Intradermal injection of methylene blue for the treatment of refractory pruritus ani

OBJECTIVE

Idiopathic pruritus ani is a common perianal condition that can be refractory to diligent perineal care. We wished to evaluate the efficacy and side effects of intradermal methylene blue for the treatment of refractory pruritus ani.

METHOD

A prospective series of 49 patients with idiopathic pruritus ani, who had failed to improve with perineal care, were treated by a single surgeon. All patients received intradermal injections of methylene blue. Endpoints were patient symptom score, and complications (pain, dysaesthesia, skin necrosis, incontinence and anaphylaxis).

RESULTS

Symptoms improved in 96% and resolved in 57% of patients after one treatment. All four patients who had a second treatment became symptom-free. Seven patients noticed changes in continence, all resolved between 10 days and 6 weeks. Two patients were distressed by their decrease in their perianal sensation. There was no skin necrosis or anaphylaxis.

CONCLUSION

Treatment of refractory pruritus ani by intradermal injection of methylene blue is effective and generally well tolerated.

Bacillus cereus is common in the environment but emetic toxin producing isolates are rare

AIMS

To determine the incidence of emetic toxin producing Bacillus cereus in soil, animal faeces and selected vegetable produce to compare the results with the previously reported high incidence in rice paddy fields. To examine whether the emetic toxin has antibiotic activity.

METHODS AND RESULTS

The incidence of emetic toxin producing B. cereus was evaluated by plating on selective agar 271 samples of soils, animal faeces, raw and processed vegetables. Overall, 45.8% of samples were positive for B. cereus. One hundred and seventy-seven B. cereus isolates were recovered at 30 degrees C with the grand mean spore count being 2.6 +/- 1.7 log(10) CFU g(-1) and 148 B. cereus isolates were recovered at 7 degrees C with the grand mean spore count being 2.2 +/- 1.2 log(10) CFU g(-1) of the 177 B. cereus isolated at 30 degrees C, only 3 were positive for emetic toxin production at a titre of 1/64, 1/32, 1/16, respectively. Also, 1 of 148 B. cereus isolated at 7 degrees C was positive for emetic toxin production to a titre of 1/128. All positive isolates came from washed or unwashed potato skins, one was psychrotrophic as determined by PCR and growth at 7 degrees C on subculture. The emetic toxin was not shown to have any antibiotic effects in growth inhibition studies.

CONCLUSIONS

While B. cereus was a common isolate, the incidence of the emetic strain was rare. This is in contrast to previous findings of the high incidence in rice paddy fields and the processing environment, which may suggest rice is a selective area for growth of the emetic strain of B. cereus.

SIGNIFICANCE AND IMPACT OF STUDY

The finding that a psychrotrophic isolate of B. cereus can produce emetic toxin is the first ever such observation and suggests the possibility that psychrotrophic isolates could grow in refrigerated fresh foods and cause emesis. The incidence of emetic B. cereus strains in rice paddy fields now requires further study for comparison with the low incidence found in other soils. The emetic toxin failed to inhibit the growth of other bacterial, fungal and yeast species. Whether the toxin (which is similar in structure to the antibiotic valinomycin) plays a competitive role in the environment therefore remains unclear.

Bacillus cereus produces most emetic toxin at lower temperatures

Seven emetic toxin-producing strains of Bacillus cereus were examined for toxin production in Skim Milk Medium at incubation temperatures ranging from 10 to 50 degrees C. Minimum and maximum growth temperatures were found to be 12 and 46 degrees C, respectively. At 12 and 15 degrees C, levels of toxin production were significantly higher (P < 0.01) than that observed at 30 degrees C, while no toxin was produced above 37 degrees C. Increased levels of sporulation were observed at increased temperatures, and no correlation was found between levels of sporulation and toxin production (R(2) = 0.086).

Semiautomated metabolic staining assay for Bacillus cereus emetic toxin

This paper describes a specific, sensitive, semiautomated, and quantitative Hep-2 cell culture-based 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay for Bacillus cereus emetic toxin. Of nine Bacillus, Brevibacillus, and Paenibacillus species assessed for emetic toxin production, only B. cereus was cytotoxic.

Total 24-hour melatonin secretion in adolescent idiopathic scoliosis. A case-control study

STUDY DESIGN

A case-control study of 24-hour urinary melatonin production in patients with adolescent idiopathic scoliosis.

OBJECTIVES

To address the controversy over the role of melatonin deficiency in adolescent idiopathic scoliosis by measuring total melatonin production over a 24-hour period.

SUMMARY OF BACKGROUND DATA

An association between melatonin deficiency and experimental scoliosis has been suggested in several animal species. Recent work has failed to show a deficiency in humans with scoliosis. However, this conclusion was based on single urinary estimations. In this study the period assayed was standardized to 24-hours for all patients to include the full diurnal cycle of melatonin excretion.

METHODS

Consecutive patients at an outpatient clinic for adolescent idiopathic scoliosis were recruited as subjects for this study, and patients from a fracture clinic who were of similar age and gender were recruited as controls at their final follow-up examination after the healing of their fracture. Patients and control individuals collected urine over a 24-hour period that was divided into consecutive day and night collections of 12 hours each. Total urinary excretion of 6-sulphatoxy melatonin was determined by radioimmunoassay for each 12-hour period in patients and control individuals.

