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The survival benefit of measles immunization may not be explained entirely by the prevention of measles disease: a community study from rural Bangladesh.

OBJECTIVE: To examine whether the reduction in childhood mortality after immunization can be explained by the prevention of measles and its long-term effects. METHODS: and Data We re-analysed an existing data set from Matlab, Bangladesh. During 1982-1985, measles immunization was used from 9 months of age in half of the study area, and the other half was used as an unvaccinated control area. A total of 8134 immunized children had been matched by age with 8134 non-immunized children; 578 children died during the follow-up period of 3 years. Using these data, we calculated the vaccine effectiveness against death (VED) controlling for significant factors in a matched analysis. In the absence of measles, there should be no difference in mortality between immunized, uninfected children and non-immunized, uninfected children. We therefore calculated VED after the exclusion of all measles cases in the survival analysis. To assess the long-term effects of measles, we compared survival of unvaccinated children after measles disease with children who had not yet contracted measles. RESULTS: Prior to immunization and again after 1985, childhood mortality rates were 10% lower in the area that had received immunization. Though measles deaths only constituted 12.4% of the non-accidental deaths, the VED controlling for significant factors was 49% (95% CI: 38-58%). The vaccine was protective against measles death throughout the study, but it also had a marked effect against other causes of death, particularly diarrhoea and oedema. This effect may have been particularly strong in the first 6 months after immunization (VED = 74, 95% CI: 57-84%). The VED was only reduced from 49% to 43% (95% CI: 31-54%) when measles cases were excluded in the survival analysis. Controlling for background factors, mortality among measles cases was increased during the acute phase (0-45 days) (mortality ratio [MR] = 17.35, 95% CI: 11.9-25.3) and in the following 1(1/2) months (MR = 2.35, 95% CI: 0.95-5.84). However, post-measles cases had significantly lower mortality than uninfected, non-immunized children in the following 9 months (MR = 0.40, 95% CI: 0.16, 0.98). CONCLUSIONS: The non-randomized character of the original study and the possibility of uncontrolled confounding between the two areas prevent a precise estimate of the effectiveness of measles vaccine, but it is likely to have been substantial. Though there may have been some underreporting of cases of measles, the prevention of measles infection can only explain a limited part of the observed impact of measles immunization in Bangladesh. Furthermore, mortality may be reduced after the acute phase of measles infection. The observations from Bangladesh are consistent with recent research from Africa suggesting that measles immunization may have non-specific beneficial effects on survival.

Bangladesh↗

Mutagen sensitivity: a biological marker of cancer susceptibility.

We intend to continue our exploration of the bleomycin assay as a biological marker for the development of environmentally induced cancers. The impetus for such efforts would be enhanced through effective integration of cancer screening and intervention to achieve diminished cancer mortality. Currently, we are integrating combining bleomycin sensitivity screening to chemopreventive therapy against second primary malignancies in head and neck cancer patients. Previous studies have demonstrated that cis-retinoic acid, the agent used in our chemopreventive trial, is effective in such circumstances (35). Our purpose is to identify a high-risk subpopulation through application of the bleomycin sensitivity assay and then demonstrate that we can modulate the carcinogenic process with cis-retinoic acid. The use of genetic markers clearly enhances the power and precision of epidemiological research. The preventive implications of precise and valid markers for carcinogen sensitivity are obvious. We are aware of the need for extensive validation of the assay and for rigorously designed and conducted epidemiological studies. The strength of the association between cancer risk and mutagen sensitivity, despite the inherent problems in the size and design of the studies, is noteworthy. The thesis that chromosome instability and defective DNA repair may underlie susceptibility to environmental carcinogenesis is plausible and presents a promising avenue for further multidisciplinary research.

Alcohol Drinking↗

[Postero-internal menisco-capsular disinsertions associated with chronic instabilities of the knee caused by rupture of the anterior cruciate ligament].

Posterior menisco-capsular tears of the medial compartment of the knee can be considered as a complication of rupture of the anterior cruciate ligament and the consequent medial instability. The lesion is more a capsular lesion than a true meniscal one and it is related to an excessive stress on the oblique fibres of the ligament of Hughston attached to the meniscus. The diagnosis is based on arthrography made with meticulous technique. The lesion must be differentiated from true meniscal tears because it can be sutured. One hundred and twenty five such lesions have been operated on and reviewed after a follow-up of an average of two years. The technique must be very precise to prevent any secondary lesion due to surgery and to avoid any plaster cast immobilisation. The results have been satisfactory in 69 p. 100. They should be improved with more accurate surgical technique and with more precise indications.

