331 COVID-19 Mortality After Vascular Procedures During the Initial UK Surge: Moving Forward with Elective Vascular Work

Aim

Following the initial COVID-19 surge in the United Kingdom, there was a national incentive for elective vascular surgery to be restricted to clean sites in order to reduce perioperative cross infection and subsequent mortality. We assessed the risk of dying from perioperatively acquired COVID-19 during the peak of the London outbreak.

Method

43 consecutive patients who had vascular (n = 48) procedures in March and April 2020 at a regional hub serving five London hospitals were analysed. The patients were screened for COVID-19 in the 30-day postoperative period and the main outcome measure was mortality from COVID-19. A comparison was then made with patients who underwent minimally invasive procedures from our integrated interventional radiology department. Median follow-up was 41 days (IQR 8- 58 days).

Results

Three patients (7%) in the vascular group (median age 61 years, all diabetic, two male) died from COVID-19, all of whom tested positive postoperatively. Two others became positive but recovered. In comparison, two patients (2%) in the interventional radiology group died from COVID-19, however one was positive prior to their procedure.

Conclusions

Only urgent vascular cases should be performed during a COVID-19 surge, with elective work delayed or continued at clean sites. However, with growing waiting lists for elective surgery currently, further restrictions may not be a viable long-term solution. Resumption of care at hot sites should be considered, if resources allow for it and if safety measures can be implemented. The advantages of minimally invasive surgery may inherently reduce risk as well.

Stable, high yield expression of gp145 Env glycoprotein from HIV-1 in mammalian cells

The HIV-1 derived gp145 protein is being investigated by research groups as preclinical studies have shown high promise for this protein as a vaccine against HIV. However, one of the main challenges with manufacturing this promising protein has been ascribed to the low yield obtained in mammalian cell cultures. Significant improvements in gp145 production are needed to address this issue to test the gp145 protein as a potentially effective, safe, and affordable HIV vaccine. Here we describe the application of a novel expression technology to create GMP-grade CHO cell lines expressing approximately 50 μg/ml in non-optimized fed-batch culture, which is an order of magnitude higher than that obtained in existing processes. Top producing clones show a high degree of similarity in the glycosylation patterns of the purified protein to the reference standard. Conformational integrity and functionality was demonstrated via high-affinity binding to soluble CD4, using a panel of antibodies including VRC01, F105, Hk20, PG9 and 17b. In summary, we were able to generate CHO cell lines expressing HIV gp145 with significantly higher overall expression yields than currently accessible, and high product quality that could potentially be suitable for future studies assessing the efficacy and safety of gp145-based HIV vaccines.

STEP® vectors for rapid generation of stable transfected CHO cell pools and clones with high expression levels and product quality homogeneity of difficult-to-express proteins

Many proteins produced in CHO cells need evaluation for their clinical and commercial potential. Traditional methods based on stable clone generation are slow and unsuitable for screening larger numbers of proteins, while transient expression technologies are fast but unpredictable regarding product quality and lacking an optional path to subcloning. The STEP® vector technology introduced here combines the best properties of both methods. STEP® vectors contain a strong transcriptional cassette driving expression of a bicistronic mRNA. The gene-of-interest (GOI) is cloned upstream of a functionally impaired zeocin resistance gene (FI-Zeo) whose translation is coupled to that of the GOI through an IRES. Stable transfected cells surviving zeocin selection produce high levels of FI-Zeo and thus, high levels of the GOI-encoded protein. By using different spacers, the translational coupling efficiency and selection strength can be controlled allowing maximization of expression of any GOI. Production of laronidase and factor VII (FVII) is presented as examples of unrelated, difficult-to-express (DTE) proteins. First step is rapid generation of transfected pools with the STEP® vectors. All high expressing surviving pools showed high product quality homogeneity as did monoclonal cell lines obtained from the top pools. Up to 500 μg/mL laronidase was obtained with virtually identical glycosylation profile as reference product. For FVII, cell specific productivity of 0.45 pg/cell/day with 50 IU/μg protein matched highest reported levels of reference product even before process development. Taken together, STEP® vector technology is ideally suited for rapid, small to large-scale production of DTE proteins compared to traditional methods.

Cost Burden of Raising A Child with Fetal Alcohol Spectrum Disorder

BACKGROUND: In Canada the incidence of Fetal Alcohol Spectrum Disorder (FASD) is estimated to be 1 in 100 live births. FASD is the leading cause of developmental and cognitive disabilities in Canada. No study has examined the cost to parents/caregivers of raising a child with FASD in Canada.

OBJECTIVES: To calculate an estimate of direct and indirect costs associated with raising a child with FASD at the patient level.

DESIGN/METHODS: Cross-sectional study design was used. Two-hundred and thirty (230) participants completed the study tool. Participants included caregivers of children from day of birth to 18 years of age, living in urban and rural communities throughout Canada. Participants completed the Health Services Utilization Inventory (HSUI). Key cost components were elicited: direct costs: medical, education, social services, out-of-pocket costs; and indirect costs: productivity losses. Total average costs per individual with FASD were calculated by summing the costs in each cost component, and dividing by the sample size. Costs were extrapolated to one year. A stepwise multiple regression analysis was used to identify significant determinants of costs and to calculate the adjusted annual costs of raising a child with FASD.

