Paradoxical cerebral embolisation. An explanation for fat embolism syndrome

Fat embolism occurs following fractures of a long bone or arthroplasty. We investigated whether paradoxical embolisation through a venous-to-arterial circulation shunt (v-a) could lead to cerebral embolisation during elective hip or knee arthroplasty. Transcranial Doppler ultrasound (TCD), following the intravenous injection of microbubble contrast, identified the presence of a shunt in 41 patients undergoing hip (n = 20) or knee (n = 21) arthroplasty. Intra-operative cerebral embolism was detected during continuous TCD monitoring. Of the 41 patients, 34 had a v-a shunt of whom 18 had an embolism and embolism only occurred in patients with a shunt (p = 0.012). Spontaneous and larger shunts were associated with a greater number of emboli (rs = 0.67 and rs = 0.71 respectively, p < 0.01). Observations in two patients with large spontaneous shunts revealed 368 and 203 emboli and unexplained post-operative confusion and pancreatitis. Paradoxical cerebral embolisation only occurred in patients with a shunt and may explain both postoperative confusion and fat embolism syndrome following surgery.

Carotid endarterectomy improves cognitive function in patients with exhausted cerebrovascular reserve

OBJECTIVE

To investigate changes in cognitive function following carotid endarterectomy (CEA).

DESIGN

Prospective study with controls.

METHODS

CEA patients (n=159) were compared to a urology surgery control group (n=20). In CEA patients cerebrovascular reserve (CVR) was measured preoperatively. During surgery emboli and blood flow velocity in the middle cerebral artery were measured by transcranial Doppler (TCD) and cerebral oxygen saturation (CsO2) by near infrared spectroscopy. Cognitive function was measured preoperatively and at 5 days and 8 weeks postoperatively using a standardised computer battery of tests.

RESULTS

Only 8% of patients had normal CVR bilaterally. The median number of emboli during CEA was 12 (range 0-181). On carotid clamping, TCD velocity fell a median of 41% and cerebral oxygen saturation by 5%. Attention deteriorated compared to controls 5 days following CEA (p=0.003) and this deterioration was related to the rise in TCD velocity on declamping (r=-0.3, p=0.002). Median attention reaction times improved significantly by 8 weeks (p=0.001) especially in patients' with severely impaired CVR before surgery (p=0.02).

CONCLUSIONS

Attention improved at 2 months following CEA in patients with impaired CVR. CEA may offer more than reduced stroke risk to patients with impaired CVR.

Risk of hepatitis C virus transmission from patients to surgeons: model based on an unlinked anonymous study of hepatitis C virus prevalence in hospital patients in Glasgow

BACKGROUND

The risk of a surgeon acquiring the hepatitis C virus (HCV) through occupational exposure is dependent on the prevalence of HCV infection in the patient population, the probability of a percutaneous injury transmitting HCV, and the incidence of percutaneous injury during surgery.

AIMS

To estimate the prevalence of HCV infection in the adult surgical patient population in North Glasgow and thereafter estimate the risk of HCV transmission to surgeons through occupational exposure.

METHODS

The prevalence of HCV infection was estimated through the unlinked anonymous testing of samples from male surgical patients, aged 16-49 years, in two North Glasgow hospitals from 1996 to 1997, and adjusting these data for age and sex. Using published estimates of the incidence of percutaneous injury during surgery and percutaneous injury transmitting HCV, the risk of occupational transmission of HCV to surgeons was then derived.

RESULTS

The estimated prevalence of anti-HCV infection for all adult patients in the two hospitals combined was 1.4% (cardiothoracic/cardiology 0.8%, orthopaedics/rheumatology 1.4%, general surgery/ENT 2.0%). The estimated probability of HCV transmission from an HCV infected patient to an uninfected surgeon was 0.001-0.032% per annum (0.035-1.12% risk over a 35 year professional career).

