Endocytosis blocks the vesicular secretion of exosome marker proteins

Exosomes are secreted vesicles of ~30 to 150 nm diameter that play important roles in human health and disease. To better understand how cells release these vesicles, we examined the biogenesis of the most highly enriched human exosome marker proteins, the exosomal tetraspanins CD81, CD9, and CD63. We show here that endocytosis inhibits their vesicular secretion and, in the case of CD9 and CD81, triggers their destruction. Furthermore, we show that syntenin, a previously described exosome biogenesis factor, drives the vesicular secretion of CD63 by blocking CD63 endocytosis and that other endocytosis inhibitors also induce the plasma membrane accumulation and vesicular secretion of CD63. Finally, we show that CD63 is an expression-dependent inhibitor of endocytosis that triggers the vesicular secretion of lysosomal proteins and the clathrin adaptor AP-2 mu2. These results suggest that the vesicular secretion of exosome marker proteins in exosome-sized vesicles occurs primarily by an endocytosis-independent pathway.

Syntenin and CD63 Promote Exosome Biogenesis from the Plasma Membrane by Blocking Cargo Endocytosis

Exosomes are small extracellular vesicles important in health and disease. Syntenin is thought to drive the endosomal biogenesis of CD63 exosomes by recruiting Alix and the ESCRT machinery to endosome-localized CD63. We find instead that syntenin blocks CD63 endocytosis, allowing CD63 to accumulate at the plasma membrane, thereby increasing its direct budding from the plasma membrane. Consistent with this model, we show that specific and general inhibitors of endocytosis induce the exosomal secretion of CD63 and that endocytosis signals inhibit the vesicular secretion of exosome cargo proteins. Furthermore, we show that CD63 is itself a competitive inhibitor of AP-2-mediated endocytosis, driving the plasma membrane accumulation and exosomal secretion of itself and other lysosome membrane proteins. Our results support the hypothesis that highly-enriched exosome cargo proteins bud primarily from the plasma membrane, that endocytosis inhibits their loading into exosomes, and that syntenin and CD63 regulate the loading of lysosomal proteins into exosomes by an Alix-independent modulation of endocytosis.

[Diagnosis and treatment strategies of 56 cases of middle ear myoclonus]

Objective: To analyze the clinical characteristics and treatment of middle ear myoclonus. Methods: Fifty-six cases of middle ear myoclonus were enrolled in Shandong Provincial ENT Hospital, Shandong University from September 2019 to August 2021, including 23 males and 33 females. The age ranged from 6 to 75 years, with a median age of 35 years; Forty-seven cases were unilateral tinnitus, nine cases were bilateral tinnitus. The time of tinnitus ranged from 20 days to 8 years. The voice characteristics, inducing factors, nature (frequency) of tinnitus, tympanic membrane conditions during tinnitus, audiological related tests, including long-term acoustic tympanogram, stapedius acoustic reflex, pure tone auditory threshold, short increment sensitivity test, alternate binaural loudness balance test, loudness discomfort threshold, vestibular function examination, facial electromyography, and imaging examination were recorded. Oral carbamazepine and/or surgical treatment were used. The patients were followed up for 6-24 months and the tinnitus changes were observed. Results: Tinnitus was diverse, including stepping on snow liking sound, rhythmic drumming, white noise, and so on. The inducing factors included external sound, body position change, touching the skin around the face and ears, speaking, chewing and blinking, etc. Forty-four cases were induced by single factor and 9 cases were induced by two or more factors. There was no definite inducing factor in 1 case. One patient had tinnitus with epilepsy. One case of traumatic facial paralysis after facial nerve decompression could induce tinnitus on the affected side when the auricle moved. Tympanic membrane flutter with the same frequency as tinnitus was found in 12 cases by otoscopy, and the waveform with the same frequency as tinnitus was found by long-term tympanogram examination. There were 7 patients with no tympanic membrane activity by otoscopy, the 7 cases also with the same frequency of tinnitus by long-term tympanogram examination, but the change rate of the waveform was faster than that of the patients with tympanic membrane flutter. All patients with tinnitus had no change in hearing. One case of tinnitus complicated with epilepsy (a 6-year-old child) was treated with antiepileptic drug (topiramate) and tinnitus subsided. One case suffered from tinnitus after facial nerve decompression for traumatic facial paralysis was not given special treatment. Fifty-four cases were treated with oral drug (carbamazepine), of which 10 cases were completely controlled and 23 cases were relieved; 21 cases were invalid. Among the 21 patients with no effect of carbamazepine treatment, 8 patients were treated by surgery, 7 patients had no tinnitus after surgery, 1 patient received three times of operation, and the third operation was followed up for 6 months, no tinnitus occurred again. The other 13 cases refused the surgical treatment due to personal reasons. Conclusions: Middle ear myoclonus tinnitus and the inducing factors manifestate diversity. Oral carbamazepine and other sedative drugs are effective for some patients, and surgical treatment is feasible for those who are ineffective for medication.

The D614G mutation redirects SARS-CoV-2 spike to lysosomes and suppresses deleterious traits of the furin cleavage site insertion mutation

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) egress occurs by lysosomal exocytosis. We show that the Spike D614G mutation enhances Spike trafficking to lysosomes, drives Spike-mediated reprogramming of lysosomes, and reduces cell surface Spike expression by ~3-fold. D614G is not a human-specific adaptation. Rather, it is an adaptation to the earlier furin cleavage site insertion (FCSI) mutation that occurred at the genesis of SARS-CoV-2. While advantageous to the virus, furin cleavage of spike has deleterious effects on spike structure and function, inhibiting its trafficking to lysosomes and impairing its infectivity by the transmembrane serine protease 2(TMPRSS2)-independent, endolysosomal pathway. D614G restores spike trafficking to lysosomes and enhances the earliest events in SARS-CoV-2 infectivity, while spike mutations that restore SARS-CoV-2's TMPRSS2-independent infectivity restore spike's trafficking to lysosomes. Together, these and other results show that D614G is an intragenic suppressor of deleterious traits linked to the FCSI and lend additional support to the endolysosomal model of SARS-CoV-2 egress and entry.

