Global developmental delay and a de novo deletion of the 16p13.13 region

Many rare genetic variants are associated with the risk of atypical neurodevelopmental trajectories. In this study, we report a patient with developmental delay, autistic traits and multiple congenital anomalies, including congenital heart anomalies and orofacial cleft, with a 0.832 Mb de novo deletion of the 16p13.13 region classified as a variant of uncertain significance. Comparison of similar sized deletions and duplications overlapping the same genes in the DECIPHER database, revealed seven reports of copy number variants (CNVs), four duplications and three deletions. A neurodevelopmental phenotype including learning disability and intellectual disability was noted in some of the DECIPHER entries where phenotype was provided. Although the association between a deletion in this region and an atypical neurodevelopmental trajectory remains to be elucidated, the overlapping CNVs with neurodevelopmental phenotypes suggests possible candidate genes within the 16p13.13 region.

Support to caregivers who have received genetic information about neurodevelopmental and psychiatric vulnerability in their young children: A narrative review

Diagnosis of pathogenic genetic variants associated with neurodevelopmental and psychiatric disorders (NPDs) is increasingly made early in life. This narrative review focuses on the need for, and provision of, psychological supports following genetic diagnosis. We conducted a literature search of publications on how caregivers are informed about the NPD vulnerability associated with genetic variants, challenges and unmet needs when receiving this information, and whether psychological supports are provided. Given its early recognition, the 22q11.2 deletion has been studied thoroughly for two decades, providing generalizable insights. This literature indicates the complex caregivers' needs related to learning about potential NPD vulnerabilities associated with a genetic variant, include how to communicate the diagnosis, how to identify early signs of NPDs, how to deal with stigma and a lack of medical expertise outside of specialized genetics clinics. With one exception, no publications describe psychotherapeutic support provided to parents. In the absence of support, caregivers struggle with several unmet needs regarding potential longer-term NPD implications of a genetic diagnosis. The field needs to go beyond explaining genetic diagnoses and associated vulnerabilities, and develop approaches to support caregivers with communicating and managing NPD implications across the child's lifespan.

A multidisciplinary approach and consensus statement to establish standards of care for Angelman syndrome

BACKGROUND

Angelman syndrome (AS) is a rare neurogenetic disorder present in approximately 1/12,000 individuals and characterized by developmental delay, cognitive impairment, motor dysfunction, seizures, gastrointestinal concerns, and abnormal electroencephalographic background. AS is caused by absent expression of the paternally imprinted gene UBE3A in the central nervous system. Disparities in the management of AS are a major problem in preparing for precision therapies and occur even in patients with access to experts and recognized clinics. AS patients receive care based on collective provider experience due to limited evidence-based literature. We present a consensus statement and comprehensive literature review that proposes a standard of care practices for the management of AS at a critical time when therapeutics to alter the natural history of the disease are on the horizon.

METHODS

We compiled the key recognized clinical features of AS based on consensus from a team of specialists managing patients with AS. Working groups were established to address each focus area with committees comprised of providers who manage >5 individuals. Committees developed management guidelines for their area of expertise. These were compiled into a final document to provide a framework for standardizing management. Evidence from the medical literature was also comprehensively reviewed.

RESULTS

Areas covered by working groups in the consensus document include genetics, developmental medicine, psychology, general health concerns, neurology (including movement disorders), sleep, psychiatry, orthopedics, ophthalmology, communication, early intervention and therapies, and caregiver health. Working groups created frameworks, including flowcharts and tables, to help with quick access for providers. Data from the literature were incorporated to ensure providers had review of experiential versus evidence-based care guidelines.

CONCLUSION

Standards of care in the management of AS are keys to ensure optimal care at a critical time when new disease-modifying therapies are emerging. This document is a framework for providers of all familiarity levels.