CONCLUSIONS

The risk of an individual surgeon acquiring HCV through occupational exposure is low, even in an area with an extremely high prevalence of HCV among its injecting drug using population. Surgeons however should be encouraged to observe universal precautions and present for assessment after needlestick injuries to protect themselves and their patients from this insidious infection.

Age-related differences in movement representation

Repetitive movements have been used as motor activation tasks in the investigation of various neurological disorders. To determine the importance of an age-matched control group in such studies we investigated whether there are significant age-related changes in the pattern of cortical activation seen during simple repetitive movements. Sixteen right-handed healthy subjects were studied-8 young and 8 old. Functional magnetic resonance images were acquired while subjects performed a motor task or a nonmovement rest condition. Two continuous motor tasks, index finger abduction/adduction and wrist extension/flexion, were performed by each hand, paced using a metronome. The fMRI data were processed and analyzed with SPM '99. For the between-group comparisons, for each motor task, contralateral primary sensorimotor cortex and premotor cortex had significantly greater activation in the Young group and caudal supplementary motor area had significantly greater activation in the Old group. Ipsilateral sensorimotor cortex was more significantly activated in the Old group for index finger motor tasks of both hands. All noted differences in the Old group were more prominent for the index finger movement and most prominent when using the nondominant hand. In conclusion, there are significant age-related differences in the activation pattern associated with repetitive movements. This may represent compensatory recruitment of motor cortical units in the older subjects as larger differences are noted in the older group during the more difficult motor tasks, those of isolated finger movement and nondominant hand use. This study has important implications for functional imaging experiments of neurological disorders in older subjects.

Calf compartment pressures in the Lloyd-Davies position: a cause for concern?

Lower limb compartment syndrome is a rare consequence of surgery where the lithotomy position is maintained for several hours. The aim of this study was to observe the effect of the lithotomy position on lower limb compartment pressure and blood flow to the lower limb in surgical patients having colorectal procedures. We prospectively studied 23 patients undergoing colorectal surgery requiring the lithotomy position and recorded lower limb compartment pressure, and the blood pressure in the upper and lower limbs. The lithotomy position led to a significant (p < 0.001) fall in blood pressure to the lower limb from 87 (SD 16) mmHg to 67.9 (SD 12) mmHg and a significant (p < 0.001) rise in lower limb compartment pressure from 13 (SD 7) mmHg to 31 (SD 12) mmHg. These two effects compromise blood flow to the lower limb in long surgical procedures where the lithotomy position is required. Intermittently lowering the legs and restoring blood flow may prevent compartment syndrome developing.

Trends in HCV prevalence among injecting drug users in Glasgow and Edinburgh during the era of needle/syringe exchange

In 1998, we reported that anti-HCV prevalence among injectors from Glasgow had declined between 1990 and 1995. We set out to ascertain if the anti-HCV prevalence among injectors from Edinburgh had declined similarly during this period and if there had been any trend in prevalence among injectors from both cities since 1995. Residual sera from both cities' injecting drug users who had undergone named HIV testing were identified, linked to age band and gender information and tested anonymously for anti-HCV. Among Edinburgh's injectors, significant (p < 0.0001) decreases in anti-HCV prevalence from 69% (1989/90) to 13% (1997) and from 80% (1989/90) to 54% (1997) were seen in those aged < 25 y and > or = 25 y, respectively. Among Glasgow's injectors, a significant (p < 0.0001) decrease in prevalence from 91% (1990) to 43% (1997) was seen only among those aged < 25 y. Of both cities' 15-19 y olds, sampled during 1995-97, 17% (24/139) were anti-HCV-positive. The findings suggest that the incidence of HCV among young injectors continued to decrease during the 1990s--the era of needle/syringe exchange and other interventions--but is still too high. Further investigative and preventive work is required.

Multiple sclerosis presenting to the dental practitioner: a report of two cases

In this paper, two patients are described who presented with trigeminal neuralgia which turned out to be an early symptom of multiple sclerosis. General dental practitioners need to be aware of the possible causes for atypical facial pain, especially in patients under 40 years.

