Prospective analysis of a surgical algorithm to achieve ventilator weaning in cervical tetraplegia

Objectives: Chronic ventilator dependency in cervical tetraplegia is associated with substantial morbidity. When non-invasive weaning methods have failed the primary surgical treatment is diaphragm pacing. Phrenic nerve integrity and diaphragm motor units are requirements for effective pacing but may need to be restored for successful weaning. A surgical algorithm that includes: 1. Diaphragm pacing, 2. Phrenic nerve reconstruction, and 3. Diaphragm muscle replacement, may provide the capability of reducing or reversing ventilator dependency in virtually all cervical tetraplegics.Design: Prospective case series.Setting: A university-based hospital from 2015 to 2019.Participants: Ten patients with ventilator-dependent cervical tetraplegia.Interventions: I. Pacemaker alone, II. Pacemaker + phrenic nerve reconstruction, or III. Pacemaker + diaphragm muscle replacement.Outcome measures: Time from surgery to observed reduction in ventilator requirements (↓VR), ventilatory needs as of most recent follow-up [no change (NC), partial weaning (PW, 1-12 h/day), or complete weaning (CW, >12 h/day)], and complications.Results: Both patients in Group I achieved CW at 6-month follow-up. Two patients in Group II achieved CW, and in another two patients PW was achieved, at 1.5-2-year follow-up. The remaining two patients are NC at 6 and 8-month follow-up, respectively. In group III, both patients achieved PW at 2-year follow-up. Complications included mucous plugging (n = 1) and pacemaker malfunction requiring revision (n = 3).Conclusion: Although more investigation is necessary, phrenic nerve reconstruction or diaphragm muscle replacement performed (when indicated) with pacemaker implantation may allow virtually all ventilator-dependent cervical tetraplegics to partially or completely wean.

Phrenic Nerve Reconstruction for Effective Surgical Treatment of Diaphragmatic Paralysis

ABSTRACT

Diaphragmatic paralysis due to phrenic nerve injury may cause orthopnea, exertional dyspnea, and sleep-disordered breathing. Phrenic nerve reconstruction may relieve symptoms and improve respiratory function. A retrospective review of 400 consecutive patients undergoing phrenic nerve reconstruction for diaphragmatic paralysis at 2 tertiary treatment centers was performed between 2007 and 2019. Symptomatic patients were identified, and the diagnosis was confirmed on radiographic evaluations. Assessment parameters included pulmonary spirometry (forced expiratory volume in 1 second and FVC), maximal inspiratory pressure, compound muscle action potentials, diaphragm thickness, chest fluoroscopy, and Short Form 36 Health Survey Questionnaire (SF-36) survey. There were 81 females and 319 males with an average age of 54 years (range, 19-79 years). The mean duration from diagnosis to surgery was 29 months (range, 1-320 months). The most common etiologies were acute or chronic injury (29%), interscalene nerve block (17%), and cardiothoracic surgery (15%). The mean improvements in forced expiratory volume in 1 second and FVC at 1 year were 10% (P < 0.01) and 8% (P < 0.05), respectively. At 2-year follow-up, the corresponding values were 22% (P < 0.05) and 18% (P < 0.05), respectively. Improvement on chest fluoroscopy was demonstrated in 63% and 71% of patients at 1 and 2-year follow-up, respectively. There was a 20% (P < 0.01) improvement in maximal inspiratory pressure, and compound muscle action potentials increased by 82% (P < 0.001). Diaphragm thickness demonstrated a 27% (P < 0.01) increase, and SF-36 revealed a 59% (P < 0.001) improvement in physical functioning. Symptomatic diaphragmatic paralysis should be considered for surgical treatment. Phrenic nerve reconstruction can achieve symptomatic relief and improve respiratory function. Increasing spirometry and improvements on Sniff from 1 to 2 years support incremental recovery with longer follow-up.

5-year results of accelerated partial breast irradiation (APBI) with SBRT (stereotactic body radiation therapy) and exactrac adaptive gating (Novalis®) for very early breast cancer patients: was it all worth it?

