Variation in resistance of natural isolates of Escherichia coli O157 to high hydrostatic pressure, mild heat, and other stresses

Strains of Escherichia coli O157 isolated from patients with clinical cases of food-borne illness and other sources exhibited wide differences in resistance to high hydrostatic pressure. The most pressure-resistant strains were also more resistant to mild heat than other strains. Strain C9490, a representative pressure-resistant strain, was also more resistant to acid, oxidative, and osmotic stresses than the pressure-sensitive strain NCTC 12079. Most of these differences in resistance were observed only in stationary-phase cells, the only exception being acid resistance, where differences were also apparent in the exponential phase. Membrane damage in pressure-treated cells was revealed by increased uptake of the fluorescent dyes ethidium bromide and propidium iodide. When strains were exposed to the same pressure for different lengths of time, the pressure-sensitive strains took up stain sooner than the more resistant strain, which suggested that the differences in resistance may be related to susceptibility to membrane damage. Our results emphasize the importance of including stress-resistant strains of E. coli O157 when the efficacy of a novel or mild food preservation treatment is tested.

Developers and evaluation of interactive health communication applications. The Science Panel on Interactive Communications and Health

BACKGROUND

Developers of Interactive Health Communication (IHC) are capable of providing great benefit by creating interactive programs that serve to protect and improve health. Conducting proper evaluation of these programs will ensure that they achieve these goals more successfully.

CONCLUSIONS

This article seeks to inform developers of IHC about which types of evaluation are most important to include as a part of the development process and to examine the ways in which such evaluation can be implemented to benefit the producers--and ultimately, the consumers--of IHC.

Thoracodorsal nerve conduction study

There is no nerve conduction study for the thoracodorsal nerve in the literature. A conduction study for this nerve is described. Thirty healthy adults (16 males) with a mean age of 41.5 +/- 10.6 (range, 22-63) years were studied. The thoracodorsal nerve was stimulated at axilla and Erb's point with recording over the latissimus dorsi. The latency was 1.9 +/- 0.4 (range, 1.2-2.7) ms and 3.6 +/- 0.4 (range, 2.8-4.5) ms for the axillary and Erb's stimulations, respectively. The amplitude of the compound muscle action potential was 4.1 +/- 1.8 mv on the right and 3.9 +/- 1.4 mv on the left. The compound muscle action potential ratio was 0.8 +/- 0.12 (range, 0.55-0.99). This study may be useful to evaluate the integrity of the thoracodorsal nerve and to assist in the diagnosis and prognosis of brachial plexus injury.

Hemodialysis vascular access: variable thrombus-free survival in three subpopulations of black patients

Hemodialysis vascular access-related problems account for most hospitalizations in chronic hemodialysis patients. Although some co-morbid risk factors for early fistula failures have been described, a great deal of unknown exists as to why access survival is favorable in some patients. In this longitudinal study, fistulae patency and thrombosis episodes were monitored from placement date in three groups of end-stage renal disease (ESRD) patients who have been on dialysis for > or =90 days. Thirty-six patients (29 male; 80%) with a mean age of 42+/-2 years were monitored. The groups consisted of eight patients with biopsy-confirmed focal segmental glomeruloscierosis (FSGS), 13 with acquired immunodeficiency syndrome-related nephropathy (human immunodeficiency virus [HIV]), and 15 with hypertensive ESRD (hypertensive nephrosclerosis [HTN]) who served as controls. Diabetics and patients aged > or =64 years were excluded. Twenty-five of 36 (69%) fistulae were prosthetic (AVG), while 11 (31%) were native (AVF). The FSGS group was more likely to have an AVG (87.5%), while 54% of the HIV group had an AVG. The thrombosis event rate was significantly greater among the FSGS patients (3/patient-year) than the HIV (0.15/patient-year) and HTN (0.5/patient-year) patients (P < 0.0001 and P < 0.002, respectively). The mean thrombosis-free duration for both AVG and AVF among the HIV and HTN groups were 318.5+/-17 days and 311.7+/-22.5 days, respectively. These were significantly greater than in the FSGS group (26.5+/-7 days; P < 0.0001). The cumulative 1-year patency rate for AVG among the HIV and HTN groups was 85% and 65%, respectively, while that of the FSGS group was 0%. Kaplan-Meier hazard analysis showed that all groups were at risk of access thrombosis as time progressed, but the FSGS group had the highest risk of access thrombosis, which began from the date of placement and increased exponentially with time. The increased thrombosis rate among the patients in the FSGS group correlated with their weight (R = 0.8, P = 0.003) and pre-ESRD 24-hour urinary protein excretion (R = 0.9, P = 0.001). The HIV status appeared to confer enhanced hemodialysis access survival. This may be related to the high rate of native fistulae placement and favorable vascular reactivity to shear stress. Accelerated atherosclerosis and small caliber vessels may be responsible for the poor fistulae outcome among the FSGS group. More studies will be necessary to further explore these findings.

