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Biomedical subjects

P Buxbaum

Publications and source records attributed to P Buxbaum.

35 records · Page 2Linked to original sources
PubMed1989

Characteristics of 308 nm excimer laser activated arterial tissue photoemission under ablative and non-ablative conditions.

The present study was designed to assess the characteristics of tissue photoemission obtained from normal and atherosclerotic segments of human postmortem femoral arteries by 308 nm excimer laser irradiation of 60 ns pulsewidth. Three ablative (20, 30, and 40 mJ/pulse) and three non-ablative (2.5, 5, and 10 mJ/pulse) energy fluences were employed. Both the activating laser pulses and the induced photoemission were guided simultaneously over one and the same 1,000 micron core optical fiber that was positioned in direct tissue contact perpendicular to the vascular surface. The spectral lineshape of normal arterial and noncalcified atherosclerotic structures was characterized by a broad-continuum, double-peak emission of relevant intensity between wavelengths of 360 and 500 nm, with the most prominent emission in the range of 400-415 (407 nm peak) and 430-445 nm (437 nm peak). Fibrous and lipid atherosclerotic lesions, however, exhibited a significantly reduced intensity at 437 nm compared to normal artery layers (P less than 0.001), expressed as a 407/437 nm ratio of 1.321 +/- 0.075 for fibrous and 1.392 +/- 0.104 for lipid lesions. Normal artery components presented with approximately equal intensity at both emission peaks (407/437 nm ratio: intima, 1.054 +/- 0.033; media, 1.024 +/- 0.019; adventitia, 0.976 +/- 0.021). Comparison of spectral lineshape obtained under various energy fluences within a group of noncalcified tissues disclosed no substantial difference using the 407/437 nm ratio (P greater than 0.05). In contrast, calcified lesions revealed high-intensity multiple-line (397, 442, 461, and 528 nm) emission spectra under ablative energy fluences, whereas a low-intensity broad-continuum, single-peak spectrum resulted from irradiation beyond the ablation threshold. Thus, these findings suggest fluorescence phenomena for broad-continuum spectra, and plasma emission for multiple-line spectra as an underlying photodynamic process. Regardless of the activating energy fluence, spectral analysis of 308 nm activated photoemission provides accurate information about the laser target under standardized in vitro conditions. It is demonstrated that direct contact ablation and simultaneous spectral imaging of the target tissue via the same optical fiber is feasible.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1989

1,2-Dimethylhydrazine-induced carcinogenesis influenced by different colonic anastomoses in rats.

Dispensing subcutaneously 1,2-dimethylhydrazine, intestinal carcinogenesis was investigated in male Fisher rats with different surgical colonic anastomoses, producing blind gut loops of isoperistaltic high (fecal stasis) and anisoperistaltic low fecal contact. One hundred and eight rats, except 1 rat of the control group, developed colonic neoplasms. In contrast to the control group, mainly in anastomotic areas and in isoperistaltic blind gut loops with intensive fecal contact huge adenocarcinomas of exophytic growth appeared with a mean tumor diameter (MTD) of 1.9 +/- 0.7 to 2.2 +/- 0.8 cm. Even in the control group, where rats only underwent laparotomy, we observed small polypoid adenocarcinomas mainly located in the distal colon (MTD: 0.7 +/- 0.3 cm). Anastomotic areas and isoperistaltic blind loops with intensive fecal contact proved to be regions with a higher risk for carcinoma formation.

1,2-Dimethylhydrazine↗
PubMed1989

Independent risk factors predicting acute graft rejection in cardiac transplant recipients treated by triple drug immunosuppression.

