The Kety-Schmidt technique for quantitative perfusion and oxygen metabolism measurements in the MR imaging environment.

SUMMARY: The Kety-Schmidt technique provides quantitative measurement of whole-brain CBF. CBF is measured as the area between the arterial and venous washout curves of a diffusible tracer. Oxygen extraction and metabolism may be calculated from arterial and venous samples. In this report, we present a method for performing these measurements in an MR imaging environment. This technique could be useful for validation of MR imaging methods of hemodynamic and metabolic measurements in humans.

Effects of rainfall, host demography, and musth on strongyle fecal egg counts in African elephants (Loxodonta africana) in Namibia.

Wild African elephants (Loxodonta africana) are commonly infected with intestinal strongyle parasites. Our objective was to determine baseline fecal strongyle egg counts for elephants in the northeast region of Etosha National Park, Namibia and determine if these numbers were affected by annual rainfall, elephant demography (age of individuals and composition of groups), and hormonal state of males. We found that matriarchal family group members have significantly higher fecal egg counts than male elephants (bulls). Among family group members, strongyle egg counts increased with age, whereas among bulls, strongyle egg counts decreased with age. Years of higher rainfall were correlated with decreased numbers of strongyle eggs among bulls. Finally, bulls were not affected by their physiologic (hormonal) status (musth vs. nonmusth). These results suggest that infection by strongyle parasites in Namibian African elephants is a dynamic process affected by intrinsic and extrinsic factors including host demography and rainfall.

Actinic cheilitis in dental practice.

Actinic cheilitis is a potentially premalignant condition involving predominantly the vermilion of the lower lip. The aim of the current paper was to review the clinical presentation of actinic cheilitis and demonstrate the development of management plans using a series of cases. These are designed to provide immediate treatment where required but also to address the medium and long-term requirements of the patient. The authors suggest that the clinical examination of lips and the assessment of actinic cheilitis and other lip pathology become a regular part of the routine soft tissue examination undertaken as a part of the periodic examination of dental patients. Early recognition of actinic cheilitis can allow the development of strategies for individual patients that prevent progression. These are based on past sun exposure, future lifestyle changes and the daily use of emollient sunscreens, broad-brimmed hats and avoidance of sun exposure during the middle of the day. This is a service that is not undertaken as a matter of routine in general medical practice as patients are not seen with the regularity of dental patients and generally not under the ideal examination conditions available in the dental surgery.

Reflection across plant cell boundaries in confocal laser scanning microscopy.

The fluorescence patterns of proteins tagged with the green fluorescent protein (GFP) and its derivatives are routinely used in conjunction with confocal laser scanning microscopy to identify their sub-cellular localization in plant cells. GFP-tagged proteins localized to plasmodesmata, the intercellular junctions of plants, are often identified by single or paired punctate labelling across the cell wall. The observation of paired puncta, or 'doublets', across cell boundaries in tissues that have been transformed through biolistic bombardment is unexpected if there is no intercellular movement of the GFP-tagged protein, since bombardment usually leads to the transformation of single, isolated cells. We expressed a putative plasmodesmal protein tagged with GFP by bombarding Allium porrum epidermal cells and assessed the nature of the doublets observed at the cell boundaries. Doublets were formed when fluorescent spots were abutting a cell boundary and were only observable at certain focal planes. Fluorescence emitted from the half of a doublet lying outside the transformed cells was polarized. Optical simulations performed using finite-difference time-domain computations showed a dramatic distortion of the confocal microscope's point spread function when imaging voxels close to the plant cell wall due to refractive index differences between the wall and the cytosol. Consequently, axially and radially out-of-focus light could be detected. A model of this phenomenon suggests how a doublet may form when imaging only a single real fluorescent body in the vicinity of a plant cell wall using confocal microscopy. We suggest, therefore, that the appearance of doublets across cell boundaries is insufficient evidence for plasmodesmal localization due to the effects of the cell wall on the reflection and scattering of light.

Long-term engraftment following transplantation of pig pancreatic primordia into non-immunosuppressed diabetic rhesus macaques.

