Utility of a Low-Cost, Dense Sensor Network for the Study of Air Quality Impact Upon Human Health in Urban and Rural Areas.

The chemical composition of air changes from moment to moment. While the atmosphere may appear clear and cloudless to the human eye, gases, aerosols, and particulates are in constant interaction with Earth's surface under the influence of meteorological conditions. The recent emergence of low-cost, dense environmental air quality monitoring networks suggests growing interest in highly granular temporospatial exposure assessments by scientists and citizens. This chapter describes the utility of leveraging partnerships and resources to collocate a dense network of low-cost air quality sensors with meteorological sensors across a predominantly rural state located in the southeastern U.S. Construction of the network will improve knowledge on the daily, diurnal, and seasonal variations of pollutant exposures in rural and urban areas, the public health impact of extreme climatological and atmospheric events, and socioeconomic factors that heighten risk of exposures and health outcomes.

Effect of feeding three lysine to energy diets on growth, body composition and age at puberty in replacement gilts.

This study evaluated the effect of diets differing in standard ileal digestible (SID) lysine on lysine intake, growth rate, body composition and age at puberty on maternal line gilts. Crossbred Large White×Landrace gilts (n=641) were fed corn-soybean diets differing in SID lysine concentration (%, g SID lysine:Mcal ME); diets were not isocaloric. Gilts received three grower, finisher diet combinations: low (0.68% lysine grower, 0.52% lysine finisher), medium (0.79% lysine grower, 0.60% lysine finisher) or high (0.90% lysine grower, 0.68% lysine finisher). Grower diets were fed from 100 until 142days of age, and finisher diets were fed until they reached 220days of age. Body weight (BW), backfat thickness (BF), and loin depth (LD) were recorded every 28days. From 160-220days of age, gilts were exposed daily to vasectomized boars and observed for behavioral estrus. Gilts fed the low lysine diet had lower average daily gain and BW (P<0.05), but not fat depth:LD ratio. The percentage of gilts that displayed natural estrus by 220days of age was low but not different among dietary treatments (low 27.7%, medium 31.0% and high 37.7%, respectively; P=0.1201). Gilts fed the high and medium diets reached puberty 10 and 6days earlier, however, than gilts fed the low lysine diet (P<0.05). The rate of puberty attainment may have been less because all gilts contracted porcine epidemic diarrhea (PEDv) just as boar exposure was to begin for the first group of gilts. Results from the present study indicate that growth rate and age at puberty can be altered by ad libitum fed diets that differ in SID lysine concentration.

Efficacy of a supplemental candy coproduct as an alternative carbohydrate source to lactose on growth performance of newly weaned pigs in a commercial farm condition.

The experiment investigated the effects of a supplemental candy coproduct (Chocolate Candy Feed [CCF]; International Ingredient Corp., St. Louis, MO), an alternative carbohydrate source to dietary lactose, on growth performance and on health status of nursery pigs. Crossbred pigs ( = 1,408; 21 d of age and 7.1 ± 0.3 kg BW; Smithfield Premium Genetics, Rose Hill, NC) were randomly assigned to 4 treatments (16 pens/treatment and 22 pigs/pen) in a randomized complete block design: 0, 15, 30, and 45% of lactose replaced by CCF based on equal amounts of total sugars. The experimental period was divided into 3 phases: phase I (1.8 kg diet/pig for 11 ± 1 d), phase II (6.8 kg diet/pig for 17 ± 2 d), and phase III (until 49 d after weaning). Pigs received a common phase III diet. The levels of lactose, supplied by whey permeate (79.3 ± 0.8% lactose), were 20, 8, and 0% in phase I, II, and III, respectively. All experimental diets contained the same levels of essential AA and energy (ME) for each phase. Fecal scores were observed on d 5, 7, and 9 after weaning. Blood samples were taken at the end of phase I and II to measure blood urea N. The duration of phase I tended to linearly decrease ( = 0.063) with increasing CCF. In phase I, the ADFI increased ( < 0.05) with increasing CCF whereas ADG and G:F did not change. In phase II, the duration and ADFI did not change whereas ADG linearly decreased ( < 0.05) with increasing CCF. However, the G:F was not changed as CCF increased. During phase I and II together, the duration was linearly decreased ( < 0.05) as CCF increased, whereas no difference in growth performance was observed. Overall, ADFI, ADG, and G:F were not affected by replacing whey permeate with CCF in diets, indicating no adverse effects of a candy coproduct as a carbohydrate substitute to lactose on growth performance of nursery pigs. Blood urea N did not change in phase I but tended to linearly increase ( = 0.088) in phase II as CCF increased. There were no differences in fecal scores and mortality as CCF increased. However, increasing CCF tended to linearly decrease ( = 0.083) morbidity, which implies no adverse effects of a candy coproduct replacement on health status of nursery pigs. In conclusion, a candy coproduct can be used to replace up to 45% of dietary lactose for nursery pigs without negative effects on growth performance or health status. A candy coproduct could be an economical alternative to partly replace the use of lactose in swine production.

