Multidrug-Resistant Shigella sonnei Bacteremia among Persons Experiencing Homelessness, Vancouver, British Columbia, Canada

Increased invasive bloodstream infections caused by multidrug resistant Shigella sonnei were noted in Vancouver, British Columbia, Canada, during 2021-2023. Whole-genome sequencing revealed clonal transmission of genotype 3.6.1.1.2 (CipR.MSM5) among persons experiencing homelessness. Improvements in identifying Shigella species, expanding treatment options for multidrug resistant infections, and developing public health partnerships are needed.

Hippocampal cingulum white matter increases over time in young people at high genetic risk for bipolar disorder

BACKGROUND

Bipolar disorder (BD) is a strongly familial psychiatric disorder associated with white matter (WM) brain abnormalities. It is unclear whether such abnormalities are present in relatives without BD, and little is known about WM trajectories in those at increased genetic risk.

METHODS

Diffusion magnetic resonance imaging (dMRI) data were acquired at baseline and after two years in 91 unaffected individuals with a first-degree relative with bipolar disorder (HR), and 85 individuals with no family history of mental illness (CON). All participants were aged between 12 and 30 years at baseline. We examined longitudinal change in Fractional Anisotropy (FA) using tract-based spatial statistics (TBSS).

RESULTS

Compared to the CON group, HR participants showed a significant increase in FA in the right cingulum (hippocampus) (CGH) over a two-year period (p < .05, FDR corrected). This effect was more pronounced in HR individuals without a lifetime diagnosis of a mood disorder than those with a mood disorder.

LIMITATIONS

While our study is well powered to achieve the primary objectives, our sub-group analyses were under powered.

CONCLUSIONS

In one of the very few longitudinal neuroimaging studies of young people at high risk for BD, this study reports novel evidence of atypical white matter development in HR individuals in a key cortico-limbic tract involved in emotion regulation. Our findings also suggest that this different white matter developmental trajectory may be stronger in HR individuals without affective psychopathology. As such, increases in FA in the right CGH of HR participants may be a biomarker of resilience to mood disorders.

Accelerated cortical thinning and volume reduction over time in young people at high genetic risk for bipolar disorder

BACKGROUND

Bipolar disorder (BD) is a familial psychiatric disorder associated with frontotemporal and subcortical brain abnormalities. It is unclear whether such abnormalities are present in relatives without BD, and little is known about structural brain trajectories in those at risk.

METHOD

Neuroimaging was conducted at baseline and at 2-year follow-up interval in 90 high-risk individuals with a first-degree BD relative (HR), and 56 participants with no family history of mental illness who could have non-BD diagnoses. All 146 subjects were aged 12-30 years at baseline. We examined longitudinal change in gray and white matter volume, cortical thickness, and surface area in the frontotemporal cortex and subcortical regions.

RESULTS

Compared to controls, HR participants showed accelerated cortical thinning and volume reduction in right lateralised frontal regions, including the inferior frontal gyrus, lateral orbitofrontal cortex, frontal pole and rostral middle frontal gyrus. Independent of time, the HR group had greater cortical thickness in the left caudal anterior cingulate cortex, larger volume in the right medial orbitofrontal cortex and greater area of right accumbens, compared to controls. This pattern was evident even in those without the new onset of psychopathology during the inter-scan interval.

CONCLUSIONS

This study suggests that differences previously observed in BD are developing prior to the onset of the disorder. The pattern of pathological acceleration of cortical thinning is likely consistent with a disturbance of molecular mechanisms responsible for normal cortical thinning. We also demonstrate that neuroanatomical differences in HR individuals may be progressive in some regions and stable in others.

The second-hand effects of antibiotics: communicating the public health risks of drug resistance

Antimicrobial resistance (AMR) poses a threat to modern medicine, but there are challenges in communicating its urgency and scope and potential solutions to this growing problem. It is recognized that AMR has a 'language problem' and the way in which healthcare professionals communicate about AMR may not always resonate with patients. Many patients are unaware that antibiotics can have detrimental effects to those beyond the recipient, due to transmission of drug-resistant organisms. The overestimation of benefits and underestimation of risks helps to fuel demand for antibiotic use in situations where they may be of little or no benefit. To better communicate risks, clinicians may borrow the term 'second-hand' from efforts to reduce smoking cessation. We present several examples where antibiotics themselves have second-hand effects beyond the individual recipient in hospitals, long-term care homes and the community. Incorporation of the concept of the second-hand effects of antibiotics into patient counselling, mass messaging and future research may help facilitate a more balanced discussion about the benefits and risks of antibiotic use in order to use these agents more appropriately.

