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Biomedical subjects

M Green

Publications and source records attributed to M Green.

At least 595 records · Page 33Linked to original sources

Pediatric education and the care of the person.

Pediatric education is preeminently concerned with the care of the person--the child, the parent, and the physician. Such personalized care can no longer be taken for granted. In both its scientific and humanistic qualities, it is being threatened by nonselective cost cutting. These changes will not spare pediatric education. The public, greatly concerned about the humanistic character of today's physicians, needs to better understand that pediatric education is fully committed to being humanistically as well as scientifically responsive to the needs of the times. Pediatrics should be defined as the specialty of growth, development, and adaptation, with adaptation offering a bridge between the biomedical and the psychosocial aspects of child health. Pediatric education needs both long- and short-term views. Opportunities to explore new pediatric roles have become time limited. A national strategic plan for pediatric education is needed. Because it takes more than the residency years to become a seasoned pediatrician, academic departments have a shared responsibility with the American Academy of Pediatrics, at the national and chapter level, to jointly fashion effective and relevant continuing education experiences.

Adaptation, Psychological↗

Structure and assembly of the endoplasmic reticulum. Biosynthetic sorting of endoplasmic reticulum proteins.

We have studied the post-translational processing and the biosynthetic sorting of three protein components of murine endoplasmic reticulum (ER), ERp60, ERp72, and ERp99. In pulse-labeled MOPC-315 (where MOPC-315 represents mineral oil-induced plasmacytoma cells) plasmacytoma cells, no precursor forms of these proteins were detected and only ERp99 was sensitive to endoglycosidase H. The ERp99 oligosaccharide remained endoglycosidase H sensitive during a 3-h chase, and analysis by high performance liquid chromatography showed the predominant structure to be Man8GlcNAc2. We have used a sucrose gradient analysis of pulse-labeled MOPC-315 plasmacytoma cells in order to directly study the biosynthetic sorting of both glycosylated and nonglycosylated ERps and have found no strong evidence to suggest these proteins ever leave the endoplasmic reticulum. In spite of their common sorting pathway, these proteins differ in their membrane orientation. Both ERp60 and ERp72 are entirely protected by the endoplasmic reticulum membrane while ERp99 appears to have a large domain exposed on the cytoplasmic face of the endoplasmic reticulum.

Animals↗

Structure and assembly of the endoplasmic reticulum. The synthesis of three major endoplasmic reticulum proteins during lipopolysaccharide-induced differentiation of murine lymphocytes.

Monospecific rabbit antibodies have been prepared against ERp72, ERp99, and ERp60, major protein components of a detergent-solubilized extract of endoplasmic reticulum purified from mineral oil-induced plasmacytoma 315 tissue. When subcellular fractions of mineral oil-induced plasmacytoma 315 tissue were assayed by an immunoprecipitation procedure, all three endoplasmic reticulum proteins (ERps) were found to be enriched in the rough endoplasmic reticulum. In murine lymphoid cells, the three ERps represent two major structural classes of protein. Both ERp72 and ERp60 contain no endoglycosidase H-sensitive, N-linked oligosaccharides. On the other hand, ERp99 is glycoprotein containing, in all likelihood, one endoglycosidase H-sensitive oligosaccharide. Immunologically cross-reacting proteins of similar molecular weight have also been detected in other eukaryotic cell lines. The anti-ERp antibodies were used to quantitate the synthesis and accumulation of the three ERps in splenic lymphocytes cultured in the presence and absence of bacterial lipopolysaccharide (Escherichia coli serotype B5:055) (LPS). In the presence of LPS, lymphocytes differentiate from resting cells into actively secreting cells. The synthesis of ERp72 and ERp99 increased 3- and 10-fold, respectively, in response to LPS. The synthesis of ERp60 does not change significantly. The turnover rates for these three proteins are similar in both control and LPS-treated lymphocytes. As a result, membranes isolated from LPS-treated cells are enriched in ERp72 and ERp99.

Animals↗

An enzyme-linked immunoassay for the detection of antibodies to endoplasmic reticulum.

