Workplace exposure to rosin-based solder flux fume during hand soldering

The patterns and extent of exposure to rosin based solder flux fume have been investigated in two surveys and a number of individual site visits carried out by the UK Health and Safety Executive (HSE). Determination of solder fume was by measurement of airborne resin acid particulate. Both static and personal sampling was carried out over time periods ranging from 15 minutes to several hours. Resin acid concentrations were found to vary from less than 1 microgram m-3 to 2289 micrograms m-3. The effects of various types of local exhaust ventilation on resin acid concentrations have been observed. On-tool tip extraction systems were generally found to be the best control measure available; however good design, positioning and system maintenance is essential for efficient capture of the fume. The resin acid concentrations detected at these twenty-six sites suggest that the proposed British long and short term occupational exposure limits are realistically attainable targets, particularly where good working practices and/or effective fume control measures are in place.

Reducing risks to children in vehicles with passenger airbags

This review examines the risk that passenger airbags pose for children and discusses behavioral and technologic measures aimed at protecting children from airbag deployment. Although airbags reduce fatal crash injuries among adult drivers and passengers, this safety technology increases mortality risk among children younger than age 12. The magnitude of the risk is multiplied when children are unrestrained or restrained improperly. As new vehicles are resold to buyers who tend to be less safety-conscious than new car owners, the number of children endangered by passenger airbag deployment may increase. For vehicles already in the fleet, strong measures are required to secure children in the rear seat and increase the proper use of appropriate restraint systems through police enforcement of laws. One promising strategy is to amend child passenger safety laws to require that parents secure children in the rear seats. For future vehicles, a mandatory performance standard should be adopted that suppresses airbag deployment automatically if a child is located in the front passenger seat. Other promising improvements in airbag design also are discussed. Major changes in passenger airbag design must be evaluated in a broad analytical framework that considers the welfare of adults as well as children.

The Fischer rat thyroid cell line FRTL-5 exhibits a nondiploid karyotype

The FRTL-5 cell line is a stable thyroid cell line derived from the thyroid gland of the Fischer rat under defined culture conditions, which has been widely adopted as a model system for the study of thyroid cell function and for bioassay. While characterizing by flow cytometry FRTL-5 cells that were supplied to this laboratory by ATCC (American Type Cell Collection), we discovered that the cells (ATCC CRL8305) were not diploid, having approximately twofold the DNA content relative to a diploid control. The increase in DNA content also applied to cells originally supplied by the ATCC (described as passage 14) that when counted in metaphase had a modal chromosomal count of 84, indicating tetraploid status, double the expected 42 of a diploid rat cell. In a private communication, the ATCC confirmed these findings which nevertheless are contrary to previous literature reports where they were reported to be diploid. Tetraploid cells are less sensitive to thyrotropin (TSH) as measured by cyclic adenosine monophosphate (cAMP) production, compared with diploid cells (p = < 0.001). Despite similar 3H-thymidine uptake in 0.2% fetal calf serum, tetraploid cells show increased 3H-thymidine uptake in 5% fetal calf serum in the absence of TSH (p = 0.001). The origin of these chromosomal changes is unclear, but these findings must raise doubts regarding the suitability of the tetraploid FRTL-5 cell line as a model for studies of human or animal thyroid physiology.

Variability of house-dust-mite allergen levels within carpets

Sensitization and exposure to house-dust-mite allergens is an important cause of asthma. Standardized, reliable, and reproducible methods for measuring exposure are essential for the assessment of the relationship between exposure, sensitization, and asthma. This study investigated the variability of the house-dust-mite allergen Der p 1 concentration in reservoir dust collected within whole carpets in living rooms and bedrooms. The carpets of nine bedrooms and 11 living rooms were sampled. Each room was divided into 1 m2 areas measured from wall to wall where the carpet was accessible. Reservoir dust samples were collected by vacuuming each 1 m2 area for 2 min. Der p 1 was assayed by a two-site monoclonal-antibody-based immunometric ELISA. Der p 1 was detectable in the carpets of all nine bedrooms and six of the 11 living rooms. Within these 15 rooms, there was a wide range of Der p 1 levels. The smallest range of allergen within a single room was 0.9 microgram Der p 1/g dust (0.2 and 1.1 micrograms/g; 5.5-fold difference), and the largest was 149.2 micrograms Der p 1/g dust (0.8 and 150 micrograms/g; 192-fold difference). The mean range of allergen levels in the living rooms was 11.5 micrograms Der p 1/g of dust, and the mean coefficient of variation of these rooms was 80.2%, illustrating the huge variation of mite allergen levels within each room. The variation within bedrooms was also large, with a mean coefficient of variation value of 88.7%. The coefficient of variation was significantly lower around soft furnishings or beds (57%) than in the rest of the room (89.3%), with the mean difference being 32% (95% CI 2-63%; P = 0.04). In conclusion, this study has shown that there is a great variation of Der p 1 levels between areas within a room. No consistent pattern of distribution of mite allergen within a room was found. Der p 1 levels in areas around soft furnishings and beds varied less than the levels in the rest of the room.

