Biomedical subjects

M Cushman

Publications and source records attributed to M Cushman.

At least 55 records · Page 3Linked to original sources

PubMed2001

Management of multiple burn casualties in a high volume ED without a verified burn unit.

The objective of the study was to evaluate the effectiveness of triage, treatment, and transfer interventions on multiple burn casualties managed in a high volume ED that does not have a verified in-hospital burn unit. The charts of 11 male patients injured in a 1999 foundry explosion and brought to Baystate Medical Center (BMC), a level I trauma center, were reviewed. All patients sustained deep partial and full thickness burns. The injury severity score (ISS) ranged from 9 to 75. Five patients had total body surface area (TBSA) burns of 10% to 50% and 6 patients had TBSA burns of 70% to 95%. Transfer times from the scene to BMC ranged from less than 5 minutes to 22 minutes. All 11 were initially triaged, resuscitated, and evaluated at BMC. Of the 9 patients transferred to verified burn units, 8 were intubated, 6 of 6 had negative abdominal ultrasounds, 4 had undergone escharatomies, and 1 had undergone bronchoscopy before transfer. Nine critically injured burn patients with ISS of 9 to 75 were transferred from BMC to verified burn units. For 8 of these patients, the average time from triage, evaluation, and treatment to transfer was 2 hours. The ninth patient was initially admitted overnight then promptly transferred after re-evaluation of his hand burns indicated a need for more specialized care. Two of 9 transferred patients, both with ISS of 75 died. Although 7 other patients had prolonged and complex courses, none of their subsequent complications were referable to missed injuries from this transferring facility. The resources and expertise of a high volume ED without an in-hospital burn unit can be effectively used in the initial resuscitation and treatment of multiple burn casualties. Coordinated responses among emergency medicine, trauma, anesthesia, and nursing personnel are instrumental to the rapid triage, resuscitation, and treatment of critically injured burn patients. Future disaster planning should incorporate a clearly demarcated, ED command center led by an easily identifiable "captain of the ship," as well as more accurate patient identification systems and improved communications with family members.

Adult↗

PubMed2001

Influence of hemostatic factors on spontaneous abortion.

To assess the relationship between hemostatic factors and spontaneous abortion, 134 pregnant women presenting to the emergency department were recruited and followed through 22 weeks' gestation. Cases were women experiencing a spontaneous abortion and controls were women who maintained their pregnancy. Fibrinogen, factor VII antigen, activated protein C-sensitivity ratio (APC-SR), protein S, and plasmin-antiplasmin (PAP) were measured. Cases had lower mean levels of fibrinogen and factor VII antigen compared with controls (3.1 g/L vs. 3.7 g/L and 89% of normal vs. 109% of normal, respectively). Regression analyses found that women with fibrinogen levels below 3.0 g/L had a five-fold increased risk of spontaneous abortion (OR = 5.1, 95% CI: 1.8-14.4) and women with factor VII antigen levels below 94% of normal had a threefold increased risk of spontaneous abortion normal (OR = 3.3, 95% CI: 1.2-8.5). Similar mean levels of APC-SR, protein S, and PAP were found in the two groups.

Abortion, Spontaneous↗

PubMed2001

Effects of estrogen and selective estrogen receptor modulators on hemostasis and inflammation: potential differences among drugs.

Postmenopausal hormone replacement therapy (HRT), tamoxifen, and raloxifene all share an increase of about three-fold in the risk of venous thromboembolism (VTE). Currently, it is thought that HRT transiently increases the risk of myocardial infarction (MI), followed by subsequent reduction in risk, at least among women with established coronary heart disease. Raloxifene and tamoxifen are not known to share this apparent clinical effect. Study of hemostasis and inflammation factors, as surrogate end points, can be useful to form hypotheses concerning the pathophysiology related to clinical effects of these agents. Data presented here suggest differences among these agents that might relate to differences in clinical outcomes. From the vascular perspective, future studies need to focus on interactions of treatment with these biochemical parameters and their genetic correlates in order to define low- or high-risk subgroups for intervention with these therapies.

