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Biomedical subjects

J Ahonen

Publications and source records attributed to J Ahonen.

At least 163 records · Page 9Linked to original sources
PubMed1986

CMV infection, class II antigen expression, and human kidney allograft rejection.

After successful transplantation, the major histocompatibility complex (MHC) antigens of kidney parenchymal cells are lost and no longer detectable in the graft, presumably due to administration of glucocorticosteroids. During rejection, the MHC antigens reappear in the graft parenchymal cells. The upregulation is possibly due to gamma-interferon released in situ by the allograft activated T (blast) cells. In this communication we demonstrate that cytomegalovirus (CMV) infection is invariably associated with an upregulation of the antigen display in the graft. In 12 of 14 (86%) cases with proved CMV disease, the display of class II antigens was associated with a cytological and/or clinical episode of rejection. In 223 transplant recipients without proved CMV disease transplanted during the same period, the frequency of late rejections was 17% (P less than 0.001). The results suggest that the display of class II antigens on the graft, mediated presumably by gamma-interferon as a consequence of CMV infection, is the reason for graft rejection in context of CMV disease.

Cytomegalovirus Infections↗
PubMed1986

Renal transplantation in 45 patients with amyloidosis.

The results of renal transplantation in patients with amyloidosis were studied in 45 patients receiving primary cadaver grafts at a single center between March 1973 and October 1981. A control group of 45 patients with glomerulonephritis receiving primary cadaver grafts during the same period was also studied. These were matched according to the number of A and B locus incompatibilities and the date of transplantation. The 3-year survival of the patients with amyloidosis was statistically significantly inferior (51%) to that of the controls (79%). Age over 40 years was the major factor determining low survival in these patients. Mortality was concentrated in the early posttransplantation period. The 3-year graft survival rate was the same in amyloidotics (38%) and controls (45%); with death of patients not included in graft loss, the corresponding figures were 53% and 49%. Appearance of amyloid in the transplant was established by biopsy in four patients at 11-37 months of follow-up. Renal transplants functioning for more than one year were calculated to incur a minimum risk of 20% of acquiring amyloid.

Adult↗
PubMed1986

The prognostic significance of radiologically determined gastric emptying time before proximal gastric vagotomy.

The importance of undisturbed pyloric function is known among surgeons applying proximal gastric vagotomy (PGV) for duodenal ulcer disease. On the other hand, the prognostic significance of subclinically impaired antroduodenal motility is unknown after this operation. Therefore, in the present study 43 PGV patients with normal gastric emptying were compared with 24 PGV patients with prolonged gastric emptying as to the postoperative incidence of ulcer recurrence and symptomatology. Prior to surgery gastric emptying time was determined radiologically in all patients, none of whom had symptoms or signs of gastric outlet obstruction. The duration of postoperative follow-up in the series was 8 to 11 years. The incidence of ulcer recurrence during follow-up was 16% in the whole series, being significantly higher among patients with the primary ulcer in the pyloric or prepyloric area than among those with the lesion in the duodenal bulb. Furthermore, in the patient group with a primary ulcer in the duodenum an excellent operation result was achieved significantly more frequently in the case of preoperatively normal gastric emptying than in the case of delayed emptying. The incidence of ulcer recurrence tended also to be higher among the duodenal ulcer patients with prolonged emptying than among those with normal emptying through the difference between the groups did not reach statistical significance. This study emphasizes the prognostic significance of unimpaired gastric emptying and of even minor subclinical motor dysfunction when electing PGV as the surgical treatment and also that radiologic determination of gastric emptying time before PGV is of value in all patients undergoing the operation, irrespective of the location of the primary ulcer.

Adult↗
PubMed1985

Prophylactic oral acyclovir after renal transplantation.

