Nivolumab-Induced Lichen Planopilaris: Case Report and Literature Review of Hair Disorders Associated with Targeted Oncological Therapies

Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapies. Their mechanism promotes a cytotoxic T-cell activation against the tumor cells, but as a consequence, immune-mediated toxicities are increasingly being identified. Cutaneous immune-mediated adverse events (AE) occur in 32% of patients, with possible higher grade AEs seen with anti-programmed cell death protein 1, such as nivolumab. A 67-year-old woman with metastatic melanoma, previously treated for 2 years on dual ICI (ipilimumab and nivolumab), had her treatment interrupted due to grade-3 hepatitis. She was subsequently recommenced on single-agent nivolumab with good response, before discontinuation due to remission. She reported worsening scalp pruritus with associated erythema, scaling, and global hair thinning. On examination, she had significant erythema throughout the scalp with perifollicular scaling and evidence of scarring. She reported severe distress from her symptoms. Her scalp biopsy demonstrated features of scarring alopecia with infundibular and isthmic inflammation and interface change in keeping with lichen planopilaris. Follicular toxicities are rarely reported, possibly due to imprecise AE phenotyping or underreporting. However, growing evidence suggests that patients can develop follicular pigmentary changes and nonscarring alopecia. To our knowledge, this is the first case of scarring alopecia reported with nivolumab. Current treatments for ICI-induced toxicities are limited.

Lines under the eyes: a large prospective case series of linear basal cell carcinomas

Basal cell carcinomas (BCC) are the most common form of cancer globally. Linear BCCs are an unusual variant which are generally defined by having a length three times longer than the width and exhibiting relatively straight edges. In this report, we describe the largest global cohort (n = 31) with this rare subtype. Within this cohort, 22 were in the periocular region, 27 underwent Mohs micrographic surgery and 12 involved oculoplastic reconstruction. These results suggest that, whilst this subtype is relatively rare, it may be more prevalent than previously thought. Dermatologists and other specialities managing skin cancer, particularly ophthalmologists, should, therefore, be aware of this subtype, as it is often more aggressive than other BCC subtypes, often requiring multi-disciplinary management.

Global pattern in hunger and educational opportunity: a multilevel analysis of child hunger and TIMSS mathematics achievement

In low-income countries, there exists a common concern about the effect of hunger and food insecurity on educational outcomes. However, income inequalities, economic slowdown, conflict, and climate change have raised those concerns globally. Yet, little is known about how widespread the problem of hunger in schools is worldwide. This study examines child hunger and student achievement internationally, using data from the Trends in Mathematics and Science Study (TIMSS) 2019. To examine the relationship between hunger and student achievement, we fitted multilevel models to the data and controlled for student SES, class SES, teacher experience, and teacher educational attainment.  The results suggest that hunger among students is not exclusive to low-income countries. Instead, child hunger is a common issue around the world, affecting about one-third of children and exacerbating unequal education opportunities globally. Controlling for other variables, the achievement gap between students who never come to school hungry and those who come to school always or almost always hungry is significant and deserves our attention. A clear policy recommendation from our results suggests that all countries that participated in TIMSS need to examine their school meal programs and explore ways to feed the students who show up to school hungry.

Multistage Testing in Heterogeneous Populations: Some Design and Implementation Considerations

A central challenge in international large-scale assessments is adequately measuring dozens of highly heterogeneous populations, many of which are low performers. To that end, multistage adaptive testing offers one possibility for better assessing across the achievement continuum. This study examines the way that several multistage test design and implementation choices can impact measurement performance in this setting. To attend to gaps in the knowledge base, we extended previous research to include multiple, linked panels, more appropriate estimates of achievement, and multiple populations of varied proficiency. Including achievement distributions from varied populations and associated item parameters, we design and execute a simulation study that mimics an established international assessment. We compare several routing schemes and varied module lengths in terms of item and person parameter recovery. Our findings suggest that, particularly for low performing populations, multistage testing offers precision advantages. Further, findings indicate that equal module lengths-desirable for controlling position effects-and classical routing methods, which lower the technological burden of implementing such a design, produce good results. Finally, probabilistic misrouting offers advantages over merit routing for controlling bias in item and person parameters. Overall, multistage testing shows promise for extending the scope of international assessments. We discuss the importance of our findings for operational work in the international assessment domain.

