Water fluoridation, tooth decay in 5 year olds, and social deprivation measured by the Jarman score: analysis of data from British dental surveys

OBJECTIVE

To examine the effect of water fluoridation, both artificial and natural, on dental decay, after socioeconomic deprivation was controlled for.

DESIGN

Ecological study based on results from the NHS dental surveys in 5 year olds in 1991-2 and 1993-4 and Jarman underprivileged area scores from the 1991 census.

SETTING

Electoral wards in three areas: Hartlepool (naturally fluoridated), Newcastle and North Tyneside (fluoridated), and Salford and Trafford (non-fluoridated).

SUBJECTS

5 year old children (n = 10,004).

INTERVENTION

Water fluoridation (artificial and occurring naturally).

MAIN OUTCOME MEASURE

Ward tooth decay score (score on the "decayed, missing, and filled tooth index" for each electoral ward).

RESULTS

Multiple linear regression showed a significant interaction between Jarman score for ward, mean number of teeth affected by decay, and both types of water fluoridation. This confirms that the more deprived an area, the greater benefit derived from fluoridation, whether natural or artificial (R2 = 0.84, P < 0.001). At a Jarman score of zero (national mean score) there was a predicted 44% reduction in decay in fluoridated areas, increasing to a 54% reduction in wards with a Jarman score of 40 (very deprived). The area with natural fluoridation (at a level of 1.2 parts per million-higher than levels in artificially fluoridated areas) had a 66% reduction in decay, with a 74% reduction in wards with a Jarman score of 40.

CONCLUSION

Tooth decay is confirmed as a disease associated with social deprivation, and the more socially deprived areas benefit more from fluoridation. Widespread water fluoridation is urgently needed to reduce the "dental health divide" by improving the dental health of the poorer people in Britain.

Use of reduced sorbent bed and disk membrane solid-phase extraction for the analysis of pharmaceutical compounds in biological fluids, with applications in the 96-well format

Significant improvements in the isolation of pharmaceutical compounds from plasma, serum and urine, have been achieved using ultra low mass sorbent bed and thin disk solid-phase extraction (SPE) material. The use of low sorbent masses or disk SPE material has allowed a significant reduction in solvent usage and extraction times. The reduction in solvent volumes required has allowed elution volumes to be reduced to as low as 30 microl with high and consistent analyte recovery. Several SPE RP-HPLC methods have been developed using these materials, including LC-MS methods. When the chromatographic conditions allow the eluent to be injected directly or injected after dilution with distilled water Empore disks are the extraction media of choice due to the materials low elution volume requirements. When operated in the 96-well microtitre format this micro-extraction provides a very efficient throughput and requires little sample manipulation.

Can a two-state MWC allosteric model explain hemoglobin kinetics?

We have analyzed the nanosecond-millisecond kinetics of ligand binding and conformational changes in hemoglobin. The kinetics were determined from measurements of precise time-resolved optical spectra following nanosecond photodissociation of the heme-carbon monoxide complex. To fit the data, it was necessary to extend the two-state allosteric model of Monod, Wyman, and Changeux (MWC) to include geminate ligand rebinding and nonexponential tertiary relaxation within the R quaternary structure. Considerable simplification of the model is obtained by using a linear free energy relation for the rates of quaternary transitions, and by incorporating concepts from recent studies on the physics of geminate rebinding and conformational changes in myoglobin. The model, described by 85 coupled differential equations, quantitatively explains a demanding set of complex kinetic data. Moreover, with the same set of kinetic parameters it simultaneously fits the equilibrium data on ligand binding and the distribution of ligation states. The present results, together with those from single-crystal oxygen binding studies, indicate that the two-state MWC allosteric model has survived its most critical tests.

Social deprivation and tooth decay in Scottish schoolchildren

OBJECTIVES

To quantify the association between dental decay in Scottish Schoolchildren & social deprivation as measured by the Carstairs Index from the 1991 census.

DESIGN

An ecological study using data from the Scottish Health Boards Dental Epidemiology Programme and The Public Health Common Data set.

SETTING

Scottish Health Boards from 1992-3 to 1994-5.

SUBJECTS

Random samples of 5,920 five-year-olds, 5,344 12-year-olds and 6,007 14-year-olds across the 15 Health Boards in Scotland.

RESULTS

Positive correlations were demonstrated in all age groups; 12-year-olds (r = 0.72) in 1992-3, 5-year-olds (r = 0.8) in 1993-4 and 14-year-olds (r = 0.55) in 1994-5. Dental decay in all age groups was positively and significantly associated with deprivation as measured by the Carstairs index.

CONCLUSION

Tooth decay was confirmed as a disease associated with social deprivation in Scotland. The increasing polarisation of decay to socio-economically deprived groups of the population, suggests a 'whole population' approach such as water fluoridation would prevent tooth decay in these deprived groups most effectively. Nevertheless all evidence-based interventions should be used to try to narrow the "Dental Health Divide' by improving the dental health of deprived individuals.

Index of Orthodontic Treatment Need, its use in a dental epidemiology survey calibration exercise

The Index of Orthodontic Treatment Need (IOTN) was included in a pre-survey calibration exercise of 18 dental epidemiologists. Nine months later 16 of the epidemiologists were re-calibrated in the IOTN. The Index was readily accepted by the experienced dental epidemiological examiners and each examination was estimated to be extended by, on average, less than two minutes. The inter-examiner agreement of the dental health component using the weighted kappa statistic improved from a mean of 0.53 (moderate agreement) for the first calibration to 0.66 (good agreement) at the second calibration. The mean inter-examiner agreement on the aesthetic component using the weighted kappa statistic reduced from 0.52 for the first calibration to 0.49 at the second. Using sensitivity and specificity to measure agreement on the dichotomous decision of those defined as having a definite treatment need, mean sensitivity rose from 0.72 to 0.79 and specificity from 0.90 to 0.97. It is concluded that dental examiners for epidemiological surveys can be trained to use the IOTN by using a pre-calibration exercise and that agreement on the dental health component improves after the index has been used for some months.

Signalling by TGF-beta family members: short-range effects of Xnr-2 and BMP-4 contrast with the long-range effects of activin

BACKGROUND

One way of establishing a morphogen gradient in a developing embryo involves the localized synthesis of an inducing molecule followed by its diffusion into surrounding tissues. The morphogen-like effects of the mesoderm-inducing factor activin provide support for this idea in amphibian development. The questions remain, however, of how activin exerts its long-range effects, and whether long-range signalling is a property of all transforming growth factor beta (TGF-beta) family members.

