The role of the district nurse in caring for patients with dementia.

District nurses require a vast array of skills to enable effective care delivery for patients living with a diagnosis of dementia in the community setting. Complex care needs provide challenges for the provision and delivery of district nursing services, which must be overcome to provide patientcentred care. Demographic and financial constraints hamper service delivery and the availability of services; however, district nurses are required to use their problem solving skills and tacit knowledge to deal with these challenges. The Northern Ireland Single Assessment Tool (NISAT) uses a person-centred framework to provide a holistic approach to care. The case study reflects a holistic and person centred approach to care for a person with dementia by a district nursing student.

The role of the district nurse in Northern Ireland.

A district nurse is an expert generalist practitioner who uses advanced clinical skills and knowledge to fulfil an ever-evolving role. The district nurse is accountable for the care planning, coordination and management of people with multi-faceted and intricate health care needs. In addition, an interprofessional approach to health and social care is required to enable the district nurse to co-ordinate care and enable patients to be cared for and remain within their homes. As the demand on primary and community services increases, care is further enriched by working in partnership with families, carers and voluntary service providers. The nurse patient relationship is the founding component for person-centred, holistic care. Through holistic assessment and shared decision making, co-produced care planning permits people to fundamentally take ownership of their health and enhances formal care provision. This case study reflects the role of the district nurse in Northern Ireland, through comprehensive assessment in clinical practice and highlights how a therapeutic relationship, being centred on the patient and shared decision-making impact positively on the care process.

Variation in small bowel length: factor in achieving total enteroscopy?

BACKGROUND AND AIM: Estimation of small bowel length is of interest following the recent development of device-assisted enteroscopy. This new technology allows access to the deep small bowel, but rates of examination of the entire small bowel (total enteroscopy) differ between study populations. Variation in small bowel length could factor into this observed irregularity in total enteroscopy rates. Medical literature contains limited information regarding small bowel length in living patients and conflicting data regarding small bowel length and its relationship to height and weight. We carried out small bowel measurements on surgical patients to further define the total length of the small bowel and its relationship to height, weight and body mass index (BMI). METHODS: Measurement of ileojejunal length on 91 surgical patients undergoing laparotomy for routine indications. Demographic data were collected for each subject, including height, weight and BMI. RESULTS: Small bowel length was found to vary widely between individuals (average 998.52 cm, range 630-1510 cm). Linear regression analysis demonstrated a statistically significant relationship between small bowel length and height (regression coefficient = 0.0561, P-value = 0.0238). A linear relationship between small bowel length and weight or BMI was not observed. CONCLUSIONS: Length of the small bowel in humans is pertinent to advances in deep enteroscopy and existing surgical applications such as intestinal bypass and prevention of short gut syndrome. If average small bowel length varies with height, total enteroscopy may be easier to achieve in patients who are short in stature.

Hepatitis E antibodies in laboratory rabbits from 2 US vendors.

We tested laboratory rabbits from 2 US vendors for antibodies against hepatitis E virus (HEV); Seroprevalences were 40% and 50%. Retrospective analysis of an ocular herpes simplex 1 experiment demonstrated that HEV seropositivity had no effect on experiment outcome. HEV probably is widespread in research rabbits, but effects on research remain unknown.

Enhancing person-centred care through the development of a therapeutic relationship.

More than ever, district nurses require highly developed communication and interpersonal skills to enable and nurture a therapeutic relationship. The 'shift left'-whereby patients are being assessed and cared for in the community at a much earlier stage of their illness or recovery-has significant implications. The complexity of patient care and the need for collaborative working and shared decision making necessitates a focus on fostering person-centred care and improving the patient experience in practice. District nurses are adept communicators with a specialist body of knowledge and skills. In Northern Ireland, the single assessment tool (NISAT) is used by health professionals and follows a person-centred framework. This case study reflects on the assessment process used by a district nursing student in clinical practice and demonstrates how a therapeutic relationship is developed, thereby supporting person centredness.