Arthroscopy↗

Alcaligenes xylosoxidans dissimilatory nitrite reductase: alanine substitution of the surface-exposed histidine 139l ligand of the type 1 copper center prevents electron transfer to the catalytic center.

Nitrite reductase of Alcaligenes xylosoxidans contains three blue type 1 copper centers with a function in electron transfer and three catalytic type 2 copper centers. The mutation H139A, in which the solvent-exposed histidine ligand of the type 1 copper ion was changed to alanine, resulted in the formation of a colorless protein containing 4.4 Cu atoms per trimer. The enzyme was inactive with reduced azurin as the electron donor, and in contrast to the wild-type enzyme, no EPR features assignable to type 1 copper centers were observed. Instead, the EPR spectrum of the H139A enzyme, with parameters of g(1) = 2.347 and A(1) = 10 mT, was typical of type 2 copper centers. On the addition of nitrite, the EPR features developed spectral features with increased rhombicity, with g(1) = 2.29 and A(1) = 11 mT, arising from the type 2 catalytic site. As assessed by visible spectroscopy, ferricyanide (E degree = +430 mV) was unable to oxidize the H139A enzyme, and this required a 30-fold excess of K(2)IrCl(6) (E degree = +867 mV). Oxidation resulted in the EPR spectrum developing additional axial features with g(1) = 2.20 and A(1) = 9.5 mT, typical of type 1 copper centers. The oxidized enzyme after separation from the excess of K(2)IrCl(6) by gel filtration was a blue-green color with absorbance maxima at 618 and 420 nm. The instability of the protein prevented the precise determination of the midpoint potential, but these properties indicate that it is in the range 700-800 mV, an increase of at least approximately 470 mV compared with the native enzyme. This high potential, which is consistent with a trigonal planar geometry of the Cu ion, effectively prevents azurin-mediated electron transfer from the type 1 center to the catalytic type 2 Cu site. However, with dithionite as reductant, 20% of the activity of the wild-type enzyme was observed, indicating that the direct reduction of the catalytic site by dithionite can occur. When CuSO(4) was added to the crude extract before isolation of the enzyme, the Cu content of the purified H139A enzyme increased to 5.7 Cu atoms per trimer. The enzyme remained colorless, and the activity with dithionite as a donor was not significantly increased. The additional copper in such preparations was associated with an axial type 2 Cu EPR signal with g(1) = 2.226 and A(1) = 18 mT, and which were not changed by the addition of nitrite, consistent with the activity data.

Alanine↗

[Prevention of AIDS transmission by syringes and needles in France and Africa].

A study made among drug addicts in the Northern suburbs of Paris enables establishing a stabilisation of positive H.I.V. serology prevalence among them, a fact related to the free sale of syringes and needles. In Africa, the nosocomial transmission of H.I.V. by non-sterilisable but reused needles and syringes is demonstrated, and two cases are described. Its importance is certain but must be precise. The prevention of this epidemiological modality must be done by systematic use of reusable and sterilisable injectable material.

Acquired Immunodeficiency Syndrome↗

Eye metastasis from carcinoma of the breast: diagnosis, radiation treatment and results.

The experience at the Gershenson Radiation Oncology Center of 32 cases of metastases to the eye or orbit from breast cancer are presented with a review of the literature. The 32 patients were referred for radiation therapy in the period of 1980-1991. Eighteen patients had metastasis to the choroid, 2 patients had involvement of other parts of the eye (anterior chamber +/- choroid), and 11 patients had orbital metastasis. In one patient, the diffuse nature of the disease prevents subsite assignment. Ten of the patients with eye metastases also had brain or meningeal metastases (8 patients concurrent with eye metastases). Four of the 32 patients had bilateral choroidal metastases. A complete course of radiation therapy was delivered to 28 patients, one patient was not treated and 3 patients received only partial treatment because of general deterioration due to other widespread metastases from breast cancer. Of 21 evaluable patients, 15 had definite improvement. There was no progression of the eye metastases in the other 6 patients. The rest (7 patients) were lost to detailed follow-up of the response of the eye metastases. Four patients are still alive without any severe long-term side-effects. The diagnosis, treatment and outcome is presented with a review of the literature. The importance of emergency treatment for rapidly progressing lesions is stressed as well as the need for detailed treatment planning, careful delivery of daily treatments with a high degree of reproducibility and precision to prevent possible damage to sensitive normal structures.

