Low-risk pneumatosis intestinalis in the pediatric surgical population

BACKGROUND

Pneumatosis intestinalis (PI, presence of air in bowel wall) develops in a variety of settings and due to a variety of insults which is then characterized by varying severity and clinical course. Anecdotally, many of these cases are benign with few clinical sequelae; however, we lack evidence-based guidelines to help guide management of such lower-risk cases. We aimed to describe the clinical entity of low-risk PI, characterize the population of children who develop this form of PI, determine if management approach or clinical outcomes differed depending on the managing physician's field of practice, and finally determine if a shortened course of NPO and antibiotics was safe in the population of children with low-risk PI.

METHODS

We performed a retrospective review of all children over age 1 year treated at Children's Hospital Colorado (CHCO), between 2009 and 2019 with a diagnosis of PI who did not also have a diagnosis of cancer or history of bone marrow transplant (BMT). Data including demographic variables, clinical course, and outcomes were obtained from the electronic medical record. Low-risk criteria included no need for ICU admission, vasopressor use, or urgent surgical intervention.

RESULTS

Ninety-one children were treated for their first episode of PI during the study period, 72 of whom met our low-risk criteria. Among the low-risk group, rates of complications including hemodynamic decompensation during treatment, PI recurrence, Clostridium difficile colitis, and death did not differ between those who received 3 days or less of antibiotics and those who received more than 3 days of antibiotics. Outcomes also did not differ between children cared for by surgeons or pediatricians.

CONCLUSIONS

Here, we define low-risk PI as that which occurs in children over age 1 who do not have a prior diagnosis of cancer or prior BMT and who do not require ICU admission, vasopressor administration, or urgent surgical intervention. It is likely safe to treat these children with only 3 days of antibiotic therapy and NPO.

LEVEL OF EVIDENCE

Level III.

Gastrointestinal quality of life and bowel function in adults born with anorectal malformation and hirschsprung disease

PURPOSE

To assess the quality of life and disease-specific functioning of adults with anorectal malformations (ARM) or Hirschsprung disease (HD) compared to healthy reference scores.

METHODS

Patients with the diagnosis of ARM or HD from the Adult Colorectal Research Registry completed the Short Form 36 Health Survey (SF-36), the Gastrointestinal Quality of Life Index (GIQoLI), and the Bowel Function Score (BFS) between October 2019 and August 2022. One-sample Wilcoxon test compared the results to reported healthy references with a significance level of < 0.05.

RESULTS

The response rate was 67%. All three surveys were completed by 133 adults with a slight preponderance of males (51%). Median age was 31 years, 117 were born with ARM and 16 with HD. All subgroups had significantly lower BFS than healthy references. ARM patients scored significantly lower than the healthy reference population when assessed for GIQoL. All showed significant impairment with the mental component summary (MCS) of SF-36. Patients with a successful bowel management had significantly higher scores on all three questionnaires than those with fecal accidents.

CONCLUSION

Our results emphasize the importance of a successful bowel management and its impact on the quality of life and bowel function. Long-term follow-up is recommended with attention to mental health.

Fertility concerns and outcomes in females with anorectal malformations

PURPOSE

To assess fertility concerns and to describe pregnancy outcomes in patients with anorectal malformations (ARM).

METHODS

This is an IRB approved, cross-sectional study of patients in the Adult Colorectal Research Registry who completed reproductive health surveys between November 2021 and August 2022. Patients assigned female at birth with age 18 or older and ARM were included.

RESULTS

Sixty-four patients with ARM, age 18 or older, were included. Fertility concerns were reported in 26 (40.6%) patients, 11 of which had seen a fertility specialist, including four who had not yet tried to conceive. Fertility concerns were highest amongst cloaca patients who had not yet tried to conceive (37.5%). 26 (40.6%) patients had tried to conceive, of which 16 (25%) reported fertility problems, most frequently uterine abnormalities and damaged or blocked fallopian tubes. 22 (34.4%) participants were able to conceive and 18 (28.1%) had at least one live birth. Patients with ARM who had concerns of fertility, had better FertiQoL when compared to published reference scores for patients experiencing fertility issues.

CONCLUSION

Providers should be aware of fertility concerns in patients with ARM. Proactive counseling with referrals to a fertility specialist should be considered in patients who desire future fertility.

Incidence of medullary thyroid carcinoma and Hirschsprung disease based on the cosmos database

PURPOSE

Multiple endocrine neoplasia Type 2A (MEN2A) can occur with Hirschsprung disease (HD) due to mutation in the RET proto-oncogene, with the majority developing medullary thyroid carcinoma (MTC). Given the comorbidity, many parents have contacted us to share concerns and unfortunate experiences about the prevalence rates of MEN2A/MTC in patients with HD. The aim is to determine the prevalence rate of patients with HD and MEN2A or medullary thyroid carcinoma, respectively.

METHODS

This is a cross-sectional study of the COSMOS database from January 01, 2017, to March 08, 2023. The database was searched for patients diagnosed with MEN2A, MTC, and HD. IRB exemption was provided (COMIRB #23-0526).

RESULTS

The database contained 183,993,122 patients from 198 contributing organizations. The prevalence of HD and MEN2A was 0.00002%, and for HD and MTC was 0.000009%. One in 66 patients (1.5%) with MEN2A also had HD. One in 319 patients (0.3%) in the HD group had MEN2A. One in 839 patients (0.1%) within the HD population had MTC.

CONCLUSION

The prevalence of MTC and HD or MEN2A and HD in the study population was low. Considering that almost all MEN2A patients have a positive family history, this data does not support the general genetic testing of HD patients.

What is the role of neutropenia in pediatric cancer patients with pneumatosis intestinalis?

BACKGROUND

We aimed to identify prognostic indicators in pneumatosis intestinalis (PI) in a pediatric oncology population. We hypothesized that neutropenia would be an independent risk factor for adverse outcomes, including the need for abdominal operation to treat PI and for the development of recurrent PI.

METHODS

We performed a retrospective review of all patients treated for PI between 2009 and 2019 with a diagnosis of cancer or history of bone marrow transplant (BMT).

RESULTS

Sixty-eight children were treated for their first episode of PI; 15 (22%) were not neutropenic at presentation; eight underwent urgent abdominal operation (12%). Patients with neutropenia were more likely to receive TPN, had a longer course of NPO, and received a longer course of antibiotics. Neutropenia at presentation was associated with a decreased risk of PI recurrence (40% vs 13%, p = 0.03). Children who required an abdominal operation were more likely to require vasopressors at diagnosis (50% vs 10%, p = 0.013).

