Towards standardisation of surface electromyography measurements in the horse: Bipolar electrode location.

The use of surface electromyography in the field of animal locomotion has increased considerably over the past decade. However, no consensus exists on the methodology for data collection in horses. This study aimed to start the development of recommendations for bipolar electrode locations to collect surface electromyographic data from horses during dynamic tasks. Data were collected from 21 superficial muscles of three horses during trot on a treadmill using linear electrode arrays. The data were assessed both quantitatively (signal-to-noise ratio (SNR) and coefficient of variation (CoV)) and qualitatively (presence of crosstalk and activation patterns) to compare and select electrode locations for each muscle. For most muscles and horses, the highest SNR values were detected near or cranial/proximal to the central region of the muscle. Concerning the CoV, there were larger differences between muscles and horses than within muscles. Qualitatively, crosstalk was suspected to be present in the signals of twelve muscles but not in all locations in the arrays. With this study, a first attempt is made to develop recommendations for bipolar electrode locations for muscle activity measurements during dynamic contractions in horses. The results may help to improve the reliability and reproducibility of study results in equine biomechanics.

Neurological soft signs as an endophenotype in an African schizophrenia population - a pilot study.

OBJECTIVE: The use of endophenotypes, such as neurological soft signs (NSS), is advocated as one possible method to elucidate the heterogeneity of schizophrenia. Exploring the associations between NSS and specific illness symptoms has revealed some trends, although results have been conflicting. To date, such studies have been conducted largely on Caucasian populations and our pilot study represents the first attempt to gather such data in a homogenous African population. METHOD: Fifty-one patients, all of Xhosa ethnicity and participating in a larger schizophrenia genetic study were recruited. NSS were evaluated using a modified Neurological Evaluation Scale. Data were analysed using SPSS with the strength of the overall relationships between NES groups and SANS and SAPS components analyzed by means of canonical correlation analysis. RESULTS: The canonical correlation of SANS domains (excluding asociality) with the NES conceptual groups was 0.53 (SE=0.11, p=0.024) and of the SAPS domains 0.38 (SE=0.13, p=0.943). CONCLUSION: Our results suggest a correlation between negative symptoms of schizophrenia and the presence of NSS, supporting the recruitment of a larger sample to more comprehensively evaluate a possible role for NSS as an endophenotype in the Xhosa schizophrenia population. Taking into account that NSS evaluations allow for inexpensive, relatively easy-to-do objective evaluations, this method presents us with a valuable research tool that can be used effectively within our under-resourced environment to help inform on the neurobiological substrate of schizophrenia.

Polymorphism and mesomorphism of oligomeric surfactants: effect of the degree of oligomerization.

A series of cationic oligomeric surfactants (quaternary dodecyldimethylammonium ions with two, three, or four chains connected by an ethylene spacer at the headgroup level, abbreviated as dimer, trimer, and tetramer) were synthesized and characterized. The influence of the degree of oligomerization on their polymorphic and mesomorphic properties was investigated by means of X-ray diffraction, polarizing optical microscopy, thermogravimetry, and differential scanning calorimetry. All compounds display layered arrangements with interdigitated dodecyl chains. The increase in the degree of oligomerization increases the interlayer distance and decreases the ordering in the solid phase; whereas the dimer sample is fully crystalline with well-developed 3D ordering and the trimer and tetramer crystallize as highly ordered crystal smectic phases. The number of thermal phase transitions and sequence of phases are markedly affected by the number of dodecyl chains. Anhydrous samples exhibit polymorphism and thermotropic mesomorphism of the smectic type, with the exception of the tetramer that displays only transitions at higher temperature associated with decomposition and melting. All hydrated compounds form lyotropic mesophases showing reversible phase transitions upon heating and cooling. The sequence of liquid-crystalline phases for the dimer, typical of concentrated ionic surfactant systems, comprises a hexagonal phase at lower temperatures and a smectic phase at higher temperatures. In contrast, the trimer and tetramer reveal textures of the hexagonal phase.

