Glomerular-specific imprinting of the mouse gsalpha gene: how does this relate to hormone resistance in albright hereditary osteodystrophy?

The gene for alpha-stimulating guanine-nucleotide binding polypeptide, Gnas, has been considered as a candidate for the imprinting effects ascribed to distal mouse Chromosome (Chr) 2. Its human homologue (GNAS1) appears, from clinical and biochemical studies of patients with Albright hereditary osteodystrophy, to be paternally imprinted. GNAS1 maps to 20q13, a region that shows linkage conservation with distal mouse Chr 2. We have mapped Gnas within the imprinting region on distal Chr 2 by linkage analysis. To establish if Gnas is imprinted, we have looked for expression differences in tissues taken from mice carrying maternal duplication/paternal deficiency for distal Chr 2 (MatDp2) and its reciprocal (PatDp2). RNA in situ hybridization revealed high levels of Gnas mRNA in glomeruli of PatDp2 embryos at late gestation and lower levels in glomeruli of MatDp2 embryos. These results strongly suggest that Gnas is maternally imprinted and suggest that the mouse gene may be imprinted in a manner opposite that predicted in human.

Optimal shape of the laryngeal mask cuff: the influence of three deflation techniques

A randomised, single-blinded, controlled trial was conducted to determine if a new laryngeal mask deflation tool offered any advantages over manual or free deflation. Ten laryngeal mask airways were tested and the deflation tool provided a significantly superior and more consistent shape than either hand manipulation or the free deflation, but did not offer any benefits in terms of residual volume. The deflator tool should encourage wider use of the standard recommended insertion technique. It can be used as a backup when manual deflation cannot provide the correct shape and may be useful for researchers studying laryngeal mask airway placement.

Health services market testing--the experience of the community services review team in British Forces Germany

During 1993-1995 the health services in British Forces Germany were subjected to a market testing process by which the primary, community and acute health services for the British Servicemen and women, their families and attached civilian staff, a population of 70,000, were put out to competitive tender with the then current provider, the Defence Medical Services, as one tenderer for the contract. This paper outlines the methodology developed by the Health Alliance Community Services Review team in formulating a successful bid. It is considered that the process outlined could be of value to those involved in future market tests, commissioning projects or performance improvement programmes.

Photoinactivation of bacteria. Use of a cationic water-soluble zinc phthalocyanine to photoinactivate both gram-negative and gram-positive bacteria

The photosensitization of microorganisms is potentially useful for sterilization and for the treatment of certain bacterial diseases. Until now, any broad spectrum approach has been inhibited because, although Gram-positive bacteria can be photoinactivated by a range of photosensitizers, Gram-negative bacteria have not usually been susceptible to photosensitized destruction. In the present work, it has been shown that the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, as well as the Gram-positive bacterium Enterococcus seriolicida, can be photoinactivated when illuminated in the presence of a cationic water-soluble zinc pyridinium phthalocyanine (PPC). The degree of photoinactivation is dependent on both the concentration of PPC and the illumination time. In contrast, the three bacteria are not photoinactivated by illumination in the presence of a neutral tetra-diethanolamine phthalocyanine (TDEPC) or negatively charged tetra-sulphonated phthalocyanine (TSPC). Uptake studies have revealed that the lack of activity of TSPC is due to the fact that it has very little affinity for any of the organisms. However, the issue appears to be more complex than simply the gross levels of cellular uptake, since TDEPC and PPC are both taken up by the organisms but only PPC shows activity. This indicates that the localization and subcellular distribution of the phthalocyanines may be a crucial factor in determining their cell killing potential. Further analysis of the uptake data has revealed a cell-bound photosensitizer fraction, which remains tightly associated after several washings, and another weakly bound fraction, which is removed by successive washings. Analysis of the cell killing curves, carried out after successive washings of E. coli exposed to PPC, has revealed that it is the tightly associated fraction that is involved in the photosensitization. Taken together with other data, these results suggest that cationic photosensitizers may have a broader application in the photoinactivation of bacterial cells than the anionic or neutral photosensitizers commonly used in photodynamic therapy.

