A voxel-by-voxel multivariate analysis of cerebral perfusion defects in divers with ''bends''

Past analysis of dysbaric-induced cerebral perfusion defects, demonstrated by 99Tcm-hexamethylpropylene amine oxime (99Tcm-HMPAO) single photon emission tomography in divers using quantitative and/or univariate techniques, has resulted i considerable controversy regarding the significance of these lesions compared to those seen in control subjects, correlations with clinical findings and the role of 99Tcm-HMPAO as a prognostic indicator in decompression sickness. We tried to address these problems by using a multivariate approach to a voxel-by-voxel analysis, involving the use of principal components, to determine ranges of normality in 50 reference controls. In subsequent images, abnormality was defined as 10 spatially connected voxels at an appropriate significance level of three standard deviations. The images of 50 divers with clinically diagnosed 'bends' were compared with those of a further 40 normal population controls with no previous history of loss of consciousness, head injury or dysbarism. The results showed that 19 of 50 divers with 'bends' and 3 of 40 population controls had significant perfusion defects, representing a significant difference between divers with dysbarism and population controls at the level P < 0.002. It is concluded that dysbarism causes significant cerebral cortical perfusion defects in affected divers both in 'silent' and symptomatic (clinically correlated) areas.     

Movement by helicopter of patients with decompression sickness

Rapid movement of a patient with decompression sickness sometimes poses problems when the site of the hyperbaric treatment facility is located a considerable distance away. Six cases of aviator decompression sickness were diagnosed in altitude chamber participants during an 18-month period. Five cases were uncomplicated decompression sickness and the sixth case was of central nervous system decompression sickness. All cases were transferred by low-level helicopter flight. No complications were noted when the helicopter stayed within 200 ft (61 m) AGL of the take-off point. Symptoms of decompression sickness did worsen however, when this altitude was exceeded. This study shows that movement of patients with decompression sickness by low-level helicopter flight is both safe and effective, especially when pressurized aircraft is neither available nor practical.     

How to control the blood glucose level in the surgical diabetic patient

Plasma activities of lactic dehydrogenase (LDH), creatine phosphokinase (CPK), glutamic pyruvic transaminase (GPT), and alkaline phosphatase (ALP) were studied, along with hematological changes, in rats suffering from various degrees of experimental decompression sickness (DS). By 1 h after decompression, LDH and CPK activities were elevated in moderate and severe DS whereas GOT and GPT were elevated only in severe DS. ALP was reduced in all decompressed rats. Hematological changes indicated hemoconcentration, the degree of which paralleled the severity of DS. By 24 h after decompression, all enzyme activities were approaching control levels with the exception of GOT, which was further elevated from the 1-h value. The observed lung damage in rats with severe DS in conjunction with the hematologic and enzyme data suggested that hypoxemic-hypoxia, incident to bubble embolization of pulmonary vasculature, was a major factor in altering the blood enzyme pattern in DS. Serum enzyme data from two inadequately decompressed divers are also reported.     

Incidence of decompression sickness in Navy low-pressure chambers

This study reports the incidence of decompression sickness occurring in U. S. Navy altitude chambers in association with physiological training of aircrews for the period 1 Jan. 1972 to 31 Dec. 1975. There were 79 cases of decompression sickness in 88,520 altitude chamber exposures, an incidence of 0.089%. Among trainees, there were 22 cases in 73,561 exposures, an incidence of 0.029%. Among chamber inside observers, there were 57 cases in 14,959 exposures, an incidence of 0.38%. This 12-fold greater incidence among inside observers over trainees was statistically significant (p less than 0.01). Reasons for the increased incidence of decompression sickness among inside observers are discussed.     

