underwent an operation and blood transfusion at our department died of this disease. They fell into high fever on 11-13 days, erythroderma on 12-16 days, liver dysfunction on 14 days, and leukocytopenia on 17-19 days, after surgery and transfusion. Eventually, they all suffered from thrombocytopenia, diarrhea, renal dysfunction, and sepsis which led to death. The clinical course, macroscopic and microscopic findings of them coincided with those of GVHD. Since 1989, we have tried following methods for prevention of postoperative erythroderma: Reducing blood transfusion, especially fresh blood and fresh thrombocyte plasma, by using predeposited autologous blood, autologous washed erythrocytes collected from the operative area before and after extracorporeal circulation (ECC), concentrated residual blood from the ECC using a hemoconcentrater, and 1,500 rad of cobalt-irradiation of fresh blood, fresh thrombocyte plasma, and blood collected within 7 days prior to the transfusion. Postoperative erythroderma has not been experienced by introduction of these methods since 1989.