Biomedical subjects

J Sinai

Publications and source records attributed to J Sinai.

11 recordsLinked to original sources

PubMed2001

Developing a training program to improve supervisor-resident relationships, step 1: defining the types of issues.

BACKGROUND: By some estimates, the teacher-learner relationship explains roughly half of the variance attributed to the effectiveness of teaching. Despite this, relationships largely have been ignored in the educational literature. PURPOSE: This qualitative pilot study sought to identify factors in the supervisor-resident relationship that hinder learning among University of Toronto psychiatry residents. METHOD: Thirteen postgraduate-year residents in Years 2-5 and their supervisors were interviewed regarding interactions that either assisted or adversely affected learning. RESULTS: Qualitative analysis of the interview data led to the identification of 5 types of issues affecting the supervisory relationship: goals and individual differences, communication and feedback, power and rivalry, support and collegiality, and role modeling and expertise. Face validity was supported when typed anonymous written feedback obtained from annual supervisor evaluations also could be organized into the 5 categories. CONCLUSIONS: Recognition of the types of interpersonal interactions that assist or hinder learning may contribute to enhanced teaching effectiveness.

Canada↗

PubMed2000

Macrophage-recognized molecules of apoptotic cells are expressed at higher levels in AKR lymphoma of aged as compared to young mice.

While a direct relation between aging and tumorigenesis is well established, a slower tumor progression rate was reported in old as compared to young cancer patients. The mechanisms responsible for the less aggressive behavior of tumors in the aged, are largely unknown. We have recently shown an increase in apoptotic cell death in tumors derived from aged as compared to young animals in the AKR lymphoma. This was shown by DNA flow cytometry and by the ladder type DNA fragmentation in agarose gel electrophoresis. Analysis of the expression of genes involved in apoptosis in tumors derived from young and old animals showed a lower bcl-2 expression in those from the aged. The Fas antigen, on the contrary, displayed higher expression levels on lymphoma cells derived from old than on those from young mice. Apoptotic cells are recognized and phagocytosed mainly by macrophages. One molecular property of apoptotic cells which is recognized by macrophages is a loss in cell surface sialic acid concomitantly uncovering galactose residues. While comparing the "eat me status" phenotype of the tumor cells derived from young and aged animals, by the use of lectins recognizing sialic acid and galactose residues, FACS analysis showed a decrease in cell surface sialic acid and a gain in galactose residues in aged as compared to young mice. Moreover, Western blot analysis showed that a 130 Kda sialylated membrane glycoprotein was expressed at a lower level in tumors from the old as compared to young mice. Our results, at both the cellular and molecular levels, particularly with regard to molecules recognized by macrophages, indicate that increased apoptotic cell death in tumors from old as compared to those from young animals constitutes, as we have previously suggested, one of the mechanisms of the age-related decrease in tumor progression rate.

Aging↗

PubMed2000

Apoptosis and cell proliferation capacity in AKR lymphoma malignancy variants.

Dysregulation in apoptotic cell death has recently emerged as a factor in tumorigenesis, but its effect in tumor progression is not yet established. In the present study we evaluated the levels of proliferative and apoptotic cell fractions in a T-cell lymphoma tumor progression model. We compared these features and the expression of apoptosis-related genes in primary tumors of several AKR lymphoma malignancy variants. According to DNA flow cytometry, a considerable proportion of cells (35-40%) was in the proliferative (S + G2/M) phase in all variants, but a slight augmentation with increasing malignancy was noted. Apoptotic cell content was, unexpectedly, the lowest in the less malignant variant. This might be due to the higher content in macrophages observed in this variant, which possibly partly eliminated apoptotic bodies. We found an increase in bcl-2 level with increasing malignancy that was probably counterbalanced by the simultaneous increase observed in the Fas receptor.

Animals↗

PubMed1997

The use of metaphor by an artless first-time psychotherapist.

The experience in a psychiatric residency of being a psychotherapist for the first time can be overwhelming and anxiety-provoking. This paper examines a first psychotherapy case which utilizes a theory-distant approach based on the use of metaphor. Metaphorical theory is reviewed, and potential benefits and pitfalls of using metaphor are examined. An in-depth case study is done, focusing on the following six metaphors: Art as Psychotherapy; Psychotherapy as Art; The World Is a Trap; Mothers Are Martyrs; StepMothers Are Evil; and Artists Are Crazy. Each metaphor was utilized in multiple layers through the course of the therapy. Some of the current research in the use of metaphor in psychotherapy is reviewed. Through this approach, I was able to develop necessary psychotherapeutic skills without being overwhelmed by traditional theories such as Freudian, Object Relations or Self Psychology. I conclude that the use of metaphor with my first psychotherapy patient strengthened the therapeutic alliance, allowed an idiosyncratic language to develop in the therapy, structured recurrent themes, and permitted me to respect the patient's defenses.

