Temperature correction of blood-gas and pH measurements

We critically review formulas for temperature correction of pH, pCO2, and pO2 measurements in whole blood and the clinical usefulness of these formulas. We discuss both the theoretical derivation and experimental verification of temperature-induced changes. We recommend when to use and when not to use these formulas, based upon the clinical interpretation of these assays.

Effects of a circulating factor in patients with essential hypertension on intracellular free calcium in normal platelets

Intracellular free (cytosolic) calcium has been reported to be increased in the platelets of patients with essential hypertension. We investigated the possibility that the high cytosolic calcium concentration may be caused by a circulating plasma factor, by incubating platelets from normotensive subjects with plasma ultrafiltrates from patients with essential hypertension. The cytosolic calcium concentration in normal platelets increased after incubation with plasma from patients with untreated hypertension (80 +/- 15 percent [+/- SEM]) or from patients in whom hypertension was well controlled by calcium-influx blockers (129 +/- 33 percent). In contrast, the cytosolic calcium concentration was unchanged after incubation with plasma from normotensive subjects. When platelets from the patients were incubated with plasma from the controls, cytosolic calcium in platelets decreased by more than 30 percent, into the normal range (P less than 0.01). These data demonstrate that plasma from patients with essential hypertension contains a substance that increases the cytosolic calcium concentration in platelets. Cytosolic calcium is a trigger for vascular smooth-muscle-cell contraction, and if the plasma factor acts on these cells as it acts on platelets, it may be responsible for the increased peripheral vascular resistance associated with hypertension.

RO 15-1788 antagonises the central effects of diazepam in man without altering diazepam bioavailability

1 In a double-blind, placebo controlled study, the efficacy of Ro 15-1788, a new benzodiazepine antagonist, in blocking the cognitive, psychomotor and subjective effects of diazepam, was investigated in a group of six healthy male volunteers. 2 The central effects of orally administered diazepam (40 mg) were most pronounced 1 h after dosing and persisted for 9 h with decreasing severity. 3 Concurrent oral administration of Ro 15-1788 (200 mg) completely prevented the impairment in cognitive and psychomotor function observed after diazepam alone. 4 The duration of action of Ro 15-1788 was shorter than that of diazepam. 5 Plasma diazepam levels after administration of the diazepam/antagonist combination were very similar to those observed following diazepam alone.

A mutant cholera toxin B subunit that binds GM1- ganglioside but lacks immunomodulatory or toxic activity

GM1-ganglioside receptor binding by the B subunit of cholera toxin (CtxB) is widely accepted to initiate toxin action by triggering uptake and delivery of the toxin A subunit into cells. More recently, GM1 binding by isolated CtxB, or the related B subunit of Escherichia coli heat-labile enterotoxin (EtxB), has been found to modulate leukocyte function, resulting in the down-regulation of proinflammatory immune responses that cause autoimmune disorders such as rheumatoid arthritis and diabetes. Here, we demonstrate that GM1 binding, contrary to expectation, is not sufficient to initiate toxin action. We report the engineering and crystallographic structure of a mutant cholera toxin, with a His to Ala substitution in the B subunit at position 57. Whereas the mutant retained pentameric stability and high affinity binding to GM1-ganglioside, it had lost its immunomodulatory activity and, when part of the holotoxin complex, exhibited ablated toxicity. The implications of these findings on the mode of action of cholera toxin are discussed.

The DST in psychiatric outpatients with generalized anxiety disorder, panic disorder, or primary affective disorder

The authors administered the dexamethasone suppression test (DST) to outpatients, who were free from psychoactive drugs for at least 10 days before the test, with primary affective disorder (N = 60), generalized anxiety disorder (N = 26), panic disorder (N = 22), and agoraphobia with panic attacks (N = 13). With a cortisol value of 5 micrograms/dl considered nonsuppression, there were no significant differences in dexamethasone nonsuppression rates among the diagnostic groups. Scores on the Hamilton Rating Scale for Depression and a melancholia subscale were significantly higher in the depressed group than in the anxiety disorder group. The findings raise questions concerning the specificity of the DST for primary affective disorder in relationship to anxiety disorders.

