类似胆总管囊肿的胆总管横纹肌肉瘤：阻塞性黄疸的罕见原因

肝外胆道肿瘤罕见,其中以横纹肌肉瘤最常见。横纹肌肉瘤是一种软组织恶性肌肉骨骼肿瘤,是儿童非常罕见的一种胆总管恶性肿瘤。它通常表现为阻塞性黄疸和/或瘙痒。如果肿瘤没有局部浸润邻近组织,其影像学表现则类似胆总管囊肿。因此,确诊通常是在手术时或术前通过活检。早期诊断、与胆总管囊肿鉴别、尽早开始治疗对延长患者生存时间有重要意义。该文报道1例10岁男童,反复阻塞性黄疸和发热,术前诊断为胆总管囊肿,术后确诊为胆总管胚胎性横纹肌肉瘤。经手术切除、术后化疗,该患儿预后良好。故必须了解这种罕见的肿瘤可以类似先天性胆总管囊肿,并且在儿童阻塞性黄疸的鉴别诊断时应加以考虑。     

Neurological complications following Plasmodium falciparum infection

Several neurological complications are associated with severe falciparum malaria. Cerebral malaria is one of the most life-threatening complications. A few patients may experience a neurological syndrome after complete recovery from Plasmodium falciparum infection. In the literature especially the postmalaria neurological syndrome (PMNS), acute disseminated encephalomyelitis (ADEM) and delayed cerebellar ataxia have been reported. We describe a case of a 53-year-old woman who was readmitted after an adequately treated P. falciparum infection with word-finding difficulties, confusion and tremor. Peripheral blood smears were repeatedly negative for malarial parasites. The clinical features best fitted a PMNS. Because of the severity of the syndrome she was treated with high-dose prednisone. She recovered completely. The possibility of ADEM is also discussed. Aetiology of these syndromes is still unknown, but it could be mediated by an immunological mechanism. PMNS or ADEM must be considered when neurological signs and symptoms occur after recovery from a P. falciparum infection.     

Expression of distinct α1-adrenoceptor phenotypes in the iris of pigmented and albino rabbits

Background and purpose:

The expression of multiple pharmacological phenotypes including α_1L-adrenoceptor has recently been reported for α₁-adrenoceptors. The purpose of the present study was to identify α₁-adrenoceptor phenotypes in the irises of pigmented and albino rabbits.

Experimental approach:

Radioligand binding and functional bioassay experiments were performed in segments or strips of iris of pigmented and albino rabbits, and their pharmacological profiles were compared.

Key results:

[³H]-silodosin at subnanomolar concentrations bound to intact segments of iris of pigmented and albino rabbits at similar densities (approximately 240 fmol·mg⁻¹ protein). The binding sites in the iris of a pigmented rabbit were composed of a single component showing extremely low affinities for prazosin, hydrochloride [N-[2-(2-cyclopropylmethoxyphenoxy)ethyl]-5-chloro-α,α-dimethyl-1H-indole-3-ethamine hydrochloride (RS-17053)] and 5-methylurapidil, while two components with high and low affinities for prazosin, RS-17053 and 5-methylurapidil were identified in irises from albino rabbits. In contrast, specific binding sites for [³H]-prazosin were not clearly detected because a high proportion of non-specific binding and/or low affinity for prazosin occurred. Contractile responses of iris dilator muscle to noradrenaline were antagonized by the above ligands, and their antagonist affinities were consistent with the binding estimates at low-affinity sites identified in both strains of rabbits.

Conclusions and implications:

A typical α_1L phenotype with extremely low affinity for prazosin is exclusively expressed in the iris of pigmented rabbits, while two distinct phenotypes (α_1A and α_1L) with high and moderate affinities for prazosin are co-expressed in the iris of albino rabbits. This suggests that a significant difference in the expression of phenotypes of the α₁-adrenoceptor occurs in the irises between the two strains of rabbits.     

Clostridium cadaveris bacteraemia: two cases and review

Clostridium cadaveris is a strict anaerobic Gram-positive rod that is the most prominent bacterium during the decay of dead bodies. We present 2 rare cases of bacteraemia with C. cadaveris. The source of both infectious episodes was most probably of gastrointestinal origin.     

