Incremental beamwise backprojection using geometrical symmetries for 3D PET reconstruction in a cylindrical scanner geometry

Cho et al have proposed a fast backprojection scheme for parallel beam geometries, the incremental algorithm, which performs backprojection on a ray-by-ray (beam-by-beam) basis as opposed to a pixel-by-pixel approach. We present an extension of this incremental, beamwise, backprojection algorithm to the case of volume reconstruction of data acquired by a cylindrical, multiring positron tomograph. Use is made of geometrical symmetries of the image volume. This method results in a twelve-fold reduction of execution time compared with a straightforward, voxel-driven implementation of the same interpolation equations.

Reflections on the management of cerebral arteriovenous malformations

BACKGROUND

The authors report their personal experience in the management of cerebral arteriovenous malformations (AVMs), using the three techniques now available: surgical resection, endovascular embolization, and radiosurgery. They review the recent literature on this topic and present their current management algorithm based on this experience.

METHODS

A series of 90 patients treated for cerebral AVMs is reported (68% Grade I-III and 32% Grade IV-V, Spetzler scale). The three methods of treatment were used, either individually or in combination, based on the size and the location of the malformation. The first intervention was surgical resection in 26% of cases, endovascular embolization in 57%, and radiosurgery in 17%. Surgery and embolization were followed by another technique in some cases and eventually single modality treatment was used in 58% of cases (surgical resection 21%, endovascular embolization 20%, radiosurgery 17%) and multimodality treatment in 42% (embolization + resection, 21%; embolization + radiosurgery, 17%; resection + radiosurgery, 4%). Embolization was used as reductive therapy in 38% of the overall series (65% of all embolized patients), and was followed by surgery in 56% of cases or by radiosurgery in 44%. Angiography was used to assess the cure rates.

RESULTS

The following cure rates were obtained, when each technique was used as a first treatment: surgical resection, 82%; embolization, 6%; and radiosurgery, 83% (2-year angiographic follow-up). After combined treatment, embolization and resection resulted in a 100% cure rate, embolization and radiosurgery produced a 90% cure rate. The clinical outcome was evaluated in terms of deterioration attributable to treatment. Seventy-one percent of patients had no complication, minor complications were observed in 18%, and severe complications in 11%. Treatment mortality was 3%. All deaths were attributable to hemorrhage during the embolization procedure.

CONCLUSIONS

In this management algorithm, AVMs submitted directly to surgery or to radiosurgery were considered "good risk" malformations, and the outcome for these cases was good in terms of clinical result and cure rate. AVMs submitted first to endovascular embolization were considered "poor risk" malformations, including a majority of Spetzler Grade IV-V lesions. Not surprisingly, the majority of severe complications occured in this group during embolization. Thus, the major risk of the treatment of AVMs has now shifted from surgery to endovascular techniques. Endovascular embolization as sole treatment gave a low rate of complete occlusion, but proved to be very useful as a reductive therapy, in preparation for further surgery or radiosurgery. Partial embolization permitted high rates of complete cure in difficult AVMs. Embolization should be used to the maximum extent possible as a reductive technique, despite the risks of the procedure. Because of its risks however, this technique of reductive embolization should be used only if absolutely necessary to allow the complete cure of the malformation. Thus, the use of embolization should be considered very cautiously in small malformations as well as in very large and complex AVMs in which partial embolization will not be sufficient to allow complete cure with either endovascular or surgical techniques.

The role of Linac radiosurgery in multidisciplinary management for cerebral arteriovenous malformations: personal experience

The authors analyze their personal series of 90 patients with cerebral arteriovenous malformations (AVMs) concerning the place of radiosurgery (RS). Out of the 90 patients, 34 undervent Linac RS-RS was used as single treatment (17%) or in combination with embolization or surgery (21%.) Eradication rate assessed angiographically after 2 years was 89%. Regarding this personal series and the recent literature, several questions remain: should small superficial AVMs revealed by hemorrhage be irradiated or operated on and the role of embolization as a reductive method before RS in order to reduce the complications and improve the obliteration rates.

First characterization of the gene RGD1 in the yeast Saccharomyces cerevisiae

We identified the ORF YBR260c during systematic sequencing of one region of chromosome II of Saccharomyces cerevisiae. This ORF encodes a putative protein of 666 aa, of which the C-terminal part of the deduced amino acid sequence resembles human and yeast Rho/Rac GTPase activating proteins (GAP). An initial study is reported in the paper. This gene was expressed in haploid and diploid cells and was called RGD1 for related GAP domain 1. Inactivation of RGD1 was carried out and phenotypic analysis of the mutant strain revealed only a slight viability defect when cells grown in minimal medium were close to stationary phase. Northern and western analyses showed that the RGD1 transcript and the corresponding protein were still abundant in cells cultivated in YNB during the stationary phase. No functional link seems to exist with the highly conserved GTPase Cdc42 involved in cytoskeletal polarization and cell polarity.

[Relaxing retinopathies and liquid perfluorocarbons]

PURPOSE

To assess the long term anatomic and functional follow-up of large relaxing retinotomies performed with liquid perfluorocarbon in severe vitreoretinal proliferation surgery.

