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Biomedical subjects

A Amin

Publications and source records attributed to A Amin.

At least 55 records · Page 3Linked to original sources
PubMed1997

Increased nitric oxide production accompanied by the up-regulation of inducible nitric oxide synthase in vascular endothelium from patients with systemic lupus erythematosus.

OBJECTIVE: To investigate whether systemic lupus erythematosus (SLE) is accompanied by increased serum nitrite levels, whether active compared with inactive disease is associated with greater nitric oxide (NO) production, and whether endothelial cells or keratinocytes serve as cellular sources of NO by virtue of their increased expression of either constitutive nitric oxide synthase (cNOS) or inducible NOS (iNOS). METHODS: Fifty-one serum samples (46 from patients with SLE) were analyzed for NO production by measuring nitrite levels in a calorimetric assay. Skin biopsy samples from 21 SLE patients and 11 healthy volunteers were evaluated immunohistochemically, using monoclonal antibodies, for endothelial cell and keratinocyte cNOS and iNOS expression. RESULTS: Serum nitrite levels were significantly elevated in the 46 patients with SLE (mean +/- SEM 37 +/- 6 microM/liter) compared with controls (15 +/- 7 microM/liter; P < 0.01), and were elevated in patients with active SLE compared with those with inactive disease (46 +/- 7 microM/liter versus 30 +/- 7 microM/liter; P < 0.01). Serum nitrite levels correlated with disease activity (r = 0.47, P = 0.04) and with levels of antibodies to double-stranded DNA (r = 0.35, P = 0.02). Endothelial cell expression of iNOS in SLE patients (mean +/- SEM score 1.5 +/- 0.2) was significantly greater compared with controls (0.6 +/- 0.2; P < 0.01), and higher in patients with active disease compared with those with inactive SLE (1.7 +/- 0.2 versus 1.2 +/- 0.2; P < 0.01). Keratinocyte expression of iNOS was also significantly elevated in SLE patients (0.9 +/- 0.1) compared with controls (0.4 +/- 0.1; P < 0.001). With regard to expression of cNOS, there were no differences between patients with active SLE, those with inactive SLE, and normal controls in either the vascular endothelium or the keratinocytes. CONCLUSION: NO production is increased in patients with SLE, and 2 potential sources of excessive NO are activated endothelial cells and keratinocytes via up-regulated iNOS.

Adult↗
PubMed1997

Transplantation of adenovirally transduced allogeneic chondrocytes into articular cartilage defects in vivo.

Gene transfer to chondrocytes followed by intra-articular transplantation may allow for functional modulation of chondrocyte biology and enhanced repair of damaged articular cartilage. We chose to examine the loss of chondrocytes transduced with a recombinant adenovirus containing the gene for Escherichia coli beta-galactosidase (Ad.RSVntlacZ), followed by transplantation into deep and shallow articular cartilage defects using New Zealand White rabbits as an animal model. A type I collagen matrix was used as a carrier for the growth of the transduced chondrocytes and to retain the cells within the surgically created articular defects. Histochemical analysis of matrices recovered from the animals 1, 3 and 10 days after implantation showed the continued loss of lacZ positive chondrocytes. The number of cells recovered from the matrices was also compared with the initial innoculum of transduced cells present within the matrices at the time of implantation. The greatest loss of transduced cells was observed in the first 24 h after implantation. The numbers of transduced cells present within the matrices were relatively constant between 1 and 3 days postimplantation, but had progressively declined by 10 days postimplantation. These results suggest that transduction of chondrocytes followed by intra-articular transplantation in this rabbit model may enable us to examine the biological effects of focal transgenic overexpression of proteins involved in cartilage homeostasis and repair.

Adenoviridae↗
PubMed1997

Arsenic on tap.

Explore the source record for details and available documents.

Asia↗
PubMed1996

Practitioner and student latex exposure and allergy.

Greater application of universal precautions has increased practitioner exposure to chemicals present in personal protective equipment. Of prime concern is the latex present in examination and surgical gloves. A survey concerning latex exposure, allergies, and handwashing was administered to three advanced classes of dental students and was sent to 300 private practitioners in Central Indiana. Results indicate that adverse skin reactions to latex start while in dental school. Problems due to latex gloves were reported by 18.6 percent of the students. Student handwashing materials and methods were adequate, except for inadequate washing time. Adverse skin reactions were reported by 24.1 percent of practitioners wearing latex gloves. Two handwashing problems were noted--inadequate washing time and the common use of water instead of an antimicrobial soap after glove removal. Both students and practitioners reported relatively high levels of personal and family histories of allergy to a variety of sources.