Prophylactic exchange-transfusion in sickle cell disease pregnancy: TAPS2 feasibility randomized controlled trial.

Serial prophylactic exchange blood transfusion (SPEBT) is increasingly used in pregnant women with sickle cell disease (SCD), despite a lack of robust evidence. TAPS2 (Transfusion Antenatally in Pregnant Women with Sickle Cell Disease) study assessed the feasibility and acceptability of conducting a definitive randomized controlled trial of SPEBT (intervention) versus standard care (control) in pregnant women with SCD. Women ≥18 years with SCD, between 6+0 and 18+0 weeks of singleton gestation, were randomized 1:1 to control or intervention every 6-10 weeks throughout pregnancy in seven hospitals in England. The main outcomes evaluated were recruitment rate (primary outcome), acceptability, and retention. Secondary outcomes were safety, maternal and infant clinical outcomes. 194 women were screened over 42 months (extended due to the pandemic), 88 were eligible, and 35 (39.8%) consented to participate. Eighteen participants were randomized to intervention and 17 to control. Follow-up data were collected on all participants. Twelve patients in the intervention group received at least one SPEBT, of these, 11 received  3. The remaining patient was withdrawn from SPEBT due to transfusion reaction. Sixteen control participants required at least one transfusion. There were no statistically significant differences in terms of maternal, infant, or postnatal outcomes. A trend towards a lower incidence of vaso-occlusive crisis, preterm delivery and improved birthweight was observed in the intervention group. Despite the pandemic, this study achieved satisfactory recruitment and retention, confirming its acceptability to participants. TAPS2 demonstrates that it is feasible to perform a definitive international trial of SPEBT in pregnant women with SCD. Trial registration: NIH registry (www.clinicaltrials.gov), registration number NCT03975894 (registered 05/06/19); ISRCTN (www.isrctn.com), registration number ISRCTN52684446 (retrospectively registered 02/08/19). TAPS2 trial Protocol: available at https://rdcu.be/drlwc.

Passive immunization with Pneumovax® 23 and pneumolysin in combination with vancomycin for pneumococcal endophthalmitis.

BACKGROUND: Capsule and pneumolysin (PLY) are two major virulence factors of Streptococcus pneumoniae. S. pneumoniae is one of the leading causes of bacterial endophthalmitis. The aim of this study is to determine whether passive immunization with the 23-valent pneumococcal polysaccharide vaccine (Pneumovax® 23; PPSV23) or PLY protects against pneumococcal endophthalmitis. METHODS: New Zealand white rabbits were passively immunized with antiserum to PLY, PPSV23, a mixture of PPSV23/PLY, or PBS (mock). Vitreous was infected with a clinical strain of S. pneumoniae. In a separate group of experiments, vancomycin was injected 4 hours post-infection (PI) for each passively immunized group. Severity of infection, bacterial recovery, myeloperoxidase (MPO) activity and percent loss of retinal function were determined. RESULTS: Passive immunization with each antiserum significantly lowered clinical severity compared to mock immunization (PPSV23 = 9.19, PPSV23/PLY = 10.45, PLY = 8.71, Mock = 16.83; P = 0.0467). A significantly higher bacterial load was recovered from the vitreous of PLY passively immunized rabbits 24 hours PI (7.87 log10 CFU) compared to controls (7.10 log10 CFU; P = 0.0134). Retinas from immunized rabbits were more intact. Vitreous of PLY (2.88 MPO untis/mL) and PPSV23/PLY (2.17) passively immunized rabbits had less MPO activity compared to controls (5.64; P = 0.0480), and both passive immunizations (PLY = 31.34% loss of retinal function, PPSV23/PLY = 27.44%) helped to significantly preserve retinal function compared to controls (64.58%; P = 0.0323). When vancomycin was administered 4 hours PI, all eyes were sterile at 24 hours PI. A significantly lower clinical severity was observed for rabbits administered the combination immunization (5.29) or PPSV23 (5.29) with vancomycin treatment compared to controls (17.68; P = 0.0469). CONCLUSIONS: Passive immunization with antisera to these antigens is effective in reducing clinical severity of pneumococcal endophthalmitis in rabbits. Addition of vancomycin to immunization is effective at eliminating the bacteria.

