Polyamines in brain tumor therapy

In the search for ways to augment current brain tumor therapies many have sought to exploit the fact that adult brain tissue is virtually lacking in cell division. This endorses a special appeal to therapeutic approaches which target the dependence on cell division for brain tumor growth. Polyamines play an essential role in the proliferation of mammalian cells and depletion results in inhibition of growth. As a result, there are investigations into the feasibility of controlling tumor growth by targeting the enzymes in polyamine metabolism with specific enzyme inhibitors. DFMO, an inhibitor of putrescine synthesis, is a cytostatic agent which in combination with tritiated radioemitters or cytotoxic agents such as, MGBG or BCNU is an effective antitumor agent, but the effectiveness of DFMO in vivo is reduced by tumor cell uptake of polyamines released into the circulation by normal cells and from gut flora or dietary sources. However, DFMO therapy combined with elimination of exogenous polyamines inhibits tumor growth but also results in body weight loss, reduced protein synthesis and evidence of toxicity. Furthermore, tumor growth recurs upon termination of treatment. In contrast, competitive polyamine analogs function in the homeostatic regulation of polyamine synthesis but fail to fulfill the requirements for growth and they continue to inhibit tumor growth for several weeks after cessation of treatment. Analogs are now in clinical trials. However, their action may be highly specific and differ from one cell type to another. We suggest that the effectiveness of polyamine based therapy would be enhanced by two approaches: local delivery by intracerebral microdialysis and tumor cell killing by internal radioemitters such as tritiated putrescine or tritiated thymidine which are taken up in increased amounts by polyamine depleted tumor cells. The growth inhibition by polyamine depletion prevents the dilution of the radioactive putrescine and thymidine. The overload of radioactivity kills the growth inhibited cells so that growth cannot recur when treatment terminates.

Crystalloid versus blood cardioplegia in coronary by-pass surgery. A prospective, randomized, controlled study in 100 consecutive adults

In a prospective randomized trial we investigated the benefit of blood versus asanguinous cardioplegia in routine coronary by-pass grafting. One hundred consecutive adult patients were randomly assigned to two groups: Group A (53 patients) received cold blood cardioplegia and group B (47 patients) had standard St. Thomas solution. In all patients we combined ante- and retrograde administration, in group A warm reperfusion was carried out before aortic declamping. Aortic cross clamp times, amount of cardioplegic solution and blood potassium levels at the end of cardio-pulmonary by-pass were higher in group A than in group B. The need for inotropic support at the end of the operation as well as in the postoperative period was more frequent in the crystalloid cardioplegia group. The occurrence of atrial fibrillation showed no clear correlation to the kind of cardioplegia used. Perioperative infarction was less frequent in the blood cardioplegia group (3.7% vs 6.3%; p < 0.01) and 30-day-mortality was nil (0% vs 3.2%; p < 0.01). Hospital stay did not differ between the two groups. In this clinical trial we could demonstrate the superiority of blood versus crystalloid cardioplegia in routine coronary by-pass grafting. Ante- and retrograde delivery of cold blood cardioplegia followed by warm reperfusion is a safe and simple method yielding satisfactory results.

"Stockless" cost reduction in the operating room

St. Paul-Ramsey Medical Center in St. Paul, MN became one of the first hospitals in the United States to initiate a "stockless" par level inventory system. Successes with stockless led the hospital to look at implementing it in the OR to achieve a reduction of expense to revenue. Materiel Management and Surgical Services discussed a number of issues relevant to implementing a stockless program, including product flow, accuracy and cost of case carts and preference cards, item pricing, committed usage of items brought into the system and establishment of a steering committee. Specific OR issues and practices required evaluation and adjustment, such as the routine use of emergency direct ordering. Information systems support was brought in and a products committee established to do education and oversee the program. Savings for 1993-94 were $185,146.

In vitro-lined endothelium: initial integrity and ultrastructural events

BACKGROUND

The early fate of in vitro-endothelialized prosthetic vascular grafts was assessed in the nonhuman primate.

