Biomedical subjects
Publications and source records attributed to M Ward.
Two patients with diffuse cutaneous systemic sclerosis and spinal calcification, involving the lumbar spine in one and the cervical spine in the other, are described. Computed tomography-guided aspiration of the calcific masses was performed, and material aspirated from one patient was shown to be apatite, Ca5(PO4)3OH. One patient showed improvement following lumbar laminotomy, hemilaminectomy, and diskectomy.
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PURPOSE: Metachronous colorectal cancer still occurs in a small percentage of patients, despite colonoscopic surveillance. Cancers in hereditary nonpolyposis colorectal cancer for which there is a high risk of metachronous cancer show distinctive DNA changes termed replication errors (RER+). Ten to 20 percent of sporadic colorectal cancers are also RER+. The aim of this study was to identify factors predictive of metachronous colorectal cancer, despite colonoscopic surveillance. Clinicopathologic characteristics and RER status of cancers were examined. METHODS: Colorectal cancer patients, who entered into a surveillance program of being examined with colonoscopy within six months of surgery and then at intervals of three years thereafter, were reviewed. The 433 patients compliant with the protocol who had had more than one colonoscopy had been followed up for a mean of 3.8 +/- 2.2 years. DNA was extracted from archival paraffin-embedded cancer tissue for determination of RER status. RESULTS: Ten cases of metachronous cancer were identified, giving a rate of 0.61 percent per year. The site of the index cancer in patients who later developed metachronous cancer was predominantly proximal (P = 0.0007), and these cancers were more likely to have mucinous histology (P < 0.0005). Three of 10 (30 percent) index cancers were RER+, which was not significantly different from unselected series of control colorectal cancers in which 20 of 108 (18.5 percent) were RER+. DISCUSSION: This study documents the rate of metachronous cancer among patients compliant with a defined colonoscopic screening program and suggests that the risk is highest in patients with a proximal mucinous cancer. RER status does not appear to be a very strong predictive factor, and this study does not support its use as a guide to the frequency of surveillance colonoscopy. More data would be required to determine if RER positivity conferred a relative risk of 3.3 or less.
We evaluated the ability of mice made genetically deficient for B cells to resolve a primary infection and to develop protective immunity against vaginal challenge with a human isolate of Chlamydia trachomatis bacteria. The B-cell-deficient microMT mice cleared a primary ascending infection with similar or faster kinetics compared with wild-type mice. The presence of chlamydial inclusion bodies and the degree of inflammation in the upper genital tract was comparable and showed similar kinetics in microMT as in wild-type mice. Following resolution of the primary infection the mice were challenged by 100 ID50 of live bacteria and the level of protection and the extent of local inflammation was assessed. Strikingly, all microMT mice, as well as most of the wild-type mice, demonstrated complete immune protection with no bacterial shedding. While high titres of chlamydia-specific antibodies were stimulated locally and systemically in wild-type mice, no antibodies were detected in microMT mice. However, in both strains, immunohistochemical analysis of the upper genital tract demonstrated the presence of large numbers of CD4+ T cells and increased levels of interferon-gamma (IFN-gamma)-producing cells. The results unequivocally demonstrate that antibodies are not required for full protection to develop against ascending infection with a high dose of C. trachomatis in the female genital tract. Our study confirms the notion that cell-mediated immunity, in particular that owing to CD4+ T helper I (Th1)-type cells, is critical for host resistance against C. trachomatis in mice.
Chlamydia trachomatis is one of the major causes of infertility and preventable blindness in the world. The organism is of particular interest from an immunological point of view because it is one of the few obligate intracellular bacterial pathogens. There is some evidence that repeated infections in humans stimulate protective immunity. However, until recently, it was unclear which components of the adaptive immune system give rise to protection. Studies in gene knockout mice reported here and elsewhere now give a coherent and cogent picture of the importance of the Th1 response, in particular IFN-gamma, for the localization and eradication of C. trachomatis genital tract infection. The key questions still to be addressed are the identity of the IFN-gamma responsive cells and whether the mouse is truly representative of host protection against chlamydiae in humans.
