Antenatal sonographic diagnosis of thanatophoric dysplasia: a report of three cases and a review of the literature with special emphasis on the differential diagnosis.

A series of three cases is reported in which the diagnosis of thanatophoric dysplasia was reached at routine mid-trimester scanning in a District General Hospital. All three patients underwent termination of pregnancy with the diagnosis of thanatophoric dysplasia confirmed by postmortem radiographic and histological examinations. A review of the current literature on thanatophoric dysplasia is given, with special emphasis on the differentiation of the main types of thanatophoric dysplasia from other skeletal abnormalities.

Effectiveness of routine ultrasonography in detecting fetal structural abnormalities in a low risk population.

OBJECTIVE: To review the efficacy of routine prenatal ultrasonography for detecting fetal structural abnormalities. DESIGN: Retrospective study of the ultrasonographic findings and outcome of all pregnancies in women scanned in 1988-9. SETTING: Maternity ultrasonography department of a district general hospital. SUBJECTS: 8785 fetuses. MAIN OUTCOME MEASURES: Correlation of prenatal ultrasonographic findings with outcome in the neonate. RESULTS: 8733 babies were born during 1988-9, and 52 pregnancies were terminated after a fetal malformation was identified. 8432 (95%) of the fetuses were examined by ultrasonography in the second trimester. 130 fetuses (1.5%) were found to have an abnormality at birth or after termination of pregnancy, 125 of which had been examined in the second trimester. In 93 cases the abnormality was detected before 24 weeks (sensitivity 74.4%, 95% confidence interval to 66.7% to 82.1%. Two false positive diagnoses occurred, in both cases the pregnancies were not terminated and apparently normal infants were born. This gives a specificity of 99.98% (99.9% to 99.99%). The positive predictive value of ultrasonography in the second trimester was 97.9% (92.6% to 99.7%). Of the 125 abnormalities, 87 were lethal or severely disabling; 72 of the 87 were detected by the routine screening programme (sensitivity 82.8%, 73.2% to 90.0%). CONCLUSION: Routine fetal examination by ultrasonography in a low risk population detects many fetal structural abnormalities but can present several dilemmas in counselling.

In-vitro antibiotic inactivation by mammalian cell and killed bacterial preparations.

Inactivation of a range of antibiotics acting at different points in the metabolism of the bacterial cell was detected by estimating the MIC and MBC in the presence of liver and other tissue preparations. High temperature treatment and sonication of liver cells increased their ability to inactivate antibiotic action. This treatment would have almost completely destroyed enzyme activity, which was, therefore, not thought likely to be the cause of the phenomenon. The loss of antibiotic activity may be related to "protein binding" and a dialysis experiment showed that penicillin binding with liver homogenate was very much greater than with human albumin. It may be that increased disruption of tissue cells by physical methods exposes more active binding sites which reduces the bioavailability of antibiotics. Some degree of binding specificity was indicated in experiments in which DNA was shown to block antibiotics acting primarily on DNA--related synthesis and RNA blocked antibiotics acting on RNA--related metabolism. Suggestions are made for the cause of failure of antibiotic treatment in certain clinical situations.

Clinical associations of Aeromonas spp. in fecal specimens from children.

Human infections caused by Aeromonas spp. are being reported with increased frequency. We examined 1012 unselected stool specimens from 799 children for various pathogens, including Aeromonas spp., to evaluate the clinical associations of Aeromonas spp. in the stools of children in the East End of London. A total of 33 children had positive cultures for Aeromonas spp. These were identified as: Aeromonas hydrophila (16), A. sobria (9), A. caviae (8). Aeromonas spp. were identified by being oxidase positive in character, a property that distinguishes Aeromonas spp. from Enterobacteriaceae. Associated pathogens included Salmonella typhimurium (1), Campylobacter spp. (3), Enteropathogenic Escherichia coli (2), and Giardia lamblia (1). Electron microscopic examination of the stool of 13 children revealed viral particles in two, rotavirus (1), and coronavirus-like particles (1). The associated clinical features in the 25 children with only Aeromonas excretion were diarrhea (21), vomiting (10), abdominal pain (9), fever (4), and mild dehydration (2). Five patients had macroscopic blood loss in the stools. The illness was generally mild and lasted only a short time.

Cryptosporidiosis in immunocompetent children.

Cryptosporidial oocysts were identified by modified Ziehl-Neelsen stain in the stools of seven (3.2%) of 213 children with acute or chronic diarrhoea and one (0.9%) of 112 controls. All children with cryptosporidia were immunocompetent. Four of the index cases had a short illness (3-14 days) with watery diarrhoea, vomiting (2), and abdominal pain (2). Two index cases had chronic diarrhoea for over four months and failure to thrive. Both had a small intestinal enteropathy; one had cryptosporidial oocysts in stool specimens two months apart and the other had cryptosporidial schizonts attached to the jejunal mucosa. One index case had a colitis of indeterminate cause. Four of the index cases had recently travelled abroad. There had been an outbreak of gastroenteritis in the family of one of the index cases, and three affected sisters and an asymptomatic brother had oocysts in their stools. Cryptosporidial infestation seems to be associated with acute gastroenteritis and sometimes with chronic diarrhoea and small bowel damage in immunocompetent children.

Comparison of a homemade blood culture broth containing a papain digest of liver, with four commercially available media for the isolation of anaerobes from simulated paediatric blood cultures.

The recovery of small inocula of fastidious organisms, mainly non-sporing anaerobes, was studied in simulated paediatric blood culture experiments where only 1.5 ml of blood was added to each broth. A 25 ml homemade Queen Elizabeth Hospital medium (QEH medium) containing a papain digest of liver showed the best overall performance during the first four days of incubation; this medium was also satisfactory for maintenance of the majority of the organisms tested for longer than one week. LAB M Fastidious Anaerobe Broth (75 ml) with thymidine, also showed early isolation and satisfactory survival of most organisms. Difco Thiol broth, 50 ml with Liquoid, yielded early growth of the three strains of Bacteroides fragilis tested and maintained these organisms well; however, variable results were obtained with some other organisms in Difco Thiol media. Southern Group Brewer's thioglycollate broth (80 ml) gave the least satisfactory performance.

Images of truncated one-dimensional periodic bar targets in aberration-limited optical systems.

This paper deals with the properties of the images of truncated one-dimensional periodic bar targets formed by aberration-limited optical systems. Attention is directed to the problem of determining how many bars are required at a given spatial frequency in order to obtain an image which closely approximates that for an infinite-chain periodic bar target. Numerical calculations are carried out for the case of an aberration-limited, glancing-incidence x-ray telescope.