Oxidative Pyrolysis and Postpyrolytic Derivatization Techniques for the Total Analysis of Maillard Model Systems: Investigation of Control Parameters of Maillard Reaction Pathways

Factors that regulate various pathways of Maillard reaction leading to aroma, color, or carcinogen generation have not been identified, due to the difficulties associated with analyzing complex reaction mixtures. In particular, the role played by oxidation in directing aromagenic, chromogenic, or carcinogenic pathways is not well understood. In order to overcome the analytical difficulties, novel Py-GC/MS-based methodologies were developed to analyze volatile and nonvolatile residues of Maillard reaction products generated from the same model system under air or helium atmosphere. The analysis of nonvolatiles was achieved through a postpyrolytic in situ derivatization technique using hexamethyldisilazane, and pyrolysis under air was achieved through modification of the GC equipped with sample concentration trap to allow gas stream switching and subsequent isolation of the pyrolysis chamber from the analytical stream. In this approach label incorporation from the starting materials can be observed in both volatile and nonoxidative conditions for mechanistic studies. In addition, monitoring of redox potentials, oxygen consumption, and color generation of relevant model systems over time were also carried out at different temperatures. The data collected have indicated that perturbation in the redox potential of Maillard model systems by external (oxidizing conditions) or internal (formation of reductones) factors can alter the balance among the four critically important groups of precursors: alpha-dicarbonyl, alpha-hydroxycarbonyl, 2-aminocarbonyls, and 2-(amino acid)-carbonyl compounds and hence control the relative importance of aromagenic versus chromogenic pathways.

Acquired but reversible loss of erythrocyte complement receptor 1 (CR1, CD35) and its longitudinal alteration in patients with severe acute respiratory syndrome

This longitudinal study investigates the change of erythrocyte complement receptor (E-CR1) expression in patients with severe acute respiratory syndrome (SARS). Circulating E-CR1 expression was semiquantified by flow cytometric analyses in 54 SARS patients and in 212 healthy individuals as a control. Since E-CR1 expression is influenced by the genetic polymorphisms in the CR1 gene, a major genetic polymorphism located within intron 27 of the CR1 gene was simultaneously analysed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The results showed that the expression level of E-CR1 (referred to as net fluorescence intensity values, NFI) was statistically correlated with the relevant genetic genotypes among the Chinese population including the healthy individuals (NFI: 5·14 ± 0·82, 3·57 ± 0·66 and 2·67 ± 0·32 for HH, HL and LL genotypes, respectively) and SARS patients (NFI: 3·52 ± 0·91 and 2·63 ± 0·70 for HH and HL genotypes, respectively). Interestingly, the expression density of E-CR1 was found to fall significantly during the initiation and progressive phases (weeks 1 and 2 after the disease onset) and gradually returned close to normal through their whole convalescent phase (beginning from weeks 2 or 3 to weeks 7 or 8) in SARS patients irrespective CR1 genotype. In conclusion, our findings, at least, suggest that E-CR1 is likely involved in immune pathogenesis of SARS disease.

Lipid class and fatty acid composition of the protozoan parasite of oysters, Perkinsus marinus cultivated in two different media

The meront stage of the oyster protozoan parasite, Perkinsus marinus, cultivated in two media with different fatty acid profiles was analyzed for its fatty acid and lipid class composition. The composition of fatty acids in the prezoosporangium stage of the parasite as well as that of the host oyster were investigated. Although the lipid class composition of meronts was dominated by phospholipids and triacylglycerol, there was no triaclgycerol detected in either culture medium. Despite the difference in fatty acid composition of the two media, the fatty acid composition of meronts in each medium was dominated by 14:0, 16:0, 18:0, 18:1(n-9), 20: (n-9), 18:2(n-6) and 20:4(n-6), a profile that differed from its host. The quantities of total lipids and fatty acids in meronts increased as the number of meronts increased and far exceeded the initial amounts in the media and in the initial cell inoculum. The meronts harvested 25 d post-inoculation, had about 3 to 6 times higher total lipids and 4 to 13 times higher fatty acids than the amounts contained in the media. The fatty acid profiles of both prezoosporangia and oysters resembled each other and consisted primarily of 16:0, 20:4(n-6), 20:5(n-3), 22:2delta7,15, and 22:6(n-3). These results indicate that during meront proliferation, the parasite synthesizes certain fatty acids and lipid classes. For development from meront to prezoosporangium, the parasite may rely on its host for lipid resources.

