In vivo effects of cardiotrophin-1

Cardiotrophin-1 (CT-1) is a recently discovered cytokine that was isolated based on its ability to induce cardiac myocyte hypertrophy in vitro. In this study, the effects of chronic administration of CT-1 to mice (0.5 or 2 microg by intraperitoneal injection, twice a day for 14 days) were determined. A dose-dependent increase in both the heart weight and ventricular weight to body ratios was observed in the treated groups. The body weights of the animals were unaffected. These results indicate that CT-1 can induce cardiac hypertrophy in vivo. CT-1 was not specific for the heart, however. It stimulated the growth of the liver, kidney, and spleen, and caused atrophy of the thymus. CT-1 administration also increased the platelet counts by 70%, with no change in mean platelet volume. Red blood cell counts were increased in the treated animals, and there was a concomitant increase in haemoglobin concentration. Thus, CT-1 has a broad spectrum of biological activities in vivo. This observation is consistent with previous in-vitro findings showing that the mRNA for CT-1 is expressed in several tissues, and that CT-1 can function through binding to the leukaemia inhibitory factor (LIF) receptor and signalling through the gp130 pathway.

Positional cloning of genes involved in the Beckwith-Wiedemann syndrome, hemihypertrophy, and associated childhood tumors

The Beckwith-Wiedemann syndrome (BWS) is an overgrowth malformation syndrome that occurs with an incidence of 1:13,700 births. There is a striking incidence of childhood tumors found in BWS patients. Various lines of investigation have localized "imprinted" genes involved in BWS and associated childhood tumors to 11p15. High resolution mapping of 8 rare balanced chromosomal BWS rearrangements enabled us to identify three distinct regions on chromosome 11p15 that might harbor genes involved in the above-mentioned disorders. These results suggest genetic heterogeneity that correlates with the clinical heterogeneity seen in the patients studied. Expressed candidate gene sequences from these regions have been cloned and partly sequenced. These transcripts are either disrupted by or are at least within a few kb of these BWS chromosome breakpoints. So far, zinc-finger sequences and one Kruppel-associated box (KRAB) domain were found in independent candidate genes which are compatible with a regulating function of growth promoting genes. The abundance of expression of these genes varies from low abundant in all adult and fetal tissues tested to detectable on Northern blots of adult tissues. In addition to our 11p15 studies we have analyzed additional chromosome regions, in particular 1p. Cytogenetic, loss of heterozygosity (LOH) and comparative genomic hybridization (CGH) studies have identified 1p35 as a region of interest. A positional cloning effort to identify a balanced 1p35 translocation found in a Wilms tumor has led to the isolation of a YAC, crossing this breakpoint.

Pharmacokinetics, tissue distribution, and expression efficiency of plasmid [33P]DNA following intravenous administration of DNA/cationic lipid complexes in mice: use of a novel radionuclide approach

The pharmacokinetics, tissue distribution, and efficacy of a systemic gene transfer method were examined in male BALB/c mice (6-8 weeks old) using 33P-labeled plasmid DNA for luciferase. The DNA was delivered via tail vein injection in saline ([33P]DNA) or in a cationic lipid formulation ([33P]DNA/lipid). One group of mice received approximately equal to 1-3 microCi (45 micrograms of DNA) of either formulation, and mice were euthanized at 2 and 20 min, and 1 and 24 h postdose (2 mice/time point). Blood and plasma radioactivity were quantified, and whole body autoradiographic (WBAR) images were obtained from 20-microns whole body sections. A tissue distribution (TD) study was conducted in a second group of mice, which received approximately equal to 4-6 microCi (45-60 micrograms of DNA) of [33P]DNA/lipid. Mice were euthanized at 1.5 h (1 mouse; [33P]DNA/lipid) or 24 h (2 mice/ group), and organ radioactivity and luciferase expression were measured in lung, liver, kidney, spleen thymus, and parotid salivary gland by direct quantitation methods. Microautoradiography (MAR) was performed on a third group of mice (n = 2), which received 3 microCi (45 micrograms of DNA) of [33P]DNA/lipid and were euthanized at 24 h postdose. For WBAR, the [33P]DNA/lipid tissue distribution (% dose equiv/g) at 2 min was lung >> liver > spleen (red pulp) > kidney (cortex); at 24 h the ranking was spleen (red pulp) > liver > lung, kidney (cortex). The [33P]DNA organ distribution observed at 2 min was liver >> spleen (red pulp) > lung, blood > kidney (cortex); at 24 h the ranking was liver, spleen (red pulp) > kidney (cortex) > lung, blood. High levels of radioactivity in bone (cortical, marrow, growth plate) in both groups may represent uptake of the 33P-labeled test articles by the cellular component of the bone marrow, particularly macrophages, as well as deposition of [33P]phosphate in the bone matrix following metabolism of the [33P]DNA. In the luciferase component of the study, no expression was observed in the [33P]DNA group at 24 h. The [33P]- DNA/lip group exhibited expression as early as 1.5 h in the lung; at 24 h, expression was seen in all the organs examined. Microautoradiography of 24-h tissue samples revealed radioactivity in hepatic Kupffer cells, reticuloendothelial system cells in the marginal zone of the spleen, and diffusely along alveolar septae with scattered accumulations in alveolar macrophages. The results of the WBAR, TD, MAR, and luciferase assay show that the use of cationic lipids significantly altered the biodistribution and resulting expression of the DNA plasmid. Further, 33P (0.25 MeV beta, half-life = 25 days) was shown to be an excellent radionuclide for quantitative WBA and MAR, providing sharp images with less personal hazard and greater ease of handling than 32P (1.71 MeV beta, half-life = 14.3 days).

