Does indermil glue improve success rates in myringoplasty? Interim analysis of a prospective trial

The success rates of myringoplasty vary in the literature from 65 to 97.5 percent. Various reasons for failure are cited, one being failure of the graft to act as an adequate scaffold due to its falling away from the edge of the perforation. The potential role of adhesives in myringoplasty has been described but not objectively assessed. A group of 15 patients with a perforation of the tympanic membrane present for at least 6 months was prospectively recruited. All patients underwent myringoplasty using underlayed temporalis fascia. In each case the graft was spot welded to the edge of the perforation using Indermil (n-butyl cyanoacrylate) glue. At mean 7.7 months post operatively 14 grafts are intact (93%) and all patients have audiometric improvement (p < 0.01). These results are better then those from national audit statistics in the UK using conventional methods suggesting this technique is very promising. The technique and results are described.

Pulmonary embolism from pulse-spray pharmacomechanical thrombolysis of clotted hemodialysis grafts: urokinase versus heparinized saline

PURPOSE

To compare the frequency and extent of pulmonary embolism (PE) occurring during pulse-spray pharmacomechanical thrombolysis (PSPMT) of clotted hemodialysis grafts with use of either urokinase (UK) or heparinized saline (HS). Postintervention primary patency and complication rates were compared for each method of thrombolysis.

METHODS AND MATERIALS

Twenty-seven patients were enrolled in this prospective, randomized, double-blind study evaluating PE with two PSPMT agents. The doses of heparin were similar between groups. The only variable was that one group of patients received UK and the other received HS. In two cases, the venous anastomosis could not be crossed. Eleven patients were treated with UK and 14 with HS. Nuclear medicine perfusion lung scans were performed before treatment and after graft declotting procedures. Lung perfusion was quantified to 10% of a pulmonary segment (0 = normal perfusion, 1 = segmental perfusion defect), with nine segments counted for each lung.

RESULTS

Baseline nuclear medicine perfusion lung scan results were abnormal (> or = 20% segmental perfusion defect) in 19 patients (70.4%). New PE (one or more pulmonary segments) occurred in two patients treated with UK (18.2%) and nine patients treated with HS (64.3%; P = .04). All cases of PE were asymptomatic. Quantitative global pulmonary perfusion analyses revealed that treatment with UK improved flow to 0.2 +/- 2.0 pulmonary segments, whereas treatment with HS decreased perfusion to 1.0 +/- 1.7 segments (P = .16, NS). Although postintervention primary patency rates were similar according to life-table analysis (P = .76, NS), complication rates were higher with use of HS (n = 4, 28.6%) than with use of UK (n = 2, 18.2%) (P = .6, NS).

CONCLUSIONS

All PE were asymptomatic during PSPMT, but treatment with UK reduced the rate of PE and tended to result in smaller defects in lung scan results. Most patients undergoing hemodialysis have abnormal baseline perfusion scan results, but PSPMT with UK improved many of them. The postintervention primary patency rates were similar between groups, but complications were more frequent after treatment with HS.

Early rethrombosis of clotted hemodialysis grafts: graft salvage achieved with an aggressive approach

OBJECTIVE

The purpose of this study was to assess the efficacy of repeated pulsed spray pharmacomechanical thrombolysis for salvage of early rethrombosis of hemodialysis grafts and to identify factors that predict successful outcome.

MATERIALS AND METHODS

Thirty-four patients with initial successful thrombolysis were referred for repeated thrombolysis because of early rethrombosis. Repeated thrombolysis occurred within 1 month of initial thrombolysis. Technical success and patency rates were calculated. Causes of graft thrombosis and procedural modifications were analyzed.

RESULTS

The 39 rethrombosed grafts were successfully treated using pharmacomechanical thrombolysis, and patients underwent subsequent hemodialysis. The underlying flow-limiting stenoses were treated with balloon angioplasty using a larger balloon (41%), a same-size angioplasty balloon (18%), stent placement (15%), or increased anticoagulation (5%). A new stenosis location was discovered in 18%. Mean primary patency was 80.9 days (2.6 months) and secondary patency was 235.4 days (7.8 months). With life table analysis, 1-, 3-, 6-, and 12-month primary patency rates were 72%, 31%, 23%, and 15%, and secondary patency rates were 77%, 62%, 51%, and 31%, respectively. Graft patency rates in our study were compared with our institutional historic graft patency rates, with no significant difference noted (p = 0.76). No major procedural complications occurred.

CONCLUSION

Adequate technical success and patency rates for pharmacomechanical thrombolysis occur even for hemodialysis grafts that rethrombose within 1 month. After thrombolysis, aggressive search for and treatment of additional stenoses are warranted.

Adjunctive 3D US for achieving portal vein access during transjugular intrahepatic portosystemic shunt procedures

PURPOSE

To evaluate the usefulness of information provided by three-dimensional ultrasound (3D US) and to determine whether 3D US decreased the number of passes required to obtain portal vein (PV) access during creation of transjugular intrahepatic portosystemic shunts (TIPS).

MATERIALS AND METHODS

Intermittent 3D US volume acquisitions were obtained during creation of TIPS in 20 patients. Useful information provided by 3D US was tabulated. The number of passes required to achieve PV access was recorded and results were compared retrospectively to 25 patients who underwent TIPS without 3D US.

RESULTS

3D US documented that the operator's opinion of which hepatic vein had been selected was incorrect in nine patients (45%), detected unfavorable PV anatomy that required modification of equipment or technique in seven patients (35%), permitted estimation of the trajectory required to access the targeted PV in all patients (100%), assisted in selecting the optimal point along the hepatic vein for origination of the needle pass in 11 patients (55%), allowed avoidance of a large hepatocellular carcinoma in one patient (5%), and confirmed that access into the main PV was intrahepatic in four patients (20%). The mean number of needle passes decreased from 10.4 in the historic control group to 4.6 in the 3D US group (P = .0001).