The role of the behavior analyst on interprofessional mental health teams: opportunities for collaboration and enhancing patient care

Patients living with mental illness have needs that span a range of professional disciplines, settings, and service systems. These needs are best addressed through interprofessional collaboration. Behavior analysts can play a valuable role in enhancing patient care as part of the interprofessional mental health team. We provide information about the field of applied behavior analysis and its contribution to the assessment and treatment of patients living with mental health and substance use challenges. We outline how behavior analysts are trained and touch upon the practice of behavior analysis in North America and beyond. We describe collaborative relationships with other mental health professionals and, as an example, review the role of the behavior analyst on interprofessional teams in our mental health and addiction teaching hospital in Canada. We highlight some of the challenges faced by behavior analysts working in the mental health field and offer suggestions to increase their profile and opportunities for collaboration in clinical programs.

Supporting Children With Neurodevelopmental Disorders During the COVID-19 Pandemic

Families of children with neurodevelopmental disorders are especially vulnerable during the COVID-19 pandemic. Physical distancing requirements and closure of schools and services in the context of the COVID-19 pandemic are likely challenging to everyone but may be particularly impactful for families with children with neurodevelopmental disorders ([NDDs], eg, intellectual disability, attention-deficit/hyperactivity disorder [ADHD], autism spectrum disorder [ASD]). Although a small number of children may experience less stress or anxiety due to reduced social and academic expectations,¹ for many children with NDDs, and particularly those with ASD, carefully developed behavioral and environmental supports, and consistent and predictable routines and expectations, are vital for their mental well-being.² Consequently, abrupt discontinuation of these supports during quarantine and prolonged isolation creates a real risk for behavioral exacerbations in this vulnerable population.^3-6 Possible consequences for family members include physical and mental strain,⁷ whereas for the child with an NDD, increased emotional distress and challenging behavior may create safety concerns and the need for hospitalization.^4,6 Children with NDDs may be at increased risk for COVID and COVID-related complications,⁸ emphasizing the need for preventive and/or crisis behavioral health care availability outside of emergency and hospital settings.

Cost-Effectiveness Analysis of Stereotactic Ablative Body Radiation Therapy Compared With Surgery and Radiofrequency Ablation in Two Patient Cohorts: Metastatic Liver Cancer and Hepatocellular Carcinoma

AIMS

To compare the cost-effectiveness of stereotactic ablative body radiation therapy (SABR) with radiofrequency ablation and surgery in adult patients with metastatic liver cancer and hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Two patient cohorts were assessed: liver oligometastases and HCC. For each patient cohort, a decision analytic model was constructed to assess the cost-effectiveness of interventions over a 5-year horizon. A Markov process was embedded in the decision model to simulate the possible prognosis of cancer. Data on transition probabilities, survival, side-effects, quality of life and costs were obtained from published sources and the SABR Commissioning through Evaluation (CtE) scheme. The primary outcome was the incremental cost-effectiveness ratio with respect to quality-adjusted life-years. The robustness of the results was examined in a sensitivity analysis. Analyses were conducted from a National Health Service and Personal Social Services perspective.

RESULTS

In the base case analysis, which assumed that all three interventions were associated with the same cancer progression rates and mortality rates, SABR was the most cost-effective intervention for both patient cohorts. This conclusion was sensitive to the cancer progression rate, mortality rate and cost of interventions. Assuming a willingness-to-pay threshold of £20 000 per quality-adjusted life-year, the probability that SABR is cost-effective was 57% and 50% in liver oligometastases and HCC, respectively.

CONCLUSIONS

Our results indicate a potential for SABR to be cost-effective for patients with liver oligometastases and HCC. This finding supports further investigation in clinical trials directly comparing SABR with surgery and radiofrequency ablation.

A novel intronic variant in UBE3A identified by genome sequencing in a patient with an atypical presentation of Angelman syndrome

Angelman syndrome (AS) is a genetic neurodevelopmental disorder caused by loss or deficient expression of UBE3A on the maternally inherited allele. In 10-15% of individuals with a clinical diagnosis of AS, a molecular diagnosis cannot be established with conventional testing. We describe a 13-year-old male with an atypical presentation of AS, who was found to have a novel, maternally inherited, intronic variant in UBE3A (c.3-12T>A) using genome sequencing (GS). Targeted sequencing of RNA isolated from blood confirmed the creation of a new acceptor splice site. These GS results ended a six-year diagnostic odyssey and revealed a 50% recurrence risk for the unaffected parents. This case illustrates a previously unreported splicing variant causing AS. Intronic variants identifiable by GS may account for a proportion of individuals who are suspected of having well-known genetic disorders despite negative prior genetic testing.

