Raised dietary n-6 polyunsaturated fatty acid intake increases 2-series prostaglandin production during labour in the ewe

Preterm labour is the major cause of perinatal morbidity and mortality in humans. The incidence is around 10% and the causes are often unknown. Consumption of dietary n-6 polyunsaturated fatty acids (PUFAs) in western societies is increasing. These are metabolized to arachidonic acid, the precursor for 2-series prostaglandins (PGs), major signalling molecules during labour. This study investigated the effect of dietary supplementation with linoleic acid (LA, 18: 2, n-6) on parturition. Ewes were fed a control or LA-supplemented diet from 100 days gestation. Labour was induced using a standardized glucocorticoid challenge (dexamethasone, Dex) to the fetus, starting on day 139. Electromyographic (EMG) activity and fetal and maternal circulating PG concentrations were monitored. One third of LA-fed ewes delivered early (pre-Dex) although basal uterine EMG activity preceding Dex was higher in control ewes (P < 0.05). A steep increase in EMG activity occurred 18-38 h after the start of Dex infusion. Twice basal EMG activity (defined as established labour) occurred on average 7 h earlier in the LA-supplemented ewes (P < 0.05). The basal concentrations of maternal and fetal PGFM and fetal PGE(2) were approximately doubled in LA-supplemented ewes before the start of Dex infusion (P < 0.01). The rise in fetal PGE(2) and maternal oestradiol concentrations post-Dex occurred earlier in the LA-supplemented ewes. All PG measurements remained significantly higher in the LA-supplemented ewes during labour onset. This study suggests that consumption of a high LA diet in late pregnancy can enhance placental PG production and may thus increase the risk of preterm labour.

Historical and other patterns of monomethyl and inorganic mercury in the Florida panther (Puma concolor coryi)

Since the late 1980s, elevated levels of mercury have been reported in the tissues of the Florida panther (Puma concolor coryi) from the Florida Everglades. The extent, degree, and length of time of mercury contamination in the Florida panther are unknown. The objective of this study was to determine the historical and other patterns of monomethyl and inorganic mercury in the Florida panther by analysis of mercury in panther hair from museum collections. In addition, this study evaluated the effects of preservation of skins on mercury concentrations in hair and the representativeness of museum collections for evaluating historical trends of contamination in the Florida panther. Hair from 42 Florida panther specimens collected from 1896 to 1995 was analyzed for both monomethyl and inorganic mercury. Monomethyl mercury (MMHg) and inorganic mercury (IHg) were found in all specimens. Monomethyl mercury in hair from untanned skins was significantly higher than MMHg in hair from tanned skins. For untanned specimens, the mean MMHg concentration in hair was 1.62 +/- 1.87 mug/g (range 0.11 to 6.68 mug/g, n = 16). Monomethyl mercury accounted for 88% of the total mercury in untanned Florida panther hair. No sexual or geographical differences were found. Although MMHg is generally stable in hair, the tanning process appears to reduce the amount of MMHg in hair. In addition, exogenous IHg contamination of the panther hair was found in museum specimens, especially in older specimens. The implication of these and other factors in interpreting results of museum studies is discussed. The presence of MMHg in panther hair since the 1890s indicates long-term and widespread exposure of the Florida panther to mercury. Levels of MMHg are significantly greater in the 1990s than the 1890s. When combined with field studies of mercury in the Florida panther, considerable individual variability is observed, reflecting short-term changes in exposure of individual panthers to mercury. Although museum specimens showed a significant increase in MMHg over the last 100 years, they did not show the magnitude of increase that field populations of Florida panthers did. A number of Florida panthers appeared to be at risk from mercury over their lifetimes, especially individuals from the early 1990s.

