Microbiological effect of the use of an ultrasonic device and iodine irrigation in patients with severe chronic periodontal disease: a randomized controlled clinical study

OBJECTIVE

Instrumentation of the subgingival area is aimed at removing as much as possible of the bacterial biofilm and subgingival calculus. Since mechanical root debridement is a technically demanding procedure, antiseptics and antibiotics delivered either locally or systemically have been used as adjunct to scaling and root-planning procedures in order to control the subgingival biofilm and thereby enhance the treatment outcome. Our aim was to study the microbiological effect of ultrasonic debridement with or without povidone-iodine (PVP-iodine) in the treatment of severe chronic periodontitis.

MATERIAL AND METHODS

Twenty patients were recruited to the study. Each test site and the related quadrant were randomly assigned to one of four different treatment modalities: ultrasonic scaling+subgingival irrigation with 0.5% PVP-iodine for 5 min/tooth, ultrasonic scaling+subgingival irrigation with sterile saline solution for 5 min/tooth, subgingival irrigation with sterile saline solution for 5 min/tooth and subgingival irrigation with 0.5% PVP-iodine for 5 min/tooth. The individuals were followed longitudinally for 6 months.

RESULTS

The present study showed that non-surgical periodontal therapy with the use of an ultrasonic device was effective in reducing the analyzed putative periodontal bacteria. No statistically significant difference between ultrasonic+saline and ultrasonic+PVP-iodine was found.

CONCLUSIONS

Ultrasonic debridement reduced the periodontal markers in patients with severe chronic periodontitis. The reduction was selective. A concentration of 0.5% PVP-iodine did not add any anti-microbiological effect compared to ultrasonic debridement alone.

Quality assurance of the donation process

The quality of the organs harvested from a deceased donor is of critical importance for the outcome of the transplantations. During 2005, a quality assurance project was initiated to evaluate the donor management, harvest operation, and flow of information during the donation process. Three kinds of questionnaires were used in each donation. They were completed by the transplant coordinator, the harvesting surgeon, and the surgeons performing the liver and kidney transplantations. Feedback is given to the harvesting teams within 2 weeks after the procedures. The most important findings related to missed information concerning organ abnormalities or organ damage from the procurement operation. Procurement of organs from a deceased donor involves a complex chain of events. Based on our experiences in this 1-year project, we believe that standardized registration of the various parts of the process and structured feedback to the staff give possibilities to improve performance. After minor modifications, this method for quality assurance has been introduced as a permanent part of our donation procedure. We believe that this strategy can help to detect weaknesses and improve transplant outcomes.

Changing Donation Pattern in Central Sweden

Since 1990, the Organisation for Organ donation in Central Sweden has registered the numbers of donations at the various hospitals in the area. During this period, a significant decrease in donation rate was observed in the large hospitals, while there was an increase in donation rate in the smaller hospitals. Taken together, the small hospitals are now at least as important as the large hospitals. Possible reasons for the observed change in donation pattern are discussed.

Healing following ultrasonic debridement and PVP-iodine in individuals with severe chronic periodontal disease: a randomized, controlled clinical study

OBJECTIVE

Antiseptics and antibiotics delivered either locally or systemically have been used as an adjunct to scaling and root planing procedures in order to control the subgingival biofilm and thereby enhancing the treatment outcome. The results presented in the literature are, however, inconclusive. Povidone-iodine (PVP-iodine) has a bactericidal effect and is effective against most bacteria, including putative periodontal pathogens. The aim of the present study was to evaluate the clinical effect of PVP-iodine as an adjunct to ultrasonic scaling in the treatment of severe chronic periodontitis.

MATERIAL AND METHODS

Twenty patients were recruited to the study. Each test site and the related quadrant were randomly assigned to one of four different treatment modalities: ultrasonic scaling + subgingival irrigation with 0.5% PVP-iodine for 5 min/tooth, ultrasonic scaling + subgingival irrigation with sterile saline solution for 5 min/tooth, subgingival irrigation with sterile saline solution for 5 min/tooth, and subgingival irrigation with 0.5% PVP-iodine for 5 min/tooth. The individuals were followed longitudinally for 6 months.

