Sickle cell disease in Australia: a snapshot from the Australian Haemoglobinopathy Registry

BACKGROUND

Sickle cell disease (SCD) is the most common monogenic disorder worldwide. In deoxygenated conditions, the altered beta chain (haemoglobin S [HbS]) polymerises and distorts the erythrocyte, resulting in pain crises, vasculopathy and end-organ damage. Clinical complications of SCD cause substantial morbidity, and therapy demands expertise and resources. Optimising care for patients and planning resource allocation for the future requires an understanding of the disease in the Australian population. The Australian Haemoglobinopathy Registry (HbR) is a collaborative initiative of specialist centres collating and analysing data on patients with haemoglobin disorders.

AIMS

To provide a snapshot of SCD in Australia over a 12-month period based on data from the HbR.

METHODS

Patients with a clinically significant sickling disorder across 12 clinical sites were included for analysis. Data include demographic and diagnostic details, as well as details of the clinical management of the condition over a 12-month period.

RESULTS

Data on 359 SCD patients demonstrate a shift in the demographic of patients in Australia, with a growing proportion of sub-Saharan African ethnicities associated with the HbSS genotype. Acute and chronic complications are common, and patients require significant outpatient and inpatient support. Prevalence of disease complications and therapeutic trends are in keeping with other high-income countries.

CONCLUSIONS

This study provides the first national picture of SCD in Australia, describing the characteristics and needs of SCD patients, elucidating demand for current and novel therapy and facilitating the planning of services for this vulnerable population.

Glycaemic outcomes in Australasian children and adults with type 1 diabetes: failure to meet targets across the age spectrum

BACKGROUND

The goal of therapy in type 1 diabetes (T1D) is to achieve optimal glycaemic targets and reduce complications. Robust data representing glycaemic outcomes across the lifespan are lacking in Australasia.

AIMS

To examine contemporary glycaemic outcomes and rate of use of diabetes technologies in Australasian people with T1D.

METHODS

Cross-sectional analysis of de-identified data from 18 diabetes centres maintained in the Australasian Diabetes Data Network registry during 2019. Glycaemia was measured using glycated haemoglobin (HbA1c). The proportion of people with T1D achieving the international HbA1c target of <53 mmol/mol (7%) was calculated. Rates of continuous subcutaneous insulin infusion (CSII) and continuous glucose monitoring (CGM) use were determined.

RESULTS

A total of 7988 individuals with T1D with 30 575 visits were recorded in the registry. The median (interquartile range) age was 15.3 (10.0) years and diabetes duration was 5.7 (9.4) years with 49% on multiple daily injections (MDI) and 36% on CSII. The mean HbA1c for the whole cohort was 66 mmol/mol (8.2%). HbA1c increased with age, from 60 mmol/mol (7.6%) in children <10 years, increasing during adolescence and peaking at 73 mmol/mol (8.8%) in the 20-25 years age group. The HbA1c target of <53 mmol/mol (7%) was met in 18% of children and 13% of adults. HbA1c was lower on CSII as compared with those on MDI (P < 0.0001).

CONCLUSIONS

Only a minority of children and adults achieve the recommended glycaemic goals despite access to specialist care in major diabetes centres. There is a need to identify factors that improve glycaemic outcomes.

Diabetic Ketoacidosis at Onset of Type 1 Diabetes and Long-term HbA1c in 7,961 Children and Young Adults in the Australasian Diabetes Data Network

OBJECTIVE

The relationship between diabetic ketoacidosis (DKA) at diagnosis of type 1 diabetes and long-term glycemic control varies between studies. We aimed, firstly, to characterize the association of DKA and its severity with long-term HbA1c in a large contemporary cohort, and secondly, to identify other independent determinants of long-term HbA1c.

RESEARCH DESIGN AND METHODS

Participants were 7,961 children and young adults diagnosed with type 1 diabetes by age 30 years from 2000 to 2019 and followed prospectively in the Australasian Diabetes Data Network (ADDN) until 31 December 2020. Linear mixed-effect models related variables to HbA1c.

