Early-onset parkinsonism associated with PINK1 mutations: frequency, genotypes, and phenotypes

OBJECTIVE

To assess the prevalence, nature, and associated phenotypes of PINK1 gene mutations in a large series of patients with early-onset (<50 years) parkinsonism.

METHODS

The authors studied 134 patients (116 sporadic and 18 familial; 77% Italian) and 90 Italian controls. The whole PINK1 coding region was sequenced from genomic DNA; cDNA was analyzed in selected cases.

RESULTS

Homozygous pathogenic mutations were identified in 4 of 90 Italian sporadic cases, including the novel Gln456Stop mutation; single heterozygous truncating or missense mutations were found in another 4 Italian sporadic cases, including two novel mutations, Pro196Leu and Gln456Stop. Pathogenic mutations were not identified in the familial cases. Novel (Gln115Leu) and known polymorphisms were identified with similar frequency in cases and controls. In cases carrying single heterozygous mutation, cDNA analysis detected no additional mutations, and revealed a major pathogenic effect at mRNA level for the mutant C1366T/Gln456Stop allele. All patients with homozygous mutations had very early disease onset, slow progression, and excellent response to l-dopa, including, in some, symmetric onset, dystonia at onset, and sleep benefit, resembling parkin-related disease. Phenotype in patients with single heterozygous mutation was similar, but onset was later.

CONCLUSIONS

PINK1 homozygous mutations are a relevant cause of disease among Italian sporadic patients with early-onset parkinsonism. The role of mutations found in single heterozygous state is difficult to interpret. Our study suggests that, at least in some patients, these mutations are disease causing, in combination with additional, still unknown factors.

Spatial segregation of mRNA encoding myelin-specific proteins

The cellular and subcellular distributions of mRNAs encoding three myelin-specific proteins--myelin basic protein (MBP), proteolipid protein (PLP), and Po protein--were studied in tissue sections of developing rat nervous systems by in situ hybridization. The developmental appearance of these mRNAs closely paralleled the appearance of the proteins they encode as determined by immunocytochemistry. mRNA encoding the extrinsic membrane protein, MBP, was concentrated around oligodendrocyte and Schwann cell nuclei during initial stages of myelination; as myelination proceeded, MBP mRNA became distributed diffusely over myelinated fibers. In contrast, mRNAs encoding the intrinsic membrane proteins, PLP and Po, remained concentrated around oligodendrocyte (PLP) and Schwann cell (Po) nuclei at all stages of myelination. These results establish that myelinating cells spatially segregate certain myelin-specific mRNAs. The presence of MBP mRNA within the cytoplasmic domains of myelin internodes indicates that protein sorting during myelination involves transportation of mRNA to specific subcellular sites.

The G6055A (G2019S) mutation in LRRK2 is frequent in both early and late onset Parkinson's disease and originates from a common ancestor

BACKGROUND

Mutations in the gene Leucine-Rich Repeat Kinase 2 (LRRK2) were recently identified as the cause of PARK8 linked autosomal dominant Parkinson's disease.

OBJECTIVE

To study recurrent LRRK2 mutations in a large sample of patients from Italy, including early (<50 years) and late onset familial and sporadic Parkinson's disease.

RESULTS

Among 629 probands, 13 (2.1%) were heterozygous carriers of the G2019S mutation. The mutation frequency was higher among familial (5.1%, 9/177) than among sporadic probands (0.9%, 4/452) (p<0.002), and highest among probands with one affected parent (8.7%, 6/69) (p<0.001). There was no difference in the frequency of the G2019S mutation in probands with early v late onset disease. Among 600 probands, one heterozygous R1441C but no R1441G or Y1699C mutations were detected. None of the four mutations was found in Italian controls. Haplotype analysis in families from five countries suggested that the G2019S mutation originated from a single ancient founder. The G2019S mutation was associated with the classical Parkinson's disease phenotype and a broad range of onset age (34 to 73 years).

CONCLUSIONS

G2019S is the most common genetic determinant of Parkinson's disease identified so far. It is especially frequent among cases with familial Parkinson's disease of both early and late onset, but less common among sporadic cases. These findings have important implications for diagnosis and genetic counselling in Parkinson's disease.