To assess independent risk factors predicting the occurrence of clinically significant acute rejection episodes in the first 6 months after cardiac transplantation, we performed a multivariate stepwise logistic regression analysis. Forty-three recipients, undergoing transplantation between September 1986 and May 1988, were eligible for analysis and received standardized, low-dose triple drug maintenance immunosuppression with cyclosporine, azathioprine, and prednisolone. Immunoprophylaxis was supplemented perioperatively with either a polyclonal (antithymocyte globulin, N = 26) or a monoclonal (OKT3, N = 17) anti-T-cell antibody. Investigated, conceivable risk factors comprised recipient and donor age, ischemic time, perioperative anti-T-cell antibody prophylaxis, recipient preoperative status, underlying disease, previous cardiac operation, and histocompatibility parameter (mismatches for HLA-A, HLA-B, HLA-DR, HLA-B+DR, HLA-A+B+DR, and Rh0[D] antigen, HLA-DRw6 positive recipient, and identify for ABO system). Univariate analysis suggested significant influence of the type of antibody used perioperatively (p = 0.0024) and the number of mismatches for HLA-A+B+DR (p = 0.0037) and for HLA-B+DR (p = 0.0043). Stepwise logistic regression yielded the number of mismatches for HLA-B+DR (p = 0.0029) and the type of antibody used perioperatively (p = 0.0031) as being highly significant predictors of acute cardiac rejection. Six-month freedom from rejection was 100%, 41%, and 27% for recipients with two, three, and four mismatches for HLA-B+DR and 59% versus 22% for recipients with polyclonal versus monoclonal antibody prophylaxis. Similar to results with kidney transplantation, these results indicate that a poor donor/recipient match for combined HLA-B+DR loci constitutes an independent risk factor for acute graft rejection in low-dose triple drug immunosuppressed cardiac recipients, which stimulates the potential concept of prospective HLA matching. In our experience OKT3 prophylaxis provides significantly less effective prevention of acute rejection than a comparable course of antithymocyte globulin.

Acute Disease↗
PubMed1988

[Experimental bile duct replacement using deep seromuscular stomach wall grafts].

Numerous materials and experimental designs were tested hitherto concerning their usefulness as a substitute of the ductus choledochus. However, an ideal substitute to discover failed. We had tested a serous muscular stomach wall patch, flapped at the gastroepiploic vasa, in 6 pigs. Choledochus epithelium did not grow in every case. A scarred shrinking with following stenosis of the transplant resulted in all cases with a longer observation period. We concluded from that a serous muscularly flapped stomach wall transplant does not suit as a bile duct substitute.

Animals↗
PubMed1988

Pathology of renal cancer and its metastases.

The pretherapeutic classification of renal carcinomas includes the assessment of the tumor stage, the histological gross pattern, the cytological features, and the histopathological grading. As to the local tumor extension the perinephric invasion and renal vein involvement are the most important prognostic features. The presence of metastases dramatically alters survival. Histologically, compact, tubular, and papillary growth patterns are differentiated. Furthermore, the verification of the cell types in renal carcinomas is of prognostic significance. The clear cell carcinomas are opposed to the granular cell and spindle-shaped/pleomorphic types with poor prognosis. Rarely tumors consist of so-called "chromophobe" cells with finely reticular cytoplasms. They closely resemble clear cell carcinomas and exhibit a similar biological behaviour. According to the grade of atypia in renal carcinomas three grades of malignancy are distinguished. Conclusively, the tumor grade and the tumor cell type are the most reliable indicators of the malignant potential of renal carcinomas.

Carcinoma, Renal Cell↗
PubMed1987

Neuron specific enolase demonstration in the diagnosis of a solid-cystic (papillary cystic) tumour of the pancreas.

Immunoreactivity to neuron specific enolase (NSE) was demonstrated in a solid-cystic (papillary cystic) tumour of the human pancreas, employing immunohistochemical methods. Positive staining for NSE was found with two different antisera. In addition, sodium-dodecyl-sulphate-polyacrylamide-gel-electro-phoresis (SDS-PAGE) of tumour homogenate revealed a distinct band reacting with a NSE antiserum. However, we failed to detect any hormonal products or neuroendocrine granules in the tumour. Therefore the authors advise caution in using the enzyme as a differential diagnostic tool, especially in surgical pathology of epithelial pancreatic neoplasms occurring in young females. In individual cases electron microscopy will be necessary since solid-cystic tumours of the pancreas consistently show large intracytoplasmic zymogen-like granules.

