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Disruption of the blood-brain-barrier (BBB) is important in the pathophysiology of various inflammatory conditions of the central nervous system (CNS), such as multiple sclerosis (MS), in which breakdown of the BBB precedes any clinical or pathological findings. There is some evidence that relapsing-remitting MS attacks may be correlated with certain types of acute stressful episodes. Stress typically activates the hypothalamic-pituitary-adrenal (HPA) axis through the release of corticotropin releasing hormone (CRH), leading to production of glucocorticoids that down regulate immune responses. However, acute stress also has pro-inflammatory effects that appear to be mediated through activation of mast cells. Here we show that acute stress by immobilization increased permeability of rat BBB to intravenous 99Technetium gluceptate (99Tc). This effect was statistically significant in the diencephalon and the cerebellum, while it was absent in the cerebral cortex where there are not mast cells. Immobilization stress also induced activation of mast cells in diencephalon, the site where most mast cells are found in the rat brain. Both BBB permeability and mast cell activation were inhibited by the 'mast cell stabilizer' disodium cromoglycate (cromolyn). These results expand the pathophysiology of mast cells and implicate them in CNS disorders, that may possibly be induced or exacerbated by stress.

We conducted a pilot study to examine patients' understanding of their illness and their expectations for palliative radiotherapy for symptomatic metastases. Participants were asked to complete a survey consisting of seven questions prior to the initial consultation. Demographic details and information on extent of disease were collected. Patients were asked to score their symptom distress using the modified Edmonton Symptom Assessment System. Sixty patients participated in the pilot study between January and April 1999. Their median age was 68 years (range 46-90). The most common primary tumours were lung, prostate and breast. Twenty-one patients (35%) believed that their cancer was curable. Twelve (20%) expected that palliative radiotherapy would cure their advanced cancer and 23 (38%) believed that palliative radiotherapy would prolong their lives. Twenty-one patients (35%) had concerns about the effectiveness of radiation therapy and twenty (33%) had concerns about the side-effects of radiotherapy. Fifty-two (87%) were not familiar with the concept of radiation treatment. Forty-seven patients (78%) reported that they were not given information about the radiation treatment; 51 (85%) were not satisfied with the information that their own doctors had provided regarding radiation treatment prior to the consultation at our clinic. A significant proportion of the patients in this pilot study had misconceptions regarding their illness and unrealistic expectations from palliative radiotherapy. We plan to provide educational pamphlets for use in referring doctors' surgeries and clinics in order to inform patients of the nature, rationale and anticipated benefits and side-effects of palliative radiotherapy.

The use of prosthetic material in severe cases of congenital diaphragmatic hernia is complicated by infection, bowel adhesion, and patch dehiscence. We hypothesized that a bioprosthetic collagen patch would reduce these complications and be remodeled into autogenous tissue over a short period of time. Thirty-two New Zealand White rabbits had two 2 x 2-cm left diaphragmatic defects created. One of these defects was repaired with a collagen bioprosthetic patch (n = 20) and the other with a polytetrafluoroethylene (PTFE) patch (n = 20). Members of a control group (n = 12) had their defects closed primarily. The animals were then placed in either a 6- or 12-week survival cohort. At necrosectomy the repairs were assessed histologically, graded for adhesion formation, and tensiometrically tested. The PTFE patch was noted to have a significantly higher average adhesion grade than the collagen patch. The tensile strength of the two repair methods was statistically equivalent at both time intervals. On histologic examination the collagen patches were surrounded by an increased number of macrophages and fibroblasts. The PTFE patch exhibited no neovascularization or fibroblast deposition at the periphery, but had a much greater surrounding inflammatory response. Thus, there was evidence of early remodeling of the collagen with no increase in the amount of adhesions or loss of strength when compared to the PTFE, while the PTFE patches exhibited a more severe grade of adhesions.

