A Balancing Act: A Systematic Review and Metasynthesis of Family-Focused Practice in Adult Mental Health Services

Parental mental illness is a major international public health concern given its implications for whole families, including children. Family-focused practice (FFP), an approach that emphasises a "whole-family" approach to care, provides an opportunity to mitigate the significant risks associated with parental mental health difficulties. The positive benefits associated with FFP have led to a shift in policy and practice towards prioritising FFP within adult mental health services. However, evidence suggests that FFP remains scarce and is not routine. Research has identified the important role of practitioners in facilitating FFP. The current review identified, synthesised and appraised the international qualitative literature examining adult mental health practitioners' implementation experiences of FFP. It aimed to provide an evidence-informed account of practitioner experiences of FFP delivery and to identify key recommendations to enhance future FFP outcomes in AMHS. Ovid Medline, PsycInfo, CINAHL plus, EMBASE and Web of Science Core Collection were searched systematically, in line with PRISMA guidance, up to January 2022. The Critical Appraisal Skills Programme (CASP) was used to undertake the quality appraisal prior to a thematic synthesis being conducted. The review was registered on PROSPERO. Nineteen papers, spanning 17 years of research with 469 practitioners, were included. Three main themes and 14 subthemes were developed, representing different aspects of practitioner experiences of FFP delivery. Practitioners' approach to FFP was variable and influenced by their beliefs about FFP, perceived roles and responsibilities, competence, service setting, and personal parenting status. Practitioners engaged in a balancing act to maintain a dual focus on their service-users and their children, to navigate powerful emotions, and consider multiple perspectives in a biomedical organisational structure that advocates individualised treatment. Although working together unified teams, a greater need for external interagency collaboration was identified. The use of strength-based approaches with clients and dedicated staff resources, within clear guidelines and frameworks, was reported to be necessary to maximise FFP delivery. This review proposes a complex FFP dynamic whereby practitioners engage in a constant balancing act between FFP stakeholders to achieve meaningful FFP outcomes for service-users and their families. Service recommendations are provided.

Clinical performance of methylation-based liquid biopsy test COLVERA after optimization of test interpretation rules

3546

Background: Clinical guidelines recommend surveillance for patients who complete primary treatment for colorectal cancer (CRC) with the aim of detecting recurrence when amenable to curative intent treatment. Currently recommended surveillance protocols, including imaging and CEA have limitations both in sensitivity and specificity, thus novel methods that detect circulating tumor DNA (ctDNA) have been introduced into clinical practice. COLVERA is a laboratory-developed, real-time PCR test that detects DNA methylation of BCAT1 and IKZF1 genes. These two genes are hypermethylated in 95% of CRC tissue and COLVERA showed improved sensitivity for detection of recurrent disease in comparison to CEA in several clinical populations. The current study evaluated the impact of optimizing the assay’s qualitative reporting method on actionability and clinical performance for recurrence detection in CRC surveillance setting. Methods: Two previously described cohorts of CRC patients (N=322 and N=144) who completed primary treatment and were undergoing surveillance were evaluated. Imaging and blood collections were performed at, or adjacent to, a standard of care visit. cfDNA was extracted from whole blood, bisulphite-treated and assayed in triplicates for BCAT1/IKZF methylation. Previously, any positive replicate of either target gene was reported as COLVERA “detected”. In the current study, COLVERA is “detected” when at least one replicate of IKZF1 or multiple replicates of either IKZF1 and/or BCAT1 are present. Sensitivity, specificity, and diagnostic odds ratio (DOR) for CRC recurrence detection from a single time-point blood sample was determined using radiological imaging as clinical reference standard. Results: In the first cohort (N=322), overall COLVERA test positivity was 6.5% (21/322) with a sensitivity of 59.3% (95% CI: 38.8 - 77.6) and specificity of 98.3% (96.1 - 99.5) for detecting recurrence at a time-point adjacent to imaging, representing improved specificity, from 91.5% (87.7 - 94.4%), with minimal decrease in sensitivity, from 63.0% (42.4 – 80.6). Similarly, in the second cohort (N=144) sensitivity was 62% (47.2 -75.4), compared to 66.0% (57.1 – 69.3) under the prior interpretation method, while specificity was 92.6% (85.3-97), compared to 90.4% (84.7 - 94.7). A high DOR of 84 (26 - 272) (previously 18 (7.6 – 44.4)) indicates that the revised COLVERA interpretation method is clinically more informative and differentiates with greater accuracy patients with and without the disease. Conclusions: This change in the COLVERA interpretation rule resulted in optimized clinical specificity with minimal impact on sensitivity. For an assay intended to aid in surveillance and early recurrence detection, improved accuracy allows the physician to have increased confidence in making actionable decisions based on test result, including further imaging or treatment.

Abstract IA23: Phospho-RNA-seq: A liquid biopsy approach for cell-free mRNA/lncRNA profiling

Measuring disease biomarkers in biofluids to detect and monitor pathophysiologic events in tissues has enormous appeal. While detecting specific DNA sequences in blood plasma has been successful in informing about the presence of cancers, viruses, and a range of pathogens, this approach does not provide gene expression information, which could reveal more detailed information about disease activity. Measuring cell-free RNA in plasma would provide such information and has the potential to be more sensitive, given that one DNA molecule in a cell gives rise often to thousands or more RNA molecules.

However, with the exception of microRNAs, broad sequencing of cell-free messenger RNA (mRNA) profiles in plasma has been generally challenging. We discovered that a major barrier to cell-free RNA sequencing from plasma is that the large majority of mRNAs are both fragmented and have modified phosphorylation states at their 5’ and 3’ ends that make them invisible to standard small RNA-seq methods. We present a modified RNA-seq methodology, called phospho-RNA-seq, which revealed thousands of mRNA in blood plasma. The key to this approach is (i) the incorporation of T4-polynucleotide kinase treatment to change the phosphorylation states at the RNA ends, and (ii) a stringent bioinformatics analysis pipeline to reduce false positive alignments.

Phospho-RNA-seq identified cohorts of gene transcripts in plasma, including ones expressed in a tissue-specific manner. As proof-of-concept validation of the approach for biomarker identification, we used phospho-RNA-seq to longitudinally profile plasma specimens collected from patients undergoing hematopoietic stem cell transplantation. We detected bone marrow-enriched and liver-enriched transcript sets in plasma, which tracked with bone marrow recovery and hepatic injury, respectively. By providing expanded access to the transcriptome in plasma and potentially other biofluids, phospho-RNA-seq enables the discovery of new cell-free RNA biomarker signatures for a wide variety of liquid biopsy applications.

Citation Format: Maria D. Giraldez, Ryan M. Spengler, Alton Etheridge, Annika J. Goicochea, Missy Tuck, Sung W. Choi, David J. Galas, Muneesh Tewari. Phospho-RNA-seq: A liquid biopsy approach for cell-free mRNA/lncRNA profiling [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr IA23.

