Polarization of both major body axes in Drosophila by gurken-torpedo signalling

Anterior-posterior polarity in Drosophila arises from the movement of the oocyte to the posterior of the egg chamber, and the subsequent acquisition of posterior fate by the adjacent somatic follicle cells. We demonstrate that gurken is necessary in the oocyte and torpedo/DER in the follicle cells for the induction of posterior fate. As the gurken-torpedo/DER pathway also establishes dorsoventral polarity later in oogenesis, Drosophila uses the same germline to soma signalling pathway to determine both embryonic axes.

Community nutrition education for people with coronary heart disease--who attends?

A qualitative food-frequency questionnaire was administered by mail to a representative sample of 137 people previously diagnosed with possible or definite myocardial infarct. Seventy-eight percent of subjects returned a completed questionnaire and were subsequently invited to attend local tastings of foods with the National Heart Foundation Tick of Approval. These tastings were organised and promoted with the active involvement of the local branch of the Australian Cardiac Association. The purpose of this study was to measure voluntary participation by people with coronary heart disease in community nutrition education and to identify any self-selection bias with respect to eating habits among the participants. A dietary risk score, which was the proportion of all food choices that were high in fat, was calculated from the data. Eighteen per cent of subjects who answered also participated in the food tastings; there was a statistically significant association between membership of the Australian Cardiac Association and being a participant. Participants had a significantly lower risk score (P < 0.01) after adjustment for age, sex and membership of the association. The results suggest that voluntary participation by people with heart disease in community nutrition education is low and that there is a self-selection bias, with those at highest dietary risk being least likely to attend. The use of existing community networks to recruit participants is also discussed.

Hard-of-hearing or deaf: issues of ears, language, culture, and identity

Most social work caseloads include some people who are deaf or hard-of-hearing, yet few social workers are attuned to the different and subtle ways in which hearing impairment can affect identity and relationships. People with hearing impairment make many self-defining choices--of communication method; language; and social, cultural, and political allegiance. Using information collected during a three-year research study of people with acquired hearing loss, this article defines and describes the complex and interrelated dimensions involved in assessing and serving people who are deaf or hearing impaired.

Cytological changes preceding cervical cancer

Cervical smears were reviewed from 62 women who developed squamous carcinoma of the cervix up to 18 years later. The findings indicate that the prevention of cervical cancer by screening depends very largely on the detection of severe dyskaryosis. In this series there was no evidence that mild dyskaryosis was a forerunner of invasive disease. Cytology during the evolution of squamous carcinoma is not characterised by a dyskaryosis which progressively increases in severity. Instead the findings support new concepts that cervical cancer generally arises from an aggressive CIN 3 lesion widely present in the cervix, and in our series, established years before invasion occurs. It would be more useful to report cytology as showing either a low or high grade abnormality rather than distinguishing between different degrees of dyskaryosis.

Reducing blood cholesterol levels in patients with peripheral vascular disease: dietitian or diet fact sheet?

A randomized trial was performed to test the hypothesis that, among patients with peripheral vascular disease, no difference is achieved in the magnitude of the reduction in blood cholesterol levels as a result of advice which is provided by a dietitian and that which is provided by a diet fact sheet. Fifty-nine patients were allocated at random either to a "dietitian" group (n = 31) or to a "diet fact sheet" group (n = 28). Dietary advice which was provided by a dietitian involved two personal interviews; the diet fact sheet was prepared by the NSW Department of Health. Twenty-two and 23 members of each group, respectively, returned for follow-up at three months. The mean cholesterol level fell by 8.5% among the "dietitian" group but only by 1.9% among the "diet fact sheet" group. The difference of 0.47 mmol/L in the total cholesterol level reduction between the two groups was statistically significant (P = 0.02; 95% confidence interval, -0.88 to -0.07 mmol/L). It appears that individual advice which is provided by a dietitian is more successful in leading to a reduction in blood cholesterol levels than is the administration of a diet fact sheet, even though this particular diet fact sheet appears to be excellent and is used widely. In view of the large numbers of patients and of persons in the population as a whole who would benefit from a reduction in blood cholesterol levels, and the expense of individual advice to be provided by a dietitian, explorations of cost-effective methods of providing dietary advice are needed.

