Cellular signals underlying ß-adrenergic receptor mediated salivary gland enlargement.

We examined the cellular signaling pathways involved in parotid gland enlargement induced by repeated isoproterenol administration in rats. Immunoblot analysis revealed early (1h) activation of the mitogen activated protein kinase (MAPK) ERK1/2, and progressive activation of epidermal growth factor receptor (EGFR), p38MAPK and p70S6 kinase (p70S6K) during 72h of isoproterenol treatment. Expression of ß-adrenergic receptors (ARs) of the ß2, but not ß1, subtype increased over time in parallel with increases in the proliferation marker PCNA and parotid gland weight. Levels of ß2-AR mRNA, assessed by quantitative RT-PCR and Northern blot analysis, were upregulated in parotid glands of isoproterenol treated rats. cAMP response element binding protein (CREB), a positive regulator of ß2-AR transcription, was activated at 1h after isoproterenol administration, as evidenced by increased nuclear translocation and DNA binding using immunohistochemical staining and electrophoretic mobility shift assay. ELISA of NF-κB, also a ß2-AR transcriptional regulator, revealed an increase in p65 and p50 subunits in nuclear protein extracts from parotid glands of isoproterenol treated rats. Together, these results demonstrate that ß-adrenergic stimulation activates diverse cell survival and progrowth signaling pathways, including cAMP and EGFR linked activation of ERK1/2, p38MAPK, and p70S6K, and also induction of ß2-ARs, possibly mediated by CREB and NF-κB, resulting in salivary gland enlargement. We propose that during isoproterenol treatment activation of the ß1-AR, the predominant ß-AR subtype in unstimulated salivary glands, initiates proliferative signaling cascades, and that upregulation of the ß2-AR plays an essential role in later stages of salivary gland growth.

Safe and Ethical Artificial Intelligence in Radiotherapy - Lessons Learned From the Aviation Industry.

Ethical artificial intelligence (AI) frameworks can be the catalyst in improving the safety and wellbeing of people when developing AI systems. In 2020 Rolls-Royce released its ethical and trustworthiness toolkit, The Aletheia FrameworkTM, which helps guide organisations as they consider the ethics around the use of AI. It covers three facets: social impact, accuracy and trust, and governance - which apply across all uses of AI. By adopting AI ethics and trust frameworks, oncologists can ensure the ratio between the benefit and harms of AI can be maximised. With AI transforming every sector, collaboration across industries to share ideas and learn from each other - even unlikely partnerships between engineering and oncology - could help optimise that transition.

The primary stability of two dental implant systems in low-density bone.

Primary stability in low-density bone is crucial for the long-term success of implants. Tapered implants have shown particularly favourable properties under such conditions. The aim of this study was to compare the primary stability of tapered titanium and novel cylindrical zirconia dental implant systems in low-density bone. Fifty implants (25 tapered, 25 cylindrical) were placed in the anterior maxillary bone of cadavers meeting the criteria of low-density bone. The maximum insertion (ITV) and removal (RTV) torque values were recorded, and the implant stability quotients (ISQ) determined. To establish the isolated influence of cancellous bone on primary stability, the implantation procedure was performed in standardized low-density polyurethane foam bone blocks (cancellous bone model) using the same procedure. The primary stability parameters of both implant types showed significant positive correlations with bone density (Hounsfield units) and cortical thickness. In the cadaver, the cylindrical zirconia implants showed a significantly higher mean ISQ when compared to the tapered titanium implants (50.58 vs 37.26; P < 0.001). Pearson analysis showed significant positive correlations between ITV and ISQ (P = 0.016) and between RTV and ISQ (P = 0.035) for the cylindrical zirconia implants; no such correlations were observed for the tapered titanium implants. Within the limitations of this study, the results indicate that cylindrical zirconia implants represent a comparable viable treatment option to tapered titanium implants in terms of primary implant stability in low-density human bone.

Independently derived murine glomerular immune deposit-forming anti-DNA antibodies are encoded by near-identical VH gene sequences.

