Secretion of glycosylation site mutants can be rescued by the signal/pro sequence of tissue plasminogen activator

Strategies that prevent the attachment of N-linked carbohydrates to nascent glycoproteins often impair intracellular transport and secretion. In the present study, we describe a method to rescue the intracellular transport and secretion of glycoproteins mutagenized to delete N-linked glycosylation sites. Site-directed mutagenesis was used to delete N-linked glycosylation sites from a chimeric protein, TNFR-IgG1. Deletion of any of the three glycosylation sites in the TNFR portion of the molecule, alone or in combination, resulted in a moderate or near total blockade of TNFR-IgG1 intracellular transport and secretion. Pulse chase experiments suggested that the glycosylation site mutants accumulated in the endoplasmic reticulum (ER) and were inefficiently exported to the Golgi apparatus (GA). Replacement of the TNFR signal sequence with the signal/pro sequence of human tissue plasminogen activator (tPA) overcame the blockade to intracellular transport, and restored secretion to levels comparable to those achieved with the fully glycosylated molecule. Ligand binding studies suggested that the secreted glycosylation variants possessed binding characteristics similar to the fully glycosylated protein. This study demonstrates that N-terminal sequences of tPA are unexpectedly efficient in facilitating transport from the ER to the GA and suggests that these sequences contain a previously unrecognized structural element that promotes intracellular transport.

Intensification regimen 2 for advanced head and neck squamous cell carcinomas

OBJECTIVE

To determine the feasibility, toxicity, and compliance of an intense treatment regimen for patients with advanced, previously untreated, resectable head and neck squamous cell carcinomas.

DESIGN

Prospective, nonrandomized, controlled (phase 1 or 2) clinical trial; median time at risk, 25 months (range, 7 days to 36 months).

SETTING

Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, The Ohio State University, Columbus.

PATIENTS

Forty-three patients (median age, 59 years; range, 32-76 years) with resectable, previously untreated stage III or IV squamous cell carcinomas of the oral cavity, oropharynx, or hypopharynx or stage II squamous cell carcinomas of the hypopharynx (referred sample of patients).

INTERVENTIONS

Days 1 to 4, perioperative, slightly accelerated, hyperfractionated radiotherapy (9.1 Gy) to off cord fields; days 1 to 3, cisplatin, 30 mg/m2 per day; day 4, surgical resection and intraoperative radiotherapy boost (7.5 Gy); days 45 to 52, postoperative radiotherapy (40 Gy to the primary site and upper neck and 45 Gy to the supraclavicular areas); days 24, 45, and 66, paclitaxel, 135 mg/m2 per 24 hours, with routine granulocyte colony-stimulating factor support; and days 25 and 46, cisplatin, 100 mg/m2.

MAIN OUTCOME MEASURES

Toxicity, compliance, local control, and distant metastatic rates.

RESULTS

Patient compliance was 91% (39 of 43 patients), but protocol compliance was only 58% (25 of 43 patients), reflecting increased toxicity of the systemic regimen (2 [5%] of the 43 patients experienced grade 5 hematologic toxicity due to the regimen; 16 [37%], grade 4; and 10 [23%], grade 3). Local-regional control was 92% (23 of 25 patients), and the distant metastatic rate was 8% (2 of 25) in patients completing treatment per protocol. One patient had surgical salvage of a second primary tumor.

CONCLUSIONS

Local control and patient compliance were encouraging, but systemic toxicity was unacceptable. Thus, the paclitaxel was changed to a weekly regimen.

Monitoring the clearance of fetal RhD-positive red cells in FMH following RhD immunoglobulin administration

Anti-RhD immunoglobulin was administered to RhD-negative women based on estimates of fetal bleed size obtained using a direct immunofluorescence flow cytometric technique employing a FITC-conjugated monoclonal human anti-D (BRAD 3). The effectiveness of the dose administered was assessed by (i) measuring the fraction of RhD-positive fetal cells in the maternal circulation at d0, and between d2 and d10 post RhD Ig administration, (ii) quantifying the amount of anti-D detectable in maternal plasma following RhD Ig injection in the perinatal period and (iii) assessing maternal serum for the presence of immune anti-D in follow-up samples taken 3 months to 3 years after delivery. Fifty-four women were assessed, 29 having fetal bleeds in excess of 4 mL. Follow-up samples were received from 20/29 mothers after RhD Ig administration; 43-99% and 69-99% of fetal cells had been cleared by d2/3 and d5/6, respectively, in 14/20 mothers, whereas less than 50% had been cleared in the remaining mothers. Long-term follow-up samples were obtained from eight of the 29 mothers (four with bleeds >/=20 mL, two with bleeds >95 mL): none had detectable anti-D in the serum 4 months to 3 years after delivery despite the persistence of up to 36% fetal RhD-positive cells in the maternal circulation six days after delivery.

