Biomedical subjects
Publications and source records attributed to A Lam.
This is the first reported case where the diagnosis of hypertrophic pyloric stenosis (HPS) was entertained in the antenatal period and the neonate was followed up in the postnatal period on a prospective basis until the HPS became manifest.
Neonatal venous sinus thrombosis is a well-recognized, but infrequently diagnosed, cause of neonatal encephalopathy. Previous reports have tended to omit reference to the importance of maternal factors in predisposing the infant to this condition. This report, in which eight patients with neonatal venous sinus thrombosis are presented, will reveal a strong association between pre-eclampsia, prothrombotic disorders, and neonatal venous sinus thrombosis. Contrary to previously published reports, there is a high likelihood of neurodevelopmental residua after this condition.
The goal of this project was to evaluate the feasibility of co-composting of soybean residues and leaves and the effects of turning frequency on compost quality. Soybean residues were mixed with leaves and sawdust in 1:1:3 (w/w wet weight) for achieving a C/N ratio of about 30. Three heaps of about 4 m3 of compost mixtures were prepared receiving a turning frequency of daily (pile A), 3-day (pile B) and weekly (pile C) turning. Different turning frequencies did not significantly affect the changes in pH and volatile solids throughout the composting period. High turning frequency caused a lower electrical conductivity and NH4-N contents as well as a shorter duration of thermophilic phase, because of a high heat loss by evaporation and volatilization of ammonia in the pile. The highest C decomposition of 4% occurred in the pile with a 3-day turning period, which coincided with the higher-nitrogen content in this treatment. All treatments with different turning frequencies reached maturation at 63 days as indicated by the soluble organic carbon, soluble NH4-N, C/N ratio and cress seed germination index. However, increasing the aeration during composting period was beneficial in accelerating the maturation process. Taking into consideration less labour and lower operation costs as compared to daily turning, it can be suggested that a 3-day turning frequency would be more appropriate for reaching acceptable quality of compost and ease in operation.
STUDY OBJECTIVE: To compare laparosonic coagulating shears (LCS), which use ultrasonic energy, and unipolar diathermy scissors with respect to depth of tissue injury. DESIGN: Prospective observational study (Canadian Task Force classification I). SETTING: A reproduced surgical setting. SUBJECTS: An anesthetized sheep. INTERVENTION: We laparoscopically harvested uterine horn and bowel tissue. MEASUREMENTS AND MAIN RESULTS: Tissue was transected while hemostasis was maintained. Two pathologists examined tissue independently, and each was blinded as to the instrument used for harvesting. Clinical characteristics and tissue injury created by the instruments were compared. CONCLUSION: Subjectively, LCS appeared to produce less smoke plume than diathermy scissors. It also produced greater tissue damage than unipolar electrosurgery on settings of 35 W cut and 30 W coagulate.
Dysmenorrhea can be a severe and debilitating symptom in many women. Although most women may find adequate relief of symptoms from pharmacological approaches, there remain a few with resistant pain. Presacral neurectomy, although technically challenging, may be offered after other approaches are unsuccessful. The operation is now performed increasingly by the laparoscopic approach, which has revived this operation in some centers. The anatomy, technique, and indications as well as a review of the literature supporting this operation are reviewed. The potential complications of this operation are discussed also.
Deeply infiltrating endometriosis was described in the early part of the last century. Only recently, has there become a greater awareness and understanding of this form of endometriosis aided in part by advances in laparoscopic surgical technology in techniques. The clinical implications of the disease as well as diagnosis and current management are reviewed.
A retrospective audit of medical records was conducted for one surgeon (AL). All patients who underwent laparoscopic presacral neurectomy for severe midline dysmenorrhoea were identified. Details of the preoperative symptoms, clinical findings and operative records were studied. Improvement of dysmenorrhoea was assessed according to a pain scale. Twelve patients who had a laparoscopic presacral neurectomy performed were identified. Eight patients reported significant improvement of symptoms, with a further two reporting mild improvement. Two patients failed to show any improvement of symptoms. We believe that the role of laparoscopic presacral neurectomy should be limited to patients with severe midline dysmenorrhoea not responding to the medical therapy. It may be a supplementary procedure to laparoscopic resection of endometriosis or adhesiolysis.
