Present development concerning antimalarial activity of phospholipid metabolism inhibitors with special reference to in vivo activity

The systematic screening of more than 250 molecules against Plasmodium falciparum in vitro has previously shown that interfering with phospholipid metabolism is lethal to the malaria parasite. These compounds act by impairing choline transport in infected erythrocytes, resulting in phosphatidylcholine de novo biosynthesis inhibition. A thorough study was carried out with the leader compound G25, whose in vitro IC50 is 0.6 nM. It was very specific to mature parasites (trophozoïtes) as determined in vitro with P. falciparum and in vivo with P. chabaudi -infected mice. This specificity corresponds to the most intense phase of phospholipid biosynthesis activity during the parasite cycle, thus corroborating the mechanism of action. The in vivo antimalarial activity (ED50) against P. chabaudi was 0.03 mg/kg, and a similar sensitivity was obtained with P. vinckei petteri, when the drug was intraperitoneally administered in a 4 day suppressive test. In contrast, P. berghei was revealed as less sensitive (3- to 20-fold, depending on the P. berghei-strain). This difference in activity could result either from the degree of synchronism of every strain, their invasion preference for mature or immature red blood cells or from an intrinsically lower sensitivity of the P. berghei strain to G25. Irrespective of the mode of administration, G25 had the same therapeutic index (lethal dose 50 (LD50)/ED50) but the dose to obtain antimalarial activity after oral treatment was 100-fold higher than after intraperitoneal (or subcutaneous) administration. This must be related to the low intestinal absorption of these kind of compounds.(ABSTRACT TRUNCATED AT 250 WORDS)

Three-point transformation for integration of multiple coordinate systems: applications to tumor, functional, and fractionated radiosurgery stereotactic planning

The accuracy of an optimized three-point transformation method and its usefulness for integrating multiple independent coordinate systems has been described. Such integration can be implemented to accomplish complex stereotactic procedures which may require the use of multiple image data sets and combinations of frame-based and frameless stereotactic systems. This report details the application of an optimized transformation for intracranial lesion biopsy and/or resection, radiofrequency pallidotomy for treatment of Parkinson's disease, and fractionated stereotactic radiosurgery in a total of 68 patients. For approach to intracranial lesions, a noninvasive definition of image coordinate systems with multiple radiodense scalp markers was cross-registered with a standard stereotactic guidance system. This method allowed for elective acquisition of stereotactic image sets without requiring head frame fixation until the time of the operative procedure. In planning pallidotomy procedures, spatial cross-registration of CT and MR image coordinates were performed to target the posteroventral pallidum. CT coordinates were defined by the standard picket fence algorithm while MR images were referenced with multiple scalp markers. The addition of MR data sets improved anatomic resolution in the regions of the basal ganglia and commissures. Fractionated radiosurgery was accomplished by cross-registration of CT, MR, and plain radiographs using BRW localizers coupled with multiple scalp markers. A daily check of target positioning was performed with the BRW angiograph localizer. The average calculated error was 2.83 mm with a standard deviation of 1.66 mm which remained within the average scan slice thickness of 3.63 mm. In all cases surgical targets were reached without complication.(ABSTRACT TRUNCATED AT 250 WORDS)

Is there a relationship between autoantibodies and silicone-gel implants?

The present study was conducted to determine if 200 patients with silicone-gel implants demonstrated elevated levels of autoantibodies, compared with a similar group of 100 age-matched control subjects without breast implants. These results were then compared with 29 patients who had demonstrated implant rupture. Differences in the frequency of autoantibody levels were determined by the chi-squared test. Differences in autoantibody titers were determined by Wilcoxon's signed rank test. Differences were considered significant with p > 0.05. The prevalence of a positive antinuclear antibody (ANA) test (dilution 1:100) in the 200 patients with breast implants was 26.5% compared with 28% in the 100 control subjects. In 29 patients with implant rupture, only 17.2% tested ANA positive. These values were not significantly different. In addition, there were no significant differences between the ANA titers of positive patients in each group. In each of the three groups, all patients who tested ANA positive were analyzed to assess the frequency and titer of other autoantibodies, including anti-DNA, anti-cardiolipin, anti-SSA, anti-SSB, anti-SM, anti-RNP, and anti-Scl-70. There were no significant differences between the frequency or titer of any of these autoantibody levels in each of the three groups of patients. These studies strengthen the concept that there is no conclusive evidence that silicone-gel implants are related to the development of connective tissue disease.

Hematopoietic recovery following high-dose combined alkylating-agent chemotherapy and autologous bone marrow support in patients in phase-I clinical trials of colony-stimulating factors: G-CSF, GM-CSF, IL-1, IL-2, M-CSF

Hematopoietic recovery in 115 patients with metastatic breast cancer or metastatic melanoma, enrolled in phase-I studies of recombinant growth factors while undergoing treatment with high-dose chemotherapy with autologous bone marrow support, was examined with assays of bone marrow progenitor cells and peripheral blood progenitor cells, and by evaluation of peripheral blood counts. Groups of patients receiving hematopoietic cytokine support [with interleukin-1 (IL-1), interleukin-2 (IL-2), granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), or monocyte CSF (M-CSF)] post marrow infusion were compared with contemporaneous control patients not receiving growth factor support. Patients receiving GM-CSF demonstrated statistically significant increases in the growth of granulocyte/macrophage colony-forming units (CFU-GM) in the bone marrow and peripheral blood compared with control patients. The effect of GM-CSF was dose dependent in the early period post marrow infusion (day +6) with bone marrow CFU-GM colonies at doses 8-16 micrograms/kg/day 34 times those measured in controls. Significant increases in bone marrow multipotential progenitor cells (CFU-GEMM) were seen in patients receiving GM-CSF day +21 post marrow infusion. Patients receiving IL-1 demonstrated significant increases in bone marrow CFU-GM at day +21, maximal at dosages of 24-32 ng/kg/day. There were no significant increases in burst forming unit-erythroid (BFU-E) among any study group. Patients receiving G-CSF had significantly increased absolute neutrophil counts (ANC) and total white blood cell counts (WBC) by day +11 post transplant compared with control patients. Patients receiving GM-CSF demonstrated significantly increased WBC (greater than 2000/mm3) at day +11 and ANC greater than 500/mm3 at day +16. Optimal dose of G-CSF and GM-CSF to stimulate neutrophil recovery post transplant was 4-8 micrograms/kg/day and 8-16 micrograms/kg/day, respectively. Platelet recovery did not differ among the six study groups. These data demonstrate accelerated myeloid recovery after high-dose chemotherapy and autologous bone marrow support in patients receiving either G-CSF or GM-CSF. Moreover, GM-CSF and IL-1 stimulate myelopoiesis at the level of bone marrow CFU-GM, while G-CSF causes earlier neutrophil recovery peripherally.