A simple, sensitive solid-phase assay for the detection of antibodies to endoplasmic reticulum is described. The assay is dependent upon the amount of antigen bound to the solid support and upon the amount of antibody bound to the support via the relevant antigen. The assay can be used to measure both polyclonal and monoclonal antibody to endoplasmic reticulum. It has been used to isolate several monoclonal antibodies which can recognize and precipitate specific proteins of the endoplasmic reticulum. In addition, it has been used to probe the membrane orientation of endoplasmic reticulum antigens.

Animals↗

Bone microstructure by collagenase etching.

A novel technique has been developed for microstructural studies of bone. The spatial organizations of the mineral and collagen fibres in bone have been a matter of discussion for some time, with numerous diverse observations arising from various preparative techniques. In this latest investigation details of the mineral structure are clearly revealed in the SEM by treating a cut and polished surface of bone with collagenase to remove the major organic component. This new procedure has minimal effect on the mineral and hence reveals microstructural detail which is far closer to that in vivo than in previous investigations. This paper concentrates on two aspects of the studies, namely the detailed morphology of the mineral component and the arrangement of the collagen fibres in the osteons of compact bone. Firstly, the mineral component is revealed as comprising 'crystallites' (approximately 20 nm diam.) which aggregate to form larger contiguous 'spheroidal particles' (approximately 100 nm diam.), which in turn form 'granules' (approximately 500 nm diam.). Secondly, the regions from which collagen fibres have been removed are clearly revealed, showing that within an osteon, alternating lamellae have collagen fibres oriented approximately parallel to and circumferential to the Haversian canal respectively.

Animals↗

Kinetic studies on the diaqua form of cis-platin and various nucleobases.

Kinetic studies on cis-[Pt(NH3)2(OH2)2]2+ and various nucleobases show that this ion reacts more quickly with guanosine than with adenosine, cytidine, and thymidine, and that a monophosphoric acid unit considerably enhances the rate of reaction of guanosine; the kinetic preference of 5'-GMP over 5'-AMP may point to a greater thermodynamic selectivity.

Adenosine Monophosphate↗

The role of anthracyclines in the treatment of gastric cancer.

Prior to 1974 gastric cancer was considered refractory to chemotherapy. Single agent 5-Fluorouracil, mitomycin, and the nitrosoureas produced modest response rates with no augmentation of survival as compared to historical controls. Combinations of these agents produced slight increases in survival. The addition of doxorubicin, which had no major impact as a single agent, to 5-Fluorouracil and mitomycin C in 1974 produced impressive response rates over 40%, although these early optimistic results were tempered in randomized multi-institutional trials. Nevertheless, median overall survivals appear to have increased with this regimen over historical controls, and the substitution of cisplatin or methyl-CCNU for mitomycin C in Phase II trials has produced equivalent results. Comparison with historical controls is problematic as it is unknown what role more aggressive surgery and supportive measures may have played in increasing survival. Encouraging results with combination therapy in advanced gastric cancer have suggested opportunities to employ combination chemotherapy as adjuvant therapy or together with radiation for locally advanced gastric cancer. The role of less cardiotoxic derivatives of doxorubicin remains to be more fully explored.

Antineoplastic Combined Chemotherapy Protocols↗

Count-based scintigraphic method to calculate ventricular volumes in children: in vitro and clinical validation.

A "phantom" was used to validate 1) estimates of different depths of a constant radioactivity source, and 2) the calculation of different volumes using a constant depth and different attenuation coefficients. Using data from this in vitro study, scintigraphic estimates of right ventricular volume and ejection fraction were compared with those obtained by cineangiography in 36 children with either a normal right ventricle or various right ventricular diseases. The static program accurately estimates the distance from the radiation source to the collimator surface (r = 0.99). Radionuclide count methods best predict "phantom" volumes using attenuation coefficients between 0.11(-1) and 0.13(-1) cm. A coefficient of 0.10(-1) underestimates, whereas 0.15(-1) cm grossly overestimates actual volumes. In vivo data were therefore analyzed using an attenuation coefficient of 0.11(-1) with right ventricular counts corrected using either right ventricular or left ventricular background. Closest agreement between scintigraphic and cineangiographic volumes was obtained using right ventricular background, although end-diastolic volumes larger than 100 ml were substantially underestimated. On the basis of this study, the use of two different attenuation coefficients is suggested: the smaller 0.11(-1) cm to calculate end-systolic and end-diastolic volumes and the larger 0.15(-1) cm for volumes greater than 100 ml.

Adolescent↗