Acute Adenoviral Infection Elicits an Arrhythmogenic Substrate Prior to Myocarditis

BACKGROUND

Viral cardiac infection represents a significant clinical challenge encompassing several etiological agents, disease stages, complex presentation, and a resulting lack of mechanistic understanding. Myocarditis is a major cause of sudden cardiac death in young adults, where current knowledge in the field is dominated by later disease phases and pathological immune responses. However, little is known regarding how infection can acutely induce an arrhythmogenic substrate before significant immune responses. Adenovirus is a leading cause of myocarditis, but due to species specificity, models of infection are lacking, and it is not understood how adenoviral infection may underlie sudden cardiac arrest. Mouse adenovirus type-3 was previously reported as cardiotropic, yet it has not been utilized to understand the mechanisms of cardiac infection and pathology.

METHODS

We have developed mouse adenovirus type-3 infection as a model to investigate acute cardiac infection and molecular alterations to the infected heart before an appreciable immune response or gross cardiomyopathy.

RESULTS

Optical mapping of infected hearts exposes decreases in conduction velocity concomitant with increased Cx43Ser368 phosphorylation, a residue known to regulate gap junction function. Hearts from animals harboring a phospho-null mutation at Cx43Ser368 are protected against mouse adenovirus type-3-induced conduction velocity slowing. Additional to gap junction alterations, patch clamping of mouse adenovirus type-3-infected adult mouse ventricular cardiomyocytes reveals prolonged action potential duration as a result of decreased IK1 and IKs current density. Turning to human systems, we find human adenovirus type-5 increases phosphorylation of Cx43Ser368 and disrupts synchrony in human induced pluripotent stem cell-derived cardiomyocytes, indicating common mechanisms with our mouse whole heart and adult cardiomyocyte data.

CONCLUSIONS

Together, these findings demonstrate that adenoviral infection creates an arrhythmogenic substrate through direct targeting of gap junction and ion channel function in the heart. Such alterations are known to precipitate arrhythmias and likely contribute to sudden cardiac death in acutely infected patients.

Laparoscopic partial nephrectomy: initial experience and comparison to the open surgical approach

During an 18-month period, 6 laparoscopic partial nephrectomies were attempted, 4 of which were successful. The surgical technique was modified and improved between cases aided by new laparoscopic instrumentation, such as the argon beam coagulator and the 7.5 MHz. ultrasonic sector scanning system. In a retrospective comparison between laparoscopic and open partial nephrectomy, estimated blood loss was 525 ml. for the former versus 708 ml. for the latter procedure. However, operating time was more than 2 hours longer with the laparoscopic approach. The major advantages of the laparoscopic procedure appear to be a more rapid return to full diet, less postoperative pain and less requirement for parenteral narcotics. Despite the small size of this series and limited followup data, convalescence may be shortened by 4 weeks after laparoscopic partial nephrectomy. Patients with benign diseases of the kidney, especially with a duplicated collecting system, who require partial nephrectomy may be considered candidates for the laparoscopic approach. The advantages to the patient, however, may be offset by the technical demands on the surgeon.

Laparoscopic approaches to the treatment of intrinsic urethral weakness (type III stress urinary incontinence)

The treatment of intrinsic urethral weakness (Type III stress urinary incontinence) has traditionally been accomplished by the performance of a sling cystourethropexy or the placement of an artificial urinary sphincter. As experience with operative laparoscopy continues to increase, the possibility of performing these procedures from a laparoscopic approach becomes realistic. We report our experience with the laparoscopic performance of a sling cystourethropexy and placement of an artificial urinary sphincter in the canine model. On the basis of initial results, we believe these techniques are feasible in human subjects.

Laparoscopic nephrectomy in crossed fused renal ectopia

Operative laparoscopy offers the patient a minimally invasive alternative to open surgery. We have recently performed a laparoscopic nephrectomy of the upper moiety of a crossed fused renal ectopia. The procedure lasted approximately six hours, and the patient was discharged on postoperative day 3. He was able to resume normal physical activity in one week. This case demonstrates the advantages of minimally invasive surgery.

Distribution of intrapleural and intravenous Corynebacterium parvum in humans; 99mTc-, and 131I-labeled bacteria

The distribution of Corynebacterium parvum labeled with 131iodine or 99mtechnetium was studied in 17 patients with bronchogenic carcinoma. The labeled bacteria were given intravenously or intrapleurally and monitored by whole-body gamma tracking and samples of blood and urine. Even though the rate of physical decay is quite different for 131iodine and 99mtechnetium, the tracking time of labeled bacteria was limited to 24 h after injection for both radioactive isotopes. Technetium labeling was preferred because of greater imaging resolution and less radiation dose to the patient. Following intravenous administration, labeled C. parvum was found predominantly in the liver and spleen, and in a lesser amount in the lung. Radioactivity was confined to the pleural cavity after intrapleural injection. These results suggest the combined intravenous and intrapleural route of adjuvant immunosupportive agents such as C. parvum for operable lung cancer patients.

