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Biomedical subjects

D Heller

Publications and source records attributed to D Heller.

At least 37 records · Page 2Linked to original sources
PubMed2000

Predictors of ovarian follicle number.

OBJECTIVE: To identify factors associated with ovarian follicle density in women of reproductive age. DESIGN: Women undergoing incidental oophorectomy responded to structured interviews. Grossly normal ovaries were sectioned and assessed for follicle density. SETTING: University hospital. PATIENT(S): 102 women undergoing hysterectomy with incidental oophorectomy who had morphologically normal ovaries. MAIN OUTCOME MEASURE(S): Follicle density, age, parity, oral contraceptive use, body size, smoking, and alcohol consumption. RESULT(S): Follicle density decreased with age and with current or past cigarette smoking. Other factors were not associated with follicle density, although the study had adequate power to detect only strong associations. CONCLUSION(S): Some of the adverse effects of smoking on reproductive health may be due to irreversible follicular depletion.

Adult↗
PubMed2000

[The importance of the endogenous cannabinoid system in various neuropsychiatric disorders].

The endogenous cannabinoid system was first described in 1988. There are two specific receptors, the CB2-receptor, located in the lymphatic system (spleen, lymphocytes), and the CB1-receptor occurring predominantly in the central nervous system. The CB1-receptor shows a distinct distribution in the CNS with a very high density in the cerebellum, the basal ganglia and in the hippocampus. In 1992 endogenous ligands of the cannabinoid system were discovered for the first time (e.g. anandamide and 2-arachidonylglycerol). The physiological role of these arachidonic acid derivates is still unclear. Implications of these recent discoveries for the Gilles de la Tourette syndrome, ischaemic brain lesions, schizophrenic psychoses and opiate drug dependence are described. A dysregulation in the endogenous cannabinoid/anandamide system could possibly play an import role in the etiology of Gilles de la Tourette syndrome and schizophrenic psychoses; administration of cannabinoids affects the symptoms of the Gilles de la Tourette syndrome positively, whereas cannabinoids probably have rather negative effects in schizophrenic psychoses. In ischaemic brain lesions cannabinoids seem to have a neuroprotective effect; they appear to minimize the extent of a lesion by reduction of glutamate release. Additionally the meaning of the endogenous cannabinoid system for the development of opioid drug dependency is discussed and interactions between the endogenous opioid system and the endogenous cannabainoid system are pointed out. This is of interest since it could be shown in animal experiments that the absence of CB1 receptors reduces the positive reinforcement of opiate administration.

Animals↗
PubMed2000

Risk factors for hyperplasia-associated versus atrophy-associated endometrial carcinoma.

OBJECTIVE: Endometrial cancer can be divided into atrophy-associated and hyperplasia-associated subtypes. It has been suggested that these subtypes have different pathologic features and prognoses. This preliminary study explores whether these subtypes are associated with different risk factors. STUDY DESIGN: Hysterectomies performed in cases of endometrial carcinoma with evaluable benign endometrium on routine processing were reviewed, and clinical data were abstracted from medical records. Forty-eight subjects with atrophy-associated and 28 subjects with hyperplasia-associated cancers were studied. RESULTS: We found younger age, higher weight, absence of cigarette smoking, and earlier menarche in subjects with hyperplasia-related cancers. CONCLUSIONS: Our findings support the idea that hyperplasia-associated endometrial cancer is estrogen-related but also suggest that atrophy-associated cases may result from a different causal pathway. Epidemiologic studies may yield more precise and accurate measures of association if atrophy-associated and hyperplasia-associated endometrial cancers are considered separately.

Adenocarcinoma↗
PubMed2000

Luteal progesterone relates to histological endometrial maturation in fertile women.

To examine the relationship between endometrial histological maturation and reproductive hormones, we studied 11 fertile women, aged 18-37 yr. All participants had had at least 1 previous pregnancy and cycled regularly, every 25-35 days. Women collected daily, first morning voided urine for measurement of estradiol and progesterone metabolite excretion, estrone conjugates (E1c), and pregnanediol glucuronide (Pdg), respectively, throughout the cycle of study. Hormones were normalized for creatinine. Between 7-9 days after home detection of a LH surge (Sure Step), participants underwent an endometrial biopsy using a small bore (Pipelle) catheter. Tissue was prepared for histological and biochemical analyses. The histological analysis is reported herein. Endometrium was dated by 3 authors (N.S., D.H., and S.P.), all of whom were blinded to the participant's identity or timing of biopsy within her cycle. Final dating was agreed upon based upon the method of Noyes et al. E1c and Pdg were integrated throughout the cycle using the trapezoidal rule, and correlations were sought between deviation from expected histology (based upon urinary hormones and LH surge) and integrated hormone values. E1c varied over a 2-fold range in these normal women, from 1196-2040 ng/cycle. Pdg excretion was much more variable, ranging from 22-119 microg/cycle. No relationship could be found between histological lagging of endometrial maturation and lower excretion of E1c. A moderate correlation was observed (Spearman's r = 0.6; P < 0.05) between degree of histological maturation and integrated Pdg. Of two women with evidence of a disparity between gland and stromal development (glands lagging behind stroma by >2 days), one excreted 24 microg Pdg/cycle, the next to lowest value. We conclude that normal fertile women experience a wide range of hormone concentrations in the face of normal endometrial maturation. Progesterone appears to exert a dose-related effect on endometrial maturation, and the techniques we used, although relatively crude clinical measures, appeared to be sufficient to detect this relationship.