Ro 15-1788 antagonizes the effects of diazepam in man without affecting its bioavailability

In a double-blind, placebo-controlled three-way cross over study, the efficacy of Ro 15-1788 200 mg, a new benzodiazepine antagonist, in blocking the amnesic, cognitive, psychomotor and subjective effects of diazepam 20 mg, was investigated in a group of six healthy male volunteers. The amnesic effects of diazepam were markedly attenuated by the combined administration of Ro 15-1788. The psychomotor and subjective effects of diazepam by mouth were most pronounced 2.5 h after administration. Concurrent oral administration of Ro 15-1788 completely prevented these effects at 2.5 h. Plasma diazepam concentrations observed after administration of the combination of diazepam and the antagonist did not differ from those observed following diazepam alone.

Diabetes self-management programmes in older adults: a systematic review and meta-analysis

AIM

The evidence for self-management programmes in older adults varies in methodological approaches, and disease criteria. Using predetermined methodological criteria, we evaluated the effect of diabetes-specific self-management programme interventions in older adults.

METHODS

The EMBASE, MEDLINE and Cochrane Central Register of Controlled Trials databases were searched from January 1980 to November 2013, as were reference lists from systematic reviews, meta-analyses and clinical practice guidelines. A total of 13 trials met the selection criteria, which included 4517 older adult participants; 2361 participants randomized to a diabetes self-management programme and 2156 to usual care.

RESULTS

The pooled effect on HbA(1c) was a reduction of -2 mmol/mol (-0.2%; 95% CI -0.3 to -0.1); tailored interventions [-3 mmol/mol (-0.2%; 95% CI -0.4 to -0.1)] or programmes with a psychological emphasis [-3 mmol/mol (-0.2; 95% CI -0.4 to -0.1)] were most effective. A pooled treatment effect on total cholesterol was a 5.81 mg/dl reduction (95% CI -10.33 to -1.29) and non-significant reductions in systolic and diastolic blood pressure.

CONCLUSIONS

Diabetes self-management programmes for older adults demonstrate a small reduction in HbA(1c), lipids and blood pressure. These findings may be of greater clinical relevance when offered in conjunction with other therapies.

Absence of central effects in man of the benzodiazepine antagonist Ro 15-1788

The benzodiazepines are typified by a profile of side effects which includes drowsiness, ataxia and incoordination. Ro 15-1788, an imidazodiazepine derivative, exhibits marked antagonism of the behavioural and biochemical effects of the benzodiazepines in animals and man. It is devoid of any behavioural activity in animals, except at very high doses. In the present study the effects of single rising oral doses of Ro 15-1788 on cognitive, psychomotor and subjective function in man have been assessed using a battery of psychometric tests designed to identify the sedative action of the benzodiazepines. At all doses up to 600 mg, Ro 15-1788 demonstrated none of the classical behavioural effects of the benzodiazepines.

Decreased calcium pump adenosine triphosphatase in red blood cells of hypertensive subjects

Several operationally defined adenosine triphosphatase (ATPase) activities were determined in vitro in red blood cell lysates of normotensive or hypertensive humans: Mg2+-ATPase, Na+,K+-ATPase, and Ca2+ pump ATPase, the latter in the calmodulin-activated and basal states. Basal Ca2+ pump ATPase was defined as the Ca2+-activated ATPase resistant to 10(-4) M trifluoperazine. Subjects were part of a double-blind study in which treatment was divided into several phases: baseline (4 weeks), placebo or calcium (1 g elemental calcium/day, 8 weeks), placebo washout (4 weeks), placebo or calcium (1 g elemental calcium/day, 8 weeks). Irrespective of the phase of treatment, the basal Ca2+ pump ATPase activity in red blood cell lysates of 36 hypertensive subjects was significantly less than that in lysates from 18 normotensive subjects. Other ATPase activities did not differ significantly, although all ATPases tended to be decreased in hypertension. The data are consistent with previous reports of altered membrane Ca2+ binding and transport in hypertension, but the precise changes are not elucidated.

