PURPOSE: To review the clinical features and natural courses of cold urticaria (ColdU) in a tropical country. METHODS: A retrospective chart review was performed of patients who visited Siriraj Urticaria Clinic, Siriraj Hospital, Bangkok, Thailand, and were diagnosed with ColdU between 2007 and 2018. Data on provocation and threshold tests, clinical courses, and laboratory work-up were analyzed and compared with data reported by studies in temperate countries. RESULTS: Of 1,063 chronic urticaria patients, 27 (2.5%) were diagnosed with ColdU, with a mean age of symptom onset of 34.8 years. Half of the patients had a history of atopy, and 1 (3.7%) had a history of anaphylaxis. All patients were positive to 1 of 3 provocation tests: an ice cube test; TempTest 4.0; or a tray filled with ice, salt and water. Thirteen patients underwent the ice cube test, and all had positive results. TempTest was performed on 15 patients, 8 of whom had positive results, with a mean critical temperature threshold (CTT) of 21.0°C. All of the 7 patients who had a negative TempTest result later produced positive results to the immersion of their hand and forearm in a tray filled with ice, salt, and water. All patients were treated with H1-antihistamines, the vast majority (96.3%) being non-sedating H1-antihistamines. Some (14.8%) needed to be administered oral corticosteroids, ciclosporin, or omalizumab. Six patients (22.2%) were in remission. A Kaplan-Meier survival curve demonstrated 5-year and 10-year remission rates of 13.8% and 42.6%, respectively. CONCLUSIONS: The rate of anaphylaxis in patients with ColdU in a tropical country was lower than those reported by other studies conducted intemperate climates. On the other hand, the number of female patients, mean age at symptom onset, atopy rate, rate of concomitant chronic spontaneous urticaria and mean CTT were higher.
Adrenal Cortex Hormones ; Anaphylaxis ; Climate ; Cyclosporine ; Female ; Forearm ; Hand ; Humans ; Ice ; Immersion ; Omalizumab ; Retrospective Studies ; Thailand ; Tropical Climate ; Urticaria ; Water

Paederus dermatitis is a characteristic irritant contact dermatitis caused by paederin which is a chemical substance released by insects of the genus Paederus. Erythematous vesiculobullous eruption with a burning sensation occur within 24 hours after contact with Paederus. This dermatitis is frequently seen in regions with hot, tropical climates such as Africa and the Middle East. There have been a few reports of Paederus dermatitis in Korea. We recently had a patient with Paederus dermatitis who traveled to Kenya. We would like to highlight an awareness of this peculiar dermatitis due to the increasing numbers of travelers visiting tropical countries.
Africa ; Burns ; Dermatitis* ; Dermatitis, Contact ; Humans ; Insects ; Kenya ; Korea ; Middle East ; Sensation ; Tropical Climate

Representative pioneer tree root systems in the subtropical area of South China were examined with regard to their structure, underground stratification and biomass distribution. Excavation of skeleton roots and observation of fine roots of seven species including the Euphorbiaceae, Theaceae, Melastomataceae, Lauraceae and Fagaceae families was carried out. The results showed that: (1) Pioneer tree roots in the first stage of natural succession were of two types, one characterized by taproot system with bulky plagiotropic branches; the other characterized by flat root system with several tabular roots. The late mesophilous tree roots were characterized by one obvious taproot and tactic braches roots up and down. Shrub species roots were characterized by heart fibrous root type featured both by horizontally and transversally growing branches. Root shapes varied in different dominant species at different stages of succession. (2) Roots of the different species varied in the external features-color, periderm and structure of freshly cut slash. (3) In a set of successional stages the biomass of tree roots increased linearly with the age of growth. During monsoon, the total root biomass amounted to 115.70 t/ha in the evergreen broad-leaved forest; 50.61 t/ha in needle and broad-leaved mixed forest dominated by coniferous forest; and 64.20 t/ha in broad-and needle-leaved mixed forest dominated by broad-leaved heliophytes, and are comparable to the underground biomass observed in similar tropical forests. This is the first report about roots characteristics of forest in the lower sub-tropical area of Dinghushan, Guangdong, China.
Biomass ; China ; Magnoliopsida ; growth & development ; Plant Roots ; growth & development ; Time Factors ; Trees ; growth & development ; Tropical Climate