RESULTS

The present study showed that non-surgical periodontal therapy by means of an ultrasonic device was effective in attaining a healthy periodontal status in patients with severe periodontal lesions. No additive effect was found when PVP-iodine was included.

CONCLUSIONS

Ultrasonic debridement using Odontogain is effective in controlling infection in patients with severe chronic periodontitis. PVP-iodine does not add any clinical benefit to the ultrasonic debridement alone under these circumstances.

Results from a degradable TMC joint Spacer (Artelon) compared with tendon arthroplasty

PURPOSE

A new spacer for the trapeziometacarpal joint (TMC) based on a biological and tissue-preserving concept for the treatment of TMC osteoarthritis (OA) has been evaluated. The purpose was to combine a spacing effect with stabilization of the TMC joint.

METHODS

Artelon (Artimplant AB, Sweden) TMC Spacer is synthesized of a degradable polyurethaneurea (Artelon), which has been shown to be biocompatible over time and currently is used in ligament augmentation procedures. Fibers of the polymer were woven into a T-shaped device in which the vertical portion separates the bone edges of the TMC joint and the horizontal portion stabilizes the joint. Fifteen patients with disabling pain and isolated TMC OA were included in the study. Ten patients received the spacer device and the remaining 5 (control group) were treated with a trapezium resection arthroplasty with abductor pollicis longus (APL) stabilization. The median ages of the 2 groups were 60 and 59 years, respectively. Pain, strength, stability, and range of motion were measured before and after surgery. Radiographic examination was performed in all patients before and after surgery. At follow-up evaluation 3 years after surgery an unbiased observer evaluated all patients. Biopsy specimens were obtained from 1 patient 6 months after surgery.

RESULTS

All patients were stable clinically without signs of synovitis. In both groups all patients were pain free. The median values for both key pinch and tripod pinch increased compared with before surgery in the spacer group but not in the APL group. The biopsy examinations showed incorporation of the device in the surface of the adjacent bone and the surrounding connective tissue. No signs of foreign-body reaction were seen.

CONCLUSIONS

This study showed significantly better pinch strength after Artelon TMC Spacer implantation into the TMC joint compared with APL arthroplasty.

Microbiologic Diagnostics at Titanium Implants

BACKGROUND

The microbiota found at periimplant lesions have been shown to contain putative periodontal pathogens as well as opportunistic species such as Staphylococcus spp, enterics, and Candida spp. Therefore, a microbiologic diagnosis may be of value as guidance before treatment of such lesions.

PURPOSE

The aim of this study was to evaluate the prevalence of some putative pathogens associated with long-term followed-up cases using two different microbiologic procedures.

MATERIALS AND METHODS

Fifteen subjects contributed with plaque samples from teeth and implants; these were analyzed with respect to 18 putative periimplant pathogens using cultural methods and a deoxyribonucleic acid DNA-DNA hybridization technique.

RESULTS

The number of individuals positive for the analyzed pathogens was similar in samples taken from teeth and implants when analyzed with the DNA-DNA hybridization technique. When comparing detection frequency by culture procedure and by "checkerboard" technique at implants, the number of individuals positive for these species was lower with the traditional culture technique than with the checkerboard analyses. Using a higher cutoff point (> or = 4) with the checkerboard technique, the number of positive individuals was generally lower than that found with the culture technique. When comparing the techniques on an implant site level, the prevalence obtained by culture was lower for all analyzed species. If the specific species were present in the samples analyzed by the checkerboard technique, they were present only in every second sample analyzed with the culture technique. The high specificity values showed that if the checkerboard technique did not detect any Porphyromonas gingivalis, Prevotella intermedia, Actinobacillus actinomycetemcomitans, or Fusobacterium nucleatum, the bacteria were also undetectable by the culture technique. The two methods therefore did not overlap but did supplement each other.

CONCLUSIONS

Based on the current results it is recommended that the technique used when analyzing microbiota around titanium implants should be a combination of the two protocols mentioned as they seem to give the most comprehensive outcome when used together.