A shared, stochastic pathway mediates exosome protein budding along plasma and endosome membranes

Exosomes are small extracellular vesicles of ∼30 to 150 nm that are secreted by all cells, abundant in all biofluids, and play important roles in health and disease. However, details about the mechanism of exosome biogenesis are unclear. Here, we carried out a cargo-based analysis of exosome cargo protein biogenesis in which we identified the most highly enriched exosomal cargo proteins and then followed their biogenesis, trafficking, and exosomal secretion to test different hypotheses for how cells make exosomes. We show that exosome cargo proteins bud from cells (i) in exosome-sized vesicles regardless of whether they are localized to plasma or endosome membranes, (ii) ∼5-fold more efficiently when localized to the plasma membrane, (iii) ∼5-fold less efficiently when targeted to the endosome membrane, (iv) by a stochastic process that leads to ∼100-fold differences in their abundance from one exosome to another, and (v) independently of small GTPase Rab27a, the ESCRT complex–associated protein Alix, or the cargo protein CD63. Taken together, our results demonstrate that cells use a shared, stochastic mechanism to bud exosome cargoes along the spectrum of plasma and endosome membranes and far more efficiently from the plasma membrane than the endosome. Our observations also indicate that the pronounced variation in content between different exosome-sized vesicles is an inevitable consequence of a stochastic mechanism of small vesicle biogenesis, that the origin membrane of exosome-sized extracellular vesicles simply cannot be determined, and that most of what we currently know about exosomes has likely come from studies of plasma membrane-derived vesicles.

Degron tagging of BleoR and other antibiotic-resistance genes selects for higher expression of linked transgenes and improved exosome engineering

Five antibiotic resistance (AR) genes have been used to select for transgenic eukaryotic cell lines, with the BleoR, PuroR, HygR, NeoR, and BsdR cassettes conferring resistance to zeocin, puromycin, hygromycin, geneticin/G418, and blasticidin, respectively. We recently demonstrated that each AR gene establishes a distinct threshold of transgene expression below which no cell can survive, with BleoR selecting for the highest level of transgene expression, nearly ∼10-fold higher than in cells selected using the NeoR or BsdR markers. Here, we tested the hypothesis that there may be an inverse proportionality between AR protein function and the expression of linked, transgene-encoded, recombinant proteins. Specifically, we fused each AR protein to proteasome-targeting degron tags, used these to select for antibiotic-resistant cell lines, and then measured the expression of the linked, recombinant protein, mCherry, as a proxy marker of transgene expression. In each case, degron-tagged AR proteins selected for higher mCherry expression than their cognate WT AR proteins. ER50BleoR selected for the highest level of mCherry expression, greater than twofold higher than BleoR or any other AR gene. Interestingly, use of ER50BleoR as the selectable marker translated to an even higher, 3.5-fold increase in the exosomal loading of the exosomal cargo protein, CD63/Y235A. Although a putative CD63-binding peptide, CP05, has been used to decorate exosome membranes in a technology known as "exosome painting," we show here that CP05 binds equally well to CD63-/- cells, WT 293F cells, and CD63-overexpressing cells, indicating that CP05 may bind membranes nonspecifically. These results are of high significance for cell engineering and especially for exosome engineering.

The D614G Mutation Enhances the Lysosomal Trafficking of SARS-CoV-2 Spike

The spike D614G mutation increases SARS-CoV-2 infectivity, viral load, and transmission but the molecular mechanism underlying these effects remains unclear. We report here that spike is trafficked to lysosomes and that the D614G mutation enhances the lysosomal sorting of spike and the lysosomal accumulation of spike-positive punctae in SARS-CoV-2-infected cells. Spike trafficking to lysosomes is an endocytosis-independent, V-ATPase-dependent process, and spike-containing lysosomes drive lysosome clustering but display poor lysotracker labeling and reduced uptake of endocytosed materials. These results are consistent with a lysosomal pathway of coronavirus biogenesis and raise the possibility that a common mechanism may underly the D614G mutation’s effects on spike protein trafficking in infected cells and the accelerated entry of SARS-CoV-2 into uninfected cells.

Gut microbiome is more stable in males than in females during the development of colorectal cancer

AIMS

Gut microbial alterations have great potential to predict the development of colorectal cancer (CRC); however, how gut microbes respond to the development of CRC in males and females at the community level is unknown. We aim to investigate the differences of gut microbiota between the male and female.

METHODS AND RESULTS

We reanalysed the dataset in a published project from a sex perspective at the community level by characterizing the gut microbiome in patients (including males and females) from three clinical groups representative of the stages of CRC development: healthy, adenoma, and carcinoma. The results indicated that the microbial α-diversity showed no significant difference in the male gut but had decreased significantly in the female gut with the development of CRC. In males, a significant difference in the microbial β-diversity was only observed between the healthy and carcinoma subgroups. However, significant community deviations were detected with the development of CRC in females. The microbial community assembly processes changed from deterministic to stochastic in males, whereas they became increasingly deterministic in females with the development of CRC. Moreover microbial co-occurrence associations tended to be more complicated in males; rare species were enriched in the co-occurrence network of the male gut, whereas key species loss was observed in the co-occurrence network of the female gut.

CONCLUSIONS

The microbial communities in the male gut were more stable than those in the female gut, and microbial community assembly in the gut was sex dependent with the development of CRC. Our study suggests that sexual dimorphism needs to be considered to better predict the risk of CRC based on microbial shifts.

SIGNIFICANCE AND IMPACT OF THE STUDY

To the best of our knowledge, this is the first report showing how gut microbes respond to the development of CRC in males and females at the community scale.

RNA methyltransferase BCDIN3D is crucial for female fertility and miRNA and mRNA profiles in Drosophila ovaries

RNA methyltransferases post-transcriptionally add methyl groups to RNAs, which can regulate their fates and functions. Human BCDIN3D (Bicoid interacting 3 domain containing RNA methyltransferase) has been reported to specifically methylate the 5′-monophosphates of pre-miR-145 and cytoplasmic tRNA^His. Methylation of the 5′-monophosphate of pre-miR-145 blocks its cleavage by the miRNA generating enzyme Dicer, preventing generation of miR-145. Elevated expression of BCDIN3D has been associated with poor prognosis in breast cancer. However, the biological functions of BCDIN3D and its orthologs remain unknown. Here we studied the biological and molecular functions of CG1239, a Drosophila ortholog of BCDIN3D. We found that ovary-specific knockdown of Drosophila BCDIN3D causes female sterility. High-throughput sequencing revealed that miRNA and mRNA profiles are dysregulated in BCDIN3D knockdown ovaries. Pathway analysis showed that many of the dysregulated genes are involved in metabolic processes, ribonucleoprotein complex regulation, and translational control. Our results reveal BCDIN3D’s biological role in female fertility and its molecular role in defining miRNA and mRNA profiles in ovaries.