RESULTS: Total adjusted annual costs associated with FASD at the individual level was $31, 640 (95% CI $25,342; $38,642). Severity of the child’s condition, age, and relationship of the individual to the caregiver (biological, adoptive, kinship) were significant determinants of costs (p < 0.001). Thirty-two (32) percent of the total costs were paid by families caring for the children: The total annual cost to parent(s)/caregiver(s) of a child with FASD was $10,124.80. These costs were beyond the costs of raising a healthy child and only associated with costs of FASD.

CONCLUSION: Study results demonstrated thecost burden of FASD in Canada to parents/caregivers. Implications to practice, policy, and research are discussed.

Herbal and nutritional supplement use among college students in Qatar

There is increasing demand for herbal and nutritional supplements in the Middle East. This study aimed to examine the use of supplements by college students in Qatar and to elucidate users' views about them. A total of 419 college students completed a self-administered questionnaire. Almost half of the respondents (49.6%) had used supplements (ever users), with 32.7% reporting using them in the previous 6 months (current users). Of the latter, 27.7% had used herbal supplements, 56.2% vitamins and minerals and 56.9% non-vitamin, non-mineral, non-herbal supplements. Many participants considered supplements to be safer and more effective than conventional medicines. Supplements were preferred over conventional medicines for the treatment of digestive conditions and common respiratory ailments and for weight management. Educating health-care providers about the benefits and risks of supplements is imperative and will enable health-care practitioners to guide patients in making informed decisions about supplement use.

Use of complementary and alternative medicine among midlife Arab women living in Qatar

The prevalence of use of complementary and alternative medicine (CAM) is widespread and is growing worldwide. This cross-sectional study in Qatar examined the use of CAM and its correlates among Arab women in their midlife years. Women aged 40-60 years (n = 814) were recruited at primary care centres in Qatar and completed a specially designed, pre-tested questionnaire. Overall, 38.2% of midlife women in Qatar had used CAM in the previous 12 months. Nutritional remedies and herbal remedies were the most commonly used CAM therapies, followed by physical methods. Qatari nationality and higher level of education were independently associated with CAM use. Menopause transition status was not independently associated with use of CAM. The prevalence of CAM use by women in Qatar was high, consistent with other reports worldwide. It is essential to educate and inform patients and health-care providers about the benefits and limitations associated with CAM.

Interaction of constitutive photomorphogenesis 1 protein with protein-tyrosine phosphatase 1B suppresses protein-tyrosine phosphatase 1B activity and enhances insulin signaling

Recent studies reveal that COP1 suppresses the expression of gluconeogenetic genes and prohibits hepatic glucose production. To get more insight into COP1 in hepatic cells, we examined the impact of COP1 on insulin-responsive genes and insulin signaling. We found that COP1 increased the responsiveness of insulin-modulated genes to insulin in that it promoted the expression of insulin-induced genes and inhibited that of insulin-suppressed genes and that COP1 enhanced insulin signaling as it promoted phosphorylation of Akt and ERK as well as tyrosine phosphorylation of IRβ induced by insulin. To delineate the mechanism under which COP1 modulates insulin signaling, we examined the possibility that COP1 modulates the activity of PTP1B, the major insulin receptor tyrosine phosphatase. The results indicated that COP1 physically interacted with PTP1B and suppressed PTP1B phosphatase activity as well as the association of PTP1B with IRβ. We suggest that COP1 is a positive regulator of hepatic insulin signaling.

The effect of insulin intensification in children and young persons with Type 1 diabetes differs in relation to ethnic group; a prospective observational study

AIMS

We prospectively evaluated the effect of insulin intensification on glycaemic control and lipid levels in children and young persons with Type 1 diabetes in relation to ethnicity.

METHODS

In the first 2 years of a 3-year observation period, as part of routine clinical care, 231 children and young persons (40% white, 28% South Asian, 32% black) from a single clinic were offered intensive insulin therapy. After 2 years, 222 were on intensive therapy and their data were compared between ethnic groups at the end of year 3.

RESULTS

We observed ethnic differences in HbA(1c) levels during the study [study beginning and end: white children and young persons 77 and 70 mmol/mol (9.2 and 8.6%) vs. South Asian 72 and 68 mmol/mol (8.7 and 8.4%) vs. black 83 and 79 mmol/mol (9.7 and 9.4%), P-value for ANCOVA = 0.007]. By study end, South Asians had the lowest HDL cholesterol (2.0 vs. 1.4 vs. 1.6 mmol/l, P-value = 0.03) and highest triglyceride levels (0.9 vs. 1.8 vs. 1.0 mmol/l, P-value = 0.001). In linear mixed modelling, after adjustment for socio-economic deprivation and other covariates: (1) black ethnicity was associated with poorer glycaemic control (P < 0.001) and (2) South Asian ethnicity was associated with higher triglyceride levels (P < 0.001), independent of HbA(1c).

CONCLUSIONS

The effect of insulin intensification on glycaemic control and lipid profile in children and young persons with Type 1 diabetes differs in relation to ethnic group.

