Environmental risk factors associated with the survival, persistence, and thermal tolerance of Cronobacter sakazakii during the manufacture of powdered infant formula

Cronobacter sakazakii is an opportunistic foodborne pathogen of concern for foods having low water activity such as powdered infant formula (PIF). Its survival under desiccated stress can be attributed to its ability to adapt effectively to many different environmental stresses. Due to the high risk to neonates and its sporadic outbreaks in PIF, C. sakazakii received great attention among the scientific community, food industry and health care providers. There are many extrinsic and intrinsic factors that affect C. sakazakii survival in low-moisture foods. Moreover, short- or long-term pre-exposure to sub-lethal physiological stresses which are commonly encountered in food processing environments are reported to affect the thermal resistance of C. sakazakii. Additionally, acclimation to these stresses may render C. sakazakii resistance to antibiotics and other antimicrobial agents. This article reviews the factors and the strategies responsible for the survival and persistence of C. sakazakii in PIF. Particularly, studies focused on the influence of various factors on thermal resistance, antibiotic or antimicrobial resistance, virulence potential and stress-associated gene expression are reviewed.

Cloud based Agile Methodology Test Automation for Web Application by Using Tanh Activated Clustering and Classification Model (TACC) in Machine Learning

Automatic functional tests are a long-standing issue in software development projects, and they are still carried out manually. The Selenium testing framework has gained popularity as an active community and standard environment for automated assessment of web applications. As a result, the trend setting of web services is evolving on a daily basis, and there is a need to improve automatic testing. The study involves to make the system to understand the experiences of previous test cases and apply new cases to predict the status of test case using Tanh activated Clustering and Classification model (TACC). The primary goal is to improve the model's clustering and classification output. The outcomes show that the TACC model has increased performance and demonstrated that automated testing results can be predicted, which is cost effective and reduces manual effort to a greater extent.

Test Automation of Web Application Login Page by Using Selenium Ide in a Web Browser

Selenium stands as open-source program apparatus aimed at computerization testing. Here, selenium-IDE (Integrated Developments Environment) Testing is investigated, which could be a remarkably vital movement in Program Improvement Handle. It is to look at and alter source code. A high-quality computer program can well be achieved by producing Compelling Testing. This Paper handles a critical in addition to the crucial issue of Program Testing. Testing can well be executed both manually and automatically. This paper sets to do Mechanization Testing through "Selenium". Test cases (TC) are consequently recorded with this web testing tool whilst the analyzer is entering the information in a web application screen.

A Child with Enlarged Extremities - A Case of Macrodystrophia Lipomatosa

Macrodystrophia lipomatosa (ML) is a rare, non-hereditary, developmental anomaly that occurs because of the progressive proliferation of all mesenchymal elements of single or multiple digits or entire extremity, with a disproportionate increase in fibroadipose tissue. Commonly one or few digits of an extremity will be enlarged and present as macrodactyly or as enlarged limb. Lower limb involvement is more common and frequently unilateral. The diagnosis of ML is made by accurate clinical assessment and imaging modalities, such as plain X-ray, computed tomography scan, magnetic resonance imaging, and confirmed by histopathological study. In this case, we described a 10-year-old child who was brought to us with enlarged upper and lower extremities and was diagnosed as a case of ML with the help of clinico-radiological studies and presented here because of focal gigantism involving all four limbs, which is very rare.

Molecular typing of Cyclospora cayetanensis in produce and clinical samples using targeted enrichment of complete mitochondrial genomes and next-generation sequencing

BACKGROUND

Outbreaks of cyclosporiasis, a diarrheal illness caused by Cyclospora cayetanensis, have been a public health issue in the USA since the mid 1990's. In 2018, 2299 domestically acquired cases of cyclosporiasis were reported in the USA as a result of multiple large outbreaks linked to different fresh produce commodities. Outbreak investigations are hindered by the absence of standardized molecular epidemiological tools for C. cayetanensis. For other apicomplexan coccidian parasites, multicopy organellar DNA such as mitochondrial genomes have been used for detection and molecular typing.

METHODS

We developed a workflow to obtain complete mitochondrial genome sequences from cilantro samples and clinical samples for typing of C. cayetanensis isolates. The 6.3 kb long C. cayetanensis mitochondrial genome was amplified by PCR in four overlapping amplicons from genomic DNA extracted from cilantro, seeded with oocysts, and from stool samples positive for C. cayetanensis by diagnostic methods. DNA sequence libraries of pooled amplicons were prepared and sequenced via next-generation sequencing (NGS). Sequence reads were assembled using a custom bioinformatics pipeline.

RESULTS

This approach allowed us to sequence complete mitochondrial genomes from the samples studied. Sequence alterations, such as single nucleotide polymorphism (SNP) profiles and insertion and deletions (InDels), in mitochondrial genomes of 24 stool samples from patients with cyclosporiasis diagnosed in 2014, exhibited discriminatory power. The cluster dendrogram that was created based on distance matrices of the complete mitochondrial genome sequences, indicated distinct strain-level diversity among the 2014 C. cayetanensis outbreak isolates analyzed in this study.