RESULTS

DKA at diagnosis was present in 2,647 participants (33.2%). Over a median 5.6 (interquartile range 3.2, 9.4) years of follow-up, participants with severe, but not moderate or mild, DKA at diagnosis had a higher mean HbA1c (+0.23%, 95% CI 0.11,0.28; [+2.5 mmol/mol, 95% CI 1.4,3.6]; P < 0.001) compared with those without DKA. Use of continuous subcutaneous insulin infusion (CSII) was independently associated with a lower HbA1c (-0.28%, 95% CI -0.31, -0.25; [-3.1 mmol/mol, 95% CI -3.4, -2.8]; P < 0.001) than multiple daily injections, and CSII use interacted with severe DKA to lower predicted HbA1c. Indigenous status was associated with higher HbA1c (+1.37%, 95% CI 1.15, 1.59; [+15.0 mmol/mol, 95% CI 12.6, 17.4]; P < 0.001), as was residing in postcodes of lower socioeconomic status (most vs. least disadvantaged quintile +0.43%, 95% CI 0.34, 0.52; [+4.7 mmol/mol, 95% CI 3.4, 5.6]; P < 0.001).

CONCLUSIONS

Severe, but not mild or moderate, DKA at diagnosis was associated with a marginally higher HbA1c over time, an effect that was modified by use of CSII. Indigenous status and lower socioeconomic status were independently associated with higher long-term HbA1c.

Universal Subsidized Continuous Glucose Monitoring Funding for Young People With Type 1 Diabetes: Uptake and Outcomes Over 2 Years, a Population-Based Study

OBJECTIVE

Continuous glucose monitoring (CGM) is increasingly used in type 1 diabetes management; however, funding models vary. This study determined the uptake rate and glycemic outcomes following a change in national health policy to introduce universal subsidized CGM funding for people with type 1 diabetes aged <21 years.

RESEARCH DESIGN AND METHODS

Longitudinal data from 12 months before the subsidy until 24 months after were analyzed. Measures and outcomes included age, diabetes duration, HbA1c, episodes of diabetic ketoacidosis and severe hypoglycemia, insulin regimen, CGM uptake, and percentage CGM use. Two data sources were used: the Australasian Diabetes Database Network (ADDN) registry (a prospective diabetes database) and the National Diabetes Service Scheme (NDSS) registry that includes almost all individuals with type 1 diabetes nationally.

RESULTS

CGM uptake increased from 5% presubsidy to 79% after 2 years. After CGM introduction, the odds ratio (OR) of achieving the HbA1c target of <7.0% improved at 12 months (OR 2.5, P < 0.001) and was maintained at 24 months (OR 2.3, P < 0.001). The OR for suboptimal glycemic control (HbA1c ≥9.0%) decreased to 0.34 (P < 0.001) at 24 months. Of CGM users, 65% used CGM >75% of time, and had a lower HbA1c at 24 months compared with those with usage <25% (7.8 ± 1.3% vs. 8.6 ± 1.8%, respectively, P < 0.001). Diabetic ketoacidosis was also reduced in this group (incidence rate ratio 0.49, 95% CI 0.33-0.74, P < 0.001).

CONCLUSIONS

Following the national subsidy, CGM use was high and associated with sustained improvement in glycemic control. This information will inform economic analyses and future policy and serve as a model of evaluation diabetes technologies.

Determinants of Cardiovascular Risk in 7000 Youth With Type 1 Diabetes in the Australasian Diabetes Data Network

CONTEXT

Cardiovascular disease occurs prematurely in type 1 diabetes. The additional risk of overweight is not well characterized.

OBJECTIVE

The primary aim was to measure the impact of body mass index (BMI) in youth with type 1 diabetes on cardiovascular risk factors. The secondary aim was to identify other determinants of cardiovascular risk.

DESIGN

Observational longitudinal study of 7061 youth with type 1 diabetes followed for median 7.3 (interquartile range [IQR] 4-11) years over 41 (IQR 29-56) visits until March 2019.

SETTING

15 tertiary care diabetes centers in the Australasian Diabetes Data Network.Participants were aged 2 to 25 years at baseline, with at least 2 measurements of BMI and blood pressure.

MAIN OUTCOME MEASURE

Standardized systolic and diastolic blood pressure scores and non-high-density lipoprotein (HDL) cholesterol were co-primary outcomes. Urinary albumin/creatinine ratio was the secondary outcome.

