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Paul Simon

Publications and source records attributed to Paul Simon.

34 records · Page 2Linked to original sources
PubMed2004

Varicella-related mortality in California, 1988-2000.

BACKGROUND: Although surveillance for varicella in the United States has documented a reduction in cases since vaccine licensure in 1995, information is lacking on varicella-related mortality since vaccine introduction. This study identifies varicella-related mortality in California before and after vaccine introduction and assesses how high risk conditions and complications contributed to varicella deaths during this period. METHODS: California death records mentioning varicella as either an underlying or contributing cause of death were selected from the 1988-2000 multiple cause-of-death files. Pre- and postvaccine periods were compared to assess differences in varicella mortality before and after vaccine introduction. Differences in varicella mortality by age, race/ethnicity and gender were also examined. ICD codes were used to identify high risk conditions and varicella-related complications. RESULTS: A total of 228 varicella-related deaths were reported between 1988 and 2000 in California. Age-adjusted varicella mortality rates showed a downward trend during this period, dropping from a high of 0.97 per million in 1990 to a low of 0.22 per million in 1999. The average age-adjusted mortality rate declined from 0.67 per million prevaccine to 0.38 per million postvaccine. Compared with the prevaccine period, the average rate of decline in varicella mortality was greater after vaccine implementation. Infants had the highest mortality rate for the period. At least one immunocompromising condition was present in 38% of varicella-related deaths. Pneumonia was the most commonly reported complication. CONCLUSIONS: Varicella-related mortality declined in California after vaccine implementation, but potentially preventable varicella-related deaths continue to occur.

Adolescent↗
PubMed2004

The oxygen dissociation curve: quantifying the shift.

An oxyhaemoglobin dissociation curve (ODC) quantifies the most important function of red blood cells and that is the affinity for oxygen and its delivery to the tissues. Oxygen affinity for haemoglobin plays a critical role in the delivery of oxygen to the tissues and is changed by shifting to the left or right. A shift to the left implies an increased oxygen affinity and, hence, tighter binding due to the higher oxygen saturation in relation to the pO2. On the other hand, a shift to the right corresponds to a decreased oxygen affinity and easier release of oxygen to the tissues. It is well known that the ODC shifts in response to changes in pH, pCO2 and 2,3 diphosphoglycerate. However, how much the ODC shifts has never been quantified. Arterial and venous blood gases were taken during cardiopulmonary bypass and two indices were used to quantify the shift of the ODC; the p50 shift and the SO2 difference. Arterial blood shifted to the right by 4 +/- 0.1 mmHg at a pH of 7.24 and shifted to the left by -3.5 +/- 0.05 mmHg at a pH of 7.51. The change in arterial saturation was minimal, rising by 0.8% and dropping by -5% and did not correlate to p50 shifting and changes in pH, but demonstrated changes dependent on the concentration of dyshaemoglobins. The venous blood exhibited a greater range of p50 shifting at each pH value. At a pH of 7.24, the p50 shifted to the right by 4.8 +/- 2 mmHg and at a pH of 7.51 the p50 shifted to the left by -4 +/- 1.8 mmHg. Unlike the arterial blood, the change in saturation correlated well to p50 shifting. It is shown here for the first time how much the curve shifts with changes in pH and how this may be used to evaluate treatment strategies.

Arteries↗
PubMed2004

Reconstructed bicuspid aortic valve after 10 years: clinical and echocardiographic follow-up.