METHODS

A large relaxing retinotomy (more than 90 degrees) was realized in 40 eyes of 39 patients for anterior vitreoretinal proliferation (30 rhegmatogen retinal detachments, 8 intraocular foreign bodies, 2 ocular traumas). Follow-up was always longer than 6 months. Vitreoretinal proliferation secondary to ischemic or inflammatory retinopathy were excluded. The liquid perfluorocarbon was perfluorodecalin and was used for all eyes, as well as final intraocular tamponade by silicon oil ended every intervention.

RESULTS

Sixty-seven % of patients had already had a former vitrectomy, and 75% a retinal surgery. Mean size retinectomy was 170 degrees. Nine patients underwent a new vitreoretinal procedure which included in 7 cases a necessary new retinectomy. Silicon oil could be removed in 55%, after a mean period of 6, 5 months. Mean time follow-up was 13 months. At the end of follow-up, 80% of retina were attached. Visual acuity remained low with 25% equal to 1/20 or more; 45% of eyes increased their acuity, 25% remained stable and 30% worsened. Main complications were epimacular proliferation, keratopathy and increased intraocular pressure.

CONCLUSION

Relaxing retinotomies provide satisfying anatomic results and allow a preservation of some visual function. The use of liquid perfluorocarbons facilitates their realization. The initial size of retinectomy should be sufficient.

Monoallelic expression of the interleukin-2 locus

The lymphokine interleukin-2 (IL-2) is responsible for autocrine cell cycle progression and regulation of immune responses. Uncontrolled secretion of IL-2 results in adverse reactions ranging from anergy, to aberrant T cell activation, to autoimmunity. With the use of fluorescent in situ hybridization and single-cell polymerase chain reaction in cells with different IL-2 alleles, IL-2 expression in mature thymocytes and T cells was found to be tightly controlled by monoallelic expression. Because IL-2 is encoded at a nonimprinted autosomal locus, this result represents an unusual regulatory mode for controlling the precise expression of a single gene.

[Surgery of intravitreous nuclear luxations post-phacoemulsification]

PURPOSE

To evaluate anatomical and functional results after surgery of retained nucleus or nuclear lens fragments into the vitreous cavity after phacoemulsification.

METHODS

Files of 46 patients that underwent vitrectomy for posterior retained nuclear fragments between July 92 and June 96 were studied retrospectively. Minimum follow-up was 6 months. Patients having only cortical material were excluded. In 34 cases the nucleus or nuclear fragments were removed posteriorly during a pars plana vitrectomy using either fragmentation with fragmatome (13 cases) or cutting with the vitreotome tip (21 cases). Anterior removal after pars plana vitrectomy was performed in 12 cases. 20 patients were operated on the first week, 12 during the second week and 14 after the second week following phacoemulsification.

RESULTS

Forty-one per cent of the patients reached 20/40 or better. 28% had less than 20/200. 8 (17%) patients presented a retinal detachment, 6 a cystoid macular edema, 6 a bullous dystrophy, and 9 an elevated intraocular pressure. At the end of follow-up 89% have been implanted (50% had been implanted at the end of the cataract surgery). We found no correlation between visual acuity and timing of surgery, anterior or posterior site removal of nuclear fragments or lens implantation during phacoemulsification.

CONCLUSION

Dislocation of the nucleus into the vitreous cavity is a serious event during phacoemulsification because of its inflammatory and retinal complications. Vitreoretinal surgery allows good visual recovery in about half of the patients. Technical handling depends primarily on the nucleus density. An IOL may be placed at the end of phacoemulsification if the nucleus is not too hard and if the anterior segment has been cleaned carefully.

Execution times of five reconstruction algorithms in 3D positron emission tomography

Various analytical, iterative and rebinning algorithms have been proposed for 3D reconstruction in positron emission tomography. This paper examines execution times of five analytical and rebinning algorithms. Meaningful comparisons are obtained by using similar software modules in all implementations. Reconstruction times are shown to differ by vast amounts: the Favor algorithm of Defrise et al is more than twice as fast as the widely used reprojection algorithm of Kinahan and Rogers; the Fourier rebinning algorithm (Fore) recently developed by Defrise is more than 15 times faster than the reprojection algorithm.

Giant cephalhaematoma in a 17-year-old boy with Ehlers-Danlos syndrome

We report a case of giant cephalhaematoma in a 17-year-old boy with Ehlers-Danlos syndrome. This haematoma occurred after a minor head injury. It increased in size, immediately after needle aspiration and was responsible for considerable blood loss. Possible physiopathological mechanisms and treatment modalities are discussed.

Onchocerciasis and Chagas' disease control: the evolution of control via applied research through changing development scenarios

This paper addresses the development of control strategies of two different parasitic diseases and identifies commonalities which have contributed to the success of regional intercountry programmes of onchocerciasis control in Africa, the Onchocerciasis Control Programme (OCP), and the new African Programme for Onchocerciasis Control (APOC) and the Chagas' Disease Control Programme in the southern cone of South America.