Phospho-RNA-seq: a modified small RNA-seq method that reveals circulating mRNA and lncRNA fragments as potential biomarkers in human plasma

Extracellular RNAs (exRNAs) in biofluids have attracted great interest as potential biomarkers. Although extracellular microRNAs in blood plasma are extensively characterized, extracellular messenger RNA (mRNA) and long non-coding RNA (lncRNA) studies are limited. We report that plasma contains fragmented mRNAs and lncRNAs that are missed by standard small RNA-seq protocols due to lack of 5' phosphate or presence of 3' phosphate. These fragments were revealed using a modified protocol ("phospho-RNA-seq") incorporating RNA treatment with T4-polynucleotide kinase, which we compared with standard small RNA-seq for sequencing synthetic RNAs with varied 5' and 3' ends, as well as human plasma exRNA Analyzing phospho-RNA-seq data using a custom, high-stringency bioinformatic pipeline, we identified mRNA/lncRNA transcriptome fingerprints in plasma, including tissue-specific gene sets. In a longitudinal study of hematopoietic stem cell transplant patients, bone marrow- and liver-enriched exRNA genes were tracked with bone marrow recovery and liver injury, respectively, providing proof-of-concept validation as a biomarker approach. By enabling access to an unexplored realm of mRNA and lncRNA fragments, phospho-RNA-seq opens up new possibilities for plasma transcriptomic biomarker development.

Performance of multitarget stool DNA testing in African American patients

BACKGROUND

Multitarget stool DNA (mt-sDNA) is an approved method for colon cancer screening that is especially relevant for patients who cannot undergo colonoscopy. Although the test performance has been evaluated in a large clinical trial, it was limited to a predominantly white population. Given differences in the epidemiology and biology of colon cancer in African American individuals, the authors sought to compare the performance of mt-sDNA between racial groups.

METHODS

The authors prospectively identified patients aged ≥40 years who were referred for colonoscopy at an academic medical center and 2 satellite facilities. Prior to the colonoscopy, the authors collected stool for mt-sDNA and fecal immunochemical testing (FIT). They compared the sensitivity, specificity, and receiver operating characteristic curve between African American and white patients for the detection of advanced lesions or any adenoma.

RESULTS

A total of 760 patients were included, 34.9% of whom were African American. The prevalence of any adenoma (38.9% for African American patients and 33.9% for white patients) and that for advanced lesions (6.8% and 6.7%, respectively) were similar between groups. The overall sensitivities of mt-sDNA for the detection of advanced lesions and any adenoma were 43% and 19%, respectively, and the specificities were 91% and 93%, respectively. In general, mt-sDNA was more sensitive and less specific than FIT. When stratified by race, the sensitivity, specificity, and receiver operating characteristic curve area were similar between African American and white patients for both mt-sDNA and FIT.

CONCLUSIONS

Test performance characteristics of mt-sDNA were comparable in African American and white patients. Given the lower uptake of colonoscopy in African American individuals, mt-sDNA may offer a promising screening alternative in this patient population.

Evaluation of Patients with an Apparent False Positive Stool DNA Test: The Role of Repeat Stool DNA Testing

BACKGROUND

There is uncertainty as to the appropriate follow-up of patients who test positive on multimarker stool DNA (sDNA) testing and have a colonoscopy without neoplasia.

AIMS

To determine the prevalence of missed colonic or occult upper gastrointestinal neoplasia in patients with an apparent false positive sDNA.

METHODS

We prospectively identified 30 patients who tested positive with a commercially available sDNA followed by colonoscopy without neoplastic lesions. Patients were invited to undergo repeat sDNA at 11-29 months after the initial test followed by repeat colonoscopy and upper endoscopy. We determined the presence of neoplastic lesions on repeat evaluation stratified by results of repeat sDNA.

RESULTS

Twelve patients were restudied. Seven patients had a negative second sDNA test and a normal second colonoscopy and upper endoscopy. In contrast, 5 of 12 subjects had a persistently positive second sDNA test, and 3 had positive findings, including a 3-cm sessile transverse colon adenoma with high-grade dysplasia, a 2-cm right colon sessile serrated adenoma with dysplasia, and a nonadvanced colon adenoma (p = 0.045). These corresponded to a positive predictive value of 0.60 (95% CI 0.17-1.00) and a negative predictive value of 1.00 (95% CI 1.00-1.00) for the second sDNA test. In addition, the medical records of all 30 subjects with apparent false positive testing were reviewed and no documented cases of malignant tumors were recorded.

CONCLUSIONS

Repeat positive sDNA testing may identify a subset of patients with missed or occult colorectal neoplasia after negative colonoscopy for an initially positive sDNA. High-quality colonoscopy with careful attention to the right colon in patients with positive sDNA is critically important and may avoid false negative colonoscopy.

Rapid, ultra low coverage copy number profiling of cell-free DNA as a precision oncology screening strategy

Current cell-free DNA (cfDNA) next generation sequencing (NGS) precision oncology workflows are typically limited to targeted and/or disease-specific applications. In advanced cancer, disease burden and cfDNA tumor content are often elevated, yielding unique precision oncology opportunities. We sought to demonstrate the utility of a pan-cancer, rapid, inexpensive, whole genome NGS of cfDNA approach (PRINCe) as a precision oncology screening strategy via ultra-low coverage (~0.01x) tumor content determination through genome-wide copy number alteration (CNA) profiling. We applied PRINCe to a retrospective cohort of 124 cfDNA samples from 100 patients with advanced cancers, including 76 men with metastatic castration-resistant prostate cancer (mCRPC), enabling cfDNA tumor content approximation and actionable focal CNA detection, while facilitating concordance analyses between cfDNA and tissue-based NGS profiles and assessment of cfDNA alteration associations with mCRPC treatment outcomes. Therapeutically relevant focal CNAs were present in 42 (34%) cfDNA samples, including 36 of 93 (39%) mCRPC patient samples harboring AR amplification. PRINCe identified pre-treatment cfDNA CNA profiles facilitating disease monitoring. Combining PRINCe with routine targeted NGS of cfDNA enabled mutation and CNA assessment with coverages tuned to cfDNA tumor content. In mCRPC, genome-wide PRINCe cfDNA and matched tissue CNA profiles showed high concordance (median Pearson correlation = 0.87), and PRINCe detectable AR amplifications predicted reduced time on therapy, independent of therapy type (Kaplan-Meier log-rank test, chi-square = 24.9, p < 0.0001). Our screening approach enables robust, broadly applicable cfDNA-based precision oncology for patients with advanced cancer through scalable identification of therapeutically relevant CNAs and pre-/post-treatment genomic profiles, enabling cfDNA- or tissue-based precision oncology workflow optimization.

Collaborating to Compete: Blood Profiling Atlas in Cancer (BloodPAC) Consortium

The cancer community understands the value of blood profiling measurements in assessing and monitoring cancer. We describe an effort among academic, government, biotechnology, diagnostic, and pharmaceutical companies called the Blood Profiling Atlas in Cancer (BloodPAC) Project. BloodPAC will aggregate, make freely available, and harmonize for further analyses, raw datasets, relevant associated clinical data (e.g., clinical diagnosis, treatment history, and outcomes), and sample preparation and handling protocols to accelerate the development of blood profiling assays.

