Preliminary report on a catalyst derived from induced cells of Rhodococcus rhodochrous strain DAP 96253 that delays the ripening of selected climacteric fruit: bananas, avocados, and peaches.

Despite the use of refrigeration, improved packaging, adsorbents, and ethylene receptor blockers, on average, nearly 40% of all fruits and vegetables harvested in the US are not consumed. Many plant products, especially fruit, continue to ripen after harvesting, and as they do so, become increasingly susceptible to mechanical injury, resulting in increased rot. Other plant products during transportation and storage are susceptible to chill injury (CI). There is a real need for products that can delay ripening or mitigate the effects of CI, yet still permit full ripeness and quality to be achieved. Preliminary results are discussed where catalyst derived from cells of Rhodococcus rhodochrous DAP 96253, grown under conditions that induced high levels of nitrile hydratase, were able to extend the ripening and thus the shelf-life of selected climacteric fruits (banana, avocado, and peach). A catalyst, when placed in proximity to, but not touching, the test fruit delayed the ripening but did not alter the final ripeness of the fruit tested. Organoleptic evaluations conducted with control peaches and with peaches exposed to, but not in contact with, the catalyst showed that the catalyst-treated peaches achieved full, natural levels of ripeness with respect to aroma, flavor, sweetness, and juice content. Furthermore, the results of delayed ripening were achieved at ambient temperatures (without the need for refrigeration).

A comparison of two methods of evaluating cornea-to-contact lens base curve fluorescein patterns in keratoconus.

PURPOSE: The purposes of the study were as follows: (1) to compare the apical fitting relationship of habitual contact lens fluorescein patterns in keratoconus as determined by clinician assessment of on-eye patterns to those determined by photograph readers looking at slides of fluorescein patterns and (2) to determine the validity of the techniques used in assessing the apical fitting relationships of rigid corneal contact lenses on keratoconic corneas. METHODS: Central fluorescein patterns of rigid contact lens-wearing keratoconus patients enrolled in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study were graded as "definite touch," "touch," "clearance," or "definite clearance" by certified clinicians. Photographs of these patterns were evaluated independently by certified, masked photograph readers using the same grading scale. RESULTS: Agreement between "re-reads" of the same fluorescein pattern slides by the photograph readers was substantial (weighted kappa = 0.751). Agreement between assessments of habitual fit fluorescein patterns at the baseline vs. the repeat visits was poor for the photograph readers (weighted kappa = 0.254) and moderate for the clinicians (kappa = 0.480). Agreement between clinicians' and photograph readers' assessment of the habitual contact lens fluorescein pattern at the baseline visit was fair (weighted kappa = 0.382). CONCLUSIONS: Repeatability and validity of this technique were fair to excellent. Many factors influence fluorescein pattern interpretation, and improvement of the objective method of fluorescein pattern assessment by photograph readers will require improved methodology that takes these factors into consideration.

Cold ischemia time: an independent predictor of increased HLA class I antibody production after rejection of a primary cadaveric renal allograft.

BACKGROUND: Cadaveric kidneys experiencing longer cold ischemia time (CIT) are associated with higher levels of delayed graft function, acute rejection, and early graft loss. One mechanism to explain these results is that ischemia/reperfusion (I/R) injury makes the allograft more immunogenic by upregulating molecules involved in the immune response (e.g., HLA Class I/II). METHODS: We evaluated the influence of CIT on the production of HLA Class I antibody level, measured by an antihuman globulin panel reactive antibody (AHG PRA) level, in 90 unsensitized recipients of primary cadaveric renal transplants (from a total of 1442 between 1985 and 1997) who rejected their kidneys. RESULTS: By multivariate analysis, a CIT of 15 hr or more (vs. < 15 hr) independently increased the risk of the AHG Class I PRA level being > or = 20% after unsensitized patients rejected their first kidneys (relative risk=3.57; 95% confidence interval=1.26 to 10.14; P=0.01), despite the same degree of Class I/II mismatch between the two CIT groups. The overall mean peak PRA level after primary kidney rejection was significantly lower for the CIT < 15 hr group (25.9%+/-33.9; n=24) compared with the CIT > or = 15 hr group (46.3%+/-36.5; n=66) (P<0.001). CONCLUSION: Longer CIT induces a humorally more immunogenic kidney.

