Custom cranioplasty using stereolithography and acrylic.

Numerous methods of cranioplasty have been described. Customization and prefabrication have been reported to reduce operating time and improve cosmesis. An original technique for the manufacture of customized cranioplastic implants has been developed and tested in 30 patients.Thirty patients requiring cranioplasties were selected. Data acquired from computed tomography (CT) were used to manufacture exact plastic replicas (biomodels) of craniotomy defects and master cranioplastic implants using the rapid prototyping technology of stereolithography (SL). The three-dimensional (3D) imaging techniques of mirroring and interpolation were used to extrapolate on existing anatomy to design the master implants. The master implants were hand finished to fit the defect in the corresponding cranial biomodel exactly and were then used to create a cavity mould. The mould was used to cast thermally polymerised custom acrylic implants. The surgeons reported that the customized implants reduced operating time, afforded excellent cosmesis and were cost effective. The patients reported that the opportunity to see the biomodel and implant preoperatively improved their understanding of the procedure. Two complications were noted, one infection and one implant required significant trimming. The simultaneous manufacture of the master implant (male) and biomodel (female) components from SL allowed custom accurate implants to be manufactured. Disadvantages identified were the time required for computer manipulations of the CT data (up to 2 h), difficulty in assessing the accuracy of the computer generated master as a 3D rendering, the potential for SL parts to warp, manufacturing time (minimum 2 days) and the cost of approximately $1300 US per case ($1000 for the SL biomodel and $300 for the acrylic casting).

A method for the resection of cranial tumours and skull reconstruction.

A new technique for the resection of cranial tumours and subsequent reconstruction using stereolithographic (SL) biomodelling and customized cranioplastic implants has been developed. The technique is based on a custom model of the tumour and surrounding skull from which the resection of the tumour and shape of the cranioplasty can be determined. A patient with a hyperostotic fronto-orbital meningioma was selected. CT was performed and SL biomodels manufactured. The surgeon marked the resection margin on the biomodel and a customized resection template was fashioned. The tumour was then resected from the biomodel and a customized acrylic implant was manufactured to reconstruct the defect. At surgery the tumour was exposed in a routine fashion and the template used to mark the resection margin. Once resected, the defect was reconstructed with the custom cranioplastic implant. The technique facilitated accurate surgical resection of the tumour and subsequent reconstruction. The surgeon reported several advantages of the technique including increased confidence, reduced operating time (at least 1 h), excellent cosmetic results, accuracy, and simplicity. The patient reported that the opportunity to see the biomodel, template and implant improved her understanding of the procedure.

Cerebrovascular biomodelling: a technical note.

BACKGROUND: Recently computed tomographic angiography (CTA) and MR angiography (MRA) have been used to image cerebrovascular structures. Although CTA and MRA are accurate and sensitive imaging modalities, limitations have been identified in relation to image interpretation. Stereolithographic (SL) biomodelling is a new technology that allows three-dimensional (3D) CT and MR data to be used to accurately manufacture solid plastic replicas of anatomical structures. A prospective trial of SL biomodelling in cerebrovascular surgery has been performed to investigate the feasibility and clinical utility of this new display medium. METHODS: Fifteen patients with cerebral aneurysms and 1 patient with a cerebral arteriovenous malformation (AVM) were selected. 3D CT and/or MR angiograms were acquired and 19 solid anatomical biomodels manufactured using the rapid prototyping technology of stereolithography. The biomodels were used for patient education, diagnosis, operative planning and surgical navigation. RESULTS: The biomodels replicated the CTA and MRA source data. The accuracy of one biomodel was verified by comparison with a post mortem specimen, which corresponded exactly in the x and y planes but differed by 2 mm in the z plane. The ability to closely study an overview of complex cerebrovascular anatomy from any perspective on a solid biomodel was reported to enhance the surgeon's understanding, particularly when conventional images were equivocal. Cerebrovascular biomodels were found to be useful when positioning the patient's head for surgery, for selecting the best aneurysm clip and for the simulation of clipping. Patient informed consent was anecdotally improved. Disadvantages of the technology were the cost and manufacturing time. CONCLUSIONS: Cerebrovascular biomodelling may have utility in complex cases or when the standard imaging is felt to be equivocal.

Biomodel-guided stereotaxy.

