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M Patel

Publications and source records attributed to M Patel.

At least 55 records · Page 3Linked to original sources
PubMed2003

Periodontal pathogens in subgingival plaque of HIV-positive subjects with chronic periodontitis.

Many putative periodontal pathogens associated with periodontal disease in human immunodeficiency virus (HIV)-infected patients also occur in non-HIV-infected individuals. This study examined the prevalence of eight periodontal pathogens in HIV-positive and HIV-negative patients with chronic periodontitis using the 16s RNA polymerase chain reaction technique. The results showed a significant prevalence of Porphyromonas gingivalis and Treponema denticola among HIV-negative patients compared to HIV-positive patients. Sixty percent of the patients in both groups were colonized by five to six species. Odds ratio analysis revealed a statistically significant positive association between three of the 28 possible combinations in the HIV-positive group. They included Prevotella nigrescens/Campylobacter rectus, P. nigrescens/P. gingivalis and P. nigrescens/T. denticola. Although the prevalence of periodontal pathogens is similar in both the groups, the combination of certain periodontal pathogens may be responsible for chronic periodontitis seen in HIV-infected adults.

Adult↗
PubMed2003

Erosive pustular dermatosis of the leg associated with compression bandaging and fungal infection.

BACKGROUND: Erosive pustular dermatosis of the leg (EPDL) has been described in association with venous insufficiency and atrophy of the skin of the lower leg. Like erosive pustular dermatosis of the scalp, this disease has also been reported to be a non-infective condition. OBJECTIVES: To investigate the clinicopathological features and, where possible, the aetiology of clinical EPDL. METHODS: We identified a group of patients undergoing continuous compression bandaging for venous dermatitis of the legs and/or predominantly venous leg ulceration with clinical features described in patients with EPDL. They were investigated by skin biopsy, patch testing and microbiological tests for the presence of bacteria and fungi. RESULTS: Twenty-four of 400 (6%) patients were noted to have pustules on the leg(s). There was laboratory evidence of fungal infection in 13 of 24 patients (54%), with complete and sustained resolution of pustules after antifungal treatment. Pustulation in the other 11 patients (46%) was unresponsive to antibiotics for confirmed bacterial infection; some improvement was seen with potent topical corticosteroids but full clearance was achieved only after a switch from continuous four-layer compression bandaging to the use of intermittent long stretch compression. CONCLUSIONS: EPDL is a fairly common clinical picture seen in patients undergoing continuous compression bandaging. It may be produced by opportunistic, particularly fungal, infection. In almost half an infective aetiology cannot be demonstrated and a pyoderma gangrenosum-like process may be implicated.

Aged↗
PubMed2003

The imprinted region on human chromosome 7q32 extends to the carboxypeptidase A gene cluster: an imprinted candidate for Silver-Russell syndrome.

Imprinted gene(s) on human chromosome 7q32-qter have been postulated to be involved in intrauterine growth restriction associated with Silver-Russell syndrome (SRS) as 7-10% of patients have mUPD(7). Three imprinted genes, MEST, MESTIT1, and COPG2IT1 on chromosome 7q32, are unlikely to cause SRS since epigenetic and sequence mutation analyses have not shown any changes. One hundred kilobases proximal to MEST lies a group of four carboxypeptidase A (CPA) genes. Since most imprinted genes are found in clusters, this study focuses on analysing these CPAs for imprinting effects based on their proximity to an established imprinted domain. Firstly, a replication timing study across 7q32 showed that an extensive genomic region including the CPAs, MEST, MESTIT1, and COPG2IT1 replicates asynchronously. Subsequently, SNP analysis by sequencing RT-PCR products of CPA1, CPA2, CPA4, and CPA5 indicated preferential expression of CPA4. Pyrosequencing was used as a quantitative approach, which confirmed predominantly preferential expression of the maternal allele and biallelic expression in brain. CPA5 expression levels were too low to allow reliable evaluation of allelic expression, while CPA1 and CPA2 both showed biallelic expression. CPA4 was the only gene from this family in which an imprinting effect was shown despite the location of this family of genes next to an imprinted cluster. As CPA4 has a potential role in cell proliferation and differentiation, two preferentially expressed copies in mUPD patients with SRS syndrome would result in excess expression and could alter the growth profiles of these subjects and give rise to intrauterine growth restriction.

