Hyperinsulinism and hyperammonemia in infants with regulatory mutations of the glutamate dehydrogenase gene

BACKGROUND

A new form of congenital hyperinsulinism characterized by hypoglycemia and hyperammonemia was described recently. We hypothesized that this syndrome of hyperinsulinism and hyperammonemia was caused by excessive activity of glutamate dehydrogenase, which oxidizes glutamate to alpha-ketoglutarate and which is a potential regulator of insulin secretion in pancreatic beta cells and of ureagenesis in the liver.

METHODS

We measured glutamate dehydrogenase activity in lymphoblasts from eight unrelated children with the hyperinsulinism-hyperammonemia syndrome: six with sporadic cases and two with familial cases. We identified mutations in the glutamate dehydrogenase gene by sequencing glutamate dehydrogenase complementary DNA prepared from lymphoblast messenger RNA. Site-directed mutagenesis was used to express the mutations in COS-7 cells.

RESULTS

The sensitivity of glutamate dehydrogenase to inhibition by guanosine 5'-triphosphate was a quarter of the normal level in the patients with sporadic hyperinsulinism-hyperammonemia syndrome and half the normal level in patients with familial cases and their affected relatives, findings consistent with overactivity of the enzyme. These differences in enzyme insensitivity correlated with differences in the severity of hypoglycemia in the two groups. All eight children were heterozygous for the wild-type allele and had a mutation in the proposed allosteric domain of the enzyme. Four different mutations were identified in the six patients with sporadic cases; the two patients with familial cases shared a fifth mutation. In two clones of COS-7 cells transfected with the mutant sequence from one patient, the sensitivity of the enzyme to guanosine 5'-triphosphate was reduced, findings similar to those in the child's lymphoblasts.

CONCLUSIONS

The hyperinsulinism-hyperammonemia syndrome is caused by mutations in the glutamate dehydrogenase gene that impair the control of enzyme activity.

A systematic meta-review of predictors of antidepressant treatment outcome in major depressive disorder

INTRODUCTION

The heterogeneity of symptoms and complex etiology of depression pose a significant challenge to the personalization of treatment. Meanwhile, the current application of generic treatment approaches to patients with vastly differing biological and clinical profiles is far from optimal. Here, we conduct a meta-review to identify predictors of response to antidepressant therapy in order to select robust input features for machine learning models of treatment response. These machine learning models will allow us to learn associations between patient features and treatment response which have predictive value at the individual patient level; this learning can be optimized by selecting high-quality input features for the model. While current research is difficult to directly apply to the clinic, machine learning models built using knowledge gleaned from current research may become useful clinical tools.

METHODS

The EMBASE and MEDLINE/PubMed online databases were searched from January 1996 to August 2017, using a combination of MeSH terms and keywords to identify relevant literature reviews. We identified a total of 1909 articles, wherein 199 articles met our inclusion criteria.

RESULTS

An array of genetic, immune, endocrine, neuroimaging, sociodemographic, and symptom-based predictors of treatment response were extracted, varying widely in clinical utility.

LIMITATIONS

Due to heterogeneous sample sizes, effect sizes, publication biases, and methodological disparities across reviews, we could not accurately assess the strength and directionality of every predictor.

CONCLUSION

Notwithstanding our cautious interpretation of the results, we have identified a multitude of predictors that can be used to formulate a priori hypotheses regarding the input features for a computational model. We highlight the importance of large-scale research initiatives and clinically accessible biomarkers, as well as the need for replication studies of current findings. In addition, we provide recommendations for future improvement and standardization of research efforts in this field.

Is 95% pancreatectomy the procedure of choice for treatment of persistent hyperinsulinemic hypoglycemia of the neonate?

