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Biomedical subjects

R Davis

Publications and source records attributed to R Davis.

At least 433 records · Page 24Linked to original sources
PubMed1979

Amrinone: a new non-glycosidic, non-adrenergic cardiotonic agent effective in the treatment of intractable myocardial failure in man.

Chronic congestive heart failure not controlled by conventional therapy was treated with intravenous amrinone, a new non-glycosidic, non-catecholamine cardiotonic agent. Eight patients with New York Heart Association functional class III-IV symptoms were hemodynamically monitored. At peak effect, cardiac index (CI) increased from 1.84 +/- 0.32 to 2.74 +/- 0.44 l/min/m2 (mean +/- SD) (p less than 0.001) and left ventricular filling pressure (LVFP) decreased from 25.8 +/- 6.2 to 19.5 +/- 6.8 mm Hg (p less than 0.05), while heart rate and mean aortic blood pressure did not change significantly. Mean endocardial circumferential fiber shortening (mean Vcf), determined by echocardiography, increased from 0.61 +/- 0.27 to 0.89 +/- 0.34 cir/sec (p less than 0.05). The duration of action after bolus infusion varied from 60--90 minutes. During continuous infusion of amrinone, sustained increases in CI and reductions in LVFP, similar to those at the time of peak effect after bolus administration, were maintained for 180 minutes. These marked cardiotonic effects of amrinone in patients already taking digitalis for severe heart failure occurred without side effects of arrhythmias or altered arterial pressures. The fact that the drug is orally active makes amrinone a v:ry promising inotropic agent for the treatment of chronic heart failure in man.

Aged↗
PubMed1979

Banked autologous blood for caesarian section.

Experience with the use of banked autologous blood in five patients undergoing elective caesarian section showed that two patients developed painless uterine contractions during phlebotomy, and a third delivered an infant who developed severe respiratory distress. The other two patients had no complications and delivered healthy infants. Caution is needed before recommending the use of this technique in obstetric practice.

Adult↗
PubMed1979

Applications of xeroradiography in dentistry-a review.

Xeroradiography is the technique in which electrostatically charged plates sensitive to X-rays are used in diagnostic radiology in place of conventional film. There has however been anxiety that radiation dosage for xeroradiography may be at unacceptably high levels. James et al., however, in 1973 showed that by increasing the kilovoltage to at least 120 the exposure could be reduced by 60 per cent. Using higher kV lateral oblique jaw and lateral and anteroposterior skull xeroradiographs have been produced with lower radiation exposure than conventional film. Bony detail is much more sharply delineated on xeroradiographs and soft tissues are visible on the same picture without use of a grid or wedge filter. These features are of obvious advantage in cephalometrics and orthognathic surgery. Panoramic techniques are potentially the most useful way of applying xeroradiography. The combination of full jaw coverage with the sharp definition only possible at present with intra-oral radiographs would provide more information for the dentist, save time for the radiographer and reduce the dose to the patient. Excellent results have been obtained with autopsy specimens on machines which develop 90kVp, but optimal exposure for a normal adult requires a panoramic X-ray machine development 120 kVp. Xeroradiography has the advantage, therefore, of providing more detail of diagnostic value with lower radiation exposure to the patient. The process requires no silver, which is in increasingly short supply.

Humans↗
PubMed1979

Black suicide in the seventies: current trends.

In the most recent decade, the suicide rate among young blacks has risen to the point where it is nearly as high as that of their white peers. The data in this analysis reflect the striking contrast in age distribution in the suicide patterns of whites and blacks. Whereas white suicide increases in direct relation with advancing chronological age, suicide among blacks reaches its peak in the youthful years. Current statistics fail to reflect a "dramatic" or significant increase in the suicide rate of black women. Contrary to popular belief, black men in their twenties represent the most suicide-prone group. Young black males have been committing suicide at a steadily increasing rate during the past six years. Regionally, black suicide rates are highest in the North and West and lowest in the South. White suicide rates reflect a slightly different regional distribution. The highest rates occur in the West and the lowest in the North.

Adolescent↗
PubMed1979

Soda lime dust.

Explore the source record for details and available documents.

Adult↗
PubMed1978

Electron microscope localization of acetylcholinesterase and butyrylcholinesterase in the superior cervical ganglion of the cat. I. Normal ganglion.

The distributions of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in the superior cervical ganglion (SCG) of the cat were determined by electron microscopy (EM) with the bis-(thioacetoxy)aurate (I), or Au(TA)2, method. Before the infusion of fixative, one of the enzymes was selectively, irreversibly inactivated in vivo, as confirmed by light microscope (LM) examination of sections of the stellate ganglion stained by the more specific copper thiocholine method. Physostigmine-treated controls, for inhibition of AChE or BuChE, were stained concomitantly with tissue for enzyme localization by the Au(TA)2 method for EM examination in each experiment. It was concluded that most of the AChE of the cat SCG is present in the plasma membranes of the preganglionic axons and their terminals, and in the dendritic and perikaryonal plasma membranes of the postsynaptic ganglion cells. BuChE is confined largely to the postsynaptic neuronal plasma membranes. Reasons for the discrepancies between the localizations found by the present direct EM observations and those deduced earlier from LM comparisons of normal and denervated SCG are discussed. It is proposed that a trophic factor released by the preganglionic terminals is probably required for the synthesis of postsynaptic neuronal AChE, and that BuChE may serve as a precursor of AChE at that site.

Acetylcholinesterase↗
PubMed1978

An image reversal process for electron microscope film.

An improved technique has been developed to produce a positive image directly on some standard electron microscope films (Kodak 4489, SO 163, and Ilford Electron Microscope Film). This technique has been useful for processing micrographs of freeze-etched and shadowed specimens, and eliminates the need for producing positive image transparencies before printing.

Bacillus thuringiensis↗
PubMed1978

Photochemical inhibition of poliovirus replication by 4,5',8-trimethylpsoralen plus light.

Poliovirus replication in HeLa cells is significantly inhibited by a 30-min pulse of infected cells with 4,5',8-trimethylpsoralen plus long wavelength ultraviolet light. When infected cells are exposed to psoralen plus light during peak viral RNA synthesis, formation of virus-specific RNAs is inhibited. Viral RNA species, formed in vivo in the presence of, or treated in vitro with, psoralen plus light, appear to have become degraded when analyzed by sedimentation in sucrose-dimethyl sulfoxide gradients. Treatment with psoralen plus light in vitro results in the loss of infectivity of single-stranded viral RNA.

Coumarins↗