[Streptococcus pneumoniae cellulitis in a diabetic patient]

Pneumococcal cellulitis is an uncommon infection. Head, neck, and trunk are usually affected in patients with hematological malignancies and lupus erythematosus. Limb cellulitis is frequently observed in patients with diabetes mellitus, drug abusers, or alcoholics. Patients present with septic shock most of the time. Surgical treatment is necessary in 50% of the cases. The outcome is usually favorable. We describe the case of a 72-year-old alcoholic patient with diabetes mellitus presenting with cellulitis and septic shock. Serotype 19 Streptococcus pneumoniae with abnormal susceptibility to penicillin (MIC: 0.75 mg/l) was isolated from cellulitis and in blood culture. The evolution was favorable after itavenous antibiotherapy combining ceftriaxone(DCI) (2 g/j), metronidazole(DCI) (1 g/j), and ciprofloxacin(DCI).

[Outcome of surgical and adjuvant radiotherapy treatment of T3-T4 squamous cell carcinoma of the floor of the mouth: evaluation of oncological control and treatment related morbidity]

OBJECTIVE

The aims of this study were to evaluate the therapeutic outcome and morbidity associated with management of squamous cell carcinoma (SCC) T3-T4 of the floor of the mouth.

PATIENTS AND METHODS

This was a retrospective study (1993 and 2005). Inclusion criteria were: 1) Presence of a locally advanced (T3-T4) lesion of the floor of the mouth; 2) Pathological confirmation of SCC; 3) No previous treatment of the floor of the mouth; 4) Absence of any synchronous lesions at the primary endoscopic work-up; 5) Absence of distant metastasis outside the aero-digestive tract; 6) Karnofsky performance index > 70. All patients were treated by surgery and adjuvant radiotherapy. The statistical analysis was conducted using the stat-view software; categorical variables were compared using the Fisher's exact test; analysis of recurrence-free survival rate was done following the Kaplan-Meier method, and the log-rank test was used for the comparison of survival graphs.

RESULTS

Fourty-seven patients were included in this study (42 men), of a mean age of 53.3 years. The majority of patients (93.6%) presented with a stage IVa tumour and no clinical evidence of cervical lymphadenopathy in 60% of cases. All patients underwent bilateral neck dissection adapted to the cervical lymph node status. Forty-one (87%) patients underwent partial mandibulectomy with fibula free-flap reconstruction in 32 cases (78%). Early local complication rate was of 32%. The mean duration of hospitalization was 34 days. Late local complication rate was of 17%. The immediate post-operative death rate was 2%. The rate of survival and recurrence free survival was of 47.5% and 47% respectively. The 3 survival-influencing factors were age (p = 0.02), margins of surgical resection (p = 0.002), and histologic cervical lymph node status (p = 0.03).

CONCLUSION

T3-T4 tumours of the floor of the mouth are managed by surgical resection and adjuvant radiotherapy. There is a high rate of treatment-associated complications. The prognosis of locally advanced tumours of the floor of the mouth remains humble.

Amyloid precursor protein cytoplasmic domain antagonizes reelin neurite outgrowth inhibition of hippocampal neurons

The function of the amyloid precursor protein (APP), a key molecule in Alzheimer's disease (AD) remains unknown. Among the proteins that interact with the APP cytoplasmic domain in vitro and in heterologous systems is Disabled-1, a signaling molecule of the reelin pathway. The physiological consequence of this interaction is unknown. Here we used an in vitro model of hippocampal neurons grown on a reelin substrate that inhibits neurite outgrowth. Our results show that an excess of APP cytoplasmic domain internalized by a cell permeable peptide, is able to antagonize the neurite outgrowth inhibition of reelin. The APP cytoplasmic domain binds Disabled-1 and retains it in the cytoplasm, preventing it from reaching the plasma membrane and sequesters tyrosine phosphorylated Disabled-1, both of which disrupt reelin signaling. In the context of AD, increased formation of APP cytoplasmic domain in the cytosol released after cleavage of the A beta peptide, could then inhibit reelin signaling pathway in the hippocampus and thus influence synaptic plasticity.

Control of neuronal branching by the death receptor CD95 (Fas/Apo-1)

The CD95 (Apo-1/Fas)/CD95 ligand (CD95L) system is best characterized as a trigger of apoptosis. Nevertheless, despite broad expression of CD95L and CD95 in the developing brain, absence of functional CD95 (lpr mice) or CD95L (gld mice) does not alter neuronal numbers. Here, we report that in embryonic hippocampal and cortical neurons in vivo and in vitro CD95L does not induce apoptosis. Triggering of CD95 in cultured immature neurons substantially increases neurite branches by promoting their formation. The branching increase occurs in a caspase-independent and death domain-dependent manner and is paralleled by an increase in the nonphosphorylated form of Tau. Most importantly, lpr and gld mutants exhibit a reduced number of dendritic branches in vivo at the time when synapse formation takes place. These data reveal a novel function for the CD95 system and add to the picture of guidance molecules in the developing brain.

Disruption of ephrin-A/EphA binding alters synaptogenesis and neural connectivity in the hippocampus

Ephrins are guidance cues that modulate axonal growth and the subsequent axonal topographic maps in many regions of the CNS. Here we studied the functional roles of ephrin-A/EphA interactions in the layer-specific pattern of axonal projections in the hippocampus by disrupting the ephrin-A signaling by over-expression of a soluble EphA receptor. Tracing experiments in EphA5-Fc over-expressing mice revealed that reduction of ephrin-A/EphA interactions did not affect the proper distribution of the main hippocampal afferents, i.e. entorhinal and commissural projections. However, further ultrastructural analyses showed a reduction in the density of synaptic terminals in the entorhinal and commissural termination layers in these mice. In addition, using anti-calbindin antibodies, we analyzed the dentate mossy fiber projections following disruption of ephrin-A/EphA interactions throughout developing hippocampus. While the main mossy fiber bundle appeared normal, the infrapyramidal bundle formed longer projections that established ectopic contacts in these transgenic mice. Later, the expected specific pruning of the infrapyramidal bundle was not observed at adult stages. Ultrastructural analyses confirmed a higher number of mossy fiber terminals in the infrapyramidal bundle in adult EphA5-Fc transgenic mice and showed that these terminals were larger and established a greater number of contacts than in controls. Our results demonstrate that ephrin-A/EphA interactions regulate the synaptogenesis of hippocampal afferents and the proper development and refinement of granule cell projections.

Expression of discoidin domain receptor 1 during mouse brain development follows the progress of myelination

Discoidin domain receptor 1 is a tyrosine kinase receptor expressed in a variety of tissues including the brain. This study describes mRNA and protein expression of discoidin domain receptor 1 in mouse brain during development and provides new insights into its role during gliogenesis and neurogenesis. We performed in situ hybridization for discoidin domain receptor 1 in mouse brains at embryonic day 18, postnatal days 5, 9, 15, 21 and adulthood and observed a diffuse pattern in the proliferative areas during embryogenesis. From postnatal day 5 onwards, a defined cellular expression pattern of discoidin domain receptor 1 was observed, mainly located in white matter tracts and following a spatio-temporal pattern that overlapped the progress of myelination. Next, we performed double-labeling reactions (in situ hybridization followed by immunohistochemistry) that confirmed that discoidin domain receptor 1 was expressed by mature oligodendrocytes. We observed that cells positive for discoidin domain receptor 1 also expressed carnosine and anti-adenomatous polyposis coli, two mature oligodendrocyte markers. Based on the localization of discoidin domain receptor 1 specifically in the white matter fiber tracts during postnatal development, we suggest that discoidin domain receptor 1 participates in the development and maintenance of the myelin sheath.

