A study on multivariable process control using message passing across embedded controllers

Multivariable process control forms an important part of modern day control. While hardwired controllers still constitute the basic component of such control systems, with reducing communication latencies, controllers on the network are being mooted as a viable alternative. These controllers promise a large number of advantages in terms of reduction in wiring and greater flexibility in implementing supervisory control systems. In this paper, a study is presented which shows that UDP (User Datagram Protocol) can actually be used for real-time multivariable process control. Latency reduction algorithms used in high performance message passing systems have been used.

Spectrum of radiological changes in hypertensive children with reversible posterior leucoencephalopathy

We prospectively studied 19 children with severe hypertension to evaluate the spectrum of radiological changes, severity and reversibility of this entity. All of them were subjected to clinical and biochemical evaluation, followed by magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA). Headache was seen in 17 children, 13 had confusion and drowsiness, 12 had nausea and vomiting, 10 patients had visual disturbances, seizure and dyspnoea. Only two had focal neurological deficit (one with right facial palsy and another with right lateral rectus palsy). Of these 19 children, 15 patients had hypertensive retinopathy and four had normal fundi. The positive MRI findings in 17/19 patients were: bilateral leukoencephalopathic changes in occipitoparietal region (9/17), diffuse white/grey matter lesion (3/17) patients, brain stem hyperintensity (2/17) and haemorrhagic lesions (3/17). On MRA, 12/19 patients had attenuation of cerebral arteries of different degree. On follow up, MRI findings resolved in all except three patients. All patients had normal MRA on follow up, except one with persistent minimal attenuation of middle cerebral artery and another had spasm in anterior, middle and posterior cerebral arteries. The intracranial abnormalities in these patients with severe hypertension were reversible in many of the cases after control of blood pressure was achieved. We therefore conclude that severe hypertension may lead to leuoencephalopathy, which had a wide radiological spectrum. A better understanding of this complex syndrome may obviate unnecessary investigations and allow management of associated problems in prompt and appropriate ways.

Mechanisms of edge-localized-mode mitigation by external-magnetic-field perturbations

Particle and energy transport in the tokamak edge transport barrier is analyzed in the presence of magnetic field perturbations from external resonant coils. In recent experiments such coils have been verified as an effective tool for mitigation of the edge-localized modes of type I. The observed reduction of the density in plasmas of low collisionality is explained by the generation of charged particle flows along perturbed field lines. The increase of the electron and ion temperatures in the barrier is interpreted by the reduction of perpendicular neoclassical transport with decreasing density and nonlocality of parallel heat transport. The found modification of the pressure gradient implies the stabilization of ballooning-peeling MHD modes responsible for type I ELMs.

Lack of impact of artesunate on the disposition kinetics of sulfadoxine/pyrimethamine when the two drugs are concomitantly administered

OBJECTIVE

To determine the effect of artesunate (AT) on the disposition kinetics of sulfadoxine/pyrimethamine (SP) in humans.

METHODS

In a randomized cross-over study, 16 healthy volunteers were given a dose of three SP tablets containing 500 mg of sulfadoxine (SDX) and 25 mg of pyrimethamine (PYR) (=SP group), while the second arm received three SP tablets + two AT tablets of 200 mg in total followed by 100 mg AT for the next 4 days (SP+AT group). Blood samples (100 microl) were collected by means of a finger prick and dried on filter paper. The blood spots were wrapped in polythene folders and stored at room temperature until analysis. The samples were assayed using high-performance liquid chromatographic methods.

RESULTS

The peak concentration C(max)), time required to attain peak concentration (T(max)), half-life (t ((1/2))) and area under the plasma concentration-time curve (AUC) were determined. The C(max) of SDX were 92.9 and 98.9 microg/ml for the SP and SP+AT arms, respectively; for PYR, these were 0.86 and 0.79 microg/ml, respectively. The T(max) of SDX were 10 and 8 h for the SP and SP+AT arms, respectively; for PYR, these were 4.0 and 3.0 h, respectively. The AUC(0-288) of SDX were 15,840 and 18,876 microg/ml h for the SP and SP+AT arms, respectively; for PYR, they were 124 and 112 microg/ml h, respectively. The t ((1/2)) of values for SDX were 165 and 180 h for the SP and SP+AT arms, respectively; for PYR, these were 158 and 177 h, respectively. There was no statistically significant difference between the C(max), T(max), AUC(0-288) and t ((1/2)) between the two arms (p > 0.05).

CONCLUSION

Taking AT concomitantly with SP does not have any impact in the disposition of SP.