Altered circadian rhythmicity in the Wocko mouse, a hyperactive transgenic mutant

Induced changes in the level of daily activity can alter the period of the mammalian circadian clock. In this report, we examined the period of the circadian rhythm of wheel-running activity in a transgenic neurological mouse mutant, Wocko. Wocko mice display a dominant behavioral phenotype that consists of hyperactivity, circling and head tossing. The period of the circadian rhythm of wheel-running activity in constant dark conditions was significantly shorter in mice expressing the Wocko mutation than in their normal littermates. Total activity, monitored by the interruption of an array of infrared beams, was significantly elevated in Wocko mice. These findings support the view that spontaneous exercise can modulate the circadian timekeeping system.

Physiological regulation of early and late stages of megakaryocytopoiesis by thrombopoietin

Thrombopoietin (TPO) has recently been cloned and shown to regulate megakaryocyte and platelet production by activating the cytokine receptor c-mpl. To determine whether TPO is the only ligand for c-mpl and the major regulator of megakaryocytopoiesis, TPO deficient mice were generated by gene targeting. TPO-/- mice have a >80% decrease in their platelets and megakaryocytes but have normal levels of all the other hematopoietic cell types. A gene dosage effect observed in heterozygous mice suggests that the TPO gene is constitutively expressed and that the circulating TPO level is directly regulated by the platelet mass. Bone marrow from TPO-/- mice have decreased numbers of megakaryocyte-committed progenitors as well as lower ploidy in the megakaryocytes that are present. These results demonstrate that TPO alone is the major physiological regulator of both proliferation and differentiation of hematopoietic progenitor cells into mature megakaryocytes but that TPO is not critical to the final step of platelet production.

Automated interstudy image registration technique for SPECT and PET

We report the extended application of an automated computer technique for three-dimensional spatial registration of SPECT and PET studies.

METHODS

The technique iteratively reslices a misaligned data set until the sum of the absolute differences (SAD) from a reference data set is minimized. The registration accuracy was assessed in Hoffman brain phantom studies collected with known misalignments and transmission studies of a thorax phantom with fiducial markers. The SAD was compared with three other cost functions: stochastic sign change criterion, sum of products and standard deviation (s.d.) of ratios. In clinical neurological and myocardial perfusion studies, registration accuracy was estimated from the relative locations of landmarks in the reference and registered data sets.

RESULTS

Registration accuracy in the Hoffman brain phantom studies was -0.07 +/- 0.46 mm (mean +/- s.d.) for translations and -0.01 +/- 0.20 degrees for rotations, with maximum translation and rotation errors of 1.2 mm and 0.8 degree, respectively. The SAD was the most accurate and reliable cost function. Registration errors in the thorax phantom were 3.1 +/- 1.7 mm. Mean accuracy in the neurological studies, estimated from landmark pairs, was 2.0 +/- 1.1 mm for SPECT to SPECT and 1.8 +/- 1.1 mm for PET to SPECT registrations. Average registration accuracy in 201Tl myocardial perfusion studies was 2.1 +/- 1.2 mm.

CONCLUSION

Our registration method (a) provided accurate registrations for phantom and clinical SPECT and PET studies, (b) is fully automated, (c) simplifies comparison of data sets obtained at different times and with different modalities, and (d) can be applied retrospectively.

Transgenic knockouts reveal a critical requirement for pancreatic beta cell glucokinase in maintaining glucose homeostasis

The secretion of insulin is controlled by the rate of glucose metabolism in the pancreatic beta cells. As phosphorylation by glucokinase (GLK) appears to be the rate-limiting step for glucose catabolism in beta cells, this enzyme may be the glucose sensor. To test this possibility and to resolve the relative roles of liver and beta cell GLK in maintaining glucose levels, we have generated mice completely deficient in GLK and transgenic mice in which GLK is expressed only in beta cells. In mice with only one GLK allele, blood glucose levels are elevated and insulin secretion is reduced. GLK-deficient mice die perinatally with severe hyperglycemia. Expression of GLK in beta cells in the absence of expression in the liver is sufficient for survival. These mice demonstrate the critical need for beta cell GLK in maintaining normal glucose levels and provide a novel model for one form of noninsulin-dependent diabetes.

