Comparison of alveolar ventilation, oxygenation, pressure support, and respiratory system resistance in response to noninvasive versus conventional mechanical ventilation in foals

OBJECTIVE: To compare the efficacy of positive pressure ventilation applied through a mask versus an endotracheal tube, using anesthetized/paralyzed foals as a model for foals with hypoventilation. ANIMALS: Six 1-month-old foals. PROCEDURE: A crossover design was used to compare the physiologic response of foals to 2 ventilatory techniques, noninvasive mask mechanical ventilation (NIMV) versus endotracheal mechanical ventilation (ETMV), during a single period of anesthesia and paralysis. Arterial pH, PaO2, PaCO2, oxygen saturation, end-tidal CO2 tension, airway pressures, total respiratory system resistance, resistance across the upper airways (proximal to the midtracheal region), and positive end-expiratory pressures (PEEP) were measured. Only tidal volume (VT; 10, 12.5, and 15 ml/kg of body weight) or PEEP (7 cm of H2O) varied. RESULTS: Compared with ETMV, use of NIMV at equivalent VT resulted in PaCO2 and pH values that were significantly higher, but PaO2 was only slightly lower. Between the 2 methods, peak airway pressure was similar, but peak expiratory flow was significantly lower and total respiratory resistance higher at each VT for NIMV. Delivery of PEEP (7 cm of H2O) was slightly better for ETMV (7.1 +/- 1.3 cm of H2O) than for NIMV (5.6 +/- 0.6 cm of H2O). CONCLUSION: These data suggest that use of NIMV induces similar physiologic effects as ETMV, but the nasal cavities and mask contribute greater dead space, manifesting in hypercapnia. Increasing the VT used on a per kilogram of body weight basis, or the use of pressure-cycled ventilation might reduce hypercapnia during NIMV. CLINICAL RELEVANCE: Use of NIMV might be applicable in selected foals, such as those with hypoventilation and minimal changes in lung compliance, during weaning from endotracheal mechanical ventilation, or for short-term ventilation in weak foals.     

Immobilization of β‐amylase using polyacrylamide polymer derivatives

Barley β‐amlyase was immobilized on two polymeric materials; poly(acrylamide–acrylic acid) resin [P(AM‐AAc)] and poly(acrylamide–acrylic acid–diallylamine–HCl) resin [P(P(AM‐AAc‐DAA‐HCl) using two different methods: covalent and cross‐linking immobilization. Thionyl chloride, used to activate the polymers for covalent immobilization, has the advantage that it is able to react with a number of surface groups of protein under very mild conditions. Cross‐linking with glutaraldehyde gave a higher coupling yield (approximately 70%) than covalent immobilization (approximately 20%). The activity and stability of the resulting biopolymers have been compared with those of free β‐amylase. The specific activity of the immobilized enzyme was significantly influenced by the amount of enzyme loaded onto the polymers, the optimal level being 3.5 mg g^?1 polymer. It was found that the immobilized β‐amylase stored at 4°C retained approximately 90% of its original activity after 30 days, whereas free β‐amylase stored in solution at 4°C retained only 47% of its activity after same period. The difference in long term stability was more significant when the enzyme was stored at room temperature; the immobilized enzyme maintained 40% of its activity after 30 days, whereas the residual activity of free enzyme was only 10%. Copyright © 2003 Society of Chemical Industry     

Resting metabolic rate in subjects with paraplegia: the effect of pressure sores

OBJECTIVE: To determine the overall effect of paraplegia and pressure sores on resting metabolic rate. DESIGN: Unblinded, case-control study using a convenience sample. SETTING: Hospital primary care setting. PATIENTS: Fourteen individuals with paraplegia and pressure sores (PS-Para), 24 with paraplegia in good health (NPS-Para), and 23 non-spinal cord injury (SCI) controls. MAIN OUTCOME MEASURES: The planned outcome measures consisted of resting metabolic rate, percent of predicted resting metabolic rate, resting metabolic rate per kilogram body weight, and resting metabolic rate per meter squared body surface area. Post hoc analyses were used to identify the effect of completeness of lesion, smoking, and pressure sores on percent of predicted resting metabolic rate and resting metabolic rate per kilogram body weight. RESULTS: Percent of predicted resting metabolic rate and resting metabolic rate per kilogram body weight were significantly higher in the PS-Para group than in the NPS-Para or control groups (115% +/- 4% vs 100% +/- 2% or 107% +/- 2%, p < .05) and (25.9 +/- 1.2 vs 21.4 +/- 0.6 or 22.5 +/- 0.4 kcal/kg, p < .05, respectively). The resting metabolic rate per meter squared body surface area was significantly higher in the PS-Para group than in NPS-Para group (973 +/- 39 vs 874 +/- 20kcal/m2, p < .05). In the PS-Para group, current smokers had significantly higher resting metabolic rate per kilogram body weight than nonsmokers (27.3 +/- 1.7 vs 24.0 +/- 1.4kcal/kg, p < .01). Controlling for the effects of smoking in a multiple regression model, those in the PS-Para group had significantly (p < .001) greater percent of predicted resting metabolic rate and resting metabolic rate per kilogram body weight than those in the NPS-Para group. CONCLUSIONS: These findings indicate that individuals with SCI may have a decreased percent of predicted resting metabolic rate and those with pressure sores may have a hypermetabolic state. This hypermetabolic state is significantly higher than that resulting from smoking. Because ordinary prediction equations for energy expenditure may not be accurate when applied to subjects with paraplegia and pressure sores, quantification of energy needs by indirect calorimetry is recommended.     