Visual loss in the setting of allergic fungal sinusitis: pathophysiology and outcome

Objective:

To hypothesise the probable pathophysiological mechanism responsible for visual loss in allergic fungal sinusitis, other than direct compression.

Design:

Retrospective, non-randomised case series. Out of 274 cases of allergic fungal sinusitis, four cases with sudden visual loss were enrolled into the study. The fourth case had visual loss on the contralateral side to bony erosion of the lateral wall of the sphenoid sinus.

Interventions:

All four cases were evaluated with fungal smear, immunoglobulin (Ig) E titres, visual evoked potentials, non-contrast computed tomography and magnetic resonance imaging of the paranasal sinuses, and fundus examination. They then underwent endoscopic sinus debridement followed by intravenous methylprednisolone.

Outcome measures:

Improvement in vision.

Results:

All four cases experienced an improvement in vision: full recovery in three cases and partial improvement in one case.

Conclusion:

In view of the operative, radiological and laboratory findings for case four, with the suggestion of a hyperimmune response to fungal antigens (in the form of raised IgE titre and positive fungal serology), we suggest that a local immunological reaction to fungal antigens might be responsible for the observed visual loss in cases of allergic fungal sinusitis, in addition to mechanical compression of the optic nerve.

Hematological and molecular response evaluation of CML patients on imatinib

BACKGROUND

The BCR-ABL tyrosine kinase is a well-validated therapeutic target in Chronic Myeloid Leukemia (CML). Imatinib mesylate (formerly STI-571), a tyrosine kinase inhibitor is highly effective at the hematological, cytogenetic and molecular level in CML.

AIMS

To evaluate hematological and molecular response in CML patients on Imatinib and also the side effects of the therapy if any.

METHODS AND MATERIALS

Sixteen patients were diagnosed as having chronic phase CML at Kasturba Medical College Hospital, Attavar, Mangalore during the period of two years from January 2004 to January 2006 and were given Imatinib at 400 mg/day orally. They were followed closely over a period of 1 year using the following parameters: (1) monthly clinical examination, (2) monthly peripheral blood smear examination, (3) real time reverse transcriptase quantitative polymerase chain reaction (RT Q-PCR) for BCR-ABL at the end of every 6 months. The findings were evaluated after one year for hematological and molecular response achieved.

RESULTS

Fifteen (93.75%) patients achieved complete hematological response within three months of therapy. Six (37.5%) patients achieved complete molecular response(CMR) within six months of therapy as measured by real time RT Q-PCR. None of the patients who did not achieve CMR within first six months of therapy achieved it after one year of therapy. No patient lost the initial response. The median BCR--ABL/ABL value at the end of the six months was 11% and at the end of the one year was 3.38%.

CONCLUSION

Imatinib mesylate is highly effective in the treatment of chronic phase CML and so should be considered as the drug of first choice in CML. Molecular response evaluation after six months can predict the subsequent molecular response and can also be usedas a surrogate monitor of the marrow cytogenetic response to imatinib therapy in CML.

Hibernoma: MRI features in eight consecutive cases

AIM

To describe the preoperative magnetic resonance imaging findings of eight histologically-proven cases of hibernoma.

MATERIALS AND METHODS

The site, size, and signal characteristics of eight consecutive hibernomas were retrospectively assessed on T1-weighted spin-echo and short T1 inversion recovery (STIR)/fat-saturated T2-weighted fast spin echo magnetic resonance images. Four patients also had gadolinium-enhanced fat-saturated T1-weighted spin echo imaging. Patient age and sex, and duration of symptoms were recorded.

RESULTS

Three female and five male patients with an average age 36 years (range 16-53 years) were included. Seven lesions occurred in the thigh, four in the anterior compartment and three in the posterior compartment. One lesion occurred superficial to the scapula. All cases demonstrated common magnetic resonance imaging findings of a well-defined, heterogeneous mass, slightly or clearly hypo-intense to subcutaneous fat on T1-weighted spin-echo images, with prominent thin low signal bands throughout the tumour. The lesions failed to fully suppress on STIR or fat-saturated T2-weighted images. Only one of the four contrast-enhanced studies demonstrated increased vascularity in the tumour.

CONCLUSION

The MRI findings of a lesion that is diffusely slightly hypointense to surrounding subcutaneous fat, should prompt the operator to consider hibernoma in the differential diagnosis.

Mini-trabeculectomy in comparison to conventional trabeculectomy in primary open angle glaucoma

PURPOSE

To evaluate the safety and efficacy of mini-trabeculectomy in comparison to conventional trabeculectomy in primary open angle glaucoma (POAG).

