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Biomedical subjects

L Rosenberg

Publications and source records attributed to L Rosenberg.

At least 37 records · Page 2Linked to original sources
PubMed2001

Ratios of charged antiparticles-to-particles near mid-rapidity in Au + Au collisions at sqrt[s(NN)]=130 GeV.

We have measured the ratios of antiparticles to particles for charged pions, kaons, and protons near mid-rapidity in central Au+Au collisions at sqrt[s(NN)] = 130 GeV. We observe / = 1.00+/-0.01(stat)+/-0.02(syst), / = 0.91+/-0.07(stat)+/-0.06(syst), and / = 0.60+/-0.04(stat)+/-0.06(syst). The / and / ratios give a consistent estimate of the baryo-chemical potential mu(B) of 45 MeV, a factor of 5-6 smaller than in central Pb+Pb collisions at sqrt[s(NN)] = 17.2 GeV.

Journal Article↗
PubMed2001

Low-dose oral contraceptive use and the risk of myocardial infarction.

BACKGROUND: Studies of oral contraceptives (OCs) containing 50 microg or more of estrogen suggest an increased risk of myocardial infarction (MI) among current users, particularly if they smoke heavily. OBJECTIVE: To assess whether use of the newer lower-dose OCs increases the risk of MI. METHODS: A case-control study was conducted from January 1985 through March 1999 in 75 hospitals in the greater-Boston and greater-Philadelphia areas. Data on OC use and MI risk factors were obtained by interview from 627 women with a nonfatal first MI (cases) and 2947 female hospital controls younger than 45 years. RESULTS: The overall odds ratio (OR) for current OC use relative to never used was 1.3 (95% confidence interval [CI], 0.8-2. 2). The OR was elevated, 2.5 (95% CI, 0.9-7.5), among heavy smokers (>/=25 cigarettes per day) but close to 1.0 among lighter smokers (OR = 0.8) and nonsmokers (OR = 1.3). For current OC use together with heavy smoking relative to nonuse and nonsmoking, the OR was 32 (95 % CI, 12-81), considerably greater than that for heavy smoking alone, 12 (95% CI, 8.6-16). The ORs did not vary according to the type of formulation or the dose of estrogen; there were too few users to assess the new 20-microg preparations. Past OC use was unrelated to risk. CONCLUSION: Current use of low-dose OCs in the United States is unrelated to an increased risk of MI among nonsmokers and light smokers, but users who smoke heavily may be at greatly increased risk.

Adult↗
PubMed2001

Signal generation and clarification: use of case-control data.

Case-control surveillance systems are useful for 'signal' generation, i.e., signaling potential previously unidentified adverse effects of drugs. Two systems currently in operation, the Slone Epidemiology Unit's Case-Control Surveillance and the Birth Defects Study, have monitored drug effects since 1976. With extensive information on the diagnoses and covariates, the systems have the capacity to carry out in-depth analyses in which the outcome measure is more specifically defined and in which confounding is controlled, thus reducing the possibility of false alarms.

Case-Control Studies↗
PubMed2001

Height and breast cancer risk: results from the Black Women's Health Study (United States).

OBJECTIVES: Numerous studies, but not all, have yielded positive associations between adult height and risk of breast cancer. There are few data on black women. We evaluated adult height in relation to breast cancer in data from the Black Women's Health Study, a prospective cohort study of 64,530 African-American women aged 18-69 years at baseline in 1995. METHODS: A total of 910 cases of breast cancer were analyzed: 700 prevalent cases reported at baseline and 210 incident cases that occurred during the first 2 years of follow-up. A comparison group of controls frequency-matched on 5-year category of birth year was chosen from among participants who had not developed breast cancer. Odds ratios (OR) were calculated for various categories of adult height compared to a reference category of height less than or equal to 61 inches (155 cm), with control for current age, age at menarche, and years of education. RESULTS: Increased height was associated with an increased risk of breast cancer overall (p trend = 0.001); the OR for the highest category of height, > 69 inches (175 cm), was 1.6 (95% confidence interval 1.1-2.3). The association was stronger among premenopausal women and women who had less than 16 years of education. Results were similar for prevalent and incident cases. CONCLUSION: The present findings indicate that height is associated with breast cancer risk in African-American women.

Adolescent↗
PubMed2001

Meningomyelocele reconstruction with bilobed flaps.

A new method for the repair of meningomyeloceles is described. After neurosurgical repair and closure of the placode, the soft-tissue deficit is closed using a bilobed flap. The flap is based superiorly and laterally to the area to be covered. The first lobe crosses the midline above the defect, and the second lobe goes up the midline perpendicular to the first lobe. Once in place, the flap provides a tension-free repair; no suture lines overlie the cord closure.

