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Biomedical subjects

I Cohen

Publications and source records attributed to I Cohen.

At least 91 records · Page 5Linked to original sources
PubMed1999

Positivity in a modified mixed leukocyte reaction test correlates with molecular HLA-C disparity in prediction of unrelated bone marrow transplantation outcome.

The modified mixed leukocyte reaction (MMLR) test consists of the standard MLR (SMLR) test to which interleukin-4 (IL-4) has been added. It is a sensitive procedure capable of detecting alloreactivity not detected by the SMLR. In the present study we applied the MMLR test to unrelated bone marrow transplantation (BMT) in an attempt to predict graft versus host disease (GVHD) and graft rejection (GR) by detecting alloreactivity between recipient/donor pairs otherwise found to be fully matched (HLA class I A and B tested by serology; class II DRB1 and DQB1 by sequence specific oligonucleotide probes [SSOP]) and by studying the relationship of MMLR alloreactivity and HLA-C disparity in the prediction of transplant related complications. Thirty-five patients transplanted from unrelated donors were included in the study. The MMLR test was seen to correlate with the incidence of transplant related complications, as of the 19 positive, cases 12 (63%) developed acute GVHD and 7 (37%) GR, while of the 16 negative cases only 5 (31%) developed GVHD (4 acute, 1 chronic) (p = 0.0001) and 2 (12.5%) GR. No such correlation was seen between the SMLR and the incidence of transplant related complications: the SMLR test was positive in only 4 (11%) cases (all of which developed GVHD or GR) but of the 31 negative cases 22 (71%) also developed GVHD or GR. Reactivity in the MMLR also correlated with molecular HLA-C disparity (p = 0.015): While of the 19 positive cases 10 (53%) had molecular HLA-C disparity, of the 16 cases with negative MMLR, 14 (87.5%) were matched for molecular HLA-C. Two-way analysis confirmed that patients with positive MMLR transplanted from HLA-C mismatched donors were more likely to develop post BMT complications, including GVHD and GR, than patients with negative MMLR transplanted from HLA-C matched donors (r = +0.70) (p = 0.001). We conclude that the MMLR test may be a useful tool in the prediction of transplant related complications such as GVHD and GR, post unrelated BMT. Moreover, the MMLR test, in conjunction with molecular HLA-C typing, may improve unrelated donor selection.

Adolescent↗
PubMed1999

Dose-dependent effect of tamoxifen therapy on endometrial pathologies in postmenopausal breast cancer patients.

To assess whether a higher cumulative tamoxifen dose is associated with increased incidence of various types of endometrial pathologies, we compared cumulative dose of tamoxifen treatment as well as demographic characteristics, risk factors for endometrial cancer, transvaginal ultrasonographic endometrial thickness, and various treatments for the primary breast cancer between 159 postmenopausal breast cancer tamoxifen-treated patients without endometrial pathologies (group I) and 67 similar patients with endometrial pathologies (group II). A similar comparison was made between group I patients and similar patients with proliferative endometrium (group IIa), with endometrial hyperplasia (group IIb), with endometrial polyps (group IIc), and with endometrial cancer (group IId). Overall cumulative tamoxifen dose was significantly higher in group II as compared to group I (27.4+/-33.4 and 17.4+/-20.2, respectively; P<0.0252). Transvaginal ultrasonographic endometrial thickness was significantly higher in group II than in group I patients (16.3+/-11.3 mm and 12.1+/-6.3 mm, respectively; P<0.0147). The frequency of diabetes mellitus, of previous postmenopausal bleeding, and of previous exposure to hormone replacement therapy was significantly higher in group II than in group I patients (P<0.001, P<0.0001 and P<0.001, respectively). There were no significant differences in all parameters tested between group I, group IIa, group IIb, group IIc, and group IId. However, there was an obvious trend for higher cumulative tamoxifen dose in patients with benign endometrial pathologies as compared to those without endometrial pathologies or to those with endometrial cancer (Group I = 17.4+/-20.2 g, group IIa = 22.5+/-18.5 g, group IIb = 28.1+/-20.3 g, group IIc = 31.4+/-42.7 g and group IId = 10.4+/-12.6 g). Endometrial pathologies, except for endometrial cancer, are associated with a high cumulative dose of tamoxifen in postmenopausal breast cancer patients.

