Recommendations for laboratory workflow that better support centralised amalgamation of genomic variant data: findings from CanVIG-UK national molecular laboratory survey

BACKGROUND

National and international amalgamation of genomic data offers opportunity for research and audit, including analyses enabling improved classification of variants of uncertain significance. Review of individual-level data from National Health Service (NHS) testing of cancer susceptibility genes (2002-2023) submitted to the National Disease Registration Service revealed heterogeneity across participating laboratories regarding (1) the structure, quality and completeness of submitted data, and (2) the ease with which that data could be assembled locally for submission.

METHODS

In May 2023, we undertook a closed online survey of 51 clinical scientists who provided consensus responses representing all 17 of 17 NHS molecular genetic laboratories in England and Wales which undertake NHS diagnostic analyses of cancer susceptibility genes. The survey included 18 questions relating to 'next-generation sequencing workflow' (11), 'variant classification' (3) and 'phenotypical context' (4).

RESULTS

Widely differing processes were reported for transfer of variant data into their local LIMS (Laboratory Information Management System), for the formatting in which the variants are stored in the LIMS and which classes of variants are retained in the local LIMS. Differing local provisions and workflow for variant classifications were also reported, including the resources provided and the mechanisms by which classifications are stored.

CONCLUSION

The survey responses illustrate heterogeneous laboratory workflow for preparation of genomic variant data from local LIMS for centralised submission. Workflow is often labour-intensive and inefficient, involving multiple manual steps which introduce opportunities for error. These survey findings and adoption of the concomitant recommendations may support improvement in laboratory dataflows, better facilitating submission of data for central amalgamation.

Germline mismatch repair (MMR) gene analyses from English NHS regional molecular genomics laboratories 1996-2020: development of a national resource of patient-level genomics laboratory records

OBJECTIVE

To describe national patterns of National Health Service (NHS) analysis of mismatch repair (MMR) genes in England using individual-level data submitted to the National Disease Registration Service (NDRS) by the NHS regional molecular genetics laboratories.

DESIGN

Laboratories submitted individual-level patient data to NDRS against a prescribed data model, including (1) patient identifiers, (2) test episode data, (3) per-gene results and (4) detected sequence variants. Individualised per-laboratory algorithms were designed and applied in NDRS to extract and map the data to the common data model. Laboratory-level MMR activity audit data from the Clinical Molecular Genetics Society/Association of Clinical Genomic Science were used to assess early years' missing data.

RESULTS

Individual-level data from patients undergoing NHS MMR germline genetic testing were submitted from all 13 English laboratories performing MMR analyses, comprising in total 16 722 patients (9649 full-gene, 7073 targeted), with the earliest submission from 2000. The NDRS dataset is estimated to comprise >60% of NHS MMR analyses performed since inception of NHS MMR analysis, with complete national data for full-gene analyses for 2016 onwards. Out of 9649 full-gene tests, 2724 had an abnormal result, approximately 70% of which were (likely) pathogenic. Data linkage to the National Cancer Registry demonstrated colorectal cancer was the most frequent cancer type in which full-gene analysis was performed.

CONCLUSION

The NDRS MMR dataset is a unique national pan-laboratory amalgamation of individual-level clinical and genomic patient data with pseudonymised identifiers enabling linkage to other national datasets. This growing resource will enable longitudinal research and can form the basis of a live national genomic disease registry.

Targeted next generation sequencing reveals a common genetic pathway for colorectal cancers with chromosomal instability and those with microsatellite and chromosome stability

INTRODUCTION

Microsatellite stable sporadic colorectal cancers (CRCs) can be classified as either tumours with chromosomal instability (CIN+) or tumours that are 'Microsatellite and Chromosomal Stable' (MACS). The CIN + tumours are aneuploid whilst MACS are near-diploid; little else is known about their differences. We compared the mutation profiles of CIN + and MACS CRCs.

METHOD

Targeted Next Generation Sequencing for mutation in 26 driver genes (TruSight-26 kit) was undertaken in 46 CIN + and 35 MACSCRCs. Tumours were compared for mutation frequency, allelic imbalance and clonal heterogeneity.