Two-dimensional contrast echocardiography has been shown to enable the evaluation of myocardial perfusion abnormalities. However, its ability to quantify a regional myocardial mass is limited. The goal of this study was to examine the quantitative value of 3-dimensional echocardiography (3DE) in the estimation of myocardial mass at risk, salvaged mass, and residual infarct mass after intravenous injection of contrast. We created acute coronary occlusion, followed by reperfusion in 10 dogs. Three-dimensional echocardiographic data were acquired at the end of each stage, and the perfusion defect mass and dysfunctional mass were measured. The true mass at risk and infarct mass were determined by anatomic methods. The anatomic mass at risk (x) (27.1+/-14.6 g or 23.8%+/-9.7% of the left ventricle [%LV]) correlated well with the 3DE-determined perfusion defect mass (y) during coronary occlusion (y = 0.5x+8.9; r = 0.90; P<.001; mean difference -4.8+/-8.1 g; or y = 0.7x + 6.5; r = 0.83, P<.01; mean difference -0.1+/-5.4 %LV). Good correlation was also found between the anatomic infarct mass (x) (9.3+/-8.1 g or 9.1+/-8.8 %LV) and the 3DE perfusion defect mass after reperfusion (y) (y = 1.2x+1.2; r = 0.93; P<.001; mean difference 2.3+/-4.0 g; or y = 1. 3x, r = 0.98, P <.0001; mean difference 2.7+/-3.7 %LV). The salvaged mass was 13.6 +/-11.0 %LV from anatomic methods and 14.2+/-13.0 %LV by 3DE. To conclude, with the use of intravenous contrast, 3DE could quantify the actual mass at risk during acute ischemia, and in the setting of reperfusion, the residual infarct mass and salvaged mass.

Echocardiographic evaluation for the recognition of intravascular and left atrial appendage thrombus remains a difficult problem. A thrombus-specific ultrasonographic contrast agent has the potential for an alternative approach for their delineation. The aim of this study was to investigate the usefulness of thrombus-specific contrast agent MRX-408A1 for the detection of acute experimentally created intravascular and intracardiac thrombus. In the first study, we created inferior vena cava thrombus in 9 dogs. With the use of fundamental 2-dimensional echocardiography imaging, we recorded images of the inferior vena cava thrombus at baseline (n = 9), with the thrombus-specific contrast agent MRX-408A1 (n = 9), and with nonspecific contrast agent MRX-113 (n = 6). In the second study, we created a left atrial appendage thrombus in 8 dogs. We imaged left atrial appendage thrombus at baseline and during MRX-113 and MRX-408A1 infusion. Thrombus was successfully created in all dogs in study 1 and in 6 of 8 dogs in study 2. MRX-408A1 produced a visually apparent increase in ultrasonographic contrast enhancement of the thrombus in all cases in which thrombus was found on autopsy. In both studies, MRX-408A1 increased the videointensity of the thrombus significantly compared with baseline images and images obtained during MRX-113 infusion. The size of the visually detectable thrombus on the image was also significantly larger during MRX-408A1 infusion than at baseline and during MRX-113 infusion. These data provide in vivo demonstration of the efficacy of a thrombus-specific contrast agent, MRX-408A1, in the detection of acute intravascular and intracardiac thrombus. It has the potential to improve the diagnostic accuracy of ultrasonography for the detection of acute thrombi at various cardiovascular sites in the clinical setting.