Long-term follow-up of osseointegrated titanium implants using clinical, radiographic and microbiological parameters

The aim of this study was to longitudinally follow up osseointegrated titanium implants in partially dentate patients by clinical, radiographic and microbiological parameters in order to evaluate possible changes in the peri-implant health over time. Fifteen individuals treated with titanium implants, ad modum Brånemark, and followed for ten years were included in the study. Before implant placement ten years previously, the individuals had been treated for advanced periodontal disease and thereafter been included in a maintenance care program. The survival rate of the implants after ten years was 94.7%. The bone loss was 1.7 mm when using the abutment-fixture junction as a reference point. Of the individuals, 50% were positive for plaque at the implants. Bleeding on sulcus probing was present at 61% of the implant surfaces. Ten years previously, the individuals had been carriers of putative periodontal pathogens, such as Porphyromonas gingivalis, Prevotella intermedia, Actinobacillus actinomycetemcomitans, Capnocytophaga spp. and Campylobacter rectus, and were also carriers of these species at the current examination. The results of the present study suggest that the presence of these putative periodontal pathogens at implants may not be associated with an impaired implant treatment. These species are most likely part of the normal resident microbiota of most individuals and may therefore be found at random at both stable and progressing peri-implant sites.

A comparison of laser-welded titanium and conventional cast frameworks supported by implants in the partially edentulous jaw: a 3-year prospective multicenter study

PURPOSE

The purpose of this prospective multicenter study was to evaluate and compare the clinical performance of laser-welded titanium fixed partial implant-supported prostheses with conventional cast frameworks.

MATERIALS AND METHODS

Forty-two partially edentulous patients were provided with Brånemark system implants and arranged into 2 groups. Group A was provided with a conventional cast framework with porcelain veneers in one side of the jaw and a laser-welded titanium framework with low-fusing porcelain on the other side. The patients in group B had an old implant prosthesis replaced by a titanium framework prosthesis. The patients were followed for 3 years after prosthesis placement. Clinical and radiographic data were collected and analyzed.

RESULTS

Only one implant was lost, and all prostheses were still in function after 3 years. The 2 framework designs showed similar clinical performance with few clinical complications. Only one abutment screw (1%) and 9 porcelain tooth units (5%) fractured. Four prostheses experienced loose gold screws (6%). In group A, marginal bone loss was similar for both designs of prostheses, with a mean of 1.0 mm and 0.3 mm in the maxilla and mandible, respectively. No bone loss was observed on average in group B. No significant relationship (P > 0.05) was observed between marginal bone loss and placement of prosthesis margin or prosthesis design.

CONCLUSION

The use of laser-welded titanium frameworks seems to present similar clinical performance to conventional cast frameworks in partial implant situations after 3 years.

Influence of bicortical or monocortical anchorage on maxillary implant stability: a 15-year retrospective study of Brånemark System implants

The present study evaluated implant survival and marginal bone loss in maxillae over a 15-year follow-up period as a function of either monocortical or bicortical implant anchorage. Of 207 standard Brånemark implants (10 mm in length) followed, 110 implants were judged to be monocortically anchored and 97 as bicortically anchored. The bicortically anchored implants failed nearly 4 times more often than the monocortical ones. Implant fractures accounted for over 80% of the observed failures and were found to affect the bicortical group almost 3 times more often. As tentative explanations, induction of increased stress and bending forces resulting from possible prosthetic misfit, presence of unfavorable arch relationships, or high occlusal tables in combination with bicortically anchored implants have been suggested, all indicating an overambitious fixation of the bicortical anchorage. Total marginal bone loss was low over the 15-year period and close to identical for the 2 groups, suggesting that the mode of cortical anchorage did not have any clinically significant influence on marginal bone remodeling.

On Cutting Torque Measurements during Implant Placement: A 3-Year Clinical Prospective Study

BACKGROUND

Evaluation of jaw bone quality at implant placement is mainly based on preoperative radiographic assessments and subjective hand registrations during implant site preparation. An objective technique with cutting torque measurements has been introduced, presenting an objective bone quality or bone hardness value of individual implant sites.

PURPOSE

The purpose of this study was to evaluate cutting torque measurements during implant placement and to compare these values in different regions in mandibles and maxillae. The objective was to identify implants at risk for failing at implant placement.

