Striatal tyrosine hydroxylase-positive neurons are associated with L-DOPA-induced dyskinesia in hemiparkinsonian mice

L-3,4-Dihydroxyphenylalanine (L-DOPA) is the therapeutic gold standard in Parkinson's disease. However, long-term treatment is complicated by the induction of debilitating abnormal involuntary movements termed L-DOPA-induced dyskinesias (LIDs). Until today the underlying mechanisms of LID pathogenesis are not fully understood. The aim of this study was to reveal new factors, which may be involved in the induction of LID. We have focused on the expression of striatal tyrosine hydroxylase-positive (TH+) neurons, which are capable of producing either L-DOPA or dopamine (DA) in target areas of ventral midbrain DAergic neurons. To address this issue, a daily L-DOPA dose was administered over the course of 15 days to mice with unilateral 6-hydroxydopamine-induced lesions of the medial forebrain bundle and LIDs were evaluated. Remarkably, the number of striatal TH+ neurons strongly correlated with both induction and severity of LID as well as ΔFosB expression as an established molecular marker for LID. Furthermore, dyskinetic mice showed a marked augmentation of serotonergic fiber innervation in the striatum, enabling the decarboxylation of L-DOPA to DA. Axial, limb and orolingual dyskinesias were predominantly associated with TH+ neurons in the lateral striatum, whereas medially located TH+ neurons triggered locomotive rotations. In contrast, identified accumbal and cortical TH+ cells did not contribute to the generation of LID. Thus, striatal TH+ cells and serotonergic terminals may cooperatively synthesize DA and subsequently contribute to supraphysiological synaptic DA concentrations, an accepted cause in LID pathogenesis.

Cell adhesion molecule expression in human lens epithelial cells after corticosteroid exposure

Aim:

The aim of the study was to investigate changes in cell adhesion molecule expression in human lens epithelial cells (HLEC) subjected to glucocorticoids.

Methods:

Human lens epithelial cells were exposed to different concentrations of dexamethasone for 24 hours. Cell adhesion molecule expression was studied by western blot and immunohistochemistry of vimentin, N-cadherin, E-cadherin, α-catenin, β-catenin and γ-catenin. Expression of the glucocorticoid receptor (GR) was also studied. Cell morphology was examined by transmission electron microscopy (TEM).

Result:

Expression of N-cadherin, α-catenin, β-catenin and GR was significantly decreased in dexamethasone exposed cells as compared to unexposed cells. No significant change in γ-catenin was present. Visualization of adhesion molecules, N-cadherin and α-catenin, by immunohistochemistry showed decreased antigen reactivity in dexamethasone exposed as compared to the unexposed cells. However, no change was seen for β-catenin and γ-catenin. E-cadherin was not detectable using western blot or immunohistochemistry.

TEM showed multilayering of cells, vacuole formation and appearance of electron-dense multivesicular bodies in HLEC exposed to 0, 0.1, 1, 10 and 100 αM dexamethasone.

Conclusion:

Glucocorticoids affect several adhesion molecules in lens epithelial cells, something that may contribute to the pathogenesis of posterior subcapsular opacification.

Evaluation of Factors Affecting Diffusion in Compacted Bentonite

The information available from the open literature and our studies on exclusion, sorption and diffusion mechanisms of ionic and neutral species in bentonite has been compiled and re-examined in relation to the microstructure of bentonite. The emphasis is placed on a more thorough understanding of the diffusion processes taking place in compacted bentonite. Despite the scarcity of experiments performed with neutral diffusants, these imply that virtually all the pores in compacted bentonite are accessible to neutral species. Anion exclusion, induced by the overlap of electrical double layers, may render the accessible porosity for anions considerably less than the porosity obtained from the water content of the clay. On the basis of the compiled data, it is highly probable that surface diffusion plays a significant role in the transport of cations in bentonite clays. Moreover, easily soluble compounds in bentonite can affect the ionic strength of porewater and, consequently, exclusion, equilibrium between cations, and surface diffusion.

Experimental Study of the Nickel Solubility in Groundwater and Cement Water Under Anoxic Conditions

The solubility of nickel under anoxic conditions was investigated in groundwater and in cement-conditioned water. The solubility was studied at 30 °C using the over-saturation method. The nickel concentrations were determined using 63Ni and liquid scintillation counting. The results indicate a nickel solubility of 1–10−4 mol/L in the cement water. The same solubility was also seen in groundwaters that had a pH of 9 or higher. No solubility limit was determined for groundwaters with pH values in the range of 7 to 9.

