Incidence of pulmonary embolism in younger versus older patients using CT

OBJECTIVE: The aim of this study is to compare the incidence of pulmonary embolism (PE) on computed tomography (CT) studies between younger and older patients to determine if there is an age-related bias for overutilization of CT pulmonary angiography (CTPA) in younger patients. MATERIAL AND METHODS: Six hundred thirty-one consecutive CTPA cases for suspected acute PE between 11/10/2003 and 3/19/2004 were retrospectively studied. Of these 631 cases, 59 patients were found to have clots in the pulmonary arteries (ranging from central to subsegmental PA). CTPA was performed using multidetector CT at 1.25-mm collimation, 120 kVp, 320 mA. Patients were categorized by gender and age: A, less than 20 (n = 11); B, 20 to 29 (n = 44); C, 30 to 39 (n = 59); D, 40 to 49 (n = 90); E, 50 to 59 (n = 120); F, 60 to 69 (n = 114); G, 70 to 79 (n = 104); H, 80 to 89 (n = 72); I, 90 or more (n = 21). The incidences of PE were calculated in each gender and age group. To compare the incidence of PE between younger and older groups, they were divided into 2 groups at the ages of 40 (<39 and > or = 40), 50 (<49 and > or = 50), and 60 (<59 and > or = 60). Statistical analysis was performed using the chi test. RESULTS: The incidences of PE were 11.9% in males (A, 0%; B, 17.6%; C, 10%; D, 8.3%; E, 13.3%; F, 6.9%; G, 17.5%; H, 23.5%; I, 0%), 7.7% in females (A, 0%; B, 7.4%; C, 5.1%; D, 12.5%; E, 4.2%; F, 14.5%; G, 7.8%; H, 5.5%; I, 0%), and 9.4% in total patients (A, 0%; B, 11.1%; C, 6.8%; D, 11.1%; E, 7.5%; F, 10.5%; G, 11.5%; H, 9.7%; I, 0%). No significant differences in the incidences of PE were observed when patients were divided at the age of 40 (male, female, total; P=1.0, 0.6252, 0.7220), at the age of 50 (male, female, total; P = 0.6748, 0.6879, 1.0), or at the age of 60 (male, female, total; P = 0.8458, 0.7046, 0.6820). CONCLUSION: No statistically significant difference in the incidence of PE was observed between younger and older patients. Our findings suggest that there is no age-related bias for overutilization of CT angiography (CTA) in younger patients.     

CD4(+) cells are indispensable for ulcer development in murine cutaneous leishmaniasis

One of the most characteristic clinical features in cutaneous leishmaniasis is the development of nodules followed by ulcerations at the site of infection. Leishmania amazonensis-infected mice show similar ulcerative lesions. Leishmania-infected severe combined immunodeficiency (SCID) mice, however, have been shown to develop nonulcerative nodules. In the present study, the roles of T cells in ulceration were examined using SCID mice in cell reconstitution experiments. After development of nonulcerative nodules, SCID mice were inoculated with splenocytes from either Leishmania-infected or naive immunocompetent mice, resulting in ulceration in all mice. When naive splenocytes were depleted of CD4(+), CD8(+), or B220(+) cell populations and the remaining cells were injected into Leishmania-infected SCID mice after the development of nodules, only SCID mice inoculated with splenocytes depleted of CD4(+) cells did not show ulceration. The evidence obtained in this study clearly shows that the CD4(+) cell population is indispensable for ulceration in leishmaniasis lesions of SCID mice.     

Phylogenetic relationship of Plasmodium falciparum populations in the Philippines

Malaria is one of the major infectious diseases in the Philippines. It is being targeted for control through sustained early diagnosis, treatment and mosquito control. It is in this light that understanding the genetic background of the parasite population is important not only for basic biology of the organism but also for epidemiology and control of the disease. In the present study, molecular phylogenetic relationships of the 3 Plasmodium falciparum populations in the Philippines with the other populations in the world were inferred based on polymorphisms of 9 highly polymorphic microsatellite DNA loci in the parasite genome. A total of 92 P. falciparum isolates collected from 3 provinces (Kalinga, Palawan and Davao del Norte) in the Philippines, and 8 from other populations (3 African, 2 South American, 2 Papua New Guinean, and 1 Thai) that were previously reported, were used for the analysis. The phylogenetic tree showed that the 3 Philippine populations were genetically divergent from each other as compared to the other populations. The branching pattern of the tree suggests that the 3 Philippine populations were relatively close to the Thai population, rather than the Papua New Guinean populations, indicating that the ancestor of the 3 Philippines populations were introduced from Indochina peninsula, and not from countries located south of the Philippines such as Papua New Guinea or Indonesia.     

Pulmonary hyperpolarized noble gas MRI: Recent advances and perspectives in clinical application

The invention of hyperpolarized (HP) noble gas MRI using helium-3 (³He) or xenon-129 (¹²⁹Xe) has provided a new method to evaluate lung function. Using HP ³He or ¹²⁹Xe for inhalation into the lung air spaces as an MRI contrast agent significantly increases MR signal and makes pulmonary ventilation imaging feasible. This review focuses on important aspects of pulmonary HP noble gas MRI, including the following: (1) functional imaging types, (2) applications for major pulmonary diseases, (3) safety considerations, and (4) future directions. Although it is still challenging to use pulmonary HP noble gas MRI clinically, the technology offers promise for the investigation of the microstructure and function of the lungs.