MATERIAL AND METHODS

Cutting torque measurements were performed during placement of Mk II self-tapping implants (Brånemark System) in 105 patients, comprising 72 edentulous (40 maxillae) and 34 partially edentulous (22 maxillae) jaws. A total of 523 implants were inserted, of which 420 were of the Mk II design and of which 412 were subjected to cutting torque measurements. Statistical analyses were performed by comparing cutting torque values of maxillae and mandibles and of different jaw regions. Cutting torque values were also correlated with radiographically and clinically assessed bone quality scores. Patients were followed clinically for a minimum of 3 years.

RESULTS

A statistically significant difference in cutting torque values of maxillae and mandibles was seen, although not when comparing anterior and posterior regions within the same jaws or of different jaws. Significant correlations were found between values of cutting torque and bone quality. The majority of failures were seen in bone of medium to high density, whereas implants inserted in bone of poor density presented a better outcome, perhaps due to an adapted surgical protocol and an extended healing period. The overall implant survival rate at 3 years was 95%, and when analyzing different jaw categories, survival rates of 92.0% and 99.4% were seen for edentulous maxillae and mandibles, respectively. The corresponding figures for partially edentulous jaws were 95.4% and 97.6%.

CONCLUSION

It was not possible to identify sites at risk for future implant losses or to determine a lower limit value of cutting torque in order to achieve successful implant integration.

Survival of the Brånemark implant in partially edentulous jaws: a 10-year prospective multicenter study

A total of 127 partially edentulous patients, treated according to the Brånemark protocol, was followed for 10 years after completion of prosthetic treatment. The patients ranged in age from 18 to 70 years, and 57% were female. Four hundred sixty-one implants were placed in 56 maxillae and 71 mandibles. In 125 patients, 163 fixed partial prostheses were attached to the implants; a majority of the prostheses (83%) were located in posterior regions. At the end of the 10-year period, 73% of the implants could be traced either as failed or in function, providing cumulative implant survival rates of 90.2% and 93.7% for the maxilla and mandible, respectively. Of the original fixed prostheses, 63% (cumulatively 86.5%) were still in use, whereas the level of continuous cumulative prosthesis function, including primary and remade restorations, was 94.3% at the end of the evaluation period. Marginal bone resorption at the implants was low (mean = 0.7 mm), and mucosal health was good. No severe complications apart from the above-mentioned implant and prosthetic failures were reported. The Brånemark Implant System is a safe and predictable method for restoring partially edentulous patients, as demonstrated by this 10-year follow-up investigation.

Ceramic implant abutments used for short-span fixed partial dentures: a prospective 2-year multicenter study

PURPOSE

This is a 2-year report from an ongoing prospective 5-year multicenter study. The aim of the study was to evaluate the short- and long-term clinical function of CerAdapt ceramic abutments supporting short-span fixed partial dentures (FPD).

MATERIALS AND METHODS

Initially, 105 Brånemark System implants were placed in a total of 32 patients at 3 different clinics. After initial healing 103 implants remained. For the support of 36 FPDs, 53 ceramic and 50 titanium abutments were connected, 19 on ceramic and 17 on titanium abutments.

RESULTS

All patients remained in the study after 2 years. There was a cumulative survival rate of 97.1% for implants and a cumulative success rate of 97.2% for FPDs (94.7% for ceramic and 100% for titanium abutment-supported FPDs). One of 53 ceramic but none of 50 titanium abutments failed, giving a cumulative success rate of 98.1% and 100%, respectively, for the abutments. Soft tissue around abutments and adjacent teeth appeared healthy. More crown margins were placed submucosally at titanium (31%) than at ceramic (14%) abutments, and the level of the periimplant mucosa was relatively stable in relation to the abutment/crown. No differences were seen between ceramic and titanium abutments regarding bleeding of the periimplant mucosa. There was a minimal marginal bone loss recorded after 1 year, which was slightly more at titanium (0.4 mm) than at ceramic (0.2 mm) abutments. All patients and dentists were satisfied with the achieved esthetic result and no FPD was remade because of compromised esthetics.