The increase in laparoscopic surgery has resulted in an increased need for a safe and reliable method of obtaining minimally invasive operative hemostasis. Because the traditional "open" methods of controlling bleeding (pressure, tying, and suture ligating) are not as easily applied in the laparoscopic arena, a heavy reliance on forms of tissue and vessel coagulation is necessary. To better assess these forms, we compare monopolar, bipolar, and ultrasound energy, in addition to laser energy used in a novel application. In the first part, 20 rabbit mesenteric arteries that measured 1 to 1.5 mm in diameter were coagulated using each of the technologies. We measured the time to coagulation, the efficacy of hemostasis, lateral tissue damage, and local tissue temperature of the vessels when exposed. Part 2 consisted of a survival study using 12 New Zealand white rabbits. In each of these two groups splenectomies were performed. A laser-heated forceps was compared to a monopolar electrosurgery device for the speed of the operation, blood loss, and adhesion grade at necrosectomy. In addition, the speed to cauterization of the iliac vessels and the amount of tissue damage was measured. These vessels were also examined for the extent of microscopic damage. Bipolar electrosurgery was much slower than the other modalities, while monopolar electrosurgery caused significantly more tissue damage and elevation in lateral tissue temperature. The ultrasound technology and the laser-heated forceps were equally safe and efficacious instruments. There was no significant difference in the ability of the laser-heated forceps or the monopolar cautery to perform the splenectomy safely. However, the forceps cauterized the iliac vessels faster and with less lateral thermal injury than the ultrasound device. Although each instrument has its place in the surgical armamentarium, the ultrasound technology appears to be the safest and most efficacious commercially available device for obtaining hemostasis. The laser, as it is applied in this setting, was also highly effective, but still a prototype device.

Background: Bloodwarmers, mandatory for use in trauma resuscitation, are currently limited to a maximum temperature of 42 degrees C by the American Association of Blood Banks. Using newly available inline microwave bloodwarming technology, we sought to identify the maximal temperature to which blood may be safely heated., Methods: Using an inline microwave bloodwarmer, we warmed refrigerated packed red blood cells to settings ranging from "Off" to 60 degrees C. We evaluated heated blood for changes in red cell structure and function by measuring hemoglobin/hematocrit, potassium, lactate dehydrogenase, plasma hemoglobin, blood smear, osmotic fragility, PO2, giving 50% O2 saturation, and hemoglobin electrophoresis., Results: Measures of hemolysis showed no increase above control until temperatures of 51 to 53 degrees C were achieved (p < 0.05). Red cell size remained unaffected until temperatures of 53 degrees C were achieved (p < 0.05). Osmotic fragility was not elevated until 60 degrees C (p < 0.05). PO2 giving 50% O2 saturation was low for all samples. Hemoglobin electrophoresis remained unchanged at all temperature settings., Conclusion: An inline microwave bloodwarmer may be used to heat blood safely to 49 degrees C. Blood warmed to this temperature may significantly increase the amount of heat returned to the hypothermic trauma patient.

Background: Current induced in a guidewire during papillotomy poses a danger of injury to the bile duct. We measured currents induced in three commercially available guidewires and a prototype fiberglass wire during simulated sphincterotomy under standard and nonstandard conditions., Methods: Blended current at 55 W was applied to a double-lumen papillotome grounded through a 1000 omega resistor. For extreme conditions, power was increased to 70 W using a single-lumen papillotome. Fault conditions were created with a break in the insulation at the distal end of each wire. Guidewire-induced current was measured, and safety calculations performed for adherence to accepted standards for electrosurgical devices., Results: Induced current was within safety limits for all wires tested under standard conditions. With insulation faults, one of the commercially available wires was unsafe. Under extreme conditions, with or without faults, the three commercial wires produced currents ranging from 9% to 225% above acceptable levels, while only the prototype wire remained safe., Conclusions: Most guidewires contain metal cores that function as capacitors. Because its core is primarily fiberglass, the prototype wire generates less induced current under nonstandard conditions, thus achieving a greater margin of safety during wire-guided sphincterotomy.