Female↗
PubMed2001

Clinical and pathological findings in reexcision of incompletely excised basal cell carcinomas.

In common practice, patients with incompletely excised basal cell carcinomas (BCCs) are referred to elective reexcision. In previous reports, it was observed that tumor cells are found in only 50% of the reexcised specimens. The authors performed a retrospective analysis of a large series of patients to evaluate clinical and pathological findings in patients who underwent reexcision of incompletely excised BCCs. A total of 1,478 BCCs arising in 1,278 patients were excised by plastic surgeons in a plastic and reconstructive surgery department during a 4-year period. In 159 patients (10.8%), the excision was incomplete according to the pathological report. These tumors were defined as an incompletely excised BCCs. One hundred of the 159 patients with incompletely excised BCCs (62.9%) were reoperated. Residual tumor cells were found in 28 of 100 patients (28%) within the pathological specimen of the reexcised tissue (defined as positive reexcision, or +veRE). There was no correlation between +veRE and the age or sex of the patient. Location of the BCCs in the cheeks, eyelids, or ears was associated with a low percent of +veRE (10.0%, 13.3%, and 22.2% respectively). Pathological factors associated with a low percent of +veRE were dermal inflammatory infiltrate in the pathological specimen (p = 0.003) and sun damage pathological changes (p = 0.03), but there was no correlation with the pathological subtype distribution of the tumors. The authors conclude that lack of tumor cells at reexcision of incompletely excised BCCs is associated with location of the tumors in the cheeks, eyelids, and ears, and with pathological findings of dermal inflammatory infiltrates or sun damage changes. The roles of inflammatory and solar changes in the destruction of residual carcinoma cells should be investigated further.

Basal Cell Carcinoma↗
PubMed2001

Modulation of JNK and p38 stress activated protein kinases in isolated islets of Langerhans: insulin as an autocrine survival signal.

OBJECTIVE: The objective of this study was to determine the effects of islet isolation and cytokine exposure on e-JUN NH2 terminal kinase (JNK) and p38 activation and whether insulin or the p38 inhibitor PD169316 could modify the response. SUMMARY BACKGROUND DATA: Islet transplantation exposes the cells of the graft to a variety of stressful stimuli that could promote beta-cell death and lead to graft failure. METHODS: Islets from canine (n = 12) and cadaveric human (n = 6) pancreata were isolated and purified. Islets were cultured in CMRL 1066 with and without 100 ng/ml insulin. The response to cytokine stimulation with tumor necrosis factor (TNF)alpha and IL-1 beta and the p38 inhibitor PD169316 was also observed. Islet lysates were analyzed by Western blotting for total and phosphorylated JNK and p38 content. Apoptosis was assessed by TdT-mediated dUTP nick end labeling (TUNEL) assay and by a specific cell death enzyme-linked immunosorbant assay (ELISA). RESULTS: In unstimulated islets, JNK activity was highest immediately following isolation, declining over 3 days to a low baseline level. The activity of p38 was lowest immediately after isolation, increasing progressively with time. The addition of insulin resulted in a more rapid decline in JNK activity, as opposed to p38, which showed no decrease in phosphorylation in response to insulin. In the cytokine stimulation studies, IL-1 beta stimulated p38 activation in a dose dependent manner, while JNK was relatively unaffected. PD169316 (100 microg/ml) was able to inhibit p38 activation in response to the isolation procedure as well as cytokine stimulation. Apoptotic activity was highest 24 hours after isolation, and was significantly reduced when islets were maintained in insulin-supplemented medium. CONCLUSIONS: Inhibition of the stress-activated protein kinase (SAPK) pathways may be important for the maintenance of islet cell survival following islet isolation for transplantation. This study supports an autocrine role of insulin in this process.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Pancreatic cancer: does octreotide offer any promise?

The incidence of adenocarcinoma of the pancreas has risen steadily over the past 4 decades. Since pancreatic cancer is diagnosed at an advanced stage, and because of the lack of effective therapies the prognosis of such patients is extremely poor. Despite advances in our understanding of the molecular biology of pancreatic cancer, the systemic treatment of this disease remains unsatisfactory. Systemic chemotherapy and the administration of biologically active molecules such as tumor necrosis factor or interferons have not resulted in significant improvements in response rates or patient survival. New treatment strategies are obviously needed. This paper will discuss current advances in the use of somatostatin analogs in the management of pancreatic cancer.

Animals↗
PubMed2001

Factors mediating the transdifferentiation of islets of Langerhans to duct epithelial-like structures.

