1
|
Nickel-Catalyzed α-Carbonylalkylarylation of Vinylarenes: Expedient Access to γ,γ-Diarylcarbonyl and Aryltetralone Derivatives. Angew Chem Int Ed Engl 2020; 59:8047-8051. [PMID: 32059062 PMCID: PMC7274890 DOI: 10.1002/anie.201913435] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Indexed: 11/10/2022]
Abstract
We report a Ni-catalyzed regioselective α-carbonylalkylarylation of vinylarenes with α-halocarbonyl compounds and arylzinc reagents. The reaction works with primary, secondary, and tertiary α-halocarbonyl molecules, and electronically varied arylzinc reagents. The reaction generates γ,γ-diarylcarbonyl derivatives with α-secondary, tertiary, and quaternary carbon centers. The products can be readily converted to aryltetralones, including a precursor to Zoloft, an antidepressant drug.
Collapse
|
2
|
K2CO3-Catalyzed Synthesis of 2,5-Dialkyl-4,6,7-tricyano-Decorated Indoles via Carbon–Carbon Bond Cleavage. Org Lett 2020; 22:3268-3272. [DOI: 10.1021/acs.orglett.0c01057] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
3
|
Nickel‐Catalyzed α‐Carbonylalkylarylation of Vinylarenes: Expedient Access to γ,γ‐Diarylcarbonyl and Aryltetralone Derivatives. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201913435] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
4
|
Ni(I)-Catalyzed β,δ-Vinylarylation of γ,δ-Alkenyl α-Cyanocarboxylic Esters via Contraction of Transient Nickellacycles. ACS Catal 2019; 9:10887-10893. [PMID: 34084651 PMCID: PMC8171255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We disclose a transmetalation-initiated Ni(I)-catalyzed regioselective β,δ-vinylarylation of γ,δ-alkenyl α-cyanocarboxylic esters with vinyl triflates and arylzinc reagents. This reaction proceeds via contraction of six-membered nickellacycles to five-membered nickellacycles to form carbon-carbon bonds at the nonclassical homovicinal sites, and it provides expeditious access to a wide range of complex aliphatic α-cyanoesters, α-cyanocarboxylic acids, dicarboxylic acids, dicarboxylic acid monoamides, monocarboxylic acids, nitriles, and spirolactones. Control, deuterium labeling, and crossover experiments indicate that (i) the nickellacycle contraction occurs by β-H elimination, followed by hydronickellation on transiently formed alkenes, and (ii) the Ni species are stabilized as Ni-enolates.
Collapse
|
5
|
Ni(I)-Catalyzed β,δ-Vinylarylation of γ,δ-Alkenyl α-Cyanocarboxylic Esters via Contraction of Transient Nickellacycles. ACS Catal 2019. [DOI: 10.1021/acscatal.9b03574] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
6
|
Concise Synthesis of a Potential 5-Lipoxygenase Activating Protein (FLAP) Inhibitor and Its Analogs through Late-Stage Alkene Dicarbofunctionalization. Org Process Res Dev 2019. [DOI: 10.1021/acs.oprd.9b00199] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
7
|
Synergistic Bimetallic Ni/Ag and Ni/Cu Catalysis for Regioselective γ,δ-Diarylation of Alkenyl Ketimines: Addressing β-H Elimination by in Situ Generation of Cationic Ni(II) Catalysts. J Am Chem Soc 2018; 140:15586-15590. [DOI: 10.1021/jacs.8b09401] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
8
|
Ni-Catalyzed Regioselective β,δ-Diarylation of Unactivated Olefins in Ketimines via Ligand-Enabled Contraction of Transient Nickellacycles: Rapid Access to Remotely Diarylated Ketones. J Am Chem Soc 2018; 140:7782-7786. [DOI: 10.1021/jacs.8b03163] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
9
|
Strategies toward Dicarbofunctionalization of Unactivated Olefins by Combined Heck Carbometalation and Cross-Coupling. J Org Chem 2018; 83:3013-3022. [DOI: 10.1021/acs.joc.7b03128] [Citation(s) in RCA: 198] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
10
|
Ni-Catalyzed Regioselective Dicarbofunctionalization of Unactivated Olefins by Tandem Cyclization/Cross-Coupling and Application to the Concise Synthesis of Lignan Natural Products. J Org Chem 2018; 83:2920-2936. [DOI: 10.1021/acs.joc.8b00184] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
11
|
Ni-Catalyzed Regioselective 1,2-Dicarbofunctionalization of Olefins by Intercepting Heck Intermediates as Imine-Stabilized Transient Metallacycles. J Am Chem Soc 2017; 139:10653-10656. [DOI: 10.1021/jacs.7b06340] [Citation(s) in RCA: 156] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
12
|
Abstract
Dental implants have shown great success in recent years. However, in certain circumstances they can suffer from complications. It usually results from a combination of infection and host inflammatory responses or a lack thereof. This report documents an extra-oral cutaneous fistula associated with an osseointegrated dentoalveolar implant.