ELISA for detection of anti-Giardia specific IgM: response in serum

Infection with Giardia lamblia (G. duodenalis, G. intestinalis) is common all over the world, especially in children. Traditional diagnosis by faecal microscopy has only moderate sensitivity; serological tests, although not always positive, are acceptable to patients and useful in epidemiological studies. We show here that serum IgM separated by column chromatography and assayed by an indirect ELISA test can be a useful tool for the diagnosis of giardiasis. One hundred and thirty-nine positive sera (based on a single faecal examination), and 97 negative serum samples from Riyadh, Saudi Arabia, were examined. Taking positive results as being 2 s.d. above the mean of the controls, there were 117 positive results among the microscopically negative controls (3% false positives). The sensitivity of the test was 84% and the specificity 97%; the predictive value of a positive result is 97.5% and of a negative one 81%.

The chemotherapy of rodent malaria. LI. Studies on a new 8-aminoquinoline, WR 238,605

WR 238,605, a novel 3-phenoxy-substituted 8-aminoquinoline, possesses causal prophylactic, blood schizontocidal and gametocytocidal activity against rodent malaria parasites. Against the asexual, intra-erythrocytic stages of drug-sensitive Plasmodium berghei N strain, it is about nine times as active as primaquine (PQ). It is from four to 100 times as active as PQ against lines of P. berghei or P. yoelii that are resistant to currently used antimalarials. WR 238,605 is three times as active as PQ against the pre-erythrocytic stages of P. y. nigeriensis but it has very poor gametocytocidal action and no sporontocidal activity against this parasite. In combination with chloroquine (CQ), WR 238,605 and PQ display a synergistic or 'resistance-reversing' action against CQ-resistant P. yoelii NS parasites. No such effects are seen when WR 238,605 is deployed with mefloquine against a mefloquine-resistant line or with artemisinin against an artemisinin-resistant line and it appears to be antagonistic to halofantrine against a halofantrine-resistant parasite. It is suggested that WR 238,605 is a good candidate compound for clinical trials against polyresistant P. falciparum, possibly in combination with CQ.

Haploidentical bone marrow stem cell transplantation in human severe combined immunodeficiency

From May 1992 to March 1993, 50 infants with severe combined immunodeficiency (SCID) were given bone marrow transplants at Duke University Medical Center. None received chemotherapy for conditioning or for graft-versus-host disease (GVHD) prophylaxis. Forty-one received haploidentical parental marrow depleted of T cells by soybean lectin and sheep red blood cell resetting, and nine received HLA-identical marrow. Forty (80%) survived from 1 week to almost 11 years posttransplantation, including nine of nine (100%) HLA-identical marrow recipients and 31 of 41 haploidentical recipients. T-cell function was present within 2 weeks after transplantation of unfractionated HLA-identical marrow, but not until 3 to 4 months after T-cell-depleted haploidentical marrow stem cells. All 37 patients who are more than 4 months posttransplantation have good T-cell function, and all but one have 100% donor T cells. B-cell function developed slowly or not at all in some recipients of haploidentical marrow. Fourteen (four HLA-identical and 10 haploidentical recipients) have some donor B cells; 19 patients are receiving intravenous immune globulin (IVIG) therapy.

Development and characterization of an adriamycin-resistant sw480 human colon adenocarcinoma cell-line

An adriamycin resistant Sw480 human colon adenocarcinoma cell line (Sw480 Adr) was developed. Characteristics of the Sw480 Adr cells were compared with that of the parent Sw480 (Sw480 WT) cell line. Sw480 Adr cells were cross-resistant to mitoxantrone but not to cisplatin. Glutathione S-transferase enzyme activity as well as glutathione S-transferase pi content were increased 1.5 fold in the resistant cells, whereas P-170 glycoprotein content was increased several hundredfold. Sw480 Adr cells could be partly resensitised towards adriamycin by prior incubation with verapamil (1.65-3.3 mug/ml) and completely resensitised by cyclosporin A (2.5-5.0 mug/ml). Incubation of Sw480 Adr cells with various concentrations of adriamycin (200-1600 nM) during one week, did not change the P-170 glycoprotein levels. In addition, Sw480 Adr cells cultured in adriamycin-free medium for ten weeks (and passaged each week), showed no significant change in P-170 glycoprotein content. These results indicate that the most important mechanism for adriamycin resistance in Sw480 Adr human colon adenocarcinoma cells is overexpression of the P-170 glycoprotein, an ATP-driven drug efflux pump located in the plasma membrane. This overexpression of the P-170 glycoprotein in Sw480 Adr cells does not seem to be reversible.