The association of ClipR-59 protein with AS160 modulates AS160 protein phosphorylation and adipocyte Glut4 protein membrane translocation

ClipR-59 is a membrane-associated protein and has been implicated in membrane signaling and vesicle trafficking. Recently, we have identified ClipR-59 as an Akt-interacting protein, and we have found that, by interacting with Akt, ClipR-59 modulates Akt subcellular compartmentalization and Akt substrate AS160 phosphorylation, thereby promoting Glut4 membrane translocation. Here, we have further investigated the regulatory effects of ClipR-59 on AS160 phosphorylation and subsequent adipocyte glucose transport. Our data showed that ClipR-59 interacted with AS160, which was mediated by the ankyrin repeats of ClipR-59 and regulated by insulin signaling. Moreover, the data also demonstrated that the interaction of ClipR-59 with AS160 was required for ClipR-59 to modulate Glut4 membrane translocation as ΔANK-ClipR-59, an AS160 interaction-defective mutant, failed to promote AS160 phosphorylation, Glut4 membrane translocation, and glucose transport induced by insulin in 3T3-L1 adipocytes. Because ClipR-59 also interacts with Akt and enhances the interaction between Akt and AS160, we suggest that ClipR-59 functions as a scaffold protein to facilitate Akt-mediated AS160 phosphorylation, thereby regulating glucose transport.

Anaesthesia and epilepsy

Epilepsy is the most common serious neurological disorder, with a prevalence of 0.5-1% of the population. While the traditional antiepileptic drugs (AEDs) still play a significant role in treatment of seizures, there has been an influx of newer agents over the last 20 yr, which are now in common usage. Anaesthetists are frequently faced with patients with epilepsy undergoing emergency or elective surgery and patients suffering seizures and status epilepticus in the intensive care unit (ICU). This review examines perioperative epilepsy management, the mode of action of AEDs and their interaction with anaesthetic agents, potential adverse effects of anaesthetic agents, and the acute management of seizures and refractory status epilepticus on the ICU. Relevant literature was identified by a Pubmed search of epilepsy and status epilepticus in conjunction with individual anaesthetic agents.

Bullying of junior doctors prevails in Irish health system: a bitter reality

Workplace bullying in health systems is a well known fact. It leads to not only breakdown in teamwork but also has significant affect on the individual's personal life. True prevalence of bullying in junior doctors working in Ireland is unknown. Our aim of study was to find out the prevalence of bullying in junior doctors working hospitals in south and western counties of Ireland and to assess its effects on the productivity of work and family life and to identify the common source of bullying. We carried out a questionnaire survey. A total of 950 questionnaires were sent. Response rate was 51%. Our sample is 15% of the target population of all the hospital junior doctors. 30% of the responders claimed to be subjected to one or more bullying behaviors. Doctors from European Union (EU) reported significantly less rate of bullying compares to non EU doctors. Our results are in line with the results of studies conducted in United Kingdom. This study shows the magnitude and source of the problem. We conclude that bullying is a common problem in Irish health system. Increased awareness and zero tolerance are required to eradicate bullying.

Timing of laparoscopic cholecystectomy in acute cholecystitis

BACKGROUND

Laparoscopic cholecystectomy is associated with an increased conversion rate in acute cholecystitis.

AIM

To review the operative management of symptomatic cholelithiasis with particular reference to conversion rates and morbidity for laparoscopic cholecystectomy for acute cholecystitis.

METHODS

Patients undergoing cholecystectomy between January 1994 and December 1998 were recruited. Demographic details, diagnosis, duration of symptoms, treatment, outcome, post-operative stay and complications were recorded.

RESULTS

Complete data were available on 482 patients (84%). Laparoscopic cholecystectomy was attempted in 120 of 132 patients (91%) with acute cholecystitis and 329 of 350 patients (94%) with non-acute gallbladder disease. Conversion rates were 27% (33/120) and 6.7% (22/329) for acute and non-acute gallbladder disease, respectively (p < 0.001 chi2 test). Relating the interval from onset of symptoms to surgery, conversion rates for acute cholecystitis were: < 3 days, 5/17 (29%); 4 to 42 days, 14/59 (23%) and > 42 days, 14/44 (31%). There were three bile duct injuries, two in the delayed (> 45 days) acute group and one in the non-acute group.

CONCLUSION

Early laparoscopic cholecystectomy is the treatment of choice for acute cholecystitis, but is associated with a high conversion rate independent of the timing of surgery.

Factors affecting the spread of bupivacaine in the adult thoracic paravertebral space

Factors affecting the spread of bupivacaine in the paravertebral space were investigated in patients undergoing paravertebral nerve blocks for the treatment of chronically painful conditions. Injections of bupivacaine 0.5%, 10-15 ml mixed with depomedrone up to 80 mg were repeated at 2-wk intervals up to a maximum of four times. A blinded observer mapped out the subsequent distribution of sensory loss to cold on both sides of the torso at 5-min intervals after each injection. Age, sex, height and weight did not correlate with the block; nor did injectate volume, mass of bupivacaine, previous posterolateral thoractomy and spread of radiocontrast. Injections repeated at 2-wk intervals in the same patient resulted in different degrees of spread that were unrelated to one another. Time to peak onset of blockade was 40 min in 95% of patients. A single bolus of bupivacaine produces a safe but unpredictable block. Yet to be defined physical properties and anatomical factors are probably key determinants of the spread of bupivacaine in the paravertebral space. This single bolus technique may be better supplanted by a reversion to the older multiple level injection technique.