Mono and diterpene production inEscherichia coli

Mono- and diterpenoids are of great industrial and medical value as specialty chemicals and pharmaceuticals. Production of these compounds in microbial hosts, such as Escherichia coli, can be limited by intracellular levels of the polyprenyl diphosphate precursors, geranyl diphosphate (GPP), and geranylgeranyl diphosphate (GGPP). To alleviate this limitation, we constructed synthetic operons that express three key enzymes for biosynthesis of these precursors: (1). DXS,1-deoxy-d-xylulose-5-phosphate synthase; (2). IPPHp, IPP isomerase from Haematococcus pluvialis; and (3). one of two variants of IspA, FPP synthase that produces either GPP or GGPP. The reporter plasmids pAC-LYC and pACYC-IB, which encode enzymes that convert either FPP or GGPP, respectively, to the pigment lycopene, were used to demonstrate that at full induction, the operon encoding the wild-type FPP synthase and mutant GGPP synthase produced similar levels of lycopene. To synthesize di- or monoterpenes in E. coli using the GGPP and GPP encoding operons either a diterpene cyclase [casbene cyclase (Ricinus communis L) and ent-kaurene cyclase (Phaeosphaeria sp. L487)] or a monoterpene cyclase [3-carene cyclase (Picea abies)] was coexpressed with their respective precursor production operon. Analysis of culture extracts or headspace by gas chromatography-mass spectrometry confirmed the in vivo production of the diterpenes casbene, kaur-15-ene, and kaur-16-ene and the monoterpenes alpha-pinene, myrcene, sabinene, 3-carene, alpha-terpinene, limonene, beta-phellandrene, alpha-terpinene, and terpinolene. Construction and functional expression of GGPP and GPP operons provides an in vivo precursor platform host for the future engineering of di- and monoterpene cyclases and the overproduction of terpenes in bacteria.

Outcome of three consecutive inadequate cervical smears

A retrospective audit of women with three consecutive inadequate cervical smears during 1998-99 was conducted at Birmingham Heartlands Hospital. The commonest reasons were obscured by polymorphs (34.5%) and sparse cellularity (28.9%). Seventy-three per cent (73%) were followed up at colposcopy and 22.1% had histological assessment; 15.9% of women had an abnormality detected, 10.6% with abnormal histology and 5.3% with a cytological abnormality only. Cytological abnormalities were seen in 11.1% of the screening population. This study did not identify a cytological criterion to differentiate those that would or would not have an abnormality on follow-up. It is suggested that all women with three consecutive inadequate smears should have adequate follow-up, although this may place increased demands on colposcopy services.

A phase II study to evaluate the efficacy of dexmedetomidine for sedation in the medical intensive care unit

OBJECTIVE

To evaluate dexmedetomidine for sedation of patients in the medical ICU.

DESIGN AND SETTING

Prospective observational study in an intensive care unit of a university hospital. PATIENTS. Twelve ventilated patients with median APACHE II score 23 (range 10-26).

INTERVENTIONS

Patients received a loading dexmedetomidine infusion of 1 microg x kg(-1) over 10 min followed by a maintenance infusion rate of 0.2-0.7 microg x kg(-1) x h(-1) for up to 7 days. After experience with the first four patients this maintenance rate of infusion was increased to a maximum of 2.5 microg kg(-1) x h(-1). If required, propofol and morphine provided rescue sedation and analgesia, respectively.

RESULTS

The first four patients with dexmedetomidine infusion at 0.7 microg x kg(-1) x h(-1)all required rescue sedation with a propofol infusion. A protocol amendment allowed the next eight patients to receive higher dexmedetomidine infusions (mean 1.0+/- microg x kg(-1) x h(-1)). Five of the next eight patients did not required propofol, and two patients only required minimal propofol infusions (20-40 mg x h(-1)). A further patient, with hepatic encephalopathy, required a propofol at 50-100 mg x h(-1). Only modest falls in arterial pressure, heart rate and cardiac output were seen, and no rebound sequelae occurred on discontinuation of dexmedetomidine. Adverse cardiovascular events were nearly all confined to the initial loading dose period of dexmedetomidine.

CONCLUSIONS

Sedation with dexmedetomidine is efficacious in critically ill medical patients requiring mechanical ventilation in the intensive care unit. A reduction in loading infusion is advised, but higher maintenance infusions may be required to that seen previously in the postoperative ICU patient.

A primary tumour of the oesophagus with both melanocytic and schwannian differentiation. Melanocytic schwannoma or malignant melanoma?

A 76 year old white woman presented with a four month history of dysphagia and weight loss. Clinical, radiological, and endoscopic examination revealed a pigmented mass in the lower third of the oesophagus. The preoperative diagnosis, including biopsy examination, was that of malignant melanoma. Following oesophageal resection, the mass was found to be a localised, relatively superficial tumour with light, electron microscopic, and immunohistochemical features common to both Schwann cells and melanocytes. The patient survived 46 months after surgery and died of a stroke, with no evidence of tumour recurrence. The tumour is presented as a case of melanocytic schwannoma, with unique features when compared with oesophageal melanotic schwannomas and malignant melanomas described in the literature. The differential diagnosis is discussed and an origin from a common precursor cell of neural crest origin is postulated.

