Perioperative Management and Outcomes in Patients With Autism Spectrum Disorder: A Retrospective Cohort Study

BACKGROUND

Autism spectrum disorder (ASD) is a neurocognitive disorder characterized by impairments in communication and socialization. There are little data comparing the differences in perioperative outcomes in children with and without ASD. We hypothesized that children with ASD would have higher postoperative pain scores than those without ASD.

METHODS

Pediatric patients undergoing ambulatory tonsillectomy/adenoidectomy, ophthalmological surgery, general surgery, and urologic procedures between 2016 and 2021 were included in this retrospective cohort study. ASD patients, defined by International Classification of Diseases-9/10 codes, were compared to controls utilizing inverse probability of treatment weighting based on surgical category/duration, age, sex, race and ethnicity, anesthetizing location, American Society of Anesthesiology physical status, intraoperative opioid dose, and intraoperative dexmedetomidine dose. The primary outcome was the maximum postanesthesia care unit (PACU) pain score, and secondary outcomes included premedication administration, behavior at induction, PACU opioid administration, postoperative vomiting, emergence delirium, and PACU length of stay.

RESULTS

Three hundred thirty-five children with ASD and 11,551 non-ASD controls were included. Maximum PACU pain scores in the ASD group were not significantly higher than controls (median, 5; interquartile range [IQR], 0-8; ASD versus median, 5; IQR, 0-8 controls; median difference [95% confidence interval {CI}] of 0 [-1.1 to 1.1]; P = .66). There was no significant difference in the use of premedication (96% ASD versus 95% controls; odds ratio [OR], 1.5; [95% CI, 0.9-2.7]; P = .12), but the ASD cohort had significantly higher odds of receiving an intranasal premedication (4.2% ASD versus 1.2% controls; OR, 3.5 [95% CI, 1.8-6.8]; P < .001) and received ketamine significantly more frequently (0.3% ASD versus <0.1% controls; P < .001). Children with ASD were more likely to have parental (4.9% ASD versus 1.0% controls; OR, 5 [95% CI, 2.1-12]; P < .001) and child life specialist (1.3% ASD versus 0.1% controls; OR, 9.9 [95% CI, 2.3-43]; P < .001) presence at induction, but were more likely to have a difficult induction (11% ASD versus 3.4% controls; OR, 3.42 [95% CI, 1.7-6.7]; P < .001). There were no significant differences in postoperative opioid administration, emergence delirium, vomiting, or PACU length of stay between cohorts.

CONCLUSIONS

We found no difference in maximum PACU pain scores in children with ASD compared to a similarly weighted cohort without ASD. Children with ASD had higher odds of a difficult induction despite similar rates of premedication administration, and significantly higher parental and child life specialist presence at induction. These findings highlight the need for future research to develop evidence-based interventions to optimize the perioperative care of this population.

Bovine TB surveillance in Great Britain in 2014

This report, provided by the APHA, summarises the key descriptive epidemiological parameters of bovine TB in cattle in Great Britain from January 1 to December 31, 2014. It summarises some of the temporal trends observed over a longer period and highlights some differences and similarities between Scotland, Wales and the three bovine TB risk areas of England. It updates the previous annual summaries for 2012 and 2013, also published inVeterinary Record(VR, June 14, 2014, vol 174, pp 600-604; March 28, 2015, vol 176, pp 326-330).

Consensus-based training and assessment model for general surgery

Background

Surgical education is becoming competency-based with the implementation of in-training milestones. Training guidelines should reflect these changes and determine the specific procedures for such milestone assessments. This study aimed to develop a consensus view regarding operative procedures and tasks considered appropriate for junior and senior trainees, and the procedures that can be used as technical milestone assessments for trainee progression in general surgery.

Methods

A Delphi process was followed where questionnaires were distributed to all 17 Canadian general surgery programme directors. Items were ranked on a 5-point Likert scale, with consensus defined as Cronbach's α of at least 0·70. Items rated 4 or above on the 5-point Likert scale by 80 per cent of the programme directors were included in the models.

Results

Two Delphi rounds were completed, with 14 programme directors taking part in round one and 11 in round two. The overall consensus was high (Cronbach's α = 0·98). The training model included 101 unique procedures and tasks, 24 specific to junior trainees, 68 specific to senior trainees, and nine appropriate to all. The assessment model included four procedures.

Conclusion

A system of operative procedures and tasks for junior- and senior-level trainees has been developed along with an assessment model for trainee progression. These can be used as milestones in competency-based assessments.

Service evaluation to establish the sensitivity, specificity and additional value of broad-range 16S rDNA PCR for the diagnosis of infective endocarditis from resected endocardial material in patients from eight UK and Ireland hospitals

Infective endocarditis (IE) can be diagnosed in the clinical microbiology laboratory by culturing explanted heart valve material. We present a service evaluation that examines the sensitivity and specificity of a broad-range 16S rDNA polymerase chain reaction (PCR) assay for the detection of the causative microbe in culture-proven and culture-negative cases of IE. A clinical case-note review was performed for 151 patients, from eight UK and Ireland hospitals, whose endocardial specimens were referred to the Microbiology Laboratory at Great Ormond Street Hospital (GOSH) for broad-range 16S rDNA PCR over a 12-year period. PCR detects the causative microbe in 35/47 cases of culture-proven IE and provides an aetiological agent in 43/69 cases of culture-negative IE. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the 16S rDNA PCR assay were calculated for this series of selected samples using the clinical diagnosis of IE as the reference standard. The values obtained are as follows: sensitivity = 67 %, specificity = 91 %, PPV = 96 % and NPV = 46 %. A wide range of organisms are detected by PCR, with Streptococcus spp. detected most frequently and a relatively large number of cases of Bartonella spp. and Tropheryma whipplei IE. PCR testing of explanted heart valves is recommended in addition to culture techniques to increase diagnostic yield. The data describing the aetiological agents in a large UK and Ireland series of culture-negative IE will allow future development of the diagnostic algorithm to include real-time PCR assays targeted at specific organisms.

Impact of Schmallenberg virus on British sheep farms during the 2011/2012 lambing season

British sheep farmers were invited to complete a questionnaire about the impact of Schmallenberg virus (SBV) on animal health, welfare and their own emotional wellbeing during the 2011–2012 lambing season, through Defra and Farming Industry websites, letters to farmers who had requested SBV laboratory tests and advertisement at Sheep 2012. The 494 responders included SBV confirmed (positive by RT-PCR) (n=76), SBV suspected by farmer (n=140) or SBV not suspected (n=278). Percentage of barren ewes was similar across SBV groups, however, lamb and ewe losses were higher on responder farms where SBV was confirmed or suspected. The median percentages of all lambs born (and lambs born deformed ) that died within one week of birth was 10.4 per cent (5.5 per cent), 7.0 per cent (2.9 per cent) and 5.3 per cent (0 per cent), respectively, on SBV confirmed, suspected and not suspected farms (P<0.001). Eight to 16 per cent of SBV confirmed or suspected farms reported lamb mortality of ≥40 per cent. Farmer perceived impact was greater where SBV was confirmed or suspected (P<0.001): 25 per cent reported a high impact on emotional wellbeing (4 per cent of SBV not suspected), 13 per cent reported a high impact on flock welfare and financial performance and 6 per cent were less likely to farm sheep next year because of SBV (<2 per cent in SBV not suspected). Overall, SBV impact has been large relative to reported sheep loss.

