兔眼内铁磁性异物MRI诊断研究

为探讨眼内铁磁性异物ＭＲＩ时的移动性，对９枚铁屑（０．２ｍｍ×０．２ｍｍ×０．１ｍｍ～４ｍｍ×３ｍｍ×３ｍｍ）进行了体外实验，对１０枚铁屑（０．２ｍｍ×０．１ｍｍ×０．１ｍｍ～３．５ｍｍ×３ｍｍ×３ｍｍ）进行了体内实验。体外实验将铁屑放入盛有兔眼玻璃体的透明玻璃瓶中，体内实验将异物置入５只兔的１０眼玻璃体内。ＭＲＩ使用ＳｉｅｍｅｎｓＩｍｐａｃｔ１．０ＴＭＲ机。体内实验ＭＲＩ前后经检眼镜和ＣＴ观察异物移动情况，并拍摄Ｘ线平片。结果：体外实验发现仅１枚最小铁屑（０．２ｍｍ×０．２ｍｍ×０．１ｍｍ）未见移动，其他８枚均见异物向主磁场方向移动。体内实验３枚小于０．３ｍｍ×０．３ｍｍ×０．２ｍｍ铁屑未见移动，大于０．４ｍｍ×０．３ｍｍ×０．２ｍｍ的７枚铁屑均见移动，但并未导致视网膜损伤。ＭＲＩ均发现铁异物周围有大于异物数十倍的金属伪迹；小于０．４ｍｍ×０．３ｍｍ×０．２ｍｍ的４枚铁屑Ｘ线平片均未显示。结果提示：眼内铁磁性异物移动性与异物大小有关，异物愈大愈易移动；Ｘ线平片不能显示的眼内铁异物在１．０ＴＭＲ机下行ＭＲＩ是安全的     

Amyloid β protein (Aβ) deposition in dementia with Lewy bodies: predominance of Aβ42(43) and paucity of Aβ40 compared with sporadic Alzheimer's disease

Amyloid β protein (Aβ) deposition was investigated by quantitative immunohistochemistry in 13 cases of dementia with Lewy bodies (DLB) and compared with that in a series of age, gender and ApoE genotype matched cases of Alzheimer's disease (AD). In DLB the predominant Aβ peptide species deposited was Aβ₄₂₍₄₃₎ and this was similar in amount to that in AD. By contrast, Aβ₄₀ deposition was sparse in DLB and was lower than that in AD as was the total Aβ (Aβ₄₀+Aβ₄₂₍₄₃₎ ) deposition. These data reinforce the viewpoint that in all disorders in which Aβ deposition is characteristic, the initial and predominant peptide species deposited is the longer form, Aβ₄₂₍₄₃₎ . The density of Lewy bodies (LB) in DLB was unrelated to the extent of Aβ deposition, although those cases possessing one or more copies of the apolipoprotein E E4 allele had a higher LB density than those without an E4 allele. This suggests that the apolipoprotein E E4 isoform might facilitate, though not necessarily trigger, the formation of LB in susceptible individuals.     

Polyneuropathy in hypothyroidism

Summary Clinical and sural nerve biopsy findings are described in four hypothyroid patients with manifestations of a diffuse peripheral neuropathy. Clinical examination revealed distal sensory inpairment, complaints of burning and lancinating extremity pains, ataxia and a decrease of deep tendon reflexes with total ankle jerk loss. In one patient, signs of the peripheral neuropathy comprised the leading symptomatology of the underlying metabolic disorder. Light and electron microscopic investigations of the sural nerve biopsies revealed a marked reduction of myelinated fibers, affecting mainly the large myelinated axons. The histograms showed a pathological unimodal spectrum of myelinated fiber diameters. Dystrophic and degenerative changes in axons of all fiber classes and the presence of clusters of thinly myelinated small fibers suggest that neuroaxonal degeneration and incomplete regeneration may represent the major pathogenetic mechanism of the neuropathy in these hypothyroid patients. Neuropathological studies on myxoedematous neuropathy are as scarce and insufficient as studies on myxoedematous myopathy are abundant and detailed. G. W. Bruyn and H. Garland, 1970     

