Three years prospective clinical and radiologic follow-up of laparoscopic sacrocolpoperineopexy.

BACKGROUND: When Rectocele is part of a complex pelvic organ prolapse, a full repair is recommended. The aim of this study was to evaluate the clinical and radiological results after laparoscopic surgery in patients with symptomatic rectocele and III/IV stage vaginal vault prolapse METHODS: This is a prospective cohort study of women with symptomatic rectoceles and middle compartment prolapse operated on between 2013 and 2015, who underwent a laparoscopic sacrocolpoperineopexy with synthetic Y mesh attached to puborectalis muscles, the anterior and posterior vagina wall and the sacrum. The clinical outcomes measured were symptoms of prolapse, obstructive defecation syndrome and quality of life. Radiological outcomes were distance of the vaginal vault below pubococcigeal line and depth of rectovaginal wall protrusion in dynamic pelvic resonance. RESULTS: 33 patients were included. 32 of them remained asymptomatic after a three years follow-up. Significant differences were shown in the obstructed defecation score and quality of life after 6, 12 and 36 months compared to preoperatively. No differences were identified when the postoperative results were compared. Significant differences were shown in preoperative vaginal vault prolapse (3.2 cms ± 0.8 SD below the pubococcigeal Line) and rectocele size, compared with 1 and 3 years after surgery. There were no significant differences in vaginal vault prolapse when compared after 1 and 3 years. When rectocele size after 1 and 3 years was compared, significant differences were shown, but only one clinical recurrence (3%) was identified after a mean follow-up of 47 months. CONCLUSIONS: Laparoscopic sacrocolpoperineopexy in patients with symptomatic rectocele and III/IV vaginal vault prolapse solves the constipation and obstructed defecation with an excellent quality of life and low clinical recurrences. Radiological deterioration, especially in rectocele size, was identified in the mid-term follow-up without clinical significance.

Microbial communities of the olive mill wastewater sludge stored in evaporation ponds: The resource for sustainable bioremediation.

Olive Mill Wastewater (OMW) is a polluting residue from the olive oil industry. It is usually stored in open-air unprotected evaporation ponds where their sediments accumulate. This study compares the characteristics of OMW sludges stored for long-time in evaporation ponds and assesses their impact on the underlying soil layer. Physicochemical parameters, toxicity bioassays, and full characterization of the microbial community were analyzed. The extension of the polluting effects was assessed by analysis of toxicity, microbial biomass carbon, and respiration. Geostatistics was used to predict their spatial distribution. Organic matter and polyphenol content besides toxicity levels determine variations between OMW sludges and have a high impact on the microbiota they contain. The microbial community was abundant, diverse, and functionally active. However, the biodegradability of the sludges was hindered by the toxicity levels. Toxicity and biomass carbon were higher on the surface of the ponds than in the soil layer revealing a reduced leach flow and depletion of contaminants. The natural microbiota might be biostimulated by means of applying sustainable and feasible biological treatments in order to favor the OMW sludges bioremediation. These results open up the possibility of solving the environmental concern caused by its storage in similar scenarios, which are common in olive oil-producing countries.

Increased vulnerability to impulsive behavior after streptococcal antigen exposure and antibiotic treatment in rats.

RATIONALE: The inflammation induced by Group A Streptococcus (GAS) infection has been viewed as a vulnerability factor in mental disorders characterized by inhibitory control deficits, such as attention-deficit/hyperactivity disorder or obsessive-compulsive disorder. Antibiotic treatment reduces GAS symptoms; however, its effects on impulsivity have not been fully assessed. OBJECTIVES: We investigated whether GAS exposure during early adolescence might be a vulnerability factor for adult impulsivity, if antibiotic treatment acts as a protective factor, and whether these differences are accompanied by changes in the inflammatory cytokine frontostriatal regions. METHODS: Male Wistar rats were exposed to the GAS antigen or to vehicle plus adjuvants at postnatal day (PND) 35 (with two boosts), and they received either ampicillin (supplemented in the drinking water) or water alone from PND35 to PND70. Adult impulsivity was assessed using two different models, the 5-choice serial reaction time task (5-CSRT task) and the delay discounting task (DDT). The levels of interleukin-6 (IL-6) and IL-17 were measured in the prefrontal cortex (PFc), and the tumor necrosis factor α levels (TNFα) were measured in the PFc and nucleus accumbens (NAcc). RESULTS: GAS exposure and ampicillin treatment increased the waiting impulsivity by a higher number of premature responses when the animals were challenged by a long intertrial interval during the 5-CSRT task. The GAS exposure revealed higher impulsive choices at the highest delay (40 s) when tested by DDT, while coadministration with ampicillin prevented the impulsive choice. GAS exposure and ampicillin reduced the IL-6 and IL-17 levels in the PFc, and ampicillin treatment increased the TNFα levels in the NAcc. A regression analysis revealed a significant contribution of GAS exposure and TNFα levels to the observed effects. CONCLUSIONS: GAS exposure and ampicillin treatment induced an inhibitory control deficit in a different manner depending on the form of impulsivity measured here, with inflammatory long-term changes in the PFc and NAcc that might increase the vulnerability to impulsivity-related neuropsychiatric disorders.