Sex-specific quantitative trait loci linked to autoresuscitation failure in SWR/J mice

Autoresuscitation (AR) is a highly conserved response among mammals, which allows survival from transient extreme hypoxia. During hypoxia, bradycardia, and hypoxic gasping develop after a brief period of hyperactivity. Normally, AR occurs if oxygen is restored during the gasping period where an initial heart rate increase is rapidly followed resumption or eupneic breathing. Humans and other mammals can survive multiple immediately repeated AR. A defective AR capacity has been implicated in Sudden Infant Death Syndrome. We had reported earlier that inbred strains of mice such as BALB/cJ could survive a characteristic number of immediately repeated AR trials, but that SWR/J mice failed to AR from a single hypoxic episode. We now report that strains closely related to SWR/J, FVB/N and SJL/J exhibit partial resuscitation defects relative to BALB/cJ or other mouse strains, establishing a genetic basis for variation in AR failure. The AR trial phenotype of BALB/cJ x SWR/J intercross F(1) and F(2) mice was consistent with BALB/cJ dominance and a discrete number of loci. Genome-wide mapping conducted with 60 intercross F(2) animals linked two loci to the number of AR trials survived, including one sex-specific locus with male expression, consistent with the observed 50% male bias for Sudden Infant Death Syndrome in humans. A locus carried on SWR/J chromosome 10 seems to be particularly important in AR failure and was confirmed in a partial consomic line. These results establish a genetic basis for AR failure phenotype in mice, with relevance to Sudden Infant Death Syndrome.

Laryngeal constriction during hypoxic gasping and its role in improving autoresuscitation in two mouse strains

Laryngeal closure following hypoxic gasps has been documented, but its efficacy in improving autoresuscitation capacity is unknown. We studied SWR/J mice who normally cannot autoresuscitate and the C57/BLJ strain who can. We evaluated the effects of elevated end-inspiratory lung volume immediately following a gasp. We compared upper airway-intact mice with tracheostomized mice in which the vocal cords are bypassed. We used the techniques of repeated autoresuscitate trials to test autoresuscitation capability. Both SWR/J and C57/BLJ mice could maintain elevated lung volume immediately after a gasp (breath holding). Such breath holding increased autoresuscitation ability in C57/BLJ mice but did not in SWR/J mice. In SWR/J mice, the duration of the breath holds was less than that in the C57/BLJ mice. These findings indicate that gasp-associated breath holding improves autoresuscitation capability during repeated autoresuscitation trials. Also, they show that SWR/J mice have a deficiency in central nervous system mechanisms regulating glottic closure during hypoxic gasping.

Pulmonary arteriolar muscle thickening in sudden infant death syndrome

Pulmonary arteriolar thickening in sudden infant death syndrome has been repeatedly reported but this finding has been challenged. We report a case of a previously healthy 23-day-old infant girl who was witnessed by her parents to die suddenly and unexpectedly. During a routine bottle-feeding, she suddenly began to cry loudly and her face became deep-red and then pale. She became limp and began to gasp. Resuscitation efforts were to no avail. The post-mortem examination, including toxicological studies, screening for inborn errors of metabolism and genetic studies for prolonged Qt syndrome, failed to reveal the cause of death. A more focused study of the lungs showed extensive pulmonary arteriolar thickening. The events in the sudden death of this infant are remarkably similar to deaths in infants with various disorders associated with pulmonary arteriolar thickening. We suggest that this vascular abnormality and associated pulmonary hypertension played a critical role in this infant's death.

Aeromonas veronii biovar sobria bacteraemia with septic arthritis confirmed by 16S rDNA PCR in an immunocompetent adult

An 81-year-old man developed septic arthritis and bacteraemia with Aeromonas veronii biovar sobria. Cultures of the joint wash-out fluid were negative; however, DNA matching that of Aeromonas veronii was identified by 16S rDNA PCR. The patient was successfully treated with a 4 week course of ciprofloxacin. No recognized risk factors were found.

Empyema: the use of broad range 16S rDNA PCR for pathogen detection

BACKGROUND

An increase in the incidence of thoracic empyema in children has been reported. The causative pathogen is often unknown as pleural fluid is frequently sterile at the time of culture. The role of unusual organisms is unclear.

AIMS

(1) To compare the detection of organisms in pleural fluid from children with empyema using a molecular technique (16S rDNA polymerase chain reaction (PCR)) and bacterial culture. (2) To compare the concordance of organisms identified using the two techniques and the influence of prior antibiotic treatment on positive detection rate.

METHODS

Pleural fluid from children admitted with empyema between January 2000 and February 2002 was cultured and additionally analysed using broad range 16S rDNA PCR.

RESULTS

Pleural fluid was cultured from 32 patients, aged 1 month-16 years. Median duration of previous antibiotic therapy was 8 days (range 1-42 days). Six samples were culture positive and 22 were PCR positive. A causal organism was detected by PCR alone, after considering results from the local hospital, in 14 patients. There was complete concordance in organisms cultured and detected by PCR. Additional organisms detected by PCR were predominantly S pneumoniae, S pyogenes, and anaerobes.

CONCLUSIONS

Analysis of pleural fluid by broad range 16S rDNA PCR in addition to culture, increases organism identification in empyema.

Influence of sleep position experience on ability of prone-sleeping infants to escape from asphyxiating microenvironments by changing head position

OBJECTIVE

Several studies have found that back- or side-sleeping infants who are inexperienced in prone sleeping are at much higher risk for sudden infant death syndrome (SIDS) when they turn to prone or are placed prone for sleep compared with infants who normally sleep prone. Moreover, such inexperienced infants are more likely to be found in the face-down position at death after being placed prone compared with SIDS infants who are experienced in prone sleeping. We hypothesized that lack of experience in prone sleeping is associated with increased difficulty in changing head position to avoid an asphyxiating sleep environment.

METHODS

We studied 38 healthy infants while they slept prone. Half of these were experienced and half were inexperienced in prone sleeping. To create a mildly asphyxiating microenvironment, we placed infants to sleep prone with their faces covered by soft bedding. We recorded inspired CO2 (CO2I), electrocardiogram, and respiration, and we videotaped head movements. Also, we assessed gross motor development (Denver Development Scale).