Cardiopulmonary and arterial baroreflex-mediated control of forearm vasomotor tone is impaired after acute stroke

BACKGROUND AND PURPOSE

Elevated blood pressure (BP) levels are well recognized after acute stroke and are associated with increased BP variability. The underlying mechanisms producing such changes are unclear but may include abnormalities of baroreceptor-mediated control of heart rate and vasomotor tone. Lower body negative pressure (LBNP) can be used to assess the integrity of "low-pressure" cardiopulmonary and "high-pressure" arterial baroreceptor-derived responses by inducing nonhypotensive and hypotensive stimuli.

METHODS

Cardiovascular responses, including BP, heart rate, forearm blood flow, and forearm vascular resistance, to nonhypotensive and hypotensive LBNP were assessed in 13 consecutive stroke patients. Patients were studied within 72 hours of stroke (acute) and again at 10 to 14 days (subacute) and were compared with 13 control subjects individually matched for age, sex, and BP.

RESULTS

At an LBNP of -10 mm Hg, BP was unchanged in all groups, but a significant increase in forearm vascular resistance occurred only in the control group (11 U [interquartile range, 7 to 15]; P < .05) compared with stroke patients in the acute (9 U [3 to 14]; P = NS) or subacute phases (7 U [2 to 12]; P = NS). After LBNP at -40 mm Hg, the reductions in systolic BP levels were similar in all groups (control: -9 mm Hg [-16 to -3]; acute stroke: -9 mm Hg [-22 to 3]; subacute stroke: -7 mm Hg [-35 to 20]), as was the associated increase in heart rate (control: 8 bpm ([4 to 11]; acute stroke: 6 bpm ([1 to 12]; subacute stroke: 9 bpm [2 to 19]). However, forearm vascular resistance increased significantly only in control subjects (20 U [9 to 30]; P < .01).

CONCLUSIONS

The present study has identified abnormal vasomotor responses to LBNP after acute stroke, with an increase in FVR only being observed in control subjects in response to nonhypotensive and similar hypotensive levels of LBNP. In acute stroke patients, the stimulus of hypotensive LBNP appears to be compensated by an increase in cardiac output since there appears to be no increase in peripheral vascular resistance, unlike the changes seen in control subjects. However, the exact mechanisms for these changes are still unclear and are the subject of further study.

Reduced striatal vesicular monoamine transporters after neurotoxic but not after behaviorally-sensitizing doses of methamphetamine

Prior studies indicate long-term reductions of striatal dopaminergic markers after sustained, high dose methamphetamine exposures in vivo, suggesting a neurotoxic effect. We have reported lack of regulation of vesicular monoamine transporter type-2 expression, as opposed to other markers of striatal dopaminergic terminals, under conditions that alter dopaminergic transmission without synaptic terminal losses. In the present study, we evaluated the vesicular monoamine transporter and the neuronal membrane dopamine transporter in rat striata after in vivo exposure to neurotoxic or to intermittent, low dose (behaviorally-sensitizing, non-neurotoxic) methamphetamine administrations. Vesicular monoamine transporter binding was measured by autoradiography of (+)-[3H]dihydrotetrabenazine, the active isomer of (+/-)-[3H]dihydrotetrabenazine. (+)-Dihydrotetrabenazine bound to a homogeneous population of striatal sites in controls with a Kd of 1.5 nM and a Bmax of 3.8 fmol/microg protein. Neurotoxic methamphetamine treatment reduced both striatal vesicular monoamine transporter (-26%) and dopamine transporter (-39%) bindings. There were no changes after the non-neurotoxic treatment regimen. The vesicular monoamine transporter may thus be a valuable marker in the further clinical study of psychostimulant drug neurotoxicity.

