Tolerability and Effectiveness of Malaria Chemoprophylaxis with Mefloquine or Chloroquine with or without Co-medication

Background: To determine the relevance of drug interactions with co-medication for effectiveness and tolerability of antimalarial chemoprophylaxis. Method: A database (MALPRO2) on travelers on their flight home from Africa to Europe between July 1988 and December 1991 was reanalyzed. It contains data on prophylaxis with mefloquine (n = 48,264), with chloroquine (6,752), with chloroquine plus proguanil (19,727), and with no prophylaxis (3,871). The comparison of rates of malaria incidence and adverse events (AEs) between users and nonusers of co-medication was expressed by relative risk (RR). Results: Fifty-three percent of travelers (63% of females, 43% of males) used co-medication in all prophylaxis groups, with an average of 1.35 additional drugs per person and about two AEs reported per person. With the exception of antidiarrheals plus mefloquine, malaria incidence with co-medication was lower (RR = 0.8) than without co-medication. In all regimens, the proportion of travelers reporting AEs was about 1.5-fold with co-medication (p<.01); that reporting severe AEs was twice as high as compared to with no co-medication. Mefloquine AE rates for various classes of co-medication were similar to that of chloroquine, with highest AE and severity rates with neuropsychiatric drugs (excluding antiepileptics, RR = 1.9 and 2.9), and lowest rates with cardiovasculars (RR = 1.1 and 1.0). Various co-medications were used with different frequencies in males and females, and the latter reported more AEs. Conclusion: These data suggest that co-medications commonly used by travelers have no significant clinical impact on safety and effectiveness of prophylaxis with mefloquine or chloroquine. Increased frequency and severity of AEs when using co-medication rather is explained by underlying illness.

[Melatonin--clinical perspectives in prevention and therapy]

Melatonin is a hormone produced by the pineal gland mainly during the night. Its primary function is to coordinate biological rhythms. It may be used for therapy of chronobiological disorders, such as occur in jet lag, shift work, blind persons or in specific forms of insomnia. Due to its anti-gonadotropic effect, melatonin in high doses has been used as a contraceptive. In-vitro and animal studies have demonstrated cancer inhibition, immun-stimulating and rejuvenating effects, but none of these claims have been confirmed in clinical studies. Melatonin used over a short period is not associated with significant side-effects, but the tolerability of long-term administration is unknown. As the products are not always of pharmaceutical quality, one should avoid uncontrolled use of melatonin.

Immunochemical localization of the phylogenetically oldest receptor tyrosine kinase: existence in the marine sponge Geodia cydonium

Until now molecular data, elucidating the basis of invertebrate immunity are lacking. Previously both the gene and different cDNAs, coding for the ancestor of metazoan receptor tyrosine kinases (RTK), have been isolated from the marine sponge Geodia cydonium. The sponge RTK shows high polymorphism in the coding as well as in the non-coding parts of the gene. To further elucidate if the sponge RTK might be a molecule involved in self/non-self recognition the intracellular portion of the sponge RTK was expressed in Escherichia coli. The 59 kDa recombinant protein was used to raise monoclonal antibodies (McAb). The McAb recognized three polypeptides of sizes 135, 68 and 26 kDa by Western blotting. The McAb recognized only the plasma membranes of sponge cells as analyzed by immunohisto- and cytochemical studies. Northern blotting analysis revealed that the expression of the RTK gene depends on environmental conditions and on seasonal variations. Based on the high degree of polymorphism and on the immunochemical data we suggest that the RTK in G. cydonium might be involved in sponge immunity.

[Injection treatment of non-radicular lumbalgia]

