Persistent immunity and survival after immunization with a HER2/neu (HER2) vaccine

3010

Background: Our initial vaccine studies showed that optimally treated breast cancer patients can be immunized against HER2 during active immunization. The majority of patients developed T-cell immunity to HER2 peptides and protein and also epitope spreading (ES). The goal of this study was to determine if patients previously immunized with a HER2 vaccine had persistent immunity years after active immunization and to assess their clinical outcome in terms of overall survival (OS). Methods: Subjects eligible for this IRB-approved long term follow-up (LTFU) study: (1) had HER2+ breast cancer and were immunized between 1996–1999 in a phase I HER2 peptide vaccine trial, (2) were at least 1 year out from their last vaccine, and (3) if donating blood samples could not be receiving chemotherapy. 52 patients (37 stage IV, 15 stage III) were identified and 21/52 patients (12 stage IV, 9 stage III) were determined to be living. All 21 subjects were contacted by letter and sent a LTFU Questionnaire. OS was defined as the time between date of vaccine study entry and death or last follow-up and was estimated using the Kaplan-Meier method. Cox proportional hazards were used to determine associations between OS and known clinical and vaccine-related immunologic factors; analyses included all 52 subjects. Long-term T-cell immunity was evaluated using IFN-γ ELISPOT assay. Results: Median follow-up time for the 21 patients still alive was 112 months (range, 104–126 months). Blood samples were collected in 10/21 subjects and 6/8 (75%) evaluble patients had persistent T-cell immunity to immunizing HER2 peptides; and 7/8 patients (88%) had T-cell immunity specific for HER2 protein and peptides not contained in their immunizing mix (defined as ES). In multivariate analysis, number of chemotherapy regimens prior to vaccination (HR=5.7 (CI 95%, 1.5–23; p=<0.001)), and development of ES after HER2 vaccination (HR=0.34 (CI 95%, 0.12–1.0; p=0.05)) were independent predictors of OS. Median OS for 33 subjects who developed ES was 84 months vs 25 months for 16 subjects who did not develop ES. Conclusions: HER2-specific T-cell immunity elicited with active immunization is durable years after vaccination has ended and the generation of ES is an independent predictor of OS.

No significant financial relationships to disclose.

Statistical comparison of residential soil concentrations of PCDDs, PCDFs, and PCBs from two communities in Michigan

The University of Michigan dioxin exposure study was undertaken to address concerns that the industrial discharge of dioxin-like compounds in the Midland, MI area had resulted in contamination of soils in the Tittabawassee River floodplain and downwind of the incinerator. The study was designed in a rigorously statistical manner comprising soil measurements of 29 polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) from 766 residential properties, selected probabilistically, in the Midland area and in Jackson and Calhoun Counties (Michigan) as a background comparison. A statistical comparison determined that the geometric mean toxic equivalent (TEQ) levels in samples from the target populations were statistically significantly above background. In addition, the probabilities of being above the 75th and 95th percentiles of background were also greater. Congener contributions to the TEQ were dominated by 2,3,4,7,8-PeCDF and 2,3,7,8-TCDF in the floodplain and by 2,3,7,8-TCDD in the incinerator plume. However, PCB 126 was the top congener contributing to the background TEQ. On the basis of statistical inference to the total population, it was estimated that about 36% of the properties in the floodplain and incinerator plume have at least one soil sample over the Michigan Department of Environmental Quality's soil direct contact criterion of 90 pg/g TEQ.

In situ study of insulin aggregation induced by water-organic solvent interface

PURPOSE

The aim of this study was to assess insulin stability by monitoring in situ time-course of insulin aggregation induced by a water-organic solvent (o/w) interface that occurs during the microencapsulation process.

METHODS

Insulin aggregation at a simple o/w interface was monitored spectrophotometrically by detecting the percentage of turbidity changes (%T) at 350 nm. The effects of protein concentration and agitation and the presence of poly (lactic-co-glycolic acid) (PLGA) in methylene chloride (MC) on insulin aggregation were observed. For the 0.72 mg/ml insulin in phosphate-buffered saline (PBS), the effect of nonionic (dodecyl maltoside [DDM]) and anionic (sodium dodecyl sulfate [SDS]) surfactant in PBS were also evaluated at various protein/surfactant mol ratios. The conformation of insulin protected by a 10-fold molar excess of SDS recovered after 1 h of contact with MC was evaluated via circular dichroism (CD) spectroscopy.

RESULTS

A typical turbidity-time profile was represented by a sigmoidal curve. Greater change in %T was observed with increasing insulin concentration, in the presence of PLGA in MC and in the presence of agitation. DDM failed to delay insulin aggregation at all ratios used, whereas a less than 10% change in %T was observed in 1 h when a 10- - approximately 20-fold excess of SDS was used. CD spectra indicated that the presence of insulin in SDS after 1 h of contact with MC qualitatively retained its secondary structure integrity.

CONCLUSIONS

An experimental method was designed for an in situ assessment of protein stability at the o/w interface.