Recovery of nerve conduction following microvascular decompression for trigeminal neuralgia

OBJECTIVE: To assess the function of trigeminal nerve before and after microvascular decompression for trigeminal neuralgia. BACKGROUND: To date there is no direct evidence that microvascular decompression of the trigeminal root restores normal conduction in the nerve. METHODS: The authors examined 10 patients with trigeminal neuralgia in whom preoperative MRI and MR angiography demonstrated neurovascular contact. During microvascular decompression, the trigeminal nerve was monitored by recording early scalp trigeminal evoked potentials immediately before, during, and after decompression. Direct recordings from the root entry zone were also performed. RESULTS: In all patients preoperative scalp evoked potentials showed impaired conduction of the trigeminal root. Microvascular decompression was associated with immediate recovery of conduction in seven patients, demonstrated by both scalp evoked potentials and direct root recordings. All 10 patients were pain free postoperatively. CONCLUSIONS: Improvement in trigeminal neuralgia following microvascular decompression is often associated with normalization of neurophysiologic data, suggesting recovery of nerve function. Rapid electrophysiologic recovery and pain relief following microvascular decompression argue that neither phenomenon is linked to remyelination. It is possible that the trigeminal evoked potentials might predict an effective microvascular decompression.     

Can endothelial function be assessed in vivo by measuring acetylcholine induced changes in nitrate in the forearm in man?

A 26-yr-old AC-130 gunner developed unilateral temporomandibular joint (TMJ) pain while flying a combat support mission. A diagnosis of decompression sickness (DCS) was made based on his symptoms and risk factors that included prolonged exposure to high altitude (60 to 90 min at 18,000 ft), cold temperature (-11 degrees C), and increased inflight activity. His symptoms resolved with 100% oxygen and he was returned to flying status after 72 h. Altitude related DCS is an unusual occurrence and this is the first reported case of inflight DCS affecting the temporomandibular joint.     

Inner ear decompression sickness

With recent increases in commercial, military, and sport diving to deeper depths, inner ear injuries during such exposures have been encountered more frequently and noted during several phases of diving: during compression, at stable deep depths, with excessive noise exposure in diving, and during decompression. The pathophysiology of these injuries differs, depending upon the phase of diving in which the injuries occur. In this report, 23 cases of hearing loss, tinnitus, and/or vertigo occurring during or shortly after decompression are presented. Thirteen of these cases occurred in helium-oxygen dives involving a change to air during the latter stages of decompression. A significant correlation is present between prompt recompression treatment, relief of symptoms, and lack of residual deficits. Current knowledge indicates that the management of otologic decompression sickness should include: 1. prompt recompression to at least 99 feet deeper than the symptom onset depth; 2. recompression using the previous helium-oxygen mixture when the injuries occur during or shortly after a switch from helium-oxygen to air during the latter stages of decompression; 3. the use of parenteral diazepam for symptom relief and cyclic inhalations of oxygen enriched treatment gases; and 4. the avoidance of further diving by divers who exhibit permanent inner ear injuries after the acute symptoms have subsided.     

Injectable agent for the treatment of air emboli-induced paraplegia in rats

Rats with air emboli-induced paraplegia were treated with dialy levodopa injections (intra-arterially or intraperitoneally). Of the control animals, 20% fully recovered from paraplegia during a period of 7 d. Of the levodopa treated animals, 85% fully recovered during the same period. It appears, therefore, that levodopa might be one of the few injectable agents enhancing recovery from air-induced paraplegia, suggesting its possible use in decompression sickness.     

Decompression sickness in Ireland--a review

In the last decade there has been an increase in the incidence of decompression sickness in Ireland. The modern diver, equipped with specially developed diving equipment, is exposed to abnormal physiological conditions. This has resulted in a spectrum of medical conditions, which need to be recognised, diagnosed and treated. The department of Underwater Medicine at University College Hospital, Galway, is the only referral centre in the Republic of Ireland for patients suffering from decompression sickness. Early recognition and referral for treatment dramatically improves patient outcome. A one year's review of patients referred for treatment is presented.     

Late hematologic status after chemotherapy observed in patients 3 to 10 years after treatment

The aim of the present study is the evaluation of late hematological complication in patients who received aggressive chemotherapy, and were observed 3, 5 and 10 years after treatment was completed. In the group of 35 patients, besides high percent of early hematological complications, there was only one case of anemia grade 2 (acc. to WHO score). We concluded that the hematological recovery after aggressive chemotherapy was satisfactory. No secondary hematological malignancies have been found.     