Lipid class composition of the protozoan Perkinsus marinus, an oyster parasite, and its metabolism of a fluorescent phosphatidylcholine analog

Perkinsus marinus is one of two important protozoan parasites of the eastern oyster, Crassostrea virginica. The other is Haplosporidium nelsoni. Lipids extracted from 7-d-old in vitro cultured P. marinus meronts, incubated with fluorescent-labeled phosphatidylcholine (FL PC) and nonincubated P. marinus meronts, were analyzed by a high-performance liquid chromatography (HPLC) system equipped with a diol phase column, in combination with thin-layer chromatography coupled with a flame-ionization detector (TLC/FID), and high-performance thin-layer chromatography (HPTLC). Various polar and neutral lipid classes were separated by HPLC using a two-gradient solvent system. Five polar lipid classes--phosphatidylcholine (PC), phosphatidylethanolamine (PE), cardiolipin (CL), sphingomyelin (SM), and phosphatidylserine (PS)--were identified from P. marinus extracts. Four neutral lipid classes--triacylglycerol (TAG), steryl ester (SE), cholesterol (CHO), and fatty alcohol--were distinguished. TLC/FID analysis of meront lipids showed that the weight percentages of PC, PE, CL, SM, PS/PI, TAG, SE, and CHO were 21, 10.7, 4, 2.3, 4.3, 48.7, 7.8, and 1.2%, respectively. HPLC and HPTLC analyses revealed the presence of two SM and PS isomers in P. marinus extracts. Perkinsus marinus effectively incorporated FL PC acquired from the medium and metabolized it to various components (i.e., free fatty acid, monoacylglycerol, diacylglycerol, TAG, PE, and CL). Uptake and interconversion of FL PC in P. marinus meronts increased with time. After 48 h the total uptake of fluorescence (FL) was 28.9% of the FL PC added to the medium, and 43% of the incorporated FL resided in TAG.

Effects of PCBs sorbed to algal paste and sediments on the stress protein response (HSP70 family) in the eastern oyster, Crassostrea virginica

This study examined the stress protein response (HSP70 family) of reproductively inactive oysters fed 0.7 g algal paste containing 0, 0.35 and 3.5 micrograms polychlorinated biphenyls (PCBs) daily. A second set of treatment groups investigated the combined effect of PCBs and sediments (0.3 g sediments daily per oyster) on HSP70 response. After 8 weeks of PCB exposure, oyster tissues (mantle and gill) were sampled and analyzed for HSP70. Preliminary results did not show a significant effect in HSP70 response in oysters fed PCB sorbed to algal paste, albeit PCBs accumulated up to 1342 ng/g dry weight in the mantle, and up to 180 ng/g dry weight in gill tissues. However, the addition of sediments caused a significant increase in HSP70 levels of gills and mantle, although the mantle was less sensitive to the sediments.

The effect of PCBs on glycogen reserves in the eastern oyster Crassostrea virginica

Recent declines in Chesapeake Bay oyster populations have been attributed to disease, and reduced water quality from pollution. The stress associated with pollutant exposure may reduce energy available for growth and reproduction. Polychlorinated biphenyls (PCBs) are lipophilic contaminants that may potentially affect mobilization of lipid reserves, increasing reliance on glycogen stores, which could otherwise be utilized to supply energy for gametogenesis. Thus, PCBs may indirectly affect glycogen stores in oysters in a deleterious manner. To test for this effect, reproductively inactive oysters were exposed to PCBs by feeding individuals 0.7 g of algal paste containing 0, 0.35, or 3.5 micrograms PCBs daily for 8 weeks. Additionally, a group of oysters was exposed to PCBs (0, 0.35, and 3.5 micrograms) plus 0.3 g of non-toxic artificial sediment to examine interactive effects of sediment particles and PCBs. Adductor muscle, mantle, and gonadal tissues were analyzed for glycogen content. Results suggest that glycogen content is reduced in the adductor muscle with increasing PCB exposure, but there are no effects of PCBs in the mantle and gonadal tissues.

