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Biomedical subjects

J Mora

Publications and source records attributed to J Mora.

At least 55 records · Page 3Linked to original sources
PubMed2000

Spontaneous remission of congenital acute nonlymphoblastic leukemia with normal karyotype in twins.

BACKGROUND: Congenital acute nonlymphoblastic leukemia (cANLL) is an extremely rare event and represents only 0.5-1% of the leukemias in the first year of life. It is usually more common among patients with chromosomal abnormalities. Transient myeloproliferative disease (TMD) is an hyperleukocytosis entity that occurs almost exclusively in Down syndrome patients and remits spontaneously. Spontaneous remission of congenital leukemia has been reported and related to the presence of an extra chromosome 21. PROCEDURE: A pair of non-Down syndrome newborn twins presented with a clinical picture of skin rash and hyperleukocytosis. Twin B had full-blown cANLL with bone marrow, peripheral blood, skin, CSF, and placental invasion. Twin A presented transient peripheral blood and skin involvement by the same type of blast cells. No cytotoxic therapy was given. With 2 years follow-up, they continue to do well. RESULTS: Histologic and immunophenotypical analysis of placentas, cord blood, skin, CSF, bone marrows, and peripheral blood revealed a consistent picture of intrautero cANLL in twin B, with transplacental invasion of twin A. Normal and blast cells were found to be karyotypically normal. Spontaneous remission occurred. CONCLUSIONS: cANLL with karyotypically normal blasts can develop a self-limited clinical course, which has resemblances to TMD.

Bone Marrow↗
PubMed2000

Laser-capture microdissected schwannian and neuroblastic cells in stage 4 neuroblastomas have the same genetic alterations.

BACKGROUND: Neuroblastoma (NB) is a heterogeneous tumor composed of mixed populations of neuroblastic, Schwannian, and gangliocytic cells. PROCEDURE: We examined the genetic lineage of Schwannian and neuroblastic cells in stage 4 NB using laser-capture microdissection (LCM) and allelic analysis of microsatellite markers of chromosomes 1p, 11q, and 14q. RESULTS: In 18 out of 19 cases, individual cell types exhibited the same allelotype. CONCLUSION: Our results provide evidence that the majority of Schwannian and neuroblastic cells in stage 4 NB are of neoplastic origin, and support the hypothesis of a tumor stem cell capable of development along multiple lineages.

Child↗
PubMed2000

Comparison of several spray chambers operating at very low liquid flow rates in inductively coupled plasma atomic emission spectrometry.

Four different spray chambers were evaluated in ICP-AES at very low liquid flow rates: a double-pass (Scott type), a conventional cyclonic, and two low-volume cyclonic-type spray chambers (i.e., Cinnabar and Genie). A glass concentric pneumatic micro nebulizer (Atom Mist) was used in conjunction with all four chambers. The liquid flow rate was varied from 10 to 160 microL min(-1). The conventional cyclonic spray chamber gave rise to coarser tertiary aerosols, higher analyte and solvent transport rates, higher sensitivity and lower limits of detection than the remaining ones. The low-volume spray chambers afforded analytical figures of merit similar to the double-pass one, despite their very different designs. However, these spray chambers exhibited shorter wash-out times. The matrix effects were significant only for the double-pass. This fact allowed the analysis of reference samples by employing aqueous standards at a minimum level of sample consumption. The recoveries obtained for the cyclonic spray chambers and several certified samples were close to 100%, being always lower in the case of the double-pass spray chamber.

Journal Article↗
PubMed2000

Prospective evaluation of the contribution of K-ras mutational analysis and CA 19.9 measurement to cytological diagnosis in patients with clinical suspicion of pancreatic cancer.