[Combined induction chemotherapy and radiotherapy in case of undifferentiated carcinoma of nasopharynx tumours (UCNT)]

OBJECTIVE

The objectives of our study were to consider the morbidity and the effectiveness of combined induction chemotherapy and radiotherapy in the treatment of Undifferentiated Carcinoma of Nasopharynx Tumor (UCNT).

PATIENTS AND METHODS

It was a retrospective study (1987-2002) of patients who had not received any previous treatment. Patients with distant metastases during initial assessment were excluded. Two types of chemotherapy were administered: The BAC regime (Bleomycin, Adriamycin, Cisplatinum) and the FUCIFOL regime (Fluorouracil, Cispaltinum, Elvorin). The protocol for radiotherapy was either radiotherapy alone or concomitant chemoradiotherapy. The survival rates were calculated with the nonparametric method of Kaplan-Meier and compared with logrank tests. The multivariate analysis were made with the regressive logistic method.

RESULTS

Fourty four patients (32 males, 12 females), average age 46 years (14-77) were selected. On the whole, the tolerance of the treatment was good (chemotherapy 71%, radiotherapy 82%). Treatment mortality was null. The BAC regime was the most effective. At the end of the treatment, a total response was obtained in 82% of cases. The commonest cause of treatment failure was the emergence of metastases (64% of deaths). The overall disease free survival rates at 3 years were respectively 78% and 69%. With multivariate analysis, the independent variables inductive radiotherapy and the initial response to treatment were significantly linked to death with a respective p value of 0.02 and 0.0084.

CONCLUSIONS

Combined induction chemotherapy and radiotherapy is efficient in the treatment of UCNT. The tolerance of treatment was good. Our results are comparable with those reported in the literature.

Ephrin-A5 modulates the topographic mapping and connectivity of commissural axons in murine hippocampus

Entorhinal and commissural/associational projections show a non-overlapping distribution in the hippocampus proper and the dentate gyrus. The expression of Ephrins and their Eph receptors in the developing hippocampus indicates that this family of axonal guidance molecules may modulate the formation of these connections. Here we focused on the role of the ephrin-A5 ligand in the development of the main hippocampal afferents. In situ hybridization showed that ephrin-A5 mRNA was detected mainly in the principal cells of the hippocampus proper and in the dentate gyrus throughout postnatal development. Immunocytochemical analyses revealed prominent expression of the EphA3 receptor, a putative receptor for ephrin-A5, in the main cells and the neuropil of the developing hippocampus. Tracing experiments in ephrin-A5(-/-) mice showed that commissural projections were transiently altered in the hippocampus proper at P5, but they were mistargeted throughout the postnatal development in the dentate gyrus. Immunocytochemistry with anti-calbindin antibodies revealed that the dentate mossy fiber projection was not altered in ephrin-A5(-/-) mice. Electron microscopy studies showed alterations in the density of synapses and spines in commissural/associational layers, but not in entorhinal layers, and in the mossy fibers in these animals. Taken together, these findings indicate that ephrin-A5 signaling is involved in the formation and maturation of synapses in the hippocampus.

Reconstruction après résection tumorale de la base antérieure du crâne par greffon graisseux abdominal

OBJECTIVES

Reconstruction of the anterior skull base is a surgical stage as significant as tumor removal. The quality of the reconstruction is the primary determinant of postoperative mortality, morbidity. The aim of our work was to assess the results of a reconstruction process combining: 1) a pericranium graft held by biological glue to complete the dura mater; 2) an abdominal fat graft supported by a Silastic arch to maintain the neurological structures.

PATIENTS AND METHODS

This was a retrospective study. 55 patients (44 men and 11 women), 59 mean age (14 - 78), were analyzed. 45 had a malignant tumor and 10 a benign tumor. 35 patients were treated using a mixed approach and 18 using a trans frontal-sinus approach alone. Forty-three patients treated for a malignant tumor underwent postoperative radiotherapy. Results were analyzed according to 3 periods: 1) immediate postoperative period (<25 days); 2) early postoperative period (25 days - 3 months); 3) late postoperative period (> 3 months).

RESULTS

None of the patients were lost to follow-up. The average follow up was 84 months. All periods considered together, we had five (9.4%) graft infections, 6 (11.3%) CSF leaks and 1 (1.8%) cases of meningitis.

CONCLUSION

We use a simple technique for reconstruction. Postoperative complications were exceptional, even after postoperative radiotherapy. Medium and long-term results are good and similar to those obtained with other processes used for reconstruction of the anterior skull base reconstruction.

Evolution et pronostic du carcinome basaloïde squameux des voies aéro-digestives supérieures

INTRODUCTION

The course and prognosis of basaloid squamous cell carcinoma (BSCC) are not well known.

OBJECTIVES

To study the course and prognosis in a population of BSCC patients.

MATERIALS AND METHODS

We analyzed a retrospective cohort of 49 patients with BSCC in comparison with a cross-matched population of 49 patients treated for well- to moderately differentiated squamous cell carcinoma (SCC).

RESULTS

The statistical analysis showed that survival in BSCC group was lower than in the SCC group. Local recurrence in the BSCC group was not higher than in the SCC group, but mortality by distant metastasis was six times higher than in the SCC population.

CONCLUSIONS

We consider BSCC patients as a high-risk population and we complete diagnosis explorations including a FDG-PET before curative treatment. We also recommend post-operative or exclusive radiotherapy which may be associated with concomitant chemotherapy.

Fractures de l’angle mandibulaire : facteurs prédictifs des complications infectieuses

INTRODUCTION

Fractures of the mandible angle raise the risk of infectious complications. We searched for factors predictive of these complications.

MATERIAL AND METHODS

We reviewed retrospective all cases of mandibular angle fracture treated during a 26-month period. We compared two groups: fractures with wisdom teeth and fractures without wisdom tooth. For each group we noted clinical and radiological characteristics of the fractures and infectious complications.

RESULTS

The series included 72 mandibular angle fractures, 30 with a wisdom tooth against 42 without. Most of the patients were treated within 2 days, generally using mini-plate screw fixation. In the wisdom tooth group, 16.6% of patients developed infectious complications versus 9.5% in the without wisdom tooth group. All patients of the wisdom tooth group presented a potentially infectious focus on the preoperative x-rays. For without wisdom tooth group, irregular follow-up was found to be the only risk factor.

DISCUSSION

The angular localization increases the risk of infectious complications especially if the wisdom tooth is in the fracture. We propose a decision tree to determine when to preserve or not the wisdom tooth.

[The outcome of treatments for carcinoma of the external auditory canal]

OBJECTIVE

A retrospective analysis of management and survival of patients treated for temporal bone carcinoma.

PATIENTS AND METHODS

Thirty patients underwent treatment for carcinoma of the temporal bone. Twenty-five squamous cell carcinomas, 1 melanoma, 2 basocellular carcinomas and 2 adenoid cystic carcinomas were treated. Thirteen patients were treated before for the same disease.

