[Retrospective study on clinical manifestation, thigh MRI and electrophysiology characteristics of immune-mediated necrotizing myopathy]

Objective: To summarize the clinical, thigh magnetic resonance (tMRI) and electromyographic (EMG) characteristics in patients with immune-mediated necrotizing myopathy (IMNM). Methods: A total of 32 IMNM patients who were admitted to the Department of Neurology from April 2019 to April 2021 were enrolled at the First Medical Centre of Chinese PLA General Hospital. According to the type of antibody, the patients were divided into anti-SRP antibody positive (SRP⁺) group, anti-HMGCR antibody positive (HMGCR⁺) group and seronegative (SN) group. The gender, age, course of disease, myositis antibodies, extramuscular manifestations, EMG were collected and analyzed among three groups. The characteristics of skeletal muscle were assessed by tMRI inflammatory edema and fat infiltration scores. Analysis of variance, Kruskal-Wallis test and Chi-square test were used to compare the differences in different clinical characteristics and tMRI scores among the three groups. When there was a statistical difference among the three groups, the comparison between the two groups was corrected by the Bonferroni method. Result: (1) Of the 32 patients, 20 were females (62.5%).The median age of onset was 47±14 years, 25 (78.1%) patients had an acute or subacute course.There were 17 (53.1%) with SRP⁺, 8 (25.0%) with HMGCR⁺, and 7 (21.9%) with MSAs (myositis specific antibodies) negative. Anti-Ro52 antibody was the most common combined antibody (12/32, 37.5%), among which 10 were in SRP⁺group.(2) The CK of all patients were elevated, median was 5 948 (4 229, 7 664) U/L. There was no statistical difference of MMT scores among three groups. The proximal limb score was lower than distal limb (P<0.01). The axial muscle score was lower than the distal limb score (P<0.05).(3) Extramuscular manifestations of HMGCR⁺ group were lower than those of the other two groups (12.5% vs. 71.4% and 76.5%, P<0.017). Rash (60.0% vs.14.3%, P<0.05) and interstitial pulmonary diseases (70.0% vs. 14.3%, P<0.05) were more common in patients with anti-SRP coexistence with anti-Ro52 than those with isolated anti-SRP. Connective tissue disease was more common in SN group (57.1% vs. 11.8% and 0, P<0.017).(4) tMRI showed fascial edema of SN group was more obvious than that of the other two groups (P<0.017). There was no statistical difference in the degree of fat infiltration and inflammatory edema among three groups, but SRP⁺ group had more cases of early fat infiltration.(5) Myotonic potentials (25.0% vs. 0 and 0, P<0.017) and compound repetitive discharges (CRDs) (50.0% vs. 5.9% and 0, P<0.017) were common in HMGCR⁺ group. Proteomic analysis found significantly different expressed proteins in skeletal muscle of patients with myotonic potentials or CRDs were associated with cytoskeleton, cell junction and extracellular matrix. Conclusion: IMNM with pure anti-SRP antibody positive and anti-HMGCR positive were mainly affected by skeletal muscles. Those who were co-positive for anti-SRP antibody and anti-Ro52 antibody had more extramuscular manifestations, which might be a special subtype of SRP⁺ group. This study proposed for the first time that myofascial inflammatory edema is an early sign of SN-IMNM injury. EMG of HMGCR⁺group were more prone to myotonia potential and CRDs.

Neuromagnetic evidence of abnormal automatic inhibitory function in subjective memory complaint

Subjective memory complaint (SMC), a self-perceived worsening in memory capacity concurrent with normal performance on standardized cognitive assessments, is considered a risk factor for the development of Alzheimer's disease (AD). Deficient sensory gating (SG), referring to the lack of automatic inhibition of neural responses to the second identical stimulus, has been documented in prodromal and incident AD patients. However, it remains unknown whether the cognitively normal elderly with SMC demonstrate alterations of SG function compared with those without SMC. A total of 19 healthy controls (HC) and 16 SMC subjects were included in the present study. Neural responses to the auditory paired-stimulus paradigm were recorded by the magnetoencephalography and analyzed by the distributed source imaging method of minimum norm estimate. The SG of M50 and M100 components were measured using the amplitude ratio of the second response over the first response at the cortical level. Compared to HC, subjects with SMC showed significantly increased M50 SG ratios in the inferior parietal lobule (IPL). Furthermore, M50 SG ratios in the right IPL yielded an acceptable discriminative ability to distinguish SMC from HC. However, we did not find a significant association between SG ratios and cognitive function requiring inhibitory control either in the HC or SMC group. In conclusion, although SMC subjects have intact cognitive functioning revealed by objective neuropsychological tests, their deficits in automatic inhibitory function could be detected through neurophysiological recordings. Our results suggest that altered brain function occurs in SMC prior to the obvious decline of cognitive performance.

Age Effects on Spatiotemporal Dynamics of Response Inhibition: An MEG Study

Inhibition, the ability to suppress irrelevant information, thoughts or movements, is crucial for humans to perform context-appropriate behaviors. It was suggested that declined cognitive performance in older adults might be attributed to inhibitory deficiencies. Although previous studies have shown an age-associated reduction in inhibitory ability, the understanding regarding its cortical spatiotemporal maps remained limited. Thus, we used a whole-head magnetoencephalography (MEG) to elucidate the age effects on response inhibition, and to explore the brain activation differences in high- and low-performing seniors. We recruited 22 younger and 22 older adults to participate in the visual Go/No-go task. Both behavioral performance and neuromagnetic responses to No-go stimuli were analyzed. The behavioral results showed that the older adults made more false alarm (FA) errors than the younger adults did. The MEG results showed that the seniors exhibited declined cortical activities in middle temporal gyrus (MTG) and delayed activation in MTG, prefrontal cortex (PFC) and pre-supplementary motor area (pre-SMA). Furthermore, among the older adults, more recruitment of the left PFC was found in the high-performers than in the lower-performers. In conclusion, age-related deficiencies in response inhibition were observed in both behavioral performance and neurophysiological measurement. Our results also suggested that frontal recruitment plays a compensatory role in successful inhibition.

The β-adrenoceptor blocker propranolol ameliorates compulsive-like gambling behaviour in a rodent slot machine task: implications for iatrogenic gambling disorder

Previous work has shown that chronic administration of the dopamine D_2/3 receptor agonist ropinirole invigorates performance on a rodent slot machine task (rSMT). This behavioural change appears superficially similar to the iatrogenic gambling disorder (GD) observed in a sub-set of patients with Parkinson's disease (PD), and has been associated with increased activation of the intra-cellular signalling proteins GSK3β and CREB in the striatum. Here, we wanted to determine whether this response to ropinirole could be attenuated by targeting these signalling proteins, and if the loss of dopaminergic innervation characteristic of PD would alter ropinirole's effects on the rSMT. Male Long Evans rats were trained on the rSMT. Dopaminergic terminals innervating the dorsolateral striatum were then lesioned bilaterally using the neurotoxin 6-hydroxydopamine hydrochloride (6-OHDA). Subsequently animals were implanted with osmotic mini-pumps delivering ropinirole. Lastly, animals were given dietary lithium (Li⁺ ), to inhibit the activation of GSK3β, or injections of the ß-adrenoceptor antagonist propranolol, which potently inhibits CREB as a secondary mechanism of action, and any changes in ropinirole-induced increases in compulsive-like engagement in the rSMT evaluated. Chronic ropinirole increased the number of trials animals completed, reproducing our original finding. This increase in task engagement was not altered in animals with 6-OHDA lesions, a putative model of early PD. In addition, the effects of ropinirole were not attenuated by administration of Li⁺ , but were ameliorated by propranolol. These data suggest that propranolol may represent a potential pharmacotherapy for the treatment of iatrogenic gambling.