Integrated analysis of genetic variation and gene expression reveals novel variant for increased warfarin dose requirement in African Americans

Essentials Genetic variants controlling gene regulation have not been explored in pharmacogenomics. We tested liver expression quantitative trait loci for association with warfarin dose response. A novel predictor for increased warfarin dose response in African Americans was identified. Precision medicine must take into account population-specific variation in gene regulation.

SUMMARY

Background Warfarin is commonly used to control and prevent thromboembolic disorders. However, because of warfarin's complex dose-requirement relationship, safe and effective use is challenging. Pharmacogenomics-guided warfarin dosing algorithms that include the well-established VKORC1 and CYP2C9 polymorphisms explain only a small proportion of inter-individual variability in African Americans (AAs). Objectives We aimed to assess whether transcriptomic analyses could be used to identify regulatory variants associated with warfarin dose response in AAs. Patients/Methods We identified a total of 56 expression quantitative trait loci (eQTLs) for CYP2C9, VKORC1 and CALU derived from human livers and evaluated their association with warfarin dose response in two independent AA warfarin patient cohorts. Results We found that rs4889606, a strong cis-eQTL for VKORC1 (log10 Bayes Factor = 12.02), is significantly associated with increased warfarin daily dose requirement (β = 1.1; 95% confidence interval [CI] 0.46 to 1.8) in the discovery cohort (n = 305) and in the replication cohort (β = 1.04; 95% CI 0.33 -1.7; n = 141) after conditioning on relevant covariates and the VKORC1 -1639G>A (rs9923231) variant. Inclusion of rs4889606 genotypes, along with CYP2C9 alleles, rs9923231 genotypes and clinical variables, explained 31% of the inter-patient variability in warfarin dose requirement. We demonstrate different linkage disequilibrium patterns in the region encompassing rs4889606 and rs9923231 between AAs and European Americans, which may explain the increased dose requirement found in AAs. Conclusion Our approach of interrogating eQTLs identified in liver has revealed a novel predictor of warfarin dose response in AAs. Our work highlights the utility of leveraging information from regulatory variants mapped in the liver to uncover novel variants associated with drug response and the importance of population-specific research.

Rapid, ultra-low coverage copy number profiling of cell-free DNA as a precision oncology screening strategy in metastatic castration-resistant prostate cancer (mCRPC)

144

Background: Although cell free DNA (cfDNA) profiling by next generation sequencing (NGS) holds great promise for precision oncology, the inability to estimate tumor content a priori typically results in ultra-deep sequencing (e.g. 10,000x) based approaches—often at limited loci—to ensure accurate assessment of cfDNA samples where tumor content can be < 0.1%. However, a large subset of patients with advanced cancers, where most precision oncology is applied, have much greater cfDNA tumor content. Methods: Here we demonstrate the utility of a pan-cancer, rapid, inexpensive, whole genome NGS of cfDNA approach (PRINCe) on benchtop sequencers as a precision medicine screening strategy based on ultra-low coverage (~0.005x) tumor content determination through genome-wide copy number alteration (CNA) profiling using 48 plasma cfDNA samples from patients with advanced cancer. Results: Using this approach, we identified therapeutically relevant focal CNAs in 13 of 48 (27%) cfDNA samples from patients with metastatic cancer, including 11 of 36 (31%) from patients with mCRPC. We further show that PRINCe is effective at whole genome coverages as low as 0.005x. Combining PRINCe with targeted multiplexed-PCR NGS of the same cfDNA enables mutation and CNA assessment using effective coverage as low as 25x based on calibrating sequencing depth to cfDNA tumor content. Lastly, PRINCe identifies pre-treatment cfDNA copy number profiles that can be used for inexpensive disease monitoring. Conclusions: Taken together, our screening approach enables broadly applicable cfDNA based precision oncology for patients with advanced cancer through rapid, inexpensive identification of therapeutically relevant CNAs and pre-treatment genomic profiles for disease monitoring, while also guiding additional cfDNA profiling approaches to reserve costly ultra-deep approaches for patients with very low cfDNA tumor content.

Ethnicity-specific pharmacogenetics: the case of warfarin in African Americans

Using a derivation cohort (N=349), we developed the first warfarin dosing algorithm that includes recently discovered polymorphisms in VKORC1 and CYP2C9 associated with warfarin dose requirement in African Americans (AAs). We tested our novel algorithm in an independent cohort of 129 AAs and compared the dose prediction to the International Warfarin Pharmacogenetics Consortium (IWPC) dosing algorithms. Our algorithm explains more of the phenotypic variation (R(2)=0.27) than the IWPC pharmacogenomics (R(2)=0.15) or clinical (R(2)=0.16) algorithms. Among high-dose patients, our algorithm predicted a higher proportion of patients within 20% of stable warfarin dose (45% vs 29% and 2% in the IWPC pharmacogenomics and clinical algorithms, respectively). In contrast to our novel algorithm, a significant inverse correlation between predicted dose and percent West African ancestry was observed for the IWPC pharmacogenomics algorithm among patients requiring ⩾60 mg per week (β=-2.04, P=0.02).

Plasma glycoprotein profiling for colorectal cancer biomarker identification by lectin glycoarray and lectin blot

Colorectal cancer (CRC) remains a major worldwide cause of cancer-related morbidity and mortality largely due to the insidious onset of the disease. The current clinical procedures utilized for disease diagnosis are invasive, unpleasant, and inconvenient; hence, the need for simple blood tests that could be used for the early detection of CRC. In this work, we have developed methods for glycoproteomics analysis to identify plasma markers with utility to assist in the detection of colorectal cancer (CRC). Following immunodepletion of the most abundant plasma proteins, the plasma N -linked glycoproteins were enriched using lectin affinity chromatography and subsequently further separated by nonporous silica reversed-phase (NPS-RP)-HPLC. Individual RP-HPLC fractions were printed on nitrocellulose coated slides which were then probed with lectins to determine glycan patterns in plasma samples from 9 normal, 5 adenoma, and 6 colorectal cancer patients. Statistical tools, including principal component analysis, hierarchical clustering, and Z-statistics analysis, were employed to identify distinctive glycosylation patterns. Patients diagnosed with colorectal cancer or adenomas were shown to have dramatically higher levels of sialylation and fucosylation as compared to normal controls. Plasma glycoproteins with aberrant glycosylation were identified by nano-LC-MS/MS, while a lectin blotting methodology was used to validate proteins with significantly altered glycosylation as a function of cancer progression. The potential markers identified in this study for diagnosis to distinguish colorectal cancer from adenoma and normal include elevated sialylation and fucosylation in complement C3, histidine-rich glycoprotein, and kininogen-1. These potential markers of colorectal cancer were subsequently validated by lectin blotting in an independent set of plasma samples obtained from 10 CRC patients, 10 patients with adenomas, and 10 normal subjects. These results demonstrate the utility of this strategy for the identification of N -linked glycan patterns as potential markers of CRC in human plasma, and may have the utility to distinguish different disease states.

