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Biomedical subjects

L B Johnson

Publications and source records attributed to L B Johnson.

At least 91 records · Page 5Linked to original sources
PubMed1996

Liver transplantation for adult polycystic liver disease.

Patients with adult polycystic liver disease and massive cystic replacement of the liver may present with severe debilitation and impairment of functional performance or, rarely, with signs of portal hypertension or hepatic dysfunction. In those patients incapacitated by severe hepatomegaly secondary to massive cystic replacement with predominantly small cysts (2 cm) without areas of parenchymal sparing, liver transplantation is a therapeutic option. Five patients with incapacitating symptoms from polycystic liver disease underwent liver transplantation as a final therapeutic procedure. Two patients had previous fenestration procedures without significant relief. All patients had radiographic evidence of concomitant polycystic kidney disease; two of these patients were dialysis-dependent at the time of liver transplantation. One patient underwent combined liver-kidney transplantation, whereas another received a six-antigen matched kidney transplant 64 months after liver transplantation. Four of five patients are alive 84, 39, 20, and 8 months after successful liver transplantation. All four have returned to normal functional status with complete resolution of symptoms. Liver transplantation is a suitable option for the patient with bilobar small cystic liver disease without areas of parenchymal sparing. However, only patients with severely compromised functional status should be offered this therapy. Concomitant renal evaluation is mandatory, and a knowledge of the natural history of this disease will aid in the decision of whether a combined liver-kidney transplantation is indicated.

Adult↗
PubMed1996

Utilization of the older donor for renal transplantation.

BACKGROUND: The persistent shortage of ideal donor organs has resulted in increased transplantation of kidneys from older donors (age > 60 years). The overall experience with this donor subgroup indicates decreased graft survival. METHODS: The records of 413 renal transplants performed between July 1991 and July 1995 were reviewed in a retrospective fashion to determine those patients who had received a cadaveric (CT > 60; n = 17) or living donor (LT > 60; n = 7) renal transplant from an older donor. Control groups consisted of randomly selected patients who received cadaveric (CT < 50; n = 20) or living related (LT < 50; n = 20) renal transplants from donors less than 50 years of age. RESULTS: In the CT > 60 group, 1-year graft survival was 57.4%, significantly less than in those of the LT < 50 (100%), LT > 60 (100%), and CT < 50 (89%) groups. Mean recipient serum creatinine in the CT > 60 group was twofold greater than that of other groups at 1, 6, and 12 months following transplantation. Cold ischemia time and creatinine clearance correlated highly with graft survival. Stepwise regression analysis showed creatinine clearance to be the sole independent predictor of graft survival. A calculated donor creatinine clearance < 50 mL/minute was associated with ultimate graft loss. CONCLUSION: Age alone should not be an exclusion criterion to renal organ donation. When considering the older renal donor, creatinine clearance should be included within the decision algorithm.

Actuarial Analysis↗
PubMed1996

Double adult renal allografts: a technique for expansion of the cadaveric kidney donor pool.

BACKGROUND: A major impediment to kidney transplantation is the current shortage of donor organs. Currently approximately 22,500 candidates are awaiting kidney transplantation, while the number of donors remains stable at approximately 3500 each year in the United States. Alternative approaches to traditional organ donor selection are necessary. In this setting we hypothesized that kidneys with reduced nephron mass from adult donors may provide satisfactory renal function if both donor kidneys are placed into a single recipient. METHODS: Eighteen paired adult renal allografts were transplanted into nine adult recipients (DUAL). Recipient graft outcome variables were examined and compared with outcomes from single kidneys transplanted from randomly selected "ideal" donors younger than 50 years of age (CONT < 50) and "expanded" donors older than 60 years of age (CONT > 60) who underwent transplantation at our center. RESULTS: Six-month serum creatinine levels in the three groups, DUAL (n = 9), CONT < 50 (n = 20), and CONT > 60 (n = 12), were 1.6 +/- 0.3, 2.3 +/- 0.3, and 4.1 +/- 0.9 mg/dl, respectively, (p < 0.0001) between CONT > 60 and the other two groups. Mean estimated creatinine clearance (ml/min/1.73 m2) was 43.2 +/- 3.4, 62.5 +/- 5.4, and 24.5 +/- 5.3 (p < 0.02). Graft and patient survival at last follow-up in DUAL was 100% compared with 95% in CONT < 50 and 75% graft and 83% patient survival in CONT > 60. Delayed graft function occurred in one of nine patients (11%) in DUAL group compared with 4 of 20 (20%) in CONT < 50 group and 6 of 12 (50%) in CONT > 60 group. Mean follow-up of patients in DUAL group was 6.6 months (range, 2 to 14 months). CONCLUSIONS: Double adult kidney transplants (DUAL) are associated with acceptable short-term graft function, graft survival, and patient survival when compared with transplanted kidneys from an ideal donor group (CONT < 50). Double renal allografts are a preferred use for donor kidneys with suboptimal nephron mass. Long-term follow-up is required to validate further the proposed approach.

