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A persistent neurological deficit, such as paraplegia or paraparesis, secondary to spinal cord injury remains one of the most feared complications of surgery on the descending thoracic or abdominal aorta. This is despite sophisticated advances in imaging and the use of less invasive endovascular procedures. Extensive fenestrated endovascular aortic graft prostheses still carry a risk of spinal cord injury of up to 10%; thus, this risk should be identified and strategies implemented to protect the spinal cord and maintain perfusion. The patients at highest risk are those undergoing extensive thoracic aortic stenting including thoracic, abdominal, and pelvic vessels. Although many techniques are available, lumbar cerebrospinal fluid drainage remains the most frequent intervention, along with maintenance of perfusion pressure and possibly staged procedures to allow collateral vessel stabilization. Many questions remain regarding other technical aspects, spinal cord monitoring and cooling, pharmacological protection, and the optimal duration of interventions into the postoperative period., (© The Author 2016. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Despite the intensity of the search for genes causing inherited retinal degenerations over the past 3 decades, of the approximately 200 disease genes identified to date, all appear to be ordinary housekeeping genes specifying proteins playing basic structural and functional roles in the mature photoreceptor cells. No genes or genetic elements have been identified which can be construed as having a specific morphogenic role, directing the development of the cytoarchitecture of any particular retinal cell. The evidence suggests that the cytoarchitecture of the retinal photoreceptors, although enormously complex, arises from the self-organization of the cells constituents without any regulation or direction from an external genetic blueprint.

Background: The iliac bifurcation device (William A Cook Australia, Brisbane, QLD, Australia) is a new endovascular device for iliac aneurysm repair. We review the indications for use, device characteristics, deployment options and the results of our case series., Methods: The most common indication for deployment is endovascular aortic aneurysm repair (EVAR) with common iliac aneurysm repair. The standard deployment sequence can be adapted to increase the utility of the device. Data were collected prospectively. Follow-up was performed with plain X-ray, ultrasound and computed tomography (CT) scan., Results: Between 2004 and 2007, 25 patients had their common iliac artery aneurysm repaired using the iliac bifurcation device. There were 23 male and 2 female patients. Median age was 75 years (range 60-85). The median follow-up was 12 months (range 1-38). Twenty-one procedures were combined with EVAR. The median abdominal aortic aneurysm diameter was 60 mm (range 31-97), and the median common iliac artery aneurysm diameter was 37 mm (range 24-71). Technical success was achieved in 100% of cases. There were no acute branch vessel occlusions. There was one early type I endoleak (4%). There was one death (4%) in the 30-day period post-procedure. There was one late type I endoleak (4%)., Conclusions: The iliac bifurcation device achieves endovascular common iliac artery aneurysm repair with preservation of internal iliac artery flow. There are multiple different applications of the device and complementary deployment techniques. High rates of technical success and low rates of branch vessel occlusion are possible.

Background: To maximize the benefit of carotid endarterectomy (CEA) in stroke prevention its complication rate must be minimized. The purpose of this study was to report the outcomes of a large series of CEA carried out under regional anaesthesia with selective shunting, with particular emphasis on identifying predictors for perioperative stroke and mortality., Methods: Between 1987 and 2003 the data for 1665 consecutive regional anaesthetic CEA carried out in 1495 patients were collected prospectively; awake neurological testing facilitated selective shunting. Preoperative data, intraoperative events and postoperative in-hospital complications were recorded and analysed., Results: There were 38 non-fatal strokes (2.3%) and 10 deaths (0.6%), giving a combined stroke and mortality rate of 2.9%. Only patients who needed shunting were found to have significantly higher rate of postoperative stroke and mortality (7.0 vs 1.9%, P < 0.001). Patient characteristics, comorbidities, indication for operation (P = 0.34) and the degree of stenosis of the contralateral carotid artery (P = 0.65) were not found to be predictive of perioperative stroke or mortality, although the latter two were found to be predictive of the need for shunting (P < 0.001 and P = 0.002)., Conclusion: Regional anaesthetic CEA is a safe and effective technique with excellent morbidity and mortality rates. The technique can be undertaken safely regardless of the indication for endarterectomy or the status of the contralateral carotid artery. Patients who developed intraoperative neurological changes requiring shunting are identified as high risk for perioperative stroke or mortality and should therefore be carefully monitored postoperatively.