A comparative analysis of six audit systems for mental health nursing

PURPOSE

To devise an analytical framework to help identify strengths and weaknesses in the audit process as specified by existing psychiatric nursing audit systems, in order to analyse current audit practice and identify improvements for incorporation in the Newcastle Clinical Audit Toolkit for Mental Health.

DATA SOURCES

Published material relating to the following six systems: the Central Nottinghamshire Psychiatric Nursing Audit; Psychiatric Nursing Monitor; Standards of Care and Practice; Achievable Standards of Care; Quartz; and Quest.

DATA EXTRACTION

Comparison of the six systems according to an analytical framework derived from detailed empirical study (structures, processes and outcomes) of one of them in use and the educational evaluation literature. Examination of the extent to which guidance is provided for operating the systems and for wider process-related aspects of audit.

RESULTS OF DATA SYNTHESIS

Five of the systems failed to specify some important elements of the audit process. Conceptually, the six systems can be divided into two main types: 'instrument-like' systems designed along psychometric lines and which emphasize the distance between the subjects of audit and the operators of the systems, and 'tool-like' systems which exploit opportunities for care setting staff to engage in the audit process. A third type of system is the locally-developed system which is offered to a wider audience but which does not make the same level of claim to universal applicability.

CONCLUSION

The analytical framework allows different approaches to audit to be compared and contrasted not only according to the techniques used, but also according to process issues. The analysis of six systems revealed a variety of different techniques and procedures which can facilitate, in a methodologically rigorous manner, practitioner and other stakeholder involvement in audit processes.

Distribution, aerodynamic characteristics, and removal of the major cat allergen Fel d 1 in British homes

BACKGROUND

Sensitisation to cat allergen (Fel d 1) is an important risk factor for asthma in the UK. A study was undertaken to investigate the distribution of cat allergen in British homes, the aerodynamic characteristics and particle size distribution of airborne Fel d 1, and the method of removing it.

METHODS

Dust was collected from 50 homes with a cat and from 50 homes without a cat, and airborne levels of Fel d 1 were measured in 50 homes with a cat and 75 homes without a cat. Particle size distribution was determined using an Andersen sampler (8 hours/day) in 10 homes with cats. This was repeated on five separate days in a house with four cats, and then one, two, four, seven, and 14 days after the cats were removed from the living room area. The effect of high efficiency particulate air (HEPA) cleaner on airborne levels of Fel d 1 was investigated in seven homes with cats. Samples were collected on two separate days from two rooms of each house concurrently, one of which contained the cat, one day with the HEPA cleaner on and the other day as a control. Three one hourly samples were collected over a nine hour period (baseline, 4-5 hours, 8-9 hours) using a high volume dust sampler (air flow rate 60 l/min) and the air sample was collected onto a microglass fibre filter (pore size 0.3 micron).

RESULTS

Fel d 1 concentrations were much lower in houses without a cat than in those with a cat (260-fold difference (95% CI 167 to 590) in living room carpets: geometric mean (GM) 0.9 microgram/g (range 0.06-33.93) versus 237 micrograms/g (range 2.8-3000); 314-fold difference (95% CI 167 to 590) in upholstered furniture: 1.21 micrograms/g (range 0.06-61.9) versus 380 micrograms/g (range 7.1-6000); 228-fold difference (95% CI 109 to 478) in bedroom carpets: 0.24 microgram/g (range 0.06-2.24) versus 55 micrograms/g (range 0.06-2304); and 215-fold difference (95% CI 101 to 456) in mattresses: 0.2 microgram/g (range 0.06-2.3) versus 55 micrograms/g (range 0.06-3400). Airborne levels of Fel d 1 were detected in all houses with cats, and the levels varied greatly between the homes (range 0.7-38 ng/m3). Low concentrations of airborne Fel d 1 (range 0.24-1.78 ng/m3) were found in 22 of 75 homes without a cat. Although airborne Fel d 1 was mostly associated with large particles (> 9 microns, approximately 49% of the allergen recovered), small particles (< 4.7 microns) comprised approximately 23% of the total airborne allergen. Total airborne Fel d 1 was reduced by 61.7% two days after removal of the cat but this was due predominantly to the decrease in larger particles (> 4.8 microns) which fell to 13% of their baseline level. Fel d 1 levels associated with small particles (< 4.8 microns) remained largely unchanged on days 1, 2 and 4 and then slowly decreased to 33% of the baseline levels at day 14. With HEPA cleaner a significant reduction in airborne Fel d 1 was observed compared with the control sampling (GM 5.04-0.88 ng/m3 versus 3.79-1.56 ng/m3 at baseline and 8 hours, active versus control group; p = 0.008).

