Time-dependent molecular emission in IRC+10216.

CONTEXT: The variability in IRC+10216, the envelope of the asymptotic giant branch (AGB) star CW Leo, has attracted increasing attention in recent years. Studying the details of this variability in the molecular emission required a systematic observation program. AIMS: We aim to reveal and characterize the periodical variability of the rotational lines from several molecules and radicals in IRC+10216, and to compare it with previously reported IR variability. METHODS: We carried out systematic monitoring within the ~80 to 116 GHz frequency range with the IRAM 30m telescope. RESULTS: We report on the periodical variability in IRC+10216 of several rotational lines from the following molecules and radicals: HC3N, HC5N, CCH, C4H, C5H, and CN. The analysis of the variable molecular lines provides periods that are consistent with previously reported IR variability, and interesting phase lags are revealed that point toward radiative transfer and pumping, rather than chemical effects. CONCLUSIONS: This study indicates that observations of several lines of a given molecule have to be performed simultaneously or at least at the same phase in order to avoid erroneous interpretation of the data. In particular, merging ALMA data from different epochs may prove to be difficult, as shown by the example of the variability we studied here. Moreover, radiative transfer codes have to incorporate the effect of population variability in the rotational levels in CW Leo.

Herschel/HIFI observations of the circumstellar ammonia lines in IRC+10216.

CONTEXT: A discrepancy exists between the abundance of ammonia (NH3) derived previously for the circumstellar envelope (CSE) of IRC+10216 from far-IR submillimeter rotational lines and that inferred from radio inversion or mid-infrared (MIR) absorption transitions. AIMS: To address the discrepancy described above, new high-resolution far-infrared (FIR) observations of both ortho- and para-NH3 transitions toward IRC+10216 were obtained with Herschel, with the goal of determining the ammonia abundance and constraining the distribution of NH3 in the envelope of IRC+10216. METHODS: We used the Heterodyne Instrument for the Far Infrared (HIFI) on board Herschel to observe all rotational transitions up to the J = 3 level (three ortho- and six para-NH3 lines). We conducted non-LTE multilevel radiative transfer modelling, including the effects of near-infrared (NIR) radiative pumping through vibrational transitions. The computed emission line profiles are compared with the new HIFI data, the radio inversion transitions, and the MIR absorption lines in the ν2 band taken from the literature. RESULTS: We found that NIR pumping is of key importance for understanding the excitation of rotational levels of NH3. The derived NH3 abundances relative to molecular hydrogen were (2.8 ± 0.5) × 10-8 for ortho-NH3 and [Formula: see text] for para-NH3, consistent with an ortho/para ratio of 1. These values are in a rough agreement with abundances derived from the inversion transitions, as well as with the total abundance of NH3 inferred from the MIR absorption lines. To explain the observed rotational transitions, ammonia must be formed near to the central star at a radius close to the end of the wind acceleration region, but no larger than about 20 stellar radii (1σ confidence level).

Discovery of Time Variation of the Intensity of Molecular Lines in IRC+10216 in The Submillimeter and Far Infrared Domains.

We report on the discovery of strong intensity variations in the high rotational lines of abundant molecular species towards the archetypical circumstellar envelope of IRC+10216. The observations have been carried out with the HIFI instrument on board Herschel and with the IRAM 30-m telescope. They cover several observing periods spreading over 3 years. The line intensity variations for molecules produced in the external layers of the envelope most probably result from time variations in the infrared pumping rates. We analyze the main implications this discovery has on the interpretation of molecular line emission in the envelopes of Mira-type stars. Radiative transfer calculations have to take into account both the time variability of infrared pumping and the possible variation of the dust and gas temperatures with stellar phase in order to reproduce the observation of molecular lines at different epochs. The effect of gas temperature variations with stellar phase could be particularly important for lines produced in the innermost regions of the envelope. Each layer of the circumstellar envelope sees the stellar light radiation with a different lag time (phase). Our results show that this effect must be included in the models. The sub-mm and FIR lines of AGB stars cannot anymore be considered as safe intensity calibrators.

Hydride spectroscopy of the diffuse interstellar medium: new clues on the gas fraction in molecular form and cosmic ray ionization rate in relation to H3+.

