Prognostic Value of a Laboratory Index of Frailty in Older Patients Hospitalized for COVID-19: The COMEPA Study.

BACKGROUND: Several indexes based on clinical and laboratory tests to identify frailty and to predict mortality have been produced. Only two studies, mixing clinical and laboratory parameters were made about a frailty index made of laboratory tests (FI-Lab) and mortality in older patients hospitalized for COVID-19. The aim of this study was to explore the accuracy and precision of an FI-Lab constructed with some common bio-humoral tests and mortality in a cohort of patients hospitalized for COVID-19. METHODS: The FI-Lab was constructed using 40 different bio-humoral tests during the first four days of hospitalization, with a score from 0 to 1. The association between FI-Lab and mortality was assessed using a multivariate Cox's regression analysis, reported as hazard ratios (HRs) and 95% confidence intervals (CIs). The accuracy of the FI-Lab was reported as area under the curve (AUC) and the precision with the C-Index. RESULTS: 376 patients (mean age: 65 years; 53.7% males) were initially included. During the follow-up period, 41 deceased. After adjusting for five different factors, an FI-Lab value >0.54, the median value of our cohort, was associated with a relative risk about five times greater than lower values. Modeling FI-LAB as a continous variable, each increase in 0.01 points was associated with an increased risk in mortality of 8.4% (HR=1.084; 95%CI: 1.039-2.044). The FI-Lab was highly accurate (AUC=0.91; 95%CI: 0.87-0.95) and precise (C-Index=0.81) in predicting death. CONCLUSIONS: A simple index based on common laboratory tests can be used to predict mortality among older people hospitalized for COVID-19.

Baseline metabolic disturbances and the twenty-five years risk of incident cancer in a Mediterranean population.

BACKGROUND AND AIMS: Obesity is predictive of metabolic syndrome (metS), type 2 diabetes, cardiovascular (CV) disease and cancer. The aim of the study is to assess the risk of incident cancer connected to obesity and metS in a Mediterranean population characterized by a high prevalence of obesity. METHODS AND RESULTS: As many as 1133 subjects were enrolled in two phases and followed for 25 years (859 subjects) or 11 years (274 subjects) and incident cancer was registered in the follow-up period. Anthropometric measures and biochemical parameters were filed at baseline and evaluated as predictors of incident cancer by measuring hazards ratios (HR) using multivariate Cox parametric hazards models. Best predictive threshold for metabolic parameters and metS criteria were recalculated by ROC analysis. Fasting Blood Glucose >5.19 mmol/L [HR = 1.58 (1.0-2.4)] and the TG/HDL ratio (log10) (Males > 0.225, Females > 0.272) [HR = 2.44 (1.3-4.4)] resulted independent predictors of survival free of cancer with a clear additive effect together with age classes [45-65 years, HR = 2.47 (1.3-4.4), 65-75 years HR = 3.80 (2.0-7.1)] and male gender [HR = 2.07 (2.3-3.1)]. CONCLUSIONS: Metabolic disturbances are predictive of cancer in a 25 years follow-up of a Mediterranean population following a traditional Mediterranean diet. The high prevalence of obesity and metS and the observed underlying condition of insulin resistance expose this population to an increased risk of cardiovascular disease and cancer despite the healthy nutritional habits.

Postprandial hyperglycemia is a determinant of platelet activation in early type 2 diabetes mellitus.

BACKGROUND: Chronic hyperglycemia is a major contributor to in vivo platelet activation in diabetes mellitus. OBJECTIVES: To evaluate the effects of acarbose, an alpha-glucosidase inhibitor, on platelet activation and its determinants in newly diagnosed type 2 diabetic patients. METHODS: Forty-eight subjects (26 males, aged 61 +/- 8 years) with early type 2 diabetes (baseline hemoglobin A(1c) < or = 7% and no previous hypoglycemic treatment) were randomly assigned to acarbose up to 100 mg three times a day or placebo, and evaluated every 4 weeks for 20 weeks. The main outcome measures were urinary 11-dehydro-thromboxane (TX)B(2) (marker of in vivo platelet activation) and 8-iso-prostaglandin (PG)F(2alpha) (marker of in vivo lipid peroxidation) excretion rate, 2-h postprandial plasma glucose (PPG) after a test meal, and assessment of glucose fluctuations by mean amplitude of glycemic excursions (MAGE). RESULTS: Baseline measurements revealed biochemical evidence of enhanced lipid peroxidation and platelet activation. As compared with the placebo group, patients treated with acarbose had statistically significant reductions in urinary 11-dehydro-TXB(2) and 8-iso-PGF(2alpha) excretion rate as early as after 8 weeks and at each subsequent time point (between-group P < 0.0001 at 12, 16 and 20 weeks), following earlier decreases in PPG and MAGE. Multiple regression analyses in the acarbose group revealed that PPG was the only significant predictor of 11-dehydro-TXB(2) urinary excretion rate (beta = 0.39, P = 0.002) and MAGE the only predictor of 8-iso-PGF(2alpha) urinary excretion rate (beta = 0.42, P = 0.001). CONCLUSIONS: Postprandial hyperglycemia is associated with enhanced lipid peroxidation and platelet activation in early type 2 diabetes. A moderate decrease in PPG achieved with acarbose causes time-dependent downregulation of these phenomena, suggesting a causal link between early metabolic abnormalities and platelet activation in this setting.

