Sintering of biphasic calcium phosphates.

Biphasic calcium phosphate (BCP) discs were fabricated and then sintered using two different sintering programs to establish whether the phases present could be controlled at low and high sintering temperatures. X-ray diffraction (XRD) was used to establish the phases present after sintering and scanning electron microscopy (SEM) determined the microstructure. Sintering program 1 involved a simple heating and cooling schedule and temperatures of 1100, 1250, 1275 and 1300 degrees C. It produced samples containing an additional alpha-tricalcium phosphate (alpha-TCP) phase at temperatures above 1100 degrees C. The original ratio of hydroxyapatite/beta-tricalcium phosphate (HA/beta-TCP) could not be maintained above this temperature. Sintering program 2 combined the heating and cooling schedules of the first program with a 900 degrees C hold stage to allow alpha-TCP to beta-TCP conversion to take place. At temperatures of 1250 and 1275 degrees C, this program was successful in completely removing the alpha-TCP phase and preserving the HA:beta-TCP ratio. The SEM results show that the surface morphology of the discs was not greatly affected by choice of sintering program.

Acquired cancer resistance to combination immunotherapy from transcriptional loss of class I HLA.

Understanding mechanisms of late/acquired cancer immunotherapy resistance is critical to improve outcomes; cellular immunotherapy trials offer a means to probe complex tumor-immune interfaces through defined T cell/antigen interactions. We treated two patients with metastatic Merkel cell carcinoma with autologous Merkel cell polyomavirus specific CD8+ T cells and immune-checkpoint inhibitors. In both cases, dramatic remissions were associated with dense infiltration of activated CD8+s into the regressing tumors. However, late relapses developed at 22 and 18 months, respectively. Here we report single cell RNA sequencing identified dynamic transcriptional suppression of the specific HLA genes presenting the targeted viral epitope in the resistant tumor as a consequence of intense CD8-mediated immunologic pressure; this is distinguished from genetic HLA-loss by its reversibility with drugs. Transcriptional suppression of Class I loci may underlie resistance to other immunotherapies, including checkpoint inhibitors, and have implications for the design of improved immunotherapy treatments.

Covalent disulfide binding of human IL-1 beta to alpha 2-macroglobulin: inhibition by D-penicillamine.

Secreted human IL-1 beta is known to have two free SH groups due to unpaired cysteines (positions 8 and 71). Alpha 2-Macroglobulin (alpha 2-M) has internal thioester bonds between cysteine and glutamate residues. Free SH groups may be generated at these alpha 2M residues through the action of proteinases, amines such as methylamine, or at a slow rate, by H2O ("aging" of alpha 2M). Thus, the possibility that IL-1 beta forms a disulfide bond with alpha 2M was investigated. 125I-labeled human rIL-1 beta (15 kDa) was incubated with fresh normal human serum or with purified alpha 2M, treated or not with methylamine. The mixtures were submitted to nondenaturing and denaturing polyacrylamide gel electrophoresis (PAGE) followed by autoradiography. IL-1 beta bound to commercially purified "aged" alpha 2M and to alpha 2M in methylamine-treated serum but not to native serum alpha 2M. It did not bind detectably to any other serum proteins. The addition of D-penicillamine (D-pen) during the reaction of [125I]rIL-1 beta with serum or purified alpha 2M blocked the covalent binding of rIL-1 beta to alpha 2M. [125I]rIL-1 beta was removed from alpha 2M by 2-mercaptoethanol in SDS. Thus, disulfide bonds were formed between the free SH groups on [125I]rIL-1 beta and those resulting from the cleavage of the internal thioester bonds of alpha 2M. "Cold" rIL-1 beta and a Cys71----Ser71 rIL-1 beta mutant effectively competed with [125I]rIL.1 beta for binding sites on alpha 2M. When complexes of rIL-1 beta or the mutant rIL-1 beta and alpha 2M were subjected to nonreducing SDS-PAGE and subsequent Western blot analysis, the rIL-1 beta molecules were found to be present in the alpha 2M bands in a dose-dependent manner. rIL-1 beta attached to alpha 2M in the presence or absence of D-pen showed similar biological activity in the mouse thymocyte-assay. Thus, rIL-1 beta attached noncovalently to alpha 2M is biologically active. The lack of inhibition of rIL-1 beta activity by binding to methylamine-treated alpha 2M in the absence of D-pen suggests, but does not prove, that the covalently bound rIL-1 beta is also active. We concluded that human rIL-1 beta binds to alpha 2M through the Cys at position 8 and that D-pen inhibits this binding. We speculate that this inhibitory effect may contribute to the therapeutic benefits of D-pen in patients with rheumatoid arthritis.

