Gabriella Serio

A generalization of the Kermack-McKendrick deterministic epidemic model☆

Abstract In this paper the Kermack-McKendrick deterministic model is generalized, introducing an interaction term in which the dependence upon the number of infectives occurs via a nonlinear bounded function which may take into account saturation phenomena for large numbers of infectives. An extension of the well-known threshold theorem is obtained, after a stability analysis of the equilibrium points of the system. A numerical example is carried out in detail.

Premature lesions of the carotid vessels in HIV-1-infected patients treated with protease inhibitors.

ObjectivesTo evaluate the presence of premature atherosclerotic lesions of epiaortic vessels in HIV-1-infected protease inhibitor-(PI) treated patients compared with PI-naive patients and healthy individuals. DesignOne-hundred and two HIV-1-positive patients, including 55 treated with PI for at least 12 months and 47 either naive or treated with PI-sparing regimens, were subjected to epiaortic vessel ultrasonography. These data were compared with those obtained from 104 healthy individuals. MethodsIntima characteristics, pulsation and resistance indexes, and minimal, peak and mean speed were evaluated using a colour power doppler. Atherosclerotic plaques were described. Independent risk factors and values for glycaemia, cholesterolaemia and triglyceridaemia were considered. Statistical analysis included the chi-square test, Mantel–Haenszel test, odds ratio and logistic regression analysis. ResultsOf the PI-treated patients, 29 out of 55 (52.7%) presented acquired lesions of the vascular wall at ultrasonography, whereas similar lesions were found in seven out of 47 (14.9%) PI-naive patients. Of the 104 healthy individuals, seven cases (6.7%) of intimal medial thickness were noted. A slightly significant correlation was found between carotid lesions and age, male sex and hypercholesterolaemia, whereas cigarette smoking, hypertriglyceridaemia and Centers for Disease Control and Prevention stage significantly increased the risk of vascular lesions (P = 0.022, P = 0.017 and P = 0.079 respectively). However, the highest significance regarded use of PI (P = 0.011). These results were confirmed by logistic regression analysis. ConclusionsThese data demonstrate a higher than expected prevalence of premature carotid lesions in the PI-treated compared with PI-naive patients. If confirmed, a periodic ultrasonographic study of the vascular wall should be included in the follow-up of HIV infected patients.

PCNA and Ki67 expression in breast carcinoma: correlations with clinical and biological variables.

AIMS: To investigate the expression of two cell cycle related antigens (proliferating cell nuclear antigen (PCNA) and Ki67 related antigen) in a series of breast cancers; and the possible correlations between the PCNA and Ki67 labelling indexes (PCNA-LI and Ki67-LI) and their associations with other biological and clinicopathological variables. METHODS: Ninety six ductal and 10 lobular carcinoma specimens were investigated. Samples were fixed in formalin and in Methacarnoy for localisation of PCNA. Ki67 was immunostained on frozen sections. The PCNA-LI and Ki67-LI were evaluated in relation to tumour size, mitotic count, histological grade, nodal state as well as receptor content and altered expression of the p53 gene. RESULTS: PCNA-LI did not correlate with Ki67-LI, nor was it associated with any other variable examined. A high KI67-LI (above the median value of 13.5) was associated with high grade and mitotic count, negative receptor content, and altered expression of the p53 gene, but not with other variables. CONCLUSIONS: The PCNA-LI does not seem to be a substitute for the Ki67-LI in evaluating the growth fraction in breast cancer.

Effect of Antiretroviral Therapy on Cryptosporidiosis and Microsporidiosis in Patients Infected with Human Immunodeficiency Virus Type 1

Abstract To better understand whether potent antiretroviral therapies can modify the natural history of HIV-1-associated microsporidiosis and cryptosporidiosis, the response to antimicrobial treatment of these opportunistic infections was evaluated in patients with or without antiretroviral treatment. Fifty patients with diarrhoea, all positive for Cryptosporidium parvum or Enterocytozoon bieneusi, were included in the study. Retrospective data were collected concerning demographics, clinical and microbiological characteristics of the parasitic infection, antiretroviral therapy and prophylaxis against opportunistic infections. Faecal samples were prepared using the Richie formalin-ethyl acetate method and stained using the modified Ziehl-Neelsen method for detection of Cryptosporidium parvum and Isospora belli, the modified trichrome and calcofluor white technique for detection of Enterocytozoon spp., and iodine for detection of ova, cysts or vegetative forms. Diarrhoea was defined as an abnormal increase in stool liquidity, an abnormal increase in stool frequency and a daily stool weight of more than 250 g for a period of at least 4 days. Patients treated with double antiretroviral therapy or protease inhibitors demonstrated an excellent response and a sustained therapeutic effect after follow-up (range, 5–36 months). The relapse of cryptosporidiosis in two patients who discontinued antiretroviral therapy suggests that the infection might remain in a latent stage. The resolution of the diarrhoea seems to be related to an increased CD4+ cell count rather than to the viral load. In conclusion, these data strongly support the hypothesis that combination antiretroviral therapy is able to greatly modify the course of cryptosporidiosis and microsporidiosis in patients infected with HIV-1.