Juvenile Form der subakuten nekrotisierenden Encephalomyelopathie (Leigh) mit ungewöhnlicher ZNS-Lokalisation

Summary The case of an adolescent girl aged 16 with subacute necrotizing encephalomyelopathy (Leigh) is reported. The chronic course of illness lasting for 7.5 years was characterized by visual and gait disorders progressing to blindness, incomplete spastic tetraparesis, and fatal respiratory insufficiency. Neuropathology, in addition to CNS lesions with typical pattern, revealed involvement of Ammon's horn, fornix, corpora mammillaria, tractus mammillothalamicus, and corpus callosum. The massive damage to the total Ammon's horn formation, the distribution of which correlates to none of the established patterns of lesion, is related to the primary disease given, and an additional secondary transneuronal degeneration of associated systems is suggested.

     

Biological monitoring of occupational exposure to methyl ethyl ketone by means of urinalysis for methyl ethyl ketone itself

Summary Head space gas chromatography (GC) was applied to measure methyl ethyl ketone (MEK) in urine from 62 MEK-exposed male workers, whose individual intensity of exposure to MEK was monitored utilizing the carbon felt dosimeter. The urinary MEK level increased rapidly to reach a plateau in the first quarter of the daily 8-h work, while very little MEK was detected in the preshift urine. When the MEK levels in the urine at the end of the shift were compared with the afternoon MEK-TWA values, the uncorrected MEK in urine correlated best with MEK in air (r=0.774, n=62), while correction for creatinine gave a comparable result and the correlation was poorer when corrected for a specific gravity of urine or for the lapse of time after preceding passage of urine. Balance of MEK absorption via inhalation and MEK excretion into urine revealed that only 0.1% of MEK absorbed will be excreted unchanged into urine. Wider application of head space GC is discussed for the analysis of unmetabolized solvents in urine.     

Studies on primary cultures of adult lens cells from normal and hereditary cataractous mice.

Lens epithelial cells from normal and congenital cataractous mice strains were cultured under similar conditions. Both normal and cataractous cells actively propagated and reached confluency on the eleventh day. These cells, thereafter, underwent morphological changes characterized by cell elongation, aggregation and formation of lentoid bodies at about 15 days.Electron microscopy revealed these lentoid bodies to consist of immature lens cells. These structures derived from cataractous cells had numerous vacuoles in the cytoplasm much more so than in the normal lens cells. In addition, some lentoid bodies closely resembled mature fibers of the intact lens. It was also demonstrated that these lentoid bodies showed positive immunofluorescence when reacted with fluorescent antiserum to γ-crystallin.There were certain differences observed between the cultured cells derived from normal lens and Nakano cataract. The disappearance of organelles and denucleation process were delayed in the lentoid bodies found in cultured Nakano cells when compared to normal cell culture. In addition a second type of lentoid body, although present as a minor population, was observed in the Nakano cell culture. Other subtle differences were observed during the course of culturing normal and cataractous lens cells.     

Cytokeratin CK 7 and CK 20 expression in pituitary adenomas

The pattern of immunohistochemical expression of cytokeratins 7 (CK 7) and 20 (CK 20) is commonly used to assess possible primary sites of metastatic carcinomas. Because pituitary tumors are almost always benign, there has been little interest in their cytokeratin profile. However, we recently reported the use of CK 7/20 expression to document malignant progression and metastasis of a pituitary tumor, indicating the potential diagnostic usefulness of the CK 7/20 profile of pituitary adenomas. We analyzed CK 7/20 expression in 97 pituitary adenomas subclassified by immunohistochemical hormone expression. In about 90% of all subtypes, CK 7 was either negative or reactive in only a few scattered cells. Corticotrophs and sparsely granulated growth hormone-positive adenomas were consistently CK 20 positive (and CK 7 negative) whereas all other subtypes were almost always CK 20 negative. This CK 20-positive, CK 7-negative profile is previously described consistently only in colonic adenocarcinomas. This study documents that subtypes of pituitary adenomas have different CK 7/20 profiles. Whereas this pattern is likely to have diagnostic usefulness in only rare adenomas, the presence of a unique CK signature in corticotrophs and sparsely granulated growth hormone-positive adenomas, subtypes particularly noted for invasive and aggressive behavior, merits further investigation.     

