Phenotypic and functional properties of murine thymocytes. III. Kinetic analysis of the recovery of intrathymic cytolytic T lymphocyte precursors after in vivo administration of hydrocortisone acetate

The phenotypic and functional properties of cells in the C57BL/6 mouse thymus regenerating after a single dose of 100 mg/kg hydrocortisone acetate (H/C) are described. Functionally, the frequency of anti-H-2d cytolytic T lymphocyte precursors (CTL-P) in thymuses from individual mice was determined by limit dilution analysis of mixed leukocyte microcultures. The initial increase in CTL-P frequency, seen 48 hr post-H/C, was followed at 6 to 8 days by a phase of rapid decrease. The CTL-P frequency returned to a normal level by 28 days post-H/C. Analysis of the results from individual mice suggested that changes in total thymic CTL-P content were independent of the kinetics of thymus regeneration. Phenotypically, whereas the thymus 48 hr after H/C was considerably depleted of Lyt-2+ cells, there followed a rapid increase in the proportion of such cells to normal levels by 14 days post-H/C. In addition, as measured by FLS, a subpopulation of larger, predominantly Lyt-2+ cells was found during the phase of rapid thymic regeneration. With the use of a monoclonal anti-Thy-1.2 antibody, the weakly Thy-1-staining subpopulation of cells was absent from the thymus at 14 days post-H/C. These changes in the phenotypic properties of the post-H/C regenerating thymus were correlated with changes in their functional properties.     

Ultrastructural changes in nurse and follicle cells during late stages of oogenesis in Drosophila melanogaster

Summary During stages 11 and 12, follicle cells surrounding the nurse cells produce lysosomes which presumably aid in the breakdown of the nurse cells. Accompanying a DNA reduction in nurse cell nuclei are several characteristic morphological changes including the appearance of intranuclear rod-like structures and nuclear granules about 300 Å in diameter. Similarities between structures seen in Drosophila nurse cell nuclei and those seen in other organisms are discussed.This research was supported by U. S. Public Health Service Grants 5TIGM903-3 and 1-F1-GM-33, 385-01 and National Science Foundation grant GB-7457.     

On surface geometry coupled to morphogen

An expression is derived for both the Gauss and the Mean curvature of a surface, in terms of three simple cell parameters. The surface is thought of as composed of a single-cell thick sheet of cells joined laterally. The three cellular parameters involved are the ratios of (linear) basal to apical dimension in two orthogonal directions, S1 and S2, and the cell thickness "h". These three parameters may be envisioned as functions of a morphogen or morphogens which vary from point to point over the (middle) surface. As an example, the "reaction-diffusion" equations which are often used to describe pattern-formation in early development can be seen as possible candidates for these morphogens, when the resultant surface deformations are given when the dependence of the three cellular parameters are specified as a function of morphogen concentration. The coupling back of the surface deformations to the set of reaction-diffusion equations is simply given, and is through the dependence on geometry of the Laplacian operator which enters these equations.     

Growth of Phytomonas serpens in a Defined Medium; Nutritional Requirements

ABSTRACT. Three strains of Phytomonas serpens two from tomatoes, Lycopersicon esculentum one from the insect Phtia picta (Hemiptera, Coreidae), were cultivated in a chemically defined medium developed from a defined medium for cultivating insect flagellates. Besides organic growth factors required by other insect trypanosomatids this flagellate requires, serine and inositol. Glutamine stimulates growth, and, surprisingly, does not require heme.     

