Trigeminal afferent input alters the excitability of facial motoneurons in hemifacial spasm.

OBJECTIVE: To investigate whether skin or muscle afferent input via the trigeminal nerve alters the excitability of facial motoneurons in hemifacial spasm (HFS). METHODS: Botulinum toxin type A (BTX) was injected only to the orbicularis oculi (O. oculi) muscle of 21 patients with idiopathic HFS, and the excitability of the orbicularis oris (O. oris) motoneurons was monitored. The synkinetic response (SR) of the blink reflex and abnormal muscle response (AMR) were recorded from the O. oris before and after treatment. RESULTS: BTX injections produced marked to moderate improvement in the O. oculi of all 21 patients and in the O. oris of 17 (81%). The rectified areas of SR1 and SR2 were smaller after treatment. In particular, the AMR area showed a reduction (p = 0.02). CONCLUSIONS: The significant lessening of spasms in the O. oris after BTX injection to the O. oculi and the concomitant reduction in excitability of O. oris neurons are consistent with the hypothesis that in HFS, skin or muscle afferent volleys via the trigeminal nerve enhance the excitability of facial nerve motoneurons.

Properties of human skin mechanoreceptors in peripheral neuropathy.

OBJECTIVES: To investigate the properties of mechanoreceptors in patients with peripheral neuropathy. The skin mechanoreceptor is a terminal organ of the primary sensory neuron, which is likely to be affected earlier and more severely than is the nerve trunk by peripheral neuropathies. METHODS: Single sensory unit responses to air-puff and electric stimulation were recorded using the microneurographic technique in the glabrous skin of the hand. Receptor transduction time was estimated by a latency difference between electric- and air-puff-induced responses. RESULTS: A total of 38 mechanoreceptive units were obtained from 14 normal subjects. All the units responded to air-puff stimuli irrespective of the receptor type, and receptor transduction time was approximately 2 ms. A total of 32 units were recorded from 11 patients with neuropathy of variable causes. Seven (22%) of the 32 neuropathic units did not respond to air-puffs despite their ability to respond to electric stimulation. Compared to normal ones, units from patients with peripheral neuropathy had significantly higher mechanical thresholds, but receptor transduction times did not differ significantly. CONCLUSIONS: Changes in receptor properties in human neuropathy are characterized by increased mechanical threshold without prolongation of receptor transduction time, possibly due to a high threshold for generating receptor potentials.

Mechanisms of early and late recovery in acute motor axonal neuropathy.

Motor unit number estimate (MUNE) of the abductor pollicis brevis (APB) was sequentially performed in seven patients with acute motor axonal neuropathy (AMAN). The MUNE markedly decreased (mean, 11) at the peak of the illness. Clinical recovery of APB strength began during week 4, with an increase in amplitude of distal compound muscle action potentials. The MUNE did not change significantly in this early recovery phase and increased slowly with time. The main mechanism for early recovery in AMAN may be collateral reinnervation, with nerve regeneration developing later.

[Role of neutrophils in acute lung injury induced by Candida sepsis].

To evaluate the role of inflammatory cells in acute lung injury induced by Candida sepsis, we investigated the time course of cell counts in bronchoalveolar lavage (BAL) fluid, the lung wet-to-dry weight (W/D) ratio and the CFU of Candida after a Candida infection. Male BALB/c mice were injected intravenously with 107 CFU of Candida albicans. They were sacrificed by exsanguination 0, 6, 12, 18, and 24 h after infection. The lung W/D ratio was determined in order to assess the severity of pulmonary edema. BAL was performed 3 times with 0.5 ml of sterile saline. The lung W/D ratio increased significantly 24 h after the injection of Candida, and the neutrophil counts in the BAL fluid increased significantly 12, 18, and 24 h after Candida injection. To assess the effect of neutrophils on Candida-induced acute lung injury, we investigated that of neutrocytosis and neutropenia on cell counts in BAL fluid, of the W/D ratio, and of the CFU of Candida in the lung 24 h after infection. We created neutrocytotic mice using G-CSF, and neutropenic mice with cyclophosphamide. Peripheral neutrophil counts decreased significantly in cyclophosphamide-treated mice, and increased significantly in G-CSF-treated mice. The lung W/D ratio increased significantly in cyclophosphamide-treated mice. Neutrophil counts in BAL fluid increased significantly in G-CSF-treated mice, and decreased significantly in cyclophosphamide-treated mice. The CFU of Candida in the lung decreased significantly in G-CSF-treated mice, and increased significantly in cyclophosphamide-treated mice. We concluded that neutrophils play a protective role in Candida albicans-induced acute lung injury.

