[Imaging of the thorax with multislice spiral CT]

With multislice spiral computed tomography (MSCT), existing indications for performing CT of the chest are strengthened and new applications are emerging. The high speed of MSCT improves efficiency, image quality and patient comfort of "routine" imaging of the chest. The ability to cover large volumes with thin slices improves the evaluation of mediastinal lymph nodes and pulmonary nodules and allows for high-quality secondary reconstruction. If a comprehensive diagnosis of the mediastinal structures and the pulmonary parenchyma is desired, MSCT for the first time allows reconstruction of contiguous and high-resolution (HRCT) sections from the same set of thin-collimation raw data. This way, contiguous chest images of superior and HRCT sections of equal image quality compared to conventional CT scanning can be obtained. Vascular protocols greatly benefit from the high speed of MSCT: For imaging the thoracic aorta or pulmonary emboli (PE), the amount of contrast material can be substantially reduced. Owing to thin collimation, the detection rate of small peripheral emboli can be significantly increased. If indicated, the entire subphrenic venous system can be evaluated during the same session, without additional contrast material.

[Computed tomography of the abdomen with multidetector-array CT]

BACKGROUND

The advent of multidetector CT (MDCT) constitutes a quantum leap creating a wealth of new opportunities in medical imaging. However, while the basic principles of spiral CT still apply, we are now challenged to rethink our strategies in planning a CT study to take full advantage of the increased capabilities of MDCT.

MATERIALS AND METHODS

We report here our preliminary experiences with MDCT for abdominal CT imaging within a 5-month period. During this time, suitable protocols for investigation of the abdomen using MDCT were developed. The capabilities of MDCT allow for tailoring dedicated CT protocols for routine applications as well as for biphasic liver studies and CT angiography of the aorta and abdominal vessels.

RESULTS

The speed of MDCT can either be used to reduce the time needed to cover a given volume, or to use narrower beam collimations to increase the resolution of detail along the z-axis and reduce volume averaging. Higher scan speed allows reduction of the amount of contrast material in vascular applications and suppression of motion artifacts. Higher spatial resolution with thinner collimations reduces volume averaging and improves the detection of small hepatic and pancreatic lesions. Detailed analysis of vascular structures and high-quality three-dimensional reformations become feasible. New problems arise from the large amount of data generated by MDCT.

CONCLUSIONS

MDCT offers a wealth of new opportunities that help us to come to a fast and accurate diagnosis in suspected abdominal disease. Traditional indications for performing CT are reemphasized and new clinical applications can be exploited.

Preoperative cooling and warming of the donor site increase survival of skin flaps by the mechanism of ischaemic preconditioning: an experimental study in rats

Recent studies show that survival of skin flaps can be increased by ischaemic preconditioning with repeated cycles of ischaemia and reperfusion before prolonged ischaemia or raising of the flap. In this study three cycles of cooling and warming of rat dorsal skin were used to regulate skin blood flow and to induce three cycles of ischaemia and reperfusion. In 10 Sprague-Dawley rats three cycles of cooling (-18 degrees C ice pack) and warming (45 degrees C running water) were used to regulate skin blood flow before the flaps were raised. Caudally-based skin flaps 11 x 2 cm were then raised to the left of the dorsal midline and sutured back. In the control group (n = 9) the flap was raised and sutured back without any treatment. Viability was assessed after seven days and the survival area calculated with planimetry. Viability increased from a mean (SD) of 61 (6)% in the control group to 77 (7)% in the experimental group (p < 0.0001). This study shows that preoperative cooling and warming of the donor site can be used to increase survival of skin flaps. The probable explanation is ischaemic preconditioning although the biochemical mechanism is unclear.

Cyclosporine attenuates pressure-overload hypertrophy in mice while enhancing susceptibility to decompensation and heart failure

Left ventricular hypertrophy (LVH) is a compensatory mechanism to cope with pressure overload. Recently, a calcineurin pathway mediating LVH and its prevention by cyclosporine was reported. We examined whether calcineurin mediates LVH due to pressure overload in mice. Pressure overload was induced by aortic banding in 53 mice (32 treated with cyclosporine [25 mg. kg-1. d-1], 21 treated with vehicle). There were 17 sham-operated mice (9 treated with vehicle, 8 treated with cyclosporine). At 3 weeks after surgery, LV weight to body weight was greater in the nontreatment banded group (4.39+/-0. 16 mg/g) than in the cyclosporine-treated banded group (3.95+/-0.14 mg/g, P<0.05), with both groups being greater compared with the entire group of sham-operated mice (3.02+/-0.04 mg/g). The pressure gradient between the ascending and abdominal aorta was not different between the cyclosporine-treated (49.6+/-6.1 mm Hg) and nontreatment groups (48.7+/-4.6 mm Hg). Although LV systolic pressure was lower in the cyclosporine-treated banded animals, LV systolic wall stress was similar in the nontreatment banded group and in the cyclosporine-treated group. However, LV dP/dt was lower (P=0.05) in the cyclosporine-treated banded group (4774+/-656 mm Hg/s) than in the nontreatment banded group (6604+/-516 mm Hg/s). During the protocol, 23 of 32 mice in the cyclosporine-treated group and 9 of 21 mice in the nontreatment group died. All deaths occurred within 10 days after surgery. Deaths caused by heart failure were 7.2-fold higher (P<0.05) in the cyclosporine-treated group, whereas deaths due to other causes were not different between the 2 groups. In addition, LV function of mice was assessed at 48 hours after banding; LV ejection fraction measured with echocardiography was lower (P<0.05) in the cyclosporine-treated banded group (66+/-3.0%) than in the nontreatment banded group (79+/-1.5%), whereas LV systolic wall stresses were similar. Calcineurin phosphatase activity was depressed similarly in both cyclosporine-treated groups compared with both nontreatment groups. Thus, cyclosporine could attenuate, but not prevent, LVH at the expense of inhibiting an important compensatory mechanism in response to pressure overload, resulting in reduced LV wall stress and function and increased susceptibility to decompensation and heart failure.

A prospective analysis of cognitive function and anticardiolipin antibodies in systemic lupus erythematosus

OBJECTIVE

To prospectively analyze the association between changes in cognitive function and circulating anticardiolipin antibodies (aCL) over a period of 5 years in patients with systemic lupus erythematosus (SLE).

METHODS

Cognitive function was assessed in 51 unselected female SLE patients at baseline and after a mean followup of 64.5 months (range 52-71 months), using standardized tests of cognitive function, i.e., the Wechsler Adult Intelligence Scale-Revised, the Wechsler Memory Scale-Revised, and the California Verbal Learning Test. Circulating IgG, IgA, and IgM aCL and anti-double-stranded DNA (anti-dsDNA) antibody levels were determined by enzyme-linked immunosorbent assay on 4-7 occasions over the same time period. Persistent antibody reactivity was defined as levels more than 2 standard deviations (moderately positive) and more than 5 standard deviations (highly positive) above the mean for normal controls over the duration of the study. Changes in overall cognitive performance and in raw scores on individual cognitive tests were compared in patients who were persistently positive or negative for aCL.

RESULTS

At baseline 11 patients (22%) were cognitively impaired, compared with 7 (14%) at followup. Between 16% and 37% of patients had persistently elevated aCL levels of different isotypes. There was no significant difference in the prevalence of overall cognitive impairment in patients who were persistently positive for aCL compared with those who were not. In contrast, over the period of study, patients who had persistent IgG aCL positivity had a reduction in psychomotor speed, and patients who had persistent IgA aCL positivity had a reduction in conceptual reasoning and executive ability. Similar associations with anti-dsDNA antibodies were not found.

CONCLUSION

These results suggest that IgG and IgA aCL may be responsible for long-term subtle deterioration in cognitive function in patients with SLE.

