Physicians' Knowledge of Cardiopulmonary Resuscitation Guidelines and Current Certification Status at the University Hospital of the West Indies, Jamaica.

OBJECTIVE: To determine physicians' knowledge of cardiopulmonary resuscitation (CPR) guidelines at the University Hospital of the West Indies (UHWI), Jamaica, and their current certification status in basic life support (BLS), advanced cardiac life support (ACLS), paediatric advanced life support (PALS) and advanced trauma life support (ATLS). METHODS: This was a cross-sectional study. A 23-item self-administered questionnaire was used to assess physicians practising at the UHWI, from the Departments of Anaesthesia, Surgery, Internal Medicine, Accident and Emergency, Obstetrics and Gynaecology and Oncology. RESULTS: One hundred and forty-three (65%) of the targeted 220 physicians responded. There were 77 (55%) females and 41% of respondents were between ages 26 and 30 years. Knowledge of CPR guidelines was inadequate, as the median score obtained was 4.0 (interquartile range [IQR] 2-5) out of a possible eight. Physician seniority was inversely related to knowledge scores (p < 0.01). While 86% of all respondent physicians had been trained in BLS, only 46% were certified at the time of the study. Fewer (52%) were trained in ACLS with only 36% currently certified. Only 65% had been trained in the use of a defibrillator. Most knew the correct compression rate (78%), but only 46% knew the compressions to breaths ratio for both single and two-rescuer CPR. Only 42% of anaesthetists and 27% of emergency physicians were currently ACLS certified. CONCLUSION: Physician knowledge of CPR protocols was suboptimal and current certification levels were low. Increased training and recertification is necessary to improve physician knowledge which is expected to result in improved performance of CPR.

A Survey of the Pain Management of Acute Painful Crisis among Patients with Sickle Cell Disease at Two Centres in Jamaica.

OBJECTIVES: The aim of this survey was to establish the pain management approaches to acute painful crisis (APC) in sickle cell patients at two healthcare facilities and to compare with available guidelines. METHODS: A multi-centre observational survey of the management of APC in sickle cell patients was conducted. Data were collected at the Sickle Cell Unit (SCU), Tropical Medicine Research Institute (TMRI) and Accident and Emergency Department (A&E), University Hospital of the West Indies. RESULTS: One hundred episodes of uncomplicated APC involving 81 patients managed at the SCU clinic and 64 episodes at the A&E in a total of 28 patients were included in the data set. Drugs used at the SCU included oral morphine, codeine and paracetamol and intramuscular diclofenac. At the A&E, parenteral morphine and pethidine were most commonly used. At the SCU, the mean time to initiation of analgesics was 38 minutes (IQR 25 to 50 minutes); at the A&E, this was 111 minutes (IQR 50 to 150 minutes). At the SCU, the mean duration of stay (DOS) was 2.9 hours (IQR 1.9 to 3.8 hours) with 94% of the patients being discharged home. At the A&E, the mean DOS was 13.0 hours (IQR 8.3 to 16.9 hours) with 93% of the patients being discharged home. The A&E patient group contained multiple high frequency presenters. Documentation of pain severity scores was inconsistent. CONCLUSION: The findings of the survey indicate that the management of APC at the two centres is substantially different. Further study is required to investigate patient satisfaction, centre preference and analgesic therapy efficacy.

Blood use in neurosurgical cases at the university hospital of the west indies.

OBJECTIVE: Many neurosurgical cases are done without the need for blood transfusion, yet blood is unnecessarily cross-matched, resulting in wasted resources. This study was undertaken to document and compare the number of units of blood components requested, cross-matched and transfused in neurosurgical cases at the University Hospital of the West Indies (UHWI). METHODS: A prospective, observational study was undertaken over one year. Data collected for each patient included demographic information, relevant perioperative data, and blood banking data including blood components requested, cross-matched and transfused. Data were analysed using SPSS version 16. RESULTS: Data were analysed on 152 patients, 71 females (46.7%) and 81 males (53.3%). The mean age was 48.7 ± 19.6 years and 100 of the procedures were done electively (65.8%). Blood components were ordered in 114 (75%) cases, red cells more commonly in 113 (74.3%) patients, and plasma in 19 (12.5%) patients. Overall, 20 patients (13.2%) were transfused. Most patients (90.9%) needed one to two units of blood. Of the 236 units of blood components that were cross-matched or prepared, only 62 were transfused. The cross-match/preparation to transfusion ratio (CTR/PTR) was 6.00 for red cells and 1.31 for plasma. Preoperative haemoglobin ≤ 10.0 g/dL (p = 0.001), estimated blood loss of ≥ 1 litre (p < 0.001), higher American Society of Anesthesiologists (ASA) physical status score (p < 0.03) and a resident as lead surgeon (p < 0.05), were significant predictors of blood transfusion. CONCLUSION: The transfusion rate was low with a high cross-match to transfusion ratio, suggesting that less cross-matching is needed. A new approach to blood ordering for neurosurgical cases is recommended.

