The impact of complications after vascular surgery in Veterans Affairs Medical Centers

The impact of perioperative complications on clinical outcomes and resource utilization was assessed for 8702 veterans who, during fiscal years 1991-1994, underwent vascular surgery procedures in DRGs 110 and 111, which include aortic and peripheral aneurysm repairs as well as renal artery and some peripheral vascular reconstructions. In-hospital mortality rate was 6.2% (537/8702). Mortality was 9.8% with any ICD-9-CM-coded complication vs 4.9% without (P < 0.001). Mortality was 28.9% in those with both cardiac and pulmonary complications, 11.0% with either cardiac or pulmonary complications, and 3.7% with neither cardiac nor pulmonary complications. Length of stay (LOS) was 25.8 +/- 21.9 days with any ICD-9-CM-coded complication vs 18.9 +/- 14.1 days without (P < 0.001). Further, RIS (Resource Intensity Scale), a measure of intensity of resource utilization, was greater in those with (3.01 +/- 0.81) vs without (2.76 +/- 0.70; P < 0.001) a complication. Pulmonary complications impacted LOS and RIS more adversely than cardiac. A logistic regression model of mortality indicated that increasing age [odds ratio (OR) 1.065], arrhythmia (OR 1.31), pneumonia (OR 2.52), surgical complications of the heart (OR 2.8), respiratory insufficiency (OR 4.75), stroke (OR 5.48), MI (OR 5.78), and acute renal failure (ARF, OR 9.58) were associated with increasing likelihood for death, whereas treatment in the largest, academically affiliated VAMCs (RPM 5) was associated with reduced mortality (OR 0.795). Increasing age, treatment in the largest affiliated (RPM 5) hospitals, arrhythmia, MI, CHF, any ICD-9-CM-coded complication, acute renal failure, respiratory insufficiency, pneumonia, and stroke progressively increased LOS by linear regression analysis, whereas surgical complications of the heart and postoperative death reduced LOS. Complications after vascular surgery have an adverse impact on perioperative mortality, length of stay, and utilization of resources.

A model for an integrated emergency medicine/trauma service

OBJECTIVE

To describe a model for an integrated multidisciplinary trauma service and to compare survival outcomes for patients resuscitated by either emergency medicine (EM) or surgical housestaff assigned to the trauma service.

METHODS

A prospective observational study was performed using injured patients evaluated in the trauma room at Hartford Hospital from July 1 through December 31, 1995. Inclusion criteria included an ICD-9-CM code of 800 through 959.9 and any of the following: transfer from another hospital, admission to the intensive care unit, hospitalization for > or = 23 hours, survival probability of < or = 90%, or Abbreviated Injury Score of > or = 3. Patients were excluded for burns necessitating transfer to a burn unit for definitive care, and for missing data elements that prevented a patient from being analyzed by the TRISS method. Data elements included mechanism of injury, Injury Severity Score, Revised Trauma Score, probability of survival, age, gender, and whether an EM resident was team leader. Patients in the EM cohort (group 1) were compared with patients for whom a surgical resident was team leader (group 2) for all data elements and for hospital survival. TRISS analysis was performed to evaluate outcomes in comparison with national norms.

RESULTS

After exclusions, 609 patients were left for analysis. There were 141 (30%) resuscitated with an EM resident as team leader. No significant difference was found for matched variables between the groups. Both groups had good comparability with the Major Trauma Outcome Study (MTOS) database baseline, with M scores of 0.949 and 0.942, respectively. Outcomes for both groups also compared favorably with the MTOS norm for survival, with Z scores of 2.38 and 2.35 for groups 1 and 2.

CONCLUSIONS

These results suggest that in this model of integrated EM/trauma service, equivalent survival outcomes occur whether EM or surgery housestaff act as team leaders.