CONCLUSION

So far the ceramic abutments have worked very well and the 2-year results have been very encouraging for CerAdapt abutments supporting short-span FPDs. However, ceramic materials tend to undergo static fatigue, and it is therefore important to wait for the 5-year results before making any more definite statement about the long-term prognosis for CerAdapt abutments.

Labelling indices in human tumours: to apply corrections or not--that is the question

The advent of halogenated pyrimidines (bromodeoxyuridine, BrdU; idoxuridine, IdU) and antibodies to recognize them has opened new horizons for the measurement of proliferation in human tumours. These precursors of DNA can be given to patients and a single biopsy can be taken to measure in a flow cytometer both the fraction of labelled cells and their rate of movement through the S phase. From these two parameters the potential doubling time, T(POT), can be calculated. To measure both parameters simultaneously a compromise is made in the time of assessing the labelling index (LI). LI should ideally be assessed after a very short interval, e.g. 0.5-1 h, to avoid the contaminating influence of any cells dividing between injection and biopsy. However, an interval of 4-8 h is considered necessary to assess T(S) from the relative movement of cells through the S phase. Several techniques exist to correct for cell division if the interval is long. The simplest correction, which only corrects for the division of labelled cells, is most widely used. Downward correction factors of at least 10% are commonly applied, reducing the observed LI values. In this paper we illustrate graphically the dependence of the appropriate correction factor on various cell kinetic parameters. The duration of G2 is the most critical parameter for both the size and direction of any correction factor. The G2 phase has previously been shown to be about three times longer in human tumours than in rodents. If G2+M is as long as 6 h, the main artefact of the intervals between injection and biopsy up to 7 h is that the observed LI is too low because of division of unlabelled G2 cells. A correction of up to 10% is needed but in an upward direction. A nomogram of probable correction factors as a function of sampling interval is provided. We show from flow cytometric data that G2+M may be shorter than 4 h for head and neck tumours. It is recommended that the correction factor established by gating the flow histogram should always be checked against this nomogram, or that no correction factor should be applied. We have used this mathematical approach to re-evaluate two sets of published LI data for rectal and colorectal tumours. We show that the mathematical correction of each data point leads to a 30% increase in the median value, compared to the simple gating procedure. We question whether other of the published series of LI values gained with BrdU or IdU may also substantially underestimate the true LI values, if a simple gating procedure has been used in an attempt to reduce the impact of divided S phase cells.

Influence of variations in implant diameters: a 3- to 5-year retrospective clinical report

Sixty-seven patients ranging in age from 16 to 86 years were included in this 3- to 5-year retrospective report focusing on implant survival and marginal bone remodeling in relation to implant diameter. A total of 299 Brånemark implants (3.75-mm diameter: 141; 4.0-mm diameter: 61; 5.0-mm diameter: 97) were placed in 16 completely and 51 partially edentulous arches. Seven of the 141 implants in the 3.75-mm-diameter group failed (5%). The corresponding value for the 4.0-mm-wide implants was 2 of 61 (3%). The highest failure rate, 18% (17/97), was seen for the 5.0-mm-diameter implants. The least favorable cumulative survival rates were seen in mandibles after 5 years and involving 4.0-mm- and 5.0-mm-diameter implants (84.8% and 73.0%, respectively). The marginal bone loss was generally low over the 5-year period. When the data were evaluated by the Cox regression analysis, a relationship was found between implant failure and implant diameter (P < .05), with a higher failure rate for the 5.0-mm-diameter implant. However, no relationship could be seen between implant failure and jaw type, or bone quality and quantity (P > .05). Neither was any relationship seen between marginal bone loss and bone quality and quantity, implant diameter, or jaw type when tested by multiple linear regression analysis (P > .05). A learning curve, poor bone quality, and changed implant design were suggested as possible reasons for the less positive outcome seen for the 5.0-mm-diameter implant. The fact that this implant was often used as a rescue implant when the standard ones were not considered suitable or did not reach initial stability was another plausible explanation.

