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D E Johnson

Publications and source records attributed to D E Johnson.

At least 127 records · Page 7Linked to original sources
PubMed1998

Knowledge management is new competitive edge.

Managing knowledge is emerging as the latest business strategy to get ahead of the competition. In the process of developing knowledge management systems, executives are increasing their awareness and understanding of organizational dynamics, collaboration, corporate learning and knowledge management technology. But Donald E.L. Johnson writes that health care executives must buy into and understand collaboration and corporate learning before they tackle knowledge management.

Economic Competition↗
PubMed1998

Hospitals need to help Medicare HMOs.

Many of the health maintenance organizations that rushed to create Medicare products are bailing out of their Medicare contracts. Donald E.L. Johnson writes that Medicare HMOs face market and government challenges, and hospitals should try to anticipate HMOs' next moves and have responses ready.

Aged↗
PubMed1998

Kleinke's "Bleeding Edge" sees utility role for providers.

Hospitals will evolve into units of health care delivery systems that will eventually resemble utilities, like water and the telephone, according to a new book. Donald E.L. Johnson reviews Bleeding Edge: The Business View of Health Care in the New Century, by J.D. Kleinke, and discusses the strategic implications of Kleinke's predictions.

Cost Allocation↗
PubMed1998

More red ink in 1999; better things to come?

While hospitals, medical group practices and integrated health care delivery systems can expect tight profit margins in 1999, Donald E. L. Johnson writes that both Medicare and private sector payments may stabilize over the next 12 months to bring improved bottom lines.

Advertising↗
PubMed1998

Preoperative versus postoperative chemoradiation for patients with resected pancreatic adenocarcinoma.

Two groups of patients with adenocarcinoma of the pancreas treated with either preoperative chemoradiation (preop CTRT) or postoperative chemoradiation (postop CTRT) were retrospectively analyzed for various treatment-related parameters. Between November 1986 and October 1996, a total of 70 patients with pancreatic adenocarcinoma were enrolled into preop CTRT protocols at our institution. Twenty-five patients with adenocarcinoma of the head of the pancreas underwent pancreaticoduodenectomy with curative intent. After the closure of the preop CTRT protocols, we had the opportunity to perform 23 pancreatic resections without preop CTRT. After surgery, these patients were advised to undergo CTRT. These two groups of patients were therefore selected consecutively, dependent only on the time of referral and no other bias. These two cohorts of patients are compared for various intraoperative parameters, length of hospital stay, pathologic findings, time to recurrence, and survival. Mean age was 65 and 66 years in the preop and postop CTRT groups, respectively. Sex distribution was almost equal. Treatment breaks resulting in greater than 1 week delay in the radiotherapy occurred in 2 (8%) of 25 patients in the preop CTRT group (myelotoxicity in 1 case and biliary sepsis in 1 case), whereas no treatment breaks >1 week occurred in those receiving postop CTRT. Eleven patients in preop CTRT had grade 3 or 4 toxicity, whereas none was noted in those with postop CTRT. There was one postoperative death in the preop CTRT group and none in the postop CTRT group. Mean time to the start of CTRT was 45 days (range, 20-66 days) after pancreaticoduodenectomy. Delay of >60 days to the onset of CTRT occurred in 2 (22%) patients and was attributable to patient delays in time to recover from surgery or patient noncompliance. Furthermore, 5 of 23 patients (22%) in the postop CTRT group did not receive treatment for various reasons. Average estimated operative blood loss was 1933 mL (median 1550) and 1060 mL (median 1000) for preop and postop CTRT groups, respectively. Mean length of operation was 488 minutes (median 480) and 486 minutes (median 480). Median length of postoperative stay was 22 and 20 days (ranges, 9-144 and 10-38). Pathological findings in the resected specimens showed significantly fewer involved nodes in the preop CTRT group (28 vs 87%; P = 0.0006), whereas similar numbers of nodes/patient were counted in each group (14 vs 22, P = 0.11). More negative resection margins were observed in the preop CTRT group (28 vs 56%; P = not significant). A significantly greater amount of fibrosis replacing the tumor was observed in the preop CTRT group (70 vs 40%; P = 0.0001). There were no significant survival differences observed (median 20 months vs 25 months; P = 0.48), in follow-up that ranged from 4 to 76 months (median 44 months for surviving patients) for the preop group and 4 to 40 months (median 16 months for surviving patients) for those with postop CTRT. Local failure either alone or as a component of distant failure occurred in 16 per cent (4 of 25 patients) with preop CTRT and 16.6 per cent (3 of 18) with postop CTRT. Analysis of differences between those treated with preoperative and postoperative CTRT demonstrates similarity in toxicity and effects. However, 22 per cent of patients intended for postoperative therapy did not receive treatment.

