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Biomedical subjects

F Esposito

Publications and source records attributed to F Esposito.

At least 145 records · Page 8Linked to original sources
PubMed1976

Cell surface control in Blepharisma intermedium (Protozoa Ciliata). Blocking of gamone II-induced homotypic interacting ligands.

PHA, Con-A, or anti-tubulin antibodies inhibit homotypic pair formation, in B, intermedium mating type-I cells in the presence of suboptimal concentrations of gamone II. The inhibition is dependent on the dose of gamone added; the structural conformation and the relative concentration of the inhibitor; and the time of addition of the inhibitor. The block can be selectively prevented by competitive inhibitors of each ligand. The receptors for the inhibitors are distinctive and there is no cross-reaction between the ligands. It is concluded that ligand binding and subsequent receptor-ligand aggregation must induce a change within the cell-surface membrane, which distorts the distribution and/or affects an optimal conformational aspect of a specific membrane-receptor system for the gamon, a prerequisite for cell pair formation.

Acetylgalactosamine↗
PubMed1975

Conjugation in Oxytricha bifaria: cell interaction.

As a model of cell interaction, the mating process of Oxytricha bifaria has been investigated. Mating involves several distinct and sterotyped stages, each lasting a determined time, and ending with the formation of firmly united pairs. A "waiting period" intervenes between the mixture of complimentary mating types and the onset of cell interaction. A proper starvation shortens the waiting period (25 min vs 120 min). Treatment of properly starved cells with heterologous cell-free fluid further reduces the waiting period. Certain enzyme treatments (pronase, trypsin and lipase) dramatically increase the waiting period in both washed enzyme-treated cells and in unwashed cells. Trypsin inhibits the first two stages of the mating process, while lipase inhibits membrane fusion between mates.

Cell Division↗
PubMedDate not supplied

Transabdominal sonography of the normal gastroesophageal junction in children.

PURPOSE: Because sonography identifies abnormalities of the gastroesophageal junction, it is essential to understand the normal sonographic anatomy. The aim of this study was to determine the normal sonographic appearance of the gastroesophageal junction and its variations and to provide measurements of the abdominal esophagus in asymptomatic, healthy children. METHODS: In this prospective study, 124 healthy children (75 boys and 49 girls), aged 2 days-12 years, underwent abdominal sonography. With the patient in a supine position, the transducer was placed under the xiphoid and the ultrasound beam was directed cephalad through the window of the left lobe of the liver. The length of the abdominal esophagus was measured from the point at which it penetrated the diaphragm to the gastroesophageal junction. The thickness was measured on the anterior wall at the midpoint of the abdominal esophagus. RESULTS: The gastroesophageal junction was identified by sonography in all of the children. The mean length of the abdominal portion of the esophagus ranged from 18 mm in the newborns to 34 mm in children older than 6 years. The wall thickness ranged from 2.4 mm to 5.7 mm. CONCLUSIONS: Our results indicate that visualization of the gastroesophageal junction and measurement of the abdominal esophagus are readily achievable with real-time sonography in healthy children.

Abdomen↗
PubMedDate not supplied

Disseminated mycobacterial infection in AIDS patients: abdominal US features and value of fine-needle aspiration biopsy of lymph nodes and spleen.

