Detecting quantitative trait loci affecting beef tenderness on bovine chromosome 7 near calpastatin and lysyl oxidase

From a study of 3 large half-sib families of cattle, we describe linkage between DNA polymorphisms on bovine chromosome 7 and meat tenderness. Quantitative trait loci (QTL) for Longissimus lumborum peak force (LLPF) and Semitendonosis adhesion (STADH) were located to this map of DNA markers, which includes the calpastatin (CAST) and lysyl oxidase (LOX) genes. The LLPF QTL has a maximum lodscore of 4.9 and allele substitution of approximately 0.80 of a phenotypic standard deviation, and the peak is located over the CAST gene. The STADH QTL has a maximum lodscore of 3.5 and an allele substitution of approximately 0.37 of a phenotypic standard deviation, and the peak is located over the LOX gene. This suggests 2 separate likelihood peaks on the chromosome. Further analyses of meat tenderness measures in the Longissimus lumborum, LLPF and LL compression (LLC), in which outlier individuals or kill groups are removed, demonstrate large shifts in the location of LLPF QTL, as well as confirming that there are indeed 2 QTL on bovine chromosome 7. We found that both QTL are reflected in both LLPF and LLC measurements, suggesting that both these components of tenderness, myofibrillar and connective tissue, are detected by both measurements in this muscle.

Mapping and pyramiding of qualitative and quantitative resistance to stripe rust in barley

The identification and location of sources of genetic resistance to plant diseases are important contributions to the development of resistant varieties. The combination of different sources and types of resistance in the same genotype should assist in the development of durably resistant varieties. Using a doubled haploid (DH), mapping population of barley, we mapped a qualitative resistance gene ( Rpsx) to barley stripe rust in the accession CI10587 (PI 243183) to the long arm of chromosome 1(7H). We combined the Rpsx gene, through a series of crosses, with three mapped and validated barley stripe rust resistance QTL alleles located on chromosomes 4(4H) (QTL4), 5(1H) (QTL5), and 7(5H) (QTL7). Three different barley DH populations were developed from these crosses, two combining Rpsx with QTL4 and QTL7, and the third combining Rpsx with QTL5. Disease severity testing in four environments and QTL mapping analyses confirmed the effects and locations of Rpsx, QTL4, and QTL5, thereby validating the original estimates of QTL location and effect. QTL alleles on chromosomes 4(4H) and 5(1H) were effective in decreasing disease severity in the absence of the resistance allele at Rpsx. Quantitative resistance effects were mainly additive, although magnitude interactions were detected. Our results indicate that combining qualitative and quantitative resistance in the same genotype is feasible. However, the durability of such resistance pyramids will require challenge from virulent isolates, which currently are not reported in North America.

Drink and drug driving: what's the skipper up to?

OBJECTIVE

Since the introduction of random breath testing (RBT) in Australia there has been a significant reduction in drink driving, as measured by alcohol-related crashes. In contrast, the prevalence of drug-related road fatalities is on the increase. One strategy that targets drink- and/or drug-driving is the promotion of a designated driver or 'skipper'. This paper determines to what extent the 'skipper' is driving alcohol or drug-free.

METHODS

A convenience sample of university students from The University of Western Australia completed a questionnaire that included questions on drug and alcohol use while driving as the designated 'skipper'.

RESULTS

The mean age of the 286 participants was 21 years. Among the students who reported acting as the designated 'skipper' during the past 12 months, 26% of the students drove, as the designated 'skipper,' while feeling the effects of alcohol. Similarly, 18% of students who reported using drugs drove, as the 'skipper', while feeling the effects of the drug. Multivariate analysis identified that the presence of random drug testing would act as a deterrent for drug driving while the designated 'skipper'.

CONCLUSION

Although three-quarters of designated 'skippers' do not drink and/or drug drive, a sizeable proportion of young drivers continue to place themselves and, more importantly, their passengers and the entire community at an elevated risk of injury.

IMPLICATIONS

Campaigns that target the responsibility of the 'skipper' and that are included as part of drink-driving campaigns would be beneficial. It is premature to be making recommendations on random drug testing for drivers.

The nursing outcomes classification: its relevance to school nursing

Two surveys were conducted to determine school nurses' perceptions of the relevance of 190 outcomes developed by the Nursing Outcomes Classification (NOC) research team to school nursing practice. First, a national random survey of members of the National Association of School Nurses was conducted. Participants were asked to identify the percentage of children and families for whom school nurses affect health outcomes. Usable responses were returned from 227 school nurses (22% response rate). Ninety outcomes were perceived as relevant for 30% or more of children and families; 8 outcomes were perceived as relevant for 50% or more of children and families. A second survey--targeting state representatives attending a school nursing leadership meeting--was conducted using a revised version of the instrument. The legend was changed to degree of relevance to school nursing practice, with a response scale of 0 to 10. Usable responses were returned from 31 state representatives (41% response rate). The means of 172 of 190 outcomes were above 5 (median point on the 10-point scale of relevance). The findings of both surveys indicate that a large number of NOC outcomes are useful for documentation of the effectiveness of nursing interventions in school settings.

Genetic control of susceptibility to UV-induced immunosuppression by interacting quantitative trait loci

Ultraviolet B radiation (290-320 nm) initiates a dose and wavelength dependent down-regulation of cell-mediated immunity which is critical in experimental ultraviolet radiation (UV) carcinogenesis, preventing immune attack on highly antigenic UV-induced tumors. UV-induced immunosuppression has been demonstrated in humans and may be a risk factor for skin cancer. In this study, we have investigated genetic linkage of the autosomal loci controlling this trait. Previously, we had derived a model describing control of susceptibility to UV-induced immunosuppression in inbred mice by unlinked interacting autosomal and X-linked loci. A genome-wide scan using MIT microsatellite markers was carried out on 100 backcross (BALB/c x (BALB/c x C57BL/6) F1) mice derived from the inbred strains BALB/c (low susceptibility) and C57BL/6 (high susceptibility) and tested for systemic UV-induced immunosuppression of a contact hypersensitivity response. The values for % suppression for each animal and the genotype data were used to investigate genetic linkage by multiple regression analysis. Significance was assessed using the permutation test. Both main effects and interactive effects were investigated, first with each genotype marker singly, and secondly, in a novel approach using markers pairwise. A joint model was derived in which all loci and pairs of loci identified were included simultaneously in a multiple regression model. This model indicates four quantitative trait loci (QTLs) with significant main effects, one on chromosome 10 which decreased susceptibility to UV-induced immunosuppression and QTLs on chromosomes 6, 17 and 1 which increased susceptibility. Additionally, loci on chromosomes 14 and 19 showed significant interaction with the locus on chromosome 1. Further investigation indicated a potential three-way interaction involving the loci on chromosomes 1, 14 and 19.