METHODS

A prospective interventional study of mini-trabeculectomy versus conventional trabeculectomy was undertaken on 60 eyes of 54 medically uncontrolled POAG patients requiring glaucoma surgery. They were divided into two groups: Group I underwent mini-trabeculectomy (30 eyes of 26 patients) and Group II underwent conventional trabeculectomy (30 eyes of 28 patients). All patients were followed up for at least 15 months. Statistical analysis was carried using Student's t test and paired t test for quantitative data and Pearson's chi-square test for qualitative data.

RESULTS

The mean intraocular pressures (IOP) at the end of 15 months of follow-up in Groups I and II were 15.80+/-4.3 mmHg and 16.13+/-3.3 mmHg versus mean preoperative IOP of 28.63+/-2.74 and 28.60+/-2.44, p<0.0001, respectively. The difference in IOP control was significant only at 6 months of follow up (13.65+/-3.45 versus 15.98+/-4.05, p=0.041). The complications and failure were comparatively less in Group I.

CONCLUSIONS

Mini-trabeculectomy is a safe and effective alternative to conventional trabeculectomy in terms of IOP control. A modified tunnel incision employed in mini-trabeculectomy may be responsible for avoiding some of the complications.

Increase in weight induced by muraglitazar, a dual PPARalpha/gamma agonist, in db/db mice: adipogenesis/or oedema?

BACKGROUND AND PURPOSE

Muraglitazar, a dual PPARalpha/gamma agonist, caused a robust increase in body weight in db/db mice. The purpose of the study was to see if this increase in weight was due to oedema and/or adipogenesis.

EXPERIMENTAL APPROACH

The affinity of muraglitazar at PPARalpha/gamma receptors was characterized using transactivation assays. Pre-adipocyte differentiation, expression of genes for adipogenesis (aP2), fatty acid oxidation (ACO) and sodium reabsorption (ENaCgamma and Na+, K+-ATPase); haemodilution parameters and serum electrolytes were measured to delineate the role of muraglitazar in causing weight gain vis a vis rosiglitazone.

KEY RESULTS

Treatment with muraglitazar (10 mg kg(-1)) for 14 days significantly reduced plasma glucose and triglycerides. Reduction in plasma glucose was significantly greater than after similar treatment with rosiglitazone (10 mg kg(-1)). A marked increase in weight was also observed with muraglitazar that was significantly greater than with rosiglitazone. Muraglitazar increased aP2 mRNA and caused adipocyte differentiation in 3T3-L1 cells similar to rosiglitazone. It also caused a marked increase in ACO mRNA in the liver of the treated mice. Expression of mRNA for ENaCgamma and Na+, K+-ATPase in kidneys was up-regulated after either treatment. Increased serum electrolytes and decreased RBC count, haemoglobin and haematocrit were observed with both muraglitazar and rosiglitazone.

CONCLUSIONS AND IMPLICATIONS

Although muraglitazar has a better glucose lowering profile, it also has a greater potential for weight gain than rosiglitazone. In conclusion, muraglitazar causes both robust adipogenesis and oedema in a 14-day treatment of db/db mice as observed in humans.

Relevance of rodent models of intravenous MDMA self-administration to human MDMA consumption patterns

RATIONALE

Despite decades of research specifying harmful effects produced by 3,4-methylenedioxymethamphetamine (MDMA; a principal component of 'ecstasy' pills), young people (and adults) continue to use it. In an attempt to model human MDMA consumption patterns, preclinical investigators have sought to establish reliable patterns of intravenous MDMA self-administration in rodents.

OBJECTIVE

The objective of this report is to offer a critical review of published data (including our own novel findings) that reveal MDMA self-administration in rodents.

RESULTS

The data indicate that MDMA serves as a reinforcer in rodents, though the responses are not similar to those previously reported for psychostimulants (i.e., cocaine). Important differences between rodent models and human use patterns include frequency of dosing and dosage exposure, routes of administration, tolerance that develops to MDMA after repeated exposure, polydrug use in humans but not by rodents, limits on the repertoire of behaviors that can be exhibited by rodents undergoing IV self-administration procedures, and the question of neurotoxicity as it relates to models of self-administration.

CONCLUSIONS

While MDMA is not as potent a reinforcer as other drugs of abuse, the fact remains that young people and adults continue to use the drug, and therefore, additional research is needed to determine why drugs with low reinforcing effects continue to be abused.

Perioperative Erythropoietin Efficacy in Renal Transplantation

BACKGROUND

There is no consensus on the usage of erythropoietin in the immediate postoperative period to prevent anemia and delayed graft function.