Spinal endoscopy in chronic low back pain with radiculopathy. A prospective case series

All 38 patients listed for day-case spinal endoscopy over a 12-month period (April 1998 - April 1999), who had chronic severe low back pain with a radiculopathic element, were studied prospectively. The mean [range] pain duration before treatment was 10.9 [2-26] years and 50% had failed back surgery syndrome. In all patients in whom treatment was completed (n = 34), the pain-generating nerve roots were located through symptom interaction with the patient. All had epidural scar tissue, 14 (41%) having dense adhesions. Mobilisation of adhesions around the nerve root (neuroplasty) was performed so that a pocket was formed for the subsequent placement of bupivacaine, Depomedrone and clonidine. No intra-operative complications occurred and side-effects were minimal. Follow-up over a 12-month period showed statistically significant reductions in pain scores and disability. Spinal endoscopy may be the diagnostic method of choice for epidural fibrosis. It has substantial therapeutic and research potential. Prospective randomised studies are required.

Day case laparoscopic cholecystectomy is feasible

BACKGROUND

Laparoscopic cholecystectomy is the operation of choice for cholelithiasis.

AIMS

The aims of our study were to assess the feasibility of day case laparoscopic cholecystectomy (DCLC) in selected patients.

METHODS

DCLC was introduced in this unit in July 1999. The first 50 patients were prospectively evaluated up to February 2001.

RESULTS

All patients were under 55 years of age with an ASA grade of I (n = 48) or II (n = 2). The mean age was 41.1 years (range 20-55 years) and the male:female ratio was 1:6. All patients had a standard anaesthetic protocol. Patients were discharged 10 to 12 hours postoperatively with a pro forma, which was reviewed at one week in the clinic. The conversion rate was 2%. Three required overnight admission due to excessive nausea, hypertension and for an unforeseen psychosocial problem. Ninety per cent of patients were suitable for same day discharge. No patient required subsequent readmission.

CONCLUSION

DCLC is feasible and safe in carefully selected patients and has the advantages of convenience and cost-effectiveness.

Cloning and characterization of a 72-kDa inositol-polyphosphate 5-phosphatase localized to the Golgi network

The inositol-polyphosphate 5-phosphatase enzyme family removes the 5-position phosphate from both inositol phosphate and phosphoinositide signaling molecules. We have cloned and characterized a novel 5-phosphatase, which demonstrates a restricted substrate specificity and tissue expression. The 3.9-kb cDNA predicts for a 72-kDa protein with an N-terminal proline rich domain, a central 5-phosphatase domain, and a C-terminal CAAX motif. The 3. 9-kilobase mRNA showed a restricted expression but was abundant in testis and brain. Antibodies against the sequence detected a 72-kDa protein in the testis in the detergent-insoluble fraction. Indirect immunofluorescence of the Tera-1 cell line using anti-peptide antibodies to the 72-kDa 5-phosphatase demonstrated that the enzyme is predominantly located to the Golgi. Expression of green fluorescent protein-tagged 72-kDa 5-phosphatase in COS-7 cells revealed that the enzyme localized predominantly to the Golgi, mediated by the N-terminal proline-rich domain, but not the C-terminal CAAX motif. In vitro, the protein inserted into microsomal membranes on the cytoplasmic face of the membrane. Immunoprecipitated recombinant 72-kDa 5-phosphatase hydrolyzed phosphatidylinositol 3,4,5-trisphosphate and phosphatidylinositol 3, 5-bisphosphate, forming phosphatidylinositol 3,4-bisphosphate and phosphatidylinositol 3-phosphate, respectively. We propose that the novel 5-phosphatase hydrolyzes phosphatidylinositol 3,4, 5-trisphosphate and phosphatidylinositol 3,5-bisphosphate on the cytoplasmic Golgi membrane and thereby may regulate Golgi-vesicular trafficking.

Induction of postnatal schwann cell death by the low-affinity neurotrophin receptor in vitro and after axotomy

Schwann cells express the low-affinity neurotrophin receptor (p75), but no role for either the neurotrophins or their cognate receptors in Schwann cell development has been established. We have found that Schwann cells isolated from postnatal day 1 (P1) or P2 mice that were p75-deficient exhibited potentiated survival compared to wild-type cells after growth factor and serum withdrawal. There was, however, no disparity in the survival of p75-deficient and wild-type Schwann cells isolated at embryonic day 15, suggesting that the death-inducing effects of p75 are developmentally regulated. A comparable degree of cell death was also observed in the sciatic nerves of both wild-type and p75-deficient mice at P1. However, 24 hr after axotomy, there was a 13-fold increase in the percentage of apoptotic nuclei in the distal nerve stumps of the transected sciatic nerves of neonatal wild-type but not p75-deficient mice. The expression of both the p75 and nerve growth factor (NGF) genes was upregulated after axotomy in neonatal wild-type nerves. Collectively, these results suggest that NGF-mediated activation of p75 is likely to be an important mediator of Schwann cell apoptosis in the context of peripheral nerve injury.