Using Behavioral Approaches to Assess Memory, Imitation and Motor Performance in Children with Angelman Syndrome: Results of a Pilot Study

Purpose: This study was designed to assess memory, imitation of motor actions and motor performance by 12 children (age range 40-151 months) with Angelman syndrome (AS), a rare neurogenetic disorder associated with learning and memory impairments. Methods: Children's functioning was assessed at several time points over a 3-month period. Results: Memory and motor performance tests had acceptable test-retest and inter-rater reliability whereas the motor imitation test did not. Children were able to recall action sequences after a 24-h delay. Memory and motor performance scores were correlated with children's chronological age and raw scores on subdomains of the Vineland-II. Conclusions: These behavioral tests require further development and evaluation but may show promise to accompany standardized assessments that are currently in use with children with AS.

Benzodiazepine prescribing in a psychiatric hospital

Using a case note study, this paper presents a longitudinal survey of the effect of psychiatric inpatient care on benzodiazepine prescribing. Standards were proposed to assess the quality of this prescribing. Based on these standards, the study shows inappropriate use of benzodiazepines. Following admission, there was an increase in the number of patients prescribed benzodiazepines and in the number of benzodiazepines prescribed. Of the benzodiazepines withdrawn, most were contrary to the proposed standard. The quality of drug history showed little emphasis being placed on rationalising benzodiazepine prescribing. The issue of how benzodiazepines should be handled during psychiatric admission is discussed.

The prevalence and fate of the defunctioning stoma in patients with anal cancer: a regional experience following the ACT II trial

AIM

UK guidance advises the creation of a defunctioning stoma for anal tumours infiltrating the vagina, impending obstruction or significant faecal incontinence. Other patients may be offered a defunctioning stoma at the discretion of the clinician. The purpose of this study was to establish the prevalence and fate of defunctioning stomas in a regional anal cancer service, with reference to the results from the recent ACT II trial.

METHOD

Oncological treatment was standardized as described in the ACT II trial. All patients from 2010 to 2013 inclusive were included. Collected data were correlated with both the IMRT guidelines and the outcomes of the ACT II trial. Kaplan-Meier survival analysis was applied to stoma-free survival to the end of the study period.

RESULTS

Seventy-six patients were identified during the study period, of whom 51% had a defunctioning stoma. Twenty were performed for anterior tumours without infiltration into the vagina (Group A), whilst 19 had a stoma for indications as set out by the guidelines (Group B). Stoma reversal was performed in 41% of patients, 13/20 in Group A and 3/19 in Group B. The median time to reversal was 11 months. Eleven deaths were recorded and six patients still had their stomas at time of death. Stoma-free survival was 74%. No new ano-vaginal fistulation occurred as a consequence of treatment.

CONCLUSION

The tumour features that are indications for defunctioning as advised by the UK IMRT guidelines are associated with a poorer overall outcome, and these stomas are less likely to be reversed. The majority of stomas, however, were formed for anterior tumours without infiltration into the vagina and were more likely to be successfully reversed.

Self-Injury in Autism Spectrum Disorder and Intellectual Disability: Exploring the Role of Reactivity to Pain and Sensory Input

This paper provides information about the prevalence and topography of self-injurious behavior in children and adults with autism spectrum disorder and intellectual disability. Dominant models regarding the etiology of self-injury in this population are reviewed, with a focus on the role of reactivity to pain and sensory input. Neuroimaging studies are presented and suggestions are offered for future research.

