Preventing perinatal transmission of HIV-1 infection

It is now known that with the use of antiretroviral prophylaxis with zidovudine, elective caesarean section delivery and refraining from breastfeeding the rate of mother-child transmission of HIV infection can be reduced to less than 2%.     

Non-Hodgkin's lymphoma in childhood presenting as thyroid enlargement

The authors report a case of a 10-year-old girl with early involvement of the thyroid gland by non-Hodgkin's lymphoma, an uncommon site of presentation of childhood lymphomas. In pediatrics, thyroid enlargement is more often caused by lymphocytic thyroiditis. The good response to therapy, in spite of the advanced stage of the disease, is noted.     

Concomitant effect of topical ubiquinone Q10 and vitamin E to prevent keratocyte apoptosis after excimer laser photoablation in rabbits

PURPOSE: To investigate in vivo whether ubiquinone Q10 together with vitamin E protects rabbit corneas from keratocyte apoptosis after excimer laser irradiation. METHODS: Photorefractive keratectomy (PRK) was performed in both eyes of three New Zealand white rabbits. During 3 days before surgery, each right eye received four-times-daily instillation of an eye-drop solution containing ubiquinone Q10 0.20% and vitamin E 0.04%; each left eye was treated with a solution that did not contain ubiquinone or vitamin E. The central cornea was analyzed after surgery using the in situ end labelling (ISEL) technique of nicked DNA to detect DNA fragmentation. To determine the number of ISEL positive nuclei, an average of 70 random microscopic fields (five for each de-epithelialized tissue section) of 138,000 mu2 were examined in the right and left cornea samples at 250X by two different observers. RESULTS: Light microscopic examination of the sections from corneas treated before PRK showed that cells committed to apoptosis by PRK were about 50% compared to those of untreated controls. CONCLUSION: Treatment of rabbit eyes before PRK with ubiquinone Q10 lowered the number of apoptotic events.     

Fractionated analysis of paired-electrode nerve recordings

Multi-unit activity recorded from two electrodes positioned at a distance on a nerve may be analysed by cross-correlation, but units similar in direction and velocity of propagation cannot be distinguished and separately evaluated by this method. To overcome this limit, we added two features, represented by the impulse amplitudes of the paired recordings, to the dimension given by the impulse delay. The analysis was fractionated according to the new dimensions. In experimental recordings from the locomotor appendage of the lobster Homarus americanus, the fractionated analysis proved capable of identifying the contributions of single active units, even if these were superimposed and indiscernible in the global cross-correlation histogram. Up to 5 motor and 10 sensory units could be identified. The shape of the paired impulses was evaluated by an averaging procedure. Analogous evaluations on simulated recordings made it possible to estimate the influences exerted on performance by variations in noise level and in the number and firing rate of active units. The global signal could be resolved into single units even under the worst conditions. Accuracy in evaluating the amount of unit activity varied, exceeding 90% in about half of the cases tested; a similar performance was attained by evaluation of the impulse shapes.     

Brain function in the vegetative state

Positron emission tomography (PET) techniques represent a useful tool to better understand the residual brain function in vegetative state patients. It has been shown that overall cerebral metabolic rates for glucose are massively reduced in this condition. However, the recovery of consciousness from vegetative state is not always associated with substantial changes in global metabolism. This finding led us to hypothesize that some vegetative patients are unconscious not just because of a global loss of neuronal function, but rather due to an altered activity in some critical brain regions and to the abolished functional connections between them. We used voxel-based Statistical Parametric Mapping (SPM) approaches to characterize the functional neuroanatomy of the vegetative state. The most dysfunctional brain regions were bilateral frontal and parieto-temporal associative cortices. Despite the metabolic impairment, external stimulation still induced a significant neuronal activation (i.e., change in blood flow) in vegetative patients as shown by both auditory click stimuli and noxious somatosensory stimuli. However, this activation was limited to primary cortices and dissociated from higher-order associative cortices, thought to be necessary for conscious perception. Finally, we demonstrated that vegetative patients have impaired functional connections between distant cortical areas and between the thalami and the cortex and, more importantly, that recovery of consciousness is paralleled by a restoration of this cortico-thalamo-cortical interaction.     