The role of pre-induction ketamine in the management of postoperative pain in patients undergoing elective gynaecological surgery at the University Hospital of the West Indies.

OBJECTIVES: To determine if a single preoperative dose of ketamine hydrochloride reduces the narcotic analgesic requirements and/or pain scores reported by patients in the first 24 hours postoperatively. METHODS: A single-centred, prospective, case-control study was conducted on 84 patients aged 18-65 years, American Society of Anaesthesiologists (ASA) I and II, undergoing elective gynaecological procedures at the University Hospital of the West Indies (UHWI). Patients were randomly assigned to one of two treatment groups: (a) ketamine group, where patients received intravenous ketamine 0.15 mg/kg pre-induction of anaesthesia; and (b) placebo group, patients received normal saline. The anaesthetic technique was standardized. Postoperatively, patients were interviewed at 15-minute intervals for the first hour then at 2, 4, 6, and 24 hours to determine their pain scores and any side effects. Timing and dose of opioid analgesics were also recorded. RESULTS: The mean cumulative morphine dose over the first 24 hours postoperatively was 29.6 +/- 10.8 mg for the ketamine group and 31.9 +/- 11.2 mg for the placebo group (p = 0.324). There was also no significant difference in pain intensity measured by the visual analogue scale (VAS) between the groups. Patient age and the type of surgery performed were not found to influence pain intensity. The most common adverse effects were nausea and vomiting (32.5%), dizziness (42.2%), drowsiness and sedation (45.8%) with no significant difference between groups. Both groups had an average in-hospital stay of three days postoperatively, however, the patients in the ketamine group reported higher satisfaction scores than those in the placebo group (p = 0.039). CONCLUSION: Despite no significant reduction in postoperative narcotic requirements or pain intensity, more patients who received ketamine reported higher levels of satisfaction with their pain management.

The impact of melt versus mechanical wear on the formation of pseudotachylyte veins in accretionary complexes.

Whether seismic rupture propagates over large distances to generate mega-earthquakes or is rapidly aborted mainly depends on the slip processes within the fault core, including particularly frictional melting or intense grain-size reduction and amorphization. The record of seismic slip in exhumed fault zones consists in many instances in Black Faults Rocks, dark and glass-like-filled aphanitic veins that have been interpreted as resulting from the quenching of frictional melts, i.e. pseudotachylytes. Such interpretation has nevertheless been questioned as similar macro to nano-microstructures have been observed either on intensely comminuted natural fault rocks or on slow creep experiments conducted on crustal rocks, where melting is absent. Here, we report a new dataset of Raman Spectroscopy of Carbonaceous Material analyses, aimed at discriminating the slip weakening processes operating in the fault core during slip. Using high spatial resolution profiles on natural Black Fault Rocks from exhumed accretionary complexes and an experimentally calibrated modelling of Raman intensity ratio evolution with temperature, we assessed different scenarios of temperature evolution during fault slip. None of them is able to account for the distribution of Raman signal, so that in the three studied Black Fault Rocks interpreted so far as natural pseudotachylytes, Raman Spectroscopy of Carbonaceous Material rather reflects the effect of intense and localized strain during fault slip. Furthermore, the absence of thermal imprint on Raman signal puts upper bounds on the temperature reached within the fault zone. If one cannot rule out the occurrence of high and short-lived temperature increase due to friction, the latter was not high enough as to melt the large quartz fraction of the fault zone rocks.

Anaesthetic morbidity at the University Hospital of the West Indies.

