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Clozapine is an atypical antipsychotic agent with a novel pharmacological profile and multiple clinical properties. Because of its side effects, it is recommended in treatment of severe resistant schizophrenia for which purpose it is remarkably effective. Little is known about the safety profile of clozapine during pregnancy and labour and because it is now used more commonly to manage schizophrenia, it is important that we as anaesthetists are aware of its many interactions and potential side effects. We present a case of a successful emergency caesarean section in a schizophrenic patient on clozapine treatment.

Recent work has shown that thin film quasicrystal coatings have unique properties such as very high electrical and thermal resistivities and very low surface energy. Aluminum-based quasicrystals are insulator alloys composed of approximately 70% of aluminum. The corrosion related properties of aluminum-based quasicrystal thin film coatings have been studied on quasicrystal-coated AA-2024 substrates. The thin film deposition parameters are discussed. Results of microstructural and surface chemistry analyses of the quasicrystal films are presented. The corrosion protection properties of the films have been studied by potentiodynamic scan and electrochemical impedance spectroscopy. Analysis of the electrochemical data indicates that nanostructured quasicrystal films significantly resist corrosion of AA2024-T3 substrates in constant immersion environment. Morphology studies and electrochemical analysis of quasicrystal films have shown that quaternary Al-based quasicrystal thin films possess unique corrosion control properties. Superior resistance to electrolyte attack makes these coatings strong candidates for corrosion-resistant surface treatment of Al alloys. These films can be utilized as conversion coatings for Al substrates or incorporated into a full coating system containing an organic primer and a topcoat.

Quasicrystals belong to a particular type of solids, which consist of highly symmetric atom clusters. The structure is neither periodically ordered, as in crystalline materials, nor amorphous, as in a glass. Recent work has shown that thin film quasicrystal coatings can have unique properties such as very high electrical and thermal resistivities and very low surface energy, which may result in interesting corrosion properties. For example, aluminum alloy based quasicrystals are insulator alloys containing about 70% of aluminum. Other interesting properties involving, for instance, adhesion, corrosion, friction, and hardness suggest that quasicrystal coatings are promising materials for a variety of industrial applications. The corrosion related properties of aluminum alloy based quasicrystal thin film coatings have been studied on coated AA2024 substrates. The thin film deposition parameters are briefly discussed. Results of the microstructural, surface chemistry, and surface energy analysis of the quasicrystal films are presented. The corrosion protection properties of the films have been studied by potentiodynamic scan and electrochemical impedance spectroscopy. Analysis of the electrochemical data indicates that nanostructured quasicrystal films significantly resist corrosion of AA2024-T3 substrates in a constant immersion environment.

Mucosal addressin cell-adhesion molecule (MAdCAM-1) is a membrane-bound leukocyte receptor regulating both the passage and retention of leukocytes in mucosal tissues. A crystal structure for the two extracellular amino-terminal domains of human MAdCAM-1 has previously been reported, confirming their expected immunoglobulin superfamily topology. In this study, a second crystal structure of this fragment is described. Although the overall structure is similar to that previously reported, one edge strand in the amino-terminal domain is instead located on the opposite sheet. This alters the arrangement and conformation of amino acids in this region that have previously been shown to be crucial for ligand binding. MAdCAM-1 is also seen to form dimers within the crystal lattice, raising the possibility that oligomerization may influence the biological role of this adhesion molecule.

Low resistance ohmic contacts are difficult to form on p-type GaN and AlGaN due to the relatively high ionization energy of Mg in GaN and AlGaN. A carbon-doped GaAs grown on p-GaN prior to ohmic metallization has been shown to improve contact resistance to p-GaN. npn AlGaN/GaN heterojunction bipolar transistors and GaN bipolar junction transistors have been demonstrated by employing a regrowth C-doped GaAs to the p-GaN base regions. GaN/AlGaN epilayers were grown with a molecular beam epitaxy system and C-doped GaAs (1020 cm−3) was regrown on the devices (∼500 A) by metal organic chemical vapor deposition using SiO2 as mask. Very high current densities were achieved for common base operation in both device types and devices were operable at 250°C.

The dc characteristics of pnp GaN/AlGaN heterojunction bipolar transistors are simulated using a quasi-3D-model. The effects of base doping and thickness, contact geometry and device operating temperature on dc current gain have been examined. Maximum gains of ∼50 are expected for high quality materials and an optimized layer design. For similar layer thicknesses, npn devices have higher gains than the pnp structures, but the latter does not suffer from a high base sheet resistance.

