Concomitant Cytomegalovirus Viraemia in Multisystem Inflammatory Syndrome in Adults (MIS-A) following COVID-19.

Multisystem inflammatory syndrome in adults (MIS-A) is recognised as an infrequent complication of coronavirus disease 2019 (COVID-19). This syndrome occurs following COVID-19 infection in some individuals and is characterised by inflammation of multiple organ systems, such as the heart, liver, bowel, and lymph nodes. Cytomegalovirus (CMV) viraemia is associated primarily with immunosuppression. In COVID-19 patients, it has been reported in severe and critical cases. We present a case of an adult patient diagnosed with MIS-A and concomitant CMV viraemia.

A Man in His Forties with Recurrent Cat-Scratch Disease.

Cat-scratch disease (CSD) is a self-limited zoonotic infection transmitted by felines caused by the Gram-negative bacillus Bartonella henselae. It usually presents with lymphadenopathy and constitutional symptoms that resolve within eight weeks, with, or without antibiotic treatment. The diagnosis is made by serology, molecular diagnosis in a biopsy, or a positive culture. The recurrence or reactivation of B. henselae has rarely been reported. We present the case of a 45-year-old man with a history of CSD two years before who presented to the clinic with groin lymphadenopathy. The patient had a history of close contact with felines though no known risk exposure was reported. The diagnosis was made with a positive serology suggestive of recent infection along with histopathological changes suggestive of CSD. Subsequently, azithromycin was administered with complete resolution of symptoms.

Hypermucoviscous Klebsiella pneumoniae invasive syndrome in a patient with diabetes without liver abscess.

Klebsiella pneumoniae is part of the human gastrointestinal microbiota. It is also a well-known cause of community and nosocomial infections, involving mainly the lung and urinary tract. An invasive syndrome with liver abscess due to a new hypervirulent strain of K. pneumoniae was recently described. Several cases have been reported, mainly in Asia. Here, we show a case of a patient with an extrahepatic involvement affecting the lung and prostate.

Secondary immune thrombocytopenia supposedly attributable to COVID-19 vaccination.

Immune thrombocytopenia (ITP) has been widely reported as a complication of SARS-CoV-2 infection, but to our knowledge, there have been no reports on the association of the COVID-19 vaccine with thrombocytopenia. Here, we report a case of secondary ITP in a patient who was recently immunised with the messenger RNA COVID-19 vaccine BNT162b2 (Pfizer-BioNTech).

Rhabdomyolysis as an initial presentation in a patient diagnosed with COVID-19.

The presence of rhabdomyolysis secondary to multiple infections has been reported, predominantly viral, but also bacterial and fungal. It is well known that COVID-19 can present a wide variety of complications during the course of infection; however, the presence of rhabdomyolysis as an initial condition has not been reported so far. We report a case of rhabdomyolysis as an initial presentation in a patient diagnosed with SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) infection.

Pulmonary coinfection by Pneumocystis jirovecii and Cryptococcus species in a patient with undiagnosed advanced HIV.

Pneumocystis jirovecii is a common cause of pneumonia in patients with advanced HIV. In a lot of cases, there is a concomitant pulmonary infection. Cryptococcosis presents as a common complication for people with advanced HIV. However, it usually presents as meningitis rather than pneumonia. We present a case of a patient with coinfection by P. jirovecii and Cryptococcus spp without neurological involvement and a single nodular pulmonary lesion.

Fibrinolytic Activity of Circulating Microvesicles Is Associated with Progression of Breast Cancer.

The fibrinolytic system plays an important role in breast cancer, favoring progression through extracellular-matrix degradation, angiogenesis, apoptosis and cellular proliferation. The expression of urokinase-type plasminogen activator (uPA) in breast cancer tissue is widely recognized as an unfavorable prognostic factor. However, fibrinolytic activity associated with uPA cannot be reliably measured in the blood because of the rapid inhibition of uPA by plasminogen activator inhibitor-1 (PAI-1). By contrast, circulating microvesicles (Mvs) in peripheral blood protect bound enzymes from inhibition. Mvs are extracellular vesicles, released from various types of cells, and their size fluctuates between 100 and 1,000 nm. Mvs carry DNA, RNA, miRNA, and proteins, thereby serving as a source of horizontal communication between cells. We investigated whether fibrinolytic activity on circulating Mvs reflects breast cancer progression. The study population consisted of 13 patients with breast cancer and 13 healthy women. The cancer patients included 4 patients in remission, 3 patients with locally advanced cancer, and 6 with metastatic disease. Mvs were isolated from peripheral blood, quantified by a protein concentration method, and their fibrinolytic potential was measured by their capacity to generate plasmin. Although the quantity of Mvs found in patients with cancer and healthy individuals was similar, plasmin generated on Mvs was twice the amount in patients with metastasis than in healthy women (P < 0.05), underlying the value of this distinctive parameter. The data suggest that in breast cancer patients, higher fibrinolytic activity of circulating Mvs could be related to progression and metastasis of breast cancer.