Adult↗
PubMed1996

Significance of the Banff borderline biopsy.

In the Banff classification of kidney transplant pathology the "borderline changes" category falls short of a diagnosis of mild acute rejection, with the recommendation that no treatment is a possible clinical approach. We reviewed the clinical course of patients whose renal allograft biopsies showed "borderline changes" to determine how often these histologic findings actually represented acute rejection. Between January 1992 and June 1994, 351 biopsy specimens were obtained from 170 renal allografts and graded according to the Banff criteria. Eighty-one biopsy specimens were classified as "borderline changes" (23%). Of these, 59 had Banff scores of i1, t1, and vO; the remaining 22 had scores of i2, t1, and vO (i = interstitial infiltrate, t = tubulitis, and v = vasculitis). Medical record review showed that nearly all the "borderline" biopsies had been performed because of an elevated creatinine (Cr; 78 of 81 [96%]), with a mean increase of 1.1 +/- 0.1 mg/dL (+/- SE) over baseline. Most of the patients with "borderline changes" and elevated Cr were treated for acute rejection (61 of 78 [78%]); some with pulse steroids alone (29 of 61 [48%]), the rest with antilymphocyte antibody (32 of 61 [52%]). Among all 61 patients with "borderline" biopsies treated for rejection, 26 had a complete response (43%), 17 had a partial response (28%), and 18 had no response (30%). Interpretation of these changes in Cr, however, was confounded by intercurrent conditions in 28 of the patients. A group of 33 patients was therefore identified in whom a "borderline changes" biopsy was obtained, who were treated for rejection, and in whom all other identifiable causes of elevated Cr other than possible acute rejection had been systematically eliminated from consideration. In this group the mean Cr was 2.0 +/- 0.1 mg/dL at baseline, 3.3 +/- 0.2 mg/dL at the time of biopsy, and 2.2 +/- 0.1 mg/dL 1 month after treatment (P < 0.001 Cr at biopsy v Cr 1 month later). Among these 33 patients, 19 had a complete response (58%), 10 had a partial response (30%), and four had no response (12%). Therefore, the Cr in 88% of the patients in this group was lower 1 month after treatment for rejection than it was at the time of the biopsy. Follow-up biopsies were performed within 1 month of the "borderline" biopsy in 24 cases; these showed "borderline changes" (five of 24 [21%]), mild acute rejection (eight of 24 [33%]), or moderate to severe acute rejection (11 of 24 [46%]). We conclude that in the clinical setting of deteriorating renal graft function with mild elevation of serum Cr, the "borderline changes" biopsy frequently represents acute rejection. Antirejection treatment is therefore appropriate in the majority of cases. The reader should bear in mind that the current study is retrospective, with no control group. The risk of loosely interpreting these data is that some patients will be treated without due cause. Banff "borderline changes" should be used as part of an algorithm, but not the sole criterion, for therapeutic decision making.

Biopsy↗
PubMed1996

Equivalent success of simultaneous pancreas kidney and solitary pancreas transplantation. A prospective trial of tacrolimus immunosuppression with percutaneous biopsy.