A 95% pancreatectomy became the treatment of choice for persistent hyperinsulinemic hypoglycemia of the neonate (PHHN, Nesidioblastosis) at the author's institution, when lesser resections failed to prevent hypoglycemia in 25% to 50% of cases. With few outcome data available in the literature, the authors reviewed their 25-year experience to assess the efficacy and the long-term consequences of this procedure. Since 1971, 27 infants underwent a 95% pancreatectomy for the treatment of PHHN. None had responded to medical treatment (glucose infusion, glucagon, octreotide, diazoxide), and two had 85% pancreatectomy that failed. The procedure consisted of resecting the pancreas including the uncinate process, leaving only the gland lying between the common bile duct (CBD) and the duodenum and a small rim of pancreas along the duodenal sweep. Hyperinsulinemia and hypoglycemia recurred in nine children (33%), all within 2 to 5 days. Seven of them were subsequently cured with near-total pancreatic resection. Partial pancreatic regrowth was evident at reoperation. In two cases hypoglycemia was controlled with diazoxide and frequent feedings because reoperation was refused. The gross anatomic findings and the histopathology were not predictive of treatment failure. Perioperative complications occurred in four of 27 children (15%) after 95% pancreatectomy and in four of seven children (57%) after near-total pancreatectomy. Clinical follow-up ranged from 0.5 to 18 years (mean, 8 years; median, 8 years). To date, diabetes has developed in 15 children (56%), nine of 20 (45%) after 95% pancreatectomy (mean age, 9.7 years) and six of seven (86%) after a near-total pancreatectomy (mean age, 1.7 years). After 95% pancreatectomy, the incidence of diabetes increased with age, developing in nine of the 13 (69%) children followed up for more than 4 years. The failure of 95% pancreatectomy to prevent hypoglycemia in one third of children with PHHN and the ultimate development of diabetes in a minimum of two-thirds, indicates that an alternative treatment strategy is needed for this disease.

Angiotensin converting enzyme inhibitor therapy to decrease microalbuminuria in normotensive children with insulin-dependent diabetes mellitus

It has been proposed that lowering glomerular pressure in children with insulin-dependent diabetes mellitus will reduce microalbuminuria and that this reduction may preserve renal function. We therefore conducted a double-blind, placebo-controlled, crossover trial to compare 3 months of treatment with the angiotensin converting enzyme inhibitor captopril (0.9 mg/kg/day), and 3 months of placebo administration to 12 normotensive adolescents with insulin-dependent diabetes mellitus, 11 with microalbuminuria (albumin excretion rate of 15 to 200 micrograms/min) and one with early overt nephropathy. Mean age (+/- SD) was 14.4 +/- 1.7 years, and disease duration was 5.1 +/- 2.5 years. Albumin excretion rate decreased significantly during captopril therapy (baseline 78 +/- 114 micrograms/min; mean of monthly measurements 38 +/- 55 micrograms/min vs placebo 78 +/- 140 micrograms/min; p less than 0.001). During captopril therapy, albumin excretion was reduced by 41 +/- 44% and decreased in 10 of 12 subjects, but was unchanged in two, one with a borderline albumin excretion rate (16.3 micrograms/min) and one with diabetes of short duration (2.9 years). Plasma renin activity rose significantly during captopril therapy, and mean arterial pressure decreased slightly (placebo 81 +/- 7 mm Hg; captopril 76 +/- 5 mm Hg; p = 0.004). After 3 months of captopril treatment, glomerular filtration rate and renal plasma flow did not change significantly. Hemoglobin Alc values remained stable during the study. The only side effect of captopril was diarrhea in one patient. We conclude that, in the short term, captopril is effective in decreasing albumin excretion rate in normotensive children with insulin-dependent diabetes mellitus and microalbuminuria, without significant side effects. Longer trials are indicated in an attempt to delay or prevent overt nephropathy.

Transcriptomic and clonal characterization of T cells in the human central nervous system

T cells provide critical immune surveillance to the central nervous system (CNS), and the cerebrospinal fluid (CSF) is thought to be a main route for their entry. Further characterization of the state of T cells in the CSF in healthy individuals is important for understanding how T cells provide protective immune surveillance without damaging the delicate environment of the CNS and providing tissue-specific context for understanding immune dysfunction in neuroinflammatory disease. Here, we have profiled T cells in the CSF of healthy human donors and have identified signatures related to cytotoxic capacity and tissue adaptation that are further exemplified in clonally expanded CSF T cells. By comparing profiles of clonally expanded T cells obtained from the CSF of patients with multiple sclerosis (MS) and healthy donors, we report that clonally expanded T cells from the CSF of patients with MS have heightened expression of genes related to T cell activation and cytotoxicity.