RESULTS

No significant difference in diurnal, nocturnal, or total urine 6-sulphatoxy melatonin excretion was found between adolescent patients with idiopathic scoliosis and controls of similar age and gender. There was also no difference between the two groups when 6-sulphatoxy melatonin excretion was corrected for body weight, body surface area, and body mass index. Nor was there a significant difference between 6-sulphatoxy melatonin excretion of patients with scoliosis whose curves failed to progress over the course of a year and the excretion of those who underwent surgery.

CONCLUSIONS

In adolescent idiopathic scoliosis, neither the presentation with a stable spinal deformity, nor presentation with a severe deformity requiring surgery is associated with melatonin deficiency.

Temperature characterization of psychrotrophic and mesophilic Bacillus species from milk

A total of 50 isolates of Bacillus spp. and one reference strain were investigated for their growth at 6.5 degrees C for 10 d, 30 degrees C for 3 d and 40 degrees C for 2 d. The results obtained differentiated three physiological groups: one clearly psychrotrophic (able to grow at 6.5 degrees C in 10 d, but not at 40 degrees C in 2 d), one intermediate in psychrotrophy (it grew at both 40 and 6.5 degrees C) and one mesophilic (capable of growth at 30 and 40 degrees C, but not at 6.5 degrees C). The proportion of strains in the second group was higher among isolates of B. cereus than for other Bacillus spp. However, the proportion of real mesophilic strains was lower for B. cereus isolates. Psychrotrophic B. cereus grew better at both 6.5 and 30 degrees C than other psychrotrophic Bacillus spp. Using eight strains, a correlation between differential growth at mesophilic temperatures (count at 30 degrees C minus count at 40 degrees C) and a standard psychrotrophic count at 6.5 degrees C for 10 d (r = 0.95) was obtained in mixed cultures when the psychrotrophic flora count was < or = 1 log (cfu/ml) lower than the mesophilic count.

Spinal fusion in Duchenne's muscular dystrophy

The Women's and Children's Hospital experience with Luque spinal fusion in Duchenne's muscular dystrophy was reviewed from its commencement in 1983 to the present with a view to assessing the clinical and radiologic outcome and safety of the procedure. Seventeen boys have undergone spinal fusion. L-rod instrumentation was used in 10, six of whom had significant problems with sitting imbalance or progression of the scoliosis or both. In seven cases, distal instrumentation was taken to the pelvis with a Galveston construct and rigid crosslinking. Apart from some progression and sitting imbalance in the L-rod group, there were few complications. In the Galveston group, pelvic obliquity was corrected by a mean of 63%, and there was better maintenance of correction. There were no pseudoarthroses or instrument failures in the Galveston group. Of the total group, four patients had forced vital capacity (FVC) values < 25% predicted, and two required ventilation postoperative (< 48 h). There were no other respiratory complications. The effect of surgery on respiratory function remains uncertain. Spinal fusion with the Luque rod construct and pelvic fixation is a safe procedure. It provided a mean correction of 60% and control of pelvic obliquity without significant postoperative deterioration. In our experience, surgery can be safely performed with FVC value down to 20% predicted. On the basis of these data, one current practice is to instrument to the pelvis with a Galveston construct and Texas Scottish Rite Hospital cross-linking.

Effect of spinal surgery on lung function in Duchenne muscular dystrophy

BACKGROUND

The effect on subsequent respiratory function of spinal stabilisation for scoliosis in Duchenne muscular dystrophy is unclear. In order to clarify this clinical problem, changes in the forced vital capacity of a group of children with Duchenne muscular dystrophy who had undergone spinal surgery were measured and compared with a group of children with Duchenne muscular dystrophy who had not had surgery.

METHODS

In this retrospective study 17 boys with Duchenne muscular dystrophy who underwent spinal stabilisation at a mean age of 14.9 years (surgical group) were compared with 21 boys with Duchenne muscular dystrophy who had not had surgery (non-surgical group). The mean (SD) Cobb angle of the surgical group at 14.9 years was 57 (16.4) degrees, and of the non-surgical group at 15 years was 45 (29.9) degrees. Forced vital capacity expressed as percentage predicted (% FVC) was measured in total over a seven year period in the surgical group and over 6.5 years in the non-surgical group, and regression equations were calculated. Survival curves for both groups were also constructed.

RESULTS

No difference was found between spinal stabilisation (surgical group) and the non-surgical group in the rate of deterioration of % FVC which was 3-5% per year. There was no difference in survival in either group.

CONCLUSIONS

Spinal stabilisation in Duchenne muscular dystrophy does not alter the decline in pulmonary function, nor does it improve survival.

