Ecotoxicity hazard assessment of styrene

The ecotoxicity of styrene was evaluated in acute toxicity studies of fathead minnows (Pimephales promelas), daphnids (Daphnia magna), amphipods (Hyalella azteca), and freshwater green algae (Selenastrum capricornutum), and a subacute toxicity study of earthworms (Eisenia fostida). Stable exposure levels were maintained in the studies with fathead minnows, daphnids, and amphipods using sealed, flowthrough, serial dilution systems and test vessels. The algae were evaluated in a sealed, static system. The earthworms were exposed in artificial soil which was renewed after 7 days. Styrene concentrations in water and soil were analyzed by gas chromatography with flame ionization detection following extraction into hexane. Test results are based on measured concentrations. Styrene was moderately toxic to fathead minnows, daphnids, and amphipods: fathead minnow: LC50 (96 hr), 10 mg/liter, and NOEC, 4.0 mg/liter; daphnids: EC50 (48 hr), 4.7 mg/liter, and NOEC, 1.9 mg/liter; amphipods: LC50 (96 hr), 9.5 mg/liter, and NOEC, 4.1 mg/liter. Styrene was highly toxic to green algae: EC50 (96 hr), 0.72 mg/liter, and NOEC, 0.063 mg/liter; these effects were found to be algistatic rather than algicidal. Styrene was slightly toxic to earthworms: LC50 (14 days), 120 mg/kg, and NOEC, 44 mg/kg. There was no indication of a concern for chronic toxicity based on these studies. Styrene's potential impact on aquatic and soil environments is significantly mitigated by its volatility and biodegradability.

Assessing the future

Awareness of the importance of wound assessment and management appears to be increasing, and centres of excellence are emerging. Nurses have a responsibility to provide effective research-based care for patients, but require knowledge and training to do this. Research-based practice is important, but there is a case for more nurses being involved in research in this area. Nurses realise that, where disagreement in wound management arises between themselves and other professions, one way to overcome this is by demonstrating that they are skilled, proficient and knowledgeable practitioners in wound care. In this way, autonomy may be promoted and nurses can continue to push forward the boundaries of wound management, questioning rituals and promoting innovation. Good documentation is also important and the use of a wound assessment tool may assist in this. The challenge now is for nurses to demand adequate training in order to help them become the skilled, proficient and knowledgeable practitioners they strive to be.

The cost and benefit of prophylaxis against deep vein thrombosis in elective hip replacement. DVT/PE Prophylaxis Consensus Forum

A consensus forum was convened to evaluate the economic considerations associated with prophylaxis against thrombo-embolic disease in patients undergoing hip replacement therapy in South Africa. This forum consists of orthopaedic surgeons, vascular surgeons and a statistician.

METHODS

The forum was instructed to evaluate the economic costs of the commonly used forms of prophylaxis of thrombo-embolism in patients undergoing hip replacement surgery in South Africa, looking at short-term events only. The methods used for the prophylaxis of thrombo-embolism in South Africa were determined by a postal survey. A decision tree was constructed to determine the events that will occur after a clinical decision to use no prophylaxis. The probabilities of these events were then determined. Protocols for and costs of prophylaxis and treatment were established. With the decision tree and these costs, the cost of the various modalities of prophylaxis was then determined.

RESULTS

The probability, determined by the forum, of developing a deep-vein thrombosis (DVT) when no prophylaxis is used was 0.5, with a mortality rate of 2.1%. The cost of this decision was R875. No prophylaxis given, but a venogram performed on day 7, reduced the mortality rate to 0.7%; however, this cost R3 017. The cost of low-molecular-weight heparin was R1 223 (probability 0.26, mortality rate 1.1%), while unfractionated heparin with a graduated compression stocking (GCS) cost R1 351 (probability 0.24, mortality rate 1%). Aspirin with a GCS cost R777 (probability 0.35, mortality rate 1.5%).