Family medicine vocational training and career satisfaction in Hong Kong

BACKGROUND

Postgraduate vocational training in family medicine (FM) is essential for physicians to build capacity and develop quality primary care. Inadequate standards in training and curriculum development can contribute to poor recruitment and retention of doctors in primary care. This study aimed to investigate: 1) the satisfaction level of doctors regarding vocational training in family medicine and associated demographics; and 2) the satisfaction level of doctors regarding their family medicine career and associated factors.

METHOD

This is a cross sectional study of all family medicine physicians across all government-funded primary care clinics (GOPCs). The study questionnaire consisted of items from a standardized and validated physician survey named the Physician Worklife Survey (PWS) (Konrad et al., Med Care, 1999). We selected three scales (7 items) relating to global job satisfaction, global career satisfaction and global specialty (family medicine) satisfaction with additional items on training and demographics. All significant variables in bivariate analyses were further examined using stepwise logistic regression.

RESULTS

Out of 424 eligible family medicine physicians, 368 physicians successfully completed the questionnaire. The response rate was 86.8%. Most participants were male (52.6%), were aged between 35 and 44 years (55.5%), were FM specialists (42.4%), graduated locally (86.2%), and had postgraduate qualifications. Eighty-two percent (82%) of participants were satisfied with their training. Having autonomy and protected time for training were associated with satisfaction with FM training. Satisfaction with family medicine as a career was correlated with physicians' satisfaction with their current job. Doctors who did not enroll in training (p < 0.001) and physicians who were older (p = 0.023) were significantly less satisfied. Stepwise multivariate regression showed that doctors who subjectively believed their training as "broad and in depth' had higher career satisfaction (p < 0.001).

CONCLUSION

Overall, the satisfaction level of physicians on current family medicine training in Hong Kong was high. Having autonomy and protected time for training is associated with higher training satisfaction levels. Perceiving FM training as "broad and in-depth" is associated with higher family medicine career satisfaction.

Annual report on influenza viruses received and tested by the Melbourne WHO Collaborating Centre for Reference and Research on Influenza in 2016

As part of its role in the World Health Organization’s (WHO) Global Influenza Surveillance and Response System (GISRS), the WHO Collaborating Centre for Reference and Research on Influenza in Melbourne received a total of 4,247 human influenza positive samples during 2016. Viruses were analysed for their antigenic, genetic and antiviral susceptibility properties and also propagated in qualified cells and hens eggs for potential seasonal influenza vaccine virus candidates. In 2016, influenza A(H3) viruses predominated over influenza A(H1)pdm09 and B viruses, accounting for a total of 51% of all viruses analysed. The vast majority of A(H1)pdm09, A(H3) and influenza B viruses analysed at the Centre were found to be antigenically similar to the respective WHO recommended vaccine strains for the Southern Hemisphere in 2016. However, phylogenetic analysis of a selection of viruses indicated that the majority of circulating A(H3) viruses had undergone some genetic drift relative to the WHO recommended strain for 2016. Of more than 3,000 samples tested for resistance to the neuraminidase inhibitors oseltamivir and zanamivir, six A(H1)pdm09 viruses and two B/Victoria lineage viruses showed highly reduced inhibition to oseltamivir.

Structural dysconnectivity of key cognitive and emotional hubs in young people at high genetic risk for bipolar disorder