Ultrasound analysis of 150 patients with silicone gel breast implants

One-hundred fifty patients with silicone gel breast implants were investigated using ultrasound (US) studies, to assess the integrity of their implants. US testing demonstrated 8 patients (5.33%) with implant rupture, which was subsequently confirmed at surgery. A further 4 patients were "false negatives," wherein they presented with normal US tests, but at subsequent surgery, demonstrated secondary alterations in their implant envelopes. Two of these patients demonstrated profound local silicone gel "bleed," whereas the 2 others had frank implant rupture. There was also one "false positive" patient. The total known prevalence of patient implant alteration was therefore 12, i.e., 10 with ruptures and 2 with profound local gel "bleed," in 150 patients (8.0%). Five of the 10 patients with ruptured implants had undergone multiple closed capsulotomies in the past. The mean time of diagnosis after implant insertion was 8.5 years (range, 2.0-18 yr). US analysis may provide a safe, simple, inexpensive, noninvasive tool to assist in the identification of ruptured silicone gel breast implants. There were significant limitations with technique, however, in that there were 4 false negatives, and 1 false positive result, and US analysis was not helpful in diagnosing profound silicone gel bleeds.

Heterogeneity of cutaneous leishmaniasis with emphasis on the Old World

Leishmaniasis of the integument which may result from infection with a number of different species of Leishmania can be primary, or can arise as a late manifestation of systemic infection of the reticuloendothelial organs (kala-azar). Infection of the skin and/or mucosae assumes many different clinical forms which are reviewed here. The immune response is essentially a cell-mediated one. Even left untreated, the majority of tegumentary lesions will eventually self-heal but the process may be very prolonged and severe scarring can result. The main features of diagnosis, prevention and treatment are discussed. No vaccines are generally available at present. Organic pentavalent antimonials remain the drugs of choice.

Burns in the disabled

A retrospective analysis of 812 patients admitted to the Ross Tilley Burn Centre between 1984 and 1992 resulted in 37 cases of burn injuries which were directly related to premorbid disabilities. The majority of these burns (83.8 per cent) occurred in the patient's home, most commonly as scald injuries in the bath tub, the shower, or following hot water spills. Nineteen patients were male, 17 were female. The median age was 58 years. Six patients had spinal cord disorders: four had traumatic cord damage, two had spina bifida. Six patients had seizure disorders. Five of these patients had been taking anti-seizure medications, but all had subtherapeutic blood levels on admission to hospital. Two patients had diabetes mellitus with peripheral neuropathies. Thirteen patients had four miscellaneous neurological disorders, including: tardive dyskinesia (two), CVA (four), Parkinson's disease (two), Alzheimer's disease (two), cerebral palsy (one), multiple sclerosis (one) and blindness (one). Three patients had a diagnosis of syncope. Two patients had emphysema, and four were morbidly obese. The average length of stay (LOS) for the disabled patients was 27.6 days for a median burn size of 10 per cent body surface area (BSA), compared to an average LOS for the general population of 25.7 days for a larger median burn size of 21 per cent BSA. The mortality rate was also much higher in the disabled population (22.2 per cent vs. 6.0 per cent). Most of these burn injuries were preventable. A series of burn prevention guidelines is presented, in an attempt to reduce the incidence of these burn injuries in disabled patients.

Burns caused by flambé foods

From 1978 to 1990, five patients were admitted to the hospital for treatment of burns that were sustained during the preparation of flambé foods in restaurants. Three patients were patrons, and two were waiters. The average body surface area involved was 14% (range 10% to 18%). The average area of full-thickness burn was 3% (0% to 10%). All patrons required long-term psychologic support and were involved with lengthy and expensive litigation proceedings. The two waiters lost a total of 5 months from work. Although these injuries are quite rare, it is hoped that they can be totally prevented by adherence to certain safety guidelines.

The chemotherapy of rodent malaria. L. The activities of some synthetic 1,2,4-trioxanes against chloroquine-sensitive and chloroquine-resistant parasites. Part 3: Observations on 'Fenozan-50F', a difluorinated 3,3'-spirocyclopentane 1,2,4-trioxane

A novel difluorinated 3,3'-spirocyclopentane 1,2,4-trioxane ('Fenozan-50F') is a potent blood schizontocide against drug-sensitive and drug-resistant rodent malaria parasites. It also exerts some action against pre-erythrocytic schizogony, is a potent gametocytocide, and exerts a direct sporontocidal effect in infected mosquitoes. In the '4-day test' the ED90s are 6.8 and 6.0 mg/kg/day for four consecutive days by the subcutaneous and oral routes respectively against drug-sensitive Plasmodium berghei N, and 6.3 and 25 mg/kg against chloroquine-resistant P. yoelii NS in vivo. By the oral route against P. berghei N infection in mice, Fenozan-50F is about half as active as arteether but nearly three times as active as sodium artesunate. The activity of Fenozan-50F is retained against a wide spectrum of drug-resistant parasite lines, although those highly resistant to quinine or to artemisinin are less responsive at the ED90 level. At the ultrastructural level the compound, when administered to infected mice, causes marked changes in the membranes and ribosomes of trophozoites and young schizonts and of immature gametocytes, although few changes are apparent in mature gametocytes. Its toxicity appears to be very low when it is administered to mice by either the oral or subcutaneous route. Fenozan-50F is considered to be a good candidate for eventual use as a therapeutic agent for infection with polyresistant malaria in man.

Capsular contracture simulating myocardial infarction on ECG

A patient is presented with severe bilateral class IV capsular contractures who presented 16 years after prepectoral breast augmentation with a "septal infarct" pattern on ECG. This abnormal ECG proved to be an artifact caused by unavoidable misplacement of the V2 and V3 leads because of the severe capsular contracture. Following open capsulotomy, normal anatomic lead placement was possible, and a normal ECG was produced.

