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Biomedical subjects

L Beck

Publications and source records attributed to L Beck.

At least 109 records · Page 6Linked to original sources

[Control with progesterone of intracellular sulfate available in glandular epithelial cells of endometrium in culture].

Sulfate incorporation was measured in subcultured glandular epithelial cells from guinea-pig endometrium, treated by estradiol alone or in concert with progesterone. Progesterone significantly increased sulfate incorporation in cellular and secreted macromolecules. However, the greatest effect of progesterone was on the size of the intracellular sulfate pool available for sulfation. This effect of progesterone was correlated with the percentage of cells exhibiting progesterone receptors in vitro.

Animals↗

Interleukin-2 inhibits the interleukin-4-induced human IgE and IgG4 secretion in vivo.

The effect of interleukin-2 (IL-2) on IL-4-induced IgE and IgG4 secretion by B cells in peripheral blood mononuclear cell (PBMC) preparations from non-atopic healthy humans and atopic dermatitis patients was investigated. PBMC were cultured at an optimal concentration of recombinant IL-4 with or without addition of IL-2 for 10 days. Native and recombinant IL-2 inhibited the IL-4-induced IgE and IgG4 secretion in a dose-dependent manner by cells from both normal and atopic donors. Rabbit antibodies to IL-2 or to the monoclonal anti-IL-2 receptor antibody anti-TAC reversed the IL-2 effect. Culturing cells with IL-4 and IL-2 for 1 or 2 days only slightly suppressed the IgE and IgG4 secretion whereas addition of IL-2 to IL-4 containing cultures on day 4 or 5 inhibited the IgE and IgG4 secretion more effectively. This is in contrast to interferon-gamma (IFN-gamma) which inhibited the IL-4 induced IgE and IgG4 secretion when added for the first 24 or 48 h but had no effect when added on days 4 or 5. The data demonstrate that both IL-2 and IFN-gamma act as antagonists in the IL-4-induced IgE and IgG4 secretion by human B cells; while IL-2 appears to inhibit relatively late in culture, IFN-gamma has an early inhibitory effect, suggesting that the two lymphokines inhibit the IL-4 effect by different mechanisms.

B-Lymphocytes↗

Inhibition of isoprenoid biosynthesis and the post-translational modification of pro-p21.

It has recently been reported that a precursor of p21ras (pro-p21ras) becomes modified by a metabolite of mevalonic acid prior to conversion to mature p21ras. We have examined the effect of blocking isoprenoid biosynthesis on this process. Fluoromevalonate, which inhibits the conversion of pyrophosphomevalonate to isopentenyl pyrophosphate, blocks the incorporation of radioactive mevalonate into pro-p21ras, demonstrating the mevalonate must be converted to an isoprenoid prior to such incorporation. Starvation of CHO-K1 cells for mevalonic acid by treatment with mevinolin, an inhibitor of 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase, or mevalonate deprivation in a mevalonate auxotroph defective in HMG-CoA synthase activity results in the accumulation of pro-p21ras. The precursor, accumulated due to either of these treatments, is converted through an intermediate form to the mature p21ras by incubation of cells with mevalonate. Incubation of cells with 25-hydroxycholesterol, the pleiotropic transcriptional down-regulator of cholesterol biosynthesis does not, however, result in the accumulation of pro-p21ras. This result indicates that in contrast to the regulation of cholesterol biosynthesis in mammalian cells, important regulatory control other than at the level of HMG-CoA reductase is involved in the isoprenoid biosynthesis required for protein isoprenylation.

Animals↗

Postpartum pulmonary embolus as an unusual cause of cortical blindness.

A pregnant patient was delivered by cesarean section with blindness occurring in the postoperative period. Diagnostic evaluation revealed the presence of massive pulmonary embolus associated with cardiogenic shock. The differential diagnosis of blindness during pregnancy is discussed.

Adult↗

Diagnosis of premenstrual syndrome by a simple, prospective, and reliable instrument: the calendar of premenstrual experiences.

To establish a quantitative method for the diagnosis of premenstrual syndrome (PMS), a simple prospective inventory, the calendar of premenstrual experiences, was constructed. The validity and reliability of this instrument were assessed by administering it throughout two consecutive ovulatory cycles to 36 rigidly screened women with PMS and to 18 controls. To establish concurrent validity, scores on behavioral items were correlated with simultaneously obtained scores on lengthier, well-validated psychiatric inventories designed to measure depression rather than PMS, the Beck Depression Inventory and the Profile of Mood States. The results showed that the calendar of premenstrual experiences luteal phase score distinguished PMS women from controls correctly in 104 of 108 cycles, with a 2.8% false-negative rate and no false positives when used for two consecutive cycles. An upper limit follicular phase score was observed beneath which all PMS and normal control subjects fell, suggesting that a higher score is not consistent with PMS. Correlation coefficients of calendar item scores with Profile of Mood States scale scores were 0.58 for tension, 0.51 for depression, 0.46 for anger, 0.61 for fatigue, and 0.57 for confusion (P less than .0001 for all correlations). The correlation of the calendar depression item with the Beck Depression Inventory score was 0.56 (P less than .0001). The test-retest reliability of the calendar given in the same phase of two consecutive menstrual cycles was high (r = 0.78, P less than .0001). We conclude that this instrument is a valid, reliable, and practical PMS inventory, applicable to clinical and some research settings.

Adult↗

The polyclonal and antigen-specific IgE and IgG subclass response of mice injected with ovalbumin in alum or complete Freund's adjuvant.

BALB/c mice were injected ip with 1 microgram ovalbumin (OVA) in alum or complete Freund's adjuvant (cFA) and the changes of the IgE and IgG subclass serum levels and isotypes of the anti-OVA specific antibodies determined by radioimmunoassays. By Day 10, OVA in alum had induced a 5- to 10-fold increase of the IgE serum level and an initial decrease of the IgG subclass levels which subsequently increased to two to threefold over the preinjection level. OVA in cFA induced a gradual twofold increase of the IgE serum level, a rapid fourfold increase of the IgG2a level occurring by Day 7, and a gradual two to threefold increase of the other IgG subclasses. Over 90% of the anti-OVA antibodies were of the IgGl isotype with both adjuvants; OVA in alum induced slightly more IgGl anti-OVA antibodies than cFA. In contrast, the OVA in alum injected mice formed significantly more (5- to 10-fold) IgE anti-OVA antibodies than the cFA-injected mice. OVA in alum also induced a large nonspecific increase of the IgE serum level because only approximately 40% of the increase observed on Day 14 was absorbable with OVA, whereas approximately 90% the IgE increase in cFA injected mice was absorbable with OVA. The data demonstrate that mice form mainly IgGl and IgE antibodies to OVA irrespective of the adjuvant. The low specific and lack of nonspecific IgE formation by mice injected with OVA in cFA may be the result of cFA-induced interferon-gamma (IFN-gamma) production because IFN-gamma has been shown to stimulate IgG2a and inhibit IgE secretion in vitro.

Alum Compounds↗