Search PubMed⌕ Search

Biomedical subjects

M Khalil

Publications and source records attributed to M Khalil.

At least 37 records · Page 2Linked to original sources
PubMed2000

Basal cell adenocarcinoma of the lacrimal gland.

PURPOSE: Basal cell adenocarcinoma is a recently recognized entity among malignant tumors of the salivary glands. This entity has not received enough attention among ophthalmologists and ophthalmic pathologists. We recommend that basal cell adenocarcinoma be included in the differential diagnosis of lacrimal gland tumors. DESIGN: Case report. METHODS: In 1988 a lacrimal gland tumor was incompletely removed from the left orbit of a 36-year-old woman and diagnosed as "solid basaloid adenoid cystic carcinoma". Soon after, an exenteration of the orbit was performed. In 1998, upon review of the initial histopathology, the diagnosis of solid adenoid cystic carcinoma was changed to basal cell adenocarcinoma. RESULTS AND MAIN OUTCOME MEASURE: The pathologic findings included nests of basaloid cells with minimal atypia and incomplete palisading around the periphery. The cells were of two types. The first type were large, pale cells with round or oval nuclei, scanty cytoplasm, and ill-defined borders. The other type were smaller cells with hyperchromatic nuclei situated mainly near the periphery of the nests. There was no necrosis or perineural invasion. Mitotic figures were present. Cysts within the nests showed Alcian blue negative contents. Immunohistochemistry showed a positive reaction to cytokeratin and a negative reaction with smooth muscle actin (SMA). CONCLUSIONS: The Alcian blue negative stain, the negative reaction to SMA, and the fact that the patient is still alive 10 years after exenteration favored the diagnosis of basal cell adenocarcinoma. It is essential to differentiate a basal cell adenocarcinoma of the lacrimal gland from the solid basaloid type of adenoid cystic carcinoma, because the former has a better prognosis. Patients with basal cell adenocarcinomas of the lacrimal gland should be closely monitored for local recurrences because this tumor has the tendency to show perineural invasion.

Adenocarcinoma↗
PubMed2000

Simultaneous subconjunctival and subscleral mitomycin-C application in trabeculectomy.

OBJECTIVE: To establish the efficacy and safety of simultaneous subconjunctival and subscleral application of mitomycin-C in trabeculectomy. DESIGN: A prospective, randomized study. PARTICIPANTS: Sixty-eight patients (68 eyes) with refractory glaucomas were included in the study. INTERVENTION: Eyes were randomly assigned to receive intraoperative mitomycin-C (0.3 mg/ml) applied under the conjunctival flap (group 1), scleral flap (group 2), or under both flaps (group 3). MAIN OUTCOME MEASURES: Mean intraocular pressure (IOP), postoperative medications, visual acuity, filtering bleb appearance, and complications. RESULTS: There was a significant difference in IOP at 6, 9, and 12 months after surgery among the three groups (P = 0.021, 0.026, and 0.033, respectively ANOVA). At 12 months, the mean IOP in group 3 was 9.8+/-3.7 mm Hg compared with 13.4+/-5.5 mm Hg in group 2. (P = 0.015) and 12.4+/-4.4 mm Hg in group 1 (P = 0.039). Success rate (21 mm Hg or less), number of antiglaucoma medications, and complications showed no statistical significant difference between the three groups at each postoperative visit. CONCLUSIONS: Mitomycin-C applied under the scleral flap may have an additional beneficial effect when combined with simultaneous subconjunctival exposure.

Adult↗
PubMed2000

Uterine EMG analysis: a dynamic approach for change detection and classification.