RESULTS

When sleeping prone, with their faces covered by bedding, all infants experienced mild asphyxia as a result of rebreathing. All aroused and attempted escape from this environment. Infants used 3 stereotyped head-repositioning strategies. The least effective was nuzzling into the bedding with occasional brief head lifts. More effective were head lifts combined with a head turn. Some infants, however, could turn only to 1 side, right or left. Infants who were inexperienced in prone sleeping had less effective protective behaviors than experienced infants. Infant age did not correlate with efficacy of protective behaviors. Infants who were experienced in prone sleep had advanced gross motor development compared with inexperienced infants.

CONCLUSION

Infants who are inexperienced in prone sleeping have decreased ability to escape from asphyxiating sleep environments when placed prone. These observations potentially explain the increased risk associated with prone sleep in infants who are inexperienced. The increased occurrence of the face-down position in such infants is also potentially explained. These findings suggest that airway protective behaviors may be acquired through the mechanism of operant conditioning (learning).

Primary aorto/iliac-enteric fistula-report of 6 new cases

The management of patients with vascular-enteric fistulas remains a challenging diagnostic and therapeutic problem for the vascular surgeon. Although fortunately quite a rare cause of gastrointestinal bleeding, reported mortality and amputation rates are very high. Fistulas between major vascular structures and the gastrointestinal tract are classified as either primary or secondary. Primary fistulas occur most commonly between an aortic aneurysm and the distal duodenum, while secondary fistulas occur following erosion of prosthetic material into the bowel following aortic reconstruction. The authors report 6 new cases of primary aortoenteric fistula: A malignant aortoenteric fistula in a patient with advanced metastatic squamous cell carcinoma involving the infrarenal aorta and duodenum, 4 cases of primary aortoenteric fistulas in patients with abdominal aortic aneurysms, and 1 iliac-enteric fistula secondary to a common iliac aneurysm. The diagnosis is often difficult to make, and although it was considered in 4 patients preoperatively, the diagnosis was not made until the time of laparotomy in all of these patients. Three patients were treated with an in-situ vascular graft, 2 others had the distal abdominal aorta oversewn and axillobilateral femoral bypass performed, and in the case involving the malignancy, the patient underwent primary aortic repair owing to the extent of the tumor process prohibiting aortic reconstruction. Three patients had primary closure of the intestine performed, and 3 required bowel resection and primary anastomosis. The overall 30-day mortality rate was 50% as 3 patients died in the early postoperative period and the remaining 3 patients survived to be discharged from hospital. One patient (17%) required bilateral above-knee amputations. Treatment of patients with vascular-enteric fistulas is a difficult problem, often associated with delayed diagnosis and high morbidity and mortality rates. Successful surgical management can be achieved with primary closure of the intestinal tract and an in-situ vascular graft or extraanatomic bypass.

Cotransfection of heme oxygenase-1 prevents the acute inflammation elicited by a second adenovirus

The acute inflammatory response elicited by adenovirus vectors results in loss of gene expression and tissue injury in the target organ. This acute inflammation is now believed to be the major limiting factor for the use of adenovirus vectors in gene therapy. While exploring the level of acute inflammation caused by the adenovirus encoding the gene for the anti-inflammatory enzyme heme oxygenase-1, we discovered that this adenovirus not only did not elicit acute inflammation, but could prevent the inflammation caused by a second adenovirus. Here we describe a new approach to gene therapy, which uses the encoding of the potent anti-inflammatory enzyme heme oxygenase-1 to prevent early host inflammatory responses normally associated with adenovirus vectors.

A national survey of genitourinary medicine clinic attenders provides little evidence of sexual transmission of hepatitis C virus infection

OBJECTIVE

To determine the prevalence and genetic diversity of hepatitis C virus in genitourinary medicine clinic attenders and to assess the extent of sexual transmission of the virus.

METHODS

A cross sectional, unlinked, anonymous survey in 14 genitourinary medicine clinics situated in England, Wales, and Northern Ireland. Serum specimens from genitourinary medicine clinic attenders, retained as part of the Unlinked Anonymous Prevalence Monitoring Programme (UAPMP) serum archive, were tested in small pools, for the presence of antibody to hepatitis C virus (anti-HCV). The main outcome measures were prevalence of antibodies to hepatitis C virus and identification of hepatitis C virus genotypes.

RESULTS

Testing of 17,586 specimens from 1995 showed an adjusted prevalence of anti-HCV in genitourinary medicine clinic attenders of 1.03% (95% CI: 0.89 to 1.16) overall and 0.65% (95% CI: 0.51 to 0.78) among those who did not report injecting drug use. Prevalence in injecting drug users attending genitourinary medicine clinics was 36.9% in both 1995 and 1996. Heterosexual injecting drug users had a higher prevalence of anti-HCV than homosexual/bisexual injectors. The most common hepatitis C genotypes were types 3a and 1a. There was a high degree of concordance between genotype and serotype.

CONCLUSIONS

The low prevalence of anti-HCV in genitourinary medicine clinic attenders who deny injecting drugs suggests that the majority of hepatitis C infections have been acquired in adult life, mostly by injecting drug use, and that the hepatitis C virus is rarely transmitted sexually. The use of needle exchanges may explain the relatively low prevalence observed in the injecting drug users.

A liberalized fasting guideline for formula-fed infants does not increase average gastric fluid volume before elective surgery

Recommended preoperative fasting intervals for infant formula vary from 4 to 8 h. We conducted a prospective, randomized, observer-blinded trial of 97 ASA physical status I and II infants scheduled for elective surgery to determine whether average gastric fluid volume (GFV) recovered from infants formula-fasted for 4 h (liberalized fast, Group L) differed from that recovered from infants allowed clear liquids up until 2 h, but fasted 8 h for formula and solids (traditional fast, Group T). In Group L, 31 of 39 subjects followed protocol and ingested formula 4-6 h before surgery. In Group T, 36 of 58 subjects followed protocol, taking clear liquids 2-5 h before the induction of anesthesia. Thirty subjects had prolonged fasts and were included only in a secondary intent-to-treat analysis. Respective mean age (5.7 +/- 2.3 versus 6.4 +/- 2.4 mo; range, 0.7-10.5 mo), weight (7.5 +/- 1.8 versus 7.5 +/- 1.1 kg), and volume of last feed (4.9 +/- 2.2 versus 4.0 +/- 2.3 oz.) did not vary between Groups L and T. GFV (L: 0.19 +/- 0.38 versus T: 0.16 +/- 0.30 mL/kg) and gastric fluid pH (L: 2.5 +/- 0.5 versus T: 2.9 +/- 1.3) did not vary. For all subjects, GFV (mL/kg) increased with age (Spearman correlation coefficient = +0.23, P = 0.03). Infant irritability and hunger and parent satisfaction were similar between groups. We conclude that average GFV after either a 4- to 6-h fast for infant formula or 2-h fast after clear liquids is small and not significantly different between groups. On the basis of these findings, clinicians may consider liberalizing formula feedings to 4 h before surgery in selected infants.