I131-tositumomab monotherapy as frontline treatment for follicular lymphoma: Updated results after a median follow-up of 8 years

8033

Background: Monoclonal antibody-based therapies are improving the outcome for patients (pts) with follicular lymphoma (FL). Radioimmunotherapy has been found to be effective for pts with relapsed/refractory disease, but even more so when used as frontline treatment. Methods and Results. We previously reported the results of a phase II, single-institution, study of anti-CD20 I-131- Tositumomab (Bexxar) given as a single agent and as a single one-week treatment for 76 pts with Stage 3 or 4 FL (NEJM 352:441, 2005). An overall response (OR) rate and complete remission (CR) rate of 95% and 75%, respectively, were observed. With a median follow-up of 5.1 yrs, 5-yr overall survival (OS) and progression-free survival (PFS) were 89% and 59%, respectively, with a median PFS reached at 6.1 yrs. We now report on this pt cohort after a median follow-up of 7.93 yrs. The 8-year and 10-yr OS is estimated (by KM) now at 86% and 8-yr PFS is 50% (95% CI: 38.8 - 61.7%). Only 3 additional relapses have occurred in the additional follow-up period (at 8.0, 8.3, and 9.2 years) in those with CRs. The 8-yr PFS for the 57 pts who achieved CR is now 64%. The median for PFS has now being reached for CRs at 9.2 yrs. When the impact of baseline FLIPI scores were analyzed, only 8-yr OS was significantly affected when low-risk (LR) and intermediate-risk (IR) categories were combined and compared to the high-risk (HR) category (92% vs. 75%; p = 0.029). The 8-yr PFS for LR + IR pts was 56% vs. 35% for HR pts (p = 0.317). 27 of the 76 total pts (35%) had HR scores. Of additional importance, no cases of MDS or AML have yet been observed. Other longterm toxicities including thyroid status and second non-hematologic cancers will be updated at the meeting. Conclusions. These data underscore the high degree of effectiveness and durability of remissions achieved with a single, one-week course of frontline Bexxar and should serve as a benchmark for comparison to other studies using more prolonged and toxic treatments, including those combining unlabeled or radiolabeled antibodies with chemotherapy.

No significant financial relationships to disclose.

Stimulation of intestinal mucosal afferent nerves increases superior mesenteric artery and decreases mesenteric adipose tissue blood flow

We tested the hypothesis that stimulation of intestinal mucosal afferent nerves produces an increase in superior mesenteric artery (SMA) but a decrease in mesenteric adipose tissue (MAT) blood flow. In anesthetized rats, blood flow in the SMA (pulsed Doppler flowmetry) and MAT (hydrogen gas clearance) was measured simultaneously before and after administration of 0.9% saline, 640 microM capsaicin, or 5% dextrose into the intestinal lumen. The changes in the SMA were 3.8 +/- 3.0, 15.9 +/- 4.0, and 18.8 +/- 7.6%; and those in the MAT, 4.7 +/- 4.0, -11.5 +/- 3.4, and -0.07 +/- 3.4% of baseline, respectively. The data indicate that exposure of the intestinal lumen to an afferent nerve stimulant or nutrient induced a dichotomous pattern of blood flow changes, an increase in the SMA and a reduction in MAT. The capsaicin-sensitive afferent nerves may be instrumental in mediating these energy responses.

Radioimmunotherapy with iodine (131)I tositumomab for relapsed or refractory B-cell non-Hodgkin lymphoma: updated results and long-term follow-up of the University of Michigan experience

CD20-targeted radioimmunotherapy is a promising new treatment for B-cell non-Hodgkin lymphoma (NHL). We now provide updated and long-term data on 59 chemotherapy-relapsed/refractory patients treated with iodine (131)I tositumomab in a phase I/II single-center study. Fifty-three patients received individualized therapeutic doses, delivering a specified total-body radiation dose (TBD) based on the clearance rate of a preceding dosimetric dose. Six patients received dosimetric doses only. Dose-escalations of TBD were conducted separately in patients who had or had not undergone a prior autologous stem cell transplant (ASCT) until a nonmyeloablative maximally tolerated TBD was established (non-ASCT = 75 cGy, post-ASCT = 45 cGy). Fourteen additional non-ASCT patients were treated with 75 cGy. Unlabeled antibody was given prior to labeled dosimetric and therapeutic doses to improve biodistribution. Forty-two (71%) of 59 patients responded; 20 (34%) had complete responses (CR). Thirty-five (83%) of 42 with low-grade or transformed NHL responded versus 7 (41%) of 17 with de novo intermediate-grade NHL (P =.005). For all 42 responders, the median progression-free survival was 12 months, 20.3 for those with CR. Seven patients remain in CR 3 to 5.7 years. Sixteen patients were re-treated after progression; 9 responded and 5 had a CR. Reversible hematologic toxicity was dose limiting. Only 10 patients (17%) had human anti-mouse antibodies detected. Long-term, 5 patients developed elevated thyroid-stimulating hormone levels, 5 were diagnosed with myelodysplasia and 3 with solid tumors. A single, well-tolerated treatment with iodine (131)I tositumomab can, therefore, produce frequent and durable responses in NHL, especially low-grade or transformed NHL. (Blood. 2000;96:1259-1266)

Sublingual glyceryl trinitrate for uterine relaxation at Caeserean section--a prospective trial

We report a prospective study on the use of sublingual glyceryl trinitrate at Caesarean section to induce uterine relaxation; 23 women were entered into the study with both emergency and elective cases considered. A metered dose spray was used to deliver a dose of 400 or 800 microgrammes of glyceryl trinitrate to the women. There were no major side-effects of hypotension or postpartum haemorrhage. The mean maximal systolic blood pressure drop in the patients following drug administration was 18% of the systolic pressure prior to drug administration. Subjective assessment of uterine tone showed the uterus to contract well postdelivery in response to standard oxytocic regimens. Minimal maternal side-effects were reported. We conclude that glyceryl trinitrate is a safe form of uterine relaxation at Caesarean section which may be used in emergency situations and may also be given prophylactically in cases such as breech presentation and in delivery of the preterm infant where fetal trauma is possible. The use of a metered-dose sublingual spray is ideally suited to obstetric practice, being both easy to use and also rapidly administered.

Iodine-131-anti-B1 radioimmunotherapy for B-cell lymphoma

PURPOSE

The CD20 B-lymphocyte surface antigen expressed by B-cell lymphomas is an attractive target for radioimmunotherapy, treatment using radiolabeled antibodies. We conducted a phase I dose-escalation trial to assess the toxicity, tumor targeting, and efficacy of nonmyeloablative doses of an anti-CD20 monoclonal antibody (anti-B1) labeled with iodine-131 (131I) in 34 patients with B-cell lymphoma who had failed chemotherapy.

