[Perinatal health indicators in 2001 and its evolution since 1994. Results from the Audipog sentinel network]

The AUDIPOG association (Association of Users of Computerized Files in Perinatalogy, Obstetrics and Gynaecology) proposed in 1994 the setting up of the Sentinel Network, including voluntary public and private maternity units from all areas in France. Each year, every member sends individual data related to a sample of births to the AUDIPOG Network. Today, the common database comprises 95,000 births collected during one month by all members of the network. Thanks to a standardization procedure, the perinatal health indicators, obtained from the common database, are valid estimations at the national level. The results of a given year are published at the beginning of the following year, providing a continual survey of perinatal indicators in France. Since the regionalization of perinatal services, a common perinatal information system is of great importance for a continual survey of perinatal health indicators and assessment of medical practices. Among the most important results of this perinatal network, we observed an increase in the rate of multiple pregnancies from 3.5% of births in 1998 to 4.2% in 2001. The increase of multiple births seems to be related to a lower maternal age in case of procreative medical assistance. As a consequence, the rate of preterm births was also increased, resulting in 7.2% of all births. In another section a regular increase in the rate of cesarean sections, from 16.3% in 1999 to 17.6% was observed in 2001. Cesarean sections before labour are chiefly concerned. From 1999, each member of the AUDIPOG network is given access to the entire common database, on the Internet AUDIPOG site, in order to describe medical practices when faced with a particular clinical situation of interest. This access to the common database aids self-assessment of medical practices and quality improvement (http://audipog.inserm.fr).

[How to choose in practice a model to describe the geographic variation of cancer incidence? Example of gastrointestinal cancers from Côte-d'Or]

BACKGROUNDS

In epidemiology, standardized Incidence Ratio (SIR) can have large variance and it is then difficult to distinguish random fluctuations from real spatial variations when describing spatial variations in the rate of cancer. In this context, hierarchical model produce smoothed relative risks estimations helpful for solving this problem. The main advantage of these methods is to combine information of each geographical area with that obtained from prior assumption on the similarity between geographical sub-units. Nevertheless different assumptions produce different geographical maps of incidence of cancer, and the purpose of the present study was the development of a strategy to choose the most satisfactory description of the incidence of digestive cancer in a French department.

METHODS

The strategy to choose the most satisfactory geographical map depends on the following criteria: variability between geographical sub-units, auto-correlation, and variability within geographical sub-unit. These criteria have been estimated from observed data for each site of cancer.

RESULTS

This strategy was applied to digestive tract cancers diagnosed between 1976 and 1997 in the department of Côte-d'Or, France. High-risk areas were often detected in the urban zone of the department, but without autocorrelation in most cases.

CONCLUSION

This strategy permitted to describe cancers in very small areas, avoiding to a large extent the danger of focusing on falsely positive high-risk areas.

International tobacco control: a focus group study of U.S. anti-tobacco activists

Massachusetts tobacco control activists participated in focus groups to explore their knowledge, beliefs, and attitudes regarding international tobacco control. Initially, each of three focus groups ranked this issue at or near the bottom of important tobacco control issues. Participants ranked ten message concepts for their ability to motivate politically active Americans to contact a government representative about international tobacco issues. The top four message concepts dealt with deliberate marketing of cigarettes to children, dramatic increases in global mortality due to smoking, American hypocrisy in being the world's largest tobacco exporter, and use of overseas profits to finance youth-oriented marketing in the U.S. The rankings revealed little initial concern about U.S. diplomatic pressure to force foreign nations to open up their markets to American tobacco products. Yet during the subsequent discussion this was among the message concepts the generated the most outrage. This suggests that international tobacco control issues would resonate among U.S. opinion leaders once the facts were presented to them through a media advocacy campaign.

Albumin loss in on-line hemodiafiltration

BACKGROUND

Based on the increased hydraulic permeability of the new high permeability polyethersulfone membrane, DIAPES HF-800, we investigated the kinetics and handling of albumin in high volume on-line hemodiafiltration (HDF).

METHODS

Seven patients on predilutional HDF were studied in two consecutive sessions. Blood flow rate and transmembrane pressure were continuously monitored. Spent dialysate was spilled at 20 ml/h every hour. Albumin was measured in blood and dialysate by immunonephelometry. Albumin and proteins adsorbed onto the dialyzer membrane were eluted after treatment with Triton X. Ultrafiltrates collected at 1 and 2 hours of treatment were pooled from different patients and incubated for 24 hours at 37 degrees C with bovine serum albumin (BSA). Total sulphydryl groups were evaluated using Ellmann's reagent [5, 5'-dithio-bis(2-nitrobenzoic acid)].

