PubMed Health⌕ Search

Biomedical subjects

S Becker

Publications and source records attributed to S Becker.

At least 37 records · Page 2Linked to original sources
PubMed1991

Relative effects of diarrhea, fever, and dietary energy intake on weight gain in rural Bangladeshi children.

Quantitative studies of morbidity, food intake, and somatic growth were done prospectively during 14 mo for 70 children aged 5-18 mo in two Bangladeshi villages. When random-effect regression models were used, monthly changes in weight were inversely related to proportions of days in the month with fever and diarrhea and positively related to energy intake per kilogram body weight. Interestingly, weight changes did not vary with age in this interval. Estimates indicate that increasing energy intakes to the recommended World Health Organization level would have a significantly greater effect on weight gain than would the elimination of diarrhea and fever. With energy at recommended intake and diarrhea and fever prevalence as found in US children, weight gain is predicted to be near that of the international reference population. Therefore, interventions aimed at improving dietary intake may be as important as infection-control programs for improving growth of children in poor developing nations.

Bangladesh↗
PubMed1991

Methods compared for determining activity of N-acetyl-beta-D-glucosaminidase in urine without pretreatment of sample: different sensitivity and species effect.

N-Acetyl-beta-D-glucosaminidase (NAG) activities in the urine of men and rats were measured with methods recommended as procedures without pretreatment of the urine sample. Four different derivatives of NAG were compared for determination: 4-nitrophenyl; 3,3-dichlorophenylsulfonphthaleinyl; 3-cresolsulfonphthaleinyl, and 2-methoxy-4-(2-nitro-vinyl)phenyl. The conventional test using the 4-nitrophenyl derivative showed the highest activities and correlated very well with the other tests. There are method-dependent differences between NAG activities measured in men and rats due to the different Km values and inhibitory effects by urea.

Acetylglucosamine↗
PubMed1991

Exposure of humans to ambient levels of ozone for 6.6 hours causes cellular and biochemical changes in the lung.

An acute (2 h) exposure of humans to 0.4 ppm ozone initiates biochemical changes in the lung that result in the production of components mediating inflammation and acute lung damage as well as components having the potential to lead to long-term effects such as fibrosis. However, many people are exposed to lower levels of ozone than this, but for periods of several hours. Therefore, it is important to determine if a prolonged exposure to low levels of ozone is also capable of causing cellular and biochemical changes in the lung. Nonsmoking males were randomly exposed to filtered air and either 0.10 ppm ozone or 0.08 ppm ozone for 6.6 h with moderate exercise (40 liters/min). Bronchoalveolar lavage (BAL) was performed 18 h after each exposure, and cells and fluid were analyzed. The BAL fluid of volunteers exposed to 0.10 ppm ozone had significant increases in neutrophils (PMNs), protein, prostaglandin E2 (PGE2), fibronectin, interleukin-6 (IL-6), and lactate dehydrogenase (LDH) compared with BAL fluid from the same volunteers exposed to filtered air. In addition, there was a decrease in the ability of alveolar macrophages to phagocytize yeast via the complement receptor. Exposure to 0.08 ppm ozone resulted in significant increases in PMNs, PGE2, LDH, IL-6, alpha 1-antitrypsin, and decreased phagocytosis via the complement receptor. However, BAL fluid protein and fibronectin were no longer significantly elevated. We conclude that exposure of humans to as low a level as 0.08 ppm for 6.6 h is sufficient to initiate an inflammatory reaction in the lung.

Adolescent↗
PubMed1991

Time-dependent changes of markers associated with inflammation in the lungs of humans exposed to ambient levels of ozone.

Acute exposure of humans to 0.4 ppm ozone results in reversible respiratory function decrements, and cellular and biochemical changes leading to the production of substances which can mediate inflammation and acute lung injury. While pulmonary function decrements occur almost immediately after ozone exposure, it is not known how quickly the cellular and biochemical changes indicative of inflammation occur in humans. Changes in neutrophils and PGE2 have been observed in humans as early as 3 hr (28) and as late as 18 hr post exposure (19). The purpose of this study was to determine whether inflammatory changes occur relatively rapidly (within 1 hr) following exposure to ozone, or if the cascade of events which are initiated by ozone and lead to inflammation, take some time to develop. We exposed 10 healthy volunteers twice: once to filtered air and once to 0.4 ppm ozone. Each exposure lasted for 2 hr at an exercise level of 60 L/min, and bronchoalveolar lavage was performed 1 hr following exposure. The data from this study were compared to those from a previous study in which 10 subjects were exposed to O3 under identical conditions except that bronchoalveolar lavage was performed 18 hr following exposure. The results of the present study demonstrate that O3 is capable of inducing rapid cellular and biochemical changes in the lung. These changes were detectable as early as 1 hr following a 2 hr exposure of humans to ozone. The profiles of these changes were different at 1 hr and 18 hr following ozone exposures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Induced abortion in eight provinces of China.

