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Biomedical subjects

G Marks

Publications and source records attributed to G Marks.

At least 109 records · Page 6Linked to original sources
PubMed1984

Adjuvant radiation therapy for rectal cancer.

Since 1976, 104 patients with rectal cancer have been treated with a new approach of combined pre- and postoperative radiation. All patients were given 500 rad preoperative irradiation on the day of or the day before surgery. Surgery in the majority of patients was an abdominal perineal resection. The disease was then staged pathologically according to Astler-Coller's modification of Duke's staging. Patients with early stage cancer (Stages A and B1) were followed with no further therapy. Patients with poor prognostic characteristics (Stages B2, C1, C2) were given postoperative pelvic irradiation (4500 rad in 5 weeks). Twenty-nine patients were found to have Stage A or B1 cancer and were followed with no further therapy. Of these 29 patients, 1 patient developed recurrence and one has died of metastatic disease. The excellent survival of patients with early tumors indicates that minimizing the role of adjuvant therapy in this group has not been detrimental to their survival. Fifteen were found to have liver metastases at laparotomy and had just a colostomy and palliative therapy. Sixty patients had Stage B2 and C disease. Thirty-one received postoperative irradiation as per protocol. Twenty-nine patients did not receive postoperative irradiation for a variety of reasons. Follow-up ranges from 1 to 7 years in these patients. Of the 29 patients with Stage B2 and C disease who should have but did not receive postoperative radiation, 10 patients (34%) have developed a recurrence in the pelvis, and 5 other patients (17%) have developed metastatic disease. Of 31 patients who received postoperative irradiation, only 2 patients (6%) developed a local recurrence and 4 patients (13%) have developed distant metastases. Survival at 3 years was 80% for patients receiving the combined treatment, as compared to 42% for those not receiving the postoperative part of the treatment protocol.

Adenocarcinoma↗
PubMed1983

The surgical management of the radiation-injured intestine.

The grim prognosis for patients with severe radiation injury of the intestine need not be considered unalterable. Aggressive, wide-resectional techniques, new nutritional methods, and earlier diagnosis should provide significantly improved results. Reshaping of traditional conservative attitudes, which have been associated with mortality ranging from 20 to 50 per cent, is strongly encouraged. A selectively bolder approach to the intestine injured by radiation is endorsed as a means of reducing the mortality and morbidity and of providing a greater opportunity for preserving or reconstituting acceptable gastrointestinal function.

Female↗
PubMed1983

beta-thromboglobulin and platelet factor 4 levels in retinal vein occlusion.

Fifty-six patients with retinal vein occlusion--35 with central and 21 with branch vein occlusion--were investigated for comparison with an age and sex matched control group. Mean levels of beta-thromboglobulin and platelet factor 4 were significantly higher (p less than 0.001) in both the group with central and the group with branch retinal vein occlusion than in the control group. A significant increase of beta-thromboglobulin (p less than 0.001) was also found in the retinal vein occlusion group in those patients who were not hyperlipidaemic or diabetic (n = 39). Weak correlations were found between levels of lipoprotein cholesterol and plasma beta-thromboglobulin. Increased platelet aggregation may contribute to the aetiology of retinal vein occlusion.

Beta-Globulins↗
PubMed1983

Platelet activation during steady state sickle cell disease.

Previous reports have given conflicting conclusions of the role platelets may play in initiating vaso-occlusive sickle cell crisis. Seven patients homozygous for sickle cell hemoglobin, and seven age, race and sex matched controls were each studied on at least two occasions in a six week period of normal health. The number of platelets circulating as aggregates, the plasma concentration of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF-4) were significantly elevated compared with controls. These findings were confirmed with a second series of fourteen patients and nine controls. Patient's platelets in plasma adjusted for both platelet number and citrate concentration aggregated more in response to low concentrations (0.4 and 1 microM) but less to higher concentrations (4 and 20 microM) of ADP and needed significantly more prostacyclin (PGI2) to inhibit ADP induced aggregation than did platelets from control subjects. There was no significant difference in plasma concentration of fibrinopeptide A and thromboxane (Tx)B2, nor in the platelet generation of TxB2 and release of serotonin and beta TG induced by aggregating agents. Thus, the platelets of patients with sickle cell anemia in the steady state are readily activated and respond in vivo by increased formation of aggregates and release of beta TG and PF-4.