PURPOSE

To explore the feasibility of image-guided and respiratory-gated Stereotactic Body Radiation Therapy (SBRT) for Accelerated Partial Breast Irradiation (APBI) in patients with very early breast cancer.

MATERIAL AND METHODS

Selected patients with early breast carcinoma after breast-conserving surgery were enrolled in this phase II trial. A fiducial marker was percutaneously placed close to surgical bed and five external fiducials were set on the skin. A CT scan for planning was acquired at free breathing. The treatment was planned and DVH were assessed according to international recommendations. Prescription dose was 30 Gy in five consecutive fractions of 6 Gy. A 6MV monoenergetic LINAC (linear accelerator) that combines stereoscopic X-ray imaging system and ExacTrac Adaptive Gating technique was used. PTV (planning target volume) intrafraction motion was controlled and PTV was irradiated in a selected gated area of the respiratory cycle. Shifts for a correct, gated set-up were calculated and automatically applied.

RESULTS

Between April 2013 and October 2015, a total of 23 patients were included. The median tumor size was 12 mm. The mean PTV volume was 114 cc. The mean ipsilateral lung V9 Gy was 2.2% and for left-sided breast cancers, the volume of the heart receiving 1.5 Gy was 11.5%. Maximum skin dose was 30.8 Gy. Acute toxicity was grade1 in all the patients and 100% experienced excellent/good breast cosmesis outcomes. With a median follow-up of 66 months (range 8-99 months) local-relapse-free-survival reaches 100%. One patient developed a second breast cancer outside the treated quadrant after 25.1 months.

CONCLUSION

APBI with SBRT and ExacTrac Adaptive Gating System was feasible. The acute and late toxicities were almost null and cosmesis was excellent. We also found that the margins of 5 mm applied from CTV to PTV were sufficient to compensate for geometric uncertainties.

Treatment for bilateral diaphragmatic dysfunction using phrenic nerve reconstruction and diaphragm pacemakers

OBJECTIVES

Bilateral diaphragmatic dysfunction results in severe dyspnoea, usually requiring oxygen therapy and nocturnal ventilatory support. Although treatment options are limited, phrenic nerve reconstruction (PR) offers the opportunity to restore functional activity. This study aims to evaluate combination treatment with PR and placement of a diaphragm pacemaker (DP) compared to DP placement alone in patients with bilateral diaphragmatic dysfunction.

METHODS

Patients with bilateral diaphragmatic dysfunction were prospectively enrolled in the following treatment algorithm: Unilateral PR was performed on the more severely impacted side with bilateral DP implantation. Motor amplitudes, ultrasound measurements of diaphragm thickness, maximal inspiratory pressure, forced expiratory volume, forced vital capacity and subjective patient-reported outcomes were obtained for retrospective analysis following completion of the prospective database.

RESULTS

Fourteen male patients with bilateral diaphragmatic dysfunction confirmed on chest fluoroscopy and electrodiagnostic testing were included. All 14 patients required nocturnal ventilator support, and 8/14 (57.1%) were oxygen-dependent. All patients reported subjective improvement, and all 8 oxygen-dependent patients were able to discontinue oxygen therapy following treatment. Improvements in maximal inspiratory pressure, forced vital capacity and forced expiratory volume were 68%, 47% and 53%, respectively. There was an average improvement of 180% in motor amplitude and a 50% increase in muscle thickness. Comparison of motor amplitude changes revealed significantly greater functional recovery on the PR + DP side.

CONCLUSIONS

PR and simultaneous implantation of a DP may restore functional activity and alleviate symptoms in patients with bilateral diaphragmatic dysfunction. PR plus diaphragm pacing appear to result in greater functional muscle recovery than pacing alone.