CONCLUSIONS

Airborne Fel d 1 was detectable in undisturbed conditions in all homes with cats and in almost a third of homes without cats. In houses with cats a significant proportion (23%) of airborne Fel d 1 was associated with small particles (< 4.7 microns diameter). Removal of the cat from the living room and bedroom areas of the home and the use of HEPA air cleaner reduced airborne levels of cat allergen in homes with cats, but the reduction following cat removal was not evenly spread across the particle size range.

Structural comparison of the enzymatically active and inactive forms of delta crystallin and the role of histidine 91

The major soluble protein component of avian and reptilian eye lenses, delta crystallin, is highly homologous to the urea cycle enzyme, argininosuccinate lyase (ASL). In duck lenses there are two highly homologous delta crystallins, termed delta I and delta II, that are 94% identical in amino acid sequence. While delta II crystallin has been shown to exhibit ASL activity in vitro, delta I crystallin is inactive. The X-ray structure of a His to Asn mutant of duck delta II crystallin (H91N) has been determined to 2.5 A resolution using the molecular replacement technique. The overall fold of the protein is similar to other members of the superfamily to which this protein belongs, with the active site located in a cleft between three different monomers of the tetrameric protein. A reexamination of the kinetic properties of the H91N mutant reveals that the mutant has 10% wild-type activity. The Vmax of the mutant protein is identical to that of the wild-type protein, but a 10-fold increase in the Michaelis constant is seen, suggesting that His 91 is involved in binding the substrate. In an effort to determine the reasons for the loss of enzymatic activity in delta I crystallin, a structural comparison of the H91N mutant with the enzymatically inactive turkey delta I crystallin has been performed. This study revealed a remarkable similarity in the overall structures of the two proteins. Three regions of secondary structure do differ significantly between the two models; these include the N-terminal tail, a loop containing residues 76-91, and a cis versus trans peptide linkage at residue Thr 322. The cis to trans peptide variation appears to be an interspecies difference between turkey and duck and is therefore not directly involved in the loss of enzymatic activity. All the residues implicated in the catalytic mechanism are conserved in both the active and inactive proteins, and given the linearity of the relationship between the enzymatic activity of duck delta I/delta II heterotetramers and their delta II content (Piatigorsky & Horwitz, 1996), it is evident from the structure that only one of the three domains that contributes to the active site is responsible for the loss of activity in the delta I protein. Given the structural differences found in domain 1 (N-terminal tail and 76-91 loop), we postulate that these differences are responsible for the loss of catalytic activity in the delta I crystallin protein and that the delta I protein is inactive because it no longer binds the substrate.

Human argininosuccinate lyase: a structural basis for intragenic complementation

Intragenic complementation has been observed at the argininosuccinate lyase (ASL) locus. Intragenic complementation is a phenomenon that occurs when a multimeric protein is formed from subunits produced by different mutant alleles of a gene. The resulting hybrid protein exhibits enzymatic activity that is greater than that found in the oligomeric proteins produced by each mutant allele alone. The mutations involved in the most successful complementation event observed in ASL deficiency were found to be an aspartate to glycine mutation at codon 87 of one allele (D87G) coupled with a glutamine to arginine mutation at codon 286 of the other (Q286R). To understand the structural basis of the Q286R:D87G intragenic complementation event at the ASL locus, we have determined the x-ray crystal structure of recombinant human ASL at 4. 0 A resolution. The structure has been refined to an R factor of 18. 8%. Two monomers related by a noncrystallographic 2-fold axis comprise the asymmetric unit, and a crystallographic 2-fold axis of space group P3121 completes the tetramer. Each of the four active sites is composed of residues from three monomers. Structural mapping of the Q286R and D87G mutations indicate that both are near the active site and each is contributed by a different monomer. Thus when mutant monomers combine randomly such that one active site contains both mutations, it is required by molecular symmetry that another active site exists with no mutations. These "native" active sites give rise to the observed partial recovery of enzymatic activity.