RESULTS

In all 7 patients, the total loss of albumin was 3.99 +/- 1.81 g, ranging between 1.09 and 6.82 g/session. Most albumin loss occurred in the first 60 min of pre-dilutional hemodiafiltration (1.92+0.83 g). There was no correlation between transmembrane pressure, urea clearance and the loss of albumin. Plasma water urea clearance values were stable over the treatment (234 +/- 14.3 ml/min). Plasma albumin concentration did not decrease during HDF sessions. Albumin adsorbed onto the dialyzers was 0.7 +/- 1.6 mg but the total amount of adsorbed proteins was much higher (130 + 90 mg). In addition, the ultrafiltrate collected during HDF sessions was able to induce oxidation of bovine serum albumin as measured by total protein sulfhydryl groups: bovine serum albumin incubated in the presence of ultrafiltrate collected at 1 hour had a sulfhydryl loss of 56.3 +/- 5.7% (p < 0.0001 vs control), and bovine serum albumin incubated with ultrafiltrate collected at 2 hours had a loss of 67.5 +/- 3.8% (p < 0.003 vs control).

CONCLUSION

The present study shows the high inter- and intra-patient variability of transmembrane passage of albumin in chronically uremic patients undergoing pre-dilutional HDF. Factors involved do not seem to be correlated to transmembrane pressure but rather to an interaction with the polymer surface. Albumin adsorption was minimal and was significantly lower than that of other plasma proteins. Albumin loss during HDF seemed to have no acute impact on plasma albumin. In addition, we demonstrated the presence of prooxidative compounds able to oxidize albumin, of which extracorporeal removal by HDF procedure could be beneficial for HD patients.

Alterations of the cytokine network in hemodialysis

This study focuses on the mechanisms responsible for monocyte activation and enhanced cytokine production in hemodialysis. Particular emphasis is given to recent recognition of a link between cytokine production and chronic inflammation following long-term complications in today's hemodialysis population, namely cardiovascular disease and malnutrition.

[Indicators and evaluation tools for perinatal care networks]

Since the regionalization of perinatal services and the laws on the safety of child-birth were announced on the 9th October 1998, conventions and rules establishing relationships between doctors in perinatal networks have gradually been set up. In order to assess the impact, functioning and effectiveness of this care organisation on the health of mothers an childs, a common study design is essential. Such a common protocol, with the same methodology, allows the comparison of observed results from one perinatal network to another. With this objective, four leading societies in the field, the French National College of Gynaecologists and Obstetricians (CNGOF), the National Federation of Neonatal Pediatricians (FNPN), the French Society of Perinatal Medicine (SFPM) and the Association of Computerised Medical Records in Perinatalogy, Obstetrics and Gynaecology (AUDIPOG) set up a workshop in order to elaborate a common text, which was adopted by the Administrative Councils of the four societies. This contractual text, co-operatively elaborated, is now introduced to the scientific community. It was prepared from scientific papers and international recommendations in the field of perinatal regionalization, leading to a protocol giving information on objectives, study population, study design and assessment criteria. For this, a list of questions was proposed, including the impact of perinatal network, its acceptability by doctors and families, its functioning and its effectiveness on the health of mother and child. The means of data collection were then presented, whether from institutional sources of perinatal data (completed from specific registers or studies), or from the information system France-Perinat, especially designed for the evaluation of the perinatal networks.

Estimation of an expected caesarean section rate taking into account the case mix of a maternity hospital. Analysis from the AUDIPOG Sentinelle Network (France). Obstetricians of AUDIPOG. Association of Users of Computerised Files in Perinatalogy, Obstetrics and Gynaecology

OBJECTIVE

To provide maternity unit with an expected caesarean section rate, according to its case mix (i.e. women's characteristics associated with caesarean section risk).

DESIGN

Cohort study.

SETTING

149 maternity units in France.

SAMPLE

40,512 single births collected by the French Sentinelle Network, in January every year, from 1994 until 1998.

METHODS

Univariate analysis was used to identify caesarean section risk factors, and multivariate analysis to adjust for the role of the maternity units' characteristics, after taking into account the women's characteristics. A two-level logistic model was used to show that the caesarean section rate varied according to maternity units' characteristics and to estimate therefore expected caesarean section rates (before and during labour), for each maternity unit, according to its case mix.