Although macroscopic geometric architecture is an important determinant of bone strength, there is limited published information relating to the validation of the techniques used in its measurement. This study describes new techniques for assessing geometry at the midfemur using magnetic resonance imaging (MRI) and dual-energy X-ray absorptiometry (DXA) and examines both the repeatability and the accuracy of these and previously described DXA methods. Contiguous transverse MRI (Philips 1.5T) scans of the middle one-third femur were made in 13 subjects, 3 subjects with osteoporosis. Midpoint values for total width (TW), cortical width (CW), total cross-sectional area (TCSA), cortical cross-sectional area (CCSA), and volumes from reconstructed three-dimensional (3D) images (total volume [TV] and cortical volume [CVol]) were derived. Midpoint TW and CW also were determined using DXA (Lunar V3.6, lumbar software) by visual and automated edge detection analysis. Repeatability was assessed on scans made on two occasions and then analyzed twice by two independent observers (blinded), with intra- and interobserver repeatability expressed as the CV (CV +/- SD). Accuracy was examined by comparing MRI and DXA measurements of venison bone (and Perspex phantom for MRI), against "gold standard" measures made by vernier caliper (width), photographic image digitization (area) and water displacement (volume). Agreement between methods was analyzed using mean differences (MD +/- SD%). MRI CVs ranged from 0.5 +/- 0.5% (TV) to 3.1 +/- 3.1% (CW) for intraobserver and 0.55 +/- 0.5% (TV) to 3.6 +/- 3.6% (CW) for interobserver repeatability. DXA results ranged from 1.6 +/- 1.5% (TW) to 4.4 +/- 4.5% (CW) for intraobserver and 3.8 +/- 3.8% (TW) to 8.3 +/- 8.1% (CW) for interobserver variation. MRI accuracy was excellent for TV (3.3 +/- 6.4%), CVol (3.5 +/- 4.0%), TCSA (1.8 +/- 2.6%), and CCSA (1.6 +/- 4.2%) but not TW (4.1 +/- 1.4%) or CW (16.4 +/14.9%). DXA results were TW (6.8 +/- 2.7%) and CW (16.4 +/- 17.0%). MRI measures of geometric parameters of the midfemur are highly accurate and repeatable, even in osteoporosis. Both MRI and DXA techniques have limited value in determining cortical width. MRI may prove valuable in the assessment of surface-specific bone accrual and resorption responses to disease, therapy, and variations in mechanical loading.
Tumor necrosis (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF family of cytokines that promotes apoptosis. TRAIL induces apoptosis in a wide variety of tumor cells but not in normal cells. Oncogene Bcl-2 can protect cells from apoptosis induced by various stress stimuli. However, it is not clear whether Bcl-2 can regulate TRAIL-induced apoptosis. The objective of this study was to investigate whether Bcl-2 can regulate apoptosis induced by TRAIL. TRAIL initiates the activation of caspases, the loss of mitochondrial transmembrane potential (Delta psi(m)), and the redistribution of mitochondrial cytochrome c. TRAIL has no effect on Delta psi(m) and apoptosis in Jurkat cells deficient in either FADD or caspase-8, suggesting both FADD and caspase-8 are required for TRAIL signaling. Overexpression of Bcl-2 delays, but does not inhibit, TRAIL-induced Delta psi(m), cytochrome c release from mitochondria and apoptosis, whereas etoposide-induced apoptosis is blocked by Bcl-2. XIAP, cowpox virus CrmA and baculovirus p35 inhibits TRAIL-induced apoptosis. These data suggest that TRAIL can be used to kill Bcl-2 positive cells that can not be killed by other class of chemotherapeutic drugs.
PURPOSE: To assess short and medium term outcomes of cataract surgery with intraocular lens implantation in Senegalese children less than fifteen years. METHODS: From 1992 to 1997, 50 eyes of 40 children between the age of 5 months and 14 years, suffering from cataract were operated. Some of them were seen untill 2000. Twenty-seven cataracts were congenital, 19 were traumatic, 2 were from corticosteroid side effects, 1 after uveitis, and 1 had no determined cause. Thirty-one had manual extracapsular surgery and 19 ultrasound cataract surgery. They all have a standard single-piece PMMA intraocular lens of 21 to 22 diopters, 12.0-12.5mm long, under the ciliaris silcus (34 cases) or in the capsular bag (16). The results were noted in the first week, at one month, at 3 months, and after. RESULTS: Exudative reactions were frequent in the anterior chamber: 20% of the eyes had such reactions during the operation, especially when a manual extracapsular extraction was performed, and 34% soon after operation. The reactions were generally revealed with one month of survey. Corticosteroids used before and after surgery reduced inflammation disorders but seemed to speed up the onset of secondary cataract. Posterior capsule opacification was observed in the first week after surgery. It increased from 45% at 3 months to 74% at 1 year and 100% after 3 years. Intraocular cristal lens implants are well tolerated with limited complications. Fifty-seven percent of the operated eyes we observed after 3 years had 30/60 or better visual acuity. CONCLUSION: Despite fairly frequent inflammation and secondary cataract, posterior chamber lens implantation in children is well tolerated. This suggest that, as in adults, intraocular lens implant would be the best treatment for aphakia.