Assessment of oesophagitis by histology and morphometry

Morphometric measurements of nuclear area, nuclear concentration and nucleolar dimensions in defined tissue zones of orientated oesophageal biopsy sections were compared between three patient groups--asymptomatic/normal endoscopy (n = 8); symptomatic reflux/normal endoscopy (n = 17); and symptomatic/endoscopic oesophagitis (n = 15). No significant differences could be shown for any mean parameter between clinical groups. In a further group of 16 patients, identical morphometric measurements were made in non-orientated grasp biopsies and correlated with prolonged ambulatory pH data. No significant correlations could be shown between nuclear parameters and acid reflux measurements. These results suggest that morphometric measurement cannot be recommended as a diagnostic tool in the diagnosis of oesophagitis, although it may be useful in the assessment of individual therapeutic response in clinical trials.

Modeling and segmentation of noisy and textured images using gibbs random fields

This paper presents a new approach to the use of Gibbs distributions (GD) for modeling and segmentation of noisy and textured images. Specifically, the paper presents random field models for noisy and textured image data based upon a hierarchy of GD. It then presents dynamic programming based segmentation algorithms for noisy and textured images, considering a statistical maximum a posteriori (MAP) criterion. Due to computational concerns, however, sub-optimal versions of the algorithms are devised through simplifying approximations in the model. Since model parameters are needed for the segmentation algorithms, a new parameter estimation technique is developed for estimating the parameters in a GD. Finally, a number of examples are presented which show the usefulness of the Gibbsian model and the effectiveness of the segmentation algorithms and the parameter estimation procedures.

Diagnosis of Maroteaux-Lamy syndrome by the use of radiolabelled oligosaccharides as substrates for the determination of arylsulphatase B activity

The kinetic parameters (Km and V) of human arylsulphatase B (4-sulpho-N-acetylgalactosamine sulphatase) activity in cultured skin fibroblasts were determined with a variety of substrates matching structural aspects of the physiological substrates in vivo chondroitin 4-sulphate and dermatan sulphate. More structurally complex substrates, in which several aspects of the aglycone structure of the natural substrate were maintained, were desulphated up to 4400 times faster than the minimum arylsulphatase-B-specific substrate, namely the monosaccharide N-acetylgalactosamine 4-sulphate. Aglycone structures that influence substrate binding and/or enzyme activity were an adjacent-residue C-6 carboxy group and a second but internal N-acetylgalactosamine 4-sulphate residue. Arylsulphatase B activity in fibroblast homogenates assayed with O-(beta-N-acetylgalactosamine 4-sulphate)-(1----4)-O-D-(beta-glucuronic acid)-(1----3)-O-D-N-acetyl[1-3H] galactosaminitol 4-sulphate derived from chondroitin 4-sulphate as substrate clearly distinguished Maroteaux-Lamy-syndrome patients from normal controls and other mucopolysaccharidosis patients. We recommend the use of the above trisaccharide substrate for both postnatal and prenatal diagnosis of Maroteaux-Lamy syndrome.

Oesophageal histology in reflux oesophagitis

Multiple specimens taken at oesophageal suction biopsy were obtained from 56 patients, of whom 44 had symptoms of gastro-oesophageal reflux and 24 had endoscopic evidence of erosive oesophagitis. Biopsies were examined independently by two histopathologists for the following criteria for reflux: epithelial hyperplasia, vascular dilatation and congestion, neutrophil infiltration, and eosinophil infiltration. The incidence of these criteria in patients with and without endoscopic evidence of oesophagitis or symptoms of reflux was investigated. It was concluded that vascular dilatation and epithelial hyperplasia, defined as basal zone thickness greater than or equal to 15% and papillary elongation greater than or equal to 66%, can be detected most reliably, but their diagnostic accuracy is limited unless multiple biopsies are examined.

Urinary excretion of sulphated N-acetylhexosamines in patients with various mucopolysaccharidoses