Discrepancies between HMPAO and ECD SPECT imaging in brain tumors

Among several brain radiopharmaceuticals for SPECT imaging, 99mTc complexes of HMPAO and ECD are the most widely used. They are considered to be equal in their capacity to reflect regional cerebral blood flow; but discrepancies between HMPAO and ECD brain uptake have been reported in stroke patients. This paper reports our observations regarding discrepancies between HMPAO and ECD SPECT in 14 of 23 patients with suspected brain tumors or presumed metabolic cerebral abnormalities. We obtained similar conflicting results, namely focal HMPAO hyperactivities and isoactive ECD SPECT. The majority of these discrepancies were found in patients with brain tumors (10 of 13 patients), while only 4 of the 10 remaining patients with nontumoral process showed similar discrepant results. The physiopathology behind these observations is discussed here, and it is likely to be related to the specific response to cellular metabolic disorders rather than to perfusion disturbances.

[Postpartum cerebral angiopathy of iatrogenic origin]

A 30 year old women, beginning her 19th day postpartum, was admitted for lowering of alertness. The day before she complained of cephalalagia. Neurologic examination showed pyramidal tract signs on the right part of the body, a bilateral Babinski sign, and central oculomotor palsy. She started a treatment by nasal pulverization of phenylephrine, a sympathomimetic vasoconstrictor, one week before, and took bromocriptine (5 mg per day) from childbirth to second week postpartum. CT scan was normal. Lumbar puncture showed a high level of proteins, from transsudative origin. Cerebral angiography showed a beading aspect of arterial branches, especially in the left middle cerebral artery territory. Two days after drug withdrawal, the patient recovered. This angiographic pattern has already been described in cases of cerebral angiopathy due to sympathomimetic drug abuse, and in cases of postpartum cerebral angiopathy. The chronology, in our case, makes the responsibility of the phenylephrine very likely. Nonetheless, ergot derivatives (i.e. ergonovine, bromocriptine) have also been accused of giving cerebral postpartum angiopathy. In our case, we think that bromocriptine may have triggered the cerebral angiopathy due to phenylephrine.

Localization of a gene coding for the phospholipase A2-L subtype (PLA2L) to human chromosome 8q24-qter

Phospholipases A2 (PLA2) form an extended class of enzymes that play an important role in signal transduction. Phospholipase A2-like (PLA2L) belongs to the secreted forms of phospholipases A2, but constitutes a new subgroup. We have assigned the gene for this enzyme to human chromosome 8q24-qter using fluorescence in situ hybridization and radiation hybrid mapping techniques.

Molecular study of nosocomial nocardiosis outbreak involving heart transplant recipients

Randomly amplified polymorphic DNA analysis and rRNA gene restriction patterns (ribotyping) were compared as methods of investigating a nosocomial outbreak of nocardiosis involving three heart transplant recipients. No clear distinctions between three clinically related isolates and four unrelated strains were obtained by ribotyping. On the contrary, randomly amplified polymorphic DNA analysis with two selected primers, primers 2650 and DKU49, showed one pattern for the three related isolates and four patterns for the unrelated strains.

Homologous DNA sequences and cellular factors are implicated in the control of glucagon and insulin gene expression

The glucagon gene is specifically expressed in the alpha cells of pancreatic islets. The promoter of the glucagon gene is responsible for this specificity. Within the promoter, the upstream promoter element G1 is critical to restrict expression to the alpha cells. We define here a composite DNA control element, G4, localized upstream of G1 between nucleotides -100 and -140 which functions as an islet-specific activator in both glucagon- and insulin-producing cells but not in nonislet cells. G4 contains at least three protein binding sites. The most proximal site, E2, is highly homologous to the E1, SMS-UE, and B elements of the rat insulin I, somastatin, and elastase I genes, respectively, and interacts with a pancreas-specific complex; the distal site, E3, represents an E box which is identical to the E boxes of the rat insulin I and II genes and binds to a complex similar or identical to IEF1 which has been implicated in the tissue-specific control of insulin gene expression. These two sites necessitate a third element, the intervening sequence, to activate transcription. We conclude that the first 140 bp of the glucagon gene promoter contains at least two DNA control elements responsible for pancreatic alpha-cell-specific expression: G4, an islet cell-specific element sharing common binding sites with the insulin gene, and G1, which restricts glucagon gene expression to the alpha cells. This double control of specificity might have relevance during islet cell differentiation.

A comparison of period amplitude and power spectral analysis of sleep EEG in normal adults and depressed outpatients

Three experiments were carried out to evaluate the relationship between two techniques for quantifying electroencephalographic (EEG) data during sleep: period amplitude analysis (PAA) and power spectral analysis (PSA). In Experiment 1, canonical correlations and regression analyses were computed on PSA and PAA data from 40 undergraduate volunteers. The results yielded an average canonical correlation of 0.98. Further, multiple regression analyses demonstrated that the PSA variables accounted for approximately 66% of the variance in the PAA data, whereas PAA variables captured 88% of the variance in the PSA data. Epoch-to-epoch correlations were higher for PAA measures than for PSA data, perhaps indicating greater stability of PSA measures across epochs of sleep. In Experiment 2, PSA and PAA data were compared in 17 unmedicated outpatients with unipolar depression. Canonical correlations and regression analyses indicated that the overlap in variance between PSA and PAA did not exceed 50%, regardless of whether PSA or PAA variables were used as predictors. Epoch-to-epoch correlations between PAA measures were significantly higher than correlations among PSA variables, again suggesting greater stability of PAA data across epochs of sleep. The range of correlations for either data set was, however, substantially lower in the depressed than in the normal group. Experiment 3 evaluated the possibility that filter settings and artifact-rejection procedures had contributed to reduced overlap in PSA-PAA variance and reduced stability in depressed patients. An additional group of eight healthy volunteers served as subjects. Findings in Experiment 3 indicated that methodological differences between Experiments 1 and 2 did not account for the reduced correlations in the depressed group. It was concluded that PSA and PAA data should be comparable in normal subjects but are relatively independent in depressed patients. Epoch-to-epoch correlations were higher for PAA data than those found between PSA measures in both normal subjects and depressed patients, suggesting that PAA may be more stable across sleep epochs. Reduced stability may be a reflection of nonstationarity in the EEG of depressed patients.