RESULTS

We compare the signalling ranges of activin and two other TGF-beta family members, Xnr-2 and BMP-4. Unlike activin, Xnr-2 and BMP-4 act over short distances. Furthermore, the effects of constitutively active activin receptors are strictly cell-autonomous. These observations suggest that the long-range effects of activin occur through protein diffusion and that "relay' mechanisms are not initiated by any of these TGF-beta family members. Mechanisms limiting the signalling range of Xnr-2 were addressed by studying Xnr-2 processing and secretion. An activin-Xnr-2 fusion protein signals over many cell diameters, suggesting that regulated processing or secretion is one limiting factor. Disaggregation and reaggregation of Xnr-2-producing tissues also extends the range of Xnr-2, suggesting that components of intact tissue restrict spread of the protein.

CONCLUSIONS

The long-range effects of activin are likely to occur through the diffusion of activin protein. The short-range effects of Xnr-2 and BMP-4 emphasize that long-range diffusion is not a general property of TGF-beta-related molecules. Finally, signalling ranges may be regulated by constraints on processing or secretion and by interactions with extracellular components of embryonic tissues.

A T cell clone with three potential TCR alpha chain rearrangements expresses only one receptor combination at the cell surface

In determining the T cell receptor (TcR) usage of various T cell clones that recognize peptide antigens derived from allergens, a particular clone (AC20) was found, that apparently expressed three different species of mRNA encoding alpha chains. The logical conclusion that the cells were not clonal was refuted by the finding of only a single beta chain rearrangement. One of the alpha chains (V alpha20), was not in frame, but two V alpha8 transcripts of different lengths were both potentially translatable. Sequence analysis suggested that the shorter transcript was generated by a secondary splice event from the longer, through the use of a splice donor sequence encoded by the J alpha38 gene segment. The efficiency of excision of the intervening sequence is such that approximately equal amounts of the long and short transcripts occur in the steady state pool of mRNA. This phenomenon has been reported previously in TcR alpha rearrangements, but it has never been made clear whether these truncated chains can form a functional TcR. Reconstitution of a TcR negative cell line with these transcripts showed that only the full length alpha chain was able to pair efficiently with the beta chain to generate a functional receptor at the cell surface.

ABC of work related disorders. Occupational hearing loss and vibration induced disorders

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Dental electro-anaesthesia in children: a pilot study

Sixty-six children aged 10-17 years, with previous experience of local anaesthesia, had one or more restorations placed while using the Cedeta Mark 2 electronic dental anaesthesia system. A control group of 121 children were treated routinely using injected local anaesthetic. Following all treatment the patients used a 10 cm visual analogue scale to subjectively report the severity of any pain they had experienced. Eighteen (27%) of the study group required injection of local anaesthetic to complete the episode of treatment. The study group had significantly higher pain scores than the control group. It was concluded that further research is warranted to assess the application of this technique to special groups, but that it is not at present a substitute for local anaesthesia by injection in routine paediatric dental practice.

Oligoclonal V gene usage by T lymphocytes in bronchoalveolar lavage fluid from sarcoidosis patients

The T-cell antigen receptor (TCR) repertoire was examined in lymphocytes isolated from the lungs and blood of 12 sarcoidosis patients and nine control patients. This analysis, by polymerase chain reaction (PCR), examined the variable (V)-domain genes of both the alpha and beta chains of the TCR. This is the first study to examine the usage of all known V alpha gene segments in sarcoidosis. A similar degree of diversity was observed in the TCR repertoire in the lungs and blood of the sarcoidosis patients. However, 11 of the 12 sarcoidosis patients showed an increased use of particular TCR V alpha and V beta genes in lung T cells as compared with blood. The pattern of TCR V gene bias in the lung T cells was specific for each patient. The clonality of selected V genes was examined by determining the third complementarity-determining region (CDR3) length polymorphism of particular PCR products. The majority of lung T cells with biased TCR V gene segments were oligoclonal. Altogether, these results suggest oligoclonal expansion of lung T cells in response to a local antigenic stimulus, with additional nonspecific T-cell accumulation. The variability in the V gene segments used by the expanded T-cell subsets in different sarcoidosis patients may reflect different epitopes or antigens being recognized in the lung, as well as variations in major histocompatibility complex (MHC) haplotype between the patients.

Bone morphogenetic protein-4 (BMP-4) acts during gastrula stages to cause ventralization of Xenopus embryos

Injection of RNA encoding BMP-4 into the early Xenopus embryo suppresses formation of dorsal and anterior cell types. To understand this phenomenon, it is necessary to know the stage at which BMP-4 acts. In this paper, we present three lines of evidence showing that BMP-4 misexpression has no effect on the initial steps of mesoderm induction, either dorsal or ventral, but instead causes ventralization during gastrulation. Firstly, activation of organizer-specific genes such as goosecoid, Xnot, pintallavis and noggin occurs normally in embryos injected with BMP-4 RNA, but transcript levels are then rapidly down-regulated as gastrulation proceeds. Similarly, BMP-4 does not affect the initial activation of goosecoid by activin in animal caps, but expression then declines precipitously. Secondly, embryos made ventral by injection with BMP-4 RNA cannot be rescued by grafts of Spemann's organizer at gastrula stages. Such embryos therefore differ from those made ventral by UV-irradiation, where the defect occurs early and rescue can be effected by the organizer. Finally, the dorsalizing effects of the organizer, and of the candidate dorsalizing signal noggin, both of which exert their effects during gastrulation, can be counteracted by BMP-4. Together, these experiments demonstrate that BMP-4 can act during gastrulation both to promote ventral mesoderm differentiation and to attenuate dorsalizing signals derived from the organizer.

Photoaffinity labelling of a receptor structure for macrophage cytotoxicity inducing factor (MCF)

Monocyte cytotoxicity inducing factor (MCF) is a cytokine derived from CD4+ lymphocytes which was isolated using its ability to cause human blood monocytes to become cytotoxic for tumour targets. An N-terminal derived biologically active peptide (GAAVLEDSQ) of the intact molecule was previously used to demonstrate a single class of high affinity binding sites on human blood monocytes and U937 cells. Photoaffinity labelling was carried out to identify the receptor. The N-terminal nonapeptide fragment (P2) could be cross-linked to a single molecular species on the surface of U937 cells when cross-linking was performed on intact cells. Under fully reducing conditions, this molecule had an average molecular weight of 58 kD. In contrast, the apparent molecular weight when determined under nonreducing conditions was 158-163 kD. Octylglucoside solubilized U937 membranes were then applied to a P2 ligand affinity column. The major protein peak when eluted had an apparent molecular weight of 73 kD when determined by a 12% SDS PAGE gel. Photoaffinity labelling of the ligand affinity product was carried out in solution. Gel electrophoresis under nonreducing conditions demonstrated cross-linking to a 163 kD and a 29 kD protein, while under reducing and denaturing conditions additional species were seen at 97 kD, 67 kD and 50 kD. Photoaffinity cross-linking performed both on whole cells and partially purified receptor in solution, and could be specifically abolished by the addition of unlabelled peptide. These data present evidence that the single high affinity binding site corresponds to a U937 membrane protein having an average molecular weight of 58 kD which exists as an apparent homodimer under native conditions, but may have additional low molecular weight components which were not available for binding and derivatization using intact cells.