Elevated plasma homocysteine, an independent risk factor for cardiovascular disease (CVD) can be lowered by administration of pharmacological doses of folic acid. The effect of lower doses in apparently normal subjects is currently unknown but is highly relevant to the question of food fortification. Healthy male volunteers (n = 30) participated in a chronic intervention study (26 weeks). Folic acid supplements were administered daily at doses increasing from 100 micrograms (6 weeks), to 200 micrograms (6 weeks), to 400 micrograms (14 weeks). Fasting blood samples collected before, during and 10 weeks post intervention were analysed for plasma homocysteine, serum and red-cell folate levels. Results, expressed as tertiles of baseline plasma homocysteine concentration, showed significant (p < or = 0.001) homocysteine lowering in the top (10.90 +/- 0.83 mumol/l) and middle (9.11 +/- 0.49 mumol/l) tertiles only. In the low tertile, where the mean baseline homocysteine level was 7.07 +/- 0.84 mumol/l, no significant response was observed. Of the three folic acid doses, 200 micrograms appeared to be as effective as 400 micrograms, while 100 micrograms was clearly not optimal. There is thus a minimal level of plasma homocysteine below which folic acid has no further lowering effect, probably because an optimal folate status has been reached. A dose as low as 200 micrograms/day of folic acid is effective in lowering plasma homocysteine concentrations in apparently normal subjects. Any public health programme for lowering homocysteine levels, with the goal of diminishing CVD risk, should not be based on unnecessarily high doses of folic acid.
The prevalence of Chlamydia trachomatis in the lower genital tract and amniotic fluid of women with preterm prelabour amniorrhexis was assessed by DNA amplification for C. trachomatis performed in cervical swabs and amniotic fluid obtained by amniocentesis. C. trachomatis was present in the cervix of 20 (23%) of the cases and in six (30%) of those the organism was also present in the amniotic fluid. There was no association with other pathogens in the lower genital tract or amniotic fluid. The presence of C. trachomatis was not associated with a significant decrease in the amniorrhexis to delivery interval or with an increase in perinatal mortality or morbidity.
CD4+ T cells have been found to play a critical role in immune protection against Chlamydia trachomatis infection. Since both humoral and cell-mediated antichlamydial immunity have been implicated in host protection, the crucial effector functions provided by the CD4+ T cells may rely on Th1 or Th2 functions or both. In the present study, we evaluated the development of natural immunity following vaginal infection with C. trachomatis serovar D in female gamma interferon receptor-deficient (IFN-gammaR-/-) mice with a disrupted Th1 effector system. We found that in comparison with wild-type mice, the IFN-gammaR-/- mice exhibited a severe ascending primary infection of prolonged duration which stimulated almost 10-fold-stronger specific local immunoglobulin A (IgA) and IgG responses in the genital tract. Following resolution of the primary infection and despite the augmented antibody responses to chlamydiae, the IFN-gammaR-/- mice were completely unprotected against reinfection, suggesting that local antibodies play a subordinate role in host protection against chlamydial infection. Immunohistochemical analysis of frozen sections of the genital tract revealed many CD4+ T cells in the IFN-gammaR-/- mice, with a dominance of interleukin 4-containing cells in mice following resolution of the secondary infection. However, in contrast to the findings with wild-type mice, the typical clusters of CD4+ T cells were not found in the IFN-gammaR-/- mice. Few and similarly distributed CD8+ T cells were observed in IFN-gammaR-/- and wild-type mice. Whereas chlamydia-infected macrophages from wild-type mice had no inclusion bodies (IB) and produced significant amounts of nitric oxide (NO) in the presence of IFN-gamma, macrophages from IFN-gammaR-/- mice contained many IB but no NO. These results indicate that CD4+ Th1 cells and IFN-gamma, rather than local antibodies, are critical elements in host immune protection stimulated by a natural ascending C. trachomatis infection in the female genital tract.
The Drosophila single-minded and trachealess bHLH-PAS genes control transcription and development of the CNS midline cell lineage and tracheal tubules, respectively. We show that Single-minded and Trachealess activate transcription by forming dimers with the Drosophila Tango protein that is an orthologue of the mammalian Arnt protein. Both cell culture and in vivo studies show that a DNA enhancer element acts as a binding site for both Single-minded::Tango and Trachealess::Tango heterodimers and functions in controlling CNS midline and tracheal transcription. Isolation and analysis of tango mutants reveal CNS midline and tracheal defects, and gene dosage studies demonstrate in vivo interactions between single-minded::tango and trachealess::tango. These experiments support the existence of an evolutionarily conserved, functionally diverse bHLH-PAS protein regulatory system.
For centuries, mountains have given rise to legends about supernatural beings such as the Yeti of the Himalayas. The legend of the Yeti was enhanced by the finding of footprints in the Menlung Basin during the 1951 Everest reconnaissance expedition. This report provides a possible explanation of the Menlung footprints based on developmental abnormalities, physiology, and pathology of the foot.
