Syndecan-1 (CD138) and Ki-67 expression in different subtypes of ameloblastomas.

Ameloblastoma is the most frequent odontogenic tumor and is considered a benign, but locally invasive, neoplasm with variable clinico-pathological expression. Syndecan-1 is a cell surface proteoglycan that binds cells to the extracellular matrix and its expression is down-regulated in many cellular transformation models. The aims of this study were to examine the pattern of syndecan-1 expression, to evaluate the proliferating activity in a large series of solid/multicystic (SA) and unicystic ameloblastomas (UA), and to study its possible correlation to their biological behavior. Immunohistochemical studies were performed for syndecan-1 (clone MI15) and Ki-67 (clone MIB-1) in 120 ameloblastomas (75 SA and 45 UA). The salient finding was that expression of syndecan-1 was related to the histological subtype of tumors, as there was a lower expression in SA (40.2%) as compared to UA (49.7%) (p<0.05). These findings did not correlate with Ki-67 expression, as this was similar in both types of ameloblastomas. Our results suggest that the reduced expression of syndecan-1 supports the view that SA has a more aggressive biological behavior than the UA. The lack of correlation between reduction of the syndecan-1 and Ki-67 index may be due to the different histomorphologies of both types of ameloblastoma, and more studies are necessary to better understand the role of this protein in the biological behavior of these tumors.

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.

Malignant melanoma in children and congenital melanocytic nevi: DNA content and cell cycle analysis by flow cytometry.

Malignant melanoma (MM) in children, although a rare neoplasm, can occur within a preexisting congenital melanocytic nevus (CMN). All the potential risk factors for this phenomenon are not well known, but increases in S phase and G2 + M phase of cell cycle, DNA aneuploidy, and cell cycle abnormalities in precursor lesions might be among the risk factors. Using paraffin-embedded tissue, we performed a retrospective analysis of DNA content, aneuploidy, and cell cycle by flow cytometry. Two groups of patients were analyzed: 28 children with CMN who did not developed MM, and 6 patients who further developed MM. In this second group, three patients had four biopsies done before the appearance of MM and in two patients biopsies were done after the appearance of MM. All CMN not associated with MM exhibited diploid cells only, their S phase was 11.5% (+/- 3.8), and their G2 + M phase was 2.5% (+/- 2.2). Among those patients who developed MM, 3/6 had an S phase > 15.5 and a G2 + M phase > 2.3 prior to the appearance of MM. Two out of six patients had a tetraploid DNA when MM developed and died with a disseminated MM. They had an S phase > 15.5 and their G2 + M phase was > 2.5. We propose that evaluation of DNA content and cell cycle by flow cytometry is a useful method to supplement biopsy findings in children with CMN who have lesions suspicious of developing a MM.

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.

[Causes of death in congenital hypothyroidism. An autopsy study]. / Las causas de muerte por hipotiroidismo congénito. Un estudio realizado en necropsias.

Children with congenital hypothyroidism are prone to die unexpectedly. In order to test this hypothesis, the primary and contributing causes of death were studied in a case series of sixteen consecutive children coming to autopsy. Four patients with absent thyroid died undiagnosed and untreated. The remaining twelve cases had documented hypothyroidism with low T3 and T4 levels. Diagnosis was established after the age of two months. Nine of the sixteen cases died unexpectedly, three while in the hospital and six at home. Autopsy findings suggested bronchoaspiration in five and heart failure in four. The remaining seven cases died under predictable circumstances with serious infections. Children with congenital hypothyroidism with delayed treatment may die unexpectedly as a result of the organic dysfunction caused by their primary disease.

[Prune belly syndrome associated with cystic adenomatoid malformation of the lung and pulmonary sequestration]. / Síndrome de "prune belly" asociado a malformación adenomatoide quística pulmonar y secuestro pulmonar.

The "prune belly" syndrome classically described in males, has also been described in female patients with a variable incidence. Associations with multiple respiratory tract malformations have been reported which together with urinary tract anomalies and renal failure are often the cause of early mortality. We report the case of a female patient with prune belly in association with cystic adenomatoid malformation of the lung and pulmonary sequestration with a favorable clinical evolution following medical and surgical treatment.

Sling left pulmonary artery, bridging bronchus, and associated anomalies.