Prevalence of wound complications following Mohs micrographic surgery: a cross-sectional study of 1000 patients undergoing Mohs surgery and wound repair in a UK teaching hospital

Background

Mohs micrographic surgery (MMS) for nonmelanoma skin cancer is often quoted as having an excellent safety profile.

Aim

To determine the complication rate of patients undergoing MMS in a large UK Mohs unit and subdivide complication rates into mild/intermediate and major, and to identify potential risk factors necessitating a clinical intervention.

Methods

This was a single‐centre, cross‐sectional study of 1000 consecutive cases of MMS performed with in‐house repair. Notes from the postsurgical dressing clinics were reviewed at Visit 1 (Days 7–14) and Visit 2 (approximately Week 6). Based upon the intervention required and effect on cosmetic/functional outcome, complications were classified as minor, intermediate or major. Logistic regression modelling was used to identify risk factors associated with a complication that needed a clinical intervention (i.e. intermediate or major).

Results

In total, 1000 Mohs surgeries were performed on 803 patients, resulting in 1067 excisions. Complication rates in our cohort were low (minor 3.6%, intermediate 3.1% and major 0.8%) Potential risk factors for developing a complication included skin graft (unadjusted OR = 4.89, 95% CI 1.93–12.39; fully adjusted OR = 7.13, 95% CI 2.26–22.45) and patients undergoing surgery on the forehead (unadjusted OR = 3.32, 95% CI 0.95–11.58; fully adjusted OR = 5.34, 95% CI 1.40–20.42). Patients whose wounds were allowed to heal by secondary intention healing (6.8%) exhibited no complications.

Conclusion

We advocate that patients should be informed during the consent procedure that less than 1 in every 100 patients (0.75%) undergoing MMS will have a serious adverse event (major complication) affecting their cosmetic or functional outcome.

Assessment of sex differences in ventricular-vascular coupling of left ventricular and aortic flow derived from 4D flow MRI in healthy, young adults

To gain further insight into male-female differences in cardiovascular conditions it is important to understand sex differences in healthy populations. A previous study from our group of 39 healthy young volunteers (20-35 years) paradoxically found that men had greater left ventricular (LV) kinetic energy (KE) but women had greater LV vorticity. We reanalyzed cardiac four-dimensional flow MRI data from 20 of the original subjects (10 male and 10 female) to quantify aortic flow in addition to LV flow. The combination of LV and aortic flow parameters were then used to calculate ventricular vascular coupling of KE and vorticity. The sex difference found in LV flow were not found in aortic flow and the ventricular-vascular coupling of LV-to-aortic flow was similar between men and women. Dimensional analysis to account for differences in cardiac output and ventricular volume explained the differences found in LV flow. The analysis methods and results of this study may be of further use in understanding ventricular vascular coupling of transported flow variables in healthy sex differences, healthy aging, and various cardiovascular conditions.

A pilot study of bladder voiding with real-time MRI and computational fluid dynamics

Lower urinary track symptoms (LUTS) affect many older adults. Multi-channel urodynamic studies provide information about bladder pressure and urinary flow but offer little insight into changes in bladder anatomy and detrusor muscle function. Here we present a novel method for real time MRI during bladder voiding. This was performed in a small cohort of healthy men and men with benign prostatic hyperplasia and lower urinary tract symptoms (BPH/LUTS) to demonstrate proof of principle; The MRI urodynamic protocol was successfully implemented, and bladder wall displacement and urine flow dynamics were calculated. Displacement analysis on healthy controls showed the greatest bladder wall displacement in the dome of the bladder while men with BPH/LUTS exhibited decreased and asymmetric bladder wall motion. Computational fluid dynamics of voiding showed men with BPH/LUTS had larger recirculation regions in the bladder. This study demonstrates the feasibility of performing MRI voiding studies and their potential to provide new insight into lower urinary tract function in health and disease.