Seasonal occurrence of psychrotrophic Bacillus species in raw milk, and studies on the interactions with mesophilic Bacillus sp

Mesophilic and psychrotrophic isolates of Bacillus species displayed seasonal incidences in raw and pasteurised milk. The incidence of mesophilic isolates was highest in the winter and lowest in the summer/autumn while pschrotroph incidence was conversely lowest in the winter and highest in the late summer/autumn. Spores of Bacillus sp. were isolated from raw milk taken from farm milk machines and bulk tanks, milk tankers, diary silos and pasteurised milk. A consistent seasonal fluctuation in incidence throughout these samples suggested that spores of Bacillus sp. derived from the farm environment survived as important contaminants right through the milk chain to the pasteurised product. Up to seven mesophilic Bacillus sp. were isolated from a single sample with three species commonly occurring in most samples. The predominant mesophilic species isolated were B. pumilus, B. licheniformis and B. subtilis. The dominant psychrotrophic isolate was B. cereus. Selected mesophilic isolates were examined for possible antagonistic effects on the growth of psychrotropic B. cereus and B. pumilus isolates. Bacillus subtilis and B. licheniformis were found to produce antagonistic factors. It was considered that these factors may influence the incidence and growth of psychrotrophic isolates in the farm environment or in milk but the factors are not yet fully characterised or identified.

Phenotypic analysis of lymphocytes obtained by bronchoalveolar lavage of normal sheep

Lungs were excised from apparently healthy sheep at slaughter and lymphocytes obtained by bronchoalveolar lavage were separated by buoyant density and characterised phenotypically. In most animals T-lymphocytes (CD5+ cells) accounted for almost the entire population, with B-lymphocytes (sIg+ cells) generally accounting for less than 10%. In the main, CD4+ T cells exceeded CD8+ T cells by at least a factor of three and CD4-/CD8- (gamma delta) T cells represented around 6% of the population. Proportions of subtypes of lymphocytes obtained by bronchoalveolar lavage differed from those in peripheral blood. The normal range of lymphocyte phenotypes in the ovine lung established in this study will be of value in subsequent work on animals with defined respiratory disease.

Toxin production by Bacillus cereus in dairy products

Spores of a known toxigenic and psychrotrophic dairy isolate of Bacillus cereus (HRM 44) were unable to grow and produce diarrhoeagenic toxin at 6 degrees C in creams and dairy-based products. These findings suggest that the production of B. cereus diarrhoeagenic toxin is unlikely to occur in creams and dairy-based products maintained within the cold chain. Growth and toxin production were readily demonstrated in creams and some desserts stored at 21 degrees C. Growth in creams was associated with obvious spoilage. However, in the flavoured desserts, spoilage was not always obvious before significant growth of B. cereus and toxin production had occurred. Dairy desserts with high sugar content and/or low pH did not support toxin production and these findings are discussed.

Influence of pH and sugars on the growth and production of diarrhoeagenic toxin by Bacillus cereus

Broth cultures supplemented with high levels of sugars, particularly glucose at > 50 milligrams, did not support diarrhoeagenic toxin production by psychrotrophic Bacillus cereus despite growth to high counts (approximately 10(7)/ml) over a 4 d period of incubation at 21 degrees C. In contrast, starch levels of 10 and 50 milligrams actually enhanced toxin production. Toxin production was also affected by pH levels of broth cultures, and was concomitant with alterations in bacterial growth. These findings help to explain variations in toxin levels previously found in some dairy desserts, which were thought to be associated with pH and sugar content (Sutherland, 1993).

Effect of heat treatment on Listeria monocytogenes and gram-negative bacteria in sheep, cow and goat milks

Sheep milk, compared with cow and goat milk, had a protective effect on Gram-negative bacteria and Listeria spp. heated at 65 degrees C in a test-tube method. This effect was not solely due to fat content as cow milk artificially reconstituted to 10% homologous fat was not as protective. Listeria monocytogenes in whole sheep, cow and goat milks at an inoculum level of 1 x 10(6) cfu ml-1 was heated at 68 degrees C for 15 s in the plate pasteurizer and survival was only detected in whole sheep milk after heating. Whole sheep, cow and goat milks containing high levels of L. monocytogenes (1 x 10(6) cfu ml-1) could not survive the current HTST plate pasteurization protocol.

An experimental anti-idiotype vaccine mimicking lipopolysaccharide gives protection against Pasteurella multocida type A infection in mice

An anti-idiotype strategy was employed which showed that polyclonal anti-idiotype antibodies could be produced which could mimic a linear Pasteurella multocida lipopolysaccharide (LPS) molecule. These antibodies when used as vaccine antigens, induced antibodies which recognised LPS and imparted acquired protection upon syngeneic vaccinates challenged with homologous organisms.

Characterisation and biological activity of monoclonal antibodies specific for Pasteurella haemolytica A1 capsule and lipopolysaccharide

Monoclonal antibodies (mAb) against both Pasteurella haemolytica A1 capsule and lipopolysaccharide (LPS) were produced. Anti-capsule mAb reacted with the homologous A1 serotype only, whereas mAb against LPS reacted with P. haemolytica serotypes A2, A5, A8, A12, A14 and A16 but not with 33 bacterial species or rough LPS mutant strains tested. Both capsule and LPS antigens were visualised on the surface of bacteria by immunogold electron microscopy. Neither of the mAbs demonstrated antibody-dependent complement-mediated killing in vitro but both facilitated phagocytosis in vitro.