Adenosine Diphosphate↗
PubMed1982

Guidelines for use of the flexible fiberoptic sigmoidoscope in the management of the surgical patient.

Based on data from many clinical studies and programs, guidelines are presented for application of the flexible fiberoptic sigmoidoscope in the management of the surgical patient. The flexible fiberoptic sigmoidoscope has proved to be an instrument of extraordinary capability in detecting colorectal neoplasms with yields being two or three times greater than those of the rigid sigmoidoscope in the symptom-resolution, polyp and cancer surveillance patient categories. In addition, the practical advantages of the narrow diameter, flexibility, and length of the fiberoptic sigmoidoscope are readily appreciated when the surgeon finds that he can satisfactorily examine patients with rectal or sigmoid strictures, marked angulations, or contracted lumens in whom a rigid scope would be unsuitable. Data from the authors' comparative study of more than 3000 patients have permitted the development of not only guidelines for the application of the flexible fiberoptic sigmoidoscope but an appreciation of the modified role of the rigid sigmoidoscope and the proper relationship between the flexible fiberoptic sigmoidoscope and the flexible fiberoptic colonoscope. A most important consideration is based on data regarding the site distribution of 400 benign premalignant neoplasms detected in the comparative study. The even distribution of these lesions throughout the terminal 50 cm of colorectum underscores the need to examine as much of the colorectum as possible.

Colonic Diseases↗
PubMed1982

Combined pre and postoperative radiation for carcinoma of the rectum.

Since 1976, a new approach to adjuvant radiation therapy in carcinoma of the rectum has been used at Thomas Jefferson University Hospital. Seventy-eight patients with biopsy-proven invasive carcinoma of the rectum have been treated with low dose preoperative radiation, 500 rad given either on the day of or the day before surgery. Following surgery, the lesions were pathologically staged according to Astler-Coller's Modification of Duke's staging. Patients with good prognostic features (Stage A or B1) were followed with no further treatment while patients with poor prognostic characteristics (Stage B2, C1 and C2) were treated with aggressive postoperative pelvic radiation, 4500 rad delivered in five weeks. All patients entered into this study received the preoperative dose of 500 rad. Fifty-six patients underwent an A-P resection, four patients underwent a low anterior resection and ten patients had a combined abdominal transsacral resection. Eight patients were found to have liver metastasis at laparotomy and underwent a colostomy followed by palliative therapy. Twenty-nine patients were found to have early disease, Stage A or B1, and were given no further therapy. Of 41 patients with Stage B2 or C, 25 patients received the full course of postoperative radiation. Sixteen patients did not receive postoperative radiation for a variety of reasons. Follow-up in these patients ranges from six months to a maximum of 48 months with a median follow-up of 18 months. Sixty-nine of the total group of 78 patients are currently alive. Two patients with early tumor (Stage A or B1) have died of metastasis. One other patient with Stage A carcinoma died of unrelated causes. Two of the 25 patients receiving postoperative radiation developed metastatic disease, but none of the patients developed local recurrence in the pelvis. Six of 16 patients who should have received postoperative radiation, but did not recurred. Four of these six recurrences have been in the pelvis. Both the incidence of failure and the pattern of recurrence between these two groups of patients who did not receive postoperative radiation is suggestive of a better effect in the PR unrelated group. Survival of patients treated with this approach appears to be improved.

Follow-Up Studies↗
PubMed1982

[Modern x-ray apparatus for pediatric radiology (Pädiatrix) (author's transl)].