Intracerebral tuberculomas in a pregnant Somalian woman

A pregnant Somalian woman aged 28 years, in the Netherlands for the last five years, suffered from a progressive hemiparesis, epilepsia, behavioural problems and low fever. Brain MRI showed multiple lesions with contrast enhancement. Extensive serologic and parasitologic tests on serum and cerebrospinal fluid did not disclose any cause. A brain biopsy revealed only necrosis, but bacterial culture and polymerase chain reaction (PCR) supplied the diagnosis of 'tuberculosis'. PCR on the cerebrospinal fluid remained negative. In the meantime the chest X-ray showed miliary tuberculosis and a spine MRI thoracic spondylodiscitis and a large paravertebral abscess. Subsequently the patient was treated successfully with tuberculostatic agents. Her healthy child which was born by caesarean section was treated with the tuberculostatic agents as well.     

Pathophysiology of in-vitro induced filaments, spheroplasts and rod-shaped bacteria in neutropenic mice

This study compared the in-vitro properties and in-vivo effects of Escherichia coli filaments, spheroplasts and normal cells in a murine thigh infection model. E. coli was exposed to ceftazidime, meropenem or saline to obtain filaments, spheroplasts or normal bacilli, which were then injected into neutropenic mice. After 24 h, morphology, CFUs, local and circulating endotoxin levels, cytokine levels and mortality were recorded, and correlations between bacterial and host parameters of infection were investigated. Filaments and spheroplasts contained more endotoxin/CFU than controls. Histological studies showed that morphologically altered bacteria changed into rod-shaped cells in the absence of antibiotics. Bacterial spread to the liver was significantly higher in mice challenged with rod-shaped cells, compared with antibiotic-exposed bacteria (p 0.007). Muscle endotoxin levels correlated significantly with circulating interleukin (IL)-6 and tumour necrosis factor (TNF)-alpha, and both pro-inflammatory cytokines were correlated significantly (p 0.011). Despite a tendency toward higher local and systemic concentrations of endotoxin in the filament group, inflammatory responses and survival did not differ between groups. It was concluded that morphologically altered bacteria contain more endotoxin and can regain a rod shape after withdrawal of antibiotics, while non-antibiotic-exposed bacteria show greater spread to the liver. There was a clear intra-individual relationship between local endotoxin, systemic endotoxin, TNF-alpha and IL-6 production, but these parameters did not differ among groups.     

Concentration-dependency of β-lactam-induced filament formation in Gram-negative bacteria

Ceftazidime and cefotaxime are β-lactam antibiotics with dose-related affinities for penicillin-binding protein (PBP)-3 and PBP-1. At low concentrations, these antibiotics inhibit PBP-3, leading to filament formation. Filaments are long strands of non-dividing bacteria that contain enhanced quantities of endotoxin molecules. Higher concentrations of ceftazidime or cefotaxime cause inhibition of PBP-1, resulting in rapid bacterial lysis, which is associated with low endotoxin release. In the present study, 37 isolates of Escherichia coli , Klebsiella spp . , Pseudomonas aeruginosa and Acinetobacter spp . were studied over a 4-h incubation period in the presence of eight concentrations of ceftazidime or cefotaxime. As resistance of Gram-negative bacteria is an emerging problem in clinical practice, 14 isolates of E. coli and Klebsiella pneumoniae that produced extended-spectrum β-lactamases (ESBLs) were also investigated. Morphological changes after exposure to the β-lactam antibiotics revealed recognisable patterns in various bacterial families, genera and isolates. In general, all isolates of Enterobacteriaceae produced filaments within a relatively small concentration range, with similar patterns for E. coli and K. pneumoniae . Pseudomonas and Acinetobacter spp. produced filaments in the presence of clinically-relevant concentrations of both antibiotics as high as 50 mg/L. In all genera, filament-producing capacity was clearly related to the MIC. Ceftazidime induced filament production in more isolates and over wider concentration ranges than did cefotaxime. Interestingly, ESBL-producing isolates were not protected against filament induction. The induction of filament production may lead to additional risks during empirical treatment of severe infections.