Immunomodulatory activity of analog of muramyl dipeptide and their use as adjunct to chemotherapy of Leishmania donovani in hamster

In search of a potent immunomodulator to be used as an immunoprophylactic agent and as adjunct to chemotherapy against Leishmania infection, two analogs of muramyl dipeptide, viz. N.Ac-norMur-MeVal-D-isoGln (86/448) and N.AcMur-Acc-D-isoGln (89/729) were evaluated for desired activity. Effect of these peptides on cell mediated and humoral immunity was studied by immunizing the peptide treated mouse with sheep red blood cells (SRBC) and determining HA-titer, plaque forming cells assay and delayed type of hypersensitivity (DTH) response after 4-5 days. Both the peptides stimulated cell mediated immunity (CMI), humoral response as well as macrophage function in terms of super oxide anion (O2-) and nitric oxide (NO) generation. Mitogen induced lymphocyte proliferation and production of IL-2 and INF-gamma increased while that of IL-4 and IL-10 decreased by both the peptides showing a typical Th1 type response. After establishing the immunostimulatory activity, these peptides were evaluated for immunoprophylactic efficacy as well as for use as adjunct to chemotherapy with stibanate (SSG) against Leishmania donovani infection in golden hamster. These peptides were found quite effective in both the modes. In adjunct use the treatment may require lower dose of SSG and thereby reduce the chances of drug toxicity.

Survival analyses of breast cancer patients--the Shaukat Khanum Memorial experience

Seven hundred subjects with breast cancer malignancies were followed up in time from December 1994 to December 2002 to determine survival distributions between sub-groups of breast cancer patients who had undergone surgical resection of the tumor followed by adjuvant treatment. Tumor size, nodal status, and Estrogen Receptor (ER) status at the time of presentation were ascertained. Tumors were classified according to the TNM system of the American Joint Committee on Cancer (AJCC), sixth edition, and grouped into T1/T2 and T3/T4; lymph nodes were categorized as N0 (node-negative) and N1, N2, and N3 combined (node-positive). The endpoint of interest for disease-free survival was relapse, and for overall survival, it was death. The Wilcoxon statistics for testing the equality of disease-free survival distributions between groups of patients with tumor size greater than 5 versus less than or equal to 5 cm, node-positive versus node-negative, and ER-positive versus ER-negative were found to be statistically significant (p < 0.05). For overall survival, substantial differences were found between groups of patients stratified according to tumor diameter and nodal involvement, but none for ER status.

Laser in situ keratomileusis in a patient with presumed central cloudy corneal dystrophy of Francois

PURPOSE

To report a case of laser in situ keratomileusis (LASIK) surgery performed in a patient with likely central cloudy corneal dystrophy of Francois (CCDF).

DESIGN

Observational case report.

METHODS

A 48-year-old woman with likely CCDF had myopic LASIK to establish monovision. Outcome measures included visual acuity, manifest refraction, and slit-lamp examination.

RESULTS

At 5-year follow-up, the patient had uncorrected visual acuity of 20/100, J1, in the right eye (OD) and 20/20 in the left eye (OS), consistent with monovision correction. Manifest refraction was -1.50 OD and -0.25 OS postoperatively; after retreatment at 1 year for regression, the left eye remained stable over the subsequent 4-year period. Slit-lamp examination revealed no progression of corneal opacities in either eye.

CONCLUSIONS

LASIK may be safe and effective in patients with CCDF. Further observations of a greater number of patients are required to confirm these findings.

Esterification of fatty acids using nylon-immobilized lipase in n-hexane: kinetic parameters and chain-length effects

The esterification of long-chain fatty acids in n-hexane catalyzed by nylon-immobilized lipase from Candida rugosa has been investigated. Butyl oleate (22 carbon atoms), oleyl butyrate (22 carbon atoms) and oleyl oleate (36 carbon atoms) were produced at maximum reaction rates of approximately equal to 60 mmol h(-1) g(-1) immobilized enzyme when the substrates were present in equimolar proportions at an initial concentration of 0.6 mol l(-1). The observed kinetic behavior of all the esterification reactions is found to follow a ping-pong bi-bi mechanism with competitive inhibition by both substrates. The effect of the chain-length of the fatty acids and the alcohols could be correlated to some mechanistic models, in accordance with the calculated kinetic parameters.