In Vitro Assessment of Flow Variability in an Intracranial Aneurysm Model Using 4D Flow MRI and Tomographic PIV

Aneurysm rupture has been suggested to be related to aneurysm geometry, morphology, and complex flow activity; therefore, understanding aneurysm-specific hemodynamics is crucial. 4D Flow MRI has been shown to be a feasible tool for assessing hemodynamics in intracranial aneurysms with high spatial resolution. However, it requires averaging over multiple heartbeats and cannot account for cycle-to-cycle hemodynamics variations. This study aimed to assess cycle-to-cycle flow dynamics variations in a patient-specific intracranial aneurysm model using tomographic particle image velocimetry (tomo-PIV) at a high image rate under pulsatile flow conditions. Time-resolved and time-averaged velocity flow fields within the aneurysm sac and estimations of wall shear stress (WSS) were compared with those from 4D Flow MRI. A one-way ANOVA showed a significant difference between cardiac cycles (p value < 0.0001); however, differences were not significant after PIV temporal and spatial resolution was matched to that of MRI (p value 0.9727). This comparison showed the spatial resolution to be the main contributor to assess cycle-to-cycle variability. Furthermore, the comparison with 4D Flow MRI between velocity components, streamlines, and estimated WSS showed good qualitative and quantitative agreement. This study showed the feasibility of patient-specific in-vitro experiments using tomo-PIV to assess 4D Flow MRI with high repeatability in the measurements.

Intracranial vascular flow oscillations in Alzheimer's disease from 4D flow MRI

Recent modeling and experimental evidence suggests clearance of soluble metabolites from the brain can be driven by low frequency flow oscillations (LFOs) through the intramural periarterial drainage (IPAD) pathway. This study investigates the use of 4D flow MRI to derive LFOs from arterial and venous measures of blood flow. 3D radial 4D flow MRI data were acquired on a 3.0 T scanner and reconstructed using a low-rank constraint to produce time resolved measurements of blood flow. Physical phantom experiments were performed to validate the time resolved 4D flow against a standard 2D phase contrast (PC) approach. To evaluate the ability of 4D flow to distinguish physiologic flow changes from noise, healthy volunteers were scanned during a breath-hold (BH) maneuver and compared against 2D PC measures. Finally, flow measures were performed in intracranial arteries and veins of 112 participants including subjects diagnosed with Alzheimer's disease (AD) clinical syndrome (n = 23), and healthy controls (n = 89) on whom apolipoprotein ɛ4 positivity (APOE4+) and parental history of AD dementia (FH+) was known. To assess LFOs, flow range, standard deviation, demeaned temporal flow changes, and power spectral density were quantified from the time series. Group differences were assessed using ANOVA followed by Tukey-Kramer method for pairwise comparison for adjusted means (P < 0.05). Significantly lower LFOs as measured from flow variation range and standard deviations were observed in the arteries of AD subjects when compared to age-matched controls (P = 0.005, P = 0.011). Results suggest altered vascular function in AD subjects. 4D flow based spontaneous LFO measures might hold potential for longitudinal studies aimed at predicting cognitive trajectories in AD and study disease mechanisms.

Vascular Endothelial Growth Factor Blockade Induces Dermal Endothelial Cell Apoptosis in a Clinically Relevant Skin Organ Culture Model

BACKGROUND/AIMS

Vascular endothelial growth factor (VEGF), a key mediator of angiogenesis, plays a key role in physiological processes and is a major contributor to several diseases including cancer and psoriasis. Anti-VEGF therapies are widely used as cancer and ophthalmological treatments. There is some evidence that VEGF blockade may have utility in the management of psoriasis, although their potential has been largely unexplored. We hypothesized that a human skin organ culture could provide a stable ex vivo model in which the cutaneous microvascular network could be studied and experimentally manipulated.

METHODS

Punch biopsies (3 mm) of skin, donated by healthy individuals (39-72 years old, n = 5), were incubated with monoclonal antibody (mAb) to human VEGF (bevacizumab) at doses based on data from animal and clinical studies. After 3-day culture, cell death and proliferation as well as vascular endothelial cell changes were assessed using quantitative immunohistomorphometry.

RESULTS

Anti-VEGF mAb at 0.8 mg/mL induced a significant increase in cleaved caspase-3 expression in CD31+ cells (p < 0.05). None of the doses tested increased TUNEL or decreased Ki-67 expression in the basal layer of the epidermis, confirming the model's viability. In addition, the lactate dehydrogenase (LDH) assay showed no increase in LDH activity in treated samples compared to untreated control. The highest anti-VEGF mAb dose (0.8 mg/mL) induced an increase in TUNEL expression in the upper epidermis, which did not correlate with caspase-3 immunoreactivity. Further investigation revealed that anti-VEGF mAb did not change the expression of markers of terminal differentiation such as keratin 10, filaggrin, and involucrin, suggesting that VEGF depletion does not affect keratinocyte terminal differentiation. In contrast to the control group, levels of VEGF protein were undetectable in the culture supernatant of samples treated with 0.8 mg/mL of anti-VEGF mAb, suggesting sufficient dose.