PATIENTS AND METHODS

Patients were first given tracelabeled doses of 131I-labeled anti-B1 (15 to 20 mg, 5 mCi) to assess radiolabeled antibody biodistribution, and then a radioimmunotherapeutic dose (15 to 20 mg) labeled with a quantity of 131I that would deliver a specified centigray dose of whole-body radiation predicted by the tracer dose. Whole-body radiation doses were escalated from 25 to 85 cGy in sequential groups of patients in 10-cGy increments. To evaluate if radiolabeled antibody biodistribution could be optimized, initial patients were given one or two additional tracer doses on successive weeks, each dose preceded by an infusion of 135 mg of unlabeled anti-B1 one week and 685 mg the next. The unlabeled antibody dose resulting in the most optimal tracer biodistribution was also given before the radioimmunotherapeutic dose. Later patients were given a single tracer dose and radioimmunotherapeutic dose preceded by infusion of 685 mg of unlabeled anti-B1.

RESULTS

Treatment was well tolerated. Hematologic toxicity was dose-limiting, and 75 cGy was established as the maximally tolerated whole-body radiation dose. Twenty-eight patients received radioimmunotherapeutic doses of 34 to 161 mCi, resulting in complete remission in 14 patients and a partial response in eight. All 13 patients with low-grade lymphoma responded, and 10 achieved a complete remission. Six of eight patients with transformed lymphoma responded. Thirteen of 19 patients whose disease was resistant to their last course of chemotherapy and all patients with chemotherapy-sensitive disease responded. The median duration of complete remission exceeds 16.5 months. Six patients remain in complete remission 16 to 31 months after treatment.

CONCLUSION

Nonmyeloablative radioimmunotherapy with 131I-anti-B1 is associated with a high rate of durable remissions in patients with B-cell lymphoma refractory to chemotherapy.

Hormonal mechanisms in blood pressure reduction during hemodialysis in patients with chronic renal failure

To elucidate the hormonal mechanisms of blood pressure (BP) reduction during hemodialysis in patients with chronic renal failure (CRF), we performed this study using 7 normotensive (NT) and 17 hypertensive (HT) patients who were strictly matched in age, body weight, body weight gain from the last HD, and duration of HD. Blood pressure, pulse rate, plasma norepinephrine (NE), and plasma dopamine levels were used as indices of sympathetic nerve activity, before, at 50% of hemodialysis (HD) and at 100% of HD (at the end of HD) on the third day after the last HD. As hemodialytic BP reduction was defined as BP decline of more than 10% in pre-HD mean BP, in normotensive patients with CRF, hemodialytic BP reduction was recognized in 0/7 (0%) at 50% of HD and 4/7 (57%) at 100% of HD, and in hypertensive patients it was recognized in 3/17 (18%) at 50% of HD and 4/17 (24%) at 100% of HD. Percentile changes in plasma NE levels increased slightly following hemodialysis in normotensive patients with hemodialytic BP reduction and in hypertensives without BP reduction, while those in normotensives without BP reduction and in hypertensives with BP reduction did not change. However, percentage changes in plasma dopamine (DA) levels decreased significantly at the end of HD (NT; p < 0.05, HT; p < 0.01) following hemodialysis in both normotensive and hypertensive patients with hemodialytic BP reduction, while changes in patients without BP reduction, percentage changes in DA did not change (patients with BP reduction vs. patients without BP reduction). In conclusion, hemodialytic BP reduction may be predisposed by abnormal sympathetic nerve responsiveness.

Recognition of parts of famous-face photographs by children: an experimental note

Children aged between 5 and 10 years were shown photographs of familiar TV personalities, presenters, and celebrities for immediate recognition (naming). The pictures were of whole faces, outer features only (hair, chin, ears), or inner features (eyes, nose, mouth). Only the oldest group (9-10 years) resembled adults in recognising these familiar faces more efficiently from internal than external parts. In the youngest children (5-6 years) there were some indications that the outer face features were more salient, particularly when cartoon characters were included in the array.

Treatment of non-insulin-dependent diabetes mellitus and its complications. A state of the art review

Non-insulin-dependent diabetes mellitus (NIDDM) is a major health problem which occurs predominantly in the older population; 16.8% of persons over age 65 years have NIDDM. The total health costs of NIDDM are in excess of $US20 billion annually. The primary objective in the treatment of NIDDM is to achieve normoglycaemia, without aggravating coexisting abnormalities. Common abnormalities include obesity, hypertension, retinopathy, nephropathy and neuropathies. Diet, and consequent bodyweight reduction, is the cornerstone of therapy for NIDDM. Total calorie intake should be limited, while the percentage of calories from carbohydrates should be increased and that from fats and cholesterol should be decreased. Exercise may also help to reduce bodyweight. Sulphonylurea drugs stimulate insulin secretion from beta-cells, and may be a useful adjunct to nonpharmacological therapy. Failure to respond to sulphonylurea drugs may be primary (25 to 30% of initially treated patients) or secondary (5 to 10% per year). It is not clear which is the most effective pharmacological intervention in such cases. Options include switching to or combining therapy with insulin, a biguanide, or other insulin-sparing antihyperglycaemic agents, e.g. alpha-glucosidase inhibitors, thiazolidinediones, chloroquine or hydroxychloroquine, or fibric acid derivatives such as clofibrate. Other experimental agents include the fatty acid oxidation inhibitors and dichloroacetate. Specific agents, such as antihypertensives, lipid lowering agents and sorbitol inhibitors, may be needed to prevent the complications arising from the spectrum of clinical and metabolic abnormalities which arise from insulin resistance.

Potential role of 12 hydroxyeicosatetraenoic acid in angiotensin II-induced calcium signal in rat glomerulosa cells

Recent evidence suggests that 12 hydroxyeicosatetraenoic acid (12HETE), a product of the 12 lipoxygenase (LO) pathway of arachidonic acid metabolism, may have a role in mediating angiotensin II (AII)-induced aldosterone secretion. The present study examined the possible role of the 12 LO product 12HETE in AII-induced calcium ([Ca++]i) signals in rat glomerulosa cells. The addition of 12HETE to glomerulosa cells induced a dose-dependent (10(-6)-10(-8) M) rise in [Ca++]i levels that was sustained over 15 min. The effects of 12HETE on [Ca++]i were attenuated but not blocked by nifedipine (5 x 10(-6) M) and were preserved in a calcium-free medium, suggesting mobilization of intracellular calcium stores. Furthermore, the 12HETE-mediated rise in [Ca++]i was almost entirely abolished by dantrolene. In parallel, 12HETE reversed the inhibitory effect of nifedipine on AII-induced aldosterone secretion [AII (10(-9) M) - 36 +/- 7, AII + nifedipine (5 x 10(-6) M) - 13 +/- 2, AII + nifedipine + 12HETE (5 x 10(-8) M) - 27 +/- 4 ng/10(6) cells]. Dantrolene also inhibited AII-dependent aldosterone secretion (AII 10(-9) M - 75.8 +/- 5.6, AII + dantrolene 10(-6) M 45.5 +/- 8.8 ng/10(-6) cells), but this inhibition could not be reversed by 12HETE 10(-8) M (45.4 +/- 10.6 ng/10(6) cells). The LO blockers baicalein and BW755C inhibited the effect of AII on aldosterone production and on [Ca++]i in a parallel fashion. During LO blockade, the addition of 12HETE (10(-7) M) restored the AII-induced rise in [Ca++]i. Collectively, these observations suggest that activation of the LO pathway in the rat adrenal glomerulosa contributes to change in cytosolic calcium, which may be important for the steroidogenic effect of AII.