Giant fibrothecoma--an interesting case.

A 45-year-old woman came for specialized medical attention due to intraabdominal pathology that began in 2003. Studies indicated the presence of a cyst in the right ovary, for which she was referred for surgery. She did not undergo the surgery and for a period of two years she suffered from an excessively enlarged abdomin. Posterior ultrasound studies indicated the presence of fibromatosis and she was again referred for surgery. Laparatomy was carried out and a giant cyst was found in the right ovary attached to the omentum, intestine, appendix, posterior side of the abdominal wall and to the uterus. We proceeded to remove the cyst and successively total abdominal hysterectomy and bilateral salpingo-oophorectomy were performed. Post surgery, the patient progressed well taking pertinent prophylatic measures. The histopathology report diagnosed a giant fibrothecoma weighing 30 pounds, together with endometrial hyperplasia and leiomyomas. The international literature reports that the incidence of these tumors is low, 5% of ovarian tumors, and even lower for functioning tumors as in this case.

Relapses of hyperthyroidism in patients treated with radioiodine for nodular toxic goiter: relation to thyroid autoimmunity.

Relapses of hyperthyroidism after treatment with radioiodine for uni- or multi-nodular goiter may be accompanied by the appearance of TSAb. However, this phenomenon has only emerged from one retrospective study on Northern European patients, in which it was not possible to determine whether TSAb also appeared in treated patients who did not relapse. The present study aimed to assess the appearance, immunogenic nature and clinical characteristics of hyperthyroidism relapse after treatment with 131I for nodular toxic goiter in patients from the Mediterranean area. A retrospective study was performed on 76 consecutive patients, born and resident in Sicily and aged 56-80 yr at diagnosis, who were treated with radioiodine. Serum aliquots obtained from the patients before 131I treatment and during a follow-up of 36-144 months were assayed for TSAb and TPOAb. The clinical charts of the patients were also re-examined. Twenty-six out of 76 patients (36.8%) had a hyperthyroidism relapse after a first treatment with 131I. Eight of the 26 (30.7%) also relapsed after the second treatment. Three out of 26 (11.5%) relapsed after a third treatment. The 50 patients who required only one treatment and the 18 who relapsed only once were all TSAb-negative at baseline, while 3/8 (37.5%) who relapsed also after the second treatment were already TSAb-positive at baseline. TSAb became positive in 3/18 patients (16.7%) who relapsed once, and in 4/8 (50.0%) of those who relapsed after a second treatment. One of these 7 TSAb-positive relapsers was also already TPOAb-positive at baseline and another became TPOAb-positive after treatment. The presence of circulating TSAb in 3/76 (3.9%) patients before treatment for toxic goiter more probably points to a diagnosis of Marine-Lenhart's syndrome. In contrast, the de novo appearance of TSAb in the presence of hyperthyroidism relapse in 4/76 (5.3%) patients suggests the development of a Graves'-like disease after radioiodine treatment. This occurrence does not seem to have precise ethnic grounds, since the incidence we observed in Mediterranean patients was similar to that previously reported in Northern European patients.

Glycemic homeostasis in chronic viral hepatitis and liver cirrhosis.

