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Biomedical subjects

V Saxena

Publications and source records attributed to V Saxena.

18 recordsLinked to original sources

Ischemic nephropathy.

Atherosclerotic narrowing of the renal arteries may result in severe consequences including chronic renal ischemia, renal artery atheroembolism and renal vascular hypertension. Ischemic renal disease is increasingly recognised as a potentially treatable cause of chronic renal failure. Its precise prevalence is still poorly determined as there is no population based studies. The patients with ARD, particularly those with high grade stenosis and systolic hypertension are at very high risk for renal atrophy and renal failure. Angiogram is usually required to confirm the diagnosis. However, the diagnosis is likely in the elderly patient with systemic atherosclerosis and hypertension in whom a rapid rise in serum creatinine concentration is associated with decreased renal length. Disease is associated with high mortality when treated medically. In contrast, clinical improvement is reported after renal revascularisation. Therefore, consider the diagnosis in the patients at risk, because revascularisation (surgical or endovascular) can successfully preserve renal function in selected patients.

Arteriosclerosis↗

Guanidino compounds in serum and urine of cirrhotic patients.

To investigate the metabolic relationship between urea and guanidinosuccinic acid (GSA), we determined the levels of the guanidino compounds, including GSA, and urea in serum and urine of cirrhotic patients. Linear correlation studies between serum urea and GSA levels were performed. Good positive linear correlation coefficients were found in the Child-Turcotte C subgroup (r = .847, P < .001) and in the total subgroup including B and C patients (r = .848; P < .0001). Serum guanidinoacetic acid levels were significantly increased in the Child-Turcotte C subgroup (P < .0001 for men and P < .001 for women). In contrast, GSA levels were significantly (P < .0001) decreased in the three studied subgroups. Similar results were found for urinary GSA excretion levels. Within each subgroup, serum and urinary GSA levels were significantly lower in patients with alcohol-induced cirrhosis than in nonalcoholic cirrhotic patients. Similar results were obtained for urea. The findings in cirrhotic patients clearly demonstrate a metabolic relationship between urea and GSA. They also show that urea and GSA biosynthesis is significantly lower in cirrhotic patients with an alcoholic origin than in cirrhotic patients with a nonalcoholic origin.

Adult↗

Calculation of monitor units for a linear accelerator with asymmetric jaws.

A simple approach was developed that calculates the output factors and tissue maximum ratio of an asymmetric field at any point within the open field, and specifically both at the central axis (when the jaws do not shadow it) and at the effective center of the open field, using the existing tables for symmetric fields and the multidepth profile information for the largest available field size (either open or with a wedge present). Day's method was adapted to calculate the effective values of the usual field-size-dependent parameters. This approach makes these parameters also dependent on the location of the calculation point relative to the field edges in an asymmetric field. This algorithm was tested by comparing its predictions with measurements of asymmetric and half blocked fields, with and without wedges, in a water phantom at different depths and off-axis distances. The agreement between calculated and measured dose rate is within 1%-3% even in highly asymmetric fields for both 6- and 18-MV photons.

Models, Structural↗

Chronic colchicine-induced myopathy and neuropathy.

The presented case concerns a 77-year old man who had been chronically taking colchicine for treatment of gout. He was admitted because of a transient ischemic cerebrovascular attack with motor aphasia and complained of preexisting paraesthesias in the lower extremities. Neurological examination revealed a global muscular weakness, absent myotatic reflexes and a diminished sensation. Serum creatine kinase (CK) levels were increased and electromyography showed spontaneous fibrillations in deltoid muscles, positive spikewaves in deltoids and anterior tibial muscles. Motor and sensory conduction velocities were mildly reduced. Nerve biopsy findings were compatible with a chronic axonal neuropathy having produced a significant loss of myelinated axons and also denervation features of unmyelinated axons. In muscle, combined neurogenic and myogenic features were found. The former result from the axonal neuropathy. The latter were mainly characterized by focal myofibrillar disorganisation and accumulation of autophagic vacuoles in muscle fibres. The presented neuromuscular symptoms and signs, the increased CK values, the electromyographic and nerve conduction velocity findings as well as nerve and muscle biopsy observations, are consistent with the diagnosis of colchicine-induced myopathy and neuropathy. Furthermore, the disappearance of paraesthesias, normalisation of CK values, and disappearance of fibrillations and positive spike waves in deltoid and anterior tibial muscles on electromyography, after stopping of the colchicine therapy, supported the diagnosis.