Laser-welded titanium frameworks supported by implants in the edentulous maxilla: a 2-year prospective multicenter study

PURPOSE

The aim of this study was to evaluate the clinical and radiographic performance of patients who received implants and fixed prostheses with laser-welded titanium frameworks.

MATERIALS AND METHODS

Fifty-eight consecutive patients were treated with 349 osseointegrated implants ad modum Brånemark in the edentulous maxilla at 6 implant centers. The patients were randomly arranged into 2 groups at the time of final impression. Twenty-eight patients received laser-welded titanium frameworks and 30 patients received conventional cast frameworks. Clinical and radiographic data were collected for 2 years in function.

RESULTS

The 2 groups of patients showed similar results. The 2-year overall cumulative implant survival rate from the time of implant placement and prosthesis insertion was 93.7% and 96.2%, respectively. The corresponding cumulative survival rate for prostheses was 96.6%. Two patients, 1 from each group, failed completely and resumed using conventional complete dentures. The only obvious factor that could possibly be related to the 2 complete failures was a smoking habit. However, it was not possible to significantly correlate implant failures to smoking habits in this study. No fractures were observed in the frameworks or implant components, and both groups experienced the same frequency of resin veneering material fractures. The overall average marginal bone loss was 0.4 mm (SD 0.8 mm).

CONCLUSION

Patients treated with implant-supported prostheses fabricated with laser-welded titanium frameworks in the edentulous maxilla presented comparable results to patients with conventional cast frameworks after 2 years in function.

Systematic heterogeneity and prognostic significance of cell proliferation in colorectal cancer

The prognosis of colorectal cancer has not significantly changed during the last 30 years. While evaluation of tumour cell proliferation may provide prognostic information, results obtained so far have been contradictory Heterogeneity in tumour cell proliferation may explain these contradictions. With in vivo injection of iododeoxyuridine (IdUrd), estimation of labelling index (LI), S-phase transit time (Ts) and potential doubling time (Tpot) may be performed from a single sample. A total of 109 colorectal cancers were studied after in vivo injection of IdUrd before surgical removal. From each cancer, four to eight samples were processed for both flow cytometrical (FCM) and immunohistochemical (IHC) visualization of IdUrd incorporation. LI/IHC was morphometrically quantified at both the luminal border and the invasive margin of these tumours. LI was significantly higher at the luminal border compared with the invasive margin, although they were correlated with each other. Using combined IHC and FCM methods, rapidly growing colorectal cancers (high LI and/or low Tpot) showed an increased survival (significant for LI at the invasive margin and for Tpot at both the invasive margin and the luminal border) in the entire unselected material and for radically removed Dukes' B tumours. FCM data alone did not discriminate for survival, with the exception of Ts in diploid and radically removed Dukes' B tumours.

Factors influencing the estimates of proliferative labelling indices in rectal cancer

PURPOSE

A detailed analysis was undertaken of some of the factors influencing the estimate of the labelling index (LI).

MATERIALS AND METHODS

Thirty-three human rectal carcinomas were studied for their proliferative activity as measured by the fraction of cells labelled with a single injection of IdUrd 1-8 h before surgical resection. Adjacent specimens were stained both for histological examination and for flow cytometry (FCM) assessment of labelled nuclei.

RESULTS

Two major differences were found. The superficial parts of each tumour almost always had significantly higher LI values than the deep part (34 versus 21%), yielding an average LI of 27%. The flow cytometry average value was much lower (17%). This was partly due to the influence of diploid tumours. There was a marked heterogeneity in the values, both within tumours, between tumours and between techniques. The average LI for the whole group differs by a factor of three, depending on the method of assessment.

CONCLUSIONS

All these values indicate a varying but rapid proliferative turnover of cells, surprisingly being more marked in the superficial region, i.e. the opposite from the proliferation pattern of the normal rectal mucosa. A biopsy, if taken from the superficial part of the tumour, would therefore be biased toward higher values. This has implications for biopsy sampling for cell kinetic analysis. Histological assessment avoids the contaminating effect of stromal cells, allows architectural arrangements to be detected and is presumably a more realistic representation of proliferative activity.