Solid-pseudopapillary tumor of the pancreas: immunohistochemical localization of neuroendocrine markers and CD10.

To clarify the neuroendocrine differentiation and CD10 expression in solid-pseudopapillary tumors (SPTs) of the pancreas, we performed immunohistochemical analysis in 19 such tumors, including one solid-pseudopapillary carcinoma (SPC), along with 20 pancreatic neuroendocrine tumors (PNTs), six acinar cell carcinomas (ACCs), and one pancreatoblastoma (PB). We used antisera directed against CD56, synaptophysin, protein gene product 9.5, the alpha-subunit of Go protein, chromogranin A, CD10, trypsin, chymotrypsin, various cytokeratins (CKs), CA19-9, vimentin, and alpha-1-antitrypsin (AAT). All SPTs exhibited immunoreactivity for CD56 and CD10, and 15 expressed other neuroendocrine markers focally with the exception of chromogranin A. Frequent clustering of synaptophysin-positive cells was noted. Two cases contained a peculiar nodule that cytomorphologically and immunohistochemically resembled PNT. CD10-positive cells were scarce in one SPC. PNTs were CD56-positive, but often with faint intensity, and staining for other neuroendocrine markers, including chromogranin A, was diffusely positive. CD10 was detected, mostly in a focal pattern, in five PNTs. Pan-CK, CK8, CK18, and CK19 were more frequently demonstrated in PNT than SPT. Vimentin and AAT were often identified in PNT as well and were not specific for SPT. ACCs were CD56-negative, with the exception of one case designated as a mixed acinar-endocrine carcinoma. PB was focally positive for CD56 at the periphery of the tumor nests. Four ACCs and one PB exhibited focal CD10 reactivity. This study demonstrated the unique immunohistochemical features of SPT. Our results also suggest that SPT exhibits, at least focally, neuroendocrine differentiation, and that these neuroendocrine markers and CD10 are diagnostically useful.

Single unit responses of human cutaneous mechanoreceptors to air-puff stimulation.

OBJECTIVE: To investigate responsiveness of human cutaneous mechanoreceptor to selective tactile stimuli produced by brief air-puff stimulation. METHODS: Using percutaneous microneurography, activities of single sensory units innervating glabrous skin of the hand were recorded, and air-puff stimuli with a short rise time (0.5 ms), generated by a high-speed air control system, were applied to the receptive field. Receptor activation time was estimated as the latency difference between electrically and air-puff evoked responses. RESULTS: Thirty units were analyzed: all 4 kinds of mechanoreceptors of human glabrous skin (fast adapting type 1 [FA I, n=7], fast adapting type 2 [FA II, n=4], slowly adapting 1 [SA I, n=5] and slowly adapting 2 [SA II, n=14]) were activated by air-puff stimulation. Estimated receptor activation times were 0.6-6.2 ms (mean 2.2 ms). FA II units occasionally responded twice or more to a single air-puff stimulus. CONCLUSIONS: Brief air-puffs can activate all 4 human cutaneous mechanoreceptors, and the receptor transduction time is estimated as approximately 2.0 ms. Properties of human mechanoreceptors can be studied using air-puff stimulation and microneurography.

Clinical features of three fatal cases of non-specific interstitial pneumonia.