BACKGROUND: We evaluated the efficacy of abdominal ultrasound (US) and fine-needle aspiration biopsy (FNAB) in the diagnosis of disseminated mycobacteriosis (DM) in acquired immunodeficiency syndrome (AIDS). METHODS: Twelve AIDS patients (nine male, three female; age range, 22-43 years) with DM underwent abdominal US within 2 days after admission with 3.5- to 5-MHz convex probes and a 7.5-MHz linear probe. All patients underwent FNAB of one or two enlarged abdominal lymph nodes. Eight patients underwent FNAB of the spleen. The aspirated specimens were stained with acid fast for quick examination and cultured for isolation of mycobacteria. RESULTS: Abdominal US showed enlarged, hypoechoic, round or oval, abdominal lymph nodes (diameter, 10-35 mm; mean, 18 mm) in all patients; splenomegaly (spleen diameter, 14-22 cm; mean, 16.8 mm) in all patients; numerous splenic abscesses (diameter, 3-20 mm) in nine patients; hepatomegaly (right hepatic lobe thickness, 14.5-17 cm) in all patients; small intestinal wall thickening in five patients (maximum bowel wall thickness, 7-15 mm); mild to moderate ascites in six patients; pleural effusion in four patients; bilateral enlargement of the kidneys with hyperechogenicity of the cortex in three patients; and a retroperitoneal tubercular abscess in one patient. No complication occurred after FNAB of lymph nodes and spleens. Fast-acid stain of spleen and/or lymph node FNAB specimens allowed early diagnosis of mycobacteriosis in 12 of 12 cases (100%). Cultures of lymph node aspirates grew mycobacteria in six of 12 patients (50%). Spleen aspirates grew mycobacteria in nine of nine patients (100%). Blood cultures were positive in four of 12 patients (33%). Mycobacterium tuberculosis was diagnosed in six patients and M. avium in five. CONCLUSION: Abdominal US features can suggest DM in AIDS patients. Spleen and/or lymph node FNAB indicated the specific diagnosis in 100% of patients.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

Diagnosis of benign and malignant portal vein thrombosis in cirrhotic patients with hepatocellular carcinoma: color Doppler US, contrast-enhanced US, and fine-needle biopsy.

BACKGROUND: We assessed the role of contrast-enhanced ultrasound (CEUS) in the differential diagnosis between benign and malignant portal vein thrombosis in patients who had cirrhosis with hepatocellular carcinoma (HCC). METHODS: Fifty-four consecutive patients who had cirrhosis, biopsy-proved HCC, and thrombosis of the main portal vein and/or left/right portal vein on US were prospectively studied with color Doppler US (CDUS) and CEUS. CEUS was performed at low mechanical index after intravenous administration of a second-generation contrast agent (SonoVue, Bracco, Milan, Italy). Presence or absence of CDUS signals or thrombus enhancement on CEUS were considered diagnostic for malignant or benign portal vein thrombosis. Twenty-eight patients also underwent percutaneous portal vein fine-needle biopsy (FNB) under US guidance. All patients were followed-up bimonthly by CDUS. Shrinkage of the thrombus and/or recanalization of the vessels on CDUS during follow-up were considered definitive evidence of the benign nature of the thrombosis, whereas enlargement of the thrombus, disruption of the vessel wall, and parenchymal infiltration over follow-up were considered consistent with malignancy. CDUS, CEUS, and FNB results were compared with those at follow-up. RESULTS: Follow-up (4 to 21 months) showed signs of malignant thrombosis in 34 of 54 patients. FNB produced a true-positive result for malignancy in 19 of 25 patients, a false-negative result in six of 25 patients, and a true-negative result in three of three patients. CDUS was positive in seven of 54 patients. CEUS showed enhancement of the thrombus in 30 of 54 patients. No false-positive result was observed at CDUS, CEUS, and FNB. Sensitivities of CDUS, CEUS, and FNB in detecting malignant thrombi were 20%, 88%, and 76% respectively. Three patients showed negative CDUS and CEUS and positive FNB results; follow-up confirmed malignant thrombosis in these patients. One patient showed negative CDUS, CEUS, and FNB findings. However, follow-up of the thrombus showed US signs of malignancy. Another FNB confirmed HCC infiltration of the portal vein. CONCLUSION: CEUS seems to be the most sensitive and specific test for diagnosing malignant portal vein thrombosis in patients with cirrhosis.

Aged↗
PubMedDate not supplied

Detecting malaria sporozoites in live, field-collected mosquitoes.

A method is described for identifying malaria-infected mosquitoes, without killing them or hampering their fitness. Individual mosquitoes were induced to salivate on coverslips, and sporozoites, deposited on the glass surface, were visualized by Giemsa staining. Of 21 mosquitoes found to contain sporozoites by salivary gland dissection, 13 had delivered sporozoites on coverslips. A positive correlation was found between the amount of saliva expelled and ejection of sporozoites, indicating that the sensitivity of the method may be increased by improving the probing behaviour of the mosquitoes. The procedure described may be suitable for selecting infected mosquitoes which are able to eject sporozoites during probing. Being applicable to wild Anopheles and to large numbers of mosquitoes, the method lends itself for use in field studies on malaria.