Adult↗
PubMed1995

Nitric oxide stimulates ADP ribosylation of actin in association with the inhibition of actin polymerization in human neutrophils.

In these studies we provide conclusive evidence that (beta/gamma) actin present in human neutrophils is a substrate for nitric oxide (NO)-dependent ADP ribosylation and that this modification is associated with the inhibition of actin polymerization. A 43-kDa substrate for NO-dependent ADP ribosylation was identified as actin by four methods: (1) comigration with the botulinum C2 toxin substrate by two-dimensional gel electrophoresis (pI 5.2), (2) identity between the peptide map generated by V8 protease digestion of the NO and botulinum C2 substrates, (3) immunoprecipitation with antiactin antibodies, and (4) the ability of NO to ADP ribosylate purified neutrophil G-actin in the presence of plasma membrane cofactors. Because the ADP ribosylation of actin by the botulinum C2 toxin is known to inhibit F-actin polymerization, we examined the effect of NO on actin assembly. Flow cytometry revealed that NO inhibited formyl-methionine-leucine-phenylalanine (fMLP)-dependent (30 s at 37 degrees C) F-actin formation (108 +/- 8 vs. 89 +/- 6 relative fluorescence units, P < .02). These results were confirmed by quantification of F-actin formation by gel scanning (10% sodium dodecyl sulfate gel, Coomassie, and densitometry): pretreatment of polymorphonuclear leukocytes with NO resulted in a reduction of fMLP-induced, cytoskeletal-associated F-actin, which was accompanied by an increase of Triton-soluble G-actin. NO also inhibited F-actin formation, as observed by means of rhodamine phalloidin staining of neutrophils adherent to a fibronectin-coated surface. This effect was accompanied by a dose-dependent inhibition of neutrophil adherence in NO-treated cells. The data indicate that NO inhibits cytoskeletal assembly and adherence in human neutrophils in association with the ADP ribosylation of actin.

Actins↗
PubMed1995

Carcinoma of the prostate--state at initial presentation.

In this retrospective study an attempt is made to document the stage at initial presentation of prostatic cancer. Of the 142 patients seen, 84% presented in an advanced stage and this explains why radical prostatectomies are rarely done in India. Hence efforts are required to screen the population for early diagnosis of the disease.

Humans↗
PubMed1994

Immunohistochemical localization of blood-retinal barrier breakdown sites associated with post-surgical macular oedema.

Post-surgical macular oedema results from blood-retinal barrier breakdown, but it is not accompanied by structural abnormalities in the retinal vessels or retinal pigmented epithelium. Previous studies, using horseradish peroxidase in a primate model, suggested that leakage occurs primarily through this epithelium. This study was conducted to localize sites of the barrier breakdown in humans following different types of intra-ocular surgery and to compare them with eyes affected with ocular inflammatory disease, ocular infection, and choroidal melanoma. Paraffin sections of eyes were immunohistochemically stained for albumin to localize extravascular albumin, which was graded in a masked study. With aphakia/pseudophakia, penetrating keratoplasty, ocular inflammatory disease, ocular infection, and choroidal melanoma, barrier breakdown occurred primarily at the inner blood-retinal barrier (retinal vasculature), but leakage also occurred at the outer barrier (retinal pigmented epithelium). After retinal re-attachment surgery, the inner and outer blood-retinal barriers were equally compromised. Vascular leakage in the optic nerve head coincided with barrier failure in these disorders. The widespread pattern of blood-retinal barrier compromise with leakage at multiple sites suggests that soluble mediators are likely to play a role in postsurgical macular oedema, ocular inflammatory disease, and choroidal melanoma.

Albumins↗
PubMed1994

Crohn's disease with unusual enterouterine fistula in pregnancy.

Pregnancy complicated by development of Crohn's disease is rare. The presentation of symptomatic Crohn's disease during pregnancy was initially described in 1946. Crohn's disease has been described in a number of atypical locations and with development of unusual fistulas. The cases associated with pregnancy have in common a clinical picture of (1) delay in diagnosis, (2) frequent premature delivery, (3) surgical intervention during pregnancy, and (4) high fetal and maternal morbidity and mortality. To our knowledge, this case is the first to describe the radiologic findings of an enterouterine fistula in a case of Crohn's disease beginning during pregnancy.

Adolescent↗
PubMed1993

Characterization of the in vitro reconstituted cyclin A or B1-dependent cdk2 and cdc2 kinase activities.