The Swedish Knee Arthroplasty Register 1975-1997: an update with special emphasis on 41,223 knees operated on in 1988-1997

From 1975, when the Swedish Knee Arthroplasty Register (SKAR) started, until the end of 1997, 57,533 primary arthroplasties and revisions have been registered. Recently, the register underwent a comprehensive validation and update regarding revisions. We now report on general demographic and epidemiological data for the whole period and on the survivorship of arthroplasties performed in Sweden during 1988-1997. During this 10-year period, 41,223 primary knee arthroplasties were performed on 34,877 patients. We found, as in our earlier reports, that survivorship was affected by patient-, time-, implant- and method-related factors but, apart from an overall higher cumulative revision rate, general conclusions reported from the register in recent years appeared to be unaffected.

92nd AACR. Immunologic approaches to the treatment and prevention of cancer

Tumor immunology is advancing at a rapid rate and an increased number of investigators are providing important contributions to the field. Greater than 250 abstracts dealing directly with tumor immunology were presented at the 92nd Annual Meeting of the American Association of Cancer Research in New Orleans, LA, USA. All facets of tumor immunology were represented by excellent abstracts addressing dendritic cells, mechanisms of effective tumor immunity, immune defects in cancer patients, tumor antigens, cancer vaccines, and cancer immunotherapies.

The routine of surgical management reduces failure after unicompartmental knee arthroplasty

A total of 10,474 unicompartmental knee arthroplasties was performed for medial osteoarthritis in Sweden between 1986 and 1995. We sought to establish whether the number of operations performed in an orthopaedic unit affected the incidence of revision. Three different implants were analysed: one with a high revision rate, known to have unfavourable mechanical and design properties; a prosthesis which is technically demanding with a known increased rate of revision; and the most commonly used unicompartmental device. Most of the units performed relatively few unicompartmental knee arthroplasties per year and there was an association between the mean number carried out and the risk of later revision. The effect of the mean number of operations per year on the risk of revision varied. The technically demanding implant was most affected, that most commonly used less so, and the outcome of the unfavourable design was not influenced by the number of operations performed. For unicompartmental arthroplasty, the long-term results are related to the number performed by the unit, probably expressing the standards of management in selecting the patients and performing the operation.

The routine of surgical management reduces failure after unicompartmental knee arthroplasty

A total of 10474 unicompartmental knee arthroplasties was performed for medial osteoarthritis in Sweden between 1986 and 1995. We sought to establish whether the number of operations performed in an orthopaedic unit affected the incidence of revision. Three different implants were analysed: one with a high revision rate, known to have unfavourable mechanical and design properties; a prosthesis which is technically demanding with a known increased rate of revision; and the most commonly used unicompartmental device.

Most of the units performed relatively few unicompartmental knee arthroplasties per year and there was an association between the mean number carried out and the risk of later revision. The effect of the mean number of operations per year on the risk of revision varied. The technically demanding implant was most affected, that most commonly used less so, and the outcome of the unfavourable design was not influenced by the number of operations performed.

For unicompartmental arthroplasty, the long-term results are related to the number performed by the unit, probably expressing the standards of management in selecting the patients and performing the operation.

Past incidence and future demand for knee arthroplasty in Sweden: a report from the Swedish Knee Arthroplasty Register regarding the effect of past and future population changes on the number of arthroplasties performed

By combining data from the Swedish Knee Arthroplasty Register and Swedish census registers we have calculated the past age-specific incidence of primary knee arthroplasties and predicted the demand. During the last 20 years, osteoarthrosis has accounted for the largest increase in number of knee arthroplasties while operations for rheumatoid arthritis remained constant. The mean yearly number of operations between the periods 1976-1980 and 1996-1997 increased more than five-fold, while only 6% of that increase could be explained by changes in the age-profile of the population. Most operations were performed on persons of 65 years and older who also had the largest increase in incidence. By using the incidences for 1996 and 1997 and taking into account the expected future changes in the age profile of the Swedish population, we estimate that, in the absence of an effective preventive treatment, the number of knee arthroplasties will increase by at least one third until 2030.

Patient satisfaction after knee arthroplasty: a report on 27,372 knees operated on between 1981 and 1995 in Sweden

During a validation process of the Swedish Knee Arthroplasty Register (SKAR), living registered patients were sent a questionnaire to ask if they had been reoperated on. This gave an opportunity to pose a simple four-point question with respect to patient satisfaction which 95% of patients answered. We analyzed the answers of patients operated on between 1981 and 1995 and found that only 8% of the patients were dissatisfied regarding their knee arthroplasty 2-17 years postoperatively. The satisfaction rate was constant, regardless of when the operation had been performed during the 15-year period. The proportion of satisfied patients was affected by the preoperative diagnosis, patients operated on for a long-standing disease more often being satisfied than those with a short disease-duration. There was no difference in proportions of satisfied patients, whether they had primarily been operated on with a total knee arthroplasty (TKA) or a medial unicompartmental arthroplasty (UKA). For TKAs performed with primary patellar resurfacing, there was a higher ratio of satisfied patients than for TKAs not resurfaced, but this increased ratio diminished with time passed since the primary operation. Unrevised knees had a higher proportion of satisfied patients than knees that had been subject to revision, and among patients revised for medial UKA, the proportion of satisfied patients was higher than among patients revised for TKA. We conclude that satisfaction after knee arthroplasty is stable and long-lasting in unrevised cases and that even after revision most patients are satisfied.