OBJECTIVE: This study was designed to evaluate the results of solitary pancreas transplantation in a protocol that uses the new immunosuppressant tacrolimus (FK) and liberally applies ultrasound-guided percutaneous pancreas biopsy to diagnose rejection. SUMMARY BACKGROUND DATA: Pancreas graft survival in patients who simultaneously receive a kidney transplant (SPK) historically has been 75% to 90% at 1 year, approaching that of cadaveric kidney transplantations. In sharp contrast, graft survival rates in patients who receive a pancreas atone (PA) have remained static over the past decade, with approximately 50% functional at 1 year. It was hypothesized that the results of PA transplantations would improve with newer maintenance immunosuppressants and biopsy techniques. METHODS: Twenty-seven PA recipients prospectively were treated with FK-based immunosuppression (PA-FK). Percutaneous biopsy was performed for hyperamylasemia, hyperlipasemia, hypoamylasuria, or unexplained fever. One year pancreas graft survival in these patients was compared to 15 cyclosporine treated PA cases (PA-CsA) and 113 SPK recipients. RESULTS: The 1-year pancreas graft survival rate of 90.1% in technically successful PA-FK patients was significantly better than the 53.4% rate in PA-CsA recipients (p = 0.002) and no different than the 87.4% rate in SPK recipients. The only graft lost to acute rejection in the PA-FK group was because of acknowledged patient noncompliance. Percutaneous biopsy substantially improved the diagnostic certainty in cases of suspected rejection and was associated with a low complication rate (3/178 = 1.5%). CONCLUSIONS: Modern immunosuppression and biopsy techniques have improved the success of solitary pancreas transplantations to the point where outcome is now equivalent to that of SPKs.

Adult↗
PubMed1996

Pancreas transplantation at the University of Maryland.

1. The University of Maryland pancreas transplant program was initiated in July 1991. Through December 1996, 230 pancreas transplants were performed (145 SPK, 64 PAK, 21 PTA). Overall one-year patient and graft survival rates were 95.5% and 78.9%, respectively. 2. The majority of pancreases have been transplanted simultaneously with a kidney. The one-year patient, pancreas and kidney survival rates for SPK transplants were 95.5%, 91.9%, and 82.5%, respectively. 3. Pancreas alone (PA = PAK or PTA) transplants have represented an increasing proportion of the total in recent years. Although the results of PA were previously inferior to SPK transplants, recent developments have made the outcomes equivalent. The advent of FK and MMF have sharply reduced graft losses due to irreversible rejection. Percutaneous pancreas biopsy now provides a safe and effective means to diagnose acute rejection in a timely manner. Anticoagulation protocols have markedly reduced the risk of idiopathic postoperative graft thrombosis. The most recent series of 71 PA cases at our center had a one-year graft survival rate of 75.8% overall, and 88.2% for the 61 technically successful ones. 4. The most widely practiced pancreas transplant technique in the US today includes bladder drainage of exocrine secretions. This results in a high incidence of bladder complications, which can be avoided by enteric exocrine drainage. The most recent series of pancreas transplants at the University of Maryland have been enteric drained, encompassing about half of all cases. Adoption of this technique has eliminated bladder complications, and has not been associated with an increase in anastomotic leaks, infectious complications or graft loss. 5. Most pancreas transplants have had systemic venous drainage via the iliac vein. We recently adopted the portal venous drainage technique, since it eliminates the peripheral hyperinsulinemia associated with systemic drainage, and may therefore improve lipid metabolism and possibly reduce the risk of progression of atherosclerosis. Early results have been favorable. 6. At present the major determinant of pancreas transplant outcome is donor quality. We have emphasized the importance of using pancreases free of fatty or fibrotic transformation, which have been skillfully procured from young, stable, non-obese donors.

Diabetes Mellitus, Type 1↗
PubMed1995

Early experience with a new ePTFE vascular prosthesis for hemodialysis.