Nodal-related signals induce axial mesoderm and dorsalize mesoderm during gastrulation

Mouse embryos homozygous for a null mutation in nodal arrest development at early gastrulation and contain little or no embryonic mesoderm. Here, two Xenopus nodal-related genes (Xnr-1 and Xnr-2) are identified and shown to be expressed transiently during embryogenesis, first within the vegetal region of late blastulae and later in the marginal zone during gastrulation, with enrichment in the dorsal lip. Xnrs and mouse nodal function as dose-dependent dorsoanterior and ventral mesoderm inducers in whole embryos and explanted animal caps. Using a plasmid vector to produce Xnr proteins during gastrulation, we show that, in contrast to activin and other TGF beta-like molecules, Xnr-1 and Xnr-2 can dorsalize ventral marginal zone explants and induce muscle differentiation. Xnr signalling also rescues a complete embryonic axis in UV-ventralized embryos. The patterns of Xnr expression, the activities of the proteins and the phenotype of mouse nodal mutants, all argue strongly that a signaling pathway involving nodal, or nodal-related peptides, is an essential conserved element in mesoderm differentiation associated with vertebrate gastrulation and axial patterning.

Children's ratings of dental injection and treatment pain, and the influence of the time taken to administer the injection

Three hundred and eight children aged 3-16 years (mean age 10.2), who were undergoing routine dental treatment, recorded on visual analogue scales their ratings of pain associated with injection and treatment. The injection pain scores were examined for their relationship to age, gender, time taken to administer the injection and injection type. The treatment pain scores were compared between groups who had teeth either extracted or restored, and between groups assessed by the operator as having total or partial anaesthesia. A significant inverse correlation was found between subjective injection pain and injection duration. The difference in treatment pain scores was significant between groups assessed by the operator as having total or partial anaesthesia. Inferior dental nerve blocks were rated significantly more painful than buccal infiltrations. Age, gender, and the operative procedure performed had no statistically significant relationship to the injection pain scores or treatment pain scores. The visual analogue pain scale was found to be unsuitable for use by children under 7 years of age.

Inductive signals. Revolving vertebrates

An old idea about the relationship between arthropod and vertebrate body plans has been given new life by studies of the signalling genes controlling dorsal and ventral development in Drosophila and Xenopus.

Reasoning about curvilinear motion: using principles or analogy

People possess implicit theories about the motion of objects, theories that are often incorrect. When asked to predict the path of an object emerging from a curved tube, for example, people often say that the object will continue to follow a curved path. However, when solving a problem that reminds them of a familiar previous instance, people often reason by analogy to the instance. In this study, we show that a previous instance must be very superficially similar to a problem in order to be used as an analogy; otherwise, people will use their implicit theories as the basis of their reasoning.

Acute encephalopathy and status epilepticus associated with human herpes virus 6 infection

A previously healthy 22-month-old boy presented in status epilepticus with high fever. He was comatose, with upper respiratory-tract infection. The seizures responded to anticonvulsant therapy. The boy's temperature returned to normal within 24 hours and he recovered slowly from his encephalopathy. On the third hospital day, he exhibited the characteristic rash of reseola infantum. Acute infection with human herpes virus 6 (HHV-6) was established serologically by enzyme immunoassay. HHV-6 DNA was not detected by polymerase chain reaction in CSF or serum at the onset of illness, but was found three months later in the child's saliva. The pathogenesis of the patient's encephalopathy is discussed. It is concluded that HHV-6 infection should be considered in infants and young children with febrile status epilepticus.

Human MCF activates monocytes to produce IL-1 but not TNF or CSF-1

Monocyte cytotoxicity inducing factor (MCF) is a novel cytokine which was originally characterized by its ability to induce monocyte cytotoxicity against tumor targets. The present studies were undertaken to define the mechanisms of cytotoxicity. Since the cytotoxic state may be mediated, in part, by the secretion of monokines, MCF's effect on IL-1, TNF and CSF-1 were measured. MCF caused human peripheral blood monocytes to secrete large amounts of IL-1 but not TNF. In contrast monocytes produce CSF-1 in culture and this production was not enhanced by MCF. IL-1 neither appeared to directly lyse the target K562 nor was able to activate macrophages for cytotoxicity. However, IL-1 may be necessary for lysis of K562 by activated macrophages through its cytostatic effect on K562. MCF increased monocyte surface expression of DR-beta (when studied by fluorescent microfluorometry) and messenger RNA for DR-beta after 24 h in culture. These functional studies indicate that MCF is a cytokine with a distinct spectrum of biologic activities whose functions may be mediated by synthesis and secretion of IL-1.

Acute aortic occlusion. A 40-year experience

OBJECTIVE

To review a large experience with acute aortic occlusion (AAO) to better define the cause, clinical presentation, treatment, prognostic variables, and outcome.

DESIGN

Retrospective review of 46 consecutive patients with AAO during a 40-year period.

SETTING

A large urban tertiary care referral center in Detroit, Mich.

PATIENTS

Adult patients with arteriographic and/or operative confirmation of acute occlusion of the abdominal aorta plus signs and symptoms of acute ischemia.

INTERVENTION

Operative and nonoperative treatment of AAO.

MAIN OUTCOME MEASURES

Mortality, morbidity, and long-term survival. Other variables measured included cause, risk factors, and effects of duration and severity of ischemia and treatment methods on outcome.

RESULTS

Two primary causes were identified--embolism (65%) and thrombosis (35%). Heart disease and female gender were risk factors for embolism, while smoking and diabetes were risk factors for thrombosis. Severity of ischemia on presentation correlated better with outcome than duration of ischemia. The hospital mortality rate was 35% and morbidity, 74%, with no difference between the two groups. Recurrent arterial embolism occurred in 43% of patients with embolic AAO. Seventy-two percent of AAO survivors were alive 5 years after therapy.

CONCLUSIONS

Acute aortic occlusion remains a serious vascular surgical emergency with significant morbidity and mortality, even when recognized promptly and treated appropriately. Nevertheless, survivors have a reasonable long-term outcome. Permanent anticoagulation is suggested in patients with embolic AAO to minimize a high incidence of recurrent arterial embolism.

