The UK Divide: Does Having a Pembrolizumab-Chemotherapy Option in Head and Neck Cancer Matter? Real-world Experience of First-line Palliative Pembrolizumab Monotherapy and Pembrolizumab-Chemotherapy Combination in Scotland.

AIMS: The Scottish Medical Consortium recently approved first-line pembrolizumab monotherapy or in combination with chemotherapy for head and neck squamous cell carcinoma in the palliative setting, contrasting with the decision made by the National Institute for Health and Care Excellence, who approved monotherapy alone in England and Wales. The aim of this study was to provide real-world performance data for first-line pembrolizumab-containing treatments for head and neck squamous cell carcinoma in the palliative setting in Scotland. MATERIALS AND METHODS: We analysed the electronic records of patients who started pembrolizumab-containing treatment between 1 March 2020 and 30 September 2021. Outcomes included overall survival, progression-free survival (PFS), the duration of response and the disease control rate. Data were compared with the KEYNOTE-048 study and clinical factors were evaluated for association with survival. RESULTS: Our cohort included 91 patients (median follow-up 10.8 months). Patient characteristics were similar to those in the KEYNOTE-048 study, although our cohort had a higher proportion of patients with newly diagnosed, non-metastatic disease. For patients receiving monotherapy (n = 76), 12- and 24-month overall survival were 45% and 27%, respectively. For patients receiving pembrolizumab-chemotherapy (n = 15), 12-month overall survival was 60% (24-month overall survival had not yet been reached). Experiencing one or more immune-related adverse event (irAE; versus no irAEs), of any grade, was associated with favourable overall survival and PFS for patients receiving monotherapy in both univariable Log-rank analysis (median overall survival 17.4 months versus 8.6 months, respectively, P = 0.0033; median PFS 10.9 months versus 3.0 months, respectively, P < 0.0001) and multivariable analysis (Cox proportional hazards regression: overall survival hazard ratio 0.31, P = 0.0009; PFS hazard ratio 0.17, P < 0.0001). CONCLUSION: Our real-world data support the KEYNOTE-048 study findings and the value of combination treatment options. Additionally, our data show that irAEs of any grade, as reported in routine clinical records, are associated with better outcomes in this patient group, adding to the growing body of evidence showing that irAEs are generally a positive marker of programmed death-ligand 1 (PD-L1) inhibitor response.

The role of phospholipase C in arginine vasopressin secretion by rat hypothalami in vitro.

The role of phosphatidylcholine (PC) and phosphatidylinositol (PI) specific phospholipase C (PLC) enzymes in the release of immunoreactive arginine vasopressin (ir-AVP) from rat hypothalami in vitro was examined. PC-PLC (0.05-01 U ml-1) increased ir-AVP release but PI-PLC (0.01-0.5 U ml-1) did not. The response to a submaximal concentration of PC-PLC (0.075 U ml-1) was inhibited by the protei kinase C (PKC) inhibitor Ro 31-8220 (40 microM) and by removal of extracellular Ca2+ but was unaffected by the nitric oxide (NO) precursor L-arginine (1 mM), the NO synthase inhibitor N omega-nitro-L-arginine benzyl ester (1 mM) and the phospholipase A2 (PLA2) inhibitors quinacrine (100 microM) and dexamethasone (1 microM). The results suggest that PC-PLC plays an important role in AVP secretion. The responses to PC-PLC appear to be mediated by PKC but not by changes in NO synthase or PLA2 activity.

[3H]L-arginine transport and nitric oxide synthase activity in foetal hypothalamic cultures.

[3H]L-arginine uptake and the conversion of [3H]L-arginine to [3H]citrulline were characterized in foetal hypothalamic cultures. [3H]L-arginine uptake was reduced by L-ornithine (10 microM-1 mM), high extracellular K+ (56 mM), L-glutamate (100 microM) and removal of extracellular Ca2+, but was increased by the nitric oxide synthase inhibitor, Nw-nitro-L-arginine benzyl ester (L-NABE; 1 mM). [3H]citrulline formation was inhibited by L-NABE (1 mM), increased by high extracellular K+ (56 mM) and unaffected by L-glutamate (100 microM). Removal of extracellular Ca2+ reduced [3H]citrulline formation by mixed (neurones and glia) and neurone-enriched cultures but not by glial-enriched cells. The results suggest that [3H]L-arginine uptake into hypothalamic cultures is mediated by the system y+ transporter and is dependent on extracellular Ca2+. [3H]citrulline production in hypothalamic neuronal, but not glial, cells is also dependent on extracellular Ca2+.