Occurrence and diversity of plasmids in ovine isolates of Pasteurella haemolytica

160 ovine isolates of Pasteurella haemolytica, representing each of the 16 serotypes and also untypable strains, were examined for plasmid content. Plasmid DNA was identified in, and prepared from, strains of serotypes A2, T3, A14 and A16 and also from an untypable strain. The relationship between the plasmids present in the different strains was examined both by restriction fragment profile analysis and by DNA/DNA hybridisation. Both methods gave broadly similar results and showed that each serotype tended to contain either a single plasmid species, or a limited range of species, and that structural similarities could traverse serotype boundaries. None of the plasmid-bearing strains showed any significant level of resistance to a range of antibiotics.

Identification and localization of an iron-regulated 35 kDa protein of Pasteurella haemolytica serotype A2

Iodination of intact Pasteurella haemolytica serotype A2 cells labelled a sub-set of total cellular proteins. Comparison of the autoradiographic patterns obtained from iodinated cells grown on complete medium and on iron-depleted medium showed that expression of three proteins, of 100, 70 and 35 kDa, respectively, was increased by growth under iron-depleted conditions. Of these proteins, that of 35 kDa had not been reported previously. Like the 100 and 70 kDa proteins, the 35 kDa protein was expressed in natural infections, since it was recognized by antiserum from sheep that had recovered from an experimental infection with P. haemolytica A2. The 35 kDa protein was partially purified by reverse-phase HPLC and was found to be antigenic in both sheep and mice. A monoclonal antibody that was specific for the 35 kDa protein was used to identify the cellular location of the protein by immunoblotting of cell fractions enriched for particular cellular components. This demonstrated that the 35 kDa protein was located mainly in the periplasm.

Vaccine containing iron-regulated proteins of Pasteurella haemolytica A2 enhances protection against experimental pasteurellosis in lambs

A vaccine containing sodium salicylate extract (SSE) of Pasteurella haemolytica A2 cells grown in a medium chemically depleted of available iron by the addition of alpha alpha dipyridyl to induce iron-regulated proteins (IRPs) conferred protection to specific pathogen-free (SPF) lambs exposed to an aerosol of P. haemolytica A2. The disease score in these lambs was significantly lower (p less than 0.005) than those in unvaccinated lambs or in lambs immunized with SSE prepared from cells grown in iron-replete medium. Immunoblotting of sera from these SPF lambs against whole cell antigens of P. haemolytica A2 grown under iron-restricted conditions demonstrated that antibodies to IRPs were present only in the sera of animals immunized with SSE-IRP. The antibody profile of sera from the SSE-IRP group was similar to that obtained with serum from a lamb which had recovered from P. haemolytica A2 disease produced experimentally. Negligible levels of cytotoxin-neutralizing and bactericidal antibodies were detectable in the SSE-IRP group and therefore appear not to be involved in the protection observed in this experiment.

The susceptibility of in vivo-grown Pasteurella haemolytica to ovine defence mechanisms in vitro

Pasteurella haemolytica organisms grown in vivo were examined for their susceptibility to ovine immune mechanisms in vitro. Compared with in vitro grown organisms they were less susceptible to opsonophagocytosis and, in contrast, susceptible to complement-dependent killing in the absence of exogenous antibody. These differences were not associated with phenotypic changes in the surface of the bacterial cell. However, overproduction and de novo synthesis of proteins was observed in in vivo grown organisms. Also, bound host-immunoglobulin was observed on in vivo grown organisms and a role for this in modifying the interaction with immune mechanisms is discussed.

Bactericidal activity in the sera of mice vaccinated with Pasteurella multocida type A

The susceptibility of Pasteurella multocida to killing by serum and the ability of protective vaccines to stimulate this mechanism of immunity in mice were investigated. P. multocida type of bovine origin was used to prepare a vaccine incorporating heat killed organisms and for homologous infection of mice. Bactericidal capacity and ELISA antibody titres were determined for individual mouse sera. Protection was clearly associated with bactericidal antibodies raised by vaccination. The bactericidal assay may be useful as a rapid, simple screening test of vaccinated mice for functional protective antibody levels.

Cotrel-Dubousset instrumentation and vertebral rotation in adolescent idiopathic scoliosis

We have studied 34 consecutive patients receiving Cotrel- Dubousset instrumentation for a single and flexible thoracic scoliotic curve, evaluating the rib hump deformity from a single CT scan through the apical vertebra of the curve. Using two measures of rotation we found a mean improvement of 25% in the rotation of the vertebra after operation. Any, usually minor, deterioration occurred in the first six months postoperatively, and there was no significant further deterioration in 19 patients assessed over two years after surgery. Cotrel-Dubousset instrumentation can produce a significant correction of vertebral rotation and of the associated rib hump deformity.

