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Biomedical subjects

P Rai

Publications and source records attributed to P Rai.

At least 19 recordsLinked to original sources
PubMed2005

Biological aspects of tooth fragment reattachment in immature incisors.

Tooth fragment reattachment is a relatively new technique and there are many aspects which still need to be explored. Reported here is a case of enamel and dentin fracture of 11 and 21. There was a very thin layer of dentin clinically over the pulp chamber and the root apices were immature. The reattachment procedure was modified slightly. The initial joint was made with protective calcium hydroxide and glass ionomer cement on the approximating surfaces. The further reattachment was accomplished using composites and acid etch technique. This was done for pulpal protection. After six months, reattachment was intact and successful with no staining, sensitivity or pain. The radiographs revealed root completion of the immature incisors. The reattachment procedure proved to be biologically superior in addition to its esthetic value and psychological advantage.

Accidental Falls↗
PubMed2005

Fly-ash induced synthesis of phytochelatins in chickpea (Cicer arietinum L.) plants.

Phytochelatins and related metabolites (cysteine and GSH) were found to be induced in the shoots of two varieties of Cicer arietinum viz., CSG-8962 and C-235 grown under different amendments of fly-ash with garden soil and press mud. Cysteine, GSH, PCs and its speciation were found in higher concentrations in amended fly-ash than in the control 100% soil. Two species of metal binding peptides i.e., PC2 and PC4 were found in both varieties and in amendments, however, their concentration varied depending upon the fly-ash concentrations in both amendments. Further, var. CSG-8962 was found more tolerant than var. C-235 because of higher concentrations of PCs and related metabolites.

Carbon↗
PubMed2001

Localization of Fe(2+) at an RTGR sequence within a DNA duplex explains preferential cleavage by Fe(2+) and H2O2.

Nicking of duplex DNA by the iron-mediated Fenton reaction occurs preferentially at a limited number of sequences. Of these, purine-T-G-purine (RTGR) is of particular interest because it is a required element in the upstream regulatory regions of many genes involved in iron and oxidative-stress responses. In order to study the basis of this preferential nicking, NMR studies were undertaken on the RTGR-containing duplex oligonucleotide, d(CGCGATATGACACTAG)/d(CTAGTGTCATATCGCG). One-dimensional and two-dimensional 1H NMR measurements show that Fe(2+) interacts preferentially and reversibly at the ATGA site within the duplex at a rate that is rapid relative to the chemical-shift timescale, while selective paramagnetic NMR line-broadening of the ATGA guanine H8 suggests that Fe(2+) interacts with the guanine N7 moiety. Localization at this site is supported by Fe(2+) titrations of a duplex containing a 7-deazaguanine substitution in place of the guanine in the ATGA sequence. The addition of a 100-fold excess of Mg(2+) over Fe(2+) does not affect the Fe(2+)-dependent broadening. When the ATGA site in the duplex is replaced by ATGT, an RTGR site (GTGA) is created on the opposite strand. Preferential iron localization then takes place at the 3' guanine in GTGA but no longer at the guanine in ATGT, consistent with the lack of preferential cleavage of ATGT sites relative to ATGA sites.

Base Pairing↗
PubMed2001

Orbital myiasis: a case report.

Myiasis; a term first introduced by HOPE refers to invasion of living tissue of humans and other mammals by the eggs or larvae of flies of the order of Diptera. Orbital involvement occurs in approximately 5% of all cases of myiasis. A 72 year old patient is presented with orbital myiasis that was successfully treated by enucleation and grafted with split thickness of skin.

Aged↗
PubMed2000

In-situ irradiation of keloid scars with Nd:YAG laser.