Crystal structure at 1.63 A resolution of the native form of porcine beta-trypsin: revealing an acetate ion binding site and functional water network

The active center of a serine protease is the catalytic triad composed of His-57, Ser-195 and Asp-102. The existing crystal structure data on serine proteases have not fully answered a number of fundamental questions relating to the catalytic activity of serine proteases. The new high resolution native porcine beta-trypsin (BPT) structure is aimed at extending the knowledge on the conformation of the active site and the ordered water structure within and around the active site. The crystal structure of BPT has been determined at 1.63 A resolution. An acetate ion bound at the active site of a trypsin molecule by both classical hydrogen bonds and C-HellipsisO hydrogen bonds has been identified for the first time. A large network of water molecules extending from the recognition amino acid Asp-184 to the entry of the active site has been observed in the BPT structure. A detailed comparison with inhibitor complexes and autolysates indicates that the sulfate ion and the acetate ion bind at the same site of the trypsin molecule. The Ser-195 Cbeta-Ogamma-His-57 Nepsilon angle in the catalytic triad of BPT is intermediate between the corresponding values of the complex and native structure due to acetate ion binding. The network of waters from the recognition amino acid to the active site entry is probably the first ever complete picture of functional waters around the active site. Structural comparisons show that the functional waters involved in the binding of small molecule inhibitors and protease inhibitors are distinctly different.

Identification of a putative regulatory subunit of a calcium-activated potassium channel in the dup(3q) syndrome region and a related sequence on 22q11.2

Duplication of a segment of the long arm of human chromosome 3 (3q26.3-q27) results in a syndrome characterized by multiple congenital abnormalities and neurological anomalies in some patients. We have identified a novel gene (KCNMB3) that maps to this region. KCNMB3 has significant sequence similarity to the regulatory subunit of the large-conductance calcium-activated potassium channel. Due to the significance of potassium channels in neuronal functions, the overexpression of this gene may play a role in the abnormal neurological functions seen in some of these patients. A related sequence corresponding to the second and third exons of this gene resides in the pericentromeric region of 22q11, where a number of other unprocessed pseudogenes are known to map.

Distribution of mesothelioma cases in different occupational groups and industries in Australia, 1979-1995

Australia was a producer and user of asbestos and has one of the highest national incidences of mesothelioma in the world. The incidence is still rising and expected to do so for another 10-20 years. A study was conducted in 1996 to examine the past and current incidence rates of mesothelioma in a number of industries and occupations as the basis for predicting future outcomes. Occupational histories of a total of 3758 mesothelioma cases collected by two sequential national schemes--the Australian Mesothelioma Surveillance Program (1979-1985) and Australian Mesothelioma Register (1986-1995)--were reviewed and coded by the authors. The building industry contributed the largest number of cases nationwide followed by shipbuilding and repair, asbestos cement production, crocidolite mining and milling, railway locomotive construction and repair, coal-fired power stations, and other engineering operations. The mean latency between initial occupational asbestos exposure and diagnosis of the disease was 37.4 years (range = 4-66 years) for cases notified between 1979 and 1985, and 41.4 years (range = 6-84 years) for those between 1986 and 1995. Trends for each industry group have been changing considerably in the past 16 years, with the traditional primary asbestos industry cases from crocidolite mining and milling now on the decline and cases from asbestos cement production having plateaued. In contrast, more recently, more cases were observed from the asbestos user industries such as the building industry, and from occupations such as plumbers, carpenters, machinists, and car mechanics. These increases might be a reflection of the longer latency effects of the intermittent and less severe exposures in these larger occupational groups.

Information before coronial necropsy: how much should be available?

AIM

To assess the amount and quality of information supplied before undertaking a coroner's necropsy, based on the supposition that insufficient information may adversely affect the quality of the necropsy.

