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Biomedical subjects

A Gupta

Publications and source records attributed to A Gupta.

At least 1,027 records · Page 57Linked to original sources
PubMedDate not supplied

Anatomical and functional differentiation of glutamatergic synaptic innervation in the neocortex.

Pyramidal neurons are the principal neurons of the neocortex and their excitatory impact on other pyramidal neurons and interneurons is central to neocortical dynamics. A fundamental principal that has emerged which governs pyramidal neuron excitation of other neurons in the local circuitry of neocortical columns is differential anatomical and physiological properties of the synaptic innervation via the same axon depending on the type of neuron targeted. In this study we derive anatomical principles for divergent innervation of pyramidal neurons of the same type within the local microcircuit. We also review data providing circumstantial and direct evidence for differential synaptic transmission via the same axon from neocortical pyramidal neurons and derive some principles for differential synaptic innervation of pyramidal neurons of the same type, of pyramidal neurons and interneurons and of different types of interneurons. We conclude that differential anatomical and physiological differentiation is a fundamental property of glutamatergic axons of pyramidal neurons in the neocortex.

Animals↗
PubMedDate not supplied

Investigation of antibiotic prophylaxis usage for vascular and nonvascular interventional procedures.

PURPOSE: To investigate current antibiotic prophylactic usage for arteriography, angioplasty, vascular stent placement, transjugular intrahepatic portosystemic shunt placement (TIPS), tunneled-port placement, inferior vena cava (IVC) filter placement, biliary drainage, genitourinary drainage, abdominal drainage, and enteral tube placement with an aim to better clarify indications and regimens for prophylaxis. METHODS: A questionnaire regarding antibiotic prophylactic usage was sent to 2,039 members of the Society of Cardiovascular and Interventional Radiology (SCVIR). There were 401 respondents. Replies were evaluated for frequency and indications of prophylaxis, specific prophylaxis used, and clarity of indications for prophylaxis. RESULTS: A majority of responders never used prophylaxis for arteriography, angioplasty, vascular stent placement, IVC filter placement, abdominal drainage, and enteral tube placement. Infective complication rates from nonusage ranged between 1% and 15%. Approximately 45% always used prophylaxis for tunneled-port placement and TIPS with a 13%-16% infective complication rate among nonusers. In contrast, a majority of responders always used prophylaxis for biliary and genitourinary drainage, with a 40%-58% infective complication rate in nonusers. More than 70% of responders believed that the indications for prophylaxis were not clear for arteriography, angioplasty, vascular stent placement, tunneled-port placement, TIPS, IVC filter placement, and enteral tube placement, and in contrast, that the indications for prophylaxis for biliary and genitourinary drainage were clear. Fifty-one percent of responders believed that indications for prophylaxis for abdominal drainage were clear. CONCLUSIONS: Indications for antibiotic prophylaxis are not clear to interventionalists for a large number of vascular and nonvascular interventional procedures. Prophylaxis appears unnecessary for routine arteriography, angioplasty, IVC filter placement, vascular stent placement, or enterostomy tube placement. Antibiotic prophylaxis is warranted for TIPS and tunneled-port placement. Conversely, indications for antibiotic prophylaxis are clear to interventionalists for biliary and genitourinary drainage procedures. Routine prophylaxis remains warranted for both.

Antibiotic Prophylaxis↗
PubMedDate not supplied

Two cases of cauda equina syndrome following spinal-epidural anesthesia.

BACKGROUND AND OBJECTIVES: Cauda equina syndrome (CES) is a well-known complication of spinal and epidural anesthesia. Previous reports have implicated lidocaine, chloroprocaine, and procaine in its etiology, but not bupivacaine. METHODS: A 63-year-old man underwent transurethral resection of the prostrate for which he received bupivacaine with glucose intrathecally. Postoperative, he had difficulty in urination and defecation, and magnetic resonance imaging revealed spinal stenosis at the L1-L2 level. The second patient was a 70-year-old woman who underwent hip replacement surgery using a combined spinal-epidural technique. Postoperative, after 42 hours, when the epidural infusion of bupivacaine was stopped, the patient had difficulty in urination and defecation. No anatomical abnormality was found on magnetic resonance imaging. RESULTS: The two patients developed cauda equina syndrome following bupivacaine with glucose injected spinally, and bupivacaine without glucose injected in a combined spinal-epidural technique. CONCLUSIONS: This case report describes two cases of CES following the use of bupivacaine. The first patient had spinal stenosis which could explain this complication; however the explanation for CES in the second patient is uncertain and consequently speculative. We have discussed the possible contributing factors but believe that the etiology of CES in the second patient remains unknown.

