Effects of spaceflight on rat pituitary cell function

The secretory capacity of growth hormone (GH) and prolactin (PRL) cells prepared from rats flown in space on the 12.5-day mission of COSMOS 1887 and the 14-day mission of COSMOS 2044 was evaluated in several postflight tests on Earth. The results showed statistically significant and repeatable decrements in hormone release, especially when biologic (rather than immunologic) assays were used in the tests. Significant and repeatable intracellular changes in GH cells from the flight animals were also found; most important were increases in the GH-specific cytoplasmic staining intensities and cytoplasmic areas occupied by hormone. Tail suspension of rats for 14 days, an established model for mimicking musculoskeletal changes in rats flown in space, resulted in some changes in GH and PRL cell function that were similar to those from animals flown in space. Our results add to a growing body of data that describe deconditioning of physiological systems in spaceflight and provide insights into the time frame that might be required for readaptation of the GH/PRL cell system on return to Earth.

Diagnostic evaluation of ascitic adenosine deaminase activity in tubercular peritonitis

Activity of adenosine deaminase (ADA) in serum and peritoneal fluid was studied prospectively in 24 aetiologically proved cases of ascites and 10 age-matched controls. Patients were divided into 3 groups according to causes of ascites, viz. malignant ascites (11), tubercular peritonitis (7) and cirrhosis of liver (6). Serum ADA values and peritoneal: serum ADA ratio did not show any consistent pattern in any group. But in patients with tubercular peritonitis ADA activity in ascitic fluid was significantly higher (P < .001) than in the other groups. An ascitic ADA level of 30 units/L had a sensitivity of 100% and specificity of 94.1% for tubercular peritonitis. These findings suggest that the ascitic fluid ADA activity is useful for the diagnosis of tubercular peritonitis; this method is simple and least invasive.

Interaction of T-DNA border sequences and Ti-plasmid vir functions of Agrobacterium results in differential single-stranded linear T-DNA molecule production and plant transformation

The mechanism of Agrobacterium mediated genetic transformation of plants is dependent upon certain genetic function of the chromosome of the bacterium as well as on Ti-plasmid borne vir loci and the border sequences of T-DNA. The organisationally variable forms of the naturally occurring border sequences amongst Ti-plasmid types are differentially responsive to gene products of vir loci concerned with T-strand production. Additionally, the production of stable transformants is dependent upon vir gene products effective after T strands are produced. The interaction of border sequences from different strains of Agrobacterium with vir proteins encoded by various helper plasmids revealed that functional differences do exist amongst vir gene products contained in the type of helper plasmids used.

Prolactin-induced mitogenesis of lymphocytes from ovariectomized rats

PRL can induce interleukin-2 (IL-2) receptor expression in splenocytes from ovariectomized (OVX) female rats. In this further study of the effects of PRL on lymphocytes in vitro we found that PRL induced IL-2 receptor expression, IL-2 production, and proliferation of splenocytes and thymocytes from OVX rats. Cells from male rats were not affected. The proliferative response, as measured by [3H]thymidine incorporation, depended on the concentration of PRL and the presence of adherent cells in the culture. After a 48-h incubation with PRL (1 microgram/ml), splenocytes from OVX rats incorporated essentially the same amount of [3H]thymidine as cells incubated with the polyclonal T-cell mitogen Concanavalin-A (ConA). As determined by autoradiography, approximately 40% of the splenocytes responded to PRL or to ConA. After incubation of splenocytes and thymocytes with PRL, bioactive IL-2 was detected in culture medium only from cells of OVX female rats, while incubation with ConA caused IL-2 production by lymphocytes from both male and OVX rats. However, ConA induced IL-2 activity sooner than PRL. Immunofluorescent-flow cytometric analysis revealed time-dependent increases in percentages of IL-2 receptor-positive splenocytes as well as increases in percentages of total T-cells and cells of the CD8 and, to a lesser extent, the CD4 subclass after PRL stimulation.

Some prospective observations on recent outbreak of typhoid fever in West Bengal

The present study was designed to study the clinical behaviour of a recent epidemic of typhoid fever in West Bengal. Of 46 cases studied, 67% (31) had chloramphenicol resistant typhoid fever. The chloramphenicol-resistant cases were comparatively severe in nature with higher complication and mortality rates. Salmonella typhi resistant to chloramphenicol were also resistant to ampicillin, cloxaxillin and cotrimoxazole. Strains of Salmonella typhi sensitive to chloramphenicol retained their sensitivity to these other antimicrobials.

Function of prolactin cells in the individual rat pituitary gland is location dependent

Anterior pituitary glands from individual ovariectomized (ovx) or ovx-estrogen (E2) treated rats were sectioned into 1/8 cubes. Each section was incubated for four consecutive 15 min periods in order to measure the release of immunoreactive and bioactive prolactin (PRL); each individual section was then trypsinized into a single cell suspension for determination of PRL cell numbers in that section. Hormone release (ng PRL/1000 PRL cells) was not uniform throughout the gland; the consistency of the secretory patterns demonstrated that the amount of PRL release from the gland was location-dependent. Statistical analysis of the data showed that the most active cells were in the gland's left lobe, while the least active were in the right lobe. Within these lobes, the dorsal-caudal and ventral-rostral left lobe areas released the most hormone in vitro while those in the dorsal-rostral, dorsal-caudal and ventral-rostral right lobe areas were least active. Injection of ovx rats with E2 for 2 days altered these secretory patterns. This sectioning procedure should prove useful in future studies addressing issues of cell-cell interaction and geographic location as they relate to pituitary cell function.

