PubMed Health⌕ Search

Biomedical subjects

P C Guzzetta

Publications and source records attributed to P C Guzzetta.

At least 37 records · Page 2Linked to original sources
PubMed1992

Successful induction of long-term specific tolerance to fully allogeneic renal allografts in miniature swine.

Major histocompatibility complex class II matching is of overwhelming importance for achieving tolerance to kidney transplants (KTX) in miniature swine. When class II antigens are matched, long-term specific tolerance across complete MHC class I antigen barriers can uniformly be induced by a 12-day perioperative course of cyclosporine. This same regimen is ineffective in fully MHC-mismatched combinations. We hypothesized that initial induction of tolerance to kidney donor class II antigens by bone marrow transplantation might allow tolerance to be induced to a subsequent fully allogeneic KTX in combination with CsA therapy. We report here the results of such fully allogeneic KTX performed in 4 recipients of prior single-haplotype class II-mismatched BMT. All animals received KTX from donors class II matched to the BMT donor and received a 12-day course of intravenous CsA (10 mg/kg/day). All four animals have maintained normal serum creatinine values (less than 2.0 mg/dl) for greater than 200 days posttransplant. Specific hyporesponsiveness to both BMT and KTX donor-type MHC antigens was found in mixed lymphocyte culture and cell-mediated lympholysis assays. Compared with third-party grafts, significantly prolonged survival of BMT donor-specific (P = 0.031) and KTX donor-specific (P = 0.031) skin grafts was observed. These results demonstrate that induction of tolerance to class II antigens by BMT allows a short course of CsA to induce specific tolerance to fully allogeneic renal allografts.

Animals↗
PubMed1992

Induction of specific tolerance to class I-disparate renal allografts in miniature swine with cyclosporine.

Previous studies in miniature swine have suggested that the mechanism underlying the spontaneous development of tolerance in one third of one-haplotype class I disparate renal allografts (i.e., ag----ad) involves a relative T cell help deficit at the time of first exposure to antigen. If this hypothesis were correct, then one might expect the administration of an immunosuppressive agent capable of inhibiting lymphokine production during this period to lead to the induction of tolerance to class I MHC antigens in two-haplotype class I mismatched renal allografts (i.e., gg----dd), which are otherwise uniformly and acutely rejected. This hypothesis was tested in eight two-haplotype class I disparate, class II matched donor-recipient pairs, in which recipients were treated with cyclosporine 10 mg/kg, i.v. q.d. for 12 days. This protocol led to the induction of long-term (greater than 100 days) specific tolerance in 100% of recipients, as compared with control animals that rejected grafts in 13.7 +/- 0.9 days (P less than 0.0001). The specificity of tolerance was assessed both in vivo with subsequent skin grafts and in vitro by mixed lymphocyte response (MLR) and cell-mediated lymphocytotoxicity (CML). Survival of donor-specific skin grafts was prolonged compared with skin grafts bearing third-party class I antigens (19.5 +/- 2.0 versus 11.5 +/- 2.0 days, n = 4, P less than 0.05). Tolerant recipients had markedly diminished or absent anti-donor MLR and CML responses, but maintained normal reactivity to third party. Four of eight CsA-treated recipients showed detectable levels of anti-donor IgM, while none demonstrated the presence of anti-donor IgG, which was found in all rejecting controls.

Animals↗
PubMed1991

Experience with bilateral renal artery stenosis as a cause of hypertension in childhood.

Since 1981, eight children have been treated at this hospital for hypertension due to bilateral renal artery stenosis (RAS). Useful diagnostic studies were DTPA renal scan following pretreatment with captopril, and selective renal angiography. All patients underwent attempted surgical revascularization of the RAS and three had aortoaortic bypass of an abdominal aortic narrowing. Of the 14 kidneys that had repair of RAS, a successful outcome was obtained in 11 (80%). Three patients required unilateral nephrectomy. Five of eight patients are normotensive and off all medications, and three are normotensive on reduced medication doses.

Aortography↗
PubMed1991

Induction of kidney transplantation tolerance across major histocompatibility complex barriers by bone marrow transplantation in miniature swine.

