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Background: Randomized data comparing outcomes of transcatheter aortic valve replacement (TAVR) with surgery in low-surgical risk patients at time points beyond 2 years is limited. This presents an unknown for physicians striving to educate patients as part of a shared decision-making process., Objectives: The authors evaluated 3-year clinical and echocardiographic outcomes from the Evolut Low Risk trial., Methods: Low-risk patients were randomized to TAVR with a self-expanding, supra-annular valve or surgery. The primary endpoint of all-cause mortality or disabling stroke and several secondary endpoints were assessed at 3 years., Results: There were 1,414 attempted implantations (730 TAVR; 684 surgery). Patients had a mean age of 74 years and 35% were women. At 3 years, the primary endpoint occurred in 7.4% of TAVR patients and 10.4% of surgery patients (HR: 0.70; 95% CI: 0.49-1.00; P = 0.051). The difference between treatment arms for all-cause mortality or disabling stroke remained broadly consistent over time: -1.8% at year 1; -2.0% at year 2; and -2.9% at year 3. The incidence of mild paravalvular regurgitation (20.3% TAVR vs 2.5% surgery) and pacemaker placement (23.2% TAVR vs 9.1% surgery; P < 0.001) were lower in the surgery group. Rates of moderate or greater paravalvular regurgitation for both groups were <1% and not significantly different. Patients who underwent TAVR had significantly improved valve hemodynamics (mean gradient 9.1 mm Hg TAVR vs 12.1 mm Hg surgery; P < 0.001) at 3 years., Conclusions: Within the Evolut Low Risk study, TAVR at 3 years showed durable benefits compared with surgery with respect to all-cause mortality or disabling stroke. (Medtronic Evolut Transcatheter Aortic Valve Replacement in Low Risk Patients; NCT02701283)., Competing Interests: Funding Support and Author Disclosures Medtronic (Minneapolis, Minnesota) supplied funding for this study. Dr Forrest has received grant support/research contracts and consultant fees/honoraria/Speakers Bureau fees from Edwards Lifesciences and Medtronic. Dr Deeb has served on an advisory board for Medtronic; has received institutional grant support from Boston Scientific, Edwards Lifesciences, and Medtronic; and has received fees as a proctor for the Medtronic-sponsored SMART (Small Annuli Randomized to Evolut or SAPIEN Trial). Dr Yakubov has received grants and personal fees from Medtronic and Boston Scientific. Dr Gada has received personal fees from Medtronic, Abbott Vascular, Becton Dickenson, and Boston Scientific. Dr Mumtaz has served as a consultant to and has received honoraria and research grants from Edwards Lifesciences, the Japanese Organization for Medical Device Development, Medtronic, and Z-Medical. Dr Ramlawi has received grants, personal fees, and nonfinancial support from Medtronic, Liva Nova, and AtriCure. Dr Bajwa has received fees for consulting and proctoring from Medtronic. Dr Teirstein has received research grant and honoraria from Abbott, Boston Scientific, Cordis, and Medtronic; and has served on an advisory board for Boston Scientific and Medtronic. Dr Rutkin has served as a consultant to and has received speaking honoraria from Edwards Lifesciences and Medtronic. Dr Chawla has served as a proctor for Medtronic. Dr Chetcuti has received grants from Edwards Lifesciences, WL Gore Medical, Medtronic, and Boston Scientific; and has received personal fees from Medtronic, Boston Scientific, and Jena. Dr Stoler has served as a consultant to and has received honoraria from Biotronik Inc, Boston Scientific Corporation, Edwards Lifesciences, and Medtronic. Dr Levack has received personal fees from Medtronic. Dr Goel has received personal fees from Edwards Lifesciences and Abbott; and has served as a consultant for Medtronic. Dr Tchétché has received honoraria or consultation fees from Abbott, Boston Scientific, Edwards Lifesciences, and Medtronic. Dr Oh has received grants from Medtronic Echo Core; and has received personal fees from Medtronic Consulting. Dr Huang is a full-time employee and shareholder for Medtronic. Dr Popma is a full-time employee and shareholder for Medtronic. Dr Kleiman has received research grants from Medtronic, Abbott, Edwards Lifesciences, and Boston Scientific. Dr Reardon has received research grants from Abbott, Boston Scientific, WL Gore Medical, and Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: To evaluate whether transcatheter or surgical aortic valve replacement (TAVR or SAVR) affects clinical and haemodynamic outcomes in symptomatic patients with moderately-severe aortic stenosis (AS)., Methods: Echocardiographic evidence of severe AS for enrolment in the Evolut Low Risk trial was based on site-reported measurements. For this post hoc analysis, core laboratory measurements identified patients with symptomatic moderately-severe AS (1.02 , 3.02 , peak velocity 3.7±0.2 m/s, MG 32.7±4.8 mm Hg and aortic valve calcium volume 588 (364, 815) mm 3 . Valve haemodynamics improved following TAVR (AVA 2.5±0.7 cm 2 , peak velocity 1.9±0.5 m/s and MG 8.4±4.8 mm Hg; p<0.001 for all) and SAVR (AVA 2.0±0.6 cm 2 , peak velocity 2.1±0.4 m/s and MG 10.0±3.4 mm Hg; p<0.001 for all). At 24 months, the rates of death or disabling stroke were similar (TAVR 7.7% vs SAVR 6.5%; p=0.82). Kansas City Cardiomyopathy Questionnaire overall summary score assessing quality of life improved from baseline to 30 days after TAVR (67.0±20.6 to 89.3±13.4; p<0.001) and SAVR (67.5±19.6 to 78.3±22.3; p=0.001)., Conclusions: In symptomatic patients with moderately-severe AS, AVR appears to be beneficial. Determination of the clinical and haemodynamic profile of patients who can benefit from earlier isolated AVR needs further investigation in randomised clinical trials., Competing Interests: Competing interests: SI supports the echocardiographic core laboratory for Medtronic trials. RL has received research grants from Medtronic, Boston Scientific and Abbott Vascular. VTN has nothing to disclose. JKF has received grant support/research contracts and consultant fees/honoraria/speakers’ bureau fees from Edwards Lifesciences and Medtronic. MJR has received fees to his institution from Medtronic for consulting and providing educational services. SHL has received research grants from Abbott and Medtronic. AHM serves as a consultant and has received honoraria from Edwards Lifesciences, Medtronic, Japanese Organisation for Medical Device Development and Z-Medica. HG serves as a consultant for Abbott, Bard, Edwards Lifesciences and Medtronic. TB reports fees for consulting and proctoring from Medtronic. DL has nothing to disclose. JoH has nothing to disclose. AC serves as a proctor for Medtronic. BJ has nothing to disclose. GA is a consultant and serves as a proctor and is on the advisory board of Medtronic and is a consultant for Abbott Vascular. MM has nothing to disclose. JiH is an employee and shareholder of Medtronic. JKO is the director of the echocardiographic core laboratory for Medtronic trials and a consultant for Medtronic. He also receives research grant from REDNVIA for EVOID AS trial., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

