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Biomedical subjects

J R Jacobs

Publications and source records attributed to J R Jacobs.

At least 127 records · Page 7Linked to original sources
PubMed1986

Prognostic significance of tumor growth during radiation therapy.

A retrospective review of 282 consecutive patients with squamous cell carcinoma of the head and neck that were seen in the Radiation Oncology Department from January 1, 1980, through December 31, 1983, was performed. From this population a subgroup of six patients was identified that experienced growth of tumor in the radiation field during treatment. All except one of these patients expired from progression of cancer within 16 months. At the time of writing, the one remaining patient has progressive cancer in spite of additional therapy. Growth of cancer in the radiation field during therapy is unusual. It appears to be associated with a very poor prognosis even with aggressive salvage therapy. This observation should be taken into consideration in the medical/surgical management of these patients.

Carcinoma, Squamous Cell↗
PubMed1985

Staging parameters for cancers of the head and neck: a multi-factorial analysis.

Utilizing a multi-variate computer based analysis technique, the 1,400 case head and neck tumor registry of Washington University was examined for possible staging variables as an alternative to the current TNM system. Site, age, characteristics of surgical margins, and absence of neck node metastasis were identified as being predictive of nonrecurrence of cancer. A computer model utilizing the variables was compared to the current TNM system and found to be somewhat better (71.2% vs. 65.2%) in accuracy of prediction of nonrecurrence of cancer. Further analysis suggests that future improvements in predictive ability of the model will have to await the identification of new variables such as those that might arise from the current work in areas of flow cytometry or human stem cell cultures.

Computers↗
PubMed1984

Correlation between response to cisplatinum-combination chemotherapy and subsequent radiotherapy in previously untreated patients with advanced squamous cell cancers of the head and neck.

Induction chemotherapy, followed by surgery and/or radiotherapy was utilized in patients with advanced squamous cell carcinoma of the head and neck. During these trials, the authors observed that response to chemotherapy predicts further response to subsequent radiotherapy. This study was comprised of 57 patients with 60 separate neoplasms who demonstrated less than complete response (partial or no response) to initial treatment with a combination chemotherapy containing cisplatin. Subsequently radiotherapy, either 5000 rad preoperatively or 6600 rad as definitive therapy, was employed. Forty-one of the 42 tumors with initial partial response to chemotherapy also responded to radiotherapy (97.6%). Only one of the 18 tumors that initially failed to respond to chemotherapy subsequently responded to radiotherapy (5.5%). This observation suggests that patients with head and neck cancer sensitive to initial chemotherapy share parameters that are also radiation sensitive.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1984

Intracellular control of axial shape in non-uniform neurites: a serial electron microscopic analysis of organelles and microtubules in AI and AII retinal amacrine neurites.

AI and AII cat retinal amacrine cells have highly varicose non-uniform, neuritic processes. Processes of both types were reconstructed via a computer system using serial electron micrographs. These reconstructions were analyzed for (a) varicosity volume, surface area, and length, (b) "neck" volume, surface area, and length, (c) number of microtubules within the varicosity, (d) number of microtubules within the "neck," and (e) volume and surface area of mitochondria and smooth endoplasmic reticulum and large smooth vesicular bodies within the processes. Correlation of these parameters revealed a linear relationship between the number of microtubules in the necks and mean neck cross-sectional area (rs = 0.780, P less than 0.001), while microtubule number within the varicosities showed no correlation with varicosity volume (rs = 0.239, P greater than 0.2). Varicosity volume did, however, correlate strongly with the summed volume of mitochondria and smooth vesicular bodies contained within the varicosity for both cell types examined. The ratio between membranous organelle volume and varicosity volume for AI amacrine processes of 1:6.97 (rs = 0.927), differed from the ratio of 1:1.80 for the AII amacrine processes (rs = 0.987). Similar relationships were observed in other nonvaricose neurites such as optic tract axons. Membranous organelles appear to contribute an additional obligatory volume to the cytosol that can be as much as seven times the organelles' direct volume. These observations suggest that both the cytoskeletal components, and the membrane organelles play a direct role in determining neurite shape.

Animals↗
PubMed1984

Hazards encountered in management of basal cell carcinomas of the midface.

Basal cell carcinomas often exhibit aggressive and destructive behavior on the midface, with invasion into the orbit, paranasal sinuses, and even the frontal fossa. Minor modifications in surgical procedures for cosmetic considerations may have devastating consequences on the patient's survival. Tumor extirpation should not be compromised by preoperative planning of the method of reconstruction to be used. Margin control intraoperatively with either conventional frozen sections or the fresh tissue Mohs technique is mandatory for success. If any margin is questionable, reconstruction should be delayed at least until permanent sections confirm complete tumor removal. Ten cases are presented and the literature reviewed to emphasize that inadequate initial management probably contributes more to the observed destructiveness of these lesions than histologic aggressiveness or embryologic patterns of the midface.

Aged↗
PubMed1981

Posterior packs and the nasopulmonary reflex.

Increased mortality and arterial hypoxemia have long been associated with posterior nasal packs placed for control of severe epistaxis. Several authors have postulated a nasopulmonary reflex to partially explain this clinically observed phenomenon. In ten young, healthy subjects, using a multiparameter pulmonary evaluation, posterior nasal packs were placed and no significant changes were observed in lung volumes, flow and alveolar gas exchange, especially oxygenation. These findings suggest that aspiration, sedation, and degeneration of pulmonary function with age, not a nasopulmonary reflex, have not been adequately emphasized in previously performed studies.

