Polylactic Acid-Based Biomaterials in Wound Healing: A Systematic Review.

OBJECTIVE: To examine (1) the effectiveness of polylactic acid (PLA)-based biomaterials in wound healing, (2) their effects on wound infection prevention, and (3) their safety compared with existing biomaterials. DATA SOURCES: Data sources included PubMed, MEDLINE, Cochrane Library, CINAHL (Cumulative Index to Nursing and Allied Health Literature), CNKI (China National Knowledge Infrastructure), WEIPU, and WANFANG databases. STUDY SELECTION: Investigators included 14 studies discussing the effects of PLA-based biomaterials in cutaneous wound healing published from 2000 to 2021. DATA EXTRACTION: Authors extracted the following information from the selected studies: general information, study type, type of wound, PLA-based biomaterials and techniques, study period, outcome measures, and results. DATA SYNTHESIS: Polylactic acid-based biomaterials may promote wound healing through wound area repair, collagen deposition, angiogenesis, and cell activities, which are related to the good biocompatibility, biodegradability, and moisture management properties of PLA. A proper product structure may also help. Both the native PLA materials and PLA blends seem to be antibacterial, although more evidence is needed for the native PLA products. Because there was no severe adverse event or obvious cytotoxicity observed in the included studies, PLA-based biomaterials are likely safe. CONCLUSIONS: Polylactic acid-based biomaterials may be good wound dressing materials, although more evidence is needed to support their broader application in wound care.

Association between periodontitis treatment and dementia in Taiwanese adults.

BACKGROUND: The chronic systemic inflammatory response in periodontitis may be a potential risk factor for dementia, especially in adults. This study determined the association between periodontal treatment and dementia in adults and evaluated the effect of regular scaling treatment on the risk of dementia in this population. METHODS: This case-control study identified 18,930 patients with a dementia-related diagnosis from the Taiwan National Health Insurance Research Database. Scaling and periodontal emergency treatments were evaluated after 1 year and 3 years. Using multivariable logistic regression analysis to evaluate the association between periodontal emergency treatment and dementia risk. RESULTS: The results showed that scaling treatment rates were lower in the dementia cohort than the non-dementia cohort after 1 and 3 years. Patients who received periodontal emergency treatment within 3 years had a significantly increased risk of dementia. Furthermore, patients with periodontitis who did not receive scaling treatment within 3 years had a higher risk of dementia than patients without periodontitis (OR, 1.22; 95% CI, 1.10-1.35). CONCLUSION: This study demonstrated that periodontitis and dementia are associated, and that periodontitis is a risk factor for dementia in adults. The risk of dementia was dependent on the periodontal health status of adults, and our findings suggest that regular scaling can reduce the incidence of dementia in adults. Therefore, regular and routine scaling treatment is suggested for adults.

Microplastic concentrations in river water and bed sediments in a tropical river: implications for water quality monitoring.

Recent increase in awareness of the extent of microplastic contamination in marine and freshwater systems has heightened concerns over the ecological and human health risks of this ubiquitous material. Assessing risks posed by microplastic in freshwater systems requires sampling to establish contamination levels, but standard sampling protocols have yet to be established. An important question is whether sampling and assessment should focus on microplastic concentrations in the water or the amount deposited on the bed. On three dates, five replicated water and bed sediment samples were collected from each of the eight sites along the upper reach of the Semenyih River, Malaysia. Microplastics were found in all 160 samples, with mean concentrations of 3.12 ± 2.49 particles/L in river water and 6027.39 ± 16,585.87 particles/m2 deposited on the surface of riverbed sediments. Fibres were the dominant type of microplastic in all samples, but fragments made up a greater proportion of the material on the bed than in the water. Within-site variability in microplastic abundance was high for both water and bed sediments, and very often greater than between-site variability. Patterns suggest that microplastic accumulation on the bed is spatially variable, and single samples are therefore inadequate for assessing bed contamination levels at a site. Sites with the highest mean concentrations in samples of water were not those with the highest concentrations on the bed, indicating that monitoring based only on water samples may not provide a good picture of either relative or absolute bed contamination levels, nor the risks posed to benthic organisms.

Relative contributions of different local sources to riverborne microplastic in a mixed landuse area within a tropical catchment.