Pathology of the pancreas in bone marrow transplant patients

Review of 51 autopsy cases of patients receiving high-dose chemotherapy followed by bone marrow transplantation revealed a high prevalence of pancreatic ductal and acinar changes compared with control groups. Forty-five percent (23 of 51) of bone marrow transplant cases had squamous metaplasia of the pancreatic ducts compared with 10% of randomly selected control cases. Although squamous metaplasia was more common in bone marrow transplant patients receiving chemotherapy, it was not associated with whole body radiation, allogeneic transplantation, or specific drugs. Squamous metaplasia was more common in patients dying 30 days or more after transplantation. Dilatation of the pancreatic acini was present in 78.4% of transplant cases, 35.0% of control cases, and 50.0% of a group of 12 breast cancer patients treated with conventional doses of chemotherapy without bone marrow transplantation. This lesion was associated with uremia. Oncocytic change of the acinar epithelium was present in 52.9% of transplant cases, no control cases, and 41.7% of breast cancer cases. Squamous metaplasia of the pancreas is common in bone marrow transplant patients receiving high-dose chemotherapy and may be a late manifestation of toxic injury to the ducts. A high prevalence of acinar dilatation was associated with terminal uremia. Oncocytic change of acinar epithelium was associated with chemotherapy.

The chemotherapy of rodent malaria. XLIX. The activities of some synthetic 1,2,4-trioxanes against chloroquine-sensitive and chloroquine-resistant parasites. Part 2: Structure-activity studies on cis-fused cyclopenteno-1,2,4-trioxanes (fenozans) against drug-sensitive and drug-resistant lines of Plasmodium berghei and P. yoelii ssp. NS in vivo

The activity of 51 synthetic cis-fused cyclopenteno-1,2,4-trioxanes has been examined against drug-sensitive and chloroquine-resistant malaria parasites in vivo. Some of them display high levels of blood schizontocidal activity when administered orally or subcutaneously. They retain their activity against lines of parasites that are resistant to widely differing antimalarials such as 4-aminoquinolines, aminoalcohols, dihydrofolate reductase inhibitors and artemisinin. The most potent compound of the present series is cis-(+/-)-4a,7a-dihydro-6,7a-di(p-fluorophenyl)spiro [cyclopentane-3,3'-7H-cyclopenta-1,2,4-trioxin], otherwise known as Fenozan-50F.

The chemotherapy of rodent malaria. XLVIII. The activities of some synthetic 1,2,4-trioxanes against chloroquine-sensitive and chloroquine-resistant parasites. Part 1: Studies leading to the development of novel cis-fused cyclopenteno derivatives

The new Chinese antimalarial blood schizontocide, artemisinin, derived from the plant Artemisia annua, displays a high level of activity against polyresistant Plasmodium falciparum. Several synthetic 1,2,4-trioxanes were examined in a search for compounds that exhibit a similar type of action against drug-resistant parasites. This paper, the first of a series, describes the examination of these trioxanes against drug-sensitive and drug-resistant malaria parasites in a rodent model, using artemisinin and arteether as comparison standards. Cis-fused cyclohexeno-1,2,4-trioxanes (10-17) substituted with various side-chains revealed for the most part variable but weak antimalarial activity. On the other hand, cis-fused cyclopenteno-1,2,4-trioxanes (18-19) showed greater activity, 19 showing about 1/30th of the activity of arteether against drug-sensitive Plasmodium berghei in vivo, thereby providing a clue to the structure-activity relationship.

Enzyme-linked immunosorbent assay for the detection of anti-Giardia specific immunoglobulin G in filter paper blood samples

Conventional diagnosis of infection with Giardia duodenalis is by faecal examination but the sensitivity of a single examination is low. Serological tests, although not always positive, are more acceptable to patients and are useful in determining the prevalence of giardiasis in large populations. We show here that blood collected on filter paper and dried provides an excellent source of material for enzyme-linked immunosorbent assays; using samples from a group of 88 stool-negative and 45 positive patients, the optimum results were obtained by taking the control mean optical density plus one standard deviation as the negative/positive cut-off value. The sensitivity was 91% (2/45 false negatives), and the specificity 95% (4/88 false positives). This method should be particularly useful for large-scale surveys in developing countries or wherever serological testing is done in central laboratories.

Long-term effects of neonatal bone and joint infection on adjacent growth plates

Review of children with physeal damage from neonatal infection other than the hip at Winnipeg Children's Hospital showed that six patients had residual growth interference from adjacent infection in the bone or joint. Several of the infections involved multiple joints, with growth plate arrest occurring in the distal femoral growth plate in four, in the proximal humerus in four, in the proximal femur in two, in the distal radius in one, and in the distal humerus in one. Although the initial infection was frequently believed to be successfully treated in the neonate, the clinical effect of these infections on the growth plate was not fully appreciated in five of the infants until the children reached a mean age of 9 years. Because growth abnormalities in physeal bars may not be clinically evident for several years after the initial infection has been treated, we recommend that children with bone and joint infections occurring in the first month of life be followed to skeletal maturity, observing the adjacent physis for late tethering.

The chemotherapy of rodent malaria. XLVII. Studies on pyronaridine and other Mannich base antimalarials

The activities of Mannich base antimalarials, including pyronaridine, have been explored against drug-sensitive (Plasmodium berghei N) and chloroquine-resistant (Plasmodium yoelii NS) rodent malaria parasites in vivo. Lines of these parasites have been developed with resistance to pyronaridine, amodiaquine, or WR 228,258. The responses and patterns of cross-resistance of these lines to Mannich bases and other blood schizontocides are inconsistent. It is concluded that some Mannich bases may prove still to be of value inthe treatment of chloroquine-resistant Plasmodium falciparum infection.

Cellular mechanisms of differential action potential duration restitution in canine ventricular muscle cells during single versus double premature stimuli

BACKGROUND

We tested the hypothesis that action potential duration (APD) restitution of normal ventricular muscle cells is different during double premature stimuli (S3) compared with a single premature stimulus (S2). We propose a possible ionic mechanism for such a difference.