Emerging evidence suggests that psychiatric disorders are associated with disturbances in structural brain networks. Little is known, however, about brain networks in those at high risk (HR) of bipolar disorder (BD), with such disturbances carrying substantial predictive and etiological value. Whole-brain tractography was performed on diffusion-weighted images acquired from 84 unaffected HR individuals with at least one first-degree relative with BD, 38 young patients with BD and 96 matched controls (CNs) with no family history of mental illness. We studied structural connectivity differences between these groups, with a focus on highly connected hubs and networks involving emotional centres. HR participants showed lower structural connectivity in two lateralised sub-networks centred on bilateral inferior frontal gyri and left insular cortex, as well as increased connectivity in a right lateralised limbic sub-network compared with CN subjects. BD was associated with weaker connectivity in a small right-sided sub-network involving connections between fronto-temporal and temporal areas. Although these sub-networks preferentially involved structural hubs, the integrity of the highly connected structural backbone was preserved in both groups. Weaker structural brain networks involving key emotional centres occur in young people at genetic risk of BD and those with established BD. In contrast to other psychiatric disorders such as schizophrenia, the structural core of the brain remains intact, despite the local involvement of network hubs. These results add to our understanding of the neurobiological correlates of BD and provide predictions for outcomes in young people at high genetic risk for BD.

Oxaliplatin versus Mitomycin C for HIPEC in colorectal cancer peritoneal carcinomatosis

OBJECTIVE

Compare long-term outcomes in colorectal cancer (CRC) patients with peritoneal carcinomatosis (PC) treated with peritonectomy/HIPEC using oxaliplatin versus MMC.

BACKGROUND

Peritonectomy and heated intraperitoneal chemotherapy (HIPEC) greatly improves patient survival in CRC PC. This procedure is not uniform across centres and the optimal choice of HIPEC chemotherapeutic is unclear. Oxaliplatin and Mitomycin C (MMC) are the most commonly used agents and comparative studies have reported varying results.

METHOD

201 patients were retrospectively selected from the St George Hospital database, all of which had undergone peritonectomy/HIPEC for CRC PC. Oxaliplatin and MMC were used in 106 and 96 patients, respectively. Each patient's baseline characteristics, operative details, choice of chemotherapeutic agent and survival were noted.

RESULTS

The two groups did not differ significantly at baseline. Patients receiving oxaliplatin had significantly greater unadjusted median survival compared to MMC (56.0 ± 8.1 vs. 29.0 ± 3.4 months) which translated into a hazards ratio of 0.59 (95% CI 0.37-0.91, p = 0.017). Subgroup analysis further confirmed an advantage with oxaliplatin in females, moderate-well differentiated tumours, tumours without signet ring pathology and PCI 10-15.

CONCLUSION

Our study suggests oxaliplatin offers a survival advantage over MMC when used for HIPEC in CRC PC. Further studies to understand its efficacy, complications and ideal preparation are required. A Phase III randomised control trial comparing oxaliplatin and MMC would enhance decision-making.

High risk features of primary colorectal carcinomas which subsequently undergo peritonectomy

OBJECTIVE

Determine what portion of colorectal cancer (CRC) patients with peritoneal metastases (PM) undergoing peritonectomy would have been identified/treated if second-look surgery protocol existed for high-risk primary tumours.

BACKGROUND

The prognosis of CRC PM greatly improves following peritonectomy/HIPEC. Survival remains dependent upon stage of PM and there is some knowledge of high-risk factors for its development. Subsequently, there is interest in routine second-look laparotomy to follow-up high-risk CRC patients so to 'prevent' PM.

METHODS

Patients were retrospectively selected from the St George database, all of whom had had PM recurrence after primary CRC resection thus underwent peritonectomy/HIPEC. Each patient's primary tumour pathology was obtained with incidence of high-risk stage (T4), macroscopic (peritoneal involvement, ovarian metastases, perforated primary) and microscopic (mucinous, signet ring) features noted.

RESULTS

125 patients were included. At primary diagnosis, 34.4%, 46.4% and 19.2% were of T3, T4a and T4b stage. Primary tumour macroscopic features included 41.1%, 12.6% and 23.7% with synchronous peritoneal involvement, perforated primary and ovarian metastases. Primary tumour microscopic features included 8.1%, 44.0% and 5.6% with signet ring, mucinous and both pathologies. Individually T4 status, macroscopic and microscopic features would have identified 65.6%, 56.8% and 46.5% of patients. Any high-risk factor would have identified 85.6%.

CONCLUSION

Our study suggests that T4 stage, high-risk macroscopic and high-risk microscopic features at time of primary diagnosis identifies the majority of CRC patients who later develop PM. This provides support for a selective second-look protocol in such patients to enable early identification and, potentially, 'prevention' of CRC PM.