CONCLUSIONS

Among pediatric cancer patients, need for vasopressors at the time of PI is a marker of severe PI, with increased likelihood of requiring operative intervention. The presence of neutropenia is associated with lower rates of PI recurrence.

LEVEL OF EVIDENCE

Level III.

A National Survey of U.S. Adolescent Sleep Duration, Timing, and Social Jetlag During the COVID-19 Pandemic

OBJECTIVES

To assess changes in duration, timing, and social jetlag in adolescent sleep during the COVID-19 pandemic and evaluate the impact of mood, physical activity, and social interactions on sleep.

STUDY DESIGN

An online survey queried adolescents' sleep before (through retrospective report) and during the initial phase of COVID-19 in May 2020. Adolescents (N = 3,494), 13-19 years old, in the United States (U.S.) answered questions about their current and retrospective (prior to COVID-19) sleep, chronotype, mood, and physical and social activities. Linear regression models were fit for time in bed, reported bed and wake times, and social jetlag during COVID-19, accounting for pre-COVID-19 values.

RESULTS

Total reported time in bed (a proxy for sleep duration) increased on weekdays by an average of 1.3 ± 1.8 hours (p < .001) during COVID-19, compared to retrospective report of time in bed prior to COVID-19. During COVID-19, 81.3% of adolescents reported spending 8 hours or more in bed on weekdays compared to only 53.5% prior to COVID-19. On weekdays, bedtimes were delayed on average by 2.5 hours and wake times by 3.8 hours during COVID-19 compared to prior to COVID-19. On weekends, bedtimes were delayed on average by 1.6 hours and waketimes by 1.5 hours (all p's < 0.001). Social jetlag of >2 hours decreased to 6.3% during COVID-19 compared to 52.1% prior to COVID-19. Anxiety and depression symptoms and a decline in physical activity during COVID-19 were associated with delayed bed and wake times during COVID-19.

CONCLUSIONS

During COVID-19, adolescents reported spending more time in bed, with most adolescents reporting 8 hours of sleep opportunity and more consistent sleep schedules. As schools return to in-person learning, additional research should examine how sleep schedules may change due to school start times and what lessons can be learned from changes that occurred during COVID-19 that promote favorable adolescent sleep.

Longitudinal assessment of anxiety and depression symptoms in U.S. adolescents across six months of the coronavirus pandemic

BACKGROUND

The present study aimed to describe anxiety and depression symptoms at two timepoints during the coronavirus pandemic and evaluate demographic predictors.

METHODS

U.S. high school students 13-19 years old completed a self-report online survey in May 2020 and November 2020-January 2021. The Patient-Reported Outcomes Measurement Information System (PROMIS) Pediatric Depression and Anxiety short forms queried depression and anxiety symptoms.

RESULTS

The final sample consisted of 694 participants (87% White, 67% female, 16.2 ± 1.1 years). Nearly 40% of participants reported a pre-pandemic depression diagnosis and 49% reported a pre-pandemic anxiety diagnosis. Negative affect, defined as both moderate to severe depression and anxiety PROMIS scores, was found in ~ 45% of participants at both timepoints. Female and other gender identities and higher community distress score were associated with more depression and anxiety symptoms. Depression symptoms T-score decreased slightly (- 1.3, p-value  ≤ 0.001).

CONCLUSION

Adolescent mental health screening and treatment should be a priority as the pandemic continues to impact the lives of youth.

Acute vaping in a golden Syrian hamster causes inflammatory response transcriptomic changes

E-cigarette vaping is a major aspect of nicotine consumption, especially for children and young adults. Although it is branded as a safer alternative to cigarette smoking, murine and rat models of subacute and chronic e-cigarette vaping exposure have shown many proinflammatory changes in the respiratory tract. An acute vaping exposure paradigm has not been demonstrated in the golden Syrian hamster, and the hamster is a readily available small animal model that has the unique benefit of becoming infected with and transmitting respiratory viruses, including SARS-CoV-2, without genetic alteration of the animal or virus. Using a 2-day, whole body vaping exposure protocol in male golden Syrian hamsters, we evaluated serum cotinine, bronchoalveolar lavage cells, lung, and nasal histopathology, and gene expression in the nasopharynx and lung through reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Depending on the presence of nonnormality or outliers, statistical analysis was performed by ANOVA or Kruskal-Wallis tests. For tests that were statistically significant (P < 0.05), post hoc Tukey-Kramer and Dunn's tests, respectively, were performed to make pairwise comparisons between groups. In nasal tissue, RT-qPCR analysis revealed nicotine-dependent increases in gene expression associated with type 1 inflammation (CCL-5 and CXCL-10), fibrosis [transforming growth factor-β (TGF-β)], nicotine-independent increase oxidative stress response (SOD-2), and a nicotine-independent decrease in vasculogenesis/angiogenesis (VEGF-A). In the lung, nicotine-dependent increases in the expression of genes involved in the renin-angiotensin pathway [angiotensin-converting enzyme (ACE), ACE2], coagulation (tissue factor, Serpine-1), extracellular matrix remodeling (MMP-2, MMP-9), type 1 inflammation (IL-1β, TNF-α, and CXCL-10), fibrosis (TGF-β and Serpine-1), oxidative stress response (SOD-2), neutrophil extracellular traps release (ELANE), and vasculogenesis and angiogenesis (VEGF-A) were identified. To our knowledge, this is the first demonstration that the Syrian hamster is a viable model of e-cigarette vaping. In addition, this is the first report that e-cigarette vaping with nicotine can increase tissue factor gene expression in the lung. Our results show that even an acute exposure to e-cigarette vaping causes significant upregulation of mRNAs in the respiratory tract from pathways involving the renin-angiotensin system, coagulation, extracellular matrix remodeling, type 1 inflammation, fibrosis, oxidative stress response, neutrophil extracellular trap release (NETosis), vasculogenesis, and angiogenesis.