Dexamethasone suppresses the release of prolactin from the rat anterior pituitary gland by lipocortin 1 dependent and independent mechanisms.

Glucocorticoids have been shown repeatedly to inhibit the release of prolactin (PRL) in the rat but their site and mode of action is unknown. In the present study, we used an in vitro model to examine the requirement for protein synthesis for dexamethasone to suppress the release of immunoreactive (ir)-PRL release from the rat pituitary gland. In addition we have performed a series of in vitro and in vivo experiments to investigate the potential role in this regard of lipocortin 1 (LC1), a protein shown previously not only to mediate aspects of the anti-inflammatory and anti-proliferative actions of the glucocorticoids but also to contribute to the regulatory actions of the steroids in the brain-neuroendocrine system. In vitro, the release of ir-PRL from rat anterior pituitary tissue initiated by submaximal concentrations of VIP (10 nM). TRH (10 nM) or the adenyl cyclase activator forskolin (100 microM) was reduced significantly (p < 0.01) by preincubation (2 h) of the tissue with dexamethasone (0.1 microM). By contrast, ir-PRL release evoked by a submaximal concentration of the L-Ca2+ channel opener BAY K8644 (10 microM) was unaffected by the steroid although readily antagonised (p < 0.01) by nifedipine (1-100 microM). Exposure of the pituitary tissue to dexamethasone (0.1 microM) also caused a pronounced and highly significant increase in de novo protein synthesis, as assessed by the incorporation of 14C-lysine into the tissue (p < 0.001). This response was reduced markedly by the inclusion of the RNA and protein synthesis inhibitors, actinomycin-D (0.5 micrograms/ml) or cycloheximide (1.0 micrograms/ml), in the incubation medium (p < 0.001), both of which also effectively abrogated (p < 0.01) the dexamethasone-induced inhibition of the release of ir-PRL evoked by TRH. VIP and forskolin. Lipocortin I was readily detectable by Western blotting in protein extracts of freshly excised anterior pituitary tissue: a small proportion of the protein was found to be attached to the outer surface of the cells where it was retained by a Ca(2+)-dependent mechanism. Exposure of the tissue in vitro to dexamethasone (0.1 microM) or corticosterone (0.1 microM) but not 17 beta-oestradiol (0.1 microM) caused a pronounced increase in the amount of LC1 attached to the outer surface of the cells and concomitant decrease in the LC1 content of the intracellular LC1 pool. Addition of an N-terminal LC1 fragment. LC11-188 (10 pg-10 ng/ml), to the incubation medium reduced significantly (p < 0.01) the increases in ir-PRL release induced in vitro by VIP (10 nM) and forskolin (100 microM). By contrast, at all concentrations tested. LC11-188 (10 pg-10 ng/ml) failed to influence (p < 0.05) the highly significant (p < 0.01) ir-PRL response to TRH (10 nM). Similarly, the inhibitory actions of dexamethasone (0.1 microM) on the release of ir-PRL induced by VIP (10 nM) or forskolin (100 microM) but not by TRH (10 nM) were substantially reversed (p < 0.01) by a specific monoclonal anti-LC1 antibody while an isotype-matched control antibody was without effect. In vivo, rats pretreated with either a polyclonal anti LC1 antiserum (anti-LC1 pAb, 1 ml/day s.c. for 2 days) or a corresponding volume of non-immune sheep serum (NSS) responded to stress (laparotomy under ether anaesthesia) with significant (p < 0.05) increases in the serum ir-PRL concentration. In the NSS-treated group, the ir-PRL response to stress was effectively inhibited by dexamethasone (100 micrograms/kg i.p.) which had no effect on the pre-stress serum ir-PRL concentration. By contrast, in rats pretreated with anti-LC1 pAb dexamethasone failed to block the stress-induced release of ir-PRL. The results show clearly that the inhibitory actions of dexamethasone on PRL release are dependent on de novo protein synthesis and provide novel evidence for the involvement of both LC1-dependent and LC1-independent mechanisms.