BACKGROUND: Transplantation therapy for human diabetes is limited by a shortage of donor organs, and transplant function diminished over time by cell death and limited potential for expansion of beta cells in pancreas or islets. Outcomes are complicated by immunosuppression. A way to overcome supply and expansion problems is to xenotransplant embryonic tissue. Previously, we have shown that beta cells originating from embryonic day (E) 28 (E28) pig pancreatic primordia transplanted into the mesentery of streptozotocin (STZ)-diabetic (type 1) Lewis rats or Zucker Diabetic Fatty (ZDF) diabetic (type 2) rats engraft and normalize glucose tolerance without the need for host immune-suppression. METHODS: In this study, we transplant E28 pig pancreatic primordia in the mesentery of STZ-diabetic rhesus macaques. RESULTS: Long-term engraftment of pig beta cells within liver, pancreas and mesenteric lymph nodes post-transplantation of E28 pig pancreatic primordia into STZ-diabetic rhesus macaques is demonstrated by electron microscopy, positive immune-histochemistry for insulin, and positive RT-PCR and in situ hybridization for porcine proinsulin mRNA. Insulin requirements were reduced in one macaque followed over 22 months post-transplantation and porcine insulin detected in plasma using sequential affinity chromatography, HPLC and mass spectrometry. Of potential importance for application of this transplantation technology to treatment of diabetes in humans and confirmatory of our previous findings in Lewis and ZDF rats, no host immunosuppression is required. CONCLUSIONS: Under selected circumstances, pancreatic primordia elicit a muted immune response relative to more differentiated tissue, such that engraftment occurs in non-immunosuppressed hosts. Our findings that pig pancreatic primordia engraft long-term in non-immunosuppressed STZ-diabetic rhesus macaques establishes the potential for their use in human diabetics.

Late Season Occurrence of Soybean Rust Caused by Phakopsora pachyrhizi on Soybean in Illinois.

Soybean rust, first reported in the continental United States in Louisiana in 2004 (2), is one of the most important foliar diseases of soybean worldwide. On 10 October 2006, 20 soybean leaflets from 20 plants at physiological maturity were arbitrarily collected in research plots near Glendale, IL at the University of Illinois Dixon Springs Agricultural Center in Pope County and sent by overnight courier. On 11 October, leaflets were examined with a dissecting microscope at the Soybean Disease Laboratory at the National Soybean Research Center, and then at the Plant Disease Clinic, University of Illinois. Tan, angular lesions that were 2 to 4 mm in diameter were observed on the lower leaf surfaces of two of the 20 leaflets. Within these lesions, there was one uredinum on one leaflet and four on the other leaflet exuding hyaline, echinulate urediniospores (20 × 25 µm). On 11 October 2006, these leaflets were sent by overnight courier to the USDA/APHIS/PPQ/NIS Laboratory, Beltsville, MD Plant Disease Clinic for identification by morphological examination and by PCR using primers specific to Phakopsora pachyrhizi (1). Both tests confirmed the presence of P. pachyrhizi. The 18 leaflets that did not have sporulating pustules on 11 October were incubated in the laboratory for 5 days at near 100% relative humidity. Following incubation, nine leaflets were observed to have uredinia exuding urediniospores with a range of 1 to 43 uredinia per leaflet. These results indicate that incubation may be necessary to maximize the potential to observe uredinia exuding urediniospores. To our knowledge, this is the first report of P. pachyrhizi infecting plants in Illinois. References: (1) R. D. Frederick et al. Phytopathology 92:217, 2002. (2) R. W. Schneider et al. Plant Dis. 89:774, 2005.

Magnetic domain-wall logic.

"Spintronics," in which both the spin and charge of electrons are used for logic and memory operations, promises an alternate route to traditional semiconductor electronics. A complete logic architecture can be constructed, which uses planar magnetic wires that are less than a micrometer in width. Logical NOT, logical AND, signal fan-out, and signal cross-over elements each have a simple geometric design, and they can be integrated together into one circuit. An additional element for data input allows information to be written to domain-wall logic circuits.

A questionnaire survey of attitudes to and usage of sunscreens in northwest England.

BACKGROUND/PURPOSE: Sunscreens are employed with the aim of reducing the deleterious effects of ultraviolet radiation (UVR), but little is known about their use in the UK. METHODS: This questionnaire survey assessed attitudes to and usage of sunscreens in northwest England in 2000. Subjects (186 females and 102 males) were recruited from the waiting rooms of four general practices, with a high response rate of 97%. RESULTS: Females were more frequent users of sunscreens than males, but only 35% females and 8% males reported their regular use. Twenty-two per cent of the study population did not use sunscreens at all, whereas 66% of subjects bought a sunscreen product once a year or less. Thirty-four per cent subjects reported experiencing sunburn in the last 2 years. Interestingly, more (60%) sunburns were found to occur at home in the UK than on holidays abroad, and these frequently occurred during outdoor activities other than deliberate sunbathing. CONCLUSION: There remains much scope for sunscreen education in the British public.

Nonsynchronized segmented heterochromia in black scalp hair.

Nonsynchronized segmented heterochromia in black scalp hair is a rarely reported entity, the only previous report being described in association with iron deficiency anaemia. A 14-year-old girl presented with a 2-year history of nonsynchronized segmented heterochromia. She was otherwise well and her serum iron, copper, zinc and protein levels were all within the normal range. She had no clinical evidence of vitiligo or alopecia areata. This patient is believed to represent the first reported case of nonsynchronized segmented heterochromia in black scalp hair as a presentation of premature greying of the hair.