Severe hypoglycemia in children with insulin-dependent diabetes mellitus: frequency and predisposing factors

We surveyed 311 children with insulin-dependent diabetes mellitus to evaluate the frequency and characteristics of those children experiencing severe hypoglycemia (defined by an episode of coma, convulsion, or both). The children and their parents completed a questionnaire, and we reviewed the hospital records to confirm reported episodes. Ninety-seven (31%) reported severe hypoglycemia, and a further 50 (16%) reported moderate hypoglycemia requiring the assistance of another person but not resulting in coma or convulsion. In 164 children (53%) there was no history of either moderate or severe hypoglycemia. Sixty-nine (22%) reported the occurrence of more than one severe hypoglycemic episode (range 2 to 20); 52 (16%) reported such an event in a single year. A total of 285 episodes were reported, 39% during sleep and 61% while awake. Children reporting such events tended to have diabetes of longer duration and be younger at the time of the first episode. Hemoglobin A1c concentration at the time closest to the severe episode was significantly lower than in children reporting no hypoglycemia. All families had been taught to use glucagon to reverse severe hypoglycemia at home, but it was available in only 80 of the 97 homes and used in only 30. These data suggest that severe hypoglycemia is common in children with insulin-dependent diabetes mellitus who are treated conventionally. Greater vigilance and education are required both to prevent and to treat severe hypoglycemia in children with insulin-dependent diabetes mellitus.

24-homologated 1,25-dihydroxyvitamin D3 compounds: separation of calcium and cell differentiation activities

A series of 24-homologated 1,25-dihydroxyvitamin D3 compounds have been chemically synthesized and studied with regard to their activity in inducing differentiation of human promyelocyte HL-60 cells to monocytes and in calcium mobilizing activity in vitamin D deficient rats. Homologation of 1,25-dihydroxyvitamin D3 or its delta 22 analogue by one or two carbons increases by 10-fold and three-carbon homologation reduces by half the activity in causing differentiation of HL-60. On the other hand, homologation causes a substantial decrease in in vivo calcium mobilization activity. The addition of each carbon at the 24-position decreases binding to the HL-60 receptor or rat intestinal receptor by 5-10-fold so that binding affinity of the trihomo compound for the receptors is 130 times less that of 1,25-dihydroxyvitamin D3. Thus, binding affinity for the receptor cannot account for the preferential activity of the 24-homologated compounds in inducing cell differentiation.

Insulin lispro lowers postprandial glucose in prepubertal children with diabetes

OBJECTIVE

This study compared the glucose-lowering effect of insulin lispro, given before or after meals, with regular human insulin given before meals in prepubertal children with diabetes.

RESEARCH DESIGN AND METHODS

A 3-way crossover, open-label study involving 61 prepubertal children (ages 2.9-11.4 years) with type 1 diabetes. The children were randomly assigned to receive regular human insulin 30 to 45 minutes before meals, insulin lispro within 15 minutes before or immediately after meals, combined with basal insulin. Each treatment lasted 3 months. Hemoglobin A(1c) levels and home glucose monitoring profiles were measured at the end of each treatment period.

RESULTS

Treatment with insulin lispro before breakfast resulted in lower 2-hour postprandial glucose values than regular human insulin (11.7 +/- 4.4 mmol/L vs 15.0 +/- 5.4 mmol/L). Similarly, insulin lispro given before dinner resulted in lower blood glucose values 2 hours postprandially (8.8 +/- 5.0 mmol/L vs 10.8 +/- 5.4 mmol/L) than regular human insulin. When insulin lispro was administered after meals, the 2-hour glucose levels were between those seen with either insulin lispro or regular human insulin given before meals. The number and types of adverse events, the rates of hypoglycemia, and the HbA(1c) levels did not differ among the 3 therapies.