Information on the relative contributions of microplastics coming from different sources is important to help prioritise measures to reduce river contamination levels and limit human and ecological health risks. This paper reports on work which aimed to quantitatively assess the relative concentrations and types of microplastic delivered from differed sources to a second order river. The study was undertaken in a mixed landuse area within a rapidly urbanising catchment in Malaysia. Over a six-week period, water samples were collected from road culverts and drains in residential and industrial areas across the area to assess microplastic concentrations, while inputs from atmospheric deposition and wastewater treatment plants (WWTPs) were also quantified. Microplastic fibres and fragments were the dominant material in all sources, with the majority consisting of styrene-butadiene rubber and nylon. Culverts draining main roads were the main contributor to riverborne microplastic, delivering 42.20 ± 35.29 particles/L directly to the river channel. Road inputs were up to seven times greater than those from residential (8.53 ± 9.91 particles/L) and industrial (5.67 ± 4.88 particles/L) areas. The five WWTPs had removal efficiencies of between 30.95 ± 5.51% and 69.94 ± 22.17%, with their outflows delivering microplastics to the river in concentrations similar to those in uncontrolled residential and industrial drains. Atmospheric deposition across the study area was estimated to be 76.07 ± 32.85 particles/m2/day (=8.35 ± 5.11 particles/L). Mitigation strategies in the study area should focus on improving management of water draining roads, and re-routing discharges from domestic and industrial areas to WWTPs rather than allowing them to flow directly to the river. The low efficiencies of some of the WWTPs are not unusual, and indicate the need for additional water treatment to deal with microplastic present in wastewater.

Impact of mucosal inflammation on oral simian immunodeficiency virus transmission.

Mucosal tissues are the primary route of transmission for most respiratory and sexually transmitted diseases, including human immunodeficiency virus (HIV). There is epidemiological evidence that genital mucosal inflammation leads to enhanced HIV type 1 (HIV-1) transmission. The objective of this study was to assess the influence of periodontal inflammation on oral HIV transmission using a nonhuman primate model of teeth ligature-induced periodontitis. Simian immunodeficiency virus (SIV) was nontraumatically applied to the gingiva after moderate gingivitis was identified through clinical and immunologic analyses (presence of inflammatory cytokines). Overall oral SIV infection rates were similar in the gingivitis-induced and control groups (5 infections following 12 SIV administrations for each), although more macaques were infected with multiple viral variants in the gingivitis group. SIV infection also affected the levels of antiviral and inflammatory cytokines in the gingival crevicular fluid, and a synergistic effect was observed, with alpha interferon and interferon-inducible protein 10 undergoing significant elevations following SIV infection in macaques with gingivitis compared to controls. These increases in antiviral and inflammatory immune modulators in the SIV-infected gingivitis macaques could also be observed in blood plasma, although the effects at both compartments were generally restricted to the acute phase of the infection. In conclusion, while moderate gingivitis was not associated with increased susceptibility to oral SIV infection, it resulted in elevated levels of cytokines in the oral mucosa and plasma of the SIV-infected macaques. These findings suggest a synergy between mucosal inflammation and SIV infection, creating an immune milieu that impacts the early stages of the SIV infection with potential implications for long-term pathogenesis.

The Impact of the COVID-19 Pandemic on Orthodontic Adult Patients' Characteristics and Decision on Orthodontic Appliance.

Purpose: There is an overall paucity of data examining the specific details of orthodontic patients' patterns or orthodontic service disruptions possibly influenced by COVID-19 pandemic. Therefore, this study aimed to explore the impact of the COVID-19 pandemic on orthodontic clinic disruption regarding the change in adult patients' characteristics and decisions of orthodontic treatment devices. Patients and Methods: A retrospective sample of 311 patients receiving orthodontic treatment from 2018 to 2022 were collected and divided into two groups: before (n = 167) and during (n = 144) the COVID-19 pandemic. Demographics, dental indices, the index of complexity outcome and need (ICON), and the degree of treatment difficulty were analyzed. Results: There were fewer students among patients during the COVID-19 pandemic than before (24.5% versus 35.9%, P = 0.036). Compared with patients before the pandemic, more patients selected ceramic brackets or Invisalign during the pandemic (P = 0.022). There were higher percentage of class I dental malocclusions among patients during than before the COVID-19 pandemic (P = 0.044). Moreover, the ICON score and the score of the degree of treatment difficulty were both significantly lower for patients during than before the COVID-19 pandemic (63.9±14.0 versus 58.3±15.3, P=0.001 and 7.4±2.6 versus 6.8±2.6, P=0.049, respectively). Conclusion: The COVID-19 pandemic influenced the characteristics and decisions of orthodontic patients. Those who still came to the orthodontic clinic despite the COVID-19 outbreak may have been those with less malocclusion severity and treatment difficulty. Besides, during the time of covid-19 pandemic, more patients chose ceramic bracket and Invisalign as their orthodontic treatment device rather than conventional or self-ligating metal brackets.