Altered Immunoglobulin Repertoire and Decreased IgA Somatic Hypermutation in the Gut during Chronic HIV-1 Infection

Humoral immune perturbations contribute to pathogenic outcomes in persons with HIV-1 infection (PWH). Gut barrier dysfunction in PWH is associated with microbial translocation and alterations in microbial communities (dysbiosis), and IgA, the most abundant immunoglobulin (Ig) isotype in the gut, is involved in gut homeostasis by interacting with the microbiome. We determined the impact of HIV-1 infection on the antibody repertoire in the gastrointestinal tract by comparing Ig gene utilization and somatic hypermutation (SHM) in colon biopsies from PWH (n = 19) versus age and sex-matched controls (n = 13). We correlated these Ig parameters with clinical, immunological, microbiome and virological data. Gene signatures of enhanced B cell activation were accompanied by skewed frequencies of multiple Ig Variable genes in PWH. PWH showed decreased frequencies of SHM in IgA and possibly IgG, with a substantial loss of highly mutated IgA sequences. The decline in IgA SHM in PWH correlated with gut CD4+ T cell loss and inversely correlated with mucosal inflammation and microbial translocation. Diminished gut IgA SHM in PWH was driven by transversion mutations at A or T deoxynucleotides, suggesting a defect not at the AID/APOBEC3 deamination step but at later stages of IgA SHM. These results expand our understanding of humoral immune perturbations in PWH that could have important implications in understanding mucosal immune defects in individuals with chronic HIV-1 infection. IMPORTANCE The gut is a major site of early HIV-1 replication and pathogenesis. Extensive CD4+ T cell depletion in this compartment results in a compromised epithelial barrier that facilitates the translocation of microbes into the underlying lamina propria and systemic circulation, resulting in chronic immune activation. To date, the consequences of microbial translocation on the mucosal humoral immune response (or vice versa) remains poorly integrated into the panoply of mucosal immune defects in PWH. We utilized next-generation sequencing approaches to profile the Ab repertoire and ascertain frequencies of somatic hypermutation in colon biopsies from antiretroviral therapy-naive PWH versus controls. Our findings identify perturbations in the Ab repertoire of PWH that could contribute to development or maintenance of dysbiosis. Moreover, IgA mutations significantly decreased in PWH and this was associated with adverse clinical outcomes. These data may provide insight into the mechanisms underlying impaired Ab-dependent gut homeostasis during chronic HIV-1 infection.

Granzyme B+ CD4 T cells accumulate in the colon during chronic HIV-1 infection

Chronic HIV-1 infection results in the sustained disruption of gut homeostasis culminating in alterations in microbial communities (dysbiosis) and increased microbial translocation. Major questions remain on how interactions between translocating microbes and gut immune cells impact HIV-1-associated gut pathogenesis. We previously reported that in vitro exposure of human gut cells to enteric commensal bacteria upregulated the serine protease and cytotoxic marker Granzyme B (GZB) in CD4 T cells, and GZB expression was further increased in HIV-1-infected CD4 T cells. To determine if these in vitro findings extend in vivo, we evaluated the frequencies of GZB⁺ CD4 T cells in colon biopsies and peripheral blood of untreated, chronically infected people with HIV-1 (PWH). Colon and blood GZB⁺ CD4 T cells were found at significantly higher frequencies in PWH. Colon, but not blood, GZB⁺ CD4 T cell frequencies were associated with gut and systemic T cell activation and Prevotella species abundance. In vitro, commensal bacteria upregulated GZB more readily in gut versus blood or tonsil-derived CD4 T cells, particularly in inflammatory T helper 17 cells. Bacteria-induced GZB expression in gut CD4 T cells required the presence of accessory cells, the IL-2 pathway and in part, MHC Class II. Overall, we demonstrate that GZB⁺ CD4 T cells are prevalent in the colon during chronic HIV-1 infection and may emerge following interactions with translocated bacteria in an IL-2 and MHC Class II-dependent manner. Associations between GZB⁺ CD4 T cells, dysbiosis and T cell activation suggest that GZB⁺ CD4 T cells may contribute to gut HIV-1 pathogenesis.

Qualitative Differences Between the IFNα subtypes and IFNβ Influence Chronic Mucosal HIV-1 Pathogenesis

The Type I Interferons (IFN-Is) are innate antiviral cytokines that include 12 different IFNα subtypes and IFNβ that signal through the IFN-I receptor (IFNAR), inducing hundreds of IFN-stimulated genes (ISGs) that comprise the 'interferome'. Quantitative differences in IFNAR binding correlate with antiviral activity, but whether IFN-Is exhibit qualitative differences remains controversial. Moreover, the IFN-I response is protective during acute HIV-1 infection, but likely pathogenic during the chronic stages. To gain a deeper understanding of the IFN-I response, we compared the interferomes of IFNα subtypes dominantly-expressed in HIV-1-exposed plasmacytoid dendritic cells (1, 2, 5, 8 and 14) and IFNβ in the earliest cellular targets of HIV-1 infection. Primary gut CD4 T cells from 3 donors were treated for 18 hours ex vivo with individual IFN-Is normalized for IFNAR signaling strength. Of 1,969 IFN-regulated genes, 246 'core ISGs' were induced by all IFN-Is tested. However, many IFN-regulated genes were not shared between the IFNα subtypes despite similar induction of canonical antiviral ISGs such as ISG15, RSAD2 and MX1, formally demonstrating qualitative differences between the IFNα subtypes. Notably, IFNβ induced a broader interferome than the individual IFNα subtypes. Since IFNβ, and not IFNα, is upregulated during chronic HIV-1 infection in the gut, we compared core ISGs and IFNβ-specific ISGs from colon pinch biopsies of HIV-1-uninfected (n = 13) versus age- and gender-matched, antiretroviral-therapy naïve persons with HIV-1 (PWH; n = 19). Core ISGs linked to inflammation, T cell activation and immune exhaustion were elevated in PWH, positively correlated with plasma lipopolysaccharide (LPS) levels and gut IFNβ levels, and negatively correlated with gut CD4 T cell frequencies. In sharp contrast, IFNβ-specific ISGs linked to protein translation and anti-inflammatory responses were significantly downregulated in PWH, negatively correlated with gut IFNβ and LPS, and positively correlated with plasma IL6 and gut CD4 T cell frequencies. Our findings reveal qualitative differences in interferome induction by diverse IFN-Is and suggest potential mechanisms for how IFNβ may drive HIV-1 pathogenesis in the gut.

