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Biomedical subjects

J A Gilbert

Publications and source records attributed to J A Gilbert.

At least 37 records · Page 2Linked to original sources
PubMed1998

Disease management hits home.

Patients suffering from chronic illnesses, such as diabetes, asthma, congestive heart failure and cancer, are beginning to find significant value in technologies designed to help them take care of themselves at home. And providers and payers are finding that new home care information technologies are helping to curb costs.

Chronic Disease↗
PubMed1998

Physician data entry: providing options is essential.

Getting doctors to enter data into computer-based patient records systems is a challenge. Many physicians are resisting using any of the available options, choosing instead to stick with dictating their notes for later transcription. To build support among physicians for electronic records, many health care organizations are placing a premium on identifying the easiest and most efficient data entry methods.

Attitude of Health Personnel↗
PubMed1998

Sending out an SOS: the role of help desks.

Help desks are a relatively new phenomenon among health care organizations. Just a few years ago, centralized technical support for computer users was viewed as an expensive and unnecessary luxury. But with the onslaught of larger and more complex organizations, including integrated delivery systems, the need for structured technical support has grown.

Computer User Training↗
PubMed1998

Beyond billboards: building interactive Web sites.

More organizations are developing interactive Web sites that go beyond simple billboard-like advertising. These hospitals, integrated delivery systems, physician group practices and managed care organizations are finding that interactive Web sites are helping them improve service for a modest cost.

Community Participation↗
PubMed1997

Evaluation of the frictional properties of an elastomer with enhanced lipid-adsorbing ability.

Wear particle production in load-bearing orthopaedic implants is one of the major factors currently limiting the service life of the implant. Most of the research carried out to date in attempting to solve this problem has used the approach of finding more wear-resistant biocompatible material pairs. In contrast, other researchers have attempted to reduce wear by encouraging elastohydrodynamic film formation through the use of elastomeric bearing surfaces. Unfortunately, these elastomeric bearing surfaces have poor tribological properties when a fluid film is not present. Boundary lubrication of an elastomeric orthopaedic bearing may alleviate some of these difficulties. The purpose of this research was to fabricate and characterize an elastomeric material that had a surface capable of specifically adsorbing a naturally occurring boundary lubricant. Dipalmitoyl phosphatidylcholine (DPPC) has been previously shown to be able to act as a boundary lubricant at stresses that occur in human load-bearing joints such as the hip and knee; therefore, DPPC was chosen for use in this study. It was expected that in an aqueous liposome suspension the static coefficient of friction microseconds of such a material would be lower, and increase less quickly over time, than a similar material without an ability to adsorb specifically DPPC when articulated against a polished chrome steel ball bearing. The lipid-adsorbing elastomer did not possess the desired tribological properties. This result was attributed to the polymer adsorbing the DPPC in the liposome phase and not in the bilayer phase, and interaction among the polymeric surface, DPPC and water. This approach to lubricating orthopaedic bearings was shown to have some merit, but a great deal of work needs to be done before such an approach can be used on a clinically available material.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1997

Alveolar bone loss one year following ovariectomy in sheep.

There is little information concerning the incidence of alveolar bone loss in estrogen-deficient women. Ovariectomized sheep are valid models for study of the effects of estrogen deficiency on bone metabolism. The objective of this study was to compare alveolar bone loss in control (C) and ovariectomized sheep (OVX) at 3 and 12 months following surgery. OVX animals had decreased serum levels of 17-beta-estradiol and increased serum levels of osteocalcin, IL-6, and urinary levels of deoxypyridinoline which, taken together, suggest development of osteoporosis. The mean probing depths and percentage of sites with pocket depths 4 to 6 mm and > 6 mm were significantly greater in OVX than C at each time period and in OVX were significantly greater at 12 months that at 3 months. Gingival tissue interleukin-6 (IL-6) levels (but not the number of IL-6(+) cells) were elevated adjacent to deep periodontal pockets; however, there was no significant elevation of levels of the proinflammatory cytokines IL-1 beta and IL-8 within gingiva. Taken together, the data suggest a systemic contribution for progression of periodontal disease associated with estrogen deficiency. This may involve upregulation of systemic IL-6 synthesis and transfer to gingiva in serum, resulting in enhanced IL-6 accumulation within the gingival tissues or reduced bone density allowing for a greater amount of alveolar bone loss.

Alveolar Bone Loss↗
PubMed1996

Fecal marker variability in colorectal cancer: calprotectin versus hemoglobin.