Conformational relaxation and ligand binding in myoglobin

Absorption spectroscopy with nanosecond time resolution shows that myoglobin undergoes conformational relaxation on the same time scale as geminate rebinding of carbon monoxide. Ligand rebinding following photodissociation of the heme-CO complex was measured from the amplitude of the average difference spectrum, while conformational changes were measured from changes in the detailed shape of the Soret spectra of the deoxyhemes. Experiments in which the solvent viscosity was varied between 1 and 300 cP and the temperature between 268 and 308 K were analyzed by fitting the multiwavelength kinetic data with both empirical and molecular models. Novel numerical techniques were employed in fitting the data, including the use of singular value decomposition to remove the effects of temperature and solvent on the spectra and of a Monte Carlo method to overcome the multiple minimum problem in searching parameter space. The molecular model is the minimal model that incorporates all of the major features of myoglobin kinetics at ambient temperatures, including a fast and slow rebinding conformation and two geminate states for each conformation. The results of fitting the kinetic data with this model indicate that the geminate-rebinding rates for the two conformations differ by at least a factor of 100. The differences between the spectra of the two conformations generated from the fits are similar to the differences between those of the R and T conformations of hemoglobin. In modeling the data, the dependence of the rates on temperature and viscosity was parametrized using a modification of Kramers theory which includes the contributions of both protein and solvent to the friction. The rate of the transition from the fast to the slow rebinding conformation is found to be inversely proportional to the viscosity when the viscosity exceeds about 30 cP and nearly viscosity independent at low viscosity. The viscosity dependence at high viscosities suggests that the two conformations differ by the global displacement of protein atoms on the proximal side of the heme observed by X-ray crystallography. We suggest that the conformational change observed in our experiments corresponds to the final portion of the nonexponential conformational relaxation recently observed by Anfinrud and co-workers, which begins on a picosecond time scale. Furthermore, extrapolation of our data to temperatures near that of the solvent glass transition suggests that this conformational relaxation may very well be the one postulated by Frauenfelder and co-workers to explain the decrease in the rate of geminate rebinding with increasing temperature above 180 K.

Degeneracy of T cell receptor recognition of an influenza virus hemagglutinin epitope restricted by HLA-DQ and -DR class II molecules

DT9301-0229737 the TcR are believed to provide the peptide fragments bound to major histocompatibility (MHC) molecules. TcR have an immunoglobulin (Ig)-like structure and, in an analogous manner to antigen recognition by Ig, the third complementarity determining regions (CDR3) of the TcR are believed to provide the primary contact with the peptide lying in the MHC groove. CDR1 and CDR2 are thought to contact the presenting MHC molecule. We have analyzed seven human CD4+ T cell clones that recognize a conserved peptide epitope (residues 255-270) within the influenza virus hemagglutinin (H3) HA1 subunit. Two T cell clones recognized the peptide in the context of HLA-DRB1*1001 and HLA-DQB1*0602/DQA1*0102, respectively, and shared V alpha, V beta and J beta gene segments. Only the junctional regions encoding the CDR3 regions of the two TcR chains were different. This suggests that the CDR3 regions of these TcR interact with the MHC class II molecule. Six of the T cell clones were restricted by the HLA-DRB1*1001. Two of these T cell clones expressed V beta 9.1 and three expressed V beta 13 gene segments; the remaining clone expressed V beta 7.2, a close homologue of V beta 9.1. A diverse selection of V alpha and J gene segments contributed to the junctional heterogeneity of the TcR, indicating a diversity of sequence combinations recognizing the epitope. Nevertheless, five out of six T cell clones bore a motif in the V alpha CDR3 loop consisting of adjacent acidic and polar amino acid residues, eight residues from the carboxyl end of each CDR3.

Embryonic expression of mouse bone morphogenetic protein-1 (BMP-1), which is related to the Drosophila dorsoventral gene tolloid and encodes a putative astacin metalloendopeptidase

cDNAs encoding a mouse gene closely related to human bone morphogenetic protein-1 (BMP-1) have been isolated from an 8.5-day p.c. embryo cDNA library. Analysis of the predicted amino acid sequence shows that the protein contains a putative zinc-binding astacin metalloendopeptidase domain, five Clr/s domains, and two potential Ca(2+)-binding EGF-like repeats. In overall domain organization it more closely resembles the Drosophila tolloid gene product than human BMP-1. By RNase protection, transcripts can be detected in the embryo at 6.5 days p.c. and persist at least until 16.5 days p.c. By in situ hybridization, transcripts are seen at high levels in the maternal deciduum and in the late-gastrulation stage embryo at low levels throughout the mesoderm. This low level of mesodermal expression continues through development but somewhat higher levels are seen in developing membranous and endochondral bone, in the submucosa of the intestine, the dermis of the skin, and the mesenchyme of the spleen and lung. High levels of BMP-1 transcripts are also seen from 9.5 days p.c. in the floorplate region of the developing neural tube. Potential therefore exists for the interaction of BMP-1 protein with products of TGF-beta-related genes expressed during embryogenesis.

Synthetic macrophage activating peptides derived from the N-terminus of human MCF

Recently, we described the purification and N-terminal sequencing of a novel cytokine termed MCF (Monocyte Cytotoxicity Inducing Factor) (1,2). In order to study the interaction of this cytokine with monocytes, we synthesized a nona-peptide GAAVLEDSQ corresponding to the N-terminus of MCF: two truncated peptides, GAAVL and LEDSQ; and the substituted peptide, GAAVLENSQ. The authentic N-terminal peptide is biologically active in the nanomolar range, while substitution of asparagine for aspartic acid at position 7 diminishes biological activity. Biological activity was observed from the C-terminal fragment LEDSQ, but the N-terminal pentapeptide (GAAVL) was devoid of biological activity. Scatchard analysis revealed a single class of saturable high affinity sites. These studies indicate that the N-terminus of MCF is important in interacting with the binding site on monocytes and it may be possible to design synthetic activators and inhibitors of monocyte/macrophage cytotoxicity.

