COMMUNITY CENTERED APPROACHES TO INCREASE PARTICIPATION OF AFRICAN AMERICANS IN BRAIN HEALTH AND ADRD RESEARCH

African Americans/Blacks continue to be underrepresented as participants in Alzheimer’s Disease and related dementia (ADRD) and brain research. Numerous challenges such as lack of information about the Alzheimer’s Disease and related dementia (ADRD), socioeconomic barriers, historical and systemic racism, and distrust of research goals and processes persist in research participation. Research approaches tend to be more recruitment oriented rather than partnership driven that do not address these challenges. As a result, community engagement approaches are increasingly being recognized as a means of building trust and creating new pathways for participation in ADRD studies. This poster focuses on the preliminary work of the Collaborative on Aging Research and Engagement (CARE) --- a community academic partnership comprising the CARE Advisory Team (a community action team of 10 African American leaders), Alzheimer’s Association, the Alzheimer’s Association Greater Indiana Chapter, IU Schools of Nursing, Public Health, and Informatics, Computer Science, and Engineering, and the Indiana Alzheimer’s Disease Research Center. The goal of the partnership is to facilitate active engagement of African Americans aged 45 years and older in research opportunities taking place in in Central and Northwest Indiana. Experiences and perspectives shared at the CARE Advisory Team meetings as well as memos from the researcher staff generated five lessons learned in building relationship oriented, as opposed to recruitment driven, processes. These lessons will be used to develop a community engagement framework focused on the integration of culturally relevant outreach practices in promoting ADRD research opportunities in African American/Black communities.

Priority allocation of pandemic influenza vaccines in Australia - Recommendations of 3 community juries

BACKGROUND

Pandemic planning has historically been oriented to respond to an influenza virus, with vaccination strategy being a key focus. As the current COVID-19 pandemic plays out, the Australian government is closely monitoring progress towards development of SARS-CoV2 vaccines as a definitive intervention. However, as in any pandemic, initial supply will likely be exceeded by demand due to limited manufacturing output.

METHODS

We convened community juries in three Australian locations in 2019 to assess public acceptability and perceived legitimacy of influenza pandemic vaccination distribution strategies. Preparatory work included literature reviews on pandemic vaccine allocation strategies and on vaccine allocation ethics, and simulation modelling studies. We assumed vaccine would be provided to predefined priority groups. Jurors were then asked to recommend one of two strategies for distributing remaining early doses of vaccine: directly vaccinate people at higher risk of adverse outcomes from influenza; or indirectly protect the general population by vaccinating primary school students, who are most likely to spread infection.

RESULTS

Thirty-four participants of diverse backgrounds and ages were recruited through random digit dialling and topic-blinded social media advertising. Juries heard evidence and arguments supporting different vaccine distribution strategies, and questioned expert presenters. All three community juries supported prioritising school children for influenza vaccination (aiming for indirect protection), one by 10-2 majority and two by consensus. Justifications included that indirect protection benefits more people and is likely to be more publicly acceptable.

CONCLUSIONS

In the context of an influenza pandemic, informed citizens were not opposed to prioritising groups at higher risks of adverse outcomes, but if resources and epidemiological conditions allow, achieving population benefits should be a strategic priority. These insights may inform future SARS-CoV-2 vaccination strategies.

Pastoral power in HIV prevention: Converging rationalities of care in Christian and medical practices in Papua New Guinea

In his conceptualisation of pastoral power, Michel Foucault argues that modern healthcare practices derive a specific power technique from pastors of the early Christian church. As experts in a position of authority, pastors practise the care of others through implicitly guiding them towards thoughts and actions that effect self-care, and towards a predefined realm of acceptable conduct, thus having a regulatory effect. This qualitative study of healthcare workers from two Christian faith-based organisations in Papua New Guinea examines the pastoral rationalities of HIV prevention practices which draw together globally circulated modern medical knowledge and Christian teachings in sexual morality for implicit social regulation. Community-based HIV awareness education, voluntary counselling and testing services, mobile outreach, and economic empowerment programs are standardised by promoting behavioural choice and individual responsibility for health. Through pastoral rationalities of care, healthcare practices become part of the social production of negative differences, and condemn those who become ill due to perceived immorality. This emphasis assumes that all individuals are equal in their ability to make behavioural choices, and downplays social inequality and structural drivers of HIV risk that are outside individual control. Given healthcare workers' recognition of the structural drivers of HIV, yet the lack of language and practical strategies to address these issues, political commitment is needed to enhance structural competency among HIV prevention programs and healthcare workers.

