Early central nervous system response to HIV infection: sleep distortion and cognitive-motor decrements

OBJECTIVE

To repeat and extend findings suggesting that sleep disturbance, excessive daytime sleepiness, and degraded cognitive-motor abilities may be early markers of central nervous system (CNS) involvement in HIV infection.

DESIGN

A controlled, cross-sectional, prospective analysis.

SETTING

Clinical research center at a teaching hospital and a military health research center.

SUBJECTS

Twenty-three HIV-positive (mean CD4+ count, 387 +/- 162 x 10(6)/l) and 13 seronegative men who were Naval personnel or participants of the University of California, San Diego HIV Neurobehavioral Research Center.

MAIN OUTCOME MEASURES

Nocturnal and daytime sleep electroencephalogram, electromyogram, and electrocardiogram. Simple and complex cognitive-motor performance assessed via computerized tasks.

RESULTS

Comparison of sleep parameters based on HIV status, length of time infected, zidovudine use, and CD4+ count indicated that CD4+ T cells > 400 x 10(6)/l were associated with a distortion in nocturnal sleep characterized by increased stages 3 and 4 non-rapid eye movement (i.e., slow-wave) sleep in the latter portion of the night and reduced nocturnal awakenings. HIV-positive patients were no sleepier in the daytime than controls. Cognitive-motor performance revealed deficits in both accuracy and efficiency for HIV-positive patients.

CONCLUSION

Asymptomatic HIV-positive patients with CD4+ counts > 400 x 10(6)/l demonstrate a statistically significant increase in slow-wave sleep during the latter portion of the night and less arousability. CD4+ lymphocyte count in the early phases of HIV infection appears to differentiate between various levels of HIV disease progression with respect to certain CNS measurements of nocturnal sleep and cognitive-motor performance. Sleep structure distortion remains one of the earliest and most consistently replicable physiological signs of HIV infection. This distortion may provide a link to immune function, disease progression, and cognitive-motor disability in HIV infection.

Does spinal anesthesia result in a more complete sympathetic block than that from epidural anesthesia?

BACKGROUND

Spinal and epidural injection of local anesthetics are used to produce sympathetic block to diagnose and treat certain chronic pain syndromes. It is not clear whether either form of regional anesthesia produces a complete sympathetic block. Spinal anesthesia using tetracaine has been reported to produce a decrease in plasma catecholamine concentrations. This has not been demonstrated for epidural anesthesia in humans with level of anesthesia below C8. One possible explanation is that spinal anesthesia results in a more complete sympathetic block than epidural anesthesia. To examine this question, a cross-over study was performed in young, healthy volunteers.

METHODS

Ten subjects underwent both spinal and epidural anesthesia with lidocaine (plain) on the same day with complete recovery between blocks. By random assignment, spinal anesthesia and epidural anesthesia were induced via lumbar injection. Before and 30 min after local anesthetic injection, a cold pressor test (CPT) was performed. Blood was obtained to determine epinephrine and norepinephrine plasma concentrations at four stages: (1) 20 min after placing peripheral catheters, (2) at the end of a 2-min CPT (before conduction block), (3) 30 min after injection of epidural or spinal lidocaine, and (4) at the end of a second CPT (during anesthesia). Mean arterial pressure, heart rate, noninvasive cardiac index, and analgesia to pin-prick were monitored.

RESULTS

Neither spinal nor epidural anesthesia changed baseline resting values of catecholamines or any hemodynamic variable, except heart rate, which was slightly decreased during spinal anesthesia. Median level of analgesia was T4 during spinal and T3 during epidural anesthesia. CPT before conduction block reliably increased heart rate, mean arterial pressure, cardiac index, epinephrine, and norepinephrine. Conduction block attenuated the increase in response to CPT only in mean arterial pressure (spinal and epidural) and cardiac index (spinal only). Neither technique blocked the increase in heart rate, norepinephrine, or epinephrine to CPT.

CONCLUSIONS

Spinal anesthesia did not result in a more complete attenuation of the sympathetic response to a CPT than did epidural anesthesia. In response to the CPT, spinal anesthesia blocked the increase in cardiac index, and epidural anesthesia resulted in a decrease in total peripheral resistance compared to the pre-anesthesia state. The differences between the techniques are not significant and are of uncertain clinical implications.