BACKGROUND: Sixteen patients (mean age, 30.9 +/- 12.9 years; range, 9-79 years) with incompetent bicuspid aortic valves underwent valve-sparing correction between 1992 and 1995. METHODS: All patients underwent triangular resection of the enlarged leaflet. In addition, 13 patients underwent commissuroplasty. In 3 patients leaflet perforations were corrected with glutaraldehyde-fixed autologous pericardial patch. All patients underwent annual echocardiographic and clinical examinations at our institution. RESULTS: During follow-up 1 patient died of heart failure, and 3 patients underwent reoperations because of valve incompetence or dilatation of the sinus. Two patients underwent reoperation perioperatively. At long-term follow-up (mean, 10.06 +/- 1.01 years) the remaining 10 patients were in New York Heart Association class I. No patient was receiving anticoagulation, and no thromboembolic, bleeding, or endocarditis events were observed in 107.2 cumulative patientyears of follow-up. Mean grade of regurgitation was 0.7 +/- 0.5; mean aortic flow velocity was 2.29 +/- 0.47 m/s. Optimal valvular function led to normal ventricular diameters (left ventricular end systolic diameter, 39.2 +/- 4.3 mm; left ventricular end diastolic diameter, 56.2 +/- 5.9 mm) and normal ventricular function (fractional shortening, 31.5% +/- 0.1%). The dimensions of the aortic root were stable from 1-year to late followup (mean aortic annulus, 27.1 +/- 6.8 mm; sinus of Valsalva, 33.0 +/- 7.1 mm; sinotubular junction, 34.1 +/- 7.7 mm; ascending aorta, 31.6 +/- 7.4 mm). CONCLUSION: In contrast to early follow-up results of 5 reoperations, clinical and echocardiographic results were excellent for 10 patients who had undergone reconstruction of bicuspid incompetent aortic valves, and the patients were in stable condition after 10 years. However, the mode of early failure is unknown. Reconstruction of bicuspid valves is possible in selected patients.

Adolescent↗
PubMed2004

EuroSCORE predicts mid-term outcome after combined valve and coronary bypass surgery.

BACKGROUND AND AIM OF THE STUDY: EuroSCORE is widely used to assess operative risk. Combined cardiac procedures carry increased perioperative mortality, but the influence of preoperative factors on mid-term outcome is not well known for these patients. The study aim was to determine if EuroSCORE risk influences mid-term survival after combined coronary artery bypass grafting (CABG) and valve surgery. METHODS: Follow up (mean 23.7 months) was obtained in 258 consecutive hospital survivors (148 males, 110 females; median age 72.29 years; mean EuroSCORE 7 points) operated on between January 1998 and March 2001. CABG + aortic valve replacement (AVR) was performed in 171 patients, CABG + mitral surgery in 72, and CABG + double valve surgery in 15. Kaplan-Meier estimates were calculated for survival and combined freedom from death and NYHA class III/IV. The Cox regression model was applied to prove the influence of EuroSCORE risk and a number of preoperative and operative variables on mid-term outcome. RESULTS: Thirty patients (11.63%) died during follow up, and 34 (13.17%) were in NYHA class III/IV. Freedom from death and NYHA class III/IV was 89.3%, 74.7% and 55.2% at 12, 24 and 36 months, respectively. The significant predictor for combined death and NYHA class III/IV was EuroSCORE risk (p = 0.0004). In the subgroup of patients with CABG + mitral valve surgery, age was identified as a significant risk factor for death (p = 0.0346), whereas in the subgroup of patients with CABG + AVR EuroSCORE was detected as significant risk factor for combined death and NYHA class III/IV. CONCLUSION: EuroSCORE is an important predictor for poor mid-term outcome after combined CABG and valve surgery.

Age Factors↗
PubMed2003

LaSeTe2-temperature dependent structure investigation and electron holography on a charge-density-wave-hosting compound.

Single crystals of LaSeTe(2) have been prepared by reaction of the elements in a LiCl/RbCl flux at 970 K for seven days. Satellite reflections observed in diffraction experiments indicate the presence of an incommensurate lattice distortion, which is of the charge-density-wave (CDW) type. The modulated structure has been solved from X-ray data at 173, 293, and 373 K. LaSeTe(2) crystallizes in the 3+1-dimensional orthorhombic superspace group Cmcm(00gamma)s00 (No. 63.2) with lattice parameters of a=4.295(1), b=25.371(4), c=4.306(1) A (173 K), a=4.297(1), b=25.408(4), c=4.309(1) A (293 K), and a=4.309(1), b=25.481(6), c=4.321(1) A (373 K). The modulation vector q=(0, 0, 0.288) does not change over the temperature interval. Electron holographic investigations confirm the existence of the modulation and help to visualize the charge-density wave.