In a double-blind, controlled study 35 herpes simplex virus (HSV) antibody-positive patients were randomized to receive oral acyclovir 200 mg X 4 daily or placebo for 28 days following renal transplantation. The incidence of herpes virus infection was compared in both groups by weekly virus demonstration/isolation testing from throat swabs and urine, and by serum antibody demonstration. None of the 18 patients allocated to acyclovir showed any signs of HSV or varicella zoster virus (VZV) infection during the trial period, whereas 9 of 17 receiving placebo had signs of HSV (P less than 0.001) and 2 of VZV (P less than 0.05) infection. Because of systemic as well as local symptoms of infection in five of the placebo patients, the trial was interrupted and treatment with oral acyclovir instituted. All of them responded well with rapid disappearance of all symptoms. Cytomegalovirus (CMV) was isolated from the urine of two patients in both groups during the trial period; a significant antibody rise was seen later in three of them. There was no evidence of drug-related toxicity during the study.

Acyclovir↗
PubMed1985

Relation between serum group II pepsinogen concentration and the degree of Brunner's gland hyperplasia in patients with chronic renal failure.

Serum concentrations of group I and II pepsinogens (PG I and PG II) were determined in 15 patients with chronic renal failure. Gastroduodenoscopy with biopsy and acid secretion tests were also performed. Five patients had histologically confirmed severe Brunner's gland hyperplasia manifesting as multiple polyps in the duodenal bulb. Five patients had a mild form of Brunner's gland hyperplasia which was evident only by histological analysis. Five had no signs of such alterations. The three groups of patients were comparable in age, sex, mean level of serum creatinine, mean duration of dialysis treatment, distribution of non-dialysed and dialysed patients, and gastric histology. In patients with severe Brunner's gland hyperplasia the mean serum PG II concentration was significantly higher than in the other patients. Both the serum PG I and the serum PG II concentrations decreased after receiving a well functioning renal transplant in the two patients who underwent transplantation.

Adult↗
PubMed1985

The effect of renal transplantation on gastric acid secretion and on the serum levels of gastrin and group I pepsinogens.

To gain further understanding of the peptic complications encountered in renal transplant surgery, 84 patients (19 with chronic renal failure on dietary treatment, 29 on regular dialysis treatment, 36 with a well-functioning renal transplant) were studied with regard to gastric acid secretion capacity and serum concentrations of gastrin and group I pepsinogens (PG I). The mean duration of preoperative dialysis treatment of the dialysed patients was 13.7 months. The mean length of postoperative follow-up of the transplant patients was 10.1 months. There was no significant difference between the mean gastric acid secretion of the three groups of patients. All the means were within the reported reference interval for healthy controls. However, 26% of the non-dialysed, 17% of the dialysed and 28% of the transplant patients had gastric hyposecretion. The mean serum concentration of gastrin was elevated in all patient groups and unaffected by normalization of renal function through transplantation, unlike PG I, which was normalized by the procedure. Thus, in the present era of treatment of chronic renal failure with a relatively short period of dialysis treatment, the frequent gastric hypoacidity, which is known to be peculiar to non-dialysed uraemic patients, seems also to characterize dialysis and transplant patients.

Adult↗
PubMed1985

Acyclovir and renal transplantation.

The efficacy of oral acyclovir to prevent reactivation of herpes simplex virus (HSV) in seropositive renal allograft recipients was tested in a double-blind placebo controlled study. None of the 18 patients allocated to acyclovir showed any signs of HSV infection. In contrast, 11/17 on placebo (p less than 0.001), had signs of HSV or varicella zoster virus (VZV) infection--in 5 patients severe enough to interrupt the trial and initiate treatment with oral acyclovir. Soon after cessation of the trial, HSV was isolated from the throats of 6 patients on acyclovir, and 1 developed shingles 3 months later. Oral acyclovir prophylaxis thus effectively protected the patients from reactivation of HSV and VZV while they were receiving the drug, but could not prevent disease once off the drug. Treatment with acyclovir brought rapid relief of both local and general symptoms in all patients. No adverse reactions were seen. As a consequence of these experiences our goal in subsequent transplant patients has been either early therapeutic intervention with oral acyclovir whenever signs of HSV or VZV infection have been noted, or prophylactic remedy in patients at particular risk to develop troublesome herpetic lesions after renal transplantation.

