Phantom and animal tissues for modelling the electrical properties of human liver

The dielectric properties of human liver were characterized over the frequency range of 0.3-3 GHz for freshly excised tissue samples of primary hepatocellular carcinoma, metastatic colorectal carcinoma, and normal liver tissues resected from the tumour margin. On average, the dielectric constant (epsilon(r)) of freshly excised human liver tumour was 12% higher than that of surrounding normal liver, and the electrical conductivity (sigma) of tumour was 24% higher. In order to establish suitable tissue models for human liver, the electrical properties were compared to measurements of homogenous phantom mixtures, in vitro bovine liver, and in vivo canine and porcine liver tissues. The data demonstrate that there are several animal tissues that can be used to model the average dielectric properties of human liver reasonably accurately, and use of the most readily available bovine liver appears well-justified, even when stored for up to 10 days in a refrigerator. Additionally, the dielectric properties of in vitro liver remained stable over a large temperature range, with sigma rising only 1.1%/ degrees C in porcine liver (15-37 degrees C) and 2.0%/ degrees C in bovine liver (10-90 degrees C), and epsilon(r) decreasing < or =0.2%/ degrees C in both tissues. This effort identifies homogeneous solid and liquid phantom models and several heterogeneous in vitro tissues that adequately model the dielectric properties of human liver tumours for use in quantitative studies of microwave power deposition in liver.

Patterns and determinants of acute psychiatric readmissions

Objectives . Deinstitutionalisation and shortage of psychiatric beds worldwide has led to extensive research into the risk fac- tors and interventions associated with rapid and recurrent admission to hospital. Little research of this nature has taken place in South Africa, particularly with regard to acute hospital admissions. This study attempted primarily to assess the effect of length of stay and administration of depot antipsychotics in hospital on time to readmission.Design. A retrospective cohort of 180 admissions was fol- lowed up for 12 months, after an index discharge, by means of multiple hospital and community-based record reviews. Each readmission was analysed as an event using a survival analysis model. Setting. Chris Hani Baragwanath Hospital, Gauteng.Subjects. A random sample of patients admitted during a 6-month period in 1996. Outcome measures. Time to readmission.Results. Two hundred and eighty-four admissions were analysed. The only factor that provided a significant protective effect was being married or cohabiting ( P = 0.015). Clinic attendance showed a slight protective effect early on but con- ferred a significantly higher risk of readmission on those who had been out of hospital for a long period ( P = 0.001). Only 21% of discharged patients ever attended a clinic. The overall risk of readmission was significantly higher in the first 90 days post discharge. Conclusions. The lack of impact of length of hospital stay and use of depot neuroleptics on time to readmission may indicate that patients are being kept for appropriate duration and that the most ill patients are receiving depot medication. Several sampling and statistical artefacts may explain some of our findings. These results confirm the worldwide difficulty in finding consistent and accurate predictors of readmission. Low rates of successful referral to community aftercare need to be addressed before their effectiveness can be reasonably assessed. The inherent instability of the post-discharge period is a potential area for further investigation and intensive management.

Investigation of bovine bone by resonant ultrasound spectroscopy and transmission ultrasound

The method of resonant ultrasonic spectroscopy (RUS) was evaluated for bovine bone and compared with the traditional wave transmission ultrasound method. In RUS, the resonance structure of a cubic or rectangular specimen is scanned. For some low-damping materials, a single measurement yields sufficient resonant frequencies to determine all of the anisotropic elastic constants. Bone has a high viscoelastic damping at ultrasonic frequency. Consequently, resonance peaks of a cubic specimen tend to overlap. Therefore, the usual RUS method must be modified for application to bone; even so, one cannot obtain all the elastic constants. Concurrent studies with transmission ultrasound were conducted. Results were used to generate a map of the elastic moduli vs position along the bone axis. Stiffness was greatest in the mid part of the bovine femur.

Familial aggregation of Barrett's oesophagus, oesophageal adenocarcinoma, and oesophagogastric junctional adenocarcinoma in Caucasian adults

BACKGROUND

Although familial clusters of Barrett's oesophagus and oesophageal adenocarcinoma have been reported, a familial predisposition to these diseases has not been systematically investigated.

AIMS

To determine whether Barrett's oesophagus and oesophageal (or oesophagogastric junctional) adenocarcinoma aggregate in families.