Alternative Splicing↗
PubMed2003

Iridium-192 implantation for T1 and T2a carcinoma of the tongue and floor of mouth: retrospective study of the results of treatment at the Royal Berkshire Hospital.

Carcinomas of the tongue and floor of mouth are relatively rare tumours, which may be treated using several modalities. We reviewed the results of iridium wire implants performed at the Royal Berkshire Hospital between 1994 and 2000. 24 patients had iridium wire implants as primary treatment for tongue and floor of mouth cancers. Four patients were treated after excision biopsy with close or involved margins. One patient was treated for a recurrence after surgery. The median age at treatment was 61 years. There were 18 men and 11 women. 21 patients had tumours of the tongue and eight of the floor of mouth. 13 had T1 tumours and 11 had T2a tumours. The median follow up was 42 months. The primary tumour was controlled in 22 of the 29 patients by the implant alone. Of the seven patients with local recurrence four were successfully salvaged with surgery. The acturarial 2 year survival rates were: overall survival 81%, disease specific survival 91%, local recurrence free survival 85% and nodal relapse free survival 76%. The recorded complication rate was low, one patient developing radionecrosis of the mandible at 7 years post implant. We believe these results show that brachytherapy remains a treatment option for patients with early tongue carcinoma with a high rate of local control and low toxicity.

Adult↗
PubMed2002

Risk factors for oesophageal, lung, oral and laryngeal cancers in black South Africans.

The authors used data collected from 1995 to 1999, from an on-going cancer case-control study in greater Johannesburg, to estimate the importance of tobacco and alcohol consumption and other suspected risk factors with respect to cancer of the oesophagus (267 men and 138 women), lung (105 men and 41 women), oral cavity (87 men and 37 women), and larynx (51 men). Cancers not associated with tobacco or alcohol consumption were used as controls (804 men and 1370 women). Tobacco smoking was found to be the major risk factor for all of these cancers with odds ratios ranging from 2.6 (95% CI 1.5-4.5) for oesophageal cancer in female ex-smokers to 50.9 (95% CI 12.6-204.6) for lung cancer in women, and 23.9 (95% CI 9.5-60.3) for lung cancer and 23.6 (95% CI 4.6-121.2) for laryngeal cancer in men who smoked 15 or more grams of tobacco a day. This is the first time an association between smoking and oral and laryngeal cancers has been shown in sub-Saharan Africa. Long-term residence in the Transkei region in the southeast of the country continues to be a risk factor for oesophageal cancer, especially in women (odds ratio=14.7, 95% CI 4.7-46.0), possibly due to nutritional factors. There was a slight increase in lung cancer (odds ratio=2.9, 95% CI 1.1-7.5) in men working in 'potentially noxious' industries. 'Frequent' alcohol consumption, on its own, caused a marginally elevated risk for oesophageal cancer (odds ratio=1.7, 95% CI 1.0-2.9, for women and odds ratio=1.8, 95% CI 1.2-2.8, for men). The risks for oesophageal cancer in relation to alcohol consumption increased significantly in male and female smokers (odds ratio=4.7, 95% CI=2.8-7.9 in males and odds ratio=4.8, 95% CI 3.2-6.1 in females). The above results are broadly in line with international findings.

Adolescent↗
PubMed2002

HLA class I and class II antigens associated with multiple myeloma in southern Africa.

While the exact aetiology of myeloma is unknown, genetic factors feature among the potential risk factors. The HLA phenotypes in African blacks with myeloma (the commonest haematopoietic malignancy in this group) have not been characterized. The purpose of this study was to determine the HLA class I and class II phenotypes of patients with multiple myeloma and to compare the findings to an ethnically matched control group of 100 individuals. Analysis of the HLA class I and class II phenotypes in 62 myeloma patients revealed: (i) a corresponding statistically significant association with HLA B18 [odds ratio (OR) 6.3; 95% confidence interval (CI) 1.013-39.727; P < 0.005]; (ii) no statistically significant association with HLA B13, Cw2, Cw6 or the DR and DQ antigens; and (iii) a statistically significant negative (protective) association with HLA Cw7 (OR 0.4; 95% CI 0.21-0.87; P < 0.005). This study suggests that although genetic factors may play a role in the multifactorial aetiology of multiple myeloma, with the exception of HLA B18, there is no specific association between HLA types and multiple myeloma in South African blacks.

