Impaired nitrergic relaxation in pyloric sphincter of the 6-OHDA Parkinson's disease rat

Patients with Parkinson's disease (PD) often suffer from delayed gastric emptying, but the underlying mechanism remains unclear. We have shown previously that a PD rat model comprising bilateral substantia nigra destruction by 6-hydroxydopamine (6-OHDA rats) exhibits gastroparesis with alteration of neural nitric oxide synthase (nNOS) and acetylcholine in gastric corpus. However, changes in pyloric motility in the 6-OHDA rats have not been characterized. Solid gastric emptying test, immunofluorescence, Western blot, and in vitro pyloric motility recordings were used to assess pyloric motor function in the 6-OHDA rats. The 6-OHDA-treated rats displayed delayed solid gastric emptying and a lower basal pyloric motility index. In the 6-OHDA rats, high K⁺-induced transient contractions were weaker in pyloric sphincters. Electric field stimulation (EFS)-induced pyloric sphincter relaxation was lower in the 6-OHDA rats. N^G-nitro-l-arginine methyl ester (l-NAME), a nonselective inhibitor of NOS, markedly inhibited the EFS-induced relaxation in both control and 6-OHDA rats. Pretreatment of tetrodotoxin abolished the effect of EFS on the pyloric motility. In addition, nNOS-positive neurons were extensively distributed in the pyloric myenteric plexus, whereas the number of nNOS-immunoreactive neurons and the protein expression of nNOS were significantly decreased in the pyloric muscularis of 6-OHDA rats. However, sodium nitroprusside-induced pyloric relaxations were similar between the control and 6-OHDA rats. These results indicate that the pyloric sphincters of 6-OHDA rats exhibit both weakened contraction and relaxation. The latter may be due to reduced nNOS in the pyloric myenteric plexus. The dysfunction of the pyloric sphincter might be involved in the delayed gastric emptying.NEW & NOTEWORTHY Reduced nitrergic neurons in pyloric myenteric plexus potently contributed to the attenuated relaxation in 6-hydroxydopamine (6-OHDA) rats, subsequently affecting gastric emptying. SNP could well improve the relaxation of pylori in 6-OHDA rats. The present study provides new insight into the diagnosis and treatment of delayed gastric emptying in patients with PD.

MicroRNAs of bone marrow mesenchymal stem cell-derived exosomes regulate acute myeloid leukemia cell proliferation and apoptosis

BACKGROUND

Acute myeloid leukemia (AML) is a malignant hematological disease, originating from hematopoiesis stem cell differentiation obstruction and clonal proliferation. New reagents or biologicals for the treatment of AML are urgently needed, and exosomes have been identified as candidate biomarkers for disease diagnosis and prognosis. This study aimed to investigate the effects of exosomes from bone marrow mesenchymal stem cells (BMSCs) on AML cells as well as the underlying microRNA (miRNA)-mediated mechanisms.

METHODS

Exosomes were isolated using a precipitation method, followed by validation using marker protein expression and nanoparticle tracking analysis. Differentially expressed miRNAs were identified by deep RNA sequencing and confirmed by quantitative real-time polymerase chain reaction (qPCR). Cell proliferation was assessed by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt method, and cell cycle progression and apoptosis were detected by flow cytometry. Functional gene expression was analyzed by qPCR and Western blotting (WB). Significant differences were determined using Student's t test or analysis of variance.

RESULTS

BMSCs-derived exosomes effectively suppressed cell proliferation (both P < 0.0001 at 10 and 20 μg/mL) and cell cycle progression (P < 0.01 at G0-G1 stage), and also significantly enhanced cell apoptosis (P < 0.001) in KG-1a cells. There were 1167 differentially expressed miRNAs obtained from BMSCs-derived exosomes compared with KG-1a cell-derived exosomes (P < 0.05). Knockdown of hsa-miR-124-5p in BMSCs abrogated the effects of BMSCs-derived exosomes in regulating KG-1a such as the change in cell proliferation (both P < 0.0001 vs. normal KG-1a cell [NC] at 48 and 72 h). KG-1a cells treated with BMSCs-derived exosomes suppressed expression of structural maintenance of chromosomes 4 (P < 0.001 vs. NC by qPCR and P < 0.0001 vs. NC by WB), which is associated with the progression of various cancers. This BMSCs-derived exosomes effect was significantly reversed with knockdown of hsa-miR-124-5p (P < 0.0001 vs. NC by WB).

