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Biomedical subjects

R Zajtchuk

Publications and source records attributed to R Zajtchuk.

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

The use of computed tomography in the evaluation of mediastinal masses.

A retrospective analysis was conducted to ascertain whether computed tomography had increased diagnostic accuracy while decreasing the number of tests needed in the preoperative assessment of patients with mediastinal masses. A total of 42 patients were entered into the study: Fifteen patients were evaluated before the advent of computed tomography (No CT) and 27 patients had computed tomography during their evaluation (CT). The No CT group comprised 10 male and five female patients (2:1 ratio); the age range was 8 months to 61 years. The CT group included 15 male and 12 female patients (1.25:1.0 ratio), the age range being 21 to 70 years. In each group, both invasive and noninvasive studies were done. Although the CT group had 40 noninvasive tests, 27 were computed tomographic scans. The additional 13 noninvasive tests and the five invasive tests added no significant diagnostic information. In the No CT group, preoperative evaluation as to the cystic or solid nature of the mass was correct only four of 13 times (31%). In the CT group, 22 of 25 patients had accurate assessment as to the cystic or solid nature of the lesions (88%). In addition, extension of the mass into other structures, consistent with malignancy, was correctly diagnosed preoperatively in nine of the patients in the CT group. Two had extension of the mass at operation not preoperatively diagnosed (82% accuracy). None of the No CT group was given an assessment of possible mass extension preoperatively. The results suggest that mediastinal masses can be evaluated by computed tomography with a high degree of accuracy for predicting the nature, size, location, and involvement of other organs by the mass. The use of other tests before resection generally yields little additional information.

Adolescent↗
PubMed1985

A longitudinal evaluation of thyroid function in critically ill surgical patients.

Thyroid hormone alterations (known as the "sick-euthyroid syndrome") are common following major surgery, but the time course for appearance and recovery from these alterations has not previously been longitudinally studied in a large group of surgical patients. The authors prospectively studied 59 patients undergoing major surgery (coronary artery bypass grafting, pneumonectomy, or subtotal colectomy). Compared with preoperative values, the mean serum T4, T3, free T3, and TSH concentrations decreased significantly (p less than 0.05) following surgery. Serum reverse T3 and T3 resin uptake index increased, while free T4 levels remained unchanged. These changes were seen within 6 hours of surgery and normalized by 1 week after surgery. Although the serum TSH response to TRH was normal before and after surgery in 56 of the 59 patients, the maximal TRH-induced increase in serum TSH and the integrated serum TSH response to TRH were suppressed in the early perioperative period. This postoperative TSH suppression correlated with elevated postoperative plasma dopamine concentrations (r = 0.57, p less than 0.05). Three patients with compensated primary hypothyroidism were detected in the study and represent the first documentation of serial thyroid hormone and TSH levels in hypothyroid patients undergoing major surgery. These patients had similar changes in thyroid hormone values compared with euthyroid patients. The serum TSH response to TRH was suppressed into the normal range in two of these patients on the day following surgery. The authors conclude that the sick-euthyroid syndrome occurs within a few hours of major surgery and remits with convalescence. Postoperative decreases in serum TSH may mask the diagnosis of hypothyroidism. Surgical consultants should be aware of these rapid postoperative changes so that thyroid function tests are properly interpreted in patients who have undergone major surgery.

Adult↗
PubMed1985

Rib fracture healing in experimental flail chest.

Sixteen dogs were placed under general anesthesia and flail segments of the left chest were created by transecting ribs 7,8,9, and 10 anteriorly and posteriorly. Fractures were 10 cm apart so that a 10-cm flail segment encompassing four ribs was created. In Group I, the control (N = 5), the chest wall muscles were closed without any stabilization of the fractures. Group II (N = 5) had stabilization of both anterior and posterior fracture sites by polypropylene sutures. Group III (N = 6) had stabilization of the fractures in ribs 7 and 8 with 2.5-cm bone grafts taken from the left fourth rib. Ribs 9 and 10 were stabilized by polypropylene sutures. The study established a canine model for flail chest. It also showed that strut stabilization of rib fractures with bone grafts promotes better healing than suture stabilization. It suggests that using bone grafts taken from another rib to stabilize flail segments may be unsatisfactory since the rib used as a donor showed no signs of regeneration at 30 days.