CONCLUSION

Our pilot study provides the first evidence that anti-VEGF therapy promotes endothelial cell apoptosis in human skin ex vivo. Our pragmatic human skin organ culture assay offers a valuable tool for future preclinical endothelial cell and translational microvascular network/anti-angiogenesis research in human skin.

Prevalence of diabetes in Poland: a combined analysis of national databases

AIMS

To assess the number of people with diabetes in Poland using combined national sources and to evaluate the usefulness of data from an insurance system for epidemiological purposes.

METHODS

The data were collected from four sources: 1) 2013 all-billing records of the national insurance system comprising people of all age groups undergoing procedures or receiving services in primary healthcare, specialist practices and hospitals and also those receiving drugs; 2) an epidemiological study, NATPOL, that involved the assessment of people with undiagnosed diabetes; 3) the RECEPTOmetr Sequence study on prescriptions; and 4) regional child diabetes registries.

RESULTS

In 2013, 1.76 million people (0.98 million women and 0.79 million men) had medical consultations (coded E10-E14) and 2.13 million people (1.19 million women and 0.94 million men) purchased drugs or strip tests for diabetes. A total of 0.04 million people who used medical services did not buy drugs. In total, the number of people with diabetes in the insurance system was 2.16 million (1.21 million women and 0.95 million men), which corresponds to 6.1% (95% CI 6.11-6.14) of women and 5.1% (95% CI 5.12-5.14) of men. Including undiagnosed cases, the total number of people with diabetes in Poland was 2.68 million in 2013.

CONCLUSION

The estimated prevalence of diabetes (diagnosed and undiagnosed cases) in Poland is 6.97%. Data from the national insurance system with full coverage of the population can be treated as a reliable source of information on diseases with well-defined diagnosis and treatment methods, combined with an assessment of the number of undiagnosed individuals.

Modeling Physiological Flow Variation in Fontan Models with 4d Flow Mri, Particle Image Velocimetry, and Arterial Spin Labeling

The Fontan procedure is a successful palliation for single ventricle defect. Yet, a number of complications still occur in Fontan patients due to abnormal blood flow dynamics, necessitating improved flow analysis and treatment methods. Phase-contrast magnetic resonance imaging (MRI) has emerged as a suitable method for such flow analysis. However, limitations on altering physiological blood flow conditions in the patient while in the MRI bore inhibit experimental investigation of a variety of factors that contribute to impaired cardiovascular health in these patients. Furthermore, resolution and flow regime limitations in phase contrast MRI pose a challenge for accurate and consistent flow characterization. In this study, patient-specific physical models were created based on nine Fontan geometries and MRI experiments mimicking low and high flow conditions, as well as steady and pulsatile flow, were conducted. Additionally, an optically transparent Fontan model was created for flow analyses using a particle image velocimetry (PIV) system, arterial spin labeling (ASL), and four-dimensional (4D) flow MRI. Differences, though non-statistically significant, were observed between flow conditions and between patient-specific models. Large between-model variation supported the need for further improvement for patient-specific modeling on each unique Fontan anatomical configuration. Furthermore, high resolution PIV and flow tracking ASL data provided flow information that was not obtainable with 4D flow MRI alone.

First evidence of genotype-phenotype correlations in Gorlin syndrome

BACKGROUND

Gorlin syndrome (GS) is an autosomal dominant syndrome characterised by multiple basal cell carcinomas (BCCs) and an increased risk of jaw cysts and early childhood medulloblastoma. Heterozygous germline variants in PTCH1 and SUFU encoding components of the Sonic hedgehog pathway explain the majority of cases. Here, we aimed to delineate genotype-phenotype correlations in GS.

METHODS

We assessed genetic and phenotypic data for 182 individuals meeting the diagnostic criteria for GS (median age: 47.1; IQR: 31.1-61.1). A total of 126 patients had a heterozygous pathogenic variant, 9 had SUFU pathogenic variants and 46 had no identified mutation.

RESULTS

Patients with variants were more likely to be diagnosed earlier (p=0.02), have jaw cysts (p=0.002) and have bifid ribs (p=0.003) or any skeletal abnormality (p=0.003) than patients with no identified mutation. Patients with a missense variant in PTCH1 were diagnosed later (p=0.03) and were less likely to develop at least 10 BCCs and jaw cysts than those with other pathogenic PTCH1 variants (p=0.03). Patients with SUFU pathogenic variants were significantly more likely than those with PTCH1 pathogenic variants to develop a medulloblastoma (p=0.009), a meningioma (p=0.02) or an ovarian fibroma (p=0.015), but were less likely to develop a jaw cyst (p=0.0004).