Low back pain is the most expensive condition in industrialized countries. Approximately 65-80% of the population will be afflicted with low back pain at some point during their life. Low back pain has many causes and can originate from any of several pain-sensitive foci, among which are facet joints, sacroiliac joint, muscle and ligaments. Primary care in the acute phase consists of nonsteroidal anti-inflammatory drugs to address the biochemical and inflammatory mediators of pain or skeletal muscle spasmolytics to reduce low back pain symptoms. Injection procedures should be reserved for the patients with low back pain who fail to respond to a directed, conservative treatment trial and have had pain for at least 2 weeks duration. Eliminating sensation from a certain pain source has been proposed as a way to allow an examiner to determine if that joint is responsible for the patient's pain. Injections of local anesthetic into the facet joint or around its nerve supply are clinical methods of eliminating pain from focal areas such as facet joints or myofascial trigger points. When a particular joint is determined to be the source of pain, long-term relief can be sought by directing therapeutic interventions at that joint. The anatomic accessibility of the most common pain sources of low back pain make diagnostic blocks and therapeutic instillation of corticosteroids particularly appealing. If used, their potential benefit for the individual case needs to be carefully weighed. They should be used to facilitate more aggressive conservative care and not as an isolated treatment. Certainly, if response to corticosteroids does not occur after the first injection, no further administration of corticosteroids is indicated.

The safety of gastrostomy in patients with Crohn's disease

OBJECTIVE

To evaluate the safety of gastrostomy tube placement in patients with Crohn's disease.

METHODS

We retrospectively reviewed the charts of 25 patients with Crohn's disease who underwent surgical or endoscopic gastrostomy tube placement. Additional follow-up information was obtained by contacting the patients by telephone.

RESULTS

Twenty-five patients with Crohn's disease underwent either surgical or percutaneous gastrostomy tube placement for prolonged enteral nutrition or gastric decompression after abdominal surgery. Gastrostomies were placed without difficulty in all cases. No major complications occurred after the procedures. Minor complications occurred in five patients, including one case of local wound infection, one case of persistent pain at the gastrostomy site, and three cases of peristomal leakage. These minor complications occurred in 22% of those who underwent percutaneous gastrostomy tube placement and 16% of those who underwent surgical gastrostomy. There was a higher incidence of minor complications in those who underwent gastrostomy for gastrointestinal decompression than in those who underwent the procedure for nutritional supplementation (14% versus 3.5%). A prior history of fistula formation did not predispose to complications related to gastrostomy placement. After gastrostomy tube removal, rapid closure of the site occurred in 96%. No cases of gastrocutaneous fistula formation occurred during follow-up, which ranged from 45 days to 8.7 yr (mean = 2.6 yr).

CONCLUSIONS

We conclude that gastrostomy placement is safe in patients with Crohn's disease and does not result in an increased incidence of peristomal disease or formation of prolonged gastrocutaneous fistulas after gastrostomy tube removal.

Impact of Travel-Related Health Impairments

Background: Few recent data exist on the impact of travel-related health problems. Methods: A cohort study was conducted with follow-up by questionnaire of 2567 persons who had consulted the Zurich University Travel Clinic for travel health advice prior to visiting a developing country or eastern Europe. Of those questioned, 2109 (82.2%) could be evaluated. Results: More than one-third (800; 37.9%) had a health impairment, mainly illness leading to medical consultations in 224 (10.6%) individuals. Incapacitation was reported by 303 (14.4%) travelers, accounting for 2% of the total time abroad. The most frequent reasons for incapacitation were diarrhea and the common cold, particularly when accompanied by fever. Some 57 (7.1%) travelers consulted a doctor while abroad, and more than twice as many did so after returning home. Conclusions: This survey illustrates that despite efforts of travel medicine, the attack rate of health impairments remains virtually unchanged compared to 20 years ago. It provides one of the first overviews of incapacitation in travelers. To reduce the duration of incapacitation, one may wish to consider a travel kit which allows the patient self therapy for frequent and uncomplicated ailments.

Use of conscious sedation for lower and upper gastrointestinal endoscopic examinations in children, adolescents, and young adults: a twelve-year review

BACKGROUND

Over the past decade, many pediatric endoscopists have replaced general anesthesia with conscious sedation. Sedation is commonly used to minimize discomfort.

METHODS

To evaluate the safety and efficacy of conscious sedation we reviewed 2711 reports of lower and upper gastrointestinal endoscopic examinations performed in 2026 patients between July 1981 and December 1992.

