Survival outcomes in pediatric patients with metastatic Ewing sarcoma who achieve a rapid complete response of pulmonary metastases

PURPOSE

Our objectives were to compare overall survival (OS) and pulmonary relapse between patients with metastatic Ewing sarcoma (EWS) at diagnosis who achieve rapid complete response (RCR) and those with residual pulmonary nodules after induction chemotherapy (non-RCR).

PATIENTS AND METHODS

This retrospective cohort study included children under 20 years with metastatic EWS treated from 2007 to 2020 at 19 institutions in the Pediatric Surgical Oncology Research Collaborative. Chi-square tests were conducted for differences among groups. Kaplan-Meier curves were generated for OS and pulmonary relapse.

RESULTS

Among 148 patients with metastatic EWS at diagnosis, 61 (41.2%) achieved RCR. Five-year OS was 71.2% for patients who achieved RCR, and 50.2% for those without RCR (p = .04), and in multivariable regression among patients with isolated pulmonary metastases, RCR (hazards ratio [HR] 0.42; 95% confidence interval [CI]: 0.17-0.99) and whole lung irradiation (WLI) (HR 0.35; 95% CI: 0.16-0.77) were associated with improved survival. Pulmonary relapse occurred in 57 (37%) patients, including 18 (29%) in the RCR and 36 (41%) in the non-RCR groups (p = .14). Five-year pulmonary relapse rates did not significantly differ based on RCR (33.0%) versus non-RCR (47.0%, p = .13), or WLI (38.8%) versus no WLI (46.0%, p = .32).

DISCUSSION

Patients with EWS who had isolated pulmonary metastases at diagnosis had improved OS if they achieved RCR and received WLI, despite having no significant differences in rates of pulmonary relapse.

Biliary intervention rates during neoadjuvant therapy for adenocarcinoma of the pancreatic head

BACKGROUND

Neoadjuvant therapy prior to resection of adenocarcinoma of the pancreatic head increases time to surgery and thus the possibility of biliary complications. We hypothesized that biliary complications during neoadjuvant therapy negatively impact clinical outcomes.

METHODS

We completed a retrospective study of a cohort of borderline resectable patients consistently treated with neoadjuvant therapy from May 2014 through March 2019. Biliary complications were defined as new-onset biliary obstruction, existing stent failure, cholecystitis, and cholangitis.

RESULTS

Of 59 patients that met inclusion criteria, 34 (57.6%) went on to resection. Biliary complications affected 16 patients (27%); 8 (50%) of these patients went on to surgical resection. Of those 43 patients who did not have a biliary intervention, 26 went on to surgical resection (60.4%). There was no significant effect of a biliary complication on total number of chemotherapy cycles (p = 0.12), proceeding to surgical resection (p = 0.56) or on median survival (p = 0.23). Among patients who did proceed to surgery, there was a notable difference in median survival for patients who required a biliary intervention (17.9 vs 31.0 months) that did not reach significance (p = 0.35).

CONCLUSION

The need for further biliary interventions during neoadjuvant therapy for pancreatic adenocarcinoma is common, but does not appear to have a significant effect on number of cycles of neoadjuvant therapy or proceeding to surgical resection. Larger studies are necessary to determine if these events compromise overall survival.

Pars intermedia peptides: studies in adult humans

A combination of radioimmunoassays and chromatography under acid-dissociating conditions has been used to obtain profiles of ACTH and LPH-related peptides in human plasma and cerebrospinal fluid. The spectra of peptides observed in these two fluids differ markedly. ACTH, beta-LPH, gamma-LPH and beta-endorphin are observed in the plasma of normal subjects and patients with increased pituitary ACTH secretion, whereas cerebrospinal fluid contains ACTH, beta-LPH, gamma-LPH and beta-endorphin, a 31 000-molecular-weight putative precursor having ACTH, LPH and gamma-MSH immunoreactivities, as well as pro-gamma-MSH(1-77) and smaller immunoreactive gamma-MSH fragments, alpha-MSH was not observed in blood or cerebrospinal fluid but this pars intermedia peptide and corticotropin-like intermediate lobe peptide (CLIP) were both found in tumour tissues obtained from patients with the ectopic ACTH syndrome. In vitro studies of human pituitary tumour tissues confirmed concomitant secretion of ACTH, beta-LPH, gamma-LPH, beta-endorphin and pro-gamma-MSH, which could be stimulated by a preparation of crude stalk median eminence and synthetic arginine vasopressin, from the rat, and could be suppressed by hydrocortisone. Clinical studies in which electroacupuncture was used to alleviate the symptoms of heroin withdrawal or recurrent pain revealed that concentrations of met-enkephalin and beta-endorphin, respectively, may rise in cerebrospinal fluid in association with relief of symptoms.