Embryonic expression of Lim-1, the mouse homolog of Xenopus Xlim-1, suggests a role in lateral mesoderm differentiation and neurogenesis

cDNAs encoded by the mouse homolog (Lim-1) of the Xenopus LIM-class homeobox gene Xlim-1 have been isolated from an 8.5-day mouse embryo cDNA library. Nucleotide and deduced amino acid sequences show a high degree of identity with Xlim-1 in the LIM and homeodomains, and 85% identity over the whole protein. An interspecific back-cross has been used to show close linkage of Lim-1 to the endogenous proviral marker Mpmv-4 on mouse chromosome 11. Whole mount in situ hybridization studies have been carried out on mouse embryos between 6.5 and 10.5 days. In mid- to late-streak stage embryos, Lim-1 is expressed in a restricted region of mesoderm in the primitive streak, with the highest level of signal at the anterior. At 7.5 days, transcripts can be seen in a horseshoe-shaped pattern in the periphery of the node, as well as along both sides of the immediately adjacent notochord. In addition, transcripts are present in presumptive lateral and intermediate mesoderm. Later, expression becomes progressively restricted to intermediate mesoderm, the nephrogenic cords, and eventually mesonephric ducts and tubules. By 10.5 days Lim-1 transcripts also appear in restricted regions of the central nervous system (CNS) that are associated with sensory function. The lateral diencephalon, hindbrain, and presumed commissural neurons in the dorsal spinal cord all show Lim-1 expression. In the adult, Lim-1 is expressed in the cerebellum/medulla and kidney, and at very low levels in the cerebrum. These data suggest that in the mouse embryo Lim-1 plays a role in early mesoderm formation and later specification of a differentiated phenotype in subsets of cells of the mesonephros and sensory neurons of the CNS.

Fast events in protein folding initiated by nanosecond laser photolysis

Initiation of protein folding by light can dramatically improve the time resolution of kinetic studies. Here we present an example of an optically triggered folding reaction by using nanosecond photodissociation of the heme-carbon monoxide complex of reduced cytochrome c. The optical trigger is based on the observation that under destabilizing conditions cytochrome c can be unfolded by preferential binding of carbon monoxide to the covalently attached heme group in the unfolded state. Photodissociation of the carbon monoxide thus triggers the folding reaction. We used time-resolved absorption spectroscopy to monitor binding at the heme. Before folding begins we observe transient binding of both nonnative and native ligands from the unfolded polypeptide on a microsecond time scale. Kinetic modeling suggests that the intramolecular binding of methionine-65 and -80 is faster than that of histidine-26 and -33, even though the histidines are closer to the heme. This optical trigger should provide a powerful method for studying chain collapse and secondary structure formation in cytochrome c without any limitations in time resolution.

An evaluation of the total similarity principle: effects of similarity on frequency judgments

Memory models that embody the total similarity principle (e.g., Gillund & Shiffrin, 1984; Hintzman, 1988; Murdock, 1982; Ratcliff, 1990) assume that frequency judgments reflect the total similarity of a test item to stimuli that have been studied. In 4 experiments, subjects estimated the frequencies of target words that had been presented in the context of varying numbers of semantically similar words. In a fifth experiment, subjects made forced-choice relative frequency judgments. The results of these experiments supported 1 prediction of total similarity models: Presenting similar words will increase rather than decrease frequency judgments of target words. However, a second prediction of these models was not supported. In particular, similar-word presentations had no effect on the judged frequencies of target words that had not been shown.

Transforming growth factor beta gene expression is transiently enhanced at a critical stage during liver regeneration after CCl4 treatment

BACKGROUND

Transforming growth factor beta 1 (TGF beta 1) gene expression is increased in CCl4-injured rat livers. The biologic link of this increase and liver regeneration has not been established.

EXPERIMENTAL DESIGN

To explore the identity of the TGF beta 1-producing cells in the CCl4 regenerating liver, we hybridized untreated and CCl4-treated liver sections of TGF beta 1-specific riboprobes and immunolocalized TGF beta 1 protein, simultaneously. To assess the dynamics of cellular proliferation during hepatic regeneration, chronologic changes in the cellular DNA synthesis were also monitored by [3H]thymidine incorporation and autoradiography. In situ hybridization analyses were further extended by subfractionation of nonparenchymal cells into Kupffer cells/macrophages, endothelial and Ito cells, and determining TGF beta 1 mRNA levels in different cell types. Finally, we experimentally tested if the temporal relationship between the transient elevation of expression of TGF beta 1 and hepatic cell proliferation were casually related.

RESULTS

We observed that the rate of DNA synthesis was the highest around 36 hours post-treatment and preceded the time of enhanced accumulation of TGF beta 1 transcripts and protein, both of which peaked at approximately 48 hours and declined thereafter. Transient upregulation of TGF beta 1 gene expression was seen in the inflammatory cell infiltrates around the central vein and at less extent, in portal tracts, and in perisinusoidal cells near the zone of necrosis. Like TGF beta 1 transcripts, TGF beta 1 protein was also predominantly co-localized in and around the pericentral and periportal cells. Kupffer cells, that accumulate abundantly in the liver 48 hours after CCl4 administration, were the primary producers of TGF beta 1. The injection of neutralizing anti-TGF beta 1 antibodies into animals prevented both the decline in [3H]thymidine incorporation and cell division in the waning phases of hepatic regeneration at 72 hours.

CONCLUSIONS

Based on our observations that (i) TGF beta 1 gene expression is triggered transiently during a crucial phase of liver regeneration, (ii) the exogenously added TGF beta 1 inhibits hepatic DNA synthesis and that (iii) the administration of TGF beta 1 antibodies extends the proliferative response of the regenerating liver, we conclude that TGF beta 1 plays a pivotal role in down regulating liver regeneration.

An evaluation of the total similarity principle: effects of similarity on frequency judgments

Memory models that embody the total similarity principle (e.g., Gillund & Shiffrin, 1984; Hintzman, 1988; Murdock, 1982; Ratcliff, 1990) assume that frequency judgments reflect the total similarity of a test item to stimuli that have been studied. In 4 experiments, subjects estimated the frequencies of target words that had been presented in the context of varying numbers of semantically similar words. In a fifth experiment, subjects made forced-choice relative frequency judgments. The results of these experiments supported 1 prediction of total similarity models: Presenting similar words will increase rather than decrease frequency judgments of target words. However, a second prediction of these models was not supported. In particular, similar-word presentations had no effect on the judged frequencies of target words that had not been shown.