OBJECTIVES: To simplify the practice of stereotactic surgery by using an original method, apparatus, and solid anatomic replica for trajectory planning and to validate the method and apparatus in a laboratory and clinical trial. METHODS: The patient is marked with fiducials and scanned by using computed tomography or magnetic resonance imaging. The three-dimensional data are converted to a format acceptable to stereolithography. Stereolithography uses a laser to polymerize photosensitive resin into a solid plastic model (biomodel). Stereolithography can replicate blood vessels, soft tissue, tumor, and bone accurately (<0.8 mm). A stereotactic apparatus is referenced to fiducials replicated in the biomodel. The trajectory for the intervention is determined and saved. The apparatus is attached to the patient fiducials, and the intervention is replicated. RESULTS: Three types of apparatus (template, Brown-Roberts-Wells frame, and D'Urso frame) were tested on phantoms and patients requiring the excision/biopsy of tumors. The localization errors determined from the phantom studies were template, 0.82 mm; Brown-Roberts-Wells frame, 1.17 mm; and D'Urso frame, 0.89 mm. The surgeons reported that clinical use of the template and D'Urso frame was accurate and ergonomic. The Brown-Roberts-Wells frame was more difficult to use and somewhat inaccurate. CONCLUSION: Biomodel-guided stereotaxy has significant advantages. It is performed quickly; it is based on simple, intuitive methodology; it enhances visualization of anatomy and trajectory planning; it enhances patient understanding; it uses inexpensive equipment; it does not require rigid head fixation; and it has greater versatility than known techniques. Disadvantages are biomodel cost and a manufacturing time of 12 to 24 hours.

Inhibition of rotavirus infection in vitro and in vivo by a synthetic peptide from VP4.

A synthetic peptide corresponding to bovine rotavirus C486 (BRV) VP4 amino acid sequence 232-255 (VP4-peptide) was studied with the objective of defining the origin of the protective immune response reported previously by Ijaz et al. (J. Virol. 1991, 65, 3106-3113). Pretreatment of MA-104 cells with the VP4-peptide before infection with rotavirus prevented both the attachment of 35S-labelled virus and plaque formation in vitro. In vivo studies using a murine rotavirus model demonstrated that intragastric administration of VP4-peptide protected subjects from challenge with virulent rotavirus. These results clearly indicate the importance of this epitope in virus-cell interactions and their potential as a rotavirus vaccine candidate.

Characterization of the interaction between VP8 of bovine rotavirus C486 and cellular components on MA-104 cells and erythrocytes.

Rotavirus VP8*, the N-terminal trypsin cleavage product of VP4, has been shown to bind to MA-104 cells and human O type erythrocytes. To examine whether bacterially expressed VP8* binds to cellular components of MA-104 cells, the VP8* (aa 1-247) was expressed in E. coli and radiolabelled with 35S-methionine. The radiolabelled rVP8* was immunoprecipitated with antiserum to bovine rotavirus C486 (BRV). The rVP8* was found to bind to MA-104 cells and its binding was competed by BRV. To study the interaction between VP8* and receptors of erythrocytes, hemagglutination (HA) and hemagglutination inhibition (HI) assays were carried out using solubilized rVP8*. rVP8* showed HA which could be inhibited by antiserum to BRV. This interaction was also inhibited by gangliosides, demonstrating a sialic acid dependent interaction. To study the contribution of the C-terminal region of VP8* to HA, a number of approaches were used. First, a peptide spanning aa 230-247 was synthesized and antisera was raised against the peptide to see whether it could inhibit HA of rVP8*. Second, a truncated form of VP8* (tVP8*: aa 1-229) was expressed to examine its hemagglutinating activity. Third, the dimerization of rVP8* and tVP8* was compared by Western-blotting following electrophoresis using native SDS-PAGE. The results indicated that antibody to aa 230-247 inhibits hemagglutination by preventing dimerization of VP8* which in turn allows the molecule to cause HA. To characterize the interaction between the HA domain and sialic acid receptors, erythrocytes were treated with sialidases of different specificities. Arthrobacter ureafaciens, Clostridium perfringens and alpha 2-8 linkage-specific neuraminidase destroyed the ability of sialic acid of erythrocytes to interact with rVP8*, indicating that bovine rotavirus C486 binding requires an alpha 2-8 linkage but acetylation of the sialic acid is not necessary.

beta-(1-->3, 1-->4) oat glucan enhances resistance to Eimeria vermiformis infection in immunosuppressed mice.