Posición prono en pacientes con síndrome de insuficiencia respiratoria progresiva aguda por COVID-19 / Prone position in patients with acute respiratory failure syndrome due to COVID-19 / Posição prona em pacientes com síndrome da insuficiência respiratória aguda devido ao COVID-19

Resumen: Aproximadamente hasta 5% de los pacientes afectados por la infección por SARS-CoV-2 (COVID-19) requieren estancia en la Unidad de Cuidados Intensivos. De ellos, hasta 71% presentarán Síndrome de Insuficiencia Respiratoria Progresiva Aguda (SIRPA). Colocar a los pacientes en posición prono es una técnica que ha demostrado resultados favorables en aquéllos con hipoxemia refractaria por SIRPA grave. Las Guías Americanas y Europeas actuales del manejo del COVID-19 recomiendan posición prono para mejorar la hipoxemia con resultados variables. Ésta es una técnica de bajo costo que podría mejorar el pronóstico de estos pacientes. Presentamos cinco pacientes con resultados variables en posición prono y concluimos que, al menos en esta primera muestra, hay mejoría de todos en la oxigenación, así como en la imagen radiográfica, lo cual no necesariamente se correlaciona con una mejoría global del paciente.

Abstract: Approximately, up to 5% of the patients infected with SARS-CoV-2 (COVID-19) need to be treated in the Critical Care Unit. Of all these patients, up to 71% will develop Acute Respiratory Distress Syndrome (ARDS). The technique of placing the patients in prone position has had good results in patients with refractory hypoxemia secondary to severe ARDS. The American and European guidelines recommend the use of prone position to improve sever hypoxemia of COVID-19 patients. It is a low cost technique that could improve the outcome in this patients. We present the results of 5 of our first patients with COVID-19 using prone position concluding that at least, in this first sample, there is a good response with improvement of hypoxemia as well as improvement in the chest X-ray images but we cannot conclude if it has an impact in the outcome of the patient, defined as survival or days in mechanical ventilation.

Resumo: Aproximadamente 5% dos pacientes afetados pela infecção por SARS-CoV-2 (COVID-19) necessitam de uma internação na Unidade de Terapia Intensiva. Desse modo, até 71% apresentarão Síndrome da Insuficiência Respiratória Progressiva Aguda (SIRPA). A colocação de pacientes em decúbito ventral é uma técnica que demonstrou resultados favoráveis em pacientes com hipoxemia refratária devido à SIRPA grave. As diretrizes americanas e européias atuais para o manejo do COVID-19 recomendam uma posição propensa a melhorar a hipoxemia com resultados variáveis. É uma técnica de baixo custo que poderia melhorar o prognóstico desses pacientes. Apresentamos 5 pacientes com resultados variáveis em decúbito ventral e concluímos que, pelo menos nessa primeira amostra, há uma melhora na oxigenação e na imagem radiográfica, que não necessariamente se correlaciona com uma melhora geral no paciente.

Osteomielitis secundaria a Pasteurella canis / Osteomyelitis due to Pasteurella canis

Resumen Se comunica el caso de una paciente que sufrió mordedura de perro. Solicitó atención médica inmediatamente en donde realizaron asepsia y antisepsia de la herida para posteriormente tratar la lesión. A las 12 horas la paciente comenzó a mostrar cambios de la coloración, aumento de temperatura, volumen y dolor de severa intensidad, por lo que acudió a nuestro hospital para valoración. Se tomaron cultivos y se realizó resonancia magnética, que mostró datos compatibles con infección de tejidos blandos y osteomielitis. En los cultivos se aisló Pasteurella canis. Se dio tratamiento con antibióticos orales con lo que se logró un desenlace favorable. El género Pasteurella lo constituyen cocobacilos gramnegativos, inmóviles, anaerobios facultativos. La cepa más aislada es P. canis posterior a mordeduras de perro y P. multocida y P. septicum en mordeduras de gato. La manifestación más frecuente es celulitis en el sitio de mordedura o arañazo. El diagnóstico se establece mediante métodos microbiológicos. El tratamiento de elección es la penicilina.

