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Biomedical subjects

S S Sandhu

Publications and source records attributed to S S Sandhu.

At least 19 recordsLinked to original sources
PubMed2006

Correlation of optical coherence tomography and fundus fluorescein angiography following photodynamic therapy for choroidal neovascular membranes.

AIMS: To assess the correlation between optical coherence tomography (OCT) and leakage on fundus fluorescein angiography (FFA) following photodynamic therapy (PDT) with verteporfin for choroidal neovascularisation (CNV). METHODS: Retrospective comparative observational case series of patients who were treated with PDT for CNV from one centre. All patients had 3 monthly FFA and OCT following initial PDT to assess if further treatment was required. A pair of FFA and OCT images from the same visit at a random follow up date were taken from each patient's series and assessed separately by different observers. The presence of pigment epithelial detachment, subretinal fluid, vitreomacular traction, intraretinal fluid, absence of foveal depression, and the retinal thickness on OCT were correlated with presence of leaks on FFA. RESULTS: A total of 121 eyes of 121 patients were included. The presence of subretinal fluid, gross cystoid macular oedema, sponge-like retinal thickening and retinal thickness of more than 350 mum on OCT correlated well with leak on FFA (p value <0.01). The likelihood ratios were 3.0, 5.7, 2.7, and 3.6, respectively. The presence of a solitary foveal cyst did not correlate well with leaks on FFA. CONCLUSIONS: The presence of subretinal fluid, intraretinal fluid in the form of gross cystoid macular oedema, or sponge-like retinal thickening, or a retinal thickness more than 350 mum correlates with leaks on FFA and so suggests the need for repeat PDT.

Adult↗
PubMed2005

Correlation of optical coherence tomography, with or without additional colour fundus photography, with stereo fundus fluorescein angiography in diagnosing choroidal neovascular membranes.

AIMS: To assess the diagnostic accuracy of optical coherence tomography (OCT), with/without colour fundus photographs, in predicting fundus fluorescein angiography (FFA) findings in patients suspected of having choroidal neovascularisation (CNV). METHODS: A consecutive series of patients suspected of having CNV underwent OCT and stereo FFA images, which were assigned a diagnosis by two masked observers, one examining OCT alone and then OCT plus stereo colour photographs, and one examining FFA alone. The main outcome measures were the diagnostic accuracy of OCT (with/without colour photos) in predicting the presence of CNV and secondly the characteristics of the CNV compared to the FFA findings. RESULTS: 131 eyes of 118 patients were analysed. The sensitivity and specificity of OCT for detecting new potentially treatable CNV lesions compared to FFA was 96.4%, and 66.0%, respectively. For OCT with stereo images the sensitivity was 94.0% and specificity 89.4%. For detecting CNV with a classic component the sensitivity and specificity of OCT alone was 78.6% and 82.7%. With stereo colour images the sensitivity was 82.1% and specificity 89.3%. CONCLUSION: OCT is good at detecting the presence of CNV in patients suspected of having new CNV. However, it is less accurate at identifying the exact components of CNV. OCT cannot at present replace FFA in accurately diagnosing CNV components. However, this imaging method may have a role as a screening tool to help prioritise FFA requests.

Adult↗
PubMed2002

RAPD analysis of herbicide-resistant Brasilian rice lines produced via mutagenesis.

Over the last two decades, mutational techniques have become one of the most important tools available to progressive rice- breeding programs. In a mutation-breeding program initiated in 1999 at the Instituto Agronômico of Campinas, SP, Brazil, a rice line, IAC103, was selected for mutational studies with gamma radiation and ethyl methyl sulfonate mutagenesis, with the aim of developing a herbicide-resistant crop. After mutagenesis, surviving plants were exposed to glufosinate to check for herbicide resistance, which was examined up to the second generation. A detailed RAPD analysis was made of the resistant plants. Eighty Operon technology primers were tested and 10 were selected for a detailed study of RAPD markers that could tag herbicide resistance genes. Resistant and susceptible lines produced variation in the RAPD patterns and certain bands were found only in certain lines. These results suggest genetic ligation that will be confirmed through a genetic segregation study.

Aminobutyrates↗
PubMed2001

Transformation system of Beauveria bassiana and Metarhizium anisopliae using nitrate reductase gene of Aspergillus nidulans.

An heterologous transformation system for entomopathogenic fungi B. bassiana and M. anisopliae was developed based on the use of A. nidulans nitrate reductase gene (niaD). B. bassiana and M. anisopliae niaD stable mutants were selected by treatment of protoplast with ethane methane sulphonate (EMS) and regenerated on chlorate medium. The cloned gene was capable of transforming B. bassiana and M. anisopliae at a frequency of 5.8 to 20 transformants per microg of DNA. Most of them were mitotically stable.

Aspergillus niger↗
PubMed1999

An improved cementing technique for revision hip surgery after peri-prosthetic fractures.