Before Darwin many biologists considered organic forms to be immutable natural forms or types which like inorganic forms such as atoms or crystals are part of a changeless world order and determined by physical law. Adaptations were viewed as secondary modifications of these 'crystal like' abstract afunctional 'givens of physics.' We argue here that much of the emerging picture of biological order in the subcellular realm resembles closely the pre-Darwinian conception of nature. We point out that in the subcellular realm, between nano and micrometers, physical law necessarily plays a far more significant role in organizing matter than in the familiar 'Darwinian world' between millimeters and meters (where matter can be arranged into almost any contingent artifactual arrangement we choose, as witness Lego toys, watches or jumbo jets). Consequently, when deploying matter into complex structures in the subcellular realm the cell must necessarily make extensive use of natural forms-such as the protein and RNA folds, microtubular forms and tensegrity structures-which like atoms or crystals self-organize under the direction of physical law into what are essentially 'pre-Darwinian' afunctional abstract molecular architectures in which adaptations are trivial secondary modifications of what are evidently primary givens of physics.

Before the Darwinian revolution many biologists considered organic forms to be determined by natural law like atoms or crystals and therefore necessary, intrinsic and immutable features of the world order, which will occur throughout the cosmos wherever there is life. The search for the natural determinants of organic form-the celebrated "Laws of Form"-was seen as one of the major tasks of biology. After Darwin, this Platonic conception of form was abandoned and natural selection, not natural law, was increasingly seen to be the main, if not the exclusive, determinant of organic form. However, in the case of one class of very important organic forms-the basic protein folds-advances in protein chemistry since the early 1970s have revealed that they represent a finite set of natural forms, determined by a number of generative constructional rules, like those which govern the formation of atoms or crystals, in which functional adaptations are clearly secondary modifications of primary "givens of physics." The folds are evidently determined by natural law, not natural selection, and are "lawful forms" in the Platonic and pre-Darwinian sense of the word, which are bound to occur everywhere in the universe where the same 20 amino acids are used for their construction. We argue that this is a major discovery which has many important implications regarding the origin of proteins, the origin of life and the fundamental nature of organic form. We speculate that it is unlikely that the folds will prove to be the only case in nature where a set of complex organic forms is determined by natural law, and suggest that natural law may have played a far greater role in the origin and evolution of life than is currently assumed.

Purpose: To report a new phenotype in retinitis pigmentosa (RP) patients with CRB1 mutations at the RP12 locus., Patients: Thirty-seven patients from two Pakistani families with severe retinitis pigmentosa., Methods: Samples were screened with single-strand conformation polymorphism analysis followed by DNA sequencing of the coding sequence of the CRB1 gene., Results: Two novel CRB1 mutations were discovered. No patients had evidence of preservation of the para-arteriolar retinal pigment epithelium (PPRPE) that has been previously reported in all cases of RP associated with CRB1 mutations., Conclusions: Patients with severe autosomal recessive (or simplex) RP who lack the finding of PPRPE should not be excluded from molecular analysis of CRB1 purely because they lack the clinical feature of PPRPE. This report illustrates that RP at the RP12 locus is not clinically uniform. The absence of PPRPE cannot be used to exclude CRB1 as a potential molecular explanation for RP.

The disks of vertebrate photoreceptors are produced by outgrowths of the plasma membrane. Hence genes that encode retinal proteins targeted to plasma membrane protrusions represent candidates for inherited retinal degenerations. One such candidate is the gene encoding human prominin (mouse)-like 1 (PROML1, previously known as AC133 antigen) which belongs to the prominin family of 5-transmembrane domain proteins. Murine prominin (prom) shows a strong preference for plasma membrane protrusions in a variety of epithelial cells whereas PROML1 is expressed in retinoblastoma cell lines and adult retina. In the present study, molecular genetic analyses of a pedigree segregating for autosomal recessive retinal degeneration indicated that the affected individuals were homozygous for a nucleotide 1878 deletion in PROML1. This alteration is predicted to result in a frameshift at codon 614 with premature termination of translation. Expression of a similar prom deletion mutant in CHO cells indicated that the truncated protein does not reach the cell surface. Immunocytochemistry revealed that prom is concentrated in the plasma membrane evaginations at the base of the outer segments of rod photoreceptors. These findings suggest that loss of prominin causes retinal degeneration, possibly because of impaired generation of the evaginations and/or impaired conversion of the evaginations to disks.