A novel canine papillomavirus, CfPV-2, was cloned from a footpad lesion of a golden retriever. Unlike the known canine oral papillomavirus (COPV), which has a double-stranded DNA genome size of 8607 bps, the genome of CfPV-2 is 8101 bps. Some of this size difference is due to an abbreviated early-late region (ELR), which is 1200 bps shorter than that of COPV. However, CfPV-2 has other differences from COPV, including the presence of an E5 ORF between the E2 gene and the ELR and an enlarged E4 ORF (one of the largest PV E4 open reading frames). The genome of CfPV-2 shares low homology with all the other papillomaviruses and, even in the most highly conserved ORF of L1, the nucleotide sequence shares only 57% homology with COPV. Due to this highly divergent DNA sequence, CfPV-2 establishes a new PV genus, with its closest phylogenetic relatives being amongst the Xi and Gamma genuses. CfPV-2 also has unique biological features; it induces papillomas on footpads and interdigital regions which, if infection is persistent, can progress to highly metastatic squamous cell carcinoma. CfPV-2 does not induce oral papillomas in immunocompetent animals and antibodies generated against COPV and CfPV-2 are type-specific. The availability of a new canine papillomavirus with differing genetic and biological properties now makes it possible to study type-specific host immune responses, tissue tropism and the comparative analysis of viral gene functions in the dog.