Aged↗
PubMed1999

Successful co-treatment with LHRH-agonist for ovarian over-stimulation and cystic formation in premenopausal tamoxifen exposure.

The present study evaluates the potential beneficial effect of co-treatment with LHRH-agonist in resolving premenopausal tamoxifen's induced supraphysiological serum 17beta estradiol levels and persistent ovarian cysts. Ultrasonographic and serum hormonal evaluations were performed before, during, and following three consecutive injections of long acting LHRH-agonist administered to 14 premenopausal breast cancer patients treated with tamoxifen, who had supraphysiological serum 17beta estradiol levels and simultaneous persistent ovarian cysts. Within 3 weeks of the first LHRH-agonist injection, all patients had menopausal serum estradiol levels. Ovarian cysts completely disappeared within 2 months following the first injection. Following the discontinuation of LHRH-agonist co-treatment, serum estradiol levels remained in physiological levels and the ovaries remained a normal size in 64.3% of the patients for 13.3 +/- 11.5 months. 28.6% of the patients had a gradual reappearance of high serum estradiol levels and of ovarian cysts, and were, therefore, treated with a second course of LHRH-agonist. Following the second course, serum estradiol levels remained in physiological levels and the ovaries remained a normal size for 8-15 months. It is concluded that short duration of co-treatment with long acting LHRH-agonist administered to premenopausal breast cancer patients treated with tamoxifen, successfully resolved the tamoxifen-induced supraphysiological serum 17beta estradiol levels and the ovarian cysts.

Adult↗
PubMed1999

Resistance to blood flow in ovarian tumors: correlation between resistance index and histological pattern of vascularization.

OBJECTIVE: To investigate the correlation between the histological patterns of vascularization and the resistance index (RI) in ovarian tumors. DESIGN: In a retrospective study, the histological sections of the ovarian tumors with known preoperative RI values were reviewed and the pattern of vascularization was studied. SUBJECTS: Twenty-two women underwent B-mode sonography and color Doppler ultrasound within 3 days prior to explorative laparotomy for ovarian masses in the years 1992-93. METHODS: The RI of the ovarian tumors was calculated as the mean of three consecutive waveforms with the lowest RI. The representative histological sections were evaluated for quantity of arterioles and venules, after staining by Masson trichrome and Elastic Van Gieson. The arteriolar fraction (defined as the number of arterioles divided by the sum of the arterioles plus venules) and the density of vessels (defined as the number of arterioles and venules per microscopic field) were calculated in each histological section and correlated with the preoperative RI values. RESULTS: The mean RI was 0.36 +/- 0.07 for malignant tumors and 0.57 +/- 0.03 for benign tumors. Ovaries with malignancies showed significantly lower arteriolar fraction values (0.30 +/- 0.12) than those with benign tumors (0.56 +/- 0.05) and those with metastatic tumors (0.43 +/- 0.2) (p < 0.002 and p < 0.001, respectively). The density of vessels was higher in malignant tumors (8.0 +/- 3.8) than in benign lesions (2.7 +/- 1.5) (p < 0.01). RI values showed a strong positive correlation (r = +0.85, p < 0.0005) with the arteriolar fraction and a negative and weaker correlation (r = -0.69, p < 0.001) with the density of vessels. CONCLUSIONS: RI values are predominantly determined by the proportion of arterioles. The correlation between the histological pattern of vascularization and RI values reflects tumor angiogenesis and increases understanding of the advantages and limitations of measuring vascular resistance by color Doppler ultrasound.

Female↗
PubMed1999

Prenatal diagnosis of dacryocystocele: a possible marker for syndromes.

We present our experience of the sonographic prenatal diagnosis of dacryocystocele and review the literature. This lesion can be distinguished from a facial hemangioma, dermoid or anterior encephalocele by the ultrasound findings and Doppler flow studies. These conditions are separate entities and their associated diagnosis and prognosis are very different in each case. As dacryocystocele may be part of numerous syndromes, its prenatal visualization raises the rare possibility of associated anomalies.