Oral bioavailability of CHF1194, an inclusion complex of piroxicam and beta-cyclodextrin, in healthy subjects under single dose and steady-state conditions

CHF1194 is an inclusion complex of beta-cyclodextrin with the nonsteroidal anti-inflammatory drug piroxicam. In man, beta-cyclodextrin acts as a carrier of piroxicam. As the inclusion complex of piroxicam-beta-cyclodextrin is wettable and more water soluble, the absorption rate of the drug is increased whilst its other pharmacokinetic characteristics remain unchanged. The aim of the present study in 12 healthy subjects was to compare the oral bioavailability of 20 mg piroxicam in a CHF1194 tablet and a plain piroxicam capsule after a single dose and after two weeks of once daily administration, and also to assess the plasma levels and urinary excretion of beta-cyclodextrin after CHF1194 administration. The two treatments were administered in cross-over fashion, separated by a wash-out period of three weeks. Piroxicam, 5'-hydroxypiroxicam and beta-cyclodextrin were monitored in plasma and urine for 120 h after the first and last doses. Clinical tolerance was excellent and no adverse event occurred during either phase of the study. The extent of absorption of piroxicam from the CHF1194 tablet after the single dose was equivalent to that after the plain piroxicam capsule, within confidence limits of less than 80-125%. After repeated dosing, CHF1194 yielded the same steady-state systemic concentrations of piroxicam and 5'-hydroxypiroxicam as the reference capsule, and similar excretion pattern of the metabolite. After both single and multiple dosing, piroxicam was absorbed more rapidly after CHF1194, an expected consequence of the complexation of piroxicam with beta-cyclodextrin.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antidepressant treatment of pathologic laughing or crying in elderly stroke patients

Pathologic laughing or crying (PLC), a complication of many neurologic disorders, involves behavior that is either inappropriate to the context or to the patient's subjective feeling state. It is due to a dysregulation of the motoric components of emotional experience. PLC is distinct from, but often associated with, major depression. The relatively few reports on treatment of PLC are primarily with tricyclic antidepressants. We report the effective treatment of PLC due to stroke in three patients with nortriptyline or fluoxetine. The cases also illustrate the broad spectrum of depressive symptoms (from none to a major depression) seen in patients with PLC. We discuss treatment implications and directions for future research.     

Detecting psychiatric disorders in medical practice using the General Health Questionnaire. Why do cut-off scores vary?

In this study we assessed the accuracy of the General Health Questionnaire in detecting psychiatric disorders in general medical out-patients. A total of 290 newly referred patients were interviewed with the Present State Examination. Prior to the interview, 112 patients completed the full GHQ-60, 100 completed the GHQ-30 and 78 completed the GHQ-12. Data from the first group were used to study the full GHQ-60, together with the GHQ-30 and and GHQ-12, when disembedded from the full questionnaire. In a comparison between the disembedded and the separate versions of the GHQ-30 and GHQ-12 we observed considerable variation in the cut-off scores where a certain sensitivity and specificity was attained. In ROC-analysis, the versions were not materially different in their discriminatory capacity (area under the curve). The use of different criteria to define a 'case' demonstrated that case severity was another source of increasing cut-off scores. Our data demonstrate that the use of disembedded or separate versions of the questionnaire, together with variation in the case criteria can be a major explanation for variation in cut-off scores that was observed in previous studies.     

CONSISTENCY CHECKING ALONG TIME

Most model-based approaches to diagnosis require a consistency-checking procedure to perform their task. When dealing with a dynamically changing system, such a procedure must take into account time-varying data. This requires suitable techniques for reasoning over time. Additional difficulties arise when delays are involved in interactions between variables. The worst case occurs when some of the delays are completely unspecified. This report presents an approach to consistency checking that handles qualitative models of dynamic systems exhibiting time lags. A component-centered ontology is adopted to model the structure of the physical system, and an episode-based approach is adopted for representing its behavior over time. An example consisting of a physical process exhibiting transportation lags is used to illustrate the power of the approach. We present algorithms and an implementation in PROLOG called C-CAT (consistency checking along time). Some meaningful outputs from the program are used as examples. The solution proposed represents an extension to B. C. Williams' temporal constraint propagation methodology. It also extends the applicability range of existing approaches to model-based diagnosis, permitting its use in tasks such as online diagnosis of dynamic systems.     

The nucleus negatively controls the synthesis of mitochondrial proteins in the sea urchin egg

Enucleation of Paracentrotus lividus eggs, followed by parthenogenetic activation induces a sharp increase in the synthesis of mitochondrial proteins as shown by electrofluorography after in vivo labeling with radioactive amino acids. These results further substantiate the hypothesis that the cell nucleus negatively controls mitochondrial replication in the sea urchin egg.