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Biomedical subjects

V K Shukla

Publications and source records attributed to V K Shukla.

At least 19 recordsLinked to original sources
PubMed1992

Selective involvement of kappa opioid and phencyclidine receptors in the analgesic and motor effects of dynorphin-A-(1-13)-Tyr-Leu-Phe-Asn-Gly-Pro.

Dynorphin A-(1-13)-Tyr-Leu-Phe-Asn-Gly-Pro (Dyn Ia; 1-8 nmol) injected intracerebroventricularly in the mouse produces two independent behavioral effects: (1) a norbinaltorphimine (kappa opioid antagonist)-reversible analgesia in the acetic acid-induced writhing test and (2) motor dysfunction characterized by wild running, pop-corn jumping, hindlimb jerking and barrel rolling and antagonized by the irreversible phencyclidine (PCP) and sigma (sigma) receptor antagonist, metaphit and the non-competitive N-methyl-D-aspartate (NMDA) receptor antagonists, dextromethorphan and ketamine. The specific involvement of the PCP receptor in the motor effects of Dyn Ia is supported by the direct competitive interaction of the peptide with the binding of [3H]MK-801 (Ki: 0.63 microM) and [3H]TCP (Ki: 4.6 microM) to mouse brain membrane preparations.

Amino Acid Sequence↗
PubMed1992

The D1 protein of the photosystem II reaction-centre complex accumulates in the absence of D2: analysis of a mutant of the cyanobacterium Synechocystis sp. PCC 6803 lacking cytochrome b559.

The reaction center core of photosystem II, a multiprotein membrane bound complex, is composed of a heterodimer of two proteins, D1 and D2. A random mutagenesis technique was used to isolate a photosystem II deficient mutant, CP6t16, of the unicellular cyanobacterium, Synechocystis sp. PCC 6803. Nucleotide sequence analysis showed that the primary lesion in CP6t16 is an ochre mutation introducing a translational stop codon in the psbE gene, encoding the alpha-subunit of cytochrome b559, an integral component of the PSII complex. Analysis of the protein composition of CP6t16 thylakoid membranes isolated in the presence of serine protease inhibitors revealed that, in the absence of cytochrome b559, the D2 protein is also absent. However, the D1 protein is stably incorporated in these membranes, suggesting that the synthesis and integration of D1 are independent of those of D2 and cytochrome b559.

Base Sequence↗
PubMed1992

Central non-opioid physiological and pathophysiological effects of dynorphin A and related peptides.

Dynorphin A (Dyn A) and related opioid peptides derived from prodynorphin possess a high affinity for kappa opioid receptors, but they also bind to other opioid receptors (mu and delta) as well as to some non-opioid receptor sites. Although the physiological role of these peptides is not well established, recent experimental data pinpoint their particular involvement in physiological and pathophysiological conditions that relate to algesia, spinal cord injury and epilepsy. In this paper, we review data which support the concept that the non-opioid behavioral effects of Dyn A and related endogenous peptides which are observed under these conditions are physiologically and pathophysiologically relevant.

Brain↗
PubMed1992

Role of rapid imprint cytology in the diagnosis of skin cancer and assessment of adequacy of excision.

Imprint cytotechnique was employed in 20 cases of maligant skin tumours (11 squamous cell carcinoma, 4 basal cell carcinoma and 5 malignant melanoma) to evaluate the reliability of the technique by comparing the results with histologic diagnosis. In ten cases margins of the excised tumours were also subjected to imprint and histopathologic studies to assess the clearance of malignancy. All the tumours were correctly diagnosed in imprint smears. Similarly 100% cytohistopathologic correlation was also obtained in the assessment of excisional margins of the tumours. The technique of imprint cytology may be employed for quick diagnosis of skin cancers and in assessment of clearance of surgical field during surgery.

Basal Cell Carcinoma↗
PubMed1992

How common are benign subungual naevi?

The differentiation of subungual haematoma from benign and malignant nevoid lesions is a common clinical problem. To determine the incidence of benign subungual naevi in the general population, the digits of the hands and feet of 1000 white patients were examined. These were consecutive patients presenting to hospital for problems unrelated to the finger or toe-nail. Eight patients were found to have pigmented subungual lesions. All proved to be haematoma, although there was no history of injury. Benign subungual naevi are rare in caucasians, so subungual nevoid lesions should be regarded as malignant until proved otherwise.

Adolescent↗
PubMed1991

Serum trace elements and Cu/Zn ratio in breast cancer patients.