Physiological aspects of pig-to-primate renal xenotransplantation

BACKGROUND

Few data exist on the physiological aspects of pig-to-primate renal xenotransplantation.

METHODS

Use of organs transgenic for human decay accelerating factor has allowed assessment of the metabolic and hormonal functions of these xenografts.

RESULTS

Porcine renal xenografts largely maintain plasma electrolyte homeostasis. An increase in proteinuria was detected that may result from graft injury. In contrast to allotransplantation a severe anaemia developed requiring recipient treatment with exogenous human erythropoietin.

CONCLUSIONS

Our experience provides qualified encouragement for the likely physiological compatibility of pig and primate species, but identifies areas where a xenograft may not match the performance of an allograft.

The use of the Hilbert transform in ECG signal analysis

This paper presents a new robust algorithm for QRS detection using the first differential of the ECG signal and its Hilbert transformed data to locate the R wave peaks in the ECG waveform. Using this method, the differentiation of R waves from large, peaked T and P waves is achieved with a high degree of accuracy. In addition, problems with baseline drift, motion artifacts and muscular noise are minimised. The performance of the algorithm was tested using standard ECG waveform records from the MIT-BITH Arrhythmia database. An average detection rate of 99.87%, a sensitivity (Se) of 99.94% and a positive prediction (+P) of 99.93% have been achieved against study records from the MIT-BITH Arrhythmia database. A detection error rate of less than 0.8% was achieved in every study case. The reliability of the proposed detector compares very favorably with published results for other QRS detectors.

Bilateral extracorporeal shock wave lithotripsy in a spinal cord injury patient with a cardiac pacemaker

OBJECTIVES

To review the precautions to be observed before and during extracorporeal shock wave lithotripsy (ESWL) in spinal cord injury (SCI) patients with a cardiac pacemaker and the safety of bilateral ESWL performed on the same day.

DESIGN

A case report of bilateral ESWL in a SCI patient with a permanent cardiac pacemaker.

SETTING

The Regional Spinal Injuries Centre, Southport, the Lithotripsy Unit, the Royal Liverpool University Hospitals NHS Trust, Liverpool, and the Department of Cardiology, Manchester Royal Infirmary, Manchester, UK.

SUBJECT

A 43-year-old male sustained a T-4 fracture and developed paraplegia with a sensory level at T-2. During the post-injury period, he developed episodes of asystole requiring implantation of a dual chamber (DDD) permanent pacemaker. Twenty-one months later, he developed a right ureteric calculus with hydronephrosis. A radio-opaque shadow was seen in the left kidney with no hydronephrosis. During right ureteric stenting, the ureteric stone was pushed into the renal pelvis. 1,500 shock waves were delivered to this stone on the right side, followed by ESWL to the left intra-renal stone with 1250 shock waves.

RESULTS

The patient tolerated ESWL to both kidneys. The pacemaker was reprogrammed to a single chamber ventricular pacing mode at 30 beats per minute with a reduced sensitivity during lithotripsy. There were no untoward cardiac events during or after lithotripsy. The serum creatinine was 45 micromol/l before lithotripsy and 44 micromol/l two weeks after ESWL.

CONCLUSION

SCI patients with a cardiac pacemaker may be able to undergo extracorporeal shock wave lithotripsy following temporary reprogramming of the pacemaker. Bilateral, simultaneous ESWL is safe in the vast majority of patients provided that there is no risk of simultaneous ureteric obstruction by stone fragments. However, it should be remembered that a decrease in renal function could occur following bilateral ESWL of renal calculi.

