The associations between working conditions and subjective sleep quality among female migrant care workers

Background

Subjective sleep quality may reflect the mental well-being of migrant care workers; however, the related occupational factors remain unclear. This study examines the association between the characteristics of care labor and the subjective sleep quality of female migrants.

Methods

In this cross-sectional study, Southeast Asian migrant care workers in Taiwan were recruited using convenience sampling. Data on working conditions, including workplace setting, wage, working hours, psychiatric symptoms of care recipients, and sleep quality measured using the Pittsburgh Sleep Quality Index (PSQI), were collected through computer-assisted personal interviews. Multiple linear regression analyses were performed to determine the independent relationship between working conditions and the PSQI global score.

Results

There were 220 institution-(47.7%) and home-based (52.3%) care workers, and 47.7% had a PSQI score higher than 5. After controlling for covariates, the lowest tertile of wages and daily working hours (> 8 h) were independently correlated with poor sleep quality. Moreover, in the stepwise regression model, wage and working hours remained the most explainable correlates of poor sleep quality.

Conclusion

This study lent support to the notion that low wages and long working hours are significant occupational factors that negatively impact the subjective sleep quality of female Southeast Asian migrant care workers in Taiwan.

Personality mediates the association between juvenile conduct problems and adulthood mood disorders

This study aimed to examine the association between conduct problems and mood disorders, and to evaluate the mediating roles of personality traits in it. Adult participants (N = 309), for which patients with major depressive disorder (MDD) or bipolar disorder (BD), and controls without major psychiatric history were recruited. Juvenile conduct problem was defined by the items in Composite International Diagnosis Interview. We assessed personality traits of extraversion and neuroticism. Multiple mediation model was performed to investigate the intervening effect of personality traits between juvenile conduct problems and adulthood mood disorders. Participants had on average 2.7 symptoms of conduct problems, and 43.4% had conduct problems. Having more symptoms of conduct problems was associated with a higher likelihood of BD (OR = 1.20). Higher neuroticism was associated with elevated risks of both MDD and BD. There was no direct effect of binary conduct problems on the risk of BD, and showed significant total indirect effect mediated by neuroticism for BD (OR = 1.49; bias-corrected and accelerated 95% CI = 1.10–2.05), but not through extraversion. Conduct problems defined as a continuous variable had a direct effect on the risk of adult MDD (OR = 1.36; bias-corrected and accelerated 95% CI = 1.05–1.76), while had an indirect effect on the risk of BD via the mediation of neuroticism (OR = 1.08; bias-corrected and accelerated 95% CI = 1.02–1.14). Neuroticism mediates between the association of juvenile conduct problems and adult BD. This finding raises our attention to assess personality traits in individuals with juvenile conduct problems for timely intervention strategies of reducing the vulnerability for developing mood disorders.

421 Closed loop analgesia audit, a Single Centre Experience in Raigmore Hospital, Inverness, Scotland

Aim

Assess are we following the analgesic step ladder accurately and if not are the reasons clear and documented?

Method

A closed-loop audit performed on the use of the WHO Analgesic ladder in surgical patients. We looked at the compliance of the analgesic ladder and are the reasons documented or explained when the ladder is not followed. The data was collated, analysed, and presented at an audit meeting. We then implemented changes in the form of educational sessions and information leaflets sharing, as well as email reminders among staff. Post-implementation showed an improvement in the documentation when the analgesic ladder was not followed.

Results

A total of 103 surgical patients were included. Prior to the implementation of interventions, 83.3% of patients had analgesia prescribed following the analgesic ladder. Of those remaining patients who had analgesia prescribed not according to the analgesic ladder, only 50% documented the indications and reasons. Post-implementation, the analgesic ladder compliance dropped to 50.9% with documentation improvement to 56%.

Conclusions

All surgical patients have prescribed analgesia when needed. Though WHO ladder compliance has shown reduction compared to the first data sample, the reasons are clinically justified, and improvements have been shown in documentation after intervention though there is still room for improvement for documentation. This is perhaps surgical teams are more aware of the choice of analgesia used post-intervention while taking the analgesic ladder into consideration. Stepwise multimodal analgesia prescribing will improve analgesic effect hence improves post-operative recovery hence reduce the length of hospital stay as part of the ERAS protocol.

Premenstrual dysphoric symptoms and lifetime suicide experiences in patients with mood disorder

BACKGROUND

Premenstrual dysphoric symptoms (PMDS) commonly co-occurred with mood disorders and correlated with suicide experiences in women. This study aims to examine the associations between PMDS and lifetime suicide experiences in patients with mood disorders.

METHODS

Participants were recruited from outpatient settings of two medical centers and one psychiatric hospital in Taiwan. Women aged 18-65 in non-acute state of major depressive disorder or bipolar affective disorder were recruited. PMDS and lifetime suicide experiences were defined by the Schedule for Affective Disorder and Schizophrenia-Lifetime. Lifetime suicide experiences were defined as no suicide experience, suicide plans only and suicide attempts.

