Healthcare utilisation and cost expenditures for pneumonia in individuals with diabetes mellitus in the USA.

Pneumonia is one of the leading causes of hospitalisations among adults in the USA. Individuals with diabetes mellitus (DM) have been associated with increased risk for pneumonia and complications including death. The objectives of this study were to (1) compare the prevalence and healthcare utilisation patterns for pneumonia in individuals with and without DM, and (2) identify risk factors for pneumonia in those with DM. We performed a retrospective, cross-sectional analysis of the US adult population using Medical Expenditure Panel Surveys (MEPS) data from 2014. Overall, the data represented 24 million individuals with DM and 218 million without DM in the USA. The population-based rate for a pneumonia event was 34 per 1000 persons for individuals with DM and 19 per 1000 persons without DM. Compared to the non-DM group, individuals with DM were treated 1.8x, 2.6x and 1.4x more in the ED, hospital and outpatient, respectively. Furthermore, the average cost per pneumonia event was significantly higher among individuals with DM compared to non-DM in the inpatient setting ($11 931 vs. $7751; P < 0.001). Among individuals with DM, female sex, DM complications, smokers and administration of pneumococcal vaccines were significant factors associated with a pneumonia event.

Predictors of community-associated Staphylococcus aureus, methicillin-resistant and methicillin-susceptible Staphylococcus aureus skin and soft tissue infections in primary-care settings.

Skin and soft tissue infections (SSTIs) due to Staphylococcus aureus have become increasingly common in the outpatient setting; however, risk factors for differentiating methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) SSTIs are needed to better inform antibiotic treatment decisions. We performed a case-case-control study within 14 primary-care clinics in South Texas from 2007 to 2015. Overall, 325 patients [S. aureus SSTI cases (case group 1, n = 175); MRSA SSTI cases (case group 2, n = 115); MSSA SSTI cases (case group 3, n = 60); uninfected control group (control, n = 150)] were evaluated. Each case group was compared to the control group, and then qualitatively contrasted to identify unique risk factors associated with S. aureus, MRSA, and MSSA SSTIs. Overall, prior SSTIs [adjusted odds ratio (aOR) 7·60, 95% confidence interval (CI) 3·31-17·45], male gender (aOR 1·74, 95% CI 1·06-2·85), and absence of healthcare occupation status (aOR 0·14, 95% CI 0·03-0·68) were independently associated with S. aureus SSTIs. The only unique risk factor for community-associated (CA)-MRSA SSTIs was a high body weight (⩾110 kg) (aOR 2·03, 95% CI 1·01-4·09).

How do radiologists evaluate osteonecrosis?

OBJECTIVES: Management of patients with osteonecrosis of the hip remains controversial and challenging. Because the prognosis and treatment are determined in large part by the stage and extent of the disease, it is important to use a reliable and efficient method for evaluation and staging. The objective of this study was to determine how musculoskeletal (MSK) radiologists evaluate osteonecrosis and whether this evaluation is adequate. MATERIALS AND METHODS: A 12-part questionnaire was designed to determine how MSK radiologists evaluate patients with osteonecrosis of the femoral head (ONFH). This was sent to 888 members of the Society of Skeletal Radiology. RESULTS: One hundred and twenty-one members responded to essentially all questions. Patients were evaluated using plain radiographs and MRI. All agreed that it is clinically important to determine the extent of necrosis and joint involvement, and 115 (95 %) stated that this should be part of the radiologists' evaluation. However, only 55 (46 %) said that in practice they used a specific system of classification, and most of these used the Ficat and Arlet classification, which does not indicate the extent of involvement. One hundred and seven (88 %) respondents included a simple visual estimate of the extent of involvement, and a small number added a specific measurement of lesion size. The majority indicated that they were infrequently consulted about which imaging studies should be obtained. CONCLUSIONS: Although radiologists recognize the clinical importance of determining the extent of necrosis and joint involvement in patients with ONFH, in practice the methods used to evaluate these patients often do not accomplish this satisfactorily. The use of an effective classification, which includes both stage and extent of involvement, should be stressed, as it will lead to improved treatment of patients with ON. Physicians who order imaging studies for patients with ON should be encouraged to consult routinely with their radiology colleagues regarding which studies to request, as well as on the interpretation of these studies.

Cell-culture-based immunochromatography for rapid detection of group A human rotaviruses in aquatic environments.