Replacement of the femoral component by a long-stemmed implant is one possible solution to the management of periprosthetic femoral shaft fractures. A problem often encountered, due to the extensive disruption of the femoral canal, is difficulty in achieving adequate cement pressurisation. We have overcome this by applying a split 60 ml syringe sleeve around the femoral shaft and holding it in position with clamps. This method has been used on five patients of mean age 87.7 (range 82-94) years with fractures that occurred at an average of 7.2 (range 4-17) years after the primary hip surgery. Two of the five patients achieved independent mobility and all of the patients were sufficiently independent to be discharged from the acute orthopaedic unit. We hope this cheap, effective method of supporting the bone fragments, maintaining alignment and achieving an acceptable level of pressurisation will lead to a decrease in the inevitable morbidity and mortality associated with a problem which as a result of an ageing population is likely to become increasingly common.

Aged↗
PubMed1997

Pure small cell carcinoma of the prostate.

Pure small cell carcinoma of the prostate is a rare anaplastic tumour. This report presents the clinicopathological findings of two patients presenting with this disease. Immunohistochemistry was positive for protein gene product 9.5, neurone specific enolase and calcitonin. Staining was negative for prostate specific antigen and prostate acid phosphatase. androgen ablation has no place in the management of this lesion and patients with this disease should be managed as if they have a neuroendocrine tumour.

Aged↗
PubMed1997

The impact of the accessibility of cranial CT scans on patient evaluation and management decisions.

OBJECTIVES: Cranial CT scans are amongst the most frequently performed radiological investigations performed in most developed countries. However, these tests are relatively expensive and economic realities should compel physicians to re-evaluate the utilization of this technology. The aim of this study was to review the utilization pattern and effect on management decisions of cranial CT scanning. DESIGN: Retrospective chart review. SETTING: University-affiliated community teaching hospital. SUBJECTS: The clinical data on 451 consecutive patients undergoing cranial CT scanning in our radiology department were reviewed. Eighty-five patients were referred from outside the hospital and were subsequently excluded from further analysis. INTERVENTIONS: None. MAIN OUTCOME MEASURES: The following data was abstracted from each patient's chart: the presenting clinical syndrome, the physician ordering the scan, details of the neurological examination performed prior to scanning, the CT scan findings and the impact the CT scan findings had on management decisions. RESULTS: The largest percentage of patients were referred from the emergency department (61%). Chronic intracranial lesions were present in 77 (21%) patients. New pathological findings were found in 91 (25%) patients. The commonest new lesions were ischaemic infarcts (43%), followed by intracerebral haemorrhage (13%) and space occupying lesions (11%). Ninety-seven per cent of patients presenting with new focal neurological signs had new findings on the CT scan, compared to 28% of patients with severe headache and 27% with a history of loss of consciousness. Head trauma was the presenting problem in 139 patients. New pathological findings were diagnosed in 24 of these patients. Fifty-four patients had no signs or symptoms referable to the central nervous system. None of these patients had new findings on CT scan. In the vast majority of patients the neurological examination performed prior to CT scanning was incomplete. CT scanning was considered to have altered the management or provided a new diagnosis in 162 (44%) patients; of these patients 61 (67%) were in the group with new findings on CT scanning and 101 (37%) in the group with no new findings. CONCLUSION: In this study cranial CT scanning affected clinical management decisions in less than half of the patients. Furthermore, a careful history and neurological examination was performed in the minority of patients undergoing CT scanning. It would therefore appear that the easy accessability of CT scans largely determines the utilization of this diagnostic tool.

Brain Diseases↗
PubMed1997

A prospective randomized study comparing a catheter-valve with a standard drainage system.

OBJECTIVE: To determine if the use of a catheter-valve rather than a standard drainage system decreases the morbidity associated with the use of a long-term catheter. PATIENTS AND METHODS: One hundred patients undergoing long-term catheterization were recruited into a prospective randomized study to investigate the acceptability and determine any increase in infection associated with the use of a catheter-valve, compared with the standard drainage system. Each patient participated in the study protocol for 3 months, during which the frequency of urinary tract infection was assessed, and the patients' views obtained using a standard questionnaire and by interview. RESULTS: Ninety-four patients completed the study; most (92%) were happy or satisfied with the valve, as opposed to only 35% of those using a standard drainage bag. There was no significant difference between the groups in the incidence of urinary tract infections. CONCLUSION: The patients who used the standard drainage system felt their level of activity was impaired, whereas the group who were using the valve did not. In the long-term the valve was cheaper and caused less morbidity, but because it is constructed to allow one-way flow, this was not associated with an increase in the incidence of urinary tract infections.

Adult↗
PubMed1997

Localised carcinoma of the prostate: a paradigm of uncertainty.

The incidence and prevalence of prostate cancer is increasing. A number of aetiological factors including age, race, family history and diet have been implicated. The majority of patients present with disease which is amenable only to palliation. Digital rectal examination, serum prostate-specific antigen and transrectal ultrasound can lead to a prostatic biopsy. Transrectal ultrasound, magnetic resonance imaging, bone scan and a chest X-ray are used for staging. The management of localised cancer is shrouded in uncertainty. Three options exist, watchful waiting, radiotherapy, and radical total prostatectomy. The published data are inadequate for a valid comparison of these, and none has been shown to offer an advantage. Surgery, and to a lesser degree radiotherapy, have a significant morbidity. It is hoped that through better understanding our management of this disease will improve.