Adult↗
PubMed2002

Clinical function after primary surgery for oral and oropharyngeal cancer: an 11-item examination.

The aim of this study was to record clinical function using an 11-item clinical examination and identify the main postoperative functional deficits. Of 132 consecutive patients undergoing surgery for previously untreated disease between January 1995 and June 1997, 130 were recruited in the study. An 11-domain clinical examination was made on the day before operation, and at 6 and 12 months afterwards. This examination assessed lip competence, tongue movement, oral mucosa, dental state, mouth opening, speech, drooling, diet, appearance, oral sensation and shoulder movement. Preoperatively there were deficits in natural dentition, consistency of diet and tongue protrusion. Postoperatively functional scores fell particularly for tongue movements, mouth opening, mucosa, dentition, speech, diet, appearance, lip sensation and tongue sensation. At 1 year, dental status, sensation and oral mucosa were particularly defective. Patients with large tumours, free tissue transfer, or adjuvant radiotherapy had the worst levels of function.A simple clinical examination provides a rapid assessment of function that can be used in conjunction with validated questionnaires to provide a more comprehensive evaluation of outcome.

Activities of Daily Living↗
PubMed2001

Effects of cations on ceramide-activated protein phosphatase 2A.

Characterization of ceramide-effector(s), which includes protein phosphatase 2A (PP2A) is an important prelude to understanding the molecular basis of sphingolipid-mediated biological effects such as cell growth, differentiation and apoptosis. Recently, the existence of a metal-dependent form of PP2A has been reported (Cai et al., 1995). In this study, we investigated the effects of metal ions and chelators on ceramide-activated PP2A (CAPP). Our study demonstrates that at 0.5 mM concentration, Mg2+ appears to have no significant effect on either basal or ceramide-stimulated phosphatase activities, whereas Ca2+ stimulated the basal phosphatase activity, but was inhibitory towards CAPP. Moreover, the divalent cations Cr2+, Mn2+, Fe2+, Ni2+, Cu2+ and Zn2+ were tested and all were found to be inhibitory towards both CAPP and basal phosphatase activities. By contrast, Cs+ and Li+ had almost no effect on CAPP, although both stimulated basal phosphatase activity. The effects of EDTA and EGTA were tested and it was observed that EDTA decreased CAPP activity in a dose-dependent fashion, but had no effect upon basal phosphatase activity. These results suggest that CAPP is a metal-dependent protein, but, because Ca2+ inhibitied CAPP and EGTA was much less potent than EDTA in inhibiting CAPP, Ca2+ is unlikely to be its metal cofactor.

Cations, Divalent↗
PubMed2001

The sodium channel beta-subunit SCN3b modulates the kinetics of SCN5a and is expressed heterogeneously in sheep heart.

1. Cardiac sodium channels are composed of a pore-forming alpha-subunit, SCN5a, and one or more auxiliary beta-subunits. The aim of this study was to investigate the role of the recently discovered member of the beta-subunit family, SCN3b, in the heart. 2. Northern blot and Western blot studies show that SCN3b is highly expressed in the ventricles and Purkinje fibres but not in atrial tissue. This is in contrast to the uniform expression of SCN1b throughout the heart. 3. Co-expression of SCN3b with the cardiac-specific alpha-subunit SCN5a in Xenopus oocytes resulted in a threefold increase in the level of functional sodium channel expression, similar to that observed when SCN1b was co-expressed with SCN5a. These results suggest that both SCN1b and SCN3b improve the efficiency with which the mature channel is targeted to the plasma membrane. 4. When measured in cell-attached oocyte macropatches, SCN3b caused a significant depolarising shift in the half-voltage of steady-state inactivation compared to SCN5a alone or SCN5a + SCN1b. The half-voltage of steady-state activation was not significantly different between SCN5a alone and SCN5a + SCN3b or SCN5a + SCN1b. 5. The rates of inactivation for SCN5a co-expressed with either subunit were not significantly different from that for SCN5a alone. However, recovery from inactivation at -90 mV was significantly faster for SCN5a + SCN1b compared to SCN5a + SCN3b, and both were significantly faster than SCN5a alone. 6. Thus, SCN1b and SCN3b have distinctive effects on the kinetics of activation and inactivation, which, in combination with the different patterns of expression of SCN3b and SCN1b, could have important consequences for the integrated electrical activity of the intact heart.