Journal Article↗
PubMed2003

Predictors of adverse outcome and transient neurological dysfunction following surgical treatment of acute type A dissections.

Predictors of adverse outcome after replacement of the ascending aorta with resection of the intimal tear and open distal anastomosis were analyzed in 167 patients (109 male, median age 56). Median hypothermic circulatory arrest (HCA) time was 30 minutes (range 12 to 113). Eighty-six patients (pts) had surgery within 24 hours and 81 within 72 hours of symptom onset. Thirty-seven pts had only ascending aortic replacement, 128 had hemiarch repair, and in 2 the entire arch was replaced. The aortic valve was replaced in 37 pts, resuspended in 116, and untouched in 14. Either death or permanent neurological dysfunction was considered an adverse outcome (AO). AO occurred in 30.5% (51/167) of patients overall. Multivariate analysis revealed that the only significant (P<0.05) independent preoperative predictor of AO was hemodynamic instability (OR 6.0). Transient neurological dysfunction (TND) occurred in 19 of 116 patients (16.4%). Significant predictors of TND were increasing age >60 (OR 3.4 and 7.0 in the second and third tertile as compared with the lowest tertile) and coronary heart disease (OR 3.4). Cumulative survival of patients (median follow-up 34 months) was 55% at 1, 49% at 5, and 44% at 8 years, indicating an excessive in-hospital mortality, but excellent long term outcome. Surgical treatment of acute type A dissections is still associated with a high incidence of adverse outcome, but results in excellent long-term survival. Earlier diagnosis, before the development of cardiac tamponade and hemodynamic compromise, is critical to improve the operative salvage rate.

Adolescent↗
PubMed2002

Regularly shaped, single-crystalline ZnO nanorods with Wurtzite structure.

A convenient route at ambient conditions was employed to prepare narrow-dispersed ZnO nanorods in terms of size and morphology. Transmission electron microscopy and X-ray diffraction were used to characterize the structurally uniform and well-proportioned products. The as-prepared specimen exhibits strong ultraviolet exciton emission at 385 nm and disappearance of visible defect emission.

Journal Article↗
PubMed2002

The role of person-to-person transmission in an epidemiologic study of Pneumocystis carinii pneumonia.

OBJECTIVE: Recent laboratory studies suggest that may be transmitted from person-to-person. Recent exposure to persons with pneumonia (PCP) among HIV-infected persons with and without PCP was assessed to evaluate the person-to-person transmission hypothesis. DESIGN: A case-control study design was used. METHODS: In Seattle and Los Angeles, a history of contact with persons with PCP was compared between HIV-infected patients with laboratory-confirmed PCP (n = 209) and HIV-infected patients with no history of PCP (n = 254). RESULTS: No association was found between past exposures to persons with PCP and an increased odds for PCP [odds ratio (OR), 0.6; 95% confidence interval (CI), 0.3-1.1] in the total study group. In addition, no association was observed when the analysis was restricted to cases and controls who were not on adequate PCP prophylaxis in the previous 3 months (OR, 0.7; 95% CI, 0.3-1.5). Most cases in Los Angeles (95%) and Seattle (96%) were not receiving PCP prophylaxis in the 3 months prior to a PCP diagnosis. Many controls in Los Angeles (54%) and Seattle (47%) were also not on prophylaxis. In addition, 23% of the Seattle cases and 42% of the Los Angeles cases were unaware of their HIV infection at the time of their PCP diagnosis. CONCLUSIONS: Although most participants were not on adequate prophylaxis, we found no evidence of person-to-person transmission of Pneumocystis carinii in a population with advanced HIV disease. The difficulty quantifying past exposures to persons with PCP is a limitation of this type of research.

AIDS-Related Opportunistic Infections↗
PubMed2002

V(D)J-mediated translocations in lymphoid neoplasms: a functional assessment of genomic instability by cryptic sites.