RESULTS

Staging revealed 12 T1 and T2, 6 T3 and 12 T4 tumours. The mean follow up was 5 years (2-276 months). The Kaplan Meier survival curves showed survival rates at 2 years of 82%, 67% and 32%, and at 5 years of 82%, 67% and 17%, respectively for the stages T1 or T2, T3 and T4. At the end of follow up at 9 years the survival rates were 66%, 66% and 17% for the stages T1 or T2, T3 and T4 respectively. Overall stages a complete remission was found in 65% and 23%, and deceased was 35% and 77%, respectively for the primary treatment group and the salvage surgery group.

CONCLUSION

Long-term prognosis of the carcinoma of the external auditory canal mainly depends on the stage and primary treatment. Surgery (lateral temporal bone or subtotal temporal bone resection, both in combination with a neck dissection and a parotidectomy) and adjuvant radiotherapy is the treatment of choice for part of stage T1 and all T2 and T3 tumours. The improved survival (65%) of patients treated de novo compared with those treated with salvage surgery (23%) suggests that early referral and aggressive primary surgical treatment with postoperative radiotherapy offer the greatest chance of cure.

Msx1 expression in the adult mouse brain: characterization of populations of beta-galactosidase-positive cells in the hippocampus and fimbria

We have analyzed Msx1 expression in the mature mouse brain using in situ hybridization and beta-galactosidase activity in Msx1(nLacZ) mice. The study revealed that Msx1 is strongly expressed in the circumventricular organs, such as the subcommissural organ and choroid plexus, and in some epithelia, such as that of the dorsal, but not the ventral part of the third ventricle. Immunohistochemical analysis revealed that the Msx1-expressing cells of the hippocampus and fimbria are astrocytes, oligodendrocytes or immature oligodendrocytes. In contrast, no co-expression was detected in these structures using several neuronal markers. These results were confirmed, using transmission electron microscopy, by the presence of 5-bromo-3-indolyl-beta-D-galactopyranosideprecipitates in astrocytes and oligodendrocytes in both sites. Moreover, using an anti-glial fibrillary acidic protein antibody (GFAP), our study reveals two populations of astrocytes in the adult hippocampus and other areas, such as the fimbria, namely Msx1+/GFAP+ and Msx1-/GFAP+. Beta-galactosidase activity was also observed in endothelial cells of hippocampal fissure blood vessels. We also observed co-localization of polysialic acid neural cell adhesion molecule, a marker of the polysialylated form of the neural cell adhesion molecule, in Msx1-expressing cells in the fimbria. These cells may be precursors of glial cells and originate from the epithelium of the fimbria. The present study indicates, in the mature mouse brain, that Msx1 may be linked to secretory activity in circumventricular organs, and to glial proliferation and differentiation in the hippocampus and fimbria, and presumably also in other cerebral areas. We suggest that Msx1 could be associated with brain homeostasis and blood-brain barrier function.

Msx1-Deficient Mice Fail to Form Prosomere 1 Derivatives, Subcommissural Organ, and Posterior Commissure and Develop Hydrocephalus

Msx1 is a regulatory gene involved in epithelio-mesenchymal interactions in limb formation and organogenesis. In the embryonic CNS, the Msx1 gene is expressed along the dorsal midline. Msx1 mutant mice have been obtained by insertion of the nlacZ gene in the Msx1 homeodomain. The most important features of homozygous mutants that we observed were the absence or malformation of the posterior commissure (PC) and of the subcommissural organ (SCO), the collapse of the cerebral aqueduct, and the development of hydrocephalus. Heterozygous mutants developed abnormal PC and reduced SCO, as revealed by specific antibodies against SCO secretory glycoproteins. About one third of the heterozygous mutants also showed hydrocephalus. Other defects displayed by homozygous mutants were ependymal denudation, subventricular cavitations and edema, and underdevelopment of the pineal gland and subfornical organ. Some homozygous mutants developed both SCO and PC, probably as a consequence of genetic redundancy with Msx2. However, these mutants did not show SCO-immunoreactive glycoproteins and displayed obstructive hydrocephalus. This suggests that Msx1 is necessary for the synthesis of SCO glycoproteins, which would then be required for the maintenance of an open aqueduct.

[Congenital nasal pyriform aperture stenosis: a case report]

Congenital nasal pyriform aperture stenosis is a rare and poorly understood pathology. It's etiology is unknown. In cases with severe nasal airway obstruction, this anomaly may produce newborn respiratory destress similar to those seen in bilateral posterior choanal atresia. It can occur as an isolated anomaly or it can be associated with a dental anomaly, craniofacial, ophthalmological or central nervous system malformation. The diagnosis is made by physical examination. Computed tomography confirms the diagnosis. Magnetic resonance imaging of the brain and pituitary endocrine axis must be performed. In patients with severe obstruction, surgical correction is necessary. We describe the case of a 1-month-old child who needed surgical treatment with a sublabial approach for a congenital nasal pyriform aperture stenosis associated with a solitary maxillary central incisor. The follow-up (4 years) reveals normal nasal airway and facial growth.

[Transmandibular buccopharyngectomy after radiotherapy for orpharyngeal cancer]

MATERIALS & METHODS

We present a retrospective study of 95 patients with recurrence of oropharyngeal carcinoma after exclusive radiotherapy. The treatment consisted in a salvage composite resection in all cases.

RESULTS & DISCUSSION

Since the use of muscular flaps, the post-operative complications have been relatively minimised but the carcinologic results were disappointing: only 20% of patients were alive free of disease at 5 years. The main prognostic factors for overall survival were the stage rT of the relapse, the histologic invasion of the nodes and the quality of the resection. The anatomic site of relapse did not influence the survival.

CONCLUSION

Our serie confirms the high frequency of second primary tumors in oropharyngeal cancers. Rigorous selection of patients for exclusive radiotherapy is mandatory to decrease the number of relapses and might avoid salvage surgery.

Decreased invasive capacity of quinolone-resistant Escherichia coli in patients with urinary tract infections

Quinolone-resistant (QR) Escherichia coli may have lower invasive capacity than does quinolone-susceptible E. coli. To evaluate this, we prospectively collected data regarding all cases of E. coli invasive urinary tract infections (IUTI) in 669 adults admitted to the Infectious Diseases Unit of our hospital during a 3-year period, as well as 10,950 patients with cystitis or asymptomatic bacteriuria who presented to the outpatient clinic during a 1-year period. QR E. coli was isolated in 20% of patients with cystitis, compared with 8% of those with IUTI (P<.05). The proportion of E. coli isolates that were quinolone resistant was similar in patients with bacteremic and nonbacteremic IUTI. The factors of urinary manipulation and structural abnormalities were independently associated with the presence of quinolone resistance. Old age was the only variable independently associated with blood invasion. QR E. coli is less likely to produce invasive disease (pyelonephritis and prostatitis) than is quinolone-susceptible E. coli. However, once pyelonephritis or prostatitis have developed, there is no difference in the incidence of bacteremia.

The reelin pathway modulates the structure and function of retinal synaptic circuitry

The formation of synaptic connections requires the coordination of specific guidance molecules and spontaneous neuronal activity. The visual system has provided a useful model for understanding the role of these cues in shaping the precise connections from the neural retina to the brain. Here, we demonstrate that two essential genes in the Reelin signaling pathway function during the patterning of synaptic connectivity in the retina. Physiological studies of mice deficient in either reelin or disabled-1 reveal an attenuation of rod-driven retinal responses. This defect is associated with a decrease in rod bipolar cell density and an abnormal distribution of processes in the inner plexiform layer. These results imply that, in addition to its essential role during neuronal migration, the Reelin pathway contributes to the formation of neuronal circuits in the central nervous system.