Structural and thermal study of mesomorphic dodecylammonium carrageenates.

Structural characteristics and thermal stability of a series of dodecylammonium carrageenates formed by stoichiometric complexation of dodecylammonium chloride and differently charged carrageenans (kappa-, iota- and lambda-carrageenan, respectively) were investigated. IR spectral analysis confirmed the electrostatic and hydrogen bond interactions between the dodecylammonium and carrageenan species. X-ray diffraction experiments show increased ordering in the complexes compared to that in the parent carrageenans. Dodecylammonium carrageenates have a layer structure, in which a polar sublayer contains layers of carrageenan chains and a nonpolar sublayer consists of conformationally disordered dodecylammonium chains electrostatically attached to the carrageenan backbone. The major factor that determines the dodecylammonium carrageenate structure is cationic surfactant, while the carrageenans moiety plays a major role in determining thermal properties.

Abortion care training framework for nurses within the context of higher education in the Western Cape.

The high morbidity and mortality rate due to illegal abortions in South Africa necessitated the implementation of abortion legislation in February 1997. Abortion legislation stipulates that registered nurses who had undergone the proposed abortion care training--certified nurses--may carry out abortions within the first 12 weeks of pregnancy. Currently it seems that an inadequate number of nurses are being trained in the Western Cape to provide pregnant women with counselling, to perform abortions and/or refer problem cases. No real attempts have since been made by higher education institutions in the Western Cape to offer abortion care training for nurses. This case study explores the situation of certified nurses and the context in which they provide abortion care in different regions of the Western Cape. The sampling included a random, stratified (non-proportional) number of designated state health care facilities in the Western Cape, a non-probability purposive sampling of nurses who provided abortion care, a non-probability convenience sample of women who had received abortion care, and a non-probability purposive sampling of final-year pre-registration nursing students. Data was generated by means of questionnaires, a checklist and semi-structured interviews. The main findings of this study indicate that the necessary infrastructure required for legal abortion is in place. However, the ongoing shortage of trained health care practitioners hampers abortion care services. Deficiencies were identified in the existing provincial protocol as some of the guidelines were either not in use or had become obsolete. Certified midwives who had been trained by the regional offices of the Department of Health: Western Cape were skilled in carrying out the abortion procedure, but other aspects of abortion care mainly carried out by other categories of nurses required more attention. This article suggests a training framework that should provide focus for the development of a formal programme or programmes for the training of nurses in abortion care at higher education institutions in the Western Cape.

Interactions in mixed cationic surfactants and dextran sulfate aqueous solutions.

The interactions between a hydrophilic anionic polysaccharide, dextran sulfate, and oppositely charged surfactants, n-alkylammonium chlorides (the number of carbon atoms per chain being 10, 12, and 14), were investigated by optical microscopy, X-ray diffraction, microelectrophoretic mobility, conductivity, surface tension, and light-scattering measurements at 303 K. The increase of surfactant alkyl chain length shifts both the critical aggregation (cac) and the critical micelle concentrations (cmc) toward lower surfactant concentration. Light-scattering and microelectrophoretic data revealed the coexistence of differently structured complexes beyond the cac. The presence of giant vesicles indicates that at least one type of species is ordered in bilayers. X-ray analysis of dry n-alkylammonium dextran sulfates exhibited mesomorphous ordering and interplanar spacings typical for lamellar structures; i.e., n-alkylammonium molecules form more or less disordered bilayers interconnected with dextran sulfate chains, thus forming multilamellar stacks. The average basic lamellar thickness increased linearly with the increase of surfactant chain length, whereas the average number of lamellar bilayers in the stack of lamellae decreases.

Synergistic effects of low doses of histatin 5 and its analogues on amphotericin B anti-mycotic activity.