Long-term effects of the angiotensin converting enzyme inhibitor captopril on metabolic control in non-insulin-dependent diabetes mellitus

The role of angiotensin converting enzyme (ACE) inhibitors in improving insulin-mediated glucose uptake has been described. However, their effects on long-term glucose control in diabetes mellitus are less well established. This study examines the effect of 4 months of captopril treatment on blood pressure (BP) and glucose control in 130 subjects with non-insulin-dependent diabetes mellitus (NIDDM) and hypertension. Therapy for glycemic control was adjusted during a 3 month period prior to entry into active BP treatment and was not changed during 4 months of captopril administration. Fasting blood glucose and sitting BP were measured before and at 1, 2, 3, and 4 months of captopril monotherapy. Hemoglobin (Hb) A1c, serum electrolytes, creatinine, total cholesterol, and triglycerides were measured before and at 4 months. There were significant reductions in fasting blood glucose from baseline at 1 month (P < .01) and further stepwise decreases in values at 2, 3, and 4 months. Differences in glucose from month to month were highly significant. HbA1c was stable over a 3-month pretrial period, then decreased (P < .001) from baseline at 4 months of active treatment. Mean serum potassium increased from 4.4 to 4.7 (P < .001) at month 4 and there was an inverse correlation (r = -0.2, P < .025) between changes in potassium and HbA1c. Total serum cholesterol fell (P < .01) at month 4 of treatment. Serum creatinine and blood urea were unchanged, but of 18 patients with mild proteinuria pretrial, 12 of 18 were negative for protein at 4 months.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro effects of insulin on aldosterone production in rat zona glomerulosa cells

Though long standing diabetes mellitus is frequently accompanied by hypoaldosteronism, the role of insulin in this setting has never been clearly established. In the present study we have examined the direct effects of insulin on aldosterone production in rat zona glomerulosa cells in vitro. Insulin is shown to directly stimulate aldosterone production in a dose dependent manner, and to attenuate angiotensin II mediated aldosterone production, without affecting angiotensin II receptor binding kinetics. Insulin had no effect on aldosterone production mediated by the other physiological stimuli (K+ and ACTH). These data suggest a possible interaction between insulin and angiotensin II in the regulation of aldosterone secretion.

Glucose, insulin, and insulin resistance as biochemical predictors of hypertension

Obesity, essential hypertension, and diabetes mellitus share certain metabolic disturbances. The predictive value of disordered glucose metabolism and insulin action for hypertension are discussed. Several studies have examined the relationship between hypertension and glucose metabolism in diverse populations, and tend to indicate a predictive role for insulin and glucose metabolism disturbances in the development of hypertension.

Parathyroid hormone, platelet calcium, and blood pressure in normotensive subjects

Relations between platelet cytosolic calcium, parathyroid hormone, and blood pressure were investigated in 91 normotensive subjects: 47 men and 44 women ranging in age from 24 to 70 years. The men had higher mean arterial blood pressure, serum creatinine, and body mass index than the women. Serum total calcium, plasma ionized calcium, and parathyroid hormone (measured as both intact hormone and mid-molecule fragment) were not different between men and women; however, serum phosphate was higher in women than in men. Basal platelet cytosolic calcium was higher in men than in women (113.7 +/- 1.9 versus 105.9 +/- 1.7, respectively; p less than 0.01), but there was no difference in the peak platelet cytosolic calcium responses to thrombin between the two groups. In the combined group of male and female subjects, platelet cytosolic calcium correlated with diastolic blood pressure and mean arterial pressure (r = 0.37, p less than 0.001 and r = 0.32, p less than 0.01, respectively). Intact parathyroid hormone correlated with systolic and mean arterial blood pressure (r = 0.41, p less than 0.001 for both). Age correlated with both systolic blood pressure (r = 0.40, p less than 0.001) and intact parathyroid hormone (r = 0.51, p less than 0.001). When multiple regression analysis was performed using mean arterial pressure as the dependent variable, platelet cytosolic calcium and intact parathyroid hormone maintained significant correlations with mean arterial pressure. Platelet cytosolic calcium did not correlate with intact parathyroid hormone. These results suggest that both platelet cytosolic calcium and intact parathyroid hormone are associated with blood pressure regulation in normotensive subjects. However, the influences of these two factors on blood pressure are not interrelated.

The differential efficacy of antihypertensive agents in the elderly

A number of controlled trials have shown that antihypertensive therapy is beneficial to the elderly (greater than or equal to 60 years of age). Even so, there may be deleterious age-related effects associated with such therapy. Because of physiological and pathophysiological problems peculiar to the elderly (many of which remain to be defined precisely), both benefits and untoward effects of antihypertensive drugs differ, sometimes within classes of agents themselves. None of the traditional agents is ideal for the management of hypertension in the elderly. Differential efficacy and tolerability of various antihypertensive agents has often been claimed but none of these claims appears established beyond dispute. Increasing evidence, however, suggests that the serotonin antagonist ketanserin may be more effective and better tolerated in elderly hypertensives. If the elderly are to derive maximum benefit from antihypertensive therapy, the question of age-related differential effects of agents used needs to be addressed in carefully designed studies to determine the nature and magnitude of such effects, where they exist and what clinical implications they may have.

Salt-sensitive blood pressure and exaggerated vascular reactivity in the hypertension of diabetes mellitus

PURPOSE

This study evaluates the effects of dietary salt restriction and loading on blood pressure in normotensive and hypertensive patients with non-insulin-dependent diabetes mellitus (NIDDM). Salt sensitivity of blood pressure responses is compared to vascular reactivity to infused angiotensin II on the two sodium diets.

PATIENTS AND METHODS

We studied 19 patients with NIDDM (seven normotensive, 12 hypertensive) and seven nondiabetic control subjects under metabolic balance after 6 days on a constant low- (20 mEq) sodium diet and again after 6 days on a high- (250 mEq) sodium diet. Salt sensitivity of blood pressure was determined by the increment in integrated 24-hour blood pressure values on changing from the low- to the high-sodium diet. Blood pressure and plasma aldosterone responses to a graded-dose infusion of angiotensin II were also examined on both sodium diets.

RESULTS

Eight of 12 hypertensive patients with NIDDM displayed salt-sensitive blood pressure responses, whereas none of the normotensive patients with NIDDM or control subjects were salt-sensitive. Patients with NIDDM also had augmented blood pressure responses to infused angiotensin II on both sodium diets when compared to control subjects. Whereas controls had reduced vascular responses to angiotensin II on the low-sodium diet, these responses were not decreased in patients with NIDDM. Patients with NIDDM also retained more sodium on the high-sodium diet than did the control subjects.