Integral approach using bacterial microbiome to stabilize municipal solid waste.

Biological transformation of municipal solid waste is an environment-friendly management strategy against recalcitrant residues. The bacterial biome that inhabit said residues are responsible of decomposing both simple and complex materials. For this reason, processes such as composting, which favor the acceleration of the transformation of organic matter, can contribute to the degradation of municipal solid waste. Not only as mere fertilizer for crops, but also as methods for the recovery of solid waste. However, the control of the conditions necessary to achieve an optimal process on an industrial scale is a great concern. Thus, the aim of this work focuses on the characterization of the bacterial microbiome on three municipal solid waste facilities in order to deepen the role of microorganisms in the state of the final product obtained. For it, an intensive metagenomic analysis as well as a battery of physicochemical determinations were carried out. The lack of adequate thermophilic phases was decisive in finding certain bacterial genera, such as Lactobacillus, which was significant through these processes. Biodiversity did not follow a common pattern in the three processes, neither in abundance nor in richness but, in general, it was greater during the bio-oxidative stage. Despite the different trend in terms of the degradation of carbon fractions in these wastes, at the end of the biodegradation treatments, a sufficient degree of bioestabilization of the organic matter was reached. The results offer the opportunity to obtain a level of detail unprecedented of the structure, dynamics and function of the bacterial community in real conditions, without the control offered by laboratory conditions or pilot plants.

Dissecting the individual contribution of conserved cysteines to the redox regulation of RubisCO.

Oxidation of the cysteines from ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) leads to inactivation and promotes structural changes that increase the proteolytic sensitivity and membrane association propensity related to its catabolism. To uncover the individual role of the different cysteines, the sequential order of modification under increasing oxidative conditions was determined using chemical labeling and mass spectrometry. Besides, site-directed RubisCO mutants were obtained in Chlamydomonas reinhardtii replacing single conserved cysteines (Cys84, Cys172, Cys192, Cys247, Cys284, Cys427, Cys459 from the large and sCys41, sCys83 from the small subunit) and the redox properties of the mutant enzymes were determined. All mutants retained significant carboxylase activity and grew photoautotrophically, indicating that these conserved cysteines are not essential for catalysis. Cys84 played a noticeable structural role, its replacement producing a structurally altered enzyme. While Cys247, Cys284, and sCys83 were not affected by the redox environment, all other residues were oxidized using a disulfide/thiol ratio of around two, except for Cys172 whose oxidation was distinctly delayed. Remarkably, Cys192 and Cys427 were apparently protective, their absence leading to a premature oxidation of critical residues (Cys172 and Cys459). These cysteines integrate a regulatory network that modulates RubisCO activity and conformation in response to oxidative conditions.

Laparoscopic intracorporeal rectus aponeuroplasty (LIRA technique): a step forward in minimally invasive abdominal wall reconstruction for ventral hernia repair (LVHR).