Adolescent↗

PubMed1997

Comparison of growth rate of two B16 melanomas differing in metastatic potential in young versus middle-aged mice.

The rise of cancer frequency as a function of age is a well-established fact. The aspect of the host age-tumor progression relationship, namely the slower metastatic spread in aged patients, has been investigated to a lesser extent. In the present study, we examined whether host-age-dependent growth rate varies with metastatic capacity of the tumor. The parental B16 and the B16/Col/R, a highly metastatic variant, were employed. A more pronounced growth of both tumors in young as compared to middle-aged mice was found. However, the differential growth in middle-aged versus young mice was more evident in the highly metastatic variant. According to the tumor size data, a sixfold growth reduction in middle-aged mice was observed with B16/Col/R and an only twofold growth reduction was seen with the B16 melanoma. The data might eventually contribute to the finding of more appropriate treatment modalities for the middle-aged cancer patient.

Aging↗

PubMed1995

Role of immune response as determinant of tumor progression in function of host age in the B16 melanoma.

Aging constitutes the major cause for the development of most neoplastic diseases. However, tumors in aged people present with a lower degree of aggressiveness than in young patients. The reasons for this paradoxical behavior are not clear. We attempted to verify whether the immune system has a role in the relation between host age, immune response and tumor progression. We compared the growth rate of B16 melanoma and a highly malignant variant, the B16/Col/R, in young and aged mice that have or have not undergone splenectomy. The following results were obtained: (1) Splenectomy stimulated growth in the parental melanoma in both young and aged mice, indicating a protective role of the spleen against this tumor at all ages; (2) Spleen ablation provoked inhibition of the highly-metastatic variant growth in young mice, suggesting a stimulatory role of the spleen in this case; (3) By contrast, in aged mice inoculated with the B16/Col/R variant, splenectomy enhanced tumor growth, indicating a defensive role of the spleen. Age favors a positive host response against the aggressive clone of the melanoma. Differential host response in young versus aged mice can explain, in this tumor system, the difference in tumor progression rate as a function of age.

Age Factors↗

PubMed1995

Comparison of splenectomy effects as an indication for host response to growth of primary and metastatic tumour cells in two murine tumour systems.

The tumour-host relation is of extreme complexity; moreover, it may change during tumour progression. Information regarding this relation may be of importance in appreciating the efficiency of immunotherapy. In the present study, the effect of splenectomy on tumour growth in two murine tumour progression models, the Lewis lung carcinoma and AKR lymphoma, was examined. The effect of spleen ablation on growth of cells derived from primary and metastatic tumour cells was tested. The data obtained showed a differential effect of splenectomy on the growth of primary versus metastatic tumour cells in the two tumour systems, indicating a differential host response induced by the two cell types and/or a differential tumour cell sensitivity to immune reactions. Surprisingly, the spleen appeared to have a defensive role against metastatic tumour cells and a growth enhancing influence on primary tumour cells. The instability of the tumour-host relation may have important implications for the chances of immunotherapy to serve as an efficient cancer treatment.

Animals↗

PubMed1988

Ultrasonic scattering by two concentric cylinders.

A series solution for scattering from two concentric, fluid cylinders of different speeds and densities has been employed to compute the scattered pressure for a range of frequencies, material parameters, and emitter and detector functions. This range includes the nominal parameters of measurements that were made at a frequency of 1.0 MHz and a radius of 150 mm on a gel model with an outer radius of 25.00 mm and an inner radius of 9.52 mm. The nominal parameters correspond to a ka of 626.2 for the measurement radius, a ka of 106.0 for the outer cylinder, and a ka of 39.8 for the inner cylinder. Scattering was calculated for frequencies for 10 kHz to 10 MHz which resulted in ka values from 6.26 to 6262 for the measurement radius, from 1.06 to 1060 for the outer cylinder, and from 0.398 to 398 for the inner cylinder. The effects on scattering of changes in speed and density parameters of the concentric cylinders are presented. First, the speed of the outer cylinder was raised by a factor of 10 from the nominal while the density of the outer cylinder and the speeds and densities of the inner cylinder and the surrounding medium were held fixed. Next, the density of the outer cylinder was raised while its speed was fixed at nominal, as were the speeds and densities of the inner cylinder and the medium. Finally, the speed first and then the density of the inner cylinder was raised while the parameters of the outer cylinder and of the medium were held fixed at nominal.(ABSTRACT TRUNCATED AT 250 WORDS)