Optimal dietary energy and amino acids for gilt development: Growth, body composition, feed intake, and carcass composition traits.

The objective of this study was to determine if body composition of developing gilts could be altered at the onset of estrus by ad libitum feeding diets differing in standard ileal digestible (SID) lysine and ME using levels that are within those used in practice by pig producers in the United States. Crossbred Large White × Landrace gilts ( = 1,221), housed in groups, were randomly allotted to 6 corn-soybean diets in a 2 × 3 factorial arrangement formulated to provide 2 SID lysine and 3 ME levels. Gilts received grower diets formulated to provide 0.86 (low) or 1.02% (high) SID lysine and 2.94 (low), 3.25 (medium), or 3.57 (high) Mcal of ME/kg from 100 d of age until approximately 90 kg BW. Then, gilts were fed finisher diets containing 0.73 (low) or 0.85% (high) SID lysine and 2.94 (low), 3.26 (medium) or 3.59 (high) Mcal of ME/kg until 260 d of age. The medium SID lysine and medium-ME diets were based on an informal survey from the U.S. commercial swine industry to obtain average levels that are currently being formulated for developing gilts. Gilts were weighed and backfat thickness and loin area were recorded at the beginning of the trial and then every 28 d. Feed intake (FI) was recorded as feed disappearance within the pen at 2-wk intervals. Lysine (g) and ME (Mcal) consumed were calculated based on diet formulations. At approximately 260 d of age, gilts were slaughtered and warm carcass weight and fat thickness were recorded. There were no differences between lysine or ME levels for growth and body composition, except for backfat, which was slightly greater for gilts fed a high-ME diet. Gilts fed high-ME diets had a lower FI but a greater ME intake compared with gilts fed low ME ( < 0.05). Additionally, gilts fed the high-ME diet had lower FI and lysine intake per kilogram of BW gain when compared with gilts fed low- or medium-ME diets ( < 0.05). However, there was no difference in the megacalories consumed per kilogram of BW gain among treatments ( > 0.05). Carcasses from gilts fed the high-ME diet were 3.3 and 2.5 kg heavier than those from gilts fed the low- or medium-ME diets ( < 0.05). Despite significant differences in the lysine:ME ratio in the diets, no changes in growth or body composition occurred, likely due to compensatory changes in FI in response to dietary ME content. Caloric efficiency (Mcal to deposit 1 kg of BW) was similar among treatments.

Nutrient value of spray field forages fed to pigs and the use of feed enzymes to enhance nutrient digestibility.

This study determined the DE, ME, apparent total tract digestibility (ATTD) of N, and N retention of spray field forages (Bermuda grass, forage sorghum, and sweet sorghum) fed to pigs and the effects of the supplemental feed enzymes on energy and N utilization. A basal diet was formulated with 96% corn and 4% amino acids, minerals, and vitamins. Test diets contained 85% basal diet + 15% Bermuda grass, forage sorghum, or sweet sorghum. Allzyme SSF (Alltech, Nicholasville, KY) was used as a feed enzyme, which was composed of cellulase, glucanase, xylanase, phytase, and protease. The basal diet and test diets were evaluated by using 4 sets of 2 × 2 Latin square designs consisting of 2 pigs and 2 periods with a total of 32 barrows (38.7 ± 7.9 kg). Each period (10-d adjustment and 4-d collection) had 2 Latin squares. The 2 treatments were levels of enzyme supplementation (0 or 200 mg/kg). Pigs received experimental diets twice daily (0700 and 1700 h) at a fixed amount based on BW of pigs (0.09 × BW0.75 kg). On d 10, chromic oxide (0.5%) was added to the diets at 1700 h as an external marker. Fecal and urine samples were collected during 4 consecutive days. The basal diet contained 3,850 kcal DE/kg, 3,769 kcal ME/kg, 86.06% ATTD of N, and 71.10% N retention and was not affected by enzyme supplementation. Bermuda grass contained 893 kcal DE/kg, 845 kcal ME/kg, -16.50% ATTD of N, and -37.49% N retention and tended to be improved by enzyme supplementation to 1,211 kcal DE/kg (P = 0.098), 1,185 kcal ME/kg (P = 0.081), and -10.54% N retention (P = 0.076). The ATTD of N of Bermuda grass increased (P < 0.05) to 0.08% by enzyme supplementation. The forage sorghum contained 1,520 kcal DE/kg, 1,511 kcal ME/kg, -0.72% ATTD of N, and -16.99% N retention. The sweet sorghum contained 1,086 kcal DE/kg, 1,061 kcal ME/kg, -75.47% ATTD of N, and -49.22% N retention. Enzyme supplementation did not improve energy digestibility of forage sorghum and sweet sorghum. Nitrogen in these forages was poorly utilized. In conclusion, spray field forages including Bermuda grass, forage sorghum, and sweet sorghum can partly be utilized in pig feed to provide energy, although N is rather poorly digested. Feed enzymes could enhance both energy and N utilization in Bermuda grass but not sorghum.

