Volterra filter modelling of non-linear system using Artificial Electric Field algorithm assisted Kalman filter and its experimental evaluation

The main objective of this paper is to improve the identification efficiency of non-linear systems using the Kalman filter (KF), which is optimised with the Artificial Electric Field (AEF) algorithm. The conventional KF suffers from the proper tuning of its parameters, which leads to a divergence problem. This issue has been solved to a great extent by the meta-heuristic AEF algorithm assisted Kalman filter (AEF-KF). This paper proposes three steps for the identification of the systems while solving the problem as mentioned above. Firstly, it converts the identification model to a measurement problem. Next, the AEF algorithm optimises the KF parameters by considering the fitness function with the KF equations. The third step is to identify the model using conventional KF algorithm with the optimised KF parameters. To evaluate the performance of the proposed method, parameter estimation error, mean squared error (MSE), fitness (FIT) percentage, statistical information and percentage improvement are considered as the performance metrics. To validate the performance of the proposed method, five distinct non-linear models are identified with the Volterra model using KF and the AEF-KF techniques under various noisy input conditions. Besides, the practical applicability of the proposed approach is also tested on two non-linear benchmark systems using experimental data sets. The obtained simulation results confirm the efficacy and robustness of the proposed identification method in terms of the convergence speed, computational time and various performance metrics as compared to KF, Kalman smoother (KS) which is optimised using different state-of-the-art evolutionary algorithms and also other existing recently reported similar types of stochastic algorithms based approaches.

Pectoral-intercostal fascial plane block in chronic post-sternotomy pain

Persistent poststernotomy pain (PSP) is a well-known entity following cardiac surgery done with midline strenotomy. The severity of pain is usually mild to moderate in the majority of the patients. However, a small percentage of patients develop severe and persistent pain and need aggressive treatment. Our patient, a 63-year-old lady developed chronic severe parasternal pain following coronary artery bypass graft surgery. As multiple medications did not relieve her pain effectively, we did an ultrasound-guided pectoral-intercostal fascial plane block to which she responded with excellent and long-lasting pain relief. This is the first such case report of the use of this novel block technique for treating PSP.

Evaluation of Virucidal Efficacy of Cold Plasma on Bacteriophage Inside a Three-Layered Sterilization Chamber

Traditional disinfection methods against pathogens have numerous shortcomings, and inventive methods like cold plasma are required for virus inactivation. Here, an atmospheric pressure 13.56 MHz radio-frequency hollow cathode (RF–HC) cold plasma device has been used to build a cold plasma sterilization device, and its virucidal activity is assessed against P2 bacteriophage, a model surrogate for pathogenic viruses. The heart of this device contains a three-layered sterilization chamber which is a rectangular parallelopiped of 42 × 32 × 30 cm³. Optimization experiments were performed to make each corner of this chamber completely virus free after cold plasma treatment. This two-pronged study was conducted to establish the requirement of minimum vol. % H₂O₂ in minimum time for the complete elimination of phages inside this sterilization chamber even when plasma is not in the direct line of sight. In initial experiments, the effect of the direct plasma line of sight was seen as the top and bottom layers showing less phage killing as compared to the middle of the sterilization chamber. Complete sterilization of bacteriophage, in all the three layers inside the sterilization chamber, was achieved by plasma treatment with 6% H₂O₂ for 10 min in 80 watts of plasma operating power. It was also seen that 6% H₂O₂ mist alone is not sufficient to provide a high degree of sterilization, and normal water mist combined with cold plasma can provide a higher level of sterilization at each corner of the chamber.

Stellate ganglion block as rescue therapy in drug-resistant electrical storm

Electrical storm or incessant ventricular tachycardia is a life-threatening condition and is associated with high morbidity and mortality. Often patients respond to traditional anti-arrhythmia treatment. However, some patients are resistant to the drug therapy and thus, pose huge challenges in effective management. Though stellate ganglion block has been found to be effective in treating patients with electrical storm, it is still under-utilized. In this case report, we successfully managed to revert the drug-resistant arrhythmia to sinus rhythm after ultrasound-guided stellate ganglion block. Earlier utilization of the block can possibly provide effective treatment in drug-resistant ventricular arrhythmias and prevent morbidity and mortality.

