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Biomedical subjects

P K Verma

Publications and source records attributed to P K Verma.

At least 19 recordsLinked to original sources
PubMed2001

Involvement of plasmid in degradation of pentachlorophenol by Pseudomonas sp. from a chemostat.

Pseudomonas sp. strain IST103 obtained from a stable bacterial consortium was capable of utilizing pentachlorophenol (PCP) as sole carbon and energy source. The consortium was developed by continuous enrichment in a chemostat. The degradation of PCP by bacterial strain proceeded through an oxidative route as indicated by accumulation of tetrachloro-p-hydroquinone and chlorohydroquinone determined by high performance liquid chromatography (HPLC), and chloride molecules released in culture medium. Two different molecular size plasmids, of approximately 80 and 4 kilobase, were found to be responsible for carrying genes for degradation of PCP. This was evidenced by mutants produced by curing of plasmid by treatment of ethidium bromide. The derivatives were not able to utilize PCP, however, transformation of low molecular size plasmid of Pseudomonas sp. strain 103 into E. coli JM109 utilized PCP, indicated a possible involvement of plasmid in degradation of pentachlorophenol.

Biodegradation, Environmental↗
PubMed2000

Grading of cerebral autoregulation in preterm and term neonates.

The response of cerebral blood flow velocity to a single spontaneous transient rise in blood pressure was studied to grade the cerebral autoregulatory response of newborns. Blood pressure was measured continuously through an umbilical or peripheral arterial catheter; continuous flow velocity recordings were taken from the middle cerebral artery using continuous wave Doppler ultrasound. From a cohort of 62 healthy term and preterm neonates, 325 transients in mean arterial blood pressure and mean cerebral blood flow velocity were identified for analysis using a foot-seeking algorithm. An initial classification of active or impaired autoregulation was given to each transient using a self-clustering technique. The grading of the transients was studied by examining the slope of the return of the cerebral blood flow velocity to baseline. Negative slopes indicate a normal autoregulation; slopes of 0 or greater indicate an absence of autoregulation. This classification was in agreement with the self-clustering method (Cohen's kappa = 0.94, P<0.0001). The relationship between the autoregulatory response assessed by the grading method and gestational age, postnatal age, and PCO(2) was examined using linear regression analysis. A significant relationship with gestational age (P = 0.002) but not PCO(2) (P = 0.06) or postnatal age (P = 0.14) was evident.

Blood Flow Velocity↗
PubMed2000

Effect of vitamin E supplementation on circulating cell adhesion molecules pre- and post-coronary angioplasty.

The soluble adhesion molecules P-selectin (sP-selectin) and intercellular adhesion molecule-1 (sICAM-1) are derived from platelets and endothelial cells. Circulating concentrations of these soluble adhesion molecules are raised in patients with atherosclerosis and following percutaneous transluminal coronary angioplasty (PTCA). We have investigated the effects of vitamin E supplements (800 IU/day) on circulating plasma ICAM-1 and P-selectin levels pre- and post-PTCA. Patients, randomized to group, were pre-treated with vitamin E or placebo (soybean oil) for 1 month before routine PTCA. Plasma sICAM-1 and sP-selectin were measured by enzyme-linked immunosorbent assay on blood taken immediately pre- and post-PTCA. Total protein and alpha-tocopherol were measured on the same samples. Plasma alpha-tocopherol concentrations increased in patients receiving vitamin E: 19.1 (1.5) [mean (standard error of the mean, SEM)] mg/mL post-PTCA versus 13.9 (0.6) mg/mL pre-PTCA (n=23; P<0.01). Plasma sP-selectin and sICAM-1 levels were not significantly increased following PTCA in the vitamin E group. Pre-angioplasty mean (SEM) plasma sP-selectin concentration in the vitamin E group was 8.83 (0.97) ng/mg protein; the corresponding mean post-angioplasty value was 9.34 (0.89) ng/mg protein (P=0.85). The mean (SEM) pre-angioplasty sICAM-1 concentration in this group was 2.18 (0.24) ng/mg protein, and was 2.20 (0.23) ng/mg protein following angioplasty (P = 0.84). In the placebo group (n = 24) there was a significant increase in mean (SEM) sP-selectin concentration following angioplasty, from 7.48 (0.73) to 9.70 (0.78) ng/mg protein (P<0.05). The change (mean, SEM) in plasma sP-selectin concentration following angioplasty was significantly greater for the placebo group [2.22 (0.50) ng/mg protein] than for the group receiving vitamin E [0.50 (0.50) ng/mg protein] (P<0.02). This difference remained significant (P<0.05) even after adjustment for pre-angioplasty P-selectin concentrations. Mean (SEM) plasma sICAM-1 concentrations remained unchanged following angioplasty [pre-angioplasty: 2.16 (0.20) ng/mg protein; post-angioplasty: 1.97 (0.13) ng/mg protein]. Vitamin E may therefore limit platelet or endothelial activation during PTCA.

Adult↗
PubMed1999

Chronic haemoptysis as delayed complication of ventricular aneurysmectomy.