Healthcare workers' decision-making about transmission-based infection control precautions is improved by a guidance summary card

BACKGROUND

Transmission-based precautions (TBPs) are infection control measures designed to interrupt pathogen transmission. Success relies on early recognition of patients with potentially infectious syndromes, then the implementation of appropriate TBPs. We are aware of no literature evaluating interventions to facilitate healthcare workers (HCWs) in implementing TBPs.

AIM

To evaluate the impact of a TBP guidance summary card on HCWs' decision-making about the appropriate implementation of TBPs.

METHODS

A prospective audit was carried out to assess HCWs' ability to make decisions about TBP implementation. Following the first audit phase, staff were issued with a guidance card summarizing local TBP guidelines, identifying and addressing relevant TBP measures for infectious syndromes and specific organisms. The audit cycle was then completed to assess the impact of this intervention.

FINDINGS

Baseline knowledge of appropriate TBP measures was low. Provision of a TBP summary card was significantly associated with the ability of staff carrying the card to correctly decide what TBPs are required in a variety of clinical situations, including Clostridium difficile infection [N = 107; odds ratio (OR): 27.0; 95% confidence interval (CI): 8.37-86.8; P < 0.0001], norovirus diarrhoea and vomiting (N = 107; OR: 94.3, 95% CI: 25.0-356; P < 0.0001), influenza-like illness (N = 107; OR: 85.2; 95% CI: 4.94-1470; P < 0.0001) and the difference between surgical and FFP3 masks (N = 107; OR: 412; 95% CI: 23.4-7246; P < 0.0001).

CONCLUSION

There is a lack of knowledge about TBP among HCWs. This study demonstrates how an inexpensive TBP summary card is an effective mechanism for improving (i) point-of-care access to TBP guidance and (ii) decision-making about appropriate implementation of TBP.

A novel hydrogel-collagen composite improves functionality of an injectable extracellular matrix

Cellular transplantation is now closer to becoming a practical clinical strategy to repair, regenerate or restore the function of skin, muscle, nerves and pancreatic islets. In this study we sought to develop a simple injectable collagen matrix that would preserve the normal cellular organization of skin cells. Three different scaffolds were created and compared: collagen-glycosaminoglycan (GAG) scaffolds, crosslinked collagen-GAG scaffolds without polyvinyl alcohol (PVA) and crosslinked collagen-GAG scaffolds containing PVA hydrogel. Importantly, all scaffolds were found to be non-cytotoxic. PVA-containing gels exhibited a higher tensile strength (P<0.05), faster fibril formation (P<0.001) and reduced collagenase digestion (P<0.01) compared with other gels. Free floating fibroblast-populated, PVA-borate scaffolds resisted contraction over a 10 day period (P<0.001). The fibroblast-populated scaffolds containing PVA demonstrated a 3-fold reduction in cellularity over 10 days compared with the control gels (P<0.001). Multicellular skin substitutes containing PVA-borate networks display a linear cellular organization, reduced cellularity and the formation of a keratinized epidermis that resembles normal skin. In conclusion, these data underscore the multifunctionality of a simple PVA-borate-collagen matrix as an injectable composite for tissue engineering or cell transplantation.

Spontaneous four-wave mixing of de Broglie waves: beyond optics

We investigate the atom-optical analog of degenerate four-wave mixing by colliding two Bose-Einstein condensates of metastable helium. The momentum distribution of the scattered atoms is measured in three dimensions. A simple analogy with photon phase matching conditions suggests a spherical final distribution. We find, however, that it is an ellipsoid with radii smaller than the initial collision momenta. Numerical and analytical calculations agree with this and reveal the interplay between many-body effects, mean-field interaction, and the anisotropy of the source condensate.

A comparison of patient adherence and preference of packaging method for oral anticancer agents using conventional pill bottles versus daily pill boxes

Adherence to medications is an important issue in oncology due to the increasing number of anticancer agents, such as targeted therapies, formulated for oral dosing. A prospective, crossover design was utilized in which patients on capecitabine were randomly assigned to one of two packaging methods for one cycle, and then switched over to the alternate packaging method in the subsequent cycle. Twenty-five patients were accrued to this study. Adherence rates were similar when using the daily pill boxes (17/21 = 81%) and when using the conventional pill bottles (18/21 = 86%). However, more patients were satisfied with the daily pill boxes (61% versus 11%, P = 0.027), preferred the daily pill boxes (61% versus 17%, P = 0.061), and thought the daily pill boxes were more helpful in reminding them to take their medications (50% versus 11%, P = 0.070). In conclusion, this small pilot study did not demonstrate that the use of daily pill boxes improved patient adherence with capecitabine, but patient satisfaction and preference for this packaging method were greater than for the conventional pill bottles. Further exploration of this intervention in a larger study is warranted.

