Analysis and applications of respiratory surface EMG: report of a round table meeting.

Surface electromyography (sEMG) can be used to measure the electrical activity of the respiratory muscles. The possible applications of sEMG span from patients suffering from acute respiratory failure to patients receiving chronic home mechanical ventilation, to evaluate muscle function, titrate ventilatory support and guide treatment. However, sEMG is mainly used as a monitoring tool for research and its use in clinical practice is still limited-in part due to a lack of standardization and transparent reporting. During this round table meeting, recommendations on data acquisition, processing, interpretation, and potential clinical applications of respiratory sEMG were discussed. This paper informs the clinical researcher interested in respiratory muscle monitoring about the current state of the art on sEMG, knowledge gaps and potential future applications for patients with respiratory failure.

Word-level intelligibility after caudal zona incerta stimulation for Parkinson's disease.

OBJECTIVES: To investigate the effect of caudal zona incerta-deep brain stimulation (cZi-DBS) on word-level speech intelligibility in patients with Parkinson's disease, under both an optimal listening condition and a simulated more naturalistic listening condition. MATERIALS AND METHODS: Spoken single words were extracted from read samples collected from 10 bilaterally implanted patients with PD pre- and post-cZi-DBS. Intelligibility was assessed through a transcription task performed by 32 naive listeners under two listening conditions: (i) with low-amplitude conversational speech added as background and (ii) with no added background noise. The listeners' responses were scored in terms of agreement with the intended words. RESULTS: Post-operatively, the total intelligibility score was significantly lower when cZi stimulation was switched on compared with off, for both listening conditions (with and without added background noise). Intelligibility was also significantly lower on stimulation compared with preoperative recordings, but only when assessed in the listening condition without background noise. The listening condition with added background noise resulted in significantly lower intelligibility scores compared with the no added noise condition for all stimulation conditions. CONCLUSIONS: The results of this study indicate that cZi-DBS in patients with PD can be detrimental to word-level speech intelligibility.

Detection of acute coronary occlusion with a novel mobile electrocardiogram device: a pilot study.

Aims: Many portable electrocardiogram (ECG) devices have been developed to monitor patients at home, but the majority of these devices are single lead and only intended for rhythm disorders. We developed the miniECG, a smartphone-sized portable device with four dry electrodes capable of recording a high-quality multi-lead ECG by placing the device on the chest. The aim of our study was to investigate the ability of the miniECG to detect occlusive myocardial infarction (OMI) in patients with chest pain. Methods and results: Patients presenting with acute chest pain at the emergency department of the University Medical Center Utrecht or Meander Medical Center, between May 2021 and February 2022, were included in the study. The clinical 12-lead ECG and the miniECG before coronary intervention were recorded. The recordings were evaluated by cardiologists and compared the outcome of the coronary angiography, if performed. A total of 369 patients were measured with the miniECG, 46 of whom had OMI. The miniECG detected OMI with a sensitivity and specificity of 65 and 92%, compared with 83 and 90% for the 12-lead ECG. Sensitivity of the miniECG was similar for different culprit vessels. Conclusion: The miniECG can record a multi-lead ECG and rule-in ST-segment deviation in patients with occluded or near-occluded coronary arteries from different culprit vessels without many false alarms. Further research is required to add automated analysis to the recordings and to show feasibility to use the miniECG by patients at home.

Deep brain stimulation - effects on swallowing function in Parkinson's disease.

OBJECTIVE: In patients with Parkinson's disease (PD), deep brain stimulation of the subthalamic nucleus (STN DBS) is well recognized in improving limb function, but the outcome on swallowing function has rarely been studied. The aim of this work was to evaluate the effect of STN DBS on pharyngeal swallowing function in patients with PD using self-estimation and fiberoptic endoscopic evaluation of swallowing. METHODS: Eleven patients (aged 41-72, median 61 years) were evaluated preoperatively and at 6 and 12 months after STN DBS surgery. All patients were evaluated with self-estimation on a visual analogue scale, and eight of them with a fiberoptic endoscopic examination with a predefined swallowing protocol including Rosenbek's Penetration-Aspiration Scale, Secretion Severity Scale, preswallow spillage, pharyngeal residue, and pharyngeal clearance. RESULTS: The self-assessments of swallowing function revealed a subjective improvement with STN DBS stimulation, whereas the data from the swallowing protocol did not show any significant effect of the STN DBS treatment itself. The prevalence of aspiration was not affected by the surgery. CONCLUSIONS: The results show that swallowing function was not negatively affected by STN DBS and the risk of aspiration did not increase. Self-estimation of swallowing function showed a subjective improvement due to stimulation.

