Has the mammography quality standards act affected the mammography quality in North Carolina?

OBJECTIVE

The United States Food and Drug Administration implemented federal regulations governing mammography under the Mammography Quality Standards Act (MQSA) of 1992. During 1995, its first year in implementation, we examined the impact of the MQSA on the quality of mammography in North Carolina.

MATERIALS AND METHODS

All mammography facilities were inspected during 1993-1994, and again in 1995. Both inspections evaluated mean glandular radiation dose, phantom image evaluation, darkroom fog, and developer temperature. Two mammography health specialists employed by the North Carolina Division of Radiation Protection performed all inspections and collected and codified data.

RESULTS

The percentage of facilities that met quality standards increased from the first inspection to the second inspection. Phantom scores passing rate was 31.6% versus 78.2%; darkroom fog passing rate was 74.3% versus 88.5%; and temperature difference passing rate was 62.4% versus 86.9%.

CONCLUSION

In 1995, the first year that the MQSA was in effect, there was a significant improvement in the quality of mammography in North Carolina. This improvement probably resulted from facilities' compliance with federal regulations.

Residues of p,p'-DDT and hexachlorobenzene in human milk from Indonesian women

Milk from Indonesian women (n = 4) was analysed for p,p'-DDT and the fungicide, hexachlorobenzene (HCB). p,p'-DDT was found in all of the samples and at levels that are amongst the highest reported anywhere in the world in 3 of the samples. HCB was found in all 4 samples, 1 sample had an exceptionally high level. The high residue of HCB suggested exposure by eating dressed grain, major environmental contamination or direct exposure when handling the fungicide. These are the first data on pesticide residues in milk from Indonesian women which demonstrate general exposure to p,p'-DDT and HCB.

Profilin is required for optimal actin-dependent transcription of respiratory syncytial virus genome RNA

Transcription of human respiratory syncytial virus (RSV) genome RNA exhibited an obligatory need for the host cytoskeletal protein actin. Optimal transcription, however, required the participation of another cellular protein that was characterized as profilin by a number of criteria. The amino acid sequence of the protein, purified on the basis of its transcription-optimizing activity in vitro, exactly matched that of profilin. RSV transcription was inhibited 60 to 80% by antiprofilin antibody or poly-L-proline, molecules that specifically bind profilin. Native profilin, purified from extracts of lung epithelial cells by affinity binding to a poly-L-proline matrix, stimulated the actin-saturated RSV transcription by 2.5- to 3-fold. Recombinant profilin, expressed in bacteria, stimulated viral transcription as effectively as the native protein and was also inhibited by poly-L-proline. Profilin alone, in the absence of actin, did not activate viral transcription. It is estimated that at optimal levels of transcription, every molecule of viral genomic RNA associates with approximately the following number of protein molecules: 30 molecules of L, 120 molecules of phosphoprotein P, and 60 molecules each of actin and profilin. Together, these results demonstrated for the first time a cardinal role for profilin, an actin-modulatory protein, in the transcription of a paramyxovirus RNA genome.

Intravenous immunoglobulin reduces anti-HLA alloreactivity and shortens waiting time to cardiac transplantation in highly sensitized left ventricular assist device recipients

BACKGROUND

Recipients of left ventricular assist devices (LVADs) develop prominent B-cell hyperreactivity. We investigated the influence of anti-HLA antibodies on waiting time to cardiac transplantation in LVAD recipients and compared the effects of 2 immunomodulatory regimens on anti-HLA serum reactivity.

METHODS AND RESULTS

Fifty-five previously nonsensitized LVAD recipients of a TCI device implanted between 1990 and 1996 were studied. Patients with anti-HLA antibodies received monthly courses of either intravenous immunoglobulin (IVIg) or plasmapheresis, in conjunction with cyclophosphamide. The effects of these regimens on anti-HLA alloreactivity and waiting time to transplantation were then determined by Kaplan-Meier log-rank statistics, nonparametric Wilcoxon rank-sum test, and Student's t test. Prolongation in transplant waiting time was related to serum IgG anti-HLA class I alloreactivity. Infusion of IVIg (2 g/kg) caused a mean reduction of 33% in anti-HLA class I alloreactivity within 1 week. Waiting time to transplantation was significantly reduced by IVIg therapy and subsequently approximated that in nonsensitized patients. Side effects of IVIg (2 g/kg) were minimal and related primarily to immune complex disease. Although plasmapheresis caused a similar reduction in alloreactivity to IVIg, this effect was achieved after longer treatment. Moreover, plasmapheresis was associated with an unacceptably high frequency of infectious complications. In patients resistant to low-dose (2 g/kg) IVIg therapy, high-dose (3 g/kg) IVIg was effective in reducing alloreactivity but was associated with a high incidence of reversible renal insufficiency.