The upstream promoter element of the glucagon gene, G1, confers pancreatic alpha cell-specific expression

The glucagon gene is expressed in the endocrine pancreas, the intestine, and the brain. In the endocrine pancreas, expression of the glucagon gene is restricted to the alpha cells of the islets of Langerhans. We previously showed that 168 base pairs of the promoter was critical for this restricted expression. To further characterize the mechanisms involved in alpha cell specificity, we analyzed the responsible DNA sequences by transient transfection studies into glucagon- and insulin-producing cell lines. We localized alpha cell-specific sequences between nt 100 and 52, a region that corresponds to the upstream promoter element G1. Four protein complexes, B1, B2, B3, and B6 interact with G1; B6 requires most of G1 to be formed. B1, B2, and B3, by contrast, bind on closely overlapping sequences, display similar methylation interference patterns, and appear to be related complexes. Point mutations of G1 indicate, however, that their binding specificities are different. All four complexes are islet-specific, and impairment of their binding results in decreased transcription. We conclude that G1 interacts with islet cell-specific proteins to restrict glucagon gene expression to the alpha cells.

Islet-specific proteins interact with the insulin-response element of the glucagon gene

Glucagon gene expression is negatively regulated by insulin at the transcriptional level. G3, a DNA control element located in the 5'-flanking sequence of the rat glucagon gene mediates the inhibition of transcription, which occurs in response to insulin. We show here that two islet-specific protein complexes C1A and C1B, bind to the A domain of G3, which is critical for the insulin response. These two complexes bind to overlapping sequences of the A domain and display very similar binding specificities. Point mutations in the A domain that affect binding of C1A and C1B result in both decreased G3 enhancer activity and insulin-mediated inhibitory effects with a close correlation between diminution of binding and function. One of the two complexes, C1A, is similar or identical to B1, a protein complexes interacting with the upstream promoter element of the glucagon gene, G1, implicated in the A cell-specific expression of the glucagon gene. Our data indicate that islet-specific proteins are involved in glucagon gene regulation by insulin.

Glucagon gene expression is negatively regulated by hepatocyte nuclear factor 3 beta

Pancreatic expression of the glucagon gene depends on multiple transcription factors interacting with at least three DNA control elements: G1, the upstream promoter element, and G2 and G3, two enhancer-like sequences. We report here that the major enhancer of the rat glucagon gene, G2, interacts with three protein complexes, A1, A2, and A3. A2 is detected only in islet cells, and impairment of its binding to mutant G2 causes a marked decrease in transcriptional activity. We identify A1 as hepatocyte nuclear factor 3 beta (HNF-3 beta), a member of the HNF-3 DNA-binding protein family found in abundance in the liver which has been proposed to play a role in the formation of gut-related organs. HNF-3 beta binds G2 on a site which overlaps A2 and acts as a repressor of glucagon gene expression, as demonstrated by mutational analyses of G2 and by cotransfection of HNF-3 beta cDNA along with reporter genes containing G2 into glucagon-producing cells. Our data implicate HNF-3 beta in the control of glucagon gene expression and strengthen the idea of endodermal origin of the islet cells.

Resistance to cefotaxime and seven other beta-lactams in members of the family Enterobacteriaceae: a 3-year survey in France

During the second quarter each of 1988, 1989, and 1990, a French collaborative study group, including 12 university hospital laboratories, surveyed the resistance to beta-lactams of clinical isolates from hospitalized patients: consecutively, 10,641, 10,692, and 9,382 isolates were tested. The distribution of bacterial species over time was similar in each laboratory. The susceptibilities of microorganisms to amoxicillin, ticarcillin, cephalothin, cefoxitin, cefotaxime (CTX), ceftazidime (CAZ), aztreonam (ATM), and imipenem (IPM) were measured by the disk diffusion method in accordance with the recommendations of the Antibiogram Committee of the French Society for Microbiology. Five reference strains were included for quality control. Extended-spectrum beta-lactamases were detected by the synergistic effect of the combination of clavulanic acid-amoxicillin with CTX, CAZ, and ATM in the double-diffusion test. A synergistic effect with CTX, CAZ, and ATM was detected for 1.5% of all strains, mainly those of Klebsiella pneumoniae (13.3%). For this species, the synergy test enabled the detection of roughly 50% of the resistant strains misclassified as susceptible on the basis of interpretative standards. Extended-spectrum beta-lactamases disseminated in 1990 in most enterobacterial species but at a low frequency. Important variations in the percentages of resistant strains were observed in terms of bacterial species, hospitals, and wards. However, when the total number of strains was considered, the percentages of resistance to newer beta-lactams remained low.