RESULTS

A total of 383 women participated in this study (54.8% of them were diagnosed with major depressive disorder), and 13.8% were diagnosed with PMDS. The prevalence of patients with lifetime suicide plans only and lifetime suicide attempts were 15.9% and 39.7%, respectively. In the univariate analysis, PMDS was correlated with lifetime suicide experience. After controlling for covariates, PMDS was a risk indicator for lifetime suicide attempts (OR: 3.46, 95% CI: 1.43-8.38) but not for suicide plans only (OR: 0.93, 95% CI: 0.28-3.11).

CONCLUSIONS

PMDS correlated with lifetime suicide experiences in women with non-acute mood disorders. In particular, PMDS exhibited as an independent correlate for lifetime suicide attempts.

Tumefactive demyelinating lesions by combined perfusion-weighted and diffusion weighted imaging

Tumefactive demyelinating lesion may sometimes mimic intracranial neoplasm or abscess and pose a diagnostic problem both clinically and radiologically. The diagnosis is even more complicated since multiple sclerosis is relatively uncommon among Chinese and due to low incidence of oligoclonal protein in the cerebrospinal fluid. We present a Chinese lady with tumefactive demyelinating lesion, which mimic cystic neoplasm and cerebral abscess. The use of perfusion and diffusion weighted imaging obviated unnecessary surgical biopsy.

Evaluation of cerebral abscesses by diffusion-weighted MR imaging and MR spectroscopy

Cerebral abscess may sometimes mimic necrotic tumor and cystic metastases both clinically and radiologically. The imaging findings may be indistinguishable on conventional magnetic resonance imaging. Although recent studies have shown that cerebral abscess displays restricted diffusion on diffusion-weighted imaging (DWI), it is not pathognomic. Necrotic tumor and cystic metastases may occasionally have restricted diffusion on DWI. Since the urgency of surgical intervention and approach of surgery is different, MR Spectroscopy may be used in conjunction with DWI in establishing the correct diagnosis.

Late temporal lobe necrosis in patients with nasopharyngeal carcinoma: evaluation with combined multi-section diffusion weighted and perfusion weighted MR imaging

Late temporal lobe necrosis is a well-known and serious complication in patients with nasopharyngeal carcinoma (NPC) following radiotherapy. Owing to the close proximity to the skull base, the medial temporal lobes are inevitably included in the target volume of irradiation. Patients with NPC provide a unique opportunity in study of delay radiation effect in normal human brain. The objective of this study was to evaluate late temporal lobe radiation injury by combined multi-section diffusion weighted and perfusion weighted MR imaging. We prospectively studied 16 patients with typical clinical symptoms of late temporal lobe necrosis or other abnormalities in the temporal lobes incidentally detected by conventional MR imaging. All patients had a previous history of radiotherapy for histologically proven NPC. Conventional T1- and T2-weighted images, fast gradient echo with echo-planar diffusion-weighted and perfusion-weighted MR imaging were performed. Apparent diffusion coefficient (ADC) map and relative cerebral blood volume (rCBV) map were computed via commercially available software. MR diffusion and perfusion images were then analyzed and graded by two independent observers with focusing on the diffusion and perfusion mismatch. The temporal lobe lesions displayed marked high diffusion on the ADC map. The rCBV map also revealed marked hypoperfusion in these temporal lobe lesions in all patients. The areas of abnormality on the rCBV map were significantly larger than the lesions on the ADC map in 14 patients (observer 1) and 13 patients (observer 2). Since late temporal lobe necrosis is probably caused by damage of the endothelium of vessels and ischemia, perfusion and diffusion mismatch might imply injured tissue but potentially salvageable brain tissue. A mismatch may be potentially used to predict the response to treatment in-patients with late temporal lobe necrosis.

Effect of ABO blood group mismatching on corneal epithelial cells: an in vitro study

AIM

To determine, in vitro, the effects of blood group ABO mismatching on corneal epithelial cells.

METHODS

Corneal epithelial cell cultures were established from 32 human cadaver donor eyes. Epithelial cells (100 microl of 4 x 10(2) cells per microl) were incubated for 4 hours with antibodies against blood group antigens A, B, and AB, with and without complement. Cell lysis was assayed by a chemiluminescent assay using Cytolite reagent. Live cells, remaining after incubation, were counted in a scintillation counter. The blood group of the donors was determined retrospectively, in a blinded manner.

RESULTS

Retrospective tracing of donor blood groups was possible for 20 donors. In all cases the blood group corresponded with that suggested by the cell lysis assay. Significant cell lysis was observed when known A group cells were incubated with anti-A and anti-AB antibody, B group cells were incubated with anti-B and AB antibody, and AB group cells were incubated with anti-AB antibody. Lysis occurred only in the presence of complement. No lysis of O group cells was observed with any of the antibodies. In all cases, lysis was observed only with neat (serum) antibody concentrations.

CONCLUSIONS

Blood group ABO mismatching results in significant lysis of corneal epithelial cells. The antibody concentration required for lysis equals that found in serum. Such levels of antibody are unlikely to be achieved in tears and/or aqueous. This may offer an explanation for the conflicting reports of the studies on the effect of blood group matching on corneal grafts. The variability in the outcome may reflect the levels of antibodies gaining access to the corneal cells and not the mismatching alone.

