Vaporizer overfilling.
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Biomedical subjects
Publications and source records attributed to D B Craig.
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This study correlates the prevalent oral disease findings in 390 patients seropositive for human immunodeficiency virus type 1 (HIV-1) with their level of staging (Walter Reed) and depletion of peripheral helper T lymphocytes (CD4+). Chronic lymphadenopathy of the head and neck was a common finding (59.2%) that occurred early in staging progression and did not correlate with depression of helper T-cell levels. Of the three prevalent oral disease findings (oral hairy leukoplakia (OHL), candidiasis, necrotizing ulcerative gingivitis [NUG]) only OHL and NUG were significantly correlated with helper T-cell depletion. The occurrence of visually detectable OHL and NUG corresponds to depletion of peripheral helper T-lymphocyte values in a range of 157 to 299 cells/mm3. This range may represent a more accurate value for biologically significant lymphocyte depletion than the Walter Reed value of 400 cells/mm3. The presence of OHL showed a weak statistical correlation with staging progression, indicating deteriorating immunoregulation. No cases of Kaposi's sarcoma or other HIV-1-associated oral diseases were observed in the sample population, regardless of the patient's staging category or peripheral helper T-lymphocyte count.
HIV-infected individuals in both early and late stages of HIV disease were evaluated over 2 years to assess temporal trends and determinants of disease progression. The Walter Reed (WR) staging system was used to categorize patients into an early-stage cohort (WR Stages 1 and 2, N = 1183) and a late-stage cohort (WR Stage 5, N = 260) based on the initial clinical evaluation. Progression was defined as the occurrence of Stage 5 disease or beyond for the early cohort and Stage 6 disease or beyond for the late cohort. The cumulative incidence of progression was 15.7% (137 events) for the early-stage cohort, and 53.7% (85 events) for the late-stage cohort. Baseline CD4+ T lymphocyte (T4) count was the most significant marker of progression: 26% of WR Stage 1 or 2 patients with T4 lymphocytes below 500/mm3 progressed, compared with 12% with T4 lymphocytes at or above 500/mm3. In late-stage individuals, 83% with T4 lymphocytes under 200/mm3 progressed, compared with 27% with T4 lymphocytes at or above 200/mm3. Older age was associated with progression in both early- and late-stage groups. Differences in the rates of disease progression were not significant between blacks and whites or between men and women. Two-year rates of progression among the late-stage patients dropped from 78 to 47% between 1986 and 1988. This contrasted with progression rates in the early-stage cohort, which remained stable: 18% for those entering follow-up in 1986 and 17% for those entering follow-up in 1988. These data indicate a significant slowing of HIV disease progression rates and mortality rates among individuals with late-stage disease that is temporally associated with the increased availability and use of therapies. With control of T4 lymphocyte count, age, and calendar time, neither gender nor race was significantly associated with progression in either early- or late-stage patients.
Cytochrome c binds ATP with marked specificity at a site that contains the evolutionarily invariant residue Arg-91. The binding of ATP to this site was studied using equilibrium gel filtration, equilibrium dialysis and affinity chromatography. At physiological ionic strength the affinity is such that the major change in occupancy coincides with the normal cellular ATP concentration range, and the degree of saturation is proportional to the ratio of [ATP]/[ADP]. The specificity of binding at this site is more a function of the degree of phosphorylation of the nucleotide, than of the nature of the nucleoside moiety. Thus under physiological conditions the degree of occupancy of this site is proportional to the energy state of the cell, providing a means for the regulation of the respiratory chain which is sensitive to cytoplasmic ATP levels.
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Recrudescent pulmonary melioidosis developed in two patients 12 and 16 years after their last travels to an endemic area. In one, a clinically silent prostatic abscess may have been the focus; and in both, the diagnosis was difficult to make even when the laboratory was notified of the possibility of infection with Pseudomonas pseudomallei. Recrudescent melioidosis should be considered in febrile patients who have been in endemic areas regardless of the interval from last exposure to the development of disease.