MAIN OUTCOME

Caesarean section rates (before and during labour).

RESULTS

Within the Sentinelle Network the caesarean section rate was 15.0% (7.6% were before labour). The joint effect of the size and juridical status on caesarean section risk was studied. The reference hospital was university maternity units with more than 2000 deliveries/year. Community or private maternity units with more than 2000 deliveries/year carried out fewer prophylactic caesarean sections than the reference hospital (ORadj = 0.7 and 0.6, respectively). Conversely, private maternity units with fewer than 2000 deliveries/year performed more prophylactic caesarean sections than the reference hospital (ORadj = 1.7). The two-level logistic model showed that a maternity unit effect still existed after taking into consideration both women's characteristics and those of the maternity unit, and estimated expected caesarean section rates.

CONCLUSION

Knowledge of the expected caesarean section rate constitutes a personal reference to which the maternity hospital can compare its observed caesarean section rate, and is thus likely to have a significant effect on delivery practices.

A double-blind, randomized comparison of the efficacy and safety of intramuscular injections of olanzapine, lorazepam, or placebo in treating acutely agitated patients diagnosed with bipolar mania

There are no rapid-acting intramuscular formulations of atypical antipsychotics available for quickly calming an agitated patient with bipolar disorder. In this study, 201 agitated patients with bipolar mania were randomly assigned to receive one to three injections of the atypical antipsychotic olanzapine (10 mg, first two injections; 5 mg, third injection), the benzodiazepine lorazepam (2 mg, first two injections; 1 mg, third injection), or placebo (placebo, first two injections; olanzapine, 10 mg, third injection) within a 24-hour period. Agitation was measured at baseline, every 30 minutes for the first 2 hours, and at 24 hours after the first injection using the Positive and Negative Syndrome Scale-Excited Component subscale and two additional agitation scales. At 2 hours after the first injection, patients treated with olanzapine showed a significantly greater reduction in scores on all agitation scales compared with patients treated with either placebo or lorazepam. At 24 hours after the first injection, olanzapine remained statistically superior to placebo in reducing agitation in patients with acute mania, whereas patients treated with lorazepam were not significantly different from those treated with placebo or olanzapine. Furthermore, no significant differences among the three treatment groups were observed in safety measures, including treatment-emergent extrapyramidal symptoms, the incidence of acute dystonia, or QTc interval changes. These findings suggest that intramuscular olanzapine is a safe and effective treatment for reducing acute agitation in patients with bipolar mania.

A time-to-treatment analysis in the medicine versus angiography in thrombolytic exclusion (MATE) trial

Patients with acute coronary syndromes who are considered ineligible for thrombolytic therapy are at high risk of recurrent ischemia and death. This trial randomized 201 patients to triage angiography in the first 24 hours of hospital admission versus conventional medical care. Of the 165 patients who underwent angiography that was either protocol-driven or on the basis of physician preference, those who underwent angiography within 6 hours of symptom onset had a reduction in early and late adverse events. The rates of in-hospital recurrent ischemia were 15.4%, 15.4%, 17.5%, 32.4%, and 38.5%, respectively (P = 0.01 for trend), and rates of cumulative recurrent myocardial infarction or death were 0%, 12.8%, 10.0%, 11.8%, and 7.7%, respectively (P = 0.48 for trend) for patients who underwent angiography at 0-6, 6-12, 12-24, 24-48, and over 48 hours, respectively from symptom onset. Future trials of invasive versus conservative therapy should focus on performing angiography within 6 hours of symptom onset.

Activity against Mycobacterium tuberculosis with concomitant induction of cellular immune responses by a tetraaza-macrocycle with acetate pendant arms

The novel tetraaza-macrocyclic compound 3,7,11-tris(carboxymethyl)-3,7,11,17-tetraaza-bicyclo[11.3.1]heptadeca-1(17),13,15-triene, abbreviated as ac3py14, was investigated for its activity against Mycobacterium tuberculosis and for induction of protective cellular immune responses. Perspective results show that ac3py14 and its Fe3+ 1:1 complex, [Fe(ac3py14)], inhibited radiometric growth of several strains of M. tuberculosis. Inhibition with 25 microg/mL varied from 99% for H37Rv to 80% and above for multiple drug-resistant clinical isolates. The capacity of ac3py14 to elicit a beneficial immune response without cellular apoptosis was assessed and compared to the effects of virulent M. tuberculosis. The present study produces evidence that after stimulation with ac3py14 there was significant production of interferon gamma (IFN-gamma), whereas the production of interleukin-5 (IL-5) remained low, and there was development of a memory population (CD45RO). The level of binding of Annexin V, a marker of apoptosis, was not sufficient to result in toxic effects toward alphabeta and gammadelta T cells and CD14+ macrophages. This preliminary study is the first report of a compound that simultaneously exerts an inhibitory effect against M. tuberculosis and induces factors associated with protective immune responses.