Is proximal pancreatoduodenectomy with pyloric preservation superior to total pancreatectomy?

The records of all patients who underwent pylorus-preserving pancreatic resection (29 subtotal and 4 total pancreatectomies) during a 10-year period at the Mayo Clinic were reviewed. Thirty-day operative mortality was 6%. Early postoperative morbidity occurred in 45% of patients and necessitated reoperation in four patients. One patient had a hemorrhage from a marginal ulcer in the early postoperative period. The incidence of late postoperative morbidity was 18%. Marginal ulcers developed in the late postoperative period in three additional patients, for an overall incidence of 13%. One patient underwent vagotomy and pyloroplasty because of intractable bleeding 2 years after initial operation. The 29 patients who underwent pylorus-preserving pancreatoduodenectomy (PPW) were compared (retrospectively) with 200 patients who had undergone standard pancreatoduodenectomy (Whipple operation) during the same 10-year period. The overall incidences of marginal ulcer were 10% in the PPW group and 5% in the Whipple group; the incidences of delayed gastric emptying were similar in these groups. We believe that caution is warranted in the use of PPW, as yet an unproved procedure.

Chondrosarcoma of the chest wall: factors affecting survival.

The cases of 96 patients (55 male and 41 female) with primary chondrosarcoma of the chest wall were reviewed. Ages ranged from 17 to 78 years (median, 53.5 years). The tumor involved the rib in 78 patients and the sternum in 18. Seventy-two patients had treatment at the Mayo Clinic, 28 by wide resection, 25 by local excision, and 19 by palliative excision. There was 1 operative death. Follow-up ranged from 1 to 46 years. Recurrent chondrosarcoma developed in 37 patients. All had local recurrence, and 14 also had metastases. Within 10 years, recurrence had developed in 50% of patients who had local excision and in 17% of patients who had wide resection. Ten-year chondrosarcoma survival (Kaplan-Meier) for patients treated by wide resection was 96%; by local excision, 65%; and by palliative excision, 14% (p less than 0.0001). Tumor grade, tumor diameter, tumor location, and date of operation all had a significant influence on survival. This report documents the natural history of chest wall chondrosarcoma and demonstrates that early wide resection is the treatment of choice.

Colorectal lung metastases: results of surgical excision.

Between 1960 and 1988, 139 consecutive patients underwent pulmonary resection for metastatic colorectal carcinoma. Median interval between colon resection and lung resection was 34 months. Ninety-eight patients (70.5%) had a solitary metastasis. Wedge excision was performed in 68 patients, lobectomy in 53, lobectomy plus wedge excision in 9, bilobectomy in 4, and pneumonectomy in 5. Operative mortality was 1.4%. Localized extrapulmonary colorectal cancer was also resected in 20 patients. Median follow-up was 7 years (range 1 to 20.4 years). Overall 5- and 20-year survival was 30.5% and 16.2%, respectively. Five-year survival for patients with solitary metastasis was 36.9%, as compared with 19.3% for those with two metastases (p less than 0.05) and 7.7% for those with more than two (p less than 0.01). Patients with normal carcino-embryonic antigen had a 5-year survival of 46.8% versus 16.0% for patients with increased levels (p less than 0.01). Five-year survival for patients with resected extrapulmonary disease was 30.0% versus 30.7% for those without extrapulmonary cancer (p = not significant). Repeat thoracotomy for recurrent metastases was done in 19 patients. Five-year survival after the second lung resection was 30.2%. We conclude that resection of colorectal lung metastases is safe and effective, that resectable extrapulmonary disease does not necessarily contraindicate pulmonary resection, and that repeat thoracotomy is warranted in selected patients with recurrent colorectal lung metastases.

Influence of complete revascularization on chronic mesenteric ischemia.

