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Biomedical subjects

U Prakash

Publications and source records attributed to U Prakash.

18 recordsLinked to original sources
PubMed2001

Computerised measurement of tibiofemoral alignment.

Tibiofemoral alignment has a direct correlation with the survival of total knee arthroplasty. Traditionally, it has been measured using a goniometer on radiographs. We describe new software which measures this alignment on scanned radiographs by automatically detecting bones in the image. Two surgeons used conventional methods and two clerical officers used the computerised routine to assess 58 radiographs of the knee on two occasions. There were no significant differences between any of the paired comparisons. The largest mean difference detected was 1.19 degrees. Across all comparisons, the mean correlation was 0.755. A standardised routine for measuring tibiofemoral alignment was the greatest factor in reducing error in our study. These results show that non-medical staff can reliably use the software to measure tibiofemoral alignment. It has the potential to measure all the parameters recommended by the Knee Society.

Algorithms↗
PubMed1999

Effect of activity levels on polyethylene wear in Charnley low-friction arthroplasty.

Polyethylene wear debri has been implicated as a major cause of aseptic loosening following total hip replacement. The purpose of this study is to classify patient activity levels following total hip replacement and determine if it has an effect on radiographic wear of the socket. 97 patients (115 hips) with osteoarthritis who underwent Charnley low-friction arthroplasty with a minimum of 10 year follow-up were selected. Nine patients had died. Eighty-eight questionnaires were sent of which 59 replied. However, only 40 patients (45 hips) with a complete set of x-rays were finally studied. Activity levels were classified according to post-operative occupation and activities into 'active' and 'less active' groups. Radiographic wear was measured by studying the post-operative and the 10-year review radiograph. There was a significant difference in acetabular wear between the active and the less active group (p = 0.024). No correlation was found between weight and acetabular wear (p = 0.475) or between age and acetabular wear (p = 0.278). It was concluded, therefore, that surgeons who advise their patients to avoid heavy or high intensity activities for prolonged periods, after Charnley low-friction arthroplasty, are justified in this approach.

Acetabulum↗
PubMed1998

The epidemiology of open long bone fractures.

Open long bone fractures occur with a frequency of 11.5 per 100,000 persons per year. They are more common in males and they have a bimodal age distribution. Open fractures of the tibial diaphysis are the commonest, but open femoral diaphyseal, distal femoral and proximal tibial fractures tend to occur in the most seriously injured patients. Lower limb open fractures are more severe than open fractures of the upper limbs. Not only is the soft tissue damage less in open upper limb fractures, but there are fewer associated musculoskeletal injuries.

Accidents, Traffic↗
PubMed1997

H-reflex latency: a maturity criterion for newborn babies.

One hundred newborn babies were investigated for H-reflex latency (H-RL) in between 33 to 40 weeks (wk) of post-conceptional age (PCA). Weekly data of both preterms (33 to 36 wk PCA) and fullterms (37 to 40 wk PCA) were compared. A significant reduction in H-RL was noticed at 37 wk PCA when newborns attain their term. The babies could be classified into preterms and fullterms by using their H-RL values.

Analysis of Variance↗
PubMed1995

Electrophysiological studies in children with paralytic poliomyelitis.

H-reflex latency (H-RL) and H/M ratio were measured in normal children and children with paralytic poliomyelitis of 1-3 years of age. The H-RL was considerably increased in both the involved and uninvolved limbs of the patients, whereas the H/M ratio did not differ. The Mmax value in the involved limb was very low, and therefore, a corrected H/M ratio was calculated for that side only. The corrected H/M ratio was significantly less than the H/M ratio observed in the uninvolved and control limbs. The distal motor latency was also increased in the involved side.

Child, Preschool↗
PubMed1994

Electrophysiological studies (MNCV and H-RL) in twin babies.

Twenty-six fullterm and eight preterm babies born of twin pregnancies were studied. Offsprings were subjected to measurements of weight, crown heel length and head circumference along with motor nerve conduction velocity (MNCV) and H-reflex latency (H-RL) at right median nerve. The preterm twins had significantly lower MNCV and higher H-RL. The electrophysiological parameters did not vary in first and second born twins as well as in heavier and lighter twins. Three pairs of twins were available for follow-up study.

