Association of Contrast Sensitivity With Eye Disease and Vision-Related Quality of Life

PURPOSE

To investigate contrast sensitivity (CS) as a screening tool to detect eye disease and assess its association with both eye disease and vision-related quality of life.

DESIGN

Cross-sectional study.

METHODS

Setting and population: Adults receiving care from a free clinic and a Federally Qualified Health Center in Michigan.

MAIN OUTCOME MEASURES

Screening positive for eye disease and Visual Function Questionnaire (VFQ) score.

OBSERVATION

Participants received a vision exam reviewed via telemedicine for disease, completed a demographic survey, and the 9-item VFQ. The ability of CS to predict eye disease was explored and area under the curve (AUC) is reported. Logistic and linear regression were used to investigate the continuous effect of CS on the probability of screening positive for eye disease and VFQ score, respectively, adjusting for age and visual acuity.

RESULTS

1159 included participants were, on average, 54.9 ± 14.5 years old, 62% identified as female, 34% as White, 54% as Black, 10% as Hispanic/Latino, and reported mean VFQ score of 79.7 ± 15.3. CS ranged from 0.00 to 1.95 log units (mean = 1.54 ± 0.24), 21% of eyes had glaucoma, 19% cataract, 6% DR, and 2% AMD. AUCs were 0.53 to 0.73. A 0.3 log unit decrease in better eye CS was associated with increased odds of glaucoma (odds ratio [OR] = 1.35, confidence interval [CI] = 1.09-1.67), cataract (OR = 1.35, CI = 1.05-1.72), DR (OR = 2.05, CI = 1.51-2.77), and AMD (OR = 2.08, CI = 1.10-3.91). A 0.3 log unit increase in better eye CS was associated with a 5.9 unit increase in VFQ.

CONCLUSION

While CS alone is not sufficient to identify people with eye disease, it is an important measure of visual function that can add value to comprehensive eye screening.

A practical evidence-based approach to management of type 2 diabetes in children and young people (CYP): UK consensus

BACKGROUND

Type 2 diabetes in young people is an aggressive disease with a greater risk of complications leading to increased morbidity and mortality during the most productive years of life. Prevalence in the UK and globally is rising yet experience in managing this condition is limited. There are no consensus guidelines in the UK for the assessment and management of paediatric type 2 diabetes.

METHODS

Multidisciplinary professionals from The Association of Children's Diabetes Clinicians (ACDC) and the National Type 2 Diabetes Working Group reviewed the evidence base and made recommendations using the Grading Of Recommendations, Assessment, Development and Evaluation (GRADE) methodology.

RESULTS AND DISCUSSION

Young people with type 2 diabetes should be managed within a paediatric diabetes team with close working with adult diabetes specialists, primary care and other paediatric specialties. Diagnosis of diabetes type can be challenging with many overlapping features. Diabetes antibodies may be needed to aid diagnosis. Co-morbidities and complications are frequently present at diagnosis and should be managed holistically. Lifestyle change and metformin are the mainstay of early treatment, with some needing additional basal insulin. GLP1 agonists should be used as second-line agents once early ketosis and symptoms are controlled. Glycaemic control improves microvascular but not cardiovascular risk. Reduction in excess adiposity, smoking prevention, increased physical activity and reduction of hypertension and dyslipidaemia are essential to reduce major adverse cardiovascular events.

CONCLUSIONS

This evidence-based guideline aims to provide a practical approach in managing this condition in the UK.

Visual Impairment from Uncorrected Refractive Error among Participants in a Novel Program to Improve Eye Care Access among Low-Income Adults in Michigan

PURPOSE

To assess the rate of visual impairment (VI) from uncorrected refractive error (URE) and associations with demographic and socioeconomic factors among low-income patients presenting to the Michigan Screening and Intervention for Glaucoma and Eye Health through Telemedicine (MI-SIGHT) program.

DESIGN

Cross-sectional study.