Estrogen Receptor Modulators↗

PubMed2001

Tamoxifen and cardiac risk factors in healthy women: Suggestion of an anti-inflammatory effect.

-Tamoxifen reduces the incidence of breast cancer in women at risk for that disease. Because heart disease is the leading cause of death in women and because tamoxifen is also associated with venous thrombosis, an improved understanding of the association of tamoxifen with cardiovascular disease risk factors is required. In 111 healthy women at a single center, who were participating in a randomized double-blind breast cancer prevention trial, the 6-month effects of oral tamoxifen (20 mg/d) compared with placebo on factors related to inflammation, hemostasis, and lipids were studied. Tamoxifen was associated with reductions of 26% in median C-reactive protein, 22% in median fibrinogen, and 9% in cholesterol (all P:<0.01 compared with placebo). There were no differences in treatment effects on factor VII coagulant activity, fragment 1-2, and triglycerides. In secondary analyses, the effect of tamoxifen on C-reactive protein was larger in postmenopausal women and in women with higher waist-to-hip ratios. The effect on fibrinogen was larger in women with higher baseline cholesterol. Tamoxifen demonstrated effects on inflammatory markers that were consistent with reduced cardiovascular risk. These findings are in contrast to recent reports of increased C-reactive protein associated with postmenopausal estrogen. The potential for beneficial cardiovascular effects of tamoxifen in healthy women is suggested.

Administration, Oral↗

PubMed2001

Hormone replacement therapy is associated with higher FEV1 in elderly women.

Estrogen and progesterone use have been associated with improved pulmonary function in premenopausal women. However, little research has examined the relationship between hormone replacement therapy (HRT) and pulmonary function in postmenopausal women. We examined the relationship of HRT with spirometry in 2,353 women aged 65 yr and older participating in the Cardiovascular Health Study in 1993/1994. Current use of HRT was hypothesized to be associated with higher FEV1, higher FVC, and less pulmonary obstruction (FEV1/FVC < 65%). FEV1 was higher among current HRT users compared to noncurrent users in the following groups: overall (1.82 L versus 1.66 L, p < 0.0001), among women without asthma (1.85 L versus 1.69 L, p < 0.0001), among former smokers (1.76 L versus 1.60 L, p = 0.013), and among never smokers (1.90 L versus 1.72 L, p < 0.0001). Overall, HRT use was associated with a lower prevalence of pulmonary obstruction (OR 0.75 [95% CI 0.55, 0.99]). After controlling for potential confounders, HRT use was significantly associated with higher FEV(1) (p = 0.031) and with a lower prevalence of obstruction (OR 0.67 [95% CI 0.48, 0.95]). We conclude that postmenopausal women who use HRT have higher levels of FEV1 and less obstruction, which could not be explained by their lower rates of smoking and other health factors associated with HRT use.

Aged↗

PubMed2001

Evaluation of very low-dose subcutaneous vitamin K during postoperative warfarin therapy.

STUDY OBJECTIVE: To determine the effect of very low-dose subcutaneous vitamin K (SCVK) compared with withholding warfarin for above-target international normalized ratio (INR) values after joint surgery. DESIGN: Historical controlled study. SETTING: University hospital. SUBJECTS: One hundred thirty-nine patients beginning warfarin after total joint surgery. INTERVENTION: For a high INR, warfarin was either withheld or SCVK 100, 300, or 400 microg was administered, depending on INR value. MEASUREMENTS AND MAIN RESULTS: The primary outcome was change in INR from the day of intervention (day 1) to the next day (day 2). Adjusting for day 1 INR, the mean day 2 INR was 2.10 (95% confidence interval [CI] 1.86-2.33) after SCVK, compared with 2.73 (95% CI 2.50-2.96) in controls. This corresponded to declines of -0.72 and -0.08, respectively (p=0.001). CONCLUSION: In orthopedic patients starting warfarin therapy, very low-dose SCVK was more effective than withholding warfarin in reducing high INRs. Investigations in other populations and assessment of the effect of low-dose SCVK on postoperative bleeding are indicated.

