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Biomedical subjects

A K Miller

Publications and source records attributed to A K Miller.

At least 55 records · Page 3Linked to original sources
PubMed1972

Cephamycins, a new family of beta-lactam antibiotics. IV. In vivo studies.

Cephamycin A was found to be more active in vivo than cephamycin B. In comparison with cephamycin C, cephamycin A was more active against gram-positive organisms but less active against gram-negative organisms. Given subcutaneously, cephamycin C had good in vivo gram-negative activity, comparing favorably with cephalothin and cephaloridine against cephalosporin-susceptible organisms. In general, against the gram-negative organisms, it was more active than cephalothin or cephalosporin C and about as active as cephaloridine. In addition, cephamycin C protected mice against beta-lactamase-producing Proteus cultures, including clinically isolated strains. The compound is remarkably nontoxic. Cephamycin C was detected in the serum and recovered from the urine of treated mice to about the same extent as cephaloridine. Like cephaloridine and cephalosporin C, cephamycin C must be excreted mainly by glomerular filtration, because the use of probenecid did not enhance the therapeutic effectiveness nor concentrations of these agents in the sera of treated mice.

Animals↗
PubMed1971

Antibacterial activity of ronidazole.

Ronidazole, a nitroimidazole that has in vivo antiparasitic and antimycoplasmal activity, also has some in vivo antibacterial activity.

Anti-Bacterial Agents↗
PubMedDate not supplied

Cefoxitin and cephamycins: microbiological studies.

The cephamycins are a family of beta-lactam antibiotics that are produced by actinomycetes and are structurally similar to the cephalosporins. They are characterized by the presence of a 7-alpha-methoxyl group, which confers unusually high resistance to beta-lactamases. Cefoxitin, the first semisynthetic cephamycin, is resistant to almost all beta-lactamases. Cefoxitin retains the 3-carbamoyl group of cephamycin C and thus has excellent metabolic stability. Cefoxitin is bactericidal and almost devoid of any inoculum effect. Active against many cephalothin-resistant gram-negative bacteria, cefoxitin demonstrates a very broad spectrum that includes indole-positive Proteus and many strains of Serratia. In contrast to that of the cephalosporins, cefoxitin's spectrum of activity against anaerobic pathogens includes Bacteroides fragilis. The therapeutic effectiveness of cefoxitin in experimental infections in mice confirms the excellent characteristics of this semisynthetic cephamycin and indicates that it should be a very valuable agent for treatment of bacterial infections.

Animals↗
PubMedDate not supplied

A basic program to correct for split cell error in particles classified by the logarithm of their profile areas.

A program is presented, written in the BASIC computer language, to correct the errors which occur when cell profiles are counted in thin sections of tissue. Given the numbers of profiles in each of M size classes, and the thickness and area of the sections examined, the program calculates the number of cells in each of these classes per mm3 of tissue. The mathematical method is briefly described and it is shown that a useful level of accuracy may be obtained when the correction procedure is used in the study of non-spherical cells.

Cell Count↗
PubMedDate not supplied

Variation with age in the volumes of grey and white matter in the cerebral hemispheres of man: measurements with an image analyser.

The total volumes and relative quantities of grey and white matter have been measured in sixty-five normal male and sixty-five normal female cerebral hemispheres. Fixed hemisphere volume was found to fall linearly at 3.5% per decade for men from 641 ml at the age of 20 to 463 ml at the age of 100. For women the decrease was 1.9% per decade from 531 ml at 20 years to 462 ml at 100 years. After correction for the effects of fixation and for the secular increase in brain size, it was concluded that mean hemisphere volume remained roughly constant between the ages of 20 and 50 years (558 ml for men, 474 ml for women). After the age of 50 the mean volume in both sexes fell at about 2% per decade. The ratio of the volumes of grey to white matter was the same for the two sexes at all ages. Its mean value was 1.3 at the age of 20, falling to 1.1 at the age of 50, then rising steadily to over 1.5 at 100 years. It is impossible in practice to correct these measurements for the effects of fixation or secular change. Fourteen hemispheres from thirteen elderly female dements were also measured. The total volume was 18% lower than for an age-matched group of normals, but the ratio of grey to white matter was identical.

Adult↗
PubMedDate not supplied

Automated differential cell counting on a sector of the normal human hippocampus: the influence of age.

The neurons and the glia of the human hippocampus are notoriously vulnerable in various pathological conditions including those linked to ageing. There may even be differences between the young and the old in the absence of manifest disease. Using an image analyser, systematic measurements of cell numbers in the region of the Sommer (Hl) sector of the human hippocampus have been made on post-mortem tissue from thirty-seven female and forty-nine male subjects aged between 15 and 96 years. In fifteen male and fifteen female subjects both hemispheres were available for analysis so that measurements were made on a total of 116 hemispheres. For each specimen the fresh volume of the hemisphere was measured and corrections subsequently made for changes in size which occurred during fixation, processing, mounting and staining. After all the correction factors had been applied the number of nucleolated neurons was found to fall by about 3.6% per decade (P less than 0.0001). There was no significant age-related change in the number of glia. Marked individual variations were found.

Adolescent↗