BACKGROUND: An expanded polytetrafluoroethylene (ePTFE) graft for hemodialysis designed for immediate cannulation was tested. The graft contains a cannulation segment consisting of a stretch ePTFE base tube surrounded by flat and round ePTFE fibers that are secured by a thin, perforated ePTFE cover. This study reports our early experience with this new vascular prosthesis. PATIENTS AND METHODS: Between June 1994 and March 1995, 48 arteriovenous grafts were implanted in 47 patients for whom autogenous fistula construction was impossible. Mean patient age was 57 years (range 37 to 85), 86% of the patients were black, and 60% were men. Twenty-two (46%) grafts were in the forearm, 19 (39%) in the upper arm, and 7 (15%) in the groin. Unassisted and assisted patency rates were calculated by the Kaplan-Meier method. The times of first hemodialysis relative to implantation and the times to hemostasis after first decannulation were recorded. Explanted grafts were histologically evaluated with hematoxylin and eosin and Gram's stains. RESULTS: The unassisted and assisted 6-month patency rate were 42% and 73%, respectively. Five of the first 10 graft were lost to management and technical errors, after which the respective patency rates were 56% and 82%. Eleven of 22 thrombosed grafts were salvaged, 9 with urokinase thrombolysis and 2 with surgical thrombectomy. Twenty-eight grafts were cannulated within 7 days. The time to hemostasis was usually 2 to 4 minutes and always less than 15 minutes. Histologic analysis of a graft explanted at 40 days showed good fibrous incorporation and capillary ingrowth between the cover and round fibers. CONCLUSIONS: This new ePTFE vascular prosthesis can be safely cannulated immediately after implantation, avoiding the morbidity of temporary central venous catheter hemodialysis. After an initial period of familiarization, patency similar to that of other ePTFE arteriovenous grafts was achieved. For patients requiring urgent hemodialysis, this graft is an ideal alternative that allows immediate, safe cannulation.

Adult↗
PubMed1994

The National Epidermolysis Bullosa Registry.

Since its inception in 1986, the NEBR has proved to be an excellent example of how a relatively small allocation of federal research funds for the development of a registry of cases of a single rare disease can have a major impact on the rapid expansion in the depth of knowledge of not only the disease itself but of a number of associated biologic principles, including keratinization and epithelial cell-extracellular matrix interactions. At present, the NEBR is generating extensive clinical, laboratory, and demographic data, both from cross-sectional and longitudinal perspectives, as well as establishing a centralized cell and tissue bank that will serve the scientific community at large as a valuable resource for future basic research on this oftentimes devastating genetic disease.

Data Collection↗
PubMed1993

Oral involvement of recessive dystrophic epidermolysis bullosa inversa.

The inversa subtype of autosomal recessive dystrophic epidermolysis bullosa (EBDR-I) is a rare variant characterized by lesions involving primarily the flexural areas of the body. The purpose of this investigation was to characterize the oral manifestations of this unusual dermatologic condition. Ten individuals having EBDR-I were evaluated and compared with an age and sex-matched population of unaffected individuals that served as controls. The diagnosis of EBDR-I was confirmed by skin biopsy that demonstrated tissue separation below the lamina densa and the clinical presentation of blister formation that typically localized to flexural areas. There was clinical variability in the severity and distribution of skin involvement; however, none of the affected individuals demonstrated pronounced digital webbing, severe generalized blistering or growth retardation characteristic of the Hallopeau-Siemens form of EBDR. Oral involvement was seen in all cases with ankyloglossia, loss of tongue papillae and obliteration of the oral vestibule between the lips and gingiva being typical. The oral opening was significantly reduced in older EBDR-I individuals compared with matched controls, confirming that acquired microstomia is a characteristic of EBDR-I. The teeth were not clinically abnormal or malformed and showed no evidence of generalized enamel hypoplasia. Despite this, the prevalence of dental caries in EBDR-I individuals was significantly higher than the control group. The inversa form of EBDR presents with oral findings that are similar but generally milder than those seen in the Hallopeau-Siemens variant of EBDR.

