Virtual versus usual in-office care for multiple sclerosis: The VIRTUAL-MS multi-site randomized clinical trial study protocol

BACKGROUND

Multiple sclerosis (MS) affects nearly 1 million people and is estimated to cost $85.4 billion in the United States annually. People with MS have significant barriers to receiving care and telemedicine could substantially improve access to specialized, comprehensive care. In cross-sectional analyses, telemedicine has been shown to be feasible, have high patient and clinician satisfaction, reduce patient costs and burden, and enable a reasonable assessment of disability. However, no studies exist evaluating the longitudinal impact of telemedicine care for MS. Here we describe the study protocol for VIRtual versus UsuAL In-office care for Multiple Sclerosis (VIRTUAL-MS). The main objective of the study is to evaluate the impact of telemedicine for MS care on: patient clinical outcomes, economic costs, patient, and clinician experience.

METHODS

This two-site randomized clinical trial will enroll 120 adults with a recent diagnosis of MS and randomize 1:1 to receive in-clinic vs. telemedicine care for 24 months. The primary outcome of the study is worsening in any one of the four Multiple Sclerosis Functional Composite 4 (MSFC4) measures at 24 months. Other study outcomes include patient and clinician satisfaction, major healthcare costs, Expanded Disability Status Scale, treatment adherence, and digital outcomes.

CONCLUSION

The results of this study will directly address the key gaps in knowledge about longitudinal telemedicine-enabled care in an MS population. It will inform clinical care implementation as well as design of trials in MS and other chronic conditions.

TRIAL REGISTRATION

NCT05660187.

Predictors for the development of neurological immune-related adverse events of immune checkpoint inhibitors and impact on mortality

BACKGROUND AND PURPOSE

Little is known about risk factors for developing neurological immunological adverse events (neuro-irAEs) from immune checkpoint inhibitors (ICIs). We report the incidence, predictors for development, impact on mortality of neuro-irAEs, and impact of ICIs on pre-existing neurological conditions in a large clinical cohort.

METHODS

Patients who received ICIs between January 2011 and December 2018 were identified from a tertiary cancer center registry. Descriptive statistics were used to summarize patient, cancer, and treatment data. Odds ratios from univariable and multivariable logistic regression models were calculated to identify potential predictors for developing a neuro-irAE. Impact of neuro-irAEs on overall survival was estimated by Kaplan-Meier and Cox proportional hazard models.

RESULTS

Overall frequency of neurological irAEs was 2.3%. Peripheral nervous system complications were most frequent (53.6%). Melanoma, younger age, prior chemotherapy, prior resection, CTLA-4 ICIs exposure, and combination PD-1 and CTLA-4 ICIs exposure had significantly higher odds for developing a neuro-irAE (p < 0.05) in univariate but not multivariate models. Those with a neuro-irAE were less likely to die at 3 years compared to those without a neuro-irAE (69% vs. 55%, p = 0.004) in univariate but not multivariate model. Flare of pre-existing neurological condition after exposure to ICIs was present (15.4%, 2 of 13 patients) but manageable. One patient was rechallenged with ICIs without recurrent flare.

CONCLUSIONS

Neuro-irAEs are not associated with increase in overall mortality. Potential predictors for the development of neuro-irAEs are younger age, melanoma, prior chemotherapy and resection, CTLA-4, or combination ICIs exposure.

Predictors for the Development of Neurological Immune-Related Adverse Events of Immune Checkpoint Inhibitors and Impact on Mortality

Objective

To report the incidence, predictors for development, impact on mortality, and impact on pre-existing neurological conditions of neurological immune-related adverse events (irAEs) in a large clinical cohort.

Background

Immune checkpoint inhibitors (ICI) are associated with irAEs. Although neurological complications have been described, little is known about risk factors for their development and their impact on mortality. The impact of ICIs on pre-existing neurological conditions is also not well understood.

Design/Methods

Patients who received ICI between January 2013 and December 2018 were identified using a tertiary cancer center registry. Patient demographics, cancer characteristics, treatment type, and concurrent oncologic therapy were summarized using descriptive statistics. Patients with neuro-irAE were compared to those without neuro-irAE during the study timeframe. Odds ratios from univariable and penalized multivariable logistic regression models were calculated to identify potential predictors for developing a neuro-irAE. The impact of a neuro-irAE on overall survival was estimated by Kaplan-Meier and multivariable Cox proportional-hazard models.