Validation of the Swedish Knee Arthroplasty Register: a postal survey regarding 30,376 knees operated on between 1975 and 1995

The Swedish Knee Arthroplasty Register is dependent on the participating clinics regarding accuracy of information. As the register is prospective, and since revision is used as the endpoint in survival analyses, it is important that all revisions of registered primary arthroplasties are reported. To validate the register, we sent a questionnaire to all living patients with 30,796 knees registered as having been operated on from 1975-1995. Of living patients, 99% could be located and 93% answered. We found that one fifth of the revisions had not been reported and that relatively fewer revisions were lost to follow-up during the first decade of the register than in the following years. To investigate whether the Patient Administrative System (PAS), a database based on ICD coding and run by the Swedish health authorities, could be used to locate missing revisions found by the postal survey, we compared this database with the Swedish Knee Arthroplasty Register. 84% of the missing revisions revealed by the postal survey were found by using this method. Hence after the survey and the use of the PAS to find unreported revisions in deceased and non-responding patients, we estimate that 94% of all revisions are accounted for. Apart from a generally higher cumulative revision rate, conclusions reported from the Register in recent years regarding survivorship seem to be unaffected by the underreporting.

Use of unicompartmental instead of tricompartmental prostheses for unicompartmental arthrosis in the knee is a cost-effective alternative. 15,437 primary tricompartmental prostheses were compared with 10,624 primary medial or lateral unicompartmental prostheses

Unicompartmental knee arthroplasty (UKA) is known to have a higher risk of revision than tricompartmental arthroplasty (TKA), while UKA implants are generally less expensive than TKA implants. We estimated the costs of implants and hospital stay of both procedures and related the cost difference at primary operation to the difference in number of revisions to be expected. We compared 15,437 primary TKAs and 10,624 primary medial or lateral UKAs. The operations were all done on patients with arthrosis during 1985-1995. By matching patients in the Swedish Patient Administration System with the Swedish National Knee Arthroplasty Register, the groups could be compared regarding the length of the hospital stay. The cumulative revision rate (CRR) and the relative risk of revision were calculated with survival statistics, as well as the risk of a second revision and the risk of infection. The weighted mean cost of the commonest implants in each group was used as an estimate of the implant cost. We found that the TKA patients were, on average, 2 years older at operation and had a lower CRR than the UKA patients-i.e., 10-year CRR of 12% and 16%, respectively. After adjusting for age, gender and year of operation, UKA patients were found to have a 2-day shorter hospital stay and fewer serious complications than TKA patients. The mean estimated cost of a unicompartmental implant was 57% of that of a tricompartmental implant. We conclude, that by using UKA instead of TKA in appropriate patients, money can be saved, even after taking into account the increased number of revisions to be expected.

Revision of unicompartmental knee arthroplasty: outcome in 1,135 cases from the Swedish Knee Arthroplasty study

From 1975 through 1995, 45,025 knee arthroplasties were recorded in the prospective Swedish Knee Arthroplasty study. By the end of 1995, 1,135 of 14,772 primary unicompartmental knee arthroplasties (UKA) for localized, mainly medial arthrosis had been revised. The Marmor/Richards and St. Georg sledge/Endo-Link prostheses were used in 65%. Mean age at revision was 72 (71) years. 232 revisions were performed as an exchange UKA (partial in 97) and 750 as a total knee arthroplasty (TKA). 153 were revised by other modes. In medial UKA, the indication for revision was component loosening in 45% and joint degeneration in 25% and in lateral UKA, the corresponding figures were 31% and 35%, respectively. In 94 cases, unicompartmental components were added to the initially untreated compartment, in 14 with partial exchange of a component. The CRRR was estimated using survival statistics. After only 5 years, the risk of having a second revision was more than three times higher for failed UKAs revised to a new UKA (cumulative rerevision rate (CRRR 26%) than for those revised to a TKA (CRRR 7%). This difference remained, even if those revised before 1985, when modern operating technique was introduced, were excluded (CRRR 31% and 5%, respectively). UKA is a safe primary procedure, when performed with well-designed components and modern surgical technique. It gives documented good patient satisfaction, range of motion, pain relief and relatively few serious complications. However, once failed, the knee should be revised to a TKA. This applies to most modes of failure. Not even joint degeneration of the unoperated compartment can be safely treated by adding contralateral components; CRRR after this procedure was 17%, while it was 7% when converted to a TKA.