RESULTS

Mutations were detected in 58% genes and, overall, mutation in driver genes was at expected frequencies. Comparison of classes revealed similar mutation frequencies in most genes and allelic imbalance atAPC and TP53. Differences were seen in mutation frequency in KRAS (41% CIN+ vs 68% MACS, p = 0.015) and GNAS (0% CIN+ vs 12% MACS, p = 0.032). Twenty percent CIN + CRCs harboured mutations only in TP53 - a profile not seen in the MACS tumours (p = 0.009). None of the differences were significant after multiple testing corrections.

CONCLUSIONS

The mutation profiles of CIN and MACS CRCs are similar. The events allowing aneuploidy (or forcing retention of diploidy) remain unknown.

Perfusion of muscle flaps independent of the anatomical vascular pedicle: Pedicle autonomy

INTRODUCTION

Free muscle flaps are being used more commonly for complex lower limb reconstruction. Up to 33% of flaps used to reconstruct lower limb trauma will require an orthopaedic procedure after reconstruction. To date there have been only case reports detailing the variable survival of muscle flaps after actual or simulated pedicle injury and the process and timeframe of neovascularisation remains undefined. We aim to show that perfusion of a muscle flap is possible after injury to its anatomical vascular pedicle.

METHODS

Pedicled muscle flaps were raised and transposed to a cutaneous inset on the chest wall in a rodent model. Each flap was subjected to simulated pedicle injury at a variable time. Allocation was by computer randomisation. Flap perfusion was assessed before and after pedicle injury followed 48 h later by sacrifice of the animal and static angiography of the flaps.

RESULTS

By the 21st day after inset, all flaps survived simulated pedicle injury. Prior to this, flap survival was significantly lower (p = 0.017, Fisher's Exact Test). Clinical signs at the time of pedicle injury did not predict flap survival. Most new vessels form at the distal part of the inset (p < 0.01, ANOVA). The total number does not change with time (p = 0.82, ANOVA). New vessels anastomose preferentially with skin. The fall in perfusion after pedicle ligation was significant for all groups except the day 35 group (p = 0.53).

CONCLUSIONS

Muscle flaps can perfuse after an injury to the anatomical vascular pedicle through neovascularisation at the inset. These new vessels are evident early but may not function adequately to perfuse the flap. Regional variations in neovascularisation suggest that a gradient of ischaemia drives this process. Inset at the cutaneous level is important, which has implications for buried muscle flaps. The correlation between change in flap perfusion after pedicle injury and flap necrosis suggests a role for the former in determining the capacity of a muscle flap to tolerate a pedicle injury and thereby the approach to re-raising it.

X-linked retinoschisis: clinical phenotype and RS1 genotype in 86 UK patients

BACKGROUND

Inactivating mutations of the gene RS1 lead to X-linked retinoschisis, a progressive retinal dystrophy characterised by schisis within the inner layers of the neuroretina. The mutation spectrum is large and the phenotype variable.

AIM

To determine whether there is a correlation between mutation type and disease severity.

METHODS

We identified the causative mutation in 86 affected patients and examined each of these patients in detail. Different categories of mutation were compared for each phenotypic characteristic.

RESULTS

We found a reduction in visual acuity with increasing age and worsening macular pathology in patients over 30 years old (p < or = 0.001), but there was no correlation between mutation type and severity of disease. Furthermore, we found a wide variation in phenotype even within families.

CONCLUSIONS

Identifying the causative mutation in patients with X-linked retinoschisis is helpful in confirming diagnosis and in counselling of family members but cannot be used to predict prognosis for an individual patient.

Is Optic Nerve Fibre Mis-Routing a Feature of Congenital Stationary Night Blindness?

PURPOSE

To determine whether patients with congenital stationary night blindness (CSNB) have electrophysiological evidence of optic nerve fibre mis-routing similar to that found in patients with ocular albinism (OA).

