Granulocyte-colony stimulating factor in the treatment of colchicine poisoning

1. Colchicine is a highly active alkaloid used in the treatment of gouty arthritis and pseudogout. In overdose colchicine inhibits cell division effecting organs with a high rate of cell turn-over, such as the gastrointestinal tract and bone marrow. Early fatality results from cardiovascular collapse and respiratory failure, however pancytopenia and overwhelming septicaemia can occur later. 2. We describe a case of suicidal ingestion of 25-30 mg of colchicine in a previously healthy 43-year-old woman. Initial symptoms were mainly gastrointestinal. By day 5 she had developed severe pancytopenia and early sepsis, which were successfully treated using granulocyte colony stimulating factor (G-CSF) 600 micrograms s.c. 3. In vitro G-CSF is produced by the haematopoietic system. However, G-CSF can now be produced by recombinant DNA cloning technology and thus is available clinically. 4. There is no recognised antidote for colchicine poisoning and treatment is symptomatic. Fab fragments may have a promising future in eliminating colchicine from the body, but are currently not clinically available. In those patients that survive the initial phase of poisoning, G-CSF offers an effective method of treating the pancytopenia and preventing overwhelming septicaemia. Daily monitoring of the patient's haematological status is strongly recommended.

Interaction of the low-affinity receptor CD23/Fc epsilonRII lectin domain with the Fc epsilon3-4 fragment of human immunoglobulin E

CD23/Fc epsilonRII, the low-affinity receptor for IgE, is a multifunctional protein of importance in blood cell development and the immune system. We have studied the interaction of CD23 with IgE in solution using hydrodynamic methods applied to recombinant fragments of both ligands: sCD23, corresponding to the soluble lectin domain of CD23, and Fc epsilon3-4, a dimer of the C epsilon3-C epsilon4 sequence of IgE. The hydrodynamic, spectroscopic, and biological properties of these fragments suggest that they have a fully native structure. Sedimentation equilibrium studies on mixtures of sCD23 and Fc epsilon3-4 indicate that IgE has two binding sites for CD23, each characterized by affinities of approximately 10(5) M(-1). Analysis of the sedimentation as a function of temperature allows conclusions to be drawn about the thermodynamics of binding at the two sites. Binding at the first site is characterized by large changes in enthalpy (delta H(degree)To = -2.1 +/- 3.3 kcal mol(-1)) and heat capacity (delta Cp(degree) = -320 +/- 320 cal mol(-1) K(-1)), whereas binding at the second site is characterized by small changes in enthalpy (delta H(degree)To = 0.1 +/- 5.6 kcal mol(-1)) and heat capacity (delta Cp(degree) = -140 +/- 550 cal mol(-1) K(-1)). In native CD23, there are two or three lectin domains, associated through an alpha-helical coiled-coil stalk. The predicted structure of the CD23 oligomers and symmetry considerations rule out the possibility of two lectin domains from one oligomer binding to identical sites in IgE. The notion of two types of interaction in the 2:1 complex between CD23 and IgE is consistent with the thermodynamic data presented.

Mitogenic actions of endothelin and other growth factors in ovine endometrium

Endothelin-1 (ET-1) is present in ovine endometrium, primarily in epithelial cells, and increases around the time of implantation. We examined the cell type expressing ET-binding sites in vitro and whether ET-1 has mitogenic actions in the endometrium, alone or in synergy with other growth factors. Purified epithelial and stromal cells were prepared from luteal-phase endometrium. Specific receptors were demonstrated by binding of 125I-ET-1 and proliferative effects of ET-1 and/or other growth factors determined by uptake of [3H]thymidine by cells in serum-free culture. 125I-ET-1 bound to both epithelial (2516 +/- 820 c.p.m./well) and stromal (6368 +/- 1350 c.p.m./well) cells and was displaced by ET-1 (1 mumol l-1). There were no proliferative effects of ET on epithelial cells. ET-1 (10 nmol l-1) stimulated uptake of [3H]thymidine by stromal cells under serum-free conditions in 13/20 individual cell preparations, to 149 +/- 13% of control (untreated = 100%) with dose-dependence between the range of 1 to 100 nmol l-1. Stimulation by fetal calf serum was to 377 +/- 126% of control. The effects on proliferation by other growth factors (dose; % of control +/- S.E.M., number of positive/total number of cell preparations) were: IGF-I (13 nmol l-1; 182 +/- 14, 4/4), epidermal growth factor (EGF; 4.8 nmol l-1; 132 +/- 5%, 7/7), platelet-derived growth factor-BB (0.4 nmol l-1; 146 +/- 3, 2/2) and leukaemia inhibitory factor (0.4 nmol 1-1; 110 +/- 2, 3/3). All stimulations except that of EGF were significant and dose-responsive but only insulin was additive with ET (350 +/- 35, 5/5). ET-1 also stimulated expression of the the AP-1 cis element c-jun, this being maximal at 60 min of exposure to mitogen. ET-1, along with other growth factors has a likely paracrine role in cellular proliferation in the endometrium, possibly in association with blastocyst implantation.