Serum copper, zinc, and the Cu/Zn ratio were measured in 55 patients with breast disease (20 with benign breast diseases and 35 patients with breast cancer) and 30 controls. The mean serum copper levels were higher in breast cancer than in benign breast diseases (167.3 micrograms/dl vs. 117.6 micrograms/dl) (P less than 0.001) and controls (167.3 micrograms/dl vs. 98.8 micrograms/dl) (P less than 0.001). Patients with advanced breast cancer had higher serum copper levels than did patients with early breast cancer (177.9 micrograms/dl vs. 130.4 micrograms/dl) (P less than 0.001). The mean serum zinc levels were lowered only in patients with advanced breast cancer as compared with controls (88.6 micrograms/dl vs. 115.1 micrograms/dl) (P less than 0.001). Serum zinc levels were not decreased in patients with early breast cancer and benign breast diseases. The Cu/Zn ratio was increased in breast cancer patients (1.91 vs. 0.86) (P less than 0.001) but not in patients with benign breast diseases. The precise mechanisms responsible for the alterations in trace element levels in breast cancer patients are still unclear and require further evaluation. However, the serum copper levels and the Cu/Zn ratio may be used as biochemical markers in these patients.

Adult↗
PubMed1991

The presence of oxidative polymeric materials in encapsulated fish oils.

Encapsulated health food oils such as fish oils are readily available in health food stores, pharmacies, and supermarkets. They are popular in the United States as well as in the European countries. However, such oils, because of their high degree of unsaturation, are easily oxidized and form complex mixtures of high molecular weight oxidation products. The present work reports the application of high-performance size exclusion chromatography to the determination of these materials in encapsulated fish oils. Of the six samples studied, five showed from 1-10% of dimeric triacylglycerols and one contained 6.3% trimeric triacylglycerols and 3.1% oligomeric triacylglycerols. Further investigation of this sample with silicic acid chromatography indicated that it contained a total of 36.3% polar material.

Capsules↗
PubMed1991

Antagonism of acute cocaine toxicity by buprenorphine.

The effect of buprenorphine pretreatment on the acute cocaine toxicity was assessed in male Swiss Webster mice. Buprenorphine pretreatment (0.15 or 0.30 mg/kg ip, 30 mins before) significantly attenuated the lethal effects of cocaine (60-140 mg/kg ip). The dose of cocaine which resulted in 50% mortality (LD50) in saline pretreated group was 100.61 mg/kg while the LD50 of cocaine in buprenorphine (0.15 and 0.3 mg/kg) pretreated groups were 113.57 and 118.16 mg/kg respectively. There was no significant change in the ratio of brain/plasma levels of cocaine in buprenorphine pretreated group when compared to the ratio from saline treated controls. Furthermore, neither naloxone (10 mg/kg ip, 15 mins before) nor naltrexone (3 mg/kg ip, 15 mins before) pretreatment affected the LD50 of cocaine. When tested 0.5, 1, 2, 4, 8 and 24 hrs after cocaine administration, sublethal dose of cocaine (80 mg/kg ip) injection resulted in significant increase in the plasma lactate dehydrogenase (LDH) levels. Buprenorphine pretreatment significantly attenuated cocaine-induced release of LDH. These results suggest that buprenorphine could be of potential advantage over naloxone in the management of cocaine and heroin ("speed ball") toxicity and in studies on the pharmacotherapy of cocaine-induced toxicity, LDH levels may be used as a biochemical marker to assess the protective effects of drugs.

Analysis of Variance↗
PubMed1991

Intracerebroventricular administration of kappa-agonists induces convulsions in mice.

Intracerebroventricular (ICV) administration of kappa-agonists (PD 117302, U-50488H and U-69593) induced convulsions in a dose-related manner in mice. The dose at which 50% of animals convulsed (CD50) was in nmol ranges for all opioids. Among the opioids used, PD 117302 was the most potent convulsant. ICV administration of either vehicle alone or U-53445E, a non-kappa-opioid (+) enantiomer of U-50488H did not induce convulsions. The convulsive response of kappa-agonists was differentially susceptible for antagonism by naloxone and/or MR 2266. Collectively, these findings support the view that convulsions induced by kappa-agonists in mice involve stereospecific opioid receptor mechanisms. Furthermore, the convulsant effect of kappa-agonists could not be modified by pretreatment with MK-801, ketamine, muscimol or baclofen. It is concluded that kappa-opioid but not NMDA or GABA receptor mechanisms are involved in convulsions induced by kappa-agonists. These results are the first experimental evidence implicating stereospecific kappa-receptor mechanisms in opioid-induced convulsions in mice.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1991

Anatomical basis for the clinical application of the arterial supply of musculus pectoralis major.