METHODS

A retrospective case note audit of renal transplants included hemoglobin (Hb) and serum creatinine (Scr) values preoperatively as well as at days 7, 14, 30, 60, and 90. Patients were categorized as those receiving erythropoietin during the first 6 months posttransplant (Epo+ve) and those not receiving any erythropoietin (Epo-ve).

RESULTS

Hb decreased from 12.4 +/- 1.6 g/L preoperatively to 9.5 +/- 1.5 g/L at day 14 and then rose to 10.5 +/- 1.6 g/L at 1 month and 12.4 +/- 1.7 g/L at 3 months. There was no difference in absolute Hb values in three transplant groups. Scr decreased from 597.0 +/- 200.1 mmol/L preoperatively to 254.1 +/- 196.9 mmol/L at day 14 and continued to fall to 163.8 +/- 98.9 mmol/L at 1 month and 147.8 +/- 66.9 mmol/L at 3 months. There was no difference in absolute Hb values and delayed graft function in the three transplant groups.

CONCLUSION

With respect to anemia and delayed graft function, the use of erythropoietin in the first 3 months had little impact. We suggest that such an expensive medication may be safely omitted in the immediate postoperative period.

Reconstruction of iliac crest with rib to prevent donor site complications: A prospective study of 26 cases

BACKGROUND

The tricortical bone graft from the iliac crest are used to reconstruct the post corpectomy spinal defects. The donor iliac area defect is large and may give rise to pain at donor site, instability of pelvis, fracture of ilium, donor site muscle herniation or abdominal content herniation. Rib removed during thoracotomy was used by us to reconstruct the iliac crest defect.

MATERIALS AND METHODS

Twenty-six patients who underwent thoracotomy for dorsal spine corpectomy or curettage for various spinal pathologies from June 2002 to May 2004 were included in the study. After adequate decompression the spine was reconstructed by tricortical bone graft from iliac crest and reconstruction of the iliac crest was done with the rib removed for exposure during thoracotomy.

RESULTS

The mean follow up was 15 months. All patients had good graft incorporation which was evaluated on the basis of local tenderness and radiographs. One patient had graft displacement.

CONCLUSION

The reconstruction of iliac crest by rib is a simple and effective procedure to prevent donor site complications.

Treatment of Postcraniotomy Tension Pneumocephalus via Endoscopic Closure of the Nasofrontal Recess

Tension pneumocephalus can be a life-threatening complication following cranial surgery. We report a 14-year-old female who developed tension pneumocephalus following her most recent external approach to a recurrent pilocytic astrocytoma of the skull base and clivus. Because the risk of devascularization of the recently placed bone grafts was a concern, an endoscopic approach was chosen instead of a cramotomy. Endoseopic decompression was accomplished by opening the anterior ethmoid and frontal recess air cells after performing an uncinectomy. The nasofrontal recess areas were then packed from below with grafts of muscle and fascia lata. Follow-up magnetic resonance imaging (MRI) at three and eight months showed complete resolution of the intracranial air. At two-year follow-up, the patient is still asymptomatic. This case report presents treatment of tension pneumocephalus through endoscopic decompression and closure of the nasofrontal recess as a viable option if significant risks are associated with craniotomy and the status of the mucosa of the nasal frontal recess is known.

Pain relief following breast augmentation surgery: a comparison between incisional patient-controlled regional analgesia and traditional oral analgesia

BACKGROUND AND OBJECTIVES

Postoperative pain is a common problem following ambulatory breast augmentation surgery. This study was performed to compare standard of care (oral analgesics) with patient-controlled incisional regional analgesia (PCRA) for postoperative pain management at home for 48 h. A second aim was to compare the analgesic efficacy of ropivacaine 0.25% vs. 0.5%.

METHODS

Surgery was performed under local anaesthesia and monitored anesthesia care. Sixty adults (ASA 1-2) were randomized to one of two groups. Patients in Group PCRA could self-administer ropivacaine 0.25% 10 mL in the left breast and ropivacaine 0.5% in the right breast. Patients in Group T (tablets) received our standard of care treatment, i.e. oral paracetamol 1 g four times a day and oral ibuprofen 500 mg three times a day. Parameters measured included: analgesic requirements (in post-anesthesia care unit, PACU and post-discharge), pain intensity (visual analogue scale), patient satisfaction, global analgesia, side-effects, and quality of recovery.

RESULTS

Pain scores were significantly lower in Group PCRA compared to Group T at all time periods (P < 0.05). No differences were found in pain scores between the right and left breasts. Significantly more patients in Group T requested analgesics in the recovery unit (27 vs. 7; P = 0.001) and also at home (20 vs. 11; P < 0.02). More patients in the tablet group had nausea and vomiting (10 vs. 3; P < 0.05). Global analgesia on day 2 was significantly better in PCRA group; however, patient satisfaction was similar in both groups. More patients in the tablet group had sleep disturbance and woke up at night due to pain.