Physical Frailty Phenotype and Depression are Associated with More Severe Disease in Older Subjects Presenting with Acute Coronary Syndrome

Objective

The primary objective was to determine the occurrence of frailty in elderly patients presenting with the acute coronary syndrome (ACS). The secondary objective was to study the association between the deficits in health with the severity of ACS at presentation among them.

Methods

A cross-sectional study conducted in the Departments of Medicine, Community Medicine and Biochemistry in a tertiary care teaching hospital, Delhi, India between November 2014 and April 2016. Patients (≥60 years age) presenting with any one of the spectra of ACS (STEMI, UA, NSTEMI) and giving informed written consent were assessed for frailty and health deficits using questionnaires. ACS assessed by ECG within 24 h and other relevant investigations. Appropriate statistical tests of significance like the Chi-square test were used and correlation coefficients were analyzed. A value of P < 0.05 was considered significant.

Results

Seven risk factors apart from old age were studied, in which smoking and dyslipidemia played a major role. 44% of the subjects were frail with the range of frailty scores between 3 and 5. Every one-unit increase in hemoglobin was associated with a reduction in the odds (OR 0.72) for being frail. No association was noted between the severity of ACS and established risk factors like smoking, hypertension, diabetes, family history of CAD, increased waist circumference, dyslipidemia, and male gender. On multivariable linear regression, presence of frailty and depression were associated with severe disease.

Conclusions

Nearly one in two patients presenting with ACS were found frail. Depression and frailty were associated with poorer ejection fraction and severe disease. Correction of anemia and improvement of low-normal hemoglobin levels could reduce frailty and in-turn improve outcomes in ACS.

Cold Plasma: Clean Technology to Destroy Pathogenic Micro-organisms

Atmospheric pressure cold plasma is a promising technology in fighting pathogenic micro-organisms. In times of Covid-19 pandemic, it was decided to modify two types of cold plasma devices to study their effectiveness in the killing of pathogenic micro-organisms. These studies have shown that both the devices are efficient in this purpose. While pencil like microwave based device can destroy Aeromonas bacteria and its bacteriophage from 6 cm distance in 2 min, the larger (~ 40 cm2) RF plasma based device could do the similar killing ability for the larger possible area in 4 min. Optical Emission Spectroscopy (OES) studies revealed that both these devices produce OH radicals which helped in the destruction of both bacteria and its bacteriophage. With suitable modifications, these devices, especially the larger area device may even be implemented for the elimination of Covid-19 affected wards of hospital without using any sensitive chemical process.

As the Nasal Spine Goes, So Goes the Septum

INTRODUCTION

"As the septum goes, so goes the nose". A well-known phrase by Maurice Cottle forms the pillar of septoplasty. Since the inception of septal surgeries, numerous methods of septoplasty have been described. But, if not performed meticulously, may lead to deformity. For a successful surgery, understanding the anatomy and addressing the anterior nasal spine and maintaining the tip integrity is vital.

AIM

To study the outcomes of "ROUND ABOUT technique" to correct deviated nasal septum which focuses on the importance of anterior spine and hence maintain the tip integrity.

MATERIALS AND METHODS

This was a prospective, single-centre outcome study of 35 patients with symptomatic nasal obstruction. Here, we describe a method of elevating the mucoperichondrial and mucoperiosteal flaps bilaterally, without transecting the quadrilateral cartilage of the septum. The Sino Nasal Outcome Test-22 (SNOT-22) Questionnaire was administered pre-operatively and after 3 months following surgery. The post-operative follow-up period ranged from 3 to 6 months (mean= 4.5 months) to evaluate the functional and aesthetic outcomes of the performed procedure.

RESULTS

A total of 35 patients underwent surgery by this technique who presented with deviated nasal septum and variable degrees of nasal obstruction. To assess the statistical outcome, Paired t-test was applied. Mean SNOT-22 scores decreased significantly from 40.02 pre-operatively to 18.65 three months after surgery. The results sustained after 6 months (p-value <0.0001), 85% of these patients had improved breathing post-operatively and none of the patients complained any aesthetic criticisms. The patients were content and the requirement of medications post-operatively were minimal.

CONCLUSION

The ROUND ABOUT technique is a very effective and safe method in correcting the septal deviations especially the ones with caudal or dorsal deflections. It also helps in maintaining the tip integrity and addressing the anterior nasal spine. It avoids the complications of conventional septoplasty.

