Atypical teratoid rhabdoid tumours (ATRTs)-a 21-year institutional experience.

PURPOSE: Atypical teratoid/rhabdoid tumours (ATRTs) are malignant embryonal tumours of childhood that affect the central nervous system (CNS). We aim to determine which factors, including patient age, extent of resection (EOR), presence of distal metastasis and use of adjuvant therapies, affect overall survival in children with atypical teratoid/rhabdoid tumours (ATRTs) treated at this single centre. METHODS: Retrospective cohort review of patients with histological diagnosis of ATRT treated over 21 years (1999-2020) was conducted. Data on demographics, tumour location, presence of metastasis, use of adjuvant therapy, extent of resection (EOR), complications, neurological outcome post-surgery, and overall survival were collected. Kaplan-Meier survival analysis was performed. RESULTS: A total of 45 children (mean age 2 years) underwent 64 operations. 25 patients were <1 year of age. Gross-total resection (GTR) pre-adjuvant therapy was achieved in 15, near-total resection (NTR) in 15, subtotal resection (STR) in 9, and biopsy in 6 children. Most children had good neurological outcomes post-operatively (28/45 with GOS 5). Fourteen patients survived longer than 4 years. Survival analysis showed a significant difference in median survival in favour of GTR and localised disease. There was no significant difference in median survival between patients <1 year vs >1 year of age (p=0.84). CONCLUSION: We find that presence of metastasis was an important factor in poor survival in patients with ATRT. GTR, where possible, may confer significant survival benefit in ATRT. Children aged <1 year appear to have performed as well as those >1 year and therefore should still be considered for radical surgery.

Intracranial pressure in patients with papilloedema.

OBJECTIVES: Papilloedema is a clinical manifestation of chronically raised intracranial pressure (ICP), often seen in idiopathic intracranial hypertension (IIH). However, the extent of intracranial hypertension required to produce papilloedema is not known. We compare ICP values in IIH patients who developed papilloedema and those who did not. We aim to identify a pathological ICP threshold predictive of the development of papilloedema in IIH patients. MATERIALS AND METHODS: Single-centre cohort of IIH patients (2006-2016) who underwent 24-hour ICP monitoring (ICPM) and ophthalmology assessments, prior to intervention. Papilloedema was graded according to the Frisén scale. An unpaired t-test compared 24-hour ICPM between papilloedema and no-papilloedema groups. Fisher's exact test was used to determine predictive value of ICP. RESULTS: Thirty-six patients with IIH (35 F: 1M), mean age 32.5 ± 9.49 years (mean ± SD) were included. Patients with papilloedema had a mean median 24-hour ICP of 10.4 ± 5.32 mm Hg (n = 25), significantly higher than the group without papilloedema 6.31 ± 3.30 mm Hg (n = 11) (P < .05). The papilloedema group were exposed to higher pressures (10 mm Hg) for 30 minutes or more. Using 24-hour median ICP of 10 mm Hg as a minimum cut-off predictive value gives a specificity = 91%, sensitivity = 48%, PPV = 92% and NPV = 44% of detecting papilloedema. CONCLUSIONS: A 24-hour ICP of 10 mmHg or more is a good predictor for papilloedema and reflects a pathological threshold. The range varied widely suggesting papilloedema can occur at even lower pressures. These results are consistent with emerging evidence suggest that pathologically "high" 24 hours ICP is lower than previously quoted.

Elective ICP monitoring: how long is long enough?