Aged↗

Role of calcium in induction of dengue virus-specific helper T cells.

Dengue type 2 virus (DV) induces the generation of T helper cells (TH) in the mouse spleen. These TH on adoptive transfer to DV primed syngeneic mice enhance the clonal expansion of antigen-specific antibody plaque forming cells. The present study was undertaken to investigate the role of M phi and Ca2+ in the induction of DV-specific TH. The results show that M phi are obligatory for the induction of DV-specific TH. It was observed that DV antigen stimulate the influx of calcium ion (Ca2+) into T cells as shown by radiolabelled (45Ca) and the influx of Ca2+ increases with time of incubation, reaching a maximum level after 1 hr of incubation. The proliferation of T cells was found to be dependent on presence of Ca2+ as it was inhibited by Ca channel blocking drugs and in the absence of Ca in the medium. Thus showing that Ca2+ plays an important role in the induction of DV-specific TH cells.

Animals↗

Carcinoma of the nasopharynx: survival and patterns of recurrence.

We have analyzed survival, disease-free (NED) survival, and patterns of recurrence for 76 patients with carcinoma of the nasopharynx treated from June 1964 through July 1979. Patients with Stages I through IV, who were treated for cure, comprise the study group. Megavoltage teletherapy treatment was delivered to the primary bilateral neck and supraclavicular areas. Dose to the nasopharynx ranged from less than 55 Gy to 70 Gy with several patients receiving higher doses. The observed 5 year NED survival rates were: Stage I, 75%; Stage II, 20%; Stage III, 42%; and Stage IV, 31%. During a 5-year minimum follow-up for all patients, 46 or 60.5% failed. Ninety-five percent of these failures occurred within 3 years; only two patients relapsed after more than 5 years.

Adolescent↗

Extranodal non-Hodgkin's lymphoma.

From 1964 to 1977, 42 patients with Stages I and II non-Hodgkin's lymphoma involving the extranodal sites were seen and treated with curative intent by radiotherapy in the Department of Therapeutic Radiology at Rush-Presbyterian-St. Luke's Medical Center. The initial pathologic specimen was reclassified according to the criteria of Rappaport et al. Diffuse histology was the most common histologic type found in 80% of the patients. The five-year actuarial survival and disease-free survival rates were found to be almost identical at 74% for Stage I and 38% for Stage II patients. The most common sites of origin were in the head and neck area in 19 patients and gastrointestinal tract in 15 patients. The sites of involvement in the head and neck area were many and varied, with parotid and nasal cavity being the most frequent. Survival rates and disease-free survival rates for different histologic types, various sites, and their patterns of recurrence are presented.

Gastrointestinal Neoplasms↗

"In vivo", effectivity of codeine sulfate on the meiotic chromosomes of Saccobranchus fossilis.

Codeine sulfate which is obtained from opium or made by methylating morphine has been found to induce a number of anomalies in the meiotic chromosomes of S. fossilis. Feulgen technique was undertaken for experimental studies. At high doses abnormal metaphases, agglutination, achromatic lesions, some breaks and chromosomal scattering were evident. However, the frequency of abnormal metaphases was high amongst the rearrangements. The susceptibility of meiotic metaphase during peak period of breeding is indicative of inhibition in the division activity.

Animals↗

Chlorpromazine induced anomalies in Saccobranchus fossilis.

