Maternal effects are long-lasting and influence female offspring's reproductive strategy in the swordtail fish Xiphophorus multilineatus.

The adaptive benefits of maternal investment into individual offspring (inherited environmental effects) will be shaped by selection on mothers as well as their offspring, often across variable environments. We examined how a mother's nutritional environment interacted with her offspring's nutritional and social environment in Xiphophorus multilineatus, a live-bearing fish. Fry from mothers reared on two different nutritional diets (HQ=high quality and LQ=low quality) were all reared on a LQ diet in addition to being split between two social treatments: exposed to a large adult male during development and not exposed. Mothers raised on a HQ diet produce offspring that were not only initially larger (at 14 days of age), but grew faster, and were larger at sexual maturity. Male offspring from mothers raised on both diets responded to the exposure to courter males by growing faster; however, the response of their sisters varied with mother's diet; females from HQ diet mothers reduced growth if exposed to a courter male, whereas females from LQ diet mothers increased growth. Therefore, we detected variation in maternal investment depending on female size and diet, and the effects of this variation on offspring were long-lasting and sex specific. Our results support the maternal stress hypothesis, with selection on mothers to reduce investment in low-quality environments. In addition, the interaction we detected between the mother's nutritional environment and the female offspring's social environment suggests that female offspring adopted different reproductive strategies depending on maternal investment.

Hot or not? The 10% rule in sentinel lymph node biopsy for malignant melanoma revisited.

BACKGROUND: The surgeon needs a practical rule to follow when deciding whether to excise a lymph node during sentinel node biopsy (SLNB). The "10% rule" dictates that all nodes with a radiation count of greater than 10% of the hottest node and all blue nodes should be removed, and this study observes the effects of following this rule in SLNB in melanoma. METHODS: We reviewed the records of 665 patients with primary melanoma who underwent sentinel lymph node over a 5-year period (2007-2011). RESULTS: 2064 nodes were identified in 898 nodal basins in 665 patients. 141 (21%) patients had at least one positive sentinel node. 105 positive nodal basins were identified in which more than one sentinel node was removed. In 18 of these, a less radioactive node was positive for tumour when the most radioactive node was negative. Of 175 positive nodes 157 (90%) contained blue dye staining. For cases in which the positive sentinel node was not the hottest node, the positive node had apparent blue dye staining in all 18 cases (100%), and was the second hottest node in the basin. CONCLUSION: In this series removing just the hottest node and all blue nodes would not have missed a single positive basin and would have resulted in a 38% reduction in the number of nodes removed compared to those taken following the 10% rule, without changing the staging in any patient.

An assessment of burn care professionals' attitudes to major burn.

The resuscitation of severe burn remains a controversial area within the burn care profession. There is ongoing debate as to what percentage burn is associated with a sufficient quality of life to support initial resuscitation efforts. We conducted a survey of delegates at the 39th Annual Meeting of the British Burns Association (2005), regarding attitudes towards resuscitation following major burns. Respondents were asked the maximum percentage total body surface area (TBSA) burn beyond which they would not wish to be resuscitated. They were also asked what maximum TBSA they perceived to be commensurate with an acceptable quality of life (QOL). One hundred and forty three of 300 delegates responded to the questionnaire. Thirty three percent of respondents would not wish to be resuscitated with 50-75% TBSA burns or greater. A further 35% would not wish to have life-sustaining intervention with 75-95% TBSA burns or greater. The remaining 32% indicated that they would not want resuscitation with TBSA burns>95%. Regardless of TBSA affected, 16% would not wish resuscitation if they had full thickness facial burns, a further 10% did not want resuscitation if both their hands and faces were affected. Our survey demonstrates the diversity of personal preference amongst burn care professionals. This would suggest that a unifying philosophy regarding the resuscitation of extensive burns will remain elusive.

Sestamibi scan-directed, minimally invasive video-assisted parathyroidectomy: an effective treatment for solitary parathyroid adenoma.

BACKGROUND: Solitary adenomas have been shown to be responsible for almost 90% of cases of primary hyperparathyroidism. AIM: The purpose of this study was to determine the utility of sestamibi scanning pre-operatively to guide minimally invasive video-assisted (MIVA) parathyroidectomy. METHODS: We reviewed 40 patients who underwent parathyroidectomy between 2003 and 2004. All patients underwent a pre-operative sestamibi scan. RESULTS: Thirty-three (82%) patients had a localized solitary adenoma on sestamibi scan. Of these patients 29 underwent attempted MIVA parathyroidectomy. MIVA parathyroidectomy was successful in 22 patients. When pre-operative sestamibi scanning was correlated with pathological diagnosis it was shown to have a sensitivity of 82% and positive predictive value of 94%. CONCLUSION: Pre-operative sestamibi scan localization of a parathyroid adenoma offers a 94% positive predictive value for adenoma location. This facilitates MIVA parathyroidectomy to be used effectively to treat primary hyperparathyroidism in the majority of patients.