Major co-localization of the extracellular-matrix degradative enzymes heparanase and gelatinase in tertiary granules of human neutrophils

The expression of cell-surface adhesion proteins and the release of extracellular-matrix degradative enzymes constitute crucial processes for the attachment of neutrophils to the endothelium and for the subsequent extravasation of these cells through the endothelial layer. We have analysed in resting human neutrophils the subcellular localization of heparanase, a heparan-sulphate-degrading endoglycosidase that can degrade basement-membrane components, thereby facilitating neutrophil passage into the tissue during an inflammatory reaction. By subcellular fractionation of postnuclear supernatants from resting human neutrophils on continuous sucrose gradients, we have found that heparanase activity was mainly located in gelatinase-containing tertiary granules. Using a specific antibody, the 96-kDa heparanase protein was further located in the gelatinase-rich subcellular fractions. Following immunoblotting and immunoprecipitation analysis in the distinct subcellular fractions, we also found co-localization of heparanase and Mo1 (CD11b/CD18), a leucocyte integrin involved in the attachment of neutrophils to the endothelium, in the fractions enriched in gelatinase-containing tertiary granules. Treatment of human neutrophils with tumour necrosis factor or granulocyte/macrophage colony-stimulating factor induced an increase in the CD11b/CD18 cell-surface expression, as well as the release of both gelatinase (matrix metalloproteinase-9) and heparanase, but not of other granule markers, indicating a major co-localization of gelatinase, heparanase and CD11b/CD18 in the same organelle. Furthermore, confocal laser scanning microscopy using specific antibodies against gelatinase and heparanase revealed a major co-localization of both enzymes in intracellular cytoplasmic granules. The major localization of heparanase and CD11b/CD18 in the gelatinase-containing tertiary granule supports the notion that mobilization of this organelle can regulate extravasation of human neutrophils.

Calpain expression in lymphoid cells. Increased mRNA and protein levels after cell activation

Although calpain is ubiquitously present in human tissues and is thought to play a role in demyelination, its activity is very low in resting normal lymphocytes. To determine the nature of calpain expression at the mRNA and protein levels in human lymphoid cells, we studied human T lymphocytic, B lymphocytic, and monocytic lines as well as peripheral blood mononuclear cells. Stimulation of cells with the phorbol ester phorbol myristate acetate and the calcium ionophore A23187 resulted in increased calpain mRNA and protein expression. Calpain mRNA expression is also increased in human T cells stimulated with anti-CD3. A dissociation between the increases of RNA and protein suggested that calpain could be released from the cells; the subsequent experiments showed its presence in the extracellular environment. 5,6-Dichloro-1b-D-ribofuranosylbenzimidazole, a reversible inhibitor of mRNA synthesis, reduced calpain mRNA levels by 50-67% and protein levels by 72-91%. Its removal resulted in resumption of both calpain mRNA and protein synthesis. Cycloheximide, a translational inhibitor, reduced calpain protein levels by 77-81% and calpain mRNA levels by 96% in activated THP-1 cells. Interferon-gamma induced calpain mRNA and protein in U-937 and THP-1 cells. Dexamethasone increased mRNA expression in THP-1 cells. Our results indicate that activation of lymphoid cells results in de novo synthesis and secretion of calpain.

Expression of the vaccinia virus genome: analysis and mapping of mRNAs encoded within the inverted terminal repetition

We have investigated the organization of transcriptional units within a 9000 bp segment of the terminally repeated region of the DNA genome of vaccinia virus, which uses its own enzyme system to synthesize mRNA within the cytoplasm of infected cells. RNA splicing, which has been demonstrated for DNA viruses that replicate within the nucleus of infected cells, does not appear to be involved in the formation of these first vaccinia virus mRNAs to be examined. Three immediate early mRNAs, approximately 1050, 600 and 1100 nucleotides long, were mapped between 3.21 and 4.24, 6.54 and 7.16, and 7.20 and 8.23 kb from the end of the genome, respectively. The direction of transcription was toward the end of the genome for the two larger mRNAs and in the opposite direction for the smallest one. Additional minor RNAs, which were larger in size, were mapped between and to the same DNA strand as the mRNAs of 1050 and 1100 nucleotides. No evidence for interrupted genes was obtained by nuclease S1 analysis after hybridization of RNA to labeled DNA. In addition, the 5' ends of the mRNAs, which were specifically labeled by in vitro capping, hybridized to DNA adjacent to the body of the message.