Detection of unsuspected cases of nosocomial transmission of tuberculosis by use of a molecular typing method

The aim of this study was to use restriction fragment length polymorphism to detect unsuspected cases of nosocomial transmission of tuberculosis (TB) among patients who had been admitted to a university hospital. One hundred fifty-one samples of Mycobacterium tuberculosis isolated from patients with pulmonary TB were studied. The isolates from 37 patients (24.5%) defined 11 clusters. None of the patients infected with these cluster isolates had hospital stays that coincided with one another, and for 5.4% of the patients, the epidemiological link was clearly outside the hospital. Previous incarceration was associated with infection with cluster isolates. In addition, 109 patients without TB (41 of whom were infected with human immunodeficiency virus) who shared a room with patients who had TB were followed for 18-60 months. Among the patients who survived, secondary cases of TB due to nosocomial transmission were not detected.

Pattern of expression of the tetraspanin Tspan-5 during brain development in the mouse

Here, we report the pattern of expression of the tetraspanin mTspan-5 at various developmental stages. Expression was first seen at E10 and remained until adulthood, with increased levels between P0 and P5. mTspan-5 showed high expression in the cortical areas and Purkinje cells throughout development. Moreover, transcripts were also detected in the developing heart, forelimbs, and hindlimbs.

Age-dependent effects of secreted Semaphorins 3A, 3F, and 3E on developing hippocampal axons: in vitro effects and phenotype of Semaphorin 3A (-/-) mice

We studied the role of Semaphorins in the formation of hippocampal connections at embryonic and early postnatal stages. We show that the embryonic entorhinal cortex has a repulsive effect on embryonic hippocampal axons that disappears gradually at postnatal stages. Such chemorepulsion is blocked by Neuropilin-1 and -2 blocking antibodies. However, at perinatal stages, the inner layers of the entorhinal cortex attract CA1 axons. At these stages, Sema3A and Sema3F bind commissural and entorhinal axons. Sema3A and Sema3F repel hippocampal axons at E14-P2, but not at E13. A similar spatiotemporal pattern of chemorepulsion is observed for Sema3A on entorhinal axons, in contrast to Sema3F, which repels these axons only at postnatal ages. Sema3E also repels hippocampal axons but exclusively at E14. We show that Sema3A and Sema3F can induce the collapse of hippocampal growth cones and that membrane-bound Sema3A and Sema3F can guide hippocampal axons in the stripe assay. In sema3A (-/-) mice, the entorhinohippocampal projection is largely normal although single axons innervate aberrantly the stratum radiatum and the hilus. Thus, the chemorepulsion evoked by Sema3A, Sema3E, and Sema3F is dynamically regulated in the developing hippocampal formation.

Plasmin-mediated release of the guidance molecule F-spondin from the extracellular matrix

Serine proteases are implicated in a variety of processes during neurogenesis, including cell migration, axon outgrowth, and synapse elimination. Tissue-type plasminogen activator and urokinase-type activator are expressed in the floor plate during embryonic development. F-spondin, a gene also expressed in the floor plate, encodes a secreted, extracellular matrix-attached protein that promotes outgrowth of commissural axons and inhibits outgrowth of motor axons. F-spondin is processed in vivo to yield an amino half protein that contains regions of homology to reelin and mindin, and a carboxyl half protein that contains either six or four thrombospondin type I repeats (TSRs). We have tested F-spondin to see whether it is subjected to processing by plasmin and to determine whether the processing modulates its biological activity. Plasmin cleaves F-spondin at its carboxyl terminus. By using nested deletion proteins and mutating potential plasmin cleavage sites, we have identified two cleavage sites, the first between the fifth and sixth TSRs, and the second at the fifth TSR. Analysis of the extracellular matrix (ECM) attachment properties of the TSRs revealed that the fifth and sixth TSRs bind to the ECM, but repeats 1-4 do not. Structural functional experiments revealed that two basic motives are required to elicit binding of TSR module to the ECM. We demonstrate further that plasmin releases the ECM-bound F-spondin protein.

Dscr1, a novel endogenous inhibitor of calcineurin signaling, is expressed in the primitive ventricle of the heart and during neurogenesis

We have demonstrated that DSCR1 acts as a negative regulator of calcineurin-mediated signaling and that its transcript is overexpressed in the Down syndrome (DS) fetal brain. To evaluate the possible involvement of DSCR1 in DS, we have cloned the mouse gene and analyzed its expression pattern in the central nervous system (CNS). Early expression of Dscr1 is detected mainly in the heart tube and in the CNS in rhombomere 4 and the pretectum. From embryonic day 14.5 onwards, Dscr1 is widely distributed in the CNS but becomes more restricted as the brain matures. We confirmed its neuronal expression pattern in the adult, preferentially in Purkinje and pyramidal cells, by double labeling with glial fibrillary acidic protein. We also show that although Dscr1 is present in trisomy in the Ts65Dn mouse, the adult brain expression pattern is not significantly altered. This expression pattern indicated that Dscr1 is a developmentally regulated gene involved in neurogenesis and cardiogenesis and suggests that it may contribute to the alterations observed in these organ systems in DS patients.

Long-term controlled trial of nocturnal nasal positive pressure ventilation in patients with severe COPD

STUDY OBJECTIVES

To determine the 1-year efficacy of noninvasive positive pressure ventilation (NPPV) added to long-term oxygen therapy (LTOT) in patients with stable severe COPD. PATIENT SELECTION AND METHODS: We prospectively randomized 52 patients with severe COPD (FEV(1) < 45%) to either NPPV plus "standard care" (96% patients with LTOT) or to standard care alone (93% patients with LTOT). The outcomes measured included the following: rate of acute COPD exacerbations; hospital admissions; intubations; and mortality at 3 months, 6 months, and 12 months. The patients were also evaluated at 3 months and 6 months for dyspnea using the Medical Research Council and Borg scales, gas exchange, hematocrit, pulmonary function, cardiac function with echocardiogram, and neuropsychological performance.

RESULTS

One-year survival was similar in both groups (78%). The number of acute exacerbations was similar at all time points in patients receiving NPPV, compared with control subjects. The number of hospital admissions was decreased at 3 months in the NPPV group (5% vs 15% of patients, p < 0.05), but this difference was not seen at 6 months (18% vs 19%, respectively). The only beneficial differences were observed in the Borg dyspnea rating, which dropped from 6 to 5 (p < 0.039), and in one of the neuropsychological tests (psychomotor coordination) for the NPPV group at 6 months.

CONCLUSIONS

Our study indicates that over 1 year, NPPV does not affect the natural course of the disease and is of marginal benefit in outpatients with severe COPD who are in stable condition.

