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Biomedical subjects

R Newman

Publications and source records attributed to R Newman.

At least 91 records · Page 5Linked to original sources
PubMed1988

Cine magnetic resonance imaging for evaluation of congenital heart disease: role in pediatric cardiology compared with echocardiography and angiography.

Cine magnetic resonance imaging was used for preoperative and postoperative evaluation of 91 patients with congenital heart disease. Their ages ranged from 6 weeks to 14 years. The quality of study was excellent in 81% of the cases, in which it provided complete documentation of diagnostic features; substantial diagnostic information was provided in another 14%, and the study was nondiagnostic in only 5%. This technique was most useful for evaluating areas of the right ventricle (95%), great arteries (95%), vena cava (94%), and pulmonary venous system (91%). The anatomic delineation of these areas was comparable to that obtained by cineangiography and was superior to echocardiography, especially in postoperative patients. For complex venous anomalies, magnetic resonance imaging provided better anatomic details than did angiography or echocardiography. The capability of multiplanar imaging allows complex angled views through the desired planes of the heart and great vessels. Proper sedation is essential to obtain maximum diagnostic information. Our preliminary experience suggests that this new modality provides excellent anatomic information in infants and children with congenital cardiac defects and will play an increasing role in pediatric cardiac diagnosis.

Adolescent↗
PubMed1987

Physical and genetic analysis of cosmids from the vicinity of the cystic fibrosis locus.

Cosmid libraries have been constructed from DNA of somatic cell hybrid cell lines, each containing a fragment of human chromosome seven and including sequences closely linked to cystic fibrosis (CF). Cosmids containing human DNA as insert were isolated from the library. Three cosmids, when used as probes to total genomic DNA, detected polymorphic loci, each of which was shown to be in strong linkage disequilibrium with CF. Restriction endonuclease digestion of cosmid clones and use of a new, rapid method of chromosome walking based on competitive hybridisation of cosmid inserts has allowed identification of several groups of overlapping cosmids ("contigs") from the vicinity of CF.

Animals↗
PubMed1987

Clinical importance of myeloid antigen expression in adult acute lymphoblastic leukemia.

To determine the clinical importance of immunophenotypes in adult acute lymphoblastic leukemia (ALL), we prospectively studied 76 patients with this condition. Before treatment, lymphoblasts were tested for reactivity with monoclonal antibodies to B-cell, T-cell, and myeloid (My) antigens. Unexpectedly, myeloid antigens (MCS-2 or MY9) were identified in 25 patients (33 percent), usually in conjunction with B-cell or T-cell antigens. Among My+ patients, 15 (60 percent) expressed B-cell antigens (B+T-My+); all 6 tested had rearranged immunoglobulin genes. Five patients (20 percent) expressed T-cell antigens (B-T+My+), and one My+ patient expressed both B-cell and T-cell antigens. Only myeloid antigens (B-T-My+) were expressed in four patients (16 percent); three who were tested had germ-line immunoglobulin and T-cell-receptor gene configurations. Although no significant differences in presenting clinical features were found, My+ patients had fewer complete remissions than My- patients (35 vs. 76 percent, P less than 0.01). No differences in response or survival were observed between My+ and My- patients expressing T-cell antigens. However, among those expressing B-cell antigens, My+ patients had fewer complete remissions (29 vs. 71 percent, P = 0.02) and shorter survival (P = 0.03; median, 8.1 vs. greater than 26 months). These findings indicate that expression of myeloid antigen identifies a high-risk group of patients with adult ALL for whom alternative forms of treatment should be investigated.

Adult↗
PubMed1987

Structural changes in the haemagglutinin which accompany egg adaptation of an influenza A(H1N1) virus.

Antigenic changes are often induced in the haemagglutinin (HA) of human isolates of influenza A(H1N1) and B viruses during their isolation and propagation in embryonated hens' eggs. In this report we describe molecular changes in the HA of an A(H1N1) virus which accompany egg adaptation. The HA1 amino acid substitutions of egg-adapted variants are located in the vicinity of the receptor binding site. This suggests that egg-adapted variants are selected on the basis of altered receptor site specificity with concomitant effects on the antigenic configuration of the HA molecule. In this study, at least three antigenically distinct groups of egg-adapted variants were observed. These observations have implications for the indiscriminate use of egg-adapted viruses in sero-epidemiological studies and vaccine production.

Animals↗
PubMed1987

Pathologic effects of ESWL on canine renal tissue.

