In vivo modulation of 17 beta-estradiol-induced vitellogenin synthesis and estrogen receptor in rainbow trout (Oncorhynchus mykiss) liver cells by beta-naphthoflavone

Vitellogenesis or egg yolk production represents a key estrogen initiated process in oviparous vertebrates which is crucial for oocyte maturation. Previous in vitro studies have shown that cytochrome P4501A1 (CYP1A1)-inducing compounds such as beta-naphthoflavone (betaNF) modulate 17 beta-estradiol-induced vitellogenin (Vg) synthesis in primary cultures of juvenile rainbow trout liver cells. In this study, treatment of juvenile trout with 0.5 mg/kg 17 beta-estradiol plus either 25 or 50 mg/kg betaNF confirmed in vivo that betaNF may depress Vg synthesis by the liver. Alternatively, trout treated with 0.5 mg/kg 17 beta-estradiol plus 12.5 mg/kg betaNF or 5 mg/kg 17 beta-estradiol plus 12.5, 25, or 50 mg/kg betaNF showed a potentiation of Vg synthesis relative to estradiol-only injected fish. These results are significant as they suggest that changing plasma estrogen levels in sexually maturing trout will determine whether or not CYP1A1-inducing compounds may suppress, have no effect, or potentiate estrogen-induced liver Vg synthesis. Depressed Vg synthesis by trout injected with 0.5 mg/kg 17 beta-estradiol plus 50 mg/kg of betaNF correlated with depressed estrogen-binding capacity of liver, as assessed by [3H]17 beta-estradiol binding to liver nuclear protein extracts. Using gel mobility shift assay, the decrease in estrogen responsiveness of liver was not attributed to depressed estrogen response element-estrogen receptor binding. The fish liver vitellogenesis process offers a comparative model with which to further study the mechanism(s) of aryl hydrocarbon receptor-mediated antiestrogenicity and endocrine disruption.

Recreational patterns, body composition and socioeconomic status of Western Australian secondary school students

A study of 4672 secondary school students was carried out in order to assess the relationship between body composition, recreational patterns, and socioeconomic status as indicated by parental occupation and the school attended. Results indicated that there were more girls than boys participating in organized sport, and health and fitness activities; and more boys than girls involved in informal recreational activities and home-based passive pursuits. A higher proportion of participants came from the higher socioeconomic status (SES) group. More high-SES students revealed weight appropriate to their height.

Molecular typing by random amplification of polymorphic DNA and M13 southern hybridization of related paired isolates of Aspergillus fumigatus

Three forms of DNA-based typing procedures for Aspergillus fumigatus isolates have been developed over the last five years. The procedures are random amplification of polymorphic DNA (RAPD), restriction fragment length polymorphism (RFLP) detection, and Southern hybridizations with various repetitive sequence-based probes. Using two of these procedures, we compared 16 selected isolates, grouped into eight pairs on the basis of epidemiology or previously assigned RFLP types. RAPD with four primers (R108, RC08, 2, and 4), including three previously used with A. fumigatus, showed that one primer, R108, gave the best discrimination (8 types). Southern hybridization of total genomic DNA digested with HindIII and probed with the total bacteriophage M13 genome resulted in the highest overall level of discrimination. Combination of the RAPD and Southern hybridization with the previously assigned RFLP types discriminated 10 isolates of 16. Isolates closely linked epidemiologically could not be distinguished from each other. In addition, three pairs of isolates previously unlinked by epidemiology had the same overall types. Two pairs were obtained from the same hospital within 2 years of each other, whereas the third pair were isolated from California and Germany. A full understanding of the epidemiology and ecology of A. fumigatus requires multiple discriminatory typing procedures.

