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Biomedical subjects

J T Mason

Publications and source records attributed to J T Mason.

At least 37 records · Page 2Linked to original sources
PubMed1986

Adjuvant radiotherapy following radical prostatectomy: results and complications.

Between 1954 and 1978, 148 patients underwent radical perineal prostatectomy for adenocarcinoma clinically confined to the prostate gland. This report is based on 45 of these patients with microscopic extension of disease beyond the gland and a minimum 5-year followup. Of the patients 22 received adjuvant external beam radiation therapy and 23 did not. The groups were comparable with regard to significant prognostic variables. Patient selection was by surgeon preference. Local recurrences were seen in 1 of 22 patients (5 per cent) receiving adjuvant radiotherapy and 7 of 23 (30 per cent) undergoing an operation alone (p less than 0.05). Of 8 patients with local recurrence 7 died of the disease. Delayed radiotherapy of a local recurrence generally was not effective in controlling the disease. Of the 11 patients who died of prostatic cancer with a mean followup of 9.2 years 3 received adjuvant radiotherapy and 8 did not. Severe but nonfatal long-term complications were seen in 14 per cent of the irradiated patients and 6 per cent of those treated with an operation alone. Most of the complications occurred in the earlier years of the study in patients who received 60cobalt radiotherapy. When clinical stage B cancer of the prostate is found to be pathological stage C following radical perineal prostatectomy, adjuvant radiotherapy can decrease the incidence of subsequent local recurrence. The potential risk of adjuvant radiation therapy should be weighed and its use considered, particularly in patients whose tumor extends to the surgical margins or who have seminal vesicle invasion.

Adenocarcinoma↗
PubMed1985

Amiodarone-associated epididymitis: drug-related epididymitis in the absence of infection.

An atypical epididymitis syndrome developed in 6 of 56 men (11 per cent) treated with amiodarone, an effective new anti-arrhythmic agent. Of the 6 patients 5 (87 per cent) had bilateral epididymal enlargement and pain. The mean dosage in the patients with epididymitis was 700 mg. per day compared to 377 mg. per day in all patients (p less than 0.01). No infectious etiology was implicated in any patient. Temporary discontinuation or decrease in dosage is recommended for patients who suffer noninfectious epididymitis while on amiodarone therapy.

Adult↗
PubMed1985

The inadvertent CT demonstration of intussusception.

We report a patient with idiopathic ceco-colic intussusception diagnosed by computed tomography (CT). Due to an unusual set of circumstances, the accepted algorithm of diagnostic investigations was not followed. This led to the inadvertent CT demonstration of an intussusception in an adult as a thick-walled mass containing a multiplicity of barium and gas-filled loops.

Adult↗
PubMed1984

Acyl chain interdigitation in saturated mixed-chain phosphatidylcholine bilayer dispersions.

The molecular packing of various fully hydrated mixed-chain phosphatidylcholines was studied by X-ray diffraction and electron microscopy. All of the mixed-chain phosphatidylcholines under study were shown to adopt a lamellar or bilayer form in aqueous media. The bilayer thickness of these mixed-chain phosphatidylcholines was determined from the lamellar repeat distance in the small-anglé X-ray diffraction region by controlled swelling experiments. At T greater than Tm, the bilayer thickness of C(18):C(12)PC and C(18):C-(10)PC is found to be comparable to that of C(14):C(14)PC. In contrast, the bilayer thickness of these highly asymmetric phosphatidylcholines is considerably less than that of the symmetric C(14):C(14)PC at temperatures below Tm. Moreover, the wide-angle X-ray diffraction patterns taken at T less than Tm consist of at least two sharp reflections at 4.2 and 4.6 A. These X-ray diffraction data suggest that these highly asymmetric mixed-chain phospholipids, in excess water, form mixed interdigitated bilayers in the gel state and that the acyl chain packing in the gel-state bilayer is not hexagonal. The freeze-fracture planes of these mixed-chain phosphatidylcholines are discontinuous at T less than Tm, supporting the conclusion drawn from X-ray diffraction data that these highly asymmetric phosphatidylcholines form interdigitated bilayers at temperatures below Tm. The molecular packing of fully hydrated C(18):C(14)PCs in bilayers is distinctively different from that of C(18):C(10)PCs or C(18):C(10)PCs.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemical Phenomena↗
PubMed1984

Urological trauma in the Pacific Northwest: etiology, distribution, management and outcome.