[Recall of the importance of serological monitoring of children with suspected congenital toxoplasmosis]

Emphasis is put on the need for repeating serologic tests at regular intervals until one year of age in infants with suspected congenital toxoplasmosis. In 11 of 33 cases, antibody titer changes were the only evidence of toxoplasmosis, a disease which may induce severe ocular lesions if appropriate treatment is not given. Although well-recognized as indispensable, serologic monitoring is not always performed; in one group of 326 infants with suspected congenital toxoplasmosis, 133 (41%) were not followed up for more than six weeks.

Selection of unrelated donors for bone marrow transplantation is improved by HLA class II genotyping with oligonucleotide hybridization

As the demand for donors for bone marrow transplantation increases, the use of HLA-matched, genetically unrelated donors represents a promising strategy. It is well documented that the clinical outcome of bone marrow transplantation is directly dependent on optimal matching for HLA class I and class II specificities. Molecular studies have revealed the existence of a much larger number of HLA class II alleles than was anticipated, many of which cannot be recognized by routine serological typing. Currently this "hidden" polymorphism represents a major limitation to the generalized use of unrelated donors for bone marrow transplantation. It has recently become possible, however, to identify HLA allelic polymorphism directly at the DNA level by hybridization with sequence-specific oligonucleotide probes ("HLA oligotyping") after amplification of DNA by polymerase chain reaction. In this study, we have investigated whether donor-recipient pairs that are fully matched for HLA by serology are truly HLA-DR, -DQ, and -DP identical and to what extent class II differences influence the primary mixed lymphocyte culture. We show that HLA oligotyping, performed on 50 pairs of HLA class I and II serologically matched individuals, can indeed reveal phenotypically relevant allelic differences at either DRB or DQB loci in 56% of these pairs and can therefore improve HLA class II typing and the choice of bone marrow donors quite significantly. Oligotyping for DRB/DQB/DPB polymorphism also allows prediction of a positive mixed lymphocyte culture, as established in 31 donor/recipient combinations, and even detection of polymorphic differences that were not revealed by this test. This approach is well suited for accurate HLA typing of large pools of bone marrow donors and was successfully applied to select fully matched donors for bone marrow transplantation.

[In vitro antibacterial activity of a new fluoroquinolone, temafloxacin, against hospital isolates. Results of a multicenter study]

Minimal inhibitory concentrations (MICs) of temafloxacin (TMF) was determined by agar dilution for 2,510 bacterial strains isolated in 1989 in 9 university hospitals. Activity of TMF against nalidixic acid (NAL) susceptible (S) Enterobacteriaceae was close to that of other fluoroquinolones (FQ) (mode MIC: 0.06 micrograms/l); like for other FQ, this activity was reduced against NAL intermediate (mode 1) and resistant (R) (mode 4) Enterobacteriaceae. MICs of TMF against P. aeruginosa were between 0.12 and 128 (mode 0.5-1). TMF had also a good activity against NAL S A. baumannii (mode MIC: 0.06-0.12) but this activity is reduced against NAL R Acinetobacter (mode MIC: 16). TMF was highly active against Haemophilus mode MIC: less than or equal to 0.008), Gonococci (mode MIC: 0.008-0.032), Meningococci (mode MIC: 0.08) and B. catarrhalis (mode MIC: 0.016). TMF showed better activity to other fluoroquinolones against methicillin susceptible Staphylococci (mode MIC: 0.06); the resistant strains (mode MIC: 8) are usually methicillin resistant. Comparatively to the currently available FQ, TMF is so more effective against Enterococci (mode MIC: 1), Streptococci (mode MIC: 0.5-1) and Pneumococci (mode MIC: 0.5). Finally, for the anaerobic bacteria, TMF is more active against C. perfringens (mode MIC: 0.5) than against B. fragilis (mode MIC: 2).

Complete analysis of HLA-DQB1 polymorphism and DR-DQ linkage disequilibrium by oligonucleotide typing

HLA class II polymorphism is functionally important in the control of immune responses, in transplantation immunology, and in the suceptibility to autoimmune diseases. HLA-DQA1 and -DQB1 genes exhibit a larger degree of allelic polymorphism than usually recognized by routine serology. We have therefore performed an extensive analysis of DQB1 polymorphism by oligotyping. A set of 12 oligo probes was hybridized on polymerase chain reaction-amplified DNA, thus allowing the detection of 12 DQB1 alleles, as demonstrated in homozygous as well as in heterozygous individuals. This highly sensitive detection system is particularly relevant within the DQw1 specificity where the 7 allelic sequences can easily be identified. The DQ-DR linkage disequilibrium was analyzed by oligotyping of 80 Caucasoid heterozygous individuals (160 haplotypes), and very tight associations were observed between DRB1 and DQB1 alleles. Five DRB1 alleles, DR-BON, DR4/Dw4 or Dw14, DR7, DRw8.3, and DRw11, however, can be associated with different DQB1 alleles. Moreover the DRB1 and DQB1 oligotyping analysis performed on 20 randomly chosen DRw8 Caucasoid individuals showed a high prevalence of the DRB1*0801-DQB1*0402 haplotype. By combining the analysis of allelic variations at DRB1, DRB3, and DQB1 loci, we can detect 33 different DR-DQ combinations in our panel of Caucasoid individuals. We now apply DQB1 oligotyping on a routine basis for optimal matching of unrelated donors for bone marrow transplantation.