BACKGROUND: Closing the defect (CD) during laparoscopic ventral hernia repair began to be performed in order to decrease seroma, to improve the functionality of the abdominal wall, and to decrease the bulging effect. However, tension at the incision after CD in large defects is related to an increased rate of pain and recurrence. We present the preliminary results of a new technique for medium midline hernias as an alternative to conventional CD. METHODS: A prospective controlled study was conducted from January 2015 to January 2017 to evaluate an elective new procedure (LIRA) performed on patients with midline ventral hernias (4-10 cm width). The posterior rectus aponeurosis was opened lengthwise around the hernia defect using a laparoscopic approach to create two flaps and was then sutured. The size of the flaps was estimated using a mathematical formula. An on-lay mesh was placed intraperitoneal overlapping the fascia defect. The data analyzed included patient demographics, operative parameters, and complications. A computerized tomography was performed preoperatively and postoperatively (1 month and 1 year) to evaluate recurrence, distance between rectus and seroma. RESULTS: Twelve patients were included. Mean width of the defect was 5.5 cm. Average VAS (24 h) was 3.9, 1.1 (1 month), and 0 (1 year). Mean preoperative distance between rectus was 5.5 cm; postoperative was 2.2 cm (1 year). Radiological seroma at first month was detected in 50%. Mean follow-up was 15 months. CONCLUSION: The LIRA technique could be considered as an alternative to conventional CD or endoscopic component separation for medium defects under 10 cm in width. This technique obtained a "no tension" effect that could be related to a lower rate of postoperative pain with no recurrence or bulging, being a safe, feasible, and reproducible technique.

Safety and effectiveness of self-adhesive mesh in laparoscopic ventral hernia repair using transabdominal preperitoneal route.

BACKGROUND: Laparoscopic ventral or incisional hernia repair requires intraperitoneal mesh placement. This is associated with an increase in adhesions, bowel obstruction and enterocutaneous fistula. Intraabdominal meshes are laparoscopically fixed using traumatic fixation methods that increase acute, chronic pain and adhesions to bowel loops. The aim was to check the safety and effectiveness of the laparoscopic approach in ventral or incisional hernia, using a self-adhesive mesh in the preperitoneal space without tacks or transfascial sutures, and to objectively assess its benefits and complications. METHODS: Patients aged between 18 and 67 years old with medial, lateral ventral and incisional hernias between 3 and 8 cm in size were included in this study. Fifty patients were included in the study, which was conducted between January 2013 and March 2015. RESULTS: The average length of surgery was 57.3 ± 18 min. The average hospital stay was 1.1 ± 0.3 days. The average time taken to return to work was 9.2 ± 2.4 days. The most common post-operative complication was seroma, which was observed in 13 patients (26 %). The average follow-up was 15.4 ± 5.5 months. Three patients were lost to follow-up during this period. There was no hernia recurrence during examination nor on CT scan during the follow-up period. The average score on the visual analogue scale before surgery was 4 ± 1. After surgery, the score was as follows: 3 ± 0.8 on the first day after surgery, 0.9 ± 0.5 after the first week, 0.4 ± 0.4 after the first month and 0 after 90 days. No patient showed chronic pain. Overall satisfaction (VAS for surgery) was 8.3 ± 0.6. CONCLUSIONS: The use of self-adhesive meshes during the laparoscopic transabdominal preperitoneal approach in small- and medium-sized ventral or incisional hernias is safe and effective, with low post-operative pain, quick functional recovery and high overall satisfaction after surgery with no increase in recurrence in the short term.

Correction to: Safety and effectiveness of self-adhesive mesh in laparoscopic ventral hernia repair using transabdominal preperitoneal route.

The metadata listed the wrong given names and family names.

Control of the ribulose 1,5-bisphosphate carboxylase/oxygenase activity by the chloroplastic glutathione pool.

The CO2-fixing activity of ribulose 1,5-bisphosphate carboxylase/oxygenase depends on the redox state of its cysteines. Disulfides like cystamine or 5,5'-dithio-bis(2-nitrobenzoic acid), but not oxidized glutathione, switch the enzyme to the inactive oxidized form. Conversely, thiols like cysteamine, cysteine, dithiotreitol or 2-mercaptoethanol, but not reduced glutathione, recover enzymatic activity after a previous oxidation. Direct regulation of the carboxylase activity by the chloroplastic glutathione pool is hindered by kinetic barriers impeding access to the critical residues. However, reduced glutathione can drive the recovery of activity by means of minute amounts of smaller intermediary thiol/disulfide exchangers. In contrast, oxidized glutathione does not inactivate the enzyme even in the presence of these intermediaries. This asymmetrical effect should help to maintain the enzyme in the active form in vivo.

