Purification, characterization and partial amino acid sequencing of a 70 kD inhibitor protein of Na+,K+-ATPase from goat testis cytosol

A protein isolated from goat testis cytosol is found to inhibit Na+,K+-ATPase from rat brain microsomes. The inhibitor has been purified by ammonium sulphate precipitation followed by hydroxyapatite column chromatography. The purified fraction appears as a single polypeptide band on 10% SDS-PAGE of approximate molecular mass of 70 kDa. The concentration at which 50% inhibition (I50) occurs is in the nanomolar range. The inhibitor seems to bind Na+,K+-ATPase reversibly at ATP binding site in a competitive manner with ATP, but away from ouabain binding site. It does not affect p-nitrophenyl-phosphatase activity. The inhibitor is found to inhibit the phosphorylation step of the Na+,K+-ATPase. The enhancement of tryptophan fluorescence and changes in CD pattern suggest conformational changes of Na+,K+-ATPase on binding to the inhibitor. Amino acid sequence of the trypsinised fragments show some homology with aldehyde reductase.

Do the Chinese somatize depression? A cross-cultural study

BACKGROUND

A large literature argues for the Chinese--whether in mainland China or elsewhere--being highly likely to express depression somatically, leading to predictable detection and diagnostic difficulties. If true, detection might be assisted if a set of somatic proxies of depression were identified, and this was the principal initial objective in mounting this study.

METHODS

We studied two sets of depressed outpatients, one of Malaysian Chinese and the other of Australian Caucasians, matched by age and sex. We identified the prime symptom nominated by them when they first sought assistance, and required them to complete an inventory of both somatic and cognitive symptoms, and rank the three items they judged as most capturing their distress.

RESULTS

The Chinese were distinctly more likely to nominate a somatic symptom as their presenting complaint (60% vs 13%), while the Australian subjects were more likely to nominate depressed mood, cognitive and anxiety items. Responses to the inventory established that the Chinese did score somewhat higher on a somatic set of items, but differed far more distinctly in being less likely to affirm cognitive items of depression, resulting in significantly lower total inventory scores. Variation across the contrast samples in acknowledging the presence of symptoms did not relate simply to the prevalences of those symptoms.

CONCLUSIONS

Our failure to identify a culture-specific somatic factor as a proxy of depression, together with establishing a high rate of somatic and related items (e. g. insomnia) in both samples, may largely reflect the phenomenon of 'corporization', whereby depressed patients irrespective of culture are more likely to experience and report in response to a 'somatosensory amplification' influence.

Climate-driven range expansion and morphological evolution in a marine gastropod

Little is known about the phenotypic consequences of global climate change, despite the excellent Pleistocene fossil record of many taxa. We used morphological measurements from extant and Pleistocene populations of a marine gastropod (Acanthinucella spirata) in conjunction with mitochondrial DNA sequence variation from living populations to determine how populations responded phenotypically to Pleistocene climatic changes. Northern populations show little sequence variation as compared to southern populations, a pattern consistent with a recent northward range expansion. These recently recolonized northern populations also contain shell morphologies that are absent in extant southern populations and throughout the Pleistocene fossil record. Thus, contrary to traditional expectations that morphological evolution should occur largely within Pleistocene refugia, our data show that geographical range shifts in response to climatic change can lead to significant morphological evolution.

Depression and smoking: examining correlates in a subset of depressed patients

OBJECTIVE

The objective of this study was to examine for associations between depression and cigarette smoking.

METHOD

A sample of 92 depressed smokers was compared with a control sample of depressed non-smokers, matched for age, gender and diagnostic variables. Comparisons were made across a range of demographic, depression, family history, developmental factors, anxiety and personality style variables, as well as use of alcohol and illicit drugs.

RESULTS

We failed to find any difference between smokers and non-smokers in history or severity of depression. Cigarette smokers were distinguished principally by greater exposure to aversive experiences in childhood, disordered personality function, greater use of illicit drugs, anxiolytics and alcohol. Logistic regression identified dysfunctional personality 'domains', physical violence in childhood, long-term anxiolytic use and illicit drug use as the most significant predictor set.

CONCLUSIONS

Results favour a model of cigarette smoking and depression as linked by shared early deprivational variables, rather than cigarette smoking causing depression or the converse.