Genetic and biochemical normalization in female carriers of Duchenne muscular dystrophy: evidence for failure of dystrophin production in dystrophin-competent myonuclei

We studied 19 symptomatic female carriers of the Duchenne muscular dystrophy (DMD) gene. Most of these dystrophinopathy patients had had an erroneous or ambiguous diagnosis prior to dystrophin immunofluorescence testing. We assessed clinical severity by a standardized protocol, measured X-chromosome inactivation patterns in blood and muscle DNA, and quantitated the dystrophin protein content of muscle. We found that patients could be separated into two groups: those showing equal numbers of normal and mutant dystrophin genes in peripheral blood DNA ("random" X-inactivation), and those showing preferential use of the mutant dystrophin gene ("skewed" X-inactivation). In the random X-inactivation carriers, the clinical phenotype ranged from asymptomatic to mild disability, the dystrophin content of muscle was > 60% of normal, and there were only minor histopathologic changes. In the skewed X-inactivation patients, clinical manifestations ranged from mild to severe, but the patients with mild disease were young (5 to 10 years old). The low levels of dystrophin (< 30% on average) and the severe symptoms of the older patients suggested a poor prognosis for those with skewed X-inactivation, and they all showed morphologic changes of dystrophy. The random inactivation patients showed evidence of biochemical "normalization," with higher dystrophin content in muscle than predicted by the number of normal dystrophin genes. Seventy-nine percent of skewed X-inactivation patients (11/14) showed genetic "normalization," with proportionally more dystrophin-positive nuclei in muscle than in blood. In 65% of the skewed X-inactivation patients, dystrophin was not produced by dystrophin-positive nuclei; an average of 20% of myofiber nuclei were genetically dystrophin-positive but did not produce stable dystrophin. Biochemical normalization seems to be the main mechanism for rescue of fibers from dystrophin deficiency in the random X-inactivation patients. In the skewed X-inactivation patients, genetic normalization is active, but production failure of dystrophin by dystrophin-normal nuclei may counteract any effect of biochemical normalization. In the skewed X-inactivation patients, the remodeling of the muscle through cycles of degeneration and regeneration led to threefold increase in the number of dystrophin-competent nuclei in muscle myofibers (3.3 +/- 4.6), while dystrophin content was on the average 1.5-fold less then expected (-1.54 +/- 3.38). Our results permit more accurate prognistic assessment of isolated female dystrophinopathy patients and provide important data with which to estimate the potential effect of gene delivery (gene therapy) in DMD.

Abnormality in catalase import into peroxisomes leads to severe neurological disorder

Peroxisomal disorders are lethal inherited diseases caused by either defects in peroxisome assembly or dysfunction of single or multiple enzymatic function(s). The peroxisomal matrix proteins are targeted to peroxisomes via the interaction of peroxisomal targeting signal sequences 1 and 2 (PTS1 or PTS2) with their respective cytosolic receptors. We have studied human skin fibroblast cell lines that have multiple peroxisomal dysfunctions with normal packaging of PTS1 and PTS2 signal-containing proteins but lack catalase in peroxisomes. To understand the defect in targeting of catalase to peroxisomes and the loss of multiple enzyme activities, we transfected the mutant cells with normal catalase modified to contain either PTS1 or PTS2 signal sequence. We demonstrate the integrity of these pathways by targeting catalase into peroxisomes via PTS1 or PTS2 pathways. Furthermore, restoration of peroxisomal functions by targeting catalase-SKL protein (a catalase fused to the PTS1 sequence) to peroxisomes indicates that loss of multiple functions may be due to their inactivation by H2O2 or other oxygen species in these catalase-negative peroxisomes. In addition to enzyme activities, targeting of catalase-SKL chimera to peroxisomes also corrected the in situ levels of fatty acids and plasmalogens in these mutant cell lines. In normal fibroblasts treated with aminotriazole to inhibit catalase, we found that peroxisomal functions were inhibited to the level found in mutant cells, an observation that supports the conclusion that multiple peroxisomal enzyme defects in these patients are caused by H2O2 toxicity in catalase-negative peroxisomes. Moreover, targeting of catalase to peroxisomes via PTS1 and PTS2 pathways in these mutant cell lines suggests that there is another pathway for catalase import into peroxisomes and that an abnormality in this pathway manifests as a peroxisomal disease.

