Demonstration of contacts between proopiomelanocortin neurons in the rat hypothalamus

The relationships between proopiocortin neurons have been studied in the rat hypothalamic arcuate nucleus by immunocytochemistry. At the light microscopic level, contacts between immunostained endings and cell bodies or dendrites were frequently observed. At the electron microscopic level, stained nerve terminals were seen making symmetrical synaptic contacts with labeled dendrites and cell bodies. These observations are the first indication that neurons producing the same peptides can have contacts between themselves. This provides morphological evidence for autoregulation of neuropeptide systems.

Serogrouping and subtyping of Legionella pneumophila with monoclonal antibodies

Monoclonal antibodies directed against Legionella pneumophila serogroups 1 to 6 were produced by fusing splenocytes of BALB/c mice with the Sp 2/0-Ag14 or the NSO mouse myeloma cell lines. Specificity of these antibodies was determined by indirect fluorescent-antibody staining: 8 reacted with L. pneumophila serogroup 1 and, respectively, 13, 6, 6, 5, and 10 reacted with serogroups 2, 3, 4, 5, and 6; all except 5 were serogroup specific, and none presented cross-reactions with six other species of Legionellaceae. Serogroup determination of 35 isolates of L. pneumophila with seven selected monoclonal antibodies resulted in correct serogrouping in all instances; a pool of the same seven monoclonal antibodies stained intensely all strains of L. pneumophila without any staining of the other species of Legionellaceae. When 24 serogroup 1 isolates of L. pneumophila were stained with eight serogroup 1-specific monoclonal antibodies, the staining patterns could be clustered in five distinct groups. These hybridomas thus represent an unlimited source of standard reagent that could be used in the detection and serogrouping of L. pneumophila; differences in staining patterns could be used as epidemiological markers for these bacteria.

Tests for monotone mean residual life, using randomly censored data

At any age the mean residual life function gives the expected remaining life at that age. Reliabilists and biometricians have found it useful to categorize failure distributions by the monotonicity properties of the mean residual life function. Hollander and Proschan (1975, Biometrika 62, 585-593) have derived tests of the null hypothesis that the underlying failure distribution is exponential, versus the alternative that it has a monotone mean residual life function. These tests are based on a complete sample. Often, however, data are incomplete because of withdrawals from the study and because of survivors at the time the data are analyzed. In this paper we generalize the Hollander-Proschan tests to accommodate randomly censored data. The efficiency loss due to the presence of censoring is also investigated.

Incidence of hepatitis non-A, non-B compared with types A and B in hospital patients

To establish the relative frequencies of types A, B and non-A, non-B hepatitis, stored samples of blood from all the cases of acute viral hepatitis seen over a period of 9 years in a general hospital for adults were classified according to their type by presently available serologic methods. The study included 456 episodes of hepatitis in 447 patients, distributed as follows: 114 episodes of hepatitis A (25%), 282 of hepatitis B (62%) and 60 of hepatitis non-A, non-B (13%). The episodes of non-A, non-B hepatitis were equally distributed between the sexes, suggesting a mode of transmission different from that of hepatitis A or B, which had male/female ratios of 2.4 and 3.1 respectively. The low proportion of hepatitis non-A, non-B may not reflect its real frequency, since it often escapes clinical recognition.

Polymorphic variants in human chromosome 15

We found eight polymorphic variants in human chromosome 15 using Q, C, Q-C and Ag-NOR staining methods. These variants included brightly or dully fluorescent pericentric segments and satellites, giant satellites, increased amounts of short arm hetrochromatin (ph+) and darkly (C band-positive) or lightly (C band-negative) Giemsa-stained pericentric Q-negative segments. These staining properties indicated that the entire short arm of 15 contained at least four distinct chromatin segments: Q-negative centromeric heterochromatin, a Q-variable distal segment, a Q-negative satellite stalk, and Q-variable satellites, in that order, from proximal to distal ends. The BrdU-Hoechst 33258-stained R bands (RBH) and high resolution G subbands were also studied for karyologic characterization of chromosome 15. Most of these variants were reported also in 13, but insufficiently documented in other D and G chromosomes. Together with polymorpic pericentric fluorochromes seen in 3 and 4, Yq, and nonpathogenic t(D;Yq), the pattern of these variants can be used as karyologic fingerprints for identification of each individual and his or her cell explants both in vivo and in vitro.