Animals↗
PubMed1985

Creatine kinase and lactate dehydrogenase in the muscles encountered during median sternotomy and in the myocardium of the cardiac chambers.

The validity of using creatine kinase MB and lactate dehydrogenase serum isoenzymes to confirm the diagnosis of perioperative myocardial infarction in patients who have had cardiac operations has been questioned, since both have been detected in skeletal muscles. Little is known concerning the concentration of either isoenzyme in the muscles routinely encountered during median sternotomy. Since we have previously shown that the dog is an adequate model in which to study creatine kinase and lactate dehydrogenase isoenzymes, eight healthy dogs were placed under general anesthesia and 1 gm blocks were resected from selected muscles (intercostals, rectus abdominis, diaphragm, and sternothyroid) and from the walls of all four cardiac chambers. Each 1 gm block was homogenized individually in Ringer's lactate, centrifuged, and the supernatants were analyzed for total creatine kinase and lactate dehydrogenase activity by spectrophotometry. Isoenzymes were determined by agarose gel electrophoresis. The study shows that the chest wall muscles and atrial myocardium have appreciable quantities of creatine kinase MB. Hence, serum creatine kinase MB bands in the perioperative period can be generated by manipulation of chest wall muscles and the atrial wall as well as by infarction of the ventricular myocardium.

Animals↗
PubMed1984

Radiation associated malignancies of the esophagus.

This report documents the experience of the authors with two patients who had received thoracic radiation for disseminated teratocarcinomas of the testis, survived their malignancies, and subsequently developed squamous cell carcinomas of the esophagus. To the authors' knowledge, only 11 other cases of esophageal malignancies arising in patients who had received previous mediastinal irradiation have been reported in the world literature. With increasingly successful mediastinal radiation for malignant disease resulting in prolonged patient survival, an increasing number of such patients with subsequent esophageal malignancies can be anticipated. Close follow-up of patients receiving radiation therapy to periesophageal tissues is recommended, and prompt evaluation of any symptoms of esophageal dysfunction is indicated.

Adult↗
PubMed1984

Adult human saphenous vein endothelial cells: assessment of their reproductive capacity for use in endothelial seeding of vascular prostheses.

Autogenous endothelial seeding (AES) of vascular prostheses (VP) using venous endothelial cells (EC) reduces platelet-VP interactions and improves patency rates in small caliber VP in dogs. To conserve patients' veins for use in coronary or limb bypass surgery, human trials of AES should require proof that adequate numbers of EC with the growth capacity to cover VP can be harvested from acceptably small pieces of peripheral vein. EC were isolated from excess saphenous vein segments remaining after coronary bypass surgery by filling veins with 0.1% CLS II collagenase at 37 degrees C for 15 min and removing EC by flushing the veins with culture medium. EC were cultured on fibronectin-coated dishes in medium 199 with 30% human serum and 300 micrograms/ml of endothelial cell growth factor. These cells grew to form confluent monolayers, and were identified as EC by tests for factor VIII antigen. Veins from 53 patients with a mean age of 55.8 +/- 9.8 (SD) years yielded vein segments with an average area of 1.9 +/- 0.6 cm2, from which an average of 5.3 +/- 2.8 X 10(4) cells were removed per cm2 of vein area. EC in culture underwent 14.3 +/- 1.4 population doublings with an average population doubling time of 1.8 +/- 0.3 days (N = 14 cultures), which allowed an 100-fold increase in cell number to occur in 11 to 12 days. These data suggest that the EC available from small vein segments in adult humans have the growth capacity to cover areas comparable in size to the luminal areas of VP commonly used in arterial surgery.

Adult↗
PubMed1984

An alternate method of ventricular venting--the pulmonary artery sump.

The need for venting the heart during cardiopulmonary bypass has been the topic of continued debate. Potential disadvantages and drawbacks have been noted with traditional modes for venting. A technique for venting the heart is presented using a pulmonary artery catheter. The relative advantages and merits of this approach are discussed.

Cardiac Catheterization↗
PubMed1984

Diagnostic dosages of protirelin (TRH) elevate BP by noncatecholamine mechanisms.