Delay and misdiagnosis of basidiobolomycosis in tropical South India: case series and review of the literature

Basidiobolomycosis caused by Basidiobolus ranarum is a rare infection of the subcutaneous tissues in immune-competent patients which occurs predominantly in children and young adults. Primary physicians often misdiagnose the condition owing to its slow, painless, relentless growth, absence of response to antibiotics and anti-inflammatory drugs and unfamiliarity with this lesion. All cases of subcutaneous basidiobolomycosis in children aged between 1 and 12 years presenting at a tertiary hospital in Pondicherry over a period of 4 years (2007-2011) were analysed. Eight cases were seen and confirmed by histopathology and microbiology. Referral diagnoses varied widely from chronic abscess to tuberculosis to malignancy, including testicular tumour. Lesion sites include the gluteal region, thigh and scrotum (extremely rare). Four weeks of oral itraconazole in seven children and fluconazole (5 mg/kg) in one cured them completely. During follow-up for over 1 year, no recurrence or new lesions were noted. Basidiobolomycosis is a rare, often misdiagnosed infection in children which responds well to triazole antifungals such as itraconazole and fluconazole.

An efficient identification approach for stable and unstable nonlinear systems using Colliding Bodies Optimization algorithm

This paper presents an efficient approach to identify different stable and practically useful Hammerstein models as well as unstable nonlinear process along with its stable closed loop counterpart with the help of an evolutionary algorithm as Colliding Bodies Optimization (CBO) optimization algorithm. The performance measures of the CBO based optimization approach such as precision, accuracy are justified with the minimum output mean square value (MSE) which signifies that the amount of bias and variance in the output domain are also the least. It is also observed that the optimization of output MSE in the presence of outliers has resulted in a very close estimation of the output parameters consistently, which also justifies the effective general applicability of the CBO algorithm towards the system identification problem and also establishes the practical usefulness of the applied approach. Optimum values of the MSEs, computational times and statistical information of the MSEs are all found to be the superior as compared with those of the other existing similar types of stochastic algorithms based approaches reported in different recent literature, which establish the robustness and efficiency of the applied CBO based identification scheme.

Isolated Langerhans Histiocytosis in Thyroid: Thyroidectomy or Chemotherapy?

Langerhans cell histiocytosis (LCH) is a rare disorder of mononuclear phagocytic system whose clinical presentation varies from the localised involvement of a single bone to a widely disseminated disease. Langerhans cell histiocytosis rarely involves the thyroid gland and isolated involvement of thyroid is even rarer. We report a case of an eight-year-old male child diagnosed with Langerhans cell histiocytosis limited to thyroid gland with review of literature. Should thyroidectomy be done or proceed with chemotherapy? Our case report raises this question with a note on the role of 18 fluoro deoxy glucose positron emission tomography-computed tomography in the management of the same.

Survivin siRNA increases sensitivity of primary cultures of ovarian cancer cells to paclitaxel

PURPOSE

This aim of this study was to use ovarian cancer cells shed in ascitic fluid to establish primary cultures and subsequently use it to detect drug resistance to paclitaxel. Survivin siRNA was used to down regulate survivin expression and effect on paclitaxel resistance was also evaluated.

METHODOLOGY

Ascitic fluid along with corresponding primary tumor tissue was collected from twenty untreated epithelial ovarian cancer patients. Ten primary cultures were established from ascites obtained from untreated ovarian cancer patients in MCDB 105 and M199 medium (ratio 1:1). Knockdown of survivin was done using siRNA and sensitivity to paclitaxel was evaluated by MTT assay.

RESULTS

Grape-like clusters of ovarian cancer cells present in ascites attached and gave a characteristic cobble stone appearance. Treatment with survivin siRNA resulted in a fivefold decrease in survivin expression in primary cultures. Survivin siRNA treatment significantly increased the sensitivity of the primary ovarian cancer cell cultures to paclitaxel.

CONCLUSION

Ascitic cancer cells reflect the molecular profile of tumor and can be used to diagnose resistance to chemotherapy. This study also establishes that high survivin expression is also responsible for resistance to paclitaxel.

