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Biomedical subjects

L Michaels

Publications and source records attributed to L Michaels.

179 records · Page 10Linked to original sources
PubMed1967

Lung changes in woodworkers.

Pathological changes were observed in the lungs of two workers who had been exposed to wood dust for many years. The cause of death in each case was unrelated to the lung condition. The histopathological changes in the lung were: (1) centrilobular fibrosis and emphysema, (2) the presence of intra-alveolar basophilic particles which had excited a histiocytic and foreign body reaction. Special studies of these bodies tended to confirm the suspicion that they were particles of wood dust. Studies have shown that woodworkers are in an environment heavily saturated with wood dust. The present study suggests that the wood dust is inhaled into the alveoli and may lead to changes in the lungs.

Adult↗
PubMed1967

Unilateral ischemia of the fused twin placenta: a manifestation of the twin transfusion syndrome?

Two cases of multiple births were observed in which a twin placenta showed a striking gross and microscopic ischemia of one of its fused components. In both cases death of one or more of the infants occurred. Case 1 was a triplet birth of identical siblings and two of the infants died on the second and third days after birth, respectively. Case 2 was a twin birth in which one of the infants was stillborn. Two other cases are quoted from the literature in which a similar pallor of one-half of the twin placenta was observed, and both these cases were also associated with death of the associated fetus.It is possible that this placental lesion may be due to transfusion of blood from one placental half to the other (twin transfusion syndrome) with harmful effects on one or both fetuses.

Adult↗
PubMedDate not supplied

Computed tomography of the larynx: a clinical and pathologic study.

Recent interest in the application of computed tomography (CT) to the evaluation of laryngeal tumors, and the fact that the larynx offers the unique opportunity of whole organ study after total laryngectomy, led to a prospective study of laryngoscopy, conventional tomography, and CT in relation to pathologic findings. The results showed that CT gives an exact assessment of laryngeal anatomy and tumor involvement, particularly in the paracordal and pre-epiglottic spaces. The laryngeal cartilages, which are not well demonstrated by any other means, are accurately delineated by CT. There is also good demonstration of the laryngeal surface of the epiglottis, including the anterior commissure, which is poorly shown by other radiologic methods and is sometimes poorly seen on laryngoscopy. Because CT and conventional tomography present images at 2 different planes, at right angles to each other, we believe that CT is entirely complementary to conventional tomography.

Adult↗
PubMedDate not supplied

Cytochrome P-450 gene expression in the functional units of the fetal liver.

Hepatocytes of the right and left lobes of the fetal liver are surrounded by different microenvironments. The right and left lobes of the fetal liver are perfused by vascular systems carrying different concentrations of oxygen and constitute distinct functional units. The aim of this study was to assess the expression of the phenobarbital-inducible cytochrome P-450 b,e genes in hepatocytes of the right and left fetal liver lobes in mice. Northern-blot analysis using [32P]cDNAs and quantitative dot-blot hybridization were performed to assess the size and levels of these mRNAs in the right and left fetal liver lobes. In fetal mice, the levels of cytochrome P-450, b,e mRNAs were higher in the left than in the right fetal liver lobe. During the last days of gestation and in the immediate postnatal period, the levels of liver cytochrome P-450 b,e mRNAs increased predominantly in the left liver lobe. In contrast, the levels of albumin and alpha-fetoprotein mRNAs (genes studied to assess the specificity of these findings) were similar in each of functional units of the fetal liver. Phenobarbital induction of cytochromes P-450 b,e mRNAs was not observed in either of the fetal liver lobes. Postnatally, phenobarbital induced these cytochromes similarly in the right and left liver lobes. Therefore, the microenvironment surrounding fetal hepatocytes seems to influence the expression of the cytochrome P-450 b,e genes. This lobar heterogeneity of expression disappears as the pattern of adult liver circulation is attained.

Animals↗
PubMedDate not supplied

The common cavity congenital deformity of the inner ear. An important precursor of meningitis described in 1838.

Congenital deformity of the osseous labyrinth of the inner ear is well recognized as being associated with a fistulous communication with the intracranial subarachnoid space in some cases, leading to meningitis or a spontaneous 'stapes gusher'. Such cases have been described inappropriately as 'Mondini's dysplasia'. We cite 2 patients who both died of meningitis and had an accurate postmortem anatomical appraisal of the deformed temporal bones, one recently described by us and one by Cock more than 150 years ago. The use of eponyms is to be deprecated but should faithfully reflect the original description. The 'common cavity' lesion of the inner ear is a most important precursor of otogenic meningitis readily assessed by computed tomography and needing surgery to prevent the egress of cerebrospinal fluid or ingress of pathogens causing meningitis.

Child↗
PubMedDate not supplied

Statistical correlations among supraglottic cancers.

The purpose of this study was to quantify the extent to which the presence or absence of cancer in endoscopically evaluable regions of the supraglottic larynx predicted occurrence in a region less easy to visualize but of critical importance to the nature of treatment. Histologic findings from 32 specimens were subjected to two separate statistical analyses. In the first analysis, the presence of cancer on the floor of the ventricle was the best predictor of tumor below this level. The combination of variables with the best correlation was cancer on the floor of the ventricle and in the vestibular folds. In the second analysis, involvements of the deep structures in the aryepiglottic folds and in the infrahyoid epiglottis were the only significant predictors of tumor extending to the preepiglottic space. The results suggest that such statistical analyses may provide guidelines for selection of treatment.

Glottis↗
PubMedDate not supplied

The tunica propria in rhinoscleroma. An electron microscopic study.

The ultrastructure in 15 cases of scleroma was studied. The vacuoles of the Mikulicz cells had a definite limiting membrane containing two types of granular material, "A" considered to be antibody, and "B" considered antigenic. Inside the vacuoles infrequent beaded filamentous crystalloid structures were seen, probably of a proteinaceous nature. An enzymatic etiology causing disruption of the limiting vacuolar membrane was considered. New ultrastructural characteristics of the 'early' Mikulicz cell are described. The capillaries occasionally showed subendothelial amyloid deposition. The seromucinous glands were infrequent but of normal character.

Adolescent↗