Recommendations for rescue of a submerged unresponsive compressed-gas diver.

The Diving Committee of the Undersea and Hyperbaric Medical Society has reviewed available evidence in relation to the medical aspects of rescuing a submerged unresponsive compressed-gas diver. The rescue process has been subdivided into three phases, and relevant questions have been addressed as follows. Phase 1, preparation for ascent: If the regulator is out of the mouth, should it be replaced? If the diver is in the tonic or clonic phase of a seizure, should the ascent be delayed until the clonic phase has subsided? Are there any special considerations for rescuing rebreather divers? Phase 2, retrieval to the surface: What is a "safe" ascent rate? If the rescuer has a decompression obligation, should they take the victim to the surface? If the regulator is in the mouth and the victim is breathing, does this change the ascent procedures? If the regulator is in the mouth, the victim is breathing, and the victim has a decompression obligation, does this change the ascent procedures? Is it necessary to hold the victim's head in a particular position? Is it necessary to press on the victim's chest to ensure exhalation? Are there any special considerations for rescuing rebreather divers? Phase 3, procedure at the surface: Is it possible to make an assessment of breathing in the water? Can effective rescue breaths be delivered in the water? What is the likelihood of persistent circulation after respiratory arrest? Does the recent advocacy for "compression-only resuscitation" suggest that rescue breaths should not be administered to a non-breathing diver? What rules should guide the relative priority of in-water rescue breaths over accessing surface support where definitive CPR can be started? A "best practice" decision tree for submerged diver rescue has been proposed.

A retrospective audit of three different regional anaesthetic techniques for circumcision in children.

Postoperative analgesia for male circumcision surgery has been traditionally provided by a landmark-based dorsal penile nerve block (DPNB-LM) or by caudal epidural analgesia (CEA). In this study we report on a retrospective analysis of the effectiveness and safety of CEA, DPNB-LM and ultrasound-guided dorsal penile nerve block (DPNB-US) in our institution over a six-year period. Information was gathered from each patient's medical record. A total of 216 circumcisions were performed on patients aged from five months to 15 years. One hundred and fifteen patients received CEA, 46 DPNB-LM and 55 DPNB-US. Patients in the DPNB-LM group required rescue morphine administration in the recovery unit more frequently (30.4%) than either the DPNB-US (3.5%) or CEA groups (3.6%). Similarly, the DPNB-LM group required a larger total dose of morphine, and had longer recovery ward stays than CEA or DPNB-US groups. Time to first analgesia was greatest for the CEA group while there was no significant difference between time to first analgesia for DPNB-LM and DPNB-US. Sixty-three percent of patients in the DPNB-LM group, 1.7% of CEA and 5.5% of the DPNB-US required intraoperative opiates (P < 0.0001). There was no difference in time to hospital discharge.

Arterial gas embolism: a review of cases at Prince of Wales Hospital, Sydney, 1996 to 2006.

Arterial gas embolism may occur as a complication of diving or certain medical procedures. Although relatively rare, the consequences may be disastrous. Recent articles in the critical care literature suggest the non-hyperbaric medical community may not be aware of the role for hyperbaric oxygen therapy in non-diving related gas embolism. This review is part of an Australian appraisal of experience in the management of arterial gas embolism over the last 10 years. We identified all patients referred to Prince of Wales Hospital Department of Diving and Hyperbaric Medicine with a diagnosis of arterial gas embolism from 1996 to 2006. Twenty-six patient records met our selection criteria, eight iatrogenic and 18 diving related. All patients were treated initially with a 280 kPa compression schedule. At discharge six patients were left with residual symptoms. Four were left with minor symptoms that did not significantly impact quality of life. Two remained severely affected with major neurological injury. Both had non-diving-related arterial gas embolism. There was a good outcome in the majority of patients who presented with arterial gas embolism and were treated with compression.

The synthesis and enzymic hydrolysis of (E)-2-[2,3-2H2]propenyl glucosinolate: confirmation of the rearrangement of the thiohydroximate moiety.