IgM antibodies identified by a DTT-ameliorated positive crossmatch do not influence renal graft outcome but the strength of the IgM lymphocytotoxicity is associated with DR phenotype.

A positive crossmatch that is rendered negative by treating the serum with the IgM-reducing agent dithiothreitol (DTT) is generally reported not to influence short-term renal graft outcome. Its effect on long-term (> or = 3 years) cadaveric and live-donor transplant function, however, is less clear. We evaluated the effect of IgM antibodies in a DTT-ameliorated positive crossmatch (DTT-APXM) on long-term renal graft outcome in 1,290 consecutive cadaveric renal transplants (8-year survival) and 384 live-donor renal transplants (7-year survival) from patients transplanted between 1990 and 1999. The data show that 1- and 8-year graft survival for cadaveric renal transplants in patients with IgM antibodies (n=72) (DWFG censored = 91% and 65%; DWFG not censored = 90% and 60%) was not significantly different from the group without IgM antibodies (n = 1,218) (DWFG censored = 92% and 71%; DWFG not censored = 87% and 55%) (log-rank = 0.25 for DWFG censored, log-rank = 0.92 for DWFG not censored). The one- and seven-year graft survival for live-donor renal transplants in patients with IgM antibodies seen in a DTT-APXM (n = 22) (DWFG censored = 95% and 83%; DWFG not censored = 95% and 66%) was not significantly different from the group without IgM antibodies (n = 362) (DWFG censored = 94% and 81%; DWFG not censored = 92% and 73%) (log-rank = 0.61 for DWFG censored, log-rank = 0.89 for DWFG not censored). DR phenotype was found to be associated with the strong (>40% cell death) IgM reactivity in both black and white patients. In white patients, DR2 was more frequently seen with a strong IgM crossmatch (48.2%) than in molecularly typed controls (28.5%) (P < 0.03) and concomitant with that DR increase, DR4 was decreased in white patients (6.8%) compared with controls (25.5%) (P < 0.02). In black patients with strong IgM reactivity, DR6 was increased in patients (46.1%) compared with controls (20.5%) (P = 0.07) and concomitant with that DR6 increase, DR5 was decreased in frequency in black patients (7.6%) compared with controls (41%) (P < 0.03). These data show that long-term graft survival in renal transplantation is not negatively influenced by the presence of donor-reactive lymphocytotoxic antibodies in the crossmatch ameliorated by serum DTT treatment. They also suggest that the strength of the IgM antibody response is regulated in part by certain gene (s) of the DR region.

HLA-B*4012: a new allele with unique serological features.

We have defined the new allele HLA-B*4012, which had been isolated from a black individual. It was initially recognized as a serologically unique allele when typing her father for renal transplantation. The HLA class I phenotype was A*0201,*6602; B*4001,*4012; Bw6; Cw*0304,*1505. Sequencing from exon 1 through intron 3 of B*4012 was performed. B*4012 is identical to B*4001 and B*4010 in exon 3, and in the 3' part of exon 2, but it is unique in that exon 1 and the 5' part of exon 2 are identical to B*1503, B*1509, B*1510, B*1518, B*1523, and B*1529. The generation of this allele is best explained by a recombination event in exon 2 (break point between nucleotides 205 and 222 from the beginning of the coding region) of B*4001 or B*4010 with one of these B*15 variants as a donor allele. Its unique serological feature (B48, B60, B70, and B72 reactivity) is consistent with the sequence data of its donor alleles.

Successful cadaveric renal transplantation of patients highly sensitized to HLA Class I antigens.