Characterization of methemoglobin formation induced by 3,5-dichloroaniline, 4-amino-2,6-dichlorophenol and 3,5-dichlorophenylhydroxylamine

3,5-Dichloroaniline is an intermediate in the production of certain fungicides. This study characterized the capacity of 3,5-dichloroaniline and two putative metabolites to induce methemoglobin formation. In vivo intraperitoneal (i.p.) administration of 0.8 mmol/kg 3,5-dichloroaniline resulted in elevated (P < 0.05) methemoglobin levels at 2 and 4 h after injection and returned to control values within 8 h. In vitro methemoglobin generation was monitored in washed erythrocytes incubated for 60 min at 37 degrees C with 4 and 8 mM 3,5-dichloroaniline. Methemoglobin generation in vitro was higher (P < 0.05) than control values in erythrocytes incubated for 30 min with 0.2-0.6 mM 4-amino-2,6-dichlorophenol or 5-100 microM 3,5-dichlorophenylhydroxylamine. The in vitro methemoglobin generating capacity in decreasing order was: 3,5-dichlorophenylhydroxylamine > 4-amino-2,6-dichlorophenol > > 3,5-dichloroaniline. The results of the in vitro studies further indicated that none of the compounds tested induced lipid peroxidation. Erythrocytes incubated with 5-100 microM 3,5-dichlorophenylhydroxylamine in vitro were associated with depletion of glutathione. These results indicated that: (a) 3,5-dichloroaniline and its metabolites can induce methemoglobin formation; (b) the N-hydroxy metabolite was the most potent inducer of hemoglobin oxidation and (c) glutathione depletion was associated with methemoglobin formation by 3,5-dichlorophenylhydroxylamine.

An evaluation of initiatives to improve family planning use by African-American adolescents

Teen pregnancies in the United States have reached epidemic proportions, and consequently, efforts to promote family planning among adolescents have increased. At the Orleans Parish Family Planning Clinic in New Orleans, Louisiana, adolescent-specific initiatives were implemented to improve understanding of family planning services and promote contraceptive use. Since 92% of the patients are African American, the study population was limited to this group. This study examines the efficacy of two initiatives (i.e., orientation sessions and 3-month booster visits conducted in adolescent-specific clinics) for improving initiation and continuation of family planning services among African-American adolescent women. Initiation of services was compared among those who attended the orientation session and those who did not attend. Continuation of services was determined by attendance of the annual visit for those who attended the 3-month follow-up visit and those who did not attend. Of 737 teens entering into the clinic, the mean age was 16 years, 95% were enrolled in school, 23% attended the orientation session, and 71% initiated services. Of the 507 who initiated services and who underwent follow-up for at least 12 months, 29% attended the 3-month follow-up visit and 32% attended an annual visit. Attendance of the orientation session was associated with initiation of services and attendance of the 3-month booster visits was associated with attendance of the annual visit in multivariate logistic regression. Simple and cost-effective techniques such as orientation sessions and follow-up visits conducted in adolescent clinics can improve initiation of family planning and compliance among adolescents.

The role of surgical ligation of patent ductus arteriosus in the era of the Rashkind device

BACKGROUND

The role of surgery in managing patent ductus arteriosus (PDA) was studied in the era of the Rashkind double-umbrella device.

METHODS

All 354 patients with PDA referred to our center in a 5-year period were included in this report. Of the 354 patients, 236 underwent cardiac catheterization with the intent of transcatheter PDA closure, and 118 had surgical intervention.

RESULTS

In 46 (19.5%) of the 236 patients having cardiac catheterization, the procedure either was abandoned or failed. Color Doppler echocardiography demonstrated total occlusion of the ductus after 24 hours in 97 patients (41%) in the cardiac catheterization group. An additional 20 patients had no residual leaks at follow-up. Twenty other patients underwent reocclusion because of a residual shunt. Thus, of the 236 patients, 137 (58%) had successful complete closure of the PDA. Surgical PDA ligation was performed in 118 patients as the initial procedure and in 26 of the 46 patients in whom transcatheter closure was abandoned. If the remaining 20 patients in whom transcatheter closure failed are added to the 144 patients who underwent PDA ligation, the percentage having surgical intervention versus transcatheter occlusion is higher than 46%.

CONCLUSIONS

Our data suggest that surgery plays a major role in the management of patients with PDA despite the advent of new interventional catheterization techniques.