Indole-3-carbinol and tamoxifen cooperate to arrest the cell cycle of MCF-7 human breast cancer cells

The current options for treating breast cancer are limited to excision surgery, general chemotherapy, radiation therapy, and, in a minority of breast cancers that rely on estrogen for their growth, antiestrogen therapy. The naturally occurring chemical indole-3-carbinol (I3C), found in vegetables of the Brassica genus, is a promising anticancer agent that we have shown previously to induce a G1 cell cycle arrest of human breast cancer cell lines, independent of estrogen receptor signaling. Combinations of I3C and the antiestrogen tamoxifen cooperate to inhibit the growth of the estrogen-dependent human MCF-7 breast cancer cell line more effectively than either agent alone. This more stringent growth arrest was demonstrated by a decrease in adherent and anchorage-independent growth, reduced DNA synthesis, and a shift into the G1 phase of the cell cycle. A combination of I3C and tamoxifen also caused a more pronounced decrease in cyclin-dependent kinase (CDK) 2-specific enzymatic activity than either compound alone but had no effect on CDK2 protein expression. Importantly, treatment with I3C and tamoxifen ablated expression of the phosphorylated retinoblastoma protein (Rb), an endogenous substrate for the G1 CDKs, whereas either agent alone only partially inhibited endogenous Rb phosphorylation. Several lines of evidence suggest that I3C works through a mechanism distinct from tamoxifen. I3C failed to compete with estrogen for estrogen receptor binding, and it specifically down-regulated the expression of CDK6. These results demonstrate that I3C and tamoxifen work through different signal transduction pathways to suppress the growth of human breast cancer cells and may, therefore, represent a potential combinatorial therapy for estrogen-responsive breast cancer.

Suicidal behavior among young people in Singapore

The purpose of this study was to investigate suicidal behavior among young people in an Asian community. Tracing records of all patients below 21 years of age who attempted suicide and were managed in a teaching hospital, the authors found the incidence increased sixfold between 1991 and 1995. Young females of Indian origin were found to be a risk group. Differences in suicidal behavior among the three main ethnic communities appear to be influenced by various sociocultural factors. The most common diagnosis was adjustment disorder stemming from interpersonal losses and conflicts. Schizophrenia, alcohol, and other substance abuse were rarely reported.

Quantitative PCR for Listeria monocytogenes with colorimetric detection

An enzyme-linked immunosorbent assay (ELISA)-mediated polymerase chain reaction (PCR) technique was developed to detect and quantify Listeria monocytogenes in food products. The bacterial DNA was extracted from artificially contaminated food and co-amplified with a synthetic internal standard (IS) using primers specific for the target gene coding for the invasive-associated protein (i.a.p.), a virulence factor of L. monocytogenes (i.a.p.) or IS in the presence of fluorescein-dUTP PCR products were hybridized with biotinylated probes designed for the i.a.p. or IS, and then the hybrids were bound to a streptavidin-coated ELISA plate. An alkaline phosphatase-conjugated antibody to fluorescein was added to the plate and in the presence of substrate, PCR products were quantitated based on an optical density reading. The detection limit for L. monocytogenes experimentally inoculated into milk samples and channel catfish fillets was 20 CFU/ml and 1-2 CFU/g, respectively. Little or no cross reaction was detected in the presence of other spoilage and pathogenic organisms such as Pseudomonas aeruginosa, Aeromonas hydrophila, Escherichia coli, and Staphylococcus aureus. The ELISA-mediated PCR technique, when compared to traditional methods, is more rapid (2 working days) for detecting and quantifying L. monocytogenes.

Effect of trilinolein on strophanthidin-induced ventricular tachycardia in guinea pigs

Trilinolein, a triacylglycerol with linoleic acid, was found to inhibit Ca2+ influx in cardiomyocytes. The purpose of this study was to evaluate the effects of trilinolein on ventricular arrhythmia induced by intravenous strophanthidin in guinea pigs anesthetized with intraperitoneal urethane. After strophanthidin- induced ventricular tachycardia, treatment with trilinolein (0.1, 1, 10 and 100 microg/kg) or control (0.04% propylene glycol) did not terminate ventricular tachycardia. However, 1, 10 and 100 microg/kg trilinolein could narrow the width of the QRS complex during ventricular tachycardia. Pretreatment with trilinolein before strophanthidin administration did not prevent the occurrence of ventricular tachycardia; the doses of strophanthidin required to induce arrhythmias (ventricular extrasystole and ventricular tachycardia) were similar in guinea pigs pretreated with trilinolein or control. However, there were fewer ventricular extrasystoles in guinea pigs pretreated with trilinolein than in the control group (ANOVA, p < 0.01). Moreover, the ventricular extrasystoles were fewer in guinea pigs pretreated with higher doses of trilinolein (100 microg/kg, 103 +/- 60; 10 microg/kg, 188 +/- 86) than lower doses of trilinolein (1 microg/kg, 366 +/- 102; 0.1 microg/kg, 436 +/- 145). This study demonstrated that trilinolein was not effective in terminating or preventing strophanthidin-induced ventricular tachycardia. However, trilinolein could improve ventricular depolarization and suppress ventricular extrasystoles.

Reversal of optic disc topography in patients with glaucomatocyclitic crisis after remission of attack

PURPOSE

The authors investigate change in optic disc topography after reduction of intraocular pressure (IOP) in patients with glaucomatocyclitic crisis.

METHODS

During the attack of elevated IOP and after remission six eyes of six consecutive patients (46.3 +/- 12.7 years of age, 6 men) underwent optic disc imaging using confocal scanning laser tomography. For each imaging of one eye, a mean topograph was acquired after triple measurements with 15 degrees of field. Topical 0.5% timolol maleate and 1% prednisolone acetate with or without oral carbonic anhydrase inhibitor were administered after optic disc topography during the attack. The average time interval between the imaging during attack and after remission was 38.5 days (range, 21-87 days).

RESULTS

Mean IOP during the attack and after remission, and percent decrease in IOP were: 43.3 +/- 10.4 mmHg, 13.5 +/- 6.5 mmHg, and 69.4 +/- 10.2%, respectively. Significant decreases in cup area, cup volume, cup/disc area ratio, and mean cup depth and significant increases in rim area and rim volume were observed after IOP reduction (Wilcoxon signed rank test). Significant associations were found between percent decrease in IOP and percent decrease in cup volume and percent increase in rim area and rim volume.

CONCLUSION

In patients experiencing glaucomatocyclitic crisis, reversal of optic disc topography were associated with reduction of IOP.

Temporal variation in parasuicide among Singaporean Chinese

OBJECTIVE

The aim of this study was to determine whether there is any temporal variation in the incidence of parasuicide within the Chinese community and, if possible, to correlate the findings with prevailing cultural and social influences.

METHOD

All patients of Chinese origin referred to a teaching hospital in Singapore between 1990 and 1994 were included in the study. The cases were divided by sex and aggregated for the month and day of the week in which the parasuicides occurred.

RESULTS

Cases of parasuicide peaked on Mondays, while the lowest incidences occurred on Saturdays. The peak months were June, August and September with a trough in December and January.

CONCLUSIONS

The findings may not be amenable to any single explanation but the peak months coincided with the month of the Hungry Ghosts, which is believed to be a particularly inauspicious period, while the trough occurred during a festive period. Similarly, looking at the student population, the peaks coincided with the examination period. It appears that social and cultural factors play a significant role in the temporal variation in parasuicide in Singapore.