CONCLUSIONS

Our results suggest that genomic analyses of mitochondrial genome sequences may help to link outbreak cases to the source.

Whole-Genome Sequences of Six Listeria monocytogenes Strains Isolated from Food

Here, we report the whole-genome sequences of six Listeria monocytogenes strains isolated from meat and milk products in Switzerland. All of these strains carry premature stop codons or amino acid deletions in inlA.

Whole-Genome Shotgun Sequencing of Three Listeria monocytogenes Strains Isolated from a Ready-to-Eat Salad-Producing Facility in Switzerland

Ready-to-eat (RTE) raw foods harbor the risk of transmitting Listeria monocytogenes from the environment to the consumer. We isolated three strains from a facility producing RTE salad. These strains were used to perform challenge tests on different RTE salad products. Here, we present the shotgun genome sequences of all three of these strains.

Evaluation of the Impact of Varied Carvacrol Concentrations on Salmonella Recovery in Oregano and How Corn Oil Can Minimize the Effect of Carvacrol during Preenrichment

Phenolic compounds, like carvacrol, in oregano interfere with the detection of foodborne pathogens such as Salmonella enterica. Carvacrol concentration varies based on plant cultivars and growth region. Six oregano cultivars were used to compare the impact of carvacrol concentration on Salmonella and to evaluate the effectiveness of corn oil to help increase Salmonella survival for detection. The results of Agilent 1200 series high-performance liquid chromatography analysis showed that carvacrol concentration in the six oregano cultivars ranged from 64 to 11,200 ppm. Oregano samples were artificially contaminated with S. enterica and were preenriched in Trypticase soy broth with or without 2% (v/v) corn oil. After 18 to 24 h at 37°C, aliquots were transferred to selective enrichment broths. Salmonella was recovered onto xylose lysine Tergitol 4 agar. Six Salmonella serovars were compared, and recovery varied based on carvacrol concentration and serovar. Samples with higher concentrations of carvacrol showed Salmonella recovery only when they were preenriched with corn oil. Based on metagenomic analysis, the microflora associated with the oregano also varied per cultivar. The results show that, as carvacrol levels increased, Salmonella survival decreased. However, the addition of corn oil to the preenrichment broth can minimize the antimicrobial effects of the phenolic compounds, thus allowing for increased detection of Salmonella from oregano cultivars.

Salmonella enterica serovar Infantis from Food and Human Infections, Switzerland, 2010-2015: Poultry-Related Multidrug Resistant Clones and an Emerging ESBL Producing Clonal Lineage

Objectives: The aim of this study was to characterize a collection of 520 Salmonella enterica serovar Infantis strains isolated from food (poultry meat), human infections and environmental sources from the years 2010, 2013 and 2015 in Switzerland. Methods: We performed antimicrobial susceptibility testing and pulsed-field gel electrophoresis (PFGE) analysis on all 520 S. Infantis isolates, and whole genome sequencing (WGS) on 32 selected isolates. Results: The majority (74.8%) of the isolates was multidrug resistant (MDR). PFGE analysis revealed that 270 (51.9%) isolates shared an identity of 90%. All isolates subjected to WGS belonged to sequence type (ST) 32 or a double-locus variant thereof (one isolate). Seven (21.9%) of the sequenced isolates were phylogenetically related to the broiler-associated clone B that emerged in Hungary and subsequently spread within and outside of Europe. In addition, three isolates harboring blaCTX-M-65 on a predicted large (∼320 kb) plasmid grouped in a distinct cluster. Conclusion: This study documents the presence of the Hungarian clone B and related clones in food and human isolates between 2010 and 2015, and the emergence of a blaCTX-M-65 harboring MDR S. serovar Infantis lineage.

Increased secretion of exopolysaccharide and virulence potential of a mucoid variant of Salmonella enterica serovar Montevideo under environmental stress

During an investigation to increase the recovery of Salmonella enterica from Oregano, an increased expression of exopolysaccharide was induced in Salmonella serovar Montevideo. The atypical mucoid (SAL242S) and the non-mucoid (SAL242) strains of Montevideo were compared and characterized using various methods. Serotyping analysis demonstrated that both strains are the same serovar Montevideo. Electron microscopy (EM) of cultured SAL242S cells revealed the production of a prominent EPS-like structure enveloping aggregates of cells that are composed of cellulose. Mucoid cells possessed a higher binding affinity for Calcofluor than that of the non-mucoid strain. Genotypic analysis revealed no major genomic differences between these morphotypes, while expression analyses using a DNA microarray shows that the mucoid variant exhibited heightened expression of genes encoding proteins produced by the SPI-1 type III secretion system. This increased expression of SPI1 genes may play a role in protecting Salmonella from environmental stressors. Based on these observations, Salmonella serovar Montevideo mucoid variant under stressful or low-nutrient environments presented atypical growth patterns and phenotypic changes, as well as an upregulated expression of virulence factors. These findings are significant in the understanding of survival abilities of Salmonella in a various food matrices.

