It's the law. What is?

The New York State Partner Notification law is expected to go into effect in late spring or summer 1999. Residents who choose to be tested for HIV and test positive are required to have their names reported to the State Department of Health. The second part, requesting the names of all recent sexual and needle-sharing partners, is voluntary. Efforts will be made to inform partners who may have been exposed to HIV. All names will be kept in confidence within the department. Persons tested at anonymous testing sites or those who tested positive before the law was passed are exempt, but if medical care involving HIV is sought, the names of HIV-positive people will be reported. Medical practitioners are required to report any "known contacts" listed on any form viewed by the practitioner; for example, a spouse listed on an insurance form would be a known contact. Contact information for two AIDS policy groups is provided.     

What is the most relevant standard of success in assisted reproduction? The importance of informed choice

Whilst there is a need to emphasize the birth rates of healthy infants when reporting success rates following infertility treatment, is 'the singleton term gestation per cycle started' the most appropriate measure? Although there are many ways to measure the efficacy of medical intervention, none of these exclude from the 'successes' those in whom complications have occurred. The safe delivery of healthy twins at term, while possibly not the ideal outcome, should still be regarded as a treatment success. Although multiple pregnancy, in particular high order multiple pregnancy, continues to be a major problem associated with assisted reproductive treatments and also with ovulation induction, appropriate counselling concerning the risks of twin and triplet pregnancies will allow couples to make informed choices and allow clinicians to continue to individualize treatment plans.     

What is the importance of the immunological synapse?

The immunological synapse (IS) has proved to be a stimulating concept, particularly in provoking discussion on the similarity of intercellular communication controlling disparate biological processes. Recent studies have clarified some of the underlying molecular mechanisms and functions of the IS. For both T cells and natural killer (NK) cells, assembly of the IS can be described in stages with distinct cytoskeletal requirements. Functions of the IS vary with circumstance and include directing secretion and integrating positive and negative signals to determine the extent of response.     

What is the MHC?

The major histocompatibility complex (MHC) has been studied for many years, but it still continues to puzzle geneticists and immunologists alike. Nevertheless, the study of MHC evolution is providing insights into some of its enigmas, and these were discussed at a recent meeting.¹     

What is the contents of the magic draft IVIg?

Intravenous immunoglobulins (IVIg) consist of IgG concentrated from pooled plasma of numerous donors. Their contents is variable, depending in part on the method of preparation. Natural antibodies and natural autoantibodies are prominent in these preparations and their function. Among these, are the idiotype (Id)/anti-Id dimers. Attention has recently been paid to Fc-gamma receptors and sialylation of the IgG from IVIg.     

What is the most relevant standard of success in assisted reproduction? Assessing the BESST index for reproduction treatment

It has been proposed that use of performance indicators for assisted reproduction treatment (ART) should be revised to better reflect the burden of treatment endured by a couple, and to place greater emphasis on the desired outcome of healthy babies. Recently, the BESST (birth emphasizing a successful singleton at term) score as a routine measurement for use in ART has been suggested. We applied the BESST index to a sample of ART patients and found that the BESST score was sensitive to the effects of patient age and extremes in the number of embryos transferred. However, the statistical properties of the index placed great weight on the effective implantation rate, which when applied to a time series in which implantation rates were improving, showed BESST scores to increase simultaneously with multiple pregnancy rates. This limits the completeness of the summary score as an expression of benefits compared to risks. A modified BESST index, not including cycles of initiated treatment as a denominator, indicated that the ART births contained a substantially lower proportion of BESST babies when compared to the entire population of births.     

What fraction of the human genome is functional?

Many evolutionary studies over the past decade have estimated α(sel), the proportion of all nucleotides in the human genome that are subject to purifying selection because of their biological function. Most of these studies have estimated the nucleotide substitution rates from genome sequence alignments across many diverse mammals. Some α(sel) estimates will be affected by the heterogeneity of substitution rates in neutral sequence across the genome. Most will also be inaccurate if change in the functional sequence repertoire occurs rapidly relative to the separation of lineages that are being compared. Evidence gathered from both evolutionary and experimental analyses now indicate that rates of "turnover" of functional, predominantly noncoding, sequence are, indeed, high. They are sufficiently high that an estimated 50% of mouse constrained noncoding sequence is predicted not to be shared with rat, a closely related rodent. The rapidity of turnover results in, at least, a twofold underestimate of α(sel) by analyses that measure constraint across the eutherian phylogeny. Approaches that take account of turnover estimate that the steady-state value of α(sel) lies between 10% and 15%. Experimental studies corroborate the predicted rates of loss and gain of noncoding functional sites. These studies show the limitations inherent in the use of deep sequence conservation for identifying functional sequence. Experimental investigations focusing on lineage-specific, noncoding, and functional sequence are now essential if we are to appreciate the complete functional repertoire of the human genome.     

What is the true location of Jacoby's line?

