Biomedical subjects
Publications and source records attributed to M K Chen.
Two health status indices applicable to individuals and groups are presented for research and health programme evaluation purposes. Both indices are functions of distances from cultural or group norms of the healthy state on a number of physiological dimensions that are theoretically or empirically related to health. Ways of deriving group norms are briefly discussed.
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PURPOSE: Deep neck infections may be lethal if life-threatening complications occur, especially in immunocompromised hosts such as diabetic patients. This study was undertaken to better define the clinical features and prognosis of deep neck infections in the diabetic patients with special emphasis on the use of empirical antibiotics and the role and timing of surgical management. PATIENTS AND METHODS: A retrospective analysis of 105 consecutive patients treated at a single institution during a 9-year period was conducted. Of these, 30 patients also presented with diabetes mellitus. RESULTS: Compared with the nondiabetic patients, the unique features of deep neck infections in diabetic patients were as follows: (1) older age, (2) tendency of unclear infection source, (3) tendency to involve multiple spaces, (4) required more aggressive surgical intervention, (5) prolonged hospitalization, and (6) higher complication rate. The differences were statistically significant (P< .05). There were no significant differences in the complete blood count/ differential count positive findings and fever between the 2 groups (P> .05). Bacterial cultures showed that Klebsilla pneumoniae was the most common causative pathogen in diabetic patients. CONCLUSIONS: In deep neck infection patients with diabetes mellitus, the clinical course is more severe and there is a poorer prognosis. Thus, in treating them, we should keep close observation, appropriately control the diabetes, detect the life-threatening complications early, perform aggressive surgical treatment if fluctuation or complication occurs, and take into account the preponderance of K pneumoniae when administering the empirical antibiotics.
An in vitro bioartificial skin construct (BSC) model was studied to see how inflammatory infiltration affects apoptosis in skin that has been thermally injured. The BSC was used as a target organ. Control BSCs without leukocytes (CON) were burned (BCON) by scalding with phosphate-buffered saline heated to 70 degrees C for 6 seconds, and they were then cooled with room temperature phosphate-buffered saline for 15 seconds. Human alloimmunocytes were added to CON to create rejection cultures (REJ) and to BCON to create burned rejection cultures (BREJ). Slides were stained with hematoxylin and eosin and anti-Lewis antibody. In situ labeling of apoptosis was measured by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). Those sections that were immunostained for Lewis Y were analyzed for intensity stain index (ISI = [sigma P0 x I0]/ total tissue area in pixels). TUNEL was quantified with the following equation: no. of total apoptotic cells / total tissue area. Necrosis and blister formation in the epidermal layer were evident in BCON and BREJ. Pyknosis and nuclear fragmentation-indicators of apoptosis-were also present. Phagocytosis of keratinocytes by leukocytes was seen in REJ and BREJ. Immunostaining showed greater expression of Lewis Y antigen, as determined by ISI, in REJ as opposed to CON (58.2+/-2.3 vs. 36.4+/-2.3, respectively, P<.001), but no significant difference was found between BCON and BREJ (55.0+/-5.7 vs. 60.5+/-3.4, respectively) and REJ and BREJ (58.3+/-2.3 vs. 60.5+/-3.4, respectively). TUNEL staining indicated the presence of apoptosis as follows: REJ versus CON (0.0015+/-0.0002 vs. 0.0003+/-0.0001, respectively, P<.001); BREJ versus BCON (0.0031+/-0.0006 vs. 0.0018+/-0.0004, respectively, P<.05); REJ versus BREJ (0.0015+/-0.0002 vs. 0.0031+/-0.0006, respectively, P = .007). The presence of leukocytes and thermal injury induces apoptosis in BSC. The combination of these two variables results in increased apoptosis as determined by TUNEL. These findings suggest that a common pathway for skin injury may include inappropriate regulation of apoptosis exacerbated by a mechanism that includes inflammatory cellular infiltration.
The gut plays a key role in interorgan glutamine metabolism in normal and catabolic states. During critical illness, the gut responds to prevailing metabolic pressures that may result in a temporary "reset" in interorgan glutamine flow. As the body recovers from the disease process, the alterations in gut glutamine metabolism revert to normal, which helps restore glutamine homeostasis. Overwhelming stresses, such as severe systemic infection, may lead to permanent organ dysfunction and further adaptive changes in glutamine metabolism.