Dystrophic Myopathy of the Diaphragm with Recurrent Severe Respiratory Failure is Congenital Myasthenic Syndrome 11.

We here present the case of a patient with a congenital myasthenic syndrome (CMS) due to pathogenic variants in the RAPSN gene. During childhood he experienced recurrent episodes of respiratory failure during respiratory infections. This and other cases were reported as isolated dystrophy of the diaphragmatic musculature. In adulthood, whole exome sequencing revealed two heterozygous pathogenic variants in the RAPSN gene. This led to the revision of the diagnosis to rapsyn CMS11 (OMIM:616326, MONDO:0014588). EMG, muscle ultrasound and the revision of muscle biopsies taken in childhood support this diagnosis. After the revision of the diagnosis, treatment with pyridostigmine was started. This resulted in a reduction of fatigability and an improvement in functional abilities and quality of life.

Swallowing function in Parkinson's patients following Zona Incerta deep brain stimulation.

OBJECTIVE: The purpose of the present study was to examine whether there was a negative effect of caudal Zona Incerta deep brain stimulation (cZI DBS) on pharyngeal swallowing function in Parkinson's patients (PD). There are no former reports including swallowing and cZI DBS. METHODS: Eight patients (aged 49-71 years; median 62) were evaluated pre- and post-operatively, at 6 and 12 months after DBS surgery. Evaluation tools were fiberoptic endoscopic evaluation of swallowing examinations and patients' self-assessments of their swallowing function including a visual analog scale and quality-of-life-related questions. The swallowing protocol included Rosenbek's Penetration-Aspiration Scale, Secretion Severity Scale and parameters for preswallow spillage, pharyngeal residue, and pharyngeal clearance. RESULTS: There was no clear-cut effect of neurostimulation post-operatively at 6 and 12 months on any of the swallowing parameters except for the preswallow spillage that was slightly worsened in the stimulation on condition 12 months post-operatively. The answers to the self assessment questions did not vary significantly. CONCLUSIONS: The effect of the stimulation on the swallowing function varied among individuals, but the overall outcome was that cZI DBS did not seem to have a negative influence on swallowing function in the eight patients studied.

First Report of Xanthomonas arboricola pv. pruni in Ornamental Prunus laurocerasus in the Netherlands.

In 2008, Dutch ornamental plant growers observed a leaf spot of cherry laurel (Prunus laurocerasus) at a greater incidence (5 to 50%) than the usual sporadic level (<1%). For advice on disease control, ~5 to 10% of these growers contacted Dutch regulatory officials. In November and December 2008, six symptomatic samples from northern and southern parts of the Netherlands were submitted for diagnosis. Leaf spots were chlorotic, most had a necrotic brown center with a distinct margin, and the spots readily abscised, resulting in a "shot-hole" appearance. Leaf spots from the samples were surface sterilized (2 s in 70% vol/vol alcohol), blotted dry on tissue paper, chopped into pieces (1 to 2 mm in diameter), and incubated for 30 min in 10 mM phosphate-buffered saline (PBS) (1). A 20-µl aliquot of extract per sample was streaked by dilution plating on four plates of yeast peptone glucose agar medium (1), and the plates were incubated for 2 to 3 days at 28°C. Isolations from all six samples yielded Xanthomonas-like colonies. After purification, characterization of all six isolates revealed oxidative, nonfermentative metabolism of glucose by rod-shaped, gram-negative bacterial cells. All six isolates were identified as Xanthomonas arboricola pv. pruni based on biochemical tests (1), fatty acid analysis (4), and immunofluorescence (IF) using polyclonal antibodies (Plant Research International, the Netherlands). Pathogenicity was tested on potted peach plants (cvs. Peregrine and Vaes Oogst) and on detached leaves of P. laurocerasus (cv. Novita) (1). The six field isolates from 2008 were each inoculated (108 CFU/ml) onto four leaves per plant of each of two peach plants (replicates). As positive control treatments, two reference strains (ATCC 19312 and PD740) were each inoculated onto the same number of leaves and plants, and as a noninoculated negative control treatment, leaves of two peach plants were treated with sterile 10 mM PBS buffer (1). All leaves inoculated with the six field isolates and the two reference strains developed typical bacterial spot symptoms in 3 to 4 weeks. Negative control plants showed no symptoms. The detached leaf assay performed with the same treatments on each of two leaves (replicates) showed identical results. The bacterium was reisolated from leaf spots associated with each of the eight symptomatic treatments and identity of the reisolates was confirmed by IF. Additionally, genotypic variation of 35 Dutch isolates of X. arboricola pv. pruni was assessed by BOX-PCR assay with the BOX A1R primer set (3), and Gyrase B gene sequencing (2). Both methods revealed 100% homology among the 35 isolates, suggesting a single, recent introduction of X. arboricola pv. pruni into the Netherlands. In a 2009 survey to assess distribution of the disease in the Netherlands, X. arboricola pv. pruni was found in 41 fields. Infected hosts included P. laurocerasus cvs. Otto Luyken, Rotundifolia, Novita, Etna, Anbri, Herbergii, Mischeana, and Caucasia. X. arboricola pv. pruni is a quarantine organism in countries affiliated under the EPPO (European and Mediterranean Plant Protection Organization). Phytosanitary measures were taken to prevent movement of infested plants from nurseries where X. arboricola pv. pruni was detected. References: (1) Anonymous. EPPO Bull. 36:129, 2006. (2) N. Parkinson et al. Int. J. Syst. Evol. Microbiol. 59:264, 2009. (3) J. Versalovic et al. Methods Mol. Cell. Biol. 5:25, 1994. (4) S. A. Weller et al. EPPO Bull. 30:375, 2000.