Ligand-independent repression by the thyroid hormone receptor mediated by a nuclear receptor co-repressor

Thyroid-hormone and retinoic-acid receptors exert their regulatory functions by acting as both activators and repressors of gene expression. A nuclear receptor co-repressor (N-CoR) of relative molecular mass 270K has been identified which mediates ligand-independent inhibition of gene transcription by these receptors, suggesting that the molecular mechanisms of repression by thyroid-hormone and retinoic-acid receptors are analogous to the co-repressor-dependent transcriptional inhibitory mechanisms of yeast and Drosophila.

Inactivation of the mouse Huntington's disease gene homolog Hdh

Huntington's disease (HD) is a dominant neurodegenerative disorder caused by expansion of a CAG repeat in the gene encoding huntingtin, a protein of unknown function. To distinguish between "loss of function" and "gain of function" models of HD, the murine HD homolog Hdh was inactivated by gene targeting. Mice heterozygous for Hdh inactivation were phenotypically normal, whereas homozygosity resulted in embryonic death. Homozygotes displayed abnormal gastrulation at embryonic day 7.5 and were resorbing by day 8.5. Thus, huntingtin is critical early in embryonic development, before the emergence of the nervous system. That Hdh inactivation does not mimic adult HD neuropathology suggests that the human disease involves a gain of function.

An evaluation of changes in composition and contamination of salvaged blood from the cardiopulmonary bypass circuit of pediatric patients

OBJECTIVE

To review changes that occur during an 18-hour period in composition and bacterial contamination of blood salvaged from the cardiopulmonary bypass (CPB) circuit of pediatric patients.

DESIGN

Prospective, blinded study.

SETTING

Pediatric tertiary multidisciplinary intensive care unit.

PATIENTS

One hundred and one children who underwent CPB.

OUTCOME MEASURES

The degree of bacterial contamination and biochemical and hematologic alterations of blood salvaged from the CPB and any increased blood loss associated with reinfusion of this blood.

INTERVENTION

The salvaged blood from the CPB circuit was collected into 1 L blood transfer packs after CPB. This blood was then stored at room temperature for 18 hours. Sampling occurred immediately after CPB and at 6 and 18 hours for biochemic and hematologic assay and for the detection of bacterial organisms. The amount of chest drainage loss was assessed in the first 18 hours after bypass. The type and amount of intravenous fluid infused also was recorded.

RESULTS

Bacterial contamination occurred in three samples (two at 6 hours and in one of the preceding at 18 hours) of the 101 units of salvaged blood. All three positive cultures grew a coagulase-negative staphylococcus. Sodium and potassium remained within normal physiologic values. The glucose values declined from 15.8 to 13.4 mmol/L, and the hemoglobin values increased from 0.4 to 0.5 gm/dl. The reinfusion of the salvaged blood (and any other blood or blood products) to 31 of the 101 patients averaged 14.2 ml/kg/24 hr, with a mean chest drainage loss of 4.9 ml/kg/24 hr. The remaining 70 patients received 12.5 ml/kg/hr of either plasma expanders or blood, with a mean chest drainage loss of 6.0 ml/kg/24 hr.

CONCLUSIONS

The results of this study demonstrate minimal chemical deterioration and limited microbiologic contamination in blood that was salvaged from the CPB circuit and stored at room temperature for an 18-hour period. No increase in postoperative bleeding was noted from the use of this blood. These results suggest it may be safe to reinfuse salvaged blood after CPB in pediatric patients for up to 18 hours; however, a prospective clinical trial is needed to validate these findings.

The changing epidemiology of invasive meningococcal disease in Canada, 1985 through 1992. Emergence of a virulent clone of Neisseria meningitidis

OBJECTIVE

To describe the occurrence of invasive meningococcal disease (IMD) in Canada with respect to demographic variables and characteristics of the isolated strains of Neisseria meningitidis.

DESIGN

National surveillance case series.

SETTING

Canada, 1985 through 1992.

OUTCOME MEASURES

Morbidity and mortality.

MAIN RESULTS

The incidence of IMD averaged 1.38 per 100,000 person-years, with considerable regional variation. In 1988, serogroup C organisms became more common, with one strain of the electrophoretic type 37 (ET-37) complex of N meningitidis, termed ET-15, the predominant group C strain identified. With the increase in group C disease, a greater proportion of cases were older than 5 years. By 1991, ET-15 was the most common strain identified in most parts of the country. Electrophoretic type 15 had a case fatality of 17.8% vs 8.1% for all other IMD (P < .001). Among cases 20 years and older the case fatality for ET-15 was 22.4%.

CONCLUSIONS

The group C, ET-15 strain of N meningitidis, first identified in Canada, was more virulent than other prevalent strains during this period. Active surveillance, rapid identification, and typing of N meningitidis will assist public health decision making in the control of emerging strains.