BACKGROUND: Intracranial pressure monitoring is commonly undertaken to assess and manage acute patients following head injury. However, ICP monitoring can also be a useful diagnostic tool in the management of CSF dynamics in elective patients. To date, there is little published research to suggest how long these elective patients require ICP monitoring in order to gain an accurate picture of a patient's ICP dynamics. At the author's institution, a minimum of 48-h data collection is currently undertaken in patients with a suspected ICP abnormality. METHODS: A retrospective audit was undertaken comparing overall median ICP and overall median pulse amplitude data at three time points, 24 h, 48 h and total time analysed (if longer than 48 h). Paired T-test was used to assess if there were statistically significant differences between 24-h versus 48-h monitoring and total duration of monitoring. All patients admitted over a 6-month period for ICPM who met the inclusion/exclusion criteria were included. RESULTS: Eighteen patients met the criteria. Median age was 45.8 years, range 22-83 years, 12 female and 6 male. No complications were experienced as a result of ICPM. Diagnosis included NPH, IIH, suspected shunt malfunction and Chiari malformation. The results demonstrated that there is no statistical difference between 24 h and 48 h or longer for both overall median ICP and pulse amplitude. CONCLUSION: The results of this study demonstrate that ICP monitoring of elective adult patients using a Spiegelberg intraparenchymal bolt for 24 h gives an accurate picture of a patient's ICP dynamics compared with longer periods of monitoring.

The spatial distribution of the exocyst and actin cortical patches is sufficient to organize hyphal tip growth.

In the hyphal tip of Candida albicans we have made detailed quantitative measurements of (i) exocyst components, (ii) Rho1, the regulatory subunit of (1,3)-ß-glucan synthase, (iii) Rom2, the specialized guanine-nucleotide exchange factor (GEF) of Rho1, and (iv) actin cortical patches, the sites of endocytosis. We use the resulting data to construct and test a quantitative 3-dimensional model of fungal hyphal growth based on the proposition that vesicles fuse with the hyphal tip at a rate determined by the local density of exocyst components. Enzymes such as (1,3)-ß-glucan synthase thus embedded in the plasma membrane continue to synthesize the cell wall until they are removed by endocytosis. The model successfully predicts the shape and dimensions of the hyphae, provided that endocytosis acts to remove cell wall-synthesizing enzymes at the subapical bands of actin patches. Moreover, a key prediction of the model is that the distribution of the synthase is substantially broader than the area occupied by the exocyst. This prediction is borne out by our quantitative measurements. Thus, although the model highlights detailed issues that require further investigation, in general terms the pattern of tip growth of fungal hyphae can be satisfactorily explained by a simple but quantitative model rooted within the known molecular processes of polarized growth. Moreover, the methodology can be readily adapted to model other forms of polarized growth, such as that which occurs in plant pollen tubes.

The virulence factor PEB4 (Cj0596) and the periplasmic protein Cj1289 are two structurally related SurA-like chaperones in the human pathogen Campylobacter jejuni.

The PEB4 protein is an antigenic virulence factor implicated in host cell adhesion, invasion, and colonization in the food-borne pathogen Campylobacter jejuni. peb4 mutants have defects in outer membrane protein assembly and PEB4 is thought to act as a periplasmic chaperone. The crystallographic structure of PEB4 at 2.2-Å resolution reveals a dimer with distinct SurA-like chaperone and peptidyl-prolyl cis/trans isomerase (PPIase) domains encasing a large central cavity. Unlike SurA, the chaperone domain is formed by interlocking helices from each monomer, creating a domain-swapped architecture. PEB4 stimulated the rate of proline isomerization limited refolding of denatured RNase T(1) in a juglone-sensitive manner, consistent with parvulin-like PPIase domains. Refolding and aggregation of denatured rhodanese was significantly retarded in the presence of PEB4 or of an engineered variant specifically lacking the PPIase domain, suggesting the chaperone domain possesses a holdase activity. Using bioinformatics approaches, we identified two other SurA-like proteins (Cj1289 and Cj0694) in C. jejuni. The 2.3-Å structure of Cj1289 does not have the domain-swapped architecture of PEB4 and thus more resembles SurA. Purified Cj1289 also enhanced RNase T(1) refolding, although poorly compared with PEB4, but did not retard the refolding of denatured rhodanese. Structurally, Cj1289 is the most similar protein to SurA in C. jejuni, whereas PEB4 has most structural similarity to the Par27 protein of Bordetella pertussis. Our analysis predicts that Cj0694 is equivalent to the membrane-anchored chaperone PpiD. These results provide the first structural insights into the periplasmic assembly of outer membrane proteins in C. jejuni.