A survey of 12,000 women in eight provinces of China was carried out in 1988. One urban and one rural area were selected purposely in each province; data on lifetime and recent pregnancies were collected from married women aged 20-44. Data on abortions included reasons, gestational age, and complications. During the five years before the survey, the number of abortions per 100 live births was 102 in urban areas and 62 in rural areas. For those with one or more previous live births in urban areas, nearly all subsequent pregnancies ended in abortion. Also in urban areas, 31% of women with a recent abortion reported the reason was contraceptive failure. Over 80% of women are contraceptive users; the high abortion rates then reflect relatively low use-effectiveness of contraception and that most unplanned pregnancies are aborted.

Abortion, Induced↗
PubMed1991

Multiple forms of N-acetyl-beta-D-glucosaminidase of human urine: isolation, properties and the development of a practical approach of differentiation.

The two major tissue forms of N-acetyl-beta-D-glucosaminidase, A and B, and a minor form M were isolated from human urine by chromatography on DEAE-Trisacryl M and Con A-Sepharose. Forms A and B have a Km-value of about 0.75 mM for 4-nitrophenyl-beta-2-acetamido-2-deoxy-D-glucopyranoside, form M a corresponding value of 1.57 mM. The pH optimum was for all forms between pH 4.0 and 4.8. Forms A and M were heat labile, while form B was relatively heat stable. Using different binding properties of forms A and B on Trisacryl, a batch method was developed to differentiate both forms in human urine. This method can be easily performed and gives reproducible results. The intra-run and between-run precision for the separation of the two forms were below 10%.

Acetylglucosaminidase↗
PubMed1991

Evaluation of methods for determining N-acetyl-beta-D-glucosaminidase in urine of rats without purification of urine samples.

N-Acetyl-beta-D-glucosaminidase (NAG) activities in urine of rats were measured with methods recommended as procedures without the pretreatment of urine sample. Four different derivatives [4-nitrophenyl; 3-cresolsulfonephthaleinyl; 3,3'-dichlorophenylsulfonephthaleinyl; 2-methoxy-4-(2-nitrovinyl)phenyl] of N-acetyl-beta-D-glucosaminide were compared for determination. The conventional test using the 4-nitrophenyl derivative showed the highest activities and was very well correlated with the other tests. The test using the 3,3'-dichlorophenylsulfonephthaleinyl substrate is most convenient and practical to determine NAG in small animals because it is, in contrast to the other three discontinuous (endpoint) tests, a continuous (kinetic) assay which can be easily adapted to clinical chemistry analyzers.

Acetylglucosaminidase↗
PubMed1991

[Allergic origin of recurrent middle ear effusion and adenoids in young children].

Recurrent middle ear effusions and adenoids in children might be caused by mechanical obstruction, infection or allergy. From 1989 to 1990 we examined 35 infants with no history of allergic rhinitis but with recurrent adenoids and middle ear effusions. During operation a skin test was performed for common allergens. Afterwards we tried to identify these allergens by RAST tests on tissue homogenates from the removed adenoids, the middle ear effusion and serum samples. Additionally the IgE levels were determined and the adenoid tissue was examined for eosinophils. In 12 of our 35 children (34%) the skin tests showed an allergy, mostly to different kinds of pollen or house dust. From these positive patients the respective allergens could be determined by RAST tests in serum in 84%, in tissue homogenates from the adenoids in 41% and in the middle ear effusions in 50% of cases. 50% of the children with positive skin tests showed an eosinophilia in the adenoid tissue. We did not find any allergen in the RAST of the infants with negative skin tests. The data show a correlation of allergen specific IgE antibodies in the serum of our patients and in the middle ear and the nasopharynx. Together with an eosinophilia these results suggest an allergic genesis of recurrent middle ear effusions and adenoids in about 20% to 30% of our cases. Early diagnostic procedures to rule out allergy in children with appropriate clinical symptoms are useful, and in positive cases antiallergic treatment is recommended.

Adenoids↗
PubMed1991

[Diagnostic value of the prick test and tissue RAST in allergic nasal polyposis].

Nasal polyposis is often accompanied by an allergy against inhaled allergens or various foods and drugs. We studied the relationship between nasal polyposis and type-I allergy, using a preoperative skin test on 43 patients with nasal polyposis. This was followed by RAST test of serum, nasal secretion and homogenized tissue from the polyps removed. The rest of the polyp material was examined histologically and cytologically for tissue eosinophilia. A type-I allergy was proved in 40% of the patients by the presence of the same IgE antibodies in the skin test and all the RASTs, accompanied by a distinct eosinophilia in the polyp tissue. In a further 40% of the cases most of the tests were positive, suggesting a probable allergic disposition. These results support the theory of an allergic genesis of many nasal polyps. The tissue RAST especially is of great diagnostic value. Thus, postoperative anti-allergic treatment of these patients should be successful.