Background: An avian papillomavirus genome has been cloned from a cutaneous exophytic papilloma from an African grey parrot (Psittacus erithacus). The nucleotide sequence, genome organization, and phylogenetic position of the Psittacus erithacus papillomavirus (PePV) were determined. This PePV sequence represents the first complete avian papillomavirus genome defined., Results: The PePV genome (7304 basepairs) differs from other papillomaviruses, in that it has a unique organization of the early protein region lacking classical E6 and E7 open reading frames. Phylogenetic comparison of the PePV sequence with partial E1 and L1 sequences of the chaffinch (Fringilla coelebs) papillomavirus (FPV) reveals that these two avian papillomaviruses form a monophyletic cluster with a common branch that originates near the unresolved center of the papillomavirus evolutionary tree., Conclusions: The PePV genome has a unique layout of the early protein region which represents a novel prototypic genomic organization for avian papillomaviruses. The close relationship between PePV and FPV, and between their Psittaciformes and Passeriformes hosts, supports the hypothesis that papillomaviruses have co-evolved and speciated together with their host species throughout evolution.

The purpose of this study was to determine graft patency and blood flow rates in recipients of a new cuffed ePTFE graft (Venaflo graft) used for hemodialysis access. A pilot study was conducted with 12 (7 men, 5 women) consecutive patients (age range, 36-76 yr; mean, 65 yr). All patients were recipients of a new cuffed PTFE graft placed for hemodialysis access. Seven were high risk because of a prior history of clotted hemodialysis accesses (1-6; mean, 3.3). Blood flow rates were determined by ultrasound dilution technique at 3 month intervals. One year and 2 year overall graft patency rates were 90.9% and 68.2%, respectively. One graft (high risk, six prior grafts) was lost to thrombosis in the first year; two grafts (one high risk, four prior grafts) were lost to thrombosis in the second year of follow-up. No graft thrombosis resulted from stenosis at the graft-vein anastomosis. Blood flow rates ranged from 550 to 2,110 ml/min (mean, 1,086 ml/min; n = 8) when first measured 3 months after graft placement. Similar flow rates were observed at 12 months (mean, 1,043 ml/min; n = 7) and 24 months (mean, 1,014 ml/min; n = 4) in grafts available for comparison. Dialysis flow rates in excess of 350 ml/min were possible with all patent grafts. A cuffed ePTFE graft provided stable blood flow and satisfactory graft patency during 2 years of follow-up, even in high risk patients with a prior history of vascular access thrombosis.