Laryngeal swabs for diagnosing tuberculosis

The value of smear and culture of laryngeal swabs as a method of confirming pulmonary tuberculosis was investigated in Indian children. A total of 116 children with 'suspected' tuberculosis had a Mantoux test and chest X-ray. Of these, 51 had a positive Mantoux and/or chest X-ray compatible with tuberculosis, and this group had two laryngeal swabs taken on each of 3 consecutive days. The Mantoux test was positive in 37 (73%) of the 51 'probable' cases. Chest X-ray was abnormal in 36 (71%) cases and compatible with tuberculosis in 20 (39.7%). Mycobacterium tuberculosis was cultured from laryngeal swabs in 14 (28%) children and in another three children smears were positive but culture-negative. The overall confirmation rate for tuberculosis was 33%. Laryngeal swabs are a simple method of confirming tuberculosis and may be undertaken in out-patients.

Platelet function in dogs treated for lymphoma and hemangiosarcoma and supplemented with dietary n-3 fatty acids

A prospective randomized, double-blind clinical trial was performed to test the hypothesis that dogs with malignancies that are supplemented with n-3 fatty acids do not have clinical or laboratory evidence of coagulation disorders or altered platelet function when compared with unsupplemented dogs with similar malignancies. Thirteen dogs with hemangiosarcoma and 66 dogs with lymphoma were evaluated. Coagulation status of the dogs with lymphoma and hemangiosarcoma was evaluated with prothrombin time, partial thromboplastin time, platelet count, and in vitro platelet aggregometry using the whole-blood method. These tests were performed at 5 time points: before beginning the diet (week 0), at weeks 3, 15, and 21, and at 1 year or when progressive disease was evident. Alterations in platelet function in dogs receiving a diet supplemented with dietary n-3 fatty acids were not identified when compared to dogs fed a control diet. Dietary n-3 fatty acid supplementation using this dosage and ratio in dogs with lymphoma or hemangiosarcoma did not induce clinically significant hemorrhage in these animals. Therefore, supplementation with n-3 fatty acids did not result in clinical or laboratory evidence relating to uncontrolled hemorrhage in these dogs.

GIGANTEA: a circadian clock-controlled gene that regulates photoperiodic flowering in Arabidopsis and encodes a protein with several possible membrane-spanning domains

Flowering of Arabidopsis is promoted by long days and delayed by short days. Mutations in the GIGANTEA (GI) gene delay flowering under long days but have little or no effect under short days. We have now isolated the GI gene and show that it encodes a novel, putative membrane protein. By comparing the sequence of the Arabidopsis gene with that of a likely rice orthologue and by sequencing mutant alleles, we identify regions of the GI protein that are likely to be important for its function. We show that GI expression is regulated by the circadian clock with a peak in transcript levels 8-10 h after dawn. The timing, height and duration of this peak are influenced by daylength. We analysed the interactions between GI and the LHY, CCA1 and ELF3 genes, previously shown to affect daylength responses; we show that the rhythmic pattern of GI expression is altered in the elf3, CCA1-OX and lhy genotypes, and that CCA1 and LHY expression are reduced by gi mutations. Our results are consistent with the idea that GI plays an important role in regulating the expression of flowering time genes during the promotion of flowering by photoperiod.

National survey to identify the nursing interventions used in school settings

A national survey of members of the National Association of School Nurses was conducted to identify interventions from the Nursing Interventions Classification (NIC) that are used by school nurses. Usable responses were returned from 522 school nurses. The findings were that 163 interventions were used, on the average, from every day to once a year, and all but three interventions were used by one or more respondents. Certain interventions were significantly associated with special education or grade level of children served by nurses. It is concluded that the NIC is a useful tool to standardize documentation for school nursing.

Comparison of the effects of asparaginase administered subcutaneously versus intramuscularly for treatment of multicentric lymphoma in dogs receiving doxorubicin

OBJECTIVE

To determine the effectiveness and safety of asparaginase administered s.c. versus i.m. for treatment of multicentric lymphoma in dogs receiving doxorubicin.

DESIGN

Prospective study.

ANIMALS

49 dogs with multicentric lymphoma.

PROCEDURE

Dogs were treated with doxorubicin every 3 weeks, for a total of 5 treatments, and were given 3 weekly treatments of asparaginase, s.c. or i.m. Using high-performance liquid chromatography, mean plasma asparagine, aspartic acid, glutamine, and glutamic acid concentrations were determined in dogs before and during treatment with asparaginase (10,000 U/m2 of body surface area, once a week for 3 weeks). Asparaginase was administered s.c. in 23 dogs and i.m. in 26 dogs. Variables evaluated included time to response to chemotherapy, remission and survival times, and clinical and serum biochemical indicators of toxicoses.

RESULTS

Using the World Health Organization's staging system for lymphoma, 30 dogs were in clinical stage III and 19 were in clinical stage IV. One week after asparaginase treatment, plasma asparagine concentrations were low and plasma aspartic acid, glutamine, and glutamic acid concentrations were high. Differences in plasma amino acid concentrations were not found between s.c. and i.m. groups. For dogs in clinical stage IV, i.m. administration of asparaginase significantly decreased the number of days to complete remission, compared with s.c. administration (8 vs 17 days, respectively). For dogs in clinical stage III, i.m. administration favorably increased the duration of first remission (191 vs 103 days) and survival time (289 vs 209 days). Overall, dogs treated i.m. had a faster response to chemotherapy (9 vs 15 days), a longer remission (191 vs 109 days), and a longer survival time (286 vs 198 days), compared with all dogs treated s.c. Asparaginase toxicoses were not observed regardless of the route of administration.

CLINICAL IMPLICATIONS

For dogs with multicentric lymphoma that are receiving doxorubicin, i.m. treatment with asparaginase is more effective than s.c. treatment.

Constitutive properties of adult mammalian cardiac muscle cells

BACKGROUND

The purpose of this study was to determine whether changes in the constitutive properties of the cardiac muscle cell play a causative role in the development of diastolic dysfunction.