Clinical analysis of the utility of repeat computed tomographic scan before discharge in blunt hepatic injury

OBJECTIVES

Nonoperative management of hemodynamically stable blunt hepatic injury has emerged as an acceptable and safe treatment. Surveillance of this population's injuries is costly. As a prelude to establishing practice guidelines, the utility of repeat computed tomographic (CT) scans was investigated.

METHODS

A retrospective study was conducted on 243 hepatic injuries. The CT scans of 95 patients managed nonoperatively who did not have ongoing transfusion requirements were reviewed and graded according to the American Association for the Surgery of Trauma (AAST) hepatic injury scale. Patients were grouped according to injury grade, assigned to two subgroups (patients with one CT scan versus more than one CT scan) and compared with respect to several physiologic and clinical variables.

RESULTS

Statistical analysis revealed no significant difference between subgroups with the same grade of injury. No significant difference was demonstrated between subgroups' length of stay.

CONCLUSIONS

No patients failed nonoperative treatment or succumbed to their injuries. Findings on repeat CT scan have not altered the decision to discharge the clinically stable patient having suffered a grade III or lower liver injury.

Lack of serum antibodies against glycoprotein E in pseudorabies virus-immune pigs infected with wild-type virus

OBJECTIVE

To examine whether pigs with solid immunity against pseudorabies virus (PRV) could harbor latent infection with wild-type PRV without developing antibodies against glycoprotein E (gE), which is used as a marker protein to differentiate pigs that have been vaccinated from pigs infected with wild-type PRV.

ANIMALS

Specific-pathogen-free pigs that were seronegative for antibodies to PRV.

PROCEDURE

Oropharyngeal swab specimens were collected, and virus content was measured, Serum samples were obtained 1 week before and 2 and 4 weeks after challenge exposure. Four weeks after challenge exposure, pigs were slaughtered; various tissues were collected for virus isolation, and DNA was analyzed by polymerase chain reaction.

RESULTS

Of the intranasally inoculated pigs, only 1 pig shed virus (for 1 day) but none developed antibodies directed against gE. Of the inoculated IM pigs, 3 pigs shed virus (for several days) and 5 developed antibodies directed against gE. One pig did not shed virus and did not develop detectable gE antibodies. However, variable amounts of wild-type virus DNA were detected in various tissues.

CONCLUSIONS

Immunized pigs can be infected with wild-type PRV without being detected by the gE-specific ELISA, which is routinely used to discriminate between infected and vaccinated pigs. The implication for eradication programs is that these pigs might be a source of new outbreaks.

An indirect double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) using baculovirus-expressed antigen for the detection of antibodies to glycoprotein E of pseudorabies virus and comparison of the method with blocking ELISAs

Antibodies in porcine sera against glycoprotein E (gE) of pseudorabies virus (PRV) are usually measured in blocking enzyme-linked immunosorbent assays (ELISAs) with one or two murine monoclonal antibodies (MAbs) directed against gE. Our aim was to develop a confirmation assay which is based on another principle and which is able to detect antibodies directed against most potential binding sites on gE with high specificity. Therefore, we developed an indirect double-antibody sandwich assay (IDAS) using recombinant gE expressed by baculovirus (BacgE960). A fragment of the gE gene consisting of nucleotide positions +60 to +1020 of gE, coding for the major antigenic sites of gE but not the transmembrane region, was cloned behind the signal sequence of PRV gG and the p10 promoter in a baculovirus vector. Immunoblot analysis showed that the expressed protein reacted with MAbs directed against five of the six antigenic sites on gE. Although the conformation of some antigenic sites, notably antigenic sites E and C, was not identical to their natural conformation, the expressed protein bound gE-specific antibodies in porcine sera in Western blots (immunoblots) and ELISAs. For the IDAS, a coating MAb directed against the nonimmunodominant antigenic site A on gE was chosen. A major obstacle in binding ELISAs, such as the IDAS, appeared to be the high nonspecific binding activity observed in porcine sera. As a result, sera could be tested only in relatively high dilutions in the BacgE960 IDAS, in contrast to the testing of sera in blocking ELISAs. The sensitivity and specificity of the newly developed BacgE960 IDAS were evaluated and compared with those of five commercially available blocking ELISAs by using several sets of sera of known PRV disease history. The BacgE960 IDAS assay had a high diagnostic specificity and a moderate sensitivity. The five blocking ELISAs differed remarkably in sensitivity and specificity, thereby illustrating the need for standardization and confirmation. We conclude that the BacgE960 IDAS is a useful and specific additional (confirmatory) test for the detection of antibodies to gE.