Non-haematopoietic malignancies metastasing to the bone marrow: a 5 year record-based descriptive study from a tertiary care centre in South India

INTRODUCTION

Bone marrow involvement by a non-haematological malignancy gives an opportunity to identify the lodgement, invasion of metastatic cells and the response of the host to the tumor cells. The study was undertaken to assess the involvement of bone marrow with non-haematopoietic malignancies and its significance in establishing primary diagnosis in clinically unsuspected cases.

MATERIALS AND METHODS

This was a descriptive study which included record review of the departmental archives for the last five years (January 2007 to December 2011). Eighty four cases were studied; which included clinically diagnosed non-haematological malignancy for staging or symptomatic cytopenias/bony lesions (group 1, n = 63), clinically suspected bone marrow metastasis of unknown primary malignancy due to symptomatic cytopenias/bony lesions (group 2, n = 07) and clinically unsuspected malignancy with incidentally detected bone marrow metastasis (group 3, n = 14).

RESULTS

Bone marrow metastases of solid tumors were identified in 23 cases (27.3%) which included 9 cases from group 1, 14 cases from group 3 and nil in group 2. Of the 14 cases in group 3, in 12 cases a definitive diagnosis could be made by correlating clinicoradiological findings with morphology and immunohistochemistry. The most common tumor in pediatric cases were neuroblastoma and Ewing's sarcoma (40%) and in adult's adenocarcinoma of gastrointestinal tract (30.7%) was the commonest.

CONCLUSION

Bone marrow metastasis can masquerade as a primary haematopoietic disorder; however its detection has both therapeutic and prognostic significance. Immunohistochemistry is a useful adjunct to morphology in reaching a definitive diagnosis.

Collective Animal Behaviour Based Optimization Algorithm for IIR System Identification Problem

In this paper a novel optimization technique which is developed on mimicking the collective animal behaviour (CAB) is applied to the infinite impulse response (IIR) system identification problem. Functionality of CAB is governed by occupying the best position of an animal according to its dominance in the group. Enrichment of CAB with the features of randomness, stochastic and heuristic search nature has made the algorithm a suitable tool for finding the global optimal solution. The proposed CAB has alleviated from the defects of premature convergence and stagnation, shown by real coded genetic algorithm (RGA), particle swarm optimization (PSO) and differential evolution (DE) in the present system identification problem. The simulation results obtained for some well known benchmark examples justify the efficacy of the proposed system identification approach using CAB over RGA, PSO and DE in terms of convergence speed, unknown plant coefficients and mean square error (MSE) values produced for IIR system models of both the same order and reduced order.

A Novel Firefly Algorithm for Optimal Linear Phase FIR Filter Design

Optimal digital filter design in digital signal processing has thrown a growing influence on communication systems. FIR filter design involves multi-parameter optimization, on which the existing optimization algorithms do not work efficiently. For which different optimization techniques can be utilized to determine the impulse response coefficient of a filter and try to meet the ideal frequency response characteristics. In this paper, FIR low pass, high pass, band pass and band stop filters have been designed using a new meta-heuristic search method, called firefly algorithm. Firefly Algorithm is inspired by the flash pattern and characteristics of fireflies. The performance of the designed filters has been compared with that obtained by real coded genetic algorithm (RGA), standard PSO and differential evolution (DE) optimization techniques. Differential evolution (DE) is already one of the most powerful stochastic real-parameter optimization algorithms in current use. Here the firefly algorithm (FA) technique has proven a significant advantage. For the problem at hand, the simulation of designing FIR filters has been done and the simulation results demonstrate that Firefly algorithm is better than other relevant algorithms, not only in the convergence speed but also in the performance of the designed filter.

Niemann-Pick disease, type B with TRAP-positive storage cells and secondary sea blue histiocytosis

We present 2 cases of Niemann Pick disease, type B with secondary sea-blue histiocytosis. Strikingly, in both cases the Pick cells were positive for tartrate resistant acid phosphatase, a finding hitherto described only in Gaucher cells. This report highlights the importance of this finding as a potential cytochemical diagnostic pitfall in the diagnosis of Niemann Pick disease.

Niemann-Pick disease, type B with TRAP-positive storage cells and secondary sea blue histiocytosis

We present 2 cases of Niemann Pick disease, type B with secondary sea-blue histiocytosis. Strikingly, in both cases the Pick cells were positive for tartrate resistant acid phosphatase, a finding hitherto described only in Gaucher cells. This report highlights the importance of this finding as a potential cytochemical diagnostic pitfall in the diagnosis of Niemann Pick disease.