The purpose of our investigation was to evaluate long-term graft survival and the role of histocompatibility in patients who were highly sensitized to human leukocyte antigen (HLA) Class I antigens and received a cadaveric renal transplant. Our multi-institutional study evaluated 7-yr graft outcomes and the histocompatibility requirements of 61 (6.1%) highly sensitized (anti-human globulin panel reactive antibody [AHG PRA], > or = 80%) cadaveric renal transplantation patients, transplanted between 1988 and 1997, among 999 consecutive cadaveric renal transplants. One- and 7-yr graft survival in the high PRA group (n = 61) was 76 and 59%, and was not significantly different from that in the low PRA group (n = 938), 86 and 59% (Wilcoxon = 0.11; log-rank = 0.45) (died with a functioning graft [DWFG] not censored). When those data were divided into primary and regrafts, 1- and 7-yr graft outcomes for high and low PRA groups were not significantly different [(primary, 1- and 7-yr survival: high PRA = 83 and 74%, n = 30, and low PRA = 87 and 61%, n = 825; log-rank = 0.37 for DWFG not censored) (regrafts, 1- and 7-yr survival: high PRA = 70 and 42%, n = 31, and low PRA = 80 and 43%, n = 113; log-rank = 0.36 for DWFG not censored)]. We did observe a subgroup of the high PRA patient group that had inferior graft outcomes. Graft outcome at 1 and 6 yr in the high PRA group for patients who had one to two DR mismatches (65 and 50%, n = 41) was significantly worse than for high PRA patients who had zero DR mismatches with their donors (100 and 78%, n = 20) (log-rank = 0.01 for DWFG not censored). Furthermore, the mean number of HLA-A and -B mismatches was significantly greater in the high PRA/DR-mismatched group (1.7 +/- 1.2, n = 41) compared with the high PRA/zero DR-mismatched group (0.5 +/- 1.1, n = 19) (p < 0.001). Overall, these data suggest that the patient who is highly sensitized to HLA Class I antigens has a long-term graft outcome that is equivalent to less sensitized patients, but that HLA-DR mismatching and a higher degree of Class I mismatching may be poor prognostic indicators in such patients.

Corneal scarring in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study: baseline prevalence and repeatability of detection.

PURPOSE: The multicenter Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study is a prospective, observational study of 1,209 keratoconus patients. We report on the prevalence of corneal scarring in these patients. We also report on the test-retest repeatability of corneal scar documentation at the slit-lamp biomicroscope by trained clinicians and by masked photograph readers and on the scarring-status agreement at baseline between clinicians and photograph readers. METHODS: Clinicians and masked photograph readers graded each cornea as to scarring status. Patients were examined by clinicians, and their corneas were photographed at baseline (2,297 nongrafted eyes of 1,209 patients) and at a repeated visit (258 nongrafted eyes of 138 patients). These photographs were evaluated by the masked readers at the CLEK Photography Reading Center (CPRC). Clinicians reported corneal scars in right eyes at baseline as "definitely not present" in 53.9%, "probably not present" in 8.4%, "probably present" in 8.2%, and "definitely present" in 29.4% of patients. A weighted kappa statistic of 0.83 (95% confidence interval from 0.78 to 0.88) indicates that agreement is excellent between baseline and repeated assessments for the presence of a corneal scar by clinicians. RESULTS: Agreement is very good between baseline and repeated photograph-reader assessments for the presence of a scar, with a weighted kappa of 0.77 (95% confidence interval, 0.72-0.82). The kappa statistic comparing photograph-reader scarring assessments with clinician results was 0.69 (95% confidence interval, 0.66-0.71). CONCLUSION: The data also suggest better agreement between clinicians and readers when Vogt's striae and corneal nerves were observed. The data also suggest better agreement when corneal staining was not observed by the photograph readers. The CLEK Study protocol for determining the presence of scars is highly repeatable.

The clinical course of asymptomatic mesenteric arterial stenosis.