Adult↗
PubMed1979

Head and neck manifestations of SLE.

The records of 100 consecutive patients hospitalized with systemic lupus erythematosus were reviewed, and a 76 percent incidence of head and neck signs and symptoms was found. The findings of this study correlate with previous reports. Although no head and neck manifestations or combination of them is pathognomonic of the disease, the family physician should consider the diagnosis of systemic lupus erythematosus in young adults who present with otherwise unexplained and nonspecific head and neck findings.

Adult↗
PubMed1978

Posterior tracheal laceration: A rare complication of tracheostomy.

Tracheostomy is an operation with a long history and many potential complications. Two case reports of acute posterior tracheal wall laceration, a rare complication, are presented. Althoug previously described as being secondary to inadvertent knife contact with the posterior tracheal wall, both of these cases are thought to be due to insertion of the tube with excessive force against tissue made friable by previous radiation. The diagnosis should be suspected if poor ventilation follows insertion of an endotracheal or tracheal tube. The offending tube should be removed and an oral endotracheal tube inserted. After treatment of any accompanying pneumothorax, the site should be evaluated under direct vision as the endotracheal tube is withdrawn proximal to the tracheotomy. If a tear is found, esophagoscopy is performed to insure the integrity of the esophagus. Repair of the tracheal wall is done with a single layer closure through the tracheotomy alternating suturing with ventilation. A generous tracheotomy, soft tubes and care in insertion of tubes into the trachea are suggested preventive measures.

Adult↗
PubMed1976

Laryngeal aortic baroreceptor pathways and cardiac arrhythmia.

This study was undertaken to confirm the effect of the ramus communicans baroreceptor pathway on cardiac rate during an upper-respiratory tract disturbance. The effects of destruction of this pathway were tested. It was found that cardiac rate could still be altered by stimulation of the main trunk of the superior laryngeal nerve, although the ramus communicans fibers were absent. Electrical stimulation of only the main trunk of the superior laryngeal nerve, but not any of its branches, is capable of causing cardiac changes. Cardiac changes also occur readily with mechanical stimulation of the area immediately superior to the vocal folds, despite bilateral destruction of the recurrent and superior laryngeal nerves. These findings question the proposed role of the laryngeal baroreceptor pathway as a major factor in the cause of cardiac changes related to intubation.

Animals↗
PubMed1975

Bovine graft arteriovenous fistulas for maintenance hemodialysis.

Modified bovine carotid artery grafts have been used for maintenance hemodialysis in 44 patients during an 18 month period. The technique of constructing an arteriovenous fistula in the leg and in the forearm is described. The common femoral artery and saphenous vein in the leg and the radial artery and basilic vein in the forearm are the preferred vessels. The complication rate has been low, consisting primarily of thrombosis and false aneurysms at the dialysis needle puncture site. Oversized grafts should be avoided because of resultant turbulent flow and the tendency of thrombosis. Bleeding after withdrawal of the hemodialysis needle must be properly controlled to minimize complications. Eighty-two percent have various problems and 18 per cent have failed. Bovine graft arteriovenous fistulas provide excellent vascular access in patients undergoing chronic hemodialysis.

Animals↗
PubMed1975

Interaction of mescaline with phenothiazines: effect on behavior, body temperature, and tissue levels of hallucinogen in mice.

Mescaline (25 mg/kg; 66 muc/kg) was injected (ip) in mice 45 min before chlorpromazine (CPZ, 2.5, 5, 15 mg/kg), thioridazine (10, 30, 45 mg/kg), or chlorpromazine-sulfoxide (CPZ-SO, 15 mg/kg). Excitement, agitation, slight increase in ventilation and occasional head-shaking were seen 30 min after mescaline and continued for 30-45 min thereafter; locomotor activity and the number of scratching events were significantly increased during this period. CPZ (2.5, 5, 15 mg/kg) and thioridazine (10, 30, 45 mg/kg) partially or completely blocked mescaline-induced gross behavior; CPZ-SO (15 mg/kg) was not effective. Increased scratching responses and locomotor activity induced by mescaline were antagonized by all doses of CPZ and thioridazine; at higher doses, both CPZ (7.5, 15 mg/kg) and thioridazine (45 mg/kg) induced cataleptic-like condition and marked hypothermia. Tissue levels of mescaline, examined 3 hr after its administration, were increased by all doses of CPZ and a higher dose of thioridazine (45 mg/kg); CPZ-SO and lower doses of thioridazine had no effect.

Animals↗
PubMedDate not supplied

Development of surgical quality-control mechanisms in large-scale prospective trials: head and neck intergroup report.

One of the current national prospective clinical trials of the Head and Neck Intergroup explores the usage of chemotherapy in advanced operable head and neck cancer patients. The experimental arm consists of the addition of 3 courses of cisplatin-containing chemotherapy to standard treatment defined as surgery followed by postoperative radiotherapy. In the design of the study it is necessary to define not only the extent of the surgery performed for each eligible lesion, but also to insure uniformity of surgery performed between surgeons and institutions. This will hopefully insure that any variation between the 2 arms of the study represent the effect of the chemotherapy. The procedure to obtain and confirm uniformity of surgery is multifaceted. It is, however, fundamentally based upon the current TNM staging system and therefore has intrinsic limitations.

Antineoplastic Combined Chemotherapy Protocols↗