Opposite patterns of P300 asymmetry in schizophrenia are syndrome related

In schizophrenia reduction of the P300 amplitude is a robust statistical finding but with inconsistent evidence of symptom correlates and of lateral asymmetry. Here relations were examined with active and withdrawn syndromes which in other cognitive and electrophysiological measurement modalities have been associated with opposite functional asymmetries. A standard oddball detection task was used to elicit auditory evoked potentials from dextral DSM-IV schizophrenic patients. On clinical ratings blind to the psychophysiology, eight were classified as withdrawn and 12 had a predominance of active syndrome features. Both patient groups had congruent P300 maxima at Pz or P4, attesting to their application to the detection task. Syndromes were differentiated by opposite asymmetries in P300, N200-P300 and N100 amplitudes at the posterior temporal sites: a reduction in P300 and N200-P300 amplitudes on the left in the active patients, and a reduction on the right in the withdrawn patients, with the opposite asymmetries in N100 amplitudes. The syndrome-related asymmetries in P300, also manifested in earlier attentional (N100) components are interpreted in terms of thalamo-cortical arousal systems having generalised, internalised influences, rather than in terms of later cognitive processes underpinning the P300. The findings endorse a syndromal approach to laterality research in schizophrenia.

A prospective, randomized comparison of preoperative and continuous balanced epidural or paravertebral bupivacaine on post-thoracotomy pain, pulmonary function and stress responses

Both epidural and paravertebral blocks are effective in controlling post-thoracotomy pain, but comparison of preoperative and balanced techniques, measuring pulmonary function and stress responses, has not been undertaken previously. We studied 100 adult patients, premedicated with morphine and diclofenac, allocated randomly to receive thoracic epidural bupivacaine or thoracic paravertebral bupivacaine as preoperative bolus doses followed by continuous infusions. All patients also received diclofenac and patient-controlled morphine. Significantly lower visual analogue pain scores at rest and on coughing were found in the paravertebral group and patient-controlled morphine requirements were less. Pulmonary function was significantly better preserved in the paravertebral group who had higher oxygen saturations and less postoperative respiratory morbidity. There was a significant increase in plasma concentrations of cortisol from baseline in both the epidural and paravertebral groups and in plasma glucose concentrations in the epidural group, but no significant change from baseline in plasma glucose in the paravertebral group. Areas under the plasma concentration vs time curves for cortisol and glucose were significantly lower in the paravertebral groups. Side effects, especially nausea, vomiting and hypotension, were troublesome only in the epidural group. We conclude that with these regimens, paravertebral block was superior to epidural bupivacaine.

Deletion of chromosome 18 with cardiomyopathy

A female child is described with deletion of chromosome 18 and cardiomyopathy. The clinical features and treatment of the case are described, and the literature of chromosome 18 reviewed.

Retinoid-mediated signaling pathways in CD38 antigen expression in myeloid leukemia cells

The lymphocyte cell surface antigen CD38, which was originally described as a differentiation marker, has emerged as an important multifunctional protein. Its most intriguing and well characterized function is its ability to catalyze the synthesis of cyclic ADP-ribose (cADPR) from NAD. cADPR serves as an important second messenger in controlling the release of intracellular calcium from ryanodine-sensitive intracellular pools. By virtue of its ability to synthesize cADPR as well as to act as an adhesion and signal transduction molecule, CD38 may play a role in such diverse physiological processes as cell growth, apoptosis, differentiation, and inflammation. Equally interesting is the pattern of CD38 expression in hematopoietic cells. In the bone marrow, early precursor cells predominantly express CD38 antigen, whereas mature circulating blood cells lack or express very low levels. The expression is also high on malignant hematopoietic cells and thus may be of prognostic relevance in certain leukemias. Presently, there is little information available on the factors that regulate the expression of CD38 antigen in hematopoietic cells. In this review, we summarize recent findings on the regulation of CD38 antigen by retinoids (vitamin A and related compounds). At least in the myeloid cell lineage, retinoids appear to be exquisitely potent and specific inducers of CD38 antigen expression, and retinoid-induced expression of CD38 is mediated via activation of the retinoic acid-alpha (RAR alpha) nuclear receptor.

Pleural bupivacaine placement for optimal postthoracotomy pulmonary function: a prospective, randomized study

OBJECTIVE

To determine dependent chest tube losses of bupivacaine with paravertebral versus interpleural administration, thereby helping to explain the significant differences in pulmonary function that exist between these two techniques.

DESIGN

A prospective, randomized study.

SETTING

A single hospital.

PARTICIPANTS

Twelve adult patients undergoing posterolateral thoracotomies.

INTERVENTIONS

Paravertebral or interpleural administration of bupivacaine.

MEASUREMENTS AND MAIN RESULTS

Analgesia, as assessed by visual analog pain scores and patient-controlled morphine requirements, was similar in both groups. Postoperative spirometric values were significantly better at most times with the paravertebral route of administration. Dependent chest tube bupivacaine losses were approximately four times higher in the interpleural group.