Collapse
|
13
|
Preferential targeting of co-evolving Gag residues in long-term non progressors. Retrovirology 2012. [PMCID: PMC3441664 DOI: 10.1186/1742-4690-9-s2-p278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
14
|
Deaths in children during an outbreak of hand, foot and mouth disease in Peninsular Malaysia--clinical and pathological characteristics. THE MEDICAL JOURNAL OF MALAYSIA 2005; 60:297-304. [PMID: 16379183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
From July through December 1997, 11 previously healthy children in Peninsular Malaysia succumbed to an illness clinically characterised by an acute severe refractory left-ventricular failure, following a brief prodromal illness, in the midst of an outbreak of hand, foot and mouth disease (HFMD), similar to the reported experience in Sarawak and Taiwan. Retrospective reviews of the clinical features and results of laboratory, pathological and virological investigations of cases were conducted. The median age of the 11 case-patients was 31 months (range, 13 to 49 months); 6 were males. A brief prodromal illness of 3 days (range, 2 to 5 days) was characterised by fever (axillary temperature > 38 degrees C) (100%), oral ulcers (72%), extremity rashes (45%) and significant vomiting (55%). Upon hospitalisation, 7 of 11 case-patients had features suggestive of cardiogenic shock, while 4 of 11 case-patients developed shock during hospitalisation as evidenced by marked sustained tachycardia (heart rate > or = 180 beats per minute), poor peripheral pulses and peripheral perfusion, mottled extremities, pulmonary oedema (haemorrhagic pulmonary secretions in 8 of 11 cases during tracheal intubation, often precipitated by conservative crystalloid boluses, and radiographic evidence of acute pulmonary oedema in 5 of 7 cases) and markedly impaired left ventricular function on echocardiographic examination (7 of 7 cases). Three of 4 case-patients had aseptic meningitis while one case-patient also had an acute flaccid paraparesis. Despite supportive therapy, death occurred within a median of 13.4 hours following hospitalization. Post-mortem findings (all 8 specimens examined) consistently demonstrated brain-stem encephalitis with foci of neuronal necrosis and micro-abscesses. None of the 11 specimens examined revealed histological evidence of myocarditis. Enterovirus 71 (EV71) was detected in 10 of 11 case-patients, many (7) from various sterile tissue sites (5 from central nervous tissues). No other viruses were isolated or identified. Clinical features and pathological studies closely paralleled the reported experience in Sarawak and Taiwan. The uniform necropsy findings of necrotizing brain-stem encephalitis coupled with essentially normal myocardial histology, in concert with the concurrent and consistent detection of EV71 points to a primary EV71 encephalitis; as yet unclear neurogenic mechanisms may account for the cardiovascular manifestations.
Collapse
|
15
|
|
16
|
Upper genital schistosomiasis mimicking an ovarian tumour. THE MEDICAL JOURNAL OF MALAYSIA 2000; 55:371-5. [PMID: 11200720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Schistosomiasis is a widely prevalent disease in the world and usually involves the gastro-intestinal and urinary tract. The involvement of the female genital tract has been well-established in S. haematobium infections and is rare with S. japonicum infections. This case involves a Filipino female who was admitted to the University Hospital Kuala Lumpur for right iliac fossa pain and was diagnosed initially as acute appendicitis. Ultrasound showed a multi-septated pelvic cyst leading to a provisional diagnosis of ovarian torsion. Intraoperatively a right parovarian cyst was detected and removed. Histology revealed a congested cyst wall with areas of haemorrhage with several viable and calcified eggs of S. japonicum measuring 85 microns x 62 microns. Within the cystic cavity blood admixed with eggs were seen. Confirmation was carried out by using the indirect haemagglutination (IHA) test. This is a first report of upper genital schistosomiasis mimicking an ovarian tumour.