'Rapid speed of response to ECT in bipolar depression: A chart review.

OBJECTIVE: To validate a faster speed of response to electroconvulsive therapy (ECT) for bipolar depression (BPD) compared to major depressive disorder (MDD) METHOD: Retrospective chart review on an ECT cohort in an academic hospital setting. Speed of response was defined by the number of ECT treatments needed for response or remission. RESULTS: Sixty-four depressed patients were included, of whom 53 (MDD: 40, BPD: 13) could be analyzed. The bipolar group responded faster with a mean difference of 3.3 fewer ECT treatments to meet response criteria (MDD 10.4 vs. BPD 7.1, p = 0.054). When using mixed effects regression models for the response/remitter group (n = 35), a faster response for the bipolar group (AIC 252.83 vs 258.55, χ2 = 11.72, p = 0.008) was shown. Other factors, such as psychotic features or comorbidity, did not influence the speed of response. CONCLUSION: This chart review of an ECT cohort in an naturalistic academic hospital setting shows an evident and clinically relevant faster speed of response in bipolar depression.

Clinical evaluation of a PHMB-impregnated biocellulose dressing on paediatric lacerations.

OBJECTIVE: To evaluate the clinical benefits, primarily tolerability and reduction in pain levels, associated with the use of a PHMB-impregnated biosynthetic cellulose dressing (Suprasorb X + PHMB) on paediatric heel lacerations. METHOD: These lacerations were caused when children, who were being transported on their parents' bicycles, got their heels trapped in the wheel spokes. Where these injuries just comprised skin contusion and laceration, treatment had previously comprised cleansing followed by application of conventional dressings and moist wound healing dressings. However, the high incidence of infection necessitated regular dressing changes, which caused parents and children stress and anxiety. This clinical evaluation assessed the benefits of a new treatment protocol, where the PHMB-impregnated biocellulose dressing was applied and left in situ until epithelialisation occurred. A cork splint was used for 3 days to prevent pes equinus and to let the ankle joint rest. Change in wound size (cm²), incidence of local infection, wound bed characteristics and pain levels (measured on a 0-10 paediatric pain scale) were assessed at 3-day intervals during the 14-day treatment period. Satisfaction with the dressing was also evaluated. RESULTS: Twenty children (mean age 5.6 years (± 1.33) were recruited into the study and included in the analysis. The mean baseline wound area was 8.60cm² (± 6.57). The mean time to complete wound closure was 12.95 days (± 7.69) with a mean total of 4.70 visits (± 1.56). The mean VAS pain score was 9.55 (± 0.69), compared with 0.15 (± 0.37) on day 14 (p<0.003). At the second visit (after 3 days) 17 of the 20 children were reported to be free of pain. No cases of local infection were noted. CONCLUSION: The dressing was found to be child and parent friendly. The evaluation also showed that it was well tolerated and achieved good healing outcome. It has now been incorporated into the clinic's treatment protocol for these wounds. CONFLICT OF INTEREST: None. The authors have no relevant financial interest in this article. All authors were involved in the critical revision of the manuscript for important intellectual content.

