Demonstration of T Lymphocytes in Cerebrospinal Fluid

Cerebrospinal fluid (CSF) was allowed to drop straight into Hanks's balanced salt solution. After centrifugation the pellet was resuspended and mixed with sheep erythrocytes. The mixture was further handled as in the E-rosette test with peripheral blood lymphocytes. CSF from 20 individuals were investigated, and rosette-forming cells (RFC) were found in all. Six patients with normal fluid had between 46% and 83% RFC. Four patients with multiple sclerosis had increased numbers of RFC (94%-96%). Low numbers of RFC were found in one patient with cerebellar ataxia and in one of two patients with acute viral meningitis. With this technique RFC can be counted even in normal CSF with a 3-ml sample.     

Serologic and molecular detection of granulocytic ehrlichiosis in Rhode Island.

A new indirect fluorescent-antibody (IFA) assay with antigen produced in vitro in the human promyelocytic leukemia cell line HL60 was used to identify the first recognized case of human granulocytic ehrlichiosis in Rhode Island. This IFA assay was used to detect granulocytic ehrlichiae in white-footed mice and in a dog inhabiting the area surrounding the patient's residence. Host-seeking Ixodes scapularis ticks found in the same habitat also were infected. I. scapularis ticks collected from other locations were fed on dogs and New Zealand White rabbits to assess the competency of these species as hosts of granulocytotropic Ehrlichia. Tick-induced infections of dogs were confirmed by serologic testing, tissue culture isolation, and PCR amplification, whereas several rabbits seroconverted but were PCR and culture negative. PCR amplification of the 16S rRNA gene and DNA sequencing of the PCR products or culture isolation was used to confirm granulocytic Ehrlichia infections in humans, dogs, white-footed mice, and ticks.     

Nerve growth factor enhances antigen and other secretagogue-induced histamine release from rat peritoneal mast cells in the absence of phosphatidylserine

The effects of 2.5S nerve growth factor (NGF) and epidermal growth factor (EGF), isolated from mouse submaxillary glands, on histamine release from rat peritoneal mast cells (PMCs) were studied. In the absence of phosphatidylserine, NGF (1 ng/ml to 1 microgram/ml) did not cause histamine release from PMCs isolated from normal rats and those infected with the nematode Nippostrongylus brasiliensis. However, when PMCs (greater than 97% pure) were preincubated with NGF and then challenged with worm antigen (Ag), there was a marked enhancement of histamine release (approximately twofold with a maximum effect at 10 ng/ml of NGF [3.8 X 10(-10) mol/L]) compared with the release induced by Ag alone. EGF (1 ng/ml to 1 microgram/ml) neither produced histamine release from PMCs in the presence of phosphatidylserine nor enhanced Ag-induced histamine release. This suggests that NGF acts directly on PMCs by activation of cell-surface receptors. The early kinetics of Ag-induced histamine release were altered by NGF that increased the initial rate at 15 seconds but did not prolong the overall duration of histamine release. Simultaneous addition of Ag and NGF did not cause enhanced histamine release; thus, some preincubation time with NGF (5 minutes or less) was required for the activation of PMCs. Moreover, after PMCs were activated by NGF, that state persisted for 1 hour, even when unbound NGF was removed by washing, and thereafter subsided gradually. Further studies revealed that NGF enhanced histamine release induced by concanavalin A, compound 48/80, and ionophore A23187. These results suggest that NGF might be an important molecule in inflammatory responses through the regulation of mediator release from mast cells.     

Interstrain variability of larval photokinesis inDrosophila melanogaster

Larvae from seven laboratory strains and eight isofemale lines ofDrosophila melanogaster differ significantly with regard to their responses to light in a photokinesis assay in which the larvae are tested en masse. Larvae from the CA-2 laboratorystock fail to disperse on assay plates, although observations of individual CA-2 larvae suggest that the larvae are repelled by light. Larvae from all of the other laboratory stocks and all of the isofemale lines (except LI2 and NC5) avoid light in the photokinesis assay. Larvae from some stocks are much more strongly repelled by light than larvae from other stocks. LI2 larvae are unresponsive to light in most replicates of the photokinesis assay, while NC5 larvae are consistently unresponsive to light. Observations of F₁ heterozygotes suggest that the allele(s) that affects the vision of LI2 and NC5 larvae has net effects on the animals' behavior that are partially dominant and recessive, respectively.     

Molecular analysis of neutralizing epitopes on outer surface proteins A and B of Borrelia burgdorferi.

The neutralizing epitopes of the major outer surface proteins A and B (OspA and OspB) of Borrelia burgdorferi B31 were investigated by epitope mapping using overlapping synthetic peptides, encompassing full-length OspA and OspB, and antiborrelial monoclonal antibodies (MAbs). OspA MAb N4B12 and OspB MAbs N5G5, W7C2, and P4D1 displayed a complement-independent antiborrelial activity, and complement failed to enhance the antiborrelial activity, as measured by a sensitive colorimetric assay. A combination of N4B12 with N5G5 displayed a higher antiborrelial activity than did the MAbs individually. OspA MAbs B3G11 and L3B5, however, exhibited a significant antiborrelial activity only in the presence of complement. Epitope mapping showed that B3G11 bound to one OspA synthetic peptide with the sequence of amino acids 247 to 256 (QYDSNGTKLE) and produced more than sixfold-higher reactivity than with other sequences, as measured by an enzyme-linked immunosorbent assay. OspB MAb N5G5 bound to an OspB peptide with the sequence of amino acids 211 to 220 (TLKREIEKDG), yielding at least threefold-higher reactivity than with other sequences. These two peptide sequences were found to contain neutralizing epitopes. Other MAbs had weak binding activities with the synthetic peptides, and their specific epitopes remain to be further analyzed. Thus, this study demonstrated both complement-independent and complement-dependent antiborrelial MAbs and identified the linear epitopes on OspA and OspB capable of inducing neutralizing antibody responses.     

Dietary restrictions and fecal occult blood testing

"Unprepped" sigmoidoscopy and fecal occult blood testing were performed simultaneously in 1,000 patients with no dietary restrictions. A total of 102 patients had a positive fecal occult blood test. Of these, 86 had visible blood in the rectum as demonstrated by sigmoidoscopy. Only two of the remaining 16 patients probably had a dietary-induced false-positive result on the occult blood test. Dietary restrictions for guaiac occult blood testing are unnecessary in more than 99 percent of patients.     

Ethics instruction at schools of public health in the United States. Association of Schools of Public Health Education Committee

OBJECTIVES: A survey of US schools of public health was undertaken in 1996 and 1997 to obtain a general picture of public health ethics curricula. METHODS: An explanatory letter with a list of questions for discussion was sent to the deans of the accredited US schools of public health. The deans were asked that at least 1 individual at their school who "is most knowledgeable about ethics curricula" review the list of questions and complete an ethics survey contact form. RESULTS: Ethics instruction was required for all students at only 1 (4%) of the 24 schools surveyed, while 7 schools required ethics instruction for some students. Two of the schools had no ethics courses. Ethics instruction was required for all MPH students at 9 (38%) of the schools and for all doctoral students at 4 (17%) of the schools. Most of the schools (19 of 24, or 79%) offered short courses, seminar series, or invited lectures on ethical topics, and 23 (96%) included lectures on ethics topics in other courses such as health law. CONCLUSIONS: Training programs at US schools of public health vary greatly in how much attention is given to ethics instruction. Model curricula in public health ethics should be developed to help fill this gap.