CONCLUSIONS

BMSCs-derived exosomes suppress cell proliferation and cycle progression and promote cell apoptosis in KG-1a cells, likely acting through hsa-miR-124-5p. Our study establishes a basis for a BMSCs-derived exosomes-based AML treatment.

Radiofrequency ablation for hepatic hemangiomas: A consensus from a Chinese panel of experts

Recent studies have shown that radiofrequency (RF) ablation therapy is a safe, feasible, and effective procedure for hepatic hemangiomas, even huge hepatic hemangiomas. RF ablation has the following advantages in the treatment of hepatic hemangiomas: minimal invasiveness, definite efficacy, high safety, fast recovery, relatively simple operation, and wide applicability. It is necessary to formulate a widely accepted consensus among the experts in China who have extensive expertise and experience in the treatment of hepatic hemangiomas using RF ablation, which is important to standardize the application of RF ablation for the management of hepatic hemangiomas, regarding the selection of patients with suitable indications to receive RF ablation treatment, the technical details of the techniques, therapeutic effect evaluations, management of complications, etc. A final consensus by a Chinese panel of experts who have the expertise of using RF ablation to treat hepatic hemangiomas was reached by means of literature review, comprehensive discussion, and draft approval.

PIM-1 kinase inhibitor SMI-4a exerts antitumor effects in chronic myeloid leukemia cells by enhancing the activity of glycogen synthase kinase 3β

The development of targeted tyrosine kinase inhibitors (TKIs) has succeeded in altering the course of chronic myeloid leukemia (CML). However, a number of patients have failed to respond or experienced disease relapse following TKI treatment. Proviral integration site for moloney murine leukemia virus-1 (PIM-1) is a serine/threonine kinase that participates in regulating apoptosis, cell cycle, signal transduction and transcriptional pathways, which are associated with tumor progression, and poor prognosis. SMI-4a is a selective PIM-1 kinase inhibitor that inhibits PIM-1 kinase activity in vivo and in vitro. The present study aimed to explore the mechanism underlying the antitumor effect of SMI-4a in K562 and imatinib-resistant K562 (K562/G) cell lines. It was demonstrated that SMI-4a inhibited the proliferation of K562 and K562/G cells using a WST-8 assay. The Annexin V-propidium iodide assay demonstrated that SMI-4a induced apoptosis of K562 and K562/G cells in a dose-, and time-dependent manner. Furthermore, Hoechst 33342 staining was used to verify the apoptosis rate. The clone formation assay revealed that SMI-4a significantly inhibited the colony formation capacity of K562 and K562/G cells. Western blot analysis demonstrated that SMI-4a decreased phosphorylated (p)-Ser9-glycogen synthase kinase (GSK) 3β/pGSK3β and inhibited the translocation of β-catenin. In addition, the downstream gene expression of apoptosis regulator Bax and poly(ADP-ribose) polymerase-1 was upregulated, and apoptosis regulator Bcl-2 and Myc proto-oncogene protein expression levels were downregulated. Immunofluorescence results demonstrated changes in the expression level of β-catenin in the plasma and nucleus. The results of the present study suggest that SMI-4a is an effective drug to use in combination with current chemotherapeutics for the treatment of imatinib-resistant CML.

Zoledronic acid overcomes adriamycin resistance in acute myeloid leukemia cells by promoting apoptosis

Zoledronic acid (ZOL), a nitrogen‑containing bisphosphonate, is widely used in metastatic bone disease. Previous studies indicate that ZOL has marked anti‑leukemia activity, however, the underlying mechanism of action remains to be elucidated. The present study aimed to explore the mechanism of the anti‑leukemia effect of ZOL in leukemia cells. It was observed that ZOL inhibited the proliferation of HL‑60 and adriamycin‑resistant HL‑60 (HL‑60/A) cells using a WST‑8 assay. An Annexin V‑propidium iodide indicated that ZOL induced apoptosis of the two cell types in a dose‑ and time‑dependent manner. Hoechst 33342 staining was also used to verify the levels of apoptosis. The colony formation assay demonstrated that ZOL significantly inhibited colony formation capacity in acute myeloid leukemia (AML) cells. This was achieved by the induction of S‑phase cell cycle arrest, downregulation of B‑cell lymphoma 2 (Bcl‑2) and upregulation of Bcl‑2 associated X protein and cleaved poly (ADP‑ribose) polymerase. The results indicate that ZOL inhibited cell proliferation by inducing apoptosis via the mitochondrial apoptotic pathway and this anti‑leukemic activity appeared notably enhanced in HL‑60/A cells. As ZOL is already available for clinical use, these results indicate that it may be an effective addition to the chemotherapeutic strategies for AML.