Identification of mutations contributing to the reduced virulence of a modified strain of respiratory syncytial virus

The nucleotide sequences of the genome of the RSS-2 wild type strain of respiratory syncytial (RS) virus, which is known to induce upper respiratory tract infection in adults, and that of the attenuated ts1C candidate vaccine derived from it by three cycles of mutagenesis and selection of temperature-sensitive (ts) mutants, have been determined. Comparison of the sequences has located the genetic changes which contribute to the reduced pathogenicity in adults of the candidate vaccine. Thirty-seven nucleotide changes distinguish the wild type and ts1C, 13 of which confer amino acid substitutions; no mutations are present in extragenic regions. Partial nucleotide sequencing of the genomes of the first stage ts mutant (ts1A) and the second stage ts mutant (ts1B), which were intermediates in the derivation of the third stage mutant ts1C, established that five mutations resulting in amino acid substitutions had been induced in the first cycle of mutagenesis, one in the second cycle, and seven in the third cycle. The unique mutation differentiating ts1B from ts1A substitutes an alanine for a threonine at residue 736 in the polymerase (L) protein. The occurrence of a mutation in ts1C inducing substitution of a phenylalanine for a serine residue at an adjacent site (731) suggests that mutations in this region of the polymerase can have significant attenuating effects. The data suggest also that a mutation in the F gene may contribute to the attenuated phenotype.

Accidental infant death and stroller-prams

A three-month-old boy and an eight-month-old boy died from accidental positional asphyxia and hanging, respectively, after being placed to sleep unsupervised in stroller-prams. Both infants had moved down towards the fronts of the stroller-prams. The younger infant fell out when the footplate collapsed and he was found hanging from a metal bar on the side. The older infant had partly slipped through the front and was suspended with his head and arms within the stroller-pram and with his face pushed firmly into the mattress by a horizontal metal bar. Stroller-prams are a potentially dangerous sleeping environment unless infants are closely supervised, gaps in the front of stroller-prams closed and upright footplates stabilised.

Social cognition in developmental language disorders and high-level autism

Two groups of children with contrasting types of developmental language disorder (phonologic-syntactic and semantic-pragmatic) were compared with a group of children with high-level autism and with a control group of normal children on tests of social cognition (theory of mind; social comprehension; and detection of eye direction). The similarly poor performances of the semantic-pragmatic group and the autistic group suggest that semantic-pragmatic language disorder lies on the autistic spectrum.

Hemispheric function in developmental language disorders and high-level autism

Two groups of children with contrasting types of developmental language disorder (phonologic-syntactic and semantic-pragmatic) were compared with a group of children with high-level autism and with a control group of normal children on a broad battery of neuropsychological tests, known to be sensitive to left-right hemisphere damage. Significant differences found between the groups suggest contrasting forms of hemispheric dysfunction.

Involving clients in clinical audits of mental health services

Involving clients in service audits is never straightforward. In developing a new audit system for use in mental health settings a review of the literature demonstrated that the concept of satisfaction, like quality, is problematic because it is multidimensional, it is affected by expectations, and may be defined differently by professionals and clients. Furthermore, it fails to address the notion of empowerment. However, the literature provided some clear methodological guidance about involving clients in clinical audit. Clients must be involved in defining audit topics, and the most appropriate techniques of data-collection are open-ended and qualitative. Clients can also be involved in the process of audit, particularly through conducting audits in collaboration with professionals. Evidence from the literature persuaded the authors to abandon the idea of developing an audit module on patient satisfaction, and instead to develop one with a clear focus on clients' perspectives, entitled "Clients' Appraisal of Care" as part of the Newcastle Audit System, with clients involved throughout.

A framework for identifying and managing risk in the operating theatre

There is much advice available about the development of risk management strategies within the NHS. There are booklets and magazines and there are many management consultancies willing to give advice on the development of strategies. NATN is also working on the development of advice on risk management within the operating theatre department and a document should be available at Congress this year. It was felt, however, that it may be useful to hear a little about the specific experience of the development of a strategy within one operating theatre area and Andrea Simpson, Directorate Nurse Manager for Clinical Services, West Lothian NHS Trust has recorded the development within the directorate. There has been some additional comment from the Director of Nursing and Quality within the Trust, Libby Campbell, who is responsible for risk management there.