Flocculation and Coalescence of Oil-in-Water Poly(dimethylsiloxane) Emulsions

The stability of poly(dimethylsiloxane) (PDMS) oil-in-water emulsions has been investigated in the presence of added NaCl as well as in the presence of added surfactant. The emulsions were prepared using a combination of nonionic (C(x)E(y), x and y represent the number of methylene (C) and ethylene oxide (E) groups, respectively) and cationic (quarternary alkylammonium) surfactants. The droplets were observed to exhibit weak flocculation in the presence of high NaCl concentration (1 M). Phase separation and optical microscopic observations revealed that the principal mechanism for emulsion destabilization at high salt concentration was coalescence, which was accelerated at elevated temperature (50 degrees C). The effective coalescence rate for diluted emulsions was investigated using photon correlation spectroscopy. The small effective Hamaker constant for PDMS is the primary reason for the slow rate of coalescence observed for the emulsions at neutral pH in the presence of NaCl. The stability of PDMS emulsions to flocculation is qualitatively similar to that reported for low Hamaker constant dispersions (e.g., microgel particles). Addition of cationic surfactants (cetyltrimethylammonium chloride and dodecyl dimethylbenzylammonium chloride) to the negatively charged droplets after preparation was shown to decrease the emulsion stability once the surfactant concentration exceeded the CMC. Electrophoretic mobility measurements showed that added cationic surfactant changed the sign of the droplet charge from negative to positive at concentrations well below the CMC. Charged micelles of the same sign as the droplets are electrostatically excluded from close approach to the droplet surface within a distance (varepsilon) which results in depletion flocculation. Copyright 2000 Academic Press.

Developing hypothalamic dopaminergic neurones as potential targets for environmental estrogens

Environmental chemicals which mimic the actions of estrogen have the potential to affect any estrogen responsive tissue. The aim of the present study was to investigate their potential to mimic the effects of 17beta-estradiol (E2) on developing primary rat hypothalamic dopaminergic (DA) neurones maintained in a chemically defined medium. We now show that both E2 and octylphenol (OP), but not the non-aromatizable androgen, dihydrotestosterone, enhanced the uptake of [3H]DA by the cultured cells, whereas they had no effect on the uptake of [14C]GABA. Although the sensitivity of responses may change with the age of the developing cultures, the dose response curves for E2 and OP were typically 'bell-shaped', with a rise in response followed by a decline to control levels with increasing concentrations. Effects were seen as low as 10(-14) M for E2 and 10(-11) M for OP. Responses to E2 (10(-12) M) and OP (10(-9) M) were reversed in the presence of the antiestrogen, ZM 182780 (10(-5) M). This study thus provides direct evidence, using a mechanistic rather than toxicological end-point, in support of the hypothesis that inappropriate exposure to environmental estrogens at critically sensitive stages of development, could potentially perturb the organisational activities of estrogen on selected neuronal populations in the CNS.

Somatostatin: the neuroendocrine story

Since its original discovery as the neuroendocrine hormone responsible for inhibiting growth hormone (GH) secretion, our understanding of the functions of somatostatin [or somatotrophin release inhibitory hormone (SRIH)], both in the periphery and the CNS, has grown enormously. With the cloning of five SRIH receptors, much interest has centred recently on the potential use of SRIH analogues in the treatment of clinical conditions ranging from human cancers to Alzheimer's and Parkinson's diseases. There is a growing recognition that the physiological functions of GH also need to be extended beyond its role in growth control, e.g. to a role in the maintenance of normal immune, cardiovascular and reproductive functions. Here, Glenda Gillies addresses the importance of somatostatinergic systems in regulating the sexually dimorphic patterns of GH secretion as well as their influence on other endocrine hormones. She also considers the neurotransmitter/neuromodulator actions of SRIH within the hypothalamus, where it is involved in the neural control and integration of many aspects of endocrine function, as well as its potential role in the maturation of the hypothalamus during the critical perinatal period.