MIP-1alpha, MCP-1, GM-CSF, and TNF-alpha control the immune cell response that mediates rapid phagocytosis of myelin from the adult mouse spinal cord

The slow immune response in the adult mammalian CNS results in slow myelin phagocytosis along degenerating white matter after injury. This has important consequences for axon regeneration because of the presence of axon growth inhibitors in myelin. In addition, abnormal immune cell responses in the CNS lead to demyelinating disease. Lysophosphatidylcholine (LPC) can induce an inflammatory response in the CNS, producing rapid demyelination without much damage to adjacent cells. In this study, we searched for the molecular switches that turn on this immune cell response. Using reverse transcription PCR analysis, we show that mRNA expression of macrophage inflammatory protein-1alpha (MIP-1alpha), macrophage chemotactic protein-1 (MCP-1), granulocyte macrophage-colony stimulating factor (GM-CSF), and tumor necrosis factor-alpha (TNF-alpha) in the spinal cord is rapidly and transiently upregulated after intraspinal injection of LPC. Neutralizing these signaling molecules with function-blocking antibodies suppresses recruitment of T-cells, neutrophils, and monocytes into the spinal cord, as well as significantly reduces the number of phagocytic macrophages and the demyelination induced by LPC. These findings will have important implications for CNS regeneration and demyelinating disease.

The anomalous reactivity of the bis(dibutylstannylene) acetal of pentaerythritol: a case of triple activation

The only dibutyltin derivative of pentaerythritol which is observed by refluxing with dibutyltin oxide in methanol is a bis(dibutylstannylene) acetal. This is converted to the expected dibenzyl ether with benzyl bromide, in the presence of tetraethylammonium bromide in boiling toluene, but benzoylation at room temperature gives a tribenzoate. A mechanism is suggested to account for this triple activation.

Synergic activity of D-cycloserine and beta-chloro-D-alanine against Mycobacterium tuberculosis

D-Cycloserine (DCS) is a peptidoglycan inhibitor. Although very effective against Mycobacterium tuberculosis, it is seldom employed in the management of this infection due to its high toxicity. beta-Chloro-D-alanine (another peptidoglycan inhibitor) reduces the MIC of DCS from 50 to 2.5 mg/L at a concentration significantly below its MIC for this organism. A reduction in bacterial viability and significant growth inhibition (as quantified by the X/Y quotient for the Bactec radiometric procedure) were observed with subinhibitory concentrations of both drugs. It is suggested that this powerful synergic effect should be the object of in vivo and eventually clinical trials.

Opioid antagonists for smoking cessation

BACKGROUND

The reinforcing properties of nicotine may be mediated through release of various neurotransmitters both centrally and systemically. Smokers report positive effects such as pleasure, arousal, and relaxation as well as relief of negative affect, tension, and anxiety. Opioid (narcotic) antagonists are of particular interest to investigators as potential agents to attenuate the rewarding effects of cigarette smoking.

OBJECTIVES

To evaluate the efficacy of opioid antagonists in promoting long-term smoking cessation. The drugs include naloxone and the longer-acting opioid antagonist naltrexone.

SEARCH STRATEGY

We searched the Cochrane Tobacco Addiction Group trials register for trials of naloxone, naltrexone and other opioid antagonists and conducted an additional search of Medline using '"Narcotic antagonists" and smoking terms in March 2001. We also contacted, when possible, investigators for information on unpublished studies.

SELECTION CRITERIA

We considered randomized controlled trials comparing opioid antagonists to placebo or an alternative therapeutic control for smoking cessation. We included only trials reporting data on abstinence of a minimum of 6 months in the meta-analyses. We also reviewed, for descriptive purposes, results from short-term laboratory-based studies of opioid antagonists designed to evaluate psychobiological mediating variables associated with nicotine dependence.

DATA COLLECTION AND ANALYSIS

We extracted data in duplicate on the type of study population, the nature of the drug therapy, the outcome measures, method of randomisation, and completeness of follow-up. The main outcome measure was cotinine or carbon monoxide verified abstinence from smoking after at least six months follow-up in patients smoking at baseline. Where appropriate, we performed meta-analysis using a fixed effects model (Peto method).