The pattern of arterial supply to the various parts (clavicular, sternocostal and aponeurotic) of the pectoralis major muscle was studied in 7 cadaver dissections and 10 angiograms by injecting a radio-opaque substance. Three main arteries supplied the muscle, i.e. the pectoral branch of the thoracoacromial trunk (TAT-PB), the lateral thoracic artery and the perorating branch of the internal thoracic artery, supported by other branches of the TAT and the superior thoracic artery. It is observed that the TAT-PB, a chief vascular pedicle, anastomoses freely with other arteries and supplies most parts of the muscle. The present study is mainly focussed on the exclusion of the chief vascular pedicle of muscle to eliminate the confusion of previous studies and prevent the unnecessary hindrance and complications of the muscle flap.

Humans↗
PubMed1990

[Polyunsaturated fatty acid preparations available on the Danish market. Composition and oxidative stability].

The emerging interest in essential polyunsaturated fatty acids has resulted in a number of products available in the Danish market. These products contain essential fatty acid oils rich in n-6 and n-3 fatty acids. The quality of these products plays a major role in planning prophylactic and clinical studies. This investigation therefore illustrates the quality and the contents of undesirable oxygenated compounds--peroxides and polymeric/oxidative components. Intake of these undesirable substances can theoretically contribute to the development of cancer. It is therefore of utmost importance to be aware of the quality of the product especially when relatively large doses are employed for a considerable period. Our results show that the oxidation values of the fish oil products are much higher than vegetable oils. Furthermore we observed higher amounts of polymerised/oxidised components in Pikasol although the peroxide value was relatively low. Okholm's fish oil and cod liver oil contain higher amounts of undesirable gadoleic and cetoleic acids. A quality control from the authorities is desirable as the consumer has only the producer's/importer's "assurances" to rely on and these are not always in accordance with the real facts.

Denmark↗
PubMed1990

Venoruton as a radioprotector: a haematological assessment.

Efficacy of Venoruton--O-(hydroxyethyl) Rutoside--as a radioprotector has been tested on haematological profile of rats which were subjected to whole body radiation (500 rads). The results show radiation induced lesions in respect of total (TLC) and differential leukocyte counts (DLC)/and haemoglobin are significantly lessened when Venoruton was administered prior to radiation exposure.

Animals↗
PubMed1989

Differential diagnosis of subungual melanoma from a surgical point of view.

Subungual lesion referred to a surgical unit over a 17-year period have been reviewed to assess problems of differential diagnosis and management of suspected subungual melanoma. Such lesions are uncommon, even in a unit with interest in melanoma. Only four melanomas were seen for primary treatment, and eight in all, during the period. We describe the clinical features of other subungual lesions seen in surgical patients which might help in their differentiation from melanoma. Differential diagnosis and a management policy to achieve early diagnosis are discussed in the light of data from this series and study of the relevant literature.

Aged↗
PubMed1989

Analysis of seed oils containing cyclopentenyl fatty acids by combined chromatographic procedures.

The fatty acids of seed oils of the Flacourtiaceae, Hydnocarpus anthelmintica, Caloncoba echinata and Taraktogenus kurzii, have been examined by a combination of capillary gas chromatography, silver ion high performance liquid chromatography and gas chromatography-mass spectrometry. In addition to the common range of cyclopentenyl fatty acids found in such oils, 13-cyclopent-2-enyltridec-4-enoic acid was a major component of H. anthelmintica and was identified by mass spectrometry as its picolinyl ester and dimethyldisulphide adduct. It has not previously been found in nature. In the other seed oils, the isolated double bond in the corresponding fatty acid was in position 6, as expected. Similarly, cis-4-hexadecenoic acid and C16 and C18 cyclopentyl fatty acids were identified for the first time in H. anthelmintica. Iso- and anteiso-methylbranched fatty acids were present in trace amounts.

Chromatography, High Pressure Liquid↗
PubMed1989

Theophylline pharmacokinetics in well-nourished and malnourished asthmatic children.

The influence of age, sex and nutritional status on theophylline pharmacokinetics was studied in stable asthmatic children. Theophylline was given at a dose of 6 mg/kg orally on an empty stomach and the pharmacokinetic parameters were calculated from the estimated plasma concentration of theophylline. No significant difference in the elimination half-life (t1/2), volume of distribution (Vd), clearance (cl) and area under the time plasma curve (AUC) could be observed between the three pediatric age groups. Also, there was no influence of sex and nutritional status on the pharmacokinetic parameters. The notable observation was a 5-fold interindividual difference in the peak plasma concentration (Cmax) after a single dose.

Adolescent↗