METHOD

We recorded the Pattern Onset VEP using a protocol optimised to detect mis-routing of optic nerve fibres in older children and adults. We tested 20 patients (age 15-69 yrs) with X-linked or autosomal recessive CSNB, 14 patients (age 9-56 yrs) with OA and 13 normally pigmented volunteers (age 21-66 yrs). We measured the amplitude and latency of the CI component at the occipital midline and over left and right occipital hemispheres. We also assessed the computed inter-hemispheric "difference" signal. Subjects with CSNB were classified as having the "complete" or "incomplete" phenotype on the basis of their ERG characteristics. Members of X-linked CSNB pedigrees underwent mutation screening of the NYX and CACNA1F genes.

RESULTS

CI was significantly smaller over the ipsilateral hemisphere and more prominent over the contralateral hemisphere in OA patients compared with both controls and CSNB patients. In CSNB patients CI response amplitudes were not significantly different from controls but peak latency was prolonged at all three electrodes compared with controls. The inter-hemispheric "difference" signal was abnormal for the OA group but not for the CSNB group. Contralateral dominance of CI could be identified in the majority of OA patients and the "difference" signal was opposite in polarity for left compared with right eye stimulation in every patient in this group. Only 3 of 20 patients with CSNB showed significant inter-hemispheric asymmetry similar to that seen in the OA patients. All 3 CSNB patients with evidence for optic nerve fibre mis-routing had X-linked pedigrees: 2 had an identified mutation in the NYX gene but no mutation in either the NYX or CACNA1F genes was identified in the third. VEP evidence of optic nerve fibre mis-routing was present in 3 of the 11 subjects with "complete" phenotype and none of the 9 patients with "incomplete" phenotype CSNB.

CONCLUSION

Mis-routing of optic nerve fibres does occur in CSNB but we found evidence of it in only 15% of our patients.

Blue cone monochromatism: a phenotype and genotype assessment with evidence of progressive loss of cone function in older individuals

AIM

To perform a detailed clinical and psychophysical assessment of the members of three British families affected with blue cone monochromatism (BCM), and to determine the molecular basis of disease in these families.

METHODS

Affected and unaffected members of three families with BCM were examined clinically and underwent electrophysiological and detailed psychophysical testing. Blood samples were taken for DNA extraction. The strategy for molecular analysis was to amplify the coding regions of the long wavelength-sensitive (L) and middle wavelength-sensitive (M) cone opsin genes and the upstream locus control region by polymerase chain reaction, and to examine these fragments for mutations by direct sequencing.

RESULTS

We have confirmed the reported finding of protan-like D-15 arrangements of patients with BCM. In addition, we have demonstrated that the Mollon-Reffin (MR) Minimal test is a useful colour-discrimination test to aid in the diagnosis of BCM. Affected males were shown to fail the protan and deutan axes, but retained good discrimination on the tritan axis of the MR test, a compelling evidence for residual colour vision in BCM. This residual tritan discrimination was also readily detected with HRR plates. In two families, psychophysical testing demonstrated evidence for progression of disease. In two pedigrees, BCM could be linked to unequal crossovers within the opsin gene array that resulted in a single 5'-L/M-3' hybrid gene, with an inactivating Cys203Arg mutation. The causative mutations were not identified in the third family.

CONCLUSIONS

The MR test is a useful method of detecting BCM across a wide range of age groups; residual tritan colour discrimination is clearly demonstrated and allows BCM to be distinguished from rod monochromatism. BCM is usually classified as a stationary cone dysfunction syndrome; however, two of our families show evidence of progression. This is the first report of progression associated with a genotype consisting of a single 5'-L/M-3' hybrid gene carrying an inactivating mutation. We have confirmed that the Cys203Arg inactivating mutation is a common sequence change in blue cone monochromats.

