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Biomedical subjects

L Harrison

Publications and source records attributed to L Harrison.

At least 127 records · Page 7Linked to original sources
PubMed1989

Remote afterloading intraluminal brachytherapy in the treatment of rectal, rectosigmoid, and anal cancer: a feasibility study.

From 1981 to 1986, 28 patients (27 evaluable) were treated with intraluminal brachytherapy (ILBT) using a remote afterloading technique for persistent or recurrent anal, rectal and rectosigmoid cancers. Eighty-nine percent underwent previous surgery for colorectal cancer. Seventy-seven percent of the patients received external beam irradiation (ERT) as a part of the present treatment. Intraluminal brachytherapy was given with a 2 cm diameter cylinder and the dose per fraction ranged from 440 cGy to 840 cGy at 0.5 cm from the surface of the cylinder. Follow-up ranged from 1 to 74 months with a median of 12 months. Patients were divided into two groups. Group I consisted of 15 patients receiving elective ILBT; Group II: 13 patients with recurrent disease. Seventy-one percent of the patients in Group I and 39% of the patients in Group II achieved local control. The majority of patients tolerated treatment well with only transient reactions. However, three patients (11%) developed grade 3 (G3) complications requiring surgical intervention. Eight patients developed moderate complications--grade 2 (G2)--requiring only conservative treatment. This study has identified several factors which appear to influence the risk of developing complications with this combined treatment, using remote afterloading apparatus, among which are technique of previous external beam irradiation, treatment length, anatomical location, intraluminal brachytherapy fractionation, and total cumulative dose (ERT + ILBT). This experience suggests that intraluminal brachytherapy appears to be an acceptable form of treatment, as a boost to external beam radiation therapy, in the management of rectal and colorectal cancers.

Adult↗
PubMed1989

Treatment of primary unresectable carcinoma of the pancreas with I-125 implantation.

Between January 1 1974 and October 31 1987, 98 patients with biopsy proven unresectable adenocarcinoma of the pancreas were treated with I-125 implants during laparotomy. Presenting symptoms were pain (57 patients), jaundice (45 patients), and weight loss (34 patients). All patients underwent laparotomy and surgical staging. Thirty patients had T1NoMo disease, 47 patients had T2-3NoMo disease, and 21 patients had significant regional lymph node involvement (T1-3N1Mo). The surgical procedure performed was biopsy only (16 patients), gastric bypass (36 patients), biliary bypass (49 patients), and partial or total pancreatectomy with incomplete resection (5 patients). The total activity and the number of seeds used were determined from the Memorial Sloan Kettering Cancer Center (MSKCC) nomogram. Stereoshift localization X ray films were taken 3-6 days after operation. The mean activity, minimal peripheral dose (MPD), and volume of the implants were 35 mCi, 13,660 cGy, and 53 cm3, respectively. In addition, 27 patients received postoperative external irradiation and 27 patients received chemotherapy. Postoperative complications were observed in 19 patients. These included post-operative death (1 patient), biliary fistula (4), intraabdominal abscess (4), GI bleeding (3), gastric or small bowel obstruction (6), sepsis (5), and deep vein thrombophlebitis (4). Pain relief was obtained in 37/57 patients (65%) presenting with pain. A multivariate analysis showed that four factors significantly affected survival: T stage, N stage, administration of chemotherapy, and more than 30% reduction in the size of the implant on follow-up films. The median survival for the entire group was 7 months. A subgroup of patients with T1No stage disease who received chemotherapy survived 18.5 months. The indications for I-125 seed implantation in unresectable carcinoma of the pancreas are discussed.

Adenocarcinoma↗
PubMed1989

A study of repeatability of dietary data over a seven-year period.

A repeatability study of dietary intake has been carried out using 94 control subjects from a previously reported case-control study of diet and colorectal cancer. Dietary histories readministered on average seven years after an initial interview were used to estimate intake of various macro- and microdietary components. Comparisons of current intake with intake of seven years previously yielded good reliability for macrocomponents among subjects reporting no dietary change during the time period. Reliability was poorer for microcomponents and for subjects reporting a dietary change. Comparisons were also made between diet measured seven years previously with subjects' recall of that diet. It is concluded that current diet is at least as reliable a measure of past diet as that assessed by a questionnaire addressed to the past period.

Aging↗
PubMed1988

New catheter technique for recording left free-wall accessory atrioventricular pathway activation. Identification of pathway fiber orientation.

