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Biomedical subjects

S M Jackson

Publications and source records attributed to S M Jackson.

At least 73 records · Page 4Linked to original sources

Structure-function analysis of the rat prolactin promoter: phasing requirements of proximal cell-specific elements.

Expression of PRL, a member of the GH family of genes, is restricted to the lactotroph cells of the anterior pituitary. The proximal promoter of the rat PRL (rPRL) gene contains four factor-binding sites. Three nonadjacent elements, footprints (FP) I, III, and IV, are separated by an integral number of helical turns and bind a pituitary-specific factor, LSF-1. FP II binds another factor present in pituitary and nonpituitary cells. The mechanisms by which DNA-bound proteins influence RNA polymerase-II activity over large distances are not fully understood, but protein-protein interactions, with looping of intervening DNA, may bring distant sites into close proximity. Here, we demonstrate, using protein titration studies, that LSF-1 binds to the most proximal FP I element with the highest affinity, whereas it binds the more distal elements, FP III and FP IV, with progressively lower affinities. Time-course and salt-sensitivity studies reveal that binding of LSF-1 to all three pituitary-specific rPRL promoter sites occurs rapidly (less than or equal to 1 min) and requires fairly high salt concentrations (greater than or equal to 300 mM KCl) to destabilize protein-DNA interactions. Moreover, once bound, the pituitary nuclear factor(s) induces a conformational change in rPRL DNA structure with greatly delayed kinetics (greater than 15 min) and at a different salt concentration than are required for simply factor binding. Taken together, these data suggest a model in which LSF-1 initially binds fairly rapidly to multiple nonadjacent elements and then interacts with itself or other DNA-bound proteins much more slowly, possibly looping or bending the rPRL promoter.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Impact of new radiotherapy modalities on the surgical management of cancer of the esophagus and cardia.

At the Cancer Control Agency of British Columbia, 483 patients with cancer of the esophagus and cardia were seen from 1970-1980. Four hundred and one out of 483 (83%) had tumors larger than 5 cm (T2) and in 288/483 (60%) the disease had extended beyond the esophageal wall (T3). The overall 5-year survival rate was only 9% for all patients treated by external irradiation. The 5-year survival for a selected group having esophagectomy was 20%. Most patients died of persistent cancer at the primary site (83%); the cause of death was aspiration pneumonia (82%) due to obstruction caused by the persistent cancer. Our most recent experience using intracavitary irradiation either prior to or after external irradiation in 211 patients has been safe and simple and preliminary analysis of treatment results suggests that it has improved the therapeutic ratio. The analysis of quality of life at 6 months following therapy as it relates to performance status, swallowing ability, weight, and pain indicated significant improvement in all of these parameters. Of 171 patients, 33% were still alive at 1 year, 26% at 2 years, and 19% at 3 years following treatment. Of 43 patients suitable for preoperative irradiation, only 26 patients were actually resected and 19 of them are still alive with no evidence of disease, 8 to 30 months. The rationale and technical aspects of the combined treatment are described in detail. Treatment results, complications and an outline for future programs based on this experience are also described.

Body Weight↗

Clinical results in carcinoma of the cervix: radium compared to caesium using remote afterloading.

In 1979 the Cancer Control Agency of British Columbia changed from radium to remote controlled afterloaded caesium in the treatment of carcinoma of the cervix. In the 3 years prior to the change, 139 patients received radium as part of their treatment and in the 3 years after the change, 158 patients received caesium. Overall referral patterns, patient and cancer demographics, and treatment policies were stable throughout the 6-year period. Radiotherapy technique, dose, dose distribution and dose rate were comparable for both radium and caesium treated patients. The results of treatment in the two time periods showed no difference in survival, local tumour control or complications. The use of afterloading has not compromised treatment results and has allowed better nursing care for patients and protection from radiation for all staff.

Brachytherapy↗

Superfractionated radiotherapy in grade III, IV intracranial gliomas.

Preliminary results of superfractionation in the treatment of glioblastoma led to a randomized trial consisting of 76 patients. All patients received whole brain irradiation followed by a 1000 cGy boost to the primary site. Thirty-four patients received standard daily treatment to 4000 cGy, whereas 42 patients received superfractionated radiation, treating three times a day to a total dose of 4760 cGy. No significant difference was found between the 5-year survival of the superfractionated group and the standard treatment group. Early reactions were greater for superfractionation whereas late effects were less.