(E)-2-[2,3-2H2]propenyl glucosinolate was synthesised starting from (E)-[3,4-2H2]but-3-en-1-ol, which was produced by reduction of but-3-yn-1-ol with deuterium gas in the presence of Lindlar's catalyst. The synthesis of (E)-2-[2,3-2H2]propenyl glucosinolate was completed via the nitro intermediate to form the basic desulphoglucosinolate skeleton. The (E)-2-[2,3-2H2]propenyl glucosinolate was fully characterised and deuterium NMR spectroscopy used to examine the rearrangement of the thiohydroximate to the isothiocyanate and thiocyanate.

Recompression and adjunctive therapy for decompression illness.

BACKGROUND: Decompression illness (DCI) is due to bubble formation in the blood or tissues following the breathing of compressed gas. Clinically, DCI may range from a trivial illness to loss of consciousness, death or paralysis. Recompression is the universally accepted standard for the treatment of DCI. When recompression is delayed, a number of strategies have been suggested in order to improve the outcome. OBJECTIVES: To examine the effectiveness and safety of both recompression and adjunctive therapies in the treatment of DCI. SEARCH STRATEGY: We searched CENTRAL (The Cochrane Library 2005, Issue 2); MEDLINE (1966 to August 2005); CINAHL (1982 to August 2005); EMBASE (1980 to August 2005); the Database of Randomised Controlled Trials in Hyperbaric Medicine (August 2005), and hand-searched journals and texts. SELECTION CRITERIA: We included randomized controlled trials that compared the effect of any recompression schedule or adjunctive therapy with a standard recompression schedule. We applied no language restrictions. DATA COLLECTION AND ANALYSIS: Three authors extracted the data independently. We assessed each trial for internal validity and resolved differences by discussion. Data was entered into RevMan 4.2. MAIN RESULTS: Two randomized controlled trials satisfied the inclusion criteria. Pooling of data was not possible. In one study there was no evidence of improved effectiveness with the addition of a non-steroidal anti-inflammatory drug (tenoxicam) to routine recompression therapy (at six weeks: relative risk (RR) 1.04, 95% confidence interval (CI) 0.90 to 1.20, P = 0.58) but there was a reduction in the number of compressions required when tenoxicam was added (P = 0.01, 95% CI 0 to 1). In the other study, the odds of multiple recompressions was lower with a helium and oxygen (heliox) table compared to an oxygen treatment table (RR 0.56, 95% CI 0.31 to 1.00, P = 0.05). AUTHORS' CONCLUSIONS: Recompression therapy is standard for the treatment of DCI, but there is no randomized controlled trial evidence. Both the addition of an NSAID or the use of heliox may reduce the number of recompressions required, but neither improves the odds of recovery. The application of either of these strategies may be justified. The modest number of patients studied demands a cautious interpretation. Benefits may be largely economic and an economic analysis should be undertaken. There is a case for large randomized trials of high methodological rigour in order to define any benefit from the use of different breathing gases and pressure profiles during recompression therapy.

Hyperbaric oxygen for idiopathic sudden sensorineural hearing loss and tinnitus.