RUNX3 plays an important role in As2O3‑induced apoptosis and allows cells to overcome MSC‑mediated drug resistance

The interaction between bone marrow stromal cells and leukemia cells is critical for the persistence and progression of leukemia, and this interaction may account for residual disease. However, the link between leukemia cells and their environment is still poorly understood. In our study, runt‑related transcription factor 3 (RUNX3) was identified as a novel target gene affected by As2O3 and involved in mesenchymal stem cell (MSC)‑mediated protection of leukemia cells from As2O3‑induced apoptosis. We observed induction of RUNX3 expression and the translocation of RUNX3 into the nucleus after As2O3 treatment in leukemia cells. In K562 chronic myeloid leukemia cells, downregulation of endogenous RUNX3 compromised As2O3‑induced growth inhibition, cell cycle arrest, and apoptosis. In the presence of MSC, As2O3‑induced expression of RUNX3 was reduced significantly and this reduction was modulated by CXCL12/CXCR4 signaling. Furthermore, overexpression of RUNX3 restored, at least in part, the sensitivity of leukemic cells to As2O3. We conclude that RUNX3 plays an important role in As2O3‑induced cellular responses and allows cells to overcome MSC‑mediated drug resistance. Therefore, RUNX3 is a promising target for therapeutic approaches to overcome MSC‑mediated drug resistance.

New perspectives of vesicular monoamine transporter 2 chemical characteristics in mammals and its constant expression in type 1 diabetes rat models

Vesicular monoamine transporter 2 (VMAT2) has been exploited as a biomarker of β-cell mass in human islets. However, a current report suggested no immunoreactivity of VMAT2 in the β cells of rat islets. To investigate the cellular localization of VMAT2 in islets further, the pancreatic tissues from monkeys and humans were compared with those of rats and mice. The study was performed using among-species comparisons and a type 1 diabetes model (T1DM) for rats by Western blotting, double-label immunofluorescence, and confocal laser scanning microscopy. We found that VMAT2-immunoreactivity (IR) was distributed peripherally in the islets of rodents, but was widely scattered throughout the islets of primates. Consistent with rodent islets, VMAT2-IR did not exist in insulin (INS)-IR cells but was abundantly present in glucagon (GLU)-IR and pancreatic polypeptide (PP)-IR cells in monkey and human islets. VMAT2-IR had no colocalization with INS-IR in any part of the rat pancreas (head, body, and tail). INS-IR cells were reduced dramatically in T1DM rat islets, but no significant alteration in the proportion of VMAT2-IR cells and GLU-IR cells was observed. Furthermore, a strong colocalization of VMAT2-IR with GLU-IR was distributed in the peripheral regions of diabetic islets. For the first time, the current study demonstrates the presence of VMAT2 in α cells and PP cells but not in β cells in the islets of monkeys and humans. This study provides convinced morphologic evidence that VMAT2 is not present in β cells. There needs to be studies for new markers for β cell mass.

Diagnosis of Felty's syndrome, distinguished from hematological neoplasm: A case report

Felty’s syndrome (FS) is characterized by the three conditions of rheumatoid arthritis (RA), neutropenia and splenomegaly, and occurs in few cases of longstanding erosive RA. Discriminating between rare occurrences of autoimmune diseases and malignancies is crucial. The present study describes the case of a 17-year-old female with a two-year history of RA, presenting with an irregular fever, hepatosplenomegaly and enlarged lymph nodes. The antinuclear antibody titer was 1:320, while antibody results for anti-dsDNA, anti-Sm and rheumatoid factor were negative. The clinical presentation was similar to that of lymphoma. However, the fluorodeoxyglucose-positron emission tomography and biopsy examinations of the liver and cervical lymph node did not support the diagnosis of lymphoma. According to the laboratory results and clinical symptoms, the differential diagnosis indicated FS, and immunosuppressive agents were administered. Two weeks later, the patient no longer had a fever, and the transaminase levels were normal, associated with shrinkage of the liver and spleen.