Whole Genome DNA Sequence Analysis of Salmonella subspecies enterica serotype Tennessee obtained from related peanut butter foodborne outbreaks

Establishing an association between possible food sources and clinical isolates requires discriminating the suspected pathogen from an environmental background, and distinguishing it from other closely-related foodborne pathogens. We used whole genome sequencing (WGS) to Salmonella subspecies enterica serotype Tennessee (S. Tennessee) to describe genomic diversity across the serovar as well as among and within outbreak clades of strains associated with contaminated peanut butter. We analyzed 71 isolates of S. Tennessee from disparate food, environmental, and clinical sources and 2 other closely-related Salmonella serovars as outgroups (S. Kentucky and S. Cubana), which were also shot-gun sequenced. A whole genome single nucleotide polymorphism (SNP) analysis was performed using a maximum likelihood approach to infer phylogenetic relationships. Several monophyletic lineages of S. Tennessee with limited SNP variability were identified that recapitulated several food contamination events. S. Tennessee clades were separated from outgroup salmonellae by more than sixteen thousand SNPs. Intra-serovar diversity of S. Tennessee was small compared to the chosen outgroups (1,153 SNPs), suggesting recent divergence of some S. Tennessee clades. Analysis of all 1,153 SNPs structuring an S. Tennessee peanut butter outbreak cluster revealed that isolates from several food, plant, and clinical isolates were very closely related, as they had only a few SNP differences between them. SNP-based cluster analyses linked specific food sources to several clinical S. Tennessee strains isolated in separate contamination events. Environmental and clinical isolates had very similar whole genome sequences; no markers were found that could be used to discriminate between these sources. Finally, we identified SNPs within variable S. Tennessee genes that may be useful markers for the development of rapid surveillance and typing methods, potentially aiding in traceback efforts during future outbreaks. Using WGS can delimit contamination sources for foodborne illnesses across multiple outbreaks and reveal otherwise undetected DNA sequence differences essential to the tracing of bacterial pathogens as they emerge.

Evaluation of corn oil as an additive in the pre-enrichment step to increase recovery of Salmonella enterica from oregano

Phenolic compounds associated with essential oils of spices and herbs possess a variety of antioxidant and antimicrobial properties that interfere with Salmonella detection from fresh and dried products. Finding a compound to neutralize the effect of these antimicrobial compounds, while allowing Salmonella growth during pre-enrichment, is a crucial step in both traditional pathogen isolation and molecular detection from these foods. This study evaluated the effectiveness of corn oil as a component of the pre-enrichment broth to counteract antimicrobial compounds properties and increase the recovery of Salmonella from spices. Oregano samples artificially contaminated with Salmonella enterica were pre-enriched in modified Buffered Peptone Water (mBPW) supplemented with and without 2% (vol/vol) corn oil respectively. Samples were incubated overnight at 37 °C. The results showed that recovery of Salmonella from oregano samples was increased by ≥50% when pre-enriched with corn oil. Serovars were confirmed using a PCR serotyping method. In addition, shot-gun metagenomics analyses demonstrated bacterial diversity and the effect of corn oil on the relative prevalence of Salmonella in the oregano samples. Modifying pre-enrichment broths with corn oil improved the detection and isolation of Salmonella from oregano, and may provide an alternative method for pathogen detection in dried food matrices such as spices.

Angelman syndrome in three biological siblings: Focusing on the neuropsychiatric domain

Angelman syndrome (AS) is a neurogenetic disorder that usually presents with delayed motor milestones, ataxic gait, mental retardation, language disorder, seizures, sleep disturbances, characteristic facial features, and happy demeanor. The genetic abnormality of AS has been located on chromosome 15q11-q13. The AS gene(s) is exclusively expressed from the maternal chromosome. Loss of the maternally contributed AS region can occur by deletion, paternal uniparental disomy, imprinting defects, mutation of the ubiquitin-protein ligase (UBE3A) gene, and by yet unidentified mechanisms. Deletion of maternal chromosome accounts for most of the cases of AS with imprinting accounting for 2%-5% of cases. In imprinting inheritance, offsprings of carrier mothers are theoretically at 50% risk of having AS. Familial occurrence of AS has been reported. Here, we highlighted the rare incident of AS in three biological siblings and their neuropsychiatric manifestations as well as different psychosocial aspects.

Pan-genome analysis of the emerging foodborne pathogen Cronobacter spp. suggests a species-level bidirectional divergence driven by niche adaptation

Background

Members of the genus Cronobacter are causes of rare but severe illness in neonates and preterm infants following the ingestion of contaminated infant formula. Seven species have been described and two of the species genomes were subsequently published. In this study, we performed comparative genomics on eight strains of Cronobacter, including six that we sequenced (representing six of the seven species) and two previously published, closed genomes.