To examine the influence of variable region sequences on the capacity of individual lupus autoantibodies (autoAb) to form glomerular immune deposits, the complete VH and VL region sequences of three anti-DNA mAb that produced morphologically similar immune deposits after administration to normal mice were determined. The Ig were independently derived from 1-mo-old (H238, IgM), 3-mo-old (H8, IgG2a), and 6-mo-old (H161, IgG3) MRL-lpr/lpr mice, and they all produced subendothelial and mesangial immune deposits after passive transfer to normal mice. In addition, H238 and H161 produced granular deposits in small extraglomerular vessels. The mAb had nearly identical VH gene sequences; H8 differed from H238 and H161 by a single nucleotide in FR1 that resulted in a histidine for glutamine substitution. This VH gene sequence was also > 99% homologous to another anti-DNA Ab (termed H241), that we previously reported to produce glomerular immune deposits in a similar morphologic pattern. H161 and H238 were encoded by DFL16 and JH2 genes, whereas H8 was encoded by a JH4 gene. Different Vk family genes were used to encode the three mAb, however H161 and H238 both used a Jk5 gene. The results indicate that an identical or highly related VH gene is used to encode a subgroup of murine lupus autoAb that share immune deposit forming properties. Furthermore, they raise the possibility that amino acid residues independent from those encoded by VH genes may be influential in immune deposit formation at extraglomerular sites.

Effects of a synthetic peptide of a parathyroid hormone-related protein on calcium homeostasis, renal tubular calcium reabsorption, and bone metabolism in vivo and in vitro in rodents.

A synthetic peptide corresponding to the first 34 amino acids of the parathyroid hormone-related protein (PTH-rP) produced by a human tumor associated with hypercalcemia was examined for skeletal and renal effects on calcium metabolism in vivo and in vitro. These effects were compared with those of human parathyroid hormone (1-34), hPTH (1-34). Equal doses of PTH-rP(1-34) and hPTH(1-34) produced equivalent stimulation of adenylate cyclase in vitro in bone cells and kidney cells and tubules. Subcutaneous injection of PTH-rP(1-34) in mice caused a significant dose-related increase in blood ionized calcium similar to that seen with hPTH(1-34) at equivalent doses. Repeated injections of equal doses of both peptides caused sustained hypercalcemia which was significantly greater in PTH-rP(1-34)-treated mice, although each induced comparable increases in histomorphometric indices of osteoclastic bone resorption. PTH-rP(1-34) and hPTH(1-34) also caused similar increases in bone resorption when incubated with fetal rat long bones in organ culture. Infusion of either peptide into thyroparathyroidectomized rats suppressed urinary calcium excretion and increased urinary excretion of cyclic AMP. PTH-rP appears to have similar effects to those of PTH on the skeleton, the kidney, and overall calcium homeostasis.

Outcome with lenalidomide plus dexamethasone followed by early autologous stem cell transplantation in patients with newly diagnosed multiple myeloma on the ECOG-ACRIN E4A03 randomized clinical trial: long-term follow-up.

In Eastern Cooperative Oncology Group-ACRIN E4A03, on completion of four cycles of therapy, newly diagnosed multiple myeloma patients had the option of proceeding to autologous peripheral blood stem cell transplant (ASCT) or continuing on their assigned therapy lenalidomide plus low-dose dexamethasone (Ld) or lenalidomide plus high-dose dexamethasone (LD). This landmark analysis compared the outcome of 431 patients surviving their first four cycles of therapy pursuing early ASCT to those continuing on their assigned therapy. Survival distributions were estimated using the Kaplan-Meier method and compared with log-rank test. Ninety patients (21%) opted for early ASCT. The 1-, 2-, 3-, 4- and 5-year survival probability estimates were higher for early ASCT versus no early ASCT at 99, 93, 91, 85 and 80% versus 94, 84, 75, 65 and 57%, respectively. The median overall survival (OS) in the early versus no early ASCT group was not reached (NR) versus 5.78 years. In patients <65 years of age, median OS in the early versus no early ASCT groups was NR in both, hazard ratio 0.79, 95% confidence interval: (0.50, 0.25). In patients ⩾65 years of age, median OS in the early versus no early ASCT was NR versus 5.11 years. ASCT dropped out of statistical significance (P=0.080). Patients opting for ASCT after induction Ld/LD had a higher survival probability and improvement in OS regardless of dexamethasone dose density.

Anions and cations as stimulators of liver adenylate cyclase.