Intramedullary Spinal Cord Tumors: Part II-Management Options and Outcomes

Study Design Broad narrative review. Objectives Intramedullary spinal cord tumors (IMSCT) are uncommon lesions that can affect any age group or sex. However, numerous IMSCT exist and the clinical course of each tumor varies. The following article addresses the various management options and outcomes in patients with IMSCT. Methods An extensive review of the peer-reviewed literature was performed, addressing management options and clinical outcomes of patients with IMSCT. Results Early diagnosis and intervention are essential to obtain optimal functional outcome. Each IMSCT have specific imaging characteristics, which help in the clinical decision-making and prognostication. A comprehension of the tumor pathology and the clinical course associated with each tumor can allow for the proper surgical and nonsurgical management of these tumors, and reduce any associated morbidity and mortality. Recent advances in the operative management of such lesions have increased the success rate of tumor removal while minimizing iatrogenic-related trauma to the patient and, in tandem, improving patient outcomes. Conclusions Awareness and understanding of IMSCT is imperative to design proper management and obtain optimal patient outcomes. Meticulous operative technique and the use of surgical adjuncts are essential to accomplish proper tumor removal, diminish the risk of recurrence, and preserve neurologic function. Operative management of IMSCT should be individualized and based on tumor type, location, and dimensional extensions. To assist with preoperative and intraoperative decision-making, a general algorithm is provided.

Standards for plant synthetic biology: a common syntax for exchange of DNA parts

Inventors in the field of mechanical and electronic engineering can access multitudes of components and, thanks to standardization, parts from different manufacturers can be used in combination with each other. The introduction of BioBrick standards for the assembly of characterized DNA sequences was a landmark in microbial engineering, shaping the field of synthetic biology. Here, we describe a standard for Type IIS restriction endonuclease-mediated assembly, defining a common syntax of 12 fusion sites to enable the facile assembly of eukaryotic transcriptional units. This standard has been developed and agreed by representatives and leaders of the international plant science and synthetic biology communities, including inventors, developers and adopters of Type IIS cloning methods. Our vision is of an extensive catalogue of standardized, characterized DNA parts that will accelerate plant bioengineering.

Intramedullary Spinal Cord Tumors: Part I-Epidemiology, Pathophysiology, and Diagnosis

Study Design Broad narrative review. Objectives Intramedullary spinal cord tumors (IMSCT) are rare neoplasms that can potentially lead to severe neurologic deterioration, decreased function, poor quality of life, or death. As such, a better understanding of these lesions is needed. The following article, part one of a two-part series, addresses IMSCT with regards to their epidemiology, histology, pathophysiology, imaging characteristics, and clinical manifestations. Methods The authors performed an extensive review of the peer-reviewed literature addressing the aforementioned objectives. Results Numerous IMSCT exist with varying epidemiology. Each IMSCT has its own hallmark characteristics and may vary with regards to how aggressively they invade the spinal cord. These lesions are often difficult to detect and are often misdiagnosed. Furthermore, radiographically and clinically, these lesions may be difficult to distinguish from one another. Conclusions Awareness and understanding of IMSCT is imperative to facilitate an early diagnosis and plan management.

Comparison of symptomatic cerebral spinal fluid leak between patients undergoing minimally invasive versus open lumbar foraminotomy, discectomy, or laminectomy

OBJECTIVE

Minimally invasive spine surgery (MISS) techniques have similar long-term outcomes compared to open surgery for patients undergoing 1- or 2-level discectomy, foraminotomy, or laminectomy. However, the rate of cerebrospinal fluid (CSF) leaks with both techniques has not been well established in the literature. This study sought to compare the rate and clinical impact of CSF leak in open lumbar foraminotomy, discectomy, or laminectomy with comparable MISS approaches.

METHODS

A total of 863 patients undergoing 1- or 2-level discectomy, foraminotomy, or laminectomy by either MISS an open technique were evaluated for CSF leaks. Variables assessed included operative time, blood loss, CSF leaks, hospital stay, days with lumbar drain, days of postoperative flat bed rest, and postoperative intervention. Statistical analyses include univariate analysis (Student t test, analysis of variance, odds ratio, χ(2)) and bivariate analysis (logistic regression).