Lovastatin therapy for X-linked adrenoleukodystrophy: clinical and biochemical observations on 12 patients

X-linked adrenoleukodystrophy (X-ALD) is a progressive demyelinating disorder whose neurological signs and symptoms can manifest in childhood as cerebral ALD or in adulthood in the form of a progressive myelopathy (AMN). The consistent metabolic abnormality in all forms of X-ALD is an inherited defect in the peroxisomal beta-oxidation of very long chain (VLC) fatty acids (>C(22:0)) which may in turn lead to a neuroinflammatory process associated with demyelination of the cerebral white matter. The current treatment for X-ALD with Lorenzo's oil aims to lower the excessive quantities of VLC fatty acids that accumulate in the patients' plasma and tissues, but does not directly address the inflammatory process in X-ALD. We have previously demonstrated that lovastatin and other 3-HMG-CoA reductase inhibitors are capable of normalizing VLC fatty acid levels in primary skin fibroblasts derived from X-ALD patients. Lovastatin can block the induction of inducible nitric oxide synthase and proinflammatory cytokines in astrocytes, microglia, and macrophages in vitro. In a preliminary report, we demonstrated that lovastatin therapy can normalize VLC fatty acids in the plasma of patients with X-ALD. Here we report our clinical and biochemical observations on 12 patients with X-ALD who were treated with lovastatin for up to 12 months. Our results show that the high plasma levels of hexacosanoic acid (C(26:0)) showed a decline from pretreatment values within 1 to 3 months of starting therapy with 40 mg of lovastatin per day and stabilized at various levels during a period of observation up to 12 months. The percentage decline from pretreatment values varied and did not correlate with the type of ALD gene mutation (point mutation versus gene deletion). In 6 patients, in whom red cell membrane fatty acid composition was studied, a mean correction of 50% of the excess C(26:0) was observed after 6 months of therapy suggesting sustained benefit. In a few patients who discontinued lovastatin therapy plasma C(26:0) levels reverted to pretreatment values suggesting a cause and effect relationship between these events. Two patients dropped out of the study claiming no clinical benefit, 1 was withdrawn due to adverse effects, and an adult patient with cerebral involvement died during the study. A 10-year-old boy with severe cerebral involvement showed worsening of his neurological status. All patients with AMN remained neurologically stable or showed modest subjective improvement. All patients who did not have Addison's disease at the time of enrollment maintained normal adrenal function throughout the study. The implications of our findings for developing an effective therapy for X-ALD are discussed.

Visualization of an inverted terminal repetition in vaccinia virus DNA

An inverted terminal repetition was observed in DNA molecules extracted from vaccinia virus. The repeated sequence was visualized by (i) nicking the hairpin loops present of the ends of vaccinia virus DNA, (ii) separating the strands of DNA by alkali denaturation, (iii) allowing the single strands to self-anneal, and (iv) examining the DNA with an electron microscope. Single-stranded circular molecules, each of which contained a duplex projection (3.54 +/- 0.12 micron) representing the terminal repetition, readily formed. Similar size projections were also seen in heteroduplex structures formed by crosshybridization of the separated strands of the two terminal HindIII restriction fragments. Based on contour length measurements and the electrophoretic mobility of the isolated inverted terminal repetition, a molecular weight of approximately 6.9 X 10(6), equivalent to about 10,500 nucleotide base pairs, was estimated. Evidence was obtained from DNA-RNA hybridization studies that the terminal repetition is transcribed.

Inverted terminal repetition in vaccinia virus DNA encodes early mRNAs

Vaccinia virus DNA contains a long inverted terminal repetition of MW approximately 6.8 x 10(6). A fragment of MW 6.3 X 10(6) from this repetition has been cloned in coliphage lambda and used to isolate RNA from virus-infected cells. Electron microscopy indicates that early RNAs are transcribed from the repeated sequence and cell-free translation shows that the RNAs code for polypeptides.

Safety and efficacy of non-steroidal anti-inflammatory drugs to reduce ileus after colorectal surgery

BACKGROUND

Ileus is common after elective colorectal surgery, and is associated with increased adverse events and prolonged hospital stay. The aim was to assess the role of non-steroidal anti-inflammatory drugs (NSAIDs) for reducing ileus after surgery.