Extended C-band tunable multi-channel InP-based coherent receiver PICs

Fully integrated monolithic, multi-channel InP-based coherent receiver PICs and transceiver modules with extended C-band tunability are described. These PICs operate at 33 and 44 Gbaud per channel under dual polarization (DP) 16-QAM modulation. Fourteen-channel monolithic InP receiver PICs show integration and data rate scaling capability to operate at 44 Gbaud under DP 16-QAM modulation for combined 4.9 Tb/s total capacity. Six channel simultaneous operation of a commercial transceiver module at 33 Gbaud is demonstrated for a variety of modulation formats including DP 16-QAM for >1.2Tbit/s aggregate data capacity.

Characterisation of antimicrobial usage in cats and dogs attending UK primary care companion animal veterinary practices

There is scant evidence describing antimicrobial (AM) usage in companion animal primary care veterinary practices in the UK. The use of AMs in dogs and cats was quantified using data extracted from 374 veterinary practices participating in VetCompass. The frequency and quantity of systemic antibiotic usage was described.Overall, 25 per cent of 963,463 dogs and 21 per cent of 594,812 cats seen at veterinary practices received at least one AM over a two-year period (2012-2014) and 42 per cent of these animals were given repeated AMs. The main agents used were aminopenicillin types and cephalosporins. Of the AM events, 60 per cent in dogs and 81 per cent in cats were AMs classified as critically important (CIAs) to human health by the World Health Organisation. CIAs of highest importance (fluoroquinolones, macrolides, third-generation cephalosporins) accounted for just over 6 per cent and 34 per cent of AMs in dogs and cats, respectively. The total quantity of AMs used within the study population was estimated to be 1473 kg for dogs and 58 kg for cats.This study has identified a high frequency of AM usage in companion animal practice and for certain agents classified as of critical importance in human medicine. The study highlights the usefulness of veterinary practice electronic health records for studying AM usage.

Neurodevelopmental outcomes in children with Angelman syndrome after 1 year of behavioural intervention

OBJECTIVE

To examine the impact of teaching approaches based on the principles of applied behaviour analysis (ABA) on neurodevelopmental outcomes in children with Angelman syndrome (AS).

METHODS

A non-randomized pre-test-post-test control group design was used. The intervention group consisted of four children with AS aged 3.1-9.2 years. Controls were other children with AS who were individually matched on the basis of chronological age, gender and molecular sub-type. Children in the intervention group were provided two-to-three ABA-based therapy sessions per week over a 1-year period. Standardized measures of cognitive, adaptive and language functioning were administered at baseline and after 1 year.

RESULTS

There were no statistically significant differences between the two groups at baseline or after 1 year. However, positive trends were observed in the intervention group for some cognitive and adaptive measures.

CONCLUSION

ABA-based intervention improved aspects of neurodevelopment for some children with AS and warrants further study.

Two-year prospective study of major depressive disorder in HIV-infected men

OBJECTIVE

The risks and factors contributing to major depressive episodes in HIV infection remain unclear. This 2-year prospective study compared cumulative rates and predictors of a major depressive episode in HIV-infected (HIV+) men (N=297) and uninfected (HIV-) risk-group controls (N=90).

METHODS

By design participants at entry were without current major depression, substance dependence or major anxiety disorder. Standardized neuromedical, neuropsychological, neuroimaging, life events, and psychiatric assessments (Structured Clinical Interview for DSM III-R) were conducted semi-annually for those with AIDS, and annually for all others.

RESULTS

Lifetime prevalence of major depression or other psychiatric disorder did not differ at baseline between HIV+ men and controls. On a two-year follow-up those with symptomatic HIV disease were significantly more likely to experience a major depressive episode than were asymptomatic HIV+ individuals and HIV-controls (p<0.05). Episodes were as likely to be first onset as recurrent depression. After baseline disease stage and medical variables associated with HIV infection were controlled, a lifetime history of major depression, or of lifetime psychiatric comorbidity (two or more psychiatric disorders), predicted subsequent major depressive episode (p<0.05). Neither HIV disease progression during follow-up, nor the baseline presence of neurocognitive impairment, clinical brain imaging abnormality, or marked life adversity predicted a later major depressive episode.

LIMITATIONS

Research cohort of men examined before era of widespread use of advanced anti-HIV therapies.