Aldolase B-Mediated Fructose Metabolism Drives Metabolic Reprogramming of Colon Cancer Liver Metastasis

Cancer metastasis accounts for the majority of cancer-related deaths and remains a clinical challenge. Metastatic cancer cells generally resemble cells of the primary cancer, but they may be influenced by the milieu of the organs they colonize. Here, we show that colorectal cancer cells undergo metabolic reprogramming after they metastasize and colonize the liver, a key metabolic organ. In particular, via GATA6, metastatic cells in the liver upregulate the enzyme aldolase B (ALDOB), which enhances fructose metabolism and provides fuel for major pathways of central carbon metabolism during tumor cell proliferation. Targeting ALDOB or reducing dietary fructose significantly reduces liver metastatic growth but has little effect on the primary tumor. Our findings suggest that metastatic cells can take advantage of reprogrammed metabolism in their new microenvironment, especially in a metabolically active organ such as the liver. Manipulation of involved pathways may affect the course of metastatic growth.

Dietary Intake is Positively Associated with Cognitive Function of a Chinese Older Adults Sample

OBJECTIVE

The relationship between cognitive function and dietary intake in older adults was under-studied in China. This study examined this relationship in a Chinese sample while controlling for the effects of sleep quality and socio demographic confounders.

METHODS

The sample consisted of 340 Chinese older adults (age > 60) who were randomly selected from Wuhan city in central China. Cognitive function was assessed by the Mini-mental State Examination [MMSE], sleep quality by the Pittsburgh Sleep Quality Index [PSQI], and dietary intake by frequencies of intake of meat products, fruits, fish/seafood/aquatic products, nuts and mushroom/algae over the past year. First, confirmatory factor analysis (CFA) was conducted to evaluate the measurement properties of cognitive function, dietary intake, and sleep quality. Second, structural equation modeling (SEM) was conducted to examine the relations of cognitive function, dietary intake, and sleep quality.

RESULTS

Dietary intake was found to be positively related to cognitive function. Older age, lower education status, monthly income, and living alone or without a spouse were significantly associated with poorer cognitive function. SES status had an indirect effect on cognitive function via dietary intake.

CONCLUSION

Dietary intake may be critical to maintain normal cognitive function of older adults in China.

Isotropic-nematic transition for hard rods on a three-dimensional cubic lattice

Using grand-canonical Monte Carlo (GCMC) simulations, we investigate the isotropic-nematic phase transition for hard rods of size L×1×1 on a three-dimensional cubic lattice. We observe such a transition for L≥6. For L=6, the nematic state has a negative order parameter, reflecting the co-occurrence of two dominating orientations. For L≥7, the nematic state has a positive order parameter, corresponding to the dominance of one orientation. We investigate rod lengths up to L=25 and find evidence for a very weakly first-order isotropic-nematic transition, while we cannot completely rule out a second-order transition. It was not possible to detect a density jump at the transition, despite using large systems containing several 10^{5} particles. The probability density distributions P(Q) from the GCMC simulations near the transition are very broad, pointing to strong fluctuations. Our results complement earlier results on the demixing (pseudonematic) transition for an equivalent system in two dimensions, which is presumably of Ising type and occurs for L≥7. We compare our results to lattice fundamental measure theory (FMT) and find that FMT strongly overestimates nematic order and consequently predicts a strong first-order transition. The rod packing fraction of the nematic coexisting states, however, agree reasonably well between FMT and GCMC.

A miR-34a-Numb Feedforward Loop Triggered by Inflammation Regulates Asymmetric Stem Cell Division in Intestine and Colon Cancer

Emerging evidence suggests that microRNAs can initiate asymmetric division, but whether microRNA and protein cell fate determinants coordinate with each other remains unclear. Here, we show that miR-34a directly suppresses Numb in early-stage colon cancer stem cells (CCSCs), forming an incoherent feedforward loop (IFFL) targeting Notch to separate stem and non-stem cell fates robustly. Perturbation of the IFFL leads to a new intermediate cell population with plastic and ambiguous identity. Lgr5+ mouse intestinal/colon stem cells (ISCs) predominantly undergo symmetric division but turn on asymmetric division to curb the number of ISCs when proinflammatory response causes excessive proliferation. Deletion of miR-34a inhibits asymmetric division and exacerbates Lgr5+ ISC proliferation under such stress. Collectively, our data indicate that microRNA and protein cell fate determinants coordinate to enhance robustness of cell fate decision, and they provide a safeguard mechanism against stem cell proliferation induced by inflammation or oncogenic mutation.

[Ultrahigh-frequency hearing thresholds in middleaged and elderly healthy adults]

Objective:To investigate the ultrahigh-frequency(UHF) hearing thresholds in middle-aged and elderly healthy subjects .Method: Healthy subjects(age range: 50-69 ) were divided into two groups,i.e.50-59 year-old group and >59-69 year-old group.Each subject was tested with both conventional-frequency(0.25,0.50,1.00,2.00,4.00,6.00 and 8.00 kHz) and ultrahigh-frequency(9.0,10.0,11.5,12.5,14.0,16.0,18.0,and 20.0 kHz) audiometry.UHF was performed twice to evaluate the reliability.The best hearings among 20-29 aged healthy adults were considered as normal controls.Results:Seventy five middle-aged and elderly subjects were included,with 39 subjects(78 ears) being 50-59 years old and 36(72 ears) being >59-69 year-old.Eighteen subjects(36 ears) aging from 20 to 29 were considers as controls.For the conventional-frequency,the hearing thresholds in middle-aged and elderly people were significantly higher than those in young people(all P<0.05),especially at ≥4 kHz.Although the conventional-frequency thresholds in >59-69 year-old group were higher than those in 50-59 year-old,the difference was significant just at 4 kHz(P<0.05).The UHF thresholds in middle-aged and elderly people were significantly higher than those in young people(all P<0.05).The thresholds at 9,10,11.5 and 12.5 kHz in >59-69 year-old people were significantly increased than those in 50-59 year-old counterparts(all P<0.05).Hearing threshold at ≥12.5 kHz couldn't be detected in some subjects in middle-aged and elderly group.The response rate at UHF in >59-69 year-old people were just higher than that in 50-59 year-old counterparts (P>0.05),and none responded at 18 and 20 kHz.The standard deviations(SDs) for <14 kHz in 50-59 year-old and for <11.5 kHz in >59-69 year-old subjects,were both higher than that in 20-29 year old counterparts.Above 6 kHz,the SDs in 50-59 year-old subjects were significantly higher than those in >59-69 year-old subjects(all P<0.05).Conclusion:For middle-aged and elderly people,the hearing loss may occur from 4 kHz.Hearing thresholds at UHF were increased with age,and it might be used as an early indicator for age-induced hearing loss.However,the UHF sensitivity decreased as the frequency increased beyond 14 kHz.