Adenocarcinoma↗
PubMed1998

p53 gene therapy in a rat model of hepatocellular carcinoma: intra-arterial delivery of a recombinant adenovirus.

p53 tumor suppressor gene therapy has been proposed for cancers characterized by inactivation of p53 function, and successful therapy will require efficient strategies for gene delivery. To maximize transgene expression in tumors, a clinical strategy has been proposed to treat neoplasms in the liver via hepatic artery administration of a recombinant adenovirus encoding wild-type p53 (rAd-p53). We have developed a syngeneic rat model using a p53mut hepatocellular carcinoma cell line (McA-RH7777) that results in multifocal liver tumor nodules to provide experimental support for this strategy. Treatment of McA-RH7777 cells with rAd-p53 in vitro resulted in efficient transgene expression, growth suppression, and apoptosis. Intrahepatic artery dosing with rAd-p53 or an adenovirus encoding beta-galactosidase (rAd-betagal) increased transgene expression in tumor tissue and decreased systemic exposure when compared with i.v. dosing. Daily hepatic artery dosing of rAd-p53 suppressed tumor growth when compared with untreated rats or animals treated with rAd-betagal. These data demonstrate the potential for arterial gene delivery to tumors using recombinant adenoviruses, and support continued investigation of rAd-p53 gene therapy for liver malignancies.

Adenoviridae↗
PubMed1998

Bcl-2 but not Bax expression is associated with apoptosis in normal and transformed squamous epithelium.

Aberrant regulation of apoptosis may contribute to tumorigenesis. Relative levels of apoptosis regulatory proteins, such as Bcl-2 and Bax as well as interactions of these proteins with other gene products, may contribute to the rate of apoptosis in neoplasia. We examined Bcl-2 expression in 104 squamous cell carcinomas of the head and neck, as well as histologically normal mucosa several centimeters away from the tumor, and in control normal mucosa from patients without cancer. Immunohistochemistry and immunoblotting demonstrated Bcl-2 expression in 30% (31 of 104) of squamous cell carcinoma, with an increase in Bcl-2 protein levels compared with control normal mucosa from noncancer patients. Bcl-2-positive tumors demonstrated a 5-fold decrease in the number of apoptotic cells compared with Bcl-2-negative tumors. Bcl-2 protein expression was associated with poorly differentiated tumor grade but was not correlated with Bax expression or patient survival. These findings demonstrate that Bcl-2 contributes to apoptosis in normal and transformed squamous epithelium.

Adult↗
PubMed1997

Health of children adopted from the former Soviet Union and Eastern Europe. Comparison with preadoptive medical records.

CONTEXT: Children born in the countries of the former Soviet Union and Eastern Europe are now a main source of international adoptions in the United States, but often little information is available about these children prior to adoption. OBJECTIVE: To analyze the preadoptive medical reports of children adopted from Eastern Europe and the former Soviet Union and to compare these reports with their evaluations after arrival in the United States. DESIGN: Case series. SUBJECTS AND SETTING: A total of 56 children adopted from Eastern Europe and the former Soviet Union were evaluated in 2 international adoption clinics. Preadoptive medical records were available for 47 of these children. RESULTS: There were 43 (91%) of 47 medical reports available from the children's birth countries that included multiple unfamiliar neurologic diagnoses. Evaluations in the International Adoption Clinics frequently revealed growth delays (zscore < or = -1 for weight in 44% of children, height in 68%, and head circumference in 43%). Children had 1 month of linear growth lag for every 5 months in an orphanage (r=-0.48, P<.001). Developmental delays were also common (gross motor delays in 70% of children, fine motor in 82%, language in 59%, and social-emotional in 53%). While serious medical problems were found or corroborated in 11 (20%) of the 56 children evaluated in our clinics, neurologic diagnoses cited in preadoptive medical reports were not confirmed. CONCLUSIONS: Preadoptive medical records from these international adoptees included multiple diagnoses suggesting severe neurologic impairment. Although these diagnoses were not confirmed when the children were evaluated in the United States, substantial growth and developmental delays were identified.

Adoption↗
PubMed1997

Fas stimulation induces RB dephosphorylation and proteolysis that is blocked by inhibitors of the ICE protease family.

Fas antigen is a member of the tumor necrosis factor/nerve growth factor receptor family. Stimulation of Fas by Fas ligand or agonistic antibodies results in the activation of interleukin-1 beta converting enzyme-like (ICE-like) proteases, and proteolytic cleavage of poly(ADP-ribose) polymerase (PARP). Ultimately, Fas activation leads to apoptotic cell death. The importance of PARP cleavage to the death process remains unclear. We have hypothesized that the cleavage of other cellular substrates may be important for Fas-mediated apoptosis. Here we show that stimulation of Fas results in significant alterations of retinoblastoma protein (RB). Treatment of Jurkat cells, a human leukemic T cell line, with anti-Fas induces dephosphorylation of RB, followed by proteolytic cleavage. These events precede internucleosomal DNA fragmentation. Dephosphorylation and cleavage of RB are inhibited by a specific tetrapeptide inhibitor of ICE-like proteases or by expression of cowpox virus CrmA protein or the Bcl-2 oncoprotein. Inhibition of these RB changes correlates with inhibition of apoptosis. We propose that cleavage of RB may represent an important step in the pathway of Fas-mediated apoptotic cell death.