Structure and properties of aluminum-containing adjuvants

This chapter is concerned with the identification, characterization, and behavior of aluminum-containing adjuvants with proteins and anions similar to those occurring in vaccines and interstitial fluid. Aluminum-containing adjuvants referred to commercially as aluminum hydroxide have been identified as poorly crystalline aluminum oxyhydroxide with the structure of the mineral boehmite. Relevant properties of this material include its high surface area and its high pI, which provide the adjuvant with a high adsorptive capacity for positively charged proteins. Aluminum phosphate and alum-precipitated adjuvants may be classified as amorphous aluminum hydroxyphosphate with little or no specifically adsorbed sulfate. Variations in the molar PO4/A1 ratio of amorphous aluminum hydroxyphosphates result in PI values that range from 5 up to 7; the materials are negatively charged at a physiological pH of 7.4. The amorphous nature of these compounds gives them high surface area and high protein adsorptive capacity for positively charged proteins. Observations on the interactions of anions and charged proteins with charged adjuvant surfaces have provided a framework for predicting behavior of complex systems of vaccines and for designing specific combinations of adjuvants and antigens to optimize the stability and efficacy of vaccines.

The replication of a necrogenic cucumber mosaic virus satellite is temperature-sensitive in tomato

Lethal necrosis development in tomato plants infected with cucumber mosaic virus (CMV) strain D containing the necrogenic satellite D-CARNA 5 and held at 32 degrees C is shown to be impaired. CARNA 5 accumulation in tomato at 32 degrees C is reduced about 100-fold compared to accumulation in plants held at 24 degrees C, while viral RNA accumulation is reduced about 5-fold. CMV-infected tomato held for 3 days at 24 degrees C prior to shift to 32 degrees C do not develop lethal necrosis. Longer incubations at 24 degrees C prior to shift to 32 degrees C allow necrosis to develop. CMV-infected plants held for up to 4 weeks at 32 degrees C required an additional 8-10 days at 24 degrees C to develop necrosis. Necrogenic CMV-infected plants held at 24 degrees C and analyzed 3 days p.i. contained detectable amounts of ss- and ds-CARNA 5; upon shift to 32 degrees C, such CARNA 5 declined to undetectable levels and lethal necrosis did not occur. There appear to be temperature-sensitive factors that are required for efficient satellite replication which are not required for efficient viral RNA replication. Whether these factor(s) are of host or satellite origin is uncertain.

Contribution of electrostatic and hydrophobic interactions to the adsorption of proteins by aluminium-containing adjuvants

The effect of ionic strength and ethylene glycol on the adsorption of bovine serum albumin (BSA) or lysozyme by a commercial aluminium hydroxide or aluminium phosphate adjuvant was studied at pH 7.4 and 25 degrees C. The adsorption of BSA by aluminium hydroxide adjuvant and lysozyme by aluminium phosphate adjuvant was found to be inversely related to ionic strength. This indicates that electrostatic attractive forces contribute to adsorption. The adsorption of lysozyme by aluminium phosphate adjuvant was reduced by the addition of ethylene glycol. However, no change in the adsorption of BSA by aluminium hydroxide adjuvant was noted when up to 40% ethylene glycol was present. This behaviour indicates that hydrophobic forces contribute to the adsorption of lysozyme but not of BSA. However, virtually no adsorption was observed when the protein and the adjuvant had the same surface charge. Thus, attractive forces may not be sufficient to produce adsorption of an antigen by an aluminium-containing adjuvant if electrostatic repulsive forces are present.

Differential epidural block. Does the choice of local anesthetic matter?

BACKGROUND AND OBJECTIVES

It is well established that spinal anesthesia results in a differential block to the sensations of pinprick and cold temperature discrimination. However, the existence of differential block during epidural anesthesia has not always been accepted. Recently, it has been shown that lumbar epidural anesthesia with chloroprocaine and lidocaine produces a differential block to pinprick and cold sensation. The purpose of this study was to determine if the choice of local anesthetic used for epidural anesthesia has any influence on the relative levels of anesthesia, analgesia, and cold sensation.

METHODS

The authors studied nine healthy subjects; each was studied three times and received one of three local anesthetics (0.75% bupivacaine, 2% lidocaine, and 3% chloroprocaine) via an epidural catheter placed into the second or third lumbar epidural space. The authors tested the following modalities compared to an unblocked dermatome: anesthesia, loss of sensation to pinprick; analgesia, loss of an equally sharp sensation to pinprick; and cold sensation, loss of cold sensation to alcohol.

RESULTS

Twenty minutes after injection of the local anesthetic, zones of differential sensory block existed for all three agents tested. Anesthesia and analgesia were the most caudad and cephalad, respectively, while loss-to-cold sensation was found to be between these two levels. There was no significant difference in the dermatomal level achieved among the three local anesthetics tested. Sensory testing data observed 10 minutes later showed that no significant change had occurred.

CONCLUSIONS

This study reaffirms the existence of differential sensory block during epidural anesthesia and establishes that the observed differential block appears to be independent of the local anesthetic used.