The effect of intragastrically or parenterally administered beta-glucan, extracted from oats, on the enhancement of disease resistance to Eimeria vermiformis was studied in C57BL/6 mice. Groups of mice were immunosuppressed with dexamethasone (DXM), infected with oocysts of E. vermiformis and treated with oat beta-glucan by the intragastric (i.g.) or subcutaneous (s.c.) routes. Faecal oocyst shedding was reduced in the beta-glucan-treated groups compared to the non-treated group. Immunosuppressed mice which received no beta-glucan treatment showed more severe clinical signs of the disease and a 50% mortality, while minimal clinical signs and no mortality were recorded in the beta-glucan-treated groups. Total IgG, IgG1, IgG2a, IgM and IgA immunoglobulins in the serum of beta-glucan-treated groups were overall higher than those in the non-treated group. Specific IgG anti-sporozoite and merozoite immunoglobulins in serum were significantly higher in the beta-glucan-treated groups than in the non-treated animals. No significant differences were found in the levels of intestinal IgA anti-sporozoite and anti-merozoite immunoglobulins. IFN-gamma- and IL-4-secreting cells, in response to sporozoite antigen, were detected in the spleen and mesenteric lymph nodes of the beta-glucan-treated groups only. In conclusion, the i.g. and s.c. oat beta-glucan treatment increased the resistance to E. vermiformis infection in immunosuppressed mice.

Serum haptoglobin as an indicator of the acute phase response in bovine respiratory disease.

The early stages of the host response to infectious agents include a number of physiologic changes, collectively known as the acute phase response. The acute phase response is comprised of reactions localized at the site of infection, as well as the initiation of systemic responses, which include a rapid increase in the serum concentration of some proteins, known as acute phase proteins (APP). Using polyacrylamide gel electrophoresis, we detected two APP of approximately 22 and 37 kDa molecular weight in sera obtained from cattle with bovine respiratory disease (BRD). Based on their presence in the sera of sick, but not normal animals, the molecular weights, N-terminal amino acid sequence analysis, and the ability to bind hemoglobin, we identified these proteins as the alpha and beta subunits of haptoglobin. The haptoglobin molecule and the alpha subunit were isolated from serum, purified, and used to produce monoclonal and polyclonal antibodies. With these reagents, an enzyme linked immunosorbent assay was developed to measure the concentration of haptoglobin in bovine serum. Using an experimental model of BRD induced by a sequential challenge of calves with bovine herpesvirus type-1 and Pasteurella haemolytica, we observed a temporal relationship between the increase in haptoglobin concentration in serum and the onset of bacterial infection. The haptoglobin concentration ranged from undetectable in the serum of most calves prior to challenge, to greater than 1 mg ml(-1) in over one-third of the calves at the height of disease. Furthermore, the concentration of haptoglobin was associated significantly with other measures of the severity of disease. Together, these results indicate that quantification of acute phase proteins in animals with BRD could be a valuable diagnostic and prognostic aid.

Passive immunization against somatostatin increases resistance to Eimeria vermiformis infection in susceptible mice.

The effect of in vivo immunoneutralization of somatostatin (SRIF) on Eimeria vermiformis intestinal infection was studied in resistant (BALB/c), and susceptible (C57BL/6) mouse strains. An anti-SRIF monoclonal antibody (MAb-SRIF) was used to passively immunize the mice by intraperitoneal injection. The animals were subsequently orally infected with oocysts of E. vermiformis. Individual fecal samples were collected daily for 21 days to monitor the kinetics of oocyst shedding. The fecal oocyst shedding was significantly higher in the C57BL/6 strain than in the BALB/c strain (P < 0.01). Passive immunization with MAb-SRIF in the C57BL/6 mice significantly reduced the number of oocysts in feces (P < 0.05), when compared to the infected non-immunized mice of the same strain. Infected BALB/c mice showed no difference in oocyst shedding in response to the passive immunoneutralization with MAb-SRIF. In conclusion, passive immunization with MAb-SRIF increased resistance to E. vermiformis-infection in the susceptible C57BL/6 mice, but not in the resistant BALB/c mice. This suggests that SRIF modulates gut immune function in parasitic infection.

Induction of systemic and mucosal immune responses following immunization with somatostatin-avidin complexes incorporated into ISCOMS.

