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Biomedical subjects

J Beck

Publications and source records attributed to J Beck.

At least 181 records · Page 10Linked to original sources
PubMed1992

The ergonomic challenge of repetitive motion with varying ergonomic stresses. Characterizing supermarket checking work.

Many jobs leading to a risk of cumulative trauma do not have highly stereotyped motions. This study developed and employed a novel method of ergonomic characterization to describe quantitatively the actions associated with grocery checking. Fifty workers were videotaped for three 15-minute segments each. Eight object types were selected to represent the variety of items in a supermarket. Nine types of motion were coded for each of the eight objects for 10 replications for each subject. The motions coded were: grip type (power versus pinch), wrist flexion, wrist extension, radial deviation, ulnar deviation, supination, pronation, body (lumbar) flexion, and drag versus lift. The results were then weighted according to relative frequency of the object type. In this manner, an ergonomic risk index can be assigned to each specific object type. This method permits identification of objects presenting the greatest risk. It also allows specificity of preventive interventions (object redesign, work practice change) as well as providing a quantitative measure to evaluate work station redesign. Furthermore, it has the potential of quantitatively describing the risk of each individual worker.

Cumulative Trauma Disorders↗
PubMed1992

Achieving local control for inflammatory carcinoma of the breast.

A single institution, retrospective study of 28 patients with inflammatory carcinoma of the breast treated from 1984 to 1990 was performed. Patients received two to four cycles of cyclophosphamide, doxorubicin and 5-fluorouracil (CDF) and were then evaluated for mastectomy. Mastectomy was accomplished in 26 patients after CDF. In 21 patients, the breast was resectable after the initial doses of chemotherapy and modified radical mastectomy was done. Radiation therapy was given to 16 of the 21 patients after six to nine cycles of postoperative chemotherapy. The remaining five of 26 patients had a marginal response to CDF and underwent preoperative radiation therapy. Local recurrence occurred in four of five patients receiving preoperative radiation, in three of 16 receiving postoperative radiation and in one of five receiving mastectomy without radiation therapy. The overall observed five year survival rate was 18 percent, with a median of 34 months. Neither dermal lymphatic invasion nor estrogen receptor status were statistically significant variables when analyzing patients for local recurrence or survival. Despite poor long term survival results, the combination of induction CDF, mastectomy and postoperative radiation achieved local control in 81 percent of patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Structural and functional conservation of histidinol dehydrogenase between plants and microbes.

The partial amino acid sequence of histidinol dehydrogenase (L-histidinol:NAD+ oxidoreductase, EC 1.1.1.23) from cabbage was determined from peptide fragments of the purified protein. The relative positions of these peptides were deduced by aligning their sequences with the sequence of the HIS4C gene product of Saccharomyces cerevisiae. cDNA encoding histidinol dehydrogenase was then amplified from a library using a polymerase chain reaction primed with degenerate oligonucleotide pools of known position and orientation. By using this amplified fragment as a probe, an apparently full-length cDNA clone was isolated that is predicted to encode a proenzyme having a putative 31-amino acid chloroplast transit peptide and a mature molecular mass of 47.5 kDa. The predicted protein sequence was 51% identical to the yeast enzyme and 49% identical to the Escherichia coli enzyme. Expression of the cDNA clone in an E. coli his operon deletion strain rendered the mutant able to grow in the presence of histidinol.

Alcohol Oxidoreductases↗
PubMed1991

The lack of receptors for atrial natriuretic peptides on human monocytes prevents a rise of cGMP and induction of tumor necrosis factor-alpha synthesis.

Freshly harvested human monocytes were shown to produce tumor necrosis factor-alpha (TNF-alpha) in response to exogenously added or sodium nitroprusside-generated cGMP. In contrast, atrial natriuretic peptide (ANP) that acts by elevating cGMP in a variety of cells, was incapable of inducing TNF-alpha synthesis. This failure was due to a lack of ANP receptors and thus, to the inability of ANP to raise cGMP in human monocytes.

Atrial Natriuretic Factor↗
PubMed1991

Regulated expression allows high level production and secretion of HIV-1 gp120 envelope glycoprotein in Drosophila Schneider cells.

We have established a stable, continuous culture Drosophila Schneider 2 cell line that efficiently expresses a secreted, truncated form of the HIV envelope gp120 protein in a regulated manner. The Drosophila produced recombinant gp120 protein is highly glycosylated, is recognized by gp120-specific monoclonal antibodies, binds to the CD4 receptor and has the ability to inhibit syncytia formation between uninfected CD4+ cells and HIV infected cells. We conclude that this recombinant Drosophila envelope protein is an appropriate mimic of the authentic viral envelope protein. Thus, the Drosophila cell provides a continuous, stable culture system for the efficient expression of secreted forms of complex surface glycoproteins in quantities sufficient for detailed analyses.

Amino Acid Sequence↗
PubMed1991

Physiologic and subjective effects of respirator mask type.