RESULTS

In the MISS group there were 15 CSF leaks (4.7%), and 49 CSF leaks (9.0%) in the open group. Eight patients in the open group required lumbar drainage, compared to zero patients in the MISS group. Twelve patients required reoperation for persistent CSF leak in the open group, compared to zero patients in the MISS group. Patients undergoing open spine surgery were 2 times more likely to have a CSF leak (odds ratio = 2.3, 95% confidence interval = 1.2 to 3.7, P = .01). Patients undergoing MISS had significantly lower reoperation rates for CSF leak repairs (open = 25% of open CSF leak cases, MISS = 0%, P < .01).

CONCLUSIONS

In this study, there was a statistically significant decreased rate of CSF leak between an MISS approach and an open surgical approach. Furthermore, CSF leaks in open surgery have a higher probability of requiring lumbar drainage or reoperation to repair the durotomy.

Abdominal complications following posterior spinal fusion in patients with previous abdominal surgeries

Perioperative abdominal complications associated with spine surgery are rare. Although most known abdominal complications occur in conjunction with anterior spinal fusions, there is a paucity of reports reviewing abdominal complications occurring with posterior spinal fusions. The authors review 4 patients who experienced a perioperative abdominal complication following a posterior spinal fusion. In each of these patients, a history of abdominal surgery is present. Given the physiological changes that occur with surgery in the prone position, patients with previous abdominal surgeries are at risk for developing abdominal complications in the perioperative period.

Management of recurrent adult tethered cord syndrome

Recurrent tethered cord syndrome (TCS) can lead to significant progressive disability in adults. The diagnosis of TCS is made with a high degree of clinical suspicion. In the adult population, many patients receive inadequate care unless they are seen at a multidisciplinary clinic. Successful detethering procedures require careful intradural dissection and meticulous wound and dural closure. With multiple revision procedures, vertebral column shortening has become an appropriate alternative to surgical detethering.

A Pediatric Patient With a Dissecting Thrombotic Anterior Choroidal Artery Aneurysm

OBJECTIVE

We report a unique case of a dissecting thrombosed left anterior choroidal aneurysm.

CLINICAL PRESENTATION

The aneurysm was diagnosed in a pediatric patient who presented with right-sided hemiparesis. Computed tomography, computed tomographic angiography, magnetic resonance imaging, and conventional angiography studies were helpful in diagnosing the aneurysm in this patient. Imaging was consistent with an acute infarct in the left globus pallidus.

INTERVENTION

An orbitozygomatic craniotomy was performed for surgical clipping of the aneurysm.

CONCLUSION

This case illustrates the unique appearance of a dissecting aneurysm in the anterior choroidal artery and stresses the importance of recognizing atypical presentations of complex aneurysms in the pediatric population.

Osteophyte formation after multilevel anterior cervical discectomy and fusion causing a delayed presentation of functional dysphagia

BACKGROUND CONTEXT

Anterior cervical discectomy and fusion (ACDF) is a common procedure used to treat radiculopathy and myelopathy from cervical degenerative disc disease. The complications for this procedure are well known. Dysphagia can occur in the postoperative setting. However, it is typically transient and does not last longer than 1 month after an operation. A de novo presentation of dysphagia occurring years after an operation is unique. Osteophyte formation can cause mass effect on the esophagus leading to obstruction of this conduit. However, there have been no reported cases of osteophyte growth fusing to surrounding structures leading to a functional dysphagia.

PURPOSE

The authors describe a delayed presentation of functional dysphagia 9 years after an ACDF. This resulted from osteophyte formation originating from the cervical plate and tethering the thyroid cartilage and hyoid bone, thus limiting mobilization of the larynx.

STUDY DESIGN/SETTING

Case report.

METHODS

The osteophyte was disconnected at the origin of the plate allowing the contents of the neck to move independently.

RESULT

After removal of the osteophyte complex at the base of the cervical plate, this patient experienced resolution of his dysphagia.

CONCLUSION

Functional dysphagia can occur in a delayed fashion after ACDF from osteophytes tethering the cervical plate to the surrounding contents of the neck used for swallowing. Freeing the contents of the neck from the tethering osteophytes can alleviate symptoms related to a dysfunctional swallowing mechanism.

Surgical management of superficial siderosis

BACKGROUND CONTEXT

Superficial siderosis is a rare condition resulting from the presence of chronic bleeding into the subarachnoid space usually causing gait instability and deafness. The surgical management of superficial siderosis depends on localizing the source of hemorrhage.