Sediment-associated tri-n-butyltin chloride and its effects on osmoregulation of freshwater-adapted 0-group European flounder, Platichthys flesus (L.)

The disruption of osmoregulatory processes was examined in European flounders exposed to environmental concentrations (150 ng TBTCl g(-1) dry weight sediment) of sediment-associated tri-n-butyltin chloride (TBTCl), by using radiotracers to measure changes in hydromineral fluxes and water balance. The water permeabilities of TBTCl-exposed fish varied during the course of the experiment and were significantly lower than those of the corresponding controls that did not change significantly with time. It was found that the maximum decrease in water permeability of TBTCl-exposed fish occurred after 14 days; thereafter there was an increase towards control values. However, there was a differential reduction of the diffusional (P(d)) and osmotic (P(os)) permeability coefficients, where the former decreased more rapidly than the latter, reflecting the reduction of diffusional membrane permeability and the increasing importance of osmotic permeability. In fish exposed to TBTCl sodium efflux and drinking rates were significantly increased but Na(+)/K(+)-ATPase activities and urine production rates were not affected. The effects of TBTCl exposure are also manifested at the level of the whole organism by a reduction in the increase of the body length of exposed fish, when compared to controls. It was concluded that tributyltin-n-chloride in sediments is capable of significantly disrupting the osmoregulatory functions of a benthic estuarine fish, at concentrations found in the sediments of Southampton Water and the River Itchen.

A method to detect the incidence of hepatitis C infection among injecting drug users in Glasgow 1993-98

OBJECTIVES

To determine the incidence of HCV infection in a selected population of Glasgow injectors during the mid-1990s, using a retrospective cohort design.

METHODS

Unlinked anonymous anti-HCV testing was undertaken on serum residues collected from injecting drug users (IDUs) having two or more voluntary named HIV tests between 1993 and 1998.

RESULTS

Seventy-seven percent (164/212) of IDUs had detectable HCV antibody in their first specimen collected. Of the 44 IDUs who were initially HCV seronegative and had a subsequent specimen available for testing, 11 (25%) seroconverted, giving an estimated incidence of 28.4 per 100 person-years (95% CI 15.7-51.2); the incidence of infection was greatest amongst older males.

CONCLUSION

This study provides evidence of continuing transmission of HCV among Glasgow IDUs during an era of interventions to prevent the spread of bloodborne infections in this population and demonstrates the application of the unlinked anonymous testing approach to gauge incidence rather than prevalence of infection.

Marfan syndrome caused by a mutation in FBN1 that gives rise to cryptic splicing and a 33 nucleotide insertion in the coding sequence

We have studied a patient with Marfan syndrome whose mutation was not detected by heteroduplex analysis. Primary cultured patient fibroblasts were metabolically labelled and found to secrete fibrillin-1 defectively when compared with an age-matched control. Sequencing of patient cDNA, isolated by reverse transcription-polymerase chain reaction of patient fibroblast RNA, detected a 33-bp insertion. The reading frame of the mutant allele was maintained and predicted the insertion of 11 amino acids at the beginning of calcium-binding epidermal growth factor-like domain 29. Direct sequencing of genomic DNA detected a heterozygous G+1-->A transversion in intron 46 of FBN1. The 11 amino acid insertion was the consequence of the usage of a cryptic splice site 33-bp downstream of the mutation. This is the first reported case of a splicing defect in FBN1 leading to the production of a full-length fibrillin-1 transcript containing a large amino acid insertion.

The effects of sediment-associated triorganotin compounds on the gills of the European flounder, Platichthys flesus (L.)