Effects of sampling standardization on estimates of Phanerozoic marine diversification

Global diversity curves reflect more than just the number of taxa that have existed through time: they also mirror variation in the nature of the fossil record and the way the record is reported. These sampling effects are best quantified by assembling and analyzing large numbers of locality-specific biotic inventories. Here, we introduce a new database of this kind for the Phanerozoic fossil record of marine invertebrates. We apply four substantially distinct analytical methods that estimate taxonomic diversity by quantifying and correcting for variation through time in the number and nature of inventories. Variation introduced by the use of two dramatically different counting protocols also is explored. We present sampling-standardized diversity estimates for two long intervals that sum to 300 Myr (Middle Ordovician-Carboniferous; Late Jurassic-Paleogene). Our new curves differ considerably from traditional, synoptic curves. For example, some of them imply unexpectedly low late Cretaceous and early Tertiary diversity levels. However, such factors as the current emphasis in the database on North America and Europe still obscure our view of the global history of marine biodiversity. These limitations will be addressed as the database and methods are refined.

Hansch analysis of antimalarial cyclic peroxy ketals with physicochemical and electrotopological parameters

Hansch analysis of some antimalarial cyclic peroxy ketals (IV) having structural variations at the para substituted phenyl ring and an alicyclic ring of different size reveals that electronic and steric parameters of the phenyl ring substituents are important for explaining the variation in the activity while hydrophobicity parameter is of little significance. Electron withdrawing substituents with higher MR (molar refractivity) or V(W) (van der Waals volume) are preferred for the activity. Use of structural descriptors suggests that presence of a seven membered alicyclic ring attached to the peroxy bridge containing ring is conducive to the activity. Application of electrotopological state atom index (ETSAI) suggests a pharmacophore containing the peroxy bridge. This is corroborated by earlier observation on importance of oxygen atoms of the peroxy linkage of artemisinin for antimalarial activity. Although incorporation of ETSAI into Hansch model does not improve the relations, the electronic parameter sigma is found to be significantly correlated with it.

Double blind, randomised controlled clinical trial of hypo-osmolar oral rehydration salt solution in dehydrating acute diarrhoea in severely malnourished (marasmic) children

AIMS

To compare the clinical efficacy of hypo-osmolar oral rehydration salt (ORS) solution (224 mmol/l) and standard ORS solution (311 mmol/l) in severely malnourished (marasmic) children having less than 60% Harvard standard weight for age with dehydrating acute watery diarrhoea.

METHODS

In a double blind, randomised, controlled trial, 64 children aged 6-48 months were randomly assigned standard (n = 32) or hypo-osmolar ORS (n = 32).

RESULTS

Stool output (52.3 v 96.6 g/kg/day), duration of diarrhoea (41.5 v 66.4 hours), intake of ORS (111.5 v 168.9 ml/kg/day), and fluid intake (214.6 v 278.3 ml/kg/day) were significantly less in the hypo-osmolar group than in the standard ORS group. Percentage of weight gain on recovery in the hypo-osmolar group was also significantly less (4.3 v 5.4% of admission weight) than in the standard ORS group. A total of 29 (91%) children in the standard ORS group and 32 (100%) children in the hypo-osmolar group recovered within five days of initiation of therapy. Mean serum sodium and potassium concentrations on recovery were within the normal range in both groups.

CONCLUSION

Our findings suggest that hypo-osmolar ORS has beneficial effects on the clinical course of dehydrating acute watery diarrhoea in severely malnourished (marasmic) children. Furthermore, children did not become hyponatraemic after receiving hypo-osmolar ORS.

Chitosan-DNA nanoparticles as gene carriers: synthesis, characterization and transfection efficiency