Results

Overall frequency of neurological irAEs was 2.3% (28/1228). Peripheral nervous system complications such as myasthenia gravis, myositis, and neuropathies were the most frequent (53.6%). Melanoma, younger age, prior chemotherapy, prior resection, CTLA-4 ICI exposure, and combination ICI exposure had significantly higher odds for developing a neuro-irAE (p <0.05), but these findings were not statistically significant in the multivariable models. Those with a neuro-irAE had greater survival at 3 years compared to those without a neuro-irAE (69% vs 55%, p = 0.004), but after adjusting for patient and cancer characteristics, this effect was no longer statistically significant. Relapse rate of pre-existing neurological condition after exposure to ICI was 15.4% (2/13).

Conclusions

Neuro-irAEs are rare and are not associated with an increase in mortality. Potential predictors for the development of neuro irAEs are younger age, melanoma, prior chemotherapy and resection, CTLA-4, or combination ICI exposure. Relapse of a pre-existing neurological condition was uncommon.

Clinical and Research Applications of the Electronic Medical Record in Multiple Sclerosis: A Narrative Review of Current Uses and Future Applications

BACKGROUND

The electronic medical record (EMR) has revolutionized health care workflow and delivery. It has evolved from a clinical adjunct to a multifaceted tool, with uses relevant to patient care and research.

METHODS

A MEDLINE literature review was conducted to identify data regarding the use of EMR for multiple sclerosis (MS) clinical care and research.

RESULTS

Of 282 relevant articles identified, 29 were included. A variety of EMR integrated platforms with features specific to MS have been designed, with options for documenting disease course, disability status, and treatment. Research efforts have focused on early diagnosis identification, relapse prediction, and surrogates for disability status.

CONCLUSIONS

The available platforms and associated research support the utility of harnessing EMR for MS care. The adoption of a core set of discrete EMR elements should be considered to support future research efforts and the ability to harmonize data across institutions.

Providing Person-Centered Care via Telemedicine in the Era of COVID-19 in Multiple Sclerosis

The coronavirus disease 2019 (COVID-19) pandemic has catalyzed the rapid adoption of telemedicine which encompasses synchronous and asynchronous interactions between patients and providers. In order to facilitate this rapid deployment, there has been numerous regulatory changes to ensure caregivers can effectively communicate with patients during this time. We illustrate a model where people, processes, and technology work together to address the comprehensive needs of multiple sclerosis (MS) patients. We provide a template for how multidisciplinary, academic practices can implement a rapid shift to virtual management during the pandemic using existing infrastructure that can be widely adopted to care for patients with chronic diseases. Telemedicine was incorporated into our entire practice, which encompasses neurology, rehabilitation, advanced practice providers, fellows, social work, and behavioral medicine. Our patient satisfaction results remained stable across almost all domains when compared to survey results from our typical, in-office visits. Our experience demonstrates telemedicine’s transformative potential in successfully managing a multidisciplinary MS clinic during the time of a pandemic and outlines a potential path for other practices to follow.

Implementation and Patient Experience of Outpatient Teleneurology

Background: Teleneurology has been well described for acute stroke, but outpatient use has been limited. At home, virtual visits have the potential to improve access to neurological care. Introduction: This study reports on the use of a personal device videoconferencing platform for outpatient neurologic follow-up visits. Materials and Methods: This is a cross-sectional study that identified all virtual neurologic follow-up visits completed by patients ≥18 years at a single institution over 4 years. Virtual visits were conducted by personal smartphone or computer via videoconferencing with a provider. Patients were asked to rate their overall experience with the visit and provider (five-point scale). Travel distance from the institution was calculated using patient's home addresses. Results: Three thousand nine hundred thirteen patients completed 5,581 virtual visits during the study (mean age 49.4 ± 17.0 years, 58.7% female). Number of virtual visits increased from 30 in year 1 to 4,468 in year 4. Virtual visits were completed in all outpatient neurologic subspecialties. A total of 30.1% of patients were local (<50 miles), 25.9% were near regional (50-150 miles), 21.7% were far regional (151-270 miles), and 22.2% were remote (>270 miles). A distance of 1,327,128 miles of travel was prevented across the 5,581 visits. On average, patients rated their overall virtual visit experience 4.7/5 ± 0.89 and rated their provider 4.9/5 ± 0.48. Discussion: Virtual visits prevented a substantial amount of travel and resulted in high patient satisfaction. The sizable proportion of local patients may indicate that teleneurology provides important access for reasons beyond travel distance. Conclusion: This study demonstrates the feasibility of implementing outpatient teleneurology services.