METHODS

Each of 17 male chacma baboons received a control and a confluently endothelialized 4 mm polytetrafluoroethylene graft in femoro-femoral positions (8.2 +/- 0.8 cm). All experimental grafts were precoated with fibrinolytically inhibited fibrin glue and lined with cultured autologous endothelial cells (EC) from the external jugular vein. The average time period needed to obtain first-passage mass-cultures sufficient for preconfluent graft endothelialization was 19.8 +/- 5.2 days. Before implantation in vitro-lined grafts were kept in culture for another 16.1 +/- 4.3 days to achieve complete confluence and maturation of the EC cytoskeleton.

RESULTS

After 9 days of implantation, endothelial-lined grafts still showed a confluent endothelium that was free of any fibrin deposits. However, the EC density was significantly lower than at implantation (39.7 +/- 7.6 x 10(3) versus 59.9 +/- 8.5 x 10(3) EC/cm2; p < 0.05), and occasional 10-microns-wide intercellular gaps with adherent platelets and leukocytes were visible. Transmission electron microscopy showed leukocytes and cell debris in the underlying fibrin glue. After 4 weeks of implantation, the endothelium of experimental prostheses had regained a high cell density (72.7 +/- 10.5 x 10(3) EC/cm2) with a mature and well-differentiated morphologic appearance. At both observation periods, the surface of control grafts showed a wide range from fibrin deposits to an amorphous protein coverage containing spread platelets.

CONCLUSIONS

The endothelium of in vitro-endothelialized vascular prostheses remains confluent after implantation and is nonthrombogenic in spite of a moderate initial cell loss.

The role of the p53 gene in the malignant transformation of pleomorphic adenomas of the parotid gland

Pleomorphic adenoma (PA), the most common neoplasm of the parotid gland in adults, undergoes malignant transformation in only two to six percent of cases. In order to determine whether or not the p53 gene is involved in the malignant transformation of PA of the parotid gland, we have analyzed archival specimens from four patients with carcinoma ex-pleomorphic adenoma (CEPA) by immunohistochemistry and sequencing of the amplified DNA. Tissue specimens from each patient contained both the CEPA and the precursor PA. Immunostaining revealed that while all CEPA were p53 positive, only one of the four precursor PA was positive for p53. In this case, DNA was isolated from both the PA and CEPA and exons five through eight were amplified using the polymerase chain reaction. The same p53 mutation (single base substitution) was found in both the PA and the CEPA at codon 248. Adjacent normal tissue contained the wild-type p53 sequence. To our knowledge, this is the first report of the same p53 point mutation in both a PA and the associated CEPA of the parotid. These results strongly suggest a role for p53 gene mutation in the malignant transformation of some PA of the parotid gland.

Phase II study of neoadjuvant chemotherapy and radiation therapy with thoracotomy in the treatment of clinically staged IIIA non-small cell lung cancer

BACKGROUND

The purpose of this study was to assess the ability of administering to patients induction chemotherapy with carboplatin and etoposide (VP-16), followed by full-course radiation therapy and weekly carboplatin with tolerable toxicity as preoperative therapy to down-stage disease thus allowing the resection of clinically staged IIIA non-small cell lung cancer.

METHODS

Twenty-eight eligible patients with good performance status and previously untreated, marginally resectable stage IIIA non-small cell lung cancer received induction chemotherapy with carboplatin (dosed per the Egorin formulation), and VP-16 (100 mg/m2) followed by 6000 cGy of chest radiotherapy over six weeks administered concurrently with weekly doses of 100 mg/m2 of carboplatin. Patients who had either responsive or stable disease underwent thoracotomy, with attempted surgical resection of the primary lung lesion and the areas of abnormal adenopathy. Procedures involving less than a pneumonectomy were used whenever feasible.