Erratic deposition of agrin during the formation of Xenopus neuromuscular junctions in culture

In order to disclose the mechanism that regulate synapse development we compared the distributions of agrin, acetylcholine receptors (AChR) and a basal lamina heparan sulfate proteoglycan (HSPG) in sections and cultures prepared from Xenopus laevis and Ambystoma mexicanum embryos. While agrin, AChR and HSPG may accumulate almost synchronously at synapses in vivo, agrin deposition usually lagged well behind the other synaptic markers during development in culture, and was not detectable at many differentiated junctions. Agrin deposition at nerve-muscle contacts in culture also appeared to require the presence of other synaptic components. A similarly variable deposition occurred on noninnervated myocytes, where agrin again collected near sites of HSPG and AChR accumulation on some cells. Profuse agrin accretion occurred consistently, however, within the extracellular matrices of surrounding epithelial cells derived from both myotomes and neural tubes. In cocultures of Ambystoma neurons and Xenopus myocytes Ambystoma agrin collected at some chimeric neuromuscular junctions, but also accumulated on noninnervated myocytes and in the extracellular matrices of salamander neuroendothelial cells. Based upon these observations we conclude that (a) focal agrin deposition is not required for synaptic differentiation on Xenopus myocytes and (b) agrin may be one of several muscle basal lamina components that stem mainly from the secreted products of nearby epithelial cells.

The relationship between carbon dioxide sensitivity and sprint or endurance performance in young swimmers

There has been some evidence that extremes of CO2 sensitivity can indicate an individual's potential for sprint or endurance athletic performance. This study examined the responses to CO2 rebreathing, and previously validated sprint and endurance tests by subjects who were involved in regular, but not intensive, swimming training. The aim was to determine whether subjects with low CO2 sensitivity might perform better on endurance tests, whilst those subjects with high CO2 sensitivity would be more successful in the sprint tests. Initially, 168 young (mean mean(s.d.) age = 12.4(2.1) years) swimmers were measured using a modified version of the Read CO2 rebreathing technique. From this sample, 17 high (mean means(s.d.) = 2.24(0.39) 1 min-1 mmHg-1) CO2 responders were matched by gender, age, height, weight and FVC with 17 low (mean means(s.d.) = 0.57(0.19) 1 min-1 mmHg-1) responders. Each of these 17 pairs underwent two sprint tests (10 s Tri-level alactic power, 50 m run) and two endurance tests (PWC170, 1.6 km run) in order to determine whether any differences existed between the two groups and the sprint and endurance parameters. The subjects remained unaware of their results of the rebreathing test throughout testing. A dependent t test was then used to compare the results collected from each group. The low CO2 responders recorded a significantly faster 1.6 km run time, but were not superior on the PWC170 ergometer test, than the high CO2 responders. The high CO2 responding group recorded significantly higher results on the 10 s alactic power test, but not the 50 m sprint run, than the low responders. Hence, further study is required to ascertain underlying causes as to why significant differences occurred with CO2 rebreathing, the 1.6 km run and the 10 s alactic power test, but not with the PWC170 and the 50m sprint run.

Molecular typing of Aspergillus species

In the last four years, several molecular typing methods have been applied to various Aspergillus species, primarily A. fumigatus and A. niger. Many 'clones' or DNA types exist in the environment and in patients. The most discriminatory methods appear to be restriction fragment length polymorphism analysis with or without specific probes and random amplification of polymorphic DNA analysis. Insufficient work on interlaboratory reproducibility has been done. Most patients are infected by single DNA types, although occasionally multiple isolates are detected. Little work has been done with regard to detailed hospital epidemiology using molecular typing methods.

The relationship of hypercapnic ventilatory responses to age, gender and athleticism

When a gas mixture containing carbon dioxide (CO2) is inhaled by an individual, alveolar ventilation is increased. This ventilatory response to CO2 highlights the relationship between the increase in exercise ventilation and the increase in alveolar CO2 pressure (paCO2). This response is mediated centrally by brainstem chemoreceptors in the medulla and, to a lesser extent, peripherally by the carotid and aortic bodies. However, the response of increased breathing to rising paCO2 varies markedly among individuals. The responses to CO2 rebreathing have been investigated by a variety of research groups for different reasons. The range of responses by children and adults including: gender differences; responses by athletes; the relationship between age and body size; and whether it is an acquired or inherited response have been studied. The following is a summary of these different aspects of CO2 rebreathing has been complied to assist researchers studying any single or multiple facets of the area.