Aged↗
PubMedDate not supplied

Postoperative pain following knee arthroscopy: the effects of intra-articular ketorolac and/or morphine.

BACKGROUND AND OBJECTIVES: Morphine and nonsteroidal antiinflammatory drugs (NSAID) have been found to be effective in relieving postoperative pain. The goal of this study was to determine whether ketorolac alone or in combination with morphine provides superior pain relief following arthroscopy performed with local anesthesia (LA). METHODS: This was a randomized, double-blind, prospective, study in 100 healthy patients from 15 to 60 years of age. Knee arthroscopy was performed with LA using 40 mL prilocaine (5 mg/mL) with adrenaline (4 microg/mL). At the end of the operation, a catheter was inserted intra-articularly, and one of the following solutions diluted to a total volume of 40 mL was injected: group P (40 mL normal saline), group M (3 mg morphine), group K30 (30 mg ketorolac), group K60 (60 mg ketorolac), and group KM (3 mg morphine + 30 mg ketorolac). Visual analog scale (VAS) pain scores (0-100 mm) were measured preoperative and at 30, 60, 90, 120 minutes postoperative and thereafter 4, 8, 24, and 48 hours at rest and on movement of the knee. The total number of distalgesic tablets (325 mg paracetamol + 32.5 mg dextropropoxyphene) consumed during the 48 hours postoperative was recorded. RESULTS: Significant differences in VAS pain scores were seen between group P and group KM at 4, 8, and 24 hours (P < .05) and between group M and group KM at 4, 8, 24, and 48 hours (P < .01) after the operation at rest. During mobilization of the knee, a significant difference in VAS pain score was found between group P and group KM at 8, 24, and 48 hours (P < .05) and between group P and group K60 at 24 and 48 hours (P < .05). The total consumption of distalgesic tablets did not differ among the groups. CONCLUSIONS: The combination of 3 mg morphine plus 30 mg ketorolac provided significantly better analgesia than either placebo alone or morphine alone. This result could be a synergistic effect.

Adolescent↗
PubMedDate not supplied

Mixed-ligand technetium(III) complexes with tetradendate/monodendate NS(3)/isocyanide coordination: a new nonpolar technetium chelate system for the design of neutral and lipophilic complexes stable in vivo.

Starting from the tripodal ligand 2,2',2' '-nitrilotris(ethanethiol) (NS(3)) and isocyanides (CNR) as co-ligands, neutral mixed-ligand technetium(III) complexes of the general formulation [Tc(NS(3))(CNR)] have been synthesized and characterized. The (99)Tc complexes can be( )()obtained by a two-step reduction/substitution procedure starting from [TcO(4)](-) via the phosphine-containing precursor complex [Tc(NS(3))(PMe(2)Ph)]. As shown by X-ray structural analyses, the complexes adopt a nearly ideal trigonal-bipyramidal geometry with the trigonal plane formed by the three thiolate sulfurs of the tripodal ligand. The central nitrogen atom of the chelate ligand and the monodendate isocyanides occupy the apical positions. The no-carrier-added preparation of the corresponding (99m)Tc complexes was performed by a one-step procedure starting from (99m)[TcO(4)](-) with stannous chloride as reducing agent. Biodistribution studies in the rat demonstrated for the nonpolar, lipophilic compounds a significant initial brain uptake. In vitro challenge experiments with glutathione clearly indicated that no transchelation reaction occurs. Furthermore, there were no indications for reoxidation of Tc(III) to Tc(V) species or pertechnetate. We propose this type of complexes as a useful tool in the design of lipophilic (99m)Tc or (186)Re/(188)Re radiopharmaceuticals.

Animals↗
PubMedDate not supplied

Chemical and biological characterization of technetium(I) and Rhenium(I) tricarbonyl complexes with dithioether ligands serving as linkers for coupling the Tc(CO)(3) and Re(CO)(3) moieties to biologically active molecules.