BACKGROUND: Idiopathic sudden sensorineural hearing loss (ISSHL) with or without tinnitus is common and presents a health problem with significant effect on quality of life. Hyperbaric oxygen therapy (HBOT) may improve oxygen supply to the inner ear and, it is postulated, may result in an improvement in hearing and/or a reduction in the intensity of tinnitus. OBJECTIVES: To assess the benefits and harms of HBOT for treating ISSHL and/or tinnitus. SEARCH STRATEGY: We initially searched in June 2004 and repeated the search in June 2006. Our search included the Cochrane Ear, Nose and Throat Disorders Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 2 2006), MEDLINE (1951 to 2006), EMBASE (1974 to 2006), CINAHL, Database of Randomised Trials in Hyperbaric Medicine (DORCTHIM), AMED, LILACS, KOREAMED, INDMED, National Research Register (NRR), CSA, ISI PROCEEDINGS and ZETOC. SELECTION CRITERIA: Randomised studies comparing the effect on ISSHL and/or tinnitus of therapeutic regimens which include HBOT with those that exclude HBOT. DATA COLLECTION AND ANALYSIS: Three authors independently evaluated the quality of the relevant trials using the validated Oxford-Scale (Jadad 1996) and extracted the data from the included trials. MAIN RESULTS: Six trials contributed to this review (308 subjects). Pooled data from two trials involving 114 patients did not show any significant improvement in the chance of a 50% increase in hearing threshold on Pure Tone Average (PTA) when HBOT was used (relative risk [RR] with HBOT 1.53, 95% CI 0.85 to 2.78, P = 0.16), but did show a significantly increased chance of a 25% increase in PTA (RR 1.39, 95% CI 1.05 to 1.84, P = 0.02). There was a 22% greater chance of improvement with HBOT, and the number needed to treat (NNT) to achieve one extra good outcome was five (95% CI 3 to 20). A single trial involving 50 subjects also suggested significantly more improvement in the mean PTA threshold with HBOT, expressed as a percentage of baseline (WMD 37%, 95% CI 22% to 53%, P < 0.001). The significance of any improvement following HBOT in a subjective rating of tinnitus could not be assessed due to poor reporting. There were no significant improvements in hearing or tinnitus reported in the single study to examine chronic presentation (six months) of ISSHL and/or tinnitus. AUTHORS' CONCLUSIONS: For people with early presentation of ISSHL, the application of HBOT significantly improved hearing loss, but the clinical significance of the level of improvement is not clear. We could not assess the effect of HBOT on tinnitus by pooled data analysis. The routine application of HBOT to these patients cannot be justified from this review. In view of the modest number of patients, methodological shortcomings and poor reporting, this result should be interpreted cautiously, and an appropriately powered trial of high methodological rigour is justified to define those patients (if any) who can be expected to derive most benefit from HBOT. There is no evidence of a beneficial effect of HBOT on chronic presentation of ISSHL and/or tinnitus and we do not recommend use of HBOT for this purpose based on the single study available.

Hyperbaric oxygen therapy for acute ischaemic stroke.

BACKGROUND: Most cases of stroke are caused by impairment of blood flow to the brain (ischaemia) which results in a reduction in oxygen available and subsequent cell death. It has been postulated that hyperbaric oxygen therapy (HBOT) may reduce the volume of brain that will die by greatly increasing the oxygen available, and it may further improve outcome by reducing brain swelling. Some centres are using HBOT routinely to treat stroke. OBJECTIVES: To assess the effectiveness and safety of adjunctive HBOT in the treatment of acute ischaemic stroke. SEARCH STRATEGY: We searched the Cochrane Stroke Group Trials Register (last searched 9 January 2004), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 3, 2004), MEDLINE (1966 to July 2004), EMBASE (1980 to July 2004), CINAHL (1982 to July 2004), and DORCTHIM (Database of Randomised Controlled Trials in Hyperbaric Medicine) (from inception to 2004). We handsearched journals and conference proceedings, searched reference lists of articles, and contacted researchers in an effort to identify additional published and unpublished studies. SELECTION CRITERIA: We included all randomised controlled trials that compared the effect of adjunctive HBOT with no HBOT (no treatment or sham). DATA COLLECTION AND ANALYSIS: Two authors used standardised forms to extract the data independently. Each trial was assessed for internal validity with differences resolved by discussion. Data were extracted and entered into RevMan 4.2. MAIN RESULTS: Three randomised controlled trials (106 participants) satisfied the inclusion criteria. The methodological quality of the trials varied but was generally high. Data could be pooled for a limited number of clinically important outcomes. There were no significant differences in mortality rate at six months in those receiving HBOT compared to the control group (relative risk 0.61, 95% confidence interval (CI) 0.17 to 2.2, P value 0.45). Two of 15 scale measures of disability and functional indicated an improvement following HBOT, both at one year follow up: the mean Trouillas Disability Scale was lower with HBOT (mean difference (MD) 2.2 points reduction with HBOT, 95% CI 0.15 to 4.3, P value 0.04) and the mean Orgogozo Scale was higher (MD 27.9 points, 95% CI 4.0 to 51.8, P value 0.02). These improvements were not reflected in other trials or functional scales. AUTHORS' CONCLUSIONS: This systematic review has not found evidence to show that HBOT improves clinical outcomes when applied during the acute presentation of ischaemic stroke. While evidence from the three randomised controlled trials is insufficient to provide clear guidelines for practice, clinical benefit does not seem likely. Further research is required to better define the role of HBOT in this condition.