Oxygen delivery, oxygen consumption, and gastric intramucosal pH are not improved by a computer-controlled, closed-loop, vecuronium infusion in severe sepsis and septic shock

OBJECTIVE

To investigate the influence of the neuromuscular blocking agent vecuronium on oxygen delivery (DO2), oxygen consumption (VO2), oxygen extraction ratio, and gastric intramucosal pH in heavily sedated patients with severe sepsis or septic shock.

DESIGN

Prospective, randomized, placebo-controlled, cross-over trial.

SETTING

University hospital intensive care unit.

PATIENTS

Eighteen mechanically ventilated patients with severe sepsis or septic shock.

INTERVENTIONS

All patients were heavily sedated. After baseline measurement, a computer-controlled, closed-loop infusion of either vecuronium or saline was initiated and further measurements were made at 40 and 60 mins. The procedure was repeated with the alternative agent after return of neuromuscular function.

MEASUREMENTS AND MAIN RESULTS

DO2, VO2, intramucosal pH were monitored using pulmonary artery catheters, a gas exchange monitor, and gastric tonometers. Changes from baseline were compared (paired t-test, p = .05). The vecuronium closed-loop infusion achieved T1 between 5% and 15% at 40 mins. There was a significant difference in the changes from baseline for static respiratory compliance in the vecuronium closed-loop infusion group compared with the saline closed-loop infusion group. There was no significant difference in the change from baseline for systemic or pulmonary vascular resistance, DO2, VO2, oxygen extraction ratio, or intramucosal pH.

CONCLUSIONS

In these patients, vecuronium infusion achieved the targeted level of paralysis and improved respiratory compliance but did not alter intramucosal pH, VO2, DO2, or oxygen extraction ratios. With deep sedation, neuromuscular blockade in severe sepsis/septic shock does not significantly influence oxygen flux and should be abandoned as a routine method of improving tissue oxygenation in these patients.

Paranodal structure in diabetic sensory polyneuropathy

Observations have been made on the structure of the paranodal region at nodes of Ranvier in the sural nerve of patients with diabetic sensory polyneuropathy. The structure of the paranodes was examined with particular attention to the definition and assessment of axoglial dysjunction, which has been claimed to be a characteristic feature of both human and experimental diabetic neuropathy and which has been related to paranodal swelling. In the present series of cases it was not possible to confirm that axoglial dysjunction is a distinctive feature of diabetic polyneuropathy in fibres not undergoing active demyelination or wallerian-type degeneration, neither was excessive paranodal enlargement found.

Ranitidine therapy for esophagitis in children with developmental disabilities

Esophagitis is common in children with cerebral palsy. Because histamine2-receptor antagonists such as ranitidine have not been uniformly effective, we treated disabled children with esophagitis with greater than usual doses. Endoscopy and pH monitoring were used to monitor dose and response to treatment. A dose of 9.3 +/- 0.9 mg/kg/day did not improve visual or microscopic esophagitis after 3 months. A dose of 14.8 +/- 3.9 mg/kg/day resulted in only slight microscopic improvement, but symptoms were improved. There was no correlation between esophageal reflux index at enrollment and either severity of esophagitis or response to treatment. Elevation of gastric pH by ranitidine was infrequent. These results affirm that pH monitoring does not reliably identify disabled children with reflux esophagitis nor does ranitidine reliably heal this disorder.

