Optimal provision of daytime NPH insulin in patients using the insulin analog lispro

OBJECTIVE: Insulin lispro improves early postprandial blood glucose control but can result in late interprandial hyperglycemia. As an approach to resolving this problem, we performed a randomized, crossover study with four treatment arms, comparing the daytime metabolic profile after either premeal lispro alone or premeal lispro with optimal daytime NPH insulin and with standard human regular insulin. RESEARCH DESIGN AND METHODS: Twelve C-peptide negative type 1 diabetic patients were studied on four separate study days, at least 7 days apart. On each study day, patients received one of the four study insulin treatments, in random order, with identical meals and snacks. The four treatments were 1) premeal human regular insulin before lunch and supper at unchanged dose; 2) premeal lispro (unchanged dose) at lunchtime and dinner; 3) pre-lunch reduced-dose lispro (70%) before lunch and supper with supplemental lunchtime NPH and with a 6-h interval until dinner; and 4) pre-lunch reduced-dose lispro (70%) before lunch and supper with supplemental lunchtime NPH and with a 8-h interval until dinner. All patients were using their usual premeal plus basal insulin regimen during the period of the study, with human regular insulin before meals and NPH insulin at bedtime. RESULTS: Postprandial blood glucose concentrations (1230-1500) were lower after reduced or usual lispro dose compared with human regular insulin (5.5+/-0.2 and 5.6+/-0.2 vs. 8.2+/-0.5 mmol/l, P < 0.001), with no difference between the lispro doses. However, prepran-Dial (1800) blood glucose levels deteriorated to higher levels after usual-dose lispro alone compared with either human regular insulin (P < 0.05) or reduced-dose lispro plus NPH (P < 0.05) (8.9+/-0.3 vs. 7.1+/-0.8 and 6.4+/-0.4 mmol/l), with no difference between human regular insulin and reduced-dose lispro plus NPH. During the 2 h between the usual and delayed mealtime, blood glucose concentrations remained controlled on lispro plus NPH (2000: 6.5+/-0.4 mmol/l). CONCLUSIONS: Reduced-dose lunchtime lispro plus NPH maintained the improvement in postprandial blood glucose control with no deterioration in interprandial blood glucose control, even up to a late meal.     

Effects of sinoaortic denervation on Fos expression in the brain evoked by hypertension and hypotension in conscious rabbits

We have previously shown [Li and Dampney (1994) Neuroscience 61, 613-634] that periods of sustained hypertension and hypotension each induces a distinctive and reproducible pattern of neuronal expression of Fos (a marker of neuronal activation) in specific regions of the brainstem and forebrain of conscious rabbits. The aim of this study was to determine the contribution of afferent inputs from arterial baroreceptors to the activation of neurons in these various brain regions that is caused by a sustained change in arterial pressure. Experiments were carried out on rabbits in which the carotid sinus and aortic depressor nerves were cut in a preliminary operation. Following a recovery period of seven to 10 days, a moderate hypertension or hypotension (increase or decrease in arterial pressure of 20-30 mmHg) was induced in conscious barodenervated rabbits for 60 min by the continuous infusion of phenylephrine or sodium nitroprusside, respectively. In control experiments, barodenervated rabbits were subjected to the identical procedures except that they were infused with the vehicle solution alone. Compared with the effects seen in barointact rabbits, [Li and Dampney (1994) Neuroscience 61, 613-634] the number of neurons that expressed Fos in response to hypertension was reduced by approximately 90% in the nucleus of the solitary tract and in the caudal and intermediate parts of the ventrolateral medulla. In supramedullary regions, baroreceptor denervation resulted in a reduction of approximately 60% in hypertension-induced Fos expression in the central nucleus of the amygdala and in the bed nucleus of the stria terminalis, but no significant reduction in the parabrachial complex in the pons. Following hypotension, the number of neurons that expressed Fos in barodenervated rabbits, compared with barointact rabbits, [Li and Dampney (1994) Neuroscience 61, 613-634] was reduced by approximately 90% in the nucleus of the solitary tract, area postrema, and caudal, intermediate and rostral parts of the ventrolateral medulla. Baroreceptor denervation also resulted in a similar large reduction in hypotension-induced Fos expression in many supramedullary regions (locus coeruleus, midbrain periaqueductal grey, hypothalamic paraventricular nucleus, and in the central nucleus of the amygdala and the bed nucleus of the stria terminalis in the basal forebrain). In the supraoptic nucleus, hypotension-induced Fos expression in barodenervated rabbits was reduced by 75% compared to barointact animals, but was still significantly greater than in control animals. There was also a high level of Fos expression, much greater than in control animals, in the circumventricular organs surrounding the third ventricle (subfornical organ and organum vasculosum lamina terminalis). The results indicate that in conscious rabbits the activation of neurons that occurs in several discrete regions at all levels of the brain following a sustained change in arterial pressure is largely dependent upon inputs from arterial baroreceptors, with the exception of neurons in the circumventricular organs surrounding the third ventricle that are activated by sustained hypotension. The latter group of neurons are known to project to vasopressin-secreting neurons in the supraoptic nucleus, and may therefore via this pathway trigger the hypotension-induced release of vasopressin that occurs in the absence of baroreceptor inputs.     

Convexity-preserving fairing

This paper develops a two-stage automatic algorithm for fairing C²-continuous cubic parametric B-splines under convexity, tolerance and end constraints. The first stage is a global procedure, yielding a C² cubic B-spline which satisfies the local-convexity, local-tolerance and end constraints imposed by the designer. The second stage is a local finefairing procedure employing an iterative knot-removal knotreinsertion technique, which adopts the curvature-slope discontinuity as the fairness measure of a C² spline. This procedure preserves the convexity and end properties of the output of the first stage and, moreover, it embodies a globaltolerance constraint. The performance of the algorithm is discussed for four data sets.     