The Herschel-guaranteed time key programme PRobing InterStellar Molecules with Absorption line Studies (PRISMAS)(1) is providing a survey of the interstellar hydrides containing the elements C, O, N, F and Cl. As the building blocks of interstellar molecules, hydrides provide key information on their formation pathways. They can also be used as tracers of important physical and chemical properties of the interstellar gas that are difficult to measure otherwise. This paper presents an analysis of two sight-lines investigated by the PRISMAS project, towards the star-forming regions W49N and W51. By combining the information extracted from the detected spectral lines, we present an analysis of the physical properties of the diffuse interstellar gas, including the electron abundance, the fraction of gas in molecular form, and constraints on the cosmic ray ionization rate and the gas density.

Young-age onset of colorectal cancer in Israel.

AIM: The study was conducted to investigate the differences in clinical-pathological, ethnic, and demographic presentations and the expression of mismatch repair proteins in a cohort of young-onset (50 years) with colorectal cancer. MATERIALS AND METHODS: Clinical, demographic, and histopathological data of patients with colorectal cancer were collected retrospectively from medical records and pathology reports. RESULTS: Ninety patients, 50 years of age or younger with a mean age of 42 years were compared with a group of 190 patients above 50 years of 50 (see Table 1). Sixty percent of the young-onset patients were females, compared to 40% in the older age group (P = 0.02). Twenty-one percent of the young-onset patients were Arabs as compared to 2% of older-onset patients (P = 0.001). Younger patients displayed a higher percentage of mucinous cancers and a higher percentage of diagnosis at an advanced stage of disease; 40% of young-onset versus 31% of older-onset patients presented Duke's stages C and D (P = 0.02). CONCLUSIONS: Younger age of onset colorectal cancer in our cohort of Israeli patients is associated with higher percentage of Arab patients, mucinous cancers, female gender, and advanced stage at diagnosis.

Emergency surgery for complicated acute diverticulitis.

AIM: Antecedent attacks of diverticulitis are thought to increase the risk of complicated diverticulitis, and unless elective surgery is performed, a high proportion of patients with recurrent symptoms will require emergency operations for complicated diverticulitis with its associated morbidity. In this multicentre study, we aim to assess impact of previous attacks of diverticulitis on patients requiring an emergency surgical intervention. METHOD: All patients operated on as an emergency for complicated diverticulitis were retrospectively analysed. Patients were separated into two groups: group A included patients without previous history of diverticular disease, and group B those with previous attacks of diverticulitis. RESULTS: A total of 96 patients were included in the study. Group A included 68 (70.8%) patients, and group B 28 (29.2%) patients. Generalized peritonitis was the reason for operation in 50 (73.5%) patients in-group A and only four (14%) patients in group B. Perforated diverticulitis occurred more often in group A, whereas pericolonic abscess and phlegmon formation occurred more commonly in group B. Resection was performed in all patients in group B; 50% had a Hartmann's procedure, and the other 50% patients had primary anastomosis. Hartmann's procedure was performed in 52 patients (76.5%) in group A, and 8 patients (11.7%) had resection and primary anastomosis. No difference in postoperative complications was identified between the groups. CONCLUSION: Multiple attacks of diverticulitis are not associated with an increased risk of complicated diverticulitis. Recurrent episodes of diverticulitis are not associated with a less favourable outcome or an increased risk of fatality if complications ensue.

Ligation under vision of haemorrhoidal cushions for therapy of bleeding haemorrhoids.

Ligation under vision (LUV) is a simple method for the surgical treatment of haemorrhoids. In this study, we evaluated the results of our initial experience with the procedure in terms of postoperative pain, patients' final satisfaction and complications. We reviewed a group of patients who had undergone suture ligation of symptomatic haemorrhoids of grade II and III. This was performed with the haemorrhoids under direct vision and without the use of any ancillary instrumentation such as a Doppler sensor. All interventions were performed in the day-care surgical unit using general or regional anaesthesia. Surgical outcome and degree of postoperative pain were determined from outpatient clinic follow-up and individual phone interviews. A total of 32 patients (19 men and 13 women) with a mean age of 59 years had undergone LUV. There were 23 patients (72%) with grade II and 9 patients (28%) with grade III haemorrhoids. The indication for the surgery was bleeding in 19 patients (59%), prolapse in 6 (19%) and both in 7 (22%). A previous rubber band ligation had been carried out in 17 patients (53%). On average, the surgery took 22 min. All patients were discharged on the same day. Four %patients (12%) suffered only mild postoperative pain, 14 (44%) suffered from moderate pain and another 14 (44%) had severe pain. At follow-up (median 21 months, range 9-33 months), 28 %patients (87.5%) were completely asymptomatic at the time of the phone interview. The final result was assessed as excellent by 19 patients (60%), successful by 10 (31%), and unsuccessful by 3 (9%). All patients had complete functional recovery and there were no major surgical complications. Our data show that LUV of symptomatic haemorrhoids is a simple and safe procedure. It can be performed as effective isolated surgery for symptomatic haemorrhoids and as an additional procedure in the treatment of complex perianal pathology.