CONCLUSION

Local anesthetic on the diaphragm might actively impair respiratory function through diaphragmatic and abdominal muscle weakness, while failing to contribute to pain relief.

Cytokines which signal through the LIF receptor and their actions in the nervous system

A number of different cytokines, each initially characterized on the basis of very different biological activities, all have very similar signalling pathways and share a similar tertiary structure. These cytokines include leukaemia inhibitory factor, ciliary neuronotrophic factor, oncostatin M, growth-promoting activity and cardiotrophin 1. They all have been found to regulate a number of properties of cells of the developing and mature nervous system in vitro and thus are neuroregulatory cytokines. The actions of these cytokines include regulation of neurotransmitter phenotype, differentiation of neuronal precursor cells both in the peripheral nervous system and in the spinal cord, survival of differentiated neurons, and regulation of development of both astrocytes and oligodendrocytes. In addition, studies in animal models show that these factors can rescue sensory and motor neurons from axotomy-induced cell death, which suggests that they can act as trauma factors for injured neurons. Analysis of the expression patterns of the different neuroregulatory cytokines and their receptors reveals that the receptors are expressed throughout nervous system development and following trauma, whereas the cytokines show temporal and spatial specific expression patterns. This is consistent with the idea that specific cytokines have specific roles in neural development and repair, but that their signalling pathways are shared. The phenotypes of the receptor knockouts show clear deficits in nervous system development, indicating a crucial role for LIF receptor signalling. Knockouts of individual cytokines are less dramatic, but LIF and CNTF knockouts do reveal deficits in maintenance of motor neurons or following trauma. Thus, whereas LIF and CNTF have clear roles in maintenance and following trauma, it is unclear which of the cytokines is involved in nervous system development. In clinical terms, these findings add further support to the use of these cytokines in nervous system trauma and disease.

Effect of polyunsaturated fatty acids in obese mice

Genetically obese (ob/ob) mice display a variety of metabolic differences from lean litter mates. In the obese state, fatty acid desaturation-elongation in brown adipose tissue mitochondria is apparently altered, resulting in differences in membrane fatty acid composition. This change in membrane lipid environment appears to influence GDP binding and therefore the activity of the proton conductance pathway associated with regulation of energy expenditure in these animals. In liver, binding of insulin to the nuclear membrane is increased by feeding a high polyunsaturated/saturated (P/S) diet fat. Consumption of a high P/S diet decreased mRNA levels for fatty acid synthase, acetyl-CoA carboxylase, malic enzyme, and pyruvate kinase in obese and lean animals. Expression of mRNA for these lipogenic enzymes was higher in obese animals and suggests that obese mice may be resistant to polyunsaturated fatty acid feedback control of gene expression.

Role of leukaemia inhibitory factor (LIF) in rat peripheral nerve regeneration

The cytokine leukaemia inhibitory factor (LIF) favours the survival and growth of axons in vitro. The efficacy of this factor in the in vivo model has been the aim of this study. Following nerve transection and immediate entubulation repair in the rat sciatic nerve, this study demonstrated that (1) LIF promotes the growth of a population of axons of greater cross-sectional area after 6 and 12 weeks in comparison to either saline (negative control) or basic fibroblast growth factor (bFGF) (positive control), (2) LIF improves the nerve conduction velocity of regenerating axons, (3) LIF has a positive effect on skeletal muscle mass following nerve repair, (4) the benefits of LIF on skeletal muscle appear to be somewhat independent of reinnervation as similar observations are made where there is no growth of a tissue bridge within the tube, and (5) the effects of LIF seem to be potentiated by the addition of fibronectin.

Dietary lipids influence insulin action

Insulin binding and insulin responsiveness are altered by dietary fat-induced changes in the fatty acid composition of the adipocyte plasma membrane. Feeding a high P/S diet increased polyunsaturated fatty acid content of major membrane phospholipids of adipocyte plasma membrane in normal and diabetic animals, increased membrane linoleic acid content, and prevented a decrease in arachidonic acid level in diabetic animals. The high P/S diet increased insulin binding in control animals. Animals fed the high P/S diet had significantly higher rates of insulin-stimulated glucose transport and lipogenesis than did animals fed the low P/S diet. Feeding a high P/S diet significantly increased the amount of glucose transported when expressed as a function of the specific amount of insulin bound. To determine if dietary fat-induced alterations in the fatty acid composition of skeletal muscle lipid alter insulin-dependent and basal muscle metabolism, contralateral epitrochlearis and extensor digitorum longus muscles were isolated and incubated in vitro. High levels of dietary omega-3 fatty acids reduced PGE2 and PGF2 alpha synthesis in extensor digitorum longus and epitrochlearis muscle. Insulin increased glucose and amino acid transport; the increase in glucose transport by insulin was significantly greater after consumption of the high omega-3 fatty acid diet. Rats fed high levels of omega-3 fatty acids showed reduced net protein degradation in the presence and absence of insulin due to decreased rates of protein degradation and synthesis. These experiments indicate that high levels of dietary omega-3 fatty acids alter muscle membrane composition, glucose transport, and metabolism of muscle protein. To determine if dietary fatty acids alter the onset of diabetes and insulin binding to liver nuclei in spontaneously diabetic rats, weanling rats were fed chow or semipurified diets containing 20% (w/w) fat of either high or low P/S ratio. Feeding a high P/S diet increased insulin binding to liver nuclei of control and diabetic animals. Although diet did not alter the onset of diabetes, insulin binding to liver nuclei is higher in animals at the onset of diabetes than in highly diabetic animals. Eight-week-old female C57 B 6J lean and ob/ob mice were fed semipurified diets containing 20% (w/w) fat of either high or low P/S ratio to investigate the effect of diet on specific binding of insulin to liver nuclei. Insulin binding was highest in nuclei from lean mice fed a high P/S diet. Specific binding of insulin to nuclei from obese mice was also increased by the high P/S diet, but to a lesser extent.(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary fat: exogenous determination of membrane structure and cell function