Tongue movements and teat compression during bottle feeding: A pilot study of a quantitative ultrasound approach.

Nutritive sucking is a complex process, essential to proper growth and development. The complexity of this oral sensorimotor activity includes movements of the tongue and jaw. Tongue movements during nutritive sucking can only be visualized with instrumented methods such as ultrasound. Until now, studies using ultrasound during nutritive sucking performed measurements on each individual ultrasound image frame, which was quite time-consuming. The aim of this pilot study was to automatically process ultrasound video recordings in healthy infants during bottle feeding to measure teat compression and tongue movements. Tongue movements and teat compression during bottle feeding were visualized and recorded using 2D dynamic ultrasound imaging. A custom-made semi-automated analysis-routine was developed. Teat compression was expressed as the median difference in teat diameter during the recording. Tongue movements were expressed as the displacement of the tongue along four evenly distributed image lines and the corresponding time-shifts between those lines. The recordings of 12 out of 14 participants were adequate for the analysis of tongue movements. Teat compression could be analysed in the recordings of 6 participants. The reliability of our analysis-routine was considered to be good, and the analysis-routine was more time-efficient than manual frame-by-frame analysis. This quantitative analysis-routine is a promising tool, that can be used efficiently and accurately in the future to collect normative data that can serve as reference values to distinguish normal from abnormal tongue movements in infants with feeding difficulties.

Bayesian rank-based hypothesis testing for the rank sum test, the signed rank test, and Spearman's ρ.

Bayesian inference for rank-order problems is frustrated by the absence of an explicit likelihood function. This hurdle can be overcome by assuming a latent normal representation that is consistent with the ordinal information in the data: the observed ranks are conceptualized as an impoverished reflection of an underlying continuous scale, and inference concerns the parameters that govern the latent representation. We apply this generic data-augmentation method to obtain Bayes factors for three popular rank-based tests: the rank sum test, the signed rank test, and Spearman's ρ s .

Insulin-like growth factors and insulin-like growth factor-binding proteins in relation to disease status and incidence of hypoglycaemia in patients with a gastrointestinal stromal tumour.

OBJECTIVE: Patients with a gastrointestinal stromal tumour (GIST) suffering from non-islet cell tumour-induced hypoglycaemia (NICTH), being associated with increased plasma levels of pro-insulin-like growth factor (IGF)-IIE[68-88], have been reported occasionally. We studied the clinical relevance of pro-IGF-IIE[68-88] and other IGF-related proteins in GIST patients. PATIENTS AND METHODS: Twenty-four patients were included. Plasma samples were collected before 1 week and median 5 months after start of treatment with imatinib, and levels of IGF-I, total IGF-II, pro-IGF-IIE[68-88], insulin-like growth factor-binding protein (IGFBP)-2, -3 and -6 were determined. GIST specimens from 17 patients and tumour cyst fluid from two patients were analysed for IGF-II and IGFBP-2. RESULTS: Before treatment and/or during follow-up, 3 of 24 (13%) patients showed increased plasma levels of pro-IGF-IIE[68-88]. All three developed NICTH. Overall, patients with metastatic disease, elevated serum lactate dehydrogenase activity or total tumour size >12 cm had the highest pro-IGF-IIE[68-88] levels. Most patients had increased plasma IGFBP-2 levels and these levels were significantly higher in patients with progressive disease. (Pro-)IGF-II was expressed in 82% of GISTs and IGFBP-2 only in one case. CONCLUSION: We identified pro-IGF-IIE[68-88] as a marker that may be used in the surveillance of GIST.

Sources and quantity of 3,5,3'-triiodothyronine in several tissues of the rat.