Aged↗

PubMed2001

The relation of markers of inflammation to the development of glucose disorders in the elderly: the Cardiovascular Health Study.

Several studies suggest that inflammation plays a role in the pathogenesis of some glucose disorders in adults. We tested this hypothesis in a longitudinal cohort study of older individuals who had normal fasting glucose (FG) values at baseline. We compared the baseline levels of six inflammatory markers in participants who had developed glucose disorders at follow-up with those of participants whose FG remained normal at follow-up. Participants were members of the Cardiovascular Health Study, a prospective study of risk factors for cardiovascular disease in adults > or =65 years. All 5,888 participants had baseline testing, including FG and markers of inflammation: white blood cell and platelet counts and albumin, fibrinogen, C-reactive protein (CRP), and factor VIIIc levels. At 3-4 years of follow-up, 4,481 (84.5%) of those who were alive had FG levels retested. Participants who developed diabetes (n = 45) had higher median levels of CRP at baseline than those who remained normoglycemic. On multivariate analysis, those with elevated CRP levels (75th percentile [2.86 mg/l] vs. 25th percentile [0.82 mg/l]) were 2.03 times (95% confidence intervals, 1.44-2.86) more likely to have diabetes on follow-up. Adjustment for confounders and other inflammatory markers did not appreciably change this finding. There was no relationship between the development of diabetes and other markers of inflammation. Inflammation, as measured by CRP levels, is associated with the development of diabetes in the elderly. Understanding the role of inflammation in the pathogenesis of glucose disorders in this age-group may lead to better classification and treatment of glucose disorders among them.

Aged↗

PubMed2001

Incidence and predictors of coronary heart disease among older African Americans--the Cardiovascular Health Study.

Although coronary heart disease (CHD) is the leading cause of death and morbidity in older African Americans, relatively little is known about the incidence and predictors of CHD in this population. This study was undertaken to determine the incidence and predictors of CHD in African-American men and women aged 65 years and older. The participants in this study included a total of 924 African-American men and women aged 65 years of age and older who participated in the Cardiovascular Health Study (CHS). The overall CHD incidence was 26.6 per 1,000 person-years of risk. Rates were higher in men than women (35.3 vs. 21.6) and in those 75 years or older than in those less than 75 years (31.3 vs. 24.5). In multivariate analysis, factors associated with higher risk of incident disease were male gender [relative risk (RR) = 1.8, 95% confidence interval (CI) = 1.1, 2.7], diabetes mellitus (RR = 1.9, 95% CI = 1.2, 2.9), total cholesterol (RR for 40 mg/dL increment = 1.3, 95% CI = 1.0, 1.5), and low (i.e., <0.9) ankle-arm index (RR = 2.1, 95% CI = 1.3, 3.4) after adjusting for age. Within this cohort of older African Americans, male gender, diabetes mellitus, total cholesterol, and low ankle-arm index and were independently predictive of incident events. These results suggest that the ankle-arm index, a measure of advanced atherosclerosis, should be further evaluated for its efficacy in identifying older African Americans at risk for incident clinical events.

Black or African American↗

PubMed2000

Anti-HIV activity of a series of cosalane amino acid conjugates.

The binding of the anti-HIV agent cosalane to CD4 is thought to involve ionic interactions of negatively charged carboxylates of the ligand with positively charged residues on the surface of the protein. The purpose of the present study was to examine the hypothesis that the two carboxyl groups of cosalane could be sacrificed through conjugation to amino acids, and the anti-HIV activity still be retained, provided that at least two new carboxyl groups are contributed by the amino acid residues.

Amino Acids↗

PubMed2000

Clustering of procoagulation, inflammation, and fibrinolysis variables with metabolic factors in insulin resistance syndrome.