METHODS

For a one year period (947 cases), sudden death reports from the coronial jurisdiction of South Yorkshire (West) were audited to assess the quality of information supplied. Seven specific items of information were sought: age, sex, occupation, date of death, location of the body, position of the body, date of last seeing a general practitioner, and relevant medical history. The results from necropsy and non-necropsy cases were compared.

RESULTS

Only 22.1% of reports contained all seven items of information. There was no difference between the amount of information supplied in necropsy and non-necropsy cases except about when the general practitioner last saw the deceased. An occupational history was not available in 40.4% of all deaths.

CONCLUSIONS

The quality of information supplied to the pathologist before necropsy may be suboptimal and could affect the thoroughness of the necropsy itself.

Variability of polymerase chain reaction detection of the bcl-2-IgH translocation in an international multicentre study

BACKGROUND

The capacity of the polymerase chain reaction (PCR) to detect very low numbers of cells bearing a t(14;18) translocation has led to its application in assessment of the results of treatment for follicular lymphoma, and suggestions that therapy might be guided by molecular studies. To test the reliability of PCR a collaborative study was undertaken to compare results from different laboratories in Europe and North America.

METHODS

Twenty laboratories with records of publication in molecular diagnostics were sent blood from normal donors with varying numbers of t(14;18)-bearing cells added from a cell line with a translocation in the major breakpoint region (MBR) of the bcl-2 gene. Samples contained 1000, 100, 10, 1 or 0 cells per ml of whole blood and were sent blinded in duplicate. PCR methodology varied widely, with the total number of amplification cycles between 30 and 70, and 13 different primers used for the MBR region. Twelve laboratories used nested PCR and eight single round amplification.

RESULTS

The sensitivity of nested and single round PCR was similar at 100 cells/ml but below this the nested method proved significantly more sensitive. The false positive rate was 28%, with 11 samples from 9 laboratories reported as positive when no t(14;18) cells were added. PCR product size and sequence analysis showed that false positives were due to contamination from cell-line DNA rather than background translocations in the donors. There was no significant difference in false positive rates between nested and single round techniques.

CONCLUSION

The polymerase chain reaction to detect bcl-2-IgH rearrangements is presently carried out with widely disparate results. Further effort is required to bring forward a standard PCR protocol which can be re-tested in different laboratories to improve accuracy and reproducibility. The application of quantitative techniques such as real-time PCR may resolve many of the problems presently encountered.

Selective termination for structural, chromosomal, and mendelian anomalies: international experience

OBJECTIVE

Our purpose was to evaluate the outcomes of selective termination for fetal anomalies at 8 centers with the largest known experiences worldwide.

STUDY DESIGN

Outcomes in 402 cases of selective termination in pregnancies with dizygotic twins from 8 centers in 4 countries were analyzed by year, gestational age at procedure, and indication. Reductions of fetuses were as follows: 2 to 1, n = 345; 3 to 2, 39; >/=4 to 2 or 3, n = 18. Potassium chloride was used in all procedures.

RESULTS

Selective termination resulted in delivery of a viable infant or infants in >90% of cases. Loss up to 24 weeks occurred in 7.1% of cases in which the final result was a singleton fetus and in 13.0% of cases in which the final result was twins. Loss was 6.6% as a result of structural abnormalities, 7.0% for chromosomal abnormalities, and 10% for mendelian abnormalities (difference not statistically significant). Loss rates for procedures were as follows: 9-12 weeks, 5.4%; 13-18 weeks, 8.7%; 19-24 weeks, 6.8%; and >/=25 weeks, 9.1% (difference not statistically significant). Mean gestational age at delivery was 35.7 weeks. No differences were seen in outcomes by maternal age. The rate of very early premature deliveries has fallen in recent years. There were no known cases of disseminated intravascular coagulation or serious maternal complications.

CONCLUSION

(1) Selective termination, in the most experienced hands, can be technically performed in all 3 trimesters with good outcomes in >90% of cases. (2) The previously observed increase in second- versus first-trimester losses has diminished. (3) Third-trimester procedures, where legal, can be performed with a good outcome for the surviving fetus.