Adult↗
PubMed1999

Megakaryocyte ex vivo expansion potential of three hematopoietic sources in serum and serum-free medium.

Megakaryocytes (MK) were expanded from purified human CD34+ cells obtained from three sources, bone marrow (BM), mobilized peripheral blood progenitor cells (PB), and umbilical cord (UC) blood. CD34+-selected cells were cultured for 12 days with 10 ng/ml thrombopoietin (TPO), 10 ng/ml IL-3, 10 ng/ml TPO + 10 ng/ml IL-3, or 200 ng/ml promegapoietin (PMP), a chimeric dual agonist of the c-Mpl and human IL-3 receptors. MK production was compared in serum-free versus human serum-supplemented liquid media. PMP and the combination of TPO and IL-3 (TPO + IL-3) increased MK production similarly. Culturing CD34+ cells with PMP in serum-free medium resulted in a twofold increase in MK yield compared with serum-supplemented medium. CD34+ cells from UC proliferated more than those from either BM or PB in liquid culture, resulting in much greater MK production under all conditions. Phenotypic analysis of the uncultured CD34+ cells showed that BM had a higher frequency of CD34+/CD41+ cells than PB or UC. TPO + IL-3 or PMP produced larger and greater numbers of BFU-MK and CFU-MK per seeded CD34+/CD41+ cell from UC than from either BM or PB. Thus, although uncultured CD34+-selected BM cells contained a higher frequency of committed mature MK progenitors, UC CD34+ cells had a greater proliferative capacity and, therefore, were more productive. PMP induced megakaryocytopoietic activity comparable to that achieved with TPO + IL-3 and may be useful for ex vivo expansion of MK for clinical trials.

Bone Marrow↗
PubMed1999

Endometrial cancers in postmenopausal breast cancer patients with tamoxifen treatment.

To evaluate possible predicting factors for endometrial cancer in postmenopausal breast cancer patients with tamoxifen treatment, we compared various clinical features between 12 postmenopausal breast cancer tamoxifen-treated patients with endometrial cancer and a control group of 261 otherwise similar patients without this endometrial pathology. These comparisons were based on a long-term prospective follow-up. Several clinical factors such as longer duration of breast disease, older patient age, lower frequency of chemotherapy administration, and higher frequency of postmenopausal bleeding were found among the tamoxifen-treated patients with endometrial cancers, and were significantly different when compared to the control group. Only eight (66.7%) had postmenopausal bleeding, and a preoperative diagnosis of endometrial cancer was made in only six (50.0%). When considering postmenopausal bleeding as a marker for endometrial cancer in the study patients, sensitivity was 67% and specificity was 98%.

Adenosarcoma↗
PubMed1999

Lubricating bacteria model for branching growth of bacterial colonies.

Various bacterial strains (e.g., strains belonging to the genera Bacillus, Paenibacillus, Serratia, and Salmonella) exhibit colonial branching patterns during growth on poor semisolid substrates. These patterns reflect the bacterial cooperative self-organization. A central part of the cooperation is the collective formation of a lubricant on top of the agar which enables the bacteria to swim. Hence it provides the colony means to advance towards the food. One method of modeling the colonial development is via coupled reaction-diffusion equations which describe the time evolution of the bacterial density and the concentrations of the relevant chemical fields. This idea has been pursued by a number of groups. Here we present an additional model which specifically includes an evolution equation for the lubricant excreted by the bacteria. We show that when the diffusion of the fluid is governed by a nonlinear diffusion coefficient, branching patterns evolve. We study the effect of the rates of emission and decomposition of the lubricant fluid on the observed patterns. The results are compared with experimental observations. We also include fields of chemotactic agents and food chemotaxis and conclude that these features are needed in order to explain the observations.

Bacteria↗
PubMed1999

Endometrial pathology in postmenopausal tamoxifen treatment: comparison between gynaecologically symptomatic and asymptomatic breast cancer patients.

