New stand magnifiers do not meet rated levels of performance

A new range of stand magnifiers has been released by the COIL company in the United Kingdom. Examination of these magnifiers reveals that they fail to deliver the rated magnifications labelled prominently on the appliances, as a result of the manufacturer's conformance with the requirements of the German DIN standard and the use of back vertex power (F'_v) rather than equivalent dioptric power (F_m) of the magnifier. In this study we provide information on the optometric parameters of these new stand magnifiers that will assist the more accurate specification of improvements in vision expected from their use.     

Profile of an adolescent problem drinker

A study was conducted to determine what sociocultural and demographic variables can be used to identify potential problem drinkers among adolescents in middle school and high school. Three thousand seventeen students were administered an in-depth questionnaire regarding their knowledge, attitudes, and behavior toward the use of alcohol. Twenty schools in six school districts in the two-state area of Georgia and South Carolina participated in the study. A number of analyses indicated that the student heavy drinker was most typically male, white, and between the ages of 14 and 15 years with an above average knowledge about alcohol and liberal attitudes toward alcohol use. The adolescent heavy drinker is more likely to have parents and best friends who are heavy drinkers, to have had his first encounter with alcohol at an early age, to drink with friends his own age, and to feel that almost all of his friends drink. Results of this study can be used by family physicians in the management of potential alcohol abusers. Early recognition and intervention by the family physician may help to reduce the alarming number of adolescents who are struggling with problems related to alcohol.     

Pheochromocytoma and paraganglioma: comparison of MR imaging with CT and I-131 MIBG scintigraphy

To ascertain the magnetic resonance (MR) imaging characteristics of pheochromocytomas and paragangliomas and to compare MR with computed tomography (CT) and iodine-131 metaiodobenzylguanidine (I-131 MIBG), 19 patients (18 with pheochromocytomas, one with a paraganglioma) were studied. The 18 patients with pheochromocytomas had had positive findings with I-131 MIBG scintigraphy. Abdominal pheochromocytomas were generally hypointense compared with normal liver on T1-weighted MR images and extremely hyperintense on T2-weighted MR images. MR imaging was preferable to CT in the evaluation of primary pheochromocytomas due to superior tissue characterization, particularly in the patient with hypertension and borderline catecholamine levels. For patients with recurrent or metastatic disease, the data suggest that I-131 MIBG scintigraphy is the examination of choice.     

Chaperonin-mediated assembly of wild-type and mutant subunits of human propionyl-CoA carboxylase expressed in Escherichia coli

We developed a bacterial expression system for the human alpha and beta cDNAs of propionyl-CoA carboxylase (PCC). These cDNAs (less the putative mitochondrial matrix targeting presequences) were co-expressed in Escherichia coli on one plasmid vector with each cDNA having its own IPTG-inducible promoter. Only negligible amounts of active PCC were measured despite the presence of both alpha and beta subunits as indicated by Western blot analysis and the almost complete biotinylation of the alpha subunit. Co-expression of this plasmid with a second plasmid vector over-expressing the E. coli chaperonin proteins, groES and groEL, resulted in a several hundred-fold increase in PCC specific activity, to a level comparable with that found in crude human liver extracts. PCC was partially purified on monomeric avidin affinity resin and the presence of both alpha and beta subunits was demonstrated, thereby confirming the assembly of both subunits into an active enzyme. Deficiency of either alpha PCC or beta PCC results in propionic acidemia, an autosomal recessive disorder. We used this expression system to characterize one missense mutation previously described in five Japanese alleles, namely C1283T (Thr428lle) in beta PCC. This mutation, when expressed in E.coli under the same conditions as that of wild-type PCC, had null activity, despite the presence of assembled alpha PCC and beta PCC subunits. This bacterial expression system can be useful for analysis of either alpha PCC or beta PCC mutations. Our findings indicated that the groES and groEL chaperonin proteins were essential for folding and assembly of the human PCC heteromeric subunits.      