PARTICIPANTS

Adults ≥ 18 years without acute ocular symptoms.

METHODS

MI-SIGHT program participants received a telemedicine-based eye disease screening and ordered glasses through an online optical store. Participants were categorized based on refractive error (RE) status: VI from URE (presenting visual acuity [PVA], ≤ 20/50; best-corrected visual acuity [BCVA], ≥ 20/40), URE without VI (PVA, ≥ 20/40; ≥ 2-line improvement to BCVA), and no or adequately corrected RE (PVA, ≥ 20/40; < 2-line improvement to BCVA). Patient demographics, self-reported visual function, and satisfaction with glasses obtained through the program were compared among groups using analysis of variance, Kruskal-Wallis, chi-square, and Fisher exact testing.

MAIN OUTCOME MEASURES

PVA, BCVA, and presence of VI (defined as PVA ≤ 20/50).

RESULTS

Of 1171 participants enrolled in the MI-SIGHT program during the first year, average age was 55.1 years (SD = 14.5), 37.7% were male, 54.1% identified as Black, and 1166 (99.6%) had both PVA and BCVA measured. VI was observed in 120 participants (10.3%); 96 had VI from URE (8.2%), 168 participants (14.4%) had URE without VI, and 878 (75.3%) had no or adequately corrected RE. A smaller percentage of participants with VI resulting from URE reported having a college degree, and a larger percentage reported income < $10 000 compared with participants with no or adequately corrected RE (3.2% vs. 14.2% [P = 0.02]; 45.5% vs. 21.6% [P < 0.0001], respectively). Visual function was lowest among participants with VI from URE, followed by those with URE without VI, and then those with no or adequately corrected RE (9-item National Eye Institute Visual Function Questionnaire composite score, 67.3 ± 19.6 vs. 77.0 ± 14.4 vs. 82.2 ± 13.3, respectively; P < 0.0001). In total, 71.2% (n = 830) ordered glasses for an average cost of $36.80 ± $32.60; 97.7% were satisfied with their glasses.

CONCLUSIONS

URE was the main cause of VI at 2 clinics serving low-income communities and was associated with reduced vision-related quality of life. An online optical store with lower prices made eyeglasses accessible to low-income patients.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Relationship between Unstable Housing, Food Insecurity, and Vision Status in the MI-SIGHT Community Eye Disease Screening Program

PURPOSE

Assess rate of visual impairment (VI) from uncorrected refractive error (URE) and associations with demographic and socioeconomic factors among low-income patients presenting to the Michigan Screening and Intervention for Glaucoma and Eye Health through Telemedicine (MI-SIGHT) program.

DESIGN

Cross-sectional study.

PARTICIPANTS

Adults ≥ 18 years without acute ocular symptoms.

METHODS

MI-SIGHT program participants received a telemedicine-based eye disease screening and ordered glasses through an online optical shop. Participants were categorized based on refractive error (RE) status: VI from URE (presenting visual acuity [PVA] ≤ 20/50, best corrected visual acuity [BCVA] ≥ 20/40), URE without VI (PVA ≥ 20/40, had ≥ 2 lines of improvement to BCVA), and no or adequately corrected RE (PVA ≥ 20/40, < 2 line improvement to BCVA). Patient demographics, self-reported visual function, and satisfaction with glasses obtained through the program were compared between groups using analysis of variance, Kruskal-Wallis, chi-square, and Fisher exact testing.

MAIN OUTCOME MEASURES

PVA, BCVA, and presence of VI (defined as PVA ≤ 20/50).