Human cyclins A and B1 were assembled with the cdk2 or cdc2 protein to reconstitute their respective kinase activities in vitro. Both cyclins complemented either cdk2 or cdc2, yielding kinase activities that supported the phosphorylation of histone H1. Activation of cdk2-catalyzed H1 kinase activity by cyclin A required a 10-min preincubation of the two components, whereas cdc2 kinase supported phosphate incorporation without a detectable time lag upon the addition of cyclin B1, suggesting a slower association rate of cdk2 with cyclin A compared with cdc2 and cyclin B1. Both cdk2 and cyclin A, as well as cdc2 and cyclin B1, formed stable complexes in the absence of ATP and substrate that could be isolated after glycerol gradient centrifugation. Incubation of the isolated complexes with ATP and histone H1 supported the phosphorylation of the substrate. Cyclin A-activated cdk2 or cdc2 phosphorylated p107, a pRB-related cellular protein, 10 times more effectively than the cyclin B1-complexed kinases. This was most likely due to a direct association of cyclin A with p107 (Ewen, M. E., Faha, B., Harlow, E., and Livingston, D. (1992) Science 255, 85-87; Faha, B., Ewen, M. E., Tsai, L.-H., Livingston, D., and Harlow, E. (1992) Science 255, 87-90). The reconstituted cdc2-cyclin B1 complex incorporated 4-5-fold more phosphate into the p34 subunit of the three-subunit (p70, p34, and p14) human single-stranded DNA-binding protein (also called RP-A), a DNA replication and DNA repair factor, than cdc2-cyclin A. No detectable phosphorylation of the p34 protein was observed with cdk2 complexed with either cyclin B1 or A. These data indicate that both cyclins as well as the catalytic subunits are important factors in controlling the rate of phosphorylation of a given substrate. The cyclin-activated cdc2 family kinases may target their cellular substrates through cyclin-mediated protein-protein interactions.

CDC2 Protein Kinase↗
PubMed1993

Pancreatic cystogastrostomy by combined upper endoscopy and percutaneous transgastric instrumentation.

Minimally invasive endoscopic and radiologic techniques have been reported for internal gastric drainage of pancreatic pseudocysts but these have significant technical limitations. A purely endoscopic approach to cystogastrostomy provides limited access for instrumentation and hemostasis. Radiologically-guided percutaneous techniques cannot regularly provide an adequately wide cystogastrostomy opening. Reported is a patient who had a pancreatic cystogastrostomy performed using a minimally invasive surgical approach combining upper endoscopy and percutaneous transgastric surgical instrumentation. The upper endoscope essentially served as a camera. A percutaneous endoscopic gastrostomy tube served as a port for inserting laparoscopic instruments into the stomach. The laparoscopic instruments were used to create a 1.5 cm cystogastrostomy opening similar in size to what could be created by an open abdominal approach. The laparoscopy instruments provided good tactile feedback and excellent hemostatic control. Avoiding an open abdominal procedure shortened postoperative recovery and reduced patient discomfort. Although the pseudocyst recurred once, the same procedure was performed again and there has not been a recurrence for 10 months. The authors conclude that this minimally invasive surgical procedure provides an excellent alternative approach for internal drainage of selected pancreatic pseudocysts.

Adult↗
PubMed1993

Blunt abdominal aortic trauma in children: case report.

Injuries to the abdominal aorta as a result of blunt trauma in children are extremely rare. We encountered one such injury and a review of the literature revealed seven additional cases. Lower extremity ischemia, abdominal bruit, or paraplegia may suggest that diagnosis at the time of injury. Delayed presentations are characterized by abdominal pain or a pulsatile mass, with or without bruit. A high index of suspicion with early aortography is indicated to diagnose blunt aortic trauma.

Abdominal Injuries↗
PubMed1992

The influence of surgery and anaesthesia on the pharmacokinetics of pethidine in the horse.

The plasma concentration of pethidine was measured in 16 horses, after its administration intravenously (i.v.) at a dose rate of 1 mg/kg bodyweight (bwt). In eight animals studied before surgery, the plasma levels of the drug decreased in a bi-exponential manner with a distributive half life of 3 mins and an elimination half life of 57.7 mins. Total body clearance was 17.7 ml/kg bwt/min. The remaining horses were investigated immediately after a period of anaesthesia and surgery and in these animals the drug exhibited smaller volumes of distribution (V1 cand Vdarea) and a significantly lower clearance rate of 12.8 ml/kg bwt/min in these animals. Correlation between the plasma concentration of pethidine and information published previously on the duration of action of the agent in the horses suggests that plasma levels of approximately 0.4 microgram/ml are required to produce analgesia in this species.

Analgesics, Opioid↗