Total hip replacement for developmental dysplasia of the hip

Total hip arthroplasty relieves pain and improves function for many patients with endstage arthritis secondary to developmental dysplasia of the hip. Acetabular dysplasia, however, presents a special problem for total hip reconstruction in these patients. Structural bone grafting with femoral head autografting to the dysplastic acetabulum and cementing acetabular components into the graft provides satisfactory short-term results, but longer-term followup data show high acetabular component failure rates. At a mean followup period of 7 years, 20% of components were loose, and at a mean followup period of 12 years, 46% were loose. Noncemented porous-coated hemispherical acetabular components have considerably expanded the success of total hip replacement without the need for structural bone grafting in such patients. At a mean followup period of almost 7 years, none of the acetabular components were reported to be loose in 1 series. For most patients, the acetabular dysplasia can be managed by techniques such as reaming deeper, using small-diameter porous-coated acetabular components, using screws to provide rigid initial stability for the components, increasing the height of the prosthetic hip center, and covering small portions of the components with bone graft chips if necessary.

Neuronal differentiation in vitro from precursor cells of regenerating spinal cord of the adult teleost Apteronotus albifrons

This study documents neuronal differentiation in vitro from undifferentiated precursor cells of caudalmost regenerating spinal cord of the teleost Apteronotus albifrons. At 11 days in vitro, cells from the caudalmost tip of the regenerating cord are flat and polygonal in shape, lack neuronal processes and do not stain with antibody against neuron-specific filaments. At 15 days in vitro, some of the caudalmost cells have developed short, neurite-like processes; at 18 days in vitro, some cells react positively with antibody against neuron-specific filaments. At 26 days in vitro, many of the caudalmost cells have long branching neurites and react positively with anti-neurofilament antibody. Addition of insulin-like growth factor-I to the medium accelerates the process of neuronal differentiation from the caudalmost precursor cells in vitro. The source of these precursor cells is ultimately cells of the ependymal layer of adult spinal cord. Further investigation of the factors that control production and differentiation of these cells will be important in defining the developmental potential possible for vertebrate spinal cord cells and may aid in creating an optimal environment for regeneration of axons within mammalian spinal cord.

The influence of sometribove dose and days in lactation on behavior of cows implanted with pelleted sometribove

Data were from observations of behavior of 99 lactating Holstein cows during implantations with bST. Implantations were at 14-d intervals during 1 yr. Cows on one study received 0, 120, 240, or 360 mg; cows on a second study received 0, 160, or 320 mg of bST per implantation. A checklist of behaviors was completed by the recorder and observer for each cow during implantation. Cows were also given an overall temperament score during each session. Lunging occurred in 49% of the sessions, but bellowing, kicking, and kneeling occurred least. More cows scored in the docile range than in the excited range. Cows habituated to head bobbing, back sagging, lunging, moving back in chute, flinching, head up, and bellowing, but not to shifting feet, kicking, shaking the head, head back, or ears back.

Effect of dexamethasone and oxygen exposure on neonatal rat lung retinoic acid receptor proteins

Retinol deficiency in animal models results in histopathologic airway changes that appear similar to those found in human premature infants with bronchopulmonary dysplasia (BPD). Dexamethasone (DEX), a steroid now often used in the treatment of BPD, might potentially affect lung vitamin A homeostasis since it alters serum and liver retinoid stores in certain models. Our objective was to determine the effect of DEX on neonatal rat lung retinoid status and the binding of retinoic acid (RA) to cytosolic and nuclear receptor proteins. We examined this effect both in room air and when the animals breathed 95% oxygen (O2). Twenty-four 1-day-old rat pups received either 1 microgram/g DEX subcutaneously, an equal volume of normal saline (NS) subcutaneously at 0 (start experiment time), 24, and 48 hours, or no injection at all, and were sacrificed at 72 hours. Twelve rats in each treatment group were housed in room air and 12 in each group were exposed to > 95% O2 for the 3 day period. Lung and liver were analyzed for retinyl palmitate (RP). Nuclear retinoic acid receptor (RAR) and cellular retinoic acid binding protein (CRABP) were measured by specific binding assays. DEX decreased liver RP by 33-55% and rat pup lung RP by over 60%; it also decreased lung RAR binding (mean dpm/microgram protein +/- SEM) in both room air and oxygen groups: Air (11.2 +/- 1.0) vs. Air/DEX (4.6 +/- 1.3, n = 6; P < 0.01), and O2 (18.2 +/- 0.6) vs. O2/DEX (3.2 +/- 0.6, n = 6; P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Chromosome 13 transfer provides evidence for regulation of RB1 protein expression