X-Ray crystal structures of Candida albicans dihydrofolate reductase: high resolution ternary complexes in which the dihydronicotinamide moiety of NADPH is displaced by an inhibitor

X-ray crystallographic analysis of 5-(4'-substituted phenyl)sulfanyl-2,4-diaminoquinazoline inhibitors in ternary complex with Candida albicans dihydrofolate reductase (DHFR) and NADPH revealed two distinct modes of binding. The two compounds with small 4'-substituents (H and CH3) were found to bind with the phenyl group oriented in the plane of the quinazoline ring system and positioned adjacent to the C-helix. In contrast, the more selective inhibitors with larger 4'-substituents (tert-butyl and N-morpholino) were bound to the enzyme with the phenyl group perpendicular to the quinazoline ring and positioned in the region of the active site that typically binds the dihydronicotinamide moiety of NADPH. The cofactor appeared bound to DHFR but with the disordered dihydronicotinamide swung away from the protein surface and into solution. This unusual inhibitor binding mode may play an important role in the high DHFR selectivity of these compounds and also may provide new ideas for inhibitor design.

N-hydroxyformamide peptidomimetics as TACE/matrix metalloprotease inhibitors: oral activity via P1' isobutyl substitution

N-Hydroxyformamide-class metalloprotease inhibitors were designed and synthesized, which have potent broad-spectrum activity versus matrix metalloproteases and TNF-alpha converting enzyme (TACE). Compound 13c possesses good oral and intravenous pharmacokinetics in the rat and dog.

2-Amino-6-arylsulfonylbenzonitriles as non-nucleoside reverse transcriptase inhibitors of HIV-1

A series of 2-amino-5-arylthiobenzonitriles (1) was found to be active against HIV-1. Structural modifications led to the sulfoxides (2) and sulfones (3). The sulfoxides generally showed antiviral activity against HIV-1 similar to that of 1. The sulfones, however, were the most potent series of analogues, a number having activity against HIV-1 in the nanomolar range. Structural-activity relationship (SAR) studies suggested that a meta substituent, particularly a meta methyl substituent, invariably increased antiviral activities. However, optimal antiviral activities were manifested by compounds where both meta groups in the arylsulfonyl moiety were substituted and one of the substituents was a methyl group. Such a disubstitution led to compounds 3v, 3w, 3x, and 3y having IC50 values against HIV-1 in the low nanomolar range. When gauged for their broad-spectrum antiviral activity against key non-nucleoside reverse transcriptase inhibitor (NNRTI) related mutants, all the di-meta-substituted sulfones 3u-z and the 2-naphthyl analogue 3ee generally showed single-digit nanomolar activity against the V106A and P236L strains and submicromolar to low nanomolar activity against strains E138K, V108I, and Y188C. However, they showed a lack of activity against the K103N and Y181C mutant viruses. The elucidation of the X-ray crystal structure of the complex of 3v (739W94) in HIV-1 reverse transcriptase showed an overlap in the binding domain when compared with the complex of nevirapine in HIV-1 reverse transcriptase. The X-ray structure allowed for the rationalization of SAR data and potencies of the compounds against the mutants.

Idiopathic pulmonary artery aneurysm: digital subtraction pulmonary angiography grossly underestimates the size of the aneurysm

Pulmonary artery aneurysm is a rare disease entity. The majority of cases are associated with congenital cardiovascular diseases, infection, and trauma; idiopathic pulmonary artery aneurysm is extremely rare. Although conventional and digital subtraction pulmonary angiography remains as the imaging modality of choice for the pulmonary vessels, it is invasive and sometimes may be inaccurate. With the advent of spiral computed tomographic angiography (CTA), pulmonary artery aneurysm can be diagnosed noninvasively and accurately. We report a case of a 68-year-old man with idiopathic pulmonary artery aneurysm of the descending branch of right pulmonary artery where the true caliber of the aneurysm was significantly underestimated in the digital subtraction pulmonary angiography. The literatures of this rare condition are reviewed with the emphasis on the application of CTA in this disease.

Artifacts in musculoskeletal magnetic resonance imaging: identification and correction

A large number of artifacts occur in magnetic resonance (MR) imaging of the musculoskeletal system. These artifacts may potentially affect the quality of MR images, and may also simulate pathologic conditions and produce pitfalls in interpretation. Motion artifacts may be periodic or random. Protocol-error artifacts include saturation, wraparound, radiofrequency (RF) interference, shading, and partial volume averaging artifacts. Truncation artifacts occur when the number of phase-encoding steps of high spatial frequencies is insufficient (or under-sampled) for faithful reproduction of the true anatomic detail of the original image. Chemical shift artifacts are due to the protons in fat being mismapped relative to water protons. Susceptibility artifacts occur at the interfaces of structures with different magnetic susceptibilities. Artifacts special to the musculoskeletal system include the magnic angle phenomenon and spurious signal induced at very short echo times, both of which affect anisotropic structures such as tendon, ligament, and cartilage. Recognition and, if possible, correction of these artifacts are an important aspect of practical musculoskeletal MR imaging.

Diffusion-weighted MR imaging of the liver: distinguishing hepatic abscess from cystic or necrotic tumor

BACKGROUND

We evaluated the ability of diffusion-weighted (DW) magnetic resonance (MR) imaging to differentiate between hepatic abscess and cystic or necrotic liver tumor.