When simple sequence comparison fails: the cryptic case of the shared domains of the bacterial replication initiation proteins DnaB and DnaD.

DnaD and DnaB are essential DNA-replication-initiation proteins in low-G+C content Gram-positive bacteria. Here we use sensitive Hidden Markov Model-based techniques to show that the DnaB and DnaD proteins share a common structure that is evident across all their structural domains, termed DDBH1 and DDBH2 (DnaD DnaB Homology 1 and 2). Despite strong sequence divergence, many of the DNA-binding and oligomerization properties of these domains have been conserved. Although eluding simple sequence comparisons, the DDBH2 domains share the only strong sequence motif; an extremely highly conserved YxxxIxxxW sequence that contributes to DNA binding. Sequence alignments of DnaD alone fail to identify another key part of the DNA-binding module, since it includes a poorly conserved sequence, a solvent-exposed and somewhat unstable helix and a mobile segment. We show by NMR, in vitro mutagenesis and in vivo complementation experiments that the DNA-binding module of Bacillus subtilis DnaD comprises the YxxxIxxxW motif, the unstable helix and a portion of the mobile region, the latter two being essential for viability. These structural insights lead us to a re-evaluation of the oligomerization and DNA-binding properties of the DnaD and DnaB proteins.

Early versus late surgery for traumatic spinal cord injury: the results of a prospective Canadian cohort study.

STUDY DESIGN: A multicenter Canadian cohort study. OBJECTIVES: The objective of this study is to evaluate the impact of early versus late surgical decompression on motor neurological recovery after traumatic spinal cord injury (SCI). SETTING: Canadian acute care and SCI rehabilitation facilities. METHODS: A prospective cohort study of patients within the Ontario Spinal Cord Injury Registry program was performed. We considered SCI patients with an admission American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade of A through D, with magnetic resonance imaging-confirmed spinal cord compression. Grouped analysis was performed comparing the cohort of patients who received early surgery (<24 h after SCI) to those receiving delayed surgery (<24 h after SCI). The primary outcome was the change in ASIA motor score (AMS) occurring between hospital admission and rehabilitation discharge. RESULTS: A total of 35 (41.7%) patients underwent early surgery and 49 (58.3%) underwent late surgery. At admission, there was a greater proportion of patients within the early surgery group with more severe AIS grade A injuries. Of the 55 patients with neurological exam available at rehabilitation discharge, a greater proportion had at least a two-grade AIS improvement in the early-surgery group (P=0.01). The mean improvement in AMS at rehabilitation discharge was 20 points amongst early-surgery patients and 15 points amongst late-surgery patients (P=0.46). In the analysis investigating AMS improvement, adjusted for preoperative status and neurological level, there was a positive effect estimate for early surgical therapy that was statistically significant (P=0.01). CONCLUSION: The results here add weight to the growing body of literature, which supports the principle of early intervention in the setting of spinal trauma and SCI.

A new grading for easy and concise description of functional status after spinal cord lesions.