A long non-coding RNA targets microRNA miR-34a to regulate colon cancer stem cell asymmetric division

The roles of long non-coding RNAs (lncRNAs) in regulating cancer and stem cells are being increasingly appreciated. Its diverse mechanisms provide the regulatory network with a bigger repertoire to increase complexity. Here we report a novel LncRNA, Lnc34a, that is enriched in colon cancer stem cells (CCSCs) and initiates asymmetric division by directly targeting the microRNA miR-34a to cause its spatial imbalance. Lnc34a recruits Dnmt3a via PHB2 and HDAC1 to methylate and deacetylate the miR-34a promoter simultaneously, hence epigenetically silencing miR-34a expression independent of its upstream regulator, p53. Lnc34a levels affect CCSC self-renewal and colorectal cancer (CRC) growth in xenograft models. Lnc34a is upregulated in late-stage CRCs, contributing to epigenetic miR-34a silencing and CRC proliferation. The fact that lncRNA targets microRNA highlights the regulatory complexity of non-coding RNAs (ncRNAs), which occupy the bulk of the genome.

DOI:http://dx.doi.org/10.7554/eLife.14620.001

Tumors are made of millions of cells that are not all the same. A type of cancer cell known as cancer stem cells (or CSCs for short) are often better at dividing to produce new cells and moving to new sites in the body than other types of cancer cell. Very small molecules called micro ribonucleic acids (or microRNAs for short) can influence how CSCs grow and divide by regulating the activity of specific genes. For example, a microRNA molecule called miR-34a suppresses the activity of several genes – which slows the growth of various tumors, including lung and bowel cancers. This miR-34a is often missing from some types of cells in advanced tumors.

Genes encode the instructions to produce RNAs, and Wang, Bu et al. wanted to find out what stops miR-34a being produced in certain bowel cancer cells. The experiments revealed a new, very long RNA molecule – named long non-coding RNA 34 (or Lnc34a) – that binds to the gene that encodes miR-34a. Lnc34a recruits proteins that modify the gene and switch off the production of miR-34a.

Furthermore, microscopy experiments revealed that when colon cancer cells divide, Lnc34a is distributed unevenly so that it blocks the production of miR-34a in one daughter cell but not the other. Lastly, Wang, Bu et al. confirmed that Lnc34a is found in higher levels in CSCs than in other cancer cells, which helps them to grow and divide more rapidly. Future experiments will try to find out what controls the production of Lnc34a and search for drugs that can block this process in cancer cells.

DOI:http://dx.doi.org/10.7554/eLife.14620.002

Targeted drug delivery to circulating tumor cells via platelet membrane-functionalized particles

Circulating tumor cells (CTCs) are responsible for metastases in distant organs via hematogenous dissemination. Fundamental studies in the past decade have suggested that neutralization of CTCs in circulation could represent an effective strategy to prevent metastasis. Current paradigms of targeted drug delivery into a solid tumor largely fall into two main categories: unique cancer markers (e.g. overexpression of surface receptors) and tumor-specific microenvironment (e.g. low pH, hypoxia, etc.). While relying on a surface receptor to target CTCs can be greatly challenged by cancer heterogeneity, targeting of tumor microenvironments has the advantage of recognizing a broader spectrum of cancer cells regardless of genetic differences or tumor types. The blood circulation, however, where CTCs transit through, lacks the same tumor microenvironment as that found in a solid tumor. In this study, a unique "microenvironment" was confirmed upon introduction of cancer cells of different types into circulation where activated platelets and fibrin were physically associated with blood-borne cancer cells. Inspired by this observation, synthetic silica particles were functionalized with activated platelet membrane along with surface conjugation of tumor-specific apoptosis-inducing ligand cytokine, TRAIL. Biomimetic synthetic particles incorporated into CTC-associated micro-thrombi in lung vasculature and dramatically decreased lung metastases in a mouse breast cancer metastasis model. Our results demonstrate a "Trojan Horse" strategy of neutralizing CTCs to attenuate metastasis.

Cortical glutamate levels decrease in a non-human primate model of dopamine deficiency

While Parkinson's disease is the result of dopaminergic dysfunction of the nigrostriatal system, the clinical manifestations of Parkinson's disease are brought about by alterations in multiple neural components, including cortical areas. We examined how 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration affected extracellular cortical glutamate levels by comparing glutamate levels in normal and MPTP-lesioned nonhuman primates (Macaca mulatta). Extracellular glutamate levels were measured using glutamate microelectrode biosensors. Unilateral MPTP-administration rendered the animals with hemiparkinsonian symptoms, including dopaminergic deficiencies in the substantia nigra and the premotor and motor cortices, and with statistically significant decreases in basal glutamate levels in the primary motor cortex on the side ipsilateral to the MPTP-lesion. These results suggest that the functional changes of the glutamatergic system, especially in the motor cortex, in models of Parkinson's disease could provide important insights into the mechanisms of this disease.

Intraputamenal Infusion of Exogenous Neurturin Protein Restores Motor and Dopaminergic Function in the Globus Pallidus of MPTP-Lesioned Rhesus Monkeys

The neurorestorative effects of exogenous neurturin (NTN) delivered directly into the putamen via multiport catheters were studied in 10 MPTP-lesioned rhesus monkeys expressing stable parkinsonism. The parkinsonian animals were blindly assigned to receive coded solutions containing either vehicle (n = 5) or NTN (n = 5, 30 μg/day). Both solutions were coinfused with heparin using convection-enhanced delivery for 3 months. The NTN recipients showed a significant and sustained behavioral improvement in their parkinsonian features during the treatment period, an effect not seen in the vehicle-treated animals. At study termination, locomotor activity levels were increased by 50% in the NTN versus vehicle recipients. Also, DOPAC levels were significantly increased by 150% ipsilateral (right) to NTN infusion in the globus pallidus, while HVA levels were elevated bilaterally in the NTN-treated animals by 10% on the left and 67% on the right hemisphere. No significant changes in DA function were seen in the putamen. Volumetric analysis of putamenal NTN labeling showed between-subject variation, with tissue distribution ranging from 214 to 744 mm3, approximately equivalent to 27–93% of area coverage. Our results support the concept that intraparenchymal delivery of NTN protein may be effective for the treatment of PD. More studies are needed to determine strategies that would enhance tissue distribution of exogenous NTN protein, which could contribute to optimize its trophic effects in the parkinsonian brain.