METHODS

DW MR imaging was performed in 18 patients who had liver masses with large cystic or necrotic cavities detected by computed tomography or ultrasonography. The final diagnoses were pyogenic abscess (five cases), fungal abscess (one), hepatocellular carcinoma (five), cystic metastasis (four), and hepatic cyst (three). Signal intensities on the DW images and apparent diffusion coefficient (ADC) maps were noted. ADCs in all lesions were calculated and compared with Student's t test.

RESULTS

All lesions, except hepatic cysts, showed either heterogeneous or homogeneous rim enhancement on postgadolinium images. All abscess cavities showed hyperintensity on DW images and hypointensity on ADC maps. Conversely, the cystic or necrotic portions of all tumors showed hypointensity on DW images and hyperintensity on ADC maps. The mean ADCs (mm(2)/s) were 0.67 +/- 0.35 x 10(-3) in hepatic abscess, 2.65 +/- 0.49 x 10(-3) in cystic or necrotic tumor, 2.93 +/- 0.52 x 10(-3) in hepatic cyst, and 1.98 +/- 0.37 x 10(-3) in normal liver parenchyma.

CONCLUSION

DW MR imaging, with the help of ADCs, may be a useful noninvasive imaging technique in differentiating hepatic abscess from cystic or necrotic tumor.

MR diffusion-weighted imaging of kidney: differentiation between hydronephrosis and pyonephrosis

The objective of the study was to evaluate the capability and reliability of the magnetic resonance (MR) diffusion-weighted imaging (DWI) in differentiation between hydronephrosis and pyonephrosis. Single-shot echoplanar MR diffusion-weighted imaging was performed in 12 patients who had dilatation of the renal pelvis and calyces detected by ultrasonography (US). Microbiological tests confirmed that there were four cases of pyonephrosis and eight cases of hydronephrosis. Signal intensities of the collecting (pelvicalyceal) systems on the diffusion-weighted images and apparent diffusion coefficient (ADC) maps were noted. ADC values of the pelvicalyceal system in all patients were computed and compared using Student's t test. On diffusion-weighted images, the pelvicalyceal system of the hydronephrotic kidney was hypointense while the pelvicalyceal system of the pyonephrotic kidney was markedly hyperintense. The mean ADCs of the hydronephrotic and pyonephrotic renal pelvis were 2.98 +/- 0.65 x 10(-3) and 0.64 +/- 0.35 x 10(-3) mm(2)/s, respectively. The extremely low ADC of the renal pelvis of the pyonephrotic kidney accounted for its signal hyperintensity on diffusion-weighted images as well as signal hypointensity on ADC maps. In conclusion, the MR diffusion-weighted imaging may be a reliable tool to differentiate pyonephrosis from hydronephrosis.

Rapid spontaneous resolution and redistribution of acute subdural hematoma in a patient with chronic alcoholism: a case report

We report a case of a 54-year-old man who had documented traumatic acute subdural hematoma. He suffered from a transient episode of confusion and a follow-up CT scan of brain 6 h after the initial scan showed resolution and redistribution of the subdural hematoma. In this case report, we review the literature for the underlying pathophysiology of this uncommon phenomenon.

Cognitive function of patients with nasopharyngeal carcinoma with and without temporal lobe radionecrosis

BACKGROUND

Radiotherapy is the primary treatment for nasopharyngeal carcinoma, and temporal lobe necrosis is observed in about 7% of patients after radiotherapy. Although some studies reported that these patients demonstrated cognitive impairment after radiotherapy, it is still unclear if the cognitive deficits are related to the radiation exposure or the radiation-induced necrosis.

OBJECTIVE

To compare the cognitive function of patients with and without temporal lobe necrosis after radiotherapy for nasopharyngeal carcinoma.

METHODS

A comprehensive neuropsychological battery was administered to 53 patients with nasopharyngeal carcinoma who had completed their radiotherapy at least 1 year previously. As evidenced by magnetic resonance imaging, 31 patients developed necrosis after treatment. Thirty-one age- and education-matched individuals were recruited as normal control subjects.

RESULTS

Whereas the performance of patients without temporal lobe necrosis was similar to that of normal control subjects, patients with temporal lobe necrosis demonstrated significant impairment on tests of verbal (P<.001) and visual memory (range, P<.001 to P =.03), language (range, P<.001 to P =.01), motor ability (P =.02), planning (P =.02), cognitive ability (P =.007), and abstract thinking (range, P =.009 to P =.04). However, the performance of patients with necrosis on tests of general intelligence (range, P =.08 to P =.15), attention (range, P =.06 to P =.55), and visual abilities (range, P =.06 to P =.47) was not significantly different from that of normal control subjects and patients without necrosis.

CONCLUSIONS

Radiotherapy for nasopharyngeal carcinoma seemed to have adverse but insignificant effects on the cognitive functions of the patients. However, for patients who developed temporal lobe necrosis after radiotherapy, memory, language, motor ability, and executive functions were significantly impaired, although their general intelligence remained relatively intact.

