Pertussis in Massachusetts, 1981-1991: incidence, serologic diagnosis, and vaccine effectiveness

Massachusetts provides diphtheria-tetanus toxoid-pertussis (DTP) vaccine, and since 1980 has monitored pertussis with a statewide diagnostic service. The incidence of bacteriologically confirmed pertussis was 104.5 per 100,000 person-years in 1-month-old infants and declined progressively thereafter. Infants < 6 months old experienced disproportionate morbidity: 44% of bacteriologically confirmed pertussis, 64% of hospitalizations, and 71% of hospital days. Most children with pertussis had received < 3 DTP doses during childhood, whereas 87% of adolescents with pertussis had received > or = 4 doses. Serodiagnosis by single serum anti-pertussis toxin antibody ELISA increased the incidence of confirmed pertussis in persons 11-19 years old from 3.0 to 12.9 per 100,000 and in persons > or = 20 years old from 0.16 to 0.56 per 100,000. Bacteriologic methods underestimate pertussis incidence, but a single serum anti-pertussis toxin antibody ELISA is a practical method for population-based diagnosis in adolescents and adults.     

Autoantibodies against endothelial cells, extracellular matrix, and human collagen type IV in patients with systemic vasculitis

Endothelial cells and subendothelial matrix (ECM) are involved in the pathogenesis of vasculitis. Exposure of the ECM following vascular damage may promote further immune and inflammatory response. To investigate this, we studied the prevalence of antibodies against endothelial cells (AECA), ECM, and its major component collagen type IV in systemic vasculitis patients. Seventy-one percent of patients had AECA (binding index, means +/- SD: 64.8 +/- 48.1%; normal controls: 8.9 +/- 6.9%, P < 0.001). Anti-ECM and anti-collagen type IV antibodies were also significantly higher in patients compared to normals (anti-ECM: 28.6 +/- 29.6% vs 9.0 +/- 11.3%, P < 0.002; anti-collagen type IV: 23.5 +/- 20.3% vs 8.1 +/- 9.1%, P < 0.002). AECA correlated with anti-ECM (r = 0.75, P < 0.0001) but not with anti-collagen type IV. Anti-ECM correlated with anti-collagen type IV (r = 0.45, P < 0.01). Positivity of cytoplasmic anti-neutrophil cytoplasmic antibodies (cANCA) was significantly lower in patients positive for anti-ECM and/or anti-collagen type IV antibodies (58% vs 11%, P = 0.048). AECA binding was partially reduced with ECM incubation by 25.1%. The addition of heparin caused a dose-dependent inhibition of binding activity (19.2-30.6%) in the AECA ELISA. These results support the hypothesis that there is a humoral response against ECM components in addition to endothelial cells in systemic vasculitis patients which might have pathological significance in vascular damage.     

The cell tropism of human immunodeficiency virus type 1 determines the kinetics of plasma viremia in SCID mice reconstituted with human peripheral blood leukocytes

Most individuals infected with human immunodeficiency virus type 1 (HIV-1) initially harbor macrophage-tropic, non-syncytium-inducing (M-tropic, NSI) viruses that may evolve into T-cell-tropic, syncytium-inducing viruses (T-tropic, SI) after several years. The reasons for the more efficient transmission of M-tropic, NSI viruses and the slow evolution ofT-tropic, SI viruses remain unclear, although they may be linked to expression of appropriate chemokine coreceptors for virus entry. We have examined plasma viral RNA levels and the extent of CD4+ T-cell depletion in SCID mice reconstituted with human peripheral blood leukocytes following infection with M-tropic, dual-tropic, or T-tropic HIV-1 isolates. The cell tropism was found to determine the course of viremia, with M-tropic viruses producing sustained high viral RNA levels and sparing some CD4+ T cells, dual-tropic viruses producing a transient and lower viral RNA spike and extremely rapid depletion of CD4+ T cells, and T-tropic viruses causing similarly lower viral RNA levels and rapid-intermediate rates of CD4+ T-cell depletion. A single amino acid change in the V3 region of gp120 was sufficient to cause one isolate to switch from M-tropic to dual-tropic and acquire the ability to rapidly deplete all CD4+ T cells.     