While performing thyroid function tests, we noticed that protirelin (TRH) raised BP, and, therefore, we investigated the effect of diagnostic dosages of protirelin (500 micrograms) on plasma catecholamine levels and cardiovascular function in eight patients one day before, one day after, and four weeks following heart surgery. Mean arterial pressure (MAP), heart rate (HR), plasma norepinephrine (NE), epinephrine (EPI), dopamine (DA), thyroid hormone (triiodothyronine [T3], thyroxine), and thyrotropin (TSH) levels were measured before and after the intravenous injection of protirelin. Protirelin increased MAP transiently from 88 +/- 2 to 103 +/- 3 mm Hg (before surgery), 86 +/- 4 to 102 +/- 4 mm Hg (one day after surgery), and 86 +/- 4 to 104 +/- 5 mm Hg (four weeks after surgery). There were no notable changes in HR or plasma NE, EPI, or DA levels. The T3 and TSH response to protirelin was normal on all three study days. Protirelin raised MAP by an effect on systemic vascular resistance (SVR) rather than an increase in cardiac output. We conclude the following: (1) diagnostic dosages of protirelin transiently elevate MAP and SVR by a noncatecholamine mechanism, (2) clinicians who perform protirelin tests should be aware of protirelin's transient pressor effects.

Adult↗
PubMed1984

Cystic lesion of the thymus. An occasionally malignant cervical and/or anterior mediastinal mass.

Between 1965 and 1982, we treated 46 patients with cystic lesions of the thymus. Thirty patients had anterior mediastinal cysts, nine had cysts which were large enough to be both cervical and mediastinal, and seven had cervical cysts. The majority (40/46) presented with asymptomatic masses. Six patients presented with distinct complaints: dysphagia (four patients), hoarseness owing to vocal cord paralysis (one patient), and cervical pain (one patient). All six had benign thymic cysts. The diagnosis of a cystic mass was established prior to operation by ultrasonography and computed axial tomography in our last three patients. These two techniques delineated the capsule and the central fluid in those three cases. All 46 patients had the mass resected without mortality or significant morbidity, except for resection of the phrenic nerve in one patient with malignant cystic thymoma. Cervical cysts were excised through cervical incisions. Cysts located in the anterior mediastinum and cervical-mediastinal cysts required median sternotomy or right thoracotomy for successful resection. Pathological examination showed that 39 patients had benign thymic cysts, three had benign cystic thymoma, two had malignant thymoma, one had a seminoma arising in the thymus, and one had a lymphoblastoma. We believe that a cystic thymic mass which can be detected by ultrasonography and computed tomography, although usually benign, does not eliminate the possibility of malignancy, and resection, therefore, is indicated.

Adolescent↗
PubMed1984

Management of patients with malignant thymoma.

This report documents the results of therapy in 23 patients treated for malignant thymoma between 1944 and 1979. Of the group, 22 patients had neoplasms which invaded mediastinal structures; six had distant metastases. Four patients had myasthenia gravis and one had erythroid hypoplasia associated with collagen vascular disease. No deaths were associated with primary therapy, which included an operative procedure in all cases. Follow-up ranged from 4 months to 18 years (mean 5.63 +/- 1.03 years, SEM). Fifteen patients died, with postoperative survival times ranging from 4 months to 18 years (mean 3.8 +/- 1.27 years). Five patients were alive without recurrence from 3 to 11 years postoperatively (mean 6.8 +/- 1.36 years), and three patients were alive with recurrence or distant metastases from 4 to 17 years postoperatively (mean 10.75 +/- 2.66 years). Differences in survival on the basis of tumor cell type were not statistically significant. Therapeutic groups were analyzed for 5 year survivors, tumor deaths within 5 years of therapy, deaths due to other causes, deaths due to tumor after 5 years, those presently alive, and longest known survivor. The data suggest that complete surgical excision offers the best chance of long-term survival when compared to partial resection plus irradiation (p less than 0.05). No statistical significance could be demonstrated between the groups who had complete resection with versus without postoperative irradiation. There also was no statistically significant difference between the group of patients receiving irradiation following partial excision of most of their tumor and the group receiving irradiation following only biopsy of the lesion. This observation suggests there is no value in so-called "debulking procedures" and suggests that irradiation may be of value in local control of thymoma. Perpetual surveillance is necessary since late recurrence is common.