We describe the clinical courses of the 3 fatal patients (2 females and 1 male) with idiopathic non-specific interstitial pneumonia (NSIP) among 24 patients with NSIP. Lung biopsies were diagnosed to be NSIP group II in all patients. The clinical courses from onset to death of these 3 patients were 41 months, 46 months, and 91 months. A follow-up chest CT demonstrated no apparent honey-comb formation. We found that i) about 20% of patients with NSIP died of respiratory failure, ii) in the chest CT findings, apparent honey-comb formation was rare even just before death, iii) prediction of the prognosis based on the histological findings was difficult. This is the first report to describe the clinical features of deceased patients with idiopathic NSIP; the incidence of fatal cases was considered to range from 10 to 20%.

"Tactile" sensory nerve potentials elicited by air-puff stimulation: a microneurographic study.

To investigate the sensory nerve responses to selective touch stimulation, sensory nerve action potentials after brief air-puffs were recorded with a microelectrode. In patients with peripheral neuropathy, those with impairment of tactile sensations had significantly smaller responses than did those without tactile impairment, suggesting receptor activation failure as well as nerve conduction failure. Brief air-puff stimulation, when combined with microneurography, could be used for evaluating the tactile receptor properties in humans.

Structural analysis of late intermediate complex formed between plasmid ColIb-P9 Inc RNA and its target RNA. How does a single antisense RNA repress translation of two genes at different rates?

The antisense Inc RNA encoded by the IncIalpha ColIb-P9 plasmid replicon controls the translation of repZ encoding the replication initiator and its leader peptide repY at different rates with different mechanisms. The initial loop-loop base pairing between Inc RNA and the target in the repZ mRNA leader inhibits formation of a pseudoknot required for repZ translation. A subsequent base pairing at the 5' leader of Inc RNA blocks repY translation. To delineate the molecular basis for the differential control, we analyzed the intermediate complexes formed between RepZ mRNA and Inc RNA(54), a 5'-truncated Inc RNA derivative. We found that the initial base pairing at the loops transforms into a more stable intermediate complex by its propagation in both directions. The resulting extensive base pairing indicates that the inhibition of the pseudoknot formation is established at this stage. Furthermore, the region of extensive base pairing includes bases different in related plasmids showing different incompatibility. Thus, the observed extensive base pairing is important for determining the incompatibility of the low-copy-number plasmids. We discuss the evolution of replication control systems found in IncIalpha, IncB, and IncFII group plasmids.

Isolated absence of F waves and proximal axonal dysfunction in Guillain-Barré syndrome with antiganglioside antibodies.

OBJECTIVES: To investigate the pathophysiology of selective absence of F waves and its relation with antiganglioside antibodies in Guillain-Barré syndrome (GBS). Some patients with GBS show the absence of F waves as an isolated conduction abnormality, which has been interpreted as demyelination in the proximal nerve segments. METHODS: In 62 consecutive patients with GBS, sequential nerve conduction and F wave studies were reviewed, and antibodies against ganglioside GM1, GM1b, GD1a, GalNAc-GD1a, GD1b, and GQ1b were measured by an enzyme linked immunosorbent assay. RESULTS: In the first electrophysiological studies, isolated absence of F waves was found in 12 (19%) patients. Sequential studies in 10 of these patients showed two electrophysiological sequel patterns; rapid restoration of F waves (six patients), and persistent absence of F waves with distal motor nerve degeneration (acute motor axonal neuropathy, four patients). None of the 10 patients showed evidence of demyelination in the proximal, intermediate, or distal nerve segments throughout the course. Of the 62 patients, IgG antibodies against GM1, GM1b, GalNAc-GD1a, or GD1b were significantly associated with the electrodiagnosis of acute motor axonal neuropathy, and patients with these antibodies more often had isolated absence of F waves than patients without them (11 of 36 (31%) v one of 26 (4%); p<0.01). Eleven of the 12 patients with isolated absence of F waves had positive serology for one or more antiganglioside antibodies. CONCLUSIONS: In GBS with antiganglioside antibodies, isolated absence of F waves is a frequent conduction abnormality especially in the early phase of the disease, and may be caused by axonal dysfunction, such as physiological conduction block or axonal degeneration at the nerve roots.

The plasmid F OmpP protease, a homologue of OmpT, as a potential obstacle to E. coli-based protein production.