Peripapillary atrophy in normal and primary open-angle glaucoma

This study was undertaken in order to determine the value of measuring peripapillary atrophy for the diagnosis and follow-up of patients with glaucoma, and to evaluate how closely peripapillary atrophy is related to structural and functional optic nerve damage in glaucoma. Magnification-corrected morphometry of photographs using a computer graphic program and automated static threshold perimetry were performed in 234 eyes of 141 patients with primary open-angle glaucoma and 139 eyes of 86 normal subjects. The groups were not significantly different in age, refractive error or disc area. Zones alpha and beta were significantly larger, total peripapillary atrophy was significantly more extensive, and zone beta occurred more often in the glaucoma group than in the normal group. The frequency of zone beta increased with advancing glaucoma stage. The areas of zones alpha and beta and total peripapillary atrophy increased significantly with decreasing rim/disc area ratio, rim area, and mean deviation, and with increasing vertical and horizontal cup-to-disc ratios and cup area. Correlation coefficients were generally higher for zone beta than for zone alpha. Peripapillary atrophy was greater in a sector in which the neuroretinal rim loss was more marked. These findings suggest that increases in the extent of peripapillary atrophy are related to the severity of glaucomatous optic nerve damage and visual field defects, and that peripapillary atrophy is useful for the diagnosis and progression of glaucomatous nerve damage.

Retinal vessel diameter in normal and primary open-angle glaucoma

The purpose of this study was to determine how closely peripapillary retinal vessel diameter is related to functional and structural optic nerve damage in primary open-angle glaucoma. Using optic disc photographs of 234 eyes of 141 patients with primary open-angle glaucoma and 139 eyes of 86 normal subjects, the diameters of the superior and inferior temporal retinal arteries and veins were measured at the optic disc border. On the basis of rim/disc area ratio, the glaucoma group was divided into four stages: early, more than 0.61; medium, 0.60-0.41; advanced, 0.40-0.21; far advanced, less than 0.20. In the normal group the diameter of the inferior temporal vein was the largest, followed by that of the superior temporal vein, the inferior temporal artery, and the superior temporal artery. The diameters of the inferior and superior temporal retinal artery were significantly smaller at the early and medium stage, respectively, whereas both inferior and superior temporal retinal vein diameters were significantly smaller at the far advanced stage. The diameters of the inferior and superior temporal retinal arteries correlated significantly with neuroretinal rim area (r > or = 0.48, P = 0.0001), mean deviation (r > or = 0.42, P = 0.0001), vertical cup-to-disc ratio (r < or = -0.33, P = 0.0001), and peripapillary atrophy data (r < or = -0.14, P < 0.04). The results indicate that in primary open-angle glaucoma, vessel diameter becomes less as neuroretinal rim area decreases and visual field defects and peripapillary atrophy increase. Its evaluation can be helpful for the diagnosis of glaucoma and possibly also during follow-up.

Prognostic factors for adenocarcinoma of the gallbladder: an analysis of 162 cases

Carcinoma of the gallbladder is a rare neoplasm and is associated with a dismal prognosis. To analyze the natural history of this disease and prognostic factors, a large tumor registry database was accessed. During the period 1972 to 1995, 214 patients were entered. Adequate follow-up was available on 162 patients, and this group forms the basis of this review. There were 54 males and 108 females with a median age of 62 years. Median follow-up was 7 months. Right upper quadrant abdominal pain was the most frequent presenting symptom. Fifteen patients had an incidental finding of carcinoma after cholecystectomy. Overall, 5-year survival was 25 per cent, with a median survival time of 9.7 months. Survival was improved for patients with local disease compared with those with regional or metastatic disease. One hundred nine patients underwent surgical therapy. Complete resection was possible in 36 patients, whereas 44 patients had residual disease. Median survival time for patients with no residual disease was 67.2 months, whereas those for patients with microscopic residual tumor and gross residual tumor were 8.9 and 3.8 months, respectively (P < 0.000001). Gallbladder cancer is often diagnosed at an advanced stage and is associated with a poor prognosis. In patients with localized disease, surgical treatment provides the opportunity for long-term survival only when a complete resection can be performed. Prognosis for patients with microscopic residual and gross residual disease is similar.

Geographic and demographic differences in the frequency of human cytomegalovirus gB genotypes 1-4 in immunocompromised patients

To test the hypothesis that human cytomegalovirus (CMV) gB genotype may differ with geographic origin or patient demographics, CMV DNA was amplified for gB typing from immunocompromised patients in Italy and Africa and compared with previously reported frequencies in California. Increased gB2 frequency occurred in Italian homosexual AIDS patients, as compared with both Italian heterosexual injection drug users with AIDS and heterosexual Zimbabwe AIDS patients. Occurrence of gB3 in Italy was higher in injection drug users than in homosexual AIDS patients. The incidence of gB4 was higher overall in the Italian as compared with the California patients. Therefore geographic and demographic differences in patients affect gB distribution and should be considered before associations of gB genotypes and virulence are made.

The role of internal urease in acid resistance of Helicobacter pylori

BACKGROUND & AIMS

The relative role of internal urease for acid protection of Helicobacter pylori is unknown. The aim of this study was to determine the comparative importance of internal and external urease under acidic conditions.

METHODS

The pH optimum and measured Michaelis constant for urea of external urease and urease in intact bacteria at different medium pH (pHout) were measured using 14CO2 release from 14C-urea. The effect of urea on membrane potential and bacterial cytoplasmic pH was measured at different fixed pHout. 35S-methionine labeling and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of labeled proteins in the organism and medium measured protein synthesis at different pHout and mechanisms of urease externalization.

RESULTS

External urease had activity between pH 5.0 and 8.5 and internal urease between pHout 2.5 and 6.5, and its Michaelis constant at pHout 7.5 was 300 mmol/L but at pHout 4.5 was 0.5 mmol/L, similar to free urease. The addition of 5 mmol/L urea to bacteria at fixed pHout from 3.0 to 6.0 elevated potential to about -105 mV and periplasmic pH to about pH 6.2. Protein synthesis occurred mainly between pH 6.5 and 8.0, and urease activity resulted in increased protein synthesis at acidic pH. The labeling pattern of intrabacterial and released protein was similar.

CONCLUSIONS

Intracellular urease activity is regulated by external pH, defends against gastric acidity by increasing periplasmic pH and membrane potential, and stimulates protein synthesis at acidic pH. External urease is produced mostly by cell lysis.

Application of thrombin based fibrin glue and non-thrombin based batroxobin glue on intact human blood vessels: evidence for transmural thrombin activity

An alternative method of uniting small diameter vessels to obtain tissue union while limiting the thrombogenic effect of suture placement at a vessel anastomosis involves the use of a thrombin based fibrin glue as a surgical sealant. This investigation addresses whether the in vitro application of a thrombin based glue (TG), or batroxobin glue (BG), a non-thrombin based glue made with the snake venom enzyme batroxobin, alters intravascular platelet deposition (PD) or cleaves blood fibrinogen, as measured by fibrinopeptide A (FPA) production, when the respective glue is applied to the external surface of an intact human placental artery or an artery with an anastomosis. When TG was applied to the adventitial surface of an intact vessel or an anastomosis (n = 7) of control and experimental vessels, there was a significant increase in intraluminal platelet deposition, an effect not realized with BG (n = 12, intact vessel TG p = 0.01, BG p = 0.66, anastomosis TG p <0.01, BG p <0.01). Both TG and BG significantly increased FPA levels when human whole blood was perfused through both intact vessels or vessels containing an anastomosis when compared to control vessels (intact vessel TG and BG p <0.01, anastomosis TG and BG p <0.01). Labelled thrombin studies document the rapid passage of thrombin through an intact vessel wall or vessels with an anastomosis when TG was applied to the adventitial surface of the vessel. The data suggest that TG and BG are drug delivery systems for their respective enzymes that either pass through or transfer a message across not only a surgically created anastomosis, but also an intact vessel wall.