[In vitro antibacterial activity of lomefloxacin, a new fluoroquinolone, against hospital strains. Results of a multicenter study]

Minimal inhibitory concentrations (MICs) of lomefloxacin (LOM) was determined by agar dilution for 2,819 bacterial strains isolated in 1988 in 9 university hospitals. Activity of LOM against nalidixic acid (NAL) susceptible (S) Enterobacteriaceae was close to that of pefloxacin (PEF) (mode MIC: 0.12-0.25 micrograms/ml); like for PEF, this activity was reduced against NAL resistant (R) Enterobacteriaceae (mode MIC: 4). MICs of LOM against P. aeruginosa were between 0.5 and 16 (mode: 2). LOM had also a good activity against NAL S A. baumannii (mode MIC: 0.5) but this activity is reduced against NAL R Acinetobacter (MICs : 4 to 128). LOM was highly active against Haemophilus (mode MIC: 0.06), Gonococci (mode MIC: 0.008), Meningococci (mode MIC: 0.03), Branhamella (mode MIC: 0.12-0.25). LOM showed activity similar to PEF against methicillin susceptible Staphylococci (mode MIC: 0.5-1); the resistant strains are usually methicillin resistant. Similar to the currently available quinolones, LOM is less effective against L. monocytogenes (mode MIC: 8), Enterococci (mode MIC: 4), Streptococci (mode MIC: 4) and Pneumococci (mode MIC: 8). Finally, for the anaerobic bacteria, LOM is more active against Clostridium perfringens (mode MIC: 1) than against Bacteroides fragilis (mode MIC: 32).

[In vitro antibacterial activity of rokitamycin, a new macrolide antibiotic. Results of a multicenter study]

Minimal inhibitory concentrations (MIC) of rokitamycin (R) were evaluated by agar dilution for 914 bacterial strain isolated in 4 hospitals and classed as a function of susceptibility and resistance to Macrolides-Lincosamides-Streptogramines group (MLS). MICs of R ranged from 0.06 to 1 microgram/ml (mode MIC 0.25-0.5) on Staphylococci susceptible to MLS and on MLSB inducible strains; R was inactive on MLSB constitutive strains. MICs of R ranged from 0.008 to 0.5 microgram/ml (mode MIC 0.06 to 0.25) for Streptococci and Pneumococci susceptible to erythromycin (E) and from 0.06 to greater than 128 for strains resistant to E. Enterococci susceptible to E were inhibited by 0.06 to 0.5 microgram/ml (mode MIC 0.5) and strains resistant to E by 0.25 to greater than 128. Haemophilus were inhibited by 0.5 to 0.65 microgram/ml (mode MICs of R ranged generally from 0.016 to 0.5 microgram/ml (mode MIC 0.12) for C. perfringens and from 0.016 to 1 (mode MIC 0.06) for B. fragilis. Thus, R was shown to be among macrolide antibiotics of resistance strains. Its activity was superior to that of other products of this group spiramycin, josamycin, miokamycin, particularly on Gram positive cocci. R had a good activity on Neisseria, Branhamella, anaerobes and, as others macrolides, was poorly active on Haemophilus.

[Value of IgA detection in the diagnosis of toxoplasmosis]

The detection of IgA in serum by immunocapture agglutination assay is easy to perform in routine. It represents a valuable element for the diagnosis of toxoplasmosis. The presence of IgA, even more than that of IgM, evokes a recent infection. However, caution must be taken in using the results to date back the infection since kinetics of IgA production, like other immunoglobulins, may depend on individual variations.

[In vitro antibacterial activity of a new macrolide, miokamycin. Results of a multicenter study]

Minimal inhibitory concentration (MIC) of miokamycin (M) were evaluated by agar dilution for 1,024 bacterial strains isolated in 6 hospitals and classed as a function of susceptibility and resistance to macrolides, lincosamides, streptogramins group (MLS). MIC of M ranged from 0.25 to 4 micrograms/ml (mode MIC 1-2) on Staphylococcus susceptible to MLS and on MLSB inducible strains; M was inactive on MLSB constitutive strains. MIC of M ranged from 0.016 to 4 micrograms/ml (mode MIC 0.12 to 0.5) for Streptococci and Pneumococci susceptible to erythromycin (E) and from 0.12 to greater than 128 for strains resistant to E. Enterococci susceptible to E were inhibited by 0.5 to 2 micrograms/ml (mode MIC 1) and strains resistant to E by 4 to greater than 128. Haemophilus were inhibited by 2 to 64 micrograms/ml (mode MIC 32), Neisseria by 0.12 to 4 (mode MIC 0.5-1) and B. catarrhalis by 0.12 to 8 (mode MIC 1). L. pneumophila was very susceptible to M: MIC 0.016 to 0.12 (mode MIC 0.06). MIC of M ranged generally from 0.5 to 2 micrograms/ml (mode MIC 1) for C. perfringens and from 0.03 to 2 (mode MIC 1) for B. fragilis. Thus, M was shown to be among macrolide antibiotics of resistance non-inducing type on MLSB inducible resistance strains. Its activity was similar to that of spiramycin slightly superior on Staphylococci, slightly inferior on Streptococci and Enterococci, similar on Pneumococci, very superior on Neisseria, Legionella and anaerobes. M had a good activity on Branhamella and, as others macrolides, was poorly active on Haemophilus.