Strongyloides stercoralis is an intestinal nematode that infects a large portion of the world's population, especially in tropical climates, where the warm, moist soil offers an environment suited to the development of the larvae. In immuno-compromised hosts, receiving corticosteroids, immunosuppressive drugs or radiotherapy, especially in those with AIDS, large numbers of invasive strongyloides larvae can disseminate widely, which can be fatal. In Korea, several cases of strongyloides hyperinfection have been reported since 1959, and a case of strongyloides hyperinfection, accompanied with metastatic stomach cancer, was reported recently. We experienced a case of strongyloides infection, accompanied with early gastric cancer, and also suffering from bronchial asthma. The patient was treated with albendazole, 200 mg, twice-a-day for 3 days, 1 month after a radical gastric cancer operation. Thereafter, the respiratory symptoms of the patient, including asthmatic attacks, improved.
Adrenal Cortex Hormones ; Albendazole ; Asthma ; Humans ; Korea ; Larva ; Radiotherapy ; Soil ; Stomach Neoplasms* ; Strongyloides ; Strongyloides stercoralis* ; Tropical Climate

Introduction of double-stranded RNA (dsRNA) into some cells or organisms results in degradation of its homologous mRNA, a process called RNA interference (RNAi). The dsRNAs are processed into short interfering RNAs (siRNAs) that subsequently bind to the RNA-induced silencing complex (RISC), causing degradation of target mRNAs. Because of this sequence-specific ability to silence target genes, RNAi has been extensively used to study gene functions and has the potential to control disease pathogens or vectors. With this promise of RNAi to control pathogens and vectors, this paper reviews the current status of RNAi in protozoans, animal parasitic helminths and disease-transmitting vectors, such as insects. Many pathogens and vectors cause severe parasitic diseases in tropical regions and it is difficult to control once the host has been invaded. Intracellularly, RNAi can be highly effective in impeding parasitic development and proliferation within the host. To fully realize its potential as a means to control tropical diseases, appropriate delivery methods for RNAi should be developed, and possible off-target effects should be minimized for specific gene suppression. RNAi can also be utilized to reduce vector competence to interfere with disease transmission, as genes critical for pathogenesis of tropical diseases are knockdowned via RNAi.
Animals ; Communicable Diseases/*genetics/*parasitology ; Helminths/*genetics/metabolism ; Humans ; Insect Vectors/*genetics/metabolism ; Protozoa/*genetics/physiology ; *RNA Interference ; *Tropical Climate

Introduction of double-stranded RNA (dsRNA) into some cells or organisms results in degradation of its homologous mRNA, a process called RNA interference (RNAi). The dsRNAs are processed into short interfering RNAs (siRNAs) that subsequently bind to the RNA-induced silencing complex (RISC), causing degradation of target mRNAs. Because of this sequence-specific ability to silence target genes, RNAi has been extensively used to study gene functions and has the potential to control disease pathogens or vectors. With this promise of RNAi to control pathogens and vectors, this paper reviews the current status of RNAi in protozoans, animal parasitic helminths and disease-transmitting vectors, such as insects. Many pathogens and vectors cause severe parasitic diseases in tropical regions and it is difficult to control once the host has been invaded. Intracellularly, RNAi can be highly effective in impeding parasitic development and proliferation within the host. To fully realize its potential as a means to control tropical diseases, appropriate delivery methods for RNAi should be developed, and possible off-target effects should be minimized for specific gene suppression. RNAi can also be utilized to reduce vector competence to interfere with disease transmission, as genes critical for pathogenesis of tropical diseases are knockdowned via RNAi.
Animals ; Communicable Diseases/*genetics/*parasitology ; Helminths/*genetics/metabolism ; Humans ; Insect Vectors/*genetics/metabolism ; Protozoa/*genetics/physiology ; *RNA Interference ; *Tropical Climate