A computer-assisted review identified 184 patients with genitourinary tract injuries among 5,400 hospitalized for trauma. Particular attention was directed to the controversial groups of patients with blunt renal and posterior urethral injuries. Management of renal injuries was based on clinical criteria. Subsequent renal exploration was necessary in only 1 of 115 patients with renal contusions, or simple or deep lacerations who underwent initial expectant management. Followup was available in all patients with severe renal injuries and in 53 per cent with renal contusions or simple lacerations. Parenchymal loss was noted on an excretory urogram in only 1 patient and none suffered hypertension, hydronephrosis or other sequelae. A staged approach was preferable to immediate repair of posterior urethral injuries. Seven patients managed by initial cystostomy drainage followed by secondary urethral repairs did well. Primary realignment was complicated by stricture, incontinence or impotence in 3 of 6 patients.

Accidents, Occupational↗
PubMed1984

Use of nerve stimulator for simple and accurate obturator nerve block before transurethral resection.

Adductor contraction from obturator nerve stimulation occurs frequently in certain situations during transurethral operations. Bladder perforation is a common result. A simple and safe technique involving use of a nerve stimulator for accurate obturator blockade is described. There have been no adductor contractions in more than 275 transurethral resections during a 2-year interval. There were no complications from the block itself or use of the nerve stimulator.

Electric Stimulation↗
PubMed1984

Total prostatectomy for localized prostatic cancer.

Several treatment options currently are available for the patient with clinically localized carcinoma of the prostate and each has its proponents. Comparison of results between institutions becomes necessary to determine the relative value of these treatments, keeping in mind the absence of a suitable control group in any series. Such inter-institutional treatment comparisons are possible only if the patient compositions are similar in terms of age, grade and extent of disease. Comparisons of patients with stage B disease frequently are made because most urologists agree that these patients have palpable disease confined to the prostate and no evidence of metastasis. At our clinic willing patients with clinically localized adenocarcinoma of the prostate who have an expected 15-year survival are treated preferentially with total prostatectomy. We summarize our experience with total prostatectomy in 215 consecutive patients, including 213 who were available for followup. There were 16 patients with clinical stage A, 195 with clinical stage B and 2 with clinical stage C disease. Of these patients 207 underwent radical perineal prostatectomy and there were no operative deaths. Patients did not receive adjuvant hormonal therapy unless disease recurred. Of the 110 patients who have undergone the operation within the last 5 years 98 per cent are alive. Actual survival and survival free of disease, respectively, for the entire series were 55 and 48 per cent at 15 years, 75 and 67 per cent at 10 years, and 94 and 86 per cent at 5 years, compared to 55 and 48, 74 and 67, and 95 and 90 per cent, respectively, for the 195 patients with clinical stage B disease. We believe these results demonstrate that in terms of local control of the disease, over-all survival and survival free of disease total prostatectomy remains the optimal treatment for patients with clinically localized carcinoma of the prostate.

Adenocarcinoma↗
PubMed1983

Effect of liposomal size on the calorimetric behavior of mixed-chain phosphatidylcholine bilayer dispersions.