The use of cDNA microarrays has made it possible to simultaneously analyze gene expression for thousands of genes. Microarray technology was used to evaluate the expression of >4000 genes in a rat model of myocardial infarction. More than 200 genes were identified that showed differential expression in response to myocardial infarction. Gene expression changes were monitored from 2 to 16 weeks after infarction in 2 regions of the heart, the left ventricle free wall and interventricular septum. A novel clustering program was used to identify patterns of expression within this large set of data. Unique patterns were revealed within the transcriptional responses that illuminate changes in biological processes associated with myocardial infarction.
An in vitro-in vivo correlation (IVIVC) was established for an osmotic controlled-release dosage form by deconvolution using data from an immediate-release treatment as the characteristic response. The established IVIVC was evaluated internally (predicting data used to develop the IVIVC) and externally (predicting data not originally included in developing the IVIVC), and the application of the IVIVC in product development was demonstrated. The estimated in vivo dissolution profile compared favorably with the in vitro drug release profile. Good agreement was demonstrated between the estimated and observed cumulative drug release across the entire time course (level A correlation) with low (<10%) predictive error for both C(max) and AUC(infinity). External validation using lots not initially included in the model development compared very well with the observed in vivo profile, with mean prediction errors less than 10% for both C(max) and AUC(infinity). The proposed method demonstrates a schema for developing IVIVCs using data from biostudies routinely conducted during formulation development. The method should facilitate product optimization and can support setting in vitro dissolution specification.
Connective tissue growth factor (CTGF) is a cysteine-rich protein induced by transforming growth factor beta (TGF- beta) in connective tissue cells. CTGF can trigger many of the cellular processes underlying fibrosis, such as cell proliferation, adhesion, migration and the synthesis of extracellular matrix; however, its role in acute and chronic cardiac injury is not fully understood. Here, we show that TGF- beta is a specific inducer of CTGF expression in both cardiac fibroblasts and cardiac myocytes. The activity of a CTGF promoter-based reporter construct correlated with endogenous CTGF expression, suggesting that TGF- beta induces CTGF expression most likely by activating its promoter. Upregulation of CTGF coincided with an increase in fibronectin, collagen type I and plasminogen activator inhibitor-1 production. Forskolin, a stimulator of cyclic AMP, blocked TGF- beta induced CTGF expression and reduced the basal level of CTGF, whereas an inhibitor that blocks the MAP kinase signaling pathway (PD 98059) significantly enhanced TGF- beta induced CTGF expression. Furthermore, we found that both TGF- beta and CTGF mRNAs were significantly elevated in the left ventricles and septa of rat hearts 2-16 weeks following myocardial infarction. This correlated well with concomitant increases in fibronectin, and type I and type III collagen mRNA levels in these animal hearts. Significant upregulation of CTGF was also detected in human heart samples derived from patients diagnosed with cardiac ischemia. Based on these findings, we propose that CTGF is an important mediator of TGF- beta signaling in the heart and abnormal expression of this gene could be used as a diagnostic marker for cardiac fibrosis.
We employed cDNA microarrays representing 4000 distinct sequences to profile changes in gene expression in a rodent model of heart disease, namely, progression to heart failure after myocardial infarction. Differential gene expression in the left ventricle was examined at 4-week intervals over a 12-week period after coronary artery ligation in rats. Over this time course, insulin-like growth factor-binding protein-3 (IGFBP-3) was found to have a greater expression than in nondiseased tissues. We then employed quantitative real-time PCR to analyze gene expression in neonatal rat cardiac myocytes that had been treated with recombinantly expressed IGFBP-3 to examine a number of transcriptional responses designed to reflect the heart failure phenotype. The IGFBP-3 protein was shown to induce transcription of atrial natriuretic factor (ANF) and beta-myosin heavy chain (B-MHC). Analysis of conditioned media taken from IGFBP-3-treated cardiac myocyte cultures demonstrated an increase in ANF protein as well as in protein synthesis, as determined by metabolic incorporation of a radiolabeled amino acid. However, transcriptional changes of troponin-1, endothelin-1, or angiotensin-II by IGFBP-3 were not observed.