Univariate analysis of tsetse habitat in the common fly belt of southern Africa using climate and remotely sensed vegetation data

Tsetse are vectors of trypanosomes that cause diseases both in humans and livestock. Traditional tsetse surveys, using sampling methods such as Epsilon traps and black screen fly rounds, are often logistically difficult, costly and time-consuming. The distribution of tsetse, as revealed by such survey methods, is strongly influenced by environmental conditions, such as climate and vegetation cover, which may be readily mapped using satellite data. These data may be used to make predictions of the probable distribution of tsetse in unsurveyed areas by determining the environmental characteristics of areas of tsetse presence and absence in surveyed areas. The same methods may also be used to characterize differences between tsetse species and subspecies. In this paper we analyse the distribution of Glossina morsitans centralis, Glossina morsitans morsitans and Glossina pallidipes in southern Africa with respect to single environmental variables. For G.m.centralis the best predictions were made using the average NDVI (75% correct predictions; range > 0.37) and the average of the maximum temperature (70% correct predictions; 27.0-29.2 degrees C). For G.m.morsitans the best prediction was given by the maximum of the minimum temperature (84% correct predictions; range > 18.8 degrees C), and for G.pallidipes, also by the maximum of the minimum temperature (86% correct predictions; range > 19.6 degrees C). The following paper compares a range of multivariate techniques for making predictions about the distribution of these species in the same region.

Mapping tsetse habitat suitability in the common fly belt of southern Africa using multivariate analysis of climate and remotely sensed vegetation data

The distribution of Glossina morsitans centralis, Glossina morsitans morsitans and Glossina pallidipes are described in part of southern Africa, using a range of multivariate techniques applied to climate and remotely sensed vegetation data. Linear discriminant analysis is limited in its predictive power by the assumption of common covariances in the classes within multivariate environment space. Maximum likelihood classification is one of a variety of alternative methods that do not have this constraint, and produce a better prediction, particularly when a priori probabilities of presence and absence are taken into account. The best predictions are obtained when the habitat is subdivided, prior to classification, on the basis of a bimodality detected on the third component axis of a principal component analysis. The results of the predictions were good, particularly for G.m.centralis and G.m.morsitans, which gave overall correct predictions of 92.8% and 85.1%, with a Kappa index of agreement between the prediction and the training data of 0.7305 and 0.641 respectively. For G.pallidipes, 91.7% of predictions were correct but the value of Kappa was only 0.549. Very clear differences are demonstrated between the habitats of the two subspecies G.m.centralis and G.m.morsitans.

Airborne-mercury detection by resonant UV laser pumping

Optical pumping of the Hg(0) (6s (1)S(0) --> 6p (3)P(1)) transition at 253.7 nm (in air) leads to extremely fast energy transfer and strong laser-induced-fluorescence (LIF) from the Hg(0) (7s(3)S(1) --> 6p (3)P(2)) green transition at 546.2 nm, which is not directly populated by the laser. Ionization occurs simultaneously and becomes particularly strong at reduced background pressures. These observations are consistent with the existence of a multiphoton process followed by electron collisional excitation. Preliminary studies are made to evaluate these phenomena for detecting elemental airborne mercury by LIF and point monitoring with an ionization detector. Measured sensitivities of 2 and 10 parts in 10(9) (ppb), respectively, at 0.1-Torr air pressure are projected to increase to 1 x 10(-4) and 1 x 10(-5) ppb after relevant system optimization.