Most lymphoid malignancies are initiated by specific chromosomal translocations between immunoglobulin (Ig)/T cell receptor (TCR) gene segments and cellular proto-oncogenes. In many cases, illegitimate V(D)J recombination has been proposed to be involved in the translocation process, but this has never been functionally established. Using extra-chromosomal recombination assays, we determined the ability of several proto-oncogenes to target V(D)J recombination, and assessed the impact of their recombinogenic potential on translocation rates in vivo. Our data support the involvement of 2 distinct mechanisms: translocations involving LMO2, TAL2, and TAL1 in T cell acute lymphoblastic leukemia (T-ALL), are compatible with illegitimate V(D)J recombination between a TCR locus and a proto-oncogene locus bearing a fortuitous but functional recombination site (type 1); in contrast, translocations involving BCL1 and BCL2 in B cell non-Hodgkin's lymphomas (B-NHL), are compatible with a process in which only the IgH locus breaks are mediated by V(D)J recombination (type 2). Most importantly, we show that the t(11;14)(p13;q32) translocation involving LMO2 is present at strikingly high frequency in normal human thymus, and that the recombinogenic potential conferred by the LMO2 cryptic site is directly predictive of the in vivo level of translocation at that locus. These findings provide new insights into the regulation forces acting upon genomic instability in B and T cell tumorigenesis.

Adaptor Proteins, Signal Transducing↗
PubMed2002

Prosthetic replacement of the aorta is a risk factor for aortic root aneurysm development.

BACKGROUND: Noncompliant prostheses are used in aortic replacement. We hypothesized that this leads to increased distension and wall stress in the aortic root because of the loss of ventriculo arterial coupling. METHODS: Pressure relations in the aortic root caused by changes of aortic elasticity simulating prosthetic aortic replacement were tested in a computer model. We then developed an in vitro model using porcine aortas and performed in vivo validation. RESULTS: Findings in vitro and in vivo confirmed the predicted changes of the computer model. Pressure amplitude increased significantly by 17% after prosthetic replacement (p < 0.01). Pressure-time differential (Dp/dt) and dicrotic notch pressure amplitude both increased significantly. Echocardiography demonstrated systolic aortic root distension with percentage area change increasing in vitro from 28.2%+/-9.7% to 35.9%+/-10% (p < 0.05) and in vivo from 13.3%+/-3.1% to 24.3%+/-3.1% (p < 0.0001). Aortic root wall stress increased markedly. CONCLUSIONS: Replacement of the aorta with vascular prostheses causes important negative alterations of hemodynamics and increases in wall stress.

Animals↗
PubMed2002

The On-X prosthetic heart valve at five years.

BACKGROUND: Multicenter clinical trials were conducted in Europe and North America to evaluate the performance of the On-X bileaflet heart valve prosthesis (Medical Carbon Research Institute, Austin, TX). METHODS: A total of 532 patients underwent implantation, 303 for aortic valve replacement (AVR) and 229 for mitral valve replacement (MVR), at 20 centers from September 1996 to July 2001. The study followed the guidelines of the AATS/STS. Mean follow-up was 23 months (total 1024 patient-years; maximum 5 years). Poolability analysis was performed to show the equivalence of the populations. RESULTS: Patients and results were found to be similar and poolable. Freedom from adverse events at 2 years in the study were as follows: thromboembolism, 96.0% for AVR patients and 96.3% for MVR; thrombosis, 100% for AVR and 100% for MVR; bleeding events, 96.6% for AVR and 95.7% for MVR; and overall mortality, 95.2% for AVR and 92.4% for MVR. Median lactate dehydrogenate levels were in the normal range for AVR and MVR patients at all intervals. At 1 year, AVR echocardiographic results for the 19 to 25 valves, respectively, ranged from 1.5 to 2.8 cm2 for effective orifice area and 9.2 to 4.7 mm Hg for mean gradient, and MVR effective orifice area by pressure half-time was 2.8 cm2 and mean gradient was 4.2 mm Hg. CONCLUSIONS: The two trials have given similarly excellent results for the On-X valve.

Adult↗
PubMed2002

Dilatation of the autograft root after the Ross operation.