Sling left pulmonary artery (SLPA) is often associated with tracheobronchial abnormalities, including bridging bronchus (BB). We report on 3 patients with SLPA: One patient had a narrow trachea, absent right upper lobe and right main bronchus, and BB. The second patient had a long and narrow trachea, with normal segmentation of bronchial tree, abnormal cerebral gyri, and minor facial abnormalities. The third patient, with a normal trachea and main bronchi with BB, had imperforate anus, hemivertebrae, and atrial septal defect (VATER association). Patients with SLPA, those with BB, or those with both SLPA and BB as well as multiple congenital anomalies represent a spectrum of anomalies.

[Primary amebic meningoencephalitis caused by Naegleria fowleri in an adolescent from Huetamo, Michoacan, Mexico]. / Meningoencefalitis amibiana primaria por Naegleria fowleri en un adolescente de Huetamo, Michoacán, México.

A 13 year old boy died after a three day illness with severe headache, explosive vomiting, fever and progressive loss of consciousness. The autopsy revealed purulent and necrotizing meningoencephalitis mainly involving the basal regions and posterior fossa and on microscopic examination numerous trophozoites of Naegleria were seen in the meninges and necrotic brain tissue. The trophozoites were identified as Naegleria fowleri by immunoperoxidase staining. This case as well as others previously reported in Mexico and the documented presence of Naegleria species from several sources indicate that primary amebic meningoencephalitis should be considered in the differential diagnosis of cases with neurological symptoms of sudden onset.

Osler-Weber-Rendu disease in an infant.

A 23-month-old girl with Osler-Weber-Rendu (OWR) disease manifested by hemoptysis died of massive pulmonary hemorrhage. Autopsy showed predominant respiratory tract involvement, but telangiectatic vessels were also present in other sites. Skin lesions were absent. A grandfather had died after bleeding by mouth following physical exertion. This disease seldom appears in children and hemorrhage usually manifests after 30 years of age.

Langerhans cell histiocytosis: clinical experience with 124 patients.

We cared for 124 pediatric patients with a histologic diagnosis of Langerhans' cell histiocytosis (histiocytosis X) over a period of 14 years. Clinical, laboratory, and radiographic findings were analyzed. The most frequent manifestations were bone lesions, lymph node involvement, and skin infiltration. Liver disease was noted in 50% of patients and lung disease in 23%; hematologic changes were also frequent. Dysfunction and involvement of these three organ systems, plus age of onset, distinguished the group of patients with the highest mortality. All patients with generalized disease or organ dysfunction were treated with systemic chemotherapy. The actuarial survival curve at 10 years was 63%.

Treatment of non-Hodgkin's lymphoma in Mexican children. The effectiveness of chemotherapy during malnutrition.

The histological diagnosis of non-Hodgkin's lymphoma (Burkitt's lymphoma excluded) in 147 children was reviewed. The most common site of presentation was in the abdomen (32.6%). The most frequent site of metastatic disease at diagnosis was the bone marrow (27.2%). The most common histology was diffuse undifferentiated non-Burkitt type (37.4%). According to the Murphy staging system, 40.1% were stage III and 27.2% were stage IV. In a nonrandomized prospective study, 121 patients were submitted to a treatment regimen (protocol 8001) and compared with 26 historical controls treated with the COP regimen, consisting of cyclophosphamide, vincristine, and prednisone. Of those patients treated with protocol 8001, nine had intestinal perforation at the site of primary disease. All patients in this group were malnourished at the time of perforation. The overall rate of initial complete remission in those patients treated with protocol 8001 was 90.7%. The duration of remission was from 16 to 108 months, with a median of 39 months. The actuarial rate of disease-free survival was 69% at 2 years and 63% at 6 years, compared with 36% at 6 years of the control group (COP) (p less than 0.01). None of the patients have relapsed after 4 years.

Primary amoebic meningoencephalitis in a young male from northwestern Mexico.

Primary meningoencephalitis caused by Naegleria fowleri was documented in a 16-year-old male from Mexicali in the state of Baja California in Mexico. In August 1978, seven days after sustaining moderate head trauma while swimming in a shallow, stagnant irrigation ditch on a hot summer day, the patient presented an acute illness with severe headache, fever and convulsions rapidly progressing into a comatose state. Actively moving trophozoites were observed in the spinal fluid on admission. The patient died shortly after admission to hospital on the third day of symptoms. Post-mortem examination revealed a meningoencephalitis with extensive destruction, haemorrhage and numerous parasites involving structures of the posterior fossa. Immunoperoxidase strains of trophozoites in meningeal and cerebellar tissue were positive for N. fowleri KUL and negative for N. gruberi, N. australiensis and Acanthamoeba rhysodes. This appears to be the first documented case of the disease in Mexico.