Complete revascularization for chronic intestinal ischemia is controversial. Fifty-eight patients (119 arteries) underwent mesenteric revascularization between 1981 and 1988. There were 46 women and 12 men (mean age: 63 years). Sixty percent of patients had three-vessel disease. Twenty-one patients underwent concomitant aortic reconstruction. Operative mortality was 10%. Four of the six deaths occurred in patients undergoing aortic surgery. Late graft failure occurred in five patients (10%). Five-year survival for patients with three-vessel involvement who underwent three-vessel repair was 73%, compared with 57% for two-vessel repair and 0% for one-vessel repair (p = NS). Similarly, graft patency in patients with three-vessel disease was highest in those patients who had complete revascularization (90%, 54%, and 0%, respectively) (p = NS). We conclude that increased graft patency and survival in patients with three-vessel disease was most frequent with complete revascularization. Diseased inferior mesenteric arteries should be repaired if feasible. Concomitant aortic operations should be avoided if possible.

Meeting the needs of the teen-age pregnant student: an in-school program that works.

The drop-out rate for pregnant students in the York (Pennsylvania) City School District is dramatically lower than the national average because the district recognized the need for meeting the unique problems of the pregnant student. In York, as in the rest of the nation, teen-age pregnancy was on the increase. Administrators of the district realized that a separately housed alternative education program would be too costly. In January 1979, the authors designed and implemented an in-school program called "Changing Roles." Five years later, that program has become an important factor in keeping the majority of pregnant students in school, at the same time, providing the girls the special information they need. In the 1982-83 school year, only 9.5% of the pregnant students dropped out of York City schools. This rate is far below the national drop-out rate of 80% to 90%.

PIP: Approximately 1 million US teenage girls become pregnant each year which usually means the end of their education and the beginning of a bleak future; in order to deal with this problem, York (Pennsylvania) City School District established a "Changing Roles" program in which teenagers were taught some basic pregnancy training. Because of this, the overall drop out rate decreased significantly in the 1982-1983 school year and also because the district recognized that it cost them $10,000 a year to provide home instruction for pregnant teens. The objectives of this program are to: 1) reduce the high school drop out rate, 2) deliver comprehensive prenatal education, and 3) improve the health of teenage mothers and their children. To keep costs to a minimum and to involve the community in the program, physicians, PTA members, and other local agencies participate in the program by encouraging young teens to attend the special classes. The savings to the community in terms of better educated mothers, and happier, healthier families is enormous. Compared to the high national drop out rate for pregnant teens of 80% to 90%, York schools maintain a 9.5% drop out rate for their pregnant students. This is due to the program's acceptance by faculty, students, and the community, and because on-going evaluation helps to improve the effectiveness of the program.

Cloning and chromosomal localization of the human cytoskeletal alpha-actinin gene reveals linkage to the beta-spectrin gene.

We report the cloning and characterization of a full-length cDNA encoding the human cytoskeletal isoform of alpha-actinin (alpha A), a ubiquitous actin-binding protein that shares structural homology with spectrin and dystrophin. The gene encodes 891 amino acids with 96%-98% sequence identity at the amino acid level to chicken nonskeletal muscle alpha A. Transient expression in COS cells produces a protein of approximately 104 kD that comigrates on SDS-PAGE with native alpha A. This alpha A gene is localized to chromosome 14q22-q24 by somatic cell hybrid and in situ hybridization analyses. Pulsed-field gel analysis of human genomic DNA revealed identically sized fragments when cDNA probes for alpha A and erythroid beta-spectrin were used; the latter gene has been previously localized to chromosome 14, band q22. These observations indicate that the genes for cytoskeletal alpha A and beta-spectrin are, in all likelihood, closely physically linked and that, in accordance with their similar structural features, they arose by partial duplication of an ancestral gene.

Spoken and written English errors of postsecondary students with severe hearing impairment.

This investigation compared the spoken and written English errors of 20 hearing-impaired postsecondary students with intelligible speech and poor English language. Error categories used to assess the language samples were function, content, and structure. Spoken and written performances were distinguished only by a greater number of function word errors in writing samples. A trend toward greater complexity in writing was also found. Implications for instruction are discussed.

Finite element models for arterial wall mechanics.

Arterial wall mechanics has been studied for nearly 200 years. This subject is of importance if we are to gain a fundamental understanding of this complex biological structure, as well as information needed to design prosthetics. Biomechanical arterial models continue to play an important role in the study of atherosclerosis, a disease of the arterial wall that is the chief cause of mortality and morbidity in the United States and the Western World. Over the past 20 years, the finite element model (FEM) has been used in a variety of ways to simulate the structural response of large arteries. Our purpose is to summarize the uses of FEMs in arterial mechanics. We will also indicate directions for future research in this area. A specialized FEM was described in the literature for the study of transport in the arterial wall, however the convection was not directly linked to arterial wall mechanics. In this paper special attention will be given to the development of FEMs based on the poroelastic view of arterial tissues which couple wall deformation, free tissue fluid motion, and associated transport phenomena in the arterial wall. In the future such models should provide fundamental quantitative information relating arterial wall mechanics and transport which may lead to a better understanding of both normal arterial physiology and atherogenesis.