Autonomous activity of CaMKII is only transiently increased following the induction of long-term potentiation in the rat hippocampus

A major role has been postulated for a maintained increase in the autonomous activity of CaMKII in the expression of long-term potentiation (LTP). However, attempts to inhibit the expression of LTP with CaMKII inhibitors have yielded inconsistent results. Here we compare the changes in CaMKII autonomous activity and phosphorylation at Thr286 of alphaCaMKII in rat hippocampal slices using chemical or tetanic stimulation to produce either LTP or short-term potentiation (STP). Tetanus-induced LTP in area CA1 requires CaMKII activation and Thr286 phosphorylation of alphaCaMKII, but we did not observe an increase in autonomous activity. Next we induced LTP by 10 min exposure to 25 mM tetraethyl-ammonium (TEA) or 5 min exposure to 41 mM potassium (K) after pretreatment with calyculin A. Exposure to K alone produced STP. These protocols allowed us to monitor temporal changes in autonomous activity during and after exposure to the potentiating chemical stimulus. In chemically induced LTP, autonomous activity was maximally increased within 30 s whereas this increase was significantly delayed in STP. However, in both LTP and STP the two-fold increase in autonomous activity measured immediately after stimulation was short-lived, returning to baseline within 2-5 min after re-exposure to normal ACSF. In LTP, but not in STP, the phosphorylation of alphaCaMKII at Thr286 persisted for at least 60 min after stimulation. These results confirm that LTP is associated with a maintained increase in autophosphorylation at Thr286 but indicate that a persistent increase in the autonomous activity of CaMKII is not required for the expression of LTP.

Full-field ERG responses recorded with skin electrodes in paediatric patients with retinal dystrophy

PURPOSE

Assess ERG responses recorded with skin electrodes in children with retinal dystrophies.

METHOD

ERG responses were recorded using skin electrodes in 17 healthy children and 43 paediatric patients with retinal dystrophy. Subjects were aged 4-14 years. ERG responses were recorded to full-field stimuli similar to those recommended in the ISCEV standard. The type of retinal dystrophy was classified on the basis of standard clinical criteria and the ERG responses were compared with those of the age-matched controls.

RESULTS

ERG responses were abnormal in every patient. The specific type of ERG abnormality was also consistent with the clinical findings in the majority of patients. Rod responses were abnormal in every patient with a rod-cone dystrophy and cone responses were also abnormal in the majority of patients. Those patients with cone dystrophy or rod monochromatism had normal or near normal rod responses but sub-normal or absent cone responses. Patients with CSNB or XLRS had a sub-normal b-wave but normal amplitude a-wave.

CONCLUSION

ERGs can be recorded successfully with skin electrodes in paediatric patientsand responses can aid the diagnosis of the type of retinal dystrophy.

Oligocone trichromacy: a rare and unusual cone dysfunction syndrome

AIM

To describe the phenotype of a case series of six patients with oligocone trichromacy.

METHODS

The six affected individuals underwent an ophthalmological examination, electrophysiological testing and detailed psychophysical assessment.

RESULTS

All six affected patients had a history of moderately reduced visual acuity (6/12 to 6/24) from infancy, not improved by full spectacle correction. They complained of mild photophobia and they were not aware of any colour vision deficiency. They had no nystagmus and fundi were normal. Electrophysiological testing revealed either absent/profoundly reduced cone flicker responses or preserved but delayed and mildly reduced flicker responses. Colour vision was found to be within normal limits, but some patients showed mildly elevated discrimination thresholds along all axes.

CONCLUSION

The largest case series to date of patients with oligocone trichromacy is presented. The electrophysiological findings suggest that there may be more than one disease mechanism. The mode of inheritance is likely to be autosomal recessive, and while previous reports have suggested that this disorder is stationary, in one of these families there is clinical evidence of progression.

Genotype-phenotype correlation in British families with X linked congenital stationary night blindness

AIM

To correlate the phenotype of X linked congenital stationary night blindness (CSNBX) with genotype.

METHODS

11 CSNB families were diagnosed with the X linked form of the disease by clinical evaluation and mutation detection in either the NYX or CACNA1F gene. Phenotype of the CSNBX patients was defined by clinical examination, psychophysical, and standardised electrophysiological testing.