BACKGROUND: Disability scales do not enable the transmission of concise, meaningful and daily function description for clinical purposes. STUDY DESIGN: Cross-sectional statistical analysis of 328 patients' Spinal Cord Independence Measure (SCIM) III item scores (SIS). OBJECTIVE: To develop a concise and clinically interpretable data-based characterization of daily task accomplishment for patients with spinal cord lesions (SCLs). SETTING: Multi-center study at 13 spinal units in 6 countries. METHODS: Patients were grouped into clusters characterized by smaller differences between the patients' SIS within the clusters than between their centers, using the k-medoides algorithm. The number of clusters (k) was chosen according to the percent of SIS variation they explained and the clinical distinction between them. RESULTS: Analysis showed that k=8 SIS clusters offer a good description of the patient population. The eight functional clusters were designated as A-H, each cluster (grade) representing a combination of task accomplishments. Higher grades were usually (but not always) associated with patients implementing more difficult tasks. Throughout rehabilitation, the patients' functional grade improved and the distribution of patients with similar functional grades within the total SCIM III score deciles remained stable. CONCLUSIONS: A new classification based on SIS clusters enables a concise description of overall functioning and task accomplishment distribution in patients with SCL. A software tool is used to identify the patients' functional grade. Findings support the stability and utility of the grades for characterizing the patients' functional status.

'Valve-stabilised' rhinospirometry can predict the benefit of septal surgery: a pre- and post-operative correlation study.

Septoplasty is a procedure often associated with high levels of patient dissatisfaction post-operatively. This study examined whether rhinospirometry and a modified 'valve-stabilised' technique could pre-operatively predict the outcome of septal surgery and therefore have a role as an objective tool for selection of patients suffering from nasal obstruction due to septal deformity for the procedure of septoplasty. A prospective study was performed of patients attending Singleton Hospital, Swansea, for surgical treatment of nasal obstruction due to septal deformity. Participants were asked to undertake decongested visual analogue scoring (VAS) and rhinospirometric assessment of their nasal obstruction in both normal 'resting' and 'valve-stabilised' nasal positioning. These investigations were undertaken on the day of surgery and 6 weeks post-operatively. Results were converted into nasal partition ratio scores and were assessed statistically for difference, correlation and accuracy. A total of 29 individual participants were included in the study. Septal surgery produced a statistically significant improvement in nasal airflow symmetry in the normal 'resting' nasal position using rhinospirometry (Wilcoxon ranked p > 0.5). This difference was not seen between evaluations in 'valve-stabilised' position (Wilcoxon p < 0.001). No statistical difference was evident between pre-operative 'valve-stabilised' testing and post-operative 'resting position'. The finding was also apparent on VAS nasal assessment. Correlation studies showed a strong relationship between pre-operative 'valve-stabilised' and post-operative 'resting' rhinospirometry results (Spearman's rho = 0. 586, p < 0.002). The strength of this relationship between VAS assessments was less pronounced (Spearman's rho = 0.386 p = 0.07). 'Valve-stabilised' rhinospirometry and VAS appear to be useful pre-operatively to predict the outcome of septal surgery, in terms of airflow symmetry, for nasal obstruction due to septal deformity, with pre-operative 'valve-stabilised' results correlating well with the post-operative standard 'resting' outcomes. Valve-stabilised rhinospirometry may have a role in pre-operatively predicting of likely post-operative patient satisfaction, although further studies are required in this area.

Acute Lower Extremity Fracture Management in Chronic Spinal Cord Injury: 2022 Delphi Consensus Recommendations.

Our objective was to develop a clinical practice guideline (CPG) for the treatment of acute lower extremity fractures in persons with a chronic spinal cord injury (SCI). Methods: Information from a previous systematic review that addressed lower extremity fracture care in persons with an SCI as well as information from interviews of physical and occupational therapists, searches of the literature, and expert opinion were used to develop this CPG. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system was used to determine the quality of evidence and the strength of the recommendations. An overall GRADE quality rating was applied to the evidence. Conclusions: Individuals with a chronic SCI who sustain an acute lower extremity fracture should be provided with education regarding the risks and benefits of operative and nonoperative management, and shared decision-making for acute fracture management should be used. Nonoperative management historically has been the default preference; however, with the advent of greater patient independence, improved surgical techniques, and advanced therapeutics and rehabilitation, increased use of surgical management should be considered. Physical therapists, kinesiotherapists, and/or occupational therapists should assess equipment needs, skills training, and caregiver assistance due to changes in mobility resulting from a lower extremity fracture. Therapists should be involved in fracture management as soon as possible following fracture identification. Pressure injuries, compartment syndrome, heterotopic ossification, nonunion, malunion, thromboembolism, pain, and autonomic dysreflexia are fracture-related complications that clinicians caring for patients who have an SCI and a lower extremity fracture may encounter. Strategies for their treatment are discussed. The underlying goal is to return the patient as closely as possible to their pre-fracture functional level with operative or nonoperative management.