Modulation of arginine vasopressin secretion from cultured ovine hypothalamic cells by glucocorticoids and opioid peptides

In sheep, arginine vasopressin (AVP) appears to be a more potent ACTH-releasing factor than ovine corticotrophin-releasing hormone. In order to investigate the neuroendocrine regulation of AVP secretion we have developed a novel system for maintaining fetal ovine hypothalamic neurones in serum-free culture. Hypothalamic neurones derived from fetal sheep at day 70 gestation (term = 145 days) secreted AVP under basal conditions and in response to repeated potassium-induced depolarizations, for up to 35 days in vitro. AVP secretion was time- and calcium-dependent. AVP secreted from ovine hypothalamic cells co-eluted with synthetic AVP on a Sephadex chromatography column and diluted in parallel with AVP standard in the radioimmunoassay. The addition of cortisol (150 nM) to medium bathing ovine hypothalamic cells significantly inhibited basal, and potassium-induced AVP secretion without altering the AVP content of the cell cultures. Furthermore, the opioid peptide [D-Pro10]Dynorphin(1-11) which acts via the kappa opioid receptor, significantly inhibited basal and potassium-stimulated AVP secretion, an effect which was abolished when cells were cultured in the presence of cortisol. These data show that hypothalamic AVP is a site for negative feedback regulation within the ovine hypothalamic-pituitary-adrenal axis. Furthermore, these data suggest that the kappa opioid system inhibits AVP secretion from ovine hypothalamic neurones, a response which is modulated by glucocorticoids.

Met-enkephalin secretion from mixed cultures of hypothalamic neurons and astrocytes

Release of the endogenous opioid pentapeptide, met-enkephalin, from primary cultures of dissociated fetal rat hypothalamic cells was studied using an assay system which could both measure and differentiate between free met-enkephalin and the larger enkephalin-containing peptides (ECPs), which are the processing intermediates of the enkephalin precursor. The cultures were maintained in fully defined, serum-free medium and contained both neurons and astrocytes. Free met-enkephalin was secreted from the cultures in significant quantities in response to nonspecific depolarisation with 56 mM potassium, by a mechanism dependent upon extracellular calcium. Under basal conditions, barely detectable amounts of free peptide were released, whereas ECPs were secreted in significant quantities which were not reduced by the removal of extracellular calcium. As the period of culture increased, so did the quantitative importance of this constitutive ECP secretion, relative to the stimulated release of free peptide. Treatment of the cultures with the cytotoxic agent, cytosine arabinoside, attenuated this temporal increase of ECP secretion, whilst leaving the stimulated release of free met-enkephalin relatively unaffected. This suggested that the met-enkephalin secretion seen within the cultures reflected the presence of at least two distinct enkephalinergic cell types and that the change in the nature of the secreted enkephalin was at least in part, due to the proliferation of one of these cell populations. These results are consistent with secretion of met-enkephalin from both neurons and astrocytes within these cultures. We propose that the neurons secreted essentially fully processed peptide in a regulated manner, whilst the mitotic glial cells constitutively secreted non- or partially processed precursor peptides.(ABSTRACT TRUNCATED AT 250 WORDS)

GABAergic influences on somatostatin secretion from hypothalamic neurons cultured in defined medium

The effects of GABAergic influences intrinsic to the hypothalamus on the secretion of somatostatin were studied using cultured fetal rat hypothalamic neurons. The existence of GABAergic neurons within the cultures was confirmed by immunocytochemistry. These neurons appeared to be actively secreting GABA as antagonism of GABAA receptors with bicuculline and picrotoxinin caused a dose-dependent increase in the release of immunoreactive somatostatin (SRIF), which was Ca(2+)-dependent. Although exogenous GABA inhibited SRIF secretion at concentrations of 10(-6) M and greater, muscimol, a GABAA agonist, inhibited SRIF release at 10(-8) M, whereas baclofen, a GABAB agonist, required concentrations two orders of magnitude greater to produce an effect. Phaclofen, a GABAB antagonist, was inactive (10(-8)-10(-4) M). A GABA uptake inhibitor, SKF 89976A, produced a dose-dependent inhibition of SRIF release. These results, therefore, support a role for intrahypothalamic GABA neurons in the regulation of SRIF secretion in the neonatal rat, predominantly via a type A receptor, and provide further evidence for a neuroendocrine role for GABA in controlling growth hormone secretion.

