Slug, a zinc finger gene previously implicated in the early patterning of the mesoderm and the neural crest, is also involved in chick limb development

The great advances made over the last few years in the identification of signalling molecules that pattern the limb bud along the three axes make the limb an excellent model system with which to study developmental mechanisms in vertebrates. The understanding of the signalling networks and their mutual interactions during limb development requires the characterisation of the corresponding downstream genes. In this study we report the expression pattern of Slug, a zinc-finger-containing gene of the snail family, during the development of the limb, and its regulation by distinct axial signalling systems. Slug expression is highly dynamic, and at different stages of limb development can be correlated with the zone of polarizing activity, the progress zone and the interdigital areas. We show that the maintenance of its expression is dependent on signals from the apical ectodermal ridge and independent of Sonic Hedgehog. We also report that, in the interdigit, apoptotic cells lie outside of the domains of Slug expression. The correlation of Slug expression with areas of undifferentiated mesenchyme at stages of tissue differentiation is consistent with its role in early development, in maintaining the mesenchymal phenotype and repressing differentiation processes. We suggest that Slug is involved in the epithelial-mesenchymal interactions that lead to the maintenance of the progress zone.     

Hospitalization for acute pyelonephritis in Manitoba, Canada, during the period from 1989 to 1992; impact of diabetes, pregnancy, and aboriginal origin

Population-based rates of hospitalization for acute pyelonephritis were estimated over 3 years with use of provincial administrative data on health care. Retrospective review of records of ICD9-CM discharge codes of pyelonephritis and urinary infection was performed in two acute care institutions to validate the discharge diagnosis; 80% of patients with a discharge diagnosis of pyelonephritis and 7% to 20% of patients with a discharge diagnosis of urinary infection met clinical criteria for admission for acute pyelonephritis. Mean rates of hospitalization +/- SD for acute pyelonephritis were 10.86 +/- 0.51 per 10,000 population among women and 3.32 +/- 0.27 per 10,000 population among men. From 18% to 31% of hospitalized women aged 20-39 years pregnant; 36% of 797 hospitalized women and 21% of 402 hospitalized men 40 years of age or older were diabetic. The hospitalization rates among Native American women with treaty status were five to 20 times greater than those among other women, which was partially attributable to a significantly greater frequency of pregnancy and diabetes in the former women. Hospitalization for acute pyelonephritis is common, and pregnancy and diabetes contribute substantially to hospitalization rates. The increased hospitalization rate among Native American women with treaty status is not fully explained by pregnancy or diabetes.     

Clinical picture of peptic ulceration diagnosed endoscopically

Clinical features and laboratory data are presented for 100 patients with benign gastric ulceration and 150 patients with duodenal ulceration confirmed endoscopically in a district general hospital unit. Abdominal pain was the commonest indication for endoscopy, but one third of examinations were performed for acute gastrointestinal haemorrhage. Although the patients were selected by referral for endoscopy their clinical presentation, age, and sex distribution were similar to those reported in previous general surveys. There were no clinical features which clearly distinguished gastric from duodenal ulceration. However, of those with gastric ulceration younger patients more often had distal ulcers and presented with pain, while elderly subjects tended to have high lesser curve involvement and presented with haemorrhage. Moreover, all females presenting with haemorrhage were aged over 50 years, while 6% of males bleeding from gastric ulceration and 40% of males bleeding from duodenal ulceration were under this age. Anaemia when present, except in two premenopausal females, indicated either a recent acute gastrointestinal haemorrhage or a coexistent second diagnosis.     

Infective endocarditis as a complication of heroin use

Infective endocarditis in heroin addicts has been reported to have a mortality as high as 85% and reports have varied widely regarding predominant valvular involvement and infecting microorganisms. A retrspective study was done and 61 cases of heroin-associated infective endocarditis were identified at Freedmen's Hospital and the District of Columbia General Hospital, Washington, DC between January 1969 and January 1973. Our results indicate that staphylococcal infection of the tricuspid valve has a much higher incidence in this population than has generally been believed and that it is the predominant presentation of infective endocarditis in these patients. The outcome of patients in our series compares favorably with previous reports and suggests that early diagnosis and prompt institution of appropriate antimicrobial therapy are important and may lead to improved survival in addicts with tricuspid endocarditis.     

Abnormal gastro-oesophageal reflux in Chinese with atypical chest pain

Although atypical chest pain has been well described in the Western population, its frequency in Chinese is unknown. Over a period of 42 months, we studied 521 Chinese patients with chest pain and identified 108 patients (20.7%) whose pain was not related to cardiac causes, as determined by exercise ECG or cardiac catheterization. Using 24 h ambulatory pH monitoring and baseline oesophageal manometry, 28.7, 19.4 and 5.6% of these patients were found to have abnormal reflux parameters, abnormal manometric findings or both, respectively. There were significantly more patients complaining of chest pain during the study in the gastro-oesophageal reflux disease (GERD) group than in the non-GERD group (16/31 vs 20/77; P < 0.001). The lower oesophageal sphincter pressure was lower in those with abnormal reflex parameters than in those with normal reflux parameters (12.7 +/- 5.4 vs 17.8 +/- 5.8 mmHg; P < 0.05). There was no significant difference in symptoms, such as heartburn (54.8 vs 42.9%), regurgitation (38.7 vs 35.1%) and dysphagia (19.4 vs 24.7%), among the two groups. Non-specific changes were the most frequent baseline motility pattern. In conclusion, atypical chest pain and gastro-oesophageal reflux disease are not uncommon in Chinese and this deserves special emphasis as the continuation of anti-anginal drugs may aggravate their condition.     

Visual accommodation and virtual images: do attentional factors mediate the interacting effects of perceived distance, mental workload, and stimulus presentation modality?

A study was conducted to examine the effect on the visual accommodation response of processing information presented either visually or aurally while viewing a real-world scene. A number of different conditions were tested in which a mental processing task, a virtual image overlaying the real world (as is the case with head-up displays), or both were present. These manipulations provided two factors that have previously been demonstrated to have some influence on the accommodation response: mental effort and perceived distance. They also allowed the investigation of the influence of the source modality of the information to be processed. The results suggested that these influences may have a cumulative effect on the visual accommodation response, possibly mediated by attentional factors.