Coprecipitation of Ni With Calcite: An Experimental Study

At the Finnish candidate sites for a nuclear waste repository calcite (CaCO3) is a common fracture mineral, that may participate in coprecipitation processes. The objective of this work was to study the coprecipitation of the trace element Ni with CaCO3 under controlled conditions. The experiments were carried out at 30 °C in vessels closed to the atmosphere. Calcite-saturated 0.05 M NaCI solutions containing trace amounts of Ni2+ were contacted with calcite for periods of up to 42 days. The experimental data indicate that Ni coprecipitates with calcite as a result of recrystallization. The amounts of coprecipitated Ni and recrystallized calcite were determined using liquid scintillation counting and the isotopes 63Ni and 45Ca. The results are supported by a complementary SEM/EDS analysis of the solid phase.

Effects of dexamethasone on human lens epithelial cells in culture

PURPOSE

Treatment with glucocorticoids is a well known risk factor for cataract development, although the pathogenic mechanism has not been elucidated. The aim of the study was to investigate the effects of glucocorticoids in cultured human lens epithelial cells.

METHODS

Human lens epithelial cells (HLECs) were exposed to dexamethasone for 24 h. The number of viable cells was determined using the 3-[4, 5-dimethylthiazolyl-2]-2, 5-diphenyltetrazolium bromide (MTT) assay, and proliferation was quantified using Ki-67. Apoptosis was investigated by measuring caspase-3 activity and by evaluating nuclear morphology of cells stained with Hoechst 33342. Mitochondria depolarization was measured using the potential-sensitive color, JC-1. Cells were assayed for changes in superoxide production using dihydroethidium (HET), for alterations in peroxide production using dichlorofluorescein diacetate (DCFH-DA), and for glutathione (GSH) variations using monochlorobimane (MCB). Caspase-3 activity was also measured in HLECs simultaneously exposed to dexamethasone and the glucocorticoid antagonist, RU486.

RESULTS

Low doses of dexamethasone (0.1 microM) resulted in increased proliferation of HLECs. Apoptosis was increased in HLECs exposed to 1 microM, 10 microM, and 100 microM of dexamethasone as revealed by nuclear morphology studies. Apoptosis was also confirmed by measuring caspase-3 activation. No effect on superoxide production by dexamethasone was seen. There were no effects on GSH levels or mitochondrial depolarization either. Only the highest concentration of dexamethasone (100 microM) caused an increase in peroxide production. In HLECs incubated with the glucocorticoid antagonist, RU486, apoptosis was induced at a lower concentration of dexamethasone (0.1 microM) than with dexamethasone alone.

CONCLUSIONS

Low doses of dexamethasone cause a moderate increase in proliferation of cultured HLECs. Slightly higher but still physiologically relevant concentrations of dexamethasone result in a dose-dependent increase in apoptosis. Dexamethasone-induced apoptosis in HLECs does not seem to involve oxidative mechanisms. The proapoptotic effect of dexamethasone does not appear to act through the glucocorticoid receptor. Effects on proliferation and/or dysregulation of apoptosis in lens epithelial cells may be an important factor in human steroid-induced posterior subcapsular cataract.

The proteasome and intracellular redox status: implications for apoptotic regulation in lens epithelial cells

PURPOSE

This study aimed to investigate redox regulation of the proteasome as well as the effect of proteasome inhibition on intracellular oxidative status and apoptosis.

METHODS

Oxidative stress was induced in cultured human lens epithelial cells (HLECs) and intact mouse lenses by 100 microM H2O2. HLECs were also exposed to the reduced and the oxidized forms of glutathione (GSH/GSSG) and the reducing agent dithiotreitol (DTT). The chymotrypsin-like, the trypsin-like, and the peptidylglutamyl peptidase activities of the proteasome were measured using synthetic fluorogenic substrates. Superoxide as well as peroxide production, mitochondrial membrane potential, and the level of GSH was measured in HLECs after proteasome inhibition by MG-132 or lactacystin. Apoptosis was determined by measuring caspase-3 activation and by studying apoptotic nuclei after staining with Hoechst 33342.