CONCLUSION

We propose that the clinical heterogeneity of GS can in part be explained by the underlying or SUFU variant.

A qualitative study of the knowledge, behaviour and attitudes of patients with skin cancer regarding sunlight exposure and vitamin D

BACKGROUND

Solar UVR is a major cause of skin cancer but also an important source of vitamin D (VitD), essential for musculoskeletal health. Conflicting public health messages may confuse patients with skin cancer prone to further skin cancer.

OBJECTIVE

To explore the knowledge, behaviour and attitudes of patients with skin cancer to sunlight exposure and VitD sources.

METHODS

Patients (n = 10) previously treated for multiple basal cell cancer in a hospital setting participated in focus group sessions with semi-structured discussions to explore: knowledge of VitD, sun-avoidance behaviour and attitude towards sunlight exposure messages. Thematic data analysis was performed using software programme MAXQDA11.

RESULTS

Pre-existing knowledge of VitD was low. Most patients practised sun avoidance and were not inclined to increase exposure. Patients did not perceive VitD deficiency as a substantial risk to their own health, or a need to take VitD supplements. They aimed to increase VitD status through dietary intake, but knowledge of food VitD content was lacking.

CONCLUSIONS

The patients with skin cancer, appropriate to their heightened skin cancer risk, appeared unlikely to increase their sun exposure to gain VitD. However, education is required regarding the generally low levels of VitD in foodstuffs, and the requirement for supplements/fortified foods if strict sun avoidance is employed.

Implementing measurement-based care (iMBC) for depression in community mental health: a dynamic cluster randomized trial study protocol

Background

Measurement-based care is an evidence-based practice for depression that efficiently identifies treatment non-responders and those who might otherwise deteriorate [1]. However, measurement-based care is underutilized in community mental health with data suggesting fewer than 20 % of behavioral health providers using this practice to inform treatment. It remains unclear whether standardized or tailored approaches to implementation are needed to optimize measurement-based care fidelity and penetration. Moreover, there is some suggestion that prospectively tailored interventions that are designed to fit the dynamic context may optimize public health impact, though no randomized trials have yet tested this notion [2]. This study will address the following three aims: (1) To compare the effect of standardized versus tailored MBC implementation on clinician-level and client-level outcomes; (2) To identify contextual mediators of MBC fidelity; and (3) To explore the impact of MBC fidelity on client outcomes.

Methods/design

This study is a dynamic cluster randomized trial of standardized versus tailored measurement-based care implementation in Centerstone, the largest provider of community-based mental health services in the USA. This prospective, mixed methods implementation-effectiveness hybrid design allows for evaluation of the two conditions on both clinician-level (e.g., MBC fidelity) and client-level (depression symptom change) outcomes. Central to this investigation is the focus on identifying contextual factors (e.g., attitudes, resources, process, etc.) that mediate MBC fidelity and optimize client outcomes.

Discussion

This study will contribute generalizable and practical strategies for implementing systematic symptom monitoring to inform and enhance behavioral healthcare.

Trial registration

Clinicaltrials.gov NCT02266134.

Electronic supplementary material

The online version of this article (doi:10.1186/s13012-015-0313-2) contains supplementary material, which is available to authorized users.

An abnormality in glucocorticoid receptor expression differentiates steroid responders from nonresponders in keloid disease

Background

Glucocorticoids (GCs) are first‐line treatment for keloid disease (KD) but are limited by high incidence of resistance, recurrence and undesirable side‐effects. Identifying patient responsiveness early could guide therapy.

Methods

Nineteen patients with KD were recruited at week 0 (before treatment) and received intralesional steroids. At weeks 0, 2 and 4, noninvasive imaging and biopsies were performed. Responsiveness was determined by clinical response and a significant reduction in vascular perfusion following steroid treatment, using full‐field laser perfusion imaging (FLPI). Responsiveness was also evaluated using (i) spectrophotometric intracutaneous analysis to quantify changes in collagen and melanin and (ii) histology to identify changes in epidermal thickness and glycosaminoglycan (GAG) expression. Biopsies were used to quantify changes in glucocorticoid receptor (GR) expression using quantitative reverse transcriptase polymerase chain reaction, immunoblotting and immunohistochemistry.