What do you mean by transcription rate?: the conceptual difference between nascent transcription rate and mRNA synthesis rate is essential for the proper understanding of transcriptomic analyses.

mRNA synthesis in all organisms is performed by RNA polymerases, which work as nanomachines on DNA templates. The rate at which their product is made is an important parameter in gene expression. Transcription rate encompasses two related, yet different, concepts: the nascent transcription rate, which measures the in situ mRNA production by RNA polymerase, and the rate of synthesis of mature mRNA, which measures the contribution of transcription to the mRNA concentration. Both parameters are useful for molecular biologists, but they are not interchangeable and they are expressed in different units. It is important to distinguish when and where each one should be used. We propose that for functional genomics the use of nascent transcription rates should be restricted to the evaluation of the transcriptional process itself, whereas mature mRNA synthesis rates should be employed to address the transcriptional input to mRNA concentration balance leading to variation of gene expression.

mRNAStab--a web application for mRNA stability analysis.

Eukaryotic gene expression is regulated both at the transcription and the mRNA degradation levels. The implementation of functional genomics methods that allow the simultaneous measurement of transcription (TR) and degradation (DR) rates for thousands of mRNAs is a huge improvement in this field. One of the best established methods for mRNA stability determination is genomic run-on (GRO). It allows the measurement of DR, TR and mRNA levels during cell dynamic responses. Here, we offer a software package that provides improved algorithms for determination of mRNA stability during dynamic GRO experiments.

Enzymatic characterization of microbial isolates from lignocellulose waste composting: chronological evolution.

Successful composting is dependent upon microbial performance. An interdependent relationship is established between environmental and nutritional properties that rule the process and characteristics of the dominant microbial communities. To reach a better understanding of this relationship, the dynamics of major metabolic activities associated with cultivable isolates according to composting phases were evaluated. Ammonification (72.04%), amylolysis (35.65%), hemicellulolyis (30.75%), and proteolysis (33.61%) were the more frequent activities among isolates, with mesophilic bacteria and fungi as the prevalent microbial communities. Bacteria were mainly responsible for starch hydrolysis, while a higher percentage of hemicellulolytic and proteolytic isolates were ascribable to fungi. Composting seems to exert a functional selective effect on microbial communities by promoting the presence of specific metabolically dominant groups at each stage of the process. Moreover, the application of conglomerate analysis led to the statement of a clear correlation between the chronology of the process and characteristics of the associated microbiota. According to metabolic capabilities of the isolates and their density, three clear clusters were obtained corresponding to the start of the process, including the first thermophilic peak, the rest of the bio-oxidative stage, and the maturation phase.

Clinical and Biochemical Characteristics of Hemophagocytic Lymphohistiocytosis in People Living With HIV and Disseminated Histoplasmosis at a Tertiary Hospital in Mexico.

Background: Hemophagocytic lymphohistiocytosis (HLH) is considered a rare disease with high morbidity and mortality risks. Most research on this disease is conducted in pediatric settings. Therefore, this study aimed to describe the clinical characteristics, laboratory findings, and outcomes related to HLH in people living with human immunodeficiency virus (HIV)/AIDS) and disseminated histoplasmosis. Methods: A retrospective and descriptive study was conducted in a tertiary hospital in México City from January 2018 to December 2022, including people living with HIV who had disseminated histoplasmosis confirmed through direct microbiological or immunological methods with an HScore ≥169 or who met 5 of the 8 HLH-2004 criteria. Results: HLH occurred in 36.1% (n = 26) of patients with HIV and disseminated histoplasmosis; the majority were men (84.9%), and their mean age (standard deviation) was 30.19 (5.6) years. The most frequent clinical manifestations were hepatomegaly (100%), fever (96.2%), and dyspnea (84.6%). The most common biochemical changes were hyperferritinemia (100%), elevated lactate dehydrogenase (100%), and bicytopenia (61.5%). Partial thromboplastin time (P = .012) and prothrombin time (P = .004) were associated with the 30-day mortality rate, and the 30-day survival rate was 65.4%. Conclusions: We detected a high frequency of HLH; therefore, we encourage physicians to use diagnostic prediction tools (HLH-2004 and HScore criteria) in each reassessment for timely detection.

Reversible inhibition of CO2 fixation by ribulose 1,5-bisphosphate carboxylase/oxygenase through the synergic effect of arsenite and a monothiol.

