Mutation and deletion of the pseudoautosomal gene SHOX cause Leri-Weill dyschondrosteosis.

Leri-Weill Dyschondrosteosis (LWD; OMIM 127300) is a dominantly inherited skeletal dysplasia characterized by disproportionate short stature with predominantly mesomelic limb shortening. Expression is variable and consistently more severe in females, who frequently display the Madelung deformity of the forearm (shortening and bowing of the radius with dorsal subluxation of the distal ulna). The rare Langer Mesomelic Dysplasia (LD; OMIM 249700), characterized by severe short stature with hypoplasia/aplasia of the ulna and fibula, has been postulated to be the homozygous form of LWD (refs 4-6). In a six-generation pedigree with LWD, we established linkage to the marker DXYS6814 in the pseudoautosomal region (PAR1) of the X and Y chromosomes (Z max=6.28; theta=0). Linkage analysis of three smaller pedigrees increased the lod score to 8.68 (theta=0). We identified submicroscopic PAR1 deletions encompassing the recently described short stature homeobox-containing gene SHOX (refs 7,8) segregating with the LWD phenotype in 5 families. A point mutation leading to a premature stop in exon 4 of SHOX was identified in one LWD family.

A homeobox gene, HLXB9, is the major locus for dominantly inherited sacral agenesis.

Partial absence of the sacrum is a rare congenital defect which also occurs as an autosomal dominant trait; association with anterior meningocoele, presacral teratoma and anorectal abnormalities constitutes the Currarino triad (MIM 176450). Malformation at the caudal end of the developing notochord at approximately Carnegie stage 7 (16 post-ovulatory days), which results in aberrant secondary neurulation, can explain the observed pattern of anomalies. We previously reported linkage to 7q36 markers in two dominantly inherited sacral agenesis families. We now present data refining the initial subchromosomal localization in several additional hereditary sacral agenesis (HSA) families. We excluded several candidate genes before identifying patient-specific mutations in a homeobox gene, HLXB9, which was previously reported to map to 1q41-q42.1 and to be expressed in lymphoid and pancreatic tissues.

Heterozygous mutations in the gene encoding noggin affect human joint morphogenesis.

The secreted polypeptide noggin (encoded by the Nog gene) binds and inactivates members of the transforming growth factor beta superfamily of signalling proteins (TGFbeta-FMs), such as BMP4 (ref. 1). By diffusing through extracellular matrices more efficiently than TGFbeta-FMs, noggin may have a principal role in creating morphogenic gradients. During mouse embryogenesis, Nog is expressed at multiple sites, including developing bones. Nog-/- mice die at birth from multiple defects that include bony fusion of the appendicular skeleton. We have identified five dominant human NOG mutations in unrelated families segregating proximal symphalangism (SYM1; OMIM 185800) and a de novo mutation in a patient with unaffected parents. We also found a dominant NOG mutation in a family segregating multiple synostoses syndrome (SYNS1; OMIM 186500); both SYM1 and SYNS1 have multiple joint fusion as their principal feature. All seven NOG mutations alter evolutionarily conserved amino acid residues. The findings reported here confirm that NOG is essential for joint formation and suggest that NOG requirements during skeletogenesis differ between species and between specific skeletal elements within species.

A novel acropectoral syndrome maps to chromosome 7q36.