Emergence, circulation, and spatiotemporal phylogenetic analysis of coxsackievirus a6- and coxsackievirus a10-associated hand, foot, and mouth disease infections from 2008 to 2012 in Shenzhen, China.

Sporadic hand, foot, and mouth disease (HFMD) outbreaks and other infectious diseases in recent years have frequently been associated with certain human enterovirus (HEV) serotypes. This study explored the prevalences and genetic characteristics of non-HEV71 and non-coxsackievirus A16 (CV-A16) human enterovirus-associated HFMD infections in Shenzhen, China. A total of 2,411 clinical stool specimens were collected from hospital-based surveillance for HFMD from 2008 to 2012. The detection of HEV was performed by real-time reverse transcription-PCR (RT-PCR) and RT-seminested PCR, and spatiotemporal phylogenetic analysis was performed based on the VP1 genes. A total of 1,803 (74.8%) strains comprising 28 different serotypes were detected. In the past 5 years, the predominant serotypes were HEV71 (60.0%), followed by CV-A16 (21.2%) and two uncommon serotypes, CV-A6 (13.0%) and CV-A10 (3.3%). However, CV-A6 replaced CV-A16 as the second most common serotype between 2010 and 2012. As an emerging pathogen, CV-A6 became as common a causative agent of HFMD as HEV71 in Shenzhen in 2012. Phylogenetic analysis revealed that little variation occurred in the Chinese HEV71 and CV-A16 strains. The genetic characteristics of the Chinese CV-A6 and CV-A10 strains displayed geographic differences. The CV-A6 and CV-A10 strains circulating in Shenzhen likely originated in Europe. It was found that human enteroviruses have a high mutation rate due to evolutionary pressure and frequent recombination (3.2 × 10(-3) to 6.4 ×10(-3) substitutions per site per year for HEV71, CV-A6, CV-A16, and CV-A10). Since certain serotypes are potential threats to the public health, this study provides further insights into the significance of the epidemiological surveillance of HFMD.

Characteristics and Dental Indices of Orthodontic Patients Using Aligners or Brackets.

Background. Clear aligners have become a treatment alternative to metal brackets in recent years due to the advantages of aesthetics, comfort, and oral health improvement. Nevertheless, few studies have analyzed the clinical characteristics and dental indices of orthodontic patients using aligners or brackets. Methods. A total of 170 patients received orthodontic treatment at Chang Gung Memorial Hospital in 2021. Patients were stratified by types of treatment (Invisalign® clear aligner (n = 60) or metal bracket (n = 110). Results: Patients were aged 26.1 ± 7.2 years, and most were female (75.0%). The Invisalign® group was older than the bracket group (p = 0.003). The skeletal relationships were mainly Class I (49.4%), followed by Class II (30.0%) and Class III (20.6%). The molar relationships were primarily Class I (38.8%), followed by Class II (37.1%) and Class III (24.1%). The decayed, missing, and filled tooth (DMFT) index was 9.9 ± 6.0, including 2.1 ± 2.9 for decayed teeth, 0.5 ± 1.1 for missing teeth, and 7.3 ± 4.3 for filled teeth. There were no significant differences in the DMFT index or skeletal and molar relationships between the groups (p > 0.05). The index of complexity outcome and need (ICON) was 56.8 ± 13.5, and the score was lower in the Invisalign® group than in the bracket group (p = 0.002). Among the variables included in the ICON assessment, only the aesthetic variable was lower in the Invisalign® group than in the bracket group (p < 0.001). The Frankfort-mandibular plane angle was 27.9 ± 5.1 degrees. Finally, the E-line of the lower lip was lower in the Invisalign® group than in the bracket group (1.5 ± 2.4 versus 2.8 ± 3.1, p = 0.005). Conclusions. Older patients showed a greater intention to choose Invisalign® treatment for improving the appearance of their teeth than younger patients, who chose metal bracket treatment. The demand for Invisalign® aligner treatment for aesthetic reasons was substantial. A soft tissue profile with more protrusive lower lips and a greater need for orthodontic treatment was found in the bracket group.

