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Biomedical subjects

C T Smith

Publications and source records attributed to C T Smith.

At least 19 recordsLinked to original sources
PubMed1992

Two largest national alliances fine-tune strategies as health care environment changes. Interview by Howard J. Anderson.

The nation's two largest alliances of not-for-profit hospitals and systems are refining their roles for the 1990s. American Health Care Systems (AmHS) and Voluntary Hospitals of America (VHA) are moving away from strategies designed for competition in the marketplace of the 1980s, and toward helping their members change the way they deliver health care in their communities. While AmHS is promoting its health care reform proposal, VHA sees its existing 29 regional organizations of hospitals as a potential infrastructure for the development of community-based, integrated networks of care as envisioned in the AHA's reform plan. Experts add that the alliances clearly have to go beyond group purchasing to serve the changing needs of their members.

Community-Institutional Relations↗
PubMed1992

Hibernation alters the frog's immune system.

The lymphomyeloid organs and blood leukocyte populations of the leopard frog, Rana pipiens, undergo conspicuous changes during hibernation at 4 degrees C. Within the blood, spleen, thymus, jugular bodies, and bone marrow there was a progressive loss of hemopoietic populations resulting in a marked lymphocyte depletion. Termination of the 135-day hibernation period resulted in the restoration of all hemopoietic elements in the blood and lymphomyeloid organs within 30 days. Frogs subjected to experimental hibernation and immunized showed weakened immune responses when brought from the hibernaculum. Plaque-forming cells (PFC) were lower in spleen, jugular bodies, and bone marrow, and serum antibody titers were also lower. Although the kinetics of the primary responses were essentially the same, the secondary responses differed suggesting major rearrangements with respect to the numbers of cells and their function in secreting antibody. The apparent lymphocyte aplasia may contribute to the absence of immunological responsiveness during periods of hibernation.

Animals↗
PubMed1990

Rates of cerebral protein synthesis are linked to slow wave sleep in the rat.

Using L-[1-14C]leucine autoradiography, rates of cerebral and local cerebral protein synthesis were studied during wakefulness, slow wave sleep (SWS) and REM sleep in the rat. In the cerebrum as a whole, the rate at which labelled leucine was incorporated into tissues was positively correlated with the occurrence of slow wave sleep. We failed to observe a significant correlation of protein synthesis rate with either wakefulness or REM sleep. As in the cerebrum as a whole, most discrete brain regions showed moderate positive correlations between the occurrence of SWS and rates of protein synthesis. There were no brain regions in which rates of protein synthesis showed striking correlations with sleep-wake states. Thus, the occurrence of SWS is associated with higher rates of protein synthesis throughout the brain. These data suggest that SWS sleep favors the restoration of cerebral proteins.

Animals↗
PubMed1987

Yeasts in juvenile periodontitis. Preliminary observations by scanning electron microscopy.

Through the use of the electron microscope, yeasts were found invading gingival connective tissue in juvenile periodontitis (JP). Samples (3-mm punch biopsies, including epithelium and underlying connective tissue) were taken apically to periodontal pockets before and after patient treatment with spiramycin. Some samples underwent in vitro treatment with spiramycin. Oval and round yeast cells were found before and after in vivo and after in vitro spiramycin treatment. Larger numbers of yeast cells were seen after spiramycin treatment indicating that their growth might be favored after patient treatment with this antibiotic. This observation has an obvious clinical implication. Budding processes, indicating active yeast multiplication, were observed. Some yeast cells also showed the presence of glycocalyx. Further studies on the role of yeast in the pathogenesis of JP are necessary.

Adolescent↗
PubMed1987

The presence of bacteria in the oral epithelium in periodontal disease. III. Correlation with Langerhans cells.

Langerhans cells (LC) are cell types found in the skin and gingiva. LC have immunological functions as phagocytic cells and as antigen-presenting cells for T and B lymphocytes. Sections from biopsies of the gingiva in cases of periodontal disease were found to have increased numbers of LC. These biopsies also contained intragingival bacteria. Serial sections of frozen specimens of human gingiva were prepared for staining. Hematoxylin and eosin were used for tissue survey, the Gram stain for assessment of bacterial invasion, anti-Leu-6 monoclonal antibody associated with peroxidase technique (PAP) to identify LC, antibacterial sera to Bacteroides gingivalis and Actinobacillus actinomycetemcomitans associated with peroxidase to specifically identify these two common periodontopathogenic bacteria. Additional positive identification of bacteria was performed by preparing the same histological section containing gram-stained particles for scanning electron microscope and transmission electron microscope LC confirmation. The results suggest that the increased number of LC seen in diseased sites of oral epithelium containing intragingival microorganisms may be one of the host immune mechanisms to penetration by bacteria.