The human retinoblastoma susceptibility gene (RB1) located on chromosome 13 has been shown to function as a growth/tumor suppressor gene in a large number of human cancers. Although constitutive expression has been observed in most cultured cells and normal tissues, overexpression of RB1 protein has not been well documented. Perhaps regulating the level of normal RB1 protein expression is one of several ways of controlling its function. To test this hypothesis, we transferred normal copies of chromosome 13 via microcell fusion into the human fibrosarcoma cell line HT1080. Microcell hybrids were generated that contained one, two, or three extra copies of the transferred fibroblast chromosome 13. Compared to the parental cell line, the hybrids were completely unaltered with respect to several properties in vitro and in vivo, including morphology, growth rate, and tumor formation. Northern blot analysis revealed a stepwise increase in RB1 mRNA expression which increased in proportion to the number of alleles present in each cell line. Although RB1 protein exhibited correct nuclear localization and was phosphorylated in a normal cell cycle-dependent manner in the hybrids, the increased level of protein expression in each hybrid was nearly identical and did not increase beyond a threshold amount, although mRNA expression continued to increase. These results demonstrate that HT 1080 cells can tolerate an increase level of RB1 protein, but that expression beyond a certain level may be down-regulated. These transfer studies provide evidence for regulation of RB1 protein expression and may suggest an alternative form of monitoring and controlling normal RB1 functioning.

Evidence that wild-type TP53, and not genes on either chromosome 1 or 11, controls the tumorigenic phenotype of the human fibrosarcoma HT1080

The specific transfer of normal chromosomes via microcell fusion has been instrumental in identifying putative tumor suppressor gene loci in a variety of human cancers. Using this same technique it has been proposed that the tumorigenicity of the human fibrosarcoma cell line HT1080 is controlled by functionally distinct tumor suppressor genes on human chromosomes I and II. To address these results and perhaps further localize the suppressive effect to particular regions on these two chromosomes, we transferred into HT1080 seven different fibroblast-derived human chromosomes containing either intact or discrete portions of chromosome I or II. Interestingly, we found no evidence of genes on these chromosomes that could alter the growth of HT1080 either in vitro or in vivo. Based on these results we were left with the possibility that a gene, or genes, residing on an entirely different chromosome(s) was involved in the tumorigenesis of HT1080. Since TP53 mutation has been documented in a variety of human tumor types, and we found both copies of TP53 to be mutated in HT1080, we were prompted to examine its role by both cDNA transfection and chromosome transfer. Although by cDNA transfection we found that expression of exogenous wild-type TP53 was incompatible with continued proliferation of HT1080 cells in vitro, chromosome 17 transfer studies revealed that a more physiologic expression of exogenous wild-type TP53 could be tolerated in vitro while being completely incompatible with growth in vivo. These studies demonstrate a differential effect of TP53 growth inhibition and clearly show that TP53 tumor suppressing function can be independent from its potent growth suppressing effect in vitro.