Public acceptability of nudging and taxing to reduce consumption of alcohol, tobacco, and food: A population-based survey experiment

There is growing evidence for the effectiveness of choice architecture or 'nudge' interventions to change a range of behaviours including the consumption of alcohol, tobacco and food. Public acceptability is key to implementing these and other interventions. However, few studies have assessed public acceptability of these interventions, including the extent to which acceptability varies with the type of intervention, the target behaviour and with evidence of intervention effectiveness. These were assessed in an online study using a between-participants full factorial design with three factors: Policy (availability vs size vs labelling vs tax) x Behaviour (alcohol consumption vs tobacco use vs high-calorie snack food consumption) x Evidence communication (no message vs assertion of policy effectiveness vs assertion and quantification of policy effectiveness [e.g., a 10% change in behaviour]). Participants (N = 7058) were randomly allocated to one of the 36 groups. The primary outcome was acceptability of the policy. Acceptability differed across policy, behaviour and evidence communication (all ps < .001). Labelling was the most acceptable policy (supported by 78%) and Availability the least (47%). Tobacco use was the most acceptable behaviour to be targeted by policies (73%) compared with policies targeting Alcohol (55%) and Food (54%). Relative to the control group (60%), asserting evidence of effectiveness increased acceptability (63%); adding a quantification to this assertion did not significantly increase this further (65%). Public acceptability for nudges and taxes to improve population health varies with the behaviour targeted and the type of intervention but is generally favourable. Communicating that these policies are effective can increase support by a small but significant amount, suggesting that highlighting effectiveness could contribute to mobilising public demand for policies. While uncertainty remains about the strength of public support needed, this may help overcome political inertia and enable action on behaviours that damage population and planetary health.

Defective thyroid hormone action in fibroblasts cultured from subjects with the syndrome of resistance to thyroid hormones

Two preadolescent girls and their mother with the syndrome of central and peripheral resistance to thyroid hormones are reported. The sisters had goiters, high radioiodine uptakes, high plasma levels of thyroid hormones, normal TSH levels, and brisk increases in TSH after TRH administration, but had no clinical evidence of thyrotoxicosis. The mother, who had undergone partial thyroidectomy and radioiodine therapy, presented with mild hypothyroid symptoms, normal thyroid hormone levels, and a high TSH level. On T4 treatment, her TSH fell toward normal, and thyroid levels became elevated without thyrotoxic symptoms. Special studies were performed with cultured skin fibroblasts. T3 stimulated low density lipoprotein receptor activity in cells from normal subjects, but failed to do so in fibroblasts form the three patients, indicating that their fibroblasts had a defective response to T3. However, after incubation of fibroblasts with labeled T3, no abnormalities in the binding capacity or affinity of nuclei were observed. These findings suggest that in this family, the thyroid hormone resistance demonstrable in vivo and in vitro results from a cellular defect at a site other than at the nuclear binding site.

Sudden death of a volunteer

A volunteer participating in a study of eproxindine, a new antiarrhythmic agent, had a sudden cardiorespiratory arrest and died. Subsequently it became known that he had received a depot injection of flupenthixol on the day before his death; an interaction between these two drugs seems likely. This incident illustrates that it is impossible to guarantee absolute safety in volunteer studies if details of medical history are withheld.

Adjunctive arteriovenous fistula with tibial and peroneal reconstruction for limb salvage

Arteriovenous fistulas were constructed as an adjunct to femoral peroneal and tibial bypasses in 13 patients threatened by imminent limb amputation. Previous attempts at conventional vascular reconstructive procedures had failed in nine patients. Deficient or absent pedal arches were noted in all patients, as were poor quality or small crural arteries. Graft patency was achieved in 11 cases and limb salvage in 10. There was no mortality. A steal phenomenon occurred in one patient and was successfully treated by secondary popliteal vein ligation. These preliminary results clearly indicate that an adjunctive arteriovenous fistula can maintain patency in a femoral tibial or peroneal bypass graft while preserving flow into the markedly diseased distal circulation.

Hostility, hopelessness and deliberate self-harm: a prospective follow-up study

Sixty-one consecutive patients who presented following an episode of deliberate self-harm (DSH) were assessed on a number of variables, including measures of hopelessness and hostility. Attempts were made to follow all of the patients. Those who were known to have had a further episode of DSH had significantly higher levels of hopelessness and intropunitive hostility after the index episode than those who did not repeat. The question of vulnerability to DSH is discussed as well as the possibility of using measures of hopelessness and intropunitive hostility to identify those at greater risk of repetition.

Two novel endogenous digoxin-like immunoreactive substances isolated from human plasma ultrafiltrate

Two digoxin-like immunoreactive substances (DLIS 1 and DLIS-2) were isolated from human plasma by ultrafiltration, alkaline solvent extraction, and HPLC. Both inhibit canine Na, K-ATPase and cross-react with anti-digoxin antibodies. Their UV spectra are similar, with absorption peaks at 190 and 220 nm. FAB mass spectral analysis of both compounds yield a single dominant (M+H)+ component at m/z 532 otherwise, the fragmentation patterns are slightly different. The spectral data are consistent with the postulate that these compounds are related. Their identity as the natriuretic hormone is being investigated.