RESULTS

Of 1171 participants enrolled in the MI-SIGHT program during the first year, the average age was 55.1 years (standard deviation = 14.5), 37.7% were male, 54.1% identified as Black, and 1166 (99.6%) had both PVA and BCVA measured. VI was observed in 120 (10.3%); 96 had VI from URE (8.2%), 168 (14.4%) had URE without VI, and 878 (75.3%) had no or adequately corrected RE. A smaller percentage of participants with VI from URE reported having a college degree and a larger percentage reported income < $10 000 compared to participants with no or adequately corrected RE (3.2% versus 14.2%, P = 0.02; 45.5% versus 21.6%, respectively, P < 0.0001. Visual function was lowest among participants with VI from URE, followed by those with URE without VI, and then those with no or adequately corrected RE (VFQ9 composite score 67.3 ± 19.6 versus 77.0 ± 14.4 versus 82.2 ± 13.3, respectively; P < 0.0001). 71.2% (n = 830) ordered glasses for an average cost of $36.80 ± $32.60; 97.7% were satisfied with their glasses.

CONCLUSIONS

URE was the main cause of VI at 2 clinics serving low-income communities and was associated with reduced vision-related quality of life. An online optical shop with lower prices made eyeglasses accessible to low-income patients.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Social Deprivation and the Risk of Screening Positive for Glaucoma in the MI-SIGHT Telemedicine-Based Glaucoma Detection Program

PURPOSE

To assess whether increased poverty is associated with increased risk of screening positive for glaucoma or suspected glaucoma in a large public screening and intervention program.

DESIGN

Cross-sectional study from 2020 to 2022.

PARTICIPANTS

Adults ≥ 18 years old without acute ocular symptoms.

METHODS

Michigan Screening and Intervention for Glaucoma and eye Health through Telemedicine (MI-SIGHT) program participants' sociodemographic characteristics and area deprivation index (ADI) values were summarized from the clinical sites, which included a free clinic and a Federally Qualified Health Center (FQHC). The ADI, a composite measure of neighborhood deprivation (range, 1-10; 10 is worst deprivation), was assigned on the basis of the participants' addresses. Group comparisons were performed via 2-sample t tests or Wilcoxon Mann-Whitney tests for continuous measures and chi-square tests or Fisher exact tests with Monte Carlo simulation for categorical measures; Holm adjustment was used for multiple comparisons.

MAIN OUTCOME MEASURES

Risk factors for screening positive for glaucoma or suspected glaucoma.

RESULTS

Of the 1171 enrolled participants, 1165 (99.5%) completed the screening: 34% at the free clinic and 66% at the FQHC. Participants were on average aged 55.1 ± 14.5 years, 62% were women, 54% self-reported as Black/African-American, 34% White, 10% Hispanic or Latino, and 70% earned < $30 000 annually. The mean ADI was 7.2 ± 3.1. The FQHC had higher (worse) ADI than the free clinic (free clinic: 4.5 ± 2.9, FQHC: 8.5 ± 2.1, P < 0.0001). One-quarter (24%) of participants screened positive for glaucoma or suspected glaucoma. Screening positive for glaucoma or suspected glaucoma was associated with being older (P = 0.01), identifying as Black/African-American (P = 0.0001), having an established eyecare clinician (P = 0.0005), and not driving a personal vehicle to the appointment (P = 0.001), which is a proxy for increased poverty. Participants who screened positive had worse ADI than those who screened negative (7.7 ± 2.8 vs. 7.0 ± 3.2, P = 0.002). A larger percentage of White participants screened positive at the FQHC compared with White participants at the free clinic (21.3% vs. 12.3%, P = 0.01). FQHC White participants had worse ADI than free clinic White participants (7.5 ± 2.5 vs. 3.7 ± 2.7, P < 0.0001).

CONCLUSIONS

Personal poverty, assessed as not driving a personal vehicle to the appointment, and neighborhood-level poverty were both associated with increased rates of screening positive for glaucoma or suspected glaucoma.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Engagement in the Michigan Screening and Intervention for Glaucoma and Eye Health through Telemedicine Program: Comparing the Effect of Clinic versus Community-Based Recruitment Strategies

PURPOSE

To determine the effectiveness of adding community-based recruitment to clinic-based recruitment to engage participants in a glaucoma detection program.

