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Biomedical subjects

S E Hedberg

Publications and source records attributed to S E Hedberg.

At least 19 recordsLinked to original sources
PubMed1998

A software sensor using neural networks for detection of patient workload.

The morphology of intracardiac electrograms (IEGMs) was used for pacemaker patient workload estimation. The body posture also was studied as another characteristic. The IEGMs were obtained and recorded via temporary transcutaneous leads connected to the implanted pacemaker. IEGMs were recorded during exercise and at rest. Recordings at rest were performed in different body positions. The morphology was analyzed visually in order to observe changes due to workload and posture. The recordings were digitized and processed by a computer-simulated neural network. The network was used as an automatic IEGM classifier based on the morphology. Our results show that the morphology of the IEGM may be used as an indicator of patient workload and body posture. The necessary information is found mainly in the ST segment. We conclude that neural networks seem to be useful in an active cardiac device.

Aged↗
PubMed1987

Postoperative radiation therapy of rectal cancer.

Beginning in December 1975, at the Massachusetts General Hospital (MGH) patients with rectal carcinomas thought to be at high risk of local recurrence after potentially curative surgical resection, were entered on a treatment protocol of high dose postoperative radiation therapy. Treatment was given with X rays of 10 MeV, generally using a four-field box technique to a dose of 4500 cGy with a boost to 5040 cGy or higher when the small bowel could be excluded from the reduced field. One-hundred sixty-five patients who began their radiation therapy between December 1975 and December 1982 were entered into the study. The median age was 65 years. The median follow-up in the survivors was 56 months, with a minimum follow-up of 17 months. All but 10 patients were followed for more than 2 years. Of the entire group, the actuarial 5-year survival was 53%, with survival of 71% in patients with Stage B-2, 39% in Stage C-2, and 17% in Stage C-3. Local failure was seen in 5/53 patients with Stage B-2 disease and 0/7 of patients with Stage B-3 disease. In patients with positive lymph nodes, local failure occurred in 2/10 (20%) of patients with Stage C-1, 16/77 (21%) of Stage C-2, and 8/15 (53%) of patients with Stage C-3 disease. Compared to previous series of surgery alone, the local failure rate has been decreased by more than one-half in all patients, except those with Stage C-3. Efforts to maximize the radiation doses in all stages should be made to minimize local failure. For Stage C-3, newer strategies such as intraoperative radiation therapy should be employed to decrease the continuing high incidence of failures.

Aged↗
PubMed1986

Intraoperative electron beam radiotherapy in the treatment of unresectable rectal cancer.

We treated 29 patients who had primarily unresectable rectal cancer with an aggressive combined surgical and radiotherapeutic approach. Each patient received 5,040 rad of preoperative external beam radiation therapy. Eighteen patients responded adequately to allow resection of all macroscopic tumor; 11 patients underwent resection but had residual cancer in the pelvis. A single bolus of 1,000 to 2,000 rad of intraoperative electron beam radiation was given. Follow-up time ranged from three to 66 months, with a median of 43 months for living patients. The actuarial local control rate at 36 months for the entire group was 87%. In the group of 18 patients who underwent resection, the local control rate was 92%, with a three-year survival rate of 70%. Our results are considerably improved over our prior experience without intraoperative radiation therapy--a 57% local control rate and a 30% three-year survival rate.

Actuarial Analysis↗
PubMed1985

Objective evaluation of ampullary stenosis with ultrasonography and pancreatic stimulation.

Ultrasonography can detect changes in pancreatic and bile duct sizes after pancreatic stimulation by secretin or morphine and prostigmine. The effects of the two pharmacologic regimens on pancreatic duct dilatation were comparable and correlated with papillary stenosis determined at surgery, but the morphine and prostigmine combination produced more false-positive responses than did secretin. After administration of intravenous secretin (1 unit/kg), the pancreatic duct dilated in 83 percent of 12 symptomatic patients found at surgery to have a stenotic sphincter of Oddi and in 72 percent of 17 symptomatic patients found to have a stenotic accessory papilla associated with the pancreas divisum anomaly. Comparable dilatation occurred in 14 percent of 14 control subjects without suspected ampullary disease and in none of 10 patients with surgically disproved stenosis (p less than 0.001). The morphine and prostigmine combination produced more false-positive results in both the pancreatic duct and bile duct. Concomitant elevation of the serum amylase level and reproduction of pain were found to be of no discriminatory value. In patients whose pancreatic duct dilated preoperatively during secretin stimulation, dilatation did not occur after surgical sphincteroplasty. A positive test result was associated with a 90 percent success rate in preventing recurrent pancreatitis and ameliorating pain. A negative test result was associated with a 29 percent success rate. Ultrasonography of the pancreatic duct with secretin stimulation may provide objective criteria to supplement clinical judgment in selecting patients for sphincteroplasty to treat stenosis of either the sphincter of Oddi or the accessory papilla in pancreas divisum.