CONCLUSIONS

Symptomatic HIV disease, but not HIV infection itself, increases intermediate-term risk of major depression. Prior psychiatric history most strongly predicted future vulnerability.

Accuracy of frozen section diagnosis at surgery in pre- malignant and malignant lesions of the endometrium

OBJECTIVE

The purpose of this study was to correlate the histological diagnosis made during intraoperative frozen section examination of hysterectomies with atypical hyperplasia or carcinoma, with the definitive paraffin section histology.

STUDY DESIGN

Frozen section pathology results of patients with a preoperative biopsy showing atypical hyperplasia or endometrial carcinoma (87 patients) were compared retrospectively with paraffin section pathology findings. Those patients with curettage specimens showing atypical hyperplasia or curettings suspicious of endometrioid carcinoma had intraoperative frozen section to determine whether an invasive lesion was present and whether they required pelvic lymphadenectomy. The purpose of frozen section assessment in those patients who had a preoperative curettage specimen showing endometrial carcinoma was to identify poor prognostic pathological factors related to histological subtype, grade, depth of myometrial invasion and cervical involvement.

RESULTS

The correlation between frozen sections and paraffin histology in patients with endometrial carcinoma was 98.6% (69/70) for histological sub-type and 84.3% (59/70) for grade of differentiation. Depth of myometrial invasion was accurately diagnosed in 94.3% (66/70) while cervical involvement was accurately assessed in 86.7% (52/60). Of the 37 patients with atypical hyperplasia or suspicious curettings on preoperative curettage who had intraoperative frozen section, 23 patients had invasive malignancy, which was confirmed in subsequent paraffin sections. Of the remaining 14 patients with a non-malignant frozen section diagnosis, 11 were confirmed with paraffin sections while three had a small well differentiated invasive lesion, two were FIGO Stage 1a and one had microscopic invasion into the myometrium.

CONCLUSION

Intraoperative frozen section is a useful procedure to identify poor prognostic pathological factors as well as to diagnose endometrial cancer in patients undergoing hysterectomy for a preoperative biopsy diagnosis of atypical hyperplasia.

Stochastic vs. deterministic modeling of intracellular viral kinetics

Within its host cell, a complex coupling of transcription, translation, genome replication, assembly, and virus release processes determines the growth rate of a virus. Mathematical models that account for these processes can provide insights into the understanding as to how the overall growth cycle depends on its constituent reactions. Deterministic models based on ordinary differential equations can capture essential relationships among virus constituents. However, an infection may be initiated by a single virus particle that delivers its genome, a single molecule of DNA or RNA, to its host cell. Under such conditions, a stochastic model that allows for inherent fluctuations in the levels of viral constituents may yield qualitatively different behavior. To compare modeling approaches, we developed a simple model of the intracellular kinetics of a generic virus, which could be implemented deterministically or stochastically. The model accounted for reactions that synthesized and depleted viral nucleic acids and structural proteins. Linear stability analysis of the deterministic model showed the existence of two nodes, one stable and one unstable. Individual stochastic simulation runs could access and remain at the unstable node. In addition, deterministic and averaged stochastic simulations yielded different transient kinetics and different steady-state levels of viral components, particularly for low multiplicities of infection (MOI), where few virus particles initiate the infection. Furthermore, a bimodal population distribution of viral components was observed for low MOI stochastic simulations. The existence of a low-level infected subpopulation of cells, which could act as a viral reservoir, suggested a potential mechanism of viral persistence.

Frequency of spontaneous mutations in an avian hepadnavirus infection

In this study, we measured the frequency of revertants of a cytopathic strain of the duck hepatitis B virus that bears a single nucleotide substitution in the pre-S envelope protein open reading frame, resulting in the amino acid substitution G133E. Cytopathic virus mixed with known amounts of a genetically marked wild-type virus was injected into ducklings. Virus outgrowth was accompanied by a coselection of wild-type and spontaneous revertants during recovery of the ducklings from the acute liver injury caused by death of the G133E-infected cells. The frequency of individual revertants in the selected noncytopathic virus population was estimated by determining the ratio of each revertant to the wild-type virus. Spontaneous revertants were found to be present at frequencies of 1 x 10(-5) to 6 x 10(-5) per G133E genome inoculated. A mathematical model was used to estimate that the mutation rate was 0.8 x 10(-5) to 4.5 x 10(-5) per nucleotide per generation.