Adult↗

Reduction mammaplasty using the inferior glandular "pyramid" pedicle: experiences with 300 patients.

A comprehensive review of 300 patients undergoing reduction mammaplasty (576 breasts) based on an inferior glandular pedicle is presented. The average age was 31.7 years, weight 146.6 lbs., and the amount of tissue removed 1313.6 gm. No deepithelialization of the skin was performed, and average operating time was 174 minutes. The average distance the nipple-areola complex was moved was 12 cm, with the longest being 22.5 cm. Fifty-seven percent had fibrocystic mastopathy on histologic analysis, and no malignancies were found, even in patients who had undergone a previous mastectomy for breast carcinoma. The most common complication (3.1 percent) was minor suture line necrosis along the infra-mammary crease. All healed without intervention. There was no necrosis or sensory loss to the nipple-areola complex in any patient, and cosmesis was excellent. The analysis also showed that the use of epinephrine, injected subcutaneously just prior to the operation, significantly decreased intraoperative blood loss (p less than 0.0005), regardless of the amount of tissue removed, and eliminated the need for transfusions.

Adult↗

Primary seminoma of the mediastinum. Cancer Control Agency of British Columbia experience.

Six patients with primary seminoma of the mediastinum were treated at the Cancer Control Agency of British Columbia during the period from 1970 to 1982. Primary treatment used was external beam radiotherapy. Only one patient received both radiotherapy and chemotherapy. Tumor dose ranged from 3000 cGy in 16 daily fractions in 3 weeks to 3500 cGy in 20 daily fractions in 4 weeks using parallel opposed fields on megavoltage machines. Two patients received additional small-volume boost to the superior mediastinum, delivering 500 cGy and 1000 cGy, respectively. All patients had complete resolution of the mediastinal mass after treatment and are alive and free of disease. One patient developed a metastasis to the fifth lumbar vertebra 1 year after treatment. This metastatic lesion was treated with radiotherapy and the patient is alive and free of clinical disease. Mediastinal seminoma is radiosensitive and radiocurable.

Adult↗

Lymph node metastases from well-differentiated thyroid cancer. A clinical review.

The records of 77 patients with well-differentiated thyroid cancer and proved lymph node metastases have been reviewed. The control of regional metastases was satisfactory in those with only a few nodes involved when limited dissections were utilized initially. In those patients with more extensive nodal involvement, the ultimate rate of failure to control disease in the neck was unacceptably high among those who initially underwent conservative localized neck dissection. Although regional control will not influence mortality, a more aggressive modified neck dissection is recommended for patients presenting with significant nodal involvement.

Adenocarcinoma↗

Alcohol, smoking, social and occupational factors in the aetiology of cancer of the oral cavity, pharynx and larynx.

A case-control study of 374 patients with primary epithelial cancers of the oral cavity, oro- and hypopharynx, and larynx is reported, the controls being patients with selected other cancers, matched for age and sex. Of all eligible patients, 93% were interviewed. Increased risks were seen with alcohol consumption and, less strongly, with smoking, which for all sites could be adequately fitted by either a multiplicative or an additive model. However, the site-specific relationships were different, alcohol consumption being significantly associated only with oral cavity, pharyngeal and extrinsic laryngeal tumours, and smoking only with intrinsic laryngeal tumours. Increased risks were associated with low socio-economic status, the unmarried state, and poor dental care. No significant associations were seen with specific occupational exposures.

Alcohol Drinking↗

Paranasal sinus malignancy--a retrospective analysis of treatment methods.

A retrospective analysis has been made of all cancers of paranasal sinuses seen at the Cancer Control Agency in Vancouver during the years 1970 to 1978. The overall crude five year survival for all cases (49) was 46%. A combined treatment using irradiation and surgery in selected cases generated a five year survival rate of 74.4% as compared to 42.1% in cases receiving irradiation alone. The clinical presentation, staging, and the need for the individualization of treatment methods based on a realistic knowledge of the pathological extent of the disease are discussed.