In an effort to detect rapidly and conveniently the infectious waterborne group A human rotaviruses that cause diarrhea in infants and children, the authors developed the first-ever cell-culture-based immunochromatography method. An immunochromatography kit interacted only with the human rotaviruses VP6 antigen, and the cell-culture-based immunochromatography detected group A human rotaviruses with a sensitivity as low as 1.99 TCID50 ml(-1). This detection sensitivity was similar to that of the cytopathic effect-based method. There were no actual differences between the sensitivity of this method and that of the real-time reverse transcription polymerase chain reaction method, which is known as a method with a relatively high sensitivity. Furthermore, while cell culture detection methods, that is total culturable virus assay, can determine only the presence of infectious waterborne viruses, the cell-culture-based immunochromatography is advantageous for the accurate detection of group A human rotaviruses. Compared with the real-time reverse transcription polymerase chain reaction method, the cell-culture-based immunochromatography is advantageous because it requires a relatively simple process that enables easy quality controls and low test costs. Thus, this study proposed a new method for the identification of group A human rotaviruses, and it is suggested that this cell-culture-based immunochromatography may be applied to detect group A human rotaviruses in aquatic environments.

Not all hip arthroplasties are created equal: increased complications and re-admissions after total hip arthroplasty for femoral neck fractures compared with osteoarthritis.

AIMS: Total hip arthroplasty (THA) is gaining popularity as a treatment for displaced femoral neck fractures (FNFs), especially in physiologically younger patients. While THA for osteoarthritis (OA) has demonstrated low complication rates and increased quality of life, results of THA for acute FNF are not as clear. Currently, a THA performed for FNF is included in an institutional arthroplasty bundle without adequate risk adjustment, potentially placing centres participating in fracture care at financial disadvantage. The purpose of this study is to report on perioperative complication rates after THA for FNF compared with elective THA performed for OA of the hip. PATIENTS AND METHODS: The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database between 2008 and 2016 was queried. Patients were identified using the THA Current Procedural Terminology (CPT) code and divided into groups by diagnosis: OA in one and FNF in another. Univariate statistics were performed. Continuous variables were compared between groups using Student's t-test, and the chi-squared test was used to compare categorical variables. Multivariate and propensity-matched logistic regression analyses were performed to control for risk factors of interest. RESULTS: Analyses included 139 635 patients undergoing THA. OA was the indication in 135 013 cases and FNF in 4622 cases. After propensity matching, mortality within 30 days (1.8% vs 0.3%; p < 0.001) and major morbidity (24.2% vs 19%; p < 0.001) were significantly higher among FNF patients. Re-operation (3.7% vs 2.7%; p = 0.014) and re-admission (7.3% vs 5.5%; p = 0.002) were significantly higher among FNF patients. Hip fracture patients had significantly longer operative time and length of stay (LOS), and were significantly less likely to be discharged to their home. Multivariate analyses gave similar results. CONCLUSION: This large database study showed a higher risk of postoperative complications including mortality, major morbidity, re-operation, re-admission, prolonged operative time, increased LOS, and decreased likelihood of discharge home in patients undergoing THA for FNF compared with OA. While THA is a good option for FNF patients, there are increased costs and financial risks to centres with a joint arthroplasty bundle programme participating in fracture care. Cite this article: Bone Joint J 2019;101-B(6 Supple B):84-90.

When are anti-fat attitudes understood as prejudice versus truth? An experimental study of social influence effects.

BACKGROUND/OBJECTIVES: If people who hold anti-fat attitudes believe these attitudes to be true, then anti-prejudice appeals are likely to be unsuccessful, if only because the targets will not see their attitudes as in need of change. The current study examined processes that may lead people to see their anti-fat attitudes as 'truth' or as 'prejudice'. SUBJECTS/METHODS: Participants (N = 482) read anti-fat statements and were then presented with an interpretation of these statements as 'truth' or 'prejudice'. The source of this interpretation was either an (i) in-group or out-group member and (ii) expert or non-expert. Participants' judgements of the statements were expected to vary such that in-group others and experts would exert more influence than would out-group others and non-experts. RESULTS: Participants aligned their own interpretations of an anti-fat statement with those of an expert, but not with those of a non-expert, F(1,466) = 8.97, p < 0.05, ηp 2 = 0.02. The group membership variable had no effect on judgements of 'truth' or 'prejudice' of the anti-fat statement. CONCLUSION: The expressions that people believe constitute anti-fat prejudice versus truth about people described as overweight are influenced by exposure to expert opinion (in this case, by medical doctors). Implications for the success of weight-based anti-prejudice appeals and for healthcare provision are discussed.