Preweaning mortality in group-housed lactating sows: hormonal differences between high risk and low risk sows.

This study used an endocrinological approach to explain the differences between sows that have higher vs. lower preweaning mortality in a group-farrowing system. The association between sows that had 2 or more piglets die within the first 72 h postfarrowing (high risk) or sows that had 1 or no piglets die within the first 72 h postfarrowing (low risk) with changes in serum hormone concentrations was investigated. Multiparous sows (n = 63; parity 2 to 7) from 4 contemporary breeding groups, each mated within a week, were used. Sows were housed in a group-farrowing system where 8 sows farrowed in individual pens and shared a communal feeding and dunging area in each room. Reproductive performance, including total born, born alive, and stillborn per litter, individual weight of piglets at birth and weaning (at 5 wk postfarrowing), litter size at weaning, preweaning mortality of piglets, and sow BW before farrowing and after weaning, were recorded for all sows. Of these sows, 14 sows from 2 breeding groups were selected randomly for blood sampling through an indwelling ear vein catheter. A blood sample was collected daily from each sow 2 d prefarrowing through 2 d postfarrowing. Serum samples were analyzed for prolactin, oxytocin, cortisol, and urocortin concentrations using RIA. Among the 14 sows, 7 sows lost 2 or more piglets during the first 72 h after farrowing and were classified as high risk sows, and the other 7 sows lost 0 or 1 piglet during the same period and were classified as low risk sows. Catheters in 11 sows (5 high risk sows and 6 low risk sows) remained functional for the entire sampling period. Results indicate that high risk sows farrowed larger litters (live born = 13.8 ± 0.50 vs. 11.3 ± 0.48 piglets; P = 0.03) with lighter piglets (1.4 ± 0.04 vs. 1.7 ± 0.05 kg; P < 0.001) compared with low risk sows. In addition, high risk sows had greater oxytocin concentrations (0.09 vs. 0.07 ng/mL; SE = 0.02, P = 0.01), which might be associated with larger litters farrowed, compared with low risk sows. There were no differences between high risk and low risk sows (P > 0.30) in terms of serum prolactin, cortisol, or urocortin concentrations. These results suggest that litter size and birth weight of piglets played an important role in preweaning mortality of piglets and hormone concentrations in sows were not associated with piglet mortality in the group-farrowing system used.

Technical note: a technique for ear vein catheterization in group-housed sows.

No methods have been published for repeated blood sampling via an ear vein in group-housed sows. Therefore, the objective of this study was to develop a minimally invasive technique for the insertion of an ear vein catheter for repeated blood sampling in group-housed peripartum sows while minimizing any impact on production performance. Thirty-three multiparous pregnant sows were used including 18 catheterized sows and 15 control sows. In a group-farrowing barn, sows (8/room) shared a communal area and farrowed in individual, free-access pens. Treatment sows were anesthetized, and 1 ear was prepared aseptically 2 to 4 d before their expected farrowing date. A sterile needle was inserted into the largest and straightest portion of the vein, and the catheter, which was medical-grade microbore tubing, was inserted through the needle at least 24 cm. The needle was withdrawn, and the catheter was fixed into position and sutured to the ear. A blunt-end probe point cannula was glued onto the distal end of the catheter, and an adaptor injection cap with male Luer lock was placed on the end. The catheter was coiled and placed in a protective purse, which was cemented directly to the skin on the back of the shoulders. The catheter was flushed with heparinized saline to ensure patency. Once sows were able to stand, an elastic bandage was wrapped around the neck and upper body of the sow to hold the protective purse and exposed catheter in position. Blood samples were collected every 24 h, and catheters were flushed with heparinized saline after each collection. Fourteen of the 18 insertions were successful, and 11 of those remained functional for 4 d or more. Differences were not observed in reproductive performance between catheterized and noncatheterized sows.