Age Effect on Automatic Inhibitory Function of the Somatosensory and Motor Cortex: An MEG Study

Age-related deficiency in the top-down modulation of cognitive inhibition has been extensively documented, whereas the effects of age on a bottom-up or automatic operation of inhibitory function were less investigated. It is unknown that whether the older adults (OA)’ reduced behavioral performance and neural responses are due to the insufficient bottom-up processes. Compared to behavioral assessments which have been widely used to examine the top-down control of response inhibition, electrophysiological recordings are more suitable to probe the early-stage processes of automatic inhibitory function. Sensory gating (SG), a phenomenon of attenuated neural response to the second identical stimulus in a paired-pulse paradigm, is an indicator to assess automatic inhibitory function of the sensory cortex. On the other hand, electricity-induced beta rebound oscillation in a single-pulse paradigm reflects cortical inhibition of the motor cortex. From the neurophysiological perspective, SG and beta rebound oscillation are replicable indicators to examine the automatic inhibitory function of human sensorimotor cortices. Thus, the present study aimed to use a whole-head magnetoencephalography (MEG) to investigate the age-related alterations of SG function in the primary somatosensory cortex (SI) and of beta rebound oscillation in the primary motor cortex (MI) in 17 healthy younger and 15 older adults. The Stimulus 2/Stimulus 1 (S2/S1) amplitude ratio in response to the paired-pulse electrical stimulation to the left median nerve was used to evaluate the automatic inhibitory function of SI, and the beta rebound response in the single-pulse paradigm was used to evaluate the automatic inhibitory function of MI. Although there were no significant age-related differences found in the SI SG ratios, the MI beta rebound power was reduced and peak latency was prolonged in the OA. Furthermore, significant association between the SI SG ratio and the MI beta rebound power, which was seen in the younger adults (YA), was absent in the OA. In conclusion, our data suggested an age-related defect of association between sensorimotor cortices regarding automatic inhibitory function.

The agranular and granular insula differentially contribute to gambling-like behavior on a rat slot machine task: effects of inactivation and local infusion of a dopamine D4 agonist on reward expectancy

RATIONALE

Rats, like humans, are susceptible to the reinforcing effects of reward-related stimuli presented within a compound stimulus array, putatively analogous to the so-called near-miss effect. We have previously demonstrated using a rodent slot machine task (rSMT) that the reward expectancy these stimuli elicit is critically mediated by the dopamine D4 receptor. D4 receptors are principally located in prefrontal regions activated during slot machine play in humans, such as the insular cortex. The insula has recently attracted considerable interest as it appears to play a crucial role in substance and behavioral addictions. However, the insula is a heterogeneous area, and the relative contributions of subregions to addictive behaviors are unclear.

METHODS

Male Long Evans rats were trained to perform the rSMT, and then bilateral cannula targeting either the granular or agranular insula were implanted. The effects of inactivation and local administration of a D4 agonist were investigated.

RESULTS

Temporary inactivation of the agranular, but not the granular insula impaired performance on the rSMT. In contrast, local infusion of the D4 agonist PD168077 into the agranular insula had no effect on task performance, but when administered into the granular insula, it improved animals' ability to differentiate winning from non-winning trials. The agranular insula may therefore modulate decision making when conflicting stimuli are present, potentially due to its role in generating a cohesive emotional percept based on both externally and internally generated signals, whereas the granular insular is not critical for this process. Nevertheless, D4 receptors within the granular insula may amplify the incentive salience of aversive environmental stimuli.

DISCUSSION

These data provide insight into the neurobiological mechanism underpinning maladaptive reward expectancy during gambling and provide further evidence that D4 receptors represent a potential target for developing pharmacotherapies for problem gambling.

Involvement of adrenomedullin in spinal glial activation following chronic administration of morphine in rats

BACKGROUND

Adrenomedullin (AM) belongs to the calcitonin gene-related peptide (CGRP) family. Our previous studies show that chronic exposure to morphine increases spinal AM bioactivity, contributing to the development and maintenance of morphine tolerance. This study investigated the possible involvement of AM in morphine-evoked gliosis.

METHODS

Real-time polymerase chain reaction was performed to determine interleukin-1β (IL-1β), IL-6 and tumour necrosis factor-α (TNF-α) mRNAs in the spinal dorsal horn and cultured sensory ganglion explants. Immunohistochemistry was performed to identify spinal microglia and astrocytes.

RESULTS

Repetitive intrathecal (i.t.) injection of morphine (20 μg) increased the expression of IL-1β, IL-6 and TNF-α mRNAs in the spinal dorsal horn. The co-administration of the selective AM receptor antagonist AM22-52 (36 μg) markedly attenuated chronic morphine-evoked increase in IL-1β and IL-6, but not TNF-α, mRNA levels. Exposure of cultured dorsal root ganglion (DRG) explants to morphine (3.3 μmol/L) for 6 days up-regulated IL-1β and IL-6 mRNA expressions. The depletion of AM gene using small interfering RNA (siRNA) approach abolished morphine-evoked increase in IL-1β and IL-6 syntheses in the cultured DRG. The blockade of AM receptors by i.t. AM22-52 also inhibited chronic morphine-evoked cell hypertrophy of microglia and astrocytes as well as an increase in OX-42 and GFAP (glial fibrillary acidic protein) immunoreactivities. Furthermore, the 6-day treatment with AM (10 μg, i.t.) induced morphological changes of microglia and astrocytes as well as an increase in IL-1β, IL-6 and TNF-α mRNA levels in the spinal dorsal horn.

CONCLUSION

The present study supports the idea that up-regulation of the pronociceptive mediator AM can recruit spinal glial cells, resulting in an increase in cytokines during chronic use of morphine.

Prevention and Reversal of Diabetes by All-Trans Retinoid Acid and Exendin-4 in NOD Mice

It has been shown that all-trans retinoid acid (ATRA) hinders the development of autoimmune diabetes by inducing immune tolerance status. Meanwhile, exendin-4 increases beta-cell function and mass. Thus, we hypothesized that ATRA and exendin-4 combination therapy would prevent and reverse autoimmune diabetes. NOD/scid mice were intravenously transferred with splenocytes isolated from 12-week-old female NOD mice. After adoptive transfer, mice were treated with vehicle, ATRA (0.5 mg/mouse intraperitoneally every other day), exendin-4 (3  μ g/kg subcutaneously twice daily), or combination for 6 weeks. Compared with vehicle, ATRA (P = 0.022) and ATRA plus exendin-4 (P = 0.013) treatment delayed the onset of diabetes. The pancreatic insulin content in mice treated with ATRA (P = 0.013) and exendin-4 (P < 0.02) was significantly higher than that of control mice. All but one spontaneous diabetic NOD mouse treated with ATRA and/or exendin-4 remained persistent hyperglycemic. ATRA and/or exendin-4 treatment did not alter their blood glucose levels and survival. Our results indicate that, before the onset of autoimmune diabetes, ATRA and exendin-4 treatment alone preserves pancreatic beta cells; ATRA and ATRA plus exendin-4 treatment delays the onset of autoimmune diabetes. However, after the onset of autoimmune diabetes, ATRA and/or exendin-4 treatment is unable to reverse hyperglycemia or improve survival.