Ampulla of Vater↗
PubMed1985

Colonic polyps.

Carcinoma of the large bowel arises almost exclusively in neoplastic polyps, which are present in 5-10% of the population over age 40. These polyps may be of three histologic types: (a) tubular adenoma (adenomatous polyp), (b) tubulovillous adenoma (villoglandular polyp), and (c) villous adenoma. The tendency for malignant change is greatest in the villous adenoma (41%) and in tubulovillous (villoglandular polyps--23%). In tubular adenomas (simple adenomatous polyps), the incidence of malignancy is 5% over all. The tendency toward malignant change is determined by histologic type, size, and degree of atypicality of adenoma. Early detection and complete removal of neoplastic polyps of the colon are essential to the prevention of cancer of the large bowel, and this may usually be done in most cases with the colonoscope.

Adenoma↗
PubMed1985

Injection thrombosclerosis of esophageal varices.

It is now evident that injection sclerotherapy is a fast, effective method for controlling the acute variceal bleed. The results of sclerosis for control of acute variceal hemorrhage have been reported by many, including ourselves, and control rates vary from 78.0 to 95.0 per cent. Herein, we report a control rate of 94.7 per cent and a rebleeding rate of 22.0 per cent using a technical variation of sclerosis therapy. Thrombosclerosis is used soon after admission to the emergency room as a first line treatment to control variceal bleeding, often in lieu of the Sengstaken tube. Follow-up injections are scheduled at increasing intervals to achieve definitive control of the varices and are an essential feature of sclerotherapy as a management option.

Acute Disease↗
PubMed1984

Angiodysplasia. Clinical presentation and colonoscopic diagnosis.

Angiodysplasia is a recently recognized important cause of lower intestinal bleeding in older patients. Although angiography is an established procedure for the diagnosis of angiodysplasia, colonoscopy is being used increasingly for evaluation of lower intestinal bleeding. In order to define the nature of bleeding due to angiodysplasia and the appropriate role of colonoscopy, 80 patients diagnosed by angiography, pathology, or colonoscopy were reviewed. Bleeding attributable to angiodysplasia varied from acute life-threatening hemorrhage to occult blood in stools. Thirteen patients with angiodysplasia had no bleeding and were identified incidentally by colonoscopy performed for other indications. Eighty-nine percent of the lesions were located in the right colon and there was a mean of 1.5 angiodysplastic lesions per patient. The sensitivity of colonoscopy compared to angiography and pathology was 68% overall and 81% when the colon was completely examined and lesions were located in the colon. The predictive value of a positive colonoscopic diagnosis was 90% in this population. Colonoscopy should be employed as an initial study in patients with chronic or mild acute rectal bleeding.

Acute Disease↗
PubMed1984

Complications of intraoperative radiation therapy.

The ability to demonstrate an improvement in therapeutic ratio is critical in assessing new treatment modalities; an evaluation of treatment complications is essential for this purpose. We have studied the severe complications occurring after treatment with intraoperative radiation therapy (IORT) in patients with locally advanced carcinoma of the rectum. Four groups of patients were compared: Group 1 (80 patients) had treatment with surgery alone for mobile and resectable tumors; Group 2 (23 patients) had treatment with high dose preoperative irradiation followed by surgical resection for tumors which were fixed to adjacent structures and initially unresectable for cure; Group 3 (24 patients, primary disease) and Group 4 (17 patients, locally recurrent disease) had locally advanced tumors as in Group 2 but were treated with IORT after preoperative irradiation and attempted surgical resection. All but 3 complications occurred within one year of therapy. Severe complications were seen in 16% of patients in Group 1, 35% in Group 2, 21% in Group 3 and 47% in Group 4 (32% in Groups 3 and 4 combined). There was a statistically insignificant increase (p = .10) in the complication rate in all irradiated patients (locally advanced tumors) compared to surgery alone (clinically mobile tumors). These data indicate no increase in severe complications with the use of IORT. If the ongoing studies continue to show improved local control with the use of IORT, expanded use of this modality may be warranted.