Growing interest in the endoscopic treatment of vesicoureteral reflux and urinary incontinence has led to the development of safe reliable techniques that use an injectable bulking agent. A variety of injectable materials has been studied, such as polytetrafluoroethylene, fat and bovine collagen. We evaluated autologous collagen extracted from the dermis of skin for potential use in the urinary tract. Therefore, an animal model was developed to study the biological behavior of autologous collagen within the bladder. Collagen was extracted from the skin of rabbits and radiolabeled with 125iodine. An aliquot of radiolabeled autologous collagen was injected submucosally in the bladder. The animals were monitored weekly under a gamma camera. The decay of the radiolabeled collagen was recorded during 50 days. The animals were then sacrificed and the bladder wall at the site of injection was studied histologically and on electron microscopy. Decay of the injected collagen within the urinary tract was similar to control material, indicative of good stability within the bladder. A mild inflammatory response with fibroblastic and vascular invasion of the collagen implant was observed. These preliminary data suggest that autologous collagen injected endoscopically can provide a safe reliable bulking material that could be used to treat urinary incontinence and lower grades of vesicoureteral reflux in children.

1. Cryosurgical ablation of the prostate is an attempt to use the proved cytodestructive abilities of cryosurgery in combination with the guidance of transrectal ultrasound to provide local disease control with less morbidity and a quicker recovery period. 2. Cryosurgical ablation of the prostate begins as a same day admission. Patients are out of bed and eating as tolerated that evening. They are generally discharged the following day if able to manage the suprapubic tube. 3. Though the recovery period is generally a quick one, there exist many idiosyncrasies to this recovery which make careful interaction between the physician, nurse, and patient critical.

Membrane glycoprotein alpha IIb beta 3 on platelets plays a pivotal role in hemostasis by mediating RGD-(arginine-glycine-aspartic acid)-dependent platelet adhesion and aggregation. Antagonists of alpha IIb beta 3 ligand binding function, such as antibodies, snake venom peptides, or synthetic RGD-containing peptides can completely inhibit platelet aggregation in vitro and cause significant prolongation of bleeding times when injected into experimental animals. The in vitro and in vivo properties of an alpha IIb beta 3 specific RGD-containing peptide 2G (G(Pen)GHRGDLRCA) were compared to two non-specific RGD-containing peptides 1N (G(Pen)GRGDTPCA) and 2H (GRGDSPDG). All three peptides have similar IC50 values in human platelet aggregation (14-22 microM) and ELISA-based alpha IIb beta 3 receptor assays (0.2-0.3 microM) but show different inhibitory activity (IC50 values) in the alpha v beta 5 (2G = 10 microM; 1N = 0.06 microM; 2H = 0.05 microM) and alpha 5 beta 1 receptor assays (2G = 8.3 microM; 1N = 0.06 microM; 2H = 0.04). The alpha IIb beta 3 specific peptide 2G had no effect on monolayers of human saphenous vein endothelial cells while 1N and 2H caused many cells to detach and contract. Peptides 2G and 1N inhibited ADP-stimulated ex vivo platelet aggregation in dogs in a dose dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Wernicke's encephalopathy is a serious neurological manifestation of vitamin B1 deficiency. We report a case occurring secondary to hyperemesis gravidarum.

Previous studies have established the feasibility of combining tissue heat generated by radio-frequency (RF) current and mechanical pressure to manage problems of percutaneous transluminal angioplasty (PTA) that are thought to cause postangioplasty restenosis (PARS). In the current in vitro study of normal and atherosclerotic human aortic layers (intima-media and media-adventitia) separated artificially, the purposes were to identify a dose-response relationship between the total RF energy delivered and the resultant weld strength between vascular tissues and to study the histologic correlates. Twenty-eight control and 100 experimental specimens were evaluated. The mean weld strength for all specimens with no RF current (at 0 J) was 4.1 g +/- 2.0; at 100 J, 5.9 g +/- 2.8; at 200 J, 28.5 g +/- 3.3; at 300 J, 50.0 g +/- 5.5; and at 500 J, 82.0 g +/- 8.2. Inspection of treated specimens revealed vascular molding (depression in the surface corresponding in dimensions to those of the electrode gap in the treatment chamber). Histologic examination revealed necrosis in the region underlying the electrode gap, a hypocellular fusion zone, indistinct boundaries between welded specimen parts, and transition zones to normal histologic characteristics at either end of each specimen. RF energy combined with mechanical pressure produces dose-dependent thermal welds in artificially dissected vascular tissues, molding of vascular tissue, and cellular destruction in the media. These findings may have clinical application in the management or prevention of all forms of PARS in humans and in the treatment of spontaneous aortic dissection.