RESULTS

All three peptidase activities of the proteasome were inhibited by 100 microM H2O2 and by the oxidized form of glutathione (GSSG), whereas the reduced form (GSH) stimulated chymotrypsin-like and peptidylglutamyl peptidase activities in HLECs lysates. Intact mouse lenses exposed to 100 microM H2O2 exhibited loss of transparency and trends of decreased chymotrypsin-like proteasome activity as well as decreased GSH levels. Inhibition of the proteasome in cultured HLECs caused significant increase in apoptosis and disturbed intracellular redox balance. Simultaneous addition of exogenous GSH completely abolished the increased apoptosis seen after MG-132 treatment.

CONCLUSIONS

This study supports the hypothesis that intracellular proteolytic and oxidative regulatory systems are tightly coupled. The current data also indicate that apoptosis by proteasome inhibition is mediated through oxidative mechanisms.

Possible model of an antiferroelectric twist grain boundary phase

Using x-ray and optical methods we have probed the structural organization of an antiferroelectric twist grain boundary phase (TGBC(a)) lying between the regular antiferroelectric smectic-C (SmC(a)* and the smectic-Q (SmQ) or isotropic phase. We find that the twist axis is everywhere perpendicular to the local smectic layer normal and that the helical superstructure is incommensurate with the smectic layer structure. The twist grain boundaries consist of a periodic lattice of alternating +1/2 and -1/2 dispirations, i.e., unit screw dislocations in combination with half unit disclinations. The molecular tilt plane is alternatingly parallel and perpendicular to the twist axis. We find that the optically measured tilt angle in the SmC(a)* phase is smaller than that measured by x rays, which is the opposite to what is found in the SmC* phase. This means that the core part tilts less than the end chains in the SmC(a)* phase, while it tilts more in the SmC* phase. On entering the TGB phase a clear decrease is measured in the tilt angle. This is explained by the elastic influence from the disclinations, which appear in this phase.

Irreducible memory function and slow dynamics in disordered systems

We show how the irreducible memory function can be obtained in a rather straightforward way, and that it can be expressed in terms of two contributions representing two parallel decay channels. This representation should be useful for treating systems with a slow time dependence and where eventually some internal degrees of freedom enters in the relaxation process, and cuts off an underlying ideal ergodic to nonergodic transition. We also show how the irreducible memory function under certain mild conditions defines a regenerative stochastic process, or a two level stochastic system. This leads to a picture with dynamical heterogeneities, where the statistical properties asymptotically are ruled by limit processes. This can explain the universal behavior observed in many glass-forming systems.

Pegylated interferon and ribavirin treatment for hepatitis C in haemodialysis patients

Standard therapy for chronic hepatitis C (HCV) is pegylated interferon in combination with ribavirin. There is limited experience with either drug in dialysis [end stage renal disease (ESRD)]. Six haemodialysis patients, four with HCV genotype 1, one with genotype 4 and one genotype 2 were treated with pegylated interferon-alfa-2b (n = 4) and pegylated interferon-alfa-2a (n = 2) for 24-48 weeks according to genotype with a dose of 50 or 135 mug/week respectively. All patients were given reduced ribavirin doses, initially 200-400 mg/day. Ribavirin trough plasma concentrations were measured with a HPLC method previously developed for earlier treatment studies, aiming at a target concentration of 10-15 micromol/L. Interferon related side-effects were common, in one patient peg-alfa-2b was permanently reduced to 50 mug every 9-10 days with improvement in tolerance. Average ribavirin dose was 170-300 mg/day. Ribavirin-induced anaemia was treated with high doses of erythropoietin and low doses of iron. Blood-transfusions were not needed. All patients became HCV-RNA-PCR negative during treatment which was completed or nearly completed in four patients. One patient terminated therapy prematurely due to pronounced interferon related side-effects and another died of myocardial infarction probably not related to therapy. Three patients have remained HCV-RNA negative with extended follow-up, two of whom have had a successful kidney transplant. Pegylated interferons are likely to become a valuable addition for HCV therapy in ESRD and are possible to combine with ribavirin. However the pharmacokinetics and tolerability of both peg-alfa-2a and 2b need to be studied more closely in prospective studies before definite dosing recommendations can be made.