Neuropsychological, olfactory, and hygiene deficits in men with negative symptom schizophrenia

Associations between symptom subtypes, life skills, olfactory identification, and neuropsychological ability were investigated in patients with schizophrenia and related to observations of poor personal hygiene and implied functional compromise of orbitofrontal integrity. Twenty-seven men with chronic schizophrenia were assessed using the Positive and Negative Syndrome Scale for Schizophrenia and the Life Skills Profile. Performance on the University of Pennsylvania Smell Identification Test (UPSIT), the Modified Wisconsin Card Sorting Test (MWCST), delayed response/alternation, and memory tasks derived from the Wechsler Memory Scale-Revised (WMS-R) was also compared to that of an age-, sex-, and IQ-matched control group. Patient UPSIT, MWCST, and WMS-R performance was significantly impaired in comparison to controls. Poor UPSIT performance and poor self-care were significantly associated with negative symptoms. Also, UPSIT ability was associated with performance on the MWCST in both patients and controls, whereas an association with performance on the WMS-R was only found in normal subjects rather than in the patients with schizophrenia. The importance of these findings to postulated mechanisms involving prefrontal rather than mediotemporal lobe (MTL) function in schizophrenia are discussed, as is the relevance of the use of smell identification ability to subtype identification and rehabilitative strategies.

Comparative pathogenesis of human WA1 and Babesia microti isolates in a Syrian hamster model

The pathogenesis of a newly recognized, molecularly and antigenically distinct human babesial isolate (WA1) and Babesia microti, the common cause of human babesiosis in the United States, were compared in a Syrian hamster model. A group of 33 adult female hamsters were inoculated intraperitoneally with either WA1-infected, B. microti-infected, or uninfected hamster erythrocytes. All WA1-infected animals became parasitemic by postinoculation (PI) day 3 or 4 and were severely lethargic and dyspneic by PI days 6 to 10. Death often occurred spontaneously by PI day 10, with parasitemia of 12 to 90%. Hamsters inoculated with B. microti became parasitemic by PI day 7 and developed peak parasitemia (42 to 60%) by PI day 14 that subsequently decreased to low or undetectable values. Although the B. microti-infected hamsters developed severe anemia, they generally remained asymptomatic. Postmortem examination of WA1-infected hamsters revealed intravascular aggregates of large mononuclear inflammatory cells that occasionally occluded small to medium veins, pulmonary leukoclastic phlebitis, thrombosis, and multifocal coagulative necrosis in the heart, spleen, lung, and liver. No vascular lesions or areas of coagulative necrosis were detected in any B. microti-infected or control hamsters. The results of this study suggest that marked leukocytosis followed by acute necrotizing phlebitis resulting in disseminated intravascular coagulation, thromboembolism, and infarction may be central to the pathogenesis of WA1 infections.

Challenges with Takayasu's arteritis: a case study

Takayasu's arteritis (TA) is a systemic vasculitis that involves an autoimmune-mediated transmural degeneration of the aorta and its major branches, leading to severe arterial stenoses or occlusions with subsequent cerebral, cardiopulmonary, mesenteric, renal, or limb ischemia. Patient history and physical examination, arteriography, magnetic resonance imaging, and specific laboratory tests facilitate the diagnosis of TA. Major treatments for the condition include the use of corticosteroids, cytotoxic agents, antiplatelet drugs, percutaneous transluminal angioplasty (PTA), and surgical revascularization. Major nursing interventions for TA include teaching the patient and family about the progression and treatments of TA and performing periodic patient assessments for manifestations of systemic vasculitis, alterations in tissue perfusion, and alterations in coping.

Euthanasia on trial: examining public attitudes toward non-physician-assisted death

This study investigated the influence of various contextual effects on the decisions of subjects evaluating a case of nonphysician-assisted suicide. Subjects viewed a videotaped deposition of an individual emotionally or nonemotionally describing how he assisted in the death of his terminally ill wife by disconnecting her respirator or shooting her in the head. The deposition was followed by jury instructions that outlined the duties of the subject and, in some cases, was followed by a nullification instruction that informed the subjects of their right to ignore the law in this case if they felt it would culminate in an unfair verdict. After viewing the videotape, subjects were asked to rate the guilt of the individual as well as their confidence in this rating. Results indicate that the means of death and the type of instruction significantly affect guilt ratings. The implications of these findings are discussed.

What method should be used to define 'night' when assessing diurnal systolic blood pressure variation in the elderly?