CONCLUSION

3D US provided imaging information that detected technical errors and altered anatomy, and provided positional and directional information to significantly improve needle pass efficiency.

Adjunctive 3D US for achieving portal vein access during transjugular intrahepatic portosystemic shunt procedures

PURPOSE

To evaluate the usefulness of information provided by three-dimensional ultrasound (3D US) and to determine whether 3D US decreased the number of passes required to obtain portal vein (PV) access during creation of transjugular intrahepatic portosystemic shunts (TIPS).

MATERIALS AND METHODS

Intermittent 3D US volume acquisitions were obtained during creation of TIPS in 20 patients. Useful information provided by 3D US was tabulated. The number of passes required to achieve PV access was recorded and results were compared retrospectively to 25 patients who underwent TIPS without 3D US.

RESULTS

3D US documented that the operator's opinion of which hepatic vein had been selected was incorrect in nine patients (45%), detected unfavorable PV anatomy that required modification of equipment or technique in seven patients (35%), permitted estimation of the trajectory required to access the targeted PV in all patients (100%), assisted in selecting the optimal point along the hepatic vein for origination of the needle pass in 11 patients (55%), allowed avoidance of a large hepatocellular carcinoma in one patient (5%), and confirmed that access into the main PV was intrahepatic in four patients (20%). The mean number of needle passes decreased from 10.4 in the historic control group to 4.6 in the 3D US group (P = .0001).

CONCLUSION

3D US provided imaging information that detected technical errors and altered anatomy, and provided positional and directional information to significantly improve needle pass efficiency.

The effect of dopamine depletion from the caudate nucleus of the common marmoset (Callithrix jacchus) on tests of prefrontal cognitive function

This study examined the effects of depletion of dopamine from the caudate nucleus of the common marmoset (Callithrix jacchus), on tasks sensitive to prefrontal damage (attentional set-shifting and spatial delayed response). There was a marked impairment in performance on the spatial delayed response task, but performance on the attentional set-shifting task was relatively preserved except for an impairment in re-engagement of a previously relevant perceptual dimension. This pattern of impairment is distinct from that seen after excitotoxic lesions of the prefrontal cortex and in patients with Parkinson's disease. Though it is not possible to identify specific cognitive functions that are independent of dopaminergic modulation of the caudate nucleus, due to the partial nature of the lesion, the results do provide insight into those cognitive processes that appear most dependent on caudate dopamine.

Inhibitory control and affective processing in the prefrontal cortex: neuropsychological studies in the common marmoset

The orbitofrontal cortex has been ascribed a role in the inhibitory control, as well as in the emotional control, of behaviour. While damage to the orbitofrontal cortex in humans and non-human primates can cause inflexibility, impulsiveness and emotional disturbance, the relationship between these effects are unclear. Excitotoxic lesion studies in marmosets comparing the effects of cell loss within specific regions of the prefrontal cortex on performance of a range of behavioural tests reveal that mechanisms of response inhibition are not unique to the orbitofrontal cortex. Instead they are present in distinct cognitive domains for lowerorder as well as higher-order processing throughout the prefrontal cortex. Thus, the lateral prefrontal cortex is involved in the selection and control of action based upon higher-order rules while the orbitofrontal and medial prefrontal cortex may be involved in different but complementary forms of lower-order rule learning, their roles dissociable, as a result of their differential contribution to different types of associative learning.

The effect of dopamine depletion from the caudate nucleus of the common marmoset (Callithrix jacchus) on tests of prefrontal cognitive function

This study examined the effects of depletion of dopamine from the caudate nucleus of the common marmoset (Callithrix jacchus), on tasks sensitive to prefrontal damage (attentional set-shifting and spatial delayed response). There was a marked impairment in performance on the spatial delayed response task, but performance on the attentional set-shifting task was relatively preserved except for an impairment in re-engagement of a previously relevant perceptual dimension. This pattern of impairment is distinct from that seen after excitotoxic lesions of the prefrontal cortex and in patients with Parkinson's disease. Though it is not possible to identify specific cognitive functions that are independent of dopaminergic modulation of the caudate nucleus, due to the partial nature of the lesion, the results do provide insight into those cognitive processes that appear most dependent on caudate dopamine.

Preliminary experience with twenty perineal repairs using Indermil tissue adhesive

OBJECTIVE

To assess the use of Indermil tissue adhesive for perineal repair.

SETTING

Leeds General Infirmary, a teaching hospital with 4500 deliveries annually.

METHOD

Over a period of five months, 20 women who sustained either a second degree tear or who had an episiotomy at vaginal delivery had their perineal skin repaired with Indermil tissue adhesive. They were followed up prior to discharge and then by telephone once discharged.

RESULTS

Ten repairs followed normal vaginal deliveries, six were after ventouse deliveries, three after midcavity forceps delivery and one after a rotational forceps delivery. Three women noticed a burning sensation during application of adhesive. At follow up, 13 women were completely without problems, two complained of a sharp sensation from excess adhesive, one had silver nitrate applied at the six week check, two had small defects in the skin which healed well and in two women the skin edges broke down completely but did not need resuturing.

CONCLUSION

Indermil tissue adhesive appears to be a safe and effective method of skin closure for episiotomies and second degree tears. The skin closure is quick and painless.