Hyperbaric oxygen therapy for late radiation tissue injury.

BACKGROUND: Cancer is a significant global health problem. Radiotherapy is a treatment for many cancers and about 50% of patients having radiotherapy with be long-term survivors. Some will experience LRTI developing months or years later. HBOT has been suggested for LRTI based upon the ability to improve the blood supply to these tissues. It is postulated that HBOT may result in both healing of tissues and the prevention of problems following surgery. OBJECTIVES: To assess the benefits and harms of HBOT for treating or preventing LRTI. SEARCH STRATEGY: We searched The Cochrane Central Register of Controlled Trials (CENTRAL) Issue 3, 2004, MEDLINE, EMBASE, CINAHL and DORCTHIM (hyperbaric RCT register) in September 2004. SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing the effect of HBOT versus no HBOT on LRTI prevention or healing. DATA COLLECTION AND ANALYSIS: Three reviewers independently evaluated the quality of the relevant trials using the guidelines of the Cochrane Handbook Clarke 2003) and extracted the data from the included trials. MAIN RESULTS: Six trials contributed to this review (447 participants). For pooled analyses, investigation of heterogeneity suggested important variability between trials. From single studies there was a significantly improved chance of healing following HBOT for radiation proctitis (relative risk (RR) 2.7, 95% confidence Interval (CI) 1.2 to 6.0, P = 0.02, numbers needed to treat (NNT) = 3), and following both surgical flaps (RR 8.7, 95% CI 2.7 to 27.5, P = 0.0002, NNT = 4) and hemimandibulectomy (RR 1.4, 95% CI 1.1 to 1.8, P = 0.001, NNT = 5). There was also a significantly improved probability of healing irradiated tooth sockets following dental extraction (RR 1.4, 95% CI 1.1 to 1.7, P = 0.009, NNT = 4). There was no evidence of benefit in clinical outcomes with established radiation injury to neural tissue, and no data reported on the use of HBOT to treat other manifestations of LRTI. These trials did not report adverse effects. AUTHORS' CONCLUSIONS: These small trials suggest that for people with LRTI affecting tissues of the head, neck, anus and rectum, HBOT is associated with improved outcome. HBOT also appears to reduce the chance of osteoradionecrosis following tooth extraction in an irradiated field. There was no such evidence of any important clinical effect on neurological tissues. The application of HBOT to selected patients and tissues may be justified. Further research is required to establish the optimum patient selection and timing of any therapy. An economic evaluation should be also be undertaken. There is no useful information from this review regarding the efficacy or effectiveness of HBOT for other tissues.

Hyperbaric oxygen therapy for promoting fracture healing and treating fracture non-union.

BACKGROUND: Hyperbaric oxygen therapy (HBOT) consists of intermittently administering 100% oxygen at pressures greater than one atmosphere absolute (ATA) in a pressure vessel. This technology has been used to treat a variety of diseases and has been described as helping patients who have delayed healing or established non-union of bony fractures. OBJECTIVES: The aim of this review was to assess the evidence for the benefit of hyperbaric oxygen treatment (HBOT) for the treatment of delayed bony healing and established non-union of bony fractures. SEARCH STRATEGY: We searched the Cochrane Musculoskeletal Injuries Group trials register (to January week 3, 2004), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 4, 2003), MEDLINE (OVID 1966 to January week 3, 2004), CINAHL (OVID 1982 to January week 3, 2004), EMBASE (OVID 1980 to February 2004), the locally developed Database of Randomised Controlled Trials in Hyperbaric Medicine (available at www.hboevidence.com) from inception to March 2004, and reference lists of articles. SELECTION CRITERIA: We aimed to include all randomised controlled trials that compared the effect of HBOT with no HBOT (no treatment or sham). DATA COLLECTION AND ANALYSIS: Two authors using standardised forms attempted to extract data independently. MAIN RESULTS: No trials met the inclusion criteria. We excluded one trial that compared HBOT with no treatment because no clinical outcomes were reported. AUTHORS' CONCLUSIONS: This systematic review failed to locate any relevant clinical evidence to support or refute the effectiveness of HBOT for the management of delayed union or established non-union of bony fractures. Good quality clinical trials are needed to define the role, if any, of HBOT in the treatment of these injuries.