PATIENTS AND METHODS

A structured questionnaire eliciting details on reflux symptoms, exposure history, and family history was given to Caucasian case (n=58) subjects with Barrett's oesophagus, oesophageal adenocarcinoma, or oesophagogastric junctional adenocarcinoma, and to Caucasian control (n=106) subjects with symptomatic gastro-oesophageal reflux disease without Barrett's oesophagus. Reported diagnoses of family members were confirmed by review of medical records.

RESULTS

The presence of a positive family history (that is, first or second degree relative with Barrett's oesophagus, oesophageal adenocarcinoma, or oesophagogastric junctional adenocarcinoma) was significantly higher among case subjects compared with controls (24% v 5%; p<0.005). Case subjects were more likely to be older (p<0.001) and male (74% v 43% male; p<0.0005) compared with control subjects. In a multivariate logistic regression analysis, family history was independently associated with the presence of Barrett's oesophagus, oesophageal adenocarcinoma, or oesophagogastric junctional adenocarcinoma (odds ratio 12.23, 95% confidence interval 3.34-44.76) after adjusting for age, sex, and the presence of obesity 10 or more years prior to study enrollment.

CONCLUSIONS

Individuals with Barrett's oesophagus, oesophageal adenocarcinoma, or oesophagogastric junctional adenocarcinoma are more likely to have a positive family history of Barrett's oesophagus, oesophageal adenocarcinoma, or oesophagogastric junctional adenocarcinoma than individuals without Barrett's oesophagus, oesophageal adenocarcinoma, or oesophagogastric junctional adenocarcinoma. A positive family history should be considered when making decisions about screening endoscopy in patients with symptoms of gastro-oesophageal reflux.

Bed/population ratios in South African public sector mental health services

BACKGROUND

In post-apartheid South Africa, mental health service planners face critical decisions regarding appropriate and affordable inpatient care. Before a fashion of deinstitutionalisation is followed blindly in South Africa, effective community services should be in place and sufficient psychiatric beds should remain in hospitals for those who cannot be catered for in the community. In order to maintain the delicate balance between hospital and community-based services, it is essential that useful indicators of inpatient care are established. This study documents current bed/population ratios per 100 000 population in public sector mental health services in South Africa.

METHOD

A questionnaire was distributed to provincial mental health coordinators requesting psychiatric bed numbers in acute and medium-long stay facilities across all service levels. The information was supplemented by consultations with mental health coordinators in each of the nine provinces. Population data were obtained from preliminary findings of the 1996 census.

RESULTS

For acute facilities, the mean bed/population ratio was 13 (provincial range: 6-18) per 100 000 population. For medium-long stay facilities, it was 16 (provincial range: 0-29) excluding contracted facilities, and 35 (provincial range: 0-83) including contracted facilities per 100 000 population.

CONCLUSIONS

There were low levels of inpatient service provision in South Africa, and there was considerable variability between provinces. This study gives further support to the need to develop acute inpatient psychiatric services, reduce levels of chronic care where appropriate, and redirect resources towards the development of community-level residential and day-care services. It is crucial to develop accurate indicators to monitor this process.

Extremely low vertical-emittance beam in the accelerator test facility at KEK

Electron beams with the lowest, normalized transverse emittance recorded so far were produced and confirmed in single-bunch-mode operation of the Accelerator Test Facility at KEK. We established a tuning method of the damping ring which achieves a small vertical dispersion and small x-y orbit coupling. The vertical emittance was less than 1% of the horizontal emittance. At the zero-intensity limit, the vertical normalized emittance was less than 2.8 x 10(-8) rad m at beam energy 1.3 GeV. At high intensity, strong effects of intrabeam scattering were observed, which had been expected in view of the extremely high particle density due to the small transverse emittance.

Patterns and determinants of acute psychiatric readmissions

OBJECTIVES

Deinstitutionalisation and shortage of psychiatric beds worldwide has led to extensive research into the risk factors and interventions associated with rapid and recurrent admission to hospital. Little research of this nature has taken place in South Africa, particularly with regard to acute hospital admissions. This study attempted primarily to assess the effect of length of stay and administration of depot antipsychotics in hospital on time to readmission.

DESIGN

A retrospective cohort of 180 admissions was followed up for 12 months, after an index discharge, by means of multiple hospital and community-based record reviews. Each readmission was analysed as an event using a survival analysis model.

SETTING

Chris Hani Baragwanath Hospital, Gauteng.

SUBJECTS

A random sample of patients admitted during a 6-month period in 1996.

OUTCOME MEASURES

Time to readmission.