Knee arthroplasty in rheumatoid arthritis. A report from the Swedish Knee Arthroplasty Register on 4,381 primary operations 1985-1995

The Swedish Knee Arthroplasty Register has data on 4,381 primary operations performed 1985-1995 for rheumatoid arthritis. Of these, 192 were performed with unicompartmental prostheses and 4143 with tricompartmental. 77% were women and the mean age was 66 years. There were 126 first, 20 second, and 1 third revision in tricompartmental arthroplasties, mainly for loosening, infection and patellar problems. There were 38 first, 3 second, and 1 third revision in unicompartmental arthroplasties, mainly for progression of RA and loosening. Cumulative revision rates (Kaplan-Meier) were calculated. Tricompartmental knees had a 10-year cumulative revision rate of 5% and uni-knees 25%. Patients treated before 1990, men and patients younger than 55 had higher revision rates than patients treated after 1990, women and older patients, respectively. Cemented tibial components resulted in lower revision rates than uncemented ones. There was no significant difference in revision rates between patellar replaced and unreplaced knees or between the 9 commonest implant types.

Oxford meniscal bearing knee versus the Marmor knee in unicompartmental arthroplasty for arthrosis. A Swedish multicenter survival study

In the Swedish Knee Arthroplasty Study, all 699 Oxford meniscal bearing cemented unicompartmental prostheses (Biomet, Bridgend, UK) were identified and analyzed regarding failure pattern and compared with all Marmor prostheses (Smith & Nephew Richards, Orthez, France) and with a time-, age-, and sex-matched subset of Marmor prostheses using survival statistics expressed as cumulative revision rates. After 1 year there was already a higher rate, and after 6 years the rate of the Oxford group was more than twice that of the Marmor group. There were 50 revisions in the Oxford group: dislocating meniscus in 16, loosening of the femoral component in 6, tibial component in 4, both components in 4, contralateral arthrosis in 10, infection in 4, and technical failure with instability, pain, and/or impingement of the meniscal bearing anterior in the femoral condyle in 6. It is still unclear if the design with the sliding menisci will, in the long turn, reduce wear and loosening, thereby compensating for the initially inferior results. It is recommended that until this question is clarified, the Oxford knee should be used on a limited scale for long-term comparative studies only.

Accurate determination of skin flux from flow-through diffusion cell data

PURPOSE

The goal of this investigation was to demonstrate whether the intrinsic flux of a drug diffusing across a membrane mounted in a flow-through diffusion cell may be accurately and easily determined by accounting for the accumulation in the receiver chamber.

METHODS

Mathematical modeling, applied to transdermal diffusion, was used to calculate receiver concentration data for single layer and bilayer membranes. The data were interpreted using two apparent flux values, Japp1 and Japp2. Japp1 has been used extensively in the literature, but did not account for accumulation in the receiver. Japp2 did take the accumulation into consideration.

RESULTS

The results confirm that, generally, Japp1 values were not accurate estimates of the intrinsic flux. Japp2 values were significantly more accurate, especially prior to the maximum in receiver concentration.

CONCLUSIONS

Japp2 was an accurate measurement of intrinsic flux over the entire experimental time period, except at time zero. It was more accurate because it accounted for solute accumulation in the receiver compartment. The accuracy of the Japp2 approximation was practically independent of receiver volume, flow rate and donor volume. For very slowly permeating drugs, or a very small receiver volume combined with a high flow rate, the Japp1 estimate accurately reflected the intrinsic flux. Early time data were required to properly account for accumulation in the receiver cell. If such data were not available, the inverse Laplace method of determining intrinsic flux was preferable to the Japp2 calculation.

Intraoperative monitoring of ulnar nerve function during replacement of the rheumatoid elbow via the lateral approach

Neurography of the ulnar nerve was performed pre-, intra- and postoperatively in 8 arms of 7 patients with rheumatoid arthritis operated on with total elbow replacement via the lateral approach. Ulnar nerve decompression was performed in 4 elbows before implantation. A reduction in the amplitude of compound muscle action potential (CMAP) recorded from the abductor digiti minimi on stimulation of the ulnar nerve in the axilla, was observed during elbow dislocation at surgery in all patients, in 5 cases transiently and in 3 cases until the end of surgery. The ulnar nerve had been decompressed in all patients with lasting amplitude reduction. One of them had a mild sensory ulnar nerve palsy, while the other 2 had normal nerve function at the postoperative clinical examination. All 3 had a reduction in the amplitude of compound sensory nerve action potential (SNAP) and 2 of them also in CMAP amplitude at the postoperative neurographic examination. In patients with transient reduction during surgery, the CMAP amplitude quickly normalized on relocation of the elbow and both the SNAP and the CMAP were preserved at the postoperative neurographic examination. The authors conclude that dislocation of the laterally approached elbow carries a risk of ulnar nerve injury, which is not prevented by decompression of the ulnar nerve, but frequent relocation of the elbow during surgery seems important. It is suggested that the ulnar nerve should not be decompressed routinely, and that the dislocated elbow should be frequently relocated.