The relationship of the occurrence between three-rooted deciduous mandibular second molars and three-rooted permanent mandibular first molars in children.

BACKGROUND/PURPOSE: This study aimed to determine the correlation between the occurrence of three-rooted deciduous mandibular second molars and three-rooted permanent mandibular first molars in children. MATERIALS AND METHODS: Orthopantograms (n = 977) obtained from August 2008 to December 2010 were retrospectively screened and examined. Among the 977 orthopantograms, those of 591 participants (314 boys and 277 girls; mean age, 8.7 years) with bilateral deciduous mandibular second molars and permanent mandibular first molars were studied. The gender predilection and prevalence of three-rooted mandibular molars were assessed, and the pattern of concurrence was investigated. RESULTS: The prevalence of three roots were 28.4% and 27.6% in the deciduous mandibular second molars and permanent mandibular first molars, respectively. Bilateral occurrence of three-rooted mandibular molars was almost 60% for both deciduous and permanent molars. There was a significantly greater prevalence of three-rooted mandibular molars on the right side of the mandible than that on the left side. CONCLUSION: Deciduous and permanent molars show a similar prevalence of three roots. The presence of three-rooted deciduous mandibular second molar can strongly predict the possibility of three roots in permanent mandibular first molar.

Spatio-temporal variation of microplastic along a rural to urban transition in a tropical river.

Microplastic pollution is widely recognised as a global issue, posing risks to natural ecosystems and human health. The combination of rapid industrial and urban development and relatively limited environmental regulation in many tropical countries may increase the amount of microplastic entering rivers, but basic data on contamination levels are lacking. This is especially the case in tropical South East Asian countries. In this paper, the abundance, composition and spatio-temporal variation of microplastic in the Langat River, Malaysia, were assessed, and the relationship between microplastic concentration and river discharge was investigated. Water samples were collected over a 12-month period from 8 sampling sites on the Langat, extending from forested to heavily urbanised and industrial areas. All 508 water samples collected over this period contained microplastic; mean concentration across all sites and times was 4.39 particles/L but extended up to 90.00 particles/L in some urban tributaries. Most microplastics were secondary in origin, and dominated by fibres. Microplastic counts correlated directly with river discharge, and counts increased and decreased in response to changes in flow. A time-integrated assessment of the microplastic load conveyed by the Langat suggested that the river is typically (50 % of the time) delivering around 5 billion particles per day to the ocean. The positive correlation between the concentration of microplastics and suspended sediments in the Langat suggested that continuously logging turbidity sensors could be used to provide better estimates of microplastic loads and improve assessment of human and ecological health risks.

Microplastic pollution in freshwater systems in Southeast Asia: contamination levels, sources, and ecological impacts.

Plastics are synthetic polymers known for their outstanding durability and versatility, and have replaced traditional materials in many applications. Unfortunately, their unique traits ensure that they pose a major threat to the environment. While literature on freshwater microplastic contamination has grown over the recent years, research undertaken in rapidly developing countries, where plastic production and use are increasing dramatically, has lagged behind that in other parts of the world. In the South East Asia (SEA) region, basic information on levels of contamination is very limited and, as a consequence, the risk to human and ecological health remains hard to assess. This review synthesises what is currently known about microplastic contamination of freshwater ecosystems in SEA, with a particular focus on Malaysia. The review 1) summarises published studies that have assessed levels of contamination in freshwater systems in SEA, 2) discusses key sources and transport pathways of microplastic in freshwaters, 3) outlines what is known of the impacts of microplastic on freshwater organisms, and 4) identifies key knowledge gaps related to our understanding of the transport, fate and effects of microplastic.

Environmental Cadmium Exposure and Dental Indices in Orthodontic Patients.