Retinitis pigmentosa (RP) is a group of clinically and genetically heterogeneous disorders characterised by night blindness, constriction of visual field, and dystrophic changes of the retina. Previous genetic studies have shown extensive allelic and non-allelic genetic heterogeneity of RP. Here we describe an Indian family with multiple consanguineous marriages and a total of four patients with autosomal recessive (AR) RP. The homozygosity mapping strategy was successfully used and indicated close linkage between the disease locus and D2S380, D2S441, D2S291, and D2S1394 with maximum lod scores between 1.51-3.07 at theta=0.00. The analysis of multiply informative meioses maps the locus (RP28) for ARRP in this family between D1S1337 and D2S286 on 2p11-p15. The involvement of visinin (VSNL1), a promising candidate gene assigned to chromosome 2p by previous studies, has been excluded by the absence of linkage.

Autosomal recessive retinitis pigmentosa (arRP) is a genetically and clinically heterogeneous and progressive degenerative disorder of the retina, leading usually to severe visual handicap in adulthood. To date, disease loci/genes have been mapped/identified only in a minority of cases. DNA samples were collected from 20 large consanguineous Indian families, in which arRP segregated and that were suitable for homozygosity mapping of the disease locus. After excluding linkage to all known arRP loci, a genome-wide scan was initiated. In two families, homozygosity mapping, haplotype analysis, and linkage data mapped the disease locus (RP22) in an approximately 16-cM region between D16S287 and D16S420 on the proximal short arm of chromosome 16. No mutation has been found by direct sequencing in the gene (CRYM) encoding micron crystallin, which maps in the critical region.

Autosomal recessive childhood-onset severe retinal dystrophy (arCSRD) designates a heterogeneous group of disorders affecting rod and cone photoreceptors simultaneously. The most severe cases are termed Leber congenital amaurosis (LCA), while the less aggressive forms are usually considered juvenile retinitis pigmentosa. Recently, mutations in the retinal-specific guanylate cyclase gene were found in patients with LCA. Disease genes implicated in other forms of arCSRD are expected to encode proteins present in the neuroretina or in the retinal pigment epithelium (RPE). The RPE, a monolayer of cells separating the vascular-rich choroid and the neuroretina, is in intimate contact with the outer segments of rods and cones via the microvilli surrounding the photoreceptors. The RPE expresses a tissue-specific and evolutionarily highly conserved 61 kD protein (RPE65) present at high levels in vivo. Although the function of RPE65 is not yet known, an important role in the RPE/photoreceptor vitamin-A cycle is suggested by the fact that RPE65 associates both with serum retinol-binding protein and with the RPE-specific 11-cis retinol dehydrogenase, an enzyme active in the synthesis of the visual pigment chromophore 11-cis retinal. Here we report that the analysis of RPE65 in a collection of about 100 unselected retinal-dystrophy patients of different ethnic origin revealed five that are likely to be pathogenic mutations, including a missense mutation (Pro363Thr), two point mutations affecting splicing (912 + 1G-->T and 65 + 5G-->A) and two small re-arrangements (ins144T and 831del8) on a total of nine alleles of five patients with arCSRD. In contrast to other genes whose defects have been implicated in degenerative retinopathies, RPE65 is the first disease gene in this group of inherited disorders that is expressed exclusively in the RPE, and may play a role in vitamin-A metabolism of the retina.

Inadequate levels of all-trans-retinol in the blood cause retinal dysfunction; hence, genes implicated in retinal vitamin-A metabolism represent candidates for inherited retinal degenerations. In the current study, molecular genetic analysis of a consanguineous pedigree segregating for non-syndromic autosomal recessive retinitis pigmentosa (arRP) indicated that the affected siblings were homozygous by descent for a G4763A nucleotide substitution in RLBP1, the gene encoding cellular retinaldehyde-binding protein (CRALBP). This substitution is predicted to replace an arginine with glutamine at residue 150. CRALBP is not expressed in photoreceptors but is abundant in the retinal pigment epithelium (RPE) and Müller cells of the neuroretina, where it carries 11-cis-retinol and 11-cis-retinaldehyde. When expressed in bacteria, recombinant CRALBP (rCRALBP) containing the R150Q substitution was less soluble than wild-type rCRALBP. Mutant rCRALBP was purified from the soluble cell lysate and the protein structure was verified by mass spectrometry. The mutant protein lacked the ability to bind 11-cis-retinaldehyde. These findings suggest that arRP in the current pedigree results from a lack of functional CRALBP, presumably leading to disruption of retinal vitamin-A metabolism.

