Pulse blood pressure and cardiovascular mortality in a population-based cohort of elderly Costa Ricans.

UNLABELLED: We studied the relationships between blood pressure (BP), pulse pressure (PP) and cardiovascular (CV) death in older adults using data from 2346 participants enrolled in the Costa Rican CRELES study, mean age 76 years (s.d. 10.2), 31% qualified as wide PP. All covariates included and analyzed were collected prospectively as part of a 4-year home-based follow-up; mortality was tracked for an additional 3 years, identifying 266 CV deaths. Longitudinal data revealed little change over time in systolic BP (SBP), a decline in diastolic BP, and widening of PP. Wide PP was associated with higher risk of CV death but only among individuals receiving antihypertensive drug therapy. Individuals with both wide PP and receiving therapy had 2.6 hazard rate of CV death relative to people with normal-PP plus not taking treatment (TRT), even adjusting for SBP. Increasing PP between visits was significantly associated to higher CV death independently of TRT status. SBP and DBP were not significantly associated to CV death when the effect of PP was controlled for. CONCLUSION: elderly hypertensive patients with wide or increasing PP, especially if receiving TRT, are the highest CV risk group, thus must be carefully assessed, monitored and treated with caution.

Design and manufacture of a novel system to simulate the biomechanics of basic and pitching shoulder motion.

OBJECTIVES: Cadaveric models of the shoulder evaluate discrete motion segments using the glenohumeral joint in isolation over a defined trajectory. The aim of this study was to design, manufacture and validate a robotic system to accurately create three-dimensional movement of the upper body and capture it using high-speed motion cameras. METHODS: In particular, we intended to use the robotic system to simulate the normal throwing motion in an intact cadaver. The robotic system consists of a lower frame (to move the torso) and an upper frame (to move an arm) using seven actuators. The actuators accurately reproduced planned trajectories. The marker setup used for motion capture was able to determine the six degrees of freedom of all involved joints during the planned motion of the end effector. RESULTS: The testing system demonstrated high precision and accuracy based on the expected versus observed displacements of individual axes. The maximum coefficient of variation for displacement of unloaded axes was less than 0.5% for all axes. The expected and observed actual displacements had a high level of correlation with coefficients of determination of 1.0 for all axes. CONCLUSIONS: Given that this system can accurately simulate and track simple and complex motion, there is a new opportunity to study kinematics of the shoulder under normal and pathological conditions in a cadaveric shoulder model.

Changes in core temperature during peritoneal insufflation: comparison of two CO2 humidification devices in pigs.

BACKGROUND: Various modifications of the physical status of CO2 have been used to reduce hypothermia caused by flow of insufflating gas. This animal study aimed to investigate the effects on core temperature, of insufflation with CO2 using two different humidification devices: unheated, humidified CO2 using the Modified-Aeroneb system (Nektar, San Carlos, CA) and warmed, humidified CO2 using the HME-Booster (Medisize, Hillegom, The Netherlands). METHODS: We undertook a prospective four-session study on a homogeneous group of four pigs. After general anesthesia, all animals were treated successively with the following protocols in a randomized order at 8-d intervals: Control (no pneumoperitoneum), Standard (unheated, unhumidified CO2), Modified-Aeroneb (unheated, humidified CO2 by cold nebulization), HME-Booster (heated, humidified CO2). The core temperature of the animals was recorded every 10 min. RESULTS: The temperature decrease is significantly influenced by time (P=0.0001; ANOVA), by the insufflation method (P=0.01), and by the interaction between time and the insufflation method (P=0.0001). The method of contrasts showed the following results:--The temperature decrease in the Standard group and HME-Booster group became greater than in the Control group after 40 min (P=0.02)--The temperature decrease in the Modified-Aeroneb group became greater than in the Control group after 100 min (P=0.04)--The temperature decrease in the Modified-Aeroneb group was less than in the HME-Booster group after 40 min (P=0.04) and less than in the Standard group after 60 min (P=0.01)--The temperature decrease in the Standard group was greater than in the HME-Booster group after 160 min (P=0.005). CONCLUSIONS: Compared with the HME-Booster system, the Modified-Aeroneb is at least as effective in limiting the drop in core temperature during laparoscopic insufflation.

An evaluation of gas humidifying devices as a means of intraperitoneal local anesthetic administration for laparoscopic surgery.