PURPOSE: The incidence of subsequent symptomatic mesenteric vascular disease is unknown for patients who have asymptomatic mesenteric arterial stenosis. The purpose of this study was to determine the risk of developing acute and chronic mesenteric ischemia in patients identified by lateral aortography to have significant mesenteric artery stenosis. METHODS: From 1989 through 1995, 980 consecutive aortograms with anteroposterior and lateral projections were reviewed within 1 week of arteriography to identify patients who had significant mesenteric stenosis but no symptoms of mesenteric ischemia. Eighty-two patients were found to have 50% stenosis of at least one mesenteric artery and were monitored by interview to determine if symptoms of acute or chronic mesenteric ischemia developed. RESULTS: Ten patients were lost to follow-up, and 12 patients were withdrawn from the study because of mild mesenteric arterial disease (1% to 49% stenosis) in combination with more significant disease of other vessels. Follow-up was 1 to 6 years. The overall mortality rate was 40%, and mesenteric ischemia developed in four patients. Each of these four patients had significant (>50%) stenosis or occlusion of the celiac artery, superior mesenteric artery, and inferior mesenteric artery. Eighty-six percent of the 15 patients with significant three-vessel arterial disease had mesenteric ischemia, had other vague abdominal symptoms, or died. CONCLUSIONS: Patients with significant three-vessel mesenteric arterial stenosis should be considered for prophylactic mesenteric arterial reconstruction. Mesenteric arterial reconstruction should be routine when these patients undergo aortic reconstruction for aneurysmal or occlusive disease.

Influence of the Rh (D) blood group system on graft survival in renal transplantation.

BACKGROUND: The Rh (D) blood group system has not traditionally been considered to be a clinically relevant histocompatibility barrier in transplantation since conflicting results of its clinical importance have been reported. METHODS: We analyzed 786 consecutive primary cadaveric renal transplants performed by transplant centers in our Organ Procurement Organization (OPO) between 1990 and 1997. We also analyzed United Network for Organ Sharing (UNOS) data on 26,469 kidney transplants done from April 1994 to June 1996. RESULTS: Multivariate analysis revealed that Rh identity between the recipient and donor was significantly related to better graft outcome (risk ratio, 0.43; 95% confidence interval, 0.30 to 0.61; P=0.0001). Multivariate analysis of the UNOS data revealed that the Rh -/- group may have a positive influence on graft survival with a risk ratio of 0.43 (P=0.14). CONCLUSION: Multivariate analysis of primary cadaveric renal allografts performed within the Midwest Organ Bank OPO indicates that Rh (D) is a clinically relevant histocompatibility barrier that influences 7-year graft survival.

Ten-year experience in transplantation of A2 kidneys into B and O recipients.

BACKGROUND: This article summarizes our 10-year multicenter experience with transplantation of 50 blood group A2 and A2B kidneys into B and O patients. METHODS: Since 1986, we have transplanted kidneys from 46 cadaver donors and 4 living donors who were blood group A2 (47 donors) or A2B (3 donors) into 19 B and 31 O patients. In 1991, we began allocating these kidneys preferentially to B and O recipients who were selected based on a history of low (< or =4) anti-A IgG isoagglutinin titers. Immunosuppression was no different from that used in ABO-compatible grafts. RESULTS: The 1-month function rate before thus selecting the patients was 68% (19/28), but is now 94% (17/18). Two-year cadaver-donor graft survival with this selection method is 94%, compared with 88% for 640 concurrent and consecutive ABO-compatible transplants (log-rank, 0.15). All four living-related transplants are still functioning, with a mean follow-up of 71 months. Since we began allocating A2 kidneys preferentially to B and O recipients, the percentage of the B patients who received A2 or A2B kidneys has increased from 29% (8/28) to 55% (10/18). CONCLUSIONS: Transplantation of A2 or A2B kidneys into B and O patients is clinically equivalent to that of ABO-compatible transplantation when recipients are selected by low pretransplant anti-A titer histories. This approach increases access of blood group B recipients to kidneys.

Transplantation rate of the blood group B waiting list is increased by using A2 and A2B kidneys.