Allergens↗
PubMed1990

Synthesis and characterization of an N-terminal-specific 125I-photoaffinity derivative of mu-Conotoxin GIIIA which binds to the voltage-dependent sodium channel.

An N-terminal, iodinatable photoaffinity derivative of mu-Conotoxin GIIIA, 4-Azido-salicylyl-mu-Conotoxin GIIIA (CTXASA), was synthesized by solid phase peptide synthesis. The binding of 125I-CTXASA to the voltage dependent sodium channel from electroplax of Electrophorus electricus was specific, as demonstrated by saturation binding experiments. Using autoradiography, 125I-CTXASA labeled a protein with a molecular mass of 260 kDa, consistent with the apparent molecular mass of the sodium channel. This labeling could be suppressed by excess of tetrodotoxin and mu-Conotoxin GIIIA.

Affinity Labels↗
PubMed1990

Estrogen replacement therapy and the risk of endometrial cancer: remaining controversies.

To examine the relationship between exogenous estrogen administration and endometrial cancer, we used data from the Cancer and Steroid Hormone Study, a multicenter, population-based case-control study. Estrogen replacement therapy for greater than or equal to 2 years was associated with an increased risk of both localized and extrauterine cancer (relative risk = 2.8, 95% confidence limits 1.6, 4.6; relative risk = 2.9, 95% confidence limits 0.9, 9.4, respectively). However, the latter finding was based on a small number of cases in which estrogen was used. Women who underwent estrogen replacement therapy for greater than or equal to 2 years had significantly elevated risks of endometrial cancer (2.1 for 2 to 5 years and 3.5 for greater than or equal to 6 years). An elevated risk persisted for greater than or equal to 6 years after discontinuation of therapy. Women who exclusively used conjugated equine estrogen preparations less than or equal to 0.625 mg had no increased risk of endometrial cancer. A history of oral contraceptive use appeared to reduce the risk of endometrial cancer associated with estrogen replacement therapy. However, these latter two potentially important findings were based on a small number of cases in which hormones were used.

Adult↗
PubMed1990

Antagonistic and additive effects of IL-4 and interferon-gamma on human monocytes and macrophages: effects on Fc receptors, HLA-D antigens, and superoxide production.

During an immune response a multitude of lymphokines are produced which modulate the function of mononuclear phagocytes. In this study, we investigated possible additive, synergistic, or antagonistic effects of three lymphokines, IL-4 (1-100 U/ml, 0.01-1 ng/ml), interferon-gamma (IFN) (1-100 U/ml) and IL-2 (30-300 U/ml) on Fc receptors (FcR1 and FcR2), complement receptors (CR3 and CR4), and HLA-D antigens (HLA-DR and HLA-DQ) on human monocytes and macrophages. Exposure of monocytes to IL-4 alone resulted in changes in the expression of all these receptors. Both FcR1 and FcR2 were downregulated in a dose-dependent manner while the expression of CR3, CR4, HLA-DR, and HLA-DQ was increased. Antagonistic effects of IL-4 and IFN were observed on FcR1 and FcR2; IL-4-induced downregulation of the FcR1 and FcR2 was inhibited by IFN, and vice versa, IFN-induced upregulation of FcR1 and FcR2 was inhibited by IL-4. Phagocytosis of particulate immune complexes (EAs) as well as production of superoxide (O2-) in response to EAs were inhibited by IL-4, and the inhibition was reversed by IFN. Antagonistic effects of IL-4 and IFN were also observed on CR3 and CR4 expression. Additive effects of IL-4 and IFN were on the other hand seen on HLA-DR and HLA-DQ expression as well as on O2- production in response to stimulation with phorbol ester (PMA). The addition of IL-2 to IL-4 and/or IFN-containing cultures had no further modulatory effect on receptor expression or O2- production. In vitro matured macrophages (M phi) had a similar response pattern to IL-4 and IFN as the freshly isolated monocytes. Alveolar macrophages (AM phi), on the other hand, did not modulate FcR1 and HLA-DQ in response to IL-4, and downregulated FcR2 in response to IFN. Antagonistic effects of the two factors were only seen on CR expression. These results imply that FcR expression and function on monocytes and inflammatory macrophages may be in sensitive balance with the relative concentrations of IL-4 and IFN in the immune environment. FcRs on AM phi are less responsive to modulation by these lymphokines.