Characterisation of the novel gene G11 lying adjacent to the complement C4A gene in the human major histocompatibility complex

Twelve transcriptional units have now been located in a 160 kb segment of DNA that includes the genes encoding members of the serum complement system C2, Factor B (Bf) and C4 within the class III region of the human major histocompatibility complex (MHC). The common arrangement of these genes is tel-C2-Bf-RD-G11-C4A-[P450c21A-YA-XA]-C4B-[P450c21B-YB ]-+ ++TNX-cen. Characterisation of cDNA and genomic clones corresponding to the novel gene G11 has revealed that the gene spans approximately 9.1 kb of DNA and is split into 7 exons. The 5' end of the gene is associated with a CpG-island while the 3' end of the gene lies 611 bp from the transcriptional start site of the C4A gene. The approximately 1.4 kb G11 mRNA, which is expressed in a number of different cell types including monocytes, hepatocytes, epithelial cells, T and B lymphocytes, encodes protein products of 254 or 258 amino acids due to differential use of two splice sites lying 12 bp apart at the end of exon 3. These polypeptides share homology with a limited number of proteins including human cytochrome P450XIB1 and the tyrosine kinase transforming protein from fujinami virus. Duplication of the C4/P450c21 transcriptional unit occurred by a nonhomologous recombination event. Sequence analysis of a 1.5 kb segment of DNA flanking the C4B gene has revealed that 914 bp of the 3' end of the G11 gene also lies 611 bp from the transcriptional start site of the C4B gene.(ABSTRACT TRUNCATED AT 250 WORDS)

Constrained acetabular components

Between May 1987 and October 1990, 21 constrained acetabular components were used in revision total hip arthroplasty at the University of California, San Francisco. In 18 patients, the device was placed for a chronically dislocating total hip arthroplasty. In the remaining three, intraoperative instability during revision total hip arthroplasty necessitated its use. At the minimum 2-year follow-up evaluation (average, 31 months; range, 24-64 months), 15 patients (71%) experienced no further dislocations or subluxations. There were eight dislocations in the remaining six patients (29%). The average Harris hip score at the follow-up evaluation was 76 points (range, 32-100 points). For those patients who redislocated (n = 6), an increased acetabular abduction angle of the metallic acetabular cup, averaging 70 degrees, was the only predictive factor of failure of the constrained cup (P < .05). No radiographic or clinical evidence of loosening in the 19 porous ingrowth acetabular component was observed. This device will relieve the complication of severe hip instability in the majority of patients, but is not universally successful.

Analysis of sequence contexts flanking T.G mismatches leads to predictions about reactivity of the mismatched T to osmium tetroxide

Osmium tetroxide and hydroxylamine are used to detect mutations in DNA and RNA after hybridization of mutant and wild-type DNA. Mismatched T and C bases, respectively, are modified by these reagents and the DNA strand cleaved at the mismatched bases by subsequent treatment with piperidine. This allows detection and location of the mutation. Although most T.G mismatches have been reported to be reactive to osmium tetroxide, some have been reported to be unreactive. The aim of this study was to collect and analyze the reactive and unreactive T.G mismatches. We have collected sequence contexts of all reactive and unreactive T.G mismatches for analysis. This involves 10 unreactive T.G mismatches (plus one T.C) and 19 reactive T.G mismatches. Sequence effects of bases surrounding these mismatches must influence this reactivity. There must be many types of such sequence effects. We postulate that because of the dominance of 5' G bases near the T of unreactive T.G mismatches and the absence of 5' G bases in reactive T.G mismatches that the stacking of the 5' G on the mismatched T is the reason for this lack of reactivity in the majority of the cases studied here.

GABA-mediated synaptic interaction between the visual and vestibular pathways of Hermissenda