The antennal system and cockroach evasive behavior. I. Roles for visual and mechanosensory cues in the response

Cockroaches escape from predators by turning and then running. This behavior can be elicited when stimuli deflect one of the rostrally located and highly mobile antennae. We analyzed the behavior of cockroaches, under free-ranging conditions with videography or tethered in a motion tracking system, to determine (1) how antennal positional dynamics influence escape turning, and (2) if visual cues have any influence on antennal mediated escape. The spatial orientation of the long antennal flagellum at the time of tactile stimulation affected the direction of resultant escape turns. However, the sign of flagellar displacement caused by touch stimuli, whether it was deflected medially or laterally for example, did not affect the directionality of turns. Responsiveness to touch stimuli, and escape turn performance, were not altered by blocking vision. However, because cockroaches first orient an antenna toward stimuli entering the peripheral visual field, turn direction can be indirectly influenced by visual input. Finally, when vision was blocked, the run phase of escape responses displayed reduced average velocities and distances traveled. Our results suggest that tactile and visual influences are integrated with previously known wind-sensory mechanisms to achieve multisensory control of the full escape response.

Behavioral profile of Alzheimer's disease in Chinese elderly--a validation study of the Chinese version of the Alzheimer's disease behavioral pathology rating scale

OBJECTIVES

This study aims to examine the psychometric properties of the Chinese version of the Alzheimer's disease behavioral pathology rating scale (CBehave-AD) and the behavioral profile of Chinese patients with AD.

METHODS

Seventy-one subjects with NINCDS-ADRDA diagnosis of probable and possible AD were assessed for validation of the CBehave-AD. A behavioral symptom frequency checklist, the Chinese version of the Blessed Roth dementia scale (CDS) and the Cantonese version of the Mini-Mental State Examination (CMMSE) were used for comparison. An extended sample of 120 AD patients was then evaluated with the CBehave-AD.

RESULTS

High correlations between the CBehave-AD and checklist scores were found (paranoid and delusional ideation, hallucinations, activity disturbances, aggressiveness and diurnal rhythm disturbances). The scale also demonstrated satisfactory inter-rater and test-retest reliabilities. The mean (SD) CMMSE score of the 120 patients was 9.4 (7.1). Among them, 32% have delusions, 15% had hallucinations, 54% had activity disturbances, 61% had aggressive behavior, 44% had sleep disturbance, 24% had affective disturbances, 19% had anxiety and phobias. Delusional ideation was significantly associated with hallucinations, aggressiveness, and affective disturbances. Diurnal rhythm disturbances were associated with activity disturbances and aggressiveness. CBehave-AD total scores were not significantly correlated with severity of AD, but individual symptom categories showed different pattern of correlation. Delusions, hallucinations, anxiety and phobias were significantly correlated with dementia staging.

CONCLUSION

The findings suggest that the CBehave-AD is a valid assessment tool for behavioral disturbances in patients with AD. Variable associations between different symptom categories and dementia staging suggest a need for further exploration of the complex interactions between behavioral and cognitive disturbances in dementia.

Hydraulic fluids and jet engine oil: pyrolysis and aircraft air quality

Incidents of smoke in aircraft cabins often result from jet engine oil and/or hydraulic fluid that leaks into ventilation air, which can be subjected to temperatures that exceed 500 degrees C. Exposed flight-crew members have reported symptoms, including dizziness, nausea, disorientation, blurred vision, and tingling in the legs and arms. In this study, the authors investigated pyrolysis products of one jet engine oil and two hydraulic fluids at 525 degrees C. Engine oil was an important source of carbon monoxide. Volatile agents and organophosphate constituents were released from all the agents tested; however, the neurotoxin trimethyl propane phosphate was not found. The authors hypothesized that localized condensation of pyrolysis products in ventilation ducts, followed by mobilization when cabin heat demand was high, accounted for mid-flight incidents. The authors recommended that carbon monoxide data be logged continuously to capture levels during future incidents.