Postdisaster stress in the United States and Mexico: a cross-cultural test of the multicriterion conceptual model of posttraumatic stress disorder.

Data on symptoms of posttraumatic stress disorder (PTSD) were collected 6 months after Hurricanes Paulina (N = 200; Mexico) and Andrew (non-Hispanic n = 270; United States) using the Revised Civilian Mississippi Scale. A 4-factor measurement model that represented the accepted multicriterion conceptualization of PTSD fit the data of the U.S. and Mexican samples equally well. The 4 factors of Intrusion, Avoidance, Numbing, and Arousal correlated significantly and equivalently with severity of trauma in each sample. A single construct explained much of the covariance of the symptom factors in each sample. However, modeling PTSD as a unidimensional construct masked differences between samples in symptom severity. With severity of trauma controlled, the Mexican sample was higher in Intrusion and Avoidance, whereas the U.S. sample was higher in Arousal. The results suggest that PTSD is a meaningful construct to study in Latin American societies.

The neuronal basis of feeding in the snail, Helisoma, with comparisons to selected gastropods.

Research on identified neurons during the last quarter century was forecast at a conference in 1973 that discussed "neuronal mechanisms of coordination in simple systems." The focus of the conference was on the neuronal control of simple stereotyped behavioral acts. Participants discussing the future of such research called for a comparative approach; emphasis on structure-function interactions; attention to environmental and behavioral context; and the development of new techniques. Significantly, in some cases amazing progress has been made in these areas. Major conclusions of the last quarter century are that so-called simple behaviors and the neural circuitry underlying them tend to be less simple, more flexible, and more highly modulated than originally imagined. However, the comparative approach has, as yet, failed to reach its potential. Molluscan preparations, along with arthropods and annelids, have always been at the forefront of neuroethological studies. Circuitry underlying feeding has been studied in a handful of species of gastropod molluscs. These studies have contributed substantially to our understanding of sensorimotor organization, the hierarchical control of behavior and coordination of multiple behaviors, and the organization and modulation of central pattern generators. However, direct interspecific comparisons of feeding circuitry and potentially homologous neurons have been lacking. This is unfortunate because much of the vast radiation of the class Gastropoda is associated with variations in feeding behaviors and feeding apparatuses, providing ample substrates for comparative studies including the evolution of defined circuitry. Here, the neural organization of feeding in the snail, Helisoma, is examined critically. Possible direct interspecific comparisons of neural circuitry and potentially homologous neurons are made. A universal model for central pattern generators underlying rasping feeding is proposed. Future comparative studies can be expected to combine behavioral, morphological, electrophysiological, molecular and genetic techniques to identify neurons and define neural circuitry. Digital resources will undoubtedly be exploited to organize and interface databases allowing illumination of the evolution of homologous identified neurons and defined neural circuitry in the context of behavioral change.

A qualitative analysis of posttraumatic stress among Mexican victims of disaster.

In unstructured interviews, 24 Mexicans described survivors' responses to disasters in Guadalajara, Jalisco (n = 9), Homestead, Florida (n = 6), and Puerto Angel, Oaxaca (n = 9). This analysis assessed the extent to which symptom descriptions corresponded to the 17 criterion symptoms of PTSD. Nineteen participants (79%) mentioned from 1 to 9 criterion symptoms. Event-related distress, hypervigilance, recurrent recollections, and avoiding reminders were described most often. Only 3 criterion symptoms were never described. Twenty participants (83%) provided 109 separate expressions that could not be classified specifically as criterion symptoms. These phrases were sorted by 9 independent Mexican volunteers and cluster analyzed. Clusters composed of ataques de nervios, depression, lasting trauma, and somatic complaints provided the best description of the data.

Alternative oxidase inhibitors potentiate the activity of atovaquone against Plasmodium falciparum.