Adolescent↗
PubMed1983

Relationship of triglyceride levels to thrombosis in patients with coronary artery disease.

The relationship of triglyceride levels to coagulation abnormalities was studied in 43 patients, who were divided into two groups. Group 1 consisted of patients with triglyceride levels less than 200 mg% (range, 75 to 190 mg%), and Group 2 consisted of patients with triglyceride levels greater than 250 mg% (range, 255 to 890 mg%). Analysis of the data revealed that patients with high triglyceride levels also have a high incidence of low antithrombin III activity and increased platelet aggregation. It is likely that hyperlipidemic patients are more prone to thrombosis of diseased coronary arteries or saphenous vein bypass grafts, and should definitely be placed on appropriate anticoagulants.

Adult↗
PubMed1983

Comparison of cephalothin and ceforanide prophylaxis in cardiac surgery with cardiopulmonary bypass.

Eighty-five patients undergoing cardiac surgery with cardiopulmonary bypass were given either cephalothin or ceforanide perioperatively in randomized, blinded fashion. The incidence of surgically related, postoperative infections was 23% for the cephalothin- and 26% for the ceforanide-treated groups. There were no statistically significant differences that could be identified between patients who became infected and those who remained free of infections, although the time spent in the operating theater was longer for the former group. Ceforanide achieves adequate levels in plasma and myocardial tissue that are sustained several hours after a 0.5-g parenteral dose and allows a 12-h interval between doses. Other currently available agents would have to be administered more frequently to achieve similar results.

Cardiac Surgical Procedures↗
PubMed1982

Initial and long-term results in the management of primary chest wall neoplasms.

One hundred ten patients with primary chest wall neoplasms were analyzed for long-term results. The diagnosis of 59 malignant and 51 benign tumors was confirmed by the Armed Forces Institute of Pathology. No deaths were associated with primary definitive therapy. Among the five most frequently encountered malignant tumor types, five-year survivals were obtained in 9 of 17 (53%) patients with fibrosarcoma, 8 of 9 (89%) patients with chondrosarcoma, 2 of 8 (25%) patients with solitary chest wall plasmacytoma (multiple myeloma), 1 of 6 (17%) patients with Ewing's sarcoma, and 2 of 4 (50%) of patients with osteogenic sarcoma. Although the five-year survival appears to indicate therapeutic success in patients with Ewing's sarcoma and osteogenic sarcoma, patients with chondrosarcoma or fibrosarcoma may have a more protracted course, and those with solitary plasmacytoma usually develop multiple myeloma. The findings suggest that radical surgical excision is the treatment of choice for chondrosarcoma; radical surgical excision combined with chemotherapy, for fibrosarcoma and osteogenic sarcoma; surgical excision combined with radiation and chemotherapy, for Ewing's sarcoma; and systemic surveillance and therapy, for pathologically confirmed solitary plasmacytoma.

Adolescent↗
PubMed1982

Diaphragmatic paralysis managed by diaphragmatic replacement.

A neonate had paralysis of the right hemidiaphragm secondary to brachial plexus birth trauma. Conventional diaphragmatic plication, performed on two separate occasions, failed to correct the ventilatory impairment, and mechanical ventilatory dependence persisted. Ventilatory insufficiency was subsequently corrected by total replacement of the right hemidiaphragm with Marlex mesh. This procedure ablated paradoxical motion of the right hemidiaphragm and arrested detrimental shifts of the mobile infantile mediastinum. The good result was immediate and long-lasting; there was no major prosthesis-related growth deformity 31/2 years later. Prosthetic fixation of the paralyzed diaphragm is not indicated as a primary procedure, but should be reserved for the occasional patient in whom conventional plication has failed.

Birth Injuries↗
PubMed1981

An analysis of the isoenzymes of creatine phosphokinase and lactic dehydrogenase in the esophagus.