METHODS AND RESULTS

Cardiocytes from normal and pressure-hypertrophied cats were embedded in an agarose gel, placed on a stretching device, and subjected to a change in stress (sigma), and resultant changes in cell strain (epsilon) were measured. These measurements were used to examine the passive elastic spring, viscous damping, and myofilament activation. The passive elastic spring was assessed in protocol A by increasing the sigma on the agarose gel at a constant rate to define the cardiocyte sigma-versus-epsilon relationship. Viscous damping was assessed in protocol B from the loop area between the cardiocyte sigma-versus-epsilon relationship during an increase and then a decrease in sigma. In both protocols, myofilament activation was minimized by a reduction in [Ca2+]i. Myofilament activation effects were assessed in protocol C by defining cardiocyte sigma versus epsilon during an increase in sigma with physiological [Ca2+]i. In protocol A, the cardiocyte sigma-versus-epsilon relationship was similar in normal and hypertrophied cells. In protocol B, the loop area was greater in hypertrophied than normal cardiocytes. In protocol C, the sigma-versus-epsilon relation in hypertrophied cardiocytes was shifted to the left compared with normal cells.

CONCLUSIONS

Changes in viscous damping and myofilament activation in combination may cause pressure-hypertrophied cardiocytes to resist changes in shape during diastole and contribute to diastolic dysfunction.

Gel stretch method: a new method to measure constitutive properties of cardiac muscle cells

Diastolic dysfunction is an important cause of congestive heart failure; however, the basic mechanisms causing diastolic congestive heart failure are not fully understood, especially the role of the cardiac muscle cell, or cardiocyte, in this process. Before the role of the cardiocyte in this pathophysiology can be defined, methods for measuring cardiocyte constitutive properties must be developed and validated. Thus this study was designed to evaluate a new method to characterize cardiocyte constitutive properties, the gel stretch method. Cardiocytes were isolated enzymatically from normal feline hearts and embedded in a 2% agarose gel containing HEPES-Krebs buffer and laminin. This gel was cast in a shape that allowed it to be placed in a stretching device. The ends of the gel were held between a movable roller and fixed plates that acted as mandibles. Distance between the right and left mandibles was increased using a stepper motor system. The force applied to the gel was measured by a force transducer. The resultant cardiocyte strain was determined by imaging the cells with a microscope, capturing the images with a CCD camera, and measuring cardiocyte and sarcomere length changes. Cardiocyte stress was characterized with a finite-element method. These measurements of cardiocyte stress and strain were used to determine cardiocyte stiffness. Two variables affecting cardiocyte stiffness were measured, the passive elastic spring and viscous damping. The passive spring was assessed by increasing the force on the gel at 1 g/min, modeling the resultant stress vs. strain relationship as an exponential [sigma = A/k(ekepsilon - 1)]. In normal cardiocytes, A = 23.0 kN/m2 and k = 16. Viscous damping was assessed by examining the loop area between the stress vs. strain relationship during 1 g/min increases and decreases in force. Normal cardiocytes had a finite loop area = 1.39 kN/m2, indicating the presence of viscous damping. Thus the gel stretch method provided accurate measurements of cardiocyte constitutive properties. These measurements have allowed the first quantitative assessment of passive elastic spring properties and viscous damping in normal mammalian cardiocytes.

Structure-function relationships in interphotoreceptor retinoid-binding protein (IRBP)

PURPOSE

Interphotoreceptor retinoid binding protein (IRBP) binds hydrophobic ligands in the retina. The polypeptide consists of 1230 amino acids in four 300 amino acid long repeats. We asked whether each of the four repeats can bind one retinoid or fatty acid analog. Our rationale was to make protein variants from the human cDNA bearing one or more of the repeats and examine binding capacities and dissociation constants.

METHODS

Proteins were characterized by SDS-PAGE, western blotting, N-terminal sequencing, and CD spectroscopy. Binding properties with all-trans-retinol and 16-anthryloxy-palmitic acid (16-AP) were characterized by ligand fluorescence enhancement and curve fitting.

RESULTS

Binding capacities varied according to the length of each protein. Each repeat possesses the capability of binding retinol and 16-AP.

CONCLUSIONS

The data contrast with the idea that two or more repeats are needed to bind one molecule of ligand. Each repeat binds a retinoid and fatty acid analog, suggesting that each has multiple ligand binding sites or one binding site with affinity for different ligands. Last, these data fit well with the current model of multiple binding sites in IRBP derived from quadruplication of an ancestral monomeric binding protein.

Relevance of NANDA and health promotion diagnoses to school nursing. National Association of School Nurses

This is a report of a national survey of 490 members of the National Association of School Nurses which described the relevance of 109 nursing diagnoses approved by NANDA (1992) and 29 health promotion (wellness) diagnoses developed by the authors. The relevance of these 138 nursing diagnoses for school nursing was determined by the percent of participants who checked "Yes" for the diagnostic categories they observed in their practice and for which they provided one or more interventions. More than half of the sample checked "Yes" for 67 NANDA diagnoses; health promotion diagnoses were checked "Yes" by 45% to 89% of the sample. The implications are that NANDA and health promotion diagnoses are relevant to school nursing and could readily be incorporated into practice to facilitate data collection that supports both the funding of school nurses and program development for children, families, and school staff.

Polarization asymmetry in waves backscattering from highly absorbant random media

Within the range in which light penetration depth is approximately the same as or less than the diameter of the particles in the medium, particulate media with considerable absorption behave as two-dimensional, rough-surface structures. As penetration depth increases, a complicated transition between volume and surface effects is seen. For these media, low-order scattering sequences have small spatial extent, making observation of polarization characteristics difficult. We present an experimental technique to access the low-order scattered photons by artificially reinjecting them through total internal reflections. Using a dielectric layer in contact with the high-absorption medium, we are able to observe fourfold polarization asymmetry in backscattering from highly absorbant media. We discuss the origin of the polarization patterns in a ray-optics approximation and suggest possibilities for solving practical problems encountered in characterizing composites with appreciable absorption.

Consistency and validity of patient administered assessment of quality of life by the MOS SF-36; its association with disease activity and damage in patients with systemic lupus erythematosus

OBJECTIVE

To investigate the metric properties and validity of the assessment of quality of life by the MOS Short Form 36 (SF-36) in patients with systemic lupus erythematosus (SLE) and to examine the effect of disease on quality of life.

METHODS

Cross sectional study of 150 patients with SLE (age: mean 39.7 yrs, SD 11.4 yrs; 95% female) attending 2 specialist lupus clinics between November 1994 and April 1995. Shortly before or after the consultation patients completed the SF-36 and the MOS SF-20 with an additional question about fatigue (SF-20+) in random order. Disease activity was measured by the British Isles Lupus Activity Group System (BILAG), disease damage by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) damage index (SLICC).

RESULTS

SF-36 domains were shown to be internally consistent (Cronbach's coefficient alpha > or = 0.71). Significant associations of the SF-36 domains with the corresponding domains of the SF-20+ and with global disease activity measured by BILAG were observed. SF-36 scores in patients with SLE were significantly lower than in controls. Different disease activity levels were significantly associated with different quality of life scores, with excellent ability to record the continuum from good health to serious illness by the SF-36. Disease activity had greater effect on quality of life than age, cumulative damage, or disease duration.

