Percutaneous placement of an implantable arm port through an internal mammary venous pathway: Case report.

Current chemotherapeutic regimens often require long-term central venous access for their administration. Obtaining a durable form of vascular access in patients with recurrent cancer can be a challenge due to direct tumor involvement and prior surgical, chemotherapeutic or radiation therapy. We describe a case of a peripherally inserted access port in a patient with recurrent head and neck cancer, in whom radiation therapy planned for metastatic mediastinal disease prevented placement of a chest port. At the time of port implantation, venography revealed central venous occlusion. Using mediastinal venography, a collateral pathway to the superior vena cava was identified between the left and right internal mammary veins. By employing this technique, an arm port system was successfully navigated through the collateral pathway percutaneously with the tip of the port tubing placed at the cavoatrial junction. This case illustrates technical nuances and emphasizes the importance of thorough venography when attempting to achieve difficult vascular access.

Pilot study of organ preservation multimodality therapy for locally advanced resectable oropharyngeal carcinoma.

The purpose of this study was to determine the early efficacy and toxicity of a new multimodality organ-preservation regimen for locally advanced, resectable oropharyngeal squamous cell carcinoma (SCC). Patients with T3-4N0-3M0 or T2N2-3M0 oropharyngeal SCC were eligible for this Phase II study. Patients needed the physiologic reserve for surgery and technically resectable tumors. Induction carboplatin (area under the curve = 6) and paclitaxel (200 mg/m2) x 2 cycles (q21 days) were given. Objective responders received definitive radiotherapy (XRT), 70 Gy/7 weeks with concurrent weekly paclitaxel. Initially, the dose of paclitaxel was 50 mg/m2/week; because of mucosal toxicity it was reduced to 30 mg/m2/week. Patients with N2-3 disease received post-XRT neck dissection and 2 more cycles of "adjuvant" chemotherapy. In the first 22 patients, the neutropenic fever rate was 27%. Although there has been no grade IV-V toxicity from induction therapy, grade II-III toxicity resulted in an unacceptable delay in starting XRT in 14% of patients. The response rate to induction chemotherapy was 91%. Grade III mucositis occurred in all patients during concurrent chemoradiotherapy. One patient died of pneumonia during concurrent chemoradiotherapy after receiving 26 Gy and 3 doses of paclitaxel 50 mg/m2. No dose-limiting toxicity occurred in 15 patients treated with concurrent paclitaxel 30 mg/m2/week. Actuarial overall survival at 18 months is 82%; local-regional control is 86%. To date, distant metastases have not developed in any patients. This regimen has intense but acceptable acute toxicity. The maximum tolerated dosage of weekly paclitaxel during standard continuous-course XRT is confirmed to be 30 mg/m2/week. The treatment efficacy of this regimen (response rate and short-term local-regional and distant control) is encouraging. Accrual continues to obtain long-term toxicity, efficacy, and quality-of-life data.

Effects of adinazolam on plasma catecholamine, heart rate and blood pressure responses in stressed and non-stressed rats.

Adinazolam (ADI) is a new benzodiazepine with anxiolytic and antidepressant properties. To assess its effects on the acute stress response, rats were given a single intraperitoneal injection of 2.5 or 5.0 mg/kg of ADI and stressed for 1 hr by restraint. Neither dose of ADI had any effect on heart rate, blood pressure or norepinephrine (NE) and epinephrine (EP) in plasma in the resting rats. In the stressed animal, 2.5 and 5.0 mg/kg of ADI did not affect stress-induced increases in heart rate or blood pressure but both significantly reduced the stress-induced increases in plasma NE and EP. During certain stressful experiences in patients with abnormally-increased sympathetic drive, ADI may be therapeutically useful in reducing high levels of catecholamines.

The effects of immobilization stress on serum triglycerides, nonesterified fatty acids, and total cholesterol in male rats after dietary modifications.

The effects of acute immobilization stress on triglycerides, nonesterified fatty acids (NEFA) and total cholesterol were determined in serum samples obtained by indwelling jugular catheters from male Sprague-Dawley rats. Stress was evaluated in three groups of rats: (1) those maintained on a regular Purina Chow diet and then fasted for 24 hours; (2) those maintained on this same diet but not fasted (nonfasted) before experimentation; and (3) those maintained on a Purina Chow diet supplemented with cholesterol (1%) and fat (10%) for 6 weeks and nonfasted prior to experimentation. Samples were taken by catheter in the home cage prior to, four times during a one hour stress/nonstress period and thirty minutes after being returned to the home cage for recovery. Nonstressed rats remained in the home cage during the entire 90 minute period. In each dietary state studied, stress affected serum triglycerides and NEFA but not total cholesterol levels. Triglyceride levels in fasted rats increased during the stress period. On the other hand, triglycerides decreased in response to stress in nonfasted rats. In stressed, nonfasted high cholesterol-fed animals, triglycerides were elevated in comparison to their nonstressed counterparts. In both fasted, regular diet-fed and nonfasted, cholesterol-fed rats, NEFA sharply declined from baseline after 5 minutes of stress; NEFA did however increase after fifteen minutes. NEFA levels in both stressed and nonstressed, nonfasted rats also rapidly decreased from baseline and never recovered throughout the session. Total cholesterol did not change in response to stress or dietary modifications. The rats maintained on a high cholesterol diet showed only a diet-induced increase in total cholesterol. Thus, acute immobilization stress affected serum triglyceride and NEFA values and these effects were diet- and time-dependent. Total cholesterol levels were unaffected by stress.