Distant cousins: genomic and sequence diversity within the BPI fold-containing (BPIF)/PLUNC protein family.

PLUNC (palate, lung and nasal epithelium clone) proteins make up the largest branch of the BPI (bactericidal/permeability-increasing protein)/LBP (lipopolysaccharide-binding protein) family of lipid-transfer proteins. PLUNCs make up one of the most rapidly evolving mammalian protein families and exhibit low levels of sequence similarity coupled with multiple examples of species-specific gene acquisition and gene loss. Vertebrate genomes contain multiple examples of genes that do not meet our original definition of what is required to be a member of the PLUNC family, namely conservation of exon numbers/sizes, overall protein size, genomic location and the presence of a conserved disulfide bond. This suggests that evolutionary forces have continued to act on the structure of this conserved domain in what are likely to be functionally important ways.

Systematic nomenclature for the PLUNC/PSP/BSP30/SMGB proteins as a subfamily of the BPI fold-containing superfamily.

We present the BPIFAn/BPIFBn systematic nomenclature for the PLUNC (palate lung and nasal epithelium clone)/PSP (parotid secretory protein)/BSP30 (bovine salivary protein 30)/SMGB (submandibular gland protein B) family of proteins, based on an adaptation of the SPLUNCn (short PLUNCn)/LPLUNCn (large PLUNCn) nomenclature. The nomenclature is applied to a set of 102 sequences which we believe represent the current reliable data for BPIFA/BPIFB proteins across all species, including marsupials and birds. The nomenclature will be implemented by the HGNC (HUGO Gene Nomenclature Committee).

Expected spinal cord independence measure, third version, scores for various neurological levels after complete spinal cord lesions.

STUDY DESIGN: Multicenter international cohort study. OBJECTIVE: The objective of this study was to establish target values for Spinal Cord Independence Measure (SCIM) III scoring in rehabilitation for clinically complete spinal cord lesion (SCL) neurological levels. SETTING: In total, 13 spinal cord units in six countries from North America, Europe and the Middle East were taken. METHODS: Total SCIM III scores and gain at discharge from rehabilitation were calculated for SCL levels in 128 patients with American Spinal Injury Association Impairment Scale (AIS) grade A on admission to rehabilitation. RESULTS: Median, quartiles, mean and s.d., values of discharge SCIM III scores and SCIM III gain for the various SCL levels are presented. Total SCIM III scores and gain were significantly correlated with the SCL level (r=0.730, r=0.579, P<0.001). CONCLUSIONS: Calculated discharge SCIM III scores can be used as target values for functional achievements at various neurological levels in patients after AIS A SCL. They are generally, but not always, inversely correlated with SCL level.

SCIM III is reliable and valid in a separate analysis for traumatic spinal cord lesions.

