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P Ramirez

Publications and source records attributed to P Ramirez.

At least 19 recordsLinked to original sources
PubMed2006

Unexpected peripheral markers of thyroid function in a patient with a novel mutation of the MCT8 thyroid hormone transporter gene.

The specific thyroid hormone transporter, MCT8, located on the X chromosome, has led to the identification a novel syndrome. The objective is to relate phenotype with several tissue-specific thyroid functions. A 1-year-old boy, who had severe psychological damage and low serum T4, had received l-T4 for 3 months. At admission, body length was normal but weight was low. Off therapy, serum TSH was mildly elevated, serum T4 and free T4 were low, and serum T3 and free T3 were high. Direct sequencing of the MCT8 gene revealed a single nucleotide change that resulted in a novel nonsense mutation at codon 261 (Q261X) in exon 3. Since serum T3 was high, peripheral markers of hyperthyroidism were looked for. Bone age was advanced, despite the presence of malnutrition and low T4. Serum SHBG, a marker of thyroid hormone action in liver, was markedly elevated. Markers of skeletal muscle catabolism, ammonemia and lactic acid, were found to be elevated. The phenotype of MCT 8 mutation might be explained by differences in the entry of thyroid hormones into different cells. In the presence of an inactive MCT8 transporter, the high blood T3 levels might not be enough to prevent brain damage early in life, while they seem to be able to induce a postnatal state of peripheral hyperthyroidism in other tissues, such as liver, bone and skeletal muscle.

Age Determination by Skeleton↗
PubMed2005

Effects of dobutamine on right ventricular function and pulmonary circulation in pulmonary hypertension during liver transplantation.

INTRODUCTION: In the setting of orthotopic liver transplantation (OLT), pulmonary hypertension (PH) affects right ventricular (RV) function. When RV failure occurs, reducing RV afterload, optimizing RV preload, and preserving coronary perfusion through maintenance of systemic blood pressure are the primary goals of intraoperative treatment. PATIENTS AND METHODS: To verify the effect of dobutamine on RV function and RV-arterial coupling, we compared a group of 9 cirrhotic patients with mild PH treated with OLT to a group of 20 patients with normal mean pulmonary artery pressure (MPAP). All patients received dobutamine (5-10 microg/kg/min) to maintain a cardiac index (CI) >3 L/min/m(2), during the anhepatic phase. Hemodynamic profile, using a pulmonary artery catheter, was performed before and during dobutamine infusion, studying MPAP, CI, and RV end-diastolic volume index (RVEDVI). RV stroke work index (RVSWI), RV end-systolic elastance (Ees), pulmonary effective elastance (Ea), and RV-arterial coupling efficiency as the Ees/Ea ratio were also calculated. RESULTS: RV contractility (Ees and RVSWI) and afterload (Ea) were significantly higher among the PH group. In both groups, all the studied variables improved with dobutamine: RV contractility increased, afterload decreased, and thus Ees/Ea coupling markedly increased. CONCLUSION: Cirrhotic patients with mild PH who were undergoing OLT still have a reserve of RV contractile performance and pulmonary vasodilation.

Cardiotonic Agents↗
PubMed2005

Portopulmonary hypertension and liver transplantation: hemodynamic consequences at reperfusion.

