Melanocortin receptor accessory proteins in adrenal gland physiology and beyond.

The melanocortin receptor (MCR) family consists of five G-protein-coupled receptors (MC1R-MC5R) with diverse physiological roles. MC1R controls pigmentation, MC2R is a critical component of the hypothalamic-pituitary-adrenal axis, MC3R and MC4R have a vital role in energy homeostasis and MC5R is involved in exocrine function. The melanocortin receptor accessory protein (MRAP) and its paralogue MRAP2 are small single-pass transmembrane proteins that have been shown to regulate MCR expression and function. In the adrenal gland, MRAP is an essential accessory factor for the functional expression of the MC2R/ACTH receptor. The importance of MRAP in adrenal gland physiology is demonstrated by the clinical condition familial glucocorticoid deficiency, where inactivating MRAP mutations account for ∼20% of cases. MRAP is highly expressed in both the zona fasciculata and the undifferentiated zone. Expression in the undifferentiated zone suggests that MRAP could also be important in adrenal cell differentiation and/or maintenance. In contrast, the role of adrenal MRAP2, which is highly expressed in the foetal gland, is unclear. The expression of MRAPs outside the adrenal gland is suggestive of a wider physiological purpose, beyond MC2R-mediated adrenal steroidogenesis. In vitro, MRAPs have been shown to reduce surface expression and signalling of all the other MCRs (MC1,3,4,5R). MRAP2 is predominantly expressed in the hypothalamus, a site that also expresses a high level of MC3R and MC4R. This raises the intriguing possibility of a CNS role for the MRAPs.

Factors affecting storage stability of various commercial phytase sources.

A 360-d study was performed to evaluate the effects of different environmental conditions on storage stability of exogenous phytases. Coated and uncoated products from 3 phytase sources [Ronozyme P (DSM Nutritional Products, Basel, Switzerland), OptiPhos (Phytex LLC, Sheridan, IN), and Phyzyme (Danisco Animal Nutrition, Marlborough, UK)] were stored as pure forms, in a vitamin premix, or in a vitamin and trace mineral (VTM) premix. Pure products were stored at -18, 5, 23, and 37°C (75% humidity). Premixes were stored at 23 and 37°C. Sampling was performed on d 0, 30, 60, 90, 120, 180, 270, and 360. Sampling of the pure products stored at -18 (lack of sample) and 5°C (because of mold growth) was discontinued after d 120. Stability was reported as the residual phytase activity (% of initial) at each sampling point. For the stability of the pure forms, all interactive and main effects of the phytase product, coating, time, and storage temperature were significant (P < 0.01), except for the time × coating interaction. When stored at 23°C or less, pure phytases retained at least 91, 85, 78, and 71% of their initial phytase activity at 30, 60, 90, and 120 d of storage, respectively. However, storing pure products at 37°C reduced (P < 0.01) phytase stability, with OptiPhos retaining the most (P < 0.01) activity. Coating mitigated (P < 0.01) the negative effects of high storage temperature for Ronozyme and OptiPhos (from d 90 onward), but not for Phyzyme. For the stability of phytase in different forms of storage, all interactive and main effects of phytase product, form, coating, time, and temperature of storage were significant (P < 0.01). When stored at room temperature (23°C), retained phytase activities for most the phytase sources were more than 85, 73, and 60% of the initial activity up to 180 d when stored as pure products, vitamin premixes, or VTM premixes, respectively. When stored at 37°C, pure phytase products had greater (P < 0.01) retention of initial phytase activity than when phytases were mixed with the vitamin or VTM premixes. Coated phytases stored in any form had greater (P < 0.01) activity retention than the uncoated phytases at all sampling periods. Results indicate that storage stability of commercially available phytases is affected by duration of storage, temperature, product form, coating, and phytase source. Pure products held at 23°C or less were the most stable. In premixes, longer storage times and higher temperatures reduced phytase activity, but coating mitigated some of these negative effects.

Cerebellin1 is a novel orexigenic peptide.