Two patients developed a ventriculo-pulmonary fistula several years after original resection of a left ventricular aneurysm. Both presented with chronic mild haemoptysis. In the first case mild haemoptysis lasted nearly 19 months, and despite a battery of non invasive and invasive investigations, diagnosis was ultimately made via exploratory thoracotomy. In the second case mild haemoptysis lasted four months and finally manifested as a large haemoptysis. Diagnosis was made preoperatively using echocardiography. We recommend the use of echocardiography when haemoptysis occurs in a patient with a previous history of ventricular aneurysm repair.

Aged↗
PubMed1999

Transcatheter device closure of ventricular septal defects: immediate results and intermediate-term follow-up.

BACKGROUND: Transcatheter closure is an accepted mode of treatment in selected cases of congenital heart disease. Lately, this technology has been applied to closure of ventricular septal defect (VSD). METHODS AND RESULTS: We performed percutaneous transcatheter closure of VSD in 30 patients. The location of VSD was perimembranous in 28 patients and muscular trabecular in 2. Two (7%) patients also had left ventricular-right atrial communication. There were 17 male subjects and 13 female subjects, with an age range of 5. 5 to 33 years (mean +/- SD, 12.9 +/- 5.7; median 12.2). The diameter of VSD ranged from 3 to 8 mm (mean +/- SD 4.7 +/- 1.3; median 4.5). In 5 (17%) patients, the pulmonary to systemic blood flow (Qp/Qs) was >/=2.1 (range 2.0 to 2.6). The defect was at least 6 or 8 mm from the aortic valve in patients in whom a 12- or 17-mm Rashkind double umbrella device was deployed, respectively. In 1 patient, the defect was closed with a detachable stainless steel coil, size 8 mm, with 4 loops (8 x 4). The devices were successfully deployed in 87% of patients. In 6 (20%) patients, the procedure had to be repeated primarily because of the use of undersized umbrella deices. Unsuccessful deployment of the device occurred in 4 (13%) patients. In one of these procedures, the coil embolized to the left pulmonary artery, and it was successfully retrieved. A minimal residual shunt seen as a thin streak on transthoracic color flow mapping persisted in 8 (30%) patients, which remained unchanged over a follow-up period of 5 to 28 (17.1 +/- 6.4) months. Both patients with left ventricular/right atrial communication showed complete abolition of the shunt. No patient developed new-onset aortic or tricuspid regurgitation or intravascular hemolysis. At follow-up, no patient had developed infective endocarditis, bundle branch block, or late valvular insufficiency. CONCLUSIONS: Transcatheter closure is safe and efficacious in selected cases of perimembranous and muscular VSD.

Adolescent↗
PubMed1999

Transcatheter closure of ventricular septal defect using detachable steel coil.

Transcatheter closure has been attempted in selected cases of ventricular septal defects using Lock clamshell device, Rashkind umbrella device, and Sideris buttoned device. A small perimembranous ventricular septal defect with aneurysm of membranous septum in a 12 year old girl was closed successfully with a detachable steel coil of 8 mm diameter with four loops, after failure of deployment of a Rashkind double umbrella device.

Child↗
PubMed1998

A multiplex RT-PCR assay for analysis of relative transcript levels of different members of multigene families: application to Arabidopsis calmodulin gene family.

The high degree of conservation of nucleotide sequences among different members of a multigene family poses problems in analysis of expression patterns governed by each member of the gene family. In this report we describe a simple, semi-quantitative and single tube multiplex RT-PCR assay for simultaneous and relative expression analysis with an application to all the six members of Arabidopsis calmodulin multigene family. In the multiplex primer set, individual gene specific primers were derived from 3'-untranslated region of the genes and a single common primer from the conserved exonic region. Transcriptional activation of all the members of the calmodulin gene family in response to touch was monitored. The results demonstrate that two of the genes are not regulated by touch; however, the other four that are induced by touch show a differential response including their kinetics of induction.

Arabidopsis↗
PubMed1997

Visual and auditory evoked responses in acute severe hepatitis.

Evoked responses have not been studied in patients with acute severe hepatitis (ASH) with or without hepatic encephalopathy. This prospective study was undertaken to find out diagnostic as well as prognostic value of visual evoked responses (VER), and brain stem auditory evoked responses (BAER) in patients with ASH with or without encephalopathy. Visual evoked responses and BAER were studied in 20 patients (14 males and six females) with ASH. The patients were diagnosed as having severe hepatitis if acute hepatitis was associated with raised serum bilirubin and serum transaminases, and if they had a prothrombin time index of < 50%. After a detailed neuropsychiatric examination of each patient, the study sample was divided into two groups of 10 patients: ASH without encephalopathy (ASH-WOE), and ASH with encephalopathy (fulminant hepatic failure, FHF). The median P100 latencies of FHF patients were significantly increased compared with controls and patients in the ASH-WOE group. Abnormal P100 latencies, exceeding 95th percentile values of the controls, were present in one patient in the ASH-WOE group and six patients in the FHF group. The median interpeak latencies I-III, III-V and I-V were significantly prolonged in the FHF group. Interpeak latencies III-V were also increased significantly in patients in the ASH-WOE group. While abnormal BAER were seen frequently in both groups, VER abnormalities were largely confined to patients in the FHF group. In the FHF group, six out of 10 patients survived and exhibited clinical improvement in the status of hepatic encephalopathy. Evoked responses were repeated after 2-3 weeks of recovery in these patients and VER abnormalities showed a tendency to normalize, thereby suggesting a prognostic implication. The incidence of abnormal VER in hepatic encephalopathy complicating ASH far exceeded that of abnormal BAER. Markedly prolonged P100 latencies in FHF patients indicate poor prognosis.