Animals↗
PubMedDate not supplied

Insecticide-treated materials, mosquito adaptation and mass effect: entomological observations after five years of vector control in Burkina Faso.

Insecticide-treated bednets and curtains have been shown to be successful in reducing malaria transmission and child mortality in Africa over periods of up to 2 years. A major concern relating to this approach is that, in time, it will be compromised by the selection of mosquito genotypes that are resistant at the biochemical or behavioural level. We report entomological data from a large area in Burkina Faso where insecticide-treated curtains have been in use for up to 5 years. Longitudinal indoor and outdoor CDC light-trap catches were performed in 4 sentinel villages. In addition cross-sectional surveys using indoor spray catches and outdoor CDC light-trap catches were performed each September in a larger number of villages, including 8 located outside the intervention area. We found no evidence of the selection of mosquito phenotypes that might compromise the intervention. Indoor and outdoor vector densities remained very low after 5 years of intervention, both compared with pre-intervention levels and with concurrent levels outside the intervention area. We found no evidence of a switch to outdoor rather than indoor biting. The proportion of blood meals taken on humans may have decreased but our data are inconclusive on this point. We observed higher vector densities and sporozoite rates at the periphery of the intervention zone than at the centre, which may reflect re-invasion of peripheral villages by mosquitoes from outside the intervention area. In 'real life' programmes, with perhaps patchy, less than optimal coverage, the protection against malaria transmission provided to individuals using insecticide-treated materials may be less than that achieved in the randomized controlled trials which demonstrated an impact of insecticide-treated materials on child mortality.

Animals↗
PubMedDate not supplied

Comparison of two methods for assessing child mortality in areas without comprehensive registration systems.

We compared the effectiveness of 2 approaches to assessing child deaths in a rural area of Burkina Faso, West Africa. Censuses, repeated yearly, identified 410 child deaths in the age range 6-59 months. Surveillance using community informants identified only 319 deaths. The estimated sensitivities of the 2 systems were 97% and 76%, respectively. Both systems appeared less effective at detecting child deaths before 6 months of age (sensitivities 74% and 57%). Most of the deaths missed by the census were of children born since the previous census. The cost of one year's surveillance was twice that of a single census. The marginal cost of the surveillance system per additional child death identified between 6 and 59 months was about US$ 1500. Thorough annual censuses may be sufficient to ascertain almost all child deaths over 6 months of age. In studies wishing to identify child deaths before 6 months of age, such an approach is unlikely to be adequate. In such situations, our data indicated that the use of unpaid community informants can improve assessment of deaths. Where accurate assessment of early infant death rate is required, regular visits to each household by members of the study team are likely to be the only reliable approach.

Birth Rate↗
PubMedDate not supplied

A community-based programme to provide prompt and adequate treatment of presumptive malaria in children.

A community-based programme to ensure prompt and adequate treatment of presumptive episodes of clinical malaria in children has been established in a rural province of Burkina Faso. The implementation strategy was based on training a core group of mothers in every village and supplying community health workers with essential antimalarial drugs specially packed in age-specific bags containing a full course of treatment. Drugs were sold under a cost-recovery scheme. The programme was run in 1994 by the national malaria control centre (CNLP), and in 1995 it was developed to the provincial health team (PHT). Knowledge and awareness of malaria increased with the intervention. Drug consumption by age group was compatible with the distribution of disease, and no major problem of misuse emerged. The actual implementation costs of the intervention were US$ 0.06 per child living in the province. An evaluation of the impact of the intervention on the severity of malaria, using routine data from the health information system and taking as an indicator the proportion of malaria cases which were recorded as severe in health centres, was performed. In 1994, when the intervention was implemented on a provincial scale by CNLP, this proportion was lower than the average of the 4 preceding years (3.7% vs. 4.9%). In 1995, when the programme was implemented by the PHT, the proportion of severe cases was lower in health centres achieving a programme coverage of > or = 50% in their catchment area compared with the others (4.2% vs. 6.1%). Our experience shows that a low-cost, community-based intervention aimed at providing children with prompt and adequate treatment of presumptive episodes of clinical malaria is feasible, and suggests that it may lead to a reduction in the morbidity from severe malaria.