BACKGROUND: The absence of portopulmonary hypertension (PH) upon preoperative evaluation for liver transplantation (OLT) does not exclude the occasional occurrence of an acquired PH while awaiting a graft. We sought to estimate hemodynamic changes and right ventriculoarterial coupling during reperfusion. METHODS: We studied 11 cirrhotic patients diagnosed with mild PH, according to the current classification: mean pulmonary artery pressure (MPAP)-25 to 34 mm Hg. These patients underwent OLT, using the piggyback technique (group PH). None of them had exhibited criteria for PH on preoperative echocardiography. This cohort was compared with 20 consecutive cirrhotic patients with normal MPAP at OLT. We performed a complete hemodynamic profile using a pulmonary artery catheter (RVEF, Baxter-Edwards, Calif, USA) before and 5 minutes after reperfusion. The variables were MPAP and right ventricular (RV) end-diastolic volume index (RVEDVI). Using standard formulas we calculated RV stroke work index (RVSWI), RV end-systolic elastance (Ees), pulmonary effective elastance (Ea), and RV-arterial coupling efficiency as the Ees/Ea ratio. Systolic ventricular function was expressed as RVSWI versus RVEDVI. RESULTS: During the anhepatic phase, MPAP, Ees, Ea, and RVSWI were higher in the PH group; but RVEDVI was lower. After reperfusion the pressure (MPAP), contractility (RVSWI) and preload (RVEDVI) increased in both groups. However, afterload (Ea) decreased in the non-PH group; accordingly, Es/Ea increased only in these patients. DISCUSSION: At reperfusion, the expansion in preload and cardiac output, without a similar afterload decrease, is responsible for the steady increase in pressure. Our results have shown that in the PH patient group, systolic ventricular function improves during reperfusion by a Frank-Starling mechanism; however, ventricular-arterial uncoupling is maintained (Ees/Ea < 1) because ventricular contractility is not appropriately balanced by simultaneous declines in afterload.

Hemodynamics↗
PubMed2005

Differential response of the systemic and pulmonary circulation related to disease severity of cirrhosis.

BACKGROUND: In cirrhotic patients, the degree of hepatic insufficiency has been related to a physiological landmark: arterial vasodilatation. We sought to assess how the severity of disease, which was stratified according to the Child-Pugh criteria, influences the pulmonary and systemic circulation among patients undergoing liver transplantation. METHODS: We studied 86 cirrhotic patients in three groups: grade A (n = 10), grade B (n = 54), and grade C (n = 22). The outurnes were classified based upon a complete hemodynamic profile obtained using a pulmonary artery catheter (RVEF, Baxter-Edwards, Calif, USA) after induction of anesthesia. The variables were mean arterial and pulmonary artery pressures and cardiac index (CI). Using standard formulae, afterload was calculated as elastance of systemic (Es) and pulmonary (Ep) arterial beds, expressed by the ratio of end-systolic pressure to stroke volume. The relation between pulmonary and systemic circulation was also evaluated by the ratio (Ep/Es). RESULTS: Es was significantly lower in each class than in previous one. Also, Ep was smaller in class B than in class C patients. In addition, CI was significantly higher with disease severity. CONCLUSION: We observed that the hyperdynamic circulation in cirrhosis is directly related to severity of disease. Nevertheless Ep/Es was progressively higher among each group; these data suggest that the hyperdynamic circulation is mainly due to circulatory alterations in the splanchnic area. We conclude that pulmonary vasodilatation is directly related to the severity of cirrhosis, although its evolution is independent of other vascular areas.

Blood Circulation↗
PubMed2003

Does the standard vs piggyback surgical technique affect the development of early acute renal failure after orthotopic liver transplantation?

The objective of this study was to evaluate the effect of the surgical technique on postoperative renal function during the first week after liver transplantation (OLT). We performed a retrospective study of 184 consecutive OLT. Criteria for acute renal failure were: serum creatinine >1.5 mg/dL, an increase by 50% in the baseline serum creatinine, or oliguria requiring renal replacement therapy. The distribution of patients according to the surgical technique was: standard (n=84), venovenous bypass (n=20), and piggyback (n=80). Other variables analyzed were: intraoperative requirement for blood products, treatment with adrenergic agonists, intraoperative complications, and postreperfusion syndrome. Univariate analysis showed the following parameters to be significantly related to postoperative renal failure: intraoperative fresh frozen plasma and cryoprecipitate requirements, intraoperative complications, postreperfusion syndrome, need for noradrenaline or dobutamine, standard surgical technique versus piggyback (39% vs 18%, P<.01) and venovenous vs piggyback (50% vs 18%, P<.01). Logistic regression analysis identified the following variables as having independent prognostic value: (1) Standard surgical technique vs piggyback (OR=3.3, P=.01); (2) venovenous vs piggyback (OR=4.7, P=.02); and (3) >20 U cryoprecipitate requirement (OR=1.04, P=.01). In conclusion, compared with the piggyback technique, the standard surgical technique appears to be an independent risk factor for postoperative acute renal failure. When venovenous bypass is used in patients who do not tolerate trial clamping of inferior vena cava, it does not reduce the incidence of postoperative renal failure. Finally, the piggyback technique significantly reduces the probability of acute renal failure after liver transplantation.