CONCLUSION

Hypertension in patients with NIDDM is frequently salt-sensitive, which may be due to sodium retention and enhanced vascular reactivity to angiotensin II. Since sodium restriction does not normally reduce vascular reactivity to angiotensin II in NIDDM, salt-restricted diets may be less effective in blood pressure control in hypertensive NIDDM.

Captopril improves hypertension and cardiomyopathy in rats with pheochromocytoma

Hypertension and cardiomyopathy are prominent findings in humans and rats harboring pheochromocytomas, tumors that can secrete enormous quantities of catecholamines. We have previously found that alpha- and beta-adrenergic receptor antagonists may ameliorate the hypertension and cardiomyopathy found in New England Deaconess Hospital rats implanted with pheochromocytoma. The present studies were designed to determine the possible action of the angiotensin converting enzyme inhibitor captopril on these changes in rats harboring pheochromocytomas. Rats were implanted with transplantable pheochromocytomas and treated with captopril dissolved in the drinking water (1 mg/ml) for 4-6 weeks. Systolic blood pressure was monitored by using the tail-cuff technique. In the rats with pheochromocytoma, blood pressure progressively increased to 184 +/- 3 mm Hg after the tumor was implanted. However, in rats with pheochromocytoma treated with captopril in the drinking water before the development of hypertension, blood pressure did not increase (137 +/- 3 mm Hg). In rats with pheochromocytoma with established hypertension, captopril normalized the systolic blood pressure. Plasma norepinephrine was markedly elevated to a similar extent in both groups compared with unimplanted control rats. Plasma renin activities were slightly lower in rats with pheochromocytoma compared with unimplanted control rats. Treatment with captopril of rats with pheochromocytoma did not modify contraction of isolated rings of thoracic aorta exposed in vitro to either phenylephrine or angiotensin II. Treatment with captopril markedly attenuated the cardiomyopathy induced by pheochromocytoma. These results demonstrate that captopril prevents the development of hypertension despite markedly elevated concentrations of catecholamines. In addition, captopril attenuates catecholamine-induced cardiomyopathy in pheochromocytoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibitory action of norepinephrine on sodium transport in vascular smooth muscle cells in culture

Cultured vascular smooth muscle cells from porcine aortas incubated in Na+ -free medium rapidly release their intracellular Na+ contents (Nai) (23 +/- 4% of baseline after 60 min incubation, mean +/- SEM of 18 experiments). Total Nai release was inhibited by 35-40% after addition of ouabain and by 60-70% after addition of ouabain + bumetanide. Norepinephrine inhibited ouabain and bumetanide-sensitives Na+ efflux with an IC50 of about 10(-9)-10(-8) M. Addition of the alpha-adrenergic agonist phenylephrine (10 microM) to the cells mimicked the inhibitory action of norepinephrine on Nai release. Conversely, the beta-adrenergic agonist isoproterenol was without effect on Nai release. Simultaneous addition of 10 microM norepinephrine and the alpha-adrenergic antagonist phentolamine prevented any effect of norepinephrine on the rate of Nai decline. In A-10 cultured vascular smooth muscle cells, the alpha-adrenergic agonist phenylephrine (10 microM) inhibited 40.0 +/- 8.1% of ouabain-sensitive Rb+ influx and 70.7 +/- 6.9% of bumetanide-sensitive Rb+ influx (mean +/- SEM of three experiments). 50% inhibition of bumetanide-sensitive Rb+ influx was obtained with about 5 x 10(-7) M of phenylephrine. Our results show that in vascular smooth muscle cells a [Na+, K+, Cl-]-cotransport system is able to catalyze outward Na+ movements (in Na+ -free media) of a similar order of magnitude to those of the Na+, K+ pump and that alpha-adrenergic stimulation markedly inhibits Na+ efflux (and Rb+ influx) through these two transport systems.

Renin regulation in type II diabetes mellitus: influence of dietary sodium

Numerous abnormalities in the renin-angiotensin system have been described in diabetes mellitus. Plasma renin activity (PRA) has been noted to be low, normal, and high in diabetic patients; these variable results may be explained by differences in patient selection and standardization of study conditions. We evaluated PRA and inactive renin responses in Type II normotensive (n = 7) and hypertensive (n = 12) diabetic patients specifically selected for no or minimal evidence (background retinopathy) for microvascular complications. Patients were studied in a metabolic ward after 7 days on a constant low sodium (20 meq/day) and 7 days on a high sodium (250 meq/day) diet. Nondiabetic control subjects (n = 7) were evaluated under similar conditions. On low sodium intake, mean PRA levels were significantly reduced in the hypertensive diabetic group, but were not different between the control and normotensive diabetic groups. Hypertensive diabetic patients on high sodium intake also had greater reductions in PRA responses compared with the other study groups. In general, diabetic subjects on high sodium intake excreted less sodium and had more cumulative sodium retention than control subjects. Levels of inactive renin were not significantly different between the normotensive and hypertensive diabetic patients and were comparable with the levels in control subjects. Inactive renin levels changed in a similar direction and magnitude as PRA in response to sodium intake and posture in the three study groups. Infusion of angiotensin II led to comparable reductions in PRA in both diabetic groups and in the control group, suggesting an intact short feedback loop control.(ABSTRACT TRUNCATED AT 250 WORDS)

Site-specificity of histone H1 methylation by two H1-specific protein-lysine N-methyltransferases from Euglena gracilis

1. The histone H1 fractions from rat spleen and liver were used as substrates for two H1-specific protein-lysine N-methyltransferases, V-A and V-B (protein methylase III) from Euglena gracilis. 2. When the enzymatically [methyl-3H]labeled H1 fractions were resolved by two-dimensional gel electrophoresis, four subtypes were found to be methylated (H1b, H1c, H1d and H1e). Both enzymes methylated H1c and H1b to approximately the same extent; H1d and H1e were methylated preferentially by enzyme V-B and V-A, respectively. 3. Histone H1c, [methyl-3H]labeled by the methyltransferase V-A, which had been digested by arginine-specific protease (Arg C protease), showed a single radioactive peptide on HPLC, indicating methylation site specificity of the enzyme. 4. Arg C protease-digestion of [methyl-3H]labeled H1c labeled by methyltransferase V-B indicated that this enzyme methylated two sites on the histone molecule. 5. The histone H1c methylation sites of these two enzymes did not overlap, indicating the two enzymes have different site specificity. 6. In combination with the other results, this suggests that the two enzymes serve discrete purposes, possibly involving the presumed different actions of histone H1 subtypes.

Treatment of hypertensive diabetic patients

This article briefly reviews the literature on the incidence of hypertension in the diabetic population, the risks associated with this combination of conditions, and the nonpharmacologic and other therapies available to lower blood pressure in these patients. Although several studies of nonpharmacologic therapies and diuretics are considered, the emphasis is on the reported advantages and disadvantages of beta-blockers, centrally acting agents, alpha-adrenergic-blocking agents, calcium-channel blockers, and angiotensin-converting enzyme inhibitors.

