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Biomedical subjects

C Ridaura-Sanz

Publications and source records attributed to C Ridaura-Sanz.

At least 19 recordsLinked to original sources
PubMed2003

Desmoplastic hairless hypopigmented naevus: a variant of giant congenital melanocytic naevus.

Desmoplasia has been described in melanoma and Spitz naevus but not in giant congenital melanocytic naevus (GCMN). In melanoma desmoplasia is associated with a better survival. Four paediatric patients with hard, ligneous, progressively hypopigmented and alopecic GCMN were seen among 143 cases of GCMN at the Department of Dermatology of the National Institute of Paediatrics, Mexico City. Clinically, induration was progressive in three patients and regressive in one. Pigmentation was regressive in all. Histopathologically, all four patients showed intense dermal fibrosis, scarce naevus cells, and hypotrophic or absent hair follicles. Follow-up and serial biopsies in three patients documented the progressive nature of fibrosis and naevus cell depletion. No evidence of malignant transformation was found. Naevus cell depletion resulted in pigment loss and may have reduced the risk of malignant transformation. Although the cause of fibrosis is unknown, the possibility of an immune reaction to naevus cells is postulated.

Child↗
PubMed2002

Scleroderma 'en coup de sabre' and progressive facial hemiatrophy. Is it possible to differentiate them?

The aim was to be able to evaluate the diagnosis of two diseases by a consensus of clinical opinion used in the Department of Dermatology of the National Institute of Paediatrics in Mexico City. To differentiate between scleroderma 'en coup de sabre' (SCS) and progressive facial hemiatrophy (PFH), colour slides of 13 patients diagnosed as SCS and nine as PFH were examined by two dermatologists and microscopic slides by two pathologists. In both cases, the slides were randomly presented and no clinical information was given. The clinical and histopathological findings were statistically compared with two-tailed tests and alpha = 0.05. Kappa coefficients were obtained to evaluate the concordance between dermatologists, pathologists, and in terms of the consensus diagnosis. The usefulness of photographic assessment is limited by the inability to palpate the consistency of lesions. The most important clinical feature that differentiated both conditions was cutaneous sclerosis present in eight of 13 patients with SCS and in none of the PFH patients (P < 0.005). Other clinical features more frequently found in SCS were cutaneous hyperpigmentation and alopecia. The more frequent clinical features in PFH were total hemifacial involvement and ocular changes. Statistically significant histopathological features were: connective tissue fibrosis present in all cases with SCS and two of nine patients with PFH (P < 0.0002); adnexal atrophy present in 11 of 13 patients with SCS, and in three of nine with PFH (P < 0.02), and mononuclear cell infiltrates in all patients with SCS cf. six with PFH (P < 0.05). Our results suggest that in most cases it is possible to differentiate SCS from PFH based on clinicopathological findings.

Adolescent↗
PubMed2001

Liver fibrocystic disease and polydactyly: proposal of a new syndrome.

Liver fibrocystic disease (LFCD), characterized by dilatation of the intrahepatic bile ducts and variable degree of fibrosis, can be present alone or as part of many syndromes, such as Bardet-Biedl syndrome (BBS), Meckel syndrome, Jeune asphyxiating thoracic dysplasia, and Fraser-Jequier-Chen syndrome. We report two cases of LFCD and polydactyly with features similar, but not diagnostic of, BBS. Patient 1 was an 18-month-old boy with mental retardation, polydactyly, chronic renal failure, convergent strabismus, and hepatic fibrosis. Patient 2 was a male neonate with LFCD and polydactyly. Their manifestations could not be diagnosed as any of the previous mentioned entities. Difficulties in the early diagnosis of BBS have been previously reported and this could explain the clinical variability and heterogeneity of manifestations at the time of diagnosis. On the other hand, the existence of liver abnormalities in association with BBS has been previously described, but is rare. Our patients' malformations might represent a new entity where autosomal recessive inheritance is probable, but other patterns cannot be ruled out.