The organometallic precursor (NEt(4))(2)[ReBr(3)(CO)(3)] was reacted with bidendate dithioethers (L) of the general formula H(3)C-S-CH(2)CH(2)-S-R (R = -CH(2)CH(2)COOH, CH(2)-C&tbd1;CH) and R'-S-CH(2)CH(2)-S-R' (R' = CH(3)CH(2)-, CH(3)CH(2)-OH, and CH(2)COOH) in methanol to form stable rhenium(I) tricarbonyl complexes of the general composition [ReBr(CO)(3)L]. Under these conditions, the functional groups do not participate in the coordination. As a prototypic representative of this type of Re compounds, the propargylic group bearing complex [ReBr(CO(3))(H(3)C-S-CH(2)CH(2)-S-CH(2)C&tbd1;CH)] Re2 was studied by X-ray diffraction analysis. Its molecular structure exhibits a slightly distorted octahedron with facial coordination of the carbonyl ligands. The potentially tetradentate ligand HO-CH(2)CH(2)-S-CH(2)CH(2)-S-CH(2)CH(2)-OH was reacted with the trinitrato precursor [Re(NO(3))(3)(CO)(3)](2-) to yield a cationic complex [Re(CO)(3)(HO-CH(2)CH(2)-S-CH(2)CH(2)-S-CH(2)CH(2)-OH)]NO(3) Re8 which shows the coordination of one hydroxy group. Re8 has been characterized by correct elemental analysis, infrared spectroscopy, capillary electrophoresis, and X-ray diffraction analysis. Ligand exchange reaction of the carboxylic group bearing ligands H(3)C-S-CH(2)CH(2)-S-CH(2)CH(2)-COOH and HOOC-CH(2)-S-CH(2)CH(2)-S-CH(2)-COOH with (NEt(4))(2)[ReBr(3)(CO)(3)] in water and with equimolar amounts of NaOH led to complexes in which the bromide is replaced by the carboxylic group. The X-ray structure analysis of the complex [Re(CO)(3)(OOC-CH(2)-S-CH(2)CH(2)-S-CH(2)-COOH)] Re6 shows the second carboxylic group noncoordinated offering an ideal site for functionalization or coupling a biomolecule. The no-carrier-added preparation of the analogous (99m)Tc(I) carbonyl thioether complexes could be performed using the precursor fac-[(99m)Tc(H(2)O)(3)(CO)(3)](+), with yields up to 90%. The behavior of the chlorine containing (99m)Tc complex [(99m)TcCl(CO)(3)(CH(3)CH(2)-S-CH(2)CH(2)-S-CH(2)CH(3))] Tc1 in aqueous solution at physiological pH value was investigated. In saline, the chromatographically separated compound was stable for at least 120 min. However, in chloride-free aqueous solution, a water-coordinated cationic species Tc1a of the proposed composition [(99m)Tc(H(2)O)(CO)(3)(CH(3)CH(2)-S-CH(2)CH(2)-S-CH(2)CH(3))](+) occurred. The cationic charge of the conversion product was confirmed by capillary electrophoresis. By the introduction of a carboxylic group into the thioether ligand as a third donor group, the conversion could be suppressed and thus the neutrality of the complex preserved. Biodistribution studies in the rat demonstrated for the neutral complexes [(99m)TcCl(CO)(3)(CH(3)CH(2)-S-CH(2)CH(2)-S-CH(2)CH(3))] Tc1 and [(99m)TcCl(CO)(3)(CH(2)-S-CH(2)CH(2)-S-CH(2)-C&tbd1;CH)] Tc2 a significant initial brain uptake (1.03 +/- 0.25% and 0.78 +/- 0.08% ID/organ at 5 min. p.i.). Challenge experiments with glutathione clearly indicated that no transchelation reaction occurs in vivo.

Animals↗
PubMedDate not supplied

The growth of malignant keratinocytes depends on signaling through the PGE(2) receptor EP1.