Quantitative NanoProteomics approach for protein complex (QNanoPX) using gold nanoparticle-based DNA probe

Affinity purification by pulldown methods using target-bound gel beads provides a powerful approach for purifying endogenous protein complexes. Such methods can be improved by using nanoparticle-based probe, coupled with immunoblot analysis or quantitative proteomics method using stable isotope labeling via liquid chromatography-mass spectrometry (LC-MS). Here, we describe sample preparation and a pulldown method using gold nanoparticle-based DNA probe for characterizing the transcriptional complex of estrogen response element (ERE). The described protocol includes the fabrication of gold nanoparticle-based probe, nuclear extract preparation, and affinity purification for the analysis by immunoblotting, as well as the subsequent trypsin digestion and stable isotope dimethyl labeling for the analysis by LC-MS.

Generalized reticulated hyperpigmentation induced by lichen planus

A 68-year-old Chinese woman presented with generalized reticulated dark-brown hyperpigmentation on the trunk, face and limbs, oral Wickham's striae, sparse scalp hair and dark-red reticulated streaks on the occiput of the head and on the neck, some dark-red to violaceous papules on the face, scalp and flanks, light-yellow, deep-seated papules on the palms and soles, and small porcelain-white papules on the dorsal and lateral fingers. The histological features were consistent with the diagnosis of lichen planus (LP). To our knowledge, LP-induced generalized reticulated hyperpigmentation is very rare and this is the first report of the clinical features on the fingers, palms and soles.

Human gastric cells resistant to (−)-epigallocatechin gallate show cross-resistance to several environmental pollutants

After a long-term culture in (-)-epigallocatechin gallate (EGCG, 20 microM), a major constituent of green tea, human gastric AGS cells developed 2.2-fold resistance to EGCG. The resistant AGS (AGS-R) cells were cross-resistant to several N-methylcarbamate insecticides, which are among the major control agents for pest insects in Taiwan. The AGS-R cells also showed protective effects against both the cytotoxicity and DNA damage induced by one of the mutagenic derivatives of N-methylcarbamate insecticide, N-nitroso methomyl, which is known to target the mammalian gastric tract. Therefore, acquisition of resistance by AGS cells through chronic exposure to EGCG implies that the tea-drinking habit of the Taiwanese is probably beneficial for the health of the gastric tract. In addition, AGS-R cells were cross-resistant to sodium arsenite and hydrogen peroxide, indicating that tolerance to oxidative stress might play a role in the development of resistance described in this investigation.

Effective Structure Factor of Osmotically Deformed Nanoemulsions

Extreme osmotic compression of nanoemulsion droplets, achieved by ultracentrifugation, can create solidlike biliquid foams without causing significant droplet coalescence. Using small-angle neutron scattering (SANS), we probe the structure of a uniform silicone oil-in-water nanoemulsion stabilized by sodium dodecyl sulfate over a wide range of volume fractions, phi, up to and beyond the limit associated with maximal random jamming of spheres, phiMRJ = 0.64. Although some features in the structure can be understood at lower phi using simple predictions for hard spheres, the anionic repulsion and deformability of the droplet interfaces creates departures from these predictions at higher phi. For phi near and beyond phiMRJ, the effective structure factor, Seff, as a function of wavenumber, q, exhibits a primary peak that is subunity. We speculate that this striking feature is due to the deformation of the droplets into nonspherical shapes as the system begins to approach the limit of a random array of nanoscopic thin films, Plateau borders, and vertexes characteristic of a polyhedral foam.

Dense cluster formation during aggregation and gelation of attractive slippery nanoemulsion droplets

Using time-resolved small angle neutron scattering, we have measured the wave-number-dependent structure factor S(q) of monodisperse nanoemulsions that aggregate and gel after we suddenly turn on a strong, short-range, slippery attraction between the droplets. At high q, peaks in S(q) appear as dense clusters of droplets form, and S(q) increases strongly toward low q, as these dense clusters become locked into a rigid gel network, despite the fluidity of the films between the droplets. The long-time high-q structure of nanoemulsion gels formed by slippery diffusion-limited cluster aggregation is universal in shape and remarkably independent of the droplet volume fraction, phi.

Structure of concentrated nanoemulsions

We use extreme shear to create a dispersion of nanoscale droplets of silicone oil in an immiscible water phase containing an anionic surfactant sodium dodecylsulfate. Using centrifugal size fractionation, we obtain nanoemulsions having a well-defined average radius of a=75 nm. We measure the structure of concentrated nanoemulsions over a wide range of volume fractions, 0<phi<0.6, using small angle neutron scattering, and we determine the structure factor S(q) of disordered glassy dispersions of uniform deformable droplets interacting through screened surface charge repulsions. Although the low-q behavior of S(q,phi) resembles that predicted for hard spheres, the height of the primary peak does not. Instead, it exhibits a maximum as phi is increased. This difference cannot be explained solely by the droplet size polydispersity and is likely related to the deformability of the droplets that have been locked into a glassy structure.

Density profiles of temperature-sensitive microgel particles

We have performed small angle neutron scattering measurements (SANS) on dilute aqueous dispersions of polymer microgel particles as a function of temperature, T . The microgel particles are spherical crosslinked assemblies of a loose gel network of a poly-N-isopropylacrylamide (NIPAM) polymer. When the temperature is raised beyond a critical temperature, T(lc) approximately 32 degrees C , the polymer becomes more strongly attracted to itself than the solvent, and the microgel particles contract. The measured form factor, F (q) , for dilute suspensions of uniform microgel particles exhibits many peaks that are characteristic of solid polymer nanospheres. The position and amplitude of the peaks as a function of wave number, q , provide insight into the density profile of poly-NIPAM within the microgels. These peaks can be described well over a wide range of temperature by a model of the polymer density within the particles that is constant up to an inner radius, R1 , and decreases linearly to zero at an outer radius, R2 .

Genetic diversity and biogeography of Cunninghamia konishii (Cupressaceae), an island species in Taiwan: a comparison with Cunninghamia lanceolata, a mainland species in China

Luanta-fir (Cunninghamia konishii), an endemic to Taiwan, is an outcrossing, long-lived conifer. Populations of C. konishii are generally fragmented due to a once high intensity of timber exploitation. C. konishii and Cunninghamia lanceolata are two sibling taxa constituting derivative-progenitor species relationship. The amount of genetic variations within and between 11 and 10 populations of C. konishii and C. lanceolata, respectively, were assessed using amplified fragment length polymorphism (AFLP) markers in this report. Three AFLP primer pairs generated a total of 357 and 226 markers for C. konishii and C. lanceolata samples, of which 56.1 and 65.3% are polymorphic, respectively. Analysis of molecular variance indicates a 4.78% variation between C. konishii and C. lanceolata. A relatively high value of genetic variation (24.60%) was apportioned between the populations of C. konishii. In contrast, a lower divergence value (12.21%) between populations was found for C. lanceolata. The population with the highest genetic diversity was found in Nantou County, which concurred with the results of many other tree species investigated in Taiwan. The estimates of the number of migrants between populations (Nm), obtained from population pair-wise PhiST, suggest that gene flow in C. konishii is efficient in some adjacent populations but is restricted in the rest. Individual UPGMA tree, generated based on AFLP markers, suggests six evolutionary lineages for C. konishii. All evolutionary lineages of C. konishii were derived from C. lanceolata. In conclusion, the migration patterns of Cunninghamia from mainland China may have been established following multiple sources, migrant-pools, long-distance dispersal events, and via different directions.

