Observational study of admission and triage decisions for patients referred to a regional intensive care unit.

The objectives of this study were to identify factors associated with decisions concerning triage and admission to the intensive care unit and to describe the outcome of patients referred to intensive care unit for admission. The study was a single-centre, prospective, observational study. It was performed in the general intensive care unit of a tertiary regional hospital, over the period of February to June 2009. The patients were non-elective, acute medical in-patients. For 100 patients referred, only 36 were admitted to the intensive care unit. The remaining 64 were declined admission: nine were declined admission because they were assessed as too sick to benefit, 41 were declined admission because they were assessed as too well to benefit and 14 were deemed to potentially benefit from intensive care unit admission but were not admitted ('triage'). Patients most likely to receive triage decisions were medical in-patients who had expressed wishes about end-of-life care, who were functionally limited with co-morbid conditions affecting their performance status. Patients referred by Resident Medical Officers were also more likely to receive a triage decision. Age, gender Aboriginal and Torres Strait Islander status, diagnostic category and reason for referral did not impact on admission or triage decisions. Bed status in intensive care unit at the time of referral affected neither admission nor triage decisions. Hospital mortality in patients deemed too well to benefit from intensive care unit was 7.3%, suggesting that all patients referred for consideration of admission to intensive care unit should be classified as 'high risk'.

The late gestation increase in circulating ACTH and cortisol in the fetal sheep is suppressed by intracerebroventricular infusion of recombinant ovine leptin.

The obese gene product leptin, originally characterised as an adipocyte hormone coordinating the behavioural and neuroendocrine responses to starvation, is expressed in fetal adipocytes and placental trophoblast cells and is present in the fetal circulation. Concentrations of leptin in fetal blood correlate with fetal bodyweight and fat mass. In post-natal life, leptin conveys information about calorie intake and the state of adipose tissue energy stores, and plasma leptin levels are generally inversely correlated with hypothalamo-pituitary adrenal (HPA) activity. Late fetal life is characterised by increasing HPA activity that prepares the fetus for extrauterine life and initiates the endocrine cascade leading to parturition. We have investigated the hypothesis that leptin in the fetal circulation can inhibit the fetal HPA axis, thereby providing a mechanism by which the fetus can determine the fine timing of parturition as long as it is adequately nourished and growing appropriately. Here we show that a 5-day intracerebroventricular infusion of leptin to the sheep fetus in late gestation inhibits the pre-parturient rise in ACTH and cortisol concentrations, and that this seems to be a centrally mediated effect.

Increase in 15-hydroxyprostaglandin dehydrogenase activity in the ovine placentome at parturition and effect of oestrogen.

Type 1 NAD(+)-dependent 15-hydroxyprostaglandin dehydrogenase (PGDH) is the key enzyme for metabolism of active primary prostaglandins to inactive forms in gestational tissues. The present study examined the activity and immunolocalization of PGDH in the ovine placenta, fetal membranes and uterus over the latter half of pregnancy, and its potential regulation by oestradiol. Placenta, fetal membranes and myometrium were collected from sheep with known single insemination dates on days 70, 100 and 135 of gestation and in active labour demonstrated by electromyographic activity. In addition, chronically catheterized fetuses were infused with oestradiol (100 microgram kg(-1) per 24 h) (n = 5) or saline vehicle into the fetus from day 120 to day 125. PGDH activity measured in placental extracts remained constant from day 70 to day 135 of gestation, and then significantly (P < 0.05) increased by 300% in active labour. Immunoreactive PGDH was localized in the placentome at all stages and was present predominantly in the fetal component of the placentome in uninucleate, but not in binucleate, trophoblast cells. Similarly, in the fetal membranes PGDH immuno-reactivity was present in the uninucleate trophoblast but not in the binucleate cells of the chorion. PGDH immunostaining was also present in the endometrial luminal epithelium, in the smooth muscle of the myometrium, and the glandular epithelium of the cervix. Infusion of oestradiol into the fetal circulation from day 120 to day 125 of gestation had no effect on placental PGDH activity. Immunohistochemistry was used to localize oestrogen receptor alpha in intrauterine tissues to investigate further the failure of oestradiol to increase PGDH activity. Immunoreactive oestrogen receptor alpha was not present in the fetal component of the placenta, although it was expressed in adjacent maternal-derived cells. It is concluded that (1) PGDH activity increases in late gestation; (2) PGDH is expressed in uninucleate trophoblast cells in the ovine placenta and fetal membranes, and also in the maternal endometrial epithelium and stroma, myometrium and cervix; (3) oestrogen receptor alpha is not expressed in fetal cells in the placenta or fetal membranes; and (4) the increase in PGDH activity is not regulated by oestradiol administered to the fetus.

