Toward the development of a neural interface for lower limb prosthesis control.

Lower limb amputees form a large portion of the amputee population; however, current lower limb prostheses do not meet the needs of patients with high-level amputations who need to perform multi-joint coordinated movements. A critical missing element is an intuitive neural interface from which user intent can be determined. Surface EMG has been used as control source for upper limb prostheses for many years; for lower limb activities, however, the EMG is non-stationary and a new control strategy is required. This paper describes the work completed to date in developing a novel lower limb neural interface.

A real-time pattern recognition based myoelectric control usability study implemented in a virtual environment.

Pattern recognition based myoelectric control systems have been well researched; however very few systems have been implemented in a clinical environment. Although classification accuracy or classification error is the metric most often reported to describe how well these control systems perform, very little work research has been conducted to relate this measure to the usability of the system. This work presents a virtual clothespin usability test to assess the performance of pattern recognition based myoelectric control systems. The results suggest that users can complete the virtual task in reasonable time frames when using systems with high classification accuracies. Additionally, results indicate that a clinically-supported classifier training approach (inclusion of the transient potion of contraction signals) may reduce classification accuracy but increase real-time performance.

Plasma concentration of ionized calcium in healthy iguanas.

OBJECTIVE: To measure plasma concentration of ionized calcium in healthy green iguanas. DESIGN: Prospective study. ANIMALS: 9 juvenile and 21 (10 male, 11 female) adult iguanas. PROCEDURE: Blood samples were obtained from each iguana, and plasma calcium, glucose, phosphorus, uric acid, total protein, albumin, globulin, potassium, and ionized calcium concentrations, aspartate transaminase (AST) activity, and pH were measured. Heparinized blood was used for measurement of ionized calcium concentration and blood pH. A CBC was also performed to assess the health of the iguanas. RESULTS: Significant differences were not detected among the 3 groups (juveniles, males, and females) with regard to ionized calcium concentration. Mean ionized calcium concentration measured in blood was 1.47 +/- 0.105 mmol/L. Significant differences were detected between juveniles and adults for values of phosphorus, glucose, total protein, albumin, globulin, and AST activity. CONCLUSIONS AND CLINICAL RELEVANCE: Ionized calcium concentration provides a clinical measurement of the physiologically active calcium in circulation. Evaluation of physiologically active calcium in animals with suspected calcium imbalance that have total plasma calcium concentrations within reference range or in gravid animals with considerably increased total plasma calcium concentrations is vital for determining a therapeutic plan. Accurate evaluation of calcium status will provide assistance in the diagnosis of renal disease and seizures and allow for better evaluation of the health status of gravid female iguanas.

Morphologic and cytochemical characteristics of blood cells and hematologic and plasma biochemical reference ranges in green iguanas.

OBJECTIVE: To determine blood cell morphologic characteristics and hematologic and plasma biochemical reference ranges for iguanas housed in a warm indoor and outdoor environment with regular exposure to direct sunlight. DESIGN: Original study. ANIMALS: 51 clinically normal iguanas (18 males, 25 females, and 8 juveniles) housed in 3 Florida locations. PROCEDURE: Blood was collected from the coccygeal or ventral abdominal vein. Any samples that had obvious hemolysis or clot formation were not used. Leukocyte counts were determined manually; other hematologic values were obtained by use of a commercially available cell counter. Plasma biochemical values were determined by use of a spectrophotometric chemistry analyzer. Blood smears were stained with Wright-Giemsa and cytochemical stains for morphologic and cytochemical evaluation. RESULTS: Hematologic ranges were generally higher in this study than previously reported. Thrombocytes were variable in appearance between individuals and sometimes difficult to distinguish from lymphocytes on a Wright-Giemsa preparation. Concentrations of calcium, phosphorus, total protein, globulins, and cholesterol were significantly higher, and the albumin:globulin ratio was significantly lower, in healthy gravid females than in male or nongravid female iguanas. Nongravid females had significantly higher calcium and cholesterol concentrations, compared with males. The calcium:phosphorus ratio was > 1 in all iguanas. Gravid females had a calcium phosphorus product ranging between 210 and 800. Intracytoplasmic inclusions were identified within the erythrocytes of some iguanas. CONCLUSIONS AND CLINICAL RELEVANCE: Hematologic ranges for iguanas in this study are higher than those reported for iguanas. Sex and age of the iguana should be considered when evaluating biochemical values. Healthy ovulating and gravid females may have significantly increased electrolyte and protein concentrations, but maintain a calcium:phosphorus ratio > 1.

Partial characterization of retroviruses from boid snakes with inclusion body disease.

OBJECTIVE: To characterize retroviruses isolated from boid snakes with inclusion body disease (IBD). ANIMALS: 2 boa constrictors with IBD and 1 boa exposed to an affected snake. PROCEDURE: Snakes were euthanatized, and tissue specimens and blood samples were submitted for virus isolation. Tissue specimens were cultured with or without commercially available viper heart cells and examined by use of transmission electron microscopy (TEM) for evidence of viral replication. Reverse transcriptase activ ty was determined in sucrose gradient-purified virus. Western blotting was performed, using polyclonal antibodies against 1 of the isolated viruses. Specificity of the rabbit anti-virus antibody was evaluated, using an immunogold-labeling TEM technique. RESULTS: 3 viruses (RV-1, RV-2, and RV-3) were isolated. The isolates were morphologically comparable to members of the Retroviridae family. Reverse transcriptase activity was high in sucrose gradient fractions that were rich in virus. Polyclonal antibody against RV-1 reacted with proteins of similar relative mobility in RV-1 and RV-2. By use of immunogold labeling, this antibody also recognized virions of both RV-1 and RV-2. CONCLUSIONS AND CLINICAL RELEVANCE: A retrovirus was isolated from boid snakes with IBD or exposed to IBD. Western blot analysis of viral proteins indicated that viruses isolated from the different snakes were similar. Whether this virus represents the causative agent of IBD is yet to be determined. The isolation of retroviruses from boid snakes with IBD is an important step n the process of identifying the causative agent of this disease.