Why Delay? Early Enteral Nutrition in Pediatric Burn Patients Improves Outcomes

Children who sustain moderate to large surface area burns present in a hypermetabolic state with increased caloric and protein requirements. A policy was implemented at our institution in 2017 to initiate enteral nutrition (EN) in pediatric burn patients within 4 hours of admission. The authors hypothesize that early EN (initiated within 4 hours of admission) is more beneficial than late EN (initiated ≥ 4 hours from admission) for pediatric burn patients and is associated with decreased rates of pneumonia, increased calorie and protein intake, fewer feeding complications, a shorter Intensive Care Unit (ICU) length of stay (LOS), and a reduced hospital LOS. Children who sustained a total body surface area (TBSA) burn injury ≥ 10% between 2011 and 2018 were identified in a prospectively maintained burn registry at Children's Hospital Colorado. Patients were stratified into two groups for comparison: early EN and late EN. The authors identified 132 pediatric burn patients who met inclusion criteria, and most (60%) were male. Approximately half (48%) of the study patients were in the early EN group. The early EN group had lower rates of underfeeding during the first week (P = .014) and shorter ICU LOS (P = .025). Achieving and sustaining adequate nutrition in pediatric burn patients with moderate to large surface area burn injuries are critical to recovery. Early EN in pediatric burn patients is associated with decreased underfeeding and reduced ICU LOS. The authors recommend protocols to institute feeding for patients with burns ≥ 10% TBSA within 4 hours of admission at all pediatric burn centers.

Neuron-Specific Enolase

The clinical value of neuron-specific enolase as a marker in small cell lung cancer, neuroblastoma, melanoma and seminoma has been reviewed The role of serum and cerebrospinal NSE in benign and malignant disease of the central nervous sytem is discussed.

The Tumour Marker CA 195 in Colorectal and Pancreatic Cancer

The aim of this study was to measure the serum level of the tumour markers CA 195 and CEA in patients with either colorectal or pancreatic cancer both before and at serial intervals after operation. CA 195 and CEA were measured in 199 patients with colorectal cancer and 52 patients with pancreatic cancer. The median concentrations of CA 195 were 3.0 u/ml (interquartile range 3.0-4.5 u/ml) in patients with a Dukes’ stage A lesion, 5.8 u/ml (3.0-18.2 u/ml) in patients with a Dukes’ stage B lesion, 6.1 u/ml (3.0-24.7 u/ml) in patients with a Dukes’ stage C and 23.8 u/ml (11.1-409.0 u/ml) in patients with metastatic disease (normal range 0-7 u/ml). The median levels of CEA were 2.6 ng/ml (1.7-3.3 ng/ml) for Dukes’ stage A, 3.3 ng/ml (1.7-7.2 ng/ml) for Dukes’ stage B, 3.7 ng/ml (2.2-7.9 ng/ml) for Dukes’ stage C and 34.5 ng/ml (13.3-289.4 ng/ml) for metastatic disease. A rising level of CA 195 or CEA after operation suggested recurrence of the tumour. In none of these patients was the recurrence operable. In patients with pancreatic adenocarcinoma, the level of CA 195 was significantly higher in patients with metastatic disease but it did not discriminate between resectable and unresectable disease. The duration of survival correlated with the initial level of CA 195 (Rs = –0.66, p < 0.001).

Evaluation of CEA in Patients with known Residual Disease after Resection of Colonic Cancer

Serial carcinoembryonic antigen (CEA) levels were measured in 43 patients following incomplete excision of colorectal cancer. Twenty-seven patients received chemotherapy. In the majority the subsequent elevation of CEA could be related to clinical progression, but some patients receiving chemotherapy may have a suppressed rate of CEA rise and may have a more prolonged survival.The clinical application of serial CEA estimations remains of dubious value. However, one area which may be worthy of study is to determine whether suppression of the CEA slope by chemotherapy is attended by clinical control and an improved survival.

Renal failure in myelomatosis

Renal failure is a common presenting feature in myelomatosis. This review offers a practical means for classifying renal failure in this disease. Three groups are identified: (1) those patients whose renal failure improves or is stable when they are maintained on a high fluid intake; (2) the minority of patients whose renal failure progresses despite high fluid intake; and (3) those patients who are fluid-intolerant due to oliguric renal failure or congestive cardiac failure. The difference between groups 1 and 2 is not simply due to differences in response to chemotherapy, for many group-1 patients achieve improvement in renal function without or before loss of light chain proteinuria. It is concluded that all patients with myelomatosis with excess monoclonal free light chain proteinuria are at risk from developing renal failure of the type associated with group 1. The chances of them doing so are diminished if they maintain a high fluid intake. Group 2 encompasses a range of conditions not all of which are clearly defined. There is generally a poor correlation between the physical characteristics of light chains and the presence of group-2 renal failure.

Prognostic indicators for the development of AIDS in HIV antibody positive haemophiliac patients: results of a three-year longitudinal study

In February 1986, 40 out of 75 adult patients with haemophilia A attending St. James's University Hospital were human immunodeficiency virus (HIV) antibody positive. Over a three-year period these patients were prospectively studied with regard to possible prognostic indicators for the development of the acquired immune deficiency syndrome (AIDS). Using the Centres for Disease Control (CDC) classification of HIV infection, 17 patients (42.5%) developed group 4 disease during this time, giving an actuarial three-year progression rate of 44%, and 5 patients (12.5%) died. The following parameters measured at recruitment were found independently to predict progression to AIDS: a serum beta 2-m level of greater than 3.5 mg/l, (chi 2 = 15.95, P less than 0.001), a serum IgA level of greater than 4.5 milligram(s) (chi 2 = 6.08, P less than 0.02) and p24 antigenaemia (chi 2 = 5.7, P less than 0.05). The actuarial three-year progression rate in those patients abnormal by two or more of these parameters was 100% (n = 7), compared to only 7% in patients who were normal by all three values (n = 15). CD4+ lymphocyte counts and CD4+:CD8+ ratios were significantly lower in HIV positive compared with HIV negative patients (P less than 0.01), but did not predict the development of AIDS.

Bone alkaline phosphatase in rheumatoid arthritis: a longitudinal study

OBJECTIVE

To determine whether the raised total alkaline phosphatase (TAP) found in patients with active rheumatoid arthritis (RA) is derived primarily from an increase of the bone or liver isoenzyme, and to evaluate the treatment effect of steroids and disease modifying antirheumatic drugs (DMARD) on bone alkaline phosphatase (BAP) in serial analyses.