Post-angioplasty restenosis (PARS) in atherosclerotic lesions of medium and small arteries occurs in about one-third of cases in the first year following percutaneous transluminal angioplasty (PTA) (early PARS). PARS includes acute spasm, dissection with reclosure, elastic recoil, fibrocellular proliferative response, and progressive atheromatous disease. Fibrocellular proliferation (possibly initiated by platelet derived growth factor) is felt to be culpable in many cases of early PARS (months). Pharmacologic regimens, stents, and thermal welding of the intimal-medial cracks of PTA are among the interventions being developed to deal with PARS. Radiofrequency (RF) current as a source of thermal energy may be useful in combination with balloon angioplasty to reduce PARS. Ideally, this combination would (1) weld intimal-medial cracks of PTA; (2) mold plaque and normal vessel to increase lumen diameters without creating intimal-medial cracks; and (3) destroy medial smooth muscle cells and multipotential cells (cellular substrate of PARS). Canine in vivo studies have established the feasibility of RF-mediated vascular tissue welding. Human aortic specimens (N = 28) were manually dissected into intima-media and media-adventitia layers. Bipolar RF energy (650 KHz, total 300 J) and mechanical pressure (1 atm) (experimental group, N = 24) or mechanical pressure alone (control group, N = 4) were applied to the reapposed specimen layers in a special chamber. The chamber was modified with a bipolar electrode designed to reproduce that planned for an RF balloon angioplasty catheter. Welding was demonstrated in normal and atherosclerotic treated specimens (23/24 or 96%) but not controls (0/4).(ABSTRACT TRUNCATED AT 250 WORDS)

The interaction of 111Indium-labeled platelets, and other blood components with the luminal surface of polydimethylsiloxane (PDMS) and low-density polyethylene (LDPE) was determined using an ex vivo arteriovenous shunt in the baboon. Both PDMS and LDPE showed little platelet accumulation at either high (200 cc/min) flow rates. PDMS accumulated more platelets at low than at high flow. When the surfaces of PDMS and LDPE were examined under scanning electron microscopy after 2.5 h of flow in the shunt circuit, red and white blood cells were attached. Platelets appeared to be confined to patchy areas covered by a fibrinlike network. The low platelet reactivity of LDPE and PDMS suggests their potential use as coatings for conventional, more platelet reactive vascular graft materials.

Previous studies have demonstrated the importance of employing prosthetic material with minimal thrombogenicity. However, the role of different suture materials in early thrombotic events on prosthetic materials has not been examined. Experiments were designed to analyze the effects of suture on platelet graft interaction using an in vivo baboon hemocompatability screen. 111Indium labeled, autologous platelet deposition was determined on expanded polytetrafluoroethylene (ePTFE) containing suture lines of polypropylene (Prolene), polybutester (Novafil), and ePTFE (Gore-Tex). A significant increase in platelet deposition was noted not only at the suture line, but proximal and distal to it as well. The results were different for each of the sutures employed and suggest that the suture line may influence early platelet deposition in the perianastomotic region, not only at the suture line, but proximally and distally as well.

Low molecular weight dextran (LMD) has recently been shown in a randomized, multicenter trial to improve early patency in difficult lower extremity vascular bypass. The question remained as to whether this effect was due to plasma volume expansion by LMD or to its effects on platelets and coagulation. To analyze this we have studied the effects of LMD on platelet-graft interactions using an ex vivo baboon shunt. Indium 111-labeled autologous platelet deposition on expanded polytetrafluoroethylene and knitted Dacron grafts was monitored at a flow rate of 25 ml/min for 21/2 hours. LMD was given by intravenous bolus at a dose of 5 ml/kg and was followed by a continuous infusion of 10 ml/hr. Flow through the shunt was started after the initial dextran bolus. Control studies were performed in a similar manner without dextran. An additional series of experiments was performed with a 5 to 10 ml/kg bolus of 5% human serum albumin to analyze the contribution of plasma volume expansion to platelet deposition in this model. The results revealed a significant (p less than 0.05) reduction in platelet deposition on both graft materials with the LMD infusion. No difference was seen between the control group and the albumin group. These studies provide direct in vivo evidence of the antiplatelet effect of LMD.