Induction of mosquitocidal activity in mice immunized with Anopheles gambiae midgut cDNA

Vaccines that induce mosquito-killing (mosquitocidal) activity could substantially reduce the transmission of certain mosquito-borne diseases, especially vaccines against African malaria vectors, such as the mosquito Anopheles gambiae. To generate and characterize antimosquito immunity we immunized groups of mice with two individual A. gambiae midgut cDNAs, Ag-Aper1 (a secreted peritrophic matrix protein) and AgMuc1 (a midgut-bound mucin), and an A. gambiae midgut cDNA library from blood-fed mosquitoes. We observed significantly increased mortality among mosquitoes that fed on either the AgMuc1- or the cDNA library-immunized mice compared to that of controls, but no differences were observed among those fed on Ag-Aper1-immunized mice. Analysis of the humoral and cellular immune responses from mice showed that the induced mosquitocidal effect was associated with immune profiles characterized by elevated tumor necrosis factor alpha and gamma interferon cytokine levels and very low antibody titers. Furthermore, an additional immunization of cDNA library-immunized mice with midgut protein shifted immunity toward a Th2-type immune response, characterized by elevated antibody titers and high interleukin-5 and interleukin-10 cytokine levels; importantly, mosquitoes feeding on these mice exhibited no undue mortality. Finally, when immune sera was ingested by mosquitoes through a membrane feeder, no effect on mosquito mortality was observed, indicating that serum factors alone were not responsible for the mosquitocidal effect. Our results demonstrate that mosquitocidal immunity in mice can be consistently generated by midgut cDNA immunization and suggest this cDNA-induced mosquitocidal immunity is cell mediated.     

Growth, morbidity, and mortality in a cohort of institutionalized HIV-1-infected African children

OBJECTIVE: As a result of the HIV epidemic in Africa, much debate exists on whether institutionalized compared with community-based care provides optimum management of infected children. Previous reports calculated 89% mortality by age 3 years among outpatients in Malawi. No similar data are available for infected children in institutionalized care. We characterized patterns of morbidity and mortality among HIV-1-infected children residing at an orphanage in Nairobi. METHODS: Medical records for 174 children followed over 5 years were reviewed. Mortality was analyzed by Kaplan-Meier methods with adjustment to account for survival in the community before admission. Anthropometric indices were calculated to include mean z scores for weight for length and length for age. Low indices reflected wasting and stunting. Opportunistic infections were documented. RESULTS: Of 174 children, 64 had died. Survival was 70% at age 3 years. Morbidity included recurrent respiratory tract infections, gastroenteritis, parotitis, and lymphoid interstitial pneumonitis. No new cases of tuberculosis disease were noted after admission. Mean z scores for length for age suggested overall stunting (z = -1.65). Wasting was not observed (z = -0.39). CONCLUSION: The optimal form of care for HIV-infected children in resource-poor settings may be the development of similar homes. Absence of tuberculosis disease in long-standing residents may have contributed to improved survival. Stunting in the absence of wasting implied that growth was compromised by opportunistic infections and other cofactors.     

Diagnosis of breast cancer using elastic-scattering spectroscopy: preliminary clinical results

We report on the first stages of a clinical study designed to test elastic-scattering spectroscopy, mediated by fiberoptic probes, for three specific clinical applications in breast-tissue diagnosis: (1) a transdermal-needle (interstitial) measurement for instant diagnosis with minimal invasiveness similar to fine-needle aspiration but with sensitivity to a larger tissue volume, (2) a hand-held diagnostic probe for use in assessing tumor/resection margins during open surgery, and (3) use of the same probe for real-time assessment of the "sentinel" node during surgery to determine the presence or absence of tumor (metastatic). Preliminary results from in vivo measurements on 31 women are encouraging. Optical spectra were measured on 72 histology sites in breast tissue, and 54 histology sites in sentinel nodes. Two different artificial intelligence methods of spectral classification were studied. Artificial neural networks yielded sensitivities of 69% and 58%, and specificities of 85% and 93%, for breast tissue and sentinel nodes, respectively. Hierarchical cluster analysis yielded sensitivities of 67% and 91%, and specificities of 79% and 77%, for breast tissue and sentinel nodes, respectively. These values are expected to improve as the data sets continue to grow and more sophisticated data preprocessing is employed. The study will enroll up to 400 patients over the next two years.