OmpT, an outer membrane-localized protease of Escherichia coli, cleaves a number of exogenous and endogenous proteins during their purification. SecY, an endogenous membrane protein, is a target of this artificial proteolysis in vitro. Here we report that SecY cleavage occurs even in cell extracts from ompT-disrupted cells, if they carry an F plasmid derivative. A gene, ompP, on the F plasmid was shown to be responsible for this proteolysis. These results indicate that the absence of an F-like plasmid should be checked when choosing a host strain for E. coli-based protein production.

Axonal involvement at the common entrapment sites in Guillain-Barré syndrome with IgG anti-GM1 antibody.

If anti-GM1 antibody plays a role in the axonal damage in Guillain-Barré syndrome, the common entrapment sites may be preferentially involved with evidence of axonal dysfunction. To assess this hypothesis, we studied nerve conduction across the cubital tunnel in 44 patients. Abnormal amplitude reduction of compound muscle action potentials (CMAPs) was found in 45% of 20 immunoglobulin G (IgG) anti-GM1-positive and in 29% of 24 anti-GM1-negative patients. The time course and sequel were distinct between the two groups. In the former group, the amplitude reduction was prominent in weeks 1 to 2 and was followed by a decrease in distal CMAPs (axonal degeneration) or an increase in proximal CMAPs (resolution of conduction block). In contrast, anti-GM1-negative patients showed slower resolution with temporal dispersion. In anti-GM1-positive cases, amplitude reduction at the common entrapment site is frequent and may reflect wallerian degeneration or physiological conduction block at the nodes of Ranvier, both suggesting axonal involvement.

Dissociated small hand muscle involvement in amyotrophic lateral sclerosis detected by motor unit number estimates.

In some patients with amyotrophic lateral sclerosis (ALS), the thenar hand is more severely affected than the hypothenar hand. To quantify the dissociated involvement, we examined the motor unit number estimate (MUNE) of both the abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles in 23 patients with ALS. Whereas ALS patients had significantly smaller MUNEs than normal subjects in both muscles, the extent of motor unit loss was significantly greater in the APB than ADM. Moreover, a simple comparison of the amplitude of compound muscle action potentials (CMAPs) showed that ALS patients had significantly smaller APB/ADM ratios than normal subjects and patients with cervical spondylotic amyotrophy, bulbospinal muscular atrophy, or peripheral neuropathy. The more severe involvement of the APB probably reflects the specific pathophysiology in ALS, and possible mechanisms for the dissociated involvement are discussed.

Activity-dependent excitability changes in chronic inflammatory demyelinating polyneuropathy: A microneurographic study.

The purpose of this study was to investigate activity-dependent excitability changes in polyneuropathy and their correlation with symptomatology. First, we recorded sensory nerve action potentials (SNAPs) with an intraneural microelectrode during impulse trains in 11 patients with chronic inflammatory demyelinating polyneuropathy. When the stimulus frequency was increased to >/=20 Hz, all patients showed marked decreases in the amplitudes of averaged SNAPs (128 responses) associated with latency increases. The amplitude decreases were much greater than those in patients with axonal neuropathies. In single-unit recordings, responses showed latency increases, which were small but sufficient to cause decreases in the averaged responses. Clinical sensory impairment was correlated with the degree of preexisting conduction block or axonal loss, but not with the degree of rate-dependent amplitude decreases. Activity-dependent changes occur preferentially in demyelinating neuropathy and are a sensitive measure of demyelination. The mechanism responsible for the amplitude decreases could be conduction slowing or block caused by activity-dependent hyperpolarization.

The plasmid ColIb-P9 antisense Inc RNA controls expression of the RepZ replication protein and its positive regulator repY with different mechanisms.