Continuous exposure to glial cell line-derived neurotrophic factor to mature dopaminergic transplants impairs the graft’s ability to improve spontaneous motor behavior in parkinsonian rats

Functional recovery following intrastriatal transplantation of fetal dopaminergic neurons in animal models of Parkinson's disease is, at least in part, dependent on the number of surviving dopaminergic neurons and the degree of graft-derived dopaminergic reinnervation of the host striatum. In the present study, we analyzed whether continuous exposure of glial cell line-derived neurotrophic factor (GDNF) to mature dopaminergic grafts could further boost the functional outcome of widespread intrastriatal dopaminergic grafts. Rats with dopamine-denervating lesions received multiple intrastriatal transplants of fetal dopaminergic cells and graft-induced behavioral effects were analyzed in drug-induced and spontaneous motor behaviors. At three months after grafting, animals received intrastriatal injections of recombinant lentiviral vectors encoding for either human GDNF or the green fluorescent protein. Continuous exposure of GDNF to the grafts did not boost the functional recovery beyond what was observed in the control animals. Rather, in some of the spontaneous motor behaviors, animals in the GDNF-group showed deterioration as compared with control animals, and this negative effect of GDNF was associated with a down-regulation of the tyrosine hydroxylase enzyme. Based on these and our earlier results, we propose that intrastriatal administration of GDNF at the time of or shortly after grafting is highly effective in initially promoting the cell survival and fiber outgrowth from the grafts. However, once the grafts are mature, GDNF's ability to boost dopaminergic neurotransmission follows the same dynamics as for the native nigral dopaminergic neurons, which appears to be dependent on the concentration of GDNF. Since rather low doses of glial cell line-derived neurotrophic factor at nanogram levels appear to saturate these effects, it may be critical to adjust GDNF levels using tightly regulated gene expression systems.

Hepatitis C virus RNA kinetics during the initial 12 weeks treatment with pegylated interferon-alpha 2a and ribavirin according to virological response

To optimize treatment of chronic hepatitis C early identification of patients who will not achieve a sustained virological response (SVR) is desirable. We investigated hepatitis C virus (HCV) RNA kinetics at day 1 (in 15 patients; genotypes 1 and non-1, 9 and 6 respectively) at weeks 1, 4 and 12 (in 53 patients; genotypes 1 and non-1, 19 and 34, respectively) during treatment with pegylated interferon alpha-2a and ribavirin. Patients with SVR had a significantly more pronounced mean log10 decline from baseline in HCV RNA levels at weeks 1 and 4 compared with patients who failed to achieve SVR (1.99 vs 0.85 at week 1, P = 0.0003 and 2.89 vs 1.72 at week 4, P = 0.0159), whereas no difference was noted after day 1. For patients with a 2-log10 decrease in HCV RNA levels at day 7, the positive predictive value (PPV) for a SVR was 92%, whereas week 12 was the best time point for predicting a later nonresponse [negative predictive value (NPV) 92%] in patients failing to achieve a 2-log10 drop. For patients with genotype non-1 and a 2-log10 decrease in HCV RNA levels the PPV for a SVR was 89% week 1, and 79% weeks 4 and 12. The corresponding NPV for patients with genotype non-1 were 43, 40 and 100% respectively. During treatment with pegylated interferon alpha-2a plus ribavirin the HCV RNA decline at week 1 was an accurate predictor of SVR in patients who had achieved a 2-log10 drop in HCV RNA levels, whereas the lack of such decline week 12 was an accurate marker of a nonresponse.

Viral kinetics and treatment response in patients with hepatitis C during induction and standard interferon therapy in combination with ribavirin

BACKGROUND

The early decline of hepatitis C virus (HCV) RNA levels during therapy may predict the outcome and can be utilized to improve treatment regimens. We studied the HCV RNA levels during induction and standard interferon (IFN) and ribavirin treatment.

METHODS

Patients received IFN 3 MU daily for 14 days followed by 3 MU three times a week (induction group; n = 10), or IFN 3 MU three times a week from start (standard group; n = 21), in combination with ribavirin 1000-1200 mg/day. HCV RNA was quantified day 0, 1, 2, 3, 7, 14, 28, 56 and 84 during treatment, and tested qualitatively at the end of treatment and at follow-up.

RESULTS

The initial viral load decline was more pronounced in the induction group, and in patients infected with genotype non-1. The sustained response rate was not significantly different between the study groups. At day 1, the mean viral load decline from baseline was significantly greater in patients who became sustained responders than in those who became non-responders; 1.4 log (96%) versus 0.3 log (55%) (P < 0.05). All sustained responders had a viral load decline of at least 0.7 log (79%) after the first IFN dose.

CONCLUSIONS

Our short-term induction treatment did not improve the long-term treatment outcome significantly, although a trend was seen. An absent or low initial viral load decline can be used to predict non-response in the individual patient.