Multiple Sclerosis Performance Test: validation of self-administered neuroperformance modules

BACKGROUND AND PURPOSE

The purpose was to determine the test-retest reliability, practice effects, convergent validity and sensitivity to multiple sclerosis (MS) disability of neuroperformance subtests from the patient self-administered Multiple Sclerosis Performance Test (MSPT) designed to assess low contrast vision (Contrast Sensitivity Test, CST), upper extremity motor function (Manual Dexterity Test, MDT) and lower extremity motor function (Walking Speed Test, WST) and to introduce the concept of regression-based norms to aid clinical interpretation of performance scores using the MSPT cognition test (Processing Speed Test, PST) as an example.

METHODS

Substudy 1 assessed test-retest reliability, practice effects and convergent validity of the CST, MDT and WST in 30 MS patients and 30 healthy controls. Substudy 2 examined sensitivity to MS disability in over 600 MS patients as part of their routine clinic assessment. Substudy 3 compared performance on the PST in research volunteers and clinical samples.

RESULTS

The CST, MDT and WST were shown to be reliable, valid and sensitive to MS outcomes. Performance was comparable to technician-administered testing. PST performance was poorer in the clinical sample compared with the research volunteer sample.

CONCLUSIONS

The self-administered MSPT neuroperformance modules produce reliable, objective metrics that can be used in clinical practice and support outcomes research. Published studies which require patient voluntary consent may underestimate the rate of cognitive dysfunction observed in a clinical setting.

Bringing the HEET: The Argument for High-Efficacy Early Treatment for Pediatric-Onset Multiple Sclerosis

Pediatric-onset multiple sclerosis (POMS) is rarer than adult-onset disease, and represents a different diagnostic and treatment challenge to clinicians. We review POMS clinical and radiographic presentations, and explore important differences between POMS and adult-onset MS natural histories and long-term outcomes. Despite having more active disease, current treatment guidelines for patients with POMS endorse the off-label use of lower-efficacy disease-modifying therapies (DMTs) as first line. We review the available MS DMTs, their evidence for use in POMS, and the contrasting treatment strategies of high-efficacy early treatment and escalation therapy. We introduce a new treatment approach, the "high-efficacy early treatment", or HEET strategy, based on using directly observed, high-efficacy intravenously infused DMTs as first-line therapies. Like other proposed POMS treatment strategies, HEET will need to be prospectively studied, and all treatment decisions should be determined by an experienced neurologist, the patient, and his/her parents.

Leucine-Rich Glioma Inactivated-1 and Voltage-Gated Potassium Channel Autoimmune Encephalitis Associated with Ischemic Stroke: A Case Report

Autoimmune encephalitis is associated with a wide variety of antibodies and clinical presentations. Voltage-gated potassium channel (VGKC) antibodies are a cause of autoimmune non-paraneoplastic encephalitis characterized by memory impairment, psychiatric symptoms, and seizures. We present a case of VGKC encephalitis likely preceding an ischemic stroke. Reports of autoimmune encephalitis associated with ischemic stroke are rare. Several hypotheses linking these two disease processes are proposed.

A Pediatric Patient with Refractory Seizures and a Mesial Temporal Lobe Lesion

A 12-year-old adolescent presented with refractory seizures and was found to have a mesial temporal lobe lesion. The patient underwent biopsy and was diagnosed with an arteriovenous malformation. Supratentorial lesions in the pediatric population can have a large variety of underlying etiologies, which can be challenging to differentiate on neuroimaging. In this report, we discuss the key features on MRI of several neoplastic, vascular, and infectious processes that can aide in the diagnosis.

Older adults exhibit more intracortical inhibition and less intracortical facilitation than young adults

BACKGROUND

Aging results in decreased neuromuscular function, which is likely associated with neurologic alterations. At present little is known regarding age-related changes in intracortical properties.

METHODS

In this study we used transcranial magnetic stimulation (TMS) to measure intracortical facilitation (ICF), short- and long-interval intracortical inhibition (SICI and LICI), motor evoked potential amplitude, and silent period duration in young and older adults (21.4+/-0.8years and 70.9+/-1.8years). These variables were assessed from the flexor carpi radialis muscle of the non-dominant arm under resting conditions, and during a submaximal contraction (intensity 15% maximum strength).

