Effect of excessive GnRH-binding substance on circulating maternal hCG in human pregnancy.

Gonadotropin-releasing hormone (GnRH) can stimulate the release of placental human chorionic gonadotropin (hCG). Thus, at the onset of these studies it was the objective to define the relationship of hCG to GnRH in the maternal circulation throughout pregnancy, focusing on early pregnancy. Blood samples were collected at 8, 10, 12, 14, 16, 28 and 36 weeks of gestation during labor and the GnRH and hCG levels were determined by radioimmunoassay. Of 39 pregnancies, a GnRH-binding substance was found in the maternal circulation of three. This GnRH-binding substance resulted in erroneous GnRH levels, due to the very high non-specific binding. In the pregnant women without this GnRH-binding substance, GnRH attained highest concentrations at 12-14 weeks. The typical peak of hCG at 8-10 weeks of gestation was observed in this group, while the group of patients having the GnRH-binding substance had significantly lower hCG levels. Each of the patients with circulating GnRH-binding substance had prior pregnancy(s) and two of the three had a prior pregnancy loss. The nature of this GnRH-binding substance was investigated using gel chromatography. After incubation of [125I]GnRH with patient plasma for 3 days this substance was shown to be of high molecular weight which was ethanol precipitable. This binding substance may therefore be an antibody, since it appears to be a high molecular weight protein requiring a number of days to bind the [125I] GnRH. This GnRH-binding substance may be of physiological importance, since the circulating hCG level was significantly less in the group of patients with this substance than in those without.

Experimental transmission of Powassan virus (Flaviviridae) by Ixodes scapularis ticks (Acari:Ixodidae).

Transmission experiments were performed with Ixodes scapularis ticks from an uninfected laboratory colony. Immature and adult ticks were exposed to Powassan (POW) viremic hamsters and rabbits, respectively. Oral infection rates for engorged larvae, nymphs and females fed on POW-infected hosts were 10%, 40%, and 57%, respectively. Transstadial transmission rates for nymphs exposed to POW virus as larvae, adults exposed as larvae, and adults exposed as nymphs, were 9.5%, 10%, and 54%, respectively. Evidence of transovarial transmission occurred when two uninfected hamsters, exposed to F2 larvae and nymphs originally exposed to POW virus in the F1 nymphal stage, seroconverted to POW virus with hemagglutination inhibition titers of 80 and 5,120, respectively; the transovarial transmission rate was 16.6%. All developmental stages were able to transmit virus orally to uninfected hosts regardless of when the ticks were originally exposed to the virus. These results suggest that I. scapularis is a competent vector of POW virus under experimental conditions.

Evidence for multiple foci of eastern equine encephalitis virus (Togaviridae:Alphavirus) in central New York State.

A regional surveillance system for eastern equine encephalitis (EEE) virus was established in central New York in 1984 after the 2nd human EEE fatality occurred in 1983. Extensive mosquito surveillance activities were coordinated with the rapid laboratory processing of mosquito specimens for EEE virus. Active surveillance for EEE infections in humans and equines also was initiated. Results of long-term surveillance detected the presence of multiple Culiseta breeding swamps. A 6-yr interepizootic period (1984-1989) was followed by 2 yr of equine EEE. In 1990, there were 7 equine cases and a record number of EEE virus isolations from mosquitoes (n = 86), wild birds (n = 27), and sentinel pheasants (n = 7). In 1991, 7 equine cases also occurred, although there were fewer isolations from mosquitoes (n = 40). The sequence to the appearance of EEE virus at swamps and upland sites and at individual swam complexes, and the spatial and temporal distribution of equine cases provide evidence for multiple foci of EEE virus in central New York. The role of infected Culiseta melanura (Coquillett) in the transfer of EEE virus between swamp and upland areas and among swamp complexes is advanced.

Isolation of Jamestown Canyon and snowshoe hare viruses (California serogroup) from Aedes mosquitoes in western Massachusetts.

Three isolates of Jamestown Canyon virus and one isolate of snowshoe hare virus (California serogroup) were obtained from adult Aedes females collected in western Massachusetts in 1982. Jamestown Canyon virus was isolated from Aedes abserratus/punctor once, and from Aedes intrudens twice. Snowshoe hare virus was isolated from Aedes stimulans group mosquitoes. La Crosse encephalitis (LAC) virus was not isolated from 1,552 adult Aedes triseriatus, nor from 22,557 Aedes triseriatus larvae. However, sera from 1/178 eastern chipmunks, 5/31 gray squirrels, and 8/144 white-tailed deer had neutralizing antibody to LAC virus. No sentinel rabbits placed at sites yielding virus isolates seroconverted to CAL viruses in either year.

Professor Al Nier and his influence on mass spectrometry.

Professor Alfred Otto Carl Nier has had a singular influence on the art and science of mass spectrometry over the last 55 years. I had the pleasure of conducting an oral history interview of Dr. Nier in the spring of 1989 at his office and laboratory at the University of Minnesota. I was assisted in this endeavor by Thomas Krick of the Biochemistry Department staff. The interview was underwritten by the American Society for Mass Spectrometry. The following highlights are excerpted from 10 1/2 hours of material recorded during the interview. The complete set of tapes, a full transcript, pictures, and other material collected during the interview are archived with the Beckman Center for the History of Chemistry in Philadelphia.

Restructuring care: patient focus is key to innovation.

Hospitals across the country are busy reconfiguring their delivery systems to improve patient care delivery. In the process, they are overhauling their organizational structures, reaching out to other institutions for input and participation, and embracing local communities. Many hospital executives are also finding that the path itself is at least as interesting and valuable as the end result.

Oral transmission of Jamestown Canyon virus by Aedes provocans mosquitoes from northeastern New York.

Aedes provocans were allowed to feed on a bloodmeal containing 5.6 log10 TCID50/ml of Jamestown Canyon (JC) virus. After 14 days of incubation at 21 degrees C and 80% RH, 100% (36/36) were midgut infected, 50% (18/36) developed disseminated infections and 50% (9/18) of the latter specimens transmitted virus to capillary tubes. When mosquitoes were intrathoracically inoculated with 6.1 log10 TCID50/ml of JC virus, 100% (40/40) became disseminated infected and 95% (38/40) transmitted virus after 12 days of incubation. A midgut escape barrier was recognized as the major barrier to JC virus transmission in orally infected Ae. provocans.

Incrimination of Aedes provocans as a vector of Jamestown Canyon virus in an enzootic focus of northeastern New York.

A 2-year field study was conducted in southern Saratoga County, New York, to determine which species of the Aedes communis group mosquitoes were potential vectors of Jamestown Canyon (JC) virus. A total of 23,890 mosquitoes (890 pools) were processed for virus isolation in 1988-89, yielding 17 JC virus isolates from Ae. provocans and one isolate each from Ae. communis, Ae. intrudens and Ae. punctor. Minimum field infection rates (MFIR) and daily MFIRs as high as 1:219 and 1:38, respectively, were found in adult female Ae. provocans. Virus isolation attempts from an additional 394 individual Ae. provocans produced a seasonal field infection rate (FIR) of 1:131 and daily FIRs of 1:71 and 1:22. Evidence of transovarial transmission of JC virus was demonstrated by the isolation of virus from 2 pools each of 50 male Ae. provocans reared in the insectary from pupae collected at the study site in 1989. We conclude that Ae. provocans is a potentially important vector of JC virus in northeastern New York.