Compact retarding-potential Mott polarimeter.

A simple compact retarding-potential Mott polarimeter is described that operates at an electron accelerating voltage of 25 kV. With a thorium target the instrument provides efficiencies eta [=S2eff(I/I0), where Seff is the effective asymmetry (Sherman) function and I/I0 is the scattering efficiency] of approximately 1.3 x 10(-4) which are similar to the best values obtained using earlier Mott polarimeters. The present instrument, however, occupies a much smaller volume and is suitable for a wide range of applications involving angle- and/or energy-resolved polarization measurements.

Suppressive effect of aspirin on aberrant crypt foci in patients with colorectal cancer.

BACKGROUND: and aims: Aspirin and other non-steroidal anti-inflammatory drugs have been shown to reduce the risk of colorectal cancer (CRC). Animal models have shown that aspirin is also effective in reducing the density of aberrant crypt foci (ACF). The aim of the study was to evaluate the effect of chronic administration of aspirin on the distribution pattern and histological characteristics of ACF in patients with CRC. METHODS: Our study compared the distribution patterns and histomorphological characteristics of ACF between a group of CRC patients treated with low dose aspirin (n=59) and a control group without aspirin (n=135). ACF were visualised on methylene blue stained macroscopically normal mucosa, microdissected, and serially cut. RESULTS: ACF were found in 75.8% of mucosal samples from the control group and in 36% of mucosal samples from the aspirin treated group, indicating a 47% decline in prevalence of ACF in colonic samples of patients treated with aspirin. A significant reduction from 92.5% to 40% (p<0.0001) was found in distal large bowel samples containing one or more ACF. Similarly, the aspirin treated group showed a reduction in ACF density of 64% and 82%, respectively, in both proximal and distal parts of the colon, indicating a significant reduction in ACF/cm(2) in distal colon samples (p<0.01). The aspirin treated group displayed a 52% reduction in dysplastic ACF although this difference was not statistically significant. CONCLUSIONS: Our study has provided evidence of the effective chemopreventive action of low dose aspirin on ACF in humans.

Interaction of the metal chelator 2,3-dimercapto-1-propanesulfonate with the rabbit multispecific organic anion transporter 1 (rbOAT1).

The metal chelator DMPS (2,3-dimercapto-1-propanesulfonate) is used to treat heavy metal intoxication because it increases renal excretion of these toxins, which are accumulated in proximal tubule cells. To evaluate the involvement of the organic anion transporter 1 (OAT1) in the renal flux of DMPS, we examined the effect of DMPS on transport mediated by the rabbit ortholog of OAT1 and compared these characteristics with those observed in intact isolated rabbit proximal tubules. The rabbit OAT1 (rbOAT1) cDNA consisted of 2124 base pairs encoding a protein of 551 amino acids. Heterologous expression in COS-7 cells revealed rbOAT1-mediated transport of p-aminohippurate (PAH; K(t) = 16 microM). A 1 mM concentration of unlabeled PAH, alpha-ketoglutarate, urate, or probenecid inhibited [(3)H]PAH uptake by 70 to 90%. cis-Inhibition and trans-stimulation experiments using several Krebs cycle intermediates implicated alpha-ketoglutarate as the main intracellular exchange anion. Reduced DMPS inhibited rbOAT1-mediated fluorescein transport with an apparent K(i) of 102 microM. These characteristics paralleled those observed in isolated rabbit proximal tubules. PAH was transported into nonperfused single proximal tubule S(2) segments with a K(t) of 76 microM. DMPS inhibited FL uptake into single tubule segments with a K(i-app) of 71 microM. Fluorescein efflux from preloaded tubules was trans-stimulated by 1 mM PAH and 1 mM DMPS, consistent with DMPS entry into tubule cells by rbOAT1. In summary, rbOAT1 mediates basolateral uptake of DMPS into proximal tubule cells, implicating this process in the detoxification process of heavy metals in the kidneys.

Discovery of water vapour around IRC+10216 as evidence for comets orbiting another star.