Asphaltene nanoparticle aggregation in mixtures of incompatible crude oils

We study the structure and phase behavior of asphaltenes comprised of large polyaromatic molecules in blends of naturally occurring crude oils using small angle neutron scattering (SANS). When two compatible oils are blended together, the asphaltenes remain dispersed as colloidal nanoparticles; however, when two incompatible oils are blended together, these asphaltene nanoparticles can aggregate to form microscale structures. We show that SANS directly probes asphaltene aggregation in unmodified (i.e., nondeuterated) crude oil mixtures due to a significant neutron scattering length density difference between the hydrogen-poor asphaltenes and the surrounding oil. Moreover, the small length scales probed by SANS are ideally suited for studying asphaltene aggregation: SANS simultaneously provides the average size and concentration of nanoscale asphaltene particles and also the volume fraction of microscale asphaltene aggregates. These discoveries yield a practical means for directly assessing the compatibility of crude oils and for diagnosing refinery fouling problems resulting from blending incompatible oils.

Increase of viability of entrapped cells of Lactobacillus delbrueckii ssp. bulgaricus in artificial sesame oil emulsions

A technique was developed to protect lactic acid bacteria (Lactobacillus delbrueckii ssp. bulgaricus) against simulated gastrointestinal conditions by encapsulation of bacterial cells within artificial sesame oil emulsions. Purified sesame oil bodies consisting of approximately 99% oil, 0.5% phospholipid, and 0.5% protein were decomposed by heating at 70 degrees C for 1 h. The bacteria cultured in nonfat milk were encapsulated in artificial oil emulsions constituted with decomposed sesame oil bodies and excess sesame or vegetable cooking oil. Viability of bacteria in storage at 4 degrees C for 16 d was substantially elevated from 0.023 to 5.45% after encapsulation. Compared with free cells, the entrapped bacteria demonstrated a significant increase (approximately 10(4) times) in survival rate when subjected to simulated high acid gastric or bile salt conditions. The results indicate that artificial sesame oil emulsion may serve as an effective biocapsule for encapsulation of bacteria in dairy products.

Immunohistochemical analysis of epidermal growth factor receptor family members in stage I non-small cell lung cancer

BACKGROUND

To elucidate the relationship between the expression of epidermal growth factor receptor family members (ErbB-1, neu/ErbB-2, ErbB-3, and ErbB-4) and tumor recurrence.

METHODS

We used immunohistochemistry to examine the expression of four epidermal growth factor receptor family members in 73 patients with stage I non-small cell lung cancer.

RESULTS

Using Cox univariate analysis, we determined that angiolymphatic tumor emboli and non-well-differentiated tumor cells were two significant conventional pathologic predictors of tumor recurrence, and that ErbB-1 and ErbB-3 were also significant predictors. Co-expression of ErbB-1+, -3+, or expression of three or more epidermal growth factor receptor family members had a significant effect on lung cancer recurrence. A stepwise multivariate Cox proportional hazards regression analysis provided a predictive model for tumor recurrence.

CONCLUSIONS

The present study shows that in patients with a non-well-differentiated tumor, overexpression of ErbB-3 is a useful marker for predicting tumor recurrence. The present study also confirmed that ErbB-1 expression increased in proportion to the loss of tumor differentiation. The correlation between ErbB-3 and distant metastasis was good.

Molecular characterization of Newcastle disease viruses isolated from recent outbreaks in Taiwan

A reverse transcription-polymerase chain reaction (RT-PCR) was described which amplified a portion of the F and HN genes of Newcastle disease virus (NDV) isolated from recent outbreaks in Taiwan. The F protein plays an important role in determining the virulence of NDV strains. Sequencing of a region specifying the F protein cleavage site was therefore undertaken and this verified the correlation between deduced amino sequences and pathogenicity. Analysis of the deduced amino acid sequences of the F protein cleavage site showed that all recent Taiwanese isolates in 1999 were velogenic viruses. All the virulent viruses have the amino acid sequence 112RRQKR116 for the C-terminus of the F2 protein and phenylanine (F) at the N-terminus of the F1 protein, residue 117. A phylogenetic tree based on the nucleotide sequences of the F gene revealed that recent Taiwanese NDV isolates responsible for recent outbreaks were classified into two distant genotypes (VI and VII). Genotype VI virus is the first finding in Taiwan and has a highly genetic similarity to European isolates, suggesting that they might have originated from a common ancestor.

Molecular characterisation of very virulent infectious bursal disease viruses in Taiwan

The very virulent infectious bursal disease virus (vv IBDV) RNA in the bursa of Fabricius and spleen from experimentally infected chickens or field samples was detected by in situ hybridisation (ISH) with subsequent reverse transcription (RT)-polymerase chain reaction (PCR) and sequence analysis. The VP 2 gene of vv IBDV was detected by ISH in infected chicken tissues with a cloned digoxigenin (DIG)-labelled cDNA probe. To verify ISH, RT - PCR was used to amplify two 643- and 500-base pair fragments on the VP 2 gene of IBDV in the bursa of Fabricius. With all isolates, two c DNA fragments of 643 and 500 bp long, respectively, were generated as expected and further confirmed the specificity of ISH. Analysis of the hypervariable region (HVR) of the VP 2 gene revealed that a serine-rich heptapeptide SWSASGS located at amino acids 326-332 was conserved in recent Taiwanese strains, and two amino acid substitutions were found in the classical Taiwanese strains at positions 330M and 331W. Three amino acids were unique to the vv strains at positions 222A, 256I and 294I, compared with classical and variant strains. Sequence and phylogenetic analysis showed that the recent Taiwanese strains were closely related, very similar to vv IBDV s from Europe, China, Japan, and Africa, and distantly related to the Taiwanese classical strains.

Attrition of bystander CD8 T cells during virus-induced T-cell and interferon responses

Experiments designed to distinguish virus-specific from non-virus-specific T cells showed that bystander T cells underwent apoptosis and substantial attrition in the wake of a strong T-cell response. Memory CD8 T cells (CD8(+) CD44(hi)) were most affected. During acute viral infection, transgenic T cells that were clearly defined as non-virus specific decreased in number and showed an increase in apoptosis. Also, use of lymphocytic choriomeningitis virus (LCMV) carrier mice, which lack LCMV-specific T cells, showed a significant decline in non-virus-specific memory CD8 T cells that correlated to an increase in apoptosis in response to the proliferation of adoptively transferred virus-specific T cells. Attrition of T cells early during infection correlated with the alpha/beta interferon (IFN-alpha/beta) peak, and the IFN inducer poly(I:C) caused apoptosis and attrition of CD8(+) CD44(hi) T cells in normal mice but not in IFN-alpha/beta receptor-deficient mice. Apoptotic attrition of bystander T cells may make room for the antigen-specific expansion of T cells during infection and may, in part, account for the loss of T-cell memory that occurs when the host undergoes subsequent infections.