Three surgeons performed 180 atherectomy procedures in 161 patients using the Transluminal Extraction Catheter in 144 and the Auth Rotablator in 36. The primary patency rate was 55% at 1 year and 46% at 2 years, and failure was caused by stenosis in 28 (15.6%) and occlusion in 61 (33.7%) limbs. Multivariate Cox regression analysis showed significantly better outcome if the indication was claudication, the lesion was short or there was associated stenting. Vascular laboratory surveillance was performed in 93 limbs in 83 patients. Cox regression analysis in this subgroup also showed a significant relationship between outcome and the maximum peak systolic velocity from a duplex scan at the last study performed. Receiver operating characteristics curves showed that a raised maximum peak systolic velocity best predicted late failure (sensitivity 84%, specificity 66% for > 200 cm/s; sensitivity 72%, specificity 84% for > 250 cm/s); the velocity ratio at the stenosis to that in the segment above or the resting ankle/brachial pressure index were less predictive. For 50 procedures studied in the vascular laboratory which remained successful to the end of the study, maximum peak systolic velocities were > 250 cm/s from the first postoperative study, suggesting residual stenosis in 6%, or increased to become > 250 cm/s by the last study, suggesting recurrent stenoses in 12%. For 43 procedures which were studied and later failed, velocities were > 250 cm/s from the first test in 26% or increased to > 250 cm/s by the last test before failure in 40%. Vascular laboratory surveillance helps to predict outcome after atherectomy. Failure may be a result of residual disease from the time of the procedure or from restenosis. The apparent high incidence of clinically manifest or developing stenoses raises doubts as to the benefit of atherectomy over balloon dilatation alone.

Endovascular surgery is the vascular equivalent of minimally invasive surgery. It offers the benefits of minimal morbidity and mortality rates as well as short hospital stay, with its associated cost curtailment. In spite of many technological innovations, only balloon dilatation and intravascular stenting have established their places in vascular surgery with the newer field of stent grafting for both occlusive and aneurysmal disease still being evaluated.

Oguchi disease is a rare autosomal recessive form of congenital stationary night blindness. The condition is associated with fundus discolouration and abnormally slow dark adaptation. Earlier studies suggested that the 48 kD protein S antigen may be involved in the recovery phase of light transduction. Previous cytogenetic and linkage studies have localised the S antigen gene (SAG) to chromosome 2q37.1. In the present study markers which map to distal chromosome 2q were typed in an inbred Oguchi pedigree. The segregation data obtained suggested that the affected subjects are homozygous by descent for a region between D2S172 and D2S345. An intragenic SAG polymorphism was homozygous in all affected people and a recombination event suggested that SAG maps proximal to D2S345. Collectively, these findings support the hypothesis that a defect in S antigen may be responsible for Oguchi disease.

A large Pakistani family with several consanguineous marriages is described, in which autosomal recessive retinitis pigmentosa is segregating. Linkage studies revealed close linkage between the disease locus and six loci on chromosome 1q (D1S158, F13B, D1S422, D1S412, D1S413, and D1S53) with maximum lod scores ranging from 0.988-4.657 at theta = 0.065-0.235. However, the analysis of individual nuclear families showed very close linkage without recombination in three branches and several recombinants and negative lod scores throughout in the fourth branch. These results strongly suggest that mutations of two different genes are responsible for the disease in the 'linked' and 'unlinked' branches. Parallel to the linkage heterogeneity, clear phenotypic differences have been observed among the 'linked' and 'unlinked' parts. Our findings demonstrate that in case of recessive disorders the possibility of non-allelic genetic heterogeneity should always be considered, even within the same kindred and in genetic isolates if a largely extended pedigree is analysed.

Purpose: To determine whether the Auth Rotablator device is suitable for endoluminal atherectomy for infrainguinal occlusive arterial disease., Methods: Two surgeons used the Auth Rotablator to perform 36 infrainguinal atherectomy procedures in 34 patients for severe intermittent claudication in 21, critical ischemia in 12, or graft stenosis in 3 limbs. There were 24 stenoses and 12 occlusions. Adjuvant balloon dilation was performed in 13 limbs and stenting in 5., Results: There was initial technical and anatomical success in 34 procedures (94%), and 24 technically successful procedures persisted at mean follow-up of 16.5 months, although 1 limb required major amputation. Three failures were due to stenosis requiring further intervention, and 9 were due to occlusion. Failure led to no further intervention in 2, amputation in 1, further endovascular intervention in 5, and open surgical reconstruction in 4 limbs. After further treatment, 29 limbs are patent with no return of symptoms, 3 are occluded, and 4 have required amputation, all for initial presentation with critical ischemia. Life-table analyses calculate primary and secondary patency rates of 61% and 67% and a clinical success rate of 56% at 12 months., Conclusions: Atherectomy using the Auth Rotablator provides acceptable results, but its role in comparison to other endovascular techniques is still to be defined.