Involvement of matrix metalloproteinases 2 and 9, tissue inhibitor of metalloproteinases and apoptosis in tissue remodelling in the sheep placenta.

Placental growth and development is crucial for successful pregnancy. The aim of this study was to characterize the activity and localization of the matrix metalloproteinase 2 (MMP-2) and MMP-9, which are capable of degrading basement membrane collagen (predominantly collagen type IV), and their endogenous tissue inhibitor of matrix metalloproteinases (TIMPs), in amniotic fluid and in the developing ovine placenta. Cell deletion by apoptosis during placental development was also examined. Zymography with gelatin as substrate indicated that MMP-2 (72 kDa gelatinase A; predominantly latent form) was present in increasing amounts in amniotic fluid from day 70 of gestation to labour (days 140-145), and MMP-9 (92 kDa gelatinase B; predominantly latent form) was detectable from day 125 to labour; there was no increase in MMP-2 or -9 in labour. A broad range of TIMPs was detected in amniotic fluid; the molecular masses corresponded to TIMP-1, -2 and -3. Immunohistochemical techniques localized MMP-2, MMP-9 and TIMP-3 in the sheep placenta, predominantly in the trophoblast layer in uninucleate, but not binucleate, cells. However, MMP-2 and -9 activated proteins in placental homogenates were low throughout pregnancy. Apoptosis was identified by morphological criteria and also by TdT-mediated dUTP nick end labelling. Apoptosis was present in discrete regions in the placenta, predominantly in trophoblast cells near the tips and the basal regions of the fetomaternal interdigitations. During pregnancy the sheep placenta becomes more complex and the area of the fetomaternal interface increases. MMP-2 and -9 are likely to be involved in breaking down basement membranes to allow cell migration during this process. It is suggested that digestion of supporting extracellular matrix may trigger apoptosis and in some way increase the branching pattern in the villi.

Secretion of tissue inhibitors of matrix metalloproteinases by human fetal membranes, decidua and placenta at parturition.

At parturition, breakdown of extracellular matrix in the fetal membranes may play a part in the rupture of the membranes and in the aetiology of premature rupture, in addition to having a regulatory role in the cell-cell interactions and signalling at the feto-maternal interface to stimulate myometrial contractility. The matrix metalloproteinases (MMPs) are important enzymes for the breakdown of extracellular matrix and their activity is regulated by a family of endogenous inhibitors, the tissue inhibitors of matrix metalloproteinases (TIMPs). At parturition, alteration in the balance between MMPs and TIMPs may mediate this extracellular matrix breakdown during rupture of fetal membranes. The aims of this study were to determine if the intrauterine secretion of TIMPs changes at labour, and to characterise their cellular sources. A broad range of TIMP activities (27-30 kDa, 24 kDa and 21 kDa) were detected by reverse zymography in term amniotic fluid. There was a significant (P<0.05) decrease in the amount of TIMPs in amniotic fluid and their release with the onset of labour. The TIMPs were characterised by immunoblot as TIMPs-1, -2, -3 and -4. High levels of TIMPs were secreted by explants of chorio-decidua, decidua parietalis and placenta, with less being released by amnion. Immunolocalisation studies revealed a specific distribution pattern for each of the TIMP isoforms. Trophoblast cells of chorion laeve, decidua parietalis and placental syncytiotrophoblast demonstrated specific immunoreactivity for all four isoforms. TIMPs were also found bound to selective regions of extracellular matrix. The decrease in TIMPs during labour may permit increased breakdown of extracellular matrix in the fetal membranes and decidua at parturition, thus altering cell signalling at the feto-maternal interface and facilitating membrane rupture.