Abdominal aortic aneurysm repair in Veterans Affairs medical centers

PURPOSE

This study was performed to define outcomes after abdominal aortic aneurysm (AAA) repair in Veterans Affairs (VA) medical centers during fiscal years 1991 through 1993.

METHODS

With VA patient treatment file data, patients were selected from diagnosis-related groups 110 and 111 and were then classified in a patient management category. In the categories of repair of nonruptured and ruptured AAA, mortality and postoperative complication rates were defined for patients who underwent AAA repair in VA medical centers during the 3-year study period.

RESULTS

Hospital mortality rates were 4.86% (166 of 3419) after repair of nonruptured AAA and 47.0% (126 of 268) after repair of ruptured AAA (p<0.001). Of 292 deaths after AAA repair, 136 (43.2%) followed repair of ruptured AAA, even though ruptured AAA comprised only 7.3% of total AAA surgical volume. AAA repairs were performed at 116 VA medical centers, with 31.8+/-23.1 (range, 1 to 140) procedures performed at each center. Although many lower-volume centers had excellent results, centers that performed >or=32 AAA repairs tended to have lower in-hospital mortality rates after repair of nonruptured AAA than those that performed <or=31 procedures (4.2%+/-3.5% compared with 6.7%+/-7.8%;p<0.05). Poisson regression analysis revealed an inverse relationship between the volume of AAA repairs and individual hospital mortality (p=0.001) and a direct relationship between illness severity and hospital mortality (p=0.008). The proportion of ruptured AAAs treated in a hospital was also directly related to individual hospital mortality rates (p<0.005). Postoperative complications were associated with an increased hospital mortality rate (11.7% with complication compared with 6.5% without; p<0.0001) and length of stay (23.6+/-17.1 days compared with 18.0+/-12.4 days; p<0.0001). In a logistic regression model, increased mortality rates after AAA repair were associated with hospital type (adjusted odds ratio [OR]=0.6), increasing age (OR=1.1), patient management category severity score (OR=2.2), hemorrhage (OR=2.3), myocardial infarction (OR=2.6), disseminated intravascular coagulation (OR=4.7), AAA rupture (OR=6.0), postoperative shock (OR=10.7), cardiopulmonary arrest (OR=15.4), central nervous system complications (OR=16.0) and urologic complications (OR=2.4).

CONCLUSIONS

Mortality rates after AAA repair in VA hospitals were comparable with those previously reported in other large series. Outcomes for veterans with AAA may improve by referring patients eligible for elective repair to VA medical centers with a greater operative volume or to lower-volume centers that have had excellent results.

Circulating natural killer cells but not cytotoxic T lymphocytes are reduced in patients with active relapsing multiple sclerosis and little clinical disability as compared to controls

Triple antibody flow cytometry was used to compare the populations of CD56+ effector cells in the peripheral circulation of 29 patients with relapsing multiple sclerosis (MS) and little disability who were exacerbation-free for over 2 months and 29 healthy control subjects. Populations were characterized by two panels of antibodies (CD8, CD16, CD56 and CD3, CD8, CD56), as well as by size or granularity. In the MS patients, mature natural killer (NK) cells (CD3-CD8-CD56+) of small size and low granularity were significantly reduced compared to normals (P(0.0003). The quantities of other effector cells (cytotoxic T lymphocytes, large granular lymphocytes and monocytes) were not different in MS patients compared to the control subjects. Also, we identified a previously unrecognized population of CD56+ monocytes (CD3-CD14+CD56+) in both the normal control subjects and the MS patients which would have been misclassified as NK cells using one or two antibody cytometry employed in previous studies.