Results

We identified and characterized the features associated with the core and pan genome of the genus Cronobacter in an attempt to understand the evolution of these bacteria and the genetic content of each species. We identified 84 genomic regions that are present in two or more Cronobacter genomes, along with 45 unique genomic regions. Many potentially horizontally transferred genes, such as lysogenic prophages, were also identified. Most notable among these were several type six secretion system gene clusters, transposons that carried tellurium, copper and/or silver resistance genes, and a novel integrative conjugative element.

Conclusions

Cronobacter have diverged into two clusters, one consisting of C. dublinensis and C. muytjensii (Cdub-Cmuy) and the other comprised of C. sakazakii, C. malonaticus, C. universalis, and C. turicensis, (Csak-Cmal-Cuni-Ctur) from the most recent common ancestral species. While several genetic determinants for plant-association and human virulence could be found in the core genome of Cronobacter, the four Cdub-Cmuy clade genomes contained several accessory genomic regions important for survival in a plant-associated environmental niche, while the Csak-Cmal-Cuni-Ctur clade genomes harbored numerous virulence-related genetic traits.

Reactome: a database of reactions, pathways and biological processes

Reactome (http://www.reactome.org) is a collaboration among groups at the Ontario Institute for Cancer Research, Cold Spring Harbor Laboratory, New York University School of Medicine and The European Bioinformatics Institute, to develop an open source curated bioinformatics database of human pathways and reactions. Recently, we developed a new web site with improved tools for pathway browsing and data analysis. The Pathway Browser is an Systems Biology Graphical Notation (SBGN)-based visualization system that supports zooming, scrolling and event highlighting. It exploits PSIQUIC web services to overlay our curated pathways with molecular interaction data from the Reactome Functional Interaction Network and external interaction databases such as IntAct, BioGRID, ChEMBL, iRefIndex, MINT and STRING. Our Pathway and Expression Analysis tools enable ID mapping, pathway assignment and overrepresentation analysis of user-supplied data sets. To support pathway annotation and analysis in other species, we continue to make orthology-based inferences of pathways in non-human species, applying Ensembl Compara to identify orthologs of curated human proteins in each of 20 other species. The resulting inferred pathway sets can be browsed and analyzed with our Species Comparison tool. Collaborations are also underway to create manually curated data sets on the Reactome framework for chicken, Drosophila and rice.

The BioPAX community standard for pathway data sharing

BioPAX (Biological Pathway Exchange) is a standard language to represent biological pathways at the molecular and cellular level. Its major use is to facilitate the exchange of pathway data (http://www.biopax.org). Pathway data captures our understanding of biological processes, but its rapid growth necessitates development of databases and computational tools to aid interpretation. However, the current fragmentation of pathway information across many databases with incompatible formats presents barriers to its effective use. BioPAX solves this problem by making pathway data substantially easier to collect, index, interpret and share. BioPAX can represent metabolic and signaling pathways, molecular and genetic interactions and gene regulation networks. BioPAX was created through a community process. Through BioPAX, millions of interactions organized into thousands of pathways across many organisms, from a growing number of sources, are available. Thus, large amounts of pathway data are available in a computable form to support visualization, analysis and biological discovery.

Reactome knowledgebase of human biological pathways and processes

Reactome (http://www.reactome.org) is an expert-authored, peer-reviewed knowledgebase of human reactions and pathways that functions as a data mining resource and electronic textbook. Its current release includes 2975 human proteins, 2907 reactions and 4455 literature citations. A new entity-level pathway viewer and improved search and data mining tools facilitate searching and visualizing pathway data and the analysis of user-supplied high-throughput data sets. Reactome has increased its utility to the model organism communities with improved orthology prediction methods allowing pathway inference for 22 species and through collaborations to create manually curated Reactome pathway datasets for species including Arabidopsis, Oryza sativa (rice), Drosophila and Gallus gallus (chicken). Reactome's data content and software can all be freely used and redistributed under open source terms.

Reactome: a knowledge base of biologic pathways and processes

Reactome, an online curated resource for human pathway data, can be used to infer equivalent reactions in non-human species and as a tool to aid in the interpretation of microarrays and other high-throughput data sets.

Reactome http://www.reactome.org, an online curated resource for human pathway data, provides infrastructure for computation across the biologic reaction network. We use Reactome to infer equivalent reactions in multiple nonhuman species, and present data on the reliability of these inferred reactions for the distantly related eukaryote Saccharomyces cerevisiae. Finally, we describe the use of Reactome both as a learning resource and as a computational tool to aid in the interpretation of microarrays and similar large-scale datasets.

Is low serum tocopherol in Wilson's disease a significant symptom?

BACKGROUND

Free radical mediated injury is increasingly recognized in many metabolic diseases including Wilson's disease (WD). Use of antioxidants as an adjunctive therapy in WD may have therapeutic significance.

AIM

The aim of the study was to correlate serum levels of tocopherols with serum copper and ceruloplasmin and clinical status of these patients.

METHODS

Serum levels of tocopherol of were measured spectrophotometrically using the Emmerie-Engel reaction in 34 patients from a large cohort of WD being followed up at a tertiary care center.