IMPLICATIONS

Healthy infants aged < or =10.5 mo may drink formula up to 4 h before surgery without increasing gastric fluid volume compared with infants allowed clear liquids up to 2 h and formula 8 h before surgery.

Occurrence and mechanisms of sudden oxygen desaturation in infants who sleep face down

OBJECTIVE

Infants who sleep prone and face down on soft bedding are particularly vulnerable for sudden infant death syndrome. It has been suggested that 1 mechanism of death in this situation involves rebreathing of expired air. Many infants tolerate rebreathing while lying prone face down for long periods with stable saturations. Others occasionally have rapid desaturations and may require intervention to terminate rebreathing. The present study had 3 objectives: 1) to determine the frequency of rapid desaturations in a large group of healthy infants, 2) to elucidate the mechanism of these desaturations, and 3) to determine the timing of these events during periods of rebreathing.

METHODS

We studied respiratory tracings and videotapes of 56 healthy 1- to 6-month-old infants who were sleeping face down and rebreathing on soft bedding in our laboratory. We compared the frequency of desaturations during rebreathing and nonrebreathing periods. We measured respiratory frequency and apnea occurrence before desaturation and nonrebreathing control episodes. We also measured minute ventilation during steady state before desaturation and just before desaturation.

RESULTS

There were 25 desaturation episodes in infants while rebreathing, occurring in 11 (19.6%) of the 56 infants. Episodes were significantly more frequent during rebreathing than during nonrebreathing periods. Three desaturation episodes reached <85%; 2 required intervention to terminate rebreathing. The respiratory frequency was not different between nonrebreathing control and desaturation episodes. Brief apneas were significantly more frequent preceding desaturation than control episodes (44% vs 4%). Just before episodes, there was a transient decrease in minute volume despite increasing inspired carbon dioxide in 3 episodes. There was evidence of partial or complete pharyngeal airway obstruction in 3 episodes. Thirty-six percent of all episodes were immediately preceded by behavioral arousal.

CONCLUSIONS

Rebreathing in prone sleeping infants is associated with an increased frequency of episodic desaturations. Desaturation may result from respiratory pattern changes such as brief apneas often associated with evidence of behavioral arousal or failure to increase ventilation in the face of rising inspired carbon dioxide, also associated with behavioral arousal.

Spontaneous arousals in supine infants while swaddled and unswaddled during rapid eye movement and quiet sleep

OBJECTIVE

Supine sleep is recommended for infants to decrease the risk of sudden infant death syndrome, but many parents report that their infants seem uncomfortable supine. Many cultures swaddle infants for sleep in the supine position. Swaddled infants are said to "sleep better"; presumably they sleep longer or with fewer arousals. However, there have been no studies of the effect of swaddling on spontaneous arousals during sleep. Arousal is initiated in brainstem centers and manifests as a sequence of reflexes: from sighs to startles and then to thrashing movements. Such "brainstem arousals" may progress to full arousal, but most do not.

METHODS

Twenty-six healthy infants, aged 80 +/- 7 days, were studied during normal nap times. Swaddled (cotton spandex swaddle) and unswaddled trials were alternated for each infant. Sleep state (rapid eye movement [REM] or quiet sleep [QS]) was determined by behavioral criteria (breathing pattern, eye movements) and electroencephalogram/electrooculogram (10 infants). Respitrace, submental and biceps electromyogram, and video recording were used to detect startles and sighs (augmented breaths). Full arousals were classified by eye opening and/or crying. Frequencies of sighs, startles, and full arousals per hour were calculated. Progression of events was calculated as percentages in each sleep state, as was duration of sleep state.

RESULTS

Swaddling decreased startles in QS and REM, full arousal in QS, and progression of startle to arousal in QS. It resulted in shorter arousal duration during REM sleep and more REM sleep.

CONCLUSIONS

Swaddling has a significant inhibitory effect on progression of arousals from brainstem to full arousals involving the cortex in QS. Swaddling decreases spontaneous arousals in QS and increases the duration of REM sleep, perhaps by helping infants return to sleep spontaneously, which may limit parental intervention. For these reasons, a safe form of swaddling that allows hip flexion/abduction and chest wall excursion may help parents keep their infants in the supine sleep position and thereby prevent the sudden infant death syndrome risks associated with the prone sleep position.

Physiologic studies on swaddling: an ancient child care practice, which may promote the supine position for infant sleep

OBJECTIVE

The calming effects of swaddling may help infants accept back sleeping and so reduce the risk of sudden infant death syndrome. We hypothesized that swaddling, with minimal leg restraint, would be accepted by postneonatal infants with minimal respiratory effects.

STUDY DESIGN

Postneonatal infants (n = 37)were studied for the introduction of swaddling. Four infants were studied by using traditional swaddling techniques. Swaddle tightness was increased in 13 infants, simulating traditional swaddles. Respiratory variables-respiratory rate, tidal volume, oxygen saturation, heart rate, sigh rate, and "grunting"-were measured.

RESULTS

Hips were flexed and abducted in the swaddle. The majority of infants accepted swaddling while supine, including 78% of infants who slept prone at home. Acceptance decreased with increasing age. With increased swaddle pressure, respiratory rate increased during quiet sleep (P <.05). In rapid eye movement sleep, a slight effect on heart rate was observed (P <.05). Other variables did not change.

CONCLUSIONS

Older infants including usual prone sleepers generally accept a form of swaddling that has minimal respiratory effects. The reintroduction of swaddling, without restricting hip movement or chest wall excursion, combined with supine sleeping, may promote further sudden infant death syndrome reduction.

5-Chlorolevulinate modification of porphobilinogen synthase identifies a potential role for the catalytic zinc