'Hot Joints' infection protocol reduces unnecessary post-operative re-admissions following total hip and knee arthroplasty.

AIMS: To evaluate the effectiveness of an institutionally developed algorithm for evaluation and diagnosis of prosthetic joint injection and to determine the impact of this protocol on overall hospital re-admissions.p PATIENTS AND METHODS: We retrospectively evaluated 2685 total hip arthroplasty (THA) and total knee arthroplasty (TKA) patients prior to (1263) and following (1422) the introduction of an infection detection protocol. The protocol used conservative thresholds for C-reactive protein to direct the medical attendant to aspirate the joint. The protocol incorporated a clear set of laboratory and clinical criteria that allowed a patient to be discharged home if all were met. Patients were included if they presented to our emergency department within 120 days post-operatively with concerns for swelling, pain or infection and were excluded if they had an unambiguous infection or if their chief complaint was non-orthopaedic in nature. RESULTS: Concern for infection was the single most common (32%) reason for presentation. A total of 296 patients made an emergency visit and were included following THA or TKA. In the pre-protocol cohort, 11 of 27 patients were formally re-admitted to the hospital with concern for infection but only five (45%) patients had actual infections and received additional treatment. In comparison, in the post-protocol cohort, 11 patients were admitted for suspected infection, nine (82%) of whom were truly infected (p = 0.04). Sensitivity increased from 83% to 100% and specificity increased from 71% to 96%. Implementation of this protocol did not miss any infections. CONCLUSION: A standardised protocol for evaluation of THA and TKA infections significantly reduced unnecessary hospital re-admissions. The protocol was both sensitive and specific and did not compromise quality of care. Cite this article: Bone Joint J 2017;99-B:1603-10.

Patient-specific cutting blocks: Of Unproven Value.

Patient specific instrumentation (PSI) uses advanced imaging of the knee (CT or MRI) to generate individualised cutting blocks aimed to make the procedure of total knee arthroplasty (TKA) more accurate and efficient. However, in this era of healthcare cost consciousness, the value of new technologies needs to be critically evaluated. There have been several comparative studies looking at PSI versus standard instrumentation. Most compare PSI with conventional instrumentation in terms of alignment in the coronal plane, operative time and surgical efficiency, cost effectiveness and short-term outcomes. Several systematic reviews and meta-analyses have also been published. PSI has not been shown to be superior compared with conventional instrumentation in its ability to restore traditional mechanical alignment in primary TKA. Most studies show comparative efficacy and no decrease in the number of outliers in either group. In terms of operative time and efficiency, PSI tended towards decreasing operative time, saving a mean of five minutes per patient (0 to 20). Furthermore, while some cost savings could be realised with less operative time and reduced instrumentation per patient, these savings were overcome by the cost of the CT/MRI and the cutting blocks. Finally, there was no evidence that PSI positively affected clinical outcomes at two days, two months, or two years. Consequently, current evidence does not support routine use of PSI in routine primary TKA.

Which patients need critical care intervention after total joint arthroplasty? : a prospective study of factors associated with the need for intensive care following surgery.

Older patients with multiple medical co-morbidities are increasingly being offered and undergoing total joint arthroplasty (TJA). These patients are more likely to require intensive care support, following surgery. We prospectively evaluated the need for intensive care admission and intervention in a consecutive series of 738 patients undergoing elective hip and knee arthroplasty procedures. The mean age was 60.6 years (18 to 91; 440 women, 298 men. Risk factors, correlating with the need for critical care intervention, according to published guidelines, were analysed to identify high-risk patients who would benefit from post-operative critical care monitoring. A total of 50 patients (6.7%) in our series required critical care level interventions during their hospital stay. Six independent multivariate clinical predictors were identified (p < 0.001) including a history of congestive heart failure (odds ratio (OR) 24.26, 95% confidence interval (CI) 9.51 to 61.91), estimated blood loss > 1000 mL (OR 17.36, 95% CI 5.36 to 56.19), chronic obstructive pulmonary disease (13.90, 95% CI 4.78 to 40.36), intra-operative use of vasopressors (OR 8.10, 95% CI 3.23 to 20.27), revision hip arthroplasty (OR 2.71, 95% CI 1.04 to 7.04) and body mass index > 35 kg/m(2) (OR 2.70, 95% CI 123 to 5.94). The model was then validated against an independent, previously published data set of 1594 consecutive patients. The use of this risk stratification model can be helpful in predicting which high-risk patients would benefit from a higher level of monitoring and care after elective TJA and aid hospitals in allocating precious critical care resources.