Acute Kidney Injury↗
PubMed2003

Eversion thromboendovenectomy for organized portal vein thrombosis encountered during liver transplantation.

INTRODUCTION: Due to the technical experience acquired in the field of liver transplantation portal vein thrombosis is no longer considered a contraindication for transplantation. Nevertheless, the results obtained in patients with portal vein thrombosis are at times suboptimal, and there is no consensus on the appropriate surgical technique. PATIENTS AND METHODS: Among the 455 liver transplants performed between May 1988 and December 2001, 32 (7%) presented with portal vein thrombosis. Twenty (62%) were type Ib, seven (22%) type II/III, and five (16%) type IV. Twenty-two were men (69%), with a mean age of 50 years (range: 30-70 years); the thrombosis in all cases developed in a cirrhotic liver. The surgical method in all cases consisted of an eversion thromboendovenectomy under direct visual guidance, with occlusion of the portal flow using a Fogarty balloon. RESULTS: Among the 32 cases undergoing thrombectomy, 31 (96%) were successful with a failure in a case of type IV thrombosis, which was resolved by portal arterialization. Of the 31 successful cases, only one with type IV thrombosis rethrombosed. The 5-year survival rate of the patients in the series was 69%. Only two patients died from causes related to the thrombosis, both showing type IV thrombosis. CONCLUSION: The ideal treatment for portal thrombosis during liver transplantation depends on its extension and on the experience of the surgeon. In our experience, eversion thromboendovenectomy resolves most thromboses (types I, II, and III), but management of type IV, which occasionally can be treated with this technique, may require more complex procedures such as bypass, portal arterialization or cavoportal hemitransposition.

Adult↗
PubMed2003

Relationship between CDC cross-match in liver recipients and antibody screening by flow cytometry.

Several authors have shown that anti-donor antibodies before liver transplantation are associated with decreased graft survival. The aim of this study was to investigate the relationship between anti-donor antibodies detected by the CDC technique or by FlowPRA, and acute or chronic rejection as well as graft survival. Furthermore, we sought to determine whether anti-donor antibodies, detected by the CDC technique, correlated with those discovered by cytometric screening. The acute rejection incidence among patients with complement-dependent cytotoxicity positive CDC cross-match was similar to that for patients with a negative cross-match. None of the patients with a positive cross-match developed chronic rejection. Allograft survival was significantly lower among recipients with a positive T-lymphocyte cross-match. Indeed, the majority of recipients with positive CDC cross-matches displayed graft failures before first posttransplant year. The results of a positive FlowPRA determination were concordant with a positive CDC cross-match in 85.71% of cases. Our data demonstrate that pretransplant FlowPRA correlates with the final CDC cross-match results. This finding suggests that in the future prospective pretransplant antibody screening with FlowPRA or CDC techniques may be useful to identify high-risk recipients.

Acute Disease↗
PubMed2003

Immunopathology of an hDAF transgenic pig model liver xenotransplant into a primate.