The avian eye lens protein delta-crystallin shows a novel packing arrangement of tetramers in a supramolecular helix

BACKGROUND

Little is known of the intermolecular organization of crystallins in the protein-packed eye lens. The tetrameric structure of the 200,000 Da avian delta-crystallin, which is closely related to the enzyme argininosuccinate lyase and is characteristic of the accommodating, soft lens of birds, has recently been solved at atomic resolution at acidic pH. To help understand how delta-crystallin remains soluble at the very high concentrations found in the avian lens we have now crystallized turkey delta-crystallin at around neutral pH and examined its intermolecular interactions.

RESULTS

Turkey delta-crystallin has been crystallized around neutral pH. The X-ray structure has been solved at 4.5 A resolution in space group C2 with three and a half tetramers in the asymmetric unit. The symmetrical 222 tetramers have a novel packing arrangement consisting of continuous helices, with 7(3)2 non-crystallographic symmetry, in an approximately hexagonal close-packed array. The internal 222 symmetry of the tetramers allows different polymeric chains to be constructed, based on the tetramer-tetramer association observed in the crystalline helix. It is possible to build a model of a tubule of diameter 212 A that is very similar to observed tubules of bovine argininosuccinate lyase.

CONCLUSIONS

Elements of helical organization may occur in the concentrated solution of the avian eye lens where delta-crystallin is the prominent protein. The symmetry of the tetramer provides a choice in the direction of growth of a helix at each link so that highly hydrated irregular polymers may be formed rather than large compact regular structures that would not be compatible with a transparent lens.

Vaccination against schistosomiasis and fascioliasis with the new recombinant antigen Sm14: potential basis of a multi-valent anti-helminth vaccine?

Molecular cloning of components of protective antigenic preparations have suggested that related parasite fatty acid binding proteins could form the basis of the well documented protective, immune cross reactivity between the parasitic trematode worms Fasciola hepatica and Schistosoma mansoni. We have now confirmed the cross protective potential of parasite fatty acid binding proteins and suggest that it may be possible to produce a single vaccine that would be effective against at least two parasites, F. hepatica and S. mansoni of veterinary and human importance respectively.

High-performance liquid chromatographic assay of plasma thalidomide: stabilization of specimens and determination of a tentative therapeutic range for chronic graft-versus-host disease

Thalidomide is now widely used to treat chronic graft-versus-host disease, but its use is associated with non-teratogenic side effects such as peripheral neuropathy. To examine the value of monitoring plasma concentrations of the drug in such patients, we have developed a high-performance liquid chromatographic (HPLC) assay. The method uses 0.5 mL plasma, is linear to 10 mg/L and had a detection limit of 0.2 mg/L. Thalidomide in plasma specimens was unstable at physiological pH but could be stabilized for several weeks by simple acidification. We describe a protocol for monitoring patients treated with thalidomide which permits convenient transportation and storage of specimens and report, provisionally, that plasma concentrations in the range 1-7 mg/L are therapeutically effective in chronic graft-versus-host disease without adverse side effects.

The structure of avian eye lens delta-crystallin reveals a new fold for a superfamily of oligomeric enzymes

The crystal structure of turkey delta-crystallin, a principal soluble components of the avian lens, has been determined to a resolution of 2.5 A. It is a tetramer, of 200,000 M(r), with 222 symmetry. The subunit has a new fold composed of three mainly alpha-helical domains. One domain is a bundle of five long helices which forms a 20-helix bundle at the core of the tetramer. delta-crystallin shares approximately 90% sequence identity with the enzyme argininosuccinate lyase (EC 4.3.2.1), indicating that it is an example of a 'hijacked' enzyme. It is also distantly related to the class II fumarases, aspartases, adenylosuccinases and 3-carboxy-cis,cis-muconate lactonising enzyme. The structure reveals a putative active-site cleft which is located on the boundary between three subunits of the tetramer. This is the first three-dimensional structure of a representative of this superfamily of enzymes.