OBJECTIVE: There is little information on adverse anaesthetic outcomes from the Caribbean. The aim of this study was to investigate the occurrence of anaesthetic morbidity and mortality at the University Hospital of the West Indies (UHWI) and to identify possible risk factors. METHODS: All anaesthetic procedures at the UHWI were monitored for adverse events and patient outcomes for the 12-month period from March 2004 to February 2005. Possible risk factors for these adverse events were assessed using logistic regression. RESULTS: Of 3185 anaesthetic procedures, the incidence of intra-operative events was 201 per 1000 (95% CI 187, 215); 151 per 1000 being cardiovascular and 26 per 1000 respiratory. Others included excess blood loss and equipment failure, hyperglycaemia, nausea and vomiting. Patients with intraoperative complications were three times more likely to have complications during recovery (OR = 3.35; 95% CI 2.59, 4.33, p < 0.001). The incidence of complications among paediatric patients was 139 per 1000 (95% CI 104, 174) intra-operatively and 58 per 1000 (95% CI 34, 81) during recovery. Risk factors for developing complications (p < 0.05) included age > 50 years, ASA status > or = II, prolonged anaesthesia, high surgical risk, general or combined anaesthetic techniques, senior anaesthetist, intubated patients and co-morbidities. There were 14 operative mortalities, none of which was anaesthesia-related CONCLUSION: Anaesthetic complication rates at the UHWI are comparable to those in developed countries, except for higher paediatric complication rates and ICU admissions and lower rates of postoperative nausea and vomiting.

Surgical and intensive care needs of head-injured patients transferred to the University Hospital of the West Indies.

A cross-sectional, descriptive study utilizing data collected in the 'Trauma Registry' of the Department of Surgery, Radiology, Anaesthesia and Intensive Care at the University Hospital of the West Indies (UHWI) was undertaken to document injury severity, surgical requirements and intensive care needs of head-injured patients transferred to the UHWI over a three-year period Of 144 patients studied, the majority (71%) were young males. Overall, injury tended to be mild Twenty-three patients (16.0%) had severe head injury and 27 patients (18.8%) were admitted to the intensive care unit. Concussion with (33%) or without (36%) skull fracture was the commonest neurological admission diagnosis. Associated non-neurological injuries in 33% were primarily fractures. Fifty-six patients (39%) required surgical intervention. Craniotomies and open reduction and internal fixation of fractures were the commonest procedures. The majority of patients (79.2%) were discharged home; 56 (39%) made a good Glasgow outcome score recovery. Seventeen patients (11.8%) died in hospital. As most of the transferred patients with head injuries in this study had only mild injury, most commonly concussions, and their prognosis was good, we recommend that appropriate educational and training programmes and transfer policies be implemented to minimize inappropriate transfers.

Triage decisions and outcome among the critically ill at the University Hospital of the West Indies.

The worldwide scarcity of intensive care therapy leads to the rationing of this expensive resource. This prospective study investigates the rationing of intensive therapy at the University Hospital of the West Indies (UHWI) by recording triage decisions for intensive care unit (ICU) admission and the impact of these decisions on patient outcome. Between June 2001 and May 2002, all patients triaged for admission to a multidisciplinary ICU were studied For each patient, data were collected including APACHE II score, ICU resource availability and patient survival. There were 356 eligible requests, and 285 (80%) were admitted to the ICU, with 73 (26%) of these admitted patients receiving intensive care outside of the ICU due to space limitations. The APACHE II score was the strongest predictor of ICU admission, with admission more likely as the score decreased (odds ratio = 0.94, 95% confidence interval 0.91, 0.98, p = 0.001). Of 311 requests considered suitable for admission, 26 (8%) were refused admission due to resource limitations. Mortality among these eligible refusals was 81%, compared to 34% among admitted patients (p < 0.001). Although triage decisions are based predominantly on a patient's disease severity, the demand for ICU space exceeds supply, and patient care is negatively impacted by this imbalance.

Neurogenesis in adult insect mushroom bodies.