Adenocarcinoma↗

Pions, Vancouver.

Clinical treatments at TRIUMF started in November, 1979. Ten patients with malignant subcutaneous nodules had 14 lesions treated with pions and 37 other nodules treated with 280 kV X rays. Three different fractionation regimens were used with X ray doses spanning the expected RBE range of pions. The RBE for pions for acute skin reaction for 10 fractions had a mean value about 1.5, while for 3 fractions it was 1.3 maximum. No dissociation of acute and late skin effects was seen with follow-up to 27 months after treatment. Phase 1-2 studies of Pion-Boost Therapy for patients with glioblastoma multiforme will begin in May, 1982. These will be followed in August with treatments of advanced pelvic malignancies using pions only. The existing beam line at TRIUMF will be upgraded and commitments have been given to go to higher beam currents. As a result, the dose rate should increase by a factor of at least two, allowing treatment of clinically relevant volumes in acceptable times by 1983-1984.

Brain Neoplasms↗

Senile cataracts and myopia.

A retrospective survey of 32 persons with myopia and 38 persons with emmetropia who had been operated on at two US Army hospitals on the California coast showed that the persons with myopia who had worn eyeglasses for at least 20 years underwent cataract extraction at a significantly (P less than .00005) older age than the persons with emmetropia (median age at the time of the operation was 70 years, compared with 64 years). These results support the theory that some protection against solar ultraviolet radiation is offered the eyes by eye wear worn continuously and that solar ultraviolet radiation may be a contributing factor in the formation of human senile cataracts.

Adult↗

Radiation therapy for seminoma of the testis: results in British Columbia.

Between 1942 and 1978 radiation therapy was given to 362 patients with seminoma of the testis, 40 (11%) of whom had a history of maldescent of either testis. The disease was classified retrospectively according to the extent of the primary tumor, the involvement of the regional lymph nodes and the presence of distant metastases (the TNM system), and the results of treatment were analysed according to the classifications. Among the 275 patients referred for treatment at least 5 years before this analysis the 5-year survival rates were 87% overall, 96% for those with a T1 or T2 (relatively localized) tumour but no evidence of nodal involvement or distant metastases and 62% for the 24 with palpable or distant metastases at the time of clinical presentation. Of the 28 patients in whom the disease recurred 15 were successfully treated. A second primary testicular tumour developed in the contralateral testis of eight patients. The incidence of other cancers was not increased over the expected rate in the general male population of the same age.

Adult↗

Malignant lymphoma of the testis: review of 17 cases in British Columbia with survival related to pathological subclassification.

We reviewed 17 patients in whom malignant lymphoma appeared to arise primarily in the testis without evidence of widespread dissemination. Malignant lymphoma of the testis occurring as part of a generalized disorder was not included. That the disease may be localized to the testis and can be cured (or long-term survival without evidence of dissemination) are supported by the results reported. The clinical features were reviewed and compared to those recorded in the literature. The 16 tumors in adults were all classified as diffuse histiocytic lymphoma. They were further classified as large cleaved cell, large non-cleaved cell and large non-cleaved cell (? immunoblastic) lymphoma. Survival was correlated with this classification and none of the patients with large cleaved cell tumors has died of malignancy. Prognosis also was related to clinical presentation and initial treatment. All surviving patients underwent orchiectomy and wide-field radiotherapy.

Aged↗

Make costly physicians accountable.

Physicians make the majority of decisions about the type and quantity of medical care, but cost-sharing mechanisms intended to control costs place the burden upon the patient. This article proposes a variety of mechanisms for placing this burden upon the small group of physicians identified as being excessively costly.

Cost Control↗

Whole body electron therapy in mycosis fungoides--a successful translational technique achieved by modification of an established linear accelerator.

A translational technique, adapting an established MEL SL75/10 linear accelerator, which gives a satisfactory physical and clinical 3 MeV whole-body electron treatment in mycosis fungoides is described. Tolerance of the patients proved excellent and 16 out of 21 achieved satisfactory remission of the disease. In spite of delivering significant skin doses it was possible to re-treat two relapsing patients without complications and with clinical success.

Adult↗