F syndrome (acropectorovertebral syndrome) is a dominantly inherited skeletal dysplasia affecting the hands, feet, sternum, and lumbosacral spine, which has previously been described in only two families. Here we report a six generation Turkish family with a related but distinct dominantly inherited acropectoral syndrome. All 22 affected subjects have soft tissue syndactyly of all fingers and all toes and 14 also have preaxial polydactyly of the hands and/or feet. In addition, 14 have a prominent upper sternum and/or a blind ending, inverted U shaped sinus in the anterior chest wall. Linkage studies and haplotype analysis carried out in 16 affected and nine unaffected members of this family showed that the underlying locus maps to a 6.4 cM interval on chromosome 7q36, between EN2 and D7S2423, a region to which a locus for preaxial polydactyly and triphalangeal thumb-polysyndactyly has previously been mapped. Our findings expand the range of phenotypes associated with this locus to include total soft tissue syndactyly and sternal deformity, and suggest that F syndrome may be another manifestation of the same genetic entity. In mice, ectopic expression of the gene Sonic hedgehog (Shh) in limb buds and lateral plate mesoderm during development causes preaxial polydactyly and sternal defects respectively, suggesting that misregulation of SHH may underlie the unusual combination of abnormalities in this family. A recently proposed candidate gene for 7q36 linked preaxial polydactyly is LMBR1, encoding a novel transmembrane receptor which may be an upstream regulator of SHH.

A locus for asphyxiating thoracic dystrophy, ATD, maps to chromosome 15q13.

Asphyxiating thoracic dystrophy (ATD), or Jeune syndrome, is a multisystem autosomal recessive disorder associated with a characteristic skeletal dysplasia and variable renal, hepatic, pancreatic, and retinal abnormalities. We have performed a genome wide linkage search using autozygosity mapping in a cohort of four consanguineous families with ATD, three of which originate from Pakistan, and one from southern Italy. In these families, as well as in a fifth consanguineous family from France, we localised a novel ATD locus (ATD) to chromosome 15q13, with a maximum cumulative two point lod score at D15S1031 (Zmax=3.77 at theta=0.00). Five consanguineous families shared a 1.2 cM region of homozygosity between D15S165 and D15S1010. Investigation of a further four European kindreds, with no known parental consanguinity, showed evidence of marker homozygosity across a similar interval. Families with both mild and severe forms of ATD mapped to 15q13, but mutation analysis of two candidate genes, GREMLIN and FORMIN, did not show pathogenic mutations.

Physical map of a 1.5 mb region on 12p11.2 harbouring a synpolydactyly associated chromosomal breakpoint.

Synpolydactyly (SPD) is a rare malformation of the distal limbs known to be caused by mutations in HOXD13. We have previously described a complex form of SPD associated with synostoses in three members of a Belgian family, which co-segregates with a t(12;22)(p11.2;q13.3) chromosomal translocation. The chromosome 12 breakpoint of this translocation maps to 12p11.2 between markers D12S1034 and D12S1596. Here we show that a mutation in the HOXD13 gene is not responsible for the phenotype, and present a physical map of the region around the 12p11.2 breakpoint. Starting from D12S1034 and D12S1596, we have established a contig approximately 1.5 Mb in length, containing 13 YAC clones, 16 BAC clones, and 11 cosmid clones. FISH analysis shows that cosmid LL12NCO1-149H4 maps across the breakpoint, and Southern blot experiments using fragments of this cosmid as probes identify a rearranged BamHI fragment in the patients carrying the translocation. A search for expressed sequences within the contig have so far revealed one CpG island, seven anonymous ESTs and three previously characterised genes, DAD-R, KRAG and HT21, all of which were found not to be directly disrupted by the translocation. The gene represented by EST R72964 was found to be disrupted by the translocation. These findings lay the groundwork for further efforts to characterise a gene critical for normal distal limb development that is perturbed by this translocation.

Evaluation of rotenone and related compounds as antagonists of slow-reacting substance of anaphylaxis.

Rotenone (1), dihydrorotenone (2), isorotenone (3), mutarotenone (4), and deguelin (12) were found to be potent antagonists of slow-reacting substance of anaphylaxis (SRS-A) in vitro. However, these compounds were also shown to inhibit histamine, serotonin, and acetylcholine at only ten times their IC50 concentrations for SRS-A antagonism. Rotenone (1) and several related compounds were also evaluated in an in vivo guinea pig anaphylaxis model. Several of these compounds and FPL 55712 (I) were effective in prolonging collapse times of animals which received an aerosol challenge of an antigen to which they had been sensitized.

Two cases with interstitial deletions of chromosome 2 and sex reversal in one.