Gels↗

PubMed1987

Insulin deficiency and insulin resistance in type 2 (non-insulin-dependent) diabetes: quantitative contributions of pancreatic and peripheral responses to glucose homeostasis.

A non-steady state dose-response study was designed to quantitate peripheral sensitivity to insulin and pancreatic responsiveness to glucose, and to assess their relative contribution to glucose intolerance in Type 2 diabetes (Type 2 DM, non-insulin-dependent). Eleven lean and eleven obese patients with mild diabetes (fasting plasma glucose, FPG, 10.3 +/- 1.0 and 9.4 +/- 0.6 mmol l-1, respectively) were examined; twenty-six lean and twelve weight-matched obese subjects served as controls. Pancreatic response was measured by sequential injection of 0.1, 0.3 and 0.9 g kg-1 glucose; peripheral sensitivity to insulin was determined from the rate of clearance (Kgluc) of 0.3 g glucose injected sequentially together with 25, 50 and 100 mU insulin kg-1 or with 0, 12.5 and 50 mU kg-1, under somatostatin infusion. The mean dose-response curve describing glucose-induced insulin release showed increased maximal capacity to secrete insulin in obese controls, while the responses of lean as well as obese Type 2 DM were reduced by more than 80%. The mean dose-response curves relating plasma exogenous insulin levels to Kgluc were similar in lean diabetics and lean controls. The curves of both obese controls and obese diabetics were shifted to the right, demonstrating similar insulin resistance. In four lean controls, sensitivity to insulin was tested also during a hyperglycemic clamp set at 10.3 +/- 0.6 mmol l-1. Hyperglycemia reduced the Kgluc at all insulin levels. Individual dose-response curves were transformed to single weighted numerical pancreatic responsiveness scores [PRS], and peripheral sensitivity scores [PSS].(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1987

Production of carcinoembryonic antigen from a human colon adenocarcinoma cell line. I. Large-scale cultivation of carcinoembryonic antigen-producing cells on cylindric cellulose-based microcarriers.

A continuous cell line from a human colon carcinoma, designated HuCC1-14, was successfully grown on cyclindrical cellulose microcarriers (MC) charged by DEAE. The cells grow on these carriers as large cell-MC aggregates and maintain high cell densities in submerged conditions for extended periods. HuCC1-14 cells secrete into the culture medium significant amounts of carcinoembryonic antigen (CEA). Maximum efficiency in CEA secretion occurred after the cells switched from logarithmic growth to stationary phase. At this state, high CEA levels could be obtained with low-serum medium which greatly facilitates subsequent product purification. The described method provides a system which can be scaled-up and produce this tumor-associated antigen in essentially unlimited amounts and reproducible quality for detection and monitoring of cancer patients.

Adenocarcinoma↗

PubMed1985

Relative potencies of human and pork insulin during i.v. and oral glucose tolerance test in lean and obese persons.

The biological efficacy of biosynthetic human insulin (BHI) of recombinant DNA origin was compared with that of highly purified pork insulin in subjects with normal (lean persons) and decreased (obese persons) sensitivity to insulin. Sequential i.v. administration of glucose with increasing insulin doses under somatostatin coverage was used to establish the dose-response characteristics of insulin-induced glucose clearance [insulin vs. Kg (glucose disappearance rate, %/min). Insulin was also given s.c. prior to an oral glucose tolerance test (OGTT) performed under somatostatin blockade; the appearance of insulin in serum and the modification of glucose levels were followed. The insulin vs. Kg dose-response curve was flatter and shifted to the right in obese persons compared with lean persons, demonstrating insulin resistance. In both lean and obese subjects, BHI and pork insulin had comparable effects on glucose clearance. Similarly, the effect of s.c. insulin on the serum glucose values during OGTT was the same when BHI or pork insulin were used. The absorption characteristics from the injection site were similar for both insulins. Thus, in man, human and pork insulin have similar pharmacokinetic and biological characteristics.

Administration, Oral↗