The effects of inorganic salts on adenylate cyclase activities were studied in rat liver homogenates, particulates, and purified membranes. Na+ salts of N-3, NO-2, S2O32-, SO42-, and non-F- halides stimulated homogenates by a maximum of 2---5-fold; half-maximal effects were seen at concentrations ranging from 90 mM (Na2S2O3) to 410 mM (NaNo2). NaIO3 stimulated about 2-fold at relatively low salt concentrations (5---20 mM). Na+ salts were stimulatory using both ATP and the ATP analog 5'-adenylyl-beta, gamma-imidodiphosphate (AMP-P(NH)P) as enzyme substrate. The time courses of stimulation by NaCl and NaN3 were linear to at least 10 min with any of the three tissue preparations. Although salt effects clearly varied with the different anions, the magnitude and dose-response of stimulation of homogenates by Cl- salts were also dependent on the accompanying alkali cation (Li+, Na+, K+, Rb+, Cs+). MgCl2 at relatively high concentrations (50 mM) enhanced NaCl-stimulated activity in homogenates only slightly at relatively low concentrations of NaCl and not at high concentrations, suggesting a common mechanism of activation by Mg2+ and Na+ salts. NaCl- and NaN3-stimulated activities were unstable in homogenates kept at 0 degree C for 4 h, falling to 35% and 50% of their respective baseline activities. The effects on homogenates and particulates of maximally stimulatory concentrations of NaCl and NaN3 were further enhanced by GTP and the GTP analog 5'-guanylyl-beta, gama-imidodiphosphate (GMP-P(NH)P).

Quantitation of epinephrine- and glucagon-sensitive adenylate cyclases of rat liver. Implications of alterations of enzymatic activities during preparation of particulate fractions and membranes.

Stimulated and basal adenylate cyclase activities from livers of young and old rats were lower in particulates than in homogenates. Particulates were compared to homogenates by reconstituting the suspensions to the volume of the homogenates from which they were derived; enzyme activities in paired homogenates and particulates therefore reflected the same amounts of membrane-bound enzyme. The magnitude of the losses of hormone-sensitive activities in particulates was dependent on the age and sex of the animals and the concentrations of hormone. Particulates from 3-month-old animals showed glucagon-(1 . 10(-5) M) and epinephrine-sensitive (1 . 10(-4) M) activities which were 67 and 78% of homogenate activities, respectively; particulates from 24-month-old animals had activities relative to homogenates of 55% for glucagon and as low as 32% for epinephrine. The glucagon dose vs. response curve in particulates and membranes showed maximal activity at 1 . 10(-7) M glucagon while in homogenates activity increased linearly with increasing glucagon concentrations up to 1 . 10(-5) M. Losses of basal and anion-stimulated activities were similar at both ages. Fluoride and azide stimulations relative to basal activities were greater in particulates than in homogenates, while relative epinephrine activity was lower in particulates, suggesting qualitative alteration of adenylate cyclase during preparation of particulates. These studies show that adenylate cyclase activity in rat liver is presently best quantitated in homogenates and suggest caution in comparisons of enzyme activities based on particulates or membranes prepared from animals of differing physiologic states.

G-protein signaling abnormalities mediated by CD95 in salivary epithelial cells.

Salivary epithelial cells from patients with primary Sjögren's syndrome (SS) undergo Fas-mediated apoptosis. Bcl-2 and Bcl-xL are apoptosis suppressing oncogenes. Very little is known about the role of these oncogene molecules in salivary epithelial cells. To investigate the possible prevention of salivary glandular destruction in SS by Bcl-2 and Bcl-xL, stable transfectants expressing these molecules were made from HSY cells, a human salivary epithelial cell line. HSY cells were transfected with an expression vector for human Bcl-2 or Bcl-xL. Stable transfectants were selected and apoptosis was induced by anti-Fas antibody. Apoptosis was quantified by propidium iodide staining followed by flow cytometry. Caspase activity was detected by immunohistochemical analysis and enzyme cleavage of DEVD-AMC, a fluorescent substrate. Response to carbachol, a muscarinic receptor agonist, and EGF was measured by Ca2+ mobilization and influx. Fas-mediated apoptosis was significantly inhibited in Bcl-2 and Bcl-xL transfectants compared to wild-type and control transfectants (empty vector). Surprisingly, caspase activity was not inhibited in Bcl-2 and Bcl-xL transfectants. Activation of the Fas pathway in the Bcl-2 and Bcl-xL transfectants by antibody also inhibited carbachol and EGF responsiveness (i.e., Ca2+ mobilization and/or influx) by 50-60%. This Fas-mediated inhibition of cell activation was partially or completely restored by specific peptide interference of caspase enzyme activity. The prevention of Fas-mediated apoptosis by the overexpression of Bcl-2 and Bcl-xL in salivary gland epithelial cells results in injured cells expressing caspase activity and unable to respond normally to receptor agonists. Such damaged cells may exist in SS patients and could explain the severe dryness out of proportion to the actual number of apoptotic cells seen on salivary gland biopsy.