Adult↗

Regionalized transcriptional domains of myosin light chain 3f transgenes in the embryonic mouse heart: morphogenetic implications.

Within the embryonic heart, five segments can be distinguished: two fast-conducting atrial and ventricular compartments flanked by slow-conducting segments, the inflow tract, the atrioventricular canal, and the outflow tract. These compartments assume morphological identity as a result of looping of the linear heart tube. Subsequently, the formation of interatrial, interventricular, and outflow tract septa generates a four-chambered heart. The lack of markers that distinguish right and left compartments within the heart has prevented a precise understanding of these processes. Transgenic mice carrying an nlacZ reporter gene under transcriptional control of regulatory sequences from the MLC1F/3F gene provide specific markers to investigate such regionalization. Our results show that transgene expression is restricted to distinct regions of the myocardium: beta-galactosidase activity in 3F-nlacZ-2E mice is confined predominantly to the embryonic right atrium, atrioventricular canal, and left ventricle, whereas, in 3F-nlacZ-9 mice, the transgene is expressed in both atrial and ventricular segments (right/left) and in the atrioventricular canal, but not in the inflow and outflow tracts. These lines of mice illustrate that distinct embryonic cardiac regions have different transcriptional specificities and provide early markers of myocardial subdivisions. Regional differences in transgene expression are not detected in the linear heart tube but become apparent as the heart begins to loop. Subsequent regionalization of transgene expression provides new insights into later morphogenetic events, including the development of the atrioventricular canal and the fate of the outflow tract.

Animals↗

Construction of an intron-containing marker gene: splicing of the intron in transgenic plants and its use in monitoring early events in Agrobacterium-mediated plant transformation.

Agrobacterium tumefaciens is a commonly used tool for transforming dicotyledonous plants. The underlying mechanism of transformation however is not very well understood. One problem complicating the analysis of this mechanism is the fact that most indicator genes are already active in Agrobacterium, thereby preventing the precise determination of timing and localisation of T-DNA transfer to plant cells. In order to overcome this obstacle a modified prokaryotic indicator gene was constructed. The expression of this indicator gene and its use in analysing early events in Agrobacterium-mediated plant transformation are described. A portable intron, derived from a plant intron, was introduced into the beta-glucuronidase (GUS) gene. In transgenic plants containing this chimaeric gene the intron is spliced efficiently, giving rise to GUS enzymatic activity. Mapping of the splice junction indicates the exact removal of the intron. No GUS activity is detected in agrobacteria containing this construct due to the lack of a eukaryotic splicing apparatus in prokaryotes. Early phases after transformation of Arabidopsis cotyledon explants were analysed using this GUS-intron chimaeric gene showing that as early as 36 h after Agrobacterium infection significant GUS activity is detected. In vivo GUS staining of transformed cells clearly shows that quickly proliferating calli expressing GUS activity are formed, mainly at the cut surface. Minor transformation events occur however throughout the whole cotyledon. These data indicate that Agrobacterium-mediated T-DNA transfer to plants is much more efficient than has been judged from experiments where selection is applied immediately. The intron-containing GUS gene can be used as an optimised marker gene in transient and stable transformation experiments.

Base Sequence↗

Collaboration of breast cancer clinic and genetic counseling division for BRCA1 and BRCA2 mutation family in Japan.

BACKGROUND: BRCA1 and BRCA2 mutations cause high breast cancer incidence rates as high as 80% Although prophylactic therapy is still controversial, several prophylactic therapies have been proposed and tried for BRCA1 and BRCA2 mutation carriers. Prophylactic surgery, chemo-prevention and precise screening have been proposed as prophylactic therapy. All BRCA1 and BRCA2 mutation carriers need knowledge about their disease and the countermeasures that are used to protect against onset of disease. Counseling plays an important role in this regard for people with genetic diseases. Therefore, collaboration between breast cancer clinics and genetic counseling services is the most important issue in clinical practice. Our group consists of three national universities and a general hospital. In this article we describe our trial to construct a clinical system against hereditary breast cancer as an interim report for the Japanese Ministry of Health, Labour and Welfare. PATIENTS AND METHODS: Twenty familial breast cancer patients were registered in this study. The whole sequence of BRCA1 and BRCA2 were analyzed. If pathological mutations were detected, their first degree families were introduced to the counseling division at each institute when candidates visited counseling divisions. RESULTS AND DISCUSSION: Four cases of a deleterious mutation in BRCA1 or BRCA2 were detected among 20 cases. Their first degree relatives are now under consideration for visiting counseling divisions. The clinical system described in this study should play a role to protect BRCA1 or BRCA2 mutation carriers in Japan.