Abstract This paper reports a case of osteomyelitis due to Pasteurella canis after a dog bite. The patient requested medical care immediately after the bite, there were performed asepsis and antisepsis of the wound to later close the injury. After 12 hours, the patient's wound started changing colour with increase in temperature, volume and severe pain, so patient went to our hospital for evaluation. Cultures were taken, and magnetic resonance imaging showed images related to soft tissue infection and osteomyelitis. In cultures, Pasteurella canis was isolated. Treatment was given with oral antibiotics, achieving a favourable outcome. The genus Pasteurella are gram-negative, immobile, anaerobic facultative coccobacilli. The most isolated strain is P. canis after dog bites, and P. multocida and P. septicum in cat bites. The most frequent manifestation is cellulitis at the site of a bite or scratch. The diagnosis is made by microbiological methods. The treatment of choice is penicillin.

Comparación del rendimiento diagnóstico clínico versus la prueba rápida durante dos temporadas de influenza / Comparison of clinical diagnostic performance versus the rapid test during two seasons of influenza

Resumen Introducción Una reflexión de la pandemia de influenza en 2009 es la prioridad de la prescripción temprana de los antivirales, previniendo el uso injustificado de antibióticos. Objetivo: Describir la sintomatología que se asocia más al diagnóstico definitivo de influenza y comparar el rendimiento del diagnóstico clínico contra el diagnóstico arrojado por la prueba rápida. Material y métodos Estudio retrospectivo, transversal, descriptivo y analítico. Se incluyeron pacientes con diagnóstico presuntivo de influenza admitidos en el Servicio de Urgencias del Hospital Español de México en dos temporadas consecutivas que van de octubre de 2016 a marzo de 2017 y de octubre de 2017 a marzo de 2018. Se formaron dos grupos: pacientes con PCR positiva (grupo A) y pacientes con PCR negativa (grupo B). Resultados Se obtuvo un total de 857 pacientes con diagnóstico presuntivo clínico de influenza, de los cuales 537 se confirmaron con influenza por PCR (grupo A) y 320 fueron negativos para dicha prueba (grupo B). El síndrome conformado por tos, fiebre, rinorrea y artralgias tiene una especificidad de 92.2% en comparación con la prueba rápida de 99.1%. Conclusiones El síndrome caracterizado por tos, fiebre, rinorrea, artralgias presentes durante los meses invernales tiene una alta especificidad para infección por el virus de la influenza.

Abstract Introduction One of the reflections of the influenza pandemic in 2009 is the priority of the early prescription of antivirals, preventing the unjustified use of antibiotics. Objective: To describe the symptomatology that is associated more with the definitive diagnosis of Influenza and to compare the performance of the clinical diagnosis against the diagnosis thrown by the rapid test. Material and methods A retrospective, cross-sectional, descriptive and analytical study. All patients with presumptive diagnosis of Influenza admitted to the Emergency Service of the Hospital Español de Mexico were included in two consecutive seasons from October 2016 to March 2017 and October 2017 to March 2018. Two groups were formed of the included patients: patients with positive PCR (group A) and patients with negative PCR (group B). Results A total of 857 patients with presumptive clinical diagnosis of influenza were obtained, of whom 537 were confirmed with Influenza by PCR (group A) and 320 were negative for the test (group B). The syndrome consisting of cough, fever, rhinorrhea and arthralgia has a specificity of 92.2% compared to the rapid test of 99.1%. Conclusions The syndrome characterized by cough, fever, rhinorrhea, arthralgia present during winter months has a high specificity for an infection by the Influenza virus.