The occurrence of neurogenesis in mushroom bodies of adult insects belonging to several orthopteroid and coleopteran families is described. Using injections of 5-bromo, T2'-deoxyuridine, we showed that neuroblasts, which are progenitors of Kenyon cells during preimaginal instars, continue to divide in adult Acheta domesticus. Their progeny constitute a central column in mushroom body cortices of 3-week-old females. Other Gryllidae, Gryllus bimaculatus and Gryllomorpha dalmatina, show the same pattern of neuroblast activity and migration of their progeny. Immunocytochemical staining of glial cells failed to reveal any immunoreactivity, either in proliferating regions or in the resulting cells. In another orthopteran, Locusta migratoria, discrete clusters of cells, located dorsolateral to the Kenyon cells, incorporated 5-bromo, 2'-deoxyuridine, but we could not detect any neuronal progeny migrating to the mushroom body cortices. These cells were strongly labeled with an antiglial antibody, indicating that the replicating cells are glioblasts rather than neuroblasts. In Periplaneta americana (Dictyoptera), cells replicating their DNA were similarly shown to immunoreact with glial antibodies. In contrast, three coleopterans (Tenebrio molitor, Zophobas species, Harmonia axyridis) have two large neuroblasts located in the middle of the mushroom body cortices. These produce cells which migrate within the group of Kenyon cells, their nuclei having the same shape and size as those of surrounding Kenyon cells. In adult insects, neurogenesis in mushroom bodies occurs in Gryllidae and several coleopteran families, but could not be demonstrated in Dictyoptera and Acrididae. Its occurrence and distribution raise the issue of unexpected plasticity in the adult insect brain.

Biochemical and histological changes in the brain of the cricket Nemobius sylvestris infected by the manipulative parasite Paragordius tricuspidatus (Nematomorpha).

Hairworms (nematomorpha) alter the behaviour of their insect hosts, making them commit 'suicide' by jumping into an aquatic environment required by the adult parasite for the continuation of its life cycle. To explore the physiological and neuronal basis of this behavioural manipulation, we first performed a biochemical study to quantify different neurotransmitters or neuromodulators (monoamines and amino acids) in the brain of crickets (Nemobius sylvestris) uninfected and infected by the hairworm Paragordius tricuspidatus. We also analysed several polyamines and amino-acids having no known neuromodulatory function. The presence/absence of the parasite explained the largest part of the variation in compound concentrations, with infected individuals displaying on average lower concentrations than uninfected individuals. However, for three amino acids (taurine, valine and tyrosine), a significant part of the variation was also correlated with the manipulative process. In order to compare neurogenesis between infected and uninfected crickets, we also performed a histological study on mushroom bodies in the cricket's brain. The mitotic index exhibited a two-fold increase in infected crickets as compared with uninfected crickets. This is the first study to document changes in the brain of insects infected by nematomorphs.

Inhibition of polyamine biosynthesis alters oviposition behavior in female crickets.

The role of polyamines in the expression of cricket oviposition, a juvenile hormone-dependent behavior, was investigated using a specific inhibitor of ornithine decarboxylase, alpha-difluoromethylornithine (alpha-DFMO). The fat body of treated female house crickets (Acheta domesticus) did not show any putrescine and presented reduced levels of spermidine, whereas spermine titres were significantly enhanced. In nervous tissue, alpha-DFMO did not affect spermine titres but induced a severe drop in spermidine levels. In polyamine depleted females, the expression of egg-laying behavior was delayed and was expressed less frequently compared with controls. As drug treatment did not seem to affect juvenile hormone titres, the data suggest that juvenile hormone might act on behavior by way of polyamine metabolism. These results support the view that, in insects, as in vertebrates, the ornithine decarboxylase-polyamine system is involved in the maturation of complex behaviors.

In vivo application of HRP crystals: a new and efficient method for tracing neural connections in insects.

Solid HRP pellets prepared with a 2.5% Triton X-100 aqueous solution were implanted either into corpora allata or applied onto neurohemal organs of a cricket. The method presents two advantages: it allows one to perform "in vivo" instead of "in vitro" experiments, and detergent HRP pellets are easy to manipulate. Thus, this method combines simplicity with accuracy and appears to be very useful in tracing neural connections in the insect nervous system.

