Ring 21 chromosome: the mild end of the phenotypic spectrum

The case is reported of a child with the karyotype 46,XY,r(21), who presented with linear growth retardation but who appears, at age 2 years 8 months, to be developing normally mentally. There is a small number of reports of mildly affected cases of r(21), and of some with an apparently completely normal phenotype. We presume a structural and functional cytogenetic heterogeneity underlies the observed phenotypic heterogeneity in the ring 21 spectrum.     

Distribution of immunity to pertussis in the population of England and Wales.

This paper presents three different methods of estimating the number and age distribution of individuals susceptible to pertussis in England and Wales. The first approach is an extrapolation from data in the prevaccine era, the second is based upon theoretical consideration of the transmission dynamics of pertussis, and the third is a detailed cohort analysis of available notification and vaccination data. Each of these analyses suggests that the total number of people susceptible to pertussis infection in England and Wales has remained at 3-4 million for the past 40 years, despite the increase and changes in numbers vaccinated. The effect of vaccination has been to reduce the incidence of infection and disease, but not to reduce the number of susceptibles. These findings, which are consistent with ''mass action theory'', could be tested by an appropriately designed seroepidemiological survey.     

Nonpalpable breast lesions: diagnosis with slightly overpenetrated screen-film mammography and hook wire-directed biopsy in 1,014 cases

Slightly overpenetrated screen-film mammography and hook wire-directed localization were used in 1,014 breast biopsies performed for nonpalpable, mammographically detected breast abnormalities. One lymphoma and 205 breast cancers (20%) were found; 115 breast cancers (56%) were noninvasive, and 90 (44%) were invasive. Mastectomy was performed in 69 breast cancers (34%); 136 (66%) were treated conservatively, 28 with biopsy only and 108 with lumpectomy, node dissection, and radiation therapy. All patients with noninvasive breast cancers treated with axillary dissection had uninvolved lymph nodes. Of the 90 invasive breast cancers, six (7%) had metastases to axillary nodes, which, to the authors' knowledge, is lower than percentages reported in other studies of wire-directed breast biopsies. The authors believe that the slightly overpenetrated technique is a valuable adjunct to screen-film mammography.     

An interhemispheric comparison of auditory evoked responses to consonant-vowel stimuli

Evoked responses to monaurally-presented voiced stop consonants (ba, da, ga) were recorded from 18 right-handed adult male subjects. Stimulation of the ear contralateral to the active recording electrode produced significantly larger AERs than did ipsilateral ear stimulation. No significant latency differences were found between contralateral and ipsilateral ear stimulation. “Hemispheric effects” (i.e. differences between right and left sides of the scalp in addition to those produced by ear-pathway effects described above) could not be demonstrated in latency or amplitude characteristics of the AER.     

An analysis of medical device-related errors: prevalence and possible solutions

The UK and USA are currently undergoing a period of considerable change in their attitude towards medical error and their understanding of its causes and magnitude. In both countries, with increasing rapidity, a disturbing situation is being revealed. This paper presents the results of an investigation into medical errors in the UK and the USA, and focuses in particular on the magnitude and causes of errors when using medical devices. Contrary to the traditional approach of blaming users, it is suggested here that many such errors are caused partly by poor device design, which fails to account adequately for the needs of users. In response, this paper also discusses the basics of a Human Factors Engineering (HFE) approach as a step towards overcoming this problem and offers a challenge to device users and design companies (manufacturers) to follow HFE principles in order to improve the efficiency of operation and reduce errors during device use.     

Regulatory CD25+ T cells in human kidney transplant recipients

Recent evidence suggests that a population of professional regulatory cells, which limit immune responsiveness, exist in rodents and healthy human subjects. However, their role in disease states remains unclear. A proportion of renal transplant recipients do not demonstrate in vitro reactivity toward their mismatched donor-derived HLA-DR antigens; it was therefore hypothesized that this may be due to such regulatory cells. A cohort of 23 renal transplant recipients was studied at a single institution. In patients with no history of acute rejection, 6 (40%) of 15 demonstrated regulation toward the mismatched HLA-DR allopeptides by CD25(+) cells. By contrast, only one (12.5%) in eight of those with a history of acute rejection demonstrated regulation. Interestingly, if the patient assays were stratified according to initial in vitro immune responsiveness toward the mismatched allopeptides, 8 (47.1%) of 17 of patient assays with low allopeptide responsiveness (alloreactive T cell frequencies less than 60/million) demonstrated regulation of indirect pathway alloresponses by CD25(+) cells, whereas 0 of 8 with higher responses (frequencies greater than 60/million) demonstrated no such regulation (P < 0.05 by chi(2) test). The regulatory cells are present in the circulation as early as 3 mo after transplantation and persist for a number of years, despite conventional immunosuppression. Furthermore, induction treatment with anti-IL-2R mAb did not prevent the development of these regulatory CD25(+) cells. Data from two patients suggest that these cells may also play a role in preventing epitope shifting, implicated in the ongoing immune activation contributing to chronic rejection, and that loss of regulation in a given patient may precede an episode of rejection.