Partial unilateral lesions of the mushroom bodies affect olfactory learning in honeybees Apis mellifera L

The mushroom bodies (MBs) are central structures in the insect brain that have been associated with olfactory learning and memory. Here we used hydroxyurea (HU) to treat honeybee larvae and induce partial MB ablations at the adult stage. We studied olfactory learning in honeybees with unilateral loss of the median calyces of their MBs and compared their ability to solve different forms of olfactory discrimination. When odorants were delivered in a side-specific manner, ablated bees could not solve either discrimination of the unambiguous problem (Paradigm 1: A+, B- on one antenna, C+, D- on the other; A+B-/C+D-) whereas they could solve at least one of both discriminations of the ambiguous problem (Paradigm 2: A+B-/A-B+), namely that proposed to their intact brain side. Non-ablated bees could learn side-specific discriminations on both brain sides. When odorants were delivered simultaneously to both antennae (Paradigm 3: A+B-C+D-), HU-ablated bees learned slower than HU-normal bees. Thus, in all three paradigms, the unilateral loss of a median calyx affected olfactory learning. We propose that the MBs are required for solving elemental olfactory tasks whose complexity is increased by the number of stimuli involved and that MB ablations could have an effect on the inhibition of information exchange between brain hemispheres.     

The absent and vanishing spleen: congenital asplenia and hyposplenism--two case reports

Two unrelated patients are reported: one with isolated familial asplenia diagnosed postmortem, the other with isolated hyposplenism diagnosed after recurring invasive bacterial infections. Because both children died of fulminant septic shock, the importance of early diagnosis of splenic dysfunction is evident. Clues for an early diagnosis of congenital asplenia are recurrent invasive bacterial infections, Howell-Jolly bodies in the blood smear or a relative with congenital isolated asplenia. Although the guidelines for infection prevention in asplenism--patient education, antibiotic prophylaxis and vaccination--are well defined, controversy remains as to how to differentiate hyposplenism from functional asplenism. Conclusion: Based on the present observations, we define a patient as functionally asplenic--and therefore at risk for life-threatening infections-when Howell-Jolly bodies are present in the blood smear, a very small spleen is found by ultrasound, or splenic blood flow is compromised.     

Follow-up investigations in cerebrospinal fluid of patients with dementia with Lewy bodies and Alzheimer’s disease

Summary. Measuring proteins in cerebrospinal fluid (CSF) has gained wide acceptance for the differential diagnosis of dementia. Some groups have already extended these investigations in Alzheimers disease (AD) by asking how stable these markers are in follow-up analysis, if they depend on the stage of disease and whether they can be used to monitor the progression and biological effects of treatment. We evaluated 21 patients with dementia with Lewy bodies (DLB) and 19 patients with AD, on two occasions, with regard to levels of tau protein, tau protein phosphorylated at threonine 181 (p-tau), A42, A40 and S-100B protein, using a set of commercially available assays.Tau protein levels were lower in DLB in first and second LP compared to AD and decreased during course of both groups. P-tau levels were increased in AD and DLB and decreased during follow-up. A42 and A40 remained relatively stable during follow-up but we found a slight increase of the median A42 level in DLB, whereas in AD, A42 tends to decrease during follow-up. S-100B protein increased during follow-up in both diseases.The protein dynamics in DLB and AD are relatively similar. S-100B protein may be a useful marker for follow-up in neurodegenerative diseases but has to be analysed in longer follow-up periods. Tau protein may be used to differentiate between DLB and AD.Follow-up CSF analyses are of limited value for the differentiation of AD and DLB. We conclude that more specific markers have to be established for the differentiation and follow-up of these diseases.