Toward the goal of detecting preterm birth by characterizing events in the uterine electromyogram (EMG), we propose a method of detection and classification of events in this signal. Uterine EMG is considered as a nonstationary signal and our approach consists of assuming piecewise stationarity and using a dynamic change detector with no a priori knowledge of the parameters of the hypotheses on the process state to be detected. The detection approach is based on the dynamic cumulative sum (DCS) of the local generalized likelihood ratios associated with a multiscale decomposition using wavelet transform. This combination of DCS and multiscale decomposition was shown to be very efficient for detection of both frequency and energy changes. An unsupervised classification based on the comparison between variance-covariance matrices computed from selected scales of the decomposition was implemented after detection. Finally a class labeling based on neural networks was developed. This algorithm of detection-classification-labeling gives satisfactory results on uterine EMG: in most cases more than 80% of the events are correctly detected and classified whatever the term of gestation.

Algorithms↗
PubMed2000

Three dimensional culture upregulates extracellular matrix protein expression in human liver cell lines--a step towards mimicking the liver in vivo?

Extracellular matrix (ECM) in the liver affects the phenotype of both hepatocytes and non-parenchymal cells. To be able to mimic in vivo liver function for extracorporeal hepatic support using human cell lines, a necessary step is to upregulate the function normally seen in monolayer culture. 3-D spheroid colonies were formed by culturing single HepG2 cells encapsulated in alginate beads. ECM expression in these cultures was compared to monolayer Hep G2 cultures. The following ECM proteins were detected immunohistochemically:- collagens 1, III, V and VI, the glycoproteins fibronectin, tenascin and vitronectin, and the basement membrane protein laminin. In 3-D cultures, all proteins except tenascin were strongly expressed, as compared with weak or undetectable expression in monolayer cultures, even with 10-fold increases in the antibody concentration used. In conclusion, we have demonstrated that the 3-D environment created by alginate encapsulation of cell lines leads to cell behaviour mimicking that in vivo.

Cells, Cultured↗
PubMed1999

Laparoscopic extraperitoneal inguinal hernia repair. A safe approach based on the understanding of rectus sheath anatomy.

We have devised a reproducible approach to the preperitoneal space for laparoscopic repair of inguinal hernias that is based on an understanding of the abdominal wall anatomy. Laparoscopic totally extraperitoneal herniorrhaphy was performed on 99 hernias in 90 patients at the Los Angeles County-University of Southern California Medical Center, using a standardized approach to the preperitoneal space. Operative times, morbidity, and recurrence rates were recorded prospectively. The median operative time was 37 min (range, 28-60) for unilateral hernias and 46 min (range, 35-73) for bilateral hernias. There were no conversions to open repair, and there was only one conversion to a laparoscopic transabdominal approach. Complications were limited to urinary retention in two patients, pneumoscrotum in one patient, and postoperative pain requiring a large dose of analgesics in one patient. All patients were discharged within 23 h. There were no recurrences or neuralgias on follow-up at 2 years. A standardized approach to the preperitoneal space based on a thorough understanding of the abdominal wall anatomy is essential to a satisfactory outcome in hernia repair.

Adolescent↗
PubMed1999

Role of interferon-alpha in the treatment of primary glomerulonephritis.

Interferon-alpha (IFN-alpha) is a naturally occurring cytokine. It was the first cytokine used with clinical benefit in the treatment of viral hepatitis and malignancies. Patients with viral hepatitis B or C may have complications with glomerulonephritis (GN). Improvement in proteinuria with or without clearing of viral markers after IFN-alpha therapy has been reported. This encouraged us to offer IFN-alpha therapy to four patients with GN. These patients refused treatment with steroids and/or cyclophosphamide because of concerns about side effects. One patient with membranous GN and two patients with mesangial GN (MesGN) had a remission of nephrotic syndrome. In one patient with type II diabetes and MesGN, renal insufficiency and proteinuria did not subside; however, renal function remained stable. The mechanism of action of IFN-alpha is discussed, with its possible role in the treatment of primary GN.

Adult↗
PubMed1999

One-site versus 2-site phacotrabeculectomy: a randomized study.