HLA-DQ Antigens↗
PubMed1990

Recent evidence on trends and differentials in Bangladesh fertility.

Recent data from Bangladesh reveal evidence of some fertility decline. Although fertility increased among younger age groups between 1975 and 1983, it was offset by a decrease in fertility in the older age groups, resulting in a slight overall decrease in total fertility in 1983. Fertility was lower among urban residents, educated mothers and contraceptive users than among rural residents, uneducated mothers and contraceptive non-users, respectively, particularly in 1983.

Adolescent↗
PubMed1990

[Coping behavior and supplying medical information--a study of mothers having delivered a child with a lip-jaw-palate cleft].

To be delivered of a child with cleft lip and palate is an extreme psychic stress factor for the mother. In coping with this, she is left to the support of the caring medical staff. Therefore, the aim of the present study was 1. to ascertain, to what extent mothers of children with cleft lip and palate are given information on the malformation, and receive emotional support by the medical staff; and 2. to determine the effect such experiences have on their ability to cope. For this purpose we developed a special questionnaire, which was completed by 154 mothers of such children. Retrospectively, a relevant part of them criticised not only the communication and the contents of information, but also the emotional support as deficient. A correlation between these determinants and largely insufficient coping was statistically confirmed. Our results should be taken into account in respect of the practical requirements when caring for mothers of children with a cleft lip and palate.

Adaptation, Psychological↗
PubMed1990

Object relations in borderlines, depressives, and normals: an examination of human responses on the Rorschach.

Recently, researchers and clinicians have become increasingly interested in diagnostic distinctions between borderline and mood disorders. Object relations theory provides a useful framework for the comparison of these two overlapping diagnostic categories. In our study, a measure of object relations as represented on the Rorschach, developed by Blatt, Brenneis, Schimeck, and Glick (1976), was applied to data produced by borderline and depressive inpatients and by normal comparison subjects. Portions of the Blatt measure that tap the subject's experience of human action and interaction distinguish among the three diagnostic groups. Specifically, borderlines tend to understand human action as more highly motivated and human interaction as more malevolent in nature than do either depressive or normals. The data indicate that borderlines experience the object-relational world in a way that is fundamentally different from the way normals and depressives perceive it. Implications are discussed for theories of borderline object relations.

Adult↗
PubMed1990

Flow cytometric determination of the time of metastasis during fractionated radiation therapy of the rat rhabdomyosarcoma R1H.

A technique is presented for determining the time of metastasis during fractionated radiation therapy of the rat rhabdomyosarcoma R1H by flow cytmetric DNA index measurements. The DNA index is the relative DNA content of the tumour cells compared with normal cells. The DNA index of the highly hyperploid R1H tumour decreases linearly during radiation therapy dependent on the total dose applied, with a rate of 0.22% per Gy. Since metastatic cells escape further irradiation, their DNA index should correspond to the DNA index at time of spread. If so, cells disseminated late during a course of fractionated irradiation are expected to produce symptoms later and to have a lower DNA index compared with cells that metastasized at the start of treatment. The results obtained fitted these expectations, showing that timing of metastases by DNA flow cytometry, in principle, is possible. A first application of this method indicates that the risk per clonogenic R1H tumour cell to matastasize increases during fractionated irradiation.

Animals↗
PubMed1990

Characterization of normal human lung lymphocytes and interleukin-2-induced lung T cell lines.

Lymphocytes from the lower respiratory tract were obtained by bronchoalveolar lavage of healthy, non-smoking individuals. Various monoclonal antibodies characterizing activated T cells, helper-inducer and suppressor-inducer T cell subsets, and naive versus memory cells were used to define the phenotype of these lymphocytes. The highly variable CD4/CD8 ratio (0.3 to 6.6; mean = 2.1) and the large proportion of the T cells expressing HLA-DR (9 to 38%; mean = 21%) suggested that the T cells were recently activated by antigens selectively stimulating either helper or cytotoxic/suppressor T cell function. Indeed, the CD45RA antigen, a marker characteristic of suppressor-inducer T cells when coexpressed with CD4, and naive T cells in general, was absent from T cells in most preparations (0 to 17%; mean = 5%), while the CD45RO antigen, a marker of memory cells and immature thymocytes, was present on 68 to 100% of all lung T cells. The majority (greater than 70%) of the CD4+ helper T cells was CD45RO+ CD45RA-, a phenotype found on T cells that provide help for B cell immunoglobulin synthesis. Lung T cells proliferated poorly in response to phytohemagglutinin and concanavalin A but did respond to activation with low concentrations of anti-CD3 mAb (2 to 25 ng/ml) and to interleukin-2 (IL-2) alone to similar extent as did autologous peripheral blood lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