Mindfulness based cognitive therapy for youth with inflammatory bowel disease and depression - Findings from a pilot randomised controlled trial

BACKGROUND

Mindfulness-based cognitive therapy (MBCT) is a promising adjunctive treatment for adolescents and young adults (AYAs) with Inflammatory Bowel Disease (IBD) and comorbid depression.

OBJECTIVES

This pilot randomised controlled trial (RCT) aimed to evaluate feasibility and efficacy of an adapted MBCT program for AYA, aged 16-29, with IBD.

METHODS

Sixty-four AYAs were randomly allocated to MBCT (n = 33) or treatment as usual (TAU) (n = 31). Primary outcome measure was the depression score on Depression, Anxiety and Stress Scale. Secondary outcomes included anxiety, stress, IBD-related quality of life, coping, mindfulness, post-traumatic growth, medication adherence, IBD activity, inflammatory markers, microbiome characteristics and brain functional connectivity.

RESULTS

Study recruitment rate was 75%, retention rate 70%, and session attendance 92%. Intention to treat analyses revealed that, compared to TAU group, MBCT group had significantly lower depression (∆ = -6.0; 95%CI = -10.8 to -1.2; P = 0.015) and stress (∆ = -5.1; 95%CI = -10.1 to -0.0; P = 0.049), higher active coping (∆ = 1.0;95%CI = 0.1-1.9; P = 0.022), and total mindfulness scores (∆ = 10.9;95%CI = 1.1-20.8; P = 0.030) at 8 weeks (post-therapy), and improved coping by positive reframing (∆ = 1.1;95%CI = 0.0-2.2; P = 0.043) and planning (∆ = 0.9;95%CI = 0.0-1.9; P = 0.045), mindful awareness (∆ = 5.2.;95%CI = 2.0-8.5; P = 0.002) and total mindfulness scores (∆ = 10.8.;95%CI = 0.4-21.1; P = 0.042) at 20 weeks. On per protocol analysis, MBCT group had significantly lower depression (∆ = -6.3; 95%CI = -11.4 to -1.2; P = 0.015), stress (∆ = -6.0; 95%CI = -11.2 to -0.5; P = 0.032), increased active coping (∆ = 0.9;95%CI = 0-1.7; P = 0.05) at 8 weeks, and mindful awareness (∆ = 5.4; 95%CI = 2.1-8.6; P = 0.001) at 20 weeks.

CONCLUSION

In AYAs with IBD, MBCT is feasible and beneficial in improving depression, stress, mindfulness and adaptive coping. It holds promise as an important component of integrated IBD care. Trial registration number ACTRN12617000876392, U1111-1197-7370; Pre-results.

Citrate anticoagulation during in vivo simulation of slow hemofiltration

Citrate anticoagulation has been used as an alternative to heparin for hemodialysis in high-risk patients; however, its use in hemofiltration has not been well studied. We examined citrate in 6 patients placed on slow hemofiltration for up to 6 h duration. During the experiments, the systemic citrate level increased from a baseline average of 0.15 to 0.55 mmol/l, and then decreased to 0.27 mmol/l. The citrate was freely filtered. The systemic total and ionized calcium decreased very slightly and no untoward effects were noted. Anticoagulation was successful. This preliminary study suggests that citrate anticoagulation can be used in slow hemofiltration.

Major birth defects in very low birth weight infants in the Vermont Oxford Network

OBJECTIVE

To study the frequency and types of major birth defects in very low birth weight (VLBW) infants and their impact on mortality and resource use.

STUDY DESIGN

Analysis of data from the Vermont Oxford Network Database from 1994 and 1995 on infants with birth weights of 501 to 1500 g. Major birth defects were reported from a list of 40 defined major defects or if they were considered lethal or life-threatening. Mortality and length of stay were determined.

RESULTS

Major birth defects were present in 823 (4.3%) of 19,228 VLBW infants from 147 hospitals. The most common categories were chromosomal anomalies (20%); named syndromes, sequences, and associations (19%); and gastrointestinal (14%), cardiovascular (11%), and nervous system (10%) anomalies. Infants with major birth defects had a higher mortality rate (58% vs 13%, P <.001) and a higher rate of major surgery (29% vs 5%, P <.001) than infants without such defects. Infants with major birth defects accounted for 16.3% of deaths and 18.9% of major surgical procedures but only for 2.9% of total hospital days.