Breast Neoplasms↗

[Office workplace at a computer monitor from an occupational-orthopedic view].

Typical back problems as well as complaints in the shoulder-arm-hand system are increasing as the volume of sedentary office work at the computer screen rises. Various legal rules precisely define preventive measures. However, basic orthopedic-biomechanical principles are not being taken into consideration. Orthopedists as well as occupational physicians are equally challenged to enforce those legal guidelines by beginning to raise awareness of the principles and thus contributing towards improvement of working conditions.

Computer Terminals↗

Determination of pseudouridine and other nucleosides in human blood serum by high-performance liquid chromatography.

A specific, sensitive, and rapid method to measure pseudouridine in human blood serum is described. The method is based on the following steps: (i) deproteinization of serum samples by filtration on membrane cones or by acetonitrile; (ii) purification of nucleosides and concentration of the sample by affinity chromatography on phenylboronate gel followed by lyophilization; and (iii) separation of nucleosides and their quantitation by reverse-phase high-performance liquid chromatography. The pseudouridine mean value in 30 normal subjects was 2.52 +/- 0.28 nmol/ml. The procedure also allows the identification of inosine, uridine, guanosine, and adenosine. Nevertheless, the presence in human blood serum of enzymatic activities which convert adenosine to inosine and cytidine to uridine prevents the precise quantitation of these nucleosides. All the compounds were identified by comparing their retention times and absorbance ratios (A280/A254) with those of pure compounds, as well as by cochromatography.

Chromatography, High Pressure Liquid↗

Punch shear testing of extracted vital and endodontically treated teeth.

Plano-parallel specimens of human dentin cut from vital and endodontically treated teeth were tested by the punch shear test. Shear strength values were found to positively correlate with approximate toughness values. Statistically significant differences were found between shear strength and toughness values for vital and endodontically treated teeth, the latter showing lower values. The clinical impression that endodontically treated teeth are weaker and more brittle than vital teeth has therefore been quantitated. Anatomically different teeth or the methods used to store and cut teeth could not be consistently correlated with punch shear and toughness values. When dentin slices were constrained during punching so that bending was prevented, the precision of the results was improved and higher values were recorded.

Adult↗

[Heller's myotomy without fundoplication: a series of 123 patients].

INTRODUCTION: Surgical treatment of achalasia of lower oesophageal sphincter is Heller's myotomy, usually associated with a fundoplication due to an high risk of postoperative gastro-oesophageal reflux. The value of this fundoplication is discussed. The aim of this study was to evaluate retrospectively the results of Heller's myotomy without fundoplication but performed according to a precise technique preventing postoperative reflux. PATIENTS AND METHODS: Between 1975 and 1999, 123 patients underwent Heller's myotomy without systematic fundoplication. Diagnosis of achalasia was performed clinically and confirmed by investigations: baryum meal, fibroscopy and manometry. Myotomy was performed through an abdominal approach in 117 (95%) patients. Dissection preserved fixity of abdominal oesophagus in all cases, particularly its posterior meso. Myotomy was performed on abdominal oesophagus but not below the cardia. Posterior fundoplication was associated in 2 patients. RESULTS: One patient (0,8%) died from massive aspiration. Morbidity (1,6%) consisted in one peritonitis and one postoperative occlusion. At follow-up (mean = 5 years; range: 1-20), functional results were satisfying (excellent and good) in 112 (92%) patients. Seven patients (6%) developed postoperative reflux, including one who need surgical treatment. Dysphagia persisted in 3 patients (2%) who had to be reoperated. CONCLUSION: Results of this series show that systematic fundoplication is not necessary in Heller's myotomy for achalasia of lower oesophageal sphincter.