Animals↗
PubMed2001

Dual functions for connexins: Cx43 regulates growth independently of gap junction formation.

Connexins, the family of proteins that form vertebrate gap junctions, have key roles during development and in the adult. Previously, the physiological actions of connexins have been ascribed solely to formation of gap junction channels and thought to be mediated by the transfer of small molecules between neighboring cells. In conflict with this hypothesis here we demonstrate that Cx43 can affect cell growth independently of gap junction formation. This conclusion is based on four findings: (1) There is a lack of correlation between the action of Cx43 mutants Cx43-S255A, Cx43-S279A, and Cx43-S282A on growth and cell coupling in 3T3 A31 fibroblasts. (2) Blockade of gap junction formation, by either heptan-1-ol treatment or culturing cells at low density, had no effect on the ability of the Cx43 mutants to control growth. (3) Wildtype Cx43 inhibited growth of Neuro2a cells under conditions where gap junctions were unable to form. (4) The CT domain of Cx43, which lacks intrinsic gap junction activity, is as effective as the wildtype molecule in suppressing the growth of Neuro2a cells. These observations demonstrate that Cx43 has dual functions: first, its well-accepted role in forming a gap junction channel and, second, a direct action of the connexin protein on growth that is mediated via the cytoplasmic carboxyl domain.

3T3 Cells↗
PubMed2001

Lifespan extension and rescue of spongiform encephalopathy in superoxide dismutase 2 nullizygous mice treated with superoxide dismutase-catalase mimetics.

Superoxide is produced as a result of normal energy metabolism within the mitochondria and is scavenged by the mitochondrial form of superoxide dismutase (sod2). Mice with inactivated SOD2 (sod2 nullizygous mice) die prematurely, exhibiting several metabolic and mitochondrial defects and severe tissue pathologies, including a lethal spongiform neurodegenerative disorder (Li et al., 1995; Melov et al., 1998, 1999). We show that treatment of sod2 nullizygous mice with synthetic superoxide dismutase (SOD)-catalase mimetics extends their lifespan by threefold, rescues the spongiform encephalopathy, and attenuates mitochondrial defects. This class of antioxidant compounds has been shown previously to extend lifespan in the nematode Caenorhabditis elegans (Melov et al., 2000). These new findings in mice suggest novel therapeutic approaches to neurodegenerative diseases associated with oxidative stress such as Friedreich ataxia, spongiform encephalopathies, and Alzheimer's and Parkinson's diseases, in which chronic oxidative damage to the brain has been implicated.

Animals↗
PubMed2001

Interactions among ascorbate, dehydroascorbate and glucose transport in cultured hippocampal neurons and glia.

There is an increasing recognition of the damaging role played by oxygen radicals in mediating necrotic neuronal injury. As such, it becomes important to understand the transport mechanisms that help maintain appropriate levels of small molecule antioxidants such as ascorbate in the brain. It has long been known that the transport of dehydroascorbate (DHA) into a variety of cell types is accomplished through the Glut-1 glucose transporter. In this paper, we characterize interactions among the transports of ascorbate, DHA and glucose in hippocampal cultures. We find: (a) sodium-dependent transport of ascorbate in mixed neuronal/glial, pure glial, and neuron-enriched hippocampal cultures; in contrast, we observed no such transport of DHA; (b) such ascorbate transport appeared to be independent of the glucose transporter, in that glucose did not compete for such transport, and overexpression of the Glut-1 glucose transporter did not alter ascorbate uptake; (c) in contrast, ascorbate, at concentrations ranging from 1 to 20 mM inhibited 2-dexogyglucose transport in mixed, glial and enriched neuronal hippocampal cultures; (d) potentially, ascorbate, by acting as an electron donor, could impair the function of molecules involve in the transport or metabolism of glucose. We observed mild inhibition of glucose transport by one unrelated electron donor (glutathione). Moreover, transport was also inhibited by an ascorbate analog which is not an electron donor. Thus, we conclude that ascorbate transport in hippocampal neurons and glia occurs independent of the glucose transporter but that, nevertheless, ascorbate, at concentrations generally thought to be supraphysiological, has the potential for disrupting glucose transport.