Evaluation of eosin-5-maleimide flow cytometric test in diagnosis of hereditary spherocytosis

A flow cytometry-based test using eosin-5-maleimide (EMA) dye was used for diagnosis of hereditary spherocytosis (HS). The mean fluorescence intensiy (MFI) of EMA tagged erythrocytes is lower in HS than that in other hemolytic and nonhemolytic anemias. We enrolled 114 subjects comprising 20 confirmed HS, 20 suspected HS/hemolytic anemia (HA), 20 normal controls, 20 other hemolytic anemias [13 autoimmune hemolytic anemia, three congenital dyserythropoietic anemia (CDA), one pyruvate kinase deficiency, two microangiopathic hemolytic anemia], 18 microcytic anemia and 16 macrocytic anemia cases. All samples were subjected to flow cytometry as per standard protocol. The mean MFI of normal control subjects was 11 861.5 (SD 883.5) and of confirmed HS was 7949.3 (SD 1304.1). Using this test, of 20 patients suspected to be HS/HA but with no confirmatory diagnosis, eight patients were diagnosed as HS. Using logistic regression analysis, the optimum cut-off MFI value between HS and normal controls was 10126. The area under the ROC curve was 0.99. The statistical significance of MFI values was obtained by t-test or Wilcoxon rank sum test as applicable. Compared with normal controls, the MFI values in HS were lower and in megaloblastic anemia were higher which was statistically highly significant (P<0.01), and the MFI values in CDA were lower which was statistically significant (P<0.05). False-positive values were obtained in three cases of AIHA and two cases of CDA. The sensitivity and specificity was 96.4% and 94.2% respectively. The EMA-based flow cytometry test is a highly sensitive and specific method for the diagnosis of HS.

Multi-organ failure due to Mycobacterium tuberculosis and Aspergillus flavus infection after allogeneic bone marrow transplantation

Mycobacterium tuberculosis (MT) is a serious, but rare infectious complication after allogeneic bone marrow transplantation (BMT). We describe a case of fatal sepsis due to MT and Aspergillus flavus after allogeneic BMT for Aplastic Anemia. The diagnosis was made on bone marrow biopsy and asitic fluid culture. Broadspectrum antituberculous and Amphotericin B therapy was started immediately after diagnosis. The patient developed severe hypoxia and finally died of multi-organ failure. Rapid progression of mycobacterial infection as well as fungal infection should be considered in patients post BMT with unexplained fever, particularly in patients from endemic areas.

Anti-cancer gene expression profile of curcumin identifies new therapeutic targets in squamous cell lung carcinoma in vitro

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Background: Lung cancer is notorious for early metastasis and very high mortality, worldwide. Curcumin, a chemopreventive has also shown chemotherapeutic potential but its mechanisms are still not well understood. In this study, the genes targeted by Curcumin were investigated to identify new targets for the therapy of squamous cell lung carcinoma (SCC) in vitro. Methods: Lung squamous cell carcinoma cells (H520) were cultured in DMEM with 10% FCS. They were treated with Curcumin (25μM) for 24 hours. Apoptosis was detected by morphological examination, MTT assay, flowcytometry and TUNEL assay. Microarray analysis of gene expression profiles on curcumin treatment was done. Real time quantitative RT-PCR confirmed the results. Results: Curcumin (25μM for 24 hours) caused 29.8 ± 2.1% cytotoxicity (MTT assay). Apoptosis was corroborated by flowcytometry (23.7 ± 1.4%) and TUNEL (21.6 ± 1.8%). Using microarray analysis, 34 genes were seen to be upregulated and 31 genes downregulated after curcumin treatment. Several apoptosis related genes were upregulated including GADD45a (3.36 fold), transcription factor Egr-1 (2.2 fold) and Peroxiredoxin-I (2 fold). In addition, Angiopoietin-2 (Ang-2), an angiogenic factor that promotes angiogenesis and tumor invasion was downregulated (1.7 fold). Real time quantitative RT-PCR confirmed the results. Conclusions: This study helps to identify novel putative intervention sites as targets for curcumin in the therapy of squamous cell lung carcinoma (SCC) in vitro and can contribute to better understanding of lung tumorigenesis and anticancer therapy.

No significant financial relationships to disclose.