Pathogenicity and drug susceptibility of the Pasteurella anatis isolated in chickens in Taiwan

A strain of Pasteurella anatis (PA) was isolated from the sinus of an adult leghorn laying chicken with sinusitis, nasal discharge, drop in egg production, and low mortality, symptoms initially thought to indicate infectious coryza. The tiny, smooth, whitish colonies were identified as PA. To compare its pathogenicity with that of commercial broilers, nine groups, 10 birds per group, of 10-day-old broilers were individually inoculated with the strain of PA, Pasteurella multocida (PM), or Escherichia coli (EC) by intravenous, intraperitoneal, intramuscular, or subcutaneous inoculation. The PA was determined to cause the signs, lesions, and septicemic death, which are similar to the symptoms of PM or EC infection. At 1 wk postinfection (PI), the mortality rate was between that of PM and EC infection at 1 wk PI. Twenty antimicrobial-containing discs were evaluated, and the isolate was highly sensitive to cetiofer, amoxicillin, lincopectin, and furazolidone. Furthermore, it was moderately sensitive to tetracycline and enrofloxacin and only slightly sensitive to cephalothin, chloramphenicol, flumequine, nalidixic acid, neomycin, oxolinic acid, streptomycin, and trimethoprim. The PA infection was treated successfully with amoxicillin.

Redoing reconstruction of the esophagus using remnants of the ileo-left colon aided by microvascular anastomosis

Theoretically, the jejunum, fasciocutaneous or myocutaneous flap is recommended as an esophageal substitute in redoing reconstruction of the esophagus after a second incidence of corrosive injury. However, other esophageal substitutes should also be considered. We present a case of a 42-year-old woman who underwent esophageal reconstruction using an ileocolon graft for corrosive esophageal stricture ten years before. The patient ingested caustic drain cleaner again and underwent resection of the ileocolon graft secondary to corrosive necrosis. Two and a half months after the second incidence of corrosive injury, reconstruction of the esophagus was again performed using a graft of remnant ileo-left colon aided by microvascular anastomosis. The patient was able to swallow a regular diet after the procedure. Remnant ileo-left colon is a good alternative esophageal substitute in cases of repeated corrosive injury.

Esophageal reconstruction for hypopharyngoesophageal strictures after corrosive injury

OBJECTIVE

To evaluate the surgical outcome of patients with caustic stricture of the hypopharyngoesophagus.

MATERIALS AND METHODS

During a 25-year period, we performed esophageal reconstruction in 152 patients with diffuse or multiple caustic esophageal stricture. Of them, esophageal substitute was pulled up and anastomosed to the hypopharynx in 50 (33%) patients, and anastomosed to the cervical esophagus in the other 102 (67%) patients. Patients whose esophageal substitute anastomosed to the hypopharynx were enrolled to the present study. Among these 50 study patients, 13 underwent ablation of damaged organs and feeding jejunostomy in acute stage of corrosive injury, and the remaining 37 patients were initially organ preserved with or without feeding gastrostomy or jejunostomy. Six patients had respiratory distress caused by laryngotracheal stricture. The ileocolon (28/50) was commonly used as an esophageal substitute in reconstruction and most substitutes (43/50) went through the substernal route.

RESULTS

There was one operative death. Eight (16%) patients had major early postoperative complications. Six patients underwent revision for late stenosis of hypopharyngeal anastomosis, and one redoing reconstruction using the jejunum because of failure of the transplanted ileocolon. Postoperatively, swallow function and maintaining body weight were considered good in 42 patients (84%) after an average of 8 months follow-up. Five of six patients who underwent concomitant tracheostomy or laryngosurgery for laryngotracheal stricture got unsatisfactory result. The surgical outcome of the study patients was worse than that in patients with esophageal substitute anastomosed to a healthy cervical esophagus. In the later group of patients, 95/102 (93%) had good swallow function and only 7/102 (6.8%) had major early complications.

CONCLUSION

Caustic stricture of the hypopharyngoesophagus is a challenging reconstructive problem. A successful reconstruction requires a correct hypopharyngeal opening and anastomosis, a good esophageal substitute, and a patent esophageal route and airway.

Ventilator-associated pneumonia with circuit changes every 2 days versus every week

BACKGROUND

Frequent ventilator circuit changes are expensive and sometimes unnecessary. Following the worldwide trend to lengthen the intervals for ventilator circuit change from 2 days to 1 week, this study aims to assure that low rate of ventilator-associated pneumonia (VAP) can be maintained with cost containment.

METHODS

Ventilator circuits were routinely changed every 7 days in the study period for 2 years and every 2 days during the historical control period of another 2 years. Pediatric patients (age less than 15 years) were not included. Nosocomial pneumonia was diagnosed by the criteria of the Centers of Disease Control and Prevention (CDC) of the United States (US). VAP was identified by combining and comparing 2 databases from the Respiratory Therapy Department and the Infection Control Unit of our hospital.

RESULTS

In the study group, 225 episodes of pneumonias were observed in 7,068 patients and 87,338 ventilator days. The rate of VAP was 2.58 per 1,000 ventilator days. There were 174 episodes of pneumonia in 6,213 patients and 65,467 ventilator days of the control group. The rate of VAP was 2.66 per 1,000 ventilator days. The difference between both groups was not significant (p = 0.803). Yet, the cost curbed was around 80,000 US dollars per year.

CONCLUSIONS

Extending ventilator circuit change interval from 2 days to 7 days do not increase the risk for VAP, but the cost savings for labor and supply are substantial.

Surgery for lung abscess in immunocompetent and immunocompromised children

PURPOSE

The aim of this study was to evaluate the surgical management results of lung abscess in immunocompetent and immunocompromised children.

METHODS

Surgery was performed on 30 children with lung abscess or necrotizing pneumonia refractory to medical treatment in a 12-year period. Of them, 23 were immunocompetent, and 7 were immunocompromised. Pulmonary resection was performed including unilateral lung in 28, bilateral in 2, and 2 lobes in 6. Concomitant decortication was performed in 18 (78.2%) immunocompetent patients.

RESULTS

Increased incidence of surgery for lung abscess was caused mainly by drug-resistant and fungal infection. Surgery was performed commonly for bacterial lung abscess on patients less than 5 years old and fungal lung abscess on adolescence. A multiple small abscess was the predominant type of abscess in immunocompetent patients, whereas 2-lobe involvement tended to occur in immunocompromised patients. Fungal lung abscess tended to occur on left lung and in female patients. Left lower lobe was involved most commonly in both groups of patients in which majority need lobectomy. Immunocompromised patients required a more extensive pulmonary resection. There were 3 postoperative complications (morbidity of 10.2%) with no postoperative mortality. Length of postoperative hospital stay ranged from 6 to 85 days with average of 18.4 days.

CONCLUSIONS

The incidence and pattern of lung abscess that required surgery between immunocompetent and immunocompromised children were different. A more aggressive, extensive surgical procedure is preferable for immunocompromised patients, and the surgical results were comparatively excellent to immunocompetent patients. However, the prognosis of immunocompromised children depends on their underlying disease process.