Alterations in hormone-sensitive adenylate cyclase of cloned rat osteosarcoma cells during long-term culture.

The hormone-sensitive adenylate cyclase system of a cloned bone cell line (UMR-106) derived from a rat osteosarcoma was compared in preparations from cells of early passages (less than 50) and cells maintained in continuous culture for over two years (late passages). Late passage cells showed greater calcitonin (CT)-stimulated adenylate cyclase activity than did early passages, whereas stimulation by PTH and the beta-adrenergic agonist isoproterenol decreased in late passages. Hormone concentrations giving half-maximal stimulation were the same in early and late passages. Stimulation by agents (GTP and fluoride) which act at the stimulatory guanine nucleotide regulatory component (Ns) of adenylate cyclase was equivalent in early and late passages. Forskolin stimulation, which assessed catalytic component (and possibly Ns) activity, was reduced in late passages. These results are consistent with acquisition by cultured UMR-106 cells of CT receptors linked to adenylate cyclase and loss of PTH and beta-adrenergic receptors. Alteration of catalytic component (and/or Ns) function may also occur after long-term culture. Since late passage cells appear dedifferentiated by chromosomal analysis and since cAMP may regulate differentiation, altered hormone-sensitive adenylate cyclase may be a marker for and a potential modulator of differentiation occurring in UMR-106 cells over long periods.

Adenylate cyclase of osteoblast-like cells from rat osteosarcoma is stimulated by calcitonin as well as parathyroid hormone.

Isolated bone cells are often described according to the presence of PTH- and calcitonin (CT)-sensitive adenylate cyclase activities. Osteoblasts are thought to be cells with PTH-sensitive adenylate cyclase but without CT response, and osteoclasts are thought to be CT-sensitive cells. We have studied the adenylate cyclase of a cloned bone cell line (UMR-106) derived from a rat osteosarcoma and used as a model of osteoblastic cells. Cells maintained in continuous culture for over 2 yr contain adenylate cyclase responsive to CT as well as PTH. The stimulatory effects of both hormones are dependent on hormone concentration, time, and the guanine nucleotide GTP. PTH and CT may activate the same adenylate cyclase in UMR-106 cells, since the stimulatory effects of the two hormones are not additive when combined at concentrations giving maximal activity. The beta-adrenergic agonist isoproterenol also stimulates adenylate cyclase in these cells. Unlike late passages of UMR-106 cells, cells of earlier passages (less than 50) showed only slight CT-sensitive adenylate cyclase activity. Our results suggest that studies of hormone effects attributed to the osteoblast phenotype should consider possible alteration of hormone responsiveness in cloned tumor cells during long term culture.

Relationship of sex hormones to lipids and lipoproteins in nondiabetic men.

