Radiotherapy in the management of pancreatic islet cell tumors

Malignant islet cell tumors are commonly treated with surgical resection. Chemotherapy is reserved for residual, unresectable, or metastatic disease. The role for radiotherapy has not been clearly defined. This article describes three cases of advanced islet cell tumors treated effectively with radiotherapy. This experience, in addition to that from other published reports, suggests that radiotherapy is a useful mode for treating advanced islet cell carcinoma.     

Curative local excision of rectal adenocarcinoma

The records of all 28 patients with rectal adenocarcinoma treated by potentially curative local excision by one surgeon (A.M.C.) between 1970 and 1984 were reviewed. Patient age, sex, tumour size, site, degree of differentiation and level of invasion are reported. The procedure was associated with no mortality and minimal morbidity. Twenty-two patients, followed for an average of 51 months, have either died of other causes or remain free of recurrent or disseminated malignancy. Six patients have required further surgery for local recurrence. Of these, one patient has had a repeat local excision while the remaining five patients have had an abdominoperineal excision of the rectum. All six patients, followed since the second operation for an average of 50 months, are free of further recurrent or disseminated disease. The results reported in this review suggest that in a selected group of patients with rectal adenocarcinoma curative local excision may offer a safe alternative to more radical forms of surgery.     

Therapeutic potential of choline magnesium trisalicylate as an alternative to aspirin for patients with bleeding tendencies

We have compared the effects of acetyl salicylic acid (ASA, aspirin) and choline magnesium trisalicylate (CMT), a non-acetylated salicylate product, on platelet aggregation in human whole blood ex-vivo. Using a whole blood platelet counter, platelet aggregation was quantified by measuring the fall in the number of single platelets at peak aggregation in response to collagen, arachidonic acid (AA), as well as spontaneous aggregation. In double blind and random order, 12 healthy volunteers received, on two separate occasions 10 days apart, a single oral dose of 652 mg ASA or 655 mg CMT. Despite a comparable absorption of salicylic acid from the two drugs, ingestion of ASA resulted in a marked inhibition of platelet aggregation induced by collagen (p less than 0.005), AA (p less than 0.01) and spontaneous aggregation (p less than 0.01), whereas such effects were not observed after CMT ingestion. We suggest that CMT may have therapeutic potential as an alternative to aspirin when inhibition of platelet aggregation can induce bleeding complications.     

Ileoanal reservoir for ulcerative colitis and familial polyposis

Although total proctocolectomy with permanent ileostomy is regarded as the definitive therapy for ulcerative colitis and familial polyposis, psychologic and physical complications with this operation have stimulated the development of the operation of total abdominal colectomy, mucosal proctectomy, ileal reservoir, and ileoanal anastomosis as an alternative surgical procedure. Since 1980, 104 of these operative procedures have been completed with no operative mortality; experience has been gained with both the J- and S-type reservoirs. Despite an appreciable number of postoperative complications, satisfactory function of the reservoir has been achieved in 86 of 91 patients followed up for at least three months after closure of the ileostomy. The remaining five patients have required reinstitution of fecal diversion. Functional results have not differed between two-limbed and three-limbed reservoirs. This operation must be considered a viable alternative in patients with ulcerative colitis and familial polyposis.     

Radiation-induced meningioma. 3 cases

During the same year (1984), we have seen 3 cases of meningiomas following radiation therapy of the brain for previously diagnosed tumors. A causal relationship between irradiation and meningioma has been postulated. Nevertheless, the coincidental occurrence in same patient of two different histological lesions is possible. The neoplasms developed after irradiation are of mesenchymal origin; they are fibrosarcomas, osteogenic sarcomas and meningiomas.     

Use of high-frequency jet ventilation in vertical partial surgery of the larynx

High-frequency jet-ventilation (HFJV) was applied to 30 patients undergoing vertical partial surgery of the larynx for carcinoma of the vocal cords. This technique gave good surgical conditions as it interfered little with the air-ducts. It was carried out with a catheter of only 3 mm external diameter; control of ventilation during surgery was adequate, the average PaO2 being 27.9 +/- 5.6 kPa (209.3 +/- 4.2 mmHg) and the average PaCO2 5.4 +/- 1.4 kPa (40.5 +/- 10.5 mmHg). It avoided also the need for a tracheotomy. In the past, anaesthetic techniques were local anaesthesia combined with neuroleptanalgesia, endotracheal intubation or preoperative tracheotomy. None of these methods being satisfactory, our practice now includes first a nasotracheal intubation with an armoured tube at the beginning of the surgical procedure, followed by HFJV during the removal of the vocal cord, the tracheal tube being slightly pulled out. The tracheal tube is then put back in place before the thyroid cartilage is closed. The contra-indications are the same as those of HFJV. There are two types of complications: complications of HFJV itself, and postoperative complications due to the absence of tracheotomy. No accidents were observed. The only incidents seen were related to the lack of tracheotomy: subcutaneous oedema of the neck during the postoperative period in eight patients and moderate tracheobronchial congestion in five patients.     

Maintaining family planning acceptance levels through development incentives in Northeastern Thailand

The results of a two-year longitudinal study of the effect that development program incentives have upon family planning in Northeastern Thailand are presented. These incentives, implemented by the Population and Community Development Association, Thailand, included animal raising and agricultural, home industry, and environmental activities. An experimental design including baseline and follow-up surveys supplemented by a continuous monitoring system was utilized to test hypotheses on the family planning impacts of the incentives. Findings indicate that the incentives contributed significantly to the maintenance of high levels of family planning practice through the program period 1982-1984.     

Relationship between transmitter release and presynaptic calcium influx when calcium enters through discrete channels.

We have used a three-dimensional diffusion model of calcium entering the presynaptic nerve terminal through discrete channels to simulate experiments relating transmitter release to presynaptic calcium current. The relationship will be less than linear, or will curve downward, if calcium channels are well separated. It will resemble a power-law function with exponent less than the cooperativity of calcium action if channels are clustered closer together. Large presynaptic depolarizations elicit more release than small depolarizations admitting the same calcium influx. This occurs because large pulses open more channels near each other, with the result that the calcium concentration near release sites is greater, due to overlap of calcium diffusing from adjacent channels.