Factors contributing to the emergence of Escherichia coli O157 in Africa

In 1992, a large outbreak of bloody diarrhea caused by Escherichia coli O157 infections occurred in southern Africa. In Swaziland, 40,912 physician visits for diarrhea in persons ages >5 years were reported during October through November 1992. This was a sevenfold increase over the same period during 1990-91. The attack rate was 42% among 778 residents we surveyed. Female gender and consuming beef and untreated water were significant risks for illness. E. coli O157:NM was recovered from seven affected foci in Swaziland and South Africa; 27 of 31 patient and environmental isolates had indistinguishable pulsed-field gel electrophoresis patterns. Compared with previous years, a fivefold increase in cattle deaths occurred in October 1992. The first heavy rains fell that same month (36 mm), following 3 months of drought. Drought, carriage of E. coli O157 by cattle, and heavy rains with contamination of surface water appear to be important factors contributing to this outbreak.

Antisense oligonucleotide suppression of Na(+)/Ca(2+) exchanger activity in primary neurons from rat brain

An antisense (AS) oligodeoxynucleotide based on a conserved sequence in the three isoforms of the Na(+)/Ca(2+) exchanger (NCX) was used to decrease expression of this Ca(2+) transporter in primary neuronal cultures. Two AS oligo applications decreased NCX activity by approximately 40% within 12-24 h, and neither sense (S) or missense (MS) oligos altered NCX activity. The reduced NCX expression was confirmed by immunoblots and enzyme-linked immunosorbent assays (ELISAs). Resting [Ca(2+)](i) levels were 20% higher in AS-treated neurons and showed a slower return to baseline levels following activation of Ca(2+) influx by N-methyl-D-aspartate (NMDA). These results suggest that NCX plays a significant role in maintaining neuronal Ca(2+) homeostasis and in restoring baseline Ca(2+) levels following depolarization.

Long-term survival of nonhuman primates receiving life-supporting transgenic porcine kidney xenografts

BACKGROUND

Recently, there has been a resumed interest in clinical xenotransplantation using pig organs. However, no data are available yet regarding the capacity of porcine organs to sustain the life of a primate beyond the first month. We have attempted to obtain long-term survival of nonhuman primates using human decay-accelerating factor (hDAF) transgenic pig organs and an immunosuppressive strategy particularly aimed at neutralizing the humoral component of the immune response.

METHODS

hDAF transgenic or control kidneys were transplanted into 14 bilaterally nephrectomized cynomolgus monkeys (Macaca fascicularis) that underwent splenectomy and were immunosuppressed with cyclosporine A, cyclophosphamide, and steroids. All animals also received recombinant erythropoietin. Postoperatively, the primates were monitored daily. Laboratory evaluations included serum biochemistry, hematology, and measurements of hemolytic antipig antibodies. To assess the role of splenectomy in the control of humoral response, historical data were also used from a group of monkeys (n=7) that received the same immunosuppressive regimen and an hDAF transgenic porcine kidney but did not have splenectomy or receive recombinant erythropoietin.

RESULTS

This immunosuppressive approach obtained the longest survival time (78 days) described to date of a primate receiving a life-supporting porcine renal xenograft. Furthermore, four of nine animals in this series survived for 50 days or more. Most biochemical measurements in this study (including plasma urea, creatinine, sodium, and potassium concentrations) remained within normal ranges for several weeks in all of the longest-surviving animals.

CONCLUSIONS

Normalization of renal function (urea and creatinine) in primate recipients of porcine renal xenografts suggests that pig kidneys may be suitable for future clinical xenotransplantation. Additional immunosuppressive approaches, specifically designed to prevent humorally mediated immunological damage, should be explored to further prolong survival of primates that have received porcine xenografts.

Misdiagnosis of epilepsy: many seizure-like attacks have a cardiovascular cause

OBJECTIVES

We sought to investigate the value of cardiovascular tests to diagnose convulsive syncope in patients with apparent treatment-resistant epilepsy.

BACKGROUND

As many as 20% to 30% of epileptics may have been misdiagnosed. Many of these patients may have cardiovascular syncope, with abnormal movements due to cerebral hypoxia, which may be difficult to differentiate from epilepsy on clinical grounds.