Upper airway obstruction caused by acquired inhibitor to factor VIII

Bleeding caused by inhibitors to factor VIII is a rare medical emergency requiring immediate specialist investigation and management. Urgent initiation of therapy with high dose factor VIII concentrates may be life saving. Successful management of acute upper airway obstruction from uncontrolled haemorrhage into the oropharyngeal tissues should be achieved with fibreoptic guided nasotracheal intubation.

Pediatric constipation

The purpose of this article is to present an overview of pediatric constipation. Discussion of the definition from a medical and nursing point of view is included. Intestinal pathophysiology as well as etiological theories of pediatric constipation are reviewed. Current research to date and clinical treatment and experience in the area are presented. A rationale for further nursing research in this area is described.

Comparison of intrathoracic and intra-abdominal measurements of central venous pressure

BACKGROUND

Complications can arise from standard intrathoracic central venous pressure (CVP) measurements in critically ill, mechanically ventilated patients. We have assessed the feasibility of catheterisation by the femoral route to measure CVP in the abdomen (ACVP). We compared measurements by the standard jugular or subclavian route (TCVP) with simultaneous ACVP measurements by the femoral route.

METHODS

Between June, 1994 and May, 1995, we recruited 20 critically ill adult patients with various disorders; all patients already had a TCVP line in situ. We placed a femoral catheter in the inferior vena cava close to the right atrium under electrocardiographic guidance. The catheter position was confirmed (and corrected if necessary) by chest radiography. CVP was measured from both sites hourly for 6 h. Positive end-expiratory pressure, mean airway pressure, and intra-abdominal pressure were recorded simultaneously.

FINDINGS

One patient was excluded because radiography showed that the catheter position was incorrect. For 133 paired measurements of ACVP and TCVP in the remaining 19 patients, the mean difference was 0.45 mm Hg (SD 0.89: 95% Cl 0.30-0.60); the limits of agreement were -1.33 to 2.23 mm Hg (-1.63 to 2.53). We found a small tendency for the difference between ACVP and TCVP to increase as positive end-expiratory pressure and mean airway pressure increased; the difference was statistically, but not clinically, significant.

INTERPRETATION

Our study showed that for clinical purposes CVP can be measured by a femoral catheter placed in the abdominal inferior vena cava near the right atrium. This approach can replace standard TCVP measurements in critically ill, mechanically ventilated patients.

Fatal acute hepatorenal failure following potassium permanganate ingestion

Potassium permanganate (KMnO4), a powerful oxidizing agent, is readily available without prescription. Tissue contact produces coagulation necrosis and the lethal consequences of oral ingestion are well described, with most deaths because of airway oedema and obstruction or circulatory collapse. Whilst systemic toxicity is reported, its mechanism is unclear. We describe a case of suicidal ingestion of KMnO4 followed by acute hepatorenal toxicity resulting in the death of the patient. The clinical course bore close resemblance to that of severe paracetamol overdose. We discuss the pathogenesis of the systemic toxicity of KMnO4 and postulate that it is due to oxidative injury from free radicals generated by the absorbed permanganate ion. We recommend that N-acetyl cysteine be given within the first few hours to all patients with potassium permanganate poisoning.

Reduced insulin-like growth factor binding protein-1 (IGFBP-1) levels correlate with increased cardiovascular risk in non-insulin dependent diabetes mellitus (NIDDM)

IGF-I and -II levels are altered in patients with atherogenic lipid profiles and may contribute to the development of macrovascular disease in NIDDM. We examined cardiovascular risk factors, IGF-I, IGF-II and IGFBP-1 in 74 NIDDM patients analysed as a whole group and according to treatment type. IGF-I was not significantly associated with cardiovascular risk factors but IGF-II levels correlated positively with total and LDL cholesterol most markedly in the diet treated group (0.72, p < 0.01 and 0.76, p < 0.01 respectively). In the whole group reduced IGFBP-1 levels were significantly associated with factors known to increase cardiovascular risk: i.e. low HDL cholesterol (0.31, p < 0.01) and elevated blood pressure (-0.35, p < 0.01), BMI (-0.37, p < 0.01), insulin (-0.29, p < 0.01) and proinsulin (-0.24, p < 0.01). In the treatment groups IGFBP-1 was lower in patients on diet alone (n = 11, 42.6 +/- 11.6 mu g/l) and sulphonylurea +/- insulin (n = 39, 53.2 +/- 7.6 mu g/l) relative to insulin treatment (n = 24, 103.0 +/- 19, 7 mu g/l, p < 0.05). The lower levels of IGFBP-1 were not due to a significant change in phosphorylation status from the highly phosphorylated circulating form since lesser and non-phosphorylated variants were undetectable in 53/74 patients. Multiple regression analysis revealed the best predictors of IGFBP-1 were BMI and MAP (R2 = 0.2. p < 0.001) and for blood pressure, IGFBP-1 and age (R2 = 0.47, p < 0.001). These findings indicate that in NIDDM patients low IGFBP-1 levels are associated with multiple factors predisposing to atherogenesis.