Previous studies from our laboratory have shown that permanent lymphohematopoietic chimerism can be induced in MHC-disparate miniature swine by bone marrow transplantation after lethal total-body irradiation. The purpose of the present study was to determine in this large animal model whether such chimerism would lead to permanent tolerance to a vascularized allograft without a requirement for exogenous immunosuppression. Eight miniature swine that had received MHC-mismatched BMT more than five months earlier underwent kidney transplantation (KTx) from a donor MHC matched (n = 5) or MHC mismatched (n = 3) with the BMT donor. All animals had regained in vitro responsiveness to third-party MHC antigens, as measured by mixed lymphocyte reaction (MLR), before KTx but remained nonresponsive to MHC antigens of the BMT donor and self. All three animals that received KTx mismatched for BMT donor MHC rejected promptly (mean survival time 7.0 days). Of the five animals that received KTx matched for BMT donor MHC, four showed no evidence of rejection and have functioning KTx greater than 200 days after KTx. The fifth animal had excellent renal function for 60 days but then developed a slowly rising BUN and serum creatinine, and died 75 days after KTx. The course of this animal's rejection is consistent with that previously described for rejection due to minor antigen disparities. The difference in survival of KTx matched or mismatched for the MHC of the BMT donor was statistically significant (P = 0.0062). The survival of KTx matched for the MHC of the BMT donor was significantly different from that of control animals without BMT receiving KTx mismatched for MHC (P = 0.0018). We therefore conclude that BMT is an effective means for induction of tolerance to an MHC mismatched KTx in this large animal model.

Animals↗
PubMed1991

The failure of skin grafting to break tolerance to class I-disparate renal allografts in miniature swine despite inducing marked antidonor cellular immunity.

Long-term specific tolerance to one haplotype class I plus minor antigen disparate renal allografts develops without exogenous immunosuppression in approximately 35% of miniature swine (n = 128). Previous studies have suggested that this phenomenon is related to limited class I-specific helper T cell activity as evidenced by the failure of antibody class switching in vivo and the ability of exogenous interleukin 2 to elicit antidonor responses in vitro. To determine whether tolerance could be broken by inducing antidonor reactivity with donor antigen and a source of T cell help, multiple skin grafts bearing donor class I plus third-party class II antigens were placed on tolerant animals. Skin grafts were placed at least 3 months after the kidney transplant, at which time all recipients had normal renal function as measured by blood urea nitrogen and serum creatinine. First-set rejection of skin grafts by SLAad and SLAdd hosts occurred in 11.8 +/- 1.1 days (mean +/- SEM, n = 6) and in 9.3 +/- 0.9 days (n = 4), respectively. Coincident with skin rejection, most animals developed a transient rise in BUN to 62 +/- 11 mg/dl (n = 10) and a similar rise in Cr to 4.9 +/- 1.2 mg/dl (n = 10), with normal levels returning in all animals within two weeks. Subsequent skin grafts with the same disparity did not undergo second-set rejection and did not induce BUN or Cr elevations. Prior to skin grafting, animals showed no antidonor activity in mixed lymphocyte reaction or cell-mediated lymphocytotoxicity assays. After two skin grafts, all animals developed donor-specific CML and secondary MLR responses, and additional skin grafts amplified this cellular immunity. Development of marked antidonor immunity without a break in tolerance suggested that either graft adaptation or local suppression might be involved in maintaining tolerance to class I MHC antigens. In preliminary studies, an immunized SLAad animal and an immunized SLAdd animal were retransplanted with kidneys MHC matched to their first allografts. In both cases, the second graft was accepted permanently without immunosuppression, suggesting that graft adaptation is not necessary for the maintenance of tolerance to renal allografts in miniature swine.

Animals↗
PubMed1990

Restoration of kidney function after prolonged renal artery occlusion.

An 11-month-old child developed renal artery occlusion (RAO) and anuric renal failure following an unsuccessful transluminal renal artery angioplasty of a solitary kidney. Despite the prolonged period of anuria, kidney viability was suspected based upon preservation of kidney length and the absence of glomerulosclerosis. At 19 months of age, revascularization of the kidney was performed. During the 7 months following revascularization, renal function gradually improved so that dialysis was no longer necessary. This improvement occurred in spite of significant tubular atrophy. Kidney viability may have been preserved, despite prolonged ischemia, as a result of the decreased renal oxygen consumption that existed during subfiltration glomerular perfusion pressures. The low normal blood erythropoietin level may have reflected the lack of renal hypoxia. The ability of the kidney to adapt to chronic ischemia underscores the importance of considering vascular reconstruction in all patients with RAO despite a long period of non-function.

Humans↗
PubMed1990

Transplantation in miniature swine: analysis of graft-infiltrating lymphocytes provides evidence for local suppression.

