Elimination and minimization of the spherical aberration of intraocular lenses in high myopia

By applying Seidel aberration theory we have studied the spherical aberration of intraocular lenses in place ( S _IL), and the total spherical aberration of pseudophakic eyes ( S _IT). The optimum lens shapes for zero S _IL and S _IT or for minimum S _IL and S _IT of 12 schematic, highly myopic eyes were investigated. When the power required for emmetropization is positive, the total Seidel spherical aberration of the whole eye cannot be zero but can only be minimized. If the power of the intraocular lens is negative, the total Seidel spherical aberration of the whole eye can be made zero, and one of the optimum lens shapes would be meniscus with the convex surface towards the retina. In addition to improving the quality of the image, the lens has advantages from the physiological point of view, since it helps to maintain the structure of the eye.     

Diffuse Axonal Injury (DAI) is not Associated with Elevated Intracranial Pressure (ICP)

Summary Objective. Traditionally, intracranial pressure (ICP) monitoring has been utilized in all patients with severe head injury (Glasgow coma score of 3–8). Ventriculostomy placement, however, does carry a 4 to 10 percent complication rate consisting mostly of hematoma and infection. The authors propose that a subgroup of patients presenting with severe head trauma and diffuse axonal injury without associated mass lesion, do not need ICP monitoring. Additionally, the monitoring data from ICP, MAP, and CPP for a comparison severe head injury group, and subgroups of DAI would be presented. Materials and methods. Thirty-six patients sustaining blunt head trauma and fitting our strict clinical and radiographic diagnosis of DAI were enrolled in our study. Inclusion criteria were severe head injury patients who did not regain consciousness after the initial impact, and whose CT scan demonstrated characteristic punctate hemorrhages of <10 mm diameter at the greywhite junction, basal ganglia, corpus callosum, upper brainstem, or a combination of the above. Patients with significant mass lesions and documented anoxia were excluded. Their intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were compared to a control group of 36 consecutive patients with severe non-penetrating non-operative head injury, using the Analysis for Variance method. Results. Eighteen (50.0%), six (16.7%), and twelve (33.3%) patients had types I, II, and III DAI, respectively. The admission Glasgow Coma Score (GCS) was higher for types I and II than for type III DAI. ICP was monitored from 23 to 165 hours, with a mean ICP for 36 patients of 11.70 mmHg (SEM=75) and a range from 4.3 to 17.3 mmHg. Of all ICP recordings, of which 89.7% (2421/2698) were ≤20 mmHg. Average mean arterial pressure (MAP) was 96.08 mmHg (SEM=1.69), and 94.6% (2038/2154) of all MAP readings were greater than 80 mmHg. Average cerebral perfusion pressure (CPP) was 85.16 mmHg (SEM=1.68), and 90.1% (1941/2154) of all CPP readings were greater than 70 mmHg. This is compared to the control group mean ICP, MAP, and CPP of 16.84 mmHg (p=0.000021), 92.80 mmHg (p=0.18), and 76.49 mmHg (p=0.0012). No treatment for sustained elevated ICP>20 mmHg was needed for DAI patients except in two; one with extensive intraventricular and subarachnoid hemorrhage who developed communicating hydrocephalus, and another with ventriculitis requiring intrathecal and intravenous antibiotic treatments. Two complications, one from a catheter tract hematoma, and another with Staph epidermidis ventriculitis, were encountered. All patients, except type III DAI, generally demonstrated marked clinical improvement with time. The outcome, as measured by Glasgow Coma Score (GCS) and Glasgow Outcome Score (GOS) was similarly better with types I and II than type III DAI. Conclusion. The authors conclude that ICP elevation in DAI patients without associated mass lesions is not as prevalent as other severe head injured patients, therefore ICP monitoring may not be as critical. The presence of an ICP monitoring device may contribute to increased morbidity. Of key importance, however, is an accurate clinical history and interpretation of the CT scan.     