Birth Weight↗
PubMed1993

Motor nerve conduction velocity & Hoffman's reflex latency in newborns.

A total of 72 newborns and their mothers were studied to assess the influence of various variables on the motor nerve conduction velocity (MNCV) and Hoffman's reflex latency (H-RL) of the babies with a view to differentiate fullterm and preterm low birth weight babies. MNCV were significantly lower and H-RL significantly higher in preterm appropriate for gestational (PT-AGA) age babies compared to fullterm appropriate for gestational age (FT-AGA) and fullterm intrauterine growth retarded babies (FT-IUGR). In FT-IUGR babies, only MNCV was significantly reduced as compared to FT-AGA babies.

H-Reflex↗
PubMed1993

Electrophysiological studies in preterm and growth retarded low birth weight babies.

Twenty-six fullterm intrauterine growth retarded (FT-IUGR) and 17 preterm appropriate for gestational age (PT-AGA) babies constituted study subjects. Offsprings were subjected to anthropometry (weight, crown-heel length and head circumference) and motor nerve conduction velocity (MNCV) as well as H-reflex latency (H-RL) at right median nerve. The PT-AGA babies had significantly lower MNCV and higher H-RL compared to FT-IUGR babies. When intrauterine growth retardation was severe (weight group 1500-1800 g) the means for MNCV and H-RL between FT-IUGR babies and PT-AGA babies of comparable weight were similar. FT-IUGR babies weighing between 1800-2100 g had significantly higher MNCV and lower H-RL compared to FT-IUGR babies weighing < 1800 g. The FT-IUGR babies where all the three anthropometric parameters were retarded (symmetrical intrauterine growth retardation) had significantly lower MNCV and higher H-RL compared to FT-IUGR babies where weight alone or in combination with crown-heel length was retarded.

Birth Weight↗
PubMed1989

Electrophysiological studies (MNCV, H-RL) in full-term newborn babies.

Twenty-five full-term newborns and their mothers constituted study subjects. Mothers were subjected to weight and height measurements, as well as, serum albumin and hemoglobin estimations. Offsprings were subjected to measurements of weight, crown heel length and head circumference along with motor nerve conduction velocity (MNCV) and H-reflex latency (H-RL). The MNCV was found to be significantly lower in growth retarded (FT-IUGR) babies compared to appropriately grown babies (FT-AGA) whereas H-RL was similar in both FT-IUGR and FT-AGA babies.

Electrophysiology↗
PubMed1979

Nature of human serum blood group T antibodies.

Antibodies against blood group substance T in normal human sera consist of two types, depending upon whether or not the molecules remain immunochemically active at 37 degrees C. The two agglutinins were isolated by means of T antigen-coupled Sepharose 48 affinity chromatography. Temperature-sensitive agglutinin was eluted from the affinity column at 37 degrees C, while temperature-independent agglutinin remained bound to the antigen. Subsequently, the latter was dissociated from the column in the presence of 2.5 M MgCl2. Examination of six normal sera revealed that the levels of temperature-independent agglutinin was about twice that of temperature-sensitive agglutinin. More than 90% of anti-T agglutinins in normal sera were of the IgM class, in 8 of 11 samples studied. No direct relationship appeared to exist between anti-T titers and blood type. Thermal effects on hemagglutination, at least for anti-T agglutinin interacting with T antigen bearing red cells, is primarily due to the molecular characteristics of the agglutinin and not to the conformational change of the red cell membranes.

Adsorption↗
PubMed1978

Simultaneous determination by GC-MS-SIM of o-, m-, p-hydroxyphenylacetic acid, 3:4-dihydroxyphenylacetic acid and homovanillic acid in biological samples using a common selected ion.

A GC-MS-SIM method is described for the simultaneous determination of five acid metabolites, o-, m-, and p-hydroxyphenylacetic acid, 3:4-dihydroxyphenylacetic acid and homovanillic acid in biological samples using a common selected ion for all the acids. The TMS ethers of methyl or ethyl esters of these compounds have a common ion at m/e 179 which is used for their quantitation by selected ion monitoring. The molecular ion at m/e 238 of the three monohydroxy phenylacetic acids, which is also the M-30 ion for homovanillic acid, is also used for their quantitation. The GC conditions for their separation, the relative sensitivities and some advantages of TMS ethers over other derivatives are described. The application of this method to biological samples is illustrated by data on human urine and plasma.