Comparison of Phasix, polypropylene, and primary closure of the abdominal donor site after bilateral free flap breast reconstruction: Long-term evaluation of abdominal hernia and bulge formation

BACKGROUND

Abdominal free flap harvest for breast reconstruction may result in significant morbidity in terms of hernias and bulges. Reinforcement of the donor site with mesh has been recommended to minimize the risk of hernias and bulges, but no studies exist evaluating the optimal type of mesh. Polypropylene has traditionally been used but the development of Phasix restorable mesh may be a reasonable alternative. Here, we compared the use of Phasix to polypropylene and primary closure and hypothesize that the former has lower rates of abdominal morbidity in the long term.

PATIENTS AND METHODS

A retrospective review of all patients undergoing bilateral free flap breast reconstruction from the abdomen was performed while patients with pedicle flaps or alternative donor sites were excluded. Patient demographics, medical/surgical history, cancer treatments, and flap type were analyzed. All patients were monitored for a minimum of 2 years for early donor site complications as well as hernia/bulges.

RESULTS

Sixty-six consecutive patients were included (40 patients with Phasix, 20 patients with polypropylene, and 6 patients with primary closure). Use of Phasix mesh resulted in higher initial operative costs ($2,750 vs. $72 vs. $0). Two patients with polypropylene mesh and one patient undergoing primary closure developed an abdominal bulge in an average follow-up of 25.2 months (11.5% vs. 0%, p = .04).

CONCLUSIONS

Mesh placement for abdominal wall reinforcement after bilateral free flap breast reconstruction minimizes the risk of hernias and bulges. Although Phasix results in increased initial costs, abdominal morbidity is significantly decreased after follow-up beyond 2 years.

Microneurosurgical treatment options in peripheral nerve compression syndromes after chemotherapy and radiation treatment

Chemotherapy-induced peripheral neuropathy and radiation-induced brachial plexopathy are extremely debilitating conditions which can occur after treatment of malignancy. Unfortunately, the diagnosis can be elusive, and this dilemma is further compounded by the lack of efficacious therapeutics to prevent the onset of neurotoxicity before initiating chemotherapy or radiation or to treat these sequelae after treatment. However, microsurgical nerve decompression can provide these patients with a viable option to treat this complication.

Thermodynamics of CuPt nanoalloys

The control of structural and chemical transitions in bimetallic nanoalloys at finite temperatures is one of the challenges for their use in advanced applications. Comparing Nested Sampling and Molecular Dynamics simulations, we investigate the phase changes of CuPt nanoalloys with the aim to elucidate the role of kinetic effects during their solidification and melting processes. We find that the quasi-thermodynamic limit for the nucleation of (CuPt)₃₀₉ is 965 ± 10 K, but its prediction is increasingly underestimated when the system is cooled faster than 10⁹ K/s. The solidified nanoparticles, classified following a novel tool based on Steinhardt parameters and the relative orientation of characteristic atomic environments, are then heated back to their liquid phase. We demonstrate the kinetic origin of the hysteresis in the caloric curve as (i) it closes for rates slower than 10⁸ K/s, with a phase change temperature of 970 K ± 25 K, in very good agreement with its quasi-thermodynamic limit; (ii) the process happens simultaneously in the inner and outer layers; (iii) an onion-shell chemical order - Cu-rich surface, Pt-rich sub-surface, and mixed core - is always preserved.

Burn scar regeneration with the "SUFA" (Subcision and Fat Grafting) technique. A prospective clinical study

Background

Treatment of burn scars with traditional surgical techniques is challenging due to recurrent contractures. Fat grafting has been previously used in small clinical series and results are often biased by lack of scientific validating methods. Fat grafting in clinical practice is often evaluated for its filler properties and rarely scientifically validated for its potential in dermal regeneration. Animal studies have shown dermal regeneration with new deposition and reorientation of the collagen fiber. Our study aims to apply the validity of in vitro studies to clinical practice.