Sex chromosome loss, micronuclei, sister chromatid exchange and aging: a study including 16 centenarians

In the present study we analysed the possible effect of age, sex and smoking on the mean values of micronucleus (MN) and sister chromatid exchange (SCE) frequencies on peripheral blood obtained from 38 subjects ranging in age from 16 to 63 years and 16 centenarians. The mean number of binucleated cells with micronuclei varied in function of age and sex (as demonstrated by the analysis of covariance (F=13.13; P<0.001), particularly evident was the increment observed in women with increasing age (interaction age/sex: F=5.53; P<0.05). Smoking habits had no effects on MN frequency (F=0.36; P>0.05). Sex (F=4.18; P<0.05) and smoking habits (F=14.64; P<0.001) influenced significantly SCE per cell frequencies, but age had no effects on them (F=2.45; P>0.05). The age-associated increase of sex chromosome loss was studied using fluorescence in situ hybridisation (FISH) on interphase nuclei. The loss of Y signals was observed in approximately 10% of interphase cells from the centenarians males, that is six times more often than in the younger control men (approximately 1.6%). The frequency of X signal loss (approximately 1.7%) in young women was similar to that observed in male controls of the same age but the incidence of the X chromosome aneuploidy in centenarian females was appreciably higher (approximately 22%) than that found for the Y chromosome in males. These results were correlated with the data on MN formation and a positive correlation between the percentage of aneuploid cells (FISH) and MN values was observed (r=0.50; P<0.05).

Increased risk of lymphoproliferative disorders in relatives of patients with B-cell chronic lymphocytic leukemia: relevance of the degree of familial linkage.

Abstract: We assessed the familial aggregation of chronic lymphoproliferative diseases (CLD) in 3962 relatives of 169 patients with B‐cell chronic lymphocytic leukemia (B‐CLL). Data collection included a self‐administered questionnaire. The “relative risk” considered the connection between a higher incidence of CLD and the degree of familial linkage with the probands. The model of logistic regression was statistically significant (p<0.001), with the probability of CLD increasing in proportion to the relationship coefficient between parents, siblings and children [(relationship coefficient 0.5; probability of CLD 1.85 (C.I. 95%, range 1.1–3%)]. CLD, particularly B‐CLL, were observed in first‐degree relatives of the patients with B‐CLL more often than in other relatives.

Fetal blood-brain barrier P-glycoprotein contributes to brain protection during human development.

During brain development and blood-brain barrier (BBB) differentiation the expression of P-glycoprotein (P-gp) may complement the protective function of the placental barrier against xenobiotic substances. To establish an immunohistochemical procedure for P-gp detection, different anti-P-gp monoclonal antibodies were first tested on a fibrosarcoma cell line and colonic carcinoma tissue. The protocol was then tested on adult human brains as a BBB-P-gp tissue-specific control and for double labeling with anti-P-gp and the astroglia marker glial fibrillary acidic protein (GFAP). The protocol was then used to analyze the expression and localization of P-gp in human fetuses during cerebral cortex formation. At the earliest examined stage, 12 weeks of gestation (wg), P-gp was detectable as diffuse cytoplasmic labeling of the endothelial cells lining the primary cortex microvessels. At 18 wg, a punctate P-gp staining pattern was detected on cortex and subcortical vessels and on their side branches. At 22 wg, P-gp staining was linear and concentrated on endothelial cell membranes. In all examined ages, GFAP-positive radial glial cells and astrocytes did not stain for P-gp, even at their perivascular processes, whereas faint P-gp labeling was seen on vimentin-reactive radial glia at the earliest examined fetal age. At midgestation, P-gp colocalized with caveolin-pY14 on the abluminal endothelial cell membrane. These results demonstrate that P-gp is expressed early during human cerebral cortical microvessel development, and suggest that at midgestation there may be efflux activity that is regulated by interactions with the caveolar endothelial cell compartment.

Occurrence of portal vein tumor thrombus in hepatocellular carcinoma affects prognosis and survival. A retrospective clinical study of 150 cases

Hepatocellular carcinoma (HCC) is one of the most common malignancies in the world. Despite improvements in diagnostic and therapeutic interventions, prognosis and survival are still poor. To identify factors influencing survival, we retrospectively examined 150 consecutive patients with HCC from the time of first diagnosis of cirrhosis to death. In a multivariate analysis, we found that patients with larger HCC lesions had shorter survival, while other pathologic features had no predictive value. The most important and reliable prognostic factor was the occurrence of tumor thrombus of the portal vein (P<0.01). Childs stage of underlying liver disease was relevant only in the univariate, but not in the multivariate analysis. The survival of patients with HCC is mainly affected by the biological ability of cancer cells to invade surrounding tissue and vessels. More studies are needed to elucidate the mechanisms that modulate tumor cell motility, in order to design more effective therapies.

Malignant deciduoid mesothelioma of the pleura: report of two cases with long survival.

Malignant deciduoid mesothelioma of the pleura: report of two cases with long survival

A cluster of familial malignant mesothelioma with del(9p) as the sole chromosomal anomaly

We describe a family of three sisters affected by malignant mesothelioma (MM) (2 pleural and 1 peritoneal) and one brother affected by pleural plaques. All members of the family had been subjected to previous asbestos exposure of environmental-residential type. For 13 years, from 1951 to 1964, their housing was provided by the fathers employer, an asbestos cement factory, and the factory warehouse was on the ground floor of the building they lived in. DNA extracted from paraffin-embedded MM samples was used to search for chromosomal alterations by a comparative genomic hybridization (CGH) method. In two cases, a loss at 9p was found to be the only change. The loss at 9p is a frequent event in malignant mesothelioma and the fact that this anomaly was diagnosed in two sisters as the only alteration suggests that this region may be the site of one or more oncosuppressor genes that could play an important role in the development of MM and in inducing greater genetic susceptibility to the carcinogenic effects of asbestos.