METHODS

Seventy-four patients (33 men, mean age 38.9 +/- 18 years [range 16 to 77]) who were previously diagnosed with epilepsy were studied. Inclusion criteria included continued attacks despite adequate anticonvulsant drug treatment (n = 36) or uncertainty about the diagnosis of epilepsy, on the basis of the clinical description of the seizures (n = 38). Each patient underwent a head-up tilt test and carotid sinus massage during continuous electrocardiography, electroencephalography and blood pressure monitoring. Ten patients subsequently underwent long-term electrocardiographic (ECG) monitoring with an implantable loop recorder.

RESULTS

In total, an alternative diagnosis was found in 31 patients (41.9%), including 13 (36.1%) of 36 patients taking an anticonvulsant medication. Nineteen patients (25.7%) developed profound hypotension or bradycardia during the head-up tilt test, confirming the diagnosis of vasovagal syncope. One other patient had a typical vasovagal reaction during intravenous cannulation. Two patients developed psychogenic symptoms during the head-up tilt test. Seven patients (9.5%) had significant ECG pauses during carotid sinus massage. In two patients, episodes of prolonged bradycardia correlated precisely with seizures according to the insertable ECG recorder.

CONCLUSIONS

A simple, noninvasive cardiovascular evaluation may identify an alternative diagnosis in many patients with apparent epilepsy and should be considered early in the management of patients with convulsive blackouts.

Geographic variation of HIV infection in childbearing women with syphilis in the United States

OBJECTIVES

Substantial biologic and epidemiologic data indicate the importance of syphilis as a potential cofactor for sexual transmission of HIV infection, but few detailed data exist on the geographic covariation of these two important sexually transmitted infections.

DESIGN

HIV prevalence in childbearing women and primary and secondary (P&S) syphilis data from 29 states were examined to explore the importance of the epidemiology of syphilis as a factor in facilitating HIV transmission.

METHOD

The spatial relationship between P&S syphilis and HIV infection in the health districts of 29 states was analyzed and adjusted for demographic and socioeconomic factors such as racial composition, income, housing, education levels, and access to medical services using the 1990 US census, and geographic location.

RESULTS

In 29 states and the District of Colombia, 448 health districts, representing more than 75% of the US population, reported HIV prevalence rates for mothers' district of residence. The HIV seroprevalence ranged from 0 to 1258/10 000 in these health districts. The incidence of P&S syphilis from 1984-1994 in these districts ranged from 0 to 87/100 000. The P&S syphilis incidence was positively associated with the prevalence of HIV infection among childbearing women (P < 0.0001).

CONCLUSIONS

Syphilis that persists in communities in the United States appears to represent a 'sentinel public health event' reflecting risk for sexual HIV transmission. These findings, along with other biologic and epidemiologic information, reinforce the importance of syphilis as an indicator for targeting HIV prevention efforts generally, as well as syphilis control as a specific HIV-prevention strategy.

Haemodynamic effects of increasing angle of head up tilt

OBJECTIVE

To investigate the haemodynamic effects of varying the angle of head up tilt.

METHODS

20 healthy subjects (12 female, eight male; mean (SD) age 33.6 (8.4) years) underwent head up tilt for five minutes to each of four angles of tilt in random order, with a five minute rest period at the horizontal between each angle. Forearm blood flow was measured using intermittent occlusion mercury strain gauge plethysmography at two and five minutes. Subjects underwent continuous monitoring of heart rate, systolic blood pressure (SBP), and diastolic blood pressure (DBP) by Finapres and cardiac output and stroke volume by impedance cardiography. Each variable was measured at two and five minutes, averaged over the period of blood flow measurement.

RESULTS

Every haemodynamic variable at each angle was significantly different from supine values. Head up tilt produced progressive increases in heart rate (11-21%), SBP (12-21%), and DBP (20-33%) with increasing tilt angle. However, although 45 degrees produced significantly less haemodynamic effect, there were no significant differences for angles between 60 degrees and 90 degrees. Cardiac output fell on head up tilt by 17-20% and stroke volume by 28-34%, but increasing tilt angle produced no significant additional reduction in cardiac output and stroke volume because of increases in heart rate and vasoconstriction.