Fourier transform infrared spectroscopy investigations of protein structure

Infrared spectroscopy can provide insight into protein structure. This technique is sensitive to the backbone amide arrangement of peptide and protein molecules. In many cases, complementary as well as more expansive information is obtained as opposed to information obtained by other methods that examine the molecule's environmental surroundings, require molecular probes, or perhaps cannot investigate the molecule in its native environment. The foundation for spectroscopic differences between the various secondary structures arises not only from geometrical differences and hydrogen bond variations but also transition dipole coupling between neighboring oscillators. Theoretical predictions of protein spectra have been made using normal mode analysis and combined with experimental data. At present the amide I band has provided the most insight into secondary structure. Even more convincing results are obtained when both H2O and D2O are used as solvents. Recent advances in computerized technology and mathematical techniques have expanded the potential contributions of infrared spectroscopy in the area of protein structural determination. However, the limitations of resolution enhancement and curve-fitting techniques must be taken into consideration. The parameters must be carefully and optimally chosen and evaluated on a case-by-case basis. The subjectivity of these techniques makes a thorough understanding of the algorithms necessary, especially those commercially available. Infrared spectroscopy continues to provide insight into protein and peptide structures under biologically relevant conditions that enable the structure-function relationships for such molecules to be better understood.

Enhanced permeation of polar compounds through human epidermis. I. Permeability and membrane structural changes in the presence of short chain alcohols

The influence of alcohol chain length on polar compound permeation in human skin was investigated to further understand alcohol-enhanced permeation mechanisms. Both thermodynamic and kinetic variables associated with the enhanced permeation of mannitol were ascertained in the presence of high concentrations of short chain alcohols. Permeation of mannitol through human epidermis in the presence of 75% (v/v) alcohol-saline mixtures was determined in symmetric, side-by-side diffusion cells at 32 degrees C. Permeability coefficients increased with increasing alcohol chain length (iso-propanol > ethanol > methanol). Uptake of mannitol into the epidermal tissue increased in the presence of the short chain alcohols, but was independent of alcohol chain length. In addition, mannitol solubility decreased in the presence of the short chain alcohols, but again was independent of alcohol chain length. Therefore, increased mannitol permeability with increasing alcohol chain length could not be attributed to thermodynamic variables. Changes in the amount and conformation of stratum corneum lipids and proteins were determined by Fourier transform infrared (FTIR) spectroscopy. Stratum corneum lipid conformation and mobility was not significantly altered in the presence of the short chain alcohols. However, decreased absorbance of the alkyl chain suggested lipid extraction, which increased with increasing alcohol chain length. Stratum corneum protein conformation was altered in the presence of the short chain alcohols. Decreased infrared absorbance of the Amide I band maximum suggested extraction of stratum corneum proteins, which increased with increased alcohol chain length. These results suggest a correlation between enhanced permeation and extraction of lipids as well as proteins from human skin in the presence of 75% (v/v) aqueous alcohol solutions.

The Swedish knee arthroplasty register. A nation-wide study of 30,003 knees 1976-1992

1976 through 1992, 30,003 primary knee arthroplasties and their revisions have been recorded in a nation-wide Swedish study. We report on the structure of the register, demographic data and survivorship. We found that operations for osteoarthrosis (OA) counted for the increase in number of arthroplasties in contrast to rheumatoid arthritis (RA), where the number had slightly declined. For primary operations, the total knee prostheses have practically eliminated other types in RA and are steadily gaining popularity in OA at the expense of the unicompartmental prostheses. Total knee replacements showed gradually improving survival even in unchanged designs while the unicompartmental prostheses don't, partly because of newly introduced inferior designs. We also found that failed unicompartmental prostheses were best replaced with a tricompartmental prosthesis and that a total revision was to be preferred when a tricompartmental tibial component failed. The risk of the most devastating complications, e.g., infection, leading to extraction of the prosthesis or arthrodesis has decreased considerably also in the last years.

Fracture subluxation of proximal interphalangeal joint treated by palmar plate advancement

A modified technique of palmar plate advancement (PPA) was used to treat certain patients, most with failed previous treatment, with fracture subluxation of the proximal interphalangeal joint. The modification of the original technique consisted of using two sutures to attach the palmar plate and tying them deep to the skin on the dorsum. This allowed consistent maintenance of reduction, and there were no infections. The results of 11 of 23 patients who were treated with this technique and followed from 2 to 9 years postoperatively are reported. The indications for PPA in this injury are discussed.