Antibodies, Monoclonal↗
PubMed1986

The presence of bacteria in the oral epithelium in periodontal disease. II. Immunohistochemical identification of bacteria.

Serial histological sections of gingiva obtained from each of six advanced adult periodontitis, two localized juvenile periodontitis and two periodontally healthy patients were used for specific identification of bacteria within the oral epithelium and adjacent connective tissue. Healthy gingival biopsies served as controls. Sections from patients and control biopsies were Gram-stained and also screened with antibacterial sera associated with the peroxidase immunocytochemical technique for specific bacterial identification. The "Pop-off" electron microscopic technique was also used to further demonstrate the bacterial nature of peroxidase-stained material. In addition, the possible correlation between bacteria and areas of possible reduced keratinization was investigated. The results showed that sections of orthokeratinized healthy gingiva did not contain bacteria. Gram-stained sections from diseased sites contained large numbers of bacteria in the oral epithelium and adjacent connective tissue. Bacteroides gingivalis and to a lesser extent Capnocytophaga gingivalis were found in periodontitis, and Actinobacillus actinomycetemcomitans was found in juvenile periodontitis when the immunoperoxidase technique was used. The bacterial nature of peroxidase-stained material was confirmed by the "pop-off" technique. In the disease biopsies, bacterial presence was correlated with areas of reduced amounts of keratin suggesting that the oral epithelium may be a portal of entry for bacteria into gingival tissues.

Actinobacillus↗
PubMed1986

Hospital management strategies for fixed-price payment.

The Medicare prospective payment system and pressures from business to change hospital financing demand new management strategies. This article explores specific steps hospital administrators can take to enable their institutions to cope effectively under prospective payment and new market conditions.

Diagnosis-Related Groups↗
PubMed1985

Health care delivery system changes: a special challenge for teaching hospitals.

Changes in the method of financing health care in the United States in order to gain better control over escalating costs are receiving considerable attention. If major changes are made in the system, the nation's teaching hospitals are particularly vulnerable and must be given special consideration. The attributes of teaching hospitals and the special role which they play in the health care delivery system are delineated. Since responsiveness to system changes by teaching hospitals is key to their survival, several short-term and long-term strategies are identified. Teaching hospitals will need to be as innovative in their management and organizational approaches as they are clinically.

Costs and Cost Analysis↗
PubMed1984

A current study of mottled enamel in Texas.

Enamel mottling is strongly associated with the water fluoride level of the community water supply. About 32% of the variation in the mottled enamel scores of subjects aged 7 to 12 was attributable to their community's water fluoride level. Objectionable mottling (moderate mottling) occurred at 2.3 times the currently accepted optimum water fluoride level. Subjects with incomes less than $10,000 have slightly more mottling (mostly moderate mottling) than subjects from higher income families. It should be emphasized that the effect of gender, ethnic group, or family income on enamel mottling is small compared with the effect of water fluoride level. Although many other personal and water supply characteristics were evaluated, virtually none of the remaining variation in mottled enamel scores could be attributed to any of these characteristics.

Adolescent↗
PubMed1983

Effects of limited-target availability on schedule-induced attack.

Pigeons exposed to a 180-sec fixed-time food schedule could attack a rear-projected conspecific target that was available either (a) continuously throughout the interfood interval, (b) randomly during one 30-sec portion of each interfood interval, or (c) during the final 90 sec of each interval. During continuous-target availability, attack was maximal shortly after food ingestion and progressively decreased thereafter. During random-target availability, five of seven pigeons attacked less per target-access period the later that period occurred within the interfood interval, whereas two subjects exhibited relatively high local attack rates even when access periods occurred within the final third of the interval. When the target was available only during the second half of the interfood interval, attack occurred as soon as the target was presented and progressively decreased throughout the remainder of the target-access period. In general, these results show that schedule-induced attack can be increased by limiting the availability of that target and also indicate that such attack can reliably occur at times other than shortly after food delivery.

Aggression↗
PubMed1975

Increases in paradoxical sleep as a result of amygdaloid stimulation.

Holtzman rats were partially and selectively deprived of paradoxical sleep (PS) for a 16 1/2 hr period and allowed to rest for a 7 1/2 hr period each day. Test animals were given mild (60 Hz, 50 muA) unilateral amygdaloid stimulation for one min each day of a 5 day test period. There was a significant increase in PS during the rest periods of test animals on stimulation days when compared to nonstimulated controls. The effect did not last beyond a 5 day period. Only subconvulsive behaviour was observed in two test animals. The similarity to the PS increases in this study to those seen in conventional learning and other stiuations are discussed.

Amygdala↗