Secretion of matrix metalloproteinase-2, matrix metalloproteinase-9 and tissue inhibitor of metalloproteinases into the intrauterine compartments during early pregnancy.

Matrix metalloproteinases (MMPs) are important enzymes in tissue remodelling, a key event for the development of the fetal membranes and placenta and establishing the feto-maternal interface during early pregnancy. This study has examined the secretion of the gelatinases, MMP-2 (72 kDa) and MMP-9 (92 kDa), and the endogenous tissue inhibitors of metalloproteinases (TIMPs) into extra-embryonic coelomic and amniotic fluids, the two principal intra-uterine compartments of the first trimester, and compared them to amniotic fluid collected later in gestation. In extra-embryonic coelomic fluid, gelatin zymography demonstrated that MMP-2 (72 kDa) was the predominant gelatinase, with some MMP-9 present. A broad range of TIMPs corresponding to TIMP-1 and TIMP-2, glycosylated and unglycosylated TIMP-3 and TIMP-4 was detected in this compartment by reverse zymography and immunoblot analyses. There was little gelatinase or TIMP activity in amniotic fluid in the first trimester. In amniotic fluid from the second trimester after fusion of the membranes obliterating the extra-embryonic coelom, and at term elective caesarean section, MMP-2 is the predominant gelatinase present, with a broad spectrum of TIMPs. These findings demonstrate that predominantly MMP-2 and also MMP-9, regulated by a range of TIMPs, are involved in intra-uterine tissue remodelling during the establishment of pregnancy.

Neuroendocrine regulation of pituitary-adrenal function during fetal life.

During late gestation there is a rise in the concentration of corticosteroids in the fetal circulation that is essential for the coordinated maturation of many fetal organ systems and is a key component in the endocrine pathway leading to the onset of birth. Fetal plasma concentrations of adrenocorticotrophin (ACTH) increase during late gestation and this rise precedes the increase in plasma corticosteroids. Paradoxically, ACTH and cortisol concentrations increase concomitantly even though cortisol would normally be expected to exert negative feedback effects to inhibit pituitary ACTH secretion. Elucidating the neuroendocrine signals that cause the increase in fetal ACTH, despite the elevated concentrations of cortisol at this time, will therefore provide vital clues as to the trigger for fetal organ maturation and birth. This article describes the normal ontogeny of the hypothalamo-pituitary-adrenal axis, discusses the neuroendocrine signals that trigger the increase in fetal ACTH secretion and provides potential explanations for the concomitant rise in ACTH and cortisol.

Adrenocorticotrophin and luteinizing hormone responses to N-methyl-D-aspartate during fetal development in sheep.

The hypothalamic mechanisms which underlie the development of the fetal neuroendocrine system are unclear. However, in adult animals neuroactive amino-acids, particularly those acting at the N-methyl-D-aspartate (NMDA) receptor, have been shown to be important transmitters involved in the neuroendocrine regulation of the anterior pituitary gland. In this study we have investigated the potential role of NMDA in the neuroendocrine regulation of fetal pituitary function, by examining the ontogeny of LH and ACTH responses to NMDA during fetal development in sheep. Catheterized fetal sheep were injected with 3 intravenous doses of NMDA (1, 2 and 4 mg/kg; estimated fetal body weight) and saline vehicle on consecutive days between days 110-115, 120-125 and 135-140 gestation (term = 145 days). At each gestational age fetuses also received a pituitary challenge test consisting of CRF (0.4 mu g/kg), AVP (80 ng/kg) and GnRH (125 ng/kg). NMDA caused a significant dose-related increase in ACTH at day 120-125 (P<0.02) and day 135-140 gestation (P<0.001). NMDA had no effect on ACTH secretion at day 110-115. The ACTH response to the highest does of NMDA (4 mg/kg) increased with advancing gestational age, in contrast to the ACTH response to CRF+AVP which was the same at all ages. NMDA caused a significant increase in LH secretion at all gestational ages with the greatest response observed at the latest gestational age studied (day 135-140). A similar increase in LH response to the GnRH challenge was observed late in gestation. Pretreatment of fetuses with the competitive NMDA antagonist CGP37849 (1 mg/kg) abolished the LH and ACTH responses to an intravenous injection of NMDA (4 mg/kg) given 5 min later. These data show that activation of NMDA receptors during fetal development elicits the secretion of ACTH and LH and demonstrate that NMDA receptors are functionally coupled to the neuroendocrine pathways regulating these two hormones during fetal life. The dramatic increase in ACTH response to NMDA during the final days before birth occurs at a time of high adrenocortical activity and suggests an important functional role for these receptors at this time.