Roles of rDNA spacer and transcription unit-sequences in X-Y meiotic chromosome pairing in Drosophila melanogaster males

Meiotic pairing of the X and Y chromosomes in Drosophila melanogaster males is mediated by the rDNA repeats, which are present in two tandem clusters, one in the centric X heterochromatin and the other near the base of the short arm of the Y chromosome. Deletion of the X chromosomal rDNA cluster disrupts X-Y pairing and causes high frequences of X-Y nondisjunction. Pairing can be partly restored by insertions of cloned complete rRNA genes or by rDNA fragments that include the intergenic spacer (IGS) region. A 240 bp repeated sequence in the IGS was shown to be effective in promoting pairing when present at copy numbers above five. This study further defines the rDNA sequences involved in mediating pairing. Germline insertions of a P element construct containing most of the rDNA transcription unit but no promoter or IGS region were obtained. Two single-copy insertions and four two-copy insertions proved unable to stimulate X-Y disjunction when located on an rDNA-deficient X chromosome. In addition, three insertions of a P element construct consisting of the IGS and promoter regions of the rDNA were characterized molecularly. These three insertions had previously been shown to range in pairing ability from very weak to quite strong. Molecular analysis revealed that the three insertions also vary in copy number of the 240 bp IGS repeat and that these structural differences correlate with the differences in pairing ability. These data indicate that 240 bp repeats are considerably more effective than other regions of the rDNA in stimulating chromosome pairing.

Serotonin levels as a function of age in Aplysia californica

The neurotransmitter serotonin (5-HT) plays an important role in a number of behaviors in Aplysia californica some of which have been shown to vary with age. We were thus interested in examining the age-dependence of 5-HT in A. californica. Because animals of the same age can have very different weights, and weight alone is reliably known for wild-caught animals, we also examined the variation of 5-HT with weight. Serotonin was measured in the ring and abdominal ganglia combined, in lab-reared animals from 3 to 12 months post-hatch across a wide weight range. Serotonin increased rapidly from 4 to 6 months, and more slowly from 6 to 13 months. Serotonin scaled by soluble ganglion protein increased from 3 to 6-7 months, reached a maximum, and then decreased again. Serotonin, but not scaled 5-HT, increased significantly with weight across the whole weight range. Animals of the same weight, but different ages, had different 5-HT levels, as did young animals of the same age but different weight. Serotonin varied significantly with both age and weight, with the age-dependence being the more significant.

Identification and differentiation of mycobacteria using the PAN promoter sequence from Mycobacterium paratuberculosis as a DNA probe

A 165 bp DNA fragment containing the PAN promoter from Mycobacterium paratuberculosis was used as a probe in Southern blots to detect the presence of related sequences in other species of mycobacteria. Among the species tested homologous sequences appeared to be present in representative pathogens belonging to the Mycobacterium tuberculosis complex, the MAIS complex, Mycobacterium kansasii and also the non-pathogenic vaccine strain Mycobacterium bovis BCG. In addition, the probe could differentiate between these species on the basis of a restriction fragment length polymorphism (RFLP). No hybridization was observed with DNA extracted from a selected group of other slow-growing and fast-growing mycobacteria nor from a selection of other bacterial pathogens. It appears that the PAN sequence is identifying genomic regions common to the major pathogenic groups of mycobacteria.

Cytomegalovirus gB genotype distribution differs in human immunodeficiency virus-infected patients and immunocompromised allograft recipients

Cytomegalovirus isolates can be grouped into 4 gB and 2 gH genotypes. gB genotypes were studied in patients infected with human immunodeficiency virus (HIV) and in allograft transplantation recipients. In allograft recipients, the distribution of gB 1, -2, -3, and -4 in leukocytes and urine, respectively, was 36%, 21%, 43%, and 0% and 39%, 30%, 17%, and 13%. However, in leukocytes of HIV-infected patients with <100/microL CD4 cells, gB1 was found significantly less often than in allograft recipients (11% vs. 36%) but gB2 was more frequent (56% vs. 21%; P < .05). The decreased incidence of gBl and increased incidence of gB2 compared with allograft recipients was also seen in urine of HIV-infected patients and reflected the distribution seen in leukocytes. gB4 was found significantly more often (P < .05) in semen than in leukocytes of HIV-infected patients with < 100/microL CD4 cells. gB1-4 genotypes were similar in patients with < 100/microL CD4 cells with or without retinitis.

Detection of Francisella tularensis by the polymerase chain reaction

Francisella tularensis is the causative agent of tularaemia. Effective antibiotic treatment of tularaemia is now available, but the early diagnosis of tularaemia remains a problem. Four primers (three pairs) were designed to detect F. tularensis by the polymerase chain reaction (PCR), based on the previously published nucleotide sequence of T-cell epitopes of a F. tularensis membrane protein. Amplification of purified F. tularensis chromosomal DNA with the three pairs of primers resulted in three different products with sizes consistent with those predicted from sequence data (211 bp, 347 bp and 568 bp). The specificity of the PCR was confirmed as no amplification was detected with a range of other bacteria. The sensitivity of the PCR was determined with limiting dilution PCR and viable counts. The preliminary application of the PCR to the detection of F. tularensis in aerosols and experimentally infected mice was investigated. Comparison of the results with those from traditional culture indicated that PCR was more sensitive. The animal challenge test showed that, 24 h after inoculation with 15 cfu of F. tularensis, 38 (82.6%) of 46 blood samples were positive by PCR, whereas only 22 (47.8%) were positive by culture. The results showed that PCR is a helpful tool for the detection of F. tularensis in blood, liver and spleen which should enable the rapid confirmation of clinical diagnoses of tularaemia.

Beta 2-glycoprotein I and anticardiolipin antibody binding to resting and activated cultured human endothelial cells

OBJECTIVE

To examine beta 2-glycoprotein I (beta 2-GPI) binding and its ability to augment IgG anticardiolipin (aCL) antibody binding to resting and cytokine activated endothelial cells in vitro. To evaluate the ability of IgG aCL antibody positive sera to induce endothelial cell activation in vitro.

METHODS

IgG with aCL activity was isolated by affinity purification from 6 patients with systemic lupus erythematosus (SLE) and 3 patients with primary antiphospholipid antibody syndrome (APS). Human umbilical vein endothelial cells (HUVEC) were cultured in serum-free conditions and examined in a resting state or after activation with tumor necrosis factor alpha (TNF-alpha). HUVEC were exposed to beta 2-GPI alone, IgG alone or IgG plus beta 2-GPI. Finally, we examined the ability of sera from the same patients with SLE and primary APS to activate HUVEC in culture.

RESULTS

Neither beta 2-GPI, IgG aCL, nor IgG aCL plus beta 2-GPI bound to resting or cytokine activated endothelial cells. In addition, sera from the same patients did not induce in vitro activation of endothelial cells as assessed by enhanced surface expression of intercellular adhesion molecule, vascular cell adhesion molecule, and E-selectin.

CONCLUSION

Results suggest that beta 2-GPI deposition on either resting or activated endothelial cells and modulation of its proposed in vivo anticoagulant activity through subsequent aCL antibody binding does not account for the thrombotic manifestations of APS.

Occurrence of anthelmintic resistant nematodes on sheep farms in England and goat farms in England and Wales

A survey in 1992 showed that 44 per cent of the sheep farms tested in the south west and 15 per cent of those in the north east of England had parasitic nematode worm burdens which were resistant to benzimidazole anthelmintics, and that 65 per cent of the non-dairy goat farms tested in England and Wales had resistant worms. Ostertagia circumcincta was the main species in sheep and Haemonchus contortus in goats. The resistance to benzimidazoles was diagnosed by a combination of an egg hatch assay and a larval development test. A simplified faecal egg count reduction test was used to investigate sheep and goat farms for signs of ivermectin resistance but no positive cases were detected. The initial identification of levamisole resistance on one farm, both from a faecal egg count reduction test and a positive larval development test, was confirmed by a 'dose and slaughter' trial.