Seizures during video-game play and other common leisure pursuits in known epilepsy patients without visual sensitivity

PURPOSE

Some individuals who are negative to flash/pattern sensitivity have been reported to experience seizures while exposed to video games. This study seeks to examine systematically whether exposure to video-game material is a risk factor for seizures in patients with chronic epilepsy without visual sensitivity.

METHODS

Two hundred and twelve chronic epilepsy patients participated in the study. All were negative to rigorous flash and pattern sensitivity testing. They were randomly allocated to a video game-playing session or to a period of leisure (involving reading, physical exercise, puzzles, etc.) and then alternated between these activities for a fixed total of eight 45-min periods while undergoing video-EEG monitoring. The study ceased if the participant experienced a clinical seizure.

RESULTS

Twenty-five of 212 subjects experienced a seizure while participating in the study. Thirteen seizures occurred during periods of video-game play, and 12 during alternative leisure.

CONCLUSIONS

We have not identified a greater risk of seizures in patients with (not visually sensitive) epilepsy during video-game play compared with other common leisure pursuits. Furthermore, we exposed a large population (212 patients) mostly with severe epilepsy, mainly drug reduced and some sleep deprived, to prolonged video game-playing without observing a significant excess number of seizures. This finding provides strong support for the hypothesis that seizures during video game play in the >95% of the epilepsy population without visual sensitivity are most likely to represent a chance occurrence, although, as always, each individual should be carefully assessed.

Teenage fertility and life chances

Teenage mothers and their children face poorer prospects in life than do women who delay motherhood until later in life. Moreover, patterns of early childbearing tend to be repeated in subsequent generations. Therefore, an understanding of the factors associated with early fertility is important for the prevention of adverse consequences. This paper uses data from the National Survey of Sexual Attitudes and Lifestyles to explore these associations. Early sexual intercourse is an important predictor of early fertility, as is poor educational attainment, although it is not clear to what extent pregnancy acts to thwart academic ambitions, or to what extent poor educational performance leads to a need to seek personal fulfilment in other than academic goals. Thus, interventions designed to influence age at first intercourse and to improve educational performance both have potential in terms of impacting on teenage pregnancy rates. Family background also exerts a powerful influence on teenage fertility. Young people for whom one or both parents are absent are more likely to become parents early in life. However, the most important factor of family life determining the chances of teenage motherhood appear to be the quality of communication about sexual matters with the home. In terms of outcomes, teenage mothers are more likely to live in social housing, are less likely to be in paid employment and have larger than average sized families. Certain areas of the country, notably the older, run-down industrial areas, have higher rates of teenage motherhood than the newer, more prosperous areas. Because most of these effects are independent of one another, there is potential merit in intervening to prevent unintended conception at several points in a young woman's life. Primary preventive efforts are needed to reduce the rates at which teenage pregnancy occurs in this country. Yet, if the cycle of deprivation that means the children of young mothers themselves enter parenthood early is to be broken, then efforts must also be made to mitigate the effects of teenage fertility for both mother and child.

CHOP versus MACOP-B in aggressive lymphoma--a Nordic Lymphoma Group randomised trial

BACKGROUND

The long-term survival of patients with advanced stage aggressive lymphoma has not improved significantly during the last twenty years. In a randomised trial, the efficacy of MACOP-B, a six-drug weekly chemotherapy regimen, was compared to CHOP, the current standard regimen, in terms of overall and failure-free survival, toxicity and health related quality of life.

PATIENTS AND METHODS

Four hundred five patients with aggressive lymphoma, stage II-IV, age 18-67, were randomised to receive either 12 weeks of MACOP-B or 8 courses of CHOP over 24 weeks. Special emphasis was put in the definition of Ann Arbor stage in extranodal disease. A subset of 95 patients also entered a quality of life study, based on the EORTC QLQ-C30.

RESULTS

Thirty-one patients were ineligible. Among the remaining 374 patients, the median age was 52 years. According to the age-adjusted International Prognostic Index, 37% were 'high-intermediate' or 'high-risk' patients. No difference could be demonstrated, either in overall survival (60% at five years in the MACOP-B group and 59% in the CHOP group) or in failure-free survival (47% at five years with MACOP-B and 44% with CHOP). In terms of quality of life, physical function and global quality of life were more impaired in patients receiving MACOP-B, who also exhibited more non-haematological toxicity.