Epidermal growth factor and basic fibroblast growth factor are induced in guinea-pig tympanic membrane following traumatic perforation

Epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF or FGF-2) have been shown to enhance the healing of traumatic tympanic membrane (TM) perforations. The action of EGF and bFGF in the TM repair process remains unknown. This study was designed to determine the expression of EGF and bFGF in normal and injured TM by immunohistochemistry. EGF was detected in normal TM mainly in the annulus tympani area. After a perforation in the TM posterior/superior quadrant, EGF was detected around the perforated area in polynuclear cells, in pericytes and in basal epithelial cells. EGF was also detected in the antero/superior quadrant in basal epithelial cells and pericytes. The peak of EGF detection was observed 3 days after the perforation. bFGF was not detected in normal TM, but it was expressed 3 days after a traumatic perforation mainly in the perforated area in pericytes and in polynuclear cells. This study suggests that EGF and bFGF are involved in the control of TM acute perforation repair. These findings help to explain the accelerated healing of TM perforations that are seen after application of FGF or EGF, and suggest that antibodies against these growth factors would retard the healing process.

Neutralizing antibodies against basic fibroblast growth factor influence the healing of traumatic tympanic membrane perforations

The beneficial effects of basic fibroblast growth factor (bFGF or FGF-2) in healing of tympanic membrane (TM) perforations have been demonstrated in animal models, and this study was conducted to investigate the effect of neutralizing anti-FGF-2 antibodies on acute tympanic membrane perforation healing. Anti-FGF-2 rabbit polyclonal antibodies were applied to traumatic TM perforations in guinea-pigs on days 0, 1, 2 and 3, whilst the opposite ear was treated with normal rabbit serum. On day 4, the perforation area was assessed, and the histological structure of the scar was studied. The average opening was larger in the neutralizing anti-bFGF-treated group, but the difference was not statistically significant. Histological analysis showed that scars treated with neutralizing anti-bFGF contained significantly less epithelial cells and less mononuclear cells. They also contained less fibroblasts and less vessels, but this difference was not significant. These data suggest that FGF-2 is one of the factors involved in the control of epithelial cells proliferation and mononuclear cell invasion in the initial phase of TM perforation healing. Neutralizing anti-bFGF antibodies could be of use in reducing the inflammation during the healing of TM perforations or to create animal models of chronic tympanic membrane perforations.

Meningococcal infections in the Province of Québec, Canada, during the period 1991 to 1992

A total of 234 strains of Neisseria meningitidis obtained from hospitalized patients living in the province of Québec during the period 1991 to 1992 were characterized according to their serogroup, serotype, subtype, electrophoretic type, and antimicrobial susceptibility. All these strains were recovered from sterile body fluids, except for one strain that was isolated postmortem from a cutaneous lesion. For both years, serogroup C was the most prevalent (69.7%), followed by serogroup B (27.4%). Serotype 2a represented 80.3% of serogroup C isolates, and P1.2 was the most common subtype associated with this serotype. Clone ET 15 accounted for 76.5% of serogroup C isolates and 90.0% of serotype 2a strains. Although meningococcal disease occurred mostly in children under the age of 5 (9.7 cases per 100,000 children), with a peak incidence for children under 1 (20.3 cases per 100,000 children), most fatalities occurred among teenagers (12 to 19 years old). The total fatality rate was 11.5%, and serogroup C strains were responsible for 88.9% of these fatalities. Thirteen strains had a reduced susceptibility to penicillin G, and 28 strains were resistant to sulfadiazine. One strain was resistant to both rifampin and sulfadiazine and showed a reduced susceptibility to penicillin G.

Expression of mRNAs encoding alpha and beta subunit isoforms of Na,K-ATPase in the vestibular labyrinth and endolymphatic sac of the rat

The distribution of mRNAs coding for three different isoforms of the alpha and two of the beta subunit of Na,K-ATPase was studied in the rat vestibular system using in situ mRNA hybridization. The dark cells of the utricular macula and of the ampullae of the semicircular canals expressed high levels of mRNA encoding the alpha 1 and beta 2 isoforms of the Na,K-ATPase, a composition that in the cochlea has been uniquely found in the stria vascularis. However, in the dark cells it was coupled with a weak expression of beta 1. The sensory epithelia of the vestibular system showed alpha 1 and beta 1 expression at much higher levels than in the cochlear sensory epithelium. Weak expression limited to the alpha 1, beta 1, and beta 2 isoforms was observed in the endolymphatic sac, contrasting previous cytochemical results which suggested extensive Na,K-ATPase activity to the sac. The results support the widely held hypothesis that the vestibular dark cells play a role similar to that of the stria vascularis in endolymph production. They indicate that the ion transport requirements of the vestibular sensory epithelia may be different than those in the cochlea. They also suggest that the endolymphatic sac may not be a major site of inner ear ion exchange.