Aberrant development of hippocampal circuits and altered neural activity in netrin 1-deficient mice

Diffusible factors, including netrins and semaphorins, are believed to be important cues for the formation of neural circuits in the forebrain. Here we have examined the role of netrin 1 in the development of hippocampal connections. We show that netrin 1 and its receptor, Dcc, are expressed in the developing fimbria and in projection neurons, respectively, and that netrin 1 promotes the outgrowth of hippocampal axons in vitro via DCC receptors. We also show that the hippocampus of netrin 1-deficient mice shows a misorientation of fiber tracts and pathfinding errors, as detected with antibodies against the surface proteins TAG-1, L1 and DCC. DiI injections show that hippocampal commissural axons do not cross the midline in these mutants. Instead, when axons approach the midline, they turn ventrally and form a massive aberrant projection to the ipsilateral septum. In addition, both the ipsilateral entorhino-hippocampal and the CA3-to-CA1 associational projections show an altered pattern of layer-specific termination in netrin 1-deficient mice. Finally, optical recordings with the Ca(2+) indicator Fura 2-AM show that spontaneous neuronal activity is reduced in the septum of netrin 1-mutant mice. We conclude that netrin 1 is required not only for the formation of crossed connections in the forebrain, but also for the appropriate layer-specific targeting of ipsilateral projections and for the control of normal levels of spontaneous neural activity.

Mouse Tspan-5, a member of the tetraspanin superfamily, is highly expressed in brain cortical structures

Using a subtractive hybridization method for the identification of genes related to the development of the murine cerebral cortex, we cloned a mouse homologue of a human tetraspanin family member, Tspan-5. We have isolated a 3.1 Kb cDNA fragment containing the entire coding region. Analysis of the cDNA nucleotide sequence revealed that mouse Tspan-5 shares 98% amino acid sequence identity with its human homologue. The predicted length of the mouse protein is 268 amino acids, with four putative hydrophobic domains with N- and C-intracellular tails, and two extracellular domains. Northern blot analysis of adult mouse tissues showed a single transcript, which is preferentially expressed in the brain. In situ hybridization showed prominent expression of Tspan-5 in the neocortex, the hippocampus, amygdala and in Purkinje cells in the cerebellum. The pattern of expression of Tspan-5 in the mouse brain suggests a role for the tetraspanins in the maintenance of adult brain function.

[Tolerability and safety of levofloxacinin long-term treatment]

Levofloxacin is a useful quinolone for patients infected with osteomyelitis or tuberculosis. There is little information on the tolerance and safety of levofloxacin in long-term treatment. Fifteen patients (10 men and 5 women) with prosthetic joint infection or chronic osteomyelitis were analyzed. The treatment was levofloxacin (500 mg/d) and rifampicin (600 mg/d). Controls were performed monthly during the treatment, and after that every six months. Problems that were likely related to medication were noted by medical interview. Analyses of hepatic and renal function were performed at each visit. The mean age was 64 years. Ten patients had prosthetic joint infection, two chronic osteomyelitis, two osteosynthetic device infection and one silicone graft infection. Staphylococcus aureus was isolated in eight cases, staphylococcus coagulase being negative in five, and the cultures negative in two cases. The mean duration of treatment was 3.6 months (range 2-6 months). No adverse reactions were observed in seven patients (46%). Occasional digestive symptoms were reported in six patients (40%), and two cases (13%) presented light diarrhea. These patients also took antiinflammatory treatment. Sleeplessness was observed in one patient (6%). Tendinitis or alterations in hepatic function were not observed. In no case was the treatment changed due to adverse reactions. It was concluded that levofloxacin is well tolerated and safe and could be an option for infections that require long-term treatment.

Nerve growth factor but not neurotrophin-3 is synthesized by hippocampal GABAergic neurons that project to the medial septum

Conventional uptake of neurotrophins takes place at axon terminals via specific receptors, and is followed by retrograde transport. Recent studies demonstrated that, with the exception of nerve growth factor, other neurotrophins may be delivered anterogradely to the region containing the receptor expressing neurons. In this study we used a triple labeling method that combines retrograde tract tracing, in situ hybridization and immunocytochemistry to examine whether non-principal cells projecting from the hippocampus to the septum synthesize nerve growth factor. Our results show that, on average, 59% of the horseradish peroxidase-labeled hippocamposeptal nonpyramidal neurons also display nerve growth factor messenger RNA hybridization signal. The ratio was slightly higher in the CA1 stratum oriens and the hilus of the dentate gyrus (64 and 62%, respectively) compared to stratum oriens of the CA3 region (58%). In addition, we demonstrated that many nerve growth factor-positive septally projecting neurons also contain the calcium-binding protein calbindin D-28K, whereas nerve growth factor-negative projecting cells mostly lack this neurochemical marker. In contrast to nerve growth factor, neurotrophin-3 has never been found in hippocamposeptal cells. Hippocamposeptal GABAergic cells are reciprocally connected with the medial septum, thus they are in a key position to regulate nerve growth factor release as a function of the activity level in the septohippocampal system. Furthermore, our results raise the intriguing possibility that nerve growth factor may be transported also in an anterograde manner. Regardless of the direction of transport, the presence of nerve growth factor in hippocamposeptal cells suggests that long distance fast synaptic mechanisms and slow neurotrophin action are coupled in these neurons.

Developmental history of the subplate and developing white matter in the murine neocortex. Neuronal organization and relationship with the main afferent systems at embryonic and perinatal stages

The neuronal diversity of the subplate and developing white matter in the mouse was studied using a variety of neuronal markers. The subplate was first visible in lateral cortical areas at E13, coinciding with the emergence of the cortical plate. During prenatal development, this layer was formed by morphologically heterogeneous neurons, subsets of which were immunoreactive for GABA- and calcium-binding proteins. From E18 onwards, a few subplate cells also contained neuropeptides. Colocalization experiments demonstrated that the percentages of neurons immunoreactive for each antigen were similar to those described in adult neocortex. By E15, subplate cells had received synaptic contacts. Moreover, a second early-neuronal population was conspicuous from E13 in the lower intermediate zone: the intermediate-subventricular population. Unlike subplate cells, these neurons were morphologically uniform, smaller and horizontally oriented. Nevertheless, a few of these cells also appeared within the ventricular zone, with a perpendicular/ oblique orientation. Most of these cells were GABA-positive and showed calbindin immunoreactivity. At the electron microscopic level, no synaptic contacts were found in these neurons. Tracing studies using DiI showed that subplate neurons were the first to send axons outside the neocortex towards the ganglionic eminence at E13. At E14, subplate axons and ingrowing thalamic fibers met in the striate primordium. Subplate cells retained their projection to the thalamus during prenatal development. Thalamocortical axons reached the subplate at E15, and 1 day later began to invade the upper cortical layers. Early callosal axons, in contrast, did not run through the subplate to reach the contralateral hemisphere, nor did subplate cells send out callosal fibers. Callosal axons ran just above the subventricular zone, intermingled with the intermediate-subventricular neuronal population. We conclude that the subplate neuronal population has a chemical heterogeneity reminiscent of that of the adult cortex and is crucial to the establishment of thalamocortical relationships, whereas the intermediate-subventricular neurons constituted a particular GABAergic population, which includes resident cells and tangentially migrating postmitotic neurons spatially related to the development of callosal connections.

[Bacteremia and meningitis caused by Yersinia spp]

Yersinia spp infection in human people are increasing attention last thirty years. We have reviewed the bacteremia in our hospital last five years. Three episodes were Yersinia spp bacteremia. Presence of disease or predisponent therapy were present in most of episodes. All patients were more than seventy years old. The septic metastasis were present in all the cases: one with meningitis, other with liver abscess and one with septic arthritis. We have documented a good clinical evolution, though the mortality in different reports is around 50%. The election therapy for all episodes were cephalosporins, and in two cases we added quinolones.