RESULTS

Intravenous sedation was accomplished using meperidine and diazepam (914 examinations, 35%) or meperidine and midazolam (1427 examinations, 55%). Single agents were used for 83 examinations (3%), and 96 examinations (3.5%) were performed with the patient under general anesthesia. In the lower endoscopy group sedated intravenously (n = 713), the cecum was reached in 82% of examinations. The procedure could not be completed in 17 cases in which patients were uncooperative despite sedation. In the upper endoscopy group sedated intravenously (N = 1653), all but 91 endoscopies were completed to the descending duodenum. Esophagoscopy had been planned in 76% of these procedures. Minor complications occurred in 7 patients (0.3%). This included two episodes of significant oxygen desaturation that responded to oxygen administration and narcotic reversal. A major complication occurred in 1 patient (0.04%) who had a gastric perforation during esophageal dilation over a defective guide wire. There were no deaths, episodes of cardiorespiratory arrest, or pulmonary aspirations in our series. The combined major and minor complication rate was 0.3%.

CONCLUSIONS

Intravenous conscious sedation is safe and effective in children undergoing endoscopic examination of the gastrointestinal tract. Selected patients will require general anesthesia.

Verification of the position of pedicle screws in lumbar spinal fusion

Medial or lateral pedicle screw penetration with the potential to affect neural structures in a wellknown and frequent problem associated with posterior spinal fusion. We evaluated the placement of pedicle screws (n = 141) in 36 patients following posterior lumbar spinal fusion with Socon or Kluger instrumentation via a lateral transpedicular approach. The examination was based on CT and MR images performed after removal of the instrumentation, on average 1 year after implantation. We found seven pedicle screws with lateral cortical penetration of the pedicle and five screws with medial cortical penetration of the pedicle (8.5% pedicle penetration overall). No severe radicular complications accompanied these pedicle penetrations. The mean insertion angles of the pedicle screws at the L4 level were 22.6 degrees and 23.1 degrees for the left and the right side, respectively. At the L5 level the mean insertion angle was 20.5 degrees on the left side and 21.5 degrees on the right, and at the S1 level the mean angle was 16.2 degrees on the left and 15.2 degrees on the right. The results of this study indicate that the lateral transpedicular approach is a safe procedure for pedicle screw insertion.

Preparation for emergency relief after biological warfare

Upon invitation by the World Health Organization during the Gulf War, a task force "Scorpio" independent from the nations involved in the armed conflict was formed whose task was to determine whether, which and to what extent biological warfare agents had been used. risk assessment concluded that anthrax and Clostridium botulinum toxin were the major risks. The 21 civilian experts had rapidly to decide on the doctrine of operation, to assemble material which could be used and to be immunized or protected otherwise against the potential risks. Biological warfare agents may be used anywhere any time, be it by terrorists or during open or clandestine hostilities. The general population cannot rely on the military to take care of civilian relief, thus international and national organizations may wish to establish similar task forces basing on the "Scorpio" model on a national or regional basis.

Tolerance of mefloquine by SwissAir trainee pilots

Due to presumed adverse performance impact, a World Health Organization clause currently restricts the use of mefloquine malaria chemoprophylaxis in individuals requiring fine coordination and spatial discrimination. We conducted a double-blind, placebo-controlled, cross-over study to quantitatively assess the effects of mefloquine at steady state on performance in 23 trainee airline pilots. Flying performance was assessed using a flight simulator, psychomotor function was evaluated, sleep and wake cycles were monitored, and symptoms and moods were assessed using standardized questionnaires. A simplified postural sway meter recorded sway in three test positions. In the mefloquine loading dose phase, there was one withdrawal due to dizziness, diarrhea, and flu-like symptoms, and three volunteers reported nonserious, sleep-related adverse events. There was no significant difference in flying performance, psychomotor functions, or mean sway for any test position. Nonsignificant reductions in mean total nocturnal sleep (mefloquine = 450 min versus placebo = 484 min) and poorer sleep quality were detected in the mefloquine phases. The mood findings indicated a predominance of positive states, with vigor the predominant mood in all phases. No significant performance deficit was documented under laboratory conditions during use of mefloquine at steady state.

[Control measures in an influenza pandemic in Switzerland]

As an influenza pandemic is to be expected, contingency plans are being developed in industrialized nations. During the interpandemic phase the responsibilities are clearly defined and no shortage occurs with respect to vaccines and drugs. In contrast, a lack of material and of infrastructure must be expected in a pandemic which will stress public health and disrupt social and business life. This plan illustrates how with the available means we should attempt to the best possible primarily to reduce premature mortality, secondarily to diminish morbidity and to maintain essential public services and security. Options are described, for instance how an increased production of vaccine already during the interpandemic phase would probably reduce the impact of a pandemic.