Bent domain structure of recombinant human IgE-Fc in solution by X-ray and neutron scattering in conjunction with an automated curve fitting procedure

Human immunoglobulin E (IgE) consists of 14 domains, each with the characteristic immunoglobulin fold structure. Compared with the 12-domain structure of immunoglobulin G (IgG), IgE has an additional pair of domains (C epsilon 2) in the Fc region in place of the hinge of IgG. The crystal structure of the 4-domain Fc fragment of IgG is known, but not that of the 6-domain Fc fragment of IgE (IgE-Fc). In order to elucidate the position of the C epsilon 2 domains in the domain structure of IgE-Fc, IgE-Fc was studied by synchrotron X-ray and pulsed neutron scattering. The upper limit on the X-ray radius of gyration RG which determines macromolecular elongation was determined to be 3.52 +/- 0.14 nm. That for the neutron RG (measured in 100% 2H2O buffers) was 3.53 +/- 0.05 nm. The X-ray and neutron cross-sectional radii of gyration were 1.89 +/- 0.05 and 1.56 +/- 0.09 nm, respectively. The scattering curves were modeled on the basis of a previously-predicted model for IgE-Fc (Helm, B. A., Ling, Y., Teale, C., Padlan, E. A., & Brüggemann, M. (1991) Eur. J. Immunol. 21, 1543-1548). The extended arrangement of domains in that model resulted in poor agreement with experimental data. Interactive and automated procedures for the fitting of crystallographically-derived domain models to scattering data were developed. Each pair of C epsilon 2, C epsilon 3, and C epsilon 4 domains was translated and rotated relative to the remaining structure in a comprehensive five-parameter search of more than 37,000 models. Substantially improved agreement between the experimental and calculated scattering curves was obtained. Bent models for IgE-Fc in which the C epsilon 2 domain pair is rotated by at least 40-50 degrees from its position in the previously predicted linear IgE model consistently gave the best agreement with the X-ray and neutron scattering curves. Such a structure for the Fc fragment accounts in part for the bent structure previously proposed for intact human IgE, which is important for understanding the interaction between IgE and its receptors.

Myelinated nerve fibre regeneration in diabetic sensory polyneuropathy: correlation with type of diabetes

Observations were made on myelinated fibre regeneration in diabetic sensory polyneuropathy assessed in sural nerve biopsy specimens. These confirmed that regenerative clusters initially develop within abnormally persistent Schwann cell basal laminal tubes. The number of regenerating fibres, identified by light microscopy, was found to decline in proportion to the reduction in total myelinated fibre density. The relative number of regenerating fibres was significantly greater in patients with insulin-dependent as compared with those with non-insulin-dependent diabetes after correction for age. There was a slight negative correlation between the relative proportion of regenerating fibres and age, but this was not statistically significant. The progressive reduction in the number of regenerating fibres with declining total fibre density indicates that axonal regeneration fails with advancing neuropathy. The production of nerve growth factor (NGF) and NGF receptors by denervated Schwann cells is likely to be important for axonal regeneration. To investigate whether the failure of axonal regeneration could be related to a lack of NGF receptor production by Schwann cells, we examined the expression of p75 NGF receptors by Büngner bands immunocytochemically. In comparison with other types of peripheral neuropathy, p75 NGF receptor expression appeared to take place normally. It is concluded that failure of axonal regeneration constitutes an important component in diabetic neuropathy. Its explanation requires further investigation.