Sign tracking in cuttlefish (Sepia officinalis)

Two groups of cuttlefish (Sepia officinalis) were used to demonstrate classical conditioning in this species and to determine whether the resulting approach response would be that of sign tracking or goal tracking. For cuttlefish in the paired condition, a flashing light was presented at one end of a long tank followed by food dropped into the center of the tank. For cuttlefish in the unpaired condition, food was dropped into the center of the tank either before or after the flashing-light stimulus. Paired cuttlefish oriented to the light, positioned themselves within striking distance, and occasionally attacked the light. Unpaired cuttlefish showed no reliable response to either stimulus. The results demonstrate that cuttlefish are capable of signal learning and that, under the conditions tested, cuttlefish sign tracked. This study begins a comparative analysis of learning in cuttlefish and offers a possible ecological advantage for sign-tracking behavior.

Performance norms for a rhesus monkey neuropsychological testing battery: acquisition and long-term performance

A computerized behavioral battery based upon human neuropsychological tests (CANTAB, CeNeS, Cambridge, UK) has been developed to assess cognitive behaviors of rhesus monkeys. Monkeys reliably performed multiple tasks, providing long-term assessment of changes in a number of behaviors for a given animal. The overall goal of the test battery is to characterize changes in cognitive behaviors following central nervous system (CNS) manipulations. The battery addresses memory (delayed non-matching to sample, DNMS; spatial working memory, using a self-ordered spatial search task, SOSS), attention (intra-/extra-dimensional shift, ID/ED), motivation (progressive-ratio, PR), reaction time (RT) and motor coordination (bimanual task). As with human neuropsychological batteries, different tasks are thought to involve different neural substrates, and therefore performance profiles should assess function in particular brain regions. Monkeys were tested in transport cages, and responding on a touch sensitive computer monitor was maintained by food reinforcement. Parametric manipulations of several tasks demonstrated the sensitivity of performance to increases in task difficulty. Furthermore, the factors influencing difficulty for rhesus monkeys were the same as those shown to affect human performance. Data from this study represent performance of a population of healthy normal monkeys that will be used for comparison in subsequent studies of performance following CNS manipulations such as infection with simian immunodeficiency virus (NeuroAIDS) or drug administration.

Importance of Doppler analysis of transmitted atrial waveforms prior to placement of central venous access catheters

PURPOSE

To assess the sensitivity of Doppler flow analysis of the axillary and internal jugular veins to screen for clinically occult thoracic central veno-occlusive disease and predict successful placement of central access catheters.

MATERIALS AND METHODS

Sixty-seven patients underwent both duplex sonographic evaluation of the axillary and internal jugular veins and contrast venography prior to placement of a central venous catheter. Duplex evaluation included visual evidence of veno-occlusive disease as well as the presence or absence of normal transmitted polyphasic atrial waves and respiratory variation of flow. Diagnostically adequate venograms were available for comparison with the duplex sonograms in 168 access routes (access site plus downstream conduit veins). The contrast venograms and sonograms were compared by using retrospective blinded interpretation. Outcome of attempted catheter placement was tabulated.

RESULTS

Directed sonographic imaging of the axillary and internal jugular vein allowed detection of access route veno-occlusive disease with a sensitivity of only 33.3%. Alternatively, when Doppler flow analysis found atrial waveforms that were not polyphasic, central conduit occlusive disease was detected with a sensitivity of 79.6%. Monophasic atrial waveforms were associated with a 25% failure rate of catheterization due to central vein occlusive disease, whereas polyphasic atrial waveforms were correlated with a 100% success rate for catheter placement.

CONCLUSION

In asymptomatic patients, sonographic imaging alone misses most instances of central veno-occlusive disease. However, Doppler flow analysis of transmitted atrial waveforms substantially improved the sensitivity. A normal polyphasic atrial waveform virtually excludes the possibility of a more central venous occlusion or stenosis greater than 80% and ensures an adequate route for central venous catheterization.

Poor relationship between arterial [lactate] and leg net release during exercise at 4,300 m altitude

We evaluated the hypotheses that on acute exposure to hypobaric hypoxia, sympathetic stimulation leads to augmented muscle lactate production and circulating [lactate] through a beta-adrenergic mechanism and that beta-adrenergic adaptation to chronic hypoxia is responsible for the blunted exercise lactate response after acclimatization to altitude. Five control and 6 beta-blocked men were studied during rest and exercise at sea level (SL), on acute exposure to 4,300 m (A1), and after a 3-wk sojourn at altitude (A2). Exercise was by leg cycling at 49% of SL peak O2 consumption (VO2 peak) (65% of altitude VO2 peak or 87 +/- 2.6 W); beta-blockade was by propranolol (80 mg 3x daily), femoral arterial and venous blood was sampled; leg blood flow (Q) was measured by thermodilution, leg lactate net release [ = (2) (1-leg Q) venous-arterial concentrationL] was calculated, and vastus lateralis needle biopsies were obtained. Muscle [lactate] increased with exercise and acute altitude exposure but regressed to SL values with acclimatization; beta-blockade had no effect on muscle [lactate]. Arterial [lactate] rose during exercise at SL (0.9 +/- 0.1 to 1.5 +/- 0.3 mM); exercise at A1 produced the greatest arterial [lactate] (4.4 +/- 0.8 mM), and exercise at A2 an intermediate response (2.1 +/- 0.6 mM). beta-Blockade reduced circulating [lactate] approximately 45% during exercise under all altitude conditions. increased transiently at exercise onset but then declined over time under all conditions. Blood and muscle "lactate paradoxes" occurred independent of beta-adrenergic influences, and the hypotheses relating the blood lactate response at altitude to beta-adrenergic mechanisms are rejected. During exercise at altitude, arterial [lactate] is determined by factors in addition to hypoxemia, circulating epinephrine, and net lactate release from active muscle beds.