Previous studies from this laboratory have demonstrated that swine tolerant of class I disparate renal allografts show peripheral antidonor cellular reactivity which can be augmented by skin grafting. To assess the possibility of local suppression, cell-mediated lymphocytotoxicity of graft-infiltrating lymphocytes was compared to that of peripheral blood lymphocytes from three tolerant and four acutely rejecting recipients of class I--disparate renal allografts. Mixed lymphocyte cultures using peripheral blood lymphocytes or graft-infiltrating lymphocytes and an equal number of irradiated peripheral blood lymphocyte stimulators were incubated for 6 days and tested in a 6-hr 51Cr release assay. Graft-infiltrating lymphocytes from rejecting animals had potent antidonor cell-mediated lymphocytotoxic activity with or without in vitro stimulation. Anti-third-party reactivity was seen with appropriate stimulation, suggesting heterogeneity of graft-infiltrating lymphocyte cultures. Peripheral blood lymphocytes from rejectors generated donor-specific cell-mediated lymphocytotoxicity. Graft-infiltrating lymphocytes from tolerant animals generated no antidonor cell-mediated lymphocytotoxicity with or without in vitro stimulation, but generated an anti-third-party response. Peripheral blood lymphocytes from tolerant animals displayed both antidonor and anti-third-party reactivity with appropriate in vitro stimulation. These data support the hypothesis that local suppression may contribute significantly to maintenance of tolerance to class I disparate renal allografts in miniature swine.

Animals↗
PubMed1990

Patterns of injury in children.

Trauma is the leading cause of death for children over 1 year of age. This study was undertaken to identify the patterns of injury among children admitted to a regional pediatric trauma center. During a 34-month period, 3,472 injured children were consecutively admitted to a regional pediatric trauma center. Data were collected on medical, etiological, and financial aspects of injury. Eight subgroups were defined by mechanism of injury: motor-vehicle crash occupants, pedestrian and cycle injuries, falls, child abuse, gunshot and stab wounds, burns, poisonings, and foreign body ingestions or aspirations. Analysis of variance, Duncan's multiple range test, and contingency table analysis were used to determine differences among subgroups of children. Blunt and penetrating trauma accounted for 64.3% of all admissions. The mean age of injured children was 5.5 years; 64% of the children were boys. Sixty-seven percent of the children were admitted directly from the scene of injury. One-way analysis of variance yielded significant differences in mean age, mean hospital length of stay (LOS), mean intensive care LOS, mean trauma score, mean injury severity, and mean hospital charges by mechanism of injury (P less than .01). The overall mortality rate was 2.4%. Child abuse, gunshot/stab wounds, and drowning had the highest mortality rates, but injuries to motor-vehicle crash occupants and pedestrians accounted for the greatest number of deaths.

Accidental Falls↗
PubMed1990

Elective subtotal splenectomy. Indications and results in 33 patients.

Elective subtotal splenectomy was performed in 33 patients (30 children and 3 adults) between 1981 and 1989. Indications for the procedure were (1) prevention of azathioprine-induced neutropenia (n = 20); (2) Type I Gaucher disease (n = 9); and (3) cholesteryl ester storage disease, chronic myelogenous leukemia, thalassemia major, and splenic cyst in one patient each. There were no operative deaths, no reoperations for bleeding, and 30 of 33 (91%) patients had a functioning splenic remnant documented by a postoperative radionuclide spleen scan. One patient developed neutropenia without evidence of viral infection that required temporary cessation of azathioprine and the patient with thalassemia major had only transient improvement in transfusion requirements. All other patients (94%) had control of the underlying condition for which the operation was performed. We conclude that subtotal splenectomy is a safe, effective therapy for a variety of nontraumatic conditions.

Adolescent↗
PubMed1990

Mechanism of tolerance following class I--disparate renal allografts in miniature swine. Cellular responses of tolerant animals.

Previous studies utilizing a recombinant MHC haplo-type in our partially inbred miniature swine herd have demonstrated that some recipients matched only for SLA class II show long-term acceptance of renal allografts without exogenous immunosuppression. Such animals have been shown to develop systemic tolerance as evidenced by prolonged rejection times of subsequent donor-specific, but not third-party, skin grafts. In the present studies in vitro cellular responses of long-term tolerant animals and of 7 animals studied sequentially are presented. Long-term tolerant animals demonstrated responses consistent with the absence of the class I reactive helper populations normally present in naive controls. Animals studied sequentially segregated into two groups based on cellular reactivity and survival. All animals showed complete loss of antidonor class I cell-mediated lymphocytolytic (CML) reactivity by postoperative day 10. However, animals surviving less than 20 days maintained CML reactivity to donor class I plus third-party class II in the posttransplant period, while animals surviving greater than 40 days lost such reactivity. Addition of exogenous interleukin 2 could not reverse this loss. These studies suggest that tolerance induction to a renal allograft across a class I only difference involves effects on both helper and killer class I reactive cell populations.