The measurement of volatile constituents in Foray 48B, an insecticide prepared from Bacillus thuringiensis var. kurstaki

Foray 48B, an insecticide prepared from Bacillus thuringiensis var. kurstaki (Btk), has been used for many years to combat infestations of Gypsy moths. Foray 48B also contains a large number of 'inert ingredients' which are not disclosed by the manufacturer. Gypsy moths usually enter the country through marine- and airports in close proximity to urban areas, which consequently need to be sprayed. The population affected often demands more detailed information than what is available including the potential presence of volatile organic agents which could be released during spraying, posing a potential health hazard. Four different methods were investigated using GC/mass spectrometry regarding their ability to capture volatile agents associated with Foray 48B. It was found that solid phase micro-extraction was most efficient in capturing volatile agents from the head-space of Foray 48B. Separate trials using 95:5% ethanol/isopropanol mixture and toluene in an impinger configuration were much less efficient. Standard techniques using activated charcoal tubes in the laboratory setting as well as in a field trial did not capture any compounds. It was concluded that the volatile agents associated with Foray 48B did not appear to constitute a significant health hazard and no one agent was a likely candidate to serve as a tracer for Foray 48B exposure.

Assessing the binding and endocytosis activity of cellular receptors using GFP-ligand fusions

We have developed a simple scheme for characterizing ligand-receptor binding and post-binding activity on living cells. Our approach makes use of green fluorescent protein (GFP) as an auto-fluorescent tag to label protein ligands. We have constructed GFP-tagged ligands that can be expressed in bacteria as soluble fusion proteins. A cell-binding assay using fluorescence-activated cell sorting (FACS) demonstrates that GFP-tagged proteins retain their wild-type receptor-binding specificity. Using this assay, we measure ligand binding on unfixed cells and demonstrate receptor specificity using specific competitors. To determine the ability of receptor targets to internalize, we developed a second FACS-based assay to detect the rate and percentage of internalized ligand in living cells. Noninternalizing control ligands and fluorescence microscopy of treated cells confirm that our assay is reliable for determining receptor internalization activity.

Exposure to dust, resin acids, and monoterpenes in softwood lumber mills

A study to assess exposure to potential respiratory hazards in a large lumber mill processing spruce (Picea engelmannii and glauca), pine (Pinus contorta), and fir (Abies lasiocarpa) used a random sampling strategy to assess exposures for all jobs in the sawmill, planer mills, and yard. Personal samples for inhalable particulate were collected to measure exposure to dust and resin acids (abietic acid and pimaric acid). To estimate wood dust exposure, rather than overall dust, the resin acid content within dust was used in combination with observations of job tasks and proximity to dust sources. Passive dosimeters were used to measure exposure to alpha-pinene, beta-pinene, delta3-carene, and other unidentified wood volatiles suspected to be monoterpenes. The GM of the 220 inhalable particulate samples was 1.0 mg/m3 whereas the mean abietic acid, pimaric acid, and estimated wood dust levels were 7.2 microg/m3, 0.6 microg/m3, and 0.5 mg/m3, respectively. The GMs of the 222 monoterpene samples were 0.1 mg/m3 for alpha-pinene, 0.3 mg/m3 for beta-pinene, 0.1 mg/m3 for delta3-carene, and 0.5 mg/m3 for the unidentified wood volatiles. Monoterpene exposures were much lower than those observed in other studies conducted in Sweden and Finland. The results of this exposure assessment highlight the importance of considering the content of airborne particulates in lumber mills as well as potential exposure to wood chemicals.