The local conversion of thyroxine (T4), which is an important source of intracellular 3,5,3'-triiodothyronine (T3) in several rat tissues, has been subject of recent investigations. In the present study the regulation of this phenomenon in vivo was investigated in various peripheral tissues of the rat. Intact euthyroid and radiothyroidectomized (Tx) rats received a continuous intravenous infusion of [125I]T4 and [131I]T3 until isotope equilibrium was attained. In addition to the labeled iodothyronines, Tx rats received a continuous intravenous infusion of 0.2 or 1.0 microgram carrier T4/100 g body wt per d, to create hypothyroid or slightly hypothyroid conditions, respectively. After the animals were bled and perfused the contribution of T3 derived from local conversion of T4 to T3 [Lc T3(T4)] to the total T3 in homogenates from several tissues and subcellular fractions from the liver, kidney, and anterior pituitary gland could be calculated. In all experiments T3 in muscle was derived exclusively from the plasma. In the cerebral cortex and cerebellum, however, most of the intracellular T3 was derived from the intracellular conversion of T4 to T3. It is demonstrated that for hypothyroid rats an increased relative contribution of Lc T3(T4) reduced the loss of total T3 in the brain. This phenomenon was also encountered for the anterior pituitary gland, although in this tissue the proportion of the total tissue T3, contributed by locally produced T3 was considerably lower than the values found for the cerebral cortex and cerebellum in all experiments. The present findings, regarding the source and quantity of pituitary nuclear T3 strongly suggest that both plasma T3 and T4 (through its local conversion into T3) play a role in the regulation of thyrotropin secretion. The contribution of Lc T3(T4) to the total pituitary nuclear T3 was of minor importance in euthyroid rats (approximately 20%), compared with that found for both groups in T4-supplemented athyreotic rats (approximately 40%). The total T3 concentration in the liver decreased from euthyroid to hypothyroid rats and was associated with a decrease in the tissue/plasma T3 concentration gradient. A minor proportion of hepatic T3 was contributed by Lc T3(T4), which in fact decreased significantly from the euthyroid to the hypothyroid state. In contrast to other subcellular fractions from the liver, no Lc T3(T4) could be demonstrated in the nuclear fraction. It is suggested that the liver plays an important role with respect to regulation of the circulating T3 concentration. In the kidney, a very small proportion of the total T3 was derived from locally produced T3 in all experiments (4-7%). As found in the liver, all nuclear T3 appeared to be derived from the plasma. In contrast to the liver, subcellular T3 pools in the kidney seemed to be exchangeable.

Sustained effects of recombinant GH replacement after 7 years of treatment in adults with GH deficiency.

CONTEXT: The goal of GH replacement with recombinant human GH (rhGH) is to ameliorate symptoms, signs, and complications of adult GH deficiency (GHD) in the long term. To determine whether the observed short-term beneficial effects of rhGH treatment are sustained in the long term, we evaluated biochemical and anthropometric parameters after 7 years of rhGH replacement. PATIENTS AND METHODS: After 2, 5, and 7 years of rhGH replacement, 63 adult GHD patients (30 men, 52 adult-onset GHD) were assessed. IGF-I increased during rhGH replacement, and a stable dose of rhGH was reached within 1 year of rhGH substitution. Thereafter, this individualized dose was continued. RESULTS: Plasma levels of total cholesterol and low-density lipoprotein cholesterol decreased even after 5 years of rhGH replacement (11% decrease, P < 0.001; 22% decrease, P < 0.001 respectively). High-density lipoprotein cholesterol levels increased during 7 years of rhGH replacement (1.4 +/- 0.5 mmol/l at baseline vs 1.7 +/- 0.5 mmol/l after 7 years, P < 0.001), whereas triglyceride concentrations remained unchanged. Fasting glucose levels increased during follow-up, mainly during the first 2 years of rhGH replacement (4.4 +/- 0.7 mmol/l to 5.0 +/- 1.0 mmol/l, P < 0.001). Body mass index increased during follow-up, whereas waist circumference and waist-to-hip ratio remained unchanged. Diastolic blood pressure decreased (P = 0.002), but when patients using antihypertensive medication were excluded this decrease did not reach significance (P = 0.064). Systolic blood pressure remained unchanged. CONCLUSION: The beneficial effects of rhGH replacement, described after short-term rhGH replacement, are sustained in the long term up to 7 years.

Non-hyperinsulinemic hypoglycemia in a patient with a gastrointestinal stromal tumor.

One of the authors (JvD) recently reported a case of non-islet cell tumor hypoglycemia caused by the production of "big" IGF-II by a gastrointestinal stromal tumor (GIST). Here, we report a patient with a GIST in whom non-hyperinsulinemic hypoglycemia was not attributable to aberrant tumoral IGF-II processing, but instead was caused by a combination of cachexia, renal and hepatic dysfunction, and tumoral glucose consumption.