OBJECTIVE: Structural differences of the pulmonary root may predispose it to progressive dilatation in the systemic circulation after the Ross operation. We identified the incidence and risk factors of pulmonary autograft root dilatation. METHODS: One hundred and seven adult patients (mean age of 36+/-11 years) were followed after the Ross operation since 1991 including an echocardiogram within 3 months of surgery and yearly clinical assessment and echocardiography. The autograft was measured at the maximum diameter of the sinus (SV) and aortic insufficiency (AI) assessed. A SV of >37 mm was considered as root dilatation and the incidence over time was calculated using the Kaplan-Meier method. Clinically relevant dilatation was defined as a root diameter of >42 mm. In addition, we determined the percentage change of the sinus diameter between the early and latest echocardiogram. Furthermore we tested the influence of patient variables and risk factors on dilatation. RESULTS: By 1 year, dilatation was found in 21 patients (20%). The SV was >42 mm in eight patients (7%). By 7 years, only 45% of patients were free of dilatation. Eleven patients (10%) had a SV of >42 mm. Increase in SV was time related and linear. However, 90% of patients showed <25% dilatation during follow-up. Time from operation, early SV diameter, male gender and surgical technique were identified as significant risk factors of dilatation. However, dilatation has not lead to reoperation due to aneurysm formation or development of significant AI. CONCLUSIONS: We conclude that time dependent autograft root dilation occurs but does not cause an increase in AI and need for reoperation up to 7 years. These findings warrant the pursuit of the concept of the Ross operation in young patients who regain excellent functional status and life style without anticoagulation.

Adult↗
PubMed1990

[The determination of trace amounts of protein in solutions containing surface-active substances].

A rapid and sensitive method for protein determination (0.5-16 micrograms) in samples of any volume containing various surfactants in concentration up to 1% is suggested. The method includes the protein acid denaturation, the solution of acid insoluble precipitate of detergent in ethanol (25-30%), the protein determination on nitrocellulose filter, dyeing by aminoblack 10 B, elution of dyed complex and colorimetric determination at 630 nm.

Amido Black↗
PubMedDate not supplied

Sexual behavior and condom practices among Los Angeles women.

BACKGROUND: The sociodemographic correlates of the number of recent sexual partners and condom use are investigated in a population-based sample of 1,178 unmarried women living in Los Angeles County. RESULTS: Asian Americans, foreign born, and older women are less likely to be sexually active and that more educated and previously married women are more likely. Among the sexually active (n = 909), Hispanic women and older women are less likely to have multiple partners, and younger and previously married women more are more likely. African-American women and younger women are more likely to use condoms; older and previously married women are less likely. CONCLUSIONS: Results from this study indicate that women-centered primary and secondary prevention efforts may benefit from targeting women not previously considered, such as women of post-reproductive age and divorced women.

Adult↗
PubMedDate not supplied

A population-based analysis of pneumococcal disease mortality in California, 1989-1998.

OBJECTIVES: Pneumococcal disease is an important cause of vaccine-preventable mortality. It is important to understand the burden and distribution of mortality so that prevention efforts can be targeted appropriately. This study evaluated pneumococcal disease mortality and its demographic correlates in California from 1989 to 1998. METHODS: Deaths due to pneumococcal disease were identified from statewide vital records data using multiple cause-coded information. Denominator data were obtained from estimates from the California Department of Finance. Crude and age-adjusted mortality rates and 95% confidence intervals were calculated for each age, gender, and racial/ethnic group. RESULTS: The age-adjusted pneumococcal disease mortality rate was 2.05 deaths per 100,000 population. Mortality was highest in elderly individuals (reaching 38.29 deaths per 100,000 population in individuals older than age 85). Age-adjusted mortality rates were elevated in the African American race/ethnicity group (2.96 deaths per 100,000 population) and males (2.67 deaths per 100,000 population). The majority of individuals who died of pneumococcal disease (78.9%) fell into at-risk groups indicated for vaccination. The majority of all pneumococcal deaths were caused by pneumococcal pneumonia. Mortality was seasonal, reaching a peak in the winter months. A decreasing trend in mortality was observed over the 10-year period examined. CONCLUSIONS: Pneumococcal disease remains a significant cause of vaccine-preventable mortality in the California population. Greater efforts must be made to vaccinate at-risk individuals, especially those in demographic groups at highest risk of death.

Adolescent↗