Our objective was to determine whether patients with chronic renal failure requiring maintenance hemodialysis retain intrinsic renal function longer when using reprocessed polysulfone (PS) membrane hemodialyzers or single-use cellulose acetate (CA) membrane hemodialyzers. Fifty consecutive patients with residual renal function (urea clearance > 2.0 mL/min) using PS dialyzers were compared with a retrospective, disease- and time-matched population of patients using CA dialyzers. Endogenous urea clearance was measured every 3 months in all patients with remaining residual function. Other data collected included age, sex, cause of chronic renal failure, use of angiotensin-converting enzyme inhibitors or calcium channel blockers, and hemodynamic stability during hemodialysis. All patients were observed for at least 6 months while using a single type of dialyzer. Study end points included loss of residual renal function (urea clearance < 1.0 mL/min), death, transplant, transfer to peritoneal dialysis, or change of dialyzer. The PS and CA groups of patients were well matched for sex, age, initial renal clearance, predialysis blood pressure, and hemodynamic stability during hemodialysis. The PS patients had a higher delivered Kt/V (1.34 +/- 0.30 [mean +/- SD]) than the CA patients (1.06 +/- 0.20). The PS group had a higher average urea clearance than the CA group after 4 to 9 months of dialysis (2.8 +/- 2.6 mL/min v 1.7 +/- 1.6 mL/min, respectively), after 10 to 15 months of chronic dialysis (2.0 +/- 2.4 mL/min v 1.1 +/- 1.5 mL/min, respectively), and after 16 to 21 months of dialysis (1.3 +/- 1.9 mL/min v 0.5 +/- 1.1 mL/min, respectively; all P < 0.03, t-test). After 22 to 24 months of dialysis, the difference between the two groups was not significant. When comparing patients with identical causes of chronic renal failure, there were no differences between the PS and CA groups for those with diabetes mellitus, tubulointerstitial disease, or polycystic disease. Patients with parenchymal renal disease (glomerulonephritis or nephrosclerosis) had markedly better retention of intrinsic renal function with PS than with CA dialyzers (all P < 0.01). Kaplan-Meier analysis for retention of intrinsic renal function showed that PS patients with parenchymal renal disease had a mean of 23 months before loss of intrinsic renal function, whereas for CA patients the mean was 11 months before loss of intrinsic renal function (P = 0.0005). Cellulose acetate patients lost renal function at an average rate of 0.27 +/- 0.22 mL/min/mo, whereas for PS patients the rate was 0.14 +/- 0.56 mL/min/mo (P = 0.06, rank sum). CA patients with parenchymal renal disease lost renal function at a rate of 0.29 +/- 0.22 mL/min/mo, whereas for PS patients the rate was 0.0 +/- 0.8 mL/min/mo (P = 0.004, rank sum). Age, sex, and the use of either angiotensin-converting enzyme inhibitors or calcium channel blockers did not have an effect on the loss of intrinsic renal function. Patients with nondiabetic parenchymal renal disease receiving chronic hemodialysis with hydrogen peroxide/peroxyacetic acid-reprocessed PS dialyzers and a higher Kt/V lose residual renal function at a slower rate than disease-matched patients using single-use CA dialyzers. Our findings provide further evidence that the choice of dialyzer membrane may have an effect on intrinsic renal function.

Gangliosides, complex glycolipids of the nervous system cell membranes, have been found effective both in reducing the degree of ischemic injury and in stimulating neuronal regeneration during the recovery period. In order to investigate their neuroprotective effect during spinal cord ischemia, 60 male Sprague-Dawley rats underwent occlusion of the thoracic aorta and both subclavian arteries for 13 min. In the postoperative period, function of hindlimbs was appraised, daily for 30 days, by a deficit score (0-15). The animals were then killed and spinal cord injury was assessed by a histologic score (0-3) based on the degree of gray and white matter gliosis, number of motor neurons, and white matter myelination. The rats received intraperitoneal injection of placebo (n = 29) or GM-1 30 mg/kg (n = 31) daily, from 2 days prior to surgery to 15 days after. The scores of each group for each day were analyzed by repeated measures analysis of variance. The rate of recovery was better for GM-1 (P < 0.001) from the 15th to the 30th day. A trend was seen toward lower scores in the GM-1 group (P = 0.056). Mean histologic scores (placebo = 1.14 +/- 0.23 SE, GM-1 = 1.58 +/- 0.22 SE) did not differ (Wilcoxon, P = 0.17). The present data support the hypothesis that functional improvement after spinal cord ischemia due to aortic occlusion is enhanced by the administration of gangliosides. Optical microscopy could document only irreversible injury and might not be sensitive enough to detect subtle changes during recovery of neural elements.

A case is presented in which bone biopsy results helped to resolve not only difficult issues in the clinical management of the patient's renal osteodystrophy but also disruptive psychosocial problems surrounding her clinical course. The outcome was a satisfactory resolution based on rational medical treatment and directed supportive care. The presentation highlights important principles in the procurement, processing, and interpretation of the bone biopsy, while also addressing the importance of accurate diagnosis in facilitating the overall long-term management by the entire renal team.