Serial prophylactic exchange blood transfusion in pregnant women with sickle cell disease (TAPS-2): statistical and qualitative analysis plan for a randomised controlled feasibility trial.

BACKGROUND: There are significant knowledge gaps regarding the effectiveness of serial prophylactic exchange blood transfusion (SPEBT) for pregnant women with sickle cell disease (SCD). The protocol for the randomised feasibility trial assessing SPEBT versus usual care in women with SCD (TAPS2 trial) has previously been published. This publication outlines the statistical and qualitative analysis plan for the study. METHODS AND DESIGN: TAPS2 is a randomised two-arm phase 2 feasibility trial with a nested qualitative study and health economic evaluation. Up to 50 pregnant women with SCD and a singleton pregnancy will be recruited and individually randomised to either SPEBT approximately every 6-10 weeks until delivery (intervention arm) or to usual care (control arm). Information will be collected on a range of feasibility and clinical outcomes. RESULTS: Due to the impact of COVID-19 on study recruitment, the initial study period of 24 months was extended to 48 months. Other protocol updates designed to mitigate the impact of COVID-19-related disruption included allowing for remote consent and conducting all qualitative interviews by telephone. The primary outcome for the trial is the overall recruitment rate. The number of women screened, eligible, consented, randomised and withdrawn will be summarised as a CONSORT flow diagram. Differences in clinical outcomes will additionally be presented as an initial assessment of efficacy and to inform sample size calculations for a future definitive trial. Qualitative interviews with trial participants and clinicians will be analysed using reflexive thematic analysis; data from interviews with participants who declined to participate in the trial will be extracted and incorporated into summary tables to report key findings. The health economic analysis plan is not covered by this update. CONCLUSION: The publication of this analysis plan is designed to aid transparency and to reduce the potential for reporting bias. TRIAL REGISTRATION: NIH registry ( www. CLINICALTRIALS: gov ), registration number NCT03975894 (registered 05/06/19); ISRCTN ( www.isrctn.com ), registration number ISRCTN52684446 (retrospectively registered 02/08/19).

HSV-1 latent rabbits shed viral DNA into their saliva.

BACKGROUND: Rabbits latent with HSV-1 strain McKrae spontaneously shed infectious virus and viral DNA into their tears and develop recurrent herpetic-specific corneal lesions. The rabbit eye model has been used for many years to assess acute ocular infections and pathogenesis, antiviral efficacy, as well as latency, reactivation, and recurrent eye diseases. This study used real-time PCR to quantify HSV-1 DNA in the saliva and tears of rabbits latent with HSV-1 McKrae. METHODS: New Zealand white rabbits used were latent with HSV-1 strain McKrae and had no ocular or oral pathology. Scarified corneas were topically inoculated with HSV-1. Eye swabs and saliva were taken from post inoculation (PI) days 28 through 49 (22 consecutive days). Saliva samples were taken four times each day from each rabbit and the DNA extracted was pooled for each rabbit for each day; one swab was taken daily from each eye and DNA extracted. Real-time PCR was done on the purified DNA samples for quantification of HSV-1 DNA copy numbers. Data are presented as copy numbers for each individual sample, plus all the copy numbers designated as positive, for comparison between left eye (OS), right eye (OD), and saliva. RESULTS: The saliva and tears were taken from 9 rabbits and from 18 eyes and all tested positive at least once. Saliva was positive for HSV-1 DNA at 43.4% (86/198) and tears were positive at 28.0% (111/396). The saliva positives had 48 episodes and the tears had 75 episodes. The mean copy numbers ± the SEM for HSV-1 DNA in saliva were 3773 ± 2019 and 2294 ± 869 for tears (no statistical difference). CONCLUSION: Rabbits latent with strain McKrae shed HSV-1 DNA into their saliva and tears. HSV-1 DNA shedding into the saliva was similar to humans. This is the first evidence that documents HSV-1 DNA in the saliva of latent rabbits.

