תוצאת חיפוש

Prediction of Physiological Response from Mathematical Models 

Yoram Epstein, Yuval Heled, Daniel Moran, Yair Shapiro

Institute of Military Medicine, Medical Corps, Israel Defense Forces and Heller Institute of Medical Research, Sheba Medical Center, Tel Hashomer

The ability to predict the physiological responses of workers exposed to extreme environmental conditions, has been a challenge to environmental physiologists for more than 3 decades. Therefore, mathematical models have been developed to predict metabolic rate under various levels of work intensity and dynamic changes in body temperature and heart rate.

Based on the effect of exercise on the cardiovascular system, a model was developed to predict mean arterial blood pressure as a function of heart rate. Physiological strain could also be estimated on the basis of thermoregulatory and cardiovascular strains.

This paper summarizes knowledge accumulated during 25 years of studies in the field of mathematical modeling of physiological parameters. Besides analyzing the logic underlying each model, it explains the scientific approach in developing a model from its early concept to the model's application in the field.

Thallium Scan and Pulmonary Carcinoma 

Adam Mor, Amit Segev, Rami Herskoviz, Yoseph A. Mekori

Dept. of Medicine B, Meir General Hospital, Kfar Saba Affiliated with Sackler Faculty of Medicine, Tel Aviv

A 70-year-old man was admitted for exacerbation of congestive heart failure. In his assessment thallium scan of the heart was performed. An incidental finding was a focus of absorption in the right lung. The lesion was later diagnosed as adenocarcinoma based on the cytological findings.

1000 Cardiac Catheterizations in Congenital Heart Disease

Benjamin Zeevi, Galit Bar-Mor, Michael Berant

Cardiac Catheterization Unit, Schneider Children's Medical Center, and Sackler School of Medicine, Tel Aviv University

Over the past 15 years, percutaneous therapeutic cardiac catheterization has become increasingly important in the treatment of congenital heart disease. We describe our experience in 1000 such catheterizations between 1993-1997. 55% were in 1-12-year-olds; only 20% were in patients younger than 1 year old and 11.3% were in adults with congenital heart defects. In about 50% it was at least a second cardiac catheterization. Overall, there were 425 therapeutic cardiac catheterizations, increasing from 33% in the first 200 procedures, to 63% in the last 200.

We performed 30 different types of therapeutic catheterizations: 23.3% were valvular dilations, 21.4% vessel angioplasties, 36.9% closure procedures, 9.2% electrophysiological procedures, and 9.2% miscellaneous. In 31.3% of therapeutic catheterizations we used 12 new procedures. Minor complications occurred in 8.5% and major in 0.6%; most complications were successfully treated or were self-limited and there was no residual damage.

In this report the current role of each type of major catheterization is discussed on the basis of our experience. Further development of technology for lesions not amenable to currently available transcatheter methods, and longer follow-up for current techniques will consolidate the role of therapeutic cardiac catheterization in congenital heart disease.

Malignant Lymphoma of the Bladder

Y. Mor, Z. Dotan, J.H. Pinthus, I.S. Engelberg, J. Golomb, J. Ramon

Depts. of Urology and Pathology, Chaim Sheba Medical Center, Tel Hashomer

Urinary tract lymphoma is usually reported when the secondarily stem is affected by widespread non-Hodgkin lymphoma. We describe an 83-year-old woman who presented with secondary lymphoma of the bladder 3 years after diagnosis when it initially infiltrated her breast. Treatment included local transurethral excision followed by chemotherapy, during which she died of disseminated disease.