Adolescent↗

Localization of genes affecting species differences in male courtship song between Drosophila virilis and D. littoralis.

The males of six species of the Drosophila virilis group (including D. virilis) keep their wings extended while producing a train of sound pulses, where the pulses follow each other without any pause. The males of the remaining five species of the group produce only one sound pulse during each wing extension/vibration, which results in species-specific songs with long pauses (in D. littoralis about 300 ms) between successive sound pulses. Genetic analyses of the differences between the songs of D. virilis and D. littoralis showed that species-specific song traits are affected by genes on the X chromosome, and for the length of pause, also by genes on chromosomes 3 and 4. The X chromosomal genes having a major impact on pulse and pause length were tightly linked with white, apricot and notched marker genes located at the proximal third of the chromosome. A large inversion in D. littoralis, marked by notched, prevents more precise localization of these genes by classical crossing methods.

Animals↗

Comparison of isotope dilution mass spectrometry methods for the determination of total homocysteine in plasma and serum.

Two independent methods have been critically evaluated and applied to the measurement of total homocysteine in serum and plasma: solid-phase anion extraction (SPAE) gas chromatography/mass spectrometry (GC/MS) and protein precipitation liquid chromatography/tandem mass spectrometry (LC/MS/MS). In addition, analysis of samples prepared by SPAE was accomplished by liquid chromatography/mass spectrometry (LC/MS) and LC/MS/MS. These methods have been used to determine total homocysteine levels in several existing serum-based Standard Reference Materials (SRMs) from the National Institute of Standards and Technology and in patient plasma samples provided by the Centers for Disease Control and Prevention. The precision of the homocysteine measurements in serum and plasma was critically evaluated, and method comparisons were carried out using Bland-Altman plots and bias analysis. On the basis of the excellent precision and close agreement of the mass spectrometric (MS) methods, the MS-based methods will be used for certification of a serum-based SRM for homocysteine and folates.

Chromatography, Liquid↗

Effects of paramagnetic ferrocenium cations on the magnetic properties of the anionic single-molecule magnet [Mn(12)O(12)(O(2)CC(6)F(5))(16)(H(2)O)(4)]-.

The preparation and physical characterization are reported for the single-molecule magnet salts [M(Cp')(2)](n)()[Mn(12)O(12)(O(2)CC(6)F(5))(16)(H(2)O)(4)] (M = Fe, n = 1, Cp' = C(5)Me(5) (2a), C(5)H(5) (2b); M = Co, n = 1, Cp' = C(5)Me(5) (2c), C(5)H(5) (2d); M = Fe, n = 2, Cp' = C(5)Me(5) (2e), C(5)H(5) (2f)) to investigate the effects of paramagnetic cations on the magnetization relaxation behavior of [Mn(12)]- anionic single-molecule magnets. Complex 2a.2H(2)O crystallizes in the orthorhombic space group Aba2, with cell dimensions at 173 K of a = 25.6292(2) A, b = 25.4201(3) A, c = 29.1915(2) A, and Z = 4. Complex 2c.2CH(2)Cl(2).C(6)H(14) crystallizes in the monoclinic space group P2(1)/c, with cell dimensions at 173 K of a = 17.8332(6) A, b = 26.2661(9) A, c = 36.0781(11) A, beta = 92.8907(3) degrees, and Z = 4. These two salts consist of either paramagnetic [Fe(C(5)Me(5))(2)]+ cations or diamagnetic [Co(C(5)Me(5))(2)]+ cations, and [Mn(12)O(12)(O(2)CC(6)F(5))(16)(H(2)O)(4)]- anions. The structures of the anions in the two salts are similar, consisting of a central Mn(4)O(4) cubane moiety, surrounded by a nonplanar ring of eight Mn atoms that are bridged by and connected to the cube via mu(3)-O(2)- ions. The oxidation states of four Mn sites out of eight outer Mn ions in complex 2a were assigned to be +2.75 from the valence bond sum analysis although the disordering of bridging carboxylates prevents more precise determination. On the other hand in complex 2c, one Mn site out of eight outer Mn ions was identified as a Mn(II) ion, accommodating the "extra" electron; this was deduced by a valence bond sum analysis. Thus, the anion in complex 2c has a Mn(II)(1)Mn(III)(7)Mn(IV)(4) oxidation state description. The Jahn-Teller axes of the Mn(III) ions in both anions are roughly aligned in one direction. All complexes studied exhibit a single out-of-phase ac magnetic susceptibility (chi"(M)) signal in the 4.6-4.8 K range for complexes 2a-2d and in the 2.8-2.9 K range for complexes 2e and 2f at 1 kHz ac frequency. The temperature of the chi"(M) peaks is frequency dependent, as expected for single-molecule magnets. From Arrhenius plots of the frequency dependence of the temperature of the chi"(M) maxima, the effective energy barriers U(eff) for changing spin from "up" to spin "down" were estimated to be 50-54 K for complexes 2a-2d and 27-28 K for complexes 2e and 2f. The least-squares fits of the reduced magnetization data indicate that both complexes 2a and 2d have ground states of S = (21)/(2). High-frequency EPR spectra were recorded for complex 2a at frequencies of 217, 327, and 434 GHz in the 4.5-30 K range. The observed transition fields were least-squares fit to give g = 1.91, D = -0.35 cm(-1), and B(4)(0) = -3.6 x 10(-7) cm(-1) for the S = (21)/(2) ground state. The effective energy barrier U(eff) is slightly lower than U estimated from D, which is consistent with the thermally assisted tunneling model. Magnetization hysteresis loops were observed for complexes 2a and 2c. Although 2a was oriented in a different manner as expected by strong magnetic field, both complexes show clear hysteresis loops with some steps on them, indicating that the effect of the magnetic cation on the magnetization relaxation of the anionic [Mn(12)]- complex is rather small. An 11% (57)Fe enriched complex 2b was studied by means of Mössbauer spectroscopy down to as low as 1.7 K. Slow paramagnetic relaxation broadening and magnetic hyperfine splitting were evident in the low-temperature spectra, indicating that the iron atoms feel a growing magnetic field owing to slow magnetization reversal in the [Mn(12)]- anions.