Enhanced permeation and stratum corneum structural alterations in the presence of dithiothreitol

Stratum corneum protein biochemical and biophysical structural contributions to the barrier properties of human epidermis were determined in the presence of the reducing agent dithiothreitol (DTT). Mannitol and sucrose permeation through human epidermis in the presence of 0 to 50 mM DTT in PBS (pH 7.4) was measured in symmetric, side-by-side diffusion cells (32 degrees C). DTT enhancement ratios, KP(DTT)/KP(PBS), ranging from 1.6 to 32, were dependent on skin donor and DTT concentrations. DTT did not alter stratum corneum uptake of mannitol or sucrose nor mannitol solubility in DTT/PBS solutions. Stratum corneum biophysical structure was ascertained by FTIR in solvent replacement experiments. DTT-induced protein conformational alterations were apparent in the emergence of an Amide I band near 1615 cm-1, which is generally associated with beta-sheet-like conformers. Therefore, DTT alters stratum corneum biophysical structure through interactions with proteins. After exposure of stratum corneum protein sheets to DTT/PBS solutions, the free thiol concentration increased from < 1 nmol SH/mg protein sheet to approx. 130 nmol/mg. The enhanced permeation which increased with increasing concentrations of DTT, was associated with diffusion mechanisms involving the cornified cells of the stratum corneum. These results indicate that corneocyte protein integrity does contribute to barrier function of the skin and influences the transport of polar solutes.

Reduced failure rate in knee prosthetic surgery with improved implantation technique

From the Swedish Knee Arthroplasty project, started in 1975, types of relatively unmodified knee prostheses were chosen for analysis of time-dependent changes in the failure rate. One thousand nine hundred sixty-nine Marmor unicompartmental and 376 Total Condylar arthroplasties, all cemented, were followed until the end of 1989. The cumulative revision rates calculated with survival statistics showed a continuous improvement with time. The five-year revision rate was reduced from 11% to 5% for the Marmor prosthesis and from 10% to 2% for the Total Condylar prosthesis. This indicates that factors other than improved design are important. Such factors could include improved guide instruments, better surgical and cementing technique, influence of a learning curve, and patient selection.

Ethanol effects on the stratum corneum lipid phase behavior

The stratum corneum is considered to be the diffusional barrier of mammalian skin for water and most solutes. The intercellular lipid multilayer domains of the stratum corneum are believed to be the diffusional pathway for most lipophilic solutes. Fluidization of the lipid multilayers in the presence of ethanol is frequently conceived to result in enhanced permeation. Current investigations address the effect of ethanol on the phase behavior in terms of stratum corneum lipid alkyl chain packing, mobility and conformational order as measured by Fourier transform infrared (FTIR) spectroscopy. Phospholipid multilamellar vesicles were also studied as model systems. There appeared to be no effect of ethanol on either the solid-solid phase transition or the gel phase interchain coupling of the stratum corneum lipids. However, there was a reduction in the mobility of the alkyl chains in the presence of ethanol. Possible mechanistic relationships between the current FTIR spectroscopic results with available literature data of ethanol induced lipophilic solute penetration enhancement through the skin are discussed.

The stratum corneum lipid thermotropic phase behavior

The stratum corneum, the outermost layer of mammalian skin, is considered the least permeable skin layer to the diffusion of water and other solutes. It is generally accepted that the intercellular lipid multilayer domain is the diffusional pathway for most lipophilic solutes. Fluidization of the lipid multilayers is believed to result in the loss of barrier properties of the stratum corneum. Current investigations address the lipid thermotropic phase behavior in terms of lipid alkyl chain packing, mobility and conformational order as measured by Fourier transform infrared (FTIR) spectroscopy. A solid-solid phase transition is observed with increased alkyl chain mobility followed by a gel to liquid-crystalline phase transition near 65 degrees C. These results further elucidate the role of lipid fluidity that may contribute to the transport properties of the stratum corneum.

Talonavicular arthrodesis in the rheumatoid foot

Arthrodesis of the talonavicular joint with a cylindrical dowel was performed in 19 feet in 17 rheumatoid patients with arthritic destruction of the talonavicular joint, but without fixed hindfoot deformity. Osseous union was achieved in 12 feet, but all patients experienced pain relief and no foot showed progressive valgus deformity of the hindfoot during follow-up. Staple fixation seemed to promote osseous union. The procedure, easy to perform and requiring only 6 weeks of immobilization, may, in the absence of fixed hindfoot deformity, supersede triple arthrodesis in rheumatoid patients with hindfoot arthritis.

Duplication of distal 19q: clinical report and review

We report on a 20-month-old boy with duplication of the distal part of 19q. His karyotype is 46,XY, -22, + der(22),t(19;22)(q13.3;p11.2)mat. The propositus has multiple minor anomalies, congenital heart defects, seizures, profound psychomotor retardation, and growth impairment. These characteristics are similar to those in the other 10 reported cases of distal 19q duplication and help delineate the phenotype. A review of the literature is presented.