Collapse
|
17
|
Amoebiasis: a 10 year retrospective study at the University Hospital, Kuala Lumpur. THE MEDICAL JOURNAL OF MALAYSIA 1999; 54:296-302. [PMID: 11045054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
A hospital based retrospective study of amoebiasis was carried out for a ten-year period at the University Hospital, Kuala Lumpur. Of the 51 cases traced, 30 (59%) had amoebic dysentery, 20 (39%) were amoebic liver abscess (ALA) and one patient had both conditions. Entameoba histolytica trophozoites were identified in 13 (43%) of the amoebic dysenteric stools and 9 (30%) from biopsy. Of the 20 (39%) ALA cases, only one showed parasites in the stool and biopsy. Majority of the patients with dysentery were Malays while Chinese comprised 40% with ALA. Males predominated overall with a male female ratio of 3:1, while for ALA it was 9:1. Most of ALA were single (71.4%) and were localised in the right lobe. The majority of the patients were unemployed. Eighty three percent (83%) of the patients presented with diarrhoea or dysentery followed by abdominal pain while those with ALA had fever, chills, rigors and pain in the right hypochondrium. Eighty percent of the ALA cases showed hepatomegaly. All patients responded to treatment with metronidazole.
Collapse
|
18
|
Ileal strongyloidiasis in a Malaysian patient. THE MEDICAL JOURNAL OF MALAYSIA 1999; 54:361-3. [PMID: 11045064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
|
19
|
Epidemiological aspects of aquaculture in relation to fish borne trematodiasis in Malaysia. THE SOUTHEAST ASIAN JOURNAL OF TROPICAL MEDICINE AND PUBLIC HEALTH 1998; 28 Suppl 1:54-7. [PMID: 9656350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Epidemiological studies have been conducted to determine the association between fish and disease. The fish were obtained from rivers, streams, ponds and lakes but few from aquaculture farms. While no defined studies have been carried out in Malaysia, baseline data show that fish obtained from aquaculture farms (mixed farming) contributed to cases of opisthorchiasis and clonorchiasis.
Collapse
|
20
|
Gastric strongyloidiasis in a Malaysian patient. THE SOUTHEAST ASIAN JOURNAL OF TROPICAL MEDICINE AND PUBLIC HEALTH 1997; 28:158-60. [PMID: 9322300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Strongyloides stercoralis infection is of low prevalence in Malaysia. We report an unusual case presenting primarily with gastric symptoms. The patient was a 72 years old Chinese male admitted for progressive weight loss and abdominal bloating. Gastroscopic examination revealed mucosal prepyloric elevations in the gastric mucosa. Gastric strongyloidiasis was confirmed by the presence of adult forms, as well as ova and larval rhabditiform stages of the worm in the gastric mucosal crypts. We believe that this is the first histologically documented case of gastric strongyloidiasis in Malaysia.
Collapse
|
21
|
Prevalence of giardiasis among Malaysian primary school children. THE MEDICAL JOURNAL OF MALAYSIA 1996; 51:475-9. [PMID: 10968037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Giardiasis, a gastrointestinal disease caused by Giardia intestinalis is endemic in Malaysia. The prevalence rate has been reported to range from 1.4% to 11.1%. The present study was undertaken between 1992-1994 in three health districts in three states viz. Pahang, Negeri Sembilan and Selangor. Seven thousand five hundred and fifty seven (7557) primary school children between the ages of 6-12 years from the lower socio-economic groups were screened. The prevalence was 0.21%. The study suggests that improved water supply, toilet facilities and sanitation have lowered the prevalence of a waterborne disease in the areas surveyed.
Collapse
|
22
|
Abstract
Human dirofilariasis is a rare infection in Malaysia. Thus far, only two human cases have been reported viz. Dirofilaria immitis and D. (Nochtiella) repens and in both instances, adult worms were recovered from infected patients. The two cases reported in the present study, one from Melaka and the other from Penang, were diagnosed histologically. Based on the diagnostic criteria for identifying Dirofilaria in tissue sections, the parasites were identified as D. (Nochtiella) repens.
Collapse
|
23
|
Food-borne parasitoses in Malaysia epidemiological assessment and research needs. JOURNAL OF THE ROYAL SOCIETY OF HEALTH 1995; 115:178-85. [PMID: 7643345 DOI: 10.1177/146642409511500311] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Food-borne parasitic zoonoses have emerged as a major public health problem in many countries and are posing a medical challenge. They are not only important from the economic point of view but also because of their severe sequelae. In Malaysia, these parasitoses are a tip of an iceberg problem. The article documents all the food-borne parasitic zoonoses reported in Malaysia. An epidemiological assessment of the diseases with research needs is highlighted.