Effect of basic fibroblast growth factor on normal tympanic membrane

PURPOSE

Basic fibroblast growth factor (bFGF) is mitogenic for the cell types that constitute the tympanic membrane and has been shown to potentiate tympanic membrane healing. The purpose of this study is to investigate the direct effect of bFGF application on normal tympanic membrane.

MATERIALS AND METHODS

bFGF was applied to the normal tympanic membrane of 10 guinea pigs via either the external auditory external canal or the middle ear. The drug (400 ng) was delivered on days 0, 1, and 2. The contralateral ear was used as a control. The effects were assessed on day 3.

RESULTS

The cumulative area and the average area of blood vessel in each session of TM was greater after bFGF application than placebo. The number of vessels remained unchanged. A proliferation of keratinocytes was observed.

CONCLUSION

These results suggest that bFGF induces a vasodilatation in the tympanic membrane thereby increasing blood supply. This might explain the acceleration of healing of TM perforations after bFGF application.

Improving discharge planning

In ward 9 of the Nursing Development Unit at Whiteabbey Hospital, Newtonabbey, Northern Ireland, developments and innovations are channelled through the use of working groups which are essentially the pivot on which the unit rotates. This article details the activities of one of these groups, the discharge planning group.

Direct application of basic fibroblast growth factor improves tympanic membrane perforation healing

Topical application of basic fibroblast growth factor (b-FGF) on tympanic membrane (TM) perforations was studied in guinea pigs. One-millimeter simple round TM perforations or 2-mm TM perforations with medially flapped borders were performed. Either b-FGF or placebo was instilled in each ear on the day of surgery and daily thereafter. Treatment was applied either directly to the perforation or to a Gelfoam pledget over the defect. When no scaffolding material was interposed, b-FGF induced a faster healing response characterized by a hyperplastic but linear subepidermal connective tissue reaction compared to the control. When Gelfoam was interposed as a scaffold, a voluminous scar protruding into the middle ear cavity and involving the ossicles was observed in both b-FGF and control animals. Gelfoam-induced scars did not decrease after long-term observation, therefore discouraging its use.

Chicken sterol carrier protein 2/sterol carrier protein x: cDNA cloning reveals evolutionary conservation of structure and regulated expression

The chicken is a useful model for studies of lipid biochemistry because of the profound changes in lipid metabolism during development and the marked effects of estrogen on its lipids. Here we report the cloning of a cDNA encoding chicken sterol carrier protein 2 (SCP2)/sterol carrier protein x (SCPx), proteins that are believed to play key roles in intracellular lipid movement and metabolism. The 2.4-kb clone, isolated from a liver cDNA library by homology screening with a rat SCP2 cDNA, encodes a 58-kDa polypeptide, SCPx, which encompasses the sequence for SCP2 at its C-terminus. Comparison of the deduced amino acid sequence of the chicken protein with those of mammals revealed conservation of structure from an evolutionary standpoint. Like the other vertebrate SCPx proteins, the chicken protein contains a conserved Arg-Gly-Asp sequence and a cysteine residue in the N-terminus that aligns with the active site cysteine of Escherichia coli 3-ketoacyl-CoA thiolase, a protein that was previously shown to be homologous to vertebrate SCPx. Northern blot analysis of poly(A)+ RNA from different chicken tissues revealed two mRNA species, one of 2.5 kb, encoding SCPx, and one of 1.4 kb, presumably encoding SCP2. High levels of the 2.5 and 1.4-kb mRNAs were found in liver, intestine, and ovarian granulosa cells, consistent with a role for these proteins in lipid metabolism. There was no change in the 2.5-kb mRNA in chicken liver with development (Day 20 embryo to 4 weeks posthatch), but there was a 10-fold increase in the 1.4-kb mRNA by 1 week posthatch. Treatment of roosters with a single injection of estradiol (25 mg/kg) caused a twofold increase in the 2.5-kb mRNA in liver at 6 h after estradiol administration, reaching a maximum fourfold increase at 48 h, while the 1.4-kb mRNA increased twofold at 48 h. The two SCP2/SCPx mRNAs were most abundant in granulosa cells from small follicles. A reduction in SCP2/SCPx gene expression was observed with follicular maturation, correlating with falling estrogen production. In summary, we have documented (i) marked conservation of SCP2/SCPx structure across species and (ii) developmental and hormonal regulation of the mRNAs which encode proteins thought to be involved in lipid metabolism.

Elevated lead levels in reportedly abused children

Children suspected of having been physically abused had significantly higher venous blood lead levels than a comparison group (p < 0.0001). Abused children were 27-fold more likely to have lead levels > 0.965 mumol/L (20 micrograms/dl) (odds ratio = 26.7). We recommend that abused children be monitored for lead intoxication more frequently than other children.