DESIGN

Prospective cohort study.

SUBJECTS

Anyone ≥ 18 years of age who does not meet exclusion criteria.

METHODS

The Michigan Screening and Intervention for Glaucoma and Eye Health through Telemedicine (MI-SIGHT) program tests a novel way of improving glaucoma detection in communities with populations at high risk for disease, including people who identify as Black and Hispanic and those living with low socioeconomic status. The MI-SIGHT program is conducted in a free clinic (Ypsilanti, MI) and in a federally qualified health center (FQHC) (Flint, MI). Community engagement methods were used to identify outreach strategies to enhance recruitment. Participants were asked "How did you hear about the MI-SIGHT program?" and responses were summarized overall and by clinic and compared between clinic-based and community-based recruitment strategies.

MAIN OUTCOME MEASURES

Proportion recruited by location, within or outside of the clinic.

RESULTS

In total, 647 participants were recruited in the first 11 months of the study, 356 (55.0%) at the free clinic over 11 months and 291 (45.0%) at the FQHC over 6 months. Participants were on average 54.4 years old (standard deviation = 14.2); 60.9% identified as female, 45.6% identified as Black, 37.8% identified as White, 9.6% identified as Hispanic, and 10.9% had less than high school education. Participants reported hearing about the MI-SIGHT program from a clinic phone call (n = 168, 26.1%), a friend (n = 112, 17.4%), nonmedical clinic staff (n = 100, 15.5%), a clinic doctor (n = 77, 11.9%), an in-clinic brochure or flyer (n = 51, 7.9%), a community flyer (n = 44, 6.8%), the clinic website or social media (n = 28, 4.3%), or an "other" source (n = 65, 10.1%). Recruiting from the community outside the medical clinics increased participation by 265% at the free clinic and 46% at the FQHC.

CONCLUSIONS

The Community Advisory Board recommendation to use community-based recruitment strategies in addition to clinic-based strategies for recruitment resulted in increased program participation.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

A practical approach to continuous glucose monitoring (rtCGM) and FreeStyle Libre systems (isCGM) in children and young people with Type 1 diabetes

Real-time continuous glucose monitoring (rtCGM) and FreeStyle Libre glucose monitoring systems (isCGM) are new evolving technologies used in the management of Type 1 diabetes. They offer potential to improve diabetes control and reduce hypoglycaemia. rtCGM can be linked to insulin pump providing hybrid closed loop therapy. Families of children and young people are keen to have the benefit from these technologies. These are relatively expensive so it is important that health care professionals, families of children and young people (CYP) with diabetes are adequately trained in the use of these devices. Health care professionals need to be able to make patient selection based on individual needs and preferences to achieve maximum benefit. Association of Children's Diabetes Clinicians (ACDC) developed a comprehensive guideline in 2017 to help identify which patients may be most likely to benefit and how these technologies may be practically implemented. Since then new technologies have been introduced and the use of GCM has expanded in routine clinical practice. This article, aims to provide a practical approach and help identify which patients may be most likely to benefit and how the technology may be implemented in order to maximise the clinical benefits.

Michigan Screening and Intervention for Glaucoma and Eye Health Through Telemedicine (MI-SIGHT): Baseline Methodology for Implementing and Assessing a Community-based Program

PRECIS

The Michigan Screening and Intervention for Glaucoma and eye Health through Telemedicine (MI-SIGHT) program leverages community-engaged research, telemedicine, and health coaching to overcome key logistical and psychosocial barriers to improve glaucoma screening in underserved communities.

PURPOSE

To describe the methodology of the implementation and evaluation of the MI-SIGHT Program.