The known metabolic cardiovascular disease risk factors associated with insulin resistance syndrome (IRS) do not adequately explain the excess cardiovascular disease risk attributed to this syndrome, and abnormalities in hemostatic variables may contribute to this excess risk. Using data from 322 nondiabetic elderly men and women (aged 65-100 years) participating in the Cardiovascular Health Study during 1989-1990, the authors performed factor analysis on 10 metabolic risk factors associated with IRS and 11 procoagulation, inflammation, and fibrinolysis variables to examine the clustering of the metabolic and hemostatic risk markers. Factor analysis of the metabolic variables confirmed four uncorrelated factors: body mass, insulin/glucose, lipids, and blood pressure. Adding the hemostatic variables yielded three new factors interpreted as inflammation, vitamin K-dependent proteins, and procoagulant activity. Plasminogen activator inhibitor-1 clustered with the body mass factor, supporting the hypothesis that obesity is related to impaired fibrinolysis. Fibrinogen clustered with the inflammation summary factor rather than procoagulant activity, supporting the position that fibrinogen principally reflects underlying inflammation rather than procoagulant potential. The authors conclude that should hemostatic variables be shown to contribute to IRS-related cardiovascular disease, apart from plasminogen activator inhibitor-1, they may do so independently of the established metabolic abnormalities.

Aged↗

PubMed2000

Depressive symptoms and risks of coronary heart disease and mortality in elderly Americans. Cardiovascular Health Study Collaborative Research Group.

BACKGROUND: Several epidemiological studies have associated depressive symptoms with cardiovascular disease. We investigated whether depressive symptoms constituted a risk for coronary heart disease (CHD) and total mortality among an apparently healthy elderly cohort. METHODS AND RESULTS: In a prospective cohort of 5888 elderly Americans (>/=65 years) who were enrolled in the Cardiovascular Health Study, 4493 participants who were free of cardiovascular disease at baseline provided annual information on their depressive status, which was assessed using the Depression Scale of the Center for Epidemiological Studies. These 4493 subjects were followed for 6 years for the development of CHD and mortality. The cumulative mean depression score was assessed for each participant up to the time of event (maximum 6-year follow-up). Using time-dependent, proportional-hazards models, the unadjusted hazard ratio associated with every 5-unit increase in mean depression score for the development of CHD was 1.15 (P:=0.006); the ratio for all-cause mortality was 1.29 (P:<0.0001). In multivariate analyses adjusted for age, race, sex, education, diabetes, hypertension, cigarette smoking, total cholesterol, triglyceride level, congestive heart failure, and physical inactivity, the hazard ratio for CHD was 1.15 (P:=0.006) and that for all-cause mortality was 1.16 (P:=0.006). Among participants with the highest cumulative mean depression scores, the risk of CHD increased by 40% and risk of death by 60% compared with those who had the lowest mean scores. CONCLUSIONS: Among elderly Americans, depressive symptoms constitute an independent risk factor for the development of CHD and total mortality.

Aged↗

PubMed2000

Synthesis of new indeno[1,2-c]isoquinolines: cytotoxic non-camptothecin topoisomerase I inhibitors.

In an attempt to design and synthesize potential anticancer agents acting by inhibition of topoisomerase I (top1), a new series of indenoisoquinolines was prepared and tested for cytotoxicity in human cancer cell cultures and for activity against top1. The synthesis relied on the condensation of substituted Schiff bases with homophthalic anhydrides to produce cis-3-aryl-4-carboxyisoquinolones that were cyclized to indenoisoquinolines in the presence of thionyl chloride. Both top1 inhibitory activity and cytotoxicity maximized in a single compound, 6-[3-(2-hydroxyethyl)aminopropyl]-5,6-dihydro-2,3-dimethoxy-8, 9-methylenedioxy-5,11-dioxo-11H-indeno[1,2-c]isoquinoline hydrochloride (19a), which proved to be a very potent top1 inhibitor having a 110 nM mean graph midpoint (MGM) when tested for cytotoxicity in 55 human cancer cell cultures. A number of structurally related indenoisoquinolines were also obtained that had both potent cytotoxicity as well as top1 inhibitory activity. The key feature of the more potent compounds was the presence of an aminoalkyl side chain on the indenoisoquinoline nitrogen atom. The DNA cleavage patterns induced by top1 in the presence of the indenoisoquinolines were different from those seen with camptothecin. Some of the cleavage sites induced by the indenoisoquinolines were different from those seen with camptothecin, and conversely, camptothecin induced unique cleavage sites not apparent with the indenoisoquinolines. However, both camptothecin and the indenoisoquinolines also induced DNA cleavage sites that were the same in both series but varied in intensity. In addition, some of the DNA cleavages seen with the free base of 19a (compound 18c) in the presence of top1 were inhibited at higher drug concentrations, suggesting either a direct inhibition of the enzyme or an alternative mechanism involving DNA intercalation. Consistent with intercalation, compound 18c did unwind DNA.