Dacron (polyester fiber), a stimulus to platelet aggregation in vitro, accumulates platelets to a greater extent in vivo than autogenous artery, polytetrafluoroethylene (PTFE) or human umbilical vein (HUV). We conducted a series of experiments using the ex vivo shunt in the baboon to determine whether or not systemic activation of platelet function was produced by a Dacron graft. Two 5 centimeter segments of 4 millimeter internal diameter graft materials were placed in series in the ex vivo shunt perfused at 25 milliliters per minute flow rate for two and one-half hours. Deposition of autologous Indium 111 labeled platelets was monitored. The ex vivo shunt procedures were divided into two groups, both with PTFE as the proximal graft: one with a distal Dacron graft (n = 21), the second with PTFE or HUV distally (n = 17). In this study, an increase in platelet deposition on the proximal PTFE graft represents systemic platelet activation caused by the distal graft. Increased platelet deposition on PTFE was noted at all time points in the presence of a Dacron graft (p less than 0.05). This property of Dacron has important clinical implications, potentially accelerating the progression of vascular disease, increasing the failure rate of composite grafts and subsequent arterial reconstruction.

Assessed moral reasoning of 20 male addict patients and 17 nonprofessional male hospital employees by Kohlberg's methods. The mean level of moral reasoning of the drug addict group (2.97) was not found to differ significantly from that of the nonaddict comparison group (2.88). Furthermore, moral reasoning in addicts was not found to be related significantly to a number of background and personality characteristics. The findings, therefore, indicated that moral reasoning and moral behavior are not related significantly in drug addicts. It was concluded that the deviant behavior of this group is more likely the result of a deficiency in ego controls.

We compared the in vivo platelet reactivity of two commonly used clinical grafts, Dacron and expanded polytetrafluoroethylene (PTFE), with that of a control autogenous artery graft and assessed whether platelet reactivity was modified by the platelet-antiaggregating agent prostacyclin (PGI2) (epoprostenol). Grafts were randomly placed into the carotid arteries of 21 baboons. Platelets labeled with indium 111 were infused within one hour after implantation graft for gamma camera scanning of platelet uptake. The accumulation of platelets on Dacron grafts began almost immediately after injection and reached a peak after one to two hours. The PTFE and control autogenous artery grafts accumulated comparable small amounts of platelets. Prostacyclin was then infused in a second series of baboons with Dacron grafts, at a rate of 150 to 200 ng/kg/min. It prevented the usual platelet uptake when administered concomitant with graft implantation and reduced previously established platelet activity.

Rates of cerebral perfusion were obtained from measurements of the disappearance (wash-out) of oxygen-15 after in situ tissue activation with 45-million-volt x-rays. In an anesthetized cat, typical values were 90 milliliters per minute per 100 grams of tissue, with 55 percent wash-out. In a specific radiotherapy patient, the value was 65 milliliters per minute per 100 grams of tissue, with 63 percent wash-out of oxygen-15 through incorporation into tissue water.