OBJECTIVES: This study aimed at investigating the respective impacts of virus-related chronic hepatitis (CH) and liver cirrhosis (LC) on glycemic homeostasis, with reference to grading and/or staging of liver disease and to contribution of the two main responsible viruses. MATERIAL AND METHODS: The glycometabolic features of 82 patients with CH (B-related 16, and C-related 66) and 145 with LC (B-related 24, and C-related 121) were evaluated. RESULTS: Impaired glucose tolerance (IGT) was detected in 9 (11.0%) and diabetes mellitus (DM) in 6 (7.3%) of the CH patients [(P<0.05 vs controls, in both cases; respective odds ratios (95% CI): 2.6 (1.1-6.3), and 4.0 (1.2-13.2)]. IGT was detected in 86 (59.3%) and DM in 34 (23.4%) of the LC patients [(P=0.000 vs controls, in both cases; respective odds ratios: 10.0 (7.0-14.4), and 5.5 (3.5-8.5)]. The odds ratios for the prevalence of IGT and DM in the LC patients were 11.8 (5.2-27.5) and 3.9 (1.5-10.8), compared with the CH patients. In the CH patients, glycometabolic failure was significantly related to age (P=0.026), but not to grading and staging, and in the LC patients to Pugh-Child score (P=0.037). IGT was found in 17/40 (42.5%) HBV-related patients and in 13/40 (32.5) matched HCV-related patients. DM was found in 9/40 (22.5%) HBV-related patients and in 10/40 (25.0%) HCV-related matched patients, without significant difference in the respective proportions. CONCLUSION: The prevalence of DM associated to virus-related CH is on average four times higher than in the general population, independently of the histopathological picture of disease. Virus-related LC further increases the prevalence of both IGT and DM, independently of sex and age, but in relationship with the severity of disease. HBV and HCV infections do not appear to have a different impact on glycemic homeostasis.

Determinants of enhanced thromboxane biosynthesis in renal transplantation.

BACKGROUND: Despite great improvement in patient and graft survival, the long-term morbidity and mortality in renal transplant recipients (RTRs) are still significant, with a high incidence of cardiovascular disease-related deaths. METHODS: We investigated thromboxane (TXA2) biosynthesis and endothelial and coagulative activation in 65 patients who received a renal transplant. RESULTS: The rate of TXA2 biosynthesis (urinary 11-dehydro-TXB2 excretion largely reflects platelet TXA2 production in vivo) was significantly (P < 0.0001) higher in RTRs than in healthy subjects. Plasma von Willebrand factor (vWF) and thrombin-antithrombin (TAT) complexes were significantly higher (P < 0.001) in RTRs compared with controls. Urinary 11-dehydro-TXB2 directly correlated with plasma vWF and cholesterol. We next examined the relative influence of cyclosporine A (CsA) on TXA2 biosynthesis and endothelial activation, comparing a group of RTRs not receiving CsA with an age- and sex-matched group of patients treated with CsA. Urinary excretion of 11-dehydro-TXB2 and plasma levels of vWF were significantly increased in RTRs who received CsA compared with those who did not. After an overall follow-up of 120 months, RTRs who experienced cardiovascular events had a higher frequency of abnormal plasma levels of vWF than patients who remained event free. CONCLUSION: Renal transplantation is associated with in vivo platelet activation highly related to endothelial activation. This is particularly evident in CsA-treated patients. Administration of drugs that are able to reduce or eliminate thromboxane-dependent platelet activation in vivo may be beneficial to reduce the risk of cardiovascular events in RTRs.

In vivo lipid peroxidation and platelet activation in cystic fibrosis.

F(2)-isoprostanes are bioactive peroxidation products of arachidonic acid whose urinary excretion provides an index of lipid peroxidation in vivo. We tested the hypothesis that formation of F(2)-isoprostanes is altered in patients with cystic fibrosis and contributes to platelet activation and pulmonary dysfunction in this setting. The urinary excretion of immunoreactive 8-iso-prostaglandin F(2alpha) (PGF(2alpha)) was significantly (p = 0.0001) higher in 36 patients with cystic fibrosis than in 36 age-matched healthy subjects: 618 +/- 406 versus 168 +/- 48 pg/mg creatinine. The urinary excretion of immunoreactive 11-dehydro-thromboxane B(2) (TXB(2)), an index of in vivo platelet activation, was also significantly (p = 0.0001) higher in patients than in control subjects: 2,440 +/- 1,453 versus 325 +/- 184 pg/mg creatinine. The excretion rate of 8-iso-PGF(2alpha) was correlated with that of 11-dehydro-TXB(2) (rho = 0.51; p = 0.0026) and inversely related to FEV(1) (rho = -0.40; p = 0.0195). Urinary 8-iso-PGF(2alpha) excretion was largely unaffected during cyclooxygenase inhibition with low-dose aspirin, nimesulide, or ibuprofen, consistent with a noncyclooxygenase mechanism of F(2)-isoprostane formation in cystic fibrosis. Increased vitamin E supplementation (from 200 to 600 mg/d) was associated with statistically significant (p = 0.005) reductions in urinary 8-iso-PGF(2alpha) and 11-dehydro-TXB(2) excretion, by 42% and 29%, respectively. We conclude that enhanced lipid peroxidation is an important feature of cystic fibrosis and may contribute to persistent platelet activation and pulmonary dysfunction via generation of bioactive isoeicosanoids. Our results provide a rationale for reassessing the adequacy of vitamin E supplementation in this setting.