Recent discoveries shed light on the importance of prostaglandin (PG) production in the development of skin cancer. Work by Fischer et al. demonstrates that skin tumor promotion caused by ultraviolet B radiation can be decreased by up to 89% by blocking cyclooxygenase-2 (COX-2) with the drug Celecoxib. A similar study showed that Celecoxib can decrease new tumor formation by 44% in mice that already have tumors. These studies demonstrate the importance of COX-2 and PGs in the development of squamous cell carcinoma. We have explored growth signaling in a model of skin tumor progression. Because changes in PG production have been implicated in skin carcinogenesis, we examined this pathway. We found that malignant cell lines secrete more prostaglandin E(2) (PGE(2)) than the parental cells. We observed increased expression of COX-1 and -2. We also found that these cells express the PGE(2) receptors EP1 and EP4. When the cells are grown in the presence of indomethacin, the growth rate of the malignant cells is decreased. This effect can be reversed by addition of PGE(2) or an EP1 agonist to the medium. Thus, we have shown that skin tumor cells depend in part on PGE(2) signaling through the EP1 prostanoid receptor for their in vitro growth.

Animals↗
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Giant congenital melanocytic nevus with underlying hypoplasia of the subcutaneous fat.

A 17-week-old boy with a giant congenital melanocytic nevus (GCMN) of the left lower extremity was noted to have a reduction in circumference of the left lower extremity relative to the contralateral side. The skin overlying the GCMN was persistently warm when compared with the surrounding and contralateral skin. Comparative plain radiography, ultrasonography, and magnetic resonance imaging showed fat hypoplasia of the left lower extremity, with bone and muscle appearing unaffected. The possible role of cytokines produced by the nevus in fat hypoplasia in GCMN is discussed.

Adipose Tissue↗
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Recurrent diarrhea in children living in areas with high levels of nitrate in drinking water.

Given that there was documented evidence of an association between diarrhea and high nitrate ingestion, the authors examined drinking water nitrate concentration and its possible correlation(s) with methemoglobin levels, cytochrome b5 reductase activity, and recurrent diarrhea. In addition, the authors studied histopathological changes in the intestines of rabbits in an animal model. Five village areas were studied, and nitrate concentrations (expressed in mg of nitrate per liter of water) of 26, 45, 95, 220, and 459 existed in the respective villages. The study included 88 randomly selected children who were 8 yr of age or younger; they represented 10% of the total population of each of the areas. Detailed histories of recurrent diarrhea were noted, and medical examinations were conducted. Cytochrome b5 reductase activity and methemoglobin levels were estimated biochemically. Collected data were analyzed statistically with Microsoft Excel software. In addition, the authors exposed rabbits to various levels of nitrate, and histopathological changes of the stomach and intestine (small and large) were evaluated. There was a strong relationship between nitrate concentration and recurrent diarrhea; 80% of the recurrent diarrhea cases were explained by nitrate concentration alone. In the rabbit intestines, lymphocytic infiltration and hyperplasia characterized the submucosa as nitrate concentrations increased.

Acute Disease↗
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Skin diseases in children with HIV infection and their association with degree of immunosuppression.

Since the recognition of the acquired immunodeficiency syndrome (AIDS) in 1981, several dermatologic manifestations have been associated with the syndrome, including candidiasis, dermatophyte infection, molluscum contagiosum, herpes simplex and zoster, bacterial infection, and malignancy. Skin diseases have been observed in both the adult and the pediatric human immunodeficiency virus (HIV) infection in an academic hospital setting in relationship to the current CDC classification of pediatric HIV infection. The severity of dermatologic manifestations is correlated with the immune status of the patients. The latter was determined by T4 helper cell numbers and lymphoproliferative responses to mitogens and recall antigens. More severe T helper cell depletion was associated with a wider spectrum and increased severity of dermatologic manifestations.

Acquired Immunodeficiency Syndrome↗
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Chronic hepatitis C virus infection in renal transplant: treatment and outcome.