Acyclovir↗
PubMed1984

Measurement of serum amyloid A protein concentrations as test of renal allograft rejection in patients with initially non-functioning grafts.

Serum amyloid A protein concentrations were monitored in 10 renal transplant recipients who required dialysis after transplantation because of an initially non-functioning graft. Fifteen rejection episodes were identified by repeated fine needle aspiration biopsies of the grafts. All rejections were characterised by pronounced increases in serum amyloid A concentrations, the mean peak value being 363 (SE 57) mg/1 as compared with a mean preoperative concentration of 14 (5) mg/1. The rise in concentrations preceded the start of anti-rejection treatment by an average of 2.5 days in eight of the rejection episodes, in five episodes it occurred the same day, and in two episodes it occurred the next day. With exclusion of the predictable surgery induced rise in values, which peaked on the second postoperative day, there were 17 increases in amyloid A concentrations peaking at greater than or equal to 100 mg/1; in two cases they were not related to documented rejection. These findings show that measurements of serum amyloid A concentration provide a valuable non-invasive aid in identifying acute renal allograft rejection, including that in patients whose graft does not function initially.

Adult↗
PubMed1984

Fine-needle aspiration cytology of liver allografts in the pig.

We have analyzed the inflammatory changes in pig liver allografts and autografts by fine needle aspiration biopsy (FNAB) and correlated the cytological findings with transplant histology and changes in recipient blood. In nonimmunosuppressed piglets (n = 9) the inflammatory episode of rejection occurred promptly, peaked on days 4-7, and thereafter subsided in cases in which the graft was accepted (n = 6). The early inflammatory infiltrate consisted of all major types of inflammatory leukocytes, including T lymphoblasts, B plasmablasts, and plasma cells, lymphocytes and monocytes; macrophages dominated the late inflammatory lesion of irreversible rejection. In piglets that died of rejection (n = 3), the inflammation peaked earlier and the total amount of inflammation, including the frequency of blast cells and mononuclear phagocytes, was higher. These differences were, however, statistically insignificant and not predictive for irreversible rejection. In sham-operated autograft recipients (n = 5) no inflammation was recorded in the graft. Application of cyclosporine (n = 5), significantly suppressed the total inflammation (P = 0.02 and 0.06 on days 4 and 7, respectively) and delayed the peak; in addition, both the blastogenic component (P = 0.08 on day 4) and the mononuclear phagocyte component (P = 0.03 on day 7) were clearly suppressed. These inflammatory changes, recorded by the FNAB, had a close correlation with biopsy histology. On the other hand, determinations of S-ASAT, S-ALAT, and S-AFOS was not correlated with the episodes of rejection, and no characteristic changes were seen in blood cytology during the rejection episodes either.

Animals↗
PubMed1984

Cytotoxic T cells recognizing minor transplantation antigens, and possibly a variant of the HLA-B8 molecule. Cause of rejection of an HLA-identical sibling kidney transplant?

A male uremic patient was first transplanted with a kidney from a female cadaveric donor. The kidney was rejected after two weeks. He was retransplanted approximately one year later with a kidney from his HLA-identical sister. This graft was also irreversibly rejected after one week. No serum antibodies could be detected against the sibling donor before or after transplantation, but the recipient had formed donor-specific cytotoxic T lymphocytes (CTLs). The CTLs were cloned, and clones with two different specificities were obtained. One clone lysed target cells from the donor, from some other family members, and from 50% of a panel sharing HLA-B15 with the recipient. It may recognize a minor transplantation antigen, that is restricted by HLA-B15. The other clone lysed target cells from the donor, from all HLA-B8-positive family members (except the recipient), and from third-party cell donors sharing HLA-B8 with the recipient. When CTLs from third-party individuals were induced toward HLA-B8, target cells from all HLA-B8-positive family members were lysed, except those from the recipient. This indicates that the recipient may have inherited a variant of HLA-B8 that is not detectable by antibodies but by CTLs. These donor-specific CTLs may have contributed to the rejection of the HLA-identical sibling transplant.