Tumor Carcinoide en el mediastino anterior: presentación de un caso y revision de la literatura / Carcinoid tumor in the anterior mediastinum: report of a case and review of the literature

The Carcinoide tumors are infrequent. The come from neuroendocrine argentafine cells, probably related to cells of the APUD system. They are rarely found in the mediastinum. We are reporting a case, and bringing forward some biological, epidemiological and clinical characteristics. We also emphasize over the diagnosis and treatment, and the basics to evaluate the prognosis

[Carcinoid tumor in the anterior mediastinum. Report of a case and review of the literature]. / Tumor Carcinoide en el mediastino anterior. Presentación de un caso y revision de la literatura.

The Carcinoide tumors are infrequent. The come from neuroendocrine argentafine cells, probably related to cells of the APUD system. They are rarely found in the mediastinum. We are reporting a case, and bringing forward some biological, epidemiological and clinical characteristics. We also emphasize over the diagnosis and treatment, and the basics to evaluate the prognosis.

Thromboxane biosynthesis, neutrophil and coagulative activation in type IIa hypercholesterolemia.

Thromboxane (Tx) A2 biosynthesis is enhanced in the majority of patients with type IIa hypercholesterolemia. Because blood clotting activation is an important component of the inflammatory response, involved in the initiation and progression of atherosclerotic plaques, we have investigated TxA2 biosynthesis, neutrophil activation and thrombin generation in 24 patients with type IIa hypercholesterolemia. Urinary 11-dehydro-TxB2, was significantly higher (p = 0.0001) in patients than in 24 sex- and age matched healthy subjects. Similarly, prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin III complexes and plasma elastase were significantly higher in patients than in controls. Urinary 11-dehydro-TxB2 excretion was correlated with plasma elastase (r = 0.758; p = 0.0001), and prothrombin fragment 1 + 2 (r = 0.804; p = 0.001). The enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor simvastatin (20 mg/day for 2 months) significantly reduced cholesterol levels, urinary 11-dehydro-TxB2 excretion, plasma elastase and plasma F1 + 2 in 8 patients. We conclude that type IIa hypercholesterolemia is associated with biochemical evidence of platelet, neutrophil and blood clotting activation. The relationship between these events remains to be investigated.

Effects of nabumetone on prostanoid biosynthesis in humans.

BACKGROUND: The active metabolite of the anti-inflammatory drug nabumetone has been characterized as a selective inhibitor of the inducible prostaglandin H synthase (PGHS). The aim of this study was to investigate the rate of eicosanoid biosynthesis after oral dosing with nabumetone in nine healthy subjects. METHODS: We measured the urinary excretion of products of platelet (11-dehydro-thromboxane B2 [TXB2]) and renal (prostaglandin IF2 alpha [PGF2 alpha]) arachidonate metabolism as in vivo indexes of the constitutive PGHS-1 pathway. Moreover, the production of TXB2 during whole blood clotting was assessed as an index of the cyclooxygenase activity of platelet PGHS-1 ex vivo. RESULTS: At steady state, nabumetone (500 and 1000 mg daily for 7 days) was associated with statistically significant dose-dependent reduction in the urinary excretion of 11-dehydro-TXB2 and serum TXB2 levels by approximately 50% to 70%. However, the drug did not significantly affect the urinary excretion of PGF2 alpha. After discontinuation of nabumetone, urinary 11-dehydro-TXB2 excretion and whole blood TXB2 production returned to predrug levels with a similar timecourse that was consistent with the elimination half-life of its active metabolite. The daily administration of low-dose aspirin (40 mg), a selective inhibitor of platelet PGHS-1, caused a cumulative inhibition of urinary 11-dehydro-TXB2 and whole blood TXB2 production that recovered with a timecourse consistent with platelet turnover. CONCLUSIONS: Nabumetone does dose-dependently inhibit the cyclooxygenase activity of platelet PGHS-1 of healthy subjects both in vivo and ex vivo. Thus it is unlikely that its safety profile in patients may be related to selective inhibition of the inducible PGHS-2.