Study of Medicare beneficiary complaint procedures

New procedures for reviewing a sample of Medicare beneficiary complaints about quality of care are compared with traditional procedures at a peer review organization (PRO) for 1998-1999. These new procedures included: (1) expanded communications with complainants and providers, (2) changed data collection methods, (3) integrated concurrent review findings from other agencies, (4) expedited review procedures, and (5) changed the medical review procedures. The findings showed improved beneficiary satisfaction with the new procedures over the traditional procedures and shorter time periods for processing the reviews. Even with the new procedures, beneficiaries continued to be concerned that the review time frames were too lengthy, the reviews generally failed to confirm their complaints, and the PROs generally did not disclose the findings to the beneficiaries.

Nonablative laser skin tightening

This article introduces the reader to the concept of nonablative laser skin tightening with the Cool Touch (Cool Touch Corp., Roseville, CA) laser, a minimally invasive office based procedure. This novel laser system uses dynamic cooling to protect the epidermis while producing a wound healing response in the dermis. Subtle yet positive results have been observed with this laser with minimal down time for patients. The development of this technology and its clinical applications and investigations are discussed.

Evaluation and use of sediment toxicity reference sites for statistical comparisons in regional assessments

Sediment reference sites were used to establish toxicity standards against which to compare results from sites investigated in San Francisco Bay (California, USA) monitoring programs. The reference sites were selected on the basis of low concentrations of anthropogenic chemicals, distance from active contaminant sources, location in representative hydrographic areas of the Bay, and physical features characteristic of depositional areas (e.g., fine grain size and medium total organic carbon [TOC]). Five field-replicated sites in San Francisco Bay were evaluated over three seasons. Samples from each site were tested with nine toxicity test protocols and were analyzed for sediment grain size and concentrations of trace metals, trace organics, ammonia, hydrogen sulfide, and TOC. The candidate sites were found to have relatively low concentrations of measured chemicals and generally exhibited low toxicity. Toxicity data from the reference sites were then used to calculate numerical tolerance limits to be used as threshold values to determine which test sites had significantly higher toxicity than reference sites. Tolerance limits are presented for four standard test protocols, including solid-phase sediment tests with the amphipods Ampelisca abdita and Eohaustorius estuarius and sea urchin Strongylocentrotus purpuratus embryo/larval development tests in pore water and at the sediment-water interface (SWI). Tolerance limits delineating the lowest 10th percentile (0.10 quantile) of the reference site data distribution were 71% of the control response for Ampelisca, 70% for Eohaustorius, 94% for sea urchin embryos in pore water, and 87% for sea urchins embryos exposed at the SWI. The tolerance limits are discussed in terms of the critical values governing their calculation and the management implications arising from their use in determining elevated toxicity relative to reference conditions.

Factors associated with Medicare beneficiary complaints about quality of care

This article examines the number and types of formal complaints about quality of care that were made by Medicare beneficiaries and submitted to the California Peer Review Organization (PRO) during the period July 1, 1995-December 30, 1996. Logistic regression models were used to analyze the complaints in terms of sociodemographic factors, enabling factors (income and health maintenance organization [HMO] membership), diagnoses, and primary service providers. The complaint rate was found to be very low, and only 13% of complaints were confirmed by the PRO. HMO members and members receiving physician care and outpatient/emergency room care were more likely to complain about denials of or delays in services or the failure to be referred to specialists than were members in fee-for-service plans and those receiving other types of provider care. Complaints about poor nursing care were associated with receiving skilled nursing/rehabilitation care. Complaints about care that resulted in injury were associated with the denial of care, failure to be referred to a specialist, poor medical care, and poor communications. Complaints about care that led to disability were associated with medical errors, whereas those that led to death were associated with misdiagnosis and premature hospital discharge. It would be valuable for PROs to focus their complaint review efforts on common types of complaints in different settings. A review of PRO procedures should be undertaken to understand why so few complaints are submitted and confirmed.

Influence of sample manipulation on contaminant flux and toxicity at the sediment-water interface

Toxicities of sediments from San Diego and San Francisco Bays were compared in laboratory experiments using sea urchin (Strongylocentrotus purpuratus) embryos exposed to pore water and at the sediment-water interface (SWI). Toxicity was consistently greater to embryos exposed at the SWI to intact (unhomogenized) sediment samples relative to homogenized samples. Measurement of selected trace metals indicated considerably greater fluxes of copper, zinc, and cadmium into overlying waters of intact sediment samples. Inhibition of sea urchin embryo development was generally greater in sediment pore waters relative to SWI exposures. Pore water toxicity may have been due to elevated unionized ammonia concentrations in some samples. The results indicate that invertebrate embryos are amenable to SWI exposures, a more ecologically relevant exposure system, and that sediment homogenization may create artifacts in laboratory toxicity experiments.