Measuring impulsivity and examining its relationship to delinquency

A multimethod, multisource assessment of impulsivity was conducted in a sample of more than 400 boys who were members of a longitudinal study of the development of antisocial behavior. Exploratory and confirmatory factor analysis of the 11 different impulsivity measures revealed two impulsivity factors: Cognitive and Behavioral. Cognitive and behavioral impulsivity had similar correlations with socioeconomic status. Cognitive impulsivity was more strongly related to IQ than was behavioral impulsivity. Behavioral impulsivity was more strongly related to delinquency at ages 10 and 12-13 than was cognitive impulsivity. Consistent with theoretical prediction, our results also indicate that behavioral impulsivity was especially related to serious delinquency that is stable over time.

Functional recovery of stunned myocardium is greater with halothane than fentanyl anaesthesia in dogs

We have compared the effects of halothane or fentanyl on recovery of regional myocardial function in the postischaemic ventricle in dogs. The animals were followed for 120 min during reperfusion after 15-min of occlusion of the left anterior descending coronary artery. After 120 min of reperfusion, the fentanyl group had recovered only 54% and 50% of regional contractility and systolic shortening (P < 0.05), respectively, compared with halothane (63% and 86%). Intramyocardial tissue pressure was less than baseline 60 min after reperfusion in the fentanyl group (P < 0.05), whereas the halothane group had returned to control values. We conclude that halothane is more effective than fentanyl in attenuating regional myocardial dysfunction associated with transient episodes of ischaemia.

Endoscopic urethroplasty of posterior urethral avulsion

OBJECTIVES

Traumatic avulsion of the posterior urethra represents a challenging reconstructive problem that traditionally has been managed by the transpubic or transperineal approach. We report the advantages of endourologic techniques to reconstruct short posterior urethral disruptions based on the principles of establishing proximal urethral control and balloon dilation of the newly constructed urethra.

METHODS

Endourologic urethroplasty consists of: (1) antegrade flexible cystoscopy or antegrade passage of a Goodwin sound, (2) retrograde urethrotomy to light or to tip of Goodwin sound, facilitated by C-arm fluoroscopy, (3) establishment of urethral continuity by passage of a guide wire, (4) balloon dilation of the newly established urethra to 24 to 30 F over a length of 4 cm, and (5) long-term urethral stenting (4 to 8 weeks) with a silicone Foley catheter.

RESULTS

In four men initially managed by suprapubic cystostomy, endourologic reconstruction was performed. The mean blood loss was 250 mL, and mean length of hospitalization was 5.4 days. All patients were continent and three were potent over a mean follow-up of 10.5 months. Uroflowmetric monitoring showed satisfactory voiding patterns with subsequent minor endoscopic revisions required in three patients.

CONCLUSIONS

The technical advantages of this method include stabilization and identification of the proximal urethra, intraoperative shortening of the urethral gap to facilitate the urethrotomy, and radial distention of the urethra by balloon dilation. We conclude that endourologic methods provide a safe and effective initial treatment of urethral avulsion.

Subjective experiences of anesthesiologists undergoing epidural anesthesia

BACKGROUND AND OBJECTIVES

This study reports subjective experiences of nine anesthesiologists undergoing three consecutive epidural anesthetics.

METHODS

Eight anesthesiologists and one nurse anesthetist, all ASA physical status 1, underwent three lumbar epidural anesthetics as part of another study. Epidural catheters were inserted via a 17-gauge Tuohy needle without sedation after local anesthesia with pH adjusted lidocaine at the second, third, or fourth lumbar interspace. Three local anesthetics (2% lidocaine HCl, 3% chloroprocaine HCl, and 0.75% bupivacaine HCl) were administered each separated by at least 48 hours. The local anesthetic was incrementally injected via the epidural catheter to achieve at least a T-1 dermatome level of analgesia. Each subject completed a written questionnaire at the end of the study regarding their experience.

RESULTS

Most of the subjects (7 of 9) had no prior epidural anesthesia. Eight of nine subjects experienced at least one paresthesia during catheter insertion; this was uniformly described as a "poorly localized burning sensation," radiating to the hip or leg. All subjects reported difficulty taking a deep breath and coughing with a T-1 level of analgesia. Eight of nine subjects reported dysphoria during lidocaine epidural anesthesia. Eight of nine subjects reported moderate back pain after dissipation of chloroprocaine epidural anesthesia.

CONCLUSIONS

All volunteers stated that they would change their anesthetic practice as a result of participation in this study. They believed that having experienced an epidural anesthetic made them better qualified to prepare patients for this anesthetic technique.

Home care coverage improvements anticipated under health care reform

Health care reform will affect home care and hospice providers in ways that are as yet unclear. One thing that is certain, however, is that reform will open new doors for providers under both federal and private reimbursement systems. This review of current coverage and existing opportunities gives a background from which providers can look to the future.