BACKGROUND: Previous studies have shown that environmental cadmium exposure could disrupt salivary gland function and is associated with dental caries and reduced bone density. Therefore, this cross-sectional study attempted to determine whether tooth decay with tooth loss following cadmium exposure is associated with some dental or skeletal traits such as malocclusions, sagittal skeletal pattern, and tooth decay. METHODS: Between August 2019 and June 2020, 60 orthodontic patients with no history of previous orthodontics, functional appliances, or surgical treatment were examined. The patients were stratified into two groups according to their urine cadmium concentrations: high (>1.06 µg/g creatinine, n = 28) or low (<1.06 µg/g creatinine, n = 32). RESULTS: The patients were 25.07 ± 4.33 years old, and most were female (female/male: 51/9 or 85%). The skeletal relationship was mainly Class I (48.3%), followed by Class II (35.0%) and Class III (16.7%). Class I molar relationships were found in 46.7% of these patients, Class II molar relationships were found in 15%, and Class III molar relationships were found in 38.3%. The mean decayed, missing, and filled surface (DMFS) score was 8.05 ± 5.54, including 2.03 ± 3.11 for the decayed index, 0.58 ± 1.17 for the missing index, and 5.52 ± 3.92 for the filled index. The mean index of complexity outcome and need (ICON) score was 53.35 ± 9.01. The facial patterns of these patients were within the average low margin (26.65 ± 5.53 for Frankfort-mandibular plane angle (FMA)). There were no significant differences in the above-mentioned dental indices between patients with high urine cadmium concentrations and those with low urine cadmium concentrations. Patients were further stratified into low (<27, n = 34), average (27-34, n = 23), and high (>34, n = 3) FMA groups. There were no statistically significant differences in the urine cadmium concentration among the three groups. Nevertheless, a marginally significant p-value of 0.05 for urine cadmium concentration was noted between patients with low FMA and patients with high FMA. CONCLUSION: This analysis found no association between environmental cadmium exposure and dental indices in our orthodontic patients.

Treatment of a severely ankylosed central incisor and a missing lateral incisor by distraction osteogenesis and orthodontic treatment.

Ankylosis is the fusion between the mineralized root surface and the alveolar bone. Tooth trauma is a common etiologic cause of ankylosis. In young patients, the ankylosed teeth fail to erupt along with the remaining alveolar process during vertical facial growth, resulting in submerged teeth and defects in the alveolar process. Extraction of the ankylosed teeth followed by prosthetic replacement is a common option for treatment. This case report presents the treatment of a woman with an anterior open bite and an ankylosed central incisor due to replantation of a traumatized tooth. We treated this ankylosed central incisor with subapical osteotomy and distraction osteogenesis for better tissue regeneration. After active orthodontic treatment and prosthetic restoration, her open bite was corrected, and she had a harmonious smile line.

Accuracy of implant placement with a computer-aided fabricated surgical template with guided parallel pins: A pilot study.

BACKGROUND: A precise positioning for dental implant placement is important for further prosthesis fabrication and maintenance. Computer-aided surgery has been developed to transfer digitally planned implant positioning to the patient over the past decades. This study aimed to evaluate the accuracy of a computer-aided laboratory-fabricated surgical template. A further objective was to compare the accuracy between in vivo and in vitro groups. METHODS: A total of 20 implants were placed in the posterior tooth region through the aid of surgical templates on 17 partially edentulous patients in the in vivo group. The surgical template was fabricated in laboratory after virtual implant planning was completed using computer software. In the in vitro group, the same procedures were performed on the models without placing fixture with the same templates used in surgery. Deviations of the implant access at the implant platform level and apical region, as well as the angle deviations between the virtual planning data and the surgical results, were measured using a follow-up Cone Beam Computerized Tomography (CBCT) investigation, and image fusion with planning data. RESULT: The median deviation at platform level, apex and angulation was 0.95 mm (0.3-1.3 mm),1.35 mm (0.1-3.6 mm) and 3.92° (0.44-11.66°) respectively in the in vivo group; and 0.4 mm (0-1.0 mm), 0.65 mm (0.1-1.9 mm), 2.16° (0.17-6.91) respectively in the in vitro group. The in vitro group displayed significantly less deviation (p < 0.05). CONCLUSION: The data from this study shows that computer-aided laboratory-fabricated template may be a reliable tool for implant placement. However, the clinical conditions seem to affect the accuracy of the template.

Effects of non-thermal plasma on sandblasted titanium dental implants in beagle dogs.