Methods

Our study prospectively evaluated outcomes in 12 patients treated with the “SUFA” technique (Subcision and Fat Grafting) for debilitating contracted burns scars limiting range of motion. Results were evaluated clinically with the Vancouver scale and by range of motion at 1, 3, 6 and 12 months. Dermal regeneration was evaluated by looking at dermis thickening using high definition ultrasound and scar remodeling looking at reorientation and new deposition of collagen fibers with hematoxylin-eosin histology and monoclonal antibodies against collagen type 1 and 3.

Results

Statistically significant clinical improvements in range of motion of the affected joints was observed (P<0.05). Fat reabsorption occurred with a mean of 40%. Thickening of dermis and redistribution and reorientation of the collagen fibers within the dermis was also demonstrated.

Conclusions

Our results present the first clinical scientific evidence of dermal regeneration in fat grafting. Using monoclonal antibodies and high definition ultrasounds, we demonstrate the first evidence of dermis regeneration in a clinical scenario.

Melting of large Pt@MgO(1 0 0) icosahedra

On the basis of ab initio calculations, we present a new parametrisation of the Vervisch-Mottet-Goniakowski (VMG) potential (Vervisch et al 2002 Phys. Rev. B 24 245411) for modelling the oxide-metal interaction. Applying this model to mimic the finite temperature behaviour of large platinum icosahedra deposited on the pristine MgO(1 0 0), we find the nanoparticle undergoes two solid-solid transitions. At 650 K the 'squarisation' of the interface layer, while a full reshaping towards a fcc architecture takes place above 950 K. In between, a quite long-lived intermediate state with a (1 0 0) interface but with an icosahedral cap is observed. Our approach reproduces experimental observations, including wetting behaviour and the lack of surface diffusion.

Reasons for and consequences of vitamin K antagonist discontinuation in very elderly patients with non-valvular atrial fibrillation

Essentials Anticoagulation in the elderly is still a challenge and suspension of warfarin is common. This is an observational study reporting reasons and consequences of warfarin suspension. Vascular disease, age, time in therapeutic range, and bleedings are associated with suspension. After suspension for bleeding or frailty, patients remain at high-risk of death or complications.

SUMMARY

Background Anticoagulation in elderly patients with non-valvular atrial fibrillation (NVAF) is still a challenge, and discontinuation of warfarin is common. The aim of this study was to analyze the aspects related to warfarin discontinuation in a real-world population. Methods This was an observational cohort study on very elderly NVAF patients naive to warfarin therapy (VENPAF). The included subjects were aged at least 80 years, and started using warfarin after a diagnosis of NVAF. Warfarin discontinuation was assessed, and the reason reported for discontinuation, the person who decided to stop treatment, subsequent antithrombotic therapy and mortality, ischemic and bleeding events were collected. Results Over a period of 5 years, warfarin was discontinued in 148 of 798 patients. Despite similar CHA2 DS2 -VASc scores, the frequencies of thromboembolic and major bleeding events were significantly higher (P = 0.01 and P = 0.001, respectively) and the time in therapeutic range (TTR) was significantly lower (P < 0.001) in patients who discontinued warfarin. Independent risk factors for warfarin discontinuation were vascular disease (hazard ratio [HR] 2.5, P < 0.001), age ≥ 85 years (HR 1.4, P = 0.04), TTR < 60% (HR 1.8, P = 0.001), and bleeding events (HR 2.3, P < 0.001). The main reasons for warfarin discontinuation were physician-perceived frailty or low life-expectancy (45.9%), bleeding complications (19.6%), and sinus rhythm restoration (16.9%). Event and death rates were very high, especially in frail patients and in those with bleeding complications. Conclusions Warfarin discontinuation is frequent in very elderly patients, and is associated with increased risks of death and adverse events. Identification of elderly patients who are at high risk of bleeding and the poor quality of anticoagulation during warfarin are still unsolved clinical problems.

[Prophylaxis of group B streptococcal infections in the birth centers of Emilia Romagna]

OBJECTIVES

In the last decade several guidelines for prevention of neonatal group B streptococcal invasive disease have been published, mainly based on administration of intrapartum antibiotics. The spread of such recommendations yielded a reduction of the early-onset disease. The aim of the study was to investigate the practices for prophylaxis of neonatal infection in our region during the 2000 and to standardize them according to the new available evidence.