Recent evidence suggests that the malaria parasite Plasmodium falciparum utilizes a branched respiratory pathway including both a cytochrome chain and an alternative oxidase. This branched respiratory pathway model has been used as a basis for examining the mechanism of action of two antimalarial agents, atovaquone and proguanil. In polarographic assays, atovaquone immediately reduced the parasite oxygen consumption rate in a concentration-dependent manner. This is consistent with its previously described role as an inhibitor of the cytochrome bc1 complex. Atovaquone maximally inhibited the rate of P. falciparum oxygen consumption by 73% +/- 10%. At all atovaquone concentrations tested, the addition of the alternative oxidase inhibitor, salicylhydroxamic acid, resulted in a further decrease in the rate of parasite oxygen consumption. At the highest concentrations of atovaquone tested, the activities of salicylhydroxamic acid and atovaquone appear to overlap, suggesting that at these concentrations, atovaquone partially inhibits the alternative oxidase as well as the cytochrome chain. Drug interaction studies with atovaquone and salicylhydroxamic acid indicate atovaquone's activity against P. falciparum in vitro is potentiated by this alternative oxidase inhibitor, with a sum fractional inhibitory concentration of 0.6. Propyl gallate, another alternative oxidase inhibitor, also potentiated atovaquone's activity, with a sum fractional inhibitory concentration of 0.7. Proguanil, which potentiates atovaquone activity in vitro and in vivo, had a small effect on parasite oxygen consumption in polarographic assays when used alone or in the presence of atovaquone or salicylhydroxamic acid. This suggests that proguanil does not potentiate atovaquone by direct inhibition of either branch of the parasite respiratory chain.

Metabolic changes of the malaria parasite during the transition from the human to the mosquito host.

Plasmodium falciparum is an obligate human parasite that is the causative agent of the most lethal form of human malaria. Transmission of P. falciparum to a new human host requires a mosquito vector within which sexual replication occurs. P. falciparum replicates as an intracellular parasite in man and as an extracellular parasite in the mosquito, and it undergoes multiple developmental changes in both hosts. Changes in the environment and the activities of parasites in these various life-cycle stages are likely to be reflected in changes in the metabolic needs and capabilities of the parasite. Most of our knowledge of the metabolic capabilities of P. falciparum is derived from studies of the asexual erythrocytic cycle of the parasite, the portion of the parasite life cycle found in infected humans that is responsible for malarial symptoms. Efforts to control transmission and to understand the sometimes unique biology of this parasite have led to information about the metabolic capabilities of sexual and/or sporogonic stages of these parasites. This review focuses on comparing and contrasting the carbohydrate, nucleic acid, and protein synthetic capabilities of asexual erythrocytic stages and sexual stages of P. falciparum.

Plasmodium falciparum: cyanide-resistant oxygen consumption.

It has been hypothesized that Plasmodium parasites utilize a branched chain respiratory pathway, consisting of a classical cyanide-sensitive branch and an alternative cyanide-resistant branch. To further explore this hypothesis, the effect of cyanide on Plasmodium falciparum was determined using a polarographic assay. The rate of oxygen consumption by saponin-freed parasites was approximately 5% that of control human white blood cells or of Toxoplasma gondii, consistent with an anabolic role for P. falciparum respiration. However, while all of the oxygen consumption of the control white blood cells and of T. gondii could be inhibited by cyanide, 25% of the oxygen consumption of the P. falciparum parasites was found to be insensitive to high concentrations of cyanide. The cyanide-resistant portion of the parasite oxygen consumption was completely inhibited by two inhibitors of alternative oxidase activities in other systems, propyl gallate and salicyclhydroxamic acid. These studies provide the first direct evidence for a branched chain respiratory pathway in P. falciparum. Furthermore, salicyclhydroxamic acid, propyl gallate, and related inhibitors of alternative oxidase activities were shown to inhibit the growth of P. falciparum in vitro. These results support the need for further investigation of alternative oxidase activity as an antimalarial chemotherapeutic target.

Feeding stimulants activate an identified dopaminergic interneuron that induces the feeding motor program in Helisoma.

The neurotransmitter dopamine is shown to play a fundamental role in the generation of the feeding motor pattern and resultant feeding behavior in Helisoma. Application of exogenous dopamine triggered the fictive feeding motor pattern in the isolated CNS and triggered feeding movements in semi-intact preparations. Application of feeding stimulants to the oral cavity excited the putatively dopaminergic buccal interneuron N1a, and depolarization of interneuron N1a triggered the production of the fictive feeding motor pattern. The ability of dopamine superfusion and of interneuron N1a stimulation to activate the fictive feeding motor pattern was blocked by the dopamine antagonist sulpiride. The phase of the fictive feeding motor pattern was reset by brief hyperpolarization of interneuron N1a, demonstrating that interneuron N1a is an integral component of the buccal central pattern generator (CPG). During spontaneous fictive feeding patterns, prolonged hyperpolarizations of interneuron N1a inhibited the production of patterned activity. Exogenous dopamine maintained the fictive feeding motor pattern in the absence of interneuron N1a activity. Interneuron N1a was labeled by the formaldehyde-glutaraldehyde histochemical technique, which is indicative of the presence of dopamine in mollusks. These data suggest that interneuron N1a is an endogenous source of the neuromodulator dopamine, intrinsic to the buccal CPG, and that interneuron N1a has a prominent role in the sensory-motor integration triggering the consummatory response.