Synthetic, biotinylated somatostatin-14 (Somatotropin Release-Inhibiting Factor; SRIF) was conjugated to avidin, and the resulting complex incorporated into immune-stimulating complexes (ISCOMS). The ISCOMS were used to study the systemic and mucosal immune responses induced by parenteral and gastrointestinal vaccination. Mice were immunized by intraperitoneal (IP) and intragastric (IG) routes and subsequently by either IP or IG secondary immunizations (groups-IP/IP; IP/IG; IG/IG). Antigen specific IgG and IgA antibody secreting cells (ASC) from the spleen, mesenteric lymph nodes (MLN) and Peyer's patches (PP's) were studied by an enzyme-linked immunospot assay (ELISPOT). Specific proliferative responses of spleen cells to avidin and to SRIF were measured. Immunization IP/IP evoked the highest serum IgG levels to avidin and to SRIF as well as the highest numbers of splenic IgG isotype ASC. The greatest IgA response in MLN and PP's was induced by IP/IG immunization. Only marginal mucosal immunity and no splenic cell specific proliferative responses were found by IG/IG immunization. These results indicate that ISCOMS are an effective delivery system for protein-peptide antigens. The ISCOMS system described elicited systemic and mucosal antibody immune responses, and primed specific proliferative response when administered IP/IG. This offers another approach for the design and delivery of mucosally administered peptide vaccines.

Assembly of recombinant rotavirus proteins into virus-like particles and assessment of vaccine potential.

Rotavirus structural proteins VP4, VP6 and VP7 from Bovine Rotavirus Strain C486 were cloned and expressed in a baculovirus expression system. Combinations of the proteins were assembled into a series of virus-like particles, and a murine model was used to determine the capacity of the recombinant proteins and particles to induce protective immunity. All of the proteins induced humoral immunity as measured by an ELISA against whole virus. However, only the antisera from animals immunized with VP4 neutralized virus and inhibited haemagglutination. Challenge of neonates born to animals immunized with VP4 protein on assembled particles or in cell lysates showed protection against challenge with both homologous (bovine C486) and heterologous (SA-11) strains of rotavirus. In contrast, the offspring of mice immunized with VP6 were only partially protected. Neonates of animals immunized with virus-like particles composed of VP7 assembled on VP6 spherical particles were protected against challenge with the homotypic virus and significantly protected from a heterotypic challenge whereas unassembled VP7 protein provided only partial protection against challenge.

Central neurocytoma.

One case of central neurocytoma is presented. A review of the literature suggests that the condition is more common than previously recognised. The pathological features are discussed and the role of surgery and radiotherapy in the management of the condition is discussed.

Cytokine activity in bovine mammary gland secretions during the periparturient period.

The presence of cytokine activity in periparturient bovine mammary secretions was evaluated. Mammary secretions were modified for use in biological assays for interleukin-2 (IL-2) like and antiviral activity. The level of IL-2 like activity in mammary gland secretions was lower during the last week of gestation when compared to levels detected approximately two weeks prepartum. Antiviral titers gradually increased as parturition approached. Results from Western blots indicated that the antiviral activity observed in prepartum secretions may be due to tumor necrosis factor (TNF). Interferons (IFN) were not detected in the colostrum samples.

Heterotypic passive protection induced by synthetic peptides corresponding to VP7 and VP4 of bovine rotavirus.

We have evaluated the potential of two peptides derived from highly conserved regions of rotavirus outer capsid proteins (VP7 and VP4) to act as a rotavirus vaccine. The capacity of peptides coupled to rotavirus VP6 spherical particles to provide passive protection in a murine model was compared with the protection induced by peptide-keyhole limpet hemocyanin (KLH) conjugates. Female mice were immunized a total of three times before and during pregnancy. Suckling mouse pups were challenged at 7 days of age with either homologous or heterologous rotavirus serotypes. The efficacy of vaccination was determined by analyzing the clinical symptoms and measuring xylose adsorption in the intestine. In this model the VP4 peptide-VP6 conjugate provided protection equal to that obtained using bovine rotavirus (BRV) as the immunogen. The VP7 peptide-VP6 conjugate provided slightly less protection than the VP4 peptide-VP6 conjugate. A mixture of the VP4 peptide-VP6 and VP7 peptide-VP6 conjugates provided better heterologous protection than immunization with BRV. In contrast, KLH-conjugated peptides provided only partial protection. The significance of a synthetic-peptide-based rotavirus vaccine in the prevention of rotavirus infections is discussed.

"Heartstart Scotland"--initial experience of a national scheme for out of hospital defibrillation.