Blood use in neurosurgical cases at the University Hospital of the West Indies / El uso de la sangre en los casos de neurocirugía en el Hospital Universitario de West Indies

OBJECTIVE: Many neurosurgical cases are done without the need for blood transfusion, yet blood is unnecessarily cross-matched, resulting in wasted resources. This study was undertaken to document and compare the number of units of blood components requested, cross-matched and transfused in neurosurgical cases at the University Hospital of the West Indies (UHWI). METHODS: A prospective, observational study was undertaken over one year. Data collected for each patient included demographic information, relevant perioperative data, and blood banking data including blood components requested, cross-matched and transfused. Data were analysed using SPSS version 16. RESULTS: Data were analysed on 152 patients, 71 females (46.7%) and 81 males (53.3%). The mean age was 48.7 ± 19.6 years and 100 of the procedures were done electively (65.8%). Blood components were ordered in 114 (75%) cases, red cells more commonly in 113 (74.3%) patients, and plasma in 19 (12.5%) patients. Overall, 20 patients (13.2%) were transfused. Most patients (90.9%) needed one to two units of blood. Of the 236 units of blood components that were cross-matched or prepared, only 62 were transfused. The cross-match/preparation to transfusion ratio (CTR/PTR) was 6.00 for red cells and 1.31 for plasma. Preoperative haemoglobin < 10.0 g/dL (p = 0.001), estimated blood loss of > 1 litre (p < 0.001), higher American Society of Anesthesiologists (ASA) physical status score (p < 0.03) and a resident as lead surgeon (p < 0.05), were significant predictors of blood transfusion. CONCLUSION: The transfusion rate was low with a high cross-match to transfusion ratio, suggesting that less cross-matching is needed. A new approach to blood ordering for neurosurgical cases is recommended.

OBJETIVO: Muchos casos neuroquirurgicos se realizan sin necesidad de transfusion de sangre. Sin embargo, la sangre es innecesariamente sometida a pruebas cruzadas, lo cual resulta en un malgasto de recursos. Este estudio fue emprendido con el proposito de documentar y comparar el numero de unidades de los componentes sanguineos requeridos, cotejados, y transfundidos en los casos de neurocirugia en el Hospital Universitario de West Indies (HUWI). MÉTODOS: Se realizo un estudio prospectivo observacional por espacio de mas de un ano. Los datos recopilados de cada paciente incluian informacion demografica, datos relevantes perioperatorios, y datos de bancos de sangre, incluyendo los componentes sanguineos solicitados, cotejados, y transfundidos. Los datos fueron analizados utilizando SPSS version 16. RESULTADOS: Los datos se analizaron en 152 pacientes: 71 mujeres (46.7%) y 81 varones (53.3%). La edad promedio fue de 48.7 ± 19.6 anos y 100 de los procedimientos se realizaron de manera electiva (65.8%). Se ordenaron componentes de la sangre en 114 casos (75%), siendo los globulos rojos los mas comunmente requeridos en 113 pacientes (74,3%) y el plasma en 19 pacientes (12.5%). En general, 20 pacientes (13.2%) fueron transfundidos. La mayoria de los pacientes (90.9%) necesito una o dos unidades de sangre. De las 236 unidades de componentes sanguineos que fueron preparados o sometidos a pruebas cruzadas, solo 62 fueron transfundidos. La proporcion de la preparacion/prueba cruzada en relacion con la transfusion (CTR/PTR por sus siglas en ingles) fue 6.00 para los globulos rojos y 1.31 para el plasma. La hemoglobina preoperatoria < 10.0 g/dL (p = 0.001), la perdida estimada de sangre de > 1 litro (p < 0.001), la mayor puntuacion del estado fisico (p < 0.03) segun los criterios de la Sociedad Americana de Anestesiologos (ASA), y un residente como principal cirujano (p < 0.05), fueron predictores significativos de la transfusion de sangre. CONCLUSIÓN: La tasa de transfusion fue baja, con una alta proporcion de la prueba cruzada frente a la transfusion, sugiriendo que se necesitan menos pruebas cruzadas. Se recomienda un nuevo enfoque a la hora de hacer pedidos de sangre para los casos neuroquirurgicos.