Urinary excretion profiles for total morphine, free morphine, and 6-acetylmorphine following smoked and intravenous heroin

Heroin is one of the major target drugs in workplace drug-testing programs because of its history of abuse, liability, and continued negative social impact. This study was a comprehensive examination of pharmacokinetics, pharmacodynamics, detection times, opiate immunoassay performance, and urine excretion profiles following single doses of heroin administered to human subjects via smoking and intravenous routes. Studies of the first four components of this investigation were previously published. This article describes the urine excretion profiles. Total morphine (Tmor), free morphine (Fmor), and 6-acetylmorphine (6-AM) were measured by gas chromatography-mass spectrometry (GC-MS) in 920 urine samples collected from 11 male human subjects following single doses of heroin. Eight received intravenous doses of 3, 6, and 12 mg heroin HCI and four smoked 3.5-, 5.2-, 7-, 10.5-, or 13.9-mg doses of heroin (base). In addition, 183 urine-based blind quality-control samples were added to the study set to assess assay performance. Creatinine was also measured in each sample by a colorimetric technique. The parameters studied were not significantly dependent on route of administration. Excretion half-life mean +/- SD for Tmor was 3.11 +/- 0.30 h. Range (median) of peak urine concentrations, time to peak, time to last positive sample for low cutoff (300 ng/mL) and high cutoff (2000 ng/mL) for Tmor following lower doses (< or = 7 mg) were, respectively, 1392-9250 (3620) ng/mL, 1.2-6.2 (2.3) h, 7.4-31.9 (7.4) h, and 0-10.1 (4.3) h. Following higher doses (> 10 mg) they were 2065-29,030 (16,470) ng/mL, 2.3-9.3 (4.5) h, 10.7-53.5 (34.4) h, 2.3-22.3 (8.3) h. Fmor peaked in the same sample as Tmor. Range (median) of peak Fmor concentrations and time to last positive using a cutoff of 100 ng/mL for low and high doses were, respectively, 117-1160 (415) ng/mL, 1.2-10.1 (4.5) h and 150-2580 (1400) ng/mL, 2.3-29.1 (9.3) h. The range (median) of peak urine concentrations for 6-AM was 6.1-568 (124) ng/mL. In general, the first urine void had the peak 6-AM concentration and was the only specimen positive at a 10-ng/mL cutoff. As previously reported urine concentrations varied greatly between subjects and within subjects with time after dosing but were much more predictable when values were reported as amount of drug per unit of creatinine. The range (median) values for percent of heroin excreted into urine as Tmor was 12.8-88.5% (51.0).

Managing impossible missions: ethical quandaries and ethical solutions

Healthcare financial managers are confronted daily with ethical and practical conflicts, particularly with regard to meeting the conflicting and unduly restrictive laws and regulations with which their organizations must comply. Sometimes the right course of action is not clear, as an examination of the 72-hour rule, safe harbor provisions, and legal interpretations of the False Claims Act reveals. Healthcare financial managers have an ethical duty, based on healthcare codes of ethics and ethical theories, to oppose laws and regulations that put their organizations in untenable legal and ethical situations.

Detection times and analytical performance of commercial urine opiate immunoassays following heroin administration