Hyperbaric oxygen for idiopathic sudden sensorineural hearing loss and tinnitus.

BACKGROUND: Idiopathic sudden sensorineural hearing loss (ISSHL) with or without tinnitus is common and presents a health problem with significant effect on quality of life. Hyperbaric oxygen therapy (HBOT) may improve oxygen supply to the inner ear and thereby result in an improvement in hearing and/or a reduction in the intensity of tinnitus. OBJECTIVES: To assess the benefits and harms of HBOT for treating ISSHL and tinnitus. SEARCH STRATEGY: We searched the Cochrane ENT Specialist Register (June 2004), CENTRAL (The Cochrane Library Issue 3, 2004), MEDLINE (1966 to 2004), EMBASE (1974 to 2004), CINAHL (1982 to 2004), DORCTHIM (1996 to 2004), and reference lists of articles. Researchers in the field were contacted. SELECTION CRITERIA: Randomised studies comparing the effect on ISSHL and/or tinnitus of therapeutic regimens which include HBOT with those that exclude HBOT. DATA COLLECTION AND ANALYSIS: Three reviewers independently evaluated the quality of the relevant trials using the validated Jadad 1996 Oxford-Scale and extracted the data from the included trials. MAIN RESULTS: Five trials contributed to this review (254 subjects, 133 receiving HBOT and 120 control). Pooled data from two trials involving 114 patients (45% of the total) suggested there was a trend towards, but no significant increase in, the chance of a 50% increase in hearing threshold on Pure Tone Average (PTA) over four frequencies when HBOT was used (relative risk (RR) for good outcome with HBOT 1.53, 95% confidence interval (CI) 0.85 to 2.78, P = 0.16). The chance of achieving a 25% increase with HBOT was, however, statistically significant (RR 1.39, 95% CI 1.05 to 1.84, P = 0.02). Fifty-six per cent of the control subjects achieved this outcome versus 78% of the HBOT subjects, with the number-needed-to-treat (NNT) to achieve one extra good outcome being 5 (95% CI 3 to 20). A single trial involving 50 subjects (20% of the total) also suggested a significant improvement in the mean PTA threshold expressed as a percentage of baseline (61% improvement with HBOT, 24% with control, WMD 37%, 95% CI 22% to 53%). The effect of HBOT in tinnitus could not be assessed due to poor reporting. There were no significant improvements in hearing or tinnitus reported in the single study to examine the effect of HBOT on a chronic presentation (six months) of ISSHL and/or tinnitus. AUTHORS' CONCLUSIONS: For people with early presentation of ISSHL, the application of HBOT significantly improved hearing loss, but the clinical significance of the level of improvement is not clear. We could not assess the effect of HBOT on tinnitus by pooled analysis. The routine application of HBOT to these patients cannot be justified from this review. In view of the modest number of patients, methodological shortcomings and poor reporting, this result should be interpreted cautiously, and an appropriately powered trial of high methodological rigour is justified to define those patients (if any) who can be expected to derive most benefit from HBOT. There is no evidence of a beneficial effect of HBOT on chronic presentation of ISSHL and/or tinnitus.

Hyperbaric oxygen therapy for the adjunctive treatment of traumatic brain injury.