Aged↗
PubMed1997

Who decides on the need for antibiotic prophylaxis in patients with major arthroplasties requiring dental treatment: is it a joint responsibility?

The role of antibiotic prophylaxis in patients with prosthetic joints who require dental treatment is controversial. A Working Party of the British Society for Antimicrobial Chemotherapy (BSAC) recently suggested that there was no evidence to support the use of antibiotic prophylaxis in these patients. The purpose of this study was to determine how closely these recommendations were being followed by maxillofacial surgeons (MFS), and to see if there was any consensus on the management of these patients between MFS and orthopaedic surgeons (OPS). With the aid of a postal questionnaire, the opinions of 250 consultant MFS and OPS were sought, response rates were 148 (59.2%) and 113 (41.2%), respectively. Of the OPS, 77.7% always recommended the use of antibiotic prophylaxis as opposed to only 29% of MFS. There were also wide differences in opinion with regard to the antibiotic that should be used in these patients, with the majority of OPS suggesting a cephalosporin, although this may not be the most efficacious antibiotic for oral streptococci. We conclude that this important matter seems to be far from satisfactorily resolved and that further cooperation between the specialties is required to produce guidelines for the safe and effective management of this increasing group of patients.

Antibiotic Prophylaxis↗
PubMed1997

Subpectoral breast reconstruction using the biodimensional system.

Increasing awareness among the general public has fuelled a demand for post-mastectomy breast reconstruction. However, owing to the limited number of plastic surgical centres this need is unlikely to be fulfilled in the near future. We report our early experience with a modified technique using a new subpectoral implant--the Biodimensional System. Seventeen consecutive patients underwent reconstruction (16 immediately) after mastectomy. In the group of patients having immediate reconstruction, the surgery was undertaken by the breast surgeon performing the primary procedure. This study demonstrates that an acceptable result can be obtained in the majority of patients and that it is possible for a breast surgeon to undertake primary reconstruction on selected patients using the Biodimensional System. It is hoped that this may aid patients in their physical and mental rehabilitation.

Breast Implants↗
PubMed1995

Liposome fusion and lipid exchange on ultraviolet irradiation of liposomes containing a photochromic phospholipid.

A photochromic phospholipid, 1,2-bis[4-4(4-n-butylphenylazo) phenylbutyroyl] phosphatidylcholine (Bis-Azo PC) has been incorporated into liposomes of gel- and liquid-crystalline- phase phospholipids. Liposomes of gel-phase phospholipid are stable in the presence of the trans photostationary state Bis-Azo PC and can encapsulate fluorescent marker dye. On photoisomerization to the cis photostationary state, trapped marker is rapidly released. Liposomes containing Bis-Azo PC can rapidly fuse together after UV isomerization, this process continuing in the dark. Exposure to white light causes reversion of Bis-Azo Pc to the trans form and halts dye leakage and vesicle fusion. Both unilamellar and multilamellar liposomes are able to fuse together on UV exposure. On UV photolysis, liposomes containing Bis-Azo PC do not fuse with a large excess of unlabeled liposomes, but transfer of Bis-Azo PC can be demonstrated spectrophotometrically. Vesicles of pure gel-phase lipid containing trapped marker dye but initially no Bis-Azo PC become leaky as a result of this lipid transfer. Liposomes composed of liquid-crystalline-phase phosphatidylcholine- containing Bis-Azo PC neither leak trapped marker no fuse together on photolysis, nor do liquid-crystalline-phase liposomes fuse with gel-phase liposomes under these conditions. These results are discussed together with some possible applications of liposome photodestabilization.

Fluorescent Dyes↗
PubMed1994

Environmental monitoring for genotoxicity with plant systems. An introduction and study design.

Under the sponsorship of the International Programme on Chemical Safety (IPCS), 17 laboratories from diverse regions of the world participated in evaluating the utility of four plant bioassays for detecting genetic hazards of environmental chemicals. The bioassays included in this collaborative study were: Arabidopsis thaliana embryo and chlorophyll assay and Tradescantia stamen hair assay, Tradescantia paludosa micronucleus assay and Vicia faba root tip assay. Four to six laboratories participated in the performance of each of the bioassays. All laboratories participating in a particular bioassay were supplied with uniform plant material as well as standardized protocol. Five direct acting water soluble test chemicals, i.e. maleic hydrazide, methyl nitrosourea, ethyl methanesulfonate, sodium azide and azidoglycerol, were selected for this study. The study was designed to be completed in three phases. Ethyl methanesulfonate was used as a positive control and has already been reported earlier (Sandhu et al., 1991). The data from the remaining four chemicals used for the evaluation of four plant test systems in the first phase of the collaborative study are reported in this issue.

Arabidopsis↗