Diurnal blood pressure (BP) variation can be assessed by cusums-derived measures and by the day-night BP difference from time-, activity- and diary-defined 'night' periods. Reproducibility of diurnal systolic BP (SBP) variation by these different methods was studied in 19 active elderly normotensives, mean age 68.5 years. Subjects underwent simultaneous 24 h BP (Spacelabs 90207) and activity (Gaehwiler wrist actigraph) monitoring on two occasions (median interval 70 days). On the first occasion, mean diurnal SBP variation was 15.1 +/- 8.1 mm Hg by fixed-time definition of 'night' (22.07). When compared with 22-07 defined 'night' period, actigraph- and diary-defined 'night-time' was significantly reduced (-60 +/- 49, and -48 +/- 51 min, respectively) and consequently diurnal SBP variation was significantly greater at 18.2 +/- 8.1 mm Hg and 17.6 +/- 8.4 mm Hg, respectively. Actigraph recordings were also used to exclude 'night' BP readings associated with activity, but this did not significantly alter the diurnal SBP variation. Cusums-derived circadian alteration magnitude resulted in the greatest value for SBP variation (23.4 +/- 6.7 mm Hg). However, reproducibility of diurnal SBP variation was poor by fixed-time method with a coefficient of variation (CV) of > 50%, and only improved to 40% with diary use. Actigraph measurements, even if used to exclude BP values associated with disturbed sleep, did not improve this further. Cusums-derived measures of diurnal variation slightly improved reproducibility with a CV of 34.6% and may be a better method in the assessment of diurnal BP variation in the elderly.

Changes in the sweatspot test with ageing and relation to cardiovascular autonomic function

The sweatspot test assesses the local sweat response to an intradermal injection of acetylcholine. It has been reported as a more sensitive indicator of autonomic dysfunction in important diabetic men than either pupillary or cardiovascular tests, and has been used to establish the presence of autonomic dysfunction in patients with idiopathic chronic constipation. However, the usefulness of this test as a simple and quick method of diagnosing autonomic dysfunction in an elderly population has not been established. This is important given the high prevalence of reduced autonomic function with ageing and hypertension. We compared the age-associated responses in the sweatspot test and its relation to cardiovascular autonomic function in elderly normotensive and hypertensive subjects. We studied eleven normotensive and 24 untreated hypertensive elderly subjects (mean age 75.7 years, range 63-85) and compared the results of the sweatspot test to a young control group (n = 11, mean age 32.0 years, range 25-41), and to a standard battery of cardiovascular autonomic function tests. The median sweatspot score was significantly lower in the elderly compared with young subjects (1.9 vs. 12.0, p < 0.0001) although there was no difference between elderly normotensive and hypertensive subjects (1.6 vs. 2.4, p = 0.8). No correlation was demonstrated between the median sweatspot score and the number of abnormal cardiovascular tests. The sweatspot test was grossly abnormal in all elderly subjects and was not correlated to changes in cardiovascular autonomic function. Its diagnostic use in the elderly is therefore of very limited value.

Structure and specificity of T cell receptors expressed by potentially pathogenic anti-DNA autoantibody-inducing T cells in human lupus

The production of potentially pathogenic anti-DNA autoantibodies in SLE is driven by special, autoimmune T helper (Th) cells. Herein, we sequenced the T cell receptor (TCR) alpha and beta chain genes expressed by 42 autoimmune Th lines from lupus patients that were mostly CD4+ and represented the strongest inducers of such autoantibodies. These autoimmune TCRs displayed a recurrent motif of highly charged residues in their CDR3 loops that were contributed by N-nucleotide additions and also positioned there by the recombination process. Furthermore, Th lines from four of the five patients showed a marked increase in the usage of the V alpha 8 gene family. Several independent Th lines expressed identical TCR alpha and/or beta chain sequences indicating again antigenic selection. 10 of these Th lines could be tested further for antigenic specificity. 4 of the 10 pathogenic anti-DNA autoantibody-inducing Th lines responded to the non-histone chromosomal protein HMG and two responded to nucleosomal histone proteins; all presented by HLA-DR molecules. Another Th line responded to purified DNA more than nucleosomes. Thus, these autoimmune Th cells of lupus patients respond to charged epitopes in various DNA-binding nucleoproteins that are probably processed and presented by the anti-DNA B cells they selectively help.