Although many studies show that increased androgenicity is associated with increased triglyceride (TG) and decreased high density lipoprotein cholesterol in both pre- and postmenopausal women, relatively few data are available on the association of sex hormones to lipids and lipoproteins in men. We examined the association of sex hormone-binding globulin (SHBG), total and free testosterone, dehydroepiandrosterone sulfate (DHEA-SO4), and estradiol with lipids and lipoproteins in 178 nondiabetic men from the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. The TG concentration was significantly inversely related to SHBG (r = -0.22), free testosterone (r = -0.15), total testosterone (r = -0.22), and DHEA-SO4 (r = -0.16). High density lipoprotein (HDL) cholesterol was significantly positively correlated to SHBG (r = 0.21), free testosterone (r = 0.15), total testosterone (r = 0.17), and DHEA-SO4 (r = 0.16). Total testosterone was significantly related to total cholesterol (r = -0.17) and low density lipoprotein cholesterol (r = -0.15). After adjustment for age, body mass index, waist to hip ratio, and glucose and insulin concentrations, TG concentrations remained significantly related to SHBG (r = -0.20), free testosterone (r = -0.15), and DHEA-SO4 (r = -0.18), and HDL cholesterol remained significantly associated with SHBG (r = 0.17), free testosterone (r = 0.15), total testosterone (r = 0.14), and DHEA-SO4 (r = 0.16). In conclusion, we observed a less atherogenic lipid and lipoprotein profile with increased testosterone concentrations. This was not explained by differences in glucose or insulin concentrations. However, sex hormones explained only a small percentage of the variation in total TG and HDL cholesterol concentrations. These findings are in striking contrast to data from women, in whom increased androgenicity is strongly associated with increased TG and decreased HDL cholesterol levels.

Ectopic beta-adrenergic receptors coupled to adenylate cyclase in human adrenocortical carcinomas.

The adenylate cyclase of an adrenocortical carcinoma of the rat is activated not only by ACTH but also by beta-adrenergic agonists, which bind to ectopic beta-adrenergic receptors not present in normal rat adrenal cortex. Previous reports examining possible beta-adrenergic control of adenylate cyclase in human adrenocortical carcinomas failed to demonstrate beta-adrenergic receptor-linked enzyme activity. We studied six human adrenal carcinomas and normal adrenal cortex from three subjects for beta-adrenergic agonist-sensitive adenylate cyclase and beta-adrenergic binding sites. Three of the six carcinomas had adenylate cyclase responses to both ACTH and beta-agonists. Two tumors were ACTH responsive but not beta-agonist responsive; one tumor responded to beta-agonists but not to ACTH. Adenylate cyclase activity of normal adrenal cortex from three subjects was stimulated by ACTH but not by beta-agonists. In membrane preparations from three tumors with beta-agonist-sensitive adenylate cyclase, the radiolabeled beta-adrenergic antagonist [125I]pindolol bound specifically and with high affinity (Kd = 38-83 pM) to a single class of binding sites which showed saturation with ligand concentration, reversibility of binding, pharmacological specificity, and stereospecificity. Normal cortex and one tumor without beta-adrenergic agonist-sensitive adenylate cyclase had no specific binding of [125I]pindolol. These results indicate that malignant transformation of adrenal cortex in man is frequently but not invariably associated with the appearance of ectopic beta-adrenergic receptors functionally linked to adenylate cyclase. Loss of ACTH-responsive adenylate cyclase may also occur simultaneously with the development of beta-adrenergic receptor-linked adenylate cyclase.

Toxoplasmosis presenting as panhypopituitarism in a patient with the acquired immune deficiency syndrome.

A 57-year-old man with a prior episode of lymphatic toxoplasmosis presented with signs of anterior panhypopituitarism, which was confirmed by standard endocrinologic evaluation. The diagnosis of central nervous system toxoplasmosis was established by brain biopsy after nondiagnostic serologic and radiographic studies. At autopsy, the anterior pituitary was necrotic, with Toxoplasma abscesses in neighboring brain structures. Clinical and laboratory data met the criteria for the acquired immune deficiency syndrome. Although this is the first reported case of toxoplasmosis presenting as panhypopituitarism, future cases may be identified since central nervous system toxoplasmosis is being recognized more frequently in patients with immunodeficiency.

Beta adrenergic regulation of rat liver glycogenolysis during aging.

Studies from a number of laboratories demonstrate a biphasic change in beta adrenergic regulation of hepatic glycogenolysis over the life span of the male rat. The beta adrenergic response is prominent in immature animals, declines rapidly during subsequent development to a minimum by the time of young adulthood, and then reemerges during postmaturational development. Age changes in beta adrenergic-responsive adenylate cyclase activity follow a "U"-shaped curve similar to that described by changes in liver glycogenolytic responsiveness during aging. Developmental and postmaturational changes in beta adrenergic-sensitive adenylate cyclase activation are related to parallel alterations in the density of beta adrenergic receptors and also to functional changes in nonreceptor components of the enzyme. The prevailing view that catecholamines stimulate hepatic glycogenolysis by an alpha adrenergic receptor-mediated, cyclic AMP-independent mechanism is based almost entirely on evidence from young adult male rats. We propose that current concepts of alpha adrenergic-responsive liver glycogenolysis underestimate a physiological role for beta adrenergic responsiveness over the majority of the life span.

