PubMed Health⌕ Search

Biomedical subjects

J Dyck

Publications and source records attributed to J Dyck.

18 recordsLinked to original sources

Phase I study of MEN-10755, a new anthracycline in patients with solid tumours: a report from the European Organization for Research and Treatment of Cancer, Early Clinical Studies Group.

A phase I study was performed with MEN-10755, a novel anthracycline with promising preclinical antitumour activity, in patients with solid tumours to determine the maximum tolerated dose (MTD); the dose-limiting toxicities (DLTs); to document antitumour activity; and to propose a safe dose for phase II evaluation. MEN-10755 at a starting dose of 15 mg/m2/week was given by short intravenous infusion weekly for 3 weeks and cycles were repeated every 28 days. Twenty-four patients received 55 cycles. Doses of MEN-10755 were 15, 30, 40 and 45 mg/m2. At a dose of MEN-10755 45 mg/m2, treatment could not be given as planned due to neutropenia and one patient developed a decrease in cardiac function. This dose level was considered to be the MTD. Chemotherapy-naive patients could be treated with 40 mg/m2/week, and only one DLT (grade 4 neutropenia) was observed. At that dose, three of six chemotherapy pretreated patients developed a DLT during their first treatment cycle: one patient developed a grade 4 thrombocytopenia, one patient a grade 4 neutropenia and one patient developed a grade 3 acute hypersensitivity reaction resulting in discontinuation of treatment. At this dose level, one other patient did not receive treatment on day 15 as planned due to grade 3 neutropenia. No responses were observed. MEN-107555 at a dose of 30 mg/m2/week in pretreated patients and 40 mg/m2/week in chemotherapy-naive patients for three consecutive weeks followed by 1 week rest is recommended for phase II testing.

Aged↗

Silkiness in brown mink pelts characterized with optical methods.

In mink production, silkiness refers to a silky fur surface. The sensory evaluation of silkiness may be based on information perceived by the eyes and the hands. Silkiness is assumed to depend on hair fiber properties such as guard hair straightness, glossiness, and smoothness. Our objective was to characterize the dorsal surface of brown mink pelts by means of optical variables and relate these to the visual grades of silkiness, thereby forming some objective criteria of silkiness. Two groups of brown male mink pelts (winter coat) that originated from a selection trial with a focus on silkiness were used. The pelts came from a basic (Group 1992) population and a selected (Group 1994) generation. Group 1992 was graded visually on a scale from 1 to 6 (most silky); Group 1994 was graded on a scale from 1 to 8 (most silky). With goniophotometric, nondestructive methods, the reflectance from each pelt surface was measured describing the angle-dependent distribution of reflection in the shape of angular reflectance curves. The measurements were performed along (w-reflectance curve) and across (c-reflectance curve) the guard hairs. The w-curve included a maximum assumed to be related to silkiness. Specular gloss, indicated by the maximum reflectance (s) in the direction of mirror reflection, was positively correlated with silkiness. For Group 1994, s = 72.94 + .49 x silkiness; r2 = .33, P = .0003. Correspondingly, an area representing specular (S) plus diffuse (D) reflectance (S + D) under the curve was positively correlated with silkiness. A decreasing band width of the w-curve at 90% of maximum specular reflectance (w90) was related to an increase of silkiness (Group 1992: r = -.50, P < .01). Furthermore, both s/w90 and (S + D)/w90 were positively correlated with silkiness (Group 1992: r = .49, P < .01 and r = .51, P < .01, respectively). Measures of contrast gloss involving relations or differences between specular and diffuse reflectance were not suitable. From our results, a high degree of specular gloss, indicated by s, explained and was related to an essential part of silkiness and general sensory quality of the pelts investigated. Also, s was relatively easy to measure. Thus, even if the objective variables did not correlate perfectly with visual judgments, s was considered to be the most usable objective variable in characterizing silkiness.

Animals↗

Posttranslational modifications of the 5'-AMP-activated protein kinase beta1 subunit.