CONCLUSION

This study shows the SF-36 is internally consistent and proves construct, discriminatory, and criterion validity for the SF-36 and construct validity for the SF-20+ in patients with SLE. The SF-36 is preferred because of its broader scope of questions, its widespread use, and previous international validation for a wide variety of diseases.

The effect of suture type on meniscus repair. A clinical analysis

To test the hypothesis that use of permanent suture for meniscus repair allows longer, more stable fixation and more complete healing than absorbable suture, 89 patients (90 meniscus repairs) undergoing repair between 1990 and 1993 were evaluated. Eight patients were lost to follow-up, leaving 81 patients with 82 meniscal repairs. All patients underwent meniscus repair with either absorbable or permanent suture and were re-evaluated at an average of 24.1 months follow-up. The tears were within 5 mm of the peripheral meniscal rim and communicated with the peripheral blood supply (either red-red or red-white zone). Group 1 (absorbable suture) was comprised of 50 patients (38 males and 12 females; 19 right and 31 left knees). There were 36 medial and 14 lateral repairs. Group 2 (permanent suture) was comprised of 31 patients with 32 meniscus repairs (23 males and 8 females; 17 right knees and 14 left knees). There were 23 medial and 9 lateral meniscus repairs. Follow-up consisted of objective (clinical examination, range of motion, McMurray test, detectable swelling, locking, and joint-line tenderness) and subjective evaluations (15 question series of visual analog scales). Success or failure of the meniscal repair was based on the degree of symptoms present at follow-up. Group 1 had 9 failures, while Group 2 had none. All of the failures were rescoped and required additional surgical procedures. Group 1 had higher scores on all subjective questions. Data were analyzed using the two-sample t-test and the chi-squared test. The absolute failure rate was statistically significant. In this study, menisci repaired with permanent sutures had a lower incidence of clinical symptoms and a much lower failure rate. Thus, permanent suture is recommended for meniscus repair as it appears to allow for longer and more stable fixation, permitting more complete maturation and remodeling of the meniscus.

Object recognition from point-light stimuli: evidence of covariation structures in conceptual representation

Current theories of concepts and categorization involve easily identifiable attributes or features as the basic informational fodder of representation, and some composite of such features as the conceptual representation. This 'standard model' is now being questioned on a number of empirical and theoretical grounds, especially those concerning the informational origins of features. In this paper we examine the evocation of conceptual functions by point-light stimuli in which objects and constituent features are not directly given at all, but have to be constructed and construed in some way. We have maintained in previous studies that conceptual representation depends upon nested covariation hierarchies, and here suggest that the evocativeness of point-light stimuli can be explained by the structured covariation information they present. In two studies we found evidence that variation in the overall amount and the structure of covariation information in point-light stimuli is associated with variation in a number of conceptual response functions, such as the recognizability of objects from the stimuli, and the dispersion of responses. We take these results as evidence that conceptual representation depends upon, and features and other constituents are generated 'on-line' from, nested covariation hierarchies.

Motility mutants of Vibrio cholerae O1 have reduced adherence in vitro to human small intestinal epithelial cells as demonstrated by ELISA

Vibrio cholerae must colonize the human small intestine to cause diarrhoeal disease. V.cholerae strains N16961 (EI Tor, Inaba) and 395 (classical, Ogawa) adhered to the epithelial cell surface and the mucus layer of isolated human small intestinal epithelial cells. They adhered specifically to the mucosa and apical membrane in thin sections of small intestine. No binding to the basolateral membrane of dissected epithelial tissue or to intracellular components of the epithelial cells was observed by either light or indirect immunofluorescence microscopy. Based on these results, a modified ELISA was developed to quantitatively study adherence of V. cholerae to human small intestinal epithelial cells. The assay used homogenized human small intestinal mucosal tissue as the substrate for binding. Treatment of the epithelial cell homogenate with 2-mercaptoethanol to disrupt protein and glycoprotein secondary structure inhibited the binding of V. cholerae strains, suggesting that binding was to specific receptors. Several V. cholerae strains and mutants from both biotypes were tested for adherence in the modified ELISA. Wild-type strains of both biotypes and non-enterotoxigenic strains, which were known to colonize humans, adhered. V. cholerae mutants defective in motility, flagellar structure of chemotaxis, which were known to exhibit reduced colonization in animal models, exhibited decreased adherence. The specificity of the assay and its ability to quantify binding should facilitate identification and the study of adherence factors involved in the colonization of human small intestinal epithelial cells by V. cholerae.

Analogical reasoning and the nature of context: a research note

Recent theorising about children's reasoning has tended to move towards a 'contextualist' view of cognition and away from the idea of an overall, context-free, mechanism, varying in efficiency, which is the presupposition underlying traditional standardised reasoning tests. An earlier study suggesting improved reasoning performance among children on socio-cognitively meaningful versions of Raven's Matrices tended to support this shift. The main purpose of the study reported here was to observe whether a similar improvement would be found with contextually-based analogical reasoning problems as well. Ten analogy items from a standardised test were administered to 11-year-olds together with 10 structurally-equivalent knowledge-based items. The results reflected improved performance on the latter, overall, and additional analyses led to further suggestions about the nature of the 'contextual advantage' and the origins of item difficulty.

Nitric oxide production by lymphatic endothelial cells in vitro

The present study demonstrates that confluent monolayer cultures of lymphatic endothelial cells produce and secrete NO. Immunofluorescent studies showed that eNOS activity can be stimulated with Ca ionophore to enhance the production of NO. Cells exposed to LPS and various cytokines stimulated the production of iNOS which showed the greatest increase in activity at 4 hrs and declined at 18 and 24 hrs. These studies provide evidence that, within the lymphatic vascular lumen, nitric oxide may be produced by the lymphatic endothelium which interact with various vasoactive substances to regulate lymphatic vascular tone. In addition, the production of NO by LEC may be important in the regulation of lymphatic vascular tone in order to more readily accommodate sudden fluctuations in lymph flow and pressure that normally occur during the process of lymph formation and propulsion.