METHODS

We conducted a multicenter study in Emilia Romagna, sending by mail a detailed questionnaire to the 28 birth centers of our region.

RESULTS

Fifteen centers answered to the questionnaire. The practices were often differing from the recommendations of scientific societies. The most sensitive methods to identify colonized women were not widely used. Colonized infants were frequently treated with antibiotics and discharged later from the nursery. The incidence of neonatal invasive diseases was low, but most centers did not regularly collect a blood culture before antibiotic treatment is started.

CONCLUSIONS

Repeated meetings among centers promoted the diffusion of information, the implementation of a shared protocol and the spread of the practices. The results of such meetings will be evalued in the next months.

A genetic model provides evidence that the receptor for atrial natriuretic peptide (guanylyl cyclase-A) inhibits cardiac ventricular myocyte hypertrophy

Guanylyl cyclase-A (NPR-A; GC-A) is the major and possibly the only receptor for atrial natriuretic peptide (ANP) or B-type natriuretic peptide. Although mice deficient in GC-A display an elevated blood pressure, the resultant cardiac hypertrophy is much greater than in other mouse models of hypertension. Here we overproduce GC-A in the cardiac myocytes of wild-type or GC-A null animals. Introduction of the GC-A transgene did not alter blood pressure or heart rate as a function of genotype. Cardiac myocyte size was larger (approximately 20%) in GC-A null than in wild-type animals. However, introduction of the GC-A transgene reduced cardiac myocyte size in both wild-type and null mice. Coincident with the reduction in myocyte size, both ANP mRNA and ANP content were significantly reduced by overexpression of GC-A, and this reduction was independent of genotype. This genetic model, therefore, separates a regulation of cardiac myocyte size by blood pressure from local regulation by a GC-mediated pathway.

Metabolic and respiratory effects of theophylline in the preterm infant

BACKGROUND

Methylxanthines are often administered to preterm infants for the treatment of apnoea.

AIMS

To study the effects of theophylline on energy metabolism, physical activity, and lung mechanics in preterm infants.

METHODS

Indirect calorimetry was performed for six hours before and after administration of a bolus of theophylline (5 mg/kg) in 18 preterm infants while physical activity was recorded with a video camera. Lung mechanics measurements were performed at baseline and 12 and 24 hours after theophylline treatment.

RESULTS

Theophylline increased mean (SEM) energy expenditure by 15 (5) kJ/kg/day and augmented carbohydrate utilisation from 6.8 to 8.0 g/kg/day, but fat oxidation was unchanged. After theophylline treatment, preterm infants had faster respiration, lower transcutaneous CO2, and improved static respiratory compliance without increased physical activity.

CONCLUSIONS

A bolus of 5 mg/kg theophylline increased energy expenditure independently of physical activity, increased carbohydrate utilisation, and improved respiratory compliance. The increased energy expenditure could be detrimental to the growth of the preterm infant.

Factors affecting the work of an occupational health nurse

Society, economies, work-life and work are undergoing changes that will have global impact on occupational health services (OHS) and the work of occupational health nurses (OHNs) during the next 5-10 years. These changes will bring new challenges to both occupational health services and representatives of specialist groups within those services. The changes will require new ways of working, work methods, performance monitoring, and evaluation of impacts. These developments will also call for changes in the education of occupational health nurses.

Genetics and molecular biology of the GHRH-GH-IGF-I axis

In this paper, the genetics and molecular biology of the GHRH-GH-IGF-I (Growth Hormone Releasing hormone-Growth Hormone-Insulin like Growth Factor I) axis involved in the pathogenesis of short stature are reviewed. Short stature associated with GH deficiency is estimated to occur in about 1/4000-10,000 live births; 3-30% of cases affect first-degree relatives, suggesting a genetic aetiology. Identification of such molecular defects is very recent and dependent on new findings on the physiology of GHRH-GH-IGF-I axis: for example the pituitary-specific transcription factors and their mutations have only been described in the last few years. The epidemiological importance of the identified molecular defect depends on the level of the axis involved, but the prevalence of some of these genetic defects is probably underestimated. Time will tell what the practical relevance of these findings is and what the clinical features of the new mutations are; we will probably learn something more about the GHRH-GH-IGF-I axis: to date, no mutations have been reported regarding the GHRH gene or the IGF-I receptor.