Intraputamenal infusion of exogenous neurturin protein restores motor and dopaminergic function in the globus pallidus of MPTP-lesioned rhesus monkeys

The neurorestorative effects of exogenous neurturin (NTN) delivered directly into the putamen via multiport catheters were studied in 10 MPTP-lesioned rhesus monkeys expressing stable parkinsonism. The parkinsonian animals were blindly assigned to receive coded solutions containing either vehicle (n = 5) or NTN (n = 5, 30 microg/day). Both solutions were coinfused with heparin using convection-enhanced delivery for 3 months. The NTN recipients showed a significant and sustained behavioral improvement in their parkinsonian features during the treatment period, an effect not seen in the vehicle-treated animals. At study termination, locomotor activity levels were increased by 50% in the NTN versus vehicle recipients. Also, DOPAC levels were significantly increased by 150% ipsilateral (right) to NTN infusion in the globus pallidus, while HVA levels were elevated bilaterally in the NTN-treated animals by 10% on the left and 67% on the right hemisphere. No significant changes in DA function were seen in the putamen. Volumetric analysis of putamenal NTN labeling showed between-subject variation, with tissue distribution ranging from 214 to 744 mm3, approximately equivalent to 27-93% of area coverage. Our results support the concept that intraparenchymal delivery of NTN protein may be effective for the treatment of PD. More studies are needed to determine strategies that would enhance tissue distribution of exogenous NTN protein, which could contribute to optimize its trophic effects in the parkinsonian brain.

Evidence for a distinct group of nestin-immunoreactive neurons within the basal forebrain of adult rats

Nestin is an intermediate filament protein serving as a marker for neuroprogenitor and stem cells. Here we report that a cluster of previously unrecognized nestin immunoreactive (nestin-ir) neurons was located in the medial septum-diagonal band of Broca (MS-DBB) of the basal forebrain in adult rats. Nestin-ir neurons were exclusively located in the MS-DBB and intermingled with choline acetyltransferase-ir (ChAT-ir), parvalbumin-ir (PV-ir), or nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase reactive (NADPHd-reactive) neurons. However, there was no colocalization between nestin-ir and PV-ir in single neurons in MS-DBB; only about 35% of nestin-ir neurons were ChAT-ir, and 8%-12% of nestin-ir neurons were NADPHd-reactive. Morphologically, nestin-ir neurons showed a larger size of somata than that of ChAT-ir or PV-ir neurons and the distribution of nestin-ir neurons spread across the rostro-caudal extent of the MS-DBB. Moreover, retrograde tracing revealed that a significant portion of these nestin-ir neurons projected to the thalamus and hippocampus. These results, for the first time, provide strong evidence that there exists a cluster of previously unrecognized nestin-ir neurons in MS-DBB of the basal forebrain in adult rats and that these nestin-ir neurons are distinguishable from ChAT-ir, PV-ir, and NADPHd-reactive neurons.

[The clinical features of multiple-trauma patients APACHE II score system]

The clinical features of 76 multiple-trauma patients in the intensive care unit were observed with acute physiology and chronic health evaluation (APACHE II) system. The results showed that the mean value of APACHE II scores in 76 patients was 18.4; the mean duration of staying at the ICU was 91.5 hours. Six patients died in the ICU (7.9%), 13 patients were complicated with MODS (17.1%), and 10 patients developed ARDS (13.2%). As APAHCE II scores increased, the duration of the patient staying at the ICU lengthened and the mortality went up.

[Investigation on skin retrograde degeneration after tissue expansion]

OBJECTIVE

To study the effects of tissue expansion on tissue damage and retrograde degeneration.

METHODS

9 cases of conventional intermittent tissue expansion (CITE) and 9 cases of continuous pressure-controlled tissue expansion (CPTE) were chosen for the study. In creating of the expanded flaps, tissue samples were taken for histopathology, molecular biology and transmission electron microscope (TEM) examinations.

RESULTS

Capillary bleeding, elastic and reticular fiber proliferation, arteriole thrombosis, fibroblast apoptosis and collagenolysis were observed after expansion. Retrograde degeneration was obvious in CITE group and acute lesion was obvious in CPTE group.

CONCLUSION

Expansion stimulation induces tissue damage and retrograde degeneration, which indicates that the time for conventional intermittent expansion should be shortened and too fast continuous expansion is harmful.

Abnormal migration phenotype of mitogen-activated protein kinase-activated protein kinase 2-/- neutrophils in Zigmond chambers containing formyl-methionyl-leucyl-phenylalanine gradients

Time-lapsed video microscopy and confocal imaging were used to study the migration of wild-type (WT) and mitogen-activated protein kinase-activated protein kinase 2 (MK2-/-) mouse neutrophils in Zigmond chambers containing fMLP gradients. Confocal images of polarized WT neutrophils showed an intracellular gradient of phospho-MK2 from the anterior to the posterior region of the neutrophils. Compared with WT neutrophils, MK2-/- neutrophils showed a partial loss of directionality but higher migration speed. Immunoblotting experiments showed a lower protein level of p38 mitogen-activated protein kinase and a loss of fMLP-induced extracellular signal-related kinase phosphorylation in MK2-/- neutrophils. These results suggest that MK2 plays an important role in the regulation of neutrophil migration and may also affect other signaling molecules.

Leukocyte-specific gene 1 protein (LSP1) is involved in chemokine KC-activated cytoskeletal reorganization in murine neutrophils in vitro

Leukocyte-specific gene 1 protein (LSP1) is a cytoskeletal-associated protein of leukocytes that in vitro cross-links F-actin into extensively branched bundles of mixed polarity. In this study, we examined chemotaxis and superoxide production in neutrophils prepared from wild-type (WT) and Lsp1 knockout mice. Compared to WT neutrophils, Lsp1-/- neutrophils showed impairment in both migration speed and chemotaxis direction during chemokine KC-directed chemotaxis. When examined by confocal microscopy, chemotaxing Lsp1-/- neutrophils showed abnormal morphologies. They had discontinuous primary actin-rich cortexes and large membrane protrusions. When stimulated by phorbol 12-myristate 13-acetate (PMA), Lsp1-/- peritoneal neutrophils produce more superoxide than WT. The data presented suggest that LSP1 plays important roles in the regulation of neutrophil morphology, motility, and superoxide production.

[Survey on the growth of interpupillary distance of Chinese children aged 5 to 17 years]

OBJECTIVE

To investigate the interpupillary distance (IPD) of Chinese children for stipulating the sizes for children spectacle frames.

METHOD

The IPD of 10171 children aged 5 to 17 years old was measured with a caliper in four cities.

RESULTS

The IPD was positively correlated with the age increase from 5 to 17 years. The IPD in males was larger than that in females. The differences of IPD between males and females in the age groups of 5 to 9 and 10 to 15 years were statistically significant (F = 400.97, P < 0.01).

CONCLUSIONS

There are two peak periods of the growth of IPD in Chinese children at 5 to 9 and 10 to 15 years. The IPD in males reaches adult level at age 15 and in females at age 13. The differences of the IPD between male and female and among 4 cities have no practical meaning in stipulating the sizes of children spectacle frames.