Lipocortin 1 mediates an early inhibitory action of glucocorticoids on the secretion of ACTH by the rat anterior pituitary gland in vitro.

Lipocortin 1 (LC1), a mediator of anti-inflammatory steroid action in some peripheral tissues, may contribute to the acute inhibitory effects of these steroids on hypothalamo-pituitary-adrenal (HPA) function. Accordingly, in the present study we have used an in vitro model to examine the potential role of this protein in the regulation of the release of corticotrophin (ACTH) from the anterior pituitary gland. Hypothalamic extracts (0.05-0.4 HE/ml), the 41 amino acid corticotrophin-releasing factor (CRF-41, 1-100 nM), the adenyl cyclase stimulator, forskolin (0.1 microM-10 mM), and the L-Ca2+ channel opener, BAY K8644 (0.01-10 mM), all caused concentration-dependent increases in the release in vitro of immunoreactive (ir)-ACTH from segments of rat anterior pituitary tissue. The secretory responses to submaximal concentrations of these secretagogues were overcome by preincubation of the tissue with dexamethasone (0.1 and 1 microM). LC1 was readily detectable by Western blotting in protein extracts of freshly excised pituitary tissue; a small proportion of the protein was found to be attached to the outer surface of the cell membranes where it was retained by a Ca(2+)-dependent mechanism. Exposure to dexamethasone (0.1 microM) in vitro did not affect the total LC1 content of the pituitary tissue but, over a 2-hour period, it caused a progressive two- to fivefold increase in the amount of LC1 attached to the outer surface of the cell; this response developed in parallel with the inhibitory effects of the steroid on ir-ACTH release. Both the dexamethasone-induced 'externalization' of LC1 by the pituitary tissue and the concomitant steroid-induced inhibition of peptide release were blocked by cycloheximide (1.0 microgram/ml) but not by actinomycin D (0.5 microgram/ml). A stable N-terminal lipocortin 1 fragment, LC1(1-188) (10 pg-10 ng/ml), attenuated (p < 0.01) the release of ir-ACTH evoked by HE (0.1 HE/ml), CRF-41 (1 nM), forskolin (1 mM) and BAY K8644 (1 nM). Conversely, inclusion of the anti-LC1 antibody in the medium substantially overcame the inhibitory effects of dexamethasone (0.1 microM) on the release of ir-ACTH evoked by the secretagogues whilst a control isotype matched antibody was without effect. The results suggest that LC1 plays a key role in effecting the acute inhibitory actions of glucocorticoids on the secretion of ir-ACTH by the rat anterior pituitary gland.

Modulation of the hypothalamo-pituitary-adrenocortical responses to cytokines in the rat by lipocortin 1 and glucocorticoids: a role for lipocortin 1 in the feedback inhibition of CRF-41 release?