A colourimetric, microplate assay for the leucotoxin of Pasteurella haemolytica

Culture supernates of Pasteurella haemolytica, which contain leucotoxin, inhibited the reduction of nitroblue tetrazolium (NBT) by bovine and ovine but not rabbit leucocytes in response to phorbol 12-myristate 13-acetate (PMA). Culture supernates of P. multocida, which contain no leucotoxin, had no inhibitory effect on the response of leucocytes from any species. The inhibition of NBT reduction was assessed visually or spectrophotometrically in the wells of microplates and used as a simple assay for leucotoxin. It was as sensitive as the trypan blue dye-exclusion method and did not require the use of radioisotopes. In addition, sera from P. haemolytica-infected calves inhibited leucotoxin activity in the microplate assay. Thus, inhibition of NBT reduction after stimulation of ruminant leucocytes with PMA can be used as a simple, specific assay for leucotoxin and for anti-leucotoxin antibodies.

Protection of lambs against experimental pneumonic pasteurellosis by transfer of immune serum

Passive protection of specific pathogen-free lambs against experimental pasteurellosis was achieved using antisera from conventionally reared sheep which were either convalescent from experimental pneumonia or inoculated with Pasteurella haemolytica A2 vaccines. The complete immune sera, or immunoglobulin-rich fractions prepared from them, when administered separately or together provided 94-100% protection of recipients compared to control lambs. Antibodies to P. haemolytica in donor sera were quantified by anti-sodium salicylate extract (SSE) and anti-lipopolysaccharide (LPS) ELISA, bactericidal assay, cytotoxin neutralization and indirect haemagglutination. The anti-SSE ELISA titres correlated best with protective efficacy and could be used to measure antibody in recipient lambs immediately before challenge. The degree of protection was unaffected by prior infection with parainfluenza virus Type 3, suggesting that such exposure did not enhance exudation of circulating immunoglobulin into the respiratory tract. It was concluded that systemic humoral immunity alone can prevent pasteurellosis.

A crude cytotoxin vaccine protects sheep against experimental Pasteurella haemolytica serotype A2 infection

Three vaccines containing Pasteurella haemolytica serotype A2 antigens were tested for their ability to protect sheep against a homologous challenge. A crude cytotoxin preparation in combination with a sodium salicylate extract (SSE) or crude cytotoxin alone were highly protective (98 and 86%, respectively), whereas SSE alone was poorly (47%) protective. These findings indicated that the crude cytotoxin was an essential component of a protective vaccine. Protection correlated with serum cytotoxin-neutralising (CN) titres and bactericidal activity, which were stimulated by antigens in the crude cytotoxin preparation.

A rapid micro-method for the study of antibody-mediated killing of bacteria, with specific application to infection of sheep with Pasteurella haemolytica

A micro-titration plate bactericidal assay was developed to measure complement-dependent antibody-mediated killing of Pasteurella haemolytica. Sera and lung washings from specific pathogen-free (SPF) lambs convalescent from a challenge with live, virulent P. haemolytica were bactericidal in the presence of complement. Similar samples from naive SPF lambs had no such activity. Purified IgG derived from a convalescent lamb serum was as bactericidal as the whole serum. Absorption of convalescent serum with lipopolysaccharide from P. haemolytica abolished bactericidal activity, suggesting that this antigen may be a target for antibody in the bactericidal complex.

Subacute pulmonary melioidosis in a temperate climate

Previous reports of cases of melioidosis that were seen in nonendemic areas of Australia describe recrudescences of latent infection. We describe the case of a patient who presented in the cooler climate of Melbourne with a probable primary, subacute pulmonary infection with Pseudomonas pseudomallei. This case illustrates several points that bear consideration in the management of atypical pneumonia and, more specifically, pulmonary melioidosis. Historical and occupational clues are easily missed or unrecognized, while a persistent growth of gentamicin-resistant Pseudomonas species should arouse suspicion. Septicaemic melioidosis carries a poor prognosis, and treatment should be early and aggressive; use of the newer, third-generation cephalosporin agents should be considered. Given active support in a well-equipped intensive care unit, together with appropriate antibiotic therapy, patients may eventually be cured of this infection, but a high mortality rate is still encountered.

The effect of preoperative oral fluid and ranitidine on gastric fluid volume and pH

One hundred unpremedicated daycare patients were randomly assigned to one of four groups. Between two and three hours preoperatively all patients received either oral ranitidine 150 mg, or placebo, with bromosulphthalein (BSP) 50 mg in 10 ml water, immediately followed by either 150 ml water or no further fluid. The residual gastric volume (RGV) in the two placebo groups was significantly lower in patients given 150 ml water (20.6 +/- 14.1 ml) than in those who continued fasting (29.9 +/- 18.2 ml) (p less than 0.05). The RGV was further significantly decreased in the two ranitidine groups (10.0 +/- 8.8, 9.7 +/- 10.5 ml) compared with the two placebo groups (20.6 +/- 14.1, 29.9 +/- 18.9 ml) (p less than 0.01). Mean pH values were significantly higher in the two ranitidine groups (6.71 +/- 0.99; 6.31 +/- 1.81) than in the two placebo groups (2.05 +/- 1.41; 1.72 +/- 0.33) but were not significantly different in the fluid versus non-fluid groups. In patients who ingested 150 ml water there was no correlation between the premedication interval and either RGV or pH values. The extremely low percentage of the original BSP (less than 0.9 per cent) in the gastric fluid of these patients demonstrated that gastric emptying of the ingested water was virtually complete prior to surgery. The combination of RGV of 25 ml or more with pH less than 2.5 was present in 56 per cent of patients who had only a sip of water with placebo, in 28 per cent of those who received 150 ml water with placebo, and in only two per cent of those patients who received ranitidine.