RESULTS

Fifty-two cycles of induction chemotherapy were administered. The average initial dose of carboplatin was 407 mg/m2. Toxicity was tolerable with grade 3-4 neutropenia and/or thrombocytopenia in 48 and 27% of the patients. There were no septic deaths. Full-dose radiotherapy was administered to 82% of patients, with 73% receiving at least five weekly doses of carboplatin. The radiographically assessed response rate to the neoadjuvant treatment was 64% (partial response, 46%; minimal response, 18%). Sixteen patients underwent gross tumor resection with 12 (43%) having negative pathologic margins. Six patients had pneumonectomy. There were three perioperative deaths (19%); two were secondary to respiratory failure after the patients underwent a pneumonectomy. The median survival for all 28 patients was 15 months, and for the 16 patients undergoing thoracotomy was 23 months. Eight patients were alive and in remission, with follow-up ranging from 8 to 31 months.

CONCLUSIONS

The authors conclude that (1) carboplatin and VP-16, followed by full-dose radiotherapy with weekly carboplatin administration, is a well tolerated and effective regimen in the treatment of patients with marginally resectable stage IIIA non-small cell lung cancer; and (2) full-course radiotherapy can be administered before surgical resection without additional surgical morbidity or mortality.

Apparatus for high-precision repetitive sequential optical measurement of living cells

A system is described which permits the repetitive spectroscopic measurement of individual cells within a population of many cells, while the location of each cell is preserved during various manipulations of the cells and/or their surrounding medium. The central mechanical feature of the system is the cell carrier, a matrix of apertures in which the cells become trapped. The detector electronics operate in a preset photon counting mode, permitting the measurement of low and high light intensities with the same degree of precision. The present instrument configuration is specifically designed for the accurate and precise measurement of the polarization of fluorescence of probes within living cells for application to routine performance of the Cercek SCM test for cancer. With modifications, the apparatus can be applied to a wide range of other clinical and research tasks.

Prevalence of factor XII (Hageman factor) deficiency among 426 patients with coronary heart disease awaiting cardiac surgery

BACKGROUND

Several case reports of myocardial infarction in patients with factor XII deficiency have been published. In the present study we investigated the prevalence of this condition.

METHODS

Factor XII activity (one-stage clotting assay), fibrinogen (derived method), and lipoprotein (a) (enzyme-linked immunosorbent assay) were measured in the plasma of 426 consecutive patients with coronary heart disease awaiting cardiac surgery.

RESULTS

Among the 426 patients, 44 (10.3%) were found to be moderately deficient in factor XII (factor XII activity 17-50%, antigen 15-57%). The prevalence of factor XII deficiency was significantly higher (P < 0.0001) among patients with coronary heart disease than among 300 healthy blood donors (2.3%). Among coronary heart disease patients with this deficiency, elevated levels of fibrinogen, lipoprotein (a), and blood pressure were no more prevalent than in those without the deficiency; nor were cigarette smoking or a positive family history of thromboembolism more prevalent.

CONCLUSIONS

Coronary heart disease patients showed a 10% prevalence of factor XII deficiency. However, the pattern of atherosclerotic risk factors did not differ between patients with or without the deficiency.

Clinical in vitro endothelialization of femoropopliteal bypass grafts: an actuarial follow-up over three years

PURPOSE

The creation of an endothelial coverage on prosthetic vascular surfaces may improve the performance of synthetic small diameter vascular grafts. In vitro lining with cultured autologous endothelial cells offers a confluent endothelium at the time of implantation.

METHODS

Between June 1989 and December 1991, 49 patients who had no saphenous vein available entered the study. Indication for operation was disabling claudication in 37 patients and critical ischemia in 12 patients. With a random 1:2 assignment, 33 patients were admitted to the endothelialized group and 16 control patients received an untreated polytetrafluoroethylene prosthesis. Cultured autologous endothelial cells from the external jugular vein were confluently lined onto polytetrafluoroethylene grafts precoated with fibrinolytically inhibited fibrin glue. The follow-up was based on angiography, platelet labeling studies with indium 111-labeled oxine, assessment of the ankle-brachial index, and duplex sonography.

RESULTS

First-passage mass cultures of 16 million endothelial cells-required for the confluent lining of a 70 cm long 6 mm graft-were reached 25.1 +/- 11.2 days after vein excision. Growth failure occurred in 27.3%. After 32 months, the actuarial patency was 84.7% for endothelialized grafts and 55.4% for control grafts (p < 0.041 by Breslow test; p < 0.068 by Mantel-Cox test). The ankle-brachial index was continually diverging, reaching significantly lower values in the control group at 24 months (0.98 +/- 0.14 in the endothelialized group versus 0.70 +/- 0.12 in the control; p < 0.0023). The uptake of indium 111-labeled platelets--measured at 9 days, 3 months, 6 months, and 12 months--was significantly lower in the endothelialized group during the entire observation period.