In vitro and ex vivo effects of cyclosporin A on phagocytic host defenses against Aspergillus fumigatus

Because cyclosporin A (CsA) is extensively used as an immunosuppressive agent, its effects on phagocytic defenses against Aspergillus fumigatus were studied in vitro and ex vivo. After incubation with 10 to 250 ng of CsA per ml at 37 degrees C for 60 min, polymorphonuclear leukocytes (PMNs) exhibited unaltered superoxide anion (O2-) production in response to phorbol myristate acetate and N-formylmethionyl leucyl phenylalanine, whereas > or = 500 ng/ml significantly suppressed it (P < 0.01). Moreover, at < 250 ng of CsA per ml, PMNs exhibited no change in their capacity to damage unopsonized hyphae of A. fumigatus compared with controls, whereas at > or = 250 ng/ml, CsA suppressed the function (P < 0.01). Although neither CsA (250 ng/ml) nor hydrocortisone (10 micrograms/ml) suppressed PMN O2- production in response to phorbol myristate acetate and N-formylmethionyl leucyl phenylalanine, combination of the two agents reduced the function compared with that at the baseline (P < 0.05). Incubation of monocytes with 100 ng of CsA per ml for 1 or 2 days suppressed their antihyphal activity. No essential change in phagocytic activity of monocyte-derived macrophages (MDMs) against A. fumigatus conidia, tested as the percentage of phagocytosing MDMs and average number of MDM-associated conidia, was detected after 2 or 4 days of incubation with 10 to 1,000 ng of CsA per ml. Furthermore, in rabbits treated with CsA (up to 20 mg/kg of body weight per day intravenously for 7 days), neither O2- production and hyphal damage caused by PMNs or monocytes against hyphae nor phagocytosis of conidia by pulmonary alveolar macrophages was significantly suppressed. Thus, these results demonstrated that CsA within therapeutically relevant concentrations does not suppress antifungal activity of phagocytes except that of circulating monocytes. However, it may induce significant immunosuppression of phagocytes' antifungal function at relatively high concentrations in vitro, especially when combined with corticosteroids.

Orbital emphysema: how common, how significant?

STUDY OBJECTIVE

To describe the natural history of orbital emphysema and its management in the emergency setting.

DESIGN

Retrospective medical record review.

SETTING

Inner-city integrated hospital system (four divisions) including one Level I trauma center.

PARTICIPANTS

All cases of orbital floor fracture and orbital emphysema from January 1, 1988, to December 31, 1993.

RESULTS

The average patient was aged 33 years, and the male-to-female ratio was 7 to 1. Trauma was the underlying etiology in all patients. Seventy-four percent of patients required hospitalization, and 43% developed significant complications. Eighty-three percent were managed with antibiotics. Orbital emphysema was identified on conventional radiographs in 65% of cases.

CONCLUSION

Identification of orbital emphysema in the ED should prompt a careful search for associated injury. Consultation should be sought in the presence of orbital or ocular injury. Antibiotic prophylaxis is not necessary for clean wounds.

Postcopulatory, prezygotic isolation: intraspecific and interspecific sperm precedence in Tribolium spp., flour beetles

We investigated intraspecific and interspecific patterns of paternity in Tribolium castaneum, the flour beetle, by mating females either to pairs of conspecific males or to one conspecific and one heterospecific male of the closely related species, T. freemani. Females of both species store sperm in the spermatheca after copulation and postcopulatory, prezygotic reproductive isolation has been reported between this pair of species. When conspecific males of contrasting genotype are mated simultaneously to T. castaneum females, we observed extremely high levels of variation among females in the pattern of sperm precedence as shown by the offspring genotypes. In contrast, T. castaneum females mated simultaneously to a conspecific and a heterospecific male produced over 99 per cent conspecific progeny. When conspecific males were mated sequentially to T. castaneum females, within 3-7 days, all offspring were sired by the second male. In contrast, when a conspecific male was replaced with a T. freemani male, most females continued to produce only first-male, conspecific offspring for the next 10 days. When a heterospecific male was replaced with a conspecific male, T. castaneum females changed from producing hybrid to conspecific offspring within 3 days. We discuss the evolutionary implications of these findings.