Twenty-one hemodialysis patients were studied during 25 dialysis sessions with a dialysate sodium of 140 mEq/L and during 25 sessions with a high and variable sodium dialysate (145 mEq/L decreased to 140 mEq/L). Bicarbonate dialysate and ultrafiltration-controlled dialysis equipment were used. Neither the average interdialytic weight gain nor the predialysis and postdialysis blood pressures changed. The need for 5% saline infusions decreased from 168 + 137 ml/patient to 2 + 6 ml/patient for 25 dialyses. Use of 0.9% saline boluses remain unchanged. Fewer dialysis sessions required the use of the Trendelenburg position (p < .02) or a decrease in the transmembrane pressure (p < .05). With the use of high and variable sodium dialysate concentration, patients had less symptomatic hypotension (p < .05) and fewer symptoms of dialysis dysequilibrium, such as cramps or nausea.

We report a case of atrial septal rupture and surgical cure after blunt chest trauma. Review of the literature indicates that this rare lesion results from severe forces applied to the chest and is often associated with other serious and life-threatening injuries. The defect may not be recognized for several months or even years in patients who survive concomitant initial trauma. When operative repair is undertaken, a favorable outcome can be anticipated.

We report a case of stab wound to the heart resulting in an atrial septal defect and perforation of the anterior leaflet of the mitral valve, which we repaired successfully 7 years after the injury. To our knowledge, repair of an atrial septal defect due to penetrating trauma has never before been reported. Investigation of possible valvular heart disease in a patient with a history of chest trauma should be aimed at identifying both intracardiac shunts and valvular abnormalities, so that a complete repair can be performed.

Formalin-fixed, paraffin-embedded tissue blocks from 13 women with cervical carcinoma that recurred following radiation therapy were evaluated for the presence of human papillomavirus (HPV) by in situ hybridization using ribonucleic acid 35S-labeled probes for HPV types 6, 11, 16, and 18. Ten of thirteen patients also had pretreatment biopsies from their primary tumors available for analysis. HPV 16 was detected in both primary and recurrent lesions in 4 women. In 1 case, HPV was detected in the primary tumor and not in the recurrence. HPV 16 was also present in three recurrent cancers from which primary lesions were not available for probing. Radiation therapy did not alter the hybridization signal strength or pattern, suggesting that the HPV genome copy number was not significantly affected. The persistence of HPV 16 in recurrent cervical carcinoma is consistent with the theory that HPV plays a role in maintaining the malignant state.

Seizures, hypertensive encephalopathy, transient ischemic attacks, and thrombosis of hemodialysis accesses occurred in early clinical trials with recombinant human erythropoietin. To determine if these events may be caused by the increased hematocrit value or some direct effect of the recombinant human hormone, 10 transfusion-dependent hemodialysis patients were divided into two groups of five according to their serum ferritin concentration: group A. less than 800 microgram/liter, and group B. greater than 800 micrograms/liter. After a month of placebo administration, recombinant human erythropoietin was given (150 U/kg intravenously thrice weekly) for four months and then stopped for one month. Hematocrit values were maintained at 0.33 +/- 0.02 (mean +/- SD) by dose adjustment in group A and at 0.26 +/- 0.02 by thrice weekly phlebotomies in group B, who received a constant dose of erythropoietin. Viscosity increased from subnormal to normal in group A (P less than 0.02) and cerebral blood flow decreased from above normal to normal (P less than 0.02). In group B minor, statistically insignificant, changes in viscosity and reciprocal changes in cerebral blood flow also occurred. There was no change in either group in transcutaneous oxygen tension. Bleeding time decreased toward normal in both groups during recombinant human erythropoietin administration but the changes did not reach statistical significance. Fibrinogen levels were increased in all patients but remained unchanged. No other significant coagulation-related changes were observed. Recombinant erythropoietin in the dosage and schedule of administration described in this study did not lead directly or indirectly to changes likely to precipitate seizures or intravascular thrombosis.

A two-step procedure employing gel filtration and anion exchange chromatography has been utilized to isolate LMW immunoglobulin from the horned shark, Heterodontus francisci. Light chains obtained by complete reduction and alkylation of the parent protein have been compared by several analytical techniques. Amino acid composition data implies a limited degree of variation in the light chains isolated from individual animals. Polyacrylamide gel electrophoresis of the CNBr digests of the light chains reveal indistinguishable banding profiles of the major peptides. Isoelectric focusing indicates limited heterogeneity in the light chain spectrotype and identity in the pI of the majority of bands detectable by staining. The suggested degree of structural similarity in the light chains of this phylogenetically primitive shark is discussed in terms of the evolutionary position of the species and current theories concerning the origins of structural diversity in immunoglobulins.