Evidence indicates that principal features of the membrane involve structural organization of lipids in the form of a bilayer with functional proteins either bound to the bilayer surface or inserted into the bilayer and interacting within specific domains in the lipid milieux. In homeotherms, intrinsic and extrinsic factors apparently form the basis for determination of membrane lipid composition and thus membrane physicochemical properties. Moreover, many intrinsic metabolic controls, such as fatty acid desaturation and phospholipid biosynthesis, may be attenuated by change in the nature of the extrinsic or dietary influence. This review will focus on the role of dietary fat as a determinant of subcellular structural constituents to illustrate that feeding nutritionally adequate diets differing in fatty acid composition can induce physiological transitions in membrane function involving the activity of enzymes responsible for synthesis of membrane constituents, hormone-activated functions and expression of activity in the cell nucleus.

Sensorimotor cortical projections to the primate cuneate nucleus

The organization of the corticocuneate pathway was investigated in monkeys by using the anterograde and retrograde axonal transport of either horseradish peroxidase (HRP) or wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP). Injection of either tracer into the precentral cortex (centered on area 4) results in heavy anterograde labeling in the tegmental region, which lies immediately ventrolateral to the cuneate nucleus, particularly at levels caudal to the obex. On the other hand, injections of the same tracers involving areas 3b, 1, and 2 cause anterograde labeling mainly within the core (pars rotunda of Ferraro and Barrera, '35, Arch. Neurol. Psychol. 33:262-75) of the cuneate nucleus. Anterograde labeling is also evident in the rostral parts of the cuneate nucleus, especially after injections involving areas 1 and 2. Injections restricted largely to area 3b cause anterograde labeling preferentially in the core of the cuneate nucleus. After injection of HRP or WGA-HRP into the dorsal medulla, retrogradely labeled neurons are present both in the pre- and postcentral gyrus, but their location depends upon the sites and extent of the injection site. When the tracer diffuses into the underlying tegmental area, many retrogradely labeled neurons appear in the precentral motor cortex, principally in area 4 although some of them also occur in area 6. With smaller injections, largely restricted within the cuneate nucleus, most labeled neurons are present in the postcentral gyrus, with the largest population in areas 1 and 2; a smaller number of small neurons in area 3b are best demonstrated with WGA-HRP; and area 3a contains the smallest complement of retrogradely labeled neurons. The data from these studies suggest a segregation of pre- and postcentral afferents in the ventral tegmental region and the cuneate nucleus, respectively. These findings pertaining to the corticocuneate projection in the monkey are discussed in relation to the parallelism between monkeys and cats possible physiological implications of the anatomical organization described, and conflicting evidence in the neurophysiological observations obtained, by earlier investigators, by antidromic and orthodromic activation of this pathway.

Arborizations of single corticofugal axons in the feline cuneate nucleus stained by iontophoretic injection of horseradish peroxidase

Terminal aborizations and synaptic boutons of cortical afferents to the cuneate nucleus were examined by light and electromicroscopy following intra-axonal staining with HRP. Two populations of afferents are described: (1) direct corticocuneate fibers, and (2) fibers destined for the spinal cord which issue collateral branches to the cuneate nucleus. Corticocuneate terminals primarily contact fine dendrites located in the ventral parts of the nucleus. These results are discussed in relation to previous anatomical findings and to new concepts of cuneate nucleus organization.

Glutamic acid decarboxylase-containing neurons in the dorsal column nuclei of the cat