Hepatitis C virus kinetics during induction and standard 3 times a week interferon-alpha therapy

We studied HCV kinetics during the first 84 d of interferon-alpha (IFN) treatment. IFN was administered either at a dose of 3 million units daily for the first 14 d and thereafter 3 times per week (t.i.w.) (induction treatment), or at a dose of 3 million units t.i.w. throughout (standard treatment). No patient had received HCV treatment previously, and all had a pretreatment viral load of < 1.2 x 10(6) IU/ml at screening. Ten patients were given induction treatment and 21 received the standard t.i.w. regimen. Twenty patients were infected with genotype 1. At Day 2, the median HCV RNA level in the induction group was significantly lower compared to that of the standard treatment group. This significant difference persisted during the study period for patients infected with genotype 1, but was not maintained from Day 14 onwards for patients with genotype non-1. At Day 84, 80% (8/10) of patients in the induction group, compared to 16% (3/19) in the standard treatment group, had undetectable (< 600 IU/ml) HCV RNA levels (p < 0.05). We conclude that induction treatment resulted in a significantly greater decline in HCV RNA levels than standard treatment.

HCV RNA levels during therapy with amantadine in addition to interferon and ribavirin in chronic hepatitis C patients with previous nonresponse or response/relapse to interferon and ribavirin

Interferon (IFN) alpha in combination with ribavirin (RIB) is standard therapy for patients with chronic hepatitis C virus (HCV) infection. However, many patients do not respond with sustained HCV clearance to this therapy. At present, no accepted treatment strategy exists for these patients. Recent preliminary data have suggested that amantadine (AMA) is effective against HCV infection. In a pilot study, we treated 13 nonresponders and 10 response/ relapsers to previous IFN/RIB therapy with AMA 200 mg per day in combination with IFN 3 MU thrice weekly, and RIB 1000 mg per day for 24 weeks, with a 24-week follow-up period after end-of-treatment. At the end-of-treatment, 1 previous nonresponder and 5 previous response/relapsers were HCV RNA negative. At the end of follow-up, only 1 previous response/relapser remained HCV RNA negative and had a sustained response. During therapy, serum HCV RNA became undetectable in 4 previous nonresponders, of whom 3 had a breakthrough at week 24. Twenty-one patients continued therapy without dose reductions. One patient discontinued therapy prematurely due to sleeping disturbances, and another patient was withdrawn from therapy due to heavy alcohol intake. We conclude that the addition of AMA to IFN and RIB was well tolerated but had little, if any, impact on HCV RNA eradication in nonresponders or response/relapsers to previous IFN/RIB combination therapy.

Theoretical model for layer rotations in smectic-A* liquid crystals subject to asymmetric electric fields

Recently, observations of the rotation of smectic layers under certain experimental conditions have been reported in the literature. In this work, the mechanism of such rotations in chiral smectic-A* liquid crystals under the action of asymmetric, periodic electric fields is studied theoretically. The general conditions for layer rotations have been established using symmetry arguments, and a generalized dynamical theory of the chiral smectic-A* phase, coupling layer rotations and the electroclinic effect, has been developed. The theory is applied in the specific case when an asymmetric sawtooth electric field is applied over the system, and the dependence of the average angular velocity of the smectic layers on the relevant material constants of the liquid crystal and experimental control parameters is calculated. By rewriting the final equations into dimensionless form, it is demonstrated that the system exhibits a universal behavior, reducing the number of independent material constants and control parameters considerably.

The anti-HBs response after 2 different accelerated intradermal and intramuscular schemes for hepatitis B vaccination

To study early seroconversion rates after hepatitis B vaccination intramuscular (i.m.) and low-dose intradermal (i.d.) vaccination was compared when given either according to the registered 0, 4, 8 weeks scheme (scheme A), or to an accelerated 0, 2, 6 weeks scheme (scheme B). Medical staff received either 2 microg i.d. or 20 microg i.m. of a recombinant hepatitis B vaccine, in a non-randomized open trial. Two weeks after the third dose i.m. vaccinees overall had significantly higher rates of protective anti-HBs levels (anti-HBs > or = 10 IU/I), (23/30, 77%) compared with i.d. vaccinees (75/166, 45%) (p < 0.001). We conclude that when rapid protection against hepatitis B virus (HBV) infection is desirable, such as for post-exposure prophylaxis, an accelerated low-dose i.d. vaccination schedule cannot be used.