BACKGROUND: hDAF transgenic pigs do not display the inherent hyperacute rejection reactions of pig-to-primate xenotransplants. The purpose of this study was to determine the immunopathologic phenomena following an hDAF transgenic pig hepatic orthotopic xenotransplant into a baboon. METHODS: Donor animals were unmodified pigs (n=4) and hDAF transgenic pigs (n=2). Recipient animals were baboons (Papio anubis). Liver biopsies were immunostained using monoclonal antibodies to C3, C5b-9, IgG, IgM, CD2, CD4, CD8, CD68, CD20, Bric 216, CD31, and fibrin, and polyclonal antibody to C4. RESULTS: hDAF transgenic grafts showed IgG, IgM, and C4 endothelial deposits. However, no fibrin, C3, or C5b9 deposits were observed after reperfusion. hDAF xenografts displayed CD31 staining in the portal spaces, perilobular areas, and at hepatic sinuisoidal levels. The baboon that lived for 4 days displayed either CD4 or CD8 T-cells periportal infiltrate. CONCLUSIONS: Future studies will seek to determine the physiologic role of CD31 hepatic sinusoidal expression in transgenic xenotransplants, and will also study the role of T-cell infiltrates in xenograft rejection.

Animals↗
PubMed2003

Can we expand the indications for liver transplantation among hepatocellular carcinoma patients with increased tumor size?

INTRODUCTION: Due to the scarcity of donors and the fact that size is the main prognostic factor, Milan criteria have been used since 1996 to select hepatocellular carcinoma (HCC) patients for liver transplantation. In 2001 UCSF criteria showed that including layer tumors did not reduce the survival results. The objective of this paper was to evaluate whether HCC tumor sizes exceeding the Milan criteria adversely influence survival rates. PATIENTS AND METHODS: Between May 1988 and July 2001, 53 patients were transplanted due to HCC and cirrhosis. The etiology of cirrhosis was HCV in 23 cases and HBV in 6. In 11 cases the HCC were incidental by discovered namely, a mean/ diameter of 1.8 cm (versus 2.6 cm in nonincidental HCC). Sixty-two percent of tumors met the Milan criteria, and 68% the USCF criteria. RESULTS: The actuarial survival was 79% at 1 year and 62% at 5 years. The survival of patients with incidental HCC was 82% at 1 year and 82% at 5 years, which is better than the survival of those with nonincidental HCC (78% at 1 year and 57% at 5 years, P<.05). According to Milan criteria, the survival patients with early tumors was 82% at 1 year and 68% at 5 years, and for advanced tumors (NS), 75% and 54%, respectively. Comparison of early versus advanced tumors according to UCSF criteria showed survivals of 84% versus 64% at 1 year (P<.05) and 67% versus 48% at 5 years (P<.05), respectively. CONCLUSION: Increasing the HCC size among LT according to the California criteria did not reduce survival rates compared with the Milan criteria.

Alcoholism↗
PubMed2002

Selenium in a Wyoming grassland community receiving wastewater from an in situ uranium mine.

Water, soil, vegetation, grasshoppers, bird eggs, and bird livers collected at a 23.5-ha (58 acres) grassland irrigated with wastewater from an in situ uranium mine (study area) and a reference site in 1998 were analyzed for selenium and other trace elements. Selenium concentrations in the uranium mine wastewater applied onto the grassland ranged from 340 to 450 microg/L. Selenium in the upper 15 cm (6 in) of soil from the irrigated grassland at the mine ranged from 2.6 to 4.2 microg/g dry weight (DW). Mean selenium concentrations in soil and water were 5 and 15 times higher at the study area than at the reference site. Selenium concentrations in grasses and grasshoppers ranged from 6.8 to 24 microg/g and 11 to 20 microg/g DW, respectively. Selenium in red-winged blackbird eggs and livers collected from the study area ranged from 13.2 to 22 microg/g and 33 to 53 microg/g DW, respectively, and concentrations were well in excess of toxic thresholds. Mean selenium concentrations in grasses, grasshoppers, and bird eggs and livers were 5.8 to 30 times higher at the study area than at the reference site. Elevated selenium concentrations in water, soil, grasshoppers, and red-winged blackbird eggs and livers collected from the study area demonstrate that selenium is being mobilized and is bioaccumulating in the food chain.

Animals↗