Expression of IFN regulatory factor family proteins in lymphocytes. Induction of Stat-1 and IFN consensus sequence binding protein expression by T cell activation

Interferon consensus sequence binding protein (ICSBP) is a transcription factor of the IFN regulatory factor (IRF) family. Evidence indicates that this family has a function in the immune system. Unlike other members of the family, ICSBP is expressed exclusively in the immune system. In this work, immunoblot analysis was performed to study expression of ICSBP and other members of the family in various murine lymphocytes. The results show that all IRF family members are expressed constitutively in B cells throughout development, and in resting and activated cells. In contrast, ICSBP expression was undetectable in thymocytes and resting T cells, while all other IRF proteins tested (IRF-1, IRF-2, and ISGF3-gamma) were detected in these cells. Induction of ICSBP (and weakly IRF-1, but not other members) was observed upon activation of T cells following anti-CD3 Ab binding or Con A stimulation. Once T cells were activated, ICSBP was expressed stably in both Th1 and Th2 cells. We show that Stat-1, which binds to the IFN-gamma-responsive element of the ICSBP promoter, was induced following anti-CD3 Ab and Con A stimulation. Stat-1 induction was found in T cells of IFN-gamma+/+, but not of IFN-gamma-/- mice, indicating that T cell activation stimulates the Stat pathway of transcription that is mediated through IFN-gamma. IFN-gamma-activated Stat-1 partly accounted for ICSBP induction in activated T cells, as levels of induction were lower in IFN-gamma-/- than in IFN+/+ T cells. Taken together, these results show that activation of ICSBP is coupled with T cell activation that is partly due to IFN-gamma-induced Stat-1.

Expression of IFN regulatory factor family proteins in lymphocytes. Induction of Stat-1 and IFN consensus sequence binding protein expression by T cell activation

Interferon consensus sequence binding protein (ICSBP) is a transcription factor of the IFN regulatory factor (IRF) family. Evidence indicates that this family has a function in the immune system. Unlike other members of the family, ICSBP is expressed exclusively in the immune system. In this work, immunoblot analysis was performed to study expression of ICSBP and other members of the family in various murine lymphocytes. The results show that all IRF family members are expressed constitutively in B cells throughout development, and in resting and activated cells. In contrast, ICSBP expression was undetectable in thymocytes and resting T cells, while all other IRF proteins tested (IRF-1, IRF-2, and ISGF3-gamma) were detected in these cells. Induction of ICSBP (and weakly IRF-1, but not other members) was observed upon activation of T cells following anti-CD3 Ab binding or Con A stimulation. Once T cells were activated, ICSBP was expressed stably in both Th1 and Th2 cells. We show that Stat-1, which binds to the IFN-gamma-responsive element of the ICSBP promoter, was induced following anti-CD3 Ab and Con A stimulation. Stat-1 induction was found in T cells of IFN-gamma+/+, but not of IFN-gamma-/- mice, indicating that T cell activation stimulates the Stat pathway of transcription that is mediated through IFN-gamma. IFN-gamma-activated Stat-1 partly accounted for ICSBP induction in activated T cells, as levels of induction were lower in IFN-gamma-/- than in IFN+/+ T cells. Taken together, these results show that activation of ICSBP is coupled with T cell activation that is partly due to IFN-gamma-induced Stat-1.

Adjusting the evaluation limit for broad-band whole-body vibration

The vibration levels of 87 axes in 29 conventional vehicles were measured, recorded, and analyzed. The mean deviation of the overall frequency-weighted vibration levels (Lw) and the greatest single one-third octave band frequency-weighted vibration levels (Lwi-max) in corresponding axes were statistically calculated. The results showed that the vehicle vibrations were broad-band vibrations. The mean deviation of Lw - Lwi-max is 6 dB. This article suggests a 6 dB value as an appropriate adjustment value for evaluating broad-band whole-body vibrations of vehicles when using the most sensitive limits given in International Organization for Standardization document 2631/1.

Prostacyclin production at the human microvascular anastomosis: its effect on initial platelet deposition

The human microvascular anastomosis represents a localized environment with strongly thrombotic tendencies. In previous studies, an increase in initial platelet deposition at a human ex vivo anastomosis was measured. It is postulated that this increase in anastomotic platelet deposition was due to a reduction in anastomotic prostacyclin production as a consequence of local endothelial cell injury or loss. Instead, in this study, an increase in anastomotic prostacyclin production over unsutured controls (control 1093 +/- 222 pg/ml of 6-keto prostaglandin F (PGF) 1-alpha, n=21; anastomosis 2494 +/- 414, n=21, mean +/- 1 SEM, p=0.005) is demonstrated. Anastomotic prostacyclin production was augmented by addition of arachidonic acid (0.1 mM) (39,000 +/- 11,300 pg/ml of 6-keto PGF 1-alpha, n=7, p<0.001) and suppressed by the preincubation of vessel segments with aspirin in a dose-dependent fashion (1mM) (83+/-22 pg/ml of 6-keto PGF 1-alpha, n=21, p<0.001); aspirin (0.1 mM) (312 +/- 56 pg/ml of 6-keto PGF 1-alpha, n=7, p<0.001). In further studies using a perfusion apparatus of human blood pumped through human placental artery segments, suppression of prostacyclin production did not augment initial platelet deposition (control anastomosis 4.9 +/- 2.2 x10(6) platelets per cm2, aspirin treatment 6.0 +/- 2.8 x 10(6) platelets per cm2, n=5, mean +/- 1 SEM, p>0.05). Suppression of platelet function with aspirin (0.1 mM) also did not decrease initial platelet deposition onto the anastomosis (5.8 +/- 2.8 x 10(6) platelets per cm2, n=r, p>0.05). In this model system, initial platelet deposition at the anastomosis may not be dependent upon cyclooxygenase pathways.

VH gene usage is multiple myeloma: complete absence of the VH4.21 (VH4-34) gene

The immunoglobin heavy chain variable region (VH) gene usage in multiple myeloma (MM) has not been reported, although a few studies have incidentally identified the VH gene rearranged in small cohorts of MM patients. We used a reverse transcriptase-polymerase chain reaction based technique to analyze the VH gene usage in MM. The VH sequences were obtained after amplification of bone marrow cDNA using the seven VH family-specific and constant region primers. The VH sequences of 72 patients were successfully identified. The frequency of VH family usage in decreasing order was VH3>VH4>VH1>VH5>VH2>VH6>VH7 and corresponded to the functional germline complexity of the VH families. Individual VH genes (VH1-69, VH3-9, VH3-23, and VH3-30) were overrepresented in our cohort of MM patients; some VH genes [VH3-49, VH3-53, and VH4.21 (VH4-34)], which are rearranged with increased frequency in normal circulating B cells, autoimmune diseases, and other B-cell malignancies, were not detected in any MM patient. Compared with germline sequences, an average of 8.8% (range, 2.7% to 16.5%) of the nucleotides had evidence of mutation within each VH sequence. Based on these results, we conclude that (1) the VH gene usage in MM is unique compared with other malignant and nonmalignant B-cell populations, (2) the physiologic process of clonal deletion functions to remove clones that have rearranged VH genes (VH4.21) capable of expressing antibodies, which recognize self-antigens, and (3) the complete lack of VH4.21 gene rearrangement may help to partially explain the paucity of autoimmune phenomena in MM.

