ARHGAP29 Mutation Is Associated with Abnormal Oral Epithelial Adhesions.

Nonsyndromic cleft lip and/or palate (NSCL/P) is a prevalent birth defect of complex etiology. Previous studies identified mutations in ARHGAP29 associated with an increased risk for NSCL/P. To investigate the effects of ARHGAP29 in vivo, we generated a novel murine allele by inserting a point mutation identified in a patient with NSCL/P. This single-nucleotide variation of ARHGAP29 translates to an early nonsense mutation (K326X), presumably resulting in loss-of-function (LoF). Embryos from Arhgap29K326X/+ intercrosses were harvested at various time points. No homozygous Arhgap29K326X animals were found in the 45 analyzed litters, assessed as early as embryonic day 8.5 (e8.5). Coronal sectioning of e13.5 and e14.5 heads revealed that 59% of Arhgap29K326X/+ mice ( n = 37) exhibited improper epithelial contact between developing oral structures, while none were observed in wild types ( n = 10). In addition, Arhgap29K326X/+ embryos exhibited a significantly higher percentage of maxillary epithelium in contact with mandibular epithelium. Immunofluorescent analyses of the periderm and oral adhesions revealed the presence of Arhgap29 in periderm cells. These cells were p63 negative, keratin 17 positive, and keratin 6 positive and present at sites of adhesion, although occasionally disorganized. Oral adhesions did not appear to impair palatogenesis, as all analyzed Arhgap29K326X/+ embryos showed confluent palatal mesenchyme and epithelium at e18.5 ( n = 16), and no mice were found with a cleft at birth. Collectively, our data demonstrate that ARHGAP29 is required for embryonic survival and that heterozygosity for LoF variants of Arhgap29 increases the incidence and length of oral adhesions at a critical time point during orofacial development. In conclusion, we validate the LoF nature of the human K326X mutation in vivo and reveal a previously unknown effect of Arhgap29 in murine craniofacial development.

Analysis of ovariectomy and estrogen effects on body composition in rats by X-ray and magnetic resonance imaging techniques.

Resistance of bone to fracture--bone strength--has been shown to depend on both the amount of bone and its architectural spatial organization. In vivo magnetic resonance (MR) techniques have the capability of imaging bone tissue, including the trabecular microarchitecture and the marrow composition. We have applied in vivo and ex vivo MR methods to the tibia in an ovariectomized rat model of osteoporosis. Specifically, in vivo high-resolution three-dimensional MR imaging and localized MRS were facilitated by specialized coils and high field magnets, resulting in enhanced sensitivity of detection. As a result, in vivo and ex vivo differences in marrow composition were found between sham-ovariectomized, ovariectomized, and ovariectomized animals treated with 17-beta-estradiol. Estrogen effects were detected in vivo 7 days after surgery (3 days into treatment) as a decrease in the tibial fat signal level. The in vivo effects of ovariectomy were observed 56 days after surgery as an increase in MR image fat signal level and spectral fat/water ratio in the proximal tibia. Ex vivo measurements of tibial marrow water signal discriminated clearly between the sham and ovariectomized groups and showed increased individual variations in the treatment group. Imaging further showed that the highest fat content is observed in the epiphysis. Computed tomography confirmed ovariectomy-induced loss of bone in the proximal tibial metaphysis compared with the sham group. This loss of cancellous bone with ovariectomy is consistent with the MR observations of increases in both fat and water in the metaphysis. These data showed that MR techniques complement X-ray techniques in the bone, water, and fat compositional analysis of the appendicular skeleton in response to ovariectomy and pharmacological treatment.

A photometric study of the standard Philadelphia (Ph1) translocation of chronic myeloid leukemia (CML).

A newly developed form of high resolution microscope photometry has been employed in a study of the relationships between the chromosomes involved in the standard Philadelphia (Ph1) translocation of chronic myeloid leukemia (CML). The intention of the investigation was to provide quantitative data on the relative amount of material exchanged between the No. 9 and No. 22 chromosomes. A marked consistency in the amount of material lost from the Ph1 was observed, and the balanced nature of the standard Ph1 translocation was confirmed. The data are also in accordance with the concept of a reciprocal exchange between the No. 9 and No. 22 chromosomes.

The association between typhoid carriage, typhoid infection and subsequent cancer at a number of sites.