PCB uptake and accumulation by oysters (Crassostrea virginica) exposed via a contaminated algal diet

Reproductively active oysters were fed daily with 0.2 g algal paste containing 0, 0.1, and 1.0 microgram polychlorinated biphenyls (PCBs) (1:1:1 mixture of Aroclor 1242, 1254 and 1260) for either 15 or 30 days, and accumulation of PCBs in different organ tissues and eggs assessed. The effects of PCB exposure on lipid content, lipid class and fatty acid composition were also evaluated. PCBs were accumulated by the oysters and transferred to the eggs. PCB accumulation in oysters was dose, time and tissue dependent. Mean PCB contents were 3150, 1970, and 250 ng/g dry wt., respectively, in the visceral mass, gills + mantle and muscle of oysters fed algal paste containing 1.0 microgram PCBs for 30 days. The PCBs in the eggs from the same oysters reached 671 ng PCBs/g dry wt. Feeding oysters with PCB-sorbed algal paste for 30 days significantly increased phospholipid and free fatty acid contents in gills + mantle tissue compared to the same tissues in the undosed control.

Acoustic waves and the real-time study of biochemical macromolecules at the liquid/solid interface

The adsorption of the proteins, bovine serum albumin, fibrinogen, avidin and neutravidin (non-glycosylated form of avidin) to a variety of surfaces imposed on thickness shear mode sensors in examined in a flow-injection analysis format. In all cases, adsorption of these moieties was essentially irreversible, although the magnitude of adsorption was dependent on surface free energy and functional group chemistry. Also described is the direct, real-time detection of the binding of peptides to HIV-1 TAR RNA bound on a thickness-shear mode (TSM) sensor surface. The results clearly indicate that responses are discriminatory for two different peptides. In order to provide a theoretical backcloth for the experimental measurements, a new model for the operation of the TSM in liquids is presented.

Acid phosphatase activity in Perkinsus marinus, the protistan parasite of the American oyster, Crassostrea virginica

The effect of temperature (4, 12, 20, and 28 C) and osmolality (400, 570, and 840 mOsm/kg) on extracellular acid phosphatase (AP) secretion in vitro, and ultrastructural localization of AP activity in the parasite were investigated. The extracellular AP secretion by Perkinsus marinus was cell density dependent (P < 0.001). Increasing culture temperatures resulted in increased P. marinus proliferation concomitant with AP secretion (P < 0.0001). AP secretion was similar in P. marinus cultured at 400 and 570 mOsm/kg media, but higher than P. marinus cultured at 870 mOsm/kg media. Results of the ultrastructural study revealed that intense AP activity was in the nucleus of the parasite. Based on its distribution in the nucleus, AP may be playing a role in events leading to cell cycle regulation.

In vitro interaction of Perkinsus marinus merozoites with eastern and Pacific oyster hemocytes

This study compared hemocyte responses of eastern and Pacific oysters to Perkinsus marinus, in vitro. Except for the percentage of hemocytes associated with P. marinus there was little or no significant difference between eastern and Pacific oysters with regard to their hemocytic response to P. marinus. In phagocytosis assays, merozoites were bound to all hemocyte types but in unequal proportions, unlike zymosan which was found predominantly associated with granulocytes. The number of merozoites enlarging in Ray's fluid thioglycollate medium after incubation with hemocytes in plasma for one day was significantly lower than after incubation in plasma alone in both oyster species. Electron microscopy or merozoites indicated that the parasites were rapidly phagocytosed and that some of the merozoites showed signs of degeneration in less than 12 h. The results suggest that limited intracellular killing of P. marinus had occurred, but was probably not mediated by oxygen metabolites, since no increase in chemiluminescence was observed when hemocytes of either eastern or Pacific oysters were exposed to merozoites.

Suppression of chemiluminescence of eastern oyster (Crassostrea virginica) hemocytes by the protozoan parasite Perkinsus marinus

