Biomedical subjects
Publications and source records attributed to B Singh.
Tuberculosis isolated to the spleen is a rare clinical entity particularly in the non-HIV-positive patient population. In the four patients described, two presented with thrombocytopenia; in two patients the condition was diagnosed serendipitously at laparotomy undertaken for abdominal trauma.
Cystic changes can arise in relation with unerupted lower third molars. This case report describes a large odontogenic keratocyst (OKC) which developed rapidly and aggressively over a short period of 2 years and presented with acute symptoms. The development of a large OKC over the mandible is evidenced by radiographs taken 2 years apart. The OKC was enucleated and the residual cavity was treated with Carnoy's solution and packed with bismuth iodoform paraffin paste dressing. The impacted third molar and second molar associated with the lesion were also extracted. This case illustrates how rapidly a cyst can develop in association with a previously asymptomatic, unerupted tooth and how quickly a radiographic diagnosis can become out of date. As such, the authors recommend the use of repeated radiographs for monitoring unerupted teeth at a tighter time frame of 6 to 12 months.
Drug eluting stents have made a significant impact on restenosis. However, there are concerns regarding delayed "catch-up" of restenosis. In this case report we present two such patients with delayed occurrence of restenosis after drug eluting stent implantation.
In this study, we analysed gene amplification, RNA expression and protein expression of the c-myc gene on archival tissue specimens of high-grade human breast cancer, using fluorescent in situ hybridisation (FISH), nonradioactive in situ hybridisation and immunohistochemistry. The specific question that we addressed was whether expression of c-Myc mRNA and protein were correlated with its gene copy amplification, as determined by FISH. Although c-Myc is one of the most commonly amplified oncogenes in human breast cancer, few studies have utilised in situ approaches to directly analyse the gene copy amplification, RNA transcription and protein expression on human breast tumour tissue sections. We now report that by using the sensitive FISH technique, a high proportion (70%) of high-grade breast carcinoma were amplified for the c-myc gene, irrespective of status of the oestrogen receptor. However, the level of amplification was low, ranging between one and four copies of gene gains, and the majority (84%) of the cases with this gene amplification gained only one to two copies. Approximately 92% of the cases were positive for c-myc RNA transcription, and essentially all demonstrated c-myc protein expression. In fact, a wide range of expression levels were detected. Statistically significant correlations were identified among the gene amplification indices, the RNA expression scores and protein expression scores. c-myc gene amplification, as detected by FISH, was significantly associated with expression of its mRNA, as measured by the intensity of in situ hybridisation in invasive cells (P=0.0067), and by the percentage of invasive cells positive for mRNA expression (P=0.0006). c-myc gene amplification was also correlated with the percentage of tumour cells which expressed high levels of its protein, as detected by immunohistochemistry in invasive cells (P=0.0016). Thus, although multiple mechanisms are known to regulate normal and aberrent expression of c-myc, in this study, where in situ methodologies were used to evaluate high-grade human breast cancers, gene amplification of c-myc appears to play a key role in regulating expression of its mRNA and protein.
Stellate ganglion blockade (SGB) has long been considered pivotal in the diagnosis, determination of prognosis and management of chronic regional pain syndrome (CRPS) by sympathectomy. To date a variety of SGB techniques have been described. An inaccurate SGB may mislead clinicians and deny patients a potentially beneficial procedure. In order to obtain a predictable and readily reproducible blockade of the upper limb, a modified anterior technique was evaluated. This modified sympathetic block was performed in 10 adult cadavers (n=19 sides). Toluidine blue solution (10 ml) was injected and, following median sternotomy, the extent of spread of dye was evaluated. In one cadaver a dual block using both the modified and the standard techniques was performed. Proximal spread to the seventh cervical vertebra was noted in all blocks; distal spread extended to the neck of the third rib (n=3), neck of the fourth rib 7 (n=15) and neck of the seventh rib (n=1). Medial spread was greater than lateral spread and extended to the vertebral bodies (vagus nerve was also stained) while lateral spread in all cases "blocked" lower roots of the brachial plexus and was consistently noted beyond the usual location of the nerve of Kuntz. This modified technique demonstrated that the lower cervical ganglia and proximal thoracic sympathetic trunk were consistently stained. It should be noted that the spread was sufficiently lateral to block the nerve of Kuntz. The pitfalls of this technique aside, we suggest that this technique be reserved for therapeutic purposes, particularly when sympathectomy is not possible.
BACKGROUND: The management of perianal Crohn's disease is difficult. A wide variety of treatment options exist although few are evidence based. METHODS: A search was conducted using the National Library of Medicine for articles on perianal Crohn's disease and its incidence, classification, assessment and management. RESULTS AND CONCLUSION: Perianal Crohn's disease can manifest as skin tags, ulcers, fissures, abscesses, fistulas or stenoses. Improved radiological imaging with endoanal anal ultrasonography and magnetic resonance imaging has improved its assessment and may be used to predict outcome after surgery. Many treatment options exist. During acute complications they are generally aimed at resolving the immediate problem and limiting damage to anal and perianal tissues; this may be a 'bridge' to definitive treatment. The likelihood of success of definitive treatment must be weighed against the risk of complications, especially faecal incontinence.
