Senile dementia of the Alzheimer type (AD) is a fatal encephalopathy of uncertain etiology. Whether the neurotoxin aluminum plays any role in the AD process in unknown. Here we report an increased amount of aluminum in a chromatin subcompartment, the micrococcal nuclease (MN; EC 3.1.31.1) accessible dinucleosome fraction, in neocortical nuclei isolated from 17 control and 21 AD-affected brains. At these MN-accessible loci we also observe an increase in H1 zero linker histone proteins, DNA-binding proteins which are thought to act as regulators of chromatin compaction. These data support the hypothesis that one deleterious effect of aluminum upon nuclear structure in AD-afflicted brain may be to condense brain chromatin nonrandomly through an interaction with H1 zero linker protein and thereby alter the ability of brain DNA to be effectively transcribed.

Adult↗

PubMedDate not supplied

MDM2/p53 protein expression in the development of colorectal adenocarcinoma.

The murine double minutes 2 (MDM2) oncoprotein inhibits p53-mediated tumor suppression. MDM2 has been shown to be overexpressed in sarcomas and more recently was implicated in the pathogenesis of carcinomas. The purpose of this study was to determine the expression pattern of MDM2 in adenomas and colorectal adenocarcinomas and decide whether there is a correlation between MDM2 and p53 protein status. Paraffin-embedded tissues from 52 colorectal cancer (CRC) specimens and their adjacent normal tissue (N-CRC) were studied. In addition, 56 sporadic adenomas were investigated for the immunohistochemical expression of MDM2 and p53 proteins. Immunoreactivity of p53 indicating p53 gene mutation (p53+) was significantly higher in CRC (44%) compared to adenomas (23.2%) (P <0.01). None of the N-CRC specimens expressed the immunoreactive p53 protein. MDM2 overexpression (MDM2+) was similar in adenomas (30.3%) and CRC (25%), but only 2 (3.8%) of 52 N-CRC specimens showed overexpression of MDM2. In most cases MDM2 expression was associated with negative p53 expression (wild-type p53) in both adenomas (r = 0.59, P <0.001) and CRC (r = 0.69, P <0. 0001). No correlation was found between MDM2, p53 expression, and either the histologic grade, nodal stage or morphology of the tumors. There is greater p53 mutation in CRC compared to adenomas and N-CRC. The data indicate that MDM2 is overexpressed in CRC and is significantly associated with wild-type p53 compared to N-CRC specimens from the same patient. The MDM2 expression pattern is similar in adenomas and CRC, which may suggest that MDM2 overexpression is an early event in the progression of CRC.

Adenocarcinoma↗

PubMedDate not supplied

The effect of vagotomy and hydrocortisone administration on pulmonary surfactant activity in adult albino rats.

The role of vagus and hydrocortisone in the regulation of lung surfactant was studied in adult albino rats. Dynamic surface tension and phospholipid content were measured in the lung wash for estimating surfactant activity. The results indicate that vagotomy significantly decreases the surfactant activity whereas hydrocortisone does not alter it. But when hydrocortisone was administered prior to vagotomy it could prevent the decrease in surfactant activity. Thus it is concluded the regulation of lung surfactant in the adult lung is mainly by vagus nerve and hydrocortisone as such has no role but in the absence of vagal regulation hydrocortisone could maintain normal lung surfactant activity.

Animals↗

PubMedDate not supplied

Study of lung surfactant activity in guinea pigs after vagotomy.

Vagotomy in guinea-pigs reduces the pulmonary surfactant activity. Unilateral vagotomy brings about a similar reduction in the lung on the same side. The findings indicate that surfactant reduction may be an important causative factor in the initiation of pulmonary edema in vagotomised guinea-pigs. It is suggested that surfactant synthesis or release may be affected by alterations in the pulmonary blood flow or removal of the effect of neuro-secretory fibres, following vagotomy.

Animals↗

PubMedDate not supplied

Diesel automobile exhaust anad lung surfactant activity in an experimental study, in rats.

It has been observed that the lung surfactant activity decreased after exposure of the animals to diesel automobile exhaust. This decreased lung surfactant activity could be an important factor in the pathogenesis of pulmonary oedema and collapse seen in our experiments.

Animals↗

PubMedDate not supplied

Alpha-mannosidosis. Report of a case with morphologic, cytologic and immunohistochemical considerations.

We report the histopathologic features of the knee bone and synovium and the cytologic features of the synovial fluid from a patient with alpha-mannosidosis. The synovium showed marked papillary hyperplasia with infiltration of foamy histiocytes containing periodic acid-Schiff-positive, diastase-resistant material. Severe degenerative changes were seen in the knee bone. The synovial fluid showed increased numbers of macrophages containing periodic acid-Schiff-positive, diastase-resistant material. The differential diagnostic considerations in the synovial fluid are also discussed.

Adult↗