Evaluation of therapeutic effectiveness of transarterial chemoembolization for hepatocellular carcinoma: correlation of dynamic susceptibility contrast-enhanced echoplanar imaging and hepatic angiography

The objective of this study was to evaluate the therapeutic effectiveness of transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) with dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI). Seventeen patients with histopathologically proven HCC were included in this study. All patients underwent MR examinations with conventional T1- and T2-weighted images, gadolinium-enhanced images, and DSC-MRI before TACE treatment. Hepatic blood volume (HBV) maps were reconstructed from the time-intensity curves. The same MRI sequences and techniques were repeated 24 h and 6 weeks after TACE. Serial changes in tumor perfusion on HBV maps were correlated with vascularity in hepatic angiography. All tumors were hypointense on T1-weighted images and hyperintense on T2-weighted images. Heterogeneous enhancement was observed in all tumors before and immediately after TACE. Hyperperfusion was noted in most of the tumors on HBV map before TACE and moderate to marked hypoperfusion following TACE. The degree of tumor perfusion on HBV map correlated well with the vascularity in angiography. In conclusion, the noninvasive nature of DSC-MRI is useful to evaluate the effectiveness of TACE. Invasive procedures, such as angiography, are seldom necessary.

Gadopentetate dimeglumine as an oral negative gastrointestinal contrast agent for MRCP

BACKGROUND

We investigated the feasibility of using intravenous magnetic resonance (MR) contrast agent as a gastrointestinal oral negative contrast agent to null the bowel signal during MR cholangiopancreatography (MRCP).

METHODS

In the first part of the study, a phantom study was performed to select the optimal concentration of MR contrast agent to be used as an oral negative contrast agent in MRCP. In the second part of the study, 23 consecutive patients suffering from different pancreaticobiliary diseases were imaged with a single-shot fast spin-echo pulse sequence. The data acquisition was started without oral contrast agent and then repeated with oral contrast agent. From the MR images taken with and without oral contrast agent, the gallbladder, cystic duct, common bile duct, and pancreatic duct were assessed and graded by two radiologists.

RESULTS

The oral contrast agent was tolerated well by all patients. In all patients the high signal intensity from the intestinal fluid was completely suppressed. The depictions of the gallbladder and cystic duct were slightly and moderately improved, respectively, whereas the depictions of the common bile duct and pancreatic duct were markedly improved by the oral contrast agent administration.

CONCLUSION

Diluted intravenous MR contrast agent can be an effective and safe oral negative contrast agent in eliminating signal intensity of the gastrointestinal tract, thus improving the depiction of the biliary system in MRCP.

Radionecrosis of the temporal lobe: dynamic susceptibility contrast MRI

We examined nine patients with histologically proven nasopharyngeal carcinoma (NPC), treated with radiotherapy, using dynamic susceptibility contrast MRI (DSC-MRI). In eight there was clinical evidence of radionecrosis of the temporal lobe, and one was examined for local recurrence in the nasopharynx. All patients had either high-signal finger-like or cystic lesions in the temporal lobes on T2-weighted images. Heterogeneous contrast enhancement occurred in all patients. Relative regional cerebral blood volume (rrCBV) mapping revealed marked hypoperfusion in all patients. One underwent bilateral temporal lobectomy and radionecrosis was confirmed histologically.

Synthesis and evaluation of a series of 2'-deoxy analogues of the antiviral agent 5,6-dichloro-2-isopropylamino-1-(beta-L-ribofuranosyl)-1H-benzimidazole (1263W94)

A series of 2'-deoxy analogues of the antiviral agent 5,6-dichloro-2-isopropylamino-1-(beta-L-ribofuranosyl)-1H-benzimidazole (1263W94) were synthesized and evaluated for activity against human cytomegalovirus (HCMV) and for cytotoxicity. The 2-substituents in the benzimidazole moiety correspond to those that were used in the 1263W94 series. In general, as was found in the 1263W94 series, cyclic and branched alkylamino groups were needed for potent activity against HCMV. Three analogues 3a, 3b and 3d were as potent as 1263W94. Further evaluation of two analogues, 3a and 3b, suggested that these 2'-deoxy analogues may act via a novel mechanism of action similar to that of 1263W94. These 2'-deoxy analogues generally lacked cytotoxicity in vitro. Pharmacokinetic parameters in mice and protein binding properties of 3a were quite similar to 1263W94. However, the oral bioavailability of 3a was only half of that observed for 1263W94.

Microfabricated polymer devices for automated sample delivery of peptides for analysis by electrospray ionization tandem mass spectrometry

Delivery of proteins and peptides to electrospray ionization mass spectrometers (ESI-MS) has been demonstrated using glass and quartz microfabricated devices. This paper reports the construction and use of poly(dimethylsiloxane) (PDMS) microfabricated soft polymer devices with mass spectrometry for protein analysis. The PDMS devices were fabricated using replica molding against a patterned photoresist generated by photolithographic techniques. The PDMS devices were connected to the mass spectrometer via a derivatized transfer capillary and samples were transferred by electroosmotic pumping. The formulation of PDMS was optimized for compatibility with ESI, and the devices were tested for performance. The practical application of PDMS devices was demonstrated by the identification of rat serum albumin separated by 2-D gel electrophoresis. Extended contact of the sample with the surface of the PDMS device did not significantly affect the sample analysis, and the limit of detection for samples run on a PDMS device was comparable to the limit of detection achieved on glass devices. This study suggests that PDMS devices fabricated using replica molding are compatible with ESI-MS. This will potentially lead to the construction of inexpensive microfabricated devices with complex designs and advanced functionalities.