RESULTS

Majority of patients were male (M/F=23:11). The mean serum copper was 43.6+/-26.2 microg/dl (range=10-121 microg/dl) and serum ceruloplasmin was 5.6+/-5.5 mg/dl (range=0-30 mg/dl). The mean serum tocopherol level was 0.68+/-0.18 mg/dl (range=0.23-1.14 mg/dl) and compared to the control (1.07+/-0.17 mg/dl), nearly 59% of patients had decreased levels (p<0.001). No significant correlation was noted between low serum tocopherol levels and serum copper levels, Mini Mental Status Examination (MMSE) scores and CHU staging. However, serum tocopherol levels were lower in patients with relatively short duration of treatment (7.8 years vs. 12.4 years).

CONCLUSION

Decreased levels of serum tocopherol were detected in 59% of patients compared to controls. However, low tocopherol levels did not correlate with clinical status or biochemical parameters of WD, except for relatively shorter duration of treatment. Further studies, especially in newly diagnosed patients, need to be done to validate the role of low tocopherol levels in Wilson's disease.

Pre and post betahistine therapy 99m Tc - HMPAO brain spect studies in patients with vertigo

Vertebro basilar insufficiency (VBI) is a well known cause of vertigo. Brain Single Photon Emission Computed Tomography (SPECT) is an important diagnostic tool to detect and to quantitate the perfusion abnormalities in different areas of the brain. Effect of an antivertigo drug Betahistine on improving the hypoperfusion in different areas of the brain in vertigo patients was studied using brain SPECT. Betahistine at a dose of 16 mg three times daily was shown to improve perfusion in the hypoperfused areas of the brain resulting in relief from symptoms of vertigo. The cerebellar region, which is the most important area involved in vertigo patients with vascular pathology, showed almost complete normalisation of perfusion following Betahistine therapy.

Queering Bollywood: alternative sexualities in popular Indian cinema

In this essay, I demonstrate through numerous examples taken from four identifiable Hindi film subgenres queer themes which, though nontransgressive in their native Indian context, acquire subversive value and serve as queer points of identification when viewed from a non-nationalist bias. Watching particular films with this "queer diasporic viewing practive," sex/gender play which is normative (yet still coded) in the land of the films' production can be reclaimed as queer through the differently subjective lens of transnational spectatorship, a lens removed from patriarchy, sexism, and homophobia. This particularly becomes apparent in the Bollywood dance sequence-the frequent site of Hindi sex/gender play-whose coded queer desires are much easier to de-code (or re-code) when in the diaspora.

Effect of different lithium priming schedule on pilocarpine-induced status epilepticus in rats

The conventional method of inducing status epilepticus by injecting pilocarpine 24 h after lithium chloride (LiCl) administration lacks kinetic correlate. Therefore, the present study was conducted to see the effect of altering the time schedule of lithium administration (from 2 to 72 h) on the convulsive behavior in response to pilocarpine challenge in rats. It was observed that reducing the pretreatment time of lithium from 24 to 2 h produced convulsions in 100% of the rats. However, incidence of convulsions decreased when lithium pretreatment time was increased to 48 h and no convulsions were recorded with 72-h lithium time schedule. The neuronal damage assessed histologically and the effectiveness of diazepam was similar irrespective of time schedule. This study provides evidence that LiCl pretreatment schedule can be adopted at any time between 2 to 24 h to suit the convenience and objectives of the experiment.

Recovery of sleep after fetal preoptic transplantation in medial preoptic area-lesioned rats

Changes in sleep after fetal preoptic (POA) tissue transplantation were studied in rats which had been made insomniac by a medial preoptic area (mPOA) lesion. Two days after the N-methyl D-aspartic acid (NMDA) lesion of the mPOA, fetal POA tissues (obtained from 14- to 17-day-old fetuses) were transplanted into the lesioned mPOA. Insomnia was less marked in these animals, as compared to nontransplanted lesioned rats, even on the 4th day after transplantation. The quantum of sleep nearly attained the prelesion level by the 20th day. Body weight also showed recovery after transplantation. Rectal temperature, which was increased by the lesion of the mPOA, remained unaltered even after the transplantation. These results suggest that the recovery of sleep and rectal temperature may follow different time courses. Surviving transplanted neurons were seen at the site of lesion on postmortem examination. Humoral interaction between the host and the transplant may be responsible for the early recovery of sleep, though the establishment of neural connections between the host and transplant might have contributed to the later recovery. This is the first study to show the recovery of sleep function in insomniac animals after fetal preoptic tissue transplantation. However, the specificity of the POA fetal tissue, in comparison with other neural tissues to promote sleep recovery, remains to be established.

Role of medial preoptic area beta adrenoceptors in the regulation of sleep-wakefulness

The role of the medial preoptic area (mPOA) beta adrenergic receptors in the regulation of sleep-wakefulness (S-W) was investigated in this study. S-W was assessed on the basis of polygraphic recording of EEG, EMG and EOG in free moving rats. Intracerebral microinjection of beta agonist, isoproterenol, into the mPOA produced arousal. The study was also conducted on another set of rats in which noradrenergic (NE) innervation to the mPOA was destroyed by injecting 6-hydroxydopamine into the ventral noradrenergic bundle, in the brain stem. Local application of isoproterenol, into the mPOA, in these animals, did not produce any significant change in S-W. Thus, the increase in awake period obtained on isoproterenol administration was the result of its action on the presynaptic NE terminals. Possible involvement of other responses in the isoproterenol induced increase in wakefulness, is discussed.