Submicrometer ferromagnetic NOT gate and shift register.

An all-metallic submicrometer device is demonstrated experimentally at room temperature that performs logical NOT operations on magnetic logic signals. When this two-terminal ferromagnetic structure is incorporated into a magnetic feedback loop, the junction performs a frequency division operation on an applied oscillating magnetic field. Up to 11 of these junctions are then directly linked together to create a magnetic shift register.

Angiocaulus gubernaculatus in the island fox (Urocyon littoralis) from the California Channel Islands and comments on the diagnosis of angiostrongylidae nematodes in canid and mustelid hosts.

Adult nematode parasites were recovered from the heart blood of a deceased island fox (Urocyon littoralis) submitted for necropsy to determine the cause of death. Examination of the recovered nematodes supported the generic diagnosis of Angiocaulus, a parasite in Angiostrongylidae found in domestic and wild canids and mustelids. Specific diagnosis of the worms from the island fox as Angiocaulus gubernaculatus is based on the morphology of the dorsal ray in the copulatory bursa of the male worm and its comparison with published descriptions of Angiocaulus raillieti and A. gubernaculatus. Although A. gubernaculatus has been typically associated with mustelid hosts, its occurrence in the island fox indicates that the host distribution for the parasite may not be as restricted as previously believed.

Archeological evidence of parasitic infection from the 19th century company town of Fayette, Michigan.

Archeological deposits from the 19th century company town of Fayette, Michigan were analyzed for evidence of endoparasitic infection in the human population residing in the town between 1867 and 1891. Three privies were associated with upper-income and middle-income neighborhoods; 2 household refuse disposal areas were found in a predominately lower-income immigrant working class neighborhood. Sediment samples from 2 privies associated with dwellings in the middle-income neighborhood were positive for eggs of the human whipworm Trichuris trichiura. The parasite was probably also present among residents of the lower income neighborhood, but the shallow nature of the refuse deposits in that locality precluded preservation of the eggs. Contemporary epidemiologic studies of helminth infections support the belief that T. trichiura may have been a common parasite of 19th century school-age children given the natural inclination of young children to defecate indiscriminately, play freely in the dirt, and eat without washing their hands.

Analysis of Mycobacterium tuberculosis transmission patterns in a homeless shelter outbreak.

SETTING: From July 1997 through May 1998, ten tuberculosis (TB) cases were reported among men in a Syracuse New York homeless shelter for men. OBJECTIVE AND DESIGN: Investigation to determine extent of, and prevent further, transmission of Mycobacterium tuberculosis. RESULTS: Epidemiologic and laboratory evidence suggests that eight of the ten cases were related. Seven cases had isolates with matching six-band IS6110 DNA fingerprints; the isolate from another case had a closely related fingerprint pattern and this case was considered to be caused by a variant of the same strain. Isolates from eight cases had identical spoligotypes. The source case had extensive cavitary disease and stayed at the shelter nightly, while symptomatic, for almost 8 months before diagnosis. A contact investigation was conducted among 257 shelter users and staff, 70% of whom had a positive tuberculin skin test, including 21 with documented skin test conversions. CONCLUSIONS: An outbreak of related TB cases in a high-risk setting was confirmed through the use of IS6110 DNA fingerprinting in conjunction with spoligotyping and epidemiologic evidence. Because of the high rate of infection in the homeless population, routine screening for TB and preventive therapy for eligible persons should be considered in shelters.

A behavioral comparison of female adolescent inpatients with and without borderline personality disorder.

Patients with borderline personality disorder (BPD) are thought to have problematic hospitalizations. This study seeks to examine this phenomenon in adolescence by documenting the specific problem behaviors exhibited by patients, and the staff interventions in response to these behaviors in patients with and without BPD. Data were collected from the charts of 81 hospitalized adolescent girls regarding restraints, seclusions, incidents of self-abuse and aggression, incidents of signing the intent-to-leave form, nonroutine drug and/or alcohol screens, and discharges against medical advice. The two groups were compared using the analysis of variance (ANOVA) statistic for continuous variables and the chi-square statistic for the categorical variable. A follow-up multivariate ANOVA (MANOVA) was performed using the length of stay as a covariate. The BPD group displayed significantly higher rates of certain behaviors per day, but not of others. The length of stay was significantly higher in the BPD group. Further analysis indicated that some of the behavioral differences between the two groups may be due to the effect of the difference in length of stay. The data also suggest that while most BPD patients behave similarly to other patients, there may be a subset of BPD patients who behave in an extreme manner while hospitalized. BPD patients may display more of certain problematic behaviors than non-BPD patients in the hospital. However, it is hypothesized that these differences in hospital behavior may be largely due to the different lengths of stay between the two groups or to an acting-out subgroup of BPD patients.

Decreased seroprevalence for Toxoplasma gondii in Seventh Day Adventists in Maryland.