Conservative management of ovarian hyperstimulation syndrome

OBJECTIVE

To evaluate the performance of a conservative treatment protocol for ovarian hyperstimulation syndrome (OHSS) that utilized low-dose dopamine, volume expanders and diuretics.

STUDY DESIGN

Prospective, open trial.

RESULTS

Thirteen patients met the criteria for diagnosis of severe OHSS during the study period. Two of these were in vitro fertilization (IVF) patients who did not undergo transfer and so were excluded from analysis. Of the remaining 11, 10 (91%) were pregnant. The average time for resolution of the OHSS and discharge from the hospital was 6 days (range, 2-11). Compared to levels at admission, there was no significant difference in those of sodium, potassium or creatinine after resolution of the syndrome. Hemoglobin and hematocrit, however, were significantly reduced (P < .03). There were no cases of adult respiratory distress syndrome or thrombosis. No pregnancies were interrupted.

CONCLUSION

Conservative treatment of OHSS is an acceptable form of management. Risky and invasive therapies, such as paracentesis, are not warranted.

National Medical Association Surgical Section position paper on violence prevention. A resolution of trauma surgeons caring for victims of violence

The epidemic of intentional injury continues to be a leading cause of premature death in America. The ravages of violence are particularly devastating within the minority community. With this position paper from the Surgical Section of the National Medical Association (the country's oldest and largest organization of minority physicians), a group of trauma surgeons and surgical intensivists resolve to focus on underused violence prevention opportunities and to extend their spheres of influence beyond the walls of their institutions and emphasize violence prevention activities.

Case report: hypoglycemia secondary to a meningioma

Hypoglycemia secondary to a meningioma that has not metastasized to the liver has not been reported previously. A 41-year-old woman with a spinal cord meningioma first diagnosed 5 years previously with 3 recurrences in the spinal cord resulting in 4 neurosurgical procedures was admitted with a serum glucose of 23 mg/dL. Six months before the current admission, the patient was noted to have an abdominal mass of 10 cm not present on previous computed tomography. Three months later, the mass was 15.2 cm, and on the current admission, had increased to 23 cm and encased both the aorta and inferior vena cava. A needle biopsy of this mass before referral to the authors' hospital with hypoglycemia revealed that it was a meningioma. Evaluation of the etiology of the hypoglycemia, which required continuous intravenous glucose therapy, revealed that circulating insulin, C-peptide (i.e., connecting peptide), insulin-like growth factor-I (i.e., somatomedin-C) and insulin-like growth factor-II were all normal or low. Serum cortisol also was not low. Based on her endocrine evaluation, the hypoglycemia was secondary to the large mass of tumor cells, requiring a large glucose uptake to sustain its growth. After radiation therapy of 3,770 CGy to the meningioma, the patient became euglycemic without glucose supplementation.

Clinical nurse practitioner in a surgical team

The role of a nurse taking on many of the duties of PRHO in a surgical team is described with the responsibilities, relationships and limitations. A nurse can carry out almost all of the elective activity of a PRHO and significantly relieve the pressure of work on others. She cannot completely substitute for PRHOs out of hours. As more consultants are appointed without additional medical members of the team, it is suggested that two consultant teams might be best served by one PRHO working with one Clinical Nurse Practitioner.

A brief history of the use of interferons as treatment of multiple sclerosis

Interferons (IFNs) are a family of glycoproteins that are naturally secreted by certain cells in response to viral infection. The naturally occurring IFNs confer protection on other cells, preventing them from becoming infected, a phenomenon referred to as "virus interference" by Isaacs and Lindenmann in the first description of these proteins. In addition to their antiviral properties, the IFNs also have complex immunomodulatory, antiproliferative, and hormonelike activities, which are not completely understood.