Elevated numbers of proliferating mononuclear cells in the peripheral blood of psoriatic patients correlate with disease severity.

Although psoriasis is characterized by the accumulation of activated proliferating lymphoid cells in the psoriatic skin lesion, it is not known whether these cells are activated and proliferating before entry into the psoriatic plaque. The current study evaluates the number and phenotype of proliferating lymphoid cells in the blood of psoriatic patients. Proliferation of peripheral blood mononuclear cells was evaluated on cytospun preparations of these cells using autoradiographic techniques after pulsing the mononuclear cells with 3H-methyl thymidine for 2 h. The phenotypes of the labeled peripheral blood mononuclear cells were determined combining autoradiography and immunohistochemistry with monoclonal antibodies directed at CD3, CD4, CD8, CD11c, CD22, and human leukocyte antigen-DR. The data demonstrated elevated numbers of proliferating lymphoid cells in the blood of psoriatic patients compared with normal nonpsoriatic volunteers (p < 0.01). Furthermore, the number of circulating proliferating mononuclear cells increased significantly with increasing psoriasis skin disease severity (correlation coefficient 0.95; p < 0.0001). When the phenotype of the proliferating cells in the blood was examined, the numbers of T cells (CD3+, CD4+, CD8+ cells), B cells (CD22+ cells), monocytes (CD11c+ cells), and human leukocyte antigen-DR+ cells were significantly elevated compared with nonpsoriatic skin (p < 0.01) and increased with increasing disease activity (correlation coefficient range 0.48-0.74; p < 0.05). The data suggest a generalized systemic activation of T, B, and monocytic cells that results in labeling of up to 0.16% of the circulating mononuclear cells with 3H-methyl thymidine (i.e., proliferating and presumably activated) when assayed in vitro.

Synthesis and carbonic anhydrase inhibitory activity of 4-substituted 2-thiophenesulfonamides.

A series of 4-substituted 2-thiophenesulfonamides was prepared from 3-thiophenecarboxaldehyde using metalation chemistry developed for 3-furaldehyde. Several of these compounds inhibit carbonic anhydrase II in vitro at concentrations of less than 10 nM. In addition, none of these compounds exhibit sensitization potential as determined from in vitro measurement of cysteine reactivity.

Seroepidemiology and evaluation of passive surveillance during 1988-1989 measles outbreak in Taiwan.

A seroepidemiological study was carried out to explore the risk factors of a measles outbreak that occurred among school children at a rural village (Li-Tse) in Taiwan. Among the 1166 participants, the percentage susceptible before the outbreak was 10.5% (122/1158) which was estimated as the sum of measles IgG-negative (29/1158) and IgM-positive (93/1166) individuals. Among 340 vaccinated children, 16 (4.7%) were measles IgM-positive and 10 (2.9%) were measles IgG-negative; therefore the vaccine failure rate was estimated to be 7.6% (26/340) and vaccine efficacy was 79.7% (95% confidence interval [CI] : 65.0-88.5). The most important risk factors for acquiring measles infection were the presence of other measles cases in the family (Odds Ratio [OR] = 32.5, P = 0.002) and the presence of more than two cases in a class (OR = 29.1, P = 0.003). The physician reporting rate was 6.1% (4/66), and the sensitivity of passive measles surveillance was only 4.3% (4/93) by active serosurvey. A concomitant rubella epidemic also amplified the inaccuracy of a passive reporting system based only on clinical diagnosis. Five children developed measles IgM but did not experience any symptoms, indicating that asymptomatic measles infection can occur. Our experience has highlighted three important areas for future measles elimination: (1) the need for serological evaluation of vaccinees, particularly those who were born during the introduction of mass immunization; (2) improvement in measles vaccine efficacy; and (3) further investigations on the role of asymptomatic transmission and susceptibles who remain after mass immunization.

Increase in the expression of human leukocyte antigen class I in human fibroblasts by soluble factors secreted from human cytomegalovirus-infected cells.