Dopamine D1 receptors mediate dopamine-induced duodenal epithelial ion transport in rats

Dopamine (DA) is synthesized in gastrointestinal epithelial cells and performs important regulatory effects on the duodenal mucosa. However, the underlying mechanism remains largely unknown. The present study investigated the effect of DA on the duodenal epithelial ion transport in rats by means of short-circuit current (ISC), real-time pH titration, enzyme-linked immunosorbent assay, and immunohistochemistry. The results indicate that basolateral, but not apical, application of DA induced a concentration-dependent ISC downward deflection with an apparent IC50 of 5.34 μmol/L. Basolateral application of dopaminergic receptor D1 (D1) antagonist, SCH-23390, inhibited DA-induced change in ISC (△ISC) in a dose-dependent manner. D1 agonist, SKF38393, mimicked the effect of DA on the ISC. The clear immunoreactivity of D1 subtype D5 (D1b) was at the both apical and basolatoral sides of Brunner's glands and intestinal crypts. Basolateral pretreatment with adenylate cyclase inhibitor, MDL12330A, significantly inhibited DA- and forskolin-induced △ISC. DA and SKF38393 increased the level of intracellular cyclic adenosine monophosphate (cAMP) from 1.55 ± 0.11 to 2.07 ± 0.11 and 5.91 ± 0.25 pmol/L·mg(-1), respectively. Furthermore, the serosal DA-induced △ISC was remarkably inhibited by apical administration of K(+) channel blockers, Ba(2+) and tetraethylammonium, but not by Cl(-) channel blockers. Serosal DA and D1 agonist did not affect duodenal HCO3(-) secretion. In conclusion, the present results demonstrate that serosal DA is able to promote rat duodenal epithelial K(+) secretion, not HCO3(-) secretion through D1-mediated and cAMP-dependent pathway. The study provides a new insight in the modulation of DA on the ion transport of duodenal epithelia in rats.

Alterations in TH- and ChAT-immunoreactive neurons in the DMV and gastric dysmotility in an LPS-induced PD rat model

To study movement disorder in Parkinson's disease (PD), an animal model of PD can be created by injecting lipopolysaccharide (LPS) into the substantia nigra of rats. In addition to body movement disorders, patients with PD often experience gastrointestinal (GI) dysfunction, such as gastroparesis. However, the underlying mechanism of these disorders remains unclear. The dorsal motor nucleus of vagus (DMV) is a well-known visceral nucleus that regulates GI function. The present study investigated alterations in DMV neurons and gastric motility in rats with LPS-induced PD (LPS-PD rats). Gastric motility was recorded using a strain gauge force transducer in vivo. The distributions of tyrosine hydroxylase (TH)- and choline acetyltransferase (ChAT)-positive neurons in the DMV were determined using immunofluorescence and confocal laser microscopy. Our results indicated that in LPS-PD rats, the number of neurons in the substantia nigra, including neurons with TH immunoreactivity, was markedly reduced, although glial cell proliferation was clearly observed. However, enhanced TH immunoreactivity and decreased ChAT immunoreactivity were found in the DMV. Furthermore, weakened gastric motility was recorded in anesthetized LPS-PD rats. In conclusion, rats with LPS-induced PD exhibited gastric dysmotility with an alteration in DMV neurons. This PD model may be used to study autonomic nervous system disorders that are often observed in patients with early-stage PD.

Distribution of dopamine receptors D1- and D2-immunoreactive neurons in the dorsal motor nucleus of vagus in rats

The dorsal motor nucleus of vagus (DMV) plays an important role in the regulation of gastrointestinal function. Dopamine (DA) exerts potent neuromodulatory effects on the motoneurons in the DMV via dopamine receptors (DRs). However, the distribution of DRs and their neurochemical phenotypes in the DMV are unclear. In the present study, the distribution of DRs D1- and D2-immunoreactive (IR) neurons and their neurochemical phenotypes in the DMV of rats were investigated using a double-labeling immunofluorescence technique combined with confocal microscopy. The results indicated that a considerable quantity of D1 and D2 was expressed throughout the DMV. A large amount of choline acetyltransferase (ChAT)-IR and a few tyrosine hydroxylase (TH)-IR neurons were observed in the DMV. Nearly all of the neurons were also D1-IR and D2-IR. In conclusion, the present study demonstrates the wide distribution of D1 and D2 in the cholinergic and catecholaminergic neurons in the DMV of rats. The DRs might play an important role in the regulation of DA on the activity of cholinergic and catecholaminergic neurons in the DMV.