Our recent studies indicate that lipocortin 1 (LC1), a putative second messenger protein for the anti-inflammatory steroids in peripheral tissues, may also contribute to the regulatory actions of the glucocorticoids on the hypothalamo-pituitary-adrenal axis. In the present study we have used in vitro and in vivo models to compare the effects of adrenalectomy, LC1 and dexamethasone on the cytokine-induced secretion of the 41-amino acid corticotrophin releasing factor (CRF-41) and arginine vasopressin (AVP) by the rat hypothalamus. In addition, western blot analysis was used to examine the influence of dexamethasone on the expression of LC1 in the hypothalamus. In vitro, interleukins- (IL-) 1 alpha (100 and 200 pg/ml), 1 beta (0.5 and 1.0 ng/ml) and 8 (0.25-1.0 ng/ml) readily initiated the release of CRF-41 and AVP from hypothalami removed from intact rats. IL-6 (10 and 20 ng/ml) was also an effective CRF-41 secretagogue but, unlike the other interleukins tested, it was ineffective with regard to AVP. Adrenalectomy 7-14 days prior to autopsy increased significantly (p < 0.01) the magnitude of the CRF-41 responses to IL-1 alpha, IL-1 beta and IL-6 but not to IL-8. In contrast however, while hypothalamic tissue from adrenalectomized rats, unlike that from intact animals, responded to IL-6 (5-20 ng/ml) with a pronounced hypersecretion of AVP, the AVP responses to IL-1 alpha and IL-1 beta were largely unaffected by adrenalectomy as too were those to IL-8. The marked increases in CRF-41 and AVP release from hypothalami from adrenalectomized rats initiated in vitro by IL1 alpha, IL-1 beta, IL-6 and IL-8 were readily overcome by preincubation of the tissue with dexamethasone (10(-7) M). In addition, the steroid caused 'externalization' of two species of immunoreactive (ir-) LC1 (37 and 58 kDa) by the hypothalamic cells but failed to influence the total LC1 content of the tissue. The inhibitory effects of dexamethasone on the cytokine-induced release of CRF-41 in vitro were mimicked by LC1 (10 ng/ml) which alone had no effect on the basal release of the peptide. However, unlike dexamethasone, LC1 failed to influence the concomitant release of AVP from the hypothalamic tissue elicited by IL1 alpha, IL-1 beta or IL-8 and potentiated that evoked by IL-6.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of lipocortin 1 and dexamethasone on the secretion of corticotrophin-releasing factors in the rat: in vitro and in vivo studies.

Lipocortin 1 (LC1: also called annexin 1) was first described as a putative second messenger protein for the anti-inflammatory steroids in peripheral tissues. In the present study, in vitro and in vivo methods were used to examine its potential role within the hypothalamus as a mediator of the regulatory actions of the glucocorticoids on the hypothalamo-pituitary-adrenocortical axis of the rat. In the in vitro studies, the effects of human recombinant LC1 (hu-r-LC1) on the concomitant release of the two major corticotrophin-releasing factors (CRF-41 and arginine vasopressin, AVP) from isolated hypothalami removed from chronically adrenalectomized rats were compared with those of dexamethasone in the presence and absence of appropriate secretagogues, namely phospholipase A2 (PLA2), interleukin-6 (IL-6) and a non-specific depolarizing agent, K+ (56 mM). The spontaneous release of CRF-41 in vitro was unaffected by either hu-r-LC1 (5 to 100 ng/ml) or dexamethasone (1 microM). Both compounds however reduced the release of the neuropeptide evoked by IL-6 (5 ng/ml) but failed to modify the secretory responses to PLA2 (25 U/ml) or K+ (56 mM). Dexamethasone (1 microM) had no effect on the basal release of AVP but effectively blocked the secretion of the peptide induced by either IL-6 (10 ng/ml) or PLA2 (25 U/ml). In complete contrast, hu-r-LC1 (5 to 100 ng/ml) stimulated the release of AVP and potentiated the secretory responses to IL-6 (10 ng/ml) and PLA2 (25 U/ml) but not to K+ (56 mM). The hypothalamic responses to PLA2 stimulation (25 U/ml) were associated with significant (P < 0.01) increases in prostaglandin E2 release which, in some instances, were potentiated by hu-r-LC1 (5 to 20 ng/ml). In vivo, administration of histamine (0.6 mg/100 g body wt, ip) produced significant (P < 0.01) increases in the serum corticosterone concentration and in the hypothalamic LC1 content. Neither hu-r-LC1 (0.6 to 1.2 micrograms) nor a polyclonal anti-LC1 antibody (3 microliters, diluted 1:200), injected intracerebroventricularly (icv), influenced either the resting serum corticosterone concentration or the hypersecretion of the steroid evoked by histamine stress. A lower dose of the recombinant protein (0.3 micrograms icv) also failed to alter basal corticosterone release but, in contrast to the higher doses, potentiated the pituitary-adrenocortical responses to histamine. The results suggest that LC1 may contribute to some aspects of peptide release in the hypothalamus but that its actions are not necessarily related to those of the glucocorticoids.

Acute tularemia in three domestic cats.