Fetal dopaminergic neurons transplanted to the normal striatum of neonatal or adult rats and to the denervated striatum of adult rats

Fetal ventral mesencephalon from the 15th gestational day was grafted into the striatum of neonatal and adult rats. In one group of adult rats, fetal nigra was transplanted into normal striatum. In a second group, the tissue was transplanted at sites where dopaminergic fibers were denervated with 6-hydroxydopamine. The behavior of the dopaminergic neurons and glial reactions were studied by staining with cresyl violet to localize the transplants and by immunolabeling tyrosine hydroxylase (TH) and glial fibrillary acidic protein. In normal adults, the transplants were small. At the edge of the transplants, TH-positive neurons were packed into clusters, and an interface without any significant crossover of TH-positive fibers was present. Glial reaction was minimal in and around the transplant. In the denervated striatum, transplants were generally larger than those in normal striatum and surrounded by a glial scar. TH-positive neurons were both closely packed and loosely arranged at the periphery of the transplants. Processes could be clearly defined and could be traced to the adjacent host striatum through the TH-free denervated area. In neonates, the transplants were large and at times extended beyond the striatum. Most TH-positive neurons were arranged linearly along the periphery of the transplant. Cell bodies were widely separated and a well-developed neuropil was present. Fibers from the transplant mingled freely with the host striatum without any interface. In all three transplant groups, tracing the TH-positive neurites was easy because they were thicker and coarser than other elements. No apparent glial reaction occurred in the neonates. Thus, the growth and maturation of dopaminergic neurons seemed to vary in different environments. The most conducive environment appears to be neonatal brain in which growth factors are readily available.

Ultrastructure of developing substantia nigra in humans

Electron microscopy of the maturing neurons and developing and maturing synapses in the substantia nigra of 14 human embryos/foetuses of 8-24 weeks of gestation are reported. At 8 weeks, cells were immature with very little cytoplasm and cellular organelles. Contact sites of processes appeared more electron dense than the other areas. At 12 weeks, many of the cells had acquired more cytoplasm and cellular organelles and could be identified as neurons. Asymmetric synapses with clear, round synaptic vesicles also were identifiable at this age. Such synapses, first to appear in the developing substantia nigra, are reported to be formed by recurrent collateral nigro-striatal fibres. Substance P fibres from the striatum also are contributing to this type of synapse. At 15-16 weeks, not only was the number of such synapses increased, but many appeared morphologically mature. Symmetric synapses having clear round vesicles along with a few dense core vesicles also appeared at this stage, suggesting striatal input. By 24 weeks of gestation, most of the neurons had cytological features comparable to that of the mature neurons. There was an increase in the total number of synapses and the individual variety from 15 to 24 weeks of gestation. The present study indicates that synaptogenesis starts at 8 weeks and continues beyond 24 weeks of gestation.

Biparietal diameter: a useful measure for determining gestational age of human abortuses

BACKGROUND

The crown-rump length is conventionally used to determine the age of human abortuses. However, it is not reliable as it is dependent on the positioning of the conceptus. We compared this with the biparietal diameter and foot length for determining the gestational age.

METHODS

Different measurements, commonly used to assess gestational age, were measured in 146 human abortuses for which an accurate obstetric history could not be elicited. Measurements taken were crown-rump length, biparietal diameter and foot length. These were correlated with the observations at antenatal examinations before finalizing the approximate age.

RESULTS

Multiple regression analysis of the data indicated that of the three measurements, the biparietal diameter was the most reliable for determining foetal gestational age between 8 and 26 weeks. The age determined with the biparietal diameter correlated well with that of abortuses with an accurate obstetric history.

CONCLUSION

The biparietal diameter of a human foetus may be used to determine its age if the obstetric history regarding the period of gestation is vague or not available.

Long-term nigral transplants in rat striatum: an electron microscopic study

The substantia nigra of gestation day 14 was transplanted into the striatum of 3-4-month-old rats to investigate the transplants ultrastructurally at the end of 2 years, as a follow-up to our previous studies. Transplants were of small size in all 10 specimens taken for this study. The changes observed in the transplant and in the interface region with the host striatum were: thickening of the blood vessel walls, perivascular cuffing with lymphocytes and macrophages loaded with tissue debris, degenerating neurons and hypertrophied astroglia containing dense granules indicating ageing or reaction to degeneration and glial processes. The number of surviving neurons in the transplants was small. These were smaller in size and had very few intracytoplasmic membraneous organelles. A higher content of intracytoplasmic ageing lipofuscin pigment was present than in host neurons and age-matched nigral neurons. Synapses were few, and their number varied among transplants. Generally, the synapses were at the interface with the host tissue. The changes observed in all the 2-year-old transplants suggest premature ageing or a slow rejection process. Slow rejection is a possibility, because these rats are only stock-bred, not inbred, and hence they are not completely immunologically compatible.