When subjected to polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS), the fully reduced and alkylated heavy chains isolated from three monoclonal IgG1 cryoimmunoglobulins exhibited various degrees of retardation in mobility when compared to noncryoglobulin references. The anomalous electrophoretic mobility was not correlated with the thermal magnitude of cryoprecipitation of the individual proteins. High sensitivity analytical gel filtration in 5 M guanidine-HCl failed to distinguish heavy chains of the cryoimmunoglobulins from noncryoglobulin references, suggesting that the proteins possess equivalent molecular weights. Other possible causes for the anomalous mobility such as atypical amino acid and carbohydrate composition, charge and quantitative SDS binding do not appear to be likely. It remains possible that the shape and/or charge of the SDS-protein complexes are unique. Examination of the gel electrophoretic mobility in SDS of fully reduced and alkylated Fab components suggests that the Fd portion of these proteins may be abnormal. The gel electrophoresis anomaly is the only atypical structural feature thus detected which is shared by these three monoclonal cryoimmunoglobulins.

The principal target amino acid residue for covalent binding of metabolically activated [3H]benzo[a]pyrene (B[a]P) to histone 1 (H1) has been identified. Highly purified calf thymus H1 was modified by incubation with [3H]B[a]P in the presence of rat liver microsomes. The relative distribution of [3H]B[a]P versus specific amino acids among the N-bromo-succinimide peptides of H1 suggested that lysine may be the target. This was tested by selectively blocking the nucleophilic amino groups of lysine by amidination prior to [3H]B[a]P binding. Increasing levels of amidination of H1 resulted in corresponding decreases in the reactivity of this histone toward [3H]B[a]P. Amidination of 93% of the lysines blocked 87% of the [3H]B[a]P binding indicating that lysine was the principal target. N-terminal amino acid sequencing of [3H]B[a]P-modified H1 confirmed that lysine residues had bound [3H]B[a]P.

Five patients undergoing long-term hemodialysis with transfusional iron overload received treatment for 18 weeks with a regimen of recombinant human erythropoietin (150 U/kg) and regular phlebotomy to maintain the hematocrit value at 25% and reduce the total body iron burden. In the 149 phlebotomy sessions performed in these patients, a mean of 228 +/- 8 ml (mean +/- SEM) of whole blood was removed; it had a hematocrit value of 27.7% +/- 0.2%. The iron content of the erythrocytes removed (erythrocyte iron concentration, 787 +/- 11 micrograms/ml in 133 samples) accounted for more than 99% of the total iron removal by phlebotomy. Serum iron (serum iron concentration, 1.57 +/- 0.09 micrograms/ml in 65 samples) accounted for an insignificant fraction of the total iron removed. The iron removed at each phlebotomy session averaged 49.1 +/- 2.0 mg, similar to the amount of iron removed with deferoxamine administration in patients undergoing dialysis who had iron overload, but without the potential for adverse side effects reported with long-term deferoxamine therapy. Total iron removal during the 18 weeks of this study ranged from 732 to 2797 mg. Mean serum ferritin level decreased from 3189 +/- 1076 micrograms/L to 1676 +/- 342 micrograms/L (p less than 0.02, Wilcoxon signed rank test). When compared with a group of five patients without transfusional iron overload who received recombinant human erythropoietin and did not undergo therapeutic phlebotomy, the patients with iron overload had much greater iron losses and a larger decrease in serum ferritin levels.(ABSTRACT TRUNCATED AT 250 WORDS)

The heavy and light chains of pooled antibodies of the hybodont shark,Heterodontus francisci (horned shark), were subjected to amino acid sequence analysis. Yield determinations showed that more than 90% of the available polypeptides in the respective pools were sequenced. The heavy chains were homogeneous in the initial framework segment and showed a sequence homology of approximately 70% with the corresponding region of the more recently evolved nurse shark and a 45% homology with a human myeloma heavy chain. The light chains were less homogeneous and not identifiable as either kappa or lambda chains as known in higher species. The first half-cystine characteristics of the variable domain intrachain disulfide bridge of immunoglobulins was present in the same position (22 for heavy chains; 23 for light chains) in the horned shark as in mammalian species. The sequence analysis also suggested the presence of a hypervariable region in the horned shark light chains. The combined data imply that the antigen-binding function of immunoglobulins is mediated in much the same manner in this primitive shark as in more recently evolved species, including mammals.