Fibrinogen interaction with platelets of diabetic subjects.

Fibrinogen-platelet interaction was studied in suspensions of platelets obtained from patients with uncontrolled diabetes mellitus of long duration and from control individuals. Fibrinogen binding sites were exposed by stimulating platelets with ADP or with chymotrypsin. There was no significant difference in fibrinogen mediated aggregation between ADP-stimulated platelets of 80 control and 47 diabetic subjects. The Km values for fibrinogen mediated aggregation of ADP-stimulated platelets obtained from control and diabetic donors were 1.39 +/- 0.13 X 10(-7)M and 1.44 +/- 0.13 X 10(-7)M; the Vmax values (expressed in arbitrary light transmission units) were 87.8 +/- 3.14 and 92.8 +/- 4.5 (mean +/- S.E.M.). The analysis of variance showed no significant relationship between Km, Vmax, age and sex in control group; in patient group there was no significant relationship between Km, Vmax, age, sex, type of diabetes, presence of vascular complications and type of treatment (insulin and/or oral hypoglycemic agents). Fibrinogen mediated aggregation of chymotrypsin-treated platelets showed similar pattern in 25 control and in 25 diabetic donors. In 24 normal individuals and in 24 diabetic patients Scatchard analysis revealed 48,820 +/- 5350 fibrinogen binding sites per one normal platelet (Kd = 4.7 X 10(-7)M) and 45,350 +/- 4663 sites per one diabetic platelet (Kd = 3.5 X 10(-7)M). Our data suggest a normal pattern of interaction between fibrinogen and fully activated platelets of diabetic subjects.

Quantitation and characterization of human platelet glycoprotein IIIa by radioimmunoassay.

Glycoprotein IIIa was quantitated in human platelets by radioimmunoassay using antisera specific to platelet membranes and purified glycoprotein IIIa. Glycoprotein IIIa and glycoprotein IIb were isolated from washed platelets by Triton X-114 extraction followed by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Radioiodinated glycoprotein IIIa was further purified by affinity chromatography on Lentil lectin-Sepharose 4B. Purified glycoprotein IIb showed little crossreactivity with 125I-labeled glycoprotein IIIa using the anti-platelet membrane or anti-glycoprotein IIIa antisera on a competition inhibition radioimmunoassay. The expression of glycoprotein IIIa epitopes were the same for the purified glycoprotein IIIa and glycoprotein IIIa in Triton X-100 solubilized platelets. A 66 kDa protein derived from glycoprotein IIIa by limited proteolysis of platelet membranes also expressed the same epitopes as intact glycoprotein IIIa. Solubilized platelets contained approximately 16 micrograms of total glycoprotein IIIa antigen per 10(9) cells. The level of glycoprotein IIIa determined by radioimmunoassay in one patient with Glanzmann's thrombasthenia amounted to 6.7% of normal and it was close to the values obtained by other methods.

Aggregation of chymotrypsin-treated thrombasthenic platelets is mediated by fibrinogen binding to glycoproteins IIb and IIIa.

Previous experiments demonstrated that chymotrypsin, but not adenosine diphosphate (ADP), exposed fibrinogen binding sites on platelets from patients with Glanzmann's thrombasthenia. Three of these patients have been reexamined, and previous observations were confirmed. The quantity of iodine 125-labeled glycoprotein IIb (GPIIb) and glycoprotein IIIa (GPIIIa) on the platelets of these patients was considerably less than normal but was detectable by immunoprecipitation, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and autoradiography. The amount of residual GPIIb and GPIIIa as measured by binding studies with radiolabeled monoclonal antibodies was between 3% and 12% of the normal value. Platelet suspensions from these patients did not aggregate with fibrinogen and did not bind 125I-fibrinogen on stimulation with ADP. However, incubation of these platelets with chymotrypsin or pronase resulted in fibrinogen binding and platelet aggregation. Monoclonal antibodies specific for the GPIIb-GPIIIa complex blocked both the fibrinogen binding and the aggregation of enzyme-treated platelets. The treatment of washed platelets of a fourth thrombasthenic patient with ADP or with chymotrypsin failed to result in fibrinogen binding and aggregation. However, the level of GPIIb and GPIIIa on these platelets as measured by a Western blot technique and by monoclonal antibody binding amounted to less than 0.35% to 0.5% of normal values. In conclusion, fibrinogen binding sites exposed on thrombasthenic platelets by chymotrypsin are derived from GPIIb-GPIIIa molecules. Aggregation of chymotrypsin-treated thrombasthenic platelets by fibrinogen appears to represent a sensitive test for detection of functionally active GPIIb-GPIIIa complex on the platelet surface.