AIM: Cerebellin1 (Cbln1) is highly expressed in the hypothalamus, a region of the brain involved in appetite regulation. However, the effects of Cbn1 on food intake are not known. The present study aimed to investigate the effect of Cbln1 on appetite regulation in rats. METHODS: We determined the effect of (i) intracerebroventricular (ICV) injection of Cbln1 on food intake, behaviour and plasma pituitary hormone levels in male Wistar rats; (ii) Cbln1 on the release of hypothalamic neuropeptides known to modulate food intake from hypothalamic explants and (iii) fasting on hypothalamic Cbln1 mRNA expression. RESULTS: (i) ICV administration of Cbln1 significantly increased food intake in rats and caused no adverse behaviours. ICV administration of Cbln1 significantly reduced plasma thyroid stimulating hormone (TSH) levels 10 min postinjection in rats. (ii) Cbln1 significantly increased the release of neuropeptide Y (NPY) from hypothalamic explants. (iii) Cbln1 mRNA expression levels were increased in the ventromedial nucleus of the hypothalamus in fasted rats. CONCLUSIONS: These data suggest that Cbln1 is a novel orexigenic peptide, which may mediate its effects via hypothalamic NPY.

Management of blood loss in periacetabular osteotomy.

The aim of this study was to determine the efficacy and cost-effectiveness of the use of predonation of autologous blood for the periacetabular osteotomy. We carried out a retrospective single surgeon series study looking at patient demographics, intraoperative blood loss, volume of red cells returned (by cell salvage and allogenic/autologous transfusion), and comparing pre- and postoperative haemoglobin levels in those that predonated and those that did not. One hundred and twenty-two procedures were performed on 107 patients between 1996 and 2005. An initial audit (22 procedures) revealed high wastage (45% returned) of allogenic blood. A predonation protocol was initiated and subsequently 100 procedures in 91 patients were performed. In 82 procedures, the patients were eligible for predonation. A total of 226 units of autologous blood were predonated and 92% was used. Only 13 of these patients (16%) required additional allogenic transfusion for unforeseen excessive blood loss intraoperatively. A set protocol for predonation reduces the need for allogenic transfusion and involves minimal wastage. In a procedure which has significant blood loss, we suggest that preoperative autologous donation is a safe and cost effective method of managing blood loss.

Folic acid use in pregnancy and embryo selection.

OBJECTIVE: Folic acid supplement use is recommended in pregnancy to reduce the risk of neural tube defect but concerns have been raised that increasing folic acid intake may select for embryos with genotypes that increase disease risk in the offspring. Our aim was to test for this effect. DESIGN: Observational prospective cohort study. SETTING: Aberdeen Maternity Hospital. POPULATION OR SAMPLE: Women born before the introduction of folic acid advice (1970-80) and carrying singleton pregnancies (n = 1234) and their offspring (n = 1083) born after (2001-03). METHODS: We measured the genotype (MTHFR C677T and A1298C, MTR A2756G, MTRR A66G and TCN G776C) of mothers and their offspring, maternal supplement intake, intake of folate and vitamin B12 from natural foods and maternal blood folate and B12 status at 19 weeks of gestation. MAIN OUTCOME MEASURES: B vitamin related genotype of the offspring. RESULTS: There were no significant differences in any of the five genotype frequencies between mothers and their babies. There was no deviation from Hardy-Weinberg equilibrium in either generation and no change in the frequency of doubly homozygous MTHFR variants (677 TT/1298 CC). The genotype of the offspring was not related to maternal periconceptual supplement use, folate intake from foods or plasma and red cell folate measured at 19 weeks of gestation. CONCLUSIONS: We found no evidence to support the concern that folic acid fortification or supplement use in pregnancy results in selection of deleterious genotypes.

Predicting the pathway to wind pollination: heritabilities and genetic correlations of inflorescence traits associated with wind pollination in Schiedea salicaria (Caryophyllaceae).

The transition from biotic to abiotic pollination was investigated using Schiedea, a genus exhibiting a remarkable diversity of inflorescence architecture associated with pollination biology. Heritabilities and genetic correlations of inflorescence traits were estimated in gynodioecious Schiedea salicaria (Caryophyllaceae), a species that has likely undergone a recent transition to wind-pollination. Using a partial diallel crossing design, significant narrow-sense heritabilities were detected for inflorescence condensation (h2 = 0.56 to 0.68 in the two sexes) and other traits related to the extent of wind pollination in Schiedea species. Heritabilities were generally higher in hermaphrodites than in females. Strong genetic correlations may constrain the evolution of some inflorescence traits that facilitate wind pollination, such as simultaneous shortening of inflorescence length and elongation of the subtending internode. The presence of significant narrow-sense heritabilities for traits associated with wind pollination suggests, however, that selection for more effective wind pollination in the windy, pollinator-limited environments where S. salicaria grows could lead to the evolution of the highly condensed inflorescences characteristic of other wind-pollinated species of Schiedea.