The aim of this study was to prospectively evaluate the diagnostic contribution of the detection of K-ras mutation and measurement of serum CA 19.9 concentrations to cytological diagnosis in patients with clinical suspicion of pancreatic cancer. These patients had either the presence or absence of a pancreatic mass as determined by imaging procedures. A total of 156 consecutive patients with clinical suspicion of pancreatic cancer or for confirmation and follow-up of their chronic pancreatitis disease were included: 84 patients presenting a pancreatic mass (group 1) and 72 patients without a pancreatic mass (group 2). K-ras mutations were detected by a restriction fragment length polymorphism/polymerase chain reaction (RFLP/PCR) method and CA 19.9 by an immunoluminometric assay. When a pancreatic mass was present, cytology offered a high sensitivity, but with a significant number of inconclusive results and K-ras mutational analysis offered a highly specific test. In the absence of a pancreatic mass, CA 19.9 (cut-off 100 U/ml) increased the sensitivity of the diagnosis by cytology and K-ras mutational analysis did not add significant information. Thus both tests contribute to the clinical decision process when pancreatic cancer is clinically suspected and the cytological report is not conclusive.

Adult↗
PubMed2000

Clinical categories of neuroblastoma are associated with different patterns of loss of heterozygosity on chromosome arm 1p.

Deletion of the short arm of chromosome 1 is frequently observed in neuroblastoma (NB). We performed loss of heterozygosity (LOH) analysis of 120 well characterized NB to better define specific regions of 1p loss and any association with clinical and biological prognostic features (DNA index, MYCN, age, and stage). All categories of disease were represented including 7 ganglioneuromas, 8 stage 4S, 33 local-regional (stages 1, 2, and 3), and 72 stage 4 NB according to the International Neuroblastoma Staging System. Patients were consistently treated with stage-appropriate protocols at a single institution. Sixteen highly informative, polymorphic loci mapping to chromosome 1 were evaluated using a sensitive, semi-automated, fluorescent detection system. Chromosome arm 1p deletions were detected in all categories of tumor except ganglioneuroma. Frequent LOH was detected at two separate regions of 1p and distinct patterns of losses were associated with individual clinical/biological categories. Clinically aggressive stage 4 tumors were predominantly diploid with extensive LOH frequently detected in the region of 1ptel to 1p35 (55%) and at 1p22 (56%). The shortest region of overlap for LOH at 1p36 was between D1S548 and D1S1592 and for 1p22 was between D1S1618 and D1S2766. Local-regional tumors were mostly hyperdiploid with short regions of loss primarily involving terminal regions of 1p36 (42%). Most spontaneously regressing stage 4S tumors (7/8) were hyperdiploid without loss of 1p36 or 1p22. These findings suggest that genes located on at least two separate regions of chromosome arm 1p play a significant role in the biology of NB and that distinct patterns of 1p LOH occur in individual clinical/biological categories.

Alleles↗
PubMed2000

Determination of metals in lubricating oils by flame atomic absorption spectrometry using a single-bore high-pressure pneumatic nebulizer.

The behaviour of a single-bore high-pressure pneumatic nebulizer (SBHPPN) as a tool for the analysis of lubricating oils by flame atomic absorption spectrometry (FAAS) was investigated. The effects of the sample oil content [from 10% to 100% (w/w) oil in 4-methylpentan-2-one, IBMK] and the carrier nature (IBMK and methanol) on the characteristics of the aerosols generated, on the analyte transport efficiency and on the analytical figures of merit in FAAS were studied. A pneumatic concentric nebulizer (PCN) was used for comparison. Increasing the oil content increases the viscosity of the sample. With the PCN this gives rise to coarser aerosols, making it impossible to nebulize samples with an oil content higher than 70% (w/w). Using the SBHPPN, the viscosity of the sample scarcely affects the characteristics of the primary aerosols. Hence, the SBHPPN is able, by using the appropriate carrier, to nebulize pure lubricating oils. Among the carriers tested, IBMK is the most advisable because it is fully miscible with all the oil samples. The SBHPPN provides higher sensitivities and lower limits of detection than the PCN. Compared with a method based on organic dilution, the use of the SBHPPN for the direct analysis of lubricating oils by FAAS makes it possible, in addition to increasing the analysis throughput, to detect elements at lower concentrations. Moreover, the SBHPPN provides similar results to those obtained using a previous acid digestion step.

Journal Article↗
PubMed2000

Natural history of clinically compensated hepatitis C virus-related graft cirrhosis after liver transplantation.