Sulphated N-acetylhexosamines have been isolated from human urine and tentatively identified as N-acetylglucosamine 6-sulphate (GlcNAc6S), N-acetylgalactosamine 6-sulphate (GalNAc6S), N-acetylgalactosamine 4-sulphate (GalNAc4S) and N-acetylgalactosamine 4,6-disulphate (GalNAc4,6diS). Urine from mucopolysaccharidosis-Type-IIID, -IVA and -VI patients compared with that from normal individuals contains elevated levels of GlcNAc6S (380-fold), GalNAc6S (180-fold) and GalNAc4S (420-fold) respectively. Urine from mucopolysaccharidosis-Type-VI patients also contain more than 600 times the normal level of GalNAc4,6diS. Urine from a mucolipidosis-Type-II and a multiple-sulphatase-deficient patient, and, in general, all mucopolysaccharidosis patients studied, contain at least 5-10-fold elevations of sulphated N-acetylhexosamines over the levels detected in urine from normal controls and a alpha-mannosidosis patient. Urine from patients with clinically mild phenotypes contains less sulphated N-acetylhexosamines than isolated from urine of clinically severe mucopolysaccharidosis patients. The source of the four sulphated N-acetylhexosamines is not known. However, incubation of a series of oligosaccharide substrates, derived from keratan sulphate and chondroitin 6-sulphate and containing non-reducing-end beta-linked 6-sulphated N-acetylhexosamine residues, with homogenates of cultured human skin fibroblasts has indirectly been shown to release GlcNA6S and GalNAc6S respectively. Release of GalNAc4S could not be demonstrated in similar incubations of oligosaccharide substrates derived from chondroitin 4-sulphate and containing non-reducing-end beta-linked GalNAc4S residues. We propose that some, if not all, of the sulphated N-acetylhexosamine present in human urine is derived from the action of beta-N-acetylhexosaminidase on sulphated GlcNAc or GalNAc residues at the non-reducing end of keratan sulphate, dermatan sulphate or chondroitin sulphate.

Bayes smoothing algorithms for segmentation of binary images modeled by markov random fields

A new image segmentation algorithm is presented, based on recursive Bayes smoothing of images modeled by Markov random fields and corrupted by independent additive noise. The Bayes smoothing algorithm yields the a posteriori distribution of the scene value at each pixel, given the total noisy image, in a recursive way. The a posteriori distribution together with a criterion of optimality then determine a Bayes estimate of the scene. The algorithm presented is an extension of a 1-D Bayes smoothing algorithm to 2-D and it gives the optimum Bayes estimate for the scene value at each pixel. Computational concerns in 2-D, however, necessitate certain simplifying assumptions on the model and approximations on the implementation of the algorithm. In particular, the scene (noiseless image) is modeled as a Markov mesh random field, a special class of Markov random fields, and the Bayes smoothing algorithm is applied on overlapping strips (horizontal/vertical) of the image consisting of several rows (columns). It is assumed that the signal (scene values) vector sequence along the strip is a vector Markov chain. Since signal correlation in one of the dimensions is not fully used along the edges of the strip, estimates are generated only along the middle sections of the strips. The overlapping strips are chosen such that the union of the middle sections of the strips gives the whole image. The Bayes smoothing algorithm presented here is valid for scene random fields consisting of multilevel (discrete) or continuous random variables.

Detection of the Sanfilippo D syndrome by the use of a radiolabeled monosaccharide sulfate as the substrate for the estimation of N-acetylglucosamine-6-sulfate sulfatase

N-Acetylglucosamine-6-sulfate sulfatase activity was assayed by incubation of the radiolabeled monosaccharide N-acetylglucosamine [1-14C]6-sulfate (GlcNAc6S) with homogenates of leukocytes and cultured skin fibroblasts and concentrates of urine derived from normal individuals, patients affected with N-acetylglucosamine-6-sulfate sulfatase deficiency (Sanfilippo D syndrome, mucopolysaccharidosis type IIID), and patients affected with other mucopolysaccharidoses. The assay clearly distinguished affected homozygotes from normal controls and other mucopolysaccharidosis types. The level of enzymatic activity toward GlcNAc6S was compared with that toward a sulfated disaccharide and a sulfated trisaccharide prepared from heparin. The disaccharide was desulfated at the same rate as the monosaccharide and the trisaccharide at 30 times that of the monosaccharide. Sulfatase activity toward glucose 6-sulfate and N-acetylmannosamine 6-sulfate was not detected. Sulfatase activity in fibroblast homogenates with GlcNAc6S exhibited a pH optimum at pH 6.5, an apparent Km of 330 mumol/liter, and inhibition by both sulfate and phosphate ions. The use of radiolabeled GlcNAc6S substrate for the assay of N-acetylglucosamine-6-sulfate sulfatase in leukocytes and skin fibroblasts for the routine enzymatic detection of the Sanfilippo D syndrome is recommended.