A recA-like gene in Drosophila melanogaster that is expressed at high levels in female but not male meiotic tissues

The RecA protein is the central enzyme in prokaryotic recombination. It catalyzes pairing and strand exchange between homologous DNA molecules, and functions in both DNA repair and genetic recombination. The RecA-like proteins Rad51 and Dmc1 of yeast are both required for meiotic recombination and the former is also necessary for repair of double-strand breaks in vegetative cells. Genes encoding Rad51 homologs have been isolated recently from several higher eukaryotes. This paper describes the isolation and molecular characterization of a genomic DNA fragment from Drosophila melanogaster containing the coding sequence for a RecA-like protein. This protein exhibits strong sequence homology with the Rad51 proteins of budding yeast, fission yeast, chickens, mouse and humans, and slightly less (but still strong) homology with yeast Dmc1. Both in situ hybridization and Southern analysis indicate that the Rad51 gene is present only once per genome in Drosophila (at 99D on chromosome arm 3R). However, there are at least three other fragments that cross-hybridize strongly at low stringency. RNA blotting analysis detects a single transcript of about 1.35 kb that is present throughout development at low levels. Transcript levels are induced at least tenfold in ovaries, as measured by RNase protection analysis, suggestive of a role in female meiosis. Transcript levels are significantly lower in testes than in bulk RNA of adult males, however, indicating that Rad51 may be repressed in meiosis of Drosophila males.

Potential for misinterpretation of the faecal egg count reduction test for levamisole resistance in gastrointestinal nematodes of sheep

The faecal egg count reduction test (FECRT) is widely used to assess the presence or absence of levamisole resistance in gastrointestinal nematodes in sheep flocks. However, in a recent study the FECRT appeared to falsely indicate the presence of levamisole resistance. One possible explanation for this result could have been that the anthelmintic failed to completely remove all immature stages of levamisole-susceptible strains, which then developed into egg laying adults and gave misleading results in the FECRT. Artificial infection of lambs with levamisole-susceptible, benzimidazole-resistant strains of Ostertagia circumcincta, Haemonchus contortus and Trichostrongylus colubriformis was followed by treatment with levamisole when the infections were between 2 and 10 days old. Levamisole was 84%, 88% and 98% effective against these immature stages of three species, respectively. The positive control, ivermectin, was more than 99% effective against all three species. The percentage faecal egg count reduction on samples taken 11 and 20 days post-treatment with levamisole was 80% and 78%, respectively. These results demonstrate that, due to the maturation of immature stages, the FECRT based on faecal eggs counts taken 11 or more days after treatment may give results indicative of levamisole resistance despite the absence of levamisole resistant strains of gastrointestinal nematodes.

Development of immunity to lungworm in vaccinated calves treated with an ivermectin sustained release bolus or an oxfendazole pulse release bolus at turnout

The ivermectin sustained release bolus (IVSRB), when used at turnout as recommended, will provide season-long control of parasitic bronchitis, thus obviating the need for use of a lungworm vaccine. However, some concerns have been expressed that calves treated with an IVSRB will receive so little exposure to Dictyocaulus viviparus that it will compromise their immunity in subsequent grazing seasons, which would be of particular importance in dairy herds. Although there is evidence that IVSRB-treated calves can develop immunity to D. viviparus when exposed to pasture infection, it was considered worthwhile to evaluate the compatibility of the IVSRB and lungworm vaccination to allow veterinary surgeons the option of using these products concurrently when they have particular concerns about the long term immune status of replacement dairy heifers. Thirty-two dairy replacement heifers were vaccinated with two doses of lungworm vaccine and, at turnout, half the calves received an IVSRB and the remainder an oxfendazole pulse release bolus (OPRB). At the end of the grazing season four replicate bolus treated pairs and four parasite-naive calves were challenged with 1000 D. viviparus infective larvae. At slaughter there was a 95% and 93% reduction in D. viviparus burdens in the IVSRB and OPRB treated calves respectively, compared with the unvaccinated, untreated controls. These results indicate that where it is considered necessary to use lungworm vaccination in addition to an IVSRB or an OPRB, the compatibility of these products with lungworm vaccine will allow development of a protective level of immunity to D. viviparus.

Tissue factor and its inhibition at the human microvascular anastomosis

The surgically created vascular anastomosis is a thrombogenic zone of uncertain etiology. This study was designed to investigate the importance of tissue factor as a cause of human microvascular thrombogenicity. The ability of tissue factor pathway inhibitor (TFPI) to block the effect of tissue factor was also tested in this whole-vessel model system. Tissue factor activity in the presence of absence of TFPI was assayed on the luminal surface of dissected human placental arteries, on the advential surface, and also at the site of a microvascular anastomosis. Vessel wall thrombin activity was measured in the presence and absence of TFPI. Platelet deposition onto a vessel surface using a perfusion system was measured with and without TFPI. Tissue factor activity was greater on the adventitia (4.6 +/- 2.8 x 10(-4) units factor Xa generated/min) than on the endothelium (1.8 +/- 1.6 x 10(-4), P < 0.03) or at a surgically created anastomosis (2.1 +/- 1.2 x 10(-4), P < 0.04). TFPI reduced Xa generation to undetectable levels in 21 of 23 endothelial, adventitial, and anastomotic segments (P < 0.002). TFPI significantly reduced vessel wall thrombin activity in comparison to control anastomoses (control, 3.2 +/- 1.7 ng fibrinopeptide A (FPA)/(ml x min); TFPI, 1.4 +/- 1.2 ng FPA/(ml x min); P < 0.0001). TFPI reduced the platelet deposition on vessel segments with intact endothelium (no TFPI, 0.88 +/- 0.69 x 10(6) platelets/cm2; TFPI, 0.49 +/- 0.29 x 10(6) platelets/cm2; P < 0.06) and on vessel segments with anastomoses (no TFPI, 1.3 +/- 0.70 x 10(6) platelets/cm2; TFPI, 0.76 +/- 0.35 x 10(6) platelets/cm2; P < 0.02). This study demonstrates the importance of tissue factor as a thrombogenic element in a human whole-vessel model system. TFPI is effective in reducing this thrombogenicity.

Thrombin activity on dissected and anastomosed human arteries

The mechanism of anastomotic thrombosis in microvascular surgery remains poorly understood. We hypothesized that thrombin activity at anastomoses plays a major role in this process. To study this, a surgically relevant human artery anastomosis model was used to (i) measure surface thrombin activity on anastomoses and on intact vessel, (ii) determine the inhibitability of surface thrombin by heparin and recombinant hirudin (r-hirudin), and (iii) determine the anastomotic and intact vessel binding capacity for additional thrombin. Human placental artery segments were placed in chambers in which 0.2 cm2 of luminal surface was exposed to citrated platelet-poor plasma for 10 min at 37 degrees C. The fibrinopeptide A (FPA) concentration (indicating the action of thrombin on fibrinogen) in the supernatant was then measured using an ELISA assay. Intact vessels and anastomoses expressed equivalent thrombin activity that could not be inhibited by heparin at a concentration (0.3 U/ml) that is sufficient to prolong the activated partial thromboplastin time two-fold. Conversely, the concentration of heparin routinely used in intraoperative vessel irrigation solutions (50 U/ml) was able to completely block thrombin activity at both sites. r-Hirudin (0.3 heparin equivalent anti-IIa U/ml) was able to inhibit nearly all of the thrombin activity on each site. Each site was able to bind and express the activity of additional thrombin, indicating the potential for increased vessel thrombogenicity after local clot has formed and has been removed. These data indicate the presence of thrombin on dissected human vessels and its presence in equal amounts on intact and anastomosed vessels when measurement is made before blood flow resumes. Furthermore, vessel-associated thrombin is resistant to a standard systemic concentration of heparin but is susceptible to the much higher heparin concentration that can be delivered locally by the surgeon during vessel irrigation.