Fractionated radioimmunotherapy of human colon carcinoma xenografts with 131I-labeled monoclonal antibody CC49

Radiolabeled monoclonal antibodies (MoAbs) have been used for radioimmunotherapy (RIT) of human colon cancer xenografts in an attempt to develop promising clinical approaches to improving therapy success. Several strategies have been investigated to accomplish this task while decreasing toxicity. The CC49 antibody was selected for the present studies because of its relatively high affinity constant (16.2 x 10(9) M-1) for the high molecular weight TAG-72 mucinous antigen secreted by human colon cancer cells. In previous studies, when CC49 was labeled with 131I, it demonstrated a substantial therapeutic advantage over the lower affinity antibody (B72.3) reactive with TAG-72. One of the chief problems in achieving cures with RIT is that hematological toxicity limits the quantity of radionuclide that can be administered. In other studies of dose fractionation using athymic nude mice and 131I-labeled intact MoAbs reactive with human colon cancer xenografts, multiple administrations at approximately 1-week intervals were found to produce more prolonged tumor growth inhibition and less toxicity than single administrations. The purpose of this study was to investigate the therapeutic efficacy and toxicity of 131I-labeled CC49 MoAb administered with short fractionation schedules against human colon cancer xenografts to determine the optimal treatment schedule, with the ultimate aim of applying this approach in clinical trials. The results reported here demonstrate that in an animal colon cancer xenograft model, RIT delivered in a fractionated schedule clearly presents a therapeutic advantage. For example, one administration of 600 microCi 131I-labeled CC49 to LS174T tumor-bearing mice was lethal to approximately 25% of mice but produced no tumor regressions. Fractionation of this dose to two administrations of 300 microCi 131I-labeled CC49 at a 3-day interval resulted in tumor regression in approximately 30% of the animals, accompanied by a similar 25% death rate. The administration of 300 microCi 131I-labeled CC49 at a 7-day interval resulted in 15% animal lethality, but no complete tumor regressions. When three administrations of 300 microCi 131I-labeled CC49 were given over a 1-week period on days 0, 3, and 7, tumor regressions occurred in approximately 40% of the animals, accompanied by a 30% death rate. Moreover, three administrations of 300 microCi 131I-labeled CC49 resulted in 20% tumor recurrence, whereas two administrations of 131I-labeled CC49 resulted in 60% tumor recurrence.(ABSTRACT TRUNCATED AT 400 WORDS)

Novel antagonists of platelet-activating factor. 1. Synthesis and structure-activity relationships of benzodiazepine and benzazepine derivatives of 2-methyl-1-phenylimidazo[4,5-c]pyridine

Following the discovery of moderately potent antagonist activity platelet-activating factor (PAF) in 2-methyl-1-phenylimidazo[4,5-c]pyridine (2) (IC50 = 840 nM), 19 derivatives (3-21) were prepared which incorporated various lipophilic groups attached to the phenyl 4-position. Structure-activity relationships were evaluated where PAF antagonist activity was measured in vitro by determining the concentration of compound (IC50) required to inhibit the PAF-induced aggregation of rabbit washed platelets and in vivo by determining the oral dose (ED50) which protected mice from a lethal injection of PAF. [1,5]Benzodiazepines, e.g., 14 (2,3-dihydro-1-methyl-4-[4-(2-methylimidazo[4,5-c] pyrid-1-yl)phenyl]-1H-[1,5]benzodiazepin-2-one) (IC50 = 4.9 nM, Ed50 = 0.03 mg/kg po), were found to possess equivalent or superior potency to the 1,4-dihydropyridine PAF antagonist UK-74,505 (1,4-(2-chlorophenyl)-1,4-dihydro-3-(ethoxycarbonyl)-6-methyl-2- [4-(2-methylimidazo[4,5-c]pyrid-1-yl)phenyl]-5-[N-(2-pyridyl) carbamoyl]pyridine) in vitro and in vivo. Furthermore, a potent benzazepine, 21 (7,8-dichloro-1-methyl-4-[4-(methylimidazo[4,5-c]pyrid-1-yl) phenyl]-2,3,4,5-tetrahydro-1H-1-benzazepin-2-one) (IC50 = 0.5 nM, ED50 = 0.03 mg/kg po), was discovered. These investigations prompted the synthesis and evaluation of additional diazepine derivatives, which are described in the following paper. The relationship between the key PAF antagonist pharmacophores of 2-methyl-1-phenylimidazo[4,5-c]pyridine, a triazolothienodiazepine (WEB2170), and a pyrrolothiazolidine (RP-52,770) is discussed.

Mutagenesis of the BC1 and BV1 genes of African cassava mosaic virus identifies conserved amino acids that are essential for spread

The products of three open reading frames encoded by the bipartite geminiviruses have been implicated in viral spread: AC2, BV1 and BC1. Alignment of the DNA B encoded gene products, BV1 and BC1, from African cassava mosaic virus (ACMV) with six other bipartite geminiviruses showed several highly conserved regions. Specific amino acids were selected for mutagenic studies to ascertain the tolerance of the virus to change and to identify the regions within these two proteins required for normal functioning. Various mutant DNA B constructs, and a wild-type construct, were inoculated onto three host plant species with an equivalent DNA A construct. Three of the mutant constructs were infectious on Nicotiana benthamiana and N. clevelandii, but only two induced ACMV disease symptoms on N. tabacum cv. Samsun. Sequencing of the viral DNA extracted from the sap of systemically infected plants confirmed the maintenance of introduced base changes. The amino acid at position 95 on the BV1 gene product was identified as non-essential for normal functioning of the protein. The alteration of the amino acid at position 145 in BC1 demonstrated the ability of the virus to tolerate a conservative change. The lack of tolerance to other changes in amino acids has given an indication of the importance of maintaining protein structure for these proteins to function normally.

Regeneration of transgenic plants from the commercial apple cultivar Royal Gala

A transformation system was developed for the commercial apple (Malus X domestica Borkh.) cultivar Royal Gala. Leaf pieces from in vitro-grown shoots were cocultivated for 2 days with Agrobacterium tumefaciens strain LBA4404 containing the binary vectors pKIWI105 or pKIWI110. Shoots were produced on a shooting medium containing kanamycin (50 mg·L(-1)). A 2-day incubation period on kanamycin-free medium prior to antibiotic selection enhanced the regeneration of kanamycin-resistant shoots. The majority of the kanamycin-resistant shoots also expressed GUS (β-glucuronidase) activity. The putatively transformed shoots were rooted on a medium containing kanamycin (50 mg·L(-1)). Rooted plants were established in a greenhouse, and plants transformed with pKIWI110, which contains a mutant Arabidopsis acetolactate synthase gene, were shown to be resistant to the herbicide Glean(™). Integration of T-DNA into the apple genome was confirmed by PCR and Southern hybridization analyses.

T-Fix endoscopic meniscal repair: technique and approach to different types of tears

Endoscopic meniscus repair using the T-Fix suture device (Acufex Microsurgical, Inc, Mansfield, MA) allows ease of suture placement for meniscus stability without the problems associated with ancillary incisions such as neurovascular compromise. It is ideal for the central posterior horn tears that are difficult using conventional techniques. Vertical tears, bucket handle tears, flap tears, and horizontal tears can be approached using a temporary "anchor stitch" to stabilize the meniscus before T-Fix repair. The basic method of repair and our approach to these different types of tears is presented.