Arthrofibrosis following total knee replacement; does therapeutic warfarin make a difference?

Arthrofibrosis following total knee replacement (TKR) is a relatively common complication which results in a reduction in knee range of movement and patient dissatisfaction. A retrospective study examined the relationship between anticoagulation with therapeutic warfarin and rates of arthrofibrosis following TKR. Arthrofibrosis was defined as less than 80 degrees of knee flexion 6-8 weeks post-TKR. Patients were warfarinised if they had a history of thrombophilic tendencies or medical conditions necessitating anti-coagulation, rather than as routine thromboprophylaxis. All other patients received thromboprophylaxis using low molecular weight heparin. A total of 728 patients underwent 874 primary TKR between 1993 and 2002 in one centre, performed by four surgeons. Mean age was 68 years (range 48-89 years) and there were 483 female and 391 male knees. Eighty cases were warfarinised post-operatively (53 female, 27 male). Overall, 83 of 874 TKRs (9%) had arthrofibrosis (57 female, 26 male) requiring manipulation under anaesthetic (MUA). In the warfarinised group, 21 knees (26%) had an MUA (15 female, 6 male). This compared to 62 cases (8%) requiring MUA in the non-warfarinised group (42 female, 20 male). There was a statistically significant difference on Fisher's exact testing (P<0.0001) between groups. Following MUA, knee flexion improved in 95% cases to a minimum 95 degrees but 8 cases had a fixed flexion deformity of 5-10 degrees . In conclusion, therapeutic warfarinisation post-TKR leads to a statistically greater chance of the patient developing arthrofibrosis compared to prophylactic low molecular weight heparin and that patients should be counseled appropriately.

Long-term renoprotection by perindopril or nifedipine in non-hypertensive patients with Type 2 diabetes and microalbuminuria.

AIMS: To assess the efficacy of an angiotensin converting enzyme (ACE) inhibitor (perindopril), a dihydropyridine calcium channel blocker (sustained release nifedipine) and placebo in preventing the progression of albuminuria and decline in glomerular filtration rate (GFR) in patients with Type 2 diabetes and microalbuminaria. METHODS: A prospective, randomized, open, blinded end point study of 77 patients allocated to three treatment groups (23 perindopril, 27 nifedipine, 27 placebo). Drug doses were adjusted to achieve a decrease in diastolic blood pressure (DBP) of 5 mmHg in the first 3 months and additional therapy was given if hypertension developed (supine DBP > 90 mmHg and/or systolic blood pressure (SBP) > 140 mmHg if < or = 40 years; supine DBP > 90 mmHg and/or SBP > 160 mmHg if > 40 years). Median follow-up was 66 months, with 37 patients being followed for at least 6 years. RESULTS: Blood pressure remained within the non-hypertensive range in 83% of perindopril-, 95% of nifedipine- and 30% of placebo-treated patients (P < 0.01). In the first 12 months albumin excretion rate (AER) decreased by 47% only in the perindopril group (P = 0.04). From 12 to 72 months, AER gradients increased by 27% per year only in the placebo group (P < 0.01). After 6 years, macroalbuminuria had developed in 7/15 placebo compared with 2/11 in perindopril and 1/11 nifedipine-treated patients (P = 0.05). GFR did not change in the first 12 months, but thereafter the median GFR gradient (ml/min/1.73 m(2) per year) was -2.4 (P < 0.01) for perindopril-, -1.3 (P = 0.26) for nifedipine- and -4.2 (P = 0.01) for placebo-treated patients. The rate of decline in GFR for the study group as a whole from 12 months to the end of follow-up correlated negatively with mean arterial pressure (MAP) (r = -0.38, P < 0.01). During a 3-month treatment pause in 29 patients AER tended to increase only in the perindopril group (P < 0.07). CONCLUSIONS: Long-term control of blood pressure with perindopril or nifedipine stabilizes AER and attenuates GFR decline in proportion to MAP in non-hypertensive patients with Type 2 diabetes and microalbuminuria.