MR imaging of breast paraffinomas

OBJECTIVE

Our objective is to present the MR appearance of breast paraffinoma, a late complication of breast augmentation by liquid paraffin wax, and to correlate this appearance with the histopathologic findings that were available for three of the 11 breasts we studied.

CONCLUSION

Breast paraffinomas have a characteristic MR appearance that correlates well with histopathologic findings. With MR imaging, we were able to visualize the location and extent of the paraffinoma, best seen on the fat-suppression sequence, and to evaluate the surrounding fibroglandular breast tissue.

Breath-hold 3D gadolinium-enhanced subtraction MRA in the detection of transplant renal artery stenosis

AIMS

The purpose of this study was to assess the value of breath-hold 3D gadolinium-enhanced subtraction magnetic resonance angiography (GD-MRA) in the detection of transplant renal artery stenosis (TRAS).

PATIENTS AND METHODS

Seven patients with suspected post-transplant renal artery stenosis were studied. GD-MRA was performed at 1.5T with a 3D fast spoiled gradient recalled echo (FSPGR) pulse sequence. Before injection of contrast medium, the 3D pulse sequence was performed to obtain a set of non-contrast images for subtraction purposes. Dynamic 3D imaging was performed simultaneously with the bolus injection of 40 ml of gadopentetate dimeglumine. Angiographic images were reconstructed using the Advantage Window workstation (version 2.0 GE Medical Systems) and subtraction was made with the pre-contrast image data. Any signal intensity cut-off or narrowing of more than 50% was regarded as significant stenosis. Ultrasound Doppler (USD) study was performed with both colour and spectral studies. Peak systolic velocity (PSV) of greater than 2.0 m/s and acceleration time (AT) greater than 120ms was regarded as positive for TRAS. These were then compared with the digital subtraction angiography (DSA) as the gold standard.

RESULTS

A total of nine examinations performed in seven patients were included in the analysis. MRA correlated with the DSA findings in eight examinations, with one false negative. USG correlated with DSA in six examinations, with two false negative and one false positive case.

CONCLUSION

In our opinion, GD-MRA is a promising and non-invasive technique in the detection of TRAS.

Determining the lumbar vertebral segments on magnetic resonance imaging

STUDY DESIGN

A study to test the ability of an additional cervicothoracic localizer scan to decrease interobserver discrepancy in the identification of vertebral segments in magnetic resonance imaging of the lumbar spine.

OBJECTIVES

To investigate whether lumbar vertebral segments can be identified correctly from lumbosacral magnetic resonance localizer scans, the degree of interobserver discrepancy, and the value of an additional cervicothoracic localizer scan.

SUMMARY OF BACKGROUND DATA

In magnetic resonance imaging of the lumbar spine, it may be difficult to identify transitional lumbosacral vertebral segments.

METHODS

The sagittal and coronal lumbosacral localizer scans of 141 consecutive patients referred for magnetic resonance imaging of the lumbosacral spine were reviewed independently by two radiologists with the aim of locating the L5 vertebra. An additional sagittal cervicothoracic localizer scan also was performed in each case. The final study group consisted of 129 patients. The L5 vertebra was identified by counting caudally from C2 using the sagittal cervicothoracic and lumbosacral localizer scans. In the 54 most recently studied patients, cod liver oil capsule surface markers were placed near the thoracolumbar junction to quantify any marker shift between the two sagittal localizer scans.

RESULTS

The lumbar segments could be identified consistently by counting caudally using cervicothoracic and lumbosacral localizer scans. Using sagittal lumbosacral localizer scans alone, the lumbar vertebral segments could be identified correctly in only 80.2% of patients. Coronal lumbosacral localizer scans produced similar results (82.2%). The accuracy fell to 77.9% when using a combination of both sagittal and coronal lumbosacral localizer scans. There was a 11.6% interobserver discordance in assessment of these levels. Lumbosacral transitional vertebrae were identified in 17 patients (13.2%), including 8 sacralized L5 and 9 lumbarized S1 vertebrae. Apparent surface-marker shift between cervicothoracic and lumbosacral localizer scans was insignificant, averaging only 1.9 mm (range, 0.0-5.6 mm).

CONCLUSIONS

The addition of a cervicothoracic localizer scan in magnetic resonance imaging of the lumbosacral spine is highly recommended.

Hypertrophic olivary degeneration following surgical excision of brainstem cavernous hemangioma: a case report

Hypertrophic olivary degeneration (HOD) is a rare type of neuronal degeneration involving the dento-rubo-olivary pathway. It is distinguished from other types of neuronal degeneration in that hypertrophy, rather than atrophy, takes place in the neurons in the inferior olivary nucleus. Prior to the invention of Magnetic Resonance Imaging (MRI), HOD was difficult to be detected, and a firm diagnosis could only be made at autopsy. We present a case of bilateral HOD following surgical excision of a cavernous hemangioma in the brainstem. The literature and imaging findings of this uncommon condition are reviewed.