Histological study of the healing of traumatic tympanic membrane perforation after basic fibroblast growth factor application

Basic fibroblast growth factor (bFGF) can stimulate the proliferation and differentiation of keratinocytes, fibroblasts, and endothelial cells. These cells are involved during the healing of tympanic membrane (TM) perforations. Light and electron microscopy examinations were used to study the histology of TM healing after application of 400 ng of bFGF on the perforation. The progress of healing is accelerated, but the basic healing process is unchanged, i.e., epithelial proliferation first closes the perforation and is then followed by connective tissue growth. There is more connective tissue in the TM receiving bFGF, and extracellular fibers are better oriented. No significant increase of neoangiogenesis was detected in the treated TM. In the nonperforated area of treated TM, an extensive hyperplasia of the submucosal connective tissue is observed. These results demonstrate that bFGF can produce a TM scar containing more connective tissue, which may be of benefit in the prevention of atrophic healed TM.

Carriage of Neisseria species in communities with different rates of meningococcal disease

A single clone, Neisseria meningitidis serogroup C (C:2a:P1.2), was isolated from seven patients during a cluster of cases of meningococcal disease in Ontario in 1989. To determine whether the clone was present in asymptomatic individuals in the same population, pharyngeal swabs were taken from 7% (644 of 9125) of residents who were vaccinated during the outbreak. Rates of isolation of Neisseria species were also compared to those in two other geographical areas which did not have an elevated incidence of meningococcal disease. The rate of carriage of N meningitidis in the asymptomatic individuals sampled was between 1.9% and 5.4%. The clone isolated from patients was not present among the carrier strains as determined by sero- and subtyping and electrophoretic analysis of metabolic enzymes. Age greater than six years was the only factor associated with colonization with N meningitidis.

Wocko, a neurological mutant generated in a transgenic mouse pedigree

Naturally occurring mutations involving the nervous system have provided virtually all of our current understanding of the genetic regulation of neural development (Caviness and Rakic, 1978). The difficulty of isolating the corresponding genes, however, has precluded a molecular analysis of these mutants. Insertional mutagenesis, induced by microinjection of DNA into fertilized ova to produce transgenic animals, provides a molecular tag that marks the site of the mutational event. In this article, we describe a transgenic neurological mutation, designated wocko (Wo), which disrupts the development of the inner ear. These mutant mice display a dominant behavioral phenotype that consists of circling, hyperactivity, and head tossing, reminiscent of the shaker/waltzer class of mutants, and they display a recessive homozygous sublethal phenotype. Anatomical analyses showed that both structural and neural components of the vestibular system were disrupted, while analyses of mutant fetuses showed that these morphological abnormalities were due to aberrant development. Although low levels of transgene expression were detected using a sensitive PCR assay, several nonmutant pedigrees that contain the same construct also expressed the transgene in the inner ear, suggesting that low levels of transgene expression alone were not responsible for the wocko phenotype. Because the integrated transgene provides a marker to clone the wocko mutation, the analysis of this mutant will give unique insight into the molecular genetics of inner ear development and into a broad class of neurological mutations that affect the inner ear.

The response to human rIL-1, rIL-2, and rTNF in the middle ear of guinea pigs

Human recombinant interleukin 1 (rIL-1), interleukin 2 (rIL-2), or tumor necrosis factor (rTNF) were injected transtympanically into the middle ear of normal guinea pigs. Effusion volume and cellular content were determined after sacrifice and rapid dissection of the ear. By 24 hours, rIL-2 (100 U) had produced a cellular effusion (77% to 92% polymorphonuclear neutrophil leukocytes), which cleared by 72 hours. rTNF (10 U) yielded a cellular effusion (12% to 67% lymphocytes) at 24 hours, which cleared by 48 hours. rIL-1 (100 U) did not produce significant effusion when compared to control. rIL-2 and rTNF cause an inflammatory effusion in the middle ear. To the extent they are generated in the middle ear during otitis media, these cytokines have the potential to contribute to the pathogenesis of otitis media with effusion.

Improved healing of tympanic membrane perforations with basic fibroblast growth factor

We have investigated the effects of basic fibroblast growth factor (FGF) on the healing of tympanic membrane (TM) perforations. In the first series of experiments, a simple, round 1-mm perforation was made in the membrane and the effects of basic FGF examined. In a second series of experiments, basic FGF was tested on 2-mm perforations in which the borders were folded inward in order to delay normal healing. Topical applications of saline or basic FGF were administered onto gelfoam overlays of the TM perforations in 51 guinea pigs by delivering 5 microliters aliquots of PBS or 5 microliters of PBS containing 1 microgram of basic FGF on the day of surgery and daily thereafter. Repair of the lesions was evaluated 3, 5 or 8 days after surgery. The results show that basic FGF mediates faster healing of TM perforations by inducing rapid proliferation of the subepithelial connective tissue layer.