Chitosan-DNA nanoparticles were prepared using a complex coacervation process. The important parameters for the nanoparticle synthesis were investigated, including the concentrations of DNA, chitosan and sodium sulfate, temperature of the solutions, pH of the buffer, and molecular weights of chitosan and DNA. At an amino group to phosphate group ratio (N/P ratio) between 3 and 8 and a chitosan concentration of 100 microg/ml, the size of particles was optimized to approximately 100--250 nm with a narrow distribution, with a composition of 35.6 and 64.4% by weight for DNA and chitosan, respectively. The surface charge of these particles was slightly positive with a zeta potential of +12 to +18 mV at pH lower than 6.0, and became nearly neutral at pH 7.2. The chitosan-DNA nanoparticles could partially protect the encapsulated plasmid DNA from nuclease degradation as shown by electrophoretic mobility analysis. The transfection efficiency of chitosan-DNA nanoparticles was cell-type dependent. Typically, it was three to four orders of magnitude, in relative light units, higher than background level in HEK293 cells, and two to ten times lower than that achieved by LipofectAMINE-DNA complexes. The presence of 10% fetal bovine serum did not interfere with their transfection ability. Chloroquine could be co-encapsulated in the nanoparticles at 5.2%, but with negligible enhancement effect despite the fact that chitosan only showed limited buffering capacity compared with PEI. The present study also developed three different schemes to conjugate transferrin or KNOB protein to the nanoparticle surface. The transferrin conjugation only yielded a maximum of four-fold increase in their transfection efficiency in HEK293 cells and HeLa cells, whereas KNOB conjugated nanoparticles could improve gene expression level in HeLa cells by 130-fold. Conjugation of PEG on the nanoparticles allowed lyophilization without aggregation, and without loss of bioactivity for at least 1 month in storage. The clearance of the PEGylated nanoparticles in mice following intravenous administration was slower than unmodified nanoparticles at 15 min, and with higher depositions in kidney and liver. However, no difference was observed at the 1-h time point.

Assessing the comparative effectiveness of antidepressant therapies: a prospective clinical practice study

BACKGROUND

Although efficacy studies suggest equal potency among antidepressant treatments, their effectiveness in clinical practice appears more variable, particularly in that the newer antidepressants may be less effective in either more severe depression or the melancholic subtype of depression. We pursue some factors that may impact the effectiveness of antidepressant treatments in a clinical sample.

METHOD

A sample of 182 patients with DSM-IV major depressive disorder was assessed at baseline and 12 months later to establish treatments provided, identify patients who had recovered from the index episode, and quantify likely treatment determinants. Four systems for distinguishing patients with melancholic and non-melancholic depression were examined to assess for differential effects of the antidepressant strategies across those subtypes.

RESULTS

Multimodal therapy (commonly, psychotherapy combined with an antidepressant drug) and patients' frequent attribution of recovery to spontaneous improvement made for difficulty in disentangling recovery determinants. After excluding a spontaneous improvement component, electroconvulsive therapy (ECT) and the irreversible monoamine oxidase inhibitors (MAOIs) appeared to be the most effective therapies across the sample, while the reversible inhibitor of monoamine oxidase-A (RIMA) appeared to be the least effective. The distinct gradient of suggested effectiveness of various strategies appeared to be contributed to principally by the varied effectiveness of alternate treatments across the melancholic subtype, whereby ECT, tricyclic antidepressants, and MAOIs were the most effective, and the selective serotonin reuptake inhibitors (SSRIs), RIMAs, and antipsychotic drugs were much less effective. For the nonmelancholic disorders, the effectiveness of SSRIs appeared to be comparable with that of older antidepressants.

CONCLUSION

Although most patients received a physical treatment, they commonly judged psychotherapy and spontaneous improvement to be influential in their recovery. Reasons for such attributions are worthy of clarifying studies. Despite patients' concerns about the side effects and stigma of ECT as well as the side effects associated with the older antidepressants, these therapies were rated as more helpful by patients-and were more strongly associated with recovery-than the newer antidepressant drugs. Such overall results are compatible with an earlier study undertaken by us involving an independent sample and retrospective data. The overall gradient is clarified by studying depressive subtypes, allowing an important conclusion. Although the newer and older antidepressant drugs may be of similar effectiveness in nonmelancholic depression, the newer agents appear comparatively inferior for the treatment of melancholia, findings that have clinical implications and perhaps inform us about the pathogenesis of melancholia.