Temporal and spatial expression of Hoxa-2 during murine palatogenesis

1. Mice homozygous for a targeted mutation of the Hoxa-2 gene are born with a bilateral cleft of the secondary palate associated with multiple head and cranial anomalies and these animals die within 24 hr of birth (Gendron-Maguire et al., 1993; Rijli et al., 1993; Mallo and Gridley, 1996). We have determined the spatial and temporal expression of the Hoxa-2 homeobox protein in the developing mouse palate at embryonic stages E12, E13, E13.5, E14, E14.5, and E15. 2. Hoxa-2 is expressed in the mesenchyme and epithelial cells of the palate at E12, but is progressively restricted to the tips of the growing palatal shelves at E13. 3. By the E13.5 stage of development, Hoxa-2 protein was found to be expressed throughout the palatal shelf. These observations correlate with palatal shelf orientation and Hoxa-2 protein may play a direct or indirect role in guiding the palatal shelves vertically along side the tongue, starting with the tips of the palatal shelves at E13, followed by the entire palatal shelf at E13.5. 4. As development progresses to E14, the stage at which shelf elevation occurs, Hoxa-2 protein is downregulated in the palatal mesenchyme but remains in the medial edge epithelium. Expression of Hoxa-2 continues in the medial edge epithelium until the fusion of opposing palatal shelves. 5. By the E15 stage of development, Hoxa-2 is downregulated in the palate and expression is localized in the nasal and oral epithelia. 6. In an animal model of phenytoin-induced cleft palate, we report that Hoxa-2 mRNA and protein expression were significantly decreased, implicating a possible functional role of the Hoxa-2 gene in the development of phenytoin-induced cleft palate. 7. A recent report by Barrow and Capecchi (1999), has illustrated the importance of tongue posture during palatal shelf closure in Hoxa-2 mutant mice. This along with our new findings of the expression of the Hoxa-2 protein during palatogenesis has shed some light on the putative role of this gene in palate development.

Comparison of the constituents of two jet engine lubricating oils and their volatile pyrolytic degradation products

Leaking oil seals in jet engines, at locations prior to the compressor stage, can be a cause of smoke in the cabins of BAe-146 aircraft. Compressed combustion air is bled off to pressurize the cabin and to provide a source of fresh air. Bleed air is diverted from a location just prior to the combustion chamber at a temperature around 500 degrees C. To prevent oil breakdown products from entering the cabin air, catalytic converters have been used to clean the air. During an oil seal failure this device becomes overloaded and smoke is observed in the cabin. Some aircraft companies have removed the catalytic converters and claim an improvement in air quality. During an oil seal failure, however, the flight crew is potentially exposed to the thermal breakdown products of the engine oils. Because very little is known regarding the thermal breakdown products of jet engine lubrication oils, two commercially available oils were investigated under laboratory conditions at 525 degrees C to measure the release of CO, CO2,NO2, and HCN as well as volatiles which were analyzed using GC-Mass spectrometry in an attempt to see if the neurotoxic agents tricresyl phosphates (TCPs) and trimethyl propane phosphate (TMPP) would be present or formed. TMPP was not found in these experiments. Some CO2 was generated along with CO which reached levels in excess of 100 ppm. HCN and NO2 were not detected. GC compositions of the two bulk oils and their breakdown products were almost identical. The presence of TCPs was confirmed in the bulk oils and in the volatiles. Localized condensation in the ventilation ducts and filters in the air conditioning packs are likely the reason why the presence of TCPs has not been demonstrated in cabin air. It was recommended that this needed to be verified in aircraft.

Determinants of exposure to inhalable particulate, wood dust, resin acids, and monoterpenes in a lumber mill environment

In a lumber mill in the northern inland region of British Columbia, Canada, we measured inhalable particulate, resin acid, and monoterpene exposures, and estimated wood dust exposures. Potential determinants of exposure were documented concurrently, including weather conditions, tree species, wood conditions, jobs, tasks, equipment used, and certain control measures. Over 220 personal samples were taken for each contaminant. Geometric mean concentrations were 0.98 mg/m3 for inhalable particulate, 0.49 mg/m3 for estimated wood dust, 8.04 micrograms/m3 for total resin acids, and 1.11 mg/m3 for total monoterpenes. Multiple regression models for all contaminants indicated that spruce and pine produced higher exposures than alpine fir or mixed tree species, cleaning up sawdust increased exposures, and personnel enclosure was an effective means of reducing exposures. Sawing wood in the primary breakdown areas of the mill was the main contributor to monoterpene exposures, so exposures were highest for the barker operator, the head rig operator, the canter operator, the board edgers, and a roving utility worker in the sawmill, and lowest in the planer mills (after kiln drying of the lumber) and yard. Cleaning up sawdust, planing kiln-dried lumber, and driving mobile equipment in the yard substantially increased exposures to both inhalable particulate and estimated wood dust. Jobs at the front end of the sawmill where primary breakdown of the logs takes place had lower exposures. Resin acid exposures followed a similar pattern, except that yard driving jobs did not increase exposures.