Porphobilinogen synthase (PBGS) is a Zn(II) metalloenzyme which catalyzes the asymmetric condensation of two molecules of 5-aminolevulinate (ALA). The nitrogen of the first substrate ends up in the pyrrole ring of product (P-side ALA); by contrast, the nitrogen of the second substrate molecule remains an amino group (A-side ALA). A reactive mimic of the substrate molecules, 5-chlorolevulinate (5-CLA), has been prepared and used as an active site directed irreversible inhibitor of PBGS. Native octameric PBGS binds eight substrate molecules and eight Zn(II) ions, with two types of sites for each ligand. As originally demonstrated by Seehra and Jordan [(1981) Eur. J. Biochem. 113, 435-446], 5-CLA inactivates the enzyme at the site where one of the two substrate molecules binds, and modification at four sites per octamer (one per active site) affords near-total inactivation. Here we report that 5-CLA-modified PBGS (5-CLA-PBGS) can bind up to four substrate molecules and four Zn(II) ions. Contrary to the conclusion of Seehra and Jordan, we find that the preferential site of 5-CLA inactivation is the A-side ALA binding site. On the basis of the dissociation constants, the metal ion binding sites lost upon 5-CLA modification are assigned to the four catalytic Zn(II) sites. 5-CLA-PBGS is shown to be modified at cysteine-223 on half of the subunits. We conclude that cysteine-223 is near the amino group of A-side ALA and propose that this cysteine is a ligand to the catalytic Zn(II). The vacant substrate binding site on 5-CLA-PBGS is that of P-side ALA. We have used 13C and 15N NMR to view [4-13C]ALA and [15N]ALA bound to 5-CLA-PBGS. The NMR results are nearly identical to those obtained previously for the enzyme-bound P-side Schiff base intermediate [Jaffe et al. (1990) Biochemistry 29, 8345-8350]. It appears that, in the absence of the catalytic Zn(II), 5-CLA-PBGS does not catalyze the condensation of the amino group of the P-side Schiff base intermediate with the C4 carbonyl derived from 5-CLA. On this basis we propose that Zn(II) plays an essential role in formation of the first bond between the two substrate molecules.

Treatment options in hormone-refractory prostate cancer: current and future approaches

Prostate cancer is the second leading cause of cancer mortality among men in Western countries. The initial treatment of advanced prostate cancer is suppression of testicular androgen production by medical or surgical castration, but nearly all men with metastases will develop disease progression. Patients with hormone refractory prostate cancer (HRPC) have a median survival of approximately 18 months and no therapy has yet demonstrated a definitive survival advantage. However, in the past several years, a number of promising new treatment strategies have emerged. One of the most important new treatment strategies involves secondary hormonal manipulation after the failure of primary androgen deprivation. This approach is predicated on the recognition that HRPC is a heterogeneous disease and some patients may respond to alternative hormonal interventions despite the presence of castrate levels of testosterone. Until recently, cytotoxic chemotherapy was felt to be relatively ineffective in the treatment of HRPC. Combination regimens incorporating new active agents have demonstrated significant activity in this setting, renewing interest in the use of chemotherapy to treat HRPC. Recent advances in the understanding of prostate cancer biology have led to the development of drugs directed against precise molecular alterations in the prostate tumour cell. Biologic agents now in development include those capable of altering signal transduction, blocking angiogenesis, inhibiting cell cycle progression, and stimulating apoptosis. In addition, many types of immune therapies are showing promise. Evaluating these agents, and incorporating them into existing regimens, are major goals of ongoing clinical research in advanced prostate cancer.

Cisapride does not prevent postoperative vomiting in children

The peripherally acting prokinetic drug cisapride can overcome opioid-induced gastrointestinal paresis and may thereby eliminate a stimulus for postoperative vomiting. We conducted a prospective, randomized, double-blinded, controlled trial of 96 children undergoing inguinal surgery to determine whether cisapride would reduce the incidence of postoperative vomiting after general anesthesia supplemented with morphine. Group C1 patients (n = 38) received cisapride 0.3 mg/kg orally 1 h before surgery and placebo 6 h later, Group C2 (n = 28) received cisapride both before and after surgery, and Group P (n = 30) received placebo. Mean age (5.0 +/- 2.7 yr) and weight (21.0 +/- 8.6 kg), median pain scores and parent satisfaction scores, and incidence of rescue analgesic administration were similar across groups. Contrary to our hypothesis, incidences of postoperative vomiting in the hospital (32% vs 20%, P = 0.33) and at home (53% vs 46%, P = 0.33) did not vary by treatment group (with [C1 and C2] and without [P] cisapride, respectively). There was a trend toward more severe postoperative vomiting (three or more episodes) in children who received cisapride versus those who did not, both in hospital (6% vs 0%, P = 0.3) and at home (22% vs 8%) (P = 0.13). We conclude that cisapride does not prevent postoperative vomiting in this patient population and speculate that factors other than reduced gastrointestinal motility associated with general anesthesia and opioids are more important determinants of postoperative vomiting.

IMPLICATIONS

Cisapride does not prevent postoperative vomiting in children and may increase its severity.

Endovascular repair of abdominal aortic aneurysm with coexisting renal allograft: case report and literature review

The coexistence of an abdominal aortic aneurysm (AAA) and a pelvic renal allograft is a unique clinical situation. Because of the increased susceptibility of the transplant kidney to ischemic injury, various approaches have been developed to minimize allograft ischemia during open aneurysm repair. Endovascular techniques have the potential advantage in this situation of greatly diminishing renal ischemia time. To our knowledge, this approach has not been reported in this situation. We report a case of a 61-year-old male with a 7.0-cm AAA and a functioning right pelvic transplant kidney. There was an adequate aneurysm neck below the level of the superior mesenteric artery with occluded renal arteries. Successful endovascular repair of the aneurysm was achieved using a bifurcated graft and bilateral iliac extensions. Perfusion to the renal allograft was maintained throughout the procedure except for short periods when the graft was expanded with a balloon. Short-term follow-up reveals successful aneurysm exclusion and no deterioration in renal function. This exciting new approach to this challenging clinical problem is reviewed along with other methods of minimizing renal allograft ischemia.

Genetic diversity and evidence for acquired antimicrobial resistance in Mycobacterium tuberculosis at a large hospital in South India

OBJECTIVE

To assess genetic diversity and drug resistance of Mycobacterium tuberculosis isolates collected at Christian Medical College Hospital (CMCH), Vellore, India, between July 1995 and May 1996.

MATERIALS AND METHODS

Isolates were subjected to IS6110-based restriction fragment length polymorphism (RFLP) analysis and tested for resistance to isoniazid, rifampin, ethambutol, streptomycin, and pyrazinamide, and DNA from selected strains was sequenced in regions associated with drug resistance.

RESULTS

One hundred and one M. tuberculosis isolates were collected from 87 patients with pulmonary tuberculosis. Charts of 69 patients were reviewed for history of tuberculosis illness and treatment. DNA from 29 strains was sequenced in katG, rpoB, and gyrA, and sometimes pncA regions. Analysis by RFLP revealed a high degree of genetic diversity, with no identifiable clusters of infection. Of the strains tested, 51% were resistant to at least one antibiotic, and 43% were resistant to more than one drug. There was a high rate of resistance observed in patients whose charts indicated a history of improperly administered tuberculosis treatment, whereas little drug resistance was observed in patients never previously treated for tuberculosis. Sequencing of genes associated with drug resistance revealed several previously unreported mutations in resistant strains.

CONCLUSIONS

This analysis suggests that the cases of tuberculosis in the sample are largely reactivation of long-standing infections and that the drug resistance among patients in CMCH is largely acquired or secondary rather than attributable to the spread of drug-resistant strains.