Electrophoresis, Polyacrylamide Gel↗
PubMed1987

Monoclonal islet antibody HISL-19 as a tool in the diagnosis of neuroendocrine carcinomas of the skin.

The monoclonal islet cell antibody HISL-19 generated after immunization of BALB/c mice with human pancreatic islet cell preparations, demonstrated specific immunoreactivity for neuroendocrine (Merkel) cells of the skin as shown by successive and simultaneous localization of neuron-specific enolase and the antigen detected by mab HISL-19 in the same cells of the bovine epidermis. Following these observations, we tested nine neuroendocrine carcinomas of the skin that were believed to be of Merkel cell origin for their immunoreactivity with mab HISL-19 using an indirect immunoperoxidase technique on formalin-fixed and paraplast-embedded tissues. In contrast to malignant lymphomas, poorly differentiated squamous cell carcinomas, and malignant melanomas, all nine neuroendocrine carcinomas reacted strongly with mab HISL-19, indicating its potential as a useful immunohistochemical probe for the distinction of neuroendocrine carcinomas of the skin from other cutaneous neoplasms with similar histological appearance.

Antibodies, Monoclonal↗
PubMed1986

The histopathologic identification of CMV infected cells in biopsies of human renal allografts. An evaluation of 100 transplant biopsies by in situ hybridization.

In order to determine the incidence and significance of CMV infected cells within human renal allograft biopsies 100 transplant biopsies were examined for the presence of CMV DNA within the renal tissue specimens using the in situ hybridization technique. In 41 cases CMV infected cells were predominantly found within proximal tubular epithelial cells, although typical nuclear inclusion ("owl eyes") were absent. In only one case was CMV detected within a few glomerular cells. The presence of CMV infected cells within allograft biopsies does not correlate with active CMV infection of the patients at the time of biopsy. There are no significant differences in the distribution of primary and secondary CMV infections between patients with positive and negative biopsy findings. No significant differences as to the histological alterations between CMV infected and non-infected biopsies could be found. The data give evidence that the renal allograft is more often affected by CMV than is generally appreciated. The in situ hybridization technique may be useful for the fast detection of latently CMV infected cells in renal transplants and thus may influence the choice of therapeutic steps early after transplantation. Furthermore, it may facilitate the diagnosis of interstitial nephritis due to virus infection if typical nuclear inclusions in routinely stained tissue sections are absent.

Biopsy↗
PubMed1986

Monoclonal antibody HISL-19 as an immunocytochemical probe for neuroendocrine differentiation. Its application in diagnostic pathology.

The monoclonal islet cell antibody HISL-19 was generated after immunization of BALB/c mice with human islet cell preparations. Besides reactivity with all cells of the human pancreatic islet, MAb HISL-19 also reacted with other cells of the diffuse neuroendocrine system, including anterior pituitary cells, C cells of the thyroid, endocrine cells of the gut and bronchus, the adrenal medulla, and central and peripheral neurons. In this study the authors screened a series of 53 neuroendocrine and 71 nonneuroendocrine tumors for their reactivity with MAb HISL-19 using an indirect immunoperoxidase technique on formalin-fixed and Paraplast-embedded sections. MAb HISL-19 reacted strongly with all insulomas (10), carcinoids (8), C-cell carcinomas of the thyroid (8), pituitary adenomas (6), neuroendocrine carcinomas of the skin (4), paragangliomas of the carotid body (3), and pheochromocytomas (2) tested. Neuroblastomas (3), oat-cell carcinomas of the lung (2), and melanomas (4) exhibited only very few immunoreactive cells scattered throughout the tumor or remained unstained with MAb HISL-19. With the exception of one lobular carcinoma of the breast (1/3), one adenocarcinoma of the endometrium (1/4), and one adenocarcinoma of the stomach (1/6), nonneuroendocrine tumors were negative with MAb HISL-19. Biochemical findings obtained by SDS-PAGE, "Western" immunoblotting, immunoaffinity chromatography, and absorption experiments indicate that the MAb HISL-19-defined antigen is not related to neuron specific enolase. Because the epitope recognized by MAb HISL-19 is well preserved in formalin-fixed and routinely processed tissues, this monoclonal antibody finds potential applications in diagnostic pathology as an indicator for neuroendocrine cells and their neoplasms.