The AMP-activated protein kinase (AMPK) consists of catalytic alpha and noncatalytic beta and gamma subunits and is responsible for acting as a metabolic sensor for AMP levels. There are multiple genes for each subunit and the rat liver AMPK alpha1 and alpha2 catalytic subunits are associated with beta1 and gamma1 noncatalytic subunits. We find that the isolated gamma1 subunit is N-terminally acetylated with no other posttranslational modification. The isolated beta1 subunit is N-terminally myristoylated. Transfection of COS cells with AMPK subunit cDNAs containing a nonmyristoylatable beta1 reduces, but does not eliminate, membrane binding of AMPK heterotrimer. The isolated beta1 subunit is partially phosphorylated at three sites, Ser24/25, Ser182, and Ser108. The Ser24/25 and Ser108 sites are substoichiometrically phosphorylated and can be autophosphorylated in vitro. The Ser-Pro site in the sequence LSSS182PPGP is stoichiometrically phosphorylated, and no additional phosphate is incorporated into this site with autophosphorylation. Based on labeling studies in transfected cells, we conclude that alpha1 Thr172 is a major, although not exclusive, site of both basal and stimulated alpha1 phosphorylation by an upstream AMPK kinase.

AMP-Activated Protein Kinases↗

Idiopathic dilation of the right atrium: case report and survey of the literature.

Idiopathic dilation of the right atrium (IDRA) is a rare cardiac anomaly of unknown etiology. Whether it is an acquired or congenital lesion is controversial. A case of IDRA detected in utero and confirmed postnatally is reported. The postnatal course was complicated by the development of atrial flutter successfully treated with sotalol. A review of the literature concerning IDRA is presented.

Adult↗

A novel method to create atrial septal defect using a cutting balloon in piglets.

A new method of creating atrial septal defect, using a 3- or 4-blade cutting balloon catheter combined with conventional static balloon dilation, is discussed. Radially directed surgical cuts made in the atrial septum were enlarged by balloon angioplasty, producing defects measuring 3 to 8 mm, with a mean Qp/Qs of 1.96/L.

Angioplasty, Balloon↗

Cardiac dysfunction late after cardiotoxic therapy for childhood cancer.

Despite a wealth of data documenting acute cardiac injury from anthracycline therapy and/or mediastinal radiotherapy used for childhood cancer, little information is available on the long-term consequence of these insults. Twenty-nine patients (mean age 15 +/- 4.3 years) from The Late Effects Follow-Up Clinic For Childhood Cancer study, who had been in continuous, complete remission and off chemotherapy for a minimum of 2 years (mean follow-up 7.2 +/- 3.2) were studied. All patients had normal ejection fractions before and during cancer therapy and all were in New York Heart Association class I at the time of study. Systolic and diastolic functions were assessed by 2-dimensional echocardiography, Doppler flow velocity, and radionuclide angiography, and results were compared with normal control subjects. Left ventricular mass and mass index were significantly reduced in the patient population. Fractional shortening was decreased overall and end-systolic wall stress was much higher in patients than in controls. However, contractility, as assessed by the relation of wall stress to rate-corrected velocity of shortening, was decreased by > or = 2 SDs in only 6 of 28 patients, and the force-mass relation was actually increased in the patient group as a whole. Mitral valve inflow velocities were significantly increased but the pattern was abnormal. These results suggest a pattern consistent with a thin-walled, complaint left ventricle with reduced muscle mass performing under above-normal levels of wall stress. Contractility measurements were normal or increased in the group, but some patients clearly demonstrated development of reduced contractile function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Balloon atrial septostomy under transesophageal echocardiographic guidance.

Balloon atrial septostomy is an established method of palliation for several forms of congenital heart disease. Previously performed under fluoroscopic x-ray control, recent reports have demonstrated the utility of transthoracic echocardiographic monitoring. We report the first application of uniplane transesophageal echocardiography (TEE) (6.7-mm probe) as an alternative imaging modality for control of balloon atrial septostomy on neonates in the intensive care unit.