Active site mutants implicate key residues for control of color and light cycle kinetics of photoactive yellow protein

To understand how the protein and chromophore components of a light-sensing protein interact to create a light cycle, we performed time-resolved spectroscopy on site-directed mutants of photoactive yellow protein (PYP). Recently determined crystallographic structures of PYP in the ground and colorless I2 states allowed us to design mutants and to study their photosensing properties at the atomic level. We developed a system for rapid mutagenesis and heterologous bacterial expression for PYP apoprotein and generated holoprotein through formation of a covalent thioester linkage with the p-hydroxycinnamic acid chromophore as found in the native protein. Glu46, replaced by Gln, is buried in the active site and hydrogen bonds to the chromophore's phenolate oxygen in the ground state. The Glu46Gln mutation shifted the ground state absorption maximum from 446 to 462 nm, indicating that the color of PYP can be fine-tuned by the alteration of hydrogen bonds. Arg52, which separates the active site from solvent in the ground state, was substituted by Ala. The smaller red shift (to 452 nm) of the Arg52Ala mutant suggests that electrostatic interactions with Arg52 are not important for charge stabilization on the chromophore. Both mutations cause interesting changes in light cycle kinetics. The most dramatic effect is a 700-fold increase in the rate of recovery to the ground state of Glu46Gln PYP in response to a change in pH from pH 5 to 10 (pKa = 8). Prompted by this large effect, we conducted a careful reexamination of pH effects on the wild-type PYP light cycle. The rate of color loss decreased about 3-fold with increasing pH from pH 5 to 10. The rate of recovery to the colored ground state showed a bell-shaped pH dependence, controlled by two pKa values (6.4 and 9.4). The maximum recovery rate at pH 7.9 is about 16 times faster than at pH 5. The effect of pH on Arg52Ala is like that on wild type except for faster loss of color and slower recovery. These kinetic effects of the mutations and the changes with pH demonstrate that both phases in PYP's light cycle are actively controlled by the protein component.

Problems found in the over-75s by the annual health check

BACKGROUND

Research into the health of elderly people has found problems unknown to their general practitioners. It was anticipated that annual checks, as required by the 1990 general practitioner contract, would help to detect these problems, yet the value of these checks has been questioned.

AIM

To investigate the problems found by general practice contractual annual checks of the over-75s and the consequent actions taken; to identify patient, demographic or practice characteristics associated with the discovery of problems.

METHOD

In 40 practices, information was collected on patients over 75 years of age receiving a health check during a 3-month period. Practices used their normal methods of recruitment and assessment. Practice staff were interviewed to find how assessments were organized.

RESULTS

Practices saw a mean of 12% of their over-75s during the study; 44% were found to have at least one problem. Action was taken to help resolve problems in 82% of patients with a problem. The most prevalent problems related to physical condition, and fewer functional problems than expected were found. There were large differences between practices in the proportions of elderly patients seen for a check and the proportion found to have problems; these were not attributable to practice size or demography. Multivariate analysis showed that practice or patient characteristics were poor predictors of finding problems.

CONCLUSION

The argument in favour of conducting annual checks is supported by the finding that nearly half the patients assessed were found to have problems for which some action was taken. Some practices could increase their rate of uptake by modifying the organization of invitations for checks. More problems may be found by adopting a more functionally based assessment.

Clinical and laboratory features of adult T-cell leukaemia lymphoma in Barbados

We describe the clinical and pathological features of 23 Afro-Caribbean patients with adult T-cell leukaemia/lymphoma admitted to the Queen Elizabeth Hospital, Barbados over a 5 year period. There were 9 males and 14 females, with a median age of 38 years (range 14-84). Twelve had acute leukaemia, 10 lymphoma (including 4 with solitary extra nodal lesions) and 1 smouldering subtype. Two patients had a past history of tropical spastic paraparesis/HTLV I associated myelopathy (TSP/HAM). The prognosis was poor, with only 3 complete responses to chemotherapy (CHOP) lasting from 9 to 36 months. We conclude that ATLL in Barbados is similar to the disease in the other Caribbean islands and Japan, except that in Barbados the age of onset is over a decade younger than in Japan.

Arthrogryposis multiplex congenita in a monozygotic twin. An intrauterine lesion?

Arthrogryposis multiplex congenita is a specific, well-defined congenital deformity which primarily affects muscles of limbs resulting in secondary joint deformities. The aetiology is still uncertain. One of monozygotic twin brothers with classical arthrogryposis multiplex congenita is presented, proving that this specific condition is not genetically transmitted.