Fetal thymi from diabetes-prone but not diabetes-resistant BB/Wor rats fail to generate mature ART2+ T-cells in organ culture

Diabetes-prone (BBDP) BB rats develop spontaneous autoimmune diabetes mellitus. They are lymphopenic and severely deficient in ART2+ T-cells. Diabetes-resistant BB (BBDR) rats do not develop spontaneous diabetes and have normal numbers of ART2+ T-cells. T-cell lymphopenia in BBDP rats results from hematopoietic stem cell defects leading to abnormal intrathymic T-cell maturation. To study this process, we established rat fetal thymic organ cultures (FTOC). Like mouse FTOC, cultures of BBDR rat thymi yielded approximately 10(5) cells per lobe. The majority of cells were CD8+ART2+ T-cells. In contrast, BBDP rat FTOC yielded 60% fewer cells (approximately 0.3 x 10(5)/lobe), a smaller percentage of CD8+ and TcRalphabeta+ T-cells, and almost no detectable ART2+ T-cells. ART2 mRNA was detectable in BBDR but not BBDP FTOC. In contrast, expression of mRNAs encoding bcl-2 and a panel of cytokines was comparable in BBDP and BBDR FTOC. Addition of anti-ICAM-1 (CD54) antibody reduced T-cell number in BBDR rat FTOC by approximately 70%, but addition of IL-7 or IL-1beta had no effect. The data demonstrate that BBDP thymocytes fail to generate mature ART2+ T-cells in rat FTOC, a system that can now be used to study the mechanism of this process.

Cutting edge: two distinct mechanisms lead to impaired T cell homeostasis in Janus kinase 3- and CTLA-4-deficient mice

Cytokine receptor signaling and costimulatory receptor signaling play distinct roles in T cell activation. Nonetheless, deficiencies in either of these pathways lead to seemingly similar phenotypes of impaired T cell homeostasis. A dramatic expansion of CD4(+) peripheral T cells with an activated phenotype has been observed in both Janus kinase (Jak) 3-deficient and CTLA-4-deficient mice. Despite these similarities, the mechanisms driving T cell expansion may be distinct. To address this possibility, we examined the TCR repertoire of peripheral T cells in Jak3(-/-) and CTLA-4(-/-) mice using complementarity-determining region 3 spectratype analysis. Interestingly, a restricted and highly biased TCR repertoire was observed in the Jak3(-/-) T cells, strongly supporting a role for foreign Ag in the activation and expansion of these cells. In contrast, CTLA-4(-/-) T cells had a diverse and unbiased TCR repertoire, suggestive of a universal, Ag-independent mechanism of activation and expansion. These findings provide insight into the diverse mechanisms controlling T cell homeostasis.

Intrathoracic muscle flap transposition in the treatment of fibrocavernous tuberculosis

BACKGROUND AND OBJECTIVE

Conventionally, pulmonary resection with thoracoplasty is used to treat fibrocavernous complication of pulmonary tuberculosis. This operation is usually bloody, time-consuming with complicated postoperative course. To prevent massive blood loss and preserved pulmonary function, a more simplified operative procedure, cavernostomy combined intrathoracic muscle flap transposition was used and the outcome was evaluated in this study.

DESIGN

Retrospective review.

METHODOLOGY

Between December 1989 and June 1996, a total of ten patients with fibrocavernous pulmonary tuberculosis were managed using cavernostomy combined with intrathoracic muscle flap transposition. Five of them had concomitant aspergilloma within the cavity while three had multiple drug resistant pulmonary tuberculosis. The muscle flap was used to plombage the cavity and reinforce the closure of bronchopleural fistula after cavernostomy.

RESULTS

Six postoperative complications occurred in five patients, including reformation of cavity (2), bronchopleurocutaneous fistulae (3), and postoperative bleeding (1). The success or failure of intrathoracic muscle flap transposition on patients with fibrocavernous tuberculosis was significantly correlated with the size of the cavity (194.0+/-11.2 vs. 283.0+/-44.6 cm(3), P=0.016) and the number of bronchopleural fistulae (1.6+/-0.4 vs. 4.0+/-0.4, P=0.008). There was no operative death and in long term follow-up, there was no recurrence of hemoptysis or deterioration of pulmonary function in the successful group of patients.

CONCLUSIONS

Cavernostomy combined with intrathoracic muscle flap transposition can be used to treat well-selected fibrocavernous pulmonary tuberculosis patients, except on patients with large size cavity, multiple bronchopleural fistulae or multiple drug resistance tuberculosis.

The virus-specific and allospecific cytotoxic T-lymphocyte response to lymphocytic choriomeningitis virus is modified in a subpopulation of CD8(+) T cells coexpressing the inhibitory major histocompatibility complex class I receptor Ly49G2

The role of negatively signaling NK cell receptors of the Ly49 family on the specificity of the acute CD8(+) cytotoxic T-lymphocyte (CTL) response was investigated in lymphocytic choriomeningitis virus (LCMV)-infected C57BL/6 mice. Activated CD8(+) T cells coexpressing Ly49G2 expanded during LCMV infection, and T-cell receptor analyses by flow cytometry and CDR3 spectratyping revealed a unique polyclonal T-cell population in the Ly49G2(+) fraction. These cells lysed syngeneic targets infected with LCMV or coated with two of three LCMV immunodominant peptides examined. Transfection of these sensitive targets with H2D(d), a ligand for Ly49G2, inhibited lysis. This was reversed by antibody to Ly49G2, indicating effective negative signaling. LCMV characteristically induces an anti-H2(d) allospecific T-cell response that includes T-cell clones cross-reactive between allogeneic and LCMV-infected syngeneic targets. The CD8(+) Ly49G2(+) population mediated no allospecific killing, nor was any NK-like killing observed against YAC-1 cells. This study shows that CD8(+) Ly49G2(+) cells participate in the virus-induced CTL response but lyse a more restricted range of targets than the rest of the virus-induced CTL population.

Antioxidative effect of intestinal bacteria Bifidobacterium longum ATCC 15708 and Lactobacillus acidophilus ATCC 4356

The antioxidative effect of intact cells and intracellular cell-free extracts of intestinal lactic acid bacteria B. longum (ATCC 15708) and L. acidophilus (ATCC 4356) was investigated. Both intact cells and intracellular cell-free extracts of 10(9)cells of B. longum and L. acidophilus demonstrated antioxidative activity, inhibiting linoleic acid peroxidation by 28-48%. This indicated that these two strains demonstrated excellent antioxidative activity. B. longum and L. acidophilus also showed the ability to scavenge alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) free radical, scavenging 21-52%. The intact cells of these two intestinal bacteria demonstrated a high inhibitory effect on the cytotoxicity of 4-nitroquinoline-N-oxide (4NQO). Cytotoxicity of 4NQO was reduced by L. acidophilus by approximately half and by almost 90% by B. longum. Nevertheless, no inhibition of cytoxicity observed for intracellular cell-free extracts of 10(9) cells of B. longum and L. acidophilus. The effect of B. longum and L. acidophilus on inhibiting plasma lipid peroxidation was also evaluated. The results showed that both intestinal strains were able to protect plasma lipid from oxidation at different degrees. The inhibition rates on plasma lipid peroxidation ranged from 11 to 29% for 10(9) cells of B. longum and L. acidophilus. Generally speaking, B. longum demonstrated better antioxidative ability than L. acidophilus in this study.