[Use of an antibioprophylaxis with pefloxacin and fosfomycin in cardiac surgery in patients with beta-lactam hypersensitivity]

An association of pefloxacin plus fosfomycin was used as antibioprophylaxis in beta lactam allergic patients who underwent cardiac surgery with cardiovascular-bypass. Pefloxacin (800 mg), was administered orally, one hour before anesthetic induction and fosfomycin (60 mg/kg) was injected at the time of induction. The whole course of prophylaxis wat 24 hours. Antibiotic concentrations were measured in serum before (P1, P2) during (C1, C2, C3, C4) and after cardiovascular-bypass (P3) and in bone, endocardiac and pleural tissues. The efficacy was evaluated on clinical and biological data. Antibiotic levels of pefloxacin were measured by HPLC and those of fosfomycin by bacteriological method. Antibiotic concentrations are high in blood and tissues, without evidence of cardiovascular-bypass influence. The tissue penetration of both drugs is excellent. Two patients have presented serious post-operative infections. The pharmacokinetic of pefloxacin associated with fosfomycin is appropriate during cardiovascular-bypass and the local antibiotic concentrations are above the MIC of the strains commonly responsible of post operative infections in cardiovascular surgery. The clinical efficacy of this prophylaxis must be studied in a large population of patients.

Sensitive detection and schizodeme classification of Trypanosoma cruzi cells by amplification of kinetoplast minicircle DNA sequences: use in diagnosis of Chagas' disease

Amplification of DNA sequences from the kinetoplast minicircle DNA was employed as a method for the detection and classification of small numbers of Trypanosoma cruzi cells. Two overlapping fragments from the conserved 120 bp minirepeat regions of the minicircle DNA and one fragment covering the adjacent variable regions were amplified. The minimal amount of minicircle DNA required to detect a product by hybridization with an oligonucleotide probe was 0.015 fg, which represents approximately 10 molecules or 0.1% of the minicircle DNA component of a single cell. The amplification worked equally well with kDNA from several strains of T. cruzi and did not occur with kDNA from several other kinetoplastids. kDNA recovered from less than 10 trypanosomes in whole blood could be used as a template for amplification; the presence of a several billion fold excess of human DNA had no effect on the amplification process. Schizodeme analysis by hybridization with specific oligonucleotides or by direct restriction enzyme digestion could be performed on the amplified fragments representing the minicircle conserved region or variable regions. This method should prove useful as a rapid, specific and sensitive assay for Chagas' disease in chronic patients as well as for epidemiological studies of infected animals and insects.

Evolution of parasitism: kinetoplastid protozoan history reconstructed from mitochondrial rRNA gene sequences

A phylogenetic tree for the evolution of five representative species from four genera of kinetoplastid protozoa was constructed from comparison of the mitochondrial 9S and 12S rRNA gene sequences and application of both parsimony and evolutionary parsimony algorithms. In the rooted version of the tree, the monogenetic species Crithidia fasciculata is the most deeply rooted, followed by another monogenetic species, Leptomonas sp. The three digenetic species Trypanosoma cruzi, Trypanosoma brucei, and Leishmania tarentolae branch from the Leptomonas line. The substitution rates for the T. brucei and T. cruzi sequences were 3-4 times greater than that of the L. tarentolae sequences. This phylogenetic tree is consistent with our cladistic analysis of the biological evidence including life cycles for these five species. A tentative time scale can be assigned to the nodes of this tree by assuming that the common ancestor of the digenetic parasites predated the separation of South America and Africa and postdated the first fossil appearance of its host (inferred by parsimony analysis). This time scale predicts that the deepest node occurred at 264 +/- 51 million years ago, at a time commensurate with the fossil origins of the Hemiptera insect host. This implies that the ancestral kinetoplastid and its insect host appeared at approximately the same time. The molecular data suggest that these eukaryotic parasites have an evolutionary history that extends back to the origin of their insect host.