Reproductive isolation and hybrid pollen disadvantage in Ipomopsis.

One cause of reproductive isolation is gamete competition, in which conspecific pollen has an advantage over heterospecific pollen in siring seeds, thereby decreasing the formation of F1 hybrids. Analogous pollen interactions between hybrid pollen and conspecific pollen can contribute to post-zygotic isolation. The herbaceous plants Ipomopsis aggregata and I. tenuituba frequently hybridize in nature. Hand-pollination of I. aggregata with pollen from F1 or F2 hybrids produced as many seeds as hand-pollination with conspecific pollen, suggesting equal pollen viability. However, when mixed pollen loads with 50% conspecific pollen and 50% hybrid pollen were applied to I. aggregata stigmas, fewer than half of the seeds had hybrid sires. Such pollen mixtures are frequently received if plants of the two species and F1 and F2 hybrids are intermixed, suggesting that this advantage of conspecific over hybrid pollen reduces backcrossing and contributes to reproductive isolation.

Differential effects of once-daily antihypertensive drugs on blood pressure, left ventricular mass and sympathetic activity: Nifedipine-GITS versus felodipine-ER versus enalapril.

BACKGROUND: Recent meta-analyses suggest that once-daily dihydropyridines and angiotensin-converting enzyme inhibitors cause similar decreases in left ventricular (LV) mass for comparable decreases in blood pressure (BP). However, some dihydropyridines, such as felodipine-extended release (ER), still increase sympathetic activity and may, therefore, be less effective in decreasing LV mass. OBJECTIVES: To evaluate the effects of long term antihypertensive treatment with nifedipine-gastrointestinal therapeutic system (GITS) and felodipine-ER compared with enalapril on LV mass relative to the extent of BP control (assessed by 24 h ambulatory BP monitoring) and sympathetic activity (assessed by plasma catecholamine concentrations). PATIENTS AND METHODS: Enalapril was started at 10 mg/day, felodipine-ER at 5 mg/day and nifedipine-GITS at 30 mg/day, all once daily. Doses were increased to 20 mg/day, 10 mg/day or 60 mg/day, respectively, if the office BP remained 160/90 mmHg or greater at the end of the dosing interval. Evaluable echocardiograms were obtained for 116 patients at the end of the study (30 weeks of treatment). RESULTS: On 24 h ambulatory BP monitoring, nifedipine-GITS caused a consistent decrease in BP throughout the 24 h dosing interval, whereas felodipine-ER caused a more marked fall in BP during the day, and enalapril's effects diminished during the night and had disappeared by the morning. Only felodipine-ER significantly increased supine and standing plasma noradrenaline by more than 50% similarly after six, 18, and 30 weeks of treatment. In BP responders (decrease in systolic BP 10 mmHg or greater), enalapril and nifedipine-GITS caused clear decreases in LV mass by 12 to 16 g/m2, whereas felodipine-ER was less effective (decrease by only 6 g/m2, P<0.01 versus enalapril). CONCLUSIONS: Once-daily dihydropyridines should not be regarded as one homogeneous class and, compared with felodipine-ER, nifedipine-GITS exhibits a better profile regarding 24 h BP control, sympathetic activation and regression of LV mass.

Long-term comparison between perindopril and nifedipine in normotensive patients with type 1 diabetes and microalbuminuria.