Animals↗
PubMed2001

Hydrophobicity, a physicochemical factor in the inhibition of the enzyme estrone sulfatase (ES).

We report the initial structure-activity relationship study (SAR) (in particular logP) of a series of compounds based upon 4-sulfamated phenyl ketones as potent inhibitors of the enzyme estrone sulfatase (ES). The results of the study show that these compounds are irreversible inhibitors of ES and that they are more potent than COUMATE, but weaker than EMATE. Analysis of the SAR data shows a strong correlation between IC(50) and logP but also supports our previous study, which suggests a very strong relationship between pK(a) and IC(50).

Chemistry, Physical↗
PubMed2001

The inter- and intraobserver reliabilities of a new classification system for ischaemic stroke: the South London Stroke Register.

OBJECTIVES: This study aims to determine the inter- and intraobserver reliabilities of an aetiological classification devised as part of a community-based stroke register. METHODS: Patients with first-ever acute ischaemic stroke were clinically assessed and received investigation according to a set protocol. Results of the clinical assessment and investigations were used to determine an aetiological stroke subtype for each patient by observer 1. Aetiological subtypes consisted of extracranial large artery atherosclerosis (LAAec), intracranial large artery atherosclerosis (LAAic), high-risk cardioembolism (CH), medium-risk cardioembolism (CM), small vessel occlusion (SVO), other aetiology (OTH), no aetiology identified (NA) and multiple probable or multiple possible aetiology (MPA). The same data were distributed to a further four observers along with the criteria for the classification system. Two of the observers were retested on the same patients after of period of 8 weeks. Inter- and intraobserver agreement was determined using the kappa statistic, which gives the chance-adjusted percentage agreement. RESULTS: Forty-five consecutive patients were included. The overall kappa statistic for ischaemic stroke was 0.91 indicating excellent agreement. Kappa statistics were highest for the more frequent subtypes of SVO (0.97) and CH (0.97). Substantially high kappa statistics were also obtained for the less-frequent categories of LAAec (0.91), CM (0.84), NA (0.89) and MPA (0.87). A low kappa statistic was obtained for the category OTH (0.16), which had a low frequency of reporting, indicating poor agreement. The kappa statistic for probable categories was higher than the kappa statistic for all stroke subtypes at 0.96. Intraobserver agreement between first and second assignments of subtype diagnoses for both observers reached excellent agreement with kappa statistics of 0.83 and 0.85. CONCLUSION: The aetiological classification system, designed for use in the investigation of the epidemiology, stroke subtype and their relation to the natural history of stroke in a multiethnic inner city population, allows high inter- and intrarater agreements of subtype diagnosis.

Acute Disease↗
PubMed2001

Capacity of Irpex lacteus and Pleurotus ostreatus for decolorization of chemically different dyes.

The rate and efficiency of decolorization of poly R-478- or Remazol Brilliant Blue R (RBBR)-containing agar plates (200 microg x g(-1)) were tested to evaluate the dye degradation activity in a total of 103 wood-rotting fungal strains. Best strains were able to completely decolorize plates within 10 days at 28 degrees C. Irpex lacteus and Pleurotus ostreatus were selected and used for degradation of six different groups of dyes (azo, diazo, anthraquinone-based, heterocyclic, triphenylmethane, phthalocyanine) on agar plates. Both fungi efficiently degraded dyes from all groups. Removal of RBBR, Bromophenol blue, Cu-phthalocyanine, Methyl red and Congo red was studied with I. lacteus also in liquid medium. Within 14 days, the following color reductions were attained: RBBR 93%, Bromophenol blue 100%, Cu-phthalocyanine 98%, Methyl red 56%, Congo red 58%. The ability of I. lacteus to degrade RBBR spiked into sterile soil was checked, the removal being 77% of the dye added within 6 weeks. The capacity of selected white rot fungal species to remove efficiently diverse synthetic dyes from water and soil environments is documented.

Agaricales↗