Secondary hormonal manipulation of prostate cancer

Prostate cancer is the second leading cause of cancer mortality among men in Western countries. The initial treatment of advanced prostate cancer is suppression of testicular androgen production by medical or surgical castration, but nearly all men with metastases develop disease progression. Patients with hormone-resistant prostate cancer (HRPC) have a median survival of approximately 18 months, and no therapy has yet demonstrated a definitive survival advantage. However, in the past several years, a number of promising new treatment strategies have emerged. One of the most important new treatment strategies involves secondary hormonal manipulation after the failure of primary androgen deprivation. This approach is predicated on the recognition that HRPC is a heterogeneous disease, and some patients may respond to alternative hormonal interventions despite the presence of castrate levels of testosterone.

Role of leukocyte accumulation and oxygen radicals in ischemia-reperfusion-induced injury in skeletal muscle

The role of leukocytes and nonleukocyte-derived reactive oxygen metabolites (ROMs) in reperfusion-induced skeletal muscle injury was determined. Male rats received 2 h no-flow hindlimb ischemia-reperfusion (I/R, n = 6) or were rendered neutropenic via antineutrophil serum (ANS) before I/R (I/R + ANS, n = 5). Oxygen radicals in the absence of neutrophils were tested by administration of dimethylthiourea (DMTU) (I/R + ANS + DMTU, n = 5). Perfused capillaries (CD(per)) and rolling (L(r)), adherent (L(a)), and extravasated leukocytes (L(e)) in the extensor digitorum longus muscle were measured every 15 min during 90 min of reperfusion using intravital microscopy. The vital dyes bisbenzimide (BB) and ethidium bromide (EB) provided direct measures of tissue injury (EB/BB). CD(per) decreased immediately on reperfusion in the I/R and I/R + ANS groups. CD(per) in the I/R + ANS + DMTU group remained at baseline throughout reperfusion. L(a) increased in the I/R group; however, EB/BB was the same between I/R and I/R + ANS groups. Injury in the I/R + ANS + DMTU group did not differ from other groups > or =60 min, after which EB/BB became significantly lower. L(e) did not differ between groups and was highly correlated to tissue injury. The results suggest that L(e) lead to parenchymal injury, and ROMs lead to perfusion deficits during the early reperfusion period after ischemia.

Establishing an endovascular abdominal aortic program--decisions, decisions, decisions: The London Health Sciences Centre experience

The endovascular repair of abdominal or thoracic aortic aneurysms is an alternative approach to conventional repair in the compromised patient. Although the long-term efficacy of these procedures has yet to be proved, there is growing interest among vascular surgeons and interventional radiologists throughout North America and Europe in the more frequent use of this technique. Starting an endovascular program necessitates extensive cooperation of the interdisciplinary vascular team. Decisions regarding patient selection, equipment, supplies, staff education, and the location of the procedure must be based on sound principles. This article demonstrates how a program can be planned, implemented, and evaluated by the use of a "decision tree." The experience of the London Health Sciences Centre will be used as a benchmark in the discussion of relative merits of branch points in program development. The article gives persons contemplating a program a structured process in decision making to avoid potential pitfalls.

Hormonal treatment for prostate cancer

For nearly six decades the preferred primary treatment for advanced prostate cancer has been continuous suppression of testicular androgen production by medical or surgical castration. While androgen deprivation is effective in inducing tumour regression in the large majority of cases, essentially all patients will develop progressive disease. In addition androgen deprivation may be associated with a variety of side effects. Thus, strategies that minimise the use of these agents could potentially lower the morbidity and cost associated with the treatment of advanced prostate cancer. In the era of prostate-specific antigen (PSA) testing, hormonal therapy is being used earlier in the course of the disease when the only evidence of recurrent disease is an elevated PSA. These men may survive for many years and thus have the potential for long periods of exposure to hormonal therapy and its side effects. It has been hoped that the development of alternative hormonal interventions might lead to both enhanced antitumour efficacy as well as improvements in side effect profile.

Kupffer cell-initiated remote hepatic injury following bilateral hindlimb ischemia is complement dependent

Intravital fluorescence microscopy was applied to the livers of male Wistar rats to test the hypothesis that complement mobilization stimulates Kupffer cells and subsequently initiates hepatic injury after hindlimb ischemia/reperfusion (I/R). Following 3 h of limb reperfusion, hepatocellular viability (serum levels of alanine transaminase and cell death via propidium iodide labeling) decreased significantly from levels in sham-operated animals. Inhibition of complement mobilization with soluble complement receptor type 1 (20 mg/kg body wt) and interruption of Kupffer cell function with GdCl(3) (1 mg/100g body wt) resulted in significant hepatocellular protection. Although the effects of hindlimb I/R on hepatic microvascular perfusion were manifest as increased heterogeneity, both complement inhibition and suppression of Kupffer cell function resulted in marked improvements. No additional hepatocellular protection and microvascular improvements were provided by combining the interventions. Furthermore, inhibition of complement mobilization significantly depressed Kupffer cell phagocytosis by 42% following limb reperfusion. These results suggest that the stimulation of Kupffer cells via complement mobilization is necessary but is not the only factor contributing to the early pathogenesis of hepatic injury following hindlimb I/R.

Diversity of hepatitis C virus quasispecies evaluated by denaturing gradient gel electrophoresis

Denaturing gradient gel electrophoresis (DGGE) was used to study the diversity of hepatitis C virus (HCV) quasispecies. Optimized DGGE running conditions were applied to screen for variations in sequences cloned from amplicons originating from the nonstructural 5b (NS5b) gene of HCV in blood of hemophilia patients, intravenous drug users, and blood donors (five specimens from each study group, ca. 40 clones studied per specimen). Clones identified by DGGE as unique were sequenced. NS5b sequence entropy and mean genetic distance in hemophiliacs did not differ significantly from those in the other groups, pointing to a lack of correlation between HCV diversity and the multiplicity of past HCV exposures. DGGE was also applied to investigate variation in the HCV envelope 2/hypervariable region 1 (E2/HVR-1) in serum samples serially taken from two patients during the seroconversion phase of HCV infection. E2/HVR-1 sequence entropy changes were small and not correlated with rising anti-HCV antibody levels, reflecting mutational changes not mediated by antibody selection.

The prevalence and genetic diversity of hepatitis C infection in antenatal clinic attenders in two regions of England

The prevalence and genetic diversity of hepatitis C infection in women attending antenatal clinics in two regions of England was investigated to inform future surveillance and control measures. Women booking into antenatal care are routinely offered a test for immunity to rubella. Serum residues from these tests were unlinked, anonymized and archived as part of the Unlinked Anonymous Prevalence Monitoring Programme (UAPMP). The serum specimens were tested for anti-HCV using a cost-effective pooling strategy. After taking into account differential sampling from the UAPMP serum archive, the adjusted overall prevalence of anti-HCV was 0.43% (95% CI: 0.32-0.53) in London and 0.21% (95% CI: 0.14-0.28) in the Northern and Yorkshire region. Restriction fragment length polymorphism of amplified HCV RNA identified type 3a as the most common HCV genotype in these antenatal women. The prevalence of anti-HCV in antenatal women in the UK is low and consistent with that expected from injecting drug use.