Probability of global indices in low tension glaucoma

To know the pattern of visual field (VF) defect of low tension glaucoma (LTG), its diffuse and localized VF defects were compared using the significance values (p-value) of mean deviation (MD) and corrected pattern standard deviation (CPSD), which are calculated with STATPAC in Humphrey Visual Field Analyser. Sixteen eyes of LTG were enrolled and 34 eyes of primary open angle glaucoma (POAG) were used as controls. The degree of VF defects in LTG and POAG was relatively mild with the p-value of MD equal to or greater than 1%. Neither mean MD nor mean CPSD of LTG was significantly different from each of POAG (p > 0.8 and p > 0.2, respectively). Comparing the p-values of MD and CPSD, many patients showed more significant p-value of MD in LTG and POAG (62.5% and 61.8%, respectively). However, relatively more severe defect of CPSD tended to occur more frequently in LTG than in POAG (25% and 5.9%, respectively, chi 2 = 4.964, p < 0.09). The relation between p-values of MD and CPSD was not significantly influenced by the intraocular pressure, MD or vertical cup to disc ratio in either LTG or POAG.

Immunomodulating effects of synchronised plasmapheresis and intravenous bolus cyclophosphamide in systemic lupus erythematosus

Recent studies have suggested that synchronised plasmapheresis and intravenous pulse cyclophosphamide therapy reduce disease activity in SLE patients. The aim of the present study was to examine the immunomodulating effects of this therapy and compare it with changes seen with cyclophosphamide alone. Four patients with active SLE were studied. Two were treated with synchronised therapy and two received cyclophosphamide only for up to 26 weeks. Disease activity was measured by the SLE disease activity index (SLEDAI). Immunological studies were performed immediately prior to each treatment. Patients in both treatment groups improved as reflected by a fall in mean SLEDAI scores: synchronised therapy 33.5 to 11; cyclophosphamide only 13.5 to 4.5. Following synchonised therapy only there was a prompt and sustained increase in the mean percentage of CD8+ cells (20.8 to 54.8) which resulted in a fall in the CD4:CD8 ratio (1.95 to 0.62). With both treatment modalities there was a fall in the proportion of CD20+ cells (B lymphocytes) (synchronised therapy 10.5 to 3.2; cyclophosphamide only 5.6 to 2.2). However, only synchronised therapy resulted in a fall in the in vitro production of immunoglobulins which was unchanged or increased following cyclophosphamide alone. These results suggest that although both treatment modalities are efficacious in the treatment of active SLE they produce different immunomodulatory effects. Thus, both therapies reduce the number of circulating B lymphocytes whereas synchronised therapy also modifies cellular immunity by promoting the emergence of a phenotypic suppressor T lymphocyte population.

Human cytomegalovirus (CMV) DNA in plasma reflects quantity of CMV DNA present in leukocytes

A quantitative DNA amplification assay for human cytomegalovirus (CMV) DNA has been used to evaluate the relationship between quantities of CMV DNA in plasma and those in infected leukocytes (WBC) from human immunodeficiency virus-infected patients. The target sequence for DNA amplification was a region of the immediate-early 1 gene of CMV. The quantitation assay uses an internal control that is coamplified with each patient sample DNA and contains a sequence for detection by colorimetric hybridization with the same bases, but in different order than in the CMV immediate-early 1 region used for hybridization of amplified patient sample DNA. Results showed that patients with CMV disease had more CMV DNA in both WBC and plasma than those without disease. However, in this study, copy numbers of CMV DNA in WBC were higher than those in plasma. The gB and gH variants were the same in plasma and WBC.

Characterisation of fast, slow and cardiac muscle tropomyosins from salmonid fish

Tropomyosin (TM) has been isolated from the cardiac muscle, and fast and slow trunk (myotomal) muscles of the mature salmonid fish Atlantic salmon (Salmo salar) and rainbow trout (Salmo gairdneri). When examined electrophoretically, isoforms of TM were detected which were specific, and exclusive, to each type of muscle. Cardiac and fast muscles contained single and distinct isoforms, while slow muscle contained two distinct isoforms, closely related in terms of apparent M(r), and pI. There was no detectable difference between the same TM type from either salmon or trout. On a variety of gel systems, the cardiac and slow isoforms migrated in close proximity to each other and to rabbit alpha-TM. The fast isoform comigrated with rabbit beta-TM. In developing salmon fry, a more acidic (unphosphorylated) variant of TM was present in addition to, and of similar M(r) to, the fast adult isoform. This TM declined in steady-state level during maturation and was virtually undetected in adult muscle. All of the isolated TMs contained little or no covalently bound phosphate and were blocked at the N-terminus. The amino acids released by carboxypeptidase A, when ordered to give maximal similarity to other muscle TMs, were consistent with the following sequences: fast (LDNALNDMTSI) and cardiac (LDHALNDMTSL). The C-terminal region of the slow TM contained His but was heterogeneous. In viscosity measurements, performed as a function of increasing protein concentration, at low ionic strength (t = 5 degrees C, pH 7.00), fast TM exhibited the highest relative viscosity values. Lower and equivalent levels of polymerisation occurred with the cardiac and slow TMs. Polymerisation of all three isoforms was temperature-dependent, with cardiac TM being least sensitive and fast TM being most sensitive. Determination of the complete coding sequence of adult fast TM confirmed the findings of the carboxypeptidase analysis, but the remainder of the sequence more closely resembled alpha-type TMs than beta-type TMs. Overall, salmon fast TM contains 20 (mostly conservative) substitutions compared to rabbit striated muscle alpha-TM and 40 (mostly conservative) substitutions compared to rabbit striated muscle beta-TM. This demonstrates that electrophoretic mobility is not, in all instances, a suitable method to assess the isomorphic nature of striated muscle TMs.

Variations in the vascular pedicle of the rat gracilis muscle flap

The rat gracilis muscle is a reliable model for microsurgical research. Exploration of 364 inguinal regions and preparation of 80 free gracilis muscle flaps in Sprague-Dawley and Lewis rats revealed six distinct origins of the dominant arterial pedicle and four variations of the venous pedicle. Popliteal, external iliac, and truncus pudendoepigastricus associations are described for the first time in this study. The total incidence of atypical variation of arterial pedicle origin is 20.7 percent. The most common origin of muscular branch arteries are the superficial epigastric artery (53.3 percent), femoral artery (22.0 percent), popliteal artery (14.6 percent), and the external iliac arteries (5.5 percent). Muscular branch veins drain most frequently into the femoral vein (79.1 percent). Gracilis muscle flaps prepared from rats weighing 329 +/- 45 g weighed an average of 0.64 +/- 0.13 g, and their volume averaged 0.87 +/- 0.12 ml. Muscular branch artery and vein diameters (external) averaged 0.21 +/- 0.05 mm and 0.54 +/- 0.06 mm, respectively. This new anatomic information is essential for reproducible microsurgery research using the rat gracilis muscle.

Requirement of beta 2 glycoprotein I as cofactor in the binding for IgM and IgA anticardiolipin antibodies

OBJECTIVE

To determine if IgM and IgA anticardiolipin (aCL) antibodies require beta 2 glycoprotein I (beta 2-GPI) as a cofactor for antibody binding.

METHODS

Sera were selected from 7 patients with systemic lupus erythematosus (SLE), 6 of whom had high IgM and 6 high IgA aCL antibody binding. Control sera were obtained from 2 healthy individuals with no aCL antibodies. Serum proteins were initially separated by sepharose CL6B get filtration chromatography, and IgM was further purified by affinity chromatography with mannan binding protein. IgA was isolated from CL6B filtrate by jacalin lectin affinity chromatography. Levels of beta 2-GPI in the immunoglobulin preparations were determined by antigen capture ELISA: Anticardiolipin antibody binding IgM and IgA was examined by ELISA with and without the addition of beta 2-GPI (10 micrograms/ml) or 4% normal human serum and expressed in optical density units (OD).