The natural history of clinically compensated hepatitis C virus (HCV) cirrhosis after liver transplantation is unknown. This information is relevant to transplant centers to improve the management of these patients and decide the optimal timing for retransplantation. The aims of the study were (1) to describe the natural history of patients with HCV-cirrhosis transplants in a center with annual liver biopsies, and (2) to determine predictors for clinical decompensation, retransplantation, and mortality rates. A total of 49 patients with HCV-graft cirrhosis, 39 clinically compensated at histologic diagnosis of cirrhosis (post-liver transplantation cirrhosis) were included and followed up for 1 year (15 days-3.5 years). All patients tested were infected with genotype 1b. Predictive variables included histologic activity index (HAI) at post-liver transplantation cirrhosis, liver function tests, age, sex, and maintenance immunosuppression. Eighteen of 39 patients developed at least 1 episode of decompensation after a median of 7.8 months (4 days-2.6 years; 93% ascites). The cumulative probability of decompensation was 8%, 17%, and 42% at 1, 6, and 12 months, respectively. Graft and patient survival rates were 100%, 85%, and 71% and 100%, 92%, and 74% at 1, 6, and 12 months, respectively. Patient survival rates dropped significantly once decompensation developed (93%, 61%, and 41% at 1, 6, and 12 months, respectively). Variables associated with decompensation, retransplantation, and mortality rate included a high Child-Pugh score (>A), low levels of albumin at post-liver transplantation cirrhosis, and a short interval between liver transplantation and post-liver transplantation cirrhosis. The natural history of clinically compensated HCV-graft cirrhosis is shortened when compared with immunocompetent patients. If retransplantation is considered, it should be performed promptly once decompensation develops.

Adult↗
PubMed2000

Nutrition antioxidant status and oxidative stress in professional basketball players: effects of a three compound antioxidative supplement.

Professional basketball players of the First Spanish League (ACB) are highly trained athletes performing high training loads and competition sessions. As intense physical activity has been suggested to increase free radical production, we examined the effects of a vitamin antioxidant mixture on the degree of oxidative stress in these athletes. Subjects received either 600 mg alpha-tocopherol, 1,000 mg vitamin C and 32 mg beta-carotene, or a placebo over 32 days during a regular competition season. Plasma concentrations of alpha-tocopherol, vitamin C, beta-carotene, retinol, lipoperoxides (LPO), and the total antioxidant status (TAS) were analysed before and after treatment. Lipoperoxide plasma levels decreased significantly (p < 0.05) in the vitamin antioxidant supplemented group. The LPO/TAS ratio decreased about 15.3% in this group indicating a reduction in oxidative stress. Vitamin C dropped dramatically (p < 0.03, mean 15.4 micromol/L) in the placebo group leading to a marginal plasma vitamin C concentration (from 11 to less than 28 micromol/L). The results of this study suggest that the administered vitamin antioxidant mixture decreases oxidative stress and avoids the development of a marginal vitamin C status in professional basketball player during habitual training.

Adult↗
PubMed2000

Detection of dengue virus neutralizing antibodies in bats from Costa Rica and Ecuador.

Neutralizing antibodies for dengue virus serotypes 1 and 2 and serotypes 2 and 3 were detected in 1998 in 12 of 53 (22.6%) and 3 of 10 (30.0%) bats sampled in Costa Rica and Ecuador, respectively. Dengue is a consistent health problem in the two Costa Rican communities in which bats were sampled. The high percentage of bats with neutralizing antibodies to dengue virus in these two Costa Rican communities suggests that bats may become infected with dengue virus. This appears to be the case in Costa Rica and Ecuador.

Animals↗
PubMed2000

[ROC curve analysis of factors predictive of non-response to interferon treatment in patients with chronic hepatitis C, genotype 1].