The tissue adhesive indermil and its use in surgery

Indermil, in relation to the tissue adhesives described remains the state of the art with regard to function and clinical outcome. The advantage of an inventory sterile tissue adhesive that is to say one that is in the clinic or operating theatre ready for immediate use on demand is the requirement of modern surgical practice. Cost factors are also an important consideration in today's environment. A research study by the Department of Health Economics at the University of York found the cost of the Indermil tissue adhesive system equivalent to absorbable sutures and produced projected savings per patient in relation to conventional sutures with respect to theatre time and return patients' visits (6). In parallel a survey of patients showed 90% would prefer wound closure by an adhesive in relation to traditional sutures. There are few areas of surgical practice which cannot find some application for tissue adhesives. The growing international interest in adhesives and their application would confirm their importance and potential in surgery.

Perseveration and strategy in a novel spatial self-ordered sequencing task for nonhuman primates: effects of excitotoxic lesions and dopamine depletions of the prefrontal cortex

Damage to the prefrontal cortex disrupts the performance of self-ordered sequencing tasks, although the precise mechanisms by which this effect occurs is unclear. Active working memory, inhibitory control, and the ability to generate and perform a sequence of responses are all putative cognitive abilities that may be responsible for the impaired performance that results from disruption of prefrontal processing. In addition, the neurochemical substrates underlying prefrontal cognitive function are not well understood, although active working memory appears to depend upon an intact mesocortical dopamine system. The present experiments were therefore designed to evaluate explicitly the contribution of each of these abilities to successful performance of a novel spatial self-ordered sequencing task and to examine the contribution of the prefrontal cortex and its dopamine innervation to each ability in turn. Excitotoxic lesions of the prefrontal cortex of the common marmoset profoundly impaired the performance of the self-ordered sequencing task and induced robust perseverative responding. Task manipulations that precluded perseveration ameliorated the effect of this lesion and revealed that the ability to generate and perform sequences of responses was unaffected by excitotoxic damage to prefrontal cortex. In contrast, large dopamine and noradrenaline depletions within the same areas of prefrontal cortex had no effect on any aspect of the self-ordered task but did impair the acquisition of an active working memory task, spatial delayed response, to the same degree as the excitotoxic lesion. These results demonstrate that a lesion of the ascending monoamine projections to the prefrontal cortex is not always synonymous with a lesion of the prefrontal cortex itself and thereby challenge existing concepts concerning the neuromodulation of prefrontal cognitive function.

Dissociable forms of inhibitory control within prefrontal cortex with an analog of the Wisconsin Card Sort Test: restriction to novel situations and independence from "on-line" processing

Attentional set-shifting and discrimination reversal are sensitive to prefrontal damage in the marmoset in a manner qualitatively similar to that seen in man and Old World monkeys, respectively (Dias et al., 1996b). Preliminary findings have demonstrated that although lateral but not orbital prefrontal cortex is the critical locus in shifting an attentional set between perceptual dimensions, orbital but not lateral prefrontal cortex is the critical locus in reversing a stimulus-reward association within a particular perceptual dimension (Dias et al., 1996a). The present study presents this analysis in full and extends the results in three main ways by demonstrating that (1) mechanisms of inhibitory control and "on-line" processing are independent within the prefrontal cortex, (2) impairments in inhibitory control induced by prefrontal damage are restricted to novel situations, and (3) those prefrontal areas involved in the suppression of previously established response sets are not involved in the acquisition of such response sets. These findings suggest that inhibitory control is a general process that operates across functionally distinct regions within the prefrontal cortex. Although damage to lateral prefrontal cortex causes a loss of inhibitory control in attentional selection, damage to orbitofrontal cortex causes a loss of inhibitory control in affective processing. These findings provide an explanation for the apparent discrepancy between human and nonhuman primate studies in which disinhibition as measured on the Wisconsin Card Sort Test is associated with dorsolateral prefrontal damage, whereas disinhibition as measured on discrimination reversal is associated with orbitofrontal damage.

n-Butyl cyanoacrylate adhesive for skin closure of abdominal wounds: preliminary results

Tissue adhesives offer significant potential advantages over traditional methods of wound closure. A new n-butyl 2-cyanoacrylate adhesive formulation was utilised for the closure of abdominal wounds after general and laparoscopic gastrointestinal surgery. One hundred and two patients with 240 wounds were recruited. Wounds were classified as > 10 cm, n = 39; 5-9 cm, n = 27; and < 5 cm, n = 176. Complications included one small seroma and two partial superficial dehiscences. There were no incidences of wound infection. This preliminary study indicates that this tissue adhesive can safely and effectively be utilised for general abdominal wound closure. It should now be subjected to the rigorous of a randomised controlled trial to compare its performance against the more traditional methods of wound closure.

IVC filter tilt and asymmetry: comparison of the over-the-wire stainless-steel and titanium Greenfield IVC filters

PURPOSE

A comparison of tilting, caval coverage, asymmetry, and insertion problems with the over-the-wire stainless-steel and titanium versions of the Greenfield filter.

MATERIALS AND METHODS

The study compared 104 stainless-steel and 141 titanium Greenfield inferior vena cava (IVC) filter insertions. The angle the sheath and deployed filter made relative to the cava, as well as filter strut distribution, were determined from spot films. The proportionate caval coverage was computed from the cavogram (anteroposterior projection). Mean filter tilts, subgrouped by insertion site, and caval coverage were compared with the Student t test, whereas strut patterns were analyzed with a contingency table.