AIMS: To evaluate whether endometrial pathology is more likely to be diagnosed in gynaecologically symptomatic rather than in gynaecologically asymptomatic postmenopausal breast cancer patients with tamoxifen treatment; and to evaluate the possible influence of various clinical factors on the incidence of endometrial pathology. METHODS: Endometrial histological findings, transvaginal ultrasonographic endometrial thickness, demographic characteristics, health habits, and risk factors for endometrial cancer were compared between 14 gynaecologically symptomatic (group I) and 224 gynaecologically asymptomatic (group II) postmenopausal breast cancer patients with tamoxifen treatment. RESULTS: Overall, 28.6% of the study population had endometrial pathology. The incidence of overall positive endometrial histological findings was significantly higher in group I than in group II (92.9% v 24.6%, p < 0.0001). Atrophic endometrium was more common in group II than in group I (75.3% v 7.1%, p < 0.0001). Most other endometrial pathology was significantly more common in group I than in group II (endometrial hyperplasia, 35.7% v 5.6%, p < 0.0001; endometrial polyps, 35.7% v 13.4%, p < 0.0111; endometrial carcinoma, 21.5% v 0.9%, p < 0.0001). Endometrial pathology appeared considerably later in the gynaecologically asymptomatic patients than in gynaecologically symptomatic patients (p = 0.0002). Vaginal bleeding or spotting occurred exclusively in group I. The incidence of endometrial pathology in the entire study population was consistent with that reported elsewhere, and higher than that reported for healthy postmenopausal women. CONCLUSIONS: Endometrial pathology is more likely to be diagnosed in gynaecologically symptomatic postmenopausal breast cancer patients with tamoxifen treatment, and after a shorter duration of time, than in gynaecologically asymptomatic patients.

Antineoplastic Agents, Hormonal↗
PubMed1999

Postmenopausal endometrial pathologies with tamoxifen treatment: comparison between hysteroscopic and hysterectomy findings.

Histological findings of endometrial specimens collected by hysteroscopy from 261 postmenopausal breast cancer patients with tamoxifen treatment (group I) and from endometrial specimens obtained following hysterectomy from 40 similar patients (group II) were compared. This comparison was performed in order to assess whether endometrial pathologies are more frequently diagnosed in specimens collected by hysterectomy than by those collected during hysteroscopy in such patients. Overall positive endometrial histological findings were significantly more common in group II patients than in group I patients (82.5 and 24.5%, respectively; p < 0.0001). Atrophic endometrium was significantly more common in group I patients than in group II patients (75.5 and 15.0%, respectively; p < 0.0001). All other different endometrial pathologies, except for proliferative endometrium, were significantly more common in group II patients than in group I patients (endometrial hyperplasia = 17.5 and 4.2%, respectively; p < 0.0003; endometrial polyps = 30.0 and 11. 5%, respectively; p < 0.006; endometrial polyps with hyperplasia = 17.5 and 4.2%, respectively; p < 0.0003; endometrial carcinoma = 15. 0 and 0.4%, respectively; p < 0.0001). These findings suggest that in postmenopausal breast cancer patients treated with tamoxifen, the frequency of various endometrial histological findings and of overall positive endometrial histological findings were significantly higher in specimens collected by hysterectomy than in specimens obtained by hysteroscopy.

Aged↗
PubMed1999

Abortion service in Amsterdam: deciding and coping in a liberal system.

OBJECTIVES: The Netherlands have liberal abortion laws and contraceptives are easily available. In the AMC, a service protocol is designed to facilitate decision-making. In this context, the following questions arise: Do our abortion clients know what went wrong with their contraceptive behavior? Did they decide for more effective contraception afterwards? How did they feel about their own decision and about our services, which include obligatory counselling? STUDY DESIGN: A questionnaire was sent to 23 consecutive clients, who were willing to cooperate. The questionnaire consisted of a scale with 26 items and two open-ended essay-questions. RESULTS: The response rate was 45% (11 complete questionnaires). Seven women had used contraceptives, six knew what had gone wrong, five had decided to improve their contraception, four women had not used contraceptives, out of which two decided to start, seven women found the abortion decision difficult, seven women (not the same) were content with their decision, and one of them felt bereaved. The four who were not, on the whole, content with their decision felt bereaved. Eight appreciated our services, ten had used the essay-questions to tell their own story. One woman explicitly regretted her decision and would have liked more intensive counselling. CONCLUSIONS: Our system does not yet function as it should. The reasons may be psychological (unexplored ambivalence), sociocultural (difficulties in using effective contraception) and cognitive (some women were very young and not adequately informed). On a methodological level, we conclude that open-ended questions on these subjects generate more accurate and subtle information.