CONCLUSIONS

In prepubertal children, insulin lispro given before meals is safe and significantly lowers postprandial glucose levels after breakfast and dinner compared with regular human insulin, and insulin lispro given after the meal provides similar benefits as regular human insulin before the meal.

Iron deposition in the anterior pituitary in homozygous beta-thalassemia: MRI evaluation and correlation with gonadal function

OBJECTIVE

Iron deposition in the anterior pituitary continues to pose a serious problem in older patients with homozygous beta-thalassemia particularly in terms of gonadal function. This study aimed to investigate whether iron loading within the pituitary correlated with endocrine function.

PATIENTS

33 patients above 15 years of age, with transfusion-dependent homozygous beta-thalassemia and iron overload were studied. All had been receiving deferoxamine since 1978.

DESIGN AND MEASUREMENTS

The endocrine status of the patients was assessed on clinical examination by an endocrinologist, and by a gonadotropin releasing hormone stimulation test. MRI of the pituitary was carried out for each patient.

RESULTS

Anterior pituitary function (GnRH stimulation test) correlated well with MRI results. However, no correlation was found between the MRI measurements, the GnRH stimulation test and the clinical status of the patients, as 28 out of the 33 patients achieved normal puberty.

CONCLUSIONS

MRI in conjunction with a GnRH stimulation test may be useful in predicting future impairment of pituitary function; however, further studies are needed to assess the effect of chelation therapy on the iron overload in the gland.

Developmental trajectory of oligodendrocyte progenitor cells in the human brain revealed by single cell RNA sequencing

Characterizing the developmental trajectory of oligodendrocyte progenitor cells (OPC) is of great interest given the importance of these cells in the remyelination process. However, studies of human OPC development remain limited by the availability of whole cell samples and material that encompasses a wide age range, including time of peak myelination. In this study, we apply single cell RNA sequencing to viable whole cells across the age span and link transcriptomic signatures of oligodendrocyte-lineage cells with stage-specific functional properties. Cells were isolated from surgical tissue samples of second-trimester fetal, 2-year-old pediatric, 13-year-old adolescent, and adult donors by mechanical and enzymatic digestion, followed by percoll gradient centrifugation. Gene expression was analyzed using droplet-based RNA sequencing (10X Chromium). Louvain clustering analysis identified three distinct cellular subpopulations based on 5,613 genes, comprised of an early OPC (e-OPC) group, a late OPC group (l-OPC), and a mature OL (MOL) group. Gene ontology terms enriched for e-OPCs included cell cycle and development, for l-OPCs included extracellular matrix and cell adhesion, and for MOLs included myelination and cytoskeleton. The e-OPCs were mostly confined to the premyelinating fetal group, and the l-OPCs were most highly represented in the pediatric age group, corresponding to the peak age of myelination. Cells expressing a signature characteristic of l-OPCs were identified in the adult brain in situ using RNAScope. These findings highlight the transcriptomic variability in OL-lineage cells before, during, and after peak myelination and contribute to identifying novel pathways required to achieve remyelination.

Relationship of etiology to treatment in congenital hypothyroidism

We examined the patterns of TSH, T(4), and treatment schedules from diagnosis to 4 yr of age in 125 children (50 males anf 75 females) with congenital hypothyroidism (CH). Subjects were divided into 3 groups based on their thyroid scans: 1) athyreosis (n = 31), 2) dysgenesis (n = 54; 49 lingual and 5 hypoplastic), and 3) dyshormonogenesis (n = 40). Follow-up evaluation was carried out at 2-4 wk and 3, 6, 9, 12, 24, 36, and 48 months of age. Median gestational age, age at onset of therapy, and starting L-T(4) dose were similar in the three groups. In infants with athyreosis median screening TSH levels were higher (P < 0.02) and confirmatory T(4) levels were lower than in the other two groups (P < 0.01 vs. dysgenetic; P < 0.05 vs. dyshormonogenetic CH). During the first 6 months of therapy, mean TSH levels were highest in the athyrotic group, intermediate in the dysgenetic group, and lowest in the dyshormonogenetic group. In children with athyreosis, TSH levels normalized by 12 months of age. At 12 months dysgenetic patients had the highest TSH levels (P < 0.05). During the entire study period, TSH levels were lowest in patients with dyshormonogenesis (except at 48 months) and normalized earlier. Mean T(4) levels normalized by 2-4 weeks in all groups. At 3 and 6 months, the percentage of patients who required dose changes was highest in the athyrotic group, and at 12 months it was highest in the dysgenetic group. The athyrotic group received the highest dose of L-T(4), and dyshormonogenetic group received the lowest dose. We conclude that treatment and follow-up schedules for CH may differ in the three etiological categories based on the different hormonal patterns and responses to therapy. Children with athyreosis need close monitoring particularly early in life, whereas those with dysgenesis and dyshormonogenesis require more attention later in life.