Since 1995, planets with masses comparable to that of Jupiter have been discovered around approximately 60 stars. These planets have not been seen directly, but their presence has been inferred from the small reflex motions that they gravitationally induce on the star they orbit; these motions result in small periodic wavelength shifts in the stellar spectrum. The presence of analogues of the smaller bodies in our Solar System cannot, however, be determined using this technique, because the induced reflex motions are too small-so an alternative approach is needed. Here we report the observation of circumstellar water vapour around the ageing carbon star IRC+10216; water is not expected in measurable quantities around such a star. The only plausible explanation for this water is that the recent evolution of IRC+10216, which has been accompanied by a prodigious increase in its luminosity, is causing the vaporization of a collection of orbiting icy bodies-a process considered in an earlier theoretical study.

Fluorescent bone viewed through toenails of living animals: a method to observe bone regrowth.

We have developed a new method to observe bone and to document growth in living animals. The technique involves injecting calcein, a fluorescent calcium deposition marker, waiting approximately 4 hr for it to clear the vascular system, and observing bone directly through the toenails of lightly anesthetized living animals. Bone regrowth can be monitored in situ by amputating the digit through the nail plate, waiting the desired number of days, and injecting a second fluorescent label, alizarin red. Bone that has regrown since the amputation appears as a red area distal to the green calcein label on toes of lightly anesthetized animals when viewed under FITC fluorescence. This method has been used to demonstrate blocked bone synthesis and to quantitate significant differences in bone growth in control and experimental toes of individual animals. Advantages of this method include its simplicity, the use of fewer animals to collect sequential data, and increased reliability of repeated microscopic measurements using the same animal.

Denervation retards but does not prevent toetip regeneration.

Toetips of mammals regrow after amputation by a process similar, but not identical, to that which occurs during regeneration of a newt limb. Nerve is needed as a mitotic stimulant for newt limb regeneration but the requirement for nerve during rodent digit-tip regeneration is not known. Nerve dependence in rats was tested by severing the sciatic nerve in one hindlimb, amputating digit-tips from the central digits of both hind feet, and comparing the amount of regrowth in innervated and denervated digits. Denervation delayed soft-tissue wound healing. However, denervation did not significantly affect bone regrowth when animals were examined at one month. Because we suspected delayed bone regrowth, we used a new method that we developed to follow bone growth at several time points in each animal. Termed visible bone fluorescence through nail, this technique used serial injections of fluorescent calcium-deposition markers and observation through the toenails to observe bone growth in living animals. Using this method it was possible to detect retarded bone regrowth in denervated digits. Thus, although denervation of rodent tips delayed both soft tissue healing and bone regrowth, it did not prevent ultimate restitution of the amputated part. This suggests that neurotrophic stimulation in the mammalian digit-tip is not identical to that documented during newt limb regeneration, and that growth stimulation may be provided by tissues other than nerve.

Specificity of TUNEL method depends on duration of fixation.

Recent evidence has suggested that apoptosis plays an important role in various diseases, but concerns about the specificity of the TUNEL method for detecting apoptosis have been raised. The purpose of the present study was to investigate the specificity of the TUNEL method by using immersion and perfusion fixed tissues from both normal rats and rats with heart failure. Although a few positive cells were observed in perfusion fixed tissues, a significant number of positive cells were observed in immersion fixed tissues, especially when fixed tissues were kept for an extended time before the TUNEL assay was applied. The results of TUNEL staining should be interpreted with caution. When immersion fixation is used, fixed tissues should be assayed by the TUNEL method before the DNA degenerates.

Is apoptosis present in progression to chronic hypertensive heart failure?

BACKGROUND: Cardiomyocyte apoptosis is believed to occur in hypertension. Isolated myocyte data from spontaneously hypertensive heart failure (SHHF) rats, however, suggest that significant myocyte loss does not occur in this model. To investigate this issue further, heart sections from failing and nonfailing SHHF rats were examined by using in situ terminal deoxynucleotidyltransferase-mediated 2'-deoxyuridine 5'-triphosphate nick end-labeling (TUNEL). Additional hearts were optimally fixed by perfusion with glutaraldehyde and histologically examined for evidence of myocyte damage or loss. METHODS AND RESULTS: Five Sprague-Dawley (SD) rats, 8 failing SHHF rats, and 6 nonfailing SHHF rats were perfusion-fixed with formaldehyde and used for TUNEL assay. Heart sections from each group were also treated with DNase for positive controls. There were no significant differences in the number of TUNEL-positive cells in SD, failing SHHF, and nonfailing SHHF rats. Additionally, extensive screening of 1-microm sections of optimally fixed failing hearts revealed little evidence of myocyte loss or nuclear characteristics suggestive of apoptosis. CONCLUSION: Apoptosis does not appear to be an important component of myocardial remodeling in SHHF rats during hypertrophy or end-stage heart failure. Examination of myocyte nuclear structure by high-resolution microscopy of optimally fixed tissues is recommended as an alternative approach to study apoptosis.