CONCLUSION

No superiority of MACOP-B compared to CHOP could be demonstrated. CHOP remains the treatment of choice in low-risk patients. At present, intensified or experimental treatment should be reserved for high-risk disease.

Development and integration of an extended embryo culture program

OBJECTIVE

To study and evaluate a sequential, extended embryo culture system.

DESIGN

Prospective study.

SETTING

University-affiliated IVF clinic.

PATIENT(S)

All couples who were treated between October 1997 and July 1998.

INTERVENTION(S)

A standard human tubal fluid plus 10% serum substitute supplement (SSS) culture medium was used. The embryos were transferred to extended culture medium (S2 or G2) on day 3.

MAIN OUTCOME MEASURE(S)

Blastocyst formation and implantation and pregnancy rates.

RESULT(S)

Forty percent of the 20 donated cryopreserved embryos progressed to the blastocyst stage by day 6. Clinically, 7 (5.6%) of the 125 cycles did not result in a transfer. Blastocyst formation rates ranged from 33%-63% in the five study groups. Implantation rates ranged from 15%-52% and pregnancy rates ranged from 37%-75%.

CONCLUSION(S)

Extended culture to day 5 or 6 results in acceptable blastocyst formation rates, implantation rates, and pregnancy rates.

Dual energy X-ray absorptiometry assessment of fat mass distribution and its association with the insulin resistance syndrome

OBJECTIVE

To determine which dual energy X-ray absorptiometry (DXA)-derived indices of fat mass distribution are the most informative to predict the various parameters of the metabolic syndrome.

RESEARCH DESIGN AND METHODS

A total of 87 healthy men, 63 lean (% fat < or =26) and 24 obese (% fat >26), underwent DXA scanning to evaluate body composition with respect to the whole body and the trunk, leg, and abdominal regions from L1 to L4 and from L3 to L4. These regions were correlated with insulin sensitivity determined by the euglycemic-hyperinsulinemic clamp, insulin area under the curve after oral glucose tolerance test (AUC I); triglyceride; total, HDL, and LDL cholesterol; free fatty acids; and blood pressure. The analyses were performed in all subjects, as well as in lean and obese groups separately.

RESULTS

Among the various indices of body fat, DXA-determined adiposity in the abdominal cut at L1-4 level was the most predictive of the metabolic variables, showing significant relationships with glucose infusion rate ([GIR], mg kg(-1) lean body mass x min(-1)), triglyceride, and cholesterol, independent of total-body mass (r = -0.267, P<0.05; r = 0.316, P<0.005; and r = 0.319, P<0.005, respectively). Upon subanalysis, these correlations remained significant in lean men, whereas in obese men, only BMI and the amount of leg fat (negative relationship) showed significant correlations with triglyceride and cholesterol (r = 0.438, P<0.05; r = 0.458, P<0.05; r = -0.439, P<0.05; and r = -0.414, P<0.05, respectively). The results of a multiple regression analysis revealed that 47% of the variance in GIR among all study subjects was predicted by AUC I, fat L1-4, diastolic blood pressure (dBP), HDL, and triglyceride as independent variables. In the lean group, fat L1-4 alone accounted for 33% of the variance of GIR, whereas in obese men, AUC I and dBP explained 68% of the variance in GIR.

CONCLUSIONS

The DXA technique applied for the evaluation of fat distribution can provide useful information regarding various aspects of the insulin resistance syndrome in healthy subjects. DXA can be a valid, accurate, relatively inexpensive, and safer alternative compared with other methods to investigate the role of abdominal body fat distribution on cardiovascular risk factors.

The role of microsomal triglyceride transfer protein and dietary cholesterol in chylomicron production in diabetes

AIMS/HYPOTHESIS

The aim of this study was to examine factors involved in chylomicron production in the streptozotocin diabetic rat, our hypothesis being that the synthesis of the chylomicron is abnormal in diabetes.

METHODS

Diabetic rats (n = 20) were paired with control rats (n = 20). Cholesterol emulsion was given by gavage and the lymph duct was cannulated. Lymph was collected for 4 h. Chylomicrons were prepared from the lymph by ultracentrifugation. Lymph apolipoprotein B48 was isolated by gradient gel electrophoresis and quantified by densitometric scanning. Intestinal microsomal triglycerol transfer protein mRNA was measured by solution hybridisation nuclease protection, using a rat specific [32P]-labelled cRNA probe.