Preoperative oral fluids: is a five-hour fast justified prior to elective surgery?

The effects of preoperative oral administration of 150 ml fluid were studied prospectively in 140 unpremedicated, ambulatory outpatients presenting for first trimester therapeutic abortion. Intraoperative gastric fluid volume, pH, and rate of gastric emptying were measured in the four groups to which patients were randomly assigned. At an average time of 2 1/2 hr preoperatively all patients received either oral ranitidine, 150 mg, or a placebo tablet, with the nonabsorbable marker dye bromosulphthalein (BSP, 50 mg in 10 ml water, followed by either 150 ml water or no further fluid. The effect of volume ingested was assessed by comparing the volume of gastric contents obtained by gastric tube suctioning at the completion of surgery in the two groups given placebos. The gastric volume was significantly less in patients given 150 ml water (17.6 +/- 14.5) than in those given only BSP (26.7 +/- 18.9) (P less than 0.02), and was further significantly decreased in the two groups given ranitidine (8.3 +/- 7.3, 9.5 +/- 7.7 ml) (P less than 0.001). Mean pH values were significantly higher in the two ranitidine groups (5.52 +/- 1.79, 5.03 +/- 1.79) than in the two placebo groups (1.75 +/- 0.94, 1.92 +/- 1.27). The combination of a residual volume of 25 ml and pH less than 2.5 was found in 46% of patients given only BSP with placebo, in 23% of those given 150 ml water with placebo, and in no patient given ranitidine. There was no correlation between the gastric volume or pH values with the ingestion-surgery interval in patients given 150 ml water.

Effects of preoperative fasting on morbidity and gastric contents in patients undergoing day-stay surgery

The effects of overnight fasting on gastric contents and on the symptoms associated with fasting were studied prospectively in female outpatients. Group A (n = 66) were patients scheduled for first trimester therapeutic abortion; group B (n = 66) were scheduled for minor gynaecological surgery. It was demonstrated that overnight fasting (15 +/- 3 h) did not guarantee an empty stomach (volume 22 +/- 13 ml) and that gastric acidity was high (pH 1.6 +/- 0.5). Gastric volumes and pH were the same in both groups. Group A patients had a higher incidence of preoperative nausea and vomiting (P less than 0.001). Before anaesthesia, 50% of all patients had symptoms of moderate to severe hunger, while 44% of patients had symptoms of moderate to severe thirst. Neither the severity of symptoms of fasting nor the duration of fast correlated with gastric volume or pH. Patients in group A had significantly greater symptoms of hunger; however, they also had fasted for significantly longer (P less than 0.002).

Fibreoptic awake intubation--a method of topical anaesthesia and orotracheal intubation

Three cases of trismus caused by oropharyngeal sepsis are described where fibreoptic-assisted awake intubation using an oral airway intubator and nebulised lidocaine was safely and successfully achieved.

Cytotoxin from an ovine strain of Pasteurella haemolytica: characterisation studies and partial purification

A cell-free, water-soluble cytotoxin from an ovine strain of Pasteurella haemolytica biotype A serotype 1 killed sheep bronchoalveolar macrophages at 37 degrees C, but not at 4 degrees C or 22 degrees C. The cytotoxin was stable over the pH range 2-12, resistant to heat at 60 degrees C but inactivated at 100 degrees C or by autoclaving. Trypsin also destroyed the cytotoxin, which is therefore thought to contain a protein component essential for biological activity. A preliminary purification of the crude cytotoxin using gel-filtration column chromatography resulted in the isolation of a biologically active fraction which resolved as a single protein band and one carbohydrate band on non-dissociating polyacrylamide gels. However, this fraction resolved into approximately 16 component bands on a sodium dodecyl sulphate polyacrylamide gel.

Cardiovascular responses and lidocaine absorption in fiberoptic-assisted awake intubation

Local anesthetic toxicity and cardiovascular stress during fiberoptic-assisted awake tracheal intubation were assessed prospectively in 20 patients with airway management problems. Cardiovascular responses, dose of lidocaine, its systemic absorption, and patient comfort were measured. A standardized topical anesthesia protocol of 4% lidocaine aerosol, topical 2% lidocaine viscous gel, and direct perbronchoscopic laryngeal application was used. Awake intubation produced no significant elevation of blood pressure or pulse rate either during the topical application or after the intubation. Despite a large total dose of topical lidocaine (5.3 +/- 2.1 mg/kg), the mean peak arterial plasma lidocaine concentration was low (0.6 +/- 2.1 micrograms/ml). Patient comfort assessment showed that nine patients had no discomfort, whereas 11 had minimal discomfort. Supplementary sedation used was minimal (fentanyl, 1.4 +/- 0.6 micrograms/kg, and diazepam, 1.9 +/- 1.8 mg). This method of producing topical anesthesia for awake tracheal intubation is recommended as a safe, easy, and comfortable method of managing patients with airway difficulties.