RESULTS

Older adults exhibited increased SICI and LICI in comparison to young adults (SICI: 29.0+/-9.2% vs. 46.2+/-4.8% of unconditioned pulse; LICI: 6.5+/-1.7% vs. 15.8+/-3.3% of unconditioned pulse; P=0.04), and less ICF under resting conditions (74.6+/-8.7% vs. 104.9+/-6.9% of unconditioned pulse; P=0.02). These age-related differences disappeared during contraction, although the older adults did exhibit a longer silent period during contraction (112.5+/-6.5 vs. 84.0+/-3.9ms; P<0.01).

CONCLUSIONS

Collectively, these findings suggest increased GABA mediated intracortical inhibition with age.

Identification of stathmin as a novel substrate for p38 delta

p38 mitogen-activated protein kinases (MAPK) are a family of kinases that are activated by cellular stresses and inflammatory cytokines. Although there are many similarities shared by the isoforms of p38 (alpha, beta, gamma, and delta), p38 delta differs from the others in some respects such as inhibitor sensitivity and substrate specificity. Utilizing in a solution kinase assay, we identified a novel p38 delta substrate as stathmin. Stathmin is a cytoplasmic protein that was previously reported to be a substrate of several intracellular signaling kinases and has recently been linked to regulation of microtubule dynamics. p38 delta has significantly higher in vitro phosphorylating activity against stathmin than other p38 isoforms or related MAPKs. In transient expression studies, we found that in addition to different stimuli osmotic stress activates p38 delta to phosphorylate stathmin. The sites of phosphorylation were mapped to Ser-25 and Ser-38, both in vitro and in cells.

Use of monetary reinforcement to reduce the cigarette smoking of persons with schizophrenia: a feasibility study

The feasibility of using monetary reinforcement to promote abstinence from substance use in adult individuals with schizophrenia was addressed. Cigarette smoking was studied as an exemplar of drug use in 11 individuals with schizophrenia by use of a within-subject experimental design. The study duration was 3 weeks, with weeks 1 and 3 serving as baseline conditions and week 2 serving as the intervention condition; in the latter, patients could earn money by abstaining from cigarette smoking. Abstinence was significantly greater during the intervention condition than during the baseline conditions. These results illustrate the potential sensitivity of drug use in this population to reinforcement contingencies, suggesting that contingency-management interventions are a feasible option for treating the substance abuse of individuals with schizophrenia.

Satisfaction with midwife-managed care in different time periods: a randomised controlled trial of 1299 women

OBJECTIVE

To compare women's satisfaction with midwife-managed care with 'shared care' over three different time periods.

DESIGN

Randomised controlled trial.

SETTING

Glasgow Royal Maternity Hospital, Glasgow, UK.

PARTICIPANTS

1299 women experiencing normal pregnancy (consent rate: 82%). Six hundred and forty-eight women were randomised to midwife-managed care and 651 to 'shared care'.

METHODS

Three self-report questionnaires were sent to women's homes. The questionnaires examined: satisfaction with antenatal care at 34-35 weeks' gestation, and satisfaction with intrapartum, hospital- and home-based postnatal care at seven weeks postnatally. The third questionnaire reviewed satisfaction with intrapartum care seven months after delivery.

FINDINGS

Women in both groups were satisfied. However, women in the midwife-managed group were more highly satisfied in relation to the dimensions examined: relationships with staff, information transfer, choices and decisions, and social support. The differences between the two groups were evident for all time periods (i.e. antenatal, intrapartum and postnatal periods) and were sustained at seven-month follow-up. This is illustrated in the mean scores for relationships with staff, as measured at 34-35 weeks' gestation (possible range -2; very negative attitudes to 2; very positive attitudes). Women in the midwife-managed group scored a mean of 1.22 compared to 0.74 for the 'shared care' group (mean diff: 0.48; 95% CI: 0.42 to 0.55). While women in both groups were more likely to make positive rather than negative comments in open-ended questions, the midwife-managed group were more likely to make positive comments whereas the 'shared care' group were more likely to make negative comments.

CONCLUSION

Midwife-managed care for healthy pregnant women which is integrated into existing services improves satisfaction with antenatal, intrapartum and postnatal care.