RUNX3 is involved in caspase-3-dependent apoptosis induced by a combination of 5-aza-CdR and TSA in leukaemia cell lines

PURPOSE

Epigenetic therapy has had a significant impact on the management of haematologic malignancies. The aim of this study was to assess whether 5-aza-CdR and TSA inhibit the growth of leukaemia cells and induce caspase-3-dependent apoptosis by upregulating RUNX3 expression.

METHODS

K562 and Reh cells were treated with 5-aza-CdR, TSA or both compounds. RT-PCR and Western blot analyses were used to examine the expression of RUNX3 at the mRNA and protein levels, respectively. Immunofluorescence microscopy was used to detect the cellular location of RUNX3. Additionally, after K562 cells were transfected with RUNX3, apoptosis and proliferation were studied using Annexin V staining and MTT assays.

RESULTS

The expression of RUNX3 in leukaemia cell lines was markedly less than that in the controls. Demethylating drug 5-aza-CdR could induce RUNX3 expression, but the combination of TSA and 5-aza-CdR had a greater effect than did treatment with a single compound. The combination of 5-aza-CdR and TSA induced the translocation of RUNX3 from the cytoplasm into the nucleus. TSA enhanced apoptosis induced by 5-aza-CdR, and Annexin V and Hoechst 33258 staining showed that the combination induced apoptosis but not necrosis. Furthermore, apoptosis was dependent on the caspase-3 pathway. RUNX3 overexpression in K562 cells led to growth inhibition and apoptosis and potentiated the effects of 5-aza-CdR induction.

CONCLUSION

RUNX3 plays an important role in leukaemia cellular functions, and the induction of RUNX3-mediated effects may contribute to the therapeutic value of combination TSA and 5-aza-CdR treatment.

[Significance of DNA methylation status of runx3 gene promoter region in acute leukemia]

This study was aimed to investigate the effects of methylation of runx3 gene promoter on pathogenesis of acute leukemia (AL) and its clinical significance. The methylation of runx3 gene promoter in cells of bone marrow or peripheral blood from 40 cases of AL and 10 healthy persons as well as in CHRF, U937 and K562 cell lines were assuaged by methylation specific polymerase chain reaction (MS-PCR), the expression of runx3 gene were detected with reverse transcription polymerase chain reaction (RT-PCR). The results indicated that no methylation was detected in all of cell lines and healthy persons while expression of runx3 gene could be deteted, methylation of runx3 gene promoter was found in 35% (14/40) AL patients and its percentage was significant higher than that healthy persons (0%), the difference in methylation for runx3 between two kinds of samples was statistically significant (p<0.05), while methylation rate in AML was 30.43% (7/23), ALL was 41.18% (7/17), there was no significant difference between them (p>0.25). All of methylated samples had no expression of runx3 gene. Patients without methylation of runx3 gene had a lower percentage of blasts in bone marrow and a higher complete remission rate of first chemotherapy than those with methylation of runx3 gene. It is concluded that methylation of runx3 gene promoter probably plays a role in the pathogenesis of AL and may have clinical significance in predicting prognosis of AL.

Experimental study on operative methods of pancreaticojejunostomy with reference to anastomotic patency and postoperative pancreatic exocrine function

AIM: To assess the patency of pancreaticoenterostomy and pancreatic exocrine function after three surgical methods.

METHODS: A pig model of pancreatic ductal dilation was made by ligating the main pancreatic duct. After 4 wk ligation, a total of 36 piglets were divided randomly into four groups. The piglets in the control group underwent laparotomy only; the others were treated by three anastomoses: (1) end-to-end pancreaticojejunostomy invagination (EEPJ); (2) end-to-side duct-to-mucosa sutured anastomosis (ESPJ); or (3) binding pancreaticojejunostomy (BPJ). Anastomotic patency was assessed after 8 wk by body weight gain, intrapancreatic ductal pressure, pancreatic exocrine function secretin test, pancreatography, and macroscopic and histologic features of the anastomotic site.

