Biomedical subjects
Publications and source records attributed to V Singh.
A short first total synthesis of phycopsisenone (1) utilizing microwave irradiation-induced aldol condensation and TiCl4-catalyzed reaction of silyl enol ether (3) with acetone as key steps has been achieved in 29.4% overall yield.
Fourteen minor (Na, K, P, Fe) and trace (Br, Co, Cr, Cs, Hg, Rb, Sb, Se, Sr, Zn) elements have been determined in pre- and postoperative blood samples of 10 breast-cancer-affected. Indian women and compared with controls. The study showed elevation of Cr, Hg, Fe, Rb, Sb, and Zn and lowering of Se, K, P, and Sr contents in the blood of cancer patients. Most elemental contents in pre- and postoperative stages remain unaltered except Br, Co, and Sb. Statistical significance of Fe, Se, Zn, and Hg levels has been tested by box plots. Lowering of Se in blood (-54.4%) is correlated with its enhancement in cancerous breast tissue (94.7%) of various clinical stages. Se/Zn and Se/Fe ratios are lowered in the blood of cancer patients, whereas Na/K ratio is only marginally enhanced. An attempt has been made to correlate Se levels with the dietary intake and breast cancer risk vis-a-vis American and Japanese women.
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The corrosion behaviour of an indigenous cast alloy of Ag-Sn-Cu, developed for crown and bridge prostheses, was studied in artificial saliva, with and without the addition of 0.1 M lactic acid, using a potentiostatic technique, and compared with that of the standard cast alloy of Ag-Pd (Ney 76). The values of different parameters such as corrosion potential and corrosion current density were determined for the indigenous alloy of Ag-Sn-Cu and the Ag-Pd alloy. The rate of corrosion of the indigenous alloy was found to be relatively higher than that of the Ag-Pd alloy up to an applied potential of + 400 mV. However, while the indigenous alloy showed a distinct tendency for passivation below + 200 mV at the current level of 0.5 mA/cm2 in the artificial saliva (pH 5.7) at 37 degrees C, no such tendency for passivation was shown by the Ag-Pd alloy even up to + 400 mV. The tendency for passivation by the indigenous Ag-Sn-Cu alloy, however, was not shown in the artificial saliva in the presence of 0.1 M lactic acid (pH. 2.7) at 37 degrees C. Minor variation was observed in the corrosion behaviour of the indigenous Ag-Sn-Cu alloys of different grades prepared by alloying elements of varying purity.
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Twenty preeclamptic, 25 normotensive pregnant and 25 healthy nonpregnant women were analyzed with regard to serum malonaldehyde (MDA), vitamin E and lipid profile. In preeclampsia, MDA was significantly higher than control. MDA also showed high correlation to the level of blood pressure. Serum cholesterol and triglycerides were increased in normotensive women and still higher in preeclamptic women. A highly significant fall in vitamin E levels in preeclamptic women was noted as compared to control groups. Our study supports the view that an increased lipid peroxidation may be involved in vasoconstriction in preeclampsia.
STUDY OBJECTIVES: Determination of the following: (1) colonization and infection rates in children requiring long-term ventilation initially via a transtracheal tube and subsequently via a tracheotomy; (2) the number of infection episodes per 1,000 ventilation days, during both types of artificial airways; and (3) routes of colonization/infection of the lower airways, ie, whether the pathogenesis was endogenous (via the oropharynx) or exogenous (via the transtracheal tube or tracheotomy). DESIGN: Observational, cohort, prospective study over 2 1/2 years. SETTING: Pediatric ICU (PICU), Royal Liverpool Children's National Health Service Trust of Alder Hey, a tertiary referral center. PATIENTS: Twenty-two children requiring long-term mechanical ventilation initially transtracheally and subsequently via a tracheotomy. INTERVENTION: Nil. RESULTS: The lower airways were colonized in 71% of children during transtracheal ventilation; posttracheotomy, this was 95% (p=0.03). Children developed significantly fewer infections following colonization with a microorganism posttracheotomy (8/15 pretracheotomy vs 6/21 posttracheotomy; p=0.013). Throughout the study, there were a total of 17 episodes of infection, all of which were preceded by colonization. Haemophilus influenzae, Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa were the same four causative pathogens during mechanical ventilation both transtracheally and via tracheotomy. Forty-nine episodes of colonization were observed, 15 pretracheotomy and 34 posttracheotomy; of these, 12 (80%) and 19 episodes (56%), respectively, were primary endogenous, ie, present in the oropharynx on hospital admission and subsequently at tracheotomy. Only one colonization episode (7%) of exogenous pathogenesis was observed during transtracheal intubation, while 12 (35%) (p=0.02) occurred after tracheotomy. An equal number of secondary endogenous colonization episodes (two and three, ie, acquired in the oropharynx after PICU admission and after tracheotomy, respectively, were recorded. CONCLUSIONS: (1) Despite a high level of hygiene, exogenous colonization without subsequent infection was common. (2) Although all patients were colonized, the infection rate was lower after tracheotomy. This may be due to enhanced immunity (medically stable) and improved tracheobronchial toilet. (3) Microorganisms in children with tracheotomy differ from those in adults.