BACKGROUND: Traumatic brain injury is common and presents a health problem with significant effect on quality of life. Hyperbaric oxygen therapy (HBOT) has been suggested to improve oxygen supply to the injured brain and, therefore, to reduce the volume of brain that will ultimately perish. It is postulated that the addition of HBOT to the standard intensive care regimen may result in a reduction in patient death and disability as a result of these additional brain-preserving effects. OBJECTIVES: To assess the benefits and harms of adjunctive HBOT for treating traumatic brain injury. SEARCH STRATEGY: We searched CENTRAL (The Cochrane Library Issue 4, 2003), MEDLINE (1966 - 2003), EMBASE (1974 - 2003), CINAHL (1982 - 2003), DORCTHIM (1996 - 2003), and reference lists of articles. Relevant journals were handsearched and researchers in the field were contacted. SELECTION CRITERIA: Randomised studies comparing the effect on traumatic brain injury of therapeutic regimens which include HBOT with those that exclude HBOT (with or without sham therapy). DATA COLLECTION AND ANALYSIS: Three reviewers independently evaluated the quality of the relevant trials using the validated Oxford-Scale (Jadad 1996) and extracted the data from the included trials. MAIN RESULTS: Four trials contributed to this review (382 patients, 199 receiving HBOT and 183 control). There was a trend towards, but no significant increase in, the chance of a favourable outcome when defined as full recovery, Glasgow outcome score 1 or 2, or return to normal activities of daily living (relative risk [RR] for good outcome with HBOT 1.94, 95% confidence interval [CI] 0.92 to 4.08, P=0.08). Pooled data from the three trials with 327 patients that reported mortality, showed a significant reduction in the risk of dying when HBOT was added to the treatment regimen (RR 0.69, 95% CI 0.54 to 0.88, P=0.003). Heterogeneity between studies was low (I(2) =0%), and sensitivity analysis for the allocation of dropouts did not affect that result. This analysis suggests we would have to treat seven patients to avoid one extra death (number needed to treat [NNT] 7, 95% CI 4 to 22). One trial suggested intracranial pressure was favourably lower in those patients receiving HBOT in whom myringotomies had been performed (WMD with myringotomy -8.2 mmHg, 95% CI -14.7 mmHg to -1.7 mmHg, P=0.01), while in two trials there was a reported incidence of 13% for significant pulmonary impairment in the group receiving HBOT versus 0% in the non-HBOT group (P=0.007). REVIEWERS' CONCLUSIONS: In people with traumatic brain injury, the addition of HBOT significantly reduced the risk of death but not of favourable clinical outcome. The routine application of HBOT to these patients cannot be justified from this review. In view of the modest number of patients, methodological shortcomings and poor reporting, this result should be interpreted cautiously, and an appropriately powered trial of high methodological rigour is justified to define those patients (if any) who can be expected to derive most benefit from HBOT.

Hyperbaric oxygen therapy for thermal burns.

BACKGROUND: Hyperbaric oxygen therapy (HBOT) consists of intermittently administering 100% oxygen at pressures greater than 1 atmosphere in a pressure vessel. This technology has been used to treat a variety of disease states and has been described as helping patients who have sustained burns. OBJECTIVES: The aim of this review was to assess the evidence for the benefit of hyperbaric oxygen treatment (HBOT) for the treatment of thermal burns. SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register (The Cochrane Library, Issue 3, 2002), MEDLINE (Ovid 1966 to November Week 2, 2003), CINAHL (Ovid 1982 to December Week 2 2003), EMBASE (Ovid 1980 to September 2003), DORCTHIM (Database of Randomised Controlled Trials in Hyperbaric Medicine) from inception to 2003, and reference lists of articles. SELECTION CRITERIA: We included all randomised controlled trials that compared the effect of HBOT with no HBOT (no treatment or sham). DATA COLLECTION AND ANALYSIS: Two authors using standardised forms extracted the data independently. Each trial was assessed for internal validity with differences resolved by discussion. Data was extracted and entered into RevMan 4.2.3. MAIN RESULTS: Four randomised controlled trials were identified, of which two satisfied the inclusion criteria. The trials were of poor methodological quality. As a result, it was difficult to have confidence in the individual results and it would not have been appropriate to attempt to pool the data. One trial reported no difference in length of stay, mortality, or number of surgeries between the control and HBO-treated groups once these variables were adjusted for the patient's condition. The second trial reported mean healing times that were shorter in patients exposed to HBOT (mean: 19.7 days versus 43.8 days). REVIEWERS' CONCLUSIONS: This systematic review has not found sufficient evidence to support or refute the effectiveness of HBOT for the management of thermal burns. Evidence from the two randomised controlled trials is insufficient to provide clear guidelines for practice. Further research is needed to better define the role of HBOT in the treatment of thermal burns.

Ocular tear film bubble counts after recreational compressed air diving.