The human cytomegalovirus (HCMV) is known to downregulate the expression of the human leukocyte antigen (HLA) class I for escape from immune surveillance. In order to understand the HCMV immune evasion mechanism, expression of HLA class I on the surface of HCMV-infected cells was investigated. A decrease in the HLA class I expression was observed at higher MOI; whereas at a lower MOI a slight increase in the HLA class I expression was observed. When HCMV-infected and uninfected cells were separately prepared on coverslips and co-cultured, the increased HLA class I expression was observed in uninfected cells. Treatment of the uninfected cells with the culture supernatant from HCMV-infected cells resulted in an increase in the HLA class I expression. A biochemical analysis of the HCMV-infected cell culture supernatant revealed the presence of interferon (IFN) beta interleukin (IL)-1beta, and IL-6. The HLA class I-enhancing activity of the culture supernatant was mimicked by IFN beta, but not by IL1-beta or IL-6, and was partially reversed by pretreatment with an antibody to IFN beta. Therefore, it appears that the HCMV infection of human foreskin fibroblast cells induces interferon beta and other soluble factor(s) that are responsible for the up-regulation of the HLA class I expression.

Factors affecting human cytomegalovirus gene expression in human monocyte cell lines.

To understand the mechanisms for establishing and reactivating monocytes and macrophages from latency by human cytomegalovirus (HCMV), human monocyte cell lines were infected and HCMV gene expression was investigated. Indirect immunofluorescence assay (IFA) with monoclonal antibody to HCMV major immediate early (MIE) IE1 or IE2 proteins revealed that HCMV MIE genes were expressed at low levels in relatively more differentiated THP-1 cells with TPA treatment after virus infection (posttreatment). Less differentiated cells such as U937 or HL60 did not support MIE gene expression even after TPA treatment. If THP-1 cells were pretreated before virus infection with TPA and became differentiated at the time of HCMV infection, MIE gene expression increased by 5-6 fold. Therefore, the relative degree of monocyte cell differentiation appears to be an important factor for regulating HCMV gene expression. Further IFA studies using monoclonal antibodies specific for IE1 or IE2 proteins indicate that the sequence and general pattern of IE1 and IE2 gene expression in THP-1 cells treated with TPA were similar to those in permissive human fibroblast cells with some delay in time. Formation of the replication compartment detected with monoclonal antibody to HCMV polymerase accessory protein UL44 in THP-1 cells suggests a fully productive replication process of HCMV in these cells. Monocytes are known to be induced to differentiate by hydrocortisone (HC), tumor necrosis factor (TNF)-alpha or interferon (IFN)-gamma. HC, which is known to stimulate HCMV replication in permissive human fibroblast (HF) cells, enhanced HCMV gene expression by 2-3 fold in TPA-pre or posttreated THP-1 cells, but TNF-alpha or IFN-gamma had little effect. Nitric oxide (NO) is released by immune cells in the defense against foreign stimuli and was shown to inhibit HCMV gene expression in HF cells. Increasing NO by nitroprusside significantly reduced HCMV gene expression in THP-1 cells. Therefore, it appears that the expression of HCMV immediate early genes in THP-1 cells treated with TPA closely resembles those in permissive HF cells.

Detection of amplified Y chromosome-specific sequence by capillary electrophoresis with laser-induced fluorescence.

OBJECTIVE: To develop a sensitive method for genetic diagnosis using capillary electrophoresis with laser-induced fluorescence. DESIGN: Using male DNA diluted with female DNA as an example, ZFY gene from Y chromosome was amplified specifically by polymerase chain reaction (PCR) with fluorescence-labeled primers and detected by capillary electrophoresis with laser-induced fluorescence. SETTING: Laser operating laboratory. PARTICIPANTS: Human male and female DNA were extracted from healthy human male and female subjects. INTERVENTIONS: None. MAIN OUTCOME MEASURES: The concentration of human DNA was determined by using a spectrophotometer at an absorbance of 260 nm. RESULT: Deoxyribonucleic acid fragments amplified from a single copy of ZFY gene were detected by capillary electrophoresis with laser-induced fluorescence after 35 cycles of PCR amplification. CONCLUSION: This method is potentially applicable for rapid and sensitive detection of fetal Y chromosome DNA sequence in maternal circulation and of single-cell DNA diagnosis.

Experimental cerebral concussion. Part 1: An electron microscopic study.