Isolated perfusion of pancreas with mitomycin C

The current treatment of pancreatic cancer with resection and/or radiation is considered unsatisfactory because of a high incidence of failure and a moderate incidence of complications. A sizable number of these patients present with localized or regional disease. Regional high-dose chemotherapy, such as with isolated perfusion, may offer an alternative therapy with low treatment-related morbidity and mortality and better end results in this group of patients. In an effort to develop such a treatment modality, we evaluated the pharmacokinetics and toxicity of mitomycin C (MMC) during isolated perfusion of pancreas in a canine model. From this study, it appears that a dose of 0.25 mg MMC/kg body weight is most suitable for isolated perfusion of pancreas at 39 degrees C, maintaining flow rate and pressure within physiologic range. Isolated perfusion with a dose of 0.25 mg/kg body weight has very mild short- and long-term toxicities and markedly increases drug delivery to the pancreas, duodenum, and peripancreatic lymph nodes, making it the most suitable dose for possible clinical application.

Plasma ultrafiltration as successful therapy of rabbit VX-2 carcinoma

It has been demonstrated that tumor-bearing animals elaborate a low molecular weight (less than 10,000 daltons) factor capable of inhibiting in vitro lymphocyte function. It was postulated that removal of this factor would have a favorable effect on host immune response that would translate into improved tumor control. A study was conducted in rabbits bearing the VX-2 carcinoma. Ultrafiltration (UF) was performed 10 days following IV tumor inoculation. UF was achieved by passing blood through an Amicon Diafilter (molecular weight cutoff 10 kD) positioned between the arterial and venous cannulae after heparinization. Two plasma volumes of ultrafiltrate were removed with continuous saline replacement. Two groups of animals received the nonspecific immunoadjuvant, Detox, at time of therapy. Survival in the UF group (N = 9) was compared to untreated tumor-bearing animals (N = 10), sham-operated animals (N = 6), animals receiving Detox (N = 7), and animals receiving UF plus Detox (N = 6). UF imparted a survival advantage when compared to controls (mean 35 days vs. 25 days, P less than .01). The sham group had survival identical to controls. Detox alone conferred minimal survival advantage (mean 29 days, P greater than .05). However, UF + Detox demonstrated maximal survival benefit (mean 40 days, P less than .01). We conclude that UF is an effective anticancer modality in this preclinical model. This study suggests that efforts aimed at eliminating suppressor molecules in cancer patients may be of benefit, especially when combined with biological response modifiers such as Detox.

Pharmacokinetics of hexamethylmelamine in intralipid following hepatic regional administration in rabbits

Hexamethylmelamine (HMM) is a cytotoxic agent demonstrated to have broad antitumor activity. Poor solubility in aqueous media has precluded significant evaluation of parenteral administration of this drug. A formulation of HMM dissolved in Intralipid has demonstrated excellent tolerance following parenteral administration. The goal of this study was to evaluate the pharmacology of HMM in Intralipid following hepatic regional administration. The routes of administration were intraarterial via the hepatic artery with and without arterial occlusion, i.v. via the portal and jugular veins, and i.p. All animals received a total dose of 10 mg HMM/kg of body weight. Hepatic extraction of HMM was most evident via the portal vein (PV) route [AUC(PV)/AUC(i.v.) = 0.5; P less than 0.05]. Lower plasma levels and areas under the curve (AUCs) were observed for the hepatic artery and hepatic artery-stop flow groups when compared to i.v., but the difference was not significant. Administration i.p. yielded low plasma levels but a very long half-life (88 min). Hepatic tissue levels were highest in the group receiving HMM by the hepatic artery-stop flow route. We conclude that the HMM-Intralipid mixture is well tolerated, that HMM is extracted to a significant degree by the liver following PV administration, and that an i.p. installation of HMM-Intralipid results in prolonged plasma drug levels. This preclinical study supports further efforts at evaluation of parenteral administration of the HMM-intralipid mixture.