The acute effects of a single dopamine infusion in elderly patients with congestive cardiac failure

1. Dopamine (DA) at low doses (2.5 micrograms kg-1 min-1) produces a measurable increase in glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) in young healthy subjects and has a therapeutic effect in younger patients with congestive cardiac failure (CCF). In elderly healthy subjects, DA increases ERPF but does not increase GFR in all subjects. 2. To determine the potential therapeutic use of DA in elderly subjects with CCF, we studied 17 patients (5 male) aged 79.9 years (range 68 to 93 years) admitted to hospital for inpatient treatment of CCF resistant to diuretic and angiotensin converting enzyme inhibitor therapy. The effects of a single infusion DA at 2.5 micrograms kg-1 min-1 on GFR and ERPF were assessed in a double-blind, placebo controlled prospective study. 3. There were no significant differences in GFR or ERPF between control and DA. A reduction in GFR was seen in some patients. 4. DA at low dosage was not shown to benefit elderly patients with resistant CCF, and in some patients was detrimental. Higher doses or a combination with other inotropes may be necessary for a renal effect in elderly patients.

Body smuggling of illicit drugs: two cases requiring surgical intervention

The smuggling of illicit drugs by concealing them within the human body has become a widespread practice. Those individuals who transport packaged drugs are commonly known as "body packers" or "mules". "Body stuffers," on the other hand, are individuals who emergently place the contraband in a body orifice when they sense apprehension is imminent. In the latter instance, the drugs are not well packaged for transportation by human "consumption," hence the high risk for leakage. These individuals require prompt surgical attention under two circumstances: when they are found to suffer from drug overdosage caused by inadvertent leakage or when obstruction in the body is caused by the drug-laden bags. Two such cases are reported. The first patient presented with acute drug overdose and required an emergency laparotomy. The second patient presented with pyloric obstruction and was treated by endoscopic removal of the bag. One must be aware that these patients are walking time bombs, carrying drugs that may be well packed but have the potential to deliver a lethal dose without warning. Knowledge of the type of drug and type of packaging are essential in managing these patients. The overall plan should be close observation, careful monitoring, conservative therapy, and expectant rapid surgical intervention as needed.

Self-mutilation: three cases and a review of the literature

The self-mutilating patient is an unusual psychiatric presentation in the emergency department (ED). Nonetheless, serious underlying psychiatric pathology and drug abuse are important background risk factors. A careful stepwise approach in the ED is essential, although the prognosis, follow-up, and eventual rehabilitation are poor.

Vaginal bleeding secondary to an aborting uterine leiomyoma

The authors present the case of a young woman who presented to the emergency department with vaginal bleeding and an "aborting" uterine leiomyoma. Although well described in the gynecologic literature, this phenomenon is not commonly seen in the emergency department, nor is it well described in the emergency medicine literature. The case highlights the importance of a thorough pelvic examination in all women presenting with a complaint of vaginal bleeding, and in addition it describes an atypical presentation for uterine leiomyomas.

Dynamic and steady-state ventilatory and gas exchange responses to arm exercise

Previous studies have suggested that, for the same power output, arm exercise requires higher oxygen uptake (VO2), carbon dioxide output (VCO2), and ventilation (VE) than leg exercise and that response kinetics are slower. To evaluate these differences, four healthy subjects performed a total of 95 arm cranking tests. Each subject performed several tests at each of three or four power outputs spaced evenly below the maximum the subject could sustain (average = 53 W). Breath-by-breath responses to identical stimuli were averaged. End-exercise blood lactate was determined at each power output. Responses were compared to leg exercise responses in these subjects (J. Appl. Physiol. 67:547-555, 1989). For power outputs unassociated with lactic acidosis, differences between steady-state VO2, VCO2, and VE responses for arm and leg exercise were not significant. At higher power outputs, the higher VO2, VCO2, and VE during arm exercise were well correlated with higher lactate. For power outputs not engendering lactic acidosis, the time constants (tau) for VO2, VCO2 and VE were not greatly different for arm than for leg exercise. For each variable, at higher power outputs tau became longer by an amount correlated with higher lactate level. Like leg exercise, the slower kinetics of VO2 and VE (but not VCO2) at higher power outputs were well described as a superimposed slower component. We conclude that both dynamic and steady-state responses of VE and gas exchange to arm exercise do not differ substantially from those to leg exercise so long as the power output does not elevate blood lactate.