BACKGROUND: Intraperitoneal local anesthetic administration has been reported to provide perioperative analgesia during laparoscopic procedures. The aim of this in vitro study was to assess the efficiency of commercially available humidification devices to deliver ropivacaine and to determine the effects of modifying the device's position between the insufflator and the Veress needle on the amount of ropivacaine delivered. METHODS: In the first experiment, four humidification devices filled with ropivacaine (0.20% and 0.75%) were placed at the outlet of a laparoscopic insufflation system delivering a constant carbon dioxide flow. A catheter was connected to the humidifier's outlet and the other end submerged in a calibrated vial containing 25 mL of 50% methanol in water. The concentration of ropivacaine collected in the methanol-water solution was measured using high performance liquid chromatography. In the second experiment, the clinical situation was imitated by placing 3 m of silicone tubing between the humidifier and the collection vial to evaluate its influence on the amount of ropivacaine delivered. Only one humidifier was tested in the second experiment because the other three tested humidification devices did not efficiently deliver ropivacaine. RESULTS: The evaporation-based humidifiers delivered very small or nonmeasurable quantities of ropivacaine. In contrast, the microvibration-based aerosol humidification device delivered significant amounts (89.1%-94.3%) of the drug. The insertion of silicone tubing between the humidifier and the collecting vial reduced the amount of delivered ropivacaine to 62.3%. CONCLUSIONS: The microvibration-based aerosol humidification device may be used to deliver local anesthetics during laparoscopic procedures. Further research is necessary to confirm these results in clinical practice and to provide effective humidification that does not blur the surgeon's view.

Ultrasonographic control of the puncture level for lumbar neuraxial block in obstetric anaesthesia.

BACKGROUND: Errors in the judgement of puncture level during neuraxial anaesthesia can lead to significant complications. The aim of this study was to assess, in obstetric anaesthesia, the accuracy of clinical determination of the lumbar spinal interspace level, using surface ultrasound imaging as control. METHODS: At the anaesthesia follow-up visit, women who had received lumbar neuraxial anaesthesia during labour were prospectively included. The intervertebral level of needle insertion, located by the needle scar position, was identified by ultrasonography and compared with the clinical level reported on the chart by the anaesthetist who performed the block. RESULTS: Ninety-nine women were studied. The clinical puncture level was accurate in 36.4% of patients. Ultrasound examination showed the puncture level to be more cephalad than the level noted in the anaesthetic record in almost 50% of patients. In 15% of patients, the puncture level was more caudad than the anaesthetist had assessed. Factors including type of anaesthesia, indication, time period, level of anaesthetic experience, BMI, and spinal pathology did not seem to influence the frequency of errors. CONCLUSIONS: The observed differences between clinical and ultrasonic identification of spinal puncture level highlight the potential for serious complications associated with the performance of neuraxial blocks above the spinous process of L3 in the parturient. With the increase in popularity of techniques involving puncture of the dura mater for labour anaesthesia, we feel that awareness of this risk is important.

Factors related to quality of life in breast cancer patients receiving chemotherapy.

This descriptive correlation study investigated the relationship among individual characteristics, disease characteristics, psychological factors (anxiety, depression, self-esteem), social support, and quality of life in patients with breast cancer receiving chemotherapy. One hundred and fifty women from nine Taipei area hospitals were surveyed with a structured questionnaire. The total quality of life index for breast cancer patients was about average (M = 19.88). The family factor scored highest for importance and satisfaction with quality of life. Patients showed the most dissatisfaction with the health factor. Of the individual characteristics affecting patient quality of life, number of children and social status were statistically significant (p < .05). Of the disease characteristics, the stage of the disease, the commencement of chemotherapy, and the number of chemotherapy treatments were statistically significant (p < .05). The psychological factors were significantly related to patients' quality of life (p < .05). Social support of both relatives and health professionals was significantly related to patients' quality of life (p < .01). Of the four independent variables (individual characteristics, disease characteristics, psychological factors and social support), the most influential factor affecting breast cancer patients' total quality of life was the psychological factor of self-esteem (p < .001). The findings can assist nurses to plan and improve the quality of breast cancer care in terms of understanding the factors affecting patients' quality of life.

Infectious disease transmission and infection-dependent matching.