Disruption of neuronal migration and radial glia in the developing cerebral cortex following ablation of Cajal-Retzius cells

Cortical neurons are generated within the proliferative layer and follow a strict 'inside-out' gradient of migration and positioning, which determines the characteristic layering and pattern of neural connections in the adult cerebral cortex. Thus, directional migration of postmitotic neuroblasts towards layer I and regulation of the radial glia phenotype subserving cortical migration are central issues in corticogenesis. Recent studies showing that the gene disrupted in the reeler mutation--reelin--is expressed in Cajal-Retzius cells have indicated a role for these pioneer neurons in cortical migration. We show here that ablation of Cajal-Retzius cells in layer I by local application of domoic acid in newborn mice arrests migration of the late-generated neurons, destined to cortical layers II-III, that have been labeled by 5-bromodeoxyuridine injections administered at E16. In addition, degeneration of Cajal-Retzius cells in newborn mice dramatically decreases the number of radial glial apical processes identified by nestin-immunostaining, but increases the number of maturing glial fibrillary acidic protein-positive astrocytes. These findings support an essential role for Cajal-Retzius cells in neuronal migration and corticogenesis, by regulating the identity and function of radial glia and the radial glia-to-astrocyte transformation.

Genetic characterization of adenovirus strains isolated from patients with acute conjunctivitis in the city of São Paulo, Brazil

Genome analysis was carried out on adenovirus strains isolated from patients with acute follicular conjunctivitis in the city of São Paulo, Brazil. Eighteen conjunctival scrapings, collected between December 1993 and March 1994, were analyzed by two methods: a combination of polymerase chain reaction with restriction fragment length polymorphism and viral DNA restriction analysis, carried out using 10 restriction endonucleases: BamHI, BglI, BglII, HindIII, KpnI, SacI, SalI, SmaI, XbaI, and XhoI. Among 11 adenovirus detected by cell culture isolation, nine were Ad8, and two were Ad7. By restriction analysis the Ad8 isolates were typed as two new variants-Ad8/D11 (seven of nine samples) and Ad8/D12 (two of nine samples). Ad7 isolates were identified as a subtype of the widespread genome type Ad7b and the virulent type Ad7h, a predominant genome type circulating in Argentina, Chile, and Uruguay but absent in Brazil until 1991.

Netrin 1 acts as an attractive or as a repulsive cue for distinct migrating neurons during the development of the cerebellar system

Netrin 1 is a long-range diffusible factor that exerts chemoattractive or chemorepulsive effects on developing axons growing to or away from the neural midline. Here we used tissue explants to study the action of netrin 1 in the migration of several cerebellar and precerebellar cell progenitors. We show that netrin 1 exerts a strong chemoattractive effect on migrating neurons from the embryonic lower rhombic lip at E12-E14, which give rise to precerebellar nuclei. Netrin 1 promotes the exit of postmitotic migrating neurons from the embryonic lower rhombic lip and upregulates the expression of TAG-1 in these neurons. In addition, in the presence of netrin 1, the migrating neurons are not isolated but are associated with thick fascicles of neurites, typical of the neurophilic way of migration. In contrast, the embryonic upper rhombic lip, which contains tangentially migrating granule cell progenitors, did not respond to netrin 1. Finally, in the postnatal cerebellum, netrin 1 repels both the parallel fibres and migrating granule cells growing out from explants taken from the external germinal layer. The developmental patterns of expression in vivo of netrin 1 and its receptors are consistent with the notion that netrin 1 secreted in the midline acts as chemoattractive cue for precerebellar neurons migrating circumferentially along the extramural stream. Similarly, the pattern of expression in the postnatal cerebellum suggests that netrin 1 could regulate the tangential migration of postmitotic premigratory granule cells. Thus, molecular mechanisms considered as primarily involved in axonal guidance appear also to steer neuronal cell migration.

The early development of thalamocortical and corticothalamic projections in the mouse

The initial ingrowth of corticothalamic and thalamocortical projections was examined in mice at embryonic and perinatal stages. Fibers, in fixed brains, were labeled with the carbocyanine dye 1, 1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocianine perchlorate (DiI). By E13, the corticofugal fibers had entered the lowest intermediate zone through which they ran, turned over the corpus striatum, and left the cortex. The fibers were arranged in scattered bundles throughout the corpus striatum. At E14 corticofugal axons reached the internal capsule and at E14.5-E15 they established contact within the thalamus. Meanwhile, the thalamocortical afferents reached the neocortex at E13. At this time fibers ran tangentially within the intermediate zone, immediately underneath the cortical plate. By E14, the fibers had started to invade the subplate and, by E15, thalamocortical fibers had begun their radial growth into the cortex. Such radial growth proceeded steadily, invading each cortical layer as it differentiated cytoarchitectonically from the dense cortical plate. The first retrogradely labeled cells were detected at the cortical plate at E15. By the day of birth (E20), thalamocortical fibers had formed a dense branching system within layers VI and V. Our observations indicate that, in mice, the thalamic axons reach the cortex before corticothalamic projections enter the thalamic nuclei. Moreover, the results suggest that the pathway followed by each fiber system is different. By DiI injections into the internal capsule we have also determined that subplate cells are the first to send axons to the thalamus.

Pathogenic significance of methicillin resistance for patients with Staphylococcus aureus bacteremia

To assess whether methicillin resistance is a microbial characteristic associated with deleterious clinical outcome, we performed a cohort study on 908 consecutive episodes of Staphylococcus aureus bacteremia and a case-control study involving 163 pairs of patients matched for preexisting comorbidities, prognosis of the underlying disease, length of hospitalization, and age. Of 908 bacteremic episodes, 225 (24.8%) were due to methicillin-resistant S. aureus (MRSA). Multivariate analysis did not reveal that methicillin resistance was an independent predictor for mortality when shock, source of bacteremia, presence of an ultimately or rapidly fatal underlying disease, acquisition of the infection in an intensive care unit (ICU), inappropriate empirical therapy, female sex, and age were taken into account. Nonetheless, methicillin resistance was an independent predictor for shock. The case-control study could not confirm that shock was linked to MRSA when prior antimicrobial therapy, inappropriate treatment, ICU residence, and female sex were considered. Our data suggest that cohort studies tend to magnify the relationship of MRSA with clinical markers of microbial pathogenicity and that this effect is a shortcoming of these kind of studies that is caused by inadequate control for underlying diseases.

Involvement of cajal-retzius neurons in spontaneous correlated activity of embryonic and postnatal layer 1 from wild-type and reeler mice

Cajal-Retzius (CR) cells are a transient population of neurons in developing cortical layer 1 that secrete reelin, a protein necessary for cortical lamination. Combining calcium imaging of cortical hemispheres and cross-correlation analysis, we previously found spontaneous correlated activity among non-CR neurons in postnatal rat layer 1. This correlated activity was blocked by GABAergic and glutamatergic antagonists, and we postulated that it was controlled by CR cells. We now investigate the correlated activity of embryonic and postnatal layer 1 in wild-type and reeler mice, mutant in the production of reelin. We find that mouse layer 1 also sustains patterned spontaneous activity and that CR cells participate in correlated networks. These networks are present in embryonic marginal zone and are blocked by GABAergic and glutamatergic antagonists. Surprisingly, network activity in reeler mice displays similar characteristics and pharmacological profile as in wild-type mice, although small differences are detected. Our results demonstrate that the embryonic marginal zone has correlated spontaneous activity that could serve as the scaffold for the development of intracortical connections. Our data also suggest that reelin does not have a major impact in the development of specific synaptic circuits in layer 1.