Advances in venous reconstruction have been limited by inherent venous thrombogenicity and the absence of a suitable prosthetic material for use in the venous system. We have designed an in vivo experimental model to evaluate early blood-material interactions within the venous system and to quantitate drug efficacy in the alteration of platelet function and fibrin deposition in the baboon. An 8F catheter was placed percutaneously in the femoral vein of an adult male baboon. Indium 111-labeled autogenous platelets or iodine 125-labeled human fibrinogen was infused before the introduction, into the inferior vena cava, of a linear array of 5 x 15 mm alternating Dacron and polytetrafluoroethylene samples attached to a benzalkonium-heparin-treated guide wire. At 60 or 120 minutes the samples were removed and a 1 ml aliquot of blood was drawn. The materials and blood samples were counted in a gamma well counter, and the material counts were normalized to the circulating label present in the 1 ml blood sample. The experiment was repeated after pretreatment with heparin, aspirin, or dextran. Whole blood clotting times and bleeding times were monitored. The results showed decreased platelet and fibrin deposition on polytetrafluoroethylene when compared with Dacron in the venous system. Aspirin, heparin, and dextran were all found to decrease platelet and fibrin deposition onto intravenously placed graft material samples (p less than 0.05, Student's t test). The data confirm the ability of the model to evaluate quantitatively anticoagulants, antiplatelet agents, and prospective graft materials for use in venous reconstructions.

19 alcoholics and 20 addicts were selected from the detoxified inpatient population of a VA hospital. 17 socioeconomically matched controls were drawn from the nonprofessional staff. Kohlberg's Moral Maturity scores were not significantly different for the three groups. However, the content variables involved in choosing between the value of life and law differentiated these groups. The value of reporting both structure and content was examined.

Six adult male rhesus monkeys (Macaca mulatta) were anesthetized using a combination of acepromazine maleate and ketamine hydrochloride administered by intramuscular injection. This combination produced a smooth induction to anesthesia requiring less than 5 minutes. The average duration of anesthesia was slightly less than 1 hour and was safely prolonged with additional doses of ketamine. The depth of anesthesia was sufficient for minor surgical procedures and for precise radiological studies. No deleterious side effects were noted, and animals recovered completely in a short time.

The activated platelet is a potential target for the localization of thrombi in vivo since, after stimulation and secretion of granule contents, activated platelets are concentrated at sites of blood clot formation. In this study, we used antibodies specific for a membrane protein of activated platelets to detect experimental thrombi in an animal model. PADGEM (platelet activation-dependent granule-external membrane protein), a platelet alpha-granule membrane protein, is translocated to the plasma membrane during platelet activation and granule secretion. Since PADGEM is internal in unstimulated platelets, polyclonal anti-PADGEM and monoclonal KC4 antibodies do not bind to circulating resting platelets but do interact with activated platelets. Dacron graft material incubated with radiolabeled KC4 or anti-PADGEM antibodies in the presence of thrombin-activated platelet-rich plasma bound most of the antibody. Imaging experiments with 123I-labeled anti-PADGEM in baboons with an external arterial-venous Dacron shunt revealed rapid uptake in the thrombus induced by the Dacron graft; control experiments with 123I-labeled nonimmune IgG exhibited minimal uptake. Deep venous thrombi, formed by using percutaneous balloon catheters to stop blood flow in the femoral vein of baboons, were visualized with 123I-labeled anti-PADGEM. Thrombi were discernible against blood pool background activity without subtraction techniques within 1 hr. No target enhancement was seen with 123I-labeled nonimmune IgG. 123I-labeled anti-PADGEM cleared the blood pool with an initial half-disappearance time of 6 min and did not interfere with hemostasis. These results indicate that radioimmunoscintigraphy with anti-PADGEM antibodies can visualize thrombi in baboon models and is a promising technique for clinical thrombus detection in humans.

The tin(II) colloid is highly surface active and adheres strongly to glass surfaces. Treating glass with 5% (v/v) dichlorodimethylsilane in toluene causes a significant reduction in the adhesion of the colloid.

Tenotomy of the medial and superior recti resulted in decreased blood flow to only the superior quadrant of the unit iris, ciliary body with processes (ICBCP). Blood flow to the medial, lateral, and inferior quadrants of the ICBCP was maintained. These data support the contention that tenotomy initiates a compensatory increase in medial quadrant blood flow, probably via the medial long posterior ciliary artery. The superior quadrant appears to be the least protected from ischemia immediately following recti tenotomy.