Antibodies, Monoclonal↗
PubMedDate not supplied

The electrophysiology of cardiac allograft rejection: independent effects of rejection and perioperative ischemia on the sinus node recovery phenomenon after cardiac transplantation.

We characterized the effect of cardiac allograft rejection on the sinus node (SN) recovery response from overdrive suppression. A total of 54 corresponding data sets (SN recovery time [SNRT]/endomyocardial biopsy [EMB]) was available in 24 transplant recipients with normal SNRT. Data were pooled in the rejection vs the no-rejection group (n = 16 vs n = 38, respectively). During cardiac rejection (defined as a 7-day period starting 3 days prior to and lasting until 3 days after the EMB) the SNRT curves were moderately, but significantly shifted towards higher values (F = 13.4, p = .0003). All changes occurred within accepted normal limits for the SNRT. Multivariate analysis indicated independent effects of donor heart ischemic time (p = .0005) on SNRT in addition to that of rejection. After accounting for that influence of ischemic time respective F values regarding the influence of rejection on the SNRT excursions were 10.8 (ischemic time < 100 min, p = .0014) and 4.36 (ischemic time > or = 100 min, p = .039). This study shows that cardiac allograft rejection significantly delays the SN recovery response from overdrive suppression. These changes, however, are subtle and, hence, are an unlikely explanation for the often grossly abnormal postoperative SN function.

Adolescent↗
PubMedDate not supplied

Atrial natriuretic factor production and secretion during clinical total artificial heart-bridge-to-transplantation.

In 5 total artificial heart (TAH)-bridge-to-transplant (BTT) patients production and secretion of atrial natriuretic factor (ANF)1 was studied before, during, and after TAH implantation. Bridging periods lasted between 9 and 28 days. Atrial biopsies were taken during implantation, and after TAH explantation for histologic and histochemical investigations to evaluate differences in morphology and ANF-content of the specific atrial granules. Plasma concentrations of ANF (pANF), aldosterone (PAC) and renin (PRC) were measured daily, as were hemodynamic parameters. In the preoperative state, pANF was always markedly elevated, while during TAH bridging, pANF remained moderately elevated with fluctuations. A positive correlation between pANF levels and right atrial pressure (RAP) was seen in all patients (p less than 0.05). Slight correlation was also observed between pANF and left atrial pressure (LAP), but no correlation was seen between pANF and systemic blood pressure, and no consistent pattern was seen in the plasma concentrations of either renin or aldosterone. After heart transplantation (HTX), which was performed in 3 patients, pANF levels were significantly higher than during TAH, and continued to show a positive correlation with RAP. From our data, we conclude that ANF production sites and secretory mechanisms remain intact during TAH-bridging, although upon implantation of a TAH, the remaining atria are deprived of all coronary blood supply and most autonomic innervation.

Adult↗
PubMedDate not supplied

Inducible atrial flutter and fibrillation after orthotopic heart transplantation.

Inducible atrial flutter (two patients) and fibrillation (two patients) were observed in a series of 35 heart transplant patients who underwent evaluation of sinus node function including premature atrial stimulation. The sinus node function was entirely normal in both patients with inducible atrial flutter. In contrast it was profoundly abnormal in the patients with inducible atrial fibrillation. Atrial fibrillation was no longer inducible as the sinus node function became borderline normal. These observations suggest extensive electrical atrial abnormality, including the sinus node, in patients with atrial fibrillation, and temporary pacing should be available when considering cardioversion in patients with atrial fibrillation early after heart transplantation. Atrial flutter, in contrast, may be inducible in the absence of any sinus node abnormality and without any evidence of rejection.

Adult↗
PubMedDate not supplied

The application of fibrin glue after axillary lymphadenectomy in the surgical treatment of human breast cancer.