Surgical manipulation of muscular organs can cause alterations of the serum isoenzymes of creatine phosphokinase (CPK) and lactic dehydrogenase (LDH), which are frequently used to confirm the diagnosis of myocardial infarction (MI). Since the content of these enzymes and their isoenzymes has not been established for the esophagus, an experiment was conducted to evaluate and compare the enzymes in postmortem specimens from humans and fresh canine specimens. One gram transmural esophageal sections were taken from specimens having no demonstrable disease. All samples were homogenized individually in Ringer's lactate solution and centrifuged, and the supernatants were analysed for the respective isoenzyme distributions by agarose gel electrophoresis. From the study we drew the following conclusions: (1) all three isoenzymes of CPK (including CPK-MB, the myocardialisoenzyme) are present in the esophagus; (2) LDH, the isoenzyme of LDH most prevalent in myocardium, is the least common of the five isoenzymes of LDH in the esophagus; (3) the dog is an appropriate model for studying changes of these isoenzymes after operation; and (4) any potential confusion in diagnosing postoperative MI due to esophageal CPK-MB in the serum can be resolved, theoretically, by analyzing LDH serum isoenzymes. In myocardial infarction, LDH becomes the predominant isoenzyme, whereas esophageal injury should be associated, theoretically, with a serum LDH isoenzyme pattern in which LDH is the least prevalent isoenzyme.

Adult↗
PubMed1981

Dipyridamole-aspirin as thromboembolic prophylaxis in patients with aortic valve prosthesis. Prospective study with the Model 2320 Starr-Edwards prosthesis.

In a prospective study, the efficacy of a dipyridamole-aspirin regimen in prevention of thromboembolism was evaluated in 50 patients having isolated aortic valve replacement with the Model 2320 Starr-Edwards prosthesis. These operations were performed between February, 1972, and October, 1974. In 1,380 patient-months of follow-up, there was a 20% incidence of thromboembolism with a rate of 8.7/100 patient-years and a 19% probability of an embolic episode occurring by 3 years. Seven patients had transient episodes, two had permanent neurologic residua, and one patient died. Comparison is made to a similar group of patients having solitary aortic valve replacement but receiving no medication, studied by Starr and associates. There was no statistical difference in the incidence of thromboembolism between the two groups. In November, 1975, all patients were converted to a regimen of warfarin therapy. Since conversion to anticoagulation, there have been two thromboembolic episodes in 2,132 patient-months of follow-up for a rate of 1.1/100 patient-years. We conclude that the use of antiplatelet therapy in the form of dipyridamole-aspirin is inadequate for routine thromboembolic prophylaxis following SE 2320 aortic valve replacement.

Adult↗
PubMed1980

A comparison of serum isoenzyme levels of creatine phosphokinase and lactic dehydrogenase in patients undergoing thoracic operations and patients admitted to a coronary care unit.

A prospective study comparing patients undergoing major thoracic surgical procedures with patients admitted to a coronary care unit was conducted. Surgical patients having bronchoscopy and mediastinoscopy (n = 12), anterior thoracotomy (n = 12), and posterolateral thoracotomy (n = 22) were compared with patients in the coronary care unit who had electrocardiographically proved myocardial infarctions (MI) (n = 11) and those with no electrocardiographic abnormalities (n = 12). Sera were studied by spectrophotometric analysis (creatine phosphokinase [CPK] and lactic dehydrogenase [LDH]), agarose gel electrophoresis (CPK and LDH), and antibody inhibition spectrophotometric analysis (CPK). The levels of total CPK did not rise above the upper limits of normal (100 IU/L) in patients who underwent bronchoscopy and mediastinoscopy. Total CPK elevations in patients undergoing thoracotomy (anterior thoracotomy, 428 +/- 62 IU/L [mean +/- standard error of the mean]; posterolateral thoracotomy, 652 +/- 78 IU/L) were not significantly different from those sustaining acute MIs (463 +/- 84 IU/L). Only transient minimal elevations of CPK-MB isoenzyme were noted, however, in the patients having posterolateral thoracotomy (25 +/- 7 IU/L). These were significantly lower (p < 0.001) than the elevations seen in patients sustaining acute MIs (80 +/- 16 IU/L). In none of the surgical patients did LDH1 exceed LDH2 while all of the patients with MIs had such a shift (p < 0.001). The data support the conclusion that the serum isoenzymes of CPK and LDH are capable of confirming the diagnosis of MI in patients recovering from major thoracic surgical procedures.

Adult↗