Search PubMed⌕ Search

Biomedical subjects

L M Reid

Publications and source records attributed to L M Reid.

140 records · Page 8Linked to original sources
PubMed1979

Virus carrier state suppresses tumorigenicity of tumor cells in athymic (nude) mice.

Nude mice injected subcutaneously with normal uninfected BHK 21 cells or HeLa cells regularly develop large, rapidly-growing tumours at the subcutaneous site of inoculation. However, these same tumour cell lines when persistently infected with VSV or other enveloped RNA viruses are either rejected or form small nodules in nude mice. This rejection phenomenon probably involves some type of immunocyte since heavily-irradiated nude mice (500 rads) cannot reject persistently infected cells but develop large, rapidly-growing tumours which shed virus and defective interfering virus (DI) and which do not exhibit the lymphocytic infiltration observed in the nodules of unirradiated mice given persistently infected cells. Finally, it was possible to select a subline of BHK 21-VSV carrier cells which regularly produces large rapidly-growing tumours in normal unirradiated nude mice, although all these carrier cells express virus antigen and shed large amounts of mature infectious virus and DI both in vivo and in vitro.

Animals↗
PubMed1978

Lung biopsy in congenital heart disease: a morphometric approach to pulmonary vascular disease.

Fifty patients with congenital heart disease, ages 2 days-30 years (median 12 months) at cardiac surgery, underwent lung biopsy to assess pulmonary vascular disease (PVD). Twenty-six had ventricular septal defects (VSD), 17 d-transposition of the great arteries (D-TGA), and seven, defects of the atrioventricular canal (AVC). Quantitative morphologic data was correlated with hemodynamic data. Three new grades of PVD were observed. Abnormal extension of muscle into peripheral arteries (grade A) was found in all patients; all had increased pulmonary blood flow. In addition, 38 of 50 patients had an increase in percentage arterial wall thickness (grade B); this correlated with elevation in pulmonary artery (PA) pressure (r = 0.59). Another 10 of 50 patients had, in addition to A and B, a reduction in the number of small arteries (grade C); nine of 10 were patients with elevated PA resistance greater than 3.5 mu/m2 (P less than 0.005). All three patients with Heath-Edwards changes of grade III or worse also had grade C. Reduction in peripheral arterial number probably precedes obliterative PVD and may identify those patients in whom, despite corrective surgery, PVD will progress.

Adult↗
PubMed1977

Secretory cells.

Explore the source record for details and available documents.

Animals↗
PubMedDate not supplied

Effects of dexamethasone on albumin and collagen gene expression in primary cultures of adult rat hepatocytes.

To further our studies on collagen gene expression, we have evaluated the molecular basis for the finding that steroids decrease collagen synthesis in cultured hepatocytes. We studied the effects of dexamethasone on primary cultures of adult rat hepatocytes grown on tissue culture plastic in either serum-supplemented medium or a serum-free hormonally defined medium. Cells were plated and allowed to attach for 24 hr in a mixture of serum-supplemented medium + hormonally defined medium. Cultures were then fed every 24 hr for 4 days under 1 of 4 conditions: serum-supplemented medium, serum-supplemented medium + dexamethasone, hormonally defined medium or hormonally defined medium + dexamethasone. On the fifth day, RNA was extracted. Dexamethasone did not affect the amount of RNA isolated; nor did it influence the quantitative translation of the mRNA in the rabbit reticulocyte lysate mRNA-dependent system. Employing hybridization analysis, dexamethasone resulted in increased albumin mRNA content in hepatocytes grown in serum-supplemented medium but had no affect on hormonally defined medium, and decreased type I in collagen mRNA content in cells grown in either serum-supplemented medium or hormonally defined medium. In cells cultured in hormonally defined medium, the beta-actin and procollagen mRNA levels were lower than those in serum-supplemented medium, but albumin mRNA levels were higher, and in fact equivalent to those in vivo. beta-Actin mRNA levels were not affected by dexamethasone in either serum-supplemented medium or hormonally defined medium.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMedDate not supplied

Glycosaminoglycans and proteoglycans induce gap junction expression and restore transcription of tissue-specific mRNAs in primary liver cultures.

