The development of a computer controlled system to simulate in rats, the rapid, frequent changes in oxygen experienced by preterm infants developing retinopathy of prematurity

Preterm infants that develop severe ROP have significantly more fluctuations in their transcutaneous oxygen compared to mild or no ROP, despite the fact that all these infants are kept within clinically 'safe' limits. Current animal models do not accurately reflect this oxygen environment. Our aim was to custom build equipment capable of reproducing the transcutaneous oxygen (TcPO2) levels recorded by infant cotside monitoring equipment in a rat model and assess the equipment's precision. Using previously published data for the rat that translates TcPO2 into the equivalent inspired FiO2, a profile was derived from a datalog of TcPO2 values recorded every minute for 14 days in an infant that had developed severe ROP. This profile was controlled in the animal chamber by software algorithms which calculated the amount and type of gas to be injected to move oxygen to each new set-point. CO2 regulation within the chamber was also possible. Absolute differences between the datalog set-points (n = 17,465) and the oxygen sensor were median 0.3% oxygen, IQR 0.2-0.7% oxygen, with 95% of the differences < +/- 2% oxygen. The equipment is capable of reproducing the oxygen environment experienced by a preterm ventilated infant, giving a satisfactory level of precision.     

Screening for cervical cancer in HIV-infected women receiving care in the United States

OBJECTIVE: We examined the sociodemographic, clinical and provider factors associated with screening for cervical cancer among HIV-infected women. METHODS: We studied a national sample representing 43,490 women receiving treatment of HIV infection who completed first follow-up surveys of the HIV Cost and Service Utilization Study (HCSUS). All women were asked, "In the past 12 months, have you had a Pap test?" Women reporting an abnormal Pap test result were asked whether they had been told antibiotics could cure abnormal cells, and whether they were scheduled for another Pap test or for a colposcopy within 3 months. RESULTS: Of the population represented, 81% had had a Pap test in the past 12 months. Women who reported having a gynecologist and primary care physician at the same clinical site were almost twice as likely (odds ratio, 1.9; 95% confidence interval, 1.3-3.0) as other women to report Pap testing. Among women who reported abnormal Pap test results and were not told antibiotics could cure abnormal cells, 95% were scheduled for a repeat Pap test or colposcopy, but 15% of the women had not received their repeat Pap test or colposcopy. CONCLUSION: Although Pap test rates and appropriate referral for abnormal findings were high among HIV-tested women, many women with initially abnormal Pap test results did not actually receive follow-up Pap testing or colposcopy. Providing gynecologic care at the same site as primary HIV care would likely improve delivery of needed gynecologic care for women.     

Ontogeny of the antibody-forming cell line in mice. III. The generation of mature anti-sheep red blood cell-specific B cells is antigen-dependent.

A role for antigen in the generation of fully mature splenic type B cells has been shown. In adoptive transfer experiments, cells from bone marrow or fetal liver required a longer period to give an anti-sheep red blood cell plaque-forming cell (PFC) response than those from spleen. This delay was not overcome by allowing the cells a 7-day sojourn in the irradiated host before antigen challenge. A two-stage protocol was designed in which the in vivo generation of fully mature cells could be measured by their ability to give PFC in lipopolysaccharide-stimulated cultures in vitro. These experiments showed that a critical factor which influences the final differentiation of bone marrow or fetal liver cells into mature, splenic type B cells is exposure to antigen.     

Vaccination strategies to prevent genital herpes and neonatal herpes simplex virus (HSV) disease

Vaccination strategies to prevent genital and neonatal herpes simplex virus (HSV) disease have a history of apparent efficacy in animal studies followed by failure in clinical trials. Further study of the immune response induced by natural HSV infections in both adults and neonates will provide insight into the requirements for vaccination against acute disease and recurrences. Lessons can also be learnt from the recent partial success of a HSV-2 glycoprotein D vaccine coupled with monophosphoryl lipid A adjuvant, which induced protection from clinical disease in HSV-1 and HSV-2 seronegative women. Its efficacy has been attributed to enhancement of Th-1 immunity by the adjuvant. Newer vaccine vectors including DNA vaccines, recombinant viral vaccines and specific HSV mutants are being developed but better animal models are required for more rapid progress. This review examines the history of HSV vaccine development, describes recent progress towards an effective prophylactic vaccine against HSV and outlines further improvements required to make current vaccines immunogenic to a wide population.     

