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P Hayry

Publications and source records attributed to P Hayry.

13 recordsLinked to original sources
PubMed2001

Estrogen receptor beta dominates in baboon carotid after endothelial denudation injury.

Increasing evidence, mainly from rodents, suggests that the predominant estrogen receptor (ER) in arteries is the newly-described ERbeta. We have investigated the expression of the two ERs in baboon carotid artery before and after denudation injury. Prior to denudation, both full length receptors were detected in semiquantitative RT-PCR; in addition two ERalpha but no ERbeta splicing variants were found. After denudation, ERbeta mRNA increased five-fold and declined, whereas ERalpha mRNA expression remained low. Prior to and after denudation, two ERalpha-specific antibodies showed no reaction with the vessel wall. Instead, two affinity purified antisera to ERbeta demonstrated a weak but distinct reaction over vascular smooth muscle cells with predenudation specimens, escalating post-denudation and declining thereafter. The results suggest that selective targeting to ERbeta should be attempted when designing estrogen-based vasculoprotective drug therapies devoid of uterotrophic side effects.

Alternative Splicing↗
PubMed1999

Differential regulation of somatostatin receptor types 1-5 in rat aorta after angioplasty.

Treatment of restenosis after angioplasty with octapeptide somatostatin (SST) analogs has met with variable success. These analogs bind with high affinity to only two SST receptor (SSTR) subtypes (2 and 5), display moderate affinity for SSTR3, and low affinity for SSTR1 and 4. To optimize the vasculoprotective effect of SST, we have investigated the pattern of expression of all five SSTRs in rat thoracic aorta in the resting state and at 15 min, 3, 7, and 14 days after balloon endothelial denudation. SSTR1-5 were analyzed as mRNA by semiquantitative reverse transcriptase-polymerase chain reaction and as protein by immunocytochemistry. All five SSTRs were expressed in rat aorta both as mRNA and protein and displayed a time-dependent, subtype-selective response to endothelial denudation. mRNA for SSTR1 and 2 increased acutely (SSTR1 > SSTR2) on days 3 and 7, coincident with smooth muscle cell (SMC) proliferation, and declined to basal levels by day 14. SSTR3 and 4 displayed a different pattern with a delayed, more gradual increase in mRNA beginning at days 3-7 and continued to increase thereafter. SSTR5 mRNA was constitutively expressed at a low level and showed no change during the 2 wk postinjury period. By immunohistochemistry, SSTR1-5 antigens were localized predominantly in SMC that were present in the media or had migrated into the intima; antigen expression correlated with receptor mRNA expression. Notably, only SSTR1,3,4 were expressed in the intima: SSTR1 and 4 during the proliferative burst and SSTR3 and 4 after proliferation, when SMC migration into the intima continues. These results demonstrate dynamic changes in SSTR1-5 expression after vascular trauma localized to areas of vascular SMC migration and replication. In view of their early and prominent induction, SSTR1 may be the optimal subtype to target for inhibition of myointimal proliferation, and SSTR3 and 4 for migration and remodeling.

Angioplasty, Balloon↗
PubMed1989

Major histocompatibility complex protein expression on pancreas and pancreatic islet endocrine cell subsets.

To determine which cells in the human and rat pancreas and islets express class I and II histocompatibility complex proteins, double indirect immunofluorescence and the Staphylococcus aureus rosette method were used. Islet preparations used permitted positive endocrine and class I or II protein identification. Class I and II proteins were expressed in pancreatic vascular endothelium and passenger cells of the mononuclear cell type. Antibodies directed to class I or beta 2 microglobulin reacted with dispersed islet B, A, and D cells, whereas class II protein antibodies were associated with only islet B and A cells. Islet B-cell class II proteins decreased after 20 days of in vitro culture. These results suggest that 1) a variety of pancreas and islet nonendocrine cells can express class I and II proteins, 2) normal pancreatic islet endocrine cells not only express class I proteins but also class II proteins, and 3) in vitro islet culture results in reduced expression of class II proteins by islet B cells.

Animals↗
PubMed1987

Allospecific rat-mouse T hybridoma clones generated from kidney graft-infiltrating cells.