PURPOSE: To compare 1-site and 2-site combined phacoemulsification with foldable intraocular lens (IOL) implantation and trabeculectomy. SETTING: El-Maghraby Eye Hospital, Jeddah, Saudi Arabia. METHODS: Seventy-six eyes with coexisting cataract and glaucoma were randomly assigned to have a mitomycin-C trabeculectomy in a superior quadrant combined with phacoemulsification and foldable IOL implantation through the same incision (1-site group) or a separate, temporal, clear corneal incision (2-site group). Postoperative evaluation included visual acuity, intraocular pressure (IOP), bleb assessment, and number of antiglaucoma medications. Follow-up ranged from 12 to 18 months. RESULTS: Mean preoperative IOP was 28.1 mm Hg +/- 7.1 (SD) in the 2-site group and 26.2 +/- 6.5 mm Hg in the 1-site group. At 6 months postoperatively, mean IOP was 16.9 +/- 4.3 and 16.8 +/- 3.8 mm Hg, respectively (P = .9) and at 12 months, 17.6 +/- 3.3 and 19.1 +/- 3.1 mm Hg, respectively (P = .044). Twenty-three of 39 eyes (59%) in the 2-site group and 14 of 37 (38%) in the 1-site group had clinically apparent filtering blebs at 12 months (P = .065). Postoperative astigmatic change and complications were comparable. CONCLUSION: Mitomycin-C trabeculectomy superiorly combined with separate temporal clear corneal phacoemulsification provided 1 year IOP control comparable to that with single-incision (1-site) combined cataract and glaucoma surgery.

Adult↗
PubMed1999

Ropivacaine 0.25% compared with bupivacaine 0.25% by the caudal route.

We compared in a randomized double-blind study, the postoperative analgesia and degree of motor block produced by the new local anaesthetic ropivacaine, with bupivacaine, for caudal anaesthesia in children. Eighty children, 2-5-years-old, ASA I, received one of two local anaesthetics; either ropivacaine 0.25% (1.0 ml x kg(-1)) or bupivacaine 0.25% (1.0 ml x kg(-1)). They were sedated with a continuous infusion of propofol (200 microg x kg(-1) min(-1). The lungs were ventilated with a mixture of 50% nitrous oxide with oxygen. 60 min after local anaesthetic injection, and every 60 min, the extent of the motor block in the recovery room was scored as 1-3, according to a modified Bromage scale. Adverse events and the time to the first analgesic requirement were reported. Patients in the two groups did not differ with respect to age, weight and height. There were no differences in heart rate and arterial pressure between the two groups(P>0.05). No adverse events were observed. The ropivacaine group showed a shorter duration of motor block than the bupivacaine group (P<0.05). The first postoperative analgesic requirement was a mean (sd) of 5 h+/-4.32 after the operation in the ropivacaine group and 5 h+/-3.81 for the bupivacaine group. These findings suggest that caudal anaesthesia with ropivacaine 0.25% in paediatric patients can be effective, with less motor blockade in the postoperative period.

Amides↗
PubMed1998

The augmentation of melanocytic nevi in guinea pigs by solar-simulated light: an animal model for human melanocytic nevi.

Strong epidemiological evidence confirms the role of sunlight in human melanoma induction. Furthermore, the frequency of melanocytic nevi is a good indicator of future development of melanoma and a short-term marker of adverse reactions to melanoma-inducing sun exposure in humans. Thus, the aim of this study was to develop and define an animal model for sunlight-induced nevi that can be used as a surrogate model for sunlight-induced melanoma. Five treatment groups of 30-40 Hartley albino guinea pigs/group were treated with topical 7,12-dimethylbenzanthracene at a dose range of 6-240 mg on the dorsum of the skin. At week 20, half of the animals in each group were given a 12-month regimen of minimal erythemal solar-simulated light, 3 times/week, increased weekly to maintain erythema. These regimes induced epidermally derived pigmented melanocytic nevi clinically and histologically similar to human nevi (junctional, compound, and dermal). S100 and HMB45 staining was also consistent with the patterns seen in human nevi. In contrast to the high-dose 7,12-dimethylbenzanthracene-treated animals (60 and 240 mg), where solar-simulated light had no effect on nevi multiplicity, those groups treated with low doses (24, 12, and 6 mg) had a significant increase in nevi multiplicity after 12 months of solar-simulated light treatment (24 mg, 0.5 nevi/animal unirradiated versus 1.4 nevi/animal irradiated, P = 0.03; 12 mg, 0.2 unirradiated versus 1.2 irradiated, P = 0.02; 6 mg, 0 unirradiated versus 1.9 irradiated, P = 0.008). UVB-induced minimal erythemal dose was unaltered after exposure to photoreactivating light, consistent with the observation of others that placental mammals lack the DNA photolyase responsible for strong photoreactivation seen in nonplacental mammals and lower metazoans. Thus, our guinea pig model has some of the essential elements required to be a robust animal model for human nevi and a surrogate model for melanoma. These nevi are augmented by solar-simulated light, are histologically similar, occupy the same level within the skin, have the same natural history as human nevi, and are produced in an animal lacking strong photoreactivation. These features are not found in any previously described small laboratory animal model.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1998

