Biomedical subjects
K Smith
Publications and source records attributed to K Smith.
Exposure of bovine cornea to different strains of Moraxella bovis and to other bacterial species in vitro.
A collection of strains of Moraxella bovis, some pathogenic and some non-pathogenic in cattle, together with other M. bovis preparations, Neisseria ovis, Staphylococcus aureus and Moraxella non-liquefaciens were studied by scanning electron microscopy for their affinity to bovine corneal preparations in vitro. The in vitro procedure provides a convenient method for studies on host-pathogen interactions at the early stage of pathogenesis. The results corresponded well with the pathogenicity of the respective strains and species in cattle. It is considered that the pathogenicity of M. bovis is associated with at least two factors, piliation and the ability to produce pit-like depressions in corneal epithelial cells. The other bacterial species, which are not thought to play an important role in infectious bovine keratoconjunctivitis, had the ability to adhere to the bovine cornea but did not produce pits. The pitting factor of M. bovis is of interest in relation to studies on vaccination against infectious bovine keratoconjunctivitis.
A study of calcergy in the rat induced by the implantation of polyurethane sponges soaked in lead acetate.
Polyurethane sponges were soaked in a 5 mg/ml solution of lead acetate, dried, and implanted subcutaneously in rats. Sponges soaked in distilled water were implanted as controls. The reaction to the sponges was studied from 5 h to 140 days after implantation, utilising sponge dry weight gain, rate of ingrowth of granulation tissue, histology and electron microscopy. Five hours after implantation, test sponges showed lead phosphate deposits in the central sponge zone and by one day the deposits stained positively for calcium. Transmission electron microscopy (TEM) showed needle-shaped crystals of hydroxyapatite. Ingrowth of granulation tissue into test sponges was delayed. Breakdown of the sponge matrix was observed in control sponges after 140 days. This model highlighted the physicochemical nature of the calcergic reaction, implicating fluid transudates/exudates in the initial stages.
Personal and interpersonal characteristics associated with childhood obesity.
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Family influences on hopelessness among children early in the cancer experience.
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A morphological study of macrophage and synovial cell interactions with hydroxyapatite crystals.
Hydroxyapatite crystals have been found in synovial fluids and periarticular spaces in association with osteoarthritis. This study examined the morphology of the interaction of macrophages and synovial cells with hydroxyapatite in order to determine the fate of hydroxyapatite over an extended culture period. Mouse peritoneal macrophages and bovine synovial cells were grown as monolayers. The morphology of the interaction between hydroxyapatite crystals (HAC) and these cells was studied by light microscopy, transmission and scanning electron microscopy for up to 14 days. Phagocytosis of HAC, phagosome formation, and concentration of crystal aggregates around the cells began within four minutes of their addition to the cultures. Phagocytosis and cellular aggregation continued after this time. HAC caused minimal cellular disruption despite the uptake of large amounts of crystalline material and significant cellular enlargement. HAC remained within cells for the duration of the study without any apparent dissolution by the cells. Whether macrophages are stimulated to produce interleukin I as a result of HAC uptake is currently under investigation.
Hearing disorder and cognitive function of individuals with Down syndrome.
The relationship between hearing disorder and performance on intelligence tests among 28 children and young adults with Down syndrome was investigated. Intellectual and audiological assessments were obtained and evaluated in a multiple regression analysis. Performance on intelligence tests by individuals with abnormal tympanograms was inferior to that of individuals with normal tympanograms. Hearing sensitivity measures were uncorrelated. Findings suggest the need for an awareness of the potential impact of middle ear disorder when assessing intellectual functioning and the importance of otological care for infants and young children with Down syndrome.
Suicide assessment. An ego vulnerabilities approach.
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Low-dose chloramphenicol stimulates granulocyte/monocyte colony-forming units.
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The effects of pregnancy on patients with hyperprolactinemia.
Seventy women with amenorrhea with or without galactorrhea associated with high serum prolactin levels and radiologic evidence of pituitary tumors were treated with transsphenoidal tumor resection. The prolactin level was measured in 29 patients before pregnancy, at 3 months post partum or cessation of lactation, and at 6-month intervals thereafter. The results were compared to those of 18 patients who had hyperprolactinemia but no demonstrable radiologic evidence of a pituitary tumor and who responded to bromocriptine and conceived. Our investigations showed that operation resulted in normalization of serum prolactin levels in 74% of patients. Forty of the 49 patients less than 36 years old conceived (80%). Five of 29 patients who were studied before and after operation as well as after delivery showed an increase in serum prolactin levels post partum and persistent amenorrhea suggesting recurrence. Six of the 18 patients who became pregnant after bromocriptine also showed a significant rise in serum prolactin levels above the treatment level. None of the patients in the two groups developed visual changes or symptoms or radiologic changes during pregnancy. These results showed that transsphenoidal operation has a high incidence of success, but some patients may show a rise of serum prolactin levels and persistent amenorrhea after pregnancy or passage of time, suggesting recurrence. Some patients who become pregnant after bromocriptine therapy may have further rises in prolactin greater than pretreatment levels. Follow-up of these patients is indicated.