Ethical issues among Finnish occupational physicians and nurses

A postal survey was conducted among 200 Finnish occupational physicians and nurses on their ethical values and problems. Both groups considered 'expertise' and 'confidentiality' as the most important core values of occupational health services (OHS) corresponding with newly published national ethical guidelines for occupational physicians and nurses in Finland. Nearly all respondents had encountered ethically problematic situations in their work, but ethical problems with gene testing in the near future were not considered likely to occur. Only 41% of the nurses and 36% of the physicians had received some training in the ethics of OHS, and 76% of all respondents never used available ethical guidelines. According to the results, even if ethics play a vital role in OHS, the ability to critically evaluate one's own performance seems quite limited. This creates a need for further training and more practicable national guidelines.

Glucose turnover and gluconeogenesis in human pregnancy

The rate of appearance (Ra) of glucose in plasma and the contribution of gluconeogenesis were quantified in normal pregnant women early ( approximately 10 wk) and late ( approximately 34 wk) in gestation. Their data were compared with those of normal nonpregnant women. Glucose Ra was measured using the [U-13C]glucose tracer dilution method. Gluconeogenesis was quantified by the appearance of 2H on carbon 5 and 6 of glucose after deuterium labeling of body water pool. Weight-specific glucose Ra was unchanged during pregnancy (nonpregnant, 1.89+/-0.24; first trimester, 2.05+/-0.21; and third trimester 2.17+/-0.28 mg/kg.min, mean+/-SD), while total glucose Ra was significantly increased (early, 133.5+/-7.2; late, 162.6+/-16.4 mg/min; P = 0.005). The fractional contribution of gluconeogenesis via pyruvate measured by 2H enrichment on C-6 of glucose (45-61%), and of total gluconeogenesis quantified from 2H enrichment on C-5 of glucose (i.e. , including glycerol [68-85%]) was not significantly different between pregnant and nonpregnant women. Inasmuch as total glucose Ra was significantly increased, total gluconeogenesis was also increased in pregnancy (early pregnancy, 94.7+/-15.9 mg/min; late pregnancy, 122.7+/-9.3 mg/min; P = 0.003). These data demonstrate the ability of the mother to adapt to the increasing fetal demands for glucose with advancing gestation. The mechanism for this unique quantitative adjustment to the fetal demands remains undefined.

Activation of N-methyl-D-aspartate receptors regulates basal electrical activity of oxytocin and vasopressin neurons in lactating rats

The control of suckling-induced bursting activity of oxytocin neurons and of phasic activity of vasopressin neurons by N-methyl-D-aspartate receptors was investigated in anaesthetized lactating rats. Receptor antagonist or agonist was applied in the vicinity of supraoptic neurons recorded extracellularly. The basal activity of oxytocin neurons was tonically decreased and increased by sustained application of the antagonist and agonist respectively. These effects occurred independently of the effectiveness of suckling to trigger the bursting pattern. When drugs were applied during an ongoing series of milk-ejection-related bursts, these changes were accompanied by parallel modifications in burst amplitude, but burst periodicity was unaffected. In rats failing to milk-eject, antagonist or agonist application did not facilitate the occurrence of bursts. Simultaneous recordings from oxytocin neurons in the contralateral supraoptic nucleus showed that neither their basal nor their bursting activity were affected, indicating the absence of cross-talk between nuclei during such application. The excitatory effect of N-methyl-D-aspartate differed from that induced in the same neurons by i.c.v. injection of oxytocin, which enhanced basal level of activity and burst amplitude, but also increased burst frequency. Furthermore, the distribution of interspike intervals indicated that N-methyl-D-aspartate, but not oxytocin, induced a regularization of the spike pattern. For vasopressin neurons, application of the receptor antagonist inhibited phasic activity by decreasing burst duration and increasing silences. Conversely, N-methyl-D-aspartate enhanced phasic activity, increasing both the duration of the active phases and the frequency of spikes during active phases. When applied to silent vasopressin neurons, N-methyl-D-aspartate induced a regular phasic activity. These results provide evidence that functional N-methyl-D-aspartate receptors regulate the excitability of both oxytocin and vasopressin neurons in lactating rats. These receptors play a paramount role in maintaining a certain level of basal activity which will favour appropriate discharge patterns, tonic for oxytocin neurons and phasic for vasopressin neurons. For oxytocin neurons, this sustained control by ambient glutamate influences the amplitude of bursts, but N-methyl-D-aspartate receptors are probably not involved in the generation of the bursting pattern.