This paper uses commonly available prevalence estimates to bound future incidence. The bounds rely on restricting the fraction of contacts between individuals of different infection statuses. It is argued that these bounds can be further tightened by restrictions of economic models of infectious disease that imply that uninfected individuals have larger incentives to avoid matching with infected individuals than do the infected individuals themselves. This implies that incidence predictions from canonical models of infectious disease are worst-case upper bounds, with the degree to which they overestimate new cases being monotonically related to this type of infection-dependent matching. Evidence in support of the economic type of infection-dependent matching is presented, by using data on the joint distribution of partners' HIV statuses in a random sample of couples from San Francisco in 1988-1989.

An empirical examination of the implications of assortative matching on the incidence of HIV.

Using data from The San Francisco Home Health Study (SFHHS), this paper analyzes the degree to which the incentives to avoid HIV infection result in infection-dependent (assortative) matching patterns based on HIV status. The incidence implications induced by such matching are compared to infection independent matching, an implicit assumption in canonical models within epidemiology. We estimate that an HIV-positive individual is more than twice as likely as an HIV-negative individual to have an HIV-positive partner, and that this results in a decrease in HIV incidence of about one-third compared to the predictions implied by standard epidemiological models.

Phototherapy of cancer and atheromatous plaque with texaphyrins.

Cancer and cardiovascular disease are the leading causes of death in the western world. Photodynamic therapy (PDT) has demonstrated activity in the treatment of superficial cancerous lesions and as an intraoperative adjunct during surgical debulking. Texaphyrins are pure, synthetic water-soluble macrocycles that localize in both cancerous lesions and atheromatous plaque. Lutetium texaphyrin (PCI-0123) is activated by tissue-penetrating far red light (720-760 nm). Patient diagnosis and treatment planning is possible via magnetic resonance imaging (MRI) with the paramagnetic gadolinium texaphyrin (PCI-0120) or via fluorescence imaging using the diamagnetic PCI-0123. In this study it is shown that texaphyrins localize selectively in cancer and atheromatous plaque. PDT with PCI-0123 is found to cause selective photodamage to the diseased tissue. Specifically, PCI-0123 acts to eradicate the SMT-F murine mammary tumors and diet-induced atheromatous plaque in rabbits.

Lutetium texaphyrin (PCI-0123): a near-infrared, water-soluble photosensitizer.

Lutetium texaphyrin, PCI-0123, is a pure, water-soluble photosensitizer with a large broad absorption band centered at 732 nm. The compound was tested for photodynamic therapy (PDT) effectiveness in a murine mammary cancer model. The texaphyrin macrocycle as illustrated by magnetic resonance imaging and 14C-radiolabeled texaphyrin studies was shown to be tumor selective; a tumor-to-muscle ratio of 10.55 was seen after 5 h. Lutetium texaphyrin, at a drug dose of 20 mumol/kg with irradiation 5 h postinjection at 150 J/cm2 and 150 mW/cm2, had significant efficacy (P < 0.0001) in treating neoplasms of moderate size (40 +/- 14 mm3) and also had significant efficacy (P < 0.0001) in treating larger neoplasms (147 +/- 68 mm3). The PDT efficacy was correlated with the time interval between PCI-0123 administration and light exposure. A 100% cure rate was achieved when photoirradiation took place 3 h postinjection compared to 50% for 5 h using 10 mumol/kg and 150 J/cm2 at 150 mW/cm2. The PDT efficacy was attributable to the selective uptake/retention of the texaphyrin photosensitizer in addition to the depth of light penetration achievable at the 732 nm laser irradiation.

Gadolinium(III) texaphyrin: a tumor selective radiation sensitizer that is detectable by MRI.

Gadolinium(III) texaphyrin (Gd-tex2+) is representative of a new class of radiation sensitizers detectable by magnetic resonance imaging (MRI). This porphyrin-like complex has a high electron affinity [E1/2 (red.) approximately = -0.08 V versus normal hydrogen electrode] and forms a long-lived pi-radical cation upon exposure to hydrated electrons, reducing ketyl radicals, or superoxide ions. Consistent with these chemical findings, Gd-tex2+ was found to be an efficient radiation sensitizer in studies carried out with HT29 cells in in vitro as well as in in vivo single and multifraction irradiation studies with a murine mammary carcinoma model. Selective localization of Gd-tex2+ in tumors was confirmed by MRI scanning.