[Pneumonia caused by Haemophilus influenzae. Study in a series of 58 patients]

Haemophilus influenzae tends to form part of the usual respiratory flora in adults, especially if they have a chronic underlying disease or are smokers. Pneumonia due to H. influenzae is frequently involved in respiratory infections and its level of resistance to ampicillin has remained stable over the last five years. Most of the literature on the subject was published more than 10 years ago. In this study, we describe the clinical features and evolution of 58 adult patients admitted to hospital for pneumonia due to H. influenzae over a 2-year period, with this group accounting for 6.5% of all the patients admitted with pneumonia during this time period. The etiological diagnosis was made using a good quality sputum sample. Forty patients (69%) were male. The mean age (+/- SD) of the group was 67 (+/-16.8) years and all the patients had at least one underlying disease. The mean duration of the symptoms was 6.7 days. All patients presented an increase in the quantity or purulence of the sputum. On admittance, respiratory failure was present in 52 patients (90%). Gram-negative coccus-bacilli were observed in the direct sputum test and H. influenzae grew in the culture. In two cases, H. influenzae was recovered from the blood culture and in one from bronchial aspiration obtained through bronchoscopy. Another pathogen was identified in 28 patients (48%). In 21 it was another pyogenic bacteria (15 S. pneumoniae, 4 M. catharralis, 1 K. pneumoniae, 1 E. coli), an atypical microorganism in 5 (3 C. pneumoniae, 2 C. burnetii) and a respiratory virus in 2 (syncytial and influenza A). Atypical bacteria and respiratory virus were detected using serological techniques. The radiographic infiltrate was unilobar in 54 of the 58 patients and all showed an alveolar pattern. The empirical treatment included the administration of a third generation cephalosporin (or a fluoroquinolone in patients allergic to penicillin). The evolution was favorable in all the cases in which H. influenzae was the only pathogen or was accompanied by an atypical microorganism or a respiratory virus. Four patients with mixed bacterial pneumonia died (2 S. pneumoniae, 1 E. coli and 1 M. catharralis). The study indicates that pneumoniae due to H. influenzae affects a population with an underlying disease, preferably pulmonary, that it has a longer clinical period than that for pneumococcal pneumonia, that it is slightly bacteremic and, that, usually, it evolves benignly with a low mortality.

Alu-splice cloning of human Intersectin (ITSN), a putative multivalent binding protein expressed in proliferating and differentiating neurons and overexpressed in Down syndrome

By Alu-splice PCR we have trapped two exons and subsequently identified the full length cDNA of a human gene, Intersectin (ITSN), which maps to chromosome 21q22.1 between markers D21S320 and D21S325. The gene has the potential to code for at least two different protein isoforms by alternative splicing (ITSN-L and ITSN-S). Intersectin exists with a high degree of similarity in flies, frogs and mammals, suggesting a conserved role in higher eukaryotes. Analysis of the expression pattern of human and mouse Intersectin detected mRNAs in all adult and foetal tissues tested, with the longer isoform present in brain. In situ hybridisation studies in the developing mouse brain showed ITSN expression in both proliferating and differentiating neurons. The genomic structure of ITSN was determined using the chromosome 21 sequences deposited in the public databases. The protein contains several known motifs which implicate ITSN in clathrin mediated endocytosis and synaptic vesicle recycling. The expression pattern of Intersectin in mouse brain, its presumed function and its overexpression in brains from Down syndrome patients, suggest that Intersectin may contribute in a gene dosage-dependent manner to some of the abnormalities of Down syndrome.

F-spondin and mindin: two structurally and functionally related genes expressed in the hippocampus that promote outgrowth of embryonic hippocampal neurons

Extracellular matrix (ECM) proteins play an important role in early cortical development, specifically in the formation of neural connections and in controlling the cyto-architecture of the central nervous system. F-spondin and Mindin are a family of matrix-attached adhesion molecules that share structural similarities and overlapping domains of expression. Genes for both proteins contain a thrombospondin type I repeat(s) at the C terminus and an FS1-FS2 (spondin) domain. Both the vertebrate F-spondin and the zebrafish mindins are expressed on the embryonic floor plate. In the current study we have cloned the rat homologue of mindin and studied its expression and activity together with F-spondin in the developing rodent brain. The two genes are abundantly expressed in the developing hippocampus. In vitro studies indicate that both F-spondin and Mindin promote adhesion and outgrowth of hippocampal embryonic neurons. We have also demonstrated that the two proteins bind to a putative receptor(s) expressed on both hippocampal and sensory neurons.

Thyroid hormone regulates reelin and dab1 expression during brain development

The reelin and dab1 genes are necessary for appropriate neuronal migration and lamination during brain development. Since these processes are controlled by thyroid hormone, we studied the effect of thyroid hormone deprivation and administration on the expression of reelin and dab1. As shown by Northern analysis, in situ hybridization, and immunohistochemistry studies, hypothyroid rats expressed decreased levels of reelin RNA and protein during the perinatal period [embryonic day 18 (E18) and postnatal day 0 (P0)]. The effect was evident in Cajal-Retzius cells of cortex layer I, as well as in layers V/VI, hippocampus, and granular neurons of the cerebellum. At later ages, however, Reelin was more abundant in the cortex, hippocampus, cerebellum, and olfactory bulb of hypothyroid rats (P5), and no differences were detected at P15. Conversely, Dab1 levels were higher at P0, and lower at P5 in hypothyroid animals. In line with these results, reelin RNA and protein levels were higher in cultured hippocampal slices from P0 control rats compared to those from hypothyroid animals. Significantly, thyroid-dependent regulation of reelin and dab1 was confirmed in vivo and in vitro by hormone treatment of hypothyroid rats and organotypic cultures, respectively. In both cases, thyroid hormone led to an increase in reelin expression. Our data suggest that the effects of thyroid hormone on neuronal migration may be in part mediated through the control of reelin and dab1 expression during brain ontogenesis.

Flow cytometric analysis of metabolic stress effects due to recombinant plasmids and proteins in Escherichia coli production strains

Overexpression of recombinant proteins in Escherichia coli often leads to a severe growth retardation of the host cells. Using flow cytometry, we analyzed the temporal development of the cellular content of DNA, total protein, and the recombinant product (human superoxide dismutase) in different strains. In cells carrying plasmids utilizing the phage T7 promoter 10 (pET vectors), induction with IPTG leads to an increase in protein content and size, an increase and a wide spreading of DNA content distribution, and a termination of cell division. These effects occurred with pET plasmids with or without an insert, but not with another plasmid which utilizes the tac promoter.