CONCLUSIONS

These results indicate that IVIg is an effective and safe modality for sensitized recipients awaiting cardiac transplantation, reducing serum anti-HLA alloreactivity and shortening the duration to transplantation. The therapeutic and safety profile of IVIg would appear to be superior to plasmapheresis.

Structural and functional characterization of an epitope in the conserved C-terminal region of HIV-1 gp120

Through an integrated study of the reactivity of a monoclonal antibody, 803-15.6, with synthetic peptides and native recombinant HIV-1 envelope glycoprotein gp120, we have obtained structure-functional information on a region of rgp120 not yet elucidated by X-ray crystallography. mAb 803-15.6 binds with high affinity and broad cross-clade specificity to the conserved C-terminal region (amino acids 502-516) of HIV-1 rgp120. Phage display selection from a random peptide library identified the core binding motif as AXXKXRH, homologous to residues 502-508. Using quantitative binding analyses, the affinity of mAb 803-15.6 for native, monomeric recombinant gp120HXB2 (rgp120) was found to be similar to that for the synthetic gp120 peptide (502-516). Circular dichroism studies indicate that the synthetic peptide largely has a random coil conformation in solution. The results therefore suggest that the 803-15.6 epitope is fully accessible on rgp120 and that this region of rgp120 is as flexible as the synthetic peptide. Residues 502-504 are on the edge of a putative gp41 binding site that has been postulated to change conformation on CD4 binding. However, the affinity of mAb 803-15.6 for rgp120 is not affected by binding of CD4 and vice-versa. These results suggest either that the 502-504 region does not change conformation upon CD4 binding, or that recombinant gp120 does not undergo the same changes as occur in the native viral gp120-gp41 oligomer. The detailed characterization of the 803-15.6 epitope may be useful for further study of the role of the C5 region of gp120 in the viral attachment and fusion process.

Role of cellular actin in the gene expression and morphogenesis of human respiratory syncytial virus

Cytoskeletal protein actin and nonactin cellular proteins were essential for human respiratory syncytial virus (RSV) gene expression. In vitro, specific antibodies against actin inhibited RSV transcription, whereas antibodies against other cytoskeletal proteins had little or no effect. Affinity purified cellular actin or bacterially expressed recombinant actin activated RSV transcription. However, optimal transcription required additional cellular protein(s) that appeared to function as accessory factor(s) for actin. In the absence of actin, these proteins did not activate viral transcription. Purified viral nucleocapsids contained actin, but no cytokeratin, tubulin, or vimentin. Cytochalasin D or DNasel--agents that destabilize actin polymers--had little effect on RSV transcription. RSV infection itself seemed to alter the structure of the cellular actin filaments. Treatment of infected cells with cytochalasin D produced a more severe disruption of the filaments and drastically reduced the production of infectious virus particles but still had little effect on intracellular synthesis of viral macromolecules. Thus actin seems to serve a dual role in RSV life cycle: its monomeric form as well as polymeric form activate viral transcription, while only the microfilament form may take part in viral morphogenesis and/or budding.

Intrahepatic biliary enteric bypass provides effective palliation in selected patients with malignant obstruction at the hepatic duct confluence

BACKGROUND

Palliating the effects of biliary obstruction is a major goal of therapy in patients with cancer at the hepatic duct confluence. This study was undertaken to evaluate the effectiveness of intrahepatic biliary-enteric bypass to either the segment III duct or the right sectoral hepatic ducts in patients with unresectable hilar cholangiocarcinoma or gallbladder carcinoma.

METHODS

From December 1991 to October 1996, 55 consecutive bypass procedures were prospectively evaluated in patients with unresectable hilar cholangiocarcinoma or gallbladder cancer. Patients were divided into three groups based on the primary tumor and the type of bypass performed: group 1A, cholangiocarcinoma/segment III bypass (n = 20); group 1B, cholangiocarcinoma/right sectoral hepatic duct bypass (n = 14); group 2, gallbladder cancer/segment III bypass (n = 21).

RESULTS

Mean hospital stay (14+/-2 days) and mean blood loss (629+/-84 mL) were similar among the three groups. Perioperative death occurred in 6 patients (11%): 0 in group 1A, 3 each in groups 1B and 2. All survivors had relief of jaundice and pruritus after bypass. Complications occurred in 25 patients (45%). Preoperative transhepatic biliary drainage, performed in 14 patients prior to referral, was associated with a higher incidence of contaminated bile, greater operative blood loss, and postoperative biliary leak that was less likely to resolve spontaneously. Median survival in patients with cholangiocarcinoma (groups 1A and 1B) was 52 weeks and was unaffected by the type of bypass performed. By contrast, median survival in patients with gallbladder cancer (group 3) was 20 weeks; all but 3 died within 32 weeks of surgery. In patients with cholangiocarcinoma, the 1-year bypass patency was 80% in group 1A (segment III bypass) and 60% in group 1B (right sectoral hepatic duct bypass). Overall, there were 9 late bypass failures (18%) requiring reintervention.