Purpose: To determine if atherectomy using the transluminal endarterectomy catheter (TEC) is an effective endoluminal therapy for infrainguinal occlusive disease., Methods: Three surgeons used the TEC for 144 infrainguinal atherectomy procedures in 133 patients. The indications were severe claudication in 83, critical ischemia in 56, and graft stenosis in 5 limbs. The pathology was stenosis in 36 and occlusion in 105 limbs. Balloon dilation was also performed in 109 and stenting in 17 limbs., Results: There was initial technical and anatomic success in 124 (86%) procedures. There were 67 technically successful procedures at mean follow-up of 19 months, although 3 of these limbs with gangrene and extensive distal disease required major amputation. There were 26 failures due to stenosis leading to further intervention and 51 due to occlusion. Twenty of these cases were managed conservatively, 21 were treated with repeat endovascular intervention, 31 with bypass grafting, and 5 with amputation. Repeat intervention in 52 limbs resulted in 36 with patent arteries, 10 that are occluded, and 6 that required amputation. Thirteen of the 14 amputations were for limbs with critical ischemia, but 1 was in a patient with claudication. Life-table analysis showed that the primary patency rate was 51%, the assisted primary patency rate was 61%, and the secondary patency rate was 75% at 15 months. The clinical success rate was 49%, and the salvage rate for limbs with critical ischemia was 78% at 12 months. Univariate log-rank testing showing no significant differences according to the clinical presentation of pathology, but results were worse for lesions > 5 cm long due to more frequent immediate failures. However, multivariate Cox regression analysis showed that results were significantly worse for critical ischemia than for claudication, stenosis compared to occlusions, for limbs with poor runoff, for operations performed by percutaneous rather than an open approach, and for those performed more recently., Conclusions: TEC atherectomy may have a place in selected patients, but the optimal circumstances for its use and long-term efficacy require further study.

Multivariate Cox regression analysis of patency rates for 750 consecutive femorodistal autogenous vein graftings for chronic lower limb ischemia showed that significant independent prognostic covariates were the type of graft (long saphenous or arm vein), presence of diabetes, and absence of a past history of myocardial ischemia. Analysis assumes that patients withdrawn with patent grafts due to death or loss to follow-up would have followed the same course as those who remain, and the degree to which this could distort results was studied. Patients who died with patent grafts were more likely to have had past myocardial ischemia and critical lower limb ischemia. Cox regression analysis for 600 operations after excluding patients who died with patent grafts then showed that significant independent covariates were the type of graft (long saphenous or arm vein) and indication (claudication or critical ischemia); then age, sex, hypertension, diabetes, myocardial ischemia, date of operation, surgeon, site of distal anastomosis, or first compared to repeat operations had no significant influence. Cox regression analysis helps determine which covariates influence graft patency rates, but results are affected by censored data, particularly from patients who die with patent grafts.

Using the Family Health Scale, Part I of an instrument developed for this study, two randomly selected groups of certified family therapists rated either nonfundamentalist or fundamentalist families in therapy on eight recognized indicators of family health. Factor analysis yielded eight factors accounting for 66% of the variance between groups. Cannonical discriminant function analysis revealed that therapists rated fundamentalist families as significantly less healthy on three of the eight factors and more healthy on one factor. Part II of this instrument, the Religion Impact Scale assessed the effects of church community and church teachings upon families. For fundamentalists, the church and concomitant belief system had a significant impact upon family organization and functioning. Theoretical and clinical implications of these findings are discussed.