Recent trends in the diagnosis and management of chronic intestinal ischemia.

This paper reviews the operative management over the past 27 years of 102 patients with chronic mesenteric ischemia, and summarizes recent clinical trends and ongoing research in this area. The most important trends in the diagnosis and management of chronic intestinal ischemia include: (1) increasing use of duplex ultrasound scanning in the initial evaluation of patients with possible intestinal angina; (2) rapidly evolving noninvasive clinical tests to assess mucosal perfusion (reflectance spectrophotometry, laser Doppler flow analysis, and tonometry); and (3) preferential use of antegrade mesenteric grafts or transaortic endarterectomy for mesenteric atherosclerotic occlusive disease. Surgical revascularization continues to provide excellent early relief of symptoms (93%) and a low late recurrence rate (10%). New noninvasive diagnostic tests for chronic intestinal ischemia and excellent results of surgical revascularization support a continued aggressive approach to the early recognition and treatment of patients with chronic intestinal angina. With the aging population, we anticipate that the number of patients with chronic intestinal ischemia will increase.

Identification and determination of material properties for porohyperelastic analysis of large arteries.

A "porohyperelastic" (PHE) material model is described and the theoretical framework presented that allows identification of the necessary material properties functions for soft arterial tissues. A generalized Fung form is proposed for the PHE constitutive law in which the two fundamental Lagrangian material properties are the effective strain energy density function, W(e), and the hydraulic permeability, kij. The PHE model is based on isotropic forms using W(e) = Ue (phi) = 1/2C0(e phi - 1) and the radial component of permeability, kRR = kRR(phi), with phi = C1'(I1 - 3) + C2'(I2 - 3) + K'(J - 1)2. The methods for determination of these material properties are illustrated using experimental data from in situ rabbit aortas. Three experiments are described to determine parameters in Ue and kRR for the intima and media of the aortas, i.e., (1) undrained tests to determine C0, C1', and C2'; (2) drained tests to determine K'; and (3) steady-state pressurization tests of intact and de-endothelialized vessels to determine intimal and medial permeability (adventitia removed in these models). Data-reduction procedures are presented that allow determination of kRR for the intima and media and Ue for the media using experimental data. The effectiveness and accuracy of these procedures are studied using input "data" from finite element models generated with the ABAQUS program. The isotropic theory and data-reduction methods give good approximations for the PHE properties of in situ aortas. These methods can be extended to include arterial tissue remodeling and anisotropic behavior when appropriate experimental data are available.

Is percutaneous coronary angioplasty less expensive than bypass surgery?

Percutaneous transluminal coronary angioplasty is widely considered to be an acceptable and less expensive alternative to bypass surgery in carefully selected patients. We compared expenditures related to cardiac care for 79 unselected patients undergoing coronary angioplasty with expenditures for 89 unselected patients undergoing elective coronary bypass surgery without a previous attempt at angioplasty. All the patients had single-vessel disease. The mean aggregate one-year monetary outlay was 15 per cent lower in the angioplasty group than in the bypass-surgery group. A major component of the expense of angioplasty was the treatment of restenosis in the 33 per cent of patients in this group in whom this late complication occurred. We conclude that percutaneous transluminal coronary angioplasty has potential for reducing expenditures for cardiac revascularization and that a further reduction may be obtainable when the rates of restenosis are improved.

Feline muscular dystrophy with dystrophin deficiency.

This is the first description of a dystrophin-deficient muscular dystrophy in domestic cats. The disorder appears to be of X-linked inheritance because it affected both males of a litter of four kittens. Immunoblotting and immunofluorescent detection of dystrophin showed dystrophin present in control cat muscle but no detectable dystrophin in either affected cat. The feline muscular dystrophy was progressive and histopathologically resembled human Duchenne/Becker muscular dystrophy except for the lack of fat infiltration and the presence of prominent hypertrophy of both muscle fibers and muscles groups in the feline disorder.