Acetaminophen↗
PubMedDate not supplied

Wide-scale installation of insecticide-treated curtains confers high levels of protection against malaria transmission in a hyperendemic area of Burkina Faso.

In a region of Sudanese savannah in Burkina Faso, insecticide-treated curtains were installed in 8 out of 16 zones, each covering an area of about 50 km2. Longitudinal entomological monitoring using CDC light traps was performed in 4 villages (2 intervention, 2 control) over a period of 3 years (including 1 year prior to intervention). In the 3rd year a cross-sectional entomological survey using spray catches was performed in 84 villages (40 intervention). Indoor vector densities in protected houses showed large reductions (P = 0.01). The available data were also consistent with an impact on outdoor and unprotected indoor densities. The proportion of mosquitoes carrying sporozoites was 4.1% in protected villages compared with 11.5% in unprotected villages (P = 0.07). Entomological inoculation rates fell substantially (P = 0.01), reflecting these reductions. The impact of this intervention on mosquito survival appears to have been greater than those in similar trials conducted in the Gambia, Ghana and Kenya in which the intervention was applied over smaller areas.

Animals↗
PubMedDate not supplied

Gene expression and morphological changes in surgically injured carotids of spontaneously hypertensive rats.

The expression profiles of genes involved in cell proliferation, differentiation and programmed death were investigated in carotids of spontaneously hypertensive rats (SHR) treated with a model of surgical injury that mimics events occurring during arterial grafts, endarterectomy and organ transplantation. The mRNA level of the c-myc, angiotensin II receptor 1 (AT1), Rb/p105, Rb2/p130, Bcl-2 and Bax-alpha genes was assessed by a semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) technique at different times up to 48 h after injury, while the morphological changes were evaluated 30 days after injury. The proliferation marker c-myc increases almost immediately, peaks after 4 h and returns to basal levels after 24 h; the AT1 receptor mRNA reaches its maximal level 48 h after injury. The level of cell cycle exit markers Rb/p105 and Rb2/p130 gradually decreases after injury. The apoptosis marker Bcl-2/Bax-alpha ratio shows a significant reduction only 4 h after injury, resuming the initial value after 24 and 48 h. Morphological analysis reveals that surgical injury in SHR induces adventitial and medial constrictive remodeling changes rather than intima proliferation as in balloon angioplasty. Both molecular and histological data show substantial differences with respect to normotensive rats.

Animals↗
PubMedDate not supplied

Mechanisms of regulation of the capillary bed in the human chorionic villi.

The purpose of the present researches was to confirm the hypothesis that in the human placenta the microcirculation is subjected to humoral control, because of the absence of innervation in the chorionic villi and the ability of the capillaries to contract themselves. Chorionic villi were incubated in presence of vasoactive substances, Histamine, Serotonin, Bradykinin, Dopamine, Enkephalin Prostaglandins. After incubation, the specimens were fixed and embedded in resin. Semithin sections were submitted to a computerized analysis for the evaluation of the ratio between surface of capillaries and surface of the villus. The results confirmed that in the control of capillaries in the human placenta most of the tested substances show a specific action, dose- or time-dependent.

Capillaries↗
PubMedDate not supplied

Immunity to Plasmodium sporozoites: recent advances and applications to field research.

The presence of antibodies against Plasmodium falciparum sporozoites in humans living in malaria endemic areas was measured using as antigen the synthetic peptide (NANP)3, which represents the immunodominant region of the circumsporozoite (CS) protein. The results indicate that: i) the production of anti-CS antibodies is unrelated to the presence in the circulation of blood-stage parasites; ii) anti-CS antibodies, raised by natural inoculation, could exert a protective role against natural malaria infection; iii) anti-CS antibodies can be used as indicators of the intensity of malaria transmission.

Age Factors↗