Cytotoxic effect of serotypes of Pasteurella haemolytica on sheep bronchoalveolar macrophages

Ovine isolates of the 15 known serotypes found within the A and T biotypes of Pasteurella haemolytica were cytotoxic for sheep bronchoalveolar macrophages (BAM). Weaker toxicity for the same target cells was also expressed by non-serotypable ovine isolates of P. haemolytica. The results suggest that cytotoxicity for sheep BAM is a virulence factor common to both A and T biotypes of P. haemolytica.

Immunity of specific pathogen-free lambs to challenge with an aerosol of Pasteurella haemolytica biotype A serotype 2. Pulmonary antibody and cell responses to primary and secondary infections

Specific pathogen-free (SPF) lambs previously exposed to an aerosol of P. haemolytica biotype A serotype 2 (A2) were immune to subsequent challenge with an aerosol of P. haemolytica A2. Untreated control lambs were not immune to this challenge. The local immune responses of the lung to these challenges were examined. High IgG and IgA titres to P. haemolytica and high levels of opsonizing antibody against P. haemolytica were present in the lung washings from previously infected immune lambs at autopsy, seven days after the second infection. Lung washings from control lambs, 7 days after challenge with P13 virus and P. haemolytica A2, had no IgG titres, very little opsonizing activity but did have IgA titres which were significantly higher than in unchallenged control lambs. The cellular response of animals challenged with P13 virus and P. haemolytica was significantly greater than that of unchallenged controls or of lambs exposed only to P. haemolytica. However, this finding was complicated by the response to P13 virus. Lymphocytes from lung washings of all lambs failed to respond in a lymphocyte stimulation test to phytohaemagglutinin while blood lymphocytes did respond. There was little specific response to P. haemolytica antigen in the test.

Patient comfort and plasma lignocaine concentrations during fibreoptic bronchoscopy

In a preliminary prospective study, eleven outpatients undergoing fibreoptic bronchoscopy using a titrated dose of topical lignocaine anaesthesia were studied. Patient comfort, lignocaine dosage and resultant plasma concentrations were measured at four stages during the procedure. Large total doses, mean 512 (SD 55) mg lignocaine, were frequent and systemic absorption was unpredictable with two patients having plasma concentrations in the toxic range (greater than 5 micrograms/ml). Peak plasma concentrations, mean 2.3 (SD 1.4) micrograms/ml, occurred 30 to 40 minutes after commencement of topical application and coincided with completion of the procedure. No correlation was found between the individual dose of lignocaine administered and either the resultant plasma concentration or patient comfort scores. In an effort to minimise potential lignocaine toxicity, a fixed total dose technique (lignocaine 370 mg) was studied in a further twenty-one patients. No change in patient comfort scores and no toxic plasma concentrations were observed. Mean completion plasma concentration was 2.0 (SD 1.0) micrograms/ml. No clinical toxicity was observed in either group. Fibreoptic bronchoscopy in both groups using topical lignocaine anaesthesia without premedication or intravenous supplementation was well tolerated.

The role of H2 receptor antagonist premedication in pregnant day care patients

In a randomised study of 132 pregnant outpatients, the effect on gastric volume and pH of oral premedication with a single dose of an H2 antagonist was investigated. Either cimetidine 400 mg (n = 33), or ranitidine 150 mg (n = 33), were given 90 to 120 minutes before scheduled surgery. Mean pH was significantly higher in cimetidine (5.0) and ranitidine (5.2) groups, and mean volume was significantly lower in cimetidine (13.2 ml) and ranitidine (11.1 ml) groups compared with 66 untreated patients (pH 1.6, volume 22.1 ml). A gastric pH less than or equal to 2.5 was found in 97 per cent of unpremedicated patients and 35 per cent of these patients also had a gastric volume greater than or equal to 25 ml. Eighty-three per cent of patients received their premedication within 75-200 minutes of surgery. Patients premedicated within that range had a significantly lower incidence of either a gastric pH less than or equal to 2.5 or a volume greater than or equal to 25 ml (p less than 0.01). Both cimetidine and ranitidine significantly reduced the number of patients with these risk factors. Four patients, however, in the cimetidine group had both a pH less than or equal to 2.5 and a volume greater than or equal to 25 ml. Pharmacological manipulation of the gastric environment does not prevent aspiration and clearly cannot be substituted for careful airway management and vigilance on the part of the anaesthetist. However, premedication of pregnant outpatients with a single, oral dose of an H2 antagonist is a simple, inexpensive, safe and effective way of reducing the risk of a severe aspiration pneumonitis.

Effects of Pasteurella haemolytica cytotoxin on ovine peripheral blood leucocytes and lymphocytes obtained from gastric lymph

Ovine peripheral blood leucocytes were separated on discontinuous Percoll density gradients into fractions rich in lymphocytes (PBLy) and polymorphonuclear leucocytes. Supernatant fluid from a dialysis sac culture of Pasteurella haemolytica biotype A serotype 1 (A1) was cytotoxic to these leucocytes in vitro. PBLy retained viability after storage in liquid nitrogen and could be employed in cytotoxicity assays. However, sheep cannulated via the common gastric lymph duct were an excellent source of large numbers of homogeneous lymphoid cells (GLy) which also stored well in liquid nitrogen. As both freshly collected and stored GLy were killed by culture supernatant fluid GLy offer advantages as target cells for further characterisation of the extracellular cytotoxin produced by P. haemolytica. From the results obtained, it is considered that all ovine leucocytes are susceptible to P. haemolytica cytotoxin.