Experiments were conducted to determine the ability of the protistan parasite, Perkinsus marinus, to inhibit chemiluminescence of hemocytes from the eastern oyster, Crassostrea virginica. Luminol-enhanced chemiluminescence (CL) was used to measure the production of reactive oxygen intermediates (ROI) generated by oyster hemocytes using zymosan as a stimulant. To determine whether P. marinus suppresses ROI evoked from zymosan-stimulated hemocytes, live or heat killed P. marinus in filtered estuarine water (YRW) (salinity = 20 ppt) were added to (1) zymosan-stimulated hemocytes after CL reached its peak, or (2) hemocytes at the same time as zymosan, and reduction of CL responses were recorded. In both tests, controls received only estuarine water. Live P. marinus meronts significantly suppressed ROI production by zymosan-stimulated hemocytes. The suppression of ROI production was dose dependent. Suppression of ROI production from zymosan-stimulated hemocytes by heat killed P. marinus was significantly less than by live P. marinus. Similarly, CL of hemocytes was reduced, though not significantly when hemocytes were exposed to YRW preincubated with P. marinus. When P. marinus meronts were used as a stimulant, no CL response was elicited. Results of this study suggest that P. marinus cells are able to suppress ROI release from oyster hemocytes, thus evading this component of the host's defense.

The latencies of sympathetic skin responses

The sympathetic skin response (SSR) was measured in 35 normal healthy adults and in 40 patients with diabetic polyneuropathy. When recording from the hand or the foot, the SSR latency was the same whether stimulating at the hand or the foot. This may suggest that the conduction velocity of afferent fibers is much faster than that of efferent fibers, so that the former do not contribute to the SSR latency. The SSR amplitudes were significantly reduced in diabetic patients (p < 0.001), but their latencies were normal as long as responses could be detected. It is possible that some surviving unmyelinated fibers and/or regenerated fibers take the responsibility for normal conduction. Another possible explanation is that the postganglionic unmyelinated fibers in polyneuropathy may represent themselves as 'all or none', i.e., either the fibers conduct with normal velocity or they do not conduct at all.

Incidence of stroke in Taiwan

BACKGROUND AND PURPOSE

Few epidemiological studies concerning the incidence of stroke have been conducted in Taiwan. In an attempt to investigate this common disease, we studied the incidence of stroke in Taiwan in a prospective incidence study.

METHODS

A cohort of 8,562 stroke-free people were followed up for 4 years to observe new stroke occurrence. The methods of sampling the study population have been reported elsewhere. In addition to the help of local doctors, who reported the new stroke cases, we also sent public nurses to visit the study population annually to screen the new cases of stroke.

RESULTS

There were 104 (61 men and 43 women) first-ever stroke cases identified by a neurologist in a period between October 1, 1986 and December 31, 1990. The average annual incidence rate of first-ever stroke for people aged 36 years or older in this study was 330 per 100,000. Incidence rate was higher in eastern Taiwan and in rural communities. Percentages of the major types of stroke were as follows: cerebral infarction, 71%; cerebral hemorrhage, 22%; subarachnoid hemorrhage, 1%; and unclassified, 6%. The significant risk factors for stroke were hypertension and intake of food with a high sodium content.

CONCLUSIONS

The age-specific incidence rates in this study are higher than those reported from the United Kingdom and the United States. The rates are close to those in a report from Japan and a report from a city in mainland China at the same latitude. Cerebral hemorrhages are more common among people in Taiwan than among Occidental people.

Effects of palm carotenoids in rat hepatic cytochrome P450-mediated benzo(a)pyrene metabolism

Using benzo(a)pyrene (BaP) metabolism as a probe for chemical carcinogenesis, in vitro and in vivo effects of palm-oil carotenoid [beta-carotene (BC), alpha-carotene (AC), or canthaxanthin (CTX)] on BaP metabolism in the rat hepatic cytochrome P450-mediated monooxygenase system were studied. Apparent Michaelis-Menten constants (Km) for formation of the precursor carcinogen, 7,8-dihydrodiol BaP, were found to be 14.4 (BC), 1.74 (AC), and 0.7 (CTX) mumol/L. The order of anticarcinogenic strength established in this study was BC much greater than AC greater than CTX. Increased formation of the detoxification intermediate, 3-hydroxy BaP, with increased carotenoid concentration was observed. The order of detoxification strength was BC greater than AC = CTX. The presence of carotenoids in vivo inhibited BaP metabolism. Using 9,10-dihydrodiol BaP as an indicator for inhibition, the order of the antioxidative activity was palm oil (with carotenoids) greater than BC greater than CTX greater than palm oil (without carotenoids). BC and AC may selectively modify the rat-liver microsomal enzymes, thus providing a biochemical mechanism for the inhibitory effect of palm carotenoids on chemical carcinogenesis.