STUDY DESIGN: A multi-center international cohort study. OBJECTIVE: To evaluate the reliability and validity of the third version of the Spinal Cord Independence Measure (SCIM III), separately for patients with traumatic spinal cord lesions (SCLs). SETTING: A total of 13 spinal cord units in six countries from North America, Europe and the Middle-East. METHODS: SCIM III and Functional Independence Measure (FIM) were assessed for 261 patients with traumatic SCLs, on admission to rehabilitation and before discharge, by two raters. Conventional statistical measures were used to evaluate the SCIM III reliability and validity. RESULTS: In almost all SCIM III tasks, the total agreement between the paired raters was >80%. The κ coefficients were all >0.6 and statistically significant. Pearson's coefficients of the correlations between the paired raters were >0.9, the mean differences between raters were nonsignificant and the intraclass correlation coefficients (ICCs) were ≥ 0.95. Cronbach's α values for the entire SCIM III scale were 0.833-0.835. FIM and SCIM III total scores were correlated (r=0.84, P<0.001). SCIM III was more responsive to changes than FIM. In all subscales, SCIM III identified more changes in function than FIM, and in 3 of the 4 subscales, differences in responsiveness were statistically significant (P<0.02). CONCLUSION: The results confirm the reliability and validity of SCIM III for patients with traumatic SCLs in a number of countries.

The accuracy and reproducibility of rhinospirometry in detecting flow asymmetry in a nasal cavity model.

The objective of this study is to investigate the appropriateness of the NV1 rhinospirometer in the assessment of asymmetrical nasal airflow using a nasal cavity model. The Study is a laboratory-based basic-science study using an artificial model of nasal airflow. It is conducted in Medical Physics Department, Singleton Hospital, Swansea, Wales. A nasal cavity model was created with a series of parallel flow symmetry/asymmetries that were each assessed using standard flow volume measurements. The results were converted into Nasal Partition Ratios (NPRs) for each trial scenario and were examined against a mathematically calculated NPR derived using Pouseille's law. Experimental scenario results were assessed for correlation, accuracy and precision against the mathematically derived result. In this study 300 individual test scenarios were completed using 2 different flow volumes and 15 different symmetry/asymmetry combinations. Correlation of the attained results against the mathematically derived figure gave a very strong correlation, using Spearman's Rho = 0.975. Accuracy was excellent within one Standard deviation of the expected results. It was concluded that the NV1 rhinospirometer is an accurate and precise objective marker of airflow symmetry in the nasal cavity model giving strong correlation, accuracy, precision and reproducibility. The rhinospirometer, as a precision tool, has displayed potential to become an effective objective marker of nasal airflow in the assessment of nasal obstruction; however, clinical trials are required to examine whether the accurate results of this laboratory study are transferable to clinical practice.

Dimerization of protein G B1 domain at low pH: a conformational switch caused by loss of a single hydrogen bond.

A number of signals in the NMR spectrum of the B1 domain of staphylococcal protein G (GB1) show a chemical shift dependence on the concentration of the protein at pH 3 but not at neutral pH, implying the existence of self-association at low pH. NMR backbone relaxation experiments show that GB1 undergoes a slow conformational exchange at pH 3, which is not seen at higher pH. Analysis of relaxation dispersion experiments yields a self-association constant of 50 mM, and shows that (15)N chemical shift changes in the dimer interface are up to 3 ppm. The shift changes measured from concentration-dependent HSQC spectra and from relaxation dispersion show good consistency. Measurements of chemical shifts as a function of pH show that a hydrogen bond between the sidechains of Asp44 and Gln40 is broken when Asp44 is protonated, and that loss of this hydrogen bond leads to the breaking of the (i, i + 4) backbone helical hydrogen bond from Asp44 HN to Gln40 O, and therefore to a loss of two residues from the C-terminal end of the helix. This weakens the helix structure and facilitates the loss of further helical structure thus permitting dimerization, which is suggested to occur in the same way as observed for the A42F mutant of GB1 (Jee et al., Proteins 2007;71:1420-1431), by formation of an antiparallel beta-sheet between the edge strands 2 in two monomers. The monomer/dimer ratio is thus a finely balanced equilibrium even in the wild type protein.

A common neonatal image phenotype predicts adverse neurodevelopmental outcome in children born preterm.