The epidemiology of onychomycosis: possible role of smoking and peripheral arterial disease

BACKGROUND

Onychomycosis is a relatively common condition the aetiology of which appears to be multifactorial, with both genetic and acquired factors being responsible. In our clinical practice we have observed that smokers and individuals with peripheral arterial disease may have an increased prevalence of onychomycosis compared to normal individuals.

PATIENTS AND METHODS

Patients attending a vascular clinic in a hospital were asked about a history of smoking and peripheral arterial disease. The lower extremity was assessed for peripheral arterial disease. Material was obtained from toenails for mycological evaluation.

RESULTS

Two hundred and fifty-four patients (male 146, female 108; age, mean +/- standard error, 66.6 +/- 0.8 years) were enrolled. Abnormal-appearing nails and onychomycosis were present in 49.2% and 22.4% of patients, respectively. Factors associated with onychomycosis included, increasing age (risk odds ratio [ROR] 1.05, P = 0.002), male gender (ROR 1.7, P = 0.09), smoking (packs per day) (ROR 1.9, P = 0.02) and peripheral arterial disease (ROR 4.8, P = 0.02).

CONCLUSIONS

The factors predisposing to the development of onychomycosis are multifactorial. Both smoking (number of packs of cigarettes consumed per day) and peripheral arterial disease are independent predictors of onychomycosis. Awareness of these factors may help in the prevention of onychomycosis and the optimal management of this disease.

Coarctation index: identification of recurrent coarctation in infants with hypoplastic left heart syndrome after the Norwood procedure

Assessment of recurrent coarctation after the Norwood procedure by routine measures is complicated by the unusual physiology caused by the presence of a modified Blalock-Tausig shunt with distal aortic arch obstruction. We present a new index that uses 2-dimensional measurement of the reconstructed aortic arch, which is highly sensitive and specific in identifying recurrent coarctation after the Norwood procedure in children with hypoplastic left heart syndrome.

Inpatient treatment of rheumatoid arthritis with synacthen depot: a double blind placebo controlled trial with 6 month followup

OBJECTIVE

To assess the additional benefit of synacthen depot over standard inpatient care for patients hospitalized with active rheumatoid arthritis (RA).

METHODS

All patients admitted to our unit with active RA without exclusion criteria were invited to participate and randomized to subcutaneous synacthen depot 0.5 mg on alternate days for 2 injections or 2 injections of saline. Patients, staff, and assessors of response were blinded to the intervention. Assessment [OMERACT set, American College of Rheumatology (ACR) global improvement, dose of intraarticular (IA) or intramuscular (IM) methylprednisolone] was performed at admission to hospital, at discharge, and at 3 and 6 months. Oral prednisone use constituted a protocol violation.

RESULTS

Of 137 patients with RA admitted over the period of recruitment, 36 (26%) were enrolled; 31 completed followup. There were no between-group differences in the change from admission of any individual disease activity measure at any time point. However, using a rigorous global response measure (ACR 50%), a difference was detected in favor of synacthen depot at discharge (52.6% of the intervention group improved vs. 17.6% of controls; p = 0.029, number-needed-to-treat 2.86). Patients treated with synacthen depot showed a trend toward more IA or IM corticosteroid between discharge and 3 months (mean dose 56 vs. 31 mg; p = 0.19) and a trend toward more patients requiring a change in slow acting antirheumatic drug after discharge (4 vs. 1; p = 0.27).

CONCLUSION

There is some additional benefit of synacthen depot in the hospital treatment of RA, but the effect is lost by 3 months, with a suggestion of rebound worsening in these patients. We postulate that oversuppression of corticotrophin releasing hormone by exogenous adrenocorticotrophic hormone in patients who already have a hypothalamic deficit may contribute to the rebound worsening of disease activity seen in these patients.

Cytokines contribute to early hepatic parenchymal injury and microvascular dysfunction after bilateral hindlimb ischemia

PURPOSE

Hepatic dysfunction may contribute to death from multiple organ dysfunction after abdominal aortic surgery. Several factors are likely responsible, and the purpose of this study was to determine whether the cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin 1 (IL-1) are involved in initiating this remote hepatic injury.

METHODS

In a normotensive rat model of 4-hour bilateral hindlimb ischemia/reperfusion (I/R), we measured systemic TNF-alpha and IL-1 levels throughout the I/R period. Rats were randomly assigned to either the 3-hour control group, the 3-hour I/R group, or the I/R group with administration of a polyclonal antibody (PAb) to TNF-alpha (I/R + TNF-alpha PAb). Direct evidence of lethal hepatocyte injury through the labeling of nuclei by propidium iodide (per 10(-1)mm(3)) and altered microvascular perfusion were assessed by using intravital microscopy.

RESULTS

Systemic TNF-alpha peaked at 83.97 pg/mL (P <.05, n = 5) at 30 minutes of reperfusion and returned to baseline in 60 to 90 minutes. No significant change in systemic IL-1 was detected (P <.05, n = 4). Alanine aminotransferase increased 2.5-fold in the I/R group through 3 hours of reperfusion (P <.05, n = 4), and TNF-alpha PAb did not attenuate this alanine aminotransferase increase (P <.05, n = 6). Lethal hepatocyte injury increased by 8-fold in the I/R group compared with the control group (P <.05, n = 5), whereas TNF-alpha PAb significantly reduced this injury (P <.05, n = 4). No regional differences in injury were noted within the acinus. Total perfusion within the microvascular unit did not drop; however, significant flow heterogeneity was observed. The proportion of continuously perfused sinusoids declined in the I/R group after 3 hours of reperfusion in both periportal (62.0 +/- 2.2, P <.05) and, to a lesser, although significant, degree, in the pericentral regions (73. 2 +/- 1.73, P <.05).

CONCLUSION

By scavenging extracellular TNF-alpha with a PAb, we provide direct evidence that TNF-alpha contributes to, but is not solely responsible for, early remote hepatocellular injury and microvascular dysfunction. The administration of TNF-alpha PAb reduced lethal hepatocyte injury in both regions of the acinus and also improved perfusion in the periportal region (76.8 +/- 5.41, P <.05), but not in the pericentral region. This suggests that TNF-alpha released during reperfusion mediates early remote hepatocellular injury and microvascular dysfunction after a remote ischemic insult.