We have previously shown that isolated islets embedded in type 1 collagen gel in the presence of a defined medium undergo transdifferentiation within 96 h to duct epithelial structures. The aim of this study was to identify the factors implicated in this process. Freshly isolated canine islets were embedded in type 1 collagen gel, Matrigel or agarose for up to 120 h and cultured in (i) Dulbecco's modified Eagle's medium (DMEM)/F12 plus cholera toxin (CT), (ii) medium CMRL1066 plus CT, (iii) CMRL1066 plus forskolin and (iv) CMRL1066 alone. At 16 h, intracellular levels of cAMP (fmol/10(3) islets) were increased in groups i-iii (642+/-17, 338+/-48, 1128+/-221) compared with group iv (106+/-19, P<0.01). Epithelial differentiation correlated with the total amount of intracellular cAMP measured over 120 h. Islet-epithelial transformation during the initial 36 h was associated with a wave of apoptosis which was followed by a wave of cell proliferation. During epithelial differentiation there was a progressive loss of all islet hormones and the concomitant expression of cytoskeletal proteins characteristic of duct epithelial cells. Islets in collagen and Matrigel demonstrated high rates of epithelial differentiation (63+/-2% and 71+/-4% respectively) compared with those in agarose gel (0+/-0%, P<0.001). Islets suspended in DMEM/F12 plus CT supplemented with soluble laminin or fibronectin did not undergo transformation. Prior incubation of freshly isolated islets with an integrin-binding arginine-glycine-aspartate motif-presenting synthetic peptide also reduced islet transformation. These studies confirm the biological potential of islets of Langerhans to differentiate to duct epithelial structures. cAMP-mediated signal transduction and an appropriate integrin-matrix interaction are necessary for this process to proceed.

Animals↗
PubMed2001

Redefining critical incidents: a preliminary report.

This pilot study was conducted to describe how some traumatic events become "critical incidents" and to generate a new understanding of the term critical incident. The qualitative research design utilized content analysis of structured interviews of six emergency nurses. The nurses were interviewed regarding the ways they think about certain patient care events, the reasons that specific events are remembered and the changes that occurred following the experience of an event they considered to be critical. The definitions of a critical incident as described in the literature--as an event, as a professional's reaction and as a professional's performance--are included in the nurses' comments. None of them, however, offers a comprehensive way of describing a critical incident. The results of this pilot study suggest one, two or all three elements may be present when a traumatic event is experienced. The interaction of these elements helps to produce a fourth "critical" component, the meaning a nurse gives to an event, which can trigger cognitive, affective and/or behavioral changes. This study acknowledges the importance of all the definitions of a critical incident and proposes a more comprehensive definition that results from the interaction among the other components and the generation of personal meaning and change.

Crisis Intervention↗
PubMed2000

Phosphatidylinositol 3-kinase signaling to Akt mediates survival in isolated canine islets of Langerhans.

The isolation of islet cells from the pancreas by enzymatic digestion causes many of these cells to undergo apoptosis. The aim of this work was to investigate the role of phosphatidylinositol 3-kinase (PI3-K)/Akt signaling in mediating the survival of isolated islets. Insulin-like growth factor-1 (IGF-I) was examined as a potential culture media supplement that could rescue isolated islets from their apoptotic fate. Western blot analysis demonstrated that Akt phosphorylation peaks 20 h after routine islet isolation. PI3-K inhibition with wortmannin abolished both basal and IGF-I-mediated Akt phosphorylation. IGF-I did not increase survival of isolated islets under normal conditions but it did have a protective effect against cytokine (TNF-alpha, IL-1beta, INF-gamma)-mediated cell death. The protective effect of IGF-I against cytokine-stimulated apoptosis was blocked by wortmannin. In addition, inhibition of basal levels of PI3-K activity caused a 31% decrease in islet survival, as shown by MTT assay. These results demonstrate that the PI3-K/Akt pathway mediates survival of isolated islets of Langerhans.

Androstadienes↗
PubMed2000

Charged-particle multiplicity near midrapidity in central Au+Au collisions at sqrt[SNN]=56 and 130 GeV.

We present the first measurement of pseudorapidity densities of primary charged particles near midrapidity in Au+Au collisions at sqrt[s(NN)] = 56 and 130 GeV. For the most central collisions, we find the charged-particle pseudorapidity density to be dN/deta|(|eta|<1) = 408+/-12(stat)+/-30(syst) at 56 GeV and 555+/-12(stat)+/-35(syst) at 130 GeV, values that are higher than any previously observed in nuclear collisions. Compared to proton-antiproton collisions, our data show an increase in the pseudorapidity density per participant by more than 40% at the higher energy.