Major incident planning in South East Thames Region: a survey of medical staff awareness and training

In order to assess awareness and training of medical staff in major incident planning and disaster medicine, a telephone survey was conducted throughout South East Thames Region. Duty consultants and trainees in anaesthesia, general surgery and orthopaedic surgery from a total of 17 hospitals in the region were included. Accident and emergency (A&E) consultants were also interviewed in order to assess administrative aspects of major incident planning. It was found that major incident plans were updated regularly in all the hospitals that were surveyed. Training exercises had been held in 88% of hospitals and the majority had tested communications only. All consultants and 77% of trainees knew that their hospital had a major incident plan. However, only 39% of trainees had been given any major incident plan related literature and less than a third of all staff had attended a major incident plan orientation session. Over half of all staff expressed confidence in their personal training in disaster medicine, but few had received relevant tuition. Of all non-A&E personnel, 5% had attended an Advanced Trauma Life Support (ATLS) provider course. We conclude that major incident plans are in place and are updated in all the hospitals surveyed. However, all staff lack training in clinical and administrative aspects of major incident planning and disaster medicine. Recommendations to improve this situation are made.

Vasovasostomy: 10 years' experience in a district general hospital showing improved results with luminal dilatation

We report a simple and effective technique for vasovasostomy. Over 105 procedures have been performed over a 10-year period by a single consultant and his registrars with results comparable to those obtained with more time-consuming formal microsurgical techniques when routine luminal dilatation of the vas was adopted. Additionally, the chances of success were found to be greater the shorter the interval between vasectomy and vasovasostomy.

A comparison of three quality of life instruments in subjects with angina pectoris: the Sickness Impact Profile, the Nottingham Health Profile, and the Quality of Well Being Scale

Three instruments for the assessment of quality of life, the Quality of Well Being index (QWB), the Nottingham Health Profile (NHP) and the Sickness Impact Profile (SIP) were assessed in 59 patients with angina pectoris. The NHP showed increased statistically significant impairment with higher New York Heart Association (NYHA) class in 4 out of 6 subscales but not in single responses to questions on daily life. In the SIP 9 out of 11 dimensions increased with NYHA grade as did the physical and psychosocial subscores and the total score. There were statistically significant increases in six of the eleven dimensions. In the QWB an increase was observed only for two out of four categories employed in this instrument. The QWB was the most difficult to administer and thought likely to be insensitive to changes in anginal pain. There was a high level of agreement in similar dimensions of NHP and SIP. A psychological distress score was evaluated using the Symptom Rating Test and correlated with all summary dimensions of both instruments. The coefficients of variation were lower in SIP than in NHP categories. In conclusion quality of life instruments like NHP and SIP may be able to identify treatment effects in angina patients and so yield a useful addition to the traditional measures employed for the assessment of their condition.

Psychiatric disorder and disability in New Zealand long-stay psychiatric patients

A study was undertaken of the prevalence of physical disease, psychiatric disorder and deviant behaviour in a sample of 137 long stay psychiatric patients at Porirua Hospital near Wellington, New Zealand. Patients were in the main male, single, middle-aged to elderly and of European descent. Schizophrenia was the most common diagnosis. Psychiatric symptoms were moderately severe, the most common being unusual mannerisms and posturing, anxiety, blunted affect, tension, unusual thought content and somatic concerns. Known physical disorders were present in 66 patients. Levels of neuroleptic medication were high and tardive dyskinesia was observed in almost 60% of patients. Frequency of deviant behaviour was low in absolute terms but nonetheless problematic. The frequency of deviant behaviour was similar to those reported for British patients.

Subcutaneous alveolar soft-part sarcoma mimicking metastatic hypernephroma

Alveolar soft-part sarcoma represents a rare tumor of the subcutaneous and soft tissues that may present to the dermatologist. It may mimic both other primary tumours and other metastatic tumours. This mimicry has not been emphasised in the previous literature.

Motifs involved in protein-protein interactions

Interactions between proteins are extremely variable. However, in the dimeric proteins comprised of regular motifs, interface interactions are similar to those that stabilize monomers. Additional stability is gained by converting loops within motifs or domains to linkers across interfaces. In multi-domain proteins, interactions can be greatly effected by the conformation of linkers between domains. Complex association of subunits, involving higher rotational symmetry or cubic symmetry, frequently involves motif sharing across interfaces.