The introduction of extracorporeal shock wave lithotripsy (ESWL) has provided an avenue for dealing with many urinary stones noninvasively. The margin of safety for the kidney during shock wave administration is largely undefined. A pilot study was performed where six kidneys in five female mongrel dogs were shocked. Group A kidneys were given 1,776, 4,500, 6,000, or 8,000 shocks, respectively, at 18-24 kV. Group B kidneys received 1,600 and 8,000 shocks (18-24 kV). The number of shocks per electrode ranged from 500 to 4,538 and averaged 2,490. The dogs were sacrificed forty-eight to seventy-two hours (Group A) or twenty-eight to thirty-two days (Group B) post-treatment. Modest damage (hematoma and/or interstitial hemorrhage) was noted in all kidneys. Evidence of permanent change (fibrosis) was noted in both Group B kidneys. Complete necrosis of the kidney was not seen after administration of 8,000 shocks. These preliminary data indicate that lithotripsy can, in some circumstances, produce renal damage in the canine model.

Animals↗
PubMed1987

Optimal conditions for the induction of human mononuclear leukocytes by complexed polyinosinic-polycytidylic acid.

We have defined the optimal circumstances for the induction of human interferon alpha (Hu IFN alpha) in peripheral blood mononuclear cells (PBMC) using complexed polyinosinic-polycytidylic acids (poly rIrC). We have found that a poly rIrC concentration of only 0.1 microgram m/ml or 100 fold less than commonly used in fibroblasts produced maximal yields. Similarly, we have found that the optimal concentration of DEAE-D was 250 micrograms m/ml. Only a minimum exposure period of 30 minutes to the poly rIrC-DEAE-D mixture was found necessary, but the temperature of this incubation was not found to be a critical variant. Finally, we found that addition of exogenous calcium to the inducing solution failed to influence the ultimate titers of the IFN produced.

Calcium↗
PubMed1986

Silica and oesophageal cancer.

The growth of animal cells in culture can be stimulated very powerfully when they are allowed to extend upon a solid surface. In normal fibroblasts, the maximum is reached either on a plane surface with an area of 2500 micron 2 or on a narrow fibre with a length of 250 micron. This growth-stimulating effect of fibres could help to explain how asbestos causes cancer. All asbestiform minerals are complex mixtures of different lengths, but siliceous macrohairs with a uniform length are borne by several species of the grass genus Phalaris. Some of these species are common contaminants of the bread eaten in a part of Iran where oesophageal cancer has an unexplained high incidence. A pure preparation of 200 micron silica fibres from one of these species is a powerful promoter of cancer in the skin of mice. Similar fibres from millet (Seteria italica) are associated with the same disease in China, and plant silica has long been known to be associated the it in South Africa. In addition, a rare thoracic tumour, which normally only occurs after exposure to asbestos, has been detected among sugarcane farmers in the United States and in India; fine silica fibres are liberated into the air during the harvest.

Animals↗
PubMed1986

Biochemical and antigenic analysis using monoclonal antibodies of a series of of influenza A (H3N2) and (H1N1) virus reassortants.

Reassortant influenza A viruses with high growth capacity in eggs and suitable as candidate vaccine strains or as standard reagents for influenza HA quantification were prepared using the high yielding A/PR/8/34 (H1N1) as one parent and a number of 'wild' strains of influenza A (H1N1) or (H3N2) viruses as the other parent. The genetic and antigenic composition of the reassortants was determined. The parental derivation of genes in the reassortants was established by electrophoretic analysis of virus RNA and virus induced polypeptides. The haemagglutinin (HA) antigens of the three H1N1 viruses (NIB-6, NIB-7 NIB-12) were found to resemble those of the parental viruses when tested against a panel of monoclonal antibodies and using the HI test. A similar correspondence between the antigenic characteristics of the HA of the influenza A (H3N2) reassortants (NIB-1, NIB-4, NIB-5, NIB-8 and NIB-11) and parental viruses was noted. Therefore laboratory manipulations to produce the reassortants did not result in the selection of significant antigenic variants.

Animals↗
PubMed1986

Association of biogenic silica with disease.

Certain plants contain structures consisting of biogenic silica. This form of silica has been implicated as a causative agent in the high esophageal cancer areas of southern Africa, northeast Iran, and northern China. A spicule shape of biogenic silica is known to act as a tumor promoter in the mouse skin model system. The observation that fine biogenic silica fibers are found in leaves of sugarcane may pose a hazard for cane workers; also, the discovery that bracken contains silica fibers could have implications for browsing cattle. This paper reviews and discusses the involvement of biogenic silica in disease.