METHODS

The MI-SIGHT Program uses community engagement, telemedicine, and health coaching to overcome key logistical and psychosocial barriers to glaucoma identification and care among underserved populations. The MI-SIGHT Program will be evaluated in 2 community clinics: Hamilton Community Health Network, a federally qualified health center in Flint, Michigan, and the Hope Clinic, a free clinic in Ypsilanti, Michigan. A Community Advisory Board including the research team and health care providers, administrators, and patients from both clinics will guide program implementation. An ophthalmic technician at the community clinics will conduct screening tests for glaucoma and eye disease. The data will be transmitted through electronic health record to be reviewed by an ophthalmologist who will make recommendations for follow-up care. The ophthalmic technician will conduct a return visit to fit low-or no-cost glasses, help arrange follow-up with an ophthalmologist, and provide education. Those diagnosed with glaucoma or suspected glaucoma will be randomized to standard education or personalized glaucoma education and coaching. Costs will be assessed.

RESULTS

The authors hypothesize that the MI-SIGHT Program will detect a higher prevalence rate of glaucoma than that found in the general population, improve upon presenting visual acuity, enhance vision-related quality of life, and demonstrate that personalized glaucoma education and coaching improve adherence to follow-up care.

CONCLUSION

The MI-SIGHT Program may serve as a model for glaucoma screening and care in high-risk communities.

Do we need both cognitive and behavioural components in interventions for depressed mood in people with mild intellectual disability?

BACKGROUND

A growing literature suggests that people with mild intellectual disability (ID) who have depressed mood may benefit from cognitive-behavioural interventions. There has been some speculation regarding the relative merit of the components of this approach. The aim of this study was to compare (i) cognitive strategies; (ii) behavioural strategies; and (iii) combined cognitive-behavioural (CB) strategies on depressed mood among a sample of 70 individuals with mild ID.

METHODS

Staff from three participating agencies received training in how to screen individuals with mild ID for depressive symptoms and risk factors for depression. Depressive symptoms and negative automatic thoughts were assessed prior to and at the conclusion of the intervention, and at 6-month follow-up. The interventions were run in groups by the same therapist.

RESULTS

A post-intervention reduction in depression scores was evident in participants of all three interventions, with no significant difference between groups. A significant reduction in negative automatic thoughts post-intervention was evident in the CB combination group and was maintained at follow-up. Examination of clinical effectiveness suggests some advantage of the CB combination in terms of improvement and highlights the possible short term impact of behavioural strategies in comparison with the longer-term potential of cognitive strategies.

CONCLUSIONS

The findings support the use of group cognitive-behavioural interventions for addressing symptoms of depression among people with ID. Further research is necessary to determine the effectiveness of components.

Acute, 2-week, and 13-week inhalation toxicity studies on dimethylethoxysilane vapor in Fischer 344 rats

Dimethylethoxysilane (DMES), a volatile liquid, is used by NASA to waterproof the heat-protective silica tiles and blankets on the Space Shuttle. Acute, 2-wk, and 13-wk inhalation exposures to DMES vapor were conducted in male and female Fischer 344 rats. In the acute study, rats were exposed to 4000, 2000, 1000, 500, or 0 (control) ppm DMES for 4 h and observed for 14 days. There were no deaths. Narcosis and ataxia were observed in rats of the two highest concentrations only. These signs disappeared within 1 h following exposure. There were no DMES-related gross or microscopic tissue lesions in rats of all exposure groups. In the 2-wk study, rats were exposed for 6 h/day, 5 days/wk to 3000, 1000, 300, 100, or 0 ppm DMES. During exposure, narcosis was observed in rats of the 3000 and 1000 ppm groups. There was a mild decrease in body weight gain in rats of the 3000 ppm group. A decrease in platelet count, an increase in bile acids, and reduced weights of the thymus, testis, and liver were observed in rats of the 3000 ppm group. Microscopically, hypospermatogenesis and spermatid giant cells were observed in the seminiferous tubules of the testes of rats exposed to 3000 ppm DMES. In the 13-wk study, rats were exposed 6 h/day, 5 days/wk to 2000, 600, 160, 40, or 0 ppm DMES. During exposure, rats of the 2000 ppm group exhibited mild narcosis and loss of startle reflex. Recovery from these central nervous system signs was rapid. Body weights were mildly decreased for rats of the 2000 ppm group. There were no exposure-related effects in hematology, serum chemistry, or urinalysis. Female rats of the 2000 ppm group had delayed estrous cycles (6 days compared to 5 days in control rats). Noteworthy organ weight changes in rats of the 2000 ppm group included decreases in thymus, liver, and testicular weights; however, pathologic lesions were observed in the testes only. Sperm motility, epididymal sperm count, and testicular spermatid count were dramatically reduced. Microscopic lesions included degeneration of the seminiferous tubular cells, pyknosis or absence of germ cells, and hypospermia in the epididymis. Rats of the 600 ppm group had a slight decrease in thymic weight and a transient decrease in body weight. Results of the acute, 2-wk, and 13-wk inhalation studies indicate DMES concentrations of 1000 ppm and higher produce narcosis that rapidly disappears following exposure. Repeated exposure of rats to DMES at either 3000 ppm for 2 wk or 2000 ppm for 13 wk caused testicular atrophy and hypospermia in male rats. Female rats exposed to 2000 ppm for 13 wk had delayed estrous cycles. Toxicological effects in rats of the 600 ppm group were minimal and equivocal. The 160 ppm concentration was a no-observable-effect level (NOEL) for 13 wk of exposure to DMES.