Demonstration of Rickettsia Conorii-induced coagulative and platelet activation in vivo in patients with Mediterranean spotted fever.

Endothelial injury in vivo induced by Rickettsia Conorii, the etiologic agent of Mediterranean Spotted Fever (MSF) has been recently demonstrated. We sought to determine whether platelet and/or coagulative activation in vivo can be demonstrated in the acute phase of MSF, through measurements of a major metabolite of thromboxane (TX) in the urine (11-dehydro-TXB2) and of plasma prothrombin fragment 1 + 2, whose levels reflect activation of prothrombin to thrombin. Moreover, we measured plasma endothelin-1 as marker of endothelial dysfunction. Our results provide biochemical evidence for the occurrence of TXA2-dependent platelet activation and thrombin generation in vivo, together with endothelial dysfunction. These phenomena could account for clinical manifestations of MSF, such as vasculitis and focal microthrombus formation. These results could also provide a rationale for testing the efficacy of aspirin or heparin in reducing the prothrombotic status of Rickettsiae diseases.

Inhibition of thromboxane biosynthesis and platelet function by simvastatin in type IIa hypercholesterolemia.

Thromboxane A2 (TXA2) biosynthesis is enhanced in the majority of patients with type IIa hypercholesterolemia. Because simvastatin (a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor) was previously shown to reduce platelet aggregation and TXB2 production ex vivo, we investigated TXA2 biosynthesis and platelet function in 24 patients with type IIa hypercholesterolemia randomized to receive in a double-blind fashion simvastatin (20 mg/d) or placebo for 3 months. The urinary excretion of 11-dehydro-TXB2, largely a reflection of platelet TXA2 production in vivo, was measured by a previously validated radioimmunoassay technique. Blood lipid levels and urinary 11-dehydro-TXB2 excretion were significantly (P < .001) reduced by simvastatin. In contrast, placebo-treated patients did not show any statistically significant changes in either blood lipids or 11-dehydro-TXB2 excretion. The reduction in 11-dehydro-TXB2 associated with simvastatin was correlated with the reduction in total cholesterol (r = .81, P < .0001), LDL cholesterol (r = .79, P < .0001), and apolipoprotein B (r = .76, P < .0001) levels. Platelets from patients with type IIa hypercholesterolemia required significantly (P < .01) more collagen and ADP to aggregate and synthesized less TXB2 in response to both agonists after simvastatin therapy. Bleeding time, platelet sensitivity to Iloprost, and blood lipoprotein(a) and HDL cholesterol levels were not significantly affected by either treatment. We conclude that enhanced TXA2 biosynthesis in type IIa hypercholesterolemia is, at least in part, dependent on abnormal cholesterol levels and/or other simvastatin-sensitive mechanisms affecting platelet function.

Biochemical and pharmacological characterization of the cyclooxygenase activity of human blood prostaglandin endoperoxide synthases.

The aim of our study was to characterize a model of human prostaglandin endoperoxide synthase-2 (PGHS-2) expression allowing the assessment of pharmacological inhibition in vitro and ex vivo. Heparinized human whole blood samples were incubated with lipopolysaccharide (LPS, 0.1-50 micrograms/ml) for 0 to 24 hr at 37 degrees C. The contribution of platelet PGHS-1 was suppressed by either pretreating the subjects with aspirin (300 mg 48 hr before sampling) or adding aspirin (10 micrograms/ml) in vitro at time 0. PGE2 was measured by radioimmunoassay. LPS induced expression of cyclooxygenase activity in a time- and concentration-dependent fashion. After 24 hr at 10 micrograms/ml LPS, PGE2 production averaged 12.1 +/- 6.2 ng/ml (mean +/- S.D., n = 7). Cyclooxygenase activity increased in parallel with the mass of a monocyte protein doublet analyzed by Western blot using antibodies directed against the carboxyl-terminal portion of human PGHS-2. Dexamethasone (2 microM) inhibited LPS-induced PGE2 production by 96 +/- 4% (mean +/- S.D., n = 3). Four different inhibitors were tested in vitro on the cyclooxygenase activity of LPS-induced monocyte PGH-2 and thrombin-stimulated platelet PGHS-1. IC50 values (microM) for inhibition of PGHS-1 and PGHS-2 were: indomethacin, 0.70 +/- 0.20 vs 0.36 +/- 0.10 (P < .05); S-indobufen, 0.64 +/- 0.22 vs. 14.9 +/- 8 (P < .05), R-indobufen, 38 +/- 18 vs. 230 +/- 68 (P < .01), 6-methoxy-2-naphthyl acetic acid (the active metabolite of nabumetone), 278 +/- 96 vs. 187 +/- 96.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of thromboxane biosynthesis and platelet function by indobufen in type II diabetes mellitus.

