Rapid Flagella Stain

Leifson stain was modified to produce rapid staining of bacterial flagella on untreated microscope slides. The procedure was reliable when tested against a variety of motile and nonmotile bacteria.     

Association of DLG5 R30Q variant with inflammatory bowel disease

Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory diseases of the gastrointestinal system known as the inflammatory bowel diseases (IBD). Recently, Stoll and colleagues reported a novel finding of genetic variation in the DLG5 gene that is associated with IBD (CD and UC combined). We present here a study of the genetic variation described in that report in two well-powered, independent case-control cohorts and one family-based collection, and confirm the proposed association between IBD and the R30Q variant of DLG5 in two of the three studies. We are, however, unable to replicate the other proposed association to the common haplotype described in Stoll et al and suggest that this other finding could conceivably have been partially a statistical fluctuation and partially a result of LD with the replicated R30Q association. This study provides support for the hypothesis that DLG5 constitutes a true IBD risk factor of modest effect.     

The efficacy of the heat killing of Mycobacterium tuberculosis

There is concern that current procedures for the heat inactivation of Mycobacterium tuberculosis may not be adequate. This raises serious safety issues for laboratory staff performing molecular investigations such as IS6110 restriction fragment length polymorphism typing. This paper confirms that the protocol of van Embden et al, as performed routinely in this laboratory, is safe and effective for the heat inactivation of M tuberculosis. This procedure involves complete immersion of a tube containing a suspension of one loopfull of growth in a water bath at 80 degrees C for 20 minutes. Seventy four isolates were included in this investigation. Despite prolonged incubation for 20 weeks, none of the heat killed M tuberculosis suspensions produced visible colonies or gave a positive growth signal from liquid culture. This method did not affect the integrity of the DNA for subsequent molecular investigations.     

Life expectancy in British Marfan syndrome populations

A total of 206 patients with Marfan syndrome were ascertained throughout genetic clinics in Wales and Scotland during the period 1970–1990. There were 45 deaths representing 22% of the cohort. Mean age at death was 45.3 ± 16.5 years. 50% median cumulative survival in the total cohort (n = 206) was 53 years for males and 72 years for females. Multivariate analysis confirmed severity as the best independent indicator of survival. These findings and survival curves will assist in the counselling of British families and individuals with Marfan syndrome.     

An introduction to stem cells

1998 saw the publication of two papers describing the growth in vitro of human embryonic stem (ES) cells derived either from the inner cell mass (ICM) of the early blastocyst or the primitive gonadal regions of early aborted fetuses. Work on murine ES cells over many years had already established the amazing flexibility of ES cells, essentially able to differentiate into almost all cells that arise from the three germ layers. The realization of such pluripotentiality (see below) has, of course, resulted in the field of stem cell research going into overdrive, the establishment of many new biotechnology companies (http://www.stemcellresearchnew.com/catalog1677.html), and a genuine belief that stem cell research will deliver a revolution in terms of how we treat cardiovascular disease, neurodegenerative disease, cancer, diabetes, and the like. However, many people believe that early human embryos should be accorded the same status as any sentient being and thus their 'harvesting' for stem cells is morally unjustifiable. With this in mind, other sources of malleable stem cells have been sought. In the adult, organ formation and regeneration was thought to occur through the action of organ- or tissue-restricted stem cells (i.e. haematopoietic stem cells giving rise to all the cells of the blood, neural stem cells making neurons, astrocytes, and oligodendrocytes). However, it is now believed that stem cells from one organ system, for example the haematopoietic compartment can develop into the differentiated cells within another organ system, such as the liver, brain or kidney. Thus, certain adult stem cells may turn out be as malleable as ES cells and so also be useful in regenerative medicine. This brief overview summarizes the important attributes of tissue-based stem cells and clarifies the terms used.     