The effect of liposomal size on the endothermic transition profiles of the saturated mixed-chain phosphatidylcholines 1-stearoyl-2-myristoyl-sn-glycero-3-phosphocholine and 1-stearoyl-2-caproyl-sn-glycero-3-phosphocholine has been investigated. Liposomal bilayer dispersions of progressively smaller average diameter were prepared by extrusion of coarse multilamellar preparations of these lipids through polycarbonate membrane filters of decreasing pore size from 3-to 0.2-micrometers diameter. These samples were then investigated by high-sensitivity differential scanning calorimetry and negative-strain electron microscopy. It was found that coarse dispersions of the above lipids are composed of liposomes whose average diameter is considerably smaller than that typically associated with multilamellar liposomes of synthetic phosphatidylcholines. This fact, coupled with an analysis of the size dependence of the transition cooperativity, leads to the conclusion that the small size of the liposomes limits the transition cooperativity in coarse dispersions of these mixed-chain phosphatidylcholines. Thus, the broad and highly asymmetric transition profiles that have been observed in previous studies of these phosphatidylcholines are postulated to arise largely from this size dependence, rather than from characteristic packing properties of the phospholipid acyl chains as has been previously suggested.

Calorimetry, Differential Scanning↗
PubMed1981

Calorimetric investigations of saturated mixed-chain phosphatidylcholine bilayer dispersions.

A series of saturated mixed-chain phosphatidylcholines were prepared whose sn-2 acyl chains are two, four, six, and eight carbon atoms shorter than the sn-1 acyl chain. The calorimetric behavior of multilamellar bilayers of these phosphatidylcholines in excess water is investigated. The phosphatidylcholines display cooperative phase transitions which are dependent upon both the difference in chain length and the position of the acyl chains on the glycerol backbone of the phospholipid. A model is proposed which suggests that the thermotropic behavior of the mixed-chain phosphatidylcholines results from progressively greater interdigitation of the acyl chains of the phospholipid across the bilayer center, in the gel state, as the chain-length difference is increased beyond a minimum value. The disruptive effect of the terminal methyl groups of the fatty acyl chains upon the bilayer packing stability is also stressed. Dispersions of some of the mixed-chain phosphatidylcholines display transition endotherms which appear to be composites of two or more individual transition peaks. The dependence of this behavior on the thermal history of the dispersions is investigated. It is proposed that these peaks arise from the ability of the phosphatidylcholines' acyl chains to pack in more than one interdigitated conformation in the gel state.

Calorimetry, Differential Scanning↗
PubMed1980

Primary adenocarcinoma of bladder.

Since 1959, 10 patients with primary adenocarcinoma of the bladder were treated at the Virginia Mason Medical Center for an incidence of 1.5 per cent of all bladder cancers. This retrospective study shows that histologic grade and tumor location had a variable influence on survival whereas clinical stage appeared to have a direct effect on survival. The only long-term survivors were the 4 low-stage patients who underwent radical cystectomy.

Adenocarcinoma↗
PubMed1979

Carcinoma of the prostate: local control with external beam radiation therapy.

Local clinical control of the primary disease was evaluated in 209 patients with stage C adenocarcinoma of the prostate treated with definitive external beam radiation therapy and followed for a minimum of 2 years. Of these patients 92 per cent required no further prostatic operations for obstruction. Prostatectomy before therapy did not necessarily prevent later prostatic obstruction from occurring. Of 129 patients who had only a needle biopsy before irradiation 90 per cent had improvement of the obstructive and/or irritative symptoms as tumor regression occurred with therapy and these patients did not require a later prostatic operation for obstruction. Stricture formation occurred in 8 per cent of the patients and was not influenced by the type of preirradiation prostatic operation done. If transurethral resection was reuqired after irradiation it was technically more difficult but the morbidity was acceptable. The incidence of hematuria and incontinence was far less than that reported in non-irradiated patients with this disease. Most tumors exhibited a down-grading effect after irradiation. There were no deaths attributable to the treatment. Over-all, 83 per cent of the 209 patients had no urinary complaints after completion of therapy. From a urological viewpoint, good clinical local control is achieved in the patient with stage C adenocarcinoma of the prostate treated with external beam radiation therapy.

Adenocarcinoma↗