Clipaje endoscópico de la arteria esfenopalatina para el tratamiento de la epistaxis posterior / Endoscopic sphenopalatine artery ligation for posterior epistaxis

Resumen Antecedentes Los casos de epistaxis posterior representan alrededor del 10 al 20% de las epistaxis. El tratamiento convencional para este tipo de padecimientos son los taponamientos nasales. El abordaje quirúrgico (cauterización y/o clipaje) está indicado cuando existe falla del tratamiento médico convencional; sin embargo, en la actualidad, se considera como primera opción. Material y métodos Se revisaron todos los casos de epistaxis posterior tratados en el Hospital Español de México de enero de 2007 a enero de 2017. Se realizó estadística descriptiva e inferencial para comparar al grupo conservador (taponamiento nasal) versus el grupo quirúrgico (clipaje). Resultados Se revisaron 242 expedientes; de ellos, se excluyeron 108. Se incluyeron 134 pacientes: 96 correspondieron al grupo quirúrgico y 38 al conservador. El 60.20% perteneció al género masculino y el 39.80% al femenino. La media para la edad fue de 60 años. El grupo quirúrgico (3.4 ± 1.9 días) requirió menos días de estancia hospitalaria en comparación con el conservador (4.8 ± 3.0 días), p < 0.01. Los pacientes con una epistaxis del lado derecho en el grupo quirúrgico tuvieron un mayor tiempo quirúrgico (p = 0.001) y más días de estancia hospitalaria (p = 0.006). Conclusiones La epistaxis sucede en la mayoría de los casos de forma idiopática; es frecuente en hombres mayores de 60 años con enfermedades cardiopulmonares, sin conocerse de forma precisa su fisiopatología. La epistaxis derecha tratada quirúrgicamente resulta tener más morbilidad. El abordaje quirúrgico es seguro, eficaz y acorta los días de estancia hospitalaria en comparación con el tratamiento conservador.

Abstract Background The cases of posterior epistaxis represent approximately 10 to 20% of all epistaxis. The conventional treatment for this type of ailment is nasal packing. A surgical approach (cauterization and/ or clipping) is indicated when there is a failure of the conventional medical treatment; however, it is currently considered as the first option. Material and methods All the epistaxis cases treated at the Hospital Español de México from January 2007 to January 2017 were reviewed. Descriptive and inferential statistics were used to compare the conservative group (nasal packing) versus the surgical one (clipping). Results 242 dossiers were reviewed, of which 108 were excluded. 134 patients were included: 96 belonged to the surgical group and 38 to the conservative one. 60.20% were male and 39.80% were female. The mean age was 60 years. The surgical group (3.4 ± 1.9 days) required fewer days of hospital stay compared to the conservative group (4.8 ± 3.0 days), p < 0.01. Patients with right-sided epistaxis in the surgical group had a longer surgical time (p = 0.001) and more days of hospital stay (p = 0.006). Conclusions Epistaxis occurs in most cases idiopathically, often in men over 60 years with cardiopulmonary diseases, without a precise knowledge of its physiopathology. Right epistaxis treated surgically results in more morbidity. The surgical approach is safe, effective and shortens the days of hospital stay compared to the conservative treatment.

Association between Stable Coronary Artery Disease and In Vivo Thrombin Generation.

Background. Thrombin has been implicated as a key molecule in atherosclerotic progression. Clinical evidence shows that thrombin generation is enhanced in atherosclerosis, but its role as a risk factor for coronary atherosclerotic burden has not been proven in coronary artery disease (CAD) stable patients. Objectives. To evaluate the association between TAT levels and homocysteine levels and the presence of coronary artery disease diagnosed by coronary angiography in patients with stable CAD. Methods and Results. We included 95 stable patients admitted to the Haemodynamics Department, including 63 patients with significant CAD and 32 patients without. We measured the thrombin-antithrombin complex (TAT) and homocysteine concentrations in all the patients. The CAD patients exhibited higher concentrations of TAT (40.76 µg/L versus 20.81 µg/L, p = 0.002) and homocysteine (11.36 µmol/L versus 8.81 µmol/L, p < 0.01) compared to the patients without significant CAD. Specifically, in patients with CAD+ the level of TAT level was associated with the severity of CAD being 36.17 ± 24.48 µg/L in the patients with bivascular obstruction and 42.77 ± 31.81 µg/L in trivascular coronary obstruction, p = 0.002. Conclusions. The level of in vivo thrombin generation, quantified as TAT complexes, is associated with the presence and severity of CAD assessed by coronary angiography in stable CAD patients.

[Involvement of matrix metalloproteinases in acute coronary syndrome (ACS)]. / Participación de las metaloproteinasas de matriz en el síndrome isquémico coronario agudo (SICA).