Induction of immunopotentiation activity by a protein-bound polysaccharide, PSK (review)

A protein-bound polysaccharide, PSK, extracted from the mycelium of Coriolus versicolor (Fr.) Quel, has been recognized for its host-mediated induction of antitumor and antimicrobial activities in mice. Intravenous administration of PSK, in association with OK-432 (Picibanil), transiently induced endogenous production of a cytotoxic factor (CF) (possibly tumor necrosis factor, TNF) in normal mice. The ability to produce CF depended greatly on both dose and interval between administration of the PSK and OK-432. Although PSK has been reported to contain several active ingredients, unfractionated PSK has been used in almost all experiments performed so far. We recently reported that, of the four subfractions separated by successive filtration through membrane filters, only the highest molecular weight fraction F4 (MW greater than 200 kD) induced significant antimicrobial activity in mice. PSK stimulated the NBT-reducing activity of mouse peritoneal macrophages and the iodination (incorporation of radioactive iodine into an acid-insoluble fraction) of human peripheral blood polymorphonuclear cells (PMN). Among the subfractions of PSK, the highest molecular weight fraction F4, and the fraction precipitated at pH 4.0-4.5 (Fr. 4), stimulated macrophage NBT-reducing activity and PMN iodination most. In contrast, natural and chemically modified glucans had little or no stimulating activity. PSK, F4 or Fr. 4 additively or synergistically stimulated TNF-induced cytotoxicity against L-929 cells, differentiation of human myelogenous leukemia cell lines toward monocytes/macrophages, and iodination of human peripheral blood PMN. The active PSK subfractions significantly reduced the down regulation of specific 125I-TNF or 125I-IFN-gamma binding to cellular receptors. These data suggest that (i) immunopotentiation activity of PSK might be ascribed, at least in part, to stimulation of cytokine action and production, and (ii) PSK might have some unique structural features.

Antitumor, antiviral and immunopotentiating activities of pine cone extracts: potential medicinal efficacy of natural and synthetic lignin-related materials (review)

Several antitumor substances that effectively inhibited the growth of ascites and solid tumor cells transplanted in mice were isolated from pine cone NaOH extract by acid- and ethanol-precipitation. These antitumor substances were also potent antiviral agents against human immunodeficiency virus, herpes simplex virus and influenza virus; they induced antimicrobial activity against Staphylococcal aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Candida albicans, and induced antiparasite activity against Hymenolepis nana in mice. Chemical analysis of these substances by IR, UV, NMR, ESR and partition chromatography on cellulose-TLC plate disclosed that they had lignin-related structures complexed with sugars or polysaccharides. Chlorinated decomposition of the lignin portion significantly reduced their antiviral activity. In agreement with this, the antiviral activity of synthesized lignins prepared by polymerization of phenylpropanoid precursors was comparable to that of the undecomposed counterparts of the pine cone extract. Acid hydrolysis of the polysaccharide portion significantly reduced the ability of the substances to induce antitumor and antimicrobial activities in mice. With an appropriate eliciting agent, intravenous administration of natural lignified substances transiently induced endogenous production of a cytotoxic factor (possibly tumor necrosis factor) in normal mice. Their priming activity was significantly higher than that of their component units or degradation products. These data suggest the importance of conjugating lignins with polysaccharides for in vivo expression of various kinds of immunopotentiating activity. As possible explanations for their induction of a variety of immunopotentiating activities, these natural and synthetic lignins stimulated macrophage NBT-reducing activity, polymorphonuclear cell (PMN) iodination and splenocyte DNA synthesis and inhibited poly (ADP-ribose) glycohydrolase, RNA-dependent DNA polymerase (reverse transcriptase) and RNA-dependent RNA polymerase activities.

Hepatic drug metabolism is increased in poorly controlled insulin-dependent diabetes mellitus

In addition to increased glycosylation of hemoglobin, abnormalities of other heme proteins such as cytochrome P-450 might also occur in patients with insulin-dependent diabetes mellitus. Antipyrine is a useful marker drug for cytochrome P-450 dependent hepatic drug metabolism. Antipyrine kinetics and urinary excretion of antipyrine metabolites were measured in 14 patients with insulin-dependent diabetes mellitus in poor metabolic control. Improvement in diabetic control in 9 patients, as measured by more normal HbA1 values, led to normalization of plasma antipyrine half-time (t1/2) and metabolism: the mean antipyrine t1/2 slowed from 4.7 +/- 0.2 (SEM) initially to 7.8 +/- 0.3 h in these 9 patients and was thus nearly identical to that of normal subjects 8.6 +/- 1.0. Antipyrine plasma clearance improved in the 9 diabetic patients whose diabetic control improved. The apparent volume of distribution was normal on both occasions in the diabetic patients. These findings provide a new argument for tight metabolic control in patients with insulin-dependent diabetes mellitus.