Liver Surgery - Five Years of Experience

Franklin Greif, Moshe Rubin, Eitan Mor, Israel Nudelman, Arnold Sihon, Arie Figer, Alex Belinki, Shlomo Lelcuk

Hepatobiliary Unit and Depts. of Surgery B, Transplantation, Oncology and Radiology, Rabin Medical Center (Beilinson Campus) and Sackler School of Medicine, Tel Aviv University

Major hepatic resections have been associated with significant morbidity and mortality. In the past decade or so this has changed and such procedures are now done in increasing numbers. In the past 5 years we operated on 129 patients with benign or malignant hepatic lesions (75 females, 54 males; age-range 14-84). the reason for surgery was malignancy in 94 (72.9%) and benign lesions in 35 (27.1%). The most common indication for surgery was liver metastases secondary to colorectal cancer in 45% of all patients or 61.7% of those operated for malignancy. Primary liver cancer was the cause for liver resection in 13.2% of all patients or 18.1% for those with malignancy. Of the 35 patients with benign lesions the leading causes for surgery included: giant cavernous hemangioma, simple liver cysts, echinococcus cysts and focal nodular hyperplasia (11%, 22.8%, 20% and 14.3%, respectively).

76 patients underwent anatomical resection and 63 had either a nonanatomical resection or a different operation. Among the former the most common procedure was right hepatectomy (36) and among the later a nonanatomical resection equal to 1-3 Couinod segments (44). Operating time ranged from 55 min. to 8:41 hours with a mean of 3:31‏1:37. Mean hospital stay was 8.7‏5.8 days and 86.8% received between 0-2 units of blood. Overall mortality was 6.2% and 31.2% of the fatalities had cirrhosis. Overall mortality in noncirrhotic patients was 2.6%. The complication rate was 16.3% and only 7 patients (4.4%) were hospitalized in the intensive care unit. This indicates that major liver resections can be done safely, with morbidity and mortality similar to that of other major abdominal operations. 

Balloon Angioplasty of Native Coarctation of the Aorta

Benjamin Zeevi, Galit Bar-Mor, Michael Berant

Cardiac Catheterization Unit, Schneider Children's Medical Center, Petah Tikva, and Sackler School of Medicine, Tel Aviv University

The use of balloon dilatation to treat native coarctation of the aorta is gaining acceptance among interventional pediatric cardiologists, but is still controversial. We describe our experience with this procedure in 21 children, mean age 5.6 years and mean weight 21.1 kg. Most had an additional congenital heart defect, most commonly a bicuspid aortic valve. 17 were asymptomatic, 3 had tachypnea and 1 infant had severe congestive heart failure and was ventilated. The mean systolic blood pressure was 129.7 mm Hg.

Balloon dilatation was successful in 90% (19), decreasing the mean maximal systolic gradient from 35.3 to 9 mm Hg (p<0.001), and increasing the narrowest area from 3.9 to 8.2 mm (p<0.001), with a mean balloon-to-coarctation width-ratio of 2.8. There were no complications. Of 15 who underwent repeat cardiac catheterization at a mean interval of 10.6 months, 2 had a maximal systolic gradient of more than 20 mm Hg. 1 of these underwent successful repeat angioplasty and the other, who also had a small aneurysm, underwent surgical repair successfully. 2 others had small aneurysms and they are being followed clinically.

All patients were seen again after a mean interval of 31 months. The mean systolic blood pressure was 104 mm Hg, significantly lower than before intervention (p<0.002). 1 had an increased pressure gradient between right arm and leg of 35 mm Hg at later follow-up, and repeat cardiac catheterization demonstrated a good result 13 months after the initial procedure. She is awaiting a third catheterization. Overall, 90% had good mid-term results.

Based on our experience and recent reports, balloon angioplasty is safe and effective in most children older than 7 months and should be considered a viable alternative to operation for discrete aortic coarctation. Further long-term evaluation is needed.