The effect of abnormal intrauterine thyroid hormone economies on infant cognitive abilities

OBJECTIVE

To evaluate how intrauterine and neonatal thyroid hormone deficiencies affect infant cognitive abilities.

METHOD

26 infants with intrauterine or neonatal thyroid hormone deficiency and 20 full-term infants with normal thyroid economies were studied at 6 months of age or corrected age. Reasons for thyroid hormone deficiency were maternal hypothyroidism, maternal hyperthyroidism treated with antithyroid medication, congenital hypothyroidism, and low-risk prematurity. A computer-generated task during which infants' eye-movements were videotaped was used to assess attention, memory, and learning abilities

RESULTS

Data from transcribed videotapes showed the study group was significantly less attentive and had longer reaction times than controls but did not differ on indices of sustaining attention or learning. Within thyroid-deficient groups, offspring of treated hyperthyroid mothers showed an atypical profile suggestive of hypervigilance.

CONCLUSION

A decreased fetal or maternal thyroid hormone supply in pregnancy is associated with infants' poorer attention and altered rates of information processing.

Circulating alanine production and disposal in healthy subjects

Circulating-alanine production and disposal rates were estimated in eight healthy postabsorptive subjects by means of U-14C alanine and U-14C glucose infusions. The mean circulating-alanine production rate was 368 +/- S.E.M. 28 mumol/min. -1.8(2). Approximately 50 percent of circulating-alanine carbon exchanged rapidly with that of circulating lactate. Approximately 30 per cent of circulating alanine exchanged with protein stores. Other disposal was 29 +/- 2 per cent to circulating glucose and 40 +/- 4 per cent to oxidation.

CONCLUSIONS

(1) The carbon moieties of circulating alanine and lactate are freely exchangeable. (2) Assessment of the contribution of alanine to gluconeogenesis will depend on establishing the extent to which the precursor pyruvate carbon is derived from glycolysis or from proteolysis. (3) If the principal pyruvate precursor is glycolysis, then the principal specific function of the glucose-alanine cycle appears to be ammonia transport.

Child abuse associates with increased recruitment of perineuronal nets in the ventromedial prefrontal cortex: a possible implication of oligodendrocyte progenitor cells

Child abuse (CA) is a strong predictor of psychopathologies and suicide, altering normal trajectories of brain development in areas closely linked to emotional responses such as the prefrontal cortex (PFC). Yet, the cellular underpinnings of these enduring effects are unclear. Childhood and adolescence are marked by the protracted formation of perineuronal nets (PNNs), which orchestrate the closure of developmental windows of cortical plasticity by regulating the functional integration of parvalbumin interneurons into neuronal circuits. Using well-characterized post-mortem brain samples, we show that a history of CA is specifically associated with increased densities and morphological complexity of WFL-labeled PNNs in the ventromedial PFC (BA11/12), possibly suggesting increased recruitment and maturation of PNNs. Through single-nucleus sequencing and fluorescent in situ hybridization, we found that the expression of canonical components of PNNs is enriched in oligodendrocyte progenitor cells (OPCs), and that they are upregulated in CA victims. These correlational findings suggest that early-life adversity may lead to persistent patterns of maladaptive behaviors by reducing the neuroplasticity of cortical circuits through the enhancement of developmental OPC-mediated PNN formation.