Gadolinium zeolite as an oral contrast agent for magnetic resonance imaging.

The purpose of this study was to evaluate efficacy and safety of a gadolinium (Gd) zeolite suspension as an oral MRI contrast agent. Serial dilutions of GADO-LITE Oral Suspension 1,2-300 micrograms of Gd(III)/mL) were prepared. MRI (T1 and T2 weighted) of standards and dogs (precontrast and postcontrast) were performed. Toxicity and Gd absorption were also assessed. Subsequently, 30 normal male adult volunteers were divided into six groups of five subjects each. Gd zeolite po suspension was administered before and after MRI in volumes and concentrations ranging from 250 to 1500 mL; 6 to 60 micrograms of Gd+3/mL. The images were rated (efficacy score) by a blinded reader. Vital signs, blood chemistries and urinalysis were recorded. Gadolite Oral Suspension produced excellent enhancement of the dog gastrointestinal (GI) tract. No toxicity or absorption of Gd was observed in dogs receiving doses up to 4 times the anticipated human dose daily for 14 consecutive days. In clinical trials, Gd zeolite significantly improved the efficacy scores for all groups and all pulsing sequences (all P values < .05). Efficacy scores and signal intensities generally increased with concentration and volume. No Gd was detected in blood or urine specimens. No significant adverse events were reported. Gd zeolite is a promising contrast medium for enhancement of the GI tract in MRI.

Preclinical evaluation of gadolinium (III) texaphyrin complex. A new paramagnetic contrast agent for magnetic resonance imaging.

RATIONALE AND OBJECTIVES: Gadolinium III texaphyrin (Gd[III] texaphyrin) complex, a new magnetic resonance imaging contrast (MRI) agent, was evaluated. METHODS: In vitro relaxivity (1.5 T) and stability studies (5% dextrose) were conducted. Subchronic toxicity (8 males, 8 females; 2-20 mumol Gd(III) texaphyrin complex/kg body weight; 3 times per week for 3 weeks). Biodistribution and excretion studies were conducted in Sprague-Dawley rats; MRI studies were conducted in normal and tumor-bearing rats and rabbits. RESULTS: Relaxivity values were as follows: r1 = 19 (mumol/L.sec)-1 and r2 = 22 (mumol/L.sec)-1. The 21-day subchronic toxicity study revealed no abnormalities. The compound is stable. Biodistribution demonstrated liver uptake. Magnetic resonance imaging in normal (n = 34) and tumor-bearing (n = 4) rats and normal (n = 8) and tumor-bearing (n = 19) rabbits revealed: significant (P < .05) contrast enhancement of liver and kidney after 1-17 mumol/kg of Gd(III) texaphyrin complex. Gadolinium (III) texaphyrin complex (2.5 mumol/kg) produced significant contrast enhancement of liver carcinomas in rabbits (n = 8). Thigh V2 carcinomas (n = 22) had selective (P < .05) enhancement, 5 mumol/kg. In rat fibrosarcomas (n = 4), 17 mumol Gd(III) texaphyrin complex produced significant enhancement up to 24 hours. CONCLUSIONS: Gadolinium (III) texaphyrin complex appears to be an effective and safe MRI contrast agent.

Marine 4-methyl sterols: synthesis of C-24 epimers of 4 alpha, 24-dimethyl-5 alpha-cholestan-3 beta-ol and 360 MHz 1HNMR comparisons to the natural product from Plexaura homomalla.

Comparison of the highfield 1HNMR spectrum of 4 alpha, 24-dimethyl-5 alpha-cholestan-3 beta-o1 isolated by open column adsorptive chromatography and reversed-phase HPLC from P. homomalla with those of the corresponding synthetic 24 alpha and 24 beta compounds demonstrate that the gorgonian natural product is purely 24 beta, the same C-24 configuration found in sterols related to dinosterol and gorgosterol. 360 MHz 1HNMR data are also reported for synthetic 4 alpha, 24 beta-dimethyl-5 alpha-cholest-22E-en-3 beta-o1 (another P. homomalla natural product). The use of 1HNMR correlations in assigning C-24 configurations of 24-methyl marine sterols possessing various nuclei is examined and discussed. Analyses of the methyl sterol components of P. homomalla are tabulated and discussed with regard to origin and plausible biosynthetic interrelationships in light of the C-24 configurational findings.