Role of spinal gamma-aminobutyric acidA receptors in formalin-induced nociception in the rat

This study investigated the role of gamma-aminobutyric acid (GABA) and GABA(A) receptors in the spinal cord in the expression of pain behaviors evoked by injection of formalin in concentrations ranging from 0.25 to 2.5% in the hindpaw of the rat. Two approaches were used. The first approach compared the effect of drug treatment to saline at each concentration of formalin. The second approach examined the effect of drug treatment on the concentration-response functions of formalin, i.e., its EC50. Intrathecal (i.t.) pretreatment with 0.03 to 0.3 microg of bicuculline, a GABA(A) receptor antagonist, dose-dependently increased the number of flinches and weighted pain scores in the interphase and phase 2, but did not alter responses in phase 1. In the interphase, the EC50 values of formalin for number of flinches or weighted pain score in bicuculline-pretreated rats were decreased to one-third or one-fourth, respectively, of their values in saline-pretreated rats. In phase 2, the EC50 values of formalin for number of flinches or weighted pain score in bicuculline-pretreated rats were similarly decreased to one-half of their value in saline-pretreated rats. These results suggest that formalin was a significantly more noxious stimulus in the presence of bicuculline. Pretreatment with the GABA(A) receptor agonists, muscimol (0.3 microg) or isoguvacine (10 or 30 microg i.t.), significantly decreased the number of flinches in phase 1 and phase 2, but produced only a marginal decrease in the weighted pain score at the highest doses. These findings suggest that there is little tonic activation of GABA(A) receptors by GABA in the spinal cord before or immediately after the injection of formalin. However, approximately 10 min after the induction of injury by formalin, there is a release of GABA and activation of GABA(A) receptors in the spinal cord that 1) contributes to the period of quiescence between phase 1 and phase 2 and 2) coincidentally diminishes the magnitude of pain behaviors in phase 2, possibly by limiting the development of central sensitization in the spinal cord.     

The effect of tourniquet release time on the analgesic efficacy of intraarticular morphine after arthroscopic knee surgery

A randomized, controlled study was conducted in patients undergoing elective arthroscopic knee surgery to assess the effects of tourniquet release time on analgesia after intraarticular (I.A.) injection of morphine. Standardized general anesthetic and surgical techniques were used for all patients, including a thigh tourniquet inflated at pressures between 300 and 350 mm Hg. At the conclusion of the arthroscopic procedure, 5 mg morphine in 25 mL saline was administered I.A. Patients were then randomized to one of two treatment groups. In Group 1 (n = 20), the tourniquet was kept inflated for 10 min after I.A. injection, whereas in Group 2 (n = 20), the tourniquet was deflated immediately after I.A. injection. Postoperative pain was assessed using a visual analog scale in the recovery room when the patients were awake and at 2, 4, 6, 8, and 24 h after I.A. injection. Patients who complained of pain in the recovery room received increments of intravenous meperidine 25-50 mg. On discharge from the recovery room, patients received oral mefenamic acid 250-500 mg for pain relief. The time and quantity of analgesics required were recorded. Patients in Group 1 had significantly (P < 0.05) lower pain scores than those in Group 2 at 2, 4, 6, and 8 h postoperatively. These low pain scores were associated with lower requirements of supplementary analgesics. We conclude that, as compared with releasing the tourniquet immediately after I.A. injection of morphine, maintaining the tourniquet inflated for 10 min provides superior analgesia and decreases the need for supplemental analgesics.     

Dysbaric osteonecrosis in divers and caisson workers. An animal model

Dysbaric osteonecrosis was induced successfully in adult sheep after 12 to 13, 24-hour exposures to compressed air (2.6-2.9 atmospheres absolute) during a 2-month period. All exposed sheep had decompression sickness and extensive bone and marrow necrosis in their long bones. Radiographic analysis of these progressive lesions showed mottled to distinct medullary opacities and endosteal thickening characteristic of dysbaric osteonecrosis. Six months after the last hyperbaric exposure, neovascularization of once ischemic fatty marrow was centripetal from the diaphyseal cortex. Proliferating endosteal new bone, fatty marrow calcification, and appositional new bone formation were widespread. Juxtaarticular osteonecrosis involved marrow fibrosis and loss of osteocytes in subchondral cortical bone. Tidemark reduplication in juxtaarticular bone and cartilage thinning suggested possible early osteoarthritis induction by recurrent episodes of transient ischemia after multiple hyperbaric exposures. Dysbaric osteonecrosis appears to involve a bone compartment syndrome of elevated intramedullary pressure initiated by decompression induced N2 bubble formation in the fatty marrow of the long bones. An animal model that can be used to investigate the pathogenesis, diagnosis, and treatment of dysbaric osteonecrosis is discussed.     