METHODS

58 patients with RA were treated with the DMARD gold sodium thiomalate (n = 22), D-penicillamine (n = 18), or sulfasalazine (n = 18) over a 24 week period with regular assessment of disease activity and measurement of BAP using a newly developed specific double monoclonal radioimmunometric assay.

RESULTS

In the RA group as a whole, BAP correlated with TAP at all time points (e.g., Week 0 rs = 0.50, p < 0.0001). In contrast, no correlation was found between the intraindividual change of BAP and TAP between Weeks 4 and 24. TAP was correlated with disease activity (assessed by plasma viscosity rs = 0.33, p < 0.02 for the whole RA group and rs = 0.48, p < 0.0002 for intraindividual change from Weeks 4 to 24). Similarly, gamma-glutamyltranspeptidase was correlated with disease activity (rs = 0.56, p < 0.0001, and rs = 0.50, p < 0.0001, respectively). In contrast, BAP was not correlated with disease activity. Low dose steroids and the 3 DMARD studied had no significant effect on the time course of BAP.

CONCLUSION

In the majority of patients with active RA, any increase of TAP is not mirrored by an increase of BAP. This supports the hypothesis that inflammatory reactions result in an increase in the plasma concentration of the membrane bound enzymes of the hepatobiliary system, including gamma-glutamyltranspeptidase and the liver isoenzyme of alkaline phosphatase, which is likely to be responsible, at least in part, for the increase of TAP. Since BAP is not correlated with disease activity, BAP measurements are not useful in monitoring response to treatment.

Serum hyaluronan concentrations predict survival in patients with chronic renal failure on maintenance haemodialysis

BACKGROUND

Malnutrition and wasting are common in chronic renal failure and are adverse prognostic features. The underlying mechanisms are complex and not fully understood. Hyaluronan is present in increased concentrations in chronic renal failure and may be associated with adverse features of chronic renal failure.

METHODS

We have investigated the relationship of this abnormality to long-term survival. Outcome of 81 patients of median of 5.6 years (3.9-6.8) after measurement of hyaluronan was determined.

RESULTS

Survival analysis by the Cox regression model showed that increased concentrations of hyaluronan (P < 0.0001). There was also a weak but significant negative correlation between hyaluronan concentrations and serum albumin concentrations (rs = - 0.27, P = 0.02).

CONCLUSIONS

We conclude that serum hyaluronan is a strong independent predictor of long-term survival in CRF may reflect abnormal connective tissue metabolism in this condition.

Bone alkaline phosphatase in rheumatic diseases

A double monoclonal immunoradiometric assay specific for bone alkaline phosphatase (BAP) was used to determine whether the raised total alkaline phosphatase (TAP) often found in patients with active rheumatoid arthritis (RA) and ankylosing spondylitis (AS) is derived from bone or liver. Fifty-eight patients with RA were compared to 14 with AS and 14 with non-inflammatory rheumatic diseases (NI). None had clinical liver disease and only one had a slightly elevated aspartate transaminase activity. Elevated BAP concentrations were found in seven patients (5 RA, 1 AS, 1 NI), only two of whom also had abnormal TAP. Abnormal TAP activities were found in only three patients (all RA). BAP did not correlate with disease activity in RA or AS. In contrast, TAP correlated with disease activity (assessed by plasma viscosity) in RA (P < 0.002) and gamma-glutamyl transferase (GGT) also correlated with plasma viscosity in RA (P < 0.01). Both TAP and BAP were significantly correlated with GGT in RA (P < 0.001 and P < 0.02, respectively). These findings are discussed, together with possible reasons for the conflicting nature of some of the observations.

Neuron-specific enolase (NSE) in serum. Comparison of monoclonal versus polyclonal assay based on 392 blood samples

Neuron-specific enolase (NSE) is the best described serum tumor marker for small cell lung cancer (SCLC). Almost all clinical studies carried out so far used assays involving polyclonal antibodies against NSE; the majority of the studies analyzed the samples by a RIA NSE kit. We evaluated a new monoclonal kit and compared it to the polyclonal kit. We analyzed 392 serum samples, 265 from patients with SCLC, 88 from non-small cell lung cancers (NSCLC) and 39 from children with neuroblastomas. We found a good correlation between the results of the two assays. When correlating NSE in SCLC as measured with the two assays with clinical data, we found the same sensitivity, prognostic impact and value in treatment monitoring. We conclude that the "new" monoclonal assay is a fully acceptable alternative to the "old" polyclonal assay.

Bone alkaline phosphatase and prostate-specific antigen in the monitoring of prostate cancer

A retrospective study has been made on the interrelationship of serum bone alkaline phosphatase (BAP), measured by the Ostase-RIA, and prostate-specific antigen (PSA) in 156 patients with M0 and M1 prostate cancer. BAP is a more sensitive and more specific method of determining osteoblast activity than total alkaline phosphatase (TAP). The main difference between these two assays is seen when the TAP is in the range of normal to twice-normal. BAP shows a low intraindividual variation in M0 disease, and was within normal limits in 18 patients following radical prostatectomy with a PSA < 0.1 ng/ml. A raised BAP was observed in 86.4% of M1 disease at diagnosis before treatment. The change of BAP was concordant with PSA in 69% of 49 cases of M1 disease, although there are marked differences in the rates of change of the two markers. A nadir of PSA < or = 10 ng/ml after androgen blockade in M1 disease was associated with a high probability of a normal BAP.

Serum neuron-specific enolase (S-NSE) in progressive small-cell lung cancer (SCLC)

Clinical decision making is based on results from qualitative and quantitative information. To provide quantitative data, various laboratory variables are widely used in the clinical evaluation of patients with small-cell lung cancer (SCLC). The tumour marker serum neuron-specific enolase (S-NSE) and the routine laboratory parameter serum lactate dehydrogenase (S-LDH) have been investigated, mostly separately. Few studies have compared their importance in SCLC, especially in progressive disease (PD). The present investigation was undertaken to evaluate S-NSE for diagnostic efficacy in PD and compare it with S-LDH. In 27 patients in a treatment trial of SCLC, regular follow-up laboratory values were prospectively obtained. Chemotherapy was given according to trial protocols, and all clinical evaluation followed the WHO recommendations. At re-evaluation all but three values had normalised (two S-NSE, one S-LDH). S-NSE at progression was increased in 93% of the patients and S-LDH in 59%. The efficacy of S-NSE to discriminate between response and PD was superior to S-LDH (0.92 vs 0.70). There was no additive effect of the two parameters in prediction of PD, and the discriminating power was higher for S-NSE than for S-LDH (P < 0.0008). The disease status-related marker increments in relation to upper reference limits, i.e. the signal-noise relation, were higher for S-NSE than for S-LD. Both of the markers carry information on PD. S-NSE is, however, clearly superior to S-LDH in reflecting disease status during therapy. This prompts us to conclude that S-NSE should replace S-LDH as prognostic factor and disease activity monitor in SCLC.