The activity of the photosynthetic carbon-fixing enzyme, ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), is partially inhibited by arsenite in the millimolar concentration range. However, micromolar arsenite can fully inhibit Rubisco in the presence of a potentiating monothiol such as cysteine, cysteamine, 2-mercaptoethanol or N-acetylcysteine, but not glutathione. Arsenite reacts specifically with the vicinal Cys172-Cys192 from the large subunit of Rubisco and with the monothiol to establish a ternary complex, which is suggested to be a trithioarsenical. The stability of the complex is strongly dependent on the nature of the monothiol. Enzyme activity is fully recovered through the disassembly of the complex after eliminating arsenite and/or the thiol from the medium. The synergic combination of arsenite and a monothiol acts also in vivo stopping carbon dioxide fixation in illuminated cultures of Chlamydomonas reinhardtii. Again, this effect may be reverted by washing the cells. However, in vivo inhibition does not result from the blocking of Rubisco since mutant strains carrying Rubiscos with Cys172 and/or Cys192 substitutions (which are insensitive to arsenite in vitro) are also arrested. This suggests the existence of a specific sensor controlling carbon fixation that is even more sensitive than Rubisco to the arsenite-thiol synergism.

Sevoflurane, but not propofol, reduces the lung inflammatory response and improves oxygenation in an acute respiratory distress syndrome model: a randomised laboratory study.

CONTEXT: Acute respiratory distress syndrome is characterised by activation of the inflammatory cascade. The only treatment that reduces the mortality rate associated with this syndrome is lung protective ventilation, which requires sedation of patients. Sedation in critical care units is usually induced intravenously, although there is reason to believe that inhaled anaesthetics are a suitable alternative. Sevoflurane has recently been shown to modulate the lung inflammatory response in a model of lung injury more favourably than propofol. OBJECTIVE: The goal of this study was to confirm whether or not sevoflurane is more effective than propofol in ameliorating the inflammatory response in an animal model of acute respiratory distress syndrome. DESIGN: A prospective, randomised, controlled study. SETTING: Research foundation laboratory at the Hospital Clínico Universitario, Valencia, Spain. EXPERIMENTAL ANIMALS: Sixteen Landrace/large white crossbred pigs weighing 30 to 45 kg. INTERVENTIONS: Animals were allocated randomly to one of two groups: one sedated with intravenous propofol 5 to 7 mg kg h (group P) and the other with sevoflurane, administered using an AnaConDa device to obtain an end-tidal concentration of 1.5% (group S). Monitoring, lung protective ventilation and anaesthetic management were identical in both groups. MAIN OUTCOME MEASURES: The PaO2/FiO2 ratio and cytokine concentrations in bronchoalveolar lavage specimens were determined at 10, 150 and 240 min after confirmation of acute respiratory distress syndrome (PaO2/FiO2 <26.7 kPa). RESULTS: At 240 min, median and interquartile range (IQR) concentrations of cytokines in bronchial lavage specimens in group S were lower than those in group P [interleukin-1ß (IL-1ß) 53, IQR 16-140 vs. 311, IQR 183-637 pg ml, P = 0.04; tumour necrosis factor-α 347, IQR 161-433 vs. 552, IQR 475-649 pg ml, P = 0.04; and IL-6 101, IQR 76-282 vs. 580, IQR 369-701 pg ml, P = 0.03]. The polymorphonuclear neutrophil count was also lower in group S (P = 0.007), which also had a higher PaO2/FiO2 ratio. TRIAL REGISTRATION: GE-015/09. CONCLUSION: In an animal model of acute respiratory distress syndrome, sevoflurane ameliorates the lung inflammatory response and improves oxygenation to a greater extent than propofol.

Magnetic-assisted single-port sleeve gastrectomy.

BACKGROUND: Sleeve gastrectomy is a recent, purely restrictive procedure in bariatric surgery that has shown results similar to gastric bypass over the short and middle term. At the same time, single-port access surgery has fostered the development of new techniques and methods seeking better cosmetic results and less postoperative pain, while maintaining the satisfactory results obtained by the standard laparoscopic approach. One of the problems associated to single-access surgery is the lack of traction and the difficulties to retract the liver. The authors' aim was to try to avoid additional trocars or sutures in order to perform pure single-incision surgery, using 2 magnetic forceps. METHODS: The authors present the case of a 51-year-old morbidly obese female (body mass index = 44.82) who underwent a pure single-access laparoscopic sleeve gastrectomy with no additional trocars or sutures and assisted by 2 neodymium magnetic forceps: one to retract the liver and the other to retract the stomach in order to provide sufficient triangulation for adequate exposure of the surgical field during dissection. RESULTS: The procedure was completed in 120 minutes. No preoperative or postoperative complications were recorded, and the patient was discharged 2 days after surgery. CONCLUSION: Single-port access sleeve gastrectomy assisted by magnetic forceps is feasible and safe in the hands of experienced laparoscopic surgeons, solving one of the problems associated to this type of surgery, that is, the need for an additional trocar and needles or sutures to retract the liver and stomach in order to perform the operation.