RESULTS

The filter caval and sheath caval angles correlated. The filter caval angles varied with insertion site, but were lowest with a right jugular approach. Caval coverage was identical with both designs. The stainless-steel version resulted in a more uniform distribution of struts in comparison with the titanium version. The incidence of insertion problems was not significantly different between the filter types.

CONCLUSIONS

While IVC filter tilting was not improved with the newer design, the pattern of struts was more uniformly symmetric with the stainless-steel device. The right jugular insertion site was associated with the lowest filter caval angles and the most symmetric pattern of struts.

Contrasting effects of excitotoxic lesions of the prefrontal cortex on the behavioural response to D-amphetamine and presynaptic and postsynaptic measures of striatal dopamine function in monkeys

The effects of excitotoxic lesions of the prefrontal cortex on behavioural, neurochemical and molecular indices of dopamine function in the caudate nucleus were studied in the marmoset. The lesion, which encompassed both the lateral and orbital regions of prefrontal cortex, made the animals more sensitive to the performance disrupting effects of the dopamine releasing drug, D-amphetamine, in a variation of the object retrieval task. Specifically, following drug administration, the lesioned marmosets were less able to gain access to food reward in the minimum number of responses. Analysis of the nature of the errors suggested that the deficit was not due to inhibition of a prepotent response as the lesioned monkeys were just as likely to make a detour reach to the unopened side of the box as a direct "line-of-sight" reach into the unopened front of the box. Rather, the data indicated a general disorganization of behaviour. The enhanced behavioural responsiveness to manipulations increasing presynaptic dopamine function was accompanied by neurochemical changes indicating a reduced responsiveness, as revealed by in vivo microdialysis. Thus, in lesioned animals, whilst there were no effects on baseline levels of extracellular dopamine in dorsolateral caudate, evoked release, both to systemic D-amphetamine and to a local depolarizing pulse of potassium ions, was attenuated. These opposite effects of the prefrontal cortex lesion on behavioural and neurochemical indices of striatal dopamine function occurred in the absence of any changes in striatal dopamine receptors of the D1 and D2 subtype, as determined both by radioligand binding assays and measurements of messenger RNA using in situ hydridization techniques. These data provide further insight into the interactions between prefrontal cortex and striatal dopamine function in the non-human primate. In particular, when taken in the light of our previous studies they indicate that following prefrontal manipulations, concurrence between behavioural and neurochemical indices of striatal dopamine function depends, critically, on the behavioural task. These findings are discussed with respect to the growing body of evidence implicating abnormalities in frontostriatal neurotransmission in complex disorders such as schizophrenia.

The use of Indermil (n-butyl cyanoacrylate) in otorhinolaryngology and head and neck surgery. A preliminary report on the first 33 patients

The authors present their initial experience of a new sterile medical grade cyanoacrylate adhesive (Indermil) in otolaryngeal and head and neck surgery. Thirty-three patients who underwent a variety of head and neck operations consented to have their skin incisions closed using the adhesive and 10 of those also underwent repair of the tympanic membrane, either as part of tympanoplasty or mastoid surgery. The history of the use of this class of adhesive is presented with an explanation of the chemical properties of these compounds. Advantages of using cyanoacrylate adhesives and future possible applications in otolaryngology and head and neck surgery are discussed.

Primate analogue of the Wisconsin Card Sorting Test: effects of excitotoxic lesions of the prefrontal cortex in the marmoset

Using a primate analogue of the Wisconsin Card Sort Test, this study demonstrated, for the first time, that lesions of the prefrontal cortex in monkeys produce a qualitatively similar impairment in attentional set-shifting to that seen following prefrontal cortical damage in humans. Although damage to the prefrontal cortex did not disrupt the ability of marmosets, a New World monkey, to maintain an attentional set, it did disrupt their ability to shift an attentional set. It also impaired their performance on discrimination reversal, object retrieval, and spatial delayed response, consistent with the effects of prefrontal damage in Old World monkeys. Comparison of the cognitive processes underlying discrimination reversal, object retrieval, and attentional set-shifting reveals the various types of inhibitory control provided by the prefrontal cortex.

Decreased bladder compliance in patients with myelomeningocele treated with radiological observation

PURPOSE

Recently others advocated frequent radiological surveillance to detect upper urinary tract deterioration in children with neurogenic bladder secondary to spina bifida. We reviewed the consequences of such expectant management on bladder compliance and urinary continence.

MATERIALS AND METHODS

We retrospectively reviewed the records of 214 children presenting to our spina bifida clinic in a 13-year period. Follow-up is available for 95 girls and 86 boys. Imaging studies of the kidneys were repeated at 6 to 12-month intervals. Urodynamics were performed when upper urinary tracts deteriorated or in incontinent school age children.

RESULTS

On radiographic study there was evidence of upper urinary tract deterioration in 79 children, including hydronephrosis in 34, hydronephrosis and vesicoureteral reflux in 19, and reflux only in 26. Follow up studies performed after clean intermittent catheterization and pharmacological therapy were instituted revealed resolution or improvement of upper tract deterioration in 52 patients (69%), while bladder compliance improved in only 42%. Surgical intervention was required in 34 children, despite improvement of upper tract changes in many of these patients on follow up radiographic studies.

CONCLUSIONS

Although radiological surveillance of patients with myelomeningocele allows recognition of upper tract changes, the effects of elevated outlet resistance on bladder compliance are not as readily reversible as the initial radiographic findings. The incidence of enterocystoplasty exceeds that reported for patients treated prospectively based on urodynamic findings, which should be considered in the treatment of these children.

Does cervical spinal cord injury induce a higher incidence of complications after prophylactic Greenfield inferior vena cava filter usage?