RESULTS

Two hundred and eighty-four admissions were analysed. The only factor that provided a significant protective effect was being married or cohabiting (P = 0.015). Clinic attendance showed a slight protective effect early on but conferred a significantly higher risk of readmission on those who had been out of hospital for a long period (P = 0.001). Only 21% of discharged patients ever attended a clinic. The overall risk of readmission was significantly higher in the first 90 days post discharge.

CONCLUSIONS

The lack of impact of length of hospital stay and use of depot neuroleptics on time to readmission may indicate that patients are being kept for appropriate duration and that the most ill patients are receiving depot medication. Several sampling and statistical artefacts may explain some of our findings. These results confirm the worldwide difficulty in finding consistent and accurate predictors of readmission. Low rates of successful referral to community aftercare need to be addressed before their effectiveness can be reasonably assessed. The inherent instability of the post-discharge period is a potential area for further investigation and intensive management.

Intra-abdominal actinomycosis with hepatic pseudotumor and xanthogranulomatous pyelonephritis in a 6-y-old boy

We report the case of a 6-y-old boy with actinomycosis, presenting as xanthogranulomatous pyelonephritis (XGP), hepatic pseudotumor and abdominal abscess. Symptoms included intermittent fever, abdominal pain and significant weight loss. Hepatic and renal tumor masses were suspected on sonography and computerized tomography. XGP and actinomycosis were proven by pathology. The patient recovered well with antibiotic alone.

Etiology and epidemiology of preterm premature rupture of the membranes

Preterm premature rupture of membranes continues to be a common complication of pregnancy with significant implications for perinatal outcome. Unfortunately, given the multiple risk factors that have been presented, which are reportedly associated with PPROM, attempts to reduce the incidence of this clinical event may seem daunting to the clinician. Despite this, one should attempt to address the potential risk factors that avail themselves to change. Unfortunately, although many risk factors have been identified, there are few randomized intervention trials for PPROM prevention. Examples of interventions documented to be beneficial include smoking cessation and screening for and treatment of chlamydial infections. These seem to be reasonable and logical interventions to consider in general, and may potentially have an effect on various causal agents of PPROM.

Epidemic of adenovirus-induced respiratory illness among US military recruits: epidemiologic and immunologic risk factors in healthy, young adults

Adenovirus (Ad)-induced acute respiratory illnesses resurged among civilian adults and selected military training populations in the United States during the late 1990s. We examined the epidemiologic and immunologic correlates of Ad-induced respiratory illnesses during a large outbreak at an Army basic training installation in southeast United States during a 9-day period in November 1997. A total of 79 recruits hospitalized with acute respiratory illnesses were evaluated during the outbreak period; confirmation of Ad infection by isolation of Ad-like cytopathic agents from throat cultures was detected in 71 (90%) of these patients. Serotyping of 19 (27%) of these 71 isolates identified the etiologic agent to be Ad type 4 (Ad4). In addition, 30 (81%) of 37 patients in whom paired sera were collected demonstrated significant increases (i.e., 4-fold or higher) in serum anti-Ad4 neutralizing antibodies. Anti-Ad4 immunity in new recruits was found to be very low (15 to 22%). A case-control study involving 66 of the 79 hospitalized cases and 189 non-ill controls from the same units was conducted. A lower risk of hospitalization for acute respiratory illnesses was documented for female recruits (odds ratio[OR] = 0.47, P <.05) whereas, a higher risk was noted for smokers (OR = 1.89, P <.05). Unit (training company) attack rates as high as 8 to 10% per week were documented and the outbreak quickly subsided after live, oral Ad types 4 and 7 vaccination was resumed in November 1997. Re-establishment of a military Ad vaccination program is critical for control of Ad-induced acute respiratory illnesses.

Giant aneurysm treated by bilateral cervical carotid artery to proximal middle cerebral artery bypass and balloon embolisation: a case report

The authors describe a case of a 59 year-old Chinese lady with a history of spontaneous left caroticocavernous fistula in 1988 treated by left internal carotid artery clipping and muscle embolisation. She subsequently presented with a subarachnoid haemorrhage in November 1997 secondary to rupture of an unclippable giant right internal carotid artery aneurysm. This was treated satisfactorily with bilateral cervical carotid artery to proximal middle cerebral artery bypass followed by balloon occlusion. Postoperatively, the patient has no neurological deficit and CT angiogram shows good patency of both grafts 6 months after surgery.