Despite its widespread prevalence, uncertainties remain about the relative contribution of various routes of transmission to the overall rate of infection with Toxoplasma gondii, particularly in developed countries. To explore the hypothesis that meat consumption is an important risk factor for infection, a cross-sectional seroprevalence study was performed on healthy adults in one region in the state of Maryland. The population included Seventh Day Adventists who as a group follow a diet containing no meat, and control community volunteers who were not Seventh Day Adventists. Thirty-one percent of the population had serologic evidence of T. gondii infection. People with T. gondii infection were older (49 versus 42 years old; P < 0.01, by t-test) and less likely to be Seventh Day Adventists (24% versus 50%; P < 0.01, by chi-square test) than people without T. gondii infection. When adjustments were made for age and gender through multiple logistic regression, Seventh Day Adventists had a significantly decreased risk of T. gondii infection (odds ratio = 0.21, 95% confidence interval = 0.09-0.46, P = 0.0001) compared with the controls. While the basis for this effect remains to be determined, one possible protective factor is the general adherence of Seventh Day Adventists to a diet that does not contain meat.

Knowledge, views, and experience of 25 women with myotonic dystrophy.

Twenty-five affected women of reproductive age known to the North West Regional Genetics Family Register (NWRGFR) were interviewed. A semistructured questionnaire, completed by the interviewer, was used to assess understanding and experience of the clinical and genetic aspects of myotonic dystrophy (MD) and attitudes to prenatal diagnosis (PND). Characteristic features of MD (muscle weakness and wasting and myotonia) were well known. Knowledge of other features and complications reflected experience. All subjects were aware that MD is inherited, but only 56% (14/25) knew the risk to their own children and subjects tended to overestimate this risk. Anticipation and maternal transmission of congenital myotonic dystrophy (CMD) were often misunderstood. Almost half of the subjects (12/25) perceived themselves to be moderately or severely affected and 40% (10/25) felt that their symptoms restricted daily life. Feelings of devastation, depression, worry about the future, and guilt at the risk of transmission to their children were described. Many subjects (10/25) said that the worst aspect of MD is the risk of transmission to their children. Over half (14/25) said that the risk of transmitting MD had influenced or would influence their own reproduction. Three-quarters of subjects who felt that MD had influenced their reproductive decisions (9/12) chose to limit their family or have no children; only 25% (3/12) requested PND. Subjects felt that the lack of information concerning clinical severity made PND for MD difficult to consider.

Patient, visitor, and nurse evaluations of visitation for adult postanesthesia care unit patients.

Although PACU visitation for children is sometimes encouraged, most families of adult postoperative patients continue to be excluded from PACUs in this country. At an academic medical center, an open visitation policy for adult postoperative patients was evaluated by eliciting patient, visitor, and nurse evaluations of visitation for adult patients from 181 families. Commonly cited reasons for restricting PACU visitation were not identified as problems by the vast majority of respondents. Even when some aspect of a PACU visit was disturbing, patients and families expressed a desire for visitation. The results of this evaluation of a change in practice led to permanent implementation of an open visitation policy in this PACU.

Gene expression and production of tumor necrosis factor alpha, interleukin 1, interleukin 6, and gamma interferon in C3H/HeN and C57BL/6N mice in acute Mycoplasma pulmonis disease.

Studies were conducted to determine whether the production of various cytokines is associated with Mycoplasma pulmonis disease expression. Susceptible C3H/HeN and resistant C57BL/6N mice were inoculated intranasally with 10(7) CFU of virulent M. pulmonis UAB CT or avirulent M. pulmonis UAB T. Expression of genes for tumor necrosis factor alpha (TNF-alpha), interleukin 1 alpha (IL-1 alpha), IL-1 beta, IL-6, and gamma interferon (IFN-gamma) in whole lung tissue and TNF-alpha gene expression in bronchoalveolar lavage (BAL) cells was determined by reverse transcription-PCR using specific cytokine primers at various times postinoculation. In addition, concentrations of TNF-alpha, IL-1, IL-6, and IFN-gamma were determined in BAL fluid and serum samples at various times postinoculation. Our results showed that there was a sequential appearance of cytokines in the lungs of infected mice: TNF-alpha, produced primarily by BAL cells, appeared first, followed by IL-1 and IL-6, which were followed by IFN-gamma. Susceptible C3H/HeN mice had higher and more persistent concentrations of TNF-alpha and IL-6 in BAL fluid than did resistant C57BL/6N mice, indicating that TNF-alpha and possibly IL-6 are important factors in pathogenesis of acute M. pulmonis disease in mice. Serum concentrations of IL-6 were elevated in C3H/HeN mice, but not C57BL/6N mice, following infection with M. pulmonis, suggesting that IL-6 has both local and systemic effects in M. pulmonis disease.