Hormonal regulation of spermatogenesis in the hypophysectomized rat: FSH maintenance of cellular viability during pubertal spermatogenesis

The potential for follicle-stimulating hormone (FSH) to promote germ-cell survival and the cellular sites of FSH action were studied using a gonadally maturing (pubertal), hypophysectomized (Hx) rat model in which residual testosterone (T) activity was blocked by injections of an androgen-receptor antagonist, flutamide. Recombinant human FSH was given to androgen-deprived and androgen-blocked male rats at 27 days of age to determine maintenance of individual germ-cell types at 35 days of age. Follicle-stimulating hormone significantly increased testis weights and tubular diameters as compared with Hx and Hx-flutamide controls, although testis weights in FSH-treated animals were significantly lower than in pituitary-intact animals. Morphometric assays to determine ratios of germ cells to Sertoli cells and to determine the number of germ cells present per hour of development showed that the population of type A spermatogonia in the early stages of the cycle was not responsive to FSH. Follicle-stimulating hormone had a marked ability to maintain cell viability in the rapid, successive divisions that begin in the latter part of the cycle and that continue through the next cycle (i.e., from type A1 to A4 and from intermediate spermatogonia to type B spermatogonia to preleptotene spermatocytes to leptotene/zygotene spermatocytes to young pachytene spermatocytes). The data also suggest T responsiveness of these cell types since the Hx-FSH-flutamide group showed lower cell viability at the aforementioned steps when compared with the Hx-FSH group. Too few cell types were present at subsequent phases of spermatogenesis to allow a sensitive determination of FSH activity in the maintenance of cell viability. The data show the potential of FSH in the absence or relative absence of T activity to maintain cell viability. These data support the concept of overlapping and synergistic (or additive) effects of T and FSH in the immature rat and identify the cellular sites of FSH action.

Increased hypothalamic content of preproneuropeptide Y messenger ribonucleic acid in genetically obese Zucker rats and its regulation by food deprivation