RESULTS: The EEPJ group had significantly slower weight gain than the ESPJ and BPJ groups on postoperative weeks 6 and 8 (P < 0.05). The animals in both the ESPJ and BPJ groups had a similar body weight gain. Intrapancreatic ductal pressure was similar in ESPJ and BPJ. However, pressure in EEPJ was significantly higher than that in ESPJ and BPJ (P < 0.05). All three functional parameters, the secretory volume, the flow rate of pancreatic juice, and bicarbonate concentration, were significantly higher in ESPJ and BPJ as compared to EEPJ (P < 0.05). However, the three parameters were similar in ESPJ and BPJ. Pancreatography performed after EEPJ revealed dilation and meandering of the main pancreatic duct, and the anastomotic site exhibited a variable degree of occlusion, and even blockage. Pancreatography of ESPJ and BPJ, however, showed normal ductal patency. Histopathology showed that the intestinal mucosa had fused with that of the pancreatic duct, with a gradual and continuous change from one to the other. For EEPJ, the portion of the pancreatic stump protruding into the jejunal lumen was largely replaced by cicatricial fibrous tissue.

CONCLUSION: A mucosa-to-mucosa pancreaticojejunostomy is the best choice for anastomotic patency when compared with EEPJ. BPJ can effectively maintain anastomotic patency and preserve pancreatic exocrine function as well as ESPJ.

Transfection of IL-2 and/or IL-12 genes into spleen in treatment of rat liver cancer

AIM: To test the efficacy of gene therapy in rat liver tumor.

METHODS: A retroviral vector GCIL12EIL2PN encoding human IL-2 (hIL-2) and mouse IL-12 (mIL-12) fused gene and its packaging cell were constructed. The packaging cell lines contained of IL-2 and/or IL-12 genes were injected intrasplenically to transfect splenocyte at different time. The therapeutic effect, immune function and toxic effect were evaluated.

RESULTS: The average survival times of the 4 groups using IL genes at days 1, 3, 5 and 7 after tumor implantation were 53.3 ± 3.7, 49.3 ± 4.2, 31.0 ± 2.1 and 24.3 ± 1.4 d respectively in IL-2/IL-12 fused gene group, 25.0 ± 2.5, 23.5 ± 2.0, 18.3 ± 2.4 and 12.0 ± 1.8 d respectively in IL-2 gene treatment group, and 39.0 ± 4.8, 32.0 ± 3.9, 23.0 ± 2.5 and 19.4 ± 2.1 d respectively in IL-12 gene treatment group (P < 0.01, n = 10). In the IL-12/IL-2 fused gene treatment group, 30% of rats treated at days 1 and 3 survived more than 60 d and serum mIL-12 and hIL-2 levels were still high at day 3 after treatment. Compared with IL alone, NK cell activity was strongly stimulated by IL-2/IL-12 gene. Microscopy showed that livers were infiltrated by a number of lymphocytes.

CONCLUSION: IL-2 and/or IL-12 genes injected directly into spleen increase serum IL-2 and IL-12 levels and enhance the NK cell activity, which may inhibit the liver tumor growth. The therapy of fused gene IL-2/IL-12 is of low toxicity and relatively high NK cell activity. Our data suggest that IL-2/IL-12 fused gene may be a safe and efficient gene therapy for liver tumor. The gene therapy should be administrated as early as possible.

[The separation of three basic drugs with carboxymethyl-poly-beta-cyclodextrin as chiral additive by capillary electrophoresis]

Five cyclodextrin derivatives, namely phosphate ester beta-CD, carboxymethyl-beta-CD(CM-beta-CD), bis-[6-oxygen-(beta-carboxymethyl-succinic acid-4-ester)] beta-CD(F-CM-beta-CD), beta-CD polymer(P-beta-CD), carboxymethyl-poly-beta-CD (CD-P-beta-CD), were used as chiral selector for separation of three basic drugs, lobeline, thiopendonesodium, flunarizine by capillary zone electrophoresis (CZE). All the five cyclodextrins have chiral separation ability to lobeline. P-beta-CD and CM-P-beta-CD have chiral recognition to thiopentonesodium and flunarizine. The results indicate that via optimizing separation conditions by varying pH and the concentration of chiral selectors the three racemic drugs could be baseline separated with 2% P-beta-CD or 0.5% CM-P-beta-CD in the buffer of 30 mmol/L Tris-H3PO4. And the best resolution ranging from 4 to 35 with CM-P-beta-CD as chiral additive was obtained within 10 min. The results were much better than those reported in other references.

Effect of heparin-surface-modified poly(methyl methacrylate) intraocular lenses on the postoperative inflammation in an Asian population

PURPOSE

To compare the efficacy of heparin-surface-modified (HSM), poly(methyl methacrylate) (PMMA) posterior chamber intraocular lenses (IOLs) with that of unmodified PMMA IOLs in reducing postoperative complications caused by inflammatory reactions after extracapsular cataract extraction in an Asian population.