Adult↗
PubMed1984

Angiotensin I-converting enzyme inhibition after renal transplantation.

The angiotensin I-converting enzyme inhibitor captopril was administrated to 15 renal transplant patients for a minimum period of 14 weeks after transplantation. The object was to decrease ischaemic damage caused by secondary activation of the renal renin-angiotensin system after rejection and associated vascular damage. Captopril patients had lower s-creatinine values than controls in the immediate phase after rejection. On the other hand, after 14 weeks renal perfusion was better, but glomerular filtration rate lower in the captopril group than in the control group. However, none of the differences were significant. Renal function was examined during captopril administration, which may have affected the results. Final evaluation of this trial requires extended follow-up. Captopril was well tolerated in the low doses used (37.5-75 mg daily) in spite of varying degrees of renal failure and concomitant azathioprine administration. Only one case of mild leukopenia was recorded, which improved immediately after captopril interruption. No other serious side effects were observed. Captopril may be safely administered to renal transplant patients, if monitoring of renal function and possible side effects is carried through.

Adult↗
PubMed1984

Glucocorticosteroids in renal transplantation. II. Impact of high- versus low-dose postoperative methylprednisolone administration on graft survival and on the frequency and type of complications.

In a previous clinical trial we demonstrated that, by increasing the postoperative administration of methylprednisolone from 1.0 to 3.5 mg/kg/day, the onset of the first inflammatory rejection episode was significantly delayed and the size of the inflammation was reduced. The 'high initial' steroid treatment specifically depleted blast cells and macrophages from the in situ inflammatory infiltrate. In this trial we demonstrate that the 'high initial' glucocorticosteroid administration significantly improves 1-year cadaver allograft survival from 44% to 68% (P = 0.003) without increasing the number of complications. Although the 'high initial' steroid administration only partially overcomes the impact of HLA-AB incompatibility, it seems to overcome entirely the impact of absence of blood transfusions. The 'high initial' steroid administration also makes the first episodes of inflammation easier to overcome: less steroids are needed to counteract the first rejection, and, as a consequence, only 30% more steroids were used in the 'high initial' versus the 'low initial' steroid programme.

Blood Transfusion↗
PubMed1984

Aspiration cytology of a human liver allograft.

We have analyzed one human liver transplant by frequent FNABs. We conclude that FNABs of liver transplant recipients is a safe procedure that can be performed repeatedly without danger to the graft or to the graft recipient. The inflammatory episodes of rejection may be recorded and certain changes in the transplant--in particular, cholestasis and deposits of CsA--may be demonstrated in the FNAB as well.

Adult↗
PubMed1984

The effect of relative bowel rest on healing of colonic anastomoses. Collagen synthesis and content in the colonic wall after left colon resection and anastomosis in the rat.

Collagen metabolism was studied in the colonic wall of rats after standardized resection and anastomosis. Diminished faecal loading was obtained by feeding rats low-residue diet (Bisorbin MCT). The postoperative increase of collagen synthesis and collagen content was on a lower level in these rats than in rats on standard laboratory diet. The increase was confined to the immediate anastomotic region and presumably represented changes in collagen caused by the operative trauma per se. It was concluded that the intraluminal content is an important factor in stimulating collagen turnover. The findings of lower collagen turnover in the anastomotic area in animals on low-residue diet may have positive significance, but could also imply impairment of healing. For elucidation of this question, studies on mechanical strength of the anastomosis are necessary.

Animals↗