Other authors have demonstrated an increase in tear film bubble counts following dry, compressed air dives. We examined the lower tear film meniscus for the presence of bubbles in 42 divers after compressed air dives on a single day and in 11 divers undergoing repetitive, multi-day diving exposures over 5 days. After diving, bubble counts increased significantly (P < 0.01) from predive values. From a predive median (inter-quartile range) of 0 (0-0.33) bubbles/eye, single-day divers reached a maximum bubble count at 48 h after diving of 1 (0-2.25) bubbles/eye. Similarly, from a predive count of 0.33 (0-1) bubbles/eye, multi-day divers had increased bubble counts from 24 h following their first dive until 24 h following their final dive when counts were 1.67 (0.92-3.08) bubbles/eye. Bubble counts were not significantly correlated with inert gas load, body mass index, age, or diving experience. We confirm that tear film bubble counts are raised after wet compressed air diving as previously described following dry diving.

Postoperative sore throat and hoarseness following tracheal intubation using air or saline to inflate the cuff--a randomized controlled trial.

Sore throat and hoarseness following tracheal intubation is common. The aetiology may include high tracheal cuff pressures. We performed a double-blind, randomized controlled trial in 126 intubated patients to compare the incidence and severity of sore throat and hoarseness following inflation of the cuff using air or saline. Intra-cuff pressures were compared to assess any change due to inward diffusion of nitrous oxide. The incidence of significant sore throat and/or hoarseness overall was 15.0%. There was no statistically significant difference between the groups (air 15.9%, saline 14.5%). In the air group mean intra-cuff pressure increased significantly (start 14.0 mmHg, end 40.9 mmHg), while in the saline group there was no significant increase (start 12.7 mmHg, end 14.6 mmHg). The substitution of saline reliably results in sustained low intra-cuff pressures but high tracheal cuff pressure is not an important factor in the development of sore throat or hoarseness postoperatively within the pressure range and duration of operation studied.

Metabolite profiling of sesquiterpene lactones from Lactuca species. Major latex components are novel oxalate and sulfate conjugates of lactucin and its derivatives.

Wounding leaves or stems of Lactuca species releases a milky latex onto the plant surface. We have examined the constituents of latex from Lactuca sativa (lettuce) cv. Diana. The major components were shown to be novel 15-oxalyl and 8-sulfate conjugates of the guaianolide sesquiterpene lactones, lactucin, deoxylactucin, and lactucopicrin. The oxalates were unstable, reverting to the parent sesquiterpene lactone on hydrolysis. Oxalyl derivatives have been reported rarely from natural sources. The sulfates were stable and are the first reported sesquiterpene sulfates from plants. Unusual tannins based on 4-hydroxyphenylacetyl conjugates of glucose were also identified. Significant qualitative and quantitative variation was found in sesquiterpene lactone profiles in different lettuce varieties and in other Lactuca spp. The proportions of each conjugate in latex also changed depending on the stage of plant development. A similar profile was found in chicory, in which oxalyl conjugates were identified, but the 8-sulfate conjugates were notably absent. The presence of the constitutive sesquiterpene lactones was not correlated with resistance to pathogens but may have a significant bearing on the molecular basis of the bitter taste of lettuce and related species. The induced sesquiterpene lactone phytoalexin, lettucenin A, was found in the Lactuca spp. but not in chicory.

Localization of hydrogen peroxide accumulation during the hypersensitive reaction of lettuce cells to Pseudomonas syringae pv phaseolicola.

The active oxygen species hydrogen peroxide (H2O2) was detected cytochemically by its reaction with cerium chloride to produce electron-dense deposits of cerium perhydroxides. In uninoculated lettuce leaves, H2O2 was typically present within the secondary thickened walls of xylem vessels. Inoculation with wild-type cells of Pseudomonas syringae pv phaseolicola caused a rapid hypersensitive reaction (HR) during which highly localized accumulation of H2O2 was found in plant cell walls adjacent to attached bacteria. Quantitative analysis indicated a prolonged burst of H2O2 occurring between 5 to 8 hr after inoculation in cells undergoing the HR during this example of non-host resistance. Cell wall alterations and papilla deposition, which occurred in response to both the wild-type strain and a nonpathogenic hrpD mutant, were not associated with intense staining for H2O2, unless the responding cell was undergoing the HR. Catalase treatment to decompose H2O2 almost entirely eliminated staining, but 3-amino-1,2,4-triazole (catalase inhibitor) did not affect the pattern of distribution of H2O2 detected. H2O2 production was reduced more by the inhibition of plant peroxidases (with potassium cyanide and sodium azide) than by inhibition of neutrophil-like NADPH oxidase (with diphenylene iodonium chloride). Results suggest that CeCl3 reacts with excess H2O2 that is not rapidly metabolized during cross-linking reactions occurring in cell walls; such an excess of H2O2 in the early stages of the plant-bacterium interaction was only produced during the HR. The highly localized accumulation of H2O2 is consistent with its direct role as an antimicrobial agent and as the cause of localized membrane damage at sites of bacterial attachment.