Antibiotic prescribing knowledge of National Health Service general dental practitioners in England and Scotland

The inappropriate use of antibiotics has contributed to the worldwide problem of antimicrobial resistance. Information on the knowledge, understanding and training of dental practitioners in the use of antibiotics in clinical practice is scarce. This study assessed the level of knowledge of general dental practitioners and the need for educational initiatives. An anonymous postal questionnaire was sent to National Health Service dental practitioners working in 10 Health Authorities in England (1544) and four Health Boards in Scotland (672). Each correct answer to the questionnaire was given a score of one mark; there were 84 questions. The scores for each section of the questionnaire were compared. Responses were received from 1338 (60.4%) of practitioners, of whom 22.1% had attended postgraduate courses in the previous 2 years on antibiotic prescribing. Practitioners who had attended courses had a significantly greater knowledge of antibiotic use (P < 0.05) than those who had not. There was no significant difference in knowledge between all age groups under 60 years of age. There were significant differences in knowledge between dentists practising in English Health Authorities and Scottish Health Boards (P < 0.01). Knowledge was good for clinical signs that are indicators for prescribing antibiotics and for a number of non-clinical factors, e.g. patient expectation. Knowledge of therapeutic prescribing for commonly presenting clinical conditions and prophylactic prescribing for medically compromised patients, however, was generally poor. This study has shown that an urgent review of dental undergraduate and postgraduate education in antibiotic prescribing is required. Provision of prescribing guidelines may improve knowledge and encourage the appropriate use of antibiotics in clinical dental practice.

QSAR of antineoplastics IV: Hansch analysis of N-(7-indolyl)benzenesulfonamides against KB human nasopharynx carcinoma, colon 38 murine adenocarcinoma and P388 murine leukemia cell lines

Hansch analysis of recently reported antitumor activities of novel N-(7-indolyl)benzenesulfonamide derivatives against KB human nasopharynx carcinoma, colon 38 murine adenocarcinoma and P388 murine leukemia cell lines reveals that the pattern of receptor interactions in human KB cells differs from that in murine (colon 38 and P388 leukemia) cells. The latter two activities are autocorrelated and show similar receptor specificity. It seems that two binding sites, one interacting with the indole fragment and another with phenyl fragment of the indolylbenzenesulfonamide compounds, are present on the murine cell receptors (colon 38 and P388 leukemia) while only the latter binding site is active on the human KB cell receptors. For the activity against KB cells, a para-methyl or paramethoxy substituent on the phenyl ring of benzenesulfonamide moiety greatly enhances the activity. For the other two activities, a 3-chloro or 3-cyano substituent on indole nucleus enhances activities, while presence of bulkier meta or para substituent on the phenyl ring decreases activities. Presence of an ortho substituent on the phenyl ring appears to be detrimental for all the three activities. Equations generated by both QSAR and QAAR studies are quite robust as evidenced from cross-validation by 'leave-one-out' technique.

QSAR of antineoplastics V: Exploration of receptor interaction sites of antitumor N-(7-indolyl)benzenesulfonamides targeting GI phase using electrotopological state atom index

Quantitative structure activity relationship (QSAR) study of antiproliferative activities of N-(7-indolyl)benzenesulfonamides with electrotopological state atom (ETSA) index corroborates the conclusions of the previously reported Hansch analysis that the structural requirements for interactions with receptors of human KB nasopharynx cell line are different from that for murine colon 38 and P388 leukemia cell lines. The study suggests that both phenyl ring and indole moiety are the important receptor interaction sites present on the ligands for the murine cell lines, while the latter site does not appear to play significant role in case of human KB cell carcinoma.

Culture condition-dependent senescence-like growth arrest and immortalization in rodent embryo cells

Culture Condition-Dependent Senescence-Like Growth Arrest and Immortalization in Rodent Embryo Cells. We investigated the telomerase activity, telomere length, and replicative life span of cells from human embryos and rodent embryos (mouse, rat and Syrian hamster). We used two culture conditions for rodent embryo cells whereby the cells were plated at a density of 2 x 10(5) into a 25-cm(2) flask and subcultured every 3 days or every 10 days. We found that nearly 100% of the cultures of rodent embryo cells become immortal when they are subcultured using the 10-day culture protocol. These rodent embryo cells retain telomerase activity and long telomeres (19-50 kb) in the long-term cultures, whereas human embryo cells rapidly deplete telomerase activity associated with significant shortening of telomeres, and then they senesce. In contrast to the results from 10-day cultures, we found that some mouse cell cultures and most Syrian hamster cell cultures arrest cell growth after 13 and 29 population doublings, respectively, while retaining substantial levels of telomerase activity and experiencing no significant loss of telomeres when the cells were subcultured using the 3-day culture protocol. This growth arrest is phenotypically indistinguishable from cellular senescence. The present results suggest that in rodent cells the onset of senescence-like arrest can be activated without repression of telomerase, and that this activation pathway can be bypassed easily under certain culture conditions, such as the 10-day culture protocol.