[In vitro antibacterial activity of apalcillin on aerobic bacteria and the regression curve]

Minimal inhibitory concentrations (MICs) of apalcillin (APL) were evaluated by agar dilution on 1,201 bacterial strains isolated simultaneously in four university hospitals; agar diffusion tests (disks APL: 75 micrograms) were performed on these strains to establish relationship between MIC and zone diameters. For Enterobacteriaceae naturally non beta-lactamase-producing (E. coli and P. mirabilis), mode MIC was 0.5 microgram/ml; some acquired penicillinase-producing strains were only inhibited by concentrations greater than or equal to 16. Chromosomal penicillinase producing Klebsiella were inhibited by 2 to 8 micrograms/ml but APL was inactive on acquired penicillinase-producing strains. For chromosomal cephalosporinase-producing species (Enterobacter, Citrobacter, Serratia, indole + Proteus and Providencia) two populations of strains were observed: one sensitive and the second resistant to carboxypenicillins: on the first population, mode MIC of APL was 1 to 4 micrograms/ml; on the second MIC were generally greater than or equal to 64 micrograms/ml. P. aeruginosa strains sensitive to carboxypenicillins were inhibited by 1 and 2 micrograms/ml; this activity was diminished on strains resistant to these antibiotics (MIC APL 8-32). MIC of Acinetobacter varied to 0.25 to greater than 128 with a majority of strains inhibited by 4 to 64 micrograms/ml. APL was active against non penicillinase producing Staphylococci; mode MIC was 2 micrograms/ml for Enterococci. Correlation coefficient of regression curve was 0.87. For critical concentrations less than or equal to 8 and greater than 64 micrograms/ml, critical diameters could be greater than or equal to 19 and less than 12 mm.

Reversible effects of long-term treatment with D-Trp6-LH-RH-microcapsules on pituitary-gonadal axis, spermatogenesis and prostate morphology in adolescent and adult dogs

The effect of long term treatment with D-Trp6-LH-RH in microcapsules (GnRH-A) on pituitary gonadal axis was studied in a adolescent and adult Fox-terrier dogs. They received intramuscularly 50 micrograms/GnRH-A/kg, on day 1 and 21 and every 4 weeks thereafter. Three adult dogs received 4 injections. cLH, cFSH and T levels were undetectable on day 7. Detectable then normal levels occurred 60 and 90 days respectively after the last injection on day 77. Testis thickness was respectively 22.1 +/- 0.8 mm and 16.3 +/- 0.8 mm on days 0 and 77; initial values were observed 90 days later. Spermatozoa disappeared from the ejaculate on day 21 in 2 dogs; reappearance and complete recovery were observed on days 161-175 and 252 respectively. Histological findings showed on day 91 atrophic lesions of testis and prostate and spermatogonia were present in all seminiferous tubules. After recovery a normal histological appearance was noticed. Three adolescent 29 weeks old dogs received 14 injections, the last one on day 357. cLH, cFSH and T levels were undetectable only from day 105. Testis thickness were respectively 15.8 +/- 0.7 mm, 18.1 +/- 0.7 mm, 12.5 +/- 0.3 mm and 21.4 +/- 0.7 mm on day 0, 21, 357 and 490. Initially, no spermatozoa were present in the ejaculates, they appeared in 2 dogs after 2 months for 20 to 40 days then disappeared until day 449. Normal semen characteristics were observed in all three dogs on day 581. Histological findings on day 371 were comparable to those observed in the adult dogs. This study demonstrates that longterm treatment with D-Trp6-LH-RH in microcapsules leads to a reversible inhibition of spermatogenesis in dogs. The delayed response in adolescent dogs might be due to a transient resistance to therapy related to.

[Diffusion, in the bronchial mucus, of enoxacin administered by oral route in man]

The diffusion of Enoxacin into the bronchial mucus was studied in 34 patients admitted because of an acute infectious episode over chronic bronchopathy. They received via the oral route 400 mg of Enoxacin twice daily. The antibiotic concentrations were measured in sputum and serum by microbiological assay and HPLC. The patients were divided into 5 groups according with the timing of sampling: 1, 3, 6, 12 hours after dosing at day 3 (group I, II, III, IV), 3 hours after dosing at day 1, 2 and 3 (group V). Serum concentrations of Enoxacin were low (2.46 mg/l at 3rd hour). Bronchial concentrations exceed blood levels (mean 3.06 mg/l at 3rd hour). The bronchial levels of Enoxacin were above the mean MIC of many respiratory bacterial pathogens.

[Effectiveness of piperacillin in the antibacterial treatment of intra-abdominal infections in children]

The effectiveness of piperacillin was investigated in 30 children operated upon for peritonitis: 13 had acute appendicitis with puriform peritoneal reaction, or a recently perforated appendix; 5 had generalized peritonitis of appendicular origin, and 13 had intraperitoneal abscess. In the 12 children who underwent right iliac appendicectomy (with post-operative drainage in 3), piperacillin was administered alone during 5 days; clinical and bacteriological cure was obtained in all cases; the mean duration of stay in hospital was 7 days. The 5 cases of generalized peritonitis required drainage; piperacillin was given alone in 4 of them and combined with an aminoglycoside and metronidazole in one who was in poor general condition. Bacteriology showed a predominance of Escherichia coli alone or associated with other organisms. Clinical and bacteriological cure was obtained in 3 patients; the mean duration of stay in hospital was 12 days. Seven of the 13 cases of intraperitoneal abscess needed drainage. Piperacillin was administered alone for 7 days on average in 10 cases and combined with an aminoglycoside and metronidazole in 2 cases. Eight patients had a favourable course, 5 developed complications. In all 3 groups piperacillin was tell tolerated. A patch of urticaria was noted in 2 cases and a transient skin rash in 2 other cases. No neutropenia was observed in these children whose treatment never exceeded 10 days.