Adolescent↗
PubMed1999

Lateral masking: limitations of the feature interaction account.

Recognition performance for a target letter embedded in a string of characters is worse than that for targets presented in isolation. This lateral masking (LM) effect is known to depend on target eccentricity and spacing between target and flankers (Bouma, 1970), indicating that LM arises in early visual processing due to interactions among visual features. The feature interaction account would predict that flankers consisting of similar features produce similar LM effects and that differences in LM produced by different types of flanker diminish with increasing target eccentricity and decreasing spacing. However, in a series of six experiments, this prediction was shown not to be true. Flankers that did not access a higher level code (e.g., pseudoletters or rotated letters) produced more LM than standard letter flankers. Moreover, effects of different flanker types were most pronounced for medium target eccentricities and medium spacings for which recognition performance scores ranged between 40% and 60%.

Adult↗
PubMed1999

[Determining the emission of microorganisms from biofilters and emission concentrations at the site of composting areas].

In order to assess source emissions and dispersal of airborne culturable microorganisms from composting plants, measurements at three composting plants have been carried out. The downwind concentrations of dispersed microorganisms differed greatly, depending on the type of plant design. At 200 metres downwind from the totally enclosed composting plant, levels of spore concentrations of thermotolerant fungi and Aspergillus fumigatus, which may be regarded as characteristic for composting operations, were not above the magnitude of background concentrations. In contrast, spore concentrations in excess of the background level occurred within 500 metres of the partly open plant. Moreover, the ranges of airborne concentrations at similar distances from the enclosed plant were much smaller relative to the partly open plant. Measurement of source emissions from biofilters showed concentrations in the raw and purified gases in the range of up to three orders of magnitude. The operational characteristics of the plants generally contributing to bioaerosol emissions on-site were found to have an influence on the concentration levels in the raw gas. A decrease in the microbiological parameters which may be regarded as specific for composting operations, was attributed to a reduced rate of passage through the biofilters. The magnitude of reduction as well as the concentrations varied greatly.

Air Microbiology↗
PubMed1998

Stunting syndrome in broilers: effect of stunting syndrome inoculum obtained from stunting syndrome affected broilers, on broilers, leghorns and turkey poults.

Responses to stunting syndrome (SS) infective material obtained from affected broilers and administered per os were monitored for 3 wk in a fast-growing commercial broiler population, in slow-growing Leghorn chicks, and in turkey poults. At 2 and 3 wk, the size of the gastrointestinal tract (GIT) segments, the pH of the GIT contents, and the activities of digestive enzymes in the intestinal contents and of disaccharidases on the jejunum mucosae were determined. Inoculation affected the genetic stocks differently. In broiler chicks, growth and feed utilization were markedly reduced. In contrast, inoculation of Leghorns was accompanied by improved feed intake and growth rate. Performance of poults was affected only slightly, albeit significantly. The effect of inoculation on the pH of crop and intestinal contents in Leghorn chicks was opposite to that found in broiler chicks, i.e., a significant increase in the crop and small intestinal pH in the former vs a significant decrease in inoculated broilers. Although inoculation of the broiler chicks did not affect the pH in the proventriculus, in Leghorn chicks it was reduced by 25%. In poults, inoculation did not significantly affect GIT contents pH. The GIT segments were markedly enlarged in broiler chicks, whereas in Leghorn chicks the opposite trend was observed; namely, intestinal segment weights were significantly reduced. In poults, inoculation caused a reduction in the intestinal segments and gizzard weight at 3 wk. During this same period, the liver and pancreas relative weights were dramatically increased in broiler chicks. A higher relative heart weight at 2 wk was observed in broilers and poults; this trend persisted to Week 3 in poults but not in broiler chicks. In broiler chicks, a nonsignificant reduction was observed for all enzymes assayed at 3 wk and for chymotrypsin at 2 wk. In Leghorn chicks, inoculation was accompanied by a marked and significant increase in the activity of chymotrypsin during both periods. In poults, inoculation caused a marked increase in the activities of amylase during Week 2 and 3, and trypsin at 3 wk. Maltase and saccharase activities in the jejunum of broiler chicks were slightly depressed a t 2 and 3 wk, the depression being significant at 2 wk for maltase and at 3 wk for saccharase. In the Leghorn chicks, inoculation caused a twofold increase in the activities of both enzymes. As in Leghorns, inoculation of poults with SS infective material caused a marked increase in the activities of the disaccharidases. The different responses to SS inoculation in the different genetic stocks are discussed.

Animals↗
PubMed1998

LifeLines: using visualization to enhance navigation and analysis of patient records.