RESULTS

Comprehensive mutation screening identified NYX gene mutations in eight families and CACNA1F gene mutations in three families. Electrophysiological and psychophysical evidence of a functioning but impaired rod system was present in subjects from each genotype group, although the responses tended to be more severely affected in subjects with NYX gene mutations. Scotopic oscillatory potentials were absent in all subjects with NYX gene mutations while subnormal OFF responses were specific to subjects with CACNA1F gene mutations.

CONCLUSIONS

NYX gene mutations were a more frequent cause of CSNBX than CACNA1F gene mutations in the 11 British families studied. As evidence of a functioning rod system was identified in the majority of subjects tested, the clinical phenotypes "complete" and "incomplete" do not correlate with genotype. Instead, electrophysiological indicators of inner retinal function, specifically the characteristics of scotopic oscillatory potentials, 30 Hz flicker and the OFF response, may prove more discriminatory.

A clinical and molecular genetic study of a rare dominantly inherited syndrome (MRCS) comprising of microcornea, rod-cone dystrophy, cataract, and posterior staphyloma

AIM

To phenotype and genetically map the disease locus in a family presenting with autosomal dominant microcornea, rod-cone dystrophy, cataract, and posterior staphyloma.

METHODS

Six affected and three unaffected members of the pedigree were examined. All individuals provided a history and underwent a full clinical examination with A-scan and B-scan ultrasonography and electrophysiological testing where appropriate. PCR based microsatellite marker genotyping using a positional candidate gene approach was then performed on DNA samples extracted from venous blood provided by each subject.

RESULTS

The disorder is inherited as an autosomal dominant trait with variable expressivity and has a complex phenotype. Affected individuals had bilateral microcornea, pulverulent-like lens opacities, a rod-cone dystrophy and posterior staphyloma (MRCS). Using a positional candidate gene approach, the authors have evidence suggestive of linkage of this disorder to a region on 11q13 within the nanophthalmos 1 (NNO1) genetic interval. The small family size militates against achieving a LOD score of 3, but the haplotype data and the position of the putative MRCS locus within a known nanophthalmos locus are suggestive of linkage. A candidate gene within this region (ROM1) was screened and no mutations were found in affected members of the family.

CONCLUSION

This rare developmental disorder has some phenotypic similarities to nanophthalmos and possibly maps to a locus within the genetic interval encompassing the NNO1 locus. Screening of candidate genes within this region continues.

Progressive nodular histiocytosis in a child with a hypothalamic tumor

We report a 13-year-old girl with multiple cutaneous histiocytic lesions, precocious puberty, growth hormone deficiency and a hypothalamic tumour. We conclude that she has progressive nodular histiocytosis, but this case illustrates the difficulty in differentiating the type II histiocytoses.

Idiopathic central pontine myelinolysis in childhood

Central pontine myelinolysis (CPM) is rare in childhood with only a few cases reported in world literature. We report a 7-year-old male who presented with acute ataxia, swallowing difficulties, dysarthria, and radiological features consistent with the disorder. He improved remarkably with oral prednisolone therapy and was almost back to normal by 2 weeks. A review of the literature is also included.

Imaging the upper airways

Radiological evaluation of the airway has been used as a screening tool and an adjunct to endoscopy for many years. It provides non-invasive data on the structure of the airway, often avoiding the risk of general anaesthesia. Standard radiographs provide some information on the intricate anatomy of the paediatric airway aided by fluoroscopy. More recently, CT and MRI are proving to have a valuable role and are approaching near endoscopic detail of airway anatomy. The purpose of this article is to highlight areas where radiology can aid in the evaluation of the airway of infants and children.