A bacterial culture from telephone mouthpiece showed that 47 percent of the instruments carried pathogenic bacteria. Wiping with a disinfectant swab reduced the number of contaminated telephones. But for complete elimination of bacterial contamination changes in design of mouthpiece holes or type of instrument or using a polythene plastic cover over mouthpiece is recommended.
BACKGROUND: Acetylsalicyclic acid (ASA) causes gastric mucosal damage which diminishes with continued use due to adaptation. METHODS: To determine the net effect of these processes on the gastric juice, we estimated acid, osmolality, bicarbonate concentration in nonparietal gastric juice, calcium, potassium and sodium in 18 patients (9 men; mean age 32 years, range 20-46) with irritable bowel syndrome, before and after 600 mg of ASA taken post-cibum thrice daily for 4 weeks. Osmolality was determined by an osmometer, acidity by titration, and Na+, K+ and Ca++ using a sodium-potassium-calcium analyzer; bicarbonate was derived from the two-component model of Feldman. RESULTS: Gastric juice K+ and Na+ increased significantly from mean (SE) 14.6 (0.5) and 197.5 (16.3) to 16.7 (0.4) and 256.8 (18.1) mEq/L, respectively. The other parameters remained unchanged. CONCLUSION: After four weeks of ASA ingestion there is a dichotomy of gastric mucosal injury and adaptation, with preservation of acid secretion but continued loss of Na+ and K+.
A randomised prospective study to evaluate the role of adjuvant administration of pyridoxine hydrochloride was carried out in 104 patients undergoing radiation therapy. In study group 52 patients received tablet pyridoxine (controlled release) 100 mg daily one hour before the radiation therapy, for a period of 7 days, while the control group was treated by irradiation alone. Reduced radiation induced sickness was observed in study group (32.6% versus 48.1%). Loss of appetite (0% versus 1.9%), nausea (11.5% versus 21.1%) and vomiting (21.1% versus 28.8%) were lower for pyridoxine treated patients than for control patients. The above observed reduction in radiation induced sickness was found to be statistically insignificant (p > 0.05). The present data also did not reveal a statistical correlation between integral dose and radiation sickness.
Studies were conducted in order to assess the level of aluminium (Al) in samples of Indian tea, coffee, toothpaste, paan masala (mouth freshener) and baking powder. Leaching of Al from cookware while preparing tea and coffee was also studied. Experiments were also conducted to study the sequential leaching of Al from cookware by preparing tea and coffee in the presence of standard size Al sheets (coupons). A small amount of Al was found to have leached from coupons during preparation of tea. Tea leaves, were found to be a rich source of Al and a maximum of 2.2% Al is extracted in tea infusions. Coffee powder on the other hand was not found to be a rich source of Al. Baking powder was found to be a rich source of Al and 1 kg of cake prepared with 1-3 teaspoon of baking powder may contain 2-12.7 mg of Al in each serving (25 g). Toothpaste also contains a significant quantity of Al, more so, when packed in Al tubes. Ingestion pattern of Al from these items by humans is also discussed.
Population-based variations in frequency and distribution of dystrophin gene deletions have been recognized in Duchenne/Becker (DMD/BMD) muscular dystrophy patients. In the present study, DNA samples from 121 unrelated DMD/BMD patients from North India were analyzed for deletional studies with multiplex PCR and Southern hybridization. A total of 88 (73%) patients showed intragenic deletions in the dystrophin gene. The observed proportion of gene deletions is relatively high, particularly compared with that of Asian counterparts. However, the distribution of breakpoints across the gene does not show significant variations.