Evolution of the CD8 T-cell repertoire during infections

CD8 T cells exist in a dynamic network whose repertoire remains static in the absence of infection but changes in the presence of foreign antigens. Individuals each have unique T-cell repertoires that continually evolve in the presence of antigen and of cross-reactive heterologous antigens, and homeostatic forces drive deletions in T-cell memory pools to accommodate the entry of new memory cells into a finite immune system.

Attrition of T cell memory: selective loss of LCMV epitope-specific memory CD8 T cells following infections with heterologous viruses

Using a variety of techniques, including limiting dilution assays (LDA), intracellular IFNgamma assays, and Db-IgG1 MHC dimer staining to measure viral peptide-specific T cell number and function, we show here that heterologous virus infections quantitatively delete and qualitatively alter the memory pool of T cells specific to a previously encountered virus. We also show that a prior history of a virus infection can alter the hierarchy of the immunodominant peptide response to a second virus and that virus infections selectively reactivate memory T cells with distinct specificities to earlier viruses. These results are consistent with a model for the immune system that accommodates memory T cell populations for multiple pathogens over the course of a lifetime.

Inhibition of lipid peroxidation by Lactobacillus acidophilus and Bifidobacterium longum

The inhibition of lipid peroxidation by Lactobacillus acidophilus and Bifidobacterium longum was investigated using two lipid model systems. All eight strains, including six strains of L. acidophilus and two strains of B. longum, demonstrated an inhibitory effect on linoleic acid peroxidation. The inhibitory rates on linoleic acid peroxidation ranged from 33 to 46% when 1 mL of intracellular cell-free extract was tested. In the second model system, the cell membrane of osteoblast was used as the source for biological lipid. The results indicated that all strains were able to protect biological lipids from oxidation. The inhibition rates on cell membrane lipid peroxidation ranged from 22 to 37%. The effect of L. acidophilus and B. longum on inhibition of fluorescent tissue pigment accumulation was also obtained for osteoblastic cells. The inhibition rates on fluorescent tissue pigment accumulation ranged from 20 to 39%. The antioxidative effect of each milliliter of intracellular cell-free extract of L. acidophilus and B. longum was equivalent to 104-172 ppm of butylated hydroxytoluene (BHT). These results indicated that all strains demonstrated high antioxidative activity. The scavenging ability of lipid peroxidation products, tert-butyl hydroperoxide and malondialdehyde, was also evaluated. The results showed that L. acidophilus and B. longum were not able to scavenge the tert-butyl hydroperoxide. Nevertheless, malondialdehyde was scavenged well by these strains.

Reactive oxygen species and lipid peroxidation product-scavenging ability of yogurt organisms

The antioxidative activity of the intracellular extracts of yogurt organisms was investigated. All 11 strains tested, including five strains of Streptococcus thermophilus and six strains of Lactobacillus delbrueckii ssp. bulgaricus, demonstrated an antioxidative effect on the inhibition of linoleic acid peroxidation. The antioxidative effect of intracellular extracts of 10(8) cells of yogurt organisms was equivalent to 25 to 96 ppm butylated hydroxytoluene, which indicated that all strains demonstrated excellent antioxidative activity. The scavenging of reactive oxygen species, hydroxyl radical, and hydrogen peroxide was studied for intracellular extracts of yogurt organisms. All strains showed reactive oxygen species-scavenging ability. Lactobacillus delbrueckii ssp. bulgaricus Lb demonstrated the highest hydroxyl radical-scavenging ability at 234 microM. Streptococcus thermophilus MC and 821 and L. delbrueckii ssp. bulgaricus 448 and 449 scavenged the most hydrogen peroxide at approximately 50 microM. The scavenging ability of lipid peroxidation products, t-butylhydroperoxide and malondialdehyde, was also evaluated. Results showed that the extracts were not able to scavenge the t-butylhydroperoxide. Nevertheless, malondialdehyde was scavenged well by most strains.

Identification of the sigma C-encoded gene of avian reovirus by nested PCR and restriction endonuclease analysis

A nested reverse transcription (RT)-polymerase chain reaction with subsequent restriction endonuclease analysis was developed for identification of the sigma C-encoded gene of avian reoviruses (ARV). PCR products derived from the sigma C-encoded gene of all tested ARVs resulted in a specific DNA band of 1023 bp, indicating that there were no apparent insertions or deletions in this region. Amplification with the nested primer pairs S1M-S1N and S1P-S1N generated 330 and 239 bp, respectively. PCR products amplified from the sigma C-encoded of all tested ARVs isolates were further confirmed by Southern blot hybridization and restriction endonuclease analysis. PCR amplified cDNA fragment (1023 bp) cleaved with Pst I generated two fragments of 565 and 458 bp. The amplified sigma C-encoded gene of ARV was subcloned into PQE 32 vector for further study of its antigenicity and immunogenicity. The sensitivity of RT-PCR was examined on nucleic acids from the ARV infected cell cultures. The detection limit was 10(0) to 10(-1) TCID50 of ARV in a ethidium bromide stained gel and could be increased further to 10(-1) to 10(-2) TCID50 of ARV by Southern blot hybridization using a digoxigenin-labeled cDNA probe. The sensitivity increased approximately 10(3) to 10(4) folds when the cDNA was reamplified with two sets of nested primers.

Comparison of two molecular techniques for the detection of avian reoviruses in formalin-fixed, paraffin-embedded chicken tissues

Reverse transcription (RT) in situ polymerase chain reaction (PCR) and in situ hybridization (ISH) techniques were used to detect the sigma c-encoded gene of avian reovirus (ARV) in chicken tissue sections. The advantage of using in situ methods is to make more rapid and accurate diagnosis of ARV infections. The sensitivity of these two techniques were compared. Of the two techniques, the RT in situ PCR test was found to be more sensitive than ISH and provided the rapid, sensitive, and specific detection of ARV infections.

Antioxidative ability of lactic acid bacteria

Nineteen strains of lactic acid bacteria were investigated for antioxidative activity. These includedLactobacillus acidophilus B, E, N1, 4356, LA-1, and Farr; Lactobacillus bulgaricus 12 278, 448, 449, Lb, 1006, and 11 842; Streptococcus thermophilus 821, MC, 573, 3641, and 19 987; and Bifidobacterium longum B6 and 15 708. Intracellular cell-free extract of all strains demonstrated antioxidative activity with inhibition rates of ascorbate autoxidation in the range of 7-12%. Antioxidative mechanisms including metal ion chelating ability, scavenge of reactive oxygen species, enzyme inhibition, and reducing activity of intracellular cell-free extract of lactic acid bacteria were studied. S. thermophilus 821 had the highest metal ion chelating ability for Fe(2+), and B. longum 15 708 showed the highest Cu(2+) chelating ability among the 19 strains tested. All strains demonstrated reactive oxygen species scavenging ability. L. acidophilus E showed the highest hydroxyl radical scavenging ability, and B. longum B6 had the best hydrogen peroxide scavenging ability. Reducing activity was also found in all strains. Most of the strains tested demonstrated excellent reducing activity. B. longum B6 showed the highest reducing activity among the 19 strains tested. In enzyme inhibition, superoxide dismutase activity was not found in these 19 strains, and the activity of superoxide dismutase was not induced when metal ion Mn(2+), Fe(2+), or Cu(2+)Zn(2+) was present.