Results

At week 2, the FLPI was used to separate patients into steroid responsive (n = 12) and nonresponsive groups (n = 7). All patients demonstrated a significant decrease in GAG at week 2 (P < 0·05). At week 4, responsive patients exhibited significant reduction in melanin, GAG, epidermal thickness (all P < 0·05) and a continued reduction in perfusion (P < 0·001) compared with nonresponders. Steroid‐responsive patients had increased GR expression at baseline and showed autoregulation of GR compared with nonresponders, who showed no change in GR transcription or protein.

Conclusions

This is the first demonstration that keloid response to steroids can be measured objectively using noninvasive imaging. FLPI is a potentially reliable tool to stratify KD responsiveness. Altered GR expression may be the mechanism gating therapeutic response.

What's already known about this topic?

Steroids are used as first‐line treatment for keloid disease, but response is variable with apparent steroid responders and nonresponders.

It remains unclear whether steroid responsiveness is due to an intrinsic difference in the mechanism of the glucocorticoid receptor (GR) action or reduced sensitivity to the steroid itself.

What does this study add?

We show for the first time the utility of noninvasive imaging techniques in stratifying steroid responsiveness in patients treated with steroids.

GR expression increased significantly in keloid tissue. Increased GR expression also correlated with an increased response to steroid treatment.

Steroid responders show a significant decrease in GR transcript and protein 2 weeks after steroid treatment (P < 0·05), which was not evident in steroid‐resistant patients.

A simple flashcard: big impact for junior doctors!

BACKGROUND

Reducing prescribing errors is key to ensuring patient safety. Foundation-year doctors (FYs) have been found to be major contributors to prescribing errors, and often feel poorly prepared for prescribing by their undergraduate education. Numerous studies have reported these findings; however, few studies have introduced meaningful interventions.

METHODS

A questionnaire was sent to FY2s (n = 20) to determine the 15 most commonly prescribed medications on call. These medications and instructions were incorporated into a flashcard that was disseminated to new FY1s at a teaching hospital in the UK. The FY1s were asked to complete a pre- and post-flashcard questionnaire, giving instructions for 10 medications and their confidence in prescribing these medications. A control group at another teaching hospital were given the same questionnaires, but not the flashcard.

RESULTS

No significant difference in confidence was seen in FY1s at either hospital before the flashcard was issued. Both groups at week 4 demonstrated significant improvements in confidence in prescribing, with those who received the flashcard demonstrating a significantly higher level of confidence in a greater range of medications, compared with those who did not (p < 0.05). At week 4, 93 per cent of FY1s still used the flashcard 2.2 times per day, claiming that it saved time on call (9.2/10).

DISCUSSION

We have introduced an inexpensive and simple prescribing aid, which has been statistically shown to improve prescribing confidence in FY1s. Foundation-year doctors have been found to be major contributors to prescribing errors.

Treatment of central venous catheter occlusions with ethanol and hydrochloric acid

BACKGROUND

Occluded central venous lines (CVLs) is a major problem in pediatric patients.

METHODS

To relieve obstructed catheters, infusions of ethanol (up to 3 mL of a 70% solution) for presumed lipid occlusions and hydrochloric acid (HCl, 0.1 N, up to 3 mL) for presumed mineral and drug precipitates were given in an attempt to relieve obstructed catheters.

RESULTS

Patency was restored in 34 of 39 occluded catheters over an 18-month period.

CONCLUSIONS

Clearing occluded CVLs with ethanol and HCl is not only beneficial to the patient but also offers considerable cost savings compared to CVL replacement.

Apoptosis among CD45RA-/low CD3+ progeny accompanies differentiation of human multinegative thymocytes