The Federal Workplace Drug Testing Program changed urine screening and confirmation cutoff concentrations for opiate testing from 300 to 2000 ng/mL in 1998. Morphine was the designated target compound. An additional heroin metabolite, 6-acetylmorphine (6-AM), was added to the testing procedure with a cutoff concentration > or = 10 ng/mL. Testing of 6-AM was required if morphine was positive to assist in medical review. A comparison of the new opiate cutoff concentrations was made with the older cutoff concentration at 300 ng/mL. Six commercial opiate immunoassays, four with a 300-ng/mL cutoff, ONLINE, EMIT, CEDIA and AxSym, and two with 2000-ng/mL cutoffs, ONLINE and EMIT, were selected to test 920 urine samples collected from 11 male human subjects following single doses of heroin. Eight received intravenous doses of 3, 6, and 12 mg heroin HCl and four smoked 3.5-, 5.2-, 10.5-, or 13.9-mg doses of heroin (base). In addition, 183 urine-based blind quality-control specimens were added to the study set to assess linearity, cross-reactivity, and interference. Total morphine, free morphine, and 6-AM were measured in each sample by gas chromatography-mass spectrometry (GC-MS). Linearity, cross-reactivity, and interference results for each immunoassay are described. Detection times, sensitivity, specificity, and efficiency of each assay were determined using data from the specimens collected after heroin administration. Detection times for morphine using the 300-ng/mL cutoff assays was approximately 12 h for low dose and 24 to 48 h for higher doses of heroin. For the two 2000-ng/mL cutoff concentration assays detection time was about 12 h. This was also the detection time for 6-AM by GC-MS. ONLINE had the lowest sensitivity, 60-74%, highest specificity, 98.8-100%, and least interference from a selection of common over-the-counter drugs and opioids. Increasing the cutoff to 2000 ng/mL from 300 ng/mL increased efficiencies of the assays from 72.7 to 82.6% to over 97%.

Low dynamic state of viral competition in a chronic avian hepadnavirus infection

The dynamic state of infection of 11 ducks with the duck hepatitis B virus was investigated. Chronic infections were established in newly hatched ducklings by inoculation with a mixture of wild-type virus and a mutant virus with a partial replication defect. As expected, the wild-type virus was rapidly enriched in the virus population during the spread of infection. Enrichment thereafter was correlated with normal growth of the liver, with the average mutant-to-wild-type ratio stabilizing for at least 2 months beyond the time at which the liver mass stabilized. Using experimentally determined growth rates for the mutant and wild-type viruses, we estimated that after the spread of infection, competition between the two virus strains was limited by the amount of replication required to infect new hepatocytes in the growing livers. The results suggest that, in a chronically infected liver, the selection of variants with a replication rate advantage is inefficient and that the emergence of such variants would depend on induced liver cell turnover, such as that occurring during chronic hepatitis.

The influence of HIV-related support groups on survival in women who lived with HIV. A pilot study

To determine the effect of support groups on survival, the authors retrospectively studied 21 HIV-seropositive women who died during the course of participation in a natural history study of HIV. Groups were composed of women who self-selected HIV support groups before death (n = 11) and a comparison group (n = 10). Survival analysis found group participation to be associated with increased longevity (73 months vs. 45 months; P = 0.011). Proportional-hazards regression demonstrated that HIV-related support groups and smaller family size significantly influenced survival (P = 0.0002). Factors related to group participation and ways in which support groups might promote longevity are discussed.

Experience of discordant beta hCG results by different assays in the management of non-seminomatous germ cell tumours of the testis

Fifty-five patients with non-seminomatous germ cell tumours (NSGCT) who were referred to a regional clinical oncology centre over a 3-year period were assessed prospectively with assays of the serum tumour markers alpha-feto protein (AFP) and beta-human chorionic gonadotropin (beta hCG). Paired baseline beta hCG assays were undertaken using a polyclonal radioimmunoassay (RIA) and a monoclonal fluoroimmunoassay (FIA). Serial paired measurements were undertaken in patients showing discordance on baseline assays. Four patients (7%; 95% confidence interval 0-14) showed discordance between the paired beta hCG assays. Of these, two showed elevated beta hCG on RIA, with normal levels on FIA; two showed elevated beta hCG on FIA, with normal levels on RIA. No discordance was noted with AFP assays. Discordance persisted in two of the patients (50%) and disappeared on treatment in one (25%); one patient died during treatment. Discordant beta hCG assays present difficulties in interpretation and have therapeutic implications in patients with NSGCT. No single currently available assay is conclusive in all patients and commercial assay kits should be chosen with care.