Antineoplastic Agents↗

PubMed2000

Identification of optimal anion spacing for anti-HIV activity in a series of cosalane tetracarboxylates.

The binding of the anti-HIV agent cosalane to CD4 is thought to involve ionic interactions of negatively charged carboxylates of the ligand with positively charged residues on the surface of the protein. An investigation of the optimal anion distances for anti-HIV activity in a series of cosalane tetracarboxylate analogues has been completed, and maximal activity results when the two proximal and the two distal carboxylates are separated by eight atoms.

Anti-HIV Agents↗

PubMed2000

Synthesis of B-ring homologated estradiol analogues that modulate tubulin polymerization and microtubule stability.

2-Methoxyestradiol is a cytotoxic human metabolite of estradiol with the ability to bind to the colchicine site of tubulin and inhibit its polymerization, and its 2-ethoxy analogue is even more potent. On the basis of a hypothetical relationship between the structures of colchicine and 2-methoxyestradiol, a B-ring-expanded 2-ethoxyestradiol analogue was synthesized in which the B-ring of the steroid is replaced by the B-ring of colchicine. The synthesis relied on the B-ring expansion of available 6-keto estradiol derivatives as opposed to a total synthesis of the homologated steroid framework. The relative configurations of the acetamido substituents in both epimers of the final product were determined by NOESY NMR and confirmed by X-ray crystallography. The epimer having the 6alpha-acetamido substituent was more active as an inhibitor of tubulin polymerization, and it was also more cytotoxic than the 6beta-epimer. These results are consistent with the proposed structural resemblance of 2-methoxyestradiol and colchicine. Several of the synthetic intermediates proved to be potent inhibitors of tubulin polymerization. On the other hand, a 3,17beta-diacetylated, B-ring-expanded analogue of 2-ethoxyestradiol having a ketone at C-6 resembled paclitaxel (Taxol) in its ability to enhance tubulin polymerization and stabilize microtubules. The corresponding 3-acetate and the 17beta-acetate were both synthesized, and it was determined that the 17beta-acetate, but not the 3-acetate, conferred on the steroid derivative its paclitaxel-like activity.

Animals↗

PubMed2000

The atomic structure of pentameric lumazine synthase from Saccharomyces cerevisiae at 1.85 A resolution reveals the binding mode of a phosphonate intermediate analogue.

Lumazine synthase of Saccharomyces cerevisiae is a homopentamer with a molecular weight of 90 kDa. Crystals of the recombinant enzyme with a size of up to 1.6 mm were obtained. The space group is P4(1)2(1)2 with lattice dimensions 82.9 A x 82.9 A x 300.2 A. X-ray diffraction data collected under cryogenic conditions were complete to 1.85 A resolution. The structure of the enzyme in complex with the intermediate analogue, 5-(6-D-ribitylamino-2,4-dihydroxypyrimidine-5-yl)-1-pentyl-p hosphonic acid was solved via molecular replacement using the structure of the Bacillus subtilis enzyme as search model and was refined to a final R-factor of 19.8% (Rfree: 22.5%). The conformation of the active site ligand of the enzyme mimicks that of the Schiff base intermediate of the enzyme-catalyzed reaction. The data enable the reconstruction of the reactant topology during the early steps of the catalytic reaction. Structural determinants, which are likely to be responsible for the inability of the S. cerevisiae enzyme to form icosahedral capsids, will be discussed.