Collapse
|
24
|
Clonorchiasis/opisthorchiasis in Malaysians case reports and review. THE MEDICAL JOURNAL OF MALAYSIA 1995; 50:182-6. [PMID: 7565193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Clonorchiasis and opisthorchiasis are snail-transmitted trematode infections. The disease is endemic in many parts of Asia. Local case reports have been predominantly in Chinese with a history of travel to endemic countries. Thus far, 20 cases of liver fluke infestation have been reported in this country. This report presents another two cases of clonorchiasis and a case of opisthorchiasis. We also briefly review pertinent aspects of the disease.
Collapse
|
25
|
Tropical gastrointestinal disease: hepatosplenic schistosomiasis--pathological, clinical and treatment review. Singapore Med J 1994; 35:616-21. [PMID: 7761889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
S. mansoni and S. japonicum complex schistosomes cause hepatosplenic and hepatointestinal schistosomiasis. The prevalence and incidence of this disease is increasing in all the endemic areas. Hepatosplenic schistosomiasis is seen in a small subset of clinically infected patients and represents a good model of intrahepatic portal hypertension characterised by a presinusoidal portal block and a well preserved liver parenchyma. Symmers' fibrosis is seen in a significant proportion of patients with high worm load. While the pathogenesis of Symmers' pipe stem fibrosis has not been well established, experimental and clinical data point to egg induced granulomata. The main consequences are presinusoidal portal hypertension, oesophageal varices and hepatosplenomegaly. The most striking symptoms are haematemesis or melena secondary to variceal and gastrointestinal bleeding. Cofactors associated with the pathogenesis include aflatoxins, malnutrition, alcoholism, hepatitis B and C virus. While stool examination is the best technique for diagnosis, a number of immunological tests though sensitive are not specific. Ultrasonography is sensitive for detection of Symmer's fibrosis. Praziquantel and oxaminiquine are drugs found to be effective in the treatment of hepatosplenic schistosomiasis. Recently beta-blockers have been found to be effective in the treatment of gastrointestinal rebleeding. Endoscopic sclerotherapy has been found to be effective for treatment of bleeding oesophageal varices. The treatment of choice for portal hypertension is oesophagogastric devascularization with splenectomy (EGDS).
Collapse
|
26
|
The prevalence of cryptosporidiosis in children and adults at University Hospital, Kuala Lumpur. THE MEDICAL JOURNAL OF MALAYSIA 1993; 48:293-296. [PMID: 8183141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A total of 320 faecal specimens obtained from 295 patients (192 children and 103 adults) with diarrhoea and 47 faecal specimens from healthy adults were screened for Cryptosporidium oocysts. Faecal specimens were first screened by modified Ziehl Neelsen stain and specimens with oocysts were confirmed by direct immunofluorescence technique. Cryptosporidium oocysts were detected in 4 children but not in normal healthy adults or in diarrhoeic adults.
Collapse
|
27
|
Human isosporiasis in an AIDS patient--report of first case in Malaysia. THE MEDICAL JOURNAL OF MALAYSIA 1993; 48:355-360. [PMID: 8183153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
An AIDS patient with multiple opportunistic infections (Candida, Pneumocystis carinii and Isospora belli) was identified at the University Hospital, Kuala Lumpur. The patient presented with profuse diarrhoea associated with lethargy, anorexia and weight loss. Routine stool examination showed Isospora belli oocysts. The infection responded to treatment with trimethroprim-sulfamethoxazole but relapse occurred 8 weeks later. This represents the first documented case of isosporiasis to occur in an AIDS patient in Malaysia.
Collapse
|
28
|
Hepatosplenic lesions induced by experimental Schistosoma malayensis in rabbits. THE SOUTHEAST ASIAN JOURNAL OF TROPICAL MEDICINE AND PUBLIC HEALTH 1993; 24:333-9. [PMID: 8266238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Two groups of three rabbits each were infected with 250 cercariae of the Baling and Koyan strain of Schistosoma malayensis. Changes induced by both strains included periportal hepatocellular necrosis and fibrosis. Vascular changes such as portal phlebitis and thrombophlebitis and varying degrees of pericholangitis were also present. Amyloid deposition was noted. A comparative study of the changes induced in rabbits by S. malayensis, S. mekongi and S. japonicum showed that the hepatic lesions induced by the Baling strain of S. malayensis were similar to that induced by S. japonicum, and were more severe than that induced by S. mekongi or the Koyan strain.