Sequential elaboration of lymphocyte-enhancing and -suppressing factors in the sera of tumor-bearing animals

Serum-mediated impairment of lymphocyte function was studied in an animal model. Sprague-Dawley rats inoculated intraperitoneally or subcutaneously with the Walker 256 carcinoma underwent sequential sampling of blood. The effect of these serum samples upon phytohemagglutinin-induced blastogenesis of normal rat splenocytes was monitored in an assay utilizing incorporation of (3H)-thymidine. The effect of serum samples from both the subcutaneously and the intraperitoneally inoculated tumor-bearing animals was biphasic. Early on, serum enhanced blastogenesis and later suppressed blastogenesis. Separation of sera into high and low molecular weight components by ultrafiltration demonstrated the enhancing activity to reside in the high molecular weight fraction. The enhancing activity of sera decreased over time from tumor inoculation. Conversely, suppressor activity increased over time from tumor inoculation. This study demonstrated that suppressor activity of sera obtained from animals with advanced tumors is the result of the lack of enhancing activity coupled with the elaboration of suppressor activity.

The pharmacokinetics of cisplatin in experimental regional chemotherapy

Cisplatin (DDP) is attractive for use in regional chemotherapy because of its tendency for protein binding. A study of regional chemotherapy was conducted in rabbits bearing the VX-2 carcinoma. Modes of therapy examined were intravenous (IV), intra-arterial (IA), IA with stopflow, IA with outflow occlusion, and isolation-perfusion (I-P). Each mode was evaluated by examining the pharmacokinetics of DDP in systemic and regional administration and measuring tissue concentrations of DDP. It was observed that the systemic exposure to DDP was significantly less for IA with outflow occlusion and I-P when compared to IV, IA, or IA with stopflow occlusion (P = 0.003). Tumor concentrations were highest with IA infusion with outflow occlusion (P = 0.002) and IA stopflow occlusion (P = 0.03). Tumor tissue concentrations were always higher than adjacent muscle DDP concentrations. The authors conclude that significant pharmacologic advantage can be demonstrated for certain modes of DDP administration in this rabbit model, and that these promising results should be followed by clinical trials.

The pharmacology of hepatic regional administration of cisplatin in a rabbit model

The pharmacology of hepatic regional administration of CisplatinR (DDP) was examined in a rabbit model. Routes and modes of administration were: IV, hepatic arterial infusion (HAI), HAI with stopflow, HAI with microembolic material [collagen for embolization (CFE)], and portal vein (PV). DDP was rapidly administered, blood samples were drawn over 45 minutes, and hepatic tissue was obtained. Filterable plasma DDP levels were measured by HPLC. Hepatic DDP levels were determined by atomic absorption spectroscopy. All modes of regional administration yielded significantly higher hepatic DDP levels when compared to tissue levels following IV administration. Only the PV and HACFE routes resulted in significantly less systemic drug exposure (AUC) when compared to IV administration. These data indicate a relative pharmacologic advantage of 1.8 for HAI, 3.4 for PV, 1.8 for HAI stopflow, and 4.3 for HACFE compared to IV DDP administration. This pre-clinical study demonstrates substantial pharmacologic advantage for PV and HACFE routes of DDP administration and suggests that clinical trials based on this information be considered.

Pharmacokinetics of 5-fluorouracil in rabbits in experimental regional chemotherapy

The goal of this study was to identify the mode(s) of regional administration of 5-fluorouracil (5-FUra) with the greatest pharmacological advantage in an animal model. Parameters examined were the amount of systemic exposure to 5-FUra and plasma and tissue levels of 5-FUra. Anesthetized New Zealand white rabbits bearing a VX-2 carcinoma in the thigh received 5-FUra (20 mg/kg body weight) by the following routes: i.v., intraarterial (i.a.), i.a. with stopflow, i.a. with outflow occlusion, and isolation perfusion (IP). Serial venous blood samples were obtained prior to and after drug administration for a total of 45 min. A similar sampling of the perfusion circuit was conducted in those animals undergoing IP. At the end of the sampling period tumor and adjacent normal muscle were obtained. Plasma and tissue levels of 5-FUra were determined by a high pressure liquid chromatographic method. It was observed that systemic exposure to 5-FUra was identical for the i.v., i.a., i.a. with stopflow, and i.a. with outflow occlusion groups. Systemic exposure to 5-FUra in the IP group was only 0.30 of that observed for the i.a. group. Tissue 5-FUra levels in the i.v., i.a., and i.a. with stopflow groups were low and comparable to one another. Tissue levels of the 5-FUra were significantly higher in the i.a. with outflow occlusion and IP groups. We conclude that only selected forms of regional administration of 5-FUra offer pharmacological advantage when compared to systemic administration.