The electrocardiogram (ECG) of a 40-year-old woman with an old inferolateral myocardial infarction revealed, in the course of an exercise treadmill/thallium test, gradual disappearance of infarctional Q waves, which reappeared gradually during recovery from exercise. The patient had evidence of exercise-induced myocardial ischemia both by the ECG and by thallium-201 perfusion scintigraphy involving several myocardial regions. The temporal association of transient disappearance of Q waves with the occurrence of reversible ischemia suggested that the latter was instrumental in producing this phenomenon, through a transient failure of the ischemic anterior wall to shift the initial depolarization forces away from the infarcted inferolateral territory. Further evidence for this concept was provided by the case of another patient, a 49-year-old man who also had an old inferolateral myocardial infarction and whose ECG in the course of an exercise treadmill/thallium test did not reveal any changes in the infarctional Q waves. In this patient, thallium images showed mild, reversible inferolateral myocardial ischemia but a well perfused anterior wall, which provided for early depolarization forces (thus Q waves) directed opposite to the region of infarcted myocardium.
Specific parts of several plants (fruits, leaves, stem, bark, and roots) often used as medicines in the Indian Ayurvedic system have been analysed for 20 elements (As, Ba, Br, Ca, Cl, Co, Cr, Cu, Fe, K, Mn, Mo, Na, P, Rb, Sb, Sc, Se, Sr and Zn) by employing instrumental neutron activation analysis (INAA). The samples were irradiated with thermal neutrons in a nuclear reactor and the induced activity was counted using high resolution gamma ray spectrometry. Most of the medicinal herbs have been found to be rich in one or more of the elements under study.
Tracheoesophageal puncture is an established procedure for voice restoration following laryngectomy. A method using a flexible gastroscope and a percutaneous endoscopic gastrostomy (PEG) set is described. This overcomes a number of problems and complications which may be encountered when using a rigid endoscope.
Prior to flexible transnasal endoscopy (FTE) topical intranasal agents such as cocaine or combinations of a local anaesthetic and vasoconstrictor agent are generally recommended for local anaesthesia, easier access, and better examination of the interior of the nose, especially the middle meatus. This double-blind study involved 60 patients. Each had five per cent cocaine sprayed in one nostril and normal saline in the other. The pain/discomfort and gag scores showed no statistical difference. Forty-two (70 per cent) patients had a moderate/marked deviation of the nasal septum. A significant pain score (3-5) was obtained in 33.3 per cent of cases with the deviation towards the cocaine side and in 37 per cent of cases with the deviation towards the saline side. Ease of procedure scores for both sides were also comparable, when deviation of the nasal septum was taken into account.
Sinus histiocytosis with massive lymphadenopathy (SHML) is a rare, benign disease of unknown aetiology. This disease typically presents with massive, painless cervical lymphadenopathy but may occur in a wide variety of extranodal sites. Our report describes a 71-year-old man who presented with a discrete, unilateral parotid mass which was clinically suggestive of a primary salivary gland tumour. Initial cytological examination of a fine needle aspirate specimen taken from the mass demonstrated a discohesive cell population with nuclear atypia, raising the possibility of malignancy. However, excision of the mass and histological examination enabled a definitive diagnosis to be made.
In a hospital-based cytology screening programme for the early detection of preinvasive lesions of the uterine cervix, 166 women with abnormal smears (human papillomavirus (HPV) changes, cervical intraepithelial neoplasia (CIN) and invasive carcinoma) were referred to the central colposcopy clinic between January 1989 and December 1991. The colposcopist (V.S.) was able to take a direct biopsy in 156 cases. In the remaining 10-cases, biopsy could not be taken because of unsatisfactory colposcopy. A cytohistological correlation was obtained in 121/156 (77.5%) cases, and the remaining 35 cases showed a disparity in diagnosis. These were reviewed by one of us (P.S.) and the reasons for underdiagnosis/false negatives and overdiagnosis/false-positive results were analysed. It was found that sampling error was the cause of false negativity and underdiagnosis in most cases while interpretative errors resulted in the overdiagnosis and false-positive smears. The reasons for interpretative errors were studied in detail.