The increase in the use of antifungal agents for prophylaxis and therapy has led to the development of antifungal drug resistance. Drug combinations may prevent or delay resistance development. The aim of the present study was to investigate whether naturally and designed cationic antifungal peptides act synergistically with commonly used antimycotics. No enhanced activity was found upon addition of dhvar4, a designed analogue of the human salivary peptide histatin 5, or PGLa to fluconazole or 5-flucytosine, respectively. In contrast, strong synergism of amphotericin B with the peptides was found against several Aspergillus, Candida, and Cryptococcus strains, and against an amphotericin B-resistant C. albicans laboratory mutant in the standardised broth microdilution assays according to the NCCLS standard method M27-T. Amphotericin B showed synergism with dhvar5, another designed analogue of histatin 5, and with magainin 2 against all seven tested strains. Combinations of amphotericin B with histatin 5, dhvar4, and PGLa showed synergism against four of the seven strains. The growth inhibitory activity of amphotericin B was enhanced by sub-MIC concentrations of peptide, but its haemolytic activity remained unaffected, suggesting that its cytotoxicity to host cells was not increased and that peptides may be suitable candidates for combination therapy.

Nutritional status of patients in a long-stay hospital for people with mental handicap.

OBJECTIVE: To investigate the general nutritional status of patients in Alexandra Hospital, Cape Town, and to determine whether dietary copper deficiency was causing anaemia in hospital patients. DESIGN: Descriptive and cross-sectional analytical studies. SETTING: A long-stay hospital for people with mental handicap. SUBJECTS: Information was obtained from the total hospital population. In addition, groups of 15 patients were selected from each of two specific wards, one with active and the other inactive patients. To determine whether copper deficiency was causing anaemia, a sample of 30 patients, divided into three groups (a hypochromic microcytic, a normochromic anaemic and a non-anaemic group) was studied. MAIN OUTCOME MEASURES: Body mass indices (BMI) and daily dietary intakes were compared with Recommended Daily Allowance (RDA) values. Serum copper and serum caeruloplasmin levels were used to detect possible copper deficiency. RESULTS: A considerable number of patients were found to be underweight (32% of males and 26% of females had BMIs < 20). A smaller number were obese (6% of males and 17% of females had BMIs > 30). Poor nutrition was more common in severely handicapped patients and those with acquired causes of their mental handicap. Subjects with Down syndrome were generally well nourished and occasionally obese. Poor dietary intakes of biotin, pantothenic acid, vitamin D and copper were encountered. The serum copper and caeruloplasmin values were found to be within normal limits. Patients with hypochromic, microcytic anaemia had higher serum copper and caeruloplasmin levels than those with normochromic anaemia and the control group. CONCLUSIONS: A number of nutritional problems among the inpatient population were found. Many were undernourished, while a smaller number of patients were overweight. In both the active and inactive wards macronutrient intakes were generally within normal limits. However, some micronutrient nutritional deficiencies were encountered. We were unable to establish that dietary copper deficiency was the cause of anaemia in our patients. Elevated serum copper and caeruloplasmin levels found in hypochromic, microcytic patients were thought to result from the existence of low-grade infection, associated with elevation of the acute-phase protein, caeruloplasmin.

Amphotericin B- and fluconazole-resistant Candida spp., Aspergillus fumigatus, and other newly emerging pathogenic fungi are susceptible to basic antifungal peptides.

The present study shows that a number of basic antifungal peptides, including human salivary histatin 5, a designed histatin analog designated dhvar4, and a peptide from frog skin, PGLa, are active against amphotericin B-resistant Candida albicans, Candida krusei, and Aspergillus fumigatus strains and against a fluconazole-resistant Candida glabrata isolate.

Phase variation in Helicobacter pylori lipopolysaccharide.