A mouse model of galactose-induced cataracts

Galactokinase (GK; EC 2.7.1.6) is the first enzyme in the metabolism of galactose. In humans, GK deficiency results in congenital cataracts due to an accumulation of galactitol within the lens. In an attempt to make a galactosemic animal model, we cloned the mouse GK gene (Glk1) and disrupted it by gene targeting. As expected, galactose was very poorly metabolized in GK-deficient mice. In addition, both galactose and galactitol accumulated in tissues of GK-deficient mice. Surprisingly, the GK-deficient animals did not form cataracts even when fed a high galactose diet. However, the introduction of a human aldose reductase transgene into a GK-deficient background resulted in cataract formation within the first postnatal day. This mouse represents the first mouse model for congenital galactosemic cataract.

P47(phox)-deficient NADPH oxidase defect in neutrophils of diabetic mouse strains, C57BL/6J-m db/db and db/+

Deficiencies in neutrophil NADPH oxidase proteins have been demonstrated in humans with chronic granulomatous disease. However, no spontaneous mutation in murine NADPH oxidase has been reported. In this study we report that neutrophils from the diabetic mouse strains, C57BL/6J-m heterozygous lean (lepr(db/+)) and homozygous obese (lepr(db/db)) mice produced no superoxide on stimulation. An absence of intact p47(phox) but not other oxidase proteins was observed in both mouse strains through the use of immunoblotting. Molecular analysis by reverse transcriptase-polymerase chain reaction identified three abnormal p47phox mRNA transcripts. Sequencing of genomic DNA of p47(phox) revealed a point mutation at the -2 position of exon 8, which is consistent with aberrant splicing of the p47(phox) transcript. These results indicate that the C57BL/6J-m db/db and db/+ mice are the first spontaneously derived murine model of NADPH oxidase deficiency involving a p47(phox) mutation.

[A case of fetal valproate syndrome with intractable wheezing due to submucosal tumor below the vocal cord]

A full-term baby was born to an epileptic mother treated with two anti-epileptic drugs, sodium valproate and phenobarbital, throughout the pregnancy. She was given no information about the risk of teratogenesis of these drugs. At birth the patient was hypotonic and had clinical features specific for the fetal valproate syndrome. After a viral infection at three months of age, he had intractable and persistent wheezing. Suspecting the presence of congenital respiratory tract abnormality, we performed tracheobronchoscopy, which revealed a relatively big submucosal tumor on the left trachial wall below the vocal cord. Dyspnea and wheezing were remarkably improved by tracheolaryngotomy, but he died suddenly and unexplainedly at seven months of age.

Construction and application of MCBL plate for facilitation of chromosome recombination in fungi

A medium with camphor and benomyl MCBL plate was designed and constructed based on the proposed mechanism that d-camphor could induce the fusion of nuclear membrane while benomyl could induce the nondisjunctional recombination of chromosome in fungi. This so-called co-induction plate consisted of 0.1% d-camphor (W/V) and 0.5 microgram/L benomyl contained in Czapek's minimal medium. The precautions to be taken in the construction procedure of this plate was described in detail. One typical example of intergeneric fusion-cross, Aspergillus niger x Trichoderma reesei, was investigated, comparing the ratios of genotypes and phenotypes of fusant progenies produced by the co-induction of MCBL plate and by the step-by-step induction with camphor and benomyl separately. The results showed that the heterodiploid state was extremely transient and the recombinant haploid was hardly obtained when induced by the routine step-by-step method, whereas the ratios of apparent diplodization and nondisjunctional recombinant haplodization among all types of varied segregates on MCBL plate were greatly improved, compared with those on the routine plates containing single reagents, which indicated that the transient heterodiploid could be grasped and transformed further into nondisjunctional recombinant haploid when co-induced on the MCBL plate. The age of regenerated mycelium to be induced was found to have a dominant influence on the co-induction effects of MCBL plate. The mechanism of co-induction by MCBL plate and its promising applications were discussed.

MPTP-Induced pallidal lesions in rhesus monkeys

Dopamine neurons in the substantia nigra of the midbrain are the primary neuronal population affected by 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine (MPTP) toxicity, which produces the pathological and behavioral features of Parkinson's disease in nonhuman primates and man. We have identified another injury site in magnetic resonance imaging (MRI) brain scans in 13 of 37 rhesus monkeys taken 10-12 months after administration of this neurotoxin via the right carotid artery. Focal lesions, ranging in volume from 6.75 to 60 mm3 in the rostral globus pallidus region, were seen on the right side of the brain in these 13 animals in addition to the midbrain effects. While no significant differences were seen between globus pallidus lesioned and nonlesioned animals in the severity of MPTP-induced parkinsonian symptoms, the response to levodopa was muted in pallidal-lesioned animals. To confirm the role of neurotoxicity in producing the lesions, brain scans from an additional 12 monkeys were evaluated during the acute period following exposure to either MPTP (n = 6) or saline (n = 6). Focal lesions in the rostral globus pallidus were seen as early as 2-4 h following a carotid artery infusion in two of six MPTP recipients, but no evidence of injury was seen in saline recipients. The globus pallidus includes important components of the neural circuitry regulating motor functions. The present results indicate that in addition to midbrain dopamine neurons, a focal region of the rostral globus pallidus is selectively vulnerable to MPTP toxicity.

[Study on the effect of human herpesvirus 6 on replication of Epstein-Barr virus]

OBJECTIVE

To examine the effect of human herpesvirus 6(HHV-6) on the replication of Epstein-Barr virus (EBV) in cell lines.

METHODS

Both EBV-infected Raji cells and EBV-transformed lymphoblastoid cell lines (LCL) were infected with HHV-6. Immunofluoresence assay (IFA) with monoclonal antibodies (MAb) against HHV-6 was applied to confirm the infection of HHV-6 in the two cell lines. Expression of EBV antigen was examined by IFA using human anti-EBV serum.

RESULTS

Following HHV-6 infection, cytopathic effects (CPE) were observed in Raji cells but not in LCL. HHV-6 were detected in both cell lines by IFA with anti-HHV-6 MAb, but not in controls. EBV antigens were detected by IFA with human serum against EBV in both HHV-6 infected cell lines.

CONCLUSION

Data in this study suggest that HHV-6 promotes the expression of EBV antigen and may contribute to the pathogenesis of nasopharyngeal carcinoma in cooperation with EBV.