Rabbit and mouse models of HSV-1 latency, reactivation, and recurrent eye diseases.

The exact mechanisms of HSV-1 establishment, maintenance, latency, reactivation, and also the courses of recurrent ocular infections remain a mystery. Comprehensive understanding of the HSV-1 disease process could lead to prevention of HSV-1 acute infection, reactivation, and more effective treatments of recurrent ocular disease. Animal models have been used for over sixty years to investigate our concepts and hypotheses of HSV-1 diseases. In this paper we present descriptions and examples of rabbit and mouse eye models of HSV-1 latency, reactivation, and recurrent diseases. We summarize studies in animal models of spontaneous and induced HSV-1 reactivation and recurrent disease. Numerous stimuli that induce reactivation in mice and rabbits are described, as well as factors that inhibit viral reactivation from latency. The key features, advantages, and disadvantages of the mouse and rabbit models in relation to the study of ocular HSV-1 are discussed. This paper is pertinent but not intended to be all inclusive. We will give examples of key papers that have reported novel discoveries related to the review topics.

Expression of vascular endothelial growth factor and pigment epithelial-derived factor in a rat model of retinopathy of prematurity.

OBJECTIVE: To determine the effects of oxygen fluctuations on pigment epithelial-derived factor (PEDF) and vascular endothelial growth factor (VEGF)/PEDF ratios in a relevant rat model of retinopathy of prematurity (ROP). METHODS: The expression of retinal PEDF mRNA and of VEGF and PEDF protein were determined using real-time polymerase chain reaction or enzyme-linked immunosorbent assays at different postnatal day ages for rat pups raised in room air (RA) or in a rat model mimicking ROP. Statistical outcomes were determined with factorial analyses of variance. Mean VEGF and PEDF protein levels were determined at different ages for rats in the ROP model and for RA-raised rats, and the ratio of VEGF/PEDF protein versus age was plotted. At postnatal day (P) 14, inner retinal plexus vascularization had extended to the ora serrata in pups raised in RA. In the ROP model, avascular retina persisted at P14 and intravitreous neovascularization developed at P18. Therefore, VEGF and PEDF expression was determined in the ROP model and in RA-raised rat pups at P14 and P18. RESULTS: Older age was associated with increased PEDF mRNA (p<0.001), PEDF protein (p=0.005), and VEGF protein (p=0.005), and VEGF protein (p<0.0001). Exposure to fluctuations of oxygen in the 50/10 oxygen-induced retinopathy model compared to RA was associated with increased PEDF mRNA (p=0.0185), PEDF protein (p<0.0001), or VEGF protein (p<0.0001). The VEGF/PEDF ratio favored angiogenic inhibition (<1.0) before but not on P14, when avascular retina persisted in the ROP model but not in RA. The VEGF/PEDF ratio favored angiogenesis (>1.0) at P14 and P 18 when intravitreous neovascularization occurred in the ROP model. CONCLUSIONS: Increased expression levels of VEGF and PEDF are associated with older postnatal day age or with exposure to fluctuations in oxygen in the 50/10 oxygen-induced retinopathy model compared to RA. PEDF protein more closely associates with avascular retinal features and neovascularization than does VEGF protein or the VEGF/PEDF in the ROP model. Although PEDF has been proposed as a potential treatment in ROP, interventional studies using PEDF in an ROP model to potentially reduce intravitreous neovascularization are required to determine timing, efficacy, and dose of PEDF.

The polycomb group protein Bmi1 binds to the herpes simplex virus 1 latent genome and maintains repressive histone marks during latency.