In order to dissect the cellular mechanisms that lead to allograft rejection, infiltrating cells can be isolated and expanded in vitro for functional assays. Since the maintenance of these lines and clones is time-consuming, and large numbers of specific cells cannot be easily obtained, we fused the graft infiltrating cells, after in vitro specific expansion, with the murine T lymphoma BW5147. The rat-mouse TT hybridomas thus generated were screened for antigen-dependent interleukin 2 production, for antigen-dependent polyclonal helper activity, and for surface phenotype. The high frequency of specific clones obtained indicates that this is a convenient approach to generate alloreactive hybridoma clones with specific functions from the inflammatory infiltrates of rejected grafts.

Animals↗
PubMed1982

Redistribution of renal allograft-responding leukocytes during rejection. II. Kinetics and specificity.

We investigated the traffic of allograft-responding leukocytes between the host and graft without handling of these cells in vitro. The blood flow between the host and graft was disconnected, the proliferating cells were labeled with [3H]thymidine selectively in the graft or in the host, the label was chased with cold thymidine, and the circulation was reestablished. The localization of labeled cells was quantitated by autoradiography. The first host-derived labeled cells appeared in the graft and graft-derived labeled cells in the host, already on the 1st d after transplantation. This was followed by an exponential increase in the labeled cell traffic in both directions. The peak of traffic was observed on day 4 after transplantation, whereafter the traffic rapidly declined and tapered off. This decline was not due to exhaustion of supply, as the labeled cells continued to proliferate in their original compartments, nor to a slowdown of blood circulation, which took place 2-3 d later. We consider the decline to indicate that the rejection has proceeded to a (irreversible) stage autonomous of the host lymphatic and hematopoietic system. During the exponential increase, nearly one-third of the graft-infiltrating inflammatory cells were replaced as a consequence of relocalization during each 18-h-period. All mononuclear white cell types, with the exception of granulocytes, participated in the traffic. Most lymphoid cells entrapped in the graft were descendents of recent cell divisions; most of the mononuclear phagocytes derived from a preexisting phagocyte pool. The entrapment of labeled leukocytes in a relevant graft was specific: when an allograft and an autograft were simultaneously transplanted, a more than 50-fold entrapment was observed in the allograft, compared with the autograft. Very few of the cells localized in irrelevant positions, such as the liver and lung, of the recipient.

Animals↗
PubMedDate not supplied

Protocol core needle biopsy and histological chronic allograft damage index as surrogate endpoint for Long-Term graft survival.

Following encouraging results from several single-center studies showing that early histological manifestations of chronic rejection are seen in the graft before a decline in transplant function, we tested this concept in a multicenter study and investigated whether protocol needle biopsy may be used as a surrogate to late graft survival in multicenter renal transplantation trials. During two mycophenolate mofetil trials, 621 representative protocol biopsies were obtained at baseline, 1 year, and 3 years. The samples were coded and evaluated blindly by two pathologists and a Chronic Allograft Damage Index (CADI) score was constructed. At 1 year only 20% of patients had elevated (>1.5 mg/100 mL) serum creatinine, whereas 60% of the biopsies demonstrated an elevated (>2.0) CADI score. The mean CADI score at baseline, 1.3 +/- 1.1, increased to 3.3 +/- 1.8 at 1 year and to 4.1 +/- 2.2 at 3 years. The patients at 1 year were divided into 3 groups, those with CADI <2, between 2 and 3.9, and >4.0, the first two groups having normal (1.4 +/- 0.3 and 1.5 +/- 0.6 mg/dL) and the third group pathological (1.9 +/- 0.8 mg/dL) levels of serum creatinine. At 3 years there were no lost grafts in the "low" CADI group, six lost grafts (4.6%) in the "elevated" CADI group, and 17 lost grafts (16.7%) in the "high" CADI group (P <.001). One-year histological CADI score predicts graft survival even when the graft function is still normal. This observation makes it possible to use CADI as a surrogate endpoint in prevention trials and to identify the patients at risk for intervention trials.

Biopsy, Needle↗