Insect apolipophorin III: interaction of locust apolipophorin III with diacylglycerol.

In the formation of low-density lipophorin (LDLp) by the loading of diacylglycerol onto high-density lipophorin (HDLp) in insect hemolymph, apolipophorin III (apoLp-III) plays an essential role by binding to the increasing surface of the expanding lipoprotein particle. The present data on the surface properties of apoLp-III from Locusta migratoria demonstrate a preferential interaction with diacylglycerol. Injection of apoLp-III underneath a diacylglycerol monolayer results in a rapid interaction with the lipid; interaction with a phosphatidylcholine monolayer was considerably less. Locust apoLp-III binds with high affinity (Kd = 7.9.10(-9) M) to 1,2-diacylglycerol, which is consistent with its function in the LDLp particle; affinity for phosphatidylcholine is considerably lower. While the molecular area of locust apoLp-III in a monolayer is 2080 A2/molecule at the collapse pressure, in mixed monolayers of apoLp-III and lipid, the mean molecular area is decreased. Deglycosylation of the apoLp-III did not affect its interfacial stability. ApoLp-III from the moth Manduca sexta, which we included for comparison, demonstrated a similar reduction in molecular area resulting from interaction with lipid. These data do not support the hypothesis that interaction of apoLp-III with a lipid surface will lead to doubling of the molecular area of the protein (Kawooya, J.K., Meredith, S.C., Wells, M.A., Kézdy, F.J. and Law, J.H. (1986) J. Biol. Chem. 261, 13588-13591). The area of locust apoLp-III of 12.9 A2/amino acid residue at the collapse pressure is consistent with monolayers of alpha-helical proteins; circular dichroic spectra confirm a high alpha-helix content. The surface properties of apoLp-III reported here enable a high surface concentration of diacylglycerol in the LDLp particle, allowing the lipoprotein to act as an efficient reutilizable lipid shuttle.

Purification and characterization of the respiratory nitrate reductase of Bacillus licheniformis.

1. Respiratory nitrate reductase of Bacillus licheniformis was extracted from the bacterial membranes by treatment with deoxycholate and purified to a homogeneous state by means of gel chromatography and anion-exchange chromatography. 2. The enzyme (Mr = 193,000, s20, w = 8.6) consists of two subunits, having apparent molecular weight of 150,000 (alpha subunit) and 57,000 (beta subunit), which are present in an equimolar ratio. It does not contain carbohydrate. Ageing of the enzyme appears to result in splitting of the polypeptide chains at specific sites followed by dissociation and reassociation of the digestion products in various combinations. 3. In contrast to Klebsiella aerogenes repiratory nitrate reductase, which is isolated in a tetrameric form that can be reversibly dissociated into a monomeric form by detergents, B. licheniformis nitrate reductase, after isolation, is always present in a monomeric form. This property is related to the difference in membrane localization of the enzyme in the two organisms. 4. B licheniformis nitrate reductase contains 6.9 atoms of non-heme iron, 6.7 atoms of acid-labile sulfide and 0.93 atoms of molybdenum per molecule of enzyme. The molybdenum seems to be part of a low-molecular weight peptide Mo-cofactor) to which it may be bound by interaction with thiol-groups. 5. Antiserum against the native enzyme contains antibodies against both subunits as well as the Mo-cofactor. The Mo-cofactor does not have any antigenic determininants in common with either the alpha or the beta subunit. Also neither subunit cross-reacts with antiserum against the other subunit. Whereas the respiratory nitrate reductases from K. aerogenes and Escherichia coli are immunologically related, the native enzyme from B. licheniformis does not show any cross-reaction with antiserum prepared against either the K. aerogenes or the E. coli enzyme.

Homozygous and heterozygous expression of a novel insulin-like growth factor-I mutation.