Animals↗
PubMed1986

Epidemiology of infectious diseases transmitted by drinking water in developed countries.

Research on the epidemiology of infectious diseases attributable to drinking water, common in the US during the past 20 years at least, is not yet really widespread in France. The role played by water in the transmission of certain infectious agents was important in European countries during past centuries but at present the incidence of waterborne diseases can be considered as very low. The absence of well-established data is due to the difficulty in reporting correctly a few minor outbreaks in a situation of very low endemicity. After a survey of the reported outbreaks, this paper deals with risk assessment of waterborne diseases in developed countries as well as special problems linked with proving transmission via water and with the nature of the infectious agents, and the development of monitoring methods for increasing our knowledge of this epidemiology.

Communicable Diseases↗
PubMed1985

Alterations in the hemagglutinin associated with adaptation of influenza B virus to growth in eggs.

In 1943 Burnet reported on changes in the hemagglutinating properties of human influenza virus which occurred during adaptation of the virus to growth in chicken eggs. Only recently has direct evidence been presented that these changes affect the antigenic properties of the virus. Schild et al. (G. C. Schild, J. S. Oxford, J. C. deJong, and R. G. Webster (1983), Nature (London) 303, 706-709) demonstrated that egg adaptation of influenza B virus selects variants which are antigenically distinct from virus grown from the same source in mammalian cells. The molecular changes in the hemagglutinin (HA) of influenza B virus associated with adaptation to growth in eggs have now been identified. A specific glycosylation site at the distal tip of the HA of influenza B virus grown exclusively in mammalian cell culture is lost or altered during egg adaptation. Since the HA functions in adsorption of virus to cells, it is concluded that removal or modification of an oligosaccharide structure at this position is required for influenza B virus to attach to and infect the allantois cells of the egg and that this has important implications for the antigenic configuration of the molecule.

Amino Acid Sequence↗
PubMed1984

A scanning electron microscope study of the extraembryonic endoderm of the 8th-day mouse embryo.

Late primitive streak embryos were dissected to reveal the junction between the visceral (VE) and parietal (PE) extraembryonic endoderm. Scanning electron microscopy showed that the two cell types differ markedly in their surface morphology and intercellular organization: the VE cells have numerous apical microvilli and form part of a continuous epithelial layer, while the smoother PE cells are scattered individually over the surface of Reichert's membrane. One interpretation of the morphology of the junction between the two tissues is that visceral endoderm cells in this region are detaching from the epithelial layer, migrating on to Reichert's membrane and differentiating into parietal endoderm. Preparatory to this, the visceral endoderm cells in the junctional zone may undergo extensive reorganization of their surface membranes.

Animals↗
PubMed1984

Severity of Parkinson's disease and the dosage of bromocriptine.

In view of reports that low-dose bromocriptine (15 mg or less daily) therapy is effective in Parkinson's disease, we undertook a retrospective study of 79 patients with Parkinson's disease to evaluate factors that affect the optimal daily dose of bromocriptine in subjects whose intake of levodopa was decreased as bromocriptine was introduced. Doses of bromocriptine 15 mg or less daily were seldom therapeutic; doses of over 15 mg, up to 30 mg, were appropriate for patients with mild, early disease. Those with more severe symptoms of longer duration usually required larger doses. The optimal daily requirement of bromocriptine was correlated to the severity and duration of the illness, but not to the age of the patient.

Adult↗
PubMed1983

Receptor for transferrin may be a "target" structure for natural killer cells.

Human transferrin receptors detected by monoclonal antibody OKT9 appear to be well expressed on cell types known to provide sensitive targets for natural killer (NK) cells. The possibility that transferrin receptors are recognized by NK effector cells has been investigated by three series of experiments: (i) analysis of the correlation between sensitivity to natural killing and the proportion of transferrin receptor-positive cells in different cell lines, (ii) study of the relationship between levels of transferrin receptor expression in cell lines and their capacity to competitively inhibit recognition and killing of the target cell K562 by NK cells, and (iii) comparison of affinity-purified soluble proteolytic fragments of the transferrin receptor and HLA-A, -B molecules for their ability to inhibit the natural killing effect. The data indicate that the transferrin receptor can provide a "target" structure for NK cells. Because transferrin receptors are ubiquitously expressed on normal and malignant proliferating cells, these observations have interesting implications for the possible function of NK cells in vivo.

Antibodies, Monoclonal↗