PURPOSE

To determine whether acute cervical spine injury represents a risk factor for complications from prophylactic placement of current generation Greenfield inferior vena cava (IVC) filters.

MATERIALS AND METHODS

A retrospective chart review performed during a 7-year period identified 11 patients with acute cervical spinal cord injuries who underwent prophylactic Greenfield IVC filter insertion. Specific complications evaluated included symptomatic pulmonary embolism (PE), migration, filter base diameter changes, caval perforation, and thrombosis. The amount of migration and changes in filter base dimension were compared statistically with a control population of IVC filter patients (n = 16) without cervical spine injuries.

RESULTS

Filter migration (> 10 mm) was the most common complication (46%). Migration usually is caudally directed (64%), may occur early (36% moved > 10 mm within a 30-day period), and is often asymptomatic. The prevalence of filter migration greater than 30 mm was 27%. The average amount of migration for the subpopulation under study was greater than that seen with the control population (P < .05). No statistically significant change in filter base size occurred. The study population also had rates of PE (9%-18%), caval perforation (9%), and IVC thrombus formation (18%) that were higher than the rates in historical controls. The majority of patients with these complications received vigorous pulmonary toilet (46%), including "quad coughs" or cardiopulmonary resuscitation (18%).

CONCLUSIONS

Acute cervical spinal cord injury and the associated supportive care may be associated with an increased risk for caudal IVC filter migration, IVC perforation, caval thrombosis, and PE.

Primate analogue of the Wisconsin Card Sorting Test: effects of excitotoxic lesions of the prefrontal cortex in the marmoset

Using a primate analogue of the Wisconsin Card Sort Test, this study demonstrated, for the first time, that lesions of the prefrontal cortex in monkeys produce a qualitatively similar impairment in attentional set-shifting to that seen following prefrontal cortical damage in humans. Although damage to the prefrontal cortex did not disrupt the ability of marmosets, a New World monkey, to maintain an attentional set, it did disrupt their ability to shift an attentional set. It also impaired their performance on discrimination reversal, object retrieval, and spatial delayed response, consistent with the effects of prefrontal damage in Old World monkeys. Comparison of the cognitive processes underlying discrimination reversal, object retrieval, and attentional set-shifting reveals the various types of inhibitory control provided by the prefrontal cortex.

Acclimatization to 4,300-m altitude decreases reliance on fat as a substrate

We tested the hypothesis that exposure to altitude decreases reliance on free fatty acids (FFA) as substrates and increases dependency on blood glucose. Therefore, the effects of exercise, hypobaric hypoxia, and altitude acclimatization on FFA, glycerol and net glucose uptake and release [= 2(leg blood flow)(arteriovenous concentration)] and on fatty acid (FA) consumption by the legs (= 3 x glycerol release + FFA uptake) were measured. Because sympathetic responses have been implicated, we utilized nonspecific beta-blockade and observed responses to exercise, altitude, and altitude acclimatization. We studied six healthy beta-blocked men (beta) and five matched controls (C) during rest and cycle ergometry exercise (88 W) at 49% of sea-level (SL) peak O2 uptake at the same absolute power output on acute altitude exposure (A1; barometric pressure = 430 Torr) and after 3 wk of chronic altitude exposure to 4,300 m (A2). During exercise at SL, FA consumption rates increased (P < 0.05). On arrival at 4,300 m, resting leg FFA uptake and FA consumption rates were not significantly different from those at SL. However, after acclimatization to altitude, at rest leg FA consumption decreased to essentially zero in both C and beta groups. During exercise to altitude after acclimatization, leg FA consumption increased significantly, but values were less than at SL or A1 (P < 0.05), whereas glucose uptake increased relative to SL values. Furthermore, beta-blockade significantly increased glucose uptake relative to control. We conclude that 1) chronic altitude exposure decreases leg FA consumption during rest and exercise; 2) relative to SL FFA uptake decreases while glucose uptake increases during exercise at altitude; and 3) beta-blockade potentiates these effects.

Predicting treatment retention of women dependent on cocaine

The purpose of this research was (a) to assess differences in retention patterns and discharge status across three program settings; and (b) to examine selected pretreatment characteristics that might help predict treatment retention, which was operationalized as length of time in treatment. Three groups of pretreatment characteristics were examined. They included demographic factors, drug use and treatment history, and psychological status and symptomology. Clients in the intensive day treatment program tended to stay longer and were more likely to successfully complete the program than either clients in the outpatient or the traditional residential programs. In general, pretreatment client characteristics were not helpful in predicting length of time in treatment regardless of program type. Few pretreatment characteristics were related to retention within programs and significant predictors differed across treatment settings.

Detection and treatment of dysfunctional hemodialysis access grafts: effect of a surveillance program on graft patency and the incidence of thrombosis

PURPOSE

To determine the value of a hemodialysis graft surveillance program in reducing the incidence of graft thrombosis and prolonging graft patency by means of early detection and percutaneous transluminal angioplasty (PTA) of graft-related stenoses.

MATERIALS AND METHODS

For 4-1/2 years, routine graft examination and measurement of several dialysis parameters were used to identify 106 cases of suspected graft dysfunction in 57 patients (56 men, one woman; aged 27-76 years). Graft-related stenoses detected with angiography were treated with PTA.

RESULTS

Abnormal physical examination findings were the most common sole indication of graft dysfunction. Of the 106 cases referred for angiographic evaluation, 97 (92%) had at least one lesion. PTA was successful in 88 of 90 treated cases. The primary patency rates at 1 year were 16% for arteriovenous fistulas (AVFs) and 23% for polytetrafluoroethylene (PTFE) grafts. Early detection of stenoses by means of surveillance and repeated PTA enabled 1-year primary assisted patency rates of 67% for AVFs and 68% for PTFE grafts. The incidence of graft thrombosis fell from 48% in 1988 to 17% in 1994 (P < .001).