Helicobacter pylori NCTC 11637 lipopolysaccharide (LPS) expresses the human blood group antigen Lewis x (Le(x)) in a polymeric form. Le(x) is beta-D-galactose-(1-4)-[alpha-L-fucose-(1-3)]-beta-D-acetylglucosamine. Schematically the LPS structure is (Le(x))n-core-lipid A. In this report, we show that Le(x) expression is not a stable trait but that LPS displays a high frequency (0.2 to 0.5%) of phase variation, resulting in the presence of several LPS variants in one bacterial cell population. One type of phase variation implied the loss of alpha1,3-linked fucose, resulting in variants that expressed nonsubstituted polylactosamines (also called the i antigen), i.e., Le(x) minus fucose; LPS: (lactosamine)n-core-lipid A. The switch of Le(x) to i antigen was reversible. A second group of variants arose by loss of polymeric main chain which resulted in expression of monomeric Le(y); LPS: (Le(y))-core-lipid A. A third group of variants arose by acquisition of alpha1,2-linked fucose which hence expressed Le(x) plus Le(y); LPS: (Le(y))(Le(x))n-core-lipid A. The second and third group of variants switched back to the parental phenotype [(Le(x))-core-lipid A] in lower frequencies. Part of the variation can be ascribed to altered expression levels of glycosyltransferase levels as assessed by assaying the activities of galactosyl-, fucosyl-, and N-acetylglucosaminyltransferases. Clearly phase variation increases the heterogeneity of H. pylori, and this process may be involved in generating the very closely related yet genetically slightly different strains that have been isolated from one patient.

Synthetic histatin analogues with broad-spectrum antimicrobial activity.

Histatins are salivary histidine-rich cationic peptides, ranging from 7 to 38 amino acid residues in length, that exert a potent killing effect in vitro on Candida albicans. Starting from the C-terminal fungicidal domain of histatin 5 (residues 11-24, called dh-5) a number of substitution analogues were chemically synthesized to study the effect of amphipathicity of the peptide in helix conformation on candidacidal activity. Single substitutions in dh-5 at several positions did not have any effect on fungicidal activity. However, multi-site substituted analogues (dhvar1 and dhvar2) exhibited a 6-fold increased activity over dh-5. In addition, dhvar1 and dhvar2 inhibited the growth of the second most common yeast found in clinical isolates, Torulopsis glabrata, of oral- and non-oral pathogens such as Prevotella intermedia and Streptococcus mutans, and of a methicillin-resistant Staphylococcus aureus. In their broad-spectrum activity, dhvar1 and dhvar2 were comparable to magainins (PGLa and magainin 2), antimicrobial peptides of amphibian origin. Both the fungicidal and the haemolytic activities of dhvar1, dhvar2 and magainins increased at decreasing ionic strength.

Typing of Helicobacter pylori with monoclonal antibodies against Lewis antigens in lipopolysaccharide.

Recently, it has been shown that the lipopolysaccharide (LPS) O antigen of Helicobacter pylori contains Lewis x (Lex), Lewis y (Ley), or both Lex and Ley antigens. We applied a serotyping method for H. pylori by an enzyme-linked immunosorbent assay with monoclonal antibodies (MAbs) specific for these antigens and the related fucosylated H type 1 (H1) antigen. The selected MAbs recognized the Lex and/or Ley structures in the LPS of H. pylori. The agreement between the results of biochemical compositional analysis and the serological data validated our serotyping system. A total of 152 strains from different geographic origins (The Netherlands, Canada, Poland, Italy, and People's Republic of China) were examined for typeability based on the presence of Lewis antigens. One hundred twenty-nine (84.9%) strains were typeable, and 12 different serotyping patterns were observed; 80.9% of the strains contained Lex and/or Le(y) antigens, and 18.4% reacted with the MAb against the related H1 antigen either alone or in combination with the Lex and/or Ley antigen. Our results show that the Lex and Ley antigens are frequently encountered in the LPS of H. pylori strains from various geographic origins. This typing method is an easy-to-perform technique, which can be used for strain differentiation in epidemiological studies of H. pylori infections.