Collapse
|
29
|
Pulmonary pathology in rabbits infected with the Baling and Koyan strains of Schistosoma malayensis. THE SOUTHEAST ASIAN JOURNAL OF TROPICAL MEDICINE AND PUBLIC HEALTH 1992; 23:711-5. [PMID: 1298078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Two distinct strains of Schistosoma malayensis exist in Malaysia (designated the Baling and Koyan strains). Both these strains show intraspecific variations in pathology (Greer et al, 1988). To evaluate the differences in the pulmonary pathology resulting from infections of the two different strains of Malaysian schistosome, a total of 20 experimental rabbits were infected, 10 each with cercariae of the Koyan strains. Pathological changes were studied over a period of 28 weeks. Granulomas in the lung occurring as a result of infection with the Baling strain were compared with those caused by infection with the Koyan strain. Although both strains produced parenchymatous and alveolar lesions, granulomas caused by the Baling strain of Malaysian schistosome were more numerous and larger (when comparing mean diameter as well as area of granuloma, p < 0.05). In addition, pulmonary vascular hypertensive changes were present in Baling strain infected rabbits. These comprised of pulmonary arteriolar endothelial swelling and damage, intimal elastosis and medial hypertrophy. Angiitis and pulmonary periphlebitis were also noted occasionally. In contrast, Koyan strain infection resulted in fewer and smaller granulomas. Pulmonary vascular changes were minimal.
Collapse
|
30
|
Epidemiology of dengue/dengue hemorrhagic fever in Malaysia--a retrospective epidemiological study. 1973-1987. Part II: Dengue fever (DF). Asia Pac J Public Health 1992; 6:126-33. [PMID: 1342799 DOI: 10.1177/101053959200600302] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Dengue fever (DF) has been endemic in Malaysia since 1902 and reached epidemic proportions in 1973. The incidence rate of the disease in 1973 was 5.4 cases per 100,000 and reached 10.4 cases per 100,000 in 1987. The Chinese are the main ethnic community affected showing an overall morbidity rate of 9.0 cases per 100,000 followed by Malays 2.9 cases per 100,000 and Indians 2.4 cases per 100,000. The ethnic race ratio between Chinese, Malays and Indians which was 3.7:1:1.3 in 1975 reached 3.7:1:0.9 in 1987. The attack rates were observed to be higher in the males. The mean male:female ratio among Chinese was 1.1:1, while for Malays and Indians it was 1.5:1. The age-specific morbidity rate was highest in the 10- to 19-year age group followed by the 20- to 29-year age group. Epidemics of dengue fever were found to occur seasonally with the appearance of two peaks, viz. one in June and the other in August. Dengue fever, a rural disease before, has established itself as an urban disease.
Collapse
|
31
|
Epidemiology of dengue/dengue hemorrhagic fever in Malaysia--a retrospective epidemiological study 1973-1987. Part I: Dengue hemorrhagic fever (DHF). Asia Pac J Public Health 1992; 6:15-25. [PMID: 1308765 DOI: 10.1177/101053959300600203] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Dengue hemorrhagic fever (DHF), though endemic in the sixties, emerged as a major public health problem in Malaysia from 1973 onwards. The incidence rate of DHF which was 10.1 per 100,000 in 1973 has fallen down to 1.9 per 100,000 in 1987 with a mean case fatality rate of 6.4 per 100 persons. The Chinese appear to be more prone to DHF with the highest mean morbidity rate of 5.5 per 100,000 and case fatality rate of 6.1%. The incidence of DHF is higher in the males with a higher case fatality rate in females. Male Chinese appear to be mainly affected. The overall age-specific incidence rate is highest in two age groups, viz. 5-9 years and 10-19 years of age with a mean morbidity rate of 4.9 cases per 100,000. The mean age-specific case fatality rate was highest in the 0-4 years age group. Dengue hemorrhagic fever is predominantly an urban disease in Malaysia with a mean incidence rate of 5.3 cases per 100,000 as opposed to 1.2 cases per 100,000 being reported from rural areas. The mean overall incidence of deaths in the urban area is 0.5 compared to 0.1 per 100,000 for rural areas. There is a marked seasonal correlation between DHF cases and rainfall, with a peak in August. While all four serotypes of dengue viruses are found in Malaysia, Den 2 appears to be isolated with greater frequency during all the epidemics.