Noisy speech recognition using de-noised multiresolution analysis acoustic features

This paper describes a novel application of multiresolution analysis (MRA) in extracting acoustic features that possess de-noising capability for robust speech recognition. The MRA algorithm is used to construct a mel-scaled wavelet packet filter-bank, from which subband powers are computed as the feature parameters for speech recognition. Wiener filtering is applied to a few selected subbands at some intermediate stages of decomposition. For high-frequency bands, Wiener filters are designed based on a reduced fraction of the estimated noise power, making the consonant features much more prominent and contrastive. The proposed method is evaluated in phone recognition experiments with the TIMIT database. In the presence of stationary white noise at 10-dB SNR, the de-noised MRA features attain a phone recognition rate of 32%. There is a noticeable improvement compared with the accuracy of 29% and 20% attained by the commonly used mel-frequency cepstral coefficients (MFCC) with and without cepstral mean normalization (CMN), respectively. The effectiveness of the MRA features is also verified by the fact that they exhibit smaller distortion from clean speech.

Molecular basis of the Dombrock null phenotype

BACKGROUND

The Dombrock blood group system consists of two antithetical antigens, Do(a) and Do(b), and three high-incidence antigens, Gregory (Gy(a)), Holley (Hy), and Joseph (Jo(a)). The null phenotype of the Dombrock blood group system (Do(null)) was identified when it was found that Gy(a-) RBCs also lack Do(a), Do(b), Hy, and Jo(a).

STUDY DESIGN AND METHODS

DNA from three Gy(a-) persons was analyzed. PCR products for each of the three DO exons and their flanking intronic regions were sequenced in both directions. The cDNA from two of the people was subjected to PCR using primers in exon 1 and exon 3, and the products were sequenced.

RESULTS

The Do(null) phenotype is associated with a single nucleotide mutation in the acceptor splice site of DO (IVS1-2a>g), which results in outsplicing of exon 2.

CONCLUSION

Outsplicing of exon 2 is predicted to cause a -1 frameshift and a premature stop codon. Any product of such a transcript would lack the glycosyl-phosphatidylinositol-anchor motif, and RBCs would be devoid of the Do glycoprotein.

Factors influencing long-term home care utilization by the older population: implications for targeting

This research was designed to explore factors that affect the choice of long-term care modalities in the older population and to discuss the appropriate target population of home health care services within the entire long-term care system. The study subjects' activities of daily living limitations, cognitive status, and sociodemograhic data at the time of admission were obtained from retrospective chart reviews. The sample included 134 older subjects who were receiving long-term care from a Long-Term Home Health Care Program or a nursing home in New York City. The results indicated that Long-Term Home Health Care Program use by older persons was characterized by a higher rate of being admitted from private homes, less cognitive impairments, less limitations in activities of daily living, and younger age than older patients who were nursing home residents. Consequently, in the choice of different care modalities, health-related factors of the older population were found to be more important predictors than sociodemographic characteristics or support system. The implication to both nurses and researchers is the development of eligibility criteria that captures the unique characteristics of disabled older persons in each of the different long-term care programs to serve them better in a cost-effective manner.

Prostate shape and symptom score in benign prostatic hyperplasia

Prostates of the same volumes were found to have very variable shapes, that is, combinations of variably elongated width, height, and lengths. These were believed to be possible causes of the differences in the severity of both the obstructions and symptoms in the prostates even when their volumes were similar. We measured the transverse (width), anterior-posterior (height) and longitudinal (length) diameters of the prostates and the transition zone, and their calculated volumes using transrectal ultrasonography. To establish the relationship between the International Prostate Symptom Score (IPSS) and each of the dimensional parameters of the transition zone and the total prostate, 105 consecutive patients (mean age 66.43 +/- 9.24 years with a range o6f 46 to 90) who had voiding dysfunctions that were presumably related to BPH were analyzed using the t-test. Patients with conditions other than BPH were excluded. The results were as follows: 1. There was no significant correlation between the IPSS and any prostate volume parameter in the constant prostate volume conditions, because of the small numbers in each group. However, in the analysis of the total number of cases in all the volume categories, a significant correlation was found between the IPSS and some prostate dimensions; i.e., the longitudinal parameters in the total prostates (p < 0.01), and the transverse (p < 0.05) and longitudinal parameters (p < 0.05) in the transition zones. 2. Further investigations of the statistics of these significant parameters showed that prostates that were longer than 4 cm had significantly more severe symptoms than prostates shorter than 4 cm (p < 0.05), and that prostates with a ratio of length in the transition zone to the length in the total prostate ratio that was greater than 0.8 had significantly higher symptom scores than those with lower ratios (p < 0.05). When evaluating patients who have BPH, it is important to consider the shape of prostate. More aggressive treatment may be indicated in cases where the transition zone lengths exceeds 4 cm and the transition zone to total prostate length ratio exceeds 0.8.