Acute Francisella tularensis infection in 3 domestic cats was presumptively diagnosed on the basis of clinical signs and lesions and confirmed by culturing or immunofluorescent demonstration of the organism. Clinical findings include marked signs of depression, oral/lingual ulceration, regional or generalized lymphadenomegaly, hepatosplenomegaly, panleukopenia with severe toxic change of neutrophils, and hyperbilirubinemia with bilirubinuria. Lesions found at necropsy included icterus, oropharyngeal and lingual ulceration, multiple foci of necrosis in lymph nodes, spleen, liver, and lung, and severe segmental or diffuse enterocolitis. Results of serologic testing for F tularensis was positive in only 1 of the 3 cats. The organism was cultured aerobically from several tissues, including aspirated bone marrow obtained before death in 1 cat. Results of an indirect fluorescent antibody test, performed on fresh and formalin-fixed tissues of all cats, were positive. Because of the severe clinical course, opportunity to evaluate therapeutic regimens was not possible. Until now, confirmed diagnosis of feline tularemia only has been made retrospectively, in instances when cats were suspected to have transmitted infection to human beings in whom the primary diagnosis was made. The findings in this report provide a basis for presumptive diagnosis that will help to minimize public health risk associated with this potentially fatal zoonotic disease.

Studies on the roles of phospholipase A2 and eicosanoids in the regulation of corticotrophin secretion by rat pituitary cells in vitro.

Dispersed anterior pituitary cells were used to investigate the possible roles of phospholipid metabolites released by phospholipase A2 (PLA2) in the control of immunoreactive ACTH (ir-ACTH) secretion in vitro. PLA2 (15,600-62,500 U/l), the PLA2 activator melittin (0.5-20 mg/l) and arachidonic acid (1 mmol/l) all produced increases in ir-ACTH release from the cells, whilst platelet-activating factor (PAF), prostaglandin F2 alpha (PGF2 alpha), the prostacyclin analogues iloprost and BW245C, the thromboxane A2 (TXA2) analogue U46619, and the leukotrienes LTB4 and LTC4 were ineffective in this respect. PGF2 alpha (100 nmol/l and 1 mumol/l), iloprost (1 mumol/l) and BW245C (100 nmol/l and 1 mumol/l) depressed corticotrophin-releasing factor-41-induced ir-ACTH secretion, while the PAF antagonist BN52021 (10 and 100 mumol/l) and LTC4 (100 nmol/l and 1 mumol/l) had no discernable effects. The secretory responses of the cells to hypothalamic extracts (0.2 hypothalami/ml) and arachidonic acid (1 mmol/l) were generally unaffected by the cyclooxygenase inhibitors ibuprofen (10 and 100 mumol/l) and indomethacin (10 mumol/l), the TXA2 synthetase inhibitor imidazole (10 mumol/l-1 mmol/l), the lipoxygenase inhibitor nordihydroguaiaretic acid (10 and 100 mumol/l) and the dual cyclo-oxygenase/lipoxygenase inhibitors phenidone (1-100 mumol/l) and BW755C (10 and 100 mumol/l). They were, however, inhibited by the dual cyclo-oxygenase/lipoxygenase inhibitor eicosatetraynoic acid (10 and 100 mumol/l), which also blocks epoxygenase and PLA2 activity and by the cytochrome P450 inhibitor SKF-525A (1 mmol/l). The results suggest that the stimulatory effects of PLA2 and arachidonic acid on ir-ACTH secretion are not effected by products generated by the cyclo-oxygenase or lipoxygenase pathways but may be mediated by metabolites generated by the cytochrome P450 pathway.

Severe systemic reactions to Hymenoptera stings in three dogs.

Three dogs were treated for acute severe systemic reactions following Hymenoptera stings. The reactions were characterized clinically by CNS depression, shock, and hemorrhage, and clinicopathologically by inflammation, liver injury, renal disease, hypoproteinemia, and possible disseminated intravascular coagulation. The severe systemic reaction may have resulted from allergic mechanisms, toxic, nonimmunologic mechanisms, or both. Rapid correction of hypovolemia and prevention of vascular stasis are the most important aspects of treatment.