PURPOSE

The surgical treatment of this rare condition has not been well described in the literature. We present a case illustrating the surgical treatment for superficial siderosis.

STUDY DESIGN

Case report.

PATIENT SAMPLE

The authors describe the case report of a 70-year-old gentleman with gait instability and deafness found to have an abnormal communication between the spinal epidural venous plexus and the subarachnoid space.

METHODS

The source of hemorrhage into the subarachnoid space was identified to be a fistula in the ventral thoracic dural. A costotransversectomy approach was undertaken at the T4-T5 level to expose the fistula. The abnormal communication was patched and sealed.

RESULTS

The patient's symptoms remained stable on follow-up at 15 months with no worsening of his symptoms.

CONCLUSIONS

Superficial siderosis is a neurologic disorder that arises from chronic hemosiderin deposition into the subarachnoid space. The progressive nature of the disease can be halted if a source of hemorrhage can be found and treated surgically.

Direct identification of the Meloidogyne incognita secretome reveals proteins with host cell reprogramming potential

The root knot nematode, Meloidogyne incognita, is an obligate parasite that causes significant damage to a broad range of host plants. Infection is associated with secretion of proteins surrounded by proliferating cells. Many parasites are known to secrete effectors that interfere with plant innate immunity, enabling infection to occur; they can also release pathogen-associated molecular patterns (PAMPs, e.g., flagellin) that trigger basal immunity through the nematode stylet into the plant cell. This leads to suppression of innate immunity and reprogramming of plant cells to form a feeding structure containing multinucleate giant cells. Effectors have generally been discovered using genetics or bioinformatics, but M. incognita is non-sexual and its genome sequence has not yet been reported. To partially overcome these limitations, we have used mass spectrometry to directly identify 486 proteins secreted by M. incognita. These proteins contain at least segmental sequence identity to those found in our 3 reference databases (published nematode proteins; unpublished M. incognita ESTs; published plant proteins). Several secreted proteins are homologous to plant proteins, which they may mimic, and they contain domains that suggest known effector functions (e.g., regulating the plant cell cycle or growth). Others have regulatory domains that could reprogram cells. Using in situ hybridization we observed that most secreted proteins were produced by the subventral glands, but we found that phasmids also secreted proteins. We annotated the functions of the secreted proteins and classified them according to roles they may play in the development of root knot disease. Our results show that parasite secretomes can be partially characterized without cognate genomic DNA sequence. We observed that the M. incognita secretome overlaps the reported secretome of mammalian parasitic nematodes (e.g., Brugia malayi), suggesting a common parasitic behavior and a possible conservation of function between metazoan parasites of plants and animals.

Parasitic nematodes are microscopic worms that cause major diseases of plants, animals, and humans. Infection is associated with secretion of proteins by the parasite; these proteins suppress the immune system and cause other changes to host cells that are required for infection. Identification of secreted proteins has been difficult because they are released only in trace amounts. We have developed very sensitive methods that enabled the discovery of 486 proteins secreted by the root knot nematode, Meloidogyne incognita; prior to this, only a handful of secreted proteins were known. Several secreted proteins appear to mimic normal plant proteins, and they may participate in the process by which the nematode hijacks the plant cell for its own purposes. Meloidogyne species infect many crops, including corn, soybean, cotton, rice, tomato, carrots, alfalfa, and tobacco. The discovery of these secreted proteins could lead to new methods for protecting these important crops from nematode damage. We observed that the secretome of the human pathogen, Brugia malayi, overlaps that of M. incognita, suggesting a common parasitic behavior between pathogens of plants and animals.

Stiles-Crawford effect of the first kind: assessment of photoreceptor alignments following dark patching

Properties of presumed mechanisms controlling photoreceptor alignments are partially defined. A phototropic mechanism normally dominates alignment, but do modest changes in orientations occur with dark patching? Here, new photopic Stiles-Crawford (SCE-I) determinations were made before patching (pre-patch), just after 8-days of dark-patching (post-patch), and 3 days after patch removal (recovery test). We tested at 0, 11 and 22 degrees in the temporal retina of both eyes. Ten eyes of adult subjects were tested. SCE-I peak positions and Stile's parameter 'rho' were assessed. Dark-patching effects were small. Observations revealed meaningful corrective alignment overshoots with recovery in the light. Results suggest (1) the presence of multiple weak mechanisms affecting receptor alignments in the dark; (2) the phototropic mechanism to be dominant in the light; (3) the need for multiple test loci to be sampled in such studies, and (4) small changes in the SCE-I in the pupil plane can reflect meaningful events occurring at the retina.