The aim of this study is to compare the efficacy of an angiotensin-converting enzyme inhibitor with a dihydropyridine calcium channel blocker in preventing progression to macroalbuminuria and/or a decline in renal function in normotensive patients with type 1 diabetes and microalbuminuria. Forty-two patients were randomized to treatment with either perindopril, slow-release nifedipine, or placebo. In the first 3 months, drug dosage was titrated to achieve a decrease in diastolic blood pressure of at least 5 mm HG: Thirty-three patients had a minimum of 24 months' data, and 25 patients were followed up beyond 36 months (mean, 67 +/- 4 months). Patients were studied every 3 months and at the end of the treatment period; those who remained normotensive discontinued therapy and were followed up for an additional 3 months. Baseline geometric mean albumin excretion rates (AERs) were as follows: perindopril, 66 microg/min; nifedipine, 59 microg/min; and placebo, 66 microg/min. During the first 3 years, 7 of the perindopril-treated but none of the placebo or nifedipine-treated patients reverted to normoalbuminuria (P < 0.01). Median AERs at 3 years of treatment in each group were 23 microg/min for perindopril, 122 microg/min for nifedipine, and 112 microg/min for placebo patients (P < 0.01). In patients with more than 3 years' follow-up, median AERs decreased by 45% in the first year and then stabilized in the perindopril group, but increased by 17.6% in the nifedipine group and 27.6% in the placebo group (P < 0.03) in the first year, then increased progressively. In these same patients, there was a significant decline in glomerular filtration rate in the nifedipine group (-7.8 +/- 1.8 mL/min/1.73 m(2)/y), but not in the other two groups (perindopril, -1.0 +/- 1.2 mL/min/1.73 m(2)/y; placebo, -1.3 +/- 1.1 mL/min/1.73 m(2)/y; P = 0.004). At the end of the study, cessation of treatment for 3 months was associated with a doubling of AERs in the perindopril-treated group, but no change in the other two groups (P < 0.001). In conclusion, long-term perindopril therapy is more effective than nifedipine or placebo in delaying the progression of diabetic nephropathy and reducing AER to the normoalbuminuric range (<20 microg/min) in normotensive patients with type 1 diabetes and microalbuminuria.

Cocaine use and the mid-latency auditory evoked responses.

To examine the effects of chronic cocaine use on the mid-latency auditory evoked responses (MLAERs), we recorded the evoked responses of 15 cocaine-dependent subjects and 13 age-matched healthy control subjects. Two evoked response paradigms were used: a trains paradigm with four different inter-stimulus intervals (ISIs) and a paired-click paradigm. Our data suggest that cocaine-dependent subjects generate smaller P50 components when long ISIs are used with multiple repetitions (in the trains paradigm). In a single repetition paradigm (paired clicks), a significant decrease in the ability to attenuate the N100 component was seen in the cocaine-dependent subjects.

Cloning, localisation and functional expression of a novel human, cerebellum specific, two pore domain potassium channel.

We have isolated, by degenerate PCR, a complementary DNA encoding a novel two pore domain potassium channel. This is the 7th functional member of the human tandem pore domain potassium channel family to be reported. It has an open reading frame of 1.125 kb and encodes a 374 amino acid protein which shows 62% identity to the human TASK-1 gene: identity to other human members of the family is 31-35% at the amino acid level. We believe this gene to be human TASK-3, the ortholog of the recently reported rat TASK-3 gene: amino acid identity between the two is 74%. 'Taqman' mRNA analysis demonstrated a very specific tissue distribution pattern, showing human TASK-3 mRNA to be localised largely in the cerebellum, in contrast rat TASK-3 was reported to be widely distributed. We have shown by radiation hybrid mapping that human TASK-3 can be assigned to chromosome 8q24.3. Human TASK-3 was demonstrated to endow Xenopus oocytes with a negative resting membrane potential through the presence of a large K(+) selective conductance. TASK-3 is inhibited by extracellular acidosis with a mid-point of inhibition around pH 6. 5, supporting the predictions from the sequence data that this is a third human TASK (TWIK-related acid sensitive K(+) channel) gene.

The effect of timing of intravenous muscle relaxant on the quality of double-contrast barium enema.

AIM: To determine whether the timing of buscopan administration during double-contrast barium enema examination (DCBE) affects diagnostic quality. MATERIALS AND METHODS: In a prospective setting, 100 consecutive adult out-patients referred for DCBE received 20 mg buscopan (hyoscine-N-butylbromide) intravenously, either before infusion of barium suspension (Group A) or after barium infusion and gas insufflation (Group B). A subjective assessment of ease of contrast medium infusion was made at the time of examination and the films subsequently analysed by two radiologists unaware of the mode of relaxant administration, who noted the quality of mucosal coating and made subjective and objective measurements of segmental distension. RESULTS: There was no significant difference in screening times, infusion difficulty or colonic contrast medium coating between the two groups. Subjective assessment of distension of the caecum, ascending colon, transverse colon and rectum were not significantly different. Patients receiving intravenous relaxant after barium and gas infusion had less subjective descending (P = 0. 05) and sigmoid (P = 0.04) colon distension, but there was no significant difference with respect to maximal bowel diameter in any of the segments measured. CONCLUSION: The timing of intravenous administration during DCBE is likely to have no significant effect on the diagnostic quality of the study.