Indobufen is a reversible inhibitor of platelet prostaglandin G/H-synthase. To verify the dose dependence of the antiplatelet effect of indobufen on ex vivo and in vivo indexes of thromboxane (TX) biosynthesis and TXA2-dependent platelet function, we studied nine patients with non-insulin-dependent diabetes mellitus (NIDDM). This was a randomized, double-blind, crossover study in which each patient was treated with three different daily regimens (50 mg BID, 100 mg BID, and 200 mg BID) of indobufen for 1 week, with a 7-day washout period between treatments. Urinary 11-dehydro-TXB2 excretion averaged 58.2 +/- 21.8 ng/h at baseline. TX metabolite excretion was reduced dose dependently by indobufen: by 67% at 50 mg BID, 72% at 100 mg BID, and 81% at 200 mg BID. Platelet cyclooxygenase activity, ATP release, collagen-induced platelet aggregation, and bleeding time also were modified dose dependently by indobufen. Biochemical demonstration of suppressed platelet TXA2 in vivo was accompanied by evidence of inhibited platelet function as assessed ex vivo. Under pathophysiological conditions, such as NIDDM, which are associated with enhanced TXA2 synthesis, more than 95% suppression of platelet cyclooxygenase activity may be necessary to produce virtually maximal inhibition of platelet TXA2 biosynthesis in vivo.

Increased thromboxane biosynthesis in type IIa hypercholesterolemia.

BACKGROUND: Increased platelet thromboxane (TX)A2 production has been described in type IIa hypercholesterolemia. To verify the relevance of these capacity-related measurements to the actual rate of TXA2 biosynthesis in vivo, we studied the urinary excretion of its major enzymatic metabolites in 46 patients with type IIa hypercholesterolemia and 20 age-matched controls. METHODS AND RESULTS: Urinary 11-dehydro-TXB2 and 2,3-dinor-TXB2 were measured by previously validated radioimmunoassays. The excretion rate of 11-dehydro-TXB2 was significantly (p less than 0.001) higher in patients (68.7 +/- 35.1 ng/hr, mean +/- SD) than in controls (22.4 +/- 9.4 ng/hr), with metabolite excretion greater than 2 SD of the normal mean in 74% of the patients. Urinary 11-dehydro-TXB2 was significantly (p less than 0.01) correlated with the threshold aggregating concentration of collagen (r = -0.641) and arachidonate (r = -0.734) and with agonist-induced platelet TXB2 production in vitro (r = 0.647 and 0.748, respectively). Moreover, a statistically significant correlation (r = 0.673, p less than 0.001, n = 66) was found between 11-dehydro-TXB2 excretion and total plasma cholesterol. The enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor simvastatin (20 mg/day for 6 months) significantly reduced cholesterol levels by 22-28% and urinary 11-dehydro-TXB2 excretion by 32-42% in 10 patients. However, the reduction in the latter did not correlate with the reduction in the former and may have resulted from a nonspecific effect of simvastatin. Moreover, selective inhibition of platelet cyclooxygenase activity by low-dose aspirin (50 mg/day for 7 days) was associated with cumulative inhibition of 11-dehydro-TXB2 excretion by approximately 70% in six patients. CONCLUSIONS: TXA2 biosynthesis is enhanced in the majority of patients with type IIa hypercholesterolemia; this is, at least in part, a consequence of abnormal cholesterol levels, as suggested by the correlation between the two. Low-dose aspirin can largely suppress increased metabolite excretion, thus suggesting that it reflects TXA2-dependent platelet activation in vivo.