Carcinoma of the lung and coexistent active pulmonary tuberculosis: diverse morphologic and radiographic presentations

Five patients with coexistent carcinoma of the lung and active tuberculosis within the same pulmonary lesion were studied. These cases represent five distinctly varying radiographic presentations and point out the extreme diversity of the morphological pictures of this particular disease combination. Physicians who regularly deal with patients who might present with either entity alone are cautioned to be alert to the possibility that these two diseases may be present simultaneously within single, specific pulmonary lesions.     

Serum antibody and opsonic responses after immunization with pneumococcal vaccine in kidney transplant recipients and controls.

We immunized 31 renal transplant patients and 6 control subjects with a pneumococcal vaccine containing 14 capsular polysaccharides. Antibody levels to Streptococcus pneumoniae types 3 and 6A were measured by a radioimmunoassay, and opsonic activity to S. pneumoniae types 3 and 6B was determined by using a luminol-enhanced chemiluminescence phagocytic assay on serum samples obtained before and 1 month after immunization. There was a 10.2-fold and a 2.9-fold increase in antibody to S. pneumoniae type 3 (P less than 0.005) and type 6A (P less than 0.01), respectively, but only a 1.3-fold (P greater than 0.05) and 1.1-fold (P greater than 0.05) increase in opsonic activity. For S. pneumoniae type 3, changes in opsonic activity correlated well with antibody concentration (P less than 0.05). However, for S. pneumoniae type 6, these two tests correlated poorly (P greater than 0.05). This poor correlation suggests that concentrations of antibody to type 6A polysaccharide which are achieved after immunization may not be opsonically active in vitro against S. pneumoniae type 6B.     

The diagnosis of recent herpes simplex virus type 2 genital infections by the simplex-2 test.

The prevalence of complement-fixing (CF) antibody against the AG-4 early antigen of herpes simplex virus (HSV) type 2 (HSV-2) was determined in patients with culture confirmed HSV-2 genital herpes and control groups using a commercial HSV-2 early antigen (Simplex-2; Gene Link Australia Ltd). Eighty seven per cent of 39 sera collected between 14 and 28 days after confirmed primary and recurrent HSV-2 infection were positive. In acute sera collected between 2-10 days after onset the Simplex-2 test was negative in all 90 patients with presumed primary infection but positive in 53% of 230 sera from recurrent infection. A specificity of 90-94.5% was obtained by testing 36 patients with recent proven HSV-1 infection and 331 control group patients. The Simplex-2 test may be useful in some cases of culture-negative, clinically suspected genital HSV-2 lesions only when sera are collected between 14-28 days after primary and recurrent infection. Its lack of specificity makes it unsuitable for the routine diagnosis of recent HSV-2 infection in the general population.     

Macular deposits in galactokinase deficiency

Deficiency of the enzyme, galactokinase, is a recognized cause of "juvenile" lens opacities; these opacities are felt to be its only clinical expression. The deficiency itself is inherited as an autosomal recessive and as such is expected to be clinically manifest in the homozygote. We have recently demonstrated cataracts and associated bilateral macular deposits in a white male who is heterozygous for the deficiency of the enzyme and whose dietary intake of milk and its products is extremely high. To our knowledge, intraretinal deposits have not previously been described in patients with galactokinase deficiency, and their clinical significance and biochemical makeup can only be speculative. Dietary restriction of galactose is recommended for all individuals proven to be deficient in this enzyme, whether homozygous or heterozygous.