Mutations of the XLRS1 gene cause abnormalities of photoreceptor as well as inner retinal responses of the ERG

Intensity-series rod and cone ERGs were recorded in 19 patients with XLRS and 26 control eyes. All patients were examined by one ophthalmologist and diagnosed on the basis of fundus appearance and evidence of the disease in other males in the same family. Mutations in the XLRS1 gene have been identified in 15 of the patients. Dark-adapted ERGs were significantly different from controls for all test conditions and for both a-wave and b-wave responses. Abnormalities were detectable in all patients but there was considerable variation in the severity of abnormality. One third of the patients had the dark-adapted 'negative-wave' response typically associated with inner retinal disorder, but about one third showed only mild depression of the b-wave while the remainder had abnormally low a-waves in addition to depressed b-waves. Light-adapted responses were also affected and both a-wave and b-wave responses differed significantly from controls, but the 'negative-wave' response was not seen in any patient. The severity of the ERG abnormality did not correlate with the classification of fundus appearance or patient age suggesting that retinal function is relatively stable throughout life. The severity of ERG abnormalities did not correlate with the type of mutation and responses could differ between affected males within the same family. These results indicate considerable heterogeneity of ERG response without clinical, age or genetic correlate. The abnormal a-wave responses indicate that photoreceptor as well as inner retinal layer function may be affected in XLRS, at least in some patients.

Ophthalmic manifestations of trisomy 8 mosaic syndrome

Trisomy 8 mosaicism can present with a varied clinical picture. A significant number of cases have ocular manifestations. The most commonly reported in the literature have been corneal abnormalities and strabismus. We present a case of trisomy 8 mosaic syndrome with very different ophthalmic manifestations, some of which are previously unreported in the literature. The patient who was known to have trisomy 8 mosaic syndrome was referred with concerns about his visual abilities. He had a characteristic facial dysmorphism and other systemic features associated with this condition. Ophthalmic features included bilateral Duane's syndrome, bilateral myopic astigmatism, congenital pendular nystagmus, and macula hypoplasia. Electrodiagnostic tests confirmed extensive abnormality of cone function in both eyes. This case is discussed in relation to a review of the literature.

A Java-based multi-institutional medical information retrieval system

JAMI (Java-based Agglutination of Medical Information) is designed as a framework for integrating heterogeneous information systems used in healthcare related institutions. It is one of the implementations under the W3-EMRS project 1 aimed at using the World Wide Web (Web) to unify different hospital information systems. JAMI inherited several design decisions from the first W3-EMRS implementation described in, including using the Web as the communication infrastructure and HL7 as the communication protocol between the heterogeneous systems and the W3-EMRS systems. In addition, JAMI incorporates the growing Java technologies and has a more flexible and efficient architecture. This paper describes JAMI's architecture and implementation. It also present two instances of JAMI, one for the integration of different hospital information systems and another for the integration of two heterogeneous systems within a single hospital. Some important issues for the further development of JAMI, including security and confidentiality, data input and decision support are discussed.

Infantile presentation of X linked retinoschisis

Five infants who presented with nystagmus and/or strabismus were found to have bilateral highly elevated bullous retinoschisis involving the macula. Haemorrhage was present within the schisis cavity or the vitreous in four patients. The bullous retinoschisis eventually reattached spontaneously leaving pigment demarcation lines. A family history of X linked retinoschisis (XLRS) was known in two of the patients but in the other three subsequent investigation showed other male family members to be affected. It is important to recognise this uncommon presentation of XLRS so that the correct diagnosis is made and appropriate genetic counselling is given. Surgical treatment is not usually indicated and the visual prognosis is better than the initial appearance may suggest.

Evaluation of clomiphene citrate and human chorionic gonadotropin treatment: a prospective, randomized, crossover study during intrauterine insemination cycles

OBJECTIVE

To test the hypothesis that in couples undergoing IUI, actively managed cycles using clomiphene citrate (CC) stimulation, ultrasound monitoring, and hCG timing will result in increased pregnancy rate (PR) per cycle compared with unstimulated urinary LH-timed cycles.

PATIENTS

Fifty-six couples with unexplained infertility (n = 26) or male factor infertility (n = 30) participated in the study.

SETTING

Tertiary academic medical center.

DESIGN

Prospective, randomized, crossover. Couples were randomized initially to one of the two study groups (treatment A: LH-timed IUI; treatment B: CC-stimulated, hCG-timed IUI). If no pregnancy occurred, each couple alternated between the two regimens during subsequent cycles, up to a total of four cycles.