The objectives of this study included: 1) to identify pretreatment variables predictive of absence of response in 107 patients with chronic hepatitis C, genotype 1, treated with interferon-a (IFN-a) at a dose of 3 MU three times weekly for 3-12 months and classified into two groups: group A, nonresponders vs. patients with a complete response, and group B, nonresponding and relapsing patients vs. patients with a sustained response; and 2) to establish a prognostic index using ROC curve analysis. The rate of sustained response was 6. 5% at the 24-month follow-up. The pretreatment characteristics with predictive value using ROC curves were as follows: in group A, age, GGT, serum ferritin, viral load, and grade and stage of the histological lesion; and in group B, known duration of infection, GPT, GGT, serum ferritin, viral load, and grade and stage of the histological lesion. In both group A and group B the positive predictive value (the probability of predicting an absence of response when the variable is present) was greater than the negative predictive value (mean: 84.3% vs. 41.1%, 99% vs. 16.5%, respectively). In group A, based on the prognostic index, the positive predictive value when three variables were present was 96% and the sensitivity was 63.5%, with the test being unequivocal in 6.5%, whereas when four or five variables were present, the positive predictive value was 97% and 100% and the sensitivity was 40.5% and 18%, respectively. In group B, the positive predictive value when two variables were present was 100% and the sensitivity was 87%, whereas when three, four, five and six variables were present the sensitivity was between 73% and 28%. In group A, age, GGT and ferritin were the predictive variables independently associated with an absence of response, with a relative risk of 6.5, 4.8 and 3.1, respectively, whereas in group B we did not find variables independently associated with an absence of response. It was concluded that in patients with genotype 1, it is possible to predict the absence of response to IFN therapy with a high degree of reliability.

Adolescent↗
PubMed2000

[ROC curve analysis of factors predictive of no response to interferon treatment in patients with chronic hepatitis C, genotype 1]

The objectives of this study included: 1) to identify pretreatment variables predictive of absence of response in 107 patients with chronic hepatitis C, genotype 1, treated with interferon-a (IFN-a) at a dose of 3 MU three times weekly for 3-12 months and classified into two groups: group A, nonresponders vs. patients with a complete response, and group B, nonresponding and relapsing patients vs. patients with a sustained response; and 2) to establish a prognostic index using ROC curve analysis. The rate of sustained response was 6.5% at the 24-month follow-up. The pretreatment characteristics with predictive value using ROC curves were as follows: in group A, age, GGT, serum ferritin, viral load, and grade and stage of the histological lesion; and in group B, known duration of infection, GPT, GGT, serum ferritin, viral load, and grade and stage of the histological lesion. In both group A and group B the positive predictive value (the probability of predicting an absence of response when the variable is present) was greater than the negative predictive value (mean: 84.3% vs. 41.1%, 99% vs. 16.5%, respectively). In group A, based on the prognostic index, the positive predictive value when three variables were present was 96% and the sensitivity was 63.5%, with the test being unequivocal in 6.5%, whereas when four or five variables were present, the positive predictive value was 97% and 100% and the sensitivity was 40.5% and 18%, respectively. In group B, the positive predictive value when two variables were present was 100% and the sensitivity was 87%, whereas when three, four, five and six variables were present the sensitivity was between 73% and 28%. In group A, age, GGT and ferritin were the predictive variables independently associated with an absence of response, with a relative risk of 6.5, 4.8 and 3.1, respectively, whereas in group B we did not find variables independently associated with an absence of response. It was concluded that in patients with genotype 1, it is possible to predict the absence of response to IFN therapy with a high degree of reliability.

Journal Article↗
PubMed1999

Primary epidural non-Hodgkin lymphoma: spinal cord compression syndrome as the initial form of presentation in childhood non-Hodgkin lymphoma.

BACKGROUND: Primary epidural non-Hodgkin lymphoma (NHL) is a rare but devastating event in pediatric oncology. Spinal cord compression due to an epidural mass from NHL, although it presents as a localized problem, in fact, is a systemic disease. Over the last 3 decades, aggressive systemic treatments with central nervous system prophylaxis have been designed with improving results. PROCEDURE: We reviewed the 20-year experience of the treatment of NHL with the LSA2-L2 protocol in our institution. Among 256 patients treated, five presented with primary epidural mass. Clinical features, treatment, and outcome of those five patients are presented. RESULTS: Three patients out of five responded favorably, and after a median follow-up of 10 years, they are cured. After presenting with paraplegia, functional and neurological recoveries were excellent. Of the patients who failed treatment, relapse occurred early, either during the treatment or right after completion of therapy. The relapses were within the central nervous system as well as systemic. CONCLUSIONS: Patients with primary epidural NHL presented with long histories of persistent back pain. Plain films of the spine were useless. All patients were diagnosed when neurologic damage had already been established. However, when the epidural NHL is treated aggressively with systemic chemotherapy and vigorous rehabilitation, the prognosis for complete neurological recovery and cure of the lymphoma is encouraging.