Usefulness of different myocardial sampling zones for the postmortem diagnosis of myocardial infarction

Summary The diagnosis of myocardial infarction requires the use of a group of tests that are very efficient, quick and inexpensive. Another important consideration is the choice of myocardial sampling zones, especially in cases of differential diagnosis between a cardiac injury secondary to a trauma or violent asphyxia and others, secondary to myocardial infarction. The aim of this work was to choose, through discriminant analysis, the most useful zones of cardiac tissue for the quantification of free fatty acids and free carnitine and for the performance of the K/Na quotient, as biochemical parameters for the postmortem diagnosis of myocardial infarction. According to the discriminant analysis performed, seven zones of cardiac tissue are necessary to achieve a differential diagnosis among myocardial infarction, other natural deaths, and violent deaths with a 71.9% efficacy. Greater diagnostic efficacy was found (78.1%) for differentiating between natural deaths and violent deaths. Offprint requests to: E. Lachica     

Effect of acute insulin administration on biliary lipid secretion by the diabetic rat.

The insulin-deficient state induces profound changes in bile formation. The present work was to test the effect of acute insulin administration on lipid secretion into bile in diabetic rats. Diabetes was induced by streptozotocin injection (6 mg/100 g body-weight, i.p., 6 days before the experiments). Bile formation was stimulated by taurocholate infusion (0.5 mumol/min/100 g body-weight). Intravenous administration of insulin (bolus: 100 mU/100 g body-weight, plus infusion: 5 mU/min/100 g body-weight) induced choleresis accompanied by a slight and transient enhancement in bile acid output which was similar to that found in lecithin and cholesterol output in the control group. However, insulin induced a rapid and significant (P less than 0.05) reduction in biliary lipid output in the diabetic rats. These results suggest that insulin may play an important role in mechanisms other than synthesis involved in the supply of biliary lipids towards the canaliculi.     

Transmission of HIV-1 infection between trophoblast placental cells and T-cells take place via an LFA-1-mediated cell to cell contact

HIV-1 vertical transmission is thought to mainly take place by virus crossing the placental barrier. However, the mechanism by which HIV-1-infects placental cells remains to be elucidated. We have found that purified cytotrophoblasts as well as trophoblastic cell lines are susceptible to infection by different HIV-1 isolates as detected by DNA-PCR and release of infectious virus, although with very low efficiency. Purified trophoblast or trophoblastic cell lines express low levels of chemokine receptors CCR-5 and CXCR-4 but not CD4 on the cell surface. To test if those molecules were used as receptors for HIV-1 infection, placental cells were pretreated with antibodies to CD4, CC-chemokines, C-X-C chemokines. None of those treatments inhibited HIV-1 infection. In contrast, we have found that HIV-1 infection of placental cells was increased in cocultures of infected T-cell blasts and placental cells. More interestingly, antibodies to beta(2) integrins and to LFA-1 were able to significantly block infection of placental cells. Cell surface expression of ICAM-1, an adhesion molecule involved in attachment of leukocytes to placenta, was upregulated in HIV-1-infected placental cells. Placental cells were able to transfer HIV-1 infection to T-cell blasts. This transmission required cell to cell contact and was also inhibited by anti-LFA-1 antibodies. In summary our results suggest that placental trophoblast could be infected by HIV-1 by a mechanism involving T cell to placental contact. Moreover, placental infection enhanced ICAM-1 expression and leukocyte adherence, an event which was required to transfer HIV-1 infection to T cells. This provides an explanation of the virus passing through the placental barrier during in utero HIV-1 vertical transmission.     

Detection of infectious human immunodeficiency virus type 1 in female genital secretions by a short-term culture method