The mechanism by which herpes simplex virus 1 (HSV-1) establishes latency in sensory neurons is largely unknown. Recent studies indicate that epigenetic modifications of the chromatin associated with the latent genome may play a key role in the transcriptional control of lytic genes during latency. In this study, we found both constitutive and facultative types of heterochromatin to be present on the latent HSV-1 genome. Deposition of the facultative marks trimethyl H3K27 and histone variant macroH2A varied at different sites on the genome, whereas the constitutive marker trimethyl H3K9 did not. In addition, we show that in the absence of the latency-associated transcript (LAT), the latent genome shows a dramatic increase in trimethyl H3K27, suggesting that expression of the LAT during latency may act to promote an appropriate heterochromatic state that represses lytic genes but is still poised for reactivation. Due to the presence of the mark trimethyl H3K27, we examined whether Polycomb group proteins, which methylate H3K27, were present on the HSV-1 genome during latency. Our data indicate that Bmi1, a member of the Polycomb repressive complex 1 (PRC1) maintenance complex, associates with specific sites in the genome, with the highest level of enrichment at the LAT enhancer. To our knowledge, these are the first data demonstrating that a virus can repress its gene transcription to enter latency by exploiting the mechanism of Polycomb-mediated repression.

Serial prophylactic exchange blood transfusion in pregnant women with sickle cell disease (TAPS-2): study protocol for a randomised controlled feasibility trial.

BACKGROUND: Pregnancies in women with sickle cell disease (SCD) are associated with a higher risk of sickle and pregnancy complications. Limited options exist for treating SCD during pregnancy. Serial prophylactic exchange blood transfusion (SPEBT) has been shown to be effective in treating SCD outside pregnancy, but evidence is lacking regarding its use during pregnancy. The aim of this study is to assess the feasibility and acceptability of conducting a future phase 3 randomised controlled trial (RCT) to establish the clinical and cost effectiveness of SPEBT in pregnant women with SCD. METHODS: The study is an individually randomised, two-arm, feasibility trial with embedded qualitative and health economic studies. Fifty women, 18 years of age and older, with SCD and a singleton pregnancy at ≤ 18 weeks' gestation will be recruited from six hospitals in England. Randomisation will be conducted using a secure online database and minimised by centre, SCD genotype and maternal age. Women allocated to the intervention arm will receive SPEBT commencing at ≤ 18 weeks' gestation, performed using automated erythrocytapheresis every 6-10 weeks until the end of pregnancy, aiming to maintain HbS% or combined HbS/HbC% below 30%. Women in the standard care arm will only receive transfusion when clinically indicated. The primary outcome will be the recruitment rate. Additional endpoints include reasons for refusal to participate, attrition rate, protocol adherence, and maternal and neonatal outcomes. Women will be monitored throughout pregnancy to assess maternal, sickle, and foetal complications. Detailed information about adverse events (including hospital admission) and birth outcomes will be extracted from medical records and via interview at 6 weeks postpartum. An embedded qualitative study will consist of interviews with (a) 15-25 trial participants to assess experiences and acceptability, (b) 5-15 women who decline to participate to identify barriers to recruitment and (c) 15-20 clinical staff to explore fidelity and acceptability. A health economic study will inform a future cost effectiveness and cost-utility analysis. DISCUSSION: This feasibility study aims to rigorously evaluate SPEBT as a treatment for SCD in pregnancy and its impact on maternal and infant outcomes. TRIAL REGISTRATION: NIH registry (www.clinicaltrials.gov), registration number NCT03975894 (registered 05/06/19); ISRCTN (www.isrctn.com), registration number ISRCTN52684446 (retrospectively registered 02/08/19).

The high prevalence of herpes simplex virus type 1 DNA in human trigeminal ganglia is not a function of age or gender.