Matrix metalloproteinases (MMP) are enzymes that degrade extracellular matrix (ECM) proteins and regulate both their accumulation and composition. The MMP are involved in the atherosclerotic process since they contribute to the formation of the plaque and its subsequent rupture. This last step triggers the myocardial ischemia that will be clinically reflected as an acute coronary syndrome (ACS). Thus, MMP activity is a key to whether ACS develops or not. With an elevated transcription rate of the genes that codify these proteinases comes a higher enzymatic activity. This explains that if a polymorphism in the mentioned genes modifies transcription, there could be a predisposition to developing ACS. Several studies reveal that certain genetic variations in MMP-1, -2, -3, -7, -8, -9, -12, and -14 have an important role either as risk factors or as protective factors for the expression of ACS.

[Relationship between urinary incontinence and pelvic organ prolapse]. / Relación entre incontinencia urinaria y prolapso de órganos pélvicos.

BACKGROUND: Urinary incontinence affects up to 70% of women and pelvic organ prolapse has a prevalence of 41% in postmenopausal women over 60 years, but most are not clinically affected. OBJECTIVE: Sought to assess the relationship of pelvic organ prolapse in patients with urinary incontinence diagnosed by urodynamic and which of the sub-types is related to a greater extent. MATERIAL AND METHODS: We performed an observational, retrospective, descriptive, in which we reviewed records of patients with symptoms of urinary incontinence undergoing urodynamic study, evaluating a total of 85 patients. RESULTS: Prolapse was noted in mixed incontinence by 80%, compared to 46.9% with urge incontinence or stress incontinence 34.9%, p 0.034. 89.5% of women with prolapse had some form of incontinence, associated with an OR = 2.38 (CI 1844-3078, p = 0.023).

The matrix metalloproteinase 2-1575 gene polymorphism is associated with the risk of developing myocardial infarction in Mexican patients.

AIM: Was to evaluate the role of seven matrix metalloproteinase (MMP) polymorphisms in the genetic susceptibility to develop myocardial infarction in Mexican individuals. METHODS: Seven polymorphisms in the MMP genes were genotyped by 5' exonuclease TaqMan genotyping assays in 300 patients with myocardial infarction and 300 healthy unrelated controls. RESULTS: A similar distribution of MMP2-1306 (rs243865), MMP2-790 (rs243864), MMP2-735 (rs22850553), MMP7-153(rs11568819), MMP7-181(rs11568818), and MMP12-82(rs2276109) polymorphisms was observed in both studied groups. On the other hand, patients showed increased frequencies of MMP2-1575 A allele and AA genotype when compared to controls (pC= 0.001; OR= 1.58 and pC= 0.036; OR= 2.37, respectively). According to the dominant model, individuals with AG+AA genotypes had a 1.65-fold increased risk of developing the disease (p= 0.002). After adjusting for known risk factors, we found a significant contribution of gender, BMI, smoking habit, diabetes mellitus, and hypertension to the inheritance model. In this analysis, individuals with the-1575 AA genotype had a 4.23-fold increased risk of developing MI (p= 0.003). On the other hand, an association of the MMP12-82 polymorphism with the extent of coronary artery disease (CAD) was observed. In our study, it was possible to distinguish two risk haplotypes and one protective haplotype for this disease in the MMP2 gene. CONCLUSIONS: The results suggest that the MMP2-1575 (rs243866) gene polymorphism could be involved in the risk of developing myocardial infarction in Mexican individuals.

Lipoprotein(a) and homocysteine potentiate the risk of coronary artery disease in male subjects.

BACKGROUND: Lipoprotein (Lp(a)) and homocysteine (Hcy) are independent risk factors for coronary artery disease (CAD). Hcy promotes the release of free apo(a) from Lp(a). The high fibrin affinity of free apo(a) inhibits plasminogen binding and plasmin generation. Hyperhomocysteinemia can result from a less active variant of methylene tetrahydrofolate reductase (variant C677T). Because the C677T genotype is estimated to be present in 32.2% of the Mexican population, we took advantage of this prevalence to determine the possible potentiating effect between high plasma Lp(a) and Hcy for increasing the risk of CAD in male patients. METHODS AND RESULTS: First, 222 male patients admitted for coronary angiography were recruited and classified as CAD+ or CAD-. Anthropometric measurements, traditional risk factors, and plasma total Hcy (tHcy) and Lp(a) levels were recorded in both groups. We performed a conditional logistic regression model adjusted for conventional risk factors of CAD and it became clear that Lp(a) ≥30mg/dl was a risk factor for CAD (odds ratio [OR] 5.06, 95% confidence interval [CI] 1.88-13.51, P=0.001), whereas Hcy was not related to CAD (OR 0.44, 95% CI 0.63-2.90, P=0.44). However, when both factors were considered together in an interaction model, high tHcy and high Lp(a) plasma concentrations showed a potentiated effect (OR 10.52, 95% CI 2.18-50.71, P=0.003). CONCLUSIONS: The combination of high Lp(a) and Hcy levels synergistically increases the likelihood of developing CAD in male patients.