METHODS

A prospective multicentre cohort study was delivered by an international, student- and trainee-led collaborative group. Adult patients undergoing elective colorectal resection between January and April 2018 were included. The primary outcome was time to gastrointestinal recovery, measured using a composite measure of bowel function and tolerance to oral intake. The impact of NSAIDs was explored using Cox regression analyses, including the results of a centre-specific survey of compliance to enhanced recovery principles. Secondary safety outcomes included anastomotic leak rate and acute kidney injury.

RESULTS

A total of 4164 patients were included, with a median age of 68 (i.q.r. 57-75) years (54·9 per cent men). Some 1153 (27·7 per cent) received NSAIDs on postoperative days 1-3, of whom 1061 (92·0 per cent) received non-selective cyclo-oxygenase inhibitors. After adjustment for baseline differences, the mean time to gastrointestinal recovery did not differ significantly between patients who received NSAIDs and those who did not (4·6 versus 4·8 days; hazard ratio 1·04, 95 per cent c.i. 0·96 to 1·12; P = 0·360). There were no significant differences in anastomotic leak rate (5·4 versus 4·6 per cent; P = 0·349) or acute kidney injury (14·3 versus 13·8 per cent; P = 0·666) between the groups. Significantly fewer patients receiving NSAIDs required strong opioid analgesia (35·3 versus 56·7 per cent; P < 0·001).

CONCLUSION

NSAIDs did not reduce the time for gastrointestinal recovery after colorectal surgery, but they were safe and associated with reduced postoperative opioid requirement.

Bombesin and other growth factors activate cell proliferation in chick embryo otic vesicles in culture

The ability of the mitogenic peptide bombesin and other growth factors to trigger and support early development of the inner ear was studied on chick embryo otocysts in culture. The normal pattern of development was preserved in cultured otic vesicles in the presence of 20% fetal calf serum in the medium. Differentiation proceeded from stage 18 to 22 during the first 24 h and further to stage 24 in 48 h. Estimates of cell number and mitotic rates revealed a distinct period of proliferative growth which was maximum at the 24 h period of incubation. This was coincident with a high rate of DNA synthesis as measured by the acid-precipitable incorporation of [3H]thymidine. Development could be arrested by deprivation of serum during 24h. It could then be reactivated by readmission of serum to proceed with the normal pattern of morphological differentiation and cell proliferation. Bombesin (100 nM) was able to reactivate development in growth-arrested vesicles. Its effect was dose-dependent, saturable and potentiated by insulin (5 micrograms ml-1) which was ineffective if used alone. When associated with insulin, bombesin carried differentiation to stage 21 and stimulated mitotic activity above the level of serum as judged from estimates of cell number and [3H]thymidine uptake. EGF and PDGF were also effective in reinitiating development although their potency was smaller than bombesin. The reactivation by serum or bombesin was blocked by amiloride. The results show that (1) the otic vesicle can provide a useful model for studying the mechanisms that control proliferative growth and differentiation during normal development and (2) bombesin and other growth factors are able to activate growth in embryonic developing tissues.

The use of hypothermia: a role in the treatment of neonatal asphyxia?

Perinatal asphyxia remains one of the most devastating neurologic processes. Although the understanding of the pathophysiology after perinatal asphyxia is extensive, there are few therapeutic interventions available to prevent or even mitigate the devastating process that unfolds after injury. The search for a safe and efficacious therapy has prompted scientists and clinicians to consider various promising therapies. One such therapy is therapeutic hypothermia. On the basis of adult, pediatric, and animal research, there is increasing evidence to suggest that therapeutic hypothermia may be an effective intervention to lessen the secondary neuronal injury that ensues after a hypoxic-ischemic insult. In this article the historic and modern-day uses of therapeutic hypothermia are first reviewed. The pathophysiology of neonatal asphyxia is examined next, with emphasis on the changes that occur when therapeutic hypothermia is implemented. Potential side-effects of the therapy in the neonate and the debate over systemic vs selective hypothermia are discussed. Lastly, although hypothermia as a potential treatment modality for neonates with hypoxic-ischemic encephalopathy is supported by numerous studies, the need for well-designed multicenter trials with detailed patient entry criteria and therapeutic conditions is emphasized.