We investigated 60 cadavers to examine the accurate location of conus medullaris, lower end of dura mater, and intercrestal line (Jacoby's line). Jacoby's line was established using the method described by Jacoby GW (1899). Then the intersection of this line and vertical line through the spinous processes was marked by a fine nail. After a laminectomy was performed to expose the spinal cord, spinal level of the conus medullaris, the lower end of dura mater, and Jacoby's line were examined, and marked and recorded these locations of nailing. In 2 of 48 cases (2.1%), Jacoby's line passed through the level superior to 3rd lumber vertebra (L3). The Conus medullaris was at the level beneath L3 in 2 of 57 cases (3.5%). And lower end of dura mater was located beneath the superior margin of S3 in 1 of 28 cases (3.6%). When Jacoby's line is used as a guide-point, the site for subarachnoid puncture is established in the L3-4 interspinous space. But when we consider the risk of spinal cord injury cannot be completely excluded, in case that conus medullaris is located inferior to L3 in 3.5% of cases. Conseqently, it should be important to avoid performing subarachnoid puncture at L2-3 or higher lumbar vertebral level especially in the elderly.     

What is the effect of fasting on the lifespan of neurons?

Medical advancements have increased life expectancy but have consequently increased the incidence of age-related disease. Fasting or dietary restriction (DR) can help prevent these via anti-ageing effects; however, these effects in neurons are less well characterized. Here, a series of animal and human studies of the effects of DR on the structural and functional integrity of neurons and the underlying mechanisms are analyzed. DR improves the integrity of animal neurons via a wide range of possible mechanisms including changes in metabolism, oxidative damage, stress responses, growth factors, and gene expression. These mechanisms are extensively interlinked and point to an optimum range of calorie intake, above calorie deprivation and below burdensome calorie excess. Human studies also suggest that DR improves neuron integrity; however, due to ethical and methodological limitations, the most conclusive data on DR hinge upon on-going life-long monkey experiments. Rather than developing pharmacological mimetics of DR, our focus should be on educating the public about DR in order to minimize age-related disease.     

What is the global burden of visual impairment?

Background

No efficacy studies of influenza vaccination given to GPs have yet been published. Therefore, our purpose was to assess the effect of an inactivated influenza vaccine given to GPs on the rate of clinical respiratory tract infections (RTIs) and proven influenza cases (influenza positive nose and throat swabs and a 4-fold titre rise), while adjusting for important covariates.

Methods

In a controlled trial during two consecutive winter periods (2002–2003 and 2003–2004) we compared (77 and 100) vaccinated with (45 and 40) unvaccinated GPs working in Flanders, Belgium. Influenza antibodies were measured immediately prior to and 3–5 weeks after vaccination, as well as after the influenza epidemic. During the influenza epidemic, GPs had to record their contact with influenza cases and their own RTI symptoms every day. If they became ill, the GPs had to take nose and throat swabs during the first 4 days. We performed a multivariate regression analysis for covariates using Generalized Estimating Equations.

Results

One half of the GPs (vaccinated or not) developed an RTI during the 2 influenza epidemics. During the two influenza periods, 8.6% of the vaccinated and 14.7% of the unvaccinated GPs had positive swabs for influenza (RR: 0.59; 95%CI: 0.28 – 1.24). Multivariate analysis revealed that influenza vaccination prevented RTIs and swab-positive influenza only among young GPs (ORadj: 0.35; 95%CI: 0.13 – 0.96 and 0.1; 0.01 – 0.75 respectively for 30-year-old GPs). Independent of vaccination, a low basic antibody titre against influenza (ORadj 0.57; 95%CI: 0.37 – 0.89) and the presence of influenza cases in the family (ORadj 9.24; 95%CI: 2.91 – 29) were highly predictive of an episode of swab-positive influenza.

Conclusion

Influenza vaccination was shown to protect against proven influenza among young GPs. GPs, vaccinated or not, who are very vulnerable to influenza are those who have a low basic immunity against influenza and, in particular, those who have family members who develop influenza.     

What is the arcuate eminence?

A study was made of 100 homogeneous CT scans of the petrous part of the temporal bone to determine whether or not the arcuate eminence (AE) is a good landmark for the superior semicircular canal (SSCC) in the suprapetrous approach to the internal acoustic meatus which is used in the extirpation of acoustic neuromas. Direct measurements were made on consecutive coronal sections, 1 mm thick. The AE was absent from the petrous surface in 15% of cases. It corresponded to the relief of the SSCC in 37% of cases; laterally, however, it was separated from the petrous cortex by bone whose thickness varied from 0.5 to 5 mm. Finally, in 48% of cases, the AE was not a good landmark for the canal although nonetheless it participated in the development of this bulge in 46% of cases, always lying towards the medial border of the pneumatized eminence. In addition, study of the coronal sections with MRI allowed us to confirm that the AE does not routinely correspond to the imprint of a temporal sulcus. The AE, whose presence on the petrous surface is due to the combined effects of the SSCC, the air cells of the petrous part of the temporal bone and the temporal sulci, is only a good guide to the SSCC in 37% of cases and should not be considered as a reliable surgical landmark.