A novel cDNA with homology to an RNA polymerase II elongation factor maps to human chromosome 5q31 (TCEB1L) and to mouse chromosome 11 (Tceb1l)

Few of the auxiliary factors that assist RNA polymerase II in the process of mRNA chain elongation have been identified. We have isolated a novel cDNA, Tceb1l, from mouse and human sources that encodes a 163-amino-acid protein and shows a significant level of identity with a recently identified RNA polymerase II transcription elongation factor, p15. Tceb1l is highly conserved throughout vertebrates and maps to mouse chromosome 11 and to the syntenic region of human chromosome 5q31. Tceb1l shows a restricted pattern of expression in the early mouse embryo, where it is absent from the neurectoderm; later Tceb1l is expressed in the caudal region of the neural tube, followed by widespread expression in many tissues, including the brain and spinal cord. These observations are consistent with Tceb1l being an RNA polymerase II elongation factor and suggest that Tceb1l/p15-like peptides may be a new family of proteins that influence RNA elongation.

Absence of mutations in the Gs alpha and Gi2 alpha genes in sporadic parathyroid adenomas and insulinomas

1. Activating mutations of the alpha-subunits of the Gs and Gi2 proteins give rise to the oncogenes gsp and gip2, respectively, which are found in a variety of endocrine tumours. 2. In this study the polymerase chain reaction and direct sequencing have been used to screen a small sample of parathyroid adenomas and insulinomas for these mutations. 3. No mutations were identified in nine insulinomas and 13 parathyroid adenomas screened for gsp, and 11 parathyroid adenomas and four insulinomas screened for gip2. In addition, two gastrinomas from patients with multiple endocrine neoplasia type 1 were found to be negative for both oncogenes. 4. This is the first report of screening for gip2 in parathyroid adenomas and gsp/gip2 in insulinomas, and it extends the range of tumours examined for these oncogenes.

Angioimmunoblastic lymphadenopathy with dysproteinemia and dermal T-cell lymphoma

BACKGROUND

T-cell receptor (TCR)-gamma gene rearrangements provide a specific clonal marker for T-cell malignancies of both the alpha beta and gamma delta varieties. A polymerase chain reaction (PCR)-based method was used in this study for investigation of clonal TCR-gamma gene rearrangements in a patient with a classical presentation of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) that subsequently progressed into an indolent form of dermal T-cell lymphoma.

METHODS

TCR gene rearrangements in patients with cutaneous T-cell lymphoma (CTCL) were examined using conventional Southern blot analysis and a newly developed PCR-based technique for clonal TCR gene rearrangements. The oligoprimers amplified rearranged V gamma and J gamma segments (including the N region) of the TCR-gamma gene, and PCR products were resolved using high resolution nondenaturing polyacrylamide gel electrophoresis.

RESULTS

The authors' results demonstrated good correlation between the two techniques in 10 patients with CTCL (9 patients with C beta and 1 patient with delta 2 rearrangements) and 10 control subjects. The PCR-based technique allowed the authors to detect the presence of an identical T-cell clone in all skin nodules, but not in the original lymph node affected by AILD.

CONCLUSIONS

This PCR-based method for detecting clonal TCR rearrangements is a highly sensitive and specific technique for detecting T-cell clones in fresh and paraffin embedded tissues. The presence of a T-cell clone in all skin nodules of this patient, but not in the original lymph node affected by AILD, confirms previous findings that in some cases of AILD, clonal T-cell expansion may not be detectable until a later stage of the disease.

On the photodynamic therapy action spectrum of zinc phthalocyanine tetrasulphonic acid in vivo

The photodynamic therapy (PDT) activity of zinc phthalocyanine tetrasulphonic acid in a rodent tumour model was shown to be critically dependent on the wavelength of the excitation laser light over a relatively small wavelength range. Thus the sensitizer showed a doubling of the PDT activity with fibrosarcoma LSBD1 in BDIX rats when the wavelength of the illuminant was displaced from 680 to 692 nm. Under these conditions, the sensitizer is approximately three times more effective than polyhaematoporphyrin, whereas previously it has been considered to be of low PDT activity. This wavelength effect is attributed to a red shift of the absorption spectrum of the sensitizer in cells compared with that in solution. Fluorescence excitation studies with sensitizer absorbed in mouse 3T3 fibroblast cells are consistent with such a red shift.