Animals↗
PubMed1989

Successful management of aberrant subclavian artery-esophageal fistula in an infant.

This report describes a 4-month-old female infant with complex congenital heart disease and prolonged nasogastric intubation who developed an aberrant subclavian artery-esophageal fistula that was successfully managed in a two-staged procedure. To our knowledge, this is the first patient to survive correction of this problem after massive hemorrhage.

Esophageal Fistula↗
PubMed1989

Malignant mesenchymoma of the liver in children.

Four children, aged 5 to 13 years, were treated for malignant mesenchymoma of the liver. Two survived longer than 5 years with complete resection and adjuvant chemotherapy. Two children who had incomplete resection with microscopic residual mesenchymoma both had tumor recurrence and died of disease progression despite radiation therapy and chemotherapy. Although previous reports emphasize a poor prognosis for children with this tumor, our experience would indicate that long-term survival can be achieved using complete surgical extirpation and adjuvant chemotherapy.

Adolescent↗
PubMed1989

Renovascular hypertension in children: current concepts in evaluation and treatment.

Since 1981, we have evaluated and treated 22 children with renovascular hypertension (RVH). Seventeen patients had stenosis of their native renal arteries, and five had stenosis of the artery in a transplanted kidney. RVH was caused by fibromuscular dysplasia in 13 patients, by trauma in 2 patients, and by arteritis in 2 patients. Among the patients who had transplanted kidneys, three had technical causes for stenosis and two had stenosis due to rejection. The disease was unilateral in 10 patients, bilateral in 5, and present in a solitary kidney in 7, including the five renal transplants. Diagnostic studies that strongly suggested the presence of renovascular disease were an initial diastolic blood pressure greater than 100 mm Hg, an elevated peripheral vein renin activity level, and an abnormal renal scan if the patient's hypertension was being controlled with an angiotensin-converting enzyme inhibitor (ACEI). Only the renal arteriogram was 100% accurate in confirming the presence of RVH. Percutaneous angiographic correction was attempted in 13 patients and resulted in lasting improvement of the hypertension in five (38%). Surgical revascularization was attempted in 17 children, including the 8 with failed angioplasty, with improvement or cure of the hypertension in 15 patients (88%). Combining percutaneous transluminal angioplasty (PTA) and surgical results gave 20 of 22 patients (91%) with cure or improvement of their hypertension. Four of 27 affected kidneys (15%) could not be revascularized and were removed. We conclude from this series of patients that despite improvements in noninvasive studies, renal arteriogram remains the only study that is 100% accurate in evaluating children for RVH.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Pediatric hepatic surgery.

Tumors of the liver are uncommon in children. It is imperative that surgeons caring for these patients have a knowledge of the likely diagnosis, proper radiographic evaluation, and appropriate selection and extent of surgical therapy. Of the benign lesions, infantile hemangioendothelioma often is best treated nonoperatively, whereas mesenchymal hamartoma and teratoma should be resected. All malignant lesions must be completely excised to cure the patient, but some may be converted from unresectable tumors to resectable ones by preoperative chemotherapy. Major hepatic resection is one of the most formidable procedures in the surgery of children. Careful preparation, attention to technical detail, and precise postoperative management of the critically ill child are prerequisites for success. For a recent review of the extrahepatic biliary tract problems of infants and children, the reader is referred to the article by Stolar and Altman in Surgical Clinics of North America, Volume 65, October 1985.

Carcinoma, Hepatocellular↗
PubMed1987

Operative technique and results of subtotal splenectomy for Gaucher disease.

Patients with type 1 (adult form) Gaucher disease complicated by massive splenomegaly and hypersplenism have previously been treated by total splenectomy. Subtotal splenectomy in Gaucher disease will retain splenic tissue which may protect the patient from the risk of overwhelming sepsis. Removal of at least 85 per cent of the splenic mass is necessary to eliminate hypersplenism and to decrease splenic size. The surgical technique and outcome of four patients undergoing subtotal splenectomy for massive splenomegaly due to type 1 Gaucher disease are discussed.

Adult↗