Aortic suspension (aortopexy) for severe tracheomalacia in infants and children

BACKGROUND: Tracheomalacia with anterior great vessel compression is a common disorder in infants and children, which can lead to life-threatening airway occlusion. In this study, a large number of patients underwent anterior aortopexy to provide a more normal distal airway. METHODS: Thirty-two infants and children with tracheomalacia associated with esophageal atresia-tracheoesophageal fistula (18), vascular ring (8), abnormal innominate artery takeoff (4), and primary (2) were evaluated with bronchoscopy, magnetic resonance imaging, and pulmonary functions. Aortopexy was accomplished through left thoracotomy and suture fixation of the aorta and innominate artery to the posterior sternum. RESULTS: Intraoperative bronchoscopy showed marked improvement in airway caliber and rigidity, and no patients had further obstructive episodes. Forced expiratory volume improved from 52% +/- 4% of predicted to 82% +/- 3%. CONCLUSIONS: Aortopexy is a simple procedure for the treatment of distal tracheomalacia that is immediately effective and provides permanent relief of obstructive episodes.     

Sternal wound infection revisited

Sternal wound infections (SWIs) can be subdivided into two types, superficial or deep, that require different treatments. The clinical diagnosis of superficial SWI is normally easy to perform, whereas the involvement of deep tissues is frequently difficult to detect. Therefore, there is a need for an imaging study that permits the assessment of SWIs and is able to distinguish between superficial and deep SWI. The present work was a prospective study aiming to evaluate the role of technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) labelled leucocyte scan in SWI management. Twenty-eight patients with suspected SWIs were included in the study. On the basis of clinical examination they were subdivided into three groups: patients with signs of superficial SWI (group 1), patients with signs of superficial SWI and suspected deep infection (group 2) and patients with suspected deep SWI without superficial involvement (group 3). Ten patients previously submitted to median sternotomy, but without suspected SWI, were also included in the study as a control group (group 4). All patients with suspected SWI had bacteriological examinations of wound secretion, if present. In addition 99mTc-HMPAO labelled leucocyte scan was performed in all patients. The patients of groups 1, 2 and 3 were treated on the basis of the clinical signs and microbiological findings, independently of the scintigraphic results. The patients of group 4 did not receive treatment. The final assessment of infection was based on histological and microbiological findings or on long-term clinical follow-up. Sensitivity, specificity, accuracy and positive and negative predictive values for scintigraphic and non-scintigraphic results were calculated. In the diagnosis of superficial and deep SWI, clinical and microbiological examination (combined) yielded, respectively, a sensitivity of 68.7% and 100%, a specificity of 77.3% and 80.8%, an accuracy of 73.7% and 86.8%, a positive predictive value of 68.7% and 70.6% and a negative predictive value of 77.3% and 100%. The scintigraphic results obtained in superficial SWI yielded a sensitivity of 56.2%, a specificity of 90.9%, an accuracy of 76.3%, a positive predictive value of 81.8% and a negative predictive value of 74.1%, while, by contrast, in deep SWI all of these values were 100%. Therefore, one can conclude that 99mTc-HMPAO labelled leucocyte scan permits accurate diagnosis of deep SWI, solving the main clinical problem in this field. In the present study the categorisation of patients without taking into account 99mTc-HMPAO labelled leucocyte planar scan findings caused a non-negligible number of cases of superficial SWI to be treated as though they were deep SWI. This "overestimation" led to unnecessary surgery, increased and prolonged use of antibiotics with more (higher) toxicity and additional expense.     

Enterovirus surveillance of Italian healthy children

Surveillance of acute flaccid paralysis (AFP) is the golden strategy recommended by the WHO to verify the condition of polio eradication in a country. Because of the difficulty to detect all of the expected AFP cases and to reach the target incidence of 1/100,000 requested by WHO, the surveillance of enteroviruses in the population has been adopted by several countries as an important additional method to verify the absence of wild-poliovirus circulation. To complete the results of AFP surveillance set up in Italy in 1996, we have conducted a wild poliovirus surveillance by examining stool samples from 1551 healthy children aged less than 5 years, collected during the period January 1997 to January 1998. The children were from three cities (Parma, Rome and Bari) located in northern, central and southern Italy. Thirty-nine polioviruses, 72 non-polio enteroviruses and 50 enteric, non-entero (NE), viruses were isolated from stool specimens. Polioviruses identified were nine type 1, seven type 2 and twenty-three type 3. Characterization of isolates by both antigenic and molecular methods showed that all polioviruses were of vaccine origin. As expected, most polioviruses, especially types 2 and 3, presented retromutations known to be associated with loss of the Sabin attenuated phenotype. The results of this study support the data obtained from the active AFP surveillance conducted in Italy in the same period – on the absence of paralytic disease due to wild poliovirus – and altogether demonstrate the effectiveness of the vaccination program.