Software trapping: a strategy for finding genes in large genomic regions

We present an approach to the gene identification phase of positional cloning that combines sparse sampling of DNA sequences from large genomic regions with computational analysis. We call the method "software trapping." The goal is to find coding exons while avoiding massive DNA sequence determination and contig assembly. Instead, rapid sequence sampling is combined with exon screening software such as a newly developed package called XPOUND to identify coding sequences. We have tested the approach using a set of model genomic sequences with known intron/exon structures as well as with bona fide P1 genomic clones. The results suggest that the strategy is a useful complement to other methods for finding genes in poorly characterized regions of genomes.

Release of sialyltransferases from rat liver Golgi membranes by a cathepsin D-like proteinase: comparison of the release of Gal beta 1-4GlcNAc alpha 2-6 sialyltransferase, Gal beta 1-3(4)GlcNAc alpha 2-3 sialyltransferase and lactosylceramide alpha 2-3 sialyltransferase (SAT-1)

The activities of Gal beta 1-3(4)GlcNAc alpha 2-3 sialyltransferase and SAT-1 were measured in rat liver Golgi in inflammation; both enzymes decreased by about 50%. This compares with increases of about 3-fold for the Gal beta 1-4GlcNAc alpha 2-6 sialyltransferase. All three sialyltransferases were released from disrupted Golgi membranes by incubation at reduced pH which activates an endogenous cathepsin D which is believed to be the lysosomal enzyme. Pepstatin A was found to block the release of all three sialyltransferases providing support for the role of cathepsin D as the proteinase that clips the catalytic portions of the enzymes from their membrane anchor and stem regions.

Developing standards for patient information. Highlights that effective communication can improve health care delivery

Presents a review of the patient information literature used in the Taunton and Somerset NHS Trust. Describes the changes made to this literature in an attempt to improve the patient experience of the health care delivery. Highlights that appropriate, timely and effective communication with patients can improve the effectiveness of care and the efficiency with which it is delivered.

Systemic cytokine measurements: their role in monitoring the response to therapy in patients with rheumatoid arthritis

OBJECTIVE

To determine the value of serial measurements of circulating cytokines in patients with rheumatoid arthritis in response to the introduction of disease modifying anti-rheumatic drugs (DMARDs).

METHODS

A prospective 12-week study of 98 patients starting second line therapy with serial measurements of IL1 beta, IL2 receptor, IL6, TNF, and urinary neopterins as well as ESR, CRP and rheumatoid factor.

RESULTS

The markers of the acute phase response fell significantly with treatment as did the rheumatoid factor. IL-6 fell in certain sub-groups (significantly so after sulphasalazine SZP) of treated patients, but no other consistent change in circulating cytokine levels was demonstrated. Urinary neopterins rose with therapy.

CONCLUSIONS

The measurement of circulating cytokine levels in patients with rheumatoid arthritis is of limited benefit; macrophage function (as measured by urinary neopterins) is initially enhanced by DMARDs in patients with rheumatoid arthritis.

Regulation of distal esophageal mucosal blood flow: the roles of nitric oxide and substance P

BACKGROUND

An increase in esophageal mucosal blood flow (MBF) may be an important protective mechanism against mucosal injury from noxious agents that are ingested or refluxed. This study investigated the changes in MBF and the regulation thereof after intraluminal application of noxious chemical stimuli. The role, if any, of substance P (SP) and nitric oxide (NO), two potent vasodilatory substances, and the vascular distribution of SP in the distal esophagus were evaluated.

METHODS

Esophageal MBF was measured in anesthetized dogs with a laser Doppler flow probe attached to manometry and pH probes. MBF was measured before and after topical application of HCl (2 ml; 1N) or capsaicin (2 ml; 0.5%) in the distal esophagus. The effects on MBF of intraarterial SP and bradykinin were also determined. Pharmacologic antagonists and denervation procedures were used to delineate the mechanisms that regulate MBF.

RESULTS

Sequential luminal applications of hydrochloric acid (HCl) or a single application of capsaicin increased MBF (p < 0.01). Topical intraluminal lidocaine blocked the response to capsaicin (p > 0.2) but not to HCl (p < 0.05). Abrupt increases in MBF occurred with intraarterial SP or bradykinin (p < 0.01). Neither atropine nor truncal vagotomy blocked the increase in MBF from these peptides or noxious stimuli. The NO synthesis antagonist NG-nitro-L-arginine methyl ester (L-NAME) blocked the response to bradykinin and attenuated the response to HCl (p < 0.05). NG-nitro-L-arginine methyl ester did not affect the response to SP or capsaicin. A substance P antagonist blocked the effects of both capsaicin (p > 0.6) and SP (p > 0.1) but not that of HCl (p < 0.01) or bradykinin (p > 0.01).

CONCLUSIONS

Intraluminal applications of HCl or capsaicin appear to stimulate increases in esophageal MBF by different mechanisms. HCl produces an adaptive response that appears dependent on the paracrine effect of NO. Capsaicin-sensitive neurons mediate vasodilation through SP neurotransmission, independent of extrinsic vagal or cholinergic innervation.

The effect of bed rest and intra-articular steroids on the acute phase response in rheumatoid arthritis

The impact of therapeutic interventions on the disease process in patients with rheumatoid arthritis (RA) is complex. The effect on the acute phase response was studied in 25 in-patients on imposed bed rest, who were randomised to treatment with (n = 12) or without (n = 13) intra-articular steroids. C-reactive protein (CRP), ESR and IgA alpha-1 antitrypsin complex levels were measured on admission and on days 3 and 5. Levels at onset were not different between groups. At day 3 and day 5, a significant (p < 0.001) fall in CRP was seen only in the intra-articular steroid group. Other cytokine and disease parameter measures did not alter during the study period (although IL-6 and CRP correlated at onset in all 25 patients). The mean duration of the hospital stay was longer for the patients treated with bed rest only. Thus, bed rest when combined with intra-articular steroids produced a rapid systemic effect, while bed-rest alone did not have an effect on the acute phase response over this short time scale.