Abortion, Legal↗
PubMed1999

The effect of single hind-limb immobilization on the contralateral limb in the rat: a morphometric and biochemical study.

Disuse atrophy has been the subject of research studies that make the use of an animal model in which single-limb immobilization induces atrophic changes in the immobilized limb. The effect upon the nonimmobilized contralateral limb is, however, still unclear, and findings in the literature are inconclusive. We therefore performed a multidisciplinary study to clear this issue. The experimental population was 70 young male Sprague-Dawley rats. In one group of 35 rats, the left hind limb was immobilized for 3 weeks. Another group of 35 rats served as controls. limb and tibial bone weights (both "dry" and "ash") were found to be reduced in both hind limbs. Bone alkaline phosphatase (ALP) activity was likewise reduced in both limbs. We conclude that the contralateral hind limb in the rat is clearly subjected to atrophic changes that are similar in magnitude or severity to those experienced by the immobilized limb. We further discuss these findings in view of previous knowledge regarding the atrophic process.

Alkaline Phosphatase↗
PubMed1999

Microscopic alterations in the physis of long bones in response to hind limb immobilization in the rat.

BACKGROUND: The growth plate increases its activity in response to exercise. Likewise, decreased physical activity exerts a negative effect on bone growth and development, leading to rarefaction of the subepiphyseal bone. Limb immobilization inhibits the growth plate's activity, indirectly shown by a recorded arrest in longitudinal growth of the long bones. However, there is no direct evidence concerning the growth plate itself. OBJECTIVE: To determine whether the growth plate exhibits measurable microstructural changes in response to decreased levels of physical activity. METHODS: Histomorphometric analysis was used to qualitatively and quantitatively assess the changes in the epiphyseal plate in response to single hind limb immobilization in the rat. In 16 of 25 Sprague-Dawley male rats the left hind limb was immobilized for 3 weeks; the remaining 9 rats served as controls. The left proximal tibia of each animal was examined by computerized image analysis. RESULTS: There was a decrease in epiphyseal height, cell column density and subepiphyseal trabecular area--all indices of growth plate activity. Metaphyseal cortical thickness was also depressed, thereby confirming the efficacy of the immobilization method applied. CONCLUSIONS: Limb immobilization in the rat induces inhibitory histological changes in the epiphyseal growth plate, which are in contrast to the excitatory microscopic changes seen with exercise. These changes can be assessed quantitatively. Their potential for reversibility remains to be determined by future experiments.

Animals↗
PubMed1999

[Elastofibroma, a rare cause of snapping scapula syndrome].

Scapular pain is a common complaint in daily orthopedic practice. A different type of scapular discomfort, the snapping scapula syndrome that occurs when smooth gliding motion of the scapula upon the chest wall is interfered with is much less common. We studied the syndrome of periscapular pain and discomfort, and present a rare etiology: elastofibroma dorsi, a unique, benign, soft tissue-tumor with unique characteristics. Elastofibroma appears deep to the lower scapular pole, is often bilateral, and consists of a mixture of collagen, elastic fibers and fibroblasts. We present 6 cases, in 3 men and 3 women aged 51-65.

Aged↗
PubMed1998

The N-terminal domain of rat liver carnitine palmitoyltransferase 1 mediates import into the outer mitochondrial membrane and is essential for activity and malonyl-CoA sensitivity.