In-situ coagulation of keloid with Nd:YAG laser irradiation was carried out in in a cohort study of 17 patients, each with one keloid scar situated on either the sternum (six), abdomen (seven), shoulder (two), hip (one), or ear lobe (one). The duration of scarring was three to 17 years and size varied from 3-8 cm long. One to two doses of laser irradiation was required for complete coagulation. At three months, 10 (58.8%) keloids had completely healed; but in seven (41.1%), 25-50% of residual keloid persisted. Intralesional triamcinolone injection, once in four patients and twice in three patients, produced complete resolution in all seven patients. At 18 months to five years follow-up, 14 patients remain keloid-free but in three keloid recurred and was re-treated with laser coagulation with complete resolution. The treatment was carried out as an outpatient procedure under local anaesthesia. There were no complications. The results of this initial study suggest that Nd:YAG laser irradiation coagulation is effective treatment for keloid scarring.

Adolescent↗
PubMed1999

Sequence-specific DNA cleavage by Fe2+-mediated fenton reactions has possible biological implications.

Preferential cleavage sites have been determined for Fe2+/H2O2-mediated oxidations of DNA. In 50 mM H2O2, preferential cleavages occurred at the nucleoside 5' to each of the dG moieties in the sequence RGGG, a sequence found in a majority of telomere repeats. Within a plasmid containing a (TTAGGG)81 human telomere insert, 7-fold more strand breakage occurred in the restriction fragment with the insert than in a similar-sized control fragment. This result implies that telomeric DNA could protect coding DNA from oxidative damage and might also link oxidative damage and iron load to telomere shortening and aging. In micromolar H2O2, preferential cleavage occurred at the thymidine within the sequence RTGR, a sequence frequently found to be required in promoters for normal responses of many procaryotic and eucaryotic genes to iron or oxygen stress. Computer modeling of the interaction of Fe2+ with RTGR in B-DNA suggests that due to steric hindrance with the thymine methyl, Fe2+ associates in a specific manner with the thymine flipped out from the base stack so as to allow an octahedrally-oriented coordination of the Fe2+ with the three purine N7 residues. Fe2+-dependent changes in NMR spectra of duplex oligonucleotides containing ATGA versus those containing AUGA or A5mCGA were consistent with this model.

Base Sequence↗
PubMed1995

The AMPA antagonist NBQX provides partial protection of rat cerebellar Purkinje cells after cardiac arrest and resuscitation.

Purkinje cell loss in adult rats resuscitated following cardiac arrest is analogous to that seen following human cardiac arrest. Administration of the competitive AMPA antagonist NBQX to rats resuscitated after 10 min duration cardiac arrest rescued 21.5% of the vulnerable Purkinje cell population. These results support the hypothesis that sustained postischemic overexcitation of AMPA receptors may be a driving force in the process of Purkinje cell degeneration.

Animals↗
PubMed1995

Luminal bacterial overgrowth and intestinal translocation in pigs given either cyclosporin A or 15-deoxyspergualin after small bowel transplantation.

OBJECTIVE: To examine the effects of two immunosuppressant regimens on composition of the bowel flora and rate of translocation after transplantation of the small bowel in pigs. DESIGN: Randomised controlled study. SETTING: University hospital, Italy. MATERIAL: 35 female Large White pigs. INTERVENTIONS: 9 Animals were not operated on (normal controls). 19 Animals underwent total orthotopic small bowel allotransplantation and were then randomised to receive: group A (n = 8) cyclosporin A 25 mg/kg subcutaneously and cephazolin 2 g intramuscularly daily; group B (n = 6) 15-deoxyspergualin (15-dos) 3 mg/kg for 7 days then 1.5 mg/kg, cephazolin 2 g intramuscularly daily for 4 days then selective intestinal decontamination with colistin 1.5 million U, tobramycin 100 mg, vancomycin 1 g, and nystatin 500,000 U daily; and group C (n = 5) cephazolin 2 g intramuscularly daily for 8 days. A further group (D, n = 7) underwent orthotopic autotransplantation and received the same antibiotic and selective decontamination regimens as group B. Animals in group C were killed on day 8, and the rest on day 29. MAIN OUTCOME MEASURES: Signs of rejection, graft versus host disease, luminal overgrowth, and evidence of translocation to mesenteric lymph nodes. RESULTS: All animals in group C, and 2 in group B, showed signs of acute rejection. There was a significant overgrowth of both aerobic and anaerobic bacteria in all 3 groups after allotransplantation compared with normal controls. Bacterial translocation was similar in autografted and allotransplanted animals. Mesenteric lymph nodes were colonised in 4/9 controls, 7/8 in group A, 4/4 in group B, 5/5 in group C, and 7/7 in group D. CONCLUSION: Neither cyclosporin A nor 15-dos prevented luminal overgrowth or bacterial translocation to mesenteric nodes up to one month after operation. The rate of translocation was similar in autotransplantation and allotransplantation, suggesting that non-immunological factors (for example, denervation and interruption of lymphatics) may have a role in these alterations.

