In vitro and in vivo complementation of Streptococcus mutans mutants defective in adherence

Previous studies have shown that adherence-defective mutants of Streptococcus mutans PS14, serotype c, can be grouped into several different phenotypic groups. In this study a method was developed to test for complementation between pairs of nonadhering mutants which possess different genotypic defects. Mutant strains UAB95 and a spectinomycin-resistant derivative of UAB95 (UAB516) were found to exhibit increased levels of adherence when grown together with UAB230 in media containing sucrose as compared to the adherence of each strain grown separately. An increase in caries was also observed in gnotobiotic rats mixedly infected with the two mutants as compared to either strain alone. Tests revealed that UAB95 produced more water-insoluble glucan than its parent strain but had a defect in glucan binding. UAB230 was found to produce levels of a defective glucan that could not be bound by mutant or wild-type cells. Our results suggest that UAB95 produces a water-insoluble glucan which is bound by UAB230, thus allowing complementation for adherence and caries production.     

Nylon-fiber-induced neutrophil fragmentation

We have investigated the effects of mechanical elution of neutrophils from nylon-wool fiber (NWF) using the scanning electron microscope and biochemical analysis of elution fractions. We have determined that mechanical removal of neutrophils from nylon-wool fiber disrupts neutrophils adherent to nylon-wool fiber and augments release of granules, release of peripheral cytoplasmic fragments, and release of lactic dehydrogenase, a soluble cytoplasmic enzyme. Mechanical shearing of the adherent cell, and not adherence per se, causes the fragmentation. The extent of fragmentation is proportional to the NWF surface area available to neutrophils and is maximal at the temperature for optimal adherence and spreading. Agents that decrease cell spreading (n-ethylmaleimide and cold) diminish fragmentation. Cytochalasin B, an agent that destabilizes the neutrophil cortex, increases fragmentation. Fragmentation may be an important contributing cause of the abnormal morphology, function, and in vivo survival of nylon-wool-fiber procured human neutrophils. The prevention of fragmentation would appear to be necessary to insure the procurement of optimally functioning cells. Elution of NWF-adherent neutrophils in the cold might be a practical way to diminish neutrophil damage during clinical filtration leukapheresis.     

Alloimmunization to platelets in heavily transfused patients with sickle cell disease

Bone marrow transplantation (BMT) is now an option for some patients with sickle cell disease (SCD). Many SCD patients are multiply transfused with red blood cells (RBCs), and may be immunized to alloantigens other than erythrocyte antigens. Because platelet refractoriness is a significant complication during BMT, we wished to determine the prevalence of alloimmunization to platelets in transfused SCD patients. Sera collected from 47 transfused and 14 untransfused SCD patients were screened for HLA and platelet-specific antibodies. Transfusion and RBC antibody histories were reviewed. A subset of the patients were rescreened 1 year later. Eighty-five percent of patients with at least 50 RBC transfusions (22 of 26), 48% of patients with less than 50 transfusions (10 of 21), and none of 14 untransfused patients demonstrated platelet alloimmunization (P < .05). Platelet alloimmunization was more prevalent than RBC alloimmunization (20% to 30%). Half of the platelet reactivity was chloroquine-elutable. Eighteen of 22 patients (82%) on chronic RBC transfusion remained platelet-alloimmunized 11 to 22 months after initial testing. In summary, 85% of heavily transfused SCD patients are alloimmunized to HLA and/or platelet-specific antigens. These patients may be refractory to platelet transfusion, a condition that would increase their risk during BMT. Leukodepletion in the transfusion support of SCD patients should be considered to prevent platelet alloimmunization.     

Immunohistochemical localization of membrane and alpha-granule proteins in human megakaryocytes: application to plastic-embedded bone marrow biopsy specimens

Using a new technique for antigen localization, we have demonstrated platelet proteins in megakaryocytes in plastic-embedded biopsy specimens of normal human bone marrow. In a series of 25 specimens, megakaryocytes showed labeling with antibodies to the integral membrane glycoproteins IIIa, IIb, and the IIb-IIIa complex; granule membrane protein 140; and five alpha-granule matrix proteins: thrombospondin, factor VIII-related antigen, beta-thromboglobulin, platelet factor 4, and fibrinogen. The antibodies to the membrane glycoproteins IIIa, IIb, and IIb-IIIa produced diffuse cytoplasmic staining and heavier staining on the plasma membrane, whereas the antibodies to the alpha-granule matrix proteins produced a distinct granular staining within the cytoplasm. Staining for granule membrane protein 140 was also granular in distribution. Rare mononuclear cells consistent with megakaryocyte precursors were labeled with these markers. Other enzyme histochemical and lectin-binding studies showed that the enzyme alpha-naphthyl acetate esterase, the lectin Ulex europaeus I, and the periodic-acid Schiff reaction were consistent, but not specific, markers of megakaryocytes. This immunohistochemical technique should facilitate the examination of qualitative and quantitative changes in megakaryocytes in a variety of physiologic and pathologic processes.     

Survivorship care in breast cancer: Perceptions of patients and primary care physicians

Objective

To compare the perceptions of breast cancer survivors and primary care physicians (PCPs) about PCPs’ ability to deliver survivorship care in breast cancer.

Design

Mailed survey.

Setting

British Columbia.

Participants

A total of 1065 breast cancer survivors who had completed treatment of nonmetastatic breast cancer within the previous year, and 587 PCPs who had patients with nonmetastatic breast cancer discharged to their care within the preceding 18 months.

Main outcome measures

Breast cancer survivors’ and PCPs’ confidence ratings of PCPs’ ability to deliver the following aspects of care: screening for recurrence; managing osteoporosis, lymphedema, endocrine therapy, menopausal symptoms, and anxiety about or fear of recurrence; and providing nutrition and exercise counseling, sex and body image counseling, and family counseling. Response options for each question included low, adequate, or good. Responses were summarized as frequencies and compared using χ² tests.

Results

Response rates for breast cancer survivors and PCPs were 47% and 59%, respectively. Responses were statistically different in all categories (P < .05). Both groups were most confident in the ability of PCPs to screen for recurrence, but breast cancer survivors were 10 times as likely to indicate low confidence (10% of breast cancer survivors vs 1% of PCPs) in this aspect of care. More breast cancer survivors (23%) expressed low confidence in PCPs’ ability to provide counseling about fear of recurrence compared with PCPs (3%). Aspects of care in which both breast cancer survivors and PCPs were most likely to express low confidence included sex and body image counseling (35% of breast cancer survivors vs 26% of PCPs) and family counseling (33% of breast cancer survivors vs 24% of PCPs). Primary care physicians (24%) described low confidence in their ability to manage lymphedema.

Conclusion

Breast cancer survivors and PCPs are reasonably confident in a PCP-based model of survivorship care. Primary care physicians are confident in their ability to manage physical effects related to breast cancer, with the exception of lymphedema. Low confidence ratings among both groups in psychosocial aspects of care suggest an area for improvement.