MAIN RESULTS

Two trials of naltrexone met inclusion criteria for meta-analyses for long term cessation. Both trials failed to detect a significant difference in quit rates between naltrexone and placebo. In a pooled analysis there was no significant effect of naltrexone on long-term abstinence, and confidence intervals were wide (OR 1.34, 95% CI 0.49,3.63). No trials of naloxone or buprenorphine reported long term follow-up

REVIEWER'S CONCLUSIONS

Based on limited data from two trials it is not possible to confirm or refute whether naltrexone helps smokers quit. The confidence intervals are compatible with both clinically significant benefit and possible negative effects of naltrexone in promoting abstinence. Data from larger trials of naltrexone are needed to settle the question of efficacy for smoking cessation.

Protection and humoral immune responses against Bordetella pertussis infection in mice immunized with acellular or cellular pertussis immunogens

In the present study, protection against Bordetella pertussis infection and humoral immunological responses in mice has been assessed upon immunization with custom-made acellular pertussis vaccines (ACVs) and whole-cell pertussis vaccine (WCV). Mice were immunized, next intranasally infected with B. pertussis and during 14 days the number of bacteria in the trachea and lungs and the level of serum antibodies were determined. ACV contained five immunogens, filamentous hemagglutinin, pertactin, fimbriae serotypes 2 and 3, and chemically detoxified pertussis toxin (PMC-5), or three immunogens, filamentous hemagglutinin, pertactin, and genetically detoxified (BC-3) or chemically detoxified pertussis toxin (SKB-3). Immunization with a high or low dose of ACV or WCV resulted in significant protection against B. pertussis, with differences in the degree of protection between the vaccines. The lowest protection was found with a low dose of SKB-3 and WCV. The pattern of cytokine production by spleen cells of immunized, non-infected, mice indicated that T-helper 1 cells are activated by vaccination with WCV, and T-helper 1 and T-helper 2 cells are involved in the immune response upon vaccination with ACVs. Each vaccine stimulated the production of IgG, but not IgA, antibodies. In mice immunized with ACV, elimination of B. pertussis from trachea and lungs correlated significantly with the titre of IgG1, but not IgG2a, antibodies.

[Who delivers where? Who is born where? Analysis of the 1997-1998 AUDIPOG Sentinel Network]

OBJECTIVE

The purpose of this study was to describe the care level, legal status and size of the maternity units where deliveries take place in France according to risk level for mother and infant. We analyzed the 1997-1998 data to better implement the network's perinatal policy.

MATERIAL

and methods. Our standardized sample included 4200 single births in 1997 and 3650 in 1998 collected by the French Sentinel Network after applying a sample rectification technique to offset the methodological problems created by the volunteer nature of the sample population. Distribution of care level, legal status and size of the maternity unit where deliveries took place were recorded according to the risk level of the patients.

RESULTS

In 1997-1998, 22% of pregnant women delivered in level III maternity units and 33% in level II units. Twenty percent of the deliveries took place in level II maternity units with less than 1500 deliveries per year. During this period, women with diabetes or hypertension delivered more often in level III units (31% and 27% respectively) than women in the general population. This was not true for women with a previous perinatal death (23%). Inversely, births of infants before 33 weeks gestation or weighing less than 1500 g occurred more often in level III maternity units (55% and 59% respectively) than in the general population. Twenty-seven percent of the infants requiring neonatal transportation were born in level I maternity units. For 'low risk' mothers, delivery occurred more often in level I maternity units (more than 50%) or in small maternity units with less than 1000 deliveries per year (45%) than for the general population (45% and 36% respectively).

CONCLUSION

These data obtained from the Sentinel Network provide precise information on where deliveries occur in France. These data will be useful for implementing the network's perinatal policy. They will also provide a means of following referral practices in the future.

Profile of hospital admissions following acute poisoning--experiences from a major teaching hospital in south India

This study was conducted to determine the incidence of hospital admissions following acute poisoning, nature of agents involved and change in pattern of poisoning over a 5-year period. Data from hospital records of all admissions to emergency department following acute poisoning collected prospectively were analysed for the period January 1993 to January 1998. A steady increase in deliberate poisoning using pesticides, particularly among young adults, was noted. Kerosene (paraffin) was the commonest poison in children and plant poisons were also common. There were 52 deaths (3.3%) among the 1584 admissions. The majority of deaths were due to pesticides. Poisoning and mortality followed ingestion of readily-available and commonly used agents. Measures to increase public education, counselling and awareness could prevent a number of these admissions.