Factor VIIa/tissue factor-catalyzed activation of factors IX and X on a cell surface and in suspension: a kinetic study

The kinetics of activation of factor IX and factor X by factor VIIa was studied in the presence of various sources of tissue factor: (1) a surface membrane of human ovarian carcinoma cell line, OC-2008 (2) the cell lysate (of OC-2008) and (3) reconstituted purified human tissue factor. The rates of activation of factors IX and X were monitored in activation peptide release assays using tritiated substrates. The results indicate that the apparent Km values for factor IX and factor X were similar for a given tissue factor, but varied with tissue factor source. The source of tissue factor greatly influenced the apparent differences in Vmax for factors IX and X. When a surface of monolayer provided tissue factor, the Vmax of factor IX was only 2-3 fold lower than factor X, but when either a cell lysate or purified tissue factor was the source of cofactor activity, the difference in Vmax rose to about 8-10 fold. Although, the tissue factor apoprotein in the cells was expressed entirely on the outer surface membrane, the activity of tissue factor on the intact cell surface was 50 to 100-fold lower than in the lysed cell preparation.

Suicide policies in secure environments

A cohort of nurses and prison officers working in regional secure units, special hospitals and prisons were surveyed to establish their attitudes about observation policies designed to prevent patients/inmates from committing suicide. The results suggest that policies are rarely, if ever, reviewed, although there appear to be differences of emphasis in the three environments. Recommendations of the study include the need for improved staff communication, regular review of policies and better preparation of personnel.

The formation of 3 alpha- and 3 beta-acetoxytropanes by Datura stramonium transformed root cultures involves two acetyl-CoA-dependent acyltransferases

Tropine (tropan-3 alpha-ol) is an intermediate in the formation of hyoscyamine. An acyltransferase activity that can acetylate tropine using acetylcoenzyme A as cosubstrate has been found in transformed root cultures of Datura stramonium. A further acyltransferase activity that acetylates pseudotropine (tropan-3 beta-ol) with acetyl-coenzyme A is also present. These two activities can be partially resolved by anion-exchange chromatography, some fractions containing only the pseudotropine-utilizing activity. The basic properties of these two enzymes are reported and their roles in forming the observed alkaloid spectrum of D. stramonium roots discussed.

Influence of work rate on ventilatory and gas exchange kinetics

A linear system has the property that the kinetics of response do not depend on the stimulus amplitude. We sought to determine whether the responses of O2 uptake (VO2), CO2 output (VCO2), and ventilation (VE) in the transition between loadless pedaling and higher work rates are linear in this respect. Four healthy subjects performed a total of 158 cycle ergometer tests in which 10 min of exercise followed unloaded pedaling. Each subject performed three to nine tests at each of seven work rates, spaced evenly below the maximum the subject could sustain. VO2, VCO2, and VE were measured breath by breath, and studies at the same work rate were time aligned and averaged. Computerized nonlinear regression techniques were used to fit a single exponential and two more complex expressions to each response time course. End-exercise blood lactate was determined at each work rate. Both VE and VO2 kinetics were markedly slower at work rates associated with sustained blood lactate elevations. A tendency was also detected for VO2 (but not VE) kinetics to be slower as work rate increased for exercise intensities not associated with lactic acidosis (P less than 0.01). VO2 kinetics at high work rates were well characterized by the addition of a slower exponential component to the faster component, which was seen at lower work rates. In contrast, VCO2 kinetics did not slow at the higher exercise intensities; this may be the result of the coincident influence of several sources of CO2 related to lactic acidosis. These findings provide guidance for interpretation of ventilatory and gas exchange kinetics.