Experimental studies point out that a reduction of lymph flow can be obtained by the local application of fibrin glue following axillary lymphadenectomy in the surgical treatment of breast cancer. In a prospective study the influence of human fibrin glue on postoperative axillary lymph secretion and the period of drainage of the wound cavity were evaluated. In 40 patients, 5 ml of fibrin glue (Tissucol) was applied to the wound cavity by the use of a spray applicator (Tissumat) immediately after axillary dissection of the lymph nodes. For drainage of the wound area Redon suction-drains were used. The daily amount of postoperative lymph secretion was measured and drains were removed at a lymph secretion of less than 20 ml. 40 patients who underwent surgery and axillary lymphadenectomy without subsequent application of fibrin glue sourced as control group. No significant difference concerning the total amount of lymph secretion, the mean period of drainage or the incidence of lymphatic cysts was observed. In our study, the expected occlusion of the wound cavity by the application of fibrin glue after axillary lymphadenectomy did not lead to any advantage when compared with the control group.

Adult↗
PubMedDate not supplied

Influence of delayed diagnosis on established prognostic factors in endometrial cancer.

To evaluate the influence of delayed diagnosis on prognostic factors in endometrial cancer, we conducted a retrospective chart analysis based on the data of 116 postmenopausal patients with FIGO stage I-IV endometrial carcinoma. The interval from the first episode of post-menopausal vaginal bleeding to definitive, histological diagnosis (bleeding interval) was compared with tumor stage and various histomorphologic features in endometrial cancer. The mean bleeding interval was 12.7 +/- 17.8 weeks in 74 patients with FIGO stage IA, IB endometrial carcinoma and 35.2 +/- 69.3 weeks in 42 patients with stage IC-IV disease (t-test, p: 0.011). FIGO stage IA, IB disease was diagnosed in 23/26 (88%) patients with a bleeding interval <4 weeks, and in 22/34 (64%) and 29/56 (51%) patients with bleeding intervals of 4-8 weeks and >8 weeks, respectively (Chi-square 10.358, p=0.006). The correlation with histologic grade, lymph-node status, vessel invasion and histologic subtypes did not reach statistical significance. Our data confirm the clinical impression that postmenopausal vaginal bleeding is an early symptom in patients with endometrial cancer, and that advanced disease in the majority of cases might come from delayed diagnosis in women with poor compliance.

Aged↗
PubMedDate not supplied

TATI (tumor associated trypsin inhibitor) and cancer antigen 125 (CA 125) in patients with early-stage endometrial cancer.

BACKGROUND: In patients with gynecologic malignancies, a 6 kD polypeptide known as the tumor-associated trypsin inhibitor (TATI) is present in high concentrations, both in the urine and the serum. This study attempts to evaluate the usefulness of pretreatment serum levels of TATI (cutoff level 21 ng ml-1) and CA 125 (cutoff levels 35 U ml-1 and 65 U ml-1) in the prediction of early endometrial cancer. PATIENTS AND METHODS: One hundred twenty-seven patients with stage I and II endometrial carcinomas, 110 healthy women and 258 women with benign pelvic pathologies were evaluated. The data obtained were correlated with the tumor stage and tumor grade. RESULTS: Overall, TATI showed a sensitivity of 31% and a specificity of 81%. The sensitivity and specificity of CA 125 > 35 U ml-1 was 25% and 86%, respectively. When both serum tumor markers were combined the sensitivity increased to 48% (CA 125 > 35 U ml-1), with a specificity of 71%. A correlation with the depth of myometrial infiltration was found for neither of the tumor markers under investigation. In addition, neither TATI nor CA 125 correlated well with tumor grade. The combination of TATI and CA 125 had a high positive predictive value (84%) when no other gynecologic pathologies were present. Furthermore, if TATI and CA 125 levels are within normal ranges and gynecological examination does not show other abnormalities besides vaginal bleeding, endometrial carcinoma appears to be very unlikely. CONCLUSION: We concluded that, while TATI and CA 125 may not be recommended as a screening method for the detection of endometrial cancer, the combination of TATI and CA 125 is a valuable additional tool for further evaluation of women with suspected uterine cancer.

Adult↗