In vitro endothelialization of a mesosystemic shunt: a clinical case report

The existence of a confluently covering endothelium that is free of any thrombotic appositions can be proved 30 days after clinical implantation of an in vitro endothelialized expanded polytetrafluoroethylene graft. The recipient of the mesosystemic H-graft was a 69-year-old man who had a thrombosed portal vein following pancreatitis. Autologous endothelial cells were obtained from the external jugular vein under local anesthesia, applying the in situ cannulation technique. After low-density plating, first-passage mass cultures of 1.22 x 10(6) endothelial cells were obtained 14 days after vein excision. After precoating was accomplished with fibrinolytically inhibited fibrin glue, a 10 mm expanded polytetrafluoroethylene graft was confluently lined with the autologous endothelial cells at a seeding density of 1.2 x 10(5) cells/cm2. After a maturation period of an additional 9 days and the microbiologic exclusion of a possible infection, an 11 cm graft segment was implanted between the superior mesenteric vein and the inferior vena cava. In spite of a patent shunt the patient had a repeat bleeding episode, needed parenteral nutrition, and died of sepsis on day 30. Immediately after the graft had been taken out, specimens were processed by scanning electron microscopy and light microscopy for the immunohistochemical proof of the endothelial nature of the surface-covering cell layer. The entire graft surface displayed a confluent cell lining that was free of any thrombotic appositions. A strongly positive stain result for both factor VIII-related antigen and the fixation-resistant CD34 molecule identified these cells as endothelial. No alpha-actin-positive cells could be detected. The underlying protein matrix was well preserved and unaltered in thickness and appearance, compared with preimplantation samples. None of the specimens showed any evidence of infection. This human demonstration of an intact endothelium on a patent venous prosthesis further establishes in vitro lining as a method that actually creates a persistent and functioning endothelium on a synthetic graft surface.

The influence of aortic valve prosthesis diameter on the reversibility of pulmonary hypertension in isolated aortic stenosis

Patients with pulmonary artery hypertension in the late course of isolated aortic stenosis are considered to have a poor prognosis. The aim of the following study was to determine the incidence of pulmonary artery hypertension, the postoperative course after valve replacement and the reversibility of pulmonary hypertension dependent on the valve prosthesis diameter. Seventy-six consecutive patients with symptomatic aortic stenosis undergoing isolated aortic valve replacement were studied. Preoperative right and retrograde left heart catheterization was performed in the cardiac catheterization laboratory. Three days after valve replacement, hemodynamic evaluation was repeated by a Swan-Gantz catheter. Patients with preoperative pulmonary hypertension (systolic pulmonary artery pressure > 30 mmHg, n = 53) differed significantly from patients without pulmonary hypertension (n = 23) with respect to systolic pulmonary pressure (52.4 +/- 17 vs. 24.3 +/- 4 mmHg), pulmonary capillary wedge pressure (22.3 +/- 10 vs. 8.8 +/- 2, p < 0.001), left ventricular end diastolic pressure (29.6 +/- 13 vs. 21.4 +/- 11) and valve area (0.64 +/- 0.10 vs. 0.79 +/- 0.11 cm2, p < 0.05). No difference was found with respect to age, maximum systolic transvalvular aortic gradient or cardiac output. Following valve replacement, the two groups did not differ significantly in fatal (2/53 vs. 1/23 or non-fatal (14/53 vs. 5/23) complications. In patients with pulmonary hypertension, systolic pulmonary pressure decreased from 52.4 +/- 17 to 38.9 +/- 6, diastolic pressure from 24.7 +/- 9 to 12.6 +/- 3, pulmonary capillary wedge pressure from 22.3 +/- 10 to 12.1 +/- 3, pulmonary capillary wedge pressure from 22.3 +/- 10 to 12.1 +/- 3 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)