CONCLUSIONS

Major birth defects accounted for 16% of all deaths in VLBW infants. However, they accounted for a low proportion of total hospital days.

Transoesophageal ultrasound and computer tomographic assessment of the equine cricoarytenoid dorsalis muscle: Relationship between muscle geometry and exercising laryngeal function

REASONS FOR PERFORMING STUDY

Early detection of recurrent laryngeal neuropathy (RLN) is of considerable interest to the equine industry.

OBJECTIVES

To describe two imaging modalities, transoesophageal ultrasound (TEU) and computed tomography (CT) with multiplanar reconstruction to assess laryngeal muscle geometry, and determine the relationship between cricoarytenoid dorsalis (CAD) geometry and function.

STUDY DESIGN

Two-phase study evaluating CAD geometry in experimental horses and horses with naturally occurring RLN.

METHODS

Equine CAD muscle volume was determined from CT scan sets using volumetric reconstruction with LiveWire. The midbody and caudal dorsal-ventral thickness of the CAD muscle was determined using a TEU in the same horses; and in horses with a range of severity of RLN (n = 112).

RESULTS

Transoesophageal ultrasound was able to readily image the CAD muscles and lower left:right CAD thickness ratios were observed with increasing disease severity. Computed tomography based muscle volume correlated very closely with ex vivo muscle volume (R² = 0.77).

CONCLUSIONS

Computed tomography reconstruction can accurately determine intrinsic laryngeal muscle geometry. A relationship between TEU measurements of CAD geometry and laryngeal function was established. These imaging techniques could be used to track the response of the CAD muscle to restorative surgical treatments such as nerve muscle pedicle graft, nerve anastomosis and functional electrical stimulation.

Interaction of antimicrobial agents with human peripheral blood leucocytes: uptake and intracellular localization of certain sulphonamides and trimethoprims

The uptake of sulphamethoxazole, sulphadiazine, sulphamerazine, sulphanilamide, trimethoprim and brodimoprim by human peripheral blood leucocytes, has been investigated. High performance liquid chromatography (HPLC) was used to assay drug concentrations before and after incubation with leucocyte suspensions. Using radiolabelled material the intracellular localization of two of these compounds was also determined. The results indicated that all the investigated drugs were taken up by leucocytes. Differential studies demonstrated that mononuclear cells accumulated higher drug concentrations (0.13-0.55 microgram/10(7) cells), than resting neutrophils (0.02-0.26 microgram/10(7) cells) with the exception of sulphanilamide, which was taken up to a greater extent by neutrophils (0.75 microgram/10(7) cells). During neutrophil phagocytosis intracellular levels of all the drugs except brodimoprim increased from 3 to 130-fold as compared to resting neutrophils. The uptake of 14C-sulphanilamide and 14C-trimethoprim, in neutrophils and mononuclear blood cells, as assessed by measurement of the cell-associated radioactivity, correlated well with that determined by the HPLC procedure. In the intracellular localization studies 14C-sulphanilamide and 14C-trimethoprim exhibited similar distribution profiles. In neutrophils, 35-40% of radiolabelled drug was located in both the microsome and cytosol fractions whereas in peripheral blood mononuclear cells 40-60% was found in the cytosol and 10-20% in the microsome fraction. The results of this study suggest that, following activation, leucocytes may actively transport these drugs and release them locally at sites of infection. The ability of neutrophils to further concentrate the drugs during phagocytosis may result in reduced survival time of some ingested bacteria. These concepts may be important in designing treatment stratagems for intracellular pathogens.

Mass spectrometry studies of a novel digoxin-like substance (DLIS-2) isolated from human plasma ultrafiltrate

Two unique low molecular weight (531) compounds with both digoxin-like immunoreactivity and Na, K-ATPase inhibitory properties have been isolated from human plasma. One of these, digoxin-like substance 2, (DLIS-2), was studied by fast atom bombardment mass spectrometry and collisionally activated dissociation mass spectrometry/mass spectrometry. The fragment patterns were interpreted as being derived from a lysophosphatidyl serine containing a novel 19:4 fatty acid side chain. The molecular formula C25H42O9NP is consistent with these observations.