Detection of hepatic tumor perfusion following transcatheter arterial chemoembolization with dynamic susceptibility contrast-enhanced echoplanar imaging

The aim of the study was to evaluate the usefulness of the magnetic resonance (MR) perfusion maps in the detection of liver tumor perfusion following transcatheter arterial chemoembolization (TACE). MR dynamic susceptibility contrast-enhanced imaging was performed in 12 patients with 10 confirmed hepatocellular carcinoma and 2 confirmed hepatic metastasis using single-shot echoplanar pulse sequence. Time-intensity curves for all hepatic tumors showed a transient signal drop and the hepatic blood volume (HBV) maps were reconstructed. On the HBV maps, most tumors (80%) demonstrated hyperperfusion before TACE and hypoperfusion following TACE. The site and the degree of residual hyperperfusion within the tumor on the HBV maps correlated well with the areas of hypervascularity on the angiograms. In conclusion, the MR perfusion maps can be a promising technique for detecting the perfusion of the residual tumor tissue following TACE.

The effect of using shorter echo times in MR imaging of knee menisci: a study using a porcine model

OBJECTIVE

Increasingly shorter TEs are being used for T1-weighted and proton density-weighted sequences in MR imaging of the knee. This study aims to evaluate the effect of a short TE on meniscal signal intensity.

MATERIALS AND METHODS

Thirty porcine knees were imaged with a 1.5-T MR scanner using spin-echo T1-weighted and proton density-weighted sequences. TR was kept constant at 700 msec for T1-weighted and 2200 msec for proton density-weighted sequences. For each set of sequences, sagittal images were obtained using these TE values: 9, 12, 16, 20, and 25 msec. Imaging parameters, such as slice thickness and interslice gap, number of excitations, matrix size, and field of view, were identical for each set of sequences. Using a fixed window level and width, we assessed the anterior and posterior horns of the medial meniscus for signal hyperintensity at each TE value. Signal intensity was also measured in eight knees. The menisci were then dissected and examined grossly and histopathologically.

RESULTS

Intrameniscal signal intensity increased progressively with shorter TEs. At a TE of 9 msec, signal hyperintensity was present in 100% of T1-weighted and 96.7% of proton density-weighted images. At a TE of 12 msec, signal hyperintensity was seen in 86.7% of T1-weighted and 80% of proton density-weighted images. At a TE of 16 msec, increased signal intensity was seen in only 3.3% of T1-weighted and 6.6% of proton density-weighted images. At TEs of 20 and 25 msec, increased signal intensity was seen in none of the T1-weighted and proton density-weighted images. Meniscal signal intensity increased exponentially at very short TE values. All menisci were found to be normal on gross and histopathological examination.

CONCLUSION

Spurious signal hyperintensity appears in normal menisci at short TE values. Images acquired with short TEs should be interpreted with caution, and a TE of 16 msec or more is recommended.

Lumbar spine magnetic resonance imaging: comparison between fast spin echo proton density and spin echo T1 axial scans

Spin echo (SE) T1 axial scans are routinely obtained in magnetic resonance imaging of the lumbar spine in many centres. This study directly compared matched SE T1 and fast SE (FSE) proton density (PD) axial scans. Both SE T1 and FSE PD axial scans of the lumbar spine were obtained in 116 consecutive patients. The imaging parameters (field-of-view, slice thickness, interslice gap, number of excitations and matrix size) and scan levels were identical for each pair of sequences. At two selected levels, L4/5 and L5/S1, various structures were independently graded by two observers. In 232 lumbar levels analysed, the bone marrow, epidural fat, disc, extradural nerve root and facet joint were equally well seen on both sequences by both observers (combined mean grades of 2.93-2.99). The thecal sac was marginally better depicted on FSE PD than on SE T1 images, with mean grades of 2.96 and 2.88, respectively. The psoas muscle was adequately visualized for diagnostic purposes on both sequences (mean grades of 2.30-2.32). The cauda equina were better seen on FSE PD (mean grade 1.92) than on SE T1 (mean grade 1.00) images. In conclusion, FSE PD scans are comparable to and may potentially replace SE T1 axial MR scans of the lumbar spine.

The magic angle phenomenon in tendons: effect of varying the MR echo time

Increased signal intensity on magnetic resonance (MR) imaging of tendons arising from the magic angle phenomenon is well recognized. This study aimed to evaluate the effect of varying the echo time (TE) upon tendon signal intensity, and to determine if a modified TE value produces acceptable T1 and proton density (PD) weighted images. Fresh bovine tendons were imaged in a 1.5 T MR scanner using spin echo (SE) T1 and PD weighted sequences and utilizing a number of different coils. For each set of sequences, the tendon was orientated at 55 degrees to the main magnetic field (B0) and imaged using constant TR and incremental TE values. Signal intensity was measured on images at each TR/TE value and compared with the signal intensities of tendons orientated at 0 degree to B0, obtained using minimum TE values. This experiment was repeated with a 1.0 T MR scanner and utilizing a spine coil. The Achilles tendon of a human volunteer was similarly imaged using a general purpose flex coil. For bovine and human tendons orientated at 55 degrees to B0, the signal intensities decreased exponentially with increasing TE. A critical TE value exceeding 37 ms, for each sequence, reduced the signal intensities to the levels obtained with the tendons orientated at 0 degree to B0, such that the magic angle phenomenon could be avoided. Although there was variability of the signal intensities with different coils, the critical TE value remained constant and the anatomical clarity was not degraded. The critical TE value was unaltered using two MR scanners of different field strengths.