Percutaneous Closure of Patent Arterial Ducts with Occluding Spring Coils

Benjamin Zeevi, Galit Bar-Mor, Michael Berant

Cardiac Catheterization Unit, Schneider Children's Medical Center, Petah Tikva and Sackler School of Medicine, Tel Aviv University

In recent years percutaneous closure of small and medium- sized patent arterial ducts has been achieved using occluding spring coils. We describe our experience in 93 patients with this tec, using a snare to facilitate the procedure in most. All patients had a clinically apparenpatent arterial duct and had undergone attempts at transcatheter closure at a mean age of 6.8 years. In 1, the duct was a residual lesion following surgical ligation, and in 5 it was a residual following attempted closure with the Rashkind double-umbrella. The mean narrowest diameter of the ducts was 2.1 mm.

In our 93 patients implantation was successful in 92 (99%), using 1 coil (82 patients), or 2 (10 patients), and in 1 by a combination of a double-umbrella device and an occluding spring coil.

The mean fluoroscopic screening time for the whole group was 22.8 minutes, which decreased to 16.8 minutes in the last 50 patients. The coil embolized in 7 patients, but was retrieved in 6 and the ducts were subsequently occluded with another coil. In 1 patient the coil was left in a distal small branch of the left pulmonary artery and the duct was successfully occluded with a double-umbrella.

Color-Doppler echocardiogram performed the morning after placement of the coils showed residual leaks in 18%. At mean follow-up of 24.6 months repeat imaging showed residual leaks in only 3 of these patients (3%).

We conclude that occlusion of small to medium-sized ducts using coils appears to be effective and is the treatment of choice. The use of a snare to hold and manipulate the coil as it is delivered improves control of the coil, the accuracy of its placement, as well as giving complete occlusion of the ducts.

Intestinal Transplantation: World Experience and Future Perspective

Eytan Mor, Moshe Rubin, Yaron Niv

Depts. of Transplantation, Surgery B and Gastroenterology Institute, Rabin Medical Center, Beilinson Campus, Petah Tikva

Intestinal transplantation, which until recently has been considered an experimental procedure, is now undergoing considerable change and becoming a standard treatment for patient with intestinal failure. The major improvement in results is due to the introduction of new immunosuppressive agents that have led to significant reduction in acute rejection. Nevertheless, reduction in severe infectious complications, which are the main cause of mortality after transplant, as well as improved techniques for early diagnosis of rejection are needed before intestinal transplantation can be widely used.

We describe our experience in post-transplant follow-up of a woman, aged 32-years, who had undergone intestinal transplantation for short bowel syndrome after extensive bowel resection.

The Mitrofanoff Pouch in Lower Urinary Tract Reconstruction

J.H. Pinthus, Y. Mor, J. Ramon

Urology Dept., Chaim Sheba Medical Center, Tel Hashomer

The Mitrofanoff principle, first described in 1980, consists of implanting a tubular organ such as the appendix, ureter, or fallopian tube into the wall of the bladder (or urinary reservoir) to create a non-refluxing, catherizable urinary conduit. Between 1993-1996, 7 men and 1 woman (aged 48-64, average 59) underwent radical cystectomy and urethrectomy combined with the creation of a MAINZ I urinary reservoir (based on the Mitrofanoff principle). In men the indication for the procedure was the diagnosis of invasive transitional cell carcinoma of the bladder with involvement of the prostatic urethra. All patients had refused urinary diversion to an ileal conduit because of its deleterious effect on the quality of life.

In all patients the postoperative course was uneventful, apart from intraperitoneal urinary leakage from the reservoir in 1, successfully managed conservatively. The patients have gained full control of urinary drainage, performing intermittent self-catheterizations every 4-5 hours. In 3 patients there were difficulties with catheterization due to stenosis of the conduit, usually at the skin level. None have suffered leakage from the reservoir, during the day, even when it was full.

Our experience shows that creation of a continent urinary reservoir according to the MAINZ I technique is an excellent surgical solution for patients in whom the creation of an orthotopic reservoir is impractical. The use of the umbilicus as a stomal site preserves normal body image and thus does not interfere with quality of life as in those undergoing radical cystectomy.