Hrp Mutant of Pseudomonas syringae pv phaseolicola Induces Cell Wall Alterations but Not Membrane Damage Leading to the Hypersensitive Reaction in Lettuce.

Both wild-type (S21-WT) and hrpD- (S21-533) strains of Pseudomonas syringae pv phaseolicola induced the formation of large paramural papillae in lettuce (Lactuca sativa) mesophyll cells adjacent to bacterial colonies. Localized alterations to the plant cell wall included deposition of hydroxyproline-rich glycoproteins, phe-nolics, and callose, and were associated with proliferation of the endoplasmic reticulum and multivesicular bodies. Tissue collapse during the hypersensitive reaction caused by S21-WT was associated with electrolyte leakage and rapid accumulation of the phy-toalexin lettucenin A, both of which followed membrane damage indicated by the failure of mesophyll cells to plasmolyze. A few cells lost the ability to plasmolyze after inoculation with S21-533, and low levels of lettucenin A were recorded, but neither leakage of electrolytes nor tissue collapse were detected. Dysfunction of the plasma membrane in cells adjacent to colonies of S21-WT led to extensive vacuolation of the cytoplasm, organelle disruption, and cytoplasmic collapse[mdash]changes unlike those occurring in cells undergoing apoptosis. Strain S21-533 remained viable within symptomless tissue, whereas cells of S21-WT were killed as a consequence of the hypersensitive reaction. Our observations emphasize the subtle coordination of the plant's response occurring at the subcellular level.

The significance of MALT histology in thyroid lymphoma: a review of patients from the BNLI and Royal Marsden Hospital.

Data from a series of 45 patients with Stage I and II non-Hodgkin's lymphoma (NHL) of the thyroid gland were analysed retrospectively to determine the incidence and prognostic significance of histopathological features of tumour origin from mucosa associated lymphoid tissue (MALT). The overall 5- and 10-year cause specific survival from NHL for the series was 79%. Evidence of tumour origin from MALT was the only significant prognostic factor for overall survival identified by multivariate analysis of the series (P < 0.01). A total of 31 (69%) tumours showed such evidence, the cause specific patient survival from NHL at 5 and 10 years being 90% compared with only 55% at 5 years for the 14 patients without such evidence. For patients given initial treatment with radiotherapy alone, those with evidence of tumour origin from MALT had a relatively low relapse rate and a relatively high success rate from salvage therapy, compared with a relatively high relapse rate and negligible success from salvage therapy in those without evidence of such tumour origin.

Non-Hodgkin's lymphoma of the testis.

Primary non-Hodgkin's lymphoma of the testis is rare. From 1976 to 1989 32 patients have been registered with the British National Lymphoma Investigation and two with the Institute of Urology. All 34 patients had disease of high grade histology (BNLI) although in four patients there were some areas with features similar to those described in lymphomas of Mucosal Associated Lymphoid Tissue (MALT). Twenty-three of 34 (67.5%) patients had early stage disease (I/II); 17/34 (50%) achieved complete remission from their initial treatment, and the relapse-free survival of these patients was 66% at 5 years. The disease-free survival for the 34 patients as a whole was 33% and their overall survival 39% at 5 years. The life expectancy for those presenting with advanced (stage III/IV) disease was very poor (median survival 9 months) with a low complete remission rate from chemotherapy. The salvage rate from recurrent disease (17%) was poor. Bilateral testicular involvement (18%) and a high rate of central nervous system disease (21%) occurred in the series, and two patients were HIV positive. Stage at presentation was the most important prognostic factor.