Molecular cloning and sequence analysis of two cDNAs coding for putative anionic trypsinogens from the colonial Urochordate Botryllus schlosseri (Ascidiacea)

Botryllus schlosseri is a colonial marine invertebrate that belongs to the subphylum Urochordata. Previously we analyzed the activity of a serine protease in this species, and cloned a tunicate chymotrypsin-like molecule. In the present study we further analyzed the protease activity of this animal, and found biochemical evidence also for specific trypsin-like activity. Subsequently we utilized a degenerate polymerase chain reaction (PCR) primer to clone two B. schlosseri cDNAs coding for two different putative trypsinogens, each 243 amino acids long, that differ within the coding region in 42 amino acids and 99 nucleotides. Both clones feature the characteristics of animal anionic trypsinogens. Sequence analysis of the tunicate putative trypsinogens revealed the invertebrate characteristics of three disulfide bridges, and higher similarity to invertebrate than to vertebrate trypsinogens. We therefore propose that the typical characteristics of vertebrate trypsinogens evolved after the divergence of Urochordates and Cephalochordates.

A galectin links the aggregation factor to cells in the sponge (Geodia cydonium) system

The cDNA for the full-length lectin from the marine sponge Geodia cydonium was cloned. Analysis of the deduced aa sequence revealed that this lectin belongs to the group of galectins. The full-length galectin, which was obtained also in a recombinant form, has an M(r) of 20,877; in the processed form it is a 15 kDa polypeptide. The enriched aggregation factor from G.cydonium also was determined to contain, besides minimal amounts of the galectin, a 140 kDa polypeptide which is involved in cell-cell adhesion. Monoclonal antibodies have been raised against this protein; Fab' fragments prepared from them abolished cell-cell reaggregation. Cell reaggregation experiments revealed that the aggregation factor is an essential component in the aggregation process but it requires likewise the presence of the galectin. Antibodies against the galectin blocked the aggregation factor-mediated cell adhesion. A plasma membrane component was identified (a 29 kDa polypeptide) which interacted with the aggregation factor in the presence of galectin; binding could be blocked both by antibodies against the galectin as well as against the aggregation factor. Immunohistochemical analysis revealed that spherulous cells contain the galectin but not the aggregation factor. By laser scanning microscopy, it is shown that both the aggregation factor and the galectin are located at the rim of the cells. From these data we conclude that the G.cydonium aggregation factor binds to the cells via a galectin bridge.

Malaria Prophylaxis in Different Age Groups

Background: There is a perceived increased health risk in senior visitors to malaria endemic countries. Methods: The authors sought to compare effectiveness and tolerability of malaria chemoprophylaxis in senior travelers (>=60 years) with those in younger travelers (20-59 years). The "Malpro 2" database consists of more than 100,000 questionnaires completed by travelers on charter planes returning from East Africa to Europe during July 1988-December 1991. Among them, 9106 (9.1%) of the travelers were 60 years or older, and 84,562 (84.6%) of the travelers reported to be 20-59 years. Variables of demography, travel data, and the effectiveness and tolerability of chemoprophylaxis were compared in the two subgroups. Results: Malaria in Africa was reported by 8 (1/1000) elderly travelers and by 189 (2.2/1000) travelers aged 20-59 years. Adjusting for age, sex, prophylaxis, and duration of stay in Africa in a logistic regression model, malaria was significantly more frequent in younger than in senior travelers (p<.05). Any travel-associated illness was reported by 7.0% in the senior age group and by 13.6% in the younger age group (p<.05). The rates of travelers who indicated they had "side effects" attributable to malaria prophylaxis varied between 9.7% in the elderly and 15.5% in the younger travelers (p<.05). Conclusion: Senior travelers tolerate malaria chemoprophylaxis and visits to the tropics at least as well as younger travelers.