Collapse
|
32
|
Induction of intestinal lesions in rabbits with Koyan and Baling strains of Schistosoma malayensis Sp N. THE SOUTHEAST ASIAN JOURNAL OF TROPICAL MEDICINE AND PUBLIC HEALTH 1992; 23:92-7. [PMID: 1523486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Schistosoma malayensis Sp N is a putative new species of schistosome discovered in Peninsular Malaysia in 1973. This paper comprises the first report on the detailed gastrointestinal pathology present in rabbits infected with strains of the parasite. Two different strains of schistosome--the Baling and Koyan strains--from two different ecosystems were used to infect inbred rabbits and the resulting pathophysiology was studied. Our results showed that the Baling strain of S. malayensis was more virulent than the Koyan strain and produced nodular, segmental circumferential lesions and large bilharziomas measuring 1-7 cm in diameter in the distal jejunum, ileum and the ileo-caecal junction. The findings indicate that the Baling strain of S. malayensis was more pathogenic for rabbits as compared with the Koyan strain--in relation to the gross pathology of the gut and the tissue egg load. Earlier reports have shown that rabbits infected with S. japonicum induces significant intestinal lesions in rabbits (Cheever et al, 1980 a,b) but these animals are refractory to infection with S. mekongi (Byram and Lichtenberg, 1980). Our studies show that the two strains of S. malayensis adapted well in rabbits. It is also established that in rabbits, the virulence of the Baling strain of S. malayensis is greater than that of S. mekongi and approximates that of S. japonicum.
Collapse
|
33
|
Epidemiological assessment of parasitic zoonoses in Malaysia. THE SOUTHEAST ASIAN JOURNAL OF TROPICAL MEDICINE AND PUBLIC HEALTH 1991; 22 Suppl:337-9. [PMID: 1822920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Food-borne parasitic zoonoses are emerging as major public health problems in most countries because they are widespread and pose a medical challenge. Not only are they important from an economic standpoint, but they also cause severe sequalae in all those affected. The extent of parasitic zoonoses in Malaysia is considered a "tip of the iceberg" problem. Cases of zoonotic diseases, like porocphaliasis, sarcocystosis, toxoplasmosis, cysticercosis, hydatidosis, echinostomiasis, and gnathostomiasis are traced and documented. An epidemiologic reassessment of methods is suggested to determine the extent of these parasitoses in Malaysia.
Collapse
|
34
|
Abstract
Schistosomiasis, a grave and debilitating disease of socioeconomic importance, is increasing in incidence despite concerted efforts to control and contain the disease in all the endemic areas. While a multipronged method of control using health education, sanitation and snail control has been used, chemotherapy and chemoprophylaxis play the most important and crucial role in containing/preventing the transmission of the disease. Schistosomicides such as antimonials were introduced, as early as the 1990s as the drugs of choice and continued to be used until the early 1960s. The antimonials were administered intravenously, and produced severe side effects; the various variables that determined their effects at the site of action made their application difficult and adversely affected their use in large scale chemotherapy. The antimonials were then replaced by hycanthone and lucanthone which were administered intramuscularly. These drugs produced immediate side effects such as hepatotoxicity and gastrointestinal disturbances, and were consequently withdrawn. It was then decided that the alternative was to produce synthetic drugs that could be administered orally. Niridazole, oxamniquine, and metrifonate were introduced as schistosomicidal agents, with drugs like oltipraz and amoscanate still at clinical trial phase. Therapeutic doses of drugs like hycanthone, niridazole and amoscanate have been found to cause many major side effects. A significant advance in the control of schistosomiasis chemotherapy is the introduction of a relatively safe, effective, broad spectrum oral helminthic agent, praziquantel. Studies have also shown that oxamniquine is as effective as praziquantel in eliminating intestinal S. mansoni infection, and metrifonate is as effective as praziquantel in eliminating urinary S. haematobium and S. mansoni infections. Praziquantel has been found to be effective in treating S. haematobium infections compared with metrifonate and more effective in treating S. mansoni infection when compared with oxamniquine. Because the drug is effective even when treating advanced hepatosplenic schistosomiasis, with few side effects, praziquantel is currently the drug of choice for the treatment of any kind of schistosomiasis. The only limitation is the cost which restricts its use in many developing countries. While effective, safe drugs for mass chemotherapy are being developed, the problem of therapeutic failure and drug resistance is being reported from certain developing countries. Under these circumstances, alternative drugs must be resorted to. Mass treatment, a crucial goal in the eventual control of schistosomiasis, awaits a well-tolerated and nontoxic drug that will ultimately prove to be effective where cure is definite. Until such a time, while eradication of the disease is a near impossibility, reducing the intensity of infection can ultimately reduce morbidity and even mortality.(ABSTRACT TRUNCATED AT 400 WORDS)
Collapse
|