A randomized trial of three iron dextran infusion methods for anemia in EPO-treated dialysis patients

Forty-three hemodialysis patients receiving recombinant erythropoietin (rHuEPO, epoietin alpha) were randomized to receive intravenous iron dextran as a total-dose infusion, 500-mg infusion to total dose, or 100-mg bolus to total dose, in each case during the dialysis procedure. The dose of iron dextran was calculated from the patient's existing hemoglobin to achieve a desired hemoglobin. Patients were eligible to receive intravenous iron dextran if they had a serum ferritin of < or = 100 ng/mL or a serum ferritin of 100 to 200 ng/mL, along with a transferrin saturation of < or = 19%. Patients were excluded if they had prior therapy with iron dextran, aluminum intoxication, or transfusion during the study. The time to the maximum hemoglobin, acute adverse reactions, and delayed adverse reactions were analyzed statistically, and no differences were seen in any of the three groups. Total-dose intravenous iron dextran infusion is safe, convenient, less expensive, and as efficacious as divided-dose infusions.

Kinase suppressor of Ras is ceramide-activated protein kinase

A proline-directed serine/threonine ceramide-activated protein (CAP) kinase mediates transmembrane signaling through the sphingomyelin pathway. CAP kinase reportedly initiates proinflammatory TNF alpha action by phosphorylating and activating Raf-1. The present studies delineate kinase suppressor of Ras (KSR), identified genetically in Caenorhabditis elegans and Drosophila, as CAP kinase. Mouse KSR, like CAP kinase, renatures and autophosphorylates as a 100-kDa membrane-bound polypeptide. KSR overexpression constitutively activates Raf-1. TNF alpha or ceramide analogs markedly enhance KSR autophosphorylation and its ability to complex with, phosphorylate, and activate Raf-1. In vitro, low nanomolar concentrations of natural ceramide stimulate KSR to autophosphorylate, and transactivate Raf-1. Other lipid second messengers were ineffective. Moreover, Thr269 the Raf-1 site phosphorylated by CAP kinase, is also recognized by KSR. Thus, by previously established criteria, KSR appears to be CAP kinase.

Randomised, controlled trial of efficacy of midwife-managed care

BACKGROUND

Midwife-managed programmes of care are being widely implemented although there has been little investigation of their efficacy. We have compared midwife-managed care with shared care (ie, care divided among midwives, hospital doctors, and general practitioners) in terms of clinical efficacy and women's satisfaction.

METHODS

We carried out a randomised controlled trial of 1299 pregnant women who had no adverse characteristics at booking (consent rate 81.9%). 648 women were assigned midwife-managed care and 651 shared care. The research hypothesis was that compared with shared care, midwife-managed care would produce fewer interventions, similar (or more favourable) outcomes, similar complications, and greater satisfaction with care. Data were collected by retrospective review of case records and self-report questionnaires. Analysis was by intention to treat.

FINDINGS

Interventions were similar in the two groups or lower with midwife-managed care. For example, women in the midwife-managed group were less likely than women in shared care to have induction of labour (146 [23.9%] vs 199 [33.3%]; 95% CI for difference 4.4-14.5). Women in the midwife-managed group were more likely to have an intact perineum and less likely to have had an episiotomy (p = 0.02), with no significant difference in perineal tears. Complication rates were similar. Overall, 32.8% of women were permanently transferred from midwife-managed care (28.7% for clinical reasons, 3.7% for non-clinical reasons). Women in both groups reported satisfaction with their care but the midwife-managed group were significantly more satisfied with their antenatal (difference in mean scores 0.48 [95% CI 0.41-0.55]), intrapartum (0.28 [0.18-0.37]), hospital-based postnatal care (0.57 [0.45-0.70]), and home-based postnatal care (0.33 [0.25-0.42]).

INTERPRETATION

We conclude that midwife-managed care for healthy women, integrated within existing services, is clinically effective and enhances women's satisfaction with maternity care.

Changes in midwives' attitudes to their professional role following the implementation of the midwifery development unit

OBJECTIVE

to examine changes in midwives' attitudes to their professional role following the implementation of the midwifery development unit (MDU).

DESIGN

prospective cohort study.

SETTING

the MDU is based at a major teaching hospital in Glasgow, UK. The MDU midwives provide care via a new self-rostering system which is intended to improve continuity of care. Midwives aim to provide total care for each woman from the antenatal period through delivery and the postnatal period.

PARTICIPANTS

21 midwives who joined the MDU were compared with a group of 64 midwives at the hospital who were also eligible and who continued in their usual pattern of work (non-MDU midwives).

MEASUREMENTS

an audit questionnaire was distributed to MDU and non-MDU midwives prior to the implementation of the unit and about 15 months afterwards. In addition, the MDU midwives were sent the questionnaire every three months. Extra questions were added at each time period in order to identify specific problems. This information was then fed back to the midwifery management team to aid in the planning and implementation of the care programme.