Diffuse white matter injury is common in preterm infants and is a candidate substrate for later cognitive impairment. This injury pattern is associated with morphological changes in deep grey nuclei, the localization of which is uncertain. We test the hypotheses that diffuse white matter injury is associated with discrete focal tissue loss, and that this image phenotype is associated with impairment at 2years. We acquired magnetic resonance images from 80 preterm infants at term equivalent (mean gestational age 29(+6)weeks) and 20 control infants (mean GA 39(+2)weeks). Diffuse white matter injury was defined by abnormal apparent diffusion coefficient values in one or more white matter region (frontal, central or posterior white matter at the level of the centrum semiovale), and morphological difference between groups was calculated from 3D images using deformation based morphometry. Neurodevelopmental assessments were obtained from preterm infants at a mean chronological age of 27.5months, and from controls at a mean age of 31.1months. We identified a common image phenotype in 66 of 80 preterm infants at term equivalent comprising: diffuse white matter injury; and tissue volume reduction in the dorsomedial nucleus of the thalamus, the globus pallidus, periventricular white matter, the corona radiata and within the central region of the centrum semiovale (t=4.42 p<0.001 false discovery rate corrected). The abnormal image phenotype is associated with reduced median developmental quotient (DQ) at 2years (DQ=92) compared with control infants (DQ=112), p<0.001. These findings indicate that specific neural systems are susceptible to maldevelopment after preterm birth, and suggest that neonatal image phenotype may serve as a useful biomarker for studying mechanisms of injury and the effect of putative therapeutic interventions.

Automated protein structure calculation from NMR data.

Current software is almost at the stage to permit completely automatic structure determination of small proteins of <15 kDa, from NMR spectra to structure validation with minimal user interaction. This goal is welcome, as it makes structure calculation more objective and therefore more easily validated, without any loss in the quality of the structures generated. Moreover, it releases expert spectroscopists to carry out research that cannot be automated. It should not take much further effort to extend automation to ca 20 kDa. However, there are technological barriers to further automation, of which the biggest are identified as: routines for peak picking; adoption and sharing of a common framework for structure calculation, including the assembly of an automated and trusted package for structure validation; and sample preparation, particularly for larger proteins. These barriers should be the main target for development of methodology for protein structure determination, particularly by structural genomics consortia.

Reversible conversion of monomeric human prion protein between native and fibrilogenic conformations.

Prion propagation involves the conversion of cellular prion protein (PrPC) into a disease-specific isomer, PrPSc, shifting from a predominantly alpha-helical to beta-sheet structure. Here, conditions were established in which recombinant human PrP could switch between the native alpha conformation, characteristic of PrPC, and a compact, highly soluble, monomeric form rich in beta structure. The soluble beta form (beta-PrP) exhibited partial resistance to proteinase K digestion, characteristic of PrPSc, and was a direct precursor of fibrillar structures closely similar to those isolated from diseased brains. The conversion of PrPC to beta-PrP in suitable cellular compartments, and its subsequent stabilization by intermolecular association, provide a molecular mechanism for prion propagation.

Crystallization and preliminary X-ray analysis of recombinant Glomerella cingulata cutinase.

Cutinase catalyzes the hydrolysis of water-soluble esters and long-chain triglycerides and belongs to the family of serine hydrolases. The enzyme is thought to represent an evolutionary link between the esterase and lipase families and has potential applications in a wide range of industrial hydrolytic processes, for which an understanding of the molecular basis of its substrate specificity is critical. Glomerella cingulata cutinase has been cloned and the protein has been overexpressed in Escherichia coli, purified and subsequently crystallized in a wide range of different crystal forms in the presence and absence of inhibitors. The best crystals are those of the apo cutinase, which diffract to beyond 1.6 A resolution and belong to space group P4(1)2(1)2 or P4(3)2(1)2. Crystals of cutinase with the inhibitors PETFP or E600 belong to space groups P2(1)2(1)2(1) and P2(1), respectively, and diffract to approximately 2.5 A resolution. All of the crystals are suitable for structural studies, which are currently ongoing.