METHODS AND RESULTS

Action potentials and isometric tension were recorded simultaneously from isolated canine right ventricular trabeculae (2 x 2 x 10 mm) (n = 35). APD and tension restitution curves (APD) and peak tension versus diastolic interval [DI] of S2 and S3 were constructed by the extrastimulus method during pacing at 1,500 msec. The following results were obtained. 1) The APD restitution curve of S2 was different from that of S3. During the restitution of S2, an early biphasic upward hump was present at short DIs. In contrast, a smooth exponential rise was consistently seen during S3 restitution. 2) Peak tension remained significantly (p less than 0.001) lower during the restitution of S2 than during S3 restitution at all DIs tested. 3) The variation of APD during the initial 100 msec of DI was significantly longer during S3 than S2 (22 +/- 5 msec versus 41 +/- 5 msec, p less than 0.001). 4) Caffeine (2 mM, n = 5) and ryanodine (10 microM, n = 5) blocked cyclic variations of tension, presumably by blocking cyclic variations of intracellular calcium ion concentrations ([Ca2+]i), and eliminated the differences in APD restitution between S2 and S3. 5) Nisoldipine at high (5 microM) but not at lower (2 microM, n = 5) concentration eliminated the differences in restitution of both APD and tension between S2 and S3. 6) BAY K 8644 (100 nM, n = 5) had no effect on this difference.

CONCLUSIONS

Greater variations of APD occur during the restitution of S3 than during S2 at short DIs. These differences appear to be caused by cyclic variations in tension and thus in [Ca2+]i. Calcium-sensitive outward currents could explain these differences in APD restitution.

Immunodetection and Identification of N-(o-Hydroxybenzylamino)Purine as a Naturally Occurring Cytokinin in Populus x canadensis Moench cv Robusta Leaves

A highly specific and sensitive enzyme-linked immunosorbent assay (ELISA) was developed for 9-beta-d-ribofuranosyl-N(6)-(o-hydroxybenzylamino)purine [(oOH)[9R]BAP] and structurally related cytokinins. As little as 3 femtomoles of the compound could be detected by this method. Cross-reactivity studies demonstrated the specificity of four polyclonal antibodies for (oOH)[9R] BAP and its free base in preference to a range of natural cytokinins and other purines. After evaluating the method by internal standardization employing [2-(3)H](oOH)[9R]BAP of high specific radioactivity as recovery marker by dilution analyses and by immunohistograms, it was possible to apply ELISA to quantify (oOH)[9R]BAP in plant extracts. In addition to (oOH)[9R]BAP, an unknown cytokinin reacting with the same antibody was detected in high performance liquid chromatography-fractionated extracts of mature Populus x canadensis Moench cv Robusta. The structure of the new compound was determined by gas chromatography-mass spectrometry and finally confirmed by synthesis as N(6)-(o-hydroxybenzylamino)purine.

Genetic variability of the murine creatine kinase B gene locus and related pseudogenes in different inbred strains of mice

The role of genetic variation in isoenzyme gene families is often poorly appreciated. We report here on the determination of DNA sequences and typing of genetic variability in four creatine kinase B (CKB) gene loci in different inbred strains of mice. The unique functional murine CKB gene was found to be nearly identical to the previously characterised rat and human sequences in both size and exon-intron structure. In this gene, approximately 0.5% allelic nucleotide positions as well as the lengths of simple A-rich and [TG]n repetitive elements located at the 5' and 3' sides of the transcribed segment, differed between inbred strains of mice. Preliminary experiments suggest that this sequence divergence is of importance for design of gene targeting strategies involving homologous DNA recombination. The three additional CKB-like gene loci in mice all had the characteristics of processed pseudogenes. By Southern blot analysis we could demonstrate that both the type and number of pseudogenes differed between inbred strains. Analysis of the CKB gene sequences enabled us to speculate about the evolutionary history of this highly polymorphic subfamily of genes.

Combination alkali/thermal burns caused by 'black liquor' in the pulp and paper industry

Three patients are presented, who sustained a unique type of burn injury while working in the pulp and paper industry in Canada. These patients suffered combination chemical (pH 11-13) and thermal (85-95 degrees C) injuries, when they were exposed to 'black liquor'--a solution which is used in the pulp and paper industry to convert wood chips to pulp. Black liquor can rapidly cause devastating thermal-corrosive burns to the skin, eyes, lungs, and upper gastrointestinal tract. One patient sustained a relatively minor, full skin thickness 3 per cent body surface area (BSA) injury to both feet and lower legs. The second patient, who was sprayed with the heated black liquor solution, sustained a full skin thickness injury to 40 per cent BSA and also suffered virtual loss of vision in one eye. The third patient, who was also sprayed with the solution, sustained a 98 per cent full skin thickness burn and severe inhalation injury, and died during day 1 postburn. Photographic documentation of all three patients is presented. The principles of treatment of this type of burn injury are reviewed. All of these burns were preventable.

Comparative investigations of the morphology and chemical composition of the eggshells of Acanthocephala. II. Palaeacanthocephala

Eggshells of the palaeacanthocephalans Acanthocephalus anguillae, Pomphorhynchus laevis and Polymorphus minutus were investigated for their fine structure as well as their chemical composition. The acanthor larvae are surrounded by four eggshells (E1-E4) separated by interstices (G1-G4). Immature eggs do not exhibit the complete set of eggshells. The chemical composition of the outermost, thin eggshell (E1) remains unknown. E2 is supplied by outer filaments of different strength; it contains keratin, which was localized electron microscopically using anti-keratin. In P. laevis and P. minutus, E3 seems to contain glycoproteins, which could not be visualized in this eggshell of A. anguillae. The innermost eggshell (E4) uniformly contains chitin. The electron-lucent interstices of the eggs of P. laevis and P. minutus are rich in polysaccharides and/or proteoglycans, whereas those of A. anguillae contain low amounts of such substances. The differences observed in the abundance of carbohydrates are discussed with respect to the life cycles of the three acanthocephalans.