Asthma and chronic airflow limitation in the highlands of Papua New Guinea: low prevalence of asthma in the Asaro Valley

The prevalence of asthma in the South Fore region of Papua New Guinea was found to be 7.3%, which is thought exceptionally high for highland areas in this country. To investigate the prevalence of asthma and of chronic airflow limitation in a different highland region with similar living conditions, adults and children from 7 villages in the Asaro Valley were interviewed. Questions were asked about smoking history and about past and present symptoms of cough, of shortness of breath, of chest tightness and of asthma. Of 743 adults interviewed, 206 underwent a clinical study with measurements of lung function, bronchial responsiveness and skin prick tests. Dust was collected from the floors and blankets of 36 houses for counts of house dust mites. We did not find any children with symptoms of asthma. Only 2 adults (0.3%) had symptoms consistent with asthma, and a further 6.2% had symptoms and/or lung function consistent with chronic airflow limitation. Most bronchial hyperresponsiveness was associated with asthma or with chronic airflow limitation. The prevalence of atopy was similar in the Asaro and South Fore populations, but the South Fore had higher house dust mite counts in blanket dust. The low prevalence of asthma in the Asaro Valley is unexplained in terms of factors normally associated with asthma. Because asthma in this area does not appear in childhood and only develops in a small proportion of adults, it may be of different aetiology to asthma in Caucasian populations.

Asthma and chronic airflow limitation in the highlands of Papua New Guinea: low prevalence of asthma in the Asaro Valley

The prevalence of asthma in the South Fore region of Papua New Guinea was found to be 7.3%, which is thought exceptionally high for highland areas in this country. To investigate the prevalence of asthma and of chronic airflow limitation in a different highland region with similar living conditions, adults and children from 7 villages in the Asaro Valley were interviewed. Questions were asked about smoking history and about past and present symptoms of cough, of shortness of breath, of chest tightness and of asthma. Of 743 adults interviewed, 206 underwent a clinical study with measurements of lung function, bronchial responsiveness and skin prick tests. Dust was collected from the floors and blankets of 36 houses for counts of house dust mites. We did not find any children with symptoms of asthma. Only 2 adults (0.3%) had symptoms consistent with asthma, and a further 6.2% had symptoms and/or lung function consistent with chronic airflow limitation. Most bronchial hyperresponsiveness was associated with asthma or with chronic airflow limitation. The prevalence of atopy was similar in the Asaro and South Fore populations, but the South Fore had higher house dust mite counts in blanket dust. The low prevalence of asthma in the Asaro Valley is unexplained in terms of factors normally associated with asthma. Because asthma in this area does not appear in childhood and only develops in a small proportion of adults, it may be of different aetiology to asthma in Caucasian populations.

Expression of the vitronectin receptor during embryonic development; an immunohistological study of the ontogeny of the osteoclast in the rabbit

The development of the osteoclast during embryogenesis was studied in the rabbit by immunohistological techniques. Two monoclonal antibodies, 13C2 and 23C6, which react with the alpha-chain of the vitronectin receptor were used to define mono and multi-nucleate osteoclasts; being unreactive with other haemopoietic cells these antibodies could discriminate between osteoclasts and cells of the mononuclear phagocyte system. Staged rabbit embryos, from 14 to 28 days of age, were analysed and compared with findings from newborn and adult rabbits. No 13C2/23C6 immunoreactivity was seen in any of the tissues studied prior to day 17. 13C2/23C6-positive, mononuclear cells--presumptive osteoclast precursors--were first observed in the outer perichondrium of long-bones adjacent to the zone of hypertrophic cartilage in day 17 embryos. From day 17 onwards mono and multi-nucleate cells accumulated progressively in the perichondrium/periosteum, and by day 22 within the developing bone marrow cavity attached to bone spicules. No cells expressing the vitronectin receptor were seen at sites of embryonic or foetal haemopoiesis in yolk sac or foetal liver, that is, prior to the formation of the marrow cavity. Macrophages, defined by cross-reactivity with an antibody to human HLA-DR, first appeared in developing marrow spaces 11 days after the first osteoclast precursor appeared, suggesting that osteoclasts and definitive macrophages might develop from separate cell lineages, or that they diverge at an early stage of differentiation of haemopoietic stem cells.