BACKGROUND: In this study, we investigated the effects of treating dental implants made from titanium with argon based non-thermal plasma, immediately before insertion on implant stability and bone formation. Biodegradable sandblasting and acid etching had been previously used to modify the surface of the implants. METHODS: To obtain data for 4-time points in triplicate with references, a total of 36 dental implants were divided into 2 groups; 18 implants served as the experimental group and received a spray containing non-thermal plasma, while the other 18 implants served as controls. Two treated and two untreated implants were each inserted in the jaws of 9 beagle dogs. After periods of 4, 8, and 12 weeks, the Implant Stability Quotient scores were determined and histometric values obtained. RESULTS: Plasma spray treatment increased the healing time slightly during the early recovery period (4th to 8th week, p = 0.1595 and 0.1041, respectively), but was not profoundly effective in the later recovery stage (12th week, p = 0.4942). Both non-decalcified histometric measurements and bone growth analysis showed no statistically significant differences between the plasma spray group and the controls at 4, 8, and 12 weeks. CONCLUSION: Non-thermal plasma did not enhance the stability of the implants nor did it increase bone formation in our animal models.

Orthognathic Surgery with Simultaneous Autologous Fat Transfer for Correction of Facial Asymmetry.

BACKGROUND: Most patients treated with orthognathic surgery for facial asymmetry would value improvement in residual soft-tissue asymmetry. Autologous fat transfer is widely used to augment facial soft tissue. The authors assessed the effect of combining orthognathic surgery with autologous fat transfer for treating patients with facial asymmetry. METHODS: In this retrospective study, 15 consecutive adults underwent combined orthognathic surgery and autologous fat transfer between January of 2013 and December of 2015. Lower facial profile symmetry was assessed using postoperative standard frontal photographs. RESULTS: Lower facial symmetry was much improved by combining orthognathic surgery and autologous fat injection. CONCLUSION: The combined use of orthognathic surgery and autologous fat transfer is a promising technique for improving facial symmetry in patients with facial asymmetry. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Molecular identification and analysis of human enteroviruses isolated from healthy children in Shenzhen, China from 2010 to 2011.

OBJECTIVE: To determine the prevalence and distribution of human enteroviruses (HEVs) among healthy children in Shenzhen, China. METHOD: Clinical specimens were obtained from 320 healthy children under 5 years old in Shenzhen, China from 2010 to 2011. The specimens were evaluated using real-time PCR and cell cultures. The positive specimens were further tested using reverse transcription-seminested PCR (RT-snPCR). Molecular typing and phylogenetic analysis were based on the sequence determined. RESULTS: Among the 320 samples, 34 were tested positive for HEVs (10.6%) and 22 different serotypes were identified using RT-snPCR. PV1 and PV2 were also detected. The predominant serotype observed was EV71 (17.6%), followed by CV-B4 (14.7%). HEV-B was detected most frequently, with an overall prevalence of 47.1%. HEV-A and HEV-C were found in 32.3% and 20.6% of the samples, respectively. No HEV-D was identified. Molecular phylogeny indicated that all EV71 strains were of C4 genotype. CONCLUSION: Although a variety of HEVs was detected in healthy children, HEV-B was relatively more prevalent than other HEV species. Considering HEV-A is more prevalent than HEV-B among patients with hand-foot-mouth disease, additional long-term surveillance of HEV is warranted in both asymptomatic and symptomatic populations.

Detection of SARS-associated coronavirus in throat wash and saliva in early diagnosis.

The severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is thought to be transmitted primarily through dispersal of droplets, but little is known about the load of SARS-CoV in oral droplets. We examined oral specimens, including throat wash and saliva, and found large amounts of SARS-CoV RNA in both throat wash (9.58 x 10(2) to 5.93 x 10(6) copies/mL) and saliva (7.08 x 10(3) to 6.38 x 10(8) copies/mL) from all specimens of 17 consecutive probable SARS case-patients, supporting the possibility of transmission through oral droplets. Immunofluorescence study showed replication of SARS-CoV in the cells derived from throat wash, demonstrating the possibility of developing a convenient antigen detection assay. This finding, with the high detection rate a median of 4 days after disease onset and before the development of lung lesions in four patients, suggests that throat wash and saliva should be included in sample collection guidelines for SARS diagnosis.