Review of animal models in carotenoid research

Foods containing provitamin A carotenoids are the primary source of vitamin A in many countries, despite the poor bioavailability of carotenoids. In addition, epidemiologic studies suggest that dietary intake of carotenoids influences the risk for certain types of cancer, cardiovascular disease and other chronic diseases. Although it would be ideal to use humans directly to answer critical questions regarding carotenoid absorption, metabolism and effects on disease progression, appropriate animal models offer many advantages. This paper will review recent progress in the development of animal models with which to study this class of nutrients. Each potential model has strengths and weaknesses. Like humans, gerbils, ferrets and preruminant calves all absorb beta-carotene (betaC) intact, but only gerbils and calves convert betaC to vitamin A with efficiency similar to that of humans. Mice and rats efficiently convert betaC to vitamin A but absorb carotenoids intact only when they are provided in the diet at supraphysiologic levels. Mice, rats and ferrets can be used to study cancer, whereas primates and gerbils are probably more appropriate for studies on biomarkers of heart disease. No one animal model completely mimics human absorption and metabolism of carotenoids; thus the best model must be chosen with consideration of the specific application being studied, characteristics of the model, and the available funding and facilities.     

Congenital pulmonary atresia with ventricular septal defect: angiographic and surgical correlates

Of 181 patients with severe congenital pulmonary atresia and ventricular septal defect or "type IV truncus" (an obsolete term), all but 11% had true central pulmonary arteries. These arteries were demonstrable by large serial biplane angiograms using multiple selective injections into collateral vessels, frequent photographic subtraction, and occasional pulmonary vein-wedge angiograms. These techniques are extremely important for accurate diagnosis and in planning corrective or palliative surgery, which was done in 77% of patients with pulmonary arteries.     

Laughter therapy for patients with cancer.

Humor is an important part of life. Care should be taken to ensure that humor persists even during the bleakest times for patients, families, and medical personnel. Laughter eases the mind, defuses tension among people, and has positive physiologic effects on patients. Facilitated nursing intervention with humor helps to inject this important facet of life into difficult scenes. One successful approach to introducing humor into the hospital setting is a hall-roving "Laugh Mobile." Its humorous novelties, books, and films help divert the attention of suffering patients to lighter thoughts.     

A MRI gradient waveform model for automated sequence calibration.

In order to set up magnetic resonance imaging (MRI) procedures of arbitrary voxel dimensions, slice orientation, and sequence timing in a reasonable time, some form of automatic gradient pulse calibration is required. One such method, involving simulation of gradient waveforms, is presented. Waveforms are modeled based on measurements of the step response. The model used divides each transition into three time regions: a "start" region in the first 0.3 ms, a "slew" region, and a "tail" region representing decay of the eddy current compensation error. In the "slew" region, the time derivative of the gradient, G' (t), is expressed as a function of G(t). The first two regions are nonlinear with respect to demand. The mean error in the simulated gradient is generally less than 0.04 mT m-1 in spin echo sequences. Image signal/noise ratios resulting from sequences calibrated using the model are within 5% of those of empirically calibrated sequences.     

Plasma and dietary carotenoids, and the risk of prostate cancer: a nested case-control study.

The association between plasma carotenoids and prostate cancer risk was investigated in a case-control study nested within the prospective Health Professionals Follow-up Study. We matched 450 incident prostate cancer cases diagnosed from 1993-1998 to 450 controls by age, time, month, and year of blood donation. Modest inverse, but not statistically significant, associations were observed among plasma alpha-carotene, beta-carotene, and lycopene concentrations, and overall risk of prostate cancer diagnosis [odds ratio (highest versus lowest quintile; OR), alpha-carotene: OR, 0.67 [95% confidence interval (CI), -0.40-1.09]; beta-carotene: OR, 0.78 (95% CI, 0.48-1.25); lycopene: OR, 0.66 (95% CI, 0.38-1.13)]. The inverse association between plasma lycopene concentrations and prostate cancer risk was limited to participants who were 65 years or older (OR, 0.47; 95% CI, 0.23-0.98) and without a family history of prostate cancer (OR, 0.48; 95% CI, 0.26-0.89). Combining, older age and a negative family history provided similar results (OR, 0.43; 95% CI, 0.18-1.02). Inverse associations between beta-carotene and prostate cancer risk were also found among younger participants (<65 years of age; OR, 0.36; 95% CI, 0.14-0.91; P(trend) = 0.03). Combining dietary intake and plasma data confirmed our results. We found a statistically significant inverse association between higher plasma lycopene concentrations and lower risk of prostate cancer, which was restricted to older participants and those without a family history of prostate cancer. This observation suggests that tomato products may exhibit more potent protection against sporadic prostate cancer rather than those with a stronger familial or hereditary component. In addition, our findings also suggest that among younger men, diets rich in beta-carotene may also play a protective role in prostate carcinogenesis.     

Additional Diagnostic Yield of Adding Serology to PCR in Diagnosing Viral Acute Respiratory Infections in Kenyan Patients 5 Years of Age and Older

The role of serology in the setting of PCR-based diagnosis of acute respiratory infections (ARIs) is unclear. We found that acute- and convalescent-phase paired-sample serologic testing increased the diagnostic yield of naso/oropharyngeal swabs for influenza virus, respiratory syncytial virus (RSV), human metapneumovirus, adenovirus, and parainfluenza viruses beyond PCR by 0.4% to 10.7%. Although still limited for clinical use, serology, along with PCR, can maximize etiologic diagnosis in epidemiologic studies.     

Direct sequencing of SARS-coronavirus S and N genes from clinical specimens shows limited variation

Severe acute respiratory syndrome-associated coronavirus (SARS-CoV) emerged, in November 2002, as a novel agent causing severe respiratory illness. To study sequence variation in the SARS-CoV genome, we determined the nucleic acid sequence of the S and N genes directly from clinical specimens from 10 patients--1 specimen with no matched SARS-CoV isolate, from 2 patients; multiple specimens from 3 patients; and matched clinical-specimen/cell-culture-isolate pairs from 6 patients. We identified 3 nucleotide substitutions that were most likely due to natural variation and 2 substitutions that arose after cell-culture passage of the virus. These data demonstrate the overall stability of the S and N genes of SARS-CoV over 3 months during which a minimum of 4 generations for transmission events occurred. These findings are a part of the expanding investigation of the evolution of how this virus adapts to a new host.