Heat Capacity of DPPC/Cholesterol Mixtures: Comparison of Single Bilayers with Multibilayers and Simulations.

The excess heat capacity (Δ C ) of mixtures of dipalmitoylphosphatidylcholine (DPPC) and cholesterol (Chol) is examined in detail in large unilamellar vesicles (LUVs), both experimentally, using differential scanning calorimetry (DSC), and theoretically, using a three-state Ising model. The model postulates that DPPC can access three conformational states: gel, liquid-disordered (L), and liquid-ordered (L). The L state, however, is only available if coupled with interaction with an adjacent Chol.

GUVs melt like LUVs: the large heat capacity of MLVs is not due to large size or small curvature.

The excess heat capacity functions (ΔCp) associated with the main phase transition of large unilamellar vesicles (LUVs) and multilamellar vesicles (MLVs) are very different. Two explanations are possible. First, the difference in vesicle size (curvature) results in different gel-fluid interactions in the membrane; those interactions have a large effect on the cooperativity of the phase transition.

Eliminating the roughness in cholesterol's β-face: does it matter?

One of the long-standing issues surrounding cholesterol (Chol) relates to its two-faced character. In particular, the consequences of its having a rough β-face and a smooth α-face on its structural influence in cell membranes has remained elusive. In this study, direct comparisons have been made between cholesterol and a "smoothened" analog, DChol (i.

Energy metabolism and methane production in llamas, sheep and goats fed high- and low-quality grass-based diets.

This study aimed to test whether the digestive and metabolic characteristics of pseudo ruminants provide superior ability to utilise low-quality diets compared to true ruminants. A total of 18 mature, non-pregnant, non-lactating female animals, including six llamas (Lama glama), six Danish Landrace goats and six Shropshire sheep, were used in a crossover design study. The experiment lasted for two periods of three weeks.

Phonological awareness predicts activation patterns for print and speech.

Using fMRI, we explored the relationship between phonological awareness (PA), a measure of metaphonological knowledge of the segmental structure of speech, and brain activation patterns during processing of print and speech in young readers from 6 to 10 years of age. Behavioral measures of PA were positively correlated with activation levels for print relative to speech tokens in superior temporal and occipito-temporal regions. Differences between print-elicited activation levels in superior temporal and inferior frontal sites were also correlated with PA measures with the direction of the correlation depending on stimulus type: positive for pronounceable pseudowords and negative for consonant strings.

[A study of sociocultural factors related to voluntary blood donation in the Americas].

Objective: To obtain baseline data for countries of the Americas on knowledge, attitudes, and practices related to voluntary blood donation as well as on the current level and quality of services that blood banks provide to donors.

Methods: The study was conducted in 15 countries in the Americas: Argentina, Bolivia, Colombia, Costa Rica, Cuba, the Dominican Republic, Ecuador, El Salvador, Guatemala, Jamaica, Nicaragua, Panama, Paraguay, Peru, and Venezuela. Technical cooperation for the study came from the Pan American Health Organization.

Synovial sarcoma of the upper digestive tract: a report of two cases with demonstration of the X;18 translocation by fluorescence in situ hybridization.

Two cases of synovial sarcoma that arose in the upper digestive tract are reported. One case was a polypoid mass that arose at the gastroesophageal junction; the other was a large intramural mass that arose in the wall of the stomach. Both cases had a classic biphasic pattern.

p53 immunostaining of surgical margins as a predictor of local recurrence in squamous cell carcinoma of the oral cavity and oropharynx.

Local and regional recurrence is the principal reason for treatment failure in squamous cell carcinoma (SCC) of the head and neck. The conventional method of evaluating surgical margins for cellular atypia does not always predict risk of local recurrence accurately. Immunostaining of surgical margins for tumor markers may provide a more precise evaluation of risk of local recurrence.

Severe life-threatening cholera associated with blood group O in Peru: implications for the Latin American epidemic.