Short term effect of diltiazem on portal hypertension in patients with non-cirrhotic portal fibrosis

Fourteen patients of non-cirrhotic portal fibrosis (NCPF) with portal hypertension were put on oral diltiazem hydrochloride (90 mg/day) or placebo on a prospective, randomised, single blind basis for 15 days. Predrug hemodynamic and biochemical status were similar in both groups. Diltiazem produced significant reduction (p less than 0.001) in mean intrasplenic pressure: from 41.88 (SD +/- 6.18) to 21.5 (+/- 7.91) cm of normal saline as against 45.56 (+/- 9.45) to 43.33 (+/- 8.27) in the placebo group. Mean arterial pressure (MAP), heart rate and cardiac output (CO) did not change in either group. Thus, the calcium channel blocker diltiazem reduces portal pressure in patients with NCPF, independent of reduction in MAP and CO; this is advantageous in situations where compromised cardiac hemodynamics may prove deleterious.

Antiproliferative action of retinoic acid in cultured human brain tumour cells Gl-As-14(S)

We have employed human Gl-As-14(S) brain tumour cell line to study antiproliferative action of retinoic acid (RA). RA (20 microM) caused a time-dependent, dose-dependent, cell seeding density-dependent reduction in cell proliferation in liquid medium and inhibited growth in agar. Growth inhibitory effects of RA were also affected by the concentration of fetal bovine serum (PBS) in the medium. All these effects could be reversed within 48 h after removal of RA from the growth medium. RA-treated cells also displayed reduced concanavalin A (Con A) binding ability by microhemadsorption technique. The results demonstrated that RA can suppress in this tumour cell line the expression of some properties frequently associated with transformed cells.

Prolactin induction of interleukin-2 receptors on rat splenic lymphocytes

A case for the involvement of PRL in the regulation of the immune system is strong. However, no mechanism by which PRL exerts this regulation has yet been identified. We studied the in vitro effects of PRL on splenocytes from ovariectomized (OVX) rats and discovered that PRL induced the formation of interleukin-2 (IL-2) cell surface receptors. However, PRL did not induce IL-2 secretion. This response, which was dependent on the concentration of PRL, also depended upon the estrogen status of the splenocyte donor; thus, splenocytes from OVX rats or rats in diestrus responded to PRL, whereas those from estrogen-treated OVX rats or rats in estrus did not. We propose that in vivo exposure of PRL, under certain physiological conditions, may prime a pool of splenocytes to express IL-2 cell surface receptors, allowing these cells to be responsive to variations in local concentrations of IL-2.

Spontaneous neoplastic evolution of Swiss mouse embryo cells (PMS-14) in culture

Some biological properties related to transformation have been studied to characterize a spontaneously transformed mouse embryonic fibroblast cell line, PMS-14. Low population doubling time with moderately high plating efficiency and saturation density were noted. These cells showed reduced adhesion to substratum, enhanced agglutinability by concanavalin A, anchorage independent growth in soft agar and tumorigenicity in mice.

Biological and growth properties of a 20-methyl-cholanthrene transformed murine fibroblast cell line (PMM-14) established from primary culture

Some major transformation related biological and growth properties have been analysed in an in vitro, system to characterize the PMM-14 cell line, a 20-methylcholanthrene induced transformed mouse embryonic fibroblast cell line. The population doubling time of this cell line was 19 h with moderately high saturation density and plating efficiency. Attachment detachment properties showed reduced adhesion to substratum. Cytogenetic study revealed the existence of a large number of Robertsonian biarmed chromosomes with hypertriploid modal range (60-69) represented by about 21% cells. These cells showed enhanced concanavalin A agglutinability which was reduced by trypsin treatment. Its neoplastic nature was finally established by its ability to grow in agar with a high plating efficiency.

Aggregation and fusion of unilamellar vesicles by poly(ethylene glycol)

Various aspects of the interaction between the fusogen, poly(ethylene glycol) and phospholipids were examined. The aggregation and fusion of small unilamellar vesicles of egg phosphatidylcholine (PC), bovine brain phosphatidylserine (PS) and dimyristoylphosphatidylcholine (DMPC) were studied by dynamic light scattering, electron microscopy and NMR. The fusion efficiency of Dextran, glycerol, sucrose and poly(ethylene glycol) of different molecular weights were compared. Lower molecular weight poly(ethylene glycol) are less efficient with respect to both aggregation and fusion. The purity of poly(ethylene glycol) does not affect its fusion efficiency. Dehydrating agents, such as Dextran, glycerol and sucrose, do not induce fusion. 31P-NMR results revealed a restriction in the phospholipid motion by poly(ethylene glycol) greater than that by glycerol and Dextran of similar viscosity and dehydrating capacity. This may be associated with the binding of poly(ethylene glycol) to egg PC, with a binding capacity of 1 mol of poly(ethylene glycol) to 12 mol of lipid. Fusion is greatly enhanced below the phase transition for DMPC, with extensive fusion occurring below 6% poly(ethylene glycol). Fusion of PS small unilamellar vesicles depends critically on the presence of cations. Large unilamellar vesicles were found to fuse less readily than small unilamellar vesicles. The results suggest that defects in the bilayer plays an important role in membrane fusion, and the 'rigidization' of the phospholipid molecules facilitates fusion possibly through the creation of defects along domain boundaries. Vesicle aggregation caused by dehydration and surface charge neutralization is a necessary but not a sufficient condition for fusion.

Studies on the recovery of heated bacteria

The influence of ultraviolet (uv.) irradiation on the recovery from heat-induced damage was studied. It was observed that the recovery phenomenon remained unaffected by ultraviolet treatment. The cells subjected to heat treatment at 52 °C were also allowed to recover under the influence of bacterial extract. No recovery of heat damage with extract was found observable under conditions used here.