[The intergeneric compatibility of heredity and expression for cellulase genomes between Aspergillus niger and Trichoderma reesei]

By using the developed display techniques of cellulase isozymes and the RAPD-PCR analysis guided by a deduced universal sequence of cellulase genes, the polymorphisms of genomic DNA fingerprints and cellulase isozymes were compared among three typical stable recombinants (3a, 3b, A7-1) and their two parents (Aspergillus niger AMS11, Trichoderma reesei QM9414) in order to provide the molecular evidence of gene recombination, to demonstrate the compatibility of heredity and expression of intergeneric genomes, and to assay on the molecular fundamentals of hybridization dominance. The results showed that in these recombinant strains the recombinantal fingerprints of genomic DNA could be stablly hereditary and the expression of recombinantal CMCase (carboxymethylcellulase) and beta GLase (beta-glucosidase) could be compatibly enhanced. The diversity of molecular fundamentals of cellulase hybridization dominance were (1) the compatible co-existence and enhanced expression of some hereditary beta GLase-coding genes from two parents in recombinant 3b; and (2) the compatibly enhancement of expression between the hereditary genes encoding beta GLase and CMCase from two parents, resulting in the dramatic increase of proteins of corresponding isozymes in recombinants 3a and A7-1. Based on these, a proposal model for the double synergism on cellulase activity in vitro and on its biosynthesis in vivo mediated by beta GLase was suggested. A practical method for assaying on the molecular fundamentals and the stability of hybridization dominance of recombinants was thereby established in this study.

The role of p38 MAP kinase in TGF-beta1-induced signal transduction in human neutrophils

Transforming growth factor-beta 1 (TGF-beta 1) is the strongest chemoattractant yet described for human neutrophils. It activates neither phospholipase C nor phospholipase D. It does not induce rises in intracellular calcium, degranulation, or superoxide production. The signaling pathways utilized by TGF-beta 1 are largely unknown. This report demonstrates that TGF-beta 1 activates p38 MAP kinase. The kinase inhibitor SB203580 blocks the chemotactic responses as well as actin polymerization induced by TGF-beta 1. Potential cellular targets of the p38 MAP kinase pathway which could mediate these function are discussed.

Hybridization dominance of kinetics in recombinant ATH-1376 obtained via protoplast fusion between Aspergillus niger and Trichoderma reesei

Comparisons of the kinetics of mycelium growth, cellulase biosynthesis, and the degradation of filter paper to accumulate reducing-sugar by the filtrates of cultures were carried out among the recombinant strain ATH-1376 and its two parents, Aspergillus niger AMS11 and Trichoderma reesei QM9414. The results showed that both the specific mycelium growth rate and the cellulase biosynthesis rate of the recombinant were dramatically dominant over those of the two parents. In addition, the negative correlation between the specific mycelium growth rate and the cellulase biosynthesis rate of the recombinant ATH-1376 was much lower than those of its parents. In terms of the amount of reducing-sugar accumulated from the hydrolysis of filter paper by culture filtrates, there were great differences among the three different treatments, i.e., fermentation filtrate of single parental strain, mixture of the fermentation filtrates from two parental strains with different ratios (v:v), and filtrate from the mixed culture of the two parental strains. Out of these, the second approach, particularly with the ratio of 1:1, was best for the accumulation of reducing sugar. Within various tested periods of enzymic hydrolysis, the amounts of reducing-sugar produced by the recombinant were 1.19 to 2.26 times as much as the maximum amounts produced in parallel by the mixture of filtrates (1:1) from separate fermentations of the two parental strains. These results suggested that constructing the engineered strains with hybridization dominance of these two typical genera of far-heredity could be effective to overcome the great deficiencies of routine mixculture, single-strain fermentation, or double fed-batch fermentations.

[Scalp expansion in treatment of scalp defect with skull exposure]

We repaired the scalp defect and skull exposure with scalp expansion. The technique consisted of two stages. First, expander was implaned an then N. S injected to its enough volume. The size of the expander was estimated by the formula that 1 cm2 needs 4 ml expansive volume. The incision was made at normal skin. Second flap was transferred. The expander was removed and the external skull which was necrotic severed. There were five patient with eight flaps at all, followed up for 6 months to 1 year. The hair grew. The results were satisfactory. This method not only treated the disease, but also avoided alopecia.

High expression and activation of MAP kinase-activated protein kinase 2 in cardiac muscle cells

Recently, three mammalian mitogen-activated protein (MAP) kinases, ERK, SAPK/JNK, and p38/HOG-1 have been identified, each with apparently unique signal transduction pathways. The p38 MAP kinase mediates an intracellular stress-activated signaling pathway by regulating down-stream molecules, such as MAP kinase-activated protein (MAPKAP) kinase 2. To study the tissue specificity of MAPKAP kinase 2, mRNA blots containing multiple human tissues were hybridized with a specific oligonucleotide probe corresponding to human MAPKAP kinase 2. The Northern blot analysis revealed that two mRNA species of MAPKAP kinase 2, with sizes of 4.8 and 3.3 kb, were expressed in high levels in both human heart and skeletal muscle tissues. To better understand how MAPKAP kinase 2 is regulated in myocardium, cultured rat cardiac myoblast (H9c2) cells were stimulated with heat shock, H2O2-induced oxidative stress, or phorbol ester (PMA). Enzymatic activity of cellular MAPKAP kinase 2 in the cell lysates was evaluated using an in vitro kinase assay. Exposure of H9c2 cells to heat shock or oxidative stress induced a transient increase of cellular MAPKAP kinase 2 activity, which reached its peak level within 5 min. In contrast, stimulation of H9c2 cells with PMA, a potential myocardial hypertrophic factor, induced a sustained increase of cellular MAPKAP kinase 2 activity that was detectable for over 1 h. In addition, in vitro protein phosphorylation analysis with recombinant MAPKAP kinase 2 showed that small heat shock protein (hsp25) served as a major substrate molecule for the kinase in H9c2 cells and the protein phosphorylation of cellular hsp25 was stimulated by H2O2-induced oxidative stress or PMA treatment in intact H9c2 cells. Moreover, exposure of H9c2 cells to H2O2-induced oxidative stress or PMA rapidly activated cellular p38 MAP kinase as detected by the induced protein phosphorylation of the kinase. Taken together, these results strongly suggest that MAPKAP kinase 2 may be involved in stress-activated signal transduction in myocardium.