Infectious human immunodeficiency virus type 1 (HIV-1) is difficult to detect in female genital secretions by standard virus culture techniques. To improve detection of cell-free HIV-1 in female genital secretions, we adapted a short-term assay that uses the multinuclear-activation galactosidase indicator (MAGI) assay. When vaginal lavages from HIV-1-infected women were tested with the adapted MAGI assay, 25 (64%) of 39 lavages with detectable, cell-free HIV-1 RNA were shown to have infectious virus. No infectious virus was found in 10 vaginal lavages from HIV-1-infected women with undetectable vaginal viral loads. Significantly (P < 0.01) more lavages from HIV-1-infected women tested positive for infectious virus by the MAGI assay than by standard peripheral blood mononuclear cell (PBMC) coculture, which detected infectious virus in only 6 (17%) of 35 vaginal lavages. Lavages with viral loads of >10,000 copies per lavage yielded significantly (P < 0.01) more positive cultures than those with <10,000 copies by using the MAGI assay. Detection of infectious HIV-1 in vaginal lavages was not associated with the presence of genital tract infections or CD4(+)-T-cell counts. However, although the results were not significant (P = 0.08), the MAGI assay detected infectious virus from more vaginal lavages at a vaginal pH of >/=4.5 than at a pH of <4.5. These results indicate that the MAGI assay is more sensitive than PBMC culture methods for detecting infectious virus in female genital secretions. Accurate measurements of infectious virus in genital secretions will improve studies that evaluate sexual transmission of HIV-1.     

Cavitary pneumonia in an AIDS patient caused by an unusual Bordetella bronchiseptica variant producing reduced amounts of pertactin and other major antigens

Although Bordetella bronchiseptica can infect and colonize immunocompromised humans, its role as a primary pathogen in pneumonia and other respiratory processes affecting those patients remains controversial. A case of cavitary pneumonia caused by B. bronchiseptica in an AIDS patient is presented, and the basis of the seemingly enhanced pathogenic potential of this isolate (designated 814) is investigated. B. bronchiseptica was the only microorganism recovered from sputum, bronchoalveolar lavage fluid, and samples taken through the protected brush catheter. Unlike previous work reporting the involvement of B. bronchiseptica in cases of pneumonia, antibiotic treatment selected on the basis of in vitro antibacterial activity resulted in clearance of the infection and resolution of the pulmonary infiltrate. Although isolate 814 produced reduced amounts of several major antigens including at least one Bvg-activated factor (pertactin), the molecular basis of this deficiency was found to be BvgAS independent since the defect persisted after the bvgAS locus of isolate 814 was replaced with a wild-type bvgAS allele. Despite its prominent phenotype, isolate 814 displayed only a modest yet a significant deficiency in its ability to colonize the respiratory tracts of immunocompetent rats at an early time point. Interestingly, the antibody response elicited by isolate 814 in these animals was almost undetectable. We propose that isolate 814 may be more virulent in immunocompromised patients due, at least in part, to its innate ability to produce low amounts of immunogenic factors which may be required at only normal levels for the interaction of this pathogen with its immunocompetent natural hosts.     

Comparative evaluation of the new version of the INNO-LiPA Mycobacteria and genotype Mycobacterium assays for identification of Mycobacterium species from MB/BacT liquid cultures artificially inoculated with Mycobacterial strains

The performance of two DNA line probe assays, a new version of INNO-LiPA Mycobacteria (Innogenetics, Ghent, Belgium) and the GenoType Mycobacterium (Hain Diagnostika, Nehren, Germany), were evaluated for identification of mycobacterial species isolated from liquid cultures. Both tests are based on a PCR technique and designed for simultaneous identification of different mycobacterial species by reverse hybridization and line probe technology. The INNO-LiPA Mycobacteria v2 targeting the 16S-23S rRNA gene spacer region was developed for the simultaneous identification of 16 different mycobacterial species. The GenoType Mycobacterium, which targets the 23S rRNA gene, allows simultaneous identification of 13 mycobacterial species. Both tests were evaluated on 110 mycobacterial strains belonging to 22 different mycobacterial species (20 reference strains, 83 clinical strains, and 4 Mycobacterium kansasii strains isolated from tap water) that were previously inoculated into MB/BacT bottles. The sensitivity of both methods, defined as the number of positive results obtained with the Mycobacterium genus probe together with an interpretable result on the number of samples tested was 110 of 110 (100%) for INNO-LiPA and 102 of 110 (92.7%) for GenoType. For samples with interpretable results, INNO-LiPA was able to correctly identify 109 of 110 samples (99.1%), whereas the GenoType correctly identified 100 of 102 samples (98.0%). Both tests were easy to perform, rapid, and reliable when applied to mycobacterial identification directly from MB/BacT bottles.