The effects of exposure to sediment-associated tri-n-butyltin chloride (TBT) and triphenyltin chloride (TPhT) were examined in the euryhaline European flounder, Platichthys flesus (L.). The effects were quantified by measuring the changes in sodium efflux, Na(+)/K(+)-ATPase activity and the numbers, areas and distribution of chloride cells in the gills of freshwater-adapted fish, following a rapid transfer to seawater. After transfer, the Na(+)/K(+)-ATPase activity and the sodium efflux significantly increased in both the TPhT and control groups but not in the TBT group. However, Na(+)/K(+)-ATPase activity and the sodium efflux in the TPhT group had returned to pre-salinity transfer levels by day 15 after the initial exposure to TPhT. Morphological changes in the numbers and areas of chloride cells, known to be associated with seawater adaptation, took place in the control group, i.e. there was a significant reduction in the number of lamellar chloride cells accompanied by an increase in the number of interlamellar chloride cells. There was a reduction in the numbers of lamellar chloride cells in the TBT-exposed group following transfer to seawater but the mean number was significantly higher than the control group by the end of the experiment. In the TPhT-exposed group, the reduction was not significantly different to that seen in the control group. By the end of the experiment, both organotin-exposed groups had significantly lower mean numbers of interlamellar chloride cells than the control group. Before transfer to seawater, the mean areas of lamellar and interlamellar chloride cells of all three groups were not significantly different. On transfer, the mean areas of lamellar chloride cells in the control group became significantly smaller than the mean areas of the organotin groups. There was no significant difference in the mean areas of interlamellar chloride cells in the control and TBT groups between the start and finish of the experiment but there was a significant increase in the mean area of TPhT-treated animals at the end of the experiment when compared to the control group. The results presented in this study lead to the conclusion that tri-n-butyltin chloride and triphenyltin chloride in sediments are capable of significantly disrupting both the physiological as well as morphological components of ionic regulatory functions of an estuarine fish, at concentrations currently found in estuarine sediments.

Partner notification in HIV-1 infection: a population based evaluation of process and outcomes in Scotland

OBJECTIVES

To evaluate the process and outcomes of HIV partner notification (PN) activity in Scotland.

DESIGN

Retrospective population based study.

SUBJECTS

114 adults newly diagnosed with HIV infection (index patients) in Scotland between September 1995 and August 1996.

SETTING

Healthcare settings in which all 114 new HIV diagnoses were made: 42 (37%) from genitourinary medicine; 32 (28%) infectious diseases; 18 (16%) general practice; and 22 (19%) from other sites.

MAIN OUTCOME MEASURES

Number of partners notified and tested up to 9 months after initial diagnosis.

RESULTS

Of 114 index patients (IPs), information on current partners was available for 102 (89%). PN was not appropriate for 47 of the 102 IPs. The remaining 55 IPs identified 63 current partners at risk, of whom 51 were notified: 44 underwent HIV testing, which yielded 11 new HIV positive diagnoses. Information on previous partners was available for only 56 IPs (49%). PN was not appropriate for 30 of the 56 IPs; the remaining 26 IPs identified 46 previous partners at risk, of whom 12 were notified: four were tested, but yielded no new diagnoses.

CONCLUSIONS

Notification of current partners was performed well and was an effective strategy for identification of HIV positive individuals at a presymptomatic stage. Notification of previous partners was limited. Partner notification was attempted in a wide range of healthcare settings. Given the clinical effectiveness of antiretroviral therapy, partner notification as a tool towards early diagnosis of HIV disease deserves renewed attention.

Hepatitis C virus among high and low risk pregnant women in Dundee: unlinked anonymous testing

OBJECTIVE

To determine the prevalence of the hepatitis C virus among pregnant women, to gauge the non-injecting, particularly sexual, risk of them being hepatitis C virus infected and to assess the potential impact of selective antenatal screening.

POPULATION

Antenatal clinic attenders and women undergoing termination of pregnancy in 1997.

SETTING

Ninewells Hospital, Dundee.

DESIGN

Unlinked anonymous hepatitis C virus antibody testing of residual sera from specimens sent to the virus laboratory for routine serological testing. The results were linked to non-identifying risk information.