The lesion causing continuous facial myokymia in multiple sclerosis

OBJECTIVE

To attempt to identify the site of the lesion causing continuous facial myokymia (CFM) in multiple sclerosis (MS) through the use of magnetic resonance imaging (MRI).

DESIGN

A case series was employed.

SETTING

The Baird Multiple Sclerosis Center, Millard Fillmore Hospital, and the Neurology Department, Buffalo General Hospital, Buffalo, NY.

PARTICIPANTS AND MEASURES

Twelve patients with MS and CFM were examined by MRI of the brain while the CFM was present. The MRI examinations were also performed before the CFM had developed and after it had ceased in eight of the patients. Another 57 patients with MS who never had CFM but who had similar disabilities to those who did were also examined by MRI.

RESULTS

In 11 of the 12 patients with MS and CFM, the causative lesion was demonstrated to involve the postnuclear, postgenu portion of the facial nerve intraaxially in the dorsolateral pontine tegmentum ipsilateral to the CFM. In the majority of patients who were studied after the CFM had stopped clinically, the lesion was observed to resolve on MRI. Seventeen percent of the patients with MS but without CFM were found to have the typical pontine tegmental lesion.

CONCLUSIONS

Continuous facial myokymia in MS is caused by a pontine tegmental lesion involving the postnuclear, postgenu portion of the facial nerve. The lesion is identified by MRI in approximately 90% of patients with MS who have CFM clinically. The typical MRI lesion may also be found in a minority of patients with MS who do not have CFM clinically.

Glycoprotein gE-negative pseudorabies virus has a reduced capability to infect second- and third-order neurons of the olfactory and trigeminal routes in the porcine central nervous system

We investigated the spread of glycoprotein gE (gE)-negative pseudorabies virus (PRV) and its rescued 'wild-type' strain into and within the central nervous system (CNS) of 3- and 10-week-old pigs. This is the first study that demonstrates PRV invasion of the porcine CNS via the synaptically linked neurons of the olfactory and trigeminal routes and that demonstrates the role of gE in this invasion. After intranasal inoculation with high doses of virus, gE-negative PRV replicated less efficiently in peripheral tissues. The titres of the gE-negative virus in the oropharyngeal mucosa, olfactory epithelium, draining lymph nodes and trigeminal ganglion were approximately 100-fold lower in 3-week-old pigs and 10-fold lower in 10-week-old pigs than titres of the 'wild-type' virus. In contrast to the 'wild-type' virus, titres of the gE-negative virus were very low or undetectable in the olfactory bulb, brain stem and other tissues of the CNS. Viral antigen of rescued 'wild-type' PRV and of gE-negative PRV was detected immunohistochemically in the olfactory epithelium and in neurons of the trigeminal ganglion, and also in the olfactory and trigeminal axons leading towards the CNS. But, in contrast to 'wild-type' virus, no viral antigen of the gE-negative virus was detected in second- or third-order neurons in the olfactory bulb or in the brain stem. We conclude that gE-negative PRV can infect first-order neurons of the olfactory and trigeminal routes and is able to spread via their axons towards the CNS. Yet, gE-negative PRV has a greatly reduced capacity to infect second- or third-order neurons. Finally, we report lateral spread of 'wild-type' PRV in the trigeminal ganglion, i.e. nonsynaptic transport from neuron to neuron. Possible mechanisms that could explain the reduced levels of the gE-negative virus in the CNS are discussed.