Comparative investigations of the morphology and chemical composition of the eggshells of Acanthocephala. III. Eoacanthocephala

Eggshells of the eoacanthocephalans Neoechinorhynchus rutili (Neoechinorhynchidae) and Paratenuisentis ambiguus (Tenuisentidae) were investigated for their fine structure and their chemical composition. The acanthor larvae of P. ambiguus are surrounded by four eggshells (E1-E4) separated by electron-lucent interstices (G1-G4). This resembles the stratification of the eggshells of archiacanthocephalans and palaeacanthocephalans. However, an additional outer envelope (E0) exists in N. rutili. In mature eggs of this species, the broad interstice between E0 and E1 is densely packed with polysaccharides, but the other interstices also showed an intense Thiéry label. In both species, E2 along with its outer protuberances contains keratin, as does E2 in archiacanthocephalans and palaecanthocephalans, whereas E4 does not contain chitin, which contrasts with findings in the eggs of the two other classes of acanthocephalans. The results are discussed with respect to the classification of the Acanthocephala and to their transmission to the intermediate hosts.

Stereotactic localization and guidance using a machine vision technique

Machine vision techniques (video cameras) can be used to determine the three-dimensional position of objects. This transformation can be accomplished with standard mathematical algorithms. Initial accuracy tests of stereotactic localization with video cameras were performed using a standard Brown-Roberts-Wells (BRW) phantom simulator coupled with the BRW angiographic localizer. Localization accuracy was within 1.5 mm. Potential applications of machine vision techniques include freehand stereotactic localization of the position and orientation of surgical instruments. With sufficient computer speed these techniques can be used for continuous monitoring of the position of instruments within the cranial vault.

Post-mastectomy radiotherapy following adjuvant chemotherapy and autologous bone marrow transplantation for breast cancer patients with greater than or equal to 10 positive axillary lymph nodes. Cancer and Leukemia Group B

Between 2/87 and 2/91, 49 women with operable breast cancer involving greater than or equal to 10 axillary nodes were treated following mastectomy, with four cycles of Cyclophosphamide, Adriamycin, 5FU, followed by high doses of Cyclophosphamide, Cisplatin, Carmustine (HDCT) with autologous bone marrow transplant support. Forty patients received local-regional radiotherapy (generally to the chest wall, internal mammary, supraclavicular, +/- axillary nodal areas; minimum 44-50 Gy, 1.8-2 Gy/fraction, +/- 10-15 Gy scar boost; standard radiation techniques). The first nine patients did not receive local-regional radiotherapy. Three developed a local-regional failure (6-12 months after HDCT); six are without evidence of disease. Local-regional radiotherapy (LR XRT) was delivered to the subsequent 40 patients following HDCT+autologous bone marrow transplant. Six received less than 44 Gy of the planned local-regional radiotherapy due to significant toxicity and one of these failed locally. Only one local failure was observed among the 34 patients who received greater than or equal to 44 Gy. Two additional patients developed distant metastases. None of these 40 patients have failed in the axilla despite the fact that the axilla was irradiated in only 18 cases. Overall, 36/40 (90%) of these patients are without evidence of disease 4-30 months following HDCT (approximately 10-36 months after mastectomy, median 22 months). Radiotherapy was interrupted or discontinued because of progressive dyspnea, thrombocytopenia, or neutropenia in nine patients. Further studies to determine the roles of local-regional radiotherapy and HDCT in the development of these toxicities are underway. These encouraging results suggest that HDCT + autologous bone marrow transplant+local-regional radiotherapy may improve the survival rate in these high risk patients. A national randomized study to test the efficacy of this HDCT regimen is currently underway (Cancer and Leukemia Group B#9082 and Southwest Oncology Group #9114).

Relation between acute ventricular arrhythmias, ventricular late potentials and mortality in acute myocardial infarction

The relation between ventricular late potentials and the occurrence of acute (in-hospital) and hyperacute (before hospital admission) ventricular tachycardia or fibrillation was studied in 281 consecutive patients with uninterrupted acute myocardial infarction. The prevalence of late potentials was significantly higher in patients with than without ventricular tachycardia/fibrillation (65 vs 22%; p less than 0.01). These relations persisted among patients with left bundle branch block, although a different definition was used for identifying late potentials in these patients. Multivariate analysis showed that presence of late potentials and peak creatine kinase enzyme level were the only 2 independent variables associated with early ventricular tachycardia/fibrillation. Total in-hospital mortality, as well as in-hospital cardiac mortality, was significantly higher among patients with than without acute ventricular tachycardia/fibrillation. However, at 1 year, mortality rates did not differ between the 2 groups. The following conclusions were drawn from this study: (1) Late potentials are closely related to ventricular tachycardia/fibrillation in hyperacute and acute phases of infarction. (2) Presence of left bundle branch block does not mitigate against the finding of late potentials in these patients. (3) Early ventricular tachycardia/fibrillation in acute infarction is related to large infarctions and to a high in-hospital mortality rate.

Acute effects of intravenous propafenone on the internal ventricular defibrillation threshold in the anesthetized dog

In 10 treated and 2 control dogs, the short-term effects of intravenous propafenone (2 mg/kg/10 minutes, followed by 1 mg/min [n = 2] or 25 micrograms/kg/min [n = 8]) on the internal ventricular defibrillation energy requirements (DER) were investigated. Multiple stored energy levels were randomly tested and the percent successful defibrillation was plotted against the stored energy, and the raw data were fit by logistic regression. The energy at 50% (E50) and 80% (E80) defibrillation success increased after propafenone by a mean of 75% (8.4 +/- 2.4 to 14.7 +/- 5.9 joules, p less than or equal to 0.05) and 59% (11.1 +/- 3.5 to 17.6 +/- 6.7 joules, p less than or equal to 0.05), respectively. Plasma propafenone levels ranged from 778 to 2554 ng/ml (1495 +/- 592 ng/ml) at the beginning to 833 to 2193 ng/ml (1297 +/- 389 ng/ml) at the end of the defibrillation trials. Two dogs served as controls and received Ringer's solution instead of propafenone and showed the temporal stability of the preparation. In conclusion, intravenous propafenone increases the internal ventricular DER in this canine model. This may have important clinical implications in patients with automatic implantable cardioverter-defibrillators (AICDs) receiving concomitant antiarrhythmic drug therapy and in patients undergoing therapy with intravenous propafenone.