Mucosal origin and shedding of an early colonic tumor marker defined by Adnab-9 monoclonal antibody

Recent attention has been drawn to the diagnostic potential of tests based on shed colonic tumor markers. Adnab-9 monoclonal antibody raised against neoplastic, potentially premalignant colonic adenomas recognizes a marker in colonic effluent or tissue which correlates with the presence of tumors or risk of colorectal cancer. The origin of this antigen and optimal collection of colonic effluent were investigated by enzyme-linked immunosorbent assay and Western blotting. Mean Adnab-9 binding in effluent samples from colorectal cancer patients even after resection is high as compared with that in normal subjects (P < 0.05). Effluent samples are best collected in the morning hours. Antigen proteolysis may be significant depending on the site and timing of effluent collection, but breakdown products are reactive. Tissue and effluent Adnab-9 binding at any one anatomic site of collection appear to correlate (r = 0.88, P = 0.01). The Adnab-9 antigen is constitutively expressed at low levels throughout the distal bowel and localized to the deepest regions of the mucosal crypts. Other than meconium, no significant levels of binding are found in other body fluids. This antigen is specific for the gastrointestinal tract, its binding in conveniently collected effluent samples correlates with tissue content, and the antigen is constitutively expressed in the crypts of the distal small bowel and colonic mucosa.

Surface Tension Measurements of Surface Freezing in Liquid Normal Alkanes

Surface tension measurements reveal surface freezing in liquid n-alkanes. A solid monolayer of molecules is found to exist up to 30 degrees C above the bulk freezing point. This surface phase exists only for carbon numbers 14 n </= 50. The measured carbon number and temperature dependence of the surface tension is interpreted within a simple thermodynamical model based on known bulk latent heat data and surface energy considerations. The vanishing of the surface phase for n </= 14 is a possible transition from surface freezing to surface melting behavior.

Improved zipper closure of the abdominal wall in patients requiring multiple intra-abdominal operations

Optimal management of pancreatic abscess and septic complications of acute pancreatitis remains controversial. With the "open packing" approach, repeated closure of the midline fascia is complicated by loss of tissue integrity and suture strength. An improved zipper closure of the abdominal wall in six patients with pancreatic abscess is presented. Improvements included: (1) using a separating jacket-type zipper to allow maximal intraoperative exposure; (2) employing a removable tuck for expansion of the patch covering the wound; (3) substituting a nonmeshed polytetrafluoroethylene material for the polypropylene mesh to prevent adherence to the underlying viscera; and (4) creating a flap underneath the zipper teeth to protect the underlying tissue from injury. Satisfactory results were achieved with the improved zipper technique.

Lumpectomy compared with lumpectomy and radiation therapy for the treatment of intraductal breast cancer

BACKGROUND AND METHODS

Women with ductal carcinoma in situ have been treated both by lumpectomy and by lumpectomy followed by radiation therapy, but the benefit of combined therapy is uncertain. A group of 818 women with ductal carcinoma in situ were randomly assigned to undergo lumpectomy or lumpectomy followed by breast irradiation (50 Gy). Sufficient tissue was removed that the margins of the resected specimens were histologically tumor-free. The mean duration of follow-up was 43 months (range, 11 to 86). The principal end point of the study was event-free survival, as defined by the presence of no new ipsilateral or contralateral breast cancers, regional or distant metastases, or other cancers and by no deaths from causes other than cancer.

RESULTS

Five-year event-free survival was better in the women who received breast irradiation (84.4 percent, vs. 73.8 percent for the women treated by lumpectomy alone; P = 0.001). The improvement was due to a reduction in the occurrence of second ipsilateral breast cancers; the incidence of each of the other events was similar in the two groups. Of 391 women treated by lumpectomy alone, ipsilateral breast cancer developed in 64 (16.4 percent); it was noninvasive in 32 and invasive in the remaining 32. Of 399 women treated with lumpectomy and breast irradiation, ipsilateral breast cancer developed in 28 (7.0 percent) (noninvasive in 20 and invasive in 8). The five-year cumulative incidence of second cancers in the ipsilateral breast was reduced by irradiation from 10.4 percent to 7.5 percent for noninvasive cancers and from 10.5 percent to 2.9 percent for invasive cancers (P = 0.055 and P < 0.001, respectively).

