Neural-network-based classification of Space Acceleration Measurement Systems (SAMS) data via supervised learning.

This paper illustrates the applicability of neural networks in classifying events using Space Acceleration Measurement System (SAMS) data. Computer programs have been written in the MATLAB environment for the following purposes: automatic retrieval of SAMS data from NASA CDROM disks, computation of power spectral densities for SAMS data and construction of input patterns for the training of a multi-layer neural network (MNN). The MNN has been trained using the backpropagation learning algorithm and the SAMS data collected on the STS-50 Space Shuttle mission for three crew exercise events. It is found that the trained MNN is highly successful in classifying events. In addition, the performance of MNN is found to be better than that of the nearest neighbor classifier.

Differentiation between benign and malignant disease of the breast using digital subtraction angiography of the breast.

The authors have investigated digital subtraction angiography (DSA) for the differential diagnosis of breast lesions detected initially by mammography. Eighteen patients scheduled for biopsy first underwent digital subtraction angiography of the breast (DSAB). Criteria for malignancy included the presence of abnormal vessels and a "blush" in the area of the lesion. A total of 17 lesions are currently available for histopathologic correlation. Although this is a small series, the initial results of DSAB suggest its potential utility for differentiating between benign and malignant lesions.

The spectrum of radiation enteritis. Surgical considerations.

Radiation therapy, often used to treat gynecologic and urologic pelvic malignancies, has varying, adverse effects on the bowel. Radiation enteritis may occur from one month to 20 years after irradiation, and disabling symptoms may require surgery in 10 to 20 per cent of patients. From our experience with 20 patients who required surgery for radiation enteritis and who were followed for up to 20 years, we were able to identify three clinical groups. Patients in the first group need only medical treatment for their symptoms, and observation, whereas patients in the second group may present with acute, debilitating, life-threatening symptoms that may require emergency surgery. Patients in the third group have a long-standing history of intermittent bowel obstruction and/or enteric fistulas that are best treated with adequate nutritional support followed by timely surgical intervention.

Islet cell autotransplantation after pancreatectomy for chronic pancreatitis. Its limitations.

Of 12 patients operated on for intractable pain from chronic pancreatitis, only the three with adequate preoperative insulin reserve were selected to undergo islet-cell replantation after subtotal pancreatectomy. Fourteen, nine, and four months postoperatively, they require no therapy with insulin. Since most techniques for obtaining islet cells have been performed with normal pancreata, chronic pancreatitis was produced in ten dogs by ligating the main and accessory pancreatic ducts. These dogs 162.6 +/- 15.8 days later underwent total pancreatectomy. The scarred pancreatic fragments were dissociated with collagenase for 20 minutes in five dogs or subjected to two intermittent digestions of ten minutes in the other five dogs and were autotransplanted to the liver. One dog from each group became normoglycemic within one week of replantation, and their percent per minute decreases of serum glucose level were 2.72 and 3.46, respectively. Our experimental and clinical data suggest that (1) present techniques for dissociating fibrotic tissue are unsatisfactory and lead to a very low yield of islet cells; (2) postoperative assessment of islet-cell function involves complicated invasive procedures (portal and hepatic vein cannulation) to determine accurately the source of insulin; and (3) careful preoperative evaluation of beta-cell function is needed.

The value of endoscopic retrograde cholangiopancreatography in the surgical management of chronic pancreatitis.

Sixty-five patients had ERCP for evaluation of chronic pancreatitis. Twenty-six had surgery. Based on surgical and pathological correlation, ERCP was found to be useful in preoperative planning for the type of surgical treatment most appropriate for each individual case.

Surgical treatment of chronic pancreatitis. A review after a ten-year experience.

Seventy-five operative procedures were done in 63 patients to correct one or more complications of chronic pancreatitis. Operations included resection, pancreaticojejunostomy, choledochoduodenostomy, draining and/or excision of pseudocysts, sphincteroplasty, and bypass surgery for relief of duodenal obstruction. All patients were followed up for up to 10 years, with 22 being followed up longer than five years. Recurrent pancreatitis occurred in three patients after resection and in two after drainage procedures, but attacks were milder with only an occasional occurrence. Operative procedures to relieve specific complications of chronic pancreatitis provided good results. However, because internal drainage of pseudocysts associated with chronic pancreatitis was frequently accompanied by recurrence of symptoms, excision offered better results. When the pancreatic duct was dilated, good results were obtained by pancreaticojejunostomy. In the absence of dilation, after strict preoperative slection of patients, and in the presence of diffuse parenchymal fibrosis, subtotal pancreatectomy is the procedure of choice.

The morbidity and mortality of colostomy closure.

Restrospective analysis was done of 304 patients who underwent colostomy closure at Henry Ford Hospital between 1967 and 1977. A mortality of less than 0.3 per cent and a morbidity rate of 14 per cent, with an average hospital stay of 15 days, is hereby reported. Wound infection was the most common complication with an incidence of 9.5 per cent. Late complications during the study period were less than 3 per cent. In our experience, if and intraperitoneal closure technique with resectiona and anastomosis is used, colostomy closure can be a safe procedure with minimal mortality and morbidity. We believe colostomy closure should be considered as nothing less than a major colonic resection.

Pneumatosis intestinalis: a clinical classification.