The role of CA-242 and CEA in surveillance following curative resection for colorectal cancer

This study was undertaken to evaluate the role of a new tumour marker, CA-242, alone or in combination with CEA in the practical management of colorectal cancer patients after potentially curative resection. A cohort of 149 patients who had undergone 'curative' surgery was followed up according to an intensive protocol in order to detect recurrent disease. Over a median tumour marker follow-up period of 24 months there were 25 recurrences in 24 patients. Both CEA and CA-242 alone detected half the local recurrences. The sensitivity of CEA was 84% for distant or mixed recurrence compared with 64% for CA-242. An abnormality of either CEA or CA-242 enabled detection of five out of six local recurrences and 17 out of 19 distant or mixed recurrences with a median lead time of 5 months for each marker. Both markers were elevated concurrently in only one local and 11 distant recurrences. While CA-242 alone is not superior to CEA, their combined use (either abnormal) has a high sensitivity (88%), specificity (78%) and negative predictive value (97%); this may be useful in reducing unnecessary investigations in follow-up programmes and as a guide to the initiation of further treatment for recurrent disease.

Commercial assays for serum osteocalcin give clinically discordant results

Serum samples from 9 healthy controls and from subjects with primary hyperparathyroidism (n = 5), Paget disease (n = 3), pregnancy (n = 5), glucocorticoid therapy (n = 5), postmenopausal osteoporosis (n = 10), and renal failure (n = 10) were used to assess the clinical agreement among eight commercially available assay kits for osteocalcin (OC). These kits differ in their assay configurations (six radioimmunoassays, two immunoradiometric assays), standards (five bovine, three human), and antibodies (six polyclonal, two monoclonal). Individual results were divided by the mean OC of the control subjects for each assay and expressed as percentage deviations. The expected wide variation in absolute OC concentrations between kits was only partially reduced by this transformation. Agreement was equally poor when absolute OC concentrations were compared with the reference ranges quoted by the manufacturers. The discordance was particularly marked in renal failure, presumably because of immunoreactive fragments, and in osteoporosis. Systematic differences could not be attributed to assay format, species source of standard, or antibody specificity. We conclude that results cannot be compared between assays even when normalized against healthy subjects, and that standardization is needed.

Commercial assays for serum osteocalcin give clinically discordant results

Serum samples from 9 healthy controls and from subjects with primary hyperparathyroidism (n = 5), Paget disease (n = 3), pregnancy (n = 5), glucocorticoid therapy (n = 5), postmenopausal osteoporosis (n = 10), and renal failure (n = 10) were used to assess the clinical agreement among eight commercially available assay kits for osteocalcin (OC). These kits differ in their assay configurations (six radioimmunoassays, two immunoradiometric assays), standards (five bovine, three human), and antibodies (six polyclonal, two monoclonal). Individual results were divided by the mean OC of the control subjects for each assay and expressed as percentage deviations. The expected wide variation in absolute OC concentrations between kits was only partially reduced by this transformation. Agreement was equally poor when absolute OC concentrations were compared with the reference ranges quoted by the manufacturers. The discordance was particularly marked in renal failure, presumably because of immunoreactive fragments, and in osteoporosis. Systematic differences could not be attributed to assay format, species source of standard, or antibody specificity. We conclude that results cannot be compared between assays even when normalized against healthy subjects, and that standardization is needed.

Clinical evaluation of serum tissue polypeptide-specific antigen (TPS) in non-small cell lung cancer

M3 is an epitope of the tissue polypeptide antigen detectable in the serum by immunoradiometric assay. This epitope is referred to as tissue polypeptide-specific antigen (TPS). We examined the pretreatment TPS level of 160 non-small cell lung cancer (NSCLC) patients and 71 patients who suffered from non-malignant pulmonary diseases. The upper limit of normal values was 140 U/l. Using this cutoff, the sensitivity and specificity were 36 and 90%, respectively. The TPS was significantly higher in NSCLC patients with an advanced stage, a mediastinal lymph node involvement or a poor performance status. This level was significantly higher in the group of patients for whom the disease proved to progress during chemotherapy. In univariate analysis, patients with a high TPS level proved to have a shorter survival than patients with a TPS < or = 140 U/l. In Cox's model analysis, performance status, stage of the disease and serum TPS were the only significant prognostic variables. The low sensitivity of TPS precludes its use for diagnosis. However, the pretreatment TPS level adds information to the management of NSCLC inasmuch as it predicts a low sensitivity to chemotherapy and a poor prognosis.

Clinical evaluation of serum tumour marker CA 242 in non-small cell lung cancer

CA 242, a novel tumour carbohydrate antigen present in serum (upper limit of normal values: 20.0 U ml-1), has been measured in a group of 102 pathologically confirmed non-small cell lung cancer patients. The aim of the present prospective study was to identify any relationship between pre-treatment serum CA 242 level and different features of lung cancer including prognosis. Serum CA 242 was measured using the delayed europium lanthanide fluoroimmunometric assay. Sensitivity and specificity were 28.5% and 95.6% respectively. Its level was significantly lower in squamous cell carcinoma in comparison with non-squamous histologies (adenocarcinoma and large cell carcinoma). The CA 242 level was higher in metastatic disease (median: 15.3 U ml-1) in comparison with non-metastatic (median: 7.9 U ml-1; Mann Whitney U test; P < 0.003), and increased significantly from stage I to stage IV. In 50 patients who underwent chemotherapy, the serum CA 242 level was higher in non-responder patients when compared with responders (median: 16.8 U ml-1 and 9.5 U ml-1 respectively; Mann Whitney; P < 0.02). Univariate analysis of the entire population showed serum CA 242 levels were not related to survival. However, patients with unresectable non-small cell lung cancer and elevated CA 242 level proved to have a significantly shorter survival than those with a CA 242 < 20 U ml-1. In Cox's model analysis, stage of the disease and performance status were the only significant determinants of survival. We conclude that a high level of serum CA 242 (1) is significantly related to the stage of disease, (2) predictive of no response to chemotherapy but seems to add weak prognostic information to stage of disease and performance status, the main prognostic determinants of non-small cell lung cancer.