We present two children with de novo interstitial deletions of the long arm of chromosome 2 (karyotypes 46,XY, del(2)(q31.1q31.3) and 46,XY, del(2)(q24.3q31.3), respectively). The first child had severe learning difficulties, growth retardation, unilateral ptosis, small palpebral fissures, a cleft uvula, and bilateral cutaneous syndactyly of the second and third toes. Despite her male karyotype, she had female external genitalia with hypoplasia of the clitoris and labia minora. This is the first reported case of feminization of the external genitalia in a genotypic male with an interstitial deletion of chromosome 2q31 and adds to the growing amount of evidence for a gene involved in sex determination in this chromosome region. The second child had severe mental and growth retardation, ptosis, down-slanting palpebral fissures, low-set ears, micrognathia, finger camptodactyly, and brachysyndactyly of the second to fifth toes. The clinical manifestations associated with deletions of 2q31 to 2q33 are similar to those found with proximal deletions at 2q24 to 2q31 and of band 2q24, suggesting that the phenotype may result from haploinsufficiency for one or more genes located at 2q31. Microsatellite marker studies showed that both children had paternally derived deletions that included the HOXD gene cluster and the EVX2, DLX1, and DLX2 genes known to be important in limb development.

Acromelic frontonasal dysostosis.

We report on 3 male and 2 female infants with acromelic frontonasal dysostosis. All 5 had a frontonasal malformation of the face and nasal clefting associated with striking symmetrical preaxial polysyndactyly of the feet and variable tibial hypoplasia. In contrast, the upper limbs were normal. This rare variant of frontonasal dysplasia may represent a distinct autosomal-recessive disorder. We suggest that the molecular basis of this condition may be a perturbation of the Sonic Hedgehog (SHH) signalling pathway, which plays an important part in the development of the midline central nervous system/craniofacial region and the limbs.

Differential calcium movements induced by agonists in guinea pig tracheal muscle.

The effects of high potassium, carbachol and histamine on tension responses and 45Ca fluxes in tracheal smooth muscle were examined. Calcium depletion or nitrendipine (10(-8) M) inhibited potassium-induced contractile responses more than those obtained with either histamine or carbachol, whereas Sr2+ inhibited mainly responses to histamine or carbachol. The Ca2+ entry facilitator, CGP 28392 (3 X 10(-6) M), potentiated contractions induced only by potassium. Uptake of 45Ca in guinea pig tracheal muscle can be separated into high and low affinity components. The 45Ca efflux rate from tracheal muscle into a La3+-substituted solution was over four-fold higher than in other smooth muscles. Potassium, carbachol and histamine induced sustained increases in 45Ca efflux into solutions containing 1.5 mM Ca2+; only transient increases in 45Ca efflux with carbachol and histamine were obtained after Ca2+ depletion. These agonists elicit contractile responses in tracheal muscle by selectively mobilizing different cellular and extracellular Ca2+ components.

Two per cent glutaraldehyde: a disinfectant in arthroscopy and arthroscopic surgery.

Arthroscopes and some instruments for arthroscopic surgery were prepared for use by soaking them for fifteen minutes in a cold solution of 2 per cent glutaraldehyde. This method was practical, economical, safe, and effective. Over a eight-year period we performed 12,505 arthroscopic procedures with an infection rate of 0.04 per cent. Although technically classified as a disinfectant, 2 per cent glutaraldehyde used under these conditions proved to be an effective method of preparing arthroscopic surgical instruments and was less damaging to these instruments than methods involving sterilization by steam.

Efficacy of an amitraz-impregnated collar in preventing transmission of Borrelia burgdorferi by adult Ixodes scapularis to dogs.