Differences that matter: major cytotoxic T cell-stimulating minor histocompatibility antigens

Despite thousands of genetic polymorphisms among MHC matched mouse strains, a few unknown histocompatibility antigens are targeted by the cytotoxic T cells specific for tissue grafts. We isolated the cDNA of a novel BALB.B antigen gene that defines the polymorphic H28 locus on chromosome 3 and yields the naturally processed ILENFPRL (IFL8) peptide for presentation by Kb MHC to C57BI/6 CTL. The CTL specific for the IFL8/Kb and our previously identified H60/Kb complexes represent a major fraction of the B6 anti-BALB.B immune response. The immunodominance of these antigens can be explained by their differential transcription in the donor versus the host strains and their expression in professional donor antigen-presenting cells.

Refractive astigmatism acts predominantly as a source of high spatial frequency image distortion: the associated lineal distortions can be overcome by using a low pass spatial filter!

PURPOSE

Surprisingly, an important characteristic of astigmatism has been overlooked by ophthalmic and clinical scientists. Apparently, refractive astigmatism is due largely to a form of high spatial frequency image distortion.

METHODS

Characteristic astigmatic image distortion can be minimized or eliminated by using a low-pass spatial filter (here, a ground glass plate was employed for this purpose). The ground glass is placed a short distance in front of a visual acuity chart, or it may be used with other tests, such as vernier acuity.

RESULTS

This test has been performed by us on large numbers of patients and test subjects. A clinician can try this test for himself/herself. Place a +2.00 D.C. (any axis) lens in front of the eye; the usual distortions will be observed. Locate the ground glass plate as described. The usual distortions associated with the conoid of Stürm will not be visible or will be virtually eliminated, although some image blur will remain.

CONCLUSIONS

This technique has significance, e.g., in visual screening programs in developing nations, or in assessing patients with media disorders prior to ophthalmic surgery.

Structure-antimutagenic activity relationship study of plicatin B

A systematic structure-activity relationship study of plicatin B (1), an antimutagenic constituent of Psoralea juncea, was undertaken with a view toward elucidating its chemical mode of action and possibly optimizing its antimutagenic activity during the process. Compound 1 and its related analogues were examined for their antimutagenic activity against mutations induced by ethyl methanesulfonate, a direct acting mutagen and alkylating agent, in Salmonella typhimurium strain TA100, utilizing the modified Ames test protocol. The dihydro analogue 3 resulting from saturation of the conjugated alkene double bond of 1 was found to exhibit reduced cytotoxicity and enhanced efficacy relative to the parent compound. This result serves preliminarily to exclude a Michael acceptor role of the alpha,beta-unsaturated carbonyl moiety in connection with its antimutagenic activity.

Hydrophobicities of the nucleic acid bases: distribution coefficients from water to cyclohexane

To establish an experimental scale of hydrophobicities for the nucleic acid bases, comparable with a scale developed earlier for amino acid side-chains, these bases and their parent compounds (purine and pyrimidin-2-one) were converted to n-butylated and tetrahydrofurylated derivatives that are appreciably soluble in cyclohexane, a truly non-polar solvent that dissolves negligible water at saturation. Distribution measurements between neutral aqueous solution and cyclohexane, at varying solute concentrations, showed no evidence of self-association of the solute in either solvent, and the possibility of specific entrainment of water by solutes entering cyclohexane was ruled out by the results of experiments with tritiated water. In both the n-butyl and tetrahydrofuryl series, the bases span a range of approximately 5.3 kcal mol-1 in their free energies of transfer from water to cyclohexane, and are arranged in the following rank, in order of decreasing hydrophobicity: purine>thymine>adenine>uracil>pyrimidin-2-one>hypoxanthine>/=cytosine >/=guanine. In both series of pyrimidin-2-ones, hydrophobicity decreases with introduction of an amino substituent, but addition of an exocyclic keto group results in a modest enhancement of hydrophobicity; and free energies of transfer are relatively insensitive to the position of N-alkyl substitution. In both series of purines, hydrophobicity decreases with the introduction of exocyclic amino and keto groups, the keto group having the greater effect; and free energies of transfer vary substantially depending on the position of N-alkyl substitution. Several additional compounds were examined to test recent predictions based on SM5.4/A, a quantum mechanical self-consistent-field solvation model; and that model was found to yield values in reasonable agreement with the experimental results.