Analysis of a pathology review of patients with lung tumors

The rates of agreement and patterns of disagreement in the classification of lung tumors were evaluated for a pathology panel review of 476 patients with lung cancer. The panel review consisted of three independent diagnoses made in accordance with the criteria of the Working Party for Therapy of Lung Cancer. At least two of the three pathologists agreed as to the major cell classification in 94% of the patients. In 67% of the evaluations, there was agreement among the three pathologists. Small-cell carcinoma and epidermoid carcinoma were the most consistently evaluated classes, followed by adenocarcinoma and large-cell carcinoma. The poorly differentiated categories provided the greatest source of difficulty in discriminating among major histologic classes. For an initial diagnosis of large-cell carcinoma, 14% of the second classifications were poorly differentiated epidermoid carcinoma, and 20% were poorly differentiated adenocarcinoma. For an initial diagnosis of small-cell carcinoma, 11% of the second independent evaluations classified the carcinoma as other than small-cell. The most likely alternative diagnosis was large-cell carcinoma (5%).

Small-cell carcinoma of the lung--survival according to histologic subtype: a Veterans Administration Lung Group Study

Six-hundred-twenty cases of small-cell carcinoma of the lung entered into the Veterans Administration Lung Group protocols 9-15 were retrospectively subdivided into histologic subtype, as proposed by the WHO (1977). Medium survival was greater for subtype No. 21 (lymphocyte-like) than for subtype No. 22 (intermediate) (17.2 vs. 12.6 weeks; P = .005). Patients with extensive disease survived longer with subtype No. 21 than subtype No. 22 (14.5 vs. 10.9 weeks; P = .026). However, no median survival difference was seen with limited disease. Survival for subtype 21 was greater than No. 22 (P = .016) for patients with poor initial performance status (IPS; Karnofsky 70 or less); for ambulatory patients (IPS 80-100) a survival advantage was seen for subtype No. 21 compared with No. 22, but did not quite reach statistical significance (P = .09). Survival in subtype No. 21 was better than in subtype No. 22 (24.3 vs. 14.7 weeks; P = .001) when no weight loss (less than 10 pounds over the six-month period prior to therapy) was documented. However, with weight loss (greater than 10 pounds) survival in each subtype was similar.

Phase II study of high-dose methotrexate in the treatment of patients with non-small cell carcinoma of the lung: an Eastern Cooperative Oncology Group study

Twenty-eight patients with inoperable non-small cell carcinoma of the lung were treated with high-dose methotrexate with citrovorum factor rescue. One patient (4%) responded with a partial regression of the tumor. Three patients had severe or life-threatening complications: acute renal failure, acute shortness of breath, and bone marrow suppression, respectively. There is 98% confidence that the true response rate for this therapy is less than 20%. The results of this study demonstrate that high-dose methotrexate with citrovorum factor rescue, in the schedule utilized, is not effective in the treatment of patients with non-small cell carcinoma of the lung.

Prognostic factors for survival in patients with inoperable lung cancer

Seventy-seven prognostic factors were considered in an evaluation of more than 5,000 patients with inoperable bronchogenic carcinoma of the lung; these patients were entered on the Veterans Administration Lung Group protocols 9-15 (1968-78). Fifty prognostic factors for survival were identified, and their relative contributions to patient survival were considered. The three most important prognostic factors affecting survival were the Karnofsky initial performance status score, extent of disease, and weight loss in the previous 6 months. These factors denoted three general prognostic components: current physical status, current disease status, and prior physical status. Initial performance status was the dominant prognostic factor. Characterization of patient's function status with the use of the Karnofsky scale was preferred to a summarized scale or a dichotomization into ambulatory versus nonambulatory. The current practice of dichotomizing factors resulted in the loss of much prognostic information. Other factors, such as tumor size, histologic type, and institution, appeared to be important when considered alone. However, their contribution was relatively minor after a correction was made for the effects of initial performance status, extent of disease, and prior weight loss. Depending on these three prognostic factors alone, median survival varied between 6 weeks and over a year. Reporting of results without the consideration of such prognostic factors severly hampers any comparisons that may be made between investigations.