Tropical inhabitants are able to tolerate heat through permanent residence in hot and often humid tropical climates. The goal of this study was to clarify the peripheral mechanisms involved in thermal sweating pre and post exposure (heat-acclimatization over 10 days) by studying the sweating responses to acetylcholine (ACh), a primary neurotransmitter of sudomotor activity, in healthy subjects (n=12). Ten percent ACh was administered on the inner forearm skin for iontophoresis. Quantitative sudomotor axon reflex testing, after iontophoresis (2 mA for 5 min) with ACH, was performed to determine directly activated (DIR) and axon reflex-mediated (AXR) sweating during ACh iontophoresis. The sweat rate, activated sweat gland density, sweat gland output per single gland activated, as well as oral and skin temperature changes were measured. The post exposure activity had a short onset time (p<0.01), higher active sweat rate [(AXR (p<0.001) and DIR (p<0.001)], higher sweat output per gland (p<0.001) and higher transepidermal water loss (p<0.001) compared to the pre-exposure measurements. The activated sweat rate in the sudomotor activity increased the output for post-exposure compared to the pre-exposure measurements. The results suggested that post-exposure activity showed a higher active sweat gland output due to the combination of a higher AXR (DIR) sweat rate and a shorter onset time. Therefore, higher sudomotor responses to ACh receptors indicate accelerated sympathetic nerve responsiveness to ACh sensitivity by exposure to environmental conditions.
Acetylcholine ; Axons ; Forearm ; Hot Temperature ; Iontophoresis ; Neurotransmitter Agents ; Receptors, Cholinergic ; Reflex ; Skin ; Skin Temperature ; Sweat ; Sweat Glands ; Sweating ; Tropical Climate

Dengue fever is caused by the dengue virus which belongs to the flaviviridae family and is transmitted by mosquitos. It occurs in the tropical climates of central and south america, asia, and africa and is considered one of the most important arthropod-borne viral diseases as regards morbidity and mortality, especially due to its hemorrhagic forms, dengue hemorrhagic fever and dengue shock syndrome. We report a case of dengue fever which presented with typical systemic symptoms and signs such as fever, headache, nausea and characteristic erythroderma (white islands in a sea of red) on travelling Bangladesh.
Africa ; Asia ; Bangladesh ; Culicidae ; Dengue Virus ; Dengue* ; Dermatitis, Exfoliative ; Fever ; Flaviviridae ; Headache ; Humans ; Islands ; Mortality ; Nausea ; Severe Dengue ; South America ; Tropical Climate ; Virus Diseases

Strongylodiasis is universal in distribution but is most abundant in countries with a tropical climate. Although infestation by Strongyloides stercoralis is usually limited to the intestines, dessemination of this helminth in debilitated host can be lead to death with various clinical disorders. characterized by profound malabsorption, diarrhea, electrolyte imbalance, gram negative or opportunistic fungal sepsis, coma and death. Cell-mediated immunity contributing significantly to the control of helminthic infections, may be suppressed by carcinoma, immunosuppressive chemotherapy and use of corticosteroids. Diagnosis of Strongyloidiasis is achieved by an examination of samples of feces, duodenal aspirates and sputum of patients for Strongyloides stercoralis. Treatment of strongyloidiasis is twofold : correction of the immunosuppressive state by withdrawal of immunosuppressive drug, if possible, and vigorous treatment with thiabendazole. Testing for strongyloidiasis is especially recommanded before treating a patients should be monitored for infection by Strongyloides stercoralis and other opportunistic infection. We are reporting a case patient with Strongyloides stercoralis hyperinfection and pulmonary tuberculosis who had been. used corticosteroid for persisting polyarthritis.
Adrenal Cortex Hormones ; Arthritis ; Coma ; Diagnosis ; Diarrhea ; Drug Therapy ; Feces ; Helminths ; Humans ; Immunity, Cellular ; Intestines ; Opportunistic Infections ; Sepsis ; Sputum ; Strongyloides stercoralis* ; Strongyloides* ; Strongyloidiasis ; Thiabendazole ; Tropical Climate ; Tuberculosis, Pulmonary

Strongyloides stercoralis is distinguished by a capacity, unusual among helminths to replicate within the human host, thereby permitting on going cycle of autoinfection due to internal production of internal larvae. It has a worldwide distribution but is much more common in tropical climates where the warm, moist soil offers an environment suited to the development of the larvae. In immunocompromised hosts who receiving corticosteroids, immunosupressive drugs, or radiotherapy in these with AIDS, large numbers of invasive strongyloides larvae can disseminate widely and be fatal. The presents case is a 76 year-old-woman presenting with vomiting and epigastric pain. The patient had a long history of adminstration of steroid and alcohol. A gastrofibroscopic biopsy and stool examination revealed rhabditoid larvae. The patient seems to have suffered from autoinfection with S. stercoralis. We report this case with the review of literatures.
Adrenal Cortex Hormones ; Alcoholics* ; Biopsy ; Helminths ; Humans ; Immunocompromised Host ; Larva ; Liver Diseases, Alcoholic* ; Radiotherapy ; Soil ; Strongyloides stercoralis* ; Strongyloides* ; Tropical Climate ; Vomiting