Plasticity in the multifunctional buccal central pattern generator of Helisoma illuminated by the identification of phase 3 interneurons.

1. The mechanism for generating diverse patterns of buccal motor neuron activity was explored in the multifunctional central pattern generator (CPG) of Helisoma. The standard pattern of motor neuron activity, which results in typical feeding behavior, consists of three distinct phases of buccal motor neuron activity. We have previously identified CPG interneurons that control the motor neuron activity during phases 1 and 2 of the standard pattern. Here we identify a pair of interneurons responsible for buccal motor neuron activity during phase 3, and examine the variability in the interactions between this third subunit and other subunits of the CPG. 2. During the production of the standard pattern, phase 3 excitation in many buccal motor neurons follows a prominent phase 2 inhibitory postsynaptic potential. Therefore phase 3 excitation was previously attributed to postinhibitory rebound (PIR) in these motor neurons. Two classes of observations indicated that PIR was insufficient to account for phase 3 activity, necessitating phase 3 interneurons. 1) A subset of identified buccal neurons is inhibited during phase 3 by discrete synaptic input. 2) Other identified buccal neurons display discrete excitation during both phases 2 and 3. 3. A bilaterally symmetrical pair of CPG interneurons, named N3a, was identified and characterized as the source of phase 3 postsynaptic potentials in motor neurons. During phase 3 of the standard motor pattern, interneuron N3a generated bursts of action potentials. Stimulation of N3a, in quiescent preparations, evoked a depolarization in motor neurons that are excited during phase 3 and a hyperpolarization in motor neurons that are inhibited during phase 3. Hyperpolarization of N3a during patterned motor activity eliminated both phase 3 excitation and inhibition. Physiological and morphological characterization of interneuron N3a is provided to invite comparisons with possible homologues in other gastropod feeding CPGs. 4. These data support a model proposed for the organization of the tripartite buccal CPG. According to the model, each of the three phases of buccal motor neuron activity is controlled by discrete subsets of pattern-generating interneurons called subunit 1 (S1), subunit 2 (S2), and subunit 3 (S3). The standard pattern of buccal motor neuron activity underlying feeding is mediated by an S1-S2-S3 sequence of CPG subunit activity. However, a number of "nonstandard" patterns of buccal motor activity were observed. In particular, S2 and S3 activity can occur independently or be linked sequentially in rhythmic patterns other than the standard feeding pattern. Simultaneous recordings of S3 interneuron N3a with effector neurons indicated that N3a can account for phase-3-like postsynaptic potentials (PSPs) in nonstandard patterns. The variety of patterns of buccal motor neuron activity indicates that each CPG subunit can be active in the absence of, or in concert with, activity in any other subunit. 5. To explore how CPG activity may be regulated to generate a particular motor pattern from the CPG's full repertoire, we applied the neuromodulator serotonin. Serotonin initiated and sustained the production of an S2-S3 pattern of activity, in part by enhancing PIR in S3 interneuron N3a after the termination of phase 2 inhibition.

An identified glutamatergic interneuron patterns feeding motor activity via both excitation and inhibition.