Acute Disease↗
PubMed1997

[Use of PTCA in a gastroepiploic aortocoronary graft].

The use of the gastroepiploic inferior artery as an aortocoronary graft is at present a method of third choice after the mammary artery and venous grafts in revascularizations of the heart muscle. The results are comparable with those obtained with the mammary artery. With regard to the increasing number of operations are more plentiful on the development of atherosclerosis of the above mentioned graft. This dumps the initial enthusiasm that in this artery atherosclerosis does not develop. Reports on PTCA, when this artery is affected, are so far rate. The authors performed a successful PTCA of this graft in a patient with complete affection of the coronary circulation where alternative possibilities of revascularization of the heart muscle were practically exhausted. To improve the technique a suitable type of catheter must be developed which will make it possible to overcome technical problems associated with cannulation of artery and its dilatation.

Angioplasty, Balloon, Coronary↗
PubMed1993

LDH-x in azoospermia: a new diagnostic alternative to vasography and testicular biopsy.

Activities of different isozymes of lactate dehydrogenase were studied in semen samples from fertile, and different groups of infertile men. No isozyme except the sperm specific LDH-x or C4 showed any difference in activity with changes in sperm density. Activity of LDH-x exhibited a trend positive to changes in sperm density and became absent in obstructive and vasectomized azoospermia. Among other types of azoospermia, the activity became very high in maturation arrest but very low in patients with testicular biopsy showing germ cell aplasia, such as in SCOS and ghostlike tubules. Diagnostic usefulness of the estimation of LDH-x activity in semen is discussed.

Biopsy↗
PubMed1993

Modifications in the seminal protein pattern and concentration among infertile men.

Lower concentrations of protein observed in semen of infertile men were mostly due to absence of vesicular proteins with higher isoelectric pH above pH 8.3. Two to four proteins with lower isoelectric pH showing electrophoretic mobility and originating both from seminal vesicle and prostate were absent in infertile semen samples. Concentrations of such proteins among oligozoospermic and azoospermic samples with complete maturation arrest and Sertoli cell only syndrome decreased mainly towards cathode, whereas, in vasectomized azoospermia the number of protein bands decreased both towards cathode and anode, though the concentration decreased mainly in the anodic proteins.

Electrophoresis↗
PubMed1992

Optimization of the electric field distribution in a large volume tissue-equivalent proportional counter.

Large volume tissue-equivalent proportional counters are of interest in radiation protection metrology, as the sensitivity in terms of counts per unit absorbed dose in these devices increases as the square of the counter diameter. Conventional solutions to the problem of maintaining a uniform electric field within a counter result in sensitive volume to total volume ratios which are unacceptably low when counter dimensions of the order of 15 cm diameter are considered and when overall compactness is an important design criterion. This work describes the design and optimization of an arrangement of field discs set at different potentials which enable sensitive volume to total volume ratios to approach unity. The method has been used to construct a 12.7 cm diameter right-cylindrical tissue-equivalent proportional counter in which the sensitive volume accounts for over 95% of the total device volume and the gas gain uniformity is maintained to within 3% along the entire length of the anode wire.

Electromagnetic Fields↗
PubMed1992

Seronegative generalized myasthenia gravis: low frequency of thymic pathology.

We have reviewed thymus histology, preoperative serum acetylcholine receptor antibody status, and clinical features of all 50 patients who underwent thymectomy for generalized myasthenia gravis in the University of British Columbia-affiliated hospitals over the last 8 years. Seven patients had thymoma, 25 had hyperplasia, and 18 had a normal thymus. The seven thymoma patients all had severe limb involvement and all had circulating antibodies against the acetylcholine receptor. Patients without circulating antibodies had only minimal limb involvement and half of them had a normal thymus. Only two of the 32 (6%) patients with abnormal thymus were antibody-negative; this contrasts with six of the 18 patients (33%) with normal thymus. We conclude that seronegative patients with generalized myasthenia gravis constitute a distinct subgroup which may not be immunologically homogeneous and could be subgrouped with normal or abnormal thymic histology.

Adolescent↗
PubMed1989

Massive lymphadenopathy in chronic myelocytic leukemia.

A 50 year old male presented with massive lymphadenopathy and was found to be in extramedullary blast crisis is reported. Lymphadenopathy regressed on busulphan therapy and the overt blast crisis took 15 months to occur after initial presentation.

Bone Marrow↗