Nonreproductive surgery in reptiles.

As reptiles have gained popularity as pets, veterinarians are more frequently called on to perform surgical procedures on these pets. Veterinarians must have a basic understanding of the anatomic and physiologic differences between reptilian and mammalian companion animals. This article reviews some basic points about reptilian anatomy and physiology that are important to consider when performing surgery on reptilian patients. This article covers approaches to the coelomic cavity in the different groups of reptiles and some basic concepts regarding surgery on different, nonreproductive systems in these reptiles.

Reproductive surgery in reptiles.

Reptiles are commonly presented to veterinarians for reproductive problems. Often, these problems require surgical intervention. This article discusses some of the major causes of dystocia in reptiles and describes the surgical treatment of the female reproductive tract, including ovariectomy, ovariosalpingohysterectomy, and prolapse of the shell gland. Descriptions of surgical intervention in male reptiles include orchidectomy and paraphimosis.

Spontaneous cervical epidural haematoma.

Spontaneous spinal epidural haematoma can occur in the elderly and is a reversible cause of neurological deficit if treated promptly. The diagnosis can be made from a careful history and a simple neurological examination, but it can be confused with myocardial infarct, musculoskeletal pain, vasculitis and acute dissection of an aortic aneurysm. For a favourable outcome, early decompressive laminectomy and evacuation of the haematoma are necessary. We report an unusual case of acute quadriplegia in which prompt diagnosis and early intervention led to almost complete functional recovery with minimal disability.

Intraaortic spring coil loops: early and late results.

OBJECTIVES: Our aim was to determine the late fate of intraaortic spring coil loops after embolization of aortopulmonary vessels. BACKGROUND: In some aortopulmonary collateral vessels and patent ductus arteriosi, the narrowest segment is close to the aorta; coils used to close such vessels will "straddle" the lesion, allowing one or more coil loops to protrude into the aortic lumen. The consequences of this procedure are unknown. METHODS: We reviewed the cineangiograms of all patients who had at least one aortopulmonary collateral vessel or patent ductus arteriosus closure between January 1, 1988 and August 31, 1993. From this group, 53 patients had multiple-plane angiographic evidence of intraaortic coil loops. All subsequent cineangiograms were reviewed to determine coil position or movement and evidence of recanalization or endothelial coverage of the coil loop. We also reviewed each hospital record or communicated directly with referring physicians to identify any subsequent complications such as emboli or endocarditis. RESULTS: Of the 53 patients with intraaortic coil loops, 49 patients had closure of one or more aortopulmonary collateral vessels (59 vessels), and 4 had closure of a patient ductus arteriosus (4 vessels). Patient follow-up ranged from 1 day to 66 months (median 20 months); follow-up was not available in 6 patients. Five of the 53 patients (9.3%; 95% confidence limits [CL] 3.1% to 20.7%) died at operation or of end-stage heart failure. Patients with late angiography had no residual flow in 31 of 35 aortopulmonary collateral vessels (88.6%; 95% CL 73.3% to 96.8%), and 0.5 mm separated the coil and aortic contrast column in all 12 coils with adequate angiography, suggesting endothelial coverage of the intraaortic coil loop. No episodes of stroke, embolic events, endocarditis or coil migration were reported. CONCLUSIONS: Although coil occlusion of aortopulmonary collateral vessels or patent ductus arteriosi may produce intraaortic coil loops, endothelialization appears routine. No late complications associated with intraaortic coil loops were observed.

Can village mothers prepare oral rehydration solution?

PIP: Both the prepackaged glucose-electrolyte powder and the domestic rehydration solution have received wide publicity, yet there has been little evaluation of how accurate the mother can be in preparing the mixture. The 2 studies described here attempted to measure this human factor in actual field situations in India and Trinidad. The 1st study attempted to quantify the variability in the size of the 2-finger and thumb pinch of salt. The 2nd study measured the different concentrations when mothers diluted a standard packet of glucose and electrolytes in domestic vessels. In India and Trinidad, mothers of children with diarrhea were instructed about making up local salt-sugar-water mixtures for home treatment. They were shown how to take a 2-finger and thumb pinch of salt in a way which had previously been agreed upon. Multiple pinches--5 in Trinidad and 10 in India--were then weighed on standard laboratory scales to find the average salt picked up. The fingers of the mothers were measured to see if the weight of salt picked up correlated with hand size. Other factors which could influence the pinch size were also considered: type and quality of salt available and the relative humidity. In the packet dilution study, mothers in rural India were instructed in the local language by an indigenous nurse who used diagrams in the teaching. The glucose concentrations of the mixture made up by 66 village mothers were analyzed in the field by a pocket refractometer. The finger-pinch method of measuring salt was very inaccurate in field tests. At least 1 mother in 20 would pick up double the amount of salt intended. There was no statistical correlation between finger size and the weight of a pinch of salt. In the packet dilution study there was a wide range of concentrations, but over 83% of the mothers mixed the solution to within 40 mmol/liter of the "correct" value.^ieng