Biomedical subjects
Publications and source records attributed to G Baum.
An essential first step in the purification of monoclonal antibodies is the clarification of the ascites fluid. While not ignored, this step has not received critical attention. Six different procedures were evaluated with respect to effectiveness and impact on several selected chemical components. For large-scale work, we find an on-line filtration process to be most efficient.
The expression of the different tropomyosin isoforms was analyzed in primary granulosa cell cultures and in established granulosa cell lines cotransfected with SV40 and Ha-ras DNA which retain a high steroidogenic response to cAMP stimulation. In contrast to normal cells which greatly reduce the expression of all tropomyosin isoforms during development of steroidogenic ability, in the doubly transformed cells only the synthesis of the high molecular weight isoforms nos 2 and 3 was decreased. The expression of isoforms 1 and 5 was elevated in the cotransfected lines and that of tropomyosin 1 was further enhanced by cAMP stimulation. The increased synthesis of tropomyosins 1 and 5 is unique to SV40 transformation, since it was observed also in cells transfected with SV40 DNA alone. These cells displayed a well organized microfilament system, but have lost the ability to differentiate. The reduced expression of tropomyosins 2 and 3 and a poorly organized microfilament system appear to be a dominant feature of both the highly differentiated normal- and transformed-granulosa cells. It is suggested that the switches in tropomyosin isoform expression during development of the steroidogenic phenotype and in cell transformation may account for necessary changes in microfilament organization which accompany these cellular processes.
Granulosa cell differentiation in vitro in response to gonadotropins is characterized by major changes in cell shape, cell aggregation, and the organization of microfilaments. These changes are associated with enhanced steroidogenesis in maturing granulosa-lutein cells. Since nonmuscle tropomyosin isoforms were implicated in stabilizing actin filaments, we studied the organization and expression of tropomyosin in differentiating primary cultures of rat granulosa cells and during ovarian folliculogenesis and luteinization. In unstimulated primary granulosa cell cultures tropomyosin was found mainly along stress fibers. In differentiating cells tropomyosin staining was diffuse with sometimes a subcortical organization. The changes in tropomyosin organization were accompanied by a pronounced decrease in the synthesis, translation in vitro, and mRNA levels of all the rat nonmuscle tropomyosin isoforms, with a greater reduction in the higher molecular weight isoforms than in the smaller isoforms. Similar results were obtained whether cells were stimulated to differentiate with gonadotropins, with cAMP, by culturing cells on an extracellular matrix, or by treatment with cytochalasin B. The effect of cytochalasin B was reversible; upon removal of the drug tropomyosin synthesis increased to near control levels, while that of proteins associated with luteinization decreased drastically. RNA isolated from ovaries with follicles at the preantral, preovulatory stage and from corpora lutea contained decreased tropomyosin mRNA levels during ovarian luteinization when the level of RNA for a key steroidogenic enzyme, cytochrome P-450 cholesterol side chain cleavage (P-450 scc), increased. The results suggest a physiological relevance for the low level of tropomyosin expression in the mechanisms which bring about the morphological and biochemical development and maturation of granulosa cells.
This prospective study was initiated 3 years ago to evaluate the outcome and to identify predictors of success or failure in patients admitted to a rehabilitation program for chronic low-back pain. Multiple parameters were evaluated, including psychologic data (MMPI, personal interview, pain drawing, etc.), physical measurements (flexibility, strength and endurance), and demographic data concerning the patient's home and working environment. Information was available on each patient admitted to the program prior to his admission, at completion of the program, 6 weeks following completion of the program and 3 months following completion of the program. A telephone interview was carried out 2 1/2 years following the patient's discharge from the program. Linear regression analysis was used to identify the important independent variables with regard to the dependent variables of relief of back pain, return to work and increased activities at home. Demographic data were of no value as a predictor with the exception of age and returning to work. The patients over the age of 50 returned to work with much less frequency than those less than 50. Psychologic information from the MMPI and similar tests were of no value. The personal preadmission interview of a trained psychologist, however, was a good predictor of an individual's eventual return to work and overall improvement. Worker's Compensation and other litigation was a negative factor in a patient's prognosis. The treatment team's prognosis at the time of discharge from the program was the best overall predictor of a patient's chance of success or failure in the longterm.
Toxic protein metabolites are assumed to play an important role in the multifactorial pathogenesis of hepatic encephalopathy (HE). To investigate this, we examined the serum levels of free amino acids, free phenols and indoles in 100 healthy adults, and in 124 liver cirrhotics with HE and 80 without HE. We found a significant increase in free serum phenols and indican already in liver cirrhosis without portal hypertension (PH) and HE. In stage III and IV HE large amounts of p-hydroxy-phenyl lactic acid were detected, which was not the case in cirrhotics without HE. In HE the increase in free serum phenols and indican was much higher than that of the mother substances tyrosine and tryptophan. The quotient BCAA/AAA was decreased significantly already in PH without HE. In addition to the increased formation by intestinal bacteria, a diminished oxidative capacity of the cirrhotic liver seems to be one of the main causes of the increased serum levels of toxic protein metabolites in HE.