Management of hypertension in the patient with diabetes mellitus. Focus on the use of angiotensin-converting enzyme inhibitors

Hypertension in patients with diabetes mellitus increases the risk of both macrovascular and microvascular complications. Such microvascular complications as diabetic nephropathy and retinopathy are accelerated in the presence of arterial hypertension. Evidence suggests that the complications of diabetes mellitus begin early in the course of the disorder as manifested by microalbuminuria and increased vascular reactivity. These findings are accompanied by changes in the renin-angiotensin-aldosterone system including reductions in plasma renin activity. These changes could be secondary to volume expansion that may be a direct consequence of elevated blood glucose, suggesting that the metabolic disorder in diabetes contributes to the etiology of hypertension in these patients. Adequate treatment of hypertension is crucial to the prevention of complications; however, many antihypertensive agents have limited usefulness in diabetes mainly because of their unfavorable side effects. Diuretics lower blood pressure in hypertensive diabetics, but their metabolic effects are especially undesirable in this population. beta-Blockers alter glucose and lipid metabolism in diabetic patients and reduce regional blood flow. Central acting agents and alpha-blockers are often associated with orthostatic hypotension, sexual dysfunction, and central nervous system side effects. Angiotensin-converting enzyme inhibitors (ACEIs) such as captopril effectively lower blood pressure in diabetic patients and have few unwanted effects. They may improve metabolic control and have favorable effects on glucose metabolism. The ACEIs also produce improved regional hemodynamics which may lead to the improvement in or prevention of the progression of diabetic nephropathy.

Enzymatic methylation of in vitro synthesized apocytochrome c enhances its transport into mitochondria

The gene for iso-1-cytochrome c from Saccharomyces cerevisiae was recloned into a pSP65 vector containing an active bacteriophage SP promoter. The iso-1-cytochrome c gene was cloned as an 856-base pair XhoI-HindIII fragment. When the resulting plasmid was digested at the HindIII site 279 bases downstream from the termination codon of the gene and transcribed in vitro using SP6 RNA polymerase, full length transcripts were produced. The SP6 iso-1-cytochrome c mRNA was translated using a rabbit reticulocyte lysate system, and the protein products were analyzed on sodium dodecyl sulfate-polyacrylamide gels. One major band with a molecular weight of 12,000 was detected by autofluorography and coincided with the Coomassie staining band of apocytochrome c from S. cerevisiae. The product was also shown to be identical with that of standard yeast apocytochrome c on an isoelectrofocusing gel. The in vitro synthesized iso-1-apocytochrome c was enzymatically methylated by adding partially purified S-adenosyl-L-methionine:cytochrome c-lysine N-methyltransferase (protein methylase III, EC 2.1.1.59) from S. cerevisiae along with S-adenosyl-L-methionine to the in vitro translation mixtures. The methylation was shown to be inhibited by the addition of the methylase inhibitor S-adenosyl-L-homocysteine or the protein synthesis inhibitor puromycin. The principal type of methylated amino acid in the protein was found to be epsilon-N-trimethyllysine which accounted for 77% of the total. Finally, the methylation of in vitro synthesized iso-1-apocytochrome c was found to increase its import into mitochondria isolated from S. cerevisiae 2-4-fold over unmethylated protein, but not into rat liver mitochondria. This suggests that methylation facilitates the import of apocytochrome c into mitochondria by a specific receptor mechanism.

Mechanisms of hypertension in obesity

We conclude that the following may explain the rise in blood pressure with obesity and the subsequent fall in blood pressure (Fig. 2): (1) An increase in calories, protein, or carbohydrate leads to an increase in plasma catecholamines, sympathetic nervous system activity, and insulin secretion. (2) These factors, in turn, lead to increased renal sodium retention and stimulation of the renin-aldosterone system which, in turn, leads to: (3) An increased cardiac output with an inability to appropriately adjust the peripheral resistance to maintain normotension with resultant hypertension. Conversely, the fall in blood pressure with weight reduction can be explained by (Fig. 3): (1) A decrease in calorie, carbohydrate, or protein intake which leads to: (2) A decrease in circulating plasma catecholamines, sympathetic nervous system activity, and insulin secretion which results in: (3) A natriuresis and decrease in the renin-aldosterone system, which causes a decrease in circulating blood volume and in cardiac output. This, in turn, lowers blood pressure towards normal. The unanswered question still remains: why do some obese patients become hypertensive and others remain normotensive? Perhaps there are weight-sensitive individuals and weight-resistant individuals just as there appear to be salt-sensitive and salt-resistant hypertensive patients. Perhaps the answer is genetic. These questions also remain to be answered.

Dopaminergic binding and inhibitory effect in the bovine adrenal zona glomerulosa

Dopaminergic mechanisms may be involved in the regulation of aldosterone secretion in humans and in the rat. Whether these effects are indirect or are exerted directly at the adrenal level has not yet been resolved. We now report the identification of dopaminergic binding sites in the bovine adrenal zone glomerulosa using [3H]spiperone, a butyrophenone with high affinity for D2 dopamine receptors. Specific [3H]spiperone binding (defined as binding displaceable by 10 microns (+)-butaclamol) reached equilibrium within 20 minutes at 22 degrees C, was reversible, and was heat labile (60 degrees C). Binding was of high affinity and saturable with a Kd of 1.8 +/- 0.2 nM and maximal specific binding of 38 +/- 8 fmol/mg (means +/- SEM; n = 18). [3H]Spiperone binding was unaffected by coincubation with angiotensin II, adrenocorticotropic hormone, or KCl. Binding characteristics, including a dissociation constant at the nanomolar range, greater potency of the D2-agonist LY 171555 relative to the D1-agonist SKF 38393 in inhibiting [3H]spiperone binding, and lack of stimulation of cyclic adenosine 3',5'-monophosphate by dopamine (10(-4) M), were consistent with a predominantly D2-receptor. In vitro studies with collagenase-dispersed adrenal zona glomerulosa cells showed that dopamine (10(-4) M) attenuated angiotensin II-stimulated aldosterone secretion. These observations are consistent with a direct inhibitory effect of dopamine on aldosterone secretion in the adrenal zona glomerulosa.

Myelin basic protein-specific protein methylase I activity in shiverer mutant mouse brain

Myelin basic protein (MBP)-specific protein-arginine N-methyltransferase (protein methylase I) activity in homozygous shiverer (shi/shi) mutant mouse brain is significantly higher than in the normal littermate brain at the onset of myelination. While the enzyme activity (expressed as pmol of S-adenosyl-L-[methyl-14C]methionine used/min/mg enzyme protein) increases coincidently during the period of myelination in the normal brain (15-18 days of age), it decreases significantly in the mutant brain during this period of time. These results are in contrast to those found with another dysmyelinating mutant, jimpy (jp/Y) mice, in which the enzyme activity in the mutant brains is similar to that in the normal animals but remains unchanged during the myelination process. There is no difference in the weight and protein concentration of the normal and shiverer mutant brains with corresponding ages, and the histone-specific protein methylase I activity is also unaffected in the shiverer brain.