Germ-line transformation of the Mexican fruit fly.

Germ-line transformation of a major agricultural pest, the Mexican fruit fly (Anastrepha ludens Loew, Mexfly), was achieved using composite piggyBac transposable elements marked with green, yellow and red fluorescent proteins (CopGreen, PhiYFP and J-Red). We also investigated the possibility of generating transposon-free insertions, in order to address potential concerns relating to proposed field use of transgenic Mexfly. We describe a highly efficient method for transforming Mexfly, compare efficiency of piggyBac terminal sequences for transformation and also describe the derivation of a transposon-free insertion line. The development of an efficient transformation system for Mexfly holds great promise for improved applications of the sterile insect technique, a major component of the present control measures for this economically important pest species.

Do patients get the best deal when antibiotics are prescribed out of hours?

OBJECTIVE: To investigate patients' compliance in obtaining follow on prescriptions after being prescribed a "starter pack" by the accident and emergency (A&E) department, and to assess the cost of the starter pack system. METHODS: During a study period of two months, out of hours prescriptions of antibiotic starter packs in A&E were monitored prospectively to determine how many patients returned to the hospital pharmacy or to their general practitioner (GP) for the remainder of the prescribed course. Current costs of out of hours antibiotic prescriptions were calculated, as were the costs of providing a full course of antibiotics on the patient's first visit to the A&E department. RESULTS: During the study period, 571 antibiotic items were prescribed as starter packs (three days' supply) to 437 patients. Of these, 232 (53%) chose to return to the hospital and 175 (40%) to their GP for the follow on prescription to complete their course. In 29 cases (7%) the information was not recorded and those patients were excluded from analysis. Only 50% of patients electing to obtain the follow on prescription from their GP did so compared with 83.7% of those electing to return to the hospital pharmacy. Failure to obtain the follow on prescription was termed "late primary non-compliance". There was an estimated annual saving to the hospital of Pounds 3131 if the patients were given the full course of antibiotics at their primary attendance at A&E. CONCLUSIONS: Patients prescribed antibiotics out of hours should be dispensed full courses. This would eliminate late primary non-compliance at no extra cost to the health authority.

Interrater reliability of hand-held dynamometry: effects of rater gender, body weight, and grip strength.

Clinicians and authors of previous publications have not reached agreement on the interrater reliability of dynametric strength testing. This study investigates the effects of gender, body weight, and grip strength on the reliability of hand-held dynametric strength measurements. Ten male and 10 female raters tested five muscle groups on the same two subjects (one male and one female) with a Chatillon Series D hand-held, spring-scale dynamometer. Both the raters and the test subjects were blinded to the dynametric output readings throughout the testing. Interrater reliability was good for all tests except for female raters when testing the male subjects' stronger muscle groups. Standard deviations were 61% and 50% greater for female vs. male raters for elbow flexors and knee extensors, respectively. Female raters' body weight had a significant correlation with torque when testing male subjects' wrist extensors, ankle dorsiflexors, and knee extensors (r > 0.64). Likewise, female raters' grip strength significantly correlated with torque when testing males' wrist extensors and elbow flexors (r >/= 0.71). The results indicate that gender, body weight, and grip strength affect a rater's ability to stabilize a hand-held dynamometer and could influence reliability when testing stronger muscle groups. J Orthop Sports Phys Ther 1992;16(2):74-81.

Carcinoma of the parathyroid gland: a 30-year experience.