Neurogenic claudication is characterized by sensory symptoms which appear during exercise or while maintaining a fixed posture. They are paraesthetic in quality, may be associated with 'march' phenomena, and patients may have bowel and bladder disturbance. The problem is most commonly secondary to lumbar canal stenosis (LCS) but rarely due to aortic disease, as shown in this case report. This report concerns a 66 year old woman who presented with symptoms of paraesthesia radiating from the buttocks to the thigh and, intermittent loss of bladder and bowel function, all associated with walking. There were no associated symptoms of vascular claudication. Clinically, there was evidence of aorto-iliac obstruction with absence of femoral pulses and a vascular index of 0.4 at both ankles. Neurological examination was normal at rest but the left ankle jerk was absent immediately after exercise. Myelogram and computerized tomographic (CT) scan were normal. An aortogram revealed a very tight irregular stenosis of the aorta at the level of the renal and mesenteric arteries. Very few lumbar vessels were seen. An aortic endarterectomy via a thoraco-abdominal approach was performed and an aortobifemoral graft inserted. The patient's symptoms resolved following this procedure. We postulate that her symptoms were caused by a 'steal' from the blood supply to the cauda equinda due to the severe athromatous disease of her upper abdominal aorta.

One large Australian family with X-linked retinal dystrophy was found to have extreme clinical variability in the hemizygotes. One member had the typical rod-cone disease, three had the cone-rod pattern and one had macroscopic changes in the macular area only, but with low potentials in the ERG. The locus for the disease was found to be distal to L1.28 at Xp21, the site for RP3. From a study of case histories reported it seems that clinical variability can be a common feature of X-linked retinitis pigmentosa (XLRP) with the locus at Xp11.3 (RP2) or at Xp21 (RP3), and this family may well be categorized as XLRP.

We studied the clinical appearance and inheritance in five families with X-linked megalocornea. Affected male subjects had corneal diameters between 13.0 and 16.5 mm. Arcus juvenilis, mosaic corneal dystrophy, and cataracts were found only in adult affected male subjects. No carrier female abnormality was identified. The gene locus for the X-linked form is in the region Xq12-q26. This is near the locus described for Aarskog (facial-digital-genital) syndrome, Xq12-13.

The effects of posture and sleep on the pharmacokinetics of paracetamol (acetaminophen) 500 mg and its metabolites were studied in 8 healthy men. The mean residence times for paracetamol or its metabolites were significantly altered by change in posture or by sleep, whereas other pharmacokinetic parameters were unchanged. The change in mean residence time is consistent with a faster absorption of paracetamol during ambulation. The present data suggest that the proposed posture-related changes in volume of distribution do not exist, and that there is no pharmacokinetic basis for a headache being relieved by taking paracetamol and lying down.

A linkage analysis has been performed on three Australian families segregating for autosomal dominant retinitis pigmentosa (ADRP). No evidence of linkage has been found in any of the pedigrees studied between the locus D3S47 and the gene for ADRP. The D3S47 locus was found to show very close linkage with the ADRP gene in a large Irish pedigree. Our study together with a similar report on a British family indicates that there is genetic heterogeneity in this disease.

In an attempt to map the gene(s) responsible for autosomal dominant retinitis pigmentosa (ADRP), the technique of reverse genetics was used on a large multigenerational Australian pedigree. The family demonstrated a form of the disease which appears to be less severe than that observed in the Irish pedigree. It was typed for 10 restriction fragment length polymorphism (RFLP) markers on chromosome 1. The data from the linkage study was analysed using the programs LIPED 3; six markers gave informative results. The ADRP gene was excluded from this family from 102 cM using previously prepared chromosome 1 maps. This accounts for 36% of chromosome 1 which is estimated to be the longest human chromosome.

Multilocus linkage analysis of 62 family pedigrees with X chromosome-linked retinitis pigmentosa (XLRP) was undertaken to determine the presence of possible multiple disease loci and to reliably estimate their map location. Multilocus homogeneity tests furnished convincing evidence for the presence of two XLRP loci, the likelihood ratio being 6.4 x 10(9):1 in favor of two versus a single XLRP locus and gave accurate estimates for their map location. In 60-75% of the families, location of an XLRP gene was estimated at 1 centimorgan distal to OTC, and in 25-40% of the families, an XLRP locus was located halfway between DXS14 (p58-1) and DXZ1 (Xcen), with an estimated recombination fraction of 25% between the two XLRP loci. There is also good evidence for a third XLRP locus, midway between DXS28 (C7) and DXS164 (pERT87), supported by a likelihood ratio of 293:1 for three versus two XLRP loci.

Restriction fragment length polymorphism studies and gene dosage analysis using the intragenic probes pERT87 were used to detect deletions in potential carriers in a family with Duchenne muscular dystrophy in which the only affected male was deceased. Two females were found to have inherited the paternal pERT87 alleles but not the maternal alleles, suggesting that they have inherited the pERT87 deletion from their mothers. The hybridization signals of pERT87 from these two females upon gene dosage analysis also suggested that they had a single copy of pERT87. The chorionic villi of a male fetus from one of these two females was found to be deleted for pERT87, suggesting that it was affected. This result confirmed the carrier status of the mother.