Neuropeptide-Y stimulates pituitary-adrenal activity in fetal and adult sheep.

Corticotrophin-releasing factor (CRF) and arginine vasopressin (AVP) are the primary neuropeptides regulating the secretion of ACTH from the anterior pituitary gland during fetal and adult life. However, a number of other neuropeptides including neuropeptide-Y (NPY) appear to modulate the activity of this system. The potential role of NPY in the regulation of pituitary-adrenal function was examined in fetal and adult sheep. Administration of NPY (6.5 micrograms) as a bolus injection into the third cerebral ventricle of adult ewes elicited a significant (P < 0.05) increase in plasma concentrations of ACTH. In fetal sheep at day 125 gestation (term = 145 days) a five-fold higher dose (30 micrograms) of NPY injected into the lateral cerebral ventricles also caused a significant increase in plasma concentrations of ACTH. The potential of NPY to influence ACTH secretion directly from the pituitary gland was investigated using primary cultures of fetal (day 130 gestation) and adult pituitary cells. CRF (10(-10)-10(-7) M) caused a significant (P < 0.01) dose-related increase in ACTH secretion from both fetal and adult pituitary cells. Furthermore, the secretion of ACTH from adult cells was significantly greater (P < 0.05) than that from fetal cells. NPY (10(-10)-10(-7) M) had no effect on basal or CRF-stimulated ACTH secretion from fetal or adult pituitary cells. Pre-incubation of pituitary cells with cortisol (10(-9) and 10(-7) M) for three days significantly inhibited CRF-stimulated ACTH secretion but had no effect on basal ACTH release. The simultaneous addition of NPY did not alter the ability of cortisol to inhibit CRF-stimulated ACTH secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of alfentanil sedation anesthesia with the Dornier HM3 lithotripter.

Our results with the combination anesthetic technique of midazolam-alfentanil during elective outpatient extracorporeal shock wave lithotripsy on the Dornier HM3 (N = 79) were compared with those of epidural anesthesia in the same setting (N = 81). The mean anesthesia time and recovery room time were significantly shorter (72.85 v 113.58 minutes and 115.0 v 159.20 minutes, respectively) with the combination technique. No procedures in the alfentanil group had to be discontinued because of patient discomfort. Side effects with alfentanil were minimal, and oxygen saturation remained above 90% for all patients. Combination midazolam-alfentanil anesthesia is safe and allows the urologist to treat renal and ureteral calculi effectively and efficiently without using general or regional anesthesia.

Effects of decreasing exogenous GnRH pulse frequency on FSH and inhibin secretion in men with idiopathic hypogonadotropic hypogonadism.

The potential importance of GnRH pulse frequency modulation and steroid or inhibin negative feedback in the selective control of pituitary FSH secretion was investigated in 5 adult men with idiopathic hypogonadotropic hypogonadism in whom plasma testosterone has been previously normalized by pulsatile GnRH therapy. The effects of decreasing frequency of pulsatile iv GnRH administration from 2- to 4-hourly for 7 days were examined at constant GnRH bolus dose or constant daily dose and also with interrupted gonadal steroid feedback using a combination of an anti-androgen (flutamide 250 mg t.i.d.) and an aromatase inhibitor (aminogluthetimide 125 mg b.d.) orally for a further 7 days. Slowing GnRH pulse frequency from 2- to 4-hourly did not alter mean plasma FSH at constant bolus dose or constant total daily doses of GnRH. In two subjects with subnormal but not in another two with normal testicular volumes, FSH rise was observed when the 4-hourly GnRH pulse frequency was combined with the interruption of steroid feedback. These results are not compatible with a major role for GnRH pulse frequency modulation in the regulation of pituitary FSH secretion in the presence of normal gonadal steroid feedback. Irrespective of FSH concentrations, plasma inhibin immunoactivity did not change significantly with the alteration in GnRH pulse frequency. The role of inhibin in the control of FSH therefore remains undefined in men.