Epidermolysis Bullosa Dystrophica↗
PubMed1993

Expression of a cysteine proteinase inhibitor (oryzacystatin-I) in transgenic tobacco plants.

Expression of cysteine proteinase inhibitors (cystatins) in tobacco or other plants has the potential for improving resistance against pathogens and insects that possess cysteine proteinases. A chimeric gene containing a cDNA clone of rice cystatin (oryzacystatin-I; OC-I), the cauliflower mosaic virus 35S promoter, and the nopaline synthase 3' region was introduced into tobacco plants by Agrobacterium tumefaciens. The presence of the chimeric gene in transgenic plants was detected by a polymerase chain reaction-amplified assay, and transcriptional activity was shown by RNA blot analysis. Heated extracts from transgenic tobacco plants, as well as from progeny which were obtained by selfing a primary transformant, contained protein bands that corresponded in molecular mass to OC-I and reacted with antibodies raised against rOC, a recombinant OC-I protein produced by Escherichia coli. Similar bands were absent in extracts from untransformed control plants. OC-I levels reached 0.5% and 0.6% of the total soluble proteins in leaves and roots, respectively, of some progeny. On a fresh weight basis, the OC-I content was higher in leaves (50 micrograms/g) than in roots (30 micrograms/g). OC-I was partially purified from protein extracts of rice seeds and from transgenic tobacco leaves by affinity to anti-rOC antibodies. OC-I from both sources was active against papain.

Cystatins↗
PubMed1993

Development defects of enamel in humans with hereditary epidermolysis bullosa.

Developmental defects of enamel are often reported as a feature of the more severe forms of epidermolysis bullosa (EB). The purpose of this investigation was to determine the prevalence and character of enamel defects in each of the major hereditary EB types. Clinical evaluations were made on 237 individuals representing all of the major EB types and 58 unaffected individuals. All EB cases were categorized by phenotype, mode of inheritance and skin biopsy. The frequency of individuals having developmental enamel defects ranged from 8.6% in recessive dystrophic EB to 100% in junctional EB; 27.5% of the control population had these defects. Generalized hypoplasia characterized by either severe pitting and/or thin enamel was seen in all junctional EB cases but not in any other EB type. There was a tendency for the severe Herlitz form of junctional EB to have thin enamel while non-Herlitz junctional EB cases had less severe pitting and generally no reduction in enamel thickness. The prevalence of individuals with hypoplastic enamel bands was greater in the EB population (9.7%) than controls (1.9%). Thus individuals with simplex and dominant dystrophic EB typically have enamel defects that are similar in frequency and distribution to those of unaffected individuals. Developmental defects of enamel are a consistent feature of junctional EB, although the clinical expression is highly variable.

Adolescent↗
PubMed1993

Intracytoplasmic retention of type VII collagen and dominant dystrophic epidermolysis bullosa: reversal of defect following cessation of or marked improvement in disease activity.

It has been recently shown that the presence of perinuclear "stellate bodies" within the epidermis in patients with a form of dominant dystrophic epidermolysis bullosa named "transient bullous dermolysis of the newborn" corresponds to collections of type VII collagen. To determine the temporal relationship of this unique immunohistochemical defect with course of clinical disease activity, we have longitudinally studied the expression of two epitopes of type VII collagen (LH 7:2; L3d) in nine patients in four such kindreds by immunofluorescence and immunoelectron microscopic technique. In every infant so studied at the time of active blistering, type VII collagen was detectable primarily within basilar and, to a lesser extent, suprabasilar keratinocytes. In contrast, type VII collagen was detectable solely in linear array along the dermoepidermal junction in skin from each patient following complete cessation or at least marked diminution of visible clinical disease activity. These findings support the hypothesis that the temporary mechanical fragility and blistering of the skin in infants with this rare subset of dominant dystrophic epidermolysis bullosa reflect the presence of reduced amounts of type VII collagen along the dermoepidermal junction, and that this diminution may be the result of either a delay in transport and integration of type VII collagen from basilar keratinocytes into the skin basement membrane or excessive phagocytosis of type VII collagen.

Adult↗