The retrograde transport of horseradish peroxidase (HRP) and immunocytochemistry for glutamic acid decarboxylase (GAD) have been employed to examine whether local circuit neurons (LCNs) exist in the dorsal column nuclei (DCN) and whether these neurons may be GABA-ergic. Observations focused on the dorsal part of the middle cuneate nucleus (MCd), since this region has been previously shown to contain projecting neurons whose axons terminate almost exclusively in the contralateral thalamus. After large injections of HRP in the nucleus ventralis posterolateralis and surrounding structures of the feline thalamus, the majority of neurons in MCd are labeled. These represent about 89% of the neurons in MCd as counted in 40-microns frozen sections, and about 69% as counted in plastic-embedded, 2.5-microns-thick section. Unlabeled by the same injections are some medium to large neurons at the dorsal rim of MCd, and many characteristically small (mean = +/- 250 microns2) neurons at the periphery of the cell clusters formed by thalamic-projecting neurons. These small neurons represent 10-12% of the neuronal population of MCd, as counted in 40-microns-thick frozen sections, and about 30%, as counted in plastic-embedded, 2.5-microns-thick sections. Neurons in this size range are also unlabeled after injection of retrograde tracer in the pretectal area, inferior and superior colliculi, inferior olivary complex, and/or spinal cord. These injections, however, result in the labeling of neurons along the dorsal rim of MCd and/or in other regions of the cuneate nucleus. In adult, colchicine-treated cats, the use of anti-GAD serum reveals a population of labeled neurons uniformly distributed throughout the DCN. In MCd, these are small (mean = +/- 235 microns2) neurons mainly intercalated between cell clusters, and represent about 25% of the neuronal population of this nuclear subdivision as counted in plastic-embedded, 2.5-microns-thick sections. Labeled processes densely infiltrate the cell clusters, and labeled varicosities appear to cover the soma and dendrites of unlabeled neurons. At the electron-microscopic level, most labeled profiles contain vesicles and correspond to F boutons usually involved in "axoaxonic" contacts with terminals of dorsal root afferent and presynaptic to dendrites. Other vesicle-containing, GAD-positive endings seem to correspond to the P boutons described by Ellis and Rustioni (1981) and are believed to be, at least in part, of dendritic origin. It is suggested that GAD-positive neurons are GABA-ergic LCNs and that these can mediate both pre- and postsynaptic inhibition.(ABSTRACT TRUNCATED AT 400 WORDS)

Improved visualization of neurons labeled with horseradish peroxidase: silver-intensification of the pyrocatechol/p-phenylenediamine reaction product

A silver intensification procedure suitable for use with pyrocatechol/p-phenylenediamine (PC-PPD) product of the horseradish peroxidase (HRP) reaction is described. Qualitative and quantitative results from retrogradely labeled neurons in the cat cortex after thalamic injection of HRP demonstrate an increase of the intensity of labeling and in the number of darkly labeled cells after the intensification procedure. In both the non-intensified and the intensified PC-PPD reacted tissue the sensitivity was comparable to that of TMB-treated material. The ratio of lightly to darkly labeled neurons was very similar in intensified PC-PPD and TMB material, suggesting that the lightly labeled cells may have fewer terminals present at the level of the injected target.

The corticocuneate pathway in the cat: relations among terminal distribution patterns, cytoarchitecture, and single neuron functional properties

A combined anatomical and physiological strategy was used to investigate the organization of the corticocuneate pathway in the cat. The distribution of the corticocuneate projection was mapped by means of the anterograde horseradish peroxidase (HRP) labeling technique and correlated with the nuclear cytoarchitecture in Nissl and Golgi material, the distribution of retrogradely labeled relay cells after HRP injections in the ventrobasal complex of the thalamus, and the topographic organization derived from single- and multiunit recordings in the decerebrate, unanesthetized cat. This approach provided details about the arrangement of the corticocuneate pathway that were not available from previous studies with anterograde degeneration methods. On the basis of cytoarchitectonic and connectional features, a number of subdivisions are identified in the cuneate nucleus, each of which is associated with characteristic functional properties. In agreement with previous studies, it is found that a large portion of the cuneate nucleus, the middle dorsal part (MCd), is exclusively devoted to the representation of cutaneous receptive fields on the digits. This "core" region contains more thalamic projecting neurons than any other subdivision of the cuneate nucleus. A topographic arrangement also exists in the subdivisions of the rostral cuneate and of the nuclear region ventral to MCd, although in these, receptive fields are larger and predominantly, but not exclusively, related to deep receptors and involve the arm, shoulder, and trunk. Observations on corticocuneate projections were based on injections, mainly focused on functional subdivisions of the primary somatosensory cortex (SI) as described by McKenna et al. (1981). Although cortical projections are mainly to cuneate regions other than its core, a significant proportion of fibers from the region of SI where the digits are represented (particularly area 3b) do project to the MCd region of the cuneate nucleus. Similarly, nuclear areas associated with receptive fields on the arm and trunk are labeled after injection in SI arm and trunk regions, respectively. Thus, a close topographic relationship appears to exist between the somatosensory cortex and cuneate regions related to the same body representation, although nuclear regions in which receptive fields on the neck area are represented receive very sparse or no detectable cortical projections even when the injection of the tracer involves the entire sensorimotor cortex.(ABSTRACT TRUNCATED AT 400 WORDS)

Properties of purifed quinonoid dihydropterin reductase

Quinonoid dihydropterin reductase has been purified to homogeneity from sheep liver, sheep brain, and beef adrenal medulla. Each of these enzymes has a molecular weight of about 45 000–55 000, and is composed of two subunits of half that weight. The subunits of the sheep liver reductase have identical charge, size, and N-terminal amino acid residue. The reductase exists in solution over a wide range of concentrations as the dimer. A dimer covalently linked by dimethylsuberimidate retains full activity. A number of kinetic properties of quinonoid dihydropterin reductase, including inhibition by thiol reagents and by pterin analogues, are reported.