In this clinico-anatomical study, factors potentially responsible for unsuccessful upper limb sympathectomy (ULS) by the thoracoscopic route were evaluated. This study comprised two subsets: 1) in the clinical subset, 25 patients (n = 50 sides) underwent bilateral second thoracic ganglionectomy for palmar hyperhidrosis, and factors predisposing to unsuccessful ULS were identified; and 2) in the anatomical subset, the neural connections of the first and second intercostal spaces were bilaterally dissected in 22 adult cadavers (22 right, 21 left; n = 43 sides). Alternate neural pathways (ANP) were noted in 9 of 50 sides in the 25 clinical cases (18%). In three asthenic patients (5 sides), fascia overlying the longus colli muscle mimicked the sympathetic chain. The right superior intercostal vein (SIV) was located anterior to the second thoracic ganglion in 6 of 50 sides (12%) and predisposed to troublesome bleeding in 2 of 50 cases; the SIV was posterior to the ganglion in 19 of 50 sides (38%), posing no technical problem. On the left, the SIV was noted outside the field of dissection in all but one case. A successful outcome to sympathectomy was noted in all 25 patients. A spectrum of sympathetic contributions to the first thoracic ventral ramus for the first intercostal space was noted in 37 of 43 anatomical cases (86%). These were categorized according to the arrangements of the intrathoracic ramus between the second intercostal nerve and the first thoracic ventral ramus. The cervicothoracic ganglion (37/43 cases; 86%) and an independent inferior cervical ganglion (6/43 cases; 14%) were always located above the second rib. The second thoracic ganglion was consistently located in the second intercostal space. This study demonstrates that ANPs have little clinical significance when a second thoracic ganglionectomy is undertaken. Technical failures may be avoided if the surgeon is mindful of anatomical variations at surgery.
The hexane extract of Arnebia hispidissima yielded a mixture of naphthaquinones: arnebin-1, arnebin-7, tiglic acid (ester of dihydroxy alkannin), alkannin, arnebinol and cycloarnebin-7. To evaluate the anti-inflammatory activities of hexane extract and isolated naphthaquinones, models with carrageenan-induced acute arthritis and complete Freund's adjuvant (CFA)-induced chronic arthritis in rats were conducted. The observed results indicated that pretreatment with cycloarnebin-7 significantly inhibited the carrageenan-induced acute arthritis. Moreover, arnebin-1, significantly suppressed the development of chronic arthritis induced by CFA. The present study deals with the quantification of naphthaquinones from in vivo and in vitro cell cultures of plant species and isolated compounds from intact plant tested for their swelling inhibitory potency. It has been reported that arnebin-1 was the major naphthaquinone both in vivo (0.62%) and in vitro (0.27%) cell cultures.
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Histopathological studies of the cutaneous tissues of Wistar rats exposed to UV B radiation (294 nm) for 20 days and rats exposed to UV B radiation for 20 days, followed by topical treatment with benzoyl peroxide, a tumor promoter (20 mg/animal/0.2 ml acetone) twice a week for 1 month, and kept under observation for 12 weeks, demonstrate the development of malignancy. Pretreatment of the animals with 1-oxo-5beta, 6beta-epoxy-witha-2-enolide (20 mg/kg bwt.), isolated from the roots of Withania somnifera, prior to exposing the animals to UV B radiation, prevents the incidence of skin carcinoma. The administration of 1-oxo-5beta, 6beta-epoxy-witha-2-enolide, to the animals after exposing them to UV B radiation/UV B radiation and benzoyl peroxide also prevents the occurrence of malignancy in the cutaneous tissue. Immunohistochemical staining of the cutaneous tissues of rats exposed to UV B radiation show the presence of p53 + foci (clusters of cells containing the mutated p53 protein), whereas an absence of p53 + foci is observed in animals pretreated with 1-oxo-5beta, 6beta-epoxy-witha-2-enolide. These results prove that 1-oxo-5beta, 6beta-epoxy-witha-2-enolide has the potential for acting as an effective agent to prevent the incidence of skin carcinoma induced by UV B radiation.
Achieving optimal cyclosporine (Neoral) absorption is critical for successful graft outcome. Recently there have been studies on postdose monitoring of cyclosporine. Two- and 3-hour postdose cyclosporine levels measured by radioimmunoassay were correlated with occurrence of rejection and cyclosporine nephrotoxicity in 30 patients; C(2) and C(3) levels were significantly lower than the desired therapeutic levels in patients with acute rejection. Based on our study and those of others we suggest C(3) levels should be adopted in clinical practice.
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The alkaline single cell gel electrophoresis assay was performed on peripheral blood lymphocytes of lepromatous and tubercloid leprosy patients (untreated and those undergoing treatment) in order to ascertain whether differential damage to DNA occurs. The study group included 28 male and 2 female patients and 15 healthy males who were matched for age and socio-economic status. The results revealed DNA damage in all patients, with a mean DNA migration length of 29.88 +/- 3.39 microm and 38% of their cells damaged when compared with the respective values obtained in healthy controls (1.28 +/- 0.40 microm, 5%). Multiple regression analysis for effects of confounding factors revealed antibiotic treatment in patients and alcohol consumption in controls as the only variables influencing DNA damage. In lepromatous and tubercloid patients, both untreated and those undergoing treatment, DNA damage increased significantly from that observed in control individuals, with greater increased damage in lepromatous patients. An increase in treatment time increased DNA damage linearly. Furthermore, an arbitrary classification of damaged cells (categories I-IV) was made based on observed tail lengths in leprosy patients (5.00-225.00 microm). The number of damaged cells in untreated patients was lower than in those undergoing treatment; the latter also had more cells with greater DNA migration lengths. There were no category III or IV cells in the control group. The results of the study therefore reveal that patients undergoing therapy had significantly greater DNA damage than untreated patients, indicating bacterial infection and drug therapy as the causal factors, since lepromatous-type disease is the more severe form with the patients having lower resistance to Mycobacterium leprae and requiring heavier and prolonged dosage of antibiotics. The study also corroborates that the assay offers an opportunity for correlating levels of therapy-induced DNA damage with administered dose and for modulating the dose-schedule so as to achieve lower levels of genotoxic damage.
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