OBJECTIVE: To determine whether an amitraz-impregnated collar could prevent transmission of Borrelia burgdorferi by Ixodes scapularis to dogs. DESIGN: Laboratory trial. ANIMALS: 8 specific-pathogen-free Beagles. PROCEDURE: On days -15 and -1, all dogs had negative ELISA results for serum antibodies against B. burgdorferi. On day 0, 4 dogs were each fitted with an amitraz-impregnated (9%) collar, and 4 dogs served as untreated controls. On day 7, all dogs were infested with 100/scapularis (approx 50 females and 50 males) with a known B. burgdorferi infectivity rate of 39.4%. On days 21, 28, 35, 42, 56, 70, and 84, each dog was tested for serum antibodies against B. burgdorferi via ELISA and a western blot technique. Additional ELISA were also performed for serum antibodies against antigenically similar organisms. RESULTS: By day 70, all control dogs had developed serum ELISA responses ranging from 328 to 510 kinetics-ELISA units (equivalent to end-point titers of approx 43,500 to 60,000), whereas treated dogs remained seronegative throughout the study. Western blot assays performed on all serum samples confirmed that antibodies detected in control dogs reflected responses to specific antigens of B. burgdorferi, whereas treated dogs had no such antibodies. Additional serologic analyses confirmed that antibody responses observed in control dogs were not attributable to antigenically similar organisms. CONCLUSIONS AND CLINICAL RELEVANCE: Amitraz-impregnated collars prevented transmission of B. burgdorferi in 4 of 4 treated dogs and may be a useful management tool for prevention of borreliosis in dogs.

Evaluation of in vitro activity of two topical products against three organisms isolated from canine referral patients with otitis externa and cutaneous pyoderma.

Canine otitis externa and cutaneous pyoderma are common problems that are often associated with Staphylococcus intermedius, Pseudomonas aeruginosa, and Malassezia pachydermatis. In vitro activity of two topical products against these organisms isolated from canine referral patients were evaluated. Organisms were grown and diluted to a concentration equivalent to 10(7) colony-forming units (CFU) per mL and exposed to either a 0 or 1/5 dilution of Hexadene Flush with Spherulites (Virbac Animal Health Inc, Fort Worth, TX) or a 1/5 or 1/25 dilution of ResiCHLOR Lotion with Spherulites (Virbac Animal Health Inc, Fort Worth, TX) at time intervals from 1 to 30 minutes. Results showed that all three organisms were killed within 1 minute of contact time at 0 and 1/5 dilution of the flush. The lotion diluted to 1/5 also killed all three organisms. At 1/25 dilution, this lotion killed S. intermedius and P. aeruginosa within 1 minute of contact time, whereas M. pachydermatis was killed after 1 minute. The findings suggest that the two topical products exhibit efficacy against these common skin pathogens in vitro and can be useful in their clinical management.

How easy is it to contact the duty medical doctor responsible for acute admissions?

OBJECTIVE: To ascertain ease or difficulty of contacting duty junior doctors responsible for acute medical admissions by telephone. DESIGN: Telephone survey of hospitals in six health regions in England and Wales. SETTING: 70 Randomly selected hospitals, 15 of which were excluded because of non-acceptance of acute medical admissions. PARTICIPANTS: 71 Duty doctors (duty house physicians, senior house officers, or registrars responsible for acute medical admissions) in 48 hospitals; seven duty doctors in seven hospitals were excluded (four declined to participate and three required a written explanation of the survey). 67 Doctors gave full information to all questions. MAIN OUTCOME MEASURES: Time taken for hospital switchboards and duty doctors to reply to telephone call, diagnoses of patients recently admitted, and on call rotas and hours of sleep of duty doctors. RESULTS: Hospital switchboards responded within 30 seconds in 87 (74%) calls, and in 76 calls (64%) the duty doctor requested was contacted within a further two minutes. Chest pain, possibly due to myocardial infarction, was the most common reason for acute medical admissions. Nearly half (48%) of the duty doctors in larger hospitals reported having 4-5 hours sleep or less on their nights on call. Most (30) were on a one in three rota; two were on a one in two rota. CONCLUSIONS: Despite impressions to the contrary contacting the duty medical team by telephone seemed fairly easy. Although most junior doctors were on a rota of one in three or better, insufficient recognition may be given to their deprivation of sleep during nights on duty.