Identification of a cell-surface antigen associated with activated T lymphoblasts and activated platelets

We have identified and biochemically characterized an antigen, 8A3, which is expressed on activated T lymphoblasts and activated platelets. Monoclonal antibodies to 8A3 were raised against the primitive lymphoid/myeloid cell line KG1a and additionally bound to the erythroleukemia-derived cell line HEL, whilst exhibiting little or no reactivity with a panel of other hematopoietic cell lines. The 8A3 antigen was expressed on poorly differentiated T-cell leukemias and on phytohemagglutinin-activated T-cells maintained in interleukin-2 (7,000 sites/cell). This antigen, though not detected on resting platelets, was expressed on thrombin-activated platelets (2,000 sites/platelet). Antibodies to 8A3 identified polypeptides of Mr 170,000 and 150,000 in lysates of surface-iodinated KG1a cells, T lymphoblasts, and activated platelets under both reducing and nonreducing conditions. However, peptide mapping and susceptibily to glycosidases indicated that the 8A3 antigen was a monomeric glycoprotein of Mr 170,000 which contained two N-linked endoglycosidase H-sensitive glycans, and that the Mr 150,000 structure was derived from it by proteolytic degradation. The 8A3 antigen was not detectably phosphorylated in KG1a cells in vivo, nor did immune complexes containing it exhibit kinase activity in vitro. Structural and serologic characteristics of the 8A3 antigen indicate that it is different from other previously described leukocyte activation antigens including transferrin receptors, interleukin-2 receptors, members of the integrin family of adhesion molecules, or "restricted" members of the leukocyte-common antigen/CD45 cluster. Furthermore, the 8A3 antigen does not appear to be related to the other previously described activation-specific platelet molecule, GMP140/PADGEM. This antibody may be useful in monitoring T-cell activation status in some clinical situations and in characterizing clinically relevant activation-associated platelet membrane alterations.

A waterborne outbreak of leptospirosis among United States military personnel in Okinawa, Japan

A waterborne outbreak of leptospirosis occurred among US military personnel during September 1987, on the island of Okinawa, Japan. Micro-agglutination titres for leptospiral antigen of greater than or equal to 200 were detected in hospitalized adult males averaging 22.5 years of age with symptoms compatible with leptospirosis. Epidemiological findings revealed two case clusters distinguished by time and place of exposure. The overall attack rates among recreational swimmers and combat skills training participants were 467/1000 (7/15) and 183/1000 (15/82), respectively. Swallowing of water differentiated individuals with laboratory-confirmed infection from those with no infection, while water immersion alone did not appear to result in leptospiral infection. Additionally, subnormal rainfall may have contributed to the risk of exposure associated with this outbreak.

Neural tube defects in rural Ireland

The incidence of neural tube defects in a rural area of the west of Ireland from 1974 to 1985 was 2.96 per 1000. The prevalence was unchanged during the 11 years. When compared with a control group there was no increased incidence of anaemia in mothers of affected infants.

The early postnatal development of the cochlear vasculature in the gerbil

The blood vessels of the cochlea were studied from birth up to adult age in the gerbil. Even at birth the principal vascular arrangement could be identified in the external wall. However, the early circulatory mainstream appeared even more predominantly radial apico-basal over radiating arterioles-arteriovenous anastomoses-collecting venules than at later stages. At birth, only small sections of capillaries could be observed in the stria vascularis. Stria vascularis achieved its adult vascular appearance rapidly between 8-10 days after birth (DAB). The rapid development of stria vascularis immediately preceded the development of cochlear function and may have been related to the development of the ionic composition of endolymph. At birth the vessel of the basilar membrane showed many large vascular connections with the collecting venules in the scala tympani of the external wall but very few supplying and draining ramifications on the medial side of the vessel. This suggests that the vessel of the basilar membrane originates from the external wall vessels, not from the spiral lamina vessels as has previously been supposed. The peripheral vascular connections degenerated rapidly after birth. The vessel, being very large at birth, degenerated completely by 15 to 20 DAB, ultimately disappearing in the basal turn. The degeneration suggests that its major importance may be during embryonic stages, with great probability for the development of the organ of Corti.

Protection against infection with Neisseria meningitidis group B serotype 2b by passive immunization with serotype-specific monoclonal antibody

Hybridomas derived from mice immunized with Neisseria meningitidis serogroup B serotype 2b (B,2b) outer membrane preparations produced monoclonal antibodies (MAbs) specific for major outer membrane proteins of classes 1, 2, and 5. The MAbs were examined by enzyme-linked immunosorbent assay against a selected panel of seven strains of N. meningitidis (B,2b) of different sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns, a serotype 2a, and a nontypable strain. The five MAbs selected were all bactericidal and of different immunoglobulin subclasses. None of the MAbs reacted with other bacterial strains in a dot-enzyme immunoassay. The corresponding antigenic determinant for each MAb was localized on a specific outer membrane protein by immunoblotting of sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns of major outer membrane proteins. MAbs M5-11 and M5-30 bound to the class 2 protein and were serotype 2b specific. MAb M2-20 bound to the class 1 protein, and MAbs M5-16 and M5-19 bound to the class 5 protein. A mouse model of infection was established whereby a local infection progressed to lethal bacteremia over 3 days, and 50% of the animals were killed with an intraperitoneal injection of 10 meningococci plus 4% mucin and 1.6% hemoglobin. The ability of the MAbs to provide passive protection against experimental infection with N. meningitidis (B,2b) was examined. Both serotype-specific MAbs M5-11 and M5-30 were highly protective even though they were of different immunoglobulin subclasses. The class 5-specific MAb offered no protection, while the class 1-specific MAb gave limited protection. It may therefore be possible to provide protection against serotype 2b infection by using as vaccine the class 2 serotype-specific surface-exposed outer membrane protein epitopes defined by MAb M5-11 or M5-30.

