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Biomedical subjects

H A Baker

Publications and source records attributed to H A Baker.

7 recordsLinked to original sources
PubMed1992

Effectiveness of decremental diameter balloon catheters (tapered balloon).

Natural tapering of coronary arteries from larger proximal to smaller distal diameters often creates a dilemma for optimal balloon sizing during percutaneous transluminal coronary angioplasty (PTCA). To demonstrate the need for new dilating catheters suitable for tapered coronary anatomy, 100 consecutive coronary arteries were measured by videodensitometry, 1 cm proximal and distal to the stenosis. In 23 arteries there was a 1 mm or greater taper and 19 arteries showed a 0.5 to 0.99 mm taper. Only 50 arteries showed a nearly uniform diameter at the site of the stenosis, and 8 arteries demonstrated reverse taper, i.e., distal was greater than proximal diameter. To avoid balloon size mismatch with significant tapering, decremental diameter balloon catheters were developed. Series I tapers from 3.5 to 3.0 mm and series II from 3.0 to 2.5 mm over a balloon length of 25 mm. Tapered balloons were used in 80 patients with 94 tapered coronary arteries. Before PTCA, proximal, stenotic and distal mean diameters measured 3.6, 1.1 and 2.6 mm, respectively; after PTCA, proximal, stenotic and distal diameters measured 3.6, 2.8 and 2.5 mm, respectively, thus maintaining the natural tapering after effective dilatation. Only 2 arteries (2.1%) showed significant dissection, with no abrupt occlusions, and none requiring bypass surgery. In summary, decremental diameter balloon catheters provide optimal dilation in tapered arterial segments with few complications and offer a new approach to balloon sizing.

Angioplasty, Balloon, Coronary↗
PubMed1977

Histochemical and biochemical characterization of the rat paracervical ganglion.

The nature and identity of the catecholamines in the paracervical ganglion and superior cervical ganglion small, intensely fluorescent (SIF) cells were investigated using fluorescence histochemical and immunohistochemical techniques. The paracervical ganglion SIF cells were found to contain norepinephrine and the superior cervical ganglion SIF cells, dopamine. The norepinephrine content of the paracervical ganglion SIF cells averaged about 72 ng/ganglion and did not change during the rat estrus cycle. The activity of the enzyme tyrosine hydroxylase in the PCG was very low (about 0.48 nmoles DOPA formed/h/mg protein) and was about 1/50th of the activity of the enzyme in the SCG, where it averaged about 23.90 nmoles DOPA formed/h/mg protein. These experiments suggested that the paracervical ganglion has large numbers of norepinephrine containing SIF cells with a relatively slow turnover of their catecholamine content.

Adrenal Medulla↗
PubMed1976

Comparison of antimicrobial activity of nuclear-substituted aromatic esters of 5-dimethylamino-1-phenyl-3-pentanol and 3-dimethylamino-1-phenyl-1-propanol with related cyclic analogs.

A series of six aromatic esters of both 5-dimethyl-amino-1-phenyl-3-pentanol and 3-dimethylamino-1-(2-phenylcyclohexyl)-1-propanol was prepared. Antimicrobial evaluation showed that the cyclic analogs had approximately twice the activity of the open chain series; in particular, the o-chlorophenyl ester showed pronounced activity against three pathogenic fungi at approximately 10 ppm. Aromatic esters of 3-dimethylamino-1-phenyl-1-propanol were prepared and demonstrated lower activity than two esters of 2-dimethylamino-1-phenylcyclohexanol. The screening results showed that the best activity was found when a dimethylene chain was present between the phenyl ring and the carbon atom bearing the acyloxy function and that the cyclic derivatives were more active than their more flexible counterparts.

Amino Alcohols↗
PubMed1975

Antimicrobial evaluation of diastereoisomeric 2-dimethylaminomethyl-6-phenylcyclohexanols and related esters.

2-Dimethylaminomethyl-6-phenylcyclohexanone was reduced to give the isomeric 2-dimethylaminomethyl-6-phenylcyclohexanols, which were then converted to a number of novel esters. These derivatives were screened against a wide range of microorganisms. The alcohol possessing an axial hydroxy group had high activity against Candida albicans, in contradistinction to the isomer having an equatorial hydroxy function, which was approximately 30 times less active. The esters from the isomeric alcohols demonstrated a low level of antimicrobial activity with the exception of the 10-undecenoyl ester of 2-dimethylaminomethyl-6-phenylcyclohexanol (possessing the equatorial hydroxy group), which showed significant activity against three pathogenic fungi.

Animals↗
PubMed1975

Naphthyridinomycin, a new broad-spectrum antibiotic.

A new antibiotic, naphthyridinomycin, was isolated in crystalline form from the culture filtrate of Streptomyces lusitanus AY B-1026. The antibiotic is active against a large number of both gram-positive and gram-negative bacteria, and inactive against Candida albicans, Trichophyton granulosum and Microsporum gypseum. The antibiotic is toxic in mice.

Animals↗