CONCLUSIONS

Breast irradiation after lumpectomy is more appropriate than lumpectomy alone for women with localized ductal carcinoma in situ.

[Long-term results of percutaneous atherectomy in peripheral arterial occlusive disease]

In a retrospective study the indications and the long-term results of percutaneous atherectomy of a nonselected group of patients were analysed. From March 1988 to November 1989, 94 patients suffering from peripheral vascular disease were treated using Simpson's atherectomy technique. There were 132 lesions, 101 stenoses and 31 occlusions in a total of 94 patients. The primary success rate was 95%. After 12 months of follow-up the cumulative patency rate was 69% and after 24 months, 42%. After a follow-up period of 15 months patent arteries and recurrences were recorded and the results used to analyse the factors that influence patency after Simpson atherectomy. The patency rate is 71% in diabetics and 62% in non-diabetics. It is 51% in occlusions and 73% in stenoses. The patency rate in patients with fair runoff is 69%, in patients with poor runoff 60%. Comparing these results with historical studies concerning balloon dilation the results are poor. Residual stenoses after balloon dilation seem to be the optimal indication for percutaneous atherectomy.

Effect of D,L-alpha-difluoromethylornithine (DFMO) enhanced [3H]putrescine uptake on 9L tumor cell growth and colony forming efficiency

PURPOSE

This study explored the possible use of D,L- alpha-difluoromethylornithine (DFMO) to enhance the uptake of [3H] putrescine in order to selectively kill brain tumor cells.

METHODS AND MATERIALS

Gliosarcoma cells (9L) were grown for 4 or 20 day periods in monolayer cultures with or without [3H] putrescine and/or DFMO. Cells in culture incubated for 20 days were replated at 4-day intervals. Cells were counted on a Coulter Electronic Particle Counter and percent viability was determined by eosin dye exclusion. Survival of cells with proliferative capacity was assayed by their colony. Forming ability and surviving fraction was calculated. The radioactive counts due to [3H] putrescine were measured in 9L cells and in medium and expressed as cpm/100 cells or cpm/ml, respectively.

RESULTS

As previously reported (15), DFMO treatment resulted in termination of cell proliferation that was reversible by the addition of exogenous putrescine. Specifically, after 4 days in culture, cell counts in groups exposed to 10 mM DFMO were 55% of those in control groups and addition of 3 mM putrescine reversed the DFMO effects. Uptake of [3H] putrescine into untreated cells increased in proportion to the amount of exogenous putrescine present during 4 days of culture (range 0.01 nmol to 100 nmol) and the presence of DFMO in the medium enhanced the uptake 9 fold throughout these ranges. At activities greater than 100 cpm/100 cells the cell count was reduced to 23 to 48% of control after 4 days in culture. Extending the treatment to 20 days of incubation increased the killing of 9L cells. During the 20-day incubation, control cells increased from 5 x 10(5) to 13 x 10(12) of which 90% were colony forming cells. Treatment with either 25 microCi [3H] putrescine or 1 mM DFMO for 4 days followed by removal of these agents and incubation for an additional 16 days for a total of 20 days resulted in 31 x 10(8) or 18 x 10(7) colony forming cells, respectively. Combining [3H] putrescine and DFMO treatments during the first 4 days of the 20 day incubation reduced the colony forming cells to 21 x 10(5) (surviving fraction to 67%). When the DFMO treatment was present during the entire 20 days, it became cytotoxic since the colony forming cells were reduced to 35 x 10(3) (surviving fraction was 17%). The combination of the 4-day [3H putrescine and the 20 day DFMO treatments resulted in only 1200 surviving colony forming cells (surviving fraction was only 2%).

CONCLUSION

DFMO treatment of 9L cells for 20 days resulted in increased uptake of [3H] putrescine, a 10(10) fold inhibition of colony forming cells and extensive 9L cell killing relative to untreated controls.