Review of our experience with pneumatosis intestinalis has allowed identification of three major clinical groups of patients. In each of these groups, the etiology of pneumatosis intestinalis usually can be identified, and it frequently has an ominous prognosis. Treatment should be directed to the underlying condition when possible, and hence must be individualized. Those patients who would be categorized as Group I can simply be kept under observation. Patients in Group II might obtain relief from breathing increased concentrations of oxygen. For patients in Group III vigorous therapeutic measures generally are necessary to ensure survival. The increasing use of mechanically controlled ventilation and positive end-expiratory pressure may be contributing to the incidence of pneumatosis intestinalis. The ileus sometimes observed in these patients may accompany or precede the development of intramural air, a condition identifiable on roentgenographic examination. Awareness of the possible presence of intramural air may help in identifying patients who may not need operation. But even when roentgenographic examination has confirmed the presence of intramural air, abdominal exploration still may be necessary to rule out a diagnosis of perforated viscus. We hope that these concepts and our emphasis upon individualization of treatment may improve the prognosis for patients who have pneumatosis intestinalis.

The management of colonic and rectal injuries.

One hundred fifty cases of patients treated at the Henry Ford Hospital with traumatic injuries of the colon and rectum are reviewed. Five of 119 patients treated with exteriorization died, two of them from multiple visceral injuries, shortly after operation. The mortality rate for the primary-closure group of 24 patients was 8.3 per cent. In this group, 11 patients had postoperative complications. Thirty-nine of the 119 patients in Group II nad 62 complications. Infection was the predominant problem in both groups of patients. We still believe that exteriorization of the injured colon remains the safest method of managing these patients.

The spectrum of colonic involvement in pancreatitis.

Colonic involvement as a result of pancreatitis is an uncommon but interesting complication of the disease. Among the significant manifestations we have seen are: 1) adynamic ileus of the transverse colon, 2) fibrosing, stenosing pericolitis localized to the splenic flexure area, and 3) colonic hemorrhage secondary to necrosis and fistula formation. Ordinarily, conservative treatment will suffice, but in complicated cases, individualized surgical treatment becomes necessary.

Volvulus of the colon.

We have reviewed the records of 48 patients who had colonic volvulus. Volvulus occurred in the sigmoid colon in 27 (56%) and in the right colon in 19 (40%). Volvulus elsewhere in the colon is rare, requiring unusual anatomic circumstances of a long mesentery and a mobile colon. The clinical history is characterized by a long history of bowel dysfunction followed by an episode of acute intestinal obstruction. The patient is often aged and is plagued by mental disorders and a number of degenerative diseases. Distention of the abdomen is the most significant finding, and tenderness may indicate peritonitis due to ischemic changes in the bowel. Three-positional films of the abdomen are most valuable, showing great distention of the colon and air-fluid levels in the bowel with regularity. Barium-enema studies will more accurately reveal the site and nature of obstruction. The barium-enema examination must be done carefully. It is omitted when peritonitis is present. Operative treatment is necessary for volvulus of the right colon. Non-operative reduction is effective for nonstrangulating volvulus of the sigmoid colon as an emergency procedure. Sigmoidoscopic examination and insertion of a long rubber tube will give dramatic relief to a substantial number of patients. Operative intervention is necessary when conservative measures fail. When gangrene is found at operation, exteriorization resection of the colon may be life-saving. Elective resections are recommended for patients who are in otherwise good health in order to prevent recurrences. The mortality rate in this series of 48 cases was 12.5 per cent. Cecal volvulus was present in each of the six patients who died. Sepsis and cardiopulmonary diseases were common in patients who died.

Absence of pancreatic duct dilation in chronic pancreatitis: surgical significance.

Of 22 patients treated surgically for intractable pain from chronic alcoholic pancreatitis, eight did not show notable dilation of the main pancreatic duct by endoscopic retrograde cholangiopancreatography (ERCP), operative pancreatography, and/or operative and microscopical studies of the pancreas after subtotal pancreatectomy. In all patients, far advanced parenchymal pancreatitis was evident at operation and by microscopical study of the removed portion of the pancreas. These findings indicate that the basic problem in a considerable number of patients with symptomatic alcoholic chronic pancreatitis is not related primarily to obstruction with dilation of the major pancreatic duct, but to intrinsic changes in the parenchymal pancreas. The preoperative use of ERCP and individualization of operative procedures with a preference for subtotal or partial pancreatectomy for symptomatic chronic alcoholic pancreatitis are supported.

Entrapment of the colon following diaphragmatic injuries: report of eight cases.

With a rise in the incidence of severe injuries, we are seeing increasing numbers of patients with colonic entrapment occurring at the sites of diaphragmatic injuries. The initial injury might have occurred recently or it might have occurred as long as 25 years before. Blunt trauma, stabbings, and infection accounted for the initial trauma in our patients. Acute symptoms implicate the cardiorespiratory system as a result of interference with respiration and the filling and function of the heart. Acute or chronic gastrointestinal symptoms may suggest intestinal obstruction or functional bowel disorders. The proper diagnosis of colonic entrapment depends upon a high index of suspicion and proper studies. Chest x-rays, fluoroscopy, barium-enema examinations and contrast studies of the upper gastrointestinal tract are essential. Acute cardiorespiratory enbarrassment necessitates prompt surgical intervention. When subdiaphragmatic injuries are suspected, an abdominal incision is necessary. In long-standing cases where the abdominal viscera are intact, the thoracic approach is preferable. At times, the combined thoraco-abdominal incision may be preferable. Diaphragmatic injuries resulting in colonic entrapment occurred most often in the left hemidiaphragm, which is relatively unprotected. In seven of our eight patients, the left diaphragm was the site of herniation. The liver on the right side serves to protect this area from herniation. Only the largest defects permit displacement of the liver into the right chest. Only one of our patients had such a defect. Patients with long-standing cardiac or gastrointestinal symptoms suggestive of colonic entrapment should have a THOROUGH MEDICAL evaluation before any operative treatment is advised. We have reviewed the cases of eight patients in whom infection, stabbings and blunt trauma resulted in diaphragmatic herniations with subsequent colonic entrapment. The splenic flexure of the colon protruded through the defect in three of our eight patients. The transverse colon was located above the diaphragm in five.