Geriatrics grand rounds: Eve's rib, or a revisionist view of osteoporosis in men.

It is widely accepted that estrogen withdrawal following menopause predisposes women to accelerated bone loss and increased risk of developing osteoporosis. Although osteoporosis is a significant public health problem for aging men as well as women, the cause of osteoporosis in men remains largely unknown. A substantial number of men with osteoporosis present with bone loss secondary to conditions associated with reduced gonadal steroid hormone levels. Although hypogonadism is related to bone loss in men, and androgen levels decline with age in men, it is not at all clear that reduced androgen levels are related to bone loss in older men. What, then, is the role of gonadal steroids in osteoporosis in men? This review focuses on recent research--including clinical investigations of men with genetic disorders of estrogen action, basic biomedical studies of estrogen receptor "knockout" mice, and population-based comparisons of bone density with gonadal steroids in older men--leading to the surprising conclusion that estrogen plays a vital role in maintenance of bone in men as well as in women. Possible mechanisms whereby reduced estrogen levels might result in bone loss in both sexes are also reviewed, as are potential therapeutic implications of a role for estrogen in osteoporosis in men.

Modulation by food restriction of intracellular calcium signaling in parotid acinar cells of aging Fischer 344 rats.

Previous studies suggest that alpha 1-adrenergic (alpha 1-AR)-induced intracellular calcium ([Ca2+]i) mobilization in rat parotid acinar cells declines with age. In this study, we examined the effects of food restriction on alpha 1-AR and muscarinic-stimulated [Ca2+]i mobilization in parotid acinar cells during aging. [Ca2+]i levels in response to the alpha 1-AR agonist epinephrine and the muscarinic agonist carbachol were evaluated in Fura-2-loaded parotid acinar cells from ad libitum-fed (AL) and food-restricted (FR) Fischer 344 male rats at 4, 6, 14, and 24 months of age. [Ca2+]i responses to epinephrine and carbachol (10 microM) were significantly reduced (48% and 35%, respectively; p < .05) in cells from 24-month-old AL rats as compared to younger AL rats. In contrast, no significant reduction of epinephrine and carbachol responses was observed in 24-month-old FR animals. An age-related increase in basal [Ca2+]i (peak around 14 months; p < .02) was observed in both AL and FR rats. In addition, basal [Ca2+]i was higher in FR than in AL rats at 14 and 24 months of age (p < .02). These studies suggest that FR partially attenuates or delays age-related impairments in alpha 1-AR- and muscarinic-cholinergic signal transduction systems of parotid acinar cells. Basal [Ca2+]i also appears to be altered during aging and by FR.

Relationship of sex hormone-binding globulin to lipid, lipoprotein, glucose, and insulin concentrations in postmenopausal women.

Sex hormones play a major role in determining the risk of cardiovascular disease. While several studies have shown that reduced sex hormone-binding globulin (SHBG) is associated with increased insulin and triglyceride and decreased high-density lipoprotein cholesterol (HDLC) in premenopausal women, little data are available for postmenopausal women. We hypothesized that in postmenopausal women decreased SHBG would be associated with an atherogenic pattern of cardiovascular risk factors. We measured SHBG, lipids, lipoproteins, glucose, and insulin concentrations, and systolic and diastolic blood pressure in 101 postmenopausal women. SHBG was negatively associated with triglyceride (r = -.21) and insulin (r = -.47) concentrations and positively associated with HDLC concentrations (r = .47). After adjustment for overall adiposity (body mass index) and upper body adiposity (as measured by the ratio of waist to hip circumferences), SHBG was still associated with HDLC and insulin, but not with triglyceride. Sex hormones were not related to systolic and diastolic blood pressure. The results may help to explain an association of increased androgenicity, as measured by a lower SHBG concentration, with diabetes and risk of cardiovascular disease in older women.