CONCLUSION

The hemodialysis graft surveillance program resulted in a statistically significant reduction in the incidence of graft thrombosis. Although primary patency rates after PTA were low, repeated PTA of detected stenoses allowed good primary assisted patency rates.

Comparison of cognitive function in human and non-human primates

Fundamental to any comparative study of cognitive function in monkey and man is the demonstration of behavioral homology, viz. that the same cognitive function is being studied in both species. This paper considers a variety of psychological issues that need to be taken into account when attempting to demonstrate behavioural homology. Examples are taken from studies of attentional set-shifting, discrimination reversal learning, spatial working memory and episodic memory. Whilst highlighting the pitfalls to be avoided in the future, these examples also demonstrate the enormous contribution that such studies have had to our understanding of the functions of the temporal lobes and frontal lobes. Moreover, they also illustrate the enormous potential in defining the cognitive functions and dysfunctions of the prefronto-striatal circuitry which underlie so many neurodegenerative and neuropsychiatric disorders.

Dissociation in prefrontal cortex of affective and attentional shifts

The prefrontal cortex is implicated in such human characteristics as volition, planning, abstract reasoning and affect. Frontal-lobe damage can cause disinhibition such that the behaviour of a subject is guided by previously acquired responses that are inappropriate to the current situation. Here we demonstrate that disinhibition, or a loss of inhibitory control, can be selective for particular cognitive functions and that different regions of the prefrontal cortex provide inhibitory control in different aspects of cognitive processing. Thus, whereas damage to the lateral prefrontal cortex (Brodmann's area 9) in monkeys causes a loss of inhibitory control in attentional selection, damage to the orbito-frontal cortex in monkeys causes a loss of inhibitory control in 'affective' processing, thereby impairing the ability to alter behaviour in response to fluctuations in the emotional significance of stimuli. These findings not only support the view that the prefrontal cortex has multiple functions, but also provide evidence for the distribution of different cognitive functions within specific regions of prefrontal cortex.

Altitude and beta-blockade augment glucose utilization during submaximal exercise

To test the hypothesis that altitude exposure increases glucose utilization and that this increment is mediated by a beta-adrenergic mechanism, the effects of hypobaric hypoxia and beta-blockade on glucose rates of appearance (Ra), disappearance (Rd), oxidation (Rox), and leg uptake [G = 2(arteriovenous glucose difference)(1 - leg blood flow)] were measured during rest and a given submaximal exercise task. We studied six healthy beta-blocked (beta) men [26.7 +/- 1.2 (SE) yr, 74.0 +/- 6.6 kg] and five matched controls (C; 26 +/- 1.2 yr, 69.3 +/- 2.6 kg) in energy and nitrogen balance during rest and leg cycle-ergometer exercise at sea level, on acute altitude exposure to 4,300 m (barometric pressure = 463 Torr), and after 3 wk of habituation. Subjects received a primed continuous infusion of [6,6-2H]- and [1-13C]glucose, rested for > or = 90 min, and then immediately exercised for 45 min at 89 W, which elicited 49% of sea-level peak O2 consumption (VO2peak; 65% of altitude VO2peak). At sea level, resting Ra was 1.47 +/- 0.19 and 1.66 +/- 0.16 mg x kg-1 x min-1 for C and beta, respectively, and increased to 3.04 +/- 0.25 and 3.56 +/- 0.27 mg x kg-1 x min-1, respectively, during exercise. Thus glucose Ra was significantly increased by beta-blockade during rest and exercise at sea level. At sea level, beta-blockade increased leg G, which accounted for 49 and 69% of glucose disposal during exercise in C and beta, respectively. On acute altitude exposure, glucose Ra rose significantly during rest and exercise relative to sea level, whereas blockade continued to augment this increment. During exercise on acute exposure, G increased more than at sea level and accounted for a greater percentage (80 and 97%, respectively) of Rd in C and beta during exercise. Similarly, Rox values, particularly during exercise, were increased significantly at altitude relative to sea level, and beta-blockade potentiated this effect. During a given submaximal exercise task after acclimatization, glucose Ra, Rox, and G were increased relative to sea level, but these increments were less than those in response to exercise measured on acute exposure. We conclude that altitude exposure increases glucose use during rest and a given submaximal exercise bout and beta-blockade exaggerates the response.

Hand ischemia in patients with hemodialysis access grafts: angiographic diagnosis and treatment

PURPOSE

To determine the cause of symptoms and efficacy of transcatheter therapy in a series of patients with dialysis grafts and hand pain referred for arteriography.

MATERIALS AND METHODS

Thirteen patients with 14 hemodialysis grafts underwent arteriography for possible hand ischemia. The sites of proximal graft anastomosis were the distal radial artery (n = 6) and the mid- to distal brachial artery (n = 6). Transcatheter therapy was performed via the graft or by antegrade brachical puncture.

RESULTS

The cause of symptoms was ischemia from obstructive arterial disease in seven cases (three with superimposed steal), graft steal alone in three, ischemic monomelic neuropathy in two, and carpal tunnel syndrome in two. Five arterial stenoses were treated with angioplasty, with improvement or resolution of symptoms in four patients.

CONCLUSION

In this group, symptoms were usually the result of inflow or outflow arterial disease, alone or in combination with graft steal. Transcatheter therapy (angioplasty or embolization) is effective in selected cases.