To define the effect of alkalinization of bupivacaine 0.5% in subclavian perivascular brachial plexus blockade, the time to onset, time to peak effect, and 6-hour regression of sensory and motor blockade were determined. Sixty physical status ASA I and II patients were randomly allocated to one of two groups and a double-blind design was used: group I (n = 30) received bupivacaine 0.5% (pH, 5.5) 3 mg/kg, while group II (n = 30) received alkalinized bupivacaine 0.5% (pH, 7.05-7.15) 3 mg/kg. Onset and regression of sensory blockade were determined by pinprick in the C4-T2 skin dermatomes, while motor blockade was assessed using a scheme of proximal to distal muscle group paralysis. Time to onset of sensory blockade (group I, 4.0 +/- 1.2 min; group II, 3.6 +/- 0.9 min) and time to peak sensory effect (group I, 17.7 +/- 1.8 min; group II, 16.3 +/- 1.8 min) did not differ significantly between the groups. Similarly, no difference in time to onset of motor blockade (group I, 6.9 +/- 1.7 min; group II, 6.3 +/- 1.5 min) or time to peak motor effect (group I, 18.1 +/- 1.9 min; group II, 15.1 +/- 1.9 min) was observed. Regression of postoperative sensory and motor blockade was similar in both groups. It is concluded that alkalinization of bupivacaine 0.5% solutions does not confer any added clinical advantage in subclavian perivascular brachial plexus blockade when compared with commercially available bupivacaine.
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Constant flow ventilation (CFV) maintains normal gas exchange in apneic dogs and has potential clinical application during thoracic surgery or pulmonary edema. We compared CFV and intermittent positive pressure ventilation (IPPV) in five healthy, anesthetized, (fentanyl, diazepam, and nitrous oxide) and paralyzed patients undergoing nonthoracic operations. Constant flow ventilation was delivered at a total flow of 0.9-1.6 L . kg-1 . min-1 (nitrous oxide-oxygen at 1:1) into two tubes of 2.5-3.5 mm inner diameter attached to each side of an 8-9 mm inner diameter orotracheal tube (OTT). Under bronchoscopic guidance, the CFV-OTT was advanced to position each ventilating tube at a mainstem bronchial orifice. Gas exhausted through the OTT lumen. If intrathoracic pressure exceeded a preset limit, a solenoid valve automatically interrupted gas flow to the patient to prevent barotrauma. Compared to IPPV, during CFV for up to 30 min average PaCO2 increased to 69.2 +/- 14.5 from 35.9 +/- 2.9 mm Hg, reflecting a calculated alveolar ventilation (VA) of 46 +/- 22% of the eucapnic level. We suggest that a technique combining CFV at lower flow rates with IPPV may prove clinically useful by allowing decreased tidal volume and inspiratory pressure while maintaining normal VA.
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An adult with spontaneous septic arthritis due to Branhamella catarrhalis is described and the literature reviewed. B. catarrhalis is an organism similar to the Neisseria species and has been implicated in a variety of systemic infections. As it is frequently resistant to penicillin, cephamycins or third generation cephalosporins may be the empiric drugs of choice for infections caused by this organism.
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Agent-specific keyed vapourizer filling devices were designed to ensure that an anaesthetic vapourizer is filled with the correct agent. Since there appear to be no reports of possible loss of volatile agent or operating room pollution resulting from either the design or patterns of use of these devices, measurements were made with three anaesthetic agents and two methods of use. First, two bottles each of methoxyflurane, enflurane and halothane were fitted with a suitable filling device and the weight of agent lost from each bottle over six weeks was measured. Bottle #1 of each agent remained without agitation between weighings; bottle #2 was tipped to mimic filling of a vapourizer. Weight loss over the six week period was 2.76 and 3.15 per cent of the halothane, 2.22 and 2.43 per cent of the enflurane, and 0.58 and 0.96 per cent of the methoxyflurane, for bottles #1 and #2, respectively. Second, pollution was measured with an infra-red analyser for halothane, using bottles #1 and #2, as described above, and a third bottle on which the filling device was replaced by the screw-on cap after each filling of the vapourizer. Vapour loss was undetectable for bottle #1, between 25 and 30 ppm for bottle #2, and between 350 and 400 ppm for bottle #3. Thus, although the design of the filling devices results in loss of the anaesthetic agent, this loss represents potential pollution only when the device is replaced by the screw-on cap between use. Therefore, when using filling devices, these should be left on the bottle of volatile agent between fillings to decrease operating room pollution.