A gene essential to brain growth and development maps to the distal arm of rat chromosome 12

A recently discovered, spontaneous, autosomal recessive mutation in rats, flathead (fh), results in greatly reduced brain growth beginning in late fetal development. In this study we have mapped the fh mutation by determining the pattern of segregation of polymorphic microsatellite markers with respect to fh in 51 affected F2 offspring from a single interstrain intercross. Two markers on chromosome 12, D12Rat80 and D12Mgh6, cosegregated with the fh mutation in all 51 affected animals. The distribution of six additional markers in 40 informative meioses further localizes fh approximately 2 cM teleomeric to nos1. There are no known mutations in homologous regions of either mouse or human genomes that result in deficits in late neurodevelopment similar to that observed in fh/fh animals. The unique phenotype of fh/fh animals and the location of fh suggests the presence of a novel gene essential to normal brain development on the distal end of rat chromosome 12.

Analysis of nicotine and cotinine in the hair of hospitality workers exposed to environmental tobacco smoke

The purpose of this study was to determine if hair nicotine and cotinine levels reflect relative exposure to environmental tobacco smoke (ETS) in subjects who worked in the hospitality industry, where public smoking was permitted. Hair samples from 26 subjects were analyzed by gas chromatograph/mass spectrometry techniques for nicotine and cotinine. An exposure gradient was shown for nicotine but not cotinine. Among nonsmokers, those working in bars where there are no public smoking restrictions had the highest hair nicotine levels, which were close to levels found in smokers. Nicotine measured in hair is useful as a biological marker for exposure to ETS from multiple sources. Bar workers in particular are exposed to high levels of ETS, which may adversely affect the health of nonsmokers.

Suicide attempt due to metoclopramide-induced akathisia

Akathisia as a side-effect of metoclopramide has received increasing attention in consultation-liaison psychiatry in recent years. A case of metoclopramide-induced akathisia resulting in a suicide attempt is reported in order to highlight the suffering of such patients and the factors that lead to misdiagnosis.

Multifaceted treatment of congenital nystagmus: a report of 6 cases

Patients with congenital nystagmus (CN) often have associated conditions (e.g., strabismus, high astigmatism, and binocular inefficiency) that also impair visual acuity. Unfortunately, individually used techniques directed at reducing nystagmus have generally produced only slight increases in Snellen acuity. We present case reports of six patients with nystagmus seen in our clinic (University of Houston, College of Optometry) to illustrate the use of problem-specific management to improve visual acuity and/or binocular function. The results suggest that a comprehensive management strategy should include treatment of all associated conditions as well as therapy to improve the characteristics of the nystagmus wave form.

Reversal of hepatic encephalopathy and alteration in amino acid profiles after blocking a surgical splenorenal shunt by interventional radiological techniques

Portal-systemic shunts are effective in preventing haemorrhage from varices in portal hypertension, but at the price of hepatic encephalopathy. We describe the blockage of a splenorenal shunt using interventional radiology, in a patient with incapacitating chronic encephalopathy. The procedure successfully reversed encephalopathy, without haemodynamic disturbances or haemorrhage from recurrent varices and was associated with a return of the plasma amino acid profile towards normal, with a reduction in aromatic amino acids and an increase in branch chain amino acids. This observation supports the hypothesis that changes in plasma amino acid profiles in patients with portal-systemic shunting are due to the diversion of portal blood rather than the underlying chronic liver disease.

Diet, growth and cultural food habits in Chinese-American infants

This study was composed of one hundred Chinese-American mothers and infants in the Chinatown district of San Francisco. The mothers were interviewed with regard to infants' dietary intakes and past dietary patterns, infant health, maternal pre-natal history and diet, cultural habits, and socio-economic status. Infants' growth patterns were recorded and compared to those of American and Chinese babies. Their growth patterns were noted to be dissimilar to both American and Chinese growth patterns, but to be very similar to infant growth patterns in underdeveloped countries. The cultural influences on the dietary intakes were commented upon.