Anxiety Treatment and Targeted Sleep Enhancement to Address Sleep Disturbance in Pre/Early Adolescents with Anxiety

Sleep disturbance is prevalent in anxious youth and prospectively predicts poor emotional adjustment in adolescence. Study 1 examined whether anxiety treatment improves subjective and objective sleep disturbance in anxious youth. Study 2 examined whether a sleep intervention called Sleeping TIGERS can further improve sleep following anxiety treatment. Study 1 examined 133 youth (ages 9–14; 56% female; 11% ethnic/racial minority) with generalized, social, or separation anxiety over the course of anxiety treatment (cognitive behavioral treatment or client-centered treatment). Sleep-related problems (parent-, child-report) and subjective (diary) and objective (actigraphy) sleep patterns were assessed across treatment in an open trial design. Study 2 included 50 youth (ages 9–14; 68% female; 10% ethnic/racial minority) who continued to report sleep-related problems after anxiety treatment and enrolled in an open trial of Sleeping TIGERS. Pre- and postassessments duplicated Study 1 and included the Focal Interview of Sleep to assess sleep disturbance. Study 1 demonstrated small reductions in sleep problems and improvements in subjective sleep patterns (diary) across anxiety treatment, but outcomes were not deemed clinically significant, and 75% of youth stayed above clinical cutoff. Study 2 showed clinically significant, large reductions in sleep problems and small changes in some subjective sleep patterns (diary). Anxiety treatment improves, but does not resolve, sleep disturbance in peri-pubertal youth, which may portend risk for poor emotional adjustment and mental health. The open trial provides preliminary support that Sleeping TIGERS can improve sleep in anxious youth to a clinically significant degree.     

Homozygosity mapping of achromatopsia to chromosome 2 using DNA pooling

Achromatopsia is an autosomal recessive disease of the retina, characterized clinically by an inability to distinguish colors, impaired visual acuity, nystagmus and photophobia. A genome-wide search for linkage was performed using an inbred Jewish kindred from Iran. To facilitate the genome-wide search, we utilized a DNA pooling strategy which takes advantage of the likelihood that the disease in this inbred kindred is inherited by all affected individuals from a common founder. Equal molar amounts of DNA from all affected individuals were pooled and used as the PCR template for short tandem repeat polymorphic markers (STRPs). Pooled DNA from unaffected members of the kindred was used as a control. A reduction in the number of alleles in the affected versus control pool was observed at several loci. Upon genotyping of individual family members, significant linkage was established between the disease phenotype and markers localized on chromosome 2. The highest LOD score observed was 5.4 (theta = 0). When four additional small unrelated families were genotyped, the combined peak LOD score was 8.2. Analysis of recombinant chromosomes revealed that the disease gene lies within a 30 cM interval which spans the centromere. Additional fine-mapping studies identified a region of homozygosity in all affected individuals, narrowing the region to 14 cM. A candidate gene for achromatopsia was excluded from this disease interval by radiation hybrid mapping. Linkage of achromatopsia to chromosome 2 is an essential first step in the identification of the disease-causing gene.      

Recombination aneusomy of chromosome 5 associated with multiple severe congenital malformations

A male infant is described in whom congenital anomalies were recognized prenatally by ultrasound examination. The infant was delivered following spontaneous labor and died approximately 15 min after birth. An autopsy revealed major anomalies in the central nervous system (holoprosencephaly with premaxillary agenesis), the gastrointestinal system (esophageal atresia) and the heart (tetralogy of Fallot). Chromosomal studies revealed recombinant chromosome 5 [46,XY, rec(5), dup q, inv(5)(p15q32)], resulting in partial trisomy 5q and partial monosomy 5p. Cytogenetic investigation of the family revealed a pericentric inversion of chromosome 5 in the father and paternal grandmother, 46,XY (and XX, respectively,) inv(5)(p15q32). The congenital anomalies in this infant are more extensive and severe than previously reported in cases of recombination aneusomy involving chromosome 5.     

Elevation of serum sex hormone-binding globulin in females with fulminant hepatitis B virus infection

Amongst adults exposed to the hepatitis B virus (HBV), the infection pursues a fulminant course more frequently in females, while conversely a chronic carrier state is more frequent in males. Because of these differences in sex ratio, we investigated the relationship between the outcome of HBV infection and serum concentrations of sex hormone-binding globulin (SHBG), a circulating glycoprotein that exerts an important influence on the balance of free sex hormones. SHBG levels were significantly elevated in females with fulminant HBV infection compared to females with either uncomplicated acute or chronic HBV infection (P less than .05 and P less than .001, respectively). That this was not a nonspecific effect of fulminant hepatitis was confirmed by the significantly higher levels in this group than in age-matched females with fulminant hepatitis unrelated to HBV (P less than .05). In contrast, four of 15 female HBsAg carriers had SHBG values in the male range, and these included three of four patients who had acquired HBV as adults. SHBG levels were normal in all male groups. These results suggested that for adults the hormonal environment may be important in determining the course of HBV infection.