Neuropeptide Y (NPY) is a potent orexigenic agent capable of producing hyperphagia and obesity. NPY-containing neurons project from the hypothalmic arcuate nucleus to the paraventricular nucleus, an area known to be sensitive to the orexigenic effects of NPY. In this study we investigated the possibility that preproNPY messenger RNA (mRNA) content may be altered in obese Zucker rats compared to that of their lean littermates. Total RNA was isolated from hypothalamic dissections from male and female, obese and lean Zucker rats. RNA was also isolated from dissections of: olfactory bulb, entorhinal cortex, hippocampus, and striatum of female obese and lean rats. PreproNPY mRNA content was determined by solution hybridization-RNase protection analysis. The results revealed a 2- to 3-fold increase in preproNPY mRNA levels in the hypothalamus of obese animals compared to lean. The increase was observed in both sexes and was specific to the hypothalamus. In situ hybridization localized this increase to the arcuate nucleus. An additional RNase protection study was pursued to investigate the effects of 72 h food deprivation on hypothalamic preproNPY mRNA levels in lean and obese animals. Lean animals displayed an approximate 2-fold increase in preproNPY mRNA content, whereas obese animals showed no significant increase after food deprivation. These data are consistent with the hypothesis that NPY projections within the hypothalamus are involved in regulating feeding behavior and weight gain, and that disturbed regulation of hypothalamic NPY expression may play a role in the etiology of obesity in the genetically obese Zucker rat.

Increased hypothalamic content of preproneuropeptide-Y messenger ribonucleic acid in streptozotocin-diabetic rats

Neuropeptide-Y (NPY) is a 36-amino acid C-terminally amidated peptide found within the hypothalamus that can potently stimulate carbohydrate feeding. Moreover, the hypothalamic content of NPY can be modulated by peripheral hetabolic status. To further evaluate the regulation of NPY synthesis in states of altered metabolic homeostasis, we measured the hypothalamic content of prepro-NPY mRNA in streptozocin (STZ)-diabetic, STZ-diabetic insulin-replaced, and control rats by both nuclease protection and in situ hybridization analyses. Adult male Sprague-Dawley rats received a single injection of STZ (100 mg/kg, ip) or citric acid (control). Beginning 72 h later one group of STZ-treated animals received daily injections of insulin (4 U Ultralente/day). All animals were killed 17-19 days after STZ or control treatment. STZ-treated animals were hyperglycernic and showed growth failure compared to control rats. Glycemic control was restored by insulin replacement, as was partial growth. Nuclease protection analysis revealed an approximately 3- to 4-fold increase in prepro-NPY mRNA levels in the samples from STZ-treated rats vs. control. This increase was returned to control values by insulin replacement. In situ hybridization analysis revealed the STZ-induced increase in hypothalamic prepro-NPY mRNA was detectable in the arcuate nucleus at levels that were in agreement with the nuclease protection results, but that NPY expression in other brain regions appeared to be either unaffected or decreased after STZ treatment. These data suggest that hypothalamic NPY expression is modulated by peripheral metabolic status and provide further explanation for the hyperphagia accompanying STZ-induced diabetes.

Use of a monoclonal antibody in differential diagnosis of children with haematuria and hereditary nephritis

In a retrospective, double-blind study, paraffin-embedded renal biopsy sections from 44 children with haematuria were examined to see whether a mouse monoclonal antibody (MCA-P1) against glomerular basement membrane (GBM) could identify a subgroup of patients with hereditary glomerulonephritis (Alport's syndrome) in whom the Goodpasture antigen was abnormal. There was strong linear binding of MCA-P1 to GBM in all of 29 patients with no evidence of hereditary nephritis and in 2 patients in whom the diagnosis of hereditary nephritis was thought possible but not definite on available clinicopathological evidence. In contrast, 12 of 13 patients with strong evidence of hereditary nephritis showed no binding (9) or greatly reduced binding (3). These findings suggest that a major subgroup of patients with hereditary glomerulonephritis have biochemical abnormalities of the GBM involving Goodpasture antigen and that MCA-P1 is useful in the differential diagnosis of children with haematuria.