Identification of enteropathogenic Escherichia coli in simian immunodeficiency virus-infected infant and adult rhesus macaques

Enteropathogenic Escherichia coli (EPEC) was recognized as a common opportunistic pathogen of simian immunodeficiency virus-infected rhesus macaques (Macaca mulatta) with AIDS. Retrospective analysis revealed that 27 of 96 (28.1%) animals with AIDS had features of EPEC infection, and EPEC was the most frequent pathogen of the gastrointestinal tract identified morphologically. In 7.3% of animals dying with AIDS, EPEC represented the sole opportunistic agent of the gastrointestinal tract at death. In 20.8% of cases, it was seen in combination with one or more gastrointestinal pathogens, including Cryptosporidium parvum, Enterocytozoon bieneusi, Mycobacterium avium, Entamoeba histolytica, Balantidium coli, Strongyloides stercoralis, cytomegalovirus, and adenovirus. Clinically, infection was associated with persistent diarrhea and wasting and was more frequent in animals that died at under 1 year of age (P < 0.001, Fisher exact test). The organism was associated with the characteristic attaching and effacing lesion in colonic tissue sections and produced a focal adherence pattern on a HEp-2 assay but was negative for Shiga toxin production as assessed by PCR and a HeLa cell cytotoxicity assay. A 2.6-kb fragment encompassing the intimin gene was amplified and sequenced and revealed 99.2% identity to sequences obtained from human isolates (GenBank AF116899) corresponding to the epsilon intimin subtype. Further investigations with rhesus macaques may offer opportunities to study the impact of EPEC on AIDS pathogenesis and gastrointestinal dysfunction.

Effect of combined aspirin and angiotensin-converting enzyme inhibitor therapy versus angiotensin-converting enzyme inhibitor therapy alone on readmission rates in heart failure

An adverse interaction between aspirin and angiotensin-converting enzyme (ACE) inhibitors is suspected in patients with heart failure, but the effect of combined therapy with these agents on hospital readmission rates is unknown. Our study found that combining aspirin with ACE inhibitors is associated with higher early readmission rates than use of ACE inhibitors alone, particularly in patients with depressed ejection fraction and in those without coronary artery disease.

The sensitivity of auditory brainstem response testing for the diagnosis of acoustic neuromas

OBJECTIVES

To determine the sensitivity of auditory brainstem response (ABR) testing for detecting acoustic neuromas and to determine whether the test is less sensitive for detecting small tumors.

DESIGN

Retrospective review of the medical charts of 58 patients with acoustic neuroma who had all of the data necessary for inclusion in the study.

SETTING

University-affiliated referral practice of one neurotologist.

PATIENTS

Patients with acoustic neuromas who had both ABR tracings and magnetic resonance imaging films available for review.

MAIN OUTCOME MEASURES

Positive ABR and negative ABR results correlated with tumor size.

RESULTS

Tumor size ranged from 0.4 to 7 cm. The overall sensitivity of ABR in diagnosing acoustic neuromas was 90%. However, ABR was progressively less sensitive with decreasing tumor size. Only 7 (58%) of the 12 tumors 1 cm or smaller were detected by ABR.

CONCLUSION

Auditory brainstem response testing cannot be relied on for detection of small acoustic neuromas and should not be used as a criterion to determine whether magnetic resonance imaging should be performed when an acoustic neuroma is suspected clinically.

Crystal structure of the haloalkane dehalogenase from Sphingomonas paucimobilis UT26

The haloalkane dehalogenase from Sphingomonas paucimobilis UT26 (LinB) is the enzyme involved in the degradation of the important environmental pollutant gamma-hexachlorocyclohexane. The enzyme hydrolyzes a broad range of halogenated cyclic and aliphatic compounds. Here, we present the 1.58 A crystal structure of LinB and the 2.0 A structure of LinB with 1,3-propanediol, a product of debromination of 1,3-dibromopropane, in the active site of the enzyme. The enzyme belongs to the alpha/beta hydrolase family and contains a catalytic triad (Asp108, His272, and Glu132) in the lipase-like topological arrangement previously proposed from mutagenesis experiments. The LinB structure was compared with the structures of haloalkane dehalogenase from Xanthobacter autotrophicus GJ10 and from Rhodococcus sp. and the structural features involved in the adaptation toward xenobiotic substrates were identified. The arrangement and composition of the alpha-helices in the cap domain results in the differences in the size and shape of the active-site cavity and the entrance tunnel. This is the major determinant of the substrate specificity of this haloalkane dehalogenase.