A double-blind single dose comparison of intramuscular ketorolac tromethamine and pethidine in the treatment of renal colic

The efficacy of a single dose of intramuscular ketorolac 10 mg or 90 mg was compared with pethidine 100 mg in a randomized double-blind study in 121 patients reporting at least moderate pain due to renal colic. Pain was assessed before drug administration, and then at 1 hour and 12 hours after the dose. Sedation was also assessed at these times, and additionally at the 12 hour assessment the time of the next analgesic dose was recorded. At 1 hour after dosing, pain scores had decreased in all groups; the largest decrease was seen in the ketorolac 90 mg group. The difference in the decrease was significant between the two ketorolac groups, but the differences between ketorolac and pethidine were not significant. Fewer patients in the ketorolac 90 mg group (17%) required a further dose of analgesic within 10 hours than in either the ketorolac 10 mg group (39%) or the pethidine 100 mg group (47%). The difference between ketorolac 90 mg and pethidine 100 mg was statistically significant. At both assessment times the proportion of patients with no sedation was higher in the two ketorolac groups than in the pethidine group. The overall incidence of adverse events was low with all drugs, notably so for the occurrence of vomiting after ketorolac. The results of the study show that intramuscular ketorolac is efficacious in the treatment of renal colic.

Interleukin-1 directly stimulates the release of corticotrophin releasing factor from rat hypothalamus

While interleukin-1 (IL-1), a monocyte-derived polypeptide, clearly stimulates the hypothalamo-pituitary-adrenal (HPA) axis, its precise site of action is controversial. In these studies, the possibility of a hypothalamic and/or a pituitary site of action was investigated in vitro, using incubated rat hypothalami and perifused dispersed pituitary cells. Both forms of IL-1, IL-1 alpha and IL-1 beta, produced a dose-dependent stimulation of CRF-41 release from incubated rat hypothalami in the dose range of 1-100 U/ml (p less than 0.01). However, concentrations of both interleukins of 1-1,000 U/ml given as 10-min infusions had no effect on ACTH release from dispersed pituitary cells. Moreover, IL-1 beta, used in the concentration range of 1-100 U/ml, was unable to potentiate CRF-41-induced ACTH release. These data therefore provide evidence that at least the acute stimulatory effects of IL-1 on the HPA axis are predominantly mediated via a direct stimulation of hypothalamic CRF-41, suggesting that the hypothalamus may provide an interface between the neuroendocrine and immune axes.

Assessment of corticotropin-releasing factor, vasopressin and somatostatin secretion by fetal hypothalamic neurons in culture

The concomitant release of corticotropin-releasing factor (CRF), vasopressin (AVP) and somatostatin (SRIF) has been followed from primary cultures of rat hypothalamic neurons. 18-day-old fetal rat hypothalami were dissociated enzymatically and mechanically, then plated and maintained in a serum-containing medium at a density of 2.5 x 10(6) cells per dish (equivalent to 3 hypothalami). Cultured neurons remained viable for up to 6 weeks, and peptide release was followed by immuno-assay between days 14 and 39 in culture. The incubation media were concentrated on C4 and C8 silica columns to facilitate detection of CRF and AVP. Peptide release was measured at various times up to 4 h, at which point it was still increasing. To optimise measurements, taking into account peptide degradation, a 1-hour incubation period was chosen for further studies. Release of CRF, AVP and SRIF by 56 mM K+ or 10 microM veratridine was statistically significantly greater than basal (p less than 0.01) and was Ca2-dependent. For CRF and AVP, stimulated release increased considerably with the age of culture, whereas SRIF release was steadier. Basal release for all 3 peptides did not fluctuate greatly over this period. Basal and stimulated release of the peptides continued over at least 5 successive 1-hour periods. At day 35 of culture, the peptide content was still increasing in a pattern which paralleled the increasing content in hypothalami freshly removed from age-matched rats. In conclusion, we have demonstrated a development of CRF, AVP and SRIF production by neurons over extended periods in culture as assessed by their peptide content and increasing responses to depolarizing stimuli.(ABSTRACT TRUNCATED AT 250 WORDS)