Medium-chain triacylglycerols in formulas for preterm infants: effect on plasma lipids, circulating concentrations of medium-chain fatty acids, and essential fatty acids

Limited information is available on the metabolic fate of medium-chain triacylglycerols (triglycerides) after intestinal absorption and on their influence on essential fatty acid metabolism. We studied in preterm infants the effect of two infant formulas, one with a high (HMCT) and one with a low (LMCT) medium-chain triacylglycerol content, on plasma fatty acids. The HMCT formula contained 46 mol% 8:0 + 10:0 and the LMCT formula (4.8 mol% 8:0 + 10:0) had approximately twice the amount of long-chain saturated and monounsaturated fatty acids as the HMCT. Both formulas had similar contents of linoleic and linolenic acids. Plasma lipids and fatty acids were determined at birth and on day 24 of life in 20 infants fed the LMCT (n = 12) or HMCT (n = 8) formula. Significant amounts of medium-chain fatty acids were found in the systemic circulation of the infants fed the HMCT formula, mainly in plasma fatty acids and triacylglycerols. Despite striking dietary differences, palmitic and stearic acids were not different between groups, indicating de novo synthesis of long-chain fatty acids with the HMCT formula. Plasma phospholipid docosahexaenoic acid was significantly lower in the HMCT group than in the LMCT infants (1.38 +/- 0.07 compared with 1.73 +/- 0.07 mol%, P = 0.002). Our data indicate that a high MCT intake in preterm infants increases lipogenesis, and dietary nonessential fatty acids interfere with the metabolism of docosahexaenoic acid.

Glucose metabolism during fasting through human pregnancy: comparison of tracer method with respiratory calorimetry

Glucose turnover and glucose oxidation were quantified in six normal pregnant women serially throughout pregnancy, using [U-13C]glucose tracer in combination with open-circuit indirect respiratory calorimetry. Five normal nonpregnant women were studied for comparison. With advancing gestation and increase in maternal body weight, there was a proportionate increase in the rate of appearance (Ra) of glucose so that Ra expressed per kilogram body weight did not change from the first to third trimester. The tracer measured rate of glucose oxidation expressed per kilogram body weight also did not change significantly throughout pregnancy. Oxygen consumption (VO2) in pregnant subjects did not differ from that in nonpregnant subjects. However, the respiratory exchange ratio (RER) increased significantly during pregnancy (0.88 +/- 0.53 3rd trimester and 0.76 +/- 0.50 nonpregnant, P < 0.01). The estimated contribution of carbohydrate to VO2 measured by respiratory calorimetry was greater than that measured by the tracer method. This discrepancy became wider as the respiratory quotient increased in late pregnancy. These data suggest that maternal glucose metabolism adjusts throughout pregnancy to meet the increased demands of the conceptus. The discrepancy between tracer method and respiratory calorimetry was probably due to the contribution of (fetal) lipogenesis and (maternal) gluconeogenesis to RER.