Common carotid artery dissection diagnosed by ultrasonic image: report of a case

Carotid artery dissection is not uncommon and usually starts at the internal carotid artery. It rarely begins in the common carotid artery. It may cause symptoms of cerebral vascular insufficiency such as stroke and transient ischemic attacks. The case reported here is a 38-year-old man with an acute onset of left hemiparesis 2 hours after drinking three bottles of beer. Computed tomographic scan showed cerebral infarction in the territory of the right middle and anterior cerebral arteries. Ultrasonic imagings showed an intimal flap, starting at the bifurcation of the right common carotid artery, indicative of arterial dissection. Angiography confirmed the diagnosis and the arterial dissection appeared to extend into and terminate at the internal carotid artery.

Proximal slowing of nerve conduction velocity in carpal tunnel syndrome

Slowing of median nerve conduction velocity (NCV) over the forearm segment is often seen in patients with carpal tunnel syndrome (CTS). In order to evaluate the extent and significance of this retrograde slowing of NCV, we examined 132 CTS hands from 84 patients diagnosed by both clinical and electrophysiological findings and both hands of 50 normal subjects. The mean median motor NCV was relatively slow in the CTS group (55.8 +/- 4.4 m/s) as compared with normal subjects (60.0 +/- 3.4 m/s, p less than 0.001). Mean median motor NCV was slower in CTS with low median motor amplitudes (less than 6.0 mV), 50.9 +/- 5.7 vs 56.1 +/- 4.1 m/s, p less than 0.001; and absent median sensory responses, 51.8 +/- 5.3 vs 56.0 +/- 4.3 m/s, p less than 0.001. There were 14 CTS hands with abnormally slowed median motor NCV (less than 50 m/s). This group had significantly lower median sensory and motor amplitudes, and longer motor distal latencies and sensory wrist-palm conduction time as compared with CTS hands with normal median motor NCV (greater than 50 m/s), p less than 0.001 for each parameter. These findings indicate that the proximal median motor NCV is usually affected by the distal lesion of CTS. Furthermore, the motor nerve conduction velocity proximal to the wrist is reduced in proportion to the severity of the nerve lesion. Electromyographers should be aware of this phenomenon and avoid the error of lesion localization.

Prevalence of stroke in Taiwan

We investigated the prevalence of stroke in Taiwan in an epidemiologic study of stroke, diabetes, and cardiovascular disease that used a two-phase survey design. The study population was drawn by cluster sampling and consisted of both urban and rural communities from four regions of Taiwan. There were 8,705 people 36 years of age or older interviewed during the period of October 1 to December 31, 1986, and 143 cases of completed stroke were later identified by a neurologist. The point prevalence rate for people aged 36 or older in our study was 1,642/100,000 population (95% confidence interval 1,389-1,942/100,000). Prevalence rates differed significantly among the four study regions and between urban and rural communities; prevalence was greater in northern Taiwan and in urban communities. Percentages of the major types of stroke in 143 stroke survivors were as follows: cerebral infarction 67.1% (96 cases), cerebral hemorrhage 14.0% (20 cases), subarachnoid hemorrhage 4.2% (six cases), and unclassified 14.7% (21 cases). Of the stroke survivors, 67.1% were independent in activities of daily living, and 75.5% were independent in ambulation. Hypertension, heart disease, diabetes mellitus, and a family history of stroke were significantly more common in stroke survivors than in strokefree individuals.

Ocular bruits in ischemic cerebrovascular disease

A total of 72 ocular bruits in 50 patients with symptoms of atherothrombotic ischemic cerebrovascular disease were studied with continuous-wave Doppler ultrasonography with spectrum analysis (Dopscan). Fourteen patients also had conventional angiography, and 14 had digital subtraction angiography. Ocular bruits by augmentation flow due to occlusion (seven bruits, 9.7%) or tight stenosis (17 bruits, 23.6%) of the contralateral internal carotid artery accounted for only 24 ocular bruits (33.3%). In contrast, siphon stenosis ipsilateral to the ocular bruit was a very common finding. All 14 patients studied with conventional angiography had variable degrees of siphon stenosis ipsilateral to the ocular bruits; there was one angiography failure. We conclude that siphon stenosis can cause ocular bruit alone or can act in combination with augmentation flow by contralateral carotid occlusion or tight stenosis. The difference in their relative occurrence in our patients compared with previous reports probably reflects racial differences in the distribution of stenotic or occluded lesions of the carotid artery between our patients and Caucasian patients. The ocular bruit was the only auscultatory finding in more than a quarter of our patients (14 of 50, 28%).