Amino Acid Sequence↗

PubMed2000

Synthesis and anti-HIV activity of cosalane analogues incorporating nitrogen in the linker chain.

Introduction of an amido group or an amino moiety into the alkenyl linker chain of cosalane (1) provided a new series of analogues 3-8. The new compounds were evaluated as inhibitors of the cytopathic effect of HIV-1 and HIV-2 in cell culture. The replacement of the 1' and 2' carbons in the linker chain of I by an amido group was generally tolerated. The length of the linker chain and the stereochemistry of the substituent at C-3 of the steroidal ring had significant effects on the antiviral activity and potency. Incorporation of an amino moiety into the linker completely abolished the anti-HIV activity. There are several steps in the HIV replication cycle that have been proposed as targets for the development of therapeutic agents (De Clercq, E. J. Med. Chem. 1995, 38, 2491; De Clercq, E. Pure Appl. Chem. 1998, 70, 567). However, currently approved anti-HIV drugs are only directed against the viral enzymes reverse transcriptase or protease (Carpenter. C. C. J.; Fischl, M. A.; Hammer, S. M.; Hirsch, M. S.; Jacobsen, D. M.; Katzenstein, D. A.; Montaner, J. S. G.; Richman, D. D.; Saag, M. S.; Schooley, R. T.; Thompson, M. A.; Vella, S.; Yeni, P. G.; Volberding, P. A. JAMA 1998, 280, 78). Drugs capable of interfering with other steps of the virus life cycle will be highly valuable in the antiretroviral therapy of AIDS, as they will have different patterns of resistance mutations than the drugs currently used clinically. In addition, their utilization in combination with other therapeutic agents could provide more potent drug 'cocktails' capable of completely suppressing virus replication. Consequently, there is an urgent need for the discovery of clinically useful anti-HIV agents possessing novel mechanisms of action.

Anti-HIV Agents↗

PubMed2000

Case studies in heparin-induced thrombocytopenia.

Type II heparin-induced thrombocytopenia (HIT) is an immunological disorder characterized by antibodies to heparin-platelet factor 4 complexes and a high risk of thrombotic complications. Here, we present illustrative case histories to educate the reader on evaluation and management of this complex syndrome. Cases include typical and unusual presentations of the syndrome, and commonly encountered problems and pitfalls of therapy. Major points illustrated are, (1) occurrence of HIT with any dose or form of heparin; (2) misperceptions on the diagnostic criteria; (3) correct (thrombin inhibitors) and incorrect (platelet transfusions and warfarin) management; (4) influence of management strategy on clinical outcomes; (5) severity of the syndrome; and (6) potential for both anamnestic response to heparin and disappearance of HIT antibodies over time. Effective therapy of HIT involves both the prompt recognition of the syndrome and its proper management.

Aged↗

PubMed2000

A steroid derivative with paclitaxel-like effects on tubulin polymerization.

The endogenous estrogen metabolite 2-methoxyestradiol has modest antimitotic activity that may result from a weak interaction at the colchicine binding site of tubulin, but it nevertheless has in vivo antitumor activity. Synthetic efforts to improve activity led to compounds that increased inhibitory effects on cell growth, tubulin polymerization, and binding of colchicine to tubulin. This earlier work was directed at modifications in the steroid A ring, which is probably analogous to the colchicine tropolonic C ring. One of the most active analogs prepared was 2-ethoxyestradiol (2EE). We report here that different modifications in the steroid B ring of 2EE yield compounds with two apparently distinct modes of action. Simple expansion of the B ring to seven members resulted in a compound comparable to 2EE in its ability to inhibit tubulin polymerization and colchicine binding to tubulin. Acetylation of the hydroxyl groups in this analog and in 2EE essentially abolished these inhibitory properties. The introduction of a ketone functionality at C6, together with acetylation of the hydroxyls at positions 3 and 17, produced a compound with activity similar to that of paclitaxel, in that the agent enhanced tubulin polymerization into polymers that were partially stable at 0 degrees C. The acetyl group at C17, but not that at C3, was essential for this paclitaxel-like activity.

2-Methoxyestradiol↗