It has been demonstrated that bacteria can produce the very potent carcinogens (N-nitroso compounds), from nitrite and suitable amines. It has been hypothesized that this can happen whenever a body site which is normally sterile becomes colonized by bacteria. If this is so then such chronic infections should result in an increased incidence of local cancers and also of cancers at some distant sites. To test this we studied the risk of cancer at various sites in a cohort of chronic carriers of Salmonella typhi/paratyphi. We have observed a greatly increased risk of cancers of the biliary tract and also of cancers of the colorectum, pancreas, lung and all sites. The results are discussed in terms of the hypothesis being tested.

Prevention of blastic crisis in Ph1-positive chronic myeloid leukemia.

Fourteen untreated patients with Ph1-positive myeloid leukaemia received combination chemotherapy consisting of blocks of doxorubicin, vincristine, cytosine arabinoside and 6-thioguanine. Significant karyotypic conversion occurred in six patients, the percentage of Ph1-positive cells in the bone marrow falling by at least 50%. Maintenance therapy comprised vincristine, busulphan, hydroxyurea, 6-mercaptopurine and dibromannitol in rotation. Reinduction therapy was administered when Ph1 positivity reverted to 100%. Karyotypic reconversion was achieved in three of four patients. After induction, chromosome analysis of the bone marrow was performed every 3-6 months to detect the appearance of aneuploid clones, the intention being to intensify therapy at that stage.

High incidence of haemorrhagic colitis due to Escherichia coli O157 in one Scottish town: clinical and epidemiological features.

Verotoxin-producing strains of Escherichia coli (VTEC), in particular serotype O157:H7, are now recognised as the major cause of haemorrhagic colitis and the haemolytic uraemic syndrome (HUS) in the U.K. and in North America, and increasingly so in other countries. Over a 3-year period (1989-1991), 16 cases of E. coli 0157 infection occurred in one town (Peterhead) in north-east Grampian. Four patients required admission to hospital, of whom three developed HUS. The bovine source of VTEC infection has now been clearly established with foodborne, waterborne, person-to-person and zoonotic transmission described. Despite extensive local enquiries, the source(s) of infection of the 16 cases in Peterhead was not established. Much still needs to be learned about the epidemiology, risk factors and long-term clinical sequelae of VTEC infection and HUS. Close collaboration between the medical and veterinary professions is of paramount importance in order to provide better understanding of the prevalence of E. coli O157 infection in cattle and the route(s) of transmission to humans.

Environmental risk factors for sporadic Escherichia coli O157 infection in Scotland: results of a descriptive epidemiology study.

The objective of the study was to obtain detailed descriptive epidemiological information on sporadic verocytotoxin-producing Escherichia coli O157 infection in Scotland in relation to transmission routes and host-related risk factors. Using a standardized questionnaire, the study was carried out throughout Scotland over an 18-month period from July 1992 and co-ordinated at the Communicable Diseases and Environmental Health (Scotland) Unit, Glasgow (CDEH(S)U). The subjects were laboratory-confirmed cases of Escherichia coli O157 infection, of whom 138 met the criteria for inclusion in the study. The most important findings were the high proportion of cases who had been exposed to environmental factors such as farm animals and/or their by-products; or who had participated in gardening or garden-play; or who had suspected or confirmed household water supply problems, prior to the onset of illness. The frequency and relative importance of environmental risk factors requires further quantification and study in order to assess where control measures can be directed most effectively. The implications for the NHS in preventing this crippling, life-threatening infection are considerable, not least in relation to hospitalization, dialysis and renal transplantation costs.

NMR microscopy of hydrating hydrophilic matrix pharmaceutical tablets.

NMR microscopy has been used to monitor the formation of the gel layer in hydrating hydrophilic polymer tablets. Such tablets are used in the controlled delivery of drugs, where it has been found that the rate and extent of the swelling of the outer gel layer critically influences the kinetics of drug release. Tablets were hydrated in distilled water at 37 degrees C and then imaged at discrete time intervals using a 500 MHz microscope. The growth of the gel layer was clearly observed in time sequences of radial and axial sections. Axial images showed some interesting dimensional changes, with the gel at the flat surface of the tablet developing a concave shape. This is probably a reflection of the occurrence of uni-axial stress relaxation as hydration proceeds. Diffusion- and T2-weighted images provided evidence that the water in the gel layer is more strongly bound close to the dry core of the tablet than at the more fully hydrated outer surface. In images of tablets containing diclofenac, disruption of the gel layer was shown to occur primarily from the flat surfaces of the tablet, whilst the distribution of particles could be seen in tablets doped with insoluble calcium phosphate.