Detection of Morquio A syndrome using radiolabelled substrates derived from keratan sulphate for the estimation of galactose 6-sulphate sulphatase

1. The following radiolabelled disaccharide and tetrasaccharide were prepared from keratan sulphate and evaluated as substrates for galactose 6-sulphate sulphatase present in cultured human skin fibroblasts: O-(β-d-6-sulphogalactosyl)−(1 → 4)−2,5-anhydro-d-[1-3H] mannitol 6-sulphate (Gal6S-anM6S) and the tetrasaccharide equivalent Gal6S-GlcNAc6S-Gal6S-anM6S. Radiolabelled trisaccharide substrates, N-acetylgalactosamine 6-sulphate (β, 1 → 4)-glucuronic acid-(β 1→3)-N-acetyl[l-3H]galactosaminitol 6-sulphate (GalNAc6S-GlcA-GalitolNAc6S), and N-acetylgalactosamine 6-sulphate (β, 1 → 4)-glucose-(β, 1 → 3)-N-acetyl-[1-3H]galactosaminitol 6-sulphate (GalNAc6S-GlcGalitol-NAc6S), were prepared from chondroitin 6-sulphate and used to assay N-acetylgalactosamine 6-sulphate sulphatase.

2. Sulphatase activity obtained with Gal6S-anM6S was approximately the same, 100 and 30–50 times less than values obtained with Gal6S-GlcNAc6S-Gal6S-anM6S, GalNAc6S-GlcA-Galitol-NAc6S and GalNAc6S-Glc-GalitolNAc respectively. Less than 5% of normal activity resulted when these substrates were incubated with fibroblasts from Morquio A patients. These results demonstrate that the trisaccharide substrates derived from chondroitin 6-sulphate although de-O-sulphated at a considerably higher rate than was observed for the de-O-sulphation of the disaccharide and tetrasaccharide derived from keratan sulphate, are acted upon by the same sulphatase.

3. Galactose 6-sulphate sulphatase activity in fibroblast homogenates assayed with Gal6S-anM6S as substrate clearly distinguished Morquio A patients from normal controls, and Morquio B and Sanfilippo D patients.

4. We recommend the use of both the radiolabelled disaccharide derived from keratan sulphate and the trisaccharide derived from chondroitin 6-sulphate to assess sulphatase activity in fibroblasts of atypical Morquio patients.

Selective depolymerisation of keratan sulfate: production of radiolabelled substrates for 6-O-sulfogalactose sulfatase and beta-D-galactosidase

Keratan sulfate (KS) was N-deacetylated with anhydrous hydrazine and then degraded with nitrous acid, and the products were reduced with NaBT4. Radiolabelled disaccharides constituted at least 76% of the total oligosaccharide fraction. Three major disaccharides were isolated and identified. Of the total disaccharide isolated from bovine intervertebral-disc and human costal-cartilage, 91 and 79%, respectively, was identified as a disulfated disaccharide, O-(beta-D-galactopyranosyl 6-sulfate)-(1 leads to 4)-2,5-anhydro-D-[1-3H]mannitol 6-sulfate (Gal6S-anM6S). The disaccharide fraction isolated from bovine-cornea KS contained only 14% of Gal6S-anM6S. The yield of monosulfated disaccharide, identified as O-beta-D-galactopyranosyl-(1 leads to 4)-2,5-anhydro-D-[1-3H]mannitol 6-sulfate, was 9, 17, and 84% of the total KS-disaccharide fraction isolated from intervertebral disc, costal cartilage, and cornea, respectively. For each of the KS type studied, the yield of unsulfated disaccharide was less than 4% of the total disaccharide-fraction. The tetrasaccharides were fractionated, on the basis of their sulfate content, into at least four species by paper electrophoresis, and some tentative structures are proposed. Disaccharide and tetrasaccharide species were evaluated as substrates for beta-D-galactosidase and 6-O-sulfogalactose sulfatase.

Isolation and characterization of N-acetylglucosamine 6-sulfate from the urine of a patient with Sanfilippo type D syndrome and its occurrence in normal urine

N-Acetylglucosamine 6-sulfate (GlcNAc6S) has been isolated from human urine and shown to be present at levels of approximately 0.02 and 14 mg/mmole creatinine in urine from normal individuals and a mucopolysaccharidosis type IIID (MPS IIID) patient respectively. We propose that the greater than 500-fold elevation of GlcNAc6S in urine from the MPS IIID patient indicates that this sulfated monosaccharide is also a substrate for the sulfatase deficient in MPS IIID patients. We further propose that part, if not all, of the GlcNAc6S found in urine may be produced from the cleavage by beta-N-acetylhexosaminidase A of non-reducing end beta-linked GlcNAc6S residues of keratan sulfate and/or sulfated glycoproteins.