The autonomous replication region of plasmid ColIb-P9 contains repZ encoding the RepZ replication protein, and inc and repY as the negative and positive regulators of repZ translation, respectively. inc encodes the antisense Inc RNA, and repY is a short open reading frame upstream of repZ. Translation of repY enables repZ translation by inducing formation of a pseudoknot containing stem-loop I, which base pairs with the sequence preceding the repZ start codon. Inc RNA inhibits both repY translation and formation of the pseudoknot by binding to the loop I. To investigate control of repY expression by Inc RNA, we isolated a number of mutations that express repY in the presence of Inc RNA. One class of mutations delete a part of another stem-loop (II), which derepresses repY expression by initiating translation at codon 10 (GUG), located within this structure. Point mutations in stem-loop II can also derepress repY translation, and the introduction of compensatory base-changes restores control of repY translation. These results not only indicate that suppressing a cryptic start codon by secondary structure is important for maintaining the translational control of repZ but also demonstrate that the position of start site for repY translation is critical for its control by Inc RNA. Thus, Inc RNA controls repY translation by binding in the vicinity of the start codon, in contrast to the control of repZ expression at the level of loop-loop interaction.

Copy number control of IncIalpha plasmid ColIb-P9 by competition between pseudoknot formation and antisense RNA binding at a specific RNA site.

Replication of a low-copy-number IncIalpha plasmid ColIb-P9 depends on expression of the repZ gene encoding the replication initiator protein. repZ expression is negatively controlled by the small antisense Inc RNA, and requires formation of a pseudoknot in the RepZ mRNA consisting of stem-loop I, the Inc RNA target, and a downstream sequence complementary to the loop I. The loop I sequence comprises 5'-rUUGGCG-3', conserved in many prokaryotic antisense systems, and was proposed to be the important site of copy number control. Here we show that the level of repZ expression is rate-limiting for replication and thus copy number, by comparing the levels of repZ expression and copy number from different mutant ColIb-P9 derivatives defective in Inc RNA and pseudoknot formation. Kinetic analyses using in vitro transcribed RNAs indicate that Inc RNA binding and the pseudoknot formation are competitive at the level of initial base paring to loop I. This initial interaction is stimulated by the presence of the loop U residue in the 5'-rUUGGCG-3' motif. These results indicate that the competition between the two RNA-RNA interactions at the specific site is a novel regulatory mechanism for establishing the constant level of repZ expression and thus copy number.

[Swyer-James syndrome with pneumothorax].

We report a case of Swyer-James syndrome with pneumothorax. A 20 year-old man was admitted to our hospital with dyspnea. Right pneumothorax was diagnosed by chest X-ray. He had a history of current pneumonia in childhood. After improvement of the pneumothorax, chest X-ray revealed hyperlucency of the right upper lung. Chest-CT revealed a low attenuation area and a cystic space in the right upper lobe. Xenon-133 clearance was delayed in ventilation scintigraphy. Bronchography showed cylindrical bronchiectasis in the proximal bronchi and poor filling of the peripheral bronchi in the right upper lobe. Pulmonary angiography showed a small right upper pulmonary artery. Swyer-James syndrome was diagnosed. The pneumothorax was probably caused by weakness of the cystic spaces.

An RNA pseudoknot as the molecular switch for translation of the repZ gene encoding the replication initiator of IncIalpha plasmid ColIb-P9.

Translation initiation of the repZ gene encoding the replication initiator of plasmid ColIb-P9 is not only negatively regulated by the action of the antisense Inc RNA encoded in the leader region, but is also coupled to the translation and termination of a transcribed leader sequence, repY, a positive regulatory element for repZ gene expression. This translational coupling depends on base pairing between two complementary sequences, 5'-rGGCG-3' and 5'-rCGCC-3', which are located upstream of and in the middle of repY, respectively, and have the potential to form a pseudoknot with the stem-loop structure I. Another stem-loop called structure III near the 3'-end of repY sequesters both the 5'-rCGCC-3' sequence and the repZ ribosome-binding site. Here we show that the RepZ mRNA leader sequence synthesized in vitro indeed contains several stem-loop structures including structures I and III, but not the pseudoknot. However, disruption of structure III, without changing the repZ ribosome-binding site, by means of base substitution and deletion induces base pairing between the two short complementary sequences distantly separated, resulting in the formation of a pseudoknot. When the pseudoknot is allowed to form in vivo due to the same mutations, a maximum level of repZ expression is obtained comparable to one observed in the absence of Inc RNA. These results strengthen our previously proposed model that the pseudoknot induced by the translation and termination of the repY reading frame functions as the molecular switch for translational initiation of the repZ gene.