The effect of alternate airflow path designs on full-face mask air-purifying respirators was assessed in 14 healthy volunteers during submaximal exercise. Respirator designs included no respirator (N), full-face mask, dual-cartridge with no nasal deflector (FN), full-face mask respirator with nasal deflector (FD), and a powered air-purifying respirator (PA). Physiologic effects were measured by using respiratory inductive plethysmography and subjective responses by two visual analog scales. There were significant effects of airflow path design upon the physiologic parameters of ventilation, tidal volume, and mean flow rate. There were no significant physiologic or subjective differences between the full-face mask respirators with and without the nasal deflector in place. The PA had less physiologic impact than the nonpowered models but did not show significant subjective benefit. The study suggests that both subjective and objective physiologic responses must be utilized in assessing respirator design.

Adult↗
PubMed1991

TGF-beta-like activity produced during regression of exacerbations in multiple sclerosis.

Samples representative of different stages of disease from a longitudinal study of multiple sclerosis patients were tested in the anchorage-independent growth assay for TGF-beta and an increased activity was detected in the supernatants from 2-day blood cell cultures from patients with active disease compared to patients without active disease and healthy donors. Within the group of patients with active disease, the TGF-beta like activity was significantly increased in the subgroup of patients tested during the period of regression of the symptoms where it appeared in 86.9% of the samples. These results suggest that TGF-beta or a TGF-beta like factor may play a role in regeneration processes in multiple sclerosis.

Adrenal Cortex Hormones↗
PubMed1991

Lightness differences and the perceived segregation of regions and populations.

A striking finding reported by Beck, Sutter, and Ivry (1987) was that, in textures composed of regions differentiated by the arrangement (checks and stripes) of two texture elements (light and dark squares), a large lightness difference between the squares could fail to yield segregation between the regions, whereas a smaller lightness difference could sometimes yield strong segregation. In the experiments reported here, we compared the segregation of striped and checked arrangements of light and dark squares into regions with the segregation of two randomly interspersed populations of light and dark squares into subpopulations. Perceived lightnesses are the same for a given set of squares, whether they are arranged in regions or in intermixed populations. Perceived population segregation is approximately a single-valued function of the lightness differences of the squares, but perceived region segregation is not. The reason for the difference between population segregation and region segregation may be that region segregation is mediated by detectors' having large oriented receptive fields (large bar detectors) that are sensitive to the fundamental spatial frequency and orientation of the texture region as defined by the arrangement of the squares (Beck et al., 1987; Sutter, Beck, & Graham, 1989). These detectors cannot be responsible for population segregation, because the light and dark squares are distributed randomly throughout these patterns and therefore do not define a consistent arrangement of any particular spatial frequency or orientation. The light and dark squares in the population patterns fall equally on excitatory and inhibitory regions of large bar detectors. A plausible explanation for population segregation is to suppose that the segregation is the result of similarity grouping of the light and dark squares.

Contrast Sensitivity↗
PubMed1991

Hydrocolloid occlusion for the treatment of neurovascular corns.

The goal of this study was to determine the effect of hydrocolloid occlusion on neurovascular corns. The design was an observer-blinded, randomized, controlled study. Thirty consecutive patients participated in the trial. The patients received curettage alone or curettage with hydrocolloid occlusion. Six treatments were given over 12 weeks. A follow-up examination was performed 3 months after termination of the trial. Outcome measures were the size of the corns, a discomfort score, and an overall judgment of the trial. The results demonstrated no benefit of occlusion for symptoms or signs of neurovascular corns. The patients treated with occlusion were, however, generally more satisfied than the conventional group.

Aged↗
PubMed1991

Relative effects of flow-resistive and pressure-biased respiratory loading.

The effects of pressure-biased breathing (PBB), which simulates positive pressure respirator use, were studied in 15 volunteer subjects during laboratory exercise. PBB was compared with inspiratory resistance: dead space (ID) load and a no-load (N) situation. PBB had adverse subjective effects comparable with those of ID. Physiologically, PBB led to a small decrease in inspiratory time and an increase in expiratory time as well as an increase in the intensity of ventilatory effort as measured by the mean inspiratory flow rate. It is postulated, based on these findings, that PBB has significant effects on the resting lung volume, leading to both physiologic and subjective consequences.

Adult↗
PubMed1991

[Semiautomatic preparation of anesthesia records using the DATATRAC].

In this paper we report on our experience with clinical use of the electronic clipboard DATATRAC, which is designed for semiautomatic recording during anesthesia, i.e., for automated recording of cardiocirculatory parameters during anesthesia. In a period of 3 years, about 50 and 800 DATATRAC anesthesia records have been produced during vascular surgery and ophthalmic surgery, respectively. We discuss the advantages and short-comings of this type of anesthesia recording and the objections raised to it, and we analyze the malfunctions that can occur and their significance.

Anesthesiology↗
PubMed1990

The multifunctional 6-methylsalicylic acid synthase gene of Penicillium patulum. Its gene structure relative to that of other polyketide synthases.