Eleven patients with parathyroid carcinoma and 186 patients with parathyroid adenoma were seen between 1958 and 1990. Significant differences (p less than 0.01) were found between the two groups in calcium and parathormone levels, lesion size, presence of palpable mass, and severity of clinical presentation. Initial operative management consisted of parathyroidectomy alone in three patients, all of whom experienced recurrence of disease. Of the eight patients who underwent aggressive surgical management (parathyroidectomy and resection of thyroid or thymus), only one experienced recurrence. Three of the four patients with recurrence underwent multiple thoracic and cervical procedures for control of disease; one patient was treated with medical therapy alone. The mean survival in the surgical group was 17 years; the patient treated with medical therapy survived 10 years. In all four patients, however, treatment was palliative rather than curative. We conclude that patients with primary hyperparathyroidism characterized by markedly elevated serum calcium and parathormone, palpable mass, and severe clinical presentation should be suspected of harboring a parathyroid carcinoma. An aggressive initial surgical approach was considered in these patients. This experience emphasizes the importance of aggressive surgical extirpation in reducing disease recurrence and also for palliation and prolongation of life when recurrence does occur.

Cytochemical study of developing neurotransmitter properties of dissociated sympathetic neurons grown in co-culture with dissociated pineal cells.

We studied the development of neurotransmitter phenotype in sympathetic neurons grown in the presence of pinealocytes, a target tissue having adrenergic but not cholinergic receptors. Neurons, dissociated from neonatal rat superior cervical ganglia, were grown in co-culture with dissociated pineal cells. Both ganglionic and pineal non-neuronal background cells were allowed to grow nearly to confluency. Electron microscopic cytochemical techniques were used to examine sets of co-cultures at weekly intervals over 5 weeks. Adrenergic vesicles were identified by their dense granular precipitate following potassium permanganate fixation. We found that the percentage of small granular vesicles, both in synaptic boutons onto other neurons and in axonal varicosities, declined very little over 5 weeks. After an initial drop from 75 to 65%, the percentage of small granular vesicles remained remarkably constant. Throughout the 5 weeks, more than 70% of the boutons and varicosities contained a predominance of small granular vesicles; fewer than 20% contained a predominance of clear vesicles. Although both somal synaptic boutons and axonal varicosities retained a predominantly adrenergic ultrastructure, at certain weeks there was a statistically significant shift in the percent distribution of adrenergic vesicles in somal boutons compared with the distribution in axonal varicosities. Because these cultures were grown under conditions known to favor an induction of acetylcholine metabolism and a suppression of catecholamine metabolism, we conclude that the maintenance of adrenergic ultrastructure over 5 weeks may be due to the presence of the pineal cells.

Topography of rat liver microsomal 3-hydroxy-3-methylglutaryl coenzyme A reductase.

The orientation of 3-hydroxy-3-methylglutaryl coenzyme A reductase within the endoplasmic reticulum was investigated. Microsomal reductase activity was not latent, as addition of various detergents failed to activate the enzyme. Reductase activity was readily inhibited in intact microsomes by impermeable inhibitors such as trypsin, mercury dextran and anti-reductase IgG. Under the conditions used, these agents did not affect the intactness of microsomes as determined by latency of mannose-6-phosphate phosphohydrolase activity. The sensitivity to these inhibitors was not increased in disrupted microsomes. It is concluded that the domain containing the active site of the reductase is situated on the cytosolic surface of the endoplasmic reticulum.

The effects of salines and fixatives upon the size of an identified neuron.

Because accurate neuronal dimensions are essential for mathematical modeling of neuronal properties, the effects of a number of salines and fixative procedures on neuronal size were compared, including the non-chemical, freeze substitution method. Using an identified neuron we compared diameters and found some of the fixative-saline combinations caused shrinkage by as much as a factor of four from our best estimates of the in vivo size from the quick frozen preparations. A glutaraldehyde based fixation procedure was found which gives results in good agreement with the frozen tissue.

Multi-site phosphorylation in ox-kidney branched-chain 2-oxoacid dehydrogenase complex.

Tryptic [32P]phosphopeptides were prepared from [32P]phosphorylated ox-kidney branched-chain complex and analysed by high-voltage paper electrophoresis at pH 1.9. In the maximally phosphorylated complex 3 tryptic [32P]phosphopeptides were identified (TA, TB, TC). RF-values relative to N6-dinitrophenyllysine were (mean +/- SEM for 25 obs.): TA, 1.53 +/- 0.03; TB, 1.07 +/- 0.02; TC, 0.65 +/- 0.01. Relative rates of phosphorylation were TA greater than TB greater than TC. Phosphorylation of TA reached a maximum when about 66% of the complex was inactivated. Phosphorylation of TB and TC was associated mainly with 66-95% inactivation of the complex.