Survival and water-balance characteristics of unfed adult Amblyomma cajennense (Acari: Ixodidae)

The specific type of phospholipase A2 (PLA2) involved in formation of leukotriene B4 (LTB4) and platelet activating factor (PAF) in inflammatory cells has been controversial. In a recent report we characterized activation of the 'cytosolic' form of PLA2 (cPLA2) in human neutrophils (PMN) permeabilized with Staphylococcus aureus alpha-toxin under conditions where the secretory form of PLA2 (sPLA2) was inactive. In the current study, generation of both LTB4 and PAF in porated PMN are demonstrated. PMN, prelabeled with [3H]arachidonic acid (3H-AA, to assess AA release and LTB4 production) or with 1-O-[9',10'-3H]hexadecyl-2-lyso-glycero-3-phosphocholine (3H-lyso-PAF, for determination of lyso-PAF and PAF formation), were permeabilized with alpha-toxin in a 'cytoplasmic' buffer supplemented with acetyl CoA. Maximum production of both PAF and LTB4 required addition of 500 nM Ca2+, G-protein activation induced with 10 microM GTP gamma S, and stimulation with the chemotactic peptide, N-formyl-Met-Leu-Phe (FMLP, 1 microM); LTB4 production was confirmed by radioimmunoassay. Removal of acetyl CoA from the system had little effect on LTB4 generation but blocked PAF production with a concomitant increase in lyso-PAF formation LTB4 and PAF production occurred in parallel over time and at differing ATP and Ca2+ concentrations. Further work demonstrated that: (i) maximum production of both inflammatory mediators required a hydrolyzable form of ATP; (ii) blocking phosphorylation with staurosporin inhibited production of both; (iii) the reducing agent, dithiotreitol, had little affect on LTB4 formation but slightly enhanced PAF generation. This study clearly shows that cPLA2 activation can provide precursors for both LTB4 and PAF, that maximum PAF and LTB4 formation occur under conditions that induced optimal cPLA2 activation, that a close coupling between LTB4 and PAF formation exists, and that, after substrate generation, no additional requirements are necessary for LTB4 and PAF generation in the permeabilized PMN system.     

Microstructure modelling for property prediction and control

The development of microstructure models to predict the final mechanical properties of hot rolled steels is reviewed. Particular emphasis is placed on the performance of these models in solving industrial problems, or for online control. While there is still ongoing activity to improve these models they are still not sufficiently accurate for many applications and there are a number of issues associated with full implementation.     

Magnetic resonance imaging changes after stereotactic radiation therapy for childhood low grade astrocytoma

BACKGROUND: Stereotactic radiotherapy (SRT) is fractionated radiotherapy delivered under stereotactic guidance to produce highly focal and precise therapy. We studied the incidence of imaging changes that can mimic tumor progression after completion of SRT for childhood low grade astrocytoma. METHODS: Between June 1992 and September 1994, we prospectively treated 28 children with low grade astrocytomas with SRT. The patients ranged in age from 2 to 22 years (median: 10 yrs) and none had received prior radiation therapy or radiosurgery. Routine fractionation was employed (180-200 centigray[cGy]) to a total dose of 5220-6000 cGy over 5 to 6 weeks. All of the patients underwent initial and follow-up magnetic resonance imaging (MRI) according to protocol. RESULTS: Median clinical follow-up for the 28 patients was 24 months (range, 5-32 mos) with a median radiographic follow-up of 15 months (range, 3-26 mos). Fifteen patients had reduction in tumor size, one patient had stable disease. Twelve patients (43%) developed increased size of the lesion, increased signal intensity or enhancement, cysts or cavitations, and an increase in edema or mass effect on follow-up MRI. Most of these changes occurred between 9 and 12 months after the start of SRT and resolved or decreased by 15 to 21 months. All but one patient had normal or stable neurologic examinations. CONCLUSIONS: Treatment-related MRI changes are common after conventionally fractionated schedules using stereotactic radiation techniques for patients with low grade astrocytomas. These changes can be distinguished from tumor progression by their transient nature as well as the general absence of clinical symptoms.     

Thalidomide responsive chronic pulmonary GVHD

A 29-year-old male underwent allogeneic bone marrow transplantation for progressive multiple myeloma. His post-transplant course was complicated by severe chronic pulmonary graft-versus-host disease (GVHD) resistant to cyclosporin A, corticosteroids and azathioprine. The introduction of thalidomide resulted in a dramatic improvement in his lung function which has been maintained even after cessation of thalidomide. He remains well 40 months after transplantation.     

Apamin-sensitive Ca(2+)-activated K+ channels regulate pacemaker activity in nigral dopamine neurons

Mesencephalic dopamine-containing neurons exhibit a Ca(2+)-dependent oscillation in membrane potential believed to underlie the ability of these cells to maintain spontaneous activity in the absence of afferent synaptic drive. In the present series of experiments, sharp electrode intracellular recording techniques were used in conjunction with an in vitro brain slice preparation to explore the ionic mechanisms underlying rhythmogenesis in nigral dopamine neurons in the rat. Our results indicate that the K+ channel producing the prolonged post-spike afterhyperpolarization exhibited by these neurons is also principally responsible for generating the falling phase of the autogenous pacemaker oscillation. Alterations in the expression of this conductance are associated with marked changes in neuronal firing pattern, indicating that modulation of ligand-gated Ca(2+)-activated K+ channels may constitute a functional means of altering temporal coding among the major mesotelencephalic dopamine systems.