Bardet-Biedl Syndrome↗
PubMed2001

Quantitative study of the infection in brain neurons in human rabies.

Rabies virus is a highly neuronotropic virus that causes encephalomyelitis. Rabies virus infection was studied in neurons in the brain of an 8-year-old girl that died of rabies in Mexico. The extent of the neuronal infection was evaluated quantitatively in neuronal cell types of the brain using histologic staining for Negri bodies and immunoperoxidase staining for rabies virus antigen in the same neurons. Quantitative image analysis was used to compare the amount of infection in five different neuronal cell types, which was expressed as a percentage of neuronal area. Purkinje cells and periaqueductal gray neurons showed the largest percentage area for both Negri bodies and signal for rabies virus antigen. In general, there was a good linear relationship between the area of Negri bodies and the area of signal for rabies virus antigen. Many neurons with rabies virus antigen did not have Negri bodies, however, and some neurons with large antigen signals, especially Purkinje cells and periaqueductal gray neurons, lacked Negri bodies. Formation of Negri bodies is likely influenced by factors that vary in different neuronal cell types.

Brain↗
PubMed1999

Extraneural organ involvement in human rabies.

Human rabies is a fatal encephalomyelitis. After the development of the central nervous system infection, there is centrifugal spread of the rabies virus to extraneural (systemic) organs. With histochemical staining and localization of rabies virus antigen (RVA) with immunoperoxidase staining, we have examined tissue sections of organs from 14 postmortem pediatric and adult cases of human rabies acquired in Mexico and the People's Republic of China. RVA was found in nerve plexuses in multiple organs, including the gastrointestinal tract. RVA was observed in muscle fibers of the heart, tongue, and larynx. RVA frequently was observed in the adrenal medulla with an associated inflammatory reaction. Minor salivary glands of the tongue contained RVA and major salivary glands showed RVA in plexuses, but not in either acini or ducts. Epithelial cells of the tongue and taste buds were occasionally infected. RVA was observed in hair follicles of the skin and rarely in pancreatic islets. The infection of extraneural organs was sometimes, but not always, associated with an inflammatory reaction. These findings indicate that centrifugal spread of rabies virus to extraneural organs occurs frequently in human rabies.

Adolescent↗
PubMed1995

A novel mitochondrial DNA point mutation associated with mitochondrial encephalocardiomyopathy.

A novel mitochondrial DNA (mtDNA) mutation at position nt 4320 in the tRNA(Ile) gene was associated with severe encephalopathy in a 7-month-old infant, who died of intractable hypertrophic cardiomyopathy. The mutation was present in heteroplasmic fashion (88%) in muscle and fulfills accepted criteria for pathogenicity. This is the fourth pathogenic mutation identified in this gene, which appears to be a "hotspot" for deleterious mutations affecting the heart. This report adds to the evidence of genetic heterogeneity in hypertrophic cardiomyopathies.

Base Sequence↗
PubMed1995

Characterization of a 5025 base pair mitochondrial DNA deletion in Kearns-Sayre syndrome.

We characterized a mitochondrial DNA deletion in a patient with Kearns-Sayre syndrome. Southern blot hybridization showed that 86 to 93% of the mitochondrial genome harbored a 5.0 kb deletion. The percentage of affected genomes is higher than in previously described cases. Direct sequencing of the breakpoint region revealed that the deletion extended 5025 bp from nt 10,050 in the tRNA Gly gene to nt 15,076 in the cytochrome b gene, thus 30% of the total mitochondrial genome was lost by this deletion. A pair of extremely short mirror sequences flanking the mitochondrial DNA breakpoints were identified. These flanking sequences differ from previously published consensus 'hot-spots', known to give rise to deletions in human mitochondrial DNA.

Adolescent↗
PubMed1994

The pathologist's approach to the diagnosis of metabolic disease.