The use of tumour markers CEA, CA-195 and CA-242 in evaluating the response to chemotherapy in patients with advanced colorectal cancer

Tumour markers CEA, CA-195 and CA-242 were measured in 33 patients undergoing chemotherapy for advanced colorectal cancer. The aim was to determine whether they could be used to accurately monitor the course of the disease, and reduce the need for imaging. Treatment with a 5-fluorouracil based regimen resulted in a partial response in nine patients (27%), whereas the remainder either had disease stabilisation or suffered from progression. Before treatment the CEA was elevated in 85% of patients and the CA-195 and CA-242 in 78%. All three markers were elevated in 70% and at least one elevated in 93%. CA-195 and CA-242 appeared to be co-expressed, by contrast with the CEA. When compared to the results of serial CT scanning the CEA correlated best with the course of the disease, the positive predictive value being 54% for a partial response, 77% for minor and partial responses combined and 100% for progressive disease. The corresponding values for CA-195 were 46%, 62% and 100% respectively and for CA-242, 50%, 67% and 100% respectively. Thus, although falling levels of markers overestimate the number of responses demonstrated by imaging, rising tumour markers invariably herald progressive disease. This was often evident up to 16 weeks before progression was observed on scanning. CEA is the most useful of the three markers in the monitoring of patients being treated for advanced colorectal cancer, but other markers may prove valuable if the CEA is normal. The use of tumour markers should reduce the need for regular scanning.

The prognostic value of the tumour markers CA 195 and CEA in patients with adenocarcinoma of the pancreas

The serum levels of CA 195 were determined in 52 patients with histologically proven pancreatic carcinoma and compared with carcino-embryonic antigen (CEA), serum bilirubin and albumin. CA 195 levels were raised above the upper limit of 20 U/ml in 42 cases, giving a sensitivity of 80% for the detection of pancreatic carcinoma, whereas CEA was raised in only 55%. The levels of CA 195 and CEA were significantly higher in patients with metastatic disease, but potentially curable cases were not discriminated. Bilirubin and albumin levels were not significantly related to either the presence of metastases or the levels of the tumour markers. At the time of initial presentation, levels of both tumour markers correlated with the eventual duration of survival, but bilirubin and albumin did not. Significant increases in CEA and CA 195 were found in sequential blood samples, as the disease progressed. Neither CA 195 nor CEA was of sufficient sensitivity to be of value for screening, but both give an indication of the presence of metastases and of the subsequent duration of survival. CA 195 appeared to be more sensitive and might help to assess progress of the disease.

Serum neuron specific enolase (NSE) is a determinant of response duration in small cell lung cancer (SCLC)

Seventy-two consecutive patients were eligible for a study of clinical determinants of response and response duration in small cell lung cancer (SCLC). Pretreatment values of routine laboratory parameters, and three tumour markers: neuron specific enolase (NSE), carcinoembryonic antigen (CEA), and acidic glycoprotein (AGP) were measured. Descriptive clinical variables as performance status (PS), extent of disease, age and sex were also included in the study. All variables were analysed for influence on the type and duration of response. The complete remission probability was only related to pretreatment extent of disease. In a multivariate analysis (Cox) of response duration, only NSE and type of response had significant influence. Consequently, measurements of NSE before therapy will be useful in future clinical trials on SCLC especially in situations, where responding patients are submitted to specific treatment strategies.

Tumor markers in prostate cancer

Prostatic specific antigen (PSA) is a tissue specific marker that is now the most widely used biochemical test for the assessment and follow-up of prostate cancer. The levels of PSA rise with tumor stage, but there is considerable overlap of their distribution between stages. PSA measurement now forms a part of the workup of a suspected carcinoma of the prostate, with a level of more than 4 ng/ml being an indication for further investigation. The sensitivity of PSA makes it an essential test for the postoperative assessment of radical prostatectomy and curative radiation therapy. The rates of change of PSA levels in locally advanced and metastatic disease treated by hormone manipulation can provide prognostic information. Low levels of PSA (less than 10 ng/ml) 6 months after treatment are a sign that the response will be prolonged. However, the sensitivity of PSA often results in a rising level preceding clinical evidence of progression by several months and is not necessarily an indication to change treatment. Alkaline phosphatase and prostatic acid phosphatase provide a less sensitive test for the bone response to skeletal metastases and tumor activity in advanced disease, respectively.

Serum bone alkaline phosphatase and CA 549 in breast cancer with bone metastases

A monoclonal radioimmunometric assay for bone alkaline phosphatase (BAP) developed by Hybritech, USA, with an upper limit of normal of 40 U/l, was examined in 125 patients with breast cancer. Eleven patients who remained tumour free for 5-6 years had small intra-individual variations of BAP. The median value in 33 patients with multiple bone metastases of 60 U/l was elevated when compared with that in 40 patients with no evidence of metastases (22 U/l) and 34 U/l in 16 with limited bone disease (1-2 hot spots). By contrast, only 2 out of 25 patients with extensive local recurrence, lung, or hepatic metastases, without bone involvement showed an increase of BAP (< 200 U/l). The BAP levels were compared to total alkaline phosphatase (TAP), the breast cancer marker CA 549 (HybriBREScan). Longitudinal studies of 15 patients with bony metastases showed that TAP and BAP were well correlated only when the TAP was elevated; CA 549 and BAP could vary independently. The main use of BAP in patients with bone metastases appears to be an aid to the monitoring of treatment; however, it is not significantly raised in limited bone metastases.

Serum hyaluronate as a marker of hepatic derangement in acute liver damage

Twenty patients with paracetamol(acetaminophen)-induced acute liver damage of varying severity were studied longitudinally with assessment of clinical state, standard liver function tests and radiometric hyaluronate (HYA) assay (Pharmacia). In patients (n = 6) who developed coma, HYA rose rapidly with clinical deterioration to reach a median value of 27,510 micrograms/l, 7 days post-ingestion, which was significantly higher (p less than 0.005) than in patients (n = 7) who exhibited only marked derangement of liver function tests without evidence of encephalopathy, HYA median value of 3240 micrograms/l. These peak values showed no correlation to the peak values of serum alanine aminotransferase (ALT). A third group of patients (n = 7) who were treated with N-acetyl cysteine, did not exhibit any evidence of liver failure and showed no significant rise in levels of HYA or ALT. The data demonstrate that HYA is a rapidly changing marker of liver derangement which appears to follow the clinical course of the patient. The increase to extremely high levels in patients with hepatic encephalopathy, suggests that there is a reversible defect in the hepatic endothelial cell HYA receptor, possibly due to endothelial cell damage or release of toxins from the necrotic liver.