Dissociation kinetics of actinomycin D from oligonucleotides with hairpin motifs

The dissociation of 7-aminoactinomycin D (7-AM-ACTD) from d(ATGCATATGCAT), d(ATGCAT-T-ATGCAT), or d(ATGCAT-A-ATGCAT) at 20 degrees C cannot be adequately described by a single-exponential decay and requires a fit with two rate constants. The relative contributions of these two rate processes and their temperature dependence can be attributed to the coexistence of two conformational species in solutions. The slow dissociation rate corresponds to oligonucleotides in the dimeric duplex form, whereas the fast rate occurs with those in the hairpin conformation. The increased relative contribution of the faster component at higher temperatures is consistent with the more favorable thermal stability of the hairpin form. Studies with d(ATGCAT-TTT-ATGCAT) and d(ATGCAT-AAA-ATGCAT), which exist predominantly in the hairpin conformation, indicate that 7-AM-ACTD dissociates from these oligomers single-exponentially with rate constants comparable to or less than those obtained for the dimeric duplex of d(ATGCATATGCAT). Equilibrium binding titrations suggest that ACTD binds to hairpins as strongly as to the related dimeric duplexes, suggesting that the stacking geometry of the G.C base pairs at the dG-dC intercalating site of the hairpin stem is not greatly different from that of the dimeric duplex. The considerable variation in the dissociation rates of 7-AM-ACTD from hairpins, however, reflects the varying degrees of DNA minor-groove distortion of the stem duplex resulting from the hairpin loop formation and consequent interactions with the pentapeptide rings of ACTD. The plausibility of our interpretation is further supported by results from electrophoretic measurements, thermal melting profiles, and additional studies with hairpins containing a CGCG or GCGC stem.

Chronic headache and nocturnal bruxism in a 5-year-old child treated with an occlusal splint

A report is presented of a 5-year-old girl who had an 11-month history of chronic headache and nocturnal bruxism. Treatment using a removable appliance that provided maximum support in centric relation was successful in relieving the headache during a follow-up period of 22 months.

Photoselection in polarized photolysis experiments on heme proteins

Polarized photolysis experiments have been performed on the carbon monoxide complex of myoglobin to assess the effects of photoselection on the kinetics of ligand rebinding and to investigate the reorientational dynamics of the heme plane. The results are analyzed in terms of the optical theory developed in the preceding paper by Ansari and Szabo. Changes in optical density arising from rotational diffusion of the photoselected population produce large deviations from the true geminate ligand rebinding curves if measurements are made with only a single polarization. The apparent ligand rebinding curves are significantly distorted even at photolysis levels greater than 90%. These deviations are eliminated by obtaining isotropically-averaged optical densities from measurements using both parallel and perpendicular polarizations of the probe pulse. These experiments also yield the optical anisotropy, which gives a novel method for accurately determining the degree of photolysis, as well as important information on the reorientational dynamics of the heme plane. The correlation time for the overall rotational diffusion of the molecule is obtained from the decay of the anisotropy. The anisotropy prior to rotational diffusion is lower than that predicted for a rigidly attached, perfectly circular absorber, corresponding to an apparent order parameter of S = 0.95 +/- 0.02. Polarized absorption data on single crystals suggest that the decreased anisotropy results more from internal motions of the heme plane which take place on time scales shorter than the duration of the laser pulse (10 ns) than from out-of-plane polarized transitions.

Transgenic mice as a model to study the role of TGF-beta-related molecules in hair follicles

There is increasing evidence that members of the TGF-beta superfamily are important regulators of epithelial growth and differentiation in vivo. Here, transgenic mice have been used to study the role of the TGF-beta-related growth factors BMP-2 and BMP-4 in hair and whisker development. In the mature hair follicle, BMP-2 transcripts are normally seen only in precortex cells at the base of the hair shaft. In the transgenic mice reported here, BMP-4, a closely related molecule, has been ectopically expressed in the outer root sheath of hair and whisker follicles using an expression vector based on the bovine cytokeratin IV* promoter. In response to transgene expression, both outer root sheath cells below the stem cell compartment and hair matrix cells around the dermal papilla cease proliferation. In addition, the expression pattern of cytokeratin markers is disturbed in some transgenic hair follicles. These results support a model in which members of the TGF-beta superfamily play an active role in the inhibiton of cell proliferation and the onset of expression of trichocyte-specific genes that take place when cells leave the matrix of the follicle and differentiate into shaft cells.

Photodynamic therapy in the treatment of Bowen's disease

BACKGROUND

The treatment of Bowen's disease in anatomically difficult areas or especially large lesions can challenge accepted modalities of treatment.

OBJECTIVE

The purpose of this study was to illustrate the effectiveness of photodynamic therapy in the treatment of Bowen's disease. In addition, photodynamic therapy may be used as adjuvant therapy for difficult lesions.

METHODS

Six patients with Bowen's disease in various anatomic sites were treated with photodynamic therapy. Four were in a difficult anatomic site, or were especially large, or both. Photofrin, 1.0 mg/kg, was administered intravenously and laser treatment was given approximately 48 hours later with the argon dye laser. Light was administered at a wavelength of 630 nm and the light dose ranged from 185 to 250 joules/cm2. Treatment was given by surface radiation only.

RESULTS

Eight lesions were treated. All showed a complete response at 3 months (100%) and continue to show a complete response at 6 and 12 months. Morbidity was low; the most significant side effects were moderate pain and edema. Healing time varied depending on the size of the lesion.

CONCLUSION

Photodynamic therapy is an effective and useful alternative for Bowen's disease, especially those lesions in anatomically difficult areas or those that are especially large.

Isolation of Vgr-2, a novel member of the transforming growth factor-beta-related gene family

A cDNA clone, Vgr-2, with homology to certain members of the transforming growth factor-beta superfamily has been isolated from a mouse embryo cDNA library. The encoded protein shows significant similarity to members of the Vg-1/decapentaplegic/bone morphogenetic protein subgroup of the transforming growth factor-beta family. Within this group, Vgr-2 is more similar to Xenopus Vg-1 than to any other member so far isolated. The gene is expressed at highest levels during midgestation mouse development, and transcripts are localized by in situ hybridization to the osteogenic zone of developing bone. Vgr-2 is expressed in F9 teratocarcinoma cells, and its RNA levels are down-regulated within 24 h after differentiation with retinoic acid. The genomic organization of Vgr-2 and its location on mouse chromosome 6 are reported.

Histoplasmosis in hairy cell leukemia: case report and review of the literature

Progressive disseminated histoplasmosis (PDH) has been described in only six patients with hairy cell leukemia (HCL). Herein we describe an additional patient with HCL and disseminated histoplasmosis. Additionally, we note that three of seven cases of disseminated histoplasmosis and HCL have occurred in East Texas. PDH is to be suspected in febrile HCL patients in an endemic area who fail to respond to antibacterial therapy. We emphasize that serologic studies are useful in the diagnosis of PDH in HCL patients, and these patients respond well to therapy.