The infected knee arthroplasty. A 6-year follow-up of 357 cases

The incidence of deep infection after 12,118 primary knee arthroplasties performed in Sweden from October 1, 1975 through 1985 with a median follow-up of 6 years was 1.7 percent for arthrosis and 4.4 percent for rheumatoid arthritis. Risk factors for infection were large prostheses, postoperative wound-healing complications, rheumatoid arthritis, a prior deep infection, and skin infections. We have analyzed the treatment of 357 knee arthroplasties with a deep infection. Systemic antibiotics alone were primarily used in 225 knees, with healing of the infection in 44 knees, 20 of which had a functioning prosthesis at the final follow-up; the treatment did not compromise later revision surgery. Soft-tissue surgery was used in 154 knees--37 healed, 15 of which had a functioning prosthesis. Resection arthroplasty resulted in healing of the infection in 11 of 22 knees. Revision arthroplasty was performed in 107 knees, with eventual healing of the infection in 81 knees, 36 of which had a functioning prosthesis; there were no differences in the outcome of one-stage and two-stage procedures. Arthrodesis was attempted in 135 knees, with eventual healing of the infection in 120 knees and fusion in 105. Twenty-two patients were amputated. Thus, the infection healed in 315 knees (88 percent), but only 71 (20 percent) recovered with a functioning prosthesis, and 8 patients died of the infection. Attention should therefore focus on prophylactic measures directed towards the soft-tissue problems--by avoiding conflicting skin incisions, by gentle handling of the periarticular soft tissues, by avoiding the use of constrained prostheses and oversized compartmental prostheses, by letting wound healing take priority over motion in knees with compromised soft tissues, and by using prophylactic antibiotic treatment for skin ulcers until these have healed.

Percutaneous absorption enhancement of an ionic molecule by ethanol-water systems in human skin

Ethanol-water systems enhance permeation of ionic solutes through human stratum corneum. Optimum enhancement of salicylate ion permeation has been observed with ethanol volume fractions near 0.63. The mechanism of action of ethanol-water systems enhancing skin permeation was investigated by in vitro skin permeation studies combined with Fourier transform infrared spectroscopy experiments. The increased skin permeation of the ionic permeant by the ethanol-water systems may be associated with alterations involving the polar pathway. Polar pathway alterations may occur in either or both the lipid polar head and proteinaceous regions of the stratum corneum. Ion-pair formation may also contribute to increased permeation. However, the decreased permeation of salicylate ion observed at higher volume fractions of ethanol may be attributed to decreased uptake of permeant into the stratum corneum.

Poly(dimethylsiloxane)-poly(ethylene oxide)-heparin block copolymers. II: Surface characterization and in vitro assessments

Amphiphilic block copolymers containing poly(dimethylsiloxane), poly(ethylene oxide), as well as heparin-coated glass beads and tubes were evaluated for the amounts and activities of surface-immobilized heparin. Because the amphiphilic copolymer system is thermodynamically predicted to demonstrate low-energy phase enrichment on the surfaces of air-cast films, studies were also undertaken to understand the in vitro results. Solvent-cast copolymer films have a heterogeneous microphase-separated structure according to transmission electron micrographs. Wilhelmy plate contact angle analysis indicates significant surface restructuring occurs upon hydration. Attenuated total reflectance infrared spectroscopy studies of the desiccated and hydrated films at two different sampling depths show compositional heterogeneity as a function of depth, as well as near surface restructuring allowing surface enrichment of the high-energy segments following contact with water. Significant concentrations of heparin are detected on the surface of these coatings by toluidine blue assays. In addition, a portion of the surface-bound heparin maintains its original bioactivity as determined by recalcification times, thrombin times, and Factor Xa assays. These substrates were also tested for platelet adhesion and activation reactions in vitro using polymer-coated beads in rabbit platelet-rich plasma. Heparinized polymers promoted low levels of platelet adhesion and serotonin release. Surface concentrations of heparin from bioactivity assays were then correlated with platelet adhesion and the extent of platelet release to assess the efficacy of this heparin-immobilized copolymer as a blood-compatible material or coating.

Revision after osteotomy for gonarthrosis. A 10-19-year follow-up of 314 cases

During a 10-year period, 314 tibial osteotomies were performed for medial gonarthrosis. At follow-up after 10-19 years, 62 knees had been revised by arthroplasty (52 cases) or reosteotomy (10 cases). The revision rate was 54/170 in undercorrected knees and 8/144 in knees with normalization or overcorrection of the hip-knee-ankle angle. Our results confirm that tibial osteotomy for gonarthrosis requires proper indications and precise surgery. Perhaps, given another 10 years, our osteotomies will have outlived contemporary arthroplasties.

Mechanism of ethanol-enhanced estradiol permeation across human skin in vivo

The influence of ethanol on the permeation of 17 beta-estradiol (estradiol) across viable human skin in vivo was investigated with the human skin sandwich flap model. Maintaining continuous delivery of a constant concentration of the solute in phosphate-buffered saline, pH 7.4 (PBS), or mixtures of ethanol in PBS to the skin surface revealed that steady-state flux of estradiol was achieved within 30-60 min and maintained throughout 4 hr. The 10-fold decrease in in vivo flux and permeability coefficient (Kp) of tracer estradiol solutions in ethanol or ethanol solutions compared with PBS vehicle reflected the 10-fold difference in the apparent partition coefficients (Km) of estradiol from the respective vehicles into isolated human stratum corneum. Neither the stratum corneum thickness nor the diffusion coefficient of estradiol was significantly different among the vehicles tested. In vivo flux of estradiol in ethanol or ethanol solutions across viable human skin was increased with saturated solutions of estradiol. Further, in vivo flux of estradiol from vehicles such as PBS, ethanol, and ethanol mixtures, which minimally alter the rate-limiting barrier, can be successfully predicted with knowledge of only two physicochemical parameters, the estradiol concentration in the vehicle and the Km of estradiol from the vehicle into isolated human stratum corneum.