SETTING

Departments of Ophthalmology, University of Malaya, Kuala Lumpur, Malaysia, and Tan Tock Seng Hospital, Singapore.

METHODS

In a randomized, double-blind study performed at two centers, 51 patients received an HSM PMMA lens and 48, an unmodified PMMA IOL. Cell and pigment deposits were evaluated by slitlamp at 1 to 6 days, 2 to 3 weeks, and 3 to 6 months postoperatively.

RESULTS

Significantly more eyes with unmodified IOLs had inflammatory cell deposits than those with HSM IOLs at 3 to 6 months (P < .001) and 12 to 14 months (P = .018) postoperatively. The HSM group also had significantly fewer cell deposits per patient at these two follow-ups. Significantly more eyes in the non-HSM group had pigment deposits 3 to 6 months after surgery (P = .049). One year postoperatively, about 85% of patients in both groups had a best corrected visual acuity of 0.5 or better.

CONCLUSION

Heparin surface modification significantly reduced the inflammatory response to PMMA IOLs in an Asian population for at least 12 to 14 months.

Pupil abnormalities on the first postoperative day after cataract surgery

Most, if not all, ophthalmologists strive to achieve a round pupil after cataract surgery with posterior chamber lens implantation. The presence of pupil abnormalities and iris modifications is cosmetically undesirable and may affect the quality of postoperative vision. The pupillary motility may be changed which will in turn affect both pupillary light reflexes and pupillary dilatation during fundus examination. In this paper, we prospectively studied 2 groups of patients who underwent uncomplicated cataract surgery with posterior chamber lens implantation; 100 patients who had planned extracapsular cataract extraction (ECCE), and 130 patients who underwent phacoemulsification. On the first postoperative day, we found a 16% rate of pupil abnormalities in the group which underwent ECCE surgery while only 5.3% of the phacoemulsification group had pupil abnormalities. There were different causes in which the two groups. The most common cause of pupil abnormality after ECCE was due to iris sphincter rupture, whereas the most common cause after phacoemulsification was due to iris trauma during phacoemulsification. These pupil abnormalities are the direct consequence of factors in surgery and we suggest ways to minimize the occurrence of such abnormalities in cataract surgery.

Laser iridotomies in Asian eyes

Argon laser iridotomy and Nd:YAG (Neodymium: Yttrium-Aluminium-Garnet) iridotomy are the two established techniques of laser iridotomies. However, in the thicker and more heavily pigmented Asian irides, they are associated with higher complication and failure rates. A third iridotomy technique that is recently described is the sequential argon-YAG laser iridotomy. Here, both the argon and Nd:YAG laser are used serially at the same sitting to achieve a patent iridotomy. By using the argon to make the initial bore and the Nd:YAG laser to complete the perforation, the technique is able to effectively combine most of the advantages of both lasers whilst avoiding their disadvantages. It is possibly the ideal iridotomy technique to use in the Asian irides.

A retrospective study of cataract surgery in the Singapore General Hospital in 1990

Nine hundred and ninety-five consecutive cases of cataract extraction with or without lens implantation performed within the first three months of 1990 in the Singapore General Hospital were examined retrospectively. Of the 995 cases, 874 (87.84%) were deemed to have adequate postoperative evaluation at an average of 12.5 months. Of these cases, 79.52% (695 eyes) obtained a visual acuity of 6/12 or better. When cases with pre-existing causes of poor vision were excluded, 90.25% of cases obtained a visual acuity of 6/12 or better. If potentially treatable causes of postoperative poor vision (such as posterior capsule opacification awaiting Nd:YAG laser capsulotomy and high astigmatism prior to suture removal) were further excluded from analysis, this figure would rise to 93.66%. The incidence of posterior capsule rupture was 1.4%. Factors affecting visual success included patient age, lens hypermaturity and duration of surgery.

A review of anaesthesia in ophthalmology

In this article, we review the methods of anaesthesia commonly used in ophthalmology in Singapore. These include topical, local, regional and general anaesthesia. Topical and local anaesthesia is adequate for most outpatient procedures. The most common form of regional anaesthesia in Singapore is still retrobulbar anaesthesia. General anaesthesia is used in children and when more extensive procedures are performed.