The CRFs and their control: chemistry, physiology and clinical implications

The 41-amino acid CRF fulfils all the criteria for a corticotrophin releasing factor, although considerable evidence suggests that other factors, particularly VP, also play a physiologically significant role in controlling ACTH release. Although human CRF has now been identified as a 41-residue peptide, most studies to date have used oCRF-41 in their exploration of the physiology and pathology of the hypothalamic--pituitary--adrenal axis. Low doses of oCRF-41 appear to be safe, and for specific tests of the readily-releasable pool of ACTH and related peptides 100 micrograms is a practical dose for most purposes. Although serious side-effects have only been noted at doses above 100 micrograms, it is reasonable to monitor all patients administered CRF-41 with great care, and in particular to be alert to hypotension, especially in patients with corticosteroid deficiency. There is little doubt that, in combination with the standard insulin-tolerance test, the CRF test is a useful means of diagnosing hypothalamic or portal dysfunction in patients with secondary adrenal failure. However, in the diagnosis and differential diagnosis of Cushing's syndrome, the role of the CRF test remains unclear. In normal subjects, a high basal cortisol level usually inhibits the response to CRF, such that a greatly enhanced response is suggestive of pituitary-dependent Cushing's syndrome. In patients with diagnosed ACTH-dependent Cushing's syndrome, an absent response to CRF predisposes towards an ectopic source of ACTH. However, there are exceptions in all directions, and it is uncertain whether the CRF test will prove of greater value than the traditional procedures, such as the dexamethasone suppression test. The differential diagnosis of depression and Cushing's disease may be its greatest value. In terms of treatment, there are as yet few data on the usefulness of CRF in expediting recovery of the pituitary-adrenal axis following long-term suppression, such as in patients with Cushing's syndrome treated by removal of a unilateral adenoma or trans-sphenoidal microadenomectomy. It is possible that such treatment may eventually be a useful application of CRF, although data are not yet available.

Involvement of rat corticotrophin-releasing factor-41-related peptide and vasopressin in adrenocorticotrophin-releasing activity from superfused rat hypothalami in vitro

Superfused rat hypothalamic pieces stimulated with a high K+ medium released corticotrophin-releasing factor (CRF) as detected in the rat isolated anterior pituitary cell column bioassay. This activity has components related to ovine CRF-41 (oCRF-41) and vasopressin as assessed by the effects of specific antisera on the ACTH-releasing activity of the hypothalamic column effluent. Release of immunoactive vasopressin paralleled that of CRF bioactivity. Immunoactive oCRF-41 could not be detected, as it is likely to be below the sensitivity of present radioimmunoassays.

Pro-opiocortin related peptides in human pituitary and ectopic ACTH secreting tumours

Basal and stimulated secretion of N-terminal pro-opiocortin (Pro-gamma-MSH), ACTH and LPH from seven pituitary and three ectopic ACTH secreting tumours have been studied in vitro using a perfused isolated cell system. The peptides were shown to be released concomitantly and in equimolar amounts. The pituitary tumours responded to stimulation with rat stalk median eminence extracts (SME) and synthetic AVP. However, peptide release from the ectopic tumours, although pulsatile, remained autonomous. Prior to surgery, gel-chromatographic profiles of plasma immunoreactive ACTH showed only one peak, which eluted in the position of 1-39 ACTH, in patients with the pituitary tumours, but there was a second peak of large molecular weight ACTH present in the plasma from those with the ectopic ACTH syndrome. This second form of ACTH could not be detected in any of the tumour cell column effluents. An eighth pituitary tumour was atypical, in its unusually large size, clinically aggressive nature and spectrum of peptide release. Although peptide release in response to stimulation with SME was similar to that observed with the other pituitary tumours, the chromatography of the plasma ACTH resembled the ectopic plasma pattern, showing two peaks of immunoreactivity.