The purpose of this study was to determine the presence and copy numbers of herpes simplex virus type 1 (HSV-1) DNA in human trigeminal ganglia (TG) with respect to age, gender, and postmortem interval (PMI). Human TG (n = 174, obtained from the Oregon Brain Bank, with data on age, gender, and PMI) were analyzed for HSV-1 DNA copies (HSV-1 DNA polymerase gene) by using real-time PCR. We found that 89.1% (131/147) of subjects and 90.1% (155/174) of TG contained HSV-1 DNA. The copy numbers of HSV-1 DNA in the positives ranged from very high (>10(6)) to very low (5). These data confirm and strengthen our previous findings that subjects were positive for HSV-1 DNA in tears (46/50; 92%) and saliva (47/50; 94%). These TG data and tear and saliva data demonstrated considerable variability in copy numbers of HSV-1 DNA per subject. Statistical analysis showed no significant relationship between gender and copy number, age and copy number, or PMI and copy number for each pair of variables. A factorial analysis of gender, age, and PMI with respect to copy number also showed no statistical significance. This is the first study that provides statistical analysis that documents that the prevalence of HSV-1 DNA in the human TG is not a function of either gender or age.

The impact of stroke consequences on spousal relationships from the perspective of the person with stroke.

AIMS AND OBJECTIVES: This paper aims to provide a subjective insight into the experience of stroke recovery within spousal relationships. The aftermath of stroke and its impact on the physical, emotional, psychological and social effects of spousal relationships are explored. BACKGROUND: Many studies have examined observable functional recovery following stroke from the perspective of health care professionals. Longer-term effects of stroke such as changes in role and perception of self can alter significantly the dynamics of spousal relationships. Despite this, little attention has been given to the subjective impact of stroke on spousal relationships. DESIGN: A qualitative study design was adopted. Individual, audio-taped interviews were carried out over three months. METHODS: A convenience sample of 16 stroke survivors was recruited from the Stroke Nurse Specialist Register. All participants were over 18 years old and had been discharged from hospital following a diagnosis of stroke. Transcribed interviews were analysed using content data analysis to code and categorise emerging themes. RESULTS: Poststroke, spousal relationships altered significantly in terms of sexuality, sexual desire and sexual functioning. Within their role of husband or wife, stroke survivors described a lack of control and dramatic changes in their perception of self. CONCLUSIONS: Survivors of stroke experience profound, complex and multi-faceted difficulties in many areas of their spousal relationships, which are distressing to both them and their spouses. These have a significant impact on each individual's quality of life particularly in the longer term. RELEVANCE TO CLINICAL PRACTICE: Health care professionals and service providers need to understand and recognise the subjective experience of stroke and the complex difficulties that stroke survivors experience within their spousal relationships. It would appear that current service provision does not adequately address the range of needs that the stroke survivors described in this study.

Effect of human apolipoprotein E genotype on the pathogenesis of experimental ocular HSV-1.

The isoform-specific role of human apolipoprotein E (apoE) has been assessed in a mouse model of ocular herpes. Female, age-matched transgenic mice knocked-in for the human allele apoE3 or apoE4 and their parent C57Bl/6 mice were inoculated corneally with HSV-1 strain KOS. Ocular HSV-1 pathogenesis was monitored through viral replication and clinical progression of stromal opacity and neovascularization by slit-lamp examination. Establishment of latency was determined by analysis of HSV-1 DNA (copy number) by specific real-time PCR in the cornea, trigeminal ganglia (TG), and brain. Representative groups of transgenic mice were sacrificed for the analysis of gene expression of vascular endothelial growth factor (VEGF) by reverse-transcription PCR, and apoE expression by Western blot analysis. At 6days post-infection (P.I.), the ocular infectious HSV-1 titer was significantly higher (p<0.05) in apoE4 mice compared with apoE3 and C57Bl/6 mice. Corneal neovascularization in apoE4 mice was significantly higher (p<0.05) than apoE3 and C57Bl/6 mice. The onset of corneal opacity in apoE4 mice was accelerated during days 9-11 P.I.; however, no significant difference in severity was seen on P.I. days 15 and beyond. At 28 days P.I., infected mice of all genotypes had no significant differences in copy numbers (range 0-15) of HSV-1 DNA in their corneas, indicating that HSV-1 DNA copy numbers in cornea are independent of apoE isoform regulation. At 28 days P.I., both apoE4 and C57Bl/6 mice had a significantly higher (p=0.001) number of copies of HSV-1 DNA in TG compared with apoE3. ApoE4 mice also had significantly higher (p=0.001) copies of HSV-1 DNA in their TGs compared with C57Bl/6 mice. In brain, both apoE4 and C57Bl/6 mice had significantly higher numbers (p

