The human Mr 90,000 heat shock protein and the Escherichia coli Lon protein share an antigenic determinant

1. A monoclonal antibody (TG7A) reacts with a Mr 90,000 mammalian protein, accumulating during virus infection and heat shock. 2. This protein is encoded by a member of the Mr 90,000 heat shock gene family present in a range of organisms form yeast to man. 3. The antibody also recognises a Mr 94,000 protein in E. coli which similarly accumulates in virus infection and heat shock. 4. This protein has been identified as the Lon protease of E. coli. 5. The shared epitope and similar stress inducibility of the two proteins suggests that a functional and/or evolutionary relationship exists between them.     

Human sperm–egg binding is inhibited by peptides corresponding to core region of an acrosomal serine protease inhibitor

An antiserum, designated R4 and raised against denatured hamster acrosomes, was shown to localize specifically to the acrosomal region of hamster, rat, mouse, and human spermatozoa, and to inhibit both hamster and human sperm–oocyte binding in vitro. Following screening of a human testis λgt11 cDNA expression library with the antiserum R4, a series of cDNA clones were isolated. One (cDNA 134) was selected based on the ability of the β-galactosidase fusion protein to inhibit human and hamster sperm–zona binding in vitro. The fusion protein was also shown to inhibit the penetration of zona-free hamster oocytes by human spermatozoa. Sequence analysis revealed that cDNA 134 coded for a portion of a serine protease inhibitor (serpin) closely related to plasma Protein C inhibitor. Sequencing of an additional cDNA clone (261) and Northern blot analysis confirmed that a Protein C inhibitor-like mRNA is synthesised in the human testis. Affinity-purified anti-134 antibody specifically localized to the acrosomal region of both hamster and human sperm. Synthetic peptides corresponding to the conserved core region responsible for the interaction of the serpin with its cognate protease also blocked human sperm--zona binding in vitro. The results suggest that this acrosomally located inhibitor plays an important role in the series of binding events that results in human fertilization. © 1993 Wiley-Liss, Inc.     

Cost of primary health care services in the emergency department and the family physician's office.

An attempt has been made to determine the true cost of providing primary health care for nontraumatic conditions in the emergency departments of two hospitals in Ontario and in the offices of family physicians. A total of 1117 patients presenting with 1 of 10 common symptom/sign complexes at the emergency departments or the offices of 15 participating family physicians were studies with regard to number of visits made, type of assessment by the physician, investigations undertaken, management, therapy and outcome of the illness. Costs were calculated from the charges that would be made against the provincial health services insurance plan and from the system of hospital financing in effect in the province. The average true cost per illness episode of this type of care was $14.63 in hospital A, $14.20 in hospital B and $15.90 in the family physician''s office.     

Characterization of a novel T lymphocyte protein which binds to a site related to steroid/thyroid hormone receptor response elements in the negative regulatory sequence of the human immunodeficiency virus long terminal repeat.

We have previously identified a T lymphocyte protein which binds to a site within the LTR of the human immunodeficiency virus type 1 (HIV-1) and exerts an inhibitory effect on virus gene expression. The palindromic site (site B) recognized by this protein is related to the palindromic binding sites of members of the steroid/thyroid hormone receptor family. Here we characterize the T cell protein binding to this site as a 100 kD protein which is most abundant in T cells and which binds to site B as a 200 kD complex. This protein is distinct from other members of the steroid/thyroid hormone receptor family including the COUP protein which has a closely related DNA binding specificity.     

Novel cell lines display properties of nociceptive sensory neurons

Hybrid cell lines derived from neonatal rat dorsal root ganglia neurons fused with the mouse neuroblastoma N18Tg2 exhibit sensory neuron-like properties not displayed by the parental neuroblastoma. These properties include an inward (depolarizing) current with a conductance increase in response to activation of a bradykinin receptor, an inward (depolarizing) current with a conductance increase in response to the sensory excitotoxin capsaicin, the expression of sensory neuropeptides (substance P, CGRP and somatostatin), the expression of phosphatidylinositol-anchored molecules including adhesion molecules of the immunoglobulin superfamily that can be regulated in serum-free culture by nerve growth factor (N-CAM, F-3 and Thy-1), and low permissivity to herpes simplex virus infection. These lines thus provide appropriate models for the study of mechanisms involved in nociceptor activation and the regulation of expression of sensory-neuron specific markers including neuropeptides.