The amino acid sequence of the VH region of McE, a monoclonal IgM cryoimmunoglobulin, has been determined employing automated sequencing methodology. Digestion of the intact Fab mu component, derived by trypsin cleavage of the parent protein at elevated temperature with CNBr, followed by complete reduction and alkylation, yielded the intact light chain as well as the 2 CNBr fragments that constituted the VH. N-terminal sequencing of the larger unblocked CNBr fragment, along with a component fragment derived by cleavage by BNPS-Skatole, established the structure of the VH from position 88 through the V leads to C switch region. Citraconylation of the smaller, blocked fragment effected sufficient solubilization for enzymatic deblocking and direct sequencing of the N-terminal 20 residues of the VH. Complete trypsin digestion of the N-terminal CNBr fragment yielded 9 peptides that could be isolated by preparative cation exchange chromatography and gel filtration. The complete sequence of these peptides along with 4 chymotryptic peptides completed the primary structure of the VH region. The primary structure of McE appears to resemble that of He, previously identified as belonging to the VH II subgroup. The presence of characteristic CDR and FR regions as well as the identification of a probable site of glycosylation suggest that the cryoimmunoglobulin closely resembles noncryoglobulins in terms of overall structural composition. The cryoglobulin property may arise through alterations in individual residues or unfavorable arrangements of CDR and FR segments.

The amino acid sequences of the VH-domains from two human cryoimmunoglobulins have been compared with one another and with the VH-domains of noncryoglobulins by the mathematical method of metric analysis. The VHII sequence of McE [Gerber-Jenson et al. (1981), J. Immun. 126, 1212-1216] and the VHIII sequence of Hil [Chiu et al (1979), Biochemistry, 18, 553-560] resemble much more closely the VH-sequences of noncryoglobulins from their own subgroups than they resemble one another. Neither cryoglobulin sequence contains an unusual insertion or deletion of residues. Based on the crystallographic structure of the VHII domain in the Fab fragment of the human noncryoglobulin Newm [Saul et al. (1978), J biol. Chem., 253, 585-597], McE and Hil each contain two unprecedented residues in the outer beta-sheet structure of the VH-domain. The inwardly directed sidechains of Gly-71 and Ile-84 in McE may perturb the internal hydrophobic interactions and normal folding of adjacent segments of the outer beta-sheet from the third framework region. In contrast, the outwardly directed sidechains of Ile-23 and Arg-77 in Hil may perturb the external hydrophilic properties and folding of adjacent segments of the outer beta-sheet from the first and third framework regions. Thus, the monoclonal immunoglobulins McE and Hil may display cold-induced insolubility by different perturbations of the outer surface of the VH-domain. In each case, the unprecedented framework residues that mnay be responsible could have arisen by two point mutations involving single base changes.

By using monoclonal antibodies to different Epstein-Barr virus (EBV) polypeptides in combination with immunoblotting, we detected antigens associated with EBV replication in extracts from nasopharyngeal carcinoma (NPC) biopsy specimens. Major polypeptides associated with both the diffuse and the restricted components of the early antigen (EA) complex were found in extracts from nine of nine NPC biopsy specimens. Cells from an additional NPC biopsy specimen, passaged repeatedly in nude mice, were found to be positive for the major EA (restricted) polypeptide. This approach revealed that extracts from three of 14 biopsy specimens form other benign and malignant diseases also expressed these viral polypeptides. Therefore, for the first time, these results conclusively demonstrate the presence of EA polypeptides in extracts from NPC biopsy specimens. This finding provides at least a partial explanation for the reported prognostic value of antibodies to this antigen in patients with this disease.