CONCLUSIONS

Intrahepatic biliary-enteric bypass effectively relieves symptoms due to malignant hilar obstruction. In patients with cholangiocarcinoma, segment III bypass provides excellent palliation with relatively few late complications and can be performed with minimal morbidity and mortality. Bypass to the right sectoral hepatic ducts, on the other hand, is associated with significant procedure-related morbidity and mortality and more late complications. Patients with gallbladder cancer, because of their poor survival, are probably better palliated by percutaneous biliary stenting.

Immunization with soluble BDC 2.5 T cell receptor-immunoglobulin chimeric protein:antibody specificity and protection of nonobese diabetic mice against adoptive transfer of diabetes by maternal immunization

The BDC 2.5 T cell clone is specific for pancreatic beta-cell antigen presented by I-Ag7, and greatly accelerates diabetes when injected into 10-21-d-old nonobese diabetic (NOD) mice. The BDC 2.5 T cell receptor (TCR) has been solubilized as a TCR-IgG1 chimeric protein. All NOD mice immunized against BDC 2.5 TCR-IgG1 produced antibodies recognizing TCR C alpha/C beta epitopes that were inaccessible on the T cell surface. 56% of the mice produced antibodies against the BDC 2.5 clonotype that specifically blocked antigen activation of BDC 2.5 cells. We have used the adoptive transfer model of diabetes to demonstrate that maternal immunization with soluble TCR protects young mice from diabetes induced by the BDC 2.5 T cell clone.

The beta subunit of human rod photoreceptor cGMP-gated cation channel is generated from a complex transcription unit

Human and bovine rod photoreceptor cGMP-gated cation channel consists of two subunits: alpha (63 kDa) and beta (240 kDa). The human beta subunit was shown to consist partly of sequence encoded by the cDNA clone hRCNC2b. Here we present the complete sequence of the human beta subunit and demonstrate that the previously reported human GAR1 gene encoding a glutamate-rich protein (hGARP) encodes its N-terminal portion. Using PCR, RNA blot and genomic DNA analysis, we provide evidence that the beta subunit is produced from a complex locus on chromosome 16 which is also capable of generating independent transcripts corresponding to GAR1 and the C-terminal two-thirds of the beta subunit. The results indicate that the beta subunit of the cGMP-gated cation channel is produced from an unusual locus consisting of more than one transcription unit.

Human Hsp60: bacterial expression, purification, development of monoclonal antibodies and a sandwich ELISA for quantitation

Bacterial hsp60 proteins are major targets of immune responses during infection, and the highly conserved nature of bacterial and mammalian hsp60 has led to speculation that immune reactivity to these stress proteins may be a component of certain autoimmune diseases. We have developed recombinant proteins and monoclonal antibodies to facilitate further study of human hsp60 and its association with disease. The human hsp60 gene was expressed in Escherichia coli and a method for purification of the recombinant protein essentially devoid of E. coli GroEL was developed. Using the purified protein we have generated a number of monoclonal antibodies which are specific for human hsp60 and do not cross-react with its counterparts from E. coli and mycobacteria. A highly sensitive sandwich ELISA was developed to quantitate hsp60 levels and was used to study hsp60 accumulation in cells due to vaccinia virus infection and heat shock. This ELISA will be useful for monitoring hsp60 levels in body fluids or tissues during autoimmune reactions and/or inflammatory responses.

Prehospital thrombolysis in a rural community: short- and long-term survival

In order to assess the feasibility and outcome of using prehospital thrombolysis in acute myocardial infarction in a rural community, we performed an open randomized study of patients with symptoms of acute myocardial infarction of less than 6 hours. One hundred and forty-five patients with acute myocardial infarction were allocated to receive IV streptokinase prehospital by means of a mobile coronary care unit (MCCU) (n = 43) or to receive IV streptokinase in hospital (n = 102). The mean delay time to treatment was 138 minutes (MCCU group) and 172 minutes (hospital group) (p less than 0.02). Reperfusion time was 88 minutes for the MCCU group and 92 minutes for the hospital group. Mortality at 14 days was 2.3% for the MCCU group and 11.7% for the hospital group (p less than 0.05). Six month mortality was 4.9% for the MCCU group and 17.3% for the hospital group (p = 0.03). Mortality at 1 year was 6.1% for the MCCU group and 20.0% for the hospital group (p = 0.04). There were no significant adverse events in either treatment group. Thus, prehospital thrombolysis by streptokinase is feasible and allows significant reduction in the delay time to treatment initiation. There are encouraging improvements in both short- and long-term survival with no apparent reduction in safety profile.