Activity attendance, hospital expectations, and suicide.
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Effect of various vitamin D analogs on plasma calcium and phosphorus and intestinal calcium absorption in fed and unfed American eels, Anguilla rostrata.
Injection of about 1 ng/g body wt per day of either vitamin D3 or 1,25-(OH)2-vitamin D3 for 7 days induces hypercalcemia and hyperphosphatemia in fed American eels, Anguilla rostrata, but only hyperphosphatemia in unfed eels. These same analogs also stimulated the uptake of 45Ca from intestinal sacs in situ. The vitamin D3 appeared to be relatively more effective than the 1,25-(OH)2D3 metabolite and chlorpromazine inhibited the effect of vitamin D3 on intestinal calcium uptake. 7-Dehydrocholesterol, vitamin D2, and 24,25-(OH)2D3 did not stimulate hypercalcemia, hyperphosphatemia, or intestinal calcium uptake.
Characterization and quantification of epidermal and dermal glucocorticoid receptors in the rat.
The interaction between [3H]triamcinolone acetonide and cytosol proteins was studied in separated epidermis and dermis of neonatal rats. Both tissues possessed a binding site with a high affinity (dissociation constant = 0.2 nM) and a low capacity (150-220 fmol/mg protein) for triamcinolone acetonide. The binding site in each tissue cytosol was inactivated by heating at 37 degrees C or by incubating with either trypsin, Triton X-100 or NaCl. The second-order rate constant of association was 1.99 X 10(6)M-1min-1 for the epidermal, and 1.65 X 10(6)M-1min-1 for the dermal receptor binding site. Quantitatively there was a difference between the two tissues with 82% of the receptor being found in the dermis and 18% in the epidermis.
Lethality of suicide attempt rating scale.
An 11-point (0-10) scale for measuring the degree of lethality of suicide attempts is presented. The scale has nine example "anchors" and uses the relative lethality of an extensive table of drugs. The psychometric studies show the scale to be of at least equal-interval, possibly even ratio measurement level. The equal-interval quality allows suicidal behaviors to be specified in numeric relationship to each other relieving us of the burden of using unquantified labels such as "mild," "moderate," and "serious." Having a standardized, commonly used reference scale should greatly facilitate our research and clinical efforts to communicate our findings. The scale can be used reliably by nonmedical personnel with no prior training.
Malate dehydrogenases from actinomycetes: structural comparison of Thermoactinomyces enzyme with other actinomycete and Bacillus enzymes.
Malate dehydrogenases from bacteria belonging to the genus Thermoactinomyces are tetrameric, like those from Bacillus spp., and exhibit a high degree of structural homology to Bacillus malate dehydrogenase as judged by immunological cross-reactivity. Malate dehydrogenases from other actinomycetes are dimers and do not cross-react with antibodies to Bacillus malate dehydrogenase.
Fibre glass induced synovitis.
Chronic synovitis developed in the dorsal extensor sheath of the hand of a 25-year-old manufacturer of fibre glass reinforced boats and surfboards . Particles found in synovial fluid aspirates were similar in morphology and elemental content to unused fibre glass and particles found in dust from the workshop floor. It was concluded that hard disc grinding required during manufacture resulted in percutaneous implantation of small glass particles, leading to chronic synovitis and effusion.
Results of testing fifteen glycol ethers in a short-term in vivo reproductive toxicity assay.
Fifteen glycol ethers were investigated for their potential to cause adverse reproductive toxic effects using an in vivo mouse screening bioassay. Pregnant mice were orally dosed once per day on days 7 through 14 of gestation at concentrations causing 0 to 41% maternal mortality. Reproductive endpoints included pup survival in utero (percent of live litters/pregnant survivors), pup perinatal and postnatal survival (number of live pups per litter, number of dead pups per litter, and pup survival to 2.5 days of age), and pup body weight statistics (weight at birth and weight at 2.5 days of age). The study was conducted in two phases: a dose range-finding phase using nonpregnant female mice, and a definitive reproductive phase using time-mated mice. The range-finding phase sought to identify, for each chemical, the maternal LD10 as the target dose. However, based upon reproductive phase results, such an exact dose was impractical to achieve. Thus, a range from the LD5 to the LD20 was considered a sufficient challenge dose that would not affect results due to high mortality, i.e., greater than the LD20. Glycol ethers were assigned to groups having different priorities for further testing based upon whether a sufficient challenge dose was administered and the degree of effects recorded for each chemical.(ABSTRACT TRUNCATED AT 250 WORDS)