Catheterization↗

Results of the Fontan procedure for patients with univentricular heart.

One hundred twenty-four consecutive patients with univentricular heart undergoing the Fontan operation were reviewed. Patients with tricuspid atresia or biventricular heart with hypoplasia of one ventricle were excluded. Eighty-four patients had left ventricular morphology. Atrioventricular connection was double-inlet (n = 76), common (n = 29), absent left atrioventricular connection (n = 14), and absent right atrioventricular connection (n = 5). Actuarial survival was 77% (70% confidence limits, 73% to 81%) at 1 year, 66% (70% confidence limits, 60% to 72%) at 5 years, and 49% (70% confidence limits, 36% to 61%) at 10 years, indicating a continuing risk for premature death. Multivariate analysis identified preoperative ventricular function and hypertrophy as risk factors for survival. High postrepair right atrial pressure (greater than 15 mm Hg) emerged as a strong intraoperative predictor of survival. Logistic regression analysis of these factors predicts high probability of death for certain subgroups of patients after the Fontan operation. Forty-four percent (n = 53) of these original 124 patients are alive and in New York Heart Association class I at follow-up. Thirty-eight percent (n = 33) of survivors have worse ventricular function than preoperative. Long-term survival is disappointing. Certain identifiable subgroups of patients with univentricular heart have unacceptable risks for the Fontan operation and should have alternate management. High postrepair right atrial pressure is an ominous sign, and if it persists the Fontan should be fenestrated or taken down.

Adolescent↗

Production of mesenchymal tumors in nude mice by Ph1 negative fibroblasts obtained from a Ph 1 positive CML patient: a preliminary report.

An experimental model system is presented for the investigation in humans of the role of hematopoietic stromal elements in the regulation of hematopoiesis as well as in the pathogenesis of myelofibrosis in myeloproliferative disorders. The model is based on the simultaneous application of three experimental techniques: (1) growth of bone-marrow derived fibroblastic colonies in vitro, (2) cytogenetic demonstration of marker chromosomes associated with hematopoietic malignancies, and (3) the transplantation of isolated stromal elements into athymic (nude) mice. Using this model, we describe the induction of mesenchymal tumors in nude mice by Ph1 negative fibroblasts obtained from the bone marrow of a patient with a Ph1 positive chronic myelogenous leukemia. Mesenchymal tumors also were induced in nude mice with bone marrow-derived fibroblasts from a patient with aplastic anemia, who was successfully treated with bone marrow transplantation, and from a normal human volunteer. Morphologic, cytogenetic and electron microscopic studies of bone marrow mesenchymal elements in culture and of tumors induced in nude mice from the CML patient indicate the cells composing the tumor are of human origin and are negative for the Ph1 chromosome. The results provide the first in vivo morphological and cytogenetic support using human materials, of the hypothesized relationship of progenitors of in vitro fibroblastic colonies to marrow stromal elements.

Animals↗

Growth of canine T-lymphocyte colonies in vitro.

Canine lymphocytes from peripheral blood, lymph nodes, thymus and bone marrow were stimulated with phytohemagglutinin-P (PHA) or concanavalin-A (CON-A) to form colonies in methylcellulose. Lymphocytes exposed to mitogens in liquid phase formed clumps the size of colonies. Lymphocyte clumping was eliminated by plating cells directly into methylcellulose, but high concentrations of mitogens (CON-A or PHA is greater than 10 mg/10(6) lymphocytes) were required in order to get subsequent colony formation. Thus, in contrast to published reports, exposure of lymphocytes to mitogen prior to plating was not required for cloning of canine peripheral blood lymphocytes. Colonies from thymus, lymph node, or peripheral blood consisted predominantly of T lymphocytes, whereas cultures from bone marrow also produced colonies with macrophage morphology and surface-adherent colonies with mesenchymal morphology.

Animals↗