In critically ill surgical patients, nutritional therapy is an important component of overall care. As our knowledge increases, "tailor-made" diets designed to meet specific nutritional requirements in specific patients may play an important role. Although the data reviewed here suggest that glutamine-supplemented diets may have a significant impact in some clinical settings, it should be emphasized that additional carefully designed studies are necessary before the use of glutamine-enriched nutrition in critically ill patients should be advocated. It is clear, however, that the concept that the intestine is an organ of inactivity during critical illness merits reconsideration.
Fast-growing tumors are major glutamine consumers and may alter host glutamine metabolism to benefit the tumor. Previous studies from our laboratory have demonstrated that the liver switches from an organ of glutamine balance to one of glutamine release with progressive malignant growth. However, the regulation of this change is unclear. This study examined tumor modulation of hepatic glutamine metabolism by determining the activities of glutaminase, the principle enzyme of glutamine degradation, and glutamine synthetase, the principal enzyme of glutamine synthesis. Hepatic glutamine content was also determined. Rats with a fast-growing subcutaneous fibrosarcoma (TBR) and pair-fed controls were studied at 2 and 3 weeks after tumor or sham implantation, when the tumors comprised approximately 5% and 20% of total body weight. Arterial glutamine fell with progressive tumor growth (608 +/- 26 mumol/L in controls vs 494 +/- 15 in TBR, p less than 0.005) and was not attributable to a diminished food intake. Hepatic glutamine content was increased 45% (p less than 0.01) in tumor rats at 2 weeks due in part to a 35% fall in liver glutaminase activity. At 3 weeks, glutamine synthetase activity increased by 43% (0.58 +/- 0.07 mumol/mg of protein/hr in controls vs 0.83 +/- 0.04 in TBR, p less than 0.01) whereas glutaminase remained depressed (2.68 +/- 0.12 mumol/mg of protein/hr in controls vs 2.22 +/- 0.15 in TBR, p less than 0.05) and glutamine content fell compared to 2 week tumor-bearing rats, consistent with accelerated hepatic glutamine release. Tumors may alter liver glutamine metabolism by modulating hepatic enzyme activity in order to provide circulating glutamine for the growing malignancy.
Analyzing data from some 8,000 adults in the United States reveals that adult diabetes is highly associated with age but not with sex. Older adults are more likely to have diabetes than younger adults. For younger adults diabetes is associated with body mass and blood pressure but not with physical activity level. Those who are above the median in body mass or who are hypertensive have higher risks of being afflicted with diabetes than those who are below the median in body mass or who are normotensive. For older adults diabetes is not associated with blood pressure but is highly associated with physical activity level and a measure of body mass based on maximum reported weight. Those who are lighter or who are physically active are much less likely to be diabetic than those who are heavier or who are physically inactive. We further found that for these adults the association between physical activity level and diabetes is independent of body mass. The epidemiological evidence strongly supports the conventional wisdom of dealing with diabetes by reducing body weight, lowering blood pressure, and particularly for older adults, engaging in some kind of regular physical activity.
A population health status index designated as the gross national health product (GNHP) is proposed as a general measure of the health of nations or population groups. The GNHP integrates mortality and disability data into a single number in units of disability-free life years lived per 100,000 population. It is based primarily on mortality ratios and life expectancies of component age groups of the population, modified by their respective disability experiences. A computational example with data currently available on U.S. geographic regions from publications of the National Center for Health Statistics shows that the GNHP was highest in the West, indicating the highest number of disability-free years lived. Because of simplicity in its computation and interpretation, the GNHP can be used by health systems agencies (HSAs) in monitoring their performance or in conducting comparative studies.
A new quantitative index is proposed to measure the degree to which the health care needs of a population are met. It is based on the health goals model of Lester Breslow and A. R. Somers, who listed the kinds and frequencies of health services appropriate for each of 10 developmental and maturational stages of life. The population is further divided into the sick and well segments of each of the 10 groups; the sick need treatment and the well and asymptomatic need preventive care. The index is the geometric mean of the proportions of the people in the stages whose utilization experiences conform to the services and goals appropriate for their respective group. The counting system requires the minimum information as to whether the person has received the necessary treatment for his condition if he is sick or made the requisite number of professional visits for preventive care if he is well. The index is best considered a heuristic tool for understanding a complex problem.