Animals↗
PubMed1994

Community financing of drug supplies in rural Nepal: evaluating a 'fee per item' drug scheme.

A new programme in rural Nepal was evaluated in which users partly fund the supply of additional drugs needed at health posts. Patients are charged a fee per item prescribed (FPI scheme). The scheme is administered by the District Public Health Office (DPHO). This scheme is compared with two established schemes: one charges patients a fee per prescription ('fee-per-script' or FPS scheme) and is administered by independently paid NGO (non-governmental organization) staff; the other uses local shops as a means of supplying drugs. The new scheme was associated with a rise in average daily attendance from nine to thirty-two patients a day (a 240% increase) when compared to a similar period the previous year. Fewer drugs were prescribed in the FPI scheme (average per patient 1.8 vs. 2.4, Chi square P <0.001). The average cost of a drug from the user's perspective was approximately 12% lower in the FPI scheme. These factors combined to make the average cost to the patient of a prescription half that of one in the FPS scheme. The new scheme was 24% cheaper to run on a 'cost per patient' basis when compared with the FPS scheme. However, the overall subsidy needed for the scheme to operate was higher because of the big increase in attendance. One-off stocktakes of ten essential drugs were used to assess the availability of drugs for patient use. The proportion of these drugs that were in low supply or absent was 24% in the FPI scheme. This was similar in the other two schemes. The government DPHO did not perform all the administrative tasks required. These tasks need to be simplified and different methods for involving DPHO staff in drug scheme management need to be explored. The rapid turnover of senior staff, however, will remain a major impediment. This preliminary evaluation shows that an FPI scheme promotes a more rational use of resources, compared to an FPS scheme. Administration of the scheme may, however, prove to be more difficult. A simple field-based comparative assessment of drug supply schemes can give a valuable insight into the strengths and weaknesses of a new programme.

Financing, Government↗
PubMed1991

Insulin oedema: an uncommon complication of insulin therapy.

A 45 year old markedly underweight man presented with polydipsia, polyuria and tingling sensation in both lower limbs of one month duration. Following insulin treatment, he developed gross fluid retention (peripheral oedema and puffiness of face) and a weight gain of 1.8 kg. The oedema occurred on the 3rd day after starting treatment and disappeared on the 7th day without the use of diuretics. Insulin oedema is an uncommon complication of insulin which may occur on introduction of insulin therapy or on increasing the dose, and may be due to the effect of insulin on vascular permeability and renal tubules.

Diabetes Mellitus↗
PubMed1989

Spinal traumas: some postoperative complications in experimental animals.

Animals with severe spinal traumas show paraplegic syndrome and various somatic and autonomic dysfunctions. Of the various dysfunctions those related to hypothermia, bladder problems, and autophagia are of serious nature. The condition of animals with these complications deteriorates rapidly, and the animals are sacrificed for histological and pathological analyses. The findings show that the postoperative complications are related to the degree of severity of the trauma, and that 50-80% animals are lost due to these complications. Most of these animals are lost during the first two weeks after surgery, and the remaining at later stages. Transplantation of neural tissue at the site of lesion does not ameliorate these postoperative complications and improve the survival rate of the animals.

Animals↗