RESULTS

BMI z-score related independently to standardized blood pressure z- scores and non-HDL cholesterol. An increase in 1 BMI z-score related to an average increase in systolic/diastolic blood pressure of 3.8/1.4 mmHg and an increase in non-HDL cholesterol (coefficient + 0.16 mmol/L, 95% confidence interval [CI], 0.13-0.18; P < 0.001) and in low-density lipoprotein (LDL) cholesterol. Females had higher blood pressure z-scores, higher non-HDL and LDL cholesterol, and higher urinary albumin/creatinine than males. Indigenous youth had markedly higher urinary albumin/creatinine (coefficient + 2.15 mg/mmol, 95% CI, 1.27-3.03; P < 0.001) and higher non-HDL cholesterol than non-Indigenous youth. Continuous subcutaneous insulin infusion was associated independently with lower non-HDL cholesterol and lower urinary albumin/creatinine.

CONCLUSIONS

BMI had a modest independent effect on cardiovascular risk. Females and Indigenous Australians in particular had a more adverse risk profile.

0143 Vigilance Declines Following Sleep Deprivation are Associated with Two Previously Identified Dynamic Connectivity States

Introduction

Dynamic functional connectivity (DFC) analysis of resting-state fMRI data has been successfully used to track fluctuations in arousal in the human brain. Changes in DFC have also been reported with acute sleep deprivation. Here, we demonstrate that dynamic connectivity states (DCS) previously related to arousal are reproducible, and are associated with individual differences in sustained attention declines after one night of total sleep deprivation.

Methods

32 participants underwent two counterbalanced resting-state fMRI scans: during rested wakefulness (RW) and following total sleep deprivation (SD). They also completed the Psychomotor Vigilance Test (PVT), a sustained attention task that is highly sensitive to the effects of sleep loss. SD vulnerability was computed as the decrease in response speed (∆RS) and increase in lapses (∆lapse) in SD compared with RW.

Dynamic functional connectivity analysis was conducted on rs-fMRI data. Connectivity matrices were clustered to obtain 5 prototypical DCS. We calculated the proportion of time participants spent in each of these DCS, as well as how often participants transitioned between DCSs. Relationships between SD vulnerability and connectivity metrics were then correlated.

Results

We recovered two DCS that were highly similar (ρ = .89-.91) to arousal-related DCS observed in previous work (high arousal state (HAS); low arousal state (LAS)).

After sleep deprivation, the proportion of time spent in the LAS increased significantly (t29=3.16, p=.0039), while there was no significant change in HAS (t29=-1.43, p=.16). We observed significantly more state transitions in RW compared with SD. Change in LAS and HAS across sleep conditions correlated significantly with SD vulnerability (ΔLASxΔRS: r=-0.64, p&lt;.0001; ΔLASxΔlapse: r=0.43, p=.018; ΔHASxΔRS; r=0.43, p=.019; ΔHASxΔlapse; r=-0.39, p=.033). Finally, Δ%transitions was correlated with ΔRS but not Δlapse.

Conclusion

This study adds to the evidence that two specific reproducible DCS are robust markers of arousal and attention, and may be useful indicators of SD vulnerability.

Support

This work was supported by the National Medical Research Council, Singapore (STaR/0015/2013), and the National Research Foundation Science of Learning (NRF2016-SOL002-001).

Prehospital notification for major trauma patients requiring emergency hospital transport: A systematic review

OBJECTIVE

This systematic review aimed to determine the effect of prehospital notification systems for major trauma patients on overall (<30 days) and early (<24 hours) mortality, hospital reception, and trauma team presence (or equivalent) on arrival, time to critical interventions, and length of hospital stay.

METHODS

Experimental and observational studies of prehospital notification compared with no notification or another type of notification in major trauma patients requiring emergency transport were included. Risk of bias was assessed using the Cochrane ACROBAT-NRSI tool. A narrative synthesis was conducted and evidence quality rated using the GRADE criteria.

RESULTS

Three observational studies of 72,423 major trauma patients were included. All were conducted in high-income countries in hospitals with established trauma services, with two studies undertaking retrospective analysis of registry data. Two studies reported overall mortality, one demonstrating a reduction in mortality; (adjusted odds ratio (OR) 0.61, 95% confidence interval (CI) 0.39 to 0.94, 72,073 participants); and the other demonstrating a nonsignificant change (OR 0.61, 95% CI 0.23 to 1.64, 81 participants). The quality of this evidence was rated as very low.