Hypoglycemia associated with clonidine testing for growth hormone deficiency

We have observed 4 cases of hypoglycemia associated with clonidine stimulation of growth hormone secretion; only one patient had growth hormone deficiency. Significant drowsiness after administration of clonidine may prolong the period of fasting in these children and mask early signs and symptoms, leading to severe hypoglycemia.

Nonaggregating insulin solutions for long-term glucose control in experimental and human diabetes

A physiologic additive for dissolving insulin crystals for parenteral application has been found. Insulin crystals are relatively insoluble in simple aqueous solutions. They will dissolve, however, in highly acidic solutions, but these are not suitable for parenteral use. Both neutral and acid pH insulin solutions have a tendency for the dissolved hormone to reaggregate. Notwithstanding possible changes in biologic activity, such formed aggregates must be prevented because they interfere with the flow in portable insulin delivery devices and result in the loss of glycemic control. The addition of 1.5% autologous serum to the aqueous diluent for insulin has eliminated these difficulties and increased by 37% the apparent biologic activity of insulin solutions prepared in this way. With this additive, continuous uninterrupted intravenous insulin infusion has provided near ideal blood glucose control in four pancreatectomized dogs for 5 mo and four patients with juvenile-onset diabetes for 18--23 days. Serum apparently contains factor(s) that promote the dissolution of insulin and prevent the formation of peptide aggregates in dilute solutions.

Waveform requirements for metabolic normalization with continuous intravenous insulin delivery in man

Devices and methods for long-term intravenous (i.v.) insulin infusion in ambulatory patients have recently been developed. However, to date optimal waveforms for open-loop insulin administration in severely insulin deficient patients have not been defined.

We studied 7 nonobese uncomplicated type 1 diabetics aged 16.5 ± 0.2 yr who received insulin continuously for 14–23 days by central venous infusion. A pattern of i.v. insulin administration was developed and eventually refined to include a constant basal infusion rate augmented at meal time by a series of 3 pulses. The first pulse lasted 10–15 min with an infusion rate 1.5–2 times the basal rate. The second pulse was 60–100 min in duration with a rate 4–6 times the basal infusion rate. The third pulse lasted 40–100 min with an infusion rate 1.5–3 times the basal rate. Accompanying the evolution of this waveform, the mean fasting plasma glucose fell from 262 ± 40 mg/dl on conventional therapy to 92 ± 9 mg/dl during infusion with normal meal excusions (mean a.c. glucose 80 ± 3 mg/dl with a rise of 35 ± 3 mg/dl at 41 ± 3 min). Mean urinary glucose excretion decreased from 55 before to 1.9 g/day during the infusion period. Fasting serum cholesterol and triglycerides dropped from 220 ± 28 and 281 ± 94 to 138 ± 13 and 115 ± 24 mg/dl, respectively.Mean HbA, declined from 14.8% before to 10.7% at the conclusion of the infusion period. All indices of control showed improvement significant at P &lt; 0.05. There were no catheter-related complications and the system was well accepted by all subjects.

These studies confirm that continuous central venous insulin infusion with a relatively simple waveform is feasible for the prolonged normalization of glycemia and other indices of metabolic control in ambulatory adolescent diabetics.

Analysis of Features Selected by a Deep Learning Model for Differential Treatment Selection in Depression

Background: Deep learning has utility in predicting differential antidepressant treatment response among patients with major depressive disorder, yet there remains a paucity of research describing how to interpret deep learning models in a clinically or etiologically meaningful way. In this paper, we describe methods for analyzing deep learning models of clinical and demographic psychiatric data, using our recent work on a deep learning model of STAR*D and CO-MED remission prediction.

Methods: Our deep learning analysis with STAR*D and CO-MED yielded four models that predicted response to the four treatments used across the two datasets. Here, we use classical statistics and simple data representations to improve interpretability of the features output by our deep learning model and provide finer grained understanding of their clinical and etiological significance. Specifically, we use representations derived from our model to yield features predicting both treatment non-response and differential treatment response to four standard antidepressants, and use linear regression and t-tests to address questions about the contribution of trauma, education, and somatic symptoms to our models.