Apoptosis↗
PubMed1997

An ultrastructural evaluation of acute 1-nitronaphthalene induced hepatic and pulmonary toxicity in the rat.

1-Nitronaphthalene is a mutagenic particulate of diesel exhaust which causes acute liver and lung toxicity in rodents. The studies presented here describe morphological changes in the lung and liver at several time intervals following a single injection of 1-nitronaphthalene (100 mg/kg, i.p.) in male Sprague-Dawley rats using transmission and scanning electron microscopy. Although both the lungs and liver are injured by 1-nitronaphthalene, the lungs appear to be the primary target organ. Within 4 h of treatment, all 1-nitronaphthalene treated animals exhibited respiratory distress characterized by labored breathing, severe gasping and chromodacryorrhea. The primary ultrastructural alteration were hydropic changes in the non-ciliated bronchiolar (Clara) cells of the distal-most bronchioles of the lung. These were apparent as early as 1 h after 1-nitronaphthalene injection, while adjacent ciliated cells showed no alterations. Over a 24 h period, the bronchioles showed progressive ultrastructural changes leading to necrosis and exfoliation of both ciliated and Clara cells. Interstitial pneumonitis and edema were observed in all animals treated with 1-nitronaphthalene, and was usually associated with bronchioles containing necrotic epithelium. In the liver, ultrastructural changes were observed in the centrilobular hepatocytes at 8 h and consisted of cytomegaly, loss of continuous inner membrane and reduced matrix density of the mitochondria. At 48 h, cellular damage to centrilobular hepatocytes was severe and nearly all mitochondria were damaged. Elevated levels of alanine aminotransferase, aspartate aminotransferase and bilirubin were detected in the serum of animals treated with 1-nitronaphthalene at 8-48 h. In conclusion, 1-nitronaphthalene is a pulmonary toxicant with a unique progression of injury, which primarily damages Clara cells followed by ciliated cells. This disparity is likely due to a difference in the bioactivation of 1-nitronaphthalene. Furthermore, this systemic toxicant also has injurious effects on the centrilobular region of the liver which precedes lung injury.

Animals↗
PubMed1997

Follicle stimulating hormone effects on immature human oocytes: in vitro maturation and hormone production.

PURPOSE: Our purpose was (1) to determine if in vitro maturation of unstimulated oocytes could be improved with the addition of urofollitropin; (2) to evaluate the output of estradiol, testosterone, progesterone, and androstenedione by the cultured oocyte-cumulus complex; and (3) to ascertain if steroid hormone production of the oocyte-cumulus complex correlates with final oocyte maturation stage. METHODS: Fifty-eight immature oocytes were obtained from 11 regularly cycling women undergoing oophorectomy. The oocyte-cumulus complexes were randomly assigned to control medium (Ham's F-10 supplemented with 7.5% fetal bovine serum) or test medium (control medium supplemented with 75 mIU/ml of urofollitropin). RESULTS: (1) The addition of urofollitropin to oocyte culture medium does not significantly increase the ability of the oocyte to achieve the metaphase II stage; (2) the addition of urofollitropin significantly increases the production of progesterone, testosterone, and androstenedione by the oocyte-cumulus complex; and (3) there is no difference in the production of estradiol, progesterone, testosterone, and androstenedione by the oocyte-cumulus complex at the germinal vesicle, metaphase I or metaphase II stage of oocyte maturation. CONCLUSIONS: This information is of importance in the use of oophorectomy specimens for patients who must undergo an oophorectomy but desire to attempt pregnancy using their oocytes, in the use of oophorectomy specimens for donor oocytes, or for patients undergoing in vitro fertilization using immature oocyte collection.

Androstenedione↗
PubMed1997

Relaxation of porcine tracheal smooth muscle by parathyroid hormone-related protein.

Parathyroid hormone-related protein (PTHrp) has been shown to relax uterine and gastrointestinal smooth muscles, but the mechanisms underlying its effects have not been characterized. Furthermore, its effect on pulmonary smooth muscle is unknown. Therefore we designed the present study to determine the PTHrp dose-response; the interaction of PTHrp and PTH; and the role of cyclic nucleotides and potassium channels in the PTHrp response in porcine tracheal smooth muscle (TSM). Our results indicate that, (1-34)PTHrp causes dose-dependent relaxation of TSM; that (1-34)PTHrp and (1-34)PTH demonstrate cross-tachyphylaxis to one another; that phosphodiesterase inhibition augments and phosphodiesterase stimulation attenuates the relaxation response while guanylate cyclase blockade has little effect, and that charybdotoxin and iberiotoxin, inhibitors of large conductance, Ca(2+)-activated, K+ channels, diminish the relaxation response. These findings suggest that (1-34)PTHrp-induced relaxation of TSM is mediated through a common PTHrp/PTH pathway or receptor, stimulation of cAMP and activation of large conductance, Ca(2+)-activated, K+ channels.

1-Methyl-3-isobutylxanthine↗