Lumbar extension in Duchenne muscular dystrophy: effect on lateral curvature

The purpose of this study was to investigate the hypothesis that a lumbar pad producing extension of the lumbar spine is of value in posture support seats for children with Duchenne muscular dystrophy. Our method was to establish whether or not an increase in lumbar lordosis produced any increase in resistance to static lateral curvature of the supine lumbar spine. Nine boys with Duchenne muscular dystrophy were studied at an age when they were about to go into a wheelchair or had recently become wheelchair mobile. In each case the child lay supine on low-friction material on an x-ray table while the spine was flexed first to the right and then to the left, with and without a lumbar pad, by a predetermined force. The degree of lateral curvature was measured from anteroposterior radiographs. While lateral forces were applied when the boys were supine rather than seated, the results failed to show a difference in curvature with or without the lumbar pad.

Orthotic management of scoliosis in Duchenne muscular dystrophy

This study investigates the effectiveness of spinal supports and seating systems in retarding the progress of spinal curvature in Duchenne muscular dystrophy. The approach was to take six monthly radiographs of children with this disease attending the Regency Park Centre sitting in their wheelchairs with their usual spinal supports. Scoliosis progressed from a mean value of approximately 10 degrees for children under 12 years to a value of the order of 75 degrees by the age of 16 to 18 years. The rate of progression peaked at an average of more than 1 degree per month between 14 and 18 years. The curvatures observed using modular seats, spinal jackets and custom-molded seats were not significantly different from those observed using unmodified wheelchair seats.

Cytotoxic effect of Pasteurella haemolytica on ovine bronchoalveolar macrophages in vitro

Live Pasteurella haemolytica A1 was shown to have a cytotoxic effect on suspensions of sheep bronchoalveolar macrophages. Cytotoxic activity was also demonstrable in bacteria-free supernatants from suspensions containing P. haemolytica. Heat-killed and ultra-violet killed organisms of P. haemolytica and live Staphylococcus aureus were not toxic to sheep BAM. These results suggest that a bacterial cell-free cytotoxin is produced by metabolically active P. haemolytica. Guinea-pig peritoneal macrophages, McCoy and pig kidney epithelial cell suspensions were unaffected by live P. haemolytica and supernatant from P. haemolytica cultures, indicating that the cytotoxin may only affect phagocytic cells of ovine or bovine origin.

A comparison between innominate osteotomy and hip spica in the treatment of Legg-Perthes' disease

Thirty-eight cases of Legg-Perthes' disease treated by innominate osteotomy have been reviewed and compared with 33 cases, matched for age and severity, treated in recumbency in plaster hip spicas. The results were similar in the two groups, the radiologic results in the innominate osteotomy group being marginally worse. There was a high incidence of poor results in both groups in those over the age of eight years at the onset of symptoms, especially if femoral "head at risk" signs were present. Other methods of treatment need to be provided for these older children.

Modular seating for paralytic scoliosis: design and initial experience

The conventional wheelchair sling seat provides little or no support to the spine of a child with myopathy or neurogenic muscular weakness. As the spinal muscles become weaker scoliosis may develop with associated deformity, pain and restriction of cardio-respiratory function. If muscle weakness is severe, the resultant fully developed deformity is virtually impossible to treat. Slowing the rate of increase of the deformity is, therefore, the most hopeful avenue of attack. This work addresses the hypothesis that custom moulded seating can increase sitting comfort and slow the rate of progression of spinal curvature in children with paralytic scoliosis, and further, that a range of standard or modular seats can achieve these goals at less cost. Previous work on this problem has ranged from simply padding the armrest, in order to distribute force over the rib cage, through to custom moulded seating. Our initial experience with custom moulding, using the bean bag evacuation and consolidation technique, produced several comfortable seats although the technique was labour intensive and therefore costly. This led us to attempt to develop a method of providing comfortable seating that would help control spinal deformity at reasonable cost. This paper describes the design of a standardized seating system for school age children with myopathy or neurogenic muscular weakness. Preliminary results indicate that this technique may have advantages over alternative methods of treatment. The radiological study is continuing.

The nuclide bone-scan in the diagnosis and management of Perthes' disease

The nuclide bone-scan will reliably diagnose Perthes' disease with a sensitivity of 0.98 and a specificity of 0.95. The comparable figures for radiographic sensitivity and specificity are respectively 0.92 and 0.78. In addition, it is possible on the scan to recognise the onset of revascularisation of the femoral capital epiphysis some months before there are radiographic signs of new bone formation. Scintigraphy also suggests that in some cases of transient synovitis there may bae a period of reversible ischaemia of the capital epiphysis, which may have relevance to the pathogenesis of Perthes' disease.