Pseudomonas aeruginosa bacteremia in patients infected with human immunodeficiency virus type 1

A prospective analysis of 43 episodes of Pseudomonas aeruginosa bacteremia in HIV-1-infected subjects was performed and the results compared with the incidence and outcome of Pseudomonas aeruginosa bacteremia in other high-risk patients, such as transplant recipients, leukemia patients, or patients hospitalized in the intensive care unit. The incidence of bacteremia/fungemia as a whole and of gram-negative and Pseudomonas aeruginosa bacteremia in particular was greater in HIV-1-infected subjects than in the unselected general population admitted. In contrast, the incidence of Pseudomonas aeruginosa bacteremia in HIV-1-infected patients did not differ from that in patients with other high-risk conditions. In patients with HIV-1 infection, independent risk factors for presenting Pseudomonas aeruginosa bacteremia were nosocomial origin (OR, 2.7; 95% CI, 1.3-5.7), neutropenia (OR, 2.7; 95% CI, 1.07-6.8), previous treatment with cephalosporins (OR, 3.6; 95% CI, 1.1-11.6), and a CD4+ cell count lower than 50 cells/mm3 (OR, 3.1; 95% CI, 1.7-8.6). Primary bacteremia and pneumonia were the most common forms of presentation. Fourteen (33%) patients died as a consequence of the bacteremia. The presence of severe sepsis (OR, 17.5; 95% CI, 3.2-68) and the institution of inappropriate definitive antibiotic therapy (OR, 2.7; 95% CI, 1.1-13) were independently associated with a poor outcome. One year after the development of bacteremia, only eight (19%) patients remained alive.

Expression of neurotrophins in hippocampal interneurons immunoreactive for the neuropeptides somatostatin, neuropeptide-Y, vasoactive intestinal polypeptide and cholecystokinin

Using a double detection method, which combines in situ hybridization for the detection of neurotrophin messenger RNA with immunocytochemistry against the neuropeptides somatostatin, neuropeptide Y, vasoactive intestinal polypeptide and cholecystokinin, we have analysed the expression of the neurotrophins, nerve growth factor, brain-derived neurotrophic factor and neurotrophin-3, in distinct populations of neuropeptide-immunoreactive hippocampal interneurons. Nerve growth factor messenger RNA expression was found in subsets of the four subpopulations of neuropeptide-immunoreactive interneurons. The highest degree of co-localization was observed in the neuropeptide-Y-positive cells (up to 70%) and in somatostatin-immunoreactive cells (48%). Only small subsets of cholecystokinin- and vasoactive intestinal polypeptide-positive neurons (21% and 10%, respectively) displayed nerve growth factor hybridization signals. In contrast, expression of neurotrophin-3 messenger RNA was exclusively observed in 26% of neuropeptide-Y-immunoreactive cells. Brain-derived neurotrophic factor hybridization signals were never detected in the neuropeptide-positive hippocampal interneurons. Morphological analysis of neuropeptide-immunoreactive interneurons that express or lack nerve growth factor messenger RNA revealed that most perisomatic inhibitory neurons, such as large vasoactive intestinal polypeptide/ cholecystokinin-immunoreactive cells, showed positive nerve growth factor hybridization signals. In addition, some somatostatin/neuropeptide-Y-immunoreactive interneurons, which are responsible for dendritic inhibition of principal hippocampal neurons, expressed nerve growth factor messenger RNA. In contrast, interneurons specialized to innervate other GABAergic cells, such as small vasoactive intestinal polypeptide-positive cells, lacked nerve growth factor expression. All these data indicate that expression of neurotrophins is differentially regulated in functionally distinct classes of hippocampal interneurons immunoreactive for neuropeptides. We also analysed whether neuropeptide-immunoreactive interneurons expressing neurotrophins were targets of the GABAergic septohippocampal pathway. We used a triple detection method, combining anterograde tracing of this connection, with in situ hybridization for the detection of neurotrophin mRNA, and immunocytochemistry against neuropeptides. Our data showed that the four populations of hippocampal interneurons studied (somatostatin, neuropeptide-Y, vasoactive intestinal polypeptide and cholescystokinin) received GABAergic afferents from the septum. However, no preference for neuropeptide-immunoreactive cells expressing neurotrophins was observed, compared to neuropeptide-positive neurons lacking neurotrophin expression.

[Predictive factors of the presence of bacteremia in males with urinary infection]

BACKGROUND AND PATIENTS AND METHODS: Possible predictive factors of the presence of bacteremia in 135 males with parenchymatous urinary tract infection (PUI) are studied by means of univariate and multivariate analysis.

RESULTS

Thirty percent of the patients had bacteremia. In the multivariate analysis the following factors were significative: duration of symptoms > 5 days, a serum creatinine level > 1.2 mg/dl and duration of symptoms > 5 days.

CONCLUSIONS

One third of the males with community acquired PUI have bacteremia. The best predictors of the presence of bacteremia are a serum creatinine level > 1.2 mg/dl and duration of symptoms > 5 days.

Development of commissural connections in the hippocampus of reeler mice: evidence of an inhibitory influence of Cajal-Retzius cells

Reelin is a large, extracellular matrix protein involved in neuronal migration and axonal growth. To analyze the contribution of Reelin to the development of the commissural projection in the hippocampus, we analyzed the ontogeny of this projection in the reeler mutant mouse. Injections of the lipophilic tracer DiI revealed many commissural fibers in the hippocampus of both reeler and control mice at P1-P2. At P5, at P12, and in the adult, the topography of commissural connections was normal in the CA1 region of reeler mice, with axons innervating the stratum radiatum and stratum oriens. In contrast, in the CA3/CA2 region, commissural fibers abnormally innervated the stratum lacunosum-moleculare and, in the dentate gyrus, some fibers were observed in the outer molecular layer. Next, we monitored the distribution of Cajal-Retzius cells in the hippocampus of reeler mutant mice and noted that the stratum lacunosum-moleculare of the CA3/CA2 region was largely devoid of Cajal-Retzius (CR) cells. Taken together, the above results indicate that in the absence of CR cells in the CA3/CA2, commissural axons abnormally grow to the stratum lacunosum-moleculare. To test this hypothesis a series of coculture experiments was performed in collagen gels, in which the CA3 axonal growth was monitored when confronted to the marginal zone. These experiments showed that the marginal zone containing CR cells exerts short-range inhibitory influences for commissural axonal growth.

[Disseminated cryptococcosis in patients with AIDS. Prognostic factors of poor outcome]

BACKGROUND

The objectives of this study were to analyze the changes in the incidence of cryptococcal disease in the last 10 years (1987-1997) and to assess the factors of poor prognosis in HIV-1 infected patients.

PATIENTS AND METHODS

Clinical records of HIV-1 infected patients diagnosed with cryptococcal infection from June 1987 to December 1997 at Hospital Clinic i Provincial in Barcelona, Spain, were examined. An univariate and multivariate analysis of the predictors of poor outcome was performed.

RESULTS

Sixty clinical records were analyzed. The number of cases per 100 exposed patients per year decreased from 1991 to 1993 and, afterwards, decreased again from 1996. Fifty patients had a resolution of clinical symptoms, 17 out of this 50 patients (34%) had a relapse. Factors associated with a higher risk of relapse were a positive blood culture and cryptococcal antigen title in cerebrospinal fluid above 1/1.024.

CONCLUSIONS

The decrease in the number of cases of cryptococcal infection coincides with the broad use of triazole antifungal drugs for oral candidiasis (1990-1991) and, afterwards, with the initiation of highly active antiretroviral therapy (1996). The best predictors of relapse are a positive blood cryptococcal culture and a high titter of cryptococcal antigen.