RESULTS

Overall anti-hepatitis C virus prevalence was 0.6% (23/3,548). Prevalences among injecting drug users, non-injectors who had a sexual partner who injected, and those with neither risk respectively were 41% (7/17), 15% (5/33) and 0.3% (11/3,498). Relative risks for being an injector and a sexual partner of an injector respectively were 131 (95% CI 58-297) and 48 (95% CI 5-32). It is estimated that one of the 18 antenatal clinic attenders gave birth to an infected child.

CONCLUSION

Findings suggest that non-injecting partners of injectors may be at considerable risk of acquiring hepatitis C virus sexually. Efforts to promote the use of condoms among injectors and their sexual partners should be increased. Selective anti-hepatitis C virus screening of women who reported high risk behaviour would have failed to detect half the cases. Research to gauge the views of women of childbearing age on anti-hepatitis C virus testing is required.

A retrospective review of pregnancy outcome after misoprostol (prostaglandin E1) induction of labour

This retrospective study looked at the outcome of using 50-100 micrograms misoprostol once daily to induce labour compared to the outcome of the overall patient population delivered during the same period (1994-1996). During that period 11,255 patients were delivered and 1037 (9.2%) were induced with misoprostol. Results showed a significantly lower mean Caesarean section rate: 9.3% for the misoprostol group versus 13.3% for the overall population (p = 0.002, Odds Ratio (OR) 0.67, 95% CI 0.53, 0.83). The abruption rates were not significantly different: 0.8% for misoprostol versus 0.4% (p = 0.09, OR 1.86, 95% CI 0.81, 4.09). There was more postpartum haemorrhage in the misoprostol group: 5.6% versus 3.5% (p = 0.0006, OR 1.63, 95% CI 1.22, 2.19); a higher incidence of Apgar scores less than 6 at one minute 10.2% versus 7.9% (p = 0.0093, OR 1.33, CI 1.06, 1.65) but not at five minutes 2.9% versus 2.4% (p = 0.674, OR 1.09, CI 0.73, 1.61) and a higher perinatal mortality rate 55/1000 versus 16.3/1000 (p = 0.00, OR 3.5, 95% CI 2.55, 4.80). The rate remained higher but not significantly so when a correction was made to eliminate the high number of intrauterine deaths induced with misoprostol 18/1000 versus 16.3/1000 (p = 0.69, OR 1.11, 95% CI 0.66, 1.84). There were no cases of uterine rupture in either group. In conclusion, there was a significantly lower Caesarean section rate among patients who had once daily misoprostol induction of labour. Close monitoring of the foetus, in patients with misoprostol induction, is needed to detect foetal distress and prophylaxis against postpartum haemorrhage is still mandatory.

Prevalence of antibodies to hepatitis C virus, HIV and human T-cell leukaemia/lymphoma viruses in injecting drug users in Tayside, Scotland, 1993-7

The prevalence of blood-borne viruses in injecting drug users (IDUs) in Tayside, Scotland was determined by testing serum samples from IDUs who underwent attributable HIV antibody testing during 1993-7. The prevalence of antibodies to HIV was 29/802, (3.6%); to hepatitis C virus (HCV) 451/691, (65.3%); and to human T-cell leukaemia/lymphoma viruses type 1 and 2 (HTLV) 0/679, (0.0%). The prevalence of HIV and HCV antibodies were higher in subjects over the age of 25 (P = 0.03 and P = 0.001, respectively). During 1993-7 the prevalence of HCV fell only in younger female IDUs (P < 0.01). HIV prevalence has declined dramatically since 1985, when a rate of 40% was recorded in similar populations. Harm reduction measures have failed to control HCV the spread of infection among IDUs in Tayside, as indicated by the high proportion of antibody positive IDUs, particularly males under the age of 25. Future studies should address the nature and effective reduction of continuing risk taking among IDUs in Tayside.