Acute membrane responses to viral action

The effects of Sendai, a paramyxovirus, on the functional activity of 3 cell types, have been studied in vitro to establish whether a virus alone can cause pathophysiological changes. Neuronal cells are depolarized and suffer a loss of excitability which was attributed to an increase in membrane conductance. Spontaneously beating cardiac cells initially stop beating and then beat more rapidly and asynchronously. Anterior pituitary cells release hormones. In all 3 cases the effects are transient and the cells recover completely.

Investigation into the hypogonadism of the obese mouse (genotype ob/ob)

Features of the reproductive axis in the genetically hypogonadal, obese mouse (genotype, ob/ob) were examined at 5-8 months of age and compared with those of wild-type litter mates. Hypothalamic concentrations of dopamine and 5-hydroxytryptamine were normal. Those of 5-hydroxyindoleacetic acid, noradrenaline and LH-RH were raised. LH-RH was biologically active. Pituitary concentration of LH was normal, but that of FSH was raised. Serum concentrations of LH and FSH, compared with those of wild-type animals, were normal and low, respectively. Gonad and accessory sex organs weights were reduced. These findings suggest that the release of FSH but not LH is defective in the ob/ob mouse. Preliminary in-vitro experiments indicated that the pituitary gland responded normally or even supernormally towards LH-RH in its release of LH. The defect in the reproductive axis of the obese mouse may be due to inadequate release of LH-RH although an insensitivity of the pituitary gland towards LH-RH in its release of FSH cannot be excluded.

Angiotensin II stimulates the release of ACTH from dispersed rat anterior pituitary cells

In a rat anterior pituitary dispersed cell system, angiotensin II was found to stimulate the release of ACTH at concentrations ranging from 100 pmol/l to 1 mumol/l, with a maximal response being given by 10 nmol/l. The angiotensin II antagonist, saralasin, was able to block completely at a concentration of 1 mumol/l the stimulation of ACTH induced by 10 nmol/l angiotensin II, but had no effect on the basal release. The log dose-response curve for ACTH release by angiotensin II was shifted to the right in a parallel fashion by saralasin 10 nmol/l, suggesting competitive antagonism. The stimulation of ACTH release by a rat stalk-median eminence extract or by arginine vasopressin was unaffected by saralasin. The data are interpreted as suggesting that rat corticotrophs contain angiotensin II receptors, and that these may be involved in ACTH release in response to hypovolaemic stress.

Adrenocorticotropin and lipotropin secretion by dispersed cell cultures of a human corticotropic adenoma: effect of hypothalamic extract, arginine vasopressin, hydrocortisone, and serotonin

Basal and modulated secretion of ACTH and lipotropin (LPH) by cultures of trypsin-dispersed cells of a biopsy of a human corticotropic adenoma have been examined. ACTH secretion was detectable throughout the period of culture (13 days) but declined steadily from an initial production rate of 238 +/- 124 ng/3 X 10(5) cells/12 h. The time course of secretion showed a slower phase over the first 4 h, with increases up to 12 h. An extract of rat stalk median eminence caused a significant (P less than 0.005) dose-dependent increase in both ACTH and LPH secretion during 30 min. The patterns of response for ACTH and LPH were very similar; both exhibited a decline in the basal release of peptide subsequent to the period of stimulation. The addition of hydrocortisone (0.2 micrograms/ml) did not suppress basal ACTH secretion during 30 min but significantly (P less than 0.05) inhibited stimulation produced by rat stalk median eminence extract. Arginine vasopressin (dose range, 1-9 ng/ml) significantly (P less than 0.025) stimulated both ACTH and LPH secretion during 30 min. The patterns of response were again very similar. Serotonin (dose range, 0.01-10 micrograms/ml) did not affect ACTH secretion during incubations of 30 min to 4 h. The results obtained with the cell cultures of a human corticotropic cell adenoma concur with in vivo findings of incomplete autonomy of secretion, parallel secretion of ACTH and LPH in response to provocative stimuli, and suppression by corticosteroids. The technique has potential for exploring the cellular mechanisms controlling secretion by human corticotropic adenomas as well as the nature of the hormones produced.