Spinal cord proliferative sparganosis in Taiwan: a case report

A 43-year-old woman suffered from low back pain and bilateral footdrop. A cisternal myelogram unexpected revealed multiple filing defects in the spinal canal extending from the lower cervical region to the caudal equina. Diagnostic exploration revealed numerous cystic organisms adhering to the spinal cord and nerve roots. Histopathological examination showed these organisms to be proliferative sparganum cestode larvae. Although these cestode larval infections have been reported a dozen times in humans from various parts of the world, this is probably the first reported case of spinal cord infection.

Non-obstructive idiopathic pachymeningitis cervicalis hypertrophica

Two young men had similar nonobstructive idiopathic pachymeningitis cervicalis hypertrophica, causing chronic (13 and 11 years respectively) C8-T1 radiculomyelopathy proved by surgical and pathological findings. The preoperative Queckenstedt tests and myelography showed no evidence of CSF obstruction. These unusual findings contrast with previous reports which all described complete or at least partial, block. The findings on metrizamide computed tomogram have not been described before. In the two patients it revealed diffuse cord atrophy from C7 to T2 and hemiatrophy with lateral beaking from C4 to C7. The patients benefited from multiple transverse durotomies. The main pathogenesis of the cord atrophy was the compromizing of feeding radicular arteries rather than direct compression.

Brain SPECT imaging with 99Tcm-hexamethylpropyleneamine oxime in the early detection of cerebral infarction: comparison with transmission computed tomography

A new cerebral blood flow agent, 99Tcm-hexamethylpropyleneamine oxime (HM-PAO), was evaluated for early detection of acute cerebral infarction in conjunction with the transmission computed tomographic (CT) studies. The data from 22 cases were analysed. Results reveal that 99Tcm-HM-PAO enables the early detection of acute cerebral infarction prior to CT with rather proper depiction of the extent of physiological abnormality in the majority of patients. This promising result together with the lack of logistical problems will make 99Tcm-HM-PAO a useful and practical agent worldwide for diagnosing and managing acute cerebral infarction.

Trends in mortality from cerebrovascular disease in Taiwan

The rate of decline in the age-adjusted death rate from cerebrovascular disease (CVD) in Taiwan is not as rapid as in the United States and Japan, and the trends of CVD mortalities have not decreased steadily during the period 1972-1983. A low record of hypertension regulation (5.0%-12.7%), a high proportion (47.1%) of stroke due to cerebral hemorrhage (by clinical assessment), and a high fatality rate (40.1%) for cerebral hemorrhage may account partially for the slower declining rate. A geographic difference in the downward trend of CVD death rate was observed in this period. Districts remote from the major cities have had the lowest decline in CVD death rate.

A clinical and electrophysiological study of patients with polychlorinated biphenyl poisoning

Neurological examination of 28 patients, 4 years after serious poisoning by polychlorinated biphenyl contaminated cooking oil, are compared with similar examinations of the same patients two years earlier (in 1980). Clinical peripheral sensory neuropathy was found in 54%, headache in 36% and dizziness in 46% of the patients; these findings did not differ (p greater than 0.1) from those in 1980. Although the mean blood polychlorinated biphenyl concentration (19.2 ppb) in the patients was lower (p less than 0.001) than that in 1980 (35.9 ppb), it was still higher than the normal value (less than 4 ppb). There was no difference in the blood polychlorinated biphenyl concentration of patients with neurological manifestation from those without. Although the mean motor and sensory nerve conduction velocities (MNCV and SNCV) were still slower (p less than 0.06) than the mean normal NCV, the mean MNCV of tibial nerve and SNCV of sural nerve were improved (p less than 0.06) as compared with those in 1980. EEGs were normal except in two cases showing nonspecific slow wave changes. In addition, evoked potentials (somatosensory, visual and brain-stem auditory) were measured in this study and found to be normal in all 12 cases examined.

The effect of xanthine derivatives on red blood cells: microelectrophoretic studies

The effect of xanthine derivatives on the variation of surface charges of red blood cells has been investigated. Results of mobility curves showed that the derivatives increase the surface charges on the cells, whereas there is little effect on the surface charges of liposomes.