Response of haemocyte lysosomes to bacterial inoculation in the oysters Ostrea edulis L. and Crassostrea gigas (Thunberg) and the scallop Pecten maximus (L)

Data are presented that demonstrate the application of the neutral red retention assay (NRR) to monitor the effects of a bacterial inoculation on the haemocyte lysosomes of the European flat oyster Ostrea edulis, Pacific oyster Crassostrea gigas and scallop Pecten maximus. Bivalves were acclimated to three temperature regimes (5, 15 and 25 degrees C), at constant salinity for 7 days in the laboratory. Once baseline responses to acclimation temperature had been established, the effects of an in vivo inoculation on haemocyte lysosomal stability were assessed using the NRR assay. Lysosomal membrane stability was reduced in the presence of bacteria for all three species of bivalve, but destabilisation of C. gigas haemocyte lysosomes appeared to be most sensitive to the presence of the bacterium Listonella anguillarum. For all three bivalve species, the reduction in lysosomal stability appeared to be proportional to the growth of the bacterial inoculate. Using appropriate controls, the NRR assay was demonstrated to have great potential as a tool with which to make rapid initial assessments of the immune status of bivalve molluscs.

Organotin and osmoregulation: quantifying the effects of environmental concentrations of sediment-associated TBT and TPhT on the freshwater-adapted European flounder, Platichthys flesus (L.)

Chronic (5 weeks) exposure of freshwater-adapted European flounder, Platichthys flesus (L.), to environmental concentrations of sediment-associated tri-n-butyltin chloride (TBTCl) and triphenyltin chloride (TPhTCl) caused significant changes to hydromineral fluxes and membrane permeability, mechanisms that maintain osmotic homeostasis. The half-time of exchange of tritiated water (THO) in TBTCl- and TPhTCl-exposed fish was significantly increased during the first 2 weeks of the experiment and then decreased steadily, eventually reaching the level that the control group had constantly maintained throughout the experiment. This change in apparent water permeability was accompanied by a significant decrease in diffusional water flux across the membranes. Passive Na(+)-efflux across the gills was increased significantly but effluxes in the control group were near constant over the same time span. Drinking rates in the organotin groups increased significantly while the rate of urine production did not change. This lead to an increased net water balance in the organotin groups and consequently to a significant reduction of the blood osmolality of both organotin groups when compared to a control. There would appear to be a metabolic cost attached to the changes produced by exposure to environmental levels of organotin compounds which are manifested as a minimal increase in body length compared to the controls.

Working patterns of trainee anaesthetists in the UK: results of a national postal survey

The 'New Deal' restrictions on junior doctors' hours have major implications for the staffing of anaesthetic departments and the provision of adequate training. The results of a national postal survey demonstrate a decline in traditional on-call arrangements, especially in hard-pressed work sectors such as intensive care. A substantial number of anaesthetic departments have still completely to satisfy the hours restrictions in many work sectors. Many departments experience recruitment difficulties and express concern about both service and training issues.

Products for Alzheimer's self-stimulatory wanderers

The objective of this study was to develop a variety of sensory stimulation products for the behavioral intervention of patients with Alzheimer's type dementia. Many caregivers have relied on physical and chemical restraints as the primary method of patient intervention due to the lack of appropriate dementia management products. This significantly lowers the sufferer's quality of care and life. As the age group most susceptible to Alzheimer's disease (65 and older) is the fastest growing segment of our society, an appropriate care solution must be sought. The specific aim of this study was to develop products that are sensory satisfying for the Alzheimer's patient that exhibits self-stimulatory wandering behavior. Sensory satisfying objects for product development would be determined through structured observations of self-stimulatory wanderers in an institutionalized setting. Variations of product design and mounting would be pursued in order to develop products that are not only safe and effective for patient use, but are easy for the caregiver to implement and maintain. Such products would have widespread commercial application in both the institutional and private care settings such as nursing homes, adult day care facilities, Alzheimer's care facilities, convalescent homes, mental health institutions, and assisted-living facilities.