Cell surface molecules (NCAM and L1) in intrastriatal transplants of embryonic mesencephalon in rats

Cell surface molecules, NCAM and L1, reported to have a role in synaptogenesis, growth and fasciculation of the neurites in the brain, were traced in the embryonic nigral transplants in the host striatum of adult rats. Substantia nigra of five, 15 and 25 postnatal days were also examined for the same molecules. Tyrosine hydroxylase label was used as a marker to localize the nigral neurons and glial fibrillary acidic protein to detect if glial scar present. In the control as well as transplants large neurons had expressed tyrosine hydroxylase. By 15th postnatal day tyrosine hydroxylase neurons appeared mature and were scattered, suggesting a well-formed neuropil. NCAM and L1 reaction was seen as a peripheral rim in most of the cells on the fifth postnatal day. The reaction was mainly in relation to the large cells and more extensive on the 15th day. Thereafter on the 25th day, activity was negligible. Large neurons demonstrated strong reactivity for NCAM and L1 during early post-transplantation days. After 30 days only smaller cells were reactive, many of which could be identified as neurons. Strong reaction for these molecules was present only until 60 days, though faint reaction could be detected even on the 90th day. These observations indicate that the growth promoting molecules, the type seen in the neonatal period, can be detected normally only until the neurons mature. Prolonged expression of these molecules by the grafted neurons indicate delay in the maturation of these cells due to absence of adequate target sites for synaptic connections. Some of the smaller cells expressing these molecules after 30 days of transplantation could be astroglia, either proliferating or reactive.

Developing substantia nigra in human: a qualitative study

Midbrains from 43 fresh human embryos and fetuses at 8-22 weeks of gestation were processed for routine histology, Golgi staining, tyrosine hydroxylase (TH) immunolabelling and retrograde tracing with the fluorescent dye DiI. Cells were immature and densely packed between 8 and 10 weeks. By 13 weeks cells could be identified as neurons and glia. Neurons matured gradually and achieved adult characteristics by 20-22 weeks. Neurons in the paramedian regions of the tegmentum, raphae region and substantia nigra were positive for TH from 13 weeks onwards, the earliest age group used for this technique. The presence of TH-positive neurons in the paramedian part of the tegmentum until 18 weeks and radial glial fibers extending from the aqueductal lining to the ventral part until 20 weeks were suggestive of migration of neurons to the ventral mesencephalon region. DiI labelling of the neurons and fibers of ipsilateral nigra from the caudate as early as 10 weeks demonstrated early nigrostriatal connections. The mature nature of the neurons appeared only by 13 weeks by this method. The present study shows that the nigral neurons in the human migrate and mature until mid-gestation. The nigrostriatal connection at 10 weeks suggests a trophic influence of nigra on the proliferating and maturing neurons of the striatum.

Changes in sleep-wakefulness after kainic acid lesion of the preoptic area in rats

The role of the preoptic area (POA) neurons in the regulation of sleep-wakefulness (S-W) has been investigated in this study. The cell-specific neurotoxin, kainic acid (KA), was injected (0.8 microgram in 0.2 microliter) intracerebrally for lesioning of the POA. S-W was assessed (on the basis of EEG, EMG, and EOG recordings) for a day before bilateral lesion of the POA, and for 3 weeks after the lesion. There was an increase in wakefulness, and a decrease in all the stages of sleep after KA lesion of the POA. The reduction in deep slow wave sleep (S2) and REM sleep (PS) were more marked than light slow wave sleep (S1), and these had not shown any recovery even after 3 weeks of lesion. Two days after the lesion, the reduction in sleep was much more marked during the daytime than at night. There was an increase in locomotor activity, especially during the daytime, though it was only statistically significant on the 6th and the 10th day after the lesion. This study shows that the POA neurons are involved in the induction and maintenance of sleep. The lesion did not have a long lasting effect on the circadian distribution of sleep but the changes in locomotor activity seem to persist for a longer period.

Developing dentate nucleus in man: a qualitative and quantitative study

Histological and quantitative studies were carried out in dentate nucleus (DN) of 14 human fetuses of gestational ages ranging from 10 weeks to 28 weeks in Nissl stained sections. The dentate nucleus was already well delineated at 11 weeks, but the adult profile was attained only by 27-28 weeks. The magnocellular dorsomedial region and the parvocellular ventrolateral region became apparent at 17-18 weeks. The numerical density of neurons showed a steady decline with advancing gestational age. However, the absolute neuronal count until 19-20 weeks was 367.1 x 10(3) followed by a count of 249.5 x 10(3) at 22-23 weeks. The reduction in the count between the two periods was significant and coincided with cell death which was striking between 19 and 23 weeks. The glial cell population continued to increase with advancing gestational age. The occurrence of significant neuronal cell death and its probable role in the developing human DN is reported for the first time.