6-Methylsalicylic acid synthase (MSAS) from Penicillium patulum is a homomultimer of a single, multifunctional protein subunit. The enzyme is induced, at the transcriptional level, during the end of the logarithmic growth phase. After approximately 150-fold purification, a homogeneous enzyme preparation was obtained exhibiting, upon SDS gel electrophoresis, a subunit molecular mass of 188 kDa. By immunological screening of a genomic P. patulum DNA expression library, the MSAS gene together with its flanking sequences was isolated; 7131 base pairs of the cloned genomic DNA were sequenced. Within this sequence the MSAS gene was identified as a 5322-bp-long open reading frame coding for a protein of 1774 amino acids and 190,731 Da molecular mass. Transcriptional initiation and termination sites were determined both by primer extension studies and from cDNA sequences specially prepared for the 5' and 3' portions of the gene. The same cDNA sequences revealed the presence of a 69-bp intron within the N-terminal part of the MSAS gene. The intron contains the canonical GT and AG dinucleotides at its 5'- and 3'-splice junctions. An internal TACTGAC sequence, resembling the TACTAAC consensus element of Saccharomyces cerevisiae introns is suggested to represent the branch point of the lariat splicing intermediate. When compared to other known polyketide synthases, distinct amino acid sequence similarities of limited lengths were observed with some, though not all, of them. A comparatively low degree of similarity was detected to the yeast and Penicillium FAS or to the plant chalcone and resveratrol synthases. In contrast, a significantly higher sequence similarity was found between MSAS and the rat fatty acid synthase, especially at their transacylase, 2-oxoacyl reductase, 2-oxoacyl synthase and acyl carrier protein domains. Besides several dissimilar, interspersed regions probably coding for MSAS- and FAS-specific functions, the sequential order of the similar domains was colinear in both enzymes. The low similarity between the two P. patulum polyketide synthases, MSAS and FAS, possibly supports a convergent rather than a divergent evolution of both multienzyme proteins.

Acyltransferases↗
PubMed1990

Further serial transmission electron microscopy studies of auditory hair cell innervation in lizards and in a snake.

Auditory hair cells of three lizard and one snake species were studied by serial transmission electron microscopy (TEM) sections of two unidirectional hair cells (UHC) and two bidirectional hair cells (BHC) and by nonserial section montages of each entire papilla cut at 2-microns intervals across the papillar width. The unidirectional hair cell region of the agamid lizard, Acanthosaura crucigera, lacked efferent innervation. Another agamid lizard, Agama agama, studied by nonserial section only, also lacked efferent innervation to the UHC. Afferent innervation to both the UHC and BHC of Acanthosaura was primarily exclusive (each nerve fiber innervates only one hair cell), although an occasional nerve fiber innervated two hair cells. Both the UHC and the BHC of the anguid, Celestus costatus, were exclusively innervated. Both hair cell types of the varanid, Varanus exanthematicus, were nonexclusively innervated (all afferent nerve fibers innervate two or more hair cells). The auditory papilla of the colubrid snake, Elaphe obsoleta, has only one type of hair cell and each is nonexclusively innervated. The numbers of afferent and efferent nerve fibers and of afferent synapses are presented in tabular form.

Animals↗
PubMed1990

Formation of acids, lactones and esters through the Maillard reaction.

From a glucose/glycine reaction mixture acids, esters and lactones were isolated and identified. Sugar degradation products could also be determined as benzimidazole derivatives after reaction with o-phenylenediamine. Results derived from model systems suggested possible reaction pathways leading to some of the isolated substances. A lactic acid ester is formed as a product of an unstable beta-pyranone intermediate. A 3-deoxyhexosone serves as a precursor of two furanolactones.

Acids↗
PubMed1990

Isolation of complementary DNA clones encoding pathogenesis-related proteins P and Q, two acidic chitinases from tobacco.

Complementary DNA clones encoding two isoforms of the acidic endochitinase (chitinase, EC 3.2.1.14) from tobacco were isolated. Comparison of amino acid sequences deduced from the cDNA clones and the sequence of peptides derived from purified proteins show that these clones encode the pathogenesis-related proteins PR-P and PR-Q. The cDNA inserts were not homologous to either the bacterial form of chitinase or the form from cucumber but shared significant homology to the basic form of chitinase from tobacco and bean. The acidic isoforms of tobacco chitinase did not contain the amino-terminal, cysteine-rich "hevein" domain found in the basic isoforms, indicating that this domain, which binds chitin, is not essential for chitinolytic activity. The accumulation of mRNA for the pathogenesis-related proteins PR-1, PR-R, PR-P, and PR-Q in Xanthi.nc tobacco leaves following infection with tobacco mosaic virus was measured by primer extension. The results indicate that the induction of these proteins during the local necrotic lesion response to the virus is coordinated at the mRNA level.

Amino Acid Sequence↗
PubMed1990

Syndrome comorbidity in patients with major depression or dysthymia: prevalence and temporal relationships.

The authors administered the Structured Clinical Interview for DSM-III-R to 260 patients with principal diagnoses of depressive disorders. Approximately two-thirds of these patients were given at least one additional concurrent axis I disorder. The most common comorbid diagnoses were anxiety disorders. The depressive disorders preceded the anxiety disorders in most patients. The authors not only point out the scientific and clinical implications of psychiatric comorbidity in view of the patterns of comorbidity found in this and previous studies but also discuss issues in comorbidity research.

Adult↗