Homocysteine is related to aortic mineralization in patients with ischemic heart disease.

UNLABELLED: Homocysteine is implicated as an early atherosclerotic promoter, which enhances the smooth muscle cell proliferation and produces free radicals that induce cellular damage. These factors must have a role in the progression of atherosclerosis that subsequently leads to vascular mineralization. AIM: Identify a correlation between the plasma concentration of total homocysteine and the amount of minerals that accumulate in the aorta of patients with atherosclerosis. METHODS: We performed a cross-sectional study in 13 patients with three-vessel coronary artery disease, undergoing coronary artery bypass surgery. Aortic and mammary artery specimens were analyzed using a scanning electron microscope with an energy dispersive X-ray spectrometer. The homocysteine was determined using an immunonephelometry method. RESULTS: The amount of minerals in the aorta was greater (300 ± 181.6 particles per 500 µm2 than that in the mammary artery (64 ± 45 particles per 500 µm2 (p < 0.01). The average tHcy was 9.5 ± 2.3 µmol/L. The Spearman's rank correlation coefficient was positive between tHcy, and aortic iron (p < 0.05). CONCLUSIONS: Our study demonstrates that the aorta is dramatically affected by mineralization compared to the mammary artery. In addition, a direct correlation was identified between the levels of tHcy and the iron particles in the aortic wall.

Aortic mineralisation in children with congenital cardiac disease.

BACKGROUND: Congenital cardiac diseases are the most frequent congenital malformations. In adult patients, the mineralisation of the aorta due to cardiovascular disease is very common, but vascular mineralisation in paediatric cardiopathies is a topic less studied. This study shows that children with a complex congenital cardiopathy show a high degree of vascular mineralisation in the ascending aorta. This can be part of the cardiac failure pathophysiology due to congenital cardiopathies. OBJECTIVE: The aim of this study was to determine the presence and degree of vascular mineralisation in samples of the ascending and descending aorta of children with complex congenital cardiopathies. DESIGN: We conducted a cross-sectional study. SUBJECTS: We obtained 34 vascular tissues from the autopsies of 17 children with congenital cardiac disease. METHODS: We used a scanning electron microscope with an energy-dispersive X-ray spectroscopy in order to analyse the vascular tissues. RESULTS: The amount of minerals was two times higher in the ascending aorta than in the descending aorta of children with congenital cardiac disease. CONCLUSIONS: The study provides evidence that vascular mineralisation can start at an early age, and that it is higher in the ascending aorta than in the descending aorta.

Platelet aggregation in whole blood, a new approach for understanding the antiplatelet effect of N-(3-hydroxy-1,3,5(10)-estratrien-17b-yl) butylamine (buame).

We have previously reported the effect of a compound derived from estradiol containing a radical amino butyl at the 17-beta position which has shown anticoagulant effects in whole blood and antiplatelet effects in light transmission aggregometry where platelets are isolated from other blood cells. In contrast, whole blood aggregometry includes the platelet interactions with blood elements such as erythrocytes and leukocytes. We examined the cooperative effect between leukocytes, erythrocytes and platelets and the antiplatelet effect of Buame in whole blood aggregometry, a tool to assess platelet function in its physiological environment. Buame (5-500 microM) dissolved in DMSO was tested in platelet aggregation induced by ADP (1.25 microM) or collagen (1 microg/mL) and the response recorded over 5 min. Controls were run with DMSO and the average control aggregation was taken as 100%. Results were obtained in both whole blood and platelet aggregometry. Buame was able to inhibit the secondary aggregation induced with ADP suggesting impairment in thromboxane A2 production. Also the first and second aggregation phases were inhibited when collagen-induced platelet activation was employed. This concentration-dependent pattern was shown in both whole blood and platelet aggregometry assays. When tested in light transmission aggregometry, a higher concentration of Buame was required in order to inhibit to the same degree ADP- or collagen-induced platelet aggregation (30 microM ,114 microM) than that required in the whole blood assay (IC50 84 microM, 191 microM). Interactions among different cell types in whole blood may modify the response of Buame-treated platelets to agonists suggesting a cooperative mechanism.