RESULTS

beta 2-GPI was required as a cofactor for IgM aCL antibody binding in 4 to 6 patients with SLE. In these, antibody binding to cardiolipin increased from (mean +/- SEM) 0.10 +/- 0.01 TO 1.06 +/- 0.22 (p = 0.005) with the addition of beta 2-GPI. For IgA, 5 of 6 patients with SLE demonstrated a requirement of beta 2-GPI as a cofactor. Antibody binding increased from 0.27 +/- 0.05 to 1.77 +/- 0.35 (p = 0.003) with the addition of beta 2-GPI.

CONCLUSION

beta 2-GPI is required as a cofactor for IgM and IgA aCL antibody binding.

A new photopolymerizable blood vessel glue that seals human vessel anastomoses without augmenting thrombogenicity

A new nonbiologic photopolymerizable glue, polyethyleneglycol 400 diacrylate, was studied with respect to its mechanical and biochemical interaction with human blood vessels. Using the human placental artery model, we tested the ability of polyethyleneglycol 400 diacrylate to prevent leakage of blood at the site of vascular anastomoses, which are made porous by the presence of tissue gaps and suture puncture sites. Fibrin glue is known to augment local vessel thrombogenicity through the presence of the coagulation enzyme thrombin. We tested the effect of externally applied polyethyleneglycol 400 diacrylate (which does not contain thrombin) on luminal thrombin activity and platelet deposition from flowing human blood. At a shear rate of 312 per second and a transmural pressure of 80 cm H2O, the leakage rate of saline from human placental artery anastomoses was 1.0 +/- 1.2 ml/min (n = 8). When the same anastomoses were then glued, 7 of 8 of the anastomoses leaked less than 0.05 ml/min (p < 0.05). Platelet deposition to human vessels was not influenced by the external application of polyethyleneglycol 400 diacrylate either on intact vessels (no polyethyleneglycol 400 diacrylate, 0.51 +/- 0.28 x 10(6) platelets/cm2; with polyethyleneglycol 400 diacrylate, 0.47 +/- 0.26 x 10(6) platelets/cm2; n = 7) or at anastomoses (no polyethyleneglycol 400 diacrylate, 0.69 +/- 0.36 x 10(6) platelets/cm2; with polyethyleneglycol 400 diacrylate, 0.53 +/- 0.33 x 10(6) platelets/cm2; n = 8), p > 0.05.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of adrenergic agonists on the growth and gene expression of the transplanted heart

Cardiac growth occurs in response to changes in hemodynamic demand and results primarily from cellular hypertrophy without cellular hyperplasia. In addition to changes in cardiac work, various reports have demonstrated that adrenergic stimulation, specifically of the alpha 1 adrenergic receptor of cultured myocytes, can produce changes in cardiac-specific gene expression and increases in protein synthesis and cell growth. To study the effects of adrenergic stimulation in the absence of alterations in cardiac work we have used the model of the heterotopically transplanted heart, which is a spontaneously beating, vascularly perfused, and histologically normal heart that is hemodynamically unloaded. Seventy-two hours after transplantation, the hemodynamically unloaded transplanted heart had decreased in size by 20% when compared with the control host heart that was growing in situ. Treatment with either the alpha-adrenergic agonist phenylephrine (2.5 mg/kg/day) or the beta-adrenergic agonist isoproterenol (250 micrograms/kg/day) while increasing the spontaneous heart rate had no effect on the size of the transplanted heart. Simultaneous measurements demonstrated that both of these drugs produced a 10% increase in weight of the corresponding hemodynamically loaded host heart. We previously demonstrated that cardiac unloading caused a change in the expression of the myosin heavy chain (MHC) genes with a significant increase in the beta MHC isoform. In the present studies treatment with either isoproterenol or phenylephrine did not alter MHC gene expression either in the in situ host or transplanted hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of postoperative mitomycin C on glaucoma filtration surgery in rabbits treated preoperatively with antiglaucoma medications

In a rabbit model, we evaluated the effects of topically applied postoperative mitomycin C (MMC) on the success rate of glaucoma filtration surgery in animals treated preoperatively with pilocarpine hydrochloride 4% and levobunolol hydrochloride (Betagan) for 16 weeks. Full-thickness filtration surgery was performed with a single 5-minute intraoperative exposure to a sponge soaked with 0.4 mg/mL MMC of one eye in nine rabbits in one group (group A) and to both eyes in 13 rabbits in a second group (group B). In addition, one eye of each rabbit in group B received a daily drop of 0.4 mg/mL MMC for 13 days after the operation. All of the eyes were then followed for 80 days. The intraoperatively applied MMC enhanced the success rate of the filtration surgery in the group A eyes. However, the eyes that also received postoperative drops of MMC (group B) had longer periods of reduced intraocular pressure (IOP) (P [chi-squared = 5.94] < .025), fewer bleb failures (P [chi-squared = 8.09] < .005), and more complications than the eyes that received only intraoperative MMC.

Detection of anthelmintic resistant nematodes in sheep in southern England by a faecal egg count reduction test

On five farms identified by in vitro tests to have benzimidazole resistance, and on one farm with apparent anthelmintic failure, faecal egg count reduction tests were performed using benzimidazoles, levamisole and ivermectin. With benzimidazoles efficacy was less than 70 per cent on all farms, confirming the validity of the in vitro tests to detect benzimidazole resistance. On two farms levamisole had an efficacy of less than 90 per cent but laboratory tests failed to demonstrate levamisole resistance. Ivermectin reduced egg counts by 100 per cent on all farms.

The effects of intraoperative mitomycin-C or 5-fluorouracil on glaucoma filtering surgery

We compared the success rate of filtering surgery of a single 5-minute intraoperative application of mitomycin-C (MMC) or 5-fluorouracil (5-FU). Animal experiment and clinical study were done. In animal study, thirty pigmented rabbits (60 eyes) weighing 2.0 to 2.5 Kg were enrolled. We divided into 4 groups, such as BSS, 5-FU 50 mg/ml, MMC 0.2 mg/ml and MMC 0.4 mg/ml subconjunctival soaked group. Each group consisted of 15 eyes. In each group, 10 eyes was for examination of bleb survival and complications, 3 eyes for light microscopic examination and 2 eyes for electron microscopic examination. Bleb was survived 6.1 days (3 to 13 days) for BSS treated group, 16.3 days (9 to 23 days) for 5-FU 50mg/ml treated group, 32.7 days (17 to 55 days) in MMC 0.2 mg/ml treated group, and 64.4 days (49 to 84 days) in MMC 0.4 mg/ml treated group. Duration of bleb survival was significantly prolonged in 5-FU, MMC 0.2 mg/ml and MMC 0.4 mg/ml group respectively. In clinical study, fifty-five eyes of 40 patients were enrolled. 29 eyes of 21 patients were treated with MMC 0.2 mg/ml and 26 eyes of 19 patients were treated with 5-FU 50 mg/ml. The success rate was 89.7% in MMC 0.2 mg/ml treated group and 84.6% in 5-FU 50 mg/ml treated group at postoperative 3 months, and postoperative 6 months 89.7% in MMC 0.2 mg/ml treated group and 76.9% in 5-FU 50 mg/ml treated group. There was no statistical significance at postoperative 3 months (P > 0.05), but statistical significance at postoperative 6 months (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation and characterization of tropomyosin from fish muscle

A comprehensive survey of tropomyosin from various fish myotomal muscles is reported. The fish tropomyosins were blocked at the N-terminus and, as expected, were found to be of similar amino acid composition, alpha-helical content (> 90% at 10 degrees C) and molecular weight to other vertebrate striated muscle forms. The tropomyosins of salmonids and herring muscle were noticeably heterogeneous when assessed by 2D-PAGE. The distribution of isoforms was tissue-specific: slow muscle contained alpha-type tropomyosin while fast muscle contained beta-type tropomyosin. In other species (cod, haddock, wolf-fish and sharks) alpha-type tropomyosins were present in both kinds of muscle but beta-tropomyosin was absent.