RESULTS

Serum triglyceride and cholesterol were greatly increased in diabetic compared with control animals (258 +/- 77 and 8.9 +/- 6.4 mg/ml vs 1.04 +/- 0.37 and 0.54 +/- 0.03 mg/ml, p < 0.0001). Lymph chylomicron triglyceride and cholesterol were also higher in diabetic rats (29.4 +/- 27.3 and 0.28 +/- 0.3 mg/h vs 16.8 +/- 10.6 and 0.18 +/- 0.09 mg/h, p < 0.05). Lymph chylomicron apo B48 was similar in the two groups. Intestinal microsomal triglycerol transfer protein mRNA was higher in the diabetic rats (12.6 +/- 3.2 vs 3.8 +/- 3.0 amol/microgram RNA, p < 0.0001) and there was a positive correlation between lymph triglyceride and microsomal triglycerol transfer protein mRNA in the whole group (r = 0.65, p < 0.01).

CONCLUSION/INTERPRETATION

The study shows that microsomal triglycerol transfer protein mRNA is raised in diabetes without an increase in apolipoprotein B48 in the lymph suggesting that microsomal triglycerol transfer protein regulates chylomicron triglyceride content but not particle number.

The fatty acid distribution in low density lipoprotein in diabetes

Atherosclerosis is commonly found in diabetes. There is an association between small dense low density lipoprotein (LDL) phenotype, which is more prevalent in the diabetic state, and atherosclerosis. Small dense LDL is more easily oxidised and it is possible that fatty acid compositional changes, particularly an increase in polyunsaturated fatty acids, could underlie this association. However, there is little information about fatty acids in the different LDL phenotypes in the literature. This study examined LDL subfraction composition in 18 non-insulin-dependent diabetic (NIDDM) patients and 11 control subjects. LDL was isolated and fractionated into LDL 1, 2 and 3 by density gradient ultracentrifugation. NIDDM patients had significantly more fatty acids in all LDL subfractions than control subjects (P<0.01). Palmitic and linoleic acid were significantly greater in all subfractions in the diabetic patients compared to control subjects (P<0.01) and palmitoleic and oleic acids were also greater in LDL1 and LDL2 in diabetic patients (P<0.01). We conclude that in NIDDM fatty acids are increased in all LDL subfractions and this may be the reason for the increased atherosclerosis in diabetes irrespective of phenotype.

The effect of surface treatments on the bond strength of a nonprecious alloy-ceramic interface

PURPOSE

The purpose of this study was to compare the effect of seven different alloy surface treatments on the bond strength of the porcelain-metal interface.

MATERIALS AND METHODS

Three layers of opaque porcelain and a measured thickness of dentin porcelain were applied to nickel-chromium alloy. A tensile bond strength test was used.

RESULTS

The alloy surface treatment that exhibited the highest bond strength was sandblast + surface grinding + sandblast + de-gas, whereas the alloy surface treatment that exhibited the lowest bond strength was sandblast + surface grinding + sandblast + steam cleaning + de-gas. There was a significant difference between the two methods (P < 0.05).

CONCLUSION

It was concluded that de-gassing the alloy prior to porcelain application increased the bond strength and excess surface grinding of the alloy reduced bond strength; steam cleaning the alloy surface prior to de-gassing and porcelain application also significantly reduced the bond strength.

The A1166C mutation in the angiotensin II type I receptor and hypertension in the elderly

1. Using a nested case-control study of 661 non-institutionalized elderly (> or = 60 years) residents of Dubbo, New South Wales, Australia, the aim of this study is to determine whether the A1166C polymorphism of the angiotensin II type I (AT1) receptor gene is associated with hypertension in the elderly. 2. Individuals were classified as isolated systolic hypertension (ISH, n = 146), systolic diastolic hypertension (SDH, n = 188), or normotensive, age- and sex-matched controls (n = 327). AA, CC and AC genotypes were determined using restriction fragment length polymorphism analysis of DNA generated by nested polymerase chain reaction. 3. A univariate analysis (chi 2) was complemented by a logistic regression analysis, facilitating adjustment for potential confounders. The unadjusted genotype and allele frequencies in ISH or SDH subjects did not differ significantly from the control subjects (chi 2 = 3.0, P = 0.55, 4 d.f.; chi 2 = 3.0, P = 0.23, 2 d.f., respectively). After adjustment for potential confounders neither genotype nor allele predicted ISH or SDH in this cohort. 4. From this study we conclude that the A1166C polymorphism of the AT1 receptor gene is not a marker for ISH nor for SDH in this large, elderly community sample.