OBJECTIVE: To determine the outcome of out of hospital defibrillation in Scotland during the year after the introduction of automated external defibrillators in October 1988. DESIGN: Retrospective analysis of ambulance service reports and hospital records. SETTING: Scottish Ambulance Service and acute receiving hospitals throughout Scotland. MAIN OUTCOME MEASURES: Delay from cardiac arrest to first defibrillator shock; vital state on arrival at hospital accident and emergency department; survival to hospital discharge. RESULTS: During the study period 268 defibrillators were purchased by public subscription and 96% of the 2000 ambulance crew underwent an eight hour training programme in cardiopulmonary resuscitation and defibrillation. A total of 1111 cardiac arrests were recorded, and defibrillation was indicated and undertaken in 602 (54%) patients, mean age 63 (range 14-92) years. A spontaneous pulse was present on arrival at hospital in 180 (30%) of the defibrillated patients, and 75 (12.5%) were subsequently discharged alive. As expected, the likelihood of survival was inversely related to the delay from the onset of cardiac arrest to the time of the first shock and was greater in the case of witnessed arrest. If ventricular fibrillation occurred after the arrival of the ambulance, survival to discharge was 33%. CONCLUSIONS: An effective scheme for out of hospital defibrillation can be introduced rapidly, and with limited training implications and costs, by the use of automated external defibrillators in ambulances.

Rotavirus particles function as immunological carriers for the delivery of peptides from infectious agents and endogenous proteins.

A major problem in the development of useful animal subunit vaccines has been the generation of immune responses to weakly immunogenic molecules. For this purpose a new and effective delivery system has been devised. This system is based upon the inner capsid of bovine rotavirus. Under the appropriate conditions, the inner capsid protein, designated BP6, can be made to self-assemble in vitro and form spherical particles. These particles possess an inherent capacity to target to cells of the immune system. Exploitation of these properties has led to the development of technology to couple antigens to the VP6 particles such that the sphere acts as a novel immunological carrier. This is based on a "binding peptide" derived from another rotavirus peptide, VP4, as well as on more traditional techniques of chemical coupling. We have coupled peptides or proteins to this carrier via the binding peptide and have shown that every epitope tested to date gave excellent immune responses. Furthermore, using this carrier, immunity has been developed without the use of adjuvants. This has far-reaching implications for animal and human immunization.

Mapping of 10 epitopes on bovine herpesvirus type 1 glycoproteins gI and gIII.

In order to map some of the immunologically important sites on bovine herpesvirus type 1 (BHV-1), deleted, truncated, and hybrid forms of glycoproteins gI and gIII were expressed in transfected murine LMTK- cells. The cells were tested for reactivity with a panel of 16 gI- or gIII-specific monoclonal antibodies (MAbs) possessing conformation-independent antigen binding properties. This panel represented five epitopes on gI and five epitopes on gIII. For gI, two epitopes were mapped between residues 68 and 119, one epitope was mapped between residues 370 and 440, one epitope was mapped to the vicinity of residue 487, and one epitope was mapped between residues 744 and 763. For gIII, three epitopes were mapped between residues 22 and 150, one epitope was mapped between residues 140 and 240, and one epitope was mapped between residues 230 and 287. The location of the gI epitope in the vicinity of residue 487, which was recognized by a virus-neutralizing MAb, was verified by synthetic peptide binding studies. The epitope locations were consistent with proposed models for the structure of gI and gIII, and comparable to some of the epitope locations reported for the homologous glycoproteins of herpes simplex virus type 1. The implications of these results for development of a subunit vaccine against BHV-1 are discussed.

Non-traumatic cerebrospinal-fluid rhinorrhoea in cases of primary empty-sella syndrome.

Non-traumatic cerebrospinal-fluid rhinorrhoea is a rare condition. Its insidious onset may occur with a sneezing or coughing episode which may lead to an incorrect diagnosis of allergic rhinitis or vasomotor rhinorrhoea. Two cases that occurred in association with primary empty-sella syndrome are described--in the second case, the fistula arose from the pituitary fossa. The history, incidence, clinical profile, investigation and management of this condition are reviewed.

The use of computed-tomographic-directed stereotaxis in the diagnosis of intracerebral lesions.

The technique of computed-tomographic-directed stereotaxic biopsy of cerebral lesions is described, and our series of 24 procedures on 23 patients without mortality or morbidity is presented. This technique provides neurosurgeons with an improved method of performing cerebral biopsies.