Hypoxia relieves X-ray-induced delayed effects in normal human embryo cells

We studied the effect of hypoxia on X-ray-induced delayed effects in normal human embryo cells to elucidate the role of oxidative stress in the susceptibility of cells to induction of genetic instability by radiation. We examined X-ray-induced delayed cell death, giant cell formation, and chromosome aberrations under normally oxygenated (20%) and hypoxic (2%) conditions at 28-38 population doublings postirradiation. The results revealed that hypoxia reduced the X-ray-induced delayed effects, suggesting that radiation enhances cellular oxidative stress, which plays a significant role in determining the susceptibility of irradiated cells to genetic instability. The present study emphasizes the biological significance of epigenetic effects, such as oxygen tension, as well as direct DNA damage in the induction of genetic instability by radiation.

Invariant size-frequency distributions along a latitudinal gradient in marine bivalves

In the most extensive analysis of body size in marine invertebrates to date, we show that the size-frequency distributions of northeastern Pacific bivalves at the provincial level are surprisingly invariant in modal and median size as well as size range, despite a 4-fold change in species richness from the tropics to the Arctic. The modal sizes and shapes of these size-frequency distributions are consistent with the predictions of an energetic model previously applied to terrestrial mammals and birds. However, analyses of the Miocene-Recent history of body sizes within 82 molluscan genera show little support for the expectation that the modal size is an evolutionary attractor over geological time.

Effects of oral contraceptive norethindrone on blood-lipid and lipid peroxidation parameters

Considering importance of the lipophilicity of norethindrone (log P=2.97), a significant contributor to its mechanism of action, interaction of the drug with total lipids of goat whole blood have been investigated using phospholipid binding, fatty acid composition and peroxidation phenomena as the parameters under investigation. The objective was to derive an insight into the pharmacodynamic behavior of the drug by correlating biological activity with drug induced changes in lipid constituents. Significant loss in phospholipid along with changes in fatty acid cotmposition was observed after incubation of whole blood with norethindrone at 56 ng/ml (effective contraceptive concentration in blood) in varying periods of time. This may be ascribed to binding affinity of norethindrone with lipid constituents in blood. Lipid binding potential of the drug may have a role in its therapeutic effect. Lipid peroxidation induction potential of norethindrone was quantitatively measured in the context of its toxicity. The results reveal that northindrone caused significant extent of lipid peroxidation. Ascorbic acid, a promising antioxidant, at equivalent human dose levels of 250 mg and 500 mg could significantly reduce norethindrone induced lipid peroxidation.

A new class of potential chloroquine-resistance reversal agents for Plasmodia: syntheses and biological evaluation of 1-(3'-diethylaminopropyl)-3-(substituted phenylmethylene)pyrrolidines

1-(3'-Diethylaminopropyl)-3-(substituted phenylmethylene)pyrrolidines were synthesized and evaluated for CQ-resistant reversal activity. In general the compounds of the series elicit better biological response than their phenylmethyl analogues. The most active compound 4b has been evaluated in vivo in detail, and the results are presented. The possible mode of action of the compounds of this series is by inhibition of the enzyme heme oxygenase, thereby increasing the levels of heme and hemozoin, which are lethal to the parasite.

The nature of bipolar depression: implications for the definition of melancholia

AIM

To examine if melancholic depression is over-represented in those with 'bipolar depression' and, if confirmed, to use that phenomenon to assist the clinical definition of melancholia.

METHODS

We contrast 83 bipolar and 904 unipolar depressed patients on three melancholic sub-typing systems (DSM, Clinical and CORE system) and compare representation of their clinical depressive features.

RESULTS

By all three melancholic sub-typing systems, the bipolar patients were more likely to receive diagnoses of 'melancholia' and of psychotic depression. To the extent that this differential prevalence of depressive sub-types was reflected in varying patterns of clinical features, we so indirectly identified a set of items defining 'melancholia'. By such a strategy, melancholia was most clearly distinguished by behaviourally-rated psychomotor disturbance. While a number of 'endogeneity symptoms' were significantly over-represented, logistic regression analyses refined the set to psychomotor disturbance (both as a symptom and as a sign) and pathological guilt. We also established a distinctly higher prevalence of bipolar depression in those where a refined diagnosis of melancholia was made.