Enzyme-substrate complexes of adenosine and cytidine deaminases: absence of accumulation of water adducts

Adenosine deaminase has been reported to bind the product inosine (the substrate for the reverse reaction) as inosine 1,6-hydrate considered similar in structure to the transition state for adenosine deamination (Wilson & Quiocho, 1994) Accumulation on the enzyme of inosine 1,6-hydrate would be surprising, because this compound is an actual intermediate, probably approaching the transition state, in oxygen exchange between water and the C==O group of inosine, a reaction previously shown to be catalyzed by adenosine deaminase (Wolfenden & Kirsch, 1968). The equilibrium constant for conversion of ES to ES*, in the oxygen exchange reaction, is less than 10-12. To investigate the structure of enzyme-bound inosine in a different way, we labeled deoxyinosine with 13C, excepting an upfield shift of 70-110 ppm if significant rehybridization to sp3 had occurred at the carbonyl group. Instead, the results show a very small shift (1.3 ppm), indicating that C-6 of 2'-deoxyinosine retains its sp2 hybridization after binding by calf intestinal adenosine deaminase. In a separate series of experiments, [4,5-13C]-2'-deoxyuridine was synthesized and found to retain its sp2 hybridization at C-4, after binding by Escherichia coli cytidine deaminase, an enzyme that catalyzes 18O exchange from water into uridine. These findings are consistent with the general expectation, based on the unfavorable equilibrium of activation of enzyme-bound substrates, that enzymes should not accumulate appreciable concentrations of intermediates whose free energies approach that of the transition state in substrate transformation.

Thermal stability determinants of chicken egg-white lysozyme core mutants: hydrophobicity, packing volume, and conserved buried water molecules

A series of 24 mutants was made in the buried core of chicken lysozyme at positions 40, 55, and 91. The midpoint temperature of thermal denaturation transition (Tm) values of these core constructs range from 60.9 to 77.3 degrees C, extending an earlier, more limited investigation on thermostability. The Tm values of variants containing conservative replacements for the wild type (WT) (Thr 40-Ile 55-Ser 91) triplet are linearly correlated with hydrophobicity (r = 0.81) and, to a lesser degree, with combined side-chain volume (r = 0.75). The X-ray structures of the S91A (1.9 A) and I55L/S91T/D101S (1.7 A) mutants are presented. The former amino acid change is found in duck and mammalian lysozymes, and the latter contains the most thermostable core triplet. A network of four conserved, buried water molecules is associated with the core. It is postulated that these water molecules significantly influence the mutational tolerance at the individual triplet positions. The pH dependence of Tm for the S91D mutant was compared with that of WT enzyme. The pKa of S91D is 1.2 units higher in the native than in the denatured state, corresponding to delta delta G298 = 1.7 kcal/mol. This is a low value for charge burial and likely reflects the moderating influence of the buried water molecules or a conformational change. Thermal and chemical denaturation and far UV CD spectroscopy were used to characterize the in vitro properties of I55T. This variant, which buries a hydroxyl group, has similar properties to those of the human amyloidogenic variant I56T.

Design and structural analysis of an engineered thermostable chicken lysozyme

A hyperstable (hs) variant of chicken egg-white lysozyme with enhanced thermal (delta Tm approximately +10.5 degrees C) and chemical (delta Cm for guanidine hydrochloride denaturation = +1.3 M) stabilities relative to wild-type (WT) was constructed by combining several individual stabilizing substitutions. The free energy difference between the native and denatured states of the hs variant is 3.1 (GdnHCl, 25 degrees C) to 4.0 (differential scanning calorimetry, 74 degrees C) kcal mol-1 greater than that of WT. The specific activity of the hs variant is 2.5-fold greater than that of WT. The choice of mutations came from diverse sources: (1) The I55L/S91T core construct with delta Tm = 3.3 degrees C from WT was available from the accompanying study (Shih P, Holland DR, Kirsch JF, 1995, Protein Sci 4:2050-2062). (2) The A31V mutation was suggested by the better atomic packing in the human lysozyme structure where the Ala 31 equivalent is Leu. (3) The H15L and R114H substitutions were selected on the basis of sequence comparisons with pheasant lysozymes that are more stable than the chicken enzyme. (4) The D101S variant was identified from a screen of mutants previously prepared in this laboratory. The effects of the individual mutations on stability are cumulative and nearly additive.