CONCLUSIONS

Pain relief after ambulatory breast augmentation is superior with incisional PCRA when compared to oral analgesic combination of paracetamol and ibuprofen. Incisional PCRA was associated with minimal side-effects and less sleep disturbance. There was no difference in the analgesic efficacy between ropivacaine 0.25% and 0.5%.

Serial quantitative diffusion tensor MRI of the term neonates with hypoxic-ischemic encephalopathy (HIE)

AIM

To determine the altered pattern of fractional anisotropy (FA) and mean diffusivity (MD) change in brain parenchyma in serially studied neonates with mild or moderate hypoxic ischemic injury (HIE) within 7 days after birth and again at the age of three months.

METHODS

Serial diffusion tensor imaging (DTI) was performed at two-time points in term neonates with mild (n = 7) and moderate (n = 10) HIE and age/sex-matched controls (n = 7). Neurodevelopmental outcome was assessed at the time of the 2nd study.

RESULTS

On comparing FA and MD changes over time using two-way analysis of variance between neonates with HIE and controls, we observed significant differences in age-related FA increase (p < 0.05) in anterior limb of internal capsule and periventricular white matter of parietal, occipital, and temporal lobes. Significant differences in age-related MD decrease (p < 0.05) was observed in the caudate nuclei, and temporal white matter among these groups. Significant positive correlation was observed between neurodevelopmental outcome and FA.

CONCLUSION

The results suggest that abnormal FA and MD values help in early and more accurate assessment of microstructural damage in HIE that may have predictive value for long-term neurofunctional outcome in these neonates.

Evidence-based review of treatment and follow up of pediatric patients with differentiated thyroid carcinoma

Childhood onset differentiated thyroid cancer (DTC) is distinct from the adult-onset disease being more aggressive at the time of initial evaluation with a higher risk category for disease recurrence; however, it is ultimately less lethal. International groups have outlined consensus statements detailing follow up and management guidelines for adult DTC, but since disease progression and markers are significantly different in childhood DTC compared to adults, management protocols may differ. Unfortunately, there is no consensus regarding the means of follow up, timing and management strategy regarding pediatric DTC. We performed an evidence-based review of DTC in children targeted to address the following questions: What is the most appropriate initial treatment? What is the goal of thyroid hormone replacement management? What is the approach to follow-up of childhood DTC? and, How should tumor recurrence/persistence be assessed and treated? We conducted a literature search using PubMed, Cochrane databases, guidelines from various international groups, and studies pertaining to pediatric DTC management and outcome in order to answer these questions. We suggest a pre-set algorithm and approach for the management of children with DTC according to our review.

Lower energy levels adequate for effective transcleral diode laser cyclophotocoagulation in Asian eyes with refractory glaucoma

PURPOSE

To study the treatment parameters for diode laser cyclophotocoagulation (DLCP) in Asian Indian eyes using laser energy titrated to clinical response.

METHODS

This prospective interventional longitudinal study included 66 eyes of 66 patients with varied aetiology refractory glaucoma, no previous cycloablation, and minimum 1 year follow-up. DLCP was performed using the Oculight Diode laser system IRIS( Medical Instruments Inc., CA, USA). Power used per spot was titrated according to the audible 'pops' indicating tissue microexplosion. The mean laser energy delivered, post-laser intraocular pressure (IOP) reduction, complications, and requirement of re-treatment in various subgroups were analyzed. Differences in energy delivered in each subgroup were assessed by analysis of variance with post hocBonferroni corrections. Linear regression analysis was used to identify possible predictive factors for failure of cyclodiode therapy.

RESULTS

The mean total energy delivered per eye was 87.80+/-31.8 J (range 105.4+/-36.8 J in neovascular glaucoma (NVG) to 61.5+/-8.8 J in uveitic glaucoma (P=0.134)). Mean pre treatment IOP was 36.4+/-10.7 mmHg, which reduced to 19.4+/-9.8 mmHg (P<0.001) at 1 week, and 15.6+/-6.6 mmHg at 1 year. At 1 year, 58 of 66 patients had IOP<22.0 mmHg (response rate 87.8%), and six patients had hypotony (success rate 78.8%). The uveitic glaucoma group had 100% success rate. NVG group required maximum re-treatments.

CONCLUSIONS

DLCP with a titrated energy protocol needs resulted in lower energy in Asian Indian eyes compared to that reported in literature, and different energy levels are needed for different diseases. 'Standard treatment parameters' for DLCP may be inappropriate for all diseases and all races.