Secretion of ACTH, LPH and beta-endophin from human pituitary tumours in vitro

Basal and stimulated secretion of immunoreactive ACTH, LPH and beta-endorphin from four human pituitary tumours has been studied in vitro using a superfused, isolated cell system. Chromatography of cell secretions under acid-dissociating conditions demonstrated that the human tumor cells released immunoreactive peptides with the elution profiles of alpha h (1-39) ACTH, beta h-LPH, gamma h-LPH and beta h-endorphin confirming that beta h-endorphin is secreted by human pituitary tumour cells and is not formed by enzymic cleavage from beta h-LPH in blood. No alpha- or beta h-MSH, nor any higher molecular weight forms of ACTH or LPH were detected. The cells from all four tumours responded to stimulation with rat stalk-median eminence extract (SME) and synthetic AVP with a concomitant release of ACTH, beta-LPH, gamma-LPH and beta-endorphin. In contrast to the isolated rat anterior pituitary cells, the pattern of responses to SME and AVP were indistinguishable and the release provoked by rat SME could be accounted for virtually entirely by its vasopressin content. No stimulation of release was observed when the cells were exposed to a variety of biogenic amines. Addition of hydrocortisone to the perfusion buffer of two tumours resulted in a slow inhibition of both basal and stimulated ACTH and LPH release. These data demonstrate that human pituitary tumour tissue from patients with Cushing's disease and Nelson's syndrome can be studied in vitro and that such studies may contribute to a greater understanding of the aetiology of these diseases.

Corticotrophin releasing activity in extracts of the stalk median eminence of Brattleboro rats

The corticotrophin releasing (CRF) activity of stalk median eminence (SME) extracts from homozygous Brattleboro (DIhomo) rats was significantly less than that of the heterozygous (DIhet) rats which, in turn, was significantly less than normal (P less than 0.01). The bio- and immunoactivities of LH-releasing hormone (LH-RH) were not significantly different. No detectable immunoactive vasopressin was found in DIhomo SME and the vasopressin content of DIhet SME was less than normal. Chromatography of an extract of SME from 20 DIhomo rats on BioGel P2 resulted in a loss of CRF activity and the emergence of two regions of CRF activity: the peak at the void volume of the column and the later eluting peak which also had some LH-RH bioactivity but no immunoactivity. The third and major CRF peak found in normal SME, which co-elutes with vasopressin, was absent from the DIhomo chromatogram. The DIhomo LH-RH chromatogram was normal. When synthetic arginine-vasopressin was added to Brattleboro SME in amounts equivalent to those found in normal SME the CRF bioactivity was dramatically potentiated. It was concluded that Brattleboro rats have a specific defect for CRF at the hypothalamic level and this appears to be genetically linked to the synthesis of vasopressin which in itself is also essential for the stability and full expression of CRF bioactivity.

Using a cool spot to improve the thermal comfort of glassmakers

Glassmakers monitoring a rolled plate process suffered discomfort from the high temperature environment. This was caused by the radiant heat emitted by the furnaces and associated equipment surrounding the glassmakers' working area, combined with a high air temperature. The glassmakers are responsible for monitoring the glass rolling machine to ensure that the product is manufactured to specification, and to prevent the molten glass sticking to the rollers. This study improved their thermal comfort by the construction of a cool area. They were also brought nearer to the rolling machine. This, with the addition of a cooler environment, improved their monitoring performance. The cool spot was constructed using glass and aluminium radiant heat shields, air curtains and low velocity cooling air.

Chemical characterization of ectopic ACTH purified from a malignant thymic carcinoid tumor

ACTH was purified from thymic tumor associated with ectopic ACTH production by gel filtration and ion exchange chromatography. Amino acid composition and C- and N-terminal analyses indicated that this tumor ACTH was comprised of the 2-38 sequence of authentic pituitary ACTH. The observations suggest that the mode of cleavage of this tumor ACTH from its precursor is different from that of pituitary ACTH.