Novel attributes of an androgenic steroid-mediated increase in cardiac end diastolic stiffness in rats

The expression of ras was investigated by using immunohistochemistry in 245 primary colorectal adenocarcinomas and 49 corresponding metastases in the lymph nodes. One hundred and forty-four (59%) of the primary tumours presented as ras positive and 37 (76%) were positive in metastases. The ras expression was positively related to cell proliferation (p=0.01) and significantly increased in tumours with aneuploidy (68%) compared to tumours with diploidy (51%) and tetraploidy (53%, p=0.01). The frequency of ras expression was increased from Dukes' stage A to stages B-D (41% vs 62%, p=0.01). ras expression was compared in 40 paired primary tumours and their corresponding metastases, and the difference in expression did not reach statistical significance (73% vs 83%, p=0.32). In survival analyses, ras overexpression predicted a poor prognosis independent of Dukes' stage, DNA ploidy and S-phase fraction (p=0.049). We did not find any significant relationship between ras expression and patients' sex, age, tumour location, growth pattern, differentiation, p53 expression or heat shock protein. The results indicate that the alteration of ras expression may be involved in the instability of DNA and cellular overproliferation, but not in the progression to advanced stage and the development of metastases. The expression of ras was an important biological marker for evaluating the prognosis in patients with colorectal adenocarcinoma.     

A comparison of placebo response with major depressive disorder in patients recruited through newspaper advertising versus consultation referrals

Recent evidence indicates few differences between patients recruited through advertising and by consultation referral, and there is some suggestion that those recruited through advertising are more representative of the target community population. However little has been reported on differences in placebo response and compliance in these two patient groups. We conducted a retrospective chart review of 49 patients with major depressive disorder (MDD), recruited through advertising or consultation, randomized to placebo in five clinical trials. Variables included demographics, clinical history, efficacy, compliance, and completion data. Homogeneity was demonstrated for most variables. Differences in placebo groups included significantly lower Hamilton Rating Scale for Depression (HAM-D) scores for the advertisement group throughout the trials. Advertisement patients were also more likely to be early placebo responders and in remission at Days 14 and 28. No differences were found in completion rates or reasons for early termination. Compliance was excellent for both groups. Early placebo response of the advertisement group reinforces the need for trials of at least 8 weeks. In addition, consultation patients may have a more severe illness and be treatment resistant, suggesting they are less generalizable to community practice populations.     

Characterization of (1'R,4S,4aR,7S,7aR)-dihydronepetalactol as a semiochemical for lacewings,including Chrysopa spp. and Peyerimhoffina gracilis

The enantiomerically pure diastereoisomers (1R,4S,4aR,7S,7aR)- (1) and (1R,4R,4aR,7S,7aR)-dihydronepetalactol (2) were synthesized diastereoselectively from a renewable resource, (4aS,7S,7aR)-nepetalactone (3), isolated as the main constituent of the essential oil of the catmint plant Nepeta cataria. The stereochemistry of the compounds was determined by NMR spectroscopy and X-ray crystallography, and the compounds were identified, respectively, as neomatatabiol and isoneomatatabiol, natural products from Actinidia polygama, for which the lactol stereochemistry was previously incompletely defined. Compound 1 was found to catch significant numbers of three species of lacewing in the field: in Korea, Chrysopa cognata, and in the United Kingdom, Nineta vittata and most notably Peyerimhoffina gracilis. All species caught in significant numbers were found more frequently in traps releasing 1 than 2, while more C. cognata, C. formosa, and C. phyllochroma were found in traps releasing (1R,4aS,7S,7aR)-nepetalactol (4). The catch of P. gracilis with 1 is of particular interest as this lacewing has only recently been recorded in the United Kingdom. Where sexed, the lacewings of all species trapped were found to be male, implying a possible pheromonal role for these or structurally related compounds.     

Nucleation and crystallization of polypropylene by mineral fillers: relationship to impact strength

The mechanical properties of mineral-filled polypropylene (PP) are determined not only by the size, shape and modulus of the filler particles, but also by microstructure. For example, poor impact strength is correlated with a high capacity for nucleation of crystallization. In the present study, optical microscopy has been used to measure the growth rate of spherulites in PP. In tandem with this, isothermal d.s.c. measurements have been made of the crystallization of the PP filled with talc, calcium carbonate and stearate-coated carbonate at different loading levels. Computer simulation of spherulite growth has been used to derive the number of nucleating sites per unit volume of polymer and, using surface area measurements, the number of sites per unit area of mineral surface was obtained. Values for talc were, as expected, considerably higher than those for carbonate (and especially coated carbonate) fillers. The presence of filler affects not only the nucleation and kinetics of the crystallization process but also the crystallinity and orientation indices and the proportion of β-phase crystallites present. The connection between these factors and impact strength is discussed. It is concluded that impact properties are determined by inter alia crack pinning and blocking by filler particles, stress concentrations at the edges of the filler particles, and the nucleating ability of the filler.