Comparison of 5-fluorouracil pharmacokinetics following intraperitoneal and intravenous administration using in vivo 19F magnetic resonance spectroscopy.

Intrahepatic pharmacokinetic studies of 5-Fluorouracil (5 FU) metabolism following intravenous and intraperitoneal administration have been undertaken in four patients using in vivo 19F nuclear magnetic resonance spectroscopy. Following intravenous administration, 5 FU decayed with "half times" ranging from 5 to 17 min. There was considerable variation of 5 FU pharmacokinetics between patients following intraperitoneal administration. Peritoneal contamination by infused 5 FU was considered to be a significant problem in one patient. A technique for providing superficial signal suppression was therefore investigated and its efficacy for excluding signal from the peritoneal space has been demonstrated. Owing to the potential for contamination from peritoneal 5 FU, the accumulation of fluoro-beta-alanine (FBAL) is a more reliable indicator of drug catabolism than the measurement of unlocalized "hepatic" 5 FU. Rapid intrahepatic catabolism of 5 FU to FBAL was demonstrated in all patients. However, there was greater pharmacokinetic variation following intraperitoneal administration than following intravenous administration. Therapeutic implications of intravenous compared with intraperitoneal administration of 5 FU are discussed.

Epidemiological aspects of outbreaks of food-borne salmonellosis in Scotland between 1980 and 1989.

Between 1980 and 1989, 2,212 outbreaks of food-borne infection were reported in Scotland. Of 2,073 episodes for which a causative agent was established, 1,732 (84%) were caused by salmonellae. An average of 980 people were affected each year, while the average number of individuals infected per general outbreak was 16.8. The infected foods were consumed outside Scotland in 25% of the outbreaks. In 75% of 1,107 episodes where the location was specified, the implicated foods were consumed in the home; hotels and restaurants accounted for 15%. Specific food items were identified in 603 (35%) of the 1,732 outbreaks; poultry meat was responsible for 332 (55%) and milk 49 (8%), while eggs accounted for 23 (4%) outbreaks.

Interprofessional liaison in Scotland.

Communication between the medical, veterinary and environmental health professions has been established in Scotland since the early 1970s and was strengthened by the introduction of the Zoonoses Order 1975. The secondment of a veterinary officer to the Communicable Diseases (Scotland) Unit in Glasgow provides veterinary expertise on matters relating to public health, in addition to improving liaison, surveillance and the other functions of the unit.

Salmonella in sewage effluent and the relationship to animal and human disease in the north of Scotland.

During the period July 1982 to December 1984, the presence of salmonella organisms was investigated at weekly intervals in the sewage system and abattoir effluent of a town in the north of Scotland. Three hundred and fifteen isolations, representing 37 different serotypes, were made which included 20 different Salmonella typhimurium phage types and four different S enteritidis phage types. Ten of the serotypes were isolated from livestock in the district during the survey as well as in the periods immediately before and after the survey. There were seven recorded incidents of human infection, involving four salmonella serotypes, only three of which were isolated concurrently from sewage.

Milkborne salmonellosis in Scotland 1980 to 1982.

In Scotland between 1980 and 1982 there were 21 episodes of milkborne salmonella affecting a total of 1090 persons (range one to 654). There were eight deaths, including two children, in people associated with these outbreaks. The problem of milkborne salmonellosis continues to be greater in Scotland, where dairy herds on average are larger and a greater proportion of raw milk is consumed, than elsewhere in Britain. It is anticipated that legislation requiring the pasteurisation of virtually all milk sold for human consumption in Scotland by August 1983, will help to correct the situation.

Human and animal salmonellosis in Scotland associated with environmental contamination, 1973-79.

Twenty-six incidents of salmonellosis occurring in Scotland between 1973 and 1979 and attributed to environmental pollution are reviewed. The apparent sources of pollution were sewage effluent (10 incidents), septic tank effluent (eight), sewage sludge (three), seagulls (three) and abattoir effluents (two). Cattle were the species predominantly affected. Human infection was primary in three incidents and was secondary to bovine infection in another four. Thirteen salmonella serotypes were recovered from infected humans or animals and 17 during related environmental investigations. The factors causing pollutions and possible control measures are discussed.