CONCLUSION

Limited research on the topic constrains conclusive evidence on the effect of prehospital notification on patient-centered outcomes after severe trauma. Composite interventions that combine prehospital notification with effective actions on arrival to hospital such as trauma bay availability, trauma team presence, and early access to definitive management may provide more robust evidence towards benefits of early interventions during trauma reception and resuscitation.

Overlap and dissociation of semantic processing of Chinese characters, English words, and pictures: evidence from fMRI

The functional anatomy of Chinese character processing was investigated using fMRI. Right-handed Mandarin-English bilingual participants made either semantic or perceptual size judgements with characters and pictures. Areas jointly activated by character and picture semantic tasks compared to size judgement tasks included the left prefrontal region (BA 9, 44, 45), left posterior temporal, left fusiform, and left parietal regions. Character processing produced greater activation than picture processing in the left mid and posterior temporal as well as left prefrontal regions. The lateral occipital regions were more active during picture semantic processing than character semantic processing. A similar pattern of activation and contrasts was observed when English words and pictures were compared in another set of bilingual participants. However, there was less contrast between word and picture semantic processing than between character and picture processing in the left prefrontal region. When character and word semantic processing were compared directly in a third group, the loci of activation peaks was similar in both languages but Chinese character semantic processing was associated with a larger MR signal change. The semantic processing of Chinese characters, English words, and pictures activates a common semantic system within which there are modality-specific differences. The semantic processing of Chinese characters more closely resembles English words than pictures.

A novel method for determining linkage between DNA sequences: hybridization to paired probe arrays

Cooperative hybridization has been used to establish physical linkage between two loci on a DNA strand. Linkage was detected by hybridization to a new type of high-density oligonucleotide array. Each synthesis location on the array contains a mixture of two different probe sequences. Each of the two probes can hybridize independently to a different target sequence, but if the two target sequences are physically linked there is a cooperative increase in hybridization yield. The ability to create and control non-linear effects raises a host of possibilities for applications of oligonucleotide array hybridization. The method has been used to assign linkage in 50:50 mixtures of DNA containing single nucleotide polymorphisms (SNPs) separated by 17, 693, 1350 and 2038 bp and to reconstruct haplotypes. Other potential uses include increasing the specificity of hybridization in mutation detection and gene expression monitoring applications, determining SNP haplotypes, characterizing repetitive sequences, such as short tandem repeats, and aiding contig assembly in sequen-cing by hybridization.

Large-scale identification, mapping, and genotyping of single-nucleotide polymorphisms in the human genome

Single-nucleotide polymorphisms (SNPs) are the most frequent type of variation in the human genome, and they provide powerful tools for a variety of medical genetic studies. In a large-scale survey for SNPs, 2.3 megabases of human genomic DNA was examined by a combination of gel-based sequencing and high-density variation-detection DNA chips. A total of 3241 candidate SNPs were identified. A genetic map was constructed showing the location of 2227 of these SNPs. Prototype genotyping chips were developed that allow simultaneous genotyping of 500 SNPs. The results provide a characterization of human diversity at the nucleotide level and demonstrate the feasibility of large-scale identification of human SNPs.

Genetic content and preliminary transcriptional analysis of a representative region of murine gammaherpesvirus 68

Murine gammaherpesvirus 68 (MHV-68) is a relatively recently discovered pathogen of wild rodents and provides a unique opportunity to explore in detail the interactions of a gammaherpesvirus with its natural host. It may also provide a much needed small animal model for human gammaherpesviruses. As a step in the detailed analysis of virus gene structure and expression we have sequenced over 20 kb of the MHV-68 genome and mapped gene transcripts by Northern blot hybridization. The region we chose to analyse contains several conserved gene blocks as well as some less well conserved genes and allowed us to estimate the relationship of this virus to other herpesvirus family members. Of particular interest is the fact that none of the characteristic Epstein-Barr virus (EBV) genes is present at this genomic locus although MHV-68 does have one gene encoding a membrane glycoprotein, 9p150, which shows similarities to the major membrane glycoprotein of EBV. Our results further confirm that MHV-68 is a gammaherpesvirus marginally more closely related to a cluster of gammaherpesviruses including herpesvirus salmiri than to EBV. Northern analysis shows that the temporal regulation of expression is broadly similar to that of other herpesviruses in this region of the genome. We also show that like other gammaherpesviruses, MHV-68 splices its homologue of the EBV transcriptional activator gene BMRF1.