Sister chromatid exchanges in peripheral lymphocytes in newborns treated with phototherapy and vitamin E

A study was undertaken to determine whether blue fluorescent light might affect the sister chromatid exchange (SCE) frequency of peripheral lymphocytes in icteric newborns undergoing continuous phototherapy treatment (72 h). Also, the potential preventive effect of vitamin E on SCE frequency was studied in a subgroup of 11 preterm and 9 fullterm newborns after daily administration of vitamin E (46.44 mumol/kg/d, im). The results revealed that only the preterm icteric newborns showed an increase in mean SCE frequency of peripheral lymphocytes after phototherapy (9%, p = 0.02), but in no case did the highest SCEs/cell ratio exceed the normal values. No correlation was found between the average SCE rate and birth weight, gestational age or bilirubin levels. Also, no difference in SCEs was observed between newborns treated or untreated with vitamin E.

Angiotensin II receptor binding associated with nigrostriatal dopaminergic neurons in human basal ganglia

In the human brain, receptor binding sites for angiotensin are found in the striatum and in the substantia nigra pars compacta overlying dopamine-containing cell bodies. In contrast, angiotensin-converting enzyme occurs in the substantia nigra pars reticulata and is enriched in the striosomes of the striatum. In this study, using quantitative in vitro autoradiography, we demonstrate decreased angiotensin receptor binding in the substantia nigra and striatum of postmortem brains from patients with Parkinson's disease. In the same brains the density of binding to angiotensin-converting enzyme shows no consistent change. We propose, from these results, that angiotensin receptors in the striatum are located presynaptically on dopaminergic terminals projecting from the substantia nigra. In contrast, the results support previous studies in rats demonstrating that angiotensin-converting enzyme is associated with striatal neurons projecting to the substantia nigra pars reticulata. These findings raise the possibility that newly emerging drugs that interact with the angiotensin system, particularly converting enzyme inhibitors and new nonpeptide angiotensin receptor blockers, may modulate the brain dopamine system.

1,4-Dihydropyridines as antagonists of platelet activating factor. 1. Synthesis and structure-activity relationships of 2-(4-heterocyclyl)phenyl derivatives

A novel class of 2-(4-heterocyclylphenyl)-1,4-dihydropyridines (2-38) possessing antagonist activity against platelet activating factor (PAF) was prepared by the Hantzsch synthesis from a variety of ethyl 4'-heterocyclic-substituted benzoylacetates, aryl or heteroaryl aldehydes, and substituted 3-aminocrotonamides or 3-aminocrotonate esters. Structure-activity relationships were evaluated where PAF antagonist activity was measured in vitro by determining the concentration of compound (IC50) required to inhibit the PAF-induced aggregation of rabbit washed platelets, and in vivo by determining the oral dose (ED50) which protected mice from a lethal injection of PAF. The nature of the substituent at the dihydropyridine 2-position was found to be important for both in vitro and in vivo activity, whereas there was greater flexibility for structural variation at the 4- and 5-positions. The most potent compound was 4-(2-chlorophenyl)-1,4-dihydro-3-(ethoxycarbonyl)-6-methyl-2-[4-(2- methylimidazo[4,5-c]pyrid-1-yl)phenyl]-5-[N-(2- pyridyl)carbamoyl]pyridine (17, UK-74,505), IC50 = 4.3 nM, ED50 = 0.26 mg/kg po, which was found to be approximately 33 times more potent in vitro (rabbit platelet aggregation) and about 8 times more potent in vivo (murine lethality) than WEB2086. Compound 17 also exhibited a long duration of action in the dog (inhibition of PAF-induced whole blood aggregation ex vivo was maintained for greater than 24 h following a single oral dose of 75 micrograms/kg) and was highly selective as a PAF antagonist, showing only weak affinity (IC50 = 6600 nM) for the [3H]nitrendipine binding site. As a result of its high oral potency, selectivity, and duration of action, UK-74,505 has been selected for clinical evaluation.

Regulation of the activities of African cassava mosaic virus promoters by the AC1, AC2, and AC3 gene products

DNA fragments comprising each of the promoter regions from the geminivirus African cassava mosaic virus (ACMV) were cloned into the pUC18-based vector, pG1, producing transcriptional fusions with the beta-glucuronidase gene (GUS) and nopaline synthase terminator sequence. The relative activity of each promoter construct was analyzed by a GUS expression assay of extracts from Nicotiana clevelandii protoplasts coelectroporated with the GUS reporter constructs and constructs in which individual ACMV open reading frames (ORFs) were placed under control of a cauliflower mosaic virus 35 S promoter. Results suggest repression of the AC1 gene by its gene product, which is required for ACMV DNA synthesis. The promoter activity observed for the single promoter for the DNA A genes encoding functions of spread and the regulation of replication (AC2 and AC3 ORFs) was unaffected by coelectroporation with any of the ACMV ORF constructs. Promoters for the AV1 (coat protein) gene and the two DNA B genes (BV1 and BC1) were activated by electroporation of the AC2 ORF construct. To a lesser extent promoters for the AV1 and BV1 genes were activated with the AC3 ORF construct. The same pattern of promoter repression and activation was observed when transgenic N. benthamiana plants expressing the GUS reporter constructions were inoculated with ACMV DNA A.

Analysis of the potential promoter sequences of African cassava mosaic virus by transient expression of the beta-glucuronidase gene

DNA fragments from promoter regions of the geminivirus, African cassava mosaic virus, were cloned into pG1, a vector based on pUC18, producing transcriptional fusions with the beta-glucuronidase (GUS) gene and nopaline synthase termination sequence. The activity of each promoter construct was assessed by analysing the transient expression of GUS in Nicotiana clevelandii protoplasts. The results demonstrated that constructs containing the common region of DNA A showed much stronger promoter activity in the complementary sense than in the viral sense. These results were supported by the analysis of promoter activity in transgenic N. benthamiana plants. In comparison, in protoplasts a region upstream of the AC2 open reading frame was shown to have moderate promoter activity. Unlike DNA A, the complementary sense DNA B promoter constructs had weak activity; the viral sense DNA B promoter constructs appeared to be regulated by host factors. The implications of these results for the regulation of early and late genes are discussed.

Urinary IL-6: a marker for mesangial proliferative glomerulonephritis?

A prospective study of plasma and urinary interleukin-6 (IL-6) levels was performed in 54 patients undergoing renal biopsy to determine whether detectable urinary IL-6 was a reliable marker for mesangial proliferation. Interleukin-6 was found in both the urine and plasma of seven patients, the urine alone of 15 patients, and the plasma alone of two patients. Interleukin-6 was not detected in the urine or the plasma of the remaining 30 patients, the urine of 10 healthy controls or the urine of 10 patients with rheumatoid arthritis with raised plasma IL-6. Interleukin-6 was found in the urine of only one out of an additional seven patients with lupus nephritis. Urinary IL-6 was associated with a variety of renal abnormalities and was not restricted to those with mesangial hypercellularity. Furthermore, many patients with mesangial hypercellularity did not have detectable urinary IL-6. There was no correlation between urinary IL-6 and plasma IL-6, urinary albumin excretion or urinary creatinine. These results suggest that IL-6 detected in the urine is a marker of renal IL-6 production, but not specifically of mesangial hypercellularity. The patients with IL-6 in the urine had a mean serum creatinine significantly higher than those without IL-6. It is not possible to distinguish at present whether IL-6 contributes to renal dysfunction or whether it reflects renal damage.