Speed of intersubunit communication in proteins

To determine the speed of communication between protein subunits, time-resolved absorption spectra were measured following partial photodissociation of the carbon monoxide complex of hemoglobin. The experiments were carried out using linearly polarized, 10-ns laser pulses, with the polarization of the excitation pulse both parallel and perpendicular to the polarization of the probe pulse. The substantial contribution to the observed spectra from photoselection effects was eliminated by isotropically averaging the polarized spectra, allowing a detailed comparison of the kinetics as a function of the degree of photolysis. These results show that prior to 1 microsecond both geminate ligand rebinding and conformational relaxation are independent of the number of ligands dissociated from the hemoglobin tetramer, as expected for a two-state allosteric model. After this time the kinetics depend on the ligation state of the tetramer. The conformational relaxation at 10 microseconds can be interpreted in terms of the two-state allosteric model as arising from the R to T quaternary conformational change of both unliganded and singly liganded molecules. These results suggest that communication between subunits requires about 1 microsecond and that the mechanism of the communication which occurs after this time is via the R to T conformational change. The optical anisotropy provides a novel means of accurately determining the extinction coefficients of the transient photoproduct. The decay in the optical anisotropy, moreover, provides an accurate determination of the rotational correlation time of 36 +/- 3 ns.

The role of solvent viscosity in the dynamics of protein conformational changes

Nanosecond lasers were used to measure the rate of conformational changes in myoglobin after ligand dissociation at ambient temperatures. At low solvent viscosities the rate is independent of viscosity, but at high viscosities it depends on approximately the inverse first power of the viscosity. Kramers theory for unimolecular rate processes can be used to explain this result if the friction term is modified to include protein as well as solvent friction. The theory and experiment suggest that the dominant factor in markedly reducing the rate of conformational changes in myoglobin at low temperatures (less than 200 K) is the very high viscosity (greater than 10(7) centipoise) of the glycerol-water solvent. That is, at low temperatures conformational substates may not be "frozen" so much as "stuck."

DVR-4 (bone morphogenetic protein-4) as a posterior-ventralizing factor in Xenopus mesoderm induction

Establishment of mesodermal tissues in the amphibian body involves a series of inductive interactions probably elicited by a variety of peptide growth factors. Results reported here suggest that mesodermal patterning involves an array of signalling molecules including DVR-4, a TGF-beta-like molecule. We show that ectopic expression of DVR-4 causes embryos to develop with an overall posterior and/or ventral character, and that DVR-4 induces ventral types of mesoderm in animal cap explants. Moreover, DVR-4 overrides the dorsalizing effects of activin. DVR-4 is therefore the first molecule reported both to induce posteroventral mesoderm and to counteract dorsalizing signals such as activin. Possible interactions between these molecules resulting in establishment of the embryonic body plan are discussed.

Expression and modification of Hox 2.1 protein in mouse embryos

A polyclonal antibody, alpha Hox 2.1a, has been generated and used to immunolocalize Hox 2.1 protein in mouse embryos. Protein is present in nuclei of all tissues previously shown to express Hox 2.1 RNA. In addition, protein is seen in somites and proximal regions of the limb buds, tissues in which Hox 2.1 RNA expression was not clearly detected previously by in situ hybridization. At the 7 somite stage, protein is detectable in the neural tube up to the level of somite 1, but later retracts to a more posterior position. Immunoblot, in vitro translation, and immunoprecipitation experiments were carried out to characterize the Hox 2.1 protein. The results show that the Hox 2.1 gene produces at least two related phosphorylated proteins present in different proportions in different tissues.

Alzheimer disease paired helical filament core structures contain glycolipid

The core structures of sodium dodecyl sulfate extracted, pronase digested paired helical filaments of Alzheimer disease were solubilized by heating in dimethyl sulfoxide. Electron microscopy revealed that after heating in dimethyl sulfoxide, intact paired helical filaments were no longer present in the dimethyl sulfoxide soluble fractions or in the insoluble lipofuscin-containing fractions. Enzyme-linked immunosorbent assays of the various fractions with the monospecific antibody A128 to paired helical filaments demonstrated 96% of the immunoreactivity to be in the dimethyl sulfoxide soluble fraction, and only 4% in the dimethyl sulfoxide insoluble fractions. Lyophilization of the dimethyl sulfoxide soluble supernatant and resuspension in water failed to reassociate the paired helical filaments, but did result in an insoluble precipitate. Analysis of the dimethyl sulfoxide solubilized paired helical filament fraction by nuclear magnetic resonance revealed it to be composed of glycolipid in a form that was distinct from similar fractions isolated from normal aged control brains. The aggregation of an altered glycolipid to form paired helical filaments in Alzheimer disease could explain their insolubility.

The DVR gene family in embryonic development

The DVR gene family consists of at least 15 members, including decapentaplegic from Drosophila, Xenopus Vg1 and the mammalian bone morphogenetic protein genes, encoding secreted proteins closely related to transforming growth factor beta Genetic and biochemical evidence supports the idea that DVR proteins form part of a cascade of extracellular signalling molecules mediating inductive tissue interactions during development.

The parietal cell autoantigens recognized in neonatal thymectomy-induced murine gastritis are the alpha and beta subunits of the gastric proton pump [corrected]

Murine autoimmune gastritis, induced by neonatal thymectomy, bears a striking similarity in pathology to the human autoimmune disease, pernicious anemia. Autoantibodies to parietal cells are found in both murine and human diseases. Monoclonal immunoglobulin G autoantibodies, obtained from neonatally thymectomized mice, have previously been shown to recognize two groups of gastric parietal cell antigens. In the present study, it is shown that two of these monoclonal autoantibodies, designated 1H9 and 2B6, are directed against the alpha subunit and beta subunit, respectively, of the gastric hydrogen-potassium-stimulated adenosine triphosphatase (H+,K(+)-ATPase; proton pump). Monoclonal antibody 1H9 showed reactivity by immunoblotting with a 95-kilodalton component of dog gastric tubulovesicular membranes and with a fusion protein containing the hydrophilic domain of the alpha subunit of the H+,K(+)-ATPase. Monoclonal antibody 2B6 reacted by immunoblotting with the 60-90-kilodalton glycoprotein (beta subunit) of the tomato lectin-purified dog H+,K(+)-ATPase and with the 60-90-kilodalton autoantigen purified with human parietal cell autoantibodies. Monoclonal antibody 2B6 also reacted with the deglycosylated 35-kilodalton core protein of the tomato lectin-purified 60-90-kilodalton beta subunit and of the purified 60-90-kilodalton autoantigen. Parietal cell autoantibody-positive sera from 20 mice with experimentally induced gastritis showed reactivity predominantly with the alpha and/or beta subunit of the gastric H+,K(+)-ATPase. Therefore, it is concluded that the major molecules targeted by parietal cell autoantibodies from mice with neonatal thymectomy-induced murine autoimmune gastritis and from humans with pernicious anemia are identical.