Nucleotide sequence analysis of the human KCNJ1 potassium channel locus

Detailed analyses of transcripts encoding various isoforms of the human potassium (K+, inward rectifying) channel ROM-K (also referred to as K(ir)1.1) revealed the existence of at least five distinct transcripts [Shuck et al., J. Biol. Chem. 269 (1994) 24261-24270]. These five hROM-K transcripts appear to be the result of alternative splicing of five exons. The nucleotide sequence of the genomic DNA including and spanning these exons (the KCNJ1 locus) was obtained directly from lambda and P1 clones (a total of 40 kb). The organization of the hKCNJ1 gene was determined by combining this sequence information with data obtained from primer extension and RT-PCR experiments. It appears that the hKCNJ1 gene utilizes multiple promoters, with promoter-like elements found 5' of exons 1, 4, or 5. The promoter 5' of exon 5 was unexpected; thus, it appears that the hKCNJ1 gene is capable of producing six distinct hROM-K transcripts via the use of three promoters and alternative splicing of five exons. Comparisons of the rat and human ROM-K cDNA sequences find human homologs (orthologs) for two of the three distinct rROM-K transcripts. A search of the complete human KCNJ1 sequence with the exon sequence that defines the other rROM-K transcript located a region of shared nucleotides, a putative sixth exon, in the hKCNJ1 gene. This finding suggests that the rKCNJ1 gene may contain an exon that is no longer or infrequently used in transcripts derived from the hKCNJ1 gene.

Accessing genetic information with high-density DNA arrays

Rapid access to genetic information is central to the revolution taking place in molecular genetics. The simultaneous analysis of the entire human mitochondrial genome is described here. DNA arrays containing up to 135,000 probes complementary to the 16.6-kilobase human mitochondrial genome were generated by light-directed chemical synthesis. A two-color labeling scheme was developed that allows simultaneous comparison of a polymorphic target to a reference DNA or RNA. Complete hybridization patterns were revealed in a matter of minutes. Sequence polymorphisms were detected with single-base resolution and unprecedented efficiency. The methods described are generic and can be used to address a variety of questions in molecular genetics including gene expression, genetic linkage, and genetic variability.

Extensive polymorphisms observed in HIV-1 clade B protease gene using high-density oligonucleotide arrays

Naturally occurring mutations in HIV-1-infected patients have important implications for therapy and the outcome of clinical studies. However, little is known about the prevalence of mutations that confer resistance to HIV-1 protease inhibitors in isolates derived from patients naive for such inhibitors. In the first clinical application of high-density oligonucleotide array sequencing, the sequences of 167 viral isolates from 102 patients have been determined. The DNA sequence of USA HIV-1 clade B proteases was found to be extremely variable and 47.5% of the 99 amino acid positions varied. This level of amino acid diversity is greater than that previously known for all worldwide HIV-1 clades combined (40%). Many of the amino acid changes that are known to contribute to drug resistance occurred as natural polymorphisms in isolates from patients who had never received protease inhibitors.

Using oligonucleotide probe arrays to access genetic diversity

As the Human Genome Project and related efforts identify and determine the DNA sequences of human genes, it is important that highly reliable and efficient mechanisms are found to access individual genetic variation. It is only through a greater understanding of genetic diversity that the true benefit of the Human Genome Project will be realized. One approach, hybridization to high-density arrays of oligonucleotides, is a fast and effective means of accessing this genetic variation. Light-directed chemical synthesis has been used to generate miniaturized, high-density arrays of oligonucleotide probes. Application-specific oligonucleotide probe array designs have been developed for the rapid screening of characterized genes. Dedicated instrumentation and software have been developed for array hybridization, fluorescence detection and data acquisition and analysis. In a specific and challenging application, oligonucleotide probe arrays have been used to screen the reverse transcriptase and protease genes of the highly polymorphic HIV-1 genome to explore genetic diversity and detect mutations conferring resistance to antiviral drugs. Results from this application strongly suggest that oligonucleotide probe arrays will be a powerful tool for rapid investigations in sequence checking, pathogen detection, expression monitoring and DNA molecular recognition.