Journal Article↗
PubMed2000

Risk of breast cancer in relation to the use of injectable progestogen contraceptives and combined estrogen/progestogen contraceptives.

Recent studies have suggested that progestogen-only contraceptives and combined estrogen/progestogen oral contraceptives (COCs) may increase the risk of breast cancer among women less than 35 years of age or among recent users. The authors conducted a case-control study, in which cases of breast cancer (n = 484) [corrected] and controls (n = 1,625) hospitalized for conditions unrelated to contraceptive use were interviewed from 1994 to 1997 in hospitals in greater Cape Town, South Africa. The women were aged 20-54 years, resided in a defined area around Cape Town, and were Black or of mixed racial descent. The relative risk for exposure to injectable progestogen contraceptives (IPCs), mostly depot medroxyprogesterone acetate, was 0.9 (95% confidence interval (CI) 0.7, 1.2). There were no consistent associations within categories of age or recency or duration of use. For exposure to COCs, the overall relative risk was 1.2 (95% CI 1.0, 1.5). Among women below age 35 years, the relative risk was 1.7 (95% CI 1.0, 3.0), and it was unrelated to the duration or recency of use. The findings suggest that IPCs do not increase the risk of breast cancer, and that COCs may increase the risk among women below age 35 years, although bias cannot be excluded.

Adult↗
PubMed2000

Hydrolysed casein diet protects BB rats from developing diabetes by promoting islet neogenesis.

Feeding diabetes-prone BioBreeding (BBdp) rats a hydrolysed-casein (HC)-based semi-purified diet results in two-to-three-fold fewer diabetes cases compared with feeding cereal-based diets such as NIH-07 (NIH). We showed previously that young NIH-fed BBdp rats had decreased islet area at a time when classic insulitis was minimal. Rats fed an HC diet maintained near normal islet area followed 3-4 weeks later by a deviation of the pancreas cytokine pattern from Th1 to Th2/Th3. This finding raised the possibility that BBdp rats were more susceptible to diet-induced changes in islet homeostasis. To investigate this possibility further, BBdp rats were fed an NIH or HC diet from days 23 to 45. Bouin's fixed sections of pancreas were stained with H & E or antibodies for insulin and glucagon. Cell proliferation nuclear antigen (PCNA) was used as a marker of cell proliferation and cells were stained for putative markers of islet neogenesis, cytokeratin 20 (CK20) and Bcl-2. Apoptotic bodies were recognized by morphological features and by TUNEL-positive staining. BBdp rats fed an HC diet had a significantly higher beta-cell fraction than rats fed NIH, whereas alpha-cell fraction and beta-cell size were not affected by diet or rat type. Apoptotic bodies of beta-cells were rare and unaffected by diet. The number of PCNA(+)beta-cells was not affected by diet. CK20 expression was localized in the ductular system and at the periphery of islets in rats aged 7 and 45 days. There were more CK20(+)islets in BBdp rats fed NIH than in those fed HC but the CK20 area fraction was unaffected by diet. Bcl-2 expression was scattered among ducts and central acinar cells. The number of extra-islet insulin(+)and glucagon(+)clusters (<four cells) was significantly higher in animals fed the HC diet compared with those fed NIH. Most of the insulin(+)clusters were also homeodomain-containing transcription factor pancreas duodenum homeobox gene-1 (PDX-1) positive. Glucagon(+)/PDX-1(+)clusters were rarely found. These data are consistent with a shift in pancreas homeostasis that maintains islet cell mass by increased islet neogenesis, a process that was enhanced in animals fed a diabetes-retardant diet.

Animals↗
PubMed2000

Descriptive epidemiology of physical activity in African-American women.

OBJECTIVES: We assessed walking for exercise and moderate and strenuous physical activity in relation to both demographic and health-related characteristics among African-American women from various parts of the United States who participate in the Black Women's Health Study. METHODS: The data were collected in 1995 by mail questionnaire from 64,524 U.S. black women aged 21 to 69 years. The 64,101 women who provided data on physical activity are the subjects of the present report. RESULTS: The present study revealed low levels of physical activity among the African-American women: 57% reported an hour or less per week walking for exercise, 18% reported moderate activity, and 61% reported strenuous physical activity. Strenuous physical activity increased with education. Higher levels of walking for exercise and moderate and strenuous activity were associated with higher levels of participation in strenuous exercise in high school. CONCLUSION: Physical activity levels are low in African-American women. Based on the findings of the present study it may be suggested that educational efforts to increase levels of physical activity should start at an early age.

Adult↗