Normal rat hepatocytes maintained on tissue culture plastic and in serum-supplemented medium lose their gap junctions within 12 hr and expression of their tissue-specific functions within 24 to 72 hr. The gap junctions are lost via internalization and degradation, and the differentiated functions due to loss of synthesis and to rapid degradation of tissue-specific mRNAs. Near normal levels of tissue-specific mRNAs can be achieved by stabilization of the mRNAs but not by transcription (for most genes), if the cells are cultured in a serum-free, hormonally defined medium and on substrata of tissue culture plastic, fibronectin or laminin, or on various purified collagens. The hormonally defined medium also extends the life-span of the gap junctions to about 24 hr. Certain glycosaminoglycans, proteoglycans and anionic polysaccharides have proven to be potent inducers of gap junction expression and function, to increase abundance of tissue-specific mRNAs, and to lower abundance of common gene mRNAs, a level of gap junctions and a pattern of gene expression similar to that in vivo. Addition to the hormonally defined medium of 10 micrograms per ml of hyaluronates, dermatan sulfates, bovine lung heparan sulfate, chondroitin 4-sulfate or chondroitin 6-sulfate resulted in a weak response in induction of gap junctions (5 to 15% of the cells became dye and electrically coupled) and in gene expression. An intermediate response in gap junction expression (30 to 50% coupled cells) and in gene expression was observed with 50 to 100 micrograms per ml of heparins or hyaluronates.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Embryonic and early fetal development of human lung vasculature and its functional implications.

Recently, we have identified in the mouse three processes involved in the early development of pulmonary vasculature: angiogenesis for branching of central vessels, vasculogenesis (lakes in the mesenchyme) for peripheral vessels, and a lytic process to establish luminal connection between the two. We have established that these three processes also operate in the human by studying serial sections of human embryos and early fetuses. Vascular lakes of hematopoietic cells appear at stage 13, i.e., 4+ weeks gestational age (GA), the first intrapulmonary vascular structure to appear. At stage 20 (50.5 days GA), a venous network with luminal connections to central pulmonary veins (PV) is present. Airways have not yet reached these regions of lung. At its first intrapulmonary appearance, the pulmonary artery (PA) is small and thick walled: it runs with the airway but its branching is slower, so many peripheral airways are not accompanied by a PA branch. By contrast, the PV has a peripheral patent network well before the PA. In the pseudoglandular phase, airway branching continues, and the PA catches up so that small PA branches are found with all airways. Later in this phase small nonmuscular vessels lie in the mesenchyme close to airway epithelium. By the early canalicular phase and the age of viability, continuity between pulmonary artery and the peripheral capillary network must be established. In a 10-week fetus several structures suggesting a breakthrough site were seen. Air-blood barrier structure is first seen at 19 weeks. Thus in the lung, the PA and PV are dissociated in their timing and pattern of branching. Early veins are present diffusely through the mesenchyme and establish central luminal connection to the main pulmonary vein before airway or artery are present at this level.

Blood Vessels↗
PubMedDate not supplied

Computer-assisted, operator-interactive technique for calculating pulmonary arterial taper.

We have developed a computer-assisted, operator-interactive technique which performs fast, precise computations of pulmonary artery taper. Individual 35-mm cineframes from balloon-occlusion pulmonary arteriograms are digitized into a 640 X 480 matrix in 8-bit depth and loaded into a VAX 11/780 computer for analysis. After operator identification of the arterial segment, an automated process of caliber analysis is initiated. By fitting a cubic spline function to the densitometric profiles extracted from the arterial segment, serial arterial cross-sectional diameters are calculated from the mathematically-derived points along the fitted curves. Spurious profiles, caused by sectioning at bifurcations, can be overridden by an operator-interactive subroutine. Taper is derived from the slope of the least-squares fit of vessel caliber with respect to its distance along the arterial segment. Results obtained by calculations from the computer-assisted caliber measurements were compared with those obtained by hand-tracing the same vessel segments. Correlation between computer-traced inflection points and hand-traced taper was very significant (r = .96, n = 13, P less than 0.001).

Child, Preschool↗