Pressure-reduction limits for rats following steady-state exposures between 6 and 60 ATA

The role of pressure reduction in the formation and growth of bubbles is universally recognized and its significance in decompression theory has been accepted. Yet the allowable limits of pressure reduction for man and animal are uncertain. This study sought to evaluate the pressure-reduction limits for rats following steady-state exposures at pressures greater than 1 atm. To define the relationship, 350 albino rats were exposed to 1 of 12 specified pressure levels between 6 and 60 ATA and then abruptly decompressed to a preselected reduced pressure level for observation. The pressure-reduction levels were selected to determine for each saturation-exposure level an ED-50 (i.e. the effective dose that will produce decompression sickness in 50% of the animals). The results demonstrate three consistent findings: (1) there is a linear relationship (r = .99) between the magnitude of a safe pressure reduction and the saturation exposures between 6 and 43 ATA; (2) at pressures greater than 43 ATA, there is a qualitative change in the decompression sickness symptoms and a reduction in the precision of the mathematical relationship (r = .44); and (3) the magnitude of the pressure change required to increase the incidence of decompression sickness from 10% to 90% is directly related to the magnitude of the exposure pressure. The implications of these results for deep operational diving are discussed.     

Electrical stimulation of acupuncture points enhances gastric myoelectrical activity in humans

OBJECTIVE: Acupuncture is known to enhance gastric motility. Electrical acustimulation has been shown to reduce gastric tachyarrhymia in vection-induced motion sickness. The aim of this study was to investigate the effect of electrical stimulation of acupuncture points on gastric myoelectrical activity in healthy humans. METHODS: Nine healthy native Chinese were studied. Gastric myoelectrical activity was recorded using surface electrogastrography (EGG). The EGG recording was made in the fasting state, in a study period during which acupuncture points were electrically stimulated continuously, and in a recovery period after stimulation. The percentage of regular slow waves was assessed by computing the percentage of 2 to 4 cycles per minute slow waves in the EGG. RESULTS: Electrical stimulation significantly increased the percentage of regular slow waves, which was sustained in the recovery period. The increase of the regular slow wave activity resulted from the normalization of arrhythmia. CONCLUSION: Electrical stimulation of acupuncture points may enhance the regularity of gastric myoelectrical activity and may be an option for treatment of gastric dysrhythmia.     

The quantitative analysis of glass by emission spectrography: a six element survey

During two dive series, one to 132 fsw and one to 210 fsw, Doppler ultrasonic bubble detectors were used to monitor venous gas bubbles in divers during decompression and for 30 min thereafter. Various decompression schedules were used. Bubble scores were evaluated by independent listerners to tape recordings in a blind manner. A significant increase in bubble scores throughout the stages of decompression and postdecompression was demonstrated as well as a statistically significant relationship between bubble score and decompression sickness. A reduction in mean bubble score was found in divers who made an additional deep decompression stop that was unrelated to the extension of the decompression time. The implications of these findings are discussed.     

Antisense WT1 transcription parallels sense mRNA and protein expression in fetal kidney and can elevate protein levels in vitro

The intensity of a pain-only decompression sickness (DCS) symptom with respect to time at altitude increases, peaks, and then declines in some cases. A similar pattern is also seen in a graph of the probability density function [f(t)] for DCS. The f(t) is the proportion of DCS per unit time with respect to time at altitude. The integration of f(t) with respect to time provides the cumulative probability of DCS [P(DCS)]. We suspect that the perceived intensity of pain with a given stimulus intensity is related to the P(DCS); it may be related to the intensity of the stimulus to a power (alpha). Our stimuli are defined as pressure ratio [PR = (phi P1N2/ P2)-11] or pressure difference [delta P = phi P1N2-P2], where phi P1N2 is the N2 partial pressure calculated in the 360 min half-time (t1/2) compartment or t1/2 is estimated with other parameters and P2 is ambient pressure after the ascent. Both stimuli represent a potential released volume of gas. We tested the null hypothesis that alpha > 1 was no better than alpha = 1 in PR alpha and delta P alpha in a log logistic survival analysis of 1085 exposures in hypobaric chambers. The log likelihood number increased from -1198 for alpha = 0 for the null model to -724 for PR alpha when alpha = 3.52 with a 42 min t1/2 and -714 for delta P alpha when alpha = 8.44 with a 91 min t1/2. We conclude that the improvement in our expressions for decompression dose with alpha > 1 is not by random chance and that alpha may link the physics of gas evolution to the biology of pain perception. Because of our empirical approach, we do not exclude other possible interpretations.     