LSP1 is the major substrate for mitogen-activated protein kinase-activated protein kinase 2 in human neutrophils

In intact cells, mitogen-activated protein kinase-activated protein (MAPKAP) kinase 2 is rapidly activated by various cytokines, stresses, and chemotactic factors. The small heat shock protein p27 has been shown to be a substrate for MAPKAP kinase 2. Recently, we identified a novel substrate, designated p60, for MAPKAP kinase 2 in human neutrophils (Zu, Y.-L., Ai, Y., Gilchrist, A., Labadia, M. E., Sha'afi, R. I., and Huang, C.-K. (1996) Blood 87, 5287-5296). To further understand the signaling pathway of MAPKAP kinase 2, we have purified p60 from a heat-treated neutrophil lysate by DEAE-cellulose chromatography and SDS-polyacrylamide gel electrophoresis. Microsequencing of five peptides derived from purified p60 indicates that p60 is lymphocyte-specific protein 1 (LSP1). Furthermore antibodies specific for human and mouse LSP1 react with human and mouse p60. The sequence of human LSP1 indicates two serine residues at positions 204 and 252 as potential phosphorylation sites. The amino acid sequences surrounding these two sites are in agreement with the consensus sequence (Xaa-Xaa-Hyd-Xaa-Arg-Xaa-Xaa-Ser-Xaa-Xaa) for phosphorylation by MAPKAP kinase 2. Both serine residues in human LSP1 and the corresponding conserved serine residues in mouse LSP1 are in the basic C-terminal F-actin binding domain. Various fusion proteins of wild type and truncated mouse LSP1 with glutathione S-transferase were tested for their capacity to be phosphorylated by MAPKAP kinase 2. The results indicate that LSP1 is a substrate for MAPKAP kinase 2 in vitro and that the phosphorylation sites are located in the basic C-terminal domain of LSP1. Because both the small heat shock proteins and LSP1 are F-actin binding proteins, these results suggest a role for MAPKAP kinase 2 in the regulation of cytoskeletal structure or function.

Fine structure of the human galactokinase GALK1 gene

Defects in the human GALK1 gene result in galactokinase deficiency and cataract formation. We have isolated this gene and established its structural organization. The gene contains 8 exons and spans approximately 7.3 kb of genomic DNA. The GALK1 promoter was localized and found to have many features in common with other housekeeping genes, including high GC content, several copies of the binding site for the Sp1 transcription factor, and the absence of TATA-box and CCAAT-box motifs typically present in eukaryotic Pol II promoters. Analysis by 5'-RACE PCR indicates that the GALK1 mRNA is heterogeneous at the 5' terminus, with transcription sites occurring at many locations between 21 and 61 bp upstream of the ATG start site of the coding region. In vitro translation experiments of the GALK1 cDNA indicate that the protein is cytosolic and not associated with the endoplasmic reticulum membrane.

[Endoscopic control during facelifting]

The endoscopic techniques were just recently applied to aesthetic surgery. The paper reports 22 cases of video endoscopic facelift that have been performed since April 1994. The operative results were satisfactory. Clinical experience with forehead plasty, resection of corrugator and procerus muscle and other cosmetic procedures using endoscopic technique is presented.

Activation of MAP kinase-activated protein kinase 2 in human neutrophils after phorbol ester or fMLP peptide stimulation

In response to extracellular stimulation, one of the earliest events in human neutrophils is protein phosphorylation, which mediates signal transduction and leads to the regulation of cellular functions. Mitogen-activated protein (MAP) kinases are rapidly activated by a variety of mitogens, cytokines, and stresses. The activated MAP kinases in turn regulate their substrate molecules by phosphorylation. MAP kinase-activated protein (MAPKAP) kinase 2, a Ser/Thr kinase, has been shown to be phosphorylated by p38 MAP kinase both in vivo and in vitro. Phosphorylation of the Thr-334 site of MAPKAP kinase 2 results in a conformational change with subsequent activation of the enzyme. To better define the role of MAPKAP kinase 2 in the activation of human neutrophils, its enzymatic activity was measured after stimulation by either a phorbol ester (phorbol myristate acetate [PMA]), a potent protein kinase C activator, or the tripeptide fMLP, which is a chemotactic factor. The in vitro kinase assays indicate that both PMA and fMLP stimulated a transient increase in the enzymatic activity of cellular MAPKAP kinase 2. The induced kinase activation was concentration-dependent and reached a maximum at 5 minutes for PMA and 1 minute for fMLP. To identify potential substrate molecules for MAPKAP kinase 2, a highly active kinase mutant was generated by mutating the MAP kinase phosphorylation site in the C-terminal region. The replacement of threonine 334 with alanine resulted in a marked augmentation of catalytic activity. Analysis of in vitro protein phosphorylation in the presence of the active kinase indicates that a 60-kD cytosolic protein (p60) was markedly phosphorylated and served as the major substrate for MAPKAP kinase 2 in human neutrophils. Based on the MAPKAP kinase 2 phosphorylation site of Hsp27, a competitive inhibitory peptide was synthesized. This competitive inhibitory peptide specifically inhibited MAPKAP kinase 2 enzymatic activity, as well as the in vitro and in vivo kinase-induced p60 phosphorylation. To assess the contribution of MAPKAP kinase 2 in neutrophil function, the oxidative burst response after manipulation of endogenous kinase activity was measured. Intracellular delivery of the competitive inhibitory peptide into human neutrophils reduced both PMA- and fMLP-stimulated superoxide anion production. Thus, the results strongly suggest that MAPKAP kinase 2 is involved in the activation of human neutrophils.

Research on soft-tissue expander permeability to metronidazole and procaine

This in vitro study was designed to determine if in fact silicone expanders are readily permeable to metronidazole and procaine. The expanders were filled with 0.2% metronidazole or 2% procaine through the filler valves and then immersed wholly in normal saline. At several intervals over 120 hours, a certain amount of the surrounding saline was sampled and the drug levels subsequently determined. In this study, the silicone expanders were indeed readily permeable to the drugs, as measured with an ultraviolet spectrophotometer. A consistent diffusion curve was demonstrated. The rate of diffusion of a drug is inversely proportional to its molecular weight; i.e., the smaller the given drug's molecular weight, the greater is its ability to permeate an expander. In view of this, in the course of expansion, 0.2% metronidazole could be used in clinical expansion instead of normal saline, and a certain amount of antibiotic would diffuse out of the expander to prevent and control the infection.

[The application of expanded delto-pectoral flaps in the faciocervical region]

The delto-pectoral flap has been used to repair burned scar in the faciocervical region for some years. However, its limited size restricts its application. Furthermore, direct transfer of the flap may result in a swelling and inexpressive face and the donor site needs skin grafting. To avoid the above disadvantages, we have tried pre-expansion of the flap. In this article, the authors report the experiences in the application of the method to eighteen cases, including the surgical procedure, the applied anatomy, and typical cases as well. Also included in the article are the comparison between various therapies to the burned scar of the face, the key points for successful pre-expansion of the delto-pectoral flap, accurately maintaining the desired position. The method has been proved to have many advantages and can be widely applied.