Stereological analysis of hippocampus in rat treated with chemotherapeutic agent oxaliplatin

BACKGROUND

Oxaliplatin (OX) has been widely used for treatment of colorectal and other cancers. Adverse effect of OX and other anticancer agents on cognition have been reported, but studies on the effects of chemotherapy on brain structure are scarce. This study describes the morphometrical features of the hippocampus structures in rat following OX treatment using design-based stereological methods.

MATERIALS AND METHODS

Ten male Wistar rats were randomised into two groups. The rats from OX group received 2.4 mg/kg OX in vehicle for 5 consecutive days every week for 2 weeks intraperitoneally. Controls received vehicle only. Cavalieri's method and the optical fractionator method were used for volume and neuron estimation, respectively.

RESULTS

Cavalieri's method was used to estimate volume and showed that the volume of the hippocampus was significantly decreased in OX group (31.84 ± ± 1.24 mm3) compared with the vehicle control group (36.95 ± 3.48 mm3). The optical fractionator method was used to estimate neuron number and showed that the number of neurons in dentate gyrus, cornu ammonis 1 and 3 in OX group (8.147 ± 2.84 × 105, 4.257 ± 0.59 × 105 and 2.133 ± 0.22 × 105, respectively) did not differ from those of vehicle control group (7.36 ± 1.42 × 105, 3.521 ± ± 0.54 × 105 and 1.989 ± 0.46 × 105, respectively).

CONCLUSIONS

These findings suggested that OX treatment induces loss of hippocampal volume without neuronal loss which might help to clarify the mechanism by which OX affects cognition and to improve preventive treatment strategies.

Fluoxetine effects on molecular, cellular and behavioral endophenotypes of depression are driven by the living environment

Selective serotonin reuptake inhibitors (SSRIs) represent the most common treatment for major depression. However, their efficacy is variable and incomplete. In order to elucidate the cause of such incomplete efficacy, we explored the hypothesis positing that SSRIs may not affect mood per se but, by enhancing neural plasticity, render the individual more susceptible to the influence of the environment. Consequently, SSRI administration in a favorable environment promotes a reduction of symptoms, whereas in a stressful environment leads to a worse prognosis. To test such hypothesis, we exposed C57BL/6 mice to chronic stress in order to induce a depression-like phenotype and, subsequently, to fluoxetine treatment (21 days), while being exposed to either an enriched or a stressful condition. We measured the most commonly investigated molecular, cellular and behavioral endophenotypes of depression and SSRI outcome, including depression-like behavior, neurogenesis, brain-derived neurotrophic factor levels, hypothalamic-pituitary-adrenal axis activity and long-term potentiation. Results showed that, in line with our hypothesis, the endophenotypes investigated were affected by the treatment according to the quality of the living environment. In particular, mice treated with fluoxetine in an enriched condition overall improved their depression-like phenotype compared with controls, whereas those treated in a stressful condition showed a distinct worsening. Our findings suggest that the effects of SSRI on the depression- like phenotype is not determined by the drug per se but is induced by the drug and driven by the environment. These findings may be helpful to explain variable effects of SSRI found in clinical practice and to device strategies aimed at enhancing their efficacy by means of controlling environmental conditions.

No evidence for loss of hippocampal neurons in non-Alzheimer dementia patients

OBJECTIVE

To use stereological methods for estimating the total number of neurons in hippocampi of non-Alzheimer demented patients.

MATERIAL AND METHODS

Hippocampi from six women with severely impaired memory but without Alzheimer pathology were compared with six mentally intact age-matched female controls. The total number of neurons was estimated in the granule cell layer of the dentate gyrus, the hilus of the dentate gyrus, the pyramidal cell layer of CA3 and CA2, the pyramidal cell layer of CA1 and the cellular layer of subiculum using the optical fractionator.

RESULTS

The total neuron number was the same in the dementia cases, 22.4 x 106, compared with 22.7 x 106 in the controls (P = 0.85). No region-specific group differences or side difference were found. Two cases without clinical signs of dementia but with abundant plaques and tangles in hippocampus and neocortex had total neuron numbers within normal limits.

CONCLUSION

Our results indicate that severely impaired memory can occur in the presence of intact numbers of hippocampal neurons in non-Alzheimer dementia and that nerve cell loss in the hippocampus might be characteristic for Alzheimer's disease, and perhaps other forms of primary cortical dementia.

[Analysis of the activity of neurologic intensive care units]

The authors analysed six-year activity of the intensive Care Unit of Department of Neurology, Medical University of Pécs (POTEI), and two-year activity of the Intensive Care Unit of Department of Neurology, Semmelweis University of Medicine, Budapest (SOTEI). Mortality at POTEI and SOTEI was 33.9% and 32.2%, respectively. Mean duration of stay of survivors at POTEI was 10 +/- 12.8 days, and 7 +/- 6.8 days at SOTEI; mean duration of care of the deceased patients at POTEI was 6.3 +/- 10.5 days, and 10 +/- 13.7 days at SOTEI. At POTEI 60.7%, at SOTEI 63% of the patients was admitted because of cerebrovascular insult. Mortality of patients with brain haemorrhage at POTEI and SOTEI was 53.4% and 57.7% respectively. Mortality of the ischaemic group was 40.6% (POTEI) and 35.3% (SOTEI). In the group of intracranial tumours 44.4% mortality was recorded at POTEI and 47.6% at SOTEI. At POTEI 240 patients (15.9%), while at SOTEI 94 patients (21%) were admitted to treat epileptic seizures. Among the 510 patients, who died within one month 284 patients (55.6%) were unconscious at admission. From those with coma due to severe structural lesion of the brain (brain ischaemia, bleeding, meningitis) only 15 patients survived. Among the 184 patients, who were comatose and survived, the most frequent diagnosis was suicidal attempt with hypnotics (n = 67), metabolic encephalopathy (n = 19) and epilepsy (n = 12). At SOTEI among the 144 deceased patients 102 (70.8%) were unconscious at admission. Coma at admission proved to be a strong predictor of mortality. Mortality of the ventilated patients was 83% at POTEI and of those having subclavian catheter (n = 592) was 47.1%. In the acute phase of brain ischaemia at POTEI 39%, at SOTEI 10.7% of the patients received heparin. At SOTEI the cost of medication of patients who died after two weeks of care was 65.2% higher than that of the survived patients.