The synaptic convergence of the eyes and the vestibular hair cells in the nudibranch mollusc Hermissenda has been shown previously to mediate the learning of simple visual-vestibular associations. The neurotransmitter mediating this interaction between the visual and vestibular organs was characterized. HPLC chromatography, confirmed by mass spectroscopic analysis, demonstrated endogenous GABA in the statocysts, in a concentration approximately 150 times greater than in the whole CNS. Additional confirmation was provided by immunocytochemical localization of GABA in hair cell axons and branches that converge with photoreceptor terminal branches. Depolarization of the hair cells in the caudal region of the statocyst in response to positive current injection or vibratory stimulation caused a hyperpolarization and a cessation of the type B photoreceptor impulse activity. The inhibition of the B cell was unaffected by addition to the artificial sea water bath of the adrenergic antagonist yohimbine (250 microM), the cholinergic antagonist atropine (250 microM), and the serotonergic antagonist imipramine (50 microM). In contrast, the GABAA antagonist bicuculline (250 microM) significantly reduced the inhibitory interaction. Moreover, the GABA reuptake inhibitor guvisine (250 microM) increased the hyperpolarization. Pressure microapplication of GABA (12.5 or 25 microM) onto the terminal branches of the B cell resulted in a concentration-dependent hyperpolarization and cessation of spikes in the B cell. Depolarization of the caudal hair cell, or direct GABA application, decreased input resistance across the B cell soma membrane. Moreover, removal of chloride from the extracellular solution reduced inhibition of the B cell induced by GABA application or hair cell stimulation. Furthermore, application of the GABAB agonist baclofen hyperpolarized the type B cell and reduced or eliminated spontaneous impulse activity at the resting membrane potential. The reversal potentials for inhibition induced in all three procedures ranged from -70 to -80 mV and were consistent with mixed Cl- and K+ conductances. These results implicate GABA as the endogenous neurotransmitter mediating visual-vestibular interactions in this animal, and suggest a possible role of GABA in visual-vestibular associative learning.

Tumor suppressor genes studied by cell hybridization and chromosome transfer

Although the cloning of tumor suppressor genes has proved to be an arduous task, often involving several years of labor intensive cloning strategies, a greater understanding of neoplastic progression will be made once the function and role of these genes have been sorted out. To fully appreciate the state at which this field of research currently is, however, one must understand that the road to tumor suppression was paved by both somatic cell hybridization and chromosome transfer studies. Although regarded by many as laboratory artifact, somatic cell hybridization has provided strong circumstantial evidence, if not formal proof, for the existence of tumor suppressor genes. In further reducing the complexity associated with whole genome transfer, single chromosome transfer was subsequently developed as a refinement to this technique so that one could unequivocally correlate suppression with a particular chromosome. We have learned from these studies that single chromosomes harbor the genetic information necessary to reverse the malignant phenotype associated with cancer cells. Furthermore, multiple tumor suppressor loci are now known to exist, with one to several different loci associated with a given tumor type. In this review, we present evidence for tumor suppressor genes and discuss the early studies that led to their discovery.

Human parvovirus infection in homozygous sickle cell disease

We studied the epidemiology of human parvovirus B19 infection in 308 children with homozygous sickle cell (SS) disease and 239 controls with a normal haemoglobin (AA) genotype followed from birth in a cohort study. Annual serum samples identified the time and frequency of B19 infection, which did not differ between SS and AA children, about 40% of each group developing specific IgG by age 15. B19 infection followed an epidemic pattern similar to that observed for aplastic crises; accounted for all 91 aplastic crises that occurred; and was found in an additional 23 SS patients, of whom 10 showed mild haematological changes and 13 no changes. The magnitude or duration of IgG response did not differ between these groups. No patient had 2 attacks of aplasia and no patient nor control had 2 attacks of B19 infection. Following B19 infection, serial specific IgG concentrations remained high after 5 years in only 45% of SS patients, although the rarity of recurrent aplasia suggests lifelong immunity. B19 infection accounts for most if not all aplastic crises in SS disease, but at least 20% of infections do not result in aplasia. An effective vaccine against B19 might make an important contribution to the management of sickle cell disease.