Occupational health services in the Nordic countries

Occupational health services in the Nordic countries--Denmark, Finland, Iceland, Norway, and Sweden--started as initiatives of single industrial enterprises. Coverage of employees by voluntary occupational health services ranges from an estimated 23% of employees in Denmark to 93% of employees in Finland. Contents of OHS in the Nordic countries correspond mainly with the ILO Convention (161/85) on OHS. The services are primarily directed to preventing work related problems and achieving a better working environment. Employers are responsible for the total costs of occupational health services in all Nordic countries, but each nation has state reimbursement plans to help cover the costs. However, additional advantages in the subsidy system are needed to stimulate even the smaller enterprises to join the occupational health system.

Rheumatology algorithms for primary care physicians

Primary care physicians were trained on three rheumatology topics to assess the effectiveness of an educational strategy for continuing medical education. Algorithm training was shown to be at least as effective as that based on standard prose monographs. Both training groups improved their knowledge of patient management skills but there were no statistically significant differences between groups in the amount learned. When algorithms were used to design text materials, the designed texts required less study time than did the annotated clinical algorithms alone. That difference was significant for the shoulder pain materials (P less than 0.05) but not for the osteoporosis materials. The ratio of knowledge gained to study time was significantly higher for the algorithm group on the low back pain topic (P less than 0.05) but not for the other topics. Taped interview problems tests were studied as a method for assessing patient management skills related to problem-specific indicator conditions and were found to produce interrater reliability greater than 0.80 on five of the six tests.

Differential inhibition of mitogen induced T cell proliferation by 5-azacytidine and cytosine-arabinoside

The cytotoxic drugs 5-azacytidine and cytosine-arabinoside influence the enzymatic methylation of DNA in opposite ways (1,2). The in vitro effects of these two drugs on Con A induced proliferation of thymic and splenic rat lymphocytes were investigated. Cytosine-arabinoside was found to inhibit mitogen induced proliferation already at a concentration of 0.001 microM, whereas 5-azacytidine was inhibitory only above concentrations of 1 microM. A stimulation of mitogen induced T cell proliferation was consistently seen with 5-azacytidine, but not with cytosine-arabinoside, at concentrations lower than the cytotoxic concentration. The results show that 5-azacytidine and cytosine-arabinoside interfere with mitogen stimulated lymphocyte proliferation by different mechanisms and suggest that hypomethylated DNA plays a role in the proliferation of T cells.

T cell hyperreactivity in obese strain (OS) chickens. Different mechanisms operative in spleen and peripheral blood lymphocyte activation

The enhanced T cell reactivity (ConA hyperresponsiveness and IL 2 hypersecretion) of spleen lymphocytes of Obese strain (OS) chickens with spontaneous autoimmune thyroiditis has recently been shown to be due to a defect in macrophage-derived non-specific suppressor factors that regulate IL 2 secretion and IL 2-promoted T lymphoblast proliferation in normal healthy animals. In the present study, we present several lines of evidence that the increased T cell response of peripheral blood lymphocytes (PBL) of OS chickens is due to mechanisms entirely different from the described dysregulation of splenic T cells: 1) In contrast to the splenic macrophages, peripheral blood monocytes of OS animals are not deficient in the production of IL 2 antagonistic activity (IAA); 2) therefore, cocultivation of PBL from OS and Normal White Leghorn (NWL) chickens in communicating culture chambers did not abrogate the difference in Con A response as previously observed with spleen lymphocytes. 3) Immunofluorescence with a monoclonal antibody (INN CH 16) against the chicken IL 2 receptor revealed enhanced numbers of mitogen activatable T cells in OS PBL but not OS spleen lymphocytes. 4) After prolonged Con A stimulation of PBL, OS and NWL lymphoblasts did not differ from each other in functional aspects. In contrast to this, Con A lymphoblasts from OS spleens exhibited enhanced staining with INN CH 16 in parallel with an increased proliferative response to IL 2. Thus, the primary T cell dysfunction involved in the development of autoimmune disease in OS chickens is the result of at least two separate regulatory defects.