Selective inhibitors of Candida albicans dihydrofolate reductase: activity and selectivity of 5-(arylthio)-2,4-diaminoquinazolines

The recent increase in fungal infections, especially among AIDS patients, has resulted in the need for more effective antifungal agents. In our search for such agents, we focused on developing compounds which inhibit fungal dihydrofolate reductase (DHFR). A series of 25 5-(arylthio)-2,4-diaminoquinazolines were synthesized as potentially selective inhibitors of Candida albicans DHFR. The majority of the compounds were potent inhibitors of C. albicans DHFR and much less active against human DHFR. High selectivity, as defined by the ratio of the I50 values for human and C. albicans DHFR, was achieved by compounds with bulky and rigid 4-substituents in the phenylthio moiety. For example, 5-[(4-morpholinophenyl)thio]-2,4-diaminoquinazoline displayed a selectivity ratio of 540 and was the most selective inhibitor synthesized to date. Substitution in the 2- or 3-position of the 5-phenylthio group provided only marginal selectivity. 6-Substituted-5-[(4-tert-butylphenyl)thio]-2,4-diaminoquinazolines showed potent activity against the C. albicans enzyme but were equally active against human DHFR. Most of the selective compounds were also good inhibitors of C. albicans cell growth, with minimum inhibitory concentration values as low as 0.05 microgram/ mL.

2,4-Diamino-5-benzylpyrimidines as antibacterial agents. 14. 2,3-Dihydro-1-(2,4-diamino-5-pyrimidyl)-1H-indenes as conformationally restricted analogues of trimethoprim

A conformationally restricted analogue of trimethoprim (1a) has been prepared by connecting the ortho position of the benzene ring to the methylene linkage with two methylene groups, thus forming a dihydroindene derivative (2b). The chemistry involved the condensation of barbituric acid with an indanone derivative, followed by a three-step conversion to a 2,4-diaminopyrimidine. The S isomer of 2b was found to have a minimum-energy conformation very similar to that of 1a when bound to Escherichia coli dihydrofolate reductase, in contrast to that of 1a in vertebrate DHFR. Theoretically such a derivative might have increased specificity and activity against the bacterial enzyme. Molecular modeling experiments suggested that the actual decreased activity was due to crowding in the enzyme, caused by the extra atoms needed to restrict the conformation.

2,4-Diamino-5-benzylpyrimidines and analogues as antibacterial agents. 11. Quinolylmethyl analogues with basic substituents conveying specificity

A series of nine 2,4-diamino-5-[6-( or 7-)quinolylmethyl]pyrimidines has been prepared by condensations of quinolinecarboxaldehydes with beta-anilinopropionitriles, followed by treatment with guanidine. All compounds has basic or methoxy substituents at the 2- or 4-positions of the quinoline ring. All of the 6-quinolylmethyl derivatives were highly inhibitory against Escherichia coli dihydrofolate reductase (DHFR), provided that an 8-substituent was present in the quinoline ring. Those compounds that had basic substituents in the 2-position of the quinoline ring were also highly specific for bacterial dihydrofolate DHFR, relative to a vertebrate counterpart. Protonation on the quinoline ring nitrogen is a possible cause of specificity.

The activity of alkyl phosphorylcholines and related derivatives against Leishmania donovani

Several alkyl phosphorylcholines and related derivatives were tested against Leishmania donovani amastigotes in mouse peritoneal macrophages in vitro and ED50 values were determined in the range of 1-12 microM. The three alkyl phosphorylcholines tested against L. donovani in BALB/c mice were active, an ED50 of 12.8 mg/kg/day X 5 was ascertained for one compound, but an alkyl phosphorylethanolamine was inactive.

SNR in optical velocimeters: effect of detection angle

Measurements of scattering power and SNR as a function of detection angle were carried out employing a differential heterodyne laser Doppler velocimeter (DLDV) and a white light fringe image velocimeter (WFIV). Particle diameters of 0.481 microm and 5.7 microm were employed for the DLDV and WFIV, respectively. In general, the measurements are in excellent agreement with calculations based on Mie theory.

SNR in optical velocimeters: effect of particle number density

Measurements of SNR as a function of number density (n) were carried out employing a Differential Heterodyne Laser Doppler Velocimeter (DLDV) and a White Light Fringe Image Velocimeter (WFIV). These two techniques made it possible to investigate separately the coherent and incoherent scattering modes, respectively. It was observed that with the WFIV the SNR is proportional to n for n values corresponding to less than one particle in the probe volume. The SNR remains constant for large n values. In the case of the DLDV the SNR was always found to be proportional to n when the coherence condition was satisfied. Consequently, it is concluded that the DLDV signal results entirely from coherent scattering, even when the number of particles in the probe volume is as low as 0.02 (the lower limit of the measurements).