Efficacy of a helicase-primase inhibitor in animal models of ocular herpes simplex virus type 1 infection.

PURPOSE: The aim of this study was to evaluate the effect of BAY 57-1293, a helicase-primase inhibitor, on herpes simplex virus type 1 (HSV-1) reactivation in mice and its efficacy on established disease in rabbits. METHODS: BALB/c mice latent for McKrae-strain HSV-1 were reactivated via heat stress, treated with BAY 57-1293, and their corneas were swabbed for virus or the trigeminal ganglia (TG) obtained for quantification of viral DNA. New Zealand white rabbits were infected and treated topically or orally in comparison with trifluridine or valacyclovir. RESULTS: Oral BAY 57-1293 suppressed reactivation in HSV-1-infected mice and reduced the viral load in TG up to four orders of magnitude. In the rabbits, the therapeutic efficacies of topical BAY 57-1293 and trifluridine were similar. Once-daily oral BAY 57-1293 was significantly more effective than valacyclovir and as effective as twice a day topical trifluridine. CONCLUSIONS: BAY 57-1293 may be more effective than valacyclovir, without the cytotoxicity or potential healing retardation seen with trifluridine. Oral BAY 57-1293 may be a substitute for eye drops as an effective treatment for herpetic keratitis and might be useful in treating stromal keratitis and iritis, as well as preventing recurrences of ocular herpes.

3-D histomorphometry of the normal and early glaucomatous monkey optic nerve head: prelaminar neural tissues and cupping.

PURPOSE: To introduce a three-dimensional (3-D) histomorphometric strategy for characterizing the connective tissue (laminar) and prelaminar neural tissue (prelaminar) components of optic nerve head (ONH) cupping in one bilaterally normal monkey and three monkeys with early experimental glaucoma (EG) in one eye. METHODS: Trephined ONH and peripapillary sclera from both eyes of four monkeys were serially sectioned at either 3-mum thickness (three EG monkeys) or 1.5-microm thickness (the bilaterally normal monkey) with the embedded tissue block face stained and imaged after each cut. Digital section images were aligned and stacked to create a 3-D reconstruction of each ONH. Within 40 digital radial sagittal sections of each reconstruction, Bruch's membrane opening (BMO), the neural canal wall, and the anterior laminar surface were delineated by two delineators. The 80 BMO points were used to establish a BMO-zero reference plane. The parameters prelaminar tissue volume, post-BMO cup (the estimate of the clinical cup), and post-BMO total prelaminar volume (a global measure of ONH connective tissue deformation) were calculated overall and within 15 degrees radial regions. The parameter prelaminar tissue thickness was calculated at each delineated anterior laminar surface point. For each monkey, an intra-animal difference map was generated for each parameter. Overall volume and thickness data were compared between normal and EG eyes by analysis of variance (ANOVA). RESULTS: Regionally variable expansion of post-BMO cup volume and post-BMO total prelaminar volume were present in all three EG eyes and far exceeded the intra-animal, physiologic differences for these parameters in the bilaterally normal monkey. Prelaminar tissue thickness was increased in all three EG monkeys, with the greatest effects present within the peripheral regions of the canal. CONCLUSIONS: These data suggest that in young adult monkeys with more compliant connective tissues, clinical cupping in early glaucoma is primarily due to fixed deformation of the ONH connective tissues and occurs in the setting of prelaminar tissues that are thickened rather than thinned.