Apoptotic cell death is widely believed to be the fate of negatively selected cells in the thymus. In this work we have used multiparameter flow cytometry to analyse reductions in DNA content that occur among differentiating human CD3-4-8- multinegative (MN) thymocytes as they acquire CD3/TCR during in vitro culture. DNA content was measured as the intensity of the DNA-binding dye DAPI. The position of the diploid peak was identified by comparison to chicken red blood cells and to unfractionated uncultured thymocytes which have a sharply defined diploid peak. Apoptosis, was defined as a reduction in DNA content. Apoptotic cell death occurred continuously throughout the 7 day culture period and at the latest stages of culture DNA fragmentation was apparent on gels. Although both CD3- and CD3+ progeny became apoptotic, it was more frequent among the CD3+ progeny of the MN thymocytes. Apoptotic progeny included 60-70% CD3+ cells, while progeny remaining diploid were 8-36% CD3+. Fifty five per cent of CD3+ TCR delta 1+ progeny had less than 75% of the diploid DNA content, while for CD3+ TCR delta 1- progeny only 28% were in this category. CD3+ TCR delta 1+ progeny also comprised 66% of the cycling cells at days 6-7 of culture, suggesting a pattern of rapid cell division followed by apoptotic cell death for this subset. A lack of positive selection in culture may trigger apoptosis among the TCR delta 1 progeny. In contrast, TCR alpha beta progeny arising in culture appear to be less susceptible to apoptosis, perhaps due to their lack of CD4 and CD8. The expression of CD45RA and CD45R0 isoforms were assessed on the progeny of MN thymocytes based on their DNA content. Although 30% of apoptotic progeny expressed CD45RA, it was present at relatively low density compared to that on diploid or cycling cells, 55% of which were CD45RAhi. The majority of apoptotic cells expressed neither CD45RA or CD45R0, but were CD45+, indicating the presence of an isoform not detected by our monoclonal antibodies (MoAbs). This is consistent with speculations that apoptotic cell death among thymocytes is preceded by a transition in CD45 isoform expression. These conditions may model early selective events resulting from high avidity TCR engagement that is independent of CD4 and/or CD8.

Properties of amphiphilic and hydrophilic forms of alkaline phosphatase from human liver

Amphiphilic and hydrophilic forms of alkaline phosphatase differed in electrophoretic mobility, sensitivity to heat, activation by phospholipids and albumin, and affinity of monoclonal antibodies, but were similar in substrate Km and inhibitor Ki values, sensitivity to sodium dodecyl sulfate, and electrophoretic behavior on desialylation. Chemical cross-linking experiments failed to conclusively demonstrate an aggregated state of amphiphilic alkaline phosphatase in Triton X-100. Further, attempts to identify a polymeric hybrid between amphiphilic forms of human liver and placental alkaline phosphatase were unsuccessful. We conclude that the covalent attachment of the hydrophobic phosphatidyl-inositol membrane anchor causes the amphiphilic form to behave anomalously on electrophoresis and to affect certain of the enzyme's catalytic and physical properties.

Incorporation of human liver and placental alkaline phosphatases into liposomes and membranes is via phosphatidylinositol

As assessed by incorporation into liposomes and by adsorption to octyl-Sepharose, the integrity of the membrane anchor for the purified tetrameric forms of alkaline phosphatase from human liver and placenta was intact. Any treatment that resulted in a dimeric enzyme precluded incorporation and adsorption. An intact anchor also allowed incorporation into red cell ghosts. The addition of hydrophobic proteins inhibited incorporation into liposomes to varying degrees. Alkaline phosphatase was 100% releasable from liposomes and red cell ghosts by a phospholipase C specific for phosphatidylinositol. There was no appreciable difference in the rates of release of placental and liver alkaline phosphatases, although both were approximately 250 x slower in liposomes and 100 x slower in red cell ghosts than the enzyme's release from a suspension of cultured osteosarcoma cells. Both enzymes were released by phosphatidylinositol phospholipase C as dimers and would not reincorporate or adsorb to octyl-Sepharose. However, the enzyme incorporated, resolubilized by Triton X-100, and cleansed of the detergent by butanol treatment was tetrameric by gradient gel electrophoresis, was hydrophobic, and could reincorporate into fresh liposomes. A monoclonal antibody to liver alkaline phosphatase inhibited the enzyme's incorporation into liposomes, and abolished its release from liposomes and its conversion to dimers by phosphatidylinositol phospholipase C.