Epitope-specific antibody response against glycoprotein E of pseudorabies virus

In this study we investigated the epitope-specific antibody response against glycoprotein E (gE) of pseudorabies virus. Epitope-specific antibody responses were investigated by enzyme-linked immunoperoxidase monolayer assays. In a vaccinated crossbred pig population, most pigs responded to antigenic domain E and to a lesser degree to antigenic domains C and D. Only few pigs responded to antigenic domains F, A, and B. Using vaccinated pigs, we investigated the influence of two different pseudorabies virus strains and the genetic background of the host on the epitope-specific antibody response. More pigs infected with the virulent NIA-3 strain had a detectable antibody response against antigenic domains C, F and A than did pigs infected with the mildly virulent Sterksel strain (P < or = 0.05; Fisher's exact test). No differences in the epitope-specific antibody responses of two genetically different pig breeding lines were observed (P > or = 0.1; Fisher's exact test). In both breeding lines the incidence of the epitope-specific antibody response was comparable to that in the crossbred pig population. In addition, we studied the epitope-specific antibody responses were strikingly different and indicated that genetic background influenced the epitope-specific antibody response. Of the serum samples of mice with C57BL and a BALB background, 40 and 17% respectively, were positive in the one of the epitope-specific immunoassays. In contrast to pigs, mice responded predominantly to antigenic domain D and to a lesser degree to antigenic domains E and B. Only few mice had a detectable antibody response against antigenic domains C and A, and none had a detectable antibody response against antigenic domain F.

Glycoprotein E of pseudorabies virus and homologous proteins in other alphaherpesvirinae

This paper reviews biological properties of glycoprotein E (gE) of pseudorabies virus (Aujeszky's disease virus) and homologous proteins in other alphaherpesvirinae. It focuses on the gene encoding gE, conserved regions in the gE protein and its homologs, the complex of gE and gI, biological functions of gE in vitro and in vivo, the role of gE in latency and the role of gE in the induction of humoral and cellular immune responses. Special emphasis is placed on the use of gE as a marker protein in the control and eradication of pseudorabies virus.

Accuracy of fatal motorcycle-injury reporting on death certificates

This study identifies differences in motorcycle injury fatality statistics gathered from different sources. Police Accidents Reports (PARs), identifying fatal motorcycle injuries occurring in Connecticut during 1987 were matched with state death certificates. Matched death certificates were analyzed in three major areas: content, coding, and motorcycle fatality reporting. Death certificates underreported motorcycle fatalities by 38% compared to PARs. Forty percent of death certificates were missing some or all of the required information: 7 did not include the word motorcycle, 18 did not contain acceptable ICD-9 terminology for a motorcyclist, and 17 did not describe how the injury occurred. Forty-one percent of death certificates contained external cause of injury code (E-code) errors. Incomplete information on death certificates was responsible for 52% of inaccurate reporting and E-code errors for 48%. The accuracy of fatal motorcycle injury cause of death reporting on death certificates could be improved by better physician training and rapid implementation of both the computerized death certificate coding systems and upcoming ICD-10 classification system.

Abnormalities of fibrillin in acquired cutis laxa

BACKGROUND

Degeneration of elastic tissue in acquired cutis laxa has been previously described, but microfibrils have not been adequately studied.

OBJECTIVE

We determined whether the microfibrillar component of elastic tissue is affected in skin of a patient with acquired cutis laxa.

METHODS

Lesional skin was examined with indirect immunofluorescence and immunoelectron microscopy with antibodies to fibrillin.

RESULTS

Indirect immunofluorescence showed a reduction in the distribution of fibrillin in the papillary dermis, where there was loss of the usual pattern of microfibrils perpendicular to the epidermis. Immunoelectron microscopy showed a typical distribution of elastic microfibrils around elastin of normal skin. In skin affected by cutis laxa microfibrils appeared morphologically normal but appeared less frequently in selected sites.

CONCLUSION

The microfibrillar component of elastic fibers was reduced in the papillary dermis of this patient with acquired cutis laxa.