Measuring impulsivity and examining its relationship to delinquency

A multimethod, multisource assessment of impulsivity was conducted in a sample of more than 400 boys who were members of a longitudinal study of the development of antisocial behavior. Exploratory and confirmatory factor analysis of the 11 different impulsivity measures revealed two impulsivity factors: Cognitive and Behavioral. Cognitive and behavioral impulsivity had similar correlations with socioeconomic status. Cognitive impulsivity was more strongly related to IQ than was behavioral impulsivity. Behavioral impulsivity was more strongly related to delinquency at ages 10 and 12-13 than was cognitive impulsivity. Consistent with theoretical prediction, our results also indicate that behavioral impulsivity was especially related to serious delinquency that is stable over time.

Effect of protein adsorption on the surface charge characteristics of aluminium-containing adjuvants

The effect of adsorbing two model proteins, bovine serum albumin and lysozyme, on the point of zero charge of aluminium-containing vaccine adjuvants was studied. At physiological pH, the adsorption of the negatively charged albumin (isoelectric point = 5.0) by aluminium hydroxide adjuvant (point of zero charge = 11.1) resulted in a decrease in the point of zero charge. In contrast, the adsorption of positively charged lysozyme (isoelectric point = 9.6) by the negatively charged aluminium phosphate adjuvant (point of zero charge = 5.0) resulted in an increase in the point of zero charge. The surface charge characteristics of the aluminium-containing adjuvant dominated at low protein coverage. In contrast, the surface charge characteristics of the adsorbed protein dominated at high protein coverage. Therefore, the physicochemical properties of the antigen-adjuvant complex and not the adjuvant alone should be considered during vaccine preparation.

Relationship between protein adsorptive capacity and the X-ray diffraction pattern of aluminium hydroxide adjuvants

Thermal treatment during the preparation of aluminium hydroxide adjuvants affects the primary crystallite size of the adjuvant. The primary crystallite size can be characterized by the line broadening of the (020) reflection of the X-ray diffraction pattern. Studies of protein adsorption using bovine serum albumin as a model protein revealed a direct relationship between the albumin adsorptive capacity and the width at half height (WHH) of the (020) reflection in the X-ray diffraction pattern.

Does the choice of local anesthetic affect the catecholamine response to stress during epidural anesthesia?

BACKGROUND

Previous work has established that 2-chloroprocaine epidural anesthesia has no effect on circulating plasma epinephrine concentrations in young, healthy, resting volunteers, and results in a decrease in norepinephrine concentration only when a level of analgesia to pinprick of C-8 is reached. The current study was performed to evaluate the possibility that this finding is unique to 2-chloroprocaine.

METHODS

Nine healthy volunteers were studied on three occasions at least 48 h apart; each received three local anesthetics (0.75% bupivacaine, 2% lidocaine, and 3% 2-chloroprocaine, all without epinephrine). After placement of lumbar epidural and central venous catheters, blood samples were drawn from the central venous catheter at the following stages: (1) 20 min after catheter placement (baseline), (2) during the first cold pressor test (CPT; hand held in an ice water bath for 90 s), (3) 20 min after reaching epidural analgesia to T-1 level of analgesia, and (4) during a second CPT (epidural analgesia to T-1). Monitoring consisted of noninvasive cardiac output (impedance), noninvasive blood pressure, and EKG.

RESULTS

Extensive epidural block (stage 3) altered measured variables only minimally with respect to resting baseline state. During stage 2 (first CPT), mean arterial pressure (MAP), heart rate (HR), cardiac index (CI), epinephrine, and norepinephrine increased. During stage 4 (second CPT), increases in HR and CI were not attenuated by any of the three local anesthetics. Increases in MAP were attenuated by epidural anesthesia with all three local anesthetics. Bupivacaine and 2-chloroprocaine epidural anesthesia significantly attenuated increases in plasma catecholamines, but lidocaine epidural anesthesia did not.

CONCLUSIONS

Epidural anesthesia with all three local anesthetic agents tested resulted in an incomplete sympathectomy in the resting state in healthy young men, judged by plasma catecholamine concentrations and cardiovascular variables minimally changed from resting baseline. Lidocaine epidural anesthesia did not attenuate the catecholamine response to CPT, indicating decreased blockade of sympathetic efferent neural traffic compared with bupivacaine and chloroprocaine epidural anesthesia.

The effect of aluminum hydroxide dissolution on the bleeding of aluminum lake dyes

The effect of pH on the bleeding of FD&C yellow No. 5 aluminum lake and FD&C red No. 40 aluminum lake was investigated. The pH-bleeding profiles corresponded to the pH-solubility profile of aluminum hydroxide. The similarity of the bleeding profiles of both lake dyes and the pH-solubility profile of aluminum hydroxide indicates that pH related bleeding, other than that occurring by competition with anions, is a result of dissolution of the aluminum hydroxide substrate. This dissolution is related to the properties of the substrate rather than to the structure of adsorbed dye.