Potential role of molecular mimicry between Helicobacter pylori lipopolysaccharide and host Lewis blood group antigens in autoimmunity.

Helicobacter pylori is involved in gastritis, gastric and duodenal ulcers, gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. Earlier studies already suggested a role for autoimmune phenomena in H. pylori-linked disease. We now report that lipopolysaccharides (LPS) of H. pylori express Lewis y, Lewis x, and H type I blood group structures similar to those commonly occurring in gastric mucosa. Immunization of mice and rabbits with H. pylori cells or purified LPS induced an anti-Lewis x or y or anti-H type I response, yielding antibodies that bound human and murine gastric glandular tissue, granulocytes, adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma cells. Experimental oral infections in mice or natural infection in humans yielded anti-Lewis antibodies also. The beta chain of gastric (H+,K+)-ATPase, the parietal cell proton pump involved in acid secretion, contained Lewis y epitopes; gastric mucin contained Lewis x and y antigenic determinants. Growth in mice of a hybridoma that secretes H. pylori-induced anti-Lewis y monoclonal antibodies resulted in histopathological evidence of gastritis, which indicates a direct pathogenic role for anti-Lewis antibodies. In conclusion, our observations demonstrate that molecular mimicry between H. pylori LPS and the host, based on Lewis antigens, and provide understanding of an autoimmune mechanism for H. pylori-associated type B gastritis.

[Prevalence of HIV antibodies in pregnant women in the Amsterdam HIV reference station research, 1988-1993]. / Prevalentie van HIV-antistoffen bij zwangere vrouwen in het Amsterdamse HIV-peilstationonderzoek, 1988-1993.

Pregnant women were asked to undergo a HIV test in two hospitals, one maternity clinic (n = 12.784; 1988-1993) and one abortion clinic (n = 2089; 1990-1993) in Amsterdam, in order to establish trends in HIV prevalence. Participation rates were 92.4% and 84.4%, respectively. Among pregnant women the overall HIV prevalence was 0.27% (0.04% for pregnant women without a known HIV risk and 2.6% for women with a known HIV risk) and in the abortion clinic the overall HIV prevalence was 0.91%. The HIV prevalence over the years remained fairly constant. In the most recent years a slight rise was noticed in the HIV prevalence in the group pregnant women with a known HIV risk caused by an increase in the number of women from AIDS endemic countries in this group.

A comparison of pefloxacin/metronidazole and doxycycline/metronidazole in the treatment of laparoscopically confirmed acute pelvic inflammatory disease.

A double-blind, randomised study was conducted to compare the efficacy and safety of a combination of pefloxacin and metronidazole versus doxycycline and metronidazole in patients with pelvic inflammatory disease (PID). The clinical diagnosis had to be confirmed by laparoscopy before patients were included. Of the 74 patients who fulfilled the clinical criteria for PID, laparoscopy confirmed the diagnosis in only 40 patients (54%). The microorganism most frequently found as causative pathogen was Chlamydia trachomatis. Both treatment groups showed a good response to the study-medication. At discharge 9 patients in the pefloxacin group (45%) were cured and 10 patients (50%) had improved. In the doxycycline group 7 patients (35%) were cured and 10 patients (50%) had improved. Obviously pefloxacin/metronidazole and doxycycline/metronidazole are equally effective in the treatment of PID.

A randomized clinical trial comparing two methods of fascia closure following midline laparotomy.