BACKGROUND: We have increased the transplantation rate for blood group B cadaveric waiting list candidates by transplanting them with A2 and A2B kidneys. METHODS: Since 1991, five of the seven renal transplant programs in our organ procurement organization service area have preferentially transplanted blood group A2 and A2B cadaveric kidneys to B blood group waiting list candidates with histories of low anti-A isoagglutinin titers. RESULTS: Between 1991 and 1997, these five centers performed transplantations on 71 patients from the B cadaveric waiting list. Of those 71 patients, 29% (21 of 71) underwent transplantation with either A2 (n=18) or A2B (n=3) cadaveric kidneys. In 1997 alone, 48% (11 of 23) of the B patient transplant recipients received A2 or A2B kidneys. CONCLUSIONS: Transplantation of A2 and A2B kidneys into B waiting list patients has successfully increased access of B patients to kidneys. Such an allocation algorithm implemented nationally may similarly increase the transplantation rate of B waiting list candidates.

Long-term graft survival is improved in cadaveric renal retransplantation by flow cytometric crossmatching.

BACKGROUND: Cadaveric renal retransplantation is associated with a higher risk of early graft failure than primary grafts. A large proportion of those graft losses is likely attributable to donor-directed HLA class I antibodies, detectable by flow cytometry cross-matching but not by conventional crossmatching techniques. METHODS: Long-term graft survival in a group of 106 recipients of consecutive cadaveric renal regrafts between 1990 and 1997, in whom a negative flow T-cell IgG crossmatch was required for transplantation, was compared with two other groups of cadaveric transplant recipients. The first group consisted of 174 cadaveric regrafts transplanted between 1985 and 1995 using only a negative anti-human globulin (AHG) T-cell IgG crossmatch. The second group was primary cadaveric transplants done concurrently with the flow group (1990 to 1997) using only the AHG T-cell IgG crossmatch. RESULTS: The long-term (7 year) graft survival rate of flow crossmatch-selected regraft recipients (68%; n= 106) was significantly improved over that of regraft recipients who were selected for transplantation by only the AHG crossmatch technique (45%; n=174; log-rank=0.001; censored for patients dying with a functioning graft). Graft outcome for the flow cross-matched regraft recipients was not significantly different from that of primary cadaveric patients (72%; n=889; log-rank=0.2; censored for patients dying with a functioning graft). Finally, a positive B-cell IgG flow cytometric crossmatch had no influence on long-term regraft outcome. CONCLUSIONS: The use of the flow T-cell IgG cross-match as the exclusion criterion for cadaveric renal retransplantation yields an improved long-term graft outcome over that obtained when only the AHG cross-match is used and has improved survival of regraft recipients to the level of our primary cadaveric renal transplant population.

Comparison of red-green, blue-yellow and achromatic losses in glaucoma.

Achromatic losses in glaucoma would be expected to be greater than, or equal to, red-green chromatic losses if the following assumptions are made: (1) the function of the remaining axons is either unchanged or non-selectively reduced; (2) red-green chromatic information is signaled by the midget ganglion cell system; and (3) the function of the magnocellular system is reduced at least as much as that of the midget ganglion cells. This prediction was tested by measuring red-green (along with blue-yellow) mixture thresholds for 1 deg, 0.2 sec test spots presented on a color monitor on a white background of 50 cd/m2. Ellipses were fitted to plots of green contrast as a function of red contrast (or yellow as a function of blue), and major and minor axes of these ellipses were taken as measures of chromatic and achromatic thresholds, respectively. The study population consisted of 29 eyes in 29 patients with early glaucoma; control data were derived from a data bank of 83 normal eyes. Red-green losses were significantly (P < 0.05) greater than achromatic losses in 6 out of the 11 eyes which showed significant losses of either chromatic or achromatic sensitivity (or both). It is concluded that, for these eyes, at least one of the above three assumptions is incorrect.

HLA-DR and DQ typing by polymerase chain reaction using sequence-specific primer mixes reduces the incidence of phenotypic homozygosity (blanks) over serology.