CONCLUSIONS

Bipolar depression appears to be more likely to be 'melancholic' in type, thus providing an indirect strategy for the clinical definition of melancholia.

Ceftriaxone induced lipid peroxidation and its inhibition with various antioxidants: Part II. Evaluation of glutathione and probucol as antioxidants

Exploratory studies on drug induced lipid peroxidation in goat whole blood and its inhibition with antioxidants were carried out using sodium ceftriaxone (CTS) as the representative drug and glutathione and probucol as the representative antioxidants. The studies showed that CTS could induce lipid peroxidation to a significant extent. Lipid peroxidation is a toxicity mediating process, this finding may be correlated with the toxic potential of the drug. It was further found that glutathione and probucol caused significant suppression of CTS induced lipid peroxidation. The results suggest that glutathione and probucol merit further assessment to explore their potential to reduce drug induced lipid peroxidation and thus to increase therapeutic index of the drug by way of reducing toxicity that may be mediated through free radical mechanism.

Evaluation of glutathione and ascorbic acid as suppressors of drug-induced lipid peroxidation

In different sets of experiment lipid peroxidation induction capacity of two drugs, viz., ceftizoxime sodium, a third generation cephalosporin antibiotic, and acyclovir, an antiviral agent, was studied using goat whole blood as the lipid source. Ceftizoxime sodium caused significant extent of lipid peroxidation. Lipid peroxidation being a toxicity mediating process, such observation may be related to the toxic potential of the drug. Insignificant induction of lipid peroxidation was found in case of acyclovir and this is in good agreement with the safety record of the drug. Glutathione and ascorbic acid could significantly reduce ceftizoxime sodium induced lipid peroxidation, suggesting that free radical scavenging action of antioxidants may be exploited by possible antioxidant co-therapy to reduce iatrogenicity of the drug in persons with impaired endogenous antioxidant defence. Glutathione and ascorbic acid appear to be promising candidates for further investigation in this regard.

Costing depression and its management: an Australian study

OBJECTIVE

To examine the cost impact of referral to a Mood Disorders Unit (MDU), by comparing pre-service and post-service costs, and MDU and control samples.

METHOD

We studied tertiary referral MDU patients and a control group of consultants' depressed patients, with the principal comparison intervals being: (i) 12 months prior to and (ii) 6 months following baseline assessment, with costs annualised to allow the impact of assessment and treatment recommendation to be determined. In addition, we assessed any 'personal cost' of depression.

RESULTS

Following baseline assessment, MDU referrals showed a reduction in costs, while controls' costs increased, largely driven by contrasting directions in hospitalisation and social welfare costs. We identify variables associated with high and increased costs, including features of the earlier stages of the disorder, whether social welfare was received, diagnostic subtype and personality dysfunction, with multivariate analyses refining the variable sets. Self-report data indicated that patients judged the 'personal cost' of depression to exceed more formal cost parameters, so that to experience depression is itself depressogenic.

CONCLUSIONS

This first Australian attempt to cost depression and its management in the clinical setting more provides a methodology for wider application in service evaluation studies rather than delivers an unequivocal answer to whether a specialist Mood Disorders Unit is cost efficient or not.

Developmental regulation of amyloid precursor protein at the neuromuscular junction in mouse skeletal muscle

Amyloid precursor protein (APP), associated with Alzheimer's disease plaques, is known to be present in synapses of the brain and in the adult neuromuscular junction (NMJ). In the present study we examined protein and gene expression of APP during the development of mouse skeletal muscle. Using immunocytochemical approaches, we found that APP is first detected in myotube cytoplasm at embryonic day 16 and becomes progressively concentrated at the NMJ beginning at birth until adulthood. The colocalization between APP and acetylcholine receptors at the NMJ is only partial at birth, but becomes complete upon reaching adulthood. We observed that all APP isoforms, including the Kunitz-containing (protease inhibitor or KPI) forms, are up-regulated from birth to postnatal day 5 and then decreased to reach the low levels observed in the adult. This suggests the involvement of APP during the events which lead to a mature mono-innervated synapse. A 92-kDa band, characteristic of a cleaved APP695 isoform and not due to a new muscle-specific alternative spliced form, was observed from postnatal day 15 following completion of polyneuronal synapse elimination. Taken together, these data suggest that skeletal muscle APP may well play a role in the differentiation of skeletal muscle and in the formation and maturation of NMJs.