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Biomedical subjects

H W Smith

Publications and source records attributed to H W Smith.

At least 91 records · Page 5Linked to original sources
PubMed1978

Primary isolation media for Legionnaires disease bacterium.

Yolk sac suspensions infected with the Legionnaires disease bacterium (LDB) were plated onto 17 different bacteriological agar media. The LDB grew only on Mueller-Hinton agar supplemented with 1% Iso Vitale X and 1% hemoglobin (MH-IH). This medium was subsequently analyzed to determine the components required to support growth of the LDB. L-Cysteine hydrochloride can replace the Iso Vitale X reagent, and soluble ferric pyrophosphate can replace hemoglobin. A new medium, F-G agar, was formulated incorporating these chemicals. Different cultures conditions (oxygen tension, temperature, and pH) were also evaluated. The LDB grew optimally at 35 degrees C under 2.5% CO2 on the F-G agar adjusted to pH 6.9. When infected tissues were inoculated onto both F-G agar and MH-IH, the F-G agar produced colonies of the LDB more rapidly and in greater numbers than did MH-IH.

Bacteria↗
PubMed1977

Double-exposure duplication of preoperative and postoperative 2 X 2 transparencies.

Before and after photographs in plastic surgery are an essential part of the patient's record. They also provide visual data to supplement both primary and continuing education lectures. When successive photographs are used in lectures, a sharp visual memory is required to compare effectively the preoperative and postoperative photograph. The method presented in this article uses a specially constructed frame used as an accessory for one of the common commercial slide copiers. This device makes it possible to copy, duplicate, and frame preoperative and postoperative 2 X 2 transparencies onto a single 2 X 2 transparency without any additional work on the original, such as framing, cutting, and remounting. This technique leaves the original preoperative and postoperative 2 X 2 transparency slides intact for possible use elsewhere in the same lecture or subsequent lectures on the same subject.

Audiovisual Aids↗
PubMed1977

Temperature-sensitive and other mutants of the Essex 70 strain of Newcastle disease virus as vaccines.

The most reliable method of distinguishing strains of low virulence amongst a collection of stock strains of Newcastle disease virus (NDV) was by their failure to produce a good c.p.e. in monolayers of baby hamster kidney cells and of chick embryo cells. This method was of no help in identifying avirulent mutants that emerged in the Essex 70 strain of NDV following ultraviolet light, nitrous acid, hydroxylamine or N-methyl-N'-nitro-N-nitrosoguanidine (NTG) treatment. A marked reduction in the ability to kill developing chick embryos at 41 degrees C was a much more reliable indicator. Several of these temperature-sensitive mutants, most of which had been isolated from NTG-treated virus, were non-lethal for young chicks but they did have a depressive effect on their growth rate. The immunity produced by three of these mutants in chicks free of NDV antibody, but not in chicks possessing appreciable amounts of antibody, was probably even better than that produced by Hitchner B1 strain. All three mutants reverted to virulence during passage in chicks, although in no case were the revertants as virulent as the original Essex 70 strain. The virulent revertants obtained from one of the mutants had lost their temperature-sensitivity and proliferated in large numbers in the tissues of infected chicks. Those obtained from the other two had either not lost, or only partly lost, their temperature-sensitivity; they were found only in low concentrations in the tissues of infected chicks, their concentrations being little different from that found in the tissues of chicks infected with the mutants from which they were derived.

Animals↗
PubMed1977

Treatment of experimental Escherichia coli infection in mice with colicine V.

Concentrated non-toxic preparations of colicine V were obtained by filtering centrifugates of soft-agar cultures of a Col V+ K12 strain of E. coli through Millipore filters in which the colicine V was retained. These preparations, given subcutaneously, favourably influenced the course of disease in mice infected intraperitoneally with a pathogenic strain of E. coli that was very sensitive to colicine V in vitro. A beneficial effect was noted even when treatment was delayed until the mice were visibly ill.

Animals↗
PubMed1977

Palato-pharyngeal cine photography: a technique for developing continuing education films.