GaN Bipolar Junction Transistors and GaN/AlGaN Heterojunction Bipolar Transistors were characterized at temperatures up to 250–300°C and power densities >10 kW cm −2 . The breakdown voltage in both types of devices decreased at higher temperatures, with less degradation in the BJTs. At low current levels, the offset voltages were 2–3 V but increased at higher currents.

Critical nitride-based p-n junction issues relating to wide bandgap bipolar device performance include minority carrier lifetime, defect related current characteristics and ohmic contact properties. Recent developments in p-GaN deposition processes resulted in GaN p-i-n UV photodetectors with improved deep UV responsivity, visible light rejection and shunt resistance characteristics. From the device data, the electron diffusion length in p-GaN doped at 1·1018 cm−3 was estimated to be 790 A, and the minority carrier lifetime in the p-GaN was estimated to be 24 ps to 0.24 ns. Improved junction electrical characteristics were achieved using MBE deposition on GaN buffers grown by MOCVD. NiAu ohmic contacts were also made to p-GaN with specific contact resistances less than 10−4 Ω·cm2.

The crystal structures of two pairs of Fab fragments have been determined. The pairs comprise both a murine and an engineered human form, each derived from the antitumor antibodies A5B7 and CTM01. Although antigen specificity is maintained within the pairs, antigen affinity varies. A comparison of the hypervariable loops for each pair of antibodies shows their structure has been well maintained in grafting, supporting the canonical loop model. Detailed structural analysis of the binding sites and domain arrangements for these antibodies suggests the differences in antigen affinity observed are likely to be due to inherent flexibility of the hypervariable loops and movements at the VL:VH domain interface. The four structures provide the first opportunity to study in detail the effects of protein engineering on specific antibodies. Proteins 29:161–171, 1997. © 1997 Wiley-Liss, Inc.

The n -3 and n -6 fatty acids are transferred across the placenta with consistently higher 22:6 n -3 and lower 18:2 n -6 in fetal than maternal plasma. This study sought to determine whether maternal and fetal cord blood red blood cell (RBC) phospholipid fatty acids show similar saturation with 22:6 n -3, and also addressed the relationship between 18:2 n -6 and Δ6 desaturase product/precursor ratios for 97 mothers and newborns. Despite higher fetal than maternal plasma phospholipid 22:6 n -3, the maternal and fetal RBC phospholipid 22:6 n -3 showed similar curvilinear relationships to the plasma phospholipid 22:6 n -3. Risk of failure to achieve high RBC phospholipid 22:6 n -3 increased sharply below a plasma phospholipid 22:6 n -3 of 6.5g/100g fatty acids. Higher maternal and fetal 18:2 n -6 was associated with lower RBC phospholipid 22:6 n -3/22:5 n -3, 22:5 n -6/22:4 n -6 and 18:3 n -6/18:2 n -6. These findings suggest low placental transfer of 18:2 n -6 may be a specific mechanism to prevent inhibition of fetal Δ6 desaturase and facilitate fetal cellular phospholipid 22:6 n -3 accretion.

A congenital rhabdomyosarcoma presented as a partially necrotic mass on the left forearm on delivery at term. Ulceration and persistent bleeding were managed by primary curettage followed by local resection including partial excision of the muscles of the extensor compartment of the forearm. The defect was resurfaced with a split skin graft. The surgery was followed by chemotherapy according to the IVA regime. There was no recurrence at 2 years of age and the limb was fully functional. The presentation and management of rhabdomyosarcoma are discussed.

Low resistance ohmic contacts are difficult to form to p-type GaN and AlGaN due to the unavailability of growth methods for highly p-doped GaN and AlGaN. A p-type carbon-doped GaAs regrowth on p-GaN prior to ohmic metallization has been shown in previous work to improve contact resistance to p-GaN [13]. Applying the regrowth method to the p-base regions of npn structured bipolar transistors, AlGaN/GaN heterojunction bipolar transistors and GaN bipolar junction transistors have been demonstrated. GaN/AlGaN epilayers were grown with a molecular beam epitaxy system. Highly carbon-doped p-GaAs (1020 cm−3) was regrown on the devices (∼500 Å) in the base contact region by metal organic chemical vapor deposition after emitter mesa etching. Emitter and base mesa structures were formed by Inductively Coupled Plasma etching under low damage conditions with a Cl2/Ar chemistry. SiO2 was used for emitter sidewall formation to reduce leakage current to the emitter, as well as for a mask for GaAs base regrowth. Very high current densities were obtained for common base operation in both device types. The devices were operable at 250 °C.