RESULTS

Twenty-nine couples completed the study and the analysis of 95 cycles revealed that among the male factor infertility group, one pregnancy occurred during the 26 cycles of each treatment group (PR per cycle of 3.9% for both treatment groups). In contrast, among the unexplained infertility group, there was a marked difference in the effect of treatments. During treatment A only one pregnancy occurred in 20 cycles (PR of 5% per cycle) whereas during treatment B, six pregnancies occurred in 23 cycles (PR of 26.1% per cycle).

CONCLUSIONS

If IUI is chosen as the treatment modality in unexplained infertility, the addition of active ovulation management that includes CC stimulation, ultrasound monitoring of folliculogenesis, and hCG timing of ovulation increases the PR per cycle. In couples with male infertility, PR per cycle is low and is apparently not affected by the addition of active ovulation management.

Patients' satisfaction survey: a review of in-patient attitudes towards care during a 12 month period

In order to assess the value of medical and nurse team meetings in a programme designed to improve the quality of care given on a general medical ward, a 33% sample of recent in-patients was asked to complete a questionnaire about the quality of care that they received from doctors and nurses. Regular meetings were convened to respond to criticisms and improve overall care. During the year of the programme there was no significant change in the quality of care as perceived by patients and it is clear that this approach to improving care is ineffective.

A prospective randomized study of pregnancy rates following intrauterine and intracervical insemination using frozen donor sperm

Cryopreserved sperm have lowered fertility when compared with fresh sperm in artificial insemination by donor programs. The purpose of this study was to compare pregnancy rates following intrauterine insemination (IUI) and intracervical insemination (ICI) with cryopreserved sperm in a prospective trial using the patient as her own control. A total of 154 patients were randomized into alternating treatment cycles and underwent 238 cycles of IUI and 229 cycles of ICI. The pregnancy rate per treatment cycle was 9.7% following IUI and 3.9% following ICI. Treatment outcome was influenced by patient age, ovulatory status, and endometriosis. Pregnancy success correlated well with the post-thaw survival of sperm and the number of motile cells inseminated. In spite of having normal semen parameters, some donors were found to have markedly reduced sperm fecundity. We conclude that IUI with cryopreserved sperm can be an effective treatment for couples with infertility, genetic indications, or other reasons.

Influence of induced hypotension and spinal distraction on feline spinal somatosensory evoked potentials

Spinal cord injury may occur during surgical correction of spinal deformity, which is performed frequently under hypotensive anaesthesia. We have investigated the interaction between pharmacologically induced hypotension and distraction on feline spinal cord function. Twelve anaesthetized cats were subjected to hypotension (mean arterial pressure (MAP) 60 mm Hg) using a mixture of sodium nitroprusside and trimetaphan (1:5). No significant changes were observed in somatosensory evoked potentials recorded at T11. In six cats distraction was applied at L2-3 in 2.5-mm increments up to 1 cm, while MAP was maintained at 100 mm Hg (normotensive group). The remaining cats were subjected to the same distraction procedure at an MAP of 60 mm Hg (hypotensive group). In the hypotensive group, a reduction in amplitude of evoked response occurred at significantly less distraction than in the normotensive group. These data indicate that the feline spinal cord is more sensitive to spinal distraction under hypotensive conditions.

Clinical evaluation of spinal cord monitoring in scoliosis surgery

The somatosensory evoked potential (SEP) is a technique that can be used to monitor sensory conduction within the spinal cord throughout the course of spinal surgery. The authors describe the technique, stimulation, and recording parameters, which most critically affect the success and reliability of monitoring trials. In addition, we show that in all 40 patients tested fully, the SEP results were in complete agreement with the clinical findings at the time of the wake-up test. In this series, there was no instance of a "false-positive" SEP result, or of the SEP failing to detect neural damage. Temporary, neurologic deficit occurred on two occasions, which are described in detail. These show that the SEP is rapid, enables neurologic complications to be detected at an early stage of surgery, and can identify lateralized problems. It is concluded that the technique may provide a clinically valuable method for continuous and prolonged monitoring of spinal cord function.