Differential patterns of serum biomarkers of immune activation in human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis, and adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATL) and human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) are associated with differing patterns of immune dysfunction. Biomarkers of immune activation may correlate with perturbations of immune function associated with these diseases. We conducted a pilot cross-sectional study to assess four candidate biomarkers of immune activation. beta 2-microglobulin, neopterin, tryptophan, and kynurenine levels were assayed in stored sera from asymptomatic, human T-cell leukemia virus type I (HTL V-I)-seronegative (HTLV-I-) and HTLV-I-seropositive (HTLV-I+) individuals, and ATL and HAM/TSP patients previously enrolled in seroepidemiological studies in Jamaica. Mean levels of beta 2-microglobulin, neopterin, and kynurenine were significantly elevated among ATL patients compared to the other study groups. Mean tryptophan levels were significantly lower among ATL and HAM/TSP patients than HTLV-I- and HTLV-I+ groups. No significant differences in biomarkers were found between the HTLV-I- and HTLV-I+ groups. Among HAM/TSP patients, a significant association was found between elevated neopterin levels and symptoms of less than 4 years duration. In Cox proportional hazards regression modeling, neopterin and tryptophan were found to be independent predictors of survival among ATL patients. This study demonstrates a differential pattern of biomarkers of immune activation among ATL and HAM/TSP patients compared to HTLV-I- and HTLV-I+ individuals. Neopterin and tryptophan may be useful clinical indicators of disease severity and prognosis among HAM/TSP and ATL patients.

The complications of lung resection in adults: acute respiratory distress syndrome (ARDS)

Postoperative lung injury is a recognized complication of pulmonary resection. In adults, this is manifest in its most severe form as the acute respiratory distress syndrome (ARDS). ARDS is characterized by high permeability pulmonary oedema resulting in refractory and often terminal hypoxaemia. Few data exist regarding the prevalence of lung injury following lung resection. Most recent series suggest that around 5% of patients develop some degree of lung injury. Those that develop frank ARDS have a poor prognosis compared to those who suffer lesser degrees of damage. The pathogenesis of lung injury in these circumstances remains unknown. Perioperative fluid overload, increased blood flow through the remaining lung postoperatively, reoxygenation injury and activation of inflammatory mediators have been postulated as possible causes. Conventional parameters for preoperative assessment do not predict those patients most likely to develop lung injury in these circumstances. Clinical management strategies for acute respiratory distress syndrome complicating lung resection are discussed.

Seasonal-, tidal-cycle- and microhabitat-related variation in membrane order of phospholipid vesicles from gills of the intertidal mussel Mytilus californianus

Alterations in the order, or fluidity, of cellular membranes in response to variations in environmental temperature are well known. The mussel Mytilus californianus, a common inhabitant of mid-intertidal regions along the Pacific coast of North America, can experience large (20 &deg;C or more) and cyclic (every 6 h) changes in body temperature (Tb ) during tidal cycles. In the present study, we explore membrane order during seasonal and tidal temperature cycles and find that vesicles prepared from gill phospholipids exhibit significant seasonal differences in order that are consistent with homeoviscous adaptation and suggest winter-acclimatization to mean Tb values and summer-acclimatization to upper extreme Tb values or to large cyclic thermal fluctuations, despite repeated resubmergence in sea water at 10 &deg;C during both seasons. Phospholipid vesicles prepared from the gills of mussels acclimated for 6 weeks to constant high or low temperatures in the laboratory fail to exhibit temperature-compensatory differences in order. In addition, during the summer, mussels inhabiting high intertidal sites, but not those from low sites, possess the ability to alter membrane order rapidly (within hours). This alteration of order appears to represent a mechanism designed to offset the thermal variations encountered during the tidal cycle. Thus, M. californianus have the ability to adjust membrane order on seasonal as well as hourly time scales and do so on the basis of their height in the intertidal region.

Mammary hamartoma--an under-recognised breast lesion

The clinical, histological and immunohistochemical features of the first three cases of mammary hamartoma diagnosed at the University Hospital of the West Indies are reported. These tumours are innocuous and under-recognized although the mammographic features are characteristic. With increased utilization of this test in breast cancer detection in our region, it is likely that more of these lesions will be identified.

Hyperactivity and delay aversion. III: The effect on cognitive style of imposing delay after errors

The claim that impulsiveness associated with hyperactivity is the result of deficits in inhibition of responses over time was examined. The cognitive style of hyperactive children was studied under two conditions. As in previous studies hyperactive children appeared impulsive (i.e. gave shorter latencies and made more errors than controls) under conditions where this style led to shorter trials. In contrast, in a revised condition where each error led to an enforced/fixed trial length, hyperactive children waited as long as controls before responding, but still made more errors. Hyperactive children withheld responses when this offered them the best chance of avoiding extra delay. They were however, unable to use the extra time provided as effectively as controls. The link between hyperactive children's aversion to delay and their poor use of time is discussed.