Loss of fibrinogen receptors from the platelet surface during simulated extracorporeal circulation.

In vitro recirculation of fresh human heparinized blood in an extracorporeal circuit with a membrane oxygenator decreased fibrinogen-induced platelet aggregation and diminished the number of fibrinogen receptors and glycoprotein IIb/IIIa (GPIIb/GPIIIa) antigenic sites on the platelet surface. In seven experiments, the mean +/- SD Km value for fibrinogen (i.e., molar concentration of fibrinogen required to cause 50% of the maximal rate of aggregation) was 1.58 X 10(-7) mol/L +/- 0.68 X 10(-7) mol/L. After recirculation, this value increased to 3.8 X 10(-7) mol/L +/- 1.94 X 10(-7) mol/L (P less than or equal to 0.025). The maximal aggregation rate of chymotrypsin-treated platelets decreased by 40% after 2 hours of recirculation (P less than or equal to 0.025). The number of fibrinogen receptors on platelets, which were treated with chymotrypsin after a recirculation, decreased from 41,370 +/- 24,000 to 13,230 +/- 10,230/platelet under the same conditions (P less than or equal to 0.025). The number of antigenic sites for monoclonal antibody reacting with GPIIb/GPIIIa complex of adenosine diphosphate-stimulated platelets decreased from 34,200 +/- 5,940 to 19,500 +/- 9,680/platelet after recirculation (P less than or equal to 0.025). Prostaglandin E1 (0.3 mumol/L) in the perfusion circuit preserved the ability of platelets to react with fibrinogen. In conclusion, the loss of fibrinogen receptors from the surface of platelet membranes results from the interaction of platelets with the surfaces of perfusion circuits.

Interaction of platelet factor 4 with human platelets.

Human washed resting platelets bound 125I-labeled platelet factor 4 in a reaction which was saturable and approached equilibrium within 15-30 min. Scatchard plot analysis of the binding isotherms suggested a single class of specific binding sites. Excess of unlabeled protein and low- and high-affinity heparin competed for platelet factor 4 binding sites on the platelet surface and caused a partial displacement of this molecule. Anti-platelet factor 4 Fab fragments caused inhibition of binding of 125I-platelet factor 4 to platelets. Most of the labeled platelet factor 4 which was bound to intact platelets was recovered in the Triton X-100-insoluble cytoskeletal fraction prepared from the same platelets after their stimulation by thrombin. The association with the cytoskeleton was inhibited by anti-platelet factor 4 Fab fragments and by low-affinity heparin. Anti-platelet factor 4 125I-labeled Fab fragments bound to resting platelets, and this binding was greatly increased following platelet stimulation with thrombin. This suggested that endogenously secreted platelet factor 4 also binds to the platelet surface. No significant binding to platelets of 125I-labeled beta-thromboglobulin and 125I-labeled anti-beta-thromboglobulin Fab fragments was observed. Fab fragments of monospecific anti-human platelet factor 4 antibody raised in rabbits inhibited platelet aggregation and secretion induced by low concentrations of thrombin. Fab fragments of anti-beta-thromboglobulin antibody had no inhibitory effect. We suggest that the binding of alpha-granule-derived platelet factor 4 to the specific sites on the surface of platelets may modulate platelet aggregation and secretion induced by low levels of platelet agonists.

Comparison of platelet fibrinogen receptors on intact and proteolytically-treated platelets by use of an anti-glycoprotein IIIa monoclonal antibody (MA 123).

A murine monoclonal antibody (MA 123) was selected by screening 153 supernatants of hybridoma cells secreting anti-human platelet antibodies for their ability to inhibit the fibrinogen-induced aggregation of chymotrypsin-treated platelets. MA 123 inhibited the binding of 125I-fibrinogen to ADP-stimulated intact human platelets and to platelets treated with chymotrypsin or pronase. Moreover, it inhibited the fibrinogen-induced aggregation of these platelet suspensions. The degree of inhibition was similar in each of the three types of platelets tested. The interactions of MA 123 with the 125I-labeled surface components of intact and chymotrypsin-treated platelets were studied by immunoprecipitation using Staphylococcus aureus coated with goat anti-mouse IgG, followed by SDS-polyacrylamide gel electrophoresis and autoradiography. MA 123 precipitated the glycoprotein IIb-glycoprotein IIIa (GPIIb-GPIIIa) complex from the surface of detergent solubilized intact human platelets; and it precipitated GPIIIa from the surface of chymotrypsin-treated platelets. Partially purified GPIIIa was also immunoprecipitated by MA 123. Our data suggest that the exposure of fibrinogen receptors by ADP, chymotrypsin or pronase, is associated with alterations of GPIIIa on the platelet surface.