N-terminal proANF in acute atrial fibrillation: a biochemical marker of atrial pressures but not a predictor for conversion to sinus rhythm. Digitalis in Acute Atrial Fibrillation (DAAF) Trial group

BACKGROUND

Atrial filling pressures are increased in acute atrial fibrillation, which stimulates the release of atrial natriuretic factor pro-hormone, proANF.

METHODS

In a randomized trial comparing digoxin with placebo in 216 patients, we investigated whether the baseline plasma level of N-terminal proANF is a predictor for conversion to sinus rhythm and the relation among N-terminal proANF, conversion to sinus rhythm, and changes in heart rate.

RESULTS

N-terminal proANF was increased at baseline and decreased significantly in patients converting to sinus rhythm, whereas it was mainly unchanged in nonconverters. N-terminal proANF was not a predictor of conversion to sinus rhythm. A relation was found between relative changes in heart rate and N-terminal proANF in nonconverters.

CONCLUSION

The level of N-terminal proANF does not predict conversion to sinus rhythm, which indicates that hemodynamics per se is not important. There is a correlation between relative changes in heart rate and N-terminal proANF in nonconverters.

Interferon-alpha 2b treatment in hepatitis B carriers. Effect on hepatitis B virus DNA levels in children infected with different genotypes

Eleven hepatitis B virus (HBV) carrier children, infected with genotypes A-D, were treated with interferon-alpha. Two children had a sustained loss of hepatitis B e-antigen and HBV DNA. They were infected with the non-Asian genotypes A and D, and had low HBV DNA and high ALT levels in serum before treatment. However, HBV DNA titres decreased during treatment also in children infected with the East-Asian genotypes B and C.

Use of an enzyme thermistor for semi-continuous blood glucose measurements

A method to monitor glucose in whole blood is presented. The aim of the project was to develop a prototype for a bedside monitor system for semi-continuous monitoring of the blood glucose concentration, requiring only one calibration. This was made possible by using the special advantage of the thermal sensor technique in combination with the adjustment of flow. The glucose concentration was determined from the difference between the sensor response and an estimated background signal. Using standard addition technique, calibration factors for background and sensitivity were set and remained unchanged during the monitoring. The background signal was 45 +/- 8 mV (mean +/- S.D., n = 8) and the sensitivity was 28 +/- 1 mV/mmol (mean +/- S.D., n = 4). Recovery in whole blood was 90-98% (mean 94%, n = 12). With an injection interval of 3 min the precision with the sensor was < 3% over more than 100 blood samples. Response time was about 60 s. The calculated glucose values correlated, r = 0.98, with the values obtained with an YSI glucose analyser (Yellow Springs Instruments. Yellow Springs, OH, USA), over the range 2-20 mmol/l.

Homeopathic Resistant Malaria

Multiresistant Plasmodium falciparum malaria is a major threat to travelers to subSaharan Africa. However, even if chemoprophylaxis does not prevent clinical malaria in some individuals, it does lead to a reduction in the severity of the disease.1 In Sweden, we have recently seen five patients with malaria (three due to P. ovale and two due to P. falciparum) who have used homeopathic drugs for prophylaxis during visits to West Africa. We are concerned about this incidence and afraid that reduced confidence in modern medical malaria prophylaxis will encourage some individuals to try totally ineffective alternatives. Three women (57, 40, and 39 years old) visited Guinea Conacry in January 1995 as members of a group of 24 persons learning about African dances. The 57-year-old woman took mefloquine irregularly but vomited each time after intake. She also used Spenglersan M, which is a homeopathic drug that is administered (one drop daily in the bend of the arm) as malaria prophylaxis. The two other women used Spenglersan M only. They all fell ill with P. ovale malaria despite ongoing intake. Spenglersan M is said to contain both antigen from P. falciparum and antibodies against the parasite diluted to 1:1,000,000,000 concentration. The fourth case was a 26-year-old man who visited Ghana and Burkina Faso in October and November 1994. He used China D-6 for prophylaxis. This is a homeopathic preparation of the bark from the cinchona tree. Not even trace amounts of quinine were found in the tablets with a very sensitive high-performance liquid chromatographic method.2 Four days after returning from Africa he fell ill with P. falciparum malaria and received sulphadoxine-pyrimethamine treatment. After clinical relapse (RI), mefloquine was given and the patient was eventually cured. The fifth case was a 34-year-old woman admitted to hospital because of P. falciparum malaria after a visit to Guinea Conacry in January 1995. She had taken a homeopathic drug, Charaka comp 118, as prophylaxis. The drug is said to contain different extracts from herbs diluted 30 times. At first she refused to stay in hospital, but 2 days later she was readmitted and treated in the intensive care unit because of severe malaria with hypotonia and anemia. She had hyperparasitemia with 23% infected erythrocytes. Exchange transfusion was done, quinine was given, and the patient recovered without sequelae. The mortality is about 1% in people with P. falciparum infection.3 We therefore urge the readers to stand up against the dangerous use of homeopathic drugs and instead motivate travelers to use protective malaria prophylaxis.