Regulation of motility of cells from marine sponges by calcium ions

Sponges are known not to contain muscle and nerve cells. Since sponge cells are characterized by high motility we determined the effect of intracellular calcium ion concentration ([Ca2+]i) on their motility. Addition of the Ca2+ ionophore ionomycin to dissociated cells from the marine sponge Suberites domuncula caused in Ca(2+)-containing artificial seawater (ASW) an increase in motility from 0.2 micron/min (absence of the ionophore) to 3.7 microns/min (presence of ionomycin). When the experiments were performed in Ca(2+)-free medium, no effect of ionomycin could be observed. In parallel experiments the changes of [Ca2+]i using the dye Fura-2 were measured. The experiments revealed that ionomycin causes an influx of Ca2+ into the cytosol of cells suspended in Ca(2+)-containing artificial seawater. In contrast, if cells were suspended in Ca(2+)-free artificial seawater, no increase of [Ca2+]i occurred. Incubation of cells in the presence of inhibitors, specific for endoplasmatic Ca(2+)-ATPase in mammals such as thapsigargin, cyclopiazonic acid, or 2,5 di-t-butylhydrochinone, did not influence the [Ca2+]i if cells were suspended in Ca(2+)-free artificial seawater. From these data we conclude that the [Ca2+]i is primarily regulated through channels in the plasma membrane. In addition we summarize experimental evidence indicating that the [Ca2+]i is involved in the control of cell motility. From the marine sponge Geodia cydonium a partial sequence of the myosin cDNA has been cloned. The deduced amino acid sequence comprises highest homology to nonmuscle myosin type II found in higher invertebrates and vertebrates. Taken together, these data show that the [Ca2+]i level in sponge cells can be modulated by incubation with ionomycin. An increase of the Ca2+ level parallels with higher motility of cells, suggesting an activation of Ca(2+)-dependent protein kinases of myosin type II. Investigations on the ionomycin-activated influx of Ca2+ into the cytosol revealed that predominantly the Ca2+ channels in plasma membrane control the level of [Ca2+]i.

Polymorphism in the immunoglobulin-like domains of the receptor tyrosine kinase from the sponge Geodia cydonium

Sponges [Porifera] are the phylogenetically oldest phylum of the Metazoa. They are provided with both cellular and humoral allorecognition systems. The underlying molecules are not yet known. To study allorecognition in sponges we first determined the frequency of graft rejection in a natural population of the marine sponge Geodia cydonium. We then determined, for the first time at the molecular level, the degree of sequence polymorphism in segments of one molecule which may be related to sponge allorecognition and host defense: the Ig-like domains from the receptor tyrosine kinase [RTK]. Thirty six pairs of auto- and allografts were assayed, either by parabiotic attachment or insertion of grafts. All of the autografts fused, while only two allografts fused and 34 pairs were incompatible. Rejection among the parabiotic allografts was characterized by the formation of a collagenous barrier, while the allografts that were inserted into the host underwent destruction. At the molecular level we first cloned to completion the 5'-end of sponge RTK, which displays a Pro-Ser-Thr-rich sequence; this is thought to act as a module of cell adhesion proteins. Then we analyzed RT-PCR products of amplification across the two Ig-like domains of RTK (about 500 bp), from two pairs of fusing sponges and one pair of rejecting sponges. High levels of polymorphism were recorded, including 18 nucleotide-substitution positions and a tri-nucleotide deletion, which translate into 13 polymorphic amino acid positions. Two of the six sponges were scored as heterozygotes. Among 9 informative polymorphic sites that were tested for linkage disequilibrium, 11 pairwise comparisons were found to be significant, implying the possibility of distinguishable alleles in this locus. To the best of our knowledge this is the first report of polymorphism in Ig-like domains of a receptor from invertebrates that may be associated with allorecognition. This data attests also that fusion in sponges is not confined to genetically identical individuals.