Fetal brain transplantation in kainic acid lesioned caudate nucleus of adult rats

This study confirmed that bilateral kainic acid (KA) injection at the caudate produces aphagia and adipsia in rats. The reduction in food and water intake was fatal after a higher dosage of the drug. To test the effect of transplantation on the mortality rate, KA was first injected in the left caudate, in one set of rats. After a gap of three days, fetal striatal tissue was unilaterally transplanted at this lesioned site, along with a second injection of KA in the right caudate. Successful transplantation, as ascertained morphologically, did not significantly alter the mortality rate. The morphometric study revealed that the neurons of the transplant were larger in size, and their numerical density lower than those of the caudate of normal rats. Only very few neurons of the transplant developed functional connectivity with the host, as demonstrated by electrophysiological studies.

Adrenal medullary autografts in anterior eye chamber, lateral ventricle and striatum of adult rats: a long term study

The neurobiological basis for the short-term recovery in Parkinson's patients and experimental animals grafted with adrenal medulla is not yet clear. Structural details of the grafted chromaffin cells are also not available. In the present study, autografts of adrenal medulla in the anterior eye chamber, lateral ventricle and striatum of adult rats were studied for 360 days. Though a large number of cells degenerated, a few healthy chromaffin cells survived up to 360 days in the anterior eye chamber. In the ventricular and striatal regions, cells degenerated more rapidly, and a few surviving cells were seen only up to 120 and 150 days, respectively. Degeneration of the cells was evident from the alteration of the cytoplasmic granules, appearance of vacuoles and lysosomes, rapid decline in the number of TH and DBH positive cells and diffusion of enzymes in the intercellular region. Only lymphocytes and connective tissue cells were seen in the ventricle after 120 days, while outlines of a few chromaffin cells and background fluorescence were still evident in the striatum up to 150 days. In some of the intrastriatal transplants, morphologically identifiable Schwann cells were present and, in one transplant, there was evidence of myelination of axons by Schwann cells. These axons were obviously derived from the adjacent host tissue. From the findings it has been concluded that autografts of adrenal medulla survive for only a limited period of time on transplantation to the central nervous system and anterior eye chamber. Survival seemed to be better in the anterior eye chamber than at the sites preferentially chosen for treating Parkinson's patients or experimental animals.

Fetal nigral transplants in the lateral ventricle of adult rats. A long-term morphological study

The substantia nigra from rats of 16 and 17 gestational days grafted into the lateral ventricle of adult rats grew into isolated or partially integrated transplants in 80% of the rats. The morphological details of the transplants were studied at intervals of 30-360 days. The neurons grew, differentiated and were comparable to age-matched controls until 150 days. Thereafter, the neurons showed progressive aging changes like dendritic thickening, clear spaces, membrane-bound vacuoles and increase in lysosomes in the cytoplasm. The numerical density per unit volume (Nv) of normal neurons significantly decreased with simultaneous increase in Nv of glial cells by 360 days. These changes were slower to develop in the partially integrated transplants: it is concluded that target tissue interaction is necessary for prolonged survival of the grafted tissue.

Ageing changes in the transplants of fetal substantia nigra grafted to striatum of adult rat

Fetal nigral neurons from 16 and 17 gestational days were transplanted into the intact striatum of adult rat. On different post-transplantation days (30-360 days), the structural and immunohistochemical details of the transplants were studied. The grafted neurons matured and showed phenotypical characteristics comparable to that of normal nigral neurons in adult rats until 180 days. Tyrosine hydroxylase-positive neurons were seen not only in the transplant but also in the adjacent host striatum. Tyrosine hydroxylase-positive fibres were also seen extending for a short distance into the host striatum. A large number of synapses in the transplants were of asymmetric type, containing clear round vesicles. These synapses resembled the few intrinsic type present in the normal substantia nigra. On the other hand, the predominant type 2 synapses with pleomorphic vesicles in the normal nigra were infrequently encountered in the transplants. On the 300th day, the cytoplasm of a few of the neurons showed ageing changes in the form of clear spaces, paucity of organelles especially rough endoplasmic reticulum, membrane-bound vacuoles and increase in the lipofuscin population. In addition, localized thickening of the soma and the dendrites were seen in relation to randomly distributed neurons. By 360 days, more than one quarter (26%) of the total neurons showed these changes indicating ageing. The number per unit volume of normal neurons decreased significantly when compared to the transplants on 60 and 90 days. In the substantia nigra of age-matched control, except for an increase in the lysosomal population, other ageing changes were not detectable. The neurons of intact substantia nigra of the host rat, chronologically 4-8 months older than the transplanted neurons, also appeared normal but for lipofuscin granules. The present study provides morphological evidence for rapid ageing of neurons in the long term nigral transplants. These observations raise fresh doubts regarding permanent survival of grafted neurons in the host brain. Studies so far conducted are after prior nigral lesions. Trophic factors following lesions of the host tissue may have influenced the long term survival of the transplanted neurons. On the other hand, such changes may have been missed since no detailed morphological investigations of the long term transplants have been done so far.