Many inborn errors of metabolism have tissue changes that suggest or indicate a diagnosis on morphologic bases. This emphasizes the involvement of the pathologist in the study of tissues obtained by biopsy as part of the diagnostic workup of cases with clinical evidence suggesting a metabolic disorder. Some of these diseases involve proteins with enzymatic activity with a consequent backlog of precursor metabolites. If these metabolites are insoluble or compartmentalized in cells, they accumulate in tissues. The diagnosis in those cases rests on establishing the nature of the accumulated materials and their topographic distribution. In some storage diseases, the abnormal substance can be identified in the affected tissues by histochemistry or ultrastructure. Another group of inborn disorders of metabolism produce changes in subcellular organelles such as peroxisomes and mitochondria. A third group is expressed by rather unique tissue changes which strongly suggest the diagnosis of metabolic disease.

Biomarkers↗
PubMed1993

[Pharyngo-tonsillitis and necrosing submaxillary adenitis caused by Streptococcus pyogenes associated with toxic shock syndrome in children from Mexico City].

We report on six previously healthy children between nine months and nine years old, who suffered streptococcal faringoamigdalitis and cervical adenitis with scarlet fever and toxic shock syndrome; four of them died in a fulminant course and two survived. These patients behave similarly to others reported from United States of America, England and Australia, and in similar way these clinical entity could be due to bacterial pyrogenic exotoxins according to the clinical fulminant course.

Child↗
PubMed1992

[The VATER association].

The clinical, radiologic, and anatomic features of 53 patients with VATER association were reviewed. The vertebral, anorrectal, tracheoesophageal, radial, and renal congenital defects included in the association are similar to those described by other authors. In this report genital anomalies are very frequent and should be included as a diagnostic criteria for this association. Encephalic, facial, and cranial congenital defects are common and can affect prognosis; 17 patients have other malformations patterns, and they can belong to a different group of malformations.

Abnormalities, Multiple↗
PubMedDate not supplied

Histopathology of vascular lesions found in Kasabach-Merritt syndrome: review based on 13 cases.

We reviewed the histopathology of 13 cases of Kasabach-Merrit Syndrome (KMS). In 4 (31%) cases the predominant morphology was that of a tufted angioma (TA). Six (46%) cases were Kaposiform hemangioendotheliomas (KHE), and 3 (23%) cases showed an infantile (juvenile) hemangioma only. Immunostaining for CD34 and actin (HHF-35) was helpful in defining these types of hemangiomas. The TA was characterized by a proliferation of endothelial cells positive for CD34 with a minimal component of actin-positive cells. KHE showed a paucity of immunoreactive cells; only the luminal endothelial cells were positive for CD34. In three cases with the morphology of infantile hemangiomas, actin-positive cells outnumbered the CD34-positive cells. Our findings confirm the observation that the underlying vascular lesion in KMS is usually not an infantile hemangioma as was originally thought, but variants of hemangiomas such as TA and KHE (77% of 13 KMS cases). Infantile hemangioma was the phenotypic substrate of KMS in only 3 of 13 cases.

Actins↗
PubMedDate not supplied

Ependymomas in children: histologic and DNA-flow cytometric study.

Ependymoma, a common neoplasm in the central nervous system of children, expresses great variability of morphological appearances. Correlation with clinical behavior has been controversial in previous studies. In order to explore the potential value of DNA-flow cytometric analysis in predicting the clinical course of ependymomas in children, we studied 22 patients with this tumor, selected from two large pediatric institutions. In addition, a number of histologic features were reviewed, such as necrosis, mitoses, endothelial proliferation, cellularity, and pleomorphism. DNA analyses of paraffin-embedded tissue from these tumors showed 9 of 17 (53%) with DNA indexes less than 1.16 and 8 of 17 (47%) with DNA indexes above 1.16. Ten of 17 (59%) patients died, 2 (12%) were lost for follow-up, and 5 (29%) are alive. No statistical correlation was found between DNA index, outcome, and histology. In spite of the small sample size, our findings appear to support the general impression that ependymomas are morphologically highly variable tumors of potential aggressiveness without valuable prognostic histologic markers.

Brain Neoplasms↗