The effect of luminol on presumptive tests and DNA analysis using the polymerase chain reaction

This study was designed to test the following factors involved with processing luminol treated bloodstained evidence: 1) The reactivity of other presumptive chemical color tests, phenolphthalin (PT) and tetramethylbenzidine (TMB), following the application of the light emitting luminol presumptive test. 2) The effect of different cleanings of various bloody substrates on the luminol test. 3) The effect of different cleanings of various bloody substrates on the ability to obtain DNA suitable for PCR testing. 4) The ability to extract DNA from luminol treated bloodstained substrates using three extraction techniques. 5) The effect of spraying washed and unwashed bloodstains on various substrates with luminol on the ability to correctly type the DNA using PCR. Our findings indicated that luminol did not adversely effect the PCR testing and did not interfere with the PT and TMB presumptive tests for blood. It was determined that the substrate and the method of cleaning were the major factors affecting DNA yield and the ability to type the bloodstains using PCR based technologies.

Microcirculatory perfusion deficits are not essential for remote parenchymal injury within the liver

A normotensive model of hindlimb ischemia-reperfusion in Wistar rats was used to test the hypothesis that microvascular perfusion deficits contribute to the initiation of remote hepatic injury during a systemic inflammatory response. Animals were randomly assigned to one of three groups: 4 h of ischemia with 6 h of reperfusion (I/R-6; n = 4), 4 h of ischemia with 3 h of reperfusion (I/R-3; n = 5), or no ischemia (naive; n = 5). With intravital fluorescence microscopy, propidium iodide (PI; 0.05 mg/100 g body wt) was injected for the in vivo labeling of lethally injured hepatocytes (number/10(-1) mm(3)). PI-positive hepatocytes increased progressively over the 6-h period (naive 32.9 +/- 7.8 vs. I/R-3 92.8 +/- 11.5 vs. I/R-6 232 +/- 39.2), with no difference between periportal and pericentral regions of the lobule. Additionally, a significant decrease in continuously perfused sinusoids (naive 70.0 +/- 1.5 vs. I/R-3 65.0 +/- 1.0 vs. I/R-6 48.8 +/- 0.9%) was measured. Regional sinusoidal perfusion differences were only observed after 3 h of limb reperfusion. Indirect measures of hepatocellular injury using alanine transaminase levels support the progressive nature of hepatic parenchymal injury (0 h 57.8 +/- 6.5 vs. 3 h 115.3 +/- 20.7 vs. 6 h 125.6 +/- 19.5 U/l). Evidence from this study suggests that remote hepatic parenchymal injury occurs early and progresses after the induction of a systemic inflammatory response and that microvascular perfusion deficits are not essential for the initiation of such injury.

Initiation of remote hepatic injury in the rat: interactions between Kupffer cells, tumor necrosis factor-alpha, and microvascular perfusion

Severe trauma may initiate a systemic inflammatory response, which in turn may result in remote organ injury. After limb ischemia/reperfusion (I/R), intravital fluorescence microscopy was applied to the livers of normotensive rats to investigate the initiation of remote injury to the liver. Additionally, we determined whether Kupffer cell activation and tumor necrosis factor-alpha (TNF-alpha) were involved, via perfusion deficits, in such injury. TNF-alpha, measured by immunoassay, peaked at 30 minutes of reperfusion, but returned to baseline within 60 minutes. Limb I/R resulted in significant increases to global hepatocellular injury measured by alanine transaminase (ALT) and lethal hepatocyte injury as seen with intravital fluorescence microscopy. Although the number of perfused sinusoids went unchanged, a significantly augmented perfusion heterogeneity was measured. After 1.5 hours of reperfusion, both TNF-alpha and Kupffer cells were shown to contribute to global hepatocellular injury (e.g., ALT). After 3 hours, TNF-alpha was no longer essential for this injury, suggesting that some other mechanism(s) activated Kupffer cells and initiated hepatocellular injury. Using propidium iodide and fluorescence microscopy, we found that both TNF-alpha and Kupffer cell activation were necessary to drive hepatocytes toward lethal injury. No additional benefits were observed with a combination of TNF-alpha inhibition and Kupffer cell suppression. These results not only implicate both Kupffer cells and TNF-alpha in the initiation of remote hepatic injury, but suggest that sinusoidal perfusion deficits are not essential for the initiation of such injury. Other mechanism(s) are likely involved in the pathogenesis of remote hepatic parenchymal injury.

The most prevalent hepatitis C virus genotypes in England and Wales are 3a and 1a

Hepatitis C virus (HCV) genotypes were assigned to 567 individuals by restriction fragment length polymorphism analysis of the 5' noncoding region of the HCV genome following reverse transcription-polymerase chain reaction. The groups of individuals in this study included hemophilia patients, injecting drug users (IDUs), blood donors, antenatal patients, those attending genitourinary medicine (GUM) clinics, and patients with chronic liver disease, all from England and Wales. The majority of HCV infections were types 1a (32%), 1b (15%), or 3a (37%). The genotype distribution in individual groups was similar to the overall genotype distribution except for hemophilia patients, in whom the frequencies were 1a (39%), 1b (23%), and 3a (21%). With the exception of hemophilia patients, subpopulations in England and Wales appear to share common modes of HCV transmission. There is a need for continued surveillance to monitor the spread of possibly more virulent or drug-resistant HCV genotypes.

The effect of mannitol versus dimethyl thiourea at attenuating ischemia/reperfusion-induced injury to skeletal muscle

OBJECTIVE

Mannitol is used as a treatment for skeletal muscle ischemia/reperfusion (I/R) injury in humans, despite the fact that its effectiveness in vivo is still disputed. The purpose of this study was to determine the efficacy of mannitol in attenuating I/R injury at the microcirculatory level.

METHODS

The study was designed as an experimental study with male Wistar rats. The main outcome measures were intravital microscopy, which was used to measure capillary perfusion, capillary and venular red blood cell velocity (VRBC), and leukocyte-endothelial interactions in the extensor digitorum longus muscle of the rat hind limb before and after ischemia. In addition, tissue injury was assessed during reperfusion with the fluorescent vital dyes bisbenzimide and ethidium bromide. Dimethyl thiourea (DMTU), a highly effective therapeutic agent of experimental I/R injury, was used as a positive control.

RESULTS

No-flow ischemia (2 hour) resulted in a 40% drop in capillary perfusion, a decline in capillary and venular VRBC, and increased leukocyte venular adherence and tissue infiltration. Tissue injury increased to a constant level during reperfusion. Mannitol attenuated capillary malperfusion during the first 60 minutes of reperfusion and prevented a decline in capillary VRBC. However, mannitol did not reduce tissue injury or leukocyte adherence and infiltration during reperfusion. By comparison, DMTU not only prevented the perfusion deficits and the increases in leukocyte venular adherence and tissue infiltration but significantly reduced the magnitude of tissue injury.

CONCLUSION

Our findings suggest that mannitol may be of limited value for the prevention of early reperfusion-induced injury after no-flow ischemia in skeletal muscle. By comparison, DMTU was highly efficacious by not only reducing microvascular perfusion deficits but by also reducing leukocyte-endothelial cell interactions and the incidence of cellular injury.