Impaired culprit vessel flow in acute coronary syndromes ineligible for thrombolysis

The majority of patients with acute myocardial infarction and other acute coronary syndromes (ACS) are considered ineligible for thrombolysis and do not routinely receive reperfusion therapy. We hypothesized that predictors and outcomes of angiographically impaired culprit vessel flow can be identified and compared. This trial evaluated the outcomes following triage angiography in acute coronary syndromes ineligible for thrombolytic therapy. Eligible patients (n=201) with<24 hours of symptoms were randomized to early triage angiography and subsequent therapies based on the angiogram versus conventional medical therapy. This analysis was performed in 165 patients, from experimental and control arms, in whom angiography was performed on the index hospitalization with the outcome of interest being target vessel flow (Thrombolysis In Myocardial Infarction [TIMI] grades 0 to 2) on initial angiography. Patients with and without impaired culprit lesion flow were similar with respect to age, gender, diabetes, and prior coronary disease. A family history of premature coronary disease was more common in those with impaired flow, 50.0 versus 28.5% (p=0.02). Abnormal culprit vessel flow was found in 19.2% of patients who underwent angiography within 6 hours of symptom onset; however, after 24 hours this rate was reduced to 11.7%. Impaired culprit lesion flow can be expected in approximately 20% of patients presenting with ACS who are ineligible for reperfusion therapy by conventional guidelines and therefore represents an opportunity for early intervention within 6 hours of the onset of symptoms in these patients.

In vitro susceptibilities of Capnocytophaga isolates to beta-lactam antibiotics and beta-lactamase inhibitors

The susceptibilities of 43 pharyngeal isolates of Capnocytophaga to beta-lactam antibiotics, alone or in combination with beta-lactamase inhibitors, were tested by an agar dilution method. The 34 beta-lactamase-positive strains were highly resistant to beta-lactams, but the intrinsic activities of clavulanate, tazobactam, and sulbactam against Capnocytophaga, even beta-lactamase producers, indicates that these beta-lactamase inhibitors could be used for empirical treatment of neutropenic patients with oral sources of infection.

The intermolecular migration of polyol stannylenes as a reaction contributing to the regioselectivity of substitution

Pairs of the partially protected glycosides benzyl 4,6-O-benzylidene-beta-D-galactopyranoside, benzyl 2,3-di-O-benzyl-beta-D-galactopyranoside, benzyl 2,6-di-O-benzyl-alpha-D-galactopyranoside, and benzyl 2,3-di-O-benzyl-alpha-D-glucopyranoside were treated with equimolar proportions of Bu2SnO in benzene in the conditions of stannylene formation, and the resulting mixture was benzoylated in situ with benzoyl chloride. Estimation of the product of benzoylation led to the following order of reactivity in the stannylenation reaction: 2,3-diol > 4,6-diol, and 2,3-diol > 3,4-diol. An intermolecular migration of dibutyltin between sugars was demonstrated. It is considered that these migrations contribute efficiently to the regiospecificity of the stannylene reaction.

Wide angularly isotropic photonic bandgaps obtained from two-dimensional photonic crystals with Archimedean-like tilings

We present a theoretical study of new two-dimensional photonic crystals based on Archimedean-like tilings. Three structures are considered: a square lattice with a 4-atom unit cell and triangular lattices with 7- and 13-atom unit cells. A 12-fold local rotational symmetry is obtained for the triangular lattices and is approached for the square lattice. Wide photonic bandgaps can then be achieved, with very weak bandwidth dependence (~1%) on the wave-propagation direction. The complete bandgap frequency is shown to depend on the atomic bond length and not on the crystal period. This new class of periodic photonic crystals is a simple and attractive alternative to photonic quasi crystals.

Ocular cysticercosis--a review of 25 cases

OBJECTIVE

To study the clinical manifestations, management and outcome of cases of ocular cysticercosis in India.

METHODS

Retrospective analysis of records of patients presenting to the ophthalmology clinics, with cysticercosis, during years 1990-98.

RESULTS

A total of 25 patients had ocular cysticercosis, during the period studied. Majority could be surgically removed without residual effects. However four patients (16%) had no useful vision left in the involved eye.

CONCLUSION

Cysticercosis is still endemic in India and contributes to preventable blindness. Improving sanitation and health awareness are the only ways to prevent this infection.