High-pressure injection injuries

High-pressure injection injuries are potentially disabling forms of trauma. Three cases are presented of patients who sustained high-pressure injuries from paint, air and water. Injuries from paint require emergency surgical débridement and exploration because of the extreme tissue toxicity of the injected material. The patient in this study had a favourable outcome after delayed closure of his wound and extensive physiotherapy. High-pressure injuries resulting from air and water can be managed conservatively, as in the two patients reported in this paper. Their treatment included tetanus prophylaxis, irrigation, dressings, splinting, admission to hospital, intravenous broad-spectrum antibiotics, radiologic assessment and careful neurovascular evaluation. Surgical débridement and exploration were not necessary.

Pathogenicity and antigenic components of excysted Giardia lamblia isolated from patients in Riyadh, Saudi Arabia

Giardia lamblia cysts were isolated from patients in Riyadh, Saudi Arabia. Cysts and trophozoites (from axenically excysted cysts) were given orally by gavage to mice to establish the pathogenicity of the Riyadh isolate. There was no effect of varying the dose of administered parasite on parasite excretion or morbidity. A typical pathologic pattern of giardiasis was demonstrated by histologic methods and electron microscopy. Antigenic components of the Riyadh isolate were compared with the Portland strain and with Entamoeba histolytica by gel diffusion immunoprecipitation and immunoblotting. There were few antigens in common between Riyadh isolate and the Portland strain, and little cross-reactivity of the Riyadh isolate with Entamoeba histolytica was observed.

A simple method for excystation of Giardia lamblia cysts

Fresh Giardia lamblia trophozoites were isolated by in vitro excystation of purified cysts from the faeces of Saudi patients. The method consisted of mixing one part of the cyst suspension with nine parts of 1 N hydrochloric acid, at pH 2, then culturing the excysted trophozoites in modified TYI-S-33 medium in sealed glass vials. During the excystation process most cysts developed a space between the trophozoite and the cyst wall, and after several steps of enlargement the trophozoite emerged at the posterior end of the cyst. Keeping the cysts at 4 degrees C for more than 10 days did not affect the excystation process. Trophozoites obtained by this method can be cryopreserved and recultured without significant loss of activity. This is a simple and rapid method of obtaining G. lamblia trophozoites from cysts in stools or from other sources.

Studies on the leishmaniases in the Sudan. 3. Clinical and parasitological studies on visceral and mucosal leishmaniasis

The epidemiological, clinical and laboratory findings of 27 patients with visceral leishmaniasis (VL) and six with mucosal leishmaniasis (ML) in Sudan are described. The diagnosis was confirmed by the demonstration of amastigotes in bone-marrow in 20 cases with VL (80%) and impression smears in 2 cases with ML. The enzyme-linked immunosorbent assay and direct agglutination test were positive in all the sera tested. The leishmanin test was positive in all patients with ML, the diameter of the reaction ranging from 18 to 28 mm (mean 23 mm). Only one isolate (from a patient with VL) grew sufficiently well in culture to be typed and this was characterized by isoenzyme electrophoresis as Leishmania donovani zymodeme LON-46. The possibility that the ML isolate could have been L. major zymodeme LON-1 is discussed. The importance of further research to isolate and identify by biochemical procedures a more representative range of isolates of Leishmania from different clinical types in the Sudan, in order to elucidate questions such as the relationship between the vectors and possible animal reservoirs, is emphasized.

Studies on the leishmaniases in the Sudan. 2. Clinical and parasitological studies on cutaneous leishmaniasis

In the Omdurman Hospital for Tropical Diseases, Sudan, from 6 October to 1 December 1986, 736 patients with cutaneous leishmaniasis (CL) were studied. The duration of the lesions varied from a few days to 4 months, usually (56%) 1-3 months. Multiple lesions ranging from one to 50 (mean = 4) were present in 80% of cases. Ulcerative lesions were found in 44%, nodulo-ulcerative in 31%, nodular in 31% and others, including infiltrated, fungating and warty lesions, in 5% of patients. The lower limbs were involved in 66%, upper limbs in 50%, face in 6%, back in 4%, chest in 2%, abdomen in 1% and buttocks in 0.1%. Lesions were also found on the ear, scalp, genitalia and mucocutaneous junctions. Lymphatic involvement was present in 11% of the patients, secondary infection in 18%, fever in 17%, pain in 38% and itching in 61%; 3% of the patients were diabetics. Features of diffuse cutaneous leishmaniasis were noted in one patient and three cases presented with an 'id' reaction. A slit-skin smear was positive in 88% of the cases. Using thin-layer starch gel electrophoresis, 23 stocks from man and one from Arvicanthis niloticus were identified by the characterization of 12 enzymes as Leishmania major zymodeme LON-1. Various therapeutic regimens are discussed. Only patients with severe lesions (approximately 15%) were given 3 to 4 weeks' treatment with intravenous Pentostam, to which all except 2 responded satisfactorily with minimal side effects.