This article compared the ability of four dedicated ultrasound breast scanners to display the texture, location, size, and shape of pseudo-tumors, cysts, dilated ducts, and microcalcifications in a breast phantom. Each instrument required adjustment to display the structures in the breast phantom because of the difference in acoustic impedance of the materials in the phantom versus tissue. Two Technicare instruments, one Life Imaging instrument, and a laboratory designed and constructed ultrasound breast scanner were used in this study. The laboratory instrument was able to visualize the targets with simple sector scanning. One Technicare instrument that could only perform simple sector scanning could only visualize a target just below the nipple, i.e., a dilated duct. The second Technicare instrument, which had a modified arc scan, could visualize all the targets except a 12.7-mm cyst, 9 cm posterior to the nipple. The Life Imaging unit could not detect the targets with sector scanning but could when compound scanning was used. Both Technicare and Life Imaging breast ultrasonoscopes produced a greater degree of artifact production and distortion of the textural properties of the phantom than the laboratory instrument. None of these instruments could unequivocally identify any of the microcalcifications, but this may be due to other minute loud echo-producing structures within the phantom.
Meridional and radial scanning of the breast follows the anatomic planes of the breast. The scans at the 90 degrees and 180 degrees axes correspond to the lateral and cephalocaudal x-ray mammograms, respectively. Meridional scanning introduces unique problems of orientation and labeling. The labeling methods suggested in this paper result in comparable portions of each breast lying along identical planes of scan. An equation and a table that define the minimal angular increment required to detect a 0.5-cm lesion at the periphery of the breast are presented. Forms for converting meridional scans to orthogonal localization are also presented. In our hands, this method of labeling has proved to be simpler than that suggested by the American Institute of Ultrasound in Medicine.
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The correct interpretation of echo amplitude patterns of high-resolution gray scale ultrasonograms of the breast requires the use of calibrated color-coded isodensitometry, standardized operation of the ultrasound system, amplitude stability of 1 per cent or better, and a constant velocity water-coupled electro-mechanical scanner. The same conditions may be required for correct interpretation of the ultrasonograms of the parenchyma of the liver, spleen, ovaries, testes, uterus, thyroid, and tumors. Color coding is not required and may actually be detrimental in the study of gross ultrasonography anatomy and in disease states that can be identified by simple anatomical distortions. To be of value, rigid standardization and control of the amplitude characteristics and scanning velocity of the system are imperative.
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Ultrasound mammography was performed with unique, high resolution equipment which displays changes in acoustic properties of tissues through a calibrated gray scale. Color-coded isodensitometry was used to assist in the differential diagnosis. The rate of agreement between the ultrasound and pathological diagnoses was 86.7%. The false negative and false positive rates were 7.6% and 18.5%, respectively. Three problems must be solved before ultrasound mammography can be used as a screening device: First, additional clinical data must be accumulated. Second, the number of ultrasonograms needed for diagnosis must be reduced. Third, special equipment designed for ultrasound mammography must be developed.
Three-dimensional ultrasonograms prepared by superposition optical holography improves anatomical orientation and reduces the volume of data needed to study parenchymal organs such as breast, liver, kidney, spleen, and others. An optical hologram makes it possible to simultaneously view multiple planes of observations and see through and around structures without the superimposition of overlying structures. The use of pulse echo ultrasonograms results in better resolution and gray scale and permits multiplane viewing eliminates the geometric distortions present in acoustical holography.
Several controlled-pore glass (CPG) derivatives were examined as supports for the affinity chromatographic purification of the enzyme beta-galactosidase. The competitive inhibitor p-aminophenyl-beta-D-thiogalactopyranoside was coupled to an azelaic acid and a malonic acid derivative of 750-A alkylamine CPG of 80-120 mesh and to an azelaic acid derivative of 550-A alkylamine CPG of 40-80 mesh. The latter derivative exhibited particularly good load capacity and separation efficiency; however, both arm lengths were effective. Hydrophobic interactions between the arm and the enzyme contribute to the separation.
Three techniques for producing three-dimensional ultrasonograms have been investigated. Of these, the optical holographic technique appears to have the advantages of simultaneous viewing of all levels and directions. The effects of magnification, gray scale manipulation, and more expeditious means of producing such holograms remain to be investigated.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.