Journal Article↗

Conformational analysis of the type II and type III collagen alpha-1 chain C-telopeptides by 1H NMR and circular dichroism spectroscopy.

The type II and type III collagen alpha-1 chain C-telopeptides are a 27 mer with the sequence NAc-GPGIDMSAFAGLGPREKGPDPLQYMRA and a 22mer,NAc-GGGVASLGAGEKGPVGYGYEYR, respectively. Their conformations have been studied in CD3OH/H2O (80/20) solution by means of two-dimensional proton NMR and CD spectroscopy. Based on TOCSY and NOESY experiments, all resonances were assigned and the conformational properties were analyzed in terms of vicinal NH-H alpha coupling constants, sequential and medium range NOEs and amide proton temperature coefficients. The conformation of the type II C-telopeptide is essentially extended. Evidence from CD spectroscopy suggests that a very minor proportion of the peptide might be helical (ca.8%), but the NMR data show no evidence for a non-linear structure. The observation of reduced amide proton temperature dependence coefficients in certain sections of the molecule can, in view of the absence of any other supporting evidence, only be interpreted in terms of local shielding from solvent for sterical reasons (large hydrophobic side-chains). The conformation of the type III C-telopeptide is mostly extended except for a beta-turn ranging from Gly8 to Glu11, which is stabilized by a hydrogen-bond between NH of Glu11 and the carbonyl group of Gly8. The low temperature coefficient of NH(Glu11) and, in particular, the observation of a medium range NOE between H alpha (A9) and NH(E11) corroborate the existence of a beta-turn in this region. Although spectral overlap prevents a precise conclusion with regard to the type of beta-turn present, there is some evidence that it might be type II.

Amino Acid Sequence↗

The frontline of HIV1 diffusion in the Central African region: a geographical and epidemiological perspective.

The geographical analysis of the main data on the HIV1 epidemic in Central Africa shows a frontline which has not moved significantly since 1985. The absence of a progressive increase between the countries, demonstrating a discontinuity in space, combined with the observed human and physical continuity within the areas, raises several questions. Are the low-rate areas facing only a simple delay in the diffusion, or is there a real difference between the epidemiological patterns of HIV1 in the two areas? The last hypothesis would impose a revision of the concept of an homogeneous pattern in the epidemiology of HIV1 in Africa. The need for further research is emphasized with the aim of precisely targeting preventive intervention.

Acquired Immunodeficiency Syndrome↗