Adolescent↗
PubMed1999

Blood volumes and renal function in overt and subclinical primary hypothyroidism.

INTRODUCTION: Thyroid dysfunction is associated with marked alterations in cardiovascular and renal functions. In hypothyroidism, myocardial contractility, cardiac output, and oxygen consumption are decreased, whereas peripheral resistance is increased. METHODS: We assessed blood volumes and effective renal plasma blood flow (ERPF) and glomerular filtration rate (GFR) in 17 patients with overt primary hypothyroidism and in 15 of these patients when in euthyroid state after substitutive therapy. We performed the same measurements in eight patients with subclinical hypothyroidism. RESULTS: In the hypothyroid state, the plasma volume measured by dilution of 125I-albumin (APV) was higher than the calculated plasma volume (CPV) from packed red cell mass, suggesting an extravascular escape of albumin. After substitutive therapy, the CPV showed a statistical increase (P < 0.05), whereas APV remained unchanged. Both ERPF and GFR increased after thyroxine therapy (p < 0.05). In the subclinical group, blood volumes and renal function were similar to those found in the other group of patients when in the euthyroid state. CONCLUSIONS: We conclude that in primary hypothyroidism, ERPF and GFR are low, but that these values improve with substitutive therapy. CPV is a better index of the current plasma volume than APV. The difference between these two parameters suggests that the escape of albumin into the extravascular space in primary hypothyroidism is terminated by treatment. There are no clear abnormalities either in blood volumes or in renal function in subclinical hypothyroidism.

Adolescent↗
PubMed1999

The usefulness of Tc-99m tetrofosmin scintigraphy in the diagnosis and localization of hyperfunctioning parathyroid glands.

PURPOSE: The aim of the work was to study the diagnostic value of Tc-99m tetrofosmin to localize anomalous parathyroid glands in patients with hyperparathyroid disease. METHODS: We studied 31 patients, 19 with primary and 12 with secondary hyperparathyroid disease. Five of these patients were renal graft recipients. All patients underwent surgery. Each patient was injected with 555 to 740 MBq (15 to 20 mCi) Tc-99m tetrofosmin. Subsequently, radionuclide images were acquired 15 and 120 minutes after injection using a low-energy, all-purpose, parallel-hole collimator. Pertechnetate thyroid scintigraphy was obtained in nine cases (24 to 48 h later) when the thyroid activity made it difficult to identify the parathyroid glands. RESULTS: All cases showed tracer uptake as early as 15 minutes after injection. In the group of patients with primary hyperparathyroid disease, 15 showed focal uptake in a parathyroid gland, and surgery revealed an adenoma in the same location. In one patient with hyperplasia, scintigraphy identified only two of four diseased glands. In the three remaining cases, scintigraphy showed focal uptake in the lower parathyroid gland, whereas at surgery the abnormal gland was located in the upper pole. In the secondary hyperparathyroidism group, seven patients showed diffuse tracer uptake in two or more glands, and histologic analysis confirmed hyperplasia in all of them. Five cases showed focal uptake, with three evaluated after surgery (uptake in the only remaining gland); one of them was a renal graft recipient, and the remaining patient had chronic renal failure and was receiving hemodialysis. CONCLUSIONS: Our results suggest that Tc-99m tetrofosmin may be a suitable tracer for preoperative detection and screening of anomalous parathyroid glands. The earlier images at 15 minutes were better than those at 120 minutes. Tc-99m tetrofosmin is cleared more slowly from the normal thyroid than is Tc-99m sestamibi, and both of these tracers may give better results than the old pertechnetate TI-201 subtraction technique.

Adenoma↗