The maternal inheritance in Leber optic atrophy suggests that it may be caused by a cytoplasmic or mitochondrial defect. However, the strong male bias and the strict tissue specificity can not be readily explained by a single mitochondrial gene defect alone. Wallace suggested a hypothesis that the disease could be the result of an interaction between an X-linked gene and a mitochondrial DNA defect. Linkage relationships between Leber optic atrophy and 15 X-chromosome markers were analyzed in three large Tasmanian families. The results of two-point linkage analysis showed no close linkage between Leber optic atrophy and any of the 15 markers. The results of multipoint linkage analysis suggested the exclusion of the assumed X-linked gene from almost the whole X chromosome in these families.

Carbon fibre patches were inserted as prostheses into the dorsal lumbar fascia of rabbits. Their incorporation into the tissues was observed over a period of 15 weeks, and their mechanical properties were compared with those of implants made of a conventional Mersilene mesh. Although the mechanical properties of carbon fibre patches are initially poor, the development of a superior connective tissue response after several weeks suggests that a layered composite of carbon fibre and Mersilene with the latter giving initial strength may provide a useful material for clinical use as a hernia prosthesis.

Linkage analysis was carried out in three large multigenerational kindreds with X-linked retinitis pigmentosa using DNA markers on Xp. About 10% recombination has been found between the retinitis pigmentosa locus (RP2) and the marker locus DXS7, assigned to band Xp11.3, which was reported earlier to be closely linked to RP2 in several independent families. In the kindreds described in this paper, however, RP2 shows close linkage and no recombination with the marker loci OTC and DXS148, both assigned to Xp21, indicating that, contrary to previous linkage studies, there is evidence of an RP locus distal to DXS7. This suggests that X-linked retinitis pigmentosa is genetically heterogeneous, i.e., caused by mutations at different loci.

Duchenne muscular dystrophy (DMD) is an X-linked recessive genetic disorder for which the biochemical defect is as yet unknown. Recently, two cloned segments of human X-chromosome DNA have been described which detect structural alterations within or near the genetic locus responsible for the disorder. Both of these cloned segments were described as tightly linked to the locus and were capable of detecting deletions in the DNA of boys affected with DMD. In an attempt to determine more precisely the occurrence of these deletions within a large population of DMD patients and the accuracy of one of the segments, DXS164 (pERT87), in determining the inheritance of the DMD X chromosome, the subclones 1, 8 and 15 were made available to many investigators throughout the world. Here we describe the combined results of more than 20 research laboratories with respect to the occurrence of deletions at the DXS164 locus in DNA samples isolated from patients with DMD and Becker muscular dystrophy (BMD). The results indicate that the DXS164 locus apparently recombines with DMD 5% of the time, but is probably located between independent sites of mutation which yield DMD. The breakpoints of some deletions are delineated within the DXS164 locus, and it is evident that the deletions at the DMD locus are frequent and extremely large.

The pharmacokinetics of amoxycillin in normal male volunteers was studied during the states of bedrest, sleep and ambulation. The absorption and disposition of amoxycillin in ambulatory subjects was found to be comparable to that reported previously by other workers. Serum amoxycillin concentrations were found to be significantly greater during ambulation than during bedrest and sleep. The difference in serum levels resulted from an increased apparent total serum clearance and amoxycillin renal clearance during bedrest and sleep compared to ambulation. No significant differences in the clearance was found between the states of bedrest and sleep. The change in renal clearance of amoxycillin during ambulation was attributed to a diminished renal blood flow. Although the terminal half-life of amoxycillin did not differ significantly, the apparent volume of distribution appears to be much greater during bedrest and sleep than during ambulation. This difference could be explained pharmacokinetically using a two compartment model. No significant difference was found between the rates of absorption of amoxycillin as reflected by the lag time and time to peak serum amoxycillin. The actual values for these parameters would suggest, however, that the absorption of amoxycillin is faster during ambulation than in bedrest and that the absorption rate during sleep is slowest. The clinical implications of the effect of posture and sleep on the pharmacokinetics of amoxycillin are discussed.

This paper describes two cases of true atheromatous aneurysm formation within reversed autogenous saphenous vein used for femoropopliteal bypass graft. We note the rarity of this complication and review the literature for true aneurysm formation within vein grafts used for this and other bypass procedures.