Pilot study with a glutamine-supplemented enteral formula in critically ill infants

Seriously ill infants often display protein-calorie malnutrition due to the metabolic demands of sepsis and respiratory failure. Glutamine has been classified as a conditionally essential amino acid, with special usefulness in critical patients. Immunomodulation, gut protection, and prevention of protein depletion are mentioned among its positive effects in such circumstances. With the intent of evaluating the tolerance and clinical impact of a glutamine supplement in seriously ill infants, a prospective randomized study was done with nine patients. Anthropometric and biochemical determinations were made, and length of stay in the intensive care unit (ICU), in the hospital, and under artificial ventilation, and septic morbidity and mortality were tabulated. Infants in the treatment group (n = 5) were enterally administered 0.3 g/kg of glutamine, whereas controls received 0.3 g/kg of casein during a standard period of five days. Septic complications occurred in 75% of the controls (3/4) versus 20% of the glutamine-treated group (1/5, p < or = 0.10), and two patients in the control group died of bacterial infections (50% vs. 0%, p < or = 0.10). Days in the ICU, in the hospital, and with ventilation numerically favored glutamine therapy, although without statistical significance. The supplements were usually well tolerated, and no patient required discontinuation of the program. The conclusion was that glutamine supplementation was safe and tended to be associated with less infectious morbidity and mortality in this high-risk population.

European Society of Coloproctology consensus on the surgical management of intestinal failure in adults

Intestinal failure (IF) is a debilitating condition of inadequate nutrition due to an anatomical and/or physiological deficit of the intestine. Surgical management of patients with acute and chronic IF requires expertise to deal with technical challenges and make correct decisions. Dedicated IF units have expertise in patient selection, operative risk assessment and multidisciplinary support such as nutritional input and interventional radiology, which dramatically improve the morbidity and mortality of this complex condition and can beneficially affect the continuing dependence on parenteral nutritional support. Currently there is little guidance to bridge the gap between general surgeons and specialist IF surgeons. Fifteen European experts took part in a consensus process to develop guidance to support surgeons in the management of patients with IF. Based on a systematic literature review, statements were prepared for a modified Delphi process. The evidence for each statement was graded using Oxford Centre for Evidence-Based Medicine Levels of Evidence. The current paper contains the statements reflecting the position and practice of leading European experts in IF encompassing the general definition of IF surgery and organization of an IF unit, strategies to prevent IF, management of acute IF, management of wound, fistula and stoma, rehabilitation, intestinal and abdominal reconstruction, criteria for referral to a specialist unit and intestinal transplantation.

Disruption of proteoglycans in neural tube fluid by beta-D-xyloside alters brain enlargement in chick embryos

Following neurulation, the anterior end of the neural tube undergoes a dramatic increase in size due mainly to the enlarging of the brain cavity. This cavity is filled with so-called neural tube fluid (NTF), whose positive pressure has been shown to play a key role in brain morphogenesis. This fluid contains a water-soluble matrix, rich in chondroitin sulfate (CS), which has been proposed as an osmotic regulator of NTF pressure genesis. The purpose of the present study is to observe the influence of CS on NTF osmolality and its relation to NTF hydrostatic pressure and brain expansion. NTF was obtained by means of microaspiration from the mesencephalic cavity of chick embryos. The osmolality of NTF between H.H. stages 20 and 29 was measured on the basis of its cryoscopic point. CS synthesis was disrupted by using beta-D-xyloside and the induced variations in brain volume were measured by means of morphometry. We also measured the variations in NTF osmolality, hydrostatic pressure, and the concentration of CS and sodium induced by means of beta-D-xyloside. Our data reveal that, at the earliest stages of development analyzed, variations in NTF osmolality show a characteristic pattern that coincides with the developmental changes in the previously described fluid pressure. Chick embryos treated with beta-D-xyloside, a chemical that disrupts CS synthesis, displayed a notable increase in brain volume but no other apparent developmental alterations. Morphometric analysis revealed that this increase was due to hyperenlargement of the brain cavity. Beta-D-xyloside brings about specific changes in the biochemical composition of NTF, which entails a large increase in CS concentration, mainly in the form of free chains, and in that of sodium. As a result, the fluid's osmolality and brain intraluminal pressure increased, which could account for the increase in size of the brain anlage. These data support the hypothesis that the intraluminal pressure involved in embryonic brain enlargement is directly dependent on NTF osmolality, and that the concentrations of CS and its associated microions could play a key role in the regulation of this process.

