Inhibition of human platelet function in vivo with a monoclonal antibody. With observations on the newly dead as experimental subjects

The F(ab')2 fragment of a monoclonal antibody to the platelet glycoprotein IIb/IIIa receptor (7E3) is a potent inhibitor of both in-vitro platelet aggregation and in-vivo platelet thrombus formation in animal studies. As a first step in assessing the potential of 7E3-F(ab')2 as an antithrombotic agent for use in humans, we administered 7E3-F(ab')2 intravenously at increasing doses to a person who had just died and was being maintained on a respirator (neomort). At 0.1 and at 0.2 mg/kg body weight, 74% and 92% of the glycoprotein IIb/IIIa receptors were blocked, respectively; adenosine-diphosphate-induced platelet aggregation was inhibited by 84% and 100% at these same doses. Platelet glycoprotein Ib function remained intact, even at 0.6 mg/kg. Acute hemodynamic or hemorrhagic toxicity was not noted. This antibody fragment, a potent, immediate-acting inhibitor of platelet aggregation, may be of benefit in vaso-occlusive and thromboembolic disorders.     

Thromboerythrocytes. In vitro studies of a potential autologous, semi-artificial alternative to platelet transfusions.

In an attempt to overcome the limitations and drawbacks of using fresh platelets for transfusion therapy of thrombocytopenic patients, we have performed in vitro experiments on an autologous, semi-artificial alternative to platelet transfusions. Based on our previous studies of the interactions of unactivated and activated platelets with beads coated with peptides of various lengths, all of which contained the arginine-glycine-aspartic acid (RGD) cell recognition sequence, the peptide Ac-CGGRGDF-NH2 was chosen for covalent coupling to erythrocytes. A heterobifunctional crosslinking reagent (N-maleimido-6-aminocaproyl ester of 1-hydroxy-2-nitrobenzene-4-sulfonic acid) was used to crosslink via the peptide's free sulfhydryl group and the erythrocyte's surface amino groups. Approximately 0.5-1.5 x 10(6) peptide molecules bound per erythrocyte after 2 h of incubation, and most of the peptides appeared to crosslink to glycophorin A. The resulting cells, termed thromboerythrocytes, interacted selectively with activated platelets to form mixed aggregates. Studies with fluid phase RGD peptides and monoclonal antibodies indicated that the RGD peptides on the thromboerythrocytes interacted with the GPIIb/IIIa receptors on activated platelets. Thromboerythrocytes could also bind to platelets adherent to collagen. There was minimal erythrocyte hemolysis during the formation of thromboerythrocytes and studies of thromboerythrocyte osmotic fragility and cellular deformability showed no significant changes from control erythrocytes. Whereas there is a 20:1 ratio of erythrocytes to platelets in the circulation of normal individuals, the erythrocytes from as little as 50 ml of blood could be transformed into the equivalent of 2 U of platelets by numbers (equivalent to 18 U of platelets by mass), and reinfused into the same individual within several hours. These data encourage us to proceed to in vivo studies to assess the hemostatic efficacy of thromboerythrocytes in thrombocytopenic animals.     

Prophylactic Chemoradiation of Inguinofemoral Lymph Nodes in Patients with Locally Extensive Vulvar Cancer

Objective.Primary surgical resection of locally advanced squamous cancer of the vulva may compromise the integrity of important midline structures such as the anus, clitoris, urethra, and vagina. Chemoradiation (synchronous radiation and cytotoxic chemotherapy) has been used as alternative initial treatment which may serve as definitive management for some patients, or may reduce the scope and functional sequelae of subsequent surgery in others. Inguinofemoral node dissection is associated with substantial risk of both acute and late morbidity, prompting consideration of elective inclusion of groin nodes within the irradiated volume and deletion of subsequent groin surgery. Concern that disease relapse in the groins is potentially fatal suggested the prudence of formal outcome assessment of our recent experience with prophylactic treatment of clinically uninvolved groin nodes in the context of concurrent chemoradiation for locally advanced primary vulvar cancer.Methods.A review was conducted of 23 previously untreated patients with locally advanced squamous cancer of the vulva (2 T₂, 20 T₃, 1 T₄) and clinically uninvolved groin nodes (1969 FIGO stages 14 N₀, 4 N₁, and 5 N₂with negative node biopsies) who were treated since 1987 with chemoradiation administered to a volume electively including bilateral inguinofemoral nodes. These patients did not undergo subsequent groin surgery.Results.With follow-up from 6 to 98 months (mean, 45.3 months; median, 42 months), no patient has failed in the prophylactically irradiated inguinofemoral nodes. No patient has developed lymphedema, vascular insufficiency, or neurological injury in a lower extremity, and no patient has experienced aseptic necrosis of a femur.Conclusions.Elective irradiation of the groin nodes in the context of initial chemoradiation for locally advanced vulvar cancer is an effective therapy associated with acceptable acute toxicity and minimal late sequelae. It constitutes a sensible alternative to groin dissection in this patient population.     

Hereditary dysautonomias: current knowledge and collaborations for the future

The hereditary dysautonomias (H-Dys) are a large group of disorders that affect the autonomic nervous system. Research in the field of H-Dys is very challenging, because the disorders involve interdisciplinary, integrative, and “mind-body” connections. Recently, medical scientists, NIH/NINDS representatives, and several patient support groups gathered for the first time in order to discuss recent findings and future directions in the H-Dys field. The H-Dys workshop was instrumental in promoting interactions between basic science and clinical investigators. It also allowed attendees to have an opportunity to meet each other, understand the similarities between the various forms of dysautonomia, and experience the unique perspective offered by patients and their families. Future advances in H-Dys research will depend on a novel multi-system approach by investigators from different medical disciplines, and it is hoped that towards a common goal, novel “bench-to-bedside” therapeutics will be developed to improve the lives of, or even cure, patients suffering from dysautonomic syndromes. Received: 17 March 2003, Accepted: 16 April 2003 Correspondence to Dr. S. A. Slaugenhaupt     

Intergeneric behavioral differences among methamphetamine treated mice

Methamphetamine sulfate was administered in acute and chronic experiments, either at constant or increasing doses, to mouse-like rodents belonging to various genera and strains; the behavioral effects arising in a pseudo-natural habitat are described. The animals studied were Onychomys leucogaster, Peromyscus maniculatus Bairdii, Microtus ochrogaster and four Mus strains, Mus musculus ICR, Mus musculus Mo., Mus musculus C57BL/6J, and Mus musculus CF-1. Aggression, grooming, digging, contactual, sexual, sleeping, ingestive, exploratory and stereotypic behaviors were quantitated. Both similarities and differences in the behavioral responses to methamphetamine of the various mice types were noted. These responses are discussed as to their modification by tolerance or increasing doses. Certain neurological and behavioral aberrations due to methamphetamine were noted and correllations with the parameters of mice neurochemistry established in these laboratories are presented.Supported in part by the Research Grant No. 1-RO1 NB 06455 and the Training Grant ST 1 GM77 from the National Institutes of Health, and by the Illinois Mental Health Grant No. 17-176.