MOCA and some proposed substitutes (Cyanacure, Conacure, Polacure 740M and Ethacure 300) as two-stage skin carcinogens in HRA/Skh hairless mice.

4,4'-Methylenebis(2-chlororaniline) (MOCA) is a suspect human carcinogen that has wide use as an industrial compound. Occupationally, exposure may occur through inhalation and ingestion, but skin absorption is the main route by which this compound gains entry into the body. Because of the justified concern about the continued use of MOCA, a number of substitutes have been proposed, including 1,2-bis(2-aminophenylthio)ethane (Cyanacure), Conacure, trimethylene glycol di-p-aminobenzoate (Polacure 740M) and 3,5-dimethylthio-2,4-toluenediamine/3,5-dimethylthio-2,6-tol uenediamine (Ethacure 300). There is very little information available about these substances, but they share the property of belonging to the same class (aromatic amines) as MOCA. Furthermore, at least two (Ethacure 300 and Cyanacure) are mutagenic in Salmonella. This study was undertaken to investigate if MOCA and substitutes, Polacure 740M, Ethacure 300, Cyanacure and Conacure have the potential to cause papillomas in a two stage initiation/promotion protocol in HRA/Skh hairless mice. When a maximum dose of 100 mg of substance was applied to the dorsal skin of these mice, Ethacure 300 and Cyanacure were markedly toxic. All of the compounds had little or no effect on skin tumor initiating activity following 12-O-tetradecanoylphorbol-13-acetate (TPA) promotion. One experiment with MOCA suggested that, at lower and less toxic dose, this substance may have promotional activity. Therefore, caution should still be exercised when using these compounds and it cannot be excluded that they may be active in other strains of mice or other laboratory animal species.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1998

Treatment of total colonic aganglionosis by a modified Martin procedure--a preliminary report.

We report on a case of total colonic aganglionosis successfully treated by a modified Martin procedure under the specific environmental circumstances of a developing country. The single-approach procedure comprises a preservation of the ileocaecal valve and a long ileum patch for the remaining colon and rectum after left hemicolectomy with the advantage of restitution of normal stool habits due to enhanced absorption function of the remaining colon.

Colectomy↗
PubMed1998

Regulation of yeast glycogen metabolism and sporulation by Glc7p protein phosphatase.