A household survey in 1991, at the onset of the Latin American cholera epidemic, investigated high attack rates in Trujillo, Peru, and determined the association between blood group O and severe cholera. Of 463 persons in 69 households, 173 (37%) reported diarrhea, 21% required rehydration therapy, and 4% were hospitalized; these treatment requirements greatly exceeded estimates based on other populations. Elevated vibriocidal or antitoxic antibody titers were present in 52% of 321 from whom serum was obtained; 73% were blood group O.

Waterborne transmission of epidemic cholera in Trujillo, Peru: lessons for a continent at risk.

The epidemic of cholera that began in Peru in January, 1991, marked the first such epidemic in South America this century. Subsequently, over 533,000 cases and 4700 deaths have been reported from nineteen countries in that hemisphere. We investigated the epidemic in Trujillo, the second largest city in Peru.

Outbreak of human rabies in the Peruvian jungle.

Transmission of rabies to man by vampire bats has been known for 60 years but there have been few reports of the features of rabies transmitted in this way. These aspects of the disease were investigated during an outbreak in Peru in early 1990. Between Jan 1 and April 30, 1990, 29 (5%) of 636 residents of the two rural communities in the Amazon Jungle in Peru acquired an illness characterised by hydrophobia, fever, and headache and died shortly thereafter.

Malignant myxoid emboli as the presenting feature of primary sarcoma of the aorta (myxoid malignant fibrous histiocytoma): a case report and review of the literature.

Primary sarcomas of the aorta are rare vascular tumors. About 26 cases have been reported between 1973 and 1989. They are seldom diagnosed antemortem.

[Fibroepithelial polyp of the ureter. Report of a new case].

Fibroepithelial polyps are rare benign tumours presenting in one every hundred cases of ureter primitive tumours. Interest on this type of pathology is founded in its low incidence and on being able to reach a pre-operative diagnosis prior to taking surgical action. Uretero-renoscopy is currently the best method available for the identification and histological diagnosis of this polyp.

Prostatic stromal hyperplasia with bizarre nuclei.

Prostatic stromal hyperplasia with bizarre nuclei is an uncommon variant of nodular hyperplasia that may be confused with mesenchymal malignancy but that can usually be distinguished by the degenerative character of the nuclear changes, absent to negligible mitotic rate, and relatively sparse cellularity. We report a case in a 73-year-old man and review six other cases, which, to our knowledge, are the only ones that have been reported previously.

Two unusual manifestations of aortic aneurysms.

Pain and pulsation are common presenting features of aortic aneurysms. Massive hematemasis and ureteral obstruction represent rare clinical presentations. This report describes a patient with massive hematemesis in whom a thoracic aneurysm ruptured into the esophagus, and a second patient in whom a large abdominal aortic aneurysm caused bilateral ureteral obstruction.

Ectopic or heterotopic liver (choristoma) associated with the gallbladder.

A 43-year-old man with a history and symptomatology of hereditary spherocytosis underwent splenectomy and cholecystectomy for treatment of his underlying disease and of cholelithiasis. The removed gallbladder showed a serosal encapsulated nodule, supported by a short mesentery, measuring 11 x 6 x 4 mm, that histologically was an ectopic or heterotopic functioning liver. This nodule did not have any connection with the main liver.

Simple cyst of the rete testis.

We report a case of a simple cyst in the upper pole and connected to the mediastinum testis at the rete testis. The cyst appeared to arise from a dilated rete duct, and it was spherical, smooth-walled and filled with clear fluid. The epithelium was lined with a single layer of cuboidal or flattened cells, with no evidence of squamous differentiation.

Hereditary amyloidosis: description of a new American kindred with late onset cardiomyopathy. Appalachian amyloid.

A family with hereditary amyloidosis characterized by peripheral neuropathy and cardiomyopathy is described. Lack of eye involvement sets their disease apart from the Indiana/Swiss familial amyloidotic polyneuropathy type II. The disease is of late onset; affected members die of cardiomyopathy after age 60.