High-fat diet negatively affects brain markers, cognitive behaviors, and noncognitive behaviors in the rTg4510 tau mouse model

Alzheimer's disease (AD) drastically impacts cognitive and noncognitive behaviors in both humans and animal models. Two hallmark proteins in AD, amyloid-β plaques and tau neurofibrillary tangles, accumulate in regions of the brain critical for learning and memory, including the hippocampus. Poor dietary choices have been shown to exacerbate cognitive deficits seen in AD. In this study, we assessed the effects of a high-fat diet (HFD - 60 kcal% fat) on cognitive & noncognitive behaviors as well as on brain markers in the rTg4510 tau mouse model. While all mice learned the Morris Water Maze (MWM) task, it was noted that on the last day of acquisition female tau mice had a significantly higher latency to find the platform than male tau mice (p < 0.01). Mice given the HFD spent significantly less time in the target quadrant than those given a control diet (CD) (p < 0.05). Tau mice showed impaired burrowing (p < 0.05) and nesting behaviors (p < 0.001) compared to WT mice and HFD administration worsened burrowing in tau mice. Tau mice exhibited greater levels of glial fibrillary acidic protein (GFAP) (p < 0.05) and significantly less hippocampal cell density than WT mice (p < 0.001). We observed trends of HFD mice having greater levels of GFAP and greater average tangle size than CD mice. These results highlight the importance of dietary choices, especially in older populations more susceptible to AD and its effects.

Smoking in Colombian medical schools: the hidden curriculum

BACKGROUND

Tobacco companies are focusing their interest in less developed countries. In the absence of governmental opposition, physicians are expected to lead tobacco control efforts. We studied Colombian medical students' smoking prevalence and tobacco attitudes.

METHODS

First- and fifth-year students from 11 medical schools in seven Colombian cities answered anonymous, self-administered, 38-item questionnaires. Additionally, smokers answered the Fagerström Test for Nicotine Dependence (FTND).

RESULTS

Two thousand twenty-one students (males 50.6%; age 15-44, median 19) completed the survey; average response rate was 89.9%. Globally 25.9% of students were current smokers (males 27.9%, females 24.0%). Living at higher altitude and attending private universities were associated with higher prevalence (P < 0.001). Males had a higher chance of having given up smoking (P < 0.05); 91.3% of current smokers would like to quit; 67.3% of all smokers and 44.8% of daily smokers scored 0 in the FTND. Prevalence was similar among first- and fifth-years, but fifth-year students were more complacent with smoking in health centers and showed a lesser desire to quit.

CONCLUSIONS

Medical students' smoking prevalence is similar to that of the general population. Tobacco control strategies need to be included in the curriculum. Nicotine addiction does not seem to be the main perpetuating factor.

APOE epsilon4 and Alzheimer's disease: positive association in a Colombian clinical series and review of the Latin-American studies

OBJECTIVE

As the strength of the association between the APOE epsilon4 allele and Alzheimer's disease (AD) varies across ethnic groups, we studied if there was such an association in Colombian patients.

METHOD

We performed apolipoprotein E (APOE) genotyping in a clinical sample of 83 unrelated AD patients, predominantly late-onset (>65 yrs) including familial ( n =30) and sporadic AD cases (n= 53) diagnosed according to NINCDS-ADRDA criteria and assessed by a multi-disciplinary team. Control subjects (n = 44) had no significant cognitive impairment by medical interview and neuro-psychological testing.

RESULTS

We found a high association (OR= 5.1 95%CI 1.9 -13.6) between APOE epsilon4 and AD, in this series with predominantly late-onset cases with familial aggregation in 24 cases (28.9%). A significant negative association was found between epsilon2 and AD (OR= 0.2 95% CI 0.05-0.75).

CONCLUSION

Further population-based surveys in Colombia are warranted to precise a possible dose effect of APOE epsilon4.

Prescription patterns of recently graduated physicians in Colombia: a survey during the mandatory social work period

MAIN OBJECTIVE

To quantify prescribing patterns of physicians during their year of social work in health centers of Bogotá, Colombia, for three tracer conditions: acute respiratory infection (ARI), systemic hypertension (SH) and acute diarrhea (AD).

DESIGN

Cross-sectional survey.

SETTING

Primary Care Health Centers in the city of Bogotá.

STRATEGY

The Health District Department of Bogotá (Secretaria Distrital de Salud) provided the sampling frame of SILOS (Local Health System) and UPAS (primary health service units) with a physician in the social work year. Samples of patient-physician encounters for the three tracer conditions within UPAS were examined, and detailed information collected on prescription indicators.

RESULTS

Information was collected on a total of 1099 patient-physician encounters. Results show that 61% (95% CI: 58.6-63.1) of prescriptions in these settings are non-generic, and only 62% (95% CI: 59.5-64.0) are from the Colombian essential drug list. Number of medications prescribed per encounter were higher with ARI, as well as prescriptions for non-generic forms, antibiotics, and medications outside of the Colombian essential drug list. Inappropriate prescriptions were seen in 31% (95% CI: 28.1-33.7) of all encounters.

DISCUSSION

Inadequacy of prescriptions (based on diagnosis) suggest that the teaching of rational prescribing patterns should be targeted with much more emphasis in schools of medicine. Interventions focused on the outstanding deficiencies should be designed and properly evaluated.

Ventilatory mechanics in healthy calves during helium-oxygen breathing

The mechanics of breathing was investigated in six healthy calves breathing either air or a mixture of 79% helium and 21% oxygen (He-O2). Intrapleural pressure (Ppl) was measured with an esophageal balloon catheter and transpulmonary pressure was obtained by subtracting the mouth pressure (Pm) from Ppl. Respiratory airflow (V) was measured using a Fleisch pneumotachograph N degrees 3 and tidal volume (Vt) was electronically derived by integrating V with respect to time. Respiratory airflow, Vt, Ppl and Pm were simultaneously recorded while the calves breathed first air (1 min), secondly He-O2 (1 min) and finally air again (1 min). The pulmonary function values were calculated on the tracings and the He-O2 values were compared to the corresponding "air" values. The ventilatory response to resistance unloading was characterized by a significant increase in minute volume exclusively due to an increase in respiratory frequency, while Vt remained unchanged. A decrease of 32% in the total pulmonary resistance (RL) and 16% in the work per litre of ventilation (Wrm/l) were observed when calves breathed He-O2. The effect of the He-O2 on RL and on Wrm/l suggests that, in the bovine species, airflow turbulances in the upper part of the respiratory tract play a significant role in the total airways resistance.

Decrease in number of somatostatin receptors in rat brain after adrenalectomy: normalization after glucocorticoid replacement

The effects of adrenalectomy on somatostatin (SS) concentration and specific binding in cerebral cortex, hippocampus, striatum, and hypothalamus were examined using [125I-Tyr11]SS as the binding ligand. Adrenalectomy did not affect the concentration of SS-like immunoreactivity in the brain areas studied. Nevertheless, the number of SS receptors was significantly decreased in membrane preparations from hippocampus, striatum, and hypothalamus, but not in cerebral cortex. No significant differences in the apparent binding affinity values were seen after adrenalectomy. The adrenalectomy-induced decreases in [125I-Tyr11]SS receptors were completely reversed by glucocorticoid replacement with dexamethasone. These results demonstrate that adrenalectomy modulates SS receptors in discrete brain areas, suggesting the existence of a possible relationship between corticosteroids and SS in the neuronal activity of these structures. The physiological significance of these findings remains to be clarified.