Because of the inherent difficulties in allele assignment with HLA-DR serological typing, in 1993 our organ procurement organization-based HLA laboratory replaced serology with the molecular method of polymerase chain reaction using sequence-specific primer mixes (PCR-SSP) to type for DR and DQ at a resolution level equivalent to that of serologically defined antigens. In this study, we compared the incidence of DR blanks, where allocative homozygosity occurred, and graft outcome during our serology epoch (1987-1993) with that of our molecular epoch (1993-1996). The incidence of DR blanks by PCR-SSP (17.0%; 138/1101) was significantly lower (P<0.005) than in the serology epoch (21.5%; 569/2647). Although DQ is not a component of the allocation algorithm, the incidence of blanks in the molecular era (21.9%; 196/895) was 46% lower (P<0.001) than in the serology epoch (40.8%; 931/2277). Graft survival in 163 cadaveric renal transplant recipients for whom molecular DR allocation occurred (patient and donor were molecularly typed) showed that PCR-SSP typing had no significant effect on 2.5-year graft survival for patients mismatched for 0 (97%), 1 (90%), or 2 (94%) HLA-DR antigens (P=0.4; log-rank). In conclusion, molecular typing lowered the rate of DR and DQ blanks, but molecular matching for HLA DR and DQ did not influence graft outcome at 2.5 years.

Transhiatal versus transthoracic esophagectomy for adenocarcinoma of the distal esophagus and cardia.

BACKGROUND: Transhiatal esophagectomy is a popular method of resection because of its reported lower morbidity and mortality and similar survival rates compared to transthoracic esophagectomy. A review of recent experience with these two procedures for resection of distal esophageal and cardia adenocarcinoma is reported. METHODS: From 1988 to 1994, 48 patients with adenocarcinoma of the distal esophagus and gastric cardia were resected with intent to cure, 32 by transhiatal esophagectomy (group 1) and 16 by transthoracic esophagectomy (group II). The two groups were comparable in terms of patient demographics, preoperative risk factors, tumor stage, tumor differentiation, and involvement of resection margins (all not significant [NS]). RESULTS: There was no significant difference in median intensive care unit stay, median hospital stay, incidence of postoperative anastomotic leak, and stricture. Respiratory complications were higher in group I (41% versus 6%, P = 0.01). Hospital mortality was not significantly different for the two groups (group I 3.1% versus group II 0%, NS). Actuarial 5-year survival rates (Kaplan-Meier) were 12% for group I and 39% for group II (NS). CONCLUSIONS: These results suggest that when compared with transhiatal esophagectomy, the transthoracic approach is at least as safe, has comparable complication and survival rates, and remains an acceptable procedure for resection of adenocarcinomas of the distal esophagus and gastric cardia.

Improved graft survival in cadaveric renal retransplantation by flow crossmatching.

OBJECTIVE: To evaluate the role of flow cytometry cross-matching on graft survival in patients undergoing cadaveric renal retransplantation compared with our conventional antihuman globulin cytotoxic crossmatch. DESIGN: In 1990, 6 of 7 transplantation centers in 1 organ procurement organization service area began performing cadaveric renal retransplantation only if the flow T-cell IgG crossmatch was negative. During that period, 1 center continued to use only the antihuman globulin T-cell IgG crossmatch. Prior to 1990, all centers used only the antihuman globulin T-cell IgG crossmatch as their crossmatch selection criterion for retransplantation. Regraft survival was compared between those centers by crossmatch selection criteria. PATIENTS: Patient selection and immunosuppression decisions were made at the transplantation center. SETTING: All flow cytometry crossmatches for all 7 centers participating in the evaluation were performed at the Histocompatibility Laboratory of the Midwest Organ Bank Inc, Westwood, Kan. RESULTS: Graft survival is significantly better (P = .03 [logrank test]) in regrafts when the flow crossmatch is used to select patients for transplantation. CONCLUSION: Flow crossmatching improves graft survival in cadaveric renal retransplantation by identifying a subset of patients with donor-directed HLA class I antibodies that are not detectable by our conventional antihuman globulin crossmatch.