3,4-Dihydroxyphenylacetic Acid↗
PubMedDate not supplied

Birth hypoxia and spinal reflex in newborn babies.

Birth hypoxia is detrimental to neuronal function. In this study, its effect on spinal monosynaptic reflex was investigated on two different age groups of human newborn babies using few non-invasive electrophysiological parameters. A total of 57 newborns (25 hypoxic + 32 non-hypoxic) were the study subject. Out of which, 31 newborns (11 hypoxic + 20 non-hypoxic) were examined within 48 hours of birth, and the rest 26 (14 hypoxic + 12 non-hypoxic) were examined between 48h and 120h (five days) of birth. H-reflex latency (HRL), distal motor latency (DL), and H-reflex conduction velocity (HRCV), were estimated for understanding the transmission of impulse in the monosynaptic reflex pathway. Moreover, Hmax, Mmax, and H/M ratio were observed for studying the spinal motor neuronal excitability. The injurious effect of hypoxia was detected on HRL, HRCV, Hmax and H/M ratio in babies who were examined within 48h of birth. The HRL was significantly increased and other parameters were significantly reduced. In the older group of babies, however, Hmax was the only parameter affected by hypoxia. The relatively older babies of hypoxic or non-hypoxic group had higher Hmax and H/M ratio compared to younger ones of their own group.

Action Potentials↗
PubMedDate not supplied

Electrophysiological studies in newborns with reference to gestation and anthropometry.

Fourteen full term appropriate for gestational age (FT-AGA) and 11 preterm appropriate for gestational age (PT-AGA) newborns and their mothers constituted study subjects. The mothers were subjected to hemoglobin and serum albumin estimations. Offsprings were subjected to measurements of weight, crown heel length and head circumference along with motor nerve conduction velocity (MNCV) and H-reflex latency (H-RL) at right median nerve. The MNCV was found to be significantly lower and H-RL significantly higher in PT-AGA babies compared to FT-AGA babies. The gestation, crown heel length of baby and maternal serum albumin status were found to be significant independent variables. Multiple regression equations have been derived using these parameters as determinative variables. These equations explained much higher per cent variation than explained by simple regression equations.

Action Potentials↗
PubMedDate not supplied

Morphine hyperthermia in rats: role of neurochemical substances in brain.

Central neurochemical mechanism underlying the hyperthermic effect of morphine has been investigated in rats. 200 micrograms morphine hydrochloride, when administered through cerebroventricular route at different seasonal air temperature, caused a rise in rectal temperature of rats. This hyperthermia was not affected by prior administration of antiserotonergic (pCPA, 5.6-DHT) or anticatecholaminergic (PBZ, 6-OHDA) drugs, as well as by PGE synthetase inhibitor, indomethacin. Similarity, cholinergic muscarinic or nicotinic receptor blockers, such as atropine and pentolinium/ D-tubocurarine respectively, were ineffective to modify it. Whereas, the depletion of acetylcholine in brain by pretreating the animals with hemicholinium profoundly delayed the hyperthermia, suggesting a central cholinergic involvement in morphine induced hyperthermia in rats.

Animals↗
PubMedDate not supplied

Studies on rectal temperature of rats in relation to seasonal air temperature and morphine administration.

The present findings demonstrate that seasonal air temperature does not only influence the basal core temperature of rats, but also modifies the physiological/pharmacological actions of drugs. Thus, at low ambient temperature, intracerebroventricular on intraperitoneal administration of morphine produces mainly hypothermia followed by a secondary rise in rectal temperature. On the other hand, at high ambient temperature, the drug produces hyperthermia only. The hypothermic response at low ambient temperature is abolished by pretreatment of rats with 6-hydroxydopamine but not with phenoxybenzamine administration. This suggests that catecholamine pathway in the central nervous system is involved in morphine induced hypothermic response. Further, the role of cholinergic neurons in such response is also indicated.

Animals↗