BACKGROUND: Chronic hepatitis C virus (HCV) infection is a common cause of liver disease in post-renal transplant period and causes poor patient and graft survival. We analyzed the effects of antiviral therapy using ribavirin monotherapy or ribavirin in combination with interferon (IFN)-alpha in our kidney transplant recipients with chronic hepatitis C. METHODS: Total of 14 patients received antiviral therapy, all of whom had stable graft function, raised aminotransferases and positive HCV viremia at the start of treatment. Eight patients received ribavirin alone for a period of six months to two yr, in doses of 400-800 mg daily. Five patients received IFN-alpha therapy for a period of two months to 1.5 yr, in doses of 1.5 million units daily or three million units thrice weekly with ribavirin. One patient received pegylated IFN 50 microg once weekly in combination with ribavirin. The response was seen in terms of biochemical and virological improvement at the end of study period. RESULTS: In patients treated with ribavirin alone (n = 8), mean alanine aminotransferase (ALT) levels before and after treatment were significantly different (198.4 +/- 147.6 and 104.8 +/- 66.5 IU/L respectively; p < 0.05). ALT levels normalized completely in three patients at the end of treatment, improved in three patients and deteriorated in two. Only in one of eight patients on ribavirin alone, HCV-RNA became negative after six months of treatment while in the rest (n = 7) HCV-RNA continued to be positive. In subjects on IFN plus ribavirin (n = 6), the mean ALT levels decreased significantly (from 280.2 +/- 114.9 IU/L at baseline to 71 +/- 49 IU/L at end of therapy; p < 0.05). Two patients had sustained remission (33.3%) on IFN plus ribavirin (persistently negative HCV-RNA), two patients relapsed after initial remission and in two patients treatment was stopped after two months because of graft dysfunction. Totally four patients developed graft dysfunction at some time during the course of IFN therapy (66.6%), but it was discontinued in only two (33.3%). All patients regained normal creatinine levels after discontinuation of IFN, although one patient developed chronic allograft nephropathy as shown by kidney biopsy. Four patients in IFN group developed leucopenia. Two patients developed severe anemia one of whom required blood transfusion and one developed severe flu-like syndrome requiring stoppage of therapy. CONCLUSION: Ribavirin monotherapy in renal transplant recipients with chronic hepatitis C infection results in good biochemical response but is not associated with virological clearance. IFN in combination with ribavirin is effective in two-thirds of patients after a minimum therapy of six months, but it is poorly tolerated, results in graft dysfunction in significant number of patients, and relapse can occur after stopping treatment.

Adult↗
PubMedDate not supplied

Composition of Pneumocystis carinii neutral lipids and identification of coenzyme Q10 as the major ubiquinone homolog.

The lipids of purified preparations of Pneumocystis carinii carinii freshly isolated from infected rats were analyzed and compared with those of whole lungs from normal and methylprednisolone-immunosuppressed uninfected rats. In this study, the neutral lipid fraction was examined in detail; the relative concentrations of individual classes making up this fraction were quantified. Of particular interest was the nature of the organism's ubiquinone (coenzyme Q, CoQ) fraction because atovaquone, a hydroxynaphtho-quinone (566C80) analog of ubiquinone, is efficacious in the treatment of P. carinii pneumonia. The ubiquinone concentration in both P. carinii and lung tissues was relatively low compared to that present in rat heart and liver tissues. Two homologs were identified in the organism: CoQ10 was the predominant homolog with lesser amounts of CoQ9 present. In contrast, the lungs of normal and immunosuppressed uninfected rats had CoQ9 and lesser amounts of CoQ8, but no detectable CoQ10. Furthermore, radiolabeled mevalonic acid was incorporated in vitro into the ubiquinone fraction of P. carinii indicating that the organism has the de novo branch of the isoprenoid biosynthetic pathway leading to polyprenyl formation. Hence, it was concluded that CoQ10 (if not both CoQ10 and CoQ9) in P. carinii was not scavenged from the host but was synthesized by the organism. Although lung tissues contained substantial free fatty acids, the organism was enriched in these lipids. The high concentration of free fatty acids and relatively low level of triglycerides in P. carinii suggest that fatty acids may represent major carbon sources for ATP production by the organism.

Animals↗
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Evaluation of ground water monitoring network by principal component analysis.

Principal component analysis is a data reduction technique used to identify the important components or factors that explain most of the variance of a system. This technique was extended to evaluating a ground water monitoring network where the variables are monitoring wells. The objective was to identify monitoring wells that are important in predicting the dynamic variation in potentiometric head at a location. The technique is demonstrated through an application to the monitoring network of the Bangkok area. Principal component analysis was carried out for all the monitoring wells of the aquifer, and a ranking scheme based on the frequency of occurrence of a particular well as principal well was developed. The decision maker with budget constraints can now opt to monitor principal wells which can adequately capture the potentiometric head variation in the aquifer. This was evaluated by comparing the observed potentiometric head distribution using data from all available wells and wells selected using the ranking scheme as a guideline.