The role of pre-induction ketamine in the management of postoperative pain in patients undergoing elective gynaecological surgery at the University Hospital of the West Indies / El papel de la ketamina de pre-inducción en el tratamiento del dolor postoperatorio en pacientes que se someten a cirugía ginecológica electiva en el Hospital Universitario de West Indies

OBJECTIVES: To determine if a single preoperative dose of ketamine hydrochloride reduces the narcotic analgesic requirements and/or pain scores reported by patients in the first 24 hours postoperatively. METHODS: A single-centred, prospective, case-control study was conducted on 84 patients aged 18-65 years, American Society of Anaesthesiologists (ASA) I and II, undergoing elective gynaecological procedures at the University Hospital of the West Indies (UHWI). Patients were randomly assigned to one of two treatment groups: (a) ketamine group, where patients received intravenous ketamine 0.15 mg/kg pre-induction of anaesthesia; and (b) placebo group, patients received normal saline. The anaesthetic technique was standardized. Postoperatively, patients were interviewed at 15-minute intervals for the first hour, then at 2, 4, 6, and 24 hours to determine their pain scores and any side effects. Timing and dose of opioid analgesics were also recorded. RESULTS: The mean cumulative morphine dose over the first 24 hours postoperatively was 29.6 ±10.8 mg for the ketamine group and 31.9 ± 11.2 mg for the placebo group (p = 0.324). There was also no significant difference in pain intensity measured by the visual analogue scale (VAS) between the groups. Patient age and the type of surgery performed were not found to influence pain intensity. The most common adverse effects were nausea and vomiting (32.5%), dizziness (42.2%), drowsiness and sedation (45.8%) with no significant difference between groups. Both groups had an average in-hospital stay of three days postoperatively, however, the patients in the ketamine group reported higher satisfaction scores than those in the placebo group (p = 0.039). CONCLUSION: Despite no significant reduction in postoperative narcotic requirements or pain intensity, more patients who received ketamine reported higher levels of satisfaction with their pain management.

OBJETIVOS: Determinar si una sola dosis preoperativa de hidrocloruro de ketamina reduce los requerimientos de analgésicos narcóticos y/o puntuaciones de dolor reportados por los pacientes en las primeras 24 horas posteriores a la operación. MÉTODOS: Se llevó a cabo un estudio de caso-control, prospectivo, monocéntrico en 84 pacientes de 18-65 anos de edad, sometidas a procedimientos de ginecologia electiva en el Hospital Universitario de West Indies (HUWI). Los pacientes fueron asignados aleatoriamente a uno de dos grupos de tratamiento: (a) grupo ketamina, en el que los pacientes recibieron una preinducción de anestesia de 0.15 mg/kg de ketamina intravenosa; y (b) grupo placebo, en el que los pacientes recibieron una solución salina normal. La técnica anestésica fue estandarizada. Postoperatoriamente, se entrevis-taron los pacientes a intervalos de 15 minutos durante la primera hora, y más tarde a 2, 4, 6, y 24 horas para determinar sus puntuaciones de dolor, y efectos cualesquiera. También se registraron el tiempo y la dosificación de los analgésicos. RESULTADOS: La dosis promedio de morfina cumulativa promedio en las primeras 24 horas posteriores a la operación, fue de 29.6 ± 10.8 mg para el grupo de ketamina; y 31.9 ± 11.2 mg para el grupo placebo (p = 0.324). No hubo tampoco ninguna diferencia significativa entre los grupos, en cuanto la intensidad de dolor medida mediante la escala visual analógica (EVA). No se halló que la edad del paciente y el tipo de cirugia realizada tuvieran influencia en la intensidad de dolor. Los efectos adversos más comúnes fueron náusea y vómito (32.5%), vértigo (42.2%), adormecimiento y sedación (45.8%), sin diferencia significativa entre los grupos. Ambos grupos tuvieron una estancia intra-hospitalaria promedio de tres dias tras la operación. No obstante, los pacientes del grupo de la ketamina reportaron puntuaciones de mayor satisfacción que los del grupo placebo (p = 0.039). CONCLUSIÓN: Si bien no hubo una reducción significativa en cuanto a requerimientos de narcóticos o intensidad de dolor postoperatorios, más pacientes que recibieron ketamina reportaron niveles más altos de satisfacción con el tratamiento del dolor.

Physiological approach to the onset of receptivity in female Acheta domesticus. I. Role of the corpora allata and ovaries.

During the 32 hr following the imaginal moult, all female Acheta domesticus actively or passively refuse male courtship; they are unreceptive. As of 32 hr, the most precocious females become receptive and accept mating. At this time, juvenile hormone (JH III) synthesized by corpora allata (CA) is already detectable in hemolymph, while ecdysteroids (synthesized by ovaries) begin increasing at 48 hr. JH III and ecdysteroid levels in hemolymph were measured by RIA. After allatectomy and/or ovariectomy, all females became receptive, thus showing that CA and/or ovaries are not essential to the onset of receptivity. However, male courtship is longer for allatectomized females; in ovariectomized females, mating is delayed.