Fourteen years of continuous soil moisture records from plant and biocrust-dominated microsites.

Drylands cover ~41% of the terrestrial surface. In these water-limited ecosystems, soil moisture contributes to multiple hydrological processes and is a crucial determinant of the activity and performance of above- and belowground organisms and of the ecosystem processes that rely on them. Thus, an accurate characterisation of the temporal dynamics of soil moisture is critical to improve our understanding of how dryland ecosystems function and are responding to ongoing climate change. Furthermore, it may help improve climatic forecasts and drought monitoring. Here we present the MOISCRUST dataset, a long-term (2006-2020) soil moisture dataset at a sub-daily resolution from five different microsites (vascular plants and biocrusts) in a Mediterranean semiarid dryland located in Central Spain. MOISCRUST is a unique dataset for improving our understanding on how both vascular plants and biocrusts determine soil water dynamics in drylands, and thus to better assess their hydrological impacts and responses to ongoing climate change.

Specific and global regulation of mRNA stability during osmotic stress in Saccharomyces cerevisiae.

Hyperosmotic stress yields reprogramming of gene expression in Saccharomyces cerevisiae cells. Most of this response is orchestrated by Hog1, a stress-activated, mitogen-activated protein kinase (MAPK) homologous to human p38. We investigated, on a genomic scale, the contribution of changes in transcription rates and mRNA stabilities to the modulation of mRNA amounts during the response to osmotic stress in wild-type and hog1 mutant cells. Mild osmotic shock induces a broad mRNA destabilization; however, osmo-mRNAs are up-regulated by increasing both transcription rates and mRNA half-lives. In contrast, mild or severe osmotic stress in hog1 mutants, or severe osmotic stress in wild-type cells, yields global mRNA stabilization and sequestration of mRNAs into P-bodies. After adaptation, the absence of Hog1 affects the kinetics of P-bodies disassembly and the return of mRNAs to translation. Our results indicate that regulation of mRNA turnover contributes to coordinate gene expression upon osmotic stress, and that there are both specific and global controls of mRNA stability depending on the strength of the osmotic stress.

Oral involvement in mucormycosis. A retrospective study of 55 cases.

INTRODUCTION: Mucormycosis with oral involvement (OIM) is a rare opportunistic and lethal mycosis, which has increased in the last decade and is generally associated with uncontrolled diabetes and neutropenia. METHODS: A retrospective study of cases with OIM was carried out in a tertiary-care center. Mycological and histological examinations were performed, and the isolated organisms were identified by morphology and molecular biology. RESULTS: Fifty-five OIM patients were included, with a median age of 38 years (61.8% males). The most frequent associated disease was type-2 diabetes mellitus (61%), followed by neutropenia due to acute lymphocytic leukemia (27%). The main presentation was palatal and mandibular ulcers (92.7%) and, to a lesser extent, gingival and lingual necrosis. The diagnosis was established by mycological and histopathological studies. The most frequent fungi isolated was Rhizopus arrhizus (67.2%). CONCLUSION: OIM is a rapidly progressing disease, therefore, an early diagnosis and the proper control of predisposing factors is necessary, and consequently, contributing to improve the outcome of mucormycosis.

Genomics and gene transcription kinetics in yeast.

As an adaptive response to new conditions, mRNA concentrations in eukaryotes are readjusted after any environmental change. Although mRNA concentrations can be modified by altering synthesis and/or degradation rates, the rapidity of the transition to a new concentration depends on the regulation of mRNA stability. There are several plausible transcriptional strategies following environmental change, reflecting different degrees of compromise between speed of response and cost of synthesis. The recent development of genomic techniques now enables researchers to determine simultaneously (either directly or indirectly) the transcription rates and mRNA half-lifes, together with mRNA concentrations, corresponding to all yeast genes. Such experiments could provide a new picture of the transcriptional response, by enabling us to characterize the kinetic strategies that are used by different genes under given environmental conditions.