Advances in specific therapy for multiple sclerosis

During the past year, two new agents have been demonstrated to be of value in multiple sclerosis. The first agent, a form of recombinant interferon beta (Betaseron; Berlex Labs, Cedar Knolls, NJ), is effective in reducing relapses and also prevent accumulation of brain lesions over time, but has no demonstrated effect on the accumulation of disability over time. The second agent, methylprednisolone (Solumedrol; The Upjohn Co., Kalamozoo, MI), administered in megadose pulses over several days and followed by an oral prednisone taper, reduces the conversion rate of patients with optic neuritis to multiple sclerosis by approximately 50% over 2 years compared with placebo or oral prednisone alone. The mechanisms by which these agents exert their benefits are incompletely understood, but both have complex, relatively widespread effects on the immune systems. The demonstration of efficacy for both of these agents represent landmarks in the search for an effective treatment for multiple sclerosis; both agents seem to provide prophylaxis against future relapses, and methylprednisolone seems to delay the development of the disease. Their introduction into the clinical environment will undoubtedly have a profound effect on the day-to-day care of multiple sclerosis patients as well as the designs of future basic and clinical research. Other new therapies that have substantial potential for benefit in multiple sclerosis but require further definitive study include intramuscular copolymer 1 for relapsing disease and low-dose oral methotrexate and booster doses of intravenous cyclophosphamide for chronic progressive disease.

Spontaneous palpebromandibular synkinesia: a localizing clinical sign

In the classical corneomandibular reflex (CMR), corneal stimulation elicits a bilateral eyelid blink and a brisk anterolateral jaw movement. We here describe 14 patients with a spontaneous palpebromandibular (eyelid-jaw) synkinesia (SPMS) in whom jaw movements, similar to those in CMR, regularly accompanied spontaneous eye blinks without an external corneal stimulus. Eleven of the patients with SPMS also had CMRs on corneal stimulation. Four patients had clinical and imaging evidence of brainstem lesions above the mid-pons, 5 patients had autopsy or imaging evidence of both bilateral cerebral and upper brainstem lesions, and 5 patients had clinical or imaging evidence of bilateral cerebral dysfunction. Topical corneal anesthesia administered to patients who had both CMR and SPMS blocked the CMR but had no effect on the SPMS. In patients with both SPMS and CMR, measurements of latency from onset of orbicularis oculi electromyographic activity to onset of lateral pterygoid EMG activity, and mandibular kinesiography of jaw velocity and direction showed that the eyelid-jaw synkinesias of CMR and SPMS had similar characteristics. We conclude that SPMS is pathophysiologically the same as the eyelid-jaw synkinesia of CMR and both synkinesias originate centrally, probably in the pons. In CMR, the jaw movement is primarily related to the blink rather than the corneal stimulus, but corneal stimulation may be necessary to overcome a higher threshold for expression of the synkinesia than in patients with SPMS. Like CMR, SPMS emerges in patients with upper brainstem or bilateral cerebral lesions and SPMS may therefore be a useful localizing clinical sign.

Deleting two amino acids in glycoprotein gI of pseudorabies virus decreases virulence and neurotropism for pigs, but does not affect immunogenicity

The virulence, pathogenicity and immunogenicity of two pseudorabies virus (PRV) variants were investigated in 3-week-old pigs that had been intranasally infected. Variant M303 (delta 125,126) lacked amino acids valine (125) and cysteine(126) in an immunodominant antigenic region of glycoprotein I (gI) containing two discontinuous antigenic domains, whereas M304 (delta 59,60) lacked amino acids glycine(59) and aspartic acid(60) in a continuous antigenic domain. M303 (delta 125,126) was not virulent for pigs, but M304 (delta 59,60) was as virulent as wild-type PRV: all pigs died within 8 days of infection. Both gI mutant viruses replicated in the oropharyngeal mucosa, although M304 (delta 59,60) replicated to higher virus titres than M303 (delta 125,126), and virus was recovered from various tissues. However, in contrast to M304 (delta 59,60), M303 (delta 125,126) was not recovered from any central nervous system (CNS) tissues examined. Thus, the tendency of PRV to locate in the CNS was markedly reduced by deleting amino acids valine(125) and cysteine(126) of gI. Pigs immunized with M303 were completely protected against challenge infection; no clinical signs of disease were detected, no virus was shed, and no secondary antibody response was detected. Thus, deleting amino acids valine(125) and cysteine(126) in gI decreases virulence and neurotropism and does not affect immunogenicity.