Evaluation of a rapid method for the detection of streptococcal group A antigen directly from throat swabs

Throat swabs from 196 pediatric patients were processed by a direct extraction-latex agglutination method (Group A Strep Direct Antigen Identification Test [DAI]) that detects group A streptococci in the specimen. The method requires a 45-min enzymatic extraction period at 37 degrees C and a 4-min reaction period with antibody-linked latex particles. The results were compared with those of the culture and fluorescent antibody methods and the clinical presentation of the patient for pharyngitis. Ninety-three percent of the specimens resulted in agreement by all tests, and 28% were culture positive for group A streptococci. Compared with the culture method, the DAI had a sensitivity and a specificity of 83% and 99%, respectively. The positive predictive values were 98% versus the culture method and 93% versus the fluorescent antibody method, whereas the negative predictive values were 94% versus both other methods. Of the 14 discrepant results when both clinical presentation of an acute pharyngitis and the test results were compared, the culture method provided the best correlation. An additional 64 specimens were processed by the DAI and another direct extraction-latex agglutination method (Culturette Ten-Minute Group A Strep ID Test), and the results were compared with those of the culture method. This group had a 40.6% culture isolation rate for group A streptococci. The sensitivity and specificity of the DAI and Strep ID methods versus the culture method were 81 and 100%, and 77 and 97%, respectively. These results indicate that the DAI is accurate for diagnosing group A streptococcal pharyngitis directly from throat swabs. However, negative results in the presence of a symptomatic patient must be confirmed by standard culture techniques.

Serotype distribution of meningococci isolated in South Australia 1971 through 1980

The serotypes of meningococci isolated from 76 sporadic cases of meningococcal disease in South Australia during the years 1971 through 1980 were determined. Thirty-four (56%) of the 61 group B strains were nontypable; the remainder were of five serotypes namely 8 (16%), 1 (13%), 2 (2a and 2b) (9%), 12 (3%), and 15 (3%). Four of the five group B type 2 strains were serotype 2b. Serotype 2a accounted for four of seven group C strains and four of five group W135 strains. Overall serotypes 2 (2a and 2b) (17%), 8 (13%), and 1 (10%) occurred most frequently amongst the typable strains, whereas 40 (53%) of the 76 strains were nontypable. The results indicate that several serotypes and many nontypable strains were responsible for the sporadic disease occurring during a 10-year period in Australia.

Bedside haemodynamic monitoring: experience in a general hospital

Bedside right heart haemodynamic monitoring was carried out on 55 occasions over 18 months in the cardiac care unit of a district general hospital. The technique was used to assist in the management of 27 patients with acute heart failure by helping to select appropriate treatment. Although the catheters were flow guided, insertion and positioning were facilitated by fluoroscopy. The procedure was safe, with one complication arising; technical difficulties occurred in eight cases. Prediction of cardiac output and left ventricular filling pressure by clinical assessment proved to be accurate in only 55% of cases: in patients with acute heart failure there was a tendency to underestimate the cardiac output (25%) and overestimate the left ventricular filling pressure (37%), whereas in patients with chronic heart failure the filling pressure was more accurately estimated (71%). Haemodynamic measurement was often invaluable in selecting and adjusting treatment, particularly in critically ill patients.

A new serogroup (L) of Neisseria meningitidis

A strain of neisseria meningitidis (LCDC 78189) isolated from the mother of a 3-year-old male with meningococcal meningitis was found to be antigenically distinct from the known serogroups A, B, C, D, H, I, K, X, Y, Z, 29E, and W135; it was designated serogroup L. Anti-78189 serum specifically agglutinated the homologous strain and three other strains which were isolated from the father and two other contacts of the child. Only those strains isolated from the contacts produced immunoprecipitates with the anti-78189 serum by the antiserum-agar method. A structurally unique capsular polysaccharide which was obtained from strain 78189 in a highly purified state was demonstrated to be the antigen responsible for the serological properties of the strain. The polysaccharide formed a precipitin band with the anti-78189 serum but not with the meningococcal grouping sera, and it was also able to absorb both the agglutinating and precipitating activity from the anti-78189 serum.