Action of metallic ions on the precocious development by rabbit sperm of motion patterns that are characteristic of hyperactivated motility

An earlier study demonstrated that rabbit sperm incubated for 16 hr under capacitation conditions acquire motility patterns identical to those seen in rabbit sperm capacitated in vivo. We now show that similar motion patterns develop after 0.5 hr incubation in a Tris-buffered medium, medium M. Development and decline of the motion patterns occurred in three phases each recognized by the character of the biphasic motion patterns. Hyperactivated sperm were objectively identified and quantified by a previously developed computer-directed model. The percentage of motile sperm that acquired hyperactivated motility and the period they remained in this state varied among sperm from different rabbits. The decline in hyperactivated motility was paralleled by a decrease in the average sperm curvilinear velocity (VCL) and average amplitude of lateral head displacement (AALH), but was not accompanied by a concomitant decrease in percentage of motile sperm. Pb2+ and Cd2+, at concentrations that did not inhibit motility, prevented development of hyperactivated motility. Inhibition of hyperactivated motility by Pb2+ was time- and concentration-dependent; the average percentage of hyperactivated sperm decreased from approximately 30% to < 5% (n = 5) in 1 hr at a Pb2+ concentration of 25 microM. Cd2+ inhibition of hyperactivation was dependent only on concentration of the cation. At a concentration of 100 microM, the decrease in the percent of hyperactivated sperm was approximately 50% (n = 3). Hg2+, Zn2+, and Cr6+ at sublethal concentrations had no effect on hyperactivated motility development. These results suggest that Pb2+ and Cd2+, by virtue of their ability to prevent the wide curvature flagella beating that is characteristic of hyperactivation, can compromise fertilization at concentrations that do not inhibit sperm motility and act as a reproductive toxicant at a level other than spermatogenesis.

Choice of treatment affects plasma levels of insulin-like growth factor-binding protein-1 in noninsulin-dependent diabetes mellitus

Insulin-like growth factor (IGF)-binding protein-1 (IGFBP-1) modulates the metabolic and mitogenic effects of IGFs. Although IGFBP-1 levels are abnormally high in insulin-dependent diabetes (IDDM), relatively little is known in NIDDM; conflicting data have suggested both high and low levels. We investigated whether treatment modifies IGFBP-1 levels in two groups of NIDDM patients. Study 1 examined fasting concentrations in groups of patients with NIDDM, comparable except for treatment type (sulfonylurea, n = 23; once daily insulin, n = 15; sulfonylurea plus once daily insulin, n = 14; multiple insulin injections, n = 9) and 25 nondiabetic subjects. In sulfonylurea-treated patients there were markedly reduced plasma IGFBP-1 concentrations (median, interquartile range in parentheses): control, 61.0 (36-96) micrograms/L; sulfonylureas alone, 31.5 (21-61) micrograms/L (P < 0.01); and sulfonylureas plus insulin, 31.5 (9-53) micrograms/L (P < 0.01). Once daily insulin was associated with values similar to those in the control group [62.0 (27-103) micrograms/L; P = NS], whereas IGFBP-1 levels were higher with multiple insulin injection therapy [156.0 (71-184) micrograms/L; P < 0.05]. Proinsulin levels were higher in sulfonylurea-treated patients, but there was no significant correlation between IGFBP-1 and proinsulin within any individual group. Study 2 examined the effects of treatment on the dynamics of IGFBP-1 levels between 0800-1900 h. In control subjects (n = 8), levels fell from 0800 h (mean +/- SEM, 22.4 +/- 5.2 micrograms/L) to 1000 h (14 +/- 5.2 micrograms/L), followed by a rise, more rapid after food, to a peak at 1240 h (20.6 +/- 3.7 micrograms/L). Levels then declined until 1500 h (10.7 +/- 2.9 micrograms/L), with a further postprandial peak at 1840 h (23.1 +/- 3.2 micrograms/L). Sulfonylurea therapy (n = 6) resulted in a complete loss of this pattern, with a marked fall in IGFBP-1 from 0800 h (22 +/- 2.7 micrograms/L) to less than 7 micrograms/L for the remainder of the study (area under the curve, 1150-1400 h, P < 0.001 vs. control). By contrast, in metformin-treated patients (n = 7), neither IGFBP-1 levels nor postprandial peaks were significantly different from those in the control group. Our findings suggest that in patients with NIDDM, the regulation of IGFBP-1 is markedly influenced by the choice of treatment.