The ability to record accessory atrioventricular (AV) pathway activation consistently may be uniquely beneficial in improving pathway localization, identifying anatomic relations, and providing insight into unusual conduction properties. For the purpose of recording left AV accessory pathway activation, an electrode catheter was specially designed for use in the coronary sinus. The orthogonal catheter has three sets of four electrodes spaced evenly around the circumference. Electrograms were recorded at low gain (less than 1 cm/mV) between adjacent electrodes on the same set (interelectrode distance, 1.5 mm, center to center). This provides a recording dipole perpendicular to the atrioventricular groove to enhance recording of accessory pathway activation while minimizing overlapping atrial or ventricular potentials. The orthogonal electrode catheter was used in the electrophysiological study of 48 consecutive patients with 59 left AV accessory pathways. The catheter could be advanced along the coronary sinus beyond the site of earliest retrograde atrial activation in 49 of the 59 accessory pathways. Activation potentials were recorded from 45 of the 49 (92%) accessory pathways accessible to the catheter (5 of 5 anterior, 8 of 8 anterolateral, 15 of 16 lateral, 5 of 5 posterolateral, 5 of 5 posterior, and 7 of 10 posteroseptal). Accessory pathway potentials were validated by dissociating them from both atrial and ventricular activation by programmed-stimulation techniques. During surgery, accessory pathway potentials were identified from orthogonal catheter electrodes in the coronary sinus in 14 of 16 accessory pathways (12 patients). Epicardial mapping confirmed the location of the accessory pathway, and direct pressure over the orthogonal catheter electrode that recorded the accessory pathway potential resulted in transient conduction block in nine of the 14 accessory pathways. Orthogonal electrode maps of the coronary sinus identified an oblique course in 39 of 45 recorded accessory pathways. Thirty-two of 38 left free-wall accessory pathways were oriented with atrial insertion 4-30 mm (median, 14 mm) proximal (posterior) to the ventricular insertion. In the remaining six free-wall accessory pathways, the lateral excursion could not be determined because either only the atrial end of the accessory pathway was recorded or activation of multiple pathway fibers prevented tracking of individual strands. The seven recorded posteroseptal pathways exhibited accessory pathway potentials throughout an 8-18-mm (median, 10 mm) length of the proximal coronary sinus, but fiber orientation was difficult to determine.(ABSTRACT TRUNCATED AT 400 WORDS)

Atrioventricular Node↗
PubMed1987

Very-high-dose cisplatin with bleomycin infusion as initial treatment of advanced head and neck cancer.

Fifty-one patients with locally advanced squamous cancer of the head and neck (SCHN) were treated with up to three cycles of very-high-dose cisplatin, 187.5 mg/m2 (administered over five days) in hypertonic saline, and bleomycin infusion, 60 U/m2 (administered over five days), prior to definitive local therapy, in an attempt to improve complete remission (CR) and overall response rates. After chemotherapy, patients underwent surgery if the tumor was resectable for cure, (unless the operation involved total laryngectomy), and/or locoregional radiation therapy. Twelve patients (24%) achieved CR and 23 (45%) partial remission (PR) for an overall response rate of 69%. Thirty-nine of the 51 patients are evaluable following chemotherapy and locoregional treatment, and 28 (72%) have achieved disease-free status. Seven of these 28 (25%) have subsequently relapsed. Eleven of the 51 patients (22%) have died at median follow-up of 10+ months (3+ to 24+). Nausea and vomiting (94%) was the most severe acute toxicity. Myelosuppression was mild and nephrotoxicity was effectively prevented by the 3% saline diuresis. Bleomycin was withheld in 12 of 49 (24%) because of deterioration in pulmonary function tests. Ototoxicity in 12 of 49 (25%) and neurotoxicity in 19 of 49 (39%) were the most significant long-term toxicities. Very-high-dose cisplatin and bleomycin in this study was an effective chemotherapy regimen, but not more so than more conventional doses of cisplatin. Toxicity from both drugs was significant.

Adult↗
PubMed1986

Continuous intravenous heparin compared with intermittent subcutaneous heparin in the initial treatment of proximal-vein thrombosis.

We performed a randomized double-blind trial comparing continuous intravenous heparin with intermittent subcutaneous heparin in the initial treatment of 115 patients with acute proximal deep-vein thrombosis. Intermittent subcutaneous heparin as administered in this trial was inferior to continuous intravenous heparin in preventing recurrent venous thromboembolism. The subcutaneous heparin regimen induced an initial anticoagulant response below the target therapeutic range in the majority of patients and resulted in a high frequency of recurrent venous thromboembolism (11 of 57 patients, 19.3 percent), which was virtually confined to patients with a subtherapeutic anticoagulant response. In contrast, continuous intravenous heparin induced a therapeutic anticoagulant response in the majority of patients and a low frequency of recurrent events (3 of 58 patients, 5.2 percent; P = 0.024); the recurrences were limited to patients with an initial subtherapeutic anticoagulant response. The results of this trial establish the efficacy of intravenous heparin in the treatment of proximal venous thrombosis and suggest a relation between the effectiveness of heparin and the levels of anticoagulation achieved; such a relation could explain the observed failure of the subcutaneous regimen.

Acute Disease↗
PubMed1986

A short diet history for assessing dietary exposure to N-nitrosamines in epidemiologic studies.

A short diet history for use in assessing dietary nitrosamine exposure in epidemiologic studies has been developed by using data from a case-control study of diet and stomach cancer carried out in Ontario, Manitoba, and Newfoundland between 1979 and 1982. The method gives excellent correlations for seven dietary components with estimates based on a full diet history, and also performs well when tested on a different data set from a case-control study of diet and colorectal cancer carried out in Ontario and Alberta between 1976 and 1978.

Alberta↗