Transcatheter Closure of Atrial Septal Defect

Benjamin Zeevi, Michael Berant, Rami Fogelman, Galit Bar-Mor, Leonard Blieden

Cardiology Institute, Schneider Children's Medical Center, Petah Tikva and Sackler School of Medicine, Tel Aviv University

Isolated secundum atrial septal defect is one of the most common congenital heart defects. Surgical closure is the treatment of choice but is associated with a chest scar, some morbidity and a relatively long recovery and the use of cardiopulmonary bypass. Transcatheter closure of secundum atrial septal defect is therefor an attractive approach.

3 children, aged 5-10 years, underwent successful transcatheter closure of moderate to large central atrial septal defects with the Cardioseal device. The procedures were performed under x-ray and transesophageal echocardiographic guidance.

Our initial experience, and that of others, indicates that transcatheter occlusion of secundum atrial septal defects is safe and effective and can be an appropriate alternative in approximately 60% of patients.

Kimura's Disease and Angio- Lymphoid Hyperplasia

Henia Lichter, Karol Segal, Celia Mor, Raphael Feinmesser

Depts. of Ophthalmology, Otolaryngology and Pathology, Rabin Medical Center (Beilinson Campus), Petah Tikva, and Sackler Faculty of Medicine, Tel Aviv University

Kimura's disease is a rare angiolymphoid proliferative disorder of soft tissue characterized by subcutaneous swelling and a predilection for the head and neck. There are usually enlarged regional lymph nodes, eosinophilia and elevated sedimentation rate and IgE levels. A 26-year-old women with subcutaneous masses in the submandibular area is reported. The diagnosis of Kimura's disease versus angiolymphoid hyperplasia is discussed.

Living-Related Liver Transplantation

N. Bar-Nathan, Z. Shapira, E. Shaharabani, A. Yussim, Y. Ben-Ari, T. Sheinfeld, I. Zehavi, R. Shapira, G. Dinari, Z. Ben-Ari, R. Tur-Kaspa, E. Mor

Dept. of Transplantation and Liver Institute, Rabin Medical Center (Beilinson Campus), and Pediatric Intensive Care and Pediatric Gastroenterology Units, Schneider Children's Medical Center, Petah Tikva

Our experience with living-related liver transplantation is described. In 2 boys and 1 girl, aged 4-4.5 years with acute, fulminating hepatitis A, the presence of very severe jaundice (bilirubin levels > 18 mg%) associated with severe coagulopathy (INR>10) and encephalopathy indicated the need for urgent liver transplantation. In all 3 cases the left lateral hepatic segment of a matched blood type parent was transplanted. None of the donors suffered a serious complication postoperatively and all returned to full activity in 6-16 weeks. The post-transplantation course was uneventful in 1 child, but in the other 2 there was hepatic arterial thrombosis in 1 at 1 day and in the other at 8 days post-transplantation. Early detection of arterial thrombosis by Doppler sonography permitted salvage of the 2 hepatic grafts after thrombectomy and re-anastomosis. In 1 of these 2 children an anastomotic biliary stricture was found 2 months after transplantation. It was corrected at surgery and a percutaneous stent was inserted. All 3 children are alive with normal graft function at 2, 7 and 8 months post-transplantation, respectively. This initial experience indicates that living-related liver transplantation is feasible in Israel. The technique might help to solve our severe organ shortage for children awaiting liver transplantation.

Skeletonized Internal Mammary Arteries for Coronary Bypass Grafting

Jacob Gurevitch, Yosef Paz, Menachem Matsa, Amir Kramer, Dimitri Pevni, Oren Lev-Ran, H. Locker, Raphael Mohr