LifeLines provide a general visualization environment for personal histories. We explore its use for clinical patient records. A Java user interface is described, which presents a one-screen overview of a computerized patient record using timelines. Problems, diagnoses, test results or medications can be represented as dots or horizontal lines. Zooming provides more details; line color and thickness illustrate relationships or significance. The visual display acts as a giant menu, giving direct access to the data.

Humans↗
PubMed1997

Scopes of perception: the experimental manipulation of space and time.

Discussions of space and time have been grist to the philosophers' mill for centuries. We argue that the evolution of psychology as an independent discipline was in part a consequence of addressing philosophical questions concerning the perception of space and time by recourse to experiment rather than exposition. Two initially separate factors assisted in establishing this independence. On the one hand, it was driven by the invention of instruments for stimulus control so that the methods of physics could be applied to the study of perceptual phenomena. On the other hand and somewhat later, it was followed by the development of psychophysical methods, which opened the possibility of quantifying the responses to such controlled stimulation. The principal instruments were invented in the first half of the nineteenth century, and they consisted of simple contrivances that manipulated time and space in ways that had not previously been appreciated. This article examines the devices that were invented, like stroboscopes, anorthoscopes, stereoscopes, tachistoscopes, chronoscopes, and more recently oscilloscopes, and the ways in which they influenced the scope of perceptual psychology in the past as well as in the present. In contemporary experimental psychology all these instruments have been replaced by the computer. While it has extended the scope of experiments even further it has introduced a new set of limitations.

History, 18th Century↗
PubMed1997

Ovarian steroid cell tumors: sonographic characteristics.

The goal of the gynecologist is to detect ovarian tumors in their earliest stages. Small virilizing tumors, which barely affect the size of the ovaries, are such lesions. Since the introduction of transvaginal sonography it is technically possible to detect small intraovarian neoplasms. Three cases of virilizing steroid cell tumors in postmenopausal women with ovarian volumes just exceeding the normal sizes for age are presented. High-frequency transvaginal ultrasound and color Doppler studies to measure flow parameters were used. These small tumors had different echogenicity from the surrounding ovarian tissue and two had low impedance-to-flow values. Gray-scale transvaginal sonography combined with color Doppler studies can make the diagnosis of small steroid cell tumors easier and, at times, better than other, more costly imaging modalities.

Aged↗
PubMed1997

Levels and role of cytokines in bovine leukemia virus (BLV) infection.

Bovine leukemia virus belongs to a small subfamily of exogenous retroviruses that includes the human retroviruses HTLV-1, HTLV-II and the simian virus, STLV-1. Like other retroviruses, infection with BLV results in deregulation of the host immune system at both humoral and cellular levels. An approach which might help in the elucidation of some immune impairment phenomena is the investigation of the role that cytokines play in the pathogenesis and immune response of BLV infected animals. Here we describe our findings on IL-6 and TNF. We have found that the levels of IL-6 in the sera of BLV infected cows which show persistent lymphocytosis (BLV+ PL+) were significantly higher than those of BLV infected with no lymphocytosis (BLV+ PL-) or BLV negative cows (BLV-). The same results were obtained by measuring the spontaneous production of IL-6 in peripheral blood mononuclear cells (PBMC). Furthermore, PBMC derived from BLV+PL+ cows secrete higher levels of IL-6 and TNF alpha than those derived from BLV+PL- and BLV- ones following in vitro exposure to the BLV gp51 antigen, bacterial endotoxins (LPS) and ConA. Similar results were obtained when supernatants from stimulated adherent (monocytes, macrophages) and non-adherent cells (B and T lymphocytes) were tested. When exogenous IL-6 and TNF alpha were added to BLV infected cells in vitro, the expression of viral antigens was strongly suppressed. Thus, the possibility exists that the elevated production of IL-6 and even more than that of TNF alpha play a role as contributing factors to the latency of the clinical expression in BLV infection.

Animals↗
PubMed1996

Chronic lymphocytic leukemia in pregnancy.

Chronic lymphocytic leukemia, a disease predominantly of elderly men, was incidentally diagnosed in a young pregnant patient. She did not require any chemotherapy and had a normal pregnancy outcome. However, she had repeated episodes of respiratory tract infections and anemia that required multiple antibiotics and transfusions. The placenta showed increased numbers of mature-appearing lymphocytes in the intervillous space, consistent with the diagnosis of chronic lymphocytic leukemia. To our knowledge this is the first reported case of chronic lymphocytic leukemia in pregnancy.

Adult↗
PubMed1996

Tamoxifen-induced growth of leiomyomas. A case report.

BACKGROUND: Tamoxifen, a nonsteroidal estrogen agonist-antagonist, is used in the treatment of breast cancer. CASE: A postmenopausal woman, aged 73, while being treated with Tamoxifen, developed continuous growth of her myomatous uterus, became symptomatic and required surgery. CONCLUSION: Tamoxifen at a dose of 40 mg/d has been associated with endometrial carcinoma. The growth of myomas seen with Tamoxifen in this patient seems to be a result of its direct agonist properties.

Aged↗