Negative behavior during marital conflict is associated with immunological down-regulation

Although increased morbidity and mortality have been reliably associated with social isolation and less satisfying personal relationships, relatively little is known about the underlying biopsychosocial mechanisms. We assessed problem-solving behaviors and changes in immune function in 90 newlywed couples who were admitted to a hospital research unit for 24 hours. Subjects who exhibited more negative or hostile behaviors during a 30-minute discussion of marital problems showed greater decrements over 24 hours relative to low negative subjects on four functional immunological assays (natural killer cell lysis, blastogenic response to two mitogens, and the proliferative response to a monoclonal antibody to the T3 receptor), as well as larger increases in the numbers of total T lymphocytes and helper T lymphocytes. High negative subjects had higher antibody titers to latent Epstein-Barr virus than low negative subjects, consistent with down-regulated immune function. Women were more likely to show negative immunological changes than men. The discussion of marital problems also led to larger increases in blood pressure that remained elevated longer in high negative subjects than low negative subjects. Positive or supportive problem-solving behaviors were not related to either immunological or blood pressure changes. These physiological differences were particularly noteworthy because marital satisfaction was high in both groups, and couples had been selected on the basis of stringent mental and physical health criteria. These data provide additional support for the link between personal relationships and immune function.

Temporal lobe epilepsy in early childhood

To explore the electroclinical features of temporal lobe epilepsy (TLE) in early childhood, we studied results of video-EEG and other tests of 14 children aged 16 months to 12 years selected by seizure-free outcome after temporal lobectomy. Four children had mesiotemporal sclerosis, 1 had cortical dysplasia, and 9 had low-grade temporal neoplasms. The children had complex partial seizures (CPS) with symptomatology similar to that of adults with TLE, including decreased responsiveness and automatisms. Automatisms tended to be simpler in the younger children, typically limited to lip smacking and fumbling hand gestures. Scalp/sphenoidal EEG showed anterior/inferior temporal interictal sharp waves and unilateral temporal seizure onset in the 4 children with mesiotemporal sclerosis and in the child with cortical dysplasia, but EEG findings in 9 children with low-grade temporal tumors were complex, including multifocal interictal sharp waves or poorly localized or falsely lateralized EEG seizure onset. In children without tumors, video-EEG was critical to localization of the epileptogenic zone for resection, but in patients with tumors video-EEG was less localizing and its main value was to confirm that the reported behaviors were epileptic seizures with semiology typical of temporal lobe onset.

Epilepsy surgery in children and adults

Epilepsy surgery is now accepted as a treatment modality for medically intractable epilepsy. A careful and detailed evaluation of patients is required by a trained epilepsy team which includes neurosurgeons, neurologists, neuroradiologists, psychologists and psychiatrists. For intractable complex partial seizures of temporal lobe origin, epilepsy surgery offers an 80% success rate.

Enzymatic multiplex DNA sequencing

The problem of reading DNA sequence films has been reformulated using an easily implemented, multiplex version of enzymatic DNA sequencing. By utilizing a uniquely tagged primer for each base-specific sequencing reaction, the four reactions can be pooled and electrophoresed in a single lane. This approach has been previously proposed for use with fluorescently labelled probes (1), and is analogous to the principle used in four-dye fluorescence sequencing except that the signals are resolved following electrophoresis (2). After transfer to a nylon membrane, images are obtained separately for each of the four reactions by hybridization using oligonucleotide probes. The images can then be superimposed to reconstitute a complete sequence pattern. In this way the correction of gel distortion effects and accurate band registration are considerably simplified, as each of the four base-specific ladders require very similar corrections. The methods therefore provide the basis for a second generation of more accurate and reliable film reading programs, as well as being useful for conventional multiplex sequencing. Unlike the original multiplex protocol (3), the approach described is suitable for small projects, as multiple cloning vectors are not used. Although more than one vector can be utilized, only a library of fragments cloned into any single phage, phagemid or plasmid vector is actually required, together with a set of tagged oligonucleotide primers.

Focal seizure in non-ketotic hyperglycaemia

Structural brain lesions are the common causes of focal seizure. We report two patients who presented with focal fits with non-ketotic hyperglycaemia. There were no focal brain lesions to account for the fits. The fit of one patient was aborted by intravenous phenytoin while the other by controlling the blood sugar.