Roles of motility and flagellar structure in pathogenicity of Vibrio cholerae: analysis of motility mutants in three animal models

Wild-type Vibrio cholerae of both El Tor and classical biotypes (strains N16961 and 395, respectively) and nonmotile mutant derivatives with and without flagellar structures were characterized in three different animal models: (i) the rabbit ileal loop, (ii) the removable intestinal tie adult rabbit diarrhea (RITARD) model, and (iii) the suckling mouse model. Both the wild-type strains and nonmotile mutants were toxinogenic in the rabbit ileal loop and the suckling mouse models. However, all of the nonmotile mutants produced significantly less fluid accumulation than did the wild-type parental strains. The two nonmotile mutants of strain N16961 did not adhere to rabbit ileal mucosa, but both nonmotile mutants derived from strain 395 exhibited adherence. In the RITARD model, the motile El Tor strains were more virulent than both the flagellate and aflagellate nonmotile mutants (all infected rabbits died within 18 h), while the nonmotile mutants, when fatalities occurred, required 78 to 105 h to produce a fatal outcome. Likewise, the motile classical parent 395 produced a fatal outcome within ca. 25 h, while nonmotile mutants required 69 to 96 h. The nonmotile flagellate strain KR31 was not significantly more virulent than the nonmotile aflagellate strain KR26. Of the two classical nonmotile mutants, KR1, which produces a coreless sheathlike structure, was clearly more virulent (5 of 10 rabbits died within 96 h), while KR3 (nonmotile, aflagellate) did not produce fatalities in any of the 10 rabbits tested. Similarly, no significant difference in diarrheagenicity or colonizing ability was detected between the two nonmotile mutants derived from the El Tor strain, but the classical nonmotile mutant with the coreless sheath caused significantly greater diarrhea and colonized for a longer time than did the isogenic nonmotile aflagellate strain, KR3. No significant differences between the nonmotile mutants were detected in competition studies done with suckling mice. Analysis of the wild-type and mutant strains in these three animal models clearly demonstrated a role for motility in V. cholerae pathogenicity, while analysis of only the nonmotile mutants derived from the classical parent suggested a role for flagellar structures.

Mutagenesis of the AC3 open reading frame of African cassava mosaic virus DNA A reduces DNA B replication and ameliorates disease symptoms

Small insertions were made independently at each of four unique restriction sites on African cassava mosaic virus (ACMV) DNA A to disrupt the three overlapping complementary-sense open reading frames (ORFs) herein designated AC1, AC2 and AC3. The DNA A mutants were assayed for their infectivity by agroinoculation of monomeric constructs to Nicotiana benthamiana plants containing chromosomal insertions of ACMV DNA B. Disruption of the AC3 ORF alone resulted in a delay and amelioration of disease symptoms which correlated with reduced replication of DNA B. Normal replication of DNA A still carrying the AC3 ORF mutation was found in extracts from these plants. No ACMV DNA or symptoms were observed in corresponding inoculations with either the simultaneous disruption of the overlapping AC2 and AC3 ORFs or disruption of the AC1 ORF. Complementation by the inoculation of different mutant pairs produced a delay in disease symptoms followed by repair of mutated sites. A DNA A construct with the virus-sense AV1 (coat protein) ORF deleted was infectious producing typical ACMV disease symptoms. A similar construct with a larger deletion encompassing the complementary-sense AC3 ORF produced symptomless infections. The DNA recovered from plants revealed DNA A of normal size where the position of the deleted ORF was replaced with cloning vector DNA. Significantly reduced DNA B replication was observed for the AC3 deletion construct.

Autoradiographic localization of angiotensin-converting enzyme and angiotensin II binding sites in early atheroma-like lesions in rabbit arteries

1. Early atheroma-like lesions in rabbits are associated with increased sensitivity to serotonin. The localization and distribution of angiotensin-converting enzyme (ACE) and angiotensin II (AII) binding sites has been studied in these developing lesions by quantitative in vitro autoradiography. 2. In sham-operated control vessels, ACE was localized predominantly to intimal and adventitial sites, whereas in lesioned arteries the level of ACE detected in these regions was significantly reduced. 3. In control vessels AII receptor binding was distributed largely in the outer media, whereas in lesioned vessels AII receptor binding was dispersed throughout the media with the highest levels of binding in the outer media. 4. There was a significant amount of binding associated with ACE and with AII receptors in the extra-adventitial inflammatory tissue of lesioned arteries. 5. Apparent loss of ACE from intimal and adventitial sites may be a consequence of tissue remodelling and cellular proliferation, while the appearance of ACE in abnormal sites could play a role in AII production by the vessel wall. The role of ACE and AII in the developing atheroma-like lesions needs to be investigated further.

High-frequency spontaneous mutation of classical Vibrio cholerae to a nonmotile phenotype

The species Vibrio cholerae contains within it two biotypes, classical and El Tor, both of which are motile. Phenotypic expression of motility was unaffected by type of growth medium, salt concentration, pH, or temperature of incubation. However, seven strains of classical V. cholerae produced spontaneous nonmotile mutants at an unusually high frequency (ca. 10(-4)), while no mutants were detected for all three El Tor strains examined. No revertants of these nonmotile mutants were detected. Four independent mutants of classical strain 395 were isolated to characterize this phenomenon. By transmission electron microscopy, one of the nonmotile mutants was found to be flagellated, while the other three were found to be aflagellate. Chromosomal DNA from the mutants and parental wild-type strain 395 was examined by Southern blot analysis with, as probes, V. cholerae mutagenic prophages VcA-1 and VcA-2 and six cloned motility gene regions isolated from transposon insertion motility mutants of strains 395 and N16961 (El Tor, Inaba). The parental wild-type strain and all of the mutants exhibited the same pattern of bands when probed with VcA-1 and VcA-2 DNAs. Four of the cloned motility gene regions hybridized to the same fragments of DNA in both the wild-type and mutant isolates. However, two other probes detected a new fragment for a single aflagellate mutant. The observations that spontaneous nonmotile mutants occurred at a high frequency and that these mutants did not revert at a detectable frequency suggested that a genetic event is involved. The phenomenon appears to be limited to classical V. cholerae and may explain why classical V. cholerae is only sporadically associated with disease in the current pandemic.