Involvement of sulfated proteoglycans in embryonic brain expansion at earliest stages of development in rat embryos

The expansive force generated by the positive pressure of the neural tube fluid confined inside the brain vesicles has been shown to be a key factor during the earliest stages of brain morphogenesis and development of chick embryos. In a previous study, we demonstrated the existence of an intracavity extracellular matrix rich in condroitin sulfate in this species, which could be involved in the regulation of the expansive process. In this report, scanning electron microscopy and immunohistochemistry show that, after neurulation, a similar extracellular matrix rich in chondroitin sulfate is present inside the brain vesicles of rat embryos during early enlargement of the brain anlage. In vitro treatment of rat embryos with beta-D-xyloside (a chemical compound which disrupts chondroitin sulfate synthesis) shows that changes in intralumen chondroitin sulfate concentration are accompanied by significant changes in brain anlage growth. These results support the hypothesis that intracerebral chondroitin sulfate plays a relevant role in the regulation of the expansive process of the brain anlage of rat embryos, and could represent a general mechanism in the early brain development of avian and mammalian embryos.

Chondroitin sulphate proteoglycan and embryonic brain enlargement in the chick

Previous studies of the early development of the neural tube have shown the existence of an intraneural fluid, which causes a positive pressure inside this primordium, and seems to play a key role in the early development of the central nervous system. In the present study we investigated the composition and synthesis of this intraneural fluid. By using a sequential method, which includes fixation with glutaraldehyde plus cetylpyridinium chloride, opening the neural cavity after critical point drying and scanning electron microscopy analysis, we found a water-soluble extracellular matrix that filled up the brain vesicles of chick embryos at the earliest stages of the neural tube. An ultrastructural study of the neural epithelium during these stages revealed the existence of a secretion process in the neural cells toward the apical side, the future neural cavity. An immunocytochemical study to assess the nature of the secreted material has shown that the intraneural matrix contains chondroitin sulphate proteoglycan, which appeared homogeneously distributed throughout the neural cavity. Our findings demonstrate that the intraneural liquid is a fluid of complex composition and includes chondroitin sulphate proteoglycan as an osmotically active molecule. This suggests a morphogenetic role for the proteoglycan during early brain enlargement. The neural ectoderm is a polarized epithelium from early developmental stages and secretes the intraneural matrix.

Prognostic factors for traumatic bowel injuries: killing time

BACKGROUND

Intestinal rupture/perforation after abdominal trauma is a rare complication, but it is related to significant morbidity and mortality. Our objective is to identify determinants of prognosis in patients surgically treated for a bowel injury (small bowel and colon) after abdominal trauma.

METHODS

The present study is a retrospective analysis of 102 patients seen at our hospital during a 10-year period in whom laparotomy for traumatic bowel injury was performed. Predictors for morbidity and mortality were assessed in univariate and multivariate analysis models.

RESULTS

Mean age at diagnosis was 40 years, and most patients were male. There was a slight preponderance of blunt abdominal trauma, and the most frequent mechanism of injury was motor vehicle accident. In 75% of patients there was a small bowel lesion, and the colon was affected in 47%. There was no statistical relation between stoma construction and mortality, but an increase in morbidity was ultimately dependent on the severity of the underlying trauma. The univariate determinants of mortality were the new injury severity score (NISS) and American Society of Anesthesiologists (ASA) scores, the presence of blunt trauma and multiple intestinal or extra-abdominal lesions, and the elapsed time to surgery. The occurrence of postoperative complications was related to all these factors, as well as to tachycardia, hypotension, and bleeding. In multivariate analysis ASA score (p = 0.015), NISS (p = 0.002), time to surgery (p = 0.007), and presence of colonic lesions (p = 0.02) were identified as independent prognostic factors for postoperative morbidity.

CONCLUSIONS

The only modifiable determinant of morbidity seems to be the time to surgery. Only an expeditious evaluation and diagnosis and prompt surgical intervention can improve the prognosis of these patients.