Treatment of acute colonic pseudo-obstruction with neostigmine.

BACKGROUND: Colonic pseudo-obstruction is a poorly understood syndrome, described by Ogilvie, and characterized by signs of large-bowel obstruction, without a mechanical cause. An imbalance in the autonomic nerve supply to the colon has been suggested as the pathophysiology. Recently, promising results with pharmacologic manipulation with neostigmine have been described. STUDY DESIGN: A prospective study was undertaken with 11 consecutive patients with clinical and radiologic signs of colonic pseudo-obstruction, in one general hospital, over a 1-year period. Patients were treated primarily with 2.5 mg of neostigmine in 100 mL of saline for 1 hour, under cardiac monitoring. Results were assessed by the clinical and radiologic responses. RESULTS: Rapid and effective spontaneous decompression of the colon was achieved in 8 patients after a single dose of neostigmine, within a mean of 90 minutes from the beginning of treatment. In another two patients decompression occurred only after a second dose was administered 3 hours after the first dose. In one patient, no changes were observed and colonoscopic decompression was performed. No significant bradycardia was observed in any of the patients. CONCLUSIONS: Neostigmine is a simple, safe, and effective therapy for treatment of colonic pseudo-obstruction.

[Laparoscopic cholecystectomy--1,000 procedures in a surgical department].

The first 1,000 laparoscopic cholecystectomies performed in our department were reviewed. There was no operative mortality; conversion to open cholecystectomy was necessary in 2%. In the last 600 cases the rate of conversion had decreased to 0.5%. There was common bile duct injury in 0.3%, with the injuries identified during primary surgery. This clinical experience is consistent with previous studies, which proved that laparoscopic cholecystectomy is safe and should replace open operation as the procedure of choice.

Octreotide treatment in patients with severe acute pancreatitis.

We investigated the effect of octreotide in the treatment of severe acute pancreatitis in a case-control study. Experimental and clinical studies on the effect of octreotide in the treatment of acute pancreatitis have shown controversial results. Since January 1992, we have been conducting a prospective randomized study on the effect of octreotide in severe acute pancreatitis, in three hospitals in Israel. The entering criteria included three or more of the Ranson prognostic signs and CT findings of severe pancreatitis. Patients were randomly assigned to conservative treatment either with or without octreotide (0.1 mg subcutaneously three times a day). The end points of the study included: complication rate (ARDS, sepsis, renal failure, pseudocyst, fistula, and abscess), length of hospital stay, and mortality. From January 1992 to December 1996, 60 patients entered the study. After evaluating the files, 10 patients were excluded due to failure to meet the entering criteria, incomplete data, or incorrect diagnosis. Of the remaining 50 patients, 25 were assigned to octreotide (treatment group) and 25 to conservative treatment only (control group). The two groups matched with regard to age, sex, etiology, and severity of the disease. The complication rate was lower in the treatment group with regard to sepsis (24% vs 76%, P = 0.0002) and ARDS (28% vs 56%, P = 0.04). The hospital stay was shorter in the treatment group (20.6 vs 33.1 days, P = 0.04). Two patients died in the treatment group and eight in the control group (P < 0.019). These results suggest that octreotide may have a beneficial effect in the treatment of severe acute pancreatitis.

Bone growth is induced by nail transplantation in amputated proximal phalanges.

Mammals are able to regrow the tips of amputated fingers and toes. However, regrowth is limited to regions covered by, and is dependent upon, the presence of the nail organ. If the nail organ is responsible for bone growth in digit-tips, we reasoned that transplanted nail organ might also be able to induce outgrowth from other levels of the digit. Partial nail organ has been transplanted to amputated proximal phalanges of young rats. To date, six transplants have successfully produced outgrowth of nail. New bone growth, not seen in control amputated digits, was documented by x-ray and by alizarin red and calcein injections to be directed toward implanted nail organ. These results support an inductive role for nail organ epithelium in bone growth after amputation and provide encouragement for attempts to enhance a positive outcome after appendage amputation.