Herpesviruses: a study of parts

Dormancy, an adaptation to survival in a hostile environment, is a trait common to herpesviruses. Two other features are a large (0.1-0.25 Mb) and mutile (inherently easily mutable) genome. The complete nucleotide sequences of four herpesviruses have recently been determined. This database is unparalleled in allowing the comparative evolutionary study of a complex group of viruses in eukaryotes. In this article, we examine aspects of herpesvirus diversity in the light of recent studies which have revealed characteristics that unify the family at the genetic level.

Human herpesvirus 6 is closely related to human cytomegalovirus

A sequence of 21,858 base pairs from the genome of human herpesvirus 6 (HHV-6) strain U1102 is presented. The sequence has a mean composition of 41% G + C, and the observed frequency of CpG dinucleotides is close to that predicted from this mononucleotide composition. The sequence contains 17 complete open reading frames (ORFs) and part of another at the 5' end of the sequence. The predicted protein products of two of these ORFs have no recognizable homologs in the genomes of other sequenced human herpesviruses (i.e., Epstein-Barr virus [EBV], human cytomegalovirus [HCMV], herpes simplex virus [HSV], and varicella-zoster virus [VZV]). However, the products of nine other ORFs are clearly homologous to a set of genes that is conserved in all other sequenced herpesviruses, including homologs of the alkaline exonuclease, the phosphotransferase, the spliced ORF, and the major capsid protein genes. Measurements of similarity between these homologous sequences showed that HHV-6 is clearly most closely related to HCMV. The degree of relatedness between HHV-6 and HCMV was commensurate with that observed in comparisons between HSV and VZV or EBV and herpesvirus saimiri and significantly greater than its relatedness to EBV, HSV, or VZV. In addition, the gene for the major capsid protein and its 5' neighbor are reoriented with respect to the spliced ORFs in the genomes of both HHV-6 and HCMV relative to the organization observed in EBV, HSV, and VZV. Three ORFs in HHV-6 have recognizable homologs only in the genome of HCMV. Despite differences in gross composition and size, we conclude that the genomes of HHV-6 and HCMV are closely related.

Identification of the major capsid protein gene of human cytomegalovirus

The coding region for the major capsid protein (MCP) of human cytomegalovirus (HCMV) was identified by comparing the protein sequence with the respective sequences of herpes simplex virus (HSV), Epstein-Barr virus, and varicella-zoster virus. The predicted length of the HCMV MCP was 1,370 amino acids. Comparison of the MCP sequences of the different human herpesviruses showed a homology of 25% to the MCP of HSV type 1, a homology of 29% to the MCP of Epstein-Barr virus, and a homology of 23% to the MCP of varicella-zoster virus. A subfragment of the HSV type 1 KpnI i fragment encoding the MCP VP5 cross-hybridized with the HCMV HindIII U fragment containing part of the MCP gene. Northern (RNA) blot analyses with subclones out of the coding region for the HCMV MCP detected one large transcript of about 8 kilobases. A portion of the open reading frame was expressed in Escherichia coli plasmid pBD2 IC2OH as a beta-galactosidase fusion protein and was used to generate polyclonal antibodies in New Zealand White rabbits. The obtained antisera reacted in Western immunoblots with the MCP of purified HCMV virions. A monoclonal antibody against the human MCP and a monospecific rabbit antiserum against strain Colburn of simian cytomegalovirus detected the fusion protein as well as the MCP of purified virions in immunoblots.

Lung transplantation: better survival results after graft pretreatment with concanavalin A or chondroitin sulfate

Pretreatment of the lung graft with concanavalin A (Con A) or chondroitin sulfate (CIS) was used to modify the lung allograft response after transplantation into moderately immunosuppressed (low doses of azathioprine and prednisone) recipients. Significant (p less than 0.05) prolongation of survival was observed after graft pretreatment. Pneumonia and rejection were the most frequent causes of death for all groups of dogs. However, only 3 out of 6 animals from each of the groups with pretreated grafts died of pneumonia or rejection, whereas 5 of the 6 animals in the control group died of these causes. Furthermore, when rejection occurred in the dogs with lung grafts pretreated with Con A or CIS, it was considerably delayed compared with the controls. Partial pressure of arterial oxygen, chest roentgenograms, and lung histology were good indicators of lung viability after transplantation.