FINDINGS

the MDU midwives experienced a significant positive change in attitudes; no significant change was evident for the non-MDU group. There was no evidence of increased stress in the MDU midwives. In general, both groups of midwives had positive attitudes towards the unit and felt that MDU-style care had a role to play in the future provision of maternity care. A number of areas of concern were also highlighted, such as the system of liaison with colleagues.

CONCLUSIONS

innovative models of midwifery care such as an MDU can have a positive impact on midwives' attitudes towards their professional role.

IMPLICATIONS FOR PRACTICE

if change is managed in a systematic manner which involves the midwives, it may be possible to increase midwives' professional satisfaction, while at the same time minimising any negative effects such as increased stress.

Comparison of various methods for the enumeration of blood cells in urine

This study compared the use of conventional urine microscopy, the KOVA system, Neubauer hemacytometry, and the Yellow IRIS for the determination of white blood cell (WBC) and red blood cell (RBC) counts in urine samples. Both KOVA WBC and RBC counts correlated better with the IRIS counts than with conventional microscopy. KOVA WBC counts correlated with Neubauer hemacytometry to the same degree as they did with IRIS WBC counts. The RBC count correlation was fairly similar between KOVA, hemacytometry, and the conventional method. It was concluded that the KOVA system is a suitable replacement for conventional urine microscopy.

Alteration in folding efficiency and conformation of recombinant human tumor necrosis factor-alpha by replacing cysteines 69 and 101 with aspartic acid 69 and arginine 101

An analog of human tumor necrosis factor-alpha (TNF-alpha) was created involving the replacement of Cys69 with Asp and Cys101 with Arg. The solution structure and behavior of this analog were compared with the native protein. The analog exhibited a greatly decreased folding efficiency following dilution from urea, but essentially identical circular dichroic spectra in both the folded and unfolded states. The Stokes radius of the native and analog TNF-alpha in the folded state were identical, with the analog exhibiting a slight broadening of the eluting peak. The fluorescence emission spectrum of the native protein exhibits a plateau from 320 to 328 nm, while the spectrum of the analog consisted of a single peak with a maximum at 335 nm. The analog also had a 1.4-fold increase in the fluorescence intensity. Limited proteolysis of the analog resulted in only one of the two peptides seen following digestion of the native protein, and this product was less stable than the equivalent native protein fragment. The analog exhibited a 10-fold lower cytolytic activity than the native protein. These results demonstrated that the disulfide bond is not necessary for folding and activity, but are consistent with the analog having a looser, more flexible structure in solution than the native TNF-alpha.

Effect of amino-terminal processing by Staphylococcus aureus V-8 protease on activity and structure of recombinant human interferon-gamma

Treatment of recombinant human interferon-gamma (rHuIFN-gamma) with Staphylococcus aureus V-8 protease generated a transiently stable species that lacks 10 amino-terminal residues. This protein showed distinct secondary and higher-order structures with an alpha-helical content of 31%, suggesting that the secondary and tertiary structure largely remain upon removal of 10 amino-terminal residues. The antiviral activity was abolished, or greatly reduced, for this species relative to the intact protein. These results suggest an important role for the amino-terminal portion in the activity of human interferon-gamma. Since the digested protein is difficult to refold from the acid-denatured state, it was concluded that, although not essential for maintaining the core structure of the protein, the amino-terminal portion is critical for refolding the protein from acid.

Colostral transfer of Clostridium perfringens type C beta antitoxin in swine

Nine bred gilts were vaccinated with 2 doses of a Clostridium perfringens type C toxoid at a 5-week interval. Time of vaccination during gestation differed among the gilts. Clostridium perfringens beta antitoxin in colostral samples and in serum samples was titrated in mice. Blood was collected from 2 to 5 neonatal pigs from each dam (total = 32 pigs) when the pigs were 36 to 48 hours old. Antitoxin titers in colostrum were 123 to 4.5 IU/ml, indicating considerable variation in individual responses of the gilts to toxoid. Serum titers of neonatal pigs reflected colostrum titers of their dams. This colostrum-to-serum titer correlation was essentially a straight-line fit by least-squares linear regression analysis, establishing a direct proportional relationship between colostrum titers and serum titers of neonatal pigs. In the dams, a correlation was not found between colostral titers and serum titers of blood samples collected 2 weeks after collection of colostrum.