Sodium dodecyl sulphate polyacrylamide gel electrophoresis patterns of proteinuria in various renal diseases of childhood

This study examined the potential of an automated electrophoretic system (PHASTSYSTEM, Pharmacia. Uppsala, Sweden) to distinguish patterns of proteinuria in children with various renal diseases. It proved possible to produce ready-to-read sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE) separation of 1 microliter of unconcentrated urine in 2 h. Glomerular, tubular and mixed patterns of proteinuria were identified. Steroid-responsive nephrotic syndrome (SRNS) was readily identified by strong bands of albumin and transferrin during relapses. In contrast, steroid-resistant nephrotic syndrome was associated with two additional bands of haptoglobin and IgG. Albumin dimers (Mr 120 kDa) were found in the active phase of the disease in the urine of 90% of children with SRNS. Patterns of tubular proteinuria were found in children with proximal renal tubular abnormalities. The presence of mixed patterns of glomerular and tubular proteinuria strongly suggest renal insufficiency. SDS PAGE electrophoresis can readily be applied in clinical practice. It may prove helpful in the diagnosis and management of children with renal diseases enabling correlation to be made between proteinuria, renal pathology and prognosis.

Use of mucin like cancer associated antigen (MCA) in the management of breast cancer

A study of the epithelial mucin marker MCA was made in 233 patients with breast cancer. Only 6% of 72 patients with Stage I-III disease had a raised MCA (greater than 15 U ml-1) when assessed following surgical treatment of the primary tumour. Raised levels of MCA occurred in one out of 20 (10%) patients with stable local recurrence, and six out of ten (60%) patients with progressive local recurrence. In 115 patients with metastases 89 (77%) had a raised MCA, tumour extent and disease activity both influenced the MCA level. The change of MCA level during the treatment of 11 cases of local recurrence and 55 cases of metastatic disease showed a 64 and 84% concordance respectively with the change in clinical status. Coincidental measurement of MCA and bone scans showed a raised MCA in one out of 63 (1.5%) patients with negative or equivocal scans, and 26 out of 35 (74%) with positive scans. MCA provides a useful marker for the monitoring of the treatment of local recurrence and metastatic disease, and an independent indicator of the effects of changes in treatment.

Renal tubular dysfunction in rheumatic diseases

Evidence of renal tubular dysfunction as defined by abnormal urinary levels of alpha 1 and beta 2 microglobulin with or without microalbuminuria was found in 47 (16.5%) of 285 patients with a variety of rheumatic diseases, compared with a prevalence of less than 1% in 500 healthy adults. Previous work from this unit has shown a prevalence of tubular dysfunction of 24% in patients with severe rheumatic disease admitted to hospital, probably associated with severe rheumatoid arthritis. Although our study confirms a high prevalence of renal tubular dysfunction, we have shown that it is related to age and intercurrent illness, particularly urinary tract infection, rather than to rheumatic disease or drug therapy, although it is possible drug therapy could add to a compound insult on ageing or damaged kidney.

Tumour markers in prostatic cancer

Prostate cancer is now the third commonest cancer in men. Extensive clinical trials comparing acid phosphatase, alkaline phosphatase (ALKP) and prostate specific antigen (PSA) have shown that PSA is the most sensitive and specific of the tumour markers available for prostate cancer. Caution is needed when comparing the results from different assay methods, there is no international standard for PSA. In the management of localised disease, radical treatment can reduce the PSA levels to less than 0.4 ng/ml, similar results can be obtained for a varying duration in patients sensitive to androgen withdrawal. Raised levels greater than 0.4 ng/ml after radical prostatectomy are indicative of residual disease. PSA is valuable in monitoring deferred treatment or the effects of hormone manipulation and give an indication of the prognosis and early warning of recurrence. In extensive metastatic disease the combination of PSA and ALP reflects the tumour activity. Less than 15 hot spots on the scintigram at presentation and a PSA less than 10 ng/ml 3 to 6 months after commencing treatment is associated with prolonged survival. The role of PSA in population screening for early prostatic cancer is uncertain; early results suggest it can be used in combination with digital rectal examination and ultrasonic examination of the prostate. The effect of a PSA decision level at 4 or 10 ng/ml has a considerable influence on the pick up rate.

Hyaluronic acid in end-stage renal failure treated by haemodialysis: clinical correlates and implications

Serum hyaluronic acid was measured in 176 adults and 15 children receiving regular dialysis therapy. Hyaluronic acid was elevated to greater than 80 micrograms/l in more than 90%, with median value 182 micrograms/l (range 39-898 micrograms/l). Concentrations did not correlate with serum creatinine, but showed a significant correlation with duration of dialysis and serum beta 2-microglobulin. Values greater than 400 micrograms/l were frequent in patients whose clinical condition deteriorated, but in others, hyaluronic acid remained stable over 4-15 months. Serum hyaluronic acid is mainly in a high-molecular-weight form, which in the presence of normal hepatic function suggests that there is a metabolic disorder involving connective tissue and/or vascular endothelium that increases with progressive loss of renal function. Hyaluronic acid may also be a biochemical marker of patients whose condition deteriorates despite renal replacement therapy.

Occurrence of neuron specific enolase in tumour tissue and serum in small cell lung cancer

An analysis has been made of the relationship between neuron specific enolase (NSE) in serum and immunohistochemically identified occurrence of NSE in the primary tumour in 56 patients with small cell lung cancer (SCLC). Patients were referred to the Finsen Institute for treatment during a period of 18 months. Forty-six tumours (82%) were NSE positive. To compare this staining with the occurrence of NSE in serum, a histological staining index (HSI) was established by semiquantitative gradation of the staining. No significant differences were found between distribution of serum NSE values in different HSI categories, and a high ranking in HSI was not associated with a high level of serum NSE. Both univariate and multivariate analysis selected serum NSE and not HSI as the most influential prognostic factor in SCLC.