Results: Traditional statistics were able to probe the input features of our deep learning models, reproducing results from previous research, while providing novel insights into depression causes and treatments. We found that specific features were predictive of treatment response, and were able to break these down by treatment and non-response categories; that specific trauma indices were differentially predictive of baseline depression severity; that somatic symptoms were significantly different between males and females, and that education and low income proved important psycho-social stressors associated with depression.

Conclusion: Traditional statistics can augment interpretation of deep learning models. Such interpretation can lend us new hypotheses about depression and contribute to building causal models of etiology and prognosis. We discuss dataset-specific effects and ideal clinical samples for machine learning analysis aimed at improving tools to assist in optimizing treatment.

New devices and methods for long-term vascular access for blood sampling and insulin infusion

Studies aimed at quantifying the benefits of infused rather than injected insulin have been impeded by the unavailability of suitable methods for continuous vascular access. We have developed indwelling catheters suitable for the long-term blood sampling as well as insulin infusion. A typical catheter consists of a silicone rubber tube, which terminates with a blunt-point needle. Internal or external reinforcement as well as a removable strain relief fitting protect the area of insertion of the needle. Anchoring of the implanted extravascular portion of the catheter is important and is achieved by special grommets that prevent motion without obstructing the lumen. Methods of catheter assembly as well as implantation in the jugular and portal veins of dogs and jugular veins of humans are described. A total of 34 blood sampling catheters were implanted in 26 beagle dogs: 74% were uncomplicated with a duration of implantation of 18–576 days while 15% and 11%, respectively, failed due to infection or physical damage after an average of 200 days. Thirteen portal infusion catheters were implanted: 62% were functional a mean of 100 days (14–166 days) after implantation while 35% became covered with an endothelial sleeve and had to be removed. Thirty-two peripheral infusion catheters were implanted in dogs: one infection occurred, two catheters were physically damaged, and three were plugged. There were no catheter-related complications in the five adolescent diabetic subjects with such jugular venous catheters studied for an average of 19.5 days and three adult diabetic subjects in whom catheters remained patent for 150–270 days. It is the inherent characteristics of the silicone rubber material as well as the new methods of catheter construction and implantation that virtually eliminate catheter-related problems and that now provide an ideal route of access for long-term intravascular insulin infusion in diabetes mellitus.

Self-monitoring of blood glucose: how accurate are children with diabetes at reading chemstrip bG?

Accuracy of self-monitoring of blood glucose (SMBG) using Chemstrip bG (Bio-Dynamics, Indianapolis, Indiana) was studied in 90 randomly selected children with insulin-dependent diabetes mellitus (IDDM). For 28 children (mean age 8.3 +/- 3.6 yr) a parent routinely read the Chemstrip at home. The remaining 62 children (mean age 13.7 +/- 2.8 yr) read the Chemstrip themselves. Each child or parent analyzed 20 capillary blood samples using Chemstrips and answered a questionnaire on SMBG. The accuracy of SMBG of the group was high (mean correlation coefficient = 0.89 +/- 0.05), but consistency of measurement was variable (mean standard deviation = 1.90 +/- 0.57) and there was a general tendency to underread Chemstrips (mean y-intercept = 1.05 +/- 1.48; mean slope = 0.80 +/- 0.17). For each subject, 0-65% (mean of 34%) of readings were within 10% of the laboratory measurement, and 17-100% (mean 68%) within 20%. These results indicate that most subjects were fairly accurate in reading Chemstrips; however, analysis of accuracy is useful in identifying individuals who are inaccurate or inconsistent in SMBG. Continuing supervision of SMBG is necessary in children with IDDM.