Are doctors still failing to assess and treat asthma attacks? An audit of the management of acute attacks in a health district

This audit aimed to observe the management of acute asthma by primary and secondary care within a Health District. Asthma attacks occurring during the first 6 weeks of 1996 to patients between the ages of 3 and 74 years in Canterbury and Thanet District were notified by general practitioners, out-of-hours co-operatives and hospitals. Data were obtained retrospectively from the patient records. A total of 378 episodes was registered: 342 (90%) to primary care. Of these 234 (76% of patients aged 6 years or over) had a peak flow recorded; 114 (30%) were given emergency bronchodilation: oxygen was not used in primary care; 204 (54%) were given systemic steroids; and 43 (11%) were referred for hospital care of whom 36 were admitted. Of the attacks, 212 (69% of the patients aged 6 years or over) could be classified by percentage predicted peak flow and management compared to the Guidelines published by the British Thoracic Society. Twenty-eight patients presented with 'life-threatening' asthma: 20 (71%) were given emergency bronchodilation; oxygen was used in only two; 24 (86%) were given systemic steroids; and six (21%) were referred for admission. In their confidential enquiry into the asthma deaths the British Thoracic Society identified a failure to appreciate the severity of the attack, resulting in inadequate emergency treatment and delay in referring to hospital. These data suggest that, 15 years later, these problems may still exist.

Microsatellite instability is rare in rectal carcinomas and signifies hereditary cancer

We analysed microsatellite instability (MSI) in a consecutive series of 165 rectal carcinomas. Data on a personal and/or family history of cancer were collected from all patients and revealed metachronous cancer in 9 patients, 2 of whom had developed colorectal cancer, and a suspected familial aggregation of colorectal cancer in three families. Only three of the 165 (2%) rectal cancers showed MSI. The patients whose tumours displayed MSI had clinical histories suggesting hereditary cancer--a family history of colorectal cancer and/or synchronous colorectal cancers. Denaturing gradient gel (DGGE) analysis was used to screen the MSI+ patients for mutations in the hMLH1 and hMSH2 genes and revealed two new germline mutations; a 1 bp deletion in exon 10 of hMSH2 creating a premature stop-codon and a splice donor site mutation in intron 16 of hMLH1. Considering colorectal carcinomas as a group, MSI has been reported to occur in approximately 10-20% of the tumours and thus can not, per se be used for clinical detection of hereditary tumours. This study shows, however, that MSI is rare in rectal carcinomas and when present strongly suggests a hereditary predisposition for colorectal cancer development.

Airway hyperresponsiveness in anaesthetised guinea-pigs 18-24 hours after antigen inhalation does not occur with all intravenously administered spasmogens

Actively sensitised guinea-pigs were exposed to inhalation challenges with ovalbumin aerosol (macro- and microshock) and airway responsiveness to six intravenously administered spasmogens was evaluated 18 to 24 hr later in the anaesthetised animal. An increase in airway sensitivity was defined as a significant leftward shift of the dose-response curve when compared with saline-challenged control sensitized animals. After ovalbumin-macroshock (1% ovalbumin for 2 min. with mepyramine cover against fatal anaphylaxis), airway hyperresponsiveness was seen to 5-HT, the thromboxane A2-mimetic, U-46619, and bradykinin but not to methacholine, histamine or substance P. A similar pattern was seen after ovalbumin-microshock (0.010% ovalbumin for 60 min.), with induction of airway hyperreactivity to 5-HT and U-46619 but not methacholine or histamine. When the U-46619 dose-response curve was constructed following treatment of the animals with atropine (1 mg/kg, intravenously), airway hyperresponsiveness was no longer significant. As an index of airway inflammation, lung weights were significantly heavier in ovalbumin-challenged animals, than in saline-challenged controls. The results of this study with intravenously administered spasmogens does not support claims that ovalbumin-induced airway hyperreactivity in the guinea-pig is a 'non-specific' phenomenon.