Morphine tolerance in arthritic rats and serotonergic system

To understand whether chronic inflammation alters the development of morphine tolerance, the tail-flick test was used to evaluate the analgesic effect of morphine (75 mg tablet, s.c.) in the arthritic rats at the day 9-12 after the inoculation with Freund's adjuvant. Spinal cord monoamines and amino acid neurotransmitters were concomitantly measured. Chronic inflammation attenuated the antinociceptive effect of morphine as tolerance developed faster in the arthritic rats compared to the vehicle-treated controls. In addition, ratio of 5-hydroxyindole-3-acetic acid/5-hydroxytryptamine (5-HIAA/5-HT) increased in the lumbar spinal cord of arthritic rats without any change in the concentrations of norepinephrine, glutamate, aspartate or GABA. Interestingly, increased serotonin turnover in the spinal cord was observed in both control and arthritic rats 24 hours after morphine treatment. Overall, the results suggest a significant role of serotonin up-regulation in the spinal cord during chronic pain and the development of morphine tolerance.

Stability and diversity of T cell receptor repertoire usage during lymphocytic choriomeningitis virus infection of mice

Numerous studies have examined T cell receptor (TCR) usage of selected virus-specific T cell clones, yet little information is available regarding the stability and diversity of TCR repertoire usage during viral infections. Here, we analyzed the Vbeta8.1 TCR repertoire directly ex vivo by complementarity-determining region 3 (CDR3) length spectratyping throughout the acute lymphocytic choriomeningitis virus (LCMV) infection, into memory, and under conditions of T cell clonal exhaustion. The Vbeta8 population represented 30-35% of the LCMV-induced CD8(+) T cells and included T cells recognizing several LCMV-encoded peptides, allowing for a comprehensive study of a multiclonal T cell response against a complex antigen. Genetically identical mice generated remarkably different T cell responses, as reflected by different spectratypes and different TCR sequences in same sized spectratype bands; however, a conserved CDR3 motif was found within some same sized bands. This indicated that meaningful studies on the evolution of the T cell repertoire required longitudinal studies within individual mice. Such longitudinal studies with peripheral blood lymphocyte samples showed that (a) the virus-induced T cell repertoire changes little during the apoptosis period after clearance of the viral antigens; (b) the LCMV infection dramatically skews the host T cell repertoire in the memory state; and (c) continuous selection of the T cell repertoire occurs under conditions of persistent infections.

Differential surface accessibility of alpha(187-199) in the Torpedo acetylcholine receptor alpha subunits

We have probed the surface accessibility of residues alpha187 to alpha199 of the Torpedo acetylcholine receptor with monoclonal antibody 383C, which binds uniquely to these residues. However, 383C binds to only one of the two alpha subunits in the membrane-bound receptor, neither of the two subunits in carbamylcholine-desensitized receptor, and to both alpha subunits in Triton X-100 solubilized receptor. The kinetics of association and dissoci-ation of 383C with the peptide alpha(183-199) compared to those with the membrane-bound receptor suggest that all but a single hydrogen bond of affinity derives from contacts between this peptide and the monoclonal antibody paratope. Inhibition of 383C binding by alpha-bungarotoxin selectively directed to the alpha subunit correlated with the high-affinity d-tubocurarine binding site, along with a lack of inhibition by alpha-bungarotoxin directed to the alpha subunit correlated with the low-affinity d-tubocurarine binding site, suggests that the 383C epitope on the membrane-bound receptor resides on the alpha subunit associated with the high-affinity d-tubocurarine binding site. The results presented here suggest a structural basis for the differences between the two receptor acetylcholine binding sites.

The use of total quality improvement techniques to determine risk factors for back injuries in hospital workers

OBJECTIVE

To identify the risk factors for back injuries among hospital employees using quality-management techniques.

METHODS

Data from employee-health records were collected from 1993 to 1995 on a total of 100 back injuries. The data were reviewed retrospectively for risk factors using quality-management techniques.

RESULTS

We identified two major categories of risk factors: administrative and environmental. The five most common causes of back injuries were as follows: inadequate or lack of proper training in body mechanics, not enough help in lifting, the load being lifted was too heavy, poor condition of the floor surface (slippery or uneven), and the patient was unable to help. The Workers' Compensation costs for the 100 back injuries was in excess of $600,000.

CONCLUSION

Based on these findings, several preventive strategies are identified.

Management of lactose maldigestion by consuming milk containing lactobacilli

The influence of nonfermented milk containing L. acidophilus or L. bulgaricus on lactose utilization by lactose maldigesters was investigated. Nonfermented milks containing L. acidophilus or L. bulgaricus at 10(8) and 10(9) CFU/ml were prepared using 2% low-fat milk. Lactose maldigestion was monitored by measuring breath hydrogen at hourly intervals for 8 hr following consumption of 400 ml of each diet. Nonfermented milk containing L. acidophilus B at 10(8) CFU/ml were not effective in reducing breath hydrogen and symptoms. Nonfermented milk containing L. acidophilus B at 10(9) CFU/ml only slightly decreased breath hydrogen production; however, the symptoms were significantly improved. Nonfermented milks containing L. bulgaricus 449 at 10(8) and 10(9) CFU/ml were effective in reducing breath hydrogen and symptoms. The results for bulgaricus milk were all significant. In this study, L. acidophilus B and L. bulgaricus 449 were chosen because of their similar beta-galactosidase activity and bile sensitivity. L. acidophilus and L. bulgaricus are both thermophilic lactobacilli and an active transport (permease) system is found in both species for lactose transport. The major factor affecting in vivo lactose digestion in this study appears to be the bacterial cell wall/membrane structures. That the cell wall/membrane structures of L. acidophilus are different from those of L. bulgaricus can be indirectly proven by the results of sonication time for maximum beta-galactosidase activity measurement. The results of this study indicate that L. bulgaricus is usually a better choice than L. acidophilus for manufacturing nonfermented milks for lactose maldigesters.

Surgical results of 40 patients with malignant tracheobronchial lesions

The objective of this study was to evaluate the results of tracheobronchoplastyperformed on a variety of malignant diseases which involved the tracheobronchus. Between July 1988 and March 1996 tracheobronchial surgery was performed on 40 patients who had a variety of malignant diseases. The primary diseases were bronchogenic carcinoma (n=26), tracheobronchial tumour (n=5), thyroid cancer (n=6), and oesophageal cancer (n=3). Operative procedures that were performed on the tracheobronchus were sleeve lobectomy (n=22) or bilobectomies (n=5), sleeve pneumonectomy (n=3), sleeve resection of trachea (n=7) and bronchus (n=3). There was one postoperative death with a mortality rate of 2.5%. However, there were no significant postoperative complications apart from the one postoperative death; one patient developed a bronchopleural fistula and empyema. In lung cancer patients, the 2 year survival rate was 47.3%, and one (3.8%) local tumour recurrence. Four of five patients who had tracheobronchial tumours were alive and free from disease during 2-6 year follow-up period. One patient who had malignant fibrous histiocytoma died of brain metastasis 6 months after the operation. Among six patients whose thyroid cancer involved the trachea, one patient survived for 7 years, the other five patients were still alive and free from disease 2-5 years after the operation. Of the three patients whose oesophageal carcinoma involved the tracheobronchus, there was one operative death and the others died of tumour recurrence 1 and 2 years, respectively. We suggest that tracheobronchoplasty is a safe procedure with low morbidity and mortality rates in carefully selected patients with malignant diseases.