CONCLUSIONS

Angles < 60 degrees produce significantly less haemodynamic effects than steeper angles. Increasing tilt angle beyond 60 degrees produces no apparent additional effect on cardiac output or sympathetic tone. Increasing tilt angle beyond 60 degrees confers no additional orthostatic stress and may not affect the sensitivity and specificity of head up tilt testing as previously thought. Sixty degrees of tilt is a more practical angle for support of a syncopal patient and is recommended.

Effects of reactive oxygen species on brain synaptic plasma membrane Ca(2+)-ATPase

The regulation of free intracellular calcium [Ca2+]i is altered in neurons from the aged brain, possibly due to reductions in the activity of Ca2+ transporters. The plasma membrane Ca(2+)-ATPase (PMCA) plays a critical role in Ca2+ homeostasis, and its kinetic properties change in aged rat brain. These changes could be due to oxidative modification of PMCA as a result of age-related chronic oxidative stresses. The present studies were undertaken to determine the sensitivity of the neuronal PMCA to in vitro exposure of synaptic plasma membranes (SPMs) to reactive oxygen species (ROS). We examined the effects of three oxidants including peroxyl radicals generated by azo-initiators, 2,2'-Azobis 2-amidinopropane dihydrochloride (AAPH) and 4,4'-Azobis 14-cyanovaleric acid (ACVA), hydrogen peroxide (H2O2), and peroxynitrite (ONOO-). Synaptic plasma membranes briefly exposed to these oxidants were analyzed for functional and structural alterations in PMCA. Although all three oxidants led to significant loss of PMCA activity, the effect of ONOO- was the most potent, followed by peroxyl radicals and H2O2. Kinetic analysis of PMCA activity after oxidant treatment showed decreases in Vmax without significant changes in K(act). Immunoblots revealed oxidant-induced cross-linking of PMCA molecules that were partially reversed under reducing conditions and completely reversed with addition of urea. The PMCA appears to be very sensitive to inhibition by ROS and hence may be a target of oxidative stress in the aging brain. Reduction in its activity may contribute to age-related alterations in neuronal [Ca2+]i regulation.

Head-up tilting is a useful provocative test for psychogenic non-epileptic seizures

Differentiating psychogenic non-epileptic attack disorder (NEAD) from true epilepsy is difficult. This often results in a misdiagnosis and unnecessary and ineffective treatment. Prolonged EEG/video recording is the most sensitive tool for differentiating NEAD from epilepsy, but is costly and therefore limited in availability. Provocative tests, particularly the use of saline injection, can reduce the length of monitoring but give rise to ethical dilemmas. This study assesses the value of head-up tilt testing as a provocative test for NEAD. Twenty-one patients (17 female, mean age 34.6 +/- 11.5 years) with recurrent seizure-like episodes and a clinical diagnosis of NEAD were studied. Patients were tilted to 80( composite function )on an electric tilt table with footplate support for up to 45 minutes during continuous ECG, EEG and blood pressure monitoring. Seventeen patients (81%) experienced typical symptoms (non-epileptiform limb shaking in 15 patients, absence in one patient, myoclonic jerking in one patient) during head-up tilt without significant EEG abnormalities or haemodynamic changes. The mean time to onset of seizure-like activity was 13.2 +/- 11 minutes (range 0-31 minutes). No patients suffered injury or any other significant side-effect. Provocative testing using suggestion and head-up tilt is a sensitive tool for diagnosing NEAD and represents a safe, simple and inexpensive outpatient technique for investigating patients with suspected NEAD.

Accurate diagnosis of convulsive syncope: role of an implantable subcutaneous ECG monitor

Convulsive syncope due to transient bradycardia is recognized as a cause of treatment-resistant seizures. However, the diagnosis may be difficult to make with conventional electrocardiographic devices if attacks are infrequent. We present a case of apparent epilepsy in which a new implantable electrocardiographic event recorder (the 'Reveal' insertable loop recorder) was used to show that attacks were caused by prolonged asystole of up to 36 s in duration. The insertable loop recorder may have an important role in the investigation of patients with treatment-resistant seizures, particularly where there is a strong suspicion of an underlying cardiac arrhythmia.