Adult↗
PubMed1983

Low-dose preoperative irradiation, surgery, and elective postoperative radiation therapy for resectable rectum and rectosigmoid carcinoma.

A regimen of low-dose preoperative radiation therapy (RT), surgery, and elective postoperative RT for resectable carcinomas of the rectum and rectosigmoid is presented. Initial results in a group of 36 patients is discussed. In four patients clinically silent metastatic disease was discovered. Of 16 patients without indications for postoperative RT, only one died with disease. Indications for postoperative irradiation were found in 15 patients and four relapses (26%) subsequently occurred. Since the surgicopathologic stage of the tumor is the best prognostic predictor for rectal cancer, this regimen allows for the delivery of high-dose adjuvant irradiation only to those at high risk of local recurrence. Thus, this combination selects patients likely to benefit from postoperative RT while preserving the advantages of preoperative RT.

Female↗
PubMed1983

Residual, unresectable, or recurrent colorectal cancer: external beam irradiation and intraoperative electron beam boost +/- resection.

While combinations of external beam radiation (XRT) and surgery decrease pelvic recurrence and improve survival in the subgroups with residual disease (postop XRT) or initially unresectable disease (preop XRT), local recurrence is still unacceptably high, and survival could be improved. In view of this, pilot studies were instituted at Massachusetts General Hospital in which 32 patients received the standard previous treatment of external beam irradiation and surgery but in addition had an intraoperative electron beam boost of 1000-1500 rad to the remaining tumor or tumor bed. For the 16 patients who presented with unresectable primary lesions, the addition of intraoperative radiotherapy has resulted in a total absence of local recurrence with a minimum 20 month follow-up, and survival rates are statistically better than for the previous group treated with only external beam irradiation and surgical resection. In the group with residual disease, again there have not been any local recurrences in the 7 patients who received all treatment modalities versus 54% and 26% for the group with gross and microscopic residual treated with only external beam techniques. The remaining 9 patients presented with recurrent unresectable lesions--3 are alive (2 NED) at greater than or equal to 3 years.

Colonic Neoplasms↗
PubMed1982

Injection sclerotherapy of esophageal varices using ethanolamine oleate.

Fifty-three patients with upper gastrointestinal bleeding and proven esophageal varices were treated by intravascular injection sclerotherapy of the varices using a mixture of ethanolamine oleate, bovine thrombin and cephalothin. An intraesophageal balloon was used to impede craniad flow during the injection. Except in three patients who failed to stop bleeding from nonvariceal lesions, sclerotherapy was 94 percent successful in controlling bleeding. The mortality rate in sclerotherapy patients with ascites was 25 percent compared with 54 to 75% reported elsewhere. There has been no rebleeding from varices after the third treatment week in patients followed up for up to 14 months.

Ascites↗
PubMed1977

Failure of complete bile diversion and oral bile acid therapy in the treatment of homozygous familial hypercholesterolemia.

Two patients with nomozygous familial hypercholesterolemia, refractory to medical therapy, underwent complete bile diversion by common-duct ligation and cholecystostomy, in an attempt to arrest the progression of their xanthomatosis and atherosclerosis by depletion of body cholesterol. Clofibrate was given after operation to one patient, and cholic acid to both, in an effort to enhance further the negative sterol balance. Bile diversion produced an increase of six to eight times in gastrointestinal sterol output, which was not increased further by either clofibrate or cholic acid therapy. Despite a calculated sterol loss of 560 g over 14 months in one patient and 400 g over 10 months in the other, neither plasma cholesterol nor xanthoma size decreased. Continuity of the biliary tree was therefore restored. The data suggest that patients with homozygous familial hypercholesterolemia respond to even massive gastrointestinal sterol depletion with equal increases in sterol synthesis.

Administration, Oral↗