Cerebrospinal fluid levels of beta endorphin in painful and painless diabetic polyneuropathy

beta endorphin (beta-EP) is an important modulator of central pain pathways. To examine whether changes in central production of beta-EP contribute to the pathogenesis of diabetic neuropathic pain, we compared the cerebrospinal fluid (CSF) levels of beta-EP and its precursor proopiomelanocortin (POMC) between 15 diabetic patients with chronic painful diabetic polyneuropathy, eight patients with severe painless diabetic neuropathy, and ten nondiabetic controls. Both peptides were measured by specific monoclonal antibody-based two-site immunoradiometric assays (IRMAs). In the diabetic patients with painful neuropathy, mean +/- SD CSF beta-EP concentrations (5.7 +/- 2.2 pmol/L) were comparable to those of the diabetic patients with painless neuropathy (6.0 +/- 2.3 pmol/L) and did not correlate with the severity of neuropathic pain. CSF beta-EP, but not POMC, concentrations were lower in the diabetic neuropathic patients overall (5.8 +/- 1.9 pmol/L) compared to the control subjects (7.6 +/- 2.2 pmol/L) (p < 0.05). CSF POMC showed no intergroup differences. However, POMC levels were 80-fold higher than those of beta-EP and should always be considered when interpreting immunoreactive beta-EP or other derivative peptide levels in CSF. We conclude that CSF beta-EP levels appear to be reduced in diabetic polyneuropathy but they do not relate to the presence of neuropathic pain. This might explain why opioid analgesics are of little, if any, help in alleviating diabetic neuropathic pain.

Hydrodynamic studies of a complex between the Fc fragment of human IgE and a soluble fragment of the Fc epsilon RI alpha chain

The interaction between immunoglobulin E (IgE) and its high-affinity receptor Fc epsilon RI is central to allergic disease. The binding site for Fc epsilon RI lies in the third constant region domain of the epsilon heavy chain of IgE (C epsilon 3). Identical epitopes on the two C epsilon 3 domains in the IgE-Fc are predicted to be on opposite sides of the structure, and therefore each could bind independently to a receptor molecule. Titrations, however, reveal that the IgE-Fc forms an equimolar complex with a soluble fragment of the Fc epsilon RI alpha chain (sFc epsilon RI alpha), and the molecular weight of the complex, as determined by sedimentation equilibrium, confirms this stoichiometry. The measured sedimentation coefficients of the two ligands are in good agreement with computed values for a compact IgE-Fc and an elongated sFc epsilon RI alpha structure. The calculated sedimentation coefficients for possible models of a 1:1 complex lead to exclusion of all highly extended geometries for the complex. Possible explanations for the paradoxical stoichiometry of the IgE-Fc/sFc epsilon RI alpha complex, in terms of the curved shape of IgE, a conformational change in IgE when the receptor binds, and steric interference between two molecules of Fc epsilon RI binding to identical sites, are discussed.

Secretion of recombinant human IgE-Fc by mammalian cells and biological activity of glycosylation site mutants

We have constructed an expression vector that leads to secretion of the whole Fc of human immunoglobulin E (hIgE-Fc) from mammalian cells at levels up to 100 mg/l of culture. Two surface glycosylation sites at Asn265 and Asn371 have been changed to glutamine, to obtain a more homogeneous preparation of hIgE-Fc for structural studies. Comparison of wild-type and mutant products revealed that Asn371 is rarely glycosylated in Chinese hamster ovary cells. Both the double mutant and wild-type hIgE-Fc bind to the high-affinity IgE receptor, Fc epsilon RI, with about the same affinity as myeloma IgE (Ka in the range 10(10)-10(11) M-1), and were able to sensitize isolated human basophils for anti-IgE triggering of histamine release. However, only the double mutant hIgE-Fc approached the affinity of myeloma IgE for the low-affinity receptor, Fc epsilon RII (Ka = 7.3 x 10(7) M-1), whereas the wild-type hIgE-Fc bound with a 10-fold lower affinity (Ka = 4.1 x 10(6) M-1).