Medicare beneficiary complaints about quality of care

This study examined all Medicare beneficiary complaints about quality of care submitted to the California Peer Review Organization (PRO) over 18 months. The complaint rate was low, and a medical record review by the PRO only confirmed 13% of the complaints. Managed Care Organization (MCO) members filed significantly more complaints about denial and/or delays in receiving services and the failure to refer to specialists. Fee-for-service complaints focused on inpatient hospital services, particularly premature discharge, discharge planning, admission necessity, and unnecessary tests. The PRO review process took over 7 months, and the findings were generally not released to the complainants.

Oxygen dependency and precision of cytochrome oxidase signal from full spectral NIRS of the piglet brain

Oxidation changes of the copper A (Cu(A)) center of cytochrome oxidase in the brain were measured during brief anoxic swings at both normocapnia and hypercapnia (arterial PCO(2) approximately 55 mmHg). Hypercapnia increased total hemoglobin from 37.5 +/- 9.1 to 50.8 +/- 12.9 micromol/l (means +/- SD; n = 7), increased mean cerebral saturation (Smc(O(2))) from 65 +/- 4 to 77 +/- 3%, and oxidized Cu(A) by 0.43 +/- 0.23 micromol/l. During the onset of anoxia, there were no significant changes in the Cu(A) oxidation state until Smc(O(2)) had fallen to 43 +/- 5 and 21 +/- 6% at normocapnia and hypercapnia, respectively, and the maximum reduction during anoxia was not significantly different at hypercapnia (1.49 +/- 0.40 micromol/l) compared with normocapnia (1.53 +/- 0.44 micromol/l). Residuals of the least squares fitting algorithm used to convert near-infrared spectra to concentrations are presented and shown to be small compared with the component of attenuation attributed to the Cu(A) signal. From these observations, we conclude that there is minimal interference between the hemoglobin and Cu(A) signals in this model, the Cu(A) oxidation state is independent of cerebral oxygenation at normoxia, and the oxidation after hypercapnia is not the result of increased cerebral oxygenation.

Sporadic primary pulmonary hypertension is associated with germline mutations of the gene encoding BMPR-II, a receptor member of the TGF-beta family

BACKGROUND

Primary pulmonary hypertension (PPH), resulting from occlusion of small pulmonary arteries, is a devastating condition. Mutations of the bone morphogenetic protein receptor type II gene (BMPR2), a component of the transforming growth factor beta (TGF-beta) family which plays a key role in cell growth, have recently been identified as causing familial PPH. We have searched for BMPR2 gene mutations in sporadic PPH patients to determine whether the same genetic defect underlies the more common form of the disorder.

METHODS

We investigated 50 unrelated patients, with a clinical diagnosis of PPH and no identifiable family history of pulmonary hypertension, by direct sequencing of the entire coding region and intron/exon boundaries of the BMPR2 gene. DNA from available parent pairs (n=5) was used to assess the occurrence of spontaneous (de novo) mutations contributing to sporadic PPH.

RESULTS

We found a total of 11 different heterozygous germline mutations of the BMPR2 gene in 13 of the 50 PPH patients studied, including missense (n=3), nonsense (n=3), and frameshift (n=5) mutations each predicted to alter the cell signalling response to specific ligands. Parental analysis showed three occurrences of paternal transmission and two of de novo mutation of the BMPR2 gene in sporadic PPH.

CONCLUSION

The sporadic form of PPH is associated with germline mutations of the gene encoding the receptor protein BMPR-II in at least 26% of cases. A molecular classification of PPH, based upon the presence or absence of BMPR2 mutations, has important implications for patient management and screening of relatives.

Preventing fungal infections in immunocompromised patients

The incidence of systemic fungal infections in immunosuppressed patients has increased in the past two decades (Fridkin and Jarvis, 1996). Bone marrow transplant recipients and patients with prolonged neutropenia are most at risk, particularly when environmental factors increase the presence of fungi and fungal spores. Preventive measures include air filtration, handwashing, exclusion of flowers and some foodstuffs and use of chemoprophylaxis. In April 1999, a meeting was held under the auspices of the European Group for Blood and Marrow Transplantation (UK) Nurses and Allied Professionals Group to discuss the role of nurses in the management of patients at risk of systemic fungal infection. Issues discussed included: the need for nurses to recognize risk factors for systemic fungal infection; the role of nurses in giving feedback to patients; and the use of antifungal agents and associated problems, such as non-compliance and side-effects.