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Biomedical subjects

A John

Publications and source records attributed to A John.

At least 91 records · Page 5Linked to original sources
PubMed1987

Blockade of the response to volume expansion by monoclonal antibodies against atrial natriuretic peptides.

It is known that plasma levels of atrial natriuretic peptides (ANP) increase in response to volume expansion. However, the extent to which these increased levels of ANP participate in the renal response to volume expansion remained unknown. This question can be answered with the aid of a monoclonal antibody that binds specifically to the biologically active forms of ANP: Ascitic fluid containing this monoclonal antibody dose-dependently and specifically blocks the natriuretic, diuretic and hypotensive effects of synthetic atriopeptin II given intravenously in rats. Volume expansion induced by injection of 20 ml/kg homologous blood in anaesthetized rats evokes massive diuresis and natriuresis. Pretreatment with ascitic fluid containing monoclonal antibody completely blocks this diuretic and natriuretic response during the first 20 min after volume expansion. Thus the initial renal response to volume expansion is due to the increase in endogenous ANP. Similar results were obtained for volume expansion with isotonic saline in conscious rats. It is supposed that the effects of ANP are mediated through particulate guanylate cyclase activation and intracellular cyclic guanosine-monophosphate (cGMP) accumulation in target tissues including renal and vascular smooth muscles cells. Besides increasing plasma ANP levels (measured by radioimmunoassay) volume expansion also induces an increase of cGMP levels both in plasma, urine and in renal tissue. This increase is ANP-dependent as it can be blocked by the monoclonal antibody.

Animals↗
PubMed1986

The use of a monoclonal antibody to measure plasma atriopeptins in rat.

A monoclonal antibody with specificity for atrial natriuretic peptides (ANP) was produced, that can be used for the radioimmunological determination of ANP-immunoreactivity (ANP-IR) in rat plasma. The antibody recognizes atriopeptin I, II, III, as well as alpha-hANP and alpha-hANP fragment (7-28) and does not crossreact with ANP-fragments (13-28) and (18-28). Plasma levels of ANP-IR in conscious Wistar rats were determined before and after volume-loading. Basal plasma levels of ANP-IR were 108 +/- 12 pg/ml, and after volume-loading increased to 800 +/- 59 pg/ml.

Animals↗
PubMed1986

Antigenic and molecular evolution of the vaccine strain of type 3 poliovirus during the period of excretion by a primary vaccinee.

A 4 month old child was immunized with a vaccine containing the Sabin live attenuated vaccine strains of all three serotypes of poliovirus. The antigenic and molecular evolution of the Sabin strain of poliovirus type 3 was then followed throughout the entire period of virus excretion. Novel strains appeared at 8, 42 and 52 days post-vaccination and were the products of both intertypic recombination between type 2 and type 3 poliovirus in regions of the genome coding for non-structural proteins and of point mutations in the region coding for the structural proteins. Excretion of virus continued for 73 days. All strains examined reacted with all monoclonal antibodies specific for the main immunodominant antigenic site of type 3 poliovirus, but variation was observed at other, immunorecessive sites. These findings have possible implications for the evolution of the virus in vaccinees or in epidemics and are consistent with the known antigenic stability of the virus.

Antibodies, Monoclonal↗
PubMed1984

Chylopericardium following aorto-coronary bypass-procedure.

The complication of chylopericardium following cardiac surgery is extremely rare. We report such a patient who had undergone a coronary artery bypass operation. The cause of chylopericardium in this patient appears to have been intraoperative injury to the tributaries of the thoracic duct. A conservative regimen with continuous drainage and a special diet containing medium chain triglycerides was all that was necessary for the management of this complication.

Chyle↗
PubMed1982

Genetic and antigenic variation in type 3 polioviruses: characterization of strains by monoclonal antibodies and T1 oligonucleotide mapping.

Considerable genetic and antigenic heterogeneity was detected among a collection of 17 poliovirus type 3 strains isolated between 1939 and 1958 in studies using monoclonal antibodies and by T1 oligonucleotide mapping. Heterogeneity was detected even amongst a collection of nine viruses designated Saukett and assumed to originate from the same prototype virus. The monoclonal antibodies were found to differ in their strain specificities for poliovirus type 3 strains in virus neutralization or single-radial-immunodiffusion tests. Relationships between strains detected in this way were in general consistent with those detected by oligonucleotide mapping. One of the monoclonal antibodies (NIBp 56) was able to distinguish between certain Saukett virus strains which differed by as little as a single specific oligonucleotide. The heterogeneity detected amongst Saukett viruses is of potential practical importance since these strains are used widely in the manufacture of inactivated poliovirus vaccine.

Antibodies, Monoclonal↗
PubMed1978

Interest in geriatrics at a university Department of Medicine.

To estimate available resources for teaching geriatrics to medical students, a survey of the members of a university Department of Medicine was undertaken. Information was elicited in six areas: 1) personal data, 2) characteristics of each physician's clinical practice, 3) potential interest in a Division of Geriatrics, 4) the comparative levels of aggressiveness indicated in the management of an old patient versus a young one, 5) the attitude of physicians toward the elderly, and 6) a rough measure of knowledge of the demographic characteristics of the elderly. The results suggest that a significant number of faculty members of a university medical school would indeed be interested in teaching and research in the field of geriatrics.

Adult↗
PubMedDate not supplied

Bed usage in a Dublin teaching hospital: a prospective audit.

AIMS AND METHODS: We prospectively audited inpatient bed use in our hospital for the first three months of this year. While 70% (mean age 54 +/- 20.8 years) of our patients went home on the day they were medically discharged, 30% (mean age 70.3 +/- 18.3 years) remained in the hospital awaiting step-down facilities. The total of 486 bed days occupied by overstaying patients would if available, have allowed treatment of 54% more patients without any increase in the hospital complement of beds, preventing the cancellation of elective procedures and preventing patients remaining on trolleys overnight. RESULTS AND CONCLUSION: These prospective data emphasise (1) a highly inefficient use of acute hospital beds; (2) the need for step-down facilities; (3) efficient use of existing hospital beds is the highest priority both for optimal patient care and optimal use of expensive hospital resources; (4) efficient use of existing facilities should be achieved before the construction of additional facilities.

Adult↗