The three-dimensional structure of the Fab fragment of the murine monoclonal antibody A5B7, which is specific for carcinoembryonic antigen (CEA) a protein expressed on carcinoma cell surfaces, has been determined. The structure was solved by molecular replacement and has been refined to an R factor for 21.2% (all data 8-2.1 A). The conformation of the hypervariable loops, which form the antigen binding site, are consistent with canonical loop predictions. Hypervariable loop H3 is unusual in surface exposing many hydrophobic groups at the expense of burying an aspartic acid in the protein core. Other regions of the structure that influence the conformation of the binding site are identified. This structure forms a basis for analysing the effects of amino-acid substitutions in both hypervariable and framework regions in engineering studies of the A5B7 antibody.

The crystal structure of a chimeric Fab' fragment of a monoclonal antibody is presented. The Fab' comprises the murine light chain and heavy chain variable domains of the carcinoma-binding antibody B72.3 fused to the constant domain of human kappa, and the first constant domain and hinge domain of human gamma 4, respectively. A model for the Fab' has been determined by molecular replacement and refined to a resolution of 3.1 A with an R-factor of 17.6%. The additional residues that distinguish a Fab' from a Fab fragment are seen to be disordered in the crystals. The H3 hypervariable loop is short and adopts a sharp hairpin turn in a conformation that results from an interaction between the lysine side-chain of H93 and the main-chain carbonyl group of H96. The remaining hypervariable loops display conformations similar to those predicted from the canonical structures approach, although loop H2 is apparently displaced by a salt-bridge formed between H55 Asp and the neighbouring H73 Lys. These and other features of the structure likely to be important in grafting the hypervariable loops to an otherwise human framework are discussed.

Crystals have been obtained of a chimaeric Fabt′ fragment that binds to a tumour-associated mucin-like glycoprotein TAG72. The Fab′ fragment comprises the variable heavy and light-chain domains of a murine monoclonal antibody, B72.3, coupled to human γ4 and κ constant regions. The crystals are orthorhombic and belong to the space group P212121, with unit cell dimensions a = 67.9 A , b = 94.2 A and c = 208.8 A . Diffraction to 2.6 A resolution was observed using synchrotron radiation. Despite the acute radiation sensitivity of the crystals a full native data set has been collected using the Weissenberg camera at the Photon Factory synchrotron. These data will be used for molecular replacement calculations in an attempt to elucidate the structure of this chimaeric Fab′ fragment.

An extension to the traditional two-element array crosseye interferometric electronic jamming technique is investigated. Simulations are performed to obtain excitations for multiple-emitter linear arrays that produce distorted wavefronts over desired regions of space. This results in a greater number of degrees-of-freedom and a better ability to control the desired field pattern. The crosseye effect can be achieved over wider sectors, but only by increasing array power. The technique is extended to two-dimensional arrays and is applicable to multi-function radar antennas. Experimental measurements performed on a four-emitter array demonstrate the feasibility of the technique. Good agreement with predictions is shown.

This paper introduces an algebra for expressing security policies with particular application to cryptographic methods of storing information. The algebra is composed of operands which are cryptographic functions, dependent upon an algorithm and a key, and a set of operators. By combining expressions in meaningful ways, security policies can be represented. The advantages of this are that the categories and classifications of information can clearly be seen, the representation of security policies can be concise, and a model represented in the algebra may be translated readily into a configuration of cryptographic keys, thus simplifying the otherwise difficult task of verifying security.

The findings on gallium-67 scans were compared with the findings of standard techniques (X-ray chest, lymphangiography, clinical examination, and laparotomy findings) in patients with lymphoma, mainly at presentation, but sometimes on follow-up. The objective was to ascertain the reliability of this non-invasive technique in detecting lymphomatous deposits, and to assess its place in the battery of investigations which may be used in clinical staging of lymphomas. One hundred and sixty-six patients were studied, in whom 198 gallium-67 scans were performed. The results indicated that detection of mediastinal and upper para-aortic node involvement was the most significant function, and such detection might alter clinical staging, and, therefore, therapy. Gallium-67 was unhelpful in splenic scanning, being positive usually only in cases which had clinically detectable involvement. Unsuspected lung and bone lesions were found occasionally, and this was of considerable importance. Gallium-67 scanning is regarded as an important, non-traumatic additional investigation, clinically useful in staging lymphomas.