Effects of acid deposition on watershed ecosystems of national parks in the great lakes basin

Legally protected national parks provide an appropriate substrate for essential long-term study of ecosystem structure and function, and for detecting trends in natural and human-induced stress. The absence of unplanned site manipulation in such areas is especially valuable for such research. Our present research has two major components. The first is the long-term ecosystem-level study of the effects of atmospheric contaminants on ecosystem processes. The overall objective is to evaluate ecosystem aquatic/terrestrial linkages and their role in establishing aquatic ecosystem sensitivity to anthropic atmospheric inputs. Four watershed/lake ecosystems, representative of much of the region's diversity, are under study. Two mature boreal sites on Isle Royale are characterized by first-order perennial surface stream input and lake outflow. Two additional mainland northern hardwood sites, one with shallow soils and one with soils derived from glacial till, are characterized by sensitive aquatic systems. One site is in a private reserve and the other in Pictured Rocks National Lakeshore. Surface outflow is gaged by Parshall flume and stage height recorder. Meteorological stations record variables for estimating evapotranspiration. One-tenth ha plots have been established in all watersheds and three sites have had intensive study of precipitation modification by canopy and forest soil. Five-year mean maximum and minimum lake pH varies from 6.85 to 4.94, Ca(2+) from 1070 to 54 μ eq l(-1), K(+) from 5.42 to 8.35 μ eq l(-1), NH 4 (+) from 10.12 to 3.23 μ eq l(-1), HCO 3 (sup-) from 635 to 24 μ eq l(-1), NO 3 (sup-) from 3.27 to 1.54 μ eq l(-1), and SO 4 (sup2-) from 110 to 52.7 μ eq l(-1). The relatively high NO 3 (sup-) values observed in one lake are the result of stream drainage from a watershed dominated by Alnus rugosa, and another has high seasonal NO 3 (sup-) inputs during spring runoff. However, owing to periodic winter thaws, significant snowpack release of nutrients generally precedes maximum spring stream runoff. Water chemistry in both sensitive and non-sensitive lakes appears to be primarily reflecting how the conterminous terrestrial system is retaining atmospheric inputs more than the quality of direct lake atmospheric input. This is especially evident for H(+), NO 3 (sup-) and SO 4 (sup2-) .The second component is the assessment of watershed acidification, SO 4 (sup2-) output and soil retention across an input gradient. An anthropic deposition gradient provides the opportunity for intersite time-trend analyses as to the effects of inputs. Our study objective was to see if the decreasing west to east input/output values for SO 4 (sup2-) , noted in small first-order watersheds in national parks from Minnesota to Ohio, might be related to present atmospheric inputs, potential and total soil SO 4 (sup2-) adsorption, or soil SO 4 (sup2-) desorption from earlier higher inputs. Precipitation pH ranged from 5.05 at Fernberg, Minnesota to 4.24 at Wooster, Ohio. Minimum and maximum concentrations of NH 4 (+) , NO 3 (sup-) , SO 4 (sup2-) and Cl(-) were also found at these stations. Stream water concentrations of NO 3 (sup-) and SO 4 (sup2-) increase in a similar but sharper gradient. Streams are well buffered. Cation, HCO 3 (sup-) , NO 3 (sup-) and especially SO 4 (sup2-) output increase west to east, but H(+) output decreases. At the eastern site stream SO 4 (sup2-) concentration and output exceed HCO 3 (sup-) . Potential soil SO 4 (sup2-) adsorption capacity increases eastward, but this capacity is filled. Crystalline Fe hydrous oxides appear more effective than amorphous Fe hydrous oxides at adsorbing SO 4 (sup2-) . High anthropic anion inputs, inability of forest soil to adsorb additional inputs and perhaps SO 4 (sup2-) desorption appear responsible for the replacement of HCO 3 (sup-) by SO 4 (sup2-) in stream water. The major cation accompanying SO 4 (sup2-) is Ca(2+).

Influence of postvocalic consonants on vowel duration in esophageal speech

The durations of vowels preceding voiced-voiceless stops in utterances produced by three esophageal speakers and three normal speakers were measured. Vowels were significantly longer before voiced stops than before voiceless stops for both esophageal and normal speakers. For either postvocalic consonant environment, the average absolute durations of the vowels of the esophageal speakers were longer than those of the normal speakers. Speaker-group comparisons revealed no significant difference in vowel duration preceding voiceless stops; however, the average absolute duration of vowels preceding voiced stops was significantly longer for the esophageal group. Speaker-group comparisons revealed no significant differences in the relative differences in vowel duration preceding voiced-voiceless stops. The data were interpreted to support the view that the vowel length variation observed is a language-specific behavior governed by a phonological rule of the English language, rather than simply a language-universal behavior governed by inherent physiological characteristics of the speech-production mechanism. Moreover, it was suggested that this phonological rule is a lengthening rule, which lengthens vowels before voiced consonants, rather than a shortening rule, which shortens vowels before voiceless consonants.