Purification and amino acid analysis of a human macrophage cytotoxicity-inducing factor (MCF)

Recently we have described a CD4+ human T-cell hybridoma Ft.F3 (ATCC HB 9713). This hybridoma produces two proteins having molecular weights of 29 kd (P29) and 14.7 kd (P14.7) that function as activators of human monocyte tumor cytotoxicity and interleukin 1 (IL-1) synthesis (macrophage cytotoxicity-inducing factors, MCFs). Both MCF species were purified to apparent homogeneity, as assessed by two-dimensional (2D) gel electrophoresis, by a combination of dye ligand, ion exchange, and hydrophobic interaction chromatography, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Exhaustive treatment of P29 by endoglycosidase F, performic acid, and 40x molar excess 2-mercaptoethanol failed to generate P14.7 from P29. Antisera raised to P29 recognized only P29 in immunoblots of 2D gels of crude hybridoma supernatant. Amino acid composition analyses of both species are similar but not identical. These MCFs appear to be distinct but possibly related proteins important in the inflammatory response, whereas N-terminal analysis of P29 reveals it to be a previously undescribed cytokine.

Dynamics of the quaternary conformational change in trout hemoglobin

The kinetics of conformational changes in trout hemoglobin I have been characterized over the temperature range 2-65 degrees C from time-resolved absorption spectra measured following photodissociation of the carbon monoxide complex. Changes in the spectra of the deoxyheme photoproduct were used to monitor changes in the protein conformation. Although the deoxyheme spectral changes are only about 8% of the total spectral change due to ligand rebinding, a combination of high-precision measurements and singular value decomposition of the data permits a detailed analysis of both their amplitudes and relaxation rates. Systematic variation of the degree of photolysis was used to alter the distribution of liganded tetramers, permitting the assignment of the spectral relaxation at 20 microseconds to the R----T quaternary conformational change of the zero-liganded and singly liganded molecules and spectral relaxations at about 50 ns and 2 microseconds to tertiary conformational changes within the R structure. Analysis of the effect of photoselection by the linearly polarized excitation pulse indicates that a major contribution to the apparent geminate rebinding in the 50-ns relaxation arises from rotational diffusion of molecules containing unphotolyzed heme-CO complexes. The activation enthalpy and activation entropy for the R0----T0 transition are +7.4 kcal/mol and -12 cal mol-1 K-1. Using the equilibrium data, delta H = +29.4 kcal/mol and delta S = +84.4 cal mol-1 K-1 [Barisas, B. G., & Gill, S. J. (1979) Biophys. Chem. 9, 235-244], the activation parameters for the T0----R0 transition are calculated to be delta H = +37 kcal/mol and delta S = +73 cal mol-1 K-1. The similarity of the equilibrium and activation parameters for the T0----R0 transition indicates that the transition state is much more R-like than T-like. This result suggests that in the path from T0 to R0 the subunits have already almost completely rearranged into the R configuration when the transition state is reached, while in the path from R0 to T0 the subunits remain in a configuration close to R in the transition state. The finding of an R-like transition state explains why the binding of ligands causes much smaller changes in the R----T rates than in the T----R rates.

Monoclonal antibodies specific for the core protein of the beta-subunit of the gastric proton pump (H+/K+ ATPase). An autoantigen targetted in pernicious anaemia

The gastric H+/K(+)-transporting adenosine triphosphatase (H+/K+ ATPase) (proton pump) consists of a catalytic alpha-subunit and a recently proposed 60-90-kDa glycoprotein beta-subunit. Using dog gastric membranes as the antigen, we have produced two murine monoclonal antibodies, 4F11 (IgG1) and 3A6 (IgA), which are specific for the 60-90-kDa glycoprotein. The monoclonal antibodies (1) specifically stained the cytoplasm of unfixed and formalin-fixed dog gastric parietal cells; (2) specifically reacted by ELISA with gastric tubulovesicular membranes; (3) recognised epitopes located on the luminal face of parietal cell tubulovesicular membranes, the site of the proton pump, by immunogold electron microscopy; (4) immunoblotted a 60-90-kDa molecule from tubulovesicular membranes and a 35-kDa component from peptide N-glycosidase-F-treated membrane extracts; (5) immunoblotted the 60-90-kDa parietal cell autoantigen associated with autoimmune gastritis and pernicious anemia, purified by chromatography on parietal cell autoantibody- or tomato-lectin-Sepharose 4B affinity columns, and the 35-kDa protein core of this autoantigen; this autoantigen has amino acid sequence similarity to the beta-subunit of the related Na+/K(+)-transporting adenosine triphosphatase (Na+/K+ ATPase) [Toh et al. (1990) Proc. Natl Acad. Sci. 87, 6418-6422]; (6) co-precipitated a molecule of 95 kDa with the 60-90-kDa molecule from 125I-labelled detergent extracts of dog tubulovesicular membranes; and (7) co-purified the catalytic alpha-subunit of the H+/K+ ATPase with the 60-90-kDa molecule by immunoaffinity chromatography of tubulovesicular membrane extracts on a monoclonal antibody 3A6-Sepharose 4B column, indicating a physical association between the two molecules. These results provide further evidence that the 60-90-kDa glycoprotein is the beta-subunit of the gastric H+/K+ ATPase. We conclude that the monoclonal antibodies specifically recognise luminal epitopes on the 35-kDa core protein of the 60-90-kDa beta-subunit of the gastric proton pump, a major target molecule in autoimmune gastritis and pernicious anaemia. These monoclonal antibodies will be valuable probes to study the structure and function of this associated beta-subunit, as well as the ontogeny of the gastric proton pump.

Involvement of Bone Morphogenetic Protein-4 (BMP-4) and Vgr-1 in morphogenesis and neurogenesis in the mouse

Bone Morphogenetic Protein-4 (BMP-4) and Vgr-1 are members of the TGF-beta gene family most closely related to the Drosophila Decapentaplegic and Xenopus Vg-1 genes. Members of this gene family have been implicated in diverse processes during embryogenesis including epithelial-mesenchymal interactions. Here, we use in situ hybridization to localize BMP-4 and Vgr-1 transcripts during murine development. BMP-4 mRNA is found in a variety of tissues. In the 8.5 days p.c. embryo, transcripts are localized to the mesoderm posterior to the last somite. Later gestation embryos show expression in developing limbs, the embryonic heart, the facial processes and condensed mesenchymal cells associated with early whisker follicle formation. In the developing central nervous system (CNS), BMP-4 expression is restricted to the floor of the diencephalon associated with pituitary development. In contrast, Vgr-1 transcripts are found along the anteroposterior axis of the CNS, in cells immediately adjacent to the floor plate and in the roof plate extending to the forebrain. Together, the data support the hypothesis that polypeptide growth factors of the TGF-beta superfamily play key roles in the initial stages of neurogenesis and organogenesis during murine development.