BACKGROUND: Blood products like hemoglobin are problematic as markers for colorectal neoplasia because bleeding is intermittent. Levels of calprotectin, a leukocyte-derived protein, are increased in stools from colorectal cancer patients. However, this blood constituent may gain luminal access via interstitial leukocyte migration, which could be a less variable mechanism of entry than bleeding. METHODS: To correlate the levels of and to compare the variability of fecal calprotectin and hemoglobin, quantitative assays were performed independently on multiple serially collected stools from 14 patients with colorectal cancer. Marker level association was estimated with Pearson's correlation coefficient, and variation estimated with an analysis of variance model. RESULTS: Fecal calprotectin and hemoglobin levels were discordant in 55 (50%) of 110 matched aliquots, and marker levels failed to correlate. The estimated between-subject correlation was -0.10 (95% CI, -0.60 to 0.46), and mean within-subject correlation -0.27 (95% CI, -0.73 to 0.34). The between-stool coefficient of variation was less for calprotectin (22%) than for hemoglobin (80%). CONCLUSIONS: In patients with colorectal cancer, the mechanism of luminal calprotectin entry appears to be both different from and less erratic than bleeding.

Aged↗
PubMed1995

Elevated aromatic-L-amino acid decarboxylase in human carcinoid tumors.

The carcinoid neoplasm is marked by excessive serotonin, synthesized by the conversion of tryptophan (Trp) to 5-hydroxytryptophan by tryptophan hydroxylase (TPH) (EC 1.14.16.4) and decarboxylation of 5-hydroxytryptophan by aromatic-L-amino acid decarboxylase (AAAD) (EC 4.1.1.28). Because almost no biochemical data were available on human carcinoid TPH and AAAD, we have characterized these enzymes as a preliminary step to developing mechanism-based agents selective against carcinoid tumors. TPH was detected in all fourteen carcinoids analyzed [Km = 185 +/- 17 microM (mean +/- SEM); Vmax = 2.4 +/- 1.2 nmol/hr/mg protein]. AAAD was detected in thirteen tumors (Km = 45 +/- 6.7 microM; Vmax = 11 +/- 2.0 nmol/min/mg protein). In a subset of hepatic metastatic tumors obtained with adjacent normal liver, the Km and Vmax of TPH (N = 6) and the Km of AAAD (N = 7) were comparable in both tissues. However, the Vmax of carcinoid AAAD was 50-fold higher (P < 0.002) than that in normal liver (13 +/- 3.1 vs 0.26 +/- 0.04 nmol/min/mg protein). Western immunoblot analysis indicated that AAAD polypeptide content of carcinoid tumor was > 20-fold higher than in adjacent normal liver. These results suggest that AAAD might be an appropriate target for enzyme-activated cytotoxic agents for carcinoid tumors.

Animals↗
PubMed1995

Spontaneous bacterial peritonitis: an update.

OBJECTIVE: To describe spontaneous bacterial peritonitis (SBP) in the context of currently accepted criteria for diagnosis, treatment, and prevention. DESIGN: A review of SBP and its associated etiopathogenic factors is presented. MATERIAL AND METHODS: Numerous studies on mechanisms of disease, diagnosis, treatment, and prevention are discussed. Diagnostic and therapeutic algorithms are presented. RESULTS: Peritonitis in patients with ascites in the absence of secondary causes, such as peforation of a viscus, occurs primarily in patients with end-stage liver disease. Enteric organisms, mainly gram-negative bacilli, probably translocate to regional lymph nodes to produce bacteremia and seeding of ascitic fluid. Signs and symptoms of peritonitis are usually subtle. The ascitic fluid polymorphonuclear leukocyte count is the best determinant for early diagnosis and treatment of SBP. Third-generation cephalosporins such as cefotaxime are considered the drugs of choice for treatment, whereas quinolones such as norfloxacin are used to decrease recurrence. CONCLUSION: Despite increased awareness, early diagnosis, and prompt and effective antimicrobial therapy, SBP recurs frequently and is associated with a high mortality rate. Patients with SBP should be assessed for candidacy for liver transplantation.

Bacterial Infections↗
PubMed1994

Strain profiles for circular cell culture plates containing flexible surfaces employed to mechanically deform cells in vitro.

Cells in the body are constantly subjected to cyclic mechanical deformation involving tension, compression, or shear strain or all three. A mechanical loading system which deforms cultured cells in vitro was analyzed in order to quantify the deformation or strain to which the cells are subjected. The dynamic system utilizes vacuum pressure to deform a circular silicone rubber substrate on which cells are cultured. These thick circular growth surfaces or plates are formed in the bottoms of the wells of 6-well culture plates. An axisymmetric model was formulated and analyzed using rectangular hyperelastic elements in a finite element analysis (FEA) software package. The thick circular plate has some disadvantages such as difficulty in observing cells and a nonhomogeneous strain profile which is maximum at the periphery and minimal at the center. A thinner circular surface (a thin plate) was also investigated in order to provide a more homogeneous strain profile. The radial strain on the thick circular plate, as determined by FEA, was nonlinear with a peak strain value of 0.30 (vacuum pressure of 22 kPa) about three-quarters of the distance from the center to the edge. In contrast, the radial strain of the thin circular plate was moderately constant across the surface. The circumferential strain for both of these models was less than the radial strain except for the center where they are equal. Avian tendon cells were cultured on the surface of a thick plate and exposed to cyclic strains for 24 h at a rate of 0.17 Hz and observed for cellular alignment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