Three hundred forty women undergoing midline laparotomy were randomized into an interrupted suture (polyglactin 910, size 1) or a continuous suture (polyglyconate, size 0) closure group. The two groups were well balanced with respect to various risk factors for postoperative wound complications. Early evaluation revealed no differences between the continuous and interrupted suture groups with respect to wound infection (3% vs 1%), superficial wound dehiscence (2% vs 4%), and deep wound dehiscence (0.6% vs 0%). Late evaluation showed no differences between the two groups either. Continuous polyglyconate and interrupted polyglactin 910 sutures had a similar incidence of suture fistula (0% vs 2%), wound pain (1% vs 2%), and incisional hernia (3% vs 4%). Continuous closure was done faster and resulted in less foreign-body suture material. Despite its smaller diameter, the polyglyconate suture also retains a higher tensile strength after surgery than does the quicker-degrading polyglactin 910 suture. Results of this study lead to the conclusion that a running polyglyconate suture is the better choice for closure of the abdominal-wall fascia following midline laparotomy.

Tissue reaction to suture materials revisited: is there argument to change our views?

Tissue reactivity to ten different suture materials (silk, plain catgut, chrome catgut, tevdek, ticron, ethibond, vicryl, dexon, maxon and prolene) was evaluated on the basis of conventional microscopic assessment of eight histologic parameters at 7 days following surgery in the rat. Each suture material was placed at different localizations in the abdominal facial layer of 6 rats, thus a total of 60 rats were operated on. A completely standardized and reproducible system of microscopic assessment was used. Weighed discriminant sum values of these parameters showed no systematic differences between tissue reaction to these sutures. The computed addition of all possible magnitudes of weighing factors to the tissue reactivity parameters did not change this negative result. Discriminant analysis showed that it is unlikely that conventional histologic parameters of tissue reaction constitute a single concept like 'tissue reactivity'. It is concluded that at 7 days after surgery the effect of surgical trauma still nullifies the possible differences between suture materials with respect to tissue reaction. Minimizing surgical trauma should, therefore, be reappraised as more important for physiologic wound healing than the use of biocompatible sutures.

Tissue reaction and surgical knots: the effect of suture size, knot configuration, and knot volume.

Tissue reaction surrounding surgical knots was assessed histologically using a semiquantitative scoring system in 40 male Wistar rats. We tested sizes 2/0 and 4/0 (United States Pharmacopeia [USP]) coated polyglycolic acid and coated polyglactin-910 sutures, and two different knots. In addition, we measured the volume of the different knots and the total volume of tissue reaction surrounding the knots. Multivariate analysis showed only suture material and suture size to be independent factors determining tissue reaction. An increase of suture size resulted in a more than four- to sixfold increase in knot volume and a more than two- to threefold increase in the amount of the tissue-reaction sheath; however, the addition of extra throws to the knot enlarged the knot body by a factor of ony 1.5 and the tissue-reaction sheath by a factor of 1.0-1.9. These findings suggest that the use of thick-gauge suture material adds much more to the total amount of foreign body and tissue reaction in the wound than the addition of extra throws to the knot and might, therefore, be deleterious to optimum wound healing.

Piperacillin for prophylaxis in gynecological surgery.

The effectiveness of perioperative Piperacillin for prevention of operative-site infection after gynaecological surgery was studied in a total of 100 patients. In an open randomized clinical trial of 52 women undergoing abdominal or vaginal hysterectomy Piperacillin was compared to the combination Gentamicin/Metronidazole. Piperacillin was well-tolerated. Surgical-site infection was diagnosed in the Piperacillin group in two patients and in the Gentamicin/Metronidazole group in one patient. The occurrence of postoperative febrile morbidity was also similar between the two group. In 48 patients undergoing complicated gynecological surgery of long duration, only Piperacillin was administered perioperatively. Thirty-five of these 48 women underwent oncological operations and the mean operative length was 3.3 h. One patient developed a transient rash after the administration of Piperacillin. No other adverse side-effects were observed. Nine of these 48 patients developed a surgical-site infection postoperatively, and this was found to be significantly more often than in the first group of 52 patients. It was concluded that Piperacillin seems to be a valuable alternative for perioperative prophylaxis in gynecological surgery. Its effectiveness in vaginal and abdominal hysterectomy is similar to the combination of Gentamicin/Metronidazole, but after complicated surgery of long duration a decreased effectiveness should be reckoned with.