Three-dimensional histomorphometry of the normal and early glaucomatous monkey optic nerve head: neural canal and subarachnoid space architecture.

PURPOSE: To delineate three dimensionally the neural canal landmarks-Bruch's membrane opening (BMO), anterior sclera canal opening (ASCO), anterior laminar insertion (ALI), posterior laminar insertion (PLI), and posterior scleral canal opening (PSCO)-and the anterior-most aspect of the subarachnoid space (ASAS), within digital three-dimensional (3-D) reconstructions of the monkey optic nerve head (ONH). METHODS: The trephinated ONH and peripapillary sclera from both eyes of three early glaucoma (EG) monkeys (one eye normal, one eye with laser-induced EG) were serial sectioned at 3-microm thickness, with the embedded tissue block face stained and imaged after each cut. The images were aligned and stacked in a 3-D volume, within which the BMO, ASCO, ALI, PLI, PSCO, and ASAS were delineated in 40 digital, radial, and sagittal sections. An ellipse was fitted to the 80 BMO points to establish a BMO zero reference plane, on which all other points were projected. The distance from each projected point to the BMO centroid (offset) and BMO zero reference plane (depth) were calculated and compared regionally between normal and EG eyes, both overall and within each monkey, by analysis of variance. RESULTS: BMO was the clinically visible optic disc margin in all six eyes. The neural canal architecture was highly variable in the three normal eyes. Radial expansion of the neural canal was greatest posteriorly in the EG eyes. Axial elongation of the canal was less pronounced overall but was regionally present within all three EG eyes. ASAS was regionally radially expanded and anteriorly displaced within two of the three EG eyes. CONCLUSIONS: Profound deformation of the neural canal and ASAS architecture are present in young adult monkey eyes at the onset of ONH surface change in early experimental glaucoma.

3-D histomorphometry of the normal and early glaucomatous monkey optic nerve head: lamina cribrosa and peripapillary scleral position and thickness.

PURPOSE: To delineate three-dimensionally the anterior and posterior surfaces of the lamina cribrosa, scleral flange, and peripapillary sclera, to determine the position and thickness of these structures within digital three-dimensional (3-D) reconstructions of the monkey optic nerve head (ONH). METHODS: The trephinated ONH and peripapillary sclera from both eyes of three monkeys with early glaucoma (EG; one eye normal, one eye given laser-induced EG) were serially sectioned at 3-mum thickness, with the embedded tissue block's face stained and imaged after each cut. Images were aligned and stacked to create 3-D reconstructions, within which Bruch's membrane opening (BMO) and the anterior and posterior surfaces of the lamina cribrosa and peripapillary sclera were delineated in 40 serial radial (4.5 degrees interval) digital sagittal sections. For each eye, a BMO zero reference plane was fit to the 80 BMO points, which served as the reference from which all position measurements were made. Regional laminar, scleral flange, and peripapillary scleral position and thickness were compared between the normal and EG eyes of each monkey and between treatment groups by analysis of variance. RESULTS: Laminar thickness varied substantially within the normal eyes and was profoundly thicker within the three EG eyes. Laminar position was permanently posteriorly deformed in all three EG eyes, with substantial differences in the magnitude and extent of deformation among them. Scleral flange and peripapillary scleral thickness varied regionally within each normal ONH with the scleral flange and peripapillary sclera being thinnest nasally. Overall, the scleral flange and peripapillary sclera immediately surrounding the ONH were posteriorly displaced relative to the more peripheral sclera. CONCLUSIONS: Profound fixed posterior deformation and thickening of the lamina are accompanied by mild posterior deformation and thinning of the scleral flange and peripapillary sclera at the onset of confocal scanning laser tomography (CSLT)-detected ONH surface change in young adult monkey eyes with early experimental glaucoma.