Characterization of a Legionella pneumophila gene encoding a lipoprotein antigen.

A prominent 19 kDa surface antigen of Legionella pneumophila, cloned in Escherichia coli, was found to be intimately associated with peptidoglycan. The DNA region encoding this antigen was mapped on an 11.9 kb plasmid by means of deletion analysis and transposon mutagenesis. PhoA+ gene fusions, gene-rated by TnphoA insertions into this region, confirmed the presence of a gene encoding a secreted protein. PhoA+ transposon insertions were also associated with loss of the 19 kDa antigen in immunoassays using a monoclonal antibody (mAb1E9) and the replacement of the 19 kDa antigen with larger fusion proteins in immunoblots using Legionella immune serum. A 1540bp PstI fragment carrying the gene was sequenced, and the open reading frame encoding the antigen was identified. The gene encodes a polypeptide 176 amino acid residues long and 18913Da in size. The presence of a signal sequence of 22 amino acids with a consensus sequence for cleavage by signal peptidase II indicates that the antigen is a lipoprotein, and striking similarity with peptidoglycan-associated lipoproteins (PALs) from E. coli (51% amino acid homology) and Haemophilus influenzae (55% homology) is noted. We conclude that the 19kDa antigen of L. pneumophila is the structural equivalent of the PAL found in other Gram-negative species and suggest that its post-translational acylation may explain its potency as an immunogen.

N-Methyl-DL-Aspartate Receptor Antagonism by D-2-Amino-5-Phosphonovaleric Acid Delays Onset of Puberty in the Female Rat.

Abstract To investigate the possible role of N-methyl-DL-aspartate (NMDA) receptor activation in the initiation of puberty, we examined the effects of the selective competitive antagonist 2-amino-5-phosphonovaleric acid (AP5) on the timing of vaginal opening. Paired and weight-matched litter mates of immature female rats were implanted with osmotic minipumps for the intracerebroventricular infusion of DL- or D-AP5 or artificial cerebrospinal fluid from 27 to 30 days of age for 14 days. Each animal was weighed and examined daily for vaginal opening as the indicator of first oestrous. Infusion of 20 or 40 mM DL-AP5 beginning on Day 30 failed to delay vaginal opening. Administration 50mM of the single enantiomer D-AP5 beginning on Day 27 significantly delayed the age of vaginal opening to 40.6+/-1.1 (mean +/- SEM) days compared to the cerebrospinal fluid-infused controls (36.5 +/- 0.6 days). Blockade of NMDA receptors in the D-AP5-treated animals was confirmed on Day 32 by the suppression of luteinizing hormone response to intravenous NMDA (20 mg/kg) while the response to exogenous luteinizing hormone-releasing hormone (50 ng/kg) remained intact. AP5-treated animals had a slower rate of growth (3.1 +/- 0.2 g/day) compared to controls (4.2 +/- 0.2 g/day). However, a similar degree of growth retardation produced by a 75% restricted diet in untreated juvenile animals did not delay vaginal opening. This suggests that the slower growth rate in the D-AP5-treated animals could not account for the delayed onset of puberty. In conclusion, these data suggest that blockade of central NMDA receptors inhibits excitatory mechanisms which may be important in the control of pubertal onset in the female rat.

Effects of incidental pictorial and verbal adjuncts on text learning.

In this study, college students read and studied texts on historical figures in psychology, which were supplemented by drawings and/or brief biographies of these persons. In Experiment 1, a 2 x 2 between-groups design was conducted in which students received one adjunct with each text, both adjuncts, or neither. In Experiment 2, a single group of students received a within-subjects manipulation of the same adjunct conditions. In the between-groups comparison, students receiving biographies learned less of the target text passages, with the group receiving illustrations and biographies performing least accurately. In the within-subject conditions, texts accompanied by an illustration were better learned, with these students doing best on the text with both picture and biography. The results suggest that adjuncts may emphasize some texts, at the expense of learning from the other texts, but that too much adjunct material interferes with the learning of the target passages.