Herniation of omentum or bowel through laparoscopic incision sites is uncommon. Herniations through 5 mm ports sites are very rare, with less than a handful described in the literature. Undoubtedly however, with the increasing interest.
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In canine lower esophageal sphincter, myogenic constitutive nitric-oxide (NO) synthase (NOS) in plasma membrane limits tone by opening large conductance Ca(2+)-dependent K(+) channels (BK(Ca) channels) and hyperpolarizing the membrane. We examined whether K(V) channels were involved and whether NO from enteric nerves and from NO donors used the same mechanisms. With nerves inactive, 100 nM iberiotoxin, like N-nitro-L-arginine (L-NOARG), increased tone but less. 4-Aminopyridine (4-AP) at 5 mM behaved similarly. Tetraethyl ammonium (TEA) at 20 mM equaled the effect of L-NOARG and occluded any tone increase from any combination of these agents. More than iberiotoxin or 4-AP, TEA decreased relaxations in response to sodium nitroprusside (SNP) or 3-morpholino-sydnonimine (Sin-1) by approximately 50%. In whole-cell patch-clamp recordings, TEA and 4-AP reduced outward K(+) currents additively by >90% at depolarization of +90 mV. Thus, K(+) channels in addition to BK(Ca) channels are opened by myogenic NO, and exogenous NO had relaxing effects both related and unrelated to K(+) channel openings. TEA (20 mM) increased tone but did not inhibit relaxations to electrical field stimulation (EFS) of enteric nerves. 4-AP relaxed tone, an effect that was abolished and reversed by L-NOARG. 4-AP apparently released NO and acetylcholine from nerves. The putative Cl(-) channel blocker niflumic acid (NFA; 30-100 microM) dose dependently reduced tone, but tone, restored by 10(-6) M carbachol or 20 mM TEA, was still relaxed by EFS and by SNP. 4,4'-Diisothiocyanatostilbene-2, 2'-disulfonic acid (DIDS) at 500 to 1000 microM did not inhibit relaxation to EFS or SNP. The addition of TEA (20 mM) to DIDS (1000 microM) induced tonic and phasic activity and markedly inhibited relaxations to EFS. DIDS plus TEA reduced the relaxations to SNP like TEA alone. Reduction in extracellular ¿Cl(-) by isethionate substitution reduced tone but did not reduce relaxations when tone was restored. The combination of reduced extracellular ¿Cl(-) and TEA did not abolish relaxation to EFS until DIDS was added. Thus, multiple K(+) channels are opened by myogenic NO, and openings of these channels, as well as DIDS-sensitive, undefined mechanisms, are induced when NO is released from nerves or SNP.
PURPOSE: To assess simple trabeculectomy in black Africans with open angle glaucoma. METHODS: We studied retrospectively 80 eyes of 62 patients with primary open angle glaucoma operated by Cairn's trabeculectomy without adjunction of antimetabolites. Thirty seven eyes had a limbal-based conjunctival flap and the others 43 had a fornix-based conjunctival flap. Failures and success were assessed with the Kaplan-Meier's method. RESULTS: Patients were all seen at least 12 months after surgery. The mean follow up was 24 months. At mid-term survey we found complications to be frequent. Pathological blebs occurred in 22.5% (18 cases). The survival probability grew shorter with time. Only 44% of patients were reviewed at 36 months and 29% at 48 months. The success rate (IOP less than 21 mmHg of all glaucoma medications) varied according to the conjunctival flap. It was respectively at 12 months, 24 months and 36 months: 97%, 70 % and 54% with limbal-based flap, and 46%, 18% and 18% with fornix-base flap. The overall rate of tonometric failures was 33.75%. Failures were more often with fornix- based flap (85%). Generally they set in before one year of survey. This was so in 91% of absolute failures and in 87% of relative failures. The failures rate seems to increase with topical polytherapy given more than 12 months before operation. CONCLUSIONS: Trabeculectomy with limbal-based conjunctival flap is at mid-term follow up successful in black Africans. However the following up difficulties in Africa makes it a too delicate assessment objective for long-term results of trabeculectomy.