Cerebral concussion was produced in rats by an iron pendulum hitting the external occipital protuberance. This resulted in loss of consciousness lasting from 3 to 10 minutes with prompt recovery and no focal neurological signs. The energy absorbed by the head at the impact was calculated to be about 1450 gm/cm. Light microscopic survey showed only minor pathological changes. However, electron microscopic observation revealed considerable alteration which began at 30 minutes, reached a peak at 1 hour, and disappeared at 24 hours after concussion. The salient changes included severe swelling of the neuronal mitochondria at the point of impact (occipital cortex), and extracellular edema at the site of contre coup (frontal lobe). Topographically, the most severe alteration was seen in structures at the craniospinal junction (medulla oblongata and upper cervical cord), consisting of both mitochondrial and edematous changes. Although there was no visible opening of the capillary interendothelial junctions, extravasated ferritin particles were accumulated in the edematous regions, indicating a transient increase in the permeability of the blood-brain barrier.

Electrochemistry of purine derivatives. 1: Direct determination for the antiviral drug 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine by anodic differential pulse voltammetry.

Differential pulse voltammetry at a stationary glassy carbon electrode was used for the sensitive and selective analysis of a potent new antiviral analogue of 2-deoxyguanosine in a pharmaceutical formulation. In the electrochemical method for analysis of 9-[1,(3-dihydroxy-2-propoxy)methyl] guanine (1), an electroactive internal standard (uric acid) was used. Linear peak current-concentration relationships were obtained at 1 concentrations of 0.4-2.0 mM, with a quantitation limit of 0.1 mM. Degraded solutions of 1 were assayed directly by differential pulse voltammetry and also by two chromatographic methods to demonstrate the specificity of the electrochemical method. The voltammetric method reliably provides accurate and reproducible results in considerably less time than conventional chromatographic analysis.

Arteriovenous fistula using transposed basilic vein in chronic hypotensive hemodialysis patients.

AIM: Chronic hypotension is not uncommon in uremic patients on regular hemodialysis. This subset of patients often requires multiple operations to maintain their vascular access due to frequent thrombosis and occlusion of the arteriovenous fistula. Our aims was to assess whether surgical intervention with the brachial artery-transposed basilic vein fistula is effective in chronic hypotensive hemodialysis patients. MATERIALS AND METHODS: Fifty-four hemodialysis patients with chronic hypotension were enrolled in this study. Most ofthem were referred from local hospitals. They were 23 men and 31 women. The brachial artery-transposed basilic vein arteriovenous fistula was performed in a period of 46 months at the teaching hospital. Primary patency was defined as the length of time from the fistula creation until the development of thrombosis or a complication that required operative revision ofthe fistula. Secondary patency was defined by whether the fistula could be salvaged by revision such that blood flow was maintained. RESULTS: There was no technical failure and none of these patients died due to the surgical operation. The primary patency rate was 89.80% at 1 year, 73.08% at 2 years, and 64.710% at 3 years. The secondary patency rate was 95.92% at 1 year, 84.62% at 2 years, and 76.47% at 3 years. CONCLUSIONS: Brachial artery-transposed basilic vein arteriovenous fistula may present good primary alternative vascular access in chronic hypotensive hemodialysis patients.

Incidence of bacterial respiratory pathogens and their susceptibility to common antibacterial agents.

Although most respiratory tract infections are caused by viruses, bacterial pathogens are responsible for higher morbidity and mortality. Because virtually nothing is known about the etiology of bacterial respiratory pathogens in Saudi Arabia, this study examined the incidence of these organisms in 5426 patients over a 1-year period. Of the bacterial pathogens isolated from 904 patients, the most common organism was Hemophilus influenzae (31%), followed by pneumococci (22%), Pseudomonas aeruginosa (16%), and others (31%). Because the first two organisms accounted for more than 50% of isolates, their susceptibility to commonly used antibiotics was also reviewed. The results are presented here.

Theoretical and computational investigations of nonlinear wave propagations in arteries. (I)--A theoretical model of nonlinear pulse wave propagations.

In this paper, a new theoretical model of nonlinear wave propagations in arteries with surrounding tissues was put forward. The equations of motion for the blood vessels and their peripheral tissues as a system have been derived. These equations were expressed in terms of the stresses of the vessel wall and fluid, and the geometry of the blood vessel. They can be used to solve numerically the problems for the propagations of nonlinear pulse waves in arteries together with the momentum and continuity equations of incompressible-viscous flow, as well as the constitutive equations of fluid and vessel wall. The numerical solutions can involve pressure, velocities and flowrate of the blood flow, as well as displacements, velocities and stresses of the vessel wall. These physical variables of propagations of pulse waves in arteries are all of significance physiologically and clinically.