Specific requirement of putrescine for the mitogenic action of juvenile hormone on adult insect neuroblasts.

Persistent neurogenesis in an adult insect brain was recently shown to be stimulated by juvenile hormone (JH). This morphogenetic hormone was also shown to act on polyamine biosynthesis. To analyze the possible involvement of polyamines in the neurogenic action of JH, two series of experiments were carried out with adult female crickets, Acheta domesticus: (i) inhibition of the first key enzyme in polyamine biosynthesis, ornithine decarboxylase, with alpha-difluoromethylornithine (alpha-DFMO), and examination of the effects of this treatment on the neuroblast proliferation response to JH; and (ii) examination of the effects of putrescine supplementation on the mitotic index of JH-deprived and alpha-DFMO-treated females. In control females, alpha-DFMO treatment, as well as JH deprivation, greatly reduced neuroblast proliferation. Putrescine supplementation in alpha-DFMO-treated insects overcame the effects of alpha-DFMO, and allowed for detection of putrescine in the neural tissue and stimulation of brain neurogenesis. In JH-deprived females, alpha-DFMO treatment completely prevented the stimulatory action of JH on neuroblast proliferation and on brain putrescine levels. By contrast, putrescine feeding of JH-deprived animals was able to mimic the stimulatory effect of JH: brain putrescine levels increased and neuroblast proliferation was restored. To our knowledge, this report demonstrates for the first time that in vivo administration of putrescine can mimic the effects of a morphogenetic hormone on adult neuroblast proliferation, and shows the importance of polyamines, especially putrescine, in the transduction of JH message in neural tissue.

Immunocytochemical mapping of an RDL-like GABA receptor subunit and of GABA in brain structures related to learning and memory in the cricket Acheta domesticus.

The distribution of putative RDL-like GABA receptors and of gamma-aminobutyric acid (GABA) in the brain of the adult house cricket Acheta domesticus was studied using specific antisera. Special attention was given to brain structures known to be related to learning and memory. The main immunostaining for the RDL-like GABA receptor was observed in mushroom bodies, in particular the upper part of mushroom body peduncle and the two arms of the posterior calyx. Weaker immunostaining was detected in the distal part of the peduncle and in the alpha and beta lobes. The dorso- and ventrolateral protocerebrum neuropils appeared rich in RDL-like GABA receptors. Staining was also detected in the glomeruli of the antennal lobe, as well as in the ellipsoid body of the central complex. Many neurons clustered in groups exhibit GABA-like immunoreactivity. Tracts that were strongly immunostained innervated both the calyces and the lobes of mushroom bodies. The glomeruli of the antennal lobe, the ellipsoid body, as well as neuropils of the dorso- and ventrolateral protocerebrum were also rich in GABA-like immunoreactivity. The data demonstrated a good correlation between the distribution of the GABA-like and of the RDL-like GABA receptor immunoreactivity. The prominent distribution of RDL-like GABA receptor subunits, in particular areas of mushroom bodies and antennal lobes, underlines the importance of inhibitory signals in information processing in these major integrative centers of the insect brain.

Arginase expression in peritoneal macrophages and increase in circulating polyamine levels in mice infected with Schistosoma mansoni.

We investigated the nitric oxide (NO) synthase and arginase pathways in resident peritoneal macrophages of mice infected with the tropical parasite Schistosoma mansoni. The two enzymes may have opposite effects, insofar as NO may be involved in the killing of the parasite whereas arginase may stimulate parasite growth via polyamine synthesis. We determined the effects of the infection on the expression and activity of the two enzymes in macrophages, before and after cytokine activation. Cells from infected mice expressed the hepatic type I arginase, whereas in control cells, the enzyme was expressed only after cytokine activation, as were NO synthase II and type II arginase in both groups of cells. Moreover, we found that in infected mice, arginase expression in macrophages was associated with a ten fold increase in the concentration of circulating ornithine-derived polyamines. This may be of pathological importance, since parasitic helminths are though to be dependent on their hosts for the uptake and interconversion of polyamines.