Ultrastructure of the water-movement-sensitive sensilla in the medicinal leech.

Behavioral and physiological experiments have shown that medicinal leeches are able to detect low amplitude surface waves, and further, that the transduction of this stimulus modality occurs primarily, if not exclusively, at the annular sensilla (Young, Dedwylder, and Friesen, 1981; Friesen, 1981). Here we examine the morphology of these specialized sensory structures using light, scanning electron, and transmission electron microscopes. We found that three types of ciliated sensory cells occur at the sensilla: (1) a uniciliate cell, with an axial cilium that projects at least 12 micrometers beyond the cuticle; (2) a multiciliate cell with from two to four grouped cilia that extend 1--3 micrometers beyond the cuticle; and (3) a second multiciliate cell, whose cilia project parallel to the body surface but remain within the cuticle. The cilia of all three cell types arise from the cuplike depressions which form the apices of slender, elongated cells (approximately 2 micrometers diameter X 50 micrometers length). A complexly interconnected ring of microvilli surrounds the cilium of the uniciliate cells. The morphology of the uniciliate cells closely resembles the structure of vibration-sensitive sensory neurons found in other species. We propose, based on previous results and our new findings, that the uniciliate receptor cells are the sensillar movement receptors which mediate leech sensitivity to water movements.

A comparative study by serial electron microscopy of neuromuscular junctions in the dimorphic claws of the snapping shrimp, Alpheus heterochelis.

We compared the neuromuscular junctions on the main closer muscle in the first pair of chelipeds in the snapping shrimp Alpheus heterochelis by serial section electron microscopy. We sought an ultrastructural basis for the different behavioral and physiological functions of these dimorphic claws and for the role of the nervous system in claw transformation. We were unable to detect any statistically significant morphological differences between the junctions. Further, we found the muscle fiber populations and filament arrangements, as well as the electrical properties of the fibers, to be more homogeneous and similar to each other in A. heterochelis than those reported for another species, A. armillatus. We consider our results in light of recent data on the anatomy and electrical properties of the motor neurons within the CNS and conclude that the neural trigger for claw transformation involves factors not revealed by conventional electron microscopy.

Structural comparison of a homologous neuron in gryllid and acridid insects.

The fast extensor tibiae (FETi) motor neuron is responsible for exciting the extensor tibiae muscle to produce most of the force for jumping in acridids. Because of its relatively large size and crucial role in jumping, FETi has been studied in an ever-increasing number of orthopteran species. Here we describe the structure of the metathoracic FETi neuron in six species of acridids and in two species of gryllids. The morphology of FETi within the respective groups is essentially equivalent, but marked differences are apparent between acridid and gryllid FETis. There are similarities in the size and location of the cell body and the course of the neurite through the ganglion. Differences are found in the number of large branches, density of branching, and the volume of neuropil receiving branches. We propose that the gryllid FETi is an intermediate form between slow extensor tibiae motor neurons involved in walking and acridid fast extensor tibiae motor neurons specialized for jumping.

Locust local nonspiking interneurons which tonically drive antagonistic motor neurons: physiology, morphology, and ultrastructure.

Local nonspiking interneurons have been implicated in the control of behavior. We have characterized the physiology of two local nonspiking interneurons in the locust and subsequently examined the neurons in the light and electron microscopes. Physiologically the two interneurons have opposite effects upon antagonistic motor neurons and are tonically releasing transmitter at their "resting potentials." This combination of tonic release and reciprocal driving of antagonistic motor neurons by single interneurons provides a hitherto undescribed means of controlling posture. One interneuron (DCVII, 4) excites flexor tibiae and inhibits the slow extensor tibiae motor neurons when depolarized. The other interneuron (DCVII, 5) inhibits the flexor tibiae and excites the slow extensor tibiae motor neurons when depolarized. In both cases, when the interneurons are hyperpolarized, they have the opposite effects upon the same motor neurons. Intracellular staining of these neurons confirms that they are local interneurons. Furthermore, an examination of sectioned material shows that the neurons are unique and can be identified as such in a population of locust neurons. Ultrastructurally, we find synapses only on the smaller (less than 2 micrometers) branches. These neurons may form the presynaptic element in either of two configurations, these being the discrete density (one presynaptic) and the dense bar (one presynaptic, two postsynaptic) type of configurations. The functional implications of these findings for neurons controlling posture are discussed.