IGF-I is a key factor in intrauterine development and postnatal growth and metabolism. The secretion of IGF-I in utero is not dependent on GH, whereas in childhood and adult life, IGF-I secretion seems to be mainly controlled by GH, as revealed from studies on patients with GHRH receptor and GH receptor mutations. In a 55-yr-old male, the first child of consanguineous parents, presenting with severe intrauterine and postnatal growth retardation, microcephaly, and sensorineural deafness, we found a homozygous G to A nucleotide substitution in the IGF-I gene changing valine 44 into methione. The inactivating nature of the mutation was proven by functional analysis demonstrating a 90-fold reduced affinity of recombinantly produced for the IGF-I receptor. Additional investigations revealed osteoporosis, a partial gonadal dysfunction, and a relatively well-preserved cardiac function. Nine of the 24 relatives studied carried the mutation. They had a significantly lower birth weight, final height, and head circumference than noncarriers. In conclusion, the phenotype of our patient consists of severe intrauterine growth retardation, deafness, and mental retardation, reflecting the GH-independent secretion of IGF-I in utero. The postnatal growth pattern, similar to growth of untreated GH-deficient or GH-insensitive children, is in agreement with the hypothesis that IGF-I secretion in childhood is mainly GH dependent. Remarkably, IGF-I deficiency is relatively well tolerated during the subsequent four decades of adulthood. IGF-I haploinsufficiency results in subtle inhibition of intrauterine and postnatal growth.

IGF-1 Levels, Complex Formation, and IGF Bioactivity in Growth Hormone-Treated Children With Prader-Willi Syndrome.

CONTEXT: Children with Prader-Willi syndrome (PWS) attain high-serum immunoreactive IGF-1 levels during a standard-dose GH treatment, which leads to concern, but lowering the dose deteriorates their body composition. OBJECTIVE: The objective of the study was to evaluate serum IGF-1, IGF binding protein (IGFBP)-3, and acid-labile subunit (ALS) levels, complex formation, and IGF bioactivity in GH-treated PWS children. DESIGN: This was a cross-sectional study. SETTING: The setting of the study was a Dutch PWS cohort. PARTICIPANTS: Forty GH-treated PWS children compared with 41 age- and sex-matched healthy controls participated in the study. INTERVENTIONS: Interventions included GH treatment (1.0 mg/m(2) · d = ∼0.035 mg/kg · d). MAIN OUTCOME MEASURES: Serum IGF-1, IGFBP-3, and ALS levels, complex formation, and IGF bioactivity by IGF-1 receptor kinase activation assay were measured. RESULTS: Serum IGF-1, IGFBP-3, and ALS levels and IGF-1 to IGFBP-3 ratio were significantly higher in GH-treated PWS children than in healthy controls. The 150-kDa ternary complex formation was, however, also significantly higher than in controls, indicating that most of serum IGF-1 is sequestered in the ternary 150-kDa complex with ALS and IGFBP-3. Young GH-treated PWS children [median (interquartile range) aged 5.2 (4.3-7.2) y] exhibited higher serum IGF bioactivity than controls, but no difference was observed in IGF bioactivity between older GH-treated PWS children, aged 14.9 (13.8-16.2) years, and controls. The proportion of IGF bioactivity of total serum IGF-1 was, however, lower in GH-treated PWS children than in controls. Serum immunoreactive IGF-1 levels did not correlate with IGF bioactivity in GH-treated children with PWS, in contrast to a strong positive correlation in healthy controls. CONCLUSIONS: In GH-treated PWS children, most serum IGF-1 is sequestered in the 150-kDa complex. Higher IGF bioactivity was found only in young GH-treated PWS children and not in the older ones. IGF bioactivity during GH showed a wide variation, and there was a disrupted correlation with immunoreactive IGF-1 levels, which makes immunoreactive IGF-1 levels an inappropriate indicator for GH dosing in PWS children.

Partial characterization of fimbriae of Xanthomonas campestris pv. hyacinthi.

Xanthomonas campestris pv. hyacinthi is a plant-pathogenic bacterium that causes yellow disease in Hyacinthus. X. c. pv.hyacinthi produces monopolarly attached fimbriae with a diameter of approximately 5 nm and a length of at least 6 micron. Fimbriae were purified by acid precipitation and preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. No hemagglutinating activity of purified fimbriae was found when the fimbriae were tested with several types of erythrocytes. The fimbrial protein subunit had a relative molecular mass of 17 kDa; an isoelectric point was found at pH 4.1. Analysis of the N-terminal amino acid sequence of the fimbrial subunit indicated that X. c. pv. hyacinthi expresses type 4 fimbriae. A polyclonal rabbit antiserum was raised against the purified fimbriae. This antiserum recognized fimbriae of X. c. pv. hyacinthi in immunogold electron microscopy and immunoblotting experiments. Immunofluorescence studies showed that X. c. pv. hyacinthi cells as well as purified native fimbriae were attached to stomata of hyacinth leaves, suggesting a role for these surface antigens in the first stages of yellow disease.