A method of Cine photography has been developed to record a variety of plastic and reconstructive surgical procedures in the oral cavity and pharynx. Effective classroom teaching of surgical closure of the cleft palate and the various palatal lengthening procedures including pharyngeal flaps, has been hampered by the lack of quality teaching films demonstrating surgical techniques in color. The small size of the structures involved and the delicate nature of the surgery requires that the surgeon work at close range and directly in front of the mouth. To avoid the shadows cast by the sides of the oral cavity, the surgeon's hands and frequent change of position by the professional photographic team, a head-mounted Cine camera was employed. A "through the surgeon's eye" view for the camera was accomplished by using a parallelogram of beam-splitting mirrors. The resulting photographic film provides the classroom audience with a sense of being in the surgeon's operating position thus having a view superior to that obtained by the surgeon's first assistant. An elaborate system of counter-balancing provides the surgeon with a weightless camera, mirror, and light complex mounted on a football helmet. The football helmet merely served as an interlocking unit enabling the surgeon to compose his own movie while operating.

Audiovisual Aids↗
PubMed1976

Nasopharyngeal pushback in treatment of velopharyngeal insufficiency.

We describe a new technique for extensive retropositioning of the soft palate for the treatment of velopharyngeal insufficiency. This technique is identified as a nasopharyngeal pushback, and has been used repeatedly in conjunction with both a Cronin nasal flap and a superiorly based pharyngeal flap when maximum retropositioning was needed. This procedure has been used for over ten years, each time obtaining an additional pushback distance equal to or greater than the distance achieved by freeling the soft palate from the posterior border of the hard palate.

Cleft Palate↗
PubMed1976

Rhinosporidiosis.

A case of nasal rhinosporidiosis occurred in a 73-year-old man who has lived all his life in the United States. The lesion was treated surgically, and he remains free of disease four years later.

Aged↗
PubMed1976

Neonatal Escherichia coli infections in domestic mammals: transmissibility of pathogenic characteristics.

Apart from the fact that different serotypes are involved, natural and experimental Escherichia coli infection in domestic mammals closely resembles natural E. coli infection in human beings. Some of the important characteristics of E. coli strains that cause disease in domestic mammals are determined by transmissible plasmids. These include enterotoxin, haemolysin and K88 antigen in piglet enteropathogenic strains and enterotoxin and K99 antigen production in calf and lamb enteropathogenic strains; most strains that cause generalized infections in young domestic mammals, i.e. invasive strains, also produce plasmid-determined colicine V. These are all good reasons for employing young domestic mammals as the animal model for studying certain aspects of E. coli infection in human beings. Exploiting the fact that plasmids can be introduced into bacterial cells by conjugation and can be removed from them by "curing", bacterial strains were created that differed from each other, as far as could be determined, only by the presence or absence of one or more of these plasmid-determined properties. These strains, or cell-free preparations of them, were then given by mouth to piglets, calves, lambs and baby rabbits. The results showed that the K88 antigen, probably on account of its adhesive properties, permitted pig enteropathogenic strains of E. coli to proliferate in the small intestine of piglets; the K99 antigen performed a similar function in calf and lamb enteropathogenic strains. The enterotoxin produced by the proliferating organisms was then chiefly responsible for the subsequent movement of fluid from the body into the small intestine and the consequent diarrhoea. Possession of the Col V plasmid contributed significantly to the virulence of invasive strains of E. coli by enabling them to resist more successfully the defence mechanisms of the host.

Animals↗
PubMed1976

Benign periurethral masses in women.

Benign periurethral masses were encountered in 4 women. The masses included 2 vaginal leiomyomas, 1 of which was found simultaneously with a urethral diverticulum, a fibrocystic urethral mass and hyperplastic glandular tissue obstructing the bladder outlet and resembling male prostate. The physical and endoscopic features were helpful in establishing the benign nature and extent of the lesions. Although the bladder base was deformed on an excretory urographic cystogram in each case the radiographic features were non-specific except as they applied to a urethral diverticulum. Transvaginal needle biopsy is recommended in contemplation of open surgical excision. Leiomyomas are best approached transvaginally and anterior urethral masses can be reached suprapubically.

Adult↗