Lung overexpansion increases pulmonary microvascular protein permeability in young lambs

To study the effects of inflation pressure and tidal volume (VT) on protein permeability in the neonatal pulmonary microcirculation, we measured lung vascular pressures, blood flow, lymph flow (QL), and concentrations of protein in lymph (L) and plasma (P) of 22 chronically catheterized lambs that received mechanical ventilation at various peak inflation pressures (PIP) and VT. Nine lambs were ventilated initially with a PIP of 19 +/- 1 cmH2O and a VT of 10 +/- 1 ml/kg for 2-4 h (base line), after which we overexpanded their lungs with a PIP of 58 +/- 3 cmH2O and a VT of 48 +/- 4 ml/kg for 4-8 h. QL increased from 2.1 +/- 0.4 to 13.9 +/- 5.0 ml/h. L/P did not change, but the ratio of albumin to globulin in lymph relative to the same ratio in plasma decreased, indicating altered protein sieving in the pulmonary microcirculation. Seven other lambs were mechanically ventilated for 2-4 h at a PIP of 34 +/- 1 cmH2O and a VT of 23 +/- 2 ml/kg (base line), after which their chest and abdomen were bound so that PIP increased to 54 +/- 1 cmH2O for 4-6 h without a change in VT. QL decreased on average from 2.8 +/- 0.6 to 1.9 +/- 0.3 ml/h (P = 0.08), and L/P was unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)     

Differential Expression of a Mycobacterium tuberculosis Protein Recognized by a Mouse Monoclonal Antibody

Murine monoclonal antibodies were produced against Mycobacterium tuberculosis (Mtb) using standard hybridoma procedures. By a whole cell enzyme-linked immunosorbent assay (ELISA), one monoclonal antibody (mAb), HB28, demonstrated high level specific reactivity to Mtb. Western blot analysis demonstrated reactivity to a single 65 kDa Mtb protein in the cell wall extract and culture filtrate. HB28 mAb appears to be recognizing a 65 kDa Mtb protein that is over-expressed by Mtb but not other species under certain culture conditions. Differential expression and detection of this protein by HB28 mAb may have potential for diagnostic applications.     

Membrane Skeletal Proteins and Their Integral Membrane Protein Anchors are Targets for Tyrosine and Threonine Kinases in Euglena

ABSTRACT. Proteins of the membrane skeleton of Euglena gracilis were extensively phosphorylated in vivo and in vitro after incubation with [³²P]-orthophosphate or γ-[³²P] ATP. Endogenous protein threonine/serine activity phosphorylated the major membrane skeletal proteins (articulins) and the putative integral membrane protein (IP39) anchor for articulins. The latter was also the major target for endogenous protein tyrosine kinase activity. A cytoplasmic domain of IP39 was specifically phosphorylated, and removal of this domain with papain eliminated the radiolabeled phosphoamino acids and eliminated or radically shifted the PI of the multiple isoforms of IP39. In gel kinase assays IP39 autophosphorylated and a 25 kDa protein which does not autophosphorylate was identified as a threonine/serine (casein) kinase. Plasma membranes from the membrane skeletal protein complex contained threonine/serine (casein) kinase activity, and cross-linking experiments suggested that IP39 was the likely source for this membrane activity. pH optima, cation requirements and heparin sensitivity of the detergent solubilized membrane activity were determined. Together these results suggest that protein kinases may be important modulators of protein assembly and function of the membrane skeleton of these protistan cells.     

Risk of breast cancer in relation to the interval since last full term pregnancy.

OBJECTIVE--To examine whether the risk of breast cancer is increased by a recent term pregnancy. DESIGN--Population based case-control study. SETTING--Eight areas in the United States. SUBJECTS--Cases were 2279 multiparous women residents of the eight areas aged 25-49 who were diagnosed as having breast cancer during 1980-2. Controls were 2357 multiparous women selected from the same areas by random digit dialing. MAIN OUTCOME MEASURE--Relative risk of developing breast cancer according to the time interval since last full term pregnancy. RESULTS--The distribution of intervals since the last term pregnancy was similar in cases and controls. Adjusted for age, parity, and age at first term pregnancy, the odds ratios observed for categories of years since the last full term pregnancy were: 0-2 years, odds ratio 1.16 (95% confidence interval 0.84 to 1.59); 3-6 years, odds ratio 1.21 (0.95 to 1.54); 7-9 years, odds ratio 1.04 (0.84 to 1.38); > or = 10 years, odds ratio 1.00 (reference). CONCLUSIONS--Among multiparous women aged 25-49 years there was no association between the risk of breast cancer and the time interval since the last full term pregnancy.