Expression of the dystrophin-related protein (utrophin) gene during mouse embryogenesis

The utrophin (UTRN) locus is the autosomal homologue of the DMD (Duchenne muscular dystrophy) gene and encodes a protein, utrophin which is thought to be upregulated in the absence of dystrophin. In this study the spatial and temporal expression of the UTRN gene has been examined during mouse embryogenesis and compared with that of the DMD gene. The patterns of expression of these two genes are very different. Whilst DMD is expressed largely in mesodermal derivatives such as cardiac and striated muscle, UTRN shows a more widespread distribution and is expressed in neural tube, tissues which originate from neural crest and a variety of other sites of non-neural origin. In early embryos UTRN transcripts initially accumulate in the mid-neural plate and thereafter in the caudal neural tube. UTRN mRNA then becomes abundant in a subset of neural crest cell derived tissues, in particular the spinal and facial ganglia and ossifying facial cartilages. UTRN is also expressed in a variety of other sites and organs such as the tendon primordia in the digits, the pituitary, thyroid and adrenal glands, cardiac muscle, kidney and lung, follicles of the vibrissae and the outflow tract of the heart. Several patterns of UTRN expression are apparent and we discuss the possibility that these can be ascribed to a family of mRNAs transcribed from the UTRN gene using alternative promoters.

Preoperative radiotherapy for initially inoperable extremity soft tissue sarcomas

The results and complications of a combination of preoperative radiotherapy and surgery in the treatment of 70 patients with large or fixed extremity soft tissue sarcomas are reported. Sixty-one patients were referred with a primary tumour and 9 had recurrences. Thirty-three patients had tumours in the thigh and 38 tumours were fixed to neighbouring structures. The mean preoperative dose was 53 Gy (range 21-75). Eleven patients received a postoperative boost to tumour site. Four patients received preoperative intra-arterial Adriamycin. Overall, 42 patients (60%) responded to the radiotherapy, 4 with complete tumour resolution. Eighty per cent of those receiving greater than or equal to 60 Gy responded and a significant correlation between 2 Gy equivalent dose and response was demonstrated (P less than 0.005). The degree of tumour necrosis was increased in 23 of 52 evaluable patients following radiotherapy, although there was no correlation with dose or clinical response. There have been eight local recurrences and 17 deaths after a median follow-up of 2 years. Tumour size less than 10 cm was the only significant factor in the development of local recurrence (P = 0.04). Thirty-six patients developed immediate postoperative complications: 9 major (13%), 13 moderate (19%) and 14 minor (20%). Increasing patient age was the only significant independent factor for the development of complications (P = 0.015). Preoperative radiotherapy will usually permit limb conservation of extremity sarcomas which otherwise would be inoperable or require amputation. However, the increased incidence of wound complications in older patients demands meticulous technique.

Severe pulmonary hypertension in Ullrich-Noonan syndrome

A 19 year old woman with Ullrich-Noonan syndrome presented with a six month history of progressive dyspnoea and cyanosis. Clinical features were suggestive of severe pulmonary hypertension. Cross sectional echocardiography showed pronounced right ventricular pressure overload with right ventricular hypertrophy. Cardiac catheterisation confirmed severe pulmonary hypertension. Attempts to reduce pulmonary artery pressure with calcium channel blockers were unsuccessful. The patient died shortly after investigation. Necropsy confirmed primary pulmonary hypertension.

Computer monitoring, capture and analysis of gas/liquid chromatograph traces

The work described here is effectively the computerization of a gas/liquid chromatograph of the pen recorder type using a BBC microcomputer. The output from the g.l.c. can be captured by the computer in accordance with a series of parameters. The sampling rate can be altered, as can an averaging facility to reduce noise, and a threshold level to eliminate the storage of irrelevant and space-consuming data. The unprocessed readings are initially stored on the computer's floppy disk, then later retrieved and cut into smaller sections to allow maximum resolution for on-screen analysis. In the main analysis stage of the system all processing is shown graphically on the computer monitor at all stages. The principal steps in analysis involve the mathematical modelling and elimination of the solvent peak, the fixing of the retention time for each subsequent peak and its disentangling from any following peaks, and finally the calculation of the area under each individual peak. Several alternative methods are made available for disentangling peaks, which can be tried successively on a single peak then each printed out with comments for comparison later. All readings and results in table form and screen dumps of all trace images are available via a dot matrix printer.