1. 1. Intracellular recordings were made from Helix, Hirudo and Limulus central neurons and from Eupagurus leg muscle and extracellular recordings from rat lateral geniculate neurons. The actions of 2,3-, ,2,4-, 2,5- and 2,6-piperidine dicarboxylates were tested on those preparations for both direct effects and interactions with the response to L -glutamate. 2. 2. All four piperidine analogues were devoid of either reproducible direct or indirect effects on Helix and Limulus neurons save that the 2,5-analogue did mimic the action of L -glutamate on Limulus neurons which were inhibited by glutamate. 3. 3. On Hirudo and rat neurons and on Eupagurus muscle, all four piperidines mimicked the action of L -glutamate, all were weak agonists on rat neurones while on Hirudo neurons the 2,5-analogue was the most potent but on Eupagurus muscle, the 2,3- and 2,6-analogues were the most potent. 4. 4. All four piperidines potentiated the action of L -glutamate on rat and Hirudo neurons and on Eupagurus leg muscle and of muscle ejps. 5. 5. The piperidine analogues indicate that there are differences between the glutamate receptors used in the present study and provide some supportive evidence that the preferred conformation for glutamate on crab leg muscle is partially folded while for Hirudo neurons it is more extended.

Investigation of a 15-year-old white male patient with chronic granulomatous cheilitis revealed asymptomatic Crohn's disease of the lower gastrointestinal tract. This is reported to support the suggestion that chronic granulomatous cheilitis and Crohn's disease may be intimately related. Tests for nutritional status are shown to be important in the investigation and management of patients with this condition, being the first indication of any gastrointestinal pathology.

The activities of kainic acid and its derivatives alpha-ketokainic acid and dihydrokainic acid have been compared with L-glutamic acid as excitants of identified central neurons. The results are consistent with the view that the high activity of kainate is associated with unsaturation in the isopropylene side-chain. It is suggested that a reduction in the lipophilic nature of the alkene bond may cause a concomitant reduction in excitatory potency. This is discussed in relation to the mechanism of receptor activation by kainic acid.

The cause of the renal failure that occurs in approximately 20 percent of patients following allogeneic bone marrow transplantation is poorly understood. A patient is described in whom acute renal failure occurred one week after allogeneic bone marrow transplantation. The onset of the renal failure was associated with the demonstration of anti-Lewis antibodies in the patient's serum, which could only have been derived from donor lymphocytes. Recovery of renal function coincided with the disappearance of the Lewis antibody. It is postulated that Lewis incompatibility between graft and host tissue may have contributed to the renal failure in this patient and that incompatibility associated with determinants present on renal cells may account for other instances of acute renal failure following allogeneic bone marrow transplantation.

In 40 patients assessed for splenic enlargement prior to splenectomy, clinical examination and ultrasonic scanning gave equally accurate results when compared with splenic weight after removal. In the 22 patients having staging laparotomy and splenectomy for Hodgkin's disease, ultrasound was unable to assess accurately the presence of tumour deposits.

From the Departments of Pathology and Medicine, McMaster University, the Canadian Red Cross Blood Transfusion Service, and the McMaster Division of the Chedoke-McMaster Hospitals, Hamilton, Ontario, Canada. Requests for reprints should be addressed to Dr. M. A. Blajchman, Room 2N31, Department of Pathology, McMaster University Medical Centre, 1200 Main Street West, Hamilton, Ontario L8N 325, Canada. Manuscript accepted July 6, 1984. The cause of the renal failure that occurs in approximately 20 percent of patients following allogeneic bone marrow transplantation is poorly understood. A patient is described in whom acute renal failure occurred one week after allogeneic bone marrow transplantation. The onset of the renal failure was associated with the demonstration of anti-Lewis antibodies in the patient’s serum, which could only have been derived from donor lymphocytes. Recovery of renal function coincided with the disappearance of the Lewis antibody. It is postulated that Lewis incompatibility between graft and host tissue may have contributed to the renal failure in this patient and that incompatibility associated with determinants present on renal cells may account for other instances of acute renal failure following allogeneic bone marrow transplantation.