The chemical peel

Chemical peeling of facial skin has become a valuable adjunct in the armamentarium of the facial aesthetic surgeon. Among the various techniques available, phenol solutions are the most commonly used. Peeling produces a controlled, partial-thickness chemical burn of the epidermis and the outer dermis. Several techniques are available to "fine tune" the depth of the peel. Regeneration of peeled skin results in a fresh, orderly, organized epidermis. In the dermis, a new 2- to 3-mm band of dense, compact, orderly collagen is formed between the epidermis and the underlying damaged dermis, which results in effective ablation of the fine wrinkles in the skin and a reduction of pigmentation. These clinical and histological changes are long lasting (15-20 years) and may be permanent in some patients. Because of the metabolism and systemic complications of phenol, patient selection should involve systemic evaluation of liver, renal, and cardiac function, as well as an evaluation of the skin quality and medication status of the patient. Because of potential cardiac arrhythmias, peeling must be performed in a medically supervised environment, with continuous cardiac monitoring. The local complications of peeling include pigmentation changes, scarring, milia, ectropion, infection, activation of herpes simplex, and toxic shock syndrome.

The rectus femoris myocutaneous flap for closure of difficult wounds of the abdomen, groin, and trochanteric areas

The rectus femoris myocutaneous flap has proved to be an effective means of closing particularly difficult wounds in 2 patients. One patients had a massive defect in the lower abdomen, pubic, and right groin area after the radical resection of a recurrent pleomorphic liposarcoma of the spermatic cord. The second patient presented with a huge, right greater trochanteric wound measuring 15 cm in diameter. Both patients progressed to relatively uneventful primary healing.

Toxic epidermal necrolysis: a burn-centre challenge

OBJECTIVE

To describe the clinical features and outcome of patients with toxic epidermal necrolysis.

DESIGN

Case series.

SETTING

Ross Tilley Burn Centre, Wellesley Hospital, Toronto.

PATIENTS

Ten patients (seven women) with toxic epidermal necrolysis referred to the centre from 1984 to 1990.

INTERVENTION

Biobrane (Winthrop Pharmaceuticals, New York) was applied to all raw surfaces after the epidermis had been completely separated. It was not removed until the epidermis had regenerated.

MAIN RESULTS

The age of the patients varied from 27 to 90 (mean 45) years. The proportion of body surface area involved was 20% to 95% (mean 58.5%). Nine of the patients had received steroids and antibiotics prophylactically before being referred to the burn centre; the steroids were immediately tapered and the antibiotics withdrawn unless there was a specific infection. Urinary tract infection developed in seven patients, respiratory failure in six and systemic sepsis in six. All of the patients ultimately required antibiotics for treatment of systemic infections. Two patients died; both had severe illness before the onset of the toxic epidermal necrolysis. Biobrane provided a marked reduction in pain, eliminated the need for further dressings and allowed early, aggressive physiotherapy. The wounds healed completely within 14 to 21 days, with no significant scarring or need for skin grafting.

CONCLUSIONS

The use of a temporary skin substitute is recommended for the treatment of toxic epidermal necrolysis. There is no indication for prophylactic steroid or antibiotic therapy; indeed, such therapy is probably contraindicated.

The electrical response of maize to auxins

The electrical response of Zea mays coleoptiles and suspension cultured cells to several growth-promoting auxins (IAA, IBA, 2,4-D, 2,4,5-T, 1-NAA) and some of their structural analogues (2,3-D, 2-NAA) has been tested. In coleoptile two typical electrical responses to IAA are observed: an immediated rapid depolarization, and a hyperpolarization following 7-10 minutes after the first external addition of IAA. Of the other tested compounds only 1-NAA significantly depolarized the cells, whereas all auxins as well as the analogues evoked delayed hyperpolarizations. In contrast, the suspension cells were not hyperpolarized by any of the tested compounds, but were strongly depolarized by IAA, 1-NAA, and to a lesser extent by 2-NAA. In these cells IAA and 1-NAA induced inwardly directed currents of positive charge which both saturated around 12 mA/m2. The strong pH-dependence together with the half-maximal currents 0.49 microM IAA and 0.76 microM 1-NAA point to a symport of the anions with at least 2H+. The delayed plasma membrane hyperpolarization is a different response, and seems to be initiated by the protonated auxin species. In accordance with the current literature, it is interpreted as consequence of a stimulated proton extrusion. The finding that all tested compounds evoked a hyperpolarization, makes this response unspecific. It is concluded that a stimulation of proton extrusion is a necessary, but not sufficient step to induce elongation growth.

Public pensions in transition: an optimal policy path

"The main purpose of this paper is to analyze problems of financing an old-age insurance when birth rates are low and population declines or fertility fluctuates with time....[The author] investigates a theoretical model which analyzes the welfare optimal combination of private savings via the capital market and the state forced savings via a PAYG [pay-as-you-go] financed public pension system. Long-run effects as well as short-run implications are considered. The economic properties of an optimal steady state are determined and additionally an optimal transition path--the best feasible conversion policy--which leads to the new steady state is specified."

The chemotherapy of rodent malaria. XLVI. Reversal of mefloquine resistance in rodent Plasmodium

Multiple drug resistance in Plasmodium falciparum is already showing evidence of extending to mefloquine, which at present is one of the few alternative antimalarials for the prevention or treatment of infection with such parasites. Neither verapamil nor cyproheptadine, which reverse chloroquine (CQ) resistance in P. falciparum and in rodent malaria parasites, reverse resistance to mefloquine (MEF) in the MEF-resistant NS/1100 line of P. yoelii ssp. NS. On the other hand, such resistance is clearly reversed when mefloquine is administered to infected mice together with penfluridol.

'Special effects' burn injuries

Three patients are presented with significant flame burns, resulting from accidents occurring during 'special effects' situations in the entertainment industry. These occurred as a result of the spontaneous combustion of various materials, during events in live theatre (gun powder), a television commercial (artificial 'rocket fuel'), and a video presentation (magnesium oxide). All three patients sustained flash burns to the face and hands. One patient sustained a significant bilateral corneal injury, a gamekeeper's thumb, and a permanent continuous right-sided high frequency tinnitus, in addition to his burn injury. Photographic documentation of all three patients is presented. The total loss of time from work for all patients was 6 months. All these injuries were potentially preventable.