Cytomorphological implications studied after the inducement of chlorpromazine included various anomalies like precocious despiralization, stickiness, breaks and pseudobridges. It is certain that CPZ has the capability of depolymerizing the DNA contents of the germ cells of S. fossilis.

Animals↗

"In vivo", testosterone propionate induced aberrations in Notopterus notopterus.

Germ cell chromosomes of N. notopterus responded ot the higher doses of testosterone propionate peculiarly. Emergence of anomalies like agglutination at terminal ends, clumping and precocious despiralization was evident. The stickiness, breaks, laggard and a few achromatic lesions also appeared. Effect up to 72 hrs stages was evincible and varying occurrences of chromosomal irregularities.

Animals↗

Studies on the effects of O-isopropoxyphenylmethyl carbamate on the meiotic chromosomes of Saccobranchus fossilis.

O-isopropoxyphenylmethyl carbamate in S. fossilis chromosomes has been found to induce fragmentation at pachytene and diakinesis. Fragmentation frequency increased with the increase in dose. The yield of total clumping at different doses and different intervals was inconsistent. Precocious despiralization and stickiness were also observed. Time interval was observed to be a factor in the appearance of anomalies with different doses. The dicentric bridges which were frequent at low dose, diminished in quantum with the increase in dose.

Animals↗

Anti-implantation activity of some indigenous plants in rats.

Various extracts of one hundred and eight medicinal plants were screened for their anti-implantation activity in female albino rats. Out of these, 50% ethanolic extract of Codonospis ovata Benth (PL); 50% ethanolic, acetone and benzene extracts of Puararia tuberosa DC (TUB); aqueous and methanolic extracts of Punica granatum Linn. (PX) and ethanolic and acetone extracts of Rubus ellipiticus Smith (PX) inhibited pregnancy in 70-90% of rats. Similarly ethanolic extract of Adhatoda vasica Nees (LF) and Kigelia pinnata DC (PL); ethanolic and acetone extracts of Acrostichum aureum Linn. (PL), Juniperus communis Linn. (SD), Lepidium capitatum H.f. & T. (PL); ethanolic and benzene extracts of Citrulus colocynthus Schrad (LF) and acetone extract of Codonopsis ovata Benth (PL) showed 60-70% anti-implantation activity. Extracts of a few plants VIZ. Dolichos biflorus Linn. (SD), Ferule orientalis Linn. (PL), Nerium odoratum Lamk (RT), Randia dumetorum Lamk (SD) and Ruta graveolens Linn. (PL) could inhibit pregnancy in 50-60% of rats. The rest of the plants were either inactive or showed insignificant antifertility activity.

Animals↗

Contraceptive potency of Pueraria tuberosa D.C. and its hormonal status.

A medicinal plant, Pueraria tuberosa D.C. has been thoroughly investigated for its contraceptive potency in various animals viz. rats, mice and hamsters. The activity has been further confirmed with respect to its habitat and seasonal variations. The potent fractions have been studied for their biological properties so as to elucidate its exact hormonal status. The observations suggest that tubers of P. tuberosa D.C. possess significant antifertility activity. The contraceptive efficacy does not alter significantly with respect to the change in time and place of collection. Its crude powder, ethanolic aand butanolic extracts evoke a significant antifertility activity in rats, mice and hamsters whereas hexane, chloroform, methanol, petroleum ether and benzene extracts are significantly effective to prevent implantation only in rats and mice. Aqueous extract does not show any significant antifertility activity in all these three animal species. The studies on its biological properties suggest that all the fractions of P. tuberosa D.C. possess significant estrogenic activity. In addition to this activity, the crude powder also shows significant progestational and mild antiprogestational activity whereas ethanolic and butanolic extracts show significant progestational activity. Petroleum ether and benzene extracts show only the estrogenic activity. The biological properties and their differences in activity have been discussed in relation to antifertility mode of action of P. tuberosa.

Animals↗