Six vascular surgeons independently examined 44 legs in patients with suspected peripheral arterial disease. Each surgeon recorded whether the femoral and popliteal pulses were present or absent, and if thought to be present, whether they were normal or reduced in amplitude. Interobserver agreement was determined by calculating both observed agreement (Po) and agreement after correction for chance (kappa-k). The results were calculated both for each possible pair of surgeons and as an overall value for all possible pairs combined. Agreement as to whether pulses were present or absent was significantly better than expected by chance but was only moderately good (overall kappa for femoral pulse = 0.53, and overall kappa for popliteal pulse = 0.52). More often than not, agreement as to whether the pulses were normal or reduced was no better than expected by chance (overall kappa for femoral pulse = 0.15, and overall kappa for popliteal pulse = 0.01). For each assessment, agreement was no better for the more experienced than the less experienced pairs of surgeons. The results indicate that more objective methods than pulse palpation are required to determine whether there is significant disease in the aorto-iliac and femoro-popliteal arterial segments.

Extraperitoneal unilateral iliac artery bypass was used to treat chronic lower limb ischaemia in 105 patients (110 operations). This represented 20% of all operations for aorto-iliac disease. Unilateral iliac bypass was the preferred primary procedure for 99 operations, and was used to correct complications in one limb of a prior aortic bifurcation graft in the other 11. Ipsilateral femoropopliteal vein grafts were also performed in 45 legs (43%), prior to the iliac bypass in 18, as a synchronous operation in nine, and at a later date in 18 legs. This was a much higher proportion of combined operations than for patients by aortic bifurcation grafts (12%). Only 5 patients later required further proximal surgery, one for a blocked graft and four for contralateral iliac disease. The cumulative patency rate in surviving patients was 91% at 3 years. For the claudicants and for iliofemoral bypass operations, only one graft occluded, within 5 years, and no grafts occluded for operations where the superficial femoral artery was patent. The cumulative patency rates at 3 years were 85% for patients with critical ischaemia, 82% for ilioprofunda bypass operations, and 88% for operations where the superficial femoral artery was occluded. The cumulative foot-salvage rate in surviving patients initially treated for critical ischaemia was 77% at 3 years. The cumulative survival rate was 90% at 3 years. Extraperitoneal unilateral iliac bypass is now preferred as the primary operation for patients with apparent unilateral iliac disease causing severe ischaemia, if balloon dilatation is not appropriate or has failed.

Deletion is a common cause of Duchenne muscular dystrophy (DMD). Field-inversion gel electrophoresis, in conjunction with Southern blot hybridization, was used to detect large SfiI DNA fragments in the DMD locus. Two unrelated boys with DMD were found to have abnormal sized DNA fragments resulting from deletions. Some of the female relatives of these patients were also shown by this method to have deletions in the DMD locus.

As part of a patient care and DNA research programme commenced in 1985, a number of DNA markers on the short arm of the X chromosome have been used to demonstrate restriction fragment length polymorphisms (RFLPs) segregating with the X-pigmentary retinal dystrophy (X-linked retinitis pigmentosa) gene. The analysis of the segregation of the RFLPs in 3 kindreds enables carrier detection, to a high degree of probability, in females at risk who are not manifesting symptoms and signs.

The aim of this paper is to assess the in situ technique of saphenous vein femoropopliteal (and femorotibial) bypass for limb salvage, and to compare it with the reversed vein method of bypass. In our 3-year study, we have operated on 50 cases resulting in a graft patency and limb salvage rate of 78 per cent at 18 months and 72 per cent overall. There was a 2 per cent perioperative and 10 per cent overall mortality. Graft thrombosis was associated with a variety of factors, mostly notably a small vein (les than 4 mm), a low calf vessel anastomosis, wound sepsis and progressive proximal (inflow) disease. However, the strongest correlation was that between graft thrombosis and the extent of distal disease, as 11 of 12 cases with thrombosed grafts had grade 2 or 3 run-off. In our experience the in situ technique offers haemodynamic and technical advantages over the reversed vein method of performing straightforward femoropopliteal bypass. Moreover, the in situ technique has wider application in that it allows a smaller vein (greater than 2.5 mm) to be used and also makes anastomosis to a small calf vessel easier. In this series, 16 per cent of cases would have been considered unsuitable for the reversed vein method if 4 mm was accepted as the lower limit of size for a reversed vein graft.