A 2,4-dichlorophenyl diazonium-based method for total bilirubin without interference from indican in uremic sera

Comparison of total bilirubin quantification by a 2,4-dichlorophenyl diazonium method (2,4-DCPD) with a Jendrassik-Grof type of method showed excellent correlation for randomly selected sera. However, sera from uremic patients on chronic hemodialysis showed a marked positive bias for the 2,4-DCPD result as compared with the Jendrassik-Grof result. The mean difference was 5.3 mg/L, and resulted in about 20% of the hemodialysis patients having bilirubin values greater than 13 mg/L, the upper limit of our reference range. Indican in uremic sera reportedly reacts with certain diazo reagents, so we investigated indican's reactivity in the above methods. In vitro addition of indican caused no interference in the Jendrassik-Grof method, but produced a significant positive interference in the 2,4-DCPD method, 1 mmol of indican per liter appearing as about 36 mg of total bilirubin per liter. Long reaction times with the 2,4-DCPD reagent accentuate the problem. By shortening the reaction time with the 2,4-DCPD reagent to 1.7 min, we find that the indican interference can be eliminated, without affecting quantification of total bilirubin in either normal or uremic sera.

Urinary urea: are currently available methods adequate for revival of an almost abandoned test?

Measurement of urinary urea excretion has been suggested as a means of estimating nitrogen balance in hospitalized patients who are malnourished. Because proficiency-testing surveys show gross variations in mean urea as determined by various automated methods and extremely poor precision occasionally, we compared urinary urea measurements and ammonia interference in three widely used methods. The coupled urease/glutamate dehydrogenase method (used in the DuPont aca) showed positive interference from ammonia, as expected; with the diacetylmonoxime (Technicon (12/60) and the urease conductivity (Beckman ASTRA) methods we saw no such interference. Generally, interference by ammonia is less than 10%, but (rarely) it may exceed 25%. However, if urine specimens are properly diluted and potential sources of interference recognized, all three methods appear capable of providing clinically useful data.

Acute interstitial nephritis complicating Legionnaires' Disease

An acute interstitial nephritis was found in a patient with sudden renal failure and lung infection caused by Legionella pneumophilia. Our patient regained and maintained normal renal function after a short period of dialysis support. The diagnosis should be considered in any patient with a chest infection complicated by acute renal failure especially if confusion is disproportionate to the degree of uremia.

Amyloid P-component is a constituent of normal human glomerular basement membrane

Glomerular and other vascular basement membranes were found to contain an antigen that was immunochemically indistinguishable from serum amyloid P-component. There was no immunological cross-reactivity between antisera to serum amyloid P-component and to collagen types I, III, IV, or V. The amyloid P-component antigen was confined to the endothelial aspect, the lamina rara interna, of glomerular basement membrane. It could not be eluted by high-ionic-strength saline, EDTA, dithiothreitol, or either polar or nonpolar detergents, but was released into solution when isolated glomerular basement membrane was digested by highly purified bacterial collagenase. Most of these P-component molecules and their constituent polypeptide chains were of higher molecular weight and lower isoelectric point than serum amyloid P-component. These findings indicate that, as well as being a normal plasma protein and a universal constituent of amyloid deposits, P-component is also a normal matrix glycoprotein of basement membrane in which it is covalently linked to collagen and/or other matrix proteins. This may be relevant both to the pathogenesis of amyloidosis and to other aspects of physiology and pathology of basement membranes.

Renal isotransplantation without immunosuppression

Four renal isografts have been performed and all have had satisfactory function for 7 1/2 to 17 2/3 years without prophylactic or therapeutic immunosuppression. Three of these patients originally had glomerulonephritis, and in one there was histologic evidence of recurrent disease, 7 1/2 years after transplantation, without proteinura and without change in renal function. Although this experience is small, it suggests that prophylactic immunosuppression is not appropriate for recipients of renal isografts.

Mixed connective tissue disease with associated glomerulonephritis and hypocomplementaemia

Mixed connective tissue disease is an increasingly recognized entity in which renal disease is thought to be unusual and associated hypocomplementaemia even more uncommon. A patient is described who had both these features and who also illustrates many of the characteristic features of this syndrome. The response to steroids of the systemic sclerosis component is well shown and an additional feature of interest is the family history of other connective tissue diseases.