Hypothermic pulsatile perfusion: its use in the preservation of pancreases for 24 to 48 hours before islet cell transplantation

Canine pancreases underwent hypothermic pulsatile perfusion for 24 or 48 hours before islet cell collagenase digestion and intrasplenic autotransplantation. The numbers of dogs surviving longer than two months are as follows: dogs receiving pancreatectomies, 0/10; dogs receiving 24-hour-perfused islet cells, 6/10, dogs receiving 48-hour-perfused islet cells, 4/10; and dogs receiving fresh islet cells, 7/10. Islet cells from 48-hour-perfused pancreases were not as good in reversing hyperglycemia as the islet cells from 24-hour-perfused pancreases. Histologically, the islet cells appeared to be normal in the fresh and 24-hour-perfused pancreases. Thus, hypothermic pulsatile perfusion of pancreas autografts for 24 hours appears to be a safe and reliable method. When this technique is used clinically, special attention should be given to 48-hour-perfused pancreases because the reversal of hyperglycemia sometime is not complete.

Preservation of the pancreas for transplantation

Twenty-four hour hypothermic bloodless pulsatile perfusion of the canine pancreas did not have any detrimental effect on the survival rate of minimally immunosuppressed recipients. On the contrary, there was a favorable trend toward improved long term survival of perfused and transplanted pancreas. Fresh grafts or those stored under hypothermia survived for shorter periods of time than did the perfused grafts. Apancreatic dogs survived only for a few days after pancreatectomy. Hypothermic pulsatile perfusion appeared to be a better method of preservation than hypothermic storage of pancreatic allografts.

Effects of pulsatile perfusion pressure and storage on hearts preserved for 24 hours under hypothermia, for transplantation

Canine hearts preserved for 24 hours under hypothermic pulsatile perfusion at a systolic pressure of 25 mm Hg had better perfusion and transplantation survival results than hearts perfused at 50 or 80 mm Hg. Also, hearts perfused at a systolic pressure of 25 mm Hg did better than simple hypothermically stored hearts or fresh allografts. These findings indicate that hearts are adequately perfused for 24 hours under hypothermia for transplantation at a systolic pressure of 25 mm Hg.

Concanavalin a: modification of kidney graft immunogenicity in a double transplant model

This study determines the effectiveness of flush graft pretreatment with concanavalin A (Con A) in minimally immunosuppressed recipients receiving double kidney transplantation. Significant prolongation of survival was seen when both kidneys from the same unrelated donor were treated with Con A, when both kidneys from different unrelated donors were treated with Con A, or when the allogeneic kidney was treated with Con A, and the syngeneic kidney was untreated. There was no significant prolongation in kidney allograft survival when one of the two allogeneic kidneys was treated with Con A, whether they came from the same, or different donors. If only the syngeneic kidney was treated with Con A and no treatment was given to the allogeneic kidney, also no prolongation of survival was observed. Thus, this study fully agrees with previous data indicating that Con A is not acting by systemic immunosuppression, but by local changes that modify the kidney immunogenicity. The theoretical implications associated with the prolongation of graft survival after flush pretreatment with Con A are activation of suppressor T cells, enhancement, physico-chemical modifications of the cell membrane and/or others.

Preservation of canine hearts after warm ischemia (zero to thirty minutes) and one to two days of hypothermic storage. A comparative analysis of crystalloid and colloid solutions with different osmolarity and ion composition

The effect of extracellular crystalloid (Ringer's) and colloid (silica gel fraction [SGF]) solutions, and intracellular crystalloid (Sacks) and colloid (modified silica gel fraction [MSGF]) solutions for canine heart preservation in a 24 to 48 hour model of hypothermic storage and zero to 30 minutes of warm ischemia was compared. Canine hearts flushed with an intracellular colloid solution (MSGF) had better survival rates after transplantation than did the hearts flushed with intracellular crystalloid solutions (Sacks). Better survival results also were observed in the group of hearts flushed with extracellular colloid (SGF) solutions than extracellular crystalloid (Ringer's) solutions. The most important theoretical factor in heart preservation appears to be hyperosmolarity and elevated concentration of potassium, proteins, and glucose.