First experiences with the new apparatus "Pädiatrix" in pediatric radiology are reported. The apparatus is especially constructed for babies and children. X-ray pictures can be taken close-up and in distance with the tube above the table. Fluoroscopy can be performed with image intensivier. X-ray pictures with Bucky-diaphragm by the technique of middle and normal size and oblique or horizontal direction are to be made. Tomography and zonography can be done. The apparatus has proven useful for clinical radiological diagnostics after three years of experience.

Child↗
PubMed1979

Adenomatous and carcinomatous changes within hyperplastic colonic epithelium.

Hyperplastic colonic polyps are benign, nonneoplastic proliferations; unlike tubular and villous adenomas, they do not predispose the patient to colonic cancer. Theoretically, these hyperplastic polyps, like normal colonic epithelium, should be able to undergo adenomatous transformation and possibly develop into cancer. In this report, we discuss an unusual case of a patient with numerous hyperplastic polyps, in which adenomatous changes occurred and cancer developed. We also discuss the significance of these changes as they relate to the polyp-cancer sequence.

Adenoma↗
PubMed1979

Sigmoidoscopic examinations with rigid and flexible fiberoptic sigmoidoscopes in the surgeon's office: a comparative prospective study of effectiveness in 1,012 cases.

The results obtained from 1,012 examinations in an on-going, cooperative study indicate that the overall yield provided by use of the flexible fiberoptic sigmoidoscope is 3.2 times greater than that of examinations with the rigid sigmoidoscope. More than twice (2.4 times) the number of polyps and more than three times the number of cancers were detected with the flexible fiberoptic sigmoidoscope. Experienced endoscopists can perform an examination with the flexible fiberoptic sigmoidoscope expeditiously in the office with minimal patient preparation, a high level of patient and physician acceptance, and relative safety when the usual mandatory colonoscopic precautions and guidelines are obeyed. The extraordinary advantages demonstrated by this study warrant wide clinical application of the flexible fiberoptic sigmoidoscope. We strongly recommend provision be made for appropriate training of physicians in the use of the instrument.

Colon, Sigmoid↗
PubMed1976

Combined abdominotranssacral reconstruction of the radiation-injured rectum.

Reconstruction of the rectum by a technic of combined abdominotranssacral proctocolectomy and proctocolostomy is presented as an alternative to the surgical conservatism that has been the time-honored approach to the management of radiation-injured rectum. The procedure has permitted safe accomplishment of rectal anastomosis with as little as a 1 cm distal rectal stump. Satisfactory, true anal sphincteric continence is enjoyed by six patients who have been completely reconstituted, and satisfactory reconstitution in the remaining two is anticipated. These results suggest that reinspection of the traditional approach to the radiation-injured rectum is warranted now that safe and physiologically effective reconstitution can be accomplished by a combined abdominotranssacral technic.

Abdomen↗
PubMed1976

Attention, practice, and semantic targets.

Observers detected letters in streams of digits under conditions of divided or selective attention for a period of 10 hr. There were marked practice effects both on the detectability of targets and on the response criteria used by observers. The detectability of targets and the response criteria were both strongly dependent on events in the contralateral channel. The same effects were observed in a second experiment in which the task was to detect animal names in streams of nouns. The data are similar to those obtained in recent experiments using pure tones, so that a unified theory of attention should be possible, valid alike for semantic and nonsemantic messages. Such a theory is outline.

Attention↗
PubMed1975

Pneumoperitoneum, pneumomediastinum and pneumopericardium following dental extraction.

Pneumoperitoneum, pneumomediastinum, pneumopericardium and subcutaneous emphysema developed in a patient following simple dental extraction. Other causes of this unusual complication, such as pneumatosis cystoides intestinalis, insufflation of fallopian tubes, pulmonary-peritoneal fistula, post-partum knee-chest exercises, laparotomy, paracentesis and peritoneal dialysis should be considered when peritoneal signs are absent so that unnecessary laparotomy can be avoided.

Adipose Tissue↗