Effects of long-term hydration leading to the development of polar channels in hairless mouse stratum corneum

Dramatic increases in in vitro permeability coefficients have been observed following the long-term hydration (days) of hairless mouse skin. The effect is greatest for extremely polar or ionized solutes. Differential scanning calorimetry has been utilize in complementary studies in an attempt to assess if the altered permeability may be due to the irreversible alteration of lipid fluidity or keratin structure. The melting range of the lipid endotherms appears to be unaffected when stratum corneum is subjected to hydration conditions similar to those in the permeability experiments. Endotherms attributed to keratin appear to be altered by long-term hydration. However, no quantitative correlation was found between the keratin endotherm area and the permeabilities. The permeability data fit a model where the total permeability coefficient at a given time is the sum of the permeability coefficients associated with the lipid route and the polar route. Permeation increases with hydration time due primarily to alteration of the polar route. Based on molecular weight, no limitation of diffusion in the polar pathway was detected.

Dose-dependent enhancement effects of azone on skin permeability

In vitro permeability experiments have been combined with differential scanning calorimetry (DSC) studies in an attempt to address the dose-dependent influence of Azone on the permeability coefficients of solutes for hairless mouse stratum corneum. A spray technique was developed to deliver uniformly and quantitatively small amounts of Azone to the stratum corneum. Permeability data obtained for several model solutes of varying lipophilicity suggest lipid fluidization and polar route enhancement as the mechanisms of action for Azone. Alkanols and steroids, both of which are enhanced primarily by lipid fluidization, had different degrees of relative enhancement. This provides evidence that the stratum corneum barrier is heterogeneous, rather than a homogeneous slab barrier. Two effects of Azone on the stratum corneum were detected by DSC. A decrease in the area and a shift to lower temperatures were noted for the lipid endotherms with increasing doses of Azone. A lipid fluidizing effect would qualitatively account for the increases in the permeability coefficients noted for more lipophilic solutes. The stratum corneum keratin endotherm also appears to be altered in the presence of Azone. It is possible that alteration of the keratin structure could lead to the development of polar routes in the stratum corneum.

Treatment of infected knee arthroplasty

Forty-eight patients with 51 infected knee arthroplasties were treated at the authors' institution between 1973 and 1986 and followed for 5.5 (range, 0-14) years. Six methods to treat the infections were employed: antibiotics only, soft-tissue surgery, removal of the prosthesis, revision arthroplasty, arthrodesis, and amputation. Failure of the initial surgical treatment led to second revision surgery in 20 patients. At the follow-up examination, three patients (five knees) had died from septic complications and two patients had had above-knee amputation. Two of 32 patients had been successfully treated with antibiotics with no additional surgery. Four patients had successful soft-tissue surgery. Following removal of the prosthesis, the infection healed in four patients. In 12 of 19 patients (13 knees) with revision arthroplasty the infection healed, but only seven of these had functioning prostheses. The infection healed in all but one of the 21 patients with arthrodeses, and all but two were fused. Infected compartmental prostheses with good bone stock can be treated with an exchange arthroplasty using a two-stage procedure with tricompartmental revision prostheses. Otherwise, an arthrodesis using a two-stage procedure is recommended for the treatment of infected knee arthroplasty.

Treatment of the exposed knee prosthesis

Ten knees with early tissue breakdown after knee arthroplasty resulting in exposed prostheses were treated with different plastic surgical techniques. Six knees were successfully covered: four using a gastrocnemius musculocutaneous flap, one using a fasciocutaneous flap, and one using split-skin grafts. Four knees failed: two using local skin flaps and two using split-skin grafts. A gastrocnemius musculocutaneous flap seems to provide a reliable coverage of the exposed knee joint.

Hematogenous infection after knee arthroplasty

Twenty-five hematogenously infected knee arthroplasties in 20 patients (17 with rheumatoid arthritis and 3 with arthrosis) were followed for 3 years. Staphylococcus aureus was the major infecting organism. Three patients with four arthroplasties died of sepsis. Two patients had removal of the arthroplasty, one of which resulted in an above-the-knee amputation. Four out of five arthrodeses fused. Two knees healed after early debridement and two healed without surgery. Ten knees had successful revision arthroplasty. Rheumatoid arthritis and constrained prostheses increase the risk of hematogenous infection. Any infection and especially cutaneous lesions in a patient with a knee arthroplasty should be treated vigorously.