Indicators of postoperative pain in cats and correlation with clinical criteria

OBJECTIVE: To identify clinical indicators that may help identity postoperative pain in cats after ovariohysterectomy. ANIMALS: Healthy, laboratory animal source cats. PROCEDURE: Clinical indicators of pain were identified, and relief from pain in response to butorphanol was studied in 5 groups of cats. 10 cats had 1 hour of general anesthesia only, followed by recovery without additional medication. 10 cats had general anesthesia and ovariohysterectomy, followed by recovery without additional medication. 10 cats had general anesthesia, ovariohysterectomy, and postoperative administration of 0.1 mg of butorphanol/kg of body weight. Another 10 cats had general anesthesia, ovariohysterectomy, and postoperative administration of 0.3 mg butorphanol/kg. 10 cats received 0.1 mg of butorphanol/kg, IM, only. Samples and recorded data were obtained before, during, and after the anesthesia period. Clinical variables measured included heart rate, blood pressure, respiratory rate, rectal temperature, PCV, and blood glucose concentration. Results were compared with changes in norepinephrine, epinephrine, and cortisol concentrations. RESULTS: Cats that did not receive analgesics had higher cortisol concentration than did cats without surgery and cats that received butorphanol after surgery. Systolic blood pressure measured by ultrasonic Doppler was found to be predictive of cortisol concentration, using a multiple linear regression model. CONCLUSIONS: Cortisol concentration increased in response to surgical stress and pain, and this increase was diminished by use of butorphanol. CLINICAL RELEVANCE: Systolic blood pressure was the best clinical predictor of postoperative pain.     

Effect of microbial inoculation of high-moisture corn on fermentation characteristics, aerobic stability, and cattle performance

Two trials were conducted to evaluate the effects of microbial inoculation for preservation of high-moisture corn (HMC). In Trial 1, three concrete, upright silos were filled with 83 t of HMC that was treated with either a dry microbial inoculant (DI), reconstituted liquid microbial inoculant (RLI), or an untreated control (CON). The CON or RLI-treated HMC were placed in two silos in Trial 2. Both inoculants were applied to supply 2 x 10(6) colony-forming units (cfu)/g of wet corn. Samples were collected from the bottom two doors of each silo for 21 d (Trial 1) or 40 d (Trial 2) postensiling and during feedout to evaluate fermentation changes over time. Dacron bags buried at four elevations within each silo were recovered during feedout to determine DM losses and chemical composition changes during the fermentation period. In both trials, concentrations of soluble N (SN) increased over time. Acetate content was higher in DI than in CON in Trial 1 and ethanol was greater (P < .05) for RLI than for CON in Trial 2. Acidity declined faster (P < .05) and soluble carbohydrate was reduced for RLI during the feedout phase in Trial 2. Dry matter recovery tended to be greater with CON (P < .10) than with RLI-treated HMC in Trial 2. Aerobic stability was evaluated on corn from silos in Trial 2 by placement in styrofoam containers. Temperature and microbial numbers increased (P < .05) during the 5-d aerobic incubation period for both HMC treatments. The population of microorganisms was greater for RLI on d 3 than for CON.(ABSTRACT TRUNCATED AT 250 WORDS)     

13-week subchronic oral toxicity study of phaffia colour in F344 rats

A 13-week subchronic oral toxicity study of phaffia colour was performed in both sexes of F344 rats by feeding of CRF-1 powder diet containing 0, 0.2, 0.6, 1.7 and 5%. Rats were randomly divided into 5 groups, each consisting of 10 males and 10 females. No animals died during the administration period. There were no treatment-related changes in body weight gain, hematological and blood biochemical examination. No treatment-related histopathological changes were also observed in any dosed groups. These findings indicate that the treatment of 5% phaffia colour in diet for 13 weeks does not cause any toxicological changes in rats.