Pulse-spray pharmacomechanical thrombolysis of thrombosed hemodialysis access grafts: long-term experience and comparison of original and current techniques

OBJECTIVE

Pulse-spray pharmacomechanical thrombolysis is an evolving method for the treatment of vascular occlusions in which a highly concentrated fibrinolytic agent is injected as a high-pressure spray directly into thrombus. The purpose of this retrospective study was to analyze our long-term experience with this technique for the treatment of clotted hemodialysis grafts and to compare the efficacy and safety of the original and current methods.

SUBJECTS AND METHODS

Over 6 years, 284 cases of dialysis graft thrombosis were considered suitable for treatment with pulse-spray thrombolysis. The original technique involved the injection of highly concentrated urokinase directly into a clot through two crisscross catheters with multiple side holes. The current technique includes early fragmentation of residual clot with a balloon catheter, intrathrombic injection of heparin, mechanical treatment of a lysis-resistant clot at the arterial anastomosis, and routine administration of aspirin. After thrombolysis, underlying obstructions were treated with balloon angioplasty, atherectomy, or stents. The technical success, immediate clinical success, and frequency of complications for the entire population were analyzed. In addition, the results for 36 cases treated with the original technique were compared with the results for 37 recent cases treated with the current technique.

RESULTS

Of 284 cases considered suitable for treatment, thrombolysis was not done in eight cases because the venous anastomosis could not be crossed. Thrombolysis was discontinued in two cases because of extravasation of contrast material. The technical success for all grafts considered for treatment was 96%; 92% of treated grafts remained patent for at least 24 hr. Major complications occurred in 1% of cases, and minor complications occurred in 9% of cases. The clinical efficacies of the original and current techniques were 86% and 92%, respectively. The mean thrombolytic agent infusion time was reduced from 44 +/- 20 min to 23 +/- 13 min (p < .001). The overall procedure time for the recently treated subgroup was 67 +/- 26 min. There was no significant difference in the frequencies of major and minor complications between the treatment subgroups.

CONCLUSION

Pulse-spray pharmacomechanical thrombolysis is a reliable, rapid, and safe method for recanalization of occluded dialysis grafts. The current technique has been proven as safe and effective as the original technique but offers the advantage of a significant reduction in the time required for the infusion of thrombolytic agent.

Postangiographic femoral artery pseudoaneurysms: further experience with US-guided compression repair

PURPOSE

To assess the efficacy of ultrasound-guided compression repair (UGCR) in postcatheterization femoral artery pseudoaneurysms.

MATERIALS AND METHODS

One hundred thirty-three patients with pseudoaneurysms were considered for UGCR. Patients underwent compression with duplex and color Doppler ultrasound. Immediate and long-term successes were evaluated.

RESULTS

Seven patients were not candidates for UGCR. UGCR was technically possible in 117 of the 126 patients who were candidates. UGCR was successful in 109 patients. The failure rate was significantly higher in patients who were receiving anticoagulant medication (P < .001). Pseudoaneurysm size, age, and structure (simple vs multiloculated) had no bearing on success or failure. The time required for successful compression was not related to treatment with anticoagulants but was related to pseudoaneurysm structure. Complications included one case of a distal embolus and two episodes of hypotension.

CONCLUSION

UGCR is a simple and expedient method for the treatment of postcatheterization femoral artery pseudoaneurysms.

Prolonging the life of difficult hemodialysis access using thrombolysis, angiography, and angioplasty

Prolonging the life of vascular access sites is one of the most pressing problems facing the nephrology team in the ongoing care of chronic hemodialysis patients. Thus, the ability to salvage a failing vascular access is important in any circumstance, but salvage is particularly critical in medically complicated situations. The following case presents just such a situation, one in which available access sites were limited and in which salvaging the function of a local access site obviated the need for major surgical intervention for more than 4 years. This example shows the efficacy of nonsurgical thrombolysis and the place of vascular radiology in the long-term preservation of access patency and follow-up care.

Is thrombolysis of occluded popliteal and tibial bypass grafts worthwhile?

PURPOSE

We analyzed the short- and long-term results for patients undergoing thrombolysis of occluded infrainguinal bypass grafts at our institution over a 62-month period.

METHODS

Thirty-one patients with 40 episodes of graft thrombosis in 33 grafts managed by thrombolysis were retrospectively reviewed. The effects of graft age, material, and anatomy, symptoms, treatment, anticoagulation, and occlusion duration were evaluated for impact on patency after thrombolysis. Dose and duration of therapy with use of the technique of pulse-spray thrombolysis was assessed.

RESULTS

Thrombolysis successfully reestablished patency in 92% of grafts treated. Mean lysis time and urokinase dose were 118 minutes and 607,000 units, respectively. Responsible lesions were identified and treated by angioplasty or surgery in 35 of 37 cases. The patency rate after thrombolysis was 28% at 30 months, and the secondary patency rate was 46% at 18 months. Duration of occlusion, symptoms, treatment, graft anatomy, and prior graft revision did not impact on patency. Mean secondary patency was 21.5 months in grafts in place over 1 year and 7.0 months in grafts in place for less than 1 year. Mean secondary patency was 23.8 months in polytetrafluoroethylene grafts and 8.4 months in vein grafts. The limb salvage rate was 84% at 30 months, and the patient survival rate was 84% at 42 months.

CONCLUSIONS

Pulse-spray thrombolysis is effective in rapidly recanalizing thrombosed infrainguinal grafts. Grafts failing in the first year after placement should generally be replaced, reserving thrombolysis and revision for grafts greater than 1 year old. Vein grafts tolerate thrombosis less well than synthetic conduits and have decreased long-term patency.