Covalent binding properties of the human complement protein C4 and hydrolysis rate of the internal thioester upon activation

The complement proteins C3 and C4 have an internal thioester. Upon activation on the surface of a target cell, the thioester becomes exposed and reactive to surface-bound amino and hydroxyl groups, thus allowing covalent deposition of C3 and C4 on these targets. The two human C4 isotypes, C4A and C4B, which differ by only four amino acids, have different binding specificities. C4A binds more efficiently than C4B to amino groups, and C4B is more effective than C4A in binding to hydroxyl groups. By site-directed mutagenesis, the four residues in a cDNA clone of C4B were modified. The variants were expressed and their binding properties studied. Variants with a histidine residue at position 1106 showed C4B-like binding properties, and those with aspartic acid, alanine, or asparagine at the same position were C4A-like. These results suggest that the histidine is important in catalyzing the reaction of the thioester with water and other hydroxyl group-containing compounds. When substituted with other amino acids, this reaction is not catalyzed and the thioester becomes apparently more reactive with amino groups. This interpretation also predicts that the stability of the thioester in C4A and C4B, upon activation, will be different. We measured the time course of activation and binding of glycine to C4A and C4B. The lag in the binding curve behind the activation curve for C4A is significantly greater than that for C4B. The hydrolysis rates (k0) of the thioester in the activated proteins were estimated to be 0.068 s-1 (t1/2 of 10.3 s) for C4A and 1.08 s-1 (t1/2 of 0.64 s) for C4B. These results indicate that the difference in hydrolysis rate of the thioester accounts, at least in part, for the difference in the binding properties of C4A and C4B.

Comparison of the cytology brush with the Dacron swab for detecting Chlamydia trachomatis by enzyme immunoassay in female university students

Previous studies comparing the cytology brush (Cytobrush) with swabs for the detection of Chlamydia trachomatis from the uterine cervix have yielded divided results. The authors carried out a retrospective analysis at the University of South Florida Student Health Service to evaluate the effect of a change in specimen collection technique on C trachomatis prevalence estimates in female university students. Samples were collected from 1,003 women in 1989, using a small Dacron swab, and 1,229 women in 1990, using a brush; the samples were tested by means of the Pathfinder Enzyme Immunoassay (EIA) detection kit. Positive test results were 5.88% for 1989 and 11.66% for 1990. Actual C trachomatis prevalence for 1989 and 1990 was stable, as determined by three control groups. The results suggest that the cytology brush is more effective than the Dacron swab for the detection of C trachomatis in the uterine cervix when it is used with the Pathfinder EIA test kit.

Effect of undocumented and excluded vaccinations on measles immunity in a university population

Epidemic measles has occurred even in highly vaccinated university and college populations because vaccine efficacy is only 90-95% and some student bodies do not have 100% vaccine coverage. Some institutions have not adopted or enforced a one-dose, preregistration immunization requirement because of the increased administrative burden, although in 1990 a documented two-dose schedule was recommended to increase herd immunity to a critical 93.5-96.0%. Perhaps one documented immunization for all students coupled with an undocumented or excluded pre-1968 one that some students are reporting will result in adequate herd immunity. At the University of South Florida 149 students (group I), after documenting receipt of one immunization, attempted to prove immunity by having an antibody test. They were compared with 181 students who documented two doses (group II) for factors which might influence differences of immunity between the groups after one dose. Undocumented immunizations were estimated by determining the percent of students reporting recent immunizations after allowing for the expected unimmunized percent. Excluded vaccinations were calculated for students born before 1967. Group I had a 98% (95% C.I. 94.2-99.6) immunity. One-third to one-half of both groups had undocumented and excluded immunizations. Some differences identified were not important enough to prevent extrapolation of this high immunity from group I to group II students. One documented live measles vaccination for all students combined with an undocumented or excluded one for some of them may provide adequate herd immunity to prevent measles epidemics on university and college campuses.

Differences in growth of neurons from normal and regenerated teleost spinal cord in vitro

Explants and dissociated cells from normal adult spinal cord and regenerating cord of the teleost Apteronotus albifrons were grown in vitro for periods of 8 to 12 wk. During this time the neurons showed extensive neurite outgrowth. Neurite outgrowth from tissue explants and dissociated cells of regenerated spinal cord starts sooner and is more profuse than that from normal (unregenerated) cord. Neurite outgrowth is maximized by using adhesive substrata and a high density of explants or dissociated cells. Inasmuch as Apteronotus does regenerate its spinal cord naturally after injury, whereas mammals do not, this culture system will be useful to study factors that control (permit) regeneration of spinal neurons in this adult vertebrate.