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To evaluate the role played by nitric oxide in global cerebral ischaemia we examined the effects of 7-nitroindazole and a sodium salt of 7-nitroindazole (inhibitors of neuronal nitric oxide (NO) synthase) and NG-nitro-L-arginine methyl ester (a more general inhibitor of NO synthase) in the gerbil model of cerebral ischaemia. Four experiments were carried out. In the first experiment, animals were either sham-operated, subjected to 5 min bilateral carotid occlusion (BCAO) or administered 7-nitroindazole or NG-nitro-L-arginine methyl ester immediately after occlusion followed by three further doses at 3, 6 and 24 h post-occlusion. In the second experiment, we examined the effects of a sodium salt of 7-nitroindazole, which is more soluble than 7-nitroindazole, using the same protocol. In the third experiment, the effects of the sodium salt of 7-nitroindazole administered at 10 mg/kg at 0, 3, 6, 24, 27, 30, 33, 52, 55, 72, 75 and 78 h post-occlusion or at 0.05 mg/h for 72 h via mini-pumps were evaluated. In separate experiments, we examined the effects of three reference compounds dizocilpine (MK-801), 2, 3-dihydroxy-6-nitro-7-sulphamoyl-benz(F)-quinoxaline (NBQX) and eliprodil using the same model. Extensive neuronal death was observed in the CA1 layer of the hippocampus in 5 min bilateral carotid occluded animals 5 days after surgery. Both 7-nitroindazole and NG-nitro-L-arginine methyl ester provided significant neuroprotection (P < 0.01) against this neuronal death. The sodium salt of 7-nitroindazole showed no protection when administered up to 12 times post-occlusion, but did provide significant (P < 0.01) neuroprotection when administered via mini-pump. The neuroprotection was similar to that provided by MK-801 and eliprodil, but not as good as that observed with NBQX. These results indicate that nitric oxide plays a role in ischaemic cell death and that selective neuronal nitric oxide synthase inhibitors can protect against ischaemic brain damage.
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From January 1969 to December 1992, mitral valve reconstructive operations were performed on 155 patients with degenerative mitral valve disease. There were 102 male and 53 female patients, with a mean age of 60.5 +/- 9.2 years, a mean duration of symptoms of 3.8 +/- 2.7 years, and 34% were in atrial fibrillation. All patients were in New York Heart Association functional classes III and IV before operation. The degree of mitral regurgitation was severe in 94% and moderate in 6%, and 50.9% of patients had moderate to severe impairment of left ventricular function. Emergency operation was undertaken in 7.1% of cases; 19% of patients underwent additional procedures. All patients had posterior mitral leaflet pathology and 19 patients had anterior mitral leaflet pathology. Ring annuloplasty was used in only 3% of cases. The operative mortality rate was 3.9%, 9% of patients had morbid events, and 4.5% of patients had repair failure within 6 months. All patients have been followed up with serial echocardiography for a mean time of 5.2 +/- 0.3 years (range 0.5 to 24 years). Immediately after operation, 92.9% had no mitral regurgitation to mild mitral regurgitation. At last follow-up, 96.9% had no mitral regurgitation to mild mitral regurgitation by echocardiography and 98% of patients were in New York Heart Association functional classes I and II. The actuarial survival at 15 years was 46% +/- 11%, freedom from reoperation was 84.9% +/- 11%, freedom from infective endocarditis was 96.0% +/- 11%, freedom from thromboembolism was 90.4% +/- 11%, and freedom from all valve-related events was 36.7% +/- 11%. It is well documented that repair of degenerative mitral valves offers excellent short-term and medium long-term benefits. This series represents the longest follow-up reported outside Europe. Our results beyond 10 years support our conclusion that an annuloplasty ring is not an absolute prerequisite for achieving successful repair of proven durability in most patients with degenerative mitral valve disease.
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Eleven patients (nine females, two males) with anaemia due to acute and chronic gastrointestinal blood loss were found to have gastric antral vascular ectasia (watermelon stomach). Nine patients were transfusion-dependent, receiving a mean of 13.1 units over a mean period of 12.3 months. All patients received neodymium:yttrium-aluminium-garnet laser coagulation with a median of 3.0 treatment sessions. Post-treatment transfusion needs were abolished in six patients and minimal in two patients during a mean follow up of 27.3 months (range 12-60 months). Overall there was a mean reduction in transfusion requirement with treatment from 2.5 units per month to 0.4 units per month (P < 0.02). Mean pretreatment haemoglobin improved from 7.7 to 11.9 g/dL after treatment (P < 0.001). No complications occurred. Laser coagulation is safe and effective treatment for anaemia due to watermelon stomach and should be considered as first line therapy.