Data Interpretation, Statistical↗
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Prenatal diagnosis in beta-thalassemia: an Indian experience.

OBJECTIVES: Thalassemia is the most common single gene disorder and is widely distributed in Asian Indians with an average prevalence rate of 4%, with a high prevalence among Sindhis, Punjabis, Gujratis and Bengalis. Prevention and control of beta-thalassemia disease require the accurate diagnosis of carriers and proper genetic counseling. METHOD: Prenatal diagnosis can be performed in the first or second trimester of pregnancy by DNA analysis using polymerase chain reaction. Since there are 17 mutations as well as rare ones causing beta-thalassemia in Asian Indians, the point mutation detection by reverse dot blot (RDB) allele-specific oligonucleotide hybridization for common mutations along with the amplification refractory mutation system (ARMS) technique was developed for prenatal diagnosis. Maternal contamination of fetal DNA was ruled out by the variable number of tandem repeat analysis using apolipoprotein B site. RESULTS: Using both techniques (RDB and ARMS) we were able to offer complete diagnosis in 53 pregnancies. On molecular analysis 23% were found to be normal, 48.0% were carriers, and 29.0% were affected with beta-thalassemia. Parents were counseled to continue the pregnancy when the fetuses were either normal or had traits whereas in the case of an affected fetus, the parents opted for termination of the pregnancy. CONCLUSION: Prenatal diagnosis of beta-thalassemia by the RDB or ARMS technique can prevent the birth of an affected child in developing countries in which beta-thalassemia is quite prevalent.

DNA Mutational Analysis↗
PubMedDate not supplied

Ultrasound-guided fine needle aspiration cytology of malignant gallbladder masses.

OBJECTIVE: To determine the accuracy and reliability of ultrasound (US)-guided fine needle aspiration cytology (FNAC) over blind aspiration in gallbladder masses. STUDY DESIGN: We performed FNAC in 107 cases of carcinoma of the gallbladder; blind aspiration was done in 71 patients (66.36%) and US-guided aspiration in 36 (33.64%). In cases where FNAC after the first aspiration showed the aspirate to be inflammatory, acellular (inconclusive) or suspicious for malignancy, FNAC was repeated under US guidance. Diagnosis was later confirmed by histopathology in all cases. RESULTS: After the first aspiration, gallbladder malignancy was confirmed in 77 (71.96%) cases. Of these 77 cases, 34 underwent US-guided aspiration, and the remaining 43 underwent blind aspiration. Cases with inflammatory or acellular (inconclusive) aspirates or that were suspicious for malignancy after the first aspiration underwent a second aspiration under ultrasonic guidance. On the second aspiration of 30 cases, 16 (53.33%) proved to be of adenocarcinoma, 7 (23.33%) were suspicious for malignancy, 5 (16.66%) were inflammatory, and 2 (6.66%) were acellular. Diagnosis was later confirmed by histopathology in all cases. US-guided FNAC had diagnostic accuracy of 95% as compared to 60% on blind aspiration. There was no major complication or needle tract recurrence of the disease. CONCLUSION: US-guided FNAC is safe, rapid, reliable, cost-effective and accurate in diagnosing gallbladder carcinoma.

Adenocarcinoma↗
PubMedDate not supplied

Bilateral cataract following lightning injury.

PURPOSE: To report a case of bilateral cataract with posterior vitreous detachment induced by lightning injury. METHODS: A case report of 30 year old man injured by lightning. RESULTS: The patient developed visually significant bilateral cataract after four years of the initial insult on the scalp. The exit wound was noted on the right foot. Fundus evaluation after cataract extraction revealed posterior vitreous detachment. CONCLUSIONS: Lightning can induce various ocular complications. Decrease in vision due to cataract is usually seen years after the initial lightning injury as the initial changes are in the mid-periphery and often missed in the acute setting. Posterior vitreous detachment induced by lightning can rarely lead to retinal tear formation and subsequently retinal detachment. The severity of entry and exit may not give a true picture of the internal organ damage.

Adult↗