1. Previously we demonstrated that glutamate is an important neurotransmitter in the CNS of Helisoma. Exogenous glutamate applied to the buccal ganglia mimicked both the excitatory and inhibitory effects of subunit 2 (S2) of the tripartite central pattern generator (CPG) on S2 postsynaptic motor neurons. Here we identify buccal interneuron B2 as an S2 interneuron by utilizing a combination of electrophysiology, pharmacology, and intracellular staining. In addition, neurons that were electrophysiologically and morphologically characterized as neuron B2 demonstrated antiglutamate immunoreactivity, suggesting that neuron B2 is a source of endogenous glutamate in the buccal ganglia. 2. Depolarization of neuron B2 evoked excitatory postsynaptic potentials in motor neurons excited by S2. The excitatory effects of B2 depolarization and S2 activation were reversibly antagonized by the ionotropic glutamate receptor antagonist 6-cyano-7-nitro-quinoxaline-2,3-dione, similar to the antagonism shown previously for application of exogenous glutamate. Depolarization of neuron B2 also evoked inhibitory postsynaptic potentials in motor neurons inhibited by S2. When such motor neurons were maintained in isolated cell culture, application of exogenous glutamate produced a direct hyperpolarization of the membrane potential. 3. The activity of neuron B2 is necessary for the production of the standard pattern of buccal motor neuron activity, which underlies functional feeding movements. The subunits of the tripartite buccal CPG must be active in the temporal sequence S1-S2-S3 to produce the standard feeding pattern. Rhythmic inhibition from neuron B2 terminated activity in S1 postsynaptic motor neurons and entrained the frequency of activity in S3 postsynaptic motor neurons. Hyperpolarization of neuron B2 disrupted the production of the standard motor pattern by eliminating S2 postsynaptic potentials in identified buccal motor neurons, thereby prolonging S1 activity and disrupting S3 bursting. 4. These data support the hypothesis that S2 neuron B2 is glutamatergic and demonstrate that glutamatergic transmission, and especially inhibition, is fundamental to the production of behaviorally critical motor neuron activity patterns in Helisoma.

The health status of women in Oaxaca: determinants and consequences.

Survey data from a sample of 575 women from the city of Oaxaca de Juárez, Mexico, are analyzed to ascertain the effect of the receipt of job-related benefits, including health benefits, on the self-reported health status of women, their rating of the health of the members of their household, and their satisfaction with the health of the members of their household. Health status depends on the woman's age, her socioeconomic status, and the number of children she has borne. Her rating of the health of the members of her household is related to her age, her socioeconomic status, and her rating of her own health. Satisfaction with the physical health of the members of the household is a function her health, her rating of the health of her household, her age, her socioeconomic status and the number of children she has borne. The overall conclusion is that, in this study, it is socioeconomic and demographic factors that are important in determining the woman's health status, rather than the receipt of job-related benefits. That she reports good health is an important factor in her view of her family's health and her satisfaction with her own health and that of her family.

Glutamate as a putative neurotransmitter in the buccal central pattern generator of Helisoma trivolvis.

1. The effects of L-glutamate superfusion over identified neurons within the buccal ganglia of Helisoma trivolvis were examined. Glutamate mirrored the effect of activity of subunit 2 (S2) of the tripartite feeding central pattern generator (CPG) on S2 postsynaptic neurons. Neurons that are excited by S2 are depolarized by glutamate, whereas neurons that are inhibited by S2 are hyperpolarized by glutamate. Glutamate also stimulated rhythmic S2 activity. 2. Different glutamate agonists could mimic specific components of the effects of glutamate on buccal neurons. Kainate produced depolarizations in neurons that receive S2 excitatory postsynaptic potentials (EPSPs) and activated rhythmic S2 activity. Quisqualate produced hyperpolarizations in neurons that receive S2 inhibitory postsynaptic potentials (IPSPs). 3. The non-N-methyl-D-aspartate glutamate receptor antagonist cyano-7-nitroquinoxaline-2,3-dione (CNQX) blocked the effects of S2 EPSPs and depolarizations produced by application of glutamate and kainate, but was ineffective in blocking S2 IPSPs or hyperpolarizations produced by application of glutamate and quisqualate. 4. These data support the hypothesis that glutamate is the transmitter of S2 of the feeding CPG in Helisoma, acting at CNQX-sensitive kainate-like receptors at excitatory synapses and CNQX-insensitive quisqualate-like receptors at inhibitory synapses.

Migrants to and in Oaxaca City.

"This paper examines migration to Oaxaca City, an intermediate city in southern Mexico, and describes the differences between migrants and non-migrants. The data show that migrants to Oaxaca City tend to come from district capitals rather than more rural municipios. Once in Oaxaca, migrants are not as different from non-migrants as is commonly asserted in the literature."

A method for in vitro mapping of ultrasonic speed and density in breast tissue.

A method has been developed for mapping density and ultrasonic speed in 1 mm thick slices of soft tissue with a resolution of about 1 mm. Tests using phantom sections have verified the accuracy and resolution of the ultrasonic speed maps. The method has been applied to breast tissues of three patients including tumors and surrounding tissue. Fixing a specimen in 5% formaldehyde did not change the degree of local variation in ultrasonic speeds, and raised mean speeds by less than 0.8%. The densities with fixing remained almost unchanged at low tissue densities (0.93 g/cm3), but rose 1.5% for higher tissue density (greater than 1.00 g/cm3).