Mefloquine tolerability during chemoprophylaxis: focus on adverse event assessments, stereochemistry and compliance

This longitudinal study of travellers to Africa taking mefloquine (MQ) chemoprophylaxis aimed to quantify and assess non-serious adverse events (AE) occurring during short-term prophylaxis and relate these to concentrations of racemic MQ, its enantiomers and metabolite. A total of 420 volunteers (52% F) participated. AEs with some impact on activities were reported by 11.2% of participants including 7.9% of neurological/psychiatric symptoms. Women were more likely to report AEs (P = 0.02). The standardized questionnaires used showed more pathological indicators in travellers who reported subjective AE with significantly more dizziness, distress, sleep disturbances and a high total mood disturbance (TMD) in the AE group. There was, however, no significant performance deficit in computerized psychomotor tests in those experiencing AE. Furthermore, no significant differences were observed in enantiomer ratios, metabolite concentrations, or racemic MQ levels in participants with or without AEs suggesting that these factors are not the main predictors of mefloquine intolerability.

Vaccinations for travelers: new technology, new vaccines, new strategies

To improve compliance with vaccines and to achieve greater efficacy, a new generation of vaccines is needed. These may be combinations of existing vaccines, but much more exciting are prospects of new formulations with controlled release and novel adjuvants. The ultimate goal is one single injection (or, even better, oral dose, but this is difficult to achieve) in childhood, and another when subjects such as travelers start to expose themselves to specific infectious risks.

Hepatitis A infection in aircrews: risk of infection and cost-benefit analysis of hepatitis A vaccination

BACKGROUND

Since a hepatitis A vaccine (HAV) with long-lasting efficacy has become available, its indication in airline crews needs to be determined.

HYPOTHESIS

Destinations in developing countries are a risk factor for hepatitis A infection in airline crews, and vaccination is cost-beneficial.

METHODS

Retrospective analysis was performed for all Swissair medical files for the period 1987-91. Denominator and cost data were obtained by the personnel department, and a cross-sectional seroepidemiological survey was performed in 734 Sabena staff.

RESULTS

Among 3,322 Swissair crewmembers who spent an average of 45 nights in developing countries, 22 hepatitis A infections occurred. For the non-immune crewmembers, the overall annual incidence rate was 1.53 per 1000, whereas the incidence rate while staying in a high risk country was 12.2 per 1000. Cockpit crews with destinations limited to Europe had a rate of zero. Male flight attendants had a threefold higher rate as compared to female flight attendants or pilots. In Sabena, anti-HAV seroprevalence was 33.3%. Increased rates were observed in male as compared to female flying crews and in employees stationed abroad, whereas flying personnel had no higher rate than ground personnel. Simplified comparison of cost of infection and cost of vaccination indicates that vaccination may be cost-saving to the airline company for both male flight-attendants and pilots.

CONCLUSIONS

Hepatitis A vaccination may be recommended to staff stationed in high risk countries and to flying crews with such destinations.

[Routine immunization of infants in the Canton of Zurich]

At present there is a shortage of data regarding the rate of routine immunization in Swiss children. To address this deficit, a representative cross sectional study was conducted in the Canton of Zurich with 210 children aged between 24 and 36 months. Data was taken from the individual official vaccination certificates. 178 vaccination certificates (55.1% female and 44.9% male) were evaluated, corresponding to a response rate of 84.8%. With children of foreign nationalities, the response rate was 66.7%, whereas the response rate of Swiss children was 90.6% (p < 0.001). The response rate of children of a European nationality outside the European Union was especially poor (33.3%). The immunization rate with three doses of diphtheria, tetanus and poliomyelitis vaccines was 99.4%, and that of the pertussis vaccine was 93.3%. With the vaccines for measles, mumps and rubella the rates were 80.3%, 78.1% and 77.5% respectively. Vaccination rate against Haemophilus influenzae type B was 74.7% with two doses, and 61.2% with three doses. The timing and the number of doses of the vaccines used for infants in the Canton of Zurich were satisfactory. However, the vaccination rate for measles, mumps and rubella is inadequate. Attention should be paid to this problem and also to possible insufficient care of foreign children.

[Video laparoscopic transperitoneal exposure of the lumbar spine for ventral fusion]

Video-laparoscopic transperitoneal ventral fusion of the lumbar spine using the Bagby-and-Kuslich (BAK) interbody fusion system combines the advantages of the conventional transperitoneal approach with the well-known advantages of minimally invasive surgery. According to our experience it is a safe procedure with an acceptable operating time, little postoperative pain, fast recovery and a short postoperative stay in hospital. Long term results need to be observed and further studies made.