Olfactory function in patients with hyposmia compared to healthy subjects - An fMRI study

BACKGROUND

Individuals with hyposmia, or the partial loss of smell, represent a large sector (15 %) of the population that is likely to grow with the current aging population; however, our understanding to how hyposmics centrally process odors is still not clear. One popular non-invasive tool for in vivo imaging of biological activity among human brains has been function magnetic resonance imaging (fMRI) which uses blood-oxygenation level dependent (BOLD) signal as an indirect measurement. Therefore, the aim of this study was to understand differences in olfaction processing between patients with hyposmia and healthy controls using functional magnetic resonance imaging (fMRI).

METHODOLOGY

Eleven hyposmic and 12 healthy, normosmic subjects were exposed to two different food-related odors (coffee and peach) during a block-designed fMRI session. Additionally, odor perception qualities were rated for each odor throughout the scanning session.

RESULTS

The activations of the normosmic group were localized in typical olfactory areas (insula, orbitofrontal cortex [OFC], limbic system and amygdala). The hyposmic group showed similar regions of activation (insula, OFC, limbic system), however, less activation was found in the amygdala, left anterior cingulate and right OFC, but higher activation was shown in the right parahippocampal and both the left and right posterior cingulate gyrus which are assumed to play an important role in the processing and remembrance of memories.

CONCLUSIONS

These results indicate similar central olfactory processing among groups, yet subjects with partial loss may attempt to compensate smell impairment with odor memory or higher motivation to smell.

[Isolated congenital anosmia--clinical and daily life aspects of a life without a sense of smell]

BACKGROUND

Isolated congenital anosmia is a disorder (ICA) characterized by not or only rudimentary developed central olfactory structures. This results in the lack of the sense of smell since birth. Although this phenomenon is known among clinicians almost no knowledge exists on how those people cope with the disorder.

MATERIAL AND METHODS

43 people with ICA were asked with a standardised questionnaire about when they fi rst noticed their disorder, how they experience the lack of smelling ability and about different aspects of daily life.

RESULTS

ICA is detected by the patients self or by their parents at the age of 10 in average. However about 13 years pass, until the right diagnosis is confirmed. In contrast to people with acquired olfactory loos ICA patients have developed strategies to adapt to the deficit in daily life. Nevertheless they report increased social insecurity and more hazardous events.

CONCLUSION

The results can be of advantage for clinicians and patients to get a better understanding of the disorder.

Two patients with horseshoe kidney and ruptured abdominal aortic aneurysm

Renal anomalies present a challenge to surgeons who repair aortic aneurysms; horseshoe kidneys occur in 1 out of 400 people in the general population. The degree of fusion, accessory blood supply and ureteric anomalies all affect the approach to aneurysm repair in the elective or emergency setting. The authors report two patients with ruptured abdominal aortic aneurysms, who were found at operation to have a horseshoe kidney. In both cases a thick renal isthmus was found crossing the aorta between the inferior mesenteric artery and the bifurcation. The kidney was preserved intact, accessory blood supply was controlled from inside the aorta and the aneurysm was repaired with a Dacron graft. One patient underwent ureterolysis; although renal failure subsequently developed, it was likely related to prolonged preoperative hypotension. The other patient recovered without complications.

Peripheral nerve injection injury with purified bovine collagen--an experimental model in the rat

This study investigated the effect of purified bovine collagen (Zyderm collagen implant) on peripheral nerve tissue in rats. Zyderm was injected extrafascicularly and intrafascicularly into the sciatic nerve of adult Wistar rats. The nerves were examined by light and electron microscopy and the integrity of the blood-nerve barrier assessed by protein tracer technique. With light microscopy the precise anatomical location of the injected material could be identified. The purified bovine collagen did not appear to be neurotoxic. After extrafascicular injection, only minimal nerve fiber damage was seen. Intrafascicular injection produced a histological picture compatible with compression neuropathy and was associated with a breakdown in the blood-nerve barrier.