Cell type specific transcriptomic differences in depression show similar patterns between males and females but implicate distinct cell types and genes

Major depressive disorder (MDD) is a common, heterogenous, and potentially serious psychiatric illness. Diverse brain cell types have been implicated in MDD etiology. Significant sexual differences exist in MDD clinical presentation and outcome, and recent evidence suggests different molecular bases for male and female MDD. We evaluated over 160,000 nuclei from 71 female and male donors, leveraging new and pre-existing single-nucleus RNA-sequencing data from the dorsolateral prefrontal cortex. Cell type specific transcriptome-wide threshold-free MDD-associated gene expression patterns were similar between the sexes, but significant differentially expressed genes (DEGs) diverged. Among 7 broad cell types and 41 clusters evaluated, microglia and parvalbumin interneurons contributed the most DEGs in females, while deep layer excitatory neurons, astrocytes, and oligodendrocyte precursors were the major contributors in males. Further, the Mic1 cluster with 38% of female DEGs and the ExN10_L46 cluster with 53% of male DEGs, stood out in the meta-analysis of both sexes.

Using a simulation centre to evaluate preliminary acceptability and impact of an artificial intelligence-powered clinical decision support system for depression treatment on the physician-patient interaction

BACKGROUND

Recently, artificial intelligence-powered devices have been put forward as potentially powerful tools for the improvement of mental healthcare. An important question is how these devices impact the physician-patient interaction.

AIMS

Aifred is an artificial intelligence-powered clinical decision support system (CDSS) for the treatment of major depression. Here, we explore the use of a simulation centre environment in evaluating the usability of Aifred, particularly its impact on the physician-patient interaction.

METHOD

Twenty psychiatry and family medicine attending staff and residents were recruited to complete a 2.5-h study at a clinical interaction simulation centre with standardised patients. Each physician had the option of using the CDSS to inform their treatment choice in three 10-min clinical scenarios with standardised patients portraying mild, moderate and severe episodes of major depression. Feasibility and acceptability data were collected through self-report questionnaires, scenario observations, interviews and standardised patient feedback.

RESULTS

All 20 participants completed the study. Initial results indicate that the tool was acceptable to clinicians and feasible for use during clinical encounters. Clinicians indicated a willingness to use the tool in real clinical practice, a significant degree of trust in the system's predictions to assist with treatment selection, and reported that the tool helped increase patient understanding of and trust in treatment. The simulation environment allowed for the evaluation of the tool's impact on the physician-patient interaction.

CONCLUSIONS

The simulation centre allowed for direct observations of clinician use and impact of the tool on the clinician-patient interaction before clinical studies. It may therefore offer a useful and important environment in the early testing of new technological tools. The present results will inform further tool development and clinician training materials.

Sustained normoglycemia in newly diagnosed type I diabetic subjects. Short-term effects and one-year follow-up

The impact on remission of normalizing blood glucose levels immediately after diagnosis of type I diabetes was studied in 14 adolescents. Accordingly, in this randomized prospective primary intervention study, 7 of the subjects (i.v. group) received insulin by continuous intravenous (i.v.) infusion via a portable preprogrammed system for 28-62 days and 7 (s.c. group) received conventional subcutaneous (s.c.) therapy. Before therapy, the two groups did not differ significantly with respect to glycosylated hemoglobin, fasting plasma C-peptide, or 24-h urinary C-peptide excretion. During the infusion period, the overall mean fasting plasma glucose (FPG) concentration for the i.v. group was 84 mg/dl with a mean coefficient of variation of 18 +/- 4% (mean +/- SD). During the comparable period for the s.c. group, the mean FPG was 253 mg/dl with a coefficient of variation of 30 +/- 20%. Twenty-four-hour urinary glucose excretions for the two groups were 0.29 +/- 0.06 (mean +/- SEM) and 59 +/- 11 g/day, respectively. Daily insulin requirements in the i.v. group decreased from 1.47 +/- 0.19 U/kg body wt/day at the start to 0.47 +/- 0.10 U/kg/day at the end of the infusion period. Notably, 10-25 days after the infusion period, 5 of 7 subjects experienced a further decrease to a low of 0.27 +/- 0.01 U/kg/day. The mean peak and low requirements in the s.c. group were 0.71 +/- 0.15 and 0.33 +/- 0.13 U/kg/day, respectively, with the only peak requirements being significantly different (P less than 0.01). No patient was able to discontinue insulin therapy.(ABSTRACT TRUNCATED AT 250 WORDS)