Requirement for the L-type Ca(2+) channel alpha(1D) subunit in postnatal pancreatic beta cell generation

Pancreatic beta cells are the source of insulin, which directly lowers blood glucose levels in the body. Our analyses of alpha(1D) gene-knockout (alpha(1D)(-/-)) mice show that the L-type calcium channel, alpha(1D), is required for proper beta cell generation in the postnatal pancreas. Knockout mice were characteristically slightly smaller than their littermates and exhibited hypoinsulinemia and glucose intolerance. However, isolated alpha(1D)(-/-) islets persisted in glucose sensing and insulin secretion, with compensatory overexpression of another L-type channel gene, alpha(1C). Histologically, newborn alpha(1D)(-/-) mice had an equivalent number of islets to wild-type mice. In contrast, adult alpha(1D)(-/-) mice showed a decrease in the number and size of islets, compared with littermate wild-type mice due to a decrease in beta cell generation. TUNEL staining showed that there was no increase in cell death in alpha(1D)(-/-) islets, and a 5-bromo-2' deoxyuridine-labeling (BrdU-labeling) assay illustrated significant reduction in the proliferation rate of beta cells in alpha(1D)(-/-) islets.

Systemic lupus erythematosus and antiphospholipid syndrome in children and adolescents

Systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) can be associated with significant morbidity in children and adolescents. Renal involvement in SLE appears to be more severe and more frequent in the pediatric age group, with the major predictors for poor outcome being the severity of histopathologic lesions, severity of renal impairment at diagnosis, and hypertension. In addition to currently recognized cardiovascular and pulmonary involvement, accelerated atherosclerosis is of increasing concern in young individuals with SLE, because of both disease effects and medication usage. Neuropsychiatric SLE seen in childhood ranges from subtle cognitive dysfunction to severe central nervous system involvement; however, there is controversy over the value of different diagnostic studies. APS in children may be associated with SLE, idiopathic, or associated with viral infections. Systemic anticoagulation is recommended for patients with thrombotic events, but long-term management has not been well studied in children.

Chips and Qi: microcomponent-based analysis in traditional Chinese medicine

Over the last 50 years or so Traditional Chinese medicine (TCM) has been subject to intensive basic and clinical research. Although the effectiveness and remarkable safety of TCM have been documented after controlled clinical studies, there are several herbal and animal parts that are toxic or difficult to identify. DNA polymorphism-based assays have recently been developed for the identification of herbal medicines. In this approach, small amounts of DNA are amplified by the polymerase chain reaction and the reactions products are analyzed by gel electrophoresis, sequencing, or hybridization with species-specific probes. With the DNA based identification of TCM materials as an example, chip-based analytical micro devices were developed with the goal of fabricating an integrated device that will enable sample preparation, amplification, and analysis on a single microchip-based device ("lab-on-a-chip"). The application of a silicon-based polymerase chain reaction microreactor and a DNA microarray for the DNA sequence-based identification of toxic medicinal plants is reported here.

Tyrosine cross-linking of extracellular matrix is catalyzed by Duox, a multidomain oxidase/peroxidase with homology to the phagocyte oxidase subunit gp91phox

High molecular weight homologues of gp91phox, the superoxide-generating subunit of phagocyte nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase, have been identified in human (h) and Caenorhabditis elegans (Ce), and are termed Duox for "dual oxidase" because they have both a peroxidase homology domain and a gp91phox domain. A topology model predicts that the enzyme will utilize cytosolic NADPH to generate reactive oxygen, but the function of the ecto peroxidase domain was unknown. Ce-Duox1 is expressed in hypodermal cells underlying the cuticle of larval animals. To investigate function, RNA interference (RNAi) was carried out in C. elegans. RNAi animals showed complex phenotypes similar to those described previously in mutations in collagen biosynthesis that are known to affect the cuticle, an extracellular matrix. Electron micrographs showed gross abnormalities in the cuticle of RNAi animals. In cuticle, collagen and other proteins are cross-linked via di- and trityrosine linkages, and these linkages were absent in RNAi animals. The expressed peroxidase domains of both Ce-Duox1 and h-Duox showed peroxidase activity and catalyzed cross-linking of free tyrosine ethyl ester. Thus, Ce-Duox catalyzes the cross-linking of tyrosine residues involved in the stabilization of cuticular extracellular matrix.