The rat liver carnitine palmitoyltransferase 1 (L-CPT1), an integral outer mitochondrial membrane (OMM) protein, is the key regulatory enzyme of fatty acid oxidation and is inhibited by malonyl-CoA. In vitro import of L-CPT1 into the OMM requires the presence of mitochondrial receptors and is stimulated by ATP but is membrane potential-independent. Its N-terminal domain (residues 1-150), which contains two transmembrane segments, possesses all of the information for mitochondrial targeting and OMM insertion. Deletion of this domain abrogates protein targeting, whereas its fusion to non-OMM-related proteins results in their mitochondrial targeting and OMM insertion in a manner similar to L-CPT1. Functional analysis of chimeric CPTs expressed in Saccharomyces cerevisiae shows that this domain also mediates in vivo protein insertion into the OMM. When the malonyl-CoA-insensitive CPT2 was anchored at the OMM either by a specific OMM signal anchor sequence (pOM29) or by the N-terminal domain of L-CPT1, its activity remains insensitive to malonyl-CoA inhibition. This indicates that malonyl-CoA sensitivity is an intrinsic property of L-CPT1 and that its N-terminal domain cannot confer malonyl-CoA sensitivity to CPT2. Replacement of the N-terminal domain by pOM29 results in a less folded and less active protein, which is also malonyl-CoA-insensitive. Thus, in addition to its role in mitochondrial targeting and OMM insertion, the N-terminal domain of L-CPT1 is essential to maintain an optimal conformation for both catalytic function and malonyl-CoA sensitivity.

Adenosine Triphosphate↗
PubMed1998

Incremental prognostic value of adenosine myocardial perfusion single-photon emission computed tomography in women with suspected coronary artery disease.

Adenosine myocardial perfusion single-photon emission computed tomography (SPECT) is now increasingly used for risk stratification of patients with known or suspected coronary artery disease. However, the incremental prognostic value of this test over clinical and historical information in a large series of women has not been examined. Thus, we studied 923 consecutive women who underwent adenosine technetium (Tc)-99m sestamibi myocardial perfusion SPECT and were followed-up for a mean period of 26+/-8 months. During the follow-up period, 77 hard events (46 cardiac deaths and 31 nonfatal myocardial infarctions) occurred. The results of the perfusion scan significantly risk stratified the population; patients with normal scans had a low rate of nonfatal myocardial infarction and cardiac death (< 1%/year of follow up). Patients with mildly abnormal scans had low cardiac death rates (0.9%/year of follow up); these rates increased as a function of scan abnormality (4.1% and 7.5% mortality per year of follow up in moderate and severely abnormal scans). Cox proportional hazards analysis demonstrated that after adjusting for prior myocardial infarction and diabetes mellitus (the most predictive individual clinical variables [global chi-square=22.5, p <0.001]), as well as heart rate at rest (the most predictive physiologic variable [chi-square=3.8; p=0.05]), the most predictive nuclear variable (summed stress score [chi-square=48.5; p <0.0001]) added significant incremental prognostic information (global chi-square increased from 22.5 to 56.2 [p <0.0001]). In conclusion, adenosine myocardial perfusion SPECT added significant incremental prognostic information to clinical and physiologic variables in women. Normal scans were associated with an excellent prognosis. In contrast, patients with moderately to severely abnormal scans were at a higher risk for future cardiac events.

Adenosine↗
PubMed1998

Topological and functional analysis of the rat liver carnitine palmitoyltransferase 1 expressed in Saccharomyces cerevisiae.

The rat liver carnitine palmitoyltransferase 1 (L-CPT 1) expressed in Saccharomyces cerevisiae was correctly inserted into the outer mitochondrial membrane and shared the same folded conformation as the native enzyme found in rat liver mitochondria. Comparison of the biochemical properties of the yeast-expressed L-CPT 1 with those of the native protein revealed the same detergent lability and similar sensitivity to malonyl-CoA inhibition and affinity for carnitine. Normal Michaelis-Menten kinetics towards palmitoyl-CoA were observed when careful experimental conditions were used for the CPT assay. Thus, the expression in S. cerevisiae is a valid model to study the structure-function relationships of L-CPT 1.

Animals↗