Increased yield of homogeneous HIV-1 reverse transcriptase (p66/p51) using a slow purification approach

A chromatographic procedure to purify recombinant reverse transcriptase (RT) from human immunodeficiency virus-1 is reported. A bacterial system which expressed large amounts of p66 RT polypeptide was used. The purification scheme was optimized for high-yield production of homogeneous p66/p51 RT using a combination of chromatographic matrices in the following order: Q-Sepharose, heparin-Sepharose, phenyl-Sepharose, S-Sepharose, Poly(A)-Sepharose and Q-Sepharose. The p66 polypeptide remained intact after the first chromatographic step on Q-Sepharose, where it was recovered in the non-adsorbed fraction. A high yield of p66/p51 RT was obtained when the time from application to elution of heparin-Sepharose in the second chromatographic step was prolonged. Phenyl-Sepharose was used in the next chromatographic step to separate the heterodimeric forms of RT from p66 RT on the basis of hydrophobicity. The chromatography on S-Sepharose resolved the major heterodimeric form, p66/p51, from other heterodimeric variants. Further purification was done by affinity chromatography on Poly(A)-Sepharose followed by anion-exchange chromatography on Q-Sepharose. Amounts of 25-35 mg of the pure heterodimer p66/p51 RT were recovered from 50 g of bacterial cells.

Purification, characterization and crystallization of recombinant HIV-1 reverse transcriptase

The pol I gene from HIV-1 encoding the protease, reverse transcriptase (RT) and endonuclease has been expressed in Escherichia coli. By modifying the fermentation conditions and developing a new purification scheme, the yield of purified RT has been increased substantially compared with that obtained in an earlier procedure. The expressed RT was purified to homogeneity by ammonium sulphate fractionation followed by chromatography on DEAE Sepharose, Heparin Sepharose, S Sepharose and Poly(A)-Sepharose. The purified HIV-RT is a heterodimer (p66/p51) with an isoelectric point close to 8 and with a tendency to aggregate. The proteolytic product (p51), corresponding to the N-terminal end of the RT molecule, was isolated and identified, as were also some bacterial polypeptides that co-elute with HIV-RT during the early stages of the purification. The heterodimer was crystallized in several morphological forms using the vapour-diffusion hanging drop technique. To concentrate the protein and to change the buffer for crystallization, reverse-salt-gradient chromatography and micropreparative columns were used. The best crystals diffracted to 9 A resolution. The best crystals of native RT diffracted to 9 A resolution and in complex with nucleic acids to 4.5 A resolution (using a rotating anode X-ray source).

Absolute bioavailability of nicotine applied to different nasal regions

The absolute bioavailability of nicotine administered nasally, as drops to the nasal conchae and nasal septum, and as a nasal spray, has been studied in eight healthy volunteers. Single nasal doses of 1 mg nicotine were given and plasma concentrations of nicotine were followed for 6 h. Compared to an intravenous infusion of nicotine, the bioavailability of the nasal administrations was 60 to 75%. The rate of absorption was fast, the maximum concentration being reached after about 10 min. In the present study, there was no significant difference in the rate or extent of absorption between the different nasal treatments.

Holographic investigation of an industrial robot

Compliance of a revolute robot manipulator is studied experimentally by holographic interferometry using a pulsed ruby laser. In the analysis, loads simulating forces that the robot is subjected to in actual cases were applied to the robot in different robot configurations. Thereby, the elastic compliance and deformation patterns of each joint and link were obtained. Experiments were performed on the ASEA IRb/6. The great influence of load-induced effects on accuracy were verified. The results provide a sound basis for corrective measures intended to minimize these effects. Holographic interferometry provides an extremely reliable way of revealing the 3-D behavior of a robot under load.