Glc7p is an essential serine/threonine type 1 protein phosphatase (PP1) from the yeast Saccharomyces cerevisiae, which has a role in many processes including cell cycle progression, sporulation, glycogen accumulation, translation initiation, and glucose repression. Two hallmarks of PP1 enzymes are very high amino acid sequence conservation and association of the catalytic subunit with a variety of noncatalytic, regulatory subunits. We tested the hypothesis that PP1 sequence conservation was the result of each PP1 residue playing a role in multiple intermolecular interactions. Analysis of 24 glc7 mutants, isolated primarily by their glycogen accumulation traits, revealed that every mutated Glc7p residue altered many noncatalytic subunit affinities and conferred unselected sporulation traits to various degrees. Furthermore, quantitative analysis showed that Glc7p affinity for the glycogen-binding noncatalytic subunit Gac1p was not the only parameter that determines the glycogen accumulation by a glc7 mutant. Sds22p is one Glc7p noncatalytic subunit that is essential for mitotic growth. Surprisingly, several mutant Glc7p proteins had undetectable affinity for Sds22p, yet grew apparently normally. The characterization of glc7 diploid sporulation revealed that Glc7p has at least two meiotic roles. Premeiotic DNA synthesis was undetectable in glc7 mutants with the poorest sporulation. In the glc7 diploids examined, expression of the meiotic inducer IME1 was proportional to the glc7 diploid sporulation frequency. Moreover, IME1 hyperexpression could not suppress glc7 sporulation traits. The Glc7p/Gip1p holoenzyme may participate in completion of meiotic divisions or spore packaging because meiotic dyads predominate when some glc7 diploids sporulate.

Alleles↗
PubMed1997

Selective upregulation of cytokine receptor subchain and their intracellular signalling molecules after peripheral nerve injury.

Numerous studies have suggested that growth factors and cytokines play an important role in the survival of injured neurons and in neurite elongation. Therefore, intracellular signalling pathways activated by growth factors and cytokine receptors play an important role in neuronal survival or for the re-establishment of connection. Since the JAK (janus kinase)-STAT (signal transducers and activators of transcription) signal transduction pathway is known to play a major role in cytokine receptor signalling, we first examined regulation of JAK gene expression following peripheral nerve injury by in situ hybridization histochemistry. The rat hypoglossal nerve was axotomized unilaterally and the mRNA levels for JAK1, JAK2. JAK3 and TYK2 were examined in the hypoglossal nucleus at postoperative times ranging from 1 to 35 days. Among the JAK family members, JAK2 and JAK3 were substantially increased in injured hypoglossal motoneurons, whereas no significant increases were observed for JAK1 and TYK2. These changes were further confirmed by immunohistochemistry using antibodies specific to JAK2 and JAK3. In addition, we examined the JAK2 and JAK3 associated cytokine receptor components, IL-2R gamma and gp130, which are common to various cytokine receptors. Among these, gp130 immunostaining was upregulated after nerve injury. This was also confirmed by in situ hybridization. These results suggest that the injured neuron prepares the molecular machinery involved in certain cytokine receptor signalling pathways at an early phase of the regenerative process, accelerating for the neuron to respond to cytokines that may regulate survival and/or neurite elongation.

Animals↗
PubMed1996

Antioxidant survey to assess antagonism to redox stress using a prokaryotic and an eukaryotic system.

Using a prokaryote (Escherichia coli) and a metazoa-resembling eukaryote (Ochromonas danica), we surveyed antioxidants which might overcome redox stress imposed by menadione sodium bisulphite (MD) and buthionine sulphoximine (BSO). BSO oxidant stress was evident only in O. danica; MD oxidant stress was evident in both organisms. Glutathione, its precursors, e.g. cysteine, homocysteine, and 2-oxo-4-thiazolidine carboxylic acid, and red blood cells, emerged as prime antioxidants for relieving BSO and MD oxidant stress. BSO and MD oxidant activity and antioxidant-annulling effect in O. danica were judged comparable to those found in animal cells whereas the results E. coli were not entirely equivalent. The O. danica system emerged as a practical, rapid, and useful system for pinpointing oxidant stressors and antioxidants, and shows promise for studies with mammalian systems.

Antioxidants↗
PubMed1996

Holotranscobalamins in B12 and non B12 requiring prokaryotes and eukaryotes.

Transcobalamins, vitamin B12 binding proteins, deliver B12 to cell surface receptors which then permit B12 to cross cell membranes for metabolic use. There is little documentation concerning B12 binding proteins in bacteria and protists. We found that prokaryotes and eukaryotes requiring B12, as well as those protists synthesizing B12, also produce several transcobalamins for functionally transporting B12 similar to humans.

Animals↗