The Swedish Transplant Coordinators' experience of the new Transplantation Act and the donor register 1 year after implementation

The register has been a support for the coordinators in Sweden when the relatives have said one thing and the deceased person another in regards to donation. Most of the staff are positive to the register and the safety regulations around it. Most often it has been a relief for the relatives that the deceased person's wishes also have been documented in the register or in the donor card. Most decisions are still, however, made by relatives. There is still a need for more positive information about transplantation and its value.

Is kidney transplantation in sensitized recipients justified?

The objective of the study was to determine if it is justified to use the scarce resources of cadaveric kidneys on HLA-sensitized patients, by reviewing the initial and long-term outcome of cadaveric renal transplantation at Uppsala University Hospital, Sweden. Between January 1988 and December 1994, 402 renal transplantations were performed. The patients were divided into one group of sensitized recipients (peak panel antibody reactivity > or = 25%; n = 84) and a second of non-sensitized recipients (panel reactive antibodies < 25%; n = 318). The groups were comparable in terms of recipient and donor age, gender, HLA-A, -B and -DR mismatches and numbers of diabetics. None of the sensitized patients received a six-antigen-matched kidney. For the non-sensitized group, life table analysis showed a 1-year actuarial graft survival (GS) of 91.8% and a 4-year GS of 84.4%. The corresponding GSs for the sensitized group were 79.9% and 68.7%, respectively (P < 0.01). The statistical significance vanished if patients with primary non-function were excluded. When excluding donors above 55 years of age, kidneys with cold ischemia time above 20 h, and two-antigen (HLA-DR) mismatches, there was no detectable difference between the non-sensitized and sensitized groups at 1-year or 4-year GS. Although there is a statistical significance in GS between non-sensitized and sensitized recipients of a kidney transplant, this does not differ from other risk groups such as diabetics, rheumatoid disease sufferers or elderly recipients. We therefore conclude that the sensitized patient should be accepted on the waiting list for a kidney transplant and that it is worthwhile to do the utmost to transplant this category of patients. Our data indicate that kidney GS in sensitized recipients is more affected by negative risk factors such as older donors, long cold ischemia time and two-antigen HLA-DR mismatch, than the non-sensitized recipient. To improve the outcome, those negative factors should be avoided or reduced.

DNA content in colorectal carcinoma: a flow cytometric study of the epithelial fraction

The aim of this study was to estimate the proliferative activity of the epithelial fraction in human colorectal carcinomas. Cell suspensions from 27 human colorectal carcinomas were simultaneously selected for epithelial cells and analyzed for DNA content. The staining procedure we employed, after dispersing the tumour sample into a single-cell suspension, included propidium iodide and a monoclonal antibody to the intermediate filament cytokeratin specific for secretory epithelia of normal human tissue and cells of epithelial origin in adenocarcinomas. This technique made it possible to distinguish the epithelial cell population from non-epithelial cells in the tumour. Flow cytometry was used for DNA analysis and the results obtained after epithelial selection were compared with conventional DNA analysis of crude tumour tissue. No difference in S-phase values of diploid and aneuploid cytokeratin positive cells were seen, whereas analysis of crude tumour cell suspensions showed lower S-phase values in diploid tumours compared to aneuploid ones. When cytokeratin-positive cells in the tumour were selected, we found presence of diploid tumour cells in almost all aneuploid tumours.

Is repeated mismatching at regrafting deleterious?

We reviewed our clinical experience of allowing kidney regrafting with a repeated HLA mismatch. We also permitted a weakly positive B-cell cross-match. All patients who received a second or subsequent renal graft (n = 92) between January 1985 and June 1990 were analysed for graft survival. The overall 1-year graft survival was 70%. A repeated mismatch occurred in 29 of the patients at at least one HLA locus and their 1-year graft survival was 66%. The balance of the regrafts (63) were performed without a repeated mismatch, and their 1-year graft survival was 70%. Even a weakly positive B-cell cross-match was deleterious; when a grafting with a repeated mismatch was performed only one out of five grafts survived. Our results indicate that retransplantation of renal grafts with a repeated mismatch in the HLA A or B locus can be performed without a negative influence on transplant outcome provided that both the T- and B-cell cross-matches are negative.