New York State universal newborn hearing screening demonstration project: inpatient outcome measures.

OBJECTIVE: To evaluate the feasibility of universal newborn hearing screening by examining inpatient outcome measures from 8 hospitals located in geographically diverse areas of New York State over a 3-yr period. DESIGN: Funding was provided by the New York State Department of Health to implement predischarge hearing screening programs in the neonatal intensive care units (NICUs) and well-baby nurseries (WBNs) of eight hospitals. Various screening protocols including transient evoked otoacoustic emissions alone or in combination with conventional auditory brain stem response or screening auditory brain stem response were implemented by each site. Measured outcomes included rate of misses, refusals, and fails. Results were analyzed as a function of year of operation, nursery type, and geographic location. RESULTS: Six out of eight hospitals successfully implemented universal hearing screening during the first year, and the remaining 2 hospitals implemented programs during the second year of the project. Over a period of 3 yr, 69,761 newborns were screened at the eight hospitals representing 96.9% of all live births. The overall fail rate (4.04%) combined with the miss rate (2.61%) resulted in 6.63% of infants referred for outpatient follow-up. Mean data indicated that inpatient outcome measures improved with year of operation, with most individual hospitals also showing improvements. Both fail and miss rates were higher in the NICU than in the WBN and for hospitals located in New York City than in other regions of the state. CONCLUSIONS: Inpatient outcome measures of a universal newborn hearing screening project, which involved multiple centers across geographically diverse regions of New York State, were acceptable in terms of successfully screening a high percentage of live births and attaining low refer rates for outpatient screening. This study adds to the growing body of literature supporting the feasibility of screening all newborns before hospital discharge.

Effects of resistance training and chromium picolinate on body composition and skeletal muscle in older men.

The effects of chromium picolinate (CrPic) supplementation and resistance training (RT) on skeletal muscle size, strength, and power and whole body composition were examined in 18 men (age range 56-69 yr). The men were randomly assigned (double-blind) to groups (n = 9) that consumed either 17.8 micromol Cr/day (924 microg Cr/day) as CrPic or a low-Cr placebo for 12 wk while participating twice weekly in a high-intensity RT program. CrPic increased urinary Cr excretion approximately 50-fold (P < 0.001). RT-induced increases in muscle strength (P < 0.001) were not enhanced by CrPic. Arm-pull muscle power increased with RT at 20% (P = 0.016) but not at 40, 60, or 80% of the one repetition maximum, independent of CrPic. Knee-extension muscle power increased with RT at 20, 40, and 60% (P < 0.001) but not at 80% of one repetition maximum, and the placebo group gained more muscle power than did the CrPic group (RT by supplemental interaction, P < 0.05). Fat-free mass (P < 0.001), whole body muscle mass (P < 0.001), and vastus lateralis type II fiber area (P < 0.05) increased with RT in these body-weight-stable men, independent of CrPic. In conclusion, high-dose CrPic supplementation did not enhance muscle size, strength, or power development or lean body mass accretion in older men during a RT program, which had significant, independent effects on these measurements.

Speech-intelligibility improvements using a binaural adaptive-scheme based conceptually on human auditory processing.

A speech enhancement scheme is presented using diverse processing in sub-bands spaced according to a human-cochlear describing function. The binaural adaptive scheme decomposes the wide-band input signals into a number of band-limited signals, superficially similar to the treatment the human ears perform on incoming signals. The results of a series of intelligibility and formal listening tests are presented in which acoustic speech signals corrupted with recorded automobile noise were presented to 15 normal hearing volunteer subjects. For the experimental cases considered, the proposed binaural adaptive sub-band processing scheme delivers a statistically significant improvement in terms of both speech-intelligibility and perceived quality when compared with both the conventional wide-band processed and the noisy unprocessed case. The scheme is capable of extension to a potentially more flexible sub-band processing method based on a constrained artificial neural network (ANN).