Dept. of Thoracic and Cardiovascular Surgery, Sourasky-Tel Aviv Medical Center

The skeletonized internal mammary artery (IMA) is longer, and its immediate spontaneous blood flow is greater than that of the pedicled IMA, thus providing increased versatility for complete, arterial myocardial revascularization without the use of saphenous vein grafts. From April 1996 to May 1997, 583 patients underwent coronary artery bypass grafting here and in 415 (71%) complete arterial revascularization was achieved using bilateral skeletonized IMA. The right gastroepiploic artery was used in 57 (13%); there were 329 males (79%) and 86 women (21%); average age was 64 (30-87) and 175 (36%) were older than 70; 131 (32%) were diabetics. Average number of grafts was 3.2 (range 2-6 grafts). At 30 days, 5 (1.2%) had died and there had been 6 perioperative infarcts (1.4%), 5 CVA's (1.2%), and 6 had sternal wound infections (1.4%). Up to 1-12 months of follow-up was achieved in 409 (99%). Late mortality was 1.4% (of which 3 were noncardiac). 394 (97%) were angina-free at latest follow-up. We conclude that arterial revascularization using bilateral skeletonized IMA is safe, as postoperative morbidity and mortality are low, even in old and diabetic patients.

Budd-Chiari Syndrome

S. Goland, S.D.H. Malnick, L. Shvidel, E. Mor, Z.M. Sthoeger, E. Evron

Medical Depts. C and B, and Hematology Institute, Kaplan Hospital, Rehovot; and Surgical Dept. B, Rabin Medical Center, Beilinson Campus, Petah Tikva

Budd Chiari syndrome is a rare disorder resulting from occlusion of hepatic venous drainage by hepatic vein thrombosis or by a membranous web in the inferior vena cava. In western countries the commonest causes are myeloproliferative disorders and hypercoagulable states. Presentation may be acute with rapid accumulation of ascites and hepatic failure, or subacute with symptoms developing over a few months. A chronic progressive form has also been described. On presentation there is usually abdominal pain, ascites, and hepatosplenomegaly; hepatic encephalopathy is found in about a third. Noninvasive, ultrasound-Doppler is recommended in diagnosis, and has a high correlation with hepatic venography. Liver biopsy is required for therapeutic decisions. Those with advanced hepatic failure or severe fibrosis on liver biopsy are referred for hepatic transplantation. When biopsy shows only hepatic congestion and inflammatory infiltrates, portosystemic shunting is recommended. We present a 61-year-old woman with ascites and hepatosplenomegaly that had developed over the courses of a few months. Budd-Chiari syndrome with chronic myelofibrosis and congenital protein C deficiency were diagnosed. Portosystemic shunt was performed but death from sepsis followed shortly.

Liver Allografts from Donors older than 60: Benefits and Risks

Eytan Mor, Dan Shmueli, Ziv Ben-Ari, Nathan Bar-Nathan, Ezra Sharabani, Alexander Yussim, Boris Dorfman, Ran Tur-Kaspa, Zaki Shapira

Transplantation Dept. and Institute of Liver Diseases, Rabin Medical Center, Beilinson Campus; and Sackler School of Medicine, Tel Aviv University

With limited organ resources and an increasing number of candidates for liver transplantation, the world-wide trend is towards using liver allografts from donors older than 60 years. This strategy, however, may be hazardous because of the known correlation between advanced donor age and graft dysfunction. Since January 1996, each of 5 patients received a liver allograft from a donor older than 60 years. Preservation time in these cases was shortened as much as possible and liver allografts were used only if there were no other potential risk factors for primary nonfunction. Mean cold ischemic time was significantly shorter in this donor group (7.8 hrs) than for livers from 28 younger donors (10.2 hour; p<0.01). 3 of the 5 grafts from older donors had normal function immediately. The other 2 initially had biochemical features of preservation injury, but graft function returned to normal within the first week after transplantation. All 5 patients currently have normal graft function, with follow-up ranging from 3-8 months. There was no difference between the 5 recipients of grafts from older donors and 28 adult recipients of grafts from younger donors in extent of preservation injury and in immediate graft function. We conclude that in countries with limited organ resources, such as Israel, liver allografts from older donors can be used within defined limits and minimal preservation time.