Effect of heparin surface modification of polymethylmethacrylate intraocular lenses on signs of postoperative inflammation after extracapsular cataract extraction. One-year results of a double-masked multicenter study

PURPOSE

A heparin surface modified posterior chamber intraocular lens (IOL) was compared with a conventional polymethylmethacrylate (PMMA) IOL regarding postoperative complications caused by inflammation.

METHODS

Five hundred twenty-four patients from 10 different centers were included in a parallel group, double-masked, multicenter study.

RESULTS

The cumulative number of patients with inflammatory cellular deposits on their IOLs during the first postoperative year differed significantly in favor of the heparin surface modified group, with 29.8% of the patients having cellular deposits compared with 48.8% of patients in the control group. Cellular deposits were observed most frequently at 3 months after surgery, and the difference between the groups was most pronounced and statistically significant at this time. The same results were seen at 1 year, but the difference was not significant. The number of cellular deposits per patient, however, was significantly lower in the heparin surface modified group at 1 year. Cumulatively, there were significantly more patients with posterior synechiae in the PMMA group than in the heparin surface modified group during the 1-year follow-up. Complications were few and comparable between the groups.

CONCLUSION

The results of this study indicate that heparin surface modification reduces the inflammatory response to PMMA IOLs.

Clinical experience with the laser indirect ophthalmoscope

Laser delivery through a binocular indirect ophthalmoscope is a relatively recent addition to the armamentarium in vitreoretinal work. Hitherto to our experience, it had not been used in this region. This paper documents our initial experience with a laser indirect ophthalmoscope used successfully in the retinal photocoagulation of patients with diabetic retinopathy, venous occlusions, peripheral retinal holes and lattice degenerations and in post-vitrectomy cases. We found that this mode of laser delivery offered the advantages of an increased field of view of the retina, improved access to the retinal periphery and better patient comfort. It enabled laser treatment of patients with physical or mental handicaps who are unable to sit at the slit-lamp. It is the first system that can deliver laser treatment to patients in the pediatric age-group. It may also be valuable in Stage III retinopathy of prematurity, Coats disease, pneumatic retinopexy, and anterior hyaloidal neovascular proliferations. The chief drawback with this system are the lower magnification and sensitivity to inadvertent movement by the patient or surgeon. We concluded that this mode of laser delivery is a useful adjunct to the slit lamp system and can in some cases be the preferred mode of laser therapy.

Pseudohypopyon--an unusual presenting sign in retinoblastoma

Retinoblastoma is the most common intraocular malignancy of childhood. A case of pseudohypopyon as an unusual first sign of retinoblastoma is presented. More common clinical presentations and diagnosis of this disease are also discussed. As some cases of retinoblastoma can mimic non-malignant disease, it is important that the physician have a high index of suspicion for this tumour.

AIDS-CMV retinitis: Singapore's first cases

Since April 1988, four cases of AIDS-CMV retinitis were diagnosed in Singapore. Two patients were given intravenous ganciclovir. Clinical response was good but recurrent episodes of breakthrough infection occurred in one patient despite maintenance therapy. Another patient was started on intravenous foscarnet. The fourth patient succumbed to systemic AIDs-related infection before therapy could be started. AIDS-CMV retinitis is a new disease entity in Singapore. With increasing number of AIDS patients, more cases can be expected in the near future. Early treatment and long term maintenance therapy is essential for preserving sight.

Effectiveness of silicone oil removal from rabbit eyes

Silicone oil (1000 and 12,500 cs) and fluorosilicone oil (1000 and 10,000 cs) were dyed red and injected into a gas-created space in the vitreous cavity of 51 rabbit eyes. Later the oils were removed from the vitreous cavity either by lavage with balanced salt solution (group 1, 27 eyes) or by injecting a sodium hyaluronate solution, followed by lavage with balanced salt solution (group 2, 24 eyes). The average amount of oil retained in the vitreous cavity in group 1 was 0.0675 ml, and occasionally a large amount of oil was found (more than 0.1 ml in 30% of eyes). The average amount of oil retained in group 2 was 0.0114 ml, and no eye retained more than 0.